Physical Sciences and Mathematics Commons^™

Synthesis Of Chemical Models Of Hydrolase Enzymes For Intramolecular Catalysis., Cornelius Ndi Ndi

Electronic Theses and Dissertations

Most nuclease enzymes can hydrolyze phosphoester bonds (in DNA and RNA) by using metal ions cofactors that coordinate and activate water molecules in the enzymes' active sites. However, there are some hydrolase enzymes (including nucleases) that can function without the aid of metal ions. 2,6-Di(1H-imidazol-2-yl)phenol, a model compound for hydrolase enzyme, was synthesized by the reaction between ethylenediamine and dimethyl-3-carboxysalicylate, initially resulting in the formation of diimidazoline. The diimidazoline was subsequently aromatized to the diimidazole by dehydrogenation over palladium. The overall reaction yield was low; therefore, other dehydrogenation transformation reactions were tried but all failed to improve the …

Determination Of Select Metal Ions In Commercially Available Conventional And Organic Baby Foods., Neva S. Winters

Electronic Theses and Dissertations

The goal of this study is to determine whether or not there is an appreciable difference between concentrations of various metal ions present in conventionally grown and processed and organically grown and processed baby foods. Two prominent, commercially available brands were chosen to undergo comparative studies between both their own conventional and organic varieties of second stage green beans and carrots. Samples were tested for cadmium, calcium, iron, lead, nickel, and zinc. Two containers of each variety of baby food were sampled in triplicate, with purchases of foods being made in separate areas to ensure that each set came from …

Fabrication Of Chemically Modified Nanometer-Sized Gold Electrodes And Their Application In Electrocatalysis At Pt Nanoparticles., Jude Lakbub

Electronic Theses and Dissertations

Hydrogen evolution via proton reduction occurs at a high rate at the surface of Pt than at Au electrodes. Using cyclic voltammetry, chemically modified nanometer-sized Au electrodes, prepared by the Laser-Assisted Puller Method, were employed to examine current amplification by electrocalysis at Pt nanoparticles adsorbed on the modified Au electrode surfaces. The electrodes were modified with Self-Assembled Monolayers (SAMs) of cysteamine and soaked in Pt colloid solutions overnight. Monitoring the decrements of the characteristic steady-state catalytic current for proton reduction indicated that aggregates of Pt nanoparticles are adsorbed on the cysteamine monolayers and desorb from them particle by particle. The …

Mesoporous Functionalized Materials For Post-Combustion Carbon Dioxide Capture., Kolade Omoniyi Ojo

Electronic Theses and Dissertations

Novel highly functionalized hybrid organic-inorganic materials were synthesized by polycondensation of bis[3-(trimethoxysilyl)propyl]amine in presence of cationic and anionic surfactants. Reaction media strongly affected gelation time. Thus, in basic media gelation occurred immediately while acid increased gelation time. Material structures were studied by IR spectroscopy, porosimetry, XRD, and SAXS methods. In spite of the absence of an inorganic linker, obtained bridged silsesquioxanes had mesoporous structure. A material prepared in the presence of dodecylamine as a template had higher surface area and narrow pore size distribution while the use of sodium dodecylbenzene sulfate resulted in formation of mesopores with wide size ranges. …

Modified Organoclay Containing Chelating Ligand For Adsorption Of Heavy Metals In Solution., Mary Akuyea Addy

Electronic Theses and Dissertations

Presence of a chelating ligand in the clay structure significantly improves its ability to immobilize heavy metals from contaminated sludge or wastewater. Two-step modification procedure comprising sequential pillaring and grafting of chelating agent to the modified clay is involved.

Montmorillonite and kaolin were chosen as typical examples of expandable and non-expandable clays, correspondingly. Modifications with silica and ferric oxide were targeted on development of mesoporous structure. Laboratory tests of the organoclay efficiency for purification of wastewater were conducted with the most promising sample, i.e. organoclay with the highest specific loading of chelating agent. Experiments were conducted with model wastewater containing …

Synthesis Of Resveratrol Ester Derivatives Using Selective Enzymatic Hydrolysis., Marian Osei-Mensah

Electronic Theses and Dissertations

Resveratrol, a naturally derived stilbene, is an interesting compound mostly talked about recently because for its anti-cancer properties. Unfortunately it has some shortcomings due to its low bioavailability and low solubility in water. For this reason, my research is to overcome resveratrol's drawbacks by improving its bioavailability and hydrophilicity. My research is focused on syntheses of novel derivatives of resveratrol such as 3, 5-di-O-isobutyroyl resveratrol and 3, 5-di-O-hexanoyl resveratrol using lipase catalyzed hydrolysis. Therefore, the tri-acylated resveratrols 3, 5, 4'-tri-O-isobutyroyl resveratrol and 3, 5,4'-tri-O-hexanoyl resveratrol were first synthesized.

3,5,4'-tri-O-isobutyroyl resveratrol and 3,5,4'-tri-O-hexanoyl resveratrol were then hydrolyzed using lipase (C. …

Synthesis Of N-(Substituted Phenyl) Acetamides., Landon Zink

Undergraduate Honors Theses

No abstract.

A Study Of The Effects Of Titanium Dioxide Nanoparticles On The Fluorescent Intensity Of Fluorescent Compounds In The Presence Of Known Quenchers., Vivian Dzigbodi Koka

Electronic Theses and Dissertations

Titanium Dioxide is a naturally occurring oxide of titanium. It has a wide range of uses in commercial products for providing whiteness and opacity. It has photocatalytic properties and can also be used to produce electricity in its nanoparticles form. This research is focused on investigating the effect of titanium dioxide nanoparticles in analysis of compounds using luminescence-based techniques. Quenching, which is one of the basic problems of fluorescent measurements, was studied in the presence of molecular oxygen and methyl iodide. The rutile phase of titanium dioxide nanoparticles was synthesized by the acid hydrolysis of titanium isobutoxide at low temperatures …

Using Electrochemical Method To Study The Interaction Between Dna And A Compound Known To Have Anticancer Property., Alexander Kamasah

Electronic Theses and Dissertations

The interaction of 4-(1'-[8'-(1''-pyrenyl)naphthyl])-2,6-diaminopyridine bis-glycamide bishydrocholride known to have anticancer properties with deoxyribonucleic acid (DNA) had been studied on a modified gold electrode by self-assembled monolayer using cyclic voltammetry. K₄Fe (CN)₆ was used as a probe to obtain electrochemical information on the electrode surface.

A bare gold (Au) electrode was modified with cysteamine and our results showed no change in the limiting steady state current as compared to the bare Au electrode. There was a reduction in the steady state current after the modification of the gold electrode with DNA. Immobilization of the DNA modified gold electrode …

Survey Of Flavonoids And Their Distribution In Different Kinds Of Onions Using High Performance Liquid Chromatography And Gas Chromatography Mass Spectrometry., Archana Racharla

Electronic Theses and Dissertations

This research is done to determine the distribution of flavonoids in diverse varieties of onions (commercial and wild onions). Reflux extraction method was done on dried onions and the abstracts were analyzed subsequently by high performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GCMS). Statistical calculations were done to see if there are significant differences in the varieties of onions studied from the chromatographic profiles obtained. The chromatograms obtained were patterned using visual observations, scatter plot study, correlation co-efficient, and ANOVA to evaluate the significant difference of the distribution of flavonoids in varieties of onions. The organic white onions seem …

Quenching Of The Fluorescence Of Tris (2 2-Bipyridine) Ruthenium(Ii) [Ru(Bipy)3]2+ By A Dimeric Copper(Ii) Complex., Kevin E. Cummins

Electronic Theses and Dissertations

The quenching of the [Ru(bipy)₃]²⁺ by Cu₂L²⁺ was studied and the data were plotted with the Stern-Volmer equation. The plot showed a break and was divided into 2 regions, <0.5 and >0.5 Cu₂L²⁺: [Ru(bipy)₃]²⁺ molar ratio. Quenching above the 0.5 Cu₂L²⁺: [Ru(bipy)₃]²⁺ molar ratio was slower (330 x 10^-6 M^-1s^-1) than the quenching rate reaction below 0.5 ratio (387 x 10^-6 M^-1s^-1).

With Cu₂L²⁺ being a dimeric complex the …

Electrochemical Studies Of The Interaction Between Dna And A Compound Having Anticancer Properties., Antibe Pouliwe

Electronic Theses and Dissertations

Electrochemical method has been used to study the interaction between DNA and the compound N-(3',6'-dihydroxy-3-oxospiro[isobenzofuran-1(3H),9'-[9H]xanthen]-5-yl)-N'-(2-imidazoyl)urea having anticancer properties. A DNA modified nanometer-sized gold electrode was prepared by surface modification of a bare gold electrode using cysteamine. These electrodes have been characterized using electrochemical techniques and were used to study the interaction between DNA and the compound. Our results showed an increase in the adsorption peak current and a negative shift of E_1/2 in the oxidation of ferrocyanide on cysteamine and DNA modified electrodes. For the interaction between the DNA and the compound having anticancer properties, a decrease in peak …

Electrochemical Studies Of Reactions In Small Volumes Less Than 1 Femto Litres., Isaac Agyekum

Electronic Theses and Dissertations

Electrochemical methods have been used to study electron transfer reactions at the interface between an aqueous phase of less than 1 femto liters in volume and a bulk organic phase. The small aqueous phase is formed at the end of a slightly recessed platinum electrode. When a negative potential is applied between the Pt electrode and the aqueous phase, Ru(NH₃)₆³⁺ in the aqueous phase could be reduced to Ru(NH₃)₆²⁺. Because the volume of the aqueous phase is very small, the electrochemically formed Ru(NH₃)₆²⁺ could instantly reach the …

Synthesis Of A Resveratrol Glycinate Derivative., Shelley Marie Van Cleve

Electronic Theses and Dissertations

Recently, the compound resveratrol has had media attention as an anti carcinogen. However, the bioavailability of resveratrol is low in the human system due to its hydrophobic nature. Therefore, it must be administered in high dosages to be effective. A plethora of derivatives have been synthesized that have the potential of resveratrol but sadly share low bioavailability. The first effort of this research was an attempt to produce a more hydrophilic ester of resveratrol. Failing this, the final product was synthesized using a glycine derivative to produce 4-[(1E)-2-(3,5-diacetyloxyphenyl)ethenyl]phenyl N-[(1,1-dimethylethoxy)carbonyl]-glycinate.

Determination Of Selected Heavy Metals In Some Creeks In A Tennessee City., Ann Ejimole Item

Electronic Theses and Dissertations

Concentrations of Ni, Cu, Zn, Fe, Cd, and Pb were determined in six different creeks within a city in Tennessee using Atomic Absorption Spectrophotometer. Mean concentrations of Ni, Cu, Zn, Cd, Pb, and Fe in the sites examined reveal that they exceed the USEPA recommended limits. High concentrations of Cu (0.130 mg/L), Zn (13.7 mg/L), Ni (0.267 mg/L), and Cd (0.010 mg/L) were observed in site B and Fe (3.01 mg/L) in site E relative to other sites. The concentration of Pb (0.795 mg/l) was higher in site A. Higher concentrations of Cu, Zn, and Fe were detected in samples …