The sciatic nerve is the largest nerve in the human body giving both motor and sensory innervations to the lower limb. It can be affected in chronic diseases, such as diabetes, or compressed anatomically by structures such as piriformis and aneurysms leading to sciatica or paralysis of the lower limb. The current study therefore focuses on the arterial supply of the sciatic nerve as well as its course. Embryologically, the sciatic nerve is supplied via the axial artery during the first trimester. As the axial artery regresses, the iliac system develops. A failure of sciatic artery regression leads to several variations of pelvic and femoral arteries, with a risk of iatrogenic injury/trauma for those patients undergoing pelvic, gluteal and thigh surgical procedures. An understanding of the variability of the pelvic arteries in relation to a coexistent sciatic artery will provide an appropriate background for clinicians. The present study proposes a new theory of sciatic artery development and persistence, as well as new theories for the superior and inferior gluteal, internal pudendal and obturator arteries. The thesis is in two parts: first an anatomical study on the dissection of 171 cadavers including the pelvic, gluteal and thigh regions to observe (i) the patterns of the arteries these regions, and (ii) the course of the sciatic nerve. With variable course of sciatic nerve, there is a variability of its blood supply. Moreover, it includes a new classification of sciatic nerve with respect to clinical implications. The thesis clarifies the origins of the sciatic artery and its course. The second part is a literature review of sciatic artery aneurysm cases in 171 patients, which clarifies the risk of aneurysm, together with its incidence with respect to pathologic finding and associated disorders. Radiologists have to be aware of the internal iliac artery classifications to be able to alert general surgeons, orthopaedic surgeons, obstetricians, gynecologists, and urologists so that they can improve patient management.

Ce travail concerne l'étude de molécules d'ADN avec un microscope à force atomique utilisé<br />en « contact intermittent ». L'objectif poursuivi est de réaliser des mesures locales d'interaction et de<br />mécanique sur une chaîne d'ADN. Le microscope est sensible aux forces d'interaction entre une pointe<br />de dimension nanométrique et l'objet ou la surface à analyser. En mode dynamique, la pointe oscille au<br />voisinage de la surface à des fréquences de quelques centaines de kilohertz et des amplitudes de l'ordre<br />de la dizaine de nanomètres. Ce comportement peut devenir non-linéaire selon l'intensité de<br />l'interaction et des conditions d'oscillation. Varier ces conditions en termes d'amplitude ou de<br />fréquence constitue une opportunité de contrôler cette interaction. Nous mettons ainsi en évidence la<br />possibilité d'imager une seule molécule d'ADN selon différents modes d'interaction : pur attractif, pur<br />répulsif et un mélange des deux. Par ailleurs, le microscope de force dynamique n'est pleinement<br />efficace que dans le cadre de la maîtrise de l'interaction de la pointe avec l'objet. La qualité de<br />l'échantillon et celle de la pointe doivent être contrôlées à l'échelle des mesures. Des expériences<br />préliminaires ont amené à retenir des substrats de silice greffés avec des molécules de silanes.<br />Concernant les molécules d'ADN, trois types de séquences ont été étudiés. Une longue chaîne de 2500<br />paires de bases (pb) comportant une succession de séquences non périodique, une séquence de 450pb<br />constituée d'Adénine sur un mono-brin et de Thymine sur le brin complémentaire et une chaîne de<br />même longueur, mais constituée d'une alternance d'Adénine et de Thymine sur chaque mono-brin. Ces<br />échantillons sont intéressants par la diversité des caractéristiques mécaniques attendues. L'exploitation<br />expérimentale des différents régimes permet de révéler des informations géométriques, mécaniques et<br />physico-chimiques sur les conformations des molécules.

Ce travail concerne l'étude de molécules d'ADN avec un microscope à force atomique utilisé en « contact intermittent ». L'objectif poursuivi est de réaliser des mesures locales d'interaction et de mécanique sur une chaîne d'ADN. Le microscope est sensible aux forces d'interaction entre une pointe de dimension nanométrique et l'objet ou la surface à analyser. En mode dynamique, la pointe oscille au voisinage de la surface à des fréquences de quelques centaines de kilohertz et des amplitudes de l'ordre de la dizaine de nanomètres. Ce comportement peut devenir non-linéaire selon l'intensité de l'interaction et des conditions d'oscillation. Varier ces conditions en termes d'amplitude ou de fréquence constitue une opportunité de contrôler cette interaction. Nous mettons ainsi en évidence la possibilité d'imager une seule molécule d'ADN selon différents modes d'interaction : pur attractif, pur répulsif et un mélange des deux. Par ailleurs, le microscope de force dynamique n'est pleinement efficace que dans le cadre de la maîtrise de l'interaction de la pointe avec l'objet. La qualité de l'échantillon et celle de la pointe doivent être contrôlées à l'échelle des mesures. Des expériences préliminaires ont amené à retenir des substrats de silice greffés avec des molécules de silanes. Concernant les molécules d'ADN, trois types de séquences ont été étudiés. Une longue chaîne de 2500 paires de bases (pb) comportant une succession de séquences non périodique, une séquence de 450pb constituée d'Adénine sur un mono-brin et de Thymine sur le brin complémentaire et une chaîne de même longueur, mais constituée d'une alternance d'Adénine et de Thymine sur chaque mono-brin. Ces échantillons sont intéressants par la diversité des caractéristiques mécaniques attendues. L'exploitation expérimentale des différents régimes permet de révéler des informations géométriques, mécaniques et physico-chimiques sur les conformations des molécules.

Equi-caloric bouts of interval (INT: 5x 2:2 min at 85 and 40% VO2max) and continuous (21 minutes at 60% VO2max) exercise were performed by 13 older prehypertensive males on separate days, at equivalent times of day, to assess the influence of exercise mode on post-exercise hypotension (PEH). Cardiovascular measures were collected for 30 min pre and 60 min post-exercise. PEH as measured by mean post-exercise systolic blood pressure (SBP) decrease, area under the SBP curve, and minimum SBP achieved, was equivalent after both conditions. SV was significantly reduced and HR was significantly elevated post-exercise after both conditions. No significant reductions in CO or TPR were observed. INT exercise provided a larger perturbation to the autonomic nervous system as measured by Baroreflex sensitivity and Heart Rate Variability. The responses elicited by acute INT exercise, with repeated exposure, may lead to greater improvements in blood pressure regulation than those associated with continuous aerobic training.

Equi-caloric bouts of interval (INT: 5x 2:2 min at 85 and 40% VO2max) and continuous (21 minutes at 60% VO2max) exercise were performed by 13 older prehypertensive males on separate days, at equivalent times of day, to assess the influence of exercise mode on post-exercise hypotension (PEH). Cardiovascular measures were collected for 30 min pre and 60 min post-exercise. PEH as measured by mean post-exercise systolic blood pressure (SBP) decrease, area under the SBP curve, and minimum SBP achieved, was equivalent after both conditions. SV was significantly reduced and HR was significantly elevated post-exercise after both conditions. No significant reductions in CO or TPR were observed. INT exercise provided a larger perturbation to the autonomic nervous system as measured by Baroreflex sensitivity and Heart Rate Variability. The responses elicited by acute INT exercise, with repeated exposure, may lead to greater improvements in blood pressure regulation than those associated with continuous aerobic training.

The longitudinal feature of measurements and counting process of responses motivate the regression models for longitudinal count data (LCD) to take into account the phenomenons such as within-subject association and overdispersion. One common problem in longitudinal studies is the missing data problem, which adds additional difficulties into the analysis. The missingness can be handled with missing data techniques. However, the amount of missingness in the data and the missingness mechanism that the data have affect the performance of missing data techniques. In this thesis, among the regression models for LCD, the Log-Log-Gamma marginalized multilevel model (Log-Log-Gamma MMM) and the random-intercept model are focused on. The performance of the models is compared via a simulation study under three missing data mechanisms (missing completely at random, missing at random conditional on observed data, and missing not random), two types of missingness percentage (10% and 20%), and four missing data techniques (complete case analysis, subject, occasion and conditional mean imputation). The simulation study shows that while the mean absolute error and mean square error values of Log-Log-Gamma MMM are larger in amount compared to the random-intercept model, both regression models yield parallel results. The simulation study results justify that the amount of missingness in the data and that the missingness mechanism that the data have, strictly influence the performance of missing data techniques under both regression models. Furthermore, while generally occasion mean imputation displays the worst performance, conditional mean imputation shows a superior performance over occasion and subject mean imputation and gives parallel results with complete case analysis.

The purpose of this study was to determine the effects of 4 week respiratory muscle training (RMT) on intermittent recovery performance, pulmonary functions and maximum oxygen consumption capacity (Vo2max) of young soccer players. Eighteen young soccer player who were playing in the Turkey PAF League (league for candidate professional soccer players) from Hacettepe Sports Club with a mean age of 18.4 &plusmn / 0.8 years (ranging from 17 to 19 years) and 8.5 &plusmn / 0.7 (ranging from 7 to 9 years) years experience in soccer participated. Players&rsquo / weekly metabolic equivalent score (MET) was 120. Their maximum oxygen consumption (Vo2max) on a treadmill, pulmonary function with a spirometer, and recovery performance with a yo-yo intermittent recovery test level 2 were measured and then they were randomly assigned into two groups as either RMT (n = 9) or control (n = 9). The RMT group continued both their regular training and RMT treatment with a commercially available powerlung sport respiratory muscle trainer (Powerlung Inc., TX, and USA) for 4 weeks. The control group only continued with their regular training. After completing 4 week RMT implementation (composed of 30 sets of inhalation, two times a day, 5 days of the week), the same tests were performed in order to see the v effects of 4 week RMT treatment on selected parameters mentioned above. Findings of this study indicated that 4 week of RMT treatment significantly improved (% 39) yo-yo intermittent recovery test level 2 performances of the RMT group from pre to post test measurements when compared to subjects in the control group. However, there were no significant improvements in both RMT and control group&rsquo / s Vo2max capacity, Vital capacity (VC), Forced vital capacity (FVC), forced expiratory flow (FEV1.0) and Peak expiratory flow performances (PEF). As a conclusion, 4 week of RMT implementation improves the intermittent recovery performance of young soccer players.

In der vorliegenden Arbeit wird die Entwicklung von ausschließlich elektrostatisch arbeitenden Sensor-Aktor-Arrays zur Oberflächenprofilbestimmung an Mikroteilen beschrieben. Ein wesentliches Merkmal der Strukturen ist ihr großer Eigenzustellbereich von bis zu 20 Mikrometer. Die Auswertung atomarer Kräfte ermöglicht Wegauflösungen im Nanometerbereich. Auf Grund der geringen Abmessungen durch die mikromechanische Fertigung des Sensorelements und der integrierten Sensor-Aktorfunktion sind Anordnungen als Zeilenarray möglich. Die Entwicklung richtet sich auf Strukturen, welche in klassischer Oberflächentechnologie gefertigt werden können. Durchgeführte experimentelle Tests wurden mit Sensoren in Silizium-bulk-Mikromechanik (SCREAM) realisiert. Der Schwerpunkt der Arbeit behandelt die Charakterisierung der Sensorelemente und damit verbundene Layoutverbesserungen, wie das Einbringen von Feldstoppern und die Nutzbarkeit des Sensors zur Profilbestimmung von Oberflächen unter Beachtung industrieller Anforderungen. Vorteile des Einsatzes eines solchen Sensor-Aktor-Arrays liegen in der Miniaturisierung und dem vergleichsweise großen Eigenzustellbereich jedes einzelnen Sensors. Dadurch ist es möglich, technische Oberflächen, welche im Eigenzustellbereich des Sensorarrays liegen, ohne das Nachregeln einer übergeordneten Positioniereinheit im Profil zu bestimmen. Es wird gezeigt, wie die angewandte kapazitive Wirkungsweise des Sensors mit den sehr kleinen Nutzkapazitäten im Beisein von großen Parasitärkapazitäten zur Signalauswertung genutzt werden kann.

Alcohol use disorder is a worldwide public health problem and is a disorder with substantial individual variation. There are suggested links between various behavioral traits, comorbid psychiatric diseases and excessive alcohol consumption. Moreover, the endogenous opioid system is involved in alcohol reward and reinforcement, and implicated in the action of alcohol. However, less is known about the complex associations between individual differences in behavior, alcohol consumption, pharmacotherapy response and related neurochemical mechanisms. Experimental animal models are critical for understanding the neurobiological underpinnings of alcohol use disorder. The overall aims of this thesis were: i) to study the association between behavior and voluntary alcohol intake in outbred rats; ii) to study the association of voluntary alcohol intake, behavior, opioid receptor density and response to naltrexone; and iii) to obtain detailed behavioral characterizations of the animals on the basis of their voluntary alcohol intake. The results revealed that the multivariate concentric square fieldTM (MCSF) test was a complementary method for understanding mechanisms underlying various mental states. The MCSF broadened the perspective on risk-related behaviors, including aspects of risk assessment. Individual differences in alcohol intake using the modified intermittent access paradigm enabled analyses of drinking patterns in high and low alcohol-drinking rats. There was an alcohol deprivation effect in high-drinking animals only. The behavior profiling of high alcohol drinking- rats before and after alcohol access suggested that this subgroup was consuming alcohol for its anxiolytic properties. Long-lasting changes were found in the mu and the delta opioid receptors after long-term, intermittent voluntary alcohol intake; some of these changes are in line with findings in humans. The voluntary alcohol consumption and the concomitant response to naltrexone were different for Wistar rats from different suppliers. Moreover, the Rcc Wistar rats may be more suitable for studies of alcohol use disorders due to increasing alcohol intake and the presence of a high-drinking subpopulation with increasing alcohol intake over time. The high-drinking subpopulation showed pronounced effects of naltrexone on alcohol intake. In conclusion, studies of individual differences increase understanding of variability in behavior, pharmacotherapy response and factors involved in vulnerability of alcohol use disorders.

This dissertation develops a general framework for designing stabilizing feedback controllers and observers for dynamics with state/time dependent gains on the control signals and measured outputs. These gains have potential singularity periods but satisfy a technically non-trivial condition referred to as persistence of excitation. A persistence filter design constitutes the primary theoretical innovation of this work around which the controller and observer development is centered. Application areas of singular gain systems considered in this study include robotics, biomechanics, intelligent structures and spacecrafts. Several representative problems involving singular, time-dependent gains are addressed. The specific contributions of this dissertation are outlined as follows: (i) a stabilizing feedback for linear, single-input systems with time-varying, singular control scaling is designed that allows arbitrary exponential convergence rate for the closed-loop dynamics. An adaptive control generalization of this result allows asymptotic convergence in presence of unknown plant parameters. An extension to a special, single-input nonlinear system in the controller canonical form is also proposed. It is proven that this control design results in bounded tracking error signals for a trajectory tracking objective; (ii) observer design for linear, single-output systems with time-varying, singular measurement gains is considered. A persistence filter similar in structure to the control counterpart aids an observer design that guarantees exponential state reconstruction with arbitrary convergence rates; (iii) the observer and controller designs are combined to obtain an exponentially stabilizing output feedback controller for linear, single-input, single-output dynamics with singular gains on both the control and measurements. A novel separation property is established as a consequence. The construction motivates applications to stabilization with reversible transducers which can switch between sensor and actuator modes. The results are verified on two illustrative applications, vibration control using piezoelectric devices and inverted pendulum stabilization with a DC motor. The linear result is further generalized to include state dependent gains; (iv) application of the persistence filter theory to spacecraft attitude stabilization using intermittent actuation is explored. The intermittence is characterized by a time-varying, periodically singular control gain. A nonlinear persistence filter allows construction of an exponentially stabilizing controller and simulations verify convergence with intermittent actuation where conventional proportional-derivative control fails; (v) a stabilization result for a special multi-input, linear system with time-varying matrix control gains is presented. The matrix gain is assumed to be diagonal but allows fewer controls than states subject to a controllability assumption in absence of the singular gain matrix. The single-input adaptive control results are shown to extend to the multi-input case. An application to angular velocity stabilization of an underactuated rigid spacecraft is considered. / text