Chemistry Commons^™

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 …

Comparison Of Three Analytical Techniques For General Characterisation Of Selected Algae And Cyanobacteria, Mohamed Iqbal Suhaina Nashath

Student Works (2020-2029)

Algae and cyanobacteria maintain the oxygenation of earth, and are utilised as biofuels, biofertilizers and nutrition feed. The characterisation of algae and cyanobacteria through conventional methods require technical expertise, laborious sample preparation, and moderately expensive instruments and reagents. Hence, in this study, selected bioanalytical techniques with minimal sample preparation were incorporated, to simplify the characterisation of algae and cyanobacteria. The objectives of this research were to study the phylogenetic relationship of the selected algae and cyanobacteria via the 23S plastid ribosomal ribonucleic acid (rRNA) and 18S rRNA biomarkers; to validate the presence of the microcystin synthetase (mcy) gene cluster encoding …

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 …

Functional Nanomaterials By Combining Aminooxy Chemistry And Iodine Activation At Momolayer Protected Clusters., Tirtha Raj Sibakoti

Electronic Theses and Dissertations

Aminooxy (-ONH₂) groups are most commonly known for their chemoselective reaction with carbonyl compounds (aldehydes/ketones) under mild reaction conditions. Aminooxy-based click chemistry is a versatile means of ligation as evidenced by broad application in material science, biology, biochemistry, analytical chemistry, and nanoscience. Our work exploits the facile reaction of aminooxy groups presented on the surface of gold (Au) or palladium (Pd) monolayer protected clusters (MPCs) with various aldehydes via oximation reactions, which form the robust oxime ether adducts. The functionalization of hexanethiolate-stabilized Au MPCs with a newly developed trifunctional amine-containing aminooxy alkanethiol ligand by thiol place-exchange affords aminooxylated …

Determining Particle Size Of Polymeric Micelles In Thermothickening Aqueous Solutions, Jessica Diane Bruer

Graduate Theses/Dissertations

Many active pharmaceutical ingredients (APIs) are poorly soluble and cause inadequate drug absorption. Soluplus^®, a polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer, is a commercial excipient (BASF Corp) that enhances the solubility and bioavailability of many APIs. The mechanism of enhancement is related to the ability to form polymeric micelles in solution. These micelles store insoluble APIs in their hydrophobic interior and transport them to targeted sites in the body. An important characteristic of solubility enhancers is the particle size exhibited in solution before and after loading with APIs. This is most commonly determined by dynamic light scattering (DLS) …

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 …

Analysis Of Fatty Acids In Chukchi Sea Sediments, Damilola Ajadi

Theses and Dissertations

The Arctic Ocean and its marginal seas are key areas for understanding the global climate system. Climate change causes increased terrigenous materials to be carried into the ocean as well as higher production of marine organic matter in the ocean. This study determined the concentrations, distribution, and sources of fatty acids in core sediments from four locations: Stations H32, H30, BarC5 and H24 in the Chukchi Sea, which are in the Arctic Ocean. Fatty acids are valuable tracers of marine or terrigenous inputs and may give evidence to the extent of climate change. Fatty acids were analyzed, characterized using GC-MS …

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 …

Green Synthesis Of Reduced Graphene Oxide For Efficient Adsorption-Photocatalysis Studies In Methylene Blue Dye Degradation, Ling Er Valerie Siong

Student Works (2020-2029)

Dyes are one of the major components of industrial effluents. Owing to the complex structures of these toxic organic compounds, the removal of dyes from effluents possesses a great challenge in wastewater treatment. In order to tackle this issue, one of the effective methods is to remove dyes via the combination of adsorption and photocatalysis processes. In the present work, reduced graphene oxide (rGO) was fabricated from graphene oxide (GO) by using an environmentally friendly solvothermal approach, whereby ethanol was employed as a non-toxic reductant. In order to investigate the formation of rGO, the reduction of GO was carried out …

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, …

Understanding Ice Mixtures Under Pluto Simulated Conditions And Their Implications For Geophysical Processes, Caitlin Joannah Ahrens

Graduate Theses and Dissertations

New Horizons at Pluto has given the planetary science community the first images of Pluto’s surface, including geologic wonders and compositional variability. Methane, nitrogen, and carbon monoxide make up the bulk of the volatile plutonian surface along with water ice. In this work, these three main volatiles are specifically investigated in the laboratory setting to understand the spectral properties and behavior of binary and ternary mixtures. The spectra are taken in the near-infrared wavelengths (1 – 2.5 µm) using Fourier transform infrared (FTIR) spectroscopy techniques utilizing the Pluto Simulation Chamber housed at the University of Arkansas, which can reach conditions …

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 …

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 …

Chemical And Electronic Surface Structure Of Chalcopyrite-Based Thin Films For Solar Water Splitting, James C. Carter

UNLV Theses, Dissertations, Professional Papers, and Capstones

In recent years, various thin film solar devices have reached markedly high efficiencies on both the laboratory and large area scale. To further evaluate their potential, and help drive device optimization of efficient solar devices, a detailed understanding of the chemical and electronic structure of the surfaces and interfaces is required. It is these interfaces that play a pivotal role in dictating aspects of device performance. Chalcopyrite-based materials, such as Cu(In,Ga)S2 (CIGS) are regarded as one of the most promising absorber materials for use in highly efficient solar devices. In the context of photoelectrochemical (PEC) hydrogen generation, the tunability of …

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 …

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 …

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 …

Richardsite, Zn2cugas4, A New Gallium-Essential Member Of The Stannite Group From The Gem Mines Near Merelani, Tanzania, Luca Bindi, John A. Jaszczak

Michigan Tech Publications, Part 1

The new mineral richardsite occurs as overgrowths of small (50–400 μm) dark gray, disphenoidal crystals with no evident twinning, but epitaxically oriented on wurtzite–sphalerite crystals from the gem mines near Merelani, Lelatema Mountains, Simanjiro District, Manyara Region, Tanzania. Associated minerals also include graphite, diopside, and Ge,Ga-rich wurtzite. It is brittle, dark gray in color, and has a metallic luster. It appears dark bluish gray in reflected plane-polarized light, and is moderately bireflectant. It is distinctly anisotropic with violet to light-blue rotation tints with crossed polarizers. Reflectance percentages for Rmin and Rmax in air at the respective wavelengths are 23.5, 25.0 …

Spectroscopic And Computational Studies Of The Agricultural Active Ingredient Dicamba, James Johnson

Honors Theses

3,6-dichloro-2-methoxy benzoic acid, more commonly known as Dicamba, is the active ingredient in an array of pesticides used on farmlands across the globe. Dicamba’s mode of action works by mimicking the plant hormone auxin, which is synonymous to growth hormones in mammals. The mimicking of auxin results in excessive elongation and growing, which is eventually fatal for plants when the rate of growth can no longer be sustained. Dicamba has risen in prominence in recent years due to drift damage as a result of Dicamba’s high volatility. Having the ability to identify Dicamba is crucial for the agricultural industry. The …

Assessing Amino Acid Racemization In Avian Eggshells Through Reverse Phase Liquid Chromatography, Nikitha Nelapudi

Honors Theses

The extent of amino acid racemization (AAR) observed in organic material offers insight into geochronology. Within the scope of AAR research, Avian eggshells are reliable sources of data due to retention of indigenous amino acids through calcification. This project develops a robust quantification methodology for up to 9 D/L amino acids using reverse-phase HPLC (RP-HPLC) with precolumn derivatization. Reliable quantitation is established via statistical assessment of detectability and calibration curves. Progress has focused on obtaining adequate enantioseparation and reproducible data of single D/L amino acids.

Design Of A Novel Isoxazoline Class Drug For The Suppressive Treatment Of Malaria, Peyton Ware

Honors Theses

Design of a novel isoxazoline class drug for the suppressive treatment of erythrocytic malaria through the inhibition of Plasmodium Falciparum Gylceraldehyde-3-phosphate Dehydrogenase (PfGAPDH) gave rise to creation of a synthetic plan for the proposed target molecule α-amino- 3-bromo-4,5-dihydroisoxazol-5-yl propionic acid. A literature-based analysis of the moieties targeting the PfGADPH active site led to the design of the target molecule. Subsequently, an exploration of the literature yielded a possible bifold synthetic plan. Attempts at a model epoxidation reaction using mCPBA and further efforts towards the synthesis of a 3- bromoisoxazoline were shown to be successful using GCMS analysis.

A Game-Theoretic Approach To Deciphering The Dynamics Of Amyloid-Beta Aggregation Along Competing Pathways, Preetam Ghosh, Pratip Rana, Vijayaraghavan Rangachari, Jhinuk Saha, Edward Steen, Ashwin Vaidya

Faculty Publications

Aggregation of amyloid-β (Aβ) peptides is a significant event that underpins Alzheimer's disease (AD). Aβ aggregates, especially the low-molecular weight oligomers, are the primary toxic agents in AD pathogenesis. Therefore, there is increasing interest in understanding their formation and behaviour. In this paper, we use our previously established results on heterotypic interactions between Aβ and fatty acids (FAs) to investigate off-pathway aggregation under the control of FA concentrations to develop a mathematical framework that captures the mechanism. Our framework to define and simulate the competing on- and off-pathways of Aβ aggregation is based on the principles of game theory. Together …

Surface Chemistry And Surface Properties Of Energetic Nitrocellulose (Nc), Henry Grau

Seton Hall University Dissertations and Theses (ETDs)

This research describes an investigation into the wettability of nitrocellulose (NC), most importantly to nitroglycerin (NG), which are key components of formulations used to propel military ammunition. NG demonstrates complete wetting of NC and, overtime, NG sweats on the NC surface and leaks out. The leaking out of NG from the solid formulation is a known cause of fires and explosions resulting from storage. The origin of this research is inspired by the need to engineer a solution to leakage problems of energetic plasticizer in NC based propellant. While searching for a viable material for a specific application, we journeyed …

Optimization Of The Mechanochemical Synthesis Of Several Distinct Compounds., Joseph Ryan Williams

Honors College Theses

Mechanochemical synthesis, as used in this work, is the mechanical milling of reagents to drive reaction. It is often considered a greener alternative to traditional solution-based methods of synthesis. This work will describe the mechanochemical synthesis of furan-2-yl(pyrrolidin-1-yl)methanethione and N-hexadecylfuran-2-carbothioamide, the optimization of the mechanochemical synthesis of 1,3-dibenzylbenzimidazolium bromide as well as the kinetics of this reaction, and finally the ongoing development of the mechanochemical synthesis of N,N′-dioctyl-2,2′-bipyridine-4,4′-dicarboxamide.

This work studied both the traditional method and mechanochemical method for synthesis of furan-2-yl(pyrrolidin-1-yl)methanethione, as well as the mechanochemical method for N-hexadecylfuran-2-carbothioamide. While initial work was promising, it was …