5,857 research outputs found

    On Kostant's partial order on hyperbolic elements

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    We study Kostant's partial order on the elements of a semisimple Lie group in relations with the finite dimensional representations. In particular, we prove the converse statement of [3, Theorem 6.1] on hyperbolic elements.Comment: 7 page

    Some Aspects of Tubes Galvanising and Practice at 'Tubes Division' of 'Tata Steel'

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    Hot dip galvanising as it process by which iron & steel can he treated to prevent corrosion. Like other products, hot dip galvanising is most widely used for producing zinc coatings on tubes as this method ensures rapid application of zinc coatings on highly efficient production lines abroad and semi automatic line in India. In India the sec-tor of galvanising tubes is important from the point of view of the tonnage of tubes galvanised and zinc consumed. Although the basic principles of galvanising have remain unchanged for long years, yet continuous research on various aspects of galvanising has enabled this industry to be technically controlled

    Effect of Steel Composition on Zinc Coating and Pot Failure

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    The main topics of this paper are the study of major factors affecting the growth of the zinc coating on steel tubes in a scnti-automatic galvanising plant. By knowing & controlling these factors it is possi- ble to maintain the zinc coating well under control as far as possible. Before discussing he factors affecting zinc coating in details I would like to discuss the structure of zinc coating in short

    DEVELOPMENT AND VALIDATION OF SPECTROPHOTOMETRIC AND ION PAIR CHROMATOGRAPHIC TECHNIQUE FOR ESTIMATION OF VALSARTAN AND HYDROCHLOROTHIAZIDE

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    Two new simple, sensitive, rapid, accurate and reproducible methods (UV-spectrophotometric and ion pair chromatography) have been developed for simultaneous estimation of valsartan (VAL) and hydrochlrothiazide (HCTZ) from their tablet dosage form. The first method involves multiwavelength spectrophotometric method (Method 1) in which interference of HCTZ at 245nm (wavelength for estimation of VAL) was removed by recording absorbance difference at 245nm and 301 nm whereas HCTZ was estimated directly from its absorbance at 316 nm at which VAL shows no absorbance. Linearity of the response was demonstrated by VAL in the concentration range of 5-45 g/ml with a square correlation coefficient (r2) of 0.9998. Linearity of the response was demonstrated by HCTZ in the concentration range of 2-18 g/ml with a square correlation coefficient (r2) of 0.9994. The second method utilizes ion pair chromatography (Method 2) on a HIQ sil ODS column (250 mm* 4.6 mm i.d.) using methanol: 0.0025 M orthophosphoric acid: (70:30 by volume) having pH 4.6: 0.1% hexane sulphonic acid as mobile phase with UV detection at 259nm over concentration range for VAL is 240-0 μg/ml, and for HCTZ is 75-0μg/ml. Losartan potassium was used as the internal standard. The suggested procedures were checked using laboratory prepared mixtures and were applied successfully for the analysis of their tablet dosage form. The results of analysis were statistically analysed. Both the methods were validated as per ICH Q2B guideline

    2D and 3D QSAR studies and antibacterial activity of 4-methyl-3-(6-{[arylmethylene] amino}pyridin-3-YL)-2H-chromen-2-one derivatives

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    4-methyl-3-(6-{[arylmethylene] amino} pyridin-3-yl)-2H-chromen-2-one derivatives containing different functional groups have been synthesized and screened for their antibacterial activity against four different strains of bacteria. 2D and 3D QSAR analysis of synthesized derivatives were performed on Vlife MDS 3.5 software. The data set for QSAR studies encompassed activities of 64 molecules divided into training and test set. The best models were selected on basis of correlation coefficient (r2) and internal and external predictivity (Pred_r2) of the QSAR model. QSAR models reveled that electronic, steric and liphophillic parameters have correlation with antibacterial activity. The 3D interactions and their contributions indicate multi-targeted mode of action of the compounds.Colegio de Farmacéuticos de la Provincia de Buenos Aire

    Synthesis, Characterization and Quantification of Simvastatin Metabolites and Impurities

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    Simvastatin is used in treatment of hypercholesterolemia because it regulates cholesterol synthesis as a result of its β-hydroxy acid acting as an inhibitor of 3-hydroxy-methylglutaryl coenzyme A (HMG-CoA). The present communication deals with synthesis, characterization and development of accurate, precise and sensitive Reverse Phase High Performance Liquid Chromatography (RP-HPLC) method for simultaneous estimation of simvastatin and its synthetic impurities. The impurities methyl ether and β-hydroxy acid of simvastatin were synthesized in the laboratory and characterized by MS, NMR and FT-IR spectroscopy. The separation of simvastatin and its impurities was carried out on an isocratic JASCO RP-HPLC system using KYA TECH HIQ SIL C18 column (150 × 4.6 mm internal diameter, particle size 5 μm) operating at ambient temperature using acetonitrile:water (80:20 v/v) with 0.1% orthophosphoric acid as mobile phase. The method developed for HPLC analysis of three impurities along with simvastatin was validated using ICH Q2B (R1) guidelines and it complied with these guidelines. The results of analysis were found to be in the range of 98.14% to 101.89% for all analytes with acceptable accuracy and precision. The method can be used for detection and quantification of synthetic impurities in bulk or formulations of simvastatin

    Globular clusters as gamma ray sources

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    There are indications now that globular clusters contain a large number of low magnetic field millisecond pulsars. Since millisecond pulsars are expected to emit γ -rays due to curvature radiation, it is likely that globular clusters will themselves be sources of γ -rays bright enough to be detectable by present day instruments. Using the expression derived by Scharlemann, Arons & Fawley (1978) of the energy acquired by the electrons moving along the open magnetic field lines of the pulsars we have calculated the likely luminosity of γ -rays from globular clusters. We discuss our results in the light of the calculations reported in the literature based on some of the other models

    Gamma-ray emission from pulsars

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    We have attempted to devise a scheme by which it may be possible to identify pulsars which are likely to be γ-ray pulsars. We apply this test to a representative population of pulsars and identify the likely candidates for γ emission. We also discuss some individual cases including the Crab and Vela pulsars

    Big brother is watching - using digital disease surveillance tools for near real-time forecasting

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    Abstract for the International Journal of Infectious Diseases 79 (S1) (2019).https://www.ijidonline.com/article/S1201-9712(18)34659-9/abstractPublished versio
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