Vibrational analysis of d-PCL(530)/siloxane based hybrids doped with two lithium salts

Published online: 22 May 2013The present study has been focused on environmentally friendly sol-gel derived electrolytes based on a di-urethane cross-linked d-PCL(530)/siloxane network (where d represents di, PCL identifies the poly(ε–caprolactone) biopolymer and 530 is the average molecular weight in g.mol-1) doped with a wide range of concentration of lithium perchlorate (LiClO4) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). Fourier Transform Infrared and Raman (FT-IR and FT-Raman, respectively) spectroscopies have been applied to evaluate the extent of ionic association. Characteristic bands of the PCL(530) segments, of the urethane cross-links and of the anions have been examined to gain insight into the cation/biopolymer, cation/anion and cation/cross-link interactions. In both electrolyte systems “free” ions and contact ions have been identified. The addition of salt modifies the hydrogen-bonded array of the host matrix, causing the destruction/formation of the urethane/urethane aggregates.Fundação para a Ciência e a Tecnologia (FCT

The RM2 Nakagami Fading Channel Simulator

We propose a new Nakagami phase-envelope fading channel simulator that (i) allows for arbitrary real values of fading parameter, (ii) exactly matches the Nakagami first-order statistics, (iii) and closely matches the second-order statistics classically assigned to Nakagami fading. The proposed simulator is based on a cascade of two existing simulators-the random-mixture simulator and the rank-matching simulator. It combines the strenghts of these two simulators, outperforming them both.1252323233

Biological effects of extracts obtained from Stryphnodendron adstringens on Herpetomonas samuelpessoai

We report the effect of Stryphnodendron adstringens on the trypanosomatid Herpetomonas samuelpessoai. The parasites were grown at 28ºC in a chemically defined medium containing crude extract and fractions at concentrations from 100 to 5000 µg/ml obtained from S. adstringens. Concentrations of 500, 1000, 2500, and 5000 µg/ml both crude extract and semi-purified fraction progressively inhibited the protozoans' growth. At a concentration of 100 µg/ml, crude extract or a semi-purified (F3) fraction did not affect the growth of the protozoans. The F3-9 - F3-12 sub-fractions, at a concentration of 1000 µg/ml, also showed increased inhibitory activity on H. samuelpessoai. The IC50 of the crude extract and the F3 fraction were 538 and 634 µg/ml, respectively. Ultrastructural and enzymatic alterations in the trypanosomatids were also evaluated. H. samuelpessoai cultivated in the presence of IC50 crude extract showed considerable ultrastructural alterations, such as marked mitochondrial swelling with a large number of cristae and evident Golgi complex vesiculation, as observed by transmission electron microscopy. Cells exposed to 538 µg/ml of crude extract at 28ºC for 72 h, showed decreased activity of the enzyme succinate cytochrome c reductase, a typical mitochondrion marker, as compared to untreated cell

Ansiedade na gestação, prematuridade e baixo peso ao nascer: uma revisão sistemática da literatura Anxiety during pregnancy, prematurity, and low birth weight: a systematic literature review

O objetivo desta revisão �� examinar publicações que investigaram o efeito da ansiedade no maior risco de prematuridade e/ou baixo peso ao nascer. Os bancos de dados MEDLINE versão PubMed, BVS, CINAHL e HEALTHSTAR, referentes aos anos de 1966 a 2006, foram rastreados usando-se a combinação dos seguintes descritores: anxiety, pregnancy, low birth weight e prematurity. Foram localizados 13 estudos: 11 coortes, 1 transversal e 1 caso-controle. A maioria (7/13) dos estudos foi realizado nos Estados Unidos. Quatro estudos foram considerados de excelente qualidade, pois excluíram adolescentes e/ou mulheres acima de 34 anos, aferiram a ansiedade a partir do primeiro e/ou segundo trimestre de gestação, utilizaram escalas validadas para medir ansiedade, apresentaram perdas de seguimento inferiores a 30% e controlaram os mais importantes fatores de confusão. A ansiedade na gestação foi associada à prematuridade e/ou ao baixo peso ao nascer em oito estudos. Os valores de razão de chance e risco relativo variaram de 1,08 a 2,31. São necessários estudos cuidadosamente desenhados para esclarecer a relação entre ansiedade na gestação, prematuridade e baixo peso ao nascer, já que as evidências observadas ainda são contraditórias.<br>The purpose of this systematic literature review was to examine publications that had investigated the effect of anxiety on prematurity and/or low birth weight. The PubMed, BVS, CINAHL, and HEALTHSTAR databases, published from 1966 to 2006, were tracked using the following key words: "anxiety", "pregnancy", "low birth weight", and "prematurity". Thirteen studies were found: 11 cohorts, 1 cross-sectional, and 1 case-control. Most studies (7/13) were conducted in the United States. The most reliable results came from four studies, whose strengths were: exclusion of adolescents and/or women older than 34 years, studies that analyzed anxiety during the second and/or third trimester of pregnancy, used validated scales to measure anxiety, kept loss-to-follow-up rates below 30%, and applied adequate control of confounders. Anxiety during pregnancy was associated with prematurity and/or low birth weight in eight studies. Odds ratios and relative risks varied from 1.08 to 2.31. Carefully designed and well-conducted studies are still needed to clarify the relationship between anxiety during pregnancy, prematurity, and low birth weight considering that the accumulated evidence remains controversial