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Articles 14401 - 14430 of 15526

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Auger Resonance Decay Process In Ar 2p Shell Excitation And Ionization, Y. Lu, Wayne C. Stolte, J.A. R. Samson Oct 1998

Auger Resonance Decay Process In Ar 2p Shell Excitation And Ionization, Y. Lu, Wayne C. Stolte, J.A. R. Samson

Chemistry and Biochemistry Faculty Research

The production and subsequent autoionization of the Ar+ (1D2)6d1 satellite state that is formed either by shake-up or recapture during the Auger decay of a 2p vacancy in Ar has been studied by photoelectron spectroscopy in the energy region from 243 to 256 eV. The creation of near zero energy electrons below and immediately above the Ar 2p ionization threshold is discussed. Some ambiguous points in previous studies are clarified.

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Interagency Lake Mead And Las Vegas Wash Monitoring Program: Standard Operating Procedures Manual, Bureau Of Reclamation, City Of Henderson Water Reclamation Facility, City Of Las Vegas Water Pollution Control Facility, Clark County Sanitation District, Nevada, Southern Nevada Water Authority Oct 1998

Interagency Lake Mead And Las Vegas Wash Monitoring Program: Standard Operating Procedures Manual, Bureau Of Reclamation, City Of Henderson Water Reclamation Facility, City Of Las Vegas Water Pollution Control Facility, Clark County Sanitation District, Nevada, Southern Nevada Water Authority

Publications (WR)

A number of agencies sample Lake Mead and the Las Vegas Wash on a routine basis at several locations. In order to share and properly interpret the data, the Bureau of Reclamation, Southern Nevada Water Authority and the three Wastewater Treatment Facilities (City of Las Vegas, Clark County Sanitation District and City of Henderson) formed a committee to examine sampling and analytical protocols and to share information with the goal of maximizing the data quality. The group first met in April 1997. It was agreed that an effort should be made to discuss and compare specific sampling and analytical techniques …

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Comparison Between Dc-8 And Er-2 Species Measurements In The Tropical Middle Troposphere: No, NoY, O3, Co2, Ch4, And N2O, A. J. Weinheimer, D. D. Montzka, T. L. Campos, J. G. Walega, B. A. Ridley, Stephen G. Donnelly Ph.D., E. R. Keim, L. A. Del Negro, M. H. Proffitt, J. J. Margitan, K. A. Boering, A. E. Andrews, B. C. Daube, S. C. Wofsy, B. E. Anderson, J. E. Collins, G. W. Sachse, S. A. Vay, J. W. Elkins, P. R. Wamsley, E. L. Atlas, F. Flocke, S. Schauffler, C. R. Webster, R. D. May, M. Loewenstein, J. R. Podolske, T. P. Bui, K. R. Chan, S. W. Bowen, M. R. Schoeberl, L. R. Lait Sep 1998

Comparison Between Dc-8 And Er-2 Species Measurements In The Tropical Middle Troposphere: No, NoY, O3, Co2, Ch4, And N2O, A. J. Weinheimer, D. D. Montzka, T. L. Campos, J. G. Walega, B. A. Ridley, Stephen G. Donnelly Ph.D., E. R. Keim, L. A. Del Negro, M. H. Proffitt, J. J. Margitan, K. A. Boering, A. E. Andrews, B. C. Daube, S. C. Wofsy, B. E. Anderson, J. E. Collins, G. W. Sachse, S. A. Vay, J. W. Elkins, P. R. Wamsley, E. L. Atlas, F. Flocke, S. Schauffler, C. R. Webster, R. D. May, M. Loewenstein, J. R. Podolske, T. P. Bui, K. R. Chan, S. W. Bowen, M. R. Schoeberl, L. R. Lait

Chemistry Faculty Publications

We compare measurements of six species taken aboard NASA DC-8 and ER-2 aircraft during two flight legs in the tropical middle troposphere near Hawaii. NO, NOy, O3, CH4, and N2O measurements agree to within the limits set by the known systematic errors. For CO2, which can be measured with better relative precision than the other five species, differences in measured values from the two platforms are slightly larger than expected if the air masses sampled by the two aircraft were indeed similar in CO2 composition to better than 0.08%. Copyright 1998 by the American Geophysical Union.

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Simultaneous Formation Of Functional Leading And Lagging Strand Holoenzyme Complexes On A Small, Defined Dna Substrate, Anthony J. Berdis, Stephen J. Benkovic Sep 1998

Simultaneous Formation Of Functional Leading And Lagging Strand Holoenzyme Complexes On A Small, Defined Dna Substrate, Anthony J. Berdis, Stephen J. Benkovic

Chemistry Faculty Publications

The biochemical characterization of leading and lagging strand DNA synthesis by bacteriophage T4 replication proteins has been addressed utilizing a small, defined primer/template. The ATP hydrolysis activity of 44/62, the clamp loading complex responsible for holoenzyme assembly, was monitored during assembly of both the leading and lagging strand holoenzyme complex. The ATPase activity of 44/62 diminishes once a functional holoenzyme is assembled on both the leading and lagging strand. The assembly of the lagging strand holoenzyme is facilitated by several factors including biotinylated streptavidin blocks at the end of the fork strands, preassembly of the leading strand holoenzyme, and by …

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Chemical Signals From Submarine Fluid Advection Onto The Continental Shelf, W. S. Moore, Timothy J. Shaw Sep 1998

Chemical Signals From Submarine Fluid Advection Onto The Continental Shelf, W. S. Moore, Timothy J. Shaw

Faculty Publications

No abstract provided.

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Immunological Relationship Between The Class I Epitope Of Streptococcal M Protein And Myosin, Anthony Quinn, Kent Ward, Vincent A. Fischetti, Mark E. Hemric, Medeleine W. Cunningham Sep 1998

Immunological Relationship Between The Class I Epitope Of Streptococcal M Protein And Myosin, Anthony Quinn, Kent Ward, Vincent A. Fischetti, Mark E. Hemric, Medeleine W. Cunningham

Faculty Publications and Presentations

The class I epitope of streptococcal M protein is an epidemiological marker for acute rheumatic fever (ARF)-associated serotypes of group A streptococci and is recognized by anti-M protein monoclonal antibody (MAb) 10B6. Using MAb 10B6, we determined the relationship between the class I epitope of M protein and the a-helical coiled-coil protein myosin. MAb 10B6 reacted by enzyme-linked immunosorbent assay and Western blotting with human cardiac myosin and rabbit skeletal myosin and its heavy meromyosin (HMM) subfragment. Overlapping synthetic peptides of M5 protein were used to identify the region of M5 protein recognized by MAb 10B6. Two C repeat peptides …

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Effects Of N-Acetylcysteine And 2,3-Dimercaptosuccinic Acid On Lead Induced Oxidative Stress In Rat Lenses, Rachel Neal, Katherine Cooper, Nuran Ercal, Hande Gürer-Orhan Sep 1998

Effects Of N-Acetylcysteine And 2,3-Dimercaptosuccinic Acid On Lead Induced Oxidative Stress In Rat Lenses, Rachel Neal, Katherine Cooper, Nuran Ercal, Hande Gürer-Orhan

Chemistry Faculty Research & Creative Works

Lead (Pb) is known to disrupt the pro-oxidant/anti-oxidant balance of tissues which leads to biochemical and physiological dysfunction. The present study investigated the previous termeffectsnext term of exposure on the redox status of the lenses of Fisher 344 rats and examined whether antioxidant or chelator administration reversed these changes. Animals were given 5 weeks of 2000 ppm Pb exposure followed by 1 week of either antioxidant, chelator or distilled water administration. Glutathione (GSH) and cysteine (CYS) levels decreased in the Pb-exposed group. N-previous termacetylcysteinenext term or 2,3-dimercaptopsuccinic previous termacidnext term (Succimer) supplementation following Pb intoxication resulted in increases in the …

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Localization Of Sodium, Potassium-Adenosine Triphosphatase In The Cerebral Cortex Of Developing Rats, Maki Ujiie Sep 1998

Localization Of Sodium, Potassium-Adenosine Triphosphatase In The Cerebral Cortex Of Developing Rats, Maki Ujiie

Loma Linda University Electronic Theses, Dissertations & Projects

Active transport via Na+, K+-ATPase plays an important role in establishing and maintaining proper ionic gradient across all mammalian cell membranes. A strict regulation of Na+, and K+ ion levels is especially important in excitable cells such as neurons and myocytes. Inhibition of the enzyme is associated with several pathological conditions and has serious detrimental effects on cerebral cortical cells. Yet the enzyme appears to be limited in amount and distribution in newborn rats. In this study, Na+, K+- ATPase expression and distribution in early postnatal rats were studied …

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Direct Voltammetric Observation Of Redox Driven Changes In Axial Coordination And Intramolecular Rearrangement Of The Phenylalanine-82-Histidine Variant Of Yeast Iso-1-Cytochrome C, Benjamin A. Feinberg, Xiangjun Liu, Michael D. Ryan, Abel Schejter, Chongyao Zhang, Emanuel Margoliash Sep 1998

Direct Voltammetric Observation Of Redox Driven Changes In Axial Coordination And Intramolecular Rearrangement Of The Phenylalanine-82-Histidine Variant Of Yeast Iso-1-Cytochrome C, Benjamin A. Feinberg, Xiangjun Liu, Michael D. Ryan, Abel Schejter, Chongyao Zhang, Emanuel Margoliash

Chemistry Faculty Research and Publications

Direct square-wave and cyclic voltammetric electrochemical examination of the yeast iso-1-cytochrome c Phe82His/Cys102Ser variant revealed the intricacies of redox driven changes in axial coordination, concomitant with intramolecular rearrangement. Electrochemical methods are ideally suited for such a redox study, since they provide a direct and quantitative visualization of specific dynamic events. For the iso-1-cytochrome c Phe82His/Cys102Ser variant, square-wave voltammetry showed that the primary species in the reduced state is the Met80-Fe2+-His18 coordination form, while in the oxidized state the His82-Fe3+-His18 form predominates. The addition or removal of an electron to the …

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Detergent-Salt Resistance Of Lap2Α In Interphase Nuclei And Phosphorylation-Dependent Association With Chromosomes Early In Nuclear Assembly Implies Functions In Nuclear Structure Dynamics, Thomas Dechat, Josef Gotzmann, Andreas Stockinger, Crafford A. Harris, Mary Ann Talle, John Siekierka, Roland Foisner Aug 1998

Detergent-Salt Resistance Of Lap2Α In Interphase Nuclei And Phosphorylation-Dependent Association With Chromosomes Early In Nuclear Assembly Implies Functions In Nuclear Structure Dynamics, Thomas Dechat, Josef Gotzmann, Andreas Stockinger, Crafford A. Harris, Mary Ann Talle, John Siekierka, Roland Foisner

Department of Chemistry and Biochemistry Faculty Scholarship and Creative Works

Lamina-associated polypeptide (LAP) 2 of the inner nuclear membrane (now LAP2β) and LAP2α are related proteins produced by alternative splicing, and contain a common 187 amino acid N-terminal domain. We show here that, unlike LAP2β, LAP2α behaved like a nuclear non-membrane protein in subcellular fractionation studies and was localized throughout the nuclear interior in interphase cells. It co-fractionated with LAP2β in nuclear lamina/matrix-enriched fractions upon extraction of nuclei with detergent, salt and nucleases. During metaphase LAP2α dissociated from chromosomes and became concentrated around the spindle poles. Furthermore, LAP2α was mitotically phosphorylated, and phosphorylation correlated with increased LAP2α solubility upon extraction …

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Highly Enantioselective Hplc Separations Using The Covalently Bonded Macrocyclic Antibiotic, Ristocetin A, Chiral Stationary Phase, K. Helen Ekborg-Ott, Youbang Liu, Daniel W. Armstrong Aug 1998

Highly Enantioselective Hplc Separations Using The Covalently Bonded Macrocyclic Antibiotic, Ristocetin A, Chiral Stationary Phase, K. Helen Ekborg-Ott, Youbang Liu, Daniel W. Armstrong

Chemistry Faculty Research & Creative Works

The macrocyclic glycopeptide, ristocetin A, was covalently bonded to a silica gel support and evaluated as a liquid chromatographic (LC) chiral stationary phase (CSP). Over 230 racemates were resolved in either the reversed-phase mode, the normal-phase mode, or the polar-organic mode. The retention behavior and selectivity of this CSP were examined in each mode. Optimization of separations on this column is discussed. The ristocetin A CSP appeared to be complimentary to other glycopeptide CSPs (i.e., vancomycin and teicoplanin). Column stability was excellent. The CSP was not irreversibly altered when going from one mobile phase mode to another.

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The Effects Of So2 On The Formation Of Cl2 During Co-Firing Muncipal Solid Waste With Coal, Ying Xie Aug 1998

The Effects Of So2 On The Formation Of Cl2 During Co-Firing Muncipal Solid Waste With Coal, Ying Xie

Masters Theses & Specialist Projects

The Deacon Reaction was proposed as a mechanism for the formation of molecular chlorine during the combustion of municipal solid waste (MSW): 4HCl + O2 ↔ 2Cl2 + 2H2O As suggested by some researchers, co-firing high sulfur coal with MSW may reduce the emission of toxic chlorinated organics, resulting from the reaction between S02 and Cl2: SO2 + Cl2 + H2O → SO3 + 2HCl The effect of sulfur dioxide on the formation of chlorine through the Deacon Reaction is investigated in this study. A Lindberg Furnace was utilized and preheated to 800°C to simulate the conditions in the AFBC …

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Enantiomeric Separation Of Unusual Secondary Aromatic Amino Acids, A. Péter, G. Török, G. Tóth, W. Van Den Nest, G. Laus, D. Tourwé, Daniel W. Armstrong Jul 1998

Enantiomeric Separation Of Unusual Secondary Aromatic Amino Acids, A. Péter, G. Török, G. Tóth, W. Van Den Nest, G. Laus, D. Tourwé, Daniel W. Armstrong

Chemistry Faculty Research & Creative Works

High-performance liquid chromatographic and gas chromatographic methods were developed for the separation of unusual secondary aromatic amino acids. Amino acids containing 1,2,3,4-tetrahydroisoquinoline, 1,2,3,4-tetrahydronorharmane-1-carboxylic acid and 1,2,3,4-tetrahydro-3-carboxy-2-carboline moieties were synthetized in racemic or chiral forms. The high-performance liquid chromatography was carried out either on a teicoplanin-containing chiral stationary phase or on an achiral C18 column. In the latter case the diastereomers of the amino acids formed by precolumn derivatization with the chiral reagents 2,3,3,6-tetra-O-acetyl-β-D-glucopyranosyl isothiocyanate or 1-fluoro-2,4-dinitrophenyl-5-L-alanine amide were separated. The gas chromatographic analyses were based on separation on a Chirasil-L-Val column.

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40th Rocky Mountain Conference On Analytical Chemistry Jul 1998

40th Rocky Mountain Conference On Analytical Chemistry

Rocky Mountain Conference on Magnetic Resonance

Final program, abstracts, and information about the 40th 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, July 25 - August 1, 1998.

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Role Of The Maillard Reaction In Aging Of Tissue Proteins: Advanced Glycation End Product-Dependent Increase In Imidazolium Cross-Links In Human Lens Proteins, Elisabeth Brinkmann Frye, Thorsten P. Degenhardt, Suzanne R. Thorpe, John W. Baynes Jul 1998

Role Of The Maillard Reaction In Aging Of Tissue Proteins: Advanced Glycation End Product-Dependent Increase In Imidazolium Cross-Links In Human Lens Proteins, Elisabeth Brinkmann Frye, Thorsten P. Degenhardt, Suzanne R. Thorpe, John W. Baynes

Faculty Publications

Dicarbonyl compounds such as glyoxal and methylglyoxal are reactive dicarbonyl intermediates in the nonenzymatic browning and cross-linking of proteins during the Maillard reaction. We describe here the quantification of glyoxal and methylglyoxal-derived imidazolium cross-links in tissue proteins. The imidazolium salt cross-links, glyoxal-lysine dimer (GOLD) and methylglyoxal-lysine dimer (MOLD), were measured by liquid chromatography/mass spectrometry and were present in lens protein at concentrations of 0. 02-0.2 and 0.1-0.8 mmol/mol of lysine, respectively. The lens concentrations of GOLD and MOLD correlated significantly with one another and also increased with lens age. GOLD and MOLD were present at significantly higher concentrations than the …

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The Extraction And Coordination Chemistry Of An Organophosphorus Ligand: The Synthesis And Characterization Of Organophosphorus Ligands And Dendrimers Using The Michael-Type Addition, Evelyn M. Bond Jul 1998

The Extraction And Coordination Chemistry Of An Organophosphorus Ligand: The Synthesis And Characterization Of Organophosphorus Ligands And Dendrimers Using The Michael-Type Addition, Evelyn M. Bond

Chemistry and Chemical Biology ETDs

In chapter 1, the liquid/ liquid extraction of americium (III) from nitric and hydrochloric acid solutions with chloroform solutions of 2, 6 bis[(diphenylphosphino)methyl]pyridine N, P, P' trioxide (ENOPOPO) is examined. Americium (III) is efficiently extracted from aqueous solutions at high nitric acid concentrations (DAm > 3000 at 6 M HNO3) and can be totally back extracted from the organic phrase at 0.01 M HNO3. The ligand dependency data suggest that two ligand molecules are coordinated to the americium. From hydrochloric acid solutions, ENPOPO exhibits modest extraction ability for americium (III) (DAm = 2.2 at 5 M …

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Covalently Functionalized Nanotubes As Nanometer-Sized Probes In Chemistry And Biology, Stanislaus S. Wong, Ernesto Joselevich, Adam T. Woolley, Chin Li Cheung, Charles M. Lieber Jul 1998

Covalently Functionalized Nanotubes As Nanometer-Sized Probes In Chemistry And Biology, Stanislaus S. Wong, Ernesto Joselevich, Adam T. Woolley, Chin Li Cheung, Charles M. Lieber

Barry Chin Li Cheung Publications

Carbon nanotubes combine a range of properties that make them well suited for use as probe tips in applications such as atomic force microscopy (AFM)1, 2, 3. Their high aspect ratio, for example, opens up the possibility of probing the deep crevices4 that occur in microelectronic circuits, and the small effective radius of nanotube tips significantly improves the lateral resolution beyond what can be achieved using commercial silicon tips5. Another characteristic feature of nanotubes is their ability to buckle elastically4, 6, which makes them very robust while limiting the maximum force that is …

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Determination Of The N-Terminal Amino Acid Residues On Polypeptides In Secondary Wastewaters, Edward L. Creecy Jul 1998

Determination Of The N-Terminal Amino Acid Residues On Polypeptides In Secondary Wastewaters, Edward L. Creecy

Chemistry & Biochemistry Theses & Dissertations

The N-terminal amino acid residues on polypeptides and proteins were determined in wastewaters prior to chlorination. The terminal amino groups'ere first derivatized with the well known derivatizing agent dansyl chloride, and then the resulting dansyl amino acid hydrolyzed from the peptide chain by a propionic acid/ hydrochloric acid mixture. The resulting dansyl amino acids were then separated and detected using reversed phase high performance liquid chromatography with fluorescence detection. The majority of N-terminal residues detected were the more polar amino acids. Concentrations ranged from 1 x 10-10 to 3 x 10-7 moles/liter. It is suggested that the shorter …

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Interleukin (Il)-1 Receptor-Associated Kinase (Irak) Requirement For Optimal Induction Of Multiple Il-1 Signaling Pathways And Il-6 Production, Palanisamy Kanakaraj, Peter H. Schafer, Druie E. Cavender, Ying Wu, Karen Ngo, Patrick F. Grealish, Scott A. Wadsworth, Per A. Peterson, John Siekierka, Crafford A. Harris, Wai Ping Fung-Leung Jun 1998

Interleukin (Il)-1 Receptor-Associated Kinase (Irak) Requirement For Optimal Induction Of Multiple Il-1 Signaling Pathways And Il-6 Production, Palanisamy Kanakaraj, Peter H. Schafer, Druie E. Cavender, Ying Wu, Karen Ngo, Patrick F. Grealish, Scott A. Wadsworth, Per A. Peterson, John Siekierka, Crafford A. Harris, Wai Ping Fung-Leung

Department of Chemistry and Biochemistry Faculty Scholarship and Creative Works

Interleukin (IL)-1 is a proinflammatory cytokine with pleiotropic effects in inflammation. IL-1 binding to its receptor triggers a cascade of signaling events, including activation of the stress-activated mitogen- activated protein (MAP) kinases, c-Jun NH2-terminal kinase (JNK) and p38 MAP kinase, as well as transcription factor nuclear factor κB (NF-κB). IL-1 signaling results in cellular responses through induction of inflammatory gene products such as IL-6. One of the earliest events in IL-1 signaling is the rapid interaction of IL-1 receptor-associated kinases, IRAK and IRAK-2, with the receptor complex. The relative roles of IRAK and IRAK-2 in IL-1 signaling pathways and subsequent …

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Solute-Solvent Pair Distribution Functions In Highly Asymmetric Additive Hard Sphere Mixtures, Douglas Henderson, Kwong-Yu Chan Jun 1998

Solute-Solvent Pair Distribution Functions In Highly Asymmetric Additive Hard Sphere Mixtures, Douglas Henderson, Kwong-Yu Chan

Faculty Publications

Contact values for the solute-solvent pair distribution function in an additive hard sphere mixture, as computed from the Henderson-Chan (HC) formulas, are compared with the recent Monte Carlo (MC) data and formula of Matyushov and Ladanyi (ML) [J. Chem. Phys. 107, 5815 (1997)]. The agreement is found to be excellent. The negative finding of ML is due to a misprint in one of the HC publications. We find the HC formula to be superior to the ML formula when compared to our MC data [Mol. Phys. 91, 1137 (1997)] for the case where the ratio of diameters is large and …

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In Vitro Cytotoxicity Study Of Glutaraldehyde And No-React Treated Bioprosthetic Heart Valves And The Aortic Wall, Roger Ongosi May 1998

In Vitro Cytotoxicity Study Of Glutaraldehyde And No-React Treated Bioprosthetic Heart Valves And The Aortic Wall, Roger Ongosi

Theses

Valvular failure due to calcification and leaflet disruption of artificial bioprostheses is still a major concern in valve replacement surgery. Previous studies have shown that Glutaraldehyde, a chemical used in the treatment of artificial valves promotes calcification. In this investigation glutaraldehyde and No-React® treated tissue samples of pericardium, cusp and the aortic wall were tested for cytocompatibility using live mouse fibroblast cultures. The samples were cut into 3 X 3 mm2 washed in phosphate buffered saline solution, transferred into cell culture flask containing cells that had been cultured for 24 hours and incubated at 37 "C in 5 % CO2. …

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New Esr-Electrochemical Cell Designs For Coaxial Microwave Cavity, Lin Zhuang, Jun-Tao Lu May 1998

New Esr-Electrochemical Cell Designs For Coaxial Microwave Cavity, Lin Zhuang, Jun-Tao Lu

Journal of Electrochemistry

New cell designs for simultaneous electrochemical (EC) and electron spin resonance (ESR) measurements are reported for coaxial microwave cavity. Adjustable shieldings are introduced so that the working electrode can be much shorter than the full height of the cavity. Besides the traditional helical electrode, the working electrode can be cylinders made from metal plates, metallic meshes or even composite materials. The counter electrode can be placed either inside or outside the cavity. These features make the new designs more flexible than that previously reported. With a nonperforated cylindrical electrode, this cell can be used to determine the standard potential and …

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Molecular Design And Association Constants Of Nizatidine-Guest Complexes, Elizabeth Corbeil May 1998

Molecular Design And Association Constants Of Nizatidine-Guest Complexes, Elizabeth Corbeil

Honors Theses

Nizatidine, N-[2-[[[2-[(dimethylamino)metbyl]-4-thiazolyl]methyl]thio]ethyl]-N'methyl- 2-nitro-l,l-ethenediamine (Axid"), has been investigated for its potential to act as a host in guest-host complexes. Nizatidine binds with the guests through hydrogen bonding and pi-pi interactions. Guest-host studies were conducted using fluorescence quenching, calorimetry, NMR and invisible experiments. The lowest energy conformation of nizatidine is found to be U-shaped through theoretical calculations. Fluorescence experiments indicated that tryptophan and pyridoxine had large association constants. Further studies using calorimetry and NMR techniques concluded that no complexation had occurred. Complexation experiments have been done to find guests that complex with nizatidine. Caffeine, luminol, nicotinamide, phenylalanine, pyridoxine, pyrogallol, and tryptophan were …

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Quantitative And Stereoisomeric Determination Of Light Biomarkers In Crude Oil And Coal Samples, Alain Berthod, Xiande Wang, Kyung H. Gahm, Daniel W. Armstrong May 1998

Quantitative And Stereoisomeric Determination Of Light Biomarkers In Crude Oil And Coal Samples, Alain Berthod, Xiande Wang, Kyung H. Gahm, Daniel W. Armstrong

Chemistry Faculty Research & Creative Works

Indans and tetralins are considered biological markers (biomarkers). These C9-C11 hydrocarbons are present in small amounts in organic geological samples. Methyl substituted indans or tetralins may possess a stereogenic center (carbon). Thus they can exist as enantiomers and, in the case of disubstituted enties, also as diastereoisomers. The concentrations of 1-methylindan, 1,3-dimethylindan, 1-methyltetralin, and 2-methyltetralin were determined in 16 crude oil samples of different sources and in 14 coal samples of different sources and ranks. Deuterated homologues were synthesized as standards to spike the samples and to assure accurate quantitative analysis. A procedure using HPLC fractionation followed by GC/MS analysis …

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Determination Of Intracellular Glutathione Concentration Using Monobromobimane, Ryan R. Owens May 1998

Determination Of Intracellular Glutathione Concentration Using Monobromobimane, Ryan R. Owens

Undergraduate Honors Capstone Projects

Asbestos is a general term for a group of fibrous silicates. Diseases such as asbestosis, bronchogenic carcinoma, and mesothelioma have been linked to asbestos exposure (1,2). The 1 two classes of asbestos, serpentine and amphibole, are distinguished by differences in structure and chemical composition (3). The amphibole crocidolite contains 27% iron while the serpentine chrysotile contains only 2-3% iron. The higher iron content of crocidolite is proposed to be a contributing factor for a much higher incidence of cancer with crocidolite exposure compared with chrysotile exposure ( 4). Iron mobilized intracellularly from asbestos fibers may participate in the formation of …

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Distance Dependence Of Electron Transfer Along Artificial Β-Strands At 298 And 77 K, S. R. L. Fernando, Gennady V. Kozlov, Michael Y. Ogawa Apr 1998

Distance Dependence Of Electron Transfer Along Artificial Β-Strands At 298 And 77 K, S. R. L. Fernando, Gennady V. Kozlov, Michael Y. Ogawa

Chemistry Faculty Publications

Photoinduced electron-transfer rate constants were measured for a series of binuclear metallopeptides consisting of a [Ru(bpy)(2)(cmbpy)](2+) electron donor tethered to a Co-III(NH3)(5) electron acceptor by an oligovaline peptide chain (bpy = 2,2'-bipyridine, cmbpy = 4-carboxy-4'-methyl-2,2'-bipyridine). These compounds were shown by H-1 NMR to adopt the conformational properties found within the individual strands of a beta-pleated sheet in both aqueous and methanol solutions. Emission lifetime measurements and HPLC product analysis show that the binuclear donor/acceptor compounds undergo photoinduced electron transfer (ET). The values of k(et) decrease with increasing donor/acceptor distance according to the expression k(et) = k' exp[-beta(r(-)r(0))]. A distance attenuation …

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Explosive Vapor Generation And Sampling In Conjunction With Ion Mobility Spectrometry, Saeed H. Almeer Apr 1998

Explosive Vapor Generation And Sampling In Conjunction With Ion Mobility Spectrometry, Saeed H. Almeer

Chemistry & Biochemistry Theses & Dissertations

The primary objective of this research is to develop an inexpensive and reliable method to generate vapor pulses of explosives using 2,4,6-trinitrotoluene TNTl for proof of concept. A secondary objective is to demonstrate the use of the vapor generator in various applications keeping in mind potential field scenarios involving explosives. A vapor generator/collector system was developed which gives reproducible pulses of TNT vapors at nanogram levels. The use of this technology was demonstrated in evaluating different surfaces for vapor adsorption of TNT in conjunction with ion mobility spectrometry as the primary analytical tool. Of the materials examined, Teflon was by …

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Neutral Dissociation Of Hydrogen Following Photoexcitation Of Hcl At The Chlorine K Edge, D. L. Hansen, J. Cotter, G. R. Fisher, K. T. Leung, R. Martin, Paul Neill, Rupert C. Perera, I. A. Sellin, Marc Simon, Y. Uehara, B. Vanderford, S. B. Whitfield Apr 1998

Neutral Dissociation Of Hydrogen Following Photoexcitation Of Hcl At The Chlorine K Edge, D. L. Hansen, J. Cotter, G. R. Fisher, K. T. Leung, R. Martin, Paul Neill, Rupert C. Perera, I. A. Sellin, Marc Simon, Y. Uehara, B. Vanderford, S. B. Whitfield

Chemistry and Biochemistry Faculty Research

Time-of-flight mass spectroscopy was used to study the relaxation dynamics of HCl following photoexcitation in the vicinity of the Cl K edge (~2.8 keV) using monochromatic synchrotron radiation. At the lowest resonant excitation to the 6ơ* antibonding orbital, almost half of the excited molecules decay by emission of a neutral H atom, mostly in coincidence with a highly charged Cln1 ion. The present work demonstrates that neutral-atom emission can be a significant decay channel for excited states with very short lifetimes (1 fs). [S1050-2947(98)03604-X]

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A Cell Cycle-Regulated Adenine Dna Methyltransferase From Caulobacter Crescentus Processively Methylates Gantc Sites On Hemimethylated Dna, Anthony J. Berdis, Irene Lee, James K. Coward, Craig Stephens, Rachel Wright, Lucy Shapiro, Stephen J. Benkovic Mar 1998

A Cell Cycle-Regulated Adenine Dna Methyltransferase From Caulobacter Crescentus Processively Methylates Gantc Sites On Hemimethylated Dna, Anthony J. Berdis, Irene Lee, James K. Coward, Craig Stephens, Rachel Wright, Lucy Shapiro, Stephen J. Benkovic

Chemistry Faculty Publications

The kinetic properties of an adenine DNA methyltransferase involved in cell cycle regulation of Caulobacter crescentus have been elucidated by using defined unmethylated or hemimethylated DNA (DNAHM) substrates. Catalytic efficiency is significantly enhanced with a DNAHM substrate. Biphasic kinetic behavior during methyl incorporation is observed when unmethylated or DNAHM substrates are used, indicating that a step after chemistry limits enzyme turnover and is most likely the release of enzyme from methylated DNA product. The enzyme is thermally inactivated at 30°C within 20 min; this process is substantially decreased in the presence of saturating concentrations of DNAHM, suggesting that the enzyme …

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Double Photoionization Of Helium, James A.R. Samson, Wayne C. Stolte, Z. X. He, Y. Lu, J. N. Cutler, R. J. Bartlett Mar 1998

Double Photoionization Of Helium, James A.R. Samson, Wayne C. Stolte, Z. X. He, Y. Lu, J. N. Cutler, R. J. Bartlett

Chemistry and Biochemistry Faculty Research

The cross sections for double photoionization of helium and the ratios of double to single ionization have been measured from the double-ionization threshold to 820 eV. The results are in very good agreement with several recent calculations.

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