DOCSLIB.ORG

An Evaluation of Methods to Determine the Porosity of Calcium Phosphate Cements

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
An Evaluation of Methods to Determine the Porosity of Calcium Phosphate Cements An evaluation of methods to determine the porosity of calcium phosphate cements Johanna Engstrand Unosson, Cecilia Persson, Ha˚ kan Engqvist Division of Applied Materials Science, Department of Engineering Sciences, Uppsala University, Uppsala, Sweden Received 19 November 2013; revised 20 March 2014; accepted 30 March 2014 Published online 00 Month 2014 in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/jbm.b.33173 Abstract: The porosity of a material can be determined using phase transformation was observed at higher temperatures. a diversity of methods; however, the results from these The results also showed that drying for 24 h in vacuum was methods have so far not been compared and analyzed for sufficient to achieve water-free cements. The porosity meas- calcium phosphate cements (CPCs). The aim of this study ured was found to vary between the porosity methods eval- was to compare a fast and easy method for porosity meas- uated herein, and to get a complete picture of a cement’s urements with some commonly used porosity methods for porosity more than one method is recommended. Water CPCs. The investigated method is based on the assumption evaporation, is, however, a fast and easy method to estimate that when a wet cement sample is dried, the volume of the the porosity of CPCs and could simplify porosity measure- evaporated water is equal to the volume of pores within the ments in the future. VC 2014 Wiley Periodicals, Inc. J Biomed Mater cement. Moreover, different methods of drying the cements Res Part B: Appl Biomater 00B:000–000, 2014. were evaluated for acidic CPCs. The results showed that dry- ing at room temperature (22 6 1C) is preferable, since a Key Words: porosity, calcium phosphate, ceramic How to cite this article: Engstrand Unosson J, Persson C, Engqvist H. 2014. An evaluation of methods to determine the poros- ity of calcium phosphate cements. J Biomed Mater Res Part B 2014:00B:000–000. INTRODUCTION been made for CPCs. Compared to cements used for, for Calcium phosphate cements (CPCs) have been studied since example, construction, the CPCs have different setting reac- the early 1980s,1,2 and there is still plenty of ongoing tions, final phase composition, and setting times. There are research within this area. Since these cements are very simi- therefore reasons to believe that the CPCs do not behave in lar to the mineral phase of bone they have a high biocom- the same way during porosity measurement and drying as patibility. However, their main limitation in comparison to the construction cements. It is hence important to evaluate the more traditionally used acrylic cements are their the drying procedures and compare porosity measurements mechanical properties, leading to numerous studies focusing for CPCs when utilizing different porosity methods in order on improving the mechanical resistance of CPCs. Since the to determine which methods can be used and which should mechanical properties are strongly linked to the porosity be avoided. (and the pore size distribution) of ceramic materials,3,4 it is Porosity can be measured using a diversity of methods of high interest to have reliable and fast methods to deter- and depending on the material analyzed different methods mine the porosity of such materials. are more commonly used. For CPCs, mainly three methods Depending on the starting powders used, the CPCs can are utilized: helium pycnometry,8–10 mercury intrusion have either a basic or acidic setting reaction; the basic porosimetry (MIP),3,11,12 and using the tabulated density cements having precipitated hydroxyapatite (PHA) as the value of the material11,13–15 to calculate the porosity. The end product; the acidic cements having dicalcium phosphate main drawbacks of these methods are the destructiveness, dihydrate (brushite) and/or dicalcium phosphate anhydrous the long analysis times and the need for special equipment, (monetite) as their end products. Studies on methods to especially for MIP and helium pycnometry, which may entail determine porosity5 and obtain dry materials6 have been that fewer samples are analyzed, compromising statistical performed for cements used in the field of construction and power. Mercury is additionally expensive and toxic; requir- has furthermore been thoroughly reviewed in “Water Trans- ing careful handling, hence adding complexity to the port in Brick, Stone and Concrete” by Hall and Hoff.7 These method. The presence of amorphous phases and unreacted studies showed that the determined porosity is highly starting materials could furthermore give misleading results affected by the drying procedure and porosity method used. when using the tabulated density (presupposes a 100 pure However, to the authors’ knowledge, no such evaluation has and crystalline material) for the calculations. Correspondence to: J. E. Unosson (e-mail: [email protected]) Contract grant sponsor: FP7 NMP project Biodesign and the Swedish Research Council VC 2014 WILEY PERIODICALS, INC. 1 In this study, an alternative method to measure the samples are immersed in a solvent, normally water or alco- porosity of CPCs is compared to some common methods hol and the weight change is monitored until a constant used for CPCs and other types of cements. The new, alterna- weight is achieved. The porosity is then calculated according tive method utilizes the assumption that the volume of to Eq. (2), where msat is the weight of the sample saturated evaporable water in a wet sample is equal to the volume of with solvent, md is the dry weight, qsolvent is the density of the voids within the sample, the accuracy of which has not the solvent used, and Va is the apparent volume. been discussed before for CPCs. However, the method is commonly being used for other cements such as Portland ðmsat 2mdÞ=qsolvent 5,6 UðÞ% 5 Á 100 (2) cement and concrete. This method is the reverse of the Va water resaturation method, which is also frequently used for other types of cements,5,7 and the only equipment The next method used on other materials is solvent needed is a balance and a method to measure the sample exchange, where wet samples are stored in a new solvent volume (using, e.g., a caliper, or Archimedes method in (normally an alcohol) and the weight reduction is monitored 18 water or mercury), which makes it a fast and easy method during the exchange process. When a constant weight is for porosity measurements. achieved, the porosity is calculated according to Eq. (3), The aims of this study were to evaluate a few of the where mwater is the weight of wet sample, malcohol is the existing porosity methods and to develop a method for weight after complete exchange, qwater is the density of porosity measurements of CPCs that is fast, easy and cheap; water, and qalcohol is the density of the alcohol used. that is, do not require any advanced equipment. The method ðm 2m Þ=ðq 2q Þ should also include a drying procedure that does not result UðÞ% 5 water alcohol water alcohol Á 100 (3) in a compositional change for the investigated CPCs. Va All above discussed methods have the disadvantage of THEORY not being able to reach all pores. Depending on the radius When discussing porosity, different expressions are used for of the molecule used, different pore sizes can be reached; the density; and a clarification of the terminology follows. however, some pores will always be considered as closed Throughout this article, apparent density describes the den- pores and will not be taken into account in the calculations. sity of a sample when the outer dimensions are used to The density of the actual bulk material can in theory be cal- measure its volume. Skeletal density describes the density culated using molecular weight and crystalline lattice achieved when calculating the volume of the solid material, parameters received from X-ray diffraction (XRD) measure- excluding pores. ments.16 However, XRD calculations do not take into Two of the commonly used methods (i.e., tabulated den- account any amorphous phases that can be present in the sity and helium pycnometry) calculate the porosity of the sample and might therefore overestimate the skeletal material from the division of the apparent density with the density. skeletal density according to Eq. (1), where qa is the appa- rent density, and qs is the skeletal density. The apparent density is normally measured by immersion in mercury MATERIALS AND METHODS using Archimedes principle,11 or by measuring the outer Acidic CPC sample preparation diameters of the sample.3 Equimolar amounts of monocalcium phosphate monohy- drate (Scharlau) and beta-tricalcium phosphate (b-TCP, q Sigma-Aldrich) were thoroughly mixed with 1 wt % diso- UðÞ% 5 12 a Á 100 (1) qs dium dihydrogen pyrophosphate (SPP, Sigma-Aldrich). The powders were blended with 0.5 M citric acid (aq) in a liquid For basic CPCs it is common to use the tabulated density to powder ratio (L/P) of 0.3 mL/g, this L/P was chosen of the material [i.e., 3.16 g/cm3 for hydroxyapatite (HA)] as since it produces a very liquid paste with a long setting the skeletal density in Eq. (1).11,13–15 However, for the acidic time (i.e., 35 min initial setting time with the Gillmore nee- CPCs helium pycnometry is more commonly used.8–10 dle method19), from which air easily can escape. Defects Helium pycnometry measures the skeletal volume of the from mixing will hence be minimized. Both SPP and citric samples by determining the difference in helium pressure acid were added to retard the setting reaction. between an empty chamber with a calibrated volume and The cement paste was transferred to cylindrical rubber the chamber containing a sample.16 molds (Ø 6 mm, height 12 mm), and allowed to set for 40 The last, and most advanced, method used on CPCs is MIP, min at room temperature [RT, 22C(61C)].
Load more

Recommended publications
  • Effect of the Addition of Alginate And/Or Tetracycline on Brushite Cement Properties
    molecules Article Effect of the Addition of Alginate and/or Tetracycline on Brushite Cement Properties Claudia Morilla 1,2,3, Elianis Perdomo 4, Ana Karla Hernández 1, Ramcy Regalado 1, Amisel Almirall 1, Gastón Fuentes 1,2,* , Yaima Campos Mora 1,2, Timo Schomann 2,3 , Alan Chan 3 and Luis J. Cruz 2 1 Biomaterials Center, University of Havana, La Habana 10400, Cuba; [email protected] (C.M.); [email protected] (A.K.H.); [email protected] (R.R.); [email protected] (A.A.); [email protected] (Y.C.M.) 2 Translational Nanobiomaterials and Imaging Group, Department of Radiology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands; [email protected] (T.S.); [email protected] (L.J.C.) 3 Percuros B.V., 2333 CL Leiden, The Netherlands; [email protected] 4 Faculty of Automatic and Biomedical Engineering, Technological University of Havana, La Habana 11300, Cuba; [email protected] * Correspondence: [email protected] or [email protected] Abstract: Calcium phosphate cements have the advantage that they can be prepared as a paste that sets in a few minutes and can be easily adapted to the shape of the bone defect, which facilitates its clinical application. In this research, six formulations of brushite (dicalcium phosphate dihydrated) cement were obtained and the effect of the addition of sodium alginate was analyzed, such as its capacity as a tetracycline release system. The samples that contain sodium alginate set in 4 or 5 min Citation: Morilla, C.; Perdomo, E.; and showed a high percentage of injectability (93%).
    [Show full text]
  • Calcium Phosphate Bioceramics: a Review of Their History, Structure, Properties, Coating Technologies and Biomedical Applications
    Review Calcium Phosphate Bioceramics: A Review of Their History, Structure, Properties, Coating Technologies and Biomedical Applications Noam Eliaz * and Noah Metoki Biomaterials and Corrosion Lab, Department of Materials Science and Engineering, Tel-Aviv University, Ramat Aviv 6997801, Israel; [email protected] * Correspondence: [email protected]; Tel.: +972-3-640-7384 Academic Editor: Patrice Laquerriere Received: 11 February 2017; Accepted: 22 March 2017; Published: 24 March 2017 Abstract: Calcium phosphate (CaP) bioceramics are widely used in the field of bone regeneration, both in orthopedics and in dentistry, due to their good biocompatibility, osseointegration and osteoconduction. The aim of this article is to review the history, structure, properties and clinical applications of these materials, whether they are in the form of bone cements, paste, scaffolds, or coatings. Major analytical techniques for characterization of CaPs, in vitro and in vivo tests, and the requirements of the US Food and Drug Administration (FDA) and international standards from CaP coatings on orthopedic and dental endosseous implants, are also summarized, along with the possible effect of sterilization on these materials. CaP coating technologies are summarized, with a focus on electrochemical processes. Theories on the formation of transient precursor phases in biomineralization, the dissolution and reprecipitation as bone of CaPs are discussed. A wide variety of CaPs are presented, from the individual phases to nano-CaP, biphasic and triphasic CaP formulations, composite CaP coatings and cements, functionally graded materials (FGMs), and antibacterial CaPs. We conclude by foreseeing the future of CaPs. Keywords: bioceramics; biomineralization; bone cement; calcium phosphate; coating; composites; drug delivery; electrochemical deposition; functionally graded materials; nano-hydroxyapatite 1.
    [Show full text]
  • Role of Strontium on the Crystallization of Calcium Hydrogen Phosphate Dihydrate (CHPD)
    Journal of Minerals & Materials Characterization & Engineering , Vol. 10, No.7, pp.625-636, 2011 jmmce.org Printed in the USA. All rights reserved Role of Strontium on the Crystallization of Calcium Hydrogen Phosphate Dihydrate (CHPD) K. Suguna 1, 2 , C. Sekar 3* 1 Department of Physics, Sri Sarada College for Women, Salem -636 016, TN, India. 2 Department of Physics, Periyar University, Salem- 636 011, TN, India. 3 Department of Bioelectronics and Biosensors, Alagappa University, Karaikudi-630003, TN, India. *Corresponding Author: [email protected] ABSTRACT Calcium hydrogen phosphate dihydrate (CHPD, CaHPO 4· 2H2O) or brushite is found quite frequently in urinary calculi (stones) . Crystallization of brushite has been carried out in sodium metasilicate (SMS) gel with and without adding ‘Sr’ as additive. In pure system, dicalcium phosphate anhydrous (DCPA, CaHPO 4) or monetite and hydroxyapatite (HA, Ca 5(PO 4)3(OH)) grew along with brushite. The presence of Sr suppressed the formation of HA and enhanced the number and size of monetite crystals and changed the morphology of brushite crystals from needle shape to octopus-like shape. The samples were characterized by powder & single crystal X-ray diffraction (XRD), scanning electron microscopy (SEM), X- ray fluorescence spectroscopy (XRF), Fourier transform infrared spectroscopy (FTIR) and thermal analyses (TG-DTA) . Keywords: Brushite , Crystal growth, Sr additive, SEM. 1. INTRODUCTION Calcium phosphates have been studied extensively because of their occurrence in normal and pathological calcifications. Due to their excellent biocompatibility, it is a well-known bioactive material suitable for bone and hard tissue replacement [1] . Hydroxyapatite (HA, Ca 5(PO 4)3(OH), octacalcium phosphate (OCP,Ca 8H2(PO 4)6·5(H 2O)), tricalcium phosphate ( β- TCP, Ca 3(PO 4)2), dicalcium phosphate dihydrate or calcium hydrogen phosphate dihydrate (CHPD, CaHPO 4·2H 2O), dicalcium phosphate anhydrous (DCPA, CaHPO4), tetracalcium [2] phosphate (TTCP, Ca 4(PO 4)2O) and amorphous calcium phosphate (ACP) are different 625 626 K.
    [Show full text]
  • Inhibitors and Promoters of Stone Formation
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Kidney International, Vol. 13 (1978), pp. 361—3 71 Inhibitors and promoters of stone formation HERBERT FLEISCH Department of Pathophysiology, University of Berne, Berne, Switzerland Currently, three main mechanisms are thought to Crystal growth and crystal aggregation be important in the formation of urinary stones: 1) In the past, attention was devoted mostly to the the relationship between the concentration of the formation and growth of crystals. Recently, interest precipitating substances in urine and the solubility of has been directed to an area which, until now, had the mineral phase formed, 2) the role of promoters of been neglected: the crystal aggregation. This term crystallization and aggregation, and 3) the part describes the process of crystals binding one to an- played by inhibitors of crystal formation and aggre- other, resulting in the formation of larger clusters. In gation (Fig. 1). vitro, aggregation of both calcium oxalate [16, 17] Saturation of urine and calcium phosphate crystals [18] occurs readily when the solution is supersaturated. Aggregation It is now widely accepted that even in normal could be the mechanism which distinguishes simple people, urine is ordinarily supersaturated with re- crystalluria, which occurs in most normal people, spect to calcium oxalate [1—6], octocalcium phos- from stone formation. This line of thought is phate [2, 3], hydroxyapatite [1, 2], and sometimes strengthened by the finding that while usually only with respect to brushite [1, 7, 8]. The degree of individual calcium oxalate crystals are found in nor- supersaturation is usually higher in patients with mal people, stone-formers often excrete large aggre- urinary stones [2—4, 7—10].
    [Show full text]
  • Dicalcium Phosphate As a Mineral Supplement for Dairy Cows
    BULLETIN 455 AUGUST, 1930 Dicalcium Phosphate as a Mineral Supplement for Dairy Cows C. C. Hayden, C. F. Monroe, and C. H. Crawford OHIO AGRICULTURAL EXPERIMENT STATION Wooster, Ohio CONTENTS Introduction . • . • . • • . • • . • • • • • • . •.......•••.•.•••••••••••••• , • • . • • . • .. 3 Review of Other Work . .. .. .. 3 Metabolism Experiments . • . 3 Feeding Trials . 5 Experiment . 7 Plan ........................................................... 7 Cows Used ....................................................... 7 Care and Feeding . 7 Mineral Used . 8 Results ............................................................ 8 Milk Production ................................................. 8 Total Production ............................................ 9 Total Production Corrected to 4 Per Cent Fat Basis . 10 Corrected for Length of Lactation . • . 10 Corrected for Age . 11 Other Comparisons . 12 Periods Before and After Feeding Minerals Compared . 12 First and Second Lactations of Heifers Compared . 13 Summary of Milk Production . 13 Health of the Herd . 15 Condition of the Cows . 15 Breeding . • . 15 Diseases . ....................................... 16 General Discussion .................................................. 16 Summary and Conclusions ........................................... 18 References Cited .................................................... 19 Appendix • • . • • . • • • • . • . • . • • • . .•.•...••••••••••• , , • , , • , ....... 21 (1) Trumbull County Experiment Farm barn where the experiment was conducted DICALCIUM
    [Show full text]
  • Kidney Disease and Your Diet
    Kidney Disease and Your Diet Kidney Disease and Your Diet Department of Nutrition Services Kidney and Urinary Program 1 Kidney Disease and Your Diet PD 3085 (Rev 2015-10) File: peyles 2 Kidney Disease and Your Diet Inside this book Page About your kidneys 1 Protein 3 Potassium 6 Phosphorus 11 Sodium (Salt) 17 Herb and Spice Guide 21 Fluids 22 Staying a Healthy Weight 24 Bread, Grains and Other Starches 26 Fats 27 Sugar and Sugar Containing Food 28 Your Daily Choices 29 Sample Menu Plan 30 Tips on Eating Out 32 Reading Labels 39 3 Kidney Disease and Your Diet About your kidneys Your kidneys are shaped like kidney beans. Each one is the size of your fist. A kidney has about 1 million tiny filters inside. What do kidneys do? Kidneys have 3 main jobs . They filter and remove waste from blood and make urine. kidney = = filter out wastes in urine They control the salt and water balance in your body. They produce hormones that help make red blood cells and keep your bones healthy. What happens when kidneys have a disease? Kidney disease affects all the jobs that healthy kidneys do. Kidneys with a disease do not remove waste out of your body very well. Wastes start to build up in your body. Where does the waste come from? Waste comes from the food we eat. Our food is made up of proteins, fat and starches. When we eat food, the body digests it. The blood absorbs the digested food and takes it to all the cells to be used.
    [Show full text]
  • Chemical Specific Parameters May 2019
    Regional Screening Level (RSL) Chemical-specific Parameters Supporting Table April 2019 Contaminant Molecular Weight Volatility Parameters Melting Point Density Diffusivity in Air and Water Partition Coefficients Water Solubility Tapwater Dermal Parameters H` HLC H` and HLC VP VP MP MP Density Density Dia Diw Dia and Diw Kd Kd Koc Koc log Kow log Kow S S B τevent t* Kp Kp Analyte CAS No. MW MW Ref (unitless) (atm-m3/mole) Ref mmHg Ref C Ref (g/cm3) Ref (cm2/s) (cm2/s) Ref (L/kg) Ref (L/kg) Ref (unitless) Ref (mg/L) Ref (unitless) (hr/event) (hr) (cm/hr) Ref Acephate 30560-19-1 1.8E+02 PHYSPROP 2.0E-11 5.0E-13 EPI 1.7E-06 PHYSPROP 8.8E+01 PHYSPROP 1.4E+00 CRC89 3.7E-02 8.0E-06 WATER9 (U.S. EPA, 2001) 1.0E+01 EPI -8.5E-01 PHYSPROP 8.2E+05 PHYSPROP 2.1E-04 1.1E+00 2.7E+00 4.0E-05 EPI Acetaldehyde 75-07-0 4.4E+01 PHYSPROP 2.7E-03 6.7E-05 PHYSPROP 9.0E+02 PHYSPROP -1.2E+02 PHYSPROP 7.8E-01 CRC89 1.3E-01 1.4E-05 WATER9 (U.S. EPA, 2001) 1.0E+00 EPI -3.4E-01 PHYSPROP 1.0E+06 PHYSPROP 1.3E-03 1.9E-01 4.5E-01 5.3E-04 EPI Acetochlor 34256-82-1 2.7E+02 PHYSPROP 9.1E-07 2.2E-08 PHYSPROP 2.8E-05 PHYSPROP 1.1E+01 PubChem 1.1E+00 PubChem 2.2E-02 5.6E-06 WATER9 (U.S.
    [Show full text]
  • A Laboratory Study to Determine the Caries Lesion Remineralizing Potential of Novel Fluoride- and Calcium-Containing Toothpastes
    A laboratory study to determine the caries lesion remineralizing potential of novel fluoride- and calcium-containing toothpastes Frank Lippert, PhD*; Karmjeet K. Gill, BDS Indiana University School of Dentistry, Oral Health Research Institute, 415 Lansing St, Indianapolis, IN 46202 Corresponding author: Frank Lippert Indiana University School of Dentistry Oral Health Research Institute 415 Lansing St Indianapolis, IN 46202 [email protected] +1-317-274-3983 Author information: Dr. Lippert is an Associate Professor, Department of Cariology, Operative Dentistry and Dental Public Health, School of Dentistry, Indiana University, Indianapolis, IN. Dr. Lippert is also Director of the Remineralization Research Program, Oral Health Research Institute, School of Dentistry, Indiana University, Indianapolis, IN. Dr. Gill is a volunteer at the Oral Health Research Institute, School of Dentistry, Indiana University, Indianapolis, IN. Author contributions: FL designed the study, analyzed and interpreted the data, and co-authored the manuscript. KKG conducted the study, analyzed and interpreted the data, and co-authored the manuscript. FL and KKG approved the submission of the present manuscript. _______________________________________________ This is the author's manuscript of the article published in final edited form as: Lippert, F., & Gill, K. K. (2019). Carious lesion remineralizing potential of fluoride- and calcium-containing toothpastes: A laboratory study. The Journal of the American Dental Association, 150(5), 345–351. https://doi.org/10.1016/j.adaj.2018.11.022 Abstract Background. We conducted a laboratory study to determine the caries lesion remineralization and fluoridation potential of novel fluoride- and calcium-containing toothpastes. Methods. We created early caries lesions in bovine enamel specimens and assigned them to seven treatment groups based on their surface Vickers microhardness: Clinpro Tooth Crème, CTx4 Gel 1100, Enamelon Fluoride Toothpaste, MI Paste ONE, Crest Cavity Protection, and two fluoride-dose controls (low-F, high-F).
    [Show full text]
  • A Review on Calcium Pyrophosphate and Other Related Phosphate Nano Bio-Materials and Their Applications
    4R4ev. Adv. Mater. Sci. 48 (2017) 44-57 S. R. Vasant and M. J. Joshi A REVIEW ON CALCIUM PYROPHOSPHATE AND OTHER RELATED PHOSPHATE NANO BIO-MATERIALS AND THEIR APPLICATIONS Sonal R. Vasant1 and M. J. Joshi2 1Government Engineering College, Rajkot, Gujarat, India 2Department of Physics, Saurashtra University, Rajkot, Gujarat, India Received: July 29, 2016 Abstract. Over the past few decades, a little word with big potential has been rapidly insinuating into the world’s consciousness, nano. The nano-scale structures permit the control of funda- mental properties of the materials without changing their chemical structure. Living organisms can create amazing ways to produce high performance materials that involve not only creation of implants, replacing bone tissues and organs, but also synthesis of biologically active materials promoting the fullest restoration of tissues and maintenance of necessary functions of an organ- ism. In the biomaterial research field, nowadays, a great attention is given to bone substitute materials, particularly, calcium phosphate based bio-materials play important roles in clinical applications as it possesses high bio-compatibility and excellent ability to undergo varying de- grees of resorbability. These materials show a positive interaction with living tissue that includes differentiation of immature cells towards bone cells and also have chemical bonding to the bone along the interface, thought to be triggered by the adsorption of bone growth-mediating proteins at the bio-materials surface. In the present review paper an attempt is made to cover properties and applications of various phosphate nano bio-materials like calcium phosphate, calcium polyphosphate, calcium pyrophosphate etc over a time span right from 1920 to 2016.
    [Show full text]
  • A Thesis Entitled Development of High Strength Dicalcium Phosphate
    A Thesis entitled Development of High Strength Dicalcium Phosphate Anhydrous Cement with Nanosilica Sol by Timothy John Franklin Luchini Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Master of Science Degree in Mechanical Engineering _________________________________________ Dr. Sarit Bhaduri, Committee Chair _________________________________________ Dr. Ioan Marinescu, Committee Member _________________________________________ Dr. Mehdi Pourazady, Committee Member _________________________________________ Dr. Huan Zhou, Committee Member _________________________________________ Dr. Patricia R. Komuniecki, Dean College of Graduate Studies The University of Toledo December 2012 Copyright 2012, Timothy John Franklin Luchini This document is copyrighted material. Under copyright law, no parts of this document may be reproduced without the expressed permission of the author. An Abstract of Development of High Strength Dicalcium Phosphate Anhydrous Cement with Nanosilica Sol by Timothy John Franklin Luchini Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Master of Science Degree in Mechanical Engineering The University of Toledo December 2012 Dicalcium Phosphate Anhydrous (DCPA, Monetite) based materials have large potential as bone repair substitutes and drug delivery systems due to high bioactivity and known solubility in body fluid, and they could provide useful scaffolds in tissue engineering and orthopedic applications. Clinicians increasingly need bone scaffolds
    [Show full text]
  • New Knowledge of Chondrocalcinosis
    J Clin Pathol: first published as 10.1136/jcp.31.Suppl_12.214 on 1 January 1978. Downloaded from J. clin. Path., 31, Suppl. (Roy. Coll. Path.), 12, 214-222 New knowledge of chondrocalcinosis PAUL DIEPPE From the Department ofMedicine, University ofBristol There are three varieties of cartilage-hyaline, parathyroidism, haemachromatosis, hypothy- elastic, and fibrocartilage. Hyaline cartilage is the roidism, hypophosphataxia, hypomagnesaemia, precursor of bone. In the adult it is mainly found at gout(?), diabetes mellitus (?), Wilson's disease (?), bone ends, forming the load-bearing surface of ochronosis (?)). synovial joints. Extra-articular fibrocartilages such as those of the trachea and ribs often calcify with Historical perspective advancing age. Articular cartilage, however, usually remains free from mineral deposits. The term Intra-articular calcification has been recognisedforat 'chondrocalcinosis' may be defined as a pathological least a century. It was mentioned by Garrod (1876) state characterised by the precipitation of insoluble and by Adams (1872). With the advent of joint calcium salts in articular and periarticular cartilage. radiography there were a number of reports of The presence of chondrocalcinosis can be proved calcification of knee menisci (Pearson and Davin, only by crystallographic examination. Its presence 1921). Wolke (1935) described five cases from 2569 may be inferred by radiological examination or the knee radiographs. Zit'nan and Sifaj (1957) described discovery of crystals in synovial fluid. In addition, 12 cases, and they later identified familial cases with articular chondrocalcinosis is sometimes accom- polyarticular lesions and an associated arthritis by copyright. panied by arthritis. There are therefore three (2itnian and Silaj, 1976). separate phenomena associated with chondrocal- While 2ithan and Sifaj surveyed joint radiographs cinosis-radiological changes, crystals in synovial Hollander and McCarty (1961) examined joint fluid, and arthritis.
    [Show full text]
  • 2019 Trace Minerals
    United States Department of Agriculture Agricultural Marketing Service | National Organic Program Document Cover Sheet https://www.ams.usda.gov/rules-regulations/organic/national-list/petitioned Document Type: ☐ National List Petition or Petition Update A petition is a request to amend the USDA National Organic Program’s National List of Allowed and Prohibited Substances (National List). Any person may submit a petition to have a substance evaluated by the National Organic Standards Board (7 CFR 205.607(a)). Guidelines for submitting a petition are available in the NOP Handbook as NOP 3011, National List Petition Guidelines. Petitions are posted for the public on the NOP website for Petitioned Substances. ☒ Technical Report A technical report is developed in response to a petition to amend the National List. Reports are also developed to assist in the review of substances that are already on the National List. Technical reports are completed by third-party contractors and are available to the public on the NOP website for Petitioned Substances. Contractor names and dates completed are available in the report. Trace Minerals Livestock 1 Identification of Petitioned Substance 2 3 “Trace minerals” is a term for multiple nutritional elements added to livestock, poultry, and companion 4 animal diets in micro quantities only (i.e., measured in milligrams per pound or small units) (AAFCO 5 2019). While the Association of American Feed Control Officials (AAFCO) lists only cobalt, copper, iodine, 6 iron, manganese, and zinc as trace minerals added to animal feeds (AAFCO 2019), this technical report also 7 discusses chromium, molybdenum, and selenium, which are all commonly found in commercial trace 8 mineral products on the market for inclusion in animal feeds.
    [Show full text]