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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.

Mondal A.,Jadavpur University | Basu R.,Jogamaya Devi College | Das S.,Jadavpur University | Nandy P.,Jadavpur University
Journal of Photochemistry and Photobiology A: Chemistry | Year: 2010

In this paper we report our studies on hybrid photoelectrochemical cell made of thionine and zinc oxide nanoparticles. Nanostructured zinc oxide was synthesized in the laboratory by time and cost effective method. The photoelectrochemical cell yielded voltage of high magnitude (401.5. mV) and efficiency (1.21%) compared to other conventional photoelectrochemical cells. The morphology of the nanostructured zinc oxide was identified by X-ray diffraction and electron microscopy studies. Spectral studies indicated adsorption of the dye molecules on zinc oxide nanoparticles, the reason for efficient absorption of the incident photons. During photoexcitation the thionine molecules and the zinc oxide nanoparticles acted as donor-acceptor cluster which produced photovoltage. © 2010 Elsevier B.V.

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.

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.

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