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North Guwāhāti, India

Kar T.K.,Bengal Engineering and Science University | Chattopadhyay S.K.,Sree Chaitanya College
Comptes Rendus - Biologies | Year: 2010

Within the framework of a general equilibrium model we study the long-run dynamics of a prey-predator model in the presence of an alternative prey. Our results show that sustainability, i.e. a positive value of the population in the long run, essentially depends on individual harvesting efforts and digesting factors relative to alternative prey. A detailed bifurcation analysis evidences the richness of possible long-run dynamics. Our model clearly shows that the role of an alternative prey must be taken into consideration when studying prey-predator dynamics. © 2010 Académie des sciences. Published by Elsevier Masson SAS. All rights reserved. Source

Gayen K.S.,University of Calcutta | Sengupta T.,University of Calcutta | Saima Y.,University of Calcutta | Das A.,University of Calcutta | And 2 more authors.
Green Chemistry | Year: 2012

Small Cu(0)-nanoparticles (NPs) are fabricated utilizing CuSO 4·5H2O, surfactant (SDS) and ascorbic acid in aqueous medium. Its outstanding catalytic activity under low catalyst loading is developed toward reductive cleavage of isoxazoline, carbonyl azide and domino cyclization to furnish valuable 2-hydroxy-4-keto esters, primary amides and a new class of heterocycle, 4-hydroxy-2-pyrroline-5-one. This journal is © The Royal Society of Chemistry. Source

Das M.,Sree Chaitanya College | Pal S.,Human Genetic Engineering Research Center | Ghosh A.,Visva Bharati University
Journal of Cardiovascular Disease Research | Year: 2012

Background: Our objective was to test the association between familial risk of type 2 diabetes mellitus (T2DM) and the prevalence of metabolic syndrome (MS) in adult Asian Indians. Materials and Methods: A total of 448 adult (>30 years) individuals (257 males and 191 females) participated in the study. Familial risk of T2DM was classified into three groups viz., 1=both parents affected; 2=parent and/or siblings affected and 3=none or no family history for T2DM. Anthropometric measures, blood pressures, fasting blood glucose and metabolic profiles were studied using standard techniques. MS was defined accordingly. The prevalence of MS phenotypes was estimated and compared among the three familial risk strata. Results: Individuals with a history of both parents affected from diabetes had significantly higher (P<0.001) body mass index (BMI), waist circumference (WC), waist-hip ratio (WHR), systolic blood pressure (SBP), diastolic blood pressure (DBP) and fasting blood glucose (FBG; P=0.035) than individuals having no family history of T2DM. Significant difference was also noticed between individuals with and without MS according to the family history of diabetes (P<0.001). Differences were evident between individuals who fulfilled all the MS criteria (P=0.001) and individuals with only one or two criteria (phenotypes) according to family history of T2DM. Conclusion: Family history of T2DM had significant effect on individuals with MS as compared to their counterparts (individuals having no family history of T2DM). It therefore seems reasonable to argue that family history of T2DM could be useful as a predictive tool for early diagnosis and prevention of MS in Asian Indian population. Source

Dalapati S.,University of Calcutta | Alam M.A.,Aliah University | Jana S.,University of Calcutta | Karmakar S.,Sree Chaitanya College | Guchhait N.,University of Calcutta
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2013

Test paper coated with Schiff base [(N,N/-bis(5-nitro- salicylidene)hydrazine] receptor 1 (host) can selectively detect fluoride and acetate ions (guest) by developing yellow color which can be detected by naked-eye both in aqueous-acetonitrile solution and in solid supported test kit. UV-vis spectral analysis shows that the absorption peaks at 288 and 345 nm of receptor 1 gradually decrease its initial intensity and new red shifted absorption bands at 397 nm and 455 nm gradually appear upon addition of increasing amount of F- and AcO- ions over several tested anions such as H2PO4-, Cl-, Br-, I-, NO3-, NO2-, HSO4-, HSO3-, and ClO4- in aqueous-acetonitrile solvent. The colorimetric test results and UV-vis spectral analysis are in well agreement with 1H NMR titration results in d6-DMSO solvent. The receptor 1 forms 1:2 stable complexes with F- and AcO- ions. However, similar kind of observation obtained from UV-vis titrations in presence of AcOH corresponds to 1:1 complexation ratio indicating the formation of H-bonding interaction between the receptor and anions (F- and AcO- ions). So, the observed 1:2 complexation ratio can only be explained on the basis of deprotonation (∼1 eqv.) and H-bonding (∼1 eqv.) interactions [1]. The ratiometric analysis of host-guest complexes corroborates well with the proposed theoretical model optimization at Density Functional Theory (DFT) level. © 2012 Elsevier B.V. All rights reserved. Source

Panigrahi D.,Sree Chaitanya College | Panigrahi D.,Jadavpur University
International Journal of Modern Physics D | Year: 2015

The thermodynamical behavior of the variable Chaplygin gas (VCG) model is studied, using an equation-of-state (EoS) like P = - B/ρ, where B = B0V-n/3. Here B0 is a positive universal constant, n is also a constant and V is the volume of the fluid. From the consideration of thermodynamic stability, it is seen that only if the values of n are allowed to be negative, then (∂P/∂V)S < 0 throughout the evolution. Again thermal capacity at constant volume cV shows positive expression. Using the best fit value of n = -3.4 as previously found by Guo and Zhang (Phys. Lett. B. 645 (2007) 326) gives that the fluid is thermodynamically stable throughout the evolution. The effective EoS for the special case of n = 0 goes to Λ Cold Dark Matter (ΛCDM) model. Again for n < 0, it favors phantom-like cosmology which is in agreement with the current SNe Ia constraints like VCG model. The deceleration parameter is also studied in the context of thermodynamics and the analysis shows that the flip occurs for the value of n < 4. Finally, the thermal EoS is discussed which is an explicit function of temperature only. It is also observed that the third law of thermodynamics is satisfied in this model. As expected, the volume increases as temperature falls during adiabatic expansions. In this case, for T → 0, the thermal EoS reduces to (- 1 + n/6), which is identical with the EoS for the case of large volume. © 2015 World Scientific Publishing Company. Source

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