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Kolkata, India

Dey A.,Presidency College
African journal of traditional, complementary, and alternative medicines : AJTCAM / African Networks on Ethnomedicines | Year: 2012

Snakebite has been a major cause of mortality across the tropical countries including Indian subcontinent. The present review deals with the enormous amount of ethnobotanical work performed in the last few years involving use of different plants against snakebite in Indian subcontinent (India, Bangladesh, Pakistan and Nepal). From a variety of literature sources the data has been compiled mentioning the plants, parts used, dosage, mode of administration, name of the ethnic communities, geographical locations etc. depending on the availability of information. Source

Datta J.,Bengal Engineering and Science University | Dutta A.,Bengal Engineering and Science University | Biswas M.,Presidency College
Electrochemistry Communications | Year: 2012

This work reports improved electrode kinetics of ethanol oxidation on the conducting polymer composite matrix, poly-vinyl carbazole (PNVC) crossed linked with V 2O 5 and embedded with Pt-Pd nano crystallites. The metal incorporated polymer composite produces much higher current for ethanol electro-oxidation in alkaline medium compared to their carbon supported counterpart. The former also exhibits higher tolerance to CO-poisoning leading to a satisfactory level of ethanol conversion to the end products as estimated by chromatographic analysis. The structure and morphology of the catalysts surface were determined by SEM and XRD analysis. Various electrochemical techniques were employed to evaluate the kinetic parameters related to electro-oxidation of ethanol. Activation energy for the oxidation reaction is remarkably reduced, using the PNVC support, consistently throughout an extended potential region. © 2012 Elsevier B.V. All rights reserved. Source

Acharyya M.,Presidency College
European Journal of Physics | Year: 2010

Usually, we study the statistical behaviour of noninteracting fermions in finite (mainly two and three) dimensions. For a fixed number of fermions, the average energy per fermion is calculated in two and in three dimensions, and it becomes equal to 50% and 60% of the Fermi energy respectively. However, in higher dimensions this percentage increases as the dimensionality increases, and in infinite dimensions it becomes 100%. This is an interesting result, at least pedagogically, which implies that all fermions are moving with Fermi momentum. This result is not yet discussed in standard text books of quantum statistics. Here this fact is discussed and explained. I hope that this letter will be helpful for graduate students to study the behaviours of free fermions in generalized dimensionality. © 2010 IOP Publishing Ltd. Source

Mukherjee P.K.,Presidency College
Journal of Chemical Physics | Year: 2010

We present a mean-field description of the phase transitions, which are obtained when cooling from the isotropic liquid to the first liquid crystalline phase in compounds composed of achiral banana-shaped molecules. We put special emphasis on the isotropic to antiferroelectric B2 phase transition. The free energy is written in terms of the coupled order parameters including the antiferroelectric polarization. We present a detailed analysis of the different phases that can occur and analyze the question under which conditions a direct isotropic to antiferroelectric B2 phase transition is possible when compared with other phase transitions. The theoretical results are found to be in qualitative agreement with all published experimental results. © 2010 American Institute of Physics. Source

Bhattacharya H.N.,Presidency College | Bull S.,University of Tasmania
Precambrian Research | Year: 2010

The Paleoproterozoic Aravalli basin of Rajasthan, India hosts a number of Pb-Zn sulphide deposits. Various ore genetic models for these deposits are available in the literature, but none of them are backed by comprehensive basin models reconstructed on the basis of sedimentological analysis. In the present work an attempt has been made to propose an actualistic basin model for the Aravalli basin, which was conducive to Pb-Zn sulphide mineralization. The Zawar Mineralized Belt is one of the producing Pb-Zn sulphide belts in the Aravalli basin. The Aravalli sedimentary succession, which is developed on the basement rocks in the Zawar area, is more than 2500 m thick. The whole basin-fill succession, an unconformity-bounded single mega sequence, has been classified into four facies assemblages. The sedimentary facies attributes and their architecture in each facies assemblage advocate in favour of an ensialic rift basin, which experienced repeated down sagging and exhumation. Each foundering event of the rift basin was related to movements along some basin marginal and/or intrabasinal faults, which are manifestation of crustal stretching. Such faults were directly responsible for sediment dispersal in the basin. In this overall tectono-sedimentary frame the ore bearing sediments were deposited as a slope-base fan deposit in deep marine environment. The granitic basement derived sediments that underlie the mineralized horizons are conceived as a source for metals (Pb & B isotopic signatures in galena and tourmaline), and the intrabasinal faults that were active during sedimentation might have acted as conduits for upward transmission of the ore brine. © 2010 Elsevier B.V. All rights reserved. Source

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