Electrochemical Peculiarities of Mediator-Assisted Bioelectrocatalytic Oxidation of Glucose by a New Type of Bioelectrocatalyst

Russian Journal of Electrochemistry - A protein extract of microbe cells is studied as a bioelectrocatalyst for glucose oxidation. The microbial protein extract prepared from Escherichia coli BB,...     

A novel approach to the quantification of urinary aryl-propionamide-derived SARMs by UHPLC–MS/MS

A simple and sensitive procedure for the quantification of two commonly abused aryl-propionamide-derived selective androgen receptor modulators (SARMs), namely S-4 (GTx-007, andarine) and S-22 (GTx-024, MK-2866, ostarine, enobosarm), has been described. Urine samples were prepared for analysis by means of a dispersive liquid–liquid microextraction using methanol and chloroform as dispersive and extracting solvents, respectively. Factors that might influence the extraction process as well as their optimum conditions were evaluated by Box–Benken and central composite designs. After extraction, the analytes were quantified by UHPLC–MS/MS. The proposed procedure was validated on human urine samples. As a result, for both SARMs the detection limits were observed at 0.05 ng/mL and calibration curves were linear in the concentration range of 0.25–50 ng/mL with the coefficient of determination of 0.998.     

Novel Mixed Complexes of Copper(II) and Ethylenediamine: Synthesis,Crystal Structure,and Catalytic Activity in the Cross-Coupling Reaction of 1-Phenyl-5<Emphasis Type="Italic">H</Emphasis>-tetrazole-5-thiol and Iodobenzene

Two earlier unknown complexes, [Cu(en)₂(Hptt)]Br (Hptt = 1-phenyl-1H-terazole-5-thiol, en = ethylenediamine) and trans-[Cu(en)2(H2O)Br]Br, have been synthesized and characterized using X-ray diffraction analysis. In [Cu(en)₂(Hptt)]Br complex, the copper cation is bonded with the N⁴ atom of tetrazole ring. Catalytic activity of the obtained complexes in cross-coupling reaction of 1-phenyl-5H-tetrazole-5-thiol with iodobenzene is comparable to that of CuBr₂ in the presence of 2 eq. of ethylenediamine.     

Transfer mechanisms in TiAln-type reacting powder mixtures

The contribution of various transfer mechanisms in the synthesis ofTiAl _n-type intermetallides is investigated. The reaction of intermetallide synthesis in a sample from a stoichiometric powder mixture is considered. Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavadenii, Fizika, No. 3, pp. 57–62, March, 1999.     

Elimination of Diurnal,Annual, and Solar Variations in the Matrix Observations of the URAGAN Muon Hodoscope

Physics of Atomic Nuclei - A method for elimination of periodical diurnal, annual, and 27-day and 11-year solar variations in the matrix observations of the URAGAN muon hodoscope was developed. The...     

Technique for Calculating the Critical Current of Inhomogeneous Superconducting Films

Physics of the Solid State - A method for calculating the critical current of an inhomogeneous superconducting film (plate) in different external magnetic fields has been proposed. The...     

N‐Methylbenzoazacrown ethers with the nitrogen atom conjugated with the benzene ring: the improved synthesis and the reasons for the high stability of complexes with metal and ammonium cations

An improved method for the synthesis of formyl derivatives of N‐methylbenzoazacrown ethers is proposed. They are prepared in up to 68% yields over fewer steps and with a much shorter time required for the last step. The stability constants of complexes formed by N‐methylbenzoazacrown ethers and their structural analogs with alkali metal, alkaline‐earth metal and ammonium cations were determined by ¹H NMR titration in CD₃CN. High stability of complexes of N‐methyl derivatives of benzoazacrown ethers is demonstrated, comparable with or even exceeding the stability of benzocrown‐ether complexes and markedly exceeding the stability of complexes of phenylazacrown ethers with the same macrocycle size. The structures of azacrown ethers and their complexes with Ba(ClO₄)₂ were studied by X‐ray diffraction. A high degree of pre‐organization of N‐methylbenzoazacrown ethers toward the formation of complexes with metal and ammonium cations was noted, which is due to the clear‐cut pyramidal geometry of the nitrogen atom and the orientation of the lone electron pairs (LEPs) of most heteroatoms towards the centre of the macroheterocycle. Copyright © 2009 John Wiley & Sons, Ltd.     

Phase equilibria in the Al-Cu-Fe system at a temperature of 853 K in the aluminum enriched region

The phase equilibria in the Al-Cu-Fe system at 853 K in the aluminum enriched region are studied using the methods of scanning and transmission electron microscopy, X-ray phase analysis, and electron probe microanalysis. An isothermal cross section of the system is constructed. Crystal lattice parameters of the phases based on binary and ternary compounds are determined. Approximant phases are not found to form in the quasicrystalline i-phase region.     

Thermodynamic characteristics of formation reactions of the vanadium(V) malonate complex

The coordination equilibria in the vanadium(V)-malonic acid system were studied by calorimetry. The heats of formation reactions of the complex VO₂CH₂(COO) ₂ ^? at 298.15 K and I = 0.50, 0.75, and 1.00 (NaC1O₄) were determined. The standard thermodynamic characteristics of the studied equilibria were calculated.     

Study of ozone interaction with microfibrous filter material by IR Fourier and Raman spectroscopy

Interaction of ozone with microfibrous materials based on polystyrene, acrylonitrile, diacetylcellulose, vinyl chloride and carbon are studied by the methods of IR Fourier and Raman spectroscopy.