Use of a recyclable poly(<Emphasis Type="Italic">N</Emphasis>-vinyl carbazole) palladium(II) complex catalyst: Heck cross-coupling reaction under phosphine-free and aerobic conditions

A poly(3,6-dibenzaldimino N-vinyl carbazole) Pd(II) complex has been synthesized and characterized by physicochemical and spectroscopic techniques. The complex was found to be highly active toward hydrogenation reactions of various organic substrates under atmospheric pressure at ambient temperature. A tentative reaction mechanism is proposed on the basis of kinetic studies and isolation of reactive intermediates. The catalyst shows good conversion rates, thermal stability and recyclability.     

Nanocrystalline undoped tetragonal and cubic zirconia synthesized using poly-acrylamide as gel and matrix

Nanocrystalline zirconia powders with tetragonal and cubic structure have been prepared from ZrO₂-polyacrylamide gel and precipitated zirconia in polyacrylamide matrix respectively. X-ray diffraction results of the samples annealed at high temperatures show that the tetragonal and cubic form, obtained from the gel, are fairly stable in air up to 1,173 K and partially stable in inert atmosphere, up to 1,273 K. The stability at such high temperatures is due to the presence of oxygen vacancies in zirconia sample, incorporated in the process of decomposition of polymer.     

Synthetic and Thermal Studies of Polymeric Chelates of Some Bis-Biurets with First Transition Series Metals

Some new coordination polymers have been synthesized by combining adipyl bis-biuret and azelyl bis-biuret with metals of first transition series viz Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). They were characterized by elemental analysis, infrared and reflectance spectral and magnetic studies. A detailed thermal study was carried out and thermal stability compared. The results obtained have been discussed.This revised version was published online in November 2005 with corrections to the Cover Date.     

Application of dial-gage and laser speckles for ultra-low thermal-expansion measurements using push-rod dilatometers

Conversion of conventional push-rod dilatometers for ultra-low thermal-expansion measurements is described. The method is based on the determination of the displacement of the probe-rod by ultra-precise dial-gage measurements by means of a laser-speckle technique. The movement of speckles created in space by the laser beam incident on an aluminum foil attached to the needle of the gage is observed for the measurements. It has been found that the sensitivity of the modified dilatometer is orders of magnitude higher than the existing LVDT approach.     

Finslerian Multi-Dimensionality,Associated Gauge Fields,and Stochastic Space-Time

The theory is constructed which elucidates all the gauge fields associated with fibration of the tangent vectors and of the vectors of higher degrees of tangency. The approach synthesizes intrinsically the Einstein equations with the Yang-Mills equations and gives an adequate framework for extending the physical field equations. Then, by considering the statistical behaviour of internal variables, it is possible to get a deeper insight in understanding the origin of quantum laws. Actually, we construct what may be called the general relativity in vector fibrations over space-time manifold.     

Monodromy Deformation Approach to Nonlinear Equations — A Survey

Monodromy deformation approach to nonlinear partial differential equation is discussed in a pedestrian's way. The whole methodology is discussed on the basis of Massive Thirring Model. In the first section of our paper we discuss the basic terminologies amociated with the deformation problem. In the next part the problem is defined on the basis of the Lax pairs for the Thirring model, and it is explicitly demonstrated that how one can determine the asymptotic expansions near a regular and irregular singularity, and hence the Stokes multipliers. Thirdly we show how to determine the “third” equation in according to Its. In the determination of the asymptotic expansion we have discussed the role played by both the WKB approximation and the series solution. In the fourth section we briefly consider the problem when the nonlinear field variables are taken to be fermionic.     

Polyphenolic Composition,Antioxidant, Antiproliferative and Antidiabetic Activities of Coronopus didymus Leaf Extracts

Coronopus didymus (Brassicaceae) commonly known as lesser swine cress has been reported to be used for its pharmacological activities. This study aimed to evaluate the medicinal potential of C. didymus extracts against cancer, diabetes, infectious bacteria and oxidative stress and the identification of bioactive compounds present in these extracts. The effects of using different solvents for the extraction of C. didymus on the contents of major polyphenols and biological activities were investigated. Plant sample was shade dried, ground to a fine powder, and then soaked in pure acetone, ethanol and methanol. The highest contents of major polyphenols were found in methanol-based extract, i.e., chlorogenic acid, HB acid, kaempferol, ferulic acid, quercetin and benzoic acid with 305.02, 12.42, 11.5, 23.33, 975.7 and 428 mg/g of dry weight, respectively, followed by ethanol- and acetone-based extracts. The methanol-based extract also resulted in the highest antioxidant activities (56.76%), whereas the highest antiproliferative (76.36) and alpha glucosidase inhabitation (96.65) were demonstrated in ethanol-based extracts. No antibacterial property of C. didymus was observed against all the tested strains of bacteria. Further studies should be focused on the identification of specific bioactive compounds responsible for pharmacological activities.