Abstract Development of a Teaching Coulometry
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University of Birmingham the Potential Impact of Essential
University of Birmingham The Potential Impact of Essential Nutrients Vitamins C and D upon Periodontal Disease Pathogenesis and Therapeutic Outcomes Brock, Gareth; Chapple, Iain DOI: 10.1007/s40496-016-0116-9 License: None: All rights reserved Document Version Peer reviewed version Citation for published version (Harvard): Brock, G & Chapple, I 2016, 'The Potential Impact of Essential Nutrients Vitamins C and D upon Periodontal Disease Pathogenesis and Therapeutic Outcomes', Current Oral Health Reports, vol. 3, no. 4, pp. 337-346. https://doi.org/10.1007/s40496-016-0116-9 Link to publication on Research at Birmingham portal General rights Unless a licence is specified above, all rights (including copyright and moral rights) in this document are retained by the authors and/or the copyright holders. The express permission of the copyright holder must be obtained for any use of this material other than for purposes permitted by law. •Users may freely distribute the URL that is used to identify this publication. •Users may download and/or print one copy of the publication from the University of Birmingham research portal for the purpose of private study or non-commercial research. •User may use extracts from the document in line with the concept of ‘fair dealing’ under the Copyright, Designs and Patents Act 1988 (?) •Users may not further distribute the material nor use it for the purposes of commercial gain. Where a licence is displayed above, please note the terms and conditions of the licence govern your use of this document. When citing, please reference the published version. Take down policy While the University of Birmingham exercises care and attention in making items available there are rare occasions when an item has been uploaded in error or has been deemed to be commercially or otherwise sensitive. -
Synergistic Antitumor Activity of Vitamins C and K3 on Human Bladder Cancer Cell Lines
Journal of Cancer Therapy, 2013, 4, 7-19 http://dx.doi.org/10.4236/jct.2013.46A3002 Published Online February 2013 (http://www.scirp.org/journal/jct) Synergistic Antitumor Activity of Vitamins C and K3 on Human Bladder Cancer Cell Lines Karen McGuire1, James M. Jamison1*, Jacques Gilloteaux2, Jack L. Summers1 1The Apatone Development Center, St. Thomas Hospital, Summa Health System, Akron, USA; 2Department of Anatomical Sciences, St Georges’ University International School of Medicine, K B Taylor Scholar’s Programme, Newcastle upon Tyne, UK. Email: *[email protected] Received April 24th, 2013; revised May 26th, 2013; accepted June 3rd, 2013 Copyright © 2013 Karen McGuire et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. ABSTRACT Exponentially growing cultures of human bladder tumor cells (RT4 and T24) were treated with Vitamin C (VC) alone, Vitamin K3 (VK3) alone, or with a VC:VK3 combination continuously for 5 days or treated with vitamins for 1 h, washed with PBS and then incubated in culture medium for 5 days. Co-administration of the vitamins enhanced the antitumor activity 12- to 24-fold for the RT-4 cells and 6- to 41-fold for the T24 cells. Flow cytometry of RT4 cells ex- posed to the vitamins revealed a growth arrested population and a population undergoing cell death. Growth arrested cells were blocked near the G0/G1-S-phase interface, while cell death was due to autoschizis. Catalase treatment abro- gated both cell cycle arrest and cell death which implicated hydrogen peroxide (H2O2) in these processes. -
Lecture Content
EMT 518: METHODS IN ENVIROMENTAL ANALYSIS III (2 UNITS) Lecturer: Professor O. Bamgbose SYNOPSIS Electro-analytical method: Potentiometry, Reference electrode – Calomel, Ag/Agcl, indicator electrodes – 1st, 2nd and 3rd order, Metal Electrodes, membrane electrodes – glass electrode, types of liquid junction potential, solid state electrode, potentiometric titration, end point location in potentiometric titration –visual, plot of E/V, plot of derivative curves 1st and 2nd electrogravimetry, fixed potential, constant current, constant cathode potential coulometry: constant current coulometry, coulometric titration. Voltammetry: classical polarography, Description of dropping mercury electrode, condition for polarographic determination, qualitative and quantitative analysis conductance methods: description of limiting ionic conductance, conductance cell, conductomertic titration. Thermal methods: Thermogravimetry, differential thermal analysis (DTA) LECTURE CONTENT POTENTIOMETRY Is a measurement of a given chemical species in an equilibrium system by the use of an electrode, while potentiometric titration is the technique that is used for following the changes in the concentration of chemical species as function of added titrant using an electrode. In both cases a cell is needed and a cell consists of the following: (1) Reference electrode (2) Liquid junction (3) Analyte solution (4) indicator electrode. It is also possible to have a cell without liquid junction. REFERENCE ELECTRODE. In carrying out a potentiometric determination the half cell potential of one electrode must be known which should be constant, reproducible and completely insensitive to the reference electrode and must be fully polarised throughout the duration of the measurement i.e the potential of the reference electrode does not change through the whole measurement. A classical example of reference electrode is the calomel electrode. -
Redox Interactions of Vitamin C and Iron: Inhibition of the Pro-Oxidant Activity by Deferiprone
International Journal of Molecular Sciences Article Redox Interactions of Vitamin C and Iron: Inhibition of the Pro-Oxidant Activity by Deferiprone Viktor A. Timoshnikov 1,*, Tatyana V. Kobzeva 1, Nikolay E. Polyakov 1 and George J. Kontoghiorghes 2,* 1 Institute of Chemical Kinetics & Combustion, 630090 Novosibirsk, Russia; [email protected] (T.V.K.); [email protected] (N.E.P.) 2 Postgraduate Research Institute of Science, Technology, Environment and Medicine, CY-3021 Limassol, Cyprus * Correspondence: [email protected] (V.A.T.); [email protected] (G.J.K.); Tel./Fax: +7-383-3332947 (V.A.T.); +357-2627-2076 (G.J.K.) Received: 21 February 2020; Accepted: 28 May 2020; Published: 31 May 2020 Abstract: Ascorbic acid (AscH2) is one of the most important vitamins found in the human diet, with many biological functions including antioxidant, chelating, and coenzyme activities. Ascorbic acid is also widely used in medical practice especially for increasing iron absorption and as an adjuvant therapeutic in iron chelation therapy, but its mode of action and implications in iron metabolism and toxicity are not yet clear. In this study, we used UV–Vis spectrophotometry, NMR spectroscopy, and EPR spin trapping spectroscopy to investigate the antioxidant/pro-oxidant effects of ascorbic acid in reactions involving iron and the iron chelator deferiprone (L1). The experiments were carried out in a weak acidic (pH from 3 to 5) and neutral (pH 7.4) medium. Ascorbic acid exhibits predominantly pro-oxidant activity by reducing Fe3+ to Fe2+, followed by the formation of dehydroascorbic acid. As a result, ascorbic acid accelerates the redox cycle Fe3+ Fe2+ in the Fenton reaction, which leads $ to a significant increase in the yield of toxic hydroxyl radicals. -
A Simple and Sensitive Assay for Ascorbate Using a Plate Reader
ANALYTICAL BIOCHEMISTRY Analytical Biochemistry 365 (2007) 31–39 www.elsevier.com/locate/yabio A simple and sensitive assay for ascorbate using a plate reader Jesse M. Vislisel, Freya Q. Schafer, Garry R. Buettner * ESR Facility and Free Radical and Radiation Biology, University of Iowa, Iowa City, IA 52242, USA Received 7 December 2006 Available online 7 March 2007 Abstract We have developed a rapid, inexpensive, and reliable assay for the determination of ascorbate using a plate reader. In this assay, ascorbic acid is oxidized to dehydroascorbic acid using Tempol (4-hydroxy-2,2,6,6-tetramethylpiperidinyloxy) and then reacted with o-phenylenediamine to form the condensation product, 3-(dihydroxyethyl)furo[3,4-b]quinoxaline-1-one. The rate of appearance of this product is monitored over time using fluorescence. With this method, it is possible to analyze 96 wells in less than 10 min. This permits the analysis of 20 samples with a full set of standards and blanks, all in triplicate. The assay is robust for a variety of samples, including orange juice, swine plasma, dog plasma, and cultured cells. To demonstrate the usefulness of the assay for the rapid determination of experimental parameters, we investigated the uptake of ascorbate and two different ascorbate derivatives in U937 cells. We found similar plateau levels of intracellular ascorbate at 24 h for ascorbate and ascorbate phosphate. However, the intracellular accumulation of ascor- bate via the phosphate ester had an initial rate that was three to five times slower than that via the palmitate ester. Only lower concen- trations of the palmitate ester could be examined because the ethanol needed as solvent decreased cell viability; it behaved similarly to the other two compounds at lower concentrations. -
All There Is to C • Vitamin C and Health the Vitamin C Essentials • Getting Your Vitamin C
Overview • Journey at C: Vitamin C in the Body All There is to C • Vitamin C and Health The vitamin C essentials • Getting Your Vitamin C Alexander Michels PhD • Vitamin C Myths Linus Pauling Institute Oregon State University May 11th, 2015 Journey at C Journey at C Vitamin C is Ascorbic Acid Vitamin C in the Small Intestine Ascorbic acid is vitamin C by definition: Only sources of ascorbic acid can cure scurvy. Image Source: Wikimedia Commons Extra vitamin C beyond the transport capacity passes through to the large intestine and may be lost Sodium-dependent Vitamin C Journey at C Transporters (SVCTs) Journey at C Vitamin C Intestinal Absorption Absorption and Vitamin C Transporters Ascorbic Acid Dehydroascorbic Acid (Oxidized form of Ascorbic Acid) Glucose Transporters (GLUTs) Remember: There is a limit to vitamin C absorption! 1 Note: Tissue ascorbic acid levels on this slide are hypothetical, but are driven by plasma vitamin C levels. As plasma levels increase, different tissues increase vitamin C Journey at C levels at different rates. The brain is given priority at low Journey at C vitamin C levels, while less essential organs are saturated Vitamin C in Tissues with vitamin C only at higher blood ascorbic acid levels. Vitamin C from Circulation to Tissues Plasma levels peak about 2 hours after a single dose. Vitamin C is transported into tissues when plasma levels rise. From Michels et al. Ann Rev Nutr 33 (2013) Vitamin C levels decline in the Journey at C plasma once kidney reuptake is Journey at C saturated, which also means that Vitamin C Urinary Excretion more passes through to the urine. -
Physical Electrochemical Software Brochure
Redefining Electrochemical Measurement Physical Electrochemistry Software The Physical Electrochemistry Software is used with a to the limit. You can define the potentials as absolute Gamry Potentiostat to perform in-depth studies of the voltages or by their relationship to the Open-Circuit structure of the electrode interface and the mechanisms Potential. of electrochemical reactions. The software brings Cyclic Voltammetry and other recognized electrochemical The scan rate (mV/s) is determined by the interval between research techniques to the Gamry user. The Physical data points (sample period) and the Step Size (mV): Electrochemistry Software is a useful tool for Step Size() mV fundamental studies, sensor development, small-scale Scan Rate() mV s = energy storage devices, electrophysiology, etc. Sample Period() s The minimum sample period may be as low as 3.3 µs. The This software incorporates the following electrochemical maximum Scan Rate is a function of Step Size. For techniques: example, the maximum Scan Rate with a 2 mV step is 600 V/s. Higher steps provide faster scan rates, but at the ••• Cyclic Voltammetry expense of resolution. Step Sizes greater than 10 mV are ••• Linear Sweep Voltammetry likely to result in unsatisfactory data. ••• Chronoamperometry ••• Repeating Chronoamperometry The Physical Electrochemistry Software can save, and ••• MMuullttiipplleeMultiple-Multiple---StepStep Chronoamperometry display, up to 262,143 data points! The number of CV ••• ChronopotentChronopotentiometryiioommeettrryyiometry cycles that can be displayed is dependent upon the scan ••• Repeating Chronopotentiometry parameters. ••• Chronocoulometry Step Size() mV No. of Cycles =262,143 × ••• Controlled Potential Coulometry Voltage Span of theCV() mV Like most Gamry software, the Physical Electrochemistry Software and a Gamry Potentiostat use the Framework for data acquisition and the Echem Analyst for data analysis. -
Stationary Electrode Voltammetry and Chronoamperometry in an Alkali Metal Carbonate-Borate Melt
AN ABSTRACT OF THE THESIS OF DARRELL GEORGE PETCOFF for the Doctor of Philosophy (Name of student) (Degree) in Analytical Chemistry presented onC (O,/97 (Major) (Date) Title: STATIONARY ELECTRODE VOLTAMMETRY AND CHRONOAMPEROMETRY IN AN ALKALI METAL CARBONATE - BORATE. MFT T Abstract approved: Redacted for Privacy- Drir. reund The electrochemistry of the lithium-potassium-sodium carbonate-borate melt was explored by voltammetry and chrono- amperometry. In support of this, a controlled-potential polarograph and associated hardware was constructed.Several different types of reference electrodes were tried before choosing a porcelain mem- brane electrode containing a silver wire immersed in a silver sulfate melt.The special porcelain compounded was used also to construct a planar gold disk electrode.The theory of stationary electrode polarography was summarized and denormalized to provide an over- all view. A new approach to the theory of the cyclic background current was also advanced. A computer program was written to facilitate data processing.In addition to providing peak potentials, currents, and n-values, the program also resolves overlapping peaks and furnishes plots of both processed and unprocessed data. Rapid-scan voltammetry was employed to explore the electro- chemical behavior of Zn, Co, Fe, Tl, Sb, As, Ni, Sn, Cd, Te, Bi, Cr, Pb, Cu, and U in the carbonate-borate melt. Most substances gave reasonably well-defined peaks with characteristic peak potentials and n-values.Metal deposition was commonly accompanied by adsorp- tion prepeaks indicative of strong adsorption, and there was also evi- dence of a preceding chemical reaction for several elements, sug- gesting decomplexation before reduction. -
COULOMETRY for the DETERMINATION of URANIUM and PLUTONIUM: PAST and PRESENT by M.K
BARC/2012/E/001 BARC/2012/E/001 COULOMETRY FOR THE DETERMINATION OF URANIUM AND PLUTONIUM: PAST AND PRESENT by M.K. Sharma, J.V. Kamat, A.S. Ambolikar, J.S. Pillai and S.K. Aggarwal Fuel Chemistry Division 2012 BARC/2012/E/001 GOVERNMENT OF INDIA ATOMIC ENERGY COMMISSION BARC/2012/E/001 COULOMETRY FOR THE DETERMINATION OF URANIUM AND PLUTONIUM: PAST AND PRESENT by M.K. Sharma, J.V. Kamat, A.S. Ambolikar, J.S. Pillai and S.K. Aggarwal Fuel Chemistry Division BHABHA ATOMIC RESEARCH CENTRE MUMBAI, INDIA 2012 BARC/2012/E/001 BIBLIOGRAPHIC DESCRIPTION SHEET FOR TECHNICAL REPORT (as per IS : 9400 - 1980) 01 Security classification : Unclassified 02 Distribution : External 03 Report status : New 04 Series : BARC External 05 Report type : Technical Report 06 Report No. : BARC/2012/E/001 07 Part No. or Volume No. : 08 Contract No. : 10 Title and subtitle : Coulometry for the determination of uranium and plutonium: past and present 11 Collation : 34 p., 2 figs., 7 tabs. 13 Project No. : 20 Personal author(s) : M.K. Sharma; J.V. Kamat; A.S. Ambolikar; J.S. Pillai; S.K. Aggarwal 21 Affiliation of author(s) : Fuel Chemistry Division, Bhabha Atomic Research Centre, Mumbai 22 Corporate author(s) : Bhabha Atomic Research Centre, Mumbai - 400 085 23 Originating unit : Fuel Chemistry Division, BARC, Mumbai 24 Sponsor(s) Name : Department of Atomic Energy Type : Government Contd... BARC/2012/E/001 30 Date of submission : December 2011 31 Publication/Issue date : January 2012 40 Publisher/Distributor : Head, Scientific Information Resource Division, Bhabha Atomic Research Centre, Mumbai 42 Form of distribution : Hard copy 50 Language of text : English 51 Language of summary : English, Hindi 52 No. -
Plutonium Analysis from Controlled-Potential Coulometry for the Certification of the MP3 Standard Material
P5_14 Plutonium analysis from controlled-potential coulometry for the certification of the MP3 standard material. A. Ruas, V. Dalier, J. Pivato CEA-Marcoule BP 17171 30207 Bagnols-sur-Cèze Cedex, France [email protected] Abstract – For contributing to the certification of the new metal plutonium reference material (MP3), controlled-potential coulometry (CPC) has many advantages: it is a high accuracy absolute chemical analysis technique. Many studies are now conducted on plutonium solutions, to improve the operating conditions and the current apparatus, for mass determination with a precision of 0.1%. The different experimental preliminary results are discussed and the apparatus described. The coulometry cell assembly comprises a motor connected to a stirrer designed to prevent splashing, an inlet tube for inert gas, three electrodes, and a thermocouple for measuring the temperature. The measuring system includes a potentiostat, a CPU, a calibrated current generator, a temperature indicator and a voltmeter, all maintained at a constant temperature. Current integration is made by electronic components, introduced in the potentiostat and the CPU. + − + INTRODUCTION Pu 4 + e ↔ Pu 3 (1) Experimental electrolysis is performed using a Coulometry is an assay method in which the metal electrode with a large surface area quantity of the element analyzed is determined (working electrode) immersed in the test by measuring a quantity of electricity; under solution. The quantity of electricity used for the certain conditions it is capable of providing a conversion is related to the quantity matter in very accurate determination of the plutonium solution by Faraday’s law of electrolysis: mass concentration. The advantage of this M method is that it is absolute and uses only small m = ⋅Q (2) masses of material. -
School of Engineering and Science to My Beloved Parents Abstract
Hybrid Organic-Inorganic Polyoxometalates Functionalized by Diorganotin Groups by Firasat Hussain A thesis submitted in partial ful¯llment of the requirements for the degree of Doctor of Philosophy Approved, Thesis Committee: Prof. Ulrich Kortz (Mentor), IUB Prof. Ryan M Richards, IUB Dr. Michael H Dickman, IUB Prof. Michael T Pope Georgetown University, U.S.A. Prof. Emmanuel Cadot Universit¶ede Versailles, France Date of defense: 19 May 2006 School of Engineering and Science To my beloved parents Abstract Polyoxometalates (POMs) are a well-known class of inorganic metal-oxygen clusters with an unmatched structural variety combined with a multitude of properties. The search for novel POMs is predominantly driven by exciting catalytic, medicinal, material science and bioscience applications. However, the mechanism of action of most polyoxoanions is not selective towards a speci¯c target. In order to improve selectivity it appears highly desirable to attach organic functionalities covalently to the surface of polyoxoanions. The hydrolytic stability of the Sn-C bond enables the synthesis of a novel class of polyoxoanions via attachment of organometallic functionalities based on Sn(IV) to the surface of lacunary polyoxoanion precursors. III III By reacting (CH3)2SnCl2 with Na9(®-XW9O33) (X = As , Sb ) in aqueous acidic medium leads to the formation of 2-D solid-state structures with inorganic and organic surface, which are rare examples of discrete polyoxoanions. (CsNa4f(Sn(CH3)2)3O(H2O)4 (¯-AsW9O33)g¢5H2O)1 (CsNa-1) and the isostructural (CsNa4[(Sn(CH3)2)3O(H2O)4( ¯-SbW9O33)]¢5H2O)1 (CsNa-2)It has been synthesized and characterized by multinu- clear NMR spectroscopy, FTIR spectroscopy and elemental analysis. -
Chronoamperometry
Chronoamperometry • Stationary electrode • Unstirred = mass transport by diffusion • Constant potential • Measure current vs time Theory assume Ox + n e- Red - both Ox and Red are soluble - reversible reaction (electrochemically) - potential set so reduction goes to completion at the electrode surface Components of output signal in Chronoamperometry IFar decreases because Ox used up at electrode surface and Ox is only replenished by diffusion Faradaic current (IFar) follows Cottrell equation I Capacitive current (Icap) (current) decays exponentially for a constant applied potential t (time) Icap is high as electrode capacitive layer charges up, then drops off Processes perturbing system can cause data to differ from Cottrell Equation 1) Capacitive Current – charging current is exponential as shown -kt Icap = e Note: Capacitive current decreases more rapidly than Faradaic current so at longer times the ratio IFar/Icap is larger 2) Occurrence of coupled chemical reactions e.g. Ox + n e- Red 2 Red A A + n e- B Affects the shape of the current-time curve Chronoamperometry Applications • Can measure concentration by measuring I vs conc. at any fixed time • Can analyze the shape of the current-time curve in order to study coupled chemical reactions • There are better ways to do both of these with more modern techniques • Chronoamperometry is important because it is a fundamental method on which other techniques are based Chronopotentiometry • Stationary electrode • Unstirred = mass transport by diffusion • Constant current applied between