Materials Literature
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The X-ray crystal structure has revealed two similar alpha/beta domains of aspartate racemase (AspR) from Pyrococcus horikoshii OT3, and identified a pseudo mirror-symmetric distribution of the residues around its active site [Liu et al. (2002) J. Mol. Biol. 319, 479-489]. Structural homology and functional similarity…
A simple triacetylide complex of chromium(III) is synthesized for use as a potential precursor to metal-dicarbide clusters. Reaction of Me(3)SiCCLi with [(Me(3)tacn)Cr(CF(3)SO(3))(3)] (Me(3)tacn = N,N',N"-trimethyl-1,4,7-triazacyclononane) in THF generates [(Me(3)tacn)Cr(CCSiMe(3))(3)], which subsequently reacts with…
In this study, the evolution of the flow stress for grain sizes ranging from about 16 to 2 μm under shear deformation was simulated using two-dimensional discrete dislocation dynamics. The analyses were confined to a single slip system and to the collective behaviour of a large number of edge dislocations, modelled as…
A multi-pyrazolyl cyclotriphosphazene containing polymerizable group N(3)P(3)(3,5-Me(2)Pz)(5)(O-C(6)H(4)-p-C(6)H(4)-p-CH=CH(2)) (2) has been prepared from the corresponding chloro derivative N(3)P(3)Cl(5)(O-C(6)H(4)-p-C(6)H(4)-p-CH=CH(2)) (1). The X-ray structures of 1 and 2 have been determined. Compound 2 undergoes…
Polyelectrolyte multilayers adsorbed on colloidal particles were investigated by means of small-angle neutron scattering at contrast matching conditions. Pronounced periodic oscillations related to the latex particle size and to the layer thickness were observed. The scattering data could be well described by assuming…
The elastic dynamics of $\mathrm{AgNa}({\mathrm{NO}}_{2}{)}_{2}$ crystals around the proper ferroelectric phase transition at ${T}_{C}=38\ifmmode^\circ\else\textdegree\fi{}C$ was investigated by ultrasonic $(f=10\mathrm{MHz})$ and dynamic mechanical analysis (f=0.6-50 Hz) techniques. The system represents a unique exa…
Abstract The kinetics involved in the thermal degradation of polyacrylamide under nitrogen atmosphere were studied by using consecutive reactions of a kinetic model to dynamic thermogravimetric data. The model proposed correlates the thermograms obtained at thermogravimetric and differential thermogravimetric data wit…
Abstract Many problems with odor and taste in food packaging can be traced to degradation of the packaging materials during processing. From this starting point, the degradation of polyethylene in a commercial extrusion coating process was studied by analyzing degradation products present in smoke sampled at the extru…
NiL4X2·xH2O compounds [L=1-(2-carbamoylethyl)-4-methylimidazole (C4MIm), 1-(2-carbamoylethyl)benzimidazole (CBIm) or 1-(2-carbamoylethyl)-5,6-dimethylbenzimidazole (CMMBIm)] have been prepared and characterised and the effect of different axial ligands, X, on the magnetic properties of the complexes has been examined.…
The biostability of a series of polypyrrole (PPy)-coated polyester fabrics was investigated in an in vitro model. PPy-coated sample fabrics were incubated in saline at 37 degrees C for 1 and 2 weeks. After each period of incubation, the surface electrical resistivity of the sample fabrics was measured to monitor the c…
The structural, magnetic, and electrical properties of ${\mathrm{Y}}_{0.5}{\mathrm{Sr}}_{0.5}{\mathrm{MnO}}_{3}$ and ${\mathrm{Y}}_{0.4}{\mathrm{Sr}}_{0.6}{\mathrm{MnO}}_{3}$ have been measured. Magnetic data [e.g., the frequency dependence of ac susceptibility, the zero-field-cooled and field-cooled magnetization beh…
L-Threonine acetaldehyde-lyase (threonine aldolase, TA) is a pyridoxal-5'-phosphate-dependent (PLP) enzyme that catalyzes conversion of L-threonine or L-allo-threonine to glycine and acetaldehyde in a secondary glycine biosynthetic pathway. X-ray structures of Thermatoga maritima TA have been determined as the apo-enz…
Chitosan and chitosan-amino acid derivatives were explored to engineer poly(D,L-lactic acid) (PDL-LA) as an extracellular matrix-like surface to promote cell adhesion and growth. Four kinds of chitosan-amino acid derivatives were prepared to mimic the carbohydrate moieties of cell matrix glycoprotein. The chitosan-ami…
Abstract Silica particles were treated by silane coupling agents to study the effects of surface chemistry of silica particles on the secondary structure formed by silica particles in styrene–butadiene rubber (SBR). The relation between the size of secondary structure and tensile properties of silica‐filled SBR vulcan…
In this paper we study the magnetocaloric effect in the rare-earth cobalt intermetallic compounds $R{\mathrm{Co}}_{2}(R=\mathrm{Dy},\mathrm{Ho},\mathrm{Er}).$ We use a theoretical model, in which the localized spins of the rare-earth ions are immersed into an effective subsystem of the itinerant electrons. In the calc…
Rhenium(IV) sulfide, ReS(2), has been prepared with nanotubular morphology by carbon nanotube templating. A multiwall carbon nanotube material was impregnated with solutions of NH(4)ReO(4) or ReCl(5), followed by drying and sulfidation with H(2)S at 1000 degrees C. The composite material synthesized was characterized…
We investigate the microscopic mechanisms responsible for microdomain alignment in block copolymer solutions exposed to an electric field. Using time-resolved synchrotron small-angle x-ray scattering, we reveal two distinct processes, i.e., grain boundary migration and rotation of entire grains, as the two dominant mi…
The time dependent response of the magnetic and transport properties of Fe-doped phase separated (PS) manganite La(0.5)Ca(0.5)MnO3 is reported. The nontrivial coexistence of ferromagnetic (FM) and non-FM regions induces a slow dynamics which leads to time relaxation and cooling rate dependence within the PS regime. Th…
Using in situ small-angle X-ray scattering, the electric field induced orientation in a block copolymer having a cylindrical microdomain morphology was investigated. Studies were performed with the copolymer in different initial states. Beginning with a disordered copolymer, composition fluctuations are oriented by th…
Many transition metal compounds show saturation of the resistivity at high temperatures, T, while the alkali-doped fullerenes and the high-Tc cuprates are usually considered to show no saturation. We present a model of transition metal compounds, showing saturation, and a model of alkali-doped fullerenes, showing no s…