Study of excretion of ecdysterone in human urine

A study of excretion in human urine of ecdysterone, which is the active component of several over-the-counter supplements such as "Ecdysten", reportedly used by athletes, is presented. The study was performed after oral administration of 20 mg of ecdysterone. The collected urine samples were prepared using the standard screening extraction procedure for the free and conjugated fraction of anabolic steroids, and analyzed by gas chromatography (GC) coupled with quadrupole mass spectrometry (MS) and also with high-resolution mass spectrometry (HRMS). Two ecdysterone metabolites were identified and detected along with unchanged ecdysterone. Accurate mass measurements were made for diagnostic ions, including the molecular ion of the main metabolite of ecdysterone, deoxyecdysone, which, to our knowledge, has not previously been reported in the literature. These accurate mass measurements support the proposed fragmentation scheme.     

Enzymatic fluorimetric determination of the individual bile acids in blood serum

An enzymatic fluorimetric method is described for the determination of total bile acids (cholic acid and deoxycholic acid), primary bile acids (cholic and chen acids and individual bile acids in serum without prior separation of the acids. Total and primary bile acids are determined by equilibrium procedures by conver of the 3α- and 7α-hydroxy bile acids to 3-oxo and 7-oxo bile acids by α-NAD⁺, in the presence of 3α- and 7α-hydroxysteroid dehydrogenase (HSD), respectively, and measurement of the generated NADH fluorimetrically. Chenodeoxycholic acid is determined with 7α-HSD in the presence of cholic and deoxycholic acids by a differential kinetic procedure, and cholic and deoxycholic acids are calculated by difference. Interferents are removed by treatment of serum with Sachrom rein. Only 1.00 ml of serum is required. Low cost, simplicity and reliability are the main features of the method. The recovery of bile acids added to serum averaged 103% (range 83–122%). The method is suitable for routine use in small clinical laboratories.     

Synthesis of periphery-functionalized dendritic molecules using polylithiated dendrimers as starting material

A general method for the functionalization of Si-Cl terminated carbosilane dendritic molecules via organolithium or organomagnesium reagents is described. Quantitative exchange of the bromine atoms of 4-bromophenyl-functionalized dendrimers affords polylithiated species that are valuable starting materials for further functionalization, e.g., into pyridyl alcohols. The latter were successfully applied as catalyst precursors in a ruthenium-mediated ring-closure metathesis reaction.     

Low dose measurement with thick gate oxide MOSFETs

The low dose limit and the accuracy of high sensitivity MOS ionizing radiation dosimeters fabricated at LAAS-CNRS are investigated.     

Comparative study of pretreatment methods for the determination of metals in atmospheric aerosol by electrothermal atomic absorption spectrometry

A comparative study of pretreatment methods for the determination of 10 elements (As, Cd, Pb, V, Ni, Mn, Cr, Cu, Fe, Al) in atmospheric aerosols by electrothermal atomic absorption spectrometry (ETAAS) was conducted. For the digestion of the particulates collected in filters, six methods were compared using a mixture of HNO₃ and HF with or without the addition of various oxidative agents (HClO₄ or H₂O₂) or acids (HCl). The comparative study was performed using loaded cellulose filter samples, which were digested in Parr bombs and heated in a conventional oven at 170 °C for 5 h. The extraction efficiency and blanks were compared and it was proved that the digestion method using only HNO₃–HF extracted most of the metals and gave the lowest blanks. The HNO₃–HF mixture was selected for the development of an improved microwave digestion method specific for aerosol-loaded filters. The operating parameters were optimized, so that quantitative recovery of the reference materials NIST 1649a urban dust and NIST 1648 urban particulate matter was achieved. The blank of cellulose and teflon filters were also determined and compared. Teflon filters present the lowest blanks for all the elements. The obtained limits of detection for each type of filters were adequate for environmental monitoring purposes. ETAAS instrumental operation was also optimized for the compensation and the elimination of interferences. The temperature optimization was performed for each metal in every type of filter and optimized parameters are proposed for 10 elements.     

Oscillatory melting temperature of the vortex smectic phase in layered superconductors

We report on transport measurements of YBa 2Cu 3O (7-delta) single crystals with different oxygen contents in the geometry B, J ||ab (J perpendicularB). Our data show that the vortices become confined between the Cu-O planes below a well-defined temperature at which the effective size 2xi of the vortex core is approximately equal to the period of the Cu-O layers. This confinement strongly increases the vortex liquid freezing temperature. A new melting line is found separating a vortex liquid and a smectic phase, which shows an oscillatory field dependence reflecting differences between commensurate and incommensurate smectic states.     

A synergy of multicriteria techniques to assess additive value models

The assessment of additive value functions in Multicriteria Decision Aid (MCDA) has to face issues of legitimacy and technical difficulties when real decision makers are involved. This paper presents a synergy of three complementary techniques to assess additive models on the whole criteria space. The synergy includes a revised MACBETH technique, the standard MAUT trade-off analysis and UTA-based methods for the assessment of both the marginal value functions and the weighting factors. The paper uses a set of original robustness measures and rules associated with revised MACBETH and UTA in order to manage multiple linear programming solutions and to extract robust conclusions from them. Finally, to illustrate the methods’ synergy, an application example is presented, dealing with the planning of metro extension lines.     

Synthesis of Novel Chiral Diol Ligands for the Enantioselective Reactions

The chiral diols ((,(,((,((-Tetraaryl-1,3-dioxolane-4,5-dimethanols) have been used for the formation of cyclic titanates and similar derivatives of Mg, Al and Zr. These complexes of oxophilic metal centers were employed in catalytic and stiochiometric enantioselective reactions such as enantioselective addition reactions of carbon-centered nucleophiles to aldehydes1, [2+2] cycloadditions2, and Diels-Alder reactions3. So far, the two hydrogen atoms of all this type of diols are in trans form…