Physical Sciences and Mathematics Commons^™

Design, Synthesis And Characterization Of Nanosensors For Nerve Gas Agents, Thushara Gunasinghe

Masters Theses

This research is focused on the design synthesis and characterization of nanosensors to detect the nerve gas agents such as sarin at very low concentration levels (parts per billion and lower) which is very important to combat terrorism. Nanosensors constructed by the bottom up approach could provide the low sensitivity levels and high selectivity required for nerve gas detection. The sensing mechanism exploits the inherent properties of nanomaterials and signal amplification by signal transduction. The components of a nanoparticle-fluorescent monomer-nanomolecule-receptor (NMNR) sensor have been designed, synthesized, and characterized successfully. Interaction of the components of NMNR sensor with a model nerve …

Investigation Of The Anisotropy Of Dissipation Processes In Single Crystal Of Yba2cu3o7-D System, J Chigvinadze, A. Lashvili, Juana Acrivos, T. Machaidze, T. Wolf

Faculty Publications, Chemistry

By means of contactless mechanical method of the measurement of energy losses in superconductors, the anisotropy of dissipation processes has been studied in single crystal high-temperature layered superconductors of Yba2Cu3O7-d system, being in mixed state. The observed anisotropy of energy losses indicates the possibility of the existence of the symmetry of order parameter of dx2-y2 type in these single crystals.

A Short Synthesis Of The Common Dihydropyran Segment Of The Antifungal Agents Ambruticin And Jerangolid A, Julie Lukesh, William Donaldson

Chemistry Faculty Research and Publications

The dihydropyranyl segment common to ambruticin and jerangolid A was prepared in six steps (31.7% yield) from (S)-2-benzyloxypropanal via silyloxydiene cyclocondensation, followed by C-glycosidation, and eventual epimerization at C18.

Spectroscopic Studies Of Inclusion Host-Guest Complexes Between Cyclophane Corrals And Polcyclic Aromatic Hydrocarbons, Mark O'Brien

Masters Theses & Specialist Projects

Cyclophanes are macromolecules that are known to effectively bind with molecules to form host-guest complexes. Several cyclophane molecules, referred to as corrals (1-6) by their founders, have been synthesized. The characterization of these compounds and their complexes has been investigated using combined spectroscopic and theoretical methods. Hostguest interactions of cyclophane-anthracene (C-A), cyclophane-9-fluorenone (C-F) and cyclophane-pyrene (C-P) complex systems in dichloromethane are presented in this thesis. The stability constants, log Ka, for the C-A, C-F and C-P complexes are determined using absorption and fluorescence spectroscopy. Heats of formation of corral 2 complexes were determined by measuring the complex association constants at …

Synthesis And Characterization Of Polyaminopolycarboxylic Acid Analogs Of Edta And Their Transition Metal Complexes, Martha Watson

Masters Theses & Specialist Projects

Polyaminopolycarboxylic acids have been studied for their ability to complex with various transition metal ions. Polyaminopolycarboxylic acids are of particular interest due to their ability to form multiple chelate rings with transition metal ions. Three analogs of EDTA have been successfully synthesized and characterized by i3C NMR: 1,3 PDTA (1,3-propylenediaminetetraacetic acid), 1,3-PDTP (1,3-propylenediaminetetrapropionic acid) and EDTP (ethylenediaminetetrapropionic acid). These ligands were then combined with copper (II), iron (III), cobalt (II) and nickel (II) to form complexes. The complexes formed were analyzed using UV-Vis, and the stability constants of the complexes were determined using potentiometry.

Surface Functionalization Of Polymer Substrates And Nanoparticles Via Pulsed Plasma Polymerization Process, Jing Wu

Chemistry & Biochemistry Theses

This thesis investigates the RF plasma polymerizations of chlorinated saturated linear monomer 1,1,1-trichloroethane and the dicarboxylic citraconic acid. It utilizes a variable duty cycle plasma technique to provide film chemistry control during the plasma polymerization process. Film chemical compositions and deposition rates were characterized as functions of the plasma processing conditions. In each system studied, spectroscopic analyses revealed that large progressive changes in film compositions were obtained with sequential variations in plasma duty cycles in the plasma polymerization of both 1,1,1-trichloroethane and citraconic acid. The plasma approach was also employed to modify the surfaces of nanoparticles. Thin polymeric films, produced …

Structure-Activity Relationship Studies On Thioxolone Compounds As Inhibitors Of Human Carbonic Anhydrase Ii, Jared Nyabuto Orwenyo

Masters Theses

Carbonic anhydrase II (CA II) is a zinc metalloenzyme that catalyzes the reversible hydration of carbon dioxide. The role of this reaction in physiology has made it a target of many therapeutic approaches. Most CA II inhibitors currently known are sulfonamide-based and this is the only functional group incorporated into rationally designed CA II inhibitors. Thioxolone (6-hydroxy-1, 3-benzoxathiol-2-one), is a non-sulfonamide that has been found to have CA II inhibitory activity.

Thioxolone and its analogs were studied to evaluate the inhibition activity that can be achieved upon modification of the thioxolone molecule. IC₅₀ values and dissociation constants were determined …

47th Rocky Mountain Conference On Analytical Chemistry

Rocky Mountain Conference on Magnetic Resonance

Final program, abstracts, and information about the 47th annual meeting of the Rocky Mountain Conference on Analytical Chemistry, co-endorsed by the Colorado Section of the American Chemical Society and the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Denver, Colorado, July 31 - August 4, 2005.

A Modified Poisson–Boltzmann Analysis Of The Capacitance Behavior Of The Electric Double Layer At Low Temperatures, Douglas Henderson, L. B. Bhuiyan, C. W. Outhwaite

Faculty Publications

The modified Poisson–Boltzmann theory is used to analyze the anomalous behavior of the electric double layer capacitance for small surface charge at low temperatures and densities. Good agreement is found with simulation and recent density-functional theory results. Negative adsorption is also found in line with theory and simulation. An unsatisfactory feature is the relatively poor structure in this region due to the inherent approximations in the theory. This feature is unimportant in relation to the capacitance results but has implications when calculating adsorption properties.

Incorporation Of Factor Va Into Prothrombinase Is Required For Coordinated Cleavage Of Prothrombin By Factor Xa, Michael A. Bukys, Melissa A. Blum, Paul Y. Kim, Nicole Brufatto, Michael E. Nesheim, Michael Kalafatis

Chemistry Faculty Publications

Prothrombin is activated to thrombin by two sequential factor Xa-catalyzed cleavages, at Arg271 followed by cleavage at Arg320. Factor Va, along with phospholipid and Ca2+, enhances the rate of the process by 300,000-fold, reverses the order of cleavages, and directs the process through the meizothrombin pathway, characterized by initial cleavage at Arg320. Previous work indicated reduced rates of prothrombin activation with recombinant mutant factor Va defective in factor Xa binding (E323F/Y324F and E330M/V331I, designated factor VaFF/MI). The present studies were undertaken to determine whether loss of activity can be attributed to selective loss of efficiency at one or both of …

Hard-Sphere Radial Distribution Function Again, Andrij Trokhymchuk, Douglas Henderson, Ivo Nezbeda, Jan Jirsak

Faculty Publications

A theoretically based closed-form analytical equation for the radial distribution function, g(r), of a fluid of hard spheres is presented and used to obtain an accurate analytic representation. The method makes use of an analytic expression for the short- and long-range behaviors of g(r), both obtained from the Percus-Yevick equation, in combination with the thermodynamic consistency constraint. Physical arguments then leave only three parameters in the equation of g(r) that are to be solved numerically, whereas all remaining ones are taken from the analytical solution of the Percus-Yevick equation.

Analysis Of Liquid-Phase Chemical Detection Using Guided Shear Horizontal-Surface Acoustic Wave Sensors, Zhonghui Li, Yolanda Jones, Jeanne M. Hossenlopp, Richard Cernosek, Fabien Josse

Chemistry Faculty Research and Publications

Direct chemical sensing in liquid environments using polymer-guided shear horizontal surface acoustic wave sensor platforms on 36° rotated Y-cut LiTaO3 is investigated. Design considerations for optimizing these devices for liquid-phase detection are systematically explored. Two different sensor geometries are experimentally and theoretically analyzed. Dual delay line devices are used with a reference line coated with poly (methyl methacrylate) (PMMA) and a sensing line coated with a chemically sensitive polymer, which acts as both a guiding layer and a sensing layer or with a PMMA waveguide and a chemically sensitive polymer. Results show the three-layer model provides higher sensitivity than the …

Development Of A Model For The Kinetics And Mechanism Of Nitrogenase, Phillip E. Wilson

Theses and Dissertations

Nitrogenase has a central role in the global nitrogen cycle as the enzyme that catalyzes the reduction of atmospheric N2 to NH3. Fixed nitrogen is generally limiting in the environment and in agriculture, so nitrogenase has received much attention as an alternative to nitrogen fertilizers. Characterizing the mechanism of nitrogenase is the goal of this work. The molybdenum nitrogenase enzyme system is comprised of the MoFe protein and the Fe protein. Interactions between these proteins and nucleotides are crucial to catalysis. An important approach to characterize these interactions is to correlate the kinetics of nitrogenase catalysis to a mechanism based …

Angiotensin Ii-Mediated Regulation Of The Human Angiotensin Ii Type 1 Receptor Gene, Xylophone Vijai Aasee Victor

Theses and Dissertations

The physiological responses of angiotensin II (Ang II) are mediated across the cell membrane through the angiotensin II type 1 receptor (AT1R), a heptahelical membrane protein coupled to trimeric G-proteins on the cytosolic side. AT1R on binding its ligand, Ang II, leads to downregulation of cell-surface receptor and also its mRNA. We have investigated whether the 3'- and 5'-untranslated regions of the human AT1R mRNA mediate the degradation of hAT1R mRNA by post-transcriptional mechanisms in human adrenocortical carcinoma cell line (H295R cells). Protein kinase C (PKC) activator, phorbol-12-myristate-13-acetate (PMA), showed that the downregulation of hAT1R mRNA is mediated by the …

Tris(Ethylenediamine)Cobalt(Iii) Nonaiododibismuthate, Andrea M. Goforth, Rachael E. Hipp, Mark D. Smith, Leroy Peterson Jr., Hans-Conrad Zur Loye

Faculty Publications

The asymmetric unit of the title compound, [Co(C₂H₈N₂)₃][Bi₂I₉], crystallizes in the orthorhombic space group Cmc2₁. The asymmetric unit contains half of a [Co(en)₃]³⁺ cation (en is ethylenediamine) and half of a [Bi₂I₉]^3- anion. Both species are located on mirror planes, requiring the [Co(en)₃]³⁺ cation to be present as a statistically disordered mixture of both enantiomeric forms. Crystals were grown solvothermally from an ethanol-water solvent mixture using rac-[Co(en)₃]I₃ and bismuth triiodide …

Deconvolution Of The Co3O4(110) Fuchs–Kliewer Phonon Spectrum, E.M. Marsh, S.C. Petitto, G.S. Harbison, K.W. Wulser, Marjorie Langell

Marjorie A. Langell Publications

The Fuchs–Kliewer phonon spectrum of single crystal Co₃O₄(110) has been treated with a Fourier transform log deconvolution method, which removes multiple scattering features from the single loss spectrum. Auger electron spectroscopy (AES), x-ray photoelectron spectroscopy (XPS) and low-energy electron diffraction (LEED) were first used to characterize the Co₃O₄ crystal establishing the cleanliness, composition, and order of the (110) surface. High resolution electron energy loss spectroscopy (HREELS) was then used to obtain the phonon spectrum for an incident electron energy of 3.77 eV. Due to the strong dipole cross section for the Fuchs–Kliewer phonon …

Spm Oxidation And Parallel Writing On Zirconium Nitride Thin Films, N. Farkas, J. R. Comer, G. Zhang, Edward A. Evans, R. D. Ramsier, J. A. Dagata

Chemical, Biomolecular, and Corrosion Engineering Faculty Research

Systematic investigation of the SPM oxidation process of sputter-deposited ZrN thin films is reported. During the intrinsic part of the oxidation, the density of the oxide increases until the total oxide thickness is approximately twice the feature height. Further oxide growth is sustainable as the system undergoes plastic flow followed by delamination from the ZrN-silicon interface keeping the oxide density constant. ZrN exhibits superdiffusive oxidation kinetics in these single tip SPM studies. We extend this work to the fabrication of parallel oxide patterns 70 nm in height covering areas in the square centimeter range. This simple, quick, and well-controlled parallel …

Keto-Carboxylic Acids In Carbonaceous Meteorites, Aliah C. Dugas

Electronic Dissertations and Theses

The Murchison meteorite is the best-characterized carbonaceous meteorite with respect to organic chemistry and is generally used as references for organic compounds in extraterrestrial material. Among the classes of organic compounds found in the meteorite are amino acids, carboxylic acids, hydroxy acids, purines, and pyrimidines. Absent among today's critically important biological compounds reported in carbonaceous meteorites are keto acids, i.e., pyruvic acid, acetoacetic acid, and higher homologs. These compounds are key intermediates in such critical processes as glycolysis and the citric acid cycle. In this study several individual meteoritic keto acids were identified by gas chromatography-mass spectrometry (GC-MS). All compounds …

Melting Temperature Of Ice IH Calculated From Coexisting Solid-Liquid Phases, J. Wang, S. Yoo, Jaeil Bai, James R. Morris, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

The purpose of this paper is twofold: (1) to compute the melting temperature (T_m) of ice I_h with both TIP4P and TIP5P models by using the two-phase coexistence method and to compare with previously obtained T_m; (2) to compute the T_m using recently improved TIP4P and TIP5P models, namely, the TIP4P-Ew (Ref. 6) and TIP5P-Ew (Ref. 7) models. Both models are developed specifically for use with Ewald techniques. The TIP4P-Ew model, in particular, has shown substantial improvement over the original TIP4P model as it can reproduce the density maximum at about 274 K, …

The Design And Synthesis Of Novel Chaetomellic Acid A Analogues, Mark F. Mechelke, Jacquelyn C. Webb, Jessica L. Johnson

Chemistry Faculty Publications

Chaetomellic acid A is an alkyl dicarboxylic acid isolated from the fermentation of Chaetomella acutiseta. Chaetomellic acid A has been shown to be a potent, highly specific inhibitor of RAS farnesyl protein transferase (FPTase). The association between RAS proteins and cancer has made chaetomellic acd A a potential chemotherapeutic agent. Two novel chaetomellic acid A analogues have been prepared that incorporate aromoatic rings in the alkyl tail. It is anticipated that these compounds will bind more tightly to the FPTase active site than the natural product due to intermolecular interactions between the aromatic rings in the tail and the …

Photoinduced One-Electron Reduction Of Alkyl Halides By Dirhodium(Ii,Ii) Tetraformamidinates And A Related Complex With Visible Light, Dean Johnston

Chemistry Faculty Scholarship

Various substituted dirhodium tetraformamidinate complexes, Rh(2)(R-form)(4) (R = p-CF(3), p-Cl, p-OCH(3), m-OCH(3); form = N,N'-diphenylformamidinate), and the new complex Rh(2)(tpgu)(4) (tpgu = 1,2,3-triphenylguanidinate) have been investigated as potential agents for the photoremediation of saturated halogenated aliphatic compounds, RX (R = alkyl group). The synthesis and characterization of the complexes is reported, and the crystal structure of Rh(2)(tpgu)(4) is presented. The lowest energy transition of the complexes is observed at approximately 870 nm and the complexes react with alkyl chlorides and alkyl bromides under low energy irradiation (lambda(irr) > or = 795 nm), but not when kept in the dark. The metal-containing …

Expandable Graphite/Polyamide-6 Nanocomposites, Fawn Marie Uhl, Qiang Yao, Hiroyoshi Nakajima, Evangelos Manias, Charles A. Wilkie

Chemistry Faculty Research and Publications

Polyamide-6 (PA-6)/graphite nanocomposites were prepared by melt blending, using a variety of graphites, including virgin graphite, expandable graphites and expanded graphite. The resulting nanocomposites were characterized by X-ray diffraction, thermogravimetric analysis, cone calorimetry, and tensile mechanical analysis. Nanocomposite formation does occur, as denoted by the nanometre dispersion of graphite layers in the polymer matrix, and the dispersion depends on the graphite treatment. The material properties of the resulting composites are improved relative to the virgin/unfilled polymer; in particular, there is an enhancement of the thermal stability without any significant deterioration of the mechanical properties.

Promoting Learning Through Peer Group Work, Christine O'Connor, Renli Ma

Conference Papers

The session aimed to help the Summer School participants develop tasks and assessment strategies of peer group work in their own teaching.

Fire Retardancy Of Vinyl Ester Nanocomposites: Synergy With Phosphorus-Based Fire Retardants, Grace Chigwada, Panchatapa Jash, David D. Jiang, Charles A. Wilkie

Chemistry Faculty Research and Publications

Vinyl ester (PVE) nanocomposites were prepared using both clay and polyhedral oligosilsesquioxanes (POSS) as the nano-dimensional material. From cone calorimetric data, it was shown that both POSS and clay affect the flammability of the nanocomposites to the same extent. To improve on the flame retardancy, the nanocomposites were combined with phosphorous-containing fire retardants (FRs) and the result compared to the benchmark halogen-containing system. The use of the cone calorimeter to investigate the fire properties of these nanocomposites showed a great reduction in peak heat release rate (PHRR) in the presence of phosphate and slight improvements in average mass loss rate …

Protection Against Experimental Autoimmune Myocarditis Is Mediated By Interleukin-10-Producing T Cells That Are Controlled By Dendritic Cells, Ya Li, Janet S. Heuser, Stanley D. Kosanke, Mark E. Hemric, Madeleine W. Cunningham

Faculty Publications and Presentations

Experimental autoimmune myocarditis (EAM) can be induced in the Lewis rat by cardiac myosin or its cryptic S2-16 peptide epitope (amino acids1052 to 1076). To investigate cellular mechanisms and the role of antigen-presenting cells in regulation of myocarditis, we induced protection against EAM in Lewis rats by administration of S2-16 peptide in incomplete Freund’s adjuvant (IFA). Protection to EAM was associated with activation of S2-16-reactive splenocytes secreting high levels of interleukin (IL)-10 and reduced levels of interferon- and IL-2. Adoptive transfer of S2-16:IFA-induced splenocytes producing IL-10 suppressed myocarditis induction in syngeneic recipients, suggesting their regulatory cell nature. However, exposure of …

Polymers With Pendant Coumarins: Synthesis And Characterization Of Polystyrenes And Polymethacrylates With Pendant Coumarin Moieties, T. Christopher Corkery

Chris Corkery

No abstract provided.

An Analysis Of The Chemical Processes In The Smoke Plume From A Savanna Fire, Jorg Trentmann, Robert J. Yokelson, Peter V. Hobbs, Tanja Winterrath, Ted J. Christian, Meinrat O. Andreae, Sherri A. Mason

Chemistry and Biochemistry Faculty Publications

[1] Photochemistry in young plumes from vegetation fires significantly transforms the initial fire emissions within the first hour after the emissions are injected into the atmosphere. Here we present an investigation of field measurements obtained in a smoke plume from a prescribed savanna fire during the SAFARI 2000 field experiment using a detailed photochemical box-dilution model. The dilution used in the model simulations was constrained by measurements of chemically passive tracers (e.g., CO) near and downwind of the fire. The emissions of the dominant carbonaceous compounds, including oxygenated ones, were taken into account. The field measurements revealed significant production of …

Synthesis And Characterization Of Azole Isoflavone Inhibitors Of Aromatase, John C. Hackett, Young Woo Kim, Bin Su, Robert W. Brueggemeier

Chemistry Faculty Publications

The synthesis and biological evaluation of a series of 2-azole and 2-thioazole isoflavones as potential aromatase inhibitors are described. Differences in inhibitory activity of triazole and imidazole inhibitors are rationalized with density functional theory to expose a key difference in the electronic structure of these molecules. In addition, difference binding spectra of inhibitors to immunoaffinity-purified aromatase produces classical Type II spectra consistent with coordination of the nitrogen lone pair electrons to the aromatase P450 heme.

Dissolution, Reactor, And Environmental Behavior Of Zro2-Mgo Inert Fuel Matrix: Neutronic Evaluation Of Zro2-Mgo Inert Fuels, E. Shwageraus, A. Galperin, E. Fridman, S. Kolesnikov

Fuels Campaign (TRP)

This report presents results of the analysis performed within the framework of “Dissolution, Reactor, and Environmental Behavior of ZrO₂-MgO Inert Fuel Matrix” project managed by University of Nevada at Las Vegas, Harry Reid Center for Environmental Studies. The main objective of the study was to explore the basic neutronic feasibility of using MgO-ZrO₂ as inert fuel matrix for Pu recycling in conventional Light Water Reactors (LWR).

Afci Quarterly Input – Unlv April Through June, 2005, Harry Reid Center For Environmental Studies. Nuclear Science And Technology Division

Transmutation Research Program Reports (TRP)

Quarterly report highlighting research projects, activities and objectives of the Transmutation Research Program at the Nuclear Science & Technology Division, Harry Reid Research Center.

The University of Nevada, Las Vegas supports the AFCI through research and development of technologies for economic and environmentally sound refinement of spent nuclear fuel. The UNLV program has four components: infrastructure, international collaboration, student-based research, and management and program support.