Electronic and optical properties of lead iodide

ABSTRACT: Lead iodide (PbI2) is a very important material with a technological applicability as a room-temperature radiation detector. It is a wide-band-gap semiconductor (Eg.2 eV) with high environmental stability efficiency. The performance of the detector cannot be fully understood unless its electronic and optical properties are determined. Recently, its band-gap energy and thermal properties were determined by photoacoustic spectroscopy. A single crystal of PbI2 was grown by the Bridgman method with the c-axis oriented perpendicular to the growth axis. The purpose of this work is to obtain the electronic structure of PbI2, its dielectric functions e 1 and e 2 by ellipsometry and theoretically by full-potential linear muffin-tinorbital ~FPLMTO! method, and the temperature dependence of the measured band-gap energy by optica absorption. The obtained Eg(T) can be fitted by two different methods, leading to Eg ~0 K! and Eg ~300 K!

Antenatal magnesium individual participant data international collaboration: assessing the benefits for babies using the best level of evidence (AMICABLE)

BACKGROUND: The primary aim of this study is to assess, using individual participant data (IPD) meta-analysis, the effects of administration of antenatal magnesium sulphate given to women at risk of preterm birth on important clinical outcomes for their child such as death and neurosensory disability. The secondary aim is to determine whether treatment effects differ depending on important pre-specified participant and treatment characteristics, such as reasons at risk of preterm birth, gestational age, or type, dose and mode of administration of magnesium sulphate. METHODS: Design: The Antenatal Magnesium Individual Participant Data (IPD) International Collaboration: assessing the benefits for babies using the best level of evidence (AMICABLE) Group will perform an IPD meta-analysis to answer these important clinical questions. Setting/Timeline: The AMICABLE Group was formed in 2009 with data collection commencing late 2010. Inclusion Criteria: Five trials involving a total 6,145 babies are eligible for inclusion in the IPD meta-analysis. Primary study outcomes: For the infants/children: Death or cerebral palsy. For the women: Any severe maternal outcome potentially related to treatment (death, respiratory arrest or cardiac arrest). DISUCSSION: Results are expected to be publicly available in 2012.C.A. Crowther, P.F. Middleton, L.M. Askie, L.W. Doyle, T.K. Bubner and M. Voyse

Thrombotic microangiopathy: A role for magnesium?

Despite advances in more recent years, the pathophysiology and especially treatment modalities of thrombotic microangiopathy (TMA) largely remain enigmatic. Disruption of endothelial homeostasis plays an essential role in TMA. Considering the proven causal association between magnesium and both endothelial function and platelet aggregability, we speculate that a magnesium deficit could influence the course of TMA and the related haemolytic uraemic syndrome and thrombotic thrombocytopenic purpura. A predisposition towards TMA is seen in many conditions with both extracellular and intracellular magnesium deficiency. We propose a rationale for magnesium supplementation in TMA, in analogy with its evidence-based therapeutic application in pre-eclampsia and suggest, based on theoretical grounds, that it might attenuate the development of TMA, minimise its severity and prevent its recurrence. This is based on several lines of evidence from both in vitro and in vivo data showing dose-dependent effects of magnesium supplementation on nitric oxide production, platelet aggregability and inflammation. Our hypothesis, which is further amenable to assessment in animal models before therapeutic applications in humans are implemented, could be explored both in vitro and in vivo to decipher the potential role of magnesium deficit in TMA and of the effects of its supplementation

Marcadores moleculares no câncer de pulmão: papel prognóstico e sua relação com o tabagismo Molecular markers in lung cancer: prognostic role and relationship to smoking

Estudos epidemiológicos têm demonstrado um nexo causal entre tabagismo e carcinoma de pulmão. Embora a maioria dos cânceres de pulmão esteja associada com tabagismo, somente uma minoria de grandes tabagistas desenvolve essa malignidade, o que leva ao conceito de que fatores genéticos afetam a susceptibilidade individual. As principais alterações moleculares no câncer de pulmão são: genes de supressão tumoral, proto-oncogenes e fatores de crescimento, atividade da telomerase e status de metilação de promotores. Fatores estimuladores da angiogênese (fator de crescimento endotelial vascular) e fatores relacionados à proliferação e apoptose de células tumorais (receptor para fator de crescimento epidérmico, p53, K-ras, retinoblastoma, BCL-2) são bem conhecidos. Vários desses fatores genéticos foram investigados, porém nenhum deles apresentou seletividade no que diz respeito à importância prognóstica ou eficácia terapêutica. Estratégias terapêuticas para o tratamento do câncer de pulmão devem considerar essas alterações genéticas precoces para promover o seu reparo ou eliminar as células tumorais.<br>Epidemiological studies have demonstrated a causal relationship between smoking and lung cancer. Although most lung cancer cases are linked to smoking, only a minority of heavy smokers develop lung cancer, leading to the notion that genetic factors affect individual susceptibility. The principal molecular changes in lung cancer are seen in tumor suppressor genes, proto-oncogenes, growth factors, telomerase activity, and methylation status of promoters. Well-known agents include angiogenesis-stimulating factors (such as vascular endothelial growth factor), as well as factors related to tumor cell proliferation and apoptosis (epidermal growth factor receptor, p53, K-ras, retinoblastoma and BCL-2). Several of these genetic factors have already been investigated, but no single parameter has yet presented sufficient selectivity regarding prognostic value or therapeutic efficacy. Treatment strategies to cure lung cancer should focus on these early genetic lesions in order to promote their repair or to eliminate these lung cancer cells