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A numerical method using cubic B-splines is presented for solving the linear Boltzmann equation. The collision kernel for the system is chosen as the Wigner-Wilkins kernel. A total of three different representations for the distribution function are presented. Eigenvalues and eigenfunctions of the collision matrix are obtained for various mass ratios and compared with known values. Distribution functions, along with first and second moments, are evaluated for different mass and temperature ratios. Overall it is shown that the method is accurate and well behaved. In particular, moments can be predicted with very few points if the representation is chosen well. This method produces sparse matrices, can be easily generalized to higher dimensions, and can be cast into efficient parallel algorithms. 相似文献
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Yin S Davis RA Shelper T Sykes ML Avery VM Elofsson M Sundin C Quinn RJ 《Organic & biomolecular chemistry》2011,9(19):6755-6760
Bioassay-guided fractionation of the CH(2)Cl(2)/MeOH extract of the Australian marine sponge Pseudoceratina sp. resulted in the purification of four new bromotyrosine alkaloids, pseudoceramines A-D (1-4), along with a known natural product, spermatinamine (5). The structures of 1-5 were determined by spectroscopic methods. Pseudoceramines A (1) and B (2) feature a rare bromotyrosyl-spermine-bromotyrosyl sequence, and pseudoceramine C (3) is the first example of bromotyrosine coupled with an N-methyl derivative of spermidine. Compounds 1-5 were screened for inhibition of toxin secretion by the type III secretion (T3S) pathway in Yersinia pseudotuberculosis. Compounds 2 and 5 inhibited secretion of the Yersinia outer protein YopE (IC(50) = 19 and 6 μM, respectively) and the enzyme activity of YopH (IC(50) = 33 and 6 μM, respectively). 相似文献
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Journal of Thermal Analysis and Calorimetry - In the present framework, the simultaneous effect of rotation, magnetic field, heat source and local thermal non-equilibrium (LTNE) is investigated on... 相似文献
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Use of a urea and guanidine-HCl-propanol solvent system to purify a growth inhibitory glycopeptide by high-performance liquid chromatography 总被引:1,自引:0,他引:1
Reversed-phase high-performance liquid chromatography was used to purify an inhibitory glycopeptide where resolution and recovery were enhanced by using urea or guanidine-HCl-isopropanol-water as a solvent system. Isopropanol alone or other solvent systems that have been proposed for such purification steps were not effective in eluting hydrophobic proteins from the reversed-phase column. The application of the urea or guanidine-HCl solvent systems in the separation and purification of membrane proteins, and other hydrophobic macromolecules, could greatly enhance recovery and efficiency of purification. 相似文献
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