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991.
The cyclocondensation of tetrabromocyclopropene and furan leads directly to a halogenated oxabicyclo[3.2.1]octadiene derivative. Over the past several years, we have utilized these compounds as intermediates for natural product synthesis. Herein, we describe the preparation of nonracemic dibromoenone building blocks from the racemic cycloadduct. Conversion of the adduct to a mixture of tartrate-derived ketals followed by separation of the diastereomers and hydrolysis allows for the formation of novel chiral synthons with either absolute configuration. 相似文献
992.
McMahon MI Nelmes RJ Wright NG Allan DR 《Physical review. B, Condensed matter》1993,48(22):16246-16251
993.
Antonio M. Peralta Ignacio Villanueva J.D. Maitland Wright Kari Ylinen 《Journal of Mathematical Analysis and Applications》2007,325(2):968-974
Let X be a Banach space. Then there is a locally convex topology for X, the “Right topology,” such that a linear map T, from X into a Banach space Y, is weakly compact, precisely when T is a continuous map from X, equipped with the “Right” topology, into Y equipped with the norm topology. When T is only sequentially continuous with respect to the Right topology, it is said to be pseudo weakly compact. This notion is related to Pelczynski's Property (V). 相似文献
994.
Hadwiger’s Theorem states that En-invariant convex-continuous valuations of definable sets in Rn are linear combinations of intrinsic volumes. We lift this result from sets to data distributions over sets, specifically, to definable R-valued functions on Rn. This generalizes intrinsic volumes to (dual pairs of) non-linear valuations on functions and provides a dual pair of Hadwiger classification theorems. 相似文献
995.
A novel library of resin-bound receptors within a cross-reactive differential array for the identification and discrimination of tripeptides and tripeptide mixtures is reported. Pattern recognition using principal component analysis showed complete discrimination of four similar tripeptides and three tripeptide mixtures. The library is comprised of a Cu(II)-centered core with two proximally appended tripeptide arms emanating outward. One tripeptide arm was prepared using combinatorial chemistry to generate the differential nature of the library. Thirty resin-bound receptors were randomly selected from the library and placed within a silicon microchip array that included integrated microfluidics elements, and an indicator-uptake assay was used for colorimetric signaling. The indicator Orange G yielded an accurate measure of the degree of association between receptors and analytes as determined by kinetic analysis of the indicator-uptake assays. Within this paper we detail the method used for differential sensing using a novel receptor library. This work further demonstrates the power and utility of a differential array of synthetic receptors for identification and discrimination of complex bioanalytes. 相似文献
996.
Menger FM Seredyuk VA Apkarian RP Wright ER 《Journal of the American Chemical Society》2002,124(42):12408-12409
Cryo-etch-HRSEM is introduced as a useful method for exploring colloidal systems. The method fast freezes an aqueous sample (to -105 degrees C in 6-7 ms), removes some or all of the surface water by sublimation (etching), and magnifies the resulting colloidal structure by up to a million. Three new structurally similar gemini surfactants served to illustrate the technique. One gemini formed a gel whose delicate fractal-like molecular web could be observed after 10-min etching. A second formed a coacervate with a more hydrated porous structure. The third displayed a "bumpy" surface consistent with spherical vesicles projecting from the vitreous ice. The information-content of cryo-etch-HRSEM is pictorial but distinctive in nature. 相似文献
997.
Treatment of Os(κ2-S2CNMe2)H(CO)(PPh3)2 with HSiMeCl2 or HSiCl3 gives in high yield Os(κ2-S2CNMe2)(SiMeCl2)(CO)(PPh3)2 (1) or Os(κ2-S2CNMe2)(SiCl3)(CO)(PPh3)2 (2), respectively. The crystal structures of both compounds have been determined and the Os-Si distances are 2.3672(10) Å for 1 and 2.3449(12) Å for 2. In solution, and under forcing conditions, both compounds are extraordinarily unreactive towards hydroxide ions. 相似文献
998.
999.
Kurt D. Hamman Richard L. Williamson Eric D. Steffler Christopher T. Wright J. Richard Hess Peter A. Pryfogle 《Applied biochemistry and biotechnology》2005,121(1-3):71-80
Design and development of improved harvesting, preprocessing, and bulk handling systems for biomass requires knowledge of
the biomechanical properties and structural characteristics of crop residue. Structural analysis of wheat stem cross-sections
was performed using the theory of composites and finite element analysis techniques. Representative geometries of the stem’s
structural components including the hypoderm, ground tissue, and vascular bundles were established using microscopy techniques.
Material property data for the analysis was obtained from measured results. Results from the isotropic structural analysis
model were compared with experimental data. Future work includes structural analysis and comparison with experimental results
for additional wheat stem models and loading configurations. 相似文献
1000.