Chemistry Commons^™

Determining The Lon-Exchange Mechanism Of Strontium Into A Niobium Doped Titanosilicate, Samantha Jane Kramer

Masters Theses & Specialist Projects

A 25% niobium substituted sitinakite was exchanged with strontium as time resolved X-ray diffraction data was collected. The structural modeling of this data by Rietveld method1 has lead to the determination of the atomic positions of the ions and unit cell parameters as strontium occupancy increases.

The starting material of the exchange experiment is the protonated phase, H2Nb0.67Ti1.33SiO7·1.9 H2O, with space group P42/mcm2,3. Once strontium (Sr2+) enters the unit cell, extra-framework H2O molecules shift to provide the necessary hydration coordination. These new positions of H2O result in a lowering of symmetry to the P-42m space group, and it is thought …

The Pt2 (1,0) Band Of System Vi In The Near Infrared By Intracavity Laser Absorption Spectroscopy, Leah O'Brien, James O'Brien

Chemistry & Biochemistry Faculty Works

Intracavity laser absorption spectroscopy has been used to record rotationally resolved electronic spectra of Pt2 in the near infrared. The metal dimers were created using a 50 mm-long, platinum-lined hollow cathode plasma discharge. The observed transition at 12 937 cm−1 is identified as the (1,0) band of System VI, with state symmetries Ω = 0 – X Ω = 0.

Nonamphiphilic Modification Of The Self-Assembly Behavior Of Surfactants And The Potential For Bolaamphiphile-Based Vesicle Formation In The Presence Of 5’Disodium Cromoglycate, Nemal S. Gobalasingham

Renée Crown University Honors Thesis Projects - All

Emulsion systems stabilized by surfactants have historically been driven by the separation of hydrophobic oils from water, essentially creating surfactant micelles. As surfactant molecules aggregate around the oil, they self-assemble in such a way that the hydrophobic chains of the surfactants face inward toward the oil while the hydrophilic, or water-loving, “head” of the surfactant face outward toward the water medium. The emergence of water-in-water emulsions consisting of droplets of a water-solvated biocompatible liquid crystals, disodium cromoglycate (5’DSCG), with polymers has unlocked the potential for modifying the self-assembly behavior of surfactants. We report here on the capacity of 5’DSCG to …

Approach To Arsenic And Selenium Removal From Fly Ash By Oxalate And Estimation Of Calcium Effects On Both Elements, Ying Wen

Masters Theses & Specialist Projects

An approach to arsenic and selenium removal from fly ash is studied. This research includes a comparison of the leaching ability of ammonium oxalate, ammonium citrate, ammonium nitrate and EDTA to extract arsenic and selenium; use of common agricultural waste as a source of oxalate anion to remove arsenic and selenium from fly ash and estimation of additional calcium effects on arsenic and selenium leaching behaviors.
This research shows that extraction strength order is EDTA > ammonium oxalate > ammonium citrate > ammonium nitrate > water, achieving arsenic extraction efficiencies of 94.18%, 84.17%, 4.50%, 2.89% and 0.18%, respectively; achieving selenium extraction efficiencies of 96.14%, …

An Assessment Of Stable Hydrogen-Isotope Analysis Methods To Assign Geographic Origin To Migratory Red-Tailed Hawks (Buteo Jamaicensis), Carla Marie Ahlschwede

Department of Environmental Studies: Undergraduate Student Theses

Stable-hydrogen isotopes are becoming an increasingly popular method of studying migratory birds, though sample preparation methods may affect results.  In this study I examined feathers from red-tailed hawks (Buteo jamaicensis) to determine the relationship between measure of δD due to inter-feather variation or drying methods, assessed the accuracy of results by using two birds of known-origin and estimated possible natal origins of migratory red-tailed hawks.  Two feathers per individual were taken from 81 wild hawks caught at Hitchcock Nature Center near Crescent IA and from 2 rescued red-tailed hawks, Raptor Recovery Nebraska near Eagle, NE. 119 of the …

Slow Magnetic Relaxation And Electron Delocalization In An S = 9/2 Iron(Ii/Iii) Complex With Two Crystallographically Inequivalent Iron Sites, Susanta Hazra, Sujit Sasmal, Michel Fleck, Fernande Grandjean, Moulay T. Sougrati, Meenakshi Ghosh, T. David Harris, Pierre Bonville, Gary J. Long, Sasankasekhar Mohanta

Chemistry Faculty Research & Creative Works

The magnetic, electronic, and Mössbauer spectral properties of Fe ₂L(µ-OAc)₂ClO₄, 1, where L is the dianion of the tetraimino-diphenolate macrocyclic ligand, H₂L, indicate that 1 is a class III mixed valence iron(II/III) complex with an electron that is fully delocalized between two crystallographically inequivalent iron sites to yield a [Fe₂]^V cationic configuration with a S_t 9/2 ground state. Fits of the dc magnetic susceptibility between 2 and 300K and of the isofield variable-temperature magnetization of 1 yield an isotropic magnetic exchange parameter, J, of -32(2) cm^-1 for an …

Oxidative Derivatization Of Folic Acid Monitored By Capillary Electrophoresis With Uv Absorbance And Fluorescence Detection, Jeffrey P. Cunniff

Honors Capstones

No abstract provided.

Combining Bioinformatics And Chemical Biological Approaches To The Study Of Signaling Pathways In Parasitic Nematodes, William R. De Martini

Theses, Dissertations and Culminating Projects

Lymphatic filariasis (elephantitis) is a disfiguring disease caused by thread-like nematodes. This disease affects the lives of over 120 million people and over one billion people are at risk for infection in endemic regions. Drugs used to treat this disease suffer from toxicity and emerging resistance and new therapies need to be identified. Our laboratory has been studying the filarial parasite, Brugia malayi (B. malayi), one of the causative agents of this disease. The laboratory is focused on the study of critical protein kinase signaling pathways, necessary for parasite protective anti-oxidative responses, as potential therapeutic targets. We have previously determined, …

The Applications Of Graphene And Its Derivatives For Heavy Metal Removal, Clemonne John Madarang

Theses, Dissertations and Culminating Projects

Heavy metal pollution is very prevalent in our environment. The entire removal of heavy metal and organic contaminants in natural water resources will not only affect the environment itself, but also can block the toxic contaminant transfers in food chains. Currently, there are many studies being done to remove these heavy metal ions from our water, such as reduction reactions, chemical precipitation, reverse osmosis and electrolytic recovery. One of the promising techniques is adsorption. The focus of this research is using graphene and its derivatives, such as silylated graphene oxide (GO), to adsorb heavy metals, specifically, lead. This research describes …

Investigation Of Charge Recombination In Escherichia Coli Photolyase And Vibrio Cholera Cryptochrome Dash, Agnieszka Zieba

Theses, Dissertations and Culminating Projects

Proton-coupled electron-transfer (PCET) is a mechanism of great importance in protein electron transfer and enzyme catalysis, and the involvement of aromatic amino acids in this process is of much interest. The DNA repair enzyme photolyase provides a natural system that allows for the study of PCET using a neutral radical tryptophan (Trp‘). In Escherichia coli photolyase, photoreduction of the flavin adenine dinucleotide (FAD) cofactor in its neutral radical semiquinone form (FADH') results in the formation of FADH and Trp . Charge recombination between these two intermediates requires O A/T # the uptake of a proton by ~ Trp . The …

Cu(I) Wires: Structural Polymorphism And Photoluminescence, Cristina Dubceac

Chemistry

Metal wires are a linear arrangement of metal centers that conduct electrical current. Linear polynuclear metal clusters are of great importance for the design of metal-rich nanomaterials and the development of theories describing metal-metal bonds. Theoretical work on metal strings is valuable in understanding their properties and discovering their potential applications as molecular wires. Linear metal atom chains can be ligand supported or unsupported. The anions of polypyridylamines have been used extensively to support linear metal chains. However, due to challenges involving the synthesis of these ligands, the longest metal chain reported contains nine metal atoms. Examples of unsupported extended …

Forensic Dna Analysis And The Validation Of Applied Biosystems 3730 Dna Analyzer And Genemapperid-X Software For Str Analysis, Carolyn Frantz

Chemistry

No abstract provided.

Incorporation Of Novel Diphosphines Into Polymer Structure For Light Absorption And Emission Applications, Thora Maltais

All Theses

In today's society, there is a constant need for the development and production of new and improved technology, especially in the development of light emitting diodes for screens in electronic devices, and photovoltaic cells as sources for alternative energy. New insights for the development of such technology can be elucidated through the incorporation of chromophoric diphosphines into phosphonium and platinum(II) polymer frameworks. From diphosphine incorporation, it will be shown that polymer properties can be enhanced for such applications by invoking phosphorescence, and providing a modular platform for generating multilayer polymer films that provide intriguing energy transfer capabilities in the visible …

Germline Cyst Formation And Development In Zebrafish, Tess Cherlin

Renée Crown University Honors Thesis Projects - All

In developing pre-natal mice, germline cysts are clusters or packages of cells consisting of individual oocytes. They are formed after the primordial germ cells move to the ovary during embryogenesis. The primordial germ cells divide, but do not completely separate. The cells within the cysts are linked by intercellular bridges, which end up breaking down leading to the formation of primordial follicles. The primordial follicles are oocytes surrounded by somatic cells called granulosa cells. Only one third of the original oocytes survive cyst breakdown and become the eggs that will be used by the mouse for her reproduction. This developmental …

Exploring The Potential For B12-Based Oral Vaccine Delivery; Cubilin Mediated Uptake Of B12-Conjugate Systems Greater Than 160 Kda, Teresa Soldner

Renée Crown University Honors Thesis Projects - All

This project aimed to create a novel oral tetanus vaccine by exploiting the B₁₂ uptake pathway. While many linkers were attempted, the only successful complex was created using CDT coupling. After synthesis, purification (with some difficulty), and characterization, tests were done in vitro and in vivo. These supported the conclusion that while the complex was being successfully taken up by the cell, the complex was not created a strong enough immune response for a positive titer. On a second note, simply the uptake of B₁₂-TT is remarkable because it is the largest molecule that has been …

Adsorbents With Chemically Bonded Saccharide Surfaces: Synthesis And Application For Stereoisomer Separation And The Synthesis Of Chiral Porous Silicas Using Templates Chiral Surfactant, Edwin Vega

Seton Hall University Dissertations and Theses (ETDs)

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Probing Ground-State Single-Electron Self-Exchange Across A Molecule−Metal Interface, Yuanmin Wang, Papatya C. Sevinc, Yufan He, H. Peter Lu

Chemistry Faculty Publications

We have probed single-molecule redox reaction dynamics of hemin (chloride) adsorbed on Ag nanoparticle surfaces by single-molecule surface-enhanced Raman spectroscopy (SMSERS) combined with spectroelectrochemistry. Redox reaction at the molecule/Ag interface is identified and probed by the prominent fluctuations of the Raman frequency of a specific vibrational mode, nu(4), which is a typical marker of the redox state of the iron center in a hemin molecule. On the basis of the autocorrelation and cross-correlation analysis of the single-molecule Raman spectral trajectories and the control measurements of single-molecule spectroelectochemistry and electrochemical STM, we suggest that the single-molecule redox reaction dynamics at the …

Protein-Lipid Interactions: Influence Of Anchoring Groups And Buried Arginine On The Properties Of Membrane-Spanning Peptides, Vitaly V. Vostrikov

Graduate Theses and Dissertations

Designed transmembrane peptides were employed for investigations of protein-lipid interactions by means of oriented solid-state deuterium NMR spectroscopy using isotope-enriched alanine residues. Using the model GWALP23 sequence (GGALW(LA)6LWLAGA) as a host peptide having single interfacial tryptophan anchor residues, the effects of different guest mutations were explored. Replacements of glycine residues 2 and 22 to positively charged lysine or arginine on both termini had little influence on the peptide average orientation. Conversely, glycine to tryptophan substitutions had profound effects, manifested in the increased dynamics and altered tilt direction of the peptide. While the charged residues at the peptide termini did not …

Photopolymerized Thiol-Ene Networks For Gas Barrier And Membrane Applications, Luke Kwisnek

Dissertations

Gas transport and free volume properties of photopolymerized thiol-ene networks for various applications are reported. For basic, commercially-available thiol-ene formulations, oxygen permeation was strictly dependent on the difference between T_test (room temperature for this work) and network T_g. Networks with T_g near T_test demonstrated the lowest values of permeability, diffusivity, and solubility. A robust, high-barrier network was selected for further modification. New networks with embedded functionality were formed using a two-step approach. Thio-Michael addition of a tetrathiol to monofunctional acrylates formed new functional thiol monomers. These functional thiols were combined with an isocyanurate-based triene and …

Mechanisms Of Non-Enzymatic Peptide Bond Formation: Thioester And Transamidation Routes, Danielle Amie Landry

Master's Theses

The reaction mechanisms employed during non-ribosomal peptide (amide) synthesis in the non-ribosomal modular enzyme complex and in the enzyme glutaminyl cyclase were also used for spontaneous peptide (amide) synthesis in a buffered, abiotic solution. Analytical analyses revealed that spontaneous peptide (amide) bond formation occurred under mild prebiotic conditions during both the thioester-based production of phenylalanine peptides and peptidyl thioesters, and the spontaneous cyclization of glutamine t-butyl ester (Gln-tbe) into pyroglutamic acid t-butyl ester. Internal standard-based quantitative MS determined that 4.9 x 10-5 sec-1 was the rate constant for spontaneous Gln-tbe cyclization in imidazole buffer, pH 7, at 50°C, and that …

Synthetic Dosage Lethality Screen With Actin Cytoskeleton In Yeast, Jessica Cho

Renée Crown University Honors Thesis Projects - All

The actin cytoskeleton is a vitally important organizing structure found in the cytoplasm of our cells. It contributes to essential cell functions from growth and cell division, development, signal transduction, adaptation, to gene expression. Interest in how regulation of the actin cytoskeleton---due to actin cytoskeleton's importance to cell function-may contribute to diverse human disease states such as the rampant cell division and metastasis that occurs in cancerous tissues. It has been further elucidated that many human genetic disorders are the result of complex haploinsufficiencies (CHI) and/or altered gene dosages at multiple loci. By reviewing a large number of potential Synthetic …

Quantum Dot Biofunctionalization, Nathaniel J. Miska

Renée Crown University Honors Thesis Projects - All

We have shown the efficacy of Quantum Dots (qdots), nano-scale fluorescent particles made of semi-conductive material, as versatile biologically functional research tools. This functionality depends upon a series of chemical transformations that produce stable, aqueous, biomolecule-bound qdots with high quantum yield. We utilize the metal binding and chelating properties of the amino acid histidine to displace hydrophobic surface ligands and to phase-transfer qdots from organic to aqueous media. The intermediate binding strength of histidine to qdot surface facilitates its exchange with a variety of strongly binding thiolated biomolecules. Ligand profiles are subsequently characterized via FTIR, NMR, and gel electrophoresis. Negatively-charged …

Characterization Of Novel Macrocyclic Polyether Modified Pseudostationary Phases For Use In Micellar Electrokinetic Chromatography And Development Of A Chemiluminescence Presumptive Assay For Peroxide-Based Explosives, Raychelle Burks

Department of Chemistry: Dissertations, Theses, and Student Research

This work describes the first use and characterization of macrocyclic polyether (MP) modified sodium dodecyl sulfate (SDS) pseudostationary phases (PSPs) for use in micellar electrokinetic chromatography (MEKC), as well as the development of a presumptive chemiluminescence assay for peroxide-based explosives. In MEKC separation and detection, resolution is optimized by using various PSPs or by altering the properties of a single PSP using different class I or II modifiers. Class I modifiers target the PSP through direct interaction with micelles, while class II organic modifiers operate by altering the BGE. The of MPs 18-crown-6, 15-crown-5, and 12-crown-4 were used to modify …

Purification Of Lysine Decarboxylase: A Model System For Plp Enzyme Inhibitor Development And Study, Leah C. Zohner

Department of Chemistry: Dissertations, Theses, and Student Research

Pyridoxal phosphate (PLP) dependent enzymes have the ability to manipulate amino acid substrates, serving variously as (i) racemases, transaminases, and beta- or gamma eliminases (all involving Cα-H bond cleavage); (ii) decarboxylases (Cα-CO2- bond cleavage), or (iii) retroaldolases (Cα-Cβ bond cleavage). Dunathan posited that stereoelectronics govern the key C-X bond cleavage step across the class of PLP enzymes; namely by aligning the scissile bond of the substrate with the extended pi system of the substrate-PLP imine that bond is weakened. A mechanistic understanding of electron flow in this enzymatic class has motivated many groups, including the Berkowitz group, to develop mechanism-based …

Extraction Chromatographic Studies Of Rutherfordium And Dubnium Homologs, Megan E. Bennett

UNLV Theses, Dissertations, Professional Papers, and Capstones

Studying the chemistry of transactinide elements does not only allow for these elements to be properly placed in the Periodic Table, but it also permits for the extrapolation of the electronic structure based upon the position of the element in the Periodic Table. In addition it enable for the assessment of the role that relativistic effects play in the chemical behavior of the heaviest elements. An improved understanding of the role of relativistic effects in chemistry of the heaviest elements allows for a better understanding of the fundamentals principles that govern the Periodic Table. In order to investigate the chemistry …

Bismuth Nitrate-Induced Novel Nitration Of Eugenol And Estradiol: An Exploratory Study, Luis Canales

Theses and Dissertations - UTB/UTPA

Molecules originating in nature have held an important place in chemistry and in society. Many of the important useful compounds of all time were first discovered in nature. Eugenol, a multi-functionalized biologically active constituent, is present in high quantity in natural clove. Eugenol is an important herb due to its medicinal activities; therefore, research on this molecule is necessary. Nitration of Eugenol was performed through various metal nitrates and solid surface combinations. Estrogens are contributors of the development of many secondary sex characteristics in females; they play various important roles in the nervous system. Direct nitration of estradiol has been …

Synthesis And Characterization Of 4,4-Prime-Distyrylbiphenyl And Its Applications In Organic Field Effect Transistors, Nestor A. Santos Jr.

Theses and Dissertations - UTB/UTPA

4,4’-distyrylbiphenyl (DSBP), an ambipolar small molecule with electroluminescent properties, was synthesized following two synthetic protocols. Accordingly, biphenyl was bromomethylated using a mixture of paraformaldehyde and hydrogen bromide in 20% to 60% isolated yields. Bromomethylated biphenyl was then reacted with triphenyl phosphine, or with triethyl phosphate to yield the corresponding triphenyl phosphonium bromide or triethyl phosphonate, respectively. DSBP was synthesized by reaction of the triphenyl phosphonium bromide or triethyl phosphonate with freshly distilled benzaldehyde according to the Wittig, or Horner-Wadsworth-Emmons protocols. DSBP from the Wittig reaction resulted in a mixture of cis-trans isomers, while the product from the Horner-Wadsworth-Emmons reaction yielded …

Biocompatibility Of Electrospun Polymer Nanofibers (Epns) With Nih 3t3 Cell Line And Interaction Of Quercetin With Different Flavonoids: Induction Of Phase Ii Enzymes In Vitro Cancer Cell Lines, Brenda S. Benavides

Theses and Dissertations - UTB/UTPA

Part I: In this study Electrospun nanofibers, Elasthane™ 55D, Elasthane™ 75D, Biospan®, Hydrothane™ and Lycra® were evaluated for their biocompatibility to be artificial tissue substitutes using NIH-3T3 fibroblast cells. A colorimetric based MTT dye reduction assay demonstrated that EPNs did not stop cell growth in vitro. Additionally, fluorescence confocal microscope images verified that cell adhesion occurred in the nanofibers, and cell growth on the EPNs over two weeks period was confirmed by DNA quantification.

Part II: This section of the thesis is focused on evaluation of chemopreventive properties of various phytochemicals by induction of Phase II enzymes. The interaction of …

Modification And Evaluation Of Fuel Cell Membranes, Amol Prataprao Nalawade

Dissertations

The primary goals of this study were modification of existing Nafion^® membranes and characterization of newly developed hydrocarbon-based membranes for high temperature fuel cell applications. Various Nafion^®/silicate nanocomposites were formulated via in situ sol-gel reactions for tetraethylorthosilicate. Different silicate composition profiles generated across membrane cross-sections were investigated by EDAX/ESEM. Composite water uptake, proton conductivity and fuel cell performance were comparable to that of unmodified Nafion^®. Tafel analysis showed better electrode kinetics for composites having more silicate in the middle and less or no silicate at electrolyte-electrode interfaces. All composites showed reduced fuel cross-over and superior …

Sensitive Detection Of High Explosives Using Electrogenerated Chemiluminescence, Suman Parajuli

Dissertations

The core of this dissertation lies in the search of analytical tools which can be used to detect and quantify the high explosives confiscated from suspects in transportation hubs and from soil and water bodies where these explosives pose a greater threat to public health and safety. High explosives, namely, hexamethylene triperoxide diamine (HMTD), triacetone triperoxide (TATP), trinitrotoluene (TNT), and pentaerythritol tetranitrate (PETN), were detected and quantified by electrochemical methods such as electrogenerated chemiluminescence (ECL) and cyclic voltammetry (CV).

Sensitive detection and quantification of HMTD, one commonly used explosive by terrorists, was presented first in this dissertation on the basis …