1,053 research outputs found

    Biological and materials properties of various cholesterol based systems

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    Liposomes composed of cationic lipids have become very popular gene delivery vehicles. A great deal of research is being pursued to make efficient vectors by varying their molecular architecture. Cholesterol being ubiquitous component in most of the animal cell membranes is increasingly being used as a hydrophobic segment of synthetic cationic lipids. In this review we describe various cholesterol based cationic lipids and focus on the effect of modifying various structural segments like linker and the head group of the cationic lipids on gene transfection efficiency with a special emphasis on the importance of ether linkage between cholesteryl backbone and the polar head group. Interaction of cationic cholesteryl lipids with dipalmitylphosphatidycholine membranes is also discussed here. Apart from cholesterol being an attractive scaffold in the drug/gene delivery vehicles, certain cholesteryl derivatives have also been shown to be attractive room temperature liquid-crystalline materials

    Numerical Simulation of a Nano-pulsed High-voltage Discharge and Impact on Low-temperature Plasma Ignition Processes for Automotive Applications

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    Spark-ignition (SI) processes are facing some challenges with the SI engine research continuing to move towards extremely dilute operation. Typical response from the automotive OEMs is to increase the spark energy to hundreds of mJs. However, this approach reduces the spark-plug lifetime due to erosion. In recent years, several lowtemperature plasma (LTP) technologies (e.g. microwave, nanosecond pulsed discharge, Corona discharge) have been proposed for automotive applications as a substitute for the conventional SI process, yet no LTP ignition models are available for commercial computational fluid dynamics (CFD) codes for the evaluation and optimization of these advanced ignition systems. This paper summarizes recent efforts to model LTP generated by a nano-pulsed highvoltage discharge in a multi-dimensional fashion. Streamer discharges between two pin electrodes are modeled through 2-D computations using the non-equilibrium plasma commercial solver VizGlow. The impact of key parameters such as peak voltage and gas density on the characteristics of the streamers is evaluated. The experimental dataset is used to validate the numerical predictions in terms of thermal and chemical properties of the generated plasma at the end of the discharge. Then, the impact of the post-discharge characteristics on the LTP ignition process is evaluated in combustion simulations performed using the CFD code CONVERGE

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    Not AvailableSundarban area of West Bengal State in India is a complex-diverse-risk prone agro-ecosystem grappled with degraded soil, water logging, brackish ground water and marginal farm holdings. South west monsoon rain-fed paddy crop is the major production system and the farm families have to migrate to other areas for employment during the post-monsoon season. Farm pond based rain water harvesting and optimally utilizing it to cultivate vegetables and rearing fish in the pond would provide them employment, income and self-reliance on a sustainable basis is the solution. Rain water harvesting based production system models namely, land shaping for aqua-agri integration, brackishwater pond based polyculture and paddy-cum-fish farming were implemented to 370 beneficiary families to enhance the livelihood security at Kakdwip and Namkhana blocks of South 24 Parganas district of West Bengal. A set of 15 indicators were identified by the subject matter scientists to assess the outcome of the interventions in enhancing the livelihood security of farm families. Impact analysis was done using ‘before vs after’ and control vs treatment research design. Primary data were collected from the sample of 120 proportionate random sample beneficiary farm families using a structured questionnaire and focus group meetings. The findings substantially indicated that all the three farming models have contributed for enhancing the livelihood security levels of the farm families in terms of creation of livelihood asset mainly the farm pond, conservation of natural water for multiple cropping and aquaculture, enhanced capabilities, employment generation, improved production from the land/pond, enhanced income from farming, access to better market price, access to development institutions, minimization of migration during off-season, enhanced self-reliant, and social status of the farm families. The analyses have confirmed that all the three farming models have significantly contributed for the livelihood security of the coastal farm families (p<0.01). Therefore, the study suggested that the Government may evolve a scheme with inbuilt subsidy in up-scaling these models in the entire Sundarban region for enhancing the livelihood security of farm families.Not Availabl

    Inhibitory Potential of Chromene Derivatives on Structural and Non-Structural Proteins of Dengue Virus

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    Dengue fever is a mosquito-borne viral disease that has become a serious health issue across the globe. It is caused by a virus of the Flaviviridae family, and it comprises five different serotypes (DENV-1 to DENV-5). As there is no specific medicine or effective vaccine for controlling dengue fever, there is an urgent need to develop potential inhibitors against it. Traditionally, various natural products have been used to manage dengue fever and its co-morbid conditions. A detailed analysis of these plants revealed the presence of various chromene derivatives as the major phytochemicals. Inspired by these observations, authors have critically analyzed the anti-dengue virus potential of various 4H chromene derivatives. Further, in silico, in vitro, and in vivo reports of these scaffolds against the dengue virus are detailed in the present manuscript. These analogues exerted their activity by interfering with various stages of viral entry, assembly, and replications. Moreover, these analogues mainly target envelope protein, NS2B-NS3 protease, and NS5 RNA-dependent RNA polymerase, etc. Overall, chromene-containing analogues exerted a potent activity against the dengue virus and the present review will be helpful for the further exploration of these scaffolds for the development of novel antiviral drug candidates

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    Antibacterial efficacy of Jackfruit rag extract against clinically important pathogens and validation of its antimicrobial activity in Shigella dysenteriae infected Drosophila melanogaster infection model

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    513-522Exploration of alternative sources of antibacterial compounds is an important and possibly an effective solution to the current challenges in antimicrobial therapy. Plant derived wastes may offer one such alternative. Here, we investigated the antibacterial property of extract derived from a part of the Jackfruit (Artocarpus heterophyllus Lam.) called ‘rag’, generally considered as fruit waste. Morpho-physical characterization of the Jackfruit rag extract (JFRE) was performed using Gas-chromatography, where peaks indicative of furfural; pentanoic acid; and hexadecanoic acid were observed. In vitro biocompatibility of JFRE was performed using the MTT assay, which showed comparable cellular viability between extract-treated and untreated mouse fibroblast cells. Agar well disc diffusion assay exhibited JFRE induced zones of inhibition for a wide variety of laboratory and clinical strains of Gram-positive and Gram-negative bacteria. Analysis of electron microscope images of bacterial cells suggests that JFRE induces cell death by disintegration of the bacterial cell wall and precipitating intracytoplasmic clumping. The antibacterial activity of the JFREs was further validated in vivo using Shigella dysenteriae infected fly model, where JFRE pre-fed flies infected with S. dysenteriae had significantly reduced mortality compared to controls. JFRE demonstrates broad antibacterial property, both in vitro and in vivo, possibly by its activity on bacterial cell wall

    Linking Distributive and Procedural Justice to Employee Engagement Through Social Exchange: A Field Study in India

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    Research linking justice perceptions to employee outcomes has referred to social exchange as its central theoretical premise. We tested a conceptual model linking distributive and procedural justice to employee engagement through social exchange mediators, namely, perceived organizational support and psychological contract, among 238 managers and executives from manufacturing and service sector firms in India. Findings suggest that perceived organizational support mediated the relationship between distributive justice and employee engagement, and both perceived organizational support and psychological contract mediated the relationship between procedural justice and employee engagement. Theoretical and practical implications with respect to organizational functions are discussed

    Limits on WWZ and WW\gamma couplings from p\bar{p}\to e\nu jj X events at \sqrt{s} = 1.8 TeV

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    We present limits on anomalous WWZ and WW-gamma couplings from a search for WW and WZ production in p-bar p collisions at sqrt(s)=1.8 TeV. We use p-bar p -> e-nu jjX events recorded with the D0 detector at the Fermilab Tevatron Collider during the 1992-1995 run. The data sample corresponds to an integrated luminosity of 96.0+-5.1 pb^(-1). Assuming identical WWZ and WW-gamma coupling parameters, the 95% CL limits on the CP-conserving couplings are -0.33<lambda<0.36 (Delta-kappa=0) and -0.43<Delta-kappa<0.59 (lambda=0), for a form factor scale Lambda = 2.0 TeV. Limits based on other assumptions are also presented.Comment: 11 pages, 2 figures, 2 table

    Search For Heavy Pointlike Dirac Monopoles

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    We have searched for central production of a pair of photons with high transverse energies in ppˉp\bar p collisions at s=1.8\sqrt{s} = 1.8 TeV using 70pb170 pb^{-1} of data collected with the D\O detector at the Fermilab Tevatron in 1994--1996. If they exist, virtual heavy pointlike Dirac monopoles could rescatter pairs of nearly real photons into this final state via a box diagram. We observe no excess of events above background, and set lower 95% C.L. limits of 610,870,or1580GeV/c2610, 870, or 1580 GeV/c^2 on the mass of a spin 0, 1/2, or 1 Dirac monopole.Comment: 12 pages, 4 figure
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