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Articles 30871 - 30900 of 34550

Full-Text Articles in Physical Sciences and Mathematics

Peroxyoxalate Chemiluminescence And Capillary Electrophoresis : New Methods For Bioanalytical Chemistry, Nian Wu Apr 1993

Peroxyoxalate Chemiluminescence And Capillary Electrophoresis : New Methods For Bioanalytical Chemistry, Nian Wu

Graduate Dissertations and Theses

The general research objectives lie in the development of new approaches to improve chemical analysis in the area of bioanalytical chemistry. More specifically this thesis is focused on the development and application of new methodologies and instrumentation involving two potentially powerful techniques: 1) Chemiluminescence-a spectroscopic technique in which the generation of fluorescence from the electronically excited state of the molecule is provided by a chemical reaction and 2) Capillary electrophoresis-a separation technique in which small ions as well as large biomolecules can be separated with high efficiency within a narrow capillary under the influence of high voltage.

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Chlorination Products Of Glycylphenylalanine In Model Solutions And A Wastewater, Daniel J. Keefe Apr 1993

Chlorination Products Of Glycylphenylalanine In Model Solutions And A Wastewater, Daniel J. Keefe

Chemistry & Biochemistry Theses & Dissertations

Model solutions of the dipeptide glycylphenylalanine were chlorinated to five different chlorine-to-amino nitrogen (Cl/N) mole ratios and analyzed after 30 min by high performance liquid chromatography. At mole ratios of ≤ 1, N-chloroglycylphenylalanine (I) appeared to be the only major product. At a mole ratio ≤ 2, N, N-dichloroglycylphenylalanine (II) was the only product. Compound II decomposes in model solutions (t1/2= 6.4 hr) at pH 7.0 to form a compound tentatively identified as an H-chloroaldimine (III). Compound III in turn decomposes (t1/2= 36 hr) in model solutions at pH 7. o to (IV) . From 13 …

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Quantitative Determination Of Surface Excess By The Semiintegral Method, Susanne Dana, Mathew Jablonski, Mark Anderson Mar 1993

Quantitative Determination Of Surface Excess By The Semiintegral Method, Susanne Dana, Mathew Jablonski, Mark Anderson

Mark R. Anderson

In 1988 Bowling and McCreery reported that the semiintegral of voltammetric data provided an excellent method for the qualitative diagnosis of weak adsortpion of material upon an electrode. This report was important to electroanalytical chemistry because of the difficulty often encountered when trying to identify the presence of weakly adsorbed material and because of the impact that weak adsorption has upon voltammetric response. Many electrochemical analyses are dependent upon the evaluation of voltammetric wave shape, particularly kinetic analyses. Unlike strong adsorption, the presence of weakly adsorbed material does not dramatically and obviously perturb the shape of the voltammetric response; consequently, …

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Studies Of The Solid-Phase Pauson-Khand Reaction Selective In-Situ Enone Reduction To 3-Azabicyclo[3.3.0]Oct-Anones, Daniel Becker, Daniel L. Flynn Mar 1993

Studies Of The Solid-Phase Pauson-Khand Reaction Selective In-Situ Enone Reduction To 3-Azabicyclo[3.3.0]Oct-Anones, Daniel Becker, Daniel L. Flynn

Chemistry: Faculty Publications and Other Works

The Smit-Caple DSAC Pauson-Khand cyclization of a series of N-protected allyl propargyl amines in the absence of oxygen gave rise to formation of the saturated azabicyclo[3.3.0]octanones in excellent yields. Standard cyclization in air gave mixtures of saturated and unsaturated ketones.

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Isolation Of A Highly Functionalized Troeger’S Base Derivative Via A Novel Reaction, Daniel Becker, Patricia M. Finnegan, Paul W. Collins Mar 1993

Isolation Of A Highly Functionalized Troeger’S Base Derivative Via A Novel Reaction, Daniel Becker, Patricia M. Finnegan, Paul W. Collins

Chemistry: Faculty Publications and Other Works

Heating a solution of methyl 5-chloro-4-[(ethoxyoxoacetyl) amino]-2-methoxybenz-oate, 3 in DMSO gave rise to the formation of the highly substitute

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Multifragment Emission In 36ar +197au And 129xe + 197au Collisions, W. Bauer, D. R. Bowman, N. Carlin, N. Colonna, R. T. De Souza, C. K. Gelbke, W. G. Gong, K. Hanold, Y. D. Kim, M. A. Lisa, W. G. Lynch, M. A. Mcmahan, L. G. Moretto, Graham F. Peaslee, L. Phair, M. B. Tsang, C. Williams, G. J. Wozniak, F. Zhu Mar 1993

Multifragment Emission In 36ar +197au And 129xe + 197au Collisions, W. Bauer, D. R. Bowman, N. Carlin, N. Colonna, R. T. De Souza, C. K. Gelbke, W. G. Gong, K. Hanold, Y. D. Kim, M. A. Lisa, W. G. Lynch, M. A. Mcmahan, L. G. Moretto, Graham F. Peaslee, L. Phair, M. B. Tsang, C. Williams, G. J. Wozniak, F. Zhu

Faculty Publications

Multifragment disintegrations observed in 36Ar+197Au and 129Xe+197Au collisions are compared with theoretical predictions.

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2-Carboxybenzenediazonium Chloride Monohydrate, Christopher J. Horan, Charles Leslie Barnes, Rainer Glaser Mar 1993

2-Carboxybenzenediazonium Chloride Monohydrate, Christopher J. Horan, Charles Leslie Barnes, Rainer Glaser

Chemistry Faculty Research & Creative Works

C7H5N2O2 +.Cl-H2O, Mr = 202.60, monoclinic, C2c, a = 25.62(3), b = 4.964(2), c = 14.900 (14)Å, β = 107.15 (4)°, V = 1811 (3)Å3, Z = 8, Dx = 1.486 g cm-3, λ(Mo Kα) = 0.71073 Å, µ = 3.9 cm-1, F(000) = 832, T = 298 K, R = 0.035 for 1275 observed reflections. The terminal N atom of the diazonium group is bent away from the carboxyl group. The N2 and the …

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Microscale-Liquid Chromatographic Determination Of Pungent Compounds, Maha Khaled, Mark Anderson, L. Marquez, Harold Mcnair Feb 1993

Microscale-Liquid Chromatographic Determination Of Pungent Compounds, Maha Khaled, Mark Anderson, L. Marquez, Harold Mcnair

Mark R. Anderson

No abstract is currently available.

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Solid-State Structures Of N-Butyllithium-Tmeda, -Thf, And -Dme Complexes., Michael Nichols, Paul Williard Feb 1993

Solid-State Structures Of N-Butyllithium-Tmeda, -Thf, And -Dme Complexes., Michael Nichols, Paul Williard

Michael A Nichols

No abstract provided.

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Use Of Infrared Spectroscopy To Probe Analytical Surfaces, Mark Anderson Feb 1993

Use Of Infrared Spectroscopy To Probe Analytical Surfaces, Mark Anderson

Mark R. Anderson

No abstract is available at this time.

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Use Of Infrared Spectroscopy To Probe Analytical Surfaces, Mark Anderson Feb 1993

Use Of Infrared Spectroscopy To Probe Analytical Surfaces, Mark Anderson

Mark R. Anderson

No abstract is available at this time.

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Expansion Effects In Intermediate Energy Heavy-Ion Reactions, R. T. De Souza, D. Fox, W. A. Friedman, L. Phair, D. R. Bowman, C. K. Gelbke, W. G. Gong, Y. D. Kim, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, M. B. Tsang, F. Zhu Feb 1993

Expansion Effects In Intermediate Energy Heavy-Ion Reactions, R. T. De Souza, D. Fox, W. A. Friedman, L. Phair, D. R. Bowman, C. K. Gelbke, W. G. Gong, Y. D. Kim, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, M. B. Tsang, F. Zhu

Faculty Publications

Transverse kinetic energy spectra of fragments in the reaction 36Ar + 197Au are used to probe the multifragmentation mechanism at intermediate energies. The mass dependence of the average transverse kinetic energy is examined in the context of the statistical decay of an expanding, emitting source. The role of source expansion during emission is explored. Results suggest the onset of volume emission at the highest incident energy.

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Insertion Reactions Of Monovalent Silicon: A Nonvanishing Barrier For The Silylidyne Plus Hydrogen Reaction Sih + H2, Mark S. Gordon, Yaoming Xie, Yukio Yamaguchi, Roger S. Grev, Henry F. Schaefer Iii Feb 1993

Insertion Reactions Of Monovalent Silicon: A Nonvanishing Barrier For The Silylidyne Plus Hydrogen Reaction Sih + H2, Mark S. Gordon, Yaoming Xie, Yukio Yamaguchi, Roger S. Grev, Henry F. Schaefer Iii

Mark S. Gordon

Ab initio quantum mechanical methods have been applied to the SiH (X zrr) insertion into the Hz molecule. The transition state has no elements of symmetry. The classical barrier height is predicted to be 5.6 :I: I kcaljmol. The barrier is qualitatively consistent with an estimate from Jasinski's experimental reaction rates, which are much slower than those observed for the related CH + Hz, SiH + SiH4, and SiH2 + Hz reactions.

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Extraction Of The Multifragmentation Time Scale In Intermediate Energy Heavy-Ion Reactions, D. Fox, R. T. De Souza, L. Phair, D. R. Bowman, N. Carlin, C. K. Gelbke, W. G. Gong, Y. D. Kim, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, M. B. Tsang, F. Zhu Feb 1993

Extraction Of The Multifragmentation Time Scale In Intermediate Energy Heavy-Ion Reactions, D. Fox, R. T. De Souza, L. Phair, D. R. Bowman, N. Carlin, C. K. Gelbke, W. G. Gong, Y. D. Kim, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, M. B. Tsang, F. Zhu

Faculty Publications

The spatial and temporal extent of a system decaying by multifragment emission is deduced. Two-particle intermediate mass fragment correlation functions measured for central Ar36+197Au collisions at E/A=50–110 MeV indicate a rapid decay, <75 fm/c, of the highly excited system. Furthermore, the behavior of the correlation function at large relative velocities suggests that considerable charge loss occurs prior to fragment emission.

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Multiplet-Changing Auger Transitions In Valence Double Photoionization, U. Becker, Oliver Hemmers, B. Langer, I. Lee, A. Menzel, R. Wehlitz, M. Ya Amusia Feb 1993

Multiplet-Changing Auger Transitions In Valence Double Photoionization, U. Becker, Oliver Hemmers, B. Langer, I. Lee, A. Menzel, R. Wehlitz, M. Ya Amusia

Environmental Studies Faculty Publications

The decay of valence satellite states in neon above the first double-ionization threshold has been studied experimentally and theoretically. Special emphasis was given to differentiate between two decay modes: valence Auger and valence-multiplet Auger decay. It is shown that the latter process is predominant in the low kinetic energy part of the spectrum. The main structures of this low-energy Auger spectrum could be designated by help of calculated transition energies and decay rates.

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The Electrochemical Characterization Of A Platinum Cyclooctadiene Complex As A Guest Molecule In The Presence Of Ss-Cyclodextrin, Timothy S. Evenson Jan 1993

The Electrochemical Characterization Of A Platinum Cyclooctadiene Complex As A Guest Molecule In The Presence Of Ss-Cyclodextrin, Timothy S. Evenson

Opportunities for Undergraduate Research Experience Program (OURE)

The equilibrium constants for the complexation of the dichloroplatinum- cycloocta-1,5-diene complex with p-cyclodextrin in N,N-dimethyl- formamide was determined using electrochemical cyclic voltammetry. The constants for both the oxidized and reduced forms of the platinum compound were determined. Model redox experiments were conducted with ferrocene and 1,1 ’-dimethylferrocene before the platinum compound was studied in order to establish parameters for the experimental method. Also determined was the ratio of the diffusion constants of the guest molecule with and without being complexed with cyclodextrin. In addition to the platinum complex being electrochemically characterized as a guest of cyclodextrin, circular dichroism studies were …

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Hypochlorite Oxidation Of Nitrilotriacetic Acid, Audrey P. Linville Jan 1993

Hypochlorite Oxidation Of Nitrilotriacetic Acid, Audrey P. Linville

Opportunities for Undergraduate Research Experience Program (OURE)

The chemical degradation of nitrilotriacetic acid (NTA) by sodium hypochlorite is examined. Preliminary work indicates that NTA undergoes decarboxylation. In the second phase of this investigation (S92), the work was mainly concerned with the products from the reaction of NTA with hypochlorite. The product of decarboxylation has been found to be iminodiacetic acid. The decrease in concentration of hypochlorite per unit time was studied over a pH range of 7-14 and in the presence of lead, calcium, zinc, and copper ions.

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Complex Fragment Production In 139la-Induced Reactions At 35, 40, 45, And 55 Mev/Nucleon, P. Roussel-Chomaz, N. Colonna, Y. Blumenfeld, B. Libby, Graham F. Peaslee, D. N. Delis, K. Hanold, M. A. Mcmahan, J. C. Meng, Q. C. Sui, G. J. Wozniak, L, G. Moretto, H. Madani, A. A. Marchetti, A. C. Mignery, G. Guarino, N. Santoruvo, I. Iori, S. Bradley Jan 1993

Complex Fragment Production In 139la-Induced Reactions At 35, 40, 45, And 55 Mev/Nucleon, P. Roussel-Chomaz, N. Colonna, Y. Blumenfeld, B. Libby, Graham F. Peaslee, D. N. Delis, K. Hanold, M. A. Mcmahan, J. C. Meng, Q. C. Sui, G. J. Wozniak, L, G. Moretto, H. Madani, A. A. Marchetti, A. C. Mignery, G. Guarino, N. Santoruvo, I. Iori, S. Bradley

Faculty Publications

Complex fragment emission (Z>3) has been studied in the reactions of 35, 40, 45 and 55 MeV/u139La+X. Charge, angular, and energy distributions were measured inclusively and in coincidence with other complex fragments, and were used to extract source rapidities, velocity distributions, and cross sectins. Multifragment events increase with both bombarding energy and entrance-channel mass asymmetry. The excitation functions for multifragment events rise strongly with excitation energy. These excitation functions are independent of the target-projectile combination and bombarding energy suggesting, the formation of an intermediate nuclear system, whose decay properties depend mainly on its excitation energy and angular momentum.

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A Clay Modified Electrode For Ion-Exchange Voltammetry, Thaddeus S. Wielgos Jan 1993

A Clay Modified Electrode For Ion-Exchange Voltammetry, Thaddeus S. Wielgos

Master's Theses

No abstract provided.

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Nmr Study Of Na+-H+ And Na+-Li+ Exchange In Human Erythrocytes, Suilan Mo Jan 1993

Nmr Study Of Na+-H+ And Na+-Li+ Exchange In Human Erythrocytes, Suilan Mo

Master's Theses

No abstract provided.

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Correlation Of 17o Chemical Shifts Of Chromium Carbene Complexes With Moss' Mxy Reacitvity Parameter, Shuyuan Liao Jan 1993

Correlation Of 17o Chemical Shifts Of Chromium Carbene Complexes With Moss' Mxy Reacitvity Parameter, Shuyuan Liao

Master's Theses

No abstract provided.

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The Interaction Of Sickle Hemoglobin With Phosphatidylserine Vesicles ; Fourier Transform Infrared Spectroscopic Studies Of Human Erythrocyte Spectrin, Cynthia C. Labrake Jan 1993

The Interaction Of Sickle Hemoglobin With Phosphatidylserine Vesicles ; Fourier Transform Infrared Spectroscopic Studies Of Human Erythrocyte Spectrin, Cynthia C. Labrake

Dissertations

No abstract provided.

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A Facile Route To Allylic Phosphonates Via Base-Catalyzed Isomerization Of The Corresponding Vinyl Phosphonates : Remote Dianions In Synthesis, Synthetic Approaches To The Indolizidines, James J. Kiddle Jan 1993

A Facile Route To Allylic Phosphonates Via Base-Catalyzed Isomerization Of The Corresponding Vinyl Phosphonates : Remote Dianions In Synthesis, Synthetic Approaches To The Indolizidines, James J. Kiddle

Dissertations

No abstract provided.

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Catecholamine Secretion In Bovine Chromaffin Cells : Influence Of Immune-Derived Factors, Zhaohui Wang Jan 1993

Catecholamine Secretion In Bovine Chromaffin Cells : Influence Of Immune-Derived Factors, Zhaohui Wang

Master's Theses

No abstract provided.

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Homogeneous Nucleation In Supersaturated Vapors Of Polar Molecules: Acetonitrile, Benzonitrile, Nitromethane, And Nitrobenzene, D. Wright, R. Caldwell, C. Moxely, M. S. El-Shall Jan 1993

Homogeneous Nucleation In Supersaturated Vapors Of Polar Molecules: Acetonitrile, Benzonitrile, Nitromethane, And Nitrobenzene, D. Wright, R. Caldwell, C. Moxely, M. S. El-Shall

Chemistry Publications

The critical supersaturations (S c ) required for the homogeneous nucleation of acetonitrile, benzonitrile, nitromethane, and nitrobenzene vapors have been measured over wide temperature ranges using a thermal diffusion cloud chamber. At T r =0.44, the experimental results are higher than the predictions of the classical nucleation theory by 20% (CH3NO2), 50% (CH3CN), 57% (C6H5NO2), and 112% (C6H5CN). This trend correlates well with the dipole moments and to a lesser extent with the polarizabilities of these substances. Corresponding states of simple fluids and …

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Analysis Of Homogeneous Nucleation Data Of Polar Molecules: Vapor Association, Dipole Orientation, And Elongated Clusters, D. Wright, M. S. El-Shall Jan 1993

Analysis Of Homogeneous Nucleation Data Of Polar Molecules: Vapor Association, Dipole Orientation, And Elongated Clusters, D. Wright, M. S. El-Shall

Chemistry Publications

In this paper we present the results of several theoretical models examined in order to explain the observed systematic deviations of the homogeneous nucleation of highly polar substances from the predictions of the classical nucleation theory (CNT). It is found that molecular association in acetronitrile or nitromethane vapor cannot explain the observed higher supersaturations. Similarly, the use of virial coefficient data to obtain a size dependent surface energy correction factor does not reproduce the experimental results. It is shown that orientation of the surface dipoles within the spherical droplets results in higher supersaturations in agreement with the experimental findings. We …

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Processes For Producing Doxorubicin, Daunomycinone, And Derivatives Of Doxorubicin, Desmond M. S. Wheeler Jan 1993

Processes For Producing Doxorubicin, Daunomycinone, And Derivatives Of Doxorubicin, Desmond M. S. Wheeler

Chemistry Department: Faculty Publications

To produce doxorubicin and its analogues methyl 3alpha, 5alpha-dihydroxy-5beta-(trimethylsilylethynyl)- 2alpha-nitromethylcyclohexane-1beta-carboxylate acetonide is condensed with 1,4-dihydro-4,4,5-trimethoxy-1-oxonaphthalene in the presence of 1,8-diazabicyclo-5.4.0]undec-7-ene in an aprotic solvent to produce 3-(2beta-carbomethoxy-4-beta-ethynyl-4-alpha, 6alpha-(di-O-isopropylidenyl)cyclohexanyl-1-yl)-nitromethyl-4,4,5-trimethoxy-1-oxo-1,2,3,4-tetrahydronaphthalene; which is cyclized to produce 9beta ethynyl-12-hydroxy-7alpha, 9alpha-(di-O-iso propylidenyl)-6-nitro-4,5,5-trimethoxy-5,5a,6- 6a,7,8,9,10,10a,11-decahydro -11-naphthacenone. The decahydro-11-naphthacenone is converted to 7alpha 9alpha,(di-O-isopropyl-idenyl)-4,5-dimethoxy-9beta ethynyl-12-hydroxy-6-nitro-6,6a,7,8,9,10,10a, 11 octahydro-11, -naphthacenone. The octahydro-11 naphthacenone is oxidized to 7alpha-9alpha, (di-O-iso propyl-idenyl)-9beta-ethynyl-11-hydroxy-4-methoxy-6- nitro-7,8,9,10-tetrahydro-5,12-naphthacenedione which is converted to 6-desoxy-6-nitrodaunomycinone, daunomycinone and related 6-substituted analogues of daunomycinone.

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Soluble Highly Reactive Form Of Calcium And Reagents Thereof, Reuben D. Rieke Jan 1993

Soluble Highly Reactive Form Of Calcium And Reagents Thereof, Reuben D. Rieke

Chemistry Department: Faculty Publications

A soluble highly reactive form of calcium, prepared from Ca(II) salts and a reducing agent in ethereal, polyethereal, or hydrocarbon solvents, is presented. This form of calcium can be used in the preparation of organocalcium reagents. The organocalcium reagents resulting from the reaction of the soluble highly reactive calcium with organic compounds containing either halide, cyanide, a 1,3-diene, or a polyunsaturated functionality, are stable, useful reagents for organic synthesis. The organocalcium halide reagents undergo Grignard-type reactions. They also undergo reactions with Cu(I) salts to form organocalcium cuprate reagents. The organocalcium cuprate reagents undergo a variety of cross-coupling reactions. The soluble …

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Preparation And Use Of (2-Butene-1,4-Diyl)Magnesium Complexes In Organic Synthess, Reuben D. Rieke Jan 1993

Preparation And Use Of (2-Butene-1,4-Diyl)Magnesium Complexes In Organic Synthess, Reuben D. Rieke

Chemistry Department: Faculty Publications

The magnesium complexes of cyclic hydrocarbons, such as 1,2-dimethylenecycloalkanes, are readily prepared in high yields using highly reactive magnesium. Reactions of these (2-butene-1,4-diyl)magnesium reagents with electrophiles such as dibromoalkanes, alkyl ditosylates, or bromoalkylnitriles serve as a convenient method for synthesizing spirocyclic systems. Significantly, spirocarbocycles prepared by this method contain functional groups such as the exocyclic double bond or a keto group in one of the rings which could be used for further elaboration of these molecules. Furthermore, fused bicyclic systems containing a substituted five-membered ring can be conveniently prepared at high temperatures by the reactions of (2-butene-1,4- diyl)magnesium complexes with …

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Synthesis, Characterization, And Crystal Structure Of The (Η5-C5ph5)Cr(Co)3 Radical, Ray J. Hoobler, Marc A. Hutton, Mills M. Dillard, Michael Castellani, Arnold L. Rheingold, Anne L. Rieger, Philip H. Rieger, Thomas C. Richards, William E. Geiger Jan 1993

Synthesis, Characterization, And Crystal Structure Of The (Η5-C5ph5)Cr(Co)3 Radical, Ray J. Hoobler, Marc A. Hutton, Mills M. Dillard, Michael Castellani, Arnold L. Rheingold, Anne L. Rieger, Philip H. Rieger, Thomas C. Richards, William E. Geiger

Chemistry Faculty Research

The reaction between Cr(CO)6 and Na(C5Ph5 ) in refluxing diglyme yields [Na(diglyme)3/2][(C5Ph5)Cr(CO)3], 1. Metathesis of 1 with [Ph3P=N=PPh3 ]Cl in CH2Cl2 yields [Ph3P=N=PPh3][(C5Ph5)Cr(CO)3], 2. Oxidation of 1 by AgBF4 in cold THF under an argon atmosphere produces (C5Ph5)Cr(CO)3, 3. Complexes 2 and 3 form a redox pair connected by a quasireversible one-electron process, E0 = -0.69 V vs ferrocene in CH2Cl2, …

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