Showing papers by "Banaras Hindu University published in 2003"

Elliptic flow of identified hadrons in [formula presented] collisions at [formula presented]

Abstract: The anisotropy parameter (v(2)), the second harmonic of the azimuthal particle distribution, has been measured with the PHENIX detector in Au+Au collisions at roots(NN)=200 GeV for identified and inclusive charged particle production at central rapidities (eta 2 GeV/c, in marked contrast to the predictions of a hydrodynamical model. A quark-coalescence model is also investigated.

Suppressed π0 Production at Large Transverse Momentum in Central Au + Au Collisions at √sNN = 200 GeV

Abstract: Transverse momentum spectra of neutral pions in the range 1 < p_T < 10 GeV/c have been measured at mid-rapidity by the PHENIX experiment at RHIC in Au+Au collisions at sqrt(s_NN) = 200 GeV. The pi^0 multiplicity in central reactions is significantly below the yields measured at the same sqrt(s_NN) in peripheral Au+Au and p+p reactions scaled by the number of nucleon-nucleon collisions. For the most central bin, the suppression factor is ~2.5 at p_T = 2 GeV/c and increases to ~4-5 at p_T ~= 4 GeV/c. At larger p_T, the suppression remains constant within errors. The deficit is already apparent in semi-peripheral reactions and increases smoothly with centrality.

PHENIX detector overview

Abstract: The PHENIX detector is designed to perform a broad study of A-A, p-A, and p-p collisions to investigate nuclear matter under extreme conditions A wide variety of probes, sensitive to all timescales, are used to study systematic variations with species and energy as well as to measure the spin structure of the nucleon Designing for the needs of the heavy-ion and polarized-proton programs has produced a detector with unparalleled capabilities PHENIX measures electron and muon pairs, photons, and hadrons with excellent energy and momentum resolution The detector consists of a large number of subsystems that are discussed in other papers in this volume The overall design parameters of the detector are presented (C) 2002 Elsevier Science BV All rights reserved

Evidence for MB and MC phases in the morphotropic phase boundary region of (1-x)[Pb(Mg1/3Nb2/3)O3]-xPbTiO3: A Rietveld study

Abstract: We present here the results of the room-temperature dielectric measurements and Rietveld analysis of the powder x-ray diffraction data on $(1\ensuremath{-}x)[\mathrm{Pb}({\mathrm{Mg}}_{1/3}{\mathrm{Nb}}_{2/3}){\mathrm{O}}_{3}]\ensuremath{-}x{\mathrm{PbTiO}}_{3}(\mathrm{PMN}\ensuremath{-}x\mathrm{PT})$ in the composition range $0.20l~xl~0.45$ to show that the morphotropic phase boundary region contains two monoclinic phases with space groups Cm (or ${M}_{B}$ type) and Pm (or ${M}_{C}$ type) stable in the composition ranges $0.27l~xl~0.30$ and $0.31l~xl~0.34,$ respectively. The structure of $\mathrm{PMN}\ensuremath{-}x\mathrm{PT}$ in the composition ranges $0l~xl~0.26$ and $0.35l~xl~1$ is found to be rhombohedral (R3m) and tetragonal (P4mm), respectively. These results are compared with the predictions of Vanderbilt Cohen's theory.

Effect of standard heat treatment on the microstructure and mechanical properties of hot isostatically pressed superalloy inconel 718

Abstract: Ni–Fe base superalloy, Inconel 718, was processed through powder metallurgy (P/M) hot isostatic pressing (HIP) route. In order to balance the strength and ductility, the HIPed material was given the standard heat treatment, viz. solution treatment at 980 °C for 1 h/water quenched (WQ) to room temperature and a two-step ageing treatment consisting of 720 °C for 8 h/furnace cooling (FC) at 55 °C h−1 to 620 °C and holding at 620 °C for 8 h before air cooling (AC) to room temperature. Optical microscopy and scanning electron microscopy (SEM) studies on the heat treated alloy have shown a homogeneous microstructure with fine grain size (25 μm) along with the presence of prior particle boundary (PPB) networks. Transmission electron microscopy (TEM) on the heat treated material has revealed the presence of oxides, MC carbides and δ-precipitates at the grain boundaries and a uniform precipitation of fine γ″ and γ′ strengthening phases in the matrix. Tensile and stress rupture tests were performed on the heat treated material. While the yield strength (YS) and ultimate tensile strength (UTS) of the HIPed and heat treated alloy at room temperature and 650 °C were comparable to those of conventionally processed wrought IN 718, its ductility was lower. The stress rupture life of the HIPed alloy improved marginally due to heat treatment and met the minimum specification requirement of life hours but the rupture ductility was found to be inferior to that of the wrought material. The fractography of the failed samples has revealed the transgranular ductile mode of fracture in the as-solution treated alloy, while intergranular mode of failure with the decohesion of PPBs occurred more predominantly in the aged condition. This change of fracture mode with ageing treatment shows the ductility dependence on the relative strength of the matrix and PPBs. The TEM studies on the deformed alloy have revealed that the brittle oxides and carbides at the prior particle boundaries coupled with the fine γ″ and γ′-precipitates in the matrix are responsible for low ductility at 650 °C. The investigations of the present study have led to better understanding of the structure–property relationships in HIP+heat treated alloy 718 and suggest that the standard heat treatment recommended for wrought IN 718 is not suitable for HIPed alloy and has to be modified to realise optimum properties.

Midrapidity Neutral-Pion Production in Proton-Proton Collisions at √s = 200 GeV

Abstract: The invariant differential cross section for inclusive neutral-pion production in p+p collisions at roots=200 GeV has been measured at midrapidity (eta<0.35) over the range 1

Scaling Properties of Proton and Antiproton Production in √S NN = 200 GeV Au + Au Collisions

Abstract: We report on the yield of protons and antiprotons, as a function of centrality and transverse momentum, in Au+Au collisions at rootS(NN)=200 GeV measured at midrapidity by the PHENIX experiment at the BNL Relativistic Heavy Ion Collider. In central collisions at intermediate transverse momenta (1.5

In vitro and in vivo evaluation of the Gelrite gellan gum-based ocular delivery system for indomethacin.

Abstract: The poor bioavailability and therapeutic response exhibited by the conventional ophthalmic solutions due to pre-corneal elimination of the drug may be overcome by the use of in situ gel forming systems, which upon instillation as drops into the eye undergo a sol-gel transition in the cul-de-sac. This may result in better ocular availability of the drug. The purpose of this work was to develop an ophthalmic delivery system of the NSAID indomethacin, based on the concept of ion activated in situ gelation. Gelrite gellan gum, a novel ophthalmic vehicle, which gels in the presence of mono or divalent cations present in the lacrimal fluid, was used as the gelling agent. The developed formulations were therapeutically efficacious (in a uveitis induced rabbit eye model) and provided sustained release of the drug over an 8-hour period in vitro.

Technological aspects of extractive fermentation using aqueous two-phase systems

Abstract: The efficiency of any fermentation process depends largely on downstream processing which ensures the purity and quality of the biochemicals. Since many biomolecules have narrow tolerance limits of pH, temperature, osmotic pressure, surface charges, etc. the extraction and isolation techniques should be specific and compatible to the product. Therefore, it is not surprising that about 60-90% of the cost of a biological process is that expended on downstream processing. Aqueous two-phase systems (ATPS) result from the incompatibility or immiscibility of polymers, either between two polymers in water or a polymer solution with a salt solution. ATPS contain about 80-90% water and thereby can provide an excellent environment for cells, cell organelles and biologically active substances. 'Extractive fermentation' is an emerging technique that involves the use of ATPS-based in situ fermentation processes. The advantages of such a system include rapid mass transfer due to low-interfacial tension, ease of operation under continuous mode, rapid and selective separation, biocompatibility, separation at room temperature, easy and reliable scale-up of bench scale results to production scale, ecofriendliness, suitability for systems with product inhibition and high yield of biomolecules. In this review, we will consider the basic principles involved and factors affecting extractive fermentation, technical aspects and technological developments like use of ligands and surfactants to improve separation, recent trends and future prospects of extractive fermentation systems. This review will also focus on the parameters responsible for better separation for in situ fermentation.

Single-dose liposomal amphotericin B in the treatment of visceral leishmaniasis in India: a multicenter study.

Abstract: Widespread antimony resistance renders conventional amphotericin B the only option for the treatment of visceral leishmaniasis (VL) in North Bihar, India. Because of its excellent safety profile, a large dose (7.5 mg/kg) of liposomal amphotericin B (L-AmB) was given to each of 203 patients with VL at 4 treatment centers, and the patients were discharged the next day. At initial clinical and parasitological follow-up, performed on day 30 after treatment, evidence of a cure was seen in 195 (96%) of 203 patients (95% CI, 92-98); 4 patients experienced treatment failure. Two patients were lost to follow-up, 2 died (one due to progressive disease and another, 5 months after treatment, due to an unrelated illness), and 12 experienced relapses during follow-up. Thus, 183 patients (90%; 95% CI, 85-94) had obtained final cure 6 months after treatment. Very few adverse events (fever with rigor, in 9.8% of patients) were seen. Single-dose L-AmB (7.5 mg/kg) treatment is safe and effective, and it may be used for the mass treatment of VL in India.

UV-B-induced synthesis of mycosporine-like amino acids in three strains of Nodularia (cyanobacteria).

Abstract: Three filamentous and heterocystous cyanobacterial strains of Nodularia, Nodularia baltica, Nodularia harveyana and Nodularia spumigena, have been tested for the presence and induction of ultraviolet-absorbing/screening mycosporine-like amino acids (MAAs) by simulated solar radiation in combination with 395 (receiving photosynthetically active radiation (PAR) only), 320 (receiving PAR + UV-A) and 295 (receiving PAR + UV-A + UV-B) nm cut-off filters. Absorption spectroscopic analyses of the methanolic extracts of samples revealed a typical MAA peak at 334 nm in all three cyanobacteria. Specific contents of MAAs had a pronounced induction in the samples covered with 295 nm cut-off filters after 72 h of irradiation. In comparison, there was little induction of MAAs in the samples covered by 395 and 320 nm cut-off filters. High performance liquid chromatographic (HPLC) studies revealed the presence of two types of MAAs in all three cyanobacteria, which were identified as shinorine and porphyra-334, both absorbing maximally at 334 nm. The occurrence of porphyra-334 is rare in cyanobacteria. Specific content of both shinorine and porphyra-334 were induced remarkably only in the samples covered with 295 nm cut-off filters. The results indicate that in comparison to UV-A and PAR, UV-B is more effective in eliciting MAAs induction in the studied cyanobacteria.

Sodium Alginate Microspheres of Metoprolol Tartrate for Intranasal Systemic Delivery: Development and Evaluation

Abstract: Bioadhesive sodium alginate microspheres of Metoprolol tartrate (MT) for intranasal systemic delivery were prepared to avoid the first-pass effect, as an alternative therapy to injection, and to ob

Oral miltefosine treatment in children with mild to moderate Indian visceral leishmaniasis.

Abstract: BACKGROUND: Miltefosine is the first oral drug with demonstrable success in treating visceral leishmaniasis in adults. Because approximately one-half of the visceral leishmaniasis patients worldwide are children, we performed a Phase I/II dose ranging study in the pediatric population in India. METHODS: Thirty-nine (39) children (defined as < 12 years of age) with visceral leishmaniasis demonstrated by parasites in splenic aspirates, were treated with oral miltefosine daily for 28 days: 21 patients received 1.5 mg/kg/day (Group A); and 18 patients received 2.5 mg/kg/day (Group B). About one-half of these children had failed prior antileishmanial treatment. RESULTS: All patients were parasitologically negative and symptomatically improved by the end of therapy on Day 28 of therapy; the initial parasitologic cure rate was 100%. Two patients in each treatment group relapsed with fever, splenomegaly and parasite-positive splenic aspirates by the end of the 6-month follow-up. The per protocol final clinical cure rate was 19 of 21 = 90% in Group A and 15 of 17 = 88% in Group B. Miltefosine was well-tolerated. As per the adult experience, gastrointestinal adverse events were seen: 33 and 39% of children experienced vomiting and 5 and 17% experienced diarrhea in Groups A and B, respectively, but all episodes were mild to moderate in severity and commonly lasted <1 day without symptomatic treatment. CONCLUSION: Oral miltefosine was safe and approximately 90% effective in this initial clinical trial of childhood visceral leishmaniasis.

Synthesis of Nanosized and Microporous Precipitated Hydroxyapatite in Synthetic Polymers and Biopolymers

Abstract: In situ precipitation of microporous and nanosized hydroxyapatite particles (5-40 nm) has been conducted in poly(vinyl alcohol) and bovine serum albumin gels. The process, which is similar to biomineralization, is highly controlled with respect to microstructural features, such as size and shape, and to precipitation of hydroxyapatite phase having a calcium:phosphorus stoichiometric ratio of 1.67. Nanosized precipitated hydroxyapatite particles show remarkable thermal stability and do not decompose to other calcium phosphate phases, even at higher temperatures.

Dairy Effluent Polishing by Aquatic Macrophytes

Abstract: In dairy industry, primary and secondary treatmentmethods are quite common for effluent treatment. However,this type of treatment is not effective in filtering thenutrients from the dairy waste water. Nutrient removalcapacity of some important macrophytes i.e. Eichhorniacrassipes, Lemna minor and Azolla pinnata have beentested individually as well as in combinations undermicrocosm investigations. Percentage nitrogen removal valuesby E.crassipes, A.pinnata and L. minor were 71.8 ± 0.20, 62.5 ± 0.39 and 60.13 ± 0.48.Corresponding figures for phosphorus were 63.2 ± 0.98,58.8 ± 0.57 and 56.3 ± 0.51. Maximum removal wasobserved in combination studies, involving E. crassipesand L. minor (78.8 ± 0.18% nitrogen and69.4 ± 0.11% phosphorus). Analysis of variance revealedsignificant (p < 0.001) variation among different incubationperiods, both for nitrogen (F = 395985) and phosphorus (F =196767) removal by a combination of E. crassipes, andL. minor. E. crassipes and A. pinnata removed74.1 ± 0.11% of nitrogen and 68.7 ± 1.0% ofphosphorus, whereas, it was recorded 70.0 ± 0.25%nitrogen and 66.7 ± 0.95% phosphorus by combination ofL. minor and A. pinnata.

Ecology, language, and performance on spatial cognitive tasks

Abstract: The study of the orientation systems that people use in different cultures to describe the location of objects in space has drawn some interest of researchers in the fields of anthropology, psycholinguistics, and cognitive psychology. There has been a rethinking of the “linguistic relativity hypothesis,” and some empirical studies tend to support the notion that language is the major determinant of encoding and cognitive performance on spatial tasks. This paper reports a crosscultural study carried out with 545 children aged 4 to 14 years, both schooled and unschooled, in India and Nepal. The field sites were selected taking into consideration how reference to spatial locations is organized in the language as well as in the local cultural practices. In a village near Varanansi in India, people organize spatial locations mainly with reference to cardinal directions, but in the city of Varanasi, relative references are also used, although people in both the locations speak the same language (i.e., Hindi). I...

Ion-activated in situ gelling systems for sustained ophthalmic delivery of ciprofloxacin hydrochloride.

Abstract: The poor bioavailability and therapeutic response exhibited by the conventional ophthalmic solutions due to precorneal elimination of the drug may be overcome by the use of in situ gel forming systems that are instilled as drops into the eye and undergo a sol-gel transition in the cul-de-sac. Our present work describes the formulation and evaluation of an ophthalmic delivery system of an antibacterial agent, CPH, based on the concept of ion-activated in situ gelation. Gelrite gellan gum, a novel ophthalmic vehicle that gels in the presence of mono or divalent cations, present in the lacrimal fluid was used alone and in combinations with sodium alginate as the gelling agent. The developed formulations were therapeutically efficacious and provided sustained release of the drug over an 8-hr period in vitro.

Wavelength-dependent induction of a mycosporine-like amino acid in a rice-field cyanobacterium, Nostoc commune: role of inhibitors and salt stress

Abstract: Wavelength-dependent induction of a mycosporine-like amino acid (MAA) was studied in a nitrogen-fixing rice-field cyanobacterium, Nostoc commune. HPLC studies showed the presence of shinorine, a bisubstituted MAA containing both glycine and serine groups and having an absorption maximum at 334 nm. Exposure of cultures to simulated solar radiation in combination with various cut-off filters (WG 280, 295, 305, 320, 335, 345, GG 400, 420, 455, 475, OG 515, 530, 570, RG 645, 665; all Schott filter series) clearly indicated that MAAs were induced by UV-B radiation, while UV-A and PAR had very little effect on MAA induction in this organism. The ratio of the absorption at 334 nm (shinorine) to 665 nm (chlorophyll a) and the derived action spectrum also revealed the induction of MAAs to be UV-B dependent with a prominent peak at 290 nm and a second small peak at 310 nm. Various concentrations (50–300 mM) of NaCl were used to test whether another common stress factor, such as osmotic stress, also induces MAAs, as has been reported for other cyanobacterial species. The results indicate that cells grown at high concentration of NaCl but without UV-B did not show any MAA induction. In order to elucidate the possible photoreceptors, the effects of various inhibitors/quenchers on the induction of MAAs were studied. There was a marked reduction in the amount of MAA when the cells were irradiated with UV-B in the presence of inhibitors of the shikimate pathway (glyphosate, 1 mM), photosynthesis [3-(3,4-dichlorophenyl)-1,1-dimethylurea, 20 µM], protein synthesis (chloramphenicol, 25 µg ml−1), pterin synthesis (N-acetylserotonin, 5 mM, and 2,4-diamino-6-hydroxypyrimidine, 5 mM) and a quencher of the excited state of flavins and pterins (phenylacetic acid, 1 mM).