Continuous permeation of analytes through a thin poly(dimethylsiloxane) membrane followed by sorbent trapping for their gas chromatographic monitoring

Omeprazole is a benzimidazole compound that acts as a proton-pump inhibitor. Because the metabolism of omeprazole is mainly catalyzed by cytochrome P-450 (CYP) 3A4 and CYP2C19. the genetic polymorphism of CYP2C19 could be of clinical concern in the treatment of acid-related diseases with omeprazole. Therefore, a reliable method for omeprazole phenotyping is desirable in clinical situations. This study has demonstrated the determination of omeprazole and its metabolites in human plasma by liquid chromatography-three-dimensional quadrupole mass spectrometry with a sonic spray ionization interface. The analytical column was YMC-Pack Pro C18(50x2.0 mm I.D.) using acetonitrile-50 mM ammonium acetate (pH 7.25) (1:4) at a flow-rate of 0.2 ml/min. The drift voltage was 30 V. The sampling aperture was heated at 110 degrees C and Shield temperature was 230 degrees C. In the mass spectrum, the molecular ions of omeprazole, hydroxyomeprazole and omeprazole sulfone were clearly observed as base peaks. This method is sufficiently sensitive and accurate for pharmacokinetic studies of omeprazol.     

An approach of majorization in spaces with a curved geometry

The Hardy–Littlewood–Pólya majorization theorem is extended to the framework of some spaces with a curved geometry (such as the global NPC spaces and the Wasserstein spaces). We also discuss the connection between our concept of majorization and the subject of Schur convexity. Several applications are included.     

Self-assembled architecture based on triiron-substituted polyoxomolybdate anion and positively charged polymer

A new self-assembled multilayer architecture was constructed by successive deposition of poly(4-vinylpyridine) partially quaternized with ethylamine (B) and Keggin trilacunary polyoxomolybdate [Aα-PFe₃^III(H₂O)₃Mo₉O₃₇]⁶⁻ (PFe₃Mo₉) on the Au electrode surface, covered with 3-mercapto-1-propanesulfonic acid (MPS). Surface plasmon resonance and cyclic voltammetry measurements were performed at Au/MPS/B/PFe₃Mo₉/B interface in order to investigate the structure and the electrochemical behavior of this electrode. Due to the presence of PFe₃Mo₉, the Au/MPS/B/PFe₃Mo₉/B-modified electrode showed electrocatalytic activity towards H₂O₂ amperometric detection. Additionally, when GOx was deposited as the outermost layer on the abovementioned multilayer structure, the Au/MPS/B/PFe₃Mo₉/B/GOx-modified electrode was able to detect glucose.     

Small Time Uniform Controllability of the Linear One-Dimensional Schrödinger Equation with Vanishing Viscosity

This paper addresses the exact controllability problem of the linear one-dimensional Schrödinger equation perturbed by a vanishing viscosity term depending on a strictly positive parameter. It is shown that, for any time and for each initial datum in a suitable space, there exists a uniformly bounded family of boundary controls. Any weak limit of this family is a control for the linear Schrödinger equation.     

Peralkylation of pentaerythritol for gas chromatographic— mass spectrometric analysis

Summary A rapid and convenient method for the full O-alkylation of pentaerythritol was investigated. The method involves an alkyl halide in a polar aprotic solvent, in the presence of sodium hydroxide. The optimal reaction conditions were studied for methyl iodide, ethyl iodide and bromide, n-propyl bromide and n-butyl bromide. Methyl and propyl derivatives were quantitatively obtained in a short reaction time. The method was applied for the gas chromatographic—mass spectrometric analysis of a commerical pentaerythritol sample.     

Synthesis and Biological Screening of New Cyano-Substituted Pyrrole Fused (Iso)Quinoline Derivatives

Several new cyano-substituted derivatives with pyrrolo[1,2-a]quinoline and pyrrolo[2,1-a]isoquinoline scaffolds were synthesized by the [3 + 2] cycloaddition of (iso)quinolinium ylides to fumaronitrile. The cycloimmonium ylides reacted in situ as 1,3-dipoles with fumaronitrile to selectively form distinct final compounds, depending on the structure of the (iso)quinolinium salt. Eleven compounds were evaluated for their anticancer activity against a panel of 60 human cancer cell lines. The most potent compound 9a showed a broad spectrum of antiproliferative activity against cancer cell lines representing leukemia, melanoma and cancer of lung, colon, central nervous system, ovary, kidney, breast and prostate cancer. In vitro assays and molecular docking revealed tubulin interaction properties of compound 9a.     

Determination of Antioxidant Capacity by Using Xanthine Oxidase Bioreactor Coupled with Flow‐through H2O2 Amperometric Biosensor

A new flow system for antioxidant capacity (AOC) estimation, consisting of a bioreactor, containing immobilized xanthine oxidase (XOD), coupled with a H₂O₂ amperometric biosensor, based on Os‐wired horseradish peroxidase, was developed. The H₂O₂, resulting from the enzymatic reaction between xanthine (XA) and XOD, was amperometrically monitored at ?0.1 V vs. Ag/AgCl/KCl_sat, in order to avoid the electrochemical interferences. Two protocols were used to perform the AOC evaluation: “steady‐state”, when the antioxidant (AOX) was injected in the XA flow, and “transient state”, when XA and AOX were simultaneously injected in the carrier flow. The AOC of some commercial beverages were evaluated and compared with those obtained with 2,2‐diphenyl‐1‐picrylhydrazyl radical and Folin–Ciocalteu methods.     

Solution behavior of progressively quaternized poly(dimethylaminoethyl methacrylate) as a function of charge density

Hydrodynamic behavior of progressively quaternized poly(dimethylaminoethyl methacrylate) (PDMAEM) in dilute and semi-dilute salt–free aqueous solutions as a function of molar mass and charge density, which varied from 5 up to 100 mol%, was studied. The role of long range electrostatic interactions on the viscosity and on the position and value of the reduced viscosity corresponding to the peak, η_red,p, as a function of the charge density of polycation has been evaluated. The overlap concentration of polyelectrolytes, c^∗, has been evaluated as the inverse of the intrinsic viscosity determined by fitting the viscometric results on Rao equation. The values of c^∗ have been discussed as a function of polyion molar mass and charge density. The c^∗ values calculated in the frame of Odijk model for polyelectrolytes having quaternization degree ?50 were lower but comparable with those determined by viscometry, for the same molar mass.     

Exceptional electrochemical performance of Si-nanowires in 1,3-dioxolane solutions: a surface chemical investigation

The effect of 1,3-dioxolane (DOL) based electrolyte solutions (DOL/LiTFSI and DOL/LiTFSI-LiNO(3)) on the electrochemical performance and surface chemistry of silicon nanowire (SiNW) anodes was systematically investigated. SiNWs exhibited an exceptional electrochemical performance in DOL solutions in contrast to standard alkyl carbonate solutions (EC-DMC/LiPF(6)). Reduced irreversible capacity losses, enhanced and stable reversible capacities over prolonged cycling, and lower impedance were identified with DOL solutions. After 1000 charge-discharge cycles (at 60 °C and a 6 C rate), SiNWs in DOL/LiTFSI-LiNO(3) solution exhibited a reversible capacity of 1275 mAh/g, whereas only 575 and 20 mAh/g were identified in DOL/LiTFSI and EC-DMC solutions, respectively. Transmission electron microscopy (TEM) studies demonstrated the complete and uniform lithiation of SiNWs in DOL-based electrolyte solutions and incomplete, nonuniform lithiation in EC-DMC solutions. In addition, the formation of compact and uniform surface films on SiNWs cycled in DOL-based electrolyte solutions was identified by scanning electron microscopic (SEM) imaging, while the surface films formed in EC-DMC based solutions were thick and nonuniform. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy were employed to analyze the surface chemistry of SiNWs cycled in EC-DMC and DOL based electrolyte solutions. The distinctive surface chemistry of SiNWs cycled in DOL based electrolyte solutions was found to be responsible for their enhanced electrochemical performances.