Conductivity relaxation in Ag+ ion conducting PEO–PMMA–PEG polymer blends

In this paper, the electrical conductivity and relaxation studies in two different temperature regions (T?<?T _m and T?>?T _m) on plasticized PEO–PMMA blend polymer electrolyte system with AgNO₃ salt are reported. The polymer electrolyte system has been prepared by solution cast technique and characterized by X-ray diffraction and differential scanning calorimetry. The conduction and relaxation processes at various temperatures have been investigated in the framework of modulus formalism. The distribution of relaxation times is discussed using Argand plot. Variation in ionic conductivity of polymer blends is discussed with the increase of PEO as well as with temperature.     

Reactivity studies of carbon,phosphorus and sulfur‐based acyl sites with tertiary oximes in gemini surfactants

Kinetic studies of the reactions of tertiary oximes (monoisonitroso acetone; MINA and butane 2,3 dione monooxime; BDMO) with some carboxylate (p‐nitrophenyl acetate and p‐nitrophenyl benzoate), phosphate (p‐nitrophenyl diphenyl phosphate and bis (2,4‐dinitrophenyl) phosphate) and sulfonate (p‐nitrophenyl p‐toluene sulphonate) esters in gemini surfactants have been conducted. The observed first‐order rate constant versus surfactant profiles show micelle‐assisted bimolecular reactions involving interfacial ion exchange between bulk aqueous media and micellar pseudophase. Experimental results showed that MINA exhibited better nucleophilic activity towards ester cleavage than BDMO. Pseudophase model has been applied in order to determine micellar second‐order rate constants and binding constants. Copyright © 2013 John Wiley & Sons, Ltd.     

Synthesis,Characterization and Mass Spectrometric Analysis of Cysteine and Valine Adducts of Sulphur Mustard

The synthetic standards for cysteine and valine adducts of sulphur mustard have been synthesized using 2-(2-chloroethylthio) ethanol (half-mustard). These adducts have been recognized as biomarkers for exposure to sulphur mustard. The adducts have been fully characterized using 1 H and 13 C NMR spectroscopy and mass spectrometric techniques.     

Synthesis of C-Disaccharides An Unusual Ring Closure Reaction

Abstract

Reaction of the 4-C-lithiomethyl intermediates, obtained from 4-deoxy-4-C-iodomethylglucopyranosides 5a,b, with open-chain glucose derivative 8 afforded 4-deoxy-4-C-heptitylglucopyranosides 9a,b. Mesylation of the newly generated hydroxy group and then desilylation gave 11a,b which were subjected to ring closure under basic conditions. Surprisingly, no C-bridged cellobiosides 12a,b (or, alternatively the corresponding maltosides) were obtained as major products; with loss of one benzyl alcohol residue the furanosides 13a,b were preferentially formed. Their generation and structural assignment is discussed.     

Size dependent structural and magnetic behaviour of CaFe2O4

CaFe₂O₄ nanocrystalline powders were synthesized through sol–gel treatment in which the stoichiometric mixing of various nitrates involving calcium and iron in presence of citric acid was performed. Subsequently, the as prepared sample was annealed at various temperatures in order to obtain the fine distribution of size including the bulk counterpart. The samples were then characterized using powder X-ray diffraction followed by ⁵⁷Fe Mössbauer spectroscopy, SQUID as well as vibrating sample magnetometry. The results of spectroanalyses revealed that the samples were formed in single phase cubic spinel structure and exhibits room temperature superparamagnetism, except the bulk one, which crystallizes in characteristic orthorhombic structure of CaFe₂O₄ and displays trivial coercivity and remanent magnetization at room temperature.     

Tetramethylguanidinium‐polyallylamine (Tmg‐PA): A new class of nonviral vector for efficient gene transfection

Highly toxic polyallylamine (PA) was reacted with a varying amount of a novel linker, 6‐(N,N,N′,N′‐tetramethylguanidinium chloride) hexanoic acid (Tmg‐HA), to prepare a series of tetramethylguanidinium‐PA (Tmg‐PA) polymers, which were used as vectors for gene transfection. The extent of attachment of the linker, Tmg‐HA, to the PA backbone was determined by 2,4,6‐trinitrobenzene sulfonic acid assay. The modified polymers (Tmg‐PAs), when complexed with pDNA, exhibited good condensation ability. The nanoparticles, so formed, were characterized by their size and zeta potential and were subsequently evaluated for their toxicity and transfection ability on various mammalian cells, viz., HeLa, CHO, and HEK 293 cells. Mobility shift assay revealed that on increasing the percent substitution of Tmg‐HA onto PA (from Tmg‐PA1 to Tmg‐PA6), relatively higher amounts of modified polymers were required to retard the mobility of a fixed amount of DNA. Besides, Tmg‐PA polymers provided sufficient protection (ca. 84–88%) to bound DNA against nucleases and one of the formulations, Tmg‐PA2 (ca. 15% substitution) displayed the highest transfection efficiency outcompeting the commercial transfection reagent, Lipofectamine? with minimal cytotoxicity. More impressively, the transfection efficiency increased despite recording a decrease in the buffering capacity of the grafted polymers suggesting that buffering capacity is not the sole parameter in determining the gene delivery efficiency of a vector system. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

High‐efficiency polymer solar cells based on phenylenevinylene copolymer with BF2‐azopyrrole complex and CN‐PC70BM with solvent additive

Power conversion efficiency (PCE) of phenylenevinylene‐based copolymer with BF₂ azopyrrole complex (PB)/modified PC₇₀BM, that is, CN‐PC₇₀BM bulk heterojunction solar cells improves from 2.16 to 4.90% using a processing additive and drying condition. The results demonstrate that a processing additive and drying condition provides an effective means to control both the surface roughness and finer interpenetrating networks to enhance the exciton dissociation into free charge carriers, charge transportation, and collection. Taking into the account of simple device fabrication process without thermal annealing, the PCE of the polymer solar cell can further improved by chloronapthalene (CN) additive under the fast drying condition. The average carrier lifetimes extracted from the impedance spectra and found to correlate with measured PCEs. At short circuit conditions and illumination, the average charge carrier lifetime was found vary from 16.8 to 32 μs with power conversion efficiencies ranging from 3.0 to 4.9%. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012     

Correlation of soft magnetic properties with free volume and medium range ordering in metallic glasses probed by fluctuation microscopy and positron annihilation technique

Amorphous ribbons of different thicknesses of Co_64.5Fe_3.5Si₁₆B₁₄Ni₂ alloy were synthesized using the melt spinning technique by varying wheel speed. The effect of cooling rate on the ribbon thickness and their soft magnetic properties have been studied. The amorphous structure has been characterized in terms of structural free volume and medium range order (MRO) by positron annihilation spectroscopy and fluctuation electron microscopy techniques. Positron lifetime spectra of amorphous samples showed two lifetime components. The first component was found to be correlated with MRO whereas, the second lifetime component was found to be associated with nanovoid type of defects, and the second component was strongly dependent on processing conditions. It could be established that the coercivity of the amorphous samples produced by the rapid solidification technique mainly depends on the defects formed during processing rather than change induced in MRO.     

First principle electronic structure calculations of ternary alloys Hg1−xMnxTe in zinc-blende structure

We have investigated the structural, electronic, magnetic and optical properties of Hg_1?xMn_xTe in the zinc-blende phase for 0≤x≤1. The calculations were performed by using the full potential linearized augmented plane wave plus local orbitals method within the framework of the density functional theory. The lattice constants of Hg_1?xMn_xTe at different Mn concentrations exhibit Vegard's law perfectly. For spin-up channel the Mn 3d bands are occupied and mixed with the Te 5p bands whereas for spin-down channel the Mn 3d bands are unoccupied. The values of the p–d exchange splitting energy, ?_x(pd) as produced by the Mn 3d states are given. The contribution of the valence band and the conduction band in the process of exchange and splitting is described by the exchange coupling constants N₀α and N₀β. Due to p–d hybridization the magnetic moment of the Mn atom reduces, which results in small local magnetic moments on the non-magnetic Hg and Te sites. The potential applications of Hg_1?xMn_xTe in infrared device have been discussed on the basis of its optical properties.     

Development and validation of a highly sensitive LC‐MS/MS‐ESI method for the determination of bicalutamide in mouse plasma: application to a pharmacokinetic study

A highly sensitive, rapid assay method has been developed and validated for the estimation of bicalutamide in mouse plasma using liquid chromatography coupled to tandem mass spectrometry with electrospray ionization in the negative‐ion mode. The assay procedure involves extraction of bicalutamide and tolbutamide (internal standard, IS) from mouse plasma with a simple protein precipitation method. Chromatographic separation was achieved using an isocratic mobile phase (0.2% formic acid:acetonitrile, 35:65, v/v) at a flow rate of 0.5 mL/min on an Atlantis dC₁₈ column (maintained at 40 ± 1°C) with a total run time of 3.0 min. The MS/MS ion transitions monitored were m/z 428.9 → 254.7 for bicalutamide and m/z 269.0 → 169.6 for IS. Method validation was performed as per FDA guidelines and the results met the acceptance criteria. The lower limit of quantitation achieved was 1.04 ng/mL and the linearity range extended from 1.04 to 1877 ng/mL. The intra‐ and inter‐day precisions were in the ranges of 0.49–4.68 and 2.62–4.15, respectively. Copyright © 2012 John Wiley & Sons, Ltd.