Chemistry Commons^™

A Spatial Heterodyne Spectrometer For Raman Imaging And Remote Spectroscopy, Ashley Nicole Allen

Theses and Dissertations

Raman and Laser-Induced Breakdown Spectroscopy (LIBS) are optical techniques that provide information about the chemical makeup of a sample without any preparation or physical contact with it. For this reason, Raman and LIBS spectrometers are among the instruments selected for NASA’s Mars 2020 rover mission and are being considered for future missions to the Jovian moons, asteroids and comets. Such future missions will require smaller, more ruggedized Raman and LIBS spectrometers, and the new type of spectrometers discussed here, the spatial heterodyne Raman and LIBS spectrometers are being developed for this purpose. The SHS is a wide-field, Fourier transform, stationary …

Cationic Cobaltocene Derivatives And Polyelectrolyte Membranes For Energy Storage Applications, Tianyu Zhu

Theses and Dissertations

Metal-containing polyelectrolytes (or metallo-polyelectrolytes) represent a new class of polymeric materials with distinct properties compared to traditional organo- polyelectrolytes or neutral metallopolymers. This emerging class of synthetic materials is ubiquitous for a myriad of utilities ranging from traditional electrolyte chemistry to biomedicals to sustainable applications, to name just a few. This dissertation work is focused on the design, synthesis, characterization and application of advanced metallo- cations and metallo-polyelectrolytes for energy storage applications. First, a template method to prepare metallo-polyelectrolytes based on cationic cobaltocene and polyethylene backbone was described. The resulting membranes are mechanically tough, ionically conductive and chemically inert. Second, …

Elucidating The Mechanism Of Bone Morphogenetic Protein (Bmp) -Mediated Sox2 Downregulation In Ovarian Cancer, Zainab Motolani Shonibare

Theses and Dissertations

Sex determining region Y-box 2 (Sox2) is a transcription factor essential for maintaining self-renewal and pluripotency of undifferentiated embryonic stem cells. Sox2 is involved in multiple processes of cancer cells, however, regulation of Sox2 expression and the consequences of that regulation in cancer remains elusive. Previously, we demonstrated that BMP9/GDF2 is significantly reduced in expression in ovarian cancer (OVCA) cells, methylated in patient tumors and, promoted anoikis resistance in both breast and OVCA cell lines. In an attempt to identify genes downstream of BMP9 that may provide anoikis resistance, transcriptomics was performed leading to the identification of Sox2, a developmental …

Investigation Of Electrostatic Interactions Towards Controlling Silylation-Based Kinetic Resolutions And Exploring The Effect Of The Polymer Backbone On Silylation-Based Kinetic Resolutions Employing A Polymer-Supported Triphenylsilyl Chloride, Tian Zhang

Theses and Dissertations

This dissertation focuses on studies of silylation-based kinetic resolution methodology developed by the Wiskur group, which is a powerful method for the separation of a single enantiomer from a mixture of racemic secondary alcohols. Chapter 1 introduces the background of our silylation-based kinetic resolution..

Chapter 2 involves mechanistic studies of electrostatic interactions in controlling enantioselectivities of our silylation-based kinetic resolution. Electrostatic interactions between a silylated isothiourea intermediate and an ester π system is determined via linear free energy relationship study. To be specific, how variations in sterics and electronics affect the selectivity of a silylation-based kinetic resolution.

Chapter 3 is …

The Development Of Multi-Functional System That Combine Patterned Hydrogels, Plasmin-Degradable Nanoparticles And Stem Cells For Applications In Tissue Engineering And Growth Factors Delivery, Safaa I. Kader

Theses and Dissertations

This thesis spots the light on the development of a novel multi-functionalized system for application in tissue engineering and on-demand morphogens delivery. Three types of materials used in this study are synthetic polymer, biopolymer, and nanomaterials. Polyethylene glycol (PEG), a synthetic polymer was chosen in this study because of its high biocompatibility, non-immunogenicity, inert nature, ease of modification, and reduces protein denaturation to provide a wide range of physical and mechanical properties. Here, PEG is used one time as a hydrogel, linear polyethylene glycol-co-lactide (LPELA), and another time as peptide-PEG based nanoparticles (PxSPCP). Gelatin, a natural polymer has been widely …

Novel Self-Assembly Of Fullerene-Based Dyads, Ashley D. Anderson

Theses and Dissertations

Eventual depletion and environmental toxicity of natural non-renewable energy resources are two issues pushing research toward alternative energy resources. Nature’s process of renewable, unlimited, clean energy production is photosynthesis and porphyrins are a critical component due to their ability to undergo photoinduced electron transfer. This property also makes porphyrins excellent candidates for applications such as solar cells, water splitting, and optical sensing. Researchers have previously tethered porphyrins to fullerene (C60), an excellent electron acceptor, to mimic the reaction centers in photosynthesis. Photoinduced electron transfer in these donor-acceptor dyads has been investigated with particular focus on factors such as the donor, …

Removal Of As (Iii) And As (V) From Potable Water Using Zno Nanoparticles, Grecia Torreblanca Baez

Theses and Dissertations

Heavy metal and toxic element contamination of the environment has been increasing with increasing industrialization. Arsenic has become an element of particular concern because of its toxicity, which is oxidation state dependent. As(III) is observed to be much more toxic than As(V), as well the removal is more difficult than As(V) in traditional water treatment technology. In the present study, As (III) and As(V) removal was investigated using a zinc oxide nanomaterial that was synthesized using a titration/precipitation technique, and characterized using powder x-ray diffraction. In the present study, the kinetics of adsorption, the adsorption isotherms as well as the …

The Investigation Of Secondary Particle Formation Initiated By Non-Prototypical Sources And The Role Of Amines In The Atmosphere, Emily Burrell

Theses and Dissertations

This dissertation is a collection of works that investigate non-prototypical sources leading to new particle formation in the atmosphere. Particles play a major role in atmospheric chemistry. For example, particles are a component of smog and are commonly found in high concentrations under conditions of atmospheric inversions. In order to reconcile the difference between measured and modeled particle concentrations new mechanisms from non-prototypical sources for particle formation need to be determined. Formation of particles has frequently been modeled using classical nucleation theory (CNT). The first step in CNT is the nucleation step where molecular clusters form. In a second step, …

Preparation, Functionalization, And/Or Characterization By X-Ray Photoelectron Spectroscopy Of Carbon Surfaces For Biosensors And Other Materials, Varun Jain

Theses and Dissertations

My dissertation is primarily divided into two parts. The first deals with the preparation, functionalization, and characterization of carbon surfaces prepared by direct current magnetron sputtering (DCMS) and high power impulse magnetron sputtering (HiPIMS) as substrates for bioarrays. Part two discusses applications of XPS peak fitting in surface chemical analysis. Chapter 1, the introduction, includes (i) a discussion of the construction of bioarrays and the preparation of sputtered surfaces, e.g., by DCMS and HiPIMS, and also functionalization (bioconjugate) chemistry with special emphasis on the importance of covalent functionalization of surfaces, and (ii) a discussion of the surface characterization techniques and …

Organic-Inorganic Hybrid Materials For Piezoelectric/Triboelectric Nanogenerator, Aminur Rashid Chowdhury

Theses and Dissertations

Nanogenerator has been a major focus among researchers of recent time due to its versatile use in everyday life. Though the discovery of the piezoelectricity and the triboelectricity dates back to 19th century, the use of these phenomena has not been in practical use till 2006. In this study we demonstrate the practical application of piezoelectric and triboelectric nanogenerator comprised of different copolymer and piezoelectric ceramic. The largely known piezoelectric polymer Polyvinylidene fluoride (PVDF) has also been utilized. The enhancement of piezoelectric properties of PVDF has been achieved by utilizing surface activation of accommodating ceramic. The Li doped ZnO has …

Computational Studies Of High-Oxidation State Main-Group Metal Hydrocarbon C-H Functionalization, Clinton R. King

Theses and Dissertations

High-oxidation state main-group metal complexes are potential alternatives to transition metals for electrophilic C-H functionalization reactions. However, there is little known about how selection of the p-block, main-group metal and ligand impact C-H activation and functionalization thermodynamics and reactivity. Chapter 2 reports density functional theory (DFT) calculations used to determine qualitative and quantitative features of C-H activation and metal-methyl functionalization energy landscapes for reaction between high-oxidation state d10s0 InIII, TlIII, SnIV, and PbIV carboxylate complexes with methane. While the main-group metal influences the C-H activation barrier height in a periodic manner, the carboxylate ligand has a much larger quantitative impact …

Modified Ambient Mass Spectrometric Methods For Field Screening And Confirmation Of Forensic Evidence, William Lee Fatigante

Theses and Dissertations

The utility of field-portable analytical instrumentation has the potential to revolutionize many fields of science, particularly for forensic science and law enforcement. While colorimetric testing can be employed for drug evidence screening, the influx of novel psychoactive substances has significantly decreased the effectiveness of this investigation strategy. One approach to meeting the needs of today’s practitioner is coupling flexible, ambient ionization techniques with portable mass spectrometric (MS) instrumentation. Ambient ionization techniques have a rich history of being amendable to the sample at hand. Since their inception in 2005, numerous techniques saturate the field. The main drive for this development is …

Potential For On-Site, Prosecutorial Evidence From Drug Residues Collected On Plasmonic Paper: A Pilot Study For Sers-Psi-Ms, Daniel S. Burr

Theses and Dissertations

Given the potential impact of improvements to on-site drug testing, as well as recent, successful displays of paper spray ionization mass spectrometry (PSI-MS) in this regard, this thesis pilots the implementation of Raman spectroscopy as a compliment to MS for field-based confirmatory drug testing. Surface enhanced Raman scattering (SERS) is utilized for applications to trace detection. Two-tiered analysis of individual drug samples is enabled using triangularly-cut plasmonic papers, from which both SERS and PS-MS analysis may be performed. Several drug compounds, representative of traditional and emerging drug types, are examined by these techniques, both separately and as a fully integrated, …

Fluidic Control System Development For Fluorescence Imaging Photometer, Ergün Kara

Theses and Dissertations

Phytoplankton are the primary autotrophic organisms in the marine food web and they produce nearly half of the global oxygen as a photosynthetic by-product [1]. Through photosynthesis, phytoplankton annually fix between 30 and 50 billion metric tons of atmospheric carbon into the marine systems, which approximately accounts for 40% of total carbon fixation [2]. Furthermore, the phytoplankton population trends are important indicators of the environmental perturbations [3]. Therefore, detection and characterization of the phytoplankton species is an important goal of the science. Several spectrometric, cytometric and microscopic techniques are already employed for characterization and quantification of the phytoplankton communities [4-6]. …

Metastable-State Photoacids And Polymers With High Photoacidity, Thaaer Khalil

Theses and Dissertations

In recent years, metastable-state photoacids (mPAH) have been utilized to control various chemical processes using visible light and have found many applications in materials, energy, and biomedical areas. An introduction of metastable state photoacid is given in Chapter 1. In chapter 2, to clearly understand the relationship between the structures and the physicochemical properties of mPAHs, a series of mPAHs were designed and synthesized. The reversibility, stability, reverse reaction rate, and photoreaction of the mPAHs were studied in detail using UV/VIS spectroscopy. The results demonstrated that the electron-withdrawing groups on the electron-accepting moiety enhance the overall photoreaction and stability of …

Disinfection By-Products: Method Optimization For Quantification, Unknown Analysis, And Calculated Toxicity, Amy A. Cuthbertson

Theses and Dissertations

Disinfected drinking water contains hundreds of disinfection by-products (DBPs) that are formed by the reaction of disinfectants with natural and anthropogenic organic matter, bromide, and iodide. Understanding what these DBPs are is important because millions of people worldwide consume drinking water every day, and human epidemiologic studies have reported cancer, miscarriage, and birth defects from consuming such waters. While more than 700 DBPs are reported in the literature, very few studies quantify complete classes of chlorinated, brominated, and iodinated DBPs. The following document contains five chapters in the format designated for specific scientific journals on this subject. Chapter 1 describes …

Non-Destructive Determination Of Magnetic Audio Tape Degradation For Various Tape Chemistries Using Spectroscopy And Chemometrics, Alyssa Marie Abraham

Theses and Dissertations

This dissertation focuses on creating a non-destructive method for the identification of degraded magnetic audio tapes using attenuated total reflectance Fourier transform infrared spectroscopy (ATR FT-IR) and chemometrics. The primary recording medium during the second half of the twentieth century was magnetic tapes. These tapes hold some of the world’s modern cultural history. Unfortunately, the majority of these tapes were made with a polyester urethane (PEU) binder, which has shown to degrade through hydrolysis of the ester component, called sticky shed syndrome (SSS). As the name implies, degraded tapes will stick and shed onto player guides and heads during playback. …

Semiconductor Nanowire Doping: Controlling Magnetic And Electronic Properties Of Colloidal Nanowares, Preecha Kittikhunnatham

Theses and Dissertations

Electronic devices have been utilized in a wide range of applications, such as computing, data storage, sensors, lightings, energy production, and energy storage; they are building blocks of computer processors, solid state data storage devices, image sensors in digital cameras, LEDs, and solar cells, etc. These electronic devices operate based on properties of semiconductors, which are their essential components. Not only being fundamental components of electronic devices, semiconductors can be crucial materials for other applications, such as catalysts, battery electrodes, etc. One of the primary current quest on semiconductor research is to develop semiconducting materials that are more compact and …

Metastable-State Photoacid: A Comprehensive Theoretical Study Of The Photoreaction, Reverse Reaction, Thermal Isomerization, And Td-Dft Absorption In Solvent, Arwa Wasel Hamed Alharbi

Theses and Dissertations

The main objective of the research is to investigate the fundamentals of novel metastable-state photoacids. These photoacids can reversibly produce a large concentration of protons while undergoing photo-irradiation. This change in proton concentration can induce and catalyze chemical reactions, biological functions, and material properties that do not occur in the dark. (IMAGE) Scheme 1. Energy diagram of the photoreaction. (The red route is the forward photoreaction; the blue route is the reverse reaction; and the process that involves the proton dissociation of the photoacid in the dark is the green route; "t-" means trans- and "c-" means cis-). Scheme 1 …

Analysis Of N-Alkanes And N-Alkenes In Chukchi Sea Sediments, Salomey Asantewaa Sasu

Theses and Dissertations

This study determined the concentrations, distribution and sources of n-alkanes in core sediments from four locations: Stations H24, H30, H32 and BarC5 in the Chukchi Sea, which is in the Arctic Ocean. n-Alkanes are valuable tracers of aquatic, terrigenous and petroleum inputs and may give evidence to the extent of climate change. The study of climate change in the Arctic is important since the Arctic is warming faster than any other part of Earth. The increase in temperature is causing enhanced evaporation leading to a higher precipitation rate and hence enhanced erosion. The n-alkanes C12-C35 were analysed and characterized using …

Model Pt-Re And Pt-Sn Surfaces For Heterogeneous Catalysis, Thathsara Deshani Maddumapatabandi

Theses and Dissertations

The dissertation is focused on understanding the growth, morphology and activity of model heterogeneous catalytic surfaces. Vapor deposited metal clusters on single crystal surfaces are well-defined systems that can be used to understand the growth, composition and activity relationships in commercial catalysts. A fundamental understanding of surface reactions is required in order to provide insight into the development of new catalytic materials. The model catalysts approach allows for systematic investigations due to excellent control over growth, composition and characterization under a carefully controlled ultrahigh vacuum (UHV) environment.

The nucleation, growth and chemical activity of monometallic and bimetallic Pt-Re clusters on …

Mechanistic Studies Of Atypical Reactions And Uncommon Substrates Native To Bacterial Cytochrome P450 Enzymes OletJe And Nikq, Courtney Elizabeth Wise

Theses and Dissertations

Cytochrome P450 (CYP) enzymes typically perform hydroxylation chemistry on small molecule substrates using atmospheric oxygen and electrons from redox partner proteins. This reactivity is dependent on a thiolate-ligated heme cofactor that also allows for spectroscopic detection of ligation, oxidation, and environmental changes to the iron metal. The onset of the genomics era has resulted in the discovery of CYPs that deviate from this paradigm in terms of reaction performed, cosubstrate requirements, and substrate-scope. This work focuses on two of these unusual P450s – OleT and NikQ. OleT performs an unconventional H2O2-dependent decarboxylation reaction on a standard small molecule fatty acid …

Probing The Relationship Of Cyanobacterial Toxins And Reactive Oxygen Species Within The Natural World, Meagan Lachelle Smith

Theses and Dissertations

The occurrence of harmful algal blooms (HABs) and their impacts on human health and the economy are only expected to worsen in the coming years, mainly due to climate change related factors. In Lake Wateree, SC, a HAB of the species Lyngbya wollei, has been persistent for more than 10 years and is estimated to occupy 60 - 90 km of shoreline. This natural laboratory provided and continues to provide a unique window into the chemistry and microbial ecology of HABs. Work in this dissertation was directed at answering a critical question: are biomass-to-toxin ratios constant in HABs? Initial …

Bimetallic Systems For Heterogeneous Catalysis And Tuning Electronic Properties Of Functional Materials, Amy J. Brandt

Theses and Dissertations

Throughout the past few decades, advancements have been made in altering monometallic materials through addition of a second metal to create a bimetallic material that displays enhanced properties over its monometallic components and optimized attributes toward the intended application. However, a lack of fundamental understanding of the interactions between the two metals and between the metals and their environment can hinder the process of designing enhanced functional materials with desirable properties. In this work, careful analysis of model catalysts and metal-organic frameworks (MOFs) is performed in ultrahigh vacuum, and evaluation of the catalytic activity of the catalysts and electronic properties …

Biochemical Investigations Of Proteins Associated With Iron Homeostasis In Escherichia Coli, Matthew Ryan Blahut

Theses and Dissertations

The regulation of transition metals within living organisms is essential to the persistence of life. Of particular interest to our lab is iron due to the prevalence of this metal within the cell in addition to the numerous functions it performs. Fe-S cofactors are a significant prosthetic group consisting of iron that are necessary for the function of various metalloproteins. Generation of Fe-S clusters depends on several biosynthesis pathways varying between organisms with Isc and Suf both utilized in E. coli. While Isc controls Fe- S manufacturing under normal conditions, Suf assumes control when the cell is exposed to …

Investigation Of Energy-Related Wastewater Impacts On Disinfection By-Product Formation In Drinking Water, Hannah K. Liberatore

Theses and Dissertations

Elevated bromide and iodide in drinking water sources contribute to the formation of toxic brominated and iodinated disinfection by-products (DBPs) during drinking water treatment. Energy extraction and utilization processes, including hydraulic fracturing (HF) and coal-fired power plants (CFPPs), produce wastewaters with bromide/iodide levels on the order of tens to thousands of mg/L. These wastes have the potential to impact drinking water sources through both intentional (e.g., direct discharge) and accidental (e.g., basin overflow, spill) release pathways. This research focuses on a combination of quantitative and non-targeted approaches to assess DBP formation impacts from HF and CFPP wastewaters, with complementary toxicity …

Investigating Color Additive Molecules For Pharmaceutical And Cosmetic Applications: A Comparison Of Theoretical And Experimental Uv-Visible Absorbance Spectra In Tunable Solvents, Jacqueline Casey Mohen

Theses and Dissertations

Color additive molecules have widespread applications ranging from ingestible foods and pharmaceutics to non-ingestible cosmetics and other naturally or synthetically developed consumer products available worldwide. Certification for approved use of color additives varies globally; therefore, a feasible method to analyze existing color additives or to design novel color additive molecules with enhanced or otherwise desired physicochemical properties (such as hue) is in high demand for universal adoption. The studies herein provide sufficient proof that density functional theory and time-dependent density functional theory serve as effective predictive modeling techniques for generating theoretical maximum absorbance spectral peak responsivity for a single color …

Computational Design And Analysis Of Molecular Ethylene Oligomerization Catalysts, Doo Hyun Kwon

Theses and Dissertations

Linear alpha olefins (LAOs) are key petrochemical precursors for the synthesis of larger polymers, detergents, plasticizers, and lubricants. Most catalytic ethylene oligomerization processes generate a wide distribution of LAO carbon chain lengths. A major ongoing industrial challenge is to develop homogeneous catalysts that result in selective and tunable ethylene oligomerization to 1-hexene and 1-octene alkenes. Quantum mechanical calculations coupled with rapidly advancing technology have enabled the ability to calculate small molecule systems with high accuracy. Employing computational models to advance from empirical to quantitative prediction of product selectivities has become an active area of exploration. In this work, we demonstrate …

A Robust And Automated Deconvolution Algorithm Of Peaks In Spectroscopic Data, William Johan Burke Iv

Theses and Dissertations

The huge amount of spectroscopic data in use in metabolomic experiments requires an algorithm that can process the data in an autonomous fashion while providing quality of analysis comparable to manual methods. Scientists need an algorithm that effectively deconvolutes spectroscopic peaks automatically and is resilient to the presence of noise in the data. The algorithm must also provide a simple measure of quality of the deconvolution. The deconvolution algorithm presented in this thesis consists of preprocessing steps, noise removal, peak detection, and function fitting. Both a Fourier Transform and Continuous Wavelet Transform (CWT) method of noise removal were investigated. The …

Studies On Regulation Of Dihydrotestosterone Binding To And Releasing From The Androgen Receptor, Tahyra M. Resto Santos

Theses and Dissertations

The androgen receptor (AR) is a nuclear receptor that responds to testosterone and 5α-dihydrotestosterone (DHT) by modulating gene expression in a variety of cells, including prostate and muscle tissues. Studies of small molecule interaction with AR have shown diphenyl compounds inhibiting through a binding site labeled Binding Function 3 (BF3). The goal of this research is to analyze the interaction of the BF3 site with DDT and related compounds. Amino acids that are exposed on the surface of the BF3 that might interact with different compounds were mutated. Mutant proteins were tested experimentally for their impact on the inhibition the …