Materials Literature
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This paper describes for the first time the synthesis of surface-grafted AB-block copolypeptides, consisting of poly( γ -benzyl l -glutamate) (PBLG) as the A-block and poly( γ -methyl l -glutamate) (PMLG) as the B-block. Immobilized primary amine groups of ( γ -aminopropyl)triethoxysilane (APS) on silicon wafers initi…
Copper(II), zinc(II), and nickel(II) complexes with tridentate imino nitroxyl diradicals, [CuCl(bisimpy)(MeOH)](PF(6)) (1), [ZnCl(2)(bisimpy)] (2), and [NiCl(bisimpy)(H(2)O)(2)]Cl x 2H(2)O (3) (bisimpy = 2,6-bis(1'-oxyl-4',4',5',5'-tetramethyl-4',5'-dihydro-1'H-imidazol-2'-yl)pyridine), were prepared, and their magnet…
Glutamate 47 is conserved in 1-aminocyclopropane-1-carboxylate (ACC) synthases and is positioned near the sulfonium pole of (S,S)-S-adenosyl-L-methionine (SAM) in the modeled pyridoxal phosphate quinonoid complex with SAM. E47Q and E47D constructs of ACC synthase were made to investigate a putative ionic interaction b…
Optical properties of a series of finite sized hydrogenated carbon nanotubes with the smallest diameter of 4 A are studied systematically. Their absorption spectra are calculated with the localized-density-matrix method. The semiempirical MNDO parametric method 3 (PM3) Hamiltonian is employed. The finite optical gaps…
The ring-opening polymerization of N -carboxyanhydrides (NCA) of γ -benzyl l -glutamate and γ-methyl l -glutamate from ( γ -aminopropyl)triethoxysilane (APS) pretreated substrates such as silicon wafers and quartz slides was investigated. FT-IR transmission spectroscopy, circular dichroism measurements, and UV/vis spe…
Two binuclear metal-radical complexes, formed by the reaction of M(hfac)(2) x 2H(2)O (M = Mn or Ni; hfac = hexafluoroacetylacetonate) with the 1,5-dimethyl-3-(4,6-dimethylpyrimidin-2-yl)-6-oxoverdazyl radical (3), were synthesized. The binuclear Mn complex 5 (i.e., 3[Mn(hfac)(2)](2)) crystallizes in the monoclinic spa…
The organic−inorganic hybrid materials obtained by the sol−gel route constitute a new class of solids prepared directly from a molecular precursor in mild conditions. These materials are better described as kinetically controlled solids instead of thermodynamically unstable materials. The reproducibility is observed o…
We report on transport properties of polycrystalline ${\mathrm{Na}}_{8}{\mathrm{Si}}_{46}$ in the temperature range 10 to 300 K. The compound is a type I clathrate with Na incorporated into polyhedra formed by framework Si atoms. Seebeck coefficient and resistivity measurements indicate metallic behavior. The thermal…
BACKGROUND: Early graft failure after the use of less satisfactory autologous grafts (30% of all vein grafts) is caused primarily by the following problems: (1) suitable autologous transplants are limited; (2) biotechnology has not yet been able to produce reliable graft substitutes that are legally and ethically appr…
A convenient synthesis of aliphatic polyesters by the distannoxane-catalyzed polycondensation of aliphatic dicarboxylic acids and aliphatic diols in solvents under azeotropic conditions was developed. To determine the optimum conditions for polycondensation of succinic acid with 1,4-butandiol, the effect of various ty…
Over the past few years a growing number of scientists have dedicated their attention to the synthesis of mesostructured aluminophosphates following the concept of supramolecular structure direction. Their research has produced a large variety of synthetic approaches and yielded materials with various structural prope…
Abstract Composite polyglycidylmethacrylate [poly(GMA)] spherical microparticles capable of responding to magnetic fields were prepared by dispersion polymerization of GMA in the presence of iron oxides. The polymerization reaction was carried out in aqueous alcoholic media (methanol, ethanol, propan‐1‐ol, and butan‐1…
A new dendron with peripheral long alkyl chains and containing five C(60) units in the branching shell has been prepared and attached to a Fréchet-type dendron functionalized with ethylene glycol chains. The peripheral substitution of the resulting globular dendrimer with hydrophobic chains on one hemisphere and hydro…
The electronic structure, stability, electron-phonon coupling, and superconductivity of the nonoxide perovskite ${\mathrm{MgCNi}}_{3}$ are studied using density functional calculations. The band structure is dominated by a Ni d derived density of states peak just below the Fermi energy, which leads to a moderate Stone…
Several synthetic pathways of mesostructured porous silica using nonionic surfactants or copolymers have been reported since the discovery of this new family of materials. We developed a process, which we call a two-step synthesis, that allows us to synthesize MSU-X mesoporous silica, with very good reproducibility an…
The selective catalytic reduction of NO x (NO + NO 2 ) at low temperature with ammonia has been investigated with natural manganese ore, pure manganese dioxide, and manganese dioxide supported alumina. The catalysts showed high activities for NO x reduction with NH 3 in the presence of O 2 at temperatures below 250 °C…
In this paper the kinetics of the pozzolanic reaction between lime (calcium hydroxide) and sugar cane straw ash with 20 and 30% of clay burned at 800 and 1000 C is studied. A simple experimental technique where the conductivity is the experimental variable was used. A calibration curve was established for correlating…
In recent years it has become possible to study the properties of nanocrystalline metals through atomic-scale simulations of systems with realistic grain sizes. A brief overview of the main results is given, such as the observation of a reverse Hall-Petch effect - a softening of the metal when the grain size is reduce…
The effect of porosity in a wide range of mesopore diameters ( d p = 20−330 Å) on the dispersion and reducibility of cobalt species in mesoporous silicas is examined using nitrogen adsorption, X-ray diffraction, thermogravimetric analysis, and in situ X-ray absorption. It is shown that modification of mesoporous silic…
We report first-principles total-energy electronic-structure calculations in the density-functional theory performed for hexagonally bonded honeycomb sheets consisting of B, N, and C atoms. We find that the ground state of BNC sheets with particular stoichiometry is ferromagnetic. Detailed analyses of energy bands and…