Chemistry Commons^™

A Novel Method For Confirming The Presence Of Volatile Reduced Sulfide Compounds Via Inductively Coupled Plasma-Optical Emission Spectroscopy, Krystal Lynne Parker

Master's Theses

Millions of dollars in destruction in the past decade have resulted from the use of Chinese drywall in homes. There are also potential health hazards related to this corrosive material. As such, it is important to find a way to identify Chinese drywall. Drywall can be tested for certain markers, such as strontium, sulfur, and carbonates to identify it as corrosive Chinese drywall. The laboratory preparation and analysis should be efficient and cost effective. The methods previously used, such as an X-ray fluorescence gun have had issues with getting a proper reading due to the layers of other materials found …

Oxidative Stability Of Conjugated Linoleic Acid Rich Soy Oil Obtained By Heterogeneous Ruthenium Catalysis, Saurabh Ravindra Lele

Graduate Theses and Dissertations

Conjugated linoleic acid (CLA) has multiple health benefits but it is difficult to obtain sufficient CLA in a healthy diet to obtain the clinical effects. A CLA rich-soy oil (CLARSO) with up to 20% CLA has been produced by heterogenous catalysis but no studies of its oxidative stability have been reported. CLARSO and soy oil primary and secondary oxidation products were measured at 50oC in the dark. The CLARSO was less stable than soy oil but adsorption bleaching improved its oxidative stability. However, induction times were dependent on the analytical method used. Fatty acid oxidation kinetics was determined by measuring …

Dispersion Of Em Waves, Ronald Lovett

Topics in Quantum Mechanics

No abstract provided.

Fourier Transform, Ronald Lovett

Topics in Quantum Mechanics

No abstract provided.

Neutron Study Of Structure And Dynamics Of Rigid Polymers, Naresh Osti

All Dissertations

The structure and the dynamics in two different classes of rigid polymers; ionomers and rigid luminescent polymers, have been investigated predominantly by neutron techniques. Rigidity of the backbones of both polymers affects their properties. For ionomers, it affects transport pathways, therefore, their applications for energy and separation membranes. In luminescent polymers, it determines the conformations of the chains and their electro-optical response. One group of the polymers consists of rigid hydrophobic para-phenylene backbone decorated with pendant phenyl side chains functionalized with sulfonic acid (SPP). The other family of polymers consists of poly para-phenyleneethynylene (PPE) backbone that becomes conjugated upon conformational …

Development And Application Of Combined Quantum Mechanical And Molecular Mechanical Methods, Rui Lai

Department of Chemistry: Dissertations, Theses, and Student Research

Compromising of computational cost and accuracy, combined quantum mechanical and molecular mechanical (QM/MM) methods are practical methods for studying large molecular systems. The use of induced dipole polarizable force fields can significantly improve the accuracy of MM and QM/MM methods. However, induced dipole models tend to overestimate the polarization energy at short interaction distances. Damping functions can be applied to reduce the over polarization. MM-MM damping schemes have been developed to correct the overestimated polarization between MM atoms; QM-MM damping scheme has not been developed. In this thesis, a QM-MM damping scheme is developed for the damping of the MM …

Synthesis And Characterization Of Complex Molecular Assemblies On Surfaces, Nitesh Madaan

Theses and Dissertations

The research presented in this dissertation is focused on the construction of complex molecular structures on planar gold and silicon dioxide surfaces using a variety of surface modification techniques, along with thorough surface characterization at each modification step. The dissertation is structured into six separate chapters. In Chapter 1, an introduction to the importance and implications of molecular level surface modification, commonly employed surface modification methods, and available surface characterization techniques is presented. Chapter 2 shows applications of novel methodologies for the functionalization of gold surfaces using alkane dithiol self-assembled monolayers and thiol-ene click chemistry. The resulting functionalized gold substrates …

Chaperone-Mediated Folding And Assembly Of Β-Propeller Proteins Into Cellular Signaling Complexes, Rebecca L. Plimpton

Theses and Dissertations

G protein signaling depends on the ability of the individual subunits of the G protein heterotrimer to assemble into a functional complex. Formation of the G protein βγ (Gβγ) dimer is particularly challenging because it is an obligate dimer in which the individual subunits are unstable on their own. Recent studies have revealed an intricate chaperone system that brings the Gβ and Gγ subunits together. This system includes the cytosolic chaperonin containing TCP-1 (CCT) and a co-chaperone phosducin-like protein 1 (PhLP1). Two key intermediates in the Gβγ assembly process, the Gβ-CCT and the PhLP1-Gβ-CCT complexes, were isolated and their structures …

Utilization Of Aqueous Raft Prepared Copolymers To Improve Anticancer Drug Efficacy, Andrew Christopher Holley

Dissertations

The advent of controlled radical polymerization (CRP) techniques, along with advancements in facile conjugation chemistry, now allow synthetic tailoring of precise, polymeric architectures necessary for drug/gene delivery. Reversible addition- fragmentation chain transfer (RAFT) polymerization and its aqueous counterpart (aRAFT) afford quantitative control over key synthetic parameters including block length, microstructure, and placement of structo-pendent and structo-terminal functionality for conjugation of active agents and targeting moieties. The relevance of water-soluble and amphiphilic (co)polymers synthesized by RAFT for in vitro delivery of therapeutics in biological fluids is an especially attractive feature. In many cases, polymerization, binding, conjugation, …

Enzyme, Cosolvent, And Substrate Interactions In Ple Hydrolysis Reactions And Evaluation Of The Stability Of An Unnatural Glutathione Analogue, Maureen Elizabeth Smith

Dissertations

Prochiral diester malonates have been hydrolyzed in the presence of Pig Liver Esterase (PLE). Several of the diesters produced the respective half-ester in moderate to high enantioselectivity. A series of cosolvent assays were performed to evaluate the ability of the cosolvent to influence the enantioselective outcome of the hydrolysis reactions. Ethanol produced the largest changes in enantioselectivity of all solvents evaluated. The isoenzymes of PLE were also evaluated and provided very different enantioselective outcomes than that of crude PLE. A series of NMR titrations was performed to explore the interactions between the substrates and ethanol cosolvents.

Improvements to our previously …

Molecular Probes For The Detection Of Zn2+ And Fe3+ Ions, Erendra Manandhar

Dissertations

A number of molecular probes have been designed and synthesized for the detection of Zn²⁺ and Fe³⁺ ions. Two types of functional groups have been incorporated into the molecular scaffolds to utilize different fluorescent mechanisms. The first class of receptors contains a pyrene moiety. These molecular probes use the excimer mechanism for the detection of Zn²⁺ ion. The probes work well in an organic solvent with a detection limit of 20 nM (one ppb). Alternatives are made to make them water soluble, but this proved to be difficult. An interesting ion-induced self-assembly system will also be discussed. …

Misalignments: Challenges In Cultivating Science Faculty With Education Specialties In Your Department, Seth D. Bush, Nancy Pelaez, James A. Rudd Ii, Michael T. Stevens, Kimberly D. Tanner, Kathy S. Williams

PIBERG Publications

Science Faculty with Education Specialties (SFES) are increasingly being hired across the United States. However, little is known about the motivations for SFES hiring or the potential or actual impact of SFES. In the context of a recent national survey of US SFES, we investigated SFES perceptions about these issues. Strikingly, perceptions about reasons for hiring SFES were poorly aligned with perceptions about potential and actual contributions reported by SFES themselves, and the advice they extended to beginning SFES was varied. While preparation of future teachers and departmental teaching needs were common reasons offered for SFES hiring, the potential and …

Sign Me Up! Determining Motivation For High School Chemistry Students Enrolling In A Second Year Chemistry Course, Nilda N. Camarena

Theses and Dissertations - UTB/UTPA

A sample of 108 Pre-AP Chemistry students in Texas participated in a study to determine motivational factors for enrolling in AP Chemistry and University Chemistry. The factors measured were academic attitude, perceptions of chemistry, confidence level in chemistry, and expectations/experiences in the chemistry class. Students completed two questionnaires, one at the beginning of the year and one at the end. Four high school campuses from two school districts in Texas participated. Two campuses were traditional high schools and two were smaller magnet schools. The results from this study are able to confirm that there are definite correlations between academic attitudes, …

Tuning Responsiveness Of Polypeptide Based Block Copolymers For Drug Delivery, Ashley J. Johnson

Dissertations

The goal of this dissertation was to tune the pH response and self-assembled morphologies of amphiphilic polypeptide block copolymers for use as drug delivery vehicles. Poly(L-lysine) and poly(L-glutamtic acid) are responsive, ionizable polypeptides that undergo secondary structure transitions, from α-helix to random coil, whereby the change in conformation of the peptide chain results in changes to the global morphology of a self-assembled system. The main focus of this work was to understand how changes in the polymer composition and the local environment can lead to control over the behavior of the overall system. First, the responsive behavior of poly(L-lysine) block …

Spectroscopy And Gas-Phase Binding Of Modified Desferrioxamine B Indicator Displacement-Based Sensors, William Scott Jones

Dissertations

A coupling reaction has been used to successfully synthesize two novel probes utilizing coumarin derivatives as fluorophores. The structure, spectroscopy, and thermodynamics of these probes were characterized and studied. These probes, along with a classical probe using a N-methyl-anthranilate fluorophore, are used to take advantage of the ability of siderophores to coordinate Fe³⁺ ions which is coupled with the attractive phosphorescence properties of lanthanide ions. The use of lanthanide metals to create an indicator displacement assays is a novel application of these probes for the detection of Fe³⁺ ions. The use of Tb³⁺ ions as the indicator …

Investigation Of Glassy State Molecular Motions In Thermoset Polymers, Jianwei Tu

Dissertations

This dissertation presents the investigation of the glassy state molecular motions in isomeric thermoset epoxies by means of solid-state deuterium (²H) NMR spectroscopy technique. The network structure of crosslinked epoxies was altered through monomer isomerism; specifically, diglycidyl ether of bisphenol A (DGEBA) was cured with isomeric amine curatives, i.e., the meta-substituted diaminodiphenylsulfone (33DDS) and para-substituted diaminodiphenylsulfone (44DDS). The use of structural isomerism provided a path way for altering macroscopic material properties while maintaining identical chemical composition within the crosslinked networks.

The effects of structural isomerism on the glassy state molecular motions were studied using solid-state ²H …

Computational And Experimental Investigation Into Yield Behavior And Cure Rate Dependence Of Thermoset Polymers, Christopher Harold Childers

Dissertations

This dissertation is broken down into two primary sections: firstly, the development and improvement of molecular dynamics simulations of thermoset matrix polymers including their use in understanding molecular response to applied strain deformation and secondly, the discernment of a cure heating ramp rate dependence of the final molecular and macro-molecular properties of thermoset matrix polymer.

The molecular dynamics section will discuss the development of molecular dynamics simulations of thermoset epoxy/amine matrix polymers, and the implementation of this work to determine the underlying molecular level events that cause thermoset matrix polymer yield. It will report a novel method for the determination …

Ranking Methods For Global Optimization Of Molecular Structures, John Norman Mcmeen Jr

Electronic Theses and Dissertations

This work presents heuristics for searching large sets of molecular structures for low-energy, stable systems. The goal is to find the globally optimal structures in less time or by consuming less computational resources. The strategies intermittently evaluate and rank structures during molecular dynamics optimizations, culling possible weaker solutions from evaluations earlier, leaving better solutions to receive more simulation time. Although some imprecision was introduced from not allowing all structures to fully optimize before ranking, the strategies identify metrics that can be used to make these searches more efficient when computational resources are limited.

Biomarker Discovery Of Liver Diseases Using Mass Spectrometry-Based Metabolomics., Xue Shi

Electronic Theses and Dissertations

Metabolomics has emerged as one of the latest of the "-omics" disciplines that can detect metabolite biomarkers in biological samples. The diverse characteristics of metabolites make the analytical platform challenging in metabolomics. Two bioanalytical platforms were developed in this study to investigate metabolite abundance changes under different biological conditions. We first developed a bioanalytical platform that coupled linear trap quadruple - Fourier transform ion cyclotron mass spectrometer (LTQ-FTICR MS) with direct infusion chip-based nano-electrospray ionization (DI-nESI) and applied it to study polychlorinated biphenyls (PCB) effects on non-alcoholic fatty liver disease (NAFLD). We also employed this platform in conjunction with in …

Oxidative Damage To Dna 2´-Deoxyribose By Carbonate Radicals: Reaction Mechanisms And Products, Terence J. Moore

Electronic Theses and Dissertations

The carbonate radical anion (CO₃^•-, CR) is an important reactive oxygen species produced in vivo by one-electron oxidation of CO₂ or bicarbonate, constituents of the major physiological buffer. It was demonstrated for the first time by using an HPLC-based analysis of low-molecular products of DNA damage that CRs react with DNA 2΄-deoxyribose by the hydrogen abstraction mechanism. CRs exhibit a ~ 800-fold preference for one-electron oxidation of guanine over hydrogen abstraction from DNA sugar, in sharp contrast with •OH. CRs also have, as compared to •OH, an increased preference for the H1΄ abstraction, which is the …

Empirical Demonstration Of Environmental Sensing In Catalytic Rna: Evolution Of Interpretive Behavior At The Origins Of Life, Niles Lehman, Tess Bernhard, Brian C. Larson, Andrew J.N. Robinson, Christopher C.B. Southgate

Chemistry Faculty Publications and Presentations

Background: The origins of life on the Earth required chemical entities to interact with their environments in ways that could respond to natural selection. The concept of interpretation, where biotic entities use signs in their environment as proxy for the existence of other items of selective value in their environment, has been proposed on theoretical grounds to be relevant to the origins and early evolution of life. However this concept has not been demonstrated empirically.

Results: Here, we present data that certain catalytic RNA sequences have properties that would enable interpretation of divalent cation levels in their environment. …

Aminooxy Reagents In Nanomedicine And Bioanalysis., Stephanie Mattingly

Electronic Theses and Dissertations

The development of nanomaterials as medical diagnostic and therapeutic agents is a rapidly expanding field. A brief search of the literature revealed that roughly half of all articles related to nanoparticle-based drug delivery were published after the onset of this thesis research, over the past 4 years. A few nano-based formulations have entered into clinical use, including liposomal drug formulations, protein-linked drugs, and nanoparticle-based MRI contrast agents. The chemistry that enables conjugation of a functional cargo, whether a drug, a targeting element, or a radionucleotide, to a nanocarrier is thus a critical component for development. Oximation is one of the …

Triggered Release Of Small Molecules From Solid Supports Using Heat Or An Applied Magnetic Field., Ralph Jacob Knipp

Electronic Theses and Dissertations

The reaction of an aminooxy moiety (RONH2) with an aldehyde or ketone carbonyl, an oximation reaction, results in the formation of robust oxime ether linkages. Oximation is a form of click chemistry and is chemoselective, occurs in a variety of solvents including water, and produces high yields with little to no purification. We were inspired to exploit the advantages of oximation reactions by attaching aminooxy-functionalized molecules to solid supports, thus allowing us to employ aminooxy chemistry in ways that cannot be achieved using solution phase. Chapter 1 provides a review of aminooxy chemistry, its advantages over similar reactions and its …

Method Development For The Analysis Of Aluminum, Calcium, Magnesium And Iron In Sedimentary Rocks, Zainab Ali Alhawdar

Electronic Theses & Dissertations

The focus of this study involved the analysis of sedimentary rocks by using atomic absorption spectroscopy. There are three classifications of sedimentary rocks: organic, formed as a result of vital activity of organisms such as coal; non-organic (chemical), formed in the process of evaporation of concentrated mineral solution such as limestone, dolomite, gypsum, salt and chert; and clastic (fragmental), formed from pre-existing rocks as a result of their fragmentation followed by further hardening and cementing such as conglomerate, breccia, sandstone, siltstone and shale. There are various analytical methods for analyzing sedimentary rocks, all of which require dissolving and digestion of …

Keeping In Touch: Exchange As An Adaptive Strategy In Southern Nevada, Timothy Joshua Ferguson

UNLV Theses, Dissertations, Professional Papers, and Capstones

Archaeologists have always wondered about the extent of vessel movement in the American Southwest. Identifying vessel movement allows for the study of social interactions across a region and the role of ceramics in the adaptive processes of agriculturalists living in marginal, highly variable environments. In many instances, exchange may act as a way to reduce the risk of resource shortfalls by creating social ties in other areas. This research investigated the changing risk reduction strategies of households in the lowland Virgin region of southern Nevada by using geochemical methods to trace the exchange of locally produced pottery. It was hypothesized …

Firm-Level Productivity Spillovers In China’S Chemical Industry: A Spatial Hausman-Taylor Approach, Peter H. Egger, Badi H. Baltagi, Michaela Kesina

Center for Policy Research

This paper assesses the role of intra-sectoral spillovers in total factor productivity across Chinese producers in the chemical industry. We use a rich panel data-set of 12,552 firms observed over the period 2004-2006 and model output by the firm as a function of skilled and unskilled labor, capital, materials, and total factor productivity, which is broadly defined. The latter is a composite of observable factors such as export market participation, foreign as well as public ownership, the extent of accumulated intangible assets, and unobservable total factor productivity. Despite the richness of our data-set, it suffers from the lack of time …

Speciation Of Pentavalent Technetium Complexes With Aniline And Thiobenzene Derivatives, Kyle E. Childs

UNLV Theses, Dissertations, Professional Papers, and Capstones

The reaction of bidentate aniline oligomers with pentavalent technetium has been investigated previously through the reaction of (n-Bu4N)TcOCl4 with o-phenylenediamine (PDA). The initial studies found that PDA reacted in a 1 to 2 molar ratio with pentavalent technetium in in ethanol. This study was expanded by the examination of a second aniline derivatives, 2-aminophenol (AMP)) and two thiobenzene derivatives (2-mercaptophenol (MP) and thiosalicylic acid (TSA)) to evaluate the kinetic formation of these complexes with pentavalent technetium. The pentavalent technetium complexes all showed reactivity with technetium having a coordination numbers of 5 with all ligands reacting in a 1 to 2 …

Simultaneous Determination Of Multiple Actinide Elements In A Variety Of Soils Utilizing A Standardized Sequential Extraction Protocol, Sherry Alina Faye

UNLV Theses, Dissertations, Professional Papers, and Capstones

To obtain a better understanding of the mobility of actinide element contaminants in the environment, the association of the contaminants with specific host phases of soils and sediments must be investigated. This investigation is most commonly conducted using sequential extraction techniques that employ the selective dissolution of soil phases with increasingly aggressive chemical treatment. Though several sequential extraction studies exist in literature, conclusions cannot be made by direct comparison of data due to the lack of uniformity in the protocols used. This work aims to continue development of a standard sequential extraction protocol and expanding its capabilities to include the …

Technetium Sulfide: Fundamental Chemistry For Waste Storage Form's Application, Maryline Ghislaine Ferrier

UNLV Theses, Dissertations, Professional Papers, and Capstones

Technetium is the lightest radioelement. The isotope ⁹⁹Tc has around a 6% yield from ²³⁵U with a half-life of 2.13 x 10⁵ years. The high mobility of TcO₄^-, the common chemical form of technetium in the environment makes ⁹⁹Tc an isotope of concern in nuclear waste management. Despite its important role in radiopharmaceuticals and in the nuclear fuel cycle, the fundamental chemistry of technetium is not as well developed as that of the neighboring transition metals; one of the most striking examples being its sulfide chemistry.

Only two technetium binary sulfide compounds had …

Spectroscopic Investigation Of The Chemical And Electronic Properties Of Chalcogenide Materials For Thin-Film Optoelectronic Devices, Kimberly Horsley

UNLV Theses, Dissertations, Professional Papers, and Capstones

Chalcogen-based materials are at the forefront of technologies for sustainable energy production. This progress has come only from decades of research, and further investigation is needed to continue improvement of these materials.

For this dissertation, a number of chalcogenide systems were studied, which have applications in optoelectronic devices, such as LEDs and Photovoltaics. The systems studied include Cu(In,Ga)Se2 (CIGSe) and CuInSe2 (CISe) thin-film absorbers, CdTe-based photovoltaic structures, and CdTe-ZnO nanocomposite materials. For each project, a sample set was prepared through collaboration with outside institutions, and a suite of spectroscopy techniques was employed to answer specific questions about the system. These …