Made available in DSpace on 2014-06-11T19:25:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-08Bitstream added on 2014-06-13T20:14:00Z : No. of bitstreams: 1 santos_alr_me_guara.pdf: 967831 bytes, checksum: 8cbbf37b87afd6e4a7c7ecc3380f9ebf (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Materiais poliméricos têm sido amplamente utilizados em várias áreas tecnológicas e biomédicas, devido às suas excelentes propriedades mecânicas, térmicas e elétricas. No entanto, estes materiais têm baixa energia de superfície e, portanto, não aderem facilmente a outros materiais. Por isso, para muitas aplicações é necessário modificar a superfície do polímero, a fim de aumentar a sua energia de superfície. Tratamentos a plasma à pressão atmosférica têm sido muito utilizados para modificar as propriedades superficiais de polímeros comerciais, devido aos baixos custos do processo. Este trabalho apresenta os resultados do tratamento de tereftalato de polietileno (PET), poliuretano (PU) e de politetrafluoretileno (PTFE) em plasma de descargas com barreira dielétrica (DBD) em ar, nitrogênio e argônio, à pressão atmosférica. As superfícies tratadas foram caracterizadas por medidas de ângulo de contato, espectroscopia de fotoelétrons de raios-X (XPS) e microscopia de força atômica (AFM). A superfície polimérica, modificada nas DBD a pressão atmosférica, mostraram uma redução significativa no ângulo de contato da água, embora uma recuperação parcial da molhabilidade ocorresse nos primeiros dias após o tratamento. Todavia, a recuperação foi insuficiente para que as amostras tratadas recuperassem a sua molhabilidade original. Análises de XPS mostraram um aumento na concentração de oxigênio na superfície, devido à formação de grupos polares, tais como C-O e OC= O. Um pequeno aumento na concentração de nitrogênio também foi observada. Imagens de AFM mostraram um aumento da rugosidade de polímeros tratados, decorrentes da interação física entre as espécies geradas na descarga e a superfície do polímero. A superfície ativada e a elevada tensão superficial dos polímeros tratados devem levar a um aumento da aderência do polímero. / Polymeric materials have been widely used in various biomedical and technological applications, due to their excellent mechanical, thermal and electric properties. However, these materials have low surface energy, and thus not easily adhere to other materials. Therefore, for many applications it is necessary to modify the polymer surface in order to increase its surface energy. Plasma treatments at atmospheric pressure have been frequently used to modify the surface properties of commercial polymers, due to their low process costs. This work reports the results of polyethylene terephthalate (PET), polyurethane (PU) and polytetrafluoroethylene (PTFE) treatments in plasma by dielectric barrier discharges (DBDs) in air, nitrogen and argon at atmospheric pressure. The plasma-modified surfaces were characterized by contact angle measurements, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The polymer surface, modified by DBD at atmospheric pressure, showed a significant decrease in water contact angle although a partial recovery of the surface wettability occurred during the first few days after the treatment. However, the process of hydrophobic recovery was insufficient for complete recovering of the samples original wettability. XPS analysis showed an increase of the oxygen concentration on the surface, due to the formation of polar groups, such as C-O and OC= O. A small increase in the concentration of nitrogen was also observed. AFM images exhibit an increased roughness of the treated polymers because of the physical interaction between the species generated in the discharge and the polymer surface. The activated surface and high surface tension of treated polymers should promote an enhancement of the polymer adhesion to paints and coatings.

This Master Thesis work cover the simulation of the movement of charged species exposed to a high gradient electric field, the same environment a plasma actuator produces. The final goal is to use the plasma actuator as an active flow control device to decrease the drag of a body moving in air. This report describes how the problem was set up in COMSOL Multiphysics and the resulting volume force achieved. The volume force is the force generated by the plasma actuator that is acting on the air. To understand the effect of a plasma actuator better experimental work was also performed. The experimental work include what effect a plasma actuator has on a wing that has stalled out and measuring the air velocity obtained from a single plasma actuator. The conclusion is that more work has to be performed to make the plasma actuator a more effective flow control device. This type of work is a way to understand how plasma actuators work and in extension will lead to how a plasma actuator will be used effectively. / Detta examensarbete behandlar simuleringen om hur laddade partiklar rör sig när de utsätts för ett elektriskt fält med hög gradient, ett liknande närområde som skapas av en plasma aktuator. Slutmålet är att kunna använda plasma aktuatorer som en aktiv flödeskontroll med avsikt att minimera motsåndet på en stelkropp som rör sig genom luften. Den här rapporten beskriver hur problemet ställs upp i COMSOL Multiphysics och vilken volymkraft som fås utav simulerignen. Volymkraften är den genererade kraft från plasma aktuatorn som aggerar på den omgivande luften. Utöver simuleringen har praktiska experiment gjorts för att förstå effekten från en plasma aktuator bättre. Dessa experiment består av hur en plasma aktuator förändrar luftströmmen över en vinge som redan tappat sin lyftkraft och av att mäta vilken hastighet luften kan nå på grund av en plasma aktuator. Sammanfattnignen är att mer arbete behöver göras för att effektivisera en plasma aktuator om den ska användas för flödeskontrol. Detta arbeta är ett steg i att förstå hur plasma aktuatorer fungerar vilket i förlängningen kommer leda till hur man ska använda en plasma aktuator på bästa sätt.

The global occurrence of metabolic syndrome has reached epidemic proportions and is a contributing factor in the rising incidence of cognitive decline in the aging population. While pre-clinical research has advanced our understanding of many of the mechanisms underlying metabolic syndrome, animal models often do not reflect the complexity of human disease. For example, animal models that investigate the role played by diet in metabolic syndrome have generally focused on a single macronutrient, in particular fat or carbohydrate. As a result, although a balanced diet and increased physical activity are commonly recommended to treat metabolic syndrome symptomatology, their long-term cerebrovascular benefits are uncertain. To address these gaps in knowledge, a “Cafeteria” diet consisting of 16 common ultra-processed grocery store food items was used to model human metabolic syndrome in the rat. I compared rats fed a Cafeteria diet (CAF) to those fed “standard” chow (SD) as well as to a third group that underwent a switch to chow after chronic exposure to the Cafeteria diet (SWT). In a first study, I showed that three months of exposure to the Cafeteria diet produced metabolic syndrome as well as hippocampal neuroinflammation with increased microglial proliferation. These were fully reversed in SWT rats. Nonetheless, the Cafeteria diet did not worsen spatial learning and memory performance as assessed using the Barnes maze. In a second study, brain perfusion was examined using continuous arterial spin labeling magnetic resonance imaging (CASL MRI). Cortical and hippocampal resting perfusion was increased in CAF rats while cerebrovascular reactivity in response to a 10% CO2 vasodilatory challenge was reduced. Furthermore, while resting perfusion improved in SWT rats, cerebrovascular reactivity remained impaired. These cerebral blood flow outcomes were not accompanied by alterations in microvascular architecture or integrity as determined by rat endothelial cell antigen-1 (RECA-1) and immunoglobulin G (IgG) histology. Taken together, these results demonstrate that the Cafeteria diet is an effective model of metabolic syndrome that negatively impacts brain hemodynamic function. Moreover, while a dietary lifestyle intervention can recover peripheral features of metabolic syndrome, neuroinflammation, and resting perfusion, it is insufficient to completely reverse deficits in cerebrovascular reactivity. These findings are compelling as they speak to the detrimental effects of ultra-processed food consumption on cerebrovascular reserve capacity, believed to be an important factor in cognitive decline.

A umidade nas edificações pode ser proveniente de diversas fontes. Entre elas está a umidade ascensional, que provém do solo na ausência ou falha de barreiras. A umidade ascende pelas paredes por capilaridade existente devida a estrutura porosa dos materiais de construção. Sua ação pode prejudicar o desempenho das paredes das edificações, possibilitando a degradação progressiva das paredes. Dessa forma, estas podem deixar de cumprir funções, como por exemplo, de proteção e acabamento. Vários tratamentos têm sido estudados pelo mundo. Entretanto a avaliação dos métodos de reparação das paredes afetadas tem sido um problema de difícil resolução. O objetivo deste trabalho é a avaliação da eficiência do tratamento de paredes com umidade ascensional através do método de corte hídrico por inserção do cristalizante através da ação gravitacional, utilizando os diferentes produtos disponíveis no mercado nacional brasileiro. Apesar de limitada a paredes pouco espessas, essa técnica tem apresentado eficácia, versatilidade de execução e baixa interferência na fachada da parede. Essas características justificam a escolha dessa técnica para servir de objeto de estudo do presente trabalho. Visto que não há ensaio normalizado para avaliar a eficiência dos produtos para tratamento contra umidade ascensional será utilizado como referência um experimento realizado por outros pesquisadores, explanado neste documento. A avaliação da umidade presente no corpo de prova é através da medição da massa e imagens com câmera termográfica. Constatou-se que, no período analisado, não houve a redução total da umidade ascensional, no entanto os cristalizantes conseguiram diminuir consideravelmente (em média mais que 50%) a absorção da água por capilaridade. / Dampness in buildings can be derived from several sources. Among them is the upward moisture, which comes from the soil in absence of barriers. The moisture ascends on the walls due to the existing capillarity of porous building materials. Its action may impair the performance of the walls of buildings, leading to their progressive degradation. Thus, the walls may cease to comply with their functions, such as protecting and finishing. Several treatments have been studied worldwide. However, evaluating the methods of repairing affected walls has been a difficult problem to be solved. The aim of this study is to evaluate the efficacy of the treatment of walls presenting upward moisture through the method of the crystallizing insertion through gravitational action using different available products within the Brazilian market. In spite of being limited to thin walls, this technique has presented efficacy, versatility of execution and little interference on the treated facade as it has been demonstrated on the studied bibliography. These features justify choosing that technique to be studied in the present work. A reference experiment conducted by other researchers is used, since there is no standard test to evaluate the efficiency of treatment products rising damp against. The evaluation of the moisture present in the specimen is by measuring the mass and images with thermographic camera. It was found that in the period analyzed, there was no reduction of the total moisture upward. However the crystallizing managed to reduce significantly (on average more than 50%) the absorption of water by capillarity.

O aumento expressivo nos níveis de ruído, principalmente nas áreas urbanas próximas aos aeroportos, tem contribuído de forma preocupante para os já elevados e atuais níveis de poluição sonora registrados nos grandes centros urbanos. Além do fato dos incômodos e desconfortos no cotidiano das pessoas provocados por esse fato, as autoridades que tratam desse assunto alertam para os danos causados a saúde humana e dos seres vivos em geral. Alguns países europeus que estudam este assunto se dizem preocupados com os impactos negativos em suas economias na questão do desequilíbrio orçamentário no setor da saúde. A tese motivada pela utilização ampla de barreiras acústicas no setor de transporte rodoviário, ferroviário convencional e de alta velocidade, e, prioritariamente aéreo, pôde construir por intermédio desses contextos o conhecimento necessário e um cenário de expectativas promissoras com o objetivo de colaborar com a atenuação do ruído aeronáutico com uma proposta acadêmica de implantação de barreiras acústicas articuladas posicionadas nas cabeceiras da pista principal do Aeroporto de Congonhas em São Paulo no momento da decolagem, tendo como paradigma conceitual e operacional o uso similar dos defletores de energia que são utilizados nos conveses dos porta-aviões no momento das suas decolagens. / The significant increase in noise levels, especially in urban areas close to airports, has contributed to the alarmingly high already and current noise pollution levels recorded in major urban centers. Besides the fact of annoyances and discomforts in the everyday life of people caused by this fact, the authorities dealing with this subject warn of the damage to human health and living creatures in general. Some European countries who study this issue claim to be concerned about negative impacts on their economies on the question of the budget imbalance in the health sector. Some European countries who study this issue claim to be concerned about negative impacts on their economies on the question of the budget imbalance in the health sector. The thesis motivated by wide use of noise barriers in the road transport sector, conventional and high-speed rail, and, as a matter of priority air could build through these contexts the knowledge necessary and a promising expectations scenario with the objective of collaborating with the aeronautical noise attenuation with an academic proposal to implement noise barriers at the headwaters of the track positioned hinged main from Congonhas Airport in Sao Paulo at the time of takeoff with the conceptual and operational paradigm using similar energy deflectors that are used on the decks of the carrier at the time of their landings.

A umidade nas edificações pode ser proveniente de diversas fontes. Entre elas está a umidade ascensional, que provém do solo na ausência ou falha de barreiras. A umidade ascende pelas paredes por capilaridade existente devida a estrutura porosa dos materiais de construção. Sua ação pode prejudicar o desempenho das paredes das edificações, possibilitando a degradação progressiva das paredes. Dessa forma, estas podem deixar de cumprir funções, como por exemplo, de proteção e acabamento. Vários tratamentos têm sido estudados pelo mundo. Entretanto a avaliação dos métodos de reparação das paredes afetadas tem sido um problema de difícil resolução. O objetivo deste trabalho é a avaliação da eficiência do tratamento de paredes com umidade ascensional através do método de corte hídrico por inserção do cristalizante através da ação gravitacional, utilizando os diferentes produtos disponíveis no mercado nacional brasileiro. Apesar de limitada a paredes pouco espessas, essa técnica tem apresentado eficácia, versatilidade de execução e baixa interferência na fachada da parede. Essas características justificam a escolha dessa técnica para servir de objeto de estudo do presente trabalho. Visto que não há ensaio normalizado para avaliar a eficiência dos produtos para tratamento contra umidade ascensional será utilizado como referência um experimento realizado por outros pesquisadores, explanado neste documento. A avaliação da umidade presente no corpo de prova é através da medição da massa e imagens com câmera termográfica. Constatou-se que, no período analisado, não houve a redução total da umidade ascensional, no entanto os cristalizantes conseguiram diminuir consideravelmente (em média mais que 50%) a absorção da água por capilaridade. / Dampness in buildings can be derived from several sources. Among them is the upward moisture, which comes from the soil in absence of barriers. The moisture ascends on the walls due to the existing capillarity of porous building materials. Its action may impair the performance of the walls of buildings, leading to their progressive degradation. Thus, the walls may cease to comply with their functions, such as protecting and finishing. Several treatments have been studied worldwide. However, evaluating the methods of repairing affected walls has been a difficult problem to be solved. The aim of this study is to evaluate the efficacy of the treatment of walls presenting upward moisture through the method of the crystallizing insertion through gravitational action using different available products within the Brazilian market. In spite of being limited to thin walls, this technique has presented efficacy, versatility of execution and little interference on the treated facade as it has been demonstrated on the studied bibliography. These features justify choosing that technique to be studied in the present work. A reference experiment conducted by other researchers is used, since there is no standard test to evaluate the efficiency of treatment products rising damp against. The evaluation of the moisture present in the specimen is by measuring the mass and images with thermographic camera. It was found that in the period analyzed, there was no reduction of the total moisture upward. However the crystallizing managed to reduce significantly (on average more than 50%) the absorption of water by capillarity.

Abstract In Oulu University Hospital Haematological Ward during the years 1990–1991, a manual blood culture system was able to detect bloodstream infection (BSI) in 23% of febrile episodes of patients with acute myeloid leukaemia (AML), whereas during the years 1992–1993 an automated continuous-monitoring blood culture system (CMBCS) BacT/Alert® detected BSI in 40% of febrile episodes (p = 0.043). During the years 1997–2003, regimens containing high-dose cytarabine predisposed patients to laboratory-confirmed BSI (LCBI) with an odds ratio (OR) of 2.3 (with 95% confidence interval (CI) from 1.2 to 4.2). The LCBI risk was lowest after thioguanine-containing regimens (OR 0.26, 95% CI; 0.12–0.58). In the register data (years 1992–2006) from the prospective multi-centre AML -92 trial, when compared to cycle I, the OR for LCBI was significantly higher (from 4.8 to 5.8) in subsequent cycles (p < 0.001). In all, 67% of mortality due to BSI occurred in patients with active leukaemia. An inoculum of microorganisms to produce 10 colony-forming units (cfu)/ml of 10 gram-positive coccal strains, 10 gram-negative bacillar strains and 8 Candida yeast strains was cultured in BacT/Alert® blood culture bottles in the presence of several chemotherapeutic drugs. Of the chemotherapeutic drugs tested, the anthracyclines exhibited inhibitory effects on the growth of microorganisms in concentrations corresponding to the therapeutic levels. In the standard bottles, doxorubicin increased the incubation time of gram-positive cocci and idarubicin increased the incubation time of Candida glabrata. However, no increase in the incubation time of any microbes was detected in the antimicrobial-neutralizing FAN bottles. In conclusion, the use of CMBCSs has resulted in an increased LCBI rate in neutropenic AML patients. In general, chemotherapeutic agents have no significant inhibitory effects on the growth of common microbial pathogens in blood culture. The detection of some difficult-to-culture microbial strains – C. glabrata for example – in blood cultures may be impaired by the presence of chemotherapeutics in blood. The chemotherapeutics may also affect the LCBI rate in other ways. As a predictor of adverse outcome of infection, the presence of active leukaemia is more important than the type of chemotherapy being administered.

The blood-brain barrier BBB refers to the set of specialized endothelial cells that line the vasculature in the brain and effectively control movement of molecules into and out of the brain. While necessary for proper brain function, the BBB blocks 98% of drugs from entering the brain and is the most significant barrier to developing therapies for neurodegenerative diseases. Active transport allows some specific molecules to cross the BBB, but therapeutic development using this route has had limited success. A number of techniques have been used to bypass the BBB, but are often highly invasive and ineffective. Over the last two decades, a minimally invasive technique to transiently open the BBB has been under development that utilizes transcranial focused ultrasound (FUS) in combination with intravascular microbubble contrast agents. This method is often carried out in conjunction with magnetic resonance imaging (MRI) to guide and assess BBB opening and has been referred to as MRI guided FUS (MRgFUS). Because of the utility of mouse models of neurological disease and the exploratory nature of MRgFUS, systems that allow BBB opening in mice are a useful and necessary tool to develop and evaluate this method for clinical application. In this dissertation project, a custom built, cost-effective FUS system for opening the BBB in mice was developed, with the objective of using this device to deliver therapeutics to the brain. Being a custom device, it was necessary to evaluate the ultrasound output, verify in vivo safety, and anticipate the therapeutic effect. The scope of the work herein consists of the design, construction, and evaluation of system that fulfills these requirements. The final constructed system cost was an order of magnitude less than any commercially available MRgFUS system. At this low price point, the hardware could allow the implementation of the methodology in many more research areas than previously possible. Additionally, to anticipate the therapeutic effect, molecules of pharmacologically-relevant sizes were delivered to brain with a novel, multispectral approach. Results demonstrated that the device was able to safely open the BBB, and macromolecule delivery showed that both molecule size and FUS pressure both influence the amount and distribution of molecules in the brain. Using different ultrasound pressures, the threshold for BBB opening was found to be ≥ 180 kPa (0.13 MI). The threshold for damage was found to be ≥ 420 kPa (0.30 MI), and was minor at this pressure, but extensive for higher pressure (870 kPa, 0.62 MI), in which minor damage was caused by this pressure. Performing a novel implementation of a diffusion model on the fluorescence images of 500, 70, and 3 kDa dextran resulted in calculated diffusion coefficients of 0.032 ± 0.015, 12 ± 6.0, and 0.13 ± 0.094 square microns per second, respectively.

Les revêtements barrières thermiques sont de plus en plus employés dans l'industrie afm d'accroître lesperformances thermiques et de diminuer les émissions de NOx des turbines aéronautiques et de générationd'électricité. Au cours de cette étude, le système constitué d'un substrat en superalliage base nickelmono cristallin AMI, d'une sous-couche NiAlPt et d'une barrière thermique en zircone yttriée élaborée par voieEBPVD (Electron Bearn Phase Vapor Deposition) a été étudié. Le but de cette thèse était de caractériser lesmodes d'endommagements en conditions représentatives de celles rencontrées en service sur le profil des aubesde turbines hautes pressions. Pour pallier au manque de données dans la littérature ouverte, des essais à différentsniveaux de température et de chargement mécanique ont été réalisés avec pour objectif de découpler les diversmodes d'endommagement qui entrent en jeu dans la ruine des barrières thermiques. Ces essais mécaniques detype fluage isotherme, fluage cyclé thermiquement, fatigue oligocyclique et fatigue avec temps de maintien ontété réalisés dans la gamme de température 950°C-1200°C avec des moyens d'essais classiques de laboratoire. Ilsont permis de mettre en évidence l'impact du chargement mécanique sur la cinétique de croissance de la couched'alumine inter faciale à llOO°C(notamment en fluage) mais aussi le délaminage à l'interface sous-coucheinterne/sous-couche externe en conditions de forte vitesse de déformation viscoplastique du substrat et le rôlemajeur de l'interdiffusion entre sous-couche et substrat sur la durée de vie en fatigue oligocyclique à 950°C. Desessais technologiques ont aussi été réalisés sur le banc MAATRE. / Thermal barrier coatings are widely used in the industry to enhance thermal performances and to decrease NOxemissions of aeronautic gas and electricity generating turbines. During this study, the system consisting of asingle crystal nickel based superalloy AMI (substrate), of a NiAIPt bondcoat and an yttria-stabilized zirconiatopcoat made by columnar EBPVD (Electron Bearn Phase Vapor Deposition) was studied. The aim ofthis thesiswas to characterize the damage mechanisms in conditions representative of those encountered in service on theprofile of high pressure turbine blades. To overcome the lack of data in the open literature, tests at differentlevels oftemperature and mechanicalloading has been made with the aim to decouple the various damage modesthat are involved in degradation of thermal barrier coatings. Thermomechanical testings such as isothermal creeptests, thermally cycled creep tests, low cycle fatigue with or without holding time have been made in thetemperature range 950°C-1200°C with conventional laboratory testing methods. They allowed to demonstratethe impact of the mechanical loading on the oxidation kinetics of the thermally grown oxide at IIOO°C(particularly during creep tests) but also a new delamination mode in the bond coat (near process defaults) in caseof high viscoplastic deformation rate of the substrate and the major role of interdiffusion between bondcoat andsubstrate on the low cyclic fatigue lifetime at 950°C. Finally, technological testings have also been realized onthe MAA TRE test bench.

Increased exposure to ambient particulate matter (PM) is associated with elevated morbidity and mortality in patients with cardiopulmonary diseases and cancer. We and others have shown that PM induces lung microvascular barrier dysfunction which potentially enhances the systemic toxicity of PM. However, the mechanisms by which PM disrupts vascular endothelial integrity remain incompletely explored. We hypothesize that PM induces endothelial cell (EC) cytoskeleton rearrangement via Rho GTPase-dependent pathways to facilitate vascular hyperpermeability. Fine PM induced time-dependent activation of cytoskeletal machinery with increases in myosin light chain (MLC) phosphorylation and EC barrier disruption measured by transendothelial electrical resistance (TER), events attenuated by the Rho-dependent kinase (ROCK) inhibitor Y-27632 or the reactive oxygen species (ROS) scavenger, N-acetylcysteine (NAC). Both Y-27632 and NAC prevented PM-induced stress fiber formation and phospho-MLC accumulation in human lung ECs. PM promotes rapid accumulation of Rho-GTP. This event is attenuated by NAC or knockdown of RhoA (siRNA). Consistent with ROCK activation, PM induced phosphorylation of myosin light chain phosphatase (MYPT) at Thr850, a post-translational modification known to inhibit phosphatase activity. Furthermore, PM activates the guanine nucleotide exchange factor (GEF) for Rho, p115, with p115 translocation to the cell periphery, in a ROS-dependent manner. Together these results demonstrate that fine PM induces EC cytoskeleton rearrangement via Rho-dependent pathways that are dependent upon the generation of oxidative stress. As the disruption of vascular integrity further contributes to cardiopulmonary physiologic derangements, these findings provide pharmacologic targets for prevention of PM-induced cardiopulmonary toxicity.