Os médicos têm solicitado grande número de formulações diferenciadas, sob a forma de cápsulas de liberação lenta ou prolongada, aos farmacêuticos magistrais, com o objetivo de atender as necessidades específicas dos pacientes. Considerando que, praticamente, não há estudos sobre a liberação de fármacos a partir de formas magistrais de liberação prolongada, neste estudo, cápsulas de liberação modificada com 100 mg de teofilina foram preparadas com diferentes polímeros como os derivados celulósicos (Methocel® K100MPRCR, K15MPRCR e E4MCR) em diferentes concentrações, 15-35%. As cápsulas foram manipuladas, empregando o método volumétrico de enchimento de cápsulas. A lactose, de natureza hidrofílica, foi utilizada como diluente, quando necessário. Para o controle de qualidade das cápsulas, determinações de peso médio e teor de fármaco foram realizados nas 17 formulações desenvolvidas. A avaliação da dissolução das cápsulas foi feita de acordo com a Farmacopéia Americana 26 ed., para cápsulas de liberação prolongada (Teste 8), empregando aparato 1 (cesta), rotação de 100 rpm e temperatura mantida a 37ºC ± 0,5 em 900 mL de meio fluido intestinal sem enzimas (pH 7,5). Os perfis de dissolução foram comparados ao de duas especialidades farmacêuticas, sob a forma de cápsulas liberação prolongada. A formulação obtida com 35% da capacidade em volume de Methocel® E4MCR para cápsulas de tamanho 01 e lactose como diluente, evidenciou perfil de liberação de acordo com as especificações estabelecidas, sendo possível obter resultados reprodutíveis com 10 lotes da mesma formulação, através da padronização dos procedimentos adotados durante a manipulação dos mesmos. Por outro lado, as formulações comerciais de cápsulas de liberação prolongada contendo 100 mg de teofilina sob a forma de microgrânulos, quando submetidas ao mesmo ensaio de dissolução, apresentaram rápida liberação do fármaco, indicando que nestas formulações a liberação do fármaco não é fator limitante para a absorção. Para a avaliação da cinética de liberação do fármaco foram aplicados os modelos matemáticos de ordem zero, primeira ordem e Higuchi. Concluiu-se que as matrizes obtidas com os polímeros foram capazes de modular a liberação de teofilina envolvendo os mecanismos de difusão e erosão, prevalecendo o modelo de ordem um. / Pharmacists are called upon by physicians to compound a wide range of different products, including extended-release and slow-release capsules, when patients require specific individualized therapy. Considering that, practically, there aren\'t studies about compounded extended-release dosage forms, in this study, extended-release capsules of theophylline (100 mg) were prepared with different polymers as cellulose (Methocel® K100MPRCR, K15MPRCR e E4MCR) at different concentrations (15-35%). A hand filling relative volume process was used to prepare the matrix capsules. Lactose was used as hydrophilic diluent. For the quality control of capsules, average weight and assay were performed in 17 formulations. Dissolution rate of these capsules were evaluated according to United States Pharmacopeia 26 ed., dissolution method for theophylline extended-release capsules (Test 8). Determinations were performed with apparatus 1 (basket), agitation at 100 rpm and 900 mL of intestinal medium without enzimes (pH 7,5) were kept at 37ºC ± 0,5ºC. Dissolution profiles were compared to two other commercial extended-release capsules. The batch of capsules compounded with 35% volume capacity to capsules size number 1 of Methocel® E4MCR and with lactose as excipient showed dissolution profile according to the especifications and it was possible to reproduce the same results with more ten batches, through the standardized compounding procedure. On the other hand, commercial extended-release capsules containing theophylline pellets (100 mg) showed quick drug release, indicating that the drug release is not a limitant factor to the absorption. Mathematical models like zero¬-order, first-order and Higuchi were applied in kinetic studies of theophylline release from the capsules. The evaluation indicated that the polymers were efficient to control the release of theophylline in capsules and the involved mechanisms were diffusion and erosion and first-order was the model that better fitted for theophylline matrix capsules.

Staphylococcus aureus, pathogène opportuniste de l’homme, est responsable de 30% des infections nosocomiales. L’apparition de souches multi résistantes aux antibiotiques en font un problème majeur de santé publique. La pathogénie de la bactérie résulte de l’expression d’une pléthore de facteurs de virulence, mais quels sont les mécanismes de régulation contrôlant l’expression de ces gènes ? Aujourd’hui, il est clairement établi que les ARN non-codant sont des molécules clés dans la régulation de l’expression des gènes. Plus de 50 ARN ont été identifiés chez S. aureus. Néanmoins la fonction de peu d’entre eux est connue. Durant ce travail de thèse, l’étude de la fonction et du mécanisme de régulation des ARN RsaA et RsaE a été entreprise. RsaA est un ARN sous le contrôle du facteur de stress sigmaB. Les résultats obtenus montrent que ce dernier régule la traduction de l’ARNm mgrA qui code pour un facteur de transcription important dans l’expression des gènes de virulence et la régulation de l’autolyse. Par appariement de base, RsaA cible l’ARNm en utilisant deux sites distants et coopératifs, permettant un interaction forte qui empêche la traduction de l’ARNm. In vivo, la délétion du gène rsaA perturbe la synthèse de biofilm de capsule. En régulant la traduction de sa cible, RsaA permet de relier l’adaptation au stress à l’expression des gènes de virulence. De manière plus générale, les réseaux de régulation des ARN se connectent les uns aux autres pour permettre à la bactérie d’intégrer une multitude de signaux provenant du milieu extracellulaire afin de moduler finement l’expression des gènes. / Staphylococcus aureus is a versatile and opportunist human pathogen, which is responsible of 30% of nosocomial infections. S. aureus is today an important public safety concern due to high persistence rate in hospital combined with emergence of multi resistant strains against antibiotics. The pathogenicity of the bacteria results from the expression of numerous virulence factors. An importance focus has been made to understand what triggers virulence genes expression. Regulatory RNAs are important regulators of genes expression in bacteria. In S. aureus, there is more than 50 RNAs identified, but there is a lack of investigations about their functions and regulatory networks. The aim of this work was to characterize the function and mechanism of action of RsaA and RsaE RNAs. RsaA is under the control of the stress factor sigma B. Computational analysis combined with global analysis of the proteome led to the discovery of one target : mgrA mRNA, which is a global transcription factor involved in autolysis and biofilm regulation. In vitro studies show that RsaA binds efficiently mgrA mRNA using two distant and cooperative interaction sites. Binding of RsaA to the mRNA prevents initiation of the translation. In vivo, rsaA gene deletion shows impact on biofilm and capsule production. By regulating the expression of mgrA mRNA, RsaA network is linked to agr system and virulence gene expression. In a more general way, this work shows that regulatory RNAs networks allow bacteria to modulate virulence, stress and metabolism gene expression depending on the signals provided by the environment of the bacteria.

Made available in DSpace on 2016-03-15T14:17:05Z (GMT). No. of bitstreams: 2 8.pdf: 1534647 bytes, checksum: 1019d0b569bd76175c0f5781ad404d58 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2012 / Fundação Oswaldo Cruz. Instituto de Tecnologia em Fármacos/Farmanguinhos. Rio de Janeiro, RJ, Brasil. / Atualmente, há uma crescente demanda pela disponibilidade de produtos fitoterápicos, para atender tanto o mercado privado quanto a inserção destes produtos no Sistema Único de Saúde. Para a indústria de medicamentos envolvida com a fabricação de fitoterápicos em escala, a estratégia de produção está hoje delineada pela utilização de extratos secos padronizados de espécies medicinais, sob a forma de cápsulas. As cápsulas duras comerciais mais disseminadas são elaboradas a partir de gelatina, que apresentam uma grande limitação de sua eficiência quando o material a ser encapsulado tem características higroscópicas, pois a gelatina é reconhecida por formar ligações cruzadas em condições de alta umidade e temperatura. Este fato tem sido um fator limitante para a indústria farmacêutica, especialmente no que tange à veiculação de extratos vegetais secos, desde que muitos fitoterápicos constituem pós extremamente higroscópicos, o que em última análise compromete a estabilidade do medicamento fitoterápico. O presente estudo teve como objetivo avaliar a eficiência de cápsulas de hipromelose e de gelatina contendo extrato padronizado comercial de Sene (Cassia angustifolia Vahl). As cápsulas de ambos os tipos foram submetidas ao estresse térmico acelerado a 35 graus Celsius (ºC) e 65% de umidade relativa (UR) e a 40ºC/75%U.R. por 6 meses. As medidas comparativas de estabilidade consistiram nas avaliações de (i) perda por dessecação, (ii) desintegração, (iii) suscetibilidade à quebra, (iv) atividade de água, (v) contaminação microbiana, e (vi) análise dos derivados hidroxiantracênicos e dos senosídeos A e B. Os testes físico-químicos foram realizados de acordo com os métodos farmacopeicos em vigor, e a comparação dos conteúdos químicos foi avaliada quantitativamente por Cromatografia Líquida de Alta Eficiência (CLAE), utilizando como marcadores os senosídeos A e B comerciais, cujas presenças nos extratos foram corroboradas com a CLAE acoplada à espectrometria de massas. Os resultados obtidos na caracterização física demonstraram que as cápsulas de hipromelose apresentaram maior estabilidade em todos os parâmetros estudados, quando comparadas as de gelatina. Os resultados da análise química apontaram uma queda maior no teor de senosídeo B para as cápsulas de gelatina em relação às de hipromelose: 0,021% e 0,022%, 30ºC/65%UR e 0,02% e 0,017% 40ºC/75% UR, respectivamente. Estes resultados demonstram preliminarmente que há vantagens no uso da cápsula hipromelose em relação à de gelatina para encapsular o extrato seco de Sene, em um estudo de estabilidade acelerada, no entanto outras avaliações serão necessárias, incluindo um estudo de estabilidade completo no produto. / Currently there is a growing demand for the availability of herbal products to meet both the private market and the inclusion of these products in the Unified Health System. For the pharmaceutical industry involved in the manufacture of herbal medicines in scale, the production strategy is outlined today by the use of standardized dry extracts of medicinal species in the form of capsules. The most widespread commercial hard capsules are made from gelatin, which present a major limitation of its efficiency when the material to be encapsulated has hygroscopic characteristics, because the gelatin is known to form cross-linking under conditions of high humidity and temperature. This has been a limiting factor for the pharmaceutical industry, especially in regard to the placement of dry plant extracts, since many herbal powders are highly hygroscopic, which ultimately compromises the stability of herbal medicine. The present study aimed to evaluate the efficiency of capsules of hypromellose and gelatin containing commercially standardized Senna dry extract (Cassia angustifolia Vahl.). The capsules of both types were subjected to accelerated heat stress at 35 Celsius degrees (°C) / 65% relative humidity (RH) and at 40ºC / 75%RH for 6 months. The comparative measures of stability in the evaluations consisted of (i) loss on drying, (ii) disintegration, (iii) susceptibility to breakage, (iv) water activity, (v) microbial contamination, and (vi) analysis of hydroxyanthracene derivatives and senosídes A and B. The physicochemical tests were performed according to the pharmacopoeial methods in place, and the comparison of chemical content was assessed quantitatively by High Performance Liquid Chromatography (HPLC), using commercial senosídeos A and B as chemical markers, whose presence in the extracts were corroborated by HPLC coupled with mass spectrometry. The results of the physical characterization of the capsules showed that hypromellose capsules showed a higher stability in all these parameters, when compared with gelatin. The chemical analysis results showed a greater decrease in the concentration of senoside B for gelatin compared to hypromellose capsules: 0.021% and 0.022%, 30 ºC/65% R.H. and 0.02% and 0.017% 40 ºC/75% R.H., respectively. These preliminary results show that there are advantages in the use of hypromellose capsule in relation to the gelatin to encapsulate the Senna dry extract in an accelerated stability study, but further evaluation will be needed, including a complete study of stability in the product.

A cápsula endoscópica é um instrumento revolucionário, que permite a realização de um exame livre de desconfortos para o paciente e possibilitou a técnica de endoscopia chegar a partes do sistema gastrointestinal que antes não era possível, como grande parte do intestino delgado. Este trabalho apresenta um módulo fotônico para realizar Terapia Fotodinâmica (PDT, Photodynamic Therapy) em cápsulas endoscópicas. A PDT é uma forma de tratamento para lesões que envolve a administração prévia de um medicamento fotossensível (PS, Photosensitizer) e posterior ativação com irradiação de luz em um comprimento de onda (λ) específico. Geralmente para a ativação do PS utiliza-se λ na região vermelha do espectro visível, pois a penetração nos tecidos é elevada. Células de adenocarcinoma gástrico humano (AGS, Adenocarcinoma Gastric of Stomach) foram preparadas com ácido 5-aminolevulínico (5-ALA) que é um Pró-fármaco precursor do agente fotossensível Protoporfirina IX (PpIX) com máximo de absorção nos 635 nm. Para realizar a irradiação com luz vermelha nas células, 16 LEDs do modelo LRQ396-P1Q2-1 da Osram Opto Semiconductors com dimensões muito reduzidas foram selecionados, caracterizados, montados em uma PCB (Printed Circuit Board) e alimentados por um Arduino Mega 2560. Este sistema de iluminação foi eficaz em seu propósito e causou morte celular nas células submetidas ao tratamento com o ALA em uma concentração de 2 milimol por litro e dose de luz em 5 Joules por centímetro quadrado que resulta em uma exposição de 49 minutos. Com o objetivo de se construir um módulo para controle de iluminação em cápsulas endoscópicas, foi desenvolvido em tecnologia CMOS 0.7 μm da ON Semiconductor um dispositivo capaz de controlar a intensidade dos LEDs utilizando PWM (Pulse Width Modulation). Unindo este componente com os LEDs selecionados é perfeitamente possível construir o módulo e inseri-lo CEs para realizar PDT em locais do trato gastrointestinal (GI) não acessíveis pela endoscopia convencional. / The endoscopic capsule is a revolutionary instrument that gives a free examination of discomforts for patient and allows the endoscopic technique to reach parts of the gastrointestinal system that were previously not possible, such as a large part of the small intestine. This work presents a photonic module to perform Photodynamic Therapy (PDT) in endoscopic capsules. PDT is a form of treatment for injuries involving prior administration of a photosensitive drug (PS, Photosensitizer) and subsequent activation with light irradiation at a specific wavelength (λ). Usually for PS activation, λ is used in the red region of the visible spectrum, because the tissue penetration is high. Human gastric adenocarcinoma cells (AGS) were prepared with 5-aminolevulinic Acid (5-ALA) which is a Pro-drug precursor of the photosensitive agent Protoporphyrin IX (PpIX) with maximum absorption at 635 nm. To perform red light irradiation on the cells, 16 LEDs, model LRQ396-P1Q2-1 of the Osram Opto Semiconductors with very small dimensions were selected, characterized, mounted on a PCB (Printed Circuit Board) and powered by an Arduino Mega 2560. This system was effective in its purpose and caused cell death in cells treated with ALA at a concentration of 2 mMol/L and dose of light at 5 J/cm² resulting in a 49 minutes exposure. With the objective of build a module for control of lighting in endoscopic capsules, a device able to controlling the intensity of the LEDs using PWM (Pulse Width Modulation) was developed in CMOS technology 0.7 μm of the ON Semiconductor. Combining this component with the selected LEDs, it is perfectly possible to construct the module and insert in CEs to perform PDT at sites of the gastrointestinal tract (GI) not accessible by conventional endoscopy.

A agricultura demanda grande quantidade de água para a produção de alimentos e fibras. Técnicas que determinem e monitorem a dinâmica da água no solo são importantes para promover o uso correto e consciente desse recurso natural. Diante do exposto, a tensiometria é uma ferramenta eficiente na determinação da dinâmica da água em solos agrícolas, podendo ser utilizada em conjunto com sensores de capacitância para a caracterização da curva de retenção de água no solo. Contudo, apesar de práticos, erros associados à instalação e às características das cápsulas podem comprometer a precisão dos tensiômetros. Esse trabalho teve como objetivo testar a influência do uso de lama de solo no momento da instalação, bem como o formato e condutância hidráulica de cápsulas de tensiômetros de punção sobre o potencial matricial da água no solo, tendo-se como referência tensiômetros com manômetro de mercúrio. Também, se objetivou determinar a curva de retenção de água no solo com base nos dados obtidos por tensiometria e de um sensor de capacitância. Os resultados mostram que o formato das cápsulas de cerâmica e a lama de solo influenciaram as determinações do potencial matricial, ao contrário da condutância hidráulica das cápsulas. A lama de solo é indicada na instalação de tensiômetros com manômetro de mercúrio e de punção. As curvas de retenção diferiram quanto aos sistemas de aquisição (manômetro de mercúrio ou tensímetro); no entanto, o modelo ajustado não foi sensível em distinguir diferenças entre os tratamentos quanto ao formato das cápsulas ou uso de lama de solo. De modo geral, ocorreu uma subestimativa dos ajustes das curvas de retenção para os tensiômetros de punção, o que pode levar a interpretações errôneas das curvas de retenção de água no solo quando determinadas por meio desses instrumentos. / The agriculture demand large amounts of water for food and fiber production. The techniques used to determine and monitor the water dynamics in the soil are important to promote the correct and conscious use of this natural resource. Given the above, the tensiometry is an efficient tool for the determination the water dynamics in soils, which can be used in conjunction with capacitance sensors to characterize the water retention curve in the soil. However, although practical, errors associated with the installation and the characteristics of the capsules may compromise the accuracy of tensiometers. This study aimed to test the influence of the use of soil slurry during the tensiometer installation, the format and hydraulic conductance of the capsules from puncture tensiometers on the matric potential of soil water, taking as reference tensiometers equipped with mercury manometers. In addition, aimed to determine the soil-water retention curve based on data obtained by tensiometry and a capacitance sensor. The results shows that the format of the ceramic capsules and the use of the slurry influenced the measurements of matric potential, as opposed to hydraulic conductance of the capsules. The soil slurry is recommended for tensiometers equiped with mercury manometer and puncture tensiometers. The retention curves differed among the acquisition systems (mercury manometer or tensimeter); however, the fitted model was not sensitive enough to distinguish differences between treatments for the format of the capsules or the use of soil slurry. In general, there was an underestimation of the retention curve for puncture tensiometers, which can lead to erroneous interpretations of the soil-water retention curve when determined by these instruments.

INTRODUÇÃO: O esôfago de Barrett (EB) é uma patologia que aumenta substancialmente o risco de adenocarcinoma esofágico. Os pacientes portadores de EB devem ser seguidos ao longo de toda a vida na tentativa da detecção de neoplasia em estágio precoce. A endoscopia digestiva alta (EDA) é, atualmente, o método de eleição. OBJETIVO: Avaliar a eficácia da cápsula endoscópica do esôfago (CEE) comparada à EDA com cromoscopia com azul de metileno para detecção de lesões suspeitas de neoplasia esofágica, avaliação da extensão e padrão do EB, e identificação da presença de hérnia de hiato; além de comparar a segurança e grau de desconforto dos dois métodos. MÉTODOS: Estudo de casos transversal, realizado em 22 pacientes sabidamente portadores de EB que foram submetidos à fundoplicatura à Nissen há mais de 5 anos. Os pacientes realizaram os exames de CEE e EDA com cromoscopia esofágica por médicos diferentes e desconhecedores dos achados do outro exame. Após a realização dos exames, foi aplicado um questionário onde foi anotado o grau de desconforto do paciente em cada exame e eventuais complicações. Foi avaliado o índice de concordância (kappa) entre os dois métodos para pesquisa de lesões suspeitas de neoplasia esofágica, características do EB e detecção de hérnia hiatal. RESULTADOS: Dezenove pacientes completaram o estudo. A CEE apresentou sensibilidade e valor preditivo negativo de 100% e acurácia de 79% para detecção de lesão suspeita de neoplasia esofágica e concordância razoável com EDA (kappa = 0,27). A acurácia da CEE para avaliação da extensão do EB foi de 89% e concordância moderada (kappa = 0,60) com EDA. A acurácia da CEE para avaliação de EB digitiforme, circunferencial e misto foram, respectivamente, 74%, 79% e 74% com concordância moderada nos casos de EB circunferencial e misto e não significante no EB digitiforme. Quanto à detecção de hérnia de hiato a CEE apresentou sensibilidade de 43% e acurácia de 74%, com concordância razoável (kappa = 0,38) com EDA. Não houve diferença estatística de desconforto entre os exames e não houve complicação em ambos os métodos endoscópicos. CONCLUSÕES: A CEE mostrou-se um bom método de detecção de lesões suspeitas de neoplasia esofágica. Quanto a avaliação da extensão e padrão do EB, a CEE apresentou resultados razoáveis, quando comparada à EDA com cromoscopia esofágica. A CEE apresentou resultados insatisfatórios quanto à detecção de hérnia hiatal. Não houve diferença significativa de desconforto entre CEE e EDA. Os dois métodos mostraram-se seguros / INTRODUCTION: Barrett\'s esophagus (BE) is a condition that substantially increases the risk of esophageal adenocarcinoma. Patients with BE should be followed throughout life in an attempt to detect cancer at an early stage. Upper gastrointestinal endoscopy (GIE) is currently the method of choice. OBJECTIVE: To evaluate the efficacy of esophageal capsule endoscopy (ECE) compared to methylene blue (MB) chromoendoscopy for detection of suspicious lesions of esophageal cancer, evaluation of extent and pattern of BE, and identifying the presence of hiatal hernia, in addition to compare the safety and patients discomfort of the two methods. METHODS: Transverse study, conducted on 22 Barretts patients submitted to Nissen fundoplication with more than five years follow-up. Patients underwent examinations of ECE and MB chromoendoscopy by different physicians blinds to each procedures. After the exams, patients discomfort and possible complications that occurred in each method were recorded. It was evaluated the concordance index between the two methods for detection of suspicious lesions of esophageal cancer, extent and pattern of BE and hiatal hernia detection. RESULTS: Nineteen patients completed the study. The ECE sensitivity, negative predictive value and accuracy were, respectively, 100%, 100% and 79% for detecting suspicious lesion of esophageal cancer and had reasonable agreement with MB chromoendoscopy (kappa = 0.27). The ECE accuracy for assessing the extent of BE was 89% and had moderate agreement (kappa = 0.60) with MB chromoendoscopy. The accuracy of the ECE for evaluation of finger-like, circumferential, and mixed BE were respectively 74%, 79% and 74%, and moderate agreement in cases of circumferencial and mixed BE and not significant agreement for finger-like BE. ECE sensitivity and accuracy for detecting hiatal hernia were, respectively, 43 % and 74%, and fair agreement (kappa = 0.38) with MB chromoendoscopy. There was no statistical difference between the discomfort of examinations and there was no complication in both endoscopic methods. CONCLUSIONS: The ECE has proved to be a good method for detecting suspicious lesions of esophageal cancer. As the evaluation of the extent and pattern of BE, the ECE had reasonable results, when compared to MB chromoendoscopy. The ECE had unsatisfactory results regarding the detection of hiatal hernia. There was no significant difference in discomfort between the ECE and GIE. Both methods proved to be safe

No description available.

Many landing sites of scientific interest on Mars including most of the Southern Hemisphere at elevations above 2km Mars Orbiter Laser Altimeter reference are inaccessible due to current limitations in precision entry guidance and payload deceleration. Precision guidance and large payload deceleration is challenging due to the thin Martian atmosphere, large changes in free stream conditions during entry, and aerothermal and aerodynamic instability concerns associated with control systems with direct external flow field interaction. Such risks have descoped past Mars missions to unguided entry with the exception of Mars Science Laboratory's (MSL) bank angle guidance. Consequently, prior to MSL landing ellipses were on the order of 100's of km. MSL has approached the upper limit of payload deceleration capability for rigid, blunt body sphere cone aeroshells used on all successful Mars entry missions. Hypersonic Inflatable Aerodynamic Decelerators (HIADS) are in development for larger payload deceleration capability through inflated aeroshell diameters greater than rigid aeroshells constrained by the launch rocket diameter, but to date there has been limited dynamics, control, and guidance development for their use on future missions. This dissertation develops internal moving mass actuator (IMMA) control systems for improving Mars precision entry guidance of rigid capsules and demonstrating precision guidance capability for HIADs. IMMAs provide vehicle control moments without direct interaction with the external flow field and can increase payload mass delivered through reducing propellant mass for control and using portions of the payload for the IMMAs. Dynamics models for entry vehicles with rotation and translation IMMAs are developed. IMMA control systems using the models are developed for two NASA vehicle types: a 2.65 m, 602 kg Mars Phoenix-sized entry capsule and an 8.3 m, 5.9 metric ton HIAD approaching payload requirements for robotic precursor missions for future human missions. Linear Quadratic controllers with integral action for guidance command tracking are developed for translation and rotation IMMA configurations. Angle of attack and sideslip guidance laws are developed as an alternative to bank angle guidance for decoupling range and cross-range control for improved precision entry guidance. A new variant of the Apollo Earth return terminal guidance algorithm is implemented to provide the closed-loop angle of attack range control commands. Nonlinear simulations of the entire 8 degree of freedom closed-loop systems demonstrate precision guidance to nominal trajectories and final targets for off-nominal initial entry conditions for flight path angle, range, cross-range, speed and attitude. Mechanical power studies for IMMA motion show rotation IMMA require less total mechanical power than translation actuators, but both systems have low nominal mechanical power requirements (below 100 Watts). Precision guidance for both systems to terminal targets greater than 38 km down-range from an open-loop ballistic entry is shown for low mechanical power, low CM displacement, (< 4.5 in) and at low internal velocities (< 2 in/s) over significant dynamic pressure changes. The collective precision guidance results and low mechanical power requirements show IMMA based entry guidance control systems constitute a promising alternative to thruster based control systems for future Mars landers. / Ph. D.

Mixed association of calix[4]resorcinarene with ethyl sulfonate groups on the lower rim and dimethylaminomethyl groups on the upper rim (CR) and cationic surfactant 4-aza-1-hexadecyl-azoniabicyclo[2.2.2]octane bromide (DABCO-16) is studied by methods of tensiometry, conductometry, potentiometry and NMR spectroscopy at fixed CR concentration and varied surfactant concentration. Beyond ca. 0.4 mM of DABCO-16, mixed aggregates enriched by CR are proved to be formed due to electrostatic forces, while beyond ca. 5 mM, aggregates enriched by surfactant occur due to the hydrophobic effect. Spectrophotometry monitoring of the solubilization of a hydrophobic dye, Orange OT, demonstrated that only the second type of mixed aggregate enriched by DABCO-16 is capable of binding the organic probe, while the mixed system where the surfactant is a minor component shows no binding capacity towards Orange OT. This finding can be used for the design of nanocontainers with controllable binding/release properties. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Une capsule est une goutte de liquide enveloppée par une membrane fine et déformable. Les propriétés mécaniques de la membrane sont essentielles pour le mouvement de la capsule. L’analyse de l’écoulement d’une suspension de capsules dans un canal microfluidique au moyen d’un modèle mécanique est une technique permettant de déterminer les propriétés élastiques de la membrane. Un modèle numérique tridimensionnel a été développé pour résoudre ce problème d’interaction fluide-structure en écoulement confiné. Il couple une méthode des intégrales de frontières pour les écoulements des fluides et une méthode éléments finis pour la déformation de la membrane. Le modèle est utilisé pour étudier l’écoulement d’une capsule initialement sphérique dans des canaux de différentes sections. Dans un canal cylindrique, on montre que l’effet de confinement du canal conduit à la compression de la capsule. Cela engendre la formation de plis sur la membrane autour de l’axe de l’écoulement, phénomène également observé expérimentalement. Dans un canal de section carrée, les effets de la loi constitutive de la membrane, du rapport de taille et du débit d’écoulement sur la déformation de la capsule sont systématiquement étudiés. La comparaison entre les résultats expérimentaux et numériques nous permet de déduire les propriétés mécaniques de la membrane d’une population de capsules artificielles. Ce travail démontre la faisabilité de la mesure de propriétés mécaniques d’une membrane en utilisant une technique microfluidique en canal carré. Il pourrait être étendu par l’étude d’écoulements instationnaires dans un canal de section variable ou avec bifurcations. / A capsule is a liquid droplet enclosed by a thin and deformable membrane. The membrane mechanical properties are critical for the deformation and motion of capsules. The flow of a capsule suspension through a microfluidic channel with dimensions comparable to those of the suspended particles can be used to infer the membrane elastic properties. However a mechanical model of the process is necessary. We present a three-dimensional numerical model to simulate such fluid-structure interaction problem. We use a novel numerical model that couples a boundary integral method for the internal and external fluid flows and a finite element method for the membrane deformation. The model is applied to study the flow of an initially spherical capsule in channels with different cross-sections. In a cylindrical channel with circular cross-section, we show that the confinement effect leads to the compression of the capsule in the hoop direction. The membrane tends to buckle and to fold as observed experimentally. In a microfluidic channel with a square cross-section, the effects of the membrane constitutive law, size ratio and flow strength on the capsule deformation are systematically studied. The comparison between experimental and numerical results allows us to deduce the membrane mechanical properties of a population of artificial capsules. The present work shows that it is possible to measure the membrane mechanical properties by using a microfluidic channel with a square cross-section. It can be extended to unsteady capsule flows in a channel with variable cross-sections or bifurcations.