Green Synthesis of Silver Nanoparticles using Litsea glutinosa L. Leaves and Stem Extracts and their Antibacterial Efficacy

The present study explores the green approach for the preparation of silver nanoparticles (AgNPs) through the reduction of silver nitrate by the cell-free stem and leaf aqueous extracts of Litsea glutinosa (L.glutinosa) and its potential antibacterial activity. The analytical instruments include scanning electron microscopy, Fourier transforms infrared spectroscopy, UV-visible spectroscopy, and X-ray diffraction spectroscopy confirmed the synthesis of smaller, uniformly spherical AgNPs (10-40 nm). The average crystalline size of prepared AgNPs produced by L. glutinosa leaf extract was found to be 19 mm. From UV-visible spectral analysis, the maximum absorbance peak appeared at 444 nm for leaf extract AgNPs different from stem extract AgNPs (422 nm), which are found to be specific for AgNPs. The L.glutinosa stem extract-assisted AgNPs have shown significant antibacterial activity against Bacillus subtilis (Gram-positive) and Escherichia coli (Gram-negative) in comparison to Gentamycin. Hence, the AgNPs obtained by green synthesis can be therapeutically explored against bacterial infections

Emerging Themes and Future Directions of Multi-Sector Nexus Research and Implementation

Water, energy, and food are all essential components of human societies. Collectively, their respective resource systems are interconnected in what is called the “nexus”. There is growing consensus that a holistic understanding of the interdependencies and trade-offs between these sectors and other related systems is critical to solving many of the global challenges they present. While nexus research has grown exponentially since 2011, there is no unified, overarching approach, and the implementation of concepts remains hampered by the lack of clear case studies. Here, we present the results of a collaborative thought exercise involving 75 scientists and summarize them into 10 key recommendations covering: the most critical nexus issues of today, emerging themes, and where future efforts should be directed. We conclude that a nexus community of practice to promote open communication among researchers, to maintain and share standardized datasets, and to develop applied case studies will facilitate transparent comparisons of models and encourage the adoption of nexus approaches in practice

Emerging Themes and Future Directions of Multi-Sector Nexus Research and Implementation

Water, energy, and food are all essential components of human societies. Collectively, their respective resource systems are interconnected in what is called the “nexus”. There is growing consensus that a holistic understanding of the interdependencies and trade-offs between these sectors and other related systems is critical to solving many of the global challenges they present. While nexus research has grown exponentially since 2011, there is no unified, overarching approach, and the implementation of concepts remains hampered by the lack of clear case studies. Here, we present the results of a collaborative thought exercise involving 75 scientists and summarize them into 10 key recommendations covering: the most critical nexus issues of today, emerging themes, and where future efforts should be directed. We conclude that a nexus community of practice to promote open communication among researchers, to maintain and share standardized datasets, and to develop applied case studies will facilitate transparent comparisons of models and encourage the adoption of nexus approaches in practice

Studies on biologically relevant ternary metal complexes: Part V-Stability of ternary Co(II), Ni(II), Zn(II), and Cd(III) complexes containing bis(imidazol-2-yl)methane as primary ligand and amino acids as secondary ligands

996-1001The formation constants of ternary complexes of the type ML2A, where M = Co(II), Ni(II), Zn(II) or Cd(II), L= bis(imidazol-2-yl)methane (BIM) and A= glycine, alanine, valine, norvaline, leucine, norleucine, phenylalanine, tryptophan, serine, threonine, methionine, histidine, aspartic acid, pyrocatechol or ethylenediamine have been determined potentiometrically at 35°C and μ = 0.2 M (KNO3). The stabilities of various ternary metal complexes have been quantitatively compared with those of the corresponding binary complexes (MA) in terms of the parameter log K1 (where log K1 = log K-log K). The relative stabilities of the ternary metal complexes containing amino acids with aromatic side chain have been quantitatively compared with those of the corresponding ternary complexes containing alanine(ALA) in terms of the parameter log K2 which is the constant for the equilibrium: M(A) + ML2(ALA) ML2(A) + M(ALA). The enhanced stability of ternary metal complexes containing phenylalanine or tryptophan is attributed to intramolecular metal ion mediated stacking interactions between the aromatic moieties of amino acids and the imidazole rings of bis(imidazol-2-yl)methane. Ternary complexes containing the tridentate amino acids, aspartic acid and histidine are destabilized to a greater extent due to a combination of statistical effect and the decrease in the denticity of these ligands from tridentate in binary to bidentate in ternary complexes. The relative ability of donor atoms in ligand(A) tobind to [M - (BIM)2]2+ complex is found to increase in the order N - N -. The factors contributing to the stability of the various ternary complexes have been discussed

An efficient heterogenised palladium catalytic system for the reductive carbonylation of nitrobenzene to methyl N-phenylcarbamate

A highly active and selective heterogenised homogeneous catalyst, montmorillonitebipyridinepalladium (II) acetate complex for the reductive carbonylation of nitrobenzene to methyl N-phenylcarbamate is reported. With the additional advantages such as ease of filterability and reusability for several cycles with consistent activity and selectivity, the heterogenised system will become practical alternative to the other systems described earlier

Conversion of primary amines to N,N'-disubstituted ureas using montmorillonitebipyridinepalladium(II)-acetate and di-tert butyl peroxide

A simple and convenient methodology for the synthesis of N,N'-disubstituted ureas from primary amines by a heterogenized catalyst montmorillonitebipyridinepalladium (II)acetate for the first time at room temperature and atmospheric pressure is described

Analytical method development and validation for the simultaneous estimation of Levamisole and Mebendazole in bulk & tablet formulation by RP-HPLC method

A fast, robust and accurate RP-HPLC method was developed and validated for simultaneous determination of Levamisole and Mebendazole in tablets. The mobile phase was mixture of aqueous phosphate buffer with pH 5.2: Methanol: Acetonitrile (30:20:50 v/v/v), effluent flow rate monitored at 1.0 ml/min. the stationary phase was C18 column, zodiac 5µ (4.6×250mm). The solutions of standard and the sample were prepared in methanol. The retention times was found to be 2.427min and 4.110min for Levamisole and Mebendazole respectively at 235nm. Calibration graphs constructed at their wavelengths of determination were linear in the concentration range of 150-210µg/ml. The percentage assay for Levamisole and Mebendazole were found to be 99.94 % and 99.35%respectively. The LOD and LOQ were found to be0.0034µgm/ml and 0.00104µgm/ml for Levamisole, 90-210µgm/ml and 60-140µgm/ml for Mebendazole. The method was validated and it was found to be accurate, precise, linear and reproducible