Objetivo: Estudar o efeito da monitorização contínua da oximetria de pulso (SpO2) durante o teste de caminhada de 6 minutos (TC6m), na detecção da hipoxemia induzida pelo exercício, em pacientes com sintomas respiratórios. Métodos: Os pacientes realizaram testes de função pulmonar e TC6m. A saturação e a freqüência cardíaca foram determinadas por um oxímetro de pulso e os dados transferidos simultaneamente para um computador através de telemetria. Comparamos a menor saturação atingida durante o teste com os valores da SpO2 obtidos imediatamente após o TC6m. Também foram comparadas as diferenças clínico funcionais dos pacientes agrupados de acordo com a presença de dessaturação (SpO2 repouso – SpO2 no exercício 4%) e SpO2 88%. Resultados: Foram estudados 452 pacientes (236 homens, 61 ± 13 anos). A capacidade vital forçada (CVF), o volume expiratório forçado no primeiro segundo (VEF1), a relação VEF1/CVF e a capacidade de difusão pulmonar (DCO) foram respectivamente 65,8 ± 18,6% do previsto, 52,6 ± 23,7% do previsto, 62,8 ± 18,8% e 51,7 ± 20,9% do previsto. A média da SpO2 mínima registrada com auxílio de telemetria durante o TC6m foi de 89,9 ± 6,5% e da SpO2 no final do teste foi de 91,1 ± 6,5% (p<0,001). Em 241 pacientes (53,3%) ocorreu dessaturação no TC6m. Foram observados dois padrões diferenciados de dessaturação durante o exercício: um grupo de pacientes dessaturou no início do TC6m e recuperou a SpO2 antes do final do mesmo (57 pacientes, 23,7% dos pacientes que dessaturaram) e o outro grupo apresentou queda da SpO2 persistente até o final do exercício. A SpO2 basal e os valores de função pulmonar foram significativamente mais altos no grupo de pacientes com o primeiro padrão de dessaturação. A SpO2 foi 88% em 148 pacientes; em 26 destes (17,6%) níveis de SpO2 88% foram detectados somente durante o TC6m. Conclusão: Nosso estudo demonstra que a mensuração contínua da SpO2 durante o TC6m é melhor que a mensuração da SpO2 imediatamente após o teste para detectar dessaturação induzida por exercício. / Objective: To study the effect of continuous measurement of pulse oximetry (SpO2) during six-minute walk test (6MWT) on detection of exercise induced hypoxemia in patients with respiratory complaints. Methods: Patients performed lung function tests and 6MWT. SpO2 and pulse rate were obtained by a pulse oximeter and continuously transferred to a computer using telemetry. The lowest saturation reached during the test was compared with the SpO2 measured immediately after the 6MWT. We also compared functional and clinical differences of patients grouped according to desaturation (rest SpO2 - exercise SpO2 4%) and SpO2 88%. Results: We studied 452 patients (236 men, 61 ± 13 years old). Mean forced vital capacity (FCV), forced expiratory volume in 1 s (FEV1), FEV1/FCV and pulmonary diffusion capacity (DLCO) were 65.8 ± 18.6% of predicted, 52.6 ± 23.7% of predicted, 62.8 ± 18.8% and 51.7 ± 20.9% of predicted, respectively. Mean of lowest SpO2 registered using telemetry during 6MWT was 89.9% ± 6.5% and at the end of test 91.1% ± 6.5% (p<0.001). Desaturation was observed in 241 patients (53.3%). There were two different patterns of desaturation: SpO2 decrease at the beginning of the 6MWT with recovery before the test end (57 patients, 23.7% of the patients with desaturation) and SpO2 decrease maintained at the end of exercise. Rest SpO2 and lung function values were significantly higher in patients with the first desaturation pattern. SpO2 88% was observed in 148 patients; in 26 of these cases (17.6%) SpO2 88% levels were only detected during the 6MWT. Conclusion: Continuous SpO2 measuring is better than SpO2 measurement performed immediately after 6MWT in detecting exercise induced desaturation.

Introdução: Pacientes com fibrose cística (FC) comumente apresentam pronunciadas alterações em vias aéreas inferiores, obstrução crônica de vias aéreas superiores, tosse noturna e uso de múltiplas medicações. Desta maneira, estão predispostos a apresentar diminuição da qualidade do sono e distúrbios respiratórios durante o sono. Embora a hipoxemia noturna seja considerada comum e sua identificação relevante no manejo da FC, atualmente ainda restam dúvidas sobre os preditores de dessaturação durante o sono nesta população. Objetivos: 1) Avaliar os distúrbios do sono em uma amostra de pacientes adultos com FC comparando-os com controles saudáveis e 2) Determinar os melhores preditores de dessaturação no sono em pacientes com FC e uma saturação periférica de oxigênio (SpO2) em vigília ≥90%. Métodos: Estudo transversal, com coleta de dados prospectiva, onde foram avaliados pacientes adultos com FC estáveis clinicamente e controles saudáveis pareados por idade e sexo. Todos os indivíduos realizaram uma polissonografia de noite inteira e preencheram a Escala de Sonolência de Epworth (ESE) e o Questionário de Qualidade de Sono de Pittsburgh (PSQI). Os pacientes com FC realizaram função pulmonar, teste de caminhada de 6 minutos (TC6M) e ecocardiografia. Estes dados foram correlacionados com os achados polissonográficos. Resultados: Foram avaliados 51 pacientes com FC (idade média de 25,1 ± 6,7 anos e volume expiratório forçado no primeiro segundo - VEF1 - médio de 57,7 ± 24,7% do previsto) e 25 controles saudáveis. Latências para o início do sono e para o sono REM, eficiência do sono e percentual de estágios do sono não diferiram significativamente entre os grupos. Contudo, pacientes com FC apresentaram maior índice de microdespertares durante o sono (12,1 vs. 8,9; p=0,02) e escores mais elevados na ESE (8,2 vs. 5,6; p=0,002) e no PSQI (6,0 vs. 2,7; p<0,001) em relação aos controles. O índice de apneia-hipopnéia (IAH) foi semelhante entre pacientes com FC e controles e apenas dois pacientes com FC (3,9%) apresentaram critérios polissonográficos para apneia obstrutiva do sono. A dessaturação da oxihemoglobina durante o sono foi significativamente mais frequente nos pacientes com FC comparado aos controles (29,4% vs. 0%; p<0,001). Os pacientes com FC que apresentaram dessaturação no sono tiveram valores mais baixos de SpO2 em vigília e ao final do TC6M, pior função pulmonar e valores mais elevados de pressão sistólica de artéria pulmonar. Em um modelo de regressão logística, identificou-se a SpO2 em vigília como o melhor preditor independente de dessaturação no sono nos pacientes com FC (p<0,001). A SpO2 em vigília <94% apresentou uma sensibilidade, especificidade, valor preditivo positivo e negativo para dessaturação no sono de, respectivamente, 93,3%, 100%, 100% e 97,3%. Conclusões: Pacientes adultos com FC apresentam diminuição subjetiva da qualidade do sono a despeito de uma arquitetura do sono pouco alterada. A dessaturação no sono é comum nos pacientes com FC a despeito de apresentarem uma SpO2 em vigília preservada; não está associada a apneia obstrutiva do sono e pode ser predita acuradamente por uma SpO2 em vigília <94%. / Introduction: Cystic fibrosis (CF) patients may be predisposed to poor sleep quality and sleep disordered breathing due to upper and lower airway abnormalities, chronic cough and use of multiple medications. Though nocturnal hypoxia is considered to be common and its identification relevant for the management of CF, nowadays questions remain about the predictors for sleep desaturation in this population. Objectives: To evaluate sleep parameters in a sample of adult CF patients comparing them with healthy controls and to determine the best predictors of sleep desaturation in CF patients with awake resting peripheral oxygen saturation (SpO2) ≥90%. Methods: In a cross-sectional study, with data collected prospectively, clinically stable adult CF patients and age-matched healthy controls underwent an overnight polysomnography and answered the Epworth sleepiness scale (ESS) and the Pittsburgh Sleep Quality Index (PSQI). CF patients had their pulmonary function, six-minute walk test (6MWT) and echocardiography assessed and correlated with polysomnographic findings. Results: Fifty-one CF patients (mean age 25.1 ± 6.7 years; mean FEV1 57.7 ± 24.7% of predicted) and 25 age-matched controls were assessed. CF patients and control subjects had similar sleep latencies, sleep efficiency and percentage of sleep stages. However, CF patients had a higher arousal index during sleep (12.1 vs. 8.9; p=0.02) and had higher ESS (8.2 vs. 5.6; p=0.002) and PSQI (6.0 vs. 2.7; p<0.001) scores than controls. The apnea-hypopnea index was similar in both groups and only two CF patients (3.9%) fulfilled criteria to obstructive sleep apnea. Sleep desaturation was significantly more common in CF patients (29.4% vs 0%; p<0.001). The CF patients who presented sleep desaturation had lower values of awake SpO2 at rest and at the end of 6MWT, worse pulmonary function status and higher pulmonary arterial systolic pressure. In a logistic regression model, we observed that awake resting SpO2 was the single best variable associated with sleep desaturation in CF population (p<0.001). The awake SpO2<94% had a sensitivity, specificity, positive and negative predictive value to sleep desaturation of, respectively, 93.3%, 100%, 100% and 97.3%. Conclusions: CF patients had a worse subjective sleep quality despite small changes in sleep architecture in comparison with age-matched healthy controls. In nonhypoxic, adult CF patients, sleep desaturation is common, is not associated with obstructive sleep apnea and can be accurately predict by awake resting SpO2 <94%.

abstract: The dissimilatory reduction of nitrate, or denitrification, offers the potential of a sustainable, cost effective method for the non-disruptive mitigation of earthquake-induced soil liquefaction. Worldwide, trillions of dollars of infrastructure are at risk for liquefaction damage in earthquake prone regions. However, most techniques for remediating liquefiable soils are either not applicable to sites near existing infrastructure, or are prohibitively expensive. Recently, laboratory studies have shown the potential for biogeotechnical soil improvement techniques such as microbially induced carbonate precipitation (MICP) to mitigate liquefaction potential in a non-disruptive manner. Multiple microbial processes have been identified for MICP, but only two have been extensively studied. Ureolysis, the most commonly studied process for MICP, has been shown to quickly and efficiently induce carbonate precipitation on particle surfaces and at particle contacts to improve the stiffness, strength, and dilatant behavior of liquefiable soils. However, ureolysis also produces copious amounts of ammonium, a potentially toxic byproduct. The second process studied for MICP, denitrification, has been shown to precipitate carbonate, and hence improve soil properties, much more slowly than ureolysis. However, the byproducts of denitrification, nitrogen and carbon dioxide gas, are non-toxic, and present the added benefit of rapidly desaturating the treated soil. Small amounts of desaturation have been shown to increase the cyclic resistance, and hence the liquefaction resistance, of liquefiable soils. So, denitrification offers the potential to mitigate liquefaction as a two-stage process, with desaturation providing short term mitigation, and MICP providing long term liquefaction resistance. This study presents the results of soil testing, stoichiometric modeling, and microbial ecology characterization to better characterize the potential use of denitrification as a two-stage process for liquefaction mitigation. / Dissertation/Thesis / Doctoral Dissertation Civil and Environmental Engineering 2016

abstract: Microbially induced calcium carbonate precipitation (MICP) is attracting increasing attention as a sustainable means of soil improvement. While there are several possible MICP mechanisms, microbial denitrification has the potential to become one of the preferred methods for MICP because complete denitrification does not produce toxic byproducts, readily occurs under anoxic conditions, and potentially has a greater carbonate yield per mole of organic electron donor than other MICP processes. Denitrification may be preferable to ureolytic hydrolysis, the MICP process explored most extensively to date, as the byproduct of denitrification is benign nitrogen gas, while the chemical pathways involved in hydrolytic ureolysis processes produce undesirable and potentially toxic byproducts such as ammonium (NH4+). This thesis focuses on bacterial denitrification and presents preliminary results of bench-scale laboratory experiments on denitrification as a candidate calcium carbonate precipitation mechanism. The bench-scale bioreactor and column tests, conducted using the facultative anaerobic bacterium Pseudomonas denitrificans, show that calcite can be precipitated from calcium-rich pore water using denitrification. Experiments also explore the potential for reducing environmental impacts and lowering costs associated with denitrification by reducing the total dissolved solids in the reactors and columns, optimizing the chemical matrix, and addressing the loss of free calcium in the form of calcium phosphate precipitate from the pore fluid. The potential for using MICP to sequester radionuclides and metal contaminants that are migrating in groundwater is also investigated. In the sequestration process, divalent cations and radionuclides are incorporated into the calcite structure via substitution, forming low-strontium calcium carbonate minerals that resist dissolution at a level similar to that of calcite. Work by others using the bacterium Sporosarcina pasteurii has suggested that in-situ sequestration of radionuclides and metal contaminants can be achieved through MICP via hydrolytic ureolysis. MICP through bacterial denitrification seems particularly promising as a means for sequestering radionuclides and metal contaminants in anoxic environments due to the anaerobic nature of the process and the ubiquity of denitrifying bacteria in the subsurface. / Dissertation/Thesis / M.S. Engineering 2013

Introdução: Pacientes com fibrose cística (FC) comumente apresentam pronunciadas alterações em vias aéreas inferiores, obstrução crônica de vias aéreas superiores, tosse noturna e uso de múltiplas medicações. Desta maneira, estão predispostos a apresentar diminuição da qualidade do sono e distúrbios respiratórios durante o sono. Embora a hipoxemia noturna seja considerada comum e sua identificação relevante no manejo da FC, atualmente ainda restam dúvidas sobre os preditores de dessaturação durante o sono nesta população. Objetivos: 1) Avaliar os distúrbios do sono em uma amostra de pacientes adultos com FC comparando-os com controles saudáveis e 2) Determinar os melhores preditores de dessaturação no sono em pacientes com FC e uma saturação periférica de oxigênio (SpO2) em vigília ≥90%. Métodos: Estudo transversal, com coleta de dados prospectiva, onde foram avaliados pacientes adultos com FC estáveis clinicamente e controles saudáveis pareados por idade e sexo. Todos os indivíduos realizaram uma polissonografia de noite inteira e preencheram a Escala de Sonolência de Epworth (ESE) e o Questionário de Qualidade de Sono de Pittsburgh (PSQI). Os pacientes com FC realizaram função pulmonar, teste de caminhada de 6 minutos (TC6M) e ecocardiografia. Estes dados foram correlacionados com os achados polissonográficos. Resultados: Foram avaliados 51 pacientes com FC (idade média de 25,1 ± 6,7 anos e volume expiratório forçado no primeiro segundo - VEF1 - médio de 57,7 ± 24,7% do previsto) e 25 controles saudáveis. Latências para o início do sono e para o sono REM, eficiência do sono e percentual de estágios do sono não diferiram significativamente entre os grupos. Contudo, pacientes com FC apresentaram maior índice de microdespertares durante o sono (12,1 vs. 8,9; p=0,02) e escores mais elevados na ESE (8,2 vs. 5,6; p=0,002) e no PSQI (6,0 vs. 2,7; p<0,001) em relação aos controles. O índice de apneia-hipopnéia (IAH) foi semelhante entre pacientes com FC e controles e apenas dois pacientes com FC (3,9%) apresentaram critérios polissonográficos para apneia obstrutiva do sono. A dessaturação da oxihemoglobina durante o sono foi significativamente mais frequente nos pacientes com FC comparado aos controles (29,4% vs. 0%; p<0,001). Os pacientes com FC que apresentaram dessaturação no sono tiveram valores mais baixos de SpO2 em vigília e ao final do TC6M, pior função pulmonar e valores mais elevados de pressão sistólica de artéria pulmonar. Em um modelo de regressão logística, identificou-se a SpO2 em vigília como o melhor preditor independente de dessaturação no sono nos pacientes com FC (p<0,001). A SpO2 em vigília <94% apresentou uma sensibilidade, especificidade, valor preditivo positivo e negativo para dessaturação no sono de, respectivamente, 93,3%, 100%, 100% e 97,3%. Conclusões: Pacientes adultos com FC apresentam diminuição subjetiva da qualidade do sono a despeito de uma arquitetura do sono pouco alterada. A dessaturação no sono é comum nos pacientes com FC a despeito de apresentarem uma SpO2 em vigília preservada; não está associada a apneia obstrutiva do sono e pode ser predita acuradamente por uma SpO2 em vigília <94%. / Introduction: Cystic fibrosis (CF) patients may be predisposed to poor sleep quality and sleep disordered breathing due to upper and lower airway abnormalities, chronic cough and use of multiple medications. Though nocturnal hypoxia is considered to be common and its identification relevant for the management of CF, nowadays questions remain about the predictors for sleep desaturation in this population. Objectives: To evaluate sleep parameters in a sample of adult CF patients comparing them with healthy controls and to determine the best predictors of sleep desaturation in CF patients with awake resting peripheral oxygen saturation (SpO2) ≥90%. Methods: In a cross-sectional study, with data collected prospectively, clinically stable adult CF patients and age-matched healthy controls underwent an overnight polysomnography and answered the Epworth sleepiness scale (ESS) and the Pittsburgh Sleep Quality Index (PSQI). CF patients had their pulmonary function, six-minute walk test (6MWT) and echocardiography assessed and correlated with polysomnographic findings. Results: Fifty-one CF patients (mean age 25.1 ± 6.7 years; mean FEV1 57.7 ± 24.7% of predicted) and 25 age-matched controls were assessed. CF patients and control subjects had similar sleep latencies, sleep efficiency and percentage of sleep stages. However, CF patients had a higher arousal index during sleep (12.1 vs. 8.9; p=0.02) and had higher ESS (8.2 vs. 5.6; p=0.002) and PSQI (6.0 vs. 2.7; p<0.001) scores than controls. The apnea-hypopnea index was similar in both groups and only two CF patients (3.9%) fulfilled criteria to obstructive sleep apnea. Sleep desaturation was significantly more common in CF patients (29.4% vs 0%; p<0.001). The CF patients who presented sleep desaturation had lower values of awake SpO2 at rest and at the end of 6MWT, worse pulmonary function status and higher pulmonary arterial systolic pressure. In a logistic regression model, we observed that awake resting SpO2 was the single best variable associated with sleep desaturation in CF population (p<0.001). The awake SpO2<94% had a sensitivity, specificity, positive and negative predictive value to sleep desaturation of, respectively, 93.3%, 100%, 100% and 97.3%. Conclusions: CF patients had a worse subjective sleep quality despite small changes in sleep architecture in comparison with age-matched healthy controls. In nonhypoxic, adult CF patients, sleep desaturation is common, is not associated with obstructive sleep apnea and can be accurately predict by awake resting SpO2 <94%.

Objetivo: Estudar o efeito da monitorização contínua da oximetria de pulso (SpO2) durante o teste de caminhada de 6 minutos (TC6m), na detecção da hipoxemia induzida pelo exercício, em pacientes com sintomas respiratórios. Métodos: Os pacientes realizaram testes de função pulmonar e TC6m. A saturação e a freqüência cardíaca foram determinadas por um oxímetro de pulso e os dados transferidos simultaneamente para um computador através de telemetria. Comparamos a menor saturação atingida durante o teste com os valores da SpO2 obtidos imediatamente após o TC6m. Também foram comparadas as diferenças clínico funcionais dos pacientes agrupados de acordo com a presença de dessaturação (SpO2 repouso – SpO2 no exercício 4%) e SpO2 88%. Resultados: Foram estudados 452 pacientes (236 homens, 61 ± 13 anos). A capacidade vital forçada (CVF), o volume expiratório forçado no primeiro segundo (VEF1), a relação VEF1/CVF e a capacidade de difusão pulmonar (DCO) foram respectivamente 65,8 ± 18,6% do previsto, 52,6 ± 23,7% do previsto, 62,8 ± 18,8% e 51,7 ± 20,9% do previsto. A média da SpO2 mínima registrada com auxílio de telemetria durante o TC6m foi de 89,9 ± 6,5% e da SpO2 no final do teste foi de 91,1 ± 6,5% (p<0,001). Em 241 pacientes (53,3%) ocorreu dessaturação no TC6m. Foram observados dois padrões diferenciados de dessaturação durante o exercício: um grupo de pacientes dessaturou no início do TC6m e recuperou a SpO2 antes do final do mesmo (57 pacientes, 23,7% dos pacientes que dessaturaram) e o outro grupo apresentou queda da SpO2 persistente até o final do exercício. A SpO2 basal e os valores de função pulmonar foram significativamente mais altos no grupo de pacientes com o primeiro padrão de dessaturação. A SpO2 foi 88% em 148 pacientes; em 26 destes (17,6%) níveis de SpO2 88% foram detectados somente durante o TC6m. Conclusão: Nosso estudo demonstra que a mensuração contínua da SpO2 durante o TC6m é melhor que a mensuração da SpO2 imediatamente após o teste para detectar dessaturação induzida por exercício. / Objective: To study the effect of continuous measurement of pulse oximetry (SpO2) during six-minute walk test (6MWT) on detection of exercise induced hypoxemia in patients with respiratory complaints. Methods: Patients performed lung function tests and 6MWT. SpO2 and pulse rate were obtained by a pulse oximeter and continuously transferred to a computer using telemetry. The lowest saturation reached during the test was compared with the SpO2 measured immediately after the 6MWT. We also compared functional and clinical differences of patients grouped according to desaturation (rest SpO2 - exercise SpO2 4%) and SpO2 88%. Results: We studied 452 patients (236 men, 61 ± 13 years old). Mean forced vital capacity (FCV), forced expiratory volume in 1 s (FEV1), FEV1/FCV and pulmonary diffusion capacity (DLCO) were 65.8 ± 18.6% of predicted, 52.6 ± 23.7% of predicted, 62.8 ± 18.8% and 51.7 ± 20.9% of predicted, respectively. Mean of lowest SpO2 registered using telemetry during 6MWT was 89.9% ± 6.5% and at the end of test 91.1% ± 6.5% (p<0.001). Desaturation was observed in 241 patients (53.3%). There were two different patterns of desaturation: SpO2 decrease at the beginning of the 6MWT with recovery before the test end (57 patients, 23.7% of the patients with desaturation) and SpO2 decrease maintained at the end of exercise. Rest SpO2 and lung function values were significantly higher in patients with the first desaturation pattern. SpO2 88% was observed in 148 patients; in 26 of these cases (17.6%) SpO2 88% levels were only detected during the 6MWT. Conclusion: Continuous SpO2 measuring is better than SpO2 measurement performed immediately after 6MWT in detecting exercise induced desaturation.

Novas alternativas de produção de ácidos graxos altamente insaturados n-3 (HUFA n-3) são procuradas mediante várias abordagens experimentais na área aquícola considerando que a oferta atual de óleos marinhos é limitada. Como os ácidos graxos das séries n-3 e n-6 são metabolizados mediante os mesmos processos enzimáticos, o aporte de ácidos graxos essenciais da dieta poderia influenciar nos níveis de alongamento e desaturação em função da disponibilidade relativa destes compostos. O objetivo deste trabalho foi determinar a influência de diferentes relações 18:3n3/18:2n6 (ALA/LA - ácido linolênico/ácido linoleico) de rações exclusivamente vegetais, sobre o metabolismo de ácidos graxos de juvenis de pacu (Piaractus mesopotamicus). Inicialmente 18 unidades experimentais (caixas com 16 peixes) foram alimentadas por 34 dias (C1) com uma dieta controle (tratamento T6) contendo óleo de tilápia como único ingrediente de origem animal. Posteriormente, foram formados aleatoriamente, 6 grupos com 3 unidades experimentais cada. Em uma segunda fase, durante 72 dias, 5 grupos receberam dietas, contendo óleo de linhaça e soja em substituição ao óleo de tilápia, com relações calculadas de ALA/LA de: 2,98 (T1); 1,68 (T2); 1,03 (T3); 0,61 (T4) e 0,35 (T5) e um grupo continuou com a dieta controle (T6). Nesta segunda fase, determinaram-se parâmetros de desempenho zootécnico e metabolismo de ácidos graxos em 3 intervalos de 24 dias (C2=58 dias, C3=82 dias e C4=106 dias). Os animais apresentaram crescimento e ganho de peso sem diferenças significativas entre os grupos e com aumento progressivo da proporção de gordura corporal total. A composição de ácidos graxos da dieta influenciou de forma proporcional sobre a composição da maioria de ácidos graxos de corpo inteiro. Os coeficientes de digestibilidade aparente aumentaram conforme o grau de instauração dos ácidos graxos e sua abundância relativa na dieta. A concentração de ácidos graxos polinsaturados nos lipídios de corpo inteiro não diferiu entre a maioria de tratamentos. O teor e aparecimento do ácido graxo 20:5n3 (EPA) e a atividade da enzima &Delta;-5 desaturase dos grupos T1, T2 e T3 foi menor que os demais tratamentos no período C4. O aparecimento de HUFA n-3 e n-6, atividade &Delta;-6 desaturase total e atividade &Delta;-6 desaturase sobre os ácidos graxos n-3 totais dos tratamentos T1 a T5 foram maiores que no T6 (controle). Estes resultados demonstram que o pacu (Piaractus mesopotamicus) é capaz de alongar e desaturar ácidos graxos essenciais para produzir ácidos graxos altamente insaturados (ácidos graxos com no mínimo 20 C e 3 ligações duplas - HUFA). Esta atividade é diminuída pela presença, mesmo em quantidades pequenas, de HUFA na dieta. Além disso, sugerem que relações ALA/LA da dieta, iguais ou maiores que 1, provocam diminuição na taxa de produção de 20:5n3, nos níveis testados neste estudo. / New alternatives for production of highly unsaturated fatty acids n-3 (n-3 HUFA) are sought by various experimental approaches in aquaculture, considering that the current supply of marine oils is limited. Since fatty acids of the n-3 and n-6 series are metabolized by the same enzyme processes, the supply of essential fatty acids of the diet could influence the elongation and desaturation levels, depending on the relative availability of these compounds. The objective of this study was to determine the influence of different 18:3n-3/18:2n-6 ratios (ALA/LA - linolenic acid/linoleic acid) of diets containing exclusively vegetable ingredients on the metabolism of fatty acids, of pacu juveniles (Piaractus mesopotamicus). Initially, 18 experimental units (boxes with 16 animals) were fed a control diet (T6 treatment) containing tilapia oil as the sole animal ingredient for 34 days (C1). Later, 6 groups with 3 experimental units each were formed at random. In a second phase, during 72 days, five groups were fed diets containing linseed and soy oils to replace tilapia oil, with calculated ALA/LA ratios: 2.98 (T1); 1.68 (T2); 1.03 (T3); 0.61 (T4) and 0.35 (T5) and a group continued with the control diet (T6). In the second phase were determined growth performance parameters and fatty acid metabolism in three intervals of 24 days (C2 = 58 days = 82 days and C3 C4 = 106 days). The animals showed growth and weight gain with no significant differences between groups and progressive increase in the proportion of total body fat. The fatty acid composition of the diet influenced proportionally on the composition of the majority of whole body fatty acids. The apparent digestibility increased as the degree of unsaturation of fatty acids and their relative abundance in the diet. The concentration of polyunsaturated fatty acids in whole body lipids did not differ among the most treatments. The content and appearance of the fatty acid 20:5n3 (EPA) and the activity of &Delta;-5 desaturase enzyme of groups T1, T2 and T3 was lower than the other treatments in C4 period. The appearance of n-3 and n-6 HUFA, &Delta; 6-desaturase activity and the total &Delta; 6-desaturase activity on the total n-3 fatty acids from T1 to T5 treatments were higher than T6 (control). These results demonstrate that pacu juveniles are able to elongate and desaturate essential fatty acids to produce highly unsaturated fatty acids. This activity diminishes by the presence of even small amounts of HUFAs in the diet. Moreover, it suggests that ALA/LA ratio of diet, equal to, or greater than one, cause a decrease in the rate of production of 20:5n3, within the levels tested in this study.

Submitted by Nadir Basilio (nadirsb@uninove.br) on 2018-07-17T21:01:40Z No. of bitstreams: 1 Cristiane Helga Yamane de Oliveira.pdf: 734503 bytes, checksum: b1eff73874a975c200780b9676f447b3 (MD5) / Made available in DSpace on 2018-07-17T21:01:40Z (GMT). No. of bitstreams: 1 Cristiane Helga Yamane de Oliveira.pdf: 734503 bytes, checksum: b1eff73874a975c200780b9676f447b3 (MD5) Previous issue date: 2016-12-13 / Introduction: Different modalities exercise lead to different magnitudes of pulse oxygen desaturation (DeSpO2) in lung diseases. Objective: To compare the exercise-induced DeSpO2 between incremental cardiopulmonary exercise test on a treadmill (TECPI-E) and the incremental shuttle walk test (ISWT) and between sub-maximum cardiopulmonary exercise test (TECPS-E) and endurance SWT (ESWT) in patients with bronchiectasis (BCT). Material and methods: 72 patients with BCT (28 men, 48 ± 15 years, FEV1:54 ± 23% of predicted) and not oxygen dependent were assessed. The order of the TECPI-E and SWTI was randomized, but not the TECPS-E and ESWT because they require that incremental tests be performed first. Treadmill and hallway tests were performed on two different visits. A reduction  4 was considered DeSpO2. Results: There was no difference in DeSpO2 between TECPI-E (-7.7% ± 6.3%) and ISWT (-6.3% ± 5.8%) and between TECPS-E (-6,8% ± 5,8%) and ESWT (-7.2% ± 6.3%). In the incremental and endurance tests, there was an agreement to DeSpO2 or not DeSpO2 in 56 and 55 patients, respectively. There was a statistically significant difference in heart rate (percentage of the maximum predicted) between TECPI-E (87.0% ± 9.0%) and ISWT (78.9% ± 11.4%) and between TECPS-E (84.5% ± 9.9%) and ESWT (79.3% ± 11.8%). However, when comparing patients who reached 85% of predicted maximum heart rate or not, there was no difference in the magnitude of DeSpO2. Conclusion: In patients with BCT, our results show that field-based tests may replace the laboratory-based tests when the clinic question is the evaluation of exercise-induced DeSpO2. / Introdução: Diferentes modalidades de exercício físico determinam diferentes magnitudes de dessaturação de pulso de oxigênio (DeSpO2) em pneumopatias. Objetivo: Comparar a DeSpO2 induzida pelo exercício entre teste de exercício cardiopulmonar (TECP) incremental em esteira (TECPI-E) e o shuttle walk test (SWT) incremental (SWTI) e entre TECP submáximo em esteira (TECPS-E) e SWT endurance (SWTE) em pacientes com bronquiectasia (BCQ). Material e métodos: Foram avaliados 72 pacientes com BCQ (28 homens, 48  15 anos, VEF1: 54 ± 23 % previsto), não dependentes de oxigênio. A ordem de realização do TECPI-E e SWTI foi randomizada, mas não o TECPS-E e SWTE, pois esses necessitam dos testes anteriores. Os testes em esteira e em corredor foram realizados em duas visitas diferentes. Uma redução  4 foi considerada DeSpO2. Resultados: Não houve diferença na DeSpO2 entre TECPI-E (-7,7% ± 6,3%) e SWTI (-6,3% ± 5,8%) e entre TECPS-E (-6,8% ± 5,8%) e SWTE (-7,2% ± 6,3%). Nos testes incrementais e de endurance, houve concordância de DeSpO2 ou não DeSpO2 em 56 e 55 pacientes, respectivamente. Houve diferença significante na frequência cardíaca (FC, % da máxima prevista) entre TECPI-E (87,0% ± 9,0%) e SWTI (78,9% ± 11,4%) e entre TECPS-E (84,5% ± 9,9% previsto) e SWTE (79,3% ± 11,8% previsto). No entanto, ao comparar os pacientes que atingiram ou não 85% da FC máxima prevista, não houve diferença na magnitude de DeSpO2. Conclusão: Nossos resultados demonstram que, em pacientes com BCQ, os testes de campo podem substituir os testes de laboratório quando a questão clínica é a avaliação da DeSpO2 induzida pelo exercício.

With a higher power rating and broader application, Gallium nitride (GaN) is a promising next-generation power switch. The current four GaN HEMTs in paralleled phase leg that can block 400 V and conduct 200 A current is very beneficial, thus making the protection method on a GaN phase leg an urgent topic. This thesis starts with an overview of shortcircuit robustness among silicon (Si), silicon carbide (SiC) and GaN devices. An approximately safe operation area (SOA) for a GaN power switch will also be determined. The various common shortcircuit protection methods are mentioned. Additionally, current research on a GaN semiconductor is summarized. Among all of the protection methods, desaturation detection is selected and analyzed through simulation and then implemented in a parallel enhancement-mode high-electron-mobility transistor (E-HEMT) GaN phase leg. With this desaturation detection feature, the GaN E-HEMT can be turned off as quickly as 200 ns, and in the worst case, 500 ns, during a shortcircuit test. The phase leg survived a series of shortcircuit tests with shortcircuit protection. For the proposed protection scheme, the best-case reaction time (200 ns) is similar to others in the literature, while the shortcircuit peak current and peak energy are higher. The worst-case performance of this design is limited by both the gate driver and the device shortcircuit robustness. Due to the fast switching speed of the GaN HEMT, the false turn-on phenomenon caused by the Miller effect can be a problem. A shoot through may occur with one switch false turn on. The Miller clamp is added to the phase leg to improve its reliability. After the hardware was implemented, the Miller clamp was tested and verified through a double pulse test (DPT). Compared to the phase leg without the Miller clamp, the gate is better protected from gate voltage overshoot and undershoot. The switching loss is reduced by 20 percent by using a new gate driver IC with higher current driving capability. The degradation effect of GaN power switches in different shortcircuit pulses was also studied. The device passes through the shortcircuit tests, but any degradation effect that may change its parameters and influence its normal operation characteristic need to be addressed. Several GaN devices were selected and characterized after several shortcircuit tests to observe any degradation effect caused by the shortcircuit. The degradation test results reveal a "recovery effect" of the GaN HEMT used in this project. The parameter variations on threshold voltage and on-resistance recover to the original state, several hours after the shortcircuit test. The test results match with the conclusion drawn in degradation test conducts by other research groups that the parameter variation during shortcircuit test is negligible. Also, repetitively fast shortcircuit tests on the GaN HEMT show that the shortcircuit protection limit for this device under 400 V bus should be limited to 300 ns. / Master of Science

Nowadays, major public concern is concentrated on reducing the usage of fossil fuels and reducing emissions of CO₂ by different energy advancement. Electric vehicle technology presents extremely effective way of reducing carbon emissions and paves the way of having sustainable and renewable energy future. In order to wear the cost of electric vehicles down, batteries have to be improved as well as higher power density and high reliability has to be achieved. This research work mainly focuses on achieving higher power density and higher reliability of the inverter stage by utilizing wide-bandgap SiC MOSFET semiconductor devices in electric vehicle application. In order to achieve higher reliability of the inverter stage, high bandwidth, high performance Rogowski coil switch current sensors are employed. These sensor were embedded on the PCB and integrated on the gate driver. High bandwidth switch current sensor measurement is used for fast short-circuit detection and protection of the SiC MOSFET semiconductor switches. Furthermore, comparison with conventional detection and protection method used in automotive IGBT applications is shown where novel protection showed superior performance. This thesis also shows principle of how to obtain phase currents of the system using Rogowski coil switch current sensor measurements. Digital reconstruction principle is employed to obtain the phase currents. Accurate and linear current sensor is achieved. By successfully realizing this integrated phase current measurement on the gate driver, elimination of the commercial current sensors from the system is possible. By eliminating existing phase current sensors, higher power density could be achieved. Sensor is evaluated in both continuous and discontinuous PWM schemes. / Master of Science / Together with renewable sources, electric vehicle will play an important role as a part of sustainable and renewable energy future by significantly reducing emissions of CO₂ into the atmosphere. In order to make electric cars more acceptable and accessible and make a significant impact on the environment, cost must be lowered down. To wear the cost of the electric vehicles down, powertrain of the car must be significantly improved and made smaller as well as lighter. This thesis mainly focuses on improving the reliability of the motor driving stage by implementing novel protection during fault periods such as short-circuit event. Furthermore, this novel protection allows current sensing that is crucial for motor control during normal operation periods. This will enable more compact motor driving stage since existing current sensing elements can be eliminated.