Microbial Extraction of Cobalt and Nickel from Lateritic Chromite Overburden using Aspergillus wentii

ABSTRACT Low-grade nickeliferous lateritic ore from Sukinda region of Orissa, India, was subjected to biohydrometallurgical treatment for the extraction of nickel and cobalt. The mineralogical studies reveal that nickel is entrapped in goethite matrix while cobalt is associated with the manganese phase. Aspergillus wentii NCIM 667, a citric acid producing fungal strain, was used for direct (one step and two step) and indirect (using culture filtrate) leaching of the metals under different conditions. The effect of varying pulp density (2%, 5%, 8%) and culture medium composition (viz. molasses and sucrose media) was investigated and the leaching conditions optimized. It was found that a maximum of 49.29% Ni and 35.18% Co could be recovered from the heat-treated lateritic chromite overburden by the culture filtrate bioleaching at 80°C with 2% pulp density

Molecular Imprinting of Luminescent Vesicles

Applying molecular imprinting techniques to the surface of functionalized unilammelar fluid vesicles allows the preparation of specific and high-affinity luminescent chemosensors. We have photopolymerized diacetylene containing vesicles in the presence of small peptides as templates yielding imprinted polydiacetylene (PDA) patches in the membrane. They serve as multivalent receptor sites with significantly increased rebinding affinity for the template. All binding sites are surface exposed and accessible for analyte binding. The presence of analytes is signaled with high sensitivity by emission intensity changes of amphiphilic carboxyfluorescein, which is coembedded into the fluid DOPC membrane. The merger of PDA imprinting with dynamic functionalized vesicles overcomes some of the current limitations of molecular imprinting in chemosensor design and may be applied to many different target analyte

PROCESS PARAMETER OPTIMIZATION IN LATHE TURNING OPERATION TO IMPROVE THE SURFACE ROUGHNESS AND REDUCE THE CUTTING FORCE USING TAGUCHI METHOD

This paper represents an experimental study of Process Parameter Optimization to Improve the Surface Roughness generated and Reduction of the Cutting Force used in Lathe Turning Operation on a mild steel job and optimization of machine parameters by Taguchi Method. The Surface Roughness Parameter is the Response Surface Methodology. For developing mathematical model for predicting surface roughness parameter and cutting forces, the threelevel central composite design is employed.Taguchi method is a statistical approach in optimizing the process parameters used in quality control process to improve the quality of the manufactured component. In the following analysis three parameters namely speed, feed and depth of cut were considered. Experiment was conducted considering a suitable orthogonal array. Cutting force and surface roughness were measured and Signal to Noise ratio was calculated. Analyzing the graph provided us with the optimumvalue

Supramolecular gels 'in action'

In recent years, self-assembly has emerged as a powerful tool for the construction of functional nanostructures. Myriad applications of these nanoscale architectures, especially the supramolecular gels derived from low molecular mass compounds, in fields such as optoelectronics, light harvesting, organic-inorganic hybrid materials, tissue engineering and regenerative medicine are being envisaged. This review attempts to present a succinct overview of the current state of research on functional nano-scale systems-the design, synthesis and applications of self-assembled nanomaterials "engineered" to carry out precise functions, with an emphasis on supramolecular gel phase materials

A self-assembled, luminescent europium cholate hydrogel: a novel approach towards lanthanide sensitization

We propose a new self-assembly based strategy for the design of novel lanthanide based luminescent materials. In this approach a europium hydrogel is prepared and sensitization is achieved by doping the gel with pyrene in a non-coordinated fashion

Research Journal of Pharmaceutical, Biological and Chemical Sciences 'Green' Synthesis of Silver Nanoparticles by Using Grape (Vitis vinifera) Fruit Extract: Characterization of the Particles and Study of Antibacterial Activity

ABSTRACT The synthesis of metal nanoparticles is a growing area for research due to its potentiality in the application and development of advanced technologies. In general, nanoparticles are synthesized by using chemical methods which are not eco-friendly. Here, we have used a fast, convenient and environment-friendly method for the synthesis of silver nanoparticles by reducing silver nitrate with fruit extract of grape (Vitis vinifera). Characterization of the metallic nanoparticles was done by UV-Vis Spectroscopy, Dynamic Light Scattering (DLS) and Energy Dispersive X-ray Spectroscopy (EDX). The particle size and lattice image of the silver nanoparticles was studied by Transmission Electron Microscopy (TEM). The antibacterial activity of these nanoparticles was studied against Bacillus subtilis and Escherichia coli. Growth curves of bacteria in presence of silver nanoparticles showed inhibition of growth suggesting antibacterial property of the nanoparticles

Molecular Imprinting of Luminescent Vesicles

Applying molecular imprinting techniques to the surface of functionalized unilammelar fluid vesicles allows the preparation of specific and high-affinity luminescent chemosensors. We have photopolymerized diacetylene containing vesicles in the presence of small peptides as templates yielding imprinted polydiacetylene (PDA) patches in the membrane. They serve as multivalent receptor sites with significantly increased rebinding affinity for the template. All binding sites are surface exposed and accessible for analyte binding. The presence of analytes is signaled with high sensitivity by emission intensity changes of amphiphilic carboxyfluorescein, which is coembedded into the fluid DOPC membrane. The merger of PDA imprinting with dynamic functionalized vesicles overcomes some of the current limitations of molecular imprinting in chemosensor design and may be applied to many different target analytes

Self-organization of multiple components in a steroidal hydrogel matrix: design, construction and studies on novel tunable luminescent gels and xerogels

The present work combines two rapidly growing research areas-functional supramolecular gels and lanthanide based hybrid materials. Facile hydrogel formation from several lanthanide(III) cholates has been demonstrated. The morphological and mechanical properties of these cholate gels were investigated by TEM and rheology. The hydrogel matrix was subsequently utilized for the sensitization of Tb(III) by doping a non-coordinating chromophore, 2,3-dihydroxynaphthalene (DHN), at micromolar concentrations. In the mixed gels of Tb(III)-Eu(III), an energy transfer pathway was found to operate from Tb(III) to Eu(III) and by utilizing this energy transfer, tunable multiple-color luminescent hydrogels were obtained. The emissive properties of the hydrogels were also retained in the xerogels and their suspensions in n-hexane were used for making luminescent coating on glass surface

Perfluoroalkyl bile esters: a new class of efficient gelators of organic and aqueous-organic media

A new class of fluorinated gelators derived from bile acids is reported. Perfluoroalkyl chains were attached to the bile acids through two different ester linkages and were synthesized following simple transformations. The gelation property of these derivatives is a function of the bile acid moiety, the spacer and the fluoroalkyl chain length. By varying these parameters, gels were obtained in aromatic hydrocarbons, DMSO and DMSO/DMF-H(2)O mixtures of different proportions. Several derivatives of deoxycholic and lithocholic acids were found to be efficient organogelators, while the reported bile-acid based organogelators are mostly derived from the cholic acid moiety. The efficient gelators among these compounds formed gels well below 1.0% (w/v) and hence they can be termed as supergelators. The mechanical properties of these gels could be modulated by changing either the bile acid moiety or by varying the length of the fluoroalkyl segment. The presence of CO(2)-philic perfluoroalkyl groups is also expected to enhance their solubility in supercritical CO(2) and hence these compounds are promising candidates for making aerogels