Fission fragment angular distributions in 16O+181Ta

Time of flight and energy of fission fragments were measured using pulsed beam. Fission fragment mass and energy integrated angular distributions were extracted. Fission fragment anisotropy was explained in the framework of saddle point model.     

The redox behavior of gem-dihalo compounds: 9,9-dibromofluorene, 9,9-dichlorofluorene and dichlorodiphenylmethane

The redox behavior of several gem-dihalo compounds has been examined at platinum and vitreous carbon electrodes in dimethylformamide. The reduction of 9,9-dichlorofluorene is initially an overall two-electron process which involves cleavage of chloride ion and the formation of 9-chlorofluorenyl anion. The final products and their distribution are then dependent upon the relative rates of reduction of the parent compound, nucleophilic attack of 9-chlorofluorenyl anion on the parent compound, and proton availability. If reaction by substitution is permitted to predominate, 9,9′-dichlorobifluorenyl results. This species is electroactive at the applied potential and undergoes reductive dechlorination to give bifluorenylidene. In contrast, if either the rate of reduction of 9,9-dichlorofluorene of the rate of protonation of 9-chlorofluorenyl anion exceeds the rate of substitution, the predominant product becomes 9-chlorofluorene. Reduction of this species then gives a mixture of fluorene and bifluorenyl when electrolysis is effected in an aprotic medium and fluorene when electrolysis is performed in the presence of diethyl malonate, a weak proton donor. Dichlorodiphenylmethane and 9,9-dibromofluorene also undergo reductive dehalogenation to give monomeric and dimeric products by pathways analogous to those observed for dichlorofluorene. In the case of dibromofluorene, however, the product distribution is also potential dependent since the intermediate 9-bromofluorenyl radical may not be reduced at the applied potential. No evidence was obtained in these studies to support previous claims of carbenes and/or carbene radical anions in these reductions.     

An Experimental Study of Reactions of Co and H2 in a Continuous Flow Microwave Discharge Reactor

The reactions of CO/H2 mixtures in a flowing microwave (2450 MHz) reactor system have been studied experimentally. This versatile microwave plasma source catalyzes the reactions selectively to products, mainly methane and acetylene. For reaction times of 0.1 to 0.5 seconds in the pressure range of 10 to 90 torr conversions of CO to hydrocarbons ranged from 4 to 19%. Electric and magnetic field configurations in the reactor, i. e. various electromagnetic modes, appear to have only minor effects on the chemical reactions. It was observed that the conversion of CO to hydrocarbons is enhanced by high ratios of H2/CO. Based on analysis of experimental data, hydrogen radical production appears to be the controlling mechanism for producing both methane and acetylene.     

Epitaxial ternary nitride thin films prepared by a chemical solution method

It is indispensable to use thin films for many technological applications. This is the first report of epitaxial growth of ternary nitride AMN2 films. Epitaxial tetragonal SrTiN2 films have been successfully prepared by a chemical solution approach, polymer-assisted deposition. The structural, electrical, and optical properties of the films are also investigated.     

Incorporation of sparingly soluble species in mesostructured surfactant-polymer films

Recently we have investigated the formation of novel thick, solid, mesostructured films of polymer/surfactant mixtures which form spontaneously at the air-solution interface. Here we report studies of the effect of adding a series of sparingly soluble species to the precursor solution, to alter the mesostructure of cetyltrimethylammonium bromide/polyethylenimine films and to investigate the incorporation of small molecules within the films. Small-angle neutron scattering confirmed that cyclohexane and decane evenly swell the micelles in film forming solutions, while cyclohexanol extends the prolate micelles along their long axis. Although the presence of these additives in solution did not greatly affect the formation of the film, it was observed that they did influence the structure of the films. Films produced with decane consisted of a cubic phase rather the conventional 2-D hexagonal phase, whilst both cyclohexane and cyclohexanol enhance the level of ordering in low MW polymer films. Benzene was found to have no significant effect on the film.     

AMP-Activated Protein Kinase: A Target for Drugs both Ancient and Modern

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Highlights? AMP-activated protein kinase (AMPK) is a sensor of cellular energy status ? Drugs that activate AMPK have potential in type 2 diabetes and in cancer ? Many existing drugs and xenobiotics (e.g., metformin, salicylate) activate AMPK ? Most, but not all, AMPK-activating xenobiotics inhibit mitochondrial function