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Trace Gas Emissions From Laboratory Biomass Fires Measured By Open-Path Fourier Transform Infrared Spectroscopy: Fires In Grass And Surface Fuels, Jon G. Goode, Robert J. Yokelson, Ronald A. Susott, Darold E. Ward

Chemistry and Biochemistry Faculty Publications

The trace gas emissions from six biomass fires, including three grass fires, were measured using a Fourier transform infrared (FTIR) spectrometer coupled to an open-path, multipass cell (OP-FTIR). The quantified emissions consisted of carbon dioxide, nitric oxide, water vapor, carbon monoxide, methane, ammonia, ethylene, acetylene, isobutene, methanol, acetic acid, formic acid, formaldehyde, and hydroxyacetaldehyde. By including grass fires in this study we have now measured smoke composition from fires in each major vegetation class. The emission ratios of the oxygenated compounds, formaldehyde, methanol, and acetic acid, were 1–2% of CO in the grass fires, similar to our other laboratory and …

Micromagnetics Simulation Of Nanoshaped Iron Elements: Comparison With Experiment, Ngocnga Dao, S. R. Homer, Scott L. Whittenburg

Chemistry and Biochemistry Faculty Publications

A micromagnetics simulation has been conducted on nanostructured magnetic elements of iron in order to investigate the effect of the shape of the element on magnetic properties, such as domain formation and hysteresis loops. These results are compared with recent experimental studies. The results display an impressive agreement with both the experimentally observed magnetic domains in individual particles as well as the shape of the hysteresis loops. The simulation results then explain features in the hysteresis loops in terms of vortice formation and motion.

Comparative Molecular Field Analysis (Comfa) Of Phenyl Ring Substituted Methylphenidates, Milind Misra

Theses

Comparative Molecular Field Analysis (CoMFA) was performed on 30 methylphenidate analogues having phenyl ring substituents at the 2-, 3-, and 4-positions in an attempt to explain the structure-activity relationships of the analogues. Several CoMFA studies were carried out using different conformations of methylphenidate as the template structures for the corresponding alignment rules. The identification of the bioactive conformation was variously based on the interfeature distances in WIN 35,428, on cluster analysis, and on a comparison of active methylphenidate analogues. The sensitivity of the models to various CoMFA parameters was compared. These parameters included altering the size and spacing of the …

A New Method For Preparing Self-Assembled Lipid Bilayers On Pt Electrode, Peng Diao, Dian-Lu Jiang, Xiao-Li Cui, Deng-Ping Gu, Ru-Ting Tong

Journal of Electrochemistry

A new method for preparing Pt-supported bilayer lipid membrane (Pt-BLM) on Pt electrode cleaned by high power ultrasound was reported. The reported method was convenient, costing less platinum and could be used to form large-area Pt-BLM as compared with the traditional Pt-wire-cutting method. The electrical properties of Pt-BLM were studied using electrochemical impedance spectroscopy and cyclic voltammetry. Experimental results showed that the values of membrane capacitance and the voltammetric characteristics were consistent with those of Pt-BLM prepared by traditional method.

Direct Electrolysis Of Seawater On Conducting Film For Microbial Anticorrosion 1. Simulation And Measurement Technique, Wei-Ling Hu, Ling-Ling Wu, Jing Zhou, Jing-Xin Li, Jin Luo, Zhong-Hua Lin

Journal of Electrochemistry

Based on the electrochemical micro probe and the weak signal detection technique, simulated test and measurement system were set up by the use of four-electrode cell(including a micro electrode), bipotentiostat, lock-in amplifier and three-dimensional micro manipulating device. Based on the system, the micrometer scale concentration distribution of trace hypochlorite, which is produced by direct electrolysis of seawater on the conducting film for preventing microbial corrosion has been obtained for the first time. Both relationships between concentration of hypochlorite and its reduction current, which is termed an working curve, and between the reduction current of hypochlorite and measured time are reported.

Spectroellipsometric Studies On Electrochemistry And Its Application, Zong-Qing Huang, Sheng-Tao Zhang, Shang-Fen Xie, Chang-Guo Chen, Yu-Ru Yang, Wei Zhu

Journal of Electrochemistry

Ellipsometric measurements are often extremely sensitive to the presence of very thin surface layers,to changes in their thickness (or coverage), and to changes in surface topography at an atomic scale. These characteristics make the use of ellipsometry for electrochemical studies particularly attractive. The ellipsometric studies on electrochemistry and its applications carried out in the Electrochemical Laboratory of Chongqing University are reviewed briefly: 1)The studies on electrochemistry of classical ellipsometry. 2)The new function V_op suggested by the authors. 3)The applications of new approcaches with new function V_op suggested by the authors.

Assignment Of The Infrared Spectra Of The Methanol Trimer, Gregory S. Tschumper, Jason M. Gonzales, Henry F. Schaefer

Chemistry Faculty Research & Creative Works

Second-order Möller-Plesset perturbation theory (MP2) and density functional theory (DFT) were employed to optimize two cyclic conformations of the methanol trimer, denoted "bowl" and "chair," as well as a third noncyclic, "open-chain" conformation. This is the first time all three methanol trimer conformations have been studied at the same level of theory. Harmonic vibrational frequencies confirm that all stationary points are minima on the intermolecular potential energy hypersurface. The chair is consistently predicted to be the most stable conformer. The bowl and open-chain conformers are only slightly less stable and lie within 3 kcal/mol. Results indicate that the bowl structure …

1H Nmr Studies On The Cua Center Of Nitrous Oxide Reductase From Pseudomonas Stutzeri, Richard C. Holz, Marcela L. Alvarez, Walter G. Zumft, David M. Dooley

Chemistry Faculty Research and Publications

¹H NMR spectra of the Cu_A center of N₂OR from Pseudomonas stutzeri, and a mutant enzyme that contains only Cu_A, were recorded in both H₂O- and D₂O-buffered solution at pH 7.5. Several sharp, well-resolved hyperfine-shifted ¹H NMR signals were observed in the 60 to −10 ppm chemical shift range. Comparison of the native and mutant N₂OR spectra recorded in H₂O-buffered solutions indicated that several additional signals are present in the native protein spectrum. These signals are attributed to a dinuclear copper(II) center. At least …

Induced Changes In Solvent Structure By Phospholipid Monolayer Formation At A Liquid–Liquid Interface, R. A. Walker, D. E. Gragson, G. L. Richmond

Chemistry and Biochemistry

Vibrational sum frequency spectroscopy has been used in conjunction with dynamic surface tension measurements to study formation of a 1,2-dilauroyl-sn-phosphatidylcholine (DLPC) monolayer at a water–carbon tetrachloride interface. Surface tension measurements show that an aqueous solution of liquid crystalline phosphocholine vesicles (4.5 μM DLPC) requires several hours to form a tightly packed, fully equilibrated monolayer of DLPC monomers. Vibrational spectra of the interfacial region at different stages in the monolayer formation process indicate that the solvent structure undergoes dramatic re-organization as the monolayer forms. Initial adsorption of DLPC monomers severely disrupts the interfacial hydrogen bonding. Intensity in the OH …

Analysis Of Galvanized Steel Plates Using Glow Discharge-Atomic Emission Spectrometry, Liang Wang

Masters Theses & Specialist Projects

Combining an intense emission source and a high-speed sputtering source in one, glow discharge atomic emission spectrometer (GD-AES) provides an efficient technique for analyzing surfaces, coatings and bulk solids. The purpose of our work is to explore the optimum lamp operation parameters of SA-2000 for analysis of galvanized steel plate and to investigate the method for qualitatively and quantitatively analyzing the zinc coating. Under the optimum experimental conditions found in our study, which are current of 19-21 mA; voltage of 900-1200 V; pressure 2.0-2.5 torr, the calibration curve is constructed, so that specific zinc concentration can be assign to the …

Comparison Of An Advanced Mercury Analyzer With The Cold Vapor Atomic Absorption Technique For The Determination Of Mercury In Coal, Dong Li

Masters Theses & Specialist Projects

For over 30 years the industry standard method for mercury analysis has been the cold vapor atomic absorption spectrometric technique (CVAAS). Recent developments in improving this technique have focused on procedures for concentrating mercury in the analyte or materials to improve detection. The LECO Corporation produces an Advanced Mercury Analyzer, the AMA-254, for analysis of the solid and liquid samples. The system allows for the thermal heating of the sample to decompose the sample and release mercury, which is concentrated in a gold amalgam. Thermal desorption of the mercury from the amalgam is detected by atomic absorption spectroscopy. A comparison …

Folding Dynamics Of Single Gcn-4 Peptides By Fluorescence Resonant Energy Transfer Confocal Microscopy, Yiwei Jia, David Talaga, Wai Leung Lau, Helen S.M. Lu, William F. Degrado, Robin M. Hochstrasser

Department of Chemistry and Biochemistry Faculty Scholarship and Creative Works

We have prepared a bichromophoric crosslinked variant of GCN4-P1 for single-molecule fluorescence energy transfer experiments (GCN4-Pf). The folding and unfolding fluctuations of single GCN4-Pf molecules are measured in a two-channel confocal microscope with which donor and acceptor fluorescence trajectories are measured simultaneously. The energy transfer efficiency is thereby determined and its probability distributions as a function of added denaturant [urea] are calculated. The distributions indicate that single molecule GCN4-Pf is in dynamic folding equilibrium with the position of the equilibrium being altered by the concentration of urea.

41st Rocky Mountain Conference On Analytical Chemistry

Rocky Mountain Conference on Magnetic Resonance

Final program, abstracts, and information about the 41st annual meeting of the Rocky Mountain Conference on Analytical Chemistry, co-sponsored by the Colorado Section of the American Chemical Society and the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Denver, Colorado, August 1-5, 1999.

Rank-Order Of Potencies For Inhibition Of The Secretion Of Aβ40 And Aβ42 Suggests That Both Are Generated By A Single Γ-Secretase, John T. Durkin, Seetha Murthy, E. Jean Husten, Stephen P. Trusko, Mary J. Savage, David Rotella, Barry D. Greenberg, Robert Siman

Department of Chemistry and Biochemistry Faculty Scholarship and Creative Works

The Alzheimer's disease amyloid peptide Aβ has a heterogeneous COOH terminus, as variants 40 and 42 residues long are found in neuritic plaques and are secreted constitutively by cultured cells. The proteolytic activity that liberates the Aβ COOH terminus from the β-amyloid precursor protein is called γ-secretase. It could be one protease with dual specificity or two distinct enzymes. By using enzyme-linked immunosorbent assays selective for Aβ40 or Aβ42, we have measured Aβ secretion by a HeLa cell line, and we have examined the dose responses for a panel of five structurally diverse γ- secretase inhibitors. The inhibitors lowered Aβ …

Protein Adducts Of Iso[4]Levuglandin E2, A Product Of The Isoprostane Pathway, In Oxidized Low Density Lipoprotein, Robert G. Salomon, Wei Sha, Cynthia Brame, Kamaljit Kaur, Ganesamoorthy Subbanagounder, June O'Neil, Henry F. Hoff, L. Jackson Roberts Ii

Pharmacy Faculty Articles and Research

Levuglandin (LG) E₂, a cytotoxic seco prostanoic acid co-generated with prostaglandins by nonenzymatic rearrangements of the cyclooxygenase-derived endoperoxide, prostaglandin H₂, avidly binds to proteins. That LGE₂-protein adducts can also be generated nonenzymatically is demonstrated by their production during free radical-induced oxidation of low density lipoprotein (LDL). Like oxidized LDL, LGE₂-LDL, but not native LDL, undergoes receptor-mediated uptake and impaired processing by macrophage cells. Since radical-induced lipid oxidation produces isomers of prostaglandins, isoprostanes (isoPs), via endoperoxide intermediates, we postulated previously that a similar family of LG isomers, isoLGs, is cogenerated with isoPs. Now …

Models For Molybdenum Coordination During The Catalytic Cycle Of Periplasmic Nitrate Reductase From Paracoccus Denitrificans Derived From Epr And Exafs Spectroscopy, Clive S. Butler, John M. Charnock, Brian Bennett, Heather J. Sears, Ann J. Reilly, Stuart J. Ferguson, C. David Garner, David J. Lowe, Andrew J. Thomson, Ben C. Berks, David J. Richardson

Physics Faculty Research and Publications

The periplasmic nitrate reductase from Paracoccus denitrificans is a soluble two-subunit enzyme which binds two hemes (c-type), a [4Fe-4S] center, and a bis molybdopterin guanine dinucleotide cofactor (bis-MGD). A catalytic cycle for this enzyme is presented based on a study of these redox centers using electron paramagnetic resonance (EPR) and extended X-ray absorption fine structure (EXAFS) spectroscopies. The Mo(V) EPR signal of resting NAP (High g [resting]) has g_av = 1.9898 is rhombic, exhibits low anisotropy, and is split by two weakly interacting protons which are not solvent-exchangeable. Addition of exogenous ligands to this resting …

Zinc Speculation And Ligand Fluxes In Chesapeake Bay And Elizabeth River Pore Waters, Duncan Glover Byers

Chemistry & Biochemistry Theses & Dissertations

Presented here are the first data on the vertical concentrations, complexation, speciation, and fluxes of total dissolved zinc and zinc complexing ligands, and zinc speciation in sediment pore waters in the Chesapeake Bay and Elizabeth River, Virginia.

Sediment pore waters were collected in mid and southern Chesapeake Bay in November 1997 and in the Elizabeth River (Pinner's Point) in March, April, and July 1998. Flux experiments were conducted in Elizabeth River sediment cores in April and July 1998. [TDZn] and zinc complexation were determined using differential pulse anodic stripping voltammetry at a hanging mercury drop electrode (DPASV-HMDE).

[TDZn] in the …

Intermediate Species Possessing Bent Dna Are Present Along The Pathway To Formation Of A Final Tbp-Tata Complex, Kay M. Parkhurst, Robyn M. Richards, Michael Brenowitz, Lawrence J. Parkhurst

Lawrence Parkhurst Publications

Binding of the TATA-binding protein (TBP) to the “TATA” sequences present in the promoters of eukaryotic class II genes is the first step in the sequential assembly of transcription pre-initiation complexes. Myriad structural changes, including severe bending of the DNA, accompany TBP-TATA complex formation. A detailed kinetic study has been conducted to elucidate the mechanistic details of TBP binding and DNA bending. The binding of Saccharomyces cerevisiae TBP to the adenovirus major late promoter (AdMLP) was followed in real-time through a range of temperatures and TBP concentrations using fluorescence resonance energy transfer (FRET) and stopped-flow mixing. The results of association …

High-Performance Liquid Chromatographic Separation Of Novel Atropic Α,Α-Disubstituted-Β-Amino Acids, Either On Different Β-Cyclodextrin-Bonded Phases Or As Their 1-Fluoro-2,4-Dinitrophenyl-5-L-Alanine Amide Derivatives, Gabriella Török, Antal Péter, Anne Gaucher, Michel Wakselman, Jean Paul Mazaleyrat, Daniel W. Armstrong

Chemistry Faculty Research & Creative Works

The high-performance liquid chromatographic enantioresolution of free and N- and/or C-protected derivatives of (R, S)-2',1':1,2;1',2':3,4-dinaphthcyclohepta-1,3-diene-6-aminomethyl-6 -carboxylic acid (β2-Bin) by direct and indirect methods is reported. The direct separation was carried out on native and different derivatized β -cyclodextrin-bonded phases. The indirect resolution was achieved by applying pre-column derivatization with 1-fluoro-2,4-dinitrophenyl-5-L-alanine amide. The effects of different parameters such as the mobile phase composition and the structures of the compounds on the enantiomeric resolution are discussed.

Methylene-Only Subspectra In 13C Cpmas Using A New Double Quantum Filtering Sequence, Paola Rossi, Raju Subramanian, Gerard S. Harbison

Gerard S. Harbison Publications

Methodology for the assignment of ¹³C CPMAS spectra is still in its infancy. Previous methods of CPMAS spectral editing have utilized differences in the strength of the ¹³C–¹H dipolar interaction or the rate and spin thermodynamics of crosspolarization from protons to carbon, to differentiate between quaternary, tertiary, and methylene carbons. We introduce a different approach, which is based on the fact that double-quantum coherence develops between the protons of a methylene group considerably faster than between most other proton spin pairs in an organic solid. We generate this coherence, filter it, convert it back to single …

Overview: Nonlinear Dynamics Related To Polymeric Systems, Irving R. Epstein, John A. Pojman

Faculty Publications

No abstract provided.

Oxidation And Adsorption Of Deoxyribonucleic Acid At Highly Ordered Pyrolytic Graphite And Glass Carbon Electrode, Jian-Zhang Zhou, Ling-Ling Wu, Jin Luo, Zhong-Hua Lin

Journal of Electrochemistry

It is shown that calf thymus DNA (CT DNA) can be adsorbed at highly ordered pyrolytic graphite (HOPG) electrode and detected by differential pulse voltammetry (DPV) and electrochemical atomic force microscopy (ECAFM). It is found that controlled potential pre-polarization influences largely the adsorption of dsDNA while it has little influence on ssDNA. It is demonstrated that ECAFM is useful to exploit adsorption of DNA at HOPGE. The pattern of adsorption of DNA at HOPG electrode that fits best with the experimental data is proposed. The results aslo shows that UV/Vis reflection spectroscopy, which has not been used in studying electrochemical …

Plant And Soil Enantioselective Biodegradation Of Racemic Phenoxyalkanoic Herbicides, J. M. Schneiderheinze, Daniel W. Armstrong, Alain Berthod

Chemistry Faculty Research & Creative Works

The biodegradation of the chiral phenoxyalkanoic herbicides 2-(2,4- dichlorophenoxy)propionic aid (2,4-DP) and 2-(4-chloro-2- methylphenoxy)propionic acid (MCPP) was investigated using enantioselective HPLC and chiroptical detection. Racemic mixtures of 2,4-DP and MCPP were applied to three species of turf grass, four species of broadleaf weeds, and soil. Preferential degradation of the S- (-) enantiomer of each herbicide was observed in most species of broadleaf weeds and soil, while the degradation in all species of grass occurred without enantioselectivity. The biodegradation in all systems appeared to follow pseudo first-order kinetics with the fastest degradation occurring in broadleaf weeds, followed by the grasses. The …

The Mean Spherical Approximation For A Dipolar Yukawa Fluid, Douglas Henderson, Dezso Boda, Istvan Szalai, Kwong-Yu Chan

Faculty Publications

The dipolar hard sphere fluid (DHSF) is a useful model of a polar fluid. However, the DHSF lacks a vapor–liquid transition due to the formation of chain-like structures. Such chains are not characteristic of real polar fluids. A more realistic model of a polar fluid is obtained by adding a Lennard–Jones potential to the intermolecular potential. Very similar results are obtained by adding a Yukawa potential, instead of the Lennard–Jones potential. We call this fluid the dipolar Yukawa fluid (DYF). We show that an analytical solution of the mean spherical approximation (MSA) can be obtained for the DYF. Thus, the …

Identification And Characterization Of Biological And Volatile Organic Contaminants In Indoor Air In A Governmental State Office Building, Denesia A. Wallace

Electronic Dissertations and Theses

The purpose of this study was to identify and determine the concentrations of targeted inorganic gases and total volatile organic compounds known to exist in indoor air spaces. The Louisiana Department of Environmental Quality (LADEQ) Office Building was selected because of a survey of occupants' symptoms and perceptions of indoor air quality. Collected air samples were analyzed for selected compounds by way of United States Environmental Protection Agency (USEPA) sampling procedures and methods that utilized drager absorption tubes and a gas chromatograph/mass spectrometer. The targeted compounds were nitrogen dioxide, dinitrogen oxide, carbon monoxide, VOCs (volatile organic compounds), formaldehyde, and carbon …

An Immobolized Surfactant Extraction Technique Compatible With High Performance Liquid Chromatography-Ultraviolet Visible Detection, Ming Zhu

Masters Theses & Specialist Projects

Surfactant mediated extractions are analogous to liquid-liquid extractions (LLE) except surfactants are used as extractants instead of organic solvents. The benefit for using surfactants for extractions includes lower toxicity, lower associated costs and direct compatibility with high performance liquid chromatography techniques. In this study, a novel immobilized surfactant extraction method was developed. In this method, the cationic alklytrimethylamrnonium surfactants are immobilized onto a strong cationic exchange resin through ion exchange. This surfactant-resin material is placed in a column and aqueous solutions containing analytes are passed through. The analytes are retained by the long carbon chain of the surfactant molecules and …

Reductive Dehydroxy Coupling Of 2-(Hydroxymethyl)Indenes To Prepare Ethano-Bridged Bis(2-Indenyl) Ansa-Titanocenes, Hasan Palandoken, Justin K. Wyatt, Shawn R. Hitchcock, Marilyn M. Olmstead, Michael H. Nantz

Chemistry and Biochemistry

New examples of ansa-titanocenes derived from 1,2-bis(2-indenyl)ethane have been prepared. The titanium-mediated reductive coupling of 2-(hydroxymethyl)indenes provided a convenient method for substrate dimerization. Alkyl substitution of the indene ring at C(3) improved the regioselectivity of the reductive coupling to provide the ethylene bis(2-indenyl)ansa-ligands in 29–62% yield.

Insight Into The Selectivity Of Molecular Imprinted Polymers, Thomas Patrick O'Brien

Seton Hall University Dissertations and Theses (ETDs)

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Thermodynamic And Binding Studies Of Ligand-Carcinogen Dna Targets, Qianying Liang

Seton Hall University Dissertations and Theses (ETDs)

No abstract provided.

The Role Of Iron And Reactive Oxygen Species In Particulate Air Pollution-Dependent Biochemical And Biological Activities, Kevin Richard Smith

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Particulate air pollution is known to exacerbate respiratory diseases, such as asthma and chronic obstructive pulmonary disease, in humans. It has been proposed that transition meta ls from inhaled particles may play a role in this exacerbation by generating radical species leading to damage in the lungs.

The aim of this research was to determine the role that iron from particulate air pollution played in the generation of reactive oxygen species and subsequently the induction of inflammatory mediators in cells in culture. The production of reactive oxygen species by particulate air pollution was found to be dependent on the mobilization …