Antibacterial,SOD mimic and nuclease activities of copper(II) complexes containing ofloxacin and neutral bidentate ligands

Drug‐based mixed‐ligand copper(II) complexes of type [Cu(OFL)(Aⁿ)Cl]·5H₂O (OFL = ofloxacin, A¹ = pyridine‐2‐carbaldehyde, A² = 2,2′‐bipyridylamine, A³ = thiophene‐2‐carbaldehyde, A⁴ = 2,9‐dimethyl‐1,10‐phenanthroline, A⁵ = 2,9‐dimethyl‐4,7‐diphenyl‐1,10‐phenanthroline, A⁶ = 4,5‐diazafluoren‐9‐one, A⁷ = 1,10‐phenanthroline‐5,6‐dione and A⁸ = 5‐nitro‐1,10‐phenanthroline) were synthesized and characterized. Spectral investigations of complexes revealed square pyramidal geometry. Viscosity measurement and absorption titration were employed to determine the mode of binding of complexes with DNA. DNA cleavage study showed better cleaving ability of the complexes compared with metal salt and standard drug by conversion of a supercoiled form of pUC19 DNA to linear via circular. From the SOD mimic study, concentration of complexes ranging from 0.415 to 1.305 µM is enough to inhibit the reduction rate of NBT by 50% (IC₅₀) in the NADH‐PMS system. Antibacterial activity was assayed against selective Gram‐negative and Gram‐positive microorganisms using the doubling dilution technique. Copyright © 2010 John Wiley & Sons, Ltd.     

Approximate solvability of hammerstein equation

In this paper we obtain approximate solvability results for hammerstein operator equation using the idea of asymptotic compactness and theory of monotone operators.

As an application we discuss numerical results of a concrete example involving two point nonlinear boundary value problem.     

Brønsted acid promoted intramolecular cyclization of O-alkynyl benzoic acids: Concise total synthesis of exserolide F

Herein we report the stereoselective total synthesis of Exserolide F. The key step involves triflic acid catalyzed highly regioselective intramolecular cyclization of an O-alkynyl benzoic acid derivative to accomplish the core isocoumarin skeleton of the natural product via 6-endo-dig mode of cyclization. The other important steps are: Sharpless asymmetric epoxidation, Barbier propargylation, Sonogashira coupling en route to access the O-alkynyl benzoic acid derivative.     

Soliton dynamics in an inhomogeneous Bose-Einstein condensate driven by linear potential

In this paper we study the propagation of solitons in a Bose-Einstein condensate governed by the time dependent one dimensional Gross-Pitaevskii equation managed by Feshbach resonance in a linear external potential. We give the Lax pair of the Gross-Pitaevskii equation in Bose-Einstein condensates and obtain exact N-soliton solution by employing the simple, straightforward Darboux transformation. As an example, we present exact one and two-soliton solution and discuss their transmission, interaction and dynamic properties. We further calculate the particle number, momentum and energy of the solitons and discuss their conservation laws. Knowledge of soliton dynamics helps us in understanding the physical nature of the condensate and in the calculation of the thermodynamic properties.     

A new general R-matrix theory of collinear reactions and its application to the H + H2 reaction

A new general R-matrix theory of collinear reactions is developed by using the polar coordinate for the inner interaction region and the Cartesian coordinate for the two outer (reactants and products) asymptotic regions. The theory is applied to the collinear H + H₂ exchange reaction.     

Solidification of selenium melt under pressure up to 6.5 GPa

Abstract

High purity selenium samples were melted under high pressure (≤6.4 GPa) and quenched at various rates ranging from 2 K s^?1 to 500 K s^?1 and the recovered material was examined by X-ray diffraction and electron microscopy. In the entire range of pressure and cooling rate, the melt was found to solidify into a polycrystalline aggregate of the trigonal phase of selenium. The samples obtained by slow cooling of the melt at 6.4 GPa contain, in addition to crystalline phase, regions which appear to be amorphous.