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Articles 30691 - 30720 of 34552

Full-Text Articles in Physical Sciences and Mathematics

The Synthesis Of Amino Acid Derivatives For Peptide Incorporation, Yvette Delahoussaye Apr 1994

The Synthesis Of Amino Acid Derivatives For Peptide Incorporation, Yvette Delahoussaye

Honors Theses

No abstract provided.


Identification Of Aromatic Acids As Microbial Metabolites Of Fossil-Fuel Compounds Present In Aquifer Systems, Daniel Michael Tomczak Apr 1994

Identification Of Aromatic Acids As Microbial Metabolites Of Fossil-Fuel Compounds Present In Aquifer Systems, Daniel Michael Tomczak

Masters Theses

The identification and quantitation of aromatic acids as transformation products present in contaminated aquifer systems was studied from selected sites. These acids are formed as microbial metabolites in the oxidative degradation of aromatic compounds. The microbial activity in the subsurface can be coupled to the oxidation of the aromatic compounds and the reduction of specific inorganic indicators. Inorganic indicators identified from the sample sites include the reduced forms of iron, nitrate, sulfate, and dissolved oxygen.

The highest concentrations of the aromatic acids were found in the plumes of the contaminated sites. These concentrations also correlated with specific changes in concentrations …


Approaches To And Synthesis Of Chalcone Amides, Gregory S. Marczak Apr 1994

Approaches To And Synthesis Of Chalcone Amides, Gregory S. Marczak

Masters Theses

A series of "chalcone" amides have been prepared. These amides are unique in the position of the substituted hydroxy and methoxy functional groups. Early approaches to the synthesis of the amides proved difficult when preparing intermediates from the phenolic substituents. These phenols were then protected to lead to easier formation of the intermediates, and then deprotected to yield the corresponding chalcone amides. The approaches to the preparation of these compounds is presented, along with the physical data used to characterize the chalcone amides.


Diamond Thin Film Sensors For Hypersonic Flow Studies, Bhaskar Kumar Bulusu Apr 1994

Diamond Thin Film Sensors For Hypersonic Flow Studies, Bhaskar Kumar Bulusu

Electrical & Computer Engineering Theses & Dissertations

Conventional metal film sensors can measure flow instabilities of the order of 60 kHz. The turbulence fluctuations in the hypersonic regime are of the order of 200- 400 kHz. To measure these fluctuations, sensors with an enhanced frequency response are required. Therefore, it is required to identify the parameters to enhance the frequency response. These include parameters such as the temperature sensitivity, the resistivity, the thermal conductivity, the diffusivity, specific heat capacity and the geometric size and shape of the film and the substrate. A selection of materials was then carried out to maximize the frequency response. Diamond was identified …


The Synthesis And Characterization Of Poly (1,1'-Divinyl-2,2’-Biimidazole), Timothy S. Evenson Mar 1994

The Synthesis And Characterization Of Poly (1,1'-Divinyl-2,2’-Biimidazole), Timothy S. Evenson

Opportunities for Undergraduate Research Experience Program (OURE)

The monomer 1,1 ,-divinyl-2,2’-biimidazole was prepared using a previously published procedure (1). The new divinyl biimidazole polymer was then synthesized from this monomer. The polymer was characterized by infrared and ultraviolet-visible spectroscopy. Nuclear magnetic resonance confirms the structure of the polymer. Also, gel permeation chromatography was used to determine molecular weight, while differential scanning calorimetry was used to determine the glass transition temperature and crystalline melting point of the polymer.


Macrocyclic Antibiotics As A New Class Of Chiral Selectors For Liquid Chromatography, Christine Bagwill Mar 1994

Macrocyclic Antibiotics As A New Class Of Chiral Selectors For Liquid Chromatography, Christine Bagwill

Opportunities for Undergraduate Research Experience Program (OURE)

In the field of chromatographic separations, the need for new chiral stationary phases is always in demand. Many stationary phases already exist, some of the more popular being cyclodextrin or protein based phases. During this research, a new class of chiral selectors were discovered and evaluated for chiral recognition. Vancomycin, thiostrepton, and rifamycin B all belong to the macrocyclic antibiotic family. Not only can this new class of chiral selectors be used to resolve compounds that cannot be separated on any other column, but it is also more stable and has much greater capacity than protein based columns.


Modified Recycled Glass As An Additive In Coatings Applications, Garth D. Brown Mar 1994

Modified Recycled Glass As An Additive In Coatings Applications, Garth D. Brown

Opportunities for Undergraduate Research Experience Program (OURE)

The feasibility of using chemically modified, finely pulverized recycled glass as an additive in coatings was investigated. The ground glass was added as partial replacement for the conventional pigment titanium dioxide (TiO2). The loss of TiO2 pigment was compensated with an optical brightening agent (OB agents). OB agents can help contribute to a coating’s hiding capacity by absorbing light in the UV range, releasing light of a lower energy in the visible spectrum. Glass supplemented coatings were formulated and common paint tests were performed. The glass changed the optical and physical properties of the coating formulations. The …


Synthesis Evaluation Of New High Performance Polymer Systems Involving Tetrachlorohydroquinone, Jason A. Giles Mar 1994

Synthesis Evaluation Of New High Performance Polymer Systems Involving Tetrachlorohydroquinone, Jason A. Giles

Opportunities for Undergraduate Research Experience Program (OURE)

New high performance transparent polymers are in demand in the aerospace and automotive industries to replace current glass and composite systems. Tetrachlorohydroquinone (TCHQ) was used as the base monomer for various copolymer formulations. Different acid chloride monomers lead to polyester formation with TCHQ. Polycarbonates were formed with triphosgene and diethyl carbonate. This base monomer added rigidity, transparency, and high temperature resistance, however, resulting polymers were brittle and difficult to process. Polymers were characterized by IR and DSC.


Development Of A Recycled Glass Corrosion Inhibitor For Surface Coatings And Concrete Applications, Theresa Pierce Mar 1994

Development Of A Recycled Glass Corrosion Inhibitor For Surface Coatings And Concrete Applications, Theresa Pierce

Opportunities for Undergraduate Research Experience Program (OURE)

This research was performed to study the possibility of attaching a metal corrosion inhibitor to recycled glass powder. Such a material would be useful as a corrosion inhibitor component for metal substrate coatings. The major experiments performed were first to produce a metal corrosion inhibitor (Irgacor 153)/silane coupling agent (3-(chloropropyl)trimethoxysilane) adduct and secondly to attach this corrosion inhibitor/silane adduct onto the surface of glass. To test feasibility, qualitative corrosion tests were performed using steel wool as the corroding metal and a number of product samples.


Electrochemical Enzyme Immunoassay Using Sequential Saturation Technique In A 20-Μl Capillary: Digoxin As A Model Analyte, Noriaki Kaneki, Yan Xu, Anu Kumari, H. Brian Halsall, William R. Heineman, Peter T. Kissinger Mar 1994

Electrochemical Enzyme Immunoassay Using Sequential Saturation Technique In A 20-Μl Capillary: Digoxin As A Model Analyte, Noriaki Kaneki, Yan Xu, Anu Kumari, H. Brian Halsall, William R. Heineman, Peter T. Kissinger

Chemistry Faculty Publications

Capillary enzyme immunoassay with flow-injection analysis for digoxin using the sequential saturation technique has been developed. Glass capillary tubes (10 cm × 0.53 mm i.d.) with immobilized digoxin antibody were used as the immunoassay reactor. The product of enzymatic reaction. 4-aminophenol, was detected amperometrically. The digoxin and the labeled digoxin binding reaction with the immobilized digoxin antibody were completed in 2 and 10 min, respectively. Digoxin was determined in a 20-μl sample with a detection limit of 10 pg ml−1 (200 fg or 260 attomoles) and a 3 orders of magnitude range.


Time Scale For Proton Emission From Highly Excited Projectiles, R. J. Charity, L. G. Sobotka, G. Van Buren, F. A. Tibbals, J. Barreto, D. R. Bowman, M. Chartier, J. Dinius, D. Fox, C. K. Gelbke, D. O. Handzy, W. C. Hsi, P. F. Hua, A. S. Kirov, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, L. Phair, D. G. Sarantites, C. Schwarz, R. T. De Souza, M. B. Tsang, C. Williams Mar 1994

Time Scale For Proton Emission From Highly Excited Projectiles, R. J. Charity, L. G. Sobotka, G. Van Buren, F. A. Tibbals, J. Barreto, D. R. Bowman, M. Chartier, J. Dinius, D. Fox, C. K. Gelbke, D. O. Handzy, W. C. Hsi, P. F. Hua, A. S. Kirov, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, L. Phair, D. G. Sarantites, C. Schwarz, R. T. De Souza, M. B. Tsang, C. Williams

Faculty Publications

Highly fragmented exit channels produced by the decay of excited 24Mg projectiles were detected. The longitudinal velocity spectra of protons and alpha particles from such channels are offset. This offset is consistent with post-breakup Coulomb accelerations from the 197Au target nuclei implying that the protons were emitted within 3 X 10−22 s after the target-projectile separation.


Synthesis And Characterization Of Some Flourine-Containing Lithium Alkyl Sulfonates: Flourinated Sulfonates And Sf5-Containing Sulfonates, Steven A. Ullrich Mar 1994

Synthesis And Characterization Of Some Flourine-Containing Lithium Alkyl Sulfonates: Flourinated Sulfonates And Sf5-Containing Sulfonates, Steven A. Ullrich

Dissertations and Theses

Lithium salts of pentafluorothio alkyl sulfonic acids and perfluoroalkyl disulfonic acids were prepared for testing for possible use as polymer electrolytes. Most of these lithium salts were made from the corresponding sodium, potassium or calcium salts. Aqueous solutions of these salts were passed through polystyrene sulfonate ion exchange resin in the acid form to obtain aqueous solutions of the corresponding acids. The acids were then neutralized with lithium hydroxide using a pH meter. One salt was made by reacting the barium salt of the corresponding acid with lithium sulfate. A sulfonyl fluoride polymer (-0-CH2-C (CH20CF2CF2S02F) H-) n was reacted with …


Charge Transport Properties Of Electrodes Modified By The Spontaneous Adsorption Of Asymmetric Dialkysulfides, Mark Anderson, Minhui Zhang Mar 1994

Charge Transport Properties Of Electrodes Modified By The Spontaneous Adsorption Of Asymmetric Dialkysulfides, Mark Anderson, Minhui Zhang

Mark R. Anderson

No abstract is currently available.


In Situ Structural Characterization Of Modified Surfaces By Polarization Modulation Ftir Reflection Absorption Spectroscopy, Mark Evaniak, Mark Anderson Mar 1994

In Situ Structural Characterization Of Modified Surfaces By Polarization Modulation Ftir Reflection Absorption Spectroscopy, Mark Evaniak, Mark Anderson

Mark R. Anderson

No abstract is currently available.


Effects Of Unpaired Bases On The Conformation And Stability Of 3-Arm Dna Junctions, Min Zhong, Michael S. Rashes, Neocles B. Leontis, Neville R. Kallenbach Mar 1994

Effects Of Unpaired Bases On The Conformation And Stability Of 3-Arm Dna Junctions, Min Zhong, Michael S. Rashes, Neocles B. Leontis, Neville R. Kallenbach

Chemistry Faculty Publications

Three-arm DNA junctions, in which three double helices intersect at a branch, have unique structure and reactivity of bases at and near the branch. Their solution conformation is asymmetric in the presence of Mg2+, while bases at the branch are sensitive to single-strand-specific agents. Following the surprising report that unpaired bases at the branch stabilize three-arm junctions, we have investigated the geometry and thermodynamics of three-arm junctions containing pendant T and A bases. The results are consistent with additional structure formation in junctions containing up to four pendant bases at the branch: relative to the tight junction, the thermal stability …


Competing C–Br And C–C Bond Fission Following 1[N(O),Π∗(C=O)] Excitation In Bromoacetone: Conformation Dependence Of Nonadiabaticity At A Conical Intersection, P. W. Kash, G.C.G. Waschewsky, R. E. Morss, L. J. Butler, Michelle M. Francl Mar 1994

Competing C–Br And C–C Bond Fission Following 1[N(O),Π∗(C=O)] Excitation In Bromoacetone: Conformation Dependence Of Nonadiabaticity At A Conical Intersection, P. W. Kash, G.C.G. Waschewsky, R. E. Morss, L. J. Butler, Michelle M. Francl

Chemistry Faculty Research and Scholarship

These experiments investigate the competition between C-C and C-Br bond fission in bromoacetone excited in the (1)[n(O),pi(*)(C=O)] absorption, elucidating the role of molecular conformation in influencing the probability of adiabatically traversing the conical intersection along the C-C fission reaction coordinate. In the first part of the paper, measurement of the photofragment velocity and angular distributions with a crossed laser-molecular beam time-of-flight technique identifies the primary photofragmentation channels at 308 nm. The time-of-flight spectra evidence two dissociation channels, C-Br fission and fission of one of the two C-C bonds, BrH2C-COCH3. The distribution of relative kinetic energies imparted to the C-Br fission …


A Mössbauer Effect Study Of The Microscopic Magnetic Properties Of Th₂Fe₁₇ And Its Nitride, Th₂Fe₁₇N₂.₆, Gary J. Long, Oran Allan Pringle, Fernande Grandjean, T. H. Jacobs, K. H. Buschow Mar 1994

A Mössbauer Effect Study Of The Microscopic Magnetic Properties Of Th₂Fe₁₇ And Its Nitride, Th₂Fe₁₇N₂.₆, Gary J. Long, Oran Allan Pringle, Fernande Grandjean, T. H. Jacobs, K. H. Buschow

Chemistry Faculty Research & Creative Works

The Mössbauer spectra of Th2Fe17 and Th2Fe17N2.6 have been measured at various temperatures between 85 and 295 K and analyzed with a model that is based on the Wigner-Seitz cell environment of each iron site, the orientation of the magnetization, and the magnetic moments as determined from either neutron-diffraction measurements or band-structure calculations. Upon nitrogenation of Th2Fe17, the 85 K weighted average isomer shift increases from 0.037 to 0.156 mm/s and further the isomer shifts of the four crystallographically distinct sites increase in agreement with the increase observed …


Liver Lesions In Winter Flounder (Pseudopleuronectes Americanus) From Jamaica Bay, New York: Indications Of Environmental Degradation, Thomas P. Augspurger, Roger L. Herman, Jeff S. Hatfield, John T. Tanacredi Ph.D. Mar 1994

Liver Lesions In Winter Flounder (Pseudopleuronectes Americanus) From Jamaica Bay, New York: Indications Of Environmental Degradation, Thomas P. Augspurger, Roger L. Herman, Jeff S. Hatfield, John T. Tanacredi Ph.D.

Faculty Works: CERCOM (1977-2016)

Liver sections of winter flounder (Pseudopleuronectes americanus) collected from Jamaica Bay and Shinnecock Bay, New York, in 1989, were examined microscopically to determine the pervasiveness of liver lesions observed previously in Jamaica Bay winter flounder. Neoplastic lesions were not detected in fish from Jamaica Bay or the Shinnecock Bay reference site. Twenty-two percent of Jamaica Bay winter flounder examined (n=103) had unusual vacuolization of hepatocytes and biliary pre-ductal and ductal cells (referred to hereafter as the vacuolated cell lesion). The lesion, identical to that found in 25% of Jamaica Bay winter flounder examined in 1988, has previously been …


Solubility Studies Of Iron(Iii) Oxides And Hydroxides, Victor L. Menting Feb 1994

Solubility Studies Of Iron(Iii) Oxides And Hydroxides, Victor L. Menting

Dissertations and Theses

The hydrolysis of iron(III) ions in aqueous solution forms a series of soluble hydroxide complexes with associated equilibrium constants. The solubility of iron(III) is controlled by the various soluble hydroxide complexes, and can, in theory, be calculated from the pH and equilibrium constants. Experimental verification of the calculated solubility has proven difficult due to the lack of sensitive analytical techniques and the presence of colloidal ferric hydroxide interferences. Recently, electrochemical methods for the determination of low levels of iron(III) have been developed using adsorptive cathodic stripping voltammetry which relies on the interfacial accumulation of the chelate of iron with Solochrome …


A Memorable Meeting, February 1994, Fathi Habashi Feb 1994

A Memorable Meeting, February 1994, Fathi Habashi

Fathi Habashi

Decision taken at the Steering Committee Meeting of the International Mineral Processing Congress in San Francisco February 1994 to name the IMPC Award.


The Nuclear Hexadecapole Interaction Of Iodine-127 In Cadmium Iodide Measured Using Zero-Field Two Dimensional Nuclear Magnetic Resonance, Ming-Yuan Liao, Gerard S. Harbison Feb 1994

The Nuclear Hexadecapole Interaction Of Iodine-127 In Cadmium Iodide Measured Using Zero-Field Two Dimensional Nuclear Magnetic Resonance, Ming-Yuan Liao, Gerard S. Harbison

Gerard Harbison Publications

Two dimensional nuclear quadrupole correlation spectroscopy has been used to measure simultaneously the two nuclear spin transition frequencies for the iodine resonance of cadmium iodide at zero magnetic field. Because of the layer structure and resultant polymorphism in this substance, conventional zero-field NMR spectra are inhomogeneously broadened by several hundred kHz. However, the 2D spectra obtained by our method are subject only to homogeneous line-width, which for this compound is of the order of 5 kHz. This greatly increased precision allows more accurate evaluation of the nuclear hexadecapole coupling- in cadmium iodide; which we measure as 0.216 ±0.514 kHz (i.e., …


6li And 15n Nuclear Magnetic Resonance Studies Of Mixed Alkali Metal Cation Hexamethyldisilazide Bases, Michael Nichols, Delia Waldmüller, Paul Williard Jan 1994

6li And 15n Nuclear Magnetic Resonance Studies Of Mixed Alkali Metal Cation Hexamethyldisilazide Bases, Michael Nichols, Delia Waldmüller, Paul Williard

Michael A Nichols

No abstract provided.


A Spectroscopic Study Of Nitrogen, Nitrogen/Helium And Fluorobenzenes In A Corona Supersonic Discharge, Jing-Chen Luo Jan 1994

A Spectroscopic Study Of Nitrogen, Nitrogen/Helium And Fluorobenzenes In A Corona Supersonic Discharge, Jing-Chen Luo

Dissertations

No abstract provided.


Synthesis Of Enantioenriched Piperidine-Based, Spirocyclic Analogues Of Af64a And Acetylcholine, Nam Huh Jan 1994

Synthesis Of Enantioenriched Piperidine-Based, Spirocyclic Analogues Of Af64a And Acetylcholine, Nam Huh

Dissertations

No abstract provided.


Chiral Isoparathion Methyl As A Stereospecific Probe Of Phosphorothiolate Mechanism Of Action; Novel Synthetic Approaches Toward Isoquinolone Alkaloids: Pancratistatin Study, Seungmin Ryu Jan 1994

Chiral Isoparathion Methyl As A Stereospecific Probe Of Phosphorothiolate Mechanism Of Action; Novel Synthetic Approaches Toward Isoquinolone Alkaloids: Pancratistatin Study, Seungmin Ryu

Dissertations

No abstract provided.


Development And Functional Properties Of Intramolecular Crosslinked Hemoglobin, Qunyang Zhang Jan 1994

Development And Functional Properties Of Intramolecular Crosslinked Hemoglobin, Qunyang Zhang

Dissertations

No abstract provided.


Monte Carlo Simulation Of Acetonitrile Clusters [Ch3cn] N , N=2–256: Melting Transitions And Even/Odd Character Of Small Clusters (N=2–9), Heat Capacities, Density Profiles, Fractal Dimension, Intracluster Dimerization, And Dipole Orientation, D. Wright, M. Samy El-Shall Jan 1994

Monte Carlo Simulation Of Acetonitrile Clusters [Ch3cn] N , N=2–256: Melting Transitions And Even/Odd Character Of Small Clusters (N=2–9), Heat Capacities, Density Profiles, Fractal Dimension, Intracluster Dimerization, And Dipole Orientation, D. Wright, M. Samy El-Shall

Chemistry Publications

The thermodynamic and structural properties of acetonitrile clusters [CH3CN] N , N=2–15, 20, 30, 60, 128, and 256 have been investigated using Monte Carlo simulation. Interactions in the small clusters (N≤9) are dominated by antiparallel pairing of the molecular dipoles. The simulations reveal rigid ↔ fluid (melting) transitions with a remarkable even–odd alternation in the transition temperatures for the N=2–9 clusters. The higher melting temperatures of the even‐N clusters arise as consequences of the antiparallel paired dipoles which provide favorable electrostatic interactions. Even–odd alternation has also been observed in the configurational energies and …


Highly Reactive Forms Of Zinc And Reagents Thereof, Reuben D. Rieke Jan 1994

Highly Reactive Forms Of Zinc And Reagents Thereof, Reuben D. Rieke

Chemistry Department: Faculty Publications

A novel zerovalent zinc species and an organozinc reagent are disclosed. The zerovalent zinc species is directly produced by reaction of a reducing agent on a zinc salt, preferably Zn(CN)2. The organozinc reagent results from the reaction of the zerovalent zinc species and an organic compound having one or more stable anionic leaving groups. These organozinc reagents include a wide spectrum of functional groups in the organic radical, and are useful in a variety of reactions schemes.


The Chemistry Of Allergies, Henry Daley Jan 1994

The Chemistry Of Allergies, Henry Daley

Bridgewater Review

No abstract provided.


Use Of Pyocin To Select A Haemophilus Ducreyi Variant Defective In Lipooligosaccharide Biosynthesis, A A. Campagnari, R Karalus, M A. Apicella, William Melaugh, A J. Lesse, B W. Gibson Jan 1994

Use Of Pyocin To Select A Haemophilus Ducreyi Variant Defective In Lipooligosaccharide Biosynthesis, A A. Campagnari, R Karalus, M A. Apicella, William Melaugh, A J. Lesse, B W. Gibson

Chemistry Faculty Publications

Haemophilus ducreyi, a cause of genital ulcer disease in developing countries, appears to facilitate the heterosexual transmission of the human immunodeficiency virus in Africa. Despite an increase in studies of this gram-negative human pathogen, little is known about the pathogenesis of chancroid. Our studies have shown that the lipooligosaccharides (LOS) of H. ducreyi may play an important role in ulcer formation. Monoclonal antibody and mass spectrometric analyses identified a terminal trisaccharide present on H. ducreyi LOS that is immunochemically similar to human paragloboside. This epitope is present on the LOS of Neisseria gonorrhoeae, and it may be the site of …