Investigation of ground state in sodium doped neodymium manganites

With a view to understand the ground state of charge ordered sodium doped neodymium manganites, electrical and magnetic studies were carried out using different measurement protocols and is found to be ferromagnetic. The anomalous low temperature behavior was explained by hindered first-order transition with glass like arrest of kinetics.     

A PASE-based approach towards 12-(1H-1,2,3-triazol-1-yl)-indolo[2,1-a]isoquinolines via the reaction of 3-(isoquinolin-1-yl)-1,2,4-triazines with benzyne

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Indium trichloride: a useful catalyst for ionic Diels–Alder reactions

Indium trichloride (20 mol%) in nitromethane permits ionic Diels–Alder reaction of a variety of 2,3-olefinic acetals to form the corresponding cycloadducts in good yields with good endo selectivities.     

Development and validation of RP‐HPLC‐fluorescence method for quantitative determination of quinidine,a probe substrate for P‐glycoprotein inhibition assay using Caco‐2 cell monolayer

A simple, sensitive and specific reverse‐phase high‐performance liquid chromatographic (RP‐HPLC) method with fluorescence detection was developed for quantitation of quinidine from HBSS buffer. The method was applicable in the bi‐directional transport assay for evaluation of the inhibitory effect of test compounds on P‐glycoprotein‐mediated quinidine transport; quinidine was used as a probe P‐glycoprotein substrate. The calibration curve was linear (correlation coefficient ≥99) in the range 0.30–100.00 nm. The method was validated and is specific and sensitive with limit of quantitation of 300 pm for quinidine. The method was found to be accurate and precise in the working calibration range. Stability studies were carried out at different storage conditions where the analyte was found to be stable. The applicability and reliability of the analytical method was evaluated by successful demonstration of efflux ratio (P_appB → A/P_appA → B) in the Caco‐2 cell monolayer efflux assay. The efflux ratio for quinidine (100 nm) alone was 10.8, which reduced to less than 2 in the presence of the classical P‐gp inhibitors verapamil and ketoconazole (100 μm each). Copyright © 2009 John Wiley & Sons, Ltd.     

Identification and Purification of Metalloprotease from Dry Grass Pea (<Emphasis Type="Italic">Lathyrus sativus</Emphasis> L.) Seeds

Proteolytic enzymes play a central role in the biochemical mechanism of germination. The present study reported the presence of Zn²⁺-dependent endoproteases in the dry seeds of grass pea (Lathyrus sativus L.) with maximum caseinolytic activity observed at pH 8.0. Studies with class-specific inhibitors (specific for cysteine, serine, aspartate, and metalloproteases) on crude extract identified the inhibitory effect of 1,10-phenanthroline. This inhibitory effect was overcome by addition of Zn²⁺, not with Fe, Ca, Cu, Mg, or Co and indicates that the protease is Zn²⁺ dependent. This metalloprotease was further characterized by attempting gelatin-PAGE zymography and observed three distinct zones of proteolytic activity with higher mobility. The protease fraction consisted of three isoforms as evidenced by the appearance of three different bands on gelatin-PAGE zymogram. We also purified these proteases to 110-fold by a three-step procedure comprising crude extract from dry seeds, (NH₄)₂SO₄ fractionation, and casein–alginate affinity chromatography. The molecular mass of isoforms of metalloproteases is 25, 18, and 14 kDa.     

Response Surface Methodology-Based Optimisation of Agarose Gel Electrophoresis for Screening and Electropherotyping of Rotavirus

Management of rotavirus diarrhoea cases and prevention of nosocomial infection require rapid diagnostic method at the patient care level. Diagnostic tests currently available are not routinely used due to economic or sensitivity/specificity constraints. Agarose-based sieving media and running conditions were modulated by using central composite design and response surface methodology for screening and electropherotyping of rotaviruses. The electrophoretic resolution of rotavirus genome was calculated from input parameters characterising the gel matrix structure and running conditions. Resolution of rotavirus genome was calculated by densitometric analysis of the gel. The parameters at critical values were able to resolve 11 segmented rotavirus genome. Better resolution and electropherotypic variation in 11 segmented double-stranded RNA genome of rotavirus was detected at 1.96% (w/v) agarose concentration, 0.073 mol l⁻¹ ionic strength of Tris base–boric acid–ethylenediamine tetraacetic acid buffer (1.4×) and 4.31 h of electrophoresis at 4.6 V cm⁻¹ electric field strength. Modified agarose gel electrophoresis can replace other methods as a simplified alternative for routine detection of rotavirus where it is not in practice.     

Efficient synthesis of 3-acyl-5-hydroxybenzofurans via copper(II) triflate-catalyzed cycloaddition of unactivated 1,4-benzoquinones with 1,3-dicarbonyl compounds

A method to prepare a variety of substituted 3-acyl-5-hydroxybenzofurans efficiently that relies on copper(II) triflate-catalyzed cycloaddition of unactivated 1,4-benzoquinones with 1,3-dicarbonyl compounds is reported. The reaction was shown to be operationally straightforward and proceeds expediently under mild conditions to give the corresponding products in good to excellent yields (up to 95%) and with complete regioselectivity.