Physical Sciences and Mathematics Commons^™

Preparation And Characterization Of Thermodynamically Controlled Polymer Nanocomposites, Jiadi Hou

Masters Theses

The mechanical and physical properties of polymeric materials can be greatly improved by adding nanoscale additives. To mediate the dispersion of nanoparticles in polymers, it is often necessary to modify their surfaces to prevent aggregation. While polymer nanocomposites system consisting of homopolymer-grafted nanoparticles are well understood, copolymer-functionalized nanoparticles are less well understood but provide additional ways to alter dispersion through the use of chemically different comonomers. In this thesis, polystyrene nanocomposites blended with copolymer-grafted nanoparticles were prepared and studied. The particular comonomers used were methyl methacrylate and cyclohexyl methacrylate, which provides miscibility with polystyrene. Polymers with varying comonomer ratios were …

Rapid Dissolution For Destructive Assay Of Nuclear Melt Glass, Jonathan Allen Gill

Masters Theses

This study evaluates four methods for dissolving complex glassy debris resulting from nuclear detonations. The samples of interest simulate the glassy debris generated from a nuclear detonation’s fireball coming in contact with solid masses. Each method attempts to achieve dissolution through different approaches involving either acid digestion, alkaline digestion, or molten salt fusion. Two of the four methods were modified to retain all elements of the debris or surrogate debris. This retention is critical to the proportional relationships used in identifying fuel types and designs of nuclear weapons. Analysis is conducted with an inductively coupled time of flight mass spectrometer …

Chemical Investigations Of Diabetes Mellitus, Malaria, And Castrate-Resistant Prostate Cancer, Maggie Sparks Lookadoo

Masters Theses

This work studies a variety of molecules and the systems they are involved in to further understand disease and treatment of diabetes mellitus, malaria, and castrate resistant prostate cancer. The first system studied, diabetes mellitus, involves synthesis of 5 different steroidal compounds, while the other two systems, malaria and castrate-resistant prostate cancer, apply mass spectrometric-based untargeted metabolomics to study both known metabolites and unknown spectral features.

Diabetes mellitus is a result of the dysfunction and death of islet beta cells caused by the transcription of pro-inflammatory cytokines resulting in reduced insulin secretion and uncontrollable blood glucose levels. Glucocorticoids can reduce …

Siloxane And Silane-Functionalized Polynorbornenes As Membranes For Passive Carbon Dioxide Separation, Eunice Koheun Hong

Masters Theses

In 2012, carbon dioxide (CO₂) [carbon dioxide] accounted for approximately 82% [percent] of all U.S greenhouse gas emissions.¹ These excessive CO2 levels have been attributed to climate changes that have a range of negative effects on human health and welfare.1 In an effort to decrease these emissions, polymeric membranes consisting of silane- and siloxane-functionalized norbornene units have been targeted as a potential solution for the passive separation of CO2 from other non-greenhouse gases. These substituted norbornene-based polymers were synthesized via vinyl-addition polymerization. Through a series of catalyst trials, commercially available palladium and nickel catalysts were compared along …

Studying Nanoparticle/Cell And Nanoparticle/Biosurface Interaction With Mass Spectrometry, Singyuk Hou

Masters Theses

Nanoparticles (NPs) have been used widely in various fields ranging from biomedical applications to life science due to their highly tunable properties. It is essential to understanding how NPs interact with biological systems of interest, therefore, analytical platforms to efficiently track NPs from cell to animal level are essential. In this thesis, laser desorption ionization mass spectrometry (LDI-MS) and inductively-coupled plasma mass spectrometry (ICP-MS) has been developed and applied to quantify NP/cell and NP/biological surface interactions. These two methods provide fast, label-free and quantitative analysis. New capability of LDI-MS to differentiate cell surface-bound and internalized NPs were established and ICP-MS …

Molecular Interpretation Of A Trigger For Controlling An Amine Isocyanate Polyurethane Reaction, Katherine V. Carrasquillo

Masters Theses

The temperature profile needed to complete the reaction between the sodium-diamine complex and the isocyanate terminated prepolymer has been established. The sodium diamine complex has the advantage of blocking the nearly instantaneous reaction between the diamine and isocyanate from taking place until it is released at elevated temperatures. Because of its low melting temperature (~40 °C) and its low molecular weight (low viscosity), this chain extension reaction is not dependent on the participation of the prepolymer. Instead, the rate of reaction is dependent on the dissolution of the 4,4’-methylenedianiline (MDA) complex into the system. The dissolution of the MDA complex …

Biodegradable Nano-Hybrid Polymer Composite Networks For Regulating Cellular Behavior, Charles Henley Sprague

Masters Theses

Photo-crosslinkable polymeric biomaterials have emerged in the field of biomedical research to promote tissue regeneration. For example, scaffolds that can be crosslinked and hardened in situ have been known to make suitable implant alternatives. Since injectable and photo-crosslinkable biomaterials offer the advantage of being minimally invasive, they have emerged to compete with autografts, a current highly invasive method to repair diseased tissue. A series of novel photo-crosslinkable, injectable, and biodegradable nano-hybrid polymers consisting of poly(ε-caprolactone fumarate) (PCLF) and polyhedral oligomeric silsesquioxane (POSS) has been synthesized in our laboratory via polycondensation. To engineer the material properties of the nano-hybrid networks, varied …

Real-Time Spectroscopic Analysis Of Microalgal Adaptation To Changing Environmental Conditions, Robert Ked Byrd

Masters Theses

Increases in anthropogenic pollution are causing many environmental problems; understanding their impact on the environment has become an important issue. Industrialization and the burning of fossil fuels have caused increased levels of carbon dioxide to enter the atmosphere, which is contributing to global warming and ocean acidification. Agricultural runoff has caused levels of inorganic nitrogen and phosphorus to rise, where they have been noted to cause harmful algal blooms. Marine ecosystems have been particularly affected as both of these forms of pollution accumulate in bodies of water. Microalgae are important organisms in these ecosystems because they sequester these pollutants and …

Synthesis Of New Platinum-Based Anti-Cancer Drugs, Saud O. Albaroodi Yasser

Masters Theses

Cancer is considered the second leading cause of death after heart attack. Different treatments have been applied to kill cancer cells such as chemotherapy, which is the use of chemicals or drugs in order to treat cancer cells. Platinum-based anti cancer drugs are the backbone of chemotherapy, they play a crucial role in treating various malignant tumor. However, the disadvantages of these drugs are very painful on patients, such as nephrotoxicity and ototoxicity. In the last four decades, thousands of platinum-based anticancer drugs have been synthesized for hope in find a new drug with higher efficacy and less side effects.In …

Correlating Morphology To Performance In Conjugated Polymer Nanocomposite Thin Films, Siddharth Pradhan

Masters Theses

The morphology and performance of thin films that consist of conjugated polymers and nanoparticles are investigated in this thesis. In the first system, the morphology of the nanocomposite that consists of low band gap alternating copolymers with a methano-fullerene are determined by neutron scattering and correlated to their photovoltaic performance as polymer solar cells. These results show that the conjugated alternating copolymers have high miscibility relative to other conjugated polymers. The analysis of the scattering data shows that the morphology of the conjugated polymer-fullerene bulk heterojunction can be described as the formation of aggregates on two length scales. Important parameters …

Comparison Of Activation Enthalpies For Aminoglycoside Modification Reactions, Brittany Sterling Soto

Masters Theses

At highly elevated temperatures, many biological reactions can proceed spontaneously from the ground state to the transition state. However, due to the long half-life of these reactions, catalysts are required to catalyze these reactions at modern day temperatures by lowering the activation energy. Wolfenden et al. has previously shown that catalysts enhance the rate of the reaction by reducing the enthalpy of activation. Therefore, the activation energies have been determined for three aminoglycoside modifying enzymes, APH(3’)-IIIa, AAC(3)-IIIb, and AAC(3)-VIa, to determine whether these three enzymes distinguish between the two classes of aminoglycoside antibiotics by reducing the enthalpy of activation during …

Characterizing Groundwater Ch4 And 222rn In Relation To Hydraulic Fracturing And Other Environmental Processes In Letcher County, Ky, St. Thomas Majeau Ledoux

Masters Theses

Hydraulic fracturing of shale deposits has greatly increased the productivity of the natural gas industry by allowing it to exploit previously inaccessible reservoirs. However, previous research has demonstrated that this practice can contaminate shallow aquifers with CH₄ [methane] from deeper formations. This study compares concentrations and isotope compositions of CH₄ sampled from domestic groundwater wells in Letcher County, Kentucky in order to characterize its occurrence and origins in relation to neighboring hydraulically fractured natural gas wells. Additionally, this study tests the reliability of ²²²Rn [radon] as an alternative tracer to CH₄ in identifying processes of gas …

Catalytic Methane Dissociative Chemisorption Over Pt(111): Surface Coverage Effects And Reaction Path Description, Inara Colon-Diaz

Masters Theses

Density functional theory calculations were performed to study the dissociative chemisorption of methane over Pt(111) with the idea of finding the minimum energy path for the reaction and its dependence on surface coverage. Two approaches were used to evaluate this problem; first, we used different sizes of supercells (2x2, 3x3, 4x4) in order to decrease surface coverage in the absence of pre-adsorbed H and CH₃ fragments to calculate the energy barriers of dissociation. The second approach uses a 4x4 unit cell and surface coverage is simulated by adding pre-absorbed H and CH₃ fragments. Results for both approaches show …

A Simpler Route To Building Photochromic Cinnamaldehyde Semicarbazones, Byron R. Ebbert

Masters Theses

Photochromic semicarbazones are an interesting group of compounds that show potential in a broad range of applications, including as a more environmentally friendly replacement for photochromic metal complex compounds. Previous work has shown the feasibility to synthesize photochromic cinnamaldehyde semicarbazones (CSCs) from a benzaldehyde and a protected acetaldehyde Wittig reagent. A new, quicker, and cheaper approach to constructing these CSCs from crotonaldehyde was explored in this research. A three reaction sequence would convert crotonaldehyde to a CSC; first, an allylic bromination of the semicarbazone with N-bromosuccinimide (NBS); second, an Arbuzov reaction to prepare the semicarbazone phosphonate; and finally a condensation …

Synthesis Of Different Sizes & Functions Nanoparticles, Jiaming Geng

Masters Theses

"Nanogels, whose size range from 1 to 100nm, have been interested in many research areas: cosmetics, pharmaceuticals, catalysts, photochemistry, and in optical switches or sensors. In Petroleum Engineering area, nanogels can be used as conformance control agent and emulsion stabilizer. And after grafting functional groups or hybrid, nanogels can be used as tracer for the visual modeling.

Though nanoparticles have been studied for more than 20 years, few of them are about nanogels. In the thesis, stirring rate, surfactant type and concentration were found have a large impact on the synthesis of nanogels. And cationic nanogels have salt and acid …

Cappack Devices For Enhanced Qnmr Measurements In 1H Nmr Spectroscopy, Lingyu Chi

Masters Theses

"Quantitative NMR analyses can be improved by adding well-defined external references for measuring sample properties on absolute scales. Special Capillary-tube Package (CapPack) devices were invented that provide in situ information (e.g., temperature, pH, pressure, integration, chemical shift, lock, etc.) about a sample with spectral imprimaturs. A new microscale glass-sealing technique produced CapPack devices that can survive high temperatures and pressures in harsh environments. Two CapPack devices are discussed: (1) Gradient CapPack-- a device for examining the irradiation bandwidth of solvent-suppression pulse sequences; (2) T₁ CapPack - a device for examining the T₁ robustness of solvent-suppression pulse sequences. A …

In Vitro Study Of Wound-Healing Capabilities Of Bioactive Glass Fibers Under Various Culture Conditions, Sisi Chen

Masters Theses

"Bioactive borate glass has been recognized to have both hard and soft tissue repair and regeneration capabilities through stimulating both osteogenesis and angiogenesis. However, the underlying physiological and cellular mechanism behind this function remains unclear. In this study, in vitro dynamic flow modules were designed to mimic the micro-environment near the vascular depletion and hyperplasia area in wound-healing regions, and were used to investigate the biocompatibility and functionality of borate glass nano-/micro-fibers. Glass-cell interactions were investigated either by dosing fibers to the upstream of or co-cultured with cells, and two types of borate glasses (with or without CuO/ZnO doped were …

Derivatization And Separation Of Natural Estrogens (Estrone, 17Β-Estradiol, And Estriol) Using Gas Chromatography With Flame Ionization Detection (Gc-Fid), Dena L. Guptill

Masters Theses

A major cause of concern for estrogens found in the environment is that even at very low concentrations (10-100 ng/L) they can have a negative effect on aquatic ecosystems by disrupting endocrine systems. Due to the increasing importance of monitoring the levels of estrogens in the environment, a detection method was developed to identify and quantify three natural estrogens (estrone, 17β-estradiol and estriol) using gas chromatography with flame ionization detection (GC-FID). In addition, the efficacy of two derivatizing agents, N,O-bis(trimethylsilyl) acetamide (BSTA) and N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), was evaluated. The GC detector (FID) was most responsive with E3, followed by E1 and …

Novel Bodipy Dyes For Dye-Sensitized Solar Cells, Hafsah Klfout

Masters Theses

Dyes-sensitized solar cells (DSCs) are of importance to efficient conversion of solar energy to electricity. The modern version of a DSC is a titanium dioxide nanoparticles-based electrochemical device, in which solar energy is absorbed by dye molecules and electrons from excited dye molecules are injected into the conduction band of titanium dioxide nanoparticle. The electrons are then transported through a network of interconnected TiO₂ particles to the fluorine- tin -oxide layer to the external circuit. In this process dye molecules are crucial to the device's energy conversion efficiency.

Boron-dipyrromethenes, known as BODIPY dyes, show strong absorption in the visible …

Investigation Of Β-Cyclodextrin's Ability In Differentiating Chiral Guest Molecules And Synthesis Of 1,6-Diphenyl-2,4-Hexadiene-1,6-Dione, Guang Yang

Masters Theses

This research work comprised two projects. The first one mainly focused on the synthesis of 12 alanine derivatives and analysis of their interactions with β-cyclodextrin through ¹H NMR titration. And the other project was an investigation of the conjugation effect of alkynones in its addition reactions with tributyltin hydride.

The synthesis of the alanine derivatives involved methyl esterification of alanine and then the substitution of an NH hydrogen with a benzoyl group. A total of 4 different substitution groups, labeled as the "A" groups, were introduced on the para-position of the benzoyl's phenyl group. Since alanine has one chiral …

Morphological And Surface Chemistry Characteristics Of Silica Nanoparticle Based Cryogels From Specific Processing Parameters, Ben Walusiak

Masters Theses

The goal of this research was to determine the effects of processing conditions on the morphology and surface chemistry of silica nanoparticle based cryogels. All processing conditions resulted in a change in morphology or surface chemistry compared to the starting material, CAB-O-SIL HS5 fumed silica. N₂ adsorption isotherms were used to characterize surface area and pore size distributions of fumed silica and silica cryogels. TGA (thermogravimetric analysis) was performed on all samples in order to characterize the adsorbed water and hydroxyl group content of the silica surface. Solid state ²⁹Si NMR was also used to evaluate surface chemistry …