n vitro study of antiamoebic effect of methanol extract of mature seeds of Carica papaya on trophozoites of Entamoeba histolytica

Antiamoebic activity of methanol extract of mature seeds of Carica papaya was tested in vitro on axenic culture of Entamoeba histolytica using metronidazole as a reference amoebicidal agent. The MIC of seed extract was > 62.5 µg/mL as compared to < 0.8 µg/mL for metronidazole. The present study suggests that the mature seeds of C. papaya have antiamoebic effect but less pronounced than metronidazole

A simple route to enantiopure bis-lactones: synthesis of both enantiomers of epi-nor-canadensolide, nor-canadensolide, and canadensolide

A simple strategy has been developed for the synthesis of both enantiomers of nor-canadensolide, epi-nor-canadensolide, and an intermediate to canadensolide. An orthoester Claisen rearrangement of an appropriately constructed allyl alcohol derivative prepared from R-(+)-2,3-di-O-cyclohexylidine glyceraldehyde followed by epoxidation of the resulting unsaturated esters produced hydroxy-lactones, which on oxidation gave keto-lactones. Stereoselective reduction of the keto-carbonyl using either a chelation controlled or a non-chelation controlled process led to the natural or the epi-series, respectively. The interplay of the electronic effect between the polar groups and the steric effect of the β -substituent during reduction of the keto-lactones turned out to be the key factors in deciding the stereochemical outcome. Regeneration of the aldehyde functionality latent in the ketal moiety of the hydroxy-lactones provided the lactols, which on oxidation gave the bis-lactones

Data-driven evidential belief function (EBF) model in exploring landslide susceptibility zones for the Darjeeling Himalaya, India

In the present study, data-driven evidential belief function model (belief function) was employed to generate landslides susceptibility index map of Darjeeling Himalaya considering 15 landslide causative factors, which grouped into six categories, i.e. geomorphological factors (elevation, aspect, slope, curvature), lithological factors (geology, soil, lineament density, distance to lineament), hydrologic factors (drainage density, distance to drainage, stream power index, topographic wetted index), triggering factor (rainfall), protective factor (normalized differential vegetation index) and anthropogenic factor (land use and land cover). Total 2079 landslide locations were mapped and randomly divided it into training datasets (70% landslide locations) and validation datasets (30% landslide locations). The resultant susceptibility map was divided into five different susceptibility zones i.e. very low, low, moderate, high and very high which covered 5.60%, 25.65%, 34.47%, 24.67% and 9.61% area respectively of the Darjeeling Himalaya. Receiver operating characteristics curve suggested that 80.20% prediction accuracy of the prepared map whereas frequency ratio plot indicated towards the ideal landslides susceptibility index map

Anodic deposition of porous RuO2 on stainless steel for supercapacitor studies at high current densities

Ruthenium dioxide is deposited on stainless steel (SS) substrate by galvanostatic oxidation of Ru3+. At high current densities employed for this purpose, there is oxidation of water to oxygen, which occurs in parallel with Ru3+ oxidation. The oxygen evolution consumes a major portion of the charge. The oxygen evolution generates a high porosity to RuO2 films, which is evident from scanning electron microscopy studies. RuO2 is identified by X-ray photoelectron spectroscopy. Cyclic voltammetry and galvanostatic charge–discharge cycling studies indicate that RuO2/SS electrodes possess good capacitance properties. Specific capacitance of 276 F g−1 is obtained at current densities as high as 20 mA cm−2 (13.33 A g−1). Porous nature of RuO2 facilitates passing of high currents during charge–discharge cycling. RuO2/SS electrodes are thus useful for high power supercapacitor applications

A chiral mononuclear oxovanadium(V) ethyleneglycolate complex

171-173The title complex [VO(sv)(Heg)],incorporating the doubly deprotonated tridentate salicylaldimine of -valine (sv2-) and half-deprotonated bidentate ethyleneglycol (Heg-) has been synthesised and structurally characterised. Its chiral configuration is CS both in the solid state and solution. The complex represents the first structural characterization of mononuclear binding of oxovanadium(V) by ethyleneglycol

Multivariate Analysis in Selective Nitroacetophenone Conversion by Hydrogen Sulfide under Phase Transfer Catalysis

Response surface methodology (RSM) was employed to model and optimize an improved Zinin reduction of a nitroarene, <i>p</i>-nitroacetophenone (<i>p</i>-NAP), by hydrogen sulfide (H₂S) under biliquid phase transfer catalysis. A novel Zinin reagent, H₂S laden aqueous <i>N</i>-methyldiethanolamine (MDEA) solution, was prepared and used for this purpose. A quadratic regression model was tested with a multivariate experimental design based on the relationship between <i>p</i>-NAP conversion (response) and four independent variablestemperature, catalyst concentration, <i>p</i>-NAP–sulfide mole ratio, and MDEA concentration. The optimum values of the independent variables were found as temperature 339.45 K, catalyst concentration of 0.082 kmol/m³, <i>p</i>-NAP/sulfide mole ratio of 0.452, MDEA concentration of 2.20 kmol/m³, and maximum <i>p</i>-NAP conversion of 96.31% has been attained. The analysis of variance (ANOVA) has been used to evaluate the goodness of the fit of the model, and the desirability function has been used to find the value of the optimized parameters to maximize the <i>p</i>-NAP conversion

Synthesis and structure of carboxyl-bonded oxovanadium(V) complexes incorporating α-amino acid salicylaldiminates and quinolin-8-olate

The complexes [VO(L¹)(hquin)] and [VO(L²)(hquin)] incorporating N-salicylidene-glycinate and -L-phenylalaninate respectively have been synthesised in excellent yields from [V^IVO(L)(H₂O)] and quinolin-8-ol (Hhquin) in air which acts as the oxidant. The crystal structure of [VO(L²)(hquin)] revealed tridentate ONO and bidentate ON binding by [L²]^2– and hquin^– respectively. The V–O (carboxylate) bond length is longer than V–O (phenolate) by ≈0.1 Å. The CD spectrum of [VO(L²)(hquin)] in the visible region revealed the composite nature of the phenolato→vanadium charge-transfer band. The absolute configuration of [VO(L²)(hquin)] is CS both in the crystalline state and in solution. In CDCl₃ solution the ¹H NMR spectrum of the complex shows that the amino acid side chain has the same conformation as that in the crystal lattice. The complexes display the quasi-reversible one-electron couple [VO(L)(hquin)]–[VO(L)(hquin)]– near 0.0 V vs. saturated calomel electrode. Electrogenerated solutions of [VO(L)(hquin)]^– are EPR-active corresponding to a d_xy¹ configuration