©
® o©
TECHNICAL REPORTS SERIES No 154
IAEA Research Contracts Fourteenth Annual Report
INTERNATIONAL ATOMIC ENERGY AGENCY, VIENNA, 1974 IAEA RESEARCH CONTRACTS The following States are Members of the International Atomic Energy Agency :
AFGHANISTAN HAITI PAKISTAN ALBANIA HOLY SEE PANAMA ALGERIA HUNGARY PARAGUAY ARGENTINA ICELAND PERU AUSTRALIA INDIA PHILIPPINES AUSTRIA INDONESIA POLAND BANGLADESH IRAN PORTUGAL BELGIUM IRAQ ROMANIA BOLIVIA IRELAND SAUDI ARABIA BRAZIL ISRAEL SENEGAL BULGARIA ITALY SIERRA LEONE BURMA IVORY COAST SINGAPORE BYELORUSSIAN SOVIET JAMAICA SOUTH AFRICA SOCIALIST REPUBLIC JAPAN SPAIN CAMEROON JORDAN SRI LANKA CANADA KENYA SUDAN CHILE KHMER REPUBLIC SWEDEN COLOMBIA KOREA, REPUBLIC OF SWITZERLAND COSTA RICA KUWAIT SYRIAN ARAB REPUBLIC CUBA LEBANON THAILAND CYPRUS LIBERIA TUNISIA CZECHOSLOVAK SOCIALIST LIBYAN ARAB REPUBLIC TURKEY REPUBLIC LIECHTENSTEIN UGANDA DENMARK LUXEMBOURG UKRAINIAN SOVIET SOCIALIST DOMINICAN REPUBLIC MADAGASCAR REPUBLIC ECUADOR MALAYSIA UNION OF SOVIET SOCIALIST EGYPT, ARAB REPUBLIC OF MALI REPUBLICS EL SALVADOR MEXICO UNITED KINGDOM OF GREAT ETHIOPIA MONACO BRITAIN AND NORTHERN FINLAND MONGOLIA IRELAND FRANCE MOROCCO UNITED STATES OF AMERICA GABON NETHERLANDS URUGUAY GERMAN DEMOCRATIC REPUBLIC NEW ZEALAND VENEZUELA GERMANY, FEDERAL REPUBLIC OF NIGER VIET-NAM GHANA NIGERIA YUGOSLAVIA GREECE NORWAY ZAIRE, REPUBLIC OF GUATEMALA ZAMBIA
The Agency's Statute was approved on 23 October 1956 by the Conference on the Statute of the IAEA held at United Nations Headquarters, New York; it entered into force on 29 July 1957. The Headquarters of the Agency are situated in Vienna. Its principal objective is "to accelerate and enlarge the contribution of atomic energy to peace, health and prosperity throughout the world".
(C) IAEA, 1974
Permission to reproduce or translate the information contained in this publication may be obtained by writing to the International Atomic Energy Agency, Kärntner Ring 11, P.O. Box 590, A-1011 Vienna, Austria.
Printed by the IAEA in Austria April 1974 TECHNICAL REPORTS SERIES No. 154
IAEA RESEARCH CONTRACTS
Fourteenth Annual Report
INTERNATIONAL ATOMIC ENERGY AGENCY VIENNA, 1974 IAEA RESEARCH CONTRACTS IAEA, VIENNA, 1974 STl/DOC/lO/154 FOREWORD
This volume contains the summaries of all final reports received during 1973 in relation to research supported under contract (which provides for a financial contribution from the Agency) or agreement (under which no financial contribution is provided). Every summary in this book has been reviewed or prepared by that member of the Agency's scientific staff who has beenmost closely connected with the particular branch of research concerned. The scientific data are the responsibility of the contractor, though the Agency is responsible for any additional observations. It is the policy of the Agency strongly to encourage publication in the open scientific literature of results of work done under contract or agree- ment, and any articles so published are listed at the end of each summary. Microfiche copies of the complete final reports may be obtained from
INIS Section Division of Scientific and Technical Information International Atomic Energy Agency Kärntner Ring 11 (P.O. Box 590) A-1011 Vienna Austria on payment in advance of $0. 65 per document (or equivalent in national currencies) or in exchange for an IAEA microfiche clearing-house coupon. Governments of Member States of the IAEA may obtain free, on request, up to three microfiche copies of any report from the above address. Requests should mention the relevant report number, which is given at the head of each summary in this book.
CONTENTS
NUCLEAR TECHNOLOGY
NUCLEAR POWER AND REACTORS
Research Contract No. 706 Cross-flow and mixing between semi-open channels in nuclear reactors 3 Research Contract No. 934 High sensitive detection of rare fission gas release of fuel elements of water cooled reactors 5 Research Contract No. 1027 Determination of negative reactivities in a subcritical assembly, by means of neutron statistical fluctuations 7 Research Contract No. 1045 The economic comparison of nuclear reactors of 350 and 500 MW(e) for developing countries 9 Research Contract No. 1079 Determination of impurities in uranium plant products 12 Research Contract No. 1112 Guide on nuclear fuel-cycle cost evaluation 14 Research Contract No. 1184 International comparison of chemical dosimeters for in-pile use 16 Research Contract No.1328 Development of cultures of Thiobacillus ferrooxidans for the microbiological leaching of sulphide and uranium ores (part of a co-ordinated program of research on the bacterial leaching of uranium ores) 19
WASTE MANAGEMENT
Research Contract No. 1213 Calculations on and building of mathematical models of processes involved in the deposition of wastes in water 23
PHYSICS AND CHEMISTRY
Research Contract No.818 Radio-spectroscopic investigation: the ordering of magnetics containing isotopes 57 Fe 2 5 Research Contract No. 844 Nuclear and hyperfine interaction measurements by angular correlation and Mossbauer technique 28 Research Contract No, 895 Chemical behaviour of radionuclides in natural waters, and their interaction with chelating agents 31 Research Contract No, 1141 Development and industrial application of a high sensitivity Mössbauer spectrometer 33
RADIOISOTOPES AND RADIATION APPLICATIONS
AGRICULTURE
Research Agreement No. 418 The use of isotopes and radiation in studies on etiology, effects and treatment of parasitic diseases in domestic animals (part of a co-ordinated program) 37 Research Agreement No. 507 The use of radioisotopes as reference substances in studies of intestinal absorption and digestibility (part of a co-ordinated program of research on the use of isotopes and radiation in studies on etiology, effects and control of parasitic diseases in domestic animals) 41 Research Agreement No. 520 Physiology of nutrition of Hypoderma-larvae in comparison with facultative and obligate parasitic fly-larvae (part of a co-ordinated program on the control of animal insect pests by the sterile-male technique) 43 Research Contracts and Agreements Nos 523, 608, 614, 622, 623, 639, 654, 655, 680, 716, 728, 861, 956 and 992 Co-ordinated program of research on the use of isotopes and radiation in wheat fertilization studies 45 Research Contract No. 541 Development of artificial feeding and mass-rearing of the tsetse fly Glossina morsitans and G. sub-morsitans (part of a co-ordinated program on the control of animal insect pests by the sterile-male technique) 49 Research Contract No. 612 Haemal and environmental factors regulating tsetse fly feeding activity (part of a co-ordinated program on the control of animal insect pests by the sterile-male technique) 52 Research Contract No. 729 Use of isotopes in studies on the nutrition of groundnuts (part of a co-ordinated program of research on the use of isotopes and radiation in studies of physico-chemical relationships of soils and plants) 53 Research Contract No. 758 Mass rearing methods for important lepidopterous pests of South East Asia (part of a co-ordinated program of rice insect control and eradication) 55 Research Agreement No. 969 Fate and significance of labelled pesticide residues in rice (part of a co-ordinated program of research on the fate and significance of foreign substances in food) 57 Research Contract No. 985 Irradiation of Theileria parva, the causative organism of East Coast Fever of cattle, in its tick vector (part of a co-ordinated program on the use of isotopes and radiation in studies of the etiology, effects and control of parasitic diseases in domestic animals) 59 Research Contract No. 1070 Control of the fall webworm (Hyphantria cunea Drury) by gamma sterilization of males (part of a co-ordinated program on the use of the sterile-male technique of control of lepidopterous insects attacking fruit and forest trees) 62 Research Contract No. 1204 Field performance of released normal and radiation sterilized olive fruit flies in a grove in Northern Greece (part of a co- ordinated program on the control or eradication of fruit flies by the sterile-male technique) 65
FOOD TECHNOLOGY
Research Contract No. 839 Irradiation preservation of Korean fish and shellfishery products 67 Research Contract No. 929 Electrical (AC) resistance of irradiated fish for quality control and detection of irradiation treatment 69 Research Contract No. 931 Cell count reduction in seasoning, particularly in ground paprika, by radiation treatment (part of a co-ordinated program of research on the shelf-life extension of irradiated fruits and vegetables) 71 Research Agreement No. 974 Irradiation of dehydrated fruits (figs, prunes, raisins, etc. ) at disinfestation doses: chemical and microbiological aspects (part of a co-ordinated program of research on the shelf- life extension of irradiated fruits and vegetables) 74
INDUSTRY Research Contract No. 870 Wood-polymer combinations using gamma radiation 77 Research Contract No. 1020 Application of radioactivation methods to the determination of trace quantities of gold in rocks, water and plants (part of a co-ordinated program on the use of activation analysis in geochemical and geobotanical prospecting for ores and minerals) 79
MEDICINE
Research Contract No. 672 Applications of radioimmunoassay techniques in growth hormone studies in undernourished children and adolescents with retarded growth 81 Research Contract No. 732 Double-isotope techniques for the study of the mechanisms regulating aldosterone secretion and biosynthesis in experimental and clinical conditions associated with hyperaldosteronism 83 Research Contract No. 762 Development of new radiopharmaceuticals 85 Research Contract No.786 Applications of radioisotope techniques in the clinical evaluation of cardiac patients during treatment and rehabilitation 88 Research Contract No. 789 Application of radioisotope techniques in studies of abnormalities in male sexual development 91 Research Contract No. 814 Development of radioimmunoassay techniques for the measurement of protein hormones 93 Research Contract No. 815 Iron nutrition in Mexico (part of a joint IAEA/WHO co-ordinated research program on the use of radioisotopes in iron nutrition studies) 95 Research Contract No.825 The availability of foodstuff and supplemental iron from mixed diets based on wheat (part of a joint IAEA/WHO co-ordinated research program on the use of radioisotopes in iron nutrition studies) 98 Research Contract No.850 Application of radioimmunoassay techniques in investigations of plasma insulin in Ugandans 101 Research Contract No. 851 Applications of in vitro radioisotope techniques in studies on the endocrine status of the Nigerian 103 Research Contracts Nos 858 and 860 Studies of a radioactive gel diffusion technique and its applicability to immunological studies on African populations; Studies of a radioactive gel diffusion technique and its applications to immunology 105 Research Contract No. 945 The use of 59Fe-ferrioxamine in studies of the effect of the depot iron content of the body on the serum iron level in viral hepatitis 109 Research Contract No. 1182 Development of a radiochemical separation scheme for the determination of trace elements in biomedical samples by activation analysis (part of a co-ordinated research program on the medical applications of activation analysis) Ill
DOSIMETRY
Research Contract No.837 Direct internal radiation dosimetry of radiopharmaceuticals by improved needle-type fluoroglass dosimeter 113 HYDROLOGY
Research Contract No. 809 Application of isotopic techniques in the hydrological study of the Aconcagua River Basin 115 Research Contract No. 812 Determination of 180/160 ratio in precipitation (rain and snow) ... 117 Research Contract No. 847 Investigation of the connection of the subsoil water with underground water in the Nile Delta (Egypt) using isotopes 119
PROTECTION OF MAN AND HIS ENVIRONMENT
RADIATION BIOLOGY
Research Agreement No. 503 and Research Contract No. 873 Irradiation induced changes in red blood cell metabolism and membrane structure 123 Research Contract No. 722 The succession of plankton communities and their primary productivity in artificial water reservoirs in Nigeria 12 5 Research Agreement No. 795 Effect of irradiation on the microecosystem of sewage (part of a co-ordinated program of research on the study and improvement of biosphere resources) 128 Research Contract No. 833 Reduction in radiosensitivity of mammalian cells by chemical means 131 Research Contract No. 846 Characterization of useful mutations in fungi induced by radiation and radioisotopes and the study of their biosynthetic products (part of a co-ordinated program of research on radiation microbiology) 133 Research Contract No.862 Inactivation or attenuation of protozoa by ionizing radiation oriented toward the preparation of vaccines 136 Research Contract No. 916 Identification of radiosensitive stages during the differentiation of immunocompetent cells 139 Research Contract No. 1011 The relative biological effectiveness of beta, X-rays, and 27.2 MeV deuterons for oxidative enzymes in epidermis 142
RADIOLOGICAL SAFETY
Research Contract No. 530 Investigations on thermoluminescence dosimetry 145 Research Contract No. 646
Radon and Si02 toxicity on rats' lungs 148 Research Contract No.791 Chromosome aberrations in the peripheral blood lymphocytes of people living or working in areas of higher atmospheric concentration of natural radon-222 and its daughters in Badgastein, Austria 150 Research Contract No.894 Correlation of internal radiation doses from incorporated isotopes and chromosome aberrations 153 Research Contract No. 896 Development of a method of selective measurement of thermal neutron and gamma-radiation exposures in a mixed radiation field for normal and accident conditions by means of thermoluminescent dosimeters of multiple use (part of a co-ordinated program on nuclear accident dosimetry) 155 Research Contract No.897 Studies on factors affecting accuracy of individual dose measurements by means of radiophotoluminescent (R. P. L. ) and thermoluminescent (T. L. ) dosimetric systems (part of a co-ordinated program on nuclear accident dosimetry) 158 Research Contract No. 937 Studies on the retention and the elimination of radioactive iodine from the human body 161
SAFEGUARDS
Research Agreement No. 942 Study of a non-destructive measurement method for highly enriched U-Al alloy plate fuel 167 Research Contract No. 983 Integral experiments restricted at key points of control for highly enriched fuel element cycle from fabrication plant to dissolver of reprocessing plant 170 Research Contract No. 993 Measurement of neutron decay constant in a highly subcritical reactor as a safeguard method 172 Research Contract No. 994 Integral safeguards experiment at the Novo-Voronezh LWR Power Reactor Plant 174 Research Contract No. 1025 Tamper resistant instrumentation for a chemical reprocessing plant 176 Research Contract No. 1072 Fingerprinting and containment of fuel elements for safeguard of an Atucha-type reactor 179 Research Contract No. 1099 Systems study on safeguards in enrichment plants 181 Research Contract No.1209 Optimization of safeguards effort 183 NUCLEAR TECHNOLOGY
NUCLEAR POWER AND REACTORS WASTE MANAGEMENT PHYSICS AND CHEMISTRY
NUCLEAR POWER AND REACTORS
RESEARCH CONTRACT No. 706
Summary of final report IAEA-R-706-F
TITLE
Cross-flow and mixing between semi-open channels in nuclear reactors.
RESEARCH INSTITUTION
Technion Research and Development Foundation Ltd., Haifa, Israel.
PRINCIPAL SCIENTIFIC INVESTIGATOR
G. Hetsroni.
PERIOD OF CONTRACT
1 January 1969 - 28 February 1973.
SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT
The thermal design of nuclear reactors requires that proper account be taken of the possible overheating of a single channel in a rod bundle. The severity of such overheating is determined by the subsequent dissipation of the overheat between the channel in question and its neighbours, this dissipation being partly due to turbulent diffusion. The objective of the present research was to advance the state of the knowledge of turbulent mixing in rod-bundle flow. To this end two lines of research were pursued: (a) development of a Monte Carlo type numerical method of calculation of thermal diffusion in turbulent channel flow; and (b) measurement of detailed characteristic of turbulent flow in rod-bundle channels. Though both the basic Monte Carlo concept and the experimental technique are firmly based on existing methods, their application to the present problem has not, apparently, been attempted before.
EXPERIMENTAL METHODS
In the computational study the research consisted in applying the Monte Carlo method of computation, which had previously been used for neutron diffusion, radiation and heat conduction, to a problem of turbulent convection in a channel of rather irregular geometry. This was done in two stages. First, the problem was studied for a cylindrical tube geometry and a point source problem was chosen. The basic Monte Carlo concept was successfully applied, but it appeared that for the point source problem a forward (in the flow direction) rather than backward walk was advantageous.
3 Both were compared with a conventional finite-difference program. Sub- sequent to the completion of the cylindrical tube programs, the basic idea was extended to the rod-bundle channel geometry, allowing for arbitrary diameter, pitch, temporal-mean axial velocity distribution, and RMS axial turbulence distribution. This again was compared with a conventional finite-difference program with good results. In the experimental part a facility was constructed for measuring the axial velocity and turbulence distributions in a rod-bundle channel. The measurements are made by hot-film anemometer, with the usual auxiliary equipment. The maximum flow rate of the test loop is about 30 m3/h, corresponding to Re = 10 in a 58-mm diameter, 63.8-mm square pitch channel. The actual test section is removable, allowing the installation of sections with different rod diameters and pitch sizes. The hot-film was mounted on a traversing mechanism, which could execute radial and angular motion centred on the axis of one of the rods forming the channel.
RESULTS OBTAINED
Several programs were written, the main ones being: GAD-12 — cylindrical tube, Monte Carlo, backward walk; NEEDLE and NEEDLE 1 - cylindrical tube, Monte Carlo, forward walk; NEEDNUM, and NEEDNUM 1 - cylindrical tube, conventional; GAD-15 — rod bundle channel, Monte Carlo, backward walk; MOCCA — rod bundle channel, Monte Carlo, backward walk; and ALGRA — rod bundle channel, conventional. Full listings and detailed explanations of these programs are given in Progress Reports Nos 3, 4 and 5 (final). In the experimental study measurements of temporal-mean axial velocity distributions and of RMS axial turbulence distributions were obtained for a square-array rod channel with 58-mm rod diameter and pitch/diameter ratio 1.1. The mean velocities were 1.21, 2. 30 and 3. 36 m/s, corresponding to Reynolds numbers 3. 80 X 104, 7. 22 X 104 and 10. 54 X 104. Measurements were taken over 2 of the -8 symmetrical 45° segments forming a channel with the traversing mechanism stepping 5° in angle and 1 mm in radius. Detailed maps of these measurements are presented in the Final Report.
CONCLUSIONS
The main conclusion is,that a Monte Carlo method can, indeed, be successfully applied to a problem of turbulent diffusion in a complex geometry. From the point of view of computer time, it appears that for problems of small to moderate grid size a Monte Carlo program is less economical than a conventional one because of the large number of random walkers required. However, the Monte Carlo program would be preferable for large grid sizes, in which its advantage is that (a) the program itself requires less core memory, and (b) the program operates basically in integer mode and therefore is not subject to error accumulation, which becomes prohibitive for a conventional program with large grid sizes. In the experimental part detailed maps of velocity and turbulence were obtained, which can now serve as input data for further calculations.
4 RESEARCH CONTRACT No. 1027
Summary of final report IAEA-R-934-F
TITLE
High sensitive detection of rare fission gas release of fuel elements of water cooled reactors.
RESEARCH INSTITUTION
Department of Reactor Physics, Atominstitut der Österreichischen Hochschulen, Vienna, Austria.
PRINCIPAL SCIENTIFIC INVESTIGATOR
C.M. Fleck.
PERIOD OF CONTRACT
1 September 1970 - 30 September 1973.
SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT
Contamination of reactor fuel elements and core components with fissionable material may offset the attempt to detect cladding failure through measurement of the activity level of any released fission gas. Owing to the difference in the release mechanism between intact and defective fuel elements, detection of defective elements could be better indicated by a change in the isotopic composition of the released rare gases than by a change in the absolute level of the fission gas activity. Investigations were performed to determine the fission gas release parameters for uranium-zirconium-hydride. The release of the different fission gas isotopes was then calculated and compared with measured values for both intact and defective fuel elements at any operation state of the reactor and at any power level.
EXPERIMENTAL METHODS
The study was carried out in two parts: (a) determination of fission gas release from UZr fuel samples during irradiation, and (b) measure- ment of the fission gas release from whole fuel elements after irradiation. In the first experiment a uranium-zirconium-hydride sample was placed in the central irradiating thimble of a TRIGA MARK II reactor, within which the temperatures could be fixed. Having reached saturation activities, the released rare gas isotopes were routed to a Ge(Li)-detector and analysed by a 4000 multichannel analyser. The released I and Br isotopes could be trapped by several filters. In the second experiment the fission gas release of about 30 fuel elements of a TRIGA MARK II reactor was measured. After reactor
5 operation, the elements were put in a container connected to a degassing loop. The surrounding water of the elements was continuously pumped to the degaser allowing for the rare gases to be blown to the detector.
RESULTS OBTAINED
From the first experiment the fission gas release parameters were defined and measured, totally independent from temperature, neutron flux, etc. By means of these parameters the release from UZr fuel elements of any fission gas isotope of interest could be calculated. From the second experiment the fission gas release of isotopes from fuel elements of a TRIGA MARK II reactor was analysed. It could be shown that for most of the elements the measured release of fission gases resulted from the uranium contamination of the cladding surface. Only two elements showed a highly significant difference in the isotopic composition of the released rare gases. By knowing the release parameters measured in Experiment 1 and assuming a small leak in the cladding, the change in the isotopic composition measured in Experiment 2 could then be calculated within an acceptable error.
CONCLUSIONS
From these investigations it has been demonstrated that from the known gas release mechanism measurement of the isotopic composition of released fission gas can give information about the integrity of the cladding material. These results are of importance with regard to reactor safety. The research shows, in fact, a way to detect cladding failures when large contamination of the core may offset any possible correlation between cladding failure and activity level.
PAPER PUBLISHED ON WORK DONE UNDER THE CONTRACT
FLECK, C.M., BÖCK, H., ERBER, H., BRUNNER, P., The change in the fission gas release by knockout as a function of burnup, Atomkernenergie 20 (1972) 51.
6 RESEARCH CONTRACT No. 1027
Summary of final report IAEA-R-1027-F
TITLE
Determination of negative reactivities in a subcritical assembly, by means of neutron statistical fluctuations.
RESEARCH INSTITUTION
Division of Reactor Physics, Junta de Energía Nuclear, Madrid, Spain.
PRINCIPAL SCIENTIFIC INVESTIGATOR
J. Montes Ponce de León.
PERIOD OF CONTRACT
1 July 1971 - 30 June 1972.
SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT
The objective of the research was to study the application of Feynman's method to the determination of negative reactivities, p, and some other parameters such as effective delayed neutron fraction, ß, and effective lifetime of neutrons, SL, in the subcritical assembly JEN-2. Control element calibration and fuel-importance function measurements were also a part of the research program.
EXPERIMENTAL METHODS
The experimental method was based on the Feynman's formula describing the variance to mean ratio of the number of counts, c, collected during a time T by a neutron detector.
aT 2 2 1 - e' c -(c) ev (" -1) (LdL) = 1 + y c (v)2 \ ¡L J a T where e is the efficiency of the counter, v is the mean number of neutrons released per fission, and
The experimental equipment included: (a) BF3 proportional detector; (b) input unit comprising an amplifier, a window discriminator and a pulse former; (c) pulse generator giving signals to start experiment cycle; and (d) digital computer with an 800-channel magnetic memory. The reactor was subcritical even when all the control plates, situated at the core periphery, were completely withdrawn. The neutron level was kept constant by means of a neutron source. Various positions were tried
7 for the detector and it was found that the experiment could be conducted only when the detector was located in a space normally occupied by a fuel element. In the experiments, the numbers of counts were measured for successive channels of equal width. Statistical analysis was carried out to determine the best procedure of sampling and the criteria for selecting the reliable samples.
RESULTS OBTAINED
Two types of experiments were carried out: In the first one the level of subcriticality was varied by inserting one of the control plates into seven different positions. Various approaches of the treatment of the experimental data obtained were analysed. It was found that jS/jg = (127. 5 ± 8. 25)s~1. Through determination of the differences between the reactivities corresponding to various rod positions, the differential and integral calibration of the control plate was made. Its total control weight is (0. 615 ± 0. 039) $. To determine separately the parameters ß and £ the calibration of the control plate was made once more (but in this case in punits) using the increasing period method. It was found that ß = p/$ = 0. 00765, i = (6. 00 ± 0. 36) 10~5 s and e = 5. 99 X 10~4 detections per fission. For the second experiment four fuel plates were added in positions from A-2 to A-5. The experiment consisted of withdrawing these plates successively and making measurements at each stage in the same way as in the previous experiment. The control plates remained in the utmost position. Five corresponding stages were investigated. It was found that ß/£ = 130. 8 and e = 6. 71 X 10~4 detections per fission. During the experi- ment the reactivities produced by a fuel plate in the various positions of the region A of the reactor were determined as well.
CONCLUSIONS
The deviations between the theoretical and experimental values of the parameter 1 + y are less than the standard deviation. The determinations of the parameter ß/i from both experiments are in good agreement and they also agree with the value obtained for this parameter earlier by the pulsation method (125. 1). The differential calibration of the control plate made by Feynman's method agrees with those obtained by the period method in this research and by the rod drop method earlier. The quotient of the values ß and Í, which were obtained by comparing results of Feynman's and period methods (127.4), is in good agreement with the values determined by Feynman's method alone.
8 RESEARCH CONTRACT No. 1027
Summary of final report IAEA-R- 1045-F
TITLE
The economic comparison of nuclear reactors of 350 and 500 MW(e) for developing countries.
RESEARCH INSTITUTION
Institute for Nuclear Energy, Technical University of Istanbul, Turkey.
PRINCIPAL SCIENTIFIC INVESTIGATOR
N. Aybers.
PERIOD OF CONTRACT
1 September 1971 - 31 August 1973.
SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT
To discuss in detail the economics of nuclear power plants and illustrate the approach to some of the problems found by developing countries. Within the said frame, the project carries out a study of the various costs for 350 and 500-MW(e) PWR nuclear plants and derives the values to be taken for the investments, fuel, and operating and maintenance costs. The same study is done for 350 and 500-MW oil-fired plants in order to evaluate competitiveness of nuclear versus fossil power plants.
RESULTS OBTAINED
The work commences with a discussion of the role of nuclear power for developing countries, explaining the subject and motives of the project. Firstly, criteria for the economic comparison of various projects are discussed. Adequate base data and the ground rules are then selected and modified to take into consideration the conditions prevailing in the developing countries (Turkey in this specific study). Nuclear station capital costs analysis is given. The capital costs components, the factors affecting the actual cost of a given plant and breakdown of capital costs are discussed; station capital cost calculation of 350 and 500 MW(e) PWRs are obtained and discussed. Adjustments due to local conditions are also indicated. The economics of the nuclear fuel cycles of light water reactors of 3 50 and 500 MW(e) for developing countries is considered. Various steps in fuel cycles are analysed, each one with its relationship to the economic aspects involved. The cost trends of the various components of the fuel cycle have been obtained. Special emphasis is given to the calculation of transportation costs for a developing country. Computer programs have been developed for the numerical calculations. The results obtained
9 using the present-worth method (being the only acceptable one on economic grounds) are compared with the results from other simplified methods. Information and methods are presented for estimating nuclear plant operation and maintenance costs with special reference to local conditions in developing countries. The total generating cost estimates for 350 and 500-MW(e) reactor plants are calculated and discussed and the influence on cost of taxes is investigated. Estimates for total cost of turbine-generator sets for PWR-type nuclear plants under average conditions are given. The effect of unit output, location and steam conditions on the cost of turbine-generator is discussed. The effect of a one-year delay in delivery of reactor pressure vessel and steam generators is calculated. The increase in the cost of energy for such a delay is calculated. It is shown that the increase in interest during construction is the most important effect. Cost estimates for 350 and 500-MW fuel-oil-fired power plants were calculated and the influence of taxes upon costs is shown. Once more it is corroborated that the competitiveness of a nuclear power station with a fuel-oil-fired plant depends mainly on the local oil prices.
CONCLUSIONS
The study showed that it can be concluded that: (1) The estimated base price of a 350 MW(e) PWR-type nuclear power station committed in 1973 is about US $543/kW(e); if the first core is included as part of the first investment, the value is US $580/kW(e). Therefore a developing country would need about US $203 X 106 to install a nuclear plant of this size. (2) The corresponding figures for a 500-MW(e) PWR are 457.4 and US $493. 8/kW(e) including the first core, i. e. about US $247 X 106 are needed to install a 500-MW(e) nuclear plant. (3) The estimated base price of a 350 and a 500-MW fuel-oil-fired power station is 245 and US $216/kW, respectively. This is about 45-47% of the cost of a PWR-type nuclear power station. (4) Escalation cost at 7% per annum over 6 years increases the capital cost by 97. 7 and US $82. 6/kW(e) respectively for 350 and 500-MW(e) PWR power plants. Interest during construction at 8% per annum amounts to 64.8 and US $54. 8/kW(e), respectively. (5) The first core requires 37. 0 and US $36.4/kW(e) respectively for 350 and 500-MW(e) PWR power plants. (6) The cost of electric energy generated by 350 and 500-MW(e) PWR power plants of this specific study is not competitive with the cost of electric energy produced by fuel-oil-fired stations of the same size operating at 80% equivalent load factor and oil price of US $0. 47/106 Btu without taxes. The cost of energy is respectively 10.652 and 9.305 mills/kW- h for nuclear and 8. 26 and 7. 76 mills/kW- h for oil-fired stations. If the price of oil is sufficiently increased either due to taxes or higher market prices, the electric energy produced by the nuclear plants can become competitive. Other conclusions included: (a) One-year delay in delivery of the reactor pressure vessel may increase the plant investment by about 5% due to increase produced in interest
10 during construction (36%); the impact on the cost of electric energy would be in the order of 0. 40-0. 45 mills/kW • h for medium-size PWRs. (b) Transportation cost of fuel, especially the transport of irradiated fuel to distant reprocessing plants (4000-7000 miles), increases the fuel cycle cost up to 18% and might in some instances cancel the credits for Pu and U. (c) Fabrication of nuclear fuel in a developing country produces a saving of foreign exchange, but increases the cost of electric energy produced in about 0. 25 mills/kW* h due to higher fabrication cost (it increases from 90 to US $130/kg U)¿
PAPER PUBLISHED ON WORK DONE UNDER THE CONTRACT
AYBERS, N., KAKAÇ, S., BAYÜLKEN, A., GENÇAY, The Economic Comparison of Nuclear Reactors 350 and 500 MW(e) for Developing Countries, Institute for Nuclear Energy Rep. 12 (1974) pp.189.
11 RESEARCH CONTRACT No. 1027
Summary of final report IAEA-R-1079-F
TITLE
Determination of impurities in uranium plant products.
RESEARCH INSTITUTION
Analytical Institute, University of Vienna, Austria.
PRINCIPAL SCIENTIFIC INVESTIGATOR
J. Korkisch.
PERIOD OF CONTRACT
1 January 1972 - 30 June 1973.
SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT
The yellow cake produced from uranium concentrates very often contains vanadium as a main impurity together with certain amounts of molybdenum and thorium. ' Therefore the investigation of the presence of vanadium, molybdenum and thorium in the yellow cake and uranium-bearing materials is not only of purely scientific interest but also is important for the further development of the analytical procedures for their deter- mination. Methods were developed for the accurate quantitative determination of vanadium, molybdenum and thorium in samples of yellow cake and in uranium-bearing minerals.
EXPERIMENTAL METHODS
The Final Report consists of four parts describing methods developed for the accurate quantitative determination of vanadium, molybdenum and thorium in samples of yellow cake from the Mexican uranium plant at Chihuahua and in uranium-bearing minerals from the same region. For the quantitative determination of vanadium in yellow cake, a procedure has been established involving quantitative oxidation of vanadium (IV) to the pentavalent state and subsequent titration of vanadium with a standardized ferrous ammonium sulphate solution in the presence of barium diphenylamine sulphonate as indicator. For the quantitative determination of molybdenum in yellow cake, an aqueous-organic solvent mixture is used as eluent for separation of molybdenum from uranium, iron and many other elements on strongly basic anion exchanger Dowex 1, x8. For the quantitative determination of vanadium in materials of complex composition (geological samples of uranium-bearing minerals) the more rapid procedures (like the titrimetric method described in Part I of the Final Report) cannot be used. Therefore another procedure has been
12 developed for separation of vanadium by anion exchange and by determining it free from interferences employing the phosphotungstate method. When using this separation procedure molybdenum is also quantitatively separated and determined using the thiocyanate method described in Part II. For quantitative determination of small amounts of thorium in materials of high uranium contents, a method has been developed based on the separation of thorium by ion exchanger in nitrate form.
RESULTS OBTAINED
It has been shown that 10% less of the vanadium is recovered in the presence of large amounts of concentrated HCl, which is probably due to the reducing effect of hydrochloric acid. Even a 140-fold excess of Mo has no influence on the vanadium determination. Interference of the vanadium titration by chromium will be only noticeable when large amounts of Cr and very little V are present. Vanadium can be determined in uranates with high accuracy without preliminary separation from U and Mo by means of anion exchange. In 10% 6M hydrochloric acid-90% methanol solutions the elution characteristics of molybdenum show optimum values for successful separation from Fe3+ and U6+. With respect to the application of this methanol method it is shown that except for uranium, iron, cobalt and copper all other metal ions are eluted with the molybdenum. No interference is caused by vanadium, provided that its concentration does not exceed 0. 5 mg/10 ml. Copper, uranium and iron interfere most strongly, while interferences by other metal ions occur only if their concentrations exceed 0. 5 mg/ml. Much lower vanadium contents are measured in the presence of organic substances (i. e. a considerable negative error is observed). Serious interferences are observed in the presence of Ce3+, Ti4+, Zr4+, Th4+, Cr3t and Ni2+, the most serious interferences being caused by Ti4+ and Zr4+. The results of vanadium determinations in samples from Chihuahua, Mexico, show very good agreement independent of the method of their dissolution. The application of the thoronol method gives deviations of the same magnitude as when using the arsenazo III method. A good agreement between thorium values is obtained irrespective of the spectrophotometric methods used.
CONCLUSIONS
The titration method described in Part I of the Final Report is well suited for the routine determination of vanadium in yellow cake samples providing rapidity and good accuracy. The spectrophotometric determination of thorium (Part IV of the Final Report) can be performed more or less automatically and it is possible to analyse many samples simultaneously, which is of value for the routine determination of thorium.
13 RESEARCH CONTRACT No. 1027
Summary of final report IAEA-R- 1112-F
TITLE
Guide on nuclear fuel-cycle cost evaluation.
RESEARCH INSTITUTION
Electrical Industry Research Institute, Federal Electricity Commission, Mexico D. F., Mexico.
PRINCIPAL SCIENTIFIC INVESTIGATOR
R. F. Ortega C.
PERIOD OF CONTRACT
1 December 1971 - 28 February 1973
SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT
It is important for electricity utility companies in developing countries to have computational tools for evaluating the nuclear fuel-cycle costs associated with nuclear power stations being considered in their expansion plans or in the stage of bid evaluation. The difference in fuel costs can give nuclear power reactors an economic advantage over fossil-fuelled plants, for the initial capital costs are often higher in the case of nuclear reactors. The scope of the project was to study computer programs for nuclear fuel cost evaluation in current use in the USA, to simplify them, deleting those areas not relevant outside the USA, and to develop a computer program and techniques to provide quick, low-cost fuel cycle evaluations, techniques in connection with the escalation of costs and prices related to fuel cycle components, sensitivity analysis techniques, including data interpretation and plutonium recycling.
RESULTS OBTAINED
The result of the study done is a computer code named FUELCASH-II. In addition to the thermal power of the NSSS, present-worth discount rate, date for reactor start-up and reference date for present-worth calculations, the input data to FUELCASH-II code can contain some or all of the following: (1) Information on changes in the internal library of the code (optional) and net station unit heat rates at 100, 75 and 50% of net station output; (2) Information on the reactor operating regime (optional) — percentage of operating time at a given power level, plant availability factors; (3) Information on the needs of the system — net station unit heat rates or net station outputs and capacity factors as a function of time;
14 (4) Cost information — costs of materials and processes as a function of time for each type of fuel assembly (if there is only one type, this in- formation applies to all the assemblies); (5) Information on post-irradiation periods — defining the times when fuel transport and reprocessing are paid for and the times when the credits are received for final uranium and plutonium; (6) Information on pre-irradiation periods for fuel fabrication — defining the times for the series of payments and the final payment (if there is one) to cover the cost of the fuel fabrication component; (7) Information on pre-irradiation periods for natural uranium — defining the times for the series of payments and the final payment (if there is one) to cover the cost of the component corresponding to the purchase of natural uranium concentrates; (8) Information of pre-irradiation periods for enrichment — defining the times for the series of payments and the final payment (if there is one) to cover the cost of the enrichment components; (9) Information on pre-irradiation periods for the initial plutonium — defining the times for the series of payments and the final payment (if there is one) to cover the cost of the initial plutonium; (10) Information on fuel batches for all the assemblies — defining initial and final masses of uranium and plutonium, total and per-cycle unit consumption, initial and final enrichments (information on fuel loading and unloading is also included) ; (11) Information on the costs per batch for all the assemblies — defining the costs per batch of the initial and final uranium, the initial and final plutonium, fabrication, transport, reprocessing, and the initial and final fuel (information which may be received in specific offers). The output of FUELCASH-II contains: (1) For each batch: cash flow and cumulative present worth of natural uranium, conversion, enriching, fabrication, initial plutonium (if plutonium is recycled), shipping, reprocessing, uranium credit and plutonium credit; (2) Present-worth value of all payments; (3) For each batch: start and end dates for the cycle, cycle length, operation time, energy generated and present-worth value of energy; (4) Cumulative present-worth energy, total energy released, total present-worth value of energy and levelized fuel cost. The FUELCASH-II can be used in sensitivity analysis and consecutive runs can be performed for the same reactor.
15 RESEARCH CONTRACT No. 1027
Summary of final report IAEA-R-1184-F
TITLE
International intercomparison of chemical dosimeters for in-pile use.
RESEARCH INSTITUTION
Chemistry Division, Democritos Nuclear Research Center, Athens, Greece.
PRINCIPAL SCIENTIFIC INVESTIGATOR
D.G. Marketos.
PERIOD OF CONTRACT
1 July 1972 - 30 June 1973.
SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT
Measurement of energy absorption by materials from neutrons and gamma rays is a very important program for irradiation experiments. For that reason meetings on the development of calorimetric and chemical dosimeters for the determination of dose from gamma and neutron radiations have been held in Yugoslavia, France, Hungary, Czechoslovakia and Poland. The results of these meetings have indicated that calorimetric dosimeters are most suitable for intercomparison of reactor radiation and that chemical dosimeters provide the best way of measuring absorbed dose. The International Intercomparison of Reactor Calorimetric Dosimeters in Grenoble in 1970 showed that gamma radiation must be measured by calorimetric dosimeters with accuracy and reliability; however, it was recommended that the degree of accuracy could be improved by using chemical dosimeters. To provide a comparison of different types of chemical dosimeters under development, the IAEA Working Group on Reactor Radiation Measure- ments recommended that an international intercomparison of chemical dosimeters for in-pile use be held. Variables of interest include temperature, total dose, dose rate and type of radiation. All of the chemical dosimeters were intercompared under the same irradiation conditions.
EXPERIMENTAL METHODS
Since chemical dosimeters are sensitive to the gamma-ray absorbed dose, the intercomparison of chemical dosimeters was conducted at two irradiation positions having different ratios of neutron and gamma dose rates: 13 -2 1 12 2 1 Position 1: ( 16 13 2 l 12 2 1 Position 2: ($th = 2. 11 X10 n- cm -s , $fast = 3. 15 X 10 n - cm" . s" ) with 130 mR/h for gamma dose rate. The chemical measurements were supported by measurements of thermal and fast neutron flux densities and of those rates using calorimeters that had been intercompared in the Melusine reactor, during the international intercomparison of calorimeters in March 19 70 in Grenoble. Eight reactor dosimeter groups from eight Member States of the IAEA (Canada, Greece, Hungary, Poland, UK, USA and Yugoslavia) participated in the inter- comparison with eight chemical systems (fluorocarbon, cyclohexane, H2S, oxalic acid, nitrous oxide, 14CO-12CO dosimeters). Three calorimeters, one radiochromic film and nickel and gold foils were used in this chemical dosimetry intercomparison experiment. The experiment was made in the 5-MW swimming-pool type reactor (90% enriched uranium) of the Democritos Nuclear Center. The thermal and fast neutron flux intensities in the two different irradiation positions selected were determined using gold and nickel detectors. The calorimeters that had been intercompared in the Melusine reactor measuring the rate of heating in an absorber and thus providing an absolute measurement of the energy absorbed were used for calibration. RESULTS OBTAINED The comparison of the results of the chemical dosimetry measurements is much more complex than the comparison of the results of calorimetry. The results can be summarized as follows: (a) The agreement among the values from the calorimetric measure- ments in position 1 is very good, as would be expected from previous intercomparisons of calorimeters for in-pile use. The somewhat poorer agreement between the values obtained in position 2 is presumably due to the greater contributions of capture gamma rays from the aluminium spacers. (b) It seems reasonable to assign an uncertainty of ± 5% to the calorimetric value of gamma-ray absorbed dose rate in position 1. On this basis the values obtained from the chemical dosimeters agree with the calorimetry within the stated uncertainties for these dosimeters, except for cyclohexane and the VinCa aqueous oxalic acid systems. These two give values that are below the limit of the calorimetric values 14 and 21% respectively. For position 2 there is a greater range of calorimetric values and an uncertainty of ± 10% seems warranted. On this basis there is agreement between the calorimetry and the chemical dosimeters within the stated uncertainties except for cyclohexane and both áwierk and VinCa aqueous oxalic acid systems. These three give values that are below the limit of the calorimetric values by 12, 17 and 23% respectively. (c) The chemical dosimeters used in this intercomparison would appear to give the total absorbed dose rate in reactors with a maximum uncertainty of 25%. However, those dosimeters containing little or no hydrogen would appear to give the gamma-ray absorbed dose rate (in low atomic number materials) within an uncertainty of 5%. It appears that the fast neutron contributions to the absorbed dose rate can be calculated from nickel activation measurements with an uncertainty of less than 20%. 17 CONCLUSIONS The international intercomparison of reactor calorimeters in Grenoble in 19 70 showed that the gamma radiation can be measured by calorimetry and that this method is accurate and reliable. The agreement obtained here between the values for the absorbed dose rate with the different dosimeters and calorimetry measurements have been very satisfactory. However, further development of high temperature and other advanced or specialized dosimeters can be continued with confidence in the principles of the method. Further development of chemical dosimeters, ion chambers and other systems of dose measurements in reactors can be firmly based on calori- meter values. Also, further studies of the cyclohexane and oxalic acid dosimetry systems are desirable. PAPER PUBLISHED ON WORK DONE UNDER THE CONTRACT MARKETOS, D.G., BOYD, A.W., "International inteicomparison of chemical dosimeters for in-pile use", presented at Regional Conference on Radiation Protection, Jerusalem, 1973. 18 RESEARCH CONTRACT No. 1027 Summary of final report IAEA-F-1328-R TITLE Development of cultures of Thiobacillus ferrooxidans for the micro- biological leaching of sulphide and uranium ores (part of a co-ordinated program of research on the bacterial leaching of uranium ores). RESEARCH INSTITUTION Department of Microbiology, Queen Elizabeth College, University of London, London, United Kingdom. PRINCIPAL SCIENTIFIC INVESTIGATORS O.H. Tuovinen; D.P. Kelly and C.A. Jones (last two months). PERIOD OF CONTRACT 1 December 1972 - 30 November 1973. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT The application of bacterial species in processing uranium ores is still in the stage of laboratory investigation. Before its industrial application a range of problems have to be studied such as: selection of the most appropriate bacterial species with the highest yield and reproduction; the required conditions for development of bacteria cultures; the effect of organic solvents on bacterial activity; the interactions of metal ions on the bacterium. The present studies were designed t.o provide a broader understanding of the physiology of the chemolithotrophic bacterium Thiobacillus ferro- oxidans on inorganic iron and sulphur compounds, and to examine in detail the effect and interaction of metal ions on the bacterium with special reference to the development of tolerance to uranium. EXPERIMENTAL METHODS The enumeration of viable numbers of Thiobacillus ferrooxidans is made by using membrane filters on ferrous iron, thiosulphate or tetrathionate agar. Thiobacillus ferrooxidans was studied in continuous culture in constant pH 1.6, temperature 30°C, dissolved oxygen 20 mmHg, flow of carbon dioxide into the medium, and controlled flow rates giving dilution rates ranging from 0. 02 to > 1. 0 h"1. RESULTS OBTAINED The transition of iron-grown organisms to grow on tetrathionate was almost quantitative, whereas few iron-grown organisms were initially capable of growth on thiosulphate. Organisms growing on tetrathionate 19 developed equally well on thiosulphate. Thiosulphate oxidation was accompanied by tetrathionate accumulation in the medium, and continuous subculture on thiosulphate depressed Fe2+ oxidation ability.. Addition of uranyl sulphate to growing cultures caused gradual depression of Fe2+ oxidation, immediate cessation of 14CC>2 fixation and rapid loss of viability. Uranium-poisoned organisms appeared plasmolysed in electron micrographs. Metal ions, phosphate and EDTA partially alleviated uranium toxicity and the apparent frequency of mutants initially resistant to uranium was increased in the presence of high concentrations of other metals. In Warburg flasks uranyl, copper and nickel ions inhibited iron-dependent carbon dioxide fixation, the two former producing a marked uncoupling effect of CO2 fixation, similar to that caused by 2:4-dinitrophenol. Incorporation of 14C-labelled amino acids and glucose was largely dependent on the energy from Fe2+ oxidation and was strongly inhibited by uranyl ions. Little binding of isotopically labelled metals to T. ferrooxidans was observed. Kinetic analysis of the inhibition of Fe2+ oxidation by U02+indicated mixed competitive and non-competitive inhibition, and the effects of uranium were concluded to result mainly from loose binding at sites on the cell surface concerned with iron oxidation and possibly the transport of other metals. Uncoupling of CO2 fixation probably resulted in part from interference with energy metabolism and could depend on transport of UO|+ through the cell membrane. The maximum growth rate (i. e. Dcrjt.) was dependent on the level of ferrous sulphate in the culture and probably on the ferrous/ferric ratio. At very low levels of substrate it was possible to maintain steady-state cultures at dilution rates exceeding 1. 0 h"1, under which conditions most of the substrate was unoxidized but bacterial yield was relatively unaffected. Assessments were made, and from these chemostat yield data at different dilution rates, of the maintenance energy requirement and theoretical maximum yield (g dry weight of bacteria per g-atom of iron oxidized). These values indicated a relatively high maintenance requirement and Ymax similar to that calculated on wholly theoretical grounds previously. Experiments with cell suspensions demonstrated purely competitive inhibition of ferrous iron oxidation by ferric iron and kinetic data were given consistent with the Ks and K¡ values for ferrous and ferric iron obtained from the chemostat experiments. High concentrations of ferrous sulphate were found to be inhibitory to ferrous iron oxidation and may also have uncoupled carbon dioxide fixation. Furthermore, carbon dioxide fixation appeared to be more efficient under conditions of high ferrous iron oxidation rate than under conditions of lower oxidation rate (i. e. at ferrous levels around the Km). These phenomena are currently still under investigation and will be reported more fully in later work. CONCLUSIONS The results obtained from the investigations allow conditions to be set forth for the developing of the bacteria for their further industrial application. In this respect it may be inferred that: maximum growth rate (i. e. Dcrit-) depends on the level of ferrous sulphate in the culture and probably on the Fe2+/Fe3+ ratio; high concentration of ferrous sulphate inhibit ferrous oxidations; and carbon dioxide fixation is more efficient under conditions 20 of high ferrous iron oxidation rates than under conditions of lower oxidation rates, which is of essential importance for the application in processing of uranium ores. PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACT TUOVINEN, O.H., KELLY, D.P., Studies on the growth of Thiobacillus ferrooxidans. II. Toxicity of uranium to growing cultures and tolerance conferred by mutation, other metal ions, potassium phosphate and EDTA, Arch. Mikrobiol. (in press). TUOVINEN, O.H., KELLY, D.P., Studies on the growth of Thiobacillus ferrooxidans. III. Influence of uranium, other metal ions and 2:4-dinitrophenol on ferrous iron oxidation and carbon dioxide fixation by cell suspensions, Arch. Mikrobiol. (in press). TUOVINEN, O.H., KELLY, D.P., Use of microorganisms for the recovery of metals, Int. Metall. Rev. (in press). 21 WASTE MANAGEMENT RESEARCH CONTRACT No. 1213 Summary of final report IAEA-R-1213-F TITLE Calculations on and building of mathematical models of processes involved in the deposition of wastes in water. RESEARCH INSTITUTION Department of Mathematics, Twente University of Technology, Enschede, The Netherlands. PRINCIPAL SCIENTIFIC INVESTIGATOR I. W. van Spiegel. PERIOD OF CONTRACT 1 September 1972 - 31 August 1973 SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT The deposition of wastes in the sea has become of worldwide interest as a result of man's concern with the pollution of the environment. An understanding of the processes involved in the diffusion and sedimentation of this material in the sea is essential for satisfactory control of the disposal of these wastes. Models that describe the turbulent diffusion of sedimenting radioactive material in seawater are equally applicable to other wastes discharged to the sea. The aim of this research was to construct a universal model by which forecasts of the effects of various waste disposals could be made. A further aim was the investigation of the sensitivity of a model describing diffusion, sedimentation and radioactive decay in seawater to changes in the description of the diffusion process. EXPERIMENTAL METHODS A major part of the investigation was the modelling of the various phenomena that occur next to diffusion, sedimentation and decay, especially those concerning the reaction of biota to radioactive waste. The following aspects were taken into account: compartmental models, growth of biomass, birth-death equilibrium, grazing and combinations of these. All aspects were present in the description of the experimental work of Miettinen et al. The investigation of the sensibility of a model describing diffusion in seawater was done by partly analytical and partly numerical evaluation of various integrals whose integrands corresponded to the various solutions proposed for turbulent diffusion in seawater. 23 'RESULTS OBTAINED The main results are the following: (1) The fast reproduction of plankton can indeed account for the decrease in the concentration of waste in this specimen of biomass; (2) The combination of growth and compartmental description of a biomass explains why young animals are bound to be more contaminated than older ones, this being one of the questions often raised in this field; (3) The diffusion model constants occurring in the various proposed solutions, as given in the literature, turn out to be inconsistent when one specific process is described. When these model constants are relatively gauged the qualitative differences in the description are minor ones. For the éxperimenter two points should be stressed, viz. the re-examination of the experimental values of the model constants and the measurement of the constant describing sedimentation are of great importance in order to make predictions on the distribution of radioactive waste by means of diffusion. Once these constants are known there are no further difficulties in the application of the theory. PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACT HOEDE, C., OUDEN, den A.C.B., ROUHOF, G.J.S., TWILT, F., "On the use of models in sea research", Memorandum Nr. 39, Department of Applied Mathematics, Twente University of Technology (1973). OUDEN, den A.C.B., "A numerical comparison of various mechanisms proposed for diffusion in sea water", Memorandum Nr. 43, Department of Applied Mathematics, Twente University of Technology (1973). 24 PHYSICS AND CHEMISTRY RESEARCH CONTRACT No. 818 Summary of final report IAEA-R-818-F TITLE Radio-spectroscopic investigation: the ordering of magnetics containing isotopes 57Fe. RESEARCH INSTITUTION Institute of Crystallography of the USSR Academy of Sciences, Moscow, USSR. PRINCIPAL SCIENTIFIC INVESTIGATOR A. V. Zalesky. PERIOD OF CONTRACT 1 November 1969 - 30 June 1973. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT Ferromagnetic materials have many important practical applications and yet are still not well understood scientifically. A fundamental description of magnetized solids involves the precise and fine-grained knowledge of the spatial distributions of the electron and spin densities in the material. The nuclei of ferromagnetic materials that possess magnetic moments can be used as point probes for the application of nuclear magnetic resonance (NMR) techniques for the measurement of the local magnetic fields produced by the electrons. The part of the field due to the electrons belonging to the nucleus itself is called the hyperfine field and for ferro- magnetic substances this is usually the dominant part of the local field. In the present work NMR is studied in the ferromagnetic atoms of 57Fe, which occurs with a natural abundance in iron of about 2% and which is the only naturally occurring iron isotope with a magnetic moment and NMR response. The macroscopic behaviour of ferromagnetic materials is largely determined by the domain structure, which arises spontaneously in most cases, as a subdivision of (even a single crystal of) the material into a number of small volumes (called domains), each characterized by a saturated, monodirectional magnetization, but with adjoining domain magnetizations usually oriented in opposite (180°) directions so as to lower the total energy of the crystal. The thin planar regions between domains are called the domain walls and since their existence depends on a fine balance between the various interactions and quantum conditions in the 25 crystal, the domain walls, in contrast to the bulk of the domain, are quite responsive to external magnetic fields. The walls are rather easily moved and can be made to oscillate. EXPERIMENTAL METHODS The apparatus required for performing NMR measurements in ferromagnetic materials differs from usual NMR instruments. In ferro- magnetic materials (below the Curie temperature) the local fields at the resonating nuclei are usually much larger than any external field that can be applied. Domain structure also leads to a strong inhomogeneity in the magnetization in the material, which is, in addition, temperature dependent. Moreover, the NMR signal is also relatively very weak. A spectrometer with high sensitivity and a broad frequency range is therefore required. Except during the early stages, most of the present work was performed with a Nuclear Quadrupole Resonance spectrometer, manufactured by DECCA RADAR, Ltd., and provided by the IAEA as part of the research contract. The pioneering work on NMR in ferromagnetics was reported in 19 59 by Gossard and Portis, shortly before the discovery of the Mössbauer effect. The Mössbauer effect then provided a powerful and convenient technique for the study of the hyperfine field in ferromagnetics, thanks to the properties of 57Fe. But it had also been pointed out by Muller and Sher (1962) that domain structures in ferromagnetics could be studied by NMR techniques if a steady magnetic field is applied in a direction parallel to the domain walls and perpendicular to the easy direction of magnetization. The present work was primarily an attempt to develop the proper apparatus and samples to observe NMR signals caused by nuclei in domain walls of ferromagnetic single crystals. RESULTS OBTAINED NMR signals were successfully observed from a number of mono- crystals of weak ferromagnetic oxides, including both ortho- and hexagonal ferrites: o-Fe203, Y Fe03, DyFe03, ErFe03, BaFe12019, and BaFe18027. For hematite (o,-Fe203) only one NMR line is observed, which is theoretically interpreted as arising from the fact that in this material the NMR frequencies for nuclei in the domains and in the domain walls are almost the same (due to the small anisotropy of magnetization). For the other materials, either one line at the frequency expected for the domain or two lines (at domain and wall frequencies) were observed. The theoretically predicted dependence of the NMR frequencies on a d. c. magnetic field applied in the way suggested by Muller and Sher, i. e. linear dependence for the case of absorption by nuclei in the centre of the domain walls, quadratic, for absorption in the edge of the walls, enabled interpretations to be made in a number of cases. For BaFe^Oig the resonating nuclei would appear to be in the edge of the walls. Further information could be obtained from observing the temperature dependence of the NMR frequencies; in the present work observed in the range 77 to 300°K. Theoretically it is expected that 'in-wall' thermal excitations can lead to different temperature dependences of the local magnetization, and hence to different temperature dependences of the NMR 26 frequencies for domains and for walls. Theory predicts that the difference A between the two NMR frequencies should depend on the absolute temperature: A = A(T = 0) + (constant)XT. The measurements agree with this in the range studied.' CONCLUSIONS It has been successfully demonstrated that weak ferromagnetic oxides can be studied by NMR techniques. In particular it seems possible to obtain unique information on the nature of the spin orientation in domain boundaries if NMR spectra are measured with the sample in an external field. It was also shown that the hysteresis properties resulting from the domain structure can be studied by NMR measurements. PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACT ZALESSKU, A.v., Prib. Tekh. Ehksp. 2 (1970) 156. ZALESSKU, A.V., CHUDAKOV, V.S., Kristallografiya 15 (1970) 299. ZALESSKIJ, A.V., ZHELUDEV, I.S., VOSKANYAN, R.A., Zh. Ehksp. Teor. Fiz., Pis'maRed. 9 4 (1969) 242. ZALESSKU, A.V., Trudi Yubilejnoj Konferentsii po Paramagnitnomu Rezonansu, Kazan (1970). ZALESSKU, A.V., ZHELUDEV, I.S., VOSKANYAN, R.A., Zh. Ehksp. Teor. Fiz. 59 9 (1970). ZALESSKU, A. V., Zh. Ehksp. Teor. Fiz., Pis'ma Red. 12 (1970) 468. ZALESSKU, A.V., LOBACHEV, A.N., DEM'YANETS, L.D., IVASHCHENKO, A.N., MEL'NIKOV, O.K., LEBEDEVA, T.G., Zh. Ehksp. Teor. Fiz. jU. 6(12) (1971) 2337. ZALESSKU, A.V., Fiz. Tverd. Tela 15 2 (1973) 624. ZALESSKU, A.V., SAVVINOV, A.M., ZHELUDEV, I.S., IVASHCHENKO, A.N., Fiz. Tverd. Tela 15 3 (1973) 903. ZALESSKU, A.V., SAVVINOV, A.M., ZHELUDEV, I.S., LOBACHEV, A.N., IVASHCHENKO, A.N., MEL'NIKOV, O.K., Tezisy Mezhdunarodnoj Konferentsii po Magnetizmu, Moscow (1973). 27 RESEARCH CONTRACT No. 1027 Summary of final report IAEA-R-844-F TITLE Nuclear and hyperfine interaction measurements by angular correlation and Mössbauer technique. RESEARCH INSTITUTION Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil. PRINCIPAL SCIENTIFIC INVESTIGATOR P. da R. Andrade; later F.C. Zawislak. PERIOD OF CONTRACT 1 December 1969 - 30 November 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT Angular correlation techniques have long been used in nuclear spectrometry for the study of nuclear structure. When two gamma rays, for instance, are emitted sequentially by a nucleus, there will in general be a correlation between the two directions, or angles, of emission, which depends on the total angular momentum in the initial, intermediate and final nuclear states involved in the cascade of radiation. Measurement of the angular distributions of the cascade radiations also gives direct information on the multipole character (angular momentum) of the emitted radiation field. In the case of mixed-multipole transitions interference terms affect the angular distributions and permit the determination of the relative amplitudes of the different multipole contributions. Angular correlations are affected by extranuclear electromagnetic fields, and if the field is strong enough and the intermediate state involved lives long enough, the reorientation in space produced can alter the observed angular correlation. This may be used to study unknown nuclear electromagnetic moments (magnetic dipole or electric quadrupole, usually) in a known field, or unknown extranuclear fields with an intermediate state with a known electromagnetic moment. The method of perturbed angular correlations (PAC) can thus be used either to determine nuclear parameters or to study in a localized-way strong electromagnetic fields existing in molecules or in solid (or liquid) state studies. The Mössbauer effect, which takes advantage of 'recoilless' emission and absorption of gamma rays, which can be effected under certain conditions with certain nuclear isotopes, permits very precise measure- ments of small differences in energies and can therefore be used to study the small shifts in nuclear energy levels caused by the nuclear hyperfine interactions. 28 EXPERIMENTAL METHODS Considerable effort was devoted to building up the laboratory facilities to enable PAC and ME measurements for research in nuclear and solid- state physics. Three automated and computer-interforced angular correlation tables and two ME electromechanical drives were constructed. A fast coincidence system was developed for fast-timing with very low-energy gamma rays; a resolution of 5 X 10-9 s for the 122 - 14. 4 keV cascade in 57Fe was achieved. A number of ovens and temperature control devices were constructed. RESULTS OBTAINED Various isotopes have been investigated using the gamma-gamma and conversion electron-gamma angular correlation techniques. Properties of nuclear states (spins, parities, lifetimes and magnetic moments) and transitions (multipolarities, particle parameters) have been studied experimentally and theoretically. The perturbed angular correlation (PAC) technique has been applied successfully to study nuclear hyperfine interactions (magnetic and electric) in solids. Internal magnetic fields acting on radioactive impurities in ferromagnetic compounds and alloys were studied as a function of temperature, composition and location in the lattice. Electric field gradients in a series of Hf compounds have also been studied. Mössbauer studies in this Institute have been done using only low- energy transitions since the Institute did not obtain liquid helium facilities until the end of 1972. Nuclear quadrupole interactions, magnetic hyperfine interactions and isomeric shifts have been measured in various systems and compounds using the Mössbauer spectroscopy with 57Fe, 129I and 119Sn nuclei. CONCLUSIONS It is clear that these relatively inexpensive techniques permit a wide range of important research to be undertaken, particularly in the study of condensed matter. This research has also proved to be highly effective for training research workers. PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACT 1. Nuclear structure studies MACIEL, Alice, Measurement and Interpretation of Nuclear Properties in 95Mo, u5In and 131Cs, PhD thesis, 1970. LIVI, F.P. , Measurement of the Magnetic Moment of a Two Quasi-particle State in 182W, MSc thesis, 1970. LIVI, R.P., ZAWISLAK, F.C., Cienc. Cult. 23 (1971) 28. JORNADA, Edna H., Non-perturbed and Perturbed Triple Gamma-gamma-gamma Directional Angular Correlations, MSc thesis, 1972. VASQUEZ, A., Nuclear Spectroscopy study in 131Cs, to be published in Nucl. Phys. ZAWISLAK, F.C., RODGERS, J.D., MENESES, E.A., Conversion of electron-gamma and gamma-gamma directional angular correlations in 160Dy, submitted to Nucl. Phys. 29 2. Nuclear hyperfine interaction studies VASQUEZ, A., Nuclear Quadrupole Interactions in 57Fe by Gamma-gamma Angular Correlations, MSc thesis, 1970. ANDRADE, P. da R. , VASOUEZ, A., RODGERS, J.D. , Phys. Rev. B1 (1970) 2912, BRANDÄO, D.E., Study of the Hyperfine Magnetic Field on Mo in Fe as a Function of Temperature, PhD thesis, 1971. KUNZLER, J., Nuclear Quadrupole Interactions in Ferroelectric lalHf Compounds, MSc thesis, 1971. LIVI, R.P., Study of the Hyperfine Magnetic Interaction Acting on Nuclei of 181Ta in a Ni Matrix, using the Differential PAC Method, MSc thesis, 1971. ANDRADE, P. da R., FORKER, M., RODGERS, J.D., KUNZLER, J., Phys. Rev. B6 (1972) 2560. ANDRADE, P. da R., RODGERS, J.D., Rev. Bras. Fis. 1 (1971) 37. FORKER, M., RODGERS, J.D.,' Nucl. Instrum. Meth. 96 (1971) 453. SCHAF, J., Study of the Hyperfine Magnetic Interaction on 207Pb in a Fe Matrix as a Function of Temperature, MSc thesis, 1972. SCHAF, J., ZAWISLAK, F.C., Rev. Bras. Fis, (in press). LIVI, R.P., LIVI, F.P., RODGERS, J.D., ZAWISLAK, F.C., Study of the hyperfine magnetic field on 181Ta in Ni matrix, submitted to Phys. Rev. SCHAF, J., FRAGA, Z.J., PAC study of the magnetic Cu2MnBi Heusler alloy, submitted to Phys. Lett. MÜNDT, W., Frozen Solutions of Sodium Nitroprusside by Mössbauer Technique, MSc thesis, 1970. KUNRATH, I., Study of Natural Iron Minerals using the Mössbauer Technique, MSc thesis, 1970. COSTA, M.I., Jr., Interpretation of Unresolved Mössbauer Spectra in 1Z9I Compounds, MSc thesis, 1971. COSTA, M.I., Jr., ANDRADE, P. da R., VICCARO, P.J., Rev. Bras. Fis. 1 (1971) 337. 30 RESEARCH CONTRACT No. 1027 Summary of final report IAEA-R-895-F TITLE Chemical behaviour of radionuclides in natural waters, and their interaction with chelating agents. RESEARCH INSTITUTION G. Ciamician Chemical Institute, University of Bologna, Italy. PRINCIPAL SCIENTIFIC INVESTIGATOR R. Muzzarelli. PERIOD OF CONTRACT 15 March 1970 - 14 May 1973. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT This project was initiated to study the application of the naturally occurring chelating agents chitin and chitosan to the concentration of trace quantities of radionuclides from seawater or freshwater. Previous work by the principal investigator had shown that chitosan could be used to collect trace amounts of transition metals with no appreciable interference from sodium, calcium or magnesium. The scope of the project was to include the study of the chemical forms assumed by radioelements present or released into waters, the determination of the optimum conditions for collection on chitin and chitosan, the selection of suitable reagents for the elution of the collected radioelements from the columns, and other studies to lead to automatic analysis of water for radioelements by chromatography on chitin or chitosan. EXPERIMENTAL METHODS This research involved the use of normal chromatographic procedures for concentration of trace elements. Various analytical methods to determine quantitatively the materials separated have been used, including atomic absorption spectrophotometry. Radiochemical techniques, including gamma-ray spectrometry, gas flow counting and radiochromatographic scanning, have been used together with optical and electrochemical techniques and X-ray diffraction. RESULTS OBTAINED Selective collection of metal ions by chitosan has been extensively studied. It was found that ions such as Na(I), K(I) and Mg(II) are not collected, while others, mainly of transition metals, are collected to a 31 larger extent. The influence of temperature, particle size of the chitosan, and competition of two ions towards collection have been studied. The pretreatment of chitosan resin with silver ion showed it to be useful for collection of traces of cyanide ion from ammonium salt brines and seawater. Similarly, chitosan molybdate was found to be effective in selectively concentrating phosphate. Other studies have shown chitin and chitosan to be suitable for the rapid separation of fission products from caesium in nitric acid solutions or irradiated fuel. In this connection, chitin, chitosan and their derivatives have been shown to be resistant to radiation to a sufficient degree to be useful for concentrating and retaining radioactive trace materials. CONCLUSIONS Chitin and chitosan resins have selective chelating properties that can prove useful for a variety of purposes including concentration of select radionuclides, concentration of trace elements and, with modification, concentration of trace anions such as phosphate. These resins would appear, because they are naturally occurring, to be economic to obtain and to provide promise of practical applications in analytical chemistry, process chemistry for removal of trace metals, and in environmental pollution studies. 32 RESEARCH CONTRACT No. 1027 Summary of final report IAEA-R-1141-F TITLE Development and industrial application of a high sensitivity Mössbauer spectrometer. RESEARCH INSTITUTION Department of Atomic Physics, Physical Faculty, Kliment Ohridski University of Sofia, Bulgaria. PRINCIPAL SCIENTIFIC INVESTIGATOR T. Bonchev. PERIOD OF CONTRACT 15 January 1972 - 28 February 1973. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT In recent years Mössbauer spectroscopy has developed extremely rapidly as a research tool applicable in many different fields of science and technology. At the same time the instrumentation has improved to a high level, leaving only little room for further betterment. There are, nevertheless, two possible and desirable trends for improvement in Mössbauer spectrometers: (1) the sensitivity of Mössbauer radiation detectors can be increased, thus enabling experiments with small quantities of Mössbauer isotopes; (2) simple, reliable and inexpensive (also portable) spectrometers should be designed to be used in routine measurements in industry or in the field. In the frame of the present contract, some of the outstanding experi- mental problems were approached and some useful results were obtained. It was shown how the improved experimental methods can influence the statistical reliability of the spectra measurements or can considerably shorten the necessary measuring time. EXPERIMENTAL METHODS AND RESULTS OBTAINED The resonance detectors widely used in Mössbauer spectroscopy were applied in the present series of experiments in a new manner: the investigated substance was suspended in the matrix of the scintillator, which was made thinner than the mean free path of conversion electrons. Compared with the established methods, the Mössbauer spectrum of a considerably smaller amount can be registered by this technique, which could become particularly useful in microanalysis. A sensitivity limit of the order of 10"5 mg/cm2 was reached, representing an improvement of 33 two orders of magnitude over the methods used at present. Numerous experiments with tin and iron as Mössbauer isotopes confirmed the high sensitivity of the method. The principle of a resonance sample detector was applied in a modified version to the studies of surface phenomena. The surface under investigation was covered with a thin layer of a plastic scintillator and was connected to the photomultiplier by means of a Perspex light conductor. There are two main advantages of using such a detector configuration compared with the usually employed gas-discharge detectors: its simplicity and the possibility to cool the sample together with the detector. The method was successfully tested in several experiments. An ionization chamber should be a suitable detector for routine measurements of Mössbauer spectra. Two types of such detectors were tested: a scintillation and a resonance ionization chamber and the comparison showed the advantages and limitations of spectrometry employing these detectors. With the use of ionization chambers the measuring time is considerably reduced; they also permit a simplification of the attached electronics, possess a high resistance to mechanical mishandling and have practically an infinite lifetime. These features indicated their strong potential applicability in standardized,perhaps portable Mössbauer spectro- meters. A first effort to prove the practical feasibility of Mössbauer autoradio- graphy yielded some optimistic preliminary results. 34 RADIOISOTOPES AND RADIATION APPLICATIONS AGRICULTURE FOOD TECHNOLOGY INDUSTRY MEDICINE DOSIMETRY HYDROLOGY AGRICULTURE RESEARCH AGREEMENT No. 418 Summary of final report IAEA-R-418-F TITLE The use of isotopes and radiation in studies on etiology, effects and treatment of parasitic diseases in domestic animals (part of a co-ordinated program). RESEARCH INSTITUTION University of Glasgow Veterinary School, and The Wellcome Laboratories for Experimental Parasitology, Glasgow, UK. PRINCIPAL SCIENTIFIC INVESTIGATOR W. Mulligan. PERIOD OF AGREEMENT 1 August 1966 - 28 February 1973. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT Nearly all domestic animals are parasitized to some extent at some stage of their lives. This applies both to the developed and to the developing countries. The problem is likely to become aggravated as standards are raised in developing countries because of the increased density of stocking, which will inevitably take place on improved pastures. The pathogenic effect of many of these worms is severe and may take the form of: (i) loss of nutrients from the body (iron, protein, etc.); (ii) prevention of absorption of nutrients from the intestine; and (iii) secondary effects of loss of nutrients, anaemia, hypoproteinaemia, etc. In many cases the position is further complicated by already existing nutritional déficiences. The world importance of the various parasites is summarized in the IAEA Technical Reports Series No. 3. Apart from Glasgow, most of the work on radiation attenuation of helminth larvae, with a view to vaccine production, has been carried out in Yugoslavia at the Institute for the Application of Nuclear Energy in Agri- culture, Veterinary Medicine and Forestry, Zemun. Workers there have developed a satisfactory vaccine against sheep lungworm. The possibility of applying such methods to immunization against Schistosoma has been the subject of extensive study of the Department of Medical Zoology, Walter Reed Army Institute of Research, Washington. The successful application of radiation attenuation to the production of an antihelminth vaccine was carried out by the Glasgow workers, and as a 37 result of this work a vaccine against the cattle lungworm is now being widely used in the UK and a number of other European countries. A successful vaccine against hookworm in the dog is soon to be marketed, and successful vaccination against a number of important gastro-intestinal parasites of sheep has-been effected in adult animals. Over the years tracer techniques have been applied to the effects of certain parasites. EXPERIMENTAL METHODS Plasma albumin was labelled with either 131I or 125I, plasma proteins with 51Cr or 95Nb, and red cells with either 59Fe or 51Cr. For detailed methods, please refer to published papers. RESULTS OBTAINED AND CONCLUSIONS The specific host/parasite systems studied were Fasciola hepatica in sheep and rabbits, Ostertagia circumcinta in sheep, Nippostrongylus brasi- liensis in rats and latterly, Schistosoma mattheei in sheep. 1. Fasciola hepatica in sheep and rabbits The hypoproteinaemia in animals suffering from fascioliasis was shown to be associated with an increased catabolic rate of albumin. Experiments with 131I-labelled albumin showed that rabbits infected with 180 metacercariae 8-9 weeks prior to measurements had albumin half-lives of 83 h compared to 211 h in controls. This was due largely to abnormally high losses of plasma protein into the gastro-intestinal tract, possibly via bile, because the faecal excretion of labelled polyvinylpyrrolidone was higher in infected rabbits. 51Cr-labelled red cells were used to study the anaemia in animals infected with Fasciola hepatica. Infection shortened the half-life of red cells and increased faecal radioactivity. The picture was consistent with a loss of red cells into the gut via flukes and bile. In experiments where albumin was labelled with 95Nb and the red cells with 51Cr, it was shown that the loss of plasma protein was greater than could be accounted for by the loss of whole blood. The histological picture in the bile ducts is consistent with the view that there is additional loss of plasma proteinthere without concommitant losses of red cells. Only in very severe infections with Fasciola hepatica has any impairment of the formation of red cells or plasma protein synthesis been noted. In many experimental infections the rate of removal of 59Fe from plasma and protein synthesis was greater than that in control animals. Other experiments followed the changes in plasma protein and red cell turnover during a ten-week period following infection. It was suggested that the blood loss suffered by the host is determined not only by the number of parasites present within its bile ducts, but also by their size and nutritional requirements. 2. Ostertagia circumcinta in sheep 1251-albumin and 51CrCl3 were used to measure plasma albumin turnover rates and plasma loss into the gastro-intestinal tract for five weeks following infection of sheep with 300 000-900 000 Ostertagia circumcinta larvae. Diar- rhoea and inappetence occurred only with the heavier infections and were 38 transient. A marked rise in plasma loss and plasma pepsinogen values occurred between days 5 and 9 and these were associated with a large increase in the turnover rate of albumin. The plasma leakage and the albumin hypercatabolism decreased between days 14 and 22 but plasma pepsinogen values remained elevated. Serum albumin concentrations were not greatly affected by the infection. In other experiments where the body water turnover and water balance in infected animals was compared with pair fed controls it was concluded that the reduction in body water turnover observed in the infected animals was principally due to the anorexia induced by the parasitic infection. 3. Nippostrongylus brasiliensis in rats This host-parasite model system was used to study some aspects of the immune reaction to gastro-intestinal helminths. The uptake of 32P-labelled inorganic phosphate and 75Se-labelled seleno-methionine fromthe host's tissue fluids was measured at different stages of infection. It was found that the uptake declined rapidly from day 7 of the infection onward. While worms showing lowered uptake were able to ' recover' when transferred surgically to a fresh rat, the extent of recovery depended on the length of time they had been in the original host. It appears that there is a significant interference in the parasites' metabolism several days before expulsion. 4. Schistosoma mattheei in sheep Following infection with 10 000 cercariae, reduced urine volume and mild anaemia were detected in parasitized animals 4 to 5 weeks following infection. Marked changes occurred over a 6-week period following ovi- position, i.e. between about 6 and 12 weeks after infection. All infected animals developed anaemia (normocytic and normochronic); hyperproteinaemia due mainly to increased gamma globulin levels, and hypoalbuminaemia were also constant features. In severely affected cases, macrocytic anaemia and hypoproteinaemia were detected terminally. Eight weeks after infection there was a pronounced expansion of plasma and blood volumes and a lowering of circulating red cell volume. The retention of water and sodium was to some extent responsible for the initial rise in plasma volume in parasitized animals but a marked terminal dehydra- tion was evident. PAPERS PUBLISHED ON WORK DONE UNDER THE AGREEMENT DARGIE, J.D., MULLIGAN, W., The onset and development of anaemia and hypoalbuminaemia in rabbits infected with Fasciola hepatica, J. Comp. Path. 81 (1971) 187. HENNEY, R. W., MACLEAN, I.M., MULLIGAN, W., Changes in the metabolism of Nippostrongylus brasiliensis associated with the development of host immunity, J. Physiol. 217 (1971) 57. HOIMES, P. H. , BREMMER, K. C., The pathophysiology of ovine ostertagiasis: Water balance and turnover studies, Res. Vet. Sei. 12 (1971) 381. HOIMES, P. H., MACLEAN, J.M., The pathophysiology of ovine ostertagiasis : a study of the changes in plasma protein metabolism following single infections, Res. Vet. Sei. 12 (1971) 265. 39 FITZPATRICK, B. , MULLIGAN, W., "Variables in the radiation-attenuation of helminth larvae: temperature/ oxygen effects", Isotopes and Radiation in Parasitology (Proc. Research Co-oidination Meeting Vienna, 1967), IAEA, Vienna (1968) 17. URQUHART, G.M., "Immune response of young animals to infection with X-irradiated and normal nematode larvae", Isotopes and Radiation in Parasitology (Proc. Research Co-ordination Meeting Vienna, 1967), IAEA, Vienna (1968) 35. MACLEAN, J.M., HOLMES, P.H., DARGIE, J. D., MULLIGAN, W., "Pathophysiology of Fasciola hepatica infections", Isotopes and Radiation in Parasitology (Proc. Research Co-ordination Meeting Vienna, 1967), IAEA, Vienna (1968) 117. URQUHART, G.M., JARRETT, Ellen E. E., "Relationship of age to the immune response in helminth infections", Isotopes and Radiation in Parasitology II (Ptoc. Research Co-oidination Meeting Vienna, 1969), IAEA, Vienna (1970) 1. DARGIE, I.D., HOLMES, P. H., MACLEAN, J.M., MULLIGAN, W., "Pathophysiology of Fasciola hepatica infections", Isotopes and Radiation in Parasitology II (Proc. Research Co-ordination Meeting Vienna, 1969), IAEA, Vienna (1970) 45. HENNEY, R. W., MACLEAN, J.M., MULLIGAN, W., "Isotopic methods in the study of immunity to gastro- intestinal helminths", Isotopes and Radiation in Parasitology III (Proc. Research Co-ordination Meeting Kenya, 1971), IAEA, Vienna (1973) 3. CUNNINGHAM, M.P., BROWN, C. G. D., PURNELL, R.E., MUSOKE, A.J., BURRIDGE, M.J.. DARGIE, J. D. . "Some effects of irradiation on the infective stage of Theileria parva harvested from infected ticks", Isotopes and Radiation in Parasitology III (Proc. Research Co-ordination Meeting Kenya, 1971), IAEA, Vienna (1973) 145. MULLIGAN, W., The effect of helminthic infection on the protein metabolism of the host, Pioc. Nuti. Soc. 31 (1972) 47. MULLIGAN, W., CUPERLOVIC, K., BOROJEVIC, D., LALIC, R., The biological labelling with "Se of protein antigens of Fasciola hepatica, Immunology 23 (1972) 957. PRESTON, J.M., DARGIE, J.D., MACLEAN, J.M., Pathophysiology of ovine schistosomiasis, J. Comp. Path. 83 (1973). 40 RESEARCH AGREEMENT No. 507 Summary of final report IAEA-R-507-F TITLE The use of radioisotopes as reference substances in studies of intestinal absorption and digestibility (part of a co-ordinated program of research on the use of isotopes and radiation in studies on etiology, effects and control of parasitic diseases in domestic animals). RESEARCH INSTITUTION Department of Animal Science, The Volcani Institute of Agricultural Research, Rehovoth, Israel. PRINCIPAL SCIENTIFIC INVESTIGATOR S. Hurwitz. PERIOD OF AGREEMENT 1 February 1967 - 29 February 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT Helminth infections lower production of animals partly by reducing food intake and partly by decreasing the efficiency of utilization. The latter effect may be mediated by interfering with the normal processes of digestion and absorption of nutrients, and the metabolism of the absorbed nutrients. Net effects on the digestion and absorption processes can be studied using inert, non-absorbable gastro-intestinal markers, many of which can be radioactive and thus easily measured. 91Y was the reference marker used in these studies of protein and electrolyte absorption in chicks infected with Ascaridia galli. EXPERIMENTAL METHODS Male white Leghorn chicks, 7 days old, were infected with larvated ova of Ascardia galli by crop intubation. After four weeks the experimental diet (all vegetable, with soybean meal as the main source of protein and containing 70 yCi/kg of 91Y) was fed for 5 days. The chicks were killed, the intestine was immediately removed and separated into duodenum, upper and lower jejunum and upper and lower ileum, and the contents emptied into plaster beakers standing in crushed ice to minimize in vitro digestion of protein. The time between killing the chicks and emptying the segments was kept to less than 3 minutes and no apparent peeling of the intestinal mucosa occurred. 41 RESULTS OBTAINED The mean body weight of the uninfected chicks was significantly higher than that of the affected ones (577 versus 531); infected birds carried between 0 and 30 parasites and only those carrying more than 10 were used in the absorption analysis. Parasites were concentrated mainly in the first half of the jejunum, although they were often present in the second half and, more rarely, in the upper ileum. In control birds most of the protein digestion had occurred at the level of the duodenum; absorption occurred mainly posterior to the duodenum. In infected birds there was a net secretion of nitrogen anterior to the duodenum. However, at the lower ileum the apparent percentage of digestion and absorption was similar for both the infected and uninfected groups. For phosphate there was a net secretion in infected birds up to the duodenum but posterior to this their absorption was higher. Overall, the absorption of phosphate was higher in infected than in uninfected birds. The effect of the parasite on protein digestion and absorption may be associated with reduced chymotrypsin activity. It is suggested that at higher levels of infection, similar to those that occur naturally, the effects noted in these experiments may be more severe, particularly during the larval stages of the parasite. Furthermore, the compensations in absorption observed in these studies may not offset the increased secretions occurring anterior to the duodenum. CONCLUSIONS Infection with A. galli is associated with differential effects on the sites of digestion and absorption in chicks. At low levels of infection increases in the secretion of nitrogen and phosphate anterior to the duodenum are compensated for by increased absorptions posterior so that there is no overall net effect, and in the case of phosphate there may even be a higher net absorption in infected birds. PAPERS PUBLISHED ON WORK DONE UNDER THE AGREEMENT HURWITZ, S., "Use of labelled reference substances in studies of intestinal absorption and digestibility", Isotopes and Radiation in Parasitology (Proc. Research Co-ordination Meeting Vienna, 1967), IAEA, Vienna (1968) 141. HURWITZ, S., "Reference substances to measure intestinal absorption in the presence of helminthic infections", Isotopes and Radiation in Parasitology n (Proc. Research Co-oidination Meeting Vienna, 1969), IAEA, Vienna (1970) 77. HURWITZ, S., "Effect of Ascaridia galli on protein and electrolyte absorption from chicken intestines". Isotopes and Radiation in Parasitology III (Proc. Research Co-ordination Meeting Kabete, 1971), IAEA, Vienne (1973) 61. 42 RESEARCH AGREEMENT No. 507 Summary of final report IAEA-R-507-F TITLE Physiology of nutrition of Hypoderma-larvae in comparison with facul- tative and obligate parasitic fly-larvae (part of co-ordinated program on the control of animal insect pests by the sterile-male technique). RESEARCH INSTITUTION Institut für Angewandte Zoologie der Universität Bonn, Federal Republic of Germany. PRINCIPAL SCIENTIFIC INVESTIGATOR W. Kloft. PERIOD OF CONTRACT 1 April- 28 February 1973. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT To consider the sterile-male technique for control of Hypoderma a method of rearing must be developed. This research was aimed at devising this and also at studying the physiology of Callitroga spp. EXPERIMENTAL METHODS The usual biochemical and physiological methods were used. RESULTS AND CONCLUSIONS The oxygen consumption of 3 stages of parasitic larvae and 2 stages of prepupae of the 3 Calliphoridae (Callitroga macellaria (Fabricius), Lucilia cuprina (Wiedemann) and Calliphora vicina Rob. Desvoidy) was determined at various temperatures: Callitroga 17-47°C at 5 degC intervals; Lucilia 15, 30, 35°C and Calliphora 10-33°C (Warburg method). In general the reaction to changes of temperature is more intensive in parasitic than in prepupae stages. The metabolic rate of cold-adapted stages is relatively high compared with the warm-adapted ones at a definite temperature. In general the oxygen consumption decreases during development at a definite temperature. The respiration during the course of the experiment was examined by comparing the oxygen consumption of the first and second part of the experi- ment and by a regression analysis. The results are explained as regulatory 43 processes reflecting the different temperature adaptation of parasitic and non-parasitic stages of Callitroga, the species corresponding to the diverse temperature of their environment. PAPERS PUBLISHED ON WORK DONE UNDER THE A GR EE WIE NT MEYER, S.G. E., SCHAUB, G. , "Larval development of Calliphoridae: Adaptation and control", presented at Symp. Effects of Temperature on Heterothermic Organisms - Ecology and Mechanisms, Obergurgl, Austria, Sep. 1972. MEYER, S. G. E., SCHAUB, G., The respiratory metabolism of Calliphoridae larvae in relation to temperature adaptation and contiol (in German), 3. Ins. Physiol, (in press). NOGGE, G., Proteolytic enzymes of the larvae of Hypoderma bovis (De Greer) (Díptera, Hypodermatidae) (in German), Z. Parasitenk. 38 (1972) 285-94. NOGGE, G., Investigations on extra-intestinal digestion in the larvae of Hypoderma bovis (De Greer) (Díptera, Hypodermatidae) (in German), Z. Parasitenk. 3£ (1972) 295-302. SCHAUB, B., Respiratory behaviour and orientation in a temperature gradient as a function of temperature adaptation in parasitic Calliphoridae larvae (in German), Diploma thesis (1972). ZEISS, V., A contribution to the ontogenesis, histology and secretory activity of the mesenteric tract in different larval stages of Callltroga macellaria (Fabricius) (in German), Thesis fot State Examination (1972). 44 RESEARCH CONTRACTS AND AGREEMENTS Nos 523, 608, 614, 622, 623, 628, 639, 654, 655, 680, 716, 728, 861, 956 and 992 Summary of final report IAEA-R-523-F TITLE Co-ordinated program of research on the use of isotopes and radiation in wheat fertilization studies. COUNTRIES PARTICIPATING Arab Republic of Egypt, Brazil, Greece, Hungary, India, Iran, Italy, Lebanon, Mexico, Morocco, Pakistan, Peru, Romania, Turkey, Uruguay. RESEARCH INSTITUTIONS AND PRINCIPAL INVESTIGATORS Arab Republic of Egypt M.T. Eid Physiology and Crop Nutrition Division; Later M.R. Hamissa Plant Nutrition Research Section, Ministry of Agriculture, Orman, Giza. Brazil A.M.L. Neptune; later A. Cervellini Centro de Energia Nuclear na Agricultura, Piracicaba, S.P. Greece C. Apostolakis Greek Nuclear Energy Commission, Democritos Nuclear Research Center, Aghia Paraskevi, Athens. Hungary J. Dombovari Research Institute for Irrigation and Rice Cultivation, Szarvas. India S.S. Bains (deceased); later M. N. Sinha Indian Agricultural Research Institute, Division of Agronomy, New Delhi. 45 Iran M. Dianati Tehran University Nuclear Center, Tehran. Italy G. Picciurro Comitato Nazionale per l1 Energia Nucleare, Laboratorio Applicazioni in Agricultura, Rome. Lebanon A. Shammas Agricultural Research Institute, Tel Amara par Rayak. Mexico L. Lopez Martinez de Alva Instituto Nacional de Energia Nuclear, Mexico 18 D.F. Morocco J. Roderbourg Ministère de l'agriculture et de la réforme agraire, Direction de la recherche agronomique, Rabat. Pakistan A . Hamid Nuclear Institute for Agriculture and Biology, Lyallpur. Peru J. Lugo C. Estación Experimental Agricola de la Molina; Later M. Bravo Dirección General de Investigaciones Agropecuarias Lima. 46 Romania C. Hera Institute de Cercentari Pentru Cereale si Plante Tehnice, Fundlea, Bucharest. Turkey N. Uelgen Soil and Fertility Research Institute, Ankara. Uruguay A. Saravia Centro de Investigaciones Agricolas, "Alberto Boerger", La Estanzuela, Treinta y Tres. SCIENTIFIC BACKGROUND AND SCOPE OF THE PROGRAM Both in area under cultivation and total world production, wheat exceeds any other cereal crop. Its widespread cultivation in all the continents, its value in human diet — both as a source of carbohydrate and protein — and its baking qualities make it relatively more important than the other cereal grains. The development of new high-yielding fertilizer-responsive varieties and the breeding of new cultivars has enabled the extension of wheat-growing areas from temperate to sub-tropical and tropical areas. This, together with the growing interest in producing high-protein grain and the concern about inefficient fertilizer usage being a contributor to water pollution, pose many questions relative to the subject of efficient fertilizer usage. Efficient fertilizer practice aims at maximizing the utilization of applied fertilizer by the crop. This calls for quantitative information on how the actual amount of fertilizer taken up by the crop varies with the different practices involved in fertilizer application. Information on the time and frequency of application, method of placement, chemical source of the ferti- lizer and irrigation practices in relation to the soil and climatic conditions under which the crop is grown is necessary to provide a basis for sound ferti- lizer management practices. Such quantitative information can be directly obtained only by isotope labelling of the nutrient element in the fertilizer and measuring the amount of isotopically labelled nutrient taken up in the crop through actual field experiments. The primary objectives of this program were directed towards studying the effects of time of application and source of nitrogen on its utilization by wheat. The experiments also included studies on the placement of nitrogen and phosphate fertilizers and the effect of irrigation on nutrient uptake. 47 ORGANIZATION OF THE PROGRAM The program was implemented through research contracts awarded by the IAEA to the principal investigators at selected research institutes. Funds were provided under the research contract for the supply of isotopically labelled fertilizer materials and for the travel of contractors to research co-ordination meetings. In addition, the Agency's laboratory at Seibersdorf carried out 15N analyses on all the straw and grain samples from the experi- ments carried out by the contractors. The participants in the program met annually to plan the common experi- ment to be done each year and discuss the previous year1 s results. On the basis of the decisions reached at each such research co-ordination meeting, the project officer of the IAEA responsible for the program prepared detailed instructions for each year' s experiment. All the basic information for each experiment was recorded by the principal investigator in the special field record book sent to him by the Agency. The completed record books were returned to the project officer and the data was statistically analysed and included in the Technical Report of the program. SUMMARY OF THE RESULTS Increased grain yields due to the addition of nitrogen occurred in almost all of the experiments conducted over the four years of the program. In some instances these yield responses were quite dramatic and clearly illus- trate the need of fertilizer nitrogen for obtaining maximum economic pro- duction of wheat. The per cent protein in the grain was also generally increased by the addition of nitrogen, a point that is not always fully appreciated. Data from the four years of the program have generally shown that split applications of nitrogen are superior in supplying nitrogen to wheat than a single application at planting. This superiority is due largely to greater uptake efficiency from the portion of the nitrogen applied at the tillering stage of growth. The placement of starter amounts of nitrogen (20 kg/ha) directly with the seed had very similar effects on nitrogen uptake and yield components as did a side-band application of the same amount. These results indicate that for wheat it is of no advantage to side- band small amounts of nitrogen fertilizer, which is often a more expensive operation, rather than placing the fertilizer directly with the seed. However, caution must be exercised that excessive amounts of nitrogenous fertilizer are not placed directly with the seed in order to avoid seedling injury. The effectiveness of ammonium nitrate, urea and ammonium sulphate as fertilizer sources of nitrogen for wheat was remarkably similar. In a few individual experiments differences in relative effectiveness of the different carriers were recorded, but the reasons for these exceptions were not apparent. Per cent phosphorus derived from the fertilizer (% Pdff) data obtained in these experiments indicated that the ammonium ion, when intimately mixed with phosphate fertilizer, frequently has a beneficial effect on fertilizer phosphorus uptake by wheat. In general, however, this effect was not as large as that observed in previous programs for rice and maize. 48 RESEARCH CONTRACT No. 1027 Summary of final report IAEA-R-541-F TITLE Development of artificial feeding and mass-rearing of the tsetse fly Glossina morsitans and G. sub-morsitans (part of a co-ordinated program on the control of animal insect pests by the sterile-male technique). RESEARCH INSTITUTION National School of Public Health and Tropical Medicine, Lisbon, Portugal. PRINCIPAL SCIENTIFIC INVESTIGATOR J. Fraga de Azevedo. PERIOD OF CONTRACT 15 August 1967 - 30 September 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT To develop the sterile-male technique for tsetse fly control methods for mass rearing are essential. This contract dealt with developing rearing methods for tsetse flies. EXPERIMENTAL METHODS The experimental methods used inthis projectwere adequate. Essentially the investigators worked on mass production of tsetse fly, including feeding through artificial membranes. RESULTS OBTAINED The results on mass production of tsetse flies on animals were excellent. A large amount of data was obtained, which has been and will be used by other researchers in rearing this insect. In addition the contractors were able to supply a limited number of laboratory-reared tsetse flies to co-operators in Africa for comparative studies with native insects. The artificial membranes utilized were not entirely successful; however, no artificial membrane tested by any researcher has been completely success- ful. The results obtained in the present work as well as the results of other researchers indicate that the membrane is not the primary obstacle but the media (blood) under the membrane. CONCLUSIONS Tsetse flies can be maintained in the laboratory providing great care is used in preventing contamination from insecticides and/or bacteria. 49 Laboratory-reared tsetse flies have been shown to be well adapted for field releases. No statistical difference was found between groups of tsetse flies fed daily and fed on alternate days. PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACT AZEVEDO, J. Fraga de, O sentido evolutivo actual da doença do sono no Ultramar Portugués, O Médico 816 (1967) 1-7. AZEVEDO, J. Fraga de, PINHÄO, R.C., Tse-tse fly colony in Lisbon: Accidental Insecticide Contamination, Org. Mond. Santé, Trip/Inf. / 67.17 (1967). AZEVEDO, J. Fraga de, Geografía médica da doença do sono, Rev. Inst. Med. Trop. Sao Paulo 9 4 (1967) 239-94. AZEVEDO, J. Fraga de, PINHÄO, R. C., 'Prospects offered by the laboratory breeding of Glossina morsitans in Lisbon", Control of Livestock Insect Pests by the Sterile-male Technique (Proc. Panel Vienna, 1967), IAEA, Vienna (1968). AZEVEDO, J. Fraga de, PINHAO, R.C., SANTOS, A.M. T., FERREIRA, A. E., Studies carried out with the Glossina morsitans colony of Lisbon. I — Some aspects of the evolution of the Glossina morsitans colony of Lisbon, An. Esc. Nac. Saflde Pflbl. Med. Trop. 2 1-4 (1968) 19-42. AZEVEDO, J. Fraga de, PINHÄO, R.C. , Studies carried out with the Glossina morsitans colony of Lisbon. II - Aspects of the tsetse flies appreciated by "soft" X-rays, An. Esc. Nac. Sadde Pdbl. Med. Trop. 2 1-4 (1968) 43-50. AZEVEDO, J. Fraga de, PINHÄO, R. C., SANTOS, A. M. T. , Biological studies carried out with the Glossina morsitans colony of Lisbon. Ill - Hypothetical control of the tsetse fly in Principe Island by the sterile-male technique, An. Esc. Nac. Saflde Pflbl. Med. Trop. 2 1-4 (1968) 51-59. AZEVEDO, J. Fraga de, GOMES, F. A. C., PINHÄO, R. C. , Biological studies carried out with the Glossina morsitans colony of Lisbon. IV — Utilization of 3?P and 6"Co in the study of biology of Glossina morsitans, An. Esc. Nac. Saúde Públ. Med. Trop. 2 1-4 (1968) 61-67. AZEVEDO, J. Fraga de, PINHAO, R.C., SANTOS, A.M. T., Artificial breeding of tsetse fly. I. - Factors connected with the feeding membrane and blood meals type, An. Esc. Nac. Saflde Pflbl. Med. Trop. 2 1-4 (1968) 11-17. AZEVEDO, J. Fraga de, Imunopatologia da doença do sono, Imunopatologia Tropical, livrario Atheneu SA, Rio de Janeiro (1969) 153 - 68. AZEVEDO, J. Fraga de, PINHÄO, R.C., F REIT AS, R. , GOMES, F.A.C., SANTOS, A. M. T. , FERREIRA, A.E., As radiaçoes e os radioisótopos na investigado entomológica. Sua aplicaçao ao estudo da mosca tsé-tsé. Mem. Acad. Ciênc. Lisboa 13 (1969) 43-87. AZEVEDO, J. Fraga de, SANTOS, A. M. T. , PINHÄO, R. C. , GUERREIRO, J.P. , Problems and prospects offered by tsetse artificial breeding, An. Esc. Nac. Saflde Pflbl. de Med. Trop. 3 1-4 (1969) 125-35. AZEVEDO, J. Fraga de, PINHÄO, R.C., Alguns aspectos biológicos da colonia de mosca tsé-tse de Lisboa, Mem. Acad. CiSnc. Lisboa 13 (1969) 7-42. DAMO, D. A. , AZEVEDO, J. Fraga de, SMITH, H.C., FERREIRA, A. E. ."Behavior of colonized and native male Glossina morsitans orientalis Vanderplank in laboratory",Criaçào da Mosca Tsé-tsé no Laboratorio e sua Aplicaçao Prática (Proc. Symp. Lisbon, 1969), (1970) 91-96. PINHÄO, R.C., AZEVEDO, J. Fraga de, FERREIRA, A.E. , "The breeding of Glossina submorsitansin the laboratory", Criaçâo da Mosca Tsé-tsé no Laboratório e sua Aplicaçao Prática (Proc. Symp. Lisbon, 1969), (1970) 177-88. AZEVEDO, J. Fraga de, SANTOS, A.M. T. , PINHÄO, R.C. , "Artificial breeding of tsetse fly. II. - New data on the feeding membrane and blood meals type of Glossina morsitans", Criaçâo da Mosca Tsetse no Laboratorio e sua Aplicaçao Prática (Proc. Symp. Lisbon, 1969), (1970) 199-209. 50 AZEVEDO, J. Fragade, SANTOS, A.M. T., "Evolution des muscles thoraciques dans la Glossina morsitans élevée au laboratoire", Criaçâo da Mosca Tsé-tsé no Laboratorio e sua Aplicaçâo Prática (Proc. Symp. Lisbon, 1969), (1970) 287-416. AZEVEDO, J. Fraga de, BARREIRA, F., GUERRE1RO, Y.C.P. , PRAZERES, A. R. , T AVARES, R. . GOMES, F. A. C. , "Utilization of khymidine MC in the study of biology of Glossina morsitans", Criaçâo da Mosca Tsé-tsé no Laboratorio e sua Aplicaçâo Prática (Proc. Symp. Lisbon, 1969), (1970) 417-420. LAVADINHO, A. P., AZEVEDO, J. Fraga de, "First results concerning the susceptibility of the Lisbon colony of Glossina morsitans to DDT", Criaçâo da Mosca Tsé-tsé no Laboratorio e sua Aplicaçâo Prática (Proc. Symp. Lisbon, 1969), (1970) 421-27. AZEVEDO, J. Fraga de, SANTOS, A.M.T., SOUSA, A., "New attempts at sex differentiation of tsetse fly pupae by X-rays", Criaçâo da Mosca Tsé-tsé no Laboratörio e sua Aplicaçâo Prática (Proc. Symp. Lisbon, 1969), (1970) 435-40. AZEVEDO, J. Fraga de, "An attempt for distribution of research work on tsetse fly breeding", Criaçâo da Mosca Tsé-tsé no Laboratorio e sua Aplicaçâo Prática (Proc. Symp. Lisbon, 1969), (1970) 487-96. AZEVEDO, J. Fraga de, "Prospect about international research work on tsetse flies", Criaçâo da Mosca Tsé-tsé no Laboratorio e sua Aplicaçâo Prática (Proc. Symp. Lisbon, 1969), (1970) 497-502. FREIT AS, J. B., AZEVEDO, J. Fraga de, GOMES, F. C., FERREIRA, A. E., Retençâo do alimento pelo Glossina morsitans West, determinada pelo ssFe, Garcia de Orta 17 2 (1969) 147-56. FREITAS, J. B., AZEVEDO, J. Fraga de, PINHÄO, R. C., Frequência do alimentaçâo em Glossina morsitans West, Garcia de Orta 17 2 (1969) 157-66. AZEVEDO, J. Fraga de. Ed., Criaçâo da Mosca Tsé-tsé no Laboratorio e sua Aplicaçâo Prática, (Proc. Symp. Lisbon, 1969), (1970). AZEVEDO, J. Fraga de, GUERREIRO, J. P., An attempt at the laboratory breeding of Glossina pallidipes Austen 1903, An. Esc. Nac. Saúde Públ. Med. Trop. 5 1-2 (1971) 3-8. AZEVEDO, J. Fraga de, AFONSO, M.M., Evolution of pupal weight of two Lisbon colonies of Glossina morsitans. An. Esc. Nac. Saude Públ. Med. Trop. 5 1-2 (1971) 9-15. AZEVEDO, J. Fraga de, Relationship between the species vectors of tsetse Hies and the pathogenicity and anti- genic characteristics of the Brucei-group trypanosomes, An. Esc. Nac. Saúde Públ. Med. Trop. 5 1-2 (1971) 91-98. AZEVEDO, J. Fraga de, Problems offered by the artificial breeding of tsetse flies, An. Esc. Nac. Saúde Públ. Med. Trop. 5 1-2 (1971) 131-38. AZEVEDO, J. Fraga de, "Sublethal toxicity of DDT to tsetse flies", Toxicology, Biodegradation and Efficacy of Livestock Pesticides, Research Station, Lethbridge, Alberta (1972) 398-409. AZEVEDO, J. Fraga de, SANTOS, A.M.T. , GUERREIRO, J. P., FERREIRA, A.E., Estudo evolutivo da colonia de Glossina austeni mantida no laboratorio (in press). SANTOS, A.M.T., AZEVEDO, J. Fraga de, Some caging experiments on the Glossina austeni colony of Lisbon, J. Invest. Utramar (in press). 51 RESEARCH CONTRACT No. 1070 Summary of final report IAEA-R-612-F TITLE Haemal and environmental factors regulating tsetse fly feeding activity (part of a co-ordinated program on the control of animal insect pests by the sterile-male technique) RESEARCH INSTITUTION University of Nairobi, Department of Entomology, Nairobi, Kenya. PRINCIPAL SCIENTIFIC INVESTIGATOR T.R. Odhiambo. PERIOD OF CONTRACT 1 April 1968 - 30 September 1973. EXPERIMENTAL METHODS AND RESULTS OBTAINED A number of basic experiments were conducted to better understand the feeding activity of adult tsetse fly, including G. pallidipes, G. morsitans, (3. austeni and G. brevipalpis. A membrane of bat wings was developed for salivation studies. Various host animals were utilized during these experi- ments, including rabbits, goats, cattle and guinea-pigs. In studies with guinea-pigs of various developmental stages it was found that mature male and virgin female guinea-pigs were the best hosts for G. pallidipes. Infant guinea-pigs were very poor hosts. A morphological study of the salivary glands of adult tsetse flies showed there were five morphologically distinct areas. These were determined by light and electron microscopy as well as histological techniques. The digestive process in adult tsetse flies was investigated. Various unidenti- fied protein products were determined at intervals of time after feeding. The results of studies of salivation demonstrated that this process did not occur until after the adult fly had pierced the membrane. The saliva of tsetse flies contains an anticoagulant, which prevents clotting of the blood during feeding. Removal of the saliva glands did not prevent the flies from feeding, but did result in bloodclots forming in the proboscis channel. The quantity of saliva produced by adult tsetse flies was correlated with the amount of feeding, that is the more saliva produced on a particular day, the higher the probability that the adult fly would take a blood meal. Tsetse flies that had not fed for 2 or 3 days salivated more profusely than recently fed flies. Attempts to label saliva with tritium (by injection) or with labelled thymidine were unsuccessful. 52 RESEARCH CONTRACT No. 729 Summary of final report 1AEA-R-729-F TITLE Use of isotopes in studies on the nutrition of groundnuts (part of a co-ordination program of research on the use of isotopes and radiation in studies of physico-chemical relationships of soils and plants). RESEARCH INSTITUTION Soil Research Institute, Ghana Academy of Science, Kumasi, Ghana. PRINCIPAL SCIENTIFIC INVESTIGATOR C.S. Ofori. PERIOD OF CONTRACT 1 February 1969 - 30 November 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT Groundnuts are an oil crop of economic importance grown throughout West Africa, especially in the Savannah Belt extending from Senegal to Northern Nigeria and including Ghana. The importance of the crop to the economy of countries in the region has led to considerable interest in the crop's response to fertilizers. Sulphur and phosphorus in particular have been recognized as the two nutrients limiting groundnut production. While broad field-scale fertility experiments have been carried out in some West African countries, little has been known about fertilizer manage- ment practices such as placement, optimum time of application or optimum rate of application of the three nutrients nitrogen, phosphorus and sulphur known to be deficient in the soils of the Savannah Belt area. The use of fertilizers labelled with radioactive or stable isotopes offers the best method of obtaining direct quantitative information on the efficiency of various methods and times of fertilizer application. The objectives of the project were to study: (i) The efficiency of different methods of applying phosphate fertilizer (ii) The effect of sulphur and nitrogen on phosphorus utilization and yields of different varieties of groundnuts', (iii) The influence of rate and time of nitrogen application on yields and efficiency of nitrogen utilization. EXPERIMENTAL METHODS Field experiments were carried out using fertilizer materials labelled with 32P, 35S and 1SN on groundnuts planted on sandy loam soil types. The experiments consisted of randomized block designs replicated three or four times. Treatment effects were evaluated through measurements of yields and uptake of labelled fertilizer in the plants. 53 RESULTS OBTAINED Phosphorus (superphosphate) gave significant yield responses at 40 kg P205/ha. The differences in fertilizer uptake between band and broadcast applications were not statistically significant, but during the early stages of growth band application tends to be superior. Highest kernel yields were obtained when half the phosphate was broadcast at planting and the rest was banded three weeks after germination. Growth habit of the variety, whether erect or semi-spreader, had no significant effect on phosphate utilization. Sulphur (sodium sulphate) at 15 kg S/ha increased forage yields, but decreased yields at 30 kg/ha. However, sulphur depressed kernel yields at both rates of application. Sulphur increased the absorption of fertilizer phosphorous in underground portions of the plant, but not in forage. Nitrogen applied as ammonium sulphate or urea showed no yield responses beyond 15 kg N/ha, except on a site which had been under grass fallow. Fertilizer phosphorus absorption increased when nitrogen was applied with the phosphate. Kernel yield and utilization of fertilizer nitrogen was highest when nitrogen was applied at planting. Late application of nitrogen depressed kernel yields and reduced its efficiency of utilization. However, time of nitrogen application had no effect on crude protein content of kernels. Ammonium sulphate was found to be as efficient a source of nitrogen as urea. CONCLUSIONS The results provide useful information on the problems studied — infor- mation that is of practical value for groundnut cultivation. The studies on phosphate placement have shown that the current time-consuming practice of placing fertilizer around individual plants can be replaced by the simpler method of banding all in furrows at planting or broadcasting half a planting and banding the rest 3 weeks after germination. Phosphate applications give significant yield responses. Although sulphur has been reported to give yield responses in many experiments in West Africa, no effects were found in the present studies. It is concluded that on these soil types sulphur is not required. The sulphur requirements of the groundnut varieties used in this study are comparatively low and adequately met from the soil source. Nitrogen applications showed little yield responses except at one site where the land had been.under grass fallow for some time. When nitrogen is required, it should be applied at planting, not at flowering or later, in order to ensure maximum efficiency of utilization and avoid suppression of the N-fixing process. Generally, even though no inoculation is practised, there seems to be adequate native rhizobium for symbiotic N-fixation. PAPER PUBLISHED ON WORK DONE UNDER THE CONTRACT OFORI, C. S., The influence of nitrogen and sulphur on the absorption of fertilizer phosphorus and the yield of groundnut grown on soil of granitic origin, Oléagineux 28 (1973) 21-23. 54 RESEARCH CONTRACT No. 1070 Summary of final report IAEA-R-758-F TITLE Mass rearing methods for important lepidopterous pests of South East Asia (part of a co-ordinated program of rice insect control and eradication). RESEARCH INSTITUTION College of Education,Bangsaen, Thailand. PRINCIPAL SCIENTIFIC INVESTIGATOR T. Hormchong. PERIOD OF CONTRACT 1 June 1969 - 30 June 1973. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT The staple human diet of Asia is rice. This region produces two thirds of the world' s output in rice with an annual loss due to insect pests of some 8. 5 x 109 dollars. The greatest toll is taken by rice stem borers which include a number of species; some of the most important being; Chilo suppressalis, Chilotraea polychrysa, Sesamia inferons, Tryporyza incertulas and T. innotata. One of the major conditions to be met before any of these pests can be controlled by the sterile insect technique is a method for their mass pro- duction. To be practical, such a production should be carried out on an . artificial medium. The main objective of the project was to develop an inex- pensive artificial diet on which rice stem borers could complete their larval development. EXPERIMENTAL METHODS Eight different diets were screened, the standard being a modification of Vanderzant's wheat germ/casein diet. With these media a number of protein sources were tested on all five species of borers. These proteins were: non- fat powdered milk, dry milk (lactogen), pinto beans, brewer's yeast and yeast extract. A further six media, including the wheat germ diet, were tested on C. suppressalis. Brewer's yeast, cholesterol and a dry preparation of Wolffia arhyza (Lemnaceae) were tested in single-factor comparisons. Duck wheat, mung bean and a local soy bean-protein preparation (Kaset) also were tested as wheat germ substitutes. The effects of various levels of propionic acid in wheat germ diet on the yield and pupal weights of C. suppressalis were com- pared. Likewise, the effects of two local proprietary vitamin preparations 55 replacing the standard vitamin mixture were tested with this diet. The development of C. suppressalis individually and collectively reared on wheat germ diet was studied during a number of consecutive generations. RESULTS OBTAINED Wheat germ/casein medium could be used for rearing C. suppressalis, C. polychrysa and S. infe rens but not for Tryporyza. The addition of brewer's yeast and/or cholesterol to the wheat germ/casein diet had no significant effect on the pupal yield of C. suppressalis. Replacing half or all the wheat germ by a preparation of Wo If fia highly significantly increased the pupal yield (from 41.0 to 60.5 and 72.0%, respectively). There were no significant differences in pupal yield between the Wolffia preparation and the local soy bean protein (Kaset). C. suppressalis did not pupate on the duck wheat or mung bean substitutes. With propionic acid in the wheat germ diet pupal yield dropped from 84% at the 1.0 ml/1000 g diet level to 0% at the 3.0 ml/1000 g level. Likewise, pupal weight decreased with the amount of mould inhibitor. In the untreated control the pupal return was 50% but the pupal weight was higher. The development of C. suppressalis when the local proprietary vitamin preparation Panvitan replaced the imported standard vitamin mixture in the wheat germ diet was equally good. CI. suppressalis was reared on the wheat germ diet for 18 sequential generations, collectively and individually, without deterioration. The per cent pupation in the individual rearings was consistently higher (range .75.0 - 91.0%) than in the collective rearings (range 21.5 — 66.5%). CONCLUSIONS Three rice-stem borer species, C. suppressalis, C. polychrysa and S. inferens, can be reared on a wheat germ/casein diet. On this diet many sequential generations of C. suppressalis can be produced without deterio- ration. Production costs can be reduced by replacing wheat germ by either a preparation of Wolffia arhyza (Lemnaceae) or soy bean protein (Kaset). Likewise, a local proprietary vitamin preparation (Panvitan) is as good as the imported vitamin mixture component of the wheat germ diet. PAPER PUBLISHED ON WORK DONE UNDER THE CONTRACT HORMCHONG, T., SRITHUNYA, S., SITONG, P., "Mass rearing of rice stem borers", Proc. Symp. on Rice Insects, Tropical Agrie. Res. 5 (1971). 56 RESEARCH AGREEMENT No. 969 Summary of final report 1AEA-R-969-F TITLE Fate and significance of labelled pesticide residues in rice (part of a co-ordinated program of research on the fate and significance of foreign substances in food). RESEARCH INSTITUTION National Institute of Agricultural Sciences, Department of Plant Pathology and Entomology, Tokyo, Japan. PRINCIPAL SCIENTIFIC INVESTIGATOR C. Tomizawa. PERIOD OF AGREEMENT 15 December 1970 - 28 February 1973. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT The vital importance of rice in Japan and its protection against insect and fungus attack have dictated studies of the nature and significance of resi- dues of new and safer substitutes for the organo- mercurial fungicides and earlier insecticides. EXPERIMENTAL METHODS Pesticides were labelled with 32P and/or 35S and applied to rice plants, soil and experimental animals. The metabolic fate of the applied compounds was quantitatively and qualitatively studied by a combination of thin-layer, gas-liquid chromatographic and radioassay techniques. RESULTS OBTAINED The metabolic degradation of two new organophosphorus fungicides , Kitazin-P® and Hinosan®, both labelled with 32P and 35S in soil, in animals and rice plants were compared. Extensive degradation of both compounds was indicated by studies of the residues in rice grains. Two new organophosphorus insecticides, Padan® and Hokupanon®, used for controlling the rice stem borer, were similarly studied. Both compounds were extensively degraded following application to the rice plant.The compound di-isopropyl hydrogen phosphorothioate was detected as a relatively persistent metabolite of Kitazin-P® in rice grains. The sulphoxide of Hokupanon®was a relatively persistent metabolite in the rice plants. 57 CONCLUSIONS The main pathway of Kitazin-P in the rice plant is hydrolysis to provide di-isopropyl hydrogen phosphorothioate. Metabolism of Hinosan depended on the cleavage of the P-S bond to produce benzenethiol and its oxidative products. In rice plants Padan was rapidly converted to N, N-dimethyl-1 2-dithiolane-4-amine. Hokupanon was similarly and rapidly converted to N' - (4- chloro- o- tolyl)- N- methyl- N- methylsulphinylmethyl formadine but subsequent degradation was relatively slow. New effective fungicides and insecticides are available for protecting rice and these studies suggest that metabolic pathways exist that will obviate the persistence of toxic residues. Toxicological studies of the persistent metabolites in harvested rice grains will be required and should be based on the metabolic studies summarized above. 58 RESEARCH CONTRACT No. 1070 Summary of final report IAEA-R-985-F TITLE Irradiation of Theileria parva, the causative organism of East Coast Fever of cattle, in its tick vector (part of a co-ordinated program on the use of isotopes and radiation in studies of the etiology, effects and control of parasitic diseases in domestic animals). RESEARCH INSTITUTION Protozoology Division, East African Veterinary Research Organization, Muguga, Kikuyu, Kenya. PRINCIPAL SCIENTIFIC INVESTIGATOR R.E. Purnell. PERIOD OF CONTRACT 1 January 1971 - 31 December 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT East Coast Fever of cattle was designated by the FA O East African Live- stock Survey (1967) as the major parasitic disease of livestock retarding the growth of the livestock industry in East Africa. The FAO tick-borne diseases project was inaugurated on the basis of this report, and its primary objective is to produce a vaccine against ECF. The anticipated project was closely co-ordinated with the FAO project. Preliminary results on the irradiation of infective particles of Theileria parva (the causative organism of ECF) had been encouraging, and the possibility of producing a vaccine by irradiating developing T. parva parasites in their tick vector was therefore investigated. It has been indicated elsewhere that irradiation of Theileria annulata in the tick Hyaloma anatolicum anatolicum results in the production of a mild disease when the irradiated ticks are subsequently applied to cattle. Such cattle were resistant to challenge with non-irradiated ticks. The staff of the FAO tick-borne diseases project, in collaboration with Dr. J.D. Dargie, initiated a series of experiments using irradiated infective particles of Theileria parva. Their results indicated that inoculation of irradiated parasites will produce immunity in cattle to an otherwise fatal challenge. However, the tolerance limits of the number of parasites irradi- ated and the irradiation dose were not broad, and the likelihood of producing a safe vaccine by this method is not great. EXPERIMENTAL METHODS In a series of experiments, ticks that had engorged an infected Bos taurus type steer were irradiated with a 60Co source at doses varying between 1 to 60 Wad. Some of the irradiated ticks were fed on rabbits'/ ears for 4 to 8 days 59 and their salivary glands examined for infective parasites and acini, others were used to infect 1 clean' cattle either directly or by making a sus- pension of infective particles for inoculation of the cattle. The serological and pathological response of the cattle was measured. RESULTS OBTAINED Engorged nymphs irradiated at 1 krad moulted normally, those irradiated at 2 krad took 3 days longer, and those at 4 krad did not moult. Moulting nymphs moulted normally up to doses of 16 krad but those irradiated at 32 krad took 4 days longer and then died or failed to feed normally from rabbits. Irradiating engorged nymphs at 2 krad reduced the number of parasites present in the salivary gland of the resulting adult tick and either reduced the size of the salivary glands or arrested its development completely. The parasites from the salivary glands of the adults that developed from irradi- ated moulting engorged nymphs (up to 16 krad) were morphologically normal. When adult ticks were irradiated, the number of parasitized acini con- taining infective particles decreased with increased irradiation dose but only at dose rates of 60 krad were no infective particles observed in the acini. Cattle inoculated with suspensions from the irradiated ticks responded in the manner predicted from the observations on the ticks' salivary glands. More parasites were killed as the irradiation dose increased but there was no successful attenuation of the infective parasites. At the lower levels of irradi- ation (<15 krad) many animals died of East Coast Fever resulting from the inoculation and those treated with parasites irradiated at doses of more than 20 krad showed no response to the inoculation but died on challenge. CONCLUSIONS As the irradiation dose increases, the number of parasites killed in the salivary glands of unfed adult ticks increases and there is some evidence that the development of the parasite in the ticks' salivary glands is delayed. Inoculum produced from ticks irradiated at doses of less than 20 krad caused East Coast Fever in cattle but the few survivors were resistant to a further challenge. Inoculum from ticks irradiated at doses of greater than 20 krad did not produce East Coast Fever but the cattle, with one exception, were susceptible to a lethal challenge. A situation could not be produced where a uniformly attenuated sus- pension of parasites was obtained. An irradiation dose of 20 krad gave some evidence of an attenuating effect but the margin of safety about this dose was too narrow and the results too variable for such a treatment to be used as practical control measure. The possibility of producing an irradiated, tick- derived vaccine against East Coast Fever is remote. PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACT PURNELL, R. E., DARGIE, J. D., GILLIVER, B., IRV1N, A.D., LEDGER, M.A., Parasitology 64 (1972) 429-40. PURNELL, R. E., LEDGER, M.A., OBATRE, J. B., Parasitology 65 (1972) 23-26. PURNELL, R. E. , DARGIE, J. D., IRVIN, A. D., LEDGER, M.A., Isotopes and Radiation in Parasitology m (Proc. Research Co-ordination Meeting, Kenya, 1971), IAEA, Vienna (1973) 139-44. 60 PURNELL, R.E. , BROWN, C.G.D., BURRIDGE, M.J. , CUNNINGHAM, M.P. , EMU, H., IRVIN, A.D., LEDGER, M.A. , NJUGUNA, L.M., PAYNE, R. C., RADLEY, D.E., East Coast Fever: The effect of 60Co- irradiation of ticks infected with Theileria parva on the subsequent infectivity of the parasites for cattle, submitted for publication. CUNNINGHAM, M.P., BROWN, C. G. D., BURRIDGE, M.J., MUSOKE, A.J., PURNELL, R. E. , DARGIE, J. D. , East Coast Fever of cattle:60 Co-irradiation of infective particles of Theileria parva, submitted for publication. CUNNINGHAM, M.P., BROWN, C. G. D., PURNELL, R.E., MUSOKE, A. J., BURRIDGE, M. J., DARGIE, J. D. , Isotopes and Radiation in Parasitology III (Proc. Research Co-ordination Meeting Kenya, 1971), IAEA, Vienna (1973) 145-54. BROCKLESBY, D.W., PURNELL, R. E., SELLWOOD, S.A., Br. Vet. J. 128 (1972) iii-iv. PURNELL, R. E., BROCKLESBY, D.W., SELLWOOD, S.A., Isotopes and Radiation in Parasitology in (Proc. Research Co-ordination Meeting Kenya, 1971),IAEA, Vienna (1973) 169-71. PURNELL, R.E., SANSOM, B.F., SELLWOOD, S.A., Res. Vet. Sei. 13 (1972) 102-3. PURNELL, R. E., SANSOM, B. F., SELLWOOD, S. A. , Isotopes and Radiation in Parasitology III (Proc. Research Co-ordination Meeting Kenya, 1971), IAEA, Vienna (1973) 161-63. IRVIN, A.D., BROWN, C. G. D., BOARER, C. D. H., CRAWFORD, J. G., KANHAI, G.K. , Res. Vet. Sei. (in press). IRVIN, A.D., BROWN, C. G. D., CUNNINGHAM, M.P., CRAWFORD, J. G., LEDGER, M.A., Nature New Biol. 236 (1972) 106-7. IRVIN, A.D., BROWN, C. G. D., CUNNINGHAM, M.P., CRAWFORD, J. G., LEDGER, M.A., Isotopes and Radiation in Parasitology III (Proc. Research Co-ordination Meeting Kenya, 1971), IAEA, Vienna (1973) 155-59. 61 RESEARCH CONTRACT No. 1070 Summary of final report IAEA-R-1070-F TITLE Control of the fall webworm (Hyphantria cunea Drury) by gamma steri- lization of males (part of a co-ordinated program on the use of the sterile- male technique of control of lepidopterous insects attacking fruit and forest trees). RESEARCH INSTITUTION Research Institute for Plant Protection, Bucharest, Romania. PRINCIPAL SCIENTIFIC INVESTIGATOR C. Beratlief. PERIOD OF CONTRACT 1 December 1971 - 30 November 1973. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT The fall webworm (Hyphantria cunea Drury) was introduced into Europe from North America over 30 years ago, but has spread rapidly in Europe, defoliating harvests, fruit and ornamental trees and shrubs. The present study was to conduct research leading to the control of the fall webworm by the sterile-male technique. EXPERIMENTAL METHODS Two new diets were tested; one contained mulberry leaf powder as a phagostimulating agent. In the other diet agar was replaced by wheat starch and included wheat germ asaprotein source. Larvae were fed on leaves of nine tree species and insect growth was recorded. Males irradiated with 7.5, 15.0 or 22. 5 krad of gamma irradiation were mated with untreated females. The Fi males were treated with 7.0 krad and also mated with untreated females. Sexual competitiveness of irradiated males was measured using Fried1 s parameters. Overwintering pupae (3805) and pupae from the summer generation (3611) were collected from four different natural sites near Bucharest and examined for parasites and disease. The seasonal occurrence and intensity of H. cunea flights were determined by light traps. Testes of moths irradiated with 45 krad of gamma radiation as pupae were removed 2-3 days after emergence. Ultrastructural changes were observed. 62 RESULTS OBTAINED Hyphantria cunea Drury were reared on both artificial diets; however, further diet improvements are needed. A phagostimulating ingredient such as mulberry leaf powder may be important for larval acceptance of the diet. The larval acceptance and the percentage of the larvae reaching maturity decreased as the number of larvae per 720-ml glass jar increased from 25 to 100. The maximum percentage of larvae reaching maturity was 45%. On the best diet females weighed 81. 3 mg and laid 325 eggs of which 97.6% hatched. H. cunea were fed and matured on leaves of nine tree species. The weights of the female pupae decreased with the host in the following order: mulberry, apple, plum, walnut, sweet cherry, willow, sour cherry, apricot and pear. When males treated as pupae with 15 krad of gamma irradiation were mated with untreated females, 20. 1% of the resulting eggs hatched, but none of the larvae reached maturity. At 7. 5 krad 34. 2% of the eggs hatched and 43.6% of the larvae reached maturity. The F^ males were treated with 7.0 krad of radiation and mated with untreated females. From these matings 18. 6% of the eggs hatched and 10. 3% of larvae reached maturity. Sexual competitiveness of males irradiated as pupae with 45 krad of gamma radiation was reduced 35%. Pupal parasitization of field populations of H. cunea was not important; however, 17% of the pupae of the overwintering generation were infected with the fungus, Beauveria spp. Light-trap studies indicate two generations of H. cunea per year. The first flight in Bucharest began April 28, peaked on May 8 and emergence ended May 30. The second flight began on July 13, peaked between July 2 3 and 2 7 and emergence ended on'August 26. Most of the moths caught in light traps were males. Traps baited with virgin females did not catch many moths. Male adults treated with 45 krad suffered ultrastructural changes in the testes. These changes consist in modifications of the structure of spermatids and spermatozoids. A disorganization of the structure of the axial filament and mitochondrial bodies was frequently noted, consisting in a volume reduction, an increase in the number of atypical seminal elements, a significant vacuo- lization of the perinuclear cytoplasm, a reduction of isogenic elements within the cysts, and a change in their space arrangement. The nutritive cells forming the cyst walls were most affected by radiation; the cytoplasm of the nutritive cells was heavily vacuolized, and the lipid content greatly reduced. CONCLUSIONS H. cunea diets may require a phagostimulating ingredient such as mulberry leaf powder. Sterilization doses as low as 15 krad could be used in a release program, as for Fx sterility 7. 5 krad. Males from pupae treated at 45 krad are 65% competitive; however, a lower dose would be used in a release program. Treatment of male pupae with 45 krad resulted in ultrastructural changes in the gonads. Parasites are not important in population control of H. cunea. There are two flights of H. cunea, each lasting 4-5 weeks. H. cunea feeds on a number of hosts; however, of those tested mulberry produced the largest insect. 63 PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACT BERATLIEF, C., BOGULEANU, Gh., Effects of gamma radiation on Hyphantria cunea Drury pupae, Anal. Inst. Cere. Prot. Pl. 9 (1973) 390-99. BERATLIEF, C., BOGULEANU, Gh., Mass rearing of the Hyphantria cunea Drury (in press). 64 RESEARCH CONTRACT No. 1070 Summary of final report IAEA-R-1204-F TITLE Field performance of released normal and radiation sterilized olive fruit flies in a grove in Northern Greece (part of a co-ordinated program on the control or eradication of fruit flies by the sterile-male technique). RESEARCH INSTITUTION University of Thessaloniki, Laboratory of Applied Zoology and Parasi- tology, Thessaloniki, Greece. PRINCIPAL SCIENTIFIC INVESTIGATOR M.E. Tzanakakis. PERIOD OF CONTRACT 15 July 1972 - 14 July 1973. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT The work described was part of another larger project involving the release of radiation-sterilized olive flies to control the natural population in some small olive groves of Northern Greece (Halkidiki, Thessaloniki). Since no data were available on the levels of the adult population throughout the year in the groves selected, the main objective of this work was to determine seasonal fluctuations in the native adult population, its sex ratio as well as in the sexual maturity of the females and the per cent inseminated. This ecological information is essential for timing releases of radiation-sterilized individuals for the control of the native population by the sterile-male tech- nique in the area considered. EXPERIMENTAL METHODS A network of McPhail fly traps baited with 3% protein hydrolysate (Rhodia protein — a proprietary compound) in water was established in three olive groves about 3 km apart. These traps were serviced twice a week. Foreach grove native adults trapped were recorded as to the number and sex and the females were dissected to detect the presence of sperm and mature eggs. RESULTS OBTAINED Adult olive flies are present throughout the year in or at least near the olive groves examined. The general trend of the adult population is to increase in April, subside in early summer, reach a seasonal peak in Sep- tember — October and then subside again. 65 During the year, females represent roughly 30-60% of the trapped population. The proportion of females with mature eggs as well as those containing sperm increases from March to May, a period when temperatures are favour- able for egg maturation and mating, and suddenly drops in November with the onset of the cold. CONCLUSIONS In the area under consideration a low native population during winter and until early summer with increasing sexual maturity and mating from March to May are factors to consider in the proper timing of sterile olive fly releases. 66 FOOD TECHNOLOGY RESEARCH CONTRACT No. 839 Summary of final report 1AEA-R-839-F TITLE Irradiation preservation of Korean fish and shellfishery products. RESEARCH INSTITUTION Korea Institute of Science and Technology, Seoul, Korea. PRINCIPAL SCIENTIFIC INVESTIGATOR Jong Rak Chung. PERIOD OF CONTRACT 1 January 1970 - 31 December 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT Fish and shellfish are among those foods upon which the elevation of the nutritional status of the population heavily depends in many parts of the globe. The perishable nature of these commodities, however, gives rise to numerous transportation and preservation problems, which are not resolved by conventional preservation methods. Use of low-dose irradiation has been demonstrated to be effective in inactivating spoilage bacteria in fish and related products, thus extending their storage life. With the objective of achieving radurization of these food commodities, a 3-year study was undertaken at the Korea Institute of Science and Techno- logy to determine the species of Korean fish and shellfish that would be economically and technically feasible to be processed by irradiation for shelf-life extension under low-temperature storage. EXPERIMENTAL METHODS Five species offish, croaker (Nibera imbricate), yellow corvenia (Pseudoscianea manchuria), roundnose flounder (Xysteria grigorijewi), carp (Cyprinus carpió) and rainbow (Salmo gairdneric), and 3 species of shell- fish, Pacific oyster (Crassostrea gigas), hard clam (Meretrix lusoria) and mussel (Mytilus edulis), were irradiated at doses below 0. 5 Mrad, with the exception of carp, which received doses up to 1.5 Mrad. Postirradiation storage was carried out at 0°C and 5°C for a period of 35 days. Sensory evaluations were made at periodical intervals during storage employing the 9-point hedonic scale. In addition, total bacterial counts, total volatile bases (TVB) and trimethylamine (TMA) were estimated. Tyrosine content assessment and drip loss studies were undertaken for carp and trout. 67 The suitability of a number of locally available flexible film materials including polyethylene, polypropylene and aluminium with polyethylene lamina- tion were tested as packaging materials for the products before irradiation, RESULTS OBTAINED Among the film materials tested, only polyethylene laminated aluminium (Al+PE, 0. 03 + 0. 03 mil) was found suitable as a packaging material for all species investigated. It was observed that a radiation dose of 0. 2 Mrad was optimum for Pacific oyster and mussel and that a dose of 1. 0 Mrad was optimum for hard clam. By treating these species at the respective doses, it was possible to effect a four to five-fold increase in storage-life extension at 0°C, and six to seven-fold at 5°C for Pacific oyster. A two-fold extension of storage life was obtained for hard clams at 0°C and four-fold at 5°C. At 0°C dose levels of 0. 1 Mrad were found to be optimum for croaker and yellow corvenia, while a dose of 0. 5 Mrad was optimum when the two species were stored at a temperature of 5°C. In the case of roundnose flounder a dose of 0. 1 Mrad was considered optimum at both 0°C and 5°C. Doses of 0. 25 and 0. 05 Mrad were noted to be optimum for carp and trout respectively at both 0°C and 5°C storage. It was also observed that radiation treatment .of all species investigated resulted in significant reductions of their initial microflora. This was mani- fested by the suppression of TVB and TMA accumulations in the irradiated products during storage. Moreover, proteolysis was found to be suppressed. The drip loss in carp meat during storage was found to be quite exten- sive, increasing in amount with storage, and that irradiation augmented this trait. Dipping carp meat in 10% polyphosphate solution for 30 seconds prior to irradiation was found to nullify this adverse effect. CONCLUSIONS On the basis of these experiments, it appeared that carp, Pacific oyster and mussel would be the promising Korean fish and shellfish species for preservation by low-dose irradiation. The high radiation sensitivity of roundnose flounder and rainbow trout would render them unsuitable for radia- tion treatment. Radiation-inducedtissue softening in hard clams seemedto deter applicability of irradiation to this species of shellfish. A combined treat- ment of dipping in 10% phosphate solution followed by radiation treatment appeared to accord maximum preservation for carp meat. 68 RESEARCH CONTRACT No. 1070 Summary of final report IAEA-R-929-F TITLE Electrical (AC) resistance of irradiated fish for quality control and detection of irradiation treatment. RESEARCH INSTITUTION Institut für Strahlentechnologie der Bundesforschungsanstalt für Lebens- mittelfrischhaltung, Karlsruhe, Federal Republic of Germany. PRINCIPAL SCIENTIFIC INVESTIGATOR D. Ehlermann. PERIOD OF CONTRACT 1 October 1970 - 30 September 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT The 'Fish-tester' is an electronic device for the measurement of the freshness and quality of fish. Its operational principle is based on the simultaneous measurement of tissue impedance at two a. c. frequencies. In fresh tissues the capacitive contribution to the sample impedance is high. With the inception of spoilage, the contribution becomes lowered, reaching an asymptotic value when deterioration is perceptible by sensory methods. The quantity 'Q-value1 calculated from the impedances obtained could also be used as an index for the irradiation treatment of fish. Investigations relating to the identification of the radiation treatment in various fish species were undertaken. EXPERIMENTAL METHODS As the original 'Fish-tester' only operates at fixed frequencies of 1 and 16 kHz, an a. c. bridge assembly was devised for the measurement of tissue impedance in the frequency range of 110 Hz to 600 kHz. Trout was taken as a representative species of freshwater fish. Fresh samples of the fish were irradiated by 10-MeV electrons at dose levels rang- ing from 50-500 krad. Measurement of seafish of the redfish species was carried out on board the ship R. V. "Walther Herwig", which is equipped with an on-board X-ray irradiator. Treatment doses applied ranged between 50 and 200 krad. The course of the Q-values for several pairs of frequencies was examined to find combinations suitable for the estimation of true storage time of fish regardless of the radiation dose applied. 69 RESULTS OBTAINED In the case of trout it was shown that Q-values calculated from the impedance at frequencies of 16 and 100 kHz were useful for the estimation of the true storage time. The Q-values from impedances at 1 and 16 kHz were found to permit the estimation of doses of 200 krad and higher if true storage times were known. This method could also be applied to seafish. However, due to the inherent biological variations, conclusions from measure- ments obtained on a single fish were not reliable. Attempt to lower the threshold of detection to doses below 200 krad were not successful due to biological variations in the fish. CONCLUSIONS The application of a modified version of the 'Fish-tester' at 3 frequen- cies (1,16 and 100 kHz) was found to detect irradiation treatments at doses of 200 krad and higher. The method was also found to lend itself to auto- mation and to the evaluation of large numbers of fish within a reasonable time. However, a final evaluation of the applicability of the method would have to await introduction of large-scale fish irradiation. PAPER PUBLISHED ON WORK DONE UNDER THE CONTRACT EHLERMANN, D., The possible identification of irradiation treatment of fish by means of electrical (AC) resistance measurement, J. Food Sei. 37 (1972) 561. 70 RESEARCH CONTRACT No. 1070 Summary of final report IAEA-R-931-F TITLE Cell count reduction in seasoning, particularly in ground paprika, by radiation treatment (part of a co-ordinated program of research on the shelf- life extension of irradiated fruits and vegetables). RESEARCH INSTITUTION Department of Microbiology, Central Food Research Institute, Budapest, Hungary. PRINCIPAL SCIENTIFIC INVESTIGATOR J. Farkas. PERIOD OF CONTRACT 1 October 1970 - 30 September 1973. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT Spices and mixed seasonings are often heavily contaminated with micro- organisms, which may occasionally include pathogenic species. Heat treat- ment, which ensures microbial stability of the products, is not recommend- able as it has been shown to invoke detrimental changes in the spices relative to their nutritional and sensory values. For this reason the food industry has turned to the use of spice extracts or to gassing with ethylene or pro- pylene oxide. In the case of spice extracts their flavour qualities are con- sidered inferior to that of whole or ground seasonings, whilst fumigation sterilization is not effective in killing bacteria and is inseparable from the danger of chemical residues. Irradiation has been recognized as an efficient physical decontaminating method for spices and seasonings. High radiation doses were demonstrated to effect sterilization of the seasonings. The following investigations were undertaken to study the effects of low-dose radiation treatment on seasonings, with particular reference to ground paprika. EXPERIMENTAL METHODS Radiation treatments used in the investigation were done from 137Cs and 60Co sources, X-ray apparatus, and a Van de Graaff electron accelerator. Viable cell counts in ground paprika treated with radiation doses of 0-1600 krad were determined by plating methods and by the dilution technique. Sulphuric acid solutions and various saturated salt solutions were used to control and to set the equilibrium relative humidity in the samples. 71 Investigations relating to the establishment of disinfesting radiation doses for the various developmental stages of Plodia interpunctella were undertaken. Insects were reared on a synthetic medium composed of ground corn, ground wheat, bakers yeast, honey and glycerol, as well as ground paprika medium. Each developmental stage of the insect received doses of 5,17, 35 and 70 krad and was later placed on the growth medium. Control insects were similarly handled with the exception of radiation treatment. To study the effects of various kinds of ionizing radiation in the decon- tamination of certain seasonings and additives used in the canning and meat industry, seasoning-containing brawn and canned pork liver paste samples were subjected to various radiation doses varying from 0-1500 krad. In addition, canned liver-paste samples were exposed to various heat treat- ments, the sterilization equivalents of which were FQ = 13. 2, 1. 47, and 0. 14, respectively. Moreover, the effect of packaging materials and storage temperatures on irradiated paprika was studied. The paprika used was 9. 2% water con- tent. It was packaged in various packaging materials, including conventional red paper pouches, aluminium containers loosely filled under aerobic con- ditions, aluminium containers compactly filled under aerobic conditions, aluminium containers filled under N2 flow, polyester bags and polyethylene bags. Studies aimed at finding a method to detect radiation treatment in ground paprika were also undertaken. This was done by investigating the changes induced by irradiation in the paprika contents of carbohydrates and carbonyl compounds. In addition, the concentration of free radicals formed upon irradiation of the product was determined and their breakdown was followed as a function of storage time and moisture content of the spice by using an electron spin resonance spectrometer. RESULTS OBTAINED It was observed that radiation treatment of ground seasoning paprika at a dose of 300-400 krad effected a reduction of 99. 0-99. 99% of the viable cell count with no detrimental effects on either the water and pigment contents, colour or organoleptic properties of the product. A dose in the range of 1. 5-2. 0 Mrad was found to produce sterility of the seasoning. The radiation sensitivity of microbial flora of the ground paprika in the equilib- rium relative humidity (ERH) range of 10-90% was noted as not affected by fluctuations in ERH of paprika occurring in commercial practice. Following 4 months' storage at 52% relative humidity — and appropriate storage conditions industrially _ the total bacterial count was found to be 4. 3x10 /g of the irradiated spice. This value was five log cycles lower than that of untreated samples stored under similar conditions for the same period of time. The value obtained for irradiated spices was also below the 103/g value considered acceptable for sterilized seasonings. It was further established that surviving microbial flora of irradiated ground paprika did not propagate to an undesirable extent even under humid storage conditions. Surviving microbial flora of the radiation-treated seasonings were tested for their heat and salt sensitivity in comparison with untreated microbial flora. Results indicated that the heat and salt tolerance of the surviving microbial flora of the irradiated seasonings was lower than that contained in untreated samples. 72 The viable cell count of brawn samples prepared with treated seasonings was lower than in samples prepared with untreated samples. The use of irradiated seasoning in brawn reduced the heat treatment currently applied in industry to about half. Moreover, incorporation of radappertized season- ings in the preparation of pork liver paste reduced heat treatment used by industry to 1/6 and effectively achieved sterility of the product, even with respect to Clostridium botulinum. It was found that infestation of spices with Plodia interpunctella could be curbed by disinfesting radiation doses for the various developmental stages of the insect. Radiation doses of 40 krad were found sufficient to achieve disinfestation when the seasonings contained only eggs or very young larvae of the insect. Where the various developmental stages of the insects were present, a dose of 70 krad was found adequate. Definite changes in carbonyl compounds extracted from irradiated seasonings, suggestive of irradiation treatment, were not noted. Likewise, derivatography failed to yield unequivocal alterations. However, on the basis of the size of ESR, irradiated ground paprika ( > 0. 5 Mrad) was distinguishable from untreated samples during the first 2-3 weeks after irradiation only. CONCLUSIONS On the basis of these experiments, it appeared that decontamination by irradiation of the seasonings would be technologically feasible. Besides, use of irradiated seasonings would permit heat treatment to be reduced signifi- cantly and the quality of the product would be better than that at present available. PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACT FARKAS, J., "Methods for the determination of the number of bacterial spores" (in Hungarian), Elelmiszerv. Kbzlem. 17 (1971) 183-90. FARKAS, J., BECZNER, J., INCZE, K., "Feasibility of irradiation of spices with special reference to paprika", Radiation Preservation of Food (Proc. Symp. Bombay, 1972), IAEA, Vienna (1973) 389-402. FARKAS, J., "Radurization and radicidation of spices", Aspects of the Application of Food Irradiation in Developing Countries (Proc. Panel Bombay, 1972), IAEA, Vienna (1973) 43-59. BECZNER, J., FARKAS, J., Investigations into the radioresistance of Plodia interpunctella (Hiibner), Acta Phytopathol. Acad. Sei. Hung, (in press). BECZNER, J., FARKAS, J., Kisérl. K'ozlem. (in press). BECZNER, J., FARKAS, J., WATTERICH, A., BUDA, B., KISS, I., "Experiments into identification of irradiated ground paprika", Coll. Identification of Irradiated Foodstuffs, Karlsruhe, 1973. 73 RESEARCH AGREEMENT No. 974 Summary of final report IAEA-R-974-F TITLE Irradiation of dehydrated fruits (figs, prunes, raisins, etc.) at disin- festation doses: chemical and microbiological aspects (part of a co-ordinated program of research on the shelf-life extension of irradiated fruits and vegetables. RESEARCH INSTITUTION Comitato Nazionale per 1' Energia Nucleare, Centro di Studi Nucleari della Casaccia, Rome, Italy. PRINCIPAL SCIENTIFIC INVESTIGATOR M. Belli-Donini. PERIOD OF AGREEMENT 1 January 1971 - 30 April 1973 SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT Dehydrated fruits, because of their adequate contents of carbohydrates, mineral salts and vitamins, are considered of high nutritive value. However, there are some major preservation problems encountered in their storage. Among these problems is disinfestation of lepidopterous insects, which often infest these fruits. It has been demonstrated that low-dose radiation treat- ment is effective for the control of Lepidoptera. In vitro experiments have shown that doses of 30 krad resulted in almost total sterility of Ephestia insects, whilst at a dose of 60 krad the insects were observed to be com- pletely sterile. Studies relative to the effect of irradiation on the chemical constituents and microflora of dehydrated figs and prunes were undertaken. EXPERIMENTAL METHODS Dehydrated figs (sun dried and packed, sun dried and sulphate treated and then packed, and baked almond-containing figs) were irradiated at doses of 30, 60, 300 and 600 krad, respectively. Likewise, packed dehydrated prunes were treated with doses of 60, 300 and 600 krad. All radiation treatments were made at a temperature of 20°C using gamma radiation from fio a Co source. Postirradiation storage took place at ambient temperature in aerated glass boxes for controlling insect infestation. Assessment for dry weight, total sugars, reducing sugars, vitamins Bj, B2, B-carotene as well as determination of bacterial loads and their concen- trations in the irradiated fig and prune samples were carried out immedi- 74 ately after irradiation and at periodical intervals during storage. Similar evaluations were run on non-irradiated dehydrated figs and prunes for comparison. RESULTS OBTAINED It was noted that no substantial differences were observed with regard to the water content in irradiated figs compared to non-irradiated samples. Moreover, it was found that radiation treatment of the dehydrated fruit did not provoke any changes in either the total sugar content or in the reducing sugars. It was further noted that radiation treatment of dehydrated figs with doses up to 300 krad had no effect on the concentration of vitamin Bj, while a noticeable decrease was observed in samples treated with doses above 600 krad. At the former dose range, however, no variations were observed in vitamin B2 content of the figs so treated. The total bacterial counts in irradiated figs were observed to decrease in proportion to the radiation dose applied, albeit no differences were noted between irradiated and non-irradiated figs with respect to mould and yeast counts. No Lepidoptera or Coleoptera infestation was encountered in irra- diated figs stored up to 8 months. This was in contrast to control samples, which were found infested at the end of the storage period. In the case of dehydrated prunes it was noted that irradiation had no detrimental effects on the B-carotene content of the fruit. The effect of irradiation on bacterial counts in prunes was not investigated as their pre- sence in this product is negligible. CONCLUSIONS Radiation treatment of dehydrated figs and prunes for disinfestation against insects of the genus Ephestia has been shown to be technically feasible at a dose of 300 krad. At this dose level, no changes in the carbohydrate or vitamin content of the fruits were observed. Furthermore, the total bacterial counts in irradiated figs were noted to be greatly reduced. 75 INDUSTRY RESEARCH CONTRACT No. 870 Summary of final report IAEA-R-870-F TITLE Wood-polymer combinations using gamma radiation. RESEARCH INSTITUTION Department of Chemistry, College of Science, University of Baghdad, Adamiya, Baghdad, Iraq. PRINCIPAL SCIENTIFIC INVESTIGATOR M. F. Mayahi. PERIOD OF CONTRACT 1 January 1970 - 31 May 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT Methyl methacrylate or an unsaturated polyester-styrene mixture was used in the formation of wood-polymer combinations with date palms, bamboo or Populus euphretica to evaluate the feasibilities for these composites as substitutes for wood. EXPERIMENTAL METHODS The following variations of fibre materials were used in the investiga- tion: palm stem shavings; palm leaf strips; palm stem shreds; palm stem, 0. 5x3 x6 cm; palm stem washed with IN NaOH solution; bamboo shreds; bamboo strips; and Populus euphretica, 0.5x4x6 cm. The raw material was impregnated or mixed with either methyl meth- acrylate or an unsaturated polyester-styrene mixture and then irradiated with gamma rays from a 60Co source to a total dosage of 2 to 7 Mrad. After the removal of unreacted monomer the resulting mixture was weighed to deter- mine the polymer content in the composite. Some additives such as formaldehyde, carbon tetrachloride, eerie sulphate, ferric chloride, cobalt chloride and sodium silicate, were tested to see whether the inhibitive effect of lignins in the date palms could be suppressed. Shredded palm stem was mixed with an unsaturated polyester- styrene mixture and pressed under a pressure of 1500 lb/in2 before irradiation. 77 RESULTS OBTAINED AND CONCLUSIONS Gamma-ray induced polymerization of either methyl methacrylate or an unsaturated polyester-styrene mixture in date palms was strongly inhibited by the high lignin content present in date palms. No additive was found useful to prevent the inhibitive effect of lignin on polymerization. Prior washing of palm stems with lîi NaOH solution removed a part of the lignins, even so a high dosage of 7 Mrad was required for effective polymerization. The composite contained 8-13% polymeric substances. Premixing monomer with shredded palm stems followed by pressing and irradiation, produced better results than those from the impregnation method. In a comparative study for the preparation of wood-plastic combinations, Populus euphratica, which contains little lignins, was impregnated with an unsaturated polyester-styrene mixture and irradiated. The composite con- tained 27% polymer after a total dosage of 2 Mrad. Similarly, in the case of methyl methacrylate the composite contained about 10% polymer. Date palm leaves or bamboo strips were mixed with methyl methacrylate to form a mixture containing 42. 8% of monomer. Irradiation of this mixture to a total dose of 2 Mrad gave a composite with sufficient water resistance and abrasion resistance. PAPER PUBLISHED ON WORK DONE UNDER THE CONTRACT MAYAHI, M.F., NOFAN, A.A., Polymerization of methyl methacrylate in bamboo and date palm leaves by gamma radiation, Bull. Coll. Sei. (Baghdad) 14 (in press). 78 RESEARCH CONTRACT No. 1070 Summary of final report IAEA-R-1020-F TITLE Application of radioactivation to the determination of trace quantities of gold in rocks, water and plants (part of a co-ordinated program on the use of activation analysis in geochemical and geobotanical prospecting for ores and minerals). RESEARCH INSTITUTION Geological Institute, Department of Nuclear Geology, Bucharest, Romania. PRINCIPAL SCIENTIFIC INVESTIGATOR Maria Lemne, PERIOD OF CONTRACT 1 July 1971 - 30 June 1973. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT In geological sciences information on trace elements in minerals, rocks and other geologic materials is highly valuable, not only from the point of view of fundamental research, but also because it may yield highly useful inferences in respect of the occurrence of mineral deposits. The trace elements approach is nowadays becoming more widely used in geochemical explorations, especially when the search is for precious and rare metals. In this work the trace contents of gold in samples of rocks, waters and plants collected from four selected areas were studied, with an aim to find some correlations between the gold contents in these geologic materials. Neutron activation analysis (NAA) was employed as the main analytical technique in the study. EXPERIMENTAL METHODS From mining records and previous knowledge in mineralogy three of the selected areas could be classified as known gold-bearing zones and these are designated as Zone A, B and C. The fourth has been known to be free from gold mineralization and designated as sterile Zone D. All four areas are similar in their petrography, viz. they are built up from volcanic rocks having andesites as the main composition. The three gold-bearing zones are, however, different in their geology. By choice, the sterile Zone D is, in general, similar to the gold-bearing Zone A both in geology and petro- graphy. Also, one or more of the main plant species characterizing the vegetation of Zone A, B and C were present in Zone D. 79 Both methods of instrumental NAA and NAA with radiochemical separa- tions were evaluated for determining trace amount of gold in some rock samples. The requirement for high sensitivity together with the limited capability of the available gamma-spectrometry system (as imposed by the use of a Nal detector and an 800-channel analyser) led to the final selection of a destructive method for all three types of samples investigated. The method involved the dissolution of irradiated samples in aqua regia and the extraction of gold by an ion exchange technique. The chemical yield of the separation was reported to be 80-9 5%. The sensitivities of the method for gold in rocks, waters and plants were respectively 0. 5, 0. 1 and 0. 1 ng/g and the precisions in all cases were ± 5%. RESULTS OBTAINED Comparison of the results of rock and plant analyses indicated that the variation of gold in plants among the four investigated zones followed the order of that in rocks. Gold contents of water were studied only in the sterile zone (D) and in the one gold-bearing zone, which is similar to it both in petrography and geology (viz. Zone A). Concentrations of gold in waters in the sterile zone and in the hydrozone upstream from the gold vein appeared to be normal (below 0. 034 jug/litre). In crossing the hydrozone along the vein the gold contents in seepage water increased sharply by an order of magnitude around several decades (0. 128 to 0.919 ,ug/litre). The gold values became lower again downstream of the vein, but remained significantly above normal for a distance of over 800 m (0. 034 to 0. 619 ,ug/litre). CONCLUSIONS Neutron activation analysis has proven useful in geobotanical and hydro- geological investigations. Radiochemical separations were found necessary in this particular case because of the requirement for high sensitivity of the method for the element of interest. Some plants were identified as useful gold indicators, e. g. Fagus silvatica, Luzula sp.,Festuca rubra, Carex remonta, Rübus hirtus and some species of mosses (Polystichum sp., Vaccinium vit i s _ idaea and Hyco- podium clavatum ). Analysis of surface and seepage waters could provide useful information in the search for vein-type gold deposits. However, atmospheric precipita- tion may be an important factor in the variation in the gold content in waters and must be taken into account. 80 MEDICINE RESEARCH CONTRACT No. 672 Summary of final report IAEA-R-672-F TITLE Applications of radioimmunoassay techniques in growth hormone studies in undernourished children and adolescents with retarded growth. RESEARCH INSTITUTION University of Chile, Faculty of Medicine, Santiago, Chile. PRINCIPAL SCIENTIFIC INVESTIGATOR J. Litvak. PERIOD OF CONTRACT 15 December 1968 - 31 August 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT Malnutrition in early childhood is responsible for marked differences in growth rate between populations of developed and developing areas. A large spectrum of nutritional disturbances is found in such areas involving different degrees of protein, vitamin and caloric deficiency. Two distinct clinical entities can be identified: kwashiorkor - due mainly to protein deficiency — and marasmus caused by a combined deficiency of protein and calories. The role of the pituitary gland in malnutrition is incompletely understood. Aspects such as pituitary reserve and secretion of growth hormone (GH) in children and adolescents with short stature were investigated in the studies reported here. Radioimmunoassay was used for the measurement of GH levels in plasma. EXPERIMENTAL METHODS Eleven patients (4 males, 7 females) ranging from 7 to 21 years of age and referred to the hospital for their short stature were selected for studies at the Metabolic Unit of the University of Chile Clinical Hospital. Six of the patients were considered to have been affected by malnutrition at some earlier stage in their lives on the basis of their dietary habits and slow rate of growth, although they did not show clinical signs of malnutrition. Two patients had histories of protein-caloric malnutrition during their first two years of life and mild malnutrition from then onwards. The remaining three patients were identified as suffering from coeliac 81 disease. Nine well-nourished children and adolescents ranging from 4 to 19 years of age were used as controls. X-ray examinations of hand and wrist were performed on all subjects for determination of bone age and X-ray examination of the skull was also performed. Laboratory examinations included measurements of calcium, phosphate, cholesterol, electrolytes, sugar, serum proteins and A/G index in blood and measurements of calcium, phosphate and hydroxyproline excretion in urine. Evaluation of the functional state of the pituitary-adrenal axis was performed by measurement of hydroxycorticosteroid and 17-ketosteroid excretion before and after stimulation. Thyroid function was assessed by means of radioiodine uptake measurements and of basal metabolic rate measurements. Serum GH levels were determined by double antibody radioimmunoassay. GH secretion was measured during insulin-induced hypoglycaemia. In three of the patients an arginine infusion test was also performed. RESULTS OBTAINED AND CONCLUSIONS No significant differences in the results of tests performed were found between the two groups studied. All the patients showed normal GH levels and adequate response to the stimulation tests applied. It was concluded that pituitary function, especially the secretion of GH was normal in the group of patients studied. The hypothesis is advanced that growth retardation in malnourished children is not due to deficiency in GH secretion. PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACT YOULTON, R., RIESCO, J. , LITVAK, J. , ZLATAR, N. , Análisis de algunos problemas del método radio- inmunológie para la medición de hormona de crecimiento, Rev. Med. Chile 99 (1972) 572. YOULTON, R., RIESCO, J. , LITVAK, J. , ZLATAR, N.', Serum growth hormone and growth activity in children and adolescents with present or past malnutrition. Am. J. Clin. Nutrition 25 (1972) 1179. 82 RESEARCH CONTRACT No. 1070 Summary of final report IAEA-R-732-F TITLE Double-isotope techniques for the study of the mechanisms regulating aldosterone secretion and biosynthesis in experimental and clinical conditions associated with hyperaldosteronism. RESEARCH INSTITUTION Department of Physiology and Biophysics, School of Medicine, University of Chile, Santiago, Chile. PRINCIPAL SCIENTIFIC INVESTIGATOR E.T. Marusic. PERIOD OF CONTRACT 15 December 1968 - 14 December 1971. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT Because of the importance of aldosterone in the maintenance of body electrolyte and fluid balance, much attention is at present being devoted to studies concerning the mechanism and factors affecting its biosynthesis. Until recently such studies were very difficult because of the lack of a reliable and reproducible technique for measuring hormones in biological materials. The introduction of the double-isotope method has brought a considerable amount of progress not only to basic research in this field, but also to clinical diagnosis and investigation. The purpose of this investigation was to set up the double-isotope method for the measurement of aldosterone and to study the mechanisms regulating the biosynthesis of the hormone. The effect of sodium depletion and the action of the renin-angiotensin system on the biosynthetic steps leading to aldosterone were to be studied in particular. EXPERIMENTAL METHODS The basis of the studies carried out was the determination of the conversion rate of corticosterone to aldosterone during incubation of a mitochondrial system in the presence of 3H-labelled corticosterone. After extraction the amount of tracer representing newly synthesized aldosterone was measured. Correction for losses in the extraction procedure was made possible by the addition of trace amounts of 14C-labelled aldosterone before the extraction procedure took place. The adrenal glands were removed from dogs subjected to various experimental conditions, such as: (a) sodium depletion; (b) acute angiotensin II and renin infusion of the 83 adrenal glands of hypophysectomized and bilaterally nephrectomized animals; and (c) chronic experiments in intact and hypophysectomized animals receiving daily injections of dog renin. Contra-lateral glands provided the controls for individual animals. Glands infused with saline provided controls for differences between right and left glands in the measurement of the conversion rate of corticosterone to aldosterone. The mitochondrial fraction was obtained by differential centrifugation of adrenal gland homogenates. In the case of chronic experiments measurements of aldosterone secretion rate was performed by the double-radioisotope technique and of Cortisol secretion by fluorimetry. RESULTS AND CONCLUSIONS The results obtained indicate that the acute infusion of adrenal glands with angiotensin II has no effect on the conversion of corticosterone to aldosterone in the mitochondrial incubation system. However, it was demonstrated that the prolonged administration of renin causes an increase of the conversion of corticosterone to aldosterone in the mitochondrial system in the case of glands from hypophysectomized dogs. This effect is similar to that obtained with sodium-depleted animals. Based on the results obtained, it is postulated that angiotensin plays a double role in the biosynthesis of aldosterone. It would stimulate the initial steps, i. e. the conversion of cholesterol to pregnenolone under 'acute' conditions, while 'chronic angiotensin' would also increase the rate of the last steps of aldosterone biosynthesis. PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACT AGUILERA, G, , MARUSIC, E,T., Mecanismos que regulan la biosfntesis de aldosterona durante la deplecióndosodio, Rev. Med. Chile 98 (1970) 850. AGUILERA, G., MARUSIC, E. T., Role of the renin-angiotensin system in the biosynthesis of aldosterone, Endocrinology 89 (1971) 1524. AGUILERA, G., MARUSIC, E. T., LITVAK, J., IBANEZ, C., TRAVELLA, D., Experiencia en el montaje de la técnica doble isotópica para la determinación de aldosterona en orina, Rev. Med. Chile 100 (1972) 167. MARUSIC, E. T., WHITE, A., AEDO, A.R., Oxidative reactions in the formation of an aldehyde group in the biosynthesis of aldosterone, Arch. Biochem. Biophys. 157 (1973) 320. MARUSIC, E. T., GALLI, S., AGUILERA, G., "Control of aldosterone biosynthesis", Proc. 4th Con gr. Endocr., Washington (1972). 84 RESEARCH CONTRACT No. 1070 Summary of final report IAEA-R-762-F TITLE Development of new radiopharmaceuticals. RESEARCH INSTITUTION Bhabha Atomic Research Centre, Tata Memorial Hospital, Bombay, India. PRINCIPAL SCIENTIFIC INVESTIGATOR R.D. Ganatra; later S. M. Sharma. PERIOD OF CONTRACT 1 August 1969 - 30 November 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT Advances in nuclear medicine may result from the development of new instruments and techniques or from the development of new radio- pharmaceuticals. New radiopharmaceuticals developed in recent years have revolutionized nuclear medicine. In particular, the development and testing of radiopharmaceuticals labelled with short-lived radionuclides produced by generators, and tumour-localizing radiopharmaceuticals are a very promising field of study. Another development during recent years is the wide-scale acceptance of in vitro assay procedures, in particular radioimmunoassay techniques. EXPERIMENTAL METHODS The work under this contract consisted of: (1) development of new radiopharmaceuticals; (2) new applications of currently available radio- pharmaceuticals; (3) uses of generator-produced radionuclides; and (4) preparation of labelled compounds for in vitro assay techniques. Work on 131I-synkol and its analogues as possible tumour-scanning agents was carried out. The distribution of miscellaneous labelled compounds (131I-berberine as a possible pancreas-scanning agent; 203j-jg- hydroxymercuryfluorescein as a possible myocardial and tumour-scanning agent; 131I-iodopropamide as a possible pancreas-scanning agent; 203jjg- methimazole as a possible adrenal-scanning agent; and 131I-T4 and -T3 as a possible liver-scanning agent) in the body tissues was studied after administration by various routes. The distribution of 51Cr-chromic chloride and 51Cr-chromic citrate was compared to that obtained with67Ga- gallium citrate and 113mIn-indium chloride. Uses of 131I-T3 and 99mTc as labels for red cells were explored. An attempt was made to use lysolecithin 85 for denaturing red cells. Scintigraphic procedures with a gamma camera based on the use of generator-produced radionuclides (113mIn and 99mTc) were introduced into clinical routine. Human growth hormone (HGH) levels in plasma were also studied in marasmic children by radioimmunoassay with 125I-HGH. RESULTS OBTAINED The selective concentration in tumours appeared to be most favourable in the case of 131I-synkol. It was not possible to obtain good tumour scans with 131I-synkavit. Distribution studies failed to show any selective localization of 131I-berberine and 131I-iodopropamide in the pancreas. The accumulation of 203Hg-hydroxymercuryfluorescein in infarcted myocardial areas was not high enough for delineating the infarction by scintigraphy, but its concentration in tumours was sufficiently high to visualize by scintigraphy. The distribution pattern of 203Hg-hydroxymercuryfluorescein was similar to that of 203Hg-Neohydrin and 203Hg-mercuric nitrate. The distribution studies of 203Hg-labelled analogue of methimazole failed to show preferential localization in the adrenal gland. It was possible to obtain liver scans after oral or parenteral administration of 131I-T4 and 131I-T3. In the form of 51Cr-chromic chloride, 51Cr bound to plasma trans- ferrin in vitro, and the distribution of 51Cr-chromic chloride appeared to be similar to that of 67Ga-gallium and 113mIn-indium chloride. Increased concentration of 113mIn-indium citrate and 51Cr-chromic citrate was shown in fractured areas of the bone.131I-T3 and 3toTc labels for the red cells were not firm enough in vivo. It was found that only lysolecithin derived from human subjects gave some degree of denaturation of the red cells. 99mTc was obtained satisfactorily by methylethylketone (MEK) extraction from 99MO. It was felt that the 113rnin generator had distinct advantages in a developing country. In clinical experience of more than 1000 cases the single anterior view of a liver scan with a gamma camera was found to be as informative as multiple views in 97% of patients when H3min- colloid was used. Addition of a small quantity of ferric chloride allowed the formation of colloid without heating, which saved time. Distribution studies of 99mTc-polyphosphate did not confirm predominant localization in the bone, and better success was obtained with 99mTc-ethanehydroxydi- phosphate. The mean HGH level in marasmic children was significantly higher than the control value. No significant correlation between fasting blood sugar and fasting HGH levels was observed. Some cases showed no rise in HGH levels in response to insulin hypoglycaemia. This non- responsiveness was partially corrected by giving high protein diets for 4 to 6 weeks. PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACT SHARMA, S.M., PATEL, M.C., RAMANATHAN, P., GANATRA, R. D., BLAU, M., A new technique to denaturate red cells for spleen scanning, I. Nucl. Med. 11 (1970) 228. SEWATKAR, A.B., PATEL, M.C., SHARMA, S.M., GANATRA, R. D., QUINN, J. L., A simple and safer 113mIn colloid preparation for scanning of the liver, Intern. J. Appl. Radiât. 21 (1970) 36. 86 RAMANATHAN, P., GANATRA, R. D., DAULATRAM, K., SEN, P. K., BLAU, M., Uptake of 2í3Hg hydroxy-mercury-fluorescein in myocardial infarcts, J. Nucl. Med. 12 (1971) 641. GANATRA, R. D., "Preparation and control of '^-radiopharmaceuticals", Radiopharmaceuticals from Generator-Produced Radionuclides. (Proc. Panel Vienna, 1970), IAEA, Vienna (1971) 111. SAMUEL, A.M., DESHPANDE, U.R., Modified radioimmunoassay method of human growth hormone estimation, Indian J. Med. Res. (to be published). SAMUEL, A. M., DESHPANDE, U. R., Growth hormone levels in protein caloric malnutrition, J. Clin. Endocr. Metab. (to be published). SHARMA, S.M., QUINN, J. L. , "mTc brain scanning in intracerebellar haemorrhage, Arch. Neurosurgery (to be published). 87 RESEARCH CONTRACT No. 1070 Summary of final report IAEA-R-786-F TITLE Applications of radioisotope techniques in the clinical evaluation of cardiac patients during treatment and rehabilitation. RESEARCH INSTITUTION State Hospital for Cardiology, Balatonfüred, Hungary. PRINCIPAL SCIENTIFIC INVESTIGATOR M. Horváth. PERIOD OF CONTRACT 1 October 1969 - 30 November 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT In the clinical evaluation of cardiac patients during treatment and rehabilitation the combination of conventional methods for the investigation of cardiac and pulmonary function with methods involving the use of radio- isotopes has many advantages, offering a more complete insight into the progress of the patient and providing more reliable indications for cardiac surgery, rehabilitation exercises, carbon dioxide baths etc. A complete rehabilitation program based on clinical evaluation by such a combination of methods was developed under the contract. During the establishment of the methods in question a number of modifications and refinements were introduced therein. Results of certain investigations on normal subjects and on patients with various degrees of cardiac disability are included in this report. EXPERIMENTAL METHODS Selective radiocardiography was performed with saline solutions of 133Xe injected directly into the right heart through a Grandjean microcatheter, the counts registered by an external detector placed over the precordium being recorded digitally by means of a multichannel analyser operating in multiscaler mode. The data were subsequently subjected to analysis by computer. The rapid elimination of 133Xe in expired air allowed repeated radio- cardiographic investigations and cardiac output values obtained therein were shown to correlate well with values obtained by the dye dilution method. In serial investigations under workload 133Xe was injected at 1. 5-min intervals, the oxygen saturation in the arterial circulation of the ear being continuously recorded by oximetry and the pulse rate also continuously 88 recorded. After such repeated radiocardiographic investigations, the clearance of 133Xe from the upper right lung was registered by an external detector placed over this region. A radiocyclographic method similar to that described by Hoffmann and Kleine, whereby the radiocardiographic data could be further analysed to yield information about volume changes in the right heart during the cardiac cycle, was developed independently under the contract. This method depends on the averaging of counts recorded during corresponding portions of a number of successive cardiac cycles. By the use of 113mIn, which can be injected in larger amounts, in place of 133Xe, it was possible to obtain satisfactory results from data recorded over 200-250 cycles. Radiocyclo- graphy could also be performed under workload. The simultaneous recording of pressure in the right heart through a microcatheter added a further dimension to the method by permitting the investigation of volume/pressure relationships. Myocardial blood flow estimations were performed first with the positron-emitting radioisotope of rubidium 84Rb and subsequently, because of the high cost of 84Rb, with 86Rb, the uptake of the intra-arterially injected radioisotope by the myocardium being recorded by means of an external detector placed over the precordium. The selective investigation of myo- cardial blood flow was found to be possible, provided that a detector with a well-defined field of view was used. Investigations of regional pulmonary ventilation were performed with gaseous 133Xe administered by means of a spirometer, external detectors being used to record the distribution of the radioisotope in the lungs. Regional pulmonary perfusion was investigated by lung scintigraphy with a moving-detector scanner after the intravenous injection of macroaggregated 131I-labelled albumin. The effect of posture on regional perfusion was especially studied. , Muscle blood flow was estimated with saline solutions of 133Xe injected intramuscularly, the clearance of the radioisotope from the injection site being recorded by means of an external detector under conditions of rest or workload. Attempts were made to detect deep vein thrombosis in the lower legs by making measurements with an external detector" after the intravenous injection of 125I-labelled fibrinogen. The clearance of the radioisotope from the circulating blood was also followed by making measurements on blood samples. RESULTS OBTAINED ' In investigations on about 700 patients, about 560 underwent radio- cardiography, 50 radiocardiography under workload, 100 radiocyclography, 15 investigations of myocardial blood flow, 20 investigations of pulmonary perfusion (lung scintigraphy), 80 investigations of muscle blood flow and 60 investigations for the detection of deep vein thrombosis. Useful information about the progress of the invididual patient could be obtained from the results of repeated radiocardiographic investigations. Mitral status, for example, could be assessed in terms of the decreased slope of the descending limb of the partial left-heart radiocardiogram, a useful index for this purpose being the ratio of the halving times for the descending limbs of the left- and right-heart radiocardiogram s. This ratio 89 was elevated in mitral stenosis; after successful commissurotomy a return in its value towards normal was observed. Further useful information about the progress of the individual patient was provided by the results of investigations of pulmonary ventilation and perfusion. Radiocardiography under workload was valuable for the investigation of the circulatory reserve of patients with normal or near-normal radio- cardiograms at rest, particularly in screening such patients as to their suitability for rehabilitation exercise and assessing their subsequent progress. For screening a 4-min period of 50 W load was used; for assessing progress the load was increased to 80 W. Radiocyclography under workload showed promise as offering another means of screening patients as to their suitability for rehabilitation and assessing their progress, although the results obtained by this method have yet to be subjected to detailed analysis. Technical difficulties limited the usefulness of myocardial blood flow investigations in the context of the rehabilitation program. No differences in muscle blood flow at rest were observed between patients in the various categories studied, though investigations of muscle blood flow under workload were useful in the evaluation of patients with non-progressive or progressive dysbasia. The method used for the detection of deep vein thrombosis was found to give some false positive results, especially in patients with circulatory insufficiency. When localized uptake was observed in such patients, however, it persisted less long than when it was due to true thrombosis. CONCLUSIONS The work done under the contract constitutes a clear demonstration of the value of methods involving the use of radioisotopes in the clinical evaluation of cardiac patients, particularly during their treatment and rehabilitation. PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACT HORVATH, M. , A radioizotôp technika nyújtotta lehetbségek a légzésfunkciók vizsgálatában, Testnevelés-és Sportegészségügyi 10 (1960) 267. DEBRÖCZI, T., HORVÁTH, M., LUDVIGH, K., Die Wirkung von Bencyclan auf den Blutkreislauf der Wadenmuskulatur im akuten Versuch mit der 133Xe-Gewebs-Clearance-Methode, Arzneimittel-Forsch. 20 (1970) 1412. HORVÁTH, M., LUDVIGH, K. SÁRDY, J., HORVÁTH, M., CSONTOS, M., Regionális légzésfunkciós vizsgálatok Xe133 radioaktiv nemesgázzal, Tuberk. Tiidobetegségek 24 (1971) 12. HORVÁTH, M., Weiterentwicklung einer radiokardiographischen und oxymetrischen Methode zur Beurteilung von Herzpatienten in der Rehabilitation, Münch. Med. Wschr. 113 (1971) 1693. HORVÁTH, M., DEBRÖCZI, T., LUDVIGH, K., Complex cardiorespiratory investigations with minimal ergometric load for screening of patients in cardiac rehabilitation, Acta Med. Acad. Sei. Hung. 28 (1971) 37. HORVÁTH, M., Cél-automatikák és számítógépes adatfeldolgozási torekvések a Balatonfuredi Állami szívkórházban, Orv. Tech. 9 (1972) 6. HORVÁTH, M., LUDVIGH, K., KUTAS, V., Friss thrombus I125 fibrinogénnel való lokalizálhatóságár&l inszufficiens keringésü oedemás szfvbetegek alsó végtagján, Cardiol. Hung. 1 (1972) 37. 90 RESEARCH CONTRACT No. 1070 Summary of final report 1AEA-R-789-F TITLE Application of radioisotope techniques in studies of abnormalities in male sexual development. RESEARCH INSTITUTION División de Endocrinología, Hospital de Niños, Buenos Aires, Argentina. PRINCIPAL SCIENTIFIC INVESTIGATOR M. A. Rivarola. PERIOD OF CONTRACT 1 September 1969 - 30 September 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT The recent development of sensitive techniques for the measurement of steroid and protein hormones has made possible the study of new aspects of endocrine function in health and disease. Some of these techniques have been developed and applied to the study of testicular function before and during sexual maturation. It is known that the prepubertal testis is able to respond to chorionic gonadotropin stimulation. The possibility to measure this response by the determination of the change in concentration of testosterone in plasma gives a proof of this fact and permits the early detection of some abnormalities of testicular function. It is also known that androgens play a role in the stimulation of spermatogenesis. Little is known, however, about the mechanism of this effect. These two problems constitute the main concern of the studies reported here. EXPERIMENTAL METHODS Plasma testosterone concentration was measured by competitive binding and by radioimmunoassay. The metabolic clearance rate of testo- sterone and androstenione were determined by constant infusion. Aldo- sterone and Cortisol production rates were determined by isotope dilution. Plasma human growth hormone concentration was determined by radio- immunoassay. Testosterone metabolism in rat testis was studied by incubation of isolated seminiferous tubules and interstitial tissue with testosterone-14C. The products were isolated by thin layer and paper chromatography and identified by recrystallization. 91 RESULTS AND CONCLUSIONS Clinical studies In unilateral and bilateral cryptorchidism in prepubertal children plasma testosterone concentration increased from a mean of 25 ± 24 to 431 ± 96 and 32 9 ± 172 ng/100 ml respectively after five days of daily injections of human chorionic gonadotropin (800-5000 U/d). No changes were seen in bilateral anorchia. Children with male pseudo-hermaphroditism showed a definite though smaller response. Children with hypopituitarism had responses varying from none to normal. This group was further studied during prolonged administration of human chorionic gonadotropin (from 2 to 15 months). The same variable response was observed under this prolonged treatment. Whenever testicular tissue is present, a response to gonadotropin can always be detected in sexually immature subjects with the exception of some cases of hypopituitarism. Aldosterone secretion rate was found to be higher than normal in children with the simple virilizing form of congenital adrenal hyperplasia, particularly in cases with previous treatment. Experimental studies * The isolated seminiferous tubules of mature rats converted 24% of testosterone-14C into 5 o-androstan-3a, 17ß-diol-14C after 3 hours of incubation, while the main metabolite in the interstitial tissue was androst-4-en 3, 17 dione. The semiferous tubules of 20-day old rats were able to transform 60% of the precursor into andostandiol. In material prepared from rats less than 10 days of age, no metabolic activity was present but could be observed in seminiferous tubules from animals of 12 days of age, a maximum being observed when from those of 20 days and decreasing in material from older animals. The highest activity was observed at the meiotic stage of the development of the germinal epithelium. PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACT RIVAROLA, A., BERGADA, C. CULLEN, M., HCG stimulation test in prepubertal boys with cryptorchidism, in bilateral anorchia and in pseudohermaphroditism, J. Clin. Endocrinol. 31 (1970) 526. DAHL, V. , RIVAROLA, A., BERGADA, C., Aldosterone secretion rate in the simple virilizing form of congenital adrenal hyperplasia, J. Clin. Endocrinol. 34 (1972) 661. RIVAROLA, A., HEINRICH, J., PODESTA, J., deCHWOJNIK, F., BERGADA, C., Testicular function in hypopituitarism, Pediat. Res. _6_( 1972) 634. RIVAROLA, A., PODESTA, J., Metabolism of testosterone-14C by seminiferous tubules of mature rats: formation of 5a-androstan-3a, 17ß-diol-14C, Endocrinology 90 (1972) 618. RIVAROLA, A., PODESTA, J. , CHEMES, E., In vitro testosterone-14C metabolism by rat seminiferous tubules at different stages of development: formation of 5a-androstanediol at meiosis, Endocrinology 91 (1972) 537. SANDRINI NETO, R. , RIVAROLA, A., COCO, R., BERGADA, C., The testis in patients with abnormalities of sex differentiation. Histology and endocrine function, Acta. Endocrinol, (in press). 92 RESEARCH CONTRACT No. 1070 Summary of final report IAEA-R-814-F TITLE Development of radioimmunoassay techniques for the measurement of protein hormones. RESEARCH INSTITUTION National Atomic Energy Commission, Department of Chemistry, Bueonos Aires, Argentina. PRINCIPAL SCIENTIFIC INVESTIGATOR A.E.A. Mitta. PERIOD OF CONTRACT 1 November 1969 - 31 October 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT The studies performed relate to the establishment of radioimmuno- assay techniques for the measurement of various protein hormones. The techniques for labelling these hormones with radioiodine and purifying the products were studied and the best conditions for these procedures were established. The preparation of antisera was also undertaken. The reagents prepared by means of techniques developed under the contract are currently used in radioimmunoassays and in metabolic studies. EXPERIMENTAL METHODS Labelling procedures utilizing chloramine T as oxidant reagent were developed for the radioiodination of protein hormones. Preparations with specific activities ranging from 90 to 250 mCi/mg were obtained for the following hormones: insulin (pork, beef and human), human growth hormone (HGH), thyroid stimulating hormone (TSH), luteinizing hormone (LH), follicle stimulating hormone (FSH), human chorionic gonadotrophin (HCG), human placental lactogen (HPL), parathyroid hormone (PTH), adreno- corticotrophic hormone (ACTH), glucagon, gastrin and angiotensin I. Both 125rand 131I were used for labelling. Antisera were raised against insulin and HGH. A compartmental model of HGH distribution was derived from data generated by measurement of samples obtained after injection of *I-HGH in humans. The validation of radioimmunoassays performed with all reagents prepared under the contract was carried out and the assays established. 93 RESULTS OBTAINED AND CONCLUSIONS This contract was helpful in the development of radioimmunoassays in Argentina, with the utilization of local resources to the greatest extent possible. Medical institutions in Argentina and in neighbouring countries are already deriving great benefits from the use of reagents prepared at the research institution and also from the utilization of its facilities for training purposes. PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACT TEMPONE, A., QUIHILLALT, E. L., ARRIGHI, L., MITTA, A.E. A., Preparación de H. C. G. (hormona coríónica gonadotrófica) con 133I de alta actividad específica para su aplicación experimental y clínica, Rep.CNEA-317 (1972). ARATA, R. A., NUNEZ, G.N. de, MAUTALEN, C. A., MITTA, A.E. A., Preparación de parathormona 133I de alta actividad específica. Determinación por radioinmunoensayo de parathormona, Rep.CNEA-332 (1973). CARNEIRO, L. , CABREJAS, M. , WATANABE, T., BARMASCH, M., ALTSCHULER, N. , MITTA, A.E. A., DEGROSSI, O. J., Estudios "in vivo" de la hormona tiroestimulante humana, Rep. CNEA-339 (1973). BARMASCH, M., NUNES, G.N. de., ALTSCHULER, N., MITTA, A. E. A., Preparación de hormona tiroestimulante con 133I de alta actividad específica, Rep. CNEA-346 (1973). 94 RESEARCH CONTRACT No. 1070 Summary of final report IAEA-R-815-F TITLE Iron nutrition in Mexico (part of a joint IAEA/WHO co-ordinated research program on the use of radioisotopes in iron nutrition studies). RESEARCH INSTITUTION National Institute of Nutrition, Department of Nuclear Medicine, Mexico, D.F., Mexico. PRINCIPAL SCIENTIFIC INVESTIGATOR J.A. Maisterrena. PERIOD OF CONTRACT 1 December 1969 - 31 March 1973. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT Iron deficiency in man is a rather common condition characterized by inadequate haemoglobin and iron stores in the body. In advanced stages it is manifested as iron deficiency anaemia, which is attended by tiredness, reduced working capacity, and other symptoms. Iron deficiency results from low iron intake in the diet, low availability of the iron, or excessive losses from the body. The objective of this investigation was to examine the availability of iron in the Mexican diet as typically consumed by various segments of the population, especially those with less adequate nutrition. EXPERIMENTAL METHODS All subjects in whom iron absorption was investigated were first characterized as to their iron status by measurement of the haemoglobin concentration in the blood, the packed red cell volume, the iron concen- tration in the serum, and the transferrin saturation index. The per cent of the iron absorbed from the test meal was usually estimated with the aid of an 'extrinsic tag' of 59Fe and whole-body counting of the retained tracer. The extrinsic tag consisted of 3 ßCi of 59Fe added to and mixed in a component of the meal shortly before its consumption, a procedure that has been shown in other investigations to label with reason- able validity the non-haem component of the iron in the meal. Whole-body counting was performed in a shadow-shield scanning-geometry instrument, wherein the count rate attributable to the59Fe in the subject's body was measured by Nal(Tl) crystals above and below the reclining body as it passed between them. Each subject was measured before consuming the 95 tracer to determine the background count rate of his body, 3 hours after to determine the count rate attributable to 100% of the dose, and 15 days after to determine the count rate of that part of the dose that was absorbed. A small-scale experiment was also undertaken to validate the extrinsic tag method. Tortillas were prepared from maize whose native iron had been biologically labelled with 55Fe by growth of the plants in a nutrient solution containing this isotope. In addition, an extrinsic tag of 59Fe was added to the dough during its preparation. The amount of59Fe absorbed was determined by whole-body counting; the relative amount of 55Fe absorbed was determined by measuring, in a liquid scintillation counter, the 55Fe/59Fe activity ratio in a blood sample taken two weeks after adminis- tration of the tracers. RESULTS OBTAINED One group of 19 subjects in apparently good health was tested for absorption of iron from a breakfast typical of that consumed by the higher socio-economic class: 200 ml orange juice, 2 scrambled eggs, 2 slices of bread, black coffee with sugar. The 59Fe tracer was added as a solution to the orange juice. Mean absorption of the tracer was 21%. A second group of 16 subjects comparable to the first group was tested for iron absorption from a breakfast typical of that eaten by the lower socio-economic class: black beans, 2-4 maize tortillas, black coffee with sugar. The 59Fe tracer was mixed in the coffee. Mean absorption of the 59Fe was 8%. A third group of 18 subjects was tested on each of the two diets in turn. For the upper-class diet mean absorption was 30%, while for the lower- class diet it was 9%. A fourth group was used to test the effect of the addition of orange juice to the lower-class meal. The mean absorption from the breakfast with orange juice was 15%; without orange juice it was 3%. Finally, the test of the validity of the extrinsic tag method showed in 4 subjects that the absorption of the 'extrinsic tag' was 83 to 100% of that of the native maize iron. CONCLUSIONS The results show that iron absorption from the upper-class Mexican breakfast is substantially better than that from the lower-class breakfast, and suggest that the addition of orange juice to the lower-class breakfast nearly eliminates the difference. The methodology for investigating iron absorption has been established to allow further investigations under a wider variety of conditions. PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACT MURPHY, C. A., TOVAR, E. , MAISTERRENA, J.A., "Uso de un antropogammámetro clínico", 6th Reunión Anual. , Sociedad Mexicana de Medicina Nucleai (1972) 188. 96 MAISTERRENA, J. A., TOVAR, E. , MURPHY, C. A., "Retención de hierro radioactivo', 6th Reunión Anual., Sociedad Mexicana de Medicina Nuclear (1972) 197. MAISTERRENA, J.A., TOVAR, E., MURPHY, C. A., 9th Int. Cong. Nutrition, Mexico (1972) 124. MAISTERRENA, J. A., MURPHY, C. A., TOVAR, E., "Absorción de hierro en dos tipos de dietas'; 7th Reunión Anual., Sociedad Mexicana de Medicina Nuclear (in press). MAISTERRENA, J.A., TOVAR, E. , MURPHY, C.A., Rev. Invest. Clin. 25 (1973) 1. MAISTERRENA, J.A., TOVAR, E., MURPHY, C.A., Gac. Med. Mexico (in press). 97 RESEARCH CONTRACT No. 1070 Summary of final report IAEA-R-825-F TITLE The availability of foodstuff and supplemental iron from mixed diets based on wheat (part of a joint IAEA/WHO co-ordinated research program on the use of radioisotopes in iron nutrition studies). RESEARCH INSITUTION Department of Food Technology and Nutrition, American University of Beirut, Beirut, Lebanon. PRINCIPAL SCIENTIFIC INVESTIGATOR M.S. Mameesh; then H. Hallab; finally E. Pascoe. PERIOD OF CONTRACT 31 November 1969 - 31 March 1973. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT Iron deficiency is frequently observed in people of the Middle Eastern countries. It may, in general, be caused by inadequate dietary intake of iron, by low availability of the iron, by excessive losses from the body, or by a combination of these conditions. While consumption of iron-rich foods such as meat is low in this region, the quantitites of Arabic bread eaten are sufficient to contribute substantial amounts of iron to the diet. Unfortunately, however, the availability of this iron for absorption is rather low. This investigation focused upon two questions, namely (1) how much iron is absorbed from the various components of a typical mixed diet based primarily on wheat, and (2) is it possible to use Arabic bread asa vehicle for effectively increasing the amount of absorbable iron in the diet? EXPERIMENTAL METHODS The typical meal selected for study consisted of chicken meat, eggs, wheat bread and chickpeas. The iron in representative lots of these four foodstuffs was labelled with 55Fe, through intramuscular injection of a citrate solution into chickens and stem injection of a FeCl3 solution into wheat and chickpea plants during growth. The mass of iron and activity of 55Fe were determined in aliquots of each labelled foodstuff. The absorbability of iron contained in the various foodstuffs was investigated in professional blood donors, whose haematological status resembled that characteristic of iron deficiency anaemia. 98 The experimental design of the test program was as follows. On Day 1 blood was sampled to allow determination of haematological status. On Day 2 the labelled foodstuffs were administered to fasting subjects in such a manner as to test the absorbability of iron from a single food component when fed either as part of a mixed meal or in isolation by itself. Thus four groups of about 10 subjects each received the typical meal, a different single component being radioactive for each group. Further subjects received a single radioactive component by itself. On Day 3 each subject drank a solution of 5 mg iron, in the form of ferrous sulphate and labelled with 59Fe, accompanied by 0. 33 g ascorbic acid. On Day 14 a blood sample was collected from each subject and its content of 55Fe and59Fe was deter- mined, relative to the administered doses, by liquid scintillation counting. In the exploration of means to improve iron nutrition through enrich- ment of Arabic bread, several types of enrichment were tested. To bread dough of wheat flour (with a natural iron content of 2. 25 mg/100 g bread) were added FeClß, Fe-citrate, or FeS04 plus ascorbic acid. To bread dough made of 80% wheat flour and 20% chickpea flour (with a natural iron content of 5. 0 mg/100 g bread) were added FeCl3 plus ascorbic acid, FeS04 plus ascorbic acid, or nothing. The iron salt was labelled with59Fe, while the native iron in the flour was labelled with 55Fe. In all cases the supple- mental iron salt added 6. 7 mg iron/100 g bread. Eight to ten subjects were tested under each condition. RESULTS OBTAINED When each food component was eaten in isolation, iron incorporation into haemoglobin was found to average: 14% from chicken meat, 16% from eggs, 15% from wheat bread and 12% from chickpeas. When the foodstuff was eaten as a part of a mixed meal, the incorporation of iron into haemo- globin was: 10% from chicken meat, 2 5% from eggs, 11% from wheat bread and 8% from chickpeas. In the supplementation of wheat bread it appeared that FeCl3 and Fe- citrate suppressed the absorption of the native iron, but were themselves sufficiently available as to offer approximately twice as much absorbable iron as the unsupplemented bread. The FeS04 plus ascorbate, however, seemed to increase the absorption of native iron and the total amount of iron available was about 4 times that in unsupplemented bread. When 20% of the wheat flour in bread was replaced by chickpea flour, the available iron was found to be doubled. The highest iron absorption was observed for bread enriched with chickpea flour, FeS04 and ascorbic acid; the absorbable iron exceeded that from wheat bread alone by a factor of 15. CONCLUSIONS Absorption of iron from Arabic bread, chicken meat and chickpeas is approximately the same when these foodstuffs are eaten as a mixed meal as when they are eaten in isolation. In contrast, iron absorption from eggs appears to be greater when they are eaten as part of the mixed 99 meal than when eaten alone. Supplementation of Arabic bread with chickpea flour, added iron salts and vitamin C substantially increases the amount of iron available for absorption. PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACT APRAHAMIAN, S. , B1KHAZ1, G., MAMEESH, M.S., PASCOE, E., "Absorption of foodstuff iron in relation to blood hemoglobin in humans", Fourth Science Meeting, Lebanese Association for the Advance- ment of Science, Beirut, 1972 (Abstract). APRAHAMIAN, S., BIKHAZI, G., PASCOE, E. , "Iron absorption from Arabic bread supplemented with iron salts", Fourth Science Meeting, Lebanese Association for the Advancement of Science, Beirut, 1972 (Abstract). BIKHAZI, G. , MAMEESH, M. S., PASCOE, E., "The availability of foodstuff iron from a mixed diet based on wheat", Third Science Meeting, Lebanese Association for the Advancement of Science, Beirut, 1971 (Abstract), BIKHAZI, G.N., Iron Availability from Iron-fortified Arabic Bread and from a Mixed Diet based on Wheat, M. Sc. Thesis, American University of Beirut (1972). 100 RESEARCH CONTRACT No. 1070 Summary of final report IAEA-R-850-F TITLE Application of radioimmunoassay techniques in investigations of plasma insulin in Ugandans. RESEARCH INSTITUTION Makerere University Medical School, Kampala, Uganda. PRINCIPAL SCIENTIFIC INVESTIGATOR S. K. Kajubi. PERIOD OF CONTRACT 1 December 1969 - 30 November 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT Reliable physiological data on the levels of important hormones, such as those concerned with carbohydrate metabolism, in the Ugandan Africans were scanty until very recently. A few studies of plasma insulin con- centrations in the fasting state had been reported. Biological assay methods had been used in these studies, however, and it seemed desirable to repeat the studies using modern methods of assay. A peculiar type of diabetes characterized by chronic pancreatitis with calcification detectable on X-ray examination of the abdomen is very common in Uganda. This too had not been completely investigated, in spite of the fact that it might provide intriguing comparisons with other types of diabetes known today. It had been suggested by some workers that the cause of this chronic pancreatitis was childhood malnutrition, but no convincing evidence for this had yet been provided. It had been observed that the Ugandan diabetic on insulin therapy is particularly sensitive to exogenous insulin. The work performed under this contract aimed at the utilization of in vitro assay procedures based on the use of radioisotopes to provide some clarification of these different questions. EXPERIMENTAL METHODS Radioimmunoassay procedures for the measurement of plasma insulin and growth hormone (GH) by the double antibody technique were set up. Clinical studies were performed on healthy volunteers and hospital patients. Estimation of the beta cell mass of the pancreas was performed by stimu- lation with oral glucose, tolbutamide and glucagon. Experimental studies were carried out using dogs to investigate a possible correlation of pancreatic beta cell mass with age and body weight. 101 RESULTS OBTAINED AND CONCLUSIONS The results indicated that the fasting concentrations of plasma insulin in normal Ugandan Africans are in the same range as quoted in the literature for other areas of the world. The insulin secretory profiles after a glucose load in normals and in patients with pancreatic calcification showed the commonly found 'early' and 'late' rise patterns, the 'late' rise pattern suggesting the gene for diabetes. Not all patients with pancreatic calcifi- cation had either frank diabetes or the gene for this disease. No evidence was found to support the notion that childhood malnutrition predisposes to pancreatic disease (and hence diabetes) after it has been treated and cured. The beta cell mass of the pancreas was found to be reduced in patients with chronic pancreatic disease. While normal Ugandan Africans responded to insulin-induced hypoglycaemia by the adequate production of GH and Cortisol, those with chronic pancreatic disease produced insufficient quantities of GH. Studies on the sensitivity of normal Ugandan Africans to insulin showed that they develop a more profound hypoglycaemia than do Caucasians when challenged with standard doses of insulin. The result of the experimental studies on the correlation of the beta cell mass with age and weight showed a tendency to a modest increase in beta cell mass during the period from 2 to 6 months of age. No conclusion, however, can be drawn from these results. PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACT KAJUBI, S. K., Beta cell mass of the pancreas. Lancet 2 (1971) 438. KAJUBI, S.K. , Fasting insulin in Ugandan Africans, East Afr. Med. J. 48 (1971) 732. KAJUBI, S.K. , Serum insulin in Ugandan Africans, Afr. J. Med. Sei. 3 (1972) 169. KAJUBI, S.K. , The endocrine pancreas after kwashiorkor, Amer. J. Clin. Nutrition 25 (1972) 1140. KAJUBI, S.K. , Insulin-induced hypoglycaemia in Ugandan patients-with chronic pancreatic disease; some preliminary observations, Afr. J. Med. Sei. 4 (1973) 412. 102 RESEARCH CONTRACT No. 1070 Summary of final report IAEA-R-851-F TITLE Application of in vitro radioisotope techniques in studies on the endocrine status of the Nigerian. RESEARCH INSTITUTION Department of Chemical Pathology, University of Ibadan, Ibadan, Nigeria. PRINCIPAL SCIENTIFIC INVESTIGATOR B. Kwaku Adadevoh. PERIOD OF CONTRACT 1 December 1969 - 30 November 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT Laboratory data on the endocrine status of the Nigerian are not fully available, thus limiting the evaluation of the hormonal role in pathological states, particularly against the background of various endemic and nutritional problems. In vitro assay procedures, because they do not require administration of radioactivity, are very useful for obtaining such data, especially in the case of children. These procedures were thus used throughout the studies reported here. EXPERIMENTAL METHODS Insulin, human chorionic somatomammotropin (HPL) and oestradiol were determined by radioimmunoassay. Plasma Cortisol and tri-iodothironine (T3) were measured by saturation analysis. RESULTS OBTAINED AND CONCLUSIONS High fasting levels of insulin, which may be related to the high carbo- hydrate diet, were obtained in adults (22. 0 ± 1. 9 MU/ml), in pregnancy (18. 5 ± 0. 94 juU/ml) and in children (15. 6 ± 0. 71 /uU/ml). No increase in plasma insulin level was observed with age. A delayed maximum insulin response was observed after oral glucose load. The peripheral insulin response to three sulphonylureas parallelled their therapeutic potency, thus reflecting an adequate pancreatic response to these drugs following glucose challenge. The radioimmunoassay of plasma insulin was instrumen- tal in confirming the diagnosis in two cases of insulinoma. HPL levels in pregnancy ranged from 3.2 to 11.3 Mg/ml in the second trimester and from 103 9. 3 to 27. 1 Mg/ml in the third trimester. Problems with the radioimmuno- assay of oestradiol were encountered, probably due to low affinity of the rabbit antisera obtained by injection of oestradiol-succinyl-bovine serum albumin (batch R39/71/3 - Prof. Kellie, Middlesex Hospital, London) to the antigens employed, e. g. oestradiol, oestrone and testosterone. The results of plasma Cortisol binding tests performed with samples obtained during insulin hypoglycaemic stress suggested an increase in non-protein bound Cortisol at the height of the hypoglycaemic stress, before a maximum rise in plasma Cortisol occurred. A Sephadex T3-uptake test developed in the contractor's laboratory compared favourable with the Thyopac-3 T3-uptake test (Radiochemical Centre, Amersham), but the values obtained were low. By means of the in vitro procedures established, it -will also be possible to follow endocrine changes in kwashiorkor, control the use of contraceptives and measure the secretion of insulin in cases of lactose intolerance. PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACT ADADEVOH, B.K., Plasma Cortisol and Cortisol binding during insulin-induced hypoglycemic stress, Am. J. Med. Sei. 262 (1971) 39. ADADEVOH, B. K. , LUKANMBI, F. A. , Insulin levels in Nigerian adults, children and pregnant women, Horm. Metab. Res. 4 (1972) 136. ADADEVOH, B. K., FRANCIS, T. I., AJAYI, O. O.A. , Endocrine disorders in African children, Nig. Med. J. 2(1972) 2. ADADEVOH, B. K. , "Insulin secretion in Nigerians: Effect of oral glucose and response to hypoglycaemic sulphonylureas", VIII World Cong. Anatomic and Clinical Pathology, Munich (1972). ADADEVOH, B. K., "The mechanism of action of sulphonylurea antidiabetic agents", Proc. East African Medical Research Council Seminar on Use and Abuse of Drugs and Chemicals, 1973 (in press). ADADEVOH, B.K. , "A study of the incidence of hyponatriaemia and hypothyroidism amongst an African diabetic population", East African Medical Research Council Seminar on Use and Abuse of Drugs and Chemicals, 1973 (in press). 104 RESEARCH CONTRACT No. 1070 Summary of final report IAEA-R-858-F TITLE Studies of a radioactive gel diffusion technique and its application to immunological studies on African populations. RESEARCH INSTITUTION Institute of Biochemistry, World Health Organization International Reference Centre for Immunoglobulins, University of Lausanne, Lausanne, Switzerland. PRINCIPAL SCIENTIFIC INVESTIGATOR D. S. Rowe. PERIOD OF CONTRACT 1 January 1970 - 31 May 1972. RESEARCH CONTRACT No. 860 Summary of final report IAEA-R-860-F TITLE Studies of a radioactive gel diffusion technique and its applications to immunology. RESEARCH INSTITUTION Regional Research and Training Centre for Immunology, World Health Organization Immunological Research Centre, University of Ibadan, Ibadan, Nigeria. PRINCIPAL SCIENTIFIC INVESTIGATOR V. Houba. PERIOD OF CONTRACT 1 January 1970 - 31 December 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECTS The single radial diffusion method for the quantitative estimation of immunoglobulins and other soluble proteins in serum originally described by Mancini et al. is simple and convenient and gives reproducible results. 105 However, it is only suitable for estimations at protein concentrations down to about 10 Mg/ml. While estimations at concentrations down to as little as 1 ng/ml are possible by radioimmunoassay methods, the applicability of such methods is limited by the fact that they require labelled antigen preparations of high purity and specific activity. The modification of the single radial diffusion method due to Rowe, in which a radioactive tracer is used, permits estimations at concentrations down to about 100 ng/ml while retaining the simplicity and convenience of the original method. This modification may be particularly useful when intermediate sensitivity is needed, the more so since it involves the use of labelled antibody and does not require a labelled antigen preparation. The studies carried out under these contracts were directed in part towards the refinement of the radioactive single radial diffusion method and an assessment of its practical value, and in part towards its application in the investigation of various problems, relating especially to Africa. In the latter regard, particular attention was given to the use of the method for the estimation of immunoglobulin E, a human immunoglobulin which, whilst not normally present in serum at concentrations greater than 1 jug/ml in European subjects, has been reported present at much higher levels in certain African subjects. The reason for this finding is still not clear since antibodies of this type are usually associated with allergic reactions; it has been suggested, however, that the increased immunoglobulin E levels may be associated with helminthic and other infestations. Attention was also given to the use of the method for the estimation of immunoglobulins G and M bound in immune complexes deposited in body tissues. Such deposition has been shown to be important, for example, in the pathogenesis of nephropathies in malaria. EXPERIMENTAL METHODS The original radioactive single radial diffusion method described by Rowe is an 'indirect', two-step method in which the serum containing the immunoglobulin or other antigenic protein to be estimated is first allowed to react with unlabelled antibody incorporated into the agar gel medium of an immunoplate (first step). A zone of precipitated antigen-antibody complex forms, but is not visible at low antigen concentration. The plate is washed and then treated with radioiodine-labelled antibody to the first antibody (second step). This labelled antibody binds to the precipitated complex. The plate is again washed and the zone of the now radioactive complex delineated by autoradiography. A number of minor improvements, for example the substitution of agarose for agar in the gel medium, the use of more specific antisera, the substitution of 125I for 13 I as tracers, the removal of aggregates from the labelled antibody before use, and the use of improved washing procedures were introduced into this method as a result of studies carried out under the contracts. A 'direct', single-step modification of the method was also developed. In this modification, the antibody to the antigen to be estimated is itself labelled with radioiodine before incorporation into the agar gel medium. The serum is then allowed to react with the labelled antibody incorporated into the medium, the plate is washed and the zone of the already radioactive 106 precipitated complex delineated by autoradiography. This direct method offers a sensitivity similar to that of the indirect method, takes only 3 days as compared with 7-8 days for its completion and is more economical in materials since it requires no second antibody. Two extensions of the direct method were developed. The first of these makes possible its application in the estimation of immunoglobulins bound in immune complexes deposited in body tissues. This involves preliminary elution of the immune complexes by citric acid at pH 2. 7. The second makes possible the demonstration of immunoglobulin secretion by individual cells. This involves culture of the cells in question in the agarose gel medium containing the labelled antibody. RESULTS 1. Immunoglobulin E levels in the sera of African as compared with European subjects Estimations of immunoglobulin E levels in the sera of subjects in Ibadan and Lausanne performed under the contracts by means of either the indirect radioactive single radial diffusion method or its direct modification demonstrated the practical value of these methods and confirmed the higher levels of immunoglobulin E previously reported in the sera of African subjects. All of 100 blood donors in Lausanne had immunoglobulin E levels below 2000 units/ml; 39 of 177 blood donors in Ibadan had levels in excess of this value and 27 had levels even in excess of 10 000 units/ml. The reasons for this finding remain obscure, however. Observations on patients in Nigeria failed to suggest any association of the increased levels with schistosomiasis or onchocerciasis. Similar observations on patients in Tanzania failed to suggest any association with malaria. Some correlation of increased levels and the occurrence of Ascaris, Ancylostoma and other parasites in stools was observed in children in Ghana and adults in Nigeria. Increased levels were observed in cocoa bean workers in Nigeria suffering from various allergic symptoms. No significant differences were observed between levels in asthmatic children and matched controls in Ghana. 2. Immunoglobulin G and M levels in body tissues of patients with nephropathies associated with malaria Whilst the demonstration of immune complexes in the kidney tissue of patients with nephropathies by non-radioactive methods was possible only when a large portion of the kidney was available, the extension of the direct radioactive single radial diffusion method to the estimation of the immuno- globulins bound in immune complexes in tissues was shown to permit the estimation of immunoglobulin G and M levels in small biopsy specimens of kidney tissue of about 300 mg in mass. The limit of detection for immuno- globulin G was about 10 ng and that for immunoglobulin M about 50 ng. Studies were performed on 35 biopsy specimens, the maximum yield of immunoglobulins being about 1 ßg/g tissue. 107 3. Identification of immunoglobulin-releasing cells in human tonsillar tissue The extension of the direct radioactive single radial diffusion method to the demonstration of immunoglobulin secretion by individual cells was particularly utilized to study such secretion in human tonsillar tissue. A mean of 9. 3% of cells in suspensions prepared from such tissue were identified as actively secreting immunoglobulins. CONCLUSIONS The results obtained clearly demonstrated the increased sensitivity of the radioactive single radial diffusion method as compared with non- radioactive methods for the quantitative estimation of immunoglobulins and other soluble proteins. The direct modification of the original indirect method was shown to offer advantages of speed and economy without loss of sensitivity. Immunoglobulins bound in immune complexes in body tissues could be estimated by an extension of the direct method involving a preliminary elution procedure. Immunoglobulin secretion by individiual cells could be demonstrated by a second extention. Estimations of immunoglobulin E levels in African and European subjects confirmed the higher levels in the former already reported, though the reasons for this finding remain obscure. Estimations of immunoglobulin G and M levels in biopsy specimens of kidney tissue from patients with nephropathies associated with malaria confirmed the deposition of immune complexes in the kidneys of such patients. Immunoglobulin secretion by human tonsillar cells was demonstrated. The methods developed and used should find wide application in the detection and estimation of immunoglobulins and other soluble proteins in sera, tissues and other biological materials. PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACTS CORNILLE, R. , ROWE, D. S, , A radioactive antiserum in agar technique for the demonstration of immuno- globulin secretion by lymphoid cells, Clin, exp. Immunol. 8 (1971) 981. HQJDA, v., "Experience with the radioactive single radial diffusion technique for the estimation of immunoglobulins", Radioactive Tracers in Microbial Immunology (Proc. Panel Vienna, 1971), IAEA, Vienna (1972) 25. HOUBA, V., "The estimation of radioisotope techniques of minute amounts of immunoglobulins in immuno- complexes bound in tissue", Radioactive Tracers in Microbial Immunology (Proc. Panel Vienna, 1971), IAEA, Vienna (1972) 29. HOUBA, V., ROWE, D.S., Serum levels of immunoglublins in Africans (to be published). 108 RESEARCH CONTRACT No. 1070 Summary of final report IAEA-R-945-F TITLE The use of 59Fe-ferrioxamine in studies of the effect of the depot iron content of the body on the serum iron level in viral hepatitis. RESEARCH INSTITUTION 1 st Medical Clinic, University of Ege, Izmir, Turkey. PRINCIPAL SCIENTIFIC INVESTIGATOR M.A. Bölükoglu. PERIOD OF CONTRACT 1 September 1970 - 30 September 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT The findings that the serum iron concentration and serum transaminase level are usually elevated in viral hepatitis and usually normal in obstructive jaundice provide a convenient basis for differential diagnosis of these conditions. The serum iron concentration is not always elevated, however, in viral hepatitis. To investigate the possibility that a normal serum iron concentration in this disease may result from depressed iron stores due to iron deficiency, the differential ferrioxamine test of Fielding employing 59Fe-ferrioxamine was used to estimate chelatable body iron in normal subjects and in patients with viral hepatitis, as well as in patients with obstructive jaundice, liver cirrhosis, liver stasis and thalassaemia. EXPERIMENTAL METHODS The differential ferrioxamine test of Fielding was used to estimate chelatable body iron. The test is commenced at 11 a.m. The bladder is emptied and mixture of desferrioxamine and ferrioxamine labelled with 59Fe injected intravenously, the dosage being calculated according to body weight. A modified technique was used by the contractors for the preparation of this mixture since ferrioxamine was not available to them; this technique involved the addition of an appropriate amount of a solution of ferric chloride containing 59Fe to a solution of desferrioxamine. Following the injection, urine is collected for 6 hours and the total 59Fe and ferrioxamine contents of the pooled urine specimens are measured, the latter chemically by the method of Fielding and Brunström. If the urine contains bilirubin, this is first removed by the method of Barry and Carter. 109 The 59Fe content of the urine is a measure of the injected ferrioxamine excreted and is expressed as mg ferrioxamine (Fex). The ferrioxamine content, also expressed as mg ferrioxamine (Ft ), is a measure of the injected ferrioxamine excreted (Fex) plus that produced as a result of chelation of body iron in vivo by desferrioxamine and subsequently excreted (Fd). Hence Fd = Ft = Fex . Now it may readily be shown that the total amount of ferrioxamine produced as a result of chelation of body iron in vivo by desferrioxamine (Fv ) is given by F = FXFd where F is the amount of ferrioxamine injected. Fv is a convenient index of chelatable body iron and is conventionally expressed in Mg/kg body weight. Other procedures carried out, all by conventional methods, included the measurement of serum iron concentration, serum unsaturated binding concentration, serum unsaturated binding capacity, serum glutamate- oxaloacetate transaminase (SGOT), glutamate-pyruvate transaminase (SGPT) and alkaline phosphatase levels, and serum bilirubin concentration, as well as the zinc sulphate and thymol turbidity tests. RESULTS OBTAINED A total of 11 normal subjects and 90 patients were investigated. Of the 32 patients with viral hepatitis 7 had serum iron concentrations below 120 jug/100 ml and 25 had serum iron concentrations above 120 Mg/100 ml. The mean serum iron concentrations and Fv values of these sub-groups were 80. 7 ± 26. 9 and 184. 4 ± 44. 7 Mg/100 ml, and 737. 8 ± 320. 1 and 1100 ± 857 Mg/kg body weight respectively. CONCLUSIONS In accordance with expectations the mean serum iron concentration was found to be elevated in the viral hepatitis group but no significantly different from normal in the obstructive jaundice group. The results showed no evidence, however, of significantly depressed iron stores in any of the patients with viral hepatitis investigated, whatever their serum iron concentrations. On the contrary, the mean Fv values were elevated in all the groups investigated, the viral hepatitis group included. This elevation, while not unexpected in chronic liver disease and thalassaemia, is difficult to explain in viral hepatitis and obstructive jaundice. Despite the foregoing, the results do show some evidence that the serum iron concentration in viral hepatitis depends on the level of iron stores, in that the mean Fv value was higher in viral hepatitis patients with serum iron concentrations above 120 Mg/100 ml than in those with serum concen- trations below 120 txg/100 ml. 110 RESEARCH CONTRACT No. 1070 Summary of final report IAEA-R-1182-F TITLE Development of a radiochemical separation scheme for the determination of trace elements in biomedical samples by activation analysis (part of a co-ordinated research program on the medical applications of activation analysis). RESEARCH INSTITUTION United Kingdom Atomic Energy Authority, Aldermaston, Reading, Berks. , UK. PRINCIPAL SCIENTIFIC INVESTIGATOR F. Trowell. PERIOD OF CONTRACT 15 May 1972 - 14 May 1973. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT During the past several years a number of statistical associations, some of which may be causative in character, have become apparent between various aspects of trace element metabolism and cardiovascular diseases in man. These diseases, particularly atherosclerosis and ischaemic heart disease, are a major epidemic of modern times in the technologically advanced countries where they now account for more than 50% of all causes of death. A co-ordinated research program set up jointly by WHO and the IAEA in 1971 to study this problem has focussed attention on five trace elements considered to be of primary interest, Cd, Cr, Cu, Mo and Zn. Additional data are being sought under this program on the concentrations of these elements in a wide variety of biomedical materials, including autopsy samples of human tissues and human dietaries. The principal objective of the present study was to develop an automated solvent extraction apparatus and radiochemical separation scheme that could assist in the determination of these elements by thermal neutron activation analysis. By the use of automated methods, the number of samples that can be processed is increased and simultaneously the problem of quality control is simplified. EXPERIMENTAL METHODS The solvent extraction apparatus is a general purpose device that had already been developed by the principal investigators for various other applications, including the determination of trace elements in glass by 111 activation analysis. It permits two samples at a time to be subjected to a sequence of solvent extraction steps designed to produce a number of extracted fractions each containing one or more of the desired elements. The apparatus incorporates a programmer unit by means of which the sequence of solvent extraction steps, including the dispensing of reagents and the operation of a fraction collector, can all be manually programmed and recorded on magnetic tape. On playback of the tape the sequence of steps is exactly repeated. The radiochemical separation scheme developed for use with the apparatus requires the prior oxidation and dissolution of the samples following activation by thermal neutrons in a reactor. The samples are oxidized with concentrated H2S04/HN03, evaporated to dryness and fused with K2CO3/KNO3. The purpose of the fusion is to oxidize Cr and Mo to their highest valency states. The fusion mixture is then dissolved in H2S04 solution and introduced into the separator. Chromium and molyb- denum are extracted with 5% tri-n-octylamine in carbon tetrachloride, copper and cadmium are extracted with 0. 1% diethylammonium- diethyldithiocarbamate (DDDC) in carbon tetrachloride, and, after adjustment of the pH, zinc is extracted with 1% DDDC in carbon tetrachloride. RESULTS OBTAINED The radiochemical separation scheme was tested using synthetic mixtures of tracers in the presence of carriers, and yields of greater than 95% were obtained in each case. A limited number of experiments was also made in the presence of 1 g of wet heart tissue, mainly to establish the validity of the wet oxidation and oxidizing fusion reactions, and these also gave approximately quantitative recoveries. The apparatus has since been delivered to the IAEA Laboratory, Seibersdorf, for further evaluation under conditions of routine use. CONCLUSIONS An automated radiochemical separation method has been developed for the determination of Cd, Cr, Cu, Mo and Zn in biomedical materials by thermal neutron activation analysis. Yields of the radiochemical separation scheme are greater than 95% for all the elements of interest. Interfering radionuclides such as 24Na and 32P are not extracted. The method is suitable for routinely processing ~10 samples per day. PAPER PUBLISHED ON WORK DONE UNDER THE CONTRACT TROWELL, F., HERRINGTON, I., GOODE, G.C. , "Automated solvent extraction apparatus and radiochemical separation scheme for the determination of cadmium, chromium, copper, molybdenum and zinc in biological materials", Trace Elements in Cardiovascular Diseases (Proc. Res. Coord. Meeting Vienna, 1972), IAEA, Vienna (in preparation). 112 DOSIMETRY RESEARCH CONTRACT No. 837 Summary of final report IAEA-R-837-F TITLE Direct internal radiation dosimetry of radiopharmaceuticals by improved needle-type fluoroglass dosimeter. RESEARCH INSTITUTION Second Department of Medicine, University of Tokyo, Japan. PRINCIPAL SCIENTIFIC INVESTIGATOR M. Iio. PERIOD OF CONTRACT 1 December 1969 - 30 November 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT The need for internal radiation dosimetry devices is a very important but unfortunately insufficiently resolved problem in the radiation diagnostic, therapeutic and radiological health fields. The estimated dosages from internally applied radiation sources have usually been based on calculations and recommendations by the Medical Internal Radiation Dose Committee. Direct in vivo techniques for internal dosimetry have not been developed to a completely satisfactory state. The purpose of this project was to evaluate the possibility of direct internal radiation dosimetry of radiopharmaceuticals by an improved needle- type fluoroglass dosimeter. The scope of the research project was: (1) improvement of the existing rod-type fluoroglass dosimeter; (2) improvement of the fluorimeter system; and (3) in vivo study with 100-pi Ci131I aqueous solutions with rats and comparison with the calculated data. EXPERIMENTAL METHODS To improve the rod-type glass dosimeter, several modifications in the composition and 'systematic' research of the quality of glass were carried out. The newest glass to be developed is composed of 55 wt. % A1(P03)3, 30 wt. % NaP03, 15 wt. % Mg(P03)2 with the addition of 2. 5 wt. % AgP03. This is superior to the previously developed glasses in energy dependency, chemical durability and workability. 113 Several modifications and improvements of the fluorimeter system made it possible to measure low-level radiation exposure in the range of 3 mR, As light source a super-high pressure mercury lamp (100 W) with a high intensity point source and parabolic mirror was used. In this way 60 times more light could be focused on the glass rod than with previous instruments. Aphotomultipliertübe (PM55) was selected that has higher sensitivity to red light and negligible dark current. After these modifications the linearity and sensitivity of the system were investigated by using a calibrated ionization chamber and a 100-ß Ci131I aqueous solution in a 500-ml beaker. RESULTS OBTAINED The overall results can be summarized as follows: The rod-type glass dosimeter has been improved by decreasing the energy dependency and lowering the predose as compared with previously available products. It can be cut more easily and accurately to the size of 1 mm dia. x 6 mm. Modifications of the fluorimeter system have improved the linearity and sensitivity of the system. Comparison with other techniques has proved that this system is suitable for animal experiments. However, the results of experiments with rats showed a big discrepancy with the calculated data, which could be caused by differences in geometry and must be investigated further. CONCLUSIONS By combining the modification of the measuring instrument and the glass rods, the investigator has succeeded in measuring low-dose radiation in the range of 3 mR. This is about 300 times more sensitive than the previous rod- type dosimeters. The linearity of the system has been proved and the results of using glass rods and TLD were compared with the calculated values from MIRD. However, in vivo experiments revealed certain discrepancies with the calculated data, which may be caused by differences in geometry and need further investigation. PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACT YOKOTA, R.. MUTO, Y., "Recent improvement of glass dosimeter", 12th Int. Cong. Radiology, 1969. YOKOTA, R. etal., Recent improvement in fluoroglass dosimeter, Toschiba Rev. (27 Dec. 1970). YOKOTA, R., MUTO, Y., Silver activated phosphate dosimeter glasses with low energy dependence and higher sensitivity, Health Phys. 20 (1971) 662. YAMADA, H. etal., 1311 albumin microaggregates for liver-spleen scanning, Jap. J. Nucl. Med. 8 (1971) 80. IIO, M., et al., "Direct in vivo measurements of internal absorbed dose by radiopharmaceuticals using improved glass-rod dosimeter", 32nd AnnualMeeting Japanese Society of Radiology, 1973. YOKOTA, R., IMAGAWA, H., Radiophotoluminescent centres in silver-activated phosphate glass, J. Phys. Soc. Jap. 23 (1966) 1038. 114 HYDROLOGY RESEARCH CONTRACT No. 809 Summary of final report IAEA -R-809 -F TITLE Application of isotopic techniques in the hydrological study of the Aconcagua River Basin. RESEARCH INSTITUTION Corporacion de Fomento de la Producción, Departmento de Recursos Hidráulicos, Santiago, Chile. PRINCIPAL SCIENTIFIC INVESTIGATOR O. Castillo; later F. Alamos. PERIOD OF CONTRACT 1 November 1969 - 30 November 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT The study carried out within the scope of the research concerns the application of nuclear techniques to study the hydrology of the Aconcagua River Valley where the demand for water, both for domestic and agricultural use, is increasing rapidly. The study conducted includes: (1) discharge measurements at selected sections of the River Aconcagua and its tributaries by using 131I; (2) use of the point dilution technique to study the direction of groundwater flow in the phreatic alluvium aquifer of the valley; and (3) application of environmental isotope techniques to study the recharge mechanism and origin of recharge to the aquifers in the valley with particular emphasis on the possible contri- bution of the River Aconcagua to recharge the adjacent aquifer. EXPERIMENTAL METHODS AND RESULTS Twenty discharge measurements covering a range of 0. 3 to 50. 2 m3/s were performed at four selected river sections by using the instantaneous injection method and 131I as tracer. The results of these measurements enabled precise discharge rating curves to be developed and were compared with the results of measurements performed by using current meters. Determinations of the direction of groundwater flow of nine selected wells tapping the phreatic aquifer in the valley were made by injecting 131I into the wells and the results obtained confirmed the available piezometric data. 115 Samples collected from the River Aconcagua at six sections and from various wells tapping the aquifer adjacent to the river were analysed for their environmental isotopic composition (mainly 180, partly D and T). Inter- pretation of the environmental isotopic results permitted a study of the source of recharge to the aquifer and it was found that the River Aconcagua could be the most important source of recharge all along the river, CONCLUSIONS Within the range of discharge measurements performed in this study flow gauging using instantaneous injection of radioactive tracer (131I) yielded satisfactory results. A few modifications of the field equipment were suggested to improve the accuracy of the results. The use of radioactive tracers for the determination of the direction of groundwater flow by the point dilution method proved to be successful and the results obtained are in complete agreement with the piezometric knowledge of the aquifer system. Environmental isotopic analyses of the water samples collected from various sources in the Aconcagua Valley enable interpretations and evaluations to be made regarding the mechanism and source of recharge to the phreatic aquifer in the valley. It was found that a significant contribution occurs from the River Aconcagua to the adjacent phreatic aquifers of the valley. 116 RESEARCH CONTRACT No. 1011 Summary of final report IAEA-R-812-F TITLE Determination of 180/ 160 ratio in precipitation (rain and snow). RESEARCH INSTITUTION Central Research Institute for Physics, Laboratory of Mass-Spectrometry, Budapest, Hungary. PRICIPAL SCIENTIFIC INVESTIGATOR I. Opauszky. PERIOD OF CONTRACT 1 November 1969 - 31 August 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT The isotopes of the same element do not behave identically in physico- chemical processes. Condensation and evaporation processes cause isotopic fractionations in waters. These processes, which are essentially governed by temperature variations, trace isotopically natural waters. It is, there- fore, possible to have information on the meteorological 1 history' of precipi- tation from its isotopic composition. It was planned to measure the lsO/ 160 ratio on precipitation samples collected over three years at different times and stations near the Central Institute for Physics, located 5 km west of Budapest. For the measurement, a M 1-1305 mass-spectrometer was used. The specific work program was: (a) equipment modification to deter- mine, with higher accuracy, the stable isotope ratios; ( b) measurement of stable isotope contents of precipitation samples; (c) correlation of results with those obtained from nearby geographic provinces; (d) interpretation of results on the basis of hydrometeorological theories. EXPERIMENTAL METHODS During the research contract period 51 precipitation samples were collected and analysed for their 180/160 content. Samples were taken routine- ly twice a month over a period of two years. In addition, precipitation under particular meteorological conditions was sampled and measured. The water was equilibrated withtank C02 and the oxygen isotopic composition was measured on a modified double-collector mass-spectrometer by the compensation method. For the measurements, ' home standards' were used, calibrated in separate runs versus the Vienna-SMOW supplied by the IAEA. A significant improvement was obtained in the registration of the ' error signal1 by using the CARY-401 electrometers supplied by the IAEA. 117 RESULTS OBTAINED The history of the atmospheric moisture from which the precipitation originated has been reconstructed. The temperature variations were shown to correlate with the precipitation 180/ 160 ratios. A single rain shower showed that samples collected early, middle and at the end of the shower gave quite different 180/ 160 contents, which can provide information on the physical processes of precipitation. In three cases air moisture samples were taken and analysed; in each case the 6lsO content reflected the arrival of wet air masses by the increase in ó 180 values approximately simultaneous with the decrease of the atmos- pheric pressure. 18 The mean values observed in ô O%0 weighed for amount of precipitation were: 1970 1971 Winter (69/70, 70/71 ) -13.9 -15,2 Spring -8.9 -5,6 Summer -6.6 -1.4 Autumn -13.0 -10,1 Annual mean -9.8 -9.1 The accuracy of measurements was ±0. S^ooó 180. CONCLUSIONS In general, the results obtained for precipitation samples showed the well-known correlation of 180/160 variations with air temperature and origin of air mass. On the other hand, some results suggest that, in spite of the apparently significant disturbances in the air masses movements caused by the moun- tains around the site of sampling, the 6lsO content of rain is governed mainly by the air masses coming from the Atlantic. 118 RESEARCH CONTRACT No. 1011 Summary of final report IAEA-R-847-F TITLE Investigation of the connection of the subsoil water with underground water in the Nile Delta (Egypt) using isotopes. RESEARCH INSTITUTION Middle Eastern Regional Radioisotope Centre for the Arab Countries, Cairo, Arab Republic of Egypt. PRINCIPAL SCIENTIFIC INVESTIGATOR I. B. Hazzaa. PERIOD OF CONTRACT 1 December 1969 - 30 November 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT Hydrological investigations in the Nile Delta have shown that both the water level of the cultivated layer and the underground water level fluctuates throughout the year. The present studies were performed to investigate the vertical drainage from the cultivated layer by pumping from underground water using nuclear techniques. EXPERIMENTAL METHODS The main locality of the investigation was Shebin El-Kom in the middle of the Nile Delta region. Another locality, Damanhour El-Wahsh in the same region, was chosen for confirmation. Both localities are provided with pumping stations. Deep and shallow wells were sunk. Some of the shallow wells were provided with chart recorders to record the subsoil water levels. Soil samples and water samples were collected during drilling deep wells, Soil samples obtained from different depths in the two localities men- tioned above were closely examined, emphasis being given to: (a) lithology of the succession; (b) mineralogy of different horizons; and (c) mechanical analyses. The subsoil and groundwater samples were analysed to determine the major constituents. The water levels in each of the shallow wells were recorded during the periods of non-pumping and pumping. The following investigations were performed: (a) The tritium content of each of the water samples collected during drilling deep wells was determined. This was performed using enrichment 119 by electrolysis equipment and the Tri-Carb Packard liquid scintillation spectrometer in the Centre. (b) Using the moisture measuring equipment (neutron source) the moisture content of strata at different depths was determined before and after pumping in the different wells. (c) The bulk density was determined for the strata of the wells in the Shebin El-Kom locality using the density measuring equipment (gamma source). (d) A few millicuries of 131I and 32P were injected in a shallow well in the Shebin El-Kom area. The activity in 12 surrounding aluminium tubes had been continously assayed during the periods of non-pumping and pumping. The velocity and the direction of the movement of the subsoil water were determined. RESULTS OBTAINED The detailed results of the soil and water samples analyses are listed in tables in the reports. The subsoil water in both areas is characterized by low TDS at the sur- face of the same order of magnitude as that of the Nile water. The TDS values increase gradually with depth. The subsoil water levels in the various shallow wells were found to lower gradually with pumping. After long periods of pumping they reached a steady level. The infiltration velocity of subsoil water to underground water in the Shebin El-Kom area was found to be about 1. 7 m/yr and in the Damanhour El-Wahsh area about 2.7 m/yr. The moisture content of the different strata was found to decrease with pumping. The bulk density was found to decrease with the decrease in the moisture content of the strata. The horizontal velocity of the subsoil water was found to vary from 0. 3 m/yr before pump- ing to 0. 33 m/yr during pumping and the direction of flow was found to deviate with about 30° towards the pump. CONCLUSIONS Conventional hydrological observations together with the results obtained using nuclear techniques indicate that there is a connection between the subsoil water and the underground water in the Nile Delta region. PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACT HAZZAA, I. B. , SOLEIT, M.L., SHATA, A.A., MOSTAFA, H.M., SWAILEM, F.M., Tritium contents of the Nile Delta zones indicating the movement of the subsoil water, Isot. Radiat. Res. (1972) 12. HAZZAA, I. B., GIRGIS, R. K.. Investigation of the infiltration of the subsoil water to the underground water in the Nile Delta using nuclear techniques, submitted for publication in Isot. Radiat. Res. 120 PROTECTION OF MAN AND HIS ENVIRONMENT RADIATION BIOLOGY RADIOLOGICAL SAFETY RADIATION BIOLOGY RESEARCH AGREEMENT No. 503 AND RESEARCH CONTRACT No. 873 Summary of final report IAEA-R-873-F TITLE Irradiation induced changes in red blood cell metabolism and membrane structure. RESEARCH INSTITUTION National Institute of the National Blood Service, Budapest, Hungary. PRINCIPAL SCIENTIFIC INVESTIGATOR S.R. Hollán. PERIOD OF CONTRACT 1 April 1968 - 31 December 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT Ionizing radiation influences the metabolism and permeability of erythrocytes significantly. Investigations carried out so far deal in general with membrane damage, permeability change and intracellular alterations separately. A comprehensive study was performed here from various aspects to elucidate the inter-relationships of these complex problems using mature or immature anucleated or nucleated erythrocytes. The characteristics of membrane surface of erythrocyte, the state of SH-groups, the membrane permeability as well as the intracellular biochemical changes were investigated. Emphasis was placed on the radiation-induced changes in the transport of iron, a radiosensitizing agent, and on the mechanisms of its utilization. EXPERIMENTAL METHODS Mature and foetal human erythrocytes, and chicken and rabbit erythro- cytes were used. Irradiation was carried out mainly with X-rays in the dose range 1000 to 25 000 R. Biochemical indices examined are as follows: the number of surface SH-groups, cholesterol, fatty acid ester, phospholipid, fatty acid composition; acetylcholine esterase, ATPase; glutathione reductase, hexokinase, and G-6-P dehydrogenase; permeability for alkali cations, heavy metals, glycerol, thiourea and glucose; reduced glutathione, ATP; glycolysis rate; iron binding to and detachment from transferrin (complex); haemoglobin synthesis. Radioisotopic techniques were used in the study of iron behaviour. 123 RESULTS OBTAINED In mature human erythrocytes permeability increased for monovalent cations, mercuric ions and compounds, glycerol and thiourea. G-6-P dehydrogenase and hexokinase were activated with the latter leading to the decreased ATP level in the cell. GSH reductase showed a decreased activity. Iron exhibited a radiosensitizing effect with regard to membrane permeability for alkali cations and heavy metals. No changes were observed in chicken erythrocyte membrane both in permeability and in binding capacity for iron from crystalloid medium. Iron uptake from transferrin-iron complex, however, decreased by 25-35% after exposure to 25 000 R X-rays, by which a 30-60% decrease in Hb synthesis was also noted. In foetal human erythrocytes uptake of free iron or iron from labile transferrin-iron complex increased by 150-200% after X-irradiation with 25 000 R. Treatment with NaCN (5mM) or fluoroacetate (16mM) inhibited the iron uptake by immature cells from labile transferrin-iron complex, and also abolished the enhanced iron uptake to be observed after X-irradiation with 25 000 R or treatment with inosine (lOmM) and adenine (ImM). It was shown in rabbit erythrocytes that irradiation leads to irreversible injuries in mitochondria and a concommitant disturbance in intracellular iron transport between cell membrane and mitochondria. CONCLUSIONS X-ray irradiation of erythrocytes induces changes in biochemical constituents of its membrane and intracellular structure, and hence alter- ations in membrane function and cellular metabolism. Membrane perme- ability increases, hexokinase and G-6-P dehydrogenase are activated and ATP content decreases after irradiation. The radiation effect on membrane binding is different between human and chicken erythrocytes; an increased binding observed in the former does not occur in the latter. Foetal human erythrocytes provide a suitable material for the study of radiation effect on iron uptake from labile transferrin-iron complex. This process is susceptible to irradiation or action of metabolic inhibitors. Irradiation of rabbit erythrocytes results in irreversible mitochondrial injuries and concommitant disturbances in intracellular iron transport. PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACT ARKY, I., SZÀSZ, I., GARDOS, G., SZELENYI, J.G., BREUER, J.H., VARTERESZ, V., HOLLÁN, S.R., Biochemical changes in blood induced by in vitro X-irradiation, Haematologia £(1969) 51. ARKY, I., Sensitive method for the in vitro detection of very small X-ray doses, Haematologia £(1971) 97. 124 RESEARCH CONTRACT No. 1011 Summary of final report IAEA-R-722-F TITLE The succession of plankton communities and their primary produc- tivity in artificial water reservoirs in Nigeria. RESEARCH INSTITUTION Department of Biological Sciences, University of Ife, Ile-Ife, Nigeria. PRINCIPAL SCIENTIFIC INVESTIGATOR A. M.A. Imevbore. PERIOD OF CONTRACT 1 January 1969 - 31 December 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT The major ingredient of diet in Nigeria is gari from cassava, which is rich in starch content and very low in protein. Consequently, in the Nigerian diet fish is much favoured and serves as an essential ingredient to prevent protein malnutrition. However, the country's fish production from all available local resources is grossly inadequate and meets hardly one-fifth of the total estimated need. For several years the federal and state governmental authorities have taken various measures to develop and improve the marine and freshwater fishery resources of the country. One such step involves the development of artificial lakes, ponds and water reservoirs (e.g. Kainji Lake) to undertake fishery cultures. The present research deals with the use of radioisotope tracer techniques to investigate the primary productivity and the ecological succession of phyto- and Zooplanktons and other plant communities relevant to the growth of the fish populations of Nigerian lakes. The project's objectives also included the identification of the factors involved in the eutrophication of tropical lakes. The studies were aimed at the increased provision of fish protein for dietary consumption in Nigeria. EXPERIMENTAL METHODS The standard hydrobiological methods utilizing 14C-labelled bicarbonate have been followed in the studies on in situ measurements of primary pro- ductivity of the planktonic plant communities in the experimental ponds. Parallel records of the meteorological conditions (viz. illumination, temperature, humidity and plankton density) throughout the year have been kept and the estimated rates of biomass productivity have been correlated 14 14 with them. Through the uptake and fixationof C fromNaH C03 added as carbon source and the radioactivity counts of the samples taken from various depths 125 of the water body, the biomass productivity has been calculated. Charac- teristics of the phosphate uptake and exchange processes of the natural phytoplankton populations were studied by the standard methods for trans- port systems using 32P-labelled compounds. The measurement of nitrogen fixation (using 15N label) was attempted but was handicapped due to the lack of facilities including a spectrophotometer for the reading of the samples. RESULTS OBTAINED Based upon the data on 14C-fixation by the planktonic flora and fauna and 15 sets of measurements conducted during an 18 month period, the average rate of primary productivity of the experimental fish pond near the surface is estimated to be 1 - 2 g C • m~2 • d"1. The experimental pond is 107 metres wide and about 350 metres long with an average depth of about 2-3 metres during most of the year. In accordance with the average rate of biomass productivity, the daily basal rate of primary production in the pond is at the lowest about 30- 60 kg carbon and the annual value is in the range of 20 - 30 tons. The in situ measurements were evidently strongly influenced by the daily illumination and the productivity can be rather low during the cloudy days of the long wet season. The laboratory measurements of the potential productivity showed a gradual increase in the quantity of phytoplankton when the first rains started to arrive (January-April). This increase is supposed to be due to improved nutrition of plankton caused by the leaching of nutrients from the soil of the watershed. The observations of rather low phosphate and inorganic nitrogen contents of the water samples initiated the studies of the P and N nutrition characteristics of the phytoplankton. Two main processes for incorporation of 32P-labelled phosphate by the phytoplankton are indicated. At low con- centration levels the uptake is probably dominated by active transport influenced by the intensity of illumination. Further support for this hypothesis comes from the susceptibility of this process to inhibition by cyanide, a respiratory inhibitor. At higher levels of phosphate content (above 0. ImM per litre) an alternative passive process of uptake seems to dominate as the incorporation of 32P becomes mostly insensitive to the respiratory inhibitors. The 32P uptake at low concentration range may provide a simpler assay method for the activity of the plankton populations. CONCLUSIONS The investigations illustrate that much useful information can be obtained by simple radioisotope tracer methods for the effective manage- ment of tropical fish ponds. Furthermore, one of the important factors of the low fish production by the West African fish ponds seems to be their low primary productivity. It is very probable that the low primary produc- tivity can be traced back to the low P and N content of these fresh waters, and the productivity of these ponds could thus be increased by carefully regulated N and P fertilization. 126 PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACT IMEVBORE, A.M. A., MESZES, G., BÔSZÔRMÉNYI, Z., "The primary productivity of a fish-pond at Ile-Ife, Nigeria," Productivity Problems of Freshwaters, Warsaw-Cracow (1972) ,715-23. IMEVBORE, A.M.A., BÔSZÔRMÉNYI, Z., Ion transport studies on phytoplankton of a fish pond at Ile-Ife, Arch. Hydrobiol. 69 (1971) 200-9. BOSZ.ORMÉNYI, Z., IMEVBORE, A.M. A., "Phosphate absorption as an index of phytoplankton activity: the case at Lake Kainji, " The Ecology of Lake Kainji, Ife University Press (in press). 127 RESEARCH AGREEMENT No. 795 Summary of final report IAEA-R-795-F TITLE Effect of irradiation on the microecosystem of sewage (part of a co- ordinated program of research on the study and improvement of biosphere resources). RESEARCH INSTITUTION Department of Biochemistry, Faculty of Science, M.S. University of Baroda, India. PRINCIPAL SCIENTIFIC INVESTIGATOR C.V. Ramakrishnan. PERIOD OF AGREEMENT 1 April 1970 - 31 May 1973. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT In the treatment of domestic and municipal sewage, the oxidation pond step normally requires as long as 28 days. In the course of this treatment the various organic components of the sewage are oxidatively decomposed by the sewage microflora. The effluent from the oxidation pond is reasonably clear and may be used for irrigation in agriculture, provided it is free from pathogens and parasitic organisms. Although chlorination is a relatively cheap method of treatment, it does not destroy worms and spores efficiently. Moreover, an excess of free residual chlorine seems to inhibit the growth of sewage algae, which play essential roles in the purification of sewage in oxidation pond. A significant improvement in the sewage treatment practice should involve (a) the development of a high-rate oxidation pond, which should cut down the total retention period from 2 8 days to only about one week; (b) the development of methods for the effective destruction of pathogenic microorganisms and parasitic organisms in the sewage; and (c) the increased efficiency for biodégradation of organic components by the microorganisms in the oxidation pond. Attempts have been made to use gamma irradiation from 60Co sources to meet these objectives. The information accumulated from research carried out under this project has formed the basis for new tech- niques, including the use of radiation, which could facilitate the sewage management and safe reutilization of sewage waters for irrigation purposes. EXPERIMENTAL METHODS The research involved a wide range of investigations including the aspects of microbiology, analytical biochemistry, isolation and identification 128 of the pathogenic organisms in common domestic sewage, as well as radiation microbiology and ecology of sewage microflora. The oxidation pond for sewage treatment was simulated in the laboratory by setting up 5-litre flasks, each containing 1. 5 litres of fresh raw settled sewage. They were sterilized in an autoclave and plugged with sterilized non- absorbent cotton. Cultures of algae (Chlorella) and bacteria representatives of sewage microflora were inoculated in the sterile sewage with appropriate precaution, illumination and temperature controls. Samples were drawn at intervals and the qualitative and quantitative analyses for the types and relative numerical frequencies of the inoculated species of microorganisms were carried out. Evaluation of the effectiveness of algal-bacterial symbi- osis in high-rate oxidation ponds involved the determinations of biological and chemical oxygen demands. In addition the rates of removal of coliform bacteria and the biostimulatory nutrients in the treated sewage were also investigated as the function of different detention periods in the oxidation ponds. Biochemical tests included the hydrolysis of starch, protein and tributyrin, among other organic substances. Radiation microbiology studies involved the inoculation of sterilized sewage samples with different species of pathogenic bacteria and parasitic worms followed by their treatment with 60Co gamma radiation (doses ranging from 0.1-0. 01 Mrad) for estimation of radiation dose-survival relationships. Parallel studies were conducted with these organisms following their treatment with either chlorine alone or chlorine in combination with gamma rays. From the bacteria sampled periodically from sewage and those subjected to irradiation with 60Co gamma rays, attempts were made to isolate new mutants showing improved capacity for breakdown of cellulose, fat and proteins. RESULTS OBTAINED The results have shown that the normal duration of domestic sewage purification process in the oxidation ponds can be significantly reduced. It is possible to decrease the retention time from 2 8 days to 6 days in the oxidation pond by inoculating the raw sewage with massive doses of algae, such as Chlorella vulgaris, Scenedesmus obliqus and Oscillatoria sp. Gamma irradiation of sewage with a dose of 0. 1 Mrad facilitates the settling of suspended organic solids without affecting the algae adversely. Studies on the sensitivity of the pathogenic parasites to gamma irradi- ation from 60Co sources showed that, despite the variability between the species studied, the most radioresistant ones were killed at a dose of 0. 1 Mrad. A dose of 0. 01 - 0. 05 Mrad gamma radiation was found to eliminate about 99% of the pathogenic organisms investigated. At the level of 0. 05 Mrad the adverse biological effects on the algae were reported to be negligible. Furthermore, in the laboratory tests, which have formed the basis of these data, the sterile sewage samples were inoculated with titres of the pathogens much higher than those encountered in the sewage treatment plants. From this it was concluded that a radiation dose much lower than 0. 05 Mrad, when given in combination with chlorine, should be able to, disinfect sewage waters to a level safe for irrigation purposes since it should be able to control effectively all the undesirable pathogenic organisms in sewage water and should not involve too high a cost factor. 129 The project's results also included the isolation of several mutants of the bacterial species Bacillus subtilis from the gamma-irradiated sewage, which performed the rapid breakdown of starch and gelatin. Further mutagenic treatment of those mutants with 5-bromouracil (5-BU) gave two additional mutants, one showing high amylase activity and the other "high protease activity. These mutants also showed the capability for using cellulose as the sole carbon source. The two mutants selected after 5-BU treatment, when inoculated on sewage along with appropriate algae, were able to decompose the organic contents of sewage very effi- ciently in six days without much of the sludge left behind. The clear effluent had the desirable properties for safe use in irrigation for agriculture. CONCLUSIONS While the use of gamma irradiation alone for sewage processing seems to prove uneconomic, other alternate possibilities from combining radiation with chorination as well as through the improvement of microbial bio- degradation by selecting appropriate mutants could provide additional methods of choice that might render the process economically feasible and at the same time effective. The data reported so far have been obtained from small laboratory studies and hence those might not be suitable for direct extrapolation to the field conditions. For this pilot-plant studies of appropriate design and dimensions need to be undertaken. However, despite the many aspects of the processes still to be clarified, the inves- tigations under the project should be encouraged. Those simultaneously deal with the multifarious welfare problems of public health and food as well as a rational utilization of the biosphere resources of human environment. PAPERS PUBLISHED ON WORK DONE UNDER THE AGREEMENT RAMAKRISHNAN, C.V., Possible use of gamma irradiation in waste water treatment, J. Sei. Ind. Res. 30 5 (1971) 228-34. GANAPATI, S.V., Biochemical Studies on Algal-bacterial Symbiosis in High Rate Oxidation Ponds with Varying Detention Periods and Algae, First Ann. Rep., Biochemistry Department, Baroda University (1971). TAMAN, G. A., DAVE, P.J., Isolation of bacterial mutants from raw sewage with amylase and protease activities, J. Sei. Ind. Res. (in press). RAMAKRISHNAN, C.V., TAMAN, G. A., Effect of gamma radiation on the protease and amylase producing bacteria involved in sewage purification, J. Sei. Ind. Res. (in press). 130 RESEARCH CONTRACT No. 1011 Summary of final report IAEA-R-833-F TITLE Reduction in radiosensitivity of mammalian cells by chemical means. RESEARCH INSTITUTION Radiobiology Department, Cekmece Nuclear Research and Training Center, Istanbul, Turkey. PRINCIPAL SCIENTIFIC INVESTIGATOR H. Hughes; later A. ¡pengün. PERIOD OF CONTRACT 1 December 1969 - 31 December 1973. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT Much evidence exists that chemical radioprotectors can protect organisms against the lethal and harmful effects of ionizing radiations, when administered prior to or during irradiation. It is also known that sulphydryl radioprotectors decrease DNA synthesis, inhibit mitosis and affect the metabolism of cells treated. However, the exact mechanism of chemical radioprotection is not yet fully understood. The purpose of these investigations was to study the effects of AET (S, ß-aminoethylisothiouronium. Br. HBr) on the survival of rat embryonic cells in tissue culture exposed to different doses of gamma radiation, and on the DNA, RNA and protein syntheses in both irradiated and unirradiated cells. EXPERIMENTAL METHODS Survival of rat embryonic cells incubated for 3 0 minutes in a tissue culture medium (TC-199) containing 10% calf serum and various concen- trations of AET (ranging from 16 to 45mM) was studied to determine the toxicity of this substance. The metabolic effects of AET in the highest non-toxic concentration were studied in the same system by comparing the nucleic acid and protein synthesizing ability of pretreated cells with that of untreated ones. Following incubation of cells in AET, tritiatedprecursors of DNA (thymidine), RNA (uridine) and proteins (glycine) were added to the culture medium for another 30 minutes, then autoradiograms were prepared with the use of stripping film technique. The rate of DNA, RNA and protein synthesis was established from the number of grains over the nucleus, whole cell area and nucleolus, respectively, and compared with that of the untreated cells. The radioprotective activity of AET was examined by exposing cells to different doses of gamma radiation from a 60Co source in the presence 131 and absence of the compound. The cell survival was determined by counting the number of viable cells in well-defined areas of Petri dishes prior to and 24 hours after irradiation. The effect of AET on the alterations induced in DNA, RNA and protein synthesis by radiation was also determined. RESULTS OBTAINED Approximately 40mM of AET was found to be its mean lethal concen- tration for rat embryonic cells incubated for a period of 30 minutes, and 20mM of the compound proved to be the highest non-toxic concentration. Incubation of rat embryonic cells for 3 0 minutes in a culture medium containing 30mM AET resulted in a significant reduction in the synthesis of nucleic acids and proteins. The extent of reduction in DNA, RNA and protein synthesis was 13, 27 and 39% when the cells were examined immedi- ately after the removal of AET, and 32, 37 and 31% 24 hours after the incubation. Exposure of cells to doses of gamma radiation of 390, 580, 870 and 1060 R decreased the survival of cells to 87. 0; 62.2; 57. 7 and 50. 0%, respectively. At the same time of observation the number of unirradiated, control cells increased to about 160% of the initial value. The presence of AET in the culture medium during irradiation abolished completely the decrease in survival of cells irradiated with doses from 390 to 870 R. The radiation-induced depression in DNA synthesizing activity of cells was also diminished from 52. 8 to 27. 4% in the presence of AET. On the other hand, the compound did not influence significantly the radiation- induced alterations of RNA synthesis (38.2% versus 36.9%), and even aggravated the disturbance in protein synthesis, reducing it by 49.6% instead of 35. 8% caused by radiation in the absence of AET. CONCLUSIONS The experimental results presented confirm the literature data on the radioprotective activity of AET. This radiation protection has been demonstrated in the increase of survival of rat embryonic cells exposed to lethal doses of ionizing radiation in culture. Concerning the mechanism of action, it seems important that a corre- lation exists between the radioprotective and metabolic effects of the compound, the latter manifesting itself in depression of DNA, RNA and protein syntheses of pretreated cells. It is suggested that slowing down of the metabolic activity and mitotic cycle in cells leads to a state of their enhanced radioresistance or repair capability. PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACT UÇER, E., BÖLÜKBAJI, E., Determination of the toxic effect of AET on rat embryonic cells, Revue Fac. Sei. Univ. Istanbul, Serie B 37_(1972) 145-48. SÇNGUN, A., BÖLÖKBAJI, E., UÇER, E., ANIL, D., Radioprotective and metabolic effects of AET on rat embryonic cells in tissue culture, Cekmece Nuclear Research and Training Center, Report Series (to be published). 132 RESEARCH CONTRACT No. 1011 Summary of final report IAEA-R-846-F TITLE Characterization of useful mutations in fungi induced by radiation and radioisotopes and the study of their biosynthetic products (part of a co- ordinated program of research on radiation microbiology). RESEARCH INSTITUTION Bose Institute, Department of Microbiology, Calcutta, India. PRINCIPAL SCIENTIFIC INVESTIGATOR K. Chaudhuri. PERIOD OF CONTRACT 1 January 1970 - 31 December 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT Citric acid is among the most widely utilized organic acids in the food, pharmaceutical, chemical and leather-processing industries and represents one of the metabolic intermediates of the tricarboxylic acid cycle of the respiratory pathways. Some selected mutant strains of the mould Aspergillus niger are able to produce citric acid in large quantities. This feature has been utilized in the large-scale industrial production of this organic acid in fermenters. Improvement of microbial strains for their ability to give greater yields of citric acid is thus one of the major factors for the large-scale economic production of this chemical. Molecular and biochemical genetic research has established the genetic basis for citric acid production including the role(s) of cellular regulatory processes. These findings have also been helpful in the improvement of strains by inducing new mutations by radiation and chemical mutagens followed by appropriate selection methods. The traits determining the larger yields of citric acid in the different selected mutants could be further combined through planned breeding and genetic recombination. Successful development of such mutant strains and the relevant genetic and biochemical information on the regulation of the biosynthetic pathways could provide a source of fermentative production of this essential organic acid in the developing countries. In addition, this could open up an avenue for the utilization of the locally available agricultural by-products as the sole inexpensive carbon source for citric acid production. EXPERIMENTAL METHODS More than 250 strains of Aspergillus niger and other species of Asper- gillus were collected from the different soils of India and subjected to 133 preliminary screening for total acid production by plating in agar media containing colour indicator. The index of acid unitage was determined by the ratio of the diameter of the clear acid zone to the diameter of the mycelial colony. Fifteen strains were selected on the basis of high total acid pro- duction criteria. These strains were further subjected to mutagenic treat- ments with X-rays and ultra-violet irradiation. Conidial suspensions at 107 spores per ml were prepared with sterile distilled water from cultures in sporulating media. Various doses of X-irradiation ranging from 5 to 40 kR were applied to conidial suspensions under continuous stirring at 28°C. Ultra-violet irradiation doses were given by varying the exposure time from 3 to 30 minutes at 25°C. After the necessary dilution the irradiated spores were plated out in complete medium and the survival percentage as the function of dose was determined. The high acid yielding variants were further tested for citric acid production by culturing them on liquid media in 250 ml Erlenmeyer flasks. The citric acid content was determined by adding 1.3 ml of pyridine and 5.7 ml of acetic anhydride to 1 ml of culture filtrate and incubating in a water bath at 32°C for 30 minutes. Upon this treatment the citric acid solution turns yellow, the intensity of which was studied in a Klett Sommerson colorimeter at 420 nm. The Klett readings calibrated from the standard curve prepared from known quantities of citric acid gave the quantitative estimation of citric acid in the culture filtrate. Attempts were made to grow the promising strains on media containing molasses as the sole carbon source. Improved citric acid producer strains were crossed for the induction of nuclear recombination as a means of production increase. Chromatographic sepa- ration of the various organic acids in the culture filtrates from the liquid culture of various high and low citric acid yielding mutants were performed to characterize their metabolic patterns and the possible biochemical genetic explanations of their high or low citric acid production capacities. RESULTS OBTAINED Aspergillus niger mutants showing increased yields of citric acid in the culture filtrates were selected following both X-rays (35 and 40 kR) and u.v. irradiation (24 min). In both the mutagen-treated populations the selected mutants showed increases in citric acid yields as high as 100% or more as compared with the parental strains occurring naturally in Indian soils. A mutant strain of A. niger 6N3 derived from a 35-kR X-ray treated population gave as much as 53 g of citric acid per litre of culture filtrate and is considered as most commendable for further investiga- tion with regard to production increase through culture medium control and/or mutation-selection techniques. Two mutant strains isolated from u.v.-treated populations gave citric acid yields of about 50 g/litre of culture filtrate. In the current series of experiments 35 kR of X-rays and 24 minutes of u.v. proved to be most effective doses in producing A_. niger mutants with improved yield of citric acid. The citric acid production by some of the improved induced mutants was followed up to eight subculturing generations. None of these strains were found to be completely stable with regard to their quantitative yields of citric acid. The citric acid production curves in the successive genera- tions fluctuated, indicating possible segregation of the mutagen-induced 134 gross chromosomal aberrations. However, a comparison showed that mutants selected from X-irradiated populations had a more stable yield than their u. v.-irradiated counterparts. A detailed study was undertaken on the quantitative estimation of the yields of citric acid by the radiation- induced improved mutants in relation to their mycelial growth in culture and total acid production. Media promoting prolonged mycelial growth provide reduced quantities of citric acid in the culture filtrates. The selected citric acid producing mutants were cultivated in media in which molasses served as the sole carbon source. The metallic elements Zn and Fe present in molasses promoted citric acid fermentation. Molasses, however, showed deficiency for Mn and Cu, addition of which promoted the yield. Zn, Fe and some other elements when present in excess inhibit citric acid yields and their partial removal in the course of the purification process for molasses enhanced the yields of citric acid by the selected mutants. Nuclear recombination experiments using the selected mutants in various combinations gave rise to strains with a slight increase in yield of citric acid over their parental levels, which could possibly serve as a means for strain improvement through parasexual recombination. Chromatographic analysis of the citric acid producing and non-producing mutants provided some clue to their organic acid metabolic patterns. Non-citric acid pro- ducers were generally found to produce an excess of maleic, fumerie and succinic acids in addition to oxalic acid. The non-accumulation of citric acid in those strains may be due to slow rates of conversion of oxalic to citric acid. This may also be due to genetic and biochemical blocks in the biosynthetic pathway beyond the o-oxoglutaric acid step. The higher citric acid yielders were found to produce only oxalic acid in large quantities. CONCLUSIONS The information accumulated on the biosynthesis of citric acid by the radiation-induced mutants of Aspergillus niger is expected to prove valuable for microbial fermentation research in general. The results are indicative of the usefulness of radiation-induced mutations for the improvement of microbial fermentation practices. Besides, the induced mutants representing genetic blocks at specific sites of the biosynthetic pathways provide a most essential clue to the cellular regulation of the process concerned. These in turn help towards the further development of improved high-yielding strains. Genetic recombination between the improved strains through planned breeding programs holds promise and merits further exploration. PAPER PUBLISHED ON WORK DONE UNDER THE CONTRACT ABRAHAM, T.K., CHAUDHURI, K.L., "Improvement of citric acid yield of Aspergillus niger with UV and X-radiation", Proc. 60th Indian Science Congress, 1973 (in press). 135 RESEARCH CONTRACT No. 1011 Summary of final report IAEA-R-862-F TITLE Inactivation or attenuation of protozoa by ionizing radiation oriented toward the preparation of vaccines. RESEARCH INSTITUTION Institute of Cancer, Catholic University of Louvain, Belgium. PRINCIPAL SCIENTIFIC INVESTIGATOR A. Dunjic. PERIOD OF CONTRACT 1 January 1970 - 31 December 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT As compared with other physical and chemical agents, ionizing radiation can also inactivate protozoa and thus reduce their infectivity and virulence. The differential effects of ionizing radiation on proliferative capacity and antigenicity were considered in protozoan infections, in respect of which no success has so far been achieved in effectively immunizing persons exposed to the lethal action of these etiological agents. The work related to (a) inactivation of protozoan in culture by irradia- tion and, in one experiment, by a radioimimetic agent; (b) studies on the infectivity and virulence of irradiated trypanosomes in mice; (c) immuni- zation of laboratory animals; and (d) morphological and physiological changes in irradiated protozoa. EXPERIMENTAL METHODS The survival and growth of Trypanosoma cruzi (Tehuantepec) and Crithidia luciliae were studied in culture after irradiation with X-rays (250 kV) and gamma rays (137Cs) or treatment with actinomycin D. The infectivity and virulence of irradiated T. cruzi (Tehuantepec and Telahuen) were evaluated in mice as a function of radiation dose, time elapsed after irradiation and number of parasites on the basis of the following criteria; mortality, parasitaemia, organ culture, organ smears, histological sections and serology methods (Ouchterlony's immuno-diffusion and Ross's microagglutination). Irradiation or thymectomy and their conjugate effects were made the subject of experimental observations concerning the infectivity of the protozoa in rats. 136 Immunization experiments were carried out in mice, guinea-pigs and hamsters. Vaccinations with T. cruzi (Tehuantepec) and T. gambiense (Eliane) inactivated by irradiation (100 and 150 kR) were performed 1-4 times. Challenge infection with T_. cruzi (Tehuantepec and Telahuen) and T. gambiense was carried out after periods of 40 to 460 days. The morphology of irradiated T_. cruzi, C_. luciliae and T. brucei as well as the combined effects of irradiation and pharmacological agents (acriflavine and ethidium bromide) were studied with electron microscopy. RESULTS OBTAINED The growth curves for T. cruzi irradiated with gamma rays confirm the observations of Emmet (1950) and the results of Martinez-Silva and co-workers (1969), according to whom inactivation in culture requires doses higher than 50 000 R. The survival curve for C_. luciliae as a function of gamma-radiation dose is of the exponential type and has the following parameters (where N = extrapolation number corresponding to the inter- section of the exponential part of the survival curve with the ordinate for zero dose; D0 = the average lethal dose which, in the exponential part of the curve, reduces the surviving fraction of cells to 0. 37; and D^ = interaction of the exponential part with the abscisse for 100%^survival): N = 0.98 (0. 83 - 1. 13); D0 = 42 968 (33454- 60068) R; and Dq = 1507 R. The survival curve for C. luciliae treated with actinomycin D is sigmoid in shape. The parameters of the exponential part of the curve are evaluated as follows: N = 2. 61 (0. 82 - 8. 28); D„. = 0. 25 (0. 164 - 0. 528) Mg/ml; and Dq- = 0. 24 /ug/ml. Similar doses of actinomycin D also inactivate the proliferation of T. cruzi in culture. The results on the infectivity and virulence of irradiated T. cruzi inoculated into mice indicate that up to 50 000 R the doses used are inadequate for effective inactivation of the trypanosomes. Taking into account the number of trypanosomes usually inoculated in the immunization experiments, doses of 100 000 and 150 000 R had to be applied. The effective minimum amount of T. cruzi Telahuen injected subcutane o usly in mice was 500 trypanosomes per animal. Previous irradiation of rats with a dose of 900 R (followed by trans- plantation of medullary cells) had diminished the resistance of the animals. Thymectomy alone hardly changes the parasitaemia or mortality following T. cruzi infection. If irradiated and infected rats are thymectomized, 100% mortality is observed, whereas irradiation alone causes only 40% mortality. A single vaccination with T. cruzi irradiated with a dose of 100 kR does not protect mice from infection by a virulent strain (Telahuen). More than four inoculations of trypanosomes irradiated at 100 and 150 kR confer partial immunization. Immunized mice have no resistance to reinfection on the 285th day, although no mortality was observed. As regards revacci- nation, precautions should be taken in respect of storage of the trypanosomes at 4°C for more than 24 hours as from the time of irradiation since the possibility of restoration has been demonstrated. Inoculation of a non- pathogenic strain of T. gambiense into mice causes a slight delay in para- sitaemia, in comparison with that observed in non-vaccinated controls, but confers no protection. 137 In immunized mice the presence of a small number of agglutinating antibodies was established by the immuno-diffusion method. In hamsters the experiments did not yield results of interest because of the low senstivity of this species to T. cruzi (Tehuantepec). No protection against reinfection was observed in guinea-gips inoculated with irradiated T_. cruzi (Tehuantepec). Temporary changes in the endocytosis potential were demonstrated by electron microscopy in irradiated T. cruzi and C. luciliae. CONCLUSIONS < Experiments on vaccination with irradiated trypanosomes under defined experimental conditions show that immunity is only partial or temporary. It is essential to continue basic research on the antigen structure, morphology and physiology of irradiated trypanosomes. Inactivation by means of radio- mimetic agents opens up new prospects in immunization experiments relating to pathogenic protozoa. PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACT JADIN, J.M., CREEMERS, J., DUNJIC, A., Modifications ultrastructurales des Trypanosomidae causées par des irradiations, J. Protozool. Suppl. 17 (1970) 35; 9e Coll. Groupement des Protistologues de Langue Française, Aussois, 1970 (abstract). JADIN, J.M., LUMSDEN, W.H.R., DUNJIC, A., "Immunization against African trypanosomiasis by. irradiation and drug treated trypanosomes". XIe Congr. Protistologues de Langue Française, Lille, 1972. JADIN, J.M., LUMSDEN, W.H.R., DUNJIC, A., "Immunization against African trypanosomiasis by irradiation and drug treated trypanosomes". Reunion Société Belge de Protozoologie, Antwerp, 1972. VAN MEIRVENNE, N., LE RAY, D., JANSSENS, P.G., MAGNUS, B., "Immunogenic properties of common and variable antigens of T. brucei", Symp. London, 27 - 29 Sep. 1972. LE RAY, D., VAN MEIRVENNE, N., JADIN, J.M., "Immuno-electrophoretic characterization of common and variable antigens of Trypanosoma brucei", Symp. London, 27 - 29 Sep. 1972. 138 RESEARCH CONTRACT No. 1011 Summary of final report IAEA-R-916-F TITLE Identification of radiosensitive stages during the differentation of immunocompetent cells. RESEARCH INSTITUTION Institute of Microbiology, Czechoslovak Academy of Science, Prague, Czechoslovakia. PRINCIPAL SCIENTIFIC INVESTIGATOR J. Sterzl. PERIOD OF CONTRACT 1 June 1970 - 30 June 1973. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT Radiation-induced depression in immune response of an organism has been a subject of active research because of its possible significance in the case of organ transplantation and of its implication either as a limiting factor in radiotherapy of malignant diseases or as a possible cause of decreased viability after accidental exposure. It has been shown that a certain type of lymphocytes, i.e. immunocompetent cells, are involved in the immune response and that they exist under ordinary conditions as a mixture of cells, at various stages of differentiation, making it difficult to subject them to analysis. Taking advantage of germ-free animals in which cells remain undifferentiated before exposure to antigens, the present investigation was intended to elucidate the ontogenetic process of immuno- competent cells, using ionizing radiation as a tool at both whole animal and cellular levels. EXPERIMENTAL METHODS The animals used were conventional or germ-free mice, rats, rabbits and piglets. Three approaches were employed as follows: (1) Transfer of isologous lymphoid cells into lethally irradiated recipients for the study of (a) ontogenetic development of immunocapacity of lymphoid cells; (b) differentiation steps of lymphoid immunocompetent cells, of which antibody-forming cells were estimated by plague formation or by foci technique; and (c) genetic regulation of antibody response to be tested by use of poorly (CBA/J) and well (BIO. LP) responding strains of mice. (2) Determination of radiosensitivity of lymphoid cells at various stages of differentiation after immunization tested by the production of 19S 139 and 7S antibodies, the behaviour of immunocompetent cells in primary and secondary response, and the antibody response to pneumococcal polysaccharide type III in irradiated mice. (3) Use of newborn germ-free piglets for the studies on the significance of indigenous microflora in the development of radiation sickness and the effects of radiation on natural resistance. RESULTS OBTAINED 1. Studies with the transfer of lymphoid cells into lethally irradiated isologous recipients Studies on the development of the immunological capacity of cells isolated from the lymphatic organs and liver of 14 to 19-day-old mice embryos showed a strong dependence on the quantity of antigen. Antigen doses of 100 times higher than that for cells from adult animals were necessary for the induction of antibody response. The competence developed initially in the liver and after birth shifted into the intestinal lymphatics, then into the spleen. The rapid increase of immune capacity in postnatal life of conventional animals was found to result from the stimuli of natural environment via intestinal bacterial flora. The switch from IgM to IgG was proved to accrue in the colonies of antibody-forming cells, which developed after the transfer of lymphoid cells to lethally irradiated recipients. The genetic regulation of the antihapten response was found to be bound directly to the lymphatic cells. Antihapten antibodies were formed only in non-responding recipients (CBA/j), which had been repopulated by receiving a mixture of cells containing B cells from well-responding donor (BIO. LP). T cells from well-responding strain in combination with B cells from non-responding mice did not yield any positive antibody response. 2. Studies in mice irradiated at different stages after immunization A time period was found to exist after the primary as well as secondary immunization, in which sublethal irradiation did not depress IgM production but that of IgG. The proliferation of immunocompetent cells activated by antigen was examined by pulse and continuous labelling of each differentiation stage with 14C-thymidine. Proliferation was shown to start within 24 hours after antigen administration. Antibody-forming cells were recruited from the pool of proliferating cells later at 48 to 96 hours after immunization. Quite a different picture was shown with a highly metabolizable antigen, polysaccharide type SIII. Nearly 100% of antibody-forming cells were labelled by 14C-thymidine at immunization dose of 0. 1 /jg, while at a paralyzing dose of 10 to 100 /ug antibody-forming cells appeared at 5 to 10 days after immunization, of which only 50% are labelled, indicating the cells that appeared before the state of immunological paralysis differentiated directly without proliferation. 3. Studies using germ-free piglets Germ-free piglets irradiated with supralethal doses showed a three- fold increase in survival time compared with conventional controls. The 140 damage of intestinal mucosa, the penetration of coli, enhanced sensi- tivity to endotoxin, and a temporary depression in complement levels were concluded to be the main factors controlling the sensitivity of animals associated with microbes. CONCLUSIONS The radiosensitivity was determined of each differentiation stage of immunocompetent cells. The differentiation stage in which production of IgM switches to that of IgG was identified and analysed by means of cell transfer to lethally irradiated recipients. The cellular basis for the genetic regulation of immune response was elucidated as well as the ontogenetic development of immune response during embryonal and postnatal life. The role of cell proliferation in each individual differentiation phase was determined in relation to the antigens of different quality. The contribution of microbial flora and its significance in the impairment of immune response were established in animals exposed to supralethal doses of radiation. PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACT MEDLÍN, J., Studies on immune paralysis at the cellular level, Folia Microbiol. 16 (1971) 531. RfHA, I., Studies on the immunoglobulin structure on the surface of lymphoid cells, Folia Microbiol. 16 (1971) 532." KÍHOVA-SKAROVÁ, B., FÖHA, I., "Host genotype and antibody formation, " Current Topics in Microbiology and Immunology 57, Springer Verlag (1971) 159-87. HOLUB, M., HAJDU, I., TREBICHAVSKY, I., JAROSKOVA, L., Formation of lymphoid cells from local precursors in irradiated mouse omenta, Europ. J. Immunol. ^(1971) 465-70. MILER, I., MANDEL, L., MORAVEK, F., KRUML, J., KLEPALOVA, ]., Radiation sickness in young animals in the presence and absence of the microbial factor: course of the post-irradiation syndrome after irradiation with lethal doses in newborn conventional, germ-free and Escherichia coli-monoassociated piglets, Folia Microbiol. 17 (1972) 291-99. STERZL, J., NORDIN, A., "The common cell precursor for cells producing different immunoglobulins, " Cell Interaction and Receptor Antibodies in Immune Response (Proc. Symp. Helsinki, 1970) (1971) 213-30. STERZL, J., Clones of antibody forming cells and their dependence on T and B cells. Folia Biol. (Prague) (in press). SIMA, P., Studies on the proliferation activity of antibody formation using the continuous infusion of 14c thymidine, Folia Microbiol. 16 (1971) 532. STERZL, J., NORDIN, A., Demonstration of the common precursor for production of IgM and IgG antibodies, Folia Microbiol. 16(1971) 1. STERZL, J., TLASKALOVA, H., The cooperation of lymphoid cells during the induction of the immune response, Folia Microbiol. ¿6 (1971) 529. RIHOVA-SKAROVA, B., RIHA, I., Genetic control of the immune response. II. Quantitative and qualitative characterization of antihapten antibodies in readily and poorly responding strains of mice, Folia Microbiol. 17 (1972) 66. SÍHOVÁ-ákÁROVÁ, B., ÍÍIHA, I., Genetic control of the immune response. III. The participation of bone marrow and thymus cells and the effect of endotoxin on the antibody formation to haptens in well and poorly responding strains of mice. Folia Microbiol. r7 (1972) 95. TLASKALOVÁ, H., Colonization of intestinal tract in experiments (in Czech), Acta Hyg. Epidem. Microbiol., Suppl. 12 (1972) 48. 141 RESEARCH CONTRACT No. 1011 Summary of final report IAEA-R-1011-F TITLE The relative biological effectiveness of beta, X-rays, and 27.2 MeV deuterons for oxidative enzymes in epidermis. RESEARCH INSTITUTION Gerencia de Investigaciones, Comisión Nacional de Energía Atómica, Departamento de Radiobiología, Buenos Aires, Argentina. PRINCIPAL SCIENTIFIC INVESTIGATOR A.J. P. Klein-Szanto. PERIOD OF CONTRACT 1 May 1971 - 30 September 1973. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT Although a considerable amount of information is available on the RBE of different types of ionizing radiations for a large number of biological parameters, there are few comparative studies using skin or epithelial tissue as biological systems to be examined. In the present study the relative effectiveness of three types of radiations, i.e. X-rays (30 and 220 kVp), beta rays, and accelerated deuterons, was analysed using morphological and histoenzymic characteristics of epidermis as the biological parameter for comparison. To evaluate the radiation influence appearing in the exposed skin surface, various skin areas were irradiated using specially designed diaphragms specific to each type of radiation employed. Epidermal tissue responses were examined quantitatively by histological and histoenzymic techniques. This enabled numerical data obtained in situ on tissue samples to be provided free from the distortion that inevitably takes place during sample processing when using conventional biochemical techniques. EXPERIMENTAL METHODS Newly born Wistar rats were used for all experiments. Skin of the dorso-lumbar region was exposed to different types of radiation. The radiation sources were: a 250-kVp X-ray therapy machine and a P-1115 X-ray generator for hard and soft X-rays, a 20 mCi 90Sr nasopharyngeal applicator for beta irradiation and the Buenos Aires synchrocyclotron for deuteron beam irradiations. In all experiments 5 to 7 animals were irradiated, generally with a dose of 16 krad and sacrificed 4 days after irradiation, which proved to be the optimum post-irradiation time for studying the epidermal alterations. The irradiated skin and the neighbouring 142 area of skin as a control were processed to demonstrate oxidative enzyme activities by histochemical techniques. The same material was used for histometric measurements. The quantitative analysis of the enzyme reac- tion was performed with a Zeiss Cytoscan microspectrophotometer. Two parameters thus obtained were: (1) the total enzyme content, which is expressed in arbitrary units and represents the integral of optical densities of the epidermis strip under study from basal up to the superficial layers; and (2) the mean enzyme concentration, which is a ratio of the total enzyme content and the epidermal thickness. Enzymes examined were NADP, diaphorase, succinic dehydrogenase (SDH), lactic dehydrogenase (LDH) and glucose-6-phosphate dehydrogenase (G-6-PDH). RESULTS OBTAINED Similar effects were produced by 2.27-MeV beta rays and 220-kVp X-rays on the total amount of oxidative enzymes in epidermis, as well as on the mean enzyme concentration. The general pattern found in these irradiation experiences showed that SDH and LDH slightly increase in their total amount, yet a decrease in their concentration in the tissue can be noted, which is due to the marked epidermal swelling. This swelling seems not to influence greatly the amount of G-6-PDH and NADP diaphorase. Both enzymes showed a notable increase in their total amount and the mean concentration. Epidermis irradiated with a 26. 5-MeV deuteron beam exhibited the same general pattern of change, but the total enzyme content for all enzymes studied was higher than the values for those irradiated with beta rays at the same dose (approximately 1.5 times higher). Irradiation with soft 30-kVp X-rays produced a greater effect on enzyme activities than did harder 220-kVp X-rays. The study of the skin alterations as a function of size of the irradiated surface showed that in all irradiation conditions the area of the lesion was larger than the width of the diaphragm used (150, 300, 600 and 1200 |jm). With all the types of radiations under study the acanthotic reaction increased as the slit's width broadened and the enzyme amount in the skin changed considerably. Mean enzyme concen- tration for SDH increased as the split became smaller, while total enzyme content for SDH and especially for G-6-PDH increased as the exposed skin area increased. CONCLUSIONS It has been shown that histometric and histoenzymic parameters are adequate biological indices for the comparative study of radiation effects on the epidermis. No important differences have been found between hard X-rays and 2. 27-MeV beta rays on the oxidative enzyme activities of the Wistar rat's epidermis. Irradiation with soft X-rays or deuteron beam produced changes in enzyme activity of about 1. 5 times higher than those produced by hard X and beta radiations. With all types of radiation under study, the acanthotic reaction and the total enzyme content of the oxidative enzymes increased as the area of the exposed skin surface increased. On the other hand, the mean enzyme concentration of SDH decreased. With 143 all the types of radiations and slits used the width of the area of acanthotic reaction was larger than the exposed area. This might be due to the regenerative hyperplasia in the border region of the injured tissues. Thus, the dimension of the exposed epithelial surface is an important parameter, which should be carefully evaluated in any skin irradiation experiment, especially when a comparative analysis is involved. RBE values for epidermis in these parameters seem to depend not only on such factors as radiation energy, LET, OER, etc., but also on the extension of the treated skin surface. PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACT KLEIN-SZANTO, A.J.P., CABRINI, R.L., Acute response of oxidative enzyme systems in epidermis subjected to beta radiation; Arch. Dermatolog. Forsch. 243 (1972) 226-31. REY, B.M., KLEIN-SZANTO, A.J.P., A histometric study of acute radiation effects on rat tail epidermis, Strahlentherapie 143 (1972) 699-704. KLEIN-SZANTO, A.J.P., CABRINI, R. L., NOLLMANN, C., ITOIZ, M.E., Comparative study of epidermal oxidative enzyme changes after irradiation with X-rays, beta rays and a 26.5 MeV deuteron beam, Int. J. Radiat. Biol. 23 (1973) 189-90. ITOIZ, M.E., FRASCH, A.C.C., VOLCO, H.E., KLEIN-SZANTO, A.J.P., Microspectrophotometric study of acid phosphatase activity in irradiated squamous epithelium, submitted to Strahlentherapie. 144 RADIOLOGICAL SAFETY RESEARCH CONTRACT No. 530 Summary of final report IAEA-R-530-F TITLE Investigations on thermoluminescence dosimetry. RESEARCH INSTITUTION Health Physics Division, Bhabha Atomic Research Centre, Trombay, Bombay, India. PRINCIPAL SCIENTIFIC INVESTIGATOR A. K. Ganguly. PERIOD OF CONTRACT 1 June 1968 - 30 September 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT The application of stimulated thermoluminescence in solids to quantita- tive radiation dosimetry is now being studied intensively at many centres. Advantages of thermoluminescence detectors include high sensitivity, wide range and reproducibility of response, long shelf-life and small dimensions. They appear to be eminently suitable for a wide variety of applications includ- ing radiation protection surveillance and environmental radiation measure- ments. The purposes of the present investigation were (a) to select the most promising of locally available minerals such as fluorite, quartz, calcite and corundum; (b) to determine their sensitivities to different types of radiation and to study other related characteristics; (c) to prepare samples of calcium and lithium fluoride doped with selected minerals and to investigate their suitability for dosimetric applications; (d) to improve reproducibility by developing improved methods of fixing the powders; (e) to investigate the advantages and disadvantages of those detectors in applied radiation dosi- metry under the local climatic conditions. EXPERIMENTAL METHODS Detailed studies have been made of the thermoluminescence properties of natural fluorite and quartz, LiF (Mg), CaS04(Tm) and CaS04(Dy). The bulk specimens of the fluorite and quartz were crushed and sieved. Powder with grain sizes between 80 and 120 Tyler meshes was selected for use in the investigations. Crystals of LiF were obtained commercially and were 145 also grown in the laboratory. CaS04(Dy) and CaS04(Tm) were also pre- pared in the laboratory and again powder with grain sizes between 80 and 120 Tyler meshes collected. A new technique was developed for recording the glow curves. In this the powder was placed on a kanthal strip heated by an electric current and an iron-Constantan thermocouple spotwelded to the lower surface of the strip. Programmed linear heating was applied. A special filter was used to absorb the infra-red and visible red glow emission and new glow peaks were then recorded in LiF up to 400°C and in CaS04 and quartz up to 500°C. The glow curves were recorded for synthetic samples of LiF, CaS04 and Li2 B407, and for samples of natural fluorite, calcite, quartz, rocksalt, topaz and corundum. Emission spectra were also recorded for individual glow peaks of fluorite, calcite and synthetic CaS04 and LiF using a high light gathering power monochromator of the continuous scanning type. A study was made of the response to neutrons of samples of six materials that have thermoluminescent properties; the samples were embedded in layers of polyethylene 2 mm thick. A practical gamma-radiation dosimeter has been developed in which natural CaF2 powder is deposited on a kanthal strip. This dosimeter has been used for measuring the doses that the population living in the mono- zite sand areas of Kerala may receive. Measurements have so far been made on 10 000 persons and within 2500 houses. RESULTS OBTAINED The glow curves of individual samples of any particular materials were in general similar regardless of the origin of the sample, its colour and the impurities present. New glow peaks were recorded in LiF, which are of significance in explainingthe supra-linearity of the response, the sensitiza- tion and the pre-exposure annealing. Thermal activation energies were also determined for natural CaF2 samples. The thermoluminescence response of quartz is enhanced by heat treatment at temperatures above 600°C and by exposure of the samples to high levels of gamma radiation. When an irradiated sample is heated to a temperature less than that of its highest temperature glow peak, a part of the glow curve remains unre- leased. Studies were made on two effects of such'residual thermolumin- escence' for CaEj and LiF — the regeneration of already bleached-out peales at the expense of the residual peak by light, and modification of the response to radiation exposure. It was found that there is a transfer of thermolumin- escence in natural CaF2 from high temperature residual peaks to lower temperature peaks and a reverse transfer from lower to higher tempera- ture peaks. The efficiency of transfer is dependent on the temperature. Optically transferred thermoluminescence in CaF2 and CaS04 provides a basis for a useful method of dosimetry for ultra-violet light. The wavelengths of the emission spectra for CaF2 , CaS04 and LiF were the same in different glow peaks of the particular substance. The emission spectra for natural CaF2, CaS04(Tm) and CaS04(Dy) were identified as those of rare earth impurities. The study of the response of thermolumin- escent materials to neutrons showed that Li^B^^Mn) exhibited the highest neutron to gamma sensitivity ratio and CaSl the lowest. 146 CONCLUSIONS The emission spectral lines in the glow curves of natural CaF2, CaS04(Tm) and CaS04(Dy) can be attributed to rare earth impurities. It appears that the mechanism involves the reíase of holes from lattice centres and their recombination at the rare earth impurity sites. CaS04(Tm) and CaS04(Dy) are the most sensitive thermoluminescent materials for gamma radiation and are very suitable for use in dosimetry systems. The dopants appear to play the role of emission centres in CaS04 and the light emission corresponds to the excited states of trivalent dopant ions. Pink quartz is a very sensitive thermoluminescent material and its sensitivity can be enhanced by heating the samples to temperatures above 500°C and by exposing them to about 105R of gamma radiation. The optical transfer of thermoluminescence in CaF2 and CaSÓ4 provides the basis for an excellent method of dosimetry for ultra-violet light. Light green, transparent crystalline specimens of natural CaF2 possess high sensi- tivity to gamma radiation and are very suitable for the dosimetry of ionizing radiation and ultra-violet light. PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACT NAMBI, K.S.V., KATHURIA, S. P., SUNTA, C. M., "Radiation monitoring with a natural calcium fluoride thermoluminescent detector", Radiation Protection Monitoring (Proc. Seminar Bombay, 1968), IAEA, Vienna(1969). SUNTA, C. M., Thermoluminescence spectrum of gamma irradiated natural calcium fluoride, J. Phys. C. Solid State Phys. 3 (1970) 1978. NAMBI, K.S.V., KATHURIA, S. P., GANGULY, A. K., Thermoluminescence spectrum of a sample of natural CaFj powder, Ind. ]. Pure Appl. Phys. 8 (1970) 280. SUNTA, C.M., Optically produced thermoluminescence glow peaks in fluorite, Phys. Stat. Sol. 37 (1970) K81. SUNTA, C.M., KATHURIA, S. P., NAMBI, K. S.V., "Ultraviolet dosimetry by thermoluminescent fluorite", National Symposium on Radiation Physics, Trombay, 1970. SUNTA, C.M., DAVID, M., "Thermoluminescence of some mineral samples after gamma irradiation", National Symposium on Radiation Physics, Trombay, 1970. SUNTA, C. M., "Thermoluminescence of natural CaF2 and its applications". Third Int. Conf. Luminescence Dosimetry, Riso, 1971. SUNTA, C.M., KATHURIA, S.P., "Effects of residual thermoluminescence in fluorite and lithium fluoride thermoluminescent dosimers", Advances in Physical and Biological Radiation Detectors (Proc. Symp. Vienna, 1970), IAEA, Vienna (1971) 125. 147 RESEARCH CONTRACT No. 1011 Summary of final report IAEA-R-646-F TITLE Radon and SÍO2 toxicity on rats' lungs. RESEARCH INSTITUTION Institute of Occupational and Radiological Health, Belgrade, Yugoslavia. PRINCIPAL SCIENTIFIC INVESTIGATOR D. Panov. PERIOD OF CONTRACT 1 November 1968 - 30 November 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT In the research project it was planned to investigate the synergetic effect of radon and its decay products and Si02 on rats' lungs. Rats were examined and sacrificed after a short-term exposure of 3 months and after a long-term exposure of 9 and 18 months. EXPERIMENTAL METHODS Male Wistar rats, 2.5-3 months old, of average body weight around 190 g were used for this investigation. During the experimental period the animals were watered and fed with factory made standard food ad libitum. The animals were housed in cages in groups of 8. Before the exposure the animals spent 3 weeks in quarantine and during that time no changes were noticed by clinical observation. The rats were divided into four sub-groups: (1 ) Sub-group for radon inhalation 32 rats (2) Sub-group for quartz dust inhalation 32 rats (3) Sub-group for radon and quartz dust inhalation 32 rats (4) Control sub-group 32 rats / TOTAL 128 rats Two identical glass-walled chambers for radon and quartz dust inhala- tion were constructed with a volume of 1500 litres each. The chamber for inhalation of radon and its decay products was a hermetically closed system and during inhalation the microclimate was kept within tolerant limits. The parameters for the microclimate assessment were oxygen concentration, carbon dioxide concentration, moisture content and the temperature of the air. The chamber for quartz-dust inhalation represents an open system in 148 which the main factors of the microclimate are provided by constant air- flow provided by the operation of the aerosol generator (coefficient of ventilation 10-12). The total time of exposure lasted 18 months. Three times a week the animals were subjected to quartz-dust inhalation and three times a week to radon and its decay products. Quartz-dust exposure or radon exposure were every other day, for 5 h daily, which amounts to 1170 h of quartz- dust exposure and the same for radon and its decay products. Si02 was taken as quartz sand from the Rgotina mine. The physico/ chemical composition was: 98. 80% Si02, 0. 72% Al203, 0. 03% Fe203 and 14% clay. Material was milled and the average diameter of the particles was 40 microns. 90% of the particles inhaled had a diameter smaller than 3 microns. The dust concentration during the first six months was 50 mg/m3 and in the next 12 months it increased to 100 mg/m3. Particle size and count were made with an optical microscope. 226Ra was used as radon source. At intake in the inhalation chamber the radon concentration was 1 to 2 x 10~7 Ci/litre of air. The parameters investigated were: (1) body weight; (2) morbidity; (3) mortality; (4) fresh lung weight; (5) 21<)Po content in the lungs, liver, spleen and kidneys; (6) peripheral blood count; (7) blood coagulation; (8) bone marrow examination; and (9) pathological and histological changes in the internal organs. RESULTS OBTAINED The effects observed can be summarized as follows: The weight of silicotic lungs increases in proportion to the duration of exposure. The 120Po content of the lungs and kidneys is proportional to the duration of exposure. The reticulocyte count in the peripheral blood decreases after an 18-month exposure. There are signs of erythropoiesis inhibition in the bone marrow after an 18-month exposure. The lungs of the animals not exposed to dust show, after long-term inhalation of radon, hyperaemia, exuda- tion and infiltration of interstitium, whereas the lungs of animals exposed to dust and radon showed that radon inhalation induces the occurrence of a larger number of silicotic nodules and causes faster evolution of the nodules and more frequent confluence. No malignant alterations were found. 149 RESEARCH CONTRACT No. 1011 Summary of final report IAEA-R-791-F TITLE Chromosome aberrations in the peripheral blood lymphocytes of people living or working in areas of higher atmospheric concentration of natural radon-222 and its daughters in Badgastein, Austria. RESEARCH INSTITUTION Research Institute Gastein of the Austrian Academy of Sciences, Depart- ment of Radiology and Biophysics, Innsbruck, Austria. PRINCIPAL SCIENTIFIC INVESTIGATOR Johanna Pohl-Rüling. PERIOD OF CONTRACT 1 September 1969 - 30 September 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT The scope of the research project was to establish whether a threshold exists for the effect of low-level »-irradiation on biological systems. As «-irradiation source the natural radioactivity in the area of Badgastein, Austria, was used. It consists of an elevated content of radon-222 and its progenies in the atmosphere. The air activity is produced by the presence of about 20 thermal springs whose waters contain radon-222 up to 120 nCi/litre. For the biological effect of radioactive irradiation chromosome aberra- tions in the peripheral blood lymphocytes were chosen as an indicator of the absorbed dose. Many investigations on chromosome aberrations caused by gamma and X-rays have been carried out in various institutes, but only a few have dealt with a-irradiation. EXPERIMENTAL METHODS The research comprised two parts: (1) measurement of all environ- mental radioactive components and assessment of their contribution to the dose; and (2) investigation of chromosome aberrations in the peripheral blood lymphocytes of the population living and working in the area considered. To obtain significant mean values of the air activity, the contents of 222 220 214 212 222 218 214 212 Rn, Rn, Pb, Pb and the ratios of Rn: Po: Pb: Bi were measured in more than 2500 single samples from various places outdoors, indoors and in the mine. The variations of the indoor activity with 24 meteoro- logical parameters were investigated. The apparatus used consisted of: (a) 10-litre ionization chambers in connection with a vibrating-capacitor electrometer to measure the 222Rn content of the air sampled in the polyamid 150 sacks (50 x 50 cm); (b) single-filter devices to measure 214Pb, 212Pb and 210Pb and the ratio of 218Po: 214Pb: 214Bi; (c) double-filter devices consisting of one filter at the input and one filter at the output of a 25-litre decay chamber to measure 222Rn, 220Rn, 214Pb, 212Pb and 210Pb. The -/-background at various indoor points of the whole region was measured by radiophoto- luminescent glass dosimeters. The radiation burden caused mainly by the inhalation of 222Rn and its short-lived daughters was assessed according to previous experiments on animal and man. The resulting data were used to calculate the a blood dose due to the formula: 8 Dose in mrem/yr = 15 x 10" (Aj + \ + A3 ) A. = 222Rn content in pCi/litrex hours of stayx (1+10 ZJ* ¿ = real ventilation volume Cytogenetic investigation of the population A number of blood samples (10 cm3from arm vein) were obtained. Routine blood culture techniques were employed and, where possible, early harvests were scored. All deviations from the normal were noted, namely aneuploidy and polyploidy, chromatid aberrations — gaps, breaks, exchanges, chromosome aberrations - breaks, acentric fragments, minutes, dicentrics, rings and abnormal monocentric chromosomes (intra-arm and symmetrical interarm exchanges resulting in morphologically altered chromosomes). Only chromosome aberrations of the 'unstable1 type were included in estimations of the break rate. Deletions other than those accompanying multicentric chromosomes or rings were scored as one break, minutes, dicentric and ring chromosomes as two break events. The presence or absence of the accompanying acentric fragment was noted in all asymmetrical aberrations caused by two breaks. As an isochromatid break of the NuPD type cannot with certainty be distinguished from a terminal deletion, aberra- tions of this type, although scored separately, were counted as fragments in assessing the breakage rate. RESULTS OBTAINED According to the measured environmental radioactivity and the assessed a blood doses, the population investigated could be classified regarding their radiation burden into seven groups. Altogether 27 300 cells from 118 persons were analysed. The data demonstrate a dependency on age and sex for the analysed aberrations. To establish a dose-response curve an attempt was made to normalize the findings with regard to age. Within a single group cases, were divided into persons below and above 50 years of age. If the ages are a: and a2 and the percentages of aberrations p^^ and p2, the tentative normali- zation to 50 years was: (e^ 2-50)- (p2 -p^ / (a -a )• 151 CONCLUSIONS A dependence between internal dose from the inhalation of 222Rn and its daughters, and chromosomal aberrations in peripheral blood lymphocytes has been demonstrated in a population living and working within a region of elevated natural radioactivity. Chromosome aberrations and aneuploidy increase at alpha blood doses higher than 0. 3 rem/yr, corresponding, accord- ing to our calculations, to a continuous inhalation of air with a 222Rn content of 40 pCi and an average decay product ratio, and is commensurate with the maximum permissible dose values. This investigation suggests that a threshold for visible morphological signs, of radiation damage in the chromosomes of man exists. 152 RESEARCH CONTRACT No. 1011 Summary of final report IAEA-R-894-F TITLE Correlation of internal radiation doses from incorporated isotopes and chromosome aberrations. RESEARCH INSTITUTION Institute of Radiology and Radiation Hygiene, Sofia, Bulgaria. PRINCIPAL SCIENTIFIC INVESTIGATOR S. L. Todorov. PERIOD OF CONTRACT 1 May 1970 - 31 May 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT The induction of chromosome anomalies following irradiation exposure is being developed to enable chromosome analysis to be used as a biological indicator of radiation damage in man. Advances in radiation cytogenetics, particularly studies using external exposure, suggest that the method can similarly be applied to study chromo- some analysis in the case of internal exposure resulting from radionuclide uptake. Studies in this area have been very few since they necessitate a time-consuming program with experimental animals. Animal data may only be very cautiously extrapolated to man though the information gained would be an essential asset in quantifying radiation damage to genetic cell struc- tures in the case of prolonged exposures to low dose rates. The primary objective of the investigation involves the assessment of the type and magnitude of chromosome aberration induced following 89Sr intake by Wistar rats. EXPERIMENTAL METHODS Strontium-89, one of the biologically important radionuclides, was administered either by stomach tube or intraperitoneally. One femur was ashed and counted by scintillation techniques. Bone marrow from the other femur was taken to make the cytological preparations according to Ford' s method for chromosome aberration analysis. The dose to bone was estimated from skeletal radionuclide concentrations in ß Ci using the method recommended by the ICRP. In calculating the bone marrow dose Spires» corrections were made. The order of doses ranged from 27-400 rems in the case of ingestion and from 200-400 rems in the case of intraperitoneal ingestion. 153 RESULTS OBTAINED Owing to the relatively low skeletal accumulation coefficients and, hence, low absorbed doses after 89Sr ingestion, no significant deviation from sponta- neous aberration rates was observed in these experiments. . Most probably, at the low dose rates achieved the major reason for the non-occurrence of higher aberration yields was an efficient action of the repair mechanism together with elimination of a fraction of chromosome aberrations resulting from high rates and unsynchronous occurrence of cell division processes in bone marrow. When the intraperitoneal route was used, 89Sr skeletal deposition and bone doses were found to be higher than in the case of ingestion so that relatively small radionuclide activities needed to be administered compared with the required ingested activities. In these experiments aberration yields were observed to increase in direct proportion to dose. Treatment of experimental data by least-squares techniques showed a relationship described by the equation Y = (2. 115 ± 0. 07 ) x 10"4D + 0. 0183 aberrations per cell; X2= 1.1, P > 0. 80, for the case of a 24-hour exposure. For an exposure lasting 48 hours, Y = (9. 86± 2. 30) x 10"5D + 0. 04 aberrations per cell; X2=0. 83, P> 0.90. When a comparison was made between experiments carried out at similar levels of exposure for 24 and 48 hours, it became evident that the determining factor for the pattern of aberration production is whether or not the exposure time lies within one division cycle. If it does, the magnitude of aberration yields varies as a function of the amounts injected of the radio- nuclide. The results obtained are consistent with the statement by Brooks and McClellan on this point. The linear dependence of aberration yields on radionuclide activities injected may be described by the equation Y= 0. 164 ßCi/g b. w. +0. 0217 aberrations per cell. CONCLUSIONS Rat bone marrow cells appear to be a suitable model for quantitative evaluation of chromosome aberration induction by bone-seeking beta emitters when high activities are administered. Under these conditions aberration yields are linearly related to dose. The occurrence of chromosome aberra- tions is dependent on the dose accumulated during a single division cycle and yields are proportionally related to the amount of the radionuclide administered. Comparison between the coefficients of aberration yields in the case of external gamma-ray exposure and the coefficients for exposure following 89Sr uptake by bone revealed an abrupt reduction by a factor of about 17 in total aberration yields in the latter case. As regards qualitative changes, aberrations of exchange type were found to be very few and were seen only at the high dose levels used. This is a characteristic of chronic exposure to low-LET radiations. 154 RESEARCH CONTRACT No. 1011 Summary of final report IAEA-R-896-F TITLE Development of a method of selective measurement of thermal neutron and gamma-radiation exposures in a mixed radiation field for normal and accident conditions by means of thermoluminescent dosimeters of multiple use (part of a co-ordinated program on nuclear accident dosimetry). RESEARCH INSTITUTION Institute of Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Sofia, Bulgaria. PRINCIPAL SCIENTIFIC INVESTIGATOR I. T. Mishev. PERIOD OF CONTRACT 1 May 1970 - 31 May 1973. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT One of the most important problems in health physics and radiation protection is the dosimetry of mixed radiation. Due to the difference in RBE values, dose determination in mixed gamma-neutron radiation fields is diffi- cult. This difficulty arises especially where small dosimetry systems are necessary for personnel dosimetry. The scope of the project was to investi- gate the suitability of thermoluminescent dosimeters based on natural fluorite (CaF2 ), which is obtained on a large scale in Bulgaria, for the selective measurement of gamma and thermal neutron exposures in mixed radiation fields under normal and accident conditions. EXPERIMENTAL METHODS Dosimeters were prepared from both pure natural fluorite and homo- geneous mixtures of natural fluorite (marked as On) and lithium fluoride enriched to 90% in 6Li. The natural fluorite was ground and only the fraction of 0. 063 - 0. 071 mm/mm was used. The 6Li represented up to 25% of the total mass of mixture (a content of 25% 6Li corresponds to pure LiF). The 6Li was introduced to make use of the reaction ®Li (n,a )3H. To each mixture a 30% xylol solution of silicon varnish was added in the ratio 0. 6 cm3 solution toi g of mixture. Glass tubes of 30 mm length, 1 mm in diameter and 0.1 mm wall thickness were then coated with this suspension. The tubes were dried at 100°C for 30 min and then baked at 400°C for 20 min. Heating spirals of Constantan(30 ohm) were inserted in each tube. The tubes were mounted in small protective glass tubes and finally placed in opaque plastic tubes. 155 In addition to the dosimeters prepared on a glass base, a suitable techno- logy was elaborated for the preparation of thermoluminescent dosimeters on a Teflon base. These dosimeters were made of a mixture of three compo- 6 nents; (i) natural fluorite marked as On; (ii) lithium fluoride ( Li content of 15% of the total mass of the natural fluorite-lithium fluoride mixture); and (iii) Teflon powder with a particle size of 35 pm (30% - 80% Teflon con- tent in the total mixture). Using a press, tablets of 0. 2 g weight were formed, with a diameter of 12.7 mm and a thickness of 0. 4 mm. The tablets were subsequently tempered for one to two hours at 380°C. The response of the dosimeters to gamma and neutron radiation was investigated using a gamma-ray field from a 60Co source and the mixed radiation field in the thermal column of the IRT-2000 reactor in Sofia. The cadmium-ratio R^ was >1000 and the equivalent exposure dose rate due to thermal neutrons was eight times greater than that from gamma rays. For the dose evaluation the 'peak method' was applied, i. e. the ampli- tude of the maximum (third basic) in the glow curve of the phosphor was measured. A portable photometer constructed in the laboratory was used as a reader. (For the reading of the Teflon dosimeters a special heating system was developed for the reader. ) The average measuring time for one dosimeter was about one minute. RESULTS OBTAINED Natural fluorite — lithium fluoride - glass dosimeters With increasing 6Li content in the phosphor the gamma sensitivity Vy increases. With increasing 6Li content in the phosphor the sensitivity towards thermal neutrons Vn increases, reaching a plateau at 10-15%, and then decreases. The ratio of n-sensitivity to gamma sensitivity /Vj, has a maximum of 40 at 10-15% ®Li content. Dosimeters do not change their parameters with repeated use, i.e. 100 times. The accuracy in dose determinations is better than 20%. Natural fluorite — lithium fluoride — Teflon dosimeters Dosimeters with a Teflon content of less than 30% have a poor mechanical stability (6Li content in natural fluorite-lithium fluoride mixture: 10-15%). Dosimeters with a Teflon content of 50% have an optimum and also sufficient radiation sensitivity and good mechanical resistance. The dosimeter tablets have to be tempered for two hours at 380°C to ensure uniform sensibility. The deviation in dose evaluations is less than 20%. The minimum doses that can be measured are 50 mR for gamma rays and 50 mrem for thermal neu- trons. The dosimeters do not change their parameters after repeated use for 100 times. CONCLUSIONS For the quick selective measurement of gamma and neutron doses in mixed radiation fields of gamma and thermal neutrons at an accuracy of 20% a small and simple personnel dosimeter system can be used consisting of two parts: A gamma-sensitive dosimeter of natural fluorite and a mainly 156 neutron-sensitive dosimeter prepared from a homogeneous mixture of natural fluorite with lithium fluoride containing about 15% 6Li. By incorporat- ing 50% Teflon gamma doses down to 50 mR and thermal neutron doses down to 50 mrem can be measured. Study of this dosimeter system in the Agency1 s third international inter- comparison experiment in nuclear accident dosimetry showed that high n-doses and high gamma doses up to 300 R were successfully determined in mixed radiation fields. PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACT MISHEV, I. T., RADICHEVA, M. A., LEVI, S. M., The natural fluorite in the dosimetry of the mixed field of gamma rays and thermal neutrons, Health Phys. 23 (1972) 367. MISHEV, I. T., "The natural fluorite in the personnel gamma-neutron dosimetry", Regional study group meeting on Radiological and Environmental Protection, Istanbul, 20-24 Nov. 1972, IAEA/PL-522, to be published as an IAEA Report. MISHEV, I. T., LEVI, S.M., RADICHEVA, M. A., New thermoluminescent dosimeter for measurements in mixed radiation fields (in press). MISHEV, I. T., 'A neutron accident dosimetry system", Third IAEA intercomparison of NAD systems, Boris Kidric Institute, 14-25 May 1973, Vin£a, Belgrade. 157 RESEARCH CONTRACT No. 1011 Summary of final report IAEA-R-897-F TITLE Studies on factors affecting accuracy of individual dose measurement by means of radiophotoluminescent (R. P. L. ) and thermoluminescent (T. L. ) dosimetric systems (part of a co-ordinated program on nuclear accident dosimetry ). RESEARCH INSTITUTION Institute for Atomic Physics, Department of Dosimetry, Bucharest, Romania. PRINCIPAL SCIENTIFIC INVESTIGATOR Marieta Nicolae. PERIOD OF CONTRACT 1 April 1970 - 31 May 1973. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT Photoluminescent and thermoluminescent detectors have been intensively studied during the last 20 years. Because of their important character- istic features, such as direct proportionality between the radioluminescence and the dose over a wide range of doses, stability to environmental factors, small size, versatility, etc., these detectors have been rapidly developed and are now considered to be very useful in radiation protection and medical dosimetry. The aim of the project was to study various factors affecting the results of dose measurement with these solid integrator detectors, in order to improve the accuracy of the dosimetry. EXPERIMENTAL METHODS For the study of RPL dosimetric systems phosphate glass detectors made in Romania, called IFA DRL-1, were mostly used. They are manufactured as a rod with a diameter of 4 ± 0. 005 mm and a length of 7. 2 ± 0.1 mm. In some experiments French RPL phosphate glass detectors of the CEC-PB-31 and Pb-33 type and Japanese Toshiba glass detectors FD-3 were used. These detectors were exposed to gamma rays of 60Co or 137Cs under various condi- tions. For the reading of the IFA DRL-1 and CEC-PB-31 and PB-33 glass detectors, reading equipment designed at the Institute for Atomic Physics, Bucharest, was used. For the study of TL dosimetric systems TLD-100 lithium fluoride powder was used. The thermoluminescent powder sealed in small plastic caps was 158 exposed to 60Co gamma rays in the dose range 100 mrad - 100 rad under various conditions. The read-out of the exposed thermoluminescent powder was performed with a TLD reader designed at the Institute for Atomic Physics, Bucharest. Studies were made on the influence on the dose measurement accuracy of various factors, suchas: (a) stability of the reader; (b) variation of the output signals with repeated use of the detectors; (c) uniformity of the detectors and the geometry of the exposure conditions; and (d) temperature and time at storage after exposure, etc. The dosimeters were exposed in batches to the gamma-ray field under controlled conditions. RESULTS OBTAINED Some of the important results were as follows: The accuracy of the measurement of RPL signals does not depend on the detector size, but on the shape and the dimensional uniformity. The size of the glass detector rather influences the sensitivity. Therefore, the RPL signal increases with the diameter and decreases with the length of the glass rod. The reproducibility in predose and sensitivity can be greatly improved by using glass detectors with well-polished surfaces. No dependence on the dose rate was detected up to 2 x 105 rad/h. A signi- ficant dependence of the RPL sensitivity on dose rate was observed above 5 x 10s rad/h (about 15% at 5x 105 rad/h). RPL dosimetric systems exhibit very good stability with respect to the temperature of storage. The glass detector fades very slowly over a long- term storage. In routine dosimetry for radiation protection purposes no correction for fading is necessary for RPL dosimetric system at room tem- perature over a period of at least three months. A standard method of cleaning the glass detector must be employed before reading the exposure dose, especially in case of low dose measurements. Regeneration of the glass detectors by erasing the initial RPL signal by annealing for an hour at 380 - 400°C does not significantly affect the dose registration characteristics of the glass. In the case of the TL dosimetric system (lithium fluoride) the significant fluctuation in sensitivity was investi- gated after the regeneration (annealing) cycle by repeated use. CONCLUSIONS RPL glass detectors fade very slowly in long-term storage and the effect of temperature below 50°C was observed to be very small. With a good quality photomultiplier tube, a well-stabilized power unit and a well-controlled and stabilized u.v, source, the reading errors of phos- phate glass detectors can be kept within 2%. When the glass detectors are chosen for uniformity with a selected predose, the errors introduced by any non-uniformity are less than the reading errors. No significant variation in output was observed after repeated readings had been taken. 159 The results of the experiments on annealing the detectors by heating up to a higher temperature suggest that RPL dosimetric systems may be considered more reliable than TL dosimetric systems. The sensitivity fluctuation of the TLD lithium fluoride during the erasing cycle seems to be more important under the conditions of the experiment. For accurate dose measurement by this method a recalibration of the TLD powder is necessary after the annealing regeneration cycle. 160 RESEARCH CONTRACT No. 1011 Summary of final report IAEA-R-937-F TITLE Studies on the retention and the elimination of radioactive iodine from the human body. RESEARCH INSTITUTION Department of Clinical Therapeutics, Athens University School of Medicine, Alexandra Hospital, Athens, Greece. PRINCIPAL SCIENTIFIC INVESTIGATOR B. Malamos. PERIOD OF CONTRACT 1 August 1970 - 31 July 1973. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT Radioactive isotopes of iodine are the most commonly used in clinical medicine, hence the risk of accidental ingestion is considerable. Further- more, 131I is one of the fall-out contaminants following nuclear explosions, whether accidental, as in Windscale, or following the use of atomic weapons, as shown by the Bikini explosion and the contamination of some of the Marshall Islands. Fall-out contamination of the environment results in large doses of 131I being ingested with various food items, and the experience in the Marshall Islands has shown that thyroid nodules may be a late effect. It seems, therefore, desirable to devise a method for accelerating the elimination of radioiodine from the body both as a whole and also more speci- fically from the thyroid gland where it accumulates. To this end, stable iodide has been studied by several workers. If sufficient amounts of stable iodide are given before the radioiodine is taken up by the thyroid, then the thyroidal uptake is blocked and the ingested radioiodine is quickly excreted with the urine. This is effective and constitutes the procedure of choice when exposure to radioiodine may be foreseen. The problem is posed when treatment starts with some delay, that is after the radioiodine absorbed has already been taken up by the thyroid gland and organically bound. In these cases it is not enough to stop any further accumulation of radioiodine by the gland, but an attempt must be made for discharging what has already been taken up since the long biological half- life of iodine in the thyroid results in a high radiation to this organ, which is especially sensitive during childhood. EXPERIMENTAL METHODS In order to devise a scheme of treatment under these circumstances and accelerate the elimination of the radioiodine retained in the body, the 161 following agents have been given in groups of euthyroid persons undergoing radio- iodine function tests, starting 7 days after the oral administration of a 45-mCÍ dose of 131I: (1) Potassium iodide, 60 mg/d, 6 cases (2) Carbimazole, 40 mg/d, 8 cases (3) Potassium iodide, 30 mg/d with Carbimazole 40 mg/d, 6 cases (4) TSH, 10 i. u. i. m. on Days 7,8,9,11 and 13, 6 cases (5) TSH, 10 i, u. on Days 7,8,9,11 and 13 combined with Carbimazole 40 mg/d, 6 cases. The results have been compared with those obtained in a group of 8 con- trols not receiving any treatment. In all groups studied, the thyroidal, plasma protein-bound and urinary radioactivities were serially measured over a 14-day interval of time following 131I administration, that is one week before and one week during treatment. RESULTS OBTAINED The study of the composite radioiodine uptake curves in the various groups shows a drop after treatment on the seventh day. The decrease in thyroidal radioactivity can best be compared in the different groups if the biological half-life of 131I in the thyroid is cal-culated, separately for the first week, when no treatment is given, and the second week during actual treatment. It can be seen that in the controls the bio- logical half-life remained essentially unchanged. In the groups treated with potassium iodide, or Carbimazole with potassium iodide, there was a non- significant decrease in the biologic half-life. A more marked decrease, significant by the paired t test, was observed in the groups treated with either Carbimazole or TSH or TSH with Carbimazole. TSH appeared the most efficient agent for reducing thyroidal radioactivity, especially if com- bined with Carbimazole. The measurements of the mean PB131I values in the various groups showed that only in the group receiving TSH there was a significant increase 10,12 and 14 days after the administration of the tracer dose. The urinary excretion of radioactive iodine during the last 8 days of the study exceeded in all treatment groups the control values. The most marked excretion was obtained in the group treated with the combination of TSH and Carbimazole. In this group the urinary excretion exceeded significantly the amounts excreted in any other group. From this point of view, this treat- ment is the most effective one in eliminating radioactive iodine from the body. CONCLUSIONS It may be concluded from these results that all treatment schedules are effective in reducing the thyroidal radioactivity and increasing the elimina- tion of radioactive iodine, but that the most active treatment is the combina- tion of TSH and Carbimazole. With this treatment the doctor may achieve both a marked acceleration of the discharge of 131I from the thyroid, which 162 is the most vulnerable organ in these circumstances, and also a great increase in the urinary elimination of the isotope, thus reducing the whole body burden. It may, therefore, be summarized that when the subject is seen before any significant amounts of radioiodine are taken up by the thyroid, prevention of its accumulation is best accomplished by giving potassium iodide, starting with a minimum initial dose of 40 mg and continuing with at least 3. 3 mg of potassium iodide daily. If therapy is delayed, there is still room for treat- ment. The present results suggest that this is most successful if TSH injec- tions are combined with the oral administration of Carbimazole in doses sufficient to block the organically bound iodine liberated in the thyroid and the periphery. This procedure should be the one recommended when radio- active iodine is ingested accidentally. PAPERS PUBLISHED ON WORK DONE UNDER THE CONTRACT MALAMOS, B., KOUTRAS, D. A., LIVADAS, D.P., SFONTOURIS, J., "Comparison of methods for accelera- ting the elimination of radioactive iodine from the thyroid and the body", presented at 11th Int. Ann. Meeting Gesellschaft für Nuklearmedizin, Athens, 1973. 163 SAFEGUARDS RESEARCH AGREEMENT No. 942 Summary of final report 1AEA-R-942-F TITLE Study of a non-destructive measurement method for highly enriched U-Al alloy plate fuel. RESEARCH INSTITUTION Sumitomo Electric Industries Ltd. , Osaka, Japan. PRINCIPAL SCIENTIFIC INVESTIGATOR A. Nishiyama. PERIOD OF AGREEMENT 1 August 1970 - 31 July 1971. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT Simple, rapid and non-destructive methods of uranium assay of U-Al plates are desirable and useful during their fabrication process as well as for safeguards. Gamma-absorption techniques can be used to determine heavy element, i.e. uranium, content and the 185-keV gamma rays from the decay of 235U can be used to determine the 235U content when proper self-absorption corrections are made. The project served to examine these techniques in detail, with particular focus on the production of a standard calibration foil of uniform thickness, negligible self-absorption and known 235U content for the determination of the self-absorption correction and count rate/235U content conversion factors. EXPERIMENTAL METHODS After experimenting with vacuum evaporation, powder rolling, and electrodeposition methods for the preparation of the standard uranium foil, the electrodeposition method was found to be most suitable. The equipment was designed to electrodeposit the foil on only one surface. Three electro- lytes were studied, namely 500 ml of alkali salt carbonate (0. 15M K2C03 + 0. 15M KOH) plus 1 g uranyl nitrate, 500 ml of fluoride (0. 1M LiF) plus 1 g uranyl nitrate, and 500 ml of oxalate (0.4M NH4C203) plus 1 g uranyl nitrate. In addition, the electrodeposition was studied on various backing foils, temperatures and current densities. For the gamma-ray measurements of the standard foil as well as U-Al fuel plates, a collimated 3-in. dia. by 3-in. thick Nal(Tl) scintillation detector was used. Spectra were accumulated by means of a 200-channel pulse height analyser but the counting rate of the 185-keV peak was measured with a single-channel analyser and scaler. 167 235 The determination of the U content of a U-Al fuel plate (Wu) consists of the net 185-keV count rate of the standard foil (I), of the U-Al plate (R), and of the U-Al plate between the standard foil and the detector (C): A R * (~f1 R Wu = ws -, — As I (C - R - 1 235 where Ws is the U content of the standard foil, and Au and As are the respective areas of the U-Al plate and standard foil. For the determination of the uranium content of the U-Al fuel plates, a linear calibration curve for the 185-keV gamma transmission as a function of uranium content (g/cm2) was obtained; the measured mass absorption coefficient for uranium was 1.42 cm2/g. RESULTS Optimization of the electrodeposition method with the oxalate electrolyte resulted in the following: (1) Influence of electrodeposition temperature. The electrodeposition rate is low at a temperature of less than 60°C. Since the evaporation of the electrolyte at a temperature of more than 80°C is substantial and the electro- deposition rate increases only slightly, 70°C is considered to be an optimum temperature. (2) Influence of the ammonium oxalate concentration. The lower the ammonium oxalate concentration, the higher the rate of electrodeposition, but the electrodeposited surface is susceptible to peeling. Above 0. 2N the electrodeposition rate is only a weak function of the concentration but the bonding strength increases. Thus, a concentration of 0.4N is recommended. (3) Influence of current density. The electrodeposition rate is pro- portional to the current density but increased current density results in a rougher surface. A current density of 100 - 150 mA/cm2 was found to be optimum. (4) Influence of uranium nitrate concentration. When the concentration is greater than 4 g/litre, a black precipitate of the uranium oxide is produced and the electrodepositing surface becomes rough. (5) The chemical form of the electrodeposited material on the foil was found to be UsOg. (6) The amount of uranium deposited on the standard foil was 2 2 235 19. 73 mg/cm as U3Og or 15. 007 mg/cm as U. (7) The self-absorption of 185-keV gamma rays in the standard foil was calculated to be 0. 1%. Quantitative non-destructive analysis of two U-Al fuel plates resulted in: (1) 15. 35 ± 0. 24 g 235U as compared with 15. 41 ± 0. 05 g obtained by the conventional density measuring method and 15.38 g obtained from chemical analysis. (2) 15. 59 g 235U as compared with 13.79±0.25g obtained by the conventional density measuring method; the reason for this difference was traced to segregation of the uranium within the U-Al fuel plate. 168 CONCLUSIONS With the optimum electrodeposition parameters described, a standard 235 foil of uniform thickness, negligible self-absorption and known u content can be produced. Readily available instrumentation can be used for quanti- tative, precise and accurate non-destructive analysis on U-Al fuel plates. In addition, these non-destructive measurements can be used to investigate possible segregation of uranium within U-Al fuel. 169 RESEARCH CONTRACT No. 1011 Summary of final report IAEA-R-983-F TITLE Integral experiments restricted at key points of control for highly enriched fuel element cycle from fabrication plant to dissolver of reprocessing plant. RESEARCH INSTITUTION Centre d'Etude de l'Energie Nucléaire, CEN/SCK, Mol, Belgium. PRINCIPAL SCIENTIFIC INVESTIGATOR C. Beets. PERIOD OF CONTRACT 15 December 1970 - 14 December 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT Non-destructive assay techniques are a nuclear material safeguards tool of fundamental importance. They can be applied readily by inspectors on site; results of the measurements with them are available immediately; measured samples are the same after measurement. The precision and accuracy of measurements with them is quite adequate for many practical cases. It is important to develop safeguards procedures for applying non- destructive techniques to key points of control for highly enriched (high strategic value) fuel element cycles from the fabrication plant to the dissolver of the reprocessing plant. The scope of this project was to select the appropriate techniques of measurements at every key point of control to evaluate the performance of these techniques taking into account the precision and accuracy obtained, speed and cost of measurements to make conclusions and recommendations for the use of these techniques for safeguards purposes. EXPERIMENTAL METHODS Gamma-spectrometry with scintillation and semiconductor detectors was selected as the most suitable method for non-destructive measurements of fuel elements and assemblies, both fresh and after irradiation. Three essential improvements in the technique have been developed and used during the course of this project: (i) The use of a fuel plate as a very suitable gamma source for absorptiometry measurements of total U content. (ii) A procedure for the assay of whole fuel assemblies by means of only two specified measuring points. 170 (iii) A procedure, using two additional gamma sources, for geometry and time-of-measurement verification was also developed for simultaneous measurements of ten fuel plates. RESULTS OBTAINED Suitable procedures for safeguards verification measurements were developed and tested for the following key measurement points: (1) Storage of the platelets (before) laminating at Highly Enriched Fuel Fabrication Plant (2) Storage of the laminated plates at HEFFP (3) Fresh fuel element storage at HEFFP (4) Fresh fuel element storage at highly enriched fuel reactor (HEFR) (5) Gamma-irradiation facility (irradiated fuel storage, cooling time less 100 days) at HEFR (6) Spent fuel storage at HEFR (7) Spent fuel storage at reprocessing plant RP (8) Dissolver of reprocessing plant. The precisions and accuracies reached in most of the measurements described satisfy safeguards requirements. Some of the proposed techniques significantly reduce the measurement and handling time and thus increase the effectiveness of the inspector's work. CONCLUSIONS Most of the selected and developed techniques tested in the course of this project demonstrated that they are suitable for safeguards verification measurements. Most of them will be included in the Safeguards Technical Manual to be used by inspectors since they are generally applicable to the assay of U-Al plate type fuel with Agency-owned instrumentation. The results of these tests will be very useful for safeguards and also for operators. 171 RESEARCH CONTRACT No. 1011 Summary of final report IAEA-R-993-F TITLE Measurement of neutron decay constant in a highly subcritical reactor as a safeguard method. RESEARCH INSTITUTION Institute of Nuclear Energetics, Academy of Sciences, Minks-Sosni, USSR. PRINCIPAL SCIENTIFIC INVESTIGATOR A.K. Krasin. PERIOD OF CONTRACT 1 January 1972 - 31 December 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT Nuclear material in subcritical or critical systems is present in a very accessible form and sometimes in very large quantities. Safeguarding them is a rather difficult and as yet unsolved problem. It is particularly difficult in the case of irradiated fuel. Developing appropriate safeguards methods for such systems is therefore important. The authors investigated a new method of verifying the fuel content of critical assembly elements by measuring neutron decay constant (a) of the assembly. EXPERIMENTAL METHODS Pulsed neutron source is used to measure the prompt neutron decay constant (a) in a subcritical system, once with reference fuel elements and again with a batch of test fuel elements replacing the reference elements. If the values of ce agree in the two cases, under identical experimental conditions, one can conclude that the nuclear material content in the two batches is the same. It is thus possible to check a large batch of elements, including irradiated elements, in one operation. RESULTS OBTAINED The authors discuss the design specifications of a subcritical assembly to be used for checking fuel content of elements and precautions to be taken for safety. Measurements of a were made with 7 5% enriched U02 fuel, various numbers of assemblies being placed in turn in a tank of water. The authors 172 noted some uncertainty in a quantitative evaluation of fuel content in this kind of measurement. However, any difference in a that is greater than the measurement error, for two configurations of the assembly with the same number of elements (reference and test systems), would indicate a discrepancy in the amount of fuel in the two batches of elements compared. For example, a variation of 3% in the decay constant represents a 2% change in the amount of fuel present. CONCLUSIONS The proposed method makes it possible to establish whether there has been a leakage of fuel in a test batch of fuel elements. To estimate quantitatively and accurately the fuel content in an assembly, however, further study is required. 173 RESEARCH CONTRACT No. 1011 Summary of final report 1AEA-R-994-F TITLE Integral safeguards experiment at the Novo-Voronezh LWR Power Reactor Plant. RESEARCH INSTITUTION I.V. Kurchatov Institute of Atomic Energy, Moscow, and Novo-Voronezh Nuclear Power Plant, Voronezh Region, USSR. PRINCIPAL SCIENTIFIC INVESTIGATORS S.A. Skvortsov and L.I. Golubev. PERIOD OF CONTRACT 1 January 1971 - 31 December 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT The aim of the integral safeguards experiment was to demonstrate the application of safeguards at a nuclear power station of the Novo-Voronezh type, i.e. one containing a water-cooled and water-moderated reactor (WWR), and to show that such an application is compatible with the Agency's safe- guards procedures. The major incentive for the experiment was the high probability of export of these types of reactors within Eastern Europe. The experiment consisted of three main parts: (a) the integral experi- ment proper; (b) measurement of the reactor power output; and (c) gamma- spectroscopy of the irradiated fuel assemblies. The studies are a direct continuation of the methods and procedures developed for IAEA Research Contract No. 577 (1959). EXPERIMENTAL METHODS The nuclear material accounting system was used to prepare the nuclear material balance in the store, in the reactor and in the cooling pond, in addition to the power station as a whole. The accounting system is based on computer programs for determining the burn-up of uranium and build-up of plutonium in WWRs (see IAEA Research Contract No. 495 (1968)). The experimental methods used to verify the nuclear accounting data were measurement of the reactor power output — using the state's own instruments as well as a neutron flux density integrator; mass-spectrometric analyses of the irradiated fuel; and the isotopic correlation technique. Identification of the irradiated fuel assemblies was achieved with a television unit by viewing the manufacturer's assembly numbers, whilst gamma-spectroscopy was used to measure the mean burn-up of the assemblies. 174 RESULTS OBTAINED The integral experiment brought out the following important points with regard to the application of safeguards to WWRs. (a) The accounting system in normal use can be used as a basis for drawing up an overall nuclear materials balance with a discrepancy not exceeding 0.01%. (b) An accuracy of 4 - 5% is attainable in measuring the reactor thermal power. (c) Mass-spectrometric measurements can be used to calculate the isotopic composition of the irradiated fuel with an accuracy of 2%, and for calibrating the gamma-spectrometer so as to be able to apply the isotopic correlation method. (d) The Agency's questionnaire covers the information necessary for applying safeguards to WWRs. (e) It is essential to seal the reactor cover, the power meters and the counter that registers the number of fuel assemblies despatched from the station. (f) The time taken for identification of the manufacturer's assembly number is 20 minutes and to measure the burn-up at one point in the assembly takes 30- 35 minutes. (g) Identification of a batch of 100 fuel assemblies with an accuracy of ± 10% and 0. 95 probability from the burn-up requires measurements on 7 - 10 assemblies. (h) Proposals are made for the form and frequency of the reports to be submitted to the Agency. (i) Recommendations are made as to the inspection procedures and the frequency of inspection for nuclear power stations of the WWR type. CONCLUSIONS The experiment showed that if the .above recommendations on safeguards and inspection procedures are put into effect, it is possible to make a technical assessment as to whether or not nuclear material has been diverted from the station's fuel cycle with a 95% probability and a 3 - 5% accuracy. 175 RESEARCH CONTRACT No. 1011 Summary of final report IAEA-R-1025-F TITLE Tamper resistant instrumentation for a chemical reprocessing plant. RESEARCH INSTITUTION Braddock, Dunn and McDonald, Inc. , McLean, Virginia, USA. PRINCIPAL SCIENTIFIC INVESTIGATOR P. Boulay. PERIOD OF CONTRACT 7 June 1971 - 30 June 1973. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT The International Atomic Energy Agency, working in concert with the US Arms Control and Disarmament Agency (ACDA) and the US Atomic Energy Commission has focused attention on the safeguarding of special nuclear materials (SNM) during the fuel reprocessing stage of the nuclear fuel cycle. This involves the application of accountancy, surveillance and containment techniques. The weighting of importance of these safe- guarding methods is highly dependent on the characteristics of individual reprocessing plants but material accountancy is of major importance. This is so because it provides the mechanism whereby actual fuel through- put can be readily ascertained. The basic requirements for monitoring such an operation are: (1) the monitoring system should be independent of the plant monitoring facilities; (2) the monitoring system should be tamper-resistant; and (3) the monitoring system should be able to provide a continuous monitoring of the reprocessing plant throughput. Early in 1971 the IAEA, ACDA and USAEC expressed an interest in the possibility of testing prototype safeguards instrumentation in the General Electric Company's Midwest Fuel Recovery Plant (MFRP) with the refer- enced basic requirements in mind. This commercial facility, designed for reprocessing of irradiated fuel from light water reactors, has a rated capacity of 300 metric tons of uranium per year, producing UF6, plutonium nitrate and neptunium nitrate as products. Upon concurrence of GE to permit installation of such safeguards' monitoring devices, the IAEA and ACDA jointly provided funding to develop a prototype monitoring system, which would be installed in a key reprocessing vessel. The key vessel chosen was the V-101 Leacher Reservoir, which is also the MFRP input accountability vessel. The Plutonium Loadout vessel V-304 was also selected to provide measurement of one of the three output products. The development of the V-304 monitoring system was initiated upon completion of the V-101 system development and was funded entirely by ACDA. 176 The safeguards monitoring system, in order to provide accountancy, required the definition of the key measurement parameters that would allow the determination of the SNM solution volume and concentration per unit volume (density). The key measurement parameters are: liquid level (volume); differential pressure; and temperature. From these measure- ments can be determined: density of the SNM solute; specific gravity (temperature corrected); and the mass of SNM. These measurements and calculations, obtained independently from the plant measurements, canbe used to correlate with the plant information and to provide accountability verification. EXPERIMENTAL METHODS Based on the monitor system requirements and BDM's experience in the development of tamper-resistant data links, BDM proposed to develop systems for measuring liquid level, temperature and differential pressure in order to determine density and specific gravity for use in providing independently obtained accountancy information of SNM in a nuclear fuel reprocessing plant. A system was proposed which would measure liquid level and provide tamper-resistance utilizing Time Domain Reflectometry (TDR) techniques. The differential pressure and temperature are measured with appropriate commercial transducers. A unique single-probe concept was proposed to permit measurement of all the required parameters using a single vessel penetration. To measure liquid level in the probe utilizing TDR techniques, the probe design configuration and the cable connecting the probe to remotely located instruments were coaxial. A TDR instrument is used to measure the vessel liquid level, provide tamper monitoring and conduct special nuclear material surveillance. Connection to the ^monitoring system coaxial cable is made at the AIR-TDR- Thermocouple insertion manifold with a flexible and easily transported coaxial cable. The operating principle of the TDR instrument is best described from idealization of specific electrical circuit characteristics. The TDR signatures and theory applied are for the open and short circuit coaxial cables. In the case of the open circuit cable the reflection from an infinite load impedance is in phase with the transmitted energy, thus the reflected energy is twice the transmitted energy. For the short circuit cable the reflection from a zero-load impedance is opposite in phase with the trans- mitted energy, thus, the reflected energy is zero. When used with the Safeguard Secure Instrumentation Systems the liquid/air interface is determined by transmitting energy into the coaxial cable and observing reflections that occur. The vessel liquid is permitted to flow between the probe conductors, thus electrically shorting the two conductors together. Therefore, determination of the liquid/air interface in the sensor probe is simply a matter of monitoring the TDR reflection from a short-circuited coaxial cable. Liquid level is then determined by comparing this signature with calibrated signatures recorded from the same system without liquid and noting the net difference. For tamper monitoring the TDR is operated in the same manner except that the entire cable length is scrutinized. When tampers occur, the coaxial cable characteristic impedance can change in several ways yielding different TDR signature characteristics. 177 RESULTS OBTAINED Actual operating characteristics are not available; however, the theoretical prediction for the TDR resolution capability for two conditions are listed below. First is the resolution for liquid level changes of less than 1.2 inches; second is the resolution for liquid level changes greater than 1. 2 inches: (1) L.L. 1.2 in. = 0. 0240 ± 0. 0012 in. (2) L.L. 1.2 in. = 0.1441± 0.0012 in. The reason for this difference is the mechanical error of the position control that must be used when the TDR location of interest (liquid/air) interface moves off the oscilloscope display. This would be the situation when monitoring the liquid/air interface of sensitivities of 0. 12 inch per display division. CONCLUSIONS Because of GE/MFRP operational start-up delays, evaluation of the overall system performance has not been completed. During the develop- ment and installation period, a few tests were conducted to evaluate the system. Each of the process instruments is zero and range calibrated for the Leacher Reservoir and the instruments are tested for linearity. From these data tables and curves have been produced for inclusion in the operating manual. Actual volume calibration of the Leacher Reservoir has not been completed although useful MFRP correlation data are available. The thermocouple installation and Leacher Reservoir calibration are tasks that remain to be completed. The latter requirement may not be possible because of the tight pre-start-up scheduling experienced by MFRP. 178 RESEARCH CONTRACT No. 1011 Summary of final report IAEA-R-1072-F TITLE Fingerprinting and containment of fuel elements for safeguard of an Atucha-type reactor. RESEARCH INSTITUTION National Atomic Energy Commission, Buenos Aires, Argentina. PRINCIPAL SCIENTIFIC INVESTIGATOR M.A. Geiger. PERIOD OF CONTRACT 1 January 1972 - 31 December 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT The report discusses procedures based on item identification and containment for power reactors of the Atucha type, which has certain special features. Atucha is a heavy water moderated, cooled and reflected, natural uranium reactor. There are 253 fuel elements in the core and each has 36 fuel rods consisting of Zircaloy-4 tubes filled with natural U02 pellets. The reactor is fuelled continuously at the approximate rate of one element a day. Sealing of the reactor head is therefore not feasible in this case, and other measures need to be examined. The present project is a follow-up of Agency Research Contract No. 711 by Häfele and Gupta of Karlsruhe, which provides a theoretical background of the problems involved. EXPERIMENTAL METHODS No experiments were involved in the execution of the project. RESULTS OBTAINED Since the reactor uses natural uranium fuel, there is little incentive to remove fresh fuel elements. The possible exit routes for irradiated fuel are: (1) materials door; (2) personnel air lock; (3) emergency air lock; and (4) fuel transfer tube. (1) and (3) are meant to be used only in special cases of planned shut- down of the reactor or in emergencies; they can therefore be sealed. Removal through (2) is not feasible. The fuel element channel lock is the 179 only lock through which fuel elements can be introduced into the reactor and withdrawn from it. The lock therefore should be provided with a control system. The signals from the sensor of the fuel element identification system located at the entrance to the lock are transmitted to the power station process computer, where a complete history of each fuel element, giving its movements within the power station, its level of irradiation etc. , is stored. Each element has a stamped binary system number as its fingerprint, which is read by a microswitch and sensor, and the message, in the form of a sequence of 'zeros' and 'ones', is transmitted to the computer. The computer knows the direction of fuel movement and can thus, on the basis of information received, prepare the correct result. The problem of ensuring containment of fuel elements in the storage pool has not been solved satisfactorily yet and the authors suggest, for verification of records, spot checks of the elements during inspection. Visual checks of suitable identification marks on the elements by means of a periscope could be a useful measure, according to the authors of this report. The authors discuss the feasibility of gamma measurements on irradiated fuel assemblies in order to obtain various useful data. Measurements could be done with either scintillation or solid state detectors and two modes of measurement have been considered: (i) dynamic — scanning of elements as they pass through the transfer tube to the storage pool; and (ii) static — spectral measurement at a given point of the element (to estimate burn-up and Pu content) by keeping it stationary in a fixed position. CONCLUSIONS It is feasible to keep account of fuel element movements in an Atucha- type reactor automatically by means of a fuel identification and recording system. This system, together with the sealing of the materials door and the emergency air lock, would indicate any unauthorized removal of irradi- ated fuel from the reactor. Once the spent fuel reaches the storage pool, there is no effective containment. At this location spot checks of the elements during inspection are suggested by the authors for verification of records. Gamma scanning or gamma-spectrometric measurements of irradiated fuel, according to the authors, would involve many serious difficulties and would, in the present case, be of very limited practical value. 180 RESEARCH CONTRACT No. 1011 Summary of final report IAEA-R-1099-F TITLE Systems study on safeguards in enrichment plants. RESEARCH INSTITUTION Central Research Institute for Physics of the Hungarian Academy of Sciences, Budapest, Hungary. PRINCIPAL SCIENTIFIC INVESTIGATOR I. Kiss. PERIOD OF CONTRACT 1 December 1971 - 30 November 1972. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT Knowledge of specific features of uranium enrichment plants is required before consideration can be given to establishing the procedures for safe- guards implementation. At present there are no enrichment plants subject to international safeguards and therefore no practical experience is available on this important part of the nuclear fuel cycle. During the period 1969-1971 Safeguards Development Division carried out systems study work on enrichment plants and this was subsequently published as IAEA Report STR-14 (Rev. 1), "Safeguards in Enrichment Plants" (Parti), in October 1972. During these studies requirements became apparent for additional data covering likely enrichment plant parameters and their interrelationship, which were essential prerequisites to the study of the application of safeguards. The work reported in Part II of this report therefore is a continuation and extension of the work carried out by the Principal Scien- tific Investigator at the IAEA during 1969-1971. RESULTS OBTAINED The report consists of four separate sections: (1) The cascade. The following parameters have been calculated and tabulated for ideal cascades: The number of enrichment and stripping stages required to achieve specific enrichments of product and tails as a function of separation factor; The maximum theoretical enrichment and depletion as a function of the number of stages and separation factor; The magnitude of interstage flow rates for some selected cascades; 181 The average isotopic composition of cascades hold-up for selected cascades; The number of centrifuges per stage in selected cascades. The results are presented in the form of tables and graphs suitable for use in safeguards practice and are used as a basis for discussing the potential of cascades for the production of material of higher than normal enrichment and other topics of safeguards interest. (2) Inspection strategy. Consideration is given to the improvement in inspection effectiveness achieved by conducting a proportion of routine inspection visits without advance notification. This problem is analysed mathematically and the results presented in the form of a table and graphs showing the probability of detecting a diversion under varying conditions of equilibrium time of plant, number of regular and random inspections and length of uninspected period. (3) Dating of enriched uranium samples. In the enrichment process the uranium is purified of all its radioactive daughter products so that the subsequent accumulation of such products in the enriched uranium offers a possibility for its dating. A survey of the radioactive decay products of natural uranium isotopes and their method of measurement suggests that ages up to a 100 days could be determined by measurement of the 234Pa daughter of 238u and up to several years by measurement of the 231Pa and 227AC daughter of 235U . (4) Bibliography. About 500 references, covering the technical, economic and political aspects of uranium enrichment, are listed chronologi- cally under the following subject headings: (1) General and theoretical; (2) Economics, production forecasting. Plans for new plants. Policy; (3) Diffusion methods; (4) Centrifugation; (5) Other methods; (6) Analysis of enriched uranium; and (7) Safeguards. 182 RESEARCH CONTRACT No. 1011 Summary of final report IAEA-F-1209-R TITLE Optimization of safeguards effort. RESEARCH INSTITUTION Institut für Angewandte Systemtechnik und Reaktorphysik, Gesellschaft für Kernforschung mbH, Karlsruhe, Federal Republic of Germany. PRINCIPAL SCIENTIFIC INVESTIGATORS R. Avenhaus and D. Gupta. PERIOD OF CONTRACT 15 August 1972 - 15 August 1973. SCIENTIFIC BACKGROUND AND SCOPE OF PROJECT The application of games theory in the optimization of safeguards effort was studied with reference to a reprocessing facility and a mixed-oxide fabrication facility. The NFS facility at West Valley, New York, USA, was chosen as the reprocessing facility since the Agency has considerable data concerning safeguarding the NFS plant. The mixed-oxide facility chosen was the ALKEM plant at Karlsruhe, FRG, but since the full pro- duction line is not yet in operation, the data should be considered only as a representation of a typical mixed-oxide plant. The complete problem was known in advance to be not solvable analyti- cally; the major effort was devoted to various simplifying assumptions, which permitted solutions using Lagrange multipliers. Two six-month material balance periods were studied, with the inspector constrained to apply the same effort in both periods.. Number of batches 'diverted' and number of batches inspected were assumed to be continuous variables; both approximations proved to be quite good. However, the method used did not permit introduction of a boundary condition so that the number of inspection samples could not exceed the number of batches; this proved troublesome. Where the inspection effort was an appreciable fraction of the total possible effort, it was often necessary to set the effort in one or more material categories equal to 100%, and recalculate the optimization across the remaining categories. RESULTS OBTAINED Under the conditions specified (which are believed to be realistic) the optimum strategy for the inspector is independent of M, the total amount assumed to be diverted over the year. The optimum strategy is 183 influenced, however, by the assumed quantity diverted per batch. It is shown that there are practical and theoretical constraints on If the inspector knows, either from inspection data or from other independent evidence, that batch data has not been falsified, the inspection problem is one of estimating measurement uncertainties; this is called the Di case. If the inspector cannot preclude the possibility that within normal batch-to-batch variations the data may have been falsified, the batch variations must also be considered; this is called the D2 case. Where the inspector is concerned only with measurement uncertainties (the Dx case) inspector confidence is gained easily. In the range of 20-100% • of. full coverage no significant changes in probability of detection or amount diverted occur. For the two facilities studied an increase in inspection effort beyond about 3 0% of full coverage yields no significant improvement in inspector confidence. For the D2 case, however, decreased inspection effort leads to a rapid deterioration in inspector confidence. For the NFS plant, for example, decreasing inspection effort from 100 to 50% (and preserving a = ß = 0.05) increased M from 20 to almost 25 kg/yr. At 20% effort and M = 20 kg the probability of detection was only 40%. OD CO CD CM 184 HOW TO ORDER IAEA PUBLICATIONS Exclusive sales agents for IAEA publications, to whom all orders and inquiries should be addressed, have been appointed in the following countries: UNITED KINGDOM Her Majesty's Stationery Office, P.O. Box 569, London SE1 9NH UNITED STATES OF AMERICA UNIPUB, Inc., P.O. Box 433, New York, N.Y. 10016 In the following countries IAEA publications may be purchased from the sales agents or booksellers listed or through your • major local booksellers. Payment can be made in local currency or with UNESCO coupons. ARGENTINA Comisión Nacional de Energía Atömica, Avenida del Libertador 8250, Buenos Aires AUSTRALIA Hunter Publications, 58 A GippsStreet, Collingwood, Victoria 3066 BELGIUM Office International de Librairie, 30, avenueMarnix, B-1050 Brussels CANADA Information Canada, 171 Slater Street, Ottawa, Ont. K 1 AOS9 C.S.S.R. S.N.T.L., Spálená 51, CS-11000 Prague Alfa, Publishers, Hurbanovo námestie 6, CS-80000 Bratislava FRANCE Office International de Documentation et Librairie, 48, rue Gay-Lussac, F-75005 Paris HUNGARY Kultura, Hungarian Trading Company for Books and Newspapers, P.O. Box 149, H-1011 Budapest 62 INDIA Oxford Book and Stationery Comp., 17, Park Street, Calcutta 16 ISRAEL Heiliger and Co., 3, Nathan Strauss Str., Jerusalem ITALY Librería Scientifica, Dott. de Biasio Lucio "aeiou", Via Meravigli 16, 1-20123 Milan JAPAN Maruzen Company, Ltd., P.O.Box 5050, 100-31 Tokyo International NETHERLANDS Marinus Nijhoff N.V., Lange Voorhout 9-11, P.O. Box 269, The Hague PAKISTAN Mirza Book Agency, 65, The Mall, P.O.Box 729, Lahore-3 POLAND Ars Polona, Céntrala Handlu Zagranicznego, Krakowskie Przedmiescie 7, Warsaw ROMANIA Cartimex, 3-5 13 Decembrie Street, P.O.Box 134-135, Bucarest SOUTH AFRICA Van Schaik's Bookstore, P.O.Box 724, Pretoria Universitas Books (Pty) Ltd., P.O.Box 1557, Pretoria SPAIN Nautrónica, S.A., Pérez Ayuso 16, Madrid-2 SWEDEN C.E. Kritzes Kungl. Hovbokhandel, Fredsgatan 2, S-10307 Stockholm U.S.S.R. Mezhdunarodnaya Kniga, Smolenskaya-Sennaya 32-34, Moscow G-200 YUGOSLAVIA Jugoslovenska Knjiga, Terazije 27, YU-11000 Belgrade Orders from countries where sales agents have not yet been appointed and iHîtf Sliî requests for information should be addressed directly to: Publishing Section, International Atomic Energy Agency, Kärntner Ring 11, P.O.Box 590, A-1011 Vienna, Austria INTERNATIONAL ATOMIC ENERGY AGENCY VIENNA, 1974 PRICE: US $9.00 SUBJECT GROUP: VII Austrian Schillings 170,- Miscellaneous/IAEA General Activities (£3.80; F.Fr.43,-,- DM 23,-)