Showing papers by "Banaras Hindu University published in 1996"

Bacopa Monniera Linn. As an Antioxidant: Mechanism of Action

Abstract: Bacopa monniera, Linn. (Brahmi: Scrophulariaceae) an Ayurvedic medicine is clinically used for memory enhancing, epilepsy, insomnia and as mild sedative. For the first time the effect of alcohol and hexane fraction of Brahmi has been studied on FeSO4 and cumene hydroperoxide induced lipid peroxidation. Alcohol fraction showed greater protection with both inducers. Results were compared with known antioxidants tris, EDTA and a natural-antioxidant vitamin E. The effect of Brahmi was also examined on hepatic glutathione content. The mechanism of action could be through metal chelation at the initiation level and also as chain breaker. The results suggested that Brahmi is a potent antioxidant. The response of Brahmi was dose dependent. Tris, an hydroxyl trapper did not show any protection in comparison to Brahmi where as EDTA and vitamin E did protect against FeSO4. In experimental conditions 100 micrograms Brahmi extract (alcoholic) was equivalent to 247 micrograms of EDTA (0.66 microM) and 58 micrograms of vitamin E. Interestingly Brahmi only slightly protected the autooxidation and FeSO4 induced oxidation of reduced glutathione on lower doses 100 micrograms/ml and below, but on higher concentrations it enhanced the rate of oxidation.

Effects of UV irradiation on certain physiological and biochemical processes in cyanobacteria

Abstract: The effects of artificial UV (280–400 nm, 5 W m−2) radiation on heterocyst differentiation, nitrogenase activity, 14CO2 uptake and protein profile of whole cell and isolated heterocysts have been studied in four cyanobacterial strains isolated from Indian rice paddy fields. Exposure of cells to UV for 1 h significantly affected the differentiation of vegetative cells into heterocysts in four cyanobacterial strains studied (Anabaena sp., Nostoc sp., Nostoc carmium and Scytonema sp). Almost 50% fewer heterocysts were recorded in Anabaena sp. and Scytonema sp. and nearly 70% fewer in Nostoc sp. and Nostoc carmium after UV radiation in comparison with controls without UV. Nitrogenase activity in Anabaena sp. was completely inhibited within 45 min of UV exposure. 14CO2 uptake in Anabaena sp. was also severely affected by UV radiation. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS PAGE) analyses of the total protein profile of Anabaena sp. showed a linear decrease in the protein content with increasing UV exposure time. Almost complete elimination of most of the protein bands occurred after 120 min of UV exposure. The SDS PAGE protein profile of isolated heterocysts of Anabaena sp. showed three prominent polypeptides of 26, 54 and 55 kDa, with a decrease in the first two and complete elimination of the last one after 1 h of UV radiation.

Cross-cultural alexithymia : Development and validation of a Hindi translation of the 20-item Toronto Alexithymia Scale

Abstract: The possibility that alexithymia may be a culture-bound construct was evaluated by developing a Hindi version of the Twenty-Item Toronto Alexithymia Scale and assessing its psychometric properties in a sample of 285 normal young adults in India. The Hindi version of the scale (TAS-20-H) showed excellent cross-language equivalence with the English version. In addition, the TAS-20-H demonstrated adequate internal consistency, good test-retest reliability, and a three-factor structure consistent with the three-factor model of the original scale.

Photobiology and Ecophysiology of Rice Field Cyanobacteria

Abstract: Cyanobacteria (blue-green algae) are phylogenetically a primitive group of gram-negative prokaryotes being the only bacteria to possess higher plant-type oxygenic photosynthesis. They also have the capacity to metabolize CO,, O,, N2 and H2 (1). Fossil evidence dates their appearance to the Precambrian era. Stromatolithic mats composed of cyanobacteria are dated at over 2.8 (or possibly 3.5) X lo9 years and appear nearly identical to those found today (2,3). Cyanobacteria are the largest and most widely distributed group of photosynthetic prokaryotes on earth and as a group are thought to have survived from a wide spectrum of environmental stresses such as heat and cold shock, drought, salinity, nitrogen starvation, photooxidation, anaerobiosis, osmotic and UV stress, erc. (4-6). Cyanobacteria are unique in having a cosmopolitan distribution ranging from hot springs to arctic regions. Cyanobacterial colonization of oceans, lakes, rivers, hot springs and soils, and their presence as symbiotic organisms in fungi and plants demand high variability in adapting to diverse environmental factors. Cyanobacterial populations occupy an important place in both aquatic as well as terrestrial ecosystems and achieve net photosynthesis even at temperatures as low as -7°C (7) and as high as 75°C (8). Members of cyanobacteria also possess a central position in the nutrient cycling largely due to their inherent capacity to fix atmospheric N2 with the help of the enzyme nitrogenase, directly into ammonium (MI4+). a form through which nitrogen enters into the food chain (9). Estimates vary as to the contribution of biological nitrogen fixation (BNF)? to the global nitrogen cycle, but according to one assumption cyanobacteria fix over 35 million tons of nitrogen annually, which is thus available for use by higher plants (10). In several instances the availability of

Meconium stained amniotic fluid: antenatal, intrapartum and neonatal attributes.

Abstract: Objectives : To find out the incidence, outcome as well as antenatal, intrapartum and neonatal attributes of meconium stained amniotic fluid (MSAF). Design : Prospective study. Setting : Neonatal Unit of Hospital. Subjects : 1426 live births occurring in 1500 consecutive deliveries, over one year period. Interventions : In all babies born through MSAF, thorough oropharyngeal suction as soon as the head was delivered followed by immediate intratracheal intubation and suctioning in infants depressed at birth. Results : 204 (14.3%) deliveries had MSAF of which thick meconium was present in 141. Hepatitis in mother, fetal distress during labor and intrauterine growth retardation were significant factors associated with MSAF. One fifth of babies born through MSAF suffered severe birth anoxia compared to 5.6% in non-MSAF group. The consistency of meconium had direct bearing on the neonatal outcome. Severe birth asphyxia (SBA) occurred in 27.0 and 6.3% of babies with thick and thin meconium staining, respectively. Meconium aspiration syndrome was observed in 9 babies of thick meconium group and 8 of these were depressed at birth. All deaths occurred in thick meconium group and were associated with SBA. Conclusions : Selective approach can be adopted for babies with MSAF reserving intratracheal suctioning at birth for depressed neonate or evidence of fetal distress in utero. Rest of the neonates only need careful observation after thorough oronasopharyngeal suctioning.

Fetal iron status in maternal anemia

Abstract: Hemoglobin, serum iron, transferrin saturation and ferritin were measured on paired maternal and cord blood samples in 54 anemic (hemoglobin < 110 g/L) and 22 non-anemic (hemoglobin ≥ 110 g/L) pregnant women at term gestation. The levels of hemoglobin, serum iron, transferrin saturation and ferritin were significantly low in the cord blood of anemic women, suggesting that iron supply to the fetus was reduced in maternal anemia. The linear relationships of these parameters with both maternal hemoglobin and maternal serum ferritin indicated that the fetus extracted iron in amounts proportional to the levels available in the mother. Infants of mothers with moderate and severe anemia had significantly lower cord serum ferritin levels and hence poor iron stores at birth. It is concluded that iron deficiency anemia during pregnancy adversely affects the iron endowment of the infant at birth.

A model for primary and heterogeneous secondary reactions of wood pyrolysis

Abstract: A chain growth model for heterogeneous secondary reactions is developed for the pyrolysis of large wood particles and the parameters determined by nonlinear optimization. The model takes both the volatile retention time and cracking and repolymerization reactions of the vapours with the decomposing solid as well as sutocatalysis into consideration. The extent of the secondary reactions is strongly influenced by the time and the ratio of the autocatalytic (propagation) reaction rate to noncatalytic (initiation) reaction rate. The wood which has a higher value of the autocatalytic/noncatalytic ratio also has a higher exothermic heat of reaction and yields a higher amount of final char residue. This fact confirms the heterogeneous secondary reactions lead to carbon enrichment of the final residue and are accompanied with an exothermic heat of reaction. The lower activation energies of the initiation and propagation reactions as compared to primary reactions (competitive reaction model consisting of weight loss and char forming reactions) confirm autocatalysis in large particles. The sealed reactor studies of small quantities of fine wood samples show that heterogeneous secondary reactions and not lower heating rates in large particles are the main source of char formed during the thermal decomposition of large wood particles. The model predictions are in agreement with the weight loss and temperature versus time curves over a wide range of particle size and furnace temperatures.

Effect of composition on dielectric and electrical properties of the Sr1 −x La x Ti1 −x Co x O3 system

Abstract: Valence compensated perovskite system Sr1 −x La x Ti1 −x Co x O3 shows dielectric relaxor behaviour with very high value of dielectric constant in the composition range 0·20

Methane flux from rice/wheat agroecosystem as affected by crop phenology, fertilization and water level

Abstract: Methane flux was measured for a rice/wheat agroecosystem of Gangetic Plains, with and without application of chemical fertilizer and wheat straw (WS). Three treatments of control, fertilizer application and fertilizer + WS application, were established in a completely randomized block design and measurements were made for two consecutive years (1993 and 1994). CH4 measurements during growth of the rice crop period showed that there were significant difference in flux rates during the two years. Maximum emission occurred at the time of anthesis and minimum at the seedling stage. The flux rates were significantly higher for fertilizer or fertilizer + WS treatments. The effects of the treatments were similar across phenological stages and years. In the subsequent wheat crop and fallow period, the soils consumed CH4. There were significant differences in CH4 uptake rates between the two years. Fertilizer treatments reduced CH4 uptake in both the years. The results suggested that tropical agroecosystems may consume substantial amounts of CH4 and that the methane output can be reduced by lowering the submergence level in rice paddies.

Water-stable aggregates and associated organic matter in forest, savanna, and cropland soils of a seasonally dry tropical region, India.

Abstract: The study was undertaken to quantify the distribution of soil in different size fractions of water-stable aggregates, and organic C, total N, and total P associated with these aggregates, along a gradient of forest-savanna-cropland in the Indian dry tropics. The effect of residue (wheat straw) amendment under dryland cultivation was also investigated. Proportions of macroaggregates (>0.3 mm) were highest in the forest and lowest in the cropland soil and ranged from 58–66% in forest, to 55% in savanna and 25–36% in cropland. In contrast, microaggregates ( 0.05) in the short term, although the proportion of macroaggregates increased, indicating an improvement in soil structure. Thus soil degradation after conversion of natural systems to cropland can be arrested up to some extent by residue input to the soil.

A Model of the universe with decaying vacuum energy

Abstract: The consequences of taking the total active gravitational mass of the universe phasewise constant together with a decaying vacuum energy in the background of Robertson-Walker space-time are investigated. The model so determined admits a contracted Ricci-collineation along the fluid flow vectorν i. It is geometrically closed but ever-expanding and does not possess the initial singularity, horizon, entropy, monopole or cosmological constant problems of the standard big bang cosmology. Estimates of the present matter; radiation and vacuum energy densities, the age of the universe and the present values of the deceleration parameter and the scale factor are also obtained.

Antistress Activity of Tinospora cordifolia and Centella asiatica Extracts

Abstract: Tinospora cordifolia Miers. and Centella asiatica Linn. were screened for their putative antistress activity in a battery of experiments. Ethanol extracts of both drugs at 100 mg/kg exhibited significant antistress activity in all the parameters studied, compared with diazepam at 2.5 mg/kg.

E.s.r. studies on acylhydrazine and hydrazone copper(II) sulfate complexes

Abstract: CuII complexes of the [CuL2(SO4)]·nH2O and [CuL′(SO4)(H2O)2]·nH2O type, where L = benzoylhydrazine (PhCONHNH2; BH) or iso-propanone benzoylhydrazone (PhCONHN:CMe2; IBH), L′= iso-nicotinoylhydrazine (NC5H4CONHNH2; INH) or isopropanone iso-nicotinoylhydrazone (NC5H4CONHN: CMe2; IINH); n = 0–2, were prepared and characterized by elemental analyses, molar conductances, and electronic, e.s.r. and i.r. spectral measurements. The electronic and e.s.r. spectra suggest a tetragonally distorted octahedral geometry in the solid state as well as in DMSO solution. The e.s.r. data also reveal an axial symmetry for most of the complexes in the solid state and in DMSO solution at 300 and 77 K, while the complex of IBH is isotropic at 300 K. The ΔMs = 2 transition observed for this complex suggests that it is a dimer. BH and INH bond to CuII through the C-O and NH2 groups, whereas IBH and IINH bond through C-O and C-N groups.

Transient free convection flow between two vertical parallel plates

Abstract: Transient free convection flow between two infinite vertical parallel plates has been investigated and good agreement was found between the results for large values of time and the well known ones for the steady-state problem.

Effects of Ni, Fe, Cu, and Cr Substitutions for Co in La0.8Sr0.2CoO3 on Electrocatalytic Properties for Oxygen Evolution

Abstract: The influence of some transition metal ion substitutions in the active 0.2 mole strontium-doped lanthanum cobaltate (La{sub 0.8}Sr{sub 0.2}Co{sub 1-y}B{sub y}O{sub 3} with B = Ni, Fe, Cu, and Cr; 0.1 {<=} y {<=} 0.4) lattice was studied on the electrocatalytic properties of the oxide by cyclic voltammetry and Tafel polarization techniques. The cyclic voltammetry showed a pair of redox peaks prior to the onset of oxygen evolution, regardless of the nature of the substitution. The presence of Fe or Ni, in small quantities enhanced the electrochemically active area. The anodic polarization studies indicated two Tafel slopes: {approximately}2.3 RT/F at low and {approximately}2(2.3 RT/F) at high overpotentials. The oxygen evolution reaction on each B-site substituted perovskite followed first-order kinetics with respect to OH{sup {minus}} ion concentration. The La{sub 0.8}Sr{sub 0.2}Co{sub 0.9}Fe{sub 0.1}O{sub 3} and La{sub 0.8}Sr{sub 0.2}Co{sub 0.9}Ni{sub 0.1}O{sub 3} electrodes showed the highest electrocatalytic activity based on geometrical surface area. Copper and chromium substitutions had detrimental effects on the electrocatalytic activity.

A review on economical treatment of wastewaters and effluents by adsorption

Abstract: The review gives an overview of the application of non‐conventional materials for treatment of wastewater and industrial effluents. Based on the findings, it is concluded that the easily available and economical materials can serve as alternates to the more costly activated carbon/activated charcoal.

High androgen production by ovarian thecal interstitial cells: a mechanism for delayed ovulation in a tropical vespertilionid bat, Scotophilus heathi.

Abstract: The steroid hormone profile of Scotophilus heathi, an Indian tropical vespertilionid bat, was studied, with special reference to the period of delayed ovulation. The results show unusually high concentrations of circulating androstenedione and testosterone during the first half of the period of delayed ovulation, whereas the concentrations of progesterone and oestradiol were relatively low during this period. Androstenedione, testosterone and oestradiol concentrations were high during the period of ovarian recrudescence (October-November). The oestradiol concentration increased, whereas androstenedione and testosterone declined significantly, before ovulation. Studies in vitro showed that the ovary secretes more androstenedione and testosterone than does the adrenal. A histological study showed that a major part of the ovary of S. heathi was occupied by hypertrophied interstitial cells. An immunocytochemical study showed ovarian thecal interstitial cells as the major site of high androgen synthesis in the ovary. During the period of delayed ovulation the bat ovaries thus resemble the ovaries from women with polycystic ovaries in which abnormally high androgen secretion from hypertrophied interstitial cells prevent ovulation.

Population and behaviour genetics of Drosophila ananassae.

Abstract: Drosophila ananassae is a cosmopolitan and domestic species. It occupies a nuique status among the Drosophila species due to certain peculiarities in its genetic behaviour. The most unusual feature of this species is spontaneous male recombination in appreciable frequency. The present review summarises the work done on population and behaviour genetics of D. ananassae from India. Population dynamics of three cosmopolitan inversions has been studied in Indian population of D. ananassae and it is evident from the results that there is a considerable degree of genetic divergence at the level of inversion polymorphism. In general, the populations from south India show more differentiation than those from the north. These three cosmopolitan inversions, which are coextensive with the species, exhibit heterosis. Interracial hybridization does not lead to beaakdown of heterosis, which suggests that evidence for coadaptation is lacking in geographic populations of D. ananassae. Heterosis appears to be simple luxuriance rather than populational heterosis (coadaptation). Unlinked inversions occur in random associations, indicating no interchromosomal interactions. However, two inversions of the third chromosome often show strong linkage disequilibrium in laboratory populations, which is due to epistatic gene interaction and suppression of crossing-over. Genetic variations for certain allozyme polymorphism and sternoleural bristle phenotypes in Indian populations of D. ananassae have also been observed.