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121.
Oscar J. Pozo Koen Deventer Peter Van Eenoo Robert Rubens Frans T. Delbeke 《Biomedical chromatography : BMC》2009,23(8):873-880
Testosterone undecanoate (T‐C11) can be used by athletes in order to improve performance. After oral intake, T‐C11 is rapidly metabolized, hampering discrimination between exogenous and endogenous testosterone. A possible alternative is to detect the intact ester in hair. A method based on liquid chromatography–tandem mass spectrometry was developed for the determination of T‐C11 in hair. The sample procedure consisted of digestion of 200 mg of pulverized hair with tris(2‐carboxyethyl)phosphine hydrochloride and liquid–liquid extraction with n‐pentane. Several parameters such as the mobile phase, the ionization source and the washing step were optimized. The method was validated at different spiked levels obtaining satisfactory values for accuracy (between 92 and 102%) with relative standard deviations lower than 7% and a limit of detection of 0.2 ng/g. The applicability of the method was checked by the analysis of three samples from patients using T‐C11. A peak for the analyte was detected in all samples with concentrations between 0.4 and 8.4 ng/g. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
122.
Eva Raluy Oscar Pàmies Montserrat Diéguez Stephane Rosset Alexander Alexakis 《Tetrahedron: Asymmetry》2009,20(16):1930-1935
A sugar-based phosphite–phosphoroamidite and diphosphoroamidite ligand library L1–L5a–g was tested in the asymmetric Cu-catalyzed 1,4-conjugate addition reactions of β-substituted and β,β′-disubstituted enones. Our results indicated that the selectivity was strongly dependent on the ligand parameters and on the substrate structure. Moderate-to-good enantioselectivities (ees up to 84%) were obtained in the 1,4-addition of several types of β-substituted cyclic and linear substrates. Of particular note is the high enantioselectivity (ees up to 90%) obtained for the more challenging β,β′-disubstituted 3-methyl-cyclohexenone. 相似文献
123.
Oscar Leppig 《Analytical and bioanalytical chemistry》1882,21(1):433-434
124.
125.
We construct the induced representations of the null-plane quantum Poincaré and quantum kappa Galilei algebras in (1+1) dimensions. The induction procedure makes use of the concept of module and is based on the existence of a pair of Hopf algebras with a nondegenerate pairing and dual bases. 相似文献
126.
The ketonization of vinyl alcohol in aqueous solution has been studied by means of ab initio calculations, using the STO -3G basis set. The intervention of a chain of two water molecules reduces dramatically the potential barrier. This result agrees with experimental facts. 相似文献
127.
We introduce a full scale of Lorentz-BMO spaces BMO
L
p,q
on the bidisk, and show that these spaces do not coincide for different values ofp andq. Our main tool is a detailed analysis of Carleson's construction in [C].
The first author gratefully acknowledges support by the LMS and Proyecto BFM2002-04013. The second author gratefully acknowledges
support by EPSRC and by the Nuffield Foundation. 相似文献
128.
Oscar Chisini 《Rendiconti del Circolo Matematico di Palermo》1916,42(1):59-64
An improvement of the uniqueness theorem of Wintner for the differential equationx (n)(t)=f(t, x) is given. 相似文献
129.
Oscar Cantoni 《Fresenius' Journal of Analytical Chemistry》1925,67(1-2):33-34
Zusammenfassung Die alte Berzelius-Methode zur Alkalibestimmung in Silikaten wird bedeutend vereinfacht, wenn man nach dem Flusss?ure-Aufschluss
die Schwefels?ure vollst?ndig verjagt, die Sulfate schwach glüht, und die Masse mit heissem Wasser auszieht. 相似文献
130.