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991.
Ah-lim Tsai Eva Strobel-Jager Kenneth K. Wu 《Journal of computer-aided molecular design》1991,5(2):135-148
Summary To elucidate the conformation of receptor-associated prostacyclin (PGI2), we first performed structure-activity correlation analysis of over 200 PGI2 analogues and derived from this analysis several crucial features pertaining to structural requirements for PGI2 activity [Ah-lim Tsai and Kenneth K. Wu, Eicosanoids, 2 (1989) 131–143]. These structural features proved to be useful guidelines for selecting model molecules for further investigations by molecular mechanics. By properly selecting four analogues with either rigid or uniquely oriented -side chain structure for geometric fitting, we succeeded in maximally minimizing the degree of freedom of the carboxylate terminus of PGI2. We were able to define the spatial relationship among the four critical functional groups, i.e., C1-COOH, C6a-O, C11-OH and C15-OH. More information is needed, however, to define the geometry of the -side chain, particularly for the moiety beyond C15. Nevertheless, results from structure-activity correlation analysis and molecular modeling provide useful information regarding the conformation of receptor-associated PGI2, which assumes an elongated conformation instead of the traditional hairpin structure. 相似文献
992.
Wu Shaoping 《数学学报(英文版)》1991,7(1):4-12
LetL be a self-adjoint linear operator andN be the gradient of a functional ϕ, which is almost quadratic. We first give a theorem on the surjectivity of the operatorL+N, then apply the result to semilinear elliptic systems:
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A generalized on-shell (GOS) renormalization scheme of QCD is developed to evaluate the renormalization of heavy quark wave functions and currents. All large logarithms arising from the physical range of quark masses and momentum transferq
2 can be absorbed into wave function and vertex renormalization. Our results are more general than those of the heavy quark effective theory and agree with the latter only at zero recoil. The proposed GOS scheme is very suitable for the /m
Q
expansion. As an application we discuss the renormalization of the flavour changing currentsb-c, t-b andt-c.Supported by Bundesministerium für Forschung und Technologie (BMFT) 相似文献
999.
Bistatic scattering by arbitrarily shaped objects with rough surface at optical and infrared frequencies 总被引:2,自引:0,他引:2
The scattering cross sections for arbitrarily shaped dielectric objects with rough surface are determined for optical and infrared frequencies using the Kirchhoff approximation. The formula of the coherent scattering cross section is derived, and numerical method of incoherent scattering cross section is given. As a specific example, the infrared laser scattering cross sections of rough spheres are calculated at 1.06 m. 相似文献
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