Quantification of testosterone undecanoate in human hair by liquid chromatography–tandem mass spectrometry

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.     

Furanoside phosphite–phosphoroamidite and diphosphoroamidite ligands for Cu-catalyzed asymmetric 1,4-addition reactions

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.     

Water-Chain intervention in the ketonization of vinyl alcohol. An ab initio study

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.     

Carleson's counterexample and a scale of Lorentz-BMO spaces on the bitorus

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.     

Sui fasci di cubiche a modulo costante

An improvement of the uniqueness theorem of Wintner for the differential equationx ⁽ⁿ⁾(t)=f(t, x) is given.     

Die Trennung der Alkalien in der Silicatanalyse

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.