Functionals of the Brownian motion, localization and metric graphs

We review several results related to the problem of a quantum particle in a random environment. In an introductory part, we recall how several functionals of the Brownian motion arise in the study of electronic transport in weakly disordered metals (weak localization). Two aspects of the physics of the one-dimensional strong localization are reviewed : some properties of the scattering by a random potential (time delay distribution) and a study of the spectrum of a random potential on a bounded domain (the extreme value statistics of the eigenvalues). Then we mention several results concerning the diffusion on graphs, and more generally the spectral properties of the Schr\"odinger operator on graphs. The interest of spectral determinants as generating functions characterizing the diffusion on graphs is illustrated. Finally, we consider a two-dimensional model of a charged particle coupled to the random magnetic field due to magnetic vortices. We recall the connection between spectral properties of this model and winding functionals of the planar Brownian motion.Comment: Review article. 50 pages, 21 eps figures. Version 2: section 5.5 and conclusion added. Several references adde

B cell–intrinsic signaling through IL-21 receptor and STAT3 is required for establishing long-lived antibody responses in humans

Engagement of cytokine receptors by specific ligands activate Janus kinase–signal transducer and activator of transcription (STAT) signaling pathways. The exact roles of STATs in human lymphocyte behavior remain incompletely defined. Interleukin (IL)-21 activates STAT1 and STAT3 and has emerged as a potent regulator of B cell differentiation. We have studied patients with inactivating mutations in STAT1 or STAT3 to dissect their contribution to B cell function in vivo and in response to IL-21 in vitro. STAT3 mutations dramatically reduced the number of functional, antigen (Ag)-specific memory B cells and abolished the ability of IL-21 to induce naive B cells to differentiate into plasma cells (PCs). This resulted from impaired activation of the molecular machinery required for PC generation. In contrast, STAT1 deficiency had no effect on memory B cell formation in vivo or IL-21–induced immunoglobulin secretion in vitro. Thus, STAT3 plays a critical role in generating effector B cells from naive precursors in humans. STAT3-activating cytokines such as IL-21 thus underpin Ag-specific humoral immune responses and provide a mechanism for the functional antibody deficit in STAT3-deficient patients

Auguste Choisy. — Histoire de l'architecture. — Gauthier-Villars, 1899

Schopfer Jean. Auguste Choisy. — Histoire de l'architecture. — Gauthier-Villars, 1899. In: Revue internationale de l'enseignement, tome 37, Janvier-Juin 1899. pp. 569-570

Epidural sufentanil during paediatric cardiac surgery: effects on metabolic response and postoperative outcome

The metabolic and neuroendocrine effects of caudal epidural analgesia were studied during paediatric cardiac surgery. Combined epidural and general anaesthesia (EPI group; n=12) was compared with deep opioid anaesthesia (DOA group; n=12). During anaesthesia and surgery, haemodynamic stability was similar in the two groups. There was no significant difference between groups concerning the metabolic response to surgery but circulating catecholamines were significantly lower in the EPI group during and after surgery. Perioperative release of IL-6 was higher in the EPI group possibly reflecting a longer aortic clamp time. Incidence of postoperative life-threatening dysrhythmias was very low in the two groups. No significant reduction of postoperative mechanical ventilation, intensive care unit or hospital stays was reported with epidural analgesia. The incidence of postoperative infections was higher than expected in the two groups because of the poor properative clinical status of most of the children included in the study

Utilisation de la ventilation non invasive au long cours lors de BPCO.

Non-invasive ventilation (NIV) is recognized as first line therapy in acute hypercapnic respiratory failure and chronic alveolar hypoventilation caused by several diseases (restrictive thoracic disorders, neuromuscular disease and obesity-hypoventilation syndrome). In Switzerland and other European countries, long-term NIV has also been applied in hypercapnic patients with chronic obstructive pulmonary disease (COPD). However, only recently has conclusive evidence showing benefits of long-term NIV become available. Long-term NIV in COPD has now shown its efficacy in many studies. However, despite these findings, indications, ventilatory settings and monitoring remain poorly known and topic of debate