347 research outputs found

    Remarkable co-catalyst effects on the enantioselective hydrogenation of unfunctionalised enamines : both enantiomers of product from the same enantiomer of catalyst

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    During studies on the enantioselective hydrogenation of unfunctionalised enamines, a very surprising switch in enantiopreference was observed; [((R,R)-Et-DUPHOS)-Rh(COD)]BF4 hydrogenates an enamine to give (R)-amine with up to 73% ee, but when iodine is added as a co-catalyst, the (S)-amine is formed with up to 61% ee. Mechanistic studies implicate a protonation-iminium ion reduction pathway.PostprintPeer reviewe

    Is profitable to play in Spanish Soccer First Division?

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    El artículo presenta la primera fase de un estudio del fútbol español, cuyo objetivo es averiguar si es rentable jugar en Primera División de fútbol (1ª) para cualquier equipo profesional y si todos los clubes de 2ªA deberían aspirar al ascenso. Se comparan resultados en la población seleccionada y en dos grupos de la misma: equipos que se han mantenido en 1ª y equipos ascensor. Se examinan mediante análisis exploratorio de datos resultados económicos y deportivos, se identifican factores que influyen en su variación y se clasifican los clubes según dichos factores. También se determina la influencia de ascensos y descensos en los resultados. Se deduce que los equipos ascensor obtienen peores resultados aun jugando en la misma liga. Además, a su estabilidad económico financiera le afecta más el ascenso y descenso continuo que el mantenerse en una categoría concreta. Finalmente, que la “gestión del miedo” no siempre conduce a una mejor clasificación y añade tensión financiera. Se concluye que no a todos los clubes les conviene militar en 1ª división de fútbol, que ésta debe reestructurarse y se debe reforzar la 2ªAThe paper presents the first phase of a Spanish football study. The aim is to determine if it is profitable to play in 1ª D league for any professional team and if all clubs in 2ª A division should aspire to climb. Various results are compared in the selected population and also in two groups identified: equipment that have remained in 1ªD and “elevator teams”. The economics and sports results are examined by exploratory data analysis. We identify factors that are influence in change and the teams are classified according to these factors. Finally the influence of promotion and relegation in these results is determined. It follows that the "Fear Management" doesn’t always lead to better classification and adds financial stress, “elevator equipment” that perform worse even playing in the same league and its economic and financial stability will most affect the rise and decline that continued the stay in a particular category. We conclude: not all clubs suit them military in 1ª, it would be to restructure and strengthen the 2ª

    A novel selective 11β-hydroxysteroid dehydrogenase type 1 inhibitor prevents human adipogenesis

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    Glucocorticoid excess increases fat mass, preferentially within omental depots; yet circulating cortisol concentrations are normal in most patients with metabolic syndrome (MS). At a pre-receptor level, 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) activates cortisol from cortisone locally within adipose tissue, and inhibition of 11β-HSD1 in liver and adipose tissue has been proposed as a novel therapy to treat MS by reducing hepatic glucose output and adiposity. Using a transformed human subcutaneous preadipocyte cell line (Chub-S7) and human primary preadipocytes, we have defined the role of glucocorticoids and 11β-HSD1 in regulating adipose tissue differentiation. Human cells were differentiated with 1·0 μM cortisol (F), or cortisone (E) with or without 100 nM of a highly selective 11β-HSD1 inhibitor PF-877423. 11β-HSD1 mRNA expression increased across adipocyte differentiation (P<0·001, n=4), which was paralleled by an increase in 11β-HSD1 oxo-reductase activity (from nil on day 0 to 5·9±1.9 pmol/mg per h on day 16, P<0·01, n=7). Cortisone enhanced adipocyte differentiation; fatty acid-binding protein 4 expression increased 312-fold (P<0·001) and glycerol-3-phosphate dehydrogenase 47-fold (P<0·001) versus controls. This was abolished by co-incubation with PF-877423. In addition, cellular lipid content decreased significantly. These findings were confirmed in the primary cultures of human subcutaneous preadipocytes. The increase in 11β-HSD1 mRNA expression and activity is essential for the induction of human adipogenesis. Blocking adipogenesis with a novel and specific 11β-HSD1 inhibitor may represent a novel approach to treat obesity in patients with MS

    Polarization-based characterization of laser thermal treatment on biological tissue

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    The field of biomedical optics is promising in medical praxis. The study of laser thermal treatment and polarization-based characterization of tissue under it can be utilized in the correction of certain disorders with good results

    The weighted independent domination problem: ILP model and algorithmic approaches

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    This work deals with the so-called weighted independent domination problem, which is an N P -hard combinatorial optimization problem in graphs. In contrast to previous theoretical work from the liter- ature, this paper considers the problem from an algorithmic perspective. The first contribution consists in the development of an integer linear programming model and a heuristic that makes use of this model. Sec- ond, two greedy heuristics are proposed. Finally, the last contribution is a population-based iterated greedy algorithm that takes profit from the better one of the two developed greedy heuristics. The results of the compared algorithmic approaches show that small problem instances based on random graphs are best solved by an efficient integer linear programming solver such as CPLEX. Larger problem instances are best tackled by the population-based iterated greedy algorithm. The experimental evaluation considers random graphs of different sizes, densities, and ways of generating the node and edge weights

    The Weighted Independent Domination Problem: ILP Model and Algorithmic Approaches

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    This work deals with the so-called weighted independent domination problem, which is an NPNP-hard combinatorial optimization problem in graphs. In contrast to previous work, this paper considers the problem from a non-theoretical perspective. The first contribution consists in the development of three integer linear programming models. Second, two greedy heuristics are proposed. Finally, the last contribution is a population-based iterated greedy metaheuristic which is applied in two different ways: (1) the metaheuristic is applied directly to each problem instance, and (2) the metaheuristic is applied at each iteration of a higher-level framework---known as construct, merge, solve \& adapt---to sub-instances of the tackled problem instances. The results of the considered algorithmic approaches show that integer linear programming approaches can only compete with the developed metaheuristics in the context of graphs with up to 100 nodes. When larger graphs are concerned, the application of the populated-based iterated greedy algorithm within the higher-level framework works generally best. The experimental evaluation considers graphs of different types, sizes, densities, and ways of generating the node and edge weights
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