68 research outputs found
Analysis of the kinetics of the parathyroid hormone, and of associated patient outcomes, in a cohort of haemodialysis patients
De la pluie à l'eau souterraine (apport du traçage naturel (ions majeurs, isotopes) à l'étude du fonctionnement des aquifères volcaniques (bassin d'Argnat, Auvergne, France))
Les propriétés hydrogéologiques de la Chaîne des Puys sont liées à ses particularités climatiques, géologiques, morphologiques et environnementales qui vont contraindre l'eau souterraine en terme d'origines quantité qualité et parcours dans les aquifères volcaniques. Lacomposition chimique et isotopique de l'eau reflétant l'ensemble des processus intervenant lors du cycle de l'eau, ses variations au sein et entre les différents compartiments permettent donc de préciser le rôle de ces différents facteurs . La caractérisation chimique (ions majeurs) et isotopiques (d18O, d2H, d13C) des différentes étapes du cycle de l'eau peut donc permettre de préciser le fonctionnement des aquifères de la Chaîne des Puys. Dans cette perspective, notre travail s'est articulé autour de deuxthèmes: 1) la définition du signal d'entrée des aquifères régionaux, préalable indispensable à toute hydrogéologique, 2) l'étude du fonctionnement du bassin d'Argnat localisé au Nord de la Chaîne des Puys.CLERMONT FD-BCIU Sci.et Tech. (630142101) / SudocSudocFranceF
Intérêts et limites de l’Hémodialyse Longue Nocturne
Intermittent long nocturnal hemodialysis (LNHD) combines dialysis and sleep. Its clinical advantages are a reduced ultrafiltration rate, better control of blood volume with improved tolerance of the sessions and cardiac performance, better clearance of phosphates and middle molecules, and better survival in cohort studies. Quality of life is not impaired by the length of the sessions and, when not optimal, improves when transferring from standard hemodialysis (HD) to LNHD. The quality of sleep is sometimes disturbed, but it is not an important cause of exit from the program. The sustainability of an LNHD program depends on the joint medical and managerial will, the selection of stable patients, respect for schedules, and the duration of sessions, which is essential for sleep dialysis. The health authorities must play a role in allowing this modality under acceptable financial conditions. Informing the patient of the existence of LNHD before the dialysis stage is essential, helped by the testimony of peers. Learned societies should support research and the provision of information to nephrologists. Finally, architectural conditions that promote privacy and sleep are key to the success of the program.L’hémodialyse (HD) Longue Nocturne (HDLN) intermittente permet de combiner dialyse et sommeil. Ses avantages cliniques sont une vitesse d’ultrafiltration réduite, un meilleur contrôle de la volémie avec amélioration de la tolérance des séances et des performances cardiaques, une phosphatémie et des moyennes molécules mieux épurées et une meilleure survie dans les études de cohortes. La qualité de vie n’est pas altérée par la longueur des séances et elle s’améliore quand elle n’est pas optimale lors du transfert de l’HD standard vers l’HDLN. La qualité du sommeil n’est parfois perturbée mais elle n’est pas une cause importante de sortie du programme. La pérennité d’un programme d’HDLN passe par les volontés conjointes médicales et managériales, la sélection des patients stables, le respect des horaires et de la durée de séances, indispensable à la dialyse de sommeil. Les autorités de santé doivent jouer un rôle pour permettre cette modalité dans des conditions financières acceptables. L’information au patient de l’existence de l’HDLN avant le stade de la dialyse est essentielle, aidée par le témoignage des pairs. Les sociétés savantes doivent soutenir la recherche et l’information aux néphrologues. Enfin les conditions architecturales favorisant l’intimité et le sommeil sont une clé de réussite du programme
Vitamin D in Chronic Kidney Disease and Dialysis Patients
Vitamin D deficiency (<20 ng/mL) and insufficiency (20–29 ng/mL) are common among patients with chronic kidney disease (CKD) or undergoing dialysis. In addition to nutritional and sunlight exposure deficits, factors that affect vitamin D deficiency include race, sex, age, obesity and impaired vitamin D synthesis and metabolism. Serum 1,25(OH)2D levels also decrease progressively because of 25(OH)D deficiency, together with impaired availability of 25(OH)D by renal proximal tubular cells, high fibroblast growth factor (FGF)-23 and decreased functional renal tissue. As in the general population, this condition is associated with increased morbidity and poor outcomes. Together with the progressive decline of serum calcitriol, vitamin D deficiency leads to secondary hyperparathyroidism (SHPT) and its complications, tertiary hyperparathyroidism and hypercalcemia, which require surgical parathyroidectomy or calcimimetics. Kidney Disease Outcomes Quality Initiative (KDOQI) and Kidney Disease Improving Global Outcomes (KDIGO) experts have recognized that vitamin D insufficiency and deficiency should be avoided in CKD and dialysis patients by using supplementation to prevent SHPT. Many vitamin D supplementation regimens using either ergocalciferol or cholecalciferol daily, weekly or monthly have been reported. The benefit of native vitamin D supplementation remains debatable because observational studies suggest that vitamin D receptor activator (VDRA) use is associated with better outcomes and it is more efficient for decreasing the serum parathormone (PTH) levels. Vitamin D has pleiotropic effects on the immune, cardiovascular and neurological systems and on antineoplastic activity. Extra-renal organs possess the enzymatic capacity to convert 25(OH)D to 1,25(OH)2D. Despite many unanswered questions, much data support vitamin D use in renal patients. This article emphasizes the role of native vitamin D replacement during all-phases of CKD together with VDRA when SHPT persists
Flow characterization and boundary layer transition studies in {VKI} hypersonic facilities
info:eu-repo/semantics/publishe
Hypersonic aerodynamics of a free-flying ring interfering with a two-dimensional curved shock wave - ATD3 test case
Optical characterization of boundary layer transition in hypersonic flows
info:eu-repo/semantics/publishe
Six Degrees of Freedom Free-flight Measurement in the VKI Longshot Wind Tunnel
Free-flight testing methodologies have shown superior capabilities to aerodynamic balances for testing space debris and analyzing proximal body separation scenarios in short-duration hypersonic wind tunnels. A free-flight testing methodology has been established for the VKI Longshot wind tunnel previously, and the present paper discusses the advancements of the measurement setup and the post-processing algorithms to facilitate six degrees of freedom trajectory and aerodynamic analyses. A second, vertical optical view is implemented in addition to the horizontal schlieren visualization applied exclusively during previous experiments. The coupling of the two perspectives permits the measurement of the models' spanwise displacement and the computation of the aerodynamic coefficients along all axes. Experiments with simple spherical and cuboid geometries were performed for fine-tuning the processing algorithms. The dual camera setup and the upgraded tracking algorithms proved good capabilities for tracking the objects' motion and the measured aerodynamic forces presented a good agreement with former experimental data and empirical correlations
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