Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 12 of 12
Full-Text Articles in Physical Sciences and Mathematics
Mössbauer-Effect, Magnetic, And Neutron-Diffraction Study Of Nafep₂O₇, R. C. Mercader, L. Terminiello, Gary J. Long, D. G. Reichel, K. Dickhaus, R. Zysler, R. Sanchez, M. Tovar
Mössbauer-Effect, Magnetic, And Neutron-Diffraction Study Of Nafep₂O₇, R. C. Mercader, L. Terminiello, Gary J. Long, D. G. Reichel, K. Dickhaus, R. Zysler, R. Sanchez, M. Tovar
Chemistry Faculty Research & Creative Works
Neutron-diffraction, magnetic-susceptibility, specific-heat, and Mössbauer-effect studies of NaFeP2O7 reveal that it is a normal Heisenberg isotropic three-dimensional antiferromagnetic material with a Néel temperature of 29.0 K. NaFeP2O7 has the monoclinic P21/c magnetic space group, which is the same as the nuclear crystallographic space group. The easy axis of magnetization lies in the monoclinic ac plane at an angle of 21.0° from the c axis. The specific-heat measurements reveal a λ-type anomaly at 28.7(2) K. A molecular-field model analysis indicates that the intrasublattice magnetic exchange coupling Jaa=Jbb=-0.37 cm-1, whereas …
Polar-Liquid, Derivatized Cyclodextrin Stationary Phases For The Capillary Gas Chromatography Separation Of Enantiomers, Daniel W. Armstrong, Weiyong Li, Chau Dung Chang, Josef Pitha
Polar-Liquid, Derivatized Cyclodextrin Stationary Phases For The Capillary Gas Chromatography Separation Of Enantiomers, Daniel W. Armstrong, Weiyong Li, Chau Dung Chang, Josef Pitha
Chemistry Faculty Research & Creative Works
A new class of hydrophilic, relatively polar liquid, cyclodextrin (CD) derivatives have been used as highly selective chiral stationary phases (CSPs) for capillary gas chromatography (GC). Several possible requirements for liquidity In CD derivatives are discussed. O-(S)-2-Hydroxypropyl derivatives of α-, β-, and γ-cyclodextrlns were synthesized, exclusively characterized, permethylated, and evaluated for enantloselectlvity. Seventy pairs of enantiomers were resolved. They represent a wide variety of structural types and classes of compounds including chlral alkyl amines, amino alcohols, epoxides, pyrans, furans, sugars, dlols, esters, ketones, bicyclic compounds, alcohols, and so on. Many of these compounds were not aromatic and cannot be resolved …
Reversing Enantioselectivity In Capillary Gas Chromatography With Polar And Nonpolar Cyclodextrin Derivative Phases, Daniel W. Armstrong, Weiyong Li, Josef Pitha
Reversing Enantioselectivity In Capillary Gas Chromatography With Polar And Nonpolar Cyclodextrin Derivative Phases, Daniel W. Armstrong, Weiyong Li, Josef Pitha
Chemistry Faculty Research & Creative Works
No abstract provided.
Caudate Infarcts, Louis R. Caplan, Edward Feldmann, Jeremy D. Schmahmann, Carlos S. Kase, Phillip B. Gorelick, Daniel B. Hier, Cathy Helgason, George Baquis, John P. Greenberg
Caudate Infarcts, Louis R. Caplan, Edward Feldmann, Jeremy D. Schmahmann, Carlos S. Kase, Phillip B. Gorelick, Daniel B. Hier, Cathy Helgason, George Baquis, John P. Greenberg
Chemistry Faculty Research & Creative Works
Eighteen Patients Had Caudate Nucleus Infarcts (10 Left-Sided; 8 Right-Sided). Infarcts Extended into the Anterior Limb of the Internal Capsule in 9 Patients, and Also the Anterior Putamen in 5 Patients. Thirteen Patients Had Motor Signs, Most Often a Slight Transient Hemiparesis. Dysarthria Was Common (11 Patients). Cognitive and Behavioral Abnormalities Were Frequent, and Included Abulia (10 Patients), Agitation and Hyperactivity (7 Patients), Contralateral Neglect (3 Patients, All Right Caudate), and Language Abnormalities (2 Patients, Both Left Caudate). the Majority of Patients Had Risk Factors for Penetrating Artery Disease. Branch Occlusion of Heubner's Artery, or Perforators from the Proximal Anterior …
Plasma Surface Treatment On Nylon Fabrics By Fluorocarbon Compounds, Yu Iriyama, Takeshi Yasuda, D. L. Cho, H. Yasuda
Plasma Surface Treatment On Nylon Fabrics By Fluorocarbon Compounds, Yu Iriyama, Takeshi Yasuda, D. L. Cho, H. Yasuda
Chemistry Faculty Research & Creative Works
Nylon fabrics were treated by low temperature fluorocarbon plasmas. All of the fluorocarbon plasmas applied altered the surface of nylon fabrics to be hydrophobic and water‐repellent. The durability of hydrophobicity and water repellency was examined by measurements of the water contact angle, the water droplet rolling‐off angle, and the breakthrough water pressure after plasma‐treated fabrics were washed. It was found that the structure of starting fluorocarbon and the plasma energy input were important factors in the durability. After washing, surface dynamics were investigated on different drying conditions. It was found that chemical composition and water repellency were dependent on drying …
Derivatized Cyclodextrins For Normal-Phase Liquid Chromatographic Separation Of Enantiorners, Daniel W. Armstrong, San Chun Chang, Apryll M. Stalcup, Martha L. Hilton, Jo Dee Duncan, James R. Faulkner
Derivatized Cyclodextrins For Normal-Phase Liquid Chromatographic Separation Of Enantiorners, Daniel W. Armstrong, San Chun Chang, Apryll M. Stalcup, Martha L. Hilton, Jo Dee Duncan, James R. Faulkner
Chemistry Faculty Research & Creative Works
Several different derivatized β-cyclodextrins were synthesized and used as chiral stationary phases in normal-phase liquid chromatography. The multiply substituted derivatives were made with acetic anhydride, (R)-and (S)-1-(1-naphthyl) ethyl isocyanate, 2, 6-dimethylphenyl isocyanate, and p-toluoyl chloride. The first successful cyclodextrln-based, normal-phase separation of enantiomers was accomplished on these derivative phases. In contrast to chiral separations on the native β-cyclodextrin stationary phase, the enantiomeric separation mechanism on these new phases is not thought to be dependent on inclusion complexation. The similarities and differences between the derivatized cyclodextrin stationary phases and the cellulosic stationary phases are discussed. © 1990, American Chemical Society. All …
Relevance Of Enantiomeric Separations In Food And Beverage Analyses, Daniel W. Armstrong, Chau Dung Chang, Wei Yong Li
Relevance Of Enantiomeric Separations In Food And Beverage Analyses, Daniel W. Armstrong, Chau Dung Chang, Wei Yong Li
Chemistry Faculty Research & Creative Works
A series of new derivatized cyclodextrins have been developed for use as chiral stationary phases in capillary gas chromatography. As a result, a large number of the enantiomeric components in food and beverage products can be resolved relatively quickly and easily. The study focuses on compounds other than amino acids (e.g., malic acid, lactic acid, tartaric acid, esters, alcohols, lactone flavors or fragrances, and so on). The ability to separate and quantitate enantiomers at low levels should be useful for detecting adulterated products, for evaluating fermentation processes, and for the accurate characterization of enantiomeric flavor components, growth regulators, pesticides, and …
Coatings And Surface Modification By Methane Plasma Polymerization, Chung‐Peng ‐P Ho, H. Yasuda
Coatings And Surface Modification By Methane Plasma Polymerization, Chung‐Peng ‐P Ho, H. Yasuda
Chemistry Faculty Research & Creative Works
Polymers formed from plasma‐polymerized methane were employed to modify the surface properties of silicone rubber membrane. Polymers were evaluated based on the energy input parameter W/FM, where W is the discharge power, F is the monomer flow rate, and M is the molecular weight of the monomer. Dealing with the characteristics of plasma polymerization and the deposited polymer film, the effect of pumping rate on deposition rate and the coating thickness, surface energy, and gas permeabilities of methane‐plasma‐polymer‐coated silicone rubber membrane were investigated in three plasma regions. Because more reactive species are expelled at high pumping rates, the monomer‐deficient region …
Dementia In Stroke Survivors In The Stroke Data Bank Cohort: Prevalence, Incidence, Risk Factors, And Computed Tomographic Findings, Thomas K. Tatemichi, Mary A. Foulkes, J. P. Mohr, Jeffrey R. Hewitt, Daniel B. Hier, Thomas R. Price, Philip A. Wolf
Dementia In Stroke Survivors In The Stroke Data Bank Cohort: Prevalence, Incidence, Risk Factors, And Computed Tomographic Findings, Thomas K. Tatemichi, Mary A. Foulkes, J. P. Mohr, Jeffrey R. Hewitt, Daniel B. Hier, Thomas R. Price, Philip A. Wolf
Chemistry Faculty Research & Creative Works
We Determined the Prevalence of Dementia in 927 Patients with Acute Ischemic Stroke Aged ≥60 Years in the Stroke Data Bank Cohort based on the Examining Neurologist's Best Judgment Diagnostic Agreement among Examiners Was 68% (K=0.34). of 726 Testable Patients, 116 (16%) Were Demented. Prevalence of Dementia Was Related to Age But Not to Sex, Race, Handedness, Educational Level, or Employment Status Before the Stroke. Previous Stroke and Previous Myocardial Infarction Were Related to Prevalence of Dementia Although Hypertension, Diabetes Mellitus, Atrial Fibrillation, and Previous Use of Antithrombotic Drugs Were Not Prevalence of Dementia Was Most Frequent in Patients with …
A Study Of The Hydration Properties Of Selected Laser Dye Aerosols Including Continuous-Flow Parallel Plate And Alternating-Gradient Thermal Diffusion Cloud Chamber Measurements In The High Supersaturation Regime, Donald E. Hagen, Max B. Trueblood, Darryl J. Alofs
A Study Of The Hydration Properties Of Selected Laser Dye Aerosols Including Continuous-Flow Parallel Plate And Alternating-Gradient Thermal Diffusion Cloud Chamber Measurements In The High Supersaturation Regime, Donald E. Hagen, Max B. Trueblood, Darryl J. Alofs
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The Hydration Behavior of Aerosols made Up of Various Fluorescent Dyes when Exposed to Water Saturation or Supersaturated Conditions Has Been Studied. Critical Supersaturation Spectra Are Reported. the Dyes Are Found to Behave as High Molecular Weight Ionic Compounds that Obey Kohler Theory. their Relevant Kohler Parameters Are Measured. This Study Makes Use of and Compares Results from the Isothermal Hazecontinuous-Flowand Alternating-Gradient Thermal Diffusion Cloud Chambers. the Ability of the Continuous-Flow Thermal Diffusion Chamber to Operate Correctly at High Supersaturations is Shown. © 1990 Elsevier Science Publishing Co., Inc.
Sans From Tetradecylpyridinium Bromide Based Microemulsions, Paul M. Lindemuth, Boualem Hammouda, Raymond L. Venable
Sans From Tetradecylpyridinium Bromide Based Microemulsions, Paul M. Lindemuth, Boualem Hammouda, Raymond L. Venable
Chemistry Faculty Research & Creative Works
Small-angle neutron scattering is used to investigate tetradecyl pyridinium bromide/pentanol/heptane/heavy water microemulsions in the water-in-oil (W/O) microemulsion phase diagram region. The heavy water content is increased while the other components (surfactant, cosurfactant, hydrocarbon) are kept constant. With use of a simple model assuming spherical micelles interacting with a hard-sphere potential (Percus-Yevick model), aggregate sizes and packing fractions have been extracted and found to agree with values determined from the mixing conditions. These experiments clearly show the transition from the single-particle (heavy water + Stern layer droplet) scattering regime at low water concentration to the mixed single/interdroplet scattering regime when the …
Self‐Diffusion Coefficients Of Boc‐Amino Acid Anhydrides Under Conditions Of Solid Phase Peptide Synthesis, Stephen Pickup, Frank D. Blum, Warren T. Ford
Self‐Diffusion Coefficients Of Boc‐Amino Acid Anhydrides Under Conditions Of Solid Phase Peptide Synthesis, Stephen Pickup, Frank D. Blum, Warren T. Ford
Chemistry Faculty Research & Creative Works
No abstract provided.