Materials Literature
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We have studied relaxation in the Coulomb glass from a nonequilibrium state arising due to an abrupt change of the electron density. Our results are of relevance to some recent experiments on doped and amorphous semiconductors using metal-oxide-semiconductor field-effect transistor geometry, in which the relaxation of…
Protein crystallography is becoming a popular technique that is routinely used to access structural information. At one end of the process, sample preparation is now facilitated by commercially available crystallization kits. At the other end, structure determination has been made easier by automated software. Data co…
Finite element numerical simulations have been carried out to demonstrate that by the dispersing of a small amount of exfoliated muscovite mica platelets in a solid polymer one can considerably reduce and even match the thermal expansion coefficients of metal and polymer components of hybrid polymer-metal structures.…
The effect of Er3+ concentration on the Er3+ : 4I13/2 → 4I15/2 emission in tellurite glasses has been investigated. The full width at half-maximum increased with the increasing concentration of Er2O3 in tellurite glasses. The effect of local structure of Er3+ ions and related spectroscopic changes are taken into accou…
Abstract Nanocomposite materials are prepared by drying a mixed colloidal suspension of film‐forming latex and silica. The dispersion state of the silica particles in the dry film controls the properties. We describe, with the help of some examples, how the colloidal stability of the particles in the mixed suspension…
We report on the giant magnetoresistance (GMR) of multiwall carbon nanotubes with ultrasmall diameters. In particular, we consider the effect of the interwall interactions and the lead/nanotube coupling. Comparative studies have been performed to show that in the case when all walls are well coupled to the electrodes,…
We report on nonequilibrium molecular-dynamics simulations of shear-induced melting for a two-dimensional crystal under either constant shear or constant stress. In both cases, dissipation of heat was accounted for by a configurational thermostat which does not exert any constraint on the flow profile. Results from bo…
Single crystals of strontium cobaltate, SrCoO(3-x), have been grown by the floating-zone method in an oxygen flow. The compound crystallizes with the cubic perovskite structure, with Pm-3m symmetry, as determined by X-ray diffraction. Refinement of the O-atom site occupancy yields the chemical composition SrCoO(2.64)…
The control of Terfenol-D’s operational elastic modulus offers opportunities for novel devices and applications capitalizing on real-time changes in material stiffness. This work describes the development and testing of a Terfenol-D transducer employed as a wide-band variable frequency mechanical resonator. The design…
Methyl parathion hydrolase (MPH) from Pseudomonas sp. WBC-3, an enzyme that catalyzes the degradation of methyl parathion (O,O-dimethyl O-p-nitrophenyl phosphorothioate; MP), has been purified and crystallized by the hanging-drop vapour-diffusion method. The crystals were grown at 291 K using a precipitant solution co…
Abstract Adsorption of bovine serum albumin (BSA) onto positively charged core‐shell latex particles with a polystyrene core and a rich poly( N ‐isopropylacrylamide) (NIPAM)) shell layer was investigated as a function of pH, ionic strength and temperature. Adsorption of BSA protein onto such cationic and thermosensiti…
The Mycobacterium tuberculosis rmlC gene encodes dTDP-4-keto-6-deoxyglucose epimerase, the third enzyme in the M. tuberculosis dTDP-L-rhamnose pathway which is essential for mycobacterial cell-wall synthesis. Because it is structurally unique, highly substrate-specific and does not require a cofactor, RmlC is consider…
The ordering of the anionic sublattice at the coexisting high orientational disorder of the cationic sublattice produces spontaneous polarization in imidazolium tetrafluoroborate $[{\mathrm{C}}_{3}{\mathrm{N}}_{2}{\mathrm{H}}_{5}{]}^{+}[{\mathrm{BF}}_{4}{]}^{\ensuremath{-}}.$ This ferroelectric crystal exhibits the Cu…
The crystal structure of an osmotically inducible protein (OsmC) from Escherichia coli has been determined at 2.4 A resolution. OsmC is a representative protein of the OsmC sequence family, which is composed of three sequence subfamilies. The structure of OsmC provides a view of a salt-shock-induced protein. Two ident…
Divergent evolution of enzyme function is commonly explained by a gene duplication event followed by mutational changes that allow the protein encoded by the copy to acquire a new function. An alternate hypothesis is that this process is facilitated when the progenitor enzyme acquires a second function while maintaini…
An Fe(II) ion at an α-cation exchange position of ferrierite, (Fe) α, was taken as a model for the active site in nitrous oxide decomposition and in the selective oxidation of phenol with nitrous oxide. The oxygen that is deposited via the decomposition of N 2 O is commonly referred to as α-oxygen, (O) α . Comparison…
Polystyerene (PS) nanocomposite foams were prepared using CO 2 supercritical fluid (SCF) as a solvent and blowing agent. PS was first in situ polymerized with 0, 1, and 3% Montmorillonite-Layered Silicate (MLS) mixtures, which were then compression-molded into thin laminates. The laminates were foamed in a batch proce…
We recently introduced a new technique for semiconductor nanoparticle research that involves simultaneous single molecule spectroscopy (SMS) and controllable oxidation/reduction in an electronic device. This paper shows that the new technique, denoted by fluorescence-voltage single molecule spectroscopy (F−V/SMS), is…
Politicizing Science provide a valuable insight into the competing interests of science and policymakers, says Ian Gibson.Karl Popper, probably the leading 20 th century philosopher of science, famously divided science into two steps: the formation of a hypothesis followed by its testing.But what happens when science…
Insulation performance of extruded polystyrene (XPS) foams expanded with various halogenated blowing agents including HFC-134a or HCFC-142b was measured over time. Residual blowing agents were measured after aging up to 26 years. The diffusive transport properties of the blowing agents can be determined through the ma…