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排序方式: 共有385条查询结果,搜索用时 31 毫秒
101.
Giovanna Cancelliere Alessia Ciogli Ilaria D’Acquarica Francesco Gasparrini Jelena Kocergin Domenico Misiti Marco Pierini Harald Ritchie Patrizia Simone Claudio Villani 《Journal of chromatography. A》2010,1217(7):990-999
Three brush-type chiral stationary phases (CSPs) differing in the particle size of the starting silica particles have been prepared by covalent grafting of the π-acidic bis-(3,5-dinitrobenzoyl)-derivative of trans-1,2-diaminocyclohexane (DACH-DNB). Starting silica particles of 4.3, 2.6 and 1.9 micron were used to generate the final CSPs using an improved, highly reproducible synthetic methodology, that allowed to assemble and surface-graft the whole chiral selector in only two steps. The different CSPs have been packed in columns of various length and diameters, and fully characterized in terms of flow permeability, kinetic performances and enantioselectivity using a set of test solutes. Very high speed and high resolution applications together with stereodynamic HPLC examples are demonstrated on the columns with reduced particle diameters, on which separations of several enantiomeric pairs are routinely obtained with analysis times in the 15–40 s range. 相似文献
102.
This article describes the construction and validation of a three-dimensional model of the human CCR5 receptor using a homology-based approach starting from the X-ray structure of the bovine rhodopsin receptor. The reliability of the model is assessed through molecular dynamics and docking simulations using both natural agonists and a synthetic antagonist. Some important structural and functional features of the receptor cavity and the extracellular loops are identified, in agreement with data available from site-directed mutagenesis. The results of this study help to explain the structural basis for the recognition, activation, and inhibition processes of CCR5 and may provide fresh insights for the design of HIV-1 entry blockers. 相似文献
103.
Thomas Logan Ritchie 《Journal of statistical physics》2006,122(3):381-398
We provide an explicit construction of the thermodynamic jamming limit for the parking process and other finite range exclusion
schemes on
. By means thereof, a strong law of large numbers for occupation densities is accomplished, and, amongst other results, the
so called “super-exponential” (i.e. gamma) decay of pair correlation functions is established.
Mathematics Subject Classification (1991): 60K99 相似文献
104.
Ritchie C Burkholder E Kögerler P Cronin L 《Dalton transactions (Cambridge, England : 2003)》2006,(14):1712-1714
Unsymmetrical functionalization of a discrete alpha-{SiW12O40} Keggin with two heterometallic building blocks, a Cu(II) dimer and a Cu(II) monomer, results in the formation of [{Cu2(O2CMe)2(5,5'-dimethyl-2,2'-bipy)2}{Cu(5,5'-dimethyl-2,2'-bipy)2}SiW12O40] that displays interesting physical properties. 相似文献
105.
Burke Ritchie 《Optics Communications》2008,281(13):3492-3494
The photon equation of motion previously applied to the Lamb shift is here applied to the anomalous magnetic moment of the electron. Exact agreement is obtained with the QED result of Schwinger. The photon theory treats the radiative correction to the photon in the presence of the electron rather than its inverse as in standard QED. The result is found to be first order in the photon-electron interaction rather than second order as in standard QED, introducing an ease of calculation hitherto unavailable. 相似文献
106.
107.
E. Ritchie 《The Journal of the Operational Research Society》1984,35(10):949-952
The E.O.Q. is derived for constant, continuous demand. For linear increasing demand, Donaldson's analytical solution considers demand bounded by a time horizon H. Although this is mathematically convenient for obtaining a solution, it complicates the calculation of the optimal replenishment policy. Extending the time horizon so that it no longer influences the replenishment times simplifies the calculation of the optimal policy, which is then equivalent to the E.O.Q. calculation for constant demand. 相似文献
108.
109.
Ritchie A. Wessling I. R. Harrison 《Journal of polymer science. Part A, Polymer chemistry》1971,9(12):3471-3489
Poly(vinylidene chloride) precipitates as a crystalline phase during the polymerization reaction. Under the conditions studied, this phase is made up of complex particles with a lamellar substructure. The detailed morphology is very sensitive to reaction medium. The morphology developed by particles formed during polymerization of vinylidene chloride in dioxane suggests a mechanism of polymerization followed by crystallization. The morphology observed in mass polymerization suggests that both processes occurs simultaneously. Kinetic data, however, suggest a solid-phase reaction mechanism for both cases. The results are analyzed by comparison with a model that takes into account the solid-phase morphology. The theoretical analysis is consistent with experimental results if it is assumed that polymerization occurs on the edges of the lamellar crystals. 相似文献
110.
Stowers MA van Wuijckhuijse AL Marijnissen JC Scarlett B van Baar BL Kientz CE 《Rapid communications in mass spectrometry : RCM》2000,14(10):829-833
Matrix-assisted laser desorption/ionization (MALDI) mass spectra were obtained from single biological aerosol particles using an aerosol time-of-flight mass spectrometer (ATOFMS). The inlet to the ATOFMS was coupled with an evaporation/condensation flow cell that allowed the aerosol to be coated with matrix material as the sampled stream entered the spectrometer. Mass spectra were generated from aerosol composed either of gramicidin-S or erythromycin, two small biological molecules, or from aerosolised spores of Bacillus subtilis var niger. Three different matrices were used: 3-nitrobenzyl alcohol, picolinic acid and sinapinic acid. A spectrum of gramicidin-S was generated from approximately 250 attomoles of material using a molar ratio of 3-nitrobenzyl alcohol to analyte of approximately 20:1. A single peak, located at 1224 Da, was obtained from the bacterial spores. The washing liquid and extract solution from the spores were analyzed using electrospray mass spectrometry and subsequent MS/MS product ion experiments. This independent analysis suggests that the measured species represents part of the B. subtilis peptidoglycan. The on-line addition of matrix allows quasi-real-time chemical analysis of individual, aerodynamically sized particles, with an overall system residence time of less than 5 seconds. These results suggest that a MALDI-ATOFMS can provide nearly real-time identification of biological aerosols. Copyright 2000 John Wiley & Sons, Ltd. 相似文献