Neutrino propagation in a weakly magnetized medium

Neutrino-photon processes, forbidden in vacuum, can take place in the presence of a thermal medium and/or an external electro-magnetic field, mediated by the corresponding charged leptons (real or virtual). Such interactions affect the propagation of neutrinos through a magnetized plasma. We investigate the neutrino-photon absorptive processes, at the one-loop level, for massless neutrinos in a weakly magnetized plasma. We find that there is no correction to the absorptive part of the axial-vector-vector amplitude due to the presence of a magnetic field, to the linear order in the field strength.     

Induced focusing and conversion of a Gaussian beam into an elliptic Gaussian beam

We have presented an investigation of the induced focusing in Kerr media of two laser beams, the pump beam and the probe beam, which could be either Gaussian or elliptic Gaussian or a combination of the two. We have used variational formalism to derive relevant beam-width equations. Among several important findings, the finding that a very week probe beam can be guided and focused when power of both beams are well below their individual threshold for self-focusing, is a noteworthy one. It has been found that induced focusing is not possible for laser beams of any wavelength and beam radius. In case both beams are elliptic Gaussian, we have shown that when power of both beams is above a certain threshold value then the effective radius of both beams collapses and collapse distance depends on power. Moreover, it has been found that induced focusing can be employed to convert a circular Gaussian beam into an elliptic Gaussian beam.     

Correction: Phytol-based novel adjuvants in vaccine formulation: 1. assessment of safety and efficacy during stimulation of humoral and cell-mediated immune responses

This is a correction article.     

Breathers in ferrimagnetic systems

Breathers in discrete nonlinear ferrimagnetic spin lattices are investigated for both easy-axis and easy-plane configurations. The region in frequency space of the formation of breathers is determined and the anticontinuum limit discussed. The monochromatic and the coloured breathers are found out numerically for different parameters and different conditions of excitations.     

Indium-mediated allylation/propargylation of α-diazoketones: a facile synthesis of 1-bromo-2-alkyl- or 2-arylpent-4-en-2-ols

α-Diazoketones undergo smooth allylation with successive bromide insertion with allylindium bromide generated in situ from allyl bromide and indium metal to produce 1-bromo-2-alkyl- or 2-arylpent-4-en-2-ols in high yields. Addition of propargylindium bromide produces 1-bromo-2-alkyl-or 2-arylpent-4-yn-2-ols under similar conditions.     

Electrocatalytic activity of binary Palladium Ruthenium anode catalyst on Ni-support for ethanol alkaline fuel cells

In search for a cheaper anode catalyst for the oxidation of ethanol for development of direct alcohol fuel cells, Pd has been considered here as an interesting substitute for Pt in Pt Ru binary electrodeposite. The binary catalyst when co-deposited on nickel support has been found to increase the current density and decrease the anodic overvoltage significantly with respect to pure Pt, Pd and Ni. Its electrocatalytic capability is also comparable with that of the Pt-Ru binary electrocatalyst on Ni-support, when studied in 1 M EtOH containing 1 M NaOH solution. The effect of loading of Pd Ru electrocatalyst on Ni support has also been tested. The electrocatalytic activity of the electrodes for oxidation of ethanol has been explained by studies of cyclic voltammetry, chronopotentiometry, steady-state polarization, and conjugated scanning electron microscopy–energy dispersion X-ray spectroscopy. It has been found that electrode containing the higher amount of deposit are less affected by carbonaceous poisons.     

Kinetics and mechanism of the reaction oftrans-cyclohexane-1,2-diamine-N N N' N'-tetra-acetatomanganate(III) with substituted thioureas in aqueous medium

Summary The kinetics of reduction of [Mn^III(cydta)]^– (where H₄cydta=trans-cyclohexane-1,2-diamine-N N N' N'-tetraacetic acid) by some thiourea reductants have been studied in aqueous solution by stopped-flow techniques in the pH ranges 2.5–4.5 and 9.2–10.2. An initial increase in absorbance followed by a steady decrease indicated the formation of a precursor complex prior to the electron transfer step. The reactions are first order in both oxidant and reductant. The observed increase in rate in going from low to high pH is attributed to the difference in reactivities of the aqua and hydroxo species of the Mn^III complex; the higher reactivity of the latter is consistent with the formation of a ligand-bridged activated species prior to electron transfer. The reactivity order for the thiourea derivatives follows the order of their reported substituent effects.     

Dynamic molecular recognition in the generation of a new crystal-engineering motif: a unique case study of a dicarboxylic acid with a ditopic receptor favouring a polymeric over a dimeric hydrogen-bonded supramolecular complex

A new crystal-engineering motif has been developed where a ditopic receptor 1 shows a novel syn-syn hydrogen-bonded polymeric supramolecular complex (Fig. 4b) (instead of a 1:1 dimeric syn-syn or polymeric syn-anti complex) giving rise to a hydrogen-bonded stair-like polymeric ribbon structure between the binding groups of the receptor pyridine amide and the carboxyl groups of the guest substrate.     

Synthesis of Pyrimidine Annelated Heterocycles [1]. Regioselective Heterocyclization of 6-Cyclopent-2-enyl-5-hydroxy-1,3-dimethyl-pyrimidine-2,4( 1H, 3H)-dione and 5-Cyclopent-2-enyl-6-hydroxy-1,3-dimethylpyrimidine-2,4( 1H, 3H)-dione

Summary. Two hitherto unreported pyrimidine annelated heterocycles were synthesized from 6-cyclopent-2-enyl-5-hydroxy-1,3-dimethylpyrimidine-2,4(1H,3H)-dione and 5-cyclopent-2-enyl-6-hydroxy-1,3-dimethylpyrimidine-2,4(1H,3H)-dione by reaction with pyridine hydrotribromide or hexamethylenetetramine hydrotribromide. The first one was also obtained by reaction with concentrated sulfuric acid.Received October 28, 2002; accepted October 30, 2002 Published online June 2, 2003     

Structural analyses and magnetic properties of 3D coordination polymeric networks of nickel(II) maleate and manganese(II) adipate with the flexible 1,2-bis(4-pyridyl)ethane ligand

Two novel inorganic-organic hybrid 3D extended networks of Ni(II) and Mn(II) having molecular formulas [(maleate)(2)Ni(3)(bpe)(4)(H(2)O)(4)](NO(3))(2).H(2)O (1) and [(adipate)Mn(bpe)] (2) (bpe = 1, 2-bis(4-pyridyl)ethane), respectively, have been synthesized and characterized by single-crystal X-ray diffraction studies and low-temperature (300-2 K) magnetic measurements. Compound 1 crystallizes in the monoclinic system, space group C2/c (No. 15), with chemical formula C(56)H(62)N(10)Ni(3)O(19), a = 30.955(4) A, b = 12.705(3) A, c = 17.058(5) A, beta = 117.26(2) degrees, and Z = 4. Compound 2 crystallizes in the triclinic system, space group Ponemacr; (No. 2), with chemical formula C(18)H(20)MnN(2)O(4), a = 8.492(2) A, b = 9.444(2) A, c = 11.533(3) A, alpha = 97.19(1) degrees, beta = 94.64(1) degrees, gamma = 105.02(1) degrees, and Z = 2. The structure determination reveals for both a 3D network. Compound 1 contains two crystallographically independent Ni(II) ions in different octahedral environments. Ni(1) lies on an inversion center, and its coordination environment comprises two chelating maleate anions and two bpe nitrogen donors, while the Ni(2) ion is surrounded by meridionally disposed three bpe N atoms, two water molecules, and one oxygen donor from the dicarboxylate anion. Of the three crystallographic independent bpe ligand, one presents an anti and the others a gauche conformation. The corresponding N-to-N distances are 9.344, 6.543, and 6.187 A. Variable-temperature magnetic susceptibility measurement of the complex reveals the existence of a dominant ferromagnetic interaction within the molecule. Compound 2 is composed of Mn(2) dimer units linked by adipate anions to form corrugated 2D sheets which, on interconnection through bpe (anti conformation, N-to-N distance of 9.391 A), produces an interpenetrated 3D alpha-polonium-related type net. Complex 2 reveals to be antiferromagnetic fitting data using a dimeric Mn(II) model that considers negligible magnetic transmission through the carbon skeleton of adipate and the bpe pathway.