1,175 research outputs found
Synthesis and thermal behaviour of an amorphous solid polymer electrolyte
In this study the synthesis of an amorphous polymer network, poly[oxymethylene-oligo(oxyethylene)], designated as aPEO, is described. This polymer has been characterized by gel permeation chromatography, thermal analysis, conductivity measurements, evaluation of electrochemical stability and nuclear magnetic resonance spectroscopy. The synthetic procedure developed permits partial fractionation of the product of the polymerization reaction. This linear macromolecule appears to be a promising polymer for application in batteries and electrochromic devices since it provides access to an amorphous polymer structure with good mechanical properties and promising electrochemical behavior.Fundação para a Ciência e a Tecnologia (FCT
Síndrome de Cushing na gravidez: uma visão geral
Cushing's syndrome (CS) during pregnancy is a rare condition with fewer than 150 cases reported in the literature. Adrenal adenomas were found to be the commonest cause, followed by Cushing's disease. The gestation dramatically affects the maternal hypothalamic-pituitary-adrenal axis, resulting in increased hepatic production of corticosteroid-binding globulin (CBG), increased levels of serum, salivary and urinary free cortisol, lack of suppression of cortisol levels after dexamethasone administration and placental production of CRH and ACTH. Moreover, a blunted response of ACTH and cortisol to exogenous CRH may also occur. Therefore, the diagnosis of CS during pregnancy is much more difficult. Misdiagnosis of CS is also common, as the syndrome may be easily confused with preeclampsia or gestational diabetes. Because CS during pregnancy is usually associated with severe maternal and fetal complications, its early diagnosis and treatment are critical. Surgery is the treatment of choice for CS in pregnancy, except perhaps in the late third trimester, with medical therapy being a second choice. There does not seem to be a rationale for supportive treatment alone.A ocorrência de síndrome de Cushing (SC) durante a gravidez é rara, com menos de 150 casos reportados na literatura. Os adenomas adrenais parecem ser a causa mais comum seguidos da doença de Cushing. A gestação afeta de maneira dramática o eixo hipotálamo-hipófise-adrenal materno resultando em aumento da produção hepática da globulina ligadora de corticosteróides (CBG), aumento dos níveis séricos, salivares e livres urinários de cortisol, falta de supressão do cortisol após administração de dexametasona e produção placentária de CRH e ACTH. Além disso, pode também ocorrer bloqueio da resposta do ACTH e do cortisol ao CRH exógeno. Assim, o diagnóstico de SC durante a gravidez torna-se muito mais difícil. A falha em diagnosticar SC é também comum, já que a síndrome pode ser facilmente confundida com pré-eclampsia ou diabetes gestacional. Uma vez que a SC de ocorrência na gravidez é usualmente associada com graves complicações materno-fetais, seu diagnóstico e tratamento precoces tornam-se críticos. A cirurgia é o tratamento de escolha para a SC na gravidez, exceto, talvez, no final do 3º trimestre, sendo o tratamento medicamentoso a segunda escolha. Não parece haver nenhum arrazoado para o tratamento de suporte isoladamente.Federal University of Pernambuco Hospital das Clínicas Division of Endocrinology and MetabolismHospital Getúlio Vargas Pernambuco University Medical School Division of Endocrinology and MetabolismFederal University of São Paulo Department of Medicine Division of Endocrinology and MetabolismUNIFESP, Department of Medicine Division of Endocrinology and MetabolismSciEL
Linking extreme waves, coastal boulders and lichenometry
Tsunamis and storms cause considerable coastal flooding, numerous fatalities, destruction of structures, and erosion. The characterization of energy and frequency associated with each wave contribute to the risk assessment in coastal regions. Coastal boulder deposits represent a physical proof of extreme inundation and allow us to study the effects of marine floods further back in time than instrumental and historical records. Age estimation of these deposits is challenging due to lack of materials (such as sand, shells, corals, or organic matter) that retain information about the passage of time. Lichenometry, a simple age estimation method, which is cost-effective, quick to apply, and non-destructive, is here proposed as a solution. A lichen growth model for a calcium-tolerant lichen species was developed and used to estimate the age of a boulder deposit related to extreme marine inundation(s) in Portugal. Estimated ages indicate several very recent events (<700 years) for most of the boulders’ stabilization and agree with results obtained with optically stimulated luminescence of marine sands found beneath boulders. Frequent and recent boulder transport implies a storm-origin for this deposit. These conclusions contrast with other works describing identical deposits that are attributed to paleotsunamis. This study presents a methodology using lichenometry as a successful alternative for age estimation in rocky coastal settings. These results offer an alternative explanation for coastal boulder deposits found on the west coast of Portugal.info:eu-repo/semantics/publishedVersio
Distal mummification of all limbs-an odd presentation of multiple myeloma
info:eu-repo/semantics/publishedVersio
Variability of boundary layer processes for the metropolitan area of São Paulo during winter
As variações espaciais e temporais da Camada Limite planetária (CLP) da Área Metropolitana da cidade de São Paulo (RMSP) durante o período de 23 de julho a 15 de Agosto de 1999 são estudas utilizando dados de um Sodar Doppler. RMSP (λ = 23º34’ S e φ = 46º44’ W) está numa altitude de 800 m acima do nível médio do mar, localizada 60 km à noroeste do oceano Atlântico, limitada por cadeias de montanhas ao norte, tendo uma orografia complexa e configura-se numa ilha de calor urbana.Este trabalho tem o objetivo de entender o impacto da urbanização sobre os processos de CLP particularmente durante a estação de inverno. Um número de diferentes tipos de experimentos estiveram em operação durante uma campanha de inverno organizada pelo IAG-USP. O Sodar Doppler fornece dados sobre (i) função estrutura de temperatura, CT2, (ii) velocidade do vento horizontal, u, (iii) velocidade do vento vertical, w, (iv) desvios padrão do vento horizontal e vertical, σu, σv e σw, e (v) altura da inversão de temperatura, Zi.A análise dos dados fornecidos pelo Sodar mostra claramente as variações desses parâmetros em alturas indo de 50 m até 1500 m com intervalos de 50 m num intervalo de tempo de 15 minutos. Existe grande variação desses parâmetros com a altura.O aumento noturno no campo do vento horizontal com a altura é bem marcado indicando a quase ausência de transporte vertical de momento horizontal durante a noite em condições estáveis. Durante as horas da manhã a aceleração na velocidade do vento é evidente. O aumento anormal em Zi durante a noite sob condições estáveis prevalece durante o inverno com valores mais altos em agosto do que em julho
Root Decomposition of Elephant Grass Pastures Grazed at Different Management Intensities
Grazing management may alter chemical composition of plant components affecting nutrient cycling. Among pasture management tools, adjustment of stocking rate (SR) and N fertilization have potential to affect nutrient cycling in the grassland ecosystem (Dubeux et al. 2007). Excreta from grazing animal and litter are the two major pathways of nutrient return on grazed pastures (Thomas 1992). Fertilization and SR may alter these pathways by different forms. Increasing fertilization generally increases pasture net primary productivity. Stocking rate affects different pasture and animal responses. Regarding nutrient cycling, increasing SR will likely increase proportion of nutrient returned through excreta as opposed to litter, increasing as a result nutrient losses (Dubeux et al. 2006). Root system may also be affected by management intensity. Frequent defoliation and low plant nutrition level may reduce root biomass (Richards 1993) and affect its decomposition. This study evaluated the effect of different SR´s and N fertilization levels on the decomposition of elephant grass roots
Consumo voluntário e ganho de peso de carneiros alimentados com dietas contendo diferentes quantidades de ácidos graxos poli-insaturados.
Efeito da adição de ácidos graxos poli-insaturados na dieta sobre a cinética espermática do sêmen de carneiros.
Efeito da adição de ácidos graxos poli-insaturados na dieta sobre aspectos quanti-qualitativos do sêmen de carneiros.
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