Materials Literature
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Subunit-hybrid enzymes of mutant tetrameric L-lactate dehydrogenases from Bifidobacterium longum were studied in an examination of the mechanism of allosteric activation by fructose 1,6-bisphosphate. We earlier developed an in vivo method for subunit hybridization in Escherichia coli and the hybrids formed were a mixt…
Abstract Microcellular polyurethane foams are generated through phase separation, which is induced by reaction‐induced crosslinking or by a pressure quench. The phase separation conditions are shown to impact the microstructure of the foams. Pore growth will occur through two mechanisms: diffusion of CO 2 from polymer…
The solubility of phenacetin was determined at five temperatures in solvent mixtures of aprotic-amphiprotic mixtures of dioxane and water. Enthalpy-entropy compensation analysis is used to study the effect of changing polarity of the medium on the solute. The apparent heats of solution and free energies of solution ar…
We report a simple technique for fabricating a layer of isolated Si quantum dots on SiO2 glass substrates. This technique uses conventional low-pressure chemical-vapor deposition for an extremely short deposition time in the early stage of poly-Si film growth. The layer after a deposition time of 60 s has isolated Si…
Constant‐load creep‐rupture tests were performed on single Si‐C‐O fibers (Nicalon). Test environments included pure carbon monoxide (CO), pure argon gas, and a mixture of CO and argon gas with a CO partial pressure of 40 kPa. Fibers were tested at temperatures of 1200°‐1400°C and at nominal applied stresses of 0.15–0.…
We have measured the thermopower ($S$) of hole-doped LaMn${\mathrm{O}}_{3}$ systems in order to see its dependence on the ${\mathrm{Mn}}^{4+}$ content as well as to investigate other crucial factors that determine $S$. We have carried out hole doping (creation of ${\mathrm{Mn}}^{4+}$ by two distinct means, namely, by…
The stability of the so-called “gyroid” phase, of $$Ia\bar 3d$$ symmetry, observed for lyotropic liquid crystals and block copolymers is accounted for using the Landau-Brazovskii theory of weak crystallization. In the mean field approximation, the $$Ia\bar 3d$$ phase is stable between the lamellar and hexagonal phases…
The internal conversion and intramolecular vibrational relaxation processes of nitro-tri-tert-butylphthalocyanine, tetra-phenylporphyrin (TPP), and tetra-tert-butylphthalocyanine (BuPc) in chloroform solution were investigated with an ultrafast time-resolved fluorescence depletion method. A regular fluorescence deplet…
A rise in thermal denaturation temperature has been utilized as an indication of stabilization of collagen-containing materials such as pericardial tissue and porcine heart-valve leaflets following treatment with glutaraldehyde, Denacol, or other chemical agents. In contrast, stabilization of bovine pericardial tissue…
Localized adsorption of hard (noninteracting) spheroidal particles on homogeneous interfaces was analyzed theoretically. In contrast to previous studies concentrated on flat (side on) adsorption in the present approach an unoriented (quasi-three-dimensional) adsorption of prolate and oblate spheroids was considered. B…
RATIONALE AND OBJECTIVES: The relative stability and selectivity of magnetic resonance (MR) imaging contrast agents were compared with in vitro transmetallation and ligand competition reactions. MATERIALS AND METHODS: A gadolinium (Gd)-DTPA-BIGA, Gd-DTPA-BMA, Gd-DTPA, or Gd-HP-DO3A solution was mixed with an equimolar…
The optical performance of interference filters depends on systematic and statistical variations of the thicknesses and indices of refraction of the layers that occur during production and use. Assuming that their distributions are known, the expected performance can be optimized as a function of the nominal layer thi…
Other| October 01, 1996 Neutron powder diffraction study of hydrogarnet to 9.0 GPa George A. Lager; George A. Lager University of Louisville, Department of Geography and Geosciences, Louisville, KY, United States Search for other works by this author on: GSW Google Scholar Robert B. Von Dreele Robert B. Von Dreele Los…
Abstract The mechanisms of intramolecular dynamics in transition metal hydride complexes are surveyed in this review. The NMR data for a number of fluxional hydrides are interpreted in terms of principal and secondary topological changes of the coordinated ligands. The principal ligand motions can be further categoriz…
The piezoelectric properties of SrBi4Ti4O15 and Bi4Ti2.95Nb0.04O12 have been compared as a function of applied ac stress. Evidence of domain-wall motion was observed in Bi4Ti2.95Nb0.04O12 but not in SrBi4Ti4O15. Examination of SrBi4Ti4O15 using transmission electron microscopy revealed that the material had undergone…
An elastic‐plastic analysis of damage in ceramic coatings on metal substrates from contacts with spherical indenters is made using finite element modeling. Computations are carried out specifically for plasma‐sprayed alumina:titania on a soft steel. The algorithm assumes an elastic sphere with frictionless contact on…
The effects of transesterification on the miscibility of poly(ethylene terephthalate)/poly(ethylene 2,6-naphthalate) were studied. Blends were obtained by solution precipitation at room temperature to avoid transesterification during blend preparation. The physical blends and transesterified products were analyzed by…
The polyaromatics are an important group of industrial polymers. For the highest performance applications the polyaryletherketones and polyarylethersulphones have proved very effective and have been successfully commercialised. Both polymer types, but mainly polyetheretherketone (Victrex PEEK), have been subjected to…
The proton conducting Ba3Ca1.18Nb1.82O9−δ complex oxide electrolyte is shown to have proton conductivity σH > 10−2 S/cm with transport number tH > 0.98 at 600 °C. Concentration cell measurements up to 800 °C with different gases show no sign of residual electronic conduction with a total ionic transport number, tH + t…
Interatomic potentials of the embedded-atom type have been developed for H in metals. The potentials are constructed through a fitting procedure involving the thermodynamic heat of solution of H in the various metals and the volume expansion of the host lattice upon the dissolution of H. The potentials have been devel…