Thesis (M.S.)--Montana State University--Bozeman, 2007. / Typescript. Chairperson, Graduate Committee: Daniel P. Heil. Includes bibliographical references (leaves 50-54).

Thesis (M.S.)--University of Wisconsin--Madison, 1984. / Typescript. Title from title screen (viewed May 2, 2007). Includes bibliographical references (leaves 228-246). Online version of the print original.

Thesis (M.S.)--Oregon State University, 1985. / Typescript (photocopy). Includes bibliographical references (leaves 69-71). Also available on the World Wide Web.

No description available.

Th. doct.-ing.--Métal.--Grenoble--I.N.P.G., 1984. N°: DI 485.

No description available.

Fatigue is a major disabling symptom in patients with rheumatic disorders such as RA and GPA. This work was carried out to investigate whether macro/microstructural changes are associated with the presence and severity of fatigue in patients with RA. We obtained T1, diffusion tensor and magnetisation transfer magnetic resonance scans from a group of 60 patients with RA (30 with active disease and 30 with inactive disease) at baseline and follow-up scans in addition to 14 patients with GPA, 14 matched fatigue controls FC and 20 healthy controls HC. No significant differences in a range of volumetric qMRI, DTI or MTI measures were found between RA active and non-active patients. Volumetric data analysis revealed that subcortical GM change in volume is related to fatigue irrespective of whether patients had RA or GPA. Moreover, longitudinal findings in patients with RA whose fatigue levels improved between the two scanning sessions indicate that, firstly, white matter microstructural abnormalities occur in the neuronal circuitry connecting bilaterally the striatal and cortical regions. Secondly, there is an imbalance in limbic-thalamic-cortical circuit connecting basal ganglia with limbic system of the improver group. Finally, demyelination of either neural circuit to the facilitator afferent vagus nerve could contribute to fatigue in this patient cohort. Fatigue-related RA does not appear to be related to disease activity or sleep disturbance and might therefore be related to other factors such as pain or depression status. Reductions in the myelin integrity as detected by the MTR in RA fatigue patients overlapped with those detected with the DTI analysis, especially in the cerebellar connections, corona radiata, corpus callosum, fornix, corticospinal tract and right cingulum suggesting that brain volumes, FA and MTR measures might be potential biomarkers of fatigue-related RA.

La présence de carrières souterraines abandonnées dans le nord de la France, à proximité de zones urbanisées, est à l’origine de problèmes importants touchant à la sécurité des personnes et des constructions, d’une part, et à l’élaboration de plans d’urbanisme d’autre part. Dans ce cadre, cette thèse présente une étude numérique de comportement mécanique et stabilité de carrières souterraines creusées il y a longtemps dans la craie du nord de la France. Elle a pour objectif de proposer une approche complémentaire aux observations et investigations naturalistes. Ces dernières confirment la présence de familles des joints stratifiées dans la craie du nord de la France et d’autres fractures qui se développent due à la dégradation. Ainsi, le premier objectif est de rendre compte du comportement anisotrope induit par la présence de ces joints. Un critère de rupture orienté est développé et différents mécanismes de plasticité sont considérés pour générer cet effet. Une modélisation numérique tridimensionnelle d’une excavation est mise en œuvre. Une procédure de réduction des paramètres de résistance au cisaillement est proposée pour les joints afin d’étudier leur influence sur les mécanismes de déformation et de rupture et sur la stabilité. Les effets du temps et les mécanismes de dégradation induits par différents facteurs aggravants ont aussi un rôle important. Une approche de dégradation dépendante du temps a été développée pour l’analyse des mécanismes de déformation et de rupture en fonction du temps et pour l’estimation de la stabilité à long terme. Enfin, pour l’estimation préliminaire de la stabilité des carrières, des formules empiriques et des abaques sont proposés. / The presence of unexploited underground cavities in the region of North France regarding their close proximity to urbanized areas, poses serious problems in terms of security of both people and constructions on one hand, and induces a strong constraint against the planning and urban development on the other hand. In this framework, this thesis presents a numerical study of the mechanical behaviour and the long term stability of underground cavities excavated in the chalk substratum of North France. It aims to provide a complementary understanding to geological investigations and observations carried out. This latter shows that stratified joints are present in the chalk layers as well as fractures developing due to the degradation of chalk with time. Hence, the first target is to account for the anisotropic behaviour induced due to the presence of these joints. An oriented yield criterion is developed where several mechanisms of plasticity are considered to generate this effect. A three dimensional numerical model of the excavation is executed. An approach for reducing shear strength properties of the joints is proposed to study the joints influence on the strain and failure mechanisms and on the stability state of the cavity. Degradation mechanisms induced upon time in the presence of different aggravating factors create also a critical effect. A non-homogeneous time-dependent-degradation model is developed to analyse the time-dependent deformation and failure mechanisms and to assess the long term stability of these cavities. At the end, empirical formulae and abacuses are developed for a preliminary estimation of the stability of underground cavities of North France.

No description available.

The structure and physiology of synovial joints has been studied for years. Recent advances in technology and investigative tools have enabled workers to greatly elucidate the nature of these remarkably functional joints. This thesis presents a review of the literature dealing with the morphology and physiology of diarthrodial joints. The embryological development and the gross structure of these joints is presented as is a discussion of the light and electron microscopic features of articular cartilage and synovial membrane. In addition, some of the features of synovial fluid are presented. The results of recent investigation into the biochemistry and metabolism of articular cartilage are discussed. As the main function of synovial joints is to provide painless, controlled motion, much interest has recently focused on the mechanism of lubrication in these joints. A review of the literature concerning the nature of joint lubrication is presented, and a theory of lubrication enhancement by electrical repulsive forces is proposed. This theory was developed from the results of a technique of synovianalysis conducted on a series of 61 samples of synovial fluid. The samples were collected from a series of hospital patients. One group of patients suffered from rheumatoid arthritis, while a second group was comprised of patients suffering from conditions not associated with rheumatoid arthritis. The samples were subjected to analysis using cation sensitive glass electrodes, and the concentrations of ionized sodium and potassium were measured. In addition, sodium and potassium concentrations were measured in the synovial fluid samples using a spectrophotometer. As a result of these investigations, it was found that the synovial fluid samples from patients with rheumatoid arthritis contained a significantly lower concentration of ionized sodium. It is concluded that the lower concentration of sodium ions in synovial fluid of rheumatoid arthritis may result in a diminution of electrical repulsive forces acting within synovial joints, and explain, in part, the cartilage attrition seen in this disease. / Science, Faculty of / Botany, Department of / Zoology, Department of / Graduate