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Articles 31351 - 31380 of 34554

Full-Text Articles in Physical Sciences and Mathematics

Weed Control On The South Coast., J. H. Moore Jan 1990

Weed Control On The South Coast., J. H. Moore

Experimental Summaries - Plant Research

Trial 90A141

Barley variety tolerance to herbicides.

Location: Gairdner river.

To determine the tolerance of five barley varieties to 19 herbicides and mixtures.

Trial 90AL43

Herbicides for erodium control in serradella.

Location: North Woogenilup.

To determine the efficacy and phytotoxicity of a range of herbicides at varying rates, on erodium in a first year serradella pasture.

Trial 90AL44

Silvergrass control in pasture.

Location: Cheynes Beach Road.

To determine the efficacy of simazine and gramoxone, either tankmixed or individually at varying rates, on silver grass in a clover based pasture.

Trial 90AL45

Pattersons curse control.

To determine which herbicides and at …


Path Integral Study Of The Correlated Electronic States Of Na4–Na6, Randall W. Hall Jan 1990

Path Integral Study Of The Correlated Electronic States Of Na4–Na6, Randall W. Hall

Collected Faculty and Staff Scholarship

Feynman’s path integral formulation of quantum mechanics is used to study the correlated electronic states of Na4–Na6. Two types of simulations are performed: in the first, the nuclei are allowed to move at finite temperature in order to find the most stable geometries. In agreement with previous calculations, we find that planar structures are the most stable and that there is significant vibrational amplitude at finite temperatures, indicating that the Born–Oppenheimer surface is relatively flat. In the second type of simulation, the nuclei are held fixed at symmetric and asymmetric geometries and the correlated electron density is found. Our results …


Positive Residues Involved In The Voltage-Gating Of The Mitochondrial Porin-Channel Are Localized In The External Moiety Of The Pore, Philadelphia University Jan 1990

Positive Residues Involved In The Voltage-Gating Of The Mitochondrial Porin-Channel Are Localized In The External Moiety Of The Pore, Philadelphia University

Philadelphia University, Jordan

No abstract provided.


Coincidence Orientations Of Crystals In Tetragonal Systems, With Applications To Yba2cu3o7, Abha Singh, N. Chandrasekhar, Alexander H. King Jan 1990

Coincidence Orientations Of Crystals In Tetragonal Systems, With Applications To Yba2cu3o7, Abha Singh, N. Chandrasekhar, Alexander H. King

Alexander H. King

We have developed a method for the characterization of coincidence-site lattices (CSL's) in tetragonal or near-tetragonal orthorhombic structures, by suitable modifications to the method of Grimmer & Warrington [Acta Cryst. (1987), A43, 232-243]. We have applied our method to determine coincidence rotations and the associated information appropriate for forming constrained CSL's in the high-To superconductor YBazCu307-n. The unit cell is orthorhombic with lattice parameters a = 3.82, b = 3"89 and c = 11.67 A for the nominal composition. We present tables of coincidence rotation angles, .Z, CSL, DSCL and associated step vectors up to ,~ = 50. We find …


Hyperfine Structure Of The Mnh X 7-Sigma(+) State: A Large Gas-To-Matrix Shift In The Fermi Contact Interaction, Thomas Varberg, R. Field, A. Merer Jan 1990

Hyperfine Structure Of The Mnh X 7-Sigma(+) State: A Large Gas-To-Matrix Shift In The Fermi Contact Interaction, Thomas Varberg, R. Field, A. Merer

Thomas D. Varberg

No abstract provided.


Isoprenylation Is Required For The Processing Of The Lamin A Precursor, Michael Sinensky, L. A. Beck, T. J. Hosick Jan 1990

Isoprenylation Is Required For The Processing Of The Lamin A Precursor, Michael Sinensky, L. A. Beck, T. J. Hosick

Faculty Publications, Biological Sciences

The nuclear lamina proteins, prelamin A, lamin B, and a 70-kD lamina-associated protein, are posttranslationally modified by a metabolite derived from mevalonate. This modification can be inhibited by treatment with (3-R,S)-3-fluoromevalonate, demonstrating that it is isoprenoid in nature. We have examined the association between isoprenoid metabolism and processing of the lamin A precursor in human and hamster cells. Inhibition of 3-hydroxy-3-methylglutaryl coenzyme A reductase by mevinolin (lovastatin) specifically depletes endogenous isoprenoid pools and inhibits the conversion of prelamin A to lamin A. Prelamin A processing is also blocked by mevalonate starvation of Mev-1, a CHO cell line auxotrophic for mevalonate. …


A Course In Laboratory And Stockroom Management, John T. Moore Jan 1990

A Course In Laboratory And Stockroom Management, John T. Moore

Faculty Publications

No abstract provided.


Biological Markers In Lower Jurassic Synrift Lacustrine Black Shales, Hartford Basin, Connecticut, U.S.A., Michael A. Kruge, John F. Hubert, Jay F. Akes, Paul E. Meriney Jan 1990

Biological Markers In Lower Jurassic Synrift Lacustrine Black Shales, Hartford Basin, Connecticut, U.S.A., Michael A. Kruge, John F. Hubert, Jay F. Akes, Paul E. Meriney

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

The East Berlin Formation (Lower Jurassic, Hartford basin, Connecticut, U.S.A.) is distinctive for its six cyclic units of lacustrine black shale and gray mudstone. separated by playa and fluvial redbeds. The black shales arc each about a meter thick and were deposited in subtropical, thermally stratified, oligomictic lakes, the youngest of which (lakes 3 through 6) were large enough to flood most of the basin and attained depths of several tens of meters.

The saturate fractions of solvent extracts of organic-rich black shales from each of the six lakes, collected at fresh roadcuts near East Berlin, arc dominated by extended …


Organic Geochemistry Of A Lower Jurassic Synrift Lacustrine Sequence, Hartford Basin, Connecticut, U.S.A., Michael A. Kruge, John F. Hubert, David F. Bensley, John C. Crelling, R Jay Akes, Paul E. Meriney Jan 1990

Organic Geochemistry Of A Lower Jurassic Synrift Lacustrine Sequence, Hartford Basin, Connecticut, U.S.A., Michael A. Kruge, John F. Hubert, David F. Bensley, John C. Crelling, R Jay Akes, Paul E. Meriney

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Synrift terrestrial strata of the Lower Jurassic East Berlin Formation (Hartford basin, Connecticut, U.S.A.) record cyclical expansion and contraction of major lakes, six of which were deep enough to develop anoxic bottom waters. We have studied one representative lacustrine sequence in detail, sampling a new roadcut near the village of East Berlin. The section examined is 4 m thick, with a gray siltstone at the base, deposited in shallow water, overlain by an organic-rich black shale (deep water), succeeded in turn by another gray siltstone, deposited as the lake waters gradually receded. The upper gray siltstone is chemically distinct from …


Isoprenylation Is Required For The Processing Of The Lamin A Precursor, Michael Sinensky, L. A. Beck, T. J. Hosick Jan 1990

Isoprenylation Is Required For The Processing Of The Lamin A Precursor, Michael Sinensky, L. A. Beck, T. J. Hosick

Michael Sinensky

The nuclear lamina proteins, prelamin A, lamin B, and a 70-kD lamina-associated protein, are posttranslationally modified by a metabolite derived from mevalonate. This modification can be inhibited by treatment with (3-R,S)-3-fluoromevalonate, demonstrating that it is isoprenoid in nature. We have examined the association between isoprenoid metabolism and processing of the lamin A precursor in human and hamster cells. Inhibition of 3-hydroxy-3-methylglutaryl coenzyme A reductase by mevinolin (lovastatin) specifically depletes endogenous isoprenoid pools and inhibits the conversion of prelamin A to lamin A. Prelamin A processing is also blocked by mevalonate starvation of Mev-1, a CHO cell line auxotrophic for mevalonate. …


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 Jan 1990

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.


Imide/Arylene Ether Copolymers, Brian J. Jensen Jan 1990

Imide/Arylene Ether Copolymers, Brian J. Jensen

Theses and Dissertations

Three different series of imide/arylene ether block copolymers were prepared using two different imide blocks and two different arylene ether blocks. Block molecular weights studied were 3110 and 6545 g/mole for each block and all four combinations possible were prepared in each series. Also, several segmented copolymers were prepared by forming the imide segment and the copolymer in the presence of the pre-formed arylene ether block.

Two amine-terminated poly(arylene ether) blocks (ATPAE) were prepared by reacting 1,3-bis(4-fluorobenzoyl)benzene with either 2,2-bis(4-hydroxyphenyl)propane (BPA) or 9,9-bis(4-hydroxyphenyl)fluorene (BPF) and 4-aminophenol. Two anhydride-terminated poly(amic acid) blocks were prepared by reacting 4,4'-oxydianiline (ODA) or 1,3-bis(4-aminophenoxy-4’- benzoyl)benzene …


Evaluation Of A Remote Sensor For Mobile Source Co Emissions, Donald H. Stedman, Gary A. Bishop Jan 1990

Evaluation Of A Remote Sensor For Mobile Source Co Emissions, Donald H. Stedman, Gary A. Bishop

Fuel Efficiency Automobile Test Publications

No abstract provided.


Automobile Testing In The Toronto Area, Donald H. Stedman, Gary A. Bishop Jan 1990

Automobile Testing In The Toronto Area, Donald H. Stedman, Gary A. Bishop

Fuel Efficiency Automobile Test Publications

No abstract provided.


Telomere Structure In Euplotes Crassus: Characterization Of Dna-Protein Interactions And Isolation Of A Telomere-Binding Protein, Carolyn M. Price Jan 1990

Telomere Structure In Euplotes Crassus: Characterization Of Dna-Protein Interactions And Isolation Of A Telomere-Binding Protein, Carolyn M. Price

Chemistry Department: Faculty Publications

The nucleoprotein structure of telomeres from Euplotes crassus was studied by using nuclease and chemical footprinting. The macronuclear telomeres were found to exist as DNA-protein complexes that are resistant to micrococcal nuclease digestion. Each complex encompassed 85 to 130 base pairs of macronuclear DNA and appeared to consist of two structural domains that are characterized by dissimilar DNA-protein interactions. Dimethyl sulfate footprinting demonstrated that very sequence-specific and salt-stable interactions occur in the most terminal region of each complex. DNase I footprinting indicated that DNA in the region 30 to 120 base-pairs from the 5' end lies on a protein surface; …


Barley Development Experiment., K. J. Young Jan 1990

Barley Development Experiment., K. J. Young

Experimental Summaries - Plant Research

Trial 88ES1

Mechanisms controlling development in barley.

Location: Melijinup Field Station.

A range of barley varieties have been assessed for their level of adaptation to a range of sowing dates across the cereal growing region of W.A. This study aims to determine the mechanisms controlling development in cultivars which represent the range of development responses available. The relative importance of photoperiod and vernalisation response and inherent earliness will be determined for each variety.


Coatings And Surface Modification By Methane Plasma Polymerization, Chung‐Peng ‐P Ho, H. Yasuda Jan 1990

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 …


Plasma Surface Treatment On Nylon Fabrics By Fluorocarbon Compounds, Yu Iriyama, Takeshi Yasuda, D. L. Cho, H. Yasuda Jan 1990

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 Jan 1990

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 …


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 Jan 1990

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 …


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 Jan 1990

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 …


Sans From Tetradecylpyridinium Bromide Based Microemulsions, Paul M. Lindemuth, Boualem Hammouda, Raymond L. Venable Jan 1990

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 Jan 1990

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.


Relevance Of Enantiomeric Separations In Food And Beverage Analyses, Daniel W. Armstrong, Chau Dung Chang, Wei Yong Li Jan 1990

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 …


Study Of Deposition Methods For Silicon Powder, Kamesh V. Gadepally, Kevin B. Tennal, Roger M. Hawk, Al Robles, James A. Gribel Jan 1990

Study Of Deposition Methods For Silicon Powder, Kamesh V. Gadepally, Kevin B. Tennal, Roger M. Hawk, Al Robles, James A. Gribel

Journal of the Arkansas Academy of Science

Silicon powder tends to agglomerate at normal atmospheric conditions and is, hence, difficult to aerosolize. Several methods of aerosolizing silicon powder and finally depositing it on various substrates were investigated. This paper presents the investigated methods of aerosolization. The electrostatic spray coating used in dry paint application was found to be the most suitable. The general merits of this method and its use for silicon powder deposition to form films are discussed.


Comparison Of The Molecular Structures Of Monovalent Cation Salets Of N,N-Dimethyldithiocarbamate. Novel Synthesis And Crystal Structure Of (Phi4)(S2cn(Ch3)2)2h2o, Mark Draganjac, David Minick, Elizabeth M. Holt Jan 1990

Comparison Of The Molecular Structures Of Monovalent Cation Salets Of N,N-Dimethyldithiocarbamate. Novel Synthesis And Crystal Structure Of (Phi4)(S2cn(Ch3)2)2h2o, Mark Draganjac, David Minick, Elizabeth M. Holt

Journal of the Arkansas Academy of Science

Crystals of the tetraphenylphosphonium N,N-dimethyldithiocarbamate dihydrate (C₂₇H₃₀NO₂PS₂; F.W. = 495.6) are monoclinic; P2₁/n; a = 13.349(6), b = 20,968(6), c = 9.800(4) Å, β = 109.01(3)°; Z = 4; V = 2593.4(16) Å^3; Dₓ = 1.269 gcm- 3 . Data were collected at ambient temperature using MoKα radiation (λ = 0.71069 Å).F(000) = 1048, linear absorption coefficient, n = 2.80 cm- 1. The structure was solved by direct methods and subsequently refined by full matrix least squares techniques. Final R value = 0.064 for 1 61 0 reflections and 298 varied parameters. Due to the nature of the cation, interactions …


The Enhancement Of The Incineration Of Model Volatile Organic Solvents By The Use Of Hydrogen Peroxide As A Novel Oxidative Homogeneous Catalyst, Douglas James Tomlin Jan 1990

The Enhancement Of The Incineration Of Model Volatile Organic Solvents By The Use Of Hydrogen Peroxide As A Novel Oxidative Homogeneous Catalyst, Douglas James Tomlin

Retrospective Theses and Dissertations

No abstract provided.


Improving The Analytical Recovery Of Radiostrontium From Environmental Samples, Luz Selenia Acosta Jan 1990

Improving The Analytical Recovery Of Radiostrontium From Environmental Samples, Luz Selenia Acosta

Retrospective Theses and Dissertations

No abstract provided.


Evaluation Of Persian And Balansa Clovers., R. Snowball Jan 1990

Evaluation Of Persian And Balansa Clovers., R. Snowball

Experimental Summaries - Plant Research

Trial 89MC6, 89HA3, 89W10

Evaluation of Persian and Balansa clovers.

Evaluate a range of Trifolium species including a selection of Persian and Balansa clovers.


Rheology Of Aqueous Suspensions Of Polystyrene Latex Stabilized By Grafted Poly(Ethylene Oxide), Harry J. Ploehn, J. W. Goodwin Jan 1990

Rheology Of Aqueous Suspensions Of Polystyrene Latex Stabilized By Grafted Poly(Ethylene Oxide), Harry J. Ploehn, J. W. Goodwin

Faculty Publications

A water-soluble carbodiimide has been used to end-graft aminated poly (ethylene oxide)(PEO) chemically onto colloidal polystyrene particles. Two particle sizes (115 and 347 nm diameter) and two PEO molecular weights (112 000 and 615 000 g mol–1) were combined to give suspensions with four different ratios of polymer layer thickness to particle radius. Electrophoresis demonstrated that the PEO was grafted, not just adsorbed. Dynamic light scattering showed that the adsorbed and grafted layers had similar structures and that non-ionic surfactant perturbed the PEO configurations. Steady shear and oscillatory rheometry indicated that long-ranged polymeric forces between particles governed the …