ANTIMICROBIAL ACTIVITY OF AQUEOUS AND ETHANOLIC LEAF EXTRACTS OF ANACARDIUM OCCIDENTALE

Objective: The objective of this study was to evaluate the antimicrobial activity of leaves of Anacardium occidentale (A. occidentale) against microorganisms including multidrug-resistant (MDR) bacteria. Methods: Agar well diffusion method was employed to demonstrate the antimicrobial activity of leaves A. occidentale. Ethanol and aqueous extracts of the leaves were used against microorganisms, which included American type culture collection strains of Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Enterococcus faecalis, and Pseudomonas aeruginosa and the clinical isolates of Streptococcus pneumoniae, Candida albicans, MDR Escherichia coli, and MDR Klebsiella pneumoniae. Results: The ethanolic extract of leaves of A. occidentale showed significant antimicrobial activity. Aqueous extract had mild antifungal activity. Conclusion: Ethanolic extract of leaves of A. occidentale could be a good source for the antibacterials to combat MDR bacterial infections. Further studies are necessary for these potent plant extracts to evaluate the in vivo efficacy and toxicity

Nitrides as ammonia synthesis catalysts and as potential nitrogen transfer reagents

In this article, an overview of the application of selected metal nitrides as ammonia synthesis catalysts is presented. The potential development of some systems into nitrogen transfer reagents is also described

Temperature Dependent Photoluminescence Studies in Hg0.2Cd0.8Te Nanorods Synthesized by Solvothermal Method

Hg0.2Cd0.8Te nanorods were synthesized via solvothermal route using an air-stable Na2Te-O-3. The structural and morphological studies were done by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The diameters of the nanorods were found to be 20-50 nm. The growth of the nanorods were facilitated due to the use of CTAB as surfactant. The temperature dependent photoluminescence (PL) studies between 10-300 K show three prominent PL bands in 0.5-0.7 eV and are attributed to defect centers. The features like temperature independent peak energy and quite sensitive PL intensity which shows a thermal quenching behavior indicate that the defects are related to the compositional disorder

Hydrothermal synthesis of CdTe QDs: Their luminescence quenching in the presence of bio-molecules and observation of bistable memory effect in CdTe QD/PEDOT:PSS heterostructure

We report one-pot hydrothermal synthesis of nearly mono-disperse 3-mercaptopropionic acid capped water-soluble cadmium telluride (CdTe) quantum dots (QDs) using an air stable Te source. The optical and electrical characteristics were also studied here. It was shown that the hydrothermal synthesis could be tuned to synthesize nano structures of uniform size close to nanometers. The emissions of the CdTe QDs thus synthesized were in the range of 500-700 nm by varying the duration of synthesis. The full width at half maximum (FWHM) of the emission peaks is relatively narrow (40-90 nm), which indicates a nearly uniform distribution of QD size. The structural and optical properties of the QDs were characterized by transmission electron microscopy (TEM), photoluminescence (PL) and Ultraviolet-visible (UV-Vis) spectroscopy. The photoluminescence quenching of CdTe QDs in the presence of L-cysteine and DNA confirms its biocompatibility and its utility for biosensing applications. The room temperature current-voltage characteristics of QD film on ITO coated glass substrate show an electrically induced switching between states with high and low conductivities. The phenomenon is explained on the basis of charge confinement in quantum dots. (C) 2011 Elsevier B.V. All rights reserved

A seismotectonic study of the 21 May 2014 Bay of Bengal intraplate earthquake: evidence of onshore-offshore tectonic linkage and fracture zone reactivation in the northern Bay of Bengal

The earthquake of 21 May 2014 (Mw 6.0) in the northern Bay of Bengal (BOB) highlights the importance of studies on intraplate earthquakes in the oceanic regime for understanding the stress state of the oceanic lithosphere. The epicenter of the earthquake is located at a water depth of 2.5 km where the sediment thickness is nearly 12 km, and it occurs at a depth of similar to 50 km within the upper mantle. Its location on the seismotectonic map of the region shows that the epicenter is far from the seismically active zone of the Burmese Arc in the east and low-to-moderately active seismic region of the east coast of India in the west. The fault plane solution of this earthquake indicates that it was a strike-slip event with a right-lateral sense of motion on a NW-oriented nodal plane, and it occurred on one of the NW-SE-trending fracture zones previously mapped in the BOB. Based on a compilation of long-term (1900-2011) intraplate earthquakes along with available focal mechanisms in the BOB and the adjoining east coast of India, we conclude the following: (1) the Precambrian structural trends, basin-scale faults and minor lineaments on the east coast of India are favorably reactivated in their offshore extensions up to the shelf-slope areas of the margin; (2) earthquake occurrences in the BOB region can be correlated with the fracture zone trends in the central BOB and along the Ninetyeast ridge or at the intersections of fracture zones with the subsurface trace of the 85A degrees E ridge. The 21 May 2014 earthquake is the result of reactivation of such a NW-SE-trending fracture zone lying in the lithosphere of > 100 Ma in age. Further evaluation of this event in light of the global occurrence of oceanic intraplate earthquakes in the older lithosphere (> 80 Ma) suggests that such reactivation is possible in the high ambient stress state

Estimation of trap concentration in linearly graded junctions using DLTS

A method is proposed to estimate the deep trap concentration in a linearly graded junction from DLTS. The deep impurity is assumed to be uniformly distributed and much smaller in concentration than the shallow impurities. The effects of the edge-region and the zero bias depletion region are important and included in this model. Es wird eine Methode vorgeschlagen, aus DLTS die Konzentration tiefer Haftstellen in einem linearen Ubergang zu berechnen. Es wird angenommen, da$\beta$ die tiefe Storstelle gleichformig verteilt ist und in vie1 geringerer Konzentration als die flachen Storstellen vorliegt. Die Einfliisse des Kantenbereichs und des Verarmungsbereichs ohne Vorspannung sind wesentlich und werden in diesem Modell einbegriffen

Pt/CdTe/Pt asymmetric nano-Schottky diodes from colloidal quantum dots

We have fabricated nano-Schottky diodes of CdTe QDs with platinum metal electrodes in metal-semiconductor-metal planar configuration by drop-casting. The observed high value of ideality factor (13.3) of the diode was possibly due to the presence of defects in colloidal QDs. We observed asymmetry and non-linear nature of I-V characteristics between forward and reverse directions, which has been explained in terms of size distributions of quantum dots due to coffee ring effect. Copyright 2011 Author(s). This article is distributed under a Creative Commons Attribution 3.0 Unported License. doi:10.1063/1.3669408