Chemistry Commons^™

Laser-Induced Fluorescence Imaging Of Calcium And Barium Ion Beams In The Second Vacuum Stage Of A Commercial Inductively Coupled Plasma Mass Spectrometer, Alisa Jane Edmund

Theses and Dissertations

Inductively coupled plasma-mass spectrometers (ICP-MS) have become the workhorses of many analytical labs over the past few decades. Despite the instruments' high sensitivities and low detection limits there is still a demand for improvements in several aspects of their performance. One area of improvement is in the understanding of "space charge effects" Space charge effects are classified as problems associated with the ion beam. Problems are created when the mutual repulsions of the ions make consistent focusing of the ion beam difficult. This is particularly problematic with samples containing a low concentration analyte contained within a high salt solution matrix, …

Examination Of Quasienantiomers Of Oxadiazinanones Which Fail To Fractionally Crystallize, Patricia Ann Higgins

Theses and Dissertations

This thesis reports the crystallization of two new quasiracemic crystals, the synthesis of a new oxadiazinanone, and the identification of crystals of two new compounds. In previous research the quasiracemates, (5,R,6,S)-4-cyclohexyl-5-methyl-6-phenyl-2H-1,3,4-oxadiazinan-2-one and (5S,6R)-4-isopropyl-5-methyl-6-phenyl-2H-1,3,4-oxadiazinan-2-one, were mixed in solution and crystallized. Instead of fractionally crystallizing, as would be expected, the compounds formed quasiracemic co-crystals. This suggested that other mixtures of oxadiazinanones would be possible candidates for studying compounds which fail to fractionally crystallize.

The first step in the process involves the synthesis of oxadiazinanones, using literature methods. A 4-step process …

Discovery Of Novel Serum Biomarkers For Diagnosing And Staging Alzheimer's Disease, Dipti Jigar Shah

Theses and Dissertations

Discovery of Novel Serum Biomarkers for Diagnosing and Staging Alzheimer’s DiseaseDipti Jigar ShahDepartment of Chemistry and Biochemistry, BYUDoctor of PhilosophyAlzheimer’s disease (AD) is an untreatable neurologic disease affecting more than 5 million Americans, most over 60 years of age. Protein plaques and neurofibrillary tangles typify AD brain pathology and are thought to cause the progressive dementia and brain shrinkage observed in AD. Currently there are no methods to diagnose the disease at a time before damage becomes irreversible.Biochemical tests for AD using cerebrospinal fluid analysis or neuroimaging are not yet sufficiently sensitive and specific, and they are invasive. This points …

Use Of Carbon Dioxide (Co2) And Its Congeners For The Synthesis Of Small Value Added Chemicals Utilizing Chlorostannoxane Catalysts, Sharon Pulla

Theses and Dissertations

Carbon dioxide (CO2) is an abundant, environmentally benign and renewable source of carbon. Use of CO2 may potentially end the use of other toxic C1 synthons, such as phosgene, carbon monoxide, and isocyanate. However, the extreme inertness of CO2 presents great difficulty for its use in organic synthesis. In Chapter 3, the synthesis of cyclic carbonates from corresponding epoxides under low pressures of CO2 (300 psi), relatively mild temperature (130 oC) using chlorostannoxane catalysts is discussed. Activities of the catalysts have been optimized in the pressure range of 100-700 psi, temperature range of 100-130 oC, with reference to propylene oxide. …

Ab-Initio Study Of H2 Adsorption Upon The 001, 110, And 100 Surface Of Magnesium, Thomas F. Armstrong

Theses and Dissertations

Until recently, the only pathway for H2 adsorption onto conventional magnesium thin films was the [001] surface. With the discovery of Mg nanoblade/nanotree fabrication, there are now multiple surfaces for adsorption. A keen understanding of each surface's hydrogen adsorption kinetics is a key part of deciding if these surfaces present a more attractive hydrogen storage material than conventional thin films. This study focused on the use of ab-initio methods to compare the adsorption of H2 molecules onto the [001], [100], and [110] surfaces as well as an analysis of hybrid functionals and their advantages over traditional functionals for minimum energy …

Organic-Inorganic Hybrid Nanostructures For Solar Cell Applications, Samir Mahdi Abdulalmohsin

Theses and Dissertations

The enticing electro-optical properties of nanostructured materials such as carbon nanotubes, graphene, CdS nanocrystals and ZnO nanowrie bring new vigor into the innovation of photovoltaics. The main purpose of this dissertation is to develop novel nano-structured materials for low cost solar cell applications. Fabrication, characterization, and solar cell application of organic-inorganic hybrid structures are the main focus of this research. Polyaniline (PANI)/multi-walled carbon nanotube (MWNT) composite films were synthesized by an electrochemical polymerization of aniline with airbrushed MWNTs on ITO substrates. It was found that the incorporation of MWNTs in PANI effectively increase the film conductivity with a percolation threshold …

Microwave Assisted Synthesis And Characterization Of Selected Heteroatom Doped Carbons From Tannin For Alkaline Fuel Cell Applications & Ammonia Gas Sensors From Tanninsulfonic Acid Doped Polyaniline - Tio2/Al2o3 Composites, Venu Gopal Bairi

Theses and Dissertations

An alternative for depleting fossil fuel resources would be the development of fuel cells, batteries and solar cells. The current project aims at development of the cathode electrode material for alkaline fuel cells which is utilized for the reduction of oxygen to water. A simple, highly efficient, and rapid microwave method for the synthesis of doped carbons from different precursor sources like tannin, aminated tannin and tannin-melamine-hexamine has been developed. Different dopants include phosphorus, nitrogen, oxygen, sulfur and silicon. The method uses no inert or reducing gas during the transformation. Yields resulting from this particular technique are as high as …

Characterization Of Suf Pathway For Fe-S Cluster Assembly In Escherichia Coli, Yuyuan Dai

Theses and Dissertations

Fe-S clusters are critical metallocofactors required for cell function. Because of the toxicity of ferrous iron and sulfide to the cell, in vivo Fe-S cluster assembly is carried out by multiprotein biosynthetic pathways. Escherichia coli contains a stress-responsive Fe-S cluster assembly system, the SufABCDSE pathway, working under iron starvation and oxidative stress conditions. The cysteine desulfurase SufS and its accessory protein SufE work together to mobilize persulfide from L-cysteine. We collaborated with Dr. Laura S. Busenlehner to use hydrogen/deuterium exchange mass spectrometry (HDX-MS) to characterize SufS-SufE interactions and protein dynamics. HDX-MS analysis shows that SufE binds near the SufS active …

Hydroflux Synthesis: A New And Effective Technique For Exploratory Crystal Growth, Michael William Chance

Theses and Dissertations

Exploratory crystal growth is the best way to discover new phases with potentially improved properties or new crystal structures that could lead to new properties. As time goes on and researchers explore the synthetic techniques in the literature, diminishing returns will be met. Innovation in the synthetic tools used for synthesis is necessary to keep the field of materials chemistry advancing at its current pace and to allow us to reach more shallow minima of phase space. By combining wet hydroxide flux synthesis and hydrothermal synthesis, a hybrid technique for crystal growth has been created.

Using hydroxide hydrofluxes, a number …

Investigation Of The 4-Amino-Α,Α-Dihydroxy-3,5-Dichloroacetophenone Impurity In The Synthesis Of Clenbuterol Hydrochloride, Kerry Moore

Theses and Dissertations

Clenbuterol Hydrochloride is a bronchodilator marketed as Spirospent® for Human Pharmaceuticals and as Ventipulmin® for Veterinary Pharmaceuticals by Boehringer Ingelheim.1 This research investigates formation of the 4-amino-α,α-dihydroxy-3,5-dichloroacetophenone impurity (Dihydroxy Impurity) in the synthesis of Clenbuterol Hydrochloride. The Dihydroxy Impurity has increased three-fold since the process was transferred to Boehringer Ingelheim Chemicals, Inc. in 1999.1 The Dihydroxy Impurity is proposed to be produced during an amination/reduction step from a reaction of water with the starting material.2 Additionally, the Dihydroxy Impurity can be formed by the reaction of water with an impurity, 4-amino-α,α-didibromo-3,5-dichloroacetophenone (Dibromo Impurity), that is generated in the previous step.2 …

Determination Of The Factors That Affect The Gas-Phase Reactivity Of Metal-Centered Cyclopropanation Catalysts And Examination Of The Properties Of Their Reaction Products, Jamal Aldajaei

Theses and Dissertations

Gas phase studies of organometallic systems have provided deep insight into reaction mechanisms and reaction intermediates. In this thesis, several metal/ligand systems were examined in an effort to form metal carbenes in the gas phase. With cobalt and iron porphyrins, the carbene undergoes metal-ligand insertion. With copper bis-oxazolines, metal carbenes tend to undergo metal-ligand insertion and a Wolff rearrangement. To avoid insertions, we turned to a rigid ligand, 1, 10-phenanthroline. Under ESI conditions, a copper (I) complex with phenanthroline can be formed. When treated with diazoacetate esters, the dominant product results from addition with loss of nitrogen followed by loss …

Synthesis And Characterization Of Cobalt Carbide Based Nanomaterials, Zachary Huba

Theses and Dissertations

Permanent magnets are used heavily for multiple applications in industry and current electronic technologies. However, the current permanent landscape is muddled by high cost of materials and insufficient magnetic or thermal properties. The primary focus of this dissertation work is the synthesis and optimization of a new permanent magnetic material, in the form of cobalt carbide nanomaterials. The optimization revolved around controlling the crystal phase and particle shape of synthesized cobalt carbide particles; these parameters have significant impact on the observed magnetic properties of magnetic nanoparticles. Co₃C was identified to be the preferred crystal phase, leading to better …

The Roles Of Phosducin-Like Protein 1 And Programmed Cell Death Protein 5 As Molecular Co-Chaperones Of The Cytosolic Chaperonin Complex, Christopher M. Tracy

Theses and Dissertations

A fundamental question in biology is how proteins, which are synthesized by the ribosome as a linear sequence of amino acids, fold into their native functional state. Many proteins require the assistance of molecular chaperones to maneuver through the folding process to protect them from aggregation and to help them reach their native state in the very concentrated protein environment of the cell. This study focuses on the roles of Phosducin-like Protein 1 (PhLP1) and Programmed Cell Death Protein 5 (PDCD5) as molecular co-chaperones of the Cytosolic Chaperonin Complex (CCT).Signaling in retinal photoreceptors is mediated by canonical G protein pathways. …

Ultraviolet Light Emitting Diode Use In Advanced Oxidation Processes, Kelsey L. Duckworth

Theses and Dissertations

Cleanup from a hazardous chemical release can result in large volumes of water containing hazardous materials, such as organophosphates. Unfortunately, this water cannot be treated in a municipal wastewater treatment plant without adversely affecting the performance of the plant. A known method for pretreating this water to prepare it for processing in a traditional treatment plant includes the addition of hydrogen peroxide, followed by ultraviolet (UV) light exposure to form reactive hydroxyl radicals which oxidize the chemical. Light emitting diodes (LEDs) are explored as a UV source as they are durable; compact; can be powered by low voltage, direct current …

Desorption Electrospray Ionization Mass Spectrometry Imaging: Instrumentation, Optimization And Capabilities, Manan Dhunna

Theses and Dissertations

Desorption Electrospray Ionization Mass spectrometry Imaging (DESI-MSI) is an area of great interest and a promising tool in the field of chemical imaging. It is a powerful, label-free technique, which can determine, map and visualize different molecular compounds on a sample surface. The amount of information acquired in a single DESI-MSI experiment is enormous compared to other techniques, as it can simultaneously detect different compounds with their spatial distribution on the surface. The experiment can be used to produce two-dimensional and three-dimensional images. Chapter 2 focuses on the design and optimization of the setup for performing DESI-MS imaging on various …

Facile Synthesis And Characterization Of A Thermally Stable Silica-Doped Alumina With Tunable Surface Area, Porosity, And Acidity, Maryam Khosravi Mardkhe

Theses and Dissertations

Mesoporous γ-Al2O3 is one of the most widely used catalyst supports for commercial catalytic applications. The performance of a catalyst strongly depends on the combination of textural, chemical and physical properties of the support. Pore size is essential since each catalytic system requires a unique pore size for optimal catalyst loading, diffusion and selectivity. In addition, high surface area and large pore volume usually result in higher catalyst loading, which increases the number of catalytic reaction sites and decreases reaction time. Therefore, determination of surface area and porosity of porous supports is critical for the successful design and optimization of …

Nascent Peptides That Induce Translational Arrest, Christopher J. Woolstenhulme

Theses and Dissertations

Although the ribosome is a very general catalyst, it cannot synthesize all protein sequences equally well. Certain proteins are capable of stalling the ribosome during their own synthesis. Stalling events are used by both prokaryotic and eukaryotic cells to regulate gene expression. Characterization of natural stalling peptides shows that only a few strategically placed amino acids are needed to inactivate the ribosome. These motifs share little sequence similarity suggesting that there are more stalling motifs yet to be discovered. Here we use two genetic selections in E. coli to discover novel stalling peptides and detail their subsequent characterization. Kinetic studies …

On Chip Preconcentration And Labeling Of Protein Biomarkers Using Monolithic Columns, Device Fabrication, Optimization, And Automation, Rui Yang

Theses and Dissertations

Detection of disease specific biomarkers is of great importance in diagnosis and treatment of diseases. Modern bioanalytical techniques, such as liquid chromatography with mass spectrometry (LC-MS), have the ability to identify biomarkers, but their cost and scalability are two main drawbacks. Enzyme-linked immunosorbent assay (ELISA) is another potential tool, but it works best for proteins, rather than peptide biomarkers. Recently, microfluidics has emerged as a promising technique due to its small fluid volume consumption, rapidness, low fabrication cost, portability and versatility. Therefore, it shows prominent potential in the analysis of disease specific biomarkers. In this thesis, microfluidic systems that integrate …

Polymeric Monolithic Stationary Phases For Capillary Reversed-Phase Liquid Chromatography Of Small Molecules, Kun Liu

Theses and Dissertations

Highly cross-linked monoliths prepared from single cross-linking monomers were found to increase surface area and stability. Therefore, seven cross-linking monomers, i.e., 1,3-butanediol dimethacrylate (1,3-BDDMA), 1,4-butanediol dimethacrylate (1,4-BDDMA), neopentyl glycol dimethacrylate (NPGDMA), 1,5-pentanediol dimethacrylate (1,5-PDDMA), 1,6-hexanediol dimethacrylate (1,6-HDDMA), 1,10-decanediol dimethacrylate (1,10-DDDMA), and 1,12-dodecanediol dimethacrylate (1,12-DoDDMA), were used to synthesize highly cross-linked monolithic columns in 75-µm i.d. capillaries by one-step UV-initiated polymerization using dodecanol and methanol as porogens for reversed-phase liquid chromatography (RPLC) of small molecules. Selection of porogen type and concentration was investigated in detail. Isocratic elution of alkylbenzenes at a flow rate of 300 nL/min was conducted for all of …

Collisional Dynamic Elements Of The Pyrazine - N2o System:Middle And Low J States, La Moyne Tyler Mix

Theses and Dissertations

Unimolecular reactions based on the Lindemann - Hinchelwood mechanism are important to understanding combustion and atmospheric processes. The main feature of this mechanism is the energy transfer probability distribution function, P(E',E). We have chosen to study P(E',E) through gas phase collisional dynamics probed with IR transient absorption spectroscopy. Post-collision absorption line widths for the pyrazine-N2O system are used to calculate lab frame translational temperatures. The translational temperatures reveal that collisions with large rotational energy transfer also transfer large amounts of translational energy. For J states >47 the relationship is linear indicating a constant impact parameter. Line widths for J=47 through …

Advancements In The Design, Synthesis, And Application Of Polybenzimidazoles, Alexander Lanier Gulledge

Theses and Dissertations

The overall goal of the work presented within this thesis is to investigate, understand, and develop structure-property relationships in regards to polymer structure, membrane stability, and device performance. Previous work has shown that material properties such as acid loading, proton conductivity, mechanical integrity, and device performance can be attributed to polymer structure, chemical functionality, and polymer architecture (homo, random, co-polymer etc.). Developing and understanding these relationships is critical to the advancement of fuel cell technology. Within this thesis, several of these relationships are investigated and reported.

Novel polymers and copolymer systems have been developed in this research and have significantly …

Quantitative Mass Spectrometric Investigations Of Protein Biomarkers: Serum Thymidine Kinase 1 And Human Osteopontin, Morse Faria

Theses and Dissertations

Mass spectrometry is being increasingly used in biomarker research mainly due to its ability to achieve high selectivity coupled with high sensitivity. This dissertation focuses on quantitative mass spectrometric investigations of two protein biomarkers i.e. serum thymidine kinase 1 (TK1) and human osteopontin (OPN).

First part of this research was focused on developing a liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method for measuring the activity of TK1 in serum by monitoring the conversion of a TK1 specific exogenous substrate, 3’-deoxy-3’-fluorothymidine (FLT), to its mono-phosphorylated form 3’-deoxy-3’-fluorothymidine monophosphate (FLT-MP). A method to quantify FLT-MP on LC-MS/MS was developed and …

Exploring The Asymmetric Environment Of Various Chiral Catalysts Using A Modified Ion-Trap Mass Spectrometer: Towards The Development Of A Rapid Chiral Catalyst Screening Method, Cary M. Davis

Theses and Dissertations

Since the tragedy of the drug Thalidomide® in the late 1950 to early 1960’s, chirality has been recognized as an important aspect that must be controlled in the drug development process in the pharmaceutical industry. Since then, there has been a considerable movement towards single enantiomer drugs. This demand has presented many challenges for the synthetic organic chemist. Chiral catalysts offer one solution to this problem, as they afford the unique ability to preferentially synthesize one enantiomer. Unfortunately, the design of new chiral catalysts is often empirical, with luck and trial and error necessary due to factors that govern enantioselectivity. …

Catalytic Activity Of Heteropoly Tungstophosphoric Acid Supported On Partially Reduced Graphene Oxide Prepared By Laser And Microwave Irradiation, Mark Paul Jimena Dailo

Theses and Dissertations

The solid acid catalyst of the Keggin-type 12-tungstophosphoric acid (H₃PW₁₂O₄₀, HPW) is supported on partially reduced graphene oxide (PRGO) nanosheets for acid-catalyzed reactions. HPW is a new class of catalyst with a good thermal stability and high Bronsted acidity in order to replace common mineral acids. However, it has low specific surface area (1-5 m²/g). Therefore, the possibility of PRGO as a catalytic support for HPW is investigated due to its high surface area (2630 m²/g) and good thermal stability. The synthesis of HPW-GO catalyst is prepared using microwave and …

The Study Of Au(Iii) Compounds And Their Interaction With Zinc Finger Proteins, Sarah Spell

Theses and Dissertations

Gold compounds have been used in medicine dating back as early as 2500 BC. Over the years gold(I) and gold(III) compounds have been used and designed to target rheumatoid arthritis, cancer, and viral diseases. New drug targets have been found for gold compounds that give insight into their mechanisms of action. Here we focus on the synthesis of Au(III) compounds designed to selectively target zinc finger (ZF) proteins. ZF proteins exhibit a variety of functions, including transcription, DNA repair, and apoptosis. Displacement of the central zinc ion, along with mutation of coordinated amino acids can result in a loss of …

Approximate Quantum Trajectory Method For Modeling Chemical Reaction Dynamics: Application To Enzymatic Proton Transfer, James William Mazzuca

Theses and Dissertations

Molecular dynamics simulations, providing a detailed picture of the reaction mechanism, is an essential tool for theoretical and experimental chemists. In these simulations the nuclei are typically treated as classical particles, but under some conditions (low energies and temperatures, processes involving multiple electronic states) a classical description is inappropriate. Quantum effects of nuclear motion, such as tunneling and zero-point energy can play an important role in determining a reaction mechanism, yet exact quantum dynamics methods are limited to reactive systems of just 3-4 atoms. Central to this work is the development and implementations of an efficient trajectory-based methodology, in which …

Modified Seed Growth Of Iron Oxide Nanoparticles In Benzyl Alcohol: Magnetic Nanoparticles For Radio Frequency Hyperthermia Treatment Of Cancer, Stanley E. Gilliland Iii

Theses and Dissertations

Iron oxide nanoparticles have received sustained interest for biomedical applications as synthetic approaches are continually developed for precise control of nanoparticle properties. This thesis presents an investigation of parameters in the benzyl alcohol synthesis of iron oxide nanoparticles. A modified seed growth method was designed for obtaining optimal nanoparticle properties for magnetic fluid hyperthermia. With a one or two addition process, iron oxide nanoparticles were produced with crystallite sizes ranging from 5-20 nm using only benzyl alcohol and iron precursor. The effects of reaction environment, temperature, concentration, and modified seed growth parameters were investigated to obtain precise control over properties …

Fabrication And Characterization Of High Surface Area Gold Electrodes, Madhura S. Damle

Theses and Dissertations

High surface area gold electrodes are very good substrates for biosensors, catalysis and drug delivery. Their performance is characterized by good sensitivity, low detection limit and high signal. As a result, extensive research is being carried out in this field using different approaches of fabrication to generate high surface area porous electrodes of different morphology, pore size and structure. The morphology of the electrodes can be changed based on whether the approach involves a template or not, types of metal deposition, method and time of dealloying etc. The deposition of metal can be carried out using various approaches such as …

Traceability Implementation In Organic Farming: Case Study, Chamomile Tea Production, Shaima Ibrahim

Theses and Dissertations

Implementing a traceability plan in an herbal production plant is a complex task. In this study an attempt to integrate food safety, quality and traceability through the different stages of the organic German Chamomile (Matricaria recutita) production chain was made. First, all the current relevant international laws, regulations and standards regarding traceability, safety and quality, with emphasis on how and why they are necessary for any food production chain, were set forward. Second, physico-chemical and microbiological analyses were run throughout the different processing stages of production, for four different Chamomile batches produced over the same season using the same farming …

Structure-Property Relationships In Polybenzimidazole Materials For Gas Separation And Fuel Cell Applications, Xin Li

Theses and Dissertations

The central theme of my research lies in the investigation of novel polybenzimidazole (PBI)-based materials for different energy related applications ranging from proton exchange membrane fuel cells (PEMFC) to high temperature gas separation. With the aid of a deeper understanding of the structure-property relationships in this class of materials, a better control on PBI chemistry - from monomer structure to polymer morphology to membrane/film processing method was able to be performed in order to achieve greater performance in targeted applications.

In Chapter 1, the overall background of two energy related applications - fuel cells and gas separation was first introduced …