Jogamaya Devi College

Kolkata, India

Jogamaya Devi College

Kolkata, India
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Bhattacharya A.,Jadavpur University | Ghosh R.,Jogamaya Devi College | Chakrabarti B.,Jogamaya Devi College
International Journal of Modern Physics A | Year: 2016

Quark-Anti quark and diquark condensation have been investigated in the framework of the NJL model. The Pauli-Villars regularization scheme have been used for the investigation of meson condensation in three dimension whereas the four dimensional case has been studied using the Schwinger-Dyson equation considering the Hartree approximation. Diquark condensation in three and four dimension have also been studied considering the Pauli-Villars regularization scheme. Using the Fermi momentum (pf) of the particle as cut-off parameter, the gap energy/coherence length for meson condensation (qq) have been investigated whereas for diquark qq the critical gap energy/critical coherence length (the distance over which there would be no diquark condensation) have been extracted. The variation of the coherence length/gap energy with pf have also been investigated. The results are compared with exciting data. Some interesting observations are made. © 2016 World Scientific Publishing Company.

Ghosh R.,Jadavpur University | Bhattacharya A.,Jadavpur University | Chakrabarti B.,Jogamaya Devi College
Acta Physica Polonica B | Year: 2016

The critical values of screening parameters for γ1s and γ2s in Quark- Gluon Plasma (QGP) have been estimated, where the screened potential is represented by an optical potential of type V (r,λ ) = -[ V0+iW0/1+exp((r-R)λ) ]. It has been observed that the critical screening length possesses smaller value indicating a larger suppression compared to the value obtained when the screened potential is represented by real potential. The variation of twoparticle energies of γ1s and γ2s with temperature has also been studied. It has been observed that below T = 0:8 Tc, the two-particle energy remains almost invariant before approaching to deconfinement phase at T = Tc. The results obtained are compared with other existing estimates.

Kar S.,Jadavpur University | Bagchi B.,Indian Central Glass and Ceramic Research Institute | Kundu B.,Indian Institute of Technology Kharagpur | Bhandary S.,Bose Institute of India | And 3 more authors.
Biochimica et Biophysica Acta - General Subjects | Year: 2014

Background Microbial resistance to antibiotics has triggered the development of nanoscale materials as an alternative strategy. To stabilize these particles an inert support is needed. Method Porous nanomullite developed by sol-gel route is loaded with copper and silver nanoparticle by simple adsorption method. These nanocomposites are characterized using XRD, FTIR, TEM, SEM, EDAX and UV-visible spectrophotometer. Antibacterial activity of these nanocomposites against Gram positive and Gram negative bacteria are performed by bactericidal kinetics, flow cytometry and MTT assay. The underlying mechanisms behind the antimicrobial property and cell death are also investigated by EPR spectroscopy, intracellular ROS measurement and β-galactosidase assay. The cytocompatibility of the nanocomposites is investigated by cell viability (MTT), proliferation (Alamar blue) and wound healing assay of mammalian fibroblast cell line. Results Nanocomposites show a fairly uniform distribution of metal nanoparticle within mullite matrix. They show excellent antibacterial activity. Metal ions/nanoparticle is found to be released from the materials (CM and SM). Treated cells manifested high intracellular oxidative stress and β-galactosidase activity in the growth medium. The effect of nanocomposites on mammalian cell line depends on exposure time and concentration. The scratch assay shows normal cell migration with respect to control. Conclusion The fabricated nanoparticles possess diverse antimicrobial mechanism and exhibit good cytocompatibility along with wound healing characteristics in mouse fibroblast cell line (L929). General significance The newly synthesized materials are promising candidates for the development of antimicrobial ceramic coatings for biomedical devices and therapeutic applications. © 2014 Elsevier B.V.

Mondal A.,Jadavpur University | Basu R.,Jogamaya Devi College | Das S.,Jadavpur University | Nandy P.,Jadavpur University
Journal of Nanoparticle Research | Year: 2011

Nowadays an increasing application of nanotechnology in different fields has arisen an extensive debate about the effect of the engineered nanoparticles on environment. Phytotoxicity of nanoparticles has come into limelight in the last few years. However, very few studies have been done so far on the beneficial aspects of nanoparticles on plants. In this article, we report the beneficial effect of multi-walled carbon nanotubes (MWCNTs) having diameter of ∼30 nm on Brassica juncea (mustard) seeds. Measurements of germination rate, T 50 (time taken for 50% germination), shoot and root growth have shown encouraging results using low concentration of oxidized MWCNT (OMWCNT) treated seeds as compared to non-oxidized as well as high concentration OMWCNT treated seeds. For toxicity study we measured the germination index and relative root elongation, while conductivity test and infra-red spectra were also performed to study the overall effect of oxidized and non-oxidized nanotubes on mustard seeds and seedlings. © 2011 Springer Science+Business Media B.V.

Ghosh G.,Presidency University of India | Ghosh B.,Jogamaya Devi College | Mukhopadhyay J.,Presidency University of India
Geological Society Memoir | Year: 2015

The Singhbhum Craton preserves large low-grade tracts of an extensive stratigraphic period in the Precambrian and therefore is of prime importance for studying the Earth's early evolutionary processes. An early (c. 3.1 Ga) crustal stabilization followed by a long period (c. 500 Ma) of high freeboard conditions has been postulated from the terrane in recent times. Tectonostratigraphic analyses of the supracrustal successions, carried out in the present study, from the west-northwestern margin of the Singhbhum Granite body in the craton identify a hitherto undetected Mesoarchaean shelf sequence among these supracrustal successions. In contrast to current thinking, the observations imply immediate development of a passive margin setting following the craton's early stabilization. The cratonic margin later succumbed to a major compression, resulting in successive emplacement of thrust sheets from the northern hinterland side that produced an intermingling of thrust slices of basement rocks and the deformed shelf and rift sequences. This later compressive episode not only involved a part of the Mesoproterozoic Kolhan Basin, but its effects are also manifest as a second deformation throughout the western Iron Ore Group belt. Involvement of the Kolhan Group in the deformation milieu constrains the timing of this orogeny to the Grenvillian (c. 1.0 Ga). © 2015 The Geological Society of London.

Bagchi B.,Jadavpur University | Dey S.,Indian Institute of Chemical Technology | Bhandary S.,Jadavpur University | Das S.,Jadavpur University | And 3 more authors.
Materials Science and Engineering C | Year: 2012

A mullite based antimicrobial ceramic composite has been developed by simple adsorption of copper nano particle suspension. The physico-chemical properties of samples were characterized by different instruments which showed that the composite is well crystalline with homogeneous distribution of copper nanoparticles on the surface. Antimicrobial study was performed by plate count technique which showed > 99% mortality for all the bacterial species studied after 24 h of incubation. Minimum inhibitory concentration (MIC) values determined by batch culture process showed considerably low values (in terms of copper content) indicating that mullite matrix plays a role in enhancing the antimicrobial efficacy of the composite. Biocompatibility studies on human cancer cell lines indicated that the composite had negligible toxicity below 100 μg/mL of Cu content. Thus the composite can be suitable for developing antimicrobial ceramic wares and therapeutic purposes like treatment of variety of microbial infections. © 2012 Elsevier B.V. All rights reserved.

Sultana P.,Jadavpur University | Das S.,Jadavpur University | Bhattacharya A.,West Bengal State University | Basu R.,Jogamaya Devi College | Nandy P.,The Interdisciplinary Center
Materials Science and Engineering C | Year: 2012

The increasing accumulation of fly ash from thermal power plants poses a major problem to the environment. The present work reflects the novel utilization of this profusely available industrial waste in the form of an antibacterial hard ceramic material by treating fly ash with ferric oxide (Fe 2O 3) and titania (TiO 2) during sintering process at 1600 °C. The developed material shows more than 90% bacterial reduction against both Gram-positive and Gram-negative bacteria. The mechanism of their antibacterial action was studied by transmission electron microscopy (TEM) image analysis of the bacterial cross-section. The developed ceramic material acquires hardness due to the enhancement of the natural mullite content in the matrix. The mullite content and the crystallinity of mullite have shown their increasing trend with increasing concentration of the metal oxide during sintering process. A maximum of ~ 37% increase in mullite was obtained for 7% w/w Fe 2O 3 and TiO 2. Metal oxide lowered the activation energy of the reaction and enhanced the reaction rate of alumina (Al 2O 3)-silica (SiO 2) to form mullite which increases the hardness. The study highlights novel utilization of fly ash as a hard ceramic antibacterial product (bioceramics) for both structural and hygiene applications in an eco-friendly way. © 2012 Elsevier B.V.

Bagchi B.,Jadavpur University | Das S.,Jadavpur University | Bhattacharya A.,West Bengal State University | Basu R.,Jogamaya Devi College | Nandy P.,Jadavpur University
Applied Clay Science | Year: 2010

Mullite phase development in Indian kaolinites was investigated in the presence of vanadium pentoxide and characterized by X-ray diffraction, FESEM and FTIR spectroscopy. The addition of V2O5 markedly enhanced the amount of mullite phase and also lowered the mullitization temperature. The mullite phase was highly crystalline with rod shaped particles of average dimensions of 350-500 nm and 70-100 nm. A maximum of 27% increase in mullite phase was obtained at 7% (by mass) V2O5 after sintering at 1000 °C for 2 h. © 2009 Elsevier B.V. All rights reserved.

Bala N.,Jadavpur University | Saha S.,Jadavpur University | Chakraborty M.,Jadavpur University | Maiti M.,Jadavpur University | And 3 more authors.
RSC Advances | Year: 2015

Zinc oxide (ZnO) nanoparticles (NPs) have been synthesized using Hibiscus subdariffa leaf extract. Temperature dependent synthesis and particle growth have been studied. Formation of NPs was confirmed by UV-visible (UV-VIS) spectroscopy, Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). Electron microscopy has been used to study the morphology and size distribution of the synthesized particles. The synthesized ZnO nanoparticles as potential anti-bacterial agents have been studied on Escherichia coli and Staphylococcus aureus. Another study has indicated that small sized ZnO NPs, stabilized by plant metabolites had better anti-diabetic effect on streptozotocin (STZ) induced diabetic mice than that of large sized ZnO particles. It has also been observed by enzyme linked immunosorbent assay (ELISA) and real time polymerase chain reaction (RT-PCR) that ZnO can induce the function of Th1, Th2 cells and expressions of insulin receptors and other genes of the pancreas associated with diabetes. © The Royal Society of Chemistry 2015.

Mondal A.,Jadavpur University | Basu R.,Jogamaya Devi College | Das S.,Jadavpur University | Nandy P.,Jadavpur University
Energy | Year: 2010

The quest for alternative energy sources has stimulated interest in several new materials. Using an aqueous suspension of zinc oxide nanoparticles in specially-designed electrochemical cells we have observed significant voltage (maximum 498.0 mV) and storage capacity (∼60 h) upon thermal excitation. Voltage increased gradually with increasing temperature. The cells exhibited reasonable energy conversion efficiency (maximum 1.05%). Moreover, increases in efficiency and storage duration were observed with the insertion of a planar lipid membrane (PLM) within the electrochemical cell, since the hydrophobic barrier of the lipid membrane hindered back recombination of the charges produced by thermal excitation. The novelty of the cells lies in the fact that voltage was generated by utilizing the heat energy of solar radiation, as opposed to the light quanta of the solar influx used in conventional photovoltaic cells. © 2010 Elsevier Ltd. All rights reserved.

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