Materials Literature
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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…
Isothermal phase diagrams for semicrystalline poly(ethylene- co -vinyl alcohol) (EVAL) using two nonsolvents (water and 2-propanol) serving as a cosolvent system have been determined. The locations of the liquid−liquid demixing and the crystallization-induced gelation in the phase diagrams at 60 °C were identified. At…
Alkanethiolate-coated gold nanocrystals have been laser desorbed from a solid film, ionized, and analyzed by time-of-flight mass spectrometry. A previously unresolved distribution of peaks is observed and the number of gold and sulfur atoms associated with each feature can be assigned. Alkyl chains are not evident in…
The structures and energies of B+13, observed experimentally to be an unusually abundant species among cationic boron clusters, have been studied systematically with B3LYP/6–31G* density functional theory. The most thermodynamically stable B+12 and B+13 clusters are confirmed to have planar or quasiplanar rather than…