Chemistry Commons^™

Surface Modification Of Core-Shell Silver-Titania Nanocomposites With Copper Bipyridine–Phosphonates And Studies On Ag@Tio₂ Mediated Degradation Of Organophosphates, Somayeh Talebzadeh Farooji

Theses and Dissertations

Silver nanoparticles, coated with a titania shell were prepared and were shown to be catalytically active for the rapid degradation of organothiophosphate methyl parathion (MeP). Formation of the degradation product, p-nitrophenolate (PNP) was monitored as a function of pH, using UV-Vis spectroscopy, and 31P NMR spectroscopy confirmed the hydrolysis is the predominant pathway for substrate breakdown under non-photocatalytic degradation. We have demonstrated that the unique combination of TiO2 and silver nanoparticles is required for catalytic hydrolysis with good reproducibility. This work represents the first example of MeP degradation using TiO2 doped with AgNP under mild and ambient conditions. It is …

Metastable-State Photoacids And The Related Photo-Responsive Polymers, Zhuozhi Wang

Theses and Dissertations

Metastable-state photoacid is a type of photo-sensitive compounds that can release large amount of protons reversibly upon visible-light irradiation. Since being developed by our group in 2011, metastable-state photoacid has been utilized to develop many applications that involve controlling proton transfer processes. Since proton transfer process is one of the most common processes in nature, metastable-state photoacid is a powerful tool to control various processes with light. A introduction of metastable state photoacid is described in Chapter 1. In Chapter 2, metastable-state photoacids with different substituents were designed to study the relationship between their structures and physicochemical properties. In Chapter …

Oxidation Of Dibenzothiophene To Dibenzothiophene-Sufone Using A Molybdenum (Vi) Oxide Catalyst: A Kinetic Study Testing Solvent Dependency And Mole Ratio Efficiency, Tomas Trevino Jr.

Theses and Dissertations

Oxidative desulfurization (ODS) is currently a solution to hydrodesulphurization. Currently, industrial usage of hydrodesulphurization (HDS) is the common source for petroleum purification. Unfortunately, HDS comes with environmental and economical ramifications. Due to the problems and potential hazards being presented with HDS, ODS has become a topic of interest in research development. A kinetic study using molybdenum (VI) oxide as a catalyst was used in oxidative desulfurization. Factors such as mole ratio and solvent dependency were tested for efficiency. As activation energy was calculated to show maximum efficiency with respect to temperature and concentration. Gas Chromatography, FT-IR, and Mass Spectroscopy were …

Remediation Of Lead And Copper Ions From Water Solutions Using Transition Metal Sulfides, Jesus M. Cantu Jr.

Theses and Dissertations

Heavy metal contamination in water solutions has been a major concern since many transition metals don’t play a role in any biological function and are actually detrimental to human health. There have been several techniques that have been implemented for the remediation of heavy metal contaminants. For this project, three metal sulfides—Fe7S8, ZnS, TiS 2—were synthesized and studied for their capabilities to remove Pb(II) and Cu(II) from water solutions. Several parameters were investigated to determine the effects of pH, time, temperature, binding capacities, and interfering ions. The room temperature adsorption capacities ranged 6.23–333.3 mg/g for Pb(II) and 1.31–250 mg/g for …

Remediation Of Trivalent And Hexavalent Chromium Ions From Aqueous Solutions Using Titanium Dioxide Polymorphs, Yvette Cantu

Theses and Dissertations

Three titanium dioxide (TiO2) polymorphs were synthesized and used for the removal of chromium (III) and chromium (VI) from aqueous solutions. Various solution parameters were studied to determine the effects of pH, temperature, time, possible interfering ions, and capacities on the binding of Cr(III) and Cr(VI) to all three polymorphs. pH assays determined the optimum pH for the binding of both Cr(III) and Cr(VI) to each polymorph. Adsorption isotherms determined that the adsorption of Cr(III) was non-spontaneous for the three polymorphs with ΔG values ranging from 6.03 to 12.89 kJ/mol. Furthermore, the binding of Cr(VI) to anatase was also non-spontaneous …

Synthesis Of Tetraethyl ((2-Amino-1,4-Phenylene)Bis(Methylene)) Bis(Phosphonate): An Intermediate In The Synthesis Of Amino-Substituted Conjugated Materials, Ariel Ivan Torres Burgueno

Theses and Dissertations

Discussed here are the syntheses of the phosphonate precursors for the Wittig-Horner synthesis of poly-phenylene vinylene (PPV) and distyrylbenzene (DSB) derivatives and their respective distyrylbenzene analogs containing amino moieties. The synthesis of the different compounds was achieved through bromination, Michaelis-Arbuzov reaction, reduction of the nitro group with a commercial cobalt sulfide catalyst and sodium borohydride. Preliminary evidence for the synthesis of amino substituted distyrylbenzene and of nitro/alkoxy substituted poly(p-phenylene vinylene) was obtained. Characterization of the products was performed by 1H-NMR. Preliminary results of the synthesis of a novel amino-substituted distyrylbenzene (DSB) are presented. The luminescence of the new DSB was …

5-Oxo-Ete Antagonists In Allergic Disease; Design And Synthesis Of Affinity Chromatography Ligand For 5-Hedh; And Synthesis Of Isoprostanes As An Index For The Diagnosis In Alzheimer’S Disease, Qiuji Ye

Theses and Dissertations

Arachidonic acid (AA, 4, Figure 1) is a 20:4 (ω-6) fatty acid with a 20-carbon chain and four cis-double bonds, and the esterified form of AA in phospholipids can be enzymatically liberated by phospholipases (PL) and subsequently metabolized into a variety of physiologically important mediators known as eicosanoids (Figure 2). One of the most important eicosanoids is 5-oxo-6,8,11,14-eicosatetraenoic acid (5-oxo-ETE, 17). The 5-oxo-ETE (17) is the most known potent chemotactic factors for human eosinophils, and it can stimulate the late-phase asthma attacks.¹ To determine how the biosynthesis of 5-oxo-ETE is regulated, so as to determine its pathophysiological roles in the …

Interaction Between Fragments Of Tau Protein Investigated By Force Spectroscopy Using Afm, Anad Mohamed Afhaima

Theses and Dissertations

Over the last couple of decades, there has been rapidly growing interest in research of natively unfolded proteins. Some proteins from this group are implicated in a number of neurodegenerative diseases. One group of neurodegenerative diseases, taupathies, is associated with tau protein. A number of biophysical and spectroscopic studies have revealed that tau protein can expand to a largely extended state and to transition rapidly between many different conformations. Although many of the techniques that elucidate structure of macromolecules have provided important information about the folded states of proteins, important information about the transition between the extended conformation states remain …

Metastable-State Nh Photoacids And Organic Photo Carbon Monoxide Releasing Materials, Aluthwatte Rallage Nawodi Madhusanka Abeyrathna

Theses and Dissertations

The recently discovered metastable-state photoacids (mPAHs) can produce a large proton concentration with high efficiency and good reversibility upon irradiation with visible light with moderate intensity. Therefore, mPAHs can be conveniently incorporated in to different systems to control various proton-transfer processes. Recently, several applications of mPAHs have been demonstrated. However, none of the previously reported mPAHs can function at a pH 7.4. Thus, biological applications of mPAHs are limited. In this work, mPAHs that can reversibly release a proton in PBS buffer (pH = 7.4) under visible light are designed and synthesized. NH-PAH-1 is the first of this type of …

Hydrodesulfurization Of Dibenzothiophene Using Lanthanum Doped Comos2, Carolina Valdes Bracamontes

Theses and Dissertations

Hydrodesulfurization (HDS) is a technique used in petrochemical industry for the removal of sulfur from crude oil. Using dibenzothiophene (DBT) as a target molecule and CoMoS2 catalysts doped with various concentrations of lanthanum were studied for catalytic activity in the removal of DBT from solution. Catalysts were synthesized using ammonium tetrathiomolydate, cobalt chloride and lanthanum nitrate under a solvothermal decomposition in decalin at 350 °C with H2 gas at 160 psi. To evaluate decomposition effects, a second set of catalyst precursors were decomposed in a tube furnace at 450 °C under a constant flow of 10%/90% H2/Ar. Characterizations of the …

Capacity Of Human Immunodeficiency Virus Targeting Chimeric Antigen Receptor T Cells To Eliminate Follicular Dendritic Cells Bearing Human Immunodeficiency Virus Immune Complexes, Matthew T. Ollerton

Theses and Dissertations

An important obstacle to a functional cure for HIV/AIDS is the persistence of viral reservoirs found throughout the body in various cells and tissues. Reservoirs can be latently infected cells, or in the case of follicular dendritic cells (FDC), non-infected cells that trap infectious virus on their surface through immune complexes (HIV-IC). Although several strategies have been employed to target and eliminate viral reservoirs, they are short-lived and ineffective. In an attempt to provide a long-term approach, chimeric antigen receptor T (CAR-T) cells were designed to eliminate native HIV on FDCs. Although effective at eliminating HIV-infected cells, and halting spreading …

Substituted Hydroxylamines As Nitrogen Transfer Reagents: Direct Synthetic Pathways To Structurally Rich Heteroatomic Scaffolds, Dylan John Quinn

Theses and Dissertations

Nitrogen is found in virtually all valuable chemical compounds. The abundance of atmospheric nitrogen however, is rendered inaccessible because of the strong N-N triple bond, ultimately preventing its practical utilization in synthetic organic synthesis. The development of powerful nitrogen transfer reagents, such as substituted hydroxylamine derivatives, have played an important role in the introduction of nitrogen into valuable chemical scaffolding.

Herein is reported the methodological development of synthetic nitrogen placement into a range of valuable heteroatomic compounds. This work shows that O-Substituted Hydroxylamine can be used to furnish small heteroatomic compounds, particularly nitriles. Whereas, N-Substituted Hydroxylamine can be employed to …

Kinetic Characterization Of Listeria Monocytogenes 2-C- Methyl-D-Erythritol 4-Phosphate Cytidylyltransferase ( Cms ) Enzymes Using High Performance Liquid Chromatography ( Hplc ), Mark Oblazny

Theses and Dissertations

Infectious diseases, with increasing prevalence of antibiotic resistant bacteria, coupled with the declining rate in discovery of antimicrobial agents, impose one of the most significant threats to human health. Here we identify 2-C-methyl-D-erythritol 4-phosphate cytidylyltransferase (CMS) as a valid target for antibiotic development which is an enzyme in pathogenic organisms that leads to the biosynthesis of isoprene precursor molecules. Isoprene molecules are one of nature’s most common building blocks that are vital to many biological metabolic processes and are synthesized via the mevalonic acid dependent (MVA), or methylerythritol phosphate (MEP) pathway. Vertebrates utilize the MVA pathway, while many pathogenic bacteria …

The Biochemical Assessment Of Two Secreted Acid Phosphatases From Leishmania Tarentolae, Their Response To Electric Fields, Glycosidase Incubation, And / Or Vanadium, Benjamin M. Dorsey

Theses and Dissertations

Leishmaniasis, as defined by the Center for Disease Control and Prevention, is a neglected tropical disease with 1.6 million new cases reported each year. However, there is yet to be safe, effective, and affordable treatments provided to those affected by this disease1. Still underappreciated as a potential pharmaceutical targets, especially for cutaneous leishmaniasis infections, are the two isozymes of secreted acid phosphatase (SAP); secreted acid phosphatase 1 (SAP1) and secreted acid phosphatase 2 (SAP2). These enzymes are involved in the survival of the parasite in the sand fly vector, and the prevention of host macrophages from forming parasitophorous vacuole and …

Fermenting Solutions To New World Problems: Bioremediation Of Blue Agave And Cocoa Pod Wastes, Daniel Hart

Theses and Dissertations

Waste, minimizing it, and maximizing profit from it are major foci of most agricultural production processes today. Waste from two major production processes, namely tequila production and cocoa production, share several characteristics. Both these processes are still carried out as they have been for hundreds of years. They are both relatively concentrated in location; all tequila is produced in a small region of Mexico while cocoa pods only grow in tropical environments within 18° of the equator. In addition, both processes used to produce these commodities remain fairly inefficient; they generate huge amounts of waste that goes mostly unused. With …

Development Of Novel Alkaloid Derivatives For The Treatment Of Chronic Myeloid Leukemia, Lindsay Michelle Renn

Theses and Dissertations

The majority of chronic myeloid leukemia (CML) patients can be treated with and respond to imatinib mesylate (Gleevec). Imatinib is known to inhibit BCR-ABLl kinase activity, and is effective for the treatment of the majority of CML patients. Multiple mutations have been found in patients resistant to imatinib treatment, including many located in the BCR-ABLl tyrosine kinase domain (e.g. E255K and T315I). Matrine is a bioactive alkaloid from Sophora flavescens and has been shown to inhibit several types of cancers and is used in Chinese medicine. The goal of this study is to develop new matrine derivatives that inhibit growth …

Semiconductor Terahertz Electronics And Novel High-Speed Single-Shot Measurements, Parker Dean Salmans

Theses and Dissertations

Ultrafast spectroscopy is used to study essential characteristics of solid-state materials. We use ultrafast techniques to study semiconductors at THz frequencies, as well as demonstrate new single-shot measurement techniques. The future of electronics is in the THz regime. We study a crucial characteristic of semiconductors used in devices: the critical field at which the material becomes conductive. GaAs is a promising semiconductor for high-speed devices, and we use enhanced THz electric fields to measure the critical fields at 0.7, 0.9, 1.1, and 1.5 THz frequencies. Single-shot spectroscopy is a technique used to measure ultrafast time scale laser pulses. We show …

Electrokinetically Operated Integrated Microfluidic Devices For Preterm Birth Biomarker Analysis, Mukul Sonker

Theses and Dissertations

Microfluidics is a vibrant and expanding field that has the potential for solving many analytical challenges. Microfluidics shows promise to provide rapid, inexpensive, efficient, and portable diagnostic solutions that can be used in resource-limited settings. Microfluidic devices have gained immense interest as diagnostic tools for various diseases through biomarker analysis. My dissertation work focuses on developing electrokinetically operated integrated microfluidic devices for the analysis of biomarkers indicative of preterm birth risk. Preterm birth (PTB), a birth prior to 37 weeks of gestation, is the most common complication of pregnancy and the leading cause of neonatal deaths and newborn illnesses. In …

Miniaturization Of Linear Ion Traps And Ion Motion Study In A Toroidal Ion Trap Mass Analyzer, Ailin Li

Theses and Dissertations

I describe the miniaturization of a linear-type ion trap mass spectrometer for possible applications in portable chemical analysis, and demonstrate the advantages of using lithographically patterned electrode plates in realizing an ion trap with dimension r₀ less than 1 mm. The focus of the work was to demonstrate the viability and feasibility of the patterned electrode approach to trap miniaturization, and also to discover potential obstacles to its use. Planar ceramic substrates were patterned with metal electrodes using photolithography. Plates that were originally used in a linear trap with a half-spacing (r₀) of 2.19 mm were positioned …

Biocidal Defeat Agents Produced By Silver-Iodine Nanoenergetic Gas Generators, Ivan Davila

Theses and Dissertations

Nanostructured aluminum (Al), iodine pentoxide (I2O5) nano-rods, and silver oxide (Ag2O) nanoparticles, (Al-I2O5-Ag 2O) were used to compose the ternary thermite composition that serves as a Nanoenergetic Gas Generator (NGG). This composition produces biocidal gases giving the mixture the ability to destroy highly pathogenic microorganisms or bacteria. The dissemination of the biocidal gas in combustion chamber was observed using a high-speed camera. The testing of NGG combustion process against the living Escherichia coli (E.coli) K-12 strain cells, that were cultivated/placed on the sample/chamber surfaces, demonstrated that iodine and silver atoms clouds were deposited to the bacteria surface. The 10/75/15 wt …

Ion Trap Miniaturization Considerations: Space-Charge Effects In Cylindrical Ion Traps And Misalignment Effects In A Two-Plate Linear Ion Trap, Yuan Tian

Theses and Dissertations

Portable mass spectrometers provide convenience for applications where conventional mass spectrometers are not suitable. However, a series of miniaturization issues show up in small mass spectrometers, specifically mass analyzers, that need to be thoroughly addressed before further miniaturization. The work in this dissertation focuses on miniaturization issues of ion trap mass analyzers. Space-charge is one of the major issues in small ion traps affecting their analytical performance. It limits ion trapping capacity when ion-ion repulsion causes spreading of a packet of ions. Simulation studies on the relationship between different trap dimensions and trapping capacity was done on a geometry-optimized cylindrical …

Microwave-Promoted Iminyl Radical Cyclizations For The Synthesis Of Azaheterocycles And The Total Synthesis Of Yaku'amide A, Yu Cai

Theses and Dissertations

Two different research projects are described in this dissertation. The first one focuses on microwave-promoted iminyl radical cyclization for the formation of azaheterocycles which are embedded within numerous pharmaceuticals and biologically active natural products (such as clindamycin, eletriptan, moxiflaxin, etc.). We are quite interested in this project because of the significance of nitrogen-containing heterocycles as pharmaceuticals and organocatalysts combined with the need for safe, simple, and economical means of constructing them. We have successfully developed an efficient one-step synthesis of 2-acylpyrroles and diastereoselective dihydropyrroles from readily available oxime ether substrates. This remarkably efficient and environmentally friendly methodology should be useful …

Post-Translational Regulation Of Superoxide Dismutase 1 (Sod1): The Effect Of K122 Acylation On Sod1'S Metabolic Activity, Courtney Jean Banks

Theses and Dissertations

Many mutations in superoxide dismutase 1 (SOD1) cause destabilization and misfolding of the protein and are implicated in amyotrophic lateral sclerosis. Likewise, a few post-translational modifications (PTMs) on SOD1 have been shown to cause the same phenotype. However, relatively few PTMs on SOD1 have been studied in depth and, in particular, very few studies have demonstrated how these PTMs affect SOD1's various biological roles. SOD1 is traditionally known for its role in reactive oxygen species (ROS)-scavenging but has also been found to have a few other biological roles, including transcription factor activity to promote genomic stability, preservation of cytoskeletal activity, …

Advancements In The Understanding Of Nonlinear Optics And Their Use In Material Analysis, Shawn C. Averett

Theses and Dissertations

Adhesion, heterogeneous catalysis, electrochemistry, and many other important processes and properties are driven by interactions at surfaces and interfaces. Vibrational sum frequency generation spectroscopy (VSFG) is an increasingly popular analytical technique because it can provide information about the nature and physical orientation of functional groups at these surfaces and interfaces. Analysis of VSFG data can be complicated by the presence of SFG signal that is not associated with a resonant vibration. This nonresonant sum frequency generation (NR-SFG) signal can interfere with the resonant signal and influence the detected spectrum. Methods have been developed to remove NR-SFG signal; however, these methods …

Role Of Molecular Chaperonin Cct And Its Co-Chaperone Phlp1 In The Assembly Of Mtor Complexes, Madhura Vinayak Dhavale

Theses and Dissertations

mTOR is the central kinase in biochemical pathways that regulate cellular growth, protein synthesis and cell survival. Deregulation of mTOR signaling results in uncontrolled cell proliferation and hence is implicated in various cancers and autoimmune diseases. mTOR functions through two distinct signaling complexes, called mTORC1 and mTORC2. CCT is a cytosolic chaperonin that assists in folding of several protein substrates. In these studies, we have identified two components of the mTOR complexes, mLST8 and Raptor, as substrates of CCT. We have performed biochemical and signaling studies which indicate that CCT is involved in assembly and signaling of mTOR complexes by …

Microwave-Promoted Iminyl Radical Fragmentations: A Practical And Efficient Method Of Functionalization, Mary Megan Jackman

Theses and Dissertations

We report a novel fragmentation and functionalization method using a cyclic iminyl radical. Formation of this radical occurs by microwave heating under mild conditions and short reaction times. The reaction avoids the use of explosive or toxic radical initiators and propagating agents. This reaction is versatile, with the ability to install two functional groups that are ultimately derived from a ketone in the substrate precursor. A variety of radical traps capable of forming both carbon-carbon bonds and carbon-heteroatom bonds have been tested, and the products are obtained in good yields. We demonstrate the power of this reaction by functionalizing complex …

Electrophilic Catalysis Using Heterobimetallic Complexes, Whitney Kaye Walker

Theses and Dissertations

Conventional ligand design in transition metal catalysis capitalizes on the ability of phosphorous, nitrogen, carbon, oxygen, and sulfur-based donors to modify the steric and electronic properties of a reactive metal center. Heterobimetallic transition metal complexes that contain a dative metal-metal bond provide a unique approach to ligand design where the reactivity of the metal center can be modified by metal-metal electronic communication. Our laboratory is interested in using the unique properties of heterobimetallic complexes to address significant limitations in current transition metal catalysis. My PhD work has focused on the ability of early/late transition metal heterobimetallic complexes to facilitate catalysis …

Acylation Of Superoxide Dismutase 1 (Sod1) At K122 Alters Sod1 Localization And Sod1-Mediated Inhibition Of Mitochondrial Respiration, Nathan William Rodriguez

Theses and Dissertations

Cu/Zn Superoxide Dismutase (SOD1), is a ubiquitous antioxidant enzyme with several emerging roles outside of its canonical function. SOD1 is also emerging in central roles in cancer and neurodegenerative pathologies. Little is known about SOD1 regulation, particularly at a post-translational level. Post-translational modifications (PTMs) play an important role in enabling proteins to rapidly respond to their environment. Therefore, identifying specific PTMs involved in protein regulation represents a powerful opportunity to interfere with any associated pathologies. This work employs proteomics to identify mechanisms of post-translation regulation on cell survival signaling proteins. We focused on SOD1, which protects cells from oxidative stress. …

Fundamental Studies And Applications Of Ambient Plasma Ionization Sources For Mass Spectrometry, Wade C. Ellis

Theses and Dissertations

The field of ambient desorption/ionization mass spectrometry (ADI-MS) has existed for over a decade. ADI-MS is a technique that offers benefits including fast analysis time, simple ionization sources that are easily constructed, and little to no required sample preparation. The research presented here describes efforts to better understand plasma-based ADI-MS sources and to explore the use of hydrogen-doped plasma gases with these sources. The use of hydrogen-doped argon (H₂/Ar) and hydrogen-doped helium (H₂/He) as plasma gases for a dielectric barrier discharge (DBD) and an AC glow discharge is presented first. When using the DBD, the intensity …

Ion Transport In A Commercial Icp-Ms, Jessica Joline Larsen

Theses and Dissertations

The performance of an inductively coupled plasma mass spectrometer, ICP-MS, depends on the instrument's ability to transport sample ions through the vacuum interface and focus the ions into a well-defined beam that will eventually reach the mass analyzer. In this study two main experiments were performed on the Perkin Elmer NexION 300S, a commercial ICP-MS. First, planar laser-induced fluorescence images were taken of the ion beam in a working instrument downstream from a unique quadrupole ion deflector. The images showed the ability of the instrument design to focus the ions in the ion beam. Second, laser-induced fluorescence was used to …