Materials Literature
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Nonisothermal melt crystallization kinetics of PEDEKmK linked by meta-phenyl and biphenyl was investigated by differential scanning calorimetry (DSC). A convenient and reasonable kinetic approach was used to describe the nonisothermal melt crystallization behavior, and its applicability was verified when the modified…
The position operator (defined within Schroedinger representation as usual) becomes meaningless when the usual Born-von Karman periodic boundary conditions are adopted: this fact is at the root of the polarization problem. I show how to define the position expectation value by means of rather peculiar many-body (multi…
A nonlinear kinetic exclusion model is used to study osmosis and pressure driven flows through nearly single file pores such as antibiotic channels, aquaporins, zeolites and nanotubules. Two possible maxima in the steady state flux as a function of pore-solvent affinity are found. For small driving forces, the linear…
Carbon nanotubes can be functionalized by oxidation of HNO 3 or H 2 SO 4 −HNO 3 . The latter shows a higher capability in producing a high density of surface functional groups. These groups can act as specific nucleation sites for a well-dispersed deposition of Pt clusters on the surface of carbon nanotubes. These mod…
We have synthesized two classes of polyureas with mono- and bisazoaromatic groups in their main chains via reactions between isophorone diisocyanate and the corresponding diamines. Holographic gratings were fabricated on azoaromatic polyurea films prepared by spin-coating from solutions. The effect of high glass trans…
Polysulfonates with reactive pendant chloromethyl groups were synthesized by polyadditions of bisepoxides with disulfonyl chlorides. The polyaddition of bisphenol A diglycidyl ether (BPGE) with m-benzene disulfonyl chloride (m-BDSC) occurred in anisole without any catalyst at 130°C for 24 h. However, polymer with high…
Diacetylene-containing polyimides have been prepared by the oxidative coupling of new diethynyl diimide monomers. Condensation of various ethynyl-terminated amines with either 4,4‘-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) or pyromellitic dianhydride (PMDA) provided the monomers. Processability was enhance…
Ablation characteristics of silicone insulation were examined in an induced air combustion chamber and by thermogravimetric analysis. The rate of ablation increased with the combustion pressure. Although the flame temperature was less effective in increasing the ablation rate, the ablation rate below 1160 K was much s…
Aliphatic diols and dicarboxylic acids condense in hydrophobic solvents to form polyesters at 25–75°C when the solutions interface with an acidic hydrophilic phase. Certain aliphatic ω-hydroxy acids behave similarly. Rigorous removal of the by-produced water by distillation is unnecessary and examples are cited where…
Activity of a cellulosomal endoglucanase (endoglucanase E; EGE) from Clostridium thermocellum against two crystalline forms of cellulose was enhanced by combination with the cellulosome integrating protein (CipA), but CipA did not enhance EGE activity against amorphous cellulose, even though it was able to bind to it.…
A general high-yield synthetic route to the hexacoordinate silicon porphyrin dichloride complexes trans -(Por)SiCl 2 {Por = the dianions of octaethylporphyrin (OEP), tetraphenylporphyrin (TPP), and tetrakis( p -(trifluoromethyl)phenyl)porphyrin (TTFP)} is reported. Reacting (Por)SiCl 2 with SbF 3 and AgOTf produces th…
Conserved residues of the proteolytic domain of Escherichia coli protease Lon, putative members of the classic catalytic triad (H665, H667, D676, and D743) were identified by comparison of amino acid sequences of Lon proteases. Mutant enzymes containing substitutions D676N, D743N, H665Y, and H667Y were obtained by sit…
Homo- and copolymerizations of butadiene (BD) and styrene (St) with rare-earth metal catalysts, including the most active neodymium (Nd)-based catalysts, have been examined, and the cis-1,4 polymerization mechanism was investigated by the diad analysis of copolymers. Polymerization activity of BD was markedly affected…
We have synthesized two classes of polyureas with mono- and bisazoaromatic groups in their main chains via reactions between isophorone diisocyanate and the corresponding diamines. Holographic gratings were fabricated on azoaromatic polyurea films prepared by spin-coating from solutions. The effect of high glass trans…
ADVERTISEMENT RETURN TO ISSUENew Concepts in Bioc...New Concepts in BiochemistryNEXTAmyloid Fibrils May Be Assembled from β-Helical Protofibrils†N. D. Lazo and Donald T. DowningView Author Information The Marshall Research Laboratories, Department of Dermatology, University of Iowa College of Medicine, Iowa City, Iowa…
The surfaces of ozone-pretreated polycarbonate films were subjected to further modification by thermally induced graft copolymerization with acrylic acid (AAc), sodium salt of styrene sulfonic acid (NaSS), N,N-dimethylacrylamide (DMAA), N,N-(dimethylamino)ethyl methacrylate (DMAEMA) and 3-dimethyl(methacryloyl ethyl)-…
To elucidate hydroxyapatite-protein interaction, mutant human lysozymes in which the surface charge was modified by site-directed mutagenesis were used. Five mutant human lysozymes (K1A, K13A, K33A, R10A, R14A) were expressed in yeast. The chromatographic behavior of these lysozymes was studied with a HPLC hydroxyapat…
Surface modification of ozone-pretreated low-density polyethylene (LDPE) films were carried out via a novel technique of UV-induced graft copolymerization with acrylamide (AAm), Na salt of styrenesulfonic acid (NaSS), 3-dimethyl(methacryloylethyl)ammonium propanesulfonate (DMAPS), acrylic acid (AAc), N, N -dimethylacr…
Following gamma irradiation in air which causes bond scission and yields large concentrations of peroxy radicals, maximum oxidation and an increase in crystallinity occurs on the surface of ultrahigh molecular weight polyethylene. Here, bimolecular reactions of peroxy radicals generate carbonyls, mostly ketones. On th…
The adsorption of trichloroethene, C2HCl3, on clay mineral surfaces in the presence of water has been modeled as an example describing a general program that uses molecular dynamics simulations to study the sorption of organic materials at the clay mineral/aqueous solution interface. Surfaces of the clay minerals kaol…