Physical Sciences and Mathematics Commons^™

Polymer Science In Austria Ii: Universities In Vienna, Otto Vogl, Josef Schurz

Otto Vogl

No abstract provided.

The 2′-Phosphate Of Nadp Is Critical For Optimum Productive Binding To 6-Phosphogluconate Dehydrogenase From Candida Utilis, Anthony J. Berdis, Paul F. Cook

Chemistry Faculty Publications

Initial velocity studies obtained with alternative dinucleotide substrates for the 6-phosphogluconate dehydrogenase reaction suggest that the 2′-phosphate is critical for the optimum productive binding of the dinucleotide substrate. Initial velocity patterns obtained by varying 6-phosphogluconate at different fixed levels of NAD are nearly parallel with apparent competitive substrate inhibition by 6-phosphogluconate at pH 7 and below but intersect to the left of the ordinate at pH 8 and above. Dead-end inhibition studies indicate that the mechanism is random at all pH values. Data are interpreted in terms of a random mechanism with marked antagonism in the binding of NAD and …

Vadose Zone Contamination Measurement And Modeling, Thomas A. Reeder

Theses and Dissertations

This thesis investigated the effects of the slow sorption mechanism on the transport of volatile organic contaminants in the vadose zone. Recent research has shown that slow sorption may have a significant impact on the transport of volatile organic compounds in the subsurface. Specifically, this document examined the effects of slow sorption on the Vapor Extraction System (VES) and the Purge and Trap Measurement System. It was found that the slow sorption of organic molecules on soil may profoundly influence the efficiency of VES and purge and trap. In addition, this thesis investigated possible alternatives to purge and trap, including …

Distance Dependence Of Nonadiabaticity In The Branching Between C–Br And C–Cl Bond Fission Following 1[N(O),Π∗(C=O)] Excitation In Bromopropionyl Chloride, P. W. Kash, G.C.G. Waschewsky, L. J. Butler, Michelle M. Francl

Chemistry Faculty Research and Scholarship

These experiments on bromopropionyl chloride investigate a system in which the barrier to C-Br fission on the lowest 1A'' potential energy surface is formed from a weakly avoided electronic configuration crossing, so that nonadiabatic recrossing of the barrier to C-Br fission dramatically reduces the branching to C-Br fission. The results, when compared with earlier branching ratio measurements on bromoacetyl chloride, show that the additional intervening CH2 spacer in bromopropionyl chloride reduces the splitting between the adiabatic potential energy surfaces at the barrier to C-Br fission, further suppressing C-Br fission by over an order of magnitude. The experiment measures the photofragment …

Sds Non-Acrylamide Polymeric Gel-Filled Capillary Electrophoresis For Molecular Size Separation Of Protein, Devon Andres

Honors Theses

Sodium dodecyl sulfide (SDS) non-acrylamide gel-filled capillary columns are a new technology being used for analysis and separation of biotechnology-derived proteins. This research was to compare this new technology to the current methods of SDS polyacrylamide gel electrophoresis (SDS-PAGE) and high-performance size-exclusion chromatography (HPSEC). The molecular mass of four different recombinant proteins were determined by two commercialized SDS non-acrylamide gel-filled capillary columns, SDS-PAGE, and HPSEC. The data obtained showed that the SDS non-acrylamide gel-filled capillary columns were compatible with the SDS-PAGE technique for molecular mass determination. HPSEC was shown to be unreliable for molecular weight determination. SDS non-acrylamide gel-filled capillary …

Does Methane Invert Through Square Planar?, Mark S. Gordon, Michael Schmidt

Mark S. Gordon

MCSCF calculations using a triple-t basis set augmented with diffuse and polarization functions are used to probe that part of the singlet methane potential energy surface that pertains to the inversion of CH4 from one t~trahedral structure t.o another. The true inversion transition state is found to have a distorted C, structure, quite different both ge?me.tncally ~nd energetically from the previously presumed square planar saddle point. At the secondorder configuration mte.ractl~n.level of theory, the barrier to inversion is predicted to be just 7-8 kcaljmol higher in energy than the bond diSSOCiation energy for the first C-H bond cleavage in methane.

Polymer Science In Austria Iii, Universities In Linz, Innsbruck And Other Research Institute In Austria Including Industry, Otto Vogl, Josef Schurz

Otto Vogl

No abstract provided.

Orientational Phase Transition In Na_{X}C_{60} (1, T. Yildirim, J. E. Fischer, A. B. Harris, Peter W. Stephens, Dengfa Liu, Laurent Brard, Robert M. Strongin, Amos B. Smith Iii

Chemistry Faculty Publications and Presentations

X-ray diffraction and calorimetry data on cubic Na_xC₆₀(1<x60, e.g., T_m(x=1.3)=325 K. The ordered phases are the same as in pure C₆₀: simple cubic, space group Pa3¯, but the orientations in the disordered phase are more restricted. We explain how Na stabilizes the ordered phase to rather high T, while K and Rb do not, in terms of Coulomb interactions between C₆₀ molecules and and Na ions which we calculate from the local charge density of C₆₀.

Observation Of Non-Isotropic Auger Angular Distribution In The C(1s) Shape Resonance Of Co, Oliver Hemmers, Franz Heiser, J. Eiben, R. Wehlitz, U. Becker

Environmental Studies Faculty Publications

Angle-resolved high-resolution C(KVV) Auger spectra of CO were taken in the vicinity of the C(1s) σ^* shape resonance. These spectra show clear evidence for the theoretically predicted anisotropic K-shell Auger emission in molecules. Complementary results from angle-resolved photoion spectroscopy show that the small size of the observed effect is, besides the varying intrinsic anisotropy of the Auger decay, also due to a smaller anisotropy in the primary absorption process than originally predicted but in good agreement with more recent calculations. Contrary to this, satellite Auger transitions show unexpectedly large anisotropies.

Radially Symmetrical Flow Of Reacting Liquid With Changing Viscosity, S.E. Solovyov, V.A. Volpert, S.P. Davytan

Faculty Publications

Frontal regimens for one-dimensional flow of reacting liquid with changing viscosity are studied. Stationary solutions are investigated for the case of narrow reaction zones that shrink to a front. The results of numerical solution of the nonstationary problem are presented. Complex oscillations resulting from period-doubling bifurcations are found.

Symmetrically H-Bridged Dimer Of 2-Carboxylatobenzenediazonium. The 1:1 Complex Between 2-Carboxybenzenediazonium Chloride And Benzenediazonium-2-Carboxylate, Christopher J. Horan, Paul E. Haney, Charles Leslie Barnes, Rainer Glaser

Chemistry Faculty Research & Creative Works

The two zwitterions in the H-bridged dimer of 2-carboxylatobenzenediazonim (1) are linked by a crystallographically symmetric O⋯Hctdot;O hydrogen bond with an O⋯O distance of 2.436 (3) Å. Comparison of the (1) with the other benzenediazonium salts shows that the phenyl ring distortions in (1) are determined primarily by the diazonium substituent with only modest additional effects by the carboxylato group. Intramolecular neighboring goup interactions between the N₂ group and the orthoCOO(H) group are indicated and are discussed. The terminal N atom of the diazonium group is bent away from the neighboring carboxylato group. The N₂ and the …

Thermal Analysis Of Bismaleimide/Graphite Fiber Composite By Tg/Ftir, Qi Zhang

Masters Theses & Specialist Projects

The purpose of this project was to study the thermal and oxidative stability of a specific polymer composite. A TG/FTIR combined technique was employed to characterize this polymer/graphite fiber composite. The polymer composite sample was decomposed in nitrogen, air, and 3% oxygen atmospheres in a Seiko thermogravimetric analyzer. The use of a gas cell Fourier-transform IR spectrometer downstream from the TGA allowed for the identification of evolved gas products.

The thermal oxidative stability (TOS) of this composite was compared to its thermal stability. Also, comparison of the TOS in different atmospheres was made. In addition, the effects of specimen geometry …

35th Rocky Mountain Conference On Analytical Chemistry

Rocky Mountain Conference on Magnetic Resonance

Program, abstracts, and information about the 35th 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 25-29, 1993.

Microemulsion Characterization By The Use Of A Noninvasive Backscatter Fiber Optic Probe, Rafat R. Ansari, Harbans S. Dhadwal, Michael Cheung, William V. Meyer

Chemical, Biomolecular, and Corrosion Engineering Faculty Research

This paper demonstrates the utility of a noninvasive backscatter fiber optic probe for dynamic light-scattering characterization of a microemulsion comprising sodium dodecyl sulfate/1-butanol/brine/heptane. The fiber probe, comprising two optical fibers precisely positioned in a stainless steel body, is a miniaturized and efficient self-beating dynamic light-scattering system. Accuracy of particle size estimation is better than +/- 2%.

Electronegativity And Bond Type 2. Evaluation Of Electronegativity Scales, Gordon Sproul

Faculty Publications

No abstract provided.

Tribological Characteristics Of Perfluoropolyether Liquid Lubricants Under Sliding Conditions In High Vacuum, Masabumi Masuko, William R. Jones Jr, Larry S. Helmick

Science and Mathematics Faculty Publications

Tribological characteristics of three PFPE's (Fomblin Z, Demnum, and Krytox) were studied under high vacuum using a four-ball apparatus with 440C steel specimens. Fomblin Z and Demnum exhibited initial scuffing-like high friction whereas Krytox did not. Steady state friction with Fomblin Z was the lowest among the three oils. Frictional values for Demnum and Krytox were almost the same. The lowest wear rate in air was provided by Krytox regardless of load, and low wear rates in vacuum at high load were achieved with Krytox and Demnum. Results are explained by reactivity and pressure-viscosity characteristics of the oils.

A Neutron Diffraction And Mössbauer Effect Study Of The Magnetic Properties Of Pr₂Fe₁₇ And Pr₂Fe₁₇N₂.₆, Gary J. Long, Oran Allan Pringle, Fernande Grandjean, William B. Yelon, K. H. Buschow

Chemistry Faculty Research & Creative Works

The neutron diffraction powder patterns of Pr₂Fe₁₇ and Pr₂Fe₁₇N_2.6 have been measured at 295 K and refined within the Th₂Zn₁₇ structure type to give the structural changes which occur upon nitrogenation; changes which include a 6.4% expansion of the unit cell volume. The Mössbauer spectra of Pr ₂Fe₁₇ and Pr₂Fe₁₇N_2.6 have been measured between 85 and 295 K and analyzed with a model which is based on the Wigner-Seitz cell environment of each iron site, the basal orientation of the magnetization, and …

Characterization Of Combustion Profiles Of Co-Fired Coal/Biomass/Limestone Samples By Tg And Tg/Ftir, Erik Jon Hutchinson

Masters Theses & Specialist Projects

Recent concerns over declining landfill space and a renewed interest in waste-to-energy technologies have increased the possibilities of co-firing different types of fuels in fluidized bed combustion systems. Fluidized bed combustion systems are idea for co-firing because of their ease in heat conversion and ability to burn a wide range of fuels. Additionally, thermal analytical techniques can be used to screen fuel blends for the fluidized bed combustion systems at a lower cost than directly firing the fuel blends in pilot systems. Three coals, three different municipal solid wastes (MSW), one limestone were combined into nine series of binary fuel …

The Isolation And Identification Of Polyphenolics From Grape Seeds And Their Activity Towards Specific Cell Lines, Joseph A. Reddy

Chemistry & Biochemistry Theses & Dissertations

Grape seed extract is being marketed in France for cardiovascular use and skin care. The active constituents of both these drugs are certain polyphenols called procyanidins. A similar seed extract has now been obtained from Virginia Chardonnay grape seeds. Ten of the major components in this extract have been isolated in their pure form by the semi-preparative HPLC separation on a YMC ODS-AQ (Octadecylsilane-AQ) column. The ODS-Aq column has been shown to have a better resolving capacity compared to the Spherisorb ODS (Octadecylsilane) column previously described in the literature. This has been attributed to the ODSAQ support which has both …

A Study Of The Chlorination Products Of Methionine In Model Solutions And In Wastewater, D. Scott Winters

Chemistry & Biochemistry Theses & Dissertations

Model solutions of the amino acid methionine were chlorinated to seven chlorine-to-nitrogen (Cl₂/N) molar ratios. After 30 minutes, the solutions were analyzed by high performance liquid chromatography (HPLC). At a Cl₂/N molar ratio of 1, methionine sulfoxide was found to be the main product. At Cl₂/N molar ratios ≥ 2, a mixture of methionine sulfoxide, methionine sulfone, an unidentified sulfoxide (product 1), and N-chloro-3-(methylsulfonyl) propionaldimine are formed. These products were identified by comparison to synthesized standards which were characterized by ¹H-NMR and ¹³C-NMR nuclear magnetic resonance spectroscopy, ion trap mass spectroscopy, …

Formation Of O-Tyrosine And Dityrosine In Proteins During Radiolytic And Metal-Catalyzed Oxidation, Thomas G. Huggins, Mary C. Wells-Knecht, Nicholas A. Detorie, John W. Baynes, Suzanna R. Thorpe

Faculty Publications

To evaluate their usefulness as chemical indicators of cumulative oxidative damage to proteins, we studied the kinetics and extent of formation of ortho-tyrosine (0-Tyr), dityrosine (DT), and dityrosine-like fluorescence (Ex = 3 17 nm, E,,, = 407 nm) in the model proteins RNase and lysozyme exposed to radiolytic and metalcatalyzed (H20z/Cu2+) oxidation (MCO). Although there were protein-dependent differences, o-Tyr, DT, and fluorescence increased coordinately during oxidation of the proteins in both oxidation systems. The contribution of DT to total dityrosine-like fluorescence in oxidized proteins varied from 2-10070, depending on the protein, type of oxidation, and extent of oxidative damage. In …

Oxidized Amino Acids In Lens Protein With Age: Measurement Of O-Tyrosine And Dityrosine In The Aging Human Lens, Mary C. Wells-Knect, Thomas G. Huggins, Daniel G. Dyer, Suzanne R. Thorpe, John W. Baynes

Faculty Publications

The concentrations of ortho-tyrosine (o-Tyr) and dityrosine (DT) were measured in noncataractous human lenses in order to assess the role of proteinoxidation reactions in the aging of lens proteins. The measurements were conducted by selected ion monitoring-gas chromatography/mass spectrometry using deuterium-labeled internal standards, which provided both high sensitivity and specificity for the quantitation of o-Tyr and DT. Between ages 1 and 78 years, the o-Tyr concentration in lens proteins varied from 0.3 to 0.9 mmol of o-Tyr/mol of Phe (n = 19), while DT ranged from 1 to 3 mumol of DT/mol of Tyr (n = 30). There were no …

The Cytotoxic Effect Of Tropical Plants On Human And Rat Hepatoma Cells, Mark Tafazoli

Honors Capstone Projects and Theses

No abstract provided.

Experimental And Computational Studies Of Four-Coordinate Aluminum: The Reaction Of Aluminates And Acids, Robert Damrauer, Michèle Krempp, Niels H. Damrauer, Michael W. Schmidt, Mark S. Gordon

Mark S. Gordon

The gas-phase reactions of trimethylaluminates with a variety of acids are considered from both an experimental and computational perspective. The experimental work involves product and kinetic studies of ten aluminates, [(CH3hAlX]- (X= H, CH3, NH2, OH, F, SiH3, PH2, SH, Cl, and OCH3). Both X and methyl cleavage pathways are observed in these reactions. X cleavage occurs with several aluminates (X = H, NH2, OH, and PH2), in contrast to the thermochemical predictions of ab initio computations performed at the MP2/6-31 ++G(d,p) level. These indicate that methyl cleavage is favored in the reaction of nine aluminates (OCH3 was not computed) …

The Selective Oxidation Of Dihydrosilanes, Paul B. Gansle Jr.

Honors Theses

The synthesis of drugs and natural products in enartiomerically pure form is a growing area of research. Our laboratory is currently working on synthetic methodologies that would facilitate the production of compounds in such a form. The approach we are taking is to use chiral silanes as templates for the stereochemical control of organic reactions. In order to do this, however, we must first synthesize these silanes enantiomerically pure. This project focuses on the synthesis of chiral silanes by selective oxidation of prochiral dihydrosilanes to yield directly, or by further transformations, halohydrosilanes. These halohydrosilanes can in turn, be used as …

Construction Of A Compact, Versatile Diode Laser Spectrometer And Characterization Of Dye-Surfactant Interactions, Marc Alexander Unger

Honors Theses

A compact diode laser spectrometer has been designed and built. A diode laser serves as a light source. The sample holder was designed to allow the mounting of optical filters and focusing optics. These optical filters differentiate between transmitted, scattered, and fluorescent light. A photodiode transduces one of these optical signals to a current signal. The electronics were designed to perform current to voltage conversion, amplify the signal, and filter out noise. Further processing and display are performed by a "Virtual Instrument", which is a computer program designed to simulate a physical instrument. Design methodology for the mechanical/optical, electronic, and …

The Development And Testing Of An Instrument For Doing Fast Time-Resolved Infrared Spectroscopy And The Study Of Dimanganese Decacarbonyl Using Uv/Vis And Ftrir Spectroscopic Techniques, Steven Wells Kinne

Honors Theses

Over the past three years at Union College, an instrument has been developed that can be used to probe the mechanisms of the photochemistry of transition metal carbonyl compounds. When these complexes are activated with photons, one or two carbonyl ligands are removed from the complex, opening these sites for chemical bonding. Thus, the coordinatively unsaturated species become catalytically active, and can catalyze a wide variety of organic reactions. The intermediates in these catalytic cycles tend to be short-liver lifetimes are usually less than one second), and therefore special instrumnetation must be developed in order to directly observe these intermediates …

Maillard Reaction Products And Their Relation To Complications In Insulin-Dependent Diabetes Mellitus, David R. Mccance, Daniel G. Dryer, John A. Dunn, Karen E. Bailie, Suzanne R. Thorpe, John W. Baynes, Timothy J. Lyons

Faculty Publications

Glycation, oxidation, and browning of proteins have all been implicated in the development of diabetic complications. We measured the initial Amadori adduct, fructoselysine (FL); two Maillard products, N epsilon-(carboxymethyl) lysine (CML) and pentosidine; and fluorescence (excitation = 328 nm, emission = 378 nm) in skin collagen from 39 type 1 diabetic patients (aged 41.5 +/- 15.3 [17-73] yr; duration of diabetes 17.9 +/- 11.5 [0-46] yr, [mean +/- SD, range]). The measurements were related to the presence of background (n = 9) or proliferative (n = 16) retinopathy; early nephropathy (24-h albumin excretion rate [AER24] > or = 20 micrograms/min; n …

Accumulation Of Maillard Reaction Products In Skin Collagen In Diabetes And Aging, Daniel G. Dyer, John A. Dunn, Suzanne R. Thorpe, Karen E. Bailie, Timothy L. Lyons, David R. Mccance, John W. Baynes

Faculty Publications

To investigate the contribution of glycation and oxidation reactions to the modification of insoluble collagen in aging and diabetes, Maillard reaction products were measured in skin collagen from 39 type 1 diabetic patients and 52 nondiabetic control subjects. Compounds studied included fructoselysine (FL), the initial glycation product, and the glycoxidation products, N epsilon-(carboxymethyl) lysine (CML) and pentosidine, formed during later Maillard reactions. Collagen-linked fluorescence was also studied. In nondiabetic subjects, glycation of collagen (FL content) increased only 33% between 20 and 85 yr of age. In contrast, CML, pentosidine and fluorescence increased five-fold, correlating strongly with age. In diabetic patients, …

Existence Of High-Order Superlattices In Orientationally Ordered C_{60}, J. E. Fischer, D. E. Luzzi, K. Kniaź, A. R. Mcghie, D. A. Ricketts-Foot, W. R. Romanow, Gavin B. M. Vaughan, Dayin Li, Allan L. Smith, Robert M. Strongin, M. A. Cichy, Laurent Bard, Amos B. Smith Iii

Chemistry Faculty Publications and Presentations

We correlate the presence or absence of high-order modulated structures in solid C₆₀ with the differential scanning calorimetry signature of the orientational ordering transition and other diagnostic data. We have searched for, but not observed, the 2a face-centered cubic structure recently observed in low-temperature electron and single-crystal x-ray diffraction. We conclude that the intrinsic ground state is the previously reported simple cubic structure [space groupPa3¯, a(14 K)=14.06 Å], and that other structures may be stabilized by defects or impurities.