Physical Sciences and Mathematics Commons^™

Electrochemical Reduction Characteristics Of Nitrobenzene At The Copper Electrode, Jin-Hong Fan, Wen-Ying Xu, Ting-Yao Gao

Journal of Electrochemistry

The electrochemical reduction characteristics and transition steps of nitrobenzene aqueous solution at the copper electrode, as well as its reduction mechanism were extensively investigatedby using the techniques such as cyclic voltammetry(CV) and linear scan voltammetry(LSV). The results showed that the reduction peaks of nitrobenzene at the copper electrode were located at 0.58 V and 1.32 V or so (vs. SCE), both acidity and alkalinesolutionsfavoredthe reduction of nitrobenzene. The adsorption of compounds followed by the reduction process, which is controlled by the mass transfer step at higher nitrobenzene concentration. In addition, the higher anaerobic degree led to faster reduction rate.

Electrochemical Behavior And Determination Of Curcumin, Ping Wu, Wei Chen, Ya-Feng Zhang, Xin-Hua Lin

Journal of Electrochemistry

In 0.1mol/L phosphate buffer solution (pH 3.0), the voltammetry behaviors of curcumin at a glassy carbon electrode have been studied.One pair of current peaks of the voltammogram may be attributed to a reversible one-electron transfer of curcumin molecules at the glassy carbon electrode.A new method, the differential pulse voltammetry,for curcumin determination is described. The adsorptive potential of curcumin is (+0.8) V(vs. SCE),while its peak potential of curcumin is +0.386V(vs. SCE).The peak current is proportional to the concentration of curcumin over the rage of 1.0×10~(-8)mol/L ~2.5×10~(-7)mol/L.A detection limit of 4.0×10~(-9)mol/Lof curcumin can be estimated. The method is simple, rapid, sensitive and …

5~(Th)Asian Conference On Electrochemistry, Acec2005 Held In Shanghai

Journal of Electrochemistry

No abstract provided.

Post-Translational Regulation Of Adipose Differentiation-Related Protein By The Ubiquitin/Proteasome Pathway, John Tansey

Chemistry Faculty Scholarship

Adipose differentiation-related protein (ADRP) is localized to lipid droplets in most mammalian cells. ADRP, proposed to regulate
fatty acid mobilization and lipid droplet formation, is linked to lipid accumulation in foam cells of human atherosclerotic
lesions. In this report, we show that ADRP protein accumulates in Chinese hamster ovary fibroblastic cells cultured in the
presence of oleic acid but is destabilized when fatty acid sources are removed from culture serum. The latter effect was blocked
by the proteasome inhibitor MG132, whereas inhibitors of other proteolytic processes were ineffective. Pulse-chase experiments
confirmed that ADRP degradation is inhibited by MG132. Conditions that …

Unraveling The Mechanism Of A Potent Transcriptional Activator, Brian Brennan, Zhen Lu, Steven Rowe, Sarah Davis, Renee Metzler, Johnathan Nau, Chinmay Majmudar, Anna Mapp, Aseem Ansari

Brian B. Brennan

Despite their enormous potential as novel research tools and therapeutic agents, artificial transcription factors (ATFs) that up-regulate transcription robustly in vivo remain elusive. In investigating an ATF that does function exceptionally well in vivo, we uncovered an unexpected relationship between transcription function and a binding interaction between the activation domain and an adjacent region of the DNA binding domain. Disruption of this interaction leads to complete loss of function in vivo, even though the activation domain is still able to bind to its target in the transcriptional machinery. We propose that this interaction parallels those between natural activation domains and …

Pm Emission From A Commercial Jet Engine -- Project Apex, Donald E. Hagen, Philip D. Whitefield, Prem Lobo, Max B. Trueblood

Physics Faculty Research & Creative Works

Project APEX (Aircraft Particle Emissions eXperiment) was a multi-agency commercial aircraft emission characterization and technology demonstration experiment. Its objective was to characterize particle and trace gas precursor species in the emissions from a NASA DC-8 aircraft with General Electric CFM56-2C1 engines at the engine exit plane as well as selected down stream locations. This was to advance the understanding of particle emissions and their evolution in the atmosphere from a current in-service turbofan engine. The test was conducted at the NASA Dryden Flight Research Center at Edwards Air Force Base California during April 15-30, 2004. Participants included the National Aeronautics …

Cell Toxicity And Uptake Of Rrr-Alpha-Tocopheryl Polyethylene Glycol 1000 Succinate (Tpgs) By Various Cell Ines In Vitro., Christelle Komguem Kamga

Electronic Theses and Dissertations

This research focused on investigating and comparing the cytotoxicity and cellular uptake of RRR-alpha-tocopheryl polyethylene glycol succinate (TPGS, with that of alpha-tocopheryl succinate (α-TS). Both TPGS and α-TS are water-soluble forms of vitamin E with important clinical applications. Cytotoxicity assays with RAW 264.7 and LNCaP cells incubated overnight with TPGS or α-TS at concentrations ≥ 12.4 μM suggest that α-TS is more cytotoxic than TPGS. Macrophages were found to be more sensitive than LNCaP cells when treated with similar concentrations of α-TS. For both cell lines, most of the TPGS or α-TS taken up remained esterified after 24 hours. Our …

Potential Energy Surface Around The Tropylium Ion., Kenneth Wayne Bullins

Electronic Theses and Dissertations

The formation of the tropylium ion, C₇H₇⁺, in the mass spectrum of toluene is a chemical process that has been studied extensively in the past. The advances in computational power of personal computers have made the investigation of the pathway to form this ion and its subsequent decomposition feasible at a fairly high level of theory. The calculations that we performed were at the HF/6-31G (d, p) and the B3LYP/6-311++G (2d) levels. This work will show areas of the potential energy surface around the highly symmetric tropylium ion to give a glance of possible mechanisms …

Cell Toxicology Study Of Rrr-Alpha-Tocopheryl Polyethylene Glycol 1000 Succinate (Tpgs)., Clarisse Sornsay Muenyi

Electronic Theses and Dissertations

This research focused on the cytotoxic properties of RRR-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS) in transformed and cancerous cell lines. We used RAW264.7 macrophage and prostate cancer (LNCaP) cell lines in this study. TPGS caused cell death and decreased cell viability in a dose and time dependent manner. Cell death was evaluated fluorimetrically by employing the nucleic acid-binding fluorophore; propidium iodide. A colorimetric 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay was used to evaluate cell viability. Cell death can occur through necrosis or apoptosis. Our results suggested that TPGS triggered apoptotic cell death. Induction of apoptosis, as measured by caspase …

Electrochemical Remedy And Analysis For The Environment Based On The New Polymer-Dna Composite Material., Noor Feuza Hussain

Electronic Theses and Dissertations

In this work a new material, the conducting polymer-DNA composite, has been reported for the first time due to its promise in micro extraction, transfer, and release of cations under controlled potential conditions by using electrochemically assisted solid phase micro extraction (SPME). The Polypyrrole/DNA composite can be formed easily by oxidation of pyrrole monomers in the presence of chromosomal DNA by electropolymerization. Environmental significant pollutants such as Cd, Pb, Hg, Co, Zn, Cu, and Bi metal ions can be extracted from the aqueous solution and are able to be transferred to another medium defined as the release solution where the …

Multiscale Modeling, Simulations, And Experiments Of Coating Growth On Nanofibers. Part Ii. Deposition, A. Buldum, C. B. Clemons, L. H. Dill, K. L. Kreider, G. W. Young, X. Zheng, Edward A. Evans, G. Zhang, S. I. Hariharan

Chemical, Biomolecular, and Corrosion Engineering Faculty Research

This work is Part II of an integrated experimental/modeling investigation of a procedure to coat nanofibers and core-clad nanostructures with thin-film materials using plasma-enhanced physical vapor deposition. In the experimental effort, electrospun polymer nanofibers are coated with aluminum materials under different operating conditions to observe changes in the coating morphology. This procedure begins with the sputtering of the coating material from a target. Part I [J. Appl. Phys. 98, 044303 (2005)] focused on the sputtering aspect and transport of the sputtered material through the reactor. That reactor level model determines the concentration field of the coating material. This field serves …

Multiscale Modeling, Simulations, And Experiments Of Coating Growth On Nanofibers. Part I. Sputtering, A. Buldum, I. Busuladzic, C. B. Clemons, L. H, Dill, K. L. Kreider, G. W. Young, Edward A. Evans, G. Zhang, S. I. Hariharan, W. Kiefer

Chemical, Biomolecular, and Corrosion Engineering Faculty Research

This paper is Part I of an integrated experimental/modeling investigation of a procedure to coat nanofibers and core-clad nanostructures with thin-film materials using plasma-enhanced physical vapor deposition. In the experimental effort, electrospun polymer nanofibers are coated with aluminum under varying operating conditions to observe changes in the coating morphology. This procedure begins with the sputtering of the coating material from a target. This paper focuses on the sputtering process and transport of the sputtered material through the reactor. The interrelationships among the processing factors for the sputtering and transport are investigated from a detailed modeling approach that describes the salient …

Low-Temperature Activation Conditions For Pamam Dendrimer Templated Pt Nanoparticles, Anil Singh, Bert D. Chandler

Chemistry Faculty Research

Surface immobilized polyamidoamine (PAMAM) dendrimer templated Pt nanoparticles were employed as precursors to heterogeneous catalysts. CO oxidation catalysis and in situ infrared spectroscopy were used to evaluate conditions for dendrimer removal. Infrared spectroscopy showed thatPAMAMdendrimer amide bonds begin decomposing at temperatures as low as 75 °C. Although the amide stretches are completely removed after 3 h of oxidation at 300 °C, 16 h were required to reach maximum catalytic activity. Further treatment under oxidizing or reducing atmospheres did not cause substantial changes in activity. Infrared spectroscopy of the activated materials indicated that organic residues, probably surface carboxylates, are formed during …

A Nested-Pcr With An Internal Amplification Control For The Detection And Differentiation Of Bartonella Henselae And B. Clarridgeiae: An Examination Of Cats In Trinidad, Joanne Rampersad, John D. Watkins, Michael S. Samlal, Raymond Deonanan, Shalini Ramsubeik, David Ammons

Chemistry Faculty Publications and Presentations

Background

Bartonella species are bacterial blood parasites of animals capable of causing disease in both animals and man. Cat-Scratch Disease (CSD) in humans is caused mainly by Bartonella henselae and is acquired from the cat, which serves as a reservoir for the bacteria. A second species, B. clarridgeiae is also implicated in the disease. Diagnosis of Bartonellosis by culture requires a week or more of incubation on enriched media containing blood, and recovery is often complicated by faster growing contaminating bacteria and fungi. PCR has been explored as an alternative to culture for both the detection and species identification of …

Tris(1,10-Phenanthroline)Cobalt(Ii) Triiodide, Meredith A. Tershany, Andrea M. Goforth, Mark D. Smith, Leroy Peterson Jr., Hans-Conrad Zur Loye

Faculty Publications

The asymmetric unit of the title compound, [Co(C₁₂H₈N₂)₃](I₃)₂, contains one [Co(1,10-phenanthroline)₃]²⁺ cation, half each of two centrosymmetric triiodide anions, and one complete triiodide anion. The title compound was synthesized solvothermally from Co(NO₃)₂, 1,10-phenanthroline, and SnI₂, where the SnI₂ reagent serves only as a source of I atoms.

Computational And Esr Studies Of Electron Attachment To Decafluorocyclopentane, Octafluorocyclobutane, And Hexafluorocyclopropane: Electron Affinities Of The Molecules And The Structures Of Their Stable Negative Ions As Determined From ¹³C And 19f Hyperfine Coupling Constants, Adel M. Elsohly, Gregory S. Tschumper, Richard A. Crocombe, Jih Tzong Wang, Ffrancon Williams

Chemistry Faculty Research & Creative Works

High-resolution ESR spectra of the ground-state negative ions of hexafluoro cyclopropane (c-C3F6.-), octafluorocyclobutane (c-C4F8.-), and decafluorocyclopentane (c-C5F10.-) are reported and their isotropic 19F hyperfine coupling constants (hfcc) of 198.6 ± 0.4 G, 147.6 ± 0.4 G, and 117.9 ± 0.4 G, respectively, are in inverse ratio to the total number of fluorine atoms per anion. Together with the small value of 5.2 ± 0.4 G determined for the isotropic 13C hfcc of c-C4F8.-, these results indicate that in each case the singly occupied molecular orbital (SOMO) is delocalized over the equivalent fluorine's and possesses a nodal plane through the carbon …

Lanthanide Separation Using Rate-Controlled Solvent Extraction, Joey Edwin Dickson

Doctoral Dissertations

Solvent extractions of many of the lanthanide ions in both single ion and mixed ion environments have been carried out. These cations were first complexed with an aqueous complexing agent and were extracted with DEHPA (di-2 ethylhexylphosphoric acid) in an organic phase (kerosene). The experiments were designed to measure the rates of extraction in the hope that separation factors might be enhanced under non-equilibrium conditions. The complexing agents tried include ethylenediaminetetraacetic acid (EDTA), tetraethylenepentamine (tetraen), nitrilotriacetic acid (NTA), and diethylenetriamine (dien). These represent a hexadentate, pentadentate, tetradentate, and tridentate agent respectively. EDTA was determined to give the best results for …

Synthesis And Applications Of Monolithic Hplc Columns, Chengdu Liang

Doctoral Dissertations

Silica and carbon monolithic columns were synthesized and modified for liquid chromatography applications. Column configurations and cladding techniques were investigated in detail. Three novel approaches have been developed for the synthesis of bimodal porous rods. Out of these three methods, gel-casting was adopted for the synthesis of silica monoliths with ordered mesopores and uniform macropores; the use of colloidal templates and dual phase separation has been successfully implemented for the synthesis of carbon monoliths with well-controlled meso- and macro- porosities. The formation of mesopores in carbon materials has been further studied in the microphase separation of block copolymers. Electrochemical modification …

Tungsten Alkyl Alkylidyne And Bis(Alkylidene) Complexes. Their Unusual Inter-Conversion And Reactions With Phosphines, Dioxygen And Water, Laurel Anne Morton

Doctoral Dissertations

This dissertation focuses on the unique chemistry of d0 alkylidyne and bis (alkylidene) complexes with β-silicon atoms. The goals of this dissertation research were to prepare and characterize these new d0 transition metal complexes, to study their reactivities including thermodynamics and kinetics of the inter-conversion between the alkylidyne and bis(alkylidene) complexes, and to explore the mechanism of the reactions of O2 or water with d0 alkylidyne complexes.

A summary of the research in this dissertation is provided in Chapter 1.Chapter 2 reports the study of an unusual exchange between new alkyl alkylidyne and bis(alkylidene) complexes …

Synthesis Of A C-Linked Methyl Β-Disaccharide As A Building Block Of Hyaluronic Acid Oligosaccharide Mimetics, Kpakpo Ambroise Akue

Doctoral Dissertations

Hyaluronic acid is a viscous high MW polysaccharide that is synthesized in the plasma membrane. It is found in the connective tissue space, in the synovial fluid of movable joints and in the vitreous humor of the eye. Its chemical structure is composed of a repeating disaccharide unit in which D-glucuronic acid is linked to the 3-position of N-acetyl-D-glucosamine. It appears to play an important role in the metastasis of cancer cells since cancer cell’s CD44 receptors adhere to it and migrate to host cells. Our goal was to synthesize small HA-oligosaccharides that would behave as CD44 metastasis receptor antagonists. …

Understanding And Controlling The Molecular Level Processes Involved In The Development Of Latent Fingerprints Using The Cyanoacrylate Fuming Method, Stephen Paul Wargacki

Doctoral Dissertations

The cyanoacrylate fuming method (CFM) is the standard method for forensic investigators to develop latent fingerprints from nonporous substrates. Variations in the effectiveness of the technique and the quality of the ethylcyanoacrylate (ECA) polymer impression formed during the development process have lead researchers to investigate the fundamental reactions between the print residue and the developing vapor. Identification of the active initiating species in the residue is an essential first step to understanding the development process. The fingerprint residue is composed primarily of water and eccrine salts, of which, water is generally accepted as the active initiator. However, initiation by water …

The Clearance Of Protein-Bound Solutes By Hemofiltration And Hemodiafiltration, Timothy W. Meyer, Jason L. Walther, Maria Enrica Pagtalunan, Andres W. Martinez, Ali Torkamani, Patrick D. Fong, Natalie S. Recht, Channing R. Robertson, Thomas H. Hostetter

Chemistry and Biochemistry

Background. Hemofiltration in the form of continuous venovenous hemofiltration (CVVH) is increasingly used to treat acute renal failure. Compared to hemodialysis, hemofiltration provides high clearances for large solutes but its effect on protein-bound solutes has been largely ignored.

Methods. Standard clinical systems were used to remove test solutes from a reservoir containing artificial plasma. Clearances of the protein-bound solutes phenol red (C_PR) and indican (C_IN) were compared to clearances of urea (C_UREA) during hemofiltration and hemodiafiltration. A mathematical model was developed to predict clearances from values for plasma flow Q_p, …

Synthesis And Characterization Of Highly Amine Functionalized Mesoporous Organosilicas By An “All-In-One” Approach, Rebecca Voss, Arne Thomas, Markus Antonietti, Geoffrey A. Ozin

Rebecca Cademartiri

Mesoporous organosilicas (MOs) represent a promising class of organic–inorganic nanocomposites for a broad range of applications like catalysis, sensing, separation, or microelectronics. Their distinct feature is the presence of organic groups incorporated into the channel walls of a mesoporous structure. Here, we present a convenient “all-in-one” approach using silsesquioxane surfactant precursors for the functionalization of the channel walls with primary amine groups. The monomer is made by a hydroboration/aminolysis sequence on the base of a commercial monomer, with the template bound to the functionalization site by hydroboration and released after silica condensation and aminolysis. This combination ensures both the placement …

Impact Of Palmitic Acid Coating On The Water Uptake And Loss Of Ammonium Sulfate Particles, R. M. Garland, M. E. Wise, M. R. Beaver, H. L. Dewitt, A. C. Aiken, J. L. Jimenez, M. A. Tolbert

CUP Faculty Research

While water insoluble organics are prevalent in the atmosphere, it is not clear how the presence of such species alters the chemical and physical properties of atmospheric aerosols. Here we use a combination of FTIR spectroscopy, Transmission Electron Microscopy (TEM) and Aerosol Mass Spectrometry (AMS) to characterize ammonium sulfate particles coated with palmitic acid. Coated aerosols were generated by atomizing pure ammonium sulfate, mixing the particles with a heated flow of nitrogen with palmitic acid vapor, and then flowing the mixture through an in-line oven to create internally mixed particles. The mixing state of the particles was probed using the …

Measurements Of Secondary Organic Aerosol From Oxidation Of Cycloalkenes, Terpenes, And M-Xylene Using An Aerodyne Aerosol Mass Spectrometer, Roya Bahreini, Melita D. Keywood, Nga L. Ng, Varuntida Varutbangkul, Song Gao, Richard C. Flagan, John H. Seinfeld, D. R. Worsnop, J. L. Jimenez

Chemistry and Physics Faculty Articles

The Aerodyne aerosol mass spectrometer (AMS) was used to characterize physical and chemical properties of secondary organic aerosol (SOA) formed during ozonolysis of cycloalkenes and biogenic hydrocarbons and photooxidation of m-xylene. Comparison of mass and volume distributions from the AMS and differential mobility analyzers yielded estimates of “effective” density of the SOA in the range of 0.64−1.45 g/cm³, depending on the particular system. Increased contribution of the fragment at m/z 44, CO₂⁺ ion fragment of oxygenated organics, and higher “Δ” values, based on ion series analysis of the mass spectra, in nucleation experiments …

Chlorella Virus-Encoded Deoxyuridine Triphosphatases Exhibit Different Temperature Optima, Yuanzheng Zhang, Hideaki Moriyama, Kohei Homma, James L. Van Etten

Hideaki Moriyama Publications

A putative deoxyuridine triphosphatase (dUTPase) gene from chlorella virus PBCV-1 was cloned, and the recombinant protein was expressed in Escherichia coli. The recombinant protein has dUTPase activity and requires Mg²⁺ for optimal activity, while it retains some activity in the presence of other divalent cations. Kinetic studies of the enzyme revealed a K_m of 11.7 μ M, a turnover k_cat of 6.8 s^-1, and a catalytic efficiency of k_cat/K_m = 5.8 x 10⁵ M^-1 s^-1. dUTPase genes were cloned and expressed from two other chlorella viruses …

Factors Affecting The Phase Separation Of Liquid Crystals From Acrylate-Based Polymer Matrices, Nathan Joseph Crawford

Doctoral Dissertations

The work presented in this dissertation covers the study of phase separation of small-molecule liquid crystals (LC's) from acrylate-based polymer matrices. These materials are used in the construction of polymer dispersed liquid crystals, or PDLC's, an emerging technology with applications ranging from privacy windows to photonic materials.

The first part of this study involves the determination of the effect of increasing polymer molecular weight on the solubility of the LC 4' -octyl-4-biphenyl carbonitrile, or 8CB, in poly(methyl methacrylate), or PMMA. Optical microscopy is used to determine the equilibrium phase diagrams for blends of 8CB and PMMA with weight-average polymer molecular …

Studies Directed Toward The Synthesis Of Acylated Phloroglucinols, Joseph Allen Burlison

Doctoral Dissertations

The synthesis and application of α-allenyl ketones directed toward the synthesis of polycyclic polyprenylated acylphloroglucinols are described. A functionalized α-allenyl ketone was synthesized in twelve steps starting from 2-methyl-2-cyclohexenome in 24% overall yield. The α’ stereocenter in the α-allenyl ketone was stereoselectively quaternized using a Tsuji allylation, Mukaiyama adol condensation sequence to afford C-1 functionalized allenyl cyclohexanone building blocks. A survey of acetals and reaction conditions for the Mukaiyama reaction suggested that 3-tert-butyldiphenylsiloxypropanal dimethyl acetal could be used, and indeed this reagent in the presence of TiCl₄∙Ti[OCH(CH₃)₂]₄ gave the aldol product …

(2+1) Resonance Enhanced Ionization Spectroscopy Of A State Selected Beam Of Oh Radicals, Margaret E. Greenslade, Marsha I. Lester, Dragana C. Radenovic, Andre J.A. Van Roij, David H. Parker

Chemistry

A state-selected beam of hydroxyl radicals is generated using a pulsed discharge source and hexapole field. The OH radicals are characterized by resonance-enhanced multiphoton ionization (REMPI) spectroscopy via the nested D  and 3  Rydberg states. Simplified spectra are observed from the selected ∣M_J∣ = 3/2 component of the upper Λ-doublet level of the lowest rotational state (J = 3/2) in ground (v″ = 0) and excited(v″ = 1–3) vibrational levels of the OH X  state. Two-photon transitions are observed to the D (v′ = 0–3) and 3 (v′ …

Fluorescent Photoinduced Electron Transfer (Pet) Cation Sensors Derived From Natural Products, Kenny Loo

Theses, Dissertations and Culminating Projects

Two new second generation fluorescent switches that are based on the chromophore-spacer-receptor architecture are reported in this thesis. The fluorescence modulation of these switches is a result of quenching or initiating photoinduced electron transfer (PET) between the chromophore and the receptors due to cation binding. These two molecules utilize an alkaloid, anabasine, as the proton receptor, and function as fluorescent off-on-off switches with decreasing pH. One of these molecules also utilizes a coumarin as the chromophore, making it the first rationally designed fluorescent PET system based on natural products. Further studies of two well-known first generation fluorescent switches to achieve …