Determination of Synacthen in urine for sports drug testing by means of nano‐ultra‐performance liquid chromatography/tandem mass spectrometry

Doping control analysis of performance‐enhancing peptides in urine represents a challenging requirement in modern sports drug testing. Low dosing, effective metabolism and short half‐life lead to target concentrations in the low fmol/mL range in urine. Synthetic adrenocorticotropic hormone (1‐24, Syn‐ACTH‐en) shares all these characteristics and improved analytical performance is required for its sufficient determination by means of liquid chromatography/tandem mass spectrometry (LC/MS/MS). The desired effects for cheating sportsmen are mainly due to enhanced release of corticosteroids as well as androgenic steroids into the circulation after systemic administration of the drug. Immunoaffinity purification with coated magnetic beads and subsequent liquid chromatography with nano‐ultra‐performance liquid chromatography (UPLC) coupled to tandem mass spectrometry (high resolution/high mass accuracy) of Synacthen from urinary specimens is described in the present study. The general proof of principle was obtained by analysis of excretion study urine samples and validation was performed with focus on the limit of detection (3 pg/mL), linearity, precision (<20%), recovery (～30%), robustness, specificity and stability. For all experiments, the ACTH fragment 1‐17 was used as the internal standard. Copyright © 2009 John Wiley & Sons, Ltd.     

The Arrow of Time: From Universe Time-Asymmetry to Local Irreversible Processes

In several previous papers we have argued for a global and non-entropic approach to the problem of the arrow of time, according to which the “arrow” is only a metaphorical way of expressing the geometrical time-asymmetry of the universe. We have also shown that, under definite conditions, this global time-asymmetry can be transferred to local contexts as an energy flow that points to the same temporal direction all over the spacetime. The aim of this paper is to complete the global and non-entropic program by showing that our approach is able to account for irreversible local phenomena, which have been traditionally considered as the physical origin of the arrow of time.     

Controllability of the discrete-spectrum Schrödinger equation driven by an external field

We prove approximate controllability of the bilinear Schrödinger equation in the case in which the uncontrolled Hamiltonian has discrete non-resonant spectrum. The results that are obtained apply both to bounded or unbounded domains and to the case in which the control potential is bounded or unbounded. The method relies on finite-dimensional techniques applied to the Galerkin approximations and permits, in addition, to get some controllability properties for the density matrix. Two examples are presented: the harmonic oscillator and the 3D well of potential, both controlled by suitable potentials.     

Isoperimetry and symmetrization for Sobolev spaces on metric spaces

Using isoperimetry we obtain new symmetrization inequalities that allow us to provide a unified framework to study Sobolev inequalities in metric spaces. The applications include concentration inequalities, Poincaré inequalities, as well as metric versions of the Pólya–Szegö and Faber–Krahn principles. To cite this article: J. Martín, M. Milman, C. R. Acad. Sci. Paris, Ser. I 347 (2009).     

A diffusion-consumption problem for oxygen in a living tissue perfused by capillaries

We study a mathematical model describing the nonlinear diffusion of oxygen in a living tissue, in presence of consumption due to metabolism. The tissue is perfused by a system of parallel capillaries in which oxygen is carried by the blood both in the form of gas freely diffusing in plasma and bound to hemoglobin. We prove global existence of a unique smooth solution to the resulting parabolic-hyperbolic system.     

Vibrational spectra and H-bondings in anhydrous and monohydrate α-Zr phosphates

A new FTIR and FT-Raman investigation on α-zirconium phosphate (Zr(HPO₄)₂·H₂O) and its anhydrous form has been performed in order to obtain an affordable assignment of their vibrational spectra as well as to highlight the hydrogen bonding structure formed by the P-OH groups and the intercalated water molecules. To this end the spectral changes induced by both temperature and isotopic exchange were observed on several high-purity grade samples of different morphology especially prepared and well characterized by SEM, RX, DSC and TGA. In particular, it is also presented as a detailed discussion of the results obtained by FTIR-PAS for different sample morphology. The observed spectra have been analyzed and interpreted according to the α-Zr(HPO₄)₂·H₂O crystal structure and H-bond geometry. The obtained results allowed to clarify the mechanism of the α-Zr(HPO₄)₂·H₂O→α-Zr(HPO₄)₂ dehydration process as well as the H-bonding changes involved in the high temperature phase transition of anhydrous α-Zr(HPO₄)₂.     

Sol-gel preparation of In2O3-Al2O3 supports with controlled textural and structural properties

Alumina supports with a very narrow pore size distribution were obtained with indium-doped alumina prepared by the sol-gel method. The formation of aluminum in pentahedral coordination was identified by ²⁷Al NMR-MAS-spectroscopy. A good correlation was obtained with the Al^V NMR-MAS intensity signal and the activity in isopropanol dehydration. The insertion of In³⁺ substituting some Al³⁺ in the alumina network was suggested.