Hydrogenated silicon fullerenes: effects of H on the stability of metal-encapsulated silicon clusters

Ab initio calculations of H interaction on Si12M, Si18M2 (M=Cr, Mo, and W), and Zr@Si(16) fullerene (f) show relatively weak binding of H in agreement with experimental results of H free Si12M and Si18M2 clusters. Adsorption of H enhances sp(3) bonding between the Si atoms, weakens the M-Si cage interactions, and leads to distortions in the cages. Si12CrH12 has 4 mu(B) magnetic moment in contrast to zero for Si12Cr. Removal of the M atom leads to stable empty cages of Si12H12, f-Si16H16, and f-Si20H20 with large highest occupied-lowest unoccupied molecular orbital gaps of 2.5-3.0 eV, making them attractive for optoelectronic applications.     

Bioremediation of soil contaminated with organic compounds with special reference to acrylonitrile

Enrichment of acrylonitrile (AN) degrading bacterial culture from contaminated soil resulted in the isolation of two cultures which were identified as gram negative small rods (C1) and gram positive cocci (C2). One of the cultures (C1) was identified as Citrobacter fruendii on the basis of biochemical and physiological tests. Both the cultures (C1 and C2) were able to utilize acrylonitrile up to a concentration of 2000 mg/l as the sole source of carbon and nitrogen. The studies also confirmed that the acrylonitrile contaminated soil when ploughed with well mixed AN degrading culture, diammonium phosphate and farmyard manure, could be completely remediated within two months from the date of soil amendment.     

A sharp estimate on the degree of approximation to functions of bounded variation by certain operators

Recently Guo^[2] introduced integrated Meyer-König and Zeller operators and studied the rate of convergence for function of bounded variation. In this note we give a sharp estimate for these operators.     

NONMARKET RESOURCE VALUATION: A BILEVEL OPTIMIZATION APPROACH

The social value of a common property/open access resource is in general different from the value attributed by individual users. Therefore, public intervention in the form of prices, quotas and marketable licenses has often been necessary to prevent overexploitation of such resources. This paper addresses the pricing issue. The existing mathematical programming studies in the resource economics literature suggest using the shadow price information obtained from an aggregate model where the sum of net returns to individual users and the management authority is maximized. When the policy maker's objective takes a different form, however, the shadow price strategy may result in a socially suboptimum or infeasible resource utilization. A bilevel optimization approach is proposed in this paper where the price of the resource is introduced as a policy variable and the optimizing behavior of individual users is considered as an explicit constraint in a global optimization problem. An empirical application of the proposed approach to the steady state management of a large scale irrigation system is presented.     

Grouping multi-item inventory using common cycle periods

Multi-item inventory control may be simplified by grouping items into subgroups with a common order cycle for all the items in each group. The methods provided in the literature for determination of the order cycle values are either suboptimal or computationally inefficient. This note proposes a procedure which finds the optimal values and is also computationally efficient.     

Electrochemical reduction of α,α′-Dibromo-dibenzylsulfone, -sulfoxide,and -sulfide

The electrochemical reduction of the title compounds in dimethylformamide affords in all cases stilbene as a major product, leading to the conclusion that cyclization to a three-membered ring containing sulfur is a common feature in these reductions. Other products isolated in the reductions help to shed light upon the course of the reactions.     

Intermediacy of bicyclo[2.2.1]hepteneone in the photolysis of bicyclo[2.2.2]octenediones

UV Irradiation of cyclohexane solution of bicyclo[2.2.2]octenediones led to facile extrusion of carbon monoxide to give substituted dihydrobiphenyls along with the dehydrogenated products. The inseparable mixtures on DDQ oxidation afforded the biphenyl derivatives. Isolation of an intermediate arising from the initial monodecarbonylation lends support to a proposed mechanistic rationalization.     

Main-chain liquid crystalline copolymers: synthesis and comparative study of the mesomorphic properties and non-linear optical properties

Linear main-chain polymers (P1, P2 and P3) have been synthesised and characterised. The polymers were designed to understand the rigidity of the mesogen’s linking groups and its effect on transition temperature. The liquid crystalline behaviour of these polymers was investigated using polarised optical microscopy and differential scanning calorimetry. All polymers exhibited phase transition on heating and cooling runs. The mesophase stability decreases with the decrease of rigidity of the second mesogen (P2>P1>P3). Similarly, the enthalpy and entropy changes are dependent on the rigidity of the second mesogen (Mesogen B). Polymer P1 undergoes photoisomerisation under UV-visible light irradiation and it attains a photo-stationary state at 275 s. This provides an opportunity to investigate the third-order non-linear optical properties. The non-linear behaviour of polymer P1 in chloroform presents a distinct deviation in a different concentration, where polymer P1 also exhibits a negative non-linear refractive index. Thus, polymer P1 can be used as a potential candidate for optical device applications such as optical limiters.     

1,2,3-Triazole tethered acetophenones: Synthesis,bioevaluation and molecular docking study

A small focused library of eighteen new 1,2,3-triazole tethered acetophenones has been efficiently prepared via click chemistry approach and evaluated for their antifungal and antioxidant activity. The antifungal activity was evaluated against five human pathogenic fungal strains: Candida albicans, Fusarium oxysporum, Aspergillus flavus, Aspergillus niger, and Cryptococcus neoformans. Among the synthesized compounds, 9c, 9i, and 9p found to be more potent antifungal agents that the reference standard. These 1,2,3-triazole based derivatives were also evaluated for antioxidant activity, and compound 9h was found to be the most potent antioxidant as compared to the standard drug. Furthermore, molecular docking study of the newly synthesized compounds was performed and results showed good binding mode in the active site of fungal C. albicans enzyme P450 cytochrome lanosterol 14a-demethylase. Moreover, the synthesized compounds were also analyzed for ADME properties and showed potential as good oral drug candidates.