188 research outputs found

    Evaluation of Mechanical Properties of SiC Whisker Reinforced In-Situ Composites Prepared by Carbothermal Reduction of Silicate Minerals

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    Al2O3-SiCx, and ZrO_-SiCx, composite powders were prepared by carbothermal reduction of alumino-silicate minerals (kaoline and silimanite) and zircon respectively. The powders were hot pressed at 175011C and 40 MPa pressure in argon atmosphere.Test specimens (4 x 6 x 30 mm3) were made out of hot pressed discs for mechanical properties evaluation. The physical properties i.e. bulk density (B.D.), apparent porosity (A.P.) were measured by Archimedes principle. Young's modulus, fracture toughness and bending strength were measured by resonance frequency response, SENB technique and 4-point bend test respectively. Mechanical properties were found to be better in the case of composites prepared from silimanite and zircon due to optimum whisker content

    Method for Label-Free Quantitative Proteomics for Sorghum bicolor L. Moench

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    Sorghum (Sorghum bicolor L. Moench) is a rapidly emerging high biomass feedstock for bioethanol and lignocellulosic biomass production. The robust varietal germplasm of sorghum and its completed genome sequence provide the necessary genetic and molecular tools to study and engineer the biotic/abiotic stress tolerance. Traditional proteomics approaches for outlining the sorghum proteome have many limitations like, demand for high protein amounts, reproducibility and identification of only few differential proteins. In this study, we report a gel-free, quantitative proteomic method for in-depth coverage of the sorghum proteome. This novel method combining phenol extraction and methanol chloroform precipitation gives high total protein yields for both mature sorghum root and leaf tissues. We demonstrate successful application of this method in comparing proteomes of contrasting cultivars of sorghum, at two different phenological stages. Protein identification and relative quantification analyses were performed by a label-free liquid chromatography tandem mass spectrometry (LC/MS-MS) analyses. Several unique proteins were identified respectively from sorghum tissues, specifically 271 from leaf and 774 from root tissues, with 193 proteins common in both tissues. Using gene ontology analysis, the differential proteins identified were finely corroborated with their leaf/root tissue specific functions. This method of protein extraction and analysis would contribute substantially to generate in-depth differential protein data in sorghum as well as related species. It would also increase the repertoire of methods uniquely suited for gel-free plant proteomics that are increasingly being developed for studying abiotic and biotic stress responses

    Typification of names in the genus Anaphyllum (Araceae)

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    The little-known and small genus Anaphyllum (Araceae), represented by only two species endemic to India, namely A. beddomei and A. wightii, has remained without correctly designated types. Their syntypes are recognized and the names are here typified. The correct bibliographic reference to the protologue of A. wightii is provided for the first time

    Dynamics of Vibrio cholerae in a Typical Tropical Lake and Estuarine System: Potential of Remote Sensing for Risk Mapping

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    Vibrio cholerae, the bacterium responsible for the disease cholera, is a naturally-occurring bacterium, commonly found in many natural tropical water bodies. In the context of the U.N. Sustainable Development Goals (SDG) targets on health (Goal 3), water quality (Goal 6), life under water (Goal 14), and clean water and sanitation (Goal 6), which aim to “ensure availability and sustainable management of water and sanitation for all”, we investigated the environmental reservoirs of V. cholerae in Vembanad Lake, the largest lake in Kerala (India), where cholera is endemic. The response of environmental reservoirs of V. cholerae to variability in essential climate variables may play a pivotal role in determining the quality of natural water resources, and whether they might be safe for human consumption or not. The hydrodynamics of Vembanad Lake, and the man-made barrier that divides the lake, resulted in spatial and temporal variability in salinity (1–32 psu) and temperature (23 to 36 °C). The higher ends of this salinity and temperature ranges fall outside the preferred growth conditions for V. cholerae reported in the literature. The bacteria were associated with filtered water as well as with phyto- and zooplankton in the lake. Their association with benthic organisms and sediments was poor to nil. The prevalence of high laminarinase and chitinase enzyme expression (more than 50 µgmL−1 min−1) among V. cholerae could underlie their high association with phyto- and zooplankton. Furthermore, the diversity in the phytoplankton community in the lake, with dominance of genera such as Skeletonema sp., Microcystis sp., Aulacoseira sp., and Anabaena sp., which changed with location and season, and associated changes in the zooplankton community, could also have affected the dynamics of the bacteria in the lake. The probability of presence or absence of V. cholerae could be expressed as a function of chlorophyll concentration in the water, which suggests that risk maps for the entire lake can be generated using satellite-derived chlorophyll data. In situ observations and satellite-based extrapolations suggest that the risks from environmental V. cholerae in the lake can be quite high (with probability in the range of 0.5 to 1) everywhere in the lake, but higher values are encountered more frequently in the southern part of the lake. Remote sensing has an important role to play in meeting SDG goals related to health, water quality and life under water, as demonstrated in this example related to cholera

    Identification of Nedd4 E3 Ubiquitin Ligase as a Binding Partner and Regulator of MAK-V Protein Kinase

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    MAK-V/Hunk is a scantily characterized AMPK-like protein kinase. Recent findings identified MAK-V as a pro-survival and anti-apoptotic protein and revealed its role in embryonic development as well as in tumorigenesis and metastasis. However molecular mechanisms of MAK-V action and regulation of its activity remain largely unknown. We identified Nedd4 as an interaction partner for MAK-V protein kinase. However, this HECT-type E3 ubiquitin ligase is not involved in the control of MAK-V degradation by the ubiquitin-proteasome system that regulates MAK-V abundance in cells. However, Nedd4 in an ubiquitin ligase-independent manner rescued developmental defects in Xenopus embryos induced by MAK-V overexpression, suggesting physiological relevance of interaction between MAK-V and Nedd4. This identifies Nedd4 as the first known regulator of MAK-V function

    Impact of alternative solid state forms and specific surface area of high-dose, hydrophilic active pharmaceutical ingredients on tabletability

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    YesIn order to investigate the effect of using different solid state forms and specific surface area (TBET) of active pharmaceutical ingredients on tabletability and dissolution performance, the mono- and dihydrated crystalline forms of chlorothiazide sodium and chlorothiazide potassium (CTZK) salts were compared to alternative anhydrous and amorphous forms, as well as to amorphous microparticles of chlorothiazide sodium and potassium which were produced by spray drying and had a large specific surface area. The tablet hardness and tensile strength, porosity, and specific surface area of single-component, convex tablets prepared at different compression pressures were characterized. Results confirmed the complexity of the compressibility mechanisms. In general it may be concluded that factors such as solid-state form (crystalline vs amorphous), type of hydration (presence of interstitial molecules of water, dehydrates), or specific surface area of the material have a direct impact on the tabletability of the powder. It was observed that, for powders of the same solid state form, those with a larger specific surface area compacted well, and better than powders of a lower surface area, even at relatively low compression pressures. Compacts prepared at lower compression pressures from high surface area porous microparticles presented the shortest times to dissolve, when compared with compacts made of equivalent materials, which had to be compressed at higher compression pressures in order to obtain satisfactory compacts. Therefore, materials composed of nanoparticulate microparticles (NPMPs) may be considered as suitable for direct compaction and possibly for inclusion in tablet formulations as bulking agents, APIs, carriers, or binders due to their good compactibility performanceSolid State Pharmaceutical Cluster (SSPC), supported by Science Foundation Ireland under Grant No. 07/SRC/B1158

    Combinations of Plant Water-Stress and Neonicotinoids Can Lead to Secondary Outbreaks of Banks Grass Mite (Oligonychus Pratensis Banks)

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    Spider mites, a cosmopolitan pest of agricultural and landscape plants, thrive under hot and dry conditions, which could become more frequent and extreme due to climate change. Recent work has shown that neonicotinoids, a widely used class of systemic insecticides that have come under scrutiny for non-target effects, can elevate spider mite populations. Both water-stress and neonicotinoids independently alter plant resistance against herbivores. Yet, the interaction between these two factors on spider mites is unclear, particularly for Banks grass mite (Oligonychus pratensis; BGM). We conducted a field study to examine the effects of water-stress (optimal irrigation = 100% estimated evapotranspiration (ET) replacement, water stress = 25% of the water provided to optimally irrigated plants) and neonicotinoid seed treatments (control, clothianidin, thiamethoxam) on resident mite populations in corn (Zea mays, hybrid KSC7112). Our field study was followed by a manipulative field cage study and a parallel greenhouse study, where we tested the effects of water-stress and neonicotinoids on BGM and plant responses. We found that water-stress and clothianidin consistently increased BGM densities, while thiamethoxam-treated plants only had this effect when plants were mature. Water-stress and BGM herbivory had a greater effect on plant defenses than neonicotinoids alone, and the combination of BGM herbivory with the two abiotic factors increased the concentration of total soluble proteins. These results suggest that spider mite outbreaks by combinations of changes in plant defenses and protein concentration are triggered by water-stress and neonicotinoids, but the severity of the infestations varies depending on the insecticide active ingredient

    SIK1/SOS2 networks: decoding sodium signals via calcium-responsive protein kinase pathways

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    Changes in cellular ion levels can modulate distinct signaling networks aimed at correcting major disruptions in ion balances that might otherwise threaten cell growth and development. Salt-inducible kinase 1 (SIK1) and salt overly sensitive 2 (SOS2) are key protein kinases within such networks in mammalian and plant cells, respectively. In animals, SIK1 expression and activity are regulated in response to the salt content of the diet, and in plants SOS2 activity is controlled by the salinity of the soil. The specific ionic stress (elevated intracellular sodium) is followed by changes in intracellular calcium; the calcium signals are sensed by calcium-binding proteins and lead to activation of SIK1 or SOS2. These kinases target major plasma membrane transporters such as the Na+,K+-ATPase in mammalian cells, and Na+/H+ exchangers in the plasma membrane and membranes of intracellular vacuoles of plant cells. Activation of these networks prevents abnormal increases in intracellular sodium concentration
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