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Bishnupur, India

Bhattacharjee B.,Ramananda College | Lu C.-H.,National Taiwan University
Journal of Nanotechnology | Year: 2011

Bright ZnS:Mn 2+ nanoparticles have been synthesized employing microwave irradiation technique and using zinc 2-ethylhexanoate as a novel zinc precursor. A series of samples is obtained by changing the microwave power (from 150W to 500W) to study its effect on the physical properties of the ZnS:Mn2+ nanoparticles. The particle size increases with increasing microwave power for the samples synthesized in the microwave range of 150 W to 300 W. The decrease in particle size for higher microwave power (400W and 500W) can be described as an onset of the secondary nucleation due to the excess energy associated with the higher microwave power. The sample synthesized with microwave power of 300W shows highest luminescence intensity suggesting increase in Mn 2+ luminescence center for the sample synthesized at 300W, as supported by the quantity analysis results. © 2011 Baibaswata Bhattacharjee and Chung-Hsin Lu. Source

Sahu P.,Jadavpur University | Shee S.K.,Midnapore College | Hamada A.S.,University of Oulu | Hamada A.S.,Suez Canal University | And 6 more authors.
Acta Materialia | Year: 2012

The deformation behavior of a Cr-Mn austenitic steel during interrupted low strain rate uniaxial tensile testing at -80°C has been studied using X-ray diffraction (XRD), electron backscatter diffraction and transmission electron microscopy. Continuous γ → → α′ martensite transformation was observed until failure. High dislocation densities were estimated in the austenite phase (∼10 15 m -2), and for the α′-martensite they were even an order of magnitude higher. Dislocation character analysis indicated that increasing deformation gradually changed the dislocation character in the austenite phase to edge type, whereas the dislocations in α′-martensite were predominantly screw type. XRD analyses also revealed significant densities of stacking faults and twins in austenite, which were also seen by transmission electron microscopy. At low strains, the deformation mode in austenite was found to be dislocation glide, with an increasing contribution from twinning, as evidenced by an increasing incidence of ∑3 boundaries at high strains. The deformation mode in α′-martensite was dominated by dislocation slip. © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. Source

Gupta K.,Ramananda College
Research Journal of Chemistry and Environment | Year: 2012

Eight structurally similar dihydroxy and trihydroxyphenolic acids (protocatechuic acid, 3,4-dyhydroxyphenyl acetic acid, hydrocaffeic acid, caffeic acid, gallic acid, 3,4, 5-trihydroxyphenyl acetic acid, 3-(3, 4, 5-trihydroxyphenyl)propanoic acid and 3-(3, 4, 5-trihydroxyphenyl)propenoic acid were investigated for important radical scavenging descriptors like O-H bond dissociation enthalpies (BDE), ionization potentials and, HOMO energies, spin density at radical forming point in the radical forming point by density functional method. It is observed that the type of spacer between the carboxylic acid and the aromatic ring influences scavenging descriptors. Source

Gupta K.,Bhabha Atomic Research Center | Gupta K.,Ramananda College | Ghanty T.K.,Bhabha Atomic Research Center | Ghosh S.K.,Bhabha Atomic Research Center
Physical Chemistry Chemical Physics | Year: 2010

An ab initio investigation of the polarizabilities of the first two excited states of methanol clusters [(CH3OH)n, n = 1-12] has been carried out employing time dependent density functional theory with B3LYP exchange correlation functional using 6-311++G(d,p) and Sadlej basis sets. Good linear correlations have been demonstrated for the first and second excited state polarizabilities as a function of the aggregation number (n) of the methanol clusters. On the contrary, for water clusters the variations of excited state polarizabilities with cluster size are found to be non-monotonic. The variations of the excitation energies and oscillator strengths with n for the first three excited states of methanol clusters and water clusters are also reported. © 2010 the Owner Societies. Source

Chakraborty S.P.,Ramananda College | Roy S.,Vidyasagar University | Pramanik P.,Indian Institute of Technology Kharagpur
Microbial Pathogenesis | Year: 2016

Aims: The present study was aimed to evaluate the in vitro ameliorative effect of nanoconjugated vancomycin (NV) against vancomycin sensitive and resistant strains of Staphylococcus aureus infection-induced oxidative stress in murine peritoneal macrophage. Methods: Peritoneal macrophages from mice were treated with VSSA and VRSA (5 × 106 CFU/mL), VSSA + NV (5-250 μg/ml) and VRSA + NV (5-250 μg/ml) for 18 h, having 3 h interval in culture media; and the superoxide anion generation, lipid peroxidation, protein oxidation, antioxidant enzymes status and glutathione enzymes activity were monitored. Results: The significantly increased free radical generation, lipid peroxidation, protein carbonyls and oxidized glutathione levels were observed in VSSA and VRSA treated group as compared to control group; where as reduced glutathione level, antioxidant enzymes status and glutathione dependent enzymes were decreased significantly. All these changes come near to control in NV treated group in a dose and duration dependent fashion. Among the different doses and duration intervals of NV, maximum ameliorative effect was observed by 100 μg/ml for 12 h treatment which does not produce any damage to the cell. Conclusions: These findings suggest the potential use and beneficial role of nanoconjugated vancomycin as a modulator of S. aureus infection-induced cellular damage in murine peritoneal macrophage. © 2015. Source

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