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Kollam, India

Seven Zn(II) and Cd(II) complexes of ON donor acetone-N(4)- phenylsemicarbazone (HL) have been synthesized and physico-chemically characterized by partial elemental analyses, molar conductance measurements, infrared, electronic and 1H NMR spectral studies. The semicarbazone binds the metal as a neutral bidentate ligand in all the complexes. The crystal structures of acetone-N(4)-phenylsemicarbazone and [Cd(HL)2Cl 2] have been determined by X-ray diffraction studies. The coordination geometry around cadmium(II) in the complex [Cd(HL) 2Cl2] is distorted octahedral. © 2010 Elsevier Ltd. All rights reserved. Source

Mohanty R.B.,NC Autonomous College | Panda T.,SN College
Flora: Morphology, Distribution, Functional Ecology of Plants | Year: 2011

An investigation was carried out to estimate soil respiration rate and its relationship with microbial population in natural tropical forest soil, deforested soil and deforested-and-cultivated soil of Orissa, India. Soil respiration measurements and microbial isolation were performed following standard procedures. Monthly variation of soil respiration was observed to be governed by soil moisture. Considering respiration as a function of microbial population a regression analysis was made. The microfungal population showed positive relationship with the rate of soil respiration. The study revealed that conversion of natural forest led to a reduction of soil microbes and rate of soil respiration. Considering the importance of the microbial component in soil, we conclude that the conversion of natural forests to different land uses leads to the loss of biological stability of the soil. © 2011 Elsevier GmbH. Source

Panda T.,SN College
International Journal of Biodiversity Science, Ecosystems Services and Management | Year: 2010

Seasonal dynamics of soil microfungal populations, their metabolic activity and decomposition of leaf litter were studied in a monoculture plantation of Casuarina equisetifolia L. in coastal sandy belt of Orissa for a period of 2 years (June 2002-May 2004). Fungal succession of litter was also studied. Microbial isolation and soil analysis was performed using standard procedures and decomposition of leaf litter was studied using litter bag technique. Maximum population density was observed in the rainy season followed by winter and lastly summer. Larger microbial populations were encountered in plantation soil compared to barren sand, corresponding with the fluctuation of prevailing temperature, moisture and total organic carbon content. Rates of litter loss and carbon dioxide output followed the same trends as the population density. The annual K value was 0.41. The diversity index varied from 2.87 to 3.71 (Shannon) and 0.356 to 0.885 (Simpson). The similarity index showed that highly decomposed litter (HDL) is more similar to Soil A (barren sand dune) than Soil B (sand dune with monoculture plantation of Casuarina). The introduction of predominantly decomposing microorganisms isolated from samples from the present study could help to increase the nutrient status of these soils. This research will hopefully improve the monitoring and management of decomposing fungi in the study area and highlights their importance in maintaining ecosystem services which could be a valuable tool for better understanding the long-term effects of changes in soil condition of the forest floors in coastal sand dunes of Orissa, India. © 2010 Taylor & Francis. Source

Joshi R.,Bhabha Atomic Research Center | Gangabhagirathi R.,Bhabha Atomic Research Center | Venu S.,SN College | Adhikari S.,Bhabha Atomic Research Center | Mukherjee T.,Bhabha Atomic Research Center
Free Radical Research | Year: 2012

Antioxidant activity of gentisic acid has been studied using fast chemical kinetics and two in vitro models, namely the isolated rat liver mitochondria (RLM) and the human erythrocytes. The presence of gentisic acid (GA) during irradiation significantly reduced the levels of gamma radiation induced damages to lipids and proteins in RLM. Further, GA imparted protection to the human erythrocytes against exposure to gamma radiation. Molecular mechanism of free radical scavenging reactions has been evaluated with the help of rate constants and transients obtained from gentisic acid using pulse radiolysis technique. GA efficiently scavenged hydroxyl radical (k = 1.1 × 10 10 dm 3mol -1s -1) to produce reducing adduct radical (∼76%) and oxidizing phenoxyl radical (∼24%). GA has also scavenged organohaloperoxyl radical (k = 9.3 × 10 7 dm 3 mol -1s -1). Ascorbate has been found to repair phenoxyl radical of GA (k = 1.0 × 10 7 dm 3mol -1s -1). Redox potential value of GA •/GA couple (0.774 V vs NHE) obtained by cyclic voltammetry is less than those of physiologically important oxidants, which supports the observed antioxidant capacity of GA. We, therefore, propose that the antioxidant and radioprotective properties of GA are exerted by its phenoxyl group. Source

Mathew A.M.,National Institute of Technology Calicut | Mathew A.M.,SN College | Predeep P.,National Institute of Technology Calicut
Progress in Organic Coatings | Year: 2012

Electroactive conducting polymer composite coatings of polyaniline (PANI) are electrosynthesized on styrene-butadiene rubber (SBR) coated stainless steel electrode by potentiostatic method using aqueous H 2SO 4 as supporting electrolyte. The protective behaviour of these coatings in different corrosion media (3.5% NaCl and 0.5 M HCl) is investigated using Tafel polarization curves, open circuit potential measurements and electrochemical impedance spectroscopy. The results reveal that SBR/PANI composite coating is much better in corrosion protection than simple PANI coating. The corrosion potential of composite films shifts to more noble values indicating that SBR/PANI composite coating act as an effective corrosion protective layer. © 2011 Elsevier B.V. All Rights Reserved. Source

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