Chemistry Commons^™

Interobserver Agreement In The Diagnosis Of Stroke Type, Cynthia R. Gross, David Shinar, Jay P. Mohr, Daniel B. Hier, Louis R. Caplan, Thomas R. Price, Philip A. Wolf, Carlos S. Kase, Irene G. Fishman, Sandra Calingo, Selma C. Kunitz

Chemistry Faculty Research & Creative Works

Interobserver Agreement is Essential to the Reliability of Clinical Data from Cooperative Studies and Provides the Foundation for Applying Research Results to Clinical Practice. in the Stroke Data Bank, a Large Cooperative Study of Stroke, We Sought to Establish the Reliability of a Key Aspect of Stroke Diagnosis: The Mechanism of Stroke. Seventeen Patients Were Evaluated by Six Neurologists. Interobserver Agreement Was Measured When Diagnosis Was based on Patient History and Neurologic Examination Only, as Well as When It Was based on Results of a Completed Workup, Including a Computed Tomographic Scan. Initial Clinical Impressions, based Solely on History and …

A Non-Aqueous Lamellar Liquid Crystal With An Ionic Surfactant-Long Chain Alcohol Combination, Stig Friberg, Paul Liang, Yuh Chirn Liang, Bettye Greene, Ron Van Gilder

Chemistry Faculty Research & Creative Works

A non-aqueous lamellar liquid crystal of sodium dodecyl sulfate, decanol and glycerol was prepared and compared with its aqueous counterpart. The results show that the stability of the liquid crystal with glycerol is critically dependent on the surfactant/alcohol ratio, whereas the liquid cry. The interlayer spacing was smaller for the glycerol system than for the water system at finite amount of solvent, but the value extrapolated to zero so. © 1986.

Microemulsions With High Water Solubilizing Capacity At High Hydrocarbon Levels And Very Low Surfactant Concentrations, Raymond L. Venable, Kay Lynn Elders, Jiafu Fang

Chemistry Faculty Research & Creative Works

Phase diagrams have been determined showing the extent of the inverse micellar or microemulsion region for systems consisting of water-surfactant-cosurfactant or water-surfactant-hydrocarbon cosurfactant mixture with three surfactants and four cosurfactants. The surfactants are sodium dodecyl sulfate, sodium laurate, and tetradecyltrimethylammonium bromide while the cosurfactants are pentanol, hexanol, pentylamine, and hexylamine. Hexylamine is found to be a very effective cosurfactant giving rise to very good water solubilizing capacity at extremely low surfactant concentrations and very low cosurfactant levels at rather high initial hydrocarbon levels. © 1986.

Stability Of Hydrophobic Foams, Stig Friberg, Irena Blute, Hironobu Kunieda, Per Stenius

Chemistry Faculty Research & Creative Works

The stability of foams was determined in two-phase regions containing an isotropic hydrocarbon solution and a lamellar liquid crystal. The lamellar liquid crystal showed surface activity with regard to the hydrocarbon solution. This was interpreted as due to the higher frequency of methyl groups at the surface of the liquid-crystalline state compared to the liquid state. The weaker intermolecular forces from the methyl groups were assumed to result in a lower surface tension of the liquid crystal in comparison to the liquid. This hypothesis was tested by the use of a low surface tension hydrocarbon, isooctane. No foam stability was …

Foams From A Three-Phase Emulsion, Hironobu Kunieda, Stig Friberg

Chemistry Faculty Research & Creative Works

Foam stability was related to phase behavior in a foamed three-phase region consisting of an aqueous solution (L1), an alcohol solution (L2) and lamellar liquid-crystalline (LC) phases in the C8H17SO3Na/C8H17OH/H2O system. The state of the system before foaming was LC/L2 + LC/L1 or L1 + L2/LC type emulsions up to a high octanol/water ratio of 77/23. In L2 + LC/L1 emulsion, the LC droplets exist separately from the alcohol droplets in an aqueous continuous medium. The viscosity of the system was enhanced with an increase in the content of dispersed phases, i.e. alcohol and/or liquid crystal phases contributing to the …

Surfactant Association Structures And The Stability Of Emulsions And Foams, Stig Friberg, Concepcion Solans

Chemistry Faculty Research & Creative Works

Traditional surfactants in combination with water and a more hydrophobic amphiphile, such as an alcohol or a carboxylic acid, present a rich variety of colloidal association structures, both micelles and lyotropic liquid crystals. The presence of such association structures has a pronounced influence on the stability of macro dispersed systems such as emulsions and foams. A few examples of such an influence are discussed. © 1986, American Chemical Society. All rights reserved.

Amphiphilic Association Structures And Some Aspects Of Foam Stability, Jia-Hwa Fang

Doctoral Dissertations

"This investigation was performed in order to study two interesting and important problems in foams.

Foam separation was studied in the model system of water - sodium octylsulfonate - decanol. The efficiency of foam separation as a function of surfactant concentration and decanol content were measured. The results were related to the association structures of amphiphiles in aqueous systems.

Foam polymerization was conducted in the amphiphilic system containing water, polymerizable surfactant and oleyl alcohol. Liquid foams were produced in one three - phase region. The location and optical pattern of liquid crystals on the foam surface were observed by photomicroscope …

Dynamic Structure Of N-Hexadecane Solubilized In A Nonionic Surfactant Bilayer Measured By Deuteron Magnetic Resonance, Anthony J.I. Ward, Stig Friberg, David W. Larsen, Shankar B. Rananavare

Chemistry Faculty Research & Creative Works

A 2H NMR study was made of the order parameters of n-hexadecane molecules solubilized up to 55% (w/w) in a lyotropic lamellar liquid crystal of tetra ethylene glycol n-dodecyl ether and water for a range of compositions of varying water and hydrocarbon content. The NMR data supported a model with only a small amount of penetration of the hydrocarbon between the amphiphilic molecules and a rapid exchange on the 2H NMR time scale between the penetrated segments and the nonpenetrating molecules which latter are essentially isotropic. © 1985, American Chemical Society. All rights reserved.

Plasma Polymerization Investigated By The Substrate Temperature Dependence., H. Yasuda, Cheng Wang

Chemistry Faculty Research & Creative Works

In the reported experiments, plasma polymerization of tetrafluoroethylene (TFE), perfluoro-2-butyl-tetrahydrofuran (PFBTHF), ethylene, and styrene were investigated in various combinations of monomer flow rates and discharge wattages for the substrate temperature range of minus 50 to 80 degree C. The polymer deposition rates can be generally expressed by k//o equals Ae** minus **b**t, where k//o is the specific deposition rate given by k//o equals (deposition rate)/(mass flow rate of monomer), A is the preexponential factor representing the extrapolated value of k//o at zero absolute temperature, and b is the temperature-dependence coefficient. It was found that the value of b is not …

Racial Differences In The Distribution Of Posterior Circulation Occlusive Disease, Philip B. Gorelick, Louis R. Caplan, Daniel B. Hier, Dushyant Patel, Patricia Langenberg, Michael S. Pessin, Jose Biller, David Kornack

Chemistry Faculty Research & Creative Works

We Compared Clinical and Arteriographic Features in 27 White and 24 Black Patients with Symptomatic Posterior Circulation Occlusive Disease. the Degree of Arterial Stenosis Was Measured Independently by Two Examiners at 12 Sites within the Vertebrobasilar Territory. Racial Comparisons Were Made based Upon the Distribution of Extra- and Intracranial Occlusive Lesions and Symptomatic Sites of the Lesions. White Patients Had Significantly More Angina Pectoris, More Lesions of the Origin of the Left Vertebral Artery and More High-Grade Lesions of the Extracranial Vertebral Arteries. Black Patients Had Significantly Higher Mean Diastolic Blood Pressure, More Diabetes Mellitus, More Lesions of the Distal …

Removal Of Colloidal Silica In Simulated Seawater By A Dynamic Multi-Short-Circuited Galvanic Cell, Jan E. Osterholm, Paul W. Kramer, Hlrotsugu K. Yasuda

Chemistry Faculty Research & Creative Works

A dynamic multi-short-circuited galvanic cell (MSCGC) with Pt-AI electrodes has been used to study the removal of colloidal silica from seawater as a pretreatment step for the desalination of seawater by use of reverse osmosis. The rate of silica removal is observed to be affected by the flow rate of the solution through the cell and the dissolved oxygen content of the solution as well as by the nature of the aluminum electrode surface and the number of contact points (short circuits) between the aluminum and platinum. The total silica content is reduced by 95 % by use of this …

Chapter 3 Coatings And Surface Modification Using Low Pressure Non-Equilibrium Plasmas, Harold F. Winters, Robert P.H. Chang, C. J. Mogab, John Evans, John A. Thornton, Hirotsugu Yasuda

Chemistry Faculty Research & Creative Works

No abstract provided.

Interobserver Variability In The Assessment Of Neurologic History And Examination In The Stroke Data Bank, David Shinar, Cynthia R. Gross, Jay P. Mohr, Louis R. Caplan, Thomas R. Price, Philip A. Wolf, Daniel B. Hier, Carlos S. Kase, Irene G. Fishman, Christine L. Wolf, Selma C. Kunitz

Chemistry Faculty Research & Creative Works

Interobserver Reliability in Obtaining Neurologic Histories and Examinations Was Investigated among Neurologists Collaborating in the Stroke Data Bank (SDB). Seventeen In-Hospital Stroke Patients Were Examined by Six Neurologists Experienced in Stroke over the Course of Three Days. Patients Were Examined Twice a Day for Two Successive Days, with Each Patient Seen by Four Different Neurologists. Data Were Recorded on SDB Forms, According to Definitions and Procedures Established for the SDB. Percent Agreement and Κ Coefficients Were Calculated to Assess the Levels of Agreement for Each Item. Important Differences in Levels of Agreement Were Found among Items on Both Neurologic History …

Evaluation Of Plasma Polymers Of Silanes As Adhesion Promoters For Organic Paint, Y. Matsuda, H. Yasuda

Chemistry Faculty Research & Creative Works

Plasma-polymerized coatings were prepared in a bell-jar-type reactor equipped with a magnetron system behind parallel aluminum electrodes using an a.c. source of frequency 10 kHz. Tetramethoxysilane, dimethyldimethoxysilane and hexamethyldisilane were used as monomers. Alkyd paint was coated on titanium plates onto which plasma polymer films had been deposited, to investigate the characteristics of the plasma-deposited films as adhesion promoters. The relationship between the adhesion strength for the paint and the conditions for the plasma polymerization was studied. The properties of the plasma polymers are dependent on the conditions of plasma polymerization manifested by two domains, namely the energy-deficient and the …

Preparation Of Gas Separation Membranes By Plasma Polymerization With Fluoro Compounds, H. Nomura, P. W. Kramer, H. Yasuda

Chemistry Faculty Research & Creative Works

Plasma polymerization coatings were applied for the preparation of gas separation membranes. Mainly fluoro compounds were used as coating materials. The membranes showed good separation characteristics with high flux for gaseous systems. The plasma polymerization composite parameter given by W/FM plays an important role in obtaining excellent separation characteristics. The correlation between the conversion rate DR/FM, where DR is the deposition rate of plasma polymer, and W/FM is useful to consider the plasma polymer character under the different plasma polymerization conditions (discharge power W and monomer flow rate F). The proper conditions for membrane preparation lie in the intermediate region …

Magnetic Phase Diagram And Spin Glass Behavior Of Fe₁₋ₓmnₓcl₂·2h₂O, Gary C. Defotis, Christoph Pohl, Spencer A. Pugh, Ekkehard Sinn

Chemistry Faculty Research & Creative Works

The magnetic phase diagram of Fe_1-xMn_xCl₂·2H₂O has been determined. A tetracritical point appears to be present at x ≊ 0.74 and T≊2.8 K. The upper paramagnetic-antiferromagnetic phase boundaries exhibit an unusually rapid descent, and the mixed ordered region below the tetracritical point is quite small. Moreover, regions exhibiting spin glass character also occur in the diagram. The unusually complex behavior is presumably due to the unique constitution of this system: A mixture of two antiferromagnets with different periodicities, competing orthogonal spin anisotropics, competing ferromagnetic and antiferromagnetic near neighbor intrachain exchange interactions, and …

Preparation And Characterization Of Composite Hollow Fiber Reverse Osmosis Membranes By Plasma Polymerization. 2. Reproducibility Of The Plasma Polymerization Process And Durability Of The Resulting Coated Membrane, Y. Matsuzawa, H. Yasuda

Chemistry Faculty Research & Creative Works

The reproducibility of the plasma polymerization process was examined in a semicontinuous coating of hollow fibers, 6 fibers in lengths of approximately 12-15 m, by evaluating the performance of reverse osmosis membranes. The uniformity of the coating along the length of hollow fibers, as well as the reproducibility of the process, was found to be satisfactory when electrodes were conditioned in the actual conditions of plasma polymerization to be employed and plasma polymerization conditions were carefully controlled. The durability of the coated hollow fibers was then investigated in the following test media: hot water, low pH, high pH, and 0.1% …

Preparation And Characterization Of Composite Hollow Fiber Reverse Osmosis Membranes By Plasma Polymerization. 1. Design Of Plasma Reactor And Operational Parameters, P. J. Heffernan, K. Yanaglhara, Y. Matsuzawa, E. E. Hennecke, E. W. Hellmuth, H. Yasuda

Chemistry Faculty Research & Creative Works

Composite hollow fiber reverse osmosis membranes were prepared by depositing a thin layer (10-50 nm) of plasma polymers on hollow fibers with porous walls (made of polysulfone). The coating was carried out in a semicontinuous manner with six strands of substrate fibers. Operational parameters which influence reverse osmosis characteristics of composite membranes were investigated. © 1984, American Chemical Society. All rights reserved.

Magnetic And Crystallographic Structure Of Y₆Mn₂₃D₂₃, K. A. Hardman-Rhyne, James J. Rhyne, E. Prince, Cyrus E. Crowder, William Joseph James

Chemistry Faculty Research & Creative Works

The magnetic behavior of Y6Mn23 is dramatically altered upon hydrogenation (or deuteration). In this study it has been found, by means of high-resolution powder diffraction and Rietveld refinement techniques, that the crystallographic structure is distorted from face-centered cubic (Fm3m) at 295 K to a primitive tetragonal structure at 4 K in which deuterium atoms are atomically ordered. Y6Mn23 is a ferromagnetic compound with Tc=486 K, and bulk magnetization of 13.2 Bf.u. (formula unit). After deuteration of Y6Mn23 to the composition Y6Mn23D23, low-temperature scattering data (T<180 K) show that the b and f2 sites in the Fm3m structure are antiferromagnetic and the d and f1 sites have no spontaneous magnetic moment. © 1984 The American Physical Society.

A Lamellar Liquid Crystal As An In Situ Surface Balance. I. The Conformation Of 5- (And 6-)Carboxy-4-Hexyl-2-Cyclohexene-1-Yl Octanoic Acid And Its Monosoap, Tony Flaim, Stig Friberg

Chemistry Faculty Research & Creative Works

The interfacial conformation of a dicarboxylic acid, 5- (and 6-)carboxy-4-hexyl-2-cyclohexene-1-yl octanoic acid, and its monosodium soap was determined from the change of liquid crystal dimensions after introduction of the diacid compounds. The results showed that both functional groups of the Mono soap form were present at the interface and that increased water content of the liquid crystal matrix had little effect on the conformation of the Mono soap. On the other hand, the results indicated the conformation of the diacid as such to depend on the water content of the matrix. At low water content, the diacid form was in …

Order Parameters Of Hydrocarbons Solubilized In A Lamellar Liquid Crystal, Anthony J.I. Ward, Stig Friberg, David W. Larsen, Shankar B. Rananavare

Chemistry Faculty Research & Creative Works

A preliminary study of the 2H NMR spectrum of n-hexadecane-d34 solubilized in the lamellar phase of tetra ethylene glycol n-dodecyl ether has been made as a function of solubilization content. Complex spectra comprising eight overlapping powder spectra were observed, which showed a complex oil concentration dependence. These spectra were unusually rich in detail and indicate a considerably higher degree of complexity than has earlier been reported for solubilized hydrocarbons. The derived order profile was found to be different from that normally found for amphiphiles in lamellar environments. A tentative model involving some penetration of solubilize molecules between the host amphiphiles …

Single Compound Forming A Lyotropic Liquid Crystal At Room Temperature, Stig Friberg, Paul Liang, Frances E. Lockwood, Maher Tadros

Chemistry Faculty Research & Creative Works

The compound triethanolammonium oleate forms a lamellar liquid crystal at room temperature. The basis for the lyotropic mesomorphism is the fact that part of the triethanolammonium oleate has changed to triethanolamine and oleic acid. These two compounds serve as solvents in the liquid crystalline structure. © 1984 American Chemical Society.

Molecular Motion And Phases In An Equimolar Phosphatidylcholine/Ethylene Glycol System, David W. Larsen, Shankar B. Rananavare, Frank E. Stary, Magda Elnokaly, Stig Friberg

Chemistry Faculty Research & Creative Works

An equimolar mixture of phosphatidylcholine and ethylene glycol was studied by pulsed proton NMR at temperatures between 100 and 430 K. Relaxation times T1, T1ρ, and T1D, and second moments, M2, were measured. The system is lamellar liquid crystalline at room temperature, but at least four phases are present within the temperature range studied. Phase transitions were confirmed by DSC. Activation barriers were estimated for methyl reorientation, choline group motion, and chain motion. Models to describe the various motions and the role of spin diffusion are discussed. The relationship of the parameters for the present system to those for the …

Solubilization Of Calcium Dodecyl Sulfate In A Micellar Solution And In Lamellar Liquid Crystal, Stig Friberg, David W. Osborne

Chemistry Faculty Research & Creative Works

Calcium dodecyl sulfate (CDS) was solubilized in the aqueous micellar solution of sodium dodecyl sulfate and in the lamellar liquid crystal obtained from water, sodium dodecyl sulfate and decanal. The solubilization of CDS in the micellar solution was strongly increased with the concentration of sodium dodecyl sulfate while the maximum amount of CDS solubilized in the liquid crystal remained similar. The solubilization in the micellar solution was gradually increased with the alcohol content with a sudden reduction to zero at the decanol/sodium-dodecyl-sulfate ratio marking the end of the micellar region with no calcium soap being present. The dependence of the …

Lyotropic Liquid Crystals From Lecithin, Water, And Polyethylene Glycol, Magda El Nokaly, Stig Friberg, David W. Larsen

Chemistry Faculty Research & Creative Works

Lyotropic liquid crystals with lecithin as the amphiphile and with water/polyethylene glycol (PEG) solutions as the solvent were prepared with polyethylene glycol/water ratios from 182 to 0. The liquid crystals were lamellar and the interlayer spacing was independent of the solvent content for water/PEG ratios ≤1 but increased strongly with the water/PEG ratio. Higher ratios gave increased interlayer spacing with solvent content similar to the variation for liquid crystals with water as solvent but the absolute values of the spacing were higher. © 1984 Academic Press, Inc. All rights reserved.

Composition Of Regenerated Cell Walls Of Reverting Aureobasidium Pullulans Protoplasts, D. R. Quigley, Donald J. Siehr

Chemistry Faculty Research & Creative Works

Protoplasts of Aureobasidium pullulans, formed by treating normal blastospores with polysaccharide-hydrolizing enzymes, synthesized glycans when incubated in shallow culture. The polysaccharides formed a loose, thick coating on the cells. The glycans that were formed are similar to the glycans in normal cell walls; however, they lack the branching that is normally found. This result is consistent with the findings of others who have studied the cell wall composition of reverting yeast protoplasts.

Alignment Of A Nonaqueous Lyotropic Liquid Crystalline Phase With Lecithin, David W. Larsen, Shankar B. Rananavare, Stig Friberg

Chemistry Faculty Research & Creative Works

No abstract provided.

Aphasia After Left Thalamic Infarction, Philip B. Gorelick, Daniel B. Hier, Louis Benevento, Susan Levitt, Walter Tan

Chemistry Faculty Research & Creative Works

We Examined a 70-Year-Old Woman Who Became Aphasic after a Left Thalamic Infarction. Computed Tomographic Scan Showed Injury that Was Largely Limited to the Ventral Anterior and Rostral Ventral Lateral Thalamic Nuclei. Speech Was Characterized by Reduced Voice Volume, Impaired Auditory and Reading Comprehension, Perseverations, Intermittent Use of Jargon, Fluctuations in the Ability to Perform Confrontation Naming, Extraneous Intrusions, Verbal Paraphasia, Intact Repetition Skills, and Fluent Speech that Was Laconic But Grammatically Correct. We Propose that the Deficits after Left Thalamic Injury Can Be Grouped into the Following Four Large Clusters: Extrapyramidal Deficits (Decreased or Fading Voice Volume), Deficits in …

Plasma Polymerization Of Tetramethyldisiloxane By A Magnetron Glow Discharge, Ashok K. Sharma, H. Yasuda

Chemistry Faculty Research & Creative Works

Plasma polymerization of tetramethyldisiloxane by a magnetron glow discharge was studied. The glow discharge was created between parallel electrodes with a 10 kHz electric power source with a superimposed magnetic field using permanent bar magnets. Polymers were deposited onto moving substrates placed on the surface of a rotating disc located in between the electrodes. The deposition rates were determined with a quartz crystal thickness monitor placed on the plane of the rotating disc and just outside the edge of the disc. The current-voltage relationship observed for plasma polymerization of the monomer depends on the monomer feed rate and the conditioning …

Structural Changes Induced By Addition Of A Hydrocarbon To Water/Amphiphile Mixtures, H. Sagitani, Stig Friberg

Chemistry Faculty Research & Creative Works

The phase conditions in a system of water, hexadecane, sodium dodecyl sulphate, and di-ethylene glycol dodecyl ether showed the W/O microemulsions to be obtained first after destabilization of a liquid crystalline phase by addition of the hexadecane. The original lamellar liquid crystalline phase was moved towards higher surfactant/cosurfactant ratios and a new phase with inverse amphiphile cylinders in a hexagonal packing appeared. © 1983 Steinkopff.