With excitation energy above the Tauc selleck chemical gap, the emission band systematically blue-shifts

and broadens with decreasing silicon content, suggesting tail to tail recombination as the prevailing luminescence mechanism. With subgap excitation, the response is instead peaked at 1.7 eV independently of the stoichiometry, likely as an effect of the spatial fluctuations of the gap. In this case, excitation and emission selectively occur in the Si rich domains within the material, and direct band to band recombination is proposed as the possible dominant process. Another effect of the nonuniform material composition is likely the unusual S-shaped evolution of the integrated photoluminescence intensity versus temperature observed for the sample richest in Si. This behavior has been described with a phenomenological model including two thermally activated nonradiative processes and one electron trap energy level. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3575172]“
“Although a whole-cell pertussis vaccine was introduced in Pakistan in 1980, little is known about the pertussis prevalence and circulating strains in Pakistan. The aim of this study EPZ-6438 was to analyze Bordetella parapertussis isolates circulating between 2005 and 2009 in Pakistan and to compare them with those found in other countries during different periods. A total of 59 (7.35%) B.similar to parapertussis

isolates from 802 subjects (median age, 3 similar to years) from Pakistan, with pertussis-like symptoms were investigated. We carried out genotyping and DNA microarray analyses on these isolates and compared them with some international isolates of B.similar to parapertussis. We found that the allele for pertactin (prn) found in strains studied from

Pakistan was identical to the predominant type found in Europe. click here We showed that B.similar to parapertussis isolates circulating in Pakistan are part of the same pulsed-field gel electrophoresis group to those circulating in Finland during the period of 19822007. Finally, microarray analysis confirmed that the isolates collected in Pakistan, were quite similar to international strains. Overall, these results confirm that B.similar to parapertussis is extremely monomorphic. The high isolation rate of B.similar to parapertussis (7.35%) compared to Bordetella pertussis (0.5%) may suggest that the whole-cell vaccine used in Pakistan is effective against B.similar to pertussis (0.5% infections detected), but much less so against B.similar to parapertussis.”
“Each year in the past three decades has seen hundreds of thousands of runners register to run a major marathon. Of those who attempt to race over the marathon distance of 26 miles and 385 yards (42.195 kilometers), more than two-fifths experience severe and performance-limiting depletion of physiologic carbohydrate reserves (a phenomenon known as ‘hitting the wall’), and thousands drop out before reaching the finish lines (approximately 1-2% of those who start).