Please read the abstract in the section 05summary, of this document / Dissertation (MSc (Biochemistry))--University of Pretoria, 2007. / Biochemistry / unrestricted

The current Coronavirus disease 2019 (COVID-19) outbreak, caused by a virus called severe acute respiratory syndrome 2 (SARS-CoV-2), has become a global health emergency. Recent findings in case studies assert that the transmigration of SARS-CoV-2 to the nervous system implicates severe neurotropic pathologies, including the onset of the rare autoimmune disease called Guillain-Barré syndrome (GBS). GBS is recognized as several disorders characterized by immune-mediated polyradiculoneuropathy, which is typically preceded by an infection or other immune stimulation. The symptoms of GBS initially present as acute symmetrical ascending paresthesia, weakness, and paralysis. This meta-analysis serves to help understand the predisposing factors (such as gender, age, comorbidities) and the clinical features of COVID-19- induced GBS. Most patients affected were 40 years or older and comprised 78.2% of all the cases. Males comprised most of the cases (62.8%; n=76). The patient mortality was 9.1%, intensive care unit (ICU) admission was 46.6%, and the need for mechanical ventilation was 35.8%. It was found that concomitant GBS and COVID-19 patients most often presented with increased cerebral spinal fluid (CSF) protein levels (88%; n=106), hyporeflexia or areflexia (87.6%) (n=106), lower limb strength and sensation impairment (91.7%; n=111), upper limb strength and sensation impairment (83.5; n=101), and somatic sensation impairment (73.6%; n=89). It is postulated that COVID-19 triggers the onset of GBS through a “cytokine release storm” (CRS) that occurs in the early stages of the disease. The same cytokines and chemokines involved in this CRS caused by COVID-19 contribute to the onset of GBS. Predisposing factors which influence this concomitance include male gender and older age. Most of the reported symptoms included abnormal limb functions (including paresthesia, weakness, and paralysis) and absent or weak deep tendon reflexes. The most common variant of GBS observed was AIDP, and the most significant laboratory finding among patients was high CSF protein levels.

Les Barres d’Hopkinson sont couramment utilisées pour tester les matériaux à des hauts taux de déformations. Souvent, différents systèmes de barres sont utilisés pour tester les matériaux en tension ou en compression. Par contre, il serait pratique d’utiliser un seul système, pour prendre des mesures en tension et en compression. Des études ont été faites pour convertir le système de compression existant du centre de Recherche et Développement pour la Défense Canada (RDDC) de ValCartier. Un concept a été choisi parmi 6 systèmes de tension déjà existants. Le choix a été validé avec un modèle d’éléments finis fait sur LS-Dyna. Le modèle a été calibré sur des résultats de compression fournis par le RDDC. Il fut ensuite modifié pour intégrer le nouveau concept. À cause d’un manque de ressources, les résultats de simulation sur LS-Dyna n’ont pu être comparés avec des résultats expérimentaux, puisqu’un premier prototype n’a pu être fabriqué. / The Split Hopkinson Pressure Bars (SHPB) is a common method used to characterize materials at high rates of strain. First used to experiment on materials in compression, the method was adapted to do tests in tension and torsion. The compression apparatus consists of a specimen sandwiched between 2 pressure bars, called the input bar and the output bar. A third bar, the striker, is launched at the input bar. Upon impact, a compressive pulse traveling toward the specimen is generated. This load is partially transmitted into the specimen and the output bar, the rest of it being reflected back into the input bar. Using measurements of the input, transmitted and reflected pulse, it is possible to develop the stress-strain response of the material deforming at high strain rates. This is achieved using strain gages adequately placed on both pressure bars. Many researchers use a different SHPB system when it comes to tension tests. Many methods exist, but all of them are based on compressive experiments. It would therefore be convenient to only have one system, which is capable of taking measurements both in compression and tension. Based on the compressive SHPB apparatus used by the Defense, Research and Development Canada (DRDC) center in ValCartier, studies were made to convert the compressive system into a tensile setup. The goal was to modify it with minimum changes possible, in order to easily go back and forth between the two configurations. A design choice was made, considering 6 existing tension systems. To validate the decision, a finite element model was created using LS-Dyna. The modal was first aligned with the compression results provided and then modified to implement the selected design. Because of a lack of available resources, LS-Dyna simulation results were not compared with experimental data, as it was not possible to create a first prototype.

Si de nombreuses études ont été consacrées à l'analyse des grands tours préparatoires aux sorties, aux sorties elles-mêmes et aux lâchers de barre en barre fixe ou barre supérieure de barres asymétriques, les éléments avec envol pour passer d'une barre à l'autre aux barres asymétriques (lâcher la barre inférieure pour saisir la barre supérieure ou l'inverse) n'ont, à notre connaissance, pas fait l'objet de telles études. Cette thèse de doctorat présente dans sa première partie une analyse cinématique du " pieds barre temps de ventre " ainsi qu'une analyse des moments cinétique et d'inertie mis en jeu par deux groupes de gymnastes, des expertes et des novices, lors de la réalisation de ce mouvement. La deuxième partie met en évidence des lois de contrôle moteur utilisées par les deux groupes pour réaliser l'élément. Afin de déterminer si les mouvements des deux groupes sont susceptibles d'améliorations et si la trajectoire créée au lâcher de la barre inférieure ou la gestuelle mise en jeu influence davantage la performance, une optimisation du pieds barre temps de ventre est proposée dans la troisième partie. Enfin, l'effet de l'introduction d'une loi de contrôle moteur dans le processus d'optimisation sur le réalisme des mouvements optimisés est envisagé.

Le travail présenté dans cette thèse propose des nouvelles méthodes de diagnostic des défauts dans les machines à courant alternatif. Les procédures de diagnostic décrites sont fiables, originales, peu coûteuses et simples à mettre en œuvre. Elles présentent l’avantage d’être non invasives et viennent éliminer le principal inconvénient présenté par les autres méthodes de diagnostic déjà connues qui ont recours à la comparaison avec un état supposé sain et connu. L’analyse porte principalement sur le champ magnétique de dispersion, plus particulièrement ses composantes axiales et radiales qui présentent des sensibilités différentes aux défauts. À cet effet, les phénomènes dus aux défauts de court-circuit entre spires dans le bobinage statorique, l’excentricité et la rupture de barres rotoriques, sont étudiés. Il est abordé en particulier les effets de ces défauts dans le cas de la machine asynchrone et celui de la machine synchrone sur le champ axial et sur le champ radial. Pour chaque défaut, des signatures spécifiques sont mises en évidence et expliquées par la modélisation analytique et la modélisation numérique qui comprend les méthodes par circuits électriques couplés et méthodes par éléments finis. Des défauts ont été créés au rotor et au stator sur différentes machines, afin de valider expérimentalement les méthodes de diagnostic proposées. / The work described in this thesis proposes new procedures to diagnose faults in AC machines. The diagnostic procedures described are reliable, original, inexpensive and simple to implement. They have the advantage of being noninvasive and just get rid from the main drawback presented by other diagnostic methods based on a comparison with a healthy state assumed to be known. The analysis focuses on the magnetic field dispersion in the vicinity of the machine, especially its radial an axial distribution which presents different sensitivity according to various faults. To this end, the phenomena due to inter-turn short-circuit faults in the stator winding, rotor eccentricity and broken rotor bars, are studied in the case of an induction machine and a synchronous machine. For each fault, specific signatures are identified and justified by analytical modeling and numerical method of analysis including coupled electric circuit and finite element methods. Defects have been created in the rotor and stator on different machines in order to validate experimentally the suggested diagnostic procedures.

Objetivo: Comparar as relações de custo-efetividade de duas terapias, Imunoglubulina Intravenosa (IgIV) e Plasmaferese (PE), no tratamento da Síndrome de Guillain-Barré sob a perspectiva do sistema público (SUS). O objetivo secundário foi avaliar a adesão às recomendações da Comissão de Medicamentos do HCPA Métodos: estudo transversal com análise econômica de pacientes tratados por Síndrome de Guillain-Barré no período de junho de 2003 a junho de 2008 no Hospital de Clínicas de Porto Alegre (HCPA). Foi realizada análise de custo-efetividade do emprego de IgIV e de PE nestes pacientes, pelo método de minimização de custos, considerando-se somente os custos diretos sanitários, fornecidos pelo sistema gerencial da instituição . Foram excluídos os pacientes que usaram outro tipo de tratamento associado ou isolado. Coletaram-se os dados através da revisão dos prontuários. A gravidade da doença na internação foi classificada como: doença leve, quando caminhar foi possível; doença moderada, quando caminhar foi impossível; doença grave, quando os pacientes necessitaram de ventilação assistida. A incapacidade na alta foi estabelecida pela escala de sete pontos de Hughes. A adesão às recomendações da Comissão de Medicamentos do HCPA, objetivo secundário, foi avaliada através da dose e o esquema de prescrição da IgIV. Resultados: Vinte e cinco participantes (2 a 70 anos) foram incluídos no estudo, cinco tratados com PE, empregando-se Albumina Humana como substituto do plasma, e 20 tratados com IgIV. O custo total do tratamento de um paciente com PE foi R$10.603,88 (± 2.978,12) e o de um que recebeu IgIV foi R$ 32.103,00 (± 21.454,24). O custo total da internação foi de R$45.027,14 (± 32.750,45) para os tratados com PE e de R$ 60.844,28 (±48.590,52) para os que receberam IgIV. Em relação ao desfecho clínico principal, melhora na escala de incapacidade de sete pontos, após o tratamento com uma das alternativas escolhida, a mediana dos pacientes que internaram com grau de gravidade 3 e que foram tratados com PE foi igual a dos que receberam IgIV. Em relação à permanência hospitalar, permanência em UTI e dias de Ventilação Mecânica, não houve diferença estatisticamente significativa entre os dois tratamentos. Conclusões: Quando comparados os custos médios das duas opções terapêuticas, uma delas aparece claramente com menor custo. Quando comparados os desfechos, após o emprego de cada opção terapêutica, estes não revelam diferença. Concluímos que, no HCPA, a opção pelo procedimento Plasmaferese é mais custo efetiva do que o emprego da IgIV. / Objectives: To compare the cost-effectiveness of two distinct therapies, Intravenous Immunoglobulin (IVIg) and Plasma Exchange (PE) in the treatment of Guillain-Barré Syndrome, concerning the public health care system. Compliance to the guidelines of the Pharmacy and Therapeutics Committee of the Hospital de Clínicas de Porto Alegre was a secondary objective. Methods: A cross-sectional, economical analysis was conducted, including patients treated for GBS in the period from June, 2003 through June, 2008 in Hospital de Clínicas de Porto Alegre (HCPA). The cost-effectiveness of the use of IVIg and PE in such patients was studied through the cost minimization method, considering direct medical costs only (2008 currency), yield by the management of the institution. Patients receiving treatments other than PE or IVIg were excluded. Data were collected by chart reviews. Severity of disease on admittance was classified as follows: mild disease, when the patient was able to walk; moderate disease, when the patient was unable to walk, and severe disease, when assisted ventilation was required. Disability on discharge was established by the 7-point scale of Hughes. Compliance to the guidelines of the Pharmacy and Therapeutics Committee was evaluated through the dose and prescription scheme of IVIg. Results: Twenty-five participants (2 to 70 years of age) were included in the study, 5 were submitted to treatment with PE, using human albumin as replacement for plasma, and 20 were treated with IVIg. The total treatment cost for PE in a single patient was US$6,058.85 (±1,701.78 SD), and the same expense for IVIg was US$18,344.57 (± 12,259.56 SD) (p = 0.035). Total inpatient cost was US$25,729.79 (± 18,714.54 SD) in the PE group, and US$34,768.16 (±27,766.01 SD) (p=0.530) in the IVIg group. The main clinical outcome was improvement in the 7-point disability grade scale. The median of that measure in patients admitted with a severity grade 3 treated either with PE and IVIg was the same. Secondary outcomes, such as in-hospital stay, ICU stay, and number of days on mechanical ventilation revealed no statistically significant difference between treatments. Conclusions: As the mean expenses of both therapeutic options are compared, one clearly stands-out as less onerous. Clinical outcomes, when compared, reveal no statistical difference after each treatment. We concluded that, in HCPA, plasma exchange is more cost-effective than intravenous immunoglobulin.

Cette thèse se base sur des comparaisons du modèle de Besançon de la Galaxie avec des comptages d'étoiles en infrarouge proche. Nous avons premièrement ajusté 11 paramètres de densité du disque mince et du bulbe externe avec les observations DENIS, et montré que le bulbe externe est allongé et orienté d'environ 10° avec la direction du Soleil, et que le disque possède un trou central d'environ 2 kpc de rayon. Nous avons ensuite montré grâce aux données CAIN l'existence à l<27° d'une surdensité stellaire confinée près du plan qui pourrait correspondre à une barre.

Thesis (Ph. D.)--University of Oregon, 2008. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 179-185). Also available online in ProQuest, free to University of Oregon users.

Objetivo: Comparar as relações de custo-efetividade de duas terapias, Imunoglubulina Intravenosa (IgIV) e Plasmaferese (PE), no tratamento da Síndrome de Guillain-Barré sob a perspectiva do sistema público (SUS). O objetivo secundário foi avaliar a adesão às recomendações da Comissão de Medicamentos do HCPA Métodos: estudo transversal com análise econômica de pacientes tratados por Síndrome de Guillain-Barré no período de junho de 2003 a junho de 2008 no Hospital de Clínicas de Porto Alegre (HCPA). Foi realizada análise de custo-efetividade do emprego de IgIV e de PE nestes pacientes, pelo método de minimização de custos, considerando-se somente os custos diretos sanitários, fornecidos pelo sistema gerencial da instituição . Foram excluídos os pacientes que usaram outro tipo de tratamento associado ou isolado. Coletaram-se os dados através da revisão dos prontuários. A gravidade da doença na internação foi classificada como: doença leve, quando caminhar foi possível; doença moderada, quando caminhar foi impossível; doença grave, quando os pacientes necessitaram de ventilação assistida. A incapacidade na alta foi estabelecida pela escala de sete pontos de Hughes. A adesão às recomendações da Comissão de Medicamentos do HCPA, objetivo secundário, foi avaliada através da dose e o esquema de prescrição da IgIV. Resultados: Vinte e cinco participantes (2 a 70 anos) foram incluídos no estudo, cinco tratados com PE, empregando-se Albumina Humana como substituto do plasma, e 20 tratados com IgIV. O custo total do tratamento de um paciente com PE foi R$10.603,88 (± 2.978,12) e o de um que recebeu IgIV foi R$ 32.103,00 (± 21.454,24). O custo total da internação foi de R$45.027,14 (± 32.750,45) para os tratados com PE e de R$ 60.844,28 (±48.590,52) para os que receberam IgIV. Em relação ao desfecho clínico principal, melhora na escala de incapacidade de sete pontos, após o tratamento com uma das alternativas escolhida, a mediana dos pacientes que internaram com grau de gravidade 3 e que foram tratados com PE foi igual a dos que receberam IgIV. Em relação à permanência hospitalar, permanência em UTI e dias de Ventilação Mecânica, não houve diferença estatisticamente significativa entre os dois tratamentos. Conclusões: Quando comparados os custos médios das duas opções terapêuticas, uma delas aparece claramente com menor custo. Quando comparados os desfechos, após o emprego de cada opção terapêutica, estes não revelam diferença. Concluímos que, no HCPA, a opção pelo procedimento Plasmaferese é mais custo efetiva do que o emprego da IgIV. / Objectives: To compare the cost-effectiveness of two distinct therapies, Intravenous Immunoglobulin (IVIg) and Plasma Exchange (PE) in the treatment of Guillain-Barré Syndrome, concerning the public health care system. Compliance to the guidelines of the Pharmacy and Therapeutics Committee of the Hospital de Clínicas de Porto Alegre was a secondary objective. Methods: A cross-sectional, economical analysis was conducted, including patients treated for GBS in the period from June, 2003 through June, 2008 in Hospital de Clínicas de Porto Alegre (HCPA). The cost-effectiveness of the use of IVIg and PE in such patients was studied through the cost minimization method, considering direct medical costs only (2008 currency), yield by the management of the institution. Patients receiving treatments other than PE or IVIg were excluded. Data were collected by chart reviews. Severity of disease on admittance was classified as follows: mild disease, when the patient was able to walk; moderate disease, when the patient was unable to walk, and severe disease, when assisted ventilation was required. Disability on discharge was established by the 7-point scale of Hughes. Compliance to the guidelines of the Pharmacy and Therapeutics Committee was evaluated through the dose and prescription scheme of IVIg. Results: Twenty-five participants (2 to 70 years of age) were included in the study, 5 were submitted to treatment with PE, using human albumin as replacement for plasma, and 20 were treated with IVIg. The total treatment cost for PE in a single patient was US$6,058.85 (±1,701.78 SD), and the same expense for IVIg was US$18,344.57 (± 12,259.56 SD) (p = 0.035). Total inpatient cost was US$25,729.79 (± 18,714.54 SD) in the PE group, and US$34,768.16 (±27,766.01 SD) (p=0.530) in the IVIg group. The main clinical outcome was improvement in the 7-point disability grade scale. The median of that measure in patients admitted with a severity grade 3 treated either with PE and IVIg was the same. Secondary outcomes, such as in-hospital stay, ICU stay, and number of days on mechanical ventilation revealed no statistically significant difference between treatments. Conclusions: As the mean expenses of both therapeutic options are compared, one clearly stands-out as less onerous. Clinical outcomes, when compared, reveal no statistical difference after each treatment. We concluded that, in HCPA, plasma exchange is more cost-effective than intravenous immunoglobulin.

Après sa production dans des centrales, l'électricité est acheminée sur de longues distances à travers le réseau électrique qui comporte des appareils haute tension destinés à la protection des installations. Parmi ces dispositifs, le GIS (Gaz Insulated Switchgear), dans lequel l'isolation électrique est assurée par le gaz SF6, est très utilisé. Il est soumis à des normes de sécurité imposant, notamment, des seuils de température à ne pas dépasser durant son fonctionnement. La connaissance et la maîtrise des phénomènes électromagnétiques et thermiques à l'origine des augmentations de température dans le GIS sont des enjeux cruciaux. Elles permettent un dimensionnement plus rapide et plus précis des appareils, aboutissant à un unique essai de validation des critères fixés par les normes. Elles fourniront également des solutions visant à réduire les échauffements des GIS. Cette réduction est importante car elle permet la circulation d'un courant plus élevé dans le GIS, ce qui aboutit à une amélioration des performances de l'appareil. Les travaux effectués dans le cadre de cette thèse présentent une analyse des phénomènes électro-thermiques dans le GIS et plus précisément dans les jeux de barres. Ils permettent la détermination des paramètres influençant l'augmentation de température dans cette géométrie. La contribution de chaque mode de transfert de chaleur (convection, rayonnement) est estimée et discutée. Une modélisation numérique du champ de température induite par la circulation du courant dans les jeux de barres est également proposée, en tenant compte du couplage avec le champ de vitesse induit. / Electricity is produced by power stations and is transported throughout the electric-power transmission at long distances with high voltage apparatus. The GIS (Gas Insulated Switchgear) is widely used switchgear. The electric insulation is ensured by the gas SF6. Security IEC norms impose temperature rises not to be exceeded during GIS operating. It is important to know and control the electromagnetic and thermal phenomenons which generate temperature rises. The switchgear design could then be faster and more precise, leading to only one successful temperature rise test. Solutions to reduce temperatures could also be found. The temperature rise reduction is crucial as it allow a higher current flowing through the GIS and an increase of its efficiency. The word achieved during this thesis presents an analysis of electro-thermal phenomenons in GIS and, more precisely, in busbars. It leads to the determination of the parameters influencing temperature rises and of the heat transfers proportion which is assessed and discussed. A numerical modelization is carried out to examine the temperature rises induced by the current flow in busbars.