Basanti Devi College

Kolkata, India

Basanti Devi College

Kolkata, India

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Chatterjee S.,Basanti Devi College | Roy B.,University of Calcutta | Roy D.,University of Calcutta | Banerjee R.,University of Calcutta
Polymer Degradation and Stability | Year: 2010

Extruded low-density polyethylene (LDPE) films commonly available in the market as 20-micron thick carrier bags were autoclaved, overlaid on nutrient agar plates and inoculated with BP/SU1 strain of Staphylococcus epidermis. The nutrient agar plate showed growth of the organism within two to three days. The polymer film supporting the growth of the organism showed pore formation as recorded by SEM analysis. The growth of BP/SU1 is supported by the presence of shredded LDPE as its only carbon source in inorganic salt minimal nutrient medium. The organism survives even after three months of inoculation and this is accompanied by gradual breakdown of the size of the shredded plastic as seen by light scattering. The cell-free supernatant of the organism, grown with the help of shredded plastic shows the presence of the over expressed proteins with approximate molecular weight of about 55 kDa and 35 kDa, through SDS-PAGE analysis. © 2009 Elsevier Ltd.


Khan S.,Jadavpur University | Roy S.,Basanti Devi College | Roy R.,Jadavpur University | Ghatak A.,Jadavpur University | And 2 more authors.
Tetrahedron Letters | Year: 2014

Differently substituted cyclopropylcarbinols underwent ring cleavage with easily accessible cyanuric chloride-N,N-dimethylformamide adduct to produce homoallylic chlorides or dienes depending on the nature and location of the substituents. A mechanistic explanation of the aforesaid observations has been provided. A promising antioxidant compound was prepared following this protocol and studied against Fenton's reagent. This methodology was utilized to construct hitherto unreported vinylcyclopropane frameworks bearing homoallylic chloride and diene moieties. © 2014 Elsevier Ltd. All rights reserved.


Roy S.,Basanti Devi College | Bhar S.,Jadavpur University
Green Chemistry Letters and Reviews | Year: 2010

Synthesis of structurally varied β-arylvinyl bromides has been accomplished in an eco-friendly "On-water" condition through bromodecarboxylation reaction of appropriately substituted cinnamic acids with potassium bromide using hydrogen peroxide as oxidant and sodium tungstate as catalyst.Salient mechanistic features have also been highlighted. © 2010 Taylor & Francis.


Jain V.,National Institute of Oceanography of India | Shankar D.,National Institute of Oceanography of India | Vinayachandran P.N.,Indian Institute of Science | Kankonkar A.,National Institute of Oceanography of India | And 18 more authors.
Climate Dynamics | Year: 2016

The high-salinity water masses that originate in the North Indian Ocean are Arabian Sea High-Salinity Water (ASHSW), Persian Gulf Water (PGW), and Red Sea Water (RSW). Among them, only ASHSW has been shown to exist in the Bay of Bengal. We use CTD data from recent cruises to show that PGW and RSW also exist in the bay. The presence of RSW is marked by a deviation of the salinity vertical profile from a fitted curve at depths ranging from 500 to 1000 m; this deviation, though small (of the order of ~0.005 psu and therefore comparable to the CTD accuracy of 0.003 psu), is an order of magnitude larger than the ~0.0003 psu fluctuations associated with the background turbulence or instrument noise in this depth regime, allowing us to infer the existence of RSW throughout the bay. PGW is marked by the presence of a salinity maximum at 200–450 m; in the southwestern bay, PGW can be distinguished from the salinity maximum due to ASHSW because of the intervening Arabian Sea Salinity Minimum. This salinity minimum and the maximum associated with ASHSW disappear east and north of the south-central bay (85°E, 8°N) owing to mixing between the fresher surface waters that are native to the bay (Bay of Bengal Water or BBW) with the high-salinity ASHSW. Hence, ASHSW is not seen as a distinct water mass in the northern and eastern bay and the maximum salinity over most of the bay is associated with PGW. The surface water over most of the bay is therefore a mixture of ASHSW and the low-salinity BBW. As a corollary, we can also infer that the weak oxygen peak seen within the oxygen-minimum zone in the bay at a depth of 250–400 m is associated with PGW. The hydrographic data also show that these three high-salinity water masses are advected into the bay by the Summer Monsoon Current, which is seen to be a deep current extending to 1000 m. These deep currents extend into the northern bay as well, providing a mechanism for spreading ASHSW, PGW, and RSW throughout the bay. © 2016 Springer-Verlag Berlin Heidelberg


Chaudhuri S.K.,Khorop High School | Roy S.,Basanti Devi College | Bhar S.,Jadavpur University
Beilstein Journal of Organic Chemistry | Year: 2012

An efficient solvent-free protocol for regioselective bromination of substituted coumarins has been developed by using dioxane dibromide as the solid brominating agent. The efficacy of the solvent-free protocol has been established. The effects of the electronic nature and location of the substituents on the outcome of the reaction have been rationalized with a proposed mechanism. © 2012 Chaudhuri et al.


Chatterjee M.,Basanti Devi College | Chatterjee M.,Jadavpur University | Shankar D.,National Institute of Oceanography of India | Sen G.K.,Jadavpur University | And 21 more authors.
Journal of Earth System Science | Year: 2013

Situated in the eastern coastal state of West Bengal, the Sundarbans Estuarine System (SES) is India's largest monsoonal, macro-tidal delta-front estuarine system. It comprises the southernmost part of the Indian portion of the Ganga-Brahmaputra delta bordering the Bay of Bengal. The Sundarbans Estuar-ine Programme (SEP), conducted during 18-21 March 2011 (the Equinoctial Spring Phase), was the first comprehensive observational programme undertaken for the systematic monitoring of the tides within the SES. The 30 observation stations, spread over more than 3600 km2, covered the seven inner estuaries of the SES (the Saptamukhi, Thakuran, Matla, Bidya, Gomdi, Harinbhanga, and Raimangal) and represented a wide range of estuarine and environmental conditions. At all stations, tidal water levels (every 15 minutes), salinity, water and air temperatures (hourly) were measured over the six tidal cycles. We report the observed spatio-temporal variations of the tidal water level. The predominantly semi-diurnal tides were observed to amplify northwards along each estuary, with the highest amplification observed at Canning, situated about 98 km north of the seaface on the Matla. The first definite sign of decay of the tide was observed only at Sahebkhali on the Raimangal, 108 km north of the seaface. The degree and rates of amplification of the tide over the various estuarine stretches were not uniform and followed a complex pattern. A least-squares harmonic analysis of the data performed with eight constituent bands showed that the amplitude of the semi-diurnal band was an order of magnitude higher than that of the other bands and it doubled from mouth to head. The diurnal band showed no such amplification, but the amplitude of the 6-hourly and 4-hourly bands increased headward by a factor of over 4. Tide curves for several stations displayed a tendency for the formation of double peaks at both high water (HW) and low water (LW). One reason for these double-peaks was the HW/LW stands of the tide observed at these stations. During a stand, the water level changes imperceptibly around high tide and low tide. The existence of a stand at most locations is a key new finding of the SEP. We present an objective criterion for identifying if a stand occurs at a station and show that the water level changed imperceptibly over durations ranging from 30 minutes to 2 hours during the tidal stands in the SES. The tidal duration asymmetry observed at all stations was modified by the stand. Flow-dominant asymmetry was observed at most locations, with ebb-dominant asymmetry being observed at a few locations over some tidal cycles. The tidal asymmetry and stand have implications for human activity in the Sundarbans. © Indian Academy of Sciences.


Sen G.K.,Jadavpur University | Das M.,Jadavpur University | Chatterjee M.,Basanti Devi College
Ecology, Environment and Conservation | Year: 2010

The Regional Ocean Model System (ROMS) driven by NCEP reanalyzed forcing fields together with QuickScatt wind observations, has been used to study evolution of surges in the Northern Bay of Bengal (adjacent to West Bengal Coast of India ) due to Cyclone AILA ( 24-25 May 2009 ). The model was, very consistent and able to simulate basic sea level variation very well. A comparison with observation at aparticular location (near Digha) was also provided. The results show that ROMS model is robust enough to reproduce surge impact very consistently. Copyright © Enviromedia.

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