Digital Commons Network^™

Single Wall Carbon Nanotube-Nafion Composite Actuators, Brian Landi

Theses

Single wall carbon nanotube (SWNT)-Nafion composite actuators have been demonstrated for 0.1 - 18 %, w/w doping of purified SWNTs within the polymer matrix. The high purity SWNTs, >95%w/w, were prepared using thermal oxidation and acid treatments for both in-house synthesized pulse laser vaporization SWNTs and commercially obtained HiPco material. Characterization of the purified SWNTs was performed using thermogravimetric analysis, scanning electron microscopy, optical absorption and Raman spectroscopy. Homogeneous dispersions of SWNTs in a Nation polymer series were demonstrated using a combination of homogenization and high speed mixing techniques. Evaluation of SWNT-Nafion composites showed a "debundling" of the SWNT average …

Mechanism Of Toxt-Dependent Transcriptional Activation At The Vibrio Cholerae Tcpa Promoter, Robin R. Hulbert, Ronald K. Taylor

Dartmouth Scholarship

The AraC homolog ToxT coordinately regulates virulence gene expression in Vibrio cholerae. ToxT is required for transcriptional activation of the genes encoding cholera toxin and the toxin coregulated pilus, among others. In this work we focused on the interaction of ToxT with the tcpA promoter and investigated the mechanism of ToxT-dependent transcriptional activation at tcpA. Deletion analysis showed that a region from −95 to +2 was sufficient for ToxT binding and activation, both of which were simultaneously lost when the deletion was extended to −63. A collection of point mutations generated by error-prone PCR revealed two small regions required …

Study Of The Crystallization Behavior Of Polyethylene Oxide In Compatibilized And Uncompatibilized Polypropylene/Polyethylene Oxide Blends, Subramanian Iyer

Theses

Compatibilization of incompatible isotactic polypropylene (iPP)/polyethylene oxide (PEO) is studied with an emphasis on the crystallization behavior of polyethylene oxide. An attempt is made to correlate the crystallization data for PEO obtained from optical microscopy, differential scanning calorimetry, x-ray diffraction, infrared spectroscopy and dynamic mechanical analysis. PEO and iPP are incompatible in the temperature range -50C to 200C. iPP was used as the matrix while PEO was used as the dispersed phase. Experimental observations demonstrated that PEO underwent fractionated crystallization in the blends in the temperature region from -10C to 40C when cooled at a rate of 10C/min. PEO domains …

Solution-Phase Synthesis Of Tertiary Amines Via Reductive Amination-Alkylation With Ethyl P-Aminobenzoate, Kristen Harwood

Theses

Combinatorial chemistry is a means of rapidly generating large numbers of diverse molecules for the identification of novel molecular properties. This study will describe the attempt to synthesize, characterize and purify of a library of tertiary amine derivatives of ethyl p-aminobenzoate by solution-phase combinatorial synthesis. In this study, indirect reductive amination and subsequent alkylation of ethyl p-aminobenzoate is expected to produce thirty-five structurally related analogs. HPLC and LC-MS analysis of the resultant library however, shows that reduction of the imine intermediates with sodium triacetoxyborohydride also results in reduction of the ester functionality which prevents the subsequent alkylation reaction. A mechanism …

The Biophysical Basis Of Triplet Repeat Dna Expansion In Genetic Disease, Anthony M. Paiva

Seton Hall University Dissertations and Theses (ETDs)

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Abstracts Of Papers, 80th Annual Meeting Of The Virginia Academy Of Science, May 22-24, 2002, Hampton University, Hampton, Virginia

Virginia Journal of Science

Abstracts of papers that were presented at the 80th annual meeting of the Virginia Academy of Science.

Chemical And Toxicological Characterization Of Tidal Freshwater Areas In The James River, Virginia From Jamestown Island To Jordan Point, Morris H. Roberts Jr., Mary Ann Vogelbein, Mark A. Richards, Lou Seivard

Reports

No abstract provided.

Novel Synthesis Of 2-Methyl-3, 4, 5-Trichloropyrimidine, Daniel M. Goldman

Theses

A one-step synthesis of the heterocycle 2-methyl-3,4,5-trichloropyrimidine by the cycloaddition of hexachloropropene with acetamidine hydrochloride in methanolic NaOH was attempted. The product was dark amber oil. A by-product of this reaction was sodium chloride. The proposed reaction was expected to proceed via a SN2 nucleophilic displacement of three chlorine atoms on hexachloropropene by acetamidine, the nucleophile. The proposed driving force for this transformation is the lone pair of electrons on the amidine nitrogen along with the electron withdrawing ability of three chlorines on hexachloropropene which induces a partial positive charge on the carbon. It is proposed that the chlorine atoms …

Zr-Pendent Polyimide Carbon/Glass Composites And Their Property Comparisons With The Corresponding Non Pendent Polyimide Composites, Sangeeta Nangia

Theses

The objective of this research project is to synthesize two and three component polyimide by solution polymerization technique. Further, to synthesize four-component pendent polyimides by attaching the zirconium complex to the three component (3,4' -ODA/ODPA/MADA) polyimide backbones in presence of DCC to give the atomic oxygen resistant polyamic acid and polyimide. The synthesized zirconium complex pendent polyamic acid was characterized by Thin Layer Chromatography (TLC) to investigate its formation. TLC results indicated that no free zirconium complex remain in the polymer solution. Woven glass and carbon fibres were impregnated with the polyamic acid in the ratio of 40:60 of the …

The Splicing Of U12-Type Introns Is A Rate-Limiting Step In Gene Expression, Abhijit A. Patel

Yale Medicine Thesis Digital Library

Metazoan genes have recently been found to contain a novel class of introns that display non-canonical consensus sequences and are excised by a distinct splicing machinery. These introns occur very rarely, and have been called U12-type introns because recognition of their branch point sequences requires the U12 snRNP, which performs an analogous function to the U2 snRNP in splicing major-class introns. The persistence of two spliceosomes throughout virtually all of metazoan evolution suggests that the two spliceosomes play distinct and probably indispensable cellular roles. One enticing possibility is that the U12-type spliceosome functions in post-transcriptional regulation, serving as the rate-determining …

Footprinting And Circular Dichroism Studies On Paromomycin Binding To The Packaging Region Of Human Immunodeficiency Virus Type-1, Mark P. Mcpike, Jerry Goodisman, James C. Dabrowiak

Chemistry - All Scholarship

We have studied the interaction of the aminoglycoside drug, paromomycin, with a 171-mer from the packaging region of HIV-1 (ψ-RNA), using quantitative footprinting and circular dichroism spectroscopy. The footprinting autoradiographic data were obtained by cutting end-labeled RNA with RNase I or RNase T1 in the presence of varying paromomycin concentrations. Scanning the autoradiograms produced footprinting plots showing cleavage intensities for specific sites on the ψ-RNA as functions of drug concentration. Footprinting plots showing binding were analyzed using a two-state model to give apparent binding constants for specific sites of the ψ-RNA. These plots show that the highest-affinity paromomycin binding site …

Erv14p Directs A Transmembrane Secretory Protein Into Copii-Coated Transport Vesicles, Jacqueline Powers, Charles Barlowe

Dartmouth Scholarship

Erv14p is a conserved integral membrane protein that traffics in COPII-coated vesicles and localizes to the early secretory pathway in yeast. Deletion of ERV14 causes a defect in polarized growth because Axl2p, a transmembrane secretory protein, accumulates in the endoplasmic reticulum and is not delivered to its site of function on the cell surface. Herein, we show that Erv14p is required for selection of Axl2p into COPII vesicles and for efficient formation of these vesicles. Erv14p binds to subunits of the COPII coat and binding depends on conserved residues in a cytoplasmically exposed loop domain of Erv14p. When mutations are …

A Post-Amadori Inhibitor Pyridoxamine Also Inhibits Chemical Modification Of Proteins By Scavenging Carbonyl Intermediates Of Carbohydrate And Lipid Degradation, Paul A. Voziyan, Thomas O. Metz, John W. Baynes, Billy G. Hudson

Faculty Publications

Reactive carbonyl compounds are formed during autoxidation of carbohydrates and peroxidation of lipids. These compounds are intermediates in the formation of advanced glycation end products (AGE) and advanced lipoxidation end products (ALE) in tissue proteins during aging and in chronic disease. We studied the reaction of carbonyl compounds glyoxal (GO) and glycolaldehyde (GLA) with pyridoxamine (PM), a potent post-Amadori inhibitor of AGE formation in vitro and of development of renal and retinal pathology in diabetic animals. PM reacted rapidly with GO and GLA in neutral, aqueous buffer, forming a Schiff base intermediate that cyclized to a hemiaminal adduct by intramolecular …

Magnetoacoustic Chemical Sensors Based On Swellable Polymer Microspheres, Huqun Liu

Doctoral Dissertations

The goal of this dissertation was to investigate chemical applications of magnetoacoustic sensors based on swellable polymer microspheres. The magnetoacoustic sensor was used to monitor viscosity of starch solution, water loading, and 2-hydroxyethyl methacrylate polymerization.

Poly(vinylbenzyl chloride) (polyVBC) microspheres were prepared by suspension polymerization and then derivatized to introduce dicarboxylate groups onto the polymer backbone. Poly(vinylbenzyl chloride-trichlorophenyl acrylate) (polyVBC-TCPA) microspheres were prepared by dispersion polymerization and then derivatized to introduce amine groups onto the polymer backbone. These derivatized polymer microspheres swell and shrink with changing pH. They were entrapped in a hydrogel membrane and the membrane turbidity was investigated by …

Diels -Alder Reactions Of [60]Fullerene With 1,2,4,5-Tetrazines And Additions To [60]Fullerene-Tetrazine Monoadducts, Mark Christopher Tetreau

Doctoral Dissertations

The Diels-Alder reaction between [60]fullerene and 1,2,4,5-tetrazines was studied. Under conditions of total darkness, [60]fullerene reacts with tetrazines to form bicyclic intermediates which immediately extrudes nitrogen to yield C2nu symmetric monoadducts. Thus, 3,6-diphenyl and 3,6-di-(2 '-pyridyl)-1,2,4,5-tetrazines react with [60]fullerene to form the corresponding C2nu symmetric monoadduct. To successfully synthesize these [60]fullerene-tetrazine monoadducts, the Diels-Alder reactions must be run in total darkness. In the presence of light and acid catalyst, the monoadducts are susceptible to nucleophilic attack by water leading to novel hydration/rearrangement products that contain 4,5-dihydropyrazole groups nested atop the [60]fullerene skeleton.

The [60]-fullerene-tetrazine monoadducts also react with primary amines …

Ketomethylene Isosteric Amide Bond Replacements Via The Zinc -Mediated Chain Extension Of N -Protected Amino Acids, Cory Robert Theberge

Doctoral Dissertations

A methodology for the chain extension of N-protected amino acid beta-keto esters to gamma-keto esters utilizing a zinc carbenoid was developed. The reaction was used on amino acids containing various protective groups and a variety of side chain functionality. This method was used in the incorporation of ketomethylene isosteric amino acid replacements within amino acid sequences. The usefulness of the method on molecules supported by a solid phase was explored.

A Facile Conversion Of Beta-Keto Carbonyl Compounds To Alpha, Beta-Unsaturated-Gamma-Oxo Carbonyl Systems And A Study Of Ketal -Derived Oxonium Ylides, Matthew David Ronsheim

Doctoral Dissertations

An efficient method for the conversion of versatile beta-keto carbonyl compounds to the corresponding alpha,beta-unsaturated-gamma-oxo carbonyl structural units was developed. This methodology was applied to beta-keto esters, amides and lactones. In most cases generation of the olefinic functionality proceeded with complete E-selectivity. The utility of this chemistry was demonstrated through a formal synthesis of R-(-)-pyrenophorin, an asymmetric total synthesis of (+)-patulolide A and a racemic synthesis of patulolide B. An extensive study of ketal-derived oxonium ylides and the subsequent rearrangement was also accomplished. The application of this chemistry was applied to Bu-2313 and a unique class of compounds known as …

Thermodynamic Properties Of Mixed Lennard -Jones Atomic Clusters, Ronald P. White

Doctoral Dissertations

Using Monte Carlo simulation techniques, we have determined thermodynamic and structural properties of argon-xenon and argon-krypton mixed noble gas clusters modeled by the Lennard-Jones potential. The efficiency and reliability of the simulations were enhanced through the implementation of an advanced sampling technique, the parallel tempering method. Results have been obtained over a wide range of temperature for all binary mixed cluster species containing up to fourteen atoms.

A primary focus in this work was the calculation of cluster free energies and other entropic thermodynamic quantities. These were obtained from simulations by calculating the cluster partition function through strategies involving potential …

Improved Swellable Polymer Microspheres For Chemical Sensing, Necati Kaval

Doctoral Dissertations

Derivatized lightly crosslinked polymer microspheres that swell and shrink as a function of pH have been investigated to develop polymeric transduction elements for fiber optic sensors and other sensors. The microspheres were immobilized in hydrogels forming a membrane. The membranes look turbid because of the difference between the refractive index of hydrogel and the refractive index of microspheres. As the microspheres swell as a function of pH, their refractive index decreases approaching the refractive index of the hydrogel. As a result, the turbidity of the membrane decreases. The change in the turbidity of the membrane was monitored by a UV-Vis-NIR …

Simultaneous Determination Of Nitrous Oxide And Ammonia For Measurement Of In-Situ Fluxes From Natural Ecosystems By Gas Chromatography With Headspace Autosampler And Electron Capture Detection, Richard Joseph Puk

Doctoral Dissertations

Anthropogenic disturbance of the soil nitrogen cycle by changes in nitrogen and carbon availability influences the production of N2O and NH 3 emissions to the atmosphere affecting the environment and human health. This dissertation presents a new method for automated gas chromatographic analysis of N2O and NH3 and quantifies fluxes from a salt marsh and tropical rain forest.

The automated system used single column gas chromatograhic separation on HayeSep Q and electron capture detection. Air (N2+O 2), N2O and NH3 are separated with retention times of 0.9, 1.7 and 2.15 minutes respectively. Samples were stored in headspace autosampler vials until …

Mechanism Of Activation Of Photoreceptor Phosphodiesterase By Transducin And By Low Molecular Weight Proteins, Angela W. Norton

Doctoral Dissertations

Rod photoreceptor phosphodiesterase (PDE) is the central enzyme of visual transduction. PDE is a heterodimer (Palphabeta) with two associated inhibitory gamma subunits, and is bound to the disk membrane by isoprenyl groups. Each catalytic subunit contains a catalytic site and a high-affinity cGMP binding site. In this research, two independent mechanisms of PDE regulation are addressed. The first part examines transducin activation of PDE, focusing on the interactions between the gamma subunits and Palphabeta. The second part examines the 17 kDa delta protein believed to regulate bovine PDE. We found that transducin activation of PDE induces heterogeneity at the active …

Chemistry Discipline Capstone Course Assessment 2001/2002, Chemistry Discipline

Assessment of Student Learning Reports

No abstract provided.

Chemistry Discipline Assessment Report 2001/2002, Chemistry Discipline

Assessment of Student Learning Reports

No abstract provided.

Synthesis And Electronic, Magnetic Properties Of Low-Dimensional Organometallic Reduced Mesoporous Niobium Oxide Composites., Xun. He

Electronic Theses and Dissertations

Herein I report the synthesis of a new family of organometallic reduced mesoporous niobium oxide composites with mixed oxidation-state organometallic nanowires in the pores and investigate their electronic and magnetic properties. This is a wonderful system which allows us to systematically study one-dimensional molecular metals based on the respective organometallic species and the reducible mesoporous niobium oxide structure. Investigations were conducted on the effects of electron configuration, ionization potential, and electron affinity of organometallic species as well as the composition of mesoporous transition metal oxide walls on the electronic and magnetic properties in the composites and the loading level of …

Synthesis And Reactivity Of Group 4, 5, 13, And 14 Phosphinimide Complexes., Silke. Courtenay

Electronic Theses and Dissertations

A variety of complexes bearing the phosphinimide ligand, ranging from transition metal to main-group compounds, have been investigated. Reduction of CpTi(NPt-Bu3)Cl2 by magnesium powder resulted in the formation of the dimeric Ti(III)-species (CpTi(NPt-Bu3)(mu-Cl))2 2.1 , which was investigated by a single crystal EPR study. Reduction of CpTi(NPt-Bu3)Cl2 in the presence of 2,3-dimethyl-1,3-butadiene resulted in the formation of the butadiene complex CpTi(NPt-Bu3)(eta2-CH2C(CH3)C(CH 3)CH2) 2.2. The synthesis and reactivity of a variety of Cp*Ta-phosphinimide complexes have been explored. Reaction of stoichiometric amounts of R3PNTMS with Cp*TaCl4 afforded the complexes Cp*Ta(NPR3)Cl 3 (R = t-Bu3 3.1, i-Pr3 3.2). Further derivatization of 3.1 and …

Climate/Chemistry Effects Of The Pinatubo Volcanic Eruption Simulated By The Uiuc Stratosphere/Troposphere Gcm With Interactive Photochemistry, E. V. Rozanov, M. E. Schlesinger, N. G. Andronova, F. Yang, S. L. Malyshev, V. A. Zubov, T. A. Egorova, B. Li

Faculty Publications

The influence of the sulfate aerosol formed following the massive Pinatubo volcanic eruption in June 1991 on the chemical composition, temperature, and dynamics of the atmosphere has been investigated with the University of Illinois at Urbana-Champaign (UIUC) stratosphere-troposphere General Circulation Model (GCM) with interactive photochemistry (ST-GCM/PC). Ensembles of five runs have been performed for the unperturbed (control) and perturbed (experiment) conditions. The simulated repartitioning within the chlorine and nitrogen groups, as well as the ozone changes, are in reasonable quantitative agreement with observations and theoretical expectations. The simulated ozone changes in the tropics reveal the ozone mixing ratio decreases below …

Characterization Of The Effects Of Biosynthetically Incorporated Tryptophan Analogues In Rat Parvalbumin F102w And Structure-Function Studies Of Tryptophanyl-Trna Synthetase., Mauro. Acchione

Electronic Theses and Dissertations

Fluorescence spectroscopy of tryptophan residues is a valuable tool for dissecting the structure, function and dynamic behaviour of proteins. An important step in method development is the use of tryptophan analogues with unique photophysical properties that extend the utility of intrinsic protein fluorescence. Two difficulties limit the use of these analogues. Their structure, while similar to that of tryptophan, can perturb native protein structure resulting in misfolding or inactivity. There are also problems from an inability of tryptophanyl-tRNA synthetase (TrpRS) to use these analogues as a substrate in the tRNA charging reaction. The tryptophan residue in rat parvalbumin F102W is …

Engineering, Overexpression, Purification And Analytical Applications Of Recombinant Bioluminescent Reporters., Monique Elise. Verhaegen

Electronic Theses and Dissertations

The initial project entailed the construction of a plasmid suitable for bacterial expression of the in vivo biotinylated aequorin photoprotein. The plasmid contained a biotin-acceptor coding sequence fused in-frame with the apoaequorin gene as well as the birA gene, encoding biotin protein ligase (BPL), responsible for post-translational biotinylation. The use of the biotin tag facilitated (a) the purification of aequorin from the crude cell extract using an avidin resin and (b) the direct complexation of aequorin with streptavidin for utilization as a reporter molecule. Streptavidin-biotinylated aequorin complexes were used for the quantification of biotinylated hybrids in a hybridization assay, with …

Infrared, Raman And Surface-Enhanced Resonance Raman Scattering Of N-Butylimido, Ethyleneamine Perylene (Ptcd-Nh(2)): Single-Molecule Detection Using Colloidal Silver And Silver Island Films., Tibebe. Lemma Mukria

Electronic Theses and Dissertations

The vibrational spectra and the surface-enhanced (resonance) Raman scattering (SERS/SERRS) of a perylene dye containing a terminal NH2 group, n-butylimido, ethyleneamine perylene (PTCD-NH2) have been studied. The infrared, Raman and resonance Raman spectra of the material were recorded and vibrational fundamentals assigned. The vibrational assignments of fundamentals were aided with an ab-initio Hartree-Folk at 6-31G level of theory. Langmuir-Blodgett monolayers of the neat material were fabricated and the pi-A isotherms recorded. Mixed monolayers were also studied for applications in SERBS. The spectra of evaporated thin solid films were obtained and a complete spectroscopic characterization of these films is presented in …

Scholarly Communication: The Use And Non-Use Of E-Print Archives For The Dissemination Of Scientific Information, Ibironke Lawal

VCU Libraries Faculty and Staff Publications

This study surveyed a randomly chosen sample from a population of 240,000 scholars in nine scientific disciplines from private and public colleges and universities across the United States and Canada. The disciplines included physics/astronomy, chemistry, mathematics/computer science, engineering, cognitive science/psychology, and biological sciences. The survey sought to determine use and non-use of e-print archives in the different disciplines. Results show that 18 percent of the researchers use at least one archive while 82 percent do not use any. Scholars in physics use e-print archives the most and chemistry the least. ArXiv receives the most use and authors' web sites the …