Room temperature photoluminescence of tensile-strained Ge/Si0.13Ge0.87 quantum wells grown on silicon-based germanium virtual substrate

We report a room temperature study of the direct band gap photoluminescence of tensile-strained Ge/Si0.13Ge0.87 multiple quantum wells grown on Si-based germanium virtual substrates by ultrahigh vacuum chemical vapor deposition. Blueshifts of the luminescence peak energy from the Ge quantum wells in comparison with the Ge virtual substrate are in good agreement with the theoretical prediction when we attribute the luminescence from the quantum well to the c Gamma 1-HH1 direct band transition. The reduction in direct band gap in the tensile strained Ge epilayer and the quantum confinement effect in the Ge/Si0.13Ge0.87 quantum wells are directly demonstrated by room temperature photoluminescence.

Pr掺杂对Ce_(0.87)Sm_(0.13)O_(2-δ)结构及电性能的影响

采用溶胶-凝胶法合成Ce0.87Sm0.13-xPrxO2-δ(x=0.00,0.01,0.02)氧化物,通过X射线衍射、拉曼光谱、场发射扫描电镜对氧化物进行结构表征,利用交流阻抗谱测试电性能,并讨论了掺杂Pr对Ce0.87Sm0.13O2-δ微观结构和电性能的影响.结果表明,掺入少量Pr3+可减少或消除晶粒表面和晶界处的坑痕或孔隙,增加材料的致密性,从而降低材料的晶界电阻和电极界面电阻以及晶界电阻在总电阻中所占的比例,提高了材料的电导率.

Resultados de pesquisa de soja 1986/87.

Agrometeorologia; Entomologia; Fertilidade do solo e microbiologia; Fitopatologia; Genetica e melhoramento; Manejo da cultura; Plantas daninhas; Tecnologia de sementes; Metodos quantitativos; Difusao de tecnologia; Informacao e documentacao; Assessoria de imprensa.

Recomendacoes tecnicas para a cultura da soja no Parana 1986/87.

Investimentos em tecnologia: a nova realidade da nova agricultura; Manejo do solo; Clima; Cultivares; Populacao, densidade e epocas de semeadura; Instalacao da lavoura; Controle de plantas daninhas; Manejo de pragas; Controle de doencas; Colheita.

Yeast screens identify the RNA polymerase II CTD and SPT5 as relevant targets of BRCA1 interaction.

BRCA1 has been implicated in numerous DNA repair pathways that maintain genome integrity, however the function responsible for its tumor suppressor activity in breast cancer remains obscure. To identify the most highly conserved of the many BRCA1 functions, we screened the evolutionarily distant eukaryote Saccharomyces cerevisiae for mutants that suppressed the G1 checkpoint arrest and lethality induced following heterologous BRCA1 expression. A genome-wide screen in the diploid deletion collection combined with a screen of ionizing radiation sensitive gene deletions identified mutants that permit growth in the presence of BRCA1. These genes delineate a metabolic mRNA pathway that temporally links transcription elongation (SPT4, SPT5, CTK1, DEF1) to nucleopore-mediated mRNA export (ASM4, MLP1, MLP2, NUP2, NUP53, NUP120, NUP133, NUP170, NUP188, POM34) and cytoplasmic mRNA decay at P-bodies (CCR4, DHH1). Strikingly, BRCA1 interacted with the phosphorylated RNA polymerase II (RNAPII) carboxy terminal domain (P-CTD), phosphorylated in the pattern specified by the CTDK-I kinase, to induce DEF1-dependent cleavage and accumulation of a RNAPII fragment containing the P-CTD. Significantly, breast cancer associated BRCT domain defects in BRCA1 that suppressed P-CTD cleavage and lethality in yeast also suppressed the physical interaction of BRCA1 with human SPT5 in breast epithelial cells, thus confirming SPT5 as a relevant target of BRCA1 interaction. Furthermore, enhanced P-CTD cleavage was observed in both yeast and human breast cells following UV-irradiation indicating a conserved eukaryotic damage response. Moreover, P-CTD cleavage in breast epithelial cells was BRCA1-dependent since damage-induced P-CTD cleavage was only observed in the mutant BRCA1 cell line HCC1937 following ectopic expression of wild type BRCA1. Finally, BRCA1, SPT5 and hyperphosphorylated RPB1 form a complex that was rapidly degraded following MMS treatment in wild type but not BRCA1 mutant breast cells. These results extend the mechanistic links between BRCA1 and transcriptional consequences in response to DNA damage and suggest an important role for RNAPII P-CTD cleavage in BRCA1-mediated cancer suppression.

Las temperaturas mínimas en la zona del Alto Valle de Río Negro en el período 1960 - 87

p.159-162

'A terrible danger to the morals of the country': The Irish hospitals' sweepstake in Great Britain, 1930-87

This paper examines the importance of British contributions to the success of the Irish hospitals sweepstake. In its early years, up to three-quarters of these tickets were sold in Britain, bringing millions of pounds into Ireland annually to improve and expand the state's hospitals. The vast amount of money leaving Britain in this way angered the British government and forced it to introduce new legislation to curtail the activities of the Irish sweep. The paper will highlight the extent to which the success of the sweepstake depended on the market for tickets in Britain; the threat to the sweep's survival posed by the restriction of its activities in Britain after 1935; the role of the sweepstake controversy in exacerbating further already strained relations between Britain and the Irish Free State in the 1930s; how the success of the sweep raised the issue of legalising a British lottery; and the eventual decline of the sweepstake as a force in British gambling in the post-war years.