Showing papers by "Banaras Hindu University published in 1995"
TL;DR: In this paper, a poly(ethylene oxide)-NaPF6 polymer electrolytes have been studied by X-ray diffraction, IR, differential thermal analysis, optical microscopy, polarization, and impedance spectroscopic techniques.
Abstract: Poly(ethylene oxide)-NaPF6 polymer electrolytes have been studied by X-ray diffraction, IR, differential thermal analysis, optical microscopy, polarization, and impedance spectroscopic techniques. The material is shown to be an ionic conductor with tion ≈ 0.98, tNa+ ≈ 0.45 and tanion ≈ 0.53. The σ vs. 1 T curves show apparent Arrhenius behaviour below and above Tm.
144 citations
Journal Article•
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TL;DR: Congestion is an inherent problem for networks with multiple user access when the load exceeds what can be handled even with optimal routing, so window flow control and rate flow control schemes are discussed.
Abstract: Information technology's growth has led to an obsession to provide better and more communication services than ever before. Computer communication networks are the latest manifestation of this obsession. Computer networks have been playing an increasingly larger role in our day to day activities. However, there is technology available that makes it possible for us to envision simultaneous transmission of voice, video, graphics and text over the same network. Such networks are called broadband integrated services digital networks (B-ISDNs). For a B-ISDN to be successful, certain critical issues such as congestion control, routing and error detection have to be tackled. Congestion is an inherent problem for networks with multiple user access when the load exceeds what can be handled even with optimal routing. Window flow control and rate flow control schemes are discussed.
121 citations
TL;DR: In this paper, a vertical section Ti-27.5Al up to 25 at% Nb in the ternary Ti-3Al-Nb system is described.
108 citations
TL;DR: The findings validate the medharasayan (promoter of learning and memory) effect of W. somnifera, as has been reported in Ayurveda, and reverse both IA‐induced cognitive deficit and the reduction in cholinergic markers after 2 weeks of treatment.
Abstract: The active principles of Withania somnifera (WS, 20–50 mg/kg, p.o.), consisting of equimolar amounts of sitoindosides. VII–X and withaferin A, were investigated for putative nootropic activity in an experimentally validated Alzheimer's disease (AD) model. The syndrome was induced by ibotenic acid (IA) lesioning of the nucleus basalis magnocellularis (NBM) in rats. Cognitive deficits induced in NMB-lesioned rats were assessed by attenuation of a learned active avoidance task and a decrease in frontal cortical and hippocampal acetylcholine (ACh) concentrations, choline acetyltransferase (ChAT) activity and muscarinic cholinergic receptor (MCR) binding. IA-induced NBM lesioning in rats caused a marked cognitive deficit, as evidenced by severe reduction of the learned task, and was accompanied by a significant decrease in frontal cortex and hippocampal ACh levels, ChAT activity and MCR binding. WS (50 mg/kg) significantly reversed both IA-induced cognitive deficit and the reduction in cholinergic markers after 2 weeks of treatment. The findings validate the medharasayan (promoter of learning and memory) effect of W. somnifera, as has been reported in Ayurveda.
107 citations
TL;DR: In this article, changes in the soil microbial biomass following applications of farmyard manure and inorganic fertilizer, alone and in combination, were studied for two annual cycles in a rice-lentil crop sequence grown under rainfed tropical dryland conditions.
Abstract: Changes in the soil microbial biomass following applications of farmyard manure and inorganic fertilizer, alone and in combination, were studied for two annual cycles in a rice-lentil crop sequence grown under rainfed tropical dryland conditions. During the two annual cycles the microbial biomass C range (μg g-1) was 146–241 (x = 204), 191–301 (245), 244–382 (305), and 294–440 (365) in control, fertilizer, manure and manure+fertilizer plots, respectively. The corresponding ranges for microbial biomass N (μg g-1) were 16.5–21.0 (19.5), 20.4–38.2 (26.0), 23.0–34.6 (27.0) and 26.2–42.4 (33.3), and for microbial biomass P (μg g-1) 4.4–8.2 (7.0) 6.0–11.2 (9.6), 11.2–22.0 (17.0), and 10.0–25.4 (18.3). The maximum increase in the microbial biomass, due to these inputs was observed under the manure+fertilizer treatment followed, in decreasing order, by manure alone and fertilizer alone. Within individual crop periods the levels of microbial biomass decreased sharply from the seedling to the flowering stage and then increased slightly with crop maturity. The maximum levels of microbial biomass C and P were observed during the summer fallow. The maximum accumulation of microbial biomass N occurred in the early rainy season, immediately after the soil amendments. Microbial biomass C, N, and P were positively related to each other throughout the annual cycle.
101 citations
TL;DR: In this article, the seasonal dynamics of mineral N (NH4+ and NO3−), available P (NaHCO3Pi) and N-mineralization rates in patchy and adjacent microsites of a dry tropical forest were examined in relation to fine root biomass.
Abstract: Seasonal dynamics of mineral N (NH4+ and NO3−), available P (NaHCO3Pi) and N-mineralization rates in patchy and adjacent microsites of a dry tropical forest were examined in relation to fine root biomass. Patchy microsites were richer in mineral N and P. Year-long averages indicated that NH4+ dominated over NO3− in the nutrient rich patchy microsites where fine root biomass, production and turnover were comparatively greater than in the nutrient-poor adjacent microsites which were dominated by NO3−. However, during the wet season nitrate was the dominating form of mineral-N in all the microsites. N-mineralization was higher in the patchy microsites than in the adjacent microsites. Fine root biomass was positively correlated with the N-mineralization and nitrification rates in nutrient-rich microsites indicating that fine root development was facilitated by higher amounts of mineral-N irrespective of the form in which N was prevalent.
101 citations
TL;DR: In this paper, the experimental results pertinent to the penetration of steel plates of varying hardness in the range HV295-HV520 and of thickness 20 and 80 mm by ogive-shaped 20mm-diameter projectiles over the velocity range 300-800 m s −1.
97 citations
TL;DR: The effect of Sr2+ substitution on the structure and dielectric behaviour of BaTiO3 is reported in this article, where it is shown that the smearing of the variation of the Dielectric constant with temperature in such samples is not due to compositional inhomogeneities.
Abstract: The effect of Sr2+ substitution on the structure and dielectric behaviour of BaTiO3 is reported It is shown that the smearing of the variation of dielectric constant with temperature in such samples is not due to compositional inhomogeneities Observation of relaxational dipolar freezing below the hump temperature indicates the similarity of diffuse ferroelectric transition and orientational glass behaviour
89 citations
TL;DR: In this article, the distribution of microbial biomass associated with water-stable macro-and microaggregates in soils was studied along a forest-savanna-cropland gradient.
Abstract: The distribution of microbial biomass associated with water-stable macro- and microaggregates in soils was studied along a forest-savanna-cropland gradient. In both macro- and microaggregates, mean microbial biomass C, N and P were maximum in forest and minimum in cropland soils. At all the sites microbial C was greater in the macroaggregate than the microaggregate size class, whereas microbial biomass N and P were greater in the microaggregates. The microbial C-to-nutrient ratios were lower for the microaggregates compared to macroaggregates. It is possible that these two size classes support two different types or components (fungi-dominated and bacteria-dominated) of the food web in soil. There was a decrease in the amount of microbial C, N and P in both macro- and microaggregates along the forest-savanna-cropland gradient, which was due to the reduction of total soil organic matter. Total soil organic C and total N showed significant positive relations with both macro- and microaggregate microbial C and N, indicating that the latter are limited by the quantity of soil organic matter.
89 citations
TL;DR: In this paper, the dispersion-strengthened copper composites containing 0.3 wt% Al 2 O 3 were sintered in hydrogen at temperatures of 800°C and 900°C.
86 citations
TL;DR: In this article, the synthesis of the hydrogen storage alloy Mg2Ni has been carried out through a single-step mechanical alloying employing an energy ball mill, which has been found to exist in the form of fine (nano) particles with sizes of about 40 A. The nanoparticles lead to easy activation for hydrogenation by annealing at 300 °C (about 10−4 Torr vacuum).
01 Apr 1995
TL;DR: SDS PAGE analysis of the fractions revealed a loss of high molecular mass linker proteins and low molecular mass (αβ monomers indicating that the phycobiliproteins, which function as accessory pigments for the operation of photosystem II, disassemble during UV irradiation.
Abstract: The effects of UV (280–400 nm) irradiation on phycobiliprotein composition have been studied in two N2-fixing cyanobacteria, Anabaena sp. and Nostoc carmium, isolated from rice paddy fields in India. Phycobiliproteins were isolated and separated by sucrose density gradient centrifugation. After UV exposure the top fraction mainly contained carotenoids (absorption maximum at 485 nm), which first showed an increase in intensity and absorption and then a gradual decrease with increasing UV exposure in Anabaena sp., whereas, in Nostoc carmium this fraction showed a steady increase over the whole exposure time. The bottom fraction of both organisms mainly contained phycocyanin (absorption peak at 620 nm) which showed a steady decline in intensity, as well as absorption. Fluorescence excitation at 620 nm resulted in an emission at 650 nm which underwent a shift towards shorter wave-lengths with increasing UV-exposure time, indicating a disassembly of the phycobilisomal complex and of impaired energy transfer from accessory pigments to the reaction centers. SDS PAGE analysis of the fractions revealed a loss of high molecular mass linker proteins and low molecular mass (αβ monomers indicating that the phycobiliproteins, which function as accessory pigments for the operation of photosystem II, disassemble during UV irradiation.
TL;DR: Results indicate that both environmental photoperiod and temperature and E2-negative feedback act on the CA to modulate GTH secretion.
TL;DR: In this paper, the isothermal decomposition of the α2-to-O(O1)-phase in a Ti-28.5 at.% A1-13 at.%.
Abstract: The α2-to-O transformation, with its characteristic microstructural features, occurs across the entire range of compositions in alloys based on the Ti3A1-Ti2AINb system. In this paper, we describe the isothermal decomposition of the α2-to the O(O1)-phase in a Ti-28.5 at.% A1–13 at.% Nb alloy, in the first detailed study of this transformation. Both parent and product phases are ordered with an identical site occupancy. The transformation is accomplished by a lattice distortion and a small composition change. The microstructural features and patterns that evolve during the diffusional growth and coarsening of the O-phase are shown to be dominated by the strain energy associated with the transformation. The orientation relationships, habit plane and the self-accommodating nature of the product variants are therefore explained by simple analyses in terms of the phenomenological theory of martensitic transformations.
TL;DR: A hexane extract of the stem bark of Polyalthia longifolia furnished nine new clerodane and ent-halimane diterpenes, i.e. 16-hydroxycleroda-4(18), 13-dien-16,15-olide, 16-oxocleroda- 4(18,13 E -dien15-oic acid, ent -halima-1(10),13 E −dien -16, 15-oline, ent −halima -5(10), ent −hima-
TL;DR: The nmr results suggest that Acnc peptides adopt folded β‐turn conformations with Ala(1) and Acnc(2) occupying i + 1 and i + 2 positions, while the Dxg peptides favor extended C5 conformations, which are clearly borne out in CD studies.
Abstract: The conformational properties of alpha,alpha-dialkylated amino acid residues possessing acyclic (diethylglycine, Deg; di-n-propylglycine, Dpg; di-n-butylglycine, Dbg) and cyclic (1-aminocycloalkane-1-carboxylic acid, Acnc) side chains have been compared in solution. The five peptides studied by nmr and CD spectroscopy are Boc-Ala-Xxx-Ala-OMe, where Xxx = Deg (I), Dpg (II), Dbg (III), Ac6c (IV), and Ac7c (V). Delineation of solvent-shielded NH groups have been achieved by solvent and temperature dependence of NH chemical shifts in CDCl3 and (CD3)2SO and by paramagnetic radical induced line broadening in peptide III. In the Dxg peptides the order of solvent exposure of NH groups is Ala(1) > Ala(3) > Dxg(2), whereas in the Acnc peptides the order of solvent exposure of NH groups is Ala(1) > Acnc(2) > Ala(3). The nmr results suggest that Acnc peptides adopt folded beta-turn conformations with Ala(1) and Acnc(2) occupying i + 1 and i + 2 positions. In contrast, the Dxg peptides favor extended C5 conformations. The conformational differences in the two series are clearly borne out in CD studies. The solution conformations of peptides I-III are distinctly different from the beta-turn structure observed in crystals. Low temperature nmr spectra recorded immediately after dissolution of crystals of peptide II provide evidence for a structural transition. Introduction of an additional hydrogen-bonding function in Boc-Ala-Dpg-Ala-NHMe (VI) results in a stabilization of a consecutive beta-turn or incipient 3(10)-helix in solution.
TL;DR: In this paper, the structure and properties of a solution treated, cold worked and aged Cu-4.5%Ti alloy were studied by means of optical, scanning and transmission electron microscopy as well as hardness, tensile tests and electrical conductivity measurements.
Abstract: The structure and properties of a solution treated, cold worked and aged Cu-4.5%Ti alloy were studied by means of optical, scanning and transmission electron microscopy as well as hardness, tensile tests and electrical conductivity measurements. Prior cold work (rolling) increases the peak hardness from 340 to 425 VHN, the tensile strength from 890 to 1380 MPa and the conductivity from 10 to 25% IACS on aging the alloy in the temperature range from 400 to 450°C. Maximum strengthening of the alloy is attributed to the precipitation of a coherent, metastable β' phase (Cu 4 Ti). The alloy is deformed through profuse twinning. The ductile mode of fracture of the aged alloy is not affected by the prior cold work.
TL;DR: In this article, the system studied is PEO∶NH4I, dispersed with α-Al2O3, which has been characterized using various techniques such as X-ray diffraction (XRD), differential thermal analysis (DTA), polarization and complex impedance spectroscopy.
Abstract: Ion conducting polymer electrolyte films having high salt concentrations have been studied. The system studied is PEO∶NH4I, dispersed with α-Al2O3. Mechanically stable films with NH 4 + /EO ratio ≥0.13 have been obtained by dispersal of Al2O3. The films have been characterized using various techniques such as X-ray diffraction (XRD), differential thermal analysis (DTA), polarization and complex impedance spectroscopy. Intercorrelation between polymer matrix crystallite size, conductivity, and α-Al2O3 particle size is established.
TL;DR: In this article, thin films of NiCo2O4 were prepared on Ni at 370 °C by the method of spray pyrolysis, and the films were uniform, adherent, free from cracks and electrocatalytically much more active for oxygen evolution than other NiCo 2O4 films recently reported in the literature.
TL;DR: The ethanol extracts of the roots of T. cordifolia Miers and C. asiatica Linn were observed to induce a marked protective action against an 8 h restraint stress induced ulcerization, the activity being comparable to that of diazepam.
Abstract: The ethanol extracts of the roots of T. cordifolia Miers and C. asiatica Linn were observed to induce a marked protective action against an 8 h restraint stress induced ulcerization, the activity being comparable to that of diazepam.
TL;DR: In this article, the authors present information on the inhibition of carbon fixation, O2-evolution, photosynthetic electron transport chain, ATP pool and respiration rate of the cyanobacterium A. doliolum by UV-B and Cu.
TL;DR: A remarkable feature of this ABA effect was that the bulk of the buds regenerated away from the cut ends directly from the epidermis without any apparent callus formation, which may be useful for germplasm conservation.
TL;DR: The radicophilicity (antiradical–antioxidant effects) of processed shilajit to oxygen‐derived free radicals and nitric oxide, and the attendant H2O2 cleaving effect were evaluated and are consistent with the therapeutic uses of shiljit as an Ayurvedic rasayan (rejuvenator) against oxidative stress and geriatric complaints.
Abstract: The radicophilicity (antiradical-antioxidant effects) of processed shilajit (SJP) to oxygen-derived free radicals and nitric oxide (NO), and the attendant H 2 O 2 cleaving effect were evaluated. SJP provided complete protection to methyl methacrylate (MMA) against hydroxyl radical-induced polymerization and acted as a reversible NO-captodative agent. SJP (20 and 50 mg/kg/day, i.p., for 21 days) induced a dose-related increase in superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) activities in frontal cortex and striatum of rats. The data were comparable to those of (-)-deprenyl (2 mg/kg/day, i.p., for 21 days) in respect of SOD and CAT activities. These findings are consistent with the therapeutic uses of shilajit as an Ayurvedic rasayan (rejuvenator) against oxidative stress and geriatric complaints
TL;DR: The investigation supports the postulated role of tribulin as an endogenous correlate of anxiety, its MAO A inhibitory component accounting for a major part of this effect.
TL;DR: In this article, the Einstein field equations of massive strings are solved completely with and without a source free magnetic field for the Bianchi type I metric in a different basic form, and physical properties of the models are studied.
Abstract: The Einstein field equations of massive strings are solved completely with and without a source free magnetic field for the Bianchi type I metric in a different basic form Some physical properties of the models are studied
TL;DR: It appears that DNA methylation plays a critical role in the differentiation of gonia into primary spermatocytes as well as proliferation and differentiation of germ cells in testis.
Abstract: In order to explore the significance of DNA methylation in proliferation and differentiation of germ cells in testis, 5-aza,2′-deoxycytidine (5-azaCdR), a hypomethylating agent, was administered in vivo to neonatal mice having only spermatogonial (premeiotic) cells. End-labeling of the Mspl, Hpall, and Hhal digested DNA revealed considerable loss of methylation following the treatment. Cellular and histological preparations of the testis showed complete inhibition of differentiation into spermatocytic stage. Analysis of protein synthesis in the treated and control testis by growing the cells in 35S-Methionine medium and resolving the lysate by SDS-PAGE revealed that the programme of expression of at least 5 polypeptides (35.0, 31.5, 27.0, 22.5, and 18.0 KD) was altered as a result of 5-azaCdR incorporation. It appears that DNA methylation plays a critical role in the differentiation of gonia into primary spermatocytes. © 1995 wiley-Liss, Inc.
TL;DR: In this article, a class of pseudo-differential operators (p.d.o.), generalizing Bessel differential operator d2/dx2 + (1 − 4μ2)/(4x2), is defined.
TL;DR: In this article, the results of Mossbauer spectroscopic investigations of the transformations of different iron-bearing minerals in some Indian coals of different geological origin with varying mineral contents during their ashing and pulverished fuel combustion (PFC).
TL;DR: Inoculated seedlings significantly reduced the disease incidence and severity of Rhizoctonia damping-off of tomato seedlings and loss of endogenous C compounds from sclerotia was correlated with repression of germination.
Abstract: Rhizobacteria isolated from the rhizosphere of tomato plants were used to inoculate seeds and roots in greenhouse assays. Three bacteria, Azospirillum sp., Azotobacter chroococcum and Pseudomonas fluorescens, provided a significant (P = 0.05) increase in seedling emergence rate. A. chroococcum was found most effective in increasing the total dry weight, root and shoot length of tomato plants, followed by P. fluorescens and Azospirillum sp. Variations in incubation temperature and soil moisture significantly (P = 0.01) influenced the total plant growth. Temperatures >30°C were not favourable for bacterial activity or plant growth. Inoculated seedlings at −5 kPa (25°C) showed maximum plant growth, whereas least response was observed at −15 kPa. Inoculated seedlings significantly (P = 0.05) reduced the disease incidence and severity of Rhizoctonia damping-off of tomato seedlings. Colonization of Rhizoctonia solani sclerotia by rhizobacteria was negatively correlated with germination of sclerotia in patato dextrose broth (r = −0.84) and in Pfeffer's salts solution (r = 0.85). Bacteria were able to release 14C-labelled endogenous compounds from labelled sclerotia. Sclerotia exuded 37% (percentage of total label) 14C-labelled carbonaceous compounds in soil inoculated with P. fluorescens, 29% with A. chroococcum and 19% with Azospirillum sp. Loss of endogenous C compounds from sclerotia was correlated (r = −0.97) with repression of germination.