Estudo do efeito térmico sobre os níveis de impurezas em semicondutores

The temperature dependence of impurity levels in semiconductors is a very interesting problem in the domain of deep levels impurities. Its evidence in experimental results is reported by many authors. However, the interpretation on theoretical basis requires sophisticated models. In this paper we propose a very simple model that allows to extract the relevant parameters from the experiment without needing heavy computation.O estudo da dependência da posição dos níveis de energia das impurezas profundas em semicondutores com a temperatura é um problema bastante interessante, e sua evidência experimental é discutida por vários autores. Neste artigo propomos um modelo teórico bastante simples, a partir do conhecimento da secção de choque de fotoionização e de alguns parametros associados aos fónons, para o entendimento deste comportamento

Idealized PPARγ-Based Therapies: Lessons from Bench and Bedside

The incidence of type 2 (T2D) diabetes and other chronic conditions associated with insulin resistance is increasing at an alarming rate, underscoring the need for effective and safe therapeutic strategies. Peroxisome-proliferator-activated receptor gamma (PPARγ) has emerged as a critical regulator of glucose homeostasis, lipid homeostasis, and vascular inflammation. Currently marketed drugs targeting this receptor, the thiazolidinediones (TZDs), have proven benefits on insulin resistance and hyperglycemia associated with T2D. Unfortunately, they have been associated with long-term unfavorable effects on health, such as weight gain, plasma volume expansion, bone loss, cardiovascular toxicity, and possibly cancer, and these safety concerns have led to reduced interest for many PPARγ ligands. However, over the last years, data from human genetic studies, animal models, and studies with ligands have increased our understanding of PPARγ's actions and provided important insights into how ligand development strategies could be optimized to increase effectiveness and safety of PPARγ-based therapies

Coffee consumption has no acute effects on glucose metabolism in healthy men : a randomized crossover clinical trial

We investigate the effect of coffee (caffeinated and decaffeinated) on glucose effectiveness and insulin sensitivity using the stable isotope minimal model protocol with oral glucose administration in healthy men

Factors associated with mortality among patients with central venous catheter-related bloodstream infection in an intensive care unit

Central venous catheterization is a common practice in the management of critically ill patients and is associated with various complications, such as Bloodstream Infections (BSI), which are major determinants of increased morbidity, mortality and healthcare expenses. Few studies have addressed factors that predict mortality in patients with this complication. The aim of this study was to investigate factors associated with mortality in patients with Central Venous Catheter (CVC)-related BSI in an intensive care unit of a tertiary care hospital in the Federal District, Brazil. This was a retrospective and observational study, in which all CVC-related BSI that occurred between January 2008 and December 2010 were reviewed. We obtained demographic, clinical, biochemical and microbiological data from medical records and investigated its association with mortality during ICU stay. There were 4,504 ICU admissions during the study period and 68 were complicated by CVC-related BSI (4.09 per 1000 catheter-days), most due to gram-negative organisms (45.6%). Overall mortality was 59.7%. Death risk was significantly associated with mechanical ventilation (OR 27.8, 95% CI 3.28-250, p<0.001), the mean number of invasive devices other than the CVC (1.44 Vs 2.37 in controls Vs cases, p<0.001) and increased serum levels of urea (mean value of 44.2 mg dL-1 in survivors vs. 73.9 mg dL-1 in non-survivors, p = 0.001). Mortality was not associated with other clinical or biochemical features, neither with microbiological variables, although lethality was high among patients with gram-positive infections (77% Vs 58.33% for fungi and 54.83% for gram-negative). CVC-related BSI was associated with high absolute mortality, which was predicted by mechanical ventilation and a higher number of invasive devices other than the CVC. Knowledge of local factors predictive of mortality is critical for planning strategies to reduce death risk associated with this complication

Inserção de dispositivo intrauterino durante a cesárea em mulheres sem aconselhamento contraceptivo pré-natal : lições de um país com elevada taxa de cesárea

Objetivo O momento da admissão para o parto pode ser considerado inapropriado para oferecer o dispositivo intrauterino (DIU) para mulheres sem aconselhamento contraceptivo pré-natal. Entretanto, em países com elevadas taxas de cesáreas e aconselhamento contraceptivo deficiente, essa estratégia pode reduzir o risco de gestações não programadas e cesáreas repetidas. Métodos Estudo de coorte envolvendo 100 mulheres sem aconselhamento contraceptivo pré-natal. A inserção de DIU pós-dequitação foi oferecida após a admissão para o parto e indicação de cesárea. As taxas de continuidade com o DIU, perfuração uterina e endometrite foram avaliadas após 6 semanas e 6 meses, e a proporção de mulheres que continuaram com o DIU após 6 meses foi analisada em relação ao número de cesáreas prévias. Resultados Noventa e sete mulheres completaram o seguimento. A taxa de permanência do DIU foi de 91% em 6 semanas e 83,5% em 6 meses. A taxa de expulsão/ remoção nas primeiras 6 semanas foi não foi diferente daquela observada entre 6 emanas e 6 meses (9 vs 9,1%, respectivamente). Houve dois casos de endometrite (2,1%), e nenhum caso de perfuração uterina. Entre as 81mulheres que permaneceram como DIU após 6 meses, 31% haviam sido submetidas a apenas uma cesárea, em que o DIU foi inserido, 44% a 2, e 25% a 3 ou mais cesáreas. Conclusão Dois terços das mulheres que continuaram com o DIU após 6 meses haviam sido submetidas a 2 ou mais cesáreas. Considerando que oferecer a tentativa de parto vaginal após duas oumais cesáreas prévias é incomum, é possível que a oferta do DIU na admissão para o parto possa reduzir o risco de cesáreas repetidas e de seus riscos associados.Objective Themoment of admission for deliverymay be inappropriate for offering an intrauterine device (IUD) to women without prenatal contraception counseling. However, in countries with high cesarean rates and deficient prenatal contraception counseling, this strategy may reduce unexpected pregnancies and repeated cesarean sections. Methods This was a prospective cohort study involving 100 women without prenatal contraception counseling. Postplacental IUD was offered after admission for delivery and placed during cesarean. The rates of IUD continuation, uterine perforation, and endometritis were assessed at 6 weeks and 6 months, and the proportion of women continuing with IUD at 6 months was assessed with respect to the number of previous cesareans. Results Ninety-seven women completed the follow-up. The rate of IUD continuation was 91% at 6 weeks and 83.5% at 6 months. The expulsion/removal rate in the first 6 weeks was not different from that between 6 weeks and 6 months (9 vs 9.1%, respectively). There were 2 cases of endometritis (2.1%), and no case of uterine perforation. Among 81 women continuing with intrauterine device after 6-months, 31% had undergone only the cesarean section in which the IUD was inserted, 44% had undergone 2 and 25% had undergone 3 or more cesarean sections. Conclusion Two thirds of the women who continued with IUD at 6 months had undergone 2 ormore cesarean sections. Since offering trial of labor is unusual after 2 or more previous cesareans, we believe that offering IUD after admission for delivery may reduce the risk of repeated cesarean sections and its inherent risks

Indução da lactação em mãe por útero de substituição : efeitos na concentração de prolactina, produção láctea e satisfação materna

Relato de caso de mãe por útero de substituição, de 39 anos de idade, submetida a indução da lactação por exposição sequencial a drogas galactogogas (metoclopramida e domperidona), estimulação mamilar mecânica com bomba elétrica, e sucção pelo recém-nascido. O estudo teve como objetivo analisar os efeitos de cada etapa do protocolo na concentração sérica de prolactina, no volume de secreção láctea e na satisfação materna. A concentração sérica de prolactina e a produção láctea não apresentaram mudanças significativas. Entretanto, a mãe foi capaz de amamentar a criança por quatro semanas, e manifestou grande satisfação com a experiência. Como conclusão, no contexto de maternidade por útero de substituição, o aleitamento materno parece promover benefícios emocionais, não necessariamente relacionados ao aumento do volume de leite.Case report of a 39-year-old intended mother of a surrogate pregnancy who underwent induction of lactation by sequential exposure to galactagogue drugs (metoclopramide and domperidone), nipple mechanical stimulation with an electric pump, and suction by the newborn. The study aimed to analyze the effect of each step of the protocol on serum prolactin levels, milk secretion and mother satisfaction, in the set of surrogacy. Serum prolactin levels and milk production had no significant changes. Nevertheless, themother was able to breastfeed for four weeks, and expressed great satisfaction with the experience. As a conclusion, within the context of a surrogate pregnancy, breastfeeding seems to bring emotional benefits not necessarily related to an increase in milk production

Sedentary behavior : a key component in the interaction between an integrated lifestyle approach and cardiac autonomic function in active young men

This study aimed to verify the association between autonomic cardiac function (CAF) and the integration of caloric expenditure by physical activity (PA) intensity, sedentary behavior (SB), and sleep quality (PSQI) in active young men. Thirty-five subjects were included, and caloric expenditure in moderate-to-vigorous and light-intensity PA, SB, and PSQI were assessed using questionnaires. Heart rate variability (HRV) was recorded for short periods of time in the supine and orthostatic positions. Multiple linear regression was realized unadjusted and adjusted for covariables, such as age, body mass index, and fat mass. No adjusted analysis indicated that, in the supine position, there were negative associations between the SB and the TP, HF, and NorHF indices, and positive associations between SB and NorLF and LF/HF. In the orthostatic position, an interaction between SB and NorLF was found. Significance of proportion with the TP, HF, and LF/HF indices was confirmed. When adjusted, for the supine position, negative interactions were documented between SB and the TP as well as the HF indices, and between PSQI and the LF/HF index, with interference under the HF and LF/HF indices. Finally, our findings indicate that the proposed approach interacts with CAF, and SB is significantly related to CAF in young active men

Depressão com início após o parto: estudo de corte prospectivo em mulheres submetidas à cesárea eletiva em Brasília, Brasil

OBJETIVO: Foi determinar a prevalência de sintomas depressivos em uma amostra de puérperas da cidade de Brasília, Brasil, discriminando os casos com surgimento após o parto daqueles já presentes durante a gestação. MÉTODOS: Estudo de corte prospectivo. Amostragem por conveniência de pacientes que seriam submetidas à cesariana eletiva em dois hospitais privados. Como instrumento para avaliar os sintomas depressivos, foi utilizada a Escala de Depressão Pós-natal de Edimburgo, com ponto de corte >13, aplicada momentos antes do parto e quatro a oito semanas após o nascimento da criança. RESULTADOS: Das 107 mulheres que completaram o estudo, 11 (10,3%) apresentaram sintomas depressivos significativos na gestação e 12 (11,2%) no período pós-parto. Das 12 pacientes com sintomas no pós-parto, 6 já tinham os sintomas durante a gestação, de modo que 5,6% da amostra teve depressão com início após o parto. A frequência global de depressão foi significativamente maior entre as mulheres solteiras em comparação com mulheres casadas (p=0,04) por causa principalmente da maior frequência de mulheres solteiras apresentando sintomas depressivos persistentes, antes e depois do parto (p=0,002). O risco de depressão não foi influenciado pela idade, paridade e escolaridade. CONCLUSÃO: As mulheres com depressão reconhecida no período pós-parto compõem um grupo heterogêneo, no qual o quadro pode ter tido início antes da gestação, durante a gestação ou após o parto. Na amostra estudada, metade dos casos de depressão reconhecida após o parto já apresentava os sintomas no final da gestação. Uma vez que a depressão que surge antes e após o parto pode ter etiologia diferente e, portanto, apresentar resposta ao tratamento diferente, os clínicos e pesquisadores devem estar atentos a essa possibilidade.PURPOSE: It was to determine the prevalence of depressive symptoms in a sample of puerperal women from Brasília, Brazil, distinguishing cases with onset after delivery from those already present during pregnancy. METHODS: A prospective cohort study with convenience sampling of patients submitted to elective cesarean section at two private hospitals. As an instrument for assessing depressive symptoms, the Edinburgh Postnatal Depression Scale with cutoff >13 was applied shortly before delivery and four to eight weeks after childbirth. RESULTS: Among the 107 women who completed the study, 11 (10.3%) had significant depressive symptoms during pregnancy and 12 (11.2%) during the postpartum period. Among the 12 patients with postpartum symptoms, 6 had symptoms during pregnancy, so that 5.6% of the sample had postpartum onset of depression. The higher overall frequency of depression was significantly among single women than among married women (p=0.04), a fact mainly due to a higher frequency of single women experiencing persistent depressive symptoms both before and after delivery (p=0.002). The risk of depression was not influenced by age, parity or educational level. CONCLUSION: Women with depression identified during the postpartum period comprise a heterogeneous group, in which symptoms may have started before pregnancy, during pregnancy or after childbirth. In this sample, half of the postpartum depression cases already presented symptoms during late pregnancy. Since depression can arise before and after childbirth, it may have different etiologies and, therefore, a different response to treatment, a possibility that should be considered by clinicians and researchers

Associação do polimorfismo de nucleotídeo único rs7903146 no locus do TCF7L2 com diabetes tipo 2 em indivíduos brasileiros

OBJECTIVE:To investigate the association of the T allele of the single nucleotide polymorphism (SNP) rs7903146 of TCF7L2 with the occurrence of T2D in a sample of subjects followed up at the Brasilia University Hospital. SUBJECTS AND METHODS: The SNP rs7903146 of TCF7L2 was genotyped by allele-specific PCR in 113 patients with known T2D and in 139 non-diabetic controls in Brasilia, Brazil. RESULTS:We found that the T allele of the SNP rs7903146 of TCF7L2 was significantly associated with T2D risk (odds ratio of 3.92 for genotype TT in the recessive genetic model, p = 0.004 and 1.5 for T allele, p = 0.032). CONCLUSION:These results reinforce previous findings on the consistent association of this genetic factor and the risk of T2D in populations of diverse ethnic backgrounds. Arq Bras Endocrinol Metab. 2012;56(8):479-84OBJETIVO: Investigar a associação do alelo T do polimorfismo de nucleotídeo único (SNP) rs7903146 do TCF7L2 com a ocorrência de DM2 em uma amostra de indivíduos acompanhados no Hospital Universitário de Brasília. SUJEITOS E MÉTODOS: O SNP 7903146 do TCF7L2 foi genotipado por PCR alelo-específica em 113 pacientes portadores de DM2 e em 139 controles não diabéticos em Brasília, Brasil. RESULTADOS: Foi observada associação significativa do alelo T do SNP rs7903146 do TCF7L2 com a ocorrência de DM2 (razão de chances de 3,92 para o genótipo TT utilizando o modelo genético recessivo, p = 0,003; e de 1,5 para o alelo T, p = 0,032). CONCLUSÃO: Esse resultado reforça os achados prévios de associação consistente desse fator genético com o risco de diabetes em populações de origens étnicas diversas. Arq Bras Endocrinol Metab. 2012;56(8):479-8

Lack of association between the CC genotype of the rs7903146 polymorphism in the TCF7L2 gene and rheumatoid arthritis

INTRODUÇÃO: TCF7L2 é um fator de transcrição envolvido na sinalização Wnt/beta-catenina e tem uma variante conhecida por associar-se consistentemente com o risco de diabetes tipo 2. Alguns estudos também relataram sua associação com o risco de alguns tipos de câncer. OBJETIVO: Como essa via pode também estar envolvida na fisiopatologia de outras doenças inflamatórias crônicas, tais como artrite reumatoide, o objetivo deste estudo foi investigar o efeito do polimorfismo rs7903146 do gene TCF7L2 na gravidade da artrite reumatoide em uma população brasileira. PACIENTES E MÉTODOS: Esse polimorfismo foi genotipado em 208 pacientes com artrite reumatoide e em 104 controles saudáveis. Analisou-se também a associação desse polimorfismo com história de tabagismo, classe funcional e indicadores radiológicos de gravidade da doença. RESULTADOS: A distribuição dos genótipos CC, CT e TT do polimorfismo rs7903146 do gene TCF7L2 não diferiu entre pacientes e controles, nem se encontrou qualquer associação entre o genótipo e os indicadores de gravidade da doença ou história de tabagismo. Quando os dados foram avaliados usando-se o modelo dominante, no qual portadores dos genótipos CT e TT foram agrupados, observou-se um aumento do alelo T em pacientes com fator reumatoide positivo e erosões, embora não significativo. A frequência do alelo T também estava aumentada nos pacientes com classe funcional II quando comparados àqueles com classe I (P = 0,032). CONCLUSÃO: É possível que o pequeno número de pacientes incluído neste estudo tenha dificultado achados adicionais. Outros estudos são, portanto, necessários para que se investigue o papel das variantes do gene TCF7L2 no risco de artrite reumatoide e sua gravidade.INTRODUCTION: TCF7L2 is a transcription factor involved in Wnt/beta-catenin signaling and which has a variant known to be consistently associated with type 2 diabetes risk and some studies have also indicated its association with risk of certain types of cancer. OBJECTIVE: Since this pathway may be involved in the pathophysiology of other chronic inflammatory diseases such as rheumatoid arthritis, we aimed to investigate the effect of TCF7L2 polymorphism rs7903146 on rheumatoid arthritis severity in a Brazilian population. PATIENTS AND METHODS: This polymorphism was genotyped in 208 patients with rheumatoid arthritis and in 104 healthy controls. We also analyzed the association of this polymorphism to smoking history, functional status classification and radiological indicators of disease severity. RESULTS: The distribution of CC, CT and TT genotypes of SNP rs7903146 of the TCF7L2 gene was not different between patients and controls, and no association between the genotype and indicators of disease severity or smoking history was found. When data were evaluated using the dominant model, in which carriers of the CT and TT genotypes were grouped, an increase in the T allele was observed in patients positive for rheumatoid factor and erosions, although this was not significant. The frequency of T allele was also increased in patients with functional class II compared to class I (P = 0.032). CONCLUSION: It is possible that the small number of patients included in this study may have restrained additional findings. Further studies are therefore needed to investigate the role of TCF7L2 gene variants in the risk of rheumatoid arthritis and its severity