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Made available in DSpace on 2014-10-09T12:23:41Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:57:36Z (GMT). No. of bitstreams: 1 00617.pdf: 4446323 bytes, checksum: 2472e6b6e02afc6e4ba94b64e17ccf87 (MD5) / Tese (Doutoramento) / IEA/T / Faculdade de Medicina, Universidade de Sao Paulo - FM/USP

Made available in DSpace on 2014-10-09T12:32:20Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:10:28Z (GMT). No. of bitstreams: 1 11282.pdf: 1648241 bytes, checksum: 1f0ef077bda3085781976b769a4136a9 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Made available in DSpace on 2014-10-09T12:32:20Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:10:28Z (GMT). No. of bitstreams: 1 11282.pdf: 1648241 bytes, checksum: 1f0ef077bda3085781976b769a4136a9 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

No description available.

Made available in DSpace on 2014-10-09T12:23:41Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:57:36Z (GMT). No. of bitstreams: 1 00617.pdf: 4446323 bytes, checksum: 2472e6b6e02afc6e4ba94b64e17ccf87 (MD5) / Tese (Doutoramento) / IEA/T / Faculdade de Medicina, Universidade de Sao Paulo - FM/USP

Diarrhoeal disease is a major cause of infant mortality in this and other developing countries. The assessment of the degree of dehydration in these children is often based on subjective findings alone. These have been shown to be inaccurate as an assessment of the degree of dehydration. Whole-body impedance (WBI) is a method of measuring total body water which is used to assess body composition. This WBI technology, which operates at a single frequency, has been applied to the assessment of dehydration in children with diarrhoeal disease. The normal range of WBI was determined on a group of normally hydrated children and was found to have a mean of 746 Ω, a standard deviation of 85 Ω and 95 % confidence interval for the mean from 720 Ω to 772 Ω. WBI did not depend on age, mass, height or sex. The WBI of a group of children dehydrated from infantile gastroenteritis was measured both before and after rehydration. The dehydrated group had a mean WBI on admission of 1089 Ω and a standard deviation of 149 Ω with a 95 % confidence interval for the mean from 950 Ω to 1109 Ω. This value was significantly greater than that of the normal group. The WBI of the dehydrated group after rehydration was not significantly different from the normal group. In addition a variable frequency bioimpedance analyser was designed and tested. It was found to have an error of less than 1 % over the frequency range 1 to 100 kHz. The device was evaluated on 11 normal and dehydrated children. Four dehydrated children were tested before and after rehydration and this data was compared to a standard electrical model for WBI. It was found that the model could represent the measured data over this frequency range. The extracellular resistive element of the model was mainly responsible for the changes seen during rehydration, suggesting that dehydration in gastroenteritis is mainly due to fluid loss from the ECF compartment.

Made available in DSpace on 2014-10-09T12:34:47Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:29Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Made available in DSpace on 2014-10-09T12:34:47Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:29Z (GMT). No. of bitstreams: 0 / Este trabalho teve como objetivos estabelecer os protocolos para o cálculo de incertezas de medição e a interpretação dos resultados de monitoração do Laboratório de Monitoração In Vivo (LMIV). Especificamente, o trabalho visou quantificar a contribuição dos fatores de influência para o cálculo de incertezas, e estabelecer a incerteza nas medidas. Foram utilizados dois detectores cintiladores de iodeto de sódio ativados com tálio (NaI:Tl) que possuem dimensões de 8x4\" (detector de corpo inteiro) e 3x3\" (detector de tireóide), um analisador multicanal EG&G Ortec, modelo 920E, e um microcomputador onde os espectros são adquiridos, analisados e armazenados com o auxílio do programa Renascence32, Ortec. As medições foram realizadas utilizando-se o objeto simulador antropomórfico do Alderson Research Labs. O radionuclídeo de interesse adotado para este estudo foi o 137Cs. Foram estudadas as influências dos fatores operador, geometria de medição, condições ambientais, flutuações eletrônicas com o tempo e baixa atividade. A análise das incertezas resultou em uma incerteza combinada relativa de 15,7% para o sistema 8x4\" e 9,8% para o sistema 3x3\". Estes valores foram obtidos seguindo os princípios recomendados no Guia para Expressão da Incerteza de Medição (GUM) da Joint Committee for Guides in Metrology (JCGM). / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

No description available.