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Abstract The ring‐opening polymerization of L‐lactide with stannous octoate was investigated in the presence of pentaerythritol. By this way it was possible to prepare higher molecular weight star‐shaped poly( L ‐lactide)s compared with the linear ones obtained by stannous octoate only. The weight‐average molecular we…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHydrolytically stable organic triester capped polyoxometalates with catalytic oxygenation activity of formula [RC(CH2O)3V3P2W15O59]6- (R = CH3, NO2, CH2OH)Yuqi Hou and Craig L. HillCite this: J. Am. Chem. Soc. 1993, 115, 25, 11823–11830Publication Date (Print):December 1, 19…
Light microscopy and transmission electron microscopy of thin sections and metal-shadowed specimens showed that the sheath of Leptothrix discophora SP-6 (ATCC 51168) is a tube-like extracellular polymeric structure consisting of a condensed fabric of 6.5-nm-diameter fibrils underlying a more diffuse outer capsular lay…
Several techniques exist to evaluate the water vapor transport characteristics of clothing materials. The most common techniques include guarded hot plate sweating skin simulants and cup-type moisture vapor transmission rate tests. Theoretically, all such tests measure an identical property, water vapor resistance, bu…
The essential oil of Bupleurum fruticescens was investigated qualitatively and quantitatively by GC and GC-MS analyses. The anti-inflammatory activity of the whole essential oil and its major components was also investigated in the rat hindpaw edema model induced by carrageenin or by PGE1. The anti-inflammatory activi…
The demand for energy savings in buildings will increase in the coming years, as the world's attention is drawn towards environmental aspects and energy economizing. Windows which are able to dynamically control the sun radiation through‐put will play an important role. In this respect we have studied two different el…
We report self-consistent, all-electron, local-spin-density calculations of energy bands of iron and cobalt pyrites (${\mathrm{FeS}}_{2}$ and ${\mathrm{CoS}}_{2}$). We find ${\mathrm{FeS}}_{2}$ to be a moderately small-band-gap semiconductor and ${\mathrm{CoS}}_{2}$ to be an almost half-metallic ferromagnet. The predi…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTX-ray photoelectron spectroscopic studies on organic photoconductors: evaluation of atomic charges on chlorodiane blue and p-(diethylamino)benzaldehyde diphenylhydrazoneR. J. Waltman, J. Pacansky, and C. W. Bates, Jr.Cite this: Chem. Mater. 1993, 5, 12, 1799–1804Publication…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA weak antiferromagnetic interaction between manganese(2+) centers through a TCNQ column: crystal structures and magnetic properties of [MnII(tpa)(TCNQ)(CH3OH)](TCNQ)2.cntdot.CH3CN, [MnII(tpa)(.mu.-O2CCH3)]2(TCNQ)2.cntdot.2CH3CN, and [MnII(tpa)(NCS)2].cntdot.CH3CN (tpa = tri…
The crystal-field energy-level structures of three different ${\mathrm{Er}}^{3+}$-doped garnet systems are analyzed and compared in this study. The garnet hosts are ${\mathrm{Y}}_{3}$${\mathrm{Al}}_{5}$${\mathrm{O}}_{12}$ (YAG), ${\mathrm{Y}}_{3}$${\mathrm{Sc}}_{2}$${\mathrm{Al}}_{3}$${\mathrm{O}}_{12}$ (YSAG) doped w…
We review the experimental evidence and qualitative arguments for the existence of small highly regular rings of bonds in amorphous (a-)${\mathrm{SiO}}_{2}$ and selected other ${\mathit{AX}}_{2}$ tetrahedral glasses. The structure and vibrations of planar 3-rings and regular puckered 4-rings in a-${\mathrm{SiO}}_{2}$…
Compositional dependence of spontaneous emission probabilities between initial 4 F 3/2 and terminal 4 I J J = 9/2, 11/2, 13/2, 15/2) levels of Nd 3+ were studied for about 90 samples of silicate, borate, and phosphate glasses using the Judd–Ofelt theory. The effect of the covalency of the Nd–O bond on the magnitude of…
Human profilin is a 15-kDa protein that plays a major role in the signaling pathway leading to cytoskeletal rearrangement. Essentially complete assignment of the 1H, 13C, and 15N resonances of human profilin have been made by analysis of multidimensional, double- and triple-resonance nuclear magnetic resonance (NMR) e…
The phase separation of alloys with two or more components is studied, with emphasis on more than two components. Particular attention is given to differences between multicomponent and binary alloys.Specific topics of the paper include equilibrium theory, aspects of the dynamics, and numerical simulations. In the equ…
An automated structure-refinement program has been developed for X-ray powder diffraction data collected on disordered carbons. The program minimizes the difference between the observed and calculated diffraction profiles in a least-squares sense by optimizing model parameters analogously to the popular Rietveld refin…
Powder diffraction data for semiconductor and metallic states of vanadium dioxide are presented. The structures are refined by Rietveld methods using a monoclinic cell ( a = 5.7529Å, b = 4.5263Å, c = 5.3825Å, β = 122.61°) and space group P2 1 / c for the room temperature data, and a tetragonal cell ( a =4.5540Å, c = 2…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTColored multilayers from transparent submicrometer spheresC. D. Dushkin, K. Nagayama, T. Miwa, and P. A. KralchevskyCite this: Langmuir 1993, 9, 12, 3695–3701Publication Date (Print):December 1, 1993Publication History Published online1 May 2002Published inissue 1 December 1…
Azotobacter vinelandii UWD was grown in a fermentor with glucose medium with and without 0.1% fish peptone (FP) in batch and fed-batch cultures for the production of the natural bioplastic poly-beta-hydroxybutyrate (PHB). Strain UWD formed PHB five times faster than cell protein during growth in glucose and NH(4), but…
Four new synthetic routes to meso-tetraarylporphyrins using a MacDonald-type 2 + 2 condensation are described. Self-condensation of a 5-aryldipyrromethane (e.g., 17) with an aryl-substituted one-carbon bridging unit affords a mixture of tetraarylporphyrins due to acid-catalyzed redistribution reactions. The second and…
Abstract Crystal structures and electrical properties of BETS compounds with tetrahedral anions, MX4− (BETS = bis(ethylenedithio)tetraselenafulvalene; M = Ga, Fe, In; X = Cl, Br) were examined. Every κ-type salt is metallic below 50 K. λ-(BETS)2FeCl4, which is isomorphous to the superconductor GaCl4 salt, undergoes a…