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171.
172.
K. Migléczi Gy. Somorjai M. Pátfalusi G. Tóth Gy. Horváth I. Hazai 《Chromatographia》2004,60(1):S67-S74
GYKI-16084 – (+)-(R)-2-{3-(benzo[1,4]dioxan-2-yl-methylamino)-1-propyl}-3(2H)-pyridazinone hydrochloride – is a new drug candidate for the treatment of benign prostatic hyperplasia. In our study the major metabolites formed in the rat and dog were isolated from dog and rat urine, then their structures were elucidated by means of MS and NMR. A two stage solid phase extraction (SPE) procedure and a semi-preparative HPLC method were developed utilizing various mechanisms of separation. The major metabolites proved to be isomeric glucuronides of the benzodioxane moiety hydroxylated at positions 6 or 7 and {2-(2-carboxyethyl)-3(2H)-pyridazinone}. 相似文献
173.
174.
175.
Stereoselectivity in the intermolecular Pauson-Khand reaction of electron-deficient terminal alkynes
A family of terminal alkyne dicobalthexacarbonyl complexes bearing groups with a range of electron-withdrawing abilities has been synthesized. After submitting these complexes to the intermolecular Pauson-Khand reaction with norbornadiene, electron-deficient substrates afforded up to 26% of the unexpected endo-cyclopentenone. 相似文献
176.
András Sütő 《Journal of statistical physics》2003,112(1-2):375-396
We study condensation of trapped bosons in the limit when the number of particles tends to infinity. For the noninteracting gas we prove that there is no phase transition in any dimension, but in any dimension, at any temperature the system is 100% condensated into the one-particle ground state. In the case of an interacting gas we show that for a family of suitably scaled pair interactions, the Gross–Pitaevskii scaling included, a less-than-100% condensation into a single-particle eigenstate, which may depend on the interaction strength, persists at all temperatures. 相似文献
177.
We present here an improved version of the method introduced by the first author to derive
pointwise gradient estimates for the solutions of one-dimensional parabolic problems. After considering
a general qualinear equation in divergence form we apply the method to the case of a nonlinear
diffusion-convection equation. The conclusions are stated first for classical solutions and then for
generalized and mild solutions. In the case of unbounded initial datum we obtain several regularizing
effects for t > 0. Some unilateral pointwise gradient
estimates are also obtained. The case of
the Dirichlet problem is also considered. Finally, we collect, in the last section, several comments
showing the connections among these estimates and the study of the free boundaries
associated to the solutions of the diffusion-convection equation. 相似文献
178.
José M. Arrieta Neus Cónsul Anibal Rodríguez-Bernal 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2004,23(2):1-14
We prove the existence of nonconstant stable stationary
solutions of
an evolution problem with a nonlinear reaction acting on the
boundary. These solutions present layers at certain points of the
boundary. We also study the behavior of these solutions as the small
parameter appearing in the equation approaches zero and show some
stability properties of the profiles given by these equilibrium
solutions. 相似文献
179.
Summary The potential of liquid chromatography-mass spectrometry (LC-MS) has been studied for the simultaneous determination of sixteen carbamate and organophosphorus pesticides in honeybees using a traditional sample preparation protocol based on acetone extraction and dichloromethane partitioning. The performances of both atmospheric pressure chemical ionization (APCI) and electrospray (ES) interfaces were compared. APCI offered better sensitivity and specificity for a higher range of pesticides. Limits of quantification were from 0.01 to 0.17 mg kg–1, at which recoveries obtained were between 64 and 93%, except for pirimicarb that was at 13%, with relative standard deviations ranging from 7 to 20%. Fenitrothion, fenoxycarb, methiocarb and phoxim were found in bees from Valencian Community beehives at concentrations between 0.03 and 3.75 mg kg–1. 相似文献
180.
We give three formulas expressing the Smale invariant of an immersion f of a (4k−1)-sphere into (4k+1)-space. The terms of the formulas are geometric characteristics of any generic smooth map g of any oriented 4k-dimensional manifold, where g restricted to the boundary is an immersion regularly homotopic to f in (6k−1)-space.The formulas imply that if f and g are two non-regularly homotopic immersions of a (4k−1)-sphere into (4k+1)-space then they are also non-regularly homotopic as immersions into (6k−1)-space. Moreover, any generic homotopy in (6k−1)-space connecting f to g must have at least ak(2k−1)! cusps, where ak=2 if k is odd and ak=1 if k is even. 相似文献