Showing papers by "Bharathiar University published in 2003"

Effect of dried fruits of Solanum nigrum LINN against CCl4-induced hepatic damage in rats.

Abstract: Ethanol extract of Solanum nigrum LINN was investigated for its hepatoprotective activity against CCl4-induced hepatic damage in rats. The ethanol extract showed remarkable hepatoprotective activity. The activity was evaluated using biochemical parameters such as serum aspartate amino transferase (AST), alanine amino transferase (ALT), alkaline phosphatase (ALP) and total bilirubin. The histopathological changes of liver sample in treated animals were compared with respect to control.

Dielectric properties of Cd0.6Zn0.4Te thin films

Abstract: Cd0.6Zn0.4Te thin films of different thicknesses were prepared by the thermal evaporation technique onto well-cleaned Corning glass substrates. The dielectric properties of Al/Cd0.6Zn0.4Te/Al sandwich structures were studied in the frequency range 50 Hz–4 MHz and in the temperature range 300–420 K. The effect of thickness on the net dielectric constant was studied in detail. The bulk dielectric constant was calculated as 13.5, which is consistent with the value of 11.5–8.2 measured at 1 MHz for the films of different thickness varying between 120 and 850 nm. The relaxation phenomenon present in the films is due to the presence of grains and grain boundaries across the film thickness. The relaxation times decrease with increasing measuring temperatures, suggesting that the net relaxation phenomenon is associated with the charge carrier transport mechanism. The grain boundary activation energies, calculated from the spectroscopic plot, vary between 0.61 and 0.53 eV. The variation of conductivity as a function of temperature and frequency reveals non-adiabatic hopping of charge carriers between impurity sites/localized states and the activation energies are found to vary between 0.28 and 0.11 eV. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Microbial decolorization of azo dyes and dye industry effluent by Fomes lividus

Abstract: The white rot fungus, Fomes lividus, was isolated from the logs of Shorea robusta in the Western Ghats region of Tamil Nadu, India. The fungus was tested for decolorization of azo dyes such as orange G (50 μM) congo red (50 μM) amido black 10B (25 μM) and also for colour removal from dye industry effluents. The results revealed that the fungus could remove only 30.8% of orange G in the synthetic solution, whereas congo red and amido black 10B were removed by 74.0 and 98.9% respectively. A dye industry effluent was treated by the fungus in batch and continuous mode. In batch mode treatment, a maximum decolorization of 84.4% was achieved on day 4, and in continuous mode a maximum decolorization of 37.5% was obtained on day 5. The colour removal by the basidiomycete fungus might be due to adsorption of the dyes to the mycelial surface and metabolic breakdown. These results suggested that the batch mode treatment of Fomes lividus is one of the most efficient ways for colour removal in dye industry effluents.

Effect of Gymnema montanum leaves on serum and tissue lipids in alloxan diabetic rats.

Abstract: The effect of Gymnema montanum leaves on alloxaninduced hyperlipidemia was studied in male Wistar rats. Ethanolic extract of G. montanum leaves was administered orally and different doses of the extract on blood glucose, serum and tissue lipids, hexokinase, glucose-6-phosphatase, thiobarbituric acid–reactive substances (TBARS), hydroperoxides, and glutathione in alloxan-induced diabetic rats were studied. G. montanum leaf extract (GLEt) at doses of 50, 100, 200 mg/kg body weight for 3 weeks suppressed the elevated blood glucose and lipid levels in diabetic rats. GLEt at 200 mg/kg body weight was found to be comparable to glibenclamide, a reference drug. These data indicate that G. montanum represents an effective antihyperglycemic and antihyperlipidemic adjunct for the treatment of diabetes and a potential source of discovery of new orally active agent for future therapy.

Pulsed laser deposited vanadium oxide thin films for uncooled infrared detectors

Abstract: Vanadium oxide thin films were deposited by pulsed laser deposition (PLD) technique using V 2O5 as target. A new deposition parameter has been extracted to deposit vanadium oxide thin films at room temperature for uncooled microbolometers. Temperature coefficient of resistance (TCR) is one of the vital bolometric parameters, which influences the performance of the uncooled microbolometer infrared detectors was determined. The TCR values of vanadium oxide films deposited by PLD at room temperature are coinciding with the reported TCR values of successful vanadium oxide thin films deposited at elevated temperatures by other techniques for bolometric applications. We further investigated the influence of laser fluence on the electrical property of the vanadium oxide films. © 2003 Elsevier B.V. All rights reserved.

Biodiversity in Indian Underexploited/Tribal Pulses

Abstract: Pulses are an important source of proteins to the vegetarian and socio-economically weaker sections of the population. With rapid increase in population coupled with stagnation in pulses production at around 12 to 14 million tonnes, the per capita availability of protein has decreased causing Protein-Energy-Malnutrition (PEM) especially among children below the age of five years in India. This has necessitated exploration of alternate sources of protein to bridge the gap for protein requirement of the various sections of vegetarian population. In this context, alternate sources like untraditional legumes (underexploited/tribal pulses) assume significance. Therefore it is time to understand their biodiversity with a view to exploit such genetic resources for additional supply of plant protein, so that they can augment the availability of protein from conventional pulse crops in India. Around 40 legumes belonging to the genera, Abrus, Acacia, Alysicarpus,Atylosia, Bauhinia, Canavalia, Cassia, Dolichos,Entada, Erythrina, Indigofera, Lens, Mucuna,Parkia, Parkinsonia, Phaseolus, Pongamia, Prosopis,Sesbania, Tamarindus, Vicia, Vigna and Xylia are known to be consumed by as many as 550 tribal communities in India who account for 67.76 million of total Indian population. Besides there are another 10 underexploited/little known legumes, which have not been exploited to the extent they deserve. The importance of Indigenous Knowledge (IK) including the traditional medicinal properties of these wild legumes have been enumerated. The authors’ team of workers have gathered 192 germplasm (accessions) of wild legumes including 45 tribal pulses from different agroclaimatic regions in India. Marked genetic variation among the germplasm/varieties of several tribal pulses at the time of collection and evaluation for agrobotanical characters have been recorded. The genetic erosion of germplasm of tribal pulses, such as Entada scandense, Mucuna monosperma, M. gigantea, Atylosia goensis,Bauhinia vahlii, Xylia xylocarpa, Parkia roxburghii, Vigna radiata var. sublobata, V. mungo var. silvestris and V grandis, has been noticed. Several germplasm conservation strategies and their utility in this context have been stressed. Chemical investigations on levels of crude protein and crude lipid also have revealed the existence of genetic diversity not only among different varieties but also among different germplasm of the same species. Several germplasm/varieties/species such as Atylosia goensis, Canavalia ensiformis, C. gladiata, Erythrina indica, Indigofera linifolia, Lens esculenta, Mucuna spp., Psophocarpus spp., Pongamia pinnata, Phaseolus lunatus, Sesbania bispinosa, Vicia faba, Vigna trilobata and Xylia xylocarpa possess 20–80% (w/w) more crude protein compared to the conventional pulses. Similarly several germplasm/varieties/species like Alysicarpus rugosus, Bauhinia spp., Cassia spp., Entada scandense, Erythrina indica, Mucuna spp., Parkia roxburghii, Pongamia pinnata, Prosopis chilensis, Psophocarpus spp., Tamarindus indica and Xylia xylocarpa contain high levels of crude lipid (10–30%, w/w). Human nutrition requires a balanced source of essential amino acids. Generally seed proteins of several legumes are deficient in sulfur — containing amino acids, cysteine and methionine. Exceptionally the seed proteins of Alysicarpus rugosus, Indigofera linifolia and Tamarindus indica contain sulfur containing amino acids more than FAO/WHO (1991) requirement pattern. Similarly seed proteins of certain varieties/germplasm of tribal pulses like Abrus precatorius, Acacia leucophloea, A. nilotica, Bauhinia malabarica, Canavalia gladiata, Cassia laevigata, Entada scandens, Indigofera linifolia, Mucuna pruriens var. pruriens, M. pruriens var. utilis, Parkia roxburghii, Phaseolus lunatus, Prosopis chilensis, Parkinsonia aculeata, Pongamia pinnata, Vigna aconitifolia, V. capensis, V. sesquipedalis, V. sinensis, V. sublobata, V. umbellata, V. vexillata and Xylia xylocarpa contain tryptophan more than FAO/WHO (1991) requirement pattern. The germplasm of untraditional pulses such as Canavalia ensiformis, C. gladiata, Mucuna pruriens var. pruriens, M. pruriens var. utilis and Psophocarpus tetragonolobus have been advocated for large scale cultivation and consumption as alternate and additional sources of plant protein after toxicological evaluation and technological processing.

Incidence of haemolysin-positive and drug-resistant Aeromonas hydrophila in freshly caught finfish and prawn collected from major commercial fishes of coastal South India

Abstract: The incidence of Aeromonas hydrophila in freshly caught finfish and prawns from four major commercial fish landing sites of coastal South India was studied for a period of one year. Among 514 analysed samples of seafood (410 finfish and 104 prawn), 37% of them (37.3% of finfish and 35.6% of prawn) were contaminated with A. hydrophila. A total of 255 strains of A. hydrophila were isolated. Of the total isolates, about 78.4% of them were producers of haemolysin. All strains were resistant to bacitracin and all were sensitive to chloramphenicol. The results indicate that the strains originated from high-risk sources. The presence of A. hydrophila is an indication of marine contamination. The increasing presence of haemolysin-producing multiple drug-resistant A. hydrophila in fish and prawn may become a potential human health hazard.

Understanding geophagy in animals: standard procedures for sampling soils

Abstract: Geophagy or soil ingestion is a multidisciplinary phenomenon that has attracted the attention of many researchers in recent years; who have sought to understand why a large number of animals consume natural earths. To find out why animals ingest soils, it is of paramount importance to establish standard methods to analyze comestible soil. Researchers have used different methods to examine soils ingested by animals, often with incomplete or inconclusive results. To make meaningful comparisons among studies, it is necessary to perfect research designs and establish standard methods to evaluate and analyze geophagy in animals.

The potential of bacterial isolates for emulsification with a range of hydrocarbons

Abstract: A study was undertaken to investigate the distribution of biosurfactant producing and crude oil degrading bacteria in the oil contaminated environment. This research revealed that hydrocarbon contaminated sites are the potent sources for oil degraders. Among 32 oil degrading bacteria isolated from ten different oil contaminated sites of gasoline and diesel fuel stations, 80% exhibited biosurfactant production. The quantity and emulsification activity of the biosurfactants varied. Pseudomonas sp. DS10-129 produced a maximum of 7.5 +/- 0.4 g/l of biosurfactant with a corresponding reduction in surface tension from 68 mN/m to 29.4 +/- 0.7 mN/m at 84 h incubation. The isolates Micrococcus sp. GS2-22, Bacillus sp. DS6-86, Corynebacterium sp. GS5-66, Flavobacterium sp. DS5-73, Pseudomonas sp. DS10-129, Pseudomonas sp. DS9-119 and Acinetobacter sp. DS5-74 emulsified xylene, benzene, n-hexane, Bombay High crude oil, kerosene, gasoline, diesel fuel and olive oil. The first five of the above isolates had the highest emulsification activity and crude oil degradation ability and were selected for the preparation of a mixed bacterial consortium, which was also an efficient biosurfactant producing oil emulsifying and degrading culture. During this study, biosurfactant production and emulsification activity were detected in Moraxella sp., Flavobacterium sp. and in a mixed bacterial consortium, which have not been reported before.

Optical constants of DC magnetron sputtered titanium dioxide thin films measured by spectroscopic ellipsometry

Abstract: Optical constants of DC magnetron sputtered $TiO_2$ thin film have been determined by Spectroscopic Ellipsometry in the photon energy range 1.2 to 5.5 eV at room temperature. The measured dielectric-function spectra reveal distinct structures at energies of the E1, E1 + \bigtriangleup 1 and E2 critical points are due to interband transitions. The root mean square roughness of the magnetron sputtered $TiO_2$ thin films evaluated by ex-situ atomic force microscopy is 5.8 nm. The Dielectric constant values were found to be substantially lower than those for the bulk $TiO_2$. The dielectric related Optical constants, such as the refractive index, extinction coefficient, absorption coefficient and normal incidence of reflectivity determined from the spectroscopic ellipsometry data are presented and analyzed. The optical constants of the films were also determined using the optical transmittance measurements and the results were discussed.

Mycorrhiza of plants in different vegetation types in tropical ecosystems of Xishuangbanna, southwest China.

Abstract: We examined plants growing in four tropical vegetation types (primary forest, secondary forest, limestone forest and a slash and burn field) in Xishuangbanna, southwest China for mycorrhizal associations. Of the 103 plant species examined (belonging to 47 families), 81 had arbuscular mycorrhizal (AM) associations, while three species possessed orchid mycorrhiza. AM colonization levels ranged between 6% and 91% and spore numbers ranged between 1.36 spores and 25.71 spores per 10 g soil. Mean AM colonization level was higher in primary and secondary forest species than in plant species from limestone forests and a slash and burn field. In contrast, mean AM fungal spore numbers of the primary and limestone forest were lower than in the secondary forest or the slash and burn field. AM fungal spores belonging to Glomus and Acaulospora were the most frequent in soils of Xishuangbanna. AM fungal colonization and spore numbers were significantly correlated to each other and were significantly influenced by vegetation type.

Dielectric and electric modulus properties of vacuum evaporated Cd0.8Zn0.2Te thin films

Abstract: Cd 0.8 Zn 0.2 Te thin films were prepared by vacuum evaporation technique. The variation of dielectric constant and dielectric loss tangent were found to depend on temperature and frequency. Impedance and electric modulus formalisms were employed in order to gain an insight into the microstructural details of films. A comprehensive study on the relaxation mechanism revealed that the presence of grain and grain boundaries across the film thickness were the basic relaxation phenomenon. The activation energies calculated from the loss tangent and spectroscopic modulus mechanism were found to vary between 1.24 and 0.91 eV for the film of thicknesses 230–800 nm. The frequency analysis of modulus properties showed a distribution of relaxation times. Conductivity plots against frequency at higher frequency suggested the response obeying the universal power law. The role of bulk and grain boundary in the overall conduction process has been discussed with realistic justification. The defect density varies between 2 and 5×10 15 eV −1 m −2 for the films of thicknesses studied.

Study of a pulsed laser deposited vanadium oxide based microbolometer array

Abstract: A 2D 10-element test microbolometer array was fabricated without an air-gap thermal isolation structure. The microbolometer uses vanadium oxide film deposited by pulsed laser deposition at room temperature as the infrared (IR) sensitive layer. The IR response of the uncooled microbolometer was evaluated in the spectral region of 8–15 μm. The detectivity and the responsivity were determined as ~ 6 × 105 cm Hz1/2 W−1 and 36 V W−1 respectively at a 10 Hz chopper frequency with 50 μA bias current for a thermal conductance G ~ 10−3 W K−1 between the thermal sensing layer and the substrate. The preliminary results for the test microbolometer array are discussed and compared with those for microbolometers fabricated on micromachined thermally isolated structures.

Synthesis and ion dynamics studies of nanocrystalline Mg stabilized zirconia

Abstract: The nanocrystalline Mg stabilized zirconia with 18 and 22 mol% were prepared by co-precipitation method. The formation of the mixed cubic and tetragonal phases have been observed from X-ray diffractogram studies. The impedance Cole–Cole plot shows the grain interior and grain boundary resistance contributions. The conductance spectra show the DC plateau and dispersive region suggesting the correlated hopping motion of ions. The charge carrier concentration is found to be increasing with Mg doping and hence high conductivity. The dielectric spectra shows step-like feature and suggests the presence of additional relaxation, which has the intrinsic character.

Mate Selection and Female Age at Marriage: A Micro Level Investigation in Tamil Nadu, India

Abstract: This paper aims to examine the process of mate selection in determining the age at marriage of 600 ever-married women drawn from rural (300) and urban (300) areas of Salem district, Tamil Nadu. Res...

Field and temperature-dependent electronic transport parameters of amorphous and polycrystalline GaSe thin films

Abstract: DC electrical conduction studies on vacuum evaporated thin films of GaSe in both the amorphous and polycrystalline states using the Al–GaSe–Al sandwich structure has been performed. Under low electric field (∼2.2×10 5 V cm −1 ) condition, in amorphous films in the temperature range 250–310 K and in polycrystalline films in the temperature range 190–250 K the variable-range hopping conduction of Mott's type is identified. For the same field, the Seto's model of thermionic emission for polycrystalline film (280–370 K) perfectly suits. The amorphous and polycrystalline GaSe thin films have localized states density values of N ( E F )=1.686×10 17 and 1.257×10 15 cm −3 eV −1 , respectively. The activation energies are found to be 0.317 and 0.087 eV, respectively for these two forms of material. The analysis of I–V characteristics, based on space charge limited currents measurements, confirms the exponential decrease of density of states from the conduction band edge towards the Fermi level for both the amorphous and polycrystalline films.