Chemistry Commons^™

Synthesis And Characterization Of Synthetic Urban Melt Glass, Rebecca Kristien Lowe

UNLV Theses, Dissertations, Professional Papers, and Capstones

Melt glass formed from the explosion of a nuclear device is a unique post-detonation material that can aid in the ensuing forensics investigation. Trapped in the melt glass are chemical and isotopic signatures that can provide diagnostic and source information about the weapon by comparison with documentation of previous detonations. A nuclear terrorist attack would likely take place in an urban environment and as such, the melt glass formed would consist of a complex matrix including urban materials like cement and glass, activation products from the large neutron flux that will be seen, and fission products from the detonation. The …

Characterization Of Beryllium Ion Complexation In The Presence Of Biological Buffers Using Isothermal Titration Calorimetry, Guillermo Alexander Ramirez

UNLV Theses, Dissertations, Professional Papers, and Capstones

Be2+ ion is a biologically active metal that is capable of binding to proteins and has been shown to affect various cellular processes. When treated with Be2+, certain cancer cells display cytostatic effects. GSK3β is a regulatory kinase involved in the β-catenin pathway that may be involved in producing these cytostatic effects when Be2+ binds to it. In order to determine binding parameters between Be2+ and GSK3β, isothermal titration calorimetry (ITC) can be utilized. However, titrations at physiological pH cannot be carried out due to Be2+ unique speciation at neutral pH ranges. Significant precipitation occurs at pH 6 and higher …

Investigations Of Technetium Metal And The Synthesis Of Binary Technetium Nitrides Under Extreme Conditions, Emily Siska

UNLV Theses, Dissertations, Professional Papers, and Capstones

Technetium (Tc) is the lightest of the radioactive elements and has no stable isotopes. Significant quantities of Tc are not naturally occurring on earth. However, technetium is found in high fission yield in nuclear reactors and produced for medical imaging. With its long half life, and high mobility in the environment make it of particular interest. To that end, the fundamental chemistry of Tc and Tc compounds is not as well understood compared to neighboring elements on the periodic table. Therefore, fundamental studies designed to better understand this transition metal, coupled with more targeted investigation at high temperature and pressure …

Geochemical Tracers Of Arctic Ocean Processes: A Study Of Gallium, Barium, And Vanadium, Laura M. Whitmore

Dissertations

The Arctic Ocean is linked to the global oceans and climate through its connectivity with the North Atlantic Ocean and the regional thermohaline deep water formation sites. It’s also a region undergoing rapid environmental change. To inform the community of potential changes in geochemical and biogeochemical cycles, this dissertation addresses three dissolved geochemical tracers (gallium, barium, and vanadium) as indicators of Arctic Ocean processes. Gallium is tested as a replacement for nutrient-type tracers in an effort to deconvolve Pacific and Atlantic derived waters in the Arctic Ocean basins. These water masses carry different heat and salt content and can influence …

Hot Electron Chemistry On Bimetallic Plasmonic Nanoparticles, Bryn E. Merrill, Bingjie Zhang, Jerry Larue

Student Scholar Symposium Abstracts and Posters

Catalysis provides pathways for efficient and selective chemical reactions through the lowering of energy barriers for desired products. Gold nanoparticles (AuNP) show excellent promise as plasmonic catalysts. Localized surface plasmon resonances are oscillations of the electron bath at the surface of a nanoparticle that generate energetically intense electric fields and rapidly decay into energetically excited electrons. The excited electrons have the potential to destabilize strongly bound oxygen atoms through occupation of accessible anti-bonding orbitals. Tuning the anti-bonding orbitals to make them accessible for occupancy will be achieved by coating the AuNP in a thin layer of another transition metal, such …

Molecular Dynamics Simulations Of Apolipoprotein A1 In Ionic Liquids, Benjamin Smith

Honors Theses

High-density lipoprotein function is essential for the healthy processing of fats in the blood. The function of these proteins is determined by their conformational structure of chains of amino acids. Certain ionic liquids have been shown to interact with individual amino acids to affect the tertiary shape of the protein. These interactions can disrupt the native hydrogen bonds between amino acids which can either promote folding or denaturing of the protein. Our work focused on apoA-1, a high-density lipoprotein that binds to cholesterol for efflux from the body. We studied this protein in different ion-based liquids with sodium, chloride, and …

Gold Nanoparticles: Core Conversion Of Au144(Sch2ch2ph)60 To Au99(Sph-Ch3)42 Using Aromatic Thiolate Ligands And Crystallization Of Au99(Sph-Ch3)42, Elizabeth Turnage

Honors Theses

The purpose of this thesis is to synthesize Au₁₄₄(SCH₂CH₂Ph)₆₀ using a two-step synthesis reaction, and then using this product to conduct a core conversion from Au₁₄₄(SCH₂CH₂Ph)₆₀ to Au₉₉(SPh-CH₃)₄₂. The Au₉₉(SPh-CH₃)₄₂ product will then be used to attempt to form crystals using five different crystal set-up methods. Au₁₄₄(SCH₂CH₂Ph)₆₀ is made with aliphatic thiolate ligands, and when it is placed in a mixture containing excess para-methyl benzenethiol, it undergoes a …

Identification And Quantification Of Classic, Prescription, And Synthetic Opioids In Hair By Liquid Chromatography Tandem Mass Spectrometry (Lc/Ms/Ms), Natalia A. Platosz

Student Theses

The current use and misuse of synthetic and prescription opioids in the US has reached epidemic status. According to the US Department of Health and Human Services, every day more than 130 people in the US die after overdosing on opioids, and 2.1 million had an opioid use disorder in 2016. Hair is becoming an alternative matrix of increasing interest in forensic toxicology to investigate drug use and abuse patterns due to its long window of detection. The focus of this project was to develop and validate a method that simultaneously detects and quantifies 27 classic, prescription and synthetic opioids …

Toxicity Analysis Of 2’-Deoxyguanosine-N2-6-Aminopyrene And 2’-Deoxyguanosine-N2-8-Aminopyrene In Escherichia Coli, Emily Janeiro

Honors Scholar Theses

Cancer is a disease that stems from genomic errors that are not corrected properly by cellular repair mechanisms. Errors are more likely to form when organisms are subjected to DNA damage by mutagenic compounds. 1-Nitropyrene, a nitrated polycyclic aromatic hydrocarbon (nitro-PAH), has been shown to be a potent mutagen that causes cancer. Nitro-PAHs can arise from diesel exhaust products in the environment. Out of all nitro-PAHs, 1-nitropyrene is found in largest quantities in the environment. This poses a great need to study its effects biochemically in order to address its toxicity in DNA. Other nitropyrene derivatives, including 1,6-dinitropyrene and 1,8-dinitropyrene, …

Elucidating The Binding Pockect Of The Gpr119 Receptor, A Type 2 Diabetes Target, Matthew Dy Rosales

Theses and Dissertations

An in-house homology model of the GPR119 receptor was used to identify residues which may affect ligand binding and ligand-dependent activity through computational and experimental studies. In a docking study comparing an agonist and its inverse agonist structural analog, Leu5.43169, L6.52242 and Ser1.324 appear to be involved in ligand binding. These residues were mutated experimentally to test the predictions of the homology model. The in vitro studies indicate that Leu5.43169 and Ser1.324 mutations cause ten-fold and six-fold decreases in ligand-induced cAMP formation, indicating their importance in ligand-induced activation. Leu6.52242 mutations show minimal effect in cAMP production, indicating a lesser involvement …

Mesoporous Adsorbents For Perfluorinated Compounds, Bertha Lotsi

Electronic Theses and Dissertations

Effective adsorbents for polyfluorinated compounds (PFCs) were successfully prepared. And they were tested in the adsorption of perfluorooctanoic and perfluorooctanesulfonic acids. Bridged silsesquioxanes containing secondary and tertiary amino groups were synthesized by sol-gel condensation of bis[3-(trimethoxysilyl)propyl]amine and bis[3-(methylamino)propyl]-trimethoxysilane in acidic media with surfactants. Obtained materials are mesoporous with a high BET surface area. They combine high structural stability with a high concentration of surface amino groups serving as adsorption sites. Batch adsorption tests demonstrated their extremely high adsorption capacity on PFCs: in some experiments, it reached up to 88% of the adsorbent weight. Adsorption of PFCs changed the surfaces of …

Computational Quantum Study Of Intermediates Formed During The Partial Oxidation Of Melatonin, Oladun Oladiran

Electronic Theses and Dissertations

Melatonin is a neurohormone produced by the pineal gland in the brain. It functions as an antioxidant to scavenge free radicals. Free radicals are reactive species; they often oxidize the cells leading to oxidative stress which may lead to severe health complications. Reaction of melatonin with free radicals is known to be stepwise, as such the stability of the intermediates can be examined. Thus, the possibility of using melatonin as an in vivo spin trap can be determined. Spin traps allow characterization of unstable radical species using electron spin resonance spectroscopy. In this research, ab initio quantum chemistry techniques were …

Photocatalytic Carbon Dioxide Reduction With Zinc(Ii) Dipyrrin Photosensitizers And Iron Catalyst, Senan Rasheed

Electronic Theses and Dissertations

Much of the energy used in the United States and around the globe is obtained from petroleum, natural gas, and coal. Photocatalytic CO₂ reduction can be used to transform CO₂ to useful fuels and making fossil fuels more renewable. Input of energy is required, and the sun can provide the required energy for this transformation. Photosensitizer, catalyst, and electron donor are required for photocatalytic CO₂ reduction.

Due to lack of earth-abundant sensitizers, zinc dipyrrin complexes were synthesized by previous group members and have been used as photosensitizers in this research. The ground and excited state electrochemical properties …

Immobilization Of Phosphotungstic Acid On Silica Surface For Catalytic Alkylation Of Aromatic Compounds, Anastasia Kuvayskaya

Electronic Theses and Dissertations

Superacidic mesoporous materials containing covalently embedded PTA were synthesized by sol-gel method. Tetraethyl orthosilicate (TEOS) and phosphotungstic acid (PTA) were used as precursors in the synthesis, ionic and nonionic surfactants were used as pore-forming agents, the reaction proceeded in acidic media. TEM images revealed mesoporous structure with embedded PTA clusters. FT-IR spectra of obtained materials contained characteristic bands of PTA at 957 cm-1. Synthesized catalysts had high BET surface area and high concentration of acidic sites. Alkylation of 1,3,5-trimethylbenzene by 1-decene demonstrated high catalytic activity. The catalyst obtained with Pluronic P123 as a template was the most effective and resulted …

Addressing Diversity And Inclusion Through Group Comparisons: A Primer On Measurement Invariance Testing, Guizella A. Rocabado, Regis Komperda, Jennifer E. Lewis, Jack Barbera

Chemistry Faculty Publications and Presentations

As the field of chemistry education moves toward greater inclusion and increased participation by underrepresented minorities, standards for investigating the differential impacts and outcomes of learning environments have to be considered. While quantitative methods may not be capable of generating the in-depth nuances of qualitative methods, they can provide meaningful insights when applied at the group level. Thus, when we conduct quantitative studies in which we aim to learn about the similarities or differences of groups within the same learning environment, we must raise our standards of measurement and safeguard against threats to the validity of inferences that might favor …

X-Panding Halogen Bonding Interactions: Hybrid Cocrystals Composed Of Ionic Halides, Iodine And Organoiodines, Khadijatul Kobra

All Dissertations

Halogen bonding referred to as an attractive, noncovalent interaction between an electrophilic region of a halogen atom X (acts as Lewis acid) and a nucleophilic region of a molecule Y (acts as Lewis base). Such interactions and the resulting polymeric networks play an important role in many fields related to crystal engineering, including for example, the fabrication of liquid crystals and novel drug design. The application of halogen bonding has particular promise in biological systems by increasing the lipophilicity of drugs to improve penetration through lipid membranes and tissues, enabling better intracellular delivery.

Based on this concept, my research at …

The Synthesis Of Urethane Acrylate Resin From Palm Fatty Acid Distillate And Some Mechanical Properties, Kim Teck Teo

Student Works (2020-2029)

Depletion of petroleum reserves and increasing environmental concerns have stimulated the efforts to explore materials from readily available, renewable natural resources, such as carbohydrates, oils, fats and proteins. Plant oil and its fatty acids are promising renewable resources to produce environmentally friendly polymeric materials. Palm oil is a major crop in Malaysia and consequently palm fatty acid distillate (PFAD) has been an abundant by-product during the refinery process. PFAD could be a renewable raw material for industrial application. Thus, we develop new PFAD-based acrylate resins UV curable for coatings applications. The resins could be produced by two approaches. Firstly, mixtures …

Exploring Pyrochlore Host For Upconversion And Downconversion Luminescence Materials, Mitzy A. Penilla Garcia

Theses and Dissertations

Pyrochlore has been the focal point of research in materials science community in the area of nuclear waste host, thermal barrier coatings, solid oxide fuel cell, catalyst, magnetism, luminescence etc. Such application arises due to their unique properties such as wide band gap, high radiation stability, low thermal conductivity, high dialectic constant. The fact it also has high structural ability, low phono energy and ability to accommodate dopant ion at both A- site and B-site; they are considered excellent host for inorganic phosphors. Here research work is directed towards synthesizing optical materials having high quantum efficiency for down-conversion (DC) and …

Effect Of Charged Lipids On The Ionization Behavior Of Glutamic Acid Containing Transmembrane Helices, Brooke Nunn

Chemistry & Biochemistry Undergraduate Honors Theses

Transmembrane proteins make up critical components of living cells. Protein function can be greatly impacted by the charged state of its respective components, the side chains of amino acid residues. Thus far, in the lipid membrane, little is known about the properties of residues such as glutamic acid. To explore these properties, I have included glutamic acid in a suitable model peptide-lipid system for fundamental biophysical experiments. Within the system, I have placed a glutamic acid residue instead of leucine in the L14 position of the helical hydrophobic peptide GWALP23 (acetyl-GGALWLALALALAL¹⁴ALALWLAGA-amide). Substitutions of glutamine and aspartic acid serve …

Computational Study Of Novel Fxbn Spin Trap Analogs With Hydroxyl Radicals, Alexis Harvey

Undergraduate Honors Theses

Free radicals are reactive molecules, which makes them difficult to study. Learning more about free radicals is necessary since they are implicated in many diseases and conditions such as Alzheimer’s disease and aging. Spin traps are molecules that can be used to stabilize free radicals to allow time for the free radicals to be characterized. The purpose of this research was to examine four novel spin traps that combine the properties of existing spin traps to possibly create more effective spin traps. The four novel molecules in question were designed by taking the 4-methylfuroxanyl ring from the α(Z)-(3-methylfuroxan-4-yl)-N-t-butylnitrone spin trap …

Heteroatom-Doped Chemical Vapor Deposition Carbon Ultramicroelectrodes, Alexis Sanwick

Undergraduate Honors Theses

Metal nanoparticles have been a primary focus in areas of catalysis and electrocatalysis applications as a result of their large surface area-to-volume ratios. While there is an increased interest in understanding the properties and behaviors of metal nanoparticles, they can become expensive over time. Recent research has incorporated the idea of using heteroatom-doped materials as a cheaper catalytic alternative to metal nanoparticles. In this study nitrogen-doping and phosphorous-doping techniques were applied to chemical vapor-deposited carbon ultramicroelectrodes in order to study the electrocatalytic properties toward the oxygen reduction reaction and the enhanced affinity for the deposition of gold nanoparticles onto the …

Raman Spectroscopic And Quantum Chemical Investigation Of The Effects Of Tri-Methylamine N-Oxide (Tmao) On Hydrated Urea, Hydrated Guanidinium, And Hydrogen Bonded Networks, Genevieve Verville

Honors Theses

Trimethylamine N-Oxide (TMAO), guanidinium, and urea are three important

osmolytes with their main significance to the biophysical field being in how they

uniquely interact with proteins. TMAO is known to stabilize and counteract the

destabilizing effects of both urea and guanidinium. The exact mechanisms by which

TMAO stabilizes and both guanidinium and urea destabilize folded proteins continue

to be debated in the literature. Some studies suggest that solvent interactions do not

play a large role in TMAO’s stabilizing effects and therefore advocate direct

stabilization, whereas others suggest that TMAO counteracts denaturation primarily

through an indirect effect of strong solvent interactions. …

The Photon Absorber And Interconnecting Layers In Multijunction Organic Solar Cell, Brishty Deb Chowdhury, Bernabe Ibarra, Federico Cesano, Yuanbing Mao, Muhammad N. Huda, Aminur Rashid Chowdhury, Carolina Olivares, M. Jasim Uddin

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Organic photovoltaic devices have long been considered as an important alternative for coal-based energy technologies due to their low-cost, lightweight and flexible nature. However, the power conversion efficiencies of such cells are limited by thermalization and transmission losses, which can be overcome by stacking multiple cells in a tandem configuration. This approach allows utilization of the wider spectrum of solar light, helping in attaining the theoretical limits for single cell efficiency (~30%). However, the performance of such tandem organic solar cells depends largely on several factors, including the proper design of absorber, sub-cells and interconnecting layer materials. In this review, …

Synthesis Of Amide And Sulfonamides As Pde11 Inhibitors, Noor Abouchakra

Theses, Dissertations and Culminating Projects

With increasing age, individuals begin to experience cognitive decline, especially memory deficits. Given the lack of effective treatments for memory loss, a new promising approach includes targeting second messenger systems that play a critical role in cognitive processes by inhibiting phosphodiesterases (PDEs), specifically PDE11A since its expression is restricted to the brain. PDE11A is responsible for regulating levels of second messengers, such as cyclic AMP and cyclic GMP, which participate in several biochemical processes relating to long term memory function. Since these signaling cascades are controlled by PDEs that result in turning off the signaling pathway, inhibiting phosphodiesterases will lead …

The Ability Of Vitreous Metabolite Concentration To Determine Time Of Death, Victoria Wiggins

Themis: Research Journal of Justice Studies and Forensic Science

This paper analyzes the ability of vitreous fluid to determine time of death. The high variability in current methods used to establish post-mortem interval (PMI), or the amount of time between death and post-mortem examination make it difficult to obtain an accurate estimation. The concentration of metabolites found within vitreous fluid, such as potassium (K+), hypoxanthine (Hx), and magnesium (Mg), are the most researched alternatives to traditional methods in PMI determination because of the relative isolation of vitreous within the body and its ability to withstand degradation. There is no clear consensus on which metabolite provides the most accurate data …

Dose Response Effect Of Mycobacterium Smegmatis-Derived Lipomannan In Raw 264.7 Murine Macrophages, Cassandra Robertson

Undergraduate Theses and Capstone Projects

Tuberculosis is a debilitating respiratory disease caused by the bacterial species Mycobacterium tuberculosis, which acts by infecting the host’s macrophages and evading their immune responses. The purpose of the study was to determine if RAW 264.7 murine macrophage activity could be facilitated and intensified by stimulation with LAM from M. smegmatis. Stimulation with bacterial LAM, and lipopolysaccharide (LPS) as a positive control, yields functional endpoints: nitric oxide (NO) production measured by nitrites (NO2) in the culture supernatant and expression of proteins, such as tumor necrosis factor-α and inducible nitric oxide synthase (iNOS). RAW 264.7 cells were stimulated dose-responsively with LAM …

Development Of Capillary-Channeled Polymer (C-Cp) Fiber As Stationary Phase For Biological Sample Application, Lei Wang

All Dissertations

Capillary-channeled polymer (C-CP) fibers as an alternative support/stationary phase for biomacromolecule separations on analytical and preparative scales have been developed by Marcus research group. The combination of the fiber micro- and macro-structures and in-column orientation allows operation at comparably high linear velocities (~100 mm s-1) without excessive system backpressure. The ability to move fluid efficiently through the structure is complemented by the fact that the fiber physical structure is effectively nonporous with respect to the size of proteins, therefor there is no significant intrafiber diffusion. Ultimately, these factors combine for protein separations that are devoid of appreciable van Deemter C-term …

Materials Design For High-Performance Organic Redox Flow Batteries And Electrocatalytic Carbon Dioxide And Nitrogen Reduction, Bo Hu

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Nowadays, the utilization of renewable energy resources such as solar and wind energy has been realized to be a sustainable and environmentally benign strategy to alleviate the world’s severe dependency on traditional fossil fuels, and thus enables the environmental recovery and sustainable development of the economy. The massive commercialization of solar and wind energy raises the demands for advanced energy storage technologies, among which the redox flow battery has been recognized as a promising solution due to it is low cost, safe, environmentally benign, and easy to be scaled up. All vanadium redox flow battery stands for the most important …

Resolution Of Portable Raman Spectrometers And Its Effect On The Analysis Of Biological Specimens, Jalissa Thomas

Chemistry

Body fluid traces are a common and a major form of evidence that can be found at a crime scene, as it is a good source of DNA. As such, it is vital that body fluid evidence is properly detected and identified. Issues with the current methods of identifying body fluids and the large backlog of evidence in most forensic labs call for more accurate on-scene (in situ) body fluid identification. Past research has demonstrated that Raman spectroscopy is an advantageous tool for accurately and quickly identifying body fluids, namely in the laboratory. Portable Raman instruments have been …

Surface-Enhanced Raman Spectroscopy For Cocaine Detection, Kiersten Jo Mead

Chemistry

The detection of drugs of abuse using Raman spectroscopy is of particular interest to forensic researchers at the moment. Raman spectroscopy is highly specific, fast, non-destructive, and can be adapted for in-situ measurements, making it the ideal forensic technique. Researchers working under the guidance of Doctor Igor Lednev have been able to use UV resonance Raman spectroscopy to detect cocaine in oral fluid without the need for sample pretreatment. They were however unable to detect the cocaine at forensically relevant levels. To overcome this limitation, surface-enhanced Raman spectroscopy (SERS) was used in this proof of concept study for the detection …