Electron transport in nanotube--molecular wire hybrids

We study contact effects on electron transport across a molecular wire sandwiched between two semi-infinite (carbon) nanotube leads as a model for nanoelectrodes. Employing the Landauer scattering matrix approach we find that the conductance is very sensitive to parameters such as the coupling strength and geometry of the contact. The conductance exhibits markedly different behavior in the two limiting scenarios of single contact and multiple contacts between the molecular wire and the nanotube interfacial atoms. In contrast to a single contact the multiple-contact configuration acts as a filter selecting single transport channels. It exhibits a scaling law for the conductance as a function of coupling strength and tube diameter. We also observe an unusual narrow-to-broad-to-narrow behavior of conductance resonances upon decreasing the coupling.Comment: 4 pages, figures include

Study of Correlation among total silica, free silica and HGI in different specific gravity fractions of coals from Karanpura coalfields and its impact in thermal power station

Coal samples from Balkundra, Bansgara, Hathidari, and Sounda block of Karanpura coalfields were wasthed at different specific gravity (1.40 to 1.80) and each gravity fraction is analysed for chemical composition of ash, Hardgrove Grindability Index (HGI) and other chemical properties with a focus on the correlation of free silica (a –quartz) with HGI. Quantitative data on quartz are important, as quartz endows coal with an abrasive propensity by virtue of its hardness (7.0 on Mohs hardness scale). Free silica is responsible for erosion of the boilers unit in thermal power stations and also responsible for abrasion effect in mining and grinding equipment. It was observed that with the increase in the value of free silica, HGI value decreases with some exception and in those cases it may be due to higher amount of fusinite in this coal as it has highest grindability value in comparison to other macerals. The data generated on total silica, free silica of coal ash and HGI of the coal studies have been subjected to regression and correlation analysis. Positive correlation have been found between free silica and HGI (R2 = 0.8

Physico-chemical investigations of the coal from East Bokaro coalfield (Muditoli block) - a case study

Detailed investigations with respect to chemical, petrological and carbonization characteristics have been carried on a single borehole coal core of Muditoli area of East Bokaro coalfield drilled by Geological Survey of India. The Muditoli block contains 29 uncorrelated seams as encountered in the single borehole. Total thickness of the coal is 118.25 meters within a depth range form 398.40 meters to 1164.50 meters as encountered in the borehole. All the seams are interbanded and wide variation in the seam thickness as is observed. The strata associated with the coal seams are coarse grained, medium grained and fine-grained sandstone. All these seams found in this borehole have shown excellent maturity due to deep seated nature. An increasing trend of carbon content and reflectance value with increasing depth are observed. The coal characteristic data along with the carbonization parameters indicate that coal is medium to prime coking in nature. However, the coking properties after 1000 meter depth are found to drop significantly. The poor coking properties of these coals (below 1000 meter) are also evidenced from carbon (dmmf) values which are more than 91.8%. If the reserve of the coal in this sector is goof enough and mining is technically and economically feasible then ths coal may be a good source of coking coal in future

Chemometrics Optimized Extraction Procedures, Phytosynergistic Blending and in vitro Screening of Natural Enzyme Inhibitors Amongst Leaves of Tulsi, Banyan and Jamun

Background: Tulsi, Banyan, and Jamun are popular Indian medicinal plants with notable hypoglycemic potentials. Now the work reports cherno-profiling of the three species with in-vitro screening approach for natural enzyme inhibitors (NEW against enzymes pathogenic for type 2 diabetes. Further along with the chemometrics optimized extraction process technology, phyto-synergistic studies of the composite polyherbal blends have also been reported. Objective: Chemometrically optimized extraction procedures, ratios of polyherbal composites to achieve phyto-synergistic actions, and in-vitro screening of NEls amongst leaves of Tulsi, Banyan, and Jamun. Materials and Methods: The extraction process parameters of the leaves of three plant species (Ficus benghalensis, Syzigium cumini and Ocimum sanctum) were optimized by rotatable central composite design of chemometrics so as to get maximal yield of bio-actives. Phyto-blends of three species were prepared so as to achieve synergistic antidiabetic and antioxidant potentials and the ratios were optimized by chemometrics. Next, for in vitro screening of natural enzyme inhibitors the individual leaf extracts as well as composite blends were subjected to assay procedures to see their inhibitory potentials against the enzymes pathogenic in type 2 diabetes. The antioxidant potentials were also estimated by DPPH radical scavenging, ABTS, FRAP and Dot Blot assay. Results: Considering response surface methodology studies and from the solutions obtained using desirability function, it was found that hydro-ethanolic or methanolic solvent ratio of 52.46 +/- 1.6 and at a temperature of 20.17 +/- 0.6 gave an optimum yield of polyphenols with minimal chlorophyll leaching. The species also showed the presence of glycosides, alkaloids, and saponins. Composites in the ratios of 1:1:1 and 1:1:2 gave synergistic effects in terms of polyphenol yield and anti-oxidant potentials. All composites (11 :1, 1:21, 2:1:1, 1:1:2) showed synergistic anti-oxidant actions, Inhibitory activities against the targeted enzymes expressed in terms of IC50 values have shown that hydro-ethanolic extracts in all cases whether individual species or composites in varying ratios gave higher IC50 values thus showing greater effectivity. Conclusion: Current research provides the state-of-the-art of search of NEls amongst three species by in-vitro assays which can be further utilized for bioactivity-guided isolations of such enzyme inhibitors. Further, it reports the optimized phyto-blend ratios so aster achieve synergistic anti-oxidative actions

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Not AvailablePotential antibacterial activity of berberine against multi drug resistant enterovirulent Escherichia coli isolated from yaks (Poephagus grunniens) with haemorrhagic diarrhoeaNot Availabl