596 research outputs found

    A facile reductive cleavage of allylic and benzylic esters with low valent titanium reagents

    Get PDF
    The reductive cleavage of allylic and benaylic esters 1a-g̲ with titanium(II) reagent derived from Mg/Hg-TiCl yielded the corresponding acids 3a-g̲ and dimeric hydro 4 carbons 2a-g̲ under mild reaction conditions

    An efficient and highly selective method for deoximation of ketoximes

    Get PDF
    A combination of pyridinium dichromate/tert-butyl hydroperoxide (1:1) has been found to be an excellent reagent for the highly selective regeneration of ketones from ketoximes

    Detection and diagnosis of dilated cardiomyopathy and hypertrophic cardiomyopathy using image processing techniques

    Get PDF
    AbstractMajor heart diseases like heart muscle damage and valvular problems are diagnosed using echocardiogram. Since the echocardiogram is an image or sequence of images with less information the cardiologist spends more time to predict or to make decision. Automating the detection and diagnosis of dilated cardiomyopathy (DCM) and hypertrophic cardiomyopathy (HCM) is a key enabling technology in computer aided diagnosis systems. In this paper, a system is proposed to automatically detect and diagnose dilated cardiomyopathy (DCM) and hypertrophic cardiomyopathy (HCM). This system performs denoising, enhancement, before left ventricular segmentation is carried out in the individual frames. Using the segmented left ventricle, the LV parameters like volume and ejection fraction (EF) are calculated and also the end-diastolic LV is extracted. The PCA and DCT features are obtained from the extracted end-diastolic LV and the classifiers BPNN, SVM and combined K-NN are used to classify the normal hearts, hearts affected with DCM and hearts affected with HCM. The PCA feature with BPNN classifier gives a highest overall accuracy of 92.04% in classifying normal and abnormal hearts. Experiments over 60 echocardiogram videos expose that the proposed system can be effectively utilized to detect and diagnose DCM and HCM

    Padina boergessenii ameliorates carbon tetrachloride induced nephrotoxicity in Wistar rats

    Get PDF
    AbstractThis research investigates the ameliorative effect of brown alga Padina boergessenii against CCl4-induced nephrotoxicity in rats. Twenty-four Wistar albino rats were divided into four groups as follows: control group (saline), CCl4 group, CCl4+P. boergessenii extract group and P. boergessenii extract alone group. At the end of the experimental period, the animals are sacrificed and tissue samples (kidney) were collected. CCl4 at a dose of 2mL/kg, administered subcutaneously, produced significantly decreased activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT). Histopathological examinations showed massive centrilobular necrosis and fat accumulation in CCl4-induced animals. In the protective test, especially in animals pretreated with P. boergessenii (150mg/kg) extract, there was a significant increase in antioxidant enzyme levels although there was no sign of abnormality in the kidney of rats pretreated with extract as evidenced by histopathological sections against CCl4-induced decrease of lipid peroxidation (TBARS). The ameliorative effect may be due to the presence of various bioactive compounds in alga. These results suggest that an extract of P. boergessenii is able to significantly alleviate the nephrotoxicity induced by CCl4 in Wistar rats

    Assessment of seasonal groundwater quality using CHIDAM software in Virudhunagar district of Tamil Nadu.

    Get PDF
    Hard rock aquifer is the most predominant in the southern peninsula exclusively in Tamil Nadu, India. Virudhunagar district is situated in the South west part of Tamil Nadu, mostly of hard rock topography. Groundwater plays a major role in this area contributing to domestic, irrigation and industrial practices. Running down of groundwater by extreme consumption and less recharge in the study area has reduced the level of groundwater. On the other hand, intensive domestic, agriculture and industrial practices impacts the quality of quality of groundwater as well. Hydro geochemistry plays an important role in evaluation of suitability of groundwater for its usage in several purposes. A total of 72 samples from North East Monsoon (NEM) and Post Monsoon (POM) has been analyzed hydrochemically. The irrigation quality parameters such as sodium adsorption ratio (SAR), %Na, Residual Sodium Carbonate (RSC), Kelley’s index and Magnesium hazard were calculated using CHIDAM software 2020 in conjunction with USSL and Doneen diagrams. During NEM, EC and TDS ranges from 273 to 5869 mg/L and 194 to 4159 mg/L and during POM is from 235 to 6850 mg/L and 233.8 to 6916 mg/L. The hydrogeochemical facies represents that Ca-HCO3 and mixed Ca-Mg-Cl facies are predominant during NEM and Na-Cl and mixed Ca-Mg-Cl are predominant during POM. The higher concentration of TDS and EC in the samples reflects the unsuitability of groundwater in both seasons

    Assessment of sources and distribution metals in groundwater of Pondicherry region, India

    Get PDF
    The proposed study investigates the seasonal variation in the concentration and the source of the heavy metals like Mn, Cu, Pb, Zn and Fe in the groundwater samples of Pondicherry region. The study results reveal that, the heavy metal concentration is high during South West Monsoon season (SWM) compared to that of North East Monsoon season (NEM). The pH was near neutral and metal load representing most of the samples were low during NEM. Statistical analysis shows that the 63.7 % of the total variance is observed during NEM and 68.9% during SWM. Geographic information system (GIS) tool was considered for the study to understand the environmental pollution status of the groundwater systems of the study area and to identify the groundwater quality parameters. The multivariate statistical analysis explains that the source of trace metal in the groundwater is derived from natural origin except copper and lead as these contaminants were derived from anthropogenic activities. Based on the output of WATEQ4F, several species of heavy metals exist, in which the dominant species are Mn, CuCl2, PbCO3, Fe and Zn

    Kernels for Grassmann flops

    Get PDF
    We develop a generalization of the QQ-construction of the first author, Diemer, and the third author for Grassmann flips. This generalization provides a canonical idempotent kernel on the derived category of the associated global quotient stack. The idempotent kernel, after restriction, induces a semi-orthogonal decomposition which compares the flipped varieties. Furthermore its image, after restriction to the geometric invariant theory semistable locus, "opens" a canonical "window" in the derived category of the quotient stack. We check this window coincides with the set of representations used by Kapranov to form a full exceptional collection on Grassmannians

    Potential functions for hydrogen bond interactions. IV. Minimum energy conformation of the α-helical structure of poly-L-alanine

    Get PDF
    Making use of the empirical potential functions for peptide NH .. O bonds, developed in this laboratory, the relative stabilities of the right and left-handed α-helical structures of poly-L-alanine have been investigated, by calculating their conformational energies (V). The value of Vmin of the right-handed helix (αP) is about — 10.4 kcal/mole, and that of the left-handed helix (αM) is about — 9.6 kcal/mole, showing that the former is lower in energy by 0.8 kcal/mole. The helical parameters of the stable conformation of αP are n ∼ 3.6 and h ∼ 1.5 Å. The hydrogen bond of length 2.85 Å and nonlinearity of about 10° adds about 4.0 kcal/ mole to the stabilising energy of the helix in the minimum enregy region. The energy minimum is not sharply defined, but occurs over a long valley, suggesting that a distribution of conformations (ϕ, ψ) of nearly the same energy may occur for the individual residues in a helix. The experimental data of α-helical fibres of poly-L-alanine are in good agreement with the theoretical results for αP. In the case of proteins, the mean values of (ϕ, ψ) for different helices are distributed, but they invariably occur within the contour for V = Vmin + 2 kcal/mole for αP

    Potential functions for hydrogen bond interactions. III. Empirical potential function for the peptide N-H...O=C hydrogen bond

    Get PDF
    A careful comparison of the distribution in the (R, θ )-plane of all NH ... O hydrogen bonds with that for bonds between neutral NH and neutral C=O groups indicated that the latter has a larger mean R and a wider range of θand that the distribution was also broader than for the average case. Therefore, the potential function developed earlier for an average NH ... O hydrogen bond was modified to suit the peptide case. A three-parameter expression of the form Vℏδ = Vmin + p1 Δ2 + q1 ep3 Δ , θ2 with ∃ = R - Rmin, was found to be satisfactory. By comparing the theoretically expected distribution in R and θ with observed data (although limited), the best values were found to be p1 = 25,p3 = - 2 and q1 = 1 x 10-3, with Rmin = 2.95 Å and Vmin = - 4.5 kcal/mole. The procedure for obtaining a smooth transition from Vhb to the non-bonded potential Vnb for large R and θ is described, along with a flow chart useful for programming the formulae. Calculated values of ΔH, the enthalpy of formation of the hydrogen bond, using this function are in reasonable agreement with observation. When the atoms involved in the hydrogen bond occur in a five-membered ring as in the sequence a different formula for the potential function is needed, which is of the form Vℏδ = Vmin +p 1∃2 +q 1 x 2 where x = θ - 50° for θ ≥ 50°, with p1 = 15, q1 = 0.002, Rmin = 2.8 Å and Vmin = - 2.5 kcal/mole
    corecore