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Nanomaterial Composites For The Detection Of Nerve Gas Analogs, Yogesh Datar

Masters Theses

The basis of the research work described here is the use of nanocomposite materials built by bottom-up approach for the selective detection of nerve gas analogs. Nanocomposites materials constructed by using nanoparticle-monomer-receptor (NMR) concept have been utilized to detect nerve gas analogs DCP and DMMP. Synthetic approach used in the construction of nanosensors involved use of robust platforms such as silica nanoparticles and fluorescent quantum dots. Highly conjugated receptor molecules were synthesized by using stilbeneoid compounds. A complete opto-nanosensor was developed by anchoring highly conjugated receptor molecules onto the silica nanoparticles as well as onto the quantum dots. The opto-nanosensors …

Synthesis And Characterization Of Ruthenium Bipyridyl Complexes For Detecting Nerve Gas Agents And Explosives, Arambe Gedara Aruna Weerasinghe

Masters Theses

Five novel 2,2 '-bis bi pyridine Ru(II) complexes have been synthesized and characterized using ¹H NMR, ¹³C NMR, ¹H-¹H-COSY, elemental analysis, fast atom bombardment or electrospray mass spectra and electronic absorption spectroscopy. Binding of Ru (11) complexes with nerve gas analogos such as diethyl chlorophosphate (DCP), dimethyl methyl phosphonate (DMMP) and hydrolyzed product (HCl) has been investigated by electronic absorption, fluorescence, and lifetime studies. Compound 1 showed a quenching in ³MLCT emission after an initial increase in intensity upon the addition of DCP with a bathochromic shift of 25 nm. Compound 2 exhibit a …

Fundamental Investigation Of Vesicle Bilayer Membrane Dynamics, Wilson Okumu

Masters Theses

We studied the bilayer of vesicles from dimyristolyphosphatidylcholine (DMPC), using nitrobenzoxadiazole (NBD) probes, attached to the head (NBD-PE) and the tail (NBD-PC) of phospholipid derivatives. We characterized the bilayer as it underwent reversible transition from the gel to the fluid through a phase transition range. The main phase transition was characterized by steady state and timeresolved fluorescence anisotropy, fluorescence intensity decrement and kinetics of dithionite reduction. We also studied DMPC with dihydrocholesterol. Differences between the surface and interior regions of the bilayer region were obtained. The activation barrier was enthalpic in the gel, entropic in the fluid phase and anomalous …

Design Of Multi-Electron Transfer Catalysts For The Reduction Of Trichloroethylene, Christopher Gerard Eman Ciptadjaya

Masters Theses

For decades, organohalide (RX) compounds have been heavily used in the chemical and pharmaceutical industries and in agriculture as pesticides. Improper disposal of organohalides has resulted in their presence in the environment as pollutants, and they have therefore presented serious environmental and toxicological concerns. These organohalides have been associated with various health and environmental problems. Therefore, effective methods for their remediation are required. We have developed a multi-electron transfer (MET) catalyst consisting of flavin mononucleotide anchored to nanocrystalline mesoporous titanium dioxide (TiO₂) thin films, and examined its reactivity toward the organohalide pollutant trichloroethylene (TCE). Various environmental factors were …

Nanosensors For The Detection Of Nerve Agents And Explosives, Deepak Kumar Thimmaraju

Masters Theses

The central hypothesis of this research was development of a novel nanosensor for the detection of nerve agents and explosives. The nanosensor assembly comprises a bottom up approach with nanoparticle (N), monomer (M), nanomolecule (N) and a receptor (R) as moieties of a NMNR assembly. My research was focused on evaluating receptors for their efficiency towards the target analytes such as nerve agents and explosives. Pi electron rich receptor 2-Phenyl-2-Propanol and its fluorinated analog 1,1,1,3,3,3-Hexafluoro-2-Phenyl-2-Propanol were investigated for their ability to detect nerve agents such as DCP, its analogs DMMP and HCl along with the explosives mono, di, and trinitrotoluene. …

Synthesis And Characterization Of Stilbenoids And Their Aza-Analogs As Photoluminescent Materials For The Detection Of Nerve Agent Mimics, Chun Wang

Dissertations

A novel series of stilbenoids and their aza analogs were synthesized, characterized and used as photoluminescent components in the detection of nerve agents. Their structure-property relationship was elucidated through UV-visible and fluorescence spectroscopy. The research in this thesis is driven by the hypothesis that the two-block sensor system consisting of a receptor incorporated ruthenium complex and a fluorescent signal molecule of stilbenoids, is capable of detecting chemical warfare agents. The sensor anchored onto nanoparticles and subsequently the nanoparticles were arranged through mediated self-assembly. While photo-induced electron transfer is a well-known mechanism for sensor design, the described system showed that photo-induced …

Synthesis, Study Of Self-Assembly, And Trivalent Lanthanide Metal Ion Recognition Characteristics Of Amphiphilic Acylpyrazolones And Amphiphilic Acylisoxazolones, Venkat Reddy Guduru

Dissertations

This research project focused on the separation of trivalent lanthanide metal ions by HPLC using amphiphilic acylpyrazolones and amphiphilic acylisoxazolones. The central hypothesis of our research project is that the nanoscale self-assembly nature of amphiphilic ligands (chelating lingads) can influence their metal ion recognition and separation. To test the central hypothesis, we have synthesized a family of novel amphiphilic ligands and employed them as model systems for the separation of trivalent lanthanide metal ions. Several novel intermediates such as 4-acylated. N -acylated, O -acylated pyrazolones and isoxazolones, have been efficiently synthesized and fully characterized.*

The trivalent lanthanide metal ion recognition …

Nitrogen Heterocyclic Compounds As Receptors In Nanosensors For Nerve Gas Agent Analogs, Swapna Katram

Masters Theses

The research is focused on developing nanosensors consisting of different components that are chemically linked, namely, nanoparticle, fluorescent monomer, and receptor (NMR sensors) and nanoparticle, monomer, nanomolecule, and receptor (NMNR sensors) for the sensitive and selective detection of nerve gas agents. These sensors detect the target toxins by fluorescence change which is amplified by signal transduction. Model nerve gas toxins (DCP) and (DMMP) and HCl were employed as analytes, and the nitrogen heterocyclic compounds, 5-aminoindazole and dipyrido[3,2-a:2',3'-c]phenazine (dppz) as receptors in the NMR and NNMR nanosensors. The monomers were (E)-4-(4- formylstyryl) benzoic acid (NMR sensor) and 2-mercaptosuccinic acid (NNMR sensor). …

Synthesis And Characterization Of Doped Core/Shell Quantum Dots, Elizabeth J. Sodt

Masters Theses

The central theme of the research performed is the systematic modification of the optical properties of quantum dots by the formation of a shell of another quantum dot of a different band gap energy. Core/shell quantum dots such as CdS:Mn/CdS, CdS:Mn/ZnS, and ZnS:Mn/CdS with various concentrations of dopant Mn²⁺ in the core and shell concentrations have been synthesized under mild conditions in the aqueous phase using stoichiometric amounts of the surfactant stabilizer dodecyl sulfate. These quantum dots exhibit UV-vis, emission, and electron paramagnetic resonance (EPR) spectral behavior that is dependent on the concentration of the shell and the dopant …

The Effect Of Chloramphenicol On Bb88 Murine Erythroleukemia Cells, Peter K. W. Harris

Dissertations

DNA microarrays can be used to measure genome-wide transcript levels. These measurements may be useful in understanding cellular changes induced by a chemical agent. In this study, Affymetrix microarray technology has been used to study the effects of chloramphenicol, an antibiotic that inhibits bacterial and mitochondrial protein synthesis, on the transcription profile in mammalian cells. Transcript levels in BB88 murine erythroleukemia cells treated with 50 micromolar ( mu M) chloramphenicol, a concentration shown to inhibit BB88 proliferation, are measured. Using total RNA from treated cells, biotin-labeled cRNA was prepared and hybridized to Affymetrix U74Av2 microarrays. From these hybridizations, expression levels …

The Global Hepatic Transcriptional Response Of Male Fisher Rats To Dietary Aroclor 1254 Exposure, Trisha M. Basford

Dissertations

Dietary intake is a primary route for biomagnification of environmentally persistent polychlorinated biphenyls (PCBs) within humans and animals. Aroclor 1254, a mixture of PCBs, is associated with a variety of toxic responses including alterations in blood and lipid biochemistry and tumor promotion. Measurement of the transcriptional responses to low-level dietary exposure to A1254 has not been reported to date, and is important given the persistence of PCBs, and range of effects associated with exposure. The aims of this study were to characterize changes in rat hepatic global gene expression due to sub-acute and sub-chronic dietary exposure to A1254, and to …

Stability Testing Of Mint Oils Through Gas Chromatography Analysis, Sarah Wolf

Honors Theses

In this experiment, the stability of mint oil was measured through gas chromatography analysis. Eight different oils were tested. Levels of key components of mint oil, including menthol and menthone for peppermint oil, and carvone and limonene for spearmint oil, was compared over time. Several packaging materials were immersed in oils in order to determine their effects, if any, on the composition of the oils. Additionally, oil was subjected to either 25 degree or 40 degree Celsius temperatures to determine if temperature affected the oil composition.

Bioengineering Of Protein Nanotubes And Protein Nanomaterial Composites, Thilak Kumara Mudalige

Dissertations

Flagella of Mesophilic bacteria such as E. coli are extremely ordered structures consisting of self-assemblies of flagellin 11-mers resulting in protein nanotubes of 2--3 nm inner diameter, 23 nm outer diameter, several microns in length and 5.4 nm separation between 11-mer segments. They are as a result attractive scaffolds and templates for the generation of uniform nanotubes and ordered array of nanoparticles. In this study fusion protein of bacterial flagellin (Fli C) and core thioredoxin (Trx), pFliTrx was used as peptide display on bacterial flagella. This was accomplished in the current research by introducing various peptide loops such as cysteine, …

Development Of Scanning Electrochemical Microscopy For Studying Electron Transport In Lipid Monolayers And Gold Nanoparticle Films, Violeta Stoycheva

Masters Theses

The focus of this thesis is the scanning electrochemical microscopy (SECM) investigation of the electron transport in lipid monolayers and in films of gold nanoparticles. The quality and stability of lipid monolayers were characterized by various analytical techniques such as fluorescence microscopy and spectroscopy, contact angle, and electrochemistry using a monolayer modified electrode. In the SECM measurement, the monolayer electron transport was not detected. The microscopic monolayer quality turned out to be not suitable for studying the electron transport.

The conductivity of mono layer protected gold clusters (MPCs) with different core sizes (1-3 nm diameter) were investigated using SECM. These …

Heterogeneous Formation Of Hono On Hno3 Pre-Conditioned Hydrophobic, Hydrophilic And Ionic Surfaces At Various Relative Humidities, Dustin S. Wier

Masters Theses

Nitric acid (HNO₃) is a major sink for NO_x (NO+NO₂ ) and is known to be removed from the atmosphere as a result of wet and dry deposition where it is then deposited on various surfaces in the environment. As these surfaces are photolyzed HONO is produced which affects the overlying troposphere. This study examines the amount of HONO (Nitrous Acid) produced by the photolysis of adsorbed HNO₃ as a function of changing relative humidity on hydrophobic, hydrophilic, and inorganic ionic salt surfaces. The amount of HONO produced was measured in long path cell using …

Transcriptional Regulation Of Glucose-6-Phosphate Dehydrogenase (G6pdh) By Glucose, Pramod U. Thekkat

Masters Theses

In liver, insulin and glucose regulate the expression of important genes for lipid and carbohydrate homeostasis. Studies on the effects of glucose and insulin, including effects on cell signaling, are vital since deficiencies in glucose utilization in cells and/or insulin secretion contribute to conditions like obesity and diabetes. In liver, the pentose phosphate pathway is one of the primary pathways that can utilize the excess carbohydrate. Glucose-6-phosphate dehydrogenase (G6PDH) is an important rate limiting enzyme in this pathway. Our laboratory has shown that both insulin and glucose induce the expression of G6PDH, although the mechanism by which this transcriptional regulation …

Biochemical Characterization Of Disease-Causing Mutation In N-Terminal Wilson Protein Domain Six, Patrick Ochieng

Masters Theses

Wilson protein (ATP7B) is a copper-transporting P-type ATPase that regulates copper homeostasis and secretion of copper-containing enzymes in the liver. In hepatocytes, ATP7B delivers copper to apoceruloplasmin and mediates the excretion of excess copper into bile. Mutation in the gene coding for Wilson protein leads to Wilson disease. Several mutations in Wilson protein have been identified and of particular interest, mutations affecting the N-metal binding region significantly interfere with the ability of Wilson protein to transport copper to its target in the copper-trafficking pathway. In an attempt to characterize the disease-causing mutation (G591D) in Wilson protein domain 6 (WLN6), we …

Global And Quantitative Gene Expression Analysis Of The Effects Of Drinking Water Exposure To Lead Acetate In Fisher 344 Male Rats Liver, Worlanyo Eric Gato

Dissertations

The primary objective of this research is to analyze global gene expression patterns occurring in Fisher 344 rat livers exposed to varying levels of lead and times. The hypotheses were that: (1) effects associated with Pb exposure are both dose and time dependent and (2) several genes will be over-expressed or repressed including transcripts associated with calcium signaling. Initially, the effects of Pb exposures upon morphometnc indices, liver and kidney tissue histology, Pb distribution, Pb interaction with other trace metals including Zn, Cu, Co, Fe, Ni and Ca were assessed. Results showed a significant accumulation of lead in blood, liver, …