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Study Of 2,5-Diaminoimidazolone, A Mutagenic Product Of Oxidation Of Guanine In Dna, Hannah Catherine J. Pollard Dec 2017

Study Of 2,5-Diaminoimidazolone, A Mutagenic Product Of Oxidation Of Guanine In Dna, Hannah Catherine J. Pollard

Electronic Theses and Dissertations

2,5-diaminoimidazolone (Iz) is an important product of a 4-electron oxidation of guanine. The present research focuses on the mechanisms of formation of Iz via pathways initiated by guanine oxidation by one-electron oxidants (OEOs) generated by X-ray radiolysis in aqueous solutions. The kinetics of formation and yields of Iz in reactions of native highly polymerized DNA with different OEOs have been compared using an HPLC-based quantitative analysis of low-molecular products generated from the reaction of DNA-bound Iz with primary amines. Mechanisms of Iz formation in DNA have been investigated including oxygen and superoxide dependence as well as the hypothesis that 8-oxo-G, …


A Novel Method For Synthesis Of Hydroxytyrosol, Emmanuel Onobun Aug 2017

A Novel Method For Synthesis Of Hydroxytyrosol, Emmanuel Onobun

Electronic Theses and Dissertations

Hydroxytyrosol, 3,4-dihydroxyphenolethanol, a naturally occurring polyphenol most common in olive tree (Olea europaea), is one of the most effective member of the polyphenols family, because of its remarkable antioxidant activity, its ability to inhibit oxidation of low density lipids (LDL), and its protection against DNA oxidative damage. Hydroxytyrosol, which is widely used in cosmetics and food supplements industries, can be purchased as an olive oil extract that contains low concentration of hydroxytyrosol besides other polyphenols. The price and low natural abundance of hydroxytyrosol make alternative synthetic sources very attractive. In this research, a novel method for the synthesis of pure …


Role Of Nanoparticles In Voltammetric Signal Enhancement Exhibited By Layer-By-Layer (Lbl) Gold Nanoparticle-Modified Screen-Printed Carbon Electrodes (Spces), Ben K. Ahiadu May 2017

Role Of Nanoparticles In Voltammetric Signal Enhancement Exhibited By Layer-By-Layer (Lbl) Gold Nanoparticle-Modified Screen-Printed Carbon Electrodes (Spces), Ben K. Ahiadu

Electronic Theses and Dissertations

Screen-printed electrodes (SPEs) have found wide use as sensing platforms due to their simple fabrication, customizability in terms of geometry and composition, and relatively low cost of production. Nanoparticles have been incorporated in or interfaced with SPEs in order to improve sensor response or provide electrocatalytic capabilities. Though nanomaterial-modified SPEs are becoming increasingly common sensing platforms, the benefits provided by nanomaterials are often determined through voltammetric studies with common redox probes, such as ferricyanide. However, recent reports have documented the ferri-/ferrocyanide redox couple to be an unreliable system for characterizing some carbon-based electrodes due to the dependence of its electrochemical …


Functionalized Silica Gel For Adsorption Of Cesium From Solution, Kenneth Marshall Seaton Iii May 2017

Functionalized Silica Gel For Adsorption Of Cesium From Solution, Kenneth Marshall Seaton Iii

Electronic Theses and Dissertations

Mesoporous silica gel containing embedded phosphotungstic acid (PTA) was synthesized by sol-gel co-condensation of tetraethyl orthosilicate with PTA in acidic media. The obtained material had high Brunauer-Emmett-Teller Theory (BET) surface area and pore volume. A characteristic band of the Keggin structure of PTA was present in its FT-IR spectrum while its X-ray diffraction patterns were absent. This proved the embedding of PTA on a sub-molecular level and not as a second phase. Acidic sites were determined by neutralization with base in aprotic solvent, followed by titration of the remaining base with an acid. The material demonstrated high adsorption capacity of …


Ab Initio And Semi-Empirical Calculations Of Cyanoligated Rhodium Dimer Complexs, Yazeed Asiri May 2017

Ab Initio And Semi-Empirical Calculations Of Cyanoligated Rhodium Dimer Complexs, Yazeed Asiri

Electronic Theses and Dissertations

Molecular modeling, using both ab initio and semi-empirical methods has been undertaken for a series of dirhodium complexes in order to improve the understanding of the nature of the chemical bonding in this class of homogeneous catalysts. These complexes, with carboxylamidate and carboxylate ligands, are extremely functional metal catalysts used in the synthesis of pharmaceuticals and agrochemicals. The X-ray crystallography shows anomalies in the bond angles that have potential impact on understanding the catalysis. To resolve these issues, minimum energy structures of several examples (e.g. Rh2(NHCOCH3)4, Rh2(NHCOCH3)4NC, Rh …