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Quantitation Of Yohimbine Utilizing Capillary Electrophoresis. Method Development Through Statistical Design., Jonathan Cooper

Theses

In an effort to combat the rising cost of health care in the United States by encouraging preventative and self-care, the federal government passed the Dietary Supplement Health Education Act of 1994. This act essentially deregulated the natural product market allowing herbs, including yohimbine, to be sold over the counter without undergoing the same strict evaluation as a traditional synthetic drug candidate. As the full potential of these natural products is realized, including possible harmful side effects, a need arises for the identification and quantitation of the active components from commercial preparations. Commercial samples were qualitatively and quantitatively analyzed for …

Preparation And Characterization Of A Site-Directed Mutant Of Escherichia Coli L-Threonine Dehydrogenase, Qian Zhou

Theses

Threonine dehydrogenase from E.coli is a member of the medium-chain, Zn2+-containing alcohol dehydrogenase family. A site-directed mutant of theronine dehydrogenase was prepared at position 88 by replacing the native glutamate with cysteine using polymerase chain reaction. The mutated enzyme, designated TDH E88C, was expressed and purified to homogeneity in a three-step chromatographic procedure. The activity of the mutant after each step of purification was determined by a specific assay. Both the total activity and the specific activity of TDH E99C were significantly decreased compared to the wild-type TDH. The mutant enzyme was not sufficiently stable to obtain reliable Vmax or …

The Use Of Silica And Alumina To Catalyze The Addition Of Hydrogen Chloride To Alkenes, Ying Liu

Theses

The use of pre-heated silica gel and alumina along with a chlorinating agent, generates HC1 in situ, which has been found to add to norbornadiene ( IX ). Treated in this fashion, norbornadiene readily results in the formation of two isomers, exo-5- chloronorbornene ( XI ) and 3-chloronotricyclene ( XII ) at room temperature in methylene chloride, with ejco-5-chloronorbornene being the predominant product ( 70% 1% ). In promoting the hydrohalogenation reaction, silica gel was found to be less efficient compared to alumina, but undesired diadducts appeared to be less prominent when silica gel rather than alumina was used. Deuterated …

Addition Of Chelated Trivalent Cations To Solutions Of The Polymer Sodium Carboxymethylcellulose (Cmc), Deborah Hawkins

Theses

This study was comprised of two related projects: a viscosity variability study and a trivalent cation study. For the first study, the dependence of viscosity of solutions of the polymer sodium carboxymethylcellulose (CMC) on temperature was quantitatively determined so that the viscosity measurements from four sets of viscosity versus age of solution data could be normalized. The four sets of age of solution data were obtained for two solutions containing Al cation and for two solutions containing Mg cation. The temperature normalization procedure proved viable. Factoring out the variability due to temperature led to a decrease in overall variability of …

Zirconium Pendent Poly(Amic Acid) And Polyimide Based On 3,4'-Oda And Odpa, Kanwen Yang

Theses

To improve the materials' resistance to atomic oxygen, the aromatic polyamic acid based on 4,4'-oxydiphthalic anhydride (ODPA), 3,4'-oxydianiline (ODA) and mellitic dianhydride (MADA) was synthesized and allowed to react with the complex (4- amino-N,N ' -disalicylidene- 1 ,2-phenylenediaminato)(N,N ' -disalicylidene- 1 phenylenediaminato)zirconium (IV), Zr (adsp)(dsp), in the presence of dicyclohexylcarbodiimide (DCC). The resulting Zr pendent polyamide acid was cast onto glass substrates, and thermally imidized. The synthesized polyamic acids and polyimides were characterized by Thin Layer Chromatography (TLC), Fourier Transform Infrared (FTIR), Proton Nuclear Magnetic Resonance ('H NMR) and Gel Permeation Chromatography (GPC), along with Thermogravimetric Analysis (TGA) and Differential …

A Combinatorial Library Of (Alpha)-Amide Sulfone Derivatives Of Phenylalanine, Andrew Hoteling

Theses

The synthesis of a combinatorial library of a-amide sulfone derivatives of phenylalanine was achieved using a solid phase synthesis approach. A multistep reaction sequence was used to introduce two sites of diversity, beginning with phenylalanine as the template attached to ArgoGel-Wang resin. The initial solid phase reaction studies were monitored using nanoprobe NMR and the reaction progress for library synthesis was monitored using a duplicate of one of library members as an analytical control sample. The complete library was evaluated by HPLC-DAD and HPLC-MS analysis of cleaved products. Selected members of the library were characterized using FAB MS/MS and !H …

The Laser Optogalvanic Effect In Radio Frequency Plasma: Applications In Analytical Chemistry., Xuan Yao

LSU Historical Dissertations and Theses

The laser optogalvanic effect (LOGE) is the change of electrical impedance of a plasma produced by resonant absorption of laser radiation. Selected excitations can be used to detect specific species by tuning the laser to an appropriate wavelength. For optimum utilization of LOGE as a detection tool, one must understand the temporal profile of the LOGE signal in terms of the various processes occurring in the plasma. In this work, the characteristics of the LOGE signal and the potential applications of laser optogalvanic spectroscopy (LOGS) have been investigated. First, by analyzing the LOGE signal profiles of the neon excitations 1s2,4→2p1,3, …

Spectroscopic Studies Of Solid State Cyclodextrin Complexation Reactions With Various Guest Molecules., Michelle Butterfield Young

LSU Historical Dissertations and Theses

The research presented in this dissertation involves spectroscopic studies of cyclodextrin complexation reactions with various guest molecules. Chapter 1 provides an introduction that forms the basis for the remaining chapters. The topics covered in the introduction include the structures and properties of cyclodextrins with a brief section specifically dedicated to solid cyclodextrin. In addition, the environmental applications of cyclodextrins are discussed. The last part of the introduction concerns the theory and applications of fluorescence spectroscopy. In Chapter 2, the extraction of volatile polycyclic aromatic hydrocarbons (PAHs) from air by use of solid cyclodextrin is presented. Naphthalene was chosen as the …

Mass Spectrometry Of Biomolecules. Part A: Gas-Phase Thermochemical And Structure Determinations Of Mononucleotides. Part B: Analysis Of Hydrophobic Peptides And Proteins By Matrix -Assisted Laser Desorption /Ionization Time -Of -Flight Mass Spectrometry., Kari Beth Green-Church

LSU Historical Dissertations and Theses

The use of mass spectrometry for thermochemical and structural determinations of mononucleotides is presented in Part A of this work, and the analysis of hydrophobic peptides and proteins are presented in Part B of this work. The goal of Part A is to examine thermochemical and structural properties of (deoxy)nucleoside 5'- and 3'-monophosphates. Part A consists of three groups of experiments. The first set of experiments utilized the kinetic method with a fast-atom bombardment source and a double focusing sector mass analyzer. Conformational analysis and semi-empirical calculations of mononucleotides were performed for the second set of experiments. The third set …

Synthesis, Thermodynamic Stability And Enzymic Behavior Of Oligonucleotides Containing Pyrazole Nucleobase Analogs., Andrea Sapp Saurage

LSU Historical Dissertations and Theses

Non-hydrogen bonding nucleosides with iodo, nitro, propynyl and thiazolyl substituted at the 4-position of pyrazole were prepared. These nucleosides were converted to their corresponding nucleoside phosphoramidites and incorporated into a series of complementary oligonucleotides in order to determine the effect that varying size, charge distribution and polarizability has on duplex stability and structure. The self-complementary Dickerson dodecamer sequence 5'-CGCXAATTYGCG-3', as well as the non-self complementary sequence 5'-CAAAATGGTGGCCAAGT-3 ' previously investigated by Brown, were used to determine the duplex stabilization and thermodynamic consequences of placing 5-nitroindole and 4-substituted pyrazole nucleosides across from each natural base. In the pyrazole series, the largest …

The Characterization Of Oligonucleotides And Nucleic Acids Using Ribonuclease H And Mass Spectrometry., Lenore Marie Polo

LSU Historical Dissertations and Theses

The use of mass spectrometry for the characterization of nucleic acids is presented in this work. One area of research was aimed at developing a method for the characterization of pseudouridine (Psi) containing samples derivatized with N-cyclohexyl-N' -beta-(4-methylmorpholinium)methylcarbodiimide (CMC). These experiments consisted of the derivatization of a tRNA molecule with CMC followed by analysis of the sample using polyacrylamide gel electrophoresis and mass spectrometry. Mass spectrometric analysis of the sample revealed that the derivatization of the sample was occurring to generate a species with one CMC group. This data is significant because it demonstrates that the comparably small mass shift …

Preparation And Characterization Of Derivatized Microparticles Immobilized In Hydrogel Membranes For Optical Chemical Sensing Based On Polymer Swelling, Eric William Miele

Doctoral Dissertations

Hydrogel membranes containing aminated microparticles have been investigated for reflectance based optical sensing. The membranes were evaluated by UV/Vis spectrophotometry, for potential use in a remote distributive fiber optic chemical sensor. This work describes efforts for improving the signal and decreasing the overall response time of the membranes. The microparticles were prepared by dispersion and seeded emulsion polymerization techniques. The microparticles were derivatized to introduce pH sensitivity. The hydrogel membranes containing swellable microparticles are turbid. Scattering occurs at the microparticle-hydrogel interface and is based on refractive index changes accompanying polymer swelling. The particles swell in response to hydrogen ion concentration, …

Functional Characterization Of The Ccr4-Not Transcriptional Regulatory Complex, Vasudeo Badarinarayana

Doctoral Dissertations

The CCR4-NOT transcriptional regulatory complex affects expression of a number of genes both positively and negatively. This study demonstrates that the CCR4-NOT complex functionally and physically interacts with TBP and TAFs. Firstly, mutations in CCR4, NOT4, and NOT5 suppressed the his4-912 delta insertion by a mechanism similar to that observed for the defective TBP allele spt15-122. This mechanism appeared to involve stabilization of TBP binding to a specific non-consensus TATA sequence, CATAAA, in the his4-912 delta element. Secondly, using modified HIS3 promoter derivatives containing specific mutations within the TATA sequence, it was found that the NOT proteins were general repressors …

The Chain Extension Of Beta-Keto Phosphonates And The Synthesis Of Polycyclopropanes, Christopher Andrew Verbicky

Doctoral Dissertations

A series of beta-keto phosphonates was prepared and their reactivity with the Furukawa-modified Simmons-Smith zinc carbenoid was studied. Various functionality was incorporated into these molecules in efforts to broaden the scope of the zinc-mediated chain extension reaction. The mechanism of the chain extension of dimethyl (2-oxopropyl)phosphonate was probed by nuclear magnetic resonance in efforts to observe key intermediates of these reactions.

The stereochemistry of bis-, tris-, and tetrakis-cyclopropanes was confirmed by a one directional asymmetric independent synthesis. Application of an olefin cross-metathesis reaction allowed vinyl tetrakis-cyclopropane to be elaborated into an advanced intermediate toward the preparation of FR-900848, a polycyclopropanated …

Vibrational Characterization Of A Series Of Aromatic Quinones, William J. Price

Electronic Theses and Dissertations

The vibrational characterization of a series of molecules: 1,4-anthracenedione, 5,14-pentacenedione, 6,15-hexacenedione, 8,13-benzo[a]naphthacenedione, 7-methyl-8,13-benzo[a]naphthacenedione has been carried out. The synthesis of these materials was carried out in the research laboratory of Dr. P. Dibble of the Department of Chemistry, University of Lethbridge, Lethbridge, Alberta, who provided to us a purified sample of each compound. The inelastic scattering was measured at 1064nm (FT-Raman) and the infrared absorption spectra were measured in the mid-infrared (300--3600 cm-1). The vibrational assignments of normal modes was assisted by semi-empirical quantum calculations with the AM1 and PM3 Hamiltonian. A high level ab initio computation for 5,14-pentacenedione is …

Interpenetrated And Interlocked Molecules Via Bis(Pyridinium)Ethanes., James Andrew. Wisner

Electronic Theses and Dissertations

This thesis deals with the synthesis of [2]pseudorotaxane, [2]-, and [3]rotaxane architectures utilizing bis(pyridinium)ethane dications and 24-membered crown ethers as templating agents. Eight bis(pyridinium)ethane dications 2a--h were synthesized and their complexation behaviour with six 24C8 derivatives 3a--f was examined. All the dications formed [2]pseudorotaxane geometries in solution with the crown ethers except for 2c which did not form a complex with any of 3a--f due to steric: constraints. Association constants for pseudorotaxane formation were determined by 1H NMR spectroscopy for all the complexes formed and the thermodynamics of formation of the pseudorotaxanes involving 2g and 3a--f . The crystal structures …

A Novel Approach To Dna Sequencing Employing Near -Ir Fluorescence Detection Coupled With Microscale Reaction Vessels With Capillary Gel Separations., Daryl Clifford Williams

LSU Historical Dissertations and Theses

Electropherograms of oligonucleotides labeled with near-IR fluorescent dyes, separated by capillary gel electrophoresis (CGE) and detected using an ultrasensitive near-IR fluorescence detection system will be presented. A Universal M13 sequencing primer was labeled on the 5' end with a near-IR dye containing an isothiocyanate functional group. Comparison of the on-column detection limits in capillary gel electrophoresis for the near-IR-labeled sequencing primer to that of a visible fluorescein-labeled primer indicated improved sensitivity for the near-IR case. The detection limit was found to be 3.4 x 10-20 moles (SNR = 3) for the near-IR-labeled primer while the on-column detection limit for the …

Precursors For Chemical And Photochemical Vapor Deposition Of Copper Metal., Alicia Marie James

LSU Historical Dissertations and Theses

The colorless square-planar cluster [CuN(SiMe3)2] 4, which contains four Cu(I) ions with four bridging amide groups, was studied as a precursor for chemical and photochemical vapor deposition of Cu metal. The cluster phosphoresces in CH2Cl2 solution and in the solid state at room temperature. Its electronic spectrum in CH 2Cl2 consists of two intense bands which are assigned to symmetry-allowed 3d → 4p transitions; the phosphorescence is also likely to be metal-centered. Solid [CuN(SiMe3)2]4 luminesces with approximately the same spectrum as that of the CH2Cl2 solutions. At 77 K, the solid-state luminescence red-shifts slightly. The emission lifetime in glassy Et2O …

Characterization Of The Arsenate Reductase Of Escherichia Coli Plasmid R773., Domenic. Perri

Electronic Theses and Dissertations

Bacterial resistance to toxic anions in Escherichia coli is carried on the R773 plasmid. The plasmid contains the ars operon, which encodes a group of proteins responsible for the extrusion of arsenicals and antimonials out of the cell. One of these proteins, ArsC, has been shown to reduce arsenate (AsO43-) to arsenite (AsO2-) prior to being transported out of the cell (Gladysheva et al., 1994). The protein requires glutathione (GSH) and glutaredoxin in order to reduce the toxic oxyanions. Circular dichroism experiments demonstrated that the secondary structure of ArsC changed marginally when either the substrate or product was present. The …

Asymmetric Reactions Of (Arene)Tricarbonylchromium Acetal Complexes., Maurice Kevin. Mckay

Electronic Theses and Dissertations

Chapter 1. The nucleophilic addition of alkyl and arylmetals to 1 was examined. When the reaction was mediated by Ti(O iPr)4, diastereomeric excesses ranged from 77% to >94%. X-ray crystallography suggested that the major diastereomer had the absolute configuration of S. Conjugate addition of alkylmetal nucleophiles was attempted on 2 and 3 without success. Chapter 2. The preparation of meta-disubstituted arenechromium tricarbonyl complexes was attempted. The initial phase of this research involved the directed ortho lithiation of 4, with thioether directing groups. In the case of the 4, carrying out the reaction in Et 20 led to the metallation in …

Mercury And Methylmercury In The Sediments Of Lake St. Clair (Michigan, Ontario)., Andrew David. Toms

Electronic Theses and Dissertations

Lake St. Clair is a wide, shallow lake situated midway between Lake Huron and Lake Erie. The lake basin has been a region of significant mercury contamination for several decades due to intense industrial activities, largely those of chlor-alkali plants located up-river. As the lake flushes very rapidly (t R ∼ 4 days), little sedimentation takes place, hence it was expected that most contaminants would be carried downstream to Lake Erie. The persistence of Hg in the upper sediments and biota indicates that some other processes may be at work. Inorganic mercury that has been released to the environment can …

Induced Pi-Facial Discrimination In The Alkylation Of Chiral Derivatives Of Glycine., Scott Owen. Peters

Electronic Theses and Dissertations

Part A. The alkylation trans 2-arylcyclohexyl hippurates with a series of electrophiles was examined. The reaction stereoselectivity varied from 46 to 81% depending on the steric and electronic nature of the electrophile when (Ar = phenyl). Higher stereoselectivity was observed when reacting electrophiles of increasing pi-character. When the chiral auxiliary contained a naphthyl group the stereoselectivity was >80% for every electrophile used. Part B. The alkylation of the trans 2-phenylcyclohexylamide of methyl glycinate with a series of electrophiles was examined. Incorporation of the chiral auxiliary on the amino terminus of the amino acid appears to induce good stereoselectivity only when …

Development Of Pseudostationary Phases For Separations In Electrokinetic Chromatography., Judson Leroy Haynes Iii

LSU Historical Dissertations and Theses

The research presented in this dissertation covers pseudo-stationary phase development for separations in electrokinetic chromatography (EKC). Micelles and cyclodextrins have traditionally served as the most popular pseudo-stationary phases (PSPs) used in EKC. However, the development and implementation of PSPs, which have improved properties over traditional ones, are necessary to extend the utility of electrokinetic chromatography. This dissertation covers research contributions, chapter by chapter, to the area of PSP development made by the author. In addition to this, Chapter 1 covers a brief history of chromatography and the fundamentals of capillary electrophoresis and EKC. The first pseudo-stationary phase developed was a …

Effects Of Substituent Substitution On A Bimetallic Hydroformylation Catalyst Based On A Tetraphosphine Ligand., Donna Kae Howell

LSU Historical Dissertations and Theses

The main concentration of this work was to further study the unusual catalytic activity and selectivity of the bimetallic hydroformylation catalyst based on the tetraphosphine ligand, et,ph-P4. This activity and selectivity are a product of both the rigid steric environment and the cooperativity between the two Rh metal centers. This project focused on probing both the mechanism employed by this system, and studying the effect of manipulation on the steric environment at the binding site. In situ spectroscopic methods have led to the formulation of a dicationic catalytic system. This is highly unusual in that all monometallic rhodium or cobalt …

Synthesis, Characterization, And Applications Of Chiral Polymeric Surfactants In Micellar Capillary Electrophoresis., Crystal Williams Harrell

LSU Historical Dissertations and Theses

Chirality is a characteristic of many synthetic and biological organic compounds. This property is particularly true in the pharmaceutical industry where a large number of drugs are marketed as racemates. One method used to monitor optical purity is capillary electrophoresis (CE). Chiral separation using CE is achieved by use of an immobilized chiral phase or through a chiral selector mobile phase additive. It is demonstrated and determined that chiral polymeric surfactants are more suitable for chiral separation in electrokinetic capillary chromatography (EKC) than conventional micelles. Polymeric surfactants eliminate the dynamic equilibrium that occurs in normal micelles, are more stable, rigid, …

Characterization Of Solidification/Stabilization Of Chromium Wastes In Cement Matrix., Aijun Zhang

LSU Historical Dissertations and Theses

A cement-based solidification/stabilization (S/S) system of Cr wastes treatment has been studied in this program. A combination of the two techniques; namely reduction of Cr(VI) to Cr(III) and simultaneous immobilization within a cement matrix, has been found to be effective and practical to treat Cr wastes. Cr(VI) can not be easily and effectively-immobilized in the S/S system unless being reduced to Cr(III). Ferrous compounds are used as reducing reagents. The reduction not only removes the toxic Cr(VI) species but also results in the low-solubility precipitation of (CrxFe 1-x) (OH)3(s) in the S/S system. Long-term and short-term samples were tested through …

Picosecond Resonance Raman Studies Of Interligand Electron Transfer Rates Of Ruthenium Polypyridal Complexes., Danny Ray Anderson

LSU Historical Dissertations and Theses

Interest in ruthenium polypyridal complexes stems from the metal-to-ligand charge transfer state (MLCT) that can be generated by photons of sufficient energy and the interligand electron transfer (ILET) that occurs after this state. Direct measurements using picosecond resonance Raman spectroscopy were made to determine the rates of ILET in a series of mixed ligand ruthenium polypyridal complexes. To perform these studies, a novel regenerative amplified Nd:YAG laser system had to be designed and built at Louisiana State University. Once this system was completed, a apparatus was designed for measuring transient absorption spectra in the 200--300 nm wavelength range on a …

Large Magnitude Sinusoidal Voltammetry For Reversible Electrochemical Reactions., Yide Chang

LSU Historical Dissertations and Theses

Sinusoidal voltammetry, the current response of a simple reversible electrochemical reaction under a large magnitude sinusoidal potential, is investigated in this work. The ferricyanide/ferrocyanide (Fe(CN)6-3/-4 ) redox couple at a platinum electrode, which is known to be reversible, was measured using sinusoidal potentials. Theoretical analyses, including computer-simulation of sinusoidal voltammetry at various excitation potentials, are also presented. The results obtained are in good agreement with the theoretical analysis. One remarkable advantage of sinusoidal voltammetry is that the charging current accompanying the electrode process, which is the most significant components of the noise at a fast potential scan, may be discriminated …

Application Of Barton Esters In Polymer Modification., Timothy S. Evenson

LSU Historical Dissertations and Theses

Esters of N-hydroxypyridine-2-thione, known as Barton esters, dissociate homolytically upon exposure to heat or light generating chain initiating acyloxy radicals and pyridine sulfide radicals that lead to 2,2'-dipyridyl disulfide. The dominant mode of Barton ester consumption is chain transfer, yielding pyridinesulfide end groups and acyloxy radicals. Thermolysis (80°C) or photolysis (25°C) of Barton esters initiated polymerization of styrene. The polymerization rate was found to be independent of Barton ester concentration. Chain transfer to initiator controls molecular weight; the chain transfer constants for phenyl Barton ester in styrene and acrylamide are 0.96 and 0.08 respectively. Polymer end-groups were identified as an …

In Situ Nmr And Ft-Ir Studies On A Bimetallic Hydroformylation Catalyst., Rhonda Carter Matthews

LSU Historical Dissertations and Theses

This work describes a study of the mechanism by which a unique homogeneous bimetallic hydroformylation catalyst based on two rhodium metal centers chelated and bridged by a special tetraphosphine ligand works via bimetallic cooperativity. Hydroformylation runs on this bimetallic system which indicate higher rates of production and higher linear to branched product regioselectivity relative to the commercial monometallic Rh/PPh3 catalyst make this system a viable candidate for an almost completely new and effective way of performing hydroformylation catalysis. Numerous complexes have been characterized by in situ FT-IR and NMR spectroscopic studies, as well as X-ray crystallography, and support the presence …