Materials Literature
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Abstract The thermooxidative degradation of poly(oxymethylene) copolymer (CPOM‐Y) powder was studied in air in 150°C. The effect of the sequence distribution of degraded poly(oxymethylene) (POM) samples on the thermal decomposition behavior was investigated with 1 H‐NMR and gas chromatography/mass spectrometry. The re…
Ultrastructural study of cell-cell connections in the outer mantle epithelium (OME) on high-pressure-frozen specimens revealed zonula adherens, septate junctions and gap junctions in Anodonta cygnea. In order to evaluate the permeability of the paracellular pathway, the OME was incubated under gradients of lanthanum a…
Abstract The multiscale morphology of rigid poly(vinyl chloride) (PVC) formulations (in the nanometre to the micrometre range) was investigated by high resolution scanning electron microscopy, ultra‐small‐, small‐ and wide‐angle X‐ray scattering, as a function of thermo‐mechanical history. It has been shown that the h…
Abstract Functional polymers are used as additives in the formulation of fuels either for their detergency properties or for retaining cold weather operability. Examples of recent research work aimed at a better understanding of the physico‐chemical phenomena involved and at the design and synthesis of new polymers ar…
A series of N-methylated polyarylurea oligomers have been reduced with potassium metal in HMPA. These reductions result in the transient formation of arylurea anion radicals, which undergo reductive elimination of the urea linkages. The aryl moieties appear in the products as the anion radicals of oligoaryl systems. T…
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…