55 research outputs found

    Spatio-Temporal Dynamics of Caddisflies in Streams of Southern Western Ghats

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    The dynamics of physico-chemical factors and their effects on caddisfly communities were examined in 29 streams of southern Western Ghats. Monthly samples were collected from the Thadaganachiamman stream of Sirumalai Hills, Tamil Nadu from May 2006 to April 2007. Southwest and northeast monsoons favored the existence of caddisfly population in streams. A total of 20 caddisfly taxa were collected from 29 streams of southern Western Ghats. Hydropsyche (Trichoptera: Hydropsychidae) were more widely distributed throughout sampling sites than were the other taxa. Canonical correspondence analysis showed that elevation was a major variable and pH, stream order, and stream substrates were minor variables affecting taxa richness. These results suggested that habitat heterogeneity and seasonal changes were stronger predictors of caddisfly assemblages than large-scale patterns in landscape diversity

    Optimization of TAM16, a Benzofuran That Inhibits the Thioesterase Activity of Pks13; Evaluation toward a Preclinical Candidate for a Novel Antituberculosis Clinical Target

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    [Image: see text] With increasing drug resistance in tuberculosis (TB) patient populations, there is an urgent need for new drugs. Ideally, new agents should work through novel targets so that they are unencumbered by preexisting clinical resistance to current treatments. Benzofuran 1 was identified as a potential lead for TB inhibiting a novel target, the thioesterase domain of Pks13. Although, having promising activity against Mycobacterium tuberculosis, its main liability was inhibition of the hERG cardiac ion channel. This article describes the optimization of the series toward a preclinical candidate. Despite improvements in the hERG liability in vitro, when new compounds were assessed in ex vivo cardiotoxicity models, they still induced cardiac irregularities. Further series development was stopped because of concerns around an insufficient safety window. However, the demonstration of in vivo activity for multiple series members further validates Pks13 as an attractive novel target for antitubercular drugs and supports development of alternative chemotypes

    Altitudinal variation in soil organic carbon stock in coniferous subtropical and broadleaf temperate forests in Garhwal Himalaya

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    <p>Abstract</p> <p>Background</p> <p>The Himalayan zones, with dense forest vegetation, cover a fifth part of India and store a third part of the country reserves of soil organic carbon (SOC). However, the details of altitudinal distribution of these carbon stocks, which are vulnerable to forest management and climate change impacts, are not well known.</p> <p>Results</p> <p>This article reports the results of measuring the stocks of SOC along altitudinal gradients. The study was carried out in the coniferous subtropical and broadleaf temperate forests of Garhwal Himalaya. The stocks of SOC were found to be decreasing with altitude: from 185.6 to 160.8 t C ha<sup>-1 </sup>and from 141.6 to 124.8 t C ha<sup>-1 </sup>in temperature (<it>Quercus leucotrichophora</it>) and subtropical (<it>Pinus roxburghii</it>) forests, respectively.</p> <p>Conclusion</p> <p>The results of this study lead to conclusion that the ability of soil to stabilize soil organic matter depends negatively on altitude and call for comprehensive theoretical explanation</p

    Investigations of crystalline and optical perfection of SHG oriented KDP crystals

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    Potassium dihydrogen phosphate (KDP) crystals grown along the type-II phase-matching direction were investigated for crystalline and optical perfection. Highresolution X-ray diffraction (HRXRD) technique was used for investigating crystalline perfection. UV–VIS transmission, Mach–Zehnder interferometry, birefringence interferometry and conoscopy were performed for optical characterization. HRXRD results show that the grown crystals have good structural perfection. A uniform transmittance of 92% was observed in the visible region of the spectrum. Straight and parallel fringes were observed in Mach–Zehnder interferometric studies. A symmetrical fringe pattern was obtained in conoscopy images. These interferometric results suggest that the optical homogeneity of the grown crystal was good and not influenced by the growth techniqu

    Determination of crystalline perfection, optical indicatrix, birefringence and refractive-index homogeneity of ZTS crystals

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    Single crystals of the semi-organic non-linear optical material zinc tris (thiourea) sulphate (ZTS) were grown by slow evaporation solution growth technique. The crystals were characterized for crystalline perfection and optical homogeneity using high-resolution X-ray diffraction (HRXRD) and optical interferometric techniques. The FWHM of 6 arc sec in HRXRD rocking curve shows the good crystalline quality. Transmittance of ∼75% shows that the crystal is free from volume defects. Conoscopy was used to assess the optical quality and investigate the optical indicatrix of the grown crystal. Birefringence values of the crystal along the three principal crystallographic axes were measured using birefringence interferometry. Mach–Zehnder interferograms exhibit good refractive-index homogeneity of the grown crystal

    Soft-shell crab production using hatchery-produced mangrove crab Scylla serrata juveniles

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    Soft-shell crab production is being practiced in many Asian countries but the major source of seedstock is from the wild, which could no longer sustain the increasing demand. Commercial scale soft-shell crab production can become sustainable only if there is a continuous supply of seedstock not dependent on wild stock. Rajiv Gandhi Centre for Aquaculture (RGCA) under the Marine Products Export Development Authority (MPEDA) has established a pilot-scale mud crab hatchery at Thoduvai, Nagapattinam District, Tamilnadu in 2004 with the technical assistance from SEAFDEC/AQD. At present, RGCA has the biggest mud crab hatchery in India and a demonstration farm at Karaikal, U.T. of Puducherry, where nursery rearing, grow-out and soft-shell crab production are conducted using hatchery- produced mangrove crabs or mud crabs, Scylla serrata. This paper presents the results of the soft-shell crab production using hatcheryproduced S. serrata juveniles maintained in perforated low density polyethylene (LDPE) boxes. The duration of the molt interval, time of molt (day or night) and the increase in body weight and carapace width of each size group (40-60, 61-80, 81-100, 101-120, 121-140, 141-160, 161-180 g) after molting were determined. Results showed that the percentage increase in body weight and carapace width increased as the crabs grew bigger. Likewise, the molt interval was longer in bigger-sized groups of crabs. Sixty to seventy percent of the population molted during night time and the next molt occurred within 25 days in 80-160 g size groups. Soft-shell crabs in boxes within the water surface and juvenile crabs (2.5 cm CW initial size) for culture until market size in the pond can be a viable technology technology for mud crab growers

    Crystalline perfection, spectroscopic investigations and transport properties of trisglycine zinc chloride NLO single crystal

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    Bulk single crystals of trisglycine zinc chloride have been grown from aqueous solution by slow cooling technique. Single crystal and powder XRD analyses confirmed orthorhombic crystal structure with non-centrosymmetric space group Pbn2(1). High resolution X-ray diffraction results have established that the quality of the grown crystal is quite good for device fabrication. The crystal was characterized by FTIR and NMR spectral analyses. Optical absorption studies show that the material has very low absorption in the wavelength range 240-2000 nm. The analysis of absorption coefficient in the absorption region reveals a direct band gap of 4.21 eV. The crystal possesses remarkable thermal stability up to 229 degrees C. Photoconductivity studies of the grown crystal revealed the positive photoconducting nature. The grown crystal exhibited considerable hardness anisotropy with Vicker's hardness tester. Dielectric constant and dielectric loss were calculated by varying frequencies at different temperatures
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