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Determination Of The Activation Parameters Of Reaction Between [Fe(Cn6]-4 And K[Co(Hedta)No2]., Sammy Eni Eni

Electronic Theses and Dissertations

The kinetics of the oxidation of [Fe(CN)₆]^-4 by K[Co(HEDTA)NO₂] was studied in order to get the mechanism and the activation parameters of the reaction. Using a freshly-made Na₃PO₄ solution as the reaction medium with a pH of 6.00 the ionic strength was maintained at 0.10 M and the buffer molarity was 0.001 M.

The rate constant (k_obs) of the reaction between [Fe(CN)₆]^-4 and K[Co(HEDTA)NO₂] was determined at temperatures of 25.0°C, 27.5°C, 30.0°C, 35.0°, and 40.0°C. We explored this reaction by monitoring the evolution of ferricyanide, …

Modulation Of Restriction Enzyme Pvuii Activity By Metal Ion Cofactors, Charulata Bhaskaran Prasannan

Dissertations

Metal ions like Ca2+, Mn2+, Tb3+, Eu3+ etc., can bind at the active site and have varying effects on the enzymatic activity. In a crystal structure with DNA, two Ca2+ ions were bound to the active site of each PvuII monomer, and the metals share the ligands. Ca2+ ions promote DNA binding and not cleavage in many nucleases. We explored the role of Mg2+ and Ca2+ binding at the metal binding sites of PvuII to elucidate the role of each metal site. We monitored the cleavage kinetics of PvuII in presence of mixed metals. The cleavage kinetics data for Ca2+ …

Replacing Hydrogen Bonds With Coordinate Covalent Bonds In Coordination Networks, Colin Stewart Rodger

Dissertations

The overall theme of the dissertation is that metal ions such as silver(I) can replace H+ in hydrogen bonded organic frameworks. Because organic solids have been extensively studied, we can insert metal ions into the supramolecular assemblies, thus creating predictable coordination solids of varying dimensions. One example of an organic solid tested involves the organic compounds terephthalic and isophthalic acids. These dicarboxylic acids have previously been shown to self-assemble into tape-like structures via hydrogen bonding, with neighboring dicarboxylic acids located at angles of 180° and 120° respectively. By substituting the hydrogen bonds with coordination metal-ligand bonds similar assemblies are formed. …

Design And Synthesis Of Boronic Acid-Modified Nucleotides For Fluorescent Sensing And Cell Imaging, Xiaochuan Yang

Chemistry Dissertations

With the rapidly increasing interest in the field of glycomics, which is the comprehensive study of the roles carbohydrates play in a living system, urgent need for developing quick and highly selective carbohydrate sensors is growing. The boronic acid group, with its electron-deficient structure (6 valence electrons with an open shell), acts as a Lewis acid with high intrinsic affinity towards Lewis bases such as fluoride, cyanide and hydroxyl groups. Specifically, formation of a 5- or 6- membered ring between the boronic acid moiety and a1,2- or 1,3-diol in aqueous solution has been fully explored as a strategy of carbohydrate …

Progress Toward The Total Synthesis Of Lyconadin A, Yu Zhang

Theses and Dissertations

Lyconadin A is a pentacyclic Lycopodium alkaloid isolated from the club moss Lycopodium complanatum with antitumor properties. We have developed a novel 7-exo/6-exo acyl radical cascade cyclization as a method of making the bicyclo[5.4.0]undecane ring system of lyconadin A. The model products are trans-fused ring systems, while a cis-fused ring system is needed in lyconadin A. We have discovered a method to convert the trans-fused model cascade cyclization product into the desired cis isomer. Based on Donohoe's pyridone synthesis, we developed a method for the construction of 5-alkyl and 3,5-dialkyl-6-carbomethoxy-2-pyridones, the former of which …

Multidimensional Methods: Applications In Drug-Enzyme Intrinsic Clearance Determination And Comprehensive Two-Dimensional Liquid Chromatography Peak Volume Determination, Dennis Thekkudan

Theses and Dissertations

The goal of the first project was to evaluate strategies for determining the in vitro intrinsic clearance (CLint) of dextrorphan (DR) as metabolized by the UGT2B7 enzyme to obtain dextrorphan glucuronide (DR-G). A direct injection liquid chromatography-mass spectrometry (LC-MS) method was used to monitor products using the pseudo-first-order (PFO) model. Standard enzymatic incubations were also quantified using LC-MS. These data were fit utilizing both PFO and Michaelis-Menten (MM) models to determine estimates of kinetic parameters. The CLint was determined to be 0.28 (± 0.08) µL/min/mg protein for a baculovirus insect cell-expressed UGT2B7 enzyme. This is the first confirmation that dextrorphan …

Physical Adsorption Of Ethylene On Mgo(100): Effects Of Substrate Ionicity And Symmetry On Wetting, Andi Barbour

Doctoral Dissertations

The wetting behavior of ethylene adsorbed on MgO(100) was investigated from 83{ 135 K using high resolution volumetric adsorption isotherms. Layering transitions for ethylene on MgO(100) are observed below the bulk triple point at 79.2 K and 98.4 K, respectively. From these isotherms, thermodynamic quantities associated with physical adsorption are determined. It was found that the average area occupied by ethylene on MgO(100) is around 22.6 squared angstroms per molecule. Using the two dimensional isothermal compressibility, the location of two potential phase transitions are identified at 108.6 K and 116.5 K for the first and second layer, respectively. The potential …

Studies Of Tungsten Alkyl Alkylidyne Compounds And Iron Porphyrin Derivatives, Brenda Ann Dougan

Doctoral Dissertations

This dissertation focuses on two research projects. The first project examines the reactions of tungsten(VI) alkyl alkylidyne and bis-alkylidene complexes with phosphines and water and the studies of thermodynamics and kinetics of the reactions. These studies have been conducted in part to determine the mechanistic pathway in the formation of novel tungsten(VI) species. The second portion of this dissertation focuses on the spin density and structures of biomimetic Fe(III) porphyrin derivatives using neutron and X-ray diffraction techniques. The spin density and magnetic properties of an Fe(III) porphyrin derivative has been determined by polarized neutron diffraction.

In the first portion of …

The Design And Synthesis Of Biotinylated Tylophorine Analogues For Use As Affinity Probes In The Elucidation Of The Cellular Targets Of Dcb-3503, Samson Francis

Doctoral Dissertations

The tylophorine analogue, DCB-3503 (1-62b, NSC-716802), has been found to exhibit broad spectrum activity in vitro in the National Cancer Institute’s (NCI) panel of 60 human-derived cell lines. Recent studies involving HepG2, a human hepatocellular carcinoma cell line, and two pancreatic ductal carcinoma cell lines (PANC-1 and HPAC), have suggested that DCB-3503 (1-62b) exerts its unique growth inhibition properties by modulating nuclear factor kappa B activity as well as through the inhibition of nuclear protein synthesis. However, the physiologically relevant protein binding partner(s) of DCB-3503 (1-62b) have not been identified. Herein, the design and …

Synthesis And Characterization Of Branched Polyelectrolytes: Star-Branched Napss, Daniel W. Holley

Doctoral Dissertations

In this thesis, we examined the effect of branching on the solution characteristics of polyelectrolytes using a set of star-branched NaPSS. The polystyrene precursors to these polyelectrolytes were synthesized using anionic polymerization allowing for the production of three distinct groups of star-branched polystyrenes with varying functionality and arm length.

Following sulfonation, several methods commonly employed in the literature for evaluation of sulfonation degree we established that sulfonation was quantitative. TGA was also demonstrated to reveal important characteristics of the sample.

We used aqueous SEC coupled with a multiple angle light scattering detector to determine several molecular characteristics of the star-branched …

Design And Synthesis Of Novel Tylophorine Analogs And Their Biological Activity, Julio Gutierrez

Doctoral Dissertations

Alkaloids containing the nitrogen atom in the bridgehead position of two rings, such as indolizidine, pyrrolizidine, and quinolizidine alkaloids, have a wide and varied distribution in nature. Some of these alkaloids demonstrate a broad range of pharmacological activities and have generated substantial synthetic interest. This thesis covers the total synthesis of novel tylophorine analogs called DCB 3503, DCB 3506, DCB 3507, DCB 3508, DCB 3509, and a derivative with a biotinylated chain attached to DCB 3506 for use as a biological probe. This thesis discusses the biological activity of these compounds as well.

Reactor R&D: Synthesis And Optimization Of Metallic Nitride Fullerenes And The Introduction Of Two New Classes Of Endohedral Metallofullerenes, Metallic Nitride Azafullerenes And Oxo-Metallic Fullerenes, Curtis Earl Coumbe

Dissertations

Metallic nitride fullerenes (MNFs) were discovered in 1999. This class of endohedral fullerenes show promise in a new diverse range of useful applications. Since then, focus has shifted to the selective synthesis of these molecules with yields that would accommodate adequate sample distribution. Using the electric arc method, the traditional yield of these molecules has been very low (i.e. < 5 mg), and only a small percentage of the fullerene products (i.e. < 5%). This dissertation introduces the novel CAPTEAR (Chemically Adjusting Plasma Temperature, Energy, And Reactivity) method that allows the targeted synthesis of MNFs in high purity and yield. This method utilizes a nontraditional oxidizing method for fullerene synthesis that has not only provided optimization of MNFs, but also resulted in the discovery of two new classes of fullerenes: metallic nitride azafullerenes (MNAFs) and oxo-metallic fullerenes (OMFs). Evidence suggests that the nitrogen of the MNAF cage provides stability for the trimetallic nitride clusters, while the OMFs are the first fullerenes to encapsulate oxygen and incorporate a seven atom cluster inside a Cgo cage.

Other efforts to increase yields resulted from scaling up production of fullerenes by using larger quantities of starting materials. These larger quantities required energy (electrical current) beyond the capacity of the traditional electric arc generator. Therefore, a new electric arc generator …

Tuning Pig Liver Esterase Enantioselectivity For The Synthesis Of Unnatural Serine And Tyrosine Analogues, Dale Anthony Rosado Jr.

Dissertations

The synthesis of disubstituted and homologated unnatural amino acids and the development of a mass spectrometry based assay for enantioselectivity are presented here. Disubstituted and homologated unnatural amino acids have proven to be effective for the treatment of diseases and for use as imaging agents. Peptides that contain unnatural amino acids have also proven to be effective treatments for various disease states including cancer. The potential to evaluate such unnatural amino acids for pharmaceutical properties is limited by the available syntheses. No method currently exists that will allow for the synthesis of homochirally similar unnatural amino acids from a common …

Study Of Thermal Frontal Polymerization Utilizing Reactive And Non-Reactive Additives, Veronika Grace Viner

Dissertations

Thermal frontal polymerization is a process that involves a propagating front travelling through a monomer/initiator solution and converting monomer into polymer. The effects of different reactive and non-reactive additives on front temperature, front velocity, and pot life were studied in a thermal frontal polymerization system of multifunctional acrylates. One issue with thermal frontal polymerization of acrylate monomers is the amount of smoke and fumes produced due to high front temperatures. The effect of thermally-expandable microspheres was studied utilizing a variety of monomers. Solid additives including fillers, inert phase changer materials, and high thermal conductive fillers were investigated. The addition of …

Transcript Analysis Of The Cso Operon And Characterization Of Two Sets Of Conserved Bacterial Microcompartment Genes In The Model Organism Halothiobacillus Neapolitanus, Fei Cai

Dissertations

This study was designed to achieve better understanding of (1) how carboxysome genes are regulated and expressed to yield with precise relative ratios and (2) the in vivo roles of two sets of conserved bacterial microcompartment genes, namely the three csoSl and two csoS4 genes of H. neapolitanus, in the biogenesis and function of the carboxysome. For the first goal, a detailed transcriptional profile of carboxysomal genes in H. neapolitanus was established using absolute quantification real-time RT-PCR and transcript ends analysis. This transcriptional profile revealed that a single promoter, denoted cso promoter, was located upstream from the clustered carboxysomal genes. …

Computational Exploration Of The Interaction Of Molecular Hydrogen With An Anionic Hydrogen Atom, Patrick Karl Moehlen

Doctoral Dissertations

The focus of this dissertation is to facilitate the computation of the infrared absorption line shape of solid para-hydrogen with an anionic hydrogen atom dopant. For this, we compute the complete potential energy surface for the interaction of H¯ with H². The coupled cluster with singles, doubles, and perturbative treatment of triple excitations method was used with augmented correlationconsistent polarized valence triple-zeta atom-centered basis sets and a set of bonding functions.

The focus then turns to describing the rovibrational Hamiltonian of the system with the coupledchannel method. We find bound and quasi-bound stationary states of the system for …

Manganese Oxide Mineral Phases Produced At Room Temperature Under Acidic Conditions Investigated With Xrd, Tem, Sem, Eds, And Bet, Nancy R. Birkner

UNLV Theses, Dissertations, Professional Papers, and Capstones

This thesis concerns characterization of synthetic manganese oxides belonging to mineral phases known as Birnessite and Cryptomelane. Presented here are the results of an experiment designed to examine the influence of sodium, potassium, chloride, and sulfate ions on the reduction of potassium permanganate under acidic conditions at room temperature to produce Birnessite and Cryptomelane. The experiments used KMnO4 as the source of Mn and the resulting Birnessite and Cryptomelane precipitates were washed with 18 Mn/cm NANOpure water at the end of syntheses. Several state-of-the-art solid state techniques were used to characterize the Mn-based oxide mineral phases. Based on the literature …

Investigation Of Novel Thiol "Click" Reactions, Justin William Chan

Dissertations

The thio-Michael addition reaction is traditionally considered a base catalyzed reaction which involves high catalyst concentrations and long reaction times. This reaction utilizes potent, simple nucleophiles to catalyze the reaction, decreases the catalyst concentration and greatly increases the reaction times. The free radical mediated thiol-ene click reaction uses light or heat and an initiator to catalyze the rapid and quantitative addition of thiols to most electron rich enes without the formation of side products and in the absence of solvent. Recently, the thiol-ene click reaction has been exploited for these reasons in materials science and organic synthesis. The research herein …

Investigation Of The Relationship Between Polymer Structures And Thermal, Mechanical, Viscoelastic Properties, Ethem Kaya

Dissertations

The research presented in this dissertation involves four distinct areas: physical crosslinking systems, UV curable coatings for enhanced oxygen and carbon dioxide barrier properties, synthesis, and investigation of melting behavior/crystallinity relations of linear polyamides with long alkyl chains, and synthesis and characterization of cyclic diamides as precursors to linear polyamides 6 4.

The physical crosslinking section involves synthesis of monomers and polymers bearing cyclodextrin and adamantane pendent groups, and investigation of non-covalent interactions between these polymers (Chapter II). Two methacrylate monomers bearing cyclodextrin and adamantane were synthesized, and copolymerized with poly(ethylene glycol) methyl ether methacrylate. The specific interaction between copolymers …

Application Of Molecular Modeling In The Noncovalent Dispersion Of Carbon Nanomaterials, Praveen Kumar Madasu

Dissertations

Molecular modeling is a powerful tool to better understand the intermolecular interactions of carbon nanostructures. It provides structures and energies not easily obtainable from experiments and predicts properties that can be tested experimentally. Intermolecular interactions play an important role in the aggregation of various carbon nanomaterials. Three molecular modeling studies of carbon nanomaterial dispersions are presented in this dissertation, with an emphasis on illustrating how effective these theoretical techniques are in providing insight on the selection of dispersion additives. To achieve our goals, we employed molecular mechanics based methods, along with semi-empirical methods, and quantum mechanical methods, such as density …

Random And Block Copolymers Of Poly(Dodecamethyleneterephthalamide), Theodore Frank Novitsky Jr.

Dissertations

The following dissertation focuses on the synthesis and characterization of poly(dodecamethylene terephthalamide) (PA-12,T) and novel copolymers. Chapter I details the synthesis of PA-12,T homopolymer by melt condensation polymerization. A series of homopolymers with different molecular weights were obtained by adjusting the stoichiometry of the polymerization using 1,12-diaminododecane, terephthalic acid and benzoic acid. End group 13C NMR spectroscopy resonances were obtained by correlating peak intensities with intrinsic viscosity values. From the NMR data, total end group concentrations and molecular weights were determined for each sample. The data exhibited a linear trend when plotting log (IV) versus log (Mn), and previously unknown …

Preparation And Characterization Of Thiol Based Polymeric Materials, Junghwan Shin

Dissertations

The thiol click-type reaction is one of the most efficient chemical processes that can undergo at room temperature in the benign organic solvent providing excellent opportunity in the fabrication of new materials as well as development of new manufacturing processes. Moreover, the versatility of thiol click-type reactions with many different functional groups such as ene, yne, epoxy, isocyanate, and alkyl halide is the important aspect that should be differentiated from the classic azide-alkyne click chemistry. Although, there are tremendous studies on many areas using thiol click-type reactions, the efficiency and utilities for the material applications have been barely explored. Especially, …

Polymeric Carbon Nanocomposites - Preparation, Characterization, And Properties, Lucia Veca

All Dissertations

Excellent thermal properties of carbon nanomaterials such as carbon nanotubes and newly discovered graphene make them the filler of choice for the development of thermal management materials. Graphene has been viewed as “ unrolled single-walled carbon nanotube and as a wonder material with many superlatives to its name ” thus there is an excessive interest in developing new synthetic routes towards large scale production of high quality graphene nanosheets.
In this dissertation, we report different methods that could further exfoliate the commercially available expanded graphite to nanometer sized carbon structures, “carbon nanosheets ”, for their use in highly thermal conductive …

Synthesis, Modification Of Mesoporous Carbons And Their Application In Polymer Electrolyte Membrane Fuel Cells, Bing Liu

All Dissertations

Mesoporous carbon materials of carbon xerogel (CX) and silica-templated carbon (MC) were synthesized and explored as catalyst supports alternative to the most-commonly-used carbon black (CB) support, for polymer-electrolyte-membrane fuel cell (PEMFC) application. Pt catalyst was loaded on these carbons and electrodes were fabricated from them. These Pt-loaded carbon supports were characterized with XRD, TEM, ex-situ and in-situ cyclic voltammetry, etc. The fabricated electrodes were evaluated in single-cell testing in comparison with commercial CB-supported Pt catalyst fabricated electrodes. The experimental results showed that CX-supported Pt catalyst had close or better performance than that of CB-supported Pt, possibly due to CX's 3-D …

Development Of A Novel Lysophosphatidic Acid Activity Probe To Identify And Characterize New Protein Targets, Leah M. Cuthriell

Masters Theses

Lipids are categorized according to their biological function. Phospholipids, glycolipids, and cholesterol are bulk membrane lipids that offer structure and support to the cells and organelle membranes. Signaling lipids include diacylglycerol, phosphatidic acid, and lysophosphatidic acid (LPA). These are low abundance lipids that are active in various pathways. LPA acts through GPCR receptors to activate G or beta mediated stimulation of phospholipase C leading to phosphatidylinositol-(4,5)-bisphosphate hydrolysis, G_i mediated inhibition of adenyl cyclase, and G_i mediated stimulation of the mitogenic Ras- MAP kinase. To further elucidate the biological activity of LPA and potentially identify new LPA binding receptors, …

The Impact Of Iron Deprivation On The Metabolism Of Escherichia Coli As Measured By Targeted Hplc-Ms/Ms Based Metabolomics, Jamie Rhea Light

Masters Theses

Iron is a necessity for all living organisms, and bacteria typically need an internal concentration of iron in the micromolar range.¹ This becomes quite problematic, especially in pathogenic bacteria, because the concentration of free ions within the human body is only 10^-24 Molar due to iron binding proteins, like transferrin.¹ In order to circumvent this problem, bacteria produce small iron chelating molecules called siderophores.¹ The bacteria utilized for this study, a K-12 derivative of Escherichia coli, produce only one siderophore, enterobactin. Not only is the transcription of genes associated with iron acquisition initiated in response …

Synthesis And Development Of Novel Fullerene-Based Structures For Photovoltaics, Electronic Applications And Mri Contrast Agents, Manuel Chaur

All Dissertations

Metallic nitride endohedral metallofullerenes (EMFs) are one of the most interesting types of metallofullerenes due to their high yields and interesting electronic properties. The synthesis of these compounds allows the encapsulation of different metals inside fullerenes making it possible to combine the properties of the metal with those of the fullerene. Their interesting electrochemical and optical features make them potential candidates for several applications such as molecular electronics, biomedical imaging, non-linear optical devices, and magnetic resonance imaging (MRI) agents. This thesis reports the synthesis of novel metallic nitride EMFs based on Gd, Nd, Pr, Ce and La. These families of …

Synthesis And Characterization Of Metallic, Core-Shell And Composite Nanoparticles, Amar Kumbhar

All Dissertations

ABSTRACT
Silver nanoparticles exhibit size, shape and the surrounding dielectric medium dependent optical properties (scattering and absorption) in the visible spectral region. These optical properties can be explained in terms of the collective oscillation of the 'free conduction band electrons' or 'surface plasmons' induced by an external electromagnetic field. Dipole and Quadrupole Plasmon resonances have been observed for silver particles less than 100nm in diameter prepared using various synthetic techniques. However higher order resonances have been elusive due to lack of experimental techniques to prepare colloidal solutions of large silver nanoparticles in the size range above 100nm. Controlled hydrogen reduction …

Development Of A Fluorescent Probe For Determination Of Water Transport In Subcellular Organelles, Adriana Chaurra-Arboleda

All Dissertations

Water transport has been widely studied in a variety of cells and isolated membranes. However, the intrinsic complexity related with the study of intracellular processes has delayed the development of an analytical technique for the study of water transport in subcellular compartments of living cells. This study represents the development and application of a ratiometric fluorescent probe to study water transport in endocytic organelles of intact living cells. The probe is based on the use of a D₂O-sensitive fluorophore, Lucifer yellow dextran (LY-dex), together with a D₂O-insensitive fluorophore, Alexa fluor 546 dextran (AF546-dex), used as an …

Biological Conversion Of Hemicellulose Extract Into Value-Added Fuels And Chemicals, Sara Lynn Walton

Electronic Theses and Dissertations

The research presented in this thesis describes the fermentation of hemicellulose extracts to produce ethanol and lactic acid. Hardwood hemicellulose extracts made at a variety of conditions using the green liquor and hot water extraction processes were characterized and then fermented by Escherichia coli K011 and Bacillus coagulans MXL-9. Hemicellulose extracts were found to contain a dilute amount of xylo-oligosaccharides and acetic acid as the major components, and many minor components including other organic acids, lignin-derived phenolics, and sugar degradation products. In order to generate ethanol economically, the fermentation must produce at least a 4% ethanol solution, which requires a …