The hypothesis was tested that meditation using an audible word-sound would be superior to silent repetition of the same word in producing decrements in autonomic arousal and improvements in anxiety, mood, and the ability to cope with stress. The influence of hypnotic susceptibility upon improvement was also evaluated. Thirty subjects, assigned to one of three groups: audible meditation, silent meditation, and relaxation control, met one hour weekly for six weeks to practice their respective technique and discuss their progress. All subjects were evaluated using the Harvard Group Scale of Hypnotic Susceptibility, a medical symptom checklist, the Spielberger Trait Anxiety Scale, a self-rating of state anxiety, and factors C and Q4 of the 16PF. Finger temperature was taken as a measure of physiological arousal. Confidence ratings of the respective strategies were taken pre- and post-treatment.

Deux séries d'échantillon à base de PVDF ont été élaborées avec différentes fractions de dioxyde de titane TiO2 en utilisant deux modes d'élaboration : dispersion des nanoparticules de TiO2 par voie fondue habituelle et génération des charges de TiO2 basée sur des réactions d'hydrolyse-condensations d'un alkoxyde de titane (le n-tétrabutoxyde de titane). Dans cette étude, quatre techniques ont été utilisées pour étudier les processus de relaxation dans les polymères semi-cristallins. Le microscope électronique à balayage (MEB) pour étudier la dispersion des nanoparticules de TiO2 dans la matrice PVDF. La calorimétrie différentielle à balayage (DSC) a été utilisée dans cette étude pour caractériser thermiquement les échantillons polymériques semi-cristallins. L'analyse thermo-gravimétrique (ATG) a été utilisée pour voir l'effet de nanoparticules sur les propriétés thermiques du PVDF. De plus, la technique de spectroscopie diélectrique a été utilisée dans la thèse pour étudier l'influence du processus d'élaboration sur la mobilité moléculaire trouvée dans ces systèmes. On a montré que le comportement de ces nanocomposites est proche de celui de PVDF pur. Les changements principaux observés sont le ralentissement de la dynamique de la relaxation alpha (associée à la température de transition vitreuse) et la relaxation alpha c (associée à la phase cristalline) en fonction de l'augmentation de fraction volumique TiO2. L'existence des charges piégées aux interfaces qui met en cause la présence de la polarisation interfaciale (IP) dans les différents nanocomposites a aussi été analysée. Les additions de TiO2 diminuent la mobilité des chaînes polymériques ce qui rend difficile l'orientation des dipôles électriques et augmente l'énergie d'activation de la relaxation de polarisation interfaciale / Polyvinylidene fluoride (PVDF) films have been filled with different volume fraction of titanate dioxide TiO2 using two ways : dispersion in the melt or in-situ generation based on the hydrolysis-condensation reactions of titanium alkoxide inorganic precursor premixed with PVDF under molten conditions. In this study, four techniques were used to study the relaxation processes in the semi-crystalline polymers. The scanning electron microscope (SEM) was introduced in the field of polymer science to study the dispersion of TiO2 nanoparticules in the PVDF matrix. The differential scanning calorimetry (DSC) was used in this study to thermally characterize the semi-crystalline polymer samples. Thermal gravimetric analysis (TGA) was used to see the effect of nanoparticles on the thermal properties of PVDF. In addition, the dielectric spectroscopy technique was used in the thesis to study the influence of the process on the molecular mobility found in these systems. It was shown that the behavior of PVDF as a matrix in these nanocomposite is close to that of pure PVDF. The main changes observed is the slowing down of the dynamics of the alpha a (associated to the glass transition temperature) and the alpha c (associated to the crystalline phase) relaxations as a function of the TiO2 volume fraction increase. The existence of charge carriers trapping at the interfaces related to the interfacial polarization (IP) in the different nanocomposites has also been analyzed. The additions of TiO2 decrease the mobility of the polymer chains which makes difficult the orientation of electric dipole moment ending in an increase of the energy of activation of IP relaxation

Doctorat en kinésithérapie et réadaptation / info:eu-repo/semantics/nonPublished

In order to assess the relative efficacy of audio-taped relaxation as compared to live-therapist induced relaxation, 80 volunteer subjects were randomly assigned to one of the following eight groups: (1) live-therapist (male) contingent, (2) live-therapist (male) non-contingent, (3) taped contingent (male), (4) taped non-contingent (male), (5) live-therapist (female) contingent, (6) live-therapist (female) non-contingent, (7) taped (female) contingent, and (8) taped (female) non-contingent. The subjects were exposed to treatment conditions for five sessions during which they received a relaxation sequence via either a live-therapist or audio-taped format in a contingent or non-contingent (subject controlled pace or non-subject controlled pace, respectively) progression. The subjects were monitored with an EMG and Skin Temperature device for 10 minutes following the relaxation sequence. Following the relaxation sequence, each subject was administered a subjective relaxation scale. The first session data were compared to the last session data via a 4 way ANOVA at a .05 alpha level. The analysis of variance indicated that all groups on all of the dependent variables became more relaxed (EMG reduction and skin temperature increase) from pre to post period monitorings. On the variables of EMG and skin temperature, the live-therapist and contingent progression groups produced greater relaxation than did the taped and non-contingent groups. The combination of live-therapist and contingent progression proved to be the most effective in reducing EMG and increasing peripheral skin temperature. (Both indications of relaxation.) All the treatment groups responded similarly on verbal report with the live-therapist contingent and taped-therapist non-contingent groups decreasing most on the verbally reported subjective scale. Implications for the use of live and taped-therapist presentations along with contingent progression formats were discussed.

Pour améliorer la caractérisation et le dimensionnement des disques de turbines pour les moteurs d’avion, le motoriste Safran Aircraft Engines (SAE) développe des modèles de comportement, des lois d’endommagement et des critères de fatigue plus adaptés aux chargements réels. Pour aider à cette démarche, le but de cette étude est de développer un modèle de plasticité adapté à l'Inco718DA (un alliage à base nickel utilisé dans la fabrication des turbines haute pression), capable de représenter différents chargements (monotone, cyclique symétrique et non-symétrique). La proposition puis l'identification du modèle a été possible grâce à une campagne expérimentale favorisant des tests complexes et innovants aux essais de fatigue nombreux et coûteux. Les essais faits incluent un essai monotone avec décharges élastiques, un essai multi-niveau à Rε=-1 et deux essais multi-niveau à Rε=0 pour mieux caractériser la relaxation de la contrainte moyenne et un essai pour quantifer le rochet. Le comportement cyclique du matériau a été identifié en utilisant un écrouissage cinématique non saturant avec des éléments s'inspirant de la surface mémoire de Chaboche. Un des défis a été d'obtenir des boucles stabilisées "pointues" dans un régime de plasticité cyclique saturante, en utilisant une évolution du paramètre Γ en fonction de la déformation plastique équivalente maximale (prefacteur du terme de rappel de la loi d'écrouissage cinématique).Une deuxième difficulté apparaît dans la description de la relaxation de la contrainte moyenne, phénomène complexe avec un impact considérable sur la durée de vie en fatigue. Dans le chapitre 3, un modèle est proposé pour la caractérisation de la relaxation partielle de la contrainte moyenne. Une originalité du modèle est l'idée que la relaxation incomplète est une conséquence directe de la différence entre la charge et la décharge de la boucle de hystérésis. Le paramètre choisi pour décrire cette différence a été le préfacteur du terme de rappel Γ, pour lequel la thermodynamique donne de la liberté. Par rapport à d'autres lois d'écrouissage confirmées, notre modèle présente l'avantage d'utiliser un seul terme de rappel, mais avec une formulation plus complexe. En plus, le modèle est incrémental (écrit en taux/en vitesse), il peut donc prendre en compte des chargements complexes tels que aléatoires ou plus simplement tels que dans les essais multi-niveaux pilotés en déformation. Dans le dernier chapitre de la thèse, une campagne biaxiale vaste est présentée, avec les développements pour réaliser des essais biaxiaux pilotés en déformation. La campagne biaxiale a été réalisée sur des éprouvettes cruciformes en utilisant des capteurs LASER et des mesures de champs mono et stéréo analysées en utilisant la Corrélation d'Images Numeriques (CIN). Pour analyser la relaxation de la contrainte moyenne en biaxial un moyen de mesure et de contrôle fiable a dû être développé, adapté aux déformations plastiques élevées qui apparaissent dans la région d'intérêt de l'éprouvette. En utilisant la corrélation d'images intégrée (I-CIN) avec des fonctions de forme adaptées sur un seul élément et des calculs sur GPU, on a obtenu des fréquences de mesure de 100~Hz. En plus, avec sa précision et vitesse, I-CIN a été une technique adaptée pour contrôler une machine d'essais multiaxiale hydraulique. Un résultat important obtenu quand on a réalisé des essais equi-biaxiaux pilotés en déformation a été l'observation d'une relaxation de la contrainte moyenne très faible par rapport au cas uniaxial. Ce résultat doit être pris en compte dans les études futures avec des calculs éléments finis sur l'éprouvette complète. / To improve the characterization and design of aircraft engine turbine disks, the propulsion systems manufacturer Safran Aircraft Engines (SAE) develops constitutive equations, damage laws and fatigue criteria that are more adapted to real loadings. As part of this effort, the purpose of the current study is to develop a plasticity model for Inco718DA (a nickel-based alloy used in the manufacturing of high-pressure turbine disks), capable of representing several loading conditions (monotonic, symmetrical and non-symmetrical cyclic loading). The identification of the model was possible thanks to a uniaxial campaign, favoring a few but complex, innovative, tests to numerous costly fatigue tests. The tests we performed include a monotonic test with elastic discharges, a multi-level Rε = -1 test and two multi-level Rε = 0 tests that better quantify the mean stress relaxation and a test to identify ratcheting. The cyclic behavior was identified using a non-saturating kinematic hardening law with elements of Chaboche's memory surface. One of the challenges was to obtain sharp stabilized loops in a saturated cyclic plasticity regime, which was possible using parameter Γ evolving with respect to the maximum equivalent plastic strain, in the back-stress of kinematic hardening rule.A second difficulty appears in the description of mean stress relaxation, which has a considerable impact on fatigue lifetime. In chapter 3, a model is proposed for the description of the incomplete mean stress relaxation. One of the originalities is the idea that incomplete mean stress relaxation is a direct consequence of the difference between the loading and the unloading part of the hysteresis loop. The parameter we used to describe this difference, was the prefactor of the back-stress term Γ, for which the thermodynamics allows liberty. When compared to confirmed kinematic hardening laws that model non-zero mean stress relaxation, our model presents the advantage of using only one backstress, even if its description is more complex. Moreover, the model is incremental (written in a rate form in chapter 3 section 5) so it can take into account complex loadings such as multi-level strain-controlled tests.In the last chapter of the thesis, a vast biaxial campaign is presented, along with developments to make biaxial strain-controlled tests. The biaxial campaign was performed on cross-shaped samples using LASER sensors, mono and stereo full-field measurements using Digital Image Correlation (DIC). In order to analyze biaxial mean stress relaxation, a reliable measurement and control method had to be developed for the high plastic strains occurring in the region of interest of the sample. By using an Integrated-DIC (I-DIC) algorithm with adequate shape functions on one element and GPU computations we were able to obtain measurement frequencies of 100 Hz. Moreover, with its precision and speed, I-DIC proved to be a suitable technique for controlling a biaxial hydraulic machine. An important result obtained when performing equi-biaxial I-DIC strain-controlled tests was that there was very little biaxial mean stress relaxation, with respect to the uniaxial case. This result will have to be taken into account in future studies when performing finite element computations of the whole sample.

La frataxine est une protéine mitochondriale bien conservée de la bactérie à l’homme. La déficience de la frataxine chez l’homme entraine une maladie neurodégénérative grave, appelée Ataxie de Friedreich. Cette protéine a été découverte dans les années 90s et depuis sa fonction physiologique exacte n’est toujours pas connue. La frataxine joue un rôle important dans la biosynthèse des centres Fe-S dans l’homéostasie du fer et/ou dans la protection contre le stress oxydant. Dans cette thèse, nous nous intéressons aux interactions entre la protéine et d’autres molécules, comme certains métaux mitochondriaux ou protéines pour mieux comprendre la fonction de la frataxine dans la cellule. Lors de ce travail, la frataxine de levure (Yfh1) a été synthétisée par la technique de l’ADN recombinant, puis purifiée pour les études physico-chimiques. La flavohémoglobine (Yhb1)qui joue le rôle important dans la détoxification de NO (un agent du stress oxydatif et nitrosatif) a été aussi exprimée et purifiée selon le même principe. Ensuite, nous avons étudié la thermodynamique et la cinétique de la complexation de Yfh1 par les métaux mitochondriaux comme Fe, Cu, Mn, Zn, ainsi qu’avec les protéines impliquées dans le système antioxydant comme les superoxydes dismutases, CuZnSOD et MnSOD, et la flavohémoglobine. Ces résultats montrent tout d’abord que Yfh1 interagit avec tous les métaux mitochondriaux,néanmoins elle présente une meilleure affinité pour le cuivre et le manganèse. Par la suite, nous mettons en évidence le rôle remarquable de la frataxine dans le système antioxydant. Nous attribuons ainsi à la frataxine un rôle de protéine multifonctionnelle : « régulateur » dans le métabolisme des métaux. / The frataxin is a mitochondrial protein which is highly conserved during the evolution. The deficiency of frataxinin human induces a neurodegenerative disease: Friedreich’s ataxia. This protein was discovered in the nineties.However, its functions are always opened questions. It has been shown that frataxin participates in the assemblyof Fe-S cluster, as well as the iron homeostasis and cellular antioxidant system. The interactions between frataxinand others molecules, such as metals or proteins, are necessary for a better understanding of protein’s functions.In this work, we synthesized a yeast frataxin homologue (Yfh1) by DNA recombinant technique, and thenpurified it for cell free studies. Yeast flavohemoglobin (Yhb1), which is responsible for the detoxification of NO(an oxidative and nitrosative stress agent), was also isolated. We started by determining the thermodynamics andkinetics of the physiological interaction between Yfh1 and mitochondrial metals, such as Fe, Cu, Mn and Zn, aswell as the interaction with the gatekeepers in the anti-oxidative stress such as superoxide dismutases, CuZnSOD& MnSOD, and Yhb1. We underline here, in the first part the unspecific interaction of Yfh1 with mitochondrialmetals, and more especially the higher affinity of Yfh1 for copper and manganese than for iron. We also confirmthe remarkable participation of Yfh1 in the antioxidant system. Based on these observations, we assume thatfrataxin plays the role of a “regulator” in metal metabolism.

A psychological intervention involving relaxation training and biofeedback training for the control of peripheral skin temperature was investigated in this study with 27 female rheumatoid arthritics as participants. Based on analysis of the temperature data, it was concluded that the biofeedback response was not learned. From electromyographic data, it was concluded that participants did learn to relax. The hypothesis that the two treatment components would have beneficial effects on the physical, functional, and psychological aspects of rheumatoid arthritis was answered partially. No differential effects as a function of biofeedback training were found as the data for the temperature increase and temperature decrease groups were statistically combined in multiple analyses of variance for repeated measures. Although no differential effects were obtained, numerous positive changes were found. Correlated with the relaxation training were decreases in reported subjective units of discomfort, percentage of time hurting, percentage of body hurting, and general severity of pain. Improved sleep patterns were reported as was increased performance of activities of daily living. Reductions were also found in psychological tension, and in the amount of time mood was influenced by the disease. Shifts were not found in imagery, locus of control, and other psychological dimensions. Constitutional improvements were also absent.

The purpose of this investigation was to separate the effects, and determine the optimal and most feasible methods, of promoting skin temperature increase in a clinical prison population. There were no significant differences among the instructional sets with respect to skin temperature increase. Skin Temperature feedback significantly delayed the time of maximum temperature increase. However, the average delay of 3.5 minutes was not considered to be clinically significant. No other significant effects were evidenced from feedback training. It was suggested that the lack of differential effects among the instructional sets and feedback training may be a characteristic of the early stages of training and that significant differences might emerge if training were continued over a greater number of sessions.The question was raised as to whether skin-temperature training had taken place during the two training sessions. The subjects may have been displaying a nonspecific "relaxation response" or habituation to the experimental situation. It may take more than two sessions before significant conditioning of the skin-temperature response occurs. Recommendations for future research were specified, including an increase in the number of training sessions and the addition of new control procedures.

No description available.

No description available.