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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Interferência da apneia obstrutiva do sono e dessaturação noturna de oxigênio no agravamento clínico de pacientes com doença pulmonar obstrutiva crônica / Interference of obstructive sleep apnea and nocturnal oxygen desaturation in the clinical aggravation of patients with chronic obstructive pulmonary disease

Vera Lucia Toscano Stocco 24 November 2015 (has links)
Ao considerar que os distúrbios respiratórios relacionados ao sono, apneia obstrutiva do sono (AOS) e dessaturação noturna de oxigênio (DNO), podem estar presentes em pacientes com doença pulmonar obstrutiva crônica (DPOC), este estudo teve como objetivos: (1) estimar a frequência de AOS e DNO na amostra e nos graus e categorias GOLD (Global Initiative for Chronic Obstructive Lung Disease); (2) avaliar a relação da presença de AOS e DNO no agravamento clínico de pacientes com DPOC. Estudo transversal em 56 pacientes com DPOC estável e pressão parcial arterial de oxigênio (PaO2) diurna > 60 mmHg, submetidos à coleta dos seguintes dados: demográficos, antropométricos e de hábito tabágico; relato de ronco e sonolência diurna; número de exacerbações e hospitalizações; escala de dispneia do Medical Reserch Council modificada; teste de avaliação da DPOC; escala de sonolência de Epworth; espirometria; gasometria arterial; hemograma; monitorização ambulatorial da pressão arterial e polissonografia. Os pacientes foram classificados em graus e categorias GOLD e divididos em 3 grupos de estudo: grupo DPOC pura, grupo síndrome de sobreposição (SS) e grupo dessaturador (D). Os resultados mostraram: 30 pacientes do sexo masculino (54%); idade: 63,7 (DP=7,3) anos; índice de massa corpórea (IMC): 25,2 (DP=4,3) Kg/m2; circunferência do pescoço: 38,4 (DP=3,2) cm; 46% tabagistas; carga tabágica: 50,0 (DP=20,7) anosmaço; volume expiratório forçado no primeiro segundo (VEF1): 56,4 (DP=19,8) % do previsto; PaO2: 78,3 (DP=8,0) mmHg; saturação arterial de oxigênio (SaO2): 95,5 (DP=1,4) %; 29 pacientes (52%) eram do grupo DPOC pura, 14 (25%) do grupo SS e 13 (23%) do grupo D; frequência de AOS e DNO na amostra: 25% e 23%, respectivamente; frequência de AOS nos GOLD 1234: 14%, 24%, 25%, 50% (p=0,34) e GOLD ABCD: 44%, 15%, 25%, 26% (p=0,31), respectivamente; frequência da DNO nos GOLD 1234: 29%, 24%, 19%, 25% (p=0,88) e GOLD ABCD: 11%, 20%, 25%, 30% (p=0,35), respectivamente. Evidências de diferença estatística entre os 3 grupos: sexo (DPOC pura: 48% de homens versus SS: 86% versus D: 31%; p<0,01); IMC (DPOC pura: 23,9 (DP=3,8) versus SS: 24,7 (DP=4,6) versus D: 28,6 (DP=3,5) Kg/m2; p<0,01); circunferência do pescoço (DPOC pura: 37,4 (DP=2,7) versus SS: 40,0 (DP=2,9) versus D: 38,9 (DP=3,9) cm; p=0,03); relato de sonolência diurna (DPOC pura: 17% versus SS: 0 versus D: 38%; p=0,03); SaO2 diurna (DPOC pura: 95,8 (DP=1,5) % versus SS: 95,8 (DP=1,1) % versus D: 94,7 (DP=1,3) %; p=0,04); descenso noturno diastólico (DPOC pura: 6,5 (DP=7,0) % versus SS: 2,3 (DP=7,3) % versus D: 5,6 (DP=7,0) %; p=0,04). Conclui-se que, em pacientes com DPOC, a frequência de AOS e DNO foi elevada na amostra e não sofreu influência dos graus ou categorias GOLD; encontrou-se associação entre a presença de AOS e o sexo masculino, maior circunferência do pescoço e menor descenso noturno diastólico; e a presença de DNO associou-se com o sexo feminino, maior IMC, maior relato de sonolência diurna e menor SaO2 diurna. Estas características podem contribuir para diferenciar clinicamente os grupos SS e D do grupo DPOC pura / While considering that the sleep-related breathing disorders, obstructive sleep apnea (OSA) and nocturnal oxygen desaturation (NOD) may be present in patients with chronic obstructive pulmonary disease (COPD), this study aimed to: (1) to estimate the frequency of OSA and NOD in the sample and in the GOLD degrees and categories (Global Initiative for Chronic Obstructive Lung Disease); (2) to assess the relationship of the presence of OSA and NOD in the clinical aggravation of patients with COPD. Transversal study in 56 patients suffering from stable COPD and daytime partial arterial oxygen tension (PaO2) > 60 mmHg, subjected to the collection of the following data: demographic and anthropometric data, and smoking habit; report of snoring and daytime sleepiness; number of exacerbations and hospitalizations; modified Medical Research Council dyspnea scale; COPD assessment test; Epworth Sleepiness Scale; spirometry; arterial gasometry; hemogram; ambulatory blood pressure monitoring and polysomnography. The patients were classified in GOLD degrees and categories and divided into 3 study groups: pure COPD group, overlap syndrome (OS) and desaturator group (D). The results showed: 30 male patients (54%); age 63,7 years old (DP=7,3); body mass index (BMI) 25,2 Kg/m2 (DP=4,3); neck circumference 38,4 cm (DP=3,2); 46% smokers; smoking load 50,0 pack years (DP=20,7); forced expiratory volume in the first second (FEV1) 56,4% of the expected (DP=19,8); PaO2 78,3 mmHg (DP=8,0); arterial oxygen saturation (SaO2) 95,5% (DP=1,4); 29 patients (52%) belonged to the pure COPD group, 14 (25%) to the OS group and 13 (23%) to the D group; frequency of OSA and NOD in the sample: 25% and 23%, respectively; frequency of OSA in the GOLD 1234: 14%, 24%, 25%, 50% (p=0,34) and GOLD ABCD: 44%, 15%, 25%, 26% (p=0,31), respectively; NOD frequency in the GOLD 1234: 29%, 24%, 19%, 25% (p=0,88) and GOLD ABCD: 11%, 20%, 25%, 30% (p=0,35), respectively. Evidences of statistical difference among the three groups: sex (pure COPD: 48% men versus OS: 86% versus D: 31%; p<0,01); BMI (pure COPD: 23,9 (DP=3,8) versus OS: 24,7 (DP=4,6) versus D: 28,6 (DP=3,5) Kg/m2; p<0,01); neck circumference (pure COPD: 37,4 (DP=2,7) versus OS: 40,0 (DP=2,9) versus D: 38,9 (DP=3,9) cm; p=0,03); report of daytime sleepiness (pure COPD: 17% versus OS: 0 versus D: 38%; p=0,03); daytime SaO2 (pure COPD: 95,8% (DP=1,5) versus OS: 95,8% (DP=1,1) versus D: 94,7% (DP=1,3); p=0,04); diastolic sleep dip (pure COPD: 6,5% (DP=7,0) versus OS: 2,3% (DP=7,3) versus D: 5,6% (DP=7,0); p=0,04). It was concluded that, in patients with COPD, the OSA and NOD frequency was high in the sample and was not influenced by GOLD grades or categories. An association between the presence of OSA and the male sex, a larger neck circumference and a smaller diastolic sleep dip was found; and the presence of the NOD was associated with the female sex, a larger BMI, a more significant report of daytime sleepiness and a smaller daytime SaO2. These characteristics may contribute to differentiate clinically the OS and D groups from the pure COPD group
32

Numerical Investigation for Slope Stability of Expansive Soils and Large Strain Consolidation of Soft Soils

Qi, Shunchao January 2017 (has links)
Several geotechnical processes can only be reliably interpreted by taking account of the soil-atmosphere interactions. This thesis investigates two geotechnical problems involving soil-atmosphere interactions that drive water flow through the soil skeleton in two opposite directions; Problem 1: slope failure in expansive soils induced by water infiltration, Problem 2: large strain consolidation of soft soils induced by water evaporation. Both problems are of practical interest for safe and economical design of various geotechnical infrastructures. Two major geotechnical activities in the world; namely, the construction of water transfer canal in expansive soil area in China and the deposition of oil sands and hard rock tailings in Canada can be cited as classic examples of Problems 1 and 2, respectively. In such problems, substantial zones of the domain may switch between an unsaturated and saturated condition. Therefore, rational analysis requires simultaneous modelling of both unsaturated and saturated soil behaviour. The first goal of this thesis is to investigate the influence of swelling (the most characteristic behaviour of expansive soils) on slope stability using numerical methods. Swelling of expansive soils contributes to slope instability during rainfall because of two key reasons (i) soil swelling affects the flow process that actually induces swelling, (i.e. a typical coupling phenomenon), and (ii) swelling-induced stress redistribution and displacement development. In this thesis, the first effect is studied by a coupled (mechanical-hydraulic) numerical analysis of the response of a slope to rainfall using commercial software (GeoSlope). The second effect, the swelling-induced stress redistribution and displacement development after wetting, is tracked using a newly developed numerical program. In the program strain softening behaviour is introduced into the elasto-plastic Mohr-Coulomb Model for modelling unsaturated soil. A novel stress (net stress and suction)-dependent model for moduli of elasticity, combined with the predictive model for shear strength based on Soil Water Retention Behaviour are incorporated into the numerical program to achieve a smooth transition between saturated and unsaturated states. The results show that soil swelling can decrease the factor of safety by accelerating the wetting front depth due to hydro-mechanical coupling, while changes of sliding mass geometry has a negligible influence. The change of stress regime associated with soil swelling is significant to induce plastic strain softening (swelling-induced softening) and contribute to the slope failures. The second goal of thesis is to develop a novel computer program for simulation of large strain consolidation of soft soil under both self-weight and evaporation conditions. This program is both theoretically sound and practically applicable. Several basic/advanced constitutive models for unsaturated soils, including State Surface Model (SSM), Barcelona Basic model (BBM), Glasgow Coupled model (GCM) and bounding surface water retention model, are innovatively implemented into a piece-wise linear framework solved using finite difference technique. The developed program is referred to as UNSATCON-(ML), which has been tested using (a) existing analytical/numerical solutions and (b) various laboratory and field studies for single-layer and multiple-layer deposition of hard rock and oil sands tailings. Features of UNSATCON-(ML) that are improvements over existing models typically used to analyze consolidation-desiccation in soft soils include: (i) coupling of soil large deformation with true unsaturated water flow; (ii) correct reproduction of the shrinkage behaviour of soil under evaporation-induced desiccation; (iii) smooth transition between saturated and unsaturated states despite that some selected models are established using two independent stress variables, (iv) ensuring strictly mass conservation of water, and (v) simulation of irrecoverable volume change and hydraulic hysteresis to properly analyze multilayer tailings deposition. A number of hypothetical field case analyses are carried out using UNSATCON-ML, illustrating its applicability to industry.
33

Teoretický přístup k selektivní aktivaci vazeb C-H / Selective Activation of C-H Bonds from Theoretical Perspective

Bím, Daniel January 2019 (has links)
The transfer of a hydrogen atom is a crucial step in a wide variety of chemical and biological processes and modus operandi of many metalloenzymes. While several factors that govern the reactivity and selectivity were already clarified in the past century, a growing body of experimental and theoretical studies also revealed numerous gaps in our unified understanding. As a consequence, the direct functionalization of non-activated C-H bonds by synthetic catalysts is still very limited. In the thesis, the hydrogen-atom-abstraction (HAA) reactions are broken down into the elementary proton- and electron-transfer steps and the reactivity/selectivity of oxidants is analyzed with respect to their physico-chemical properties, acidity constants and reduction potentials. First, a quantum chemical (QM)-based computational protocol for calculation of reduction potentials of iron complexes is introduced and validated over a large series of experimental data, including a set of challenging mononuclear FeIV O species that provide direct connection to biomimetic non-heme iron catalysis. Next, the methodology is extended to deal with reduction potentials of transition-metal complexes possessing higher total molecular charges, experimentally measured in polar solvents. In such cases, the accurate description of solvation...
34

Peripheral Circuits Study for High Temperature Inverters Using SiC MOSFETs

Qi, Feng 12 September 2016 (has links)
No description available.
35

Comparação de diferentes testes funcionais e suas relações com estado funcional e qualidade de vida em indivíduos com doença pulmonar obstrutiva crônica (DPOC)

Pessoa, Bruna Varanda 29 February 2008 (has links)
Made available in DSpace on 2016-06-02T20:19:07Z (GMT). No. of bitstreams: 1 1715.pdf: 1720127 bytes, checksum: fc1c815a998967a82188d3aba2a3cb89 (MD5) Previous issue date: 2008-02-29 / Financiadora de Estudos e Projetos / Objectives: to evaluate and compare the responses to the various functional tests, and the concordance between the six-minute walk test in hallway (6MWT) and the of oval track (6MWToT), of treadmill (6MWTT), and of treadmill with inclination (6MWTTI), the six-minute step test (6MST) and the two-minute chair test (2MCT), in patients with Chronic Obstructive Pulmonary Disease (COPD), and to correlate the responses with functional state and quality of life. Methods: Ten patients with COPD (72±7years, 30%<FEV1<80%predicted) were assessed using the functional tests. A dyspnea was assessed using the London Chest Activity of Daily Living and the Medical Research Council scales; and the quality of life was assessed using the St George s Respiratory Questionnaire (SGRQ). Results: In the interests analysis, there was lower walking distance in the 6MWTT and 6MWTTI was observed, to compare in the 6MWT and 6MWToT; the &#8710;Sp,O2 (delta of arterial oxygen saturation measured by pulse oximeter) in the 6MWTTI was significantly greater that in the 6MWT, but not between to change in dyspnea and fatigue/pain in the lower-limbs between rest and exercise of peak (&#8710;). Concordance and correlation was observed between the lower Sp,O2 of the 6MWT with the 6MWToT, 6MWTT, 6MWTTI, 6MST and 2MCT. Strong correlations was observed between the performances on the 6MST and 6MWT, 6MWToT and 6MWTT; and between the physical activity domain of the SGRQ with the performances in the 6MWT, 6MWToT, 6MWTT, 6MST and 2MCT. Conclusion: The functional tests produced similar subjective responses; however, the 6MWTTI caused greater desaturation that 6MWT. The concordance between the 6MWT and the tests performed, suggests acceptable use of any these tests in the physiotherapeutic clinical routine of the individuals COPD. The tests performed, except the 6MWTTI, shown to be indicators of the quality of life (physical activity domain) / Objetivos: avaliar e comparar, em indivíduos com doença pulmonar obstrutiva crônica (DPOC), as respostas aos vários testes funcionais, e a concordância entre o teste de caminhada de seis minutos em corredor (TC6 ) e o de pista oval (TC6Po), de esteira (TC6E), de esteira com inclinação (TC6E-Incl), do degrau de seis minutos (TD6 ) e da cadeira de dois minutos (TCad-2min). Correlacionar essas respostas com estado funcional e qualidade de vida. Métodos: Foram avaliados 10 indivíduos com DPOC (72±7anos, 30%<VEF1<80%previsto) através dos testes; escalas London Chest Activity of Daily Living e Medical Research Council e St George s Respiratory Questionnaire (SGRQ). Resultados: Na análise inter-testes, observou-se menor distância percorrida no TC6E e TC6E-Incl comparado ao TC6 e TC6Po; o &#8710;SpO2 (delta da saturação periférica de oxigênio) no TC6E-Incl foi significantemente maior que no TC6 , mas não entre os deltas da dispnéia e cansaço/dor nas pernas. Observou-se concordância e correlação entre a menor SpO2 do TC6 com o TC6Po, TC6E, TC6E-Incl, TD6 e TCad-2min. Encontraramse fortes correlações entre os desempenhos no TD6 e TC6 , TC6Po e TC6E; e entre SGRQ domínio atividade física com os desempenhos nos TC6 , TC6Po, TC6E, TD6 e TCad-2min. Conclusão: Os testes funcionais produziram respostas subjetivas similares; entretanto, o TC6E-Incl ocasionou maior dessaturação que o TC6 . A concordância entre o TC6 e os testes realizados, sugere aceitável utilização de qualquer um desses testes na rotina clínica fisioterapêutica dos indivíduos com DPOC. Os testes realizados, exceto o TC6E-Incl, mostraram ser indicadores da qualidade de vida (domínio atividade física)
36

Étude multi-échelles des courbes de désaturation capillaire par tomographie RX / Multi-scales investigation of capillary desaturation curves using X-ray tomography.

Oughanem, Rezki 20 December 2013 (has links)
L'injection de tensioactifs est une méthode très appliquée dans le domaine de la récupération améliorée des hydrocarbures. Cependant, son efficacité repose sur la capacité de ces agents chimiques à mobiliser l'huile résiduelle en diminuant la tension interfaciale entre l'huile et l'eau. Des modèles à l'échelle du réservoir calculent l'efficacité de la récupération d'huile résiduelle par injection de solutions contenant des tensioactifs. Les mécanismes physiques pris en compte dans les modélisations font intervenir la physico-chimie du système roche-fluide et une courbe globale donnant la saturation résiduelle en huile en fonction du nombre capillaire (courbe de désaturation capillaire). Cette donnée est majeure dans le calcul de l'efficacité de récupération d'huile par injection de solutions de tensioactifs. En effet la mobilisation de l'huile résiduelle laissée en place après injection d'eau n'est possible qu'en augmentant considérablement le nombre capillaire. La prédiction de l'efficacité d'un procédé chimique de récupération passe par la compréhension, à l'échelle du pore, du processus de mobilisation des ganglions d'huile suivant la structure poreuse et le nombre capillaire. L'objet de cette thèse est de caractériser la récupération d'huile tertiaire en fonction du nombre capillaire dans diverses roches mouillables à l'eau. Ces courbes permettront de quantifier l'effet de la microstructure, les hétérogénéités du milieu poreux et diverses propriétés pétrophysiques sur la récupération d'huile. Cette thèse permettra aussi de caractériser les différents mécanismes d'action de tensioactifs sur la mobilisation d'huile résiduelle dans le milieu poreux. L'expérimentation par tomographie RX est utilisée. La tomographie RX permettra de caractériser les courbes de désaturation capillaire à l'échelle de Darcy et visualiser localement le déplacement d'huile résiduelle à travers les milieux poreux. Des essais d'écoulement diphasique sous micro-CT permettront d'observer in-situ et d'étudier les interfaces eau/huile et leurs évolutions en 3D au sein du milieu poreux en fonction du nombre capillaire. / Oil recovery by surfactant injection is related to oil-water interfacial tension and rock properties through the capillary number. In the modeling of oil recovery by surfactant injection, fluid flow physical mechanisms are represented through the capillary desaturation curve (CDC). This curve is central in the evaluation of oil recovery efficiency. In order to mobilize residual oil trapped after waterflooding by capillary forces, chemical EOR rely on increasing capillary number to extremely high values. The mechanisms governing oil release can be described at the pore scale where the balance of capillary and viscous forces is achieved. This description will help to predict the efficiency of surfactant based EOR processes by taking into account the porous geometry and topology, the physico-chemical properties of the fluids and the different phase interaction. The objective of this work is to characterize capillary desaturation curves for various strongly water-wet sandstones. These curves will be used to study the relationship between tertiary oil recovery and the pore structure, porous media heterogeneity and petrophysicals properties. The other aim of this work is to map the different mechanisms of oil recovery by surfactant injection. Experiments under X-Ray tomography are proposed. X-Ray tomography will be applied to characterize capillary desaturation curve at Darcy scale and to visualise the two phase flow saturation after injection. Pore scale experiments based on X-Ray micro-tomography imaging are performed to describe the different mechanisms of oil mobilization.

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