4 resultados para Absorción acústica
em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo (BDPI/USP)
Resumo:
OBJECTIVES: Causes may be found in most cases of acute pancreatitis, however no etiology is found by clinical, biological and imaging investigations in 30% of these cases. Our objective was to evaluate results from endoscopic ultrasonography (EUS) for diagnosis of gallbladder microlithiasis in patients with unexplained (idiopathic) acute pancreatitis. METHODS: Thirty-six consecutive non-alcoholic patients with diagnoses of acute pancreatitis were studied over a five-year period. None of them showed signs of gallstones on transabdominal ultrasound or tomography. We performed EUS within one week of diagnosing acute pancreatitis. Diagnosis of gallbladder microlithiasis on EUS was based upon findings of hyperechoic signals of 0.5-3.0 mm, with or without acoustic shadowing. All patients (36 cases) underwent cholecystectomy, in accordance with indication from the attending physician or based upon EUS diagnosis. RESULTS: Twenty-seven patients (75%) had microlithiasis confirmed by histology and nine did not (25%). EUS findings were positive in twenty-five. Two patients had acute cholecystitis diagnosed at EUS that was confirmed by surgical and histological findings. In two patients, EUS showed cholesterolosis and pathological analysis disclosed stones not detected by EUS. EUS diagnosed microlithiasis in four cases not confirmed by surgical treatment. In our study, sensitivity, specificity and positive and negative predictive values to identify gallbladder microlithiasis (with 95% confidence interval) were 92.6% (74.2-98.7%), 55.6% (22.7-84.7%), 86.2% (67.4-95.5%) and 71.4% (30.3-94.9%), respectively. Overall EUS accuracy was 83.2%. CONCLUSIONS: EUS is a very reliable procedure to diagnose gallbladder microlithiasis and should be used for the management of patients with unexplained acute pancreatitis. This procedure should be part of advanced endoscopic evaluation.
Resumo:
Neste artigo apresentamos uma descrição geral da física do violino, analisando os conceitos que lhes dão sustentação física e que revelam toda a riqueza e o potencial pedagógico do assunto. Destacamos as contribuições de físicos como Helmholtz, Savart, Raman e Saunders no esforço para descrever a vibração produzida pelo arco nas cordas, e por compreender as propriedades acústicas do instrumento. Descrevemos a função de cada uma das componentes do instrumento e discutimos a importância dos modos normais de vibração dos tampos e do cavalete na resposta acústica do violino. A ressonância acústica da caixa do violino (ressonância de Helmholtz) será discutida fazendo-se um paralelo entre osciladores mecânico, elétrico e acústico. Discutiremos a resposta acústica do violino e descreveremos a produção de seu som caraterístico, que resulta da forma de onda originada pela excitação das cordas pelo arco, influenciada pelas vibrações e ressonâncias do corpo do violino, seus tampos e o cavalete.
Resumo:
OBJECTIVE: To analyze household risk factors associated with high lead levels in surface dental enamel. METHODS: A cross-sectional study was conducted with 160 Brazilian adolescents aged 14-18 years living in poor neighborhoods in the city of Bauru, southeastern Brazil, from August to December 2008. Body lead concentrations were assessed in surface dental enamel acid-etch microbiopsies. Dental enamel lead levels were measured by graphite furnace atomic absorption spectrometry and phosphorus levels were measured by inductively coupled plasma optical emission spectrometry. The parents answered a questionnaire about their children's potential early (05 years old) exposure to well-known lead sources. Logistic regression was used to identify associations between dental enamel lead levels and each environmental risk factor studied. Social and familial covariables were included in the models. RESULTS: The results suggest that the adolescents studied were exposed to lead sources during their first years of life. Risk factors associated with high dental enamel lead levels were living in or close to a contaminated area (OR = 4.49; 95% CI: 1.69;11.97); and member of the household worked in the manufacturing of paints, paint pigments, ceramics or batteries (OR = 3.43; 95% CI: 1.31;9.00). Home-based use of lead-glazed ceramics, low-quality pirated toys, anticorrosive paint on gates and/or sale of used car batteries (OR = 1.31; 95% CI: 0.56;3.03) and smoking (OR = 1.66; 95% CI: 0.52;5.28) were not found to be associated with high dental enamel lead levels. CONCLUSIONS: Surface dental enamel can be used as a marker of past environmental exposure to lead and lead concentrations detected are associated to well-known sources of lead contamination.
Resumo:
Introducción. La leche humana es el primer alimento escogido para alimentar a los recién nacidos (RN), especialmente a los prematuros (RNPT y a los de peso muy bajo (RNMBP). Cuando esta leche no está disponible, deben ser recetadas fórmulas especializadas, que promuevan un crecimiento y desarrollo adecuados. El uso de los hidrolizados proteicos (HP) en la UTI neonatal ha sido promovido, debido al riesgo potencial que los RNPT/MBP presentan, por la inmadurez gastrointestinal, problemas de absorción e intolerancia alimentaria. Sin embargo, tales formulaciones no fueran elaboradas para atender las necessidades específicas de estos niños, y pueden, cuando son utilizadas, ocasionar un déficit nutricional. Objetivo. Comparar la progresión de la nutrición enteral (NE) (a través de la oferta de volumen, calorías y proteínas), la evolución ponderal, y las complicaciones clínicas entre recién nacidos de peso muy bajo (RNPMB) alimentados con fórmula para prematuros (FP) e hidrolizado proteico (HP) en la UTI neonatal. Casuística y métodos. Fueran estudiados dos grupos de RNPMB: grupo 1:13RNPMB con edad gestacional media de nacimiento de 30 semanas, peso medio de nacimiento de 1 167 gramos, que recibieron FP. Grupo 2:8 RN con edad gestacional media de nacimiento de 29 semanas, peso medio de nacimiento de 1 141 gramos, alimentados con HP. Las ofertas de volumen, la de calorías y la de proteínas fueran diariamente calculadas para todos los niños en ambos grupos. La nutrición parenteral (NP) que complementaría a la terapia nutricional en las primeras semanas, también fue calculada. Los RNMBP fueron pesados diariamente, por la mañana, en balanza digital (escala de 10 g) debidamente calibrada. El peso medio diario fue calculado hasta el dia 15 de vida. Fueron construidas curvas de crescimento, a través del polinomio de segundo grado para ambos grupos. Para el análisis estadístico se utilizó el test de medias. Resultados. ) La oferta media de volumen, calorías y proteínas fue mayos en la primera semana en el grupo 2, pero de una forma no significativa (p=0.38; 0.34 y 0.05, respectivamente). En las semanas subsequentes, no hubo diferencias significativas en la progresión de NE entre los grupos. No fueron observadas complicaciones clínicas, sólo ocurrieron dos casos de distensión abdominal en el grupo 1, pero no fueron caracterizados como enterocolitis necrosante (ECN). No hubo diferencias estadísticas relacionadas con el aumento de peso entre los dos grupos durante el periodo de estudio; sin embargo, el grupo 1 presentó una tendencia de mejor evolución. conclusión. La prograsión de la NE fue semejante con la utilización de los dos tipos de fórmulas, no feron encontradas diferencias en el aumento de peso de los grupos, y no hubo complicaciones clínicas en ninguno de ellos. No hubo ventajas en el uso del HP en la UTI neonatal; por tanto, no está indicado para RNPMB, sin disfunción intestinal, debido a que su composición nutricional no prevé las necesidades de este grupo de niños