Showing papers by "Banaras Hindu University published in 2011"

Ultrathin Planar Graphene Supercapacitors

Abstract: With the advent of atomically thin and flat layers of conducting materials such as graphene, new designs for thin film energy storage devices with good performance have become possible. Here, we report an “in-plane” fabrication approach for ultrathin supercapacitors based on electrodes comprised of pristine graphene and multilayer reduced graphene oxide. The in-plane design is straightforward to implement and exploits efficiently the surface of each graphene layer for energy storage. The open architecture and the effect of graphene edges enable even the thinnest of devices, made from as grown 1−2 graphene layers, to reach specific capacities up to 80 μFcm−2, while much higher (394 μFcm−2) specific capacities are observed multilayer reduced graphene oxide electrodes. The performances of devices with pristine as well as thicker graphene-based structures are examined using a combination of experiments and model calculations. The demonstrated all solid-state supercapacitors provide a prototype for a broad ran...

Carbon footprint: current methods of estimation

Abstract: Increasing greenhouse gaseous concentration in the atmosphere is perturbing the environment to cause grievous global warming and associated consequences. Following the rule that only measurable is manageable, mensuration of greenhouse gas intensiveness of different products, bodies, and processes is going on worldwide, expressed as their carbon footprints. The methodologies for carbon footprint calculations are still evolving and it is emerging as an important tool for greenhouse gas management. The concept of carbon footprinting has permeated and is being commercialized in all the areas of life and economy, but there is little coherence in definitions and calculations of carbon footprints among the studies. There are disagreements in the selection of gases, and the order of emissions to be covered in footprint calculations. Standards of greenhouse gas accounting are the common resources used in footprint calculations, although there is no mandatory provision of footprint verification. Carbon footprinting is intended to be a tool to guide the relevant emission cuts and verifications, its standardization at international level are therefore necessary. Present review describes the prevailing carbon footprinting methods and raises the related issues.

Cyanobacteria: an emerging source for drug discovery

Abstract: The c group of Gram-negative gliding bacteria, has a long history of cosmopolitan occurrence. It has great biodiversity despite the absence of sexual reproduction. This wide biodiversity may be reflected in the wide spectrum of its secondary metabolites. These cyanobacterial secondary metabolites are biosynthesized by a variety of routes, notably by non-ribosomal peptide synthetase or polyketide synthetase systems, and show a wide range of biological activities including anticancer, antibacterial, antiviral and protease inhibition activities. This high degree of chemical diversity in cyanobacterial secondary metabolites may thus constitute a prolific source of new entities leading to the development of new pharmaceuticals.

Quasi-Molecular Fluorescence from Graphene Oxide

Abstract: Aqueous dispersions of graphene oxide (GO) have been found to emit a structured, strongly pH-dependent visible fluorescence. Based on experimental results and model computations, this is proposed to arise from quasi-molecular fluorophores, similar to polycyclic aromatic compounds, formed by the electronic coupling of carboxylic acid groups with nearby carbon atoms of graphene. Sharp and structured emission and excitation features resembling the spectra of molecular fluorophores are present near 500 nm in basic conditions. The GO emission reversibly broadens and red-shifts to ca. 680 nm in acidic conditions, while the excitation spectra remain very similar in shape and position, consistent with excited state protonation of the emitting species in acidic media. The sharp and structured emission and excitation features suggest that the effective fluorophore size in the GO samples is remarkably well defined.

Heavy-quark production in p + p and energy loss and flow of heavy quarks in Au + Au collisions at √sNN=200 GeV

Abstract: Transverse momentum spectra of electrons (p(T)(e)) from semileptonic weak decays of heavy-flavor mesons in the range of 0.3 < p(T)(e) < 9.0 GeV/c have been measured at midrapidity (|y| < 0.35) by the PHENIX experiment at the Relativistic Heavy Ion Collider in p + p and Au + Au collisions at root s(NN) = 200 GeV. In addition, the azimuthal anisotropy parameter v(2) has been measured for 0.3 < p(T)(e) < 5.0 GeV/c in Au + Au collisions. The substantial modification in the p(T)(e) spectra in Au + Au compared with p + p collisions as well as the nonzero v(2) indicate substantial interactions and flow of heavy quarks in traversing the produced medium. Comparisons of these observables with detailed theoretical calculations can be used to identify the nature of these interactions and to quantify their extent.

Measurement of neutral mesons in p+p collisions at √s=200GeV and scaling properties of hadron production

Abstract: The PHENIX experiment at the Relativistic Heavy Ion Collider has measured the invariant differential cross section for production of K-S(0), omega, eta', and phi mesons in p + p collisions at root s 200 GeV. Measurements of omega and phi production in different decay channels give consistent results. New results for the omega are in agreement with previously published data and extend the measured p(T) coverage. The spectral shapes of all hadron transverse momentum distributions measured by PHENIX are well described by a Tsallis distribution functional form with only two parameters, n and T, determining the high-p(T) and characterizing the low-p(T) regions of the spectra, respectively. The values of these parameters are very similar for all analyzed meson spectra, but with a lower parameter T extracted for protons. The integrated invariant cross sections calculated from the fitted distributions are found to be consistent with existing measurements and with statistical model predictions.

Measurements of higher order flow harmonics in Au+Au collisions at √sNN=200GeV

Abstract: Flow coefficients nu(n) for n = 2, 3, 4, characterizing the anisotropic collective flow in Au + Au collisions at root s(NN) = 200 GeV, are measured relative to event planes Psi(n), determined at large rapidity We report nu(n) as a function of transverse momentum and collision centrality, and study the correlations among the event planes of different order n The nu(n) are well described by hydrodynamic models which employ a Glauber Monte Carlo initial state geometry with fluctuations, providing additional constraining power on the interplay between initial conditions and the effects of viscosity as the system evolves This new constraint can serve to improve the precision of the extracted shear viscosity to entropy density ratio eta/s

An overview for exploring the possibilities of energy generation from municipal solid waste (MSW) in Indian scenario

Abstract: The energy crisis and environmental degradation are currently two vital issues for global sustainable development. Rapid industrialization and population explosion in India has led to the migration of people from villages to cities, which generate thousands tons of municipal solid waste daily, which is one of the important contributors for environmental degradation at national level. Improper management of municipal solid waste (MSW) causes hazards to inhabitants. The management of MSW requires proper infrastructure, maintenance and upgrade for all activities. The MSWM (municipal solid waste management) system comprises with generation, storage, collection, transfer and transport, processing and disposal of solid wastes. In the present study, an attempt has been made to provide a comprehensive review of MSW management to evaluate the current status of waste to energy facilities for sustainable management, which will be helpful in tackling this huge quantity of waste and the problem of energy crisis. A critical review of known MSW management practices/processes in Indian scenario, which will give an idea to investors about the market potential, the maturity of the practicing technologies, and the environmental and economical aspects was also evaluated with its advantages and disadvantages.

Identified charged hadron production in p + p collisions at √ s = 200 and 62.4 GeV

Abstract: Transverse momentum distributions and yields for pi(+/-), K-+/-, p, and (p) over bar in p + p collisions at root s = 200 and 62.4 GeV at midrapidity are measured by the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC). These data provide important baseline spectra for comparisons with identified particle spectra in heavy ion collisions at RHIC. We present the inverse slope parameter T-inv, mean transverse momentum , and yield per unit rapidity dN/dy at each energy, and compare them to other measurements at different root s in p + p and p + (p) over bar collisions. We also present the scaling properties such as m(T) scaling and x(T) scaling on the p(T) spectra between different energies. To discuss the mechanism of the particle production in p + p collisions, the measured spectra are compared to next-to-leading-order or next-to-leading-logarithmic perturbative quantum chromodynamics calculations.

Hydrogeochemistry for the assessment of groundwater quality in Varanasi: a fast-urbanizing center in Uttar Pradesh, India

Abstract: The hydrogeochemical parameters for groundwater samples of the Varanasi area, a fast-urbanizing region in India, were studied to evaluate the major ion chemistry, weathering and solute acquisition processes controlling water composition, and suitability of water quality for domestic and irrigation uses. Sixty-eight groundwater samples were collected randomly from dug wells and hand pumps in the urban Varanasi area and analyzed for various chemical parameters. Geologically, the study area comprises Quaternary alluvium made up of an alternating succession of clay, silty clay, and sand deposits. The Total dissolved solids classification reveals that except two locations, the groundwater samples are desirable for drinking, and all are useful for irrigation purposes. The cationic and anionic concentrations indicated that the majority of the groundwater samples belong to the order of Na > Ca > Mg > K and HCO3 > Cl > SO4 types, respectively. Geochemical classification of groundwater based on the Chadha rectangular diagram shows that the majority (81%) of groundwater samples belong to the calcium–bicarbonate type. The HCO3/ (HCO3 + SO4) ratio (0.87) indicates mostly carbonic acid weathering process due to presence of kankar carbonate mixed with clay/fine sand. The high nitrate concentration (>45 mg/l) of about 18% of the groundwater samples may be due to the local domestic sewage, leakage of septic tanks, and improper management of sanitary landfills. In general, the calculated values of sodium adsorption ratio, percent sodium, residual sodium carbonate, and permeability index indicate good to permissible use of water for irrigation, and only a few locations demand remedial measures for better crop yields.

Arsenite treatment induces oxidative stress, upregulates antioxidant system, and causes phytochelatin synthesis in rice seedlings

Abstract: The effects of arsenite treatment on generation of reactive oxygen species, induction of oxidative stress, response of antioxidative system, and synthesis of phytochelatins were investigated in two indica rice (Oryza sativa L.) cvs. Malviya-36 and Pant-12 grown in sand cultures for a period of 5-20 days. Arsenite (As(2)O(3); 25 and 50 μM) treatment resulted in increased formation of superoxide anion (O (2) (.-) ), elevated levels of H(2)O(2) and thiobarbituric acid reactive substances, showing enhanced lipid peroxidation. An enhanced level of ascorbate (AA) and glutathione (GSH) was observed irrespective of the variation in the level of dehydroascorbate (DHA) and oxidized glutathione (GSSG) which in turn influenced redox ratios AA/DHA and GSH/GSSG. With progressive arsenite treatment, synthesis of total acid soluble thiols and phytochelatins (PC) increased in the seedlings. Among antioxidative enzymes, the activities of superoxide dismutase (EC 1.15.1.1), catalase (EC 1.11.1.6), total ascorbate peroxidase (APX, EC 1.11.1.11), chloroplastic ascorbate peroxidase, guaiacol peroxidase (EC 1.11.1.7), monodehydroascorbate reductase (EC 1.6.5.4), and glutathione reductase (EC 1.6.4.2) increased in arsenite treated seedlings, while dehyroascorbate reductase (EC 1.8.5.1) activity declined initially during 5-10 days and increased thereafter. Results suggest that arsenite treatment causes oxidative stress in rice seedlings, increases the levels of many enzymatic and non-enzymatic antioxidants, and induces synthesis of thiols and PCs, which may serve as important components in mitigating arsenite-induced oxidative damage.

Development, characterization, conservation and storage of fish cell lines: a review

Abstract: Cell lines provide an important biological tool for carrying out investigations into physiology, virology, toxicology, carcinogenesis and transgenics Teleost fish cell lines have been developed from a broad range of tissues such as ovary, fin, swim bladder, heart, spleen, liver, eye muscle, vertebrae, brain, skin One hundred and twenty-four new fish cell lines from different fish species ranging from grouper to eel have been reported since the last review by Fryer and Lannan (J Tissue Culture Methods 16: 87–94, 1994) Among the cell lines listed, more than 60% were established from species from Asia, which contributes more than 80% of total fish production This includes 59 cell lines from 19 freshwater, 54 from 22 marine and 11 from 3 brackish water fishes Presently, about 283 cell lines have been established from finfish around the world In addition to the listing and a scientific update on new cell lines, the importance of authentication, applications, cross-contamination and implications of overpassaged cell lines has also been discussed in this comprehensive review The authors feel that the review will serve an updated database for beginners and established researchers in the field of fish cell line research and development

Advancements in solid acid catalysts for ecofriendly and economically viable synthesis of biodiesel

Abstract: Solid acid (heterogeneous) catalysts have a unique advantage in esterification and transesterification reactions which enhances the use of high acid value oil to be used as feedstock for synthesis of biodiesel. Various solid acid catalysts such as resins, tungstated and sulfated zirconia, polyaniline sulfate, heteropolyacid, metal complexes, sulfated tin oxide, zeolite, acidic ionic liquid, and others have been explored as potential heterogeneous catalysts. The activity of the catalyst differs slightly resulting in moderate to high conversion and yield. The reuse of the solid catalyst is governed by their deactivation, poisoning, and the extent of leaching in the reaction medium. The applicability of these catalysts for synthesis of biodiesel along with their reusability aspect is discussed in this review. © 2010 Society of Chemical Industry and John Wiley & Sons, Ltd

J/ψ suppression at forward rapidity in Au + Au collisions at √sNN=200 GeV

Abstract: Heavy quarkonia are observed to be suppressed in relativistic heavy-ion collisions relative to their production in p + p collisions scaled by the number of binary collisions. In order to determine if this suppression is related to color screening of these states in the produced medium, one needs to account for other nuclear modifications including those in cold nuclear matter. In this paper, we present new measurements from the PHENIX 2007 data set of J/psi yields at forward rapidity (1.2 < vertical bar y vertical bar < 2.2) in Au + Au collisions at root s(NN) = 200 GeV. The data confirm the earlier finding that the suppression of J/. at forward rapidity is stronger than at midrapidity, while also extending the measurement to finer bins in collision centrality and higher transverse momentum (p(T)). We compare the experimental data to the most recent theoretical calculations that incorporate a variety of physics mechanisms including gluon saturation, gluon shadowing, initial-state parton energy loss, cold nuclear matter breakup, color screening, and charm recombination. We find J/psi suppression beyond cold-nuclear-matter effects. However, the current level of disagreement between models and d + Au data precludes using these models to quantify the hot-nuclear-matter suppression.

Manganese-excess induces oxidative stress, lowers the pool of antioxidants and elevates activities of key antioxidative enzymes in rice seedlings

Abstract: Manganese (Mn) is an essential element for plant growth but in excess, specially in acidic soils, it can become phytotoxic. In order to investigate whether oxidative stress is associated with the expression of Mn toxicity during early seedling establishment of rice plants, we examined the changes in the level of reactive oxygen species (ROS), oxidative stress induced an alteration in the level of non-enzymic antioxidants and activities of antioxidative enzymes in rice seedlings grown in sand cultures containing 3 and 6 mM MnCl2. Mn treatment inhibited growth of rice seedlings, the metal increasingly accumulated in roots and shoots and caused damage to membranes. Mn treated plants showed increased generation of superoxide anion (O2 .−), elevated levels of H2O2 and thiobarbituric acid reactive substances (TBARS) and decline in protein thiol. The level of nonprotein thiol, however, increased due to Mn treatment. A decline in contents of reduced ascorbate (AsA) and glutathione (GSH) as well as decline in ratios of their reduced to oxidize forms was observed in Mn-treated seedlings. The activities of antioxidative enzymes superoxide dismutase (SOD) and its isoforms Mn SOD, Cu/Zn SOD, Fe SOD as well as guaiacol peroxidase (GPX) increased in the seedlings due to Mn treatment however, catalase (CAT) activity increased in 10 days old seedlings but it declined by 20 days under Mn treatment. The enzymes of Halliwell-Asada cycle, ascorbate peroxidase (APX) monodehydoascorbate reductase (MDHAR), dehyroascorbate reductase (DHAR) and glutathione reductase (GR) increased significantly in Mn treated seedlings over controls. Results suggest that in rice seedlings excess Mn induces oxidative stress, imbalances the levels of antioxidants and the antioxidative enzymes SOD, GPX, APX and GR appear to play an important role in scavenging ROS and withstanding oxidative stress induced by Mn.

A Simple, Cost-Effective Method for Leaf Area Estimation

Abstract: Easy, accurate, inexpensive, and nondestructive methods to determine individual leaf area of plants are a useful tool in physiological and agronomic studies. This paper introduces a cost-effective alternative (called here millimeter graph paper method) for standard electronic leaf area meter, using a millimeter graph paper. Investigations were carried out during August–October, 2009-2010, on 33 species, in the Botanical garden of the Banaras Hindu University at Varanasi, India. Estimates of leaf area were obtained by the equation, leaf area (cm2) = , where is the weight (g) of the area covered by the leaf outline on a millimeter graph paper, and is the weight of one cm2 of the same graph paper. These estimates were then compared with destructive measurements obtained through a leaf area meter; the two sets of estimates were significantly and linearly related with each other, and hence the millimeter graph paper method can be used for estimating leaf area in lieu of leaf area meter. The important characteristics of this cost-efficient technique are its easiness and suitability for precise, non-destructive estimates. This model can estimate accurately the leaf area of plants in many experiments without the use of any expensive instruments.

Serial Quantitative PCR Assay for Detection, Species Discrimination, and Quantification of Leishmania spp. in Human Samples

Abstract: The invention provides a method for determining the presence, species, and/or quantity of Leishmania in a sample.

Antidiabetic and in vitro antioxidant potential of Hybanthus enneaspermus (Linn) F. Muell in streptozotocin-induced diabetic rats.

Abstract: Objective To evaluate antidiabetic and antioxidant potential of Hybanthus enneaspermus in different models.

Inhibitive Effect of Argemone mexicana Plant Extract on Acid Corrosion of Mild Steel

Abstract: The effect of plant extract of Papaveraceae family Argemone mexicana is studied for use as a low cost and efficient corrosion inhibitor for mild steel in acidic environment. This plant extract is selected for the study of corrosion inhibition in view of its rich source of organic inhibiting molecules as proteins, amino acids, tannins, phenolic compounds, saponins, and flavonoids and nonalkaloids organic compounds such as fused benzene rings, hetero N atom rings, −OCH3, and −OH groups. A simple extraction method is adopted to obtain water-based plant extract. Argemone mexicana extract is for the first time used as an efficient inhibitor for mild steel in 1 M HCl. Weight loss and electrochemical methods are used to study the corrosion. Nearly 80% corrosion inhibition is observed at around 200 mg L–1 inhibitor concentration and maximum (92.5%) for 500 mg L–1 extract concentration in 1 M HCl. Inhibition mechanism is studied using UV–vis, electrochemical, and surface imaging techniques.

Shared and Unique Components of Human Population Structure and Genome-Wide Signals of Positive Selection in South Asia

Abstract: South Asia harbors one of the highest levels genetic diversity in Eurasia, which could be interpreted as a result of its long-term large effective population size and of admixture during its complex demographic history. In contrast to Pakistani populations, populations of Indian origin have been underrepresented in previous genomic scans of positive selection and population structure. Here we report data for more than 600,000 SNP markers genotyped in 142 samples from 30 ethnic groups in India. Combining our results with other available genome-wide data, we show that Indian populations are characterized by two major ancestry components, one of which is spread at comparable frequency and haplotype diversity in populations of South and West Asia and the Caucasus. The second component is more restricted to South Asia and accounts for more than 50% of the ancestry in Indian populations. Haplotype diversity associated with these South Asian ancestry components is significantly higher than that of the components dominating the West Eurasian ancestry palette. Modeling of the observed haplotype diversities suggests that both Indian ancestry components are older than the purported Indo-Aryan invasion 3,500 YBP. Consistent with the results of pairwise genetic distances among world regions, Indians share more ancestry signals with West than with East Eurasians. However, compared to Pakistani populations, a higher proportion of their genes show regionally specific signals of high haplotype homozygosity. Among such candidates of positive selection in India are MSTN and DOK5, both of which have potential implications in lipid metabolism and the etiology of type 2 diabetes.

Electrochemical Detection of Uric Acid in Mixed and Clinical Samples: A Review

Abstract: The present review has sought to explore the technological advances that have been made in recent years towards the selective analysis of uric acid and critically evaluate how they could, in fact, be exploited as a basis for a multi analyte sensor incorporating uric acid detection Numerous strategies have evolved in recent years but these have invariably focused on the manufacture and response characterization of discrete sensors Various methods of obtaining selective detection such as use of uricase enzymes, nanoparticles, carbon nanotubes, polymers, conducting polymers and MIPs are also discussed along with the clinical relevance of UA determination

Protective Role of Ashwagandha Leaf Extract and Its Component Withanone on Scopolamine-Induced Changes in the Brain and Brain-Derived Cells

Abstract: Background Scopolamine is a well-known cholinergic antagonist that causes amnesia in human and animal models. Scopolamine-induced amnesia in rodent models has been widely used to understand the molecular, biochemical, behavioral changes, and to delineate therapeutic targets of memory impairment. Although this has been linked to the decrease in central cholinergic neuronal activity following the blockade of muscarinic receptors, the underlying molecular and cellular mechanism(s) particularly the effect on neuroplasticity remains elusive. In the present study, we have investigated (i) the effects of scopolamine on the molecules involved in neuronal and glial plasticity both in vivo and in vitro and (ii) their recovery by alcoholic extract of Ashwagandha leaves (i-Extract).

Luminescence properties of Eu3+ doped CaMoO4 nanoparticles

Abstract: When Eu3+ ions occupy Ca2+ sites of CaMoO4, which has a body centered tetragonal structure with inversion symmetry, only the magnetic dipole transition (5D0→7F1) should be allowed according to Judd–Ofelt theory. Even if there are a few distortions in the Eu3+ environment, its intensity should be more than that of the electric dipole transition (5D0→7F2). We report here the opposite effect experimentally and ascribe this to the polarizability effect of the MoO4 tetrahedron, which is neighboring to EuO8 (symmetric environment). The contribution of the energy transfer process from the Mo–O charge transfer band to Eu3+ and the role of Eu3+ over the surface of the particle could be distinguished when luminescence decay processes were measured at two different excitations (250 and 398 nm). Further, the luminescence intensities and lifetimes increase significantly with increasing heat-treatment temperature of the doped samples. This is attributed to the reduction of H2O from the surface of the particles and a non-radiative process after heat treatment.

Incidence of symptomatic and asymptomatic Leishmania donovani infections in high-endemic foci in India and Nepal: a prospective study

Abstract: Incidence of Leishmania donovani infection and Visceral Leishmaniasis (VL) was assessed in a prospective study in Indian and Nepalese high-endemic villages. DAT-seroconversion was used as marker of incident infection in 3 yearly surveys. The study population was followed up to month 30 to identify incident clinical cases. In a cohort of 9034 DAT-negative individuals with neither active signs nor history of VL at baseline, 42 VL cases and 375 asymptomatic seroconversions were recorded in the first year, giving an infection:disease ratio of 8.9 to 1. In the 18 months' follow-up, 7 extra cases of VL were observed in the seroconverters group (N=375), against 14 VL cases among the individuals who had not seroconverted in the first year (N=8570) (RR=11.5(4.5