Topological dynamics of adiabatic cat states

We consider a qubit topologically coupled to two quantum modes. We show that any initial separable state of this system generically evolves into an adiabatic cat state. Such a state is a superposition of two adiabatic states in which the qubit is entangled between the modes. The topological coupling between the qubit and the modes gives rise to the separation in energy between these two components which evolve into states with distinguishable energy content

Merville-Franceville-Plage – Les Batteries

Le projet d’aménager un parking automobile par l’association franco-britannique de gestion du Musée de la batterie de Merville a donné lieu, en février 2018, à un diagnostic portant sur 1,3 ha. La parcelle concernée (cadastre section A0, parcelle 45p) est contiguë, à l’est, du site historique de la batterie allemande de Merville, prise d’assaut par les parachutistes anglais du 9e bataillon aéroporté (The Parachute Regiment, 6th Airborne Division) dans la nuit du 6 juin 1944. Tout au long de l..

Impact of basin burial and exhumation on Jurassic carbonates diagenesis on both sides of a thick clay barrier (Paris Basin, NE France).

27 pagesInternational audienceSeveral diagenetic models have been proposed for Middle and Upper Jurassic carbonates of the eastern Paris Basin. The paragenetic sequences are compared in both aquifers to propose a diagenetic model for the Middle and Late Jurassic deposits as a whole. Petrographic (optical and cathodoluminescence microscopy), structural (fracture orientations) and geochemical (δ18O, δ13C, REE) studies were conducted to characterize diagenetic cements, with a focus on blocky calcite cements, and their connection with fracturation events. Four generations of blocky calcite (Cal1-Cal4) are identified. Cal1 and Cal2 are widespread in the dominantly grain-supported facies of the Middle Jurassic limestones (about 90% of the cementation), whereas they are limited in the Oxfordian because grain-supported facies are restricted to certain stratigraphic levels. Cal1 and Cal2 blocky spars precipitated during burial in a reducing environment from mixed marine-meteoric waters and/or buffered meteoric waters. The meteoric waters probably entered aquifers during the Late Cimmerian (Jurassic/Cretaceous boundary) and Late Aptian (Early Cretaceous) unconformities. The amount of Cal2 cement is thought to be linked to the intensity of burial pressure dissolution, which in turn was partly controlled by the clay content of the host rocks. Cal3 and Cal4 are associated with telogenetic fracturing phases. The succession of Cal3 and Cal4 calcite relates to the transition towards oxidizing conditions during an opening of the system to meteoric waters at higher water/rock ratios. These meteoric fluids circulated along Pyrenean, Oligocene and Alpine fractures and generated both dissolution and subsequent cementation in Oxfordian vugs in mud-supported facies and in poorly stylolitized grainstones. However, these cements filled only the residual porosity in Middle Jurassic limestones. In addition to fluorine inputs, fracturation also permitted inputs of sulphur possibly due to weathering of Triassic or Purbeckian evaporites or H2S input during Paleogene times

High-flow oxygen therapy versus noninvasive ventilation: a randomised physiological crossover study of alveolar recruitment in acute respiratory failure.

High-flow nasal cannula (HFNC) oxygen therapy has recently shown clinical benefits in hypoxaemic acute respiratory failure (ARF) patients, while the value of noninvasive ventilation (NIV) remains debated. The primary end-point was to compare alveolar recruitment using global end-expiratory electrical lung impedance (EELI) between HFNC and NIV. Secondary end-points compared regional EELI, lung volumes (global and regional tidal volume variation (V (T))), respiratory parameters, haemodynamic tolerance, dyspnoea and patient comfort between HFNC and NIV, relative to face mask (FM). A prospective randomised crossover physiological study was conducted in patients with hypoxaemic ARF due to pneumonia. They received alternately HFNC, NIV and FM. 16 patients were included. Global EELI was 4083 with NIV and 2921 with HFNC (p=0.4). Compared to FM, NIV and HFNC significantly increased global EELI by 1810.5 (95% CI 857-2646) and 826 (95% CI 399.5-2361), respectively. Global and regional V (T) increased significantly with NIV compared to HFNC or FM, but not between HFNC and FM. NIV yielded a significantly higher pulse oxygen saturation/inspired oxygen fraction ratio compared to HFNC (p=0.03). No significant difference was observed between HFNC, NIV and FM for dyspnoea. Patient comfort score with FM was not significantly different than with HFNC (p=0.1), but was lower with NIV (p=0.001). This study suggests a potential benefit of HFNC and NIV on alveolar recruitment in patients with hypoxaemic ARF. In contrast with HFNC, NIV increased lung volumes, which may contribute to overdistension and its potentially deleterious effect in these patients

T-Cell Artificial Focal Triggering Tools: Linking Surface Interactions with Cell Response

T-cell activation is a key event in the immune system, involving the interaction of several receptor ligand pairs in a complex intercellular contact that forms between T-cell and antigen-presenting cells. Molecular components implicated in contact formation have been identified, but the mechanism of activation and the link between molecular interactions and cell response remain poorly understood due to the complexity and dynamics exhibited by whole cell-cell conjugates. Here we demonstrate that simplified model colloids grafted so as to target appropriate cell receptors can be efficiently used to explore the relationship of receptor engagement to the T-cell response. Using immortalized Jurkat T cells, we monitored both binding and activation events, as seen by changes in the intracellular calcium concentration. Our experimental strategy used flow cytometry analysis to follow the short time scale cell response in populations of thousands of cells. We targeted both T-cell receptor CD3 (TCR/CD3) and leukocyte-function-associated antigen (LFA-1) alone or in combination. We showed that specific engagement of TCR/CD3 with a single particle induced a transient calcium signal, confirming previous results and validating our approach. By decreasing anti-CD3 particle density, we showed that contact nucleation was the most crucial and determining step in the cell-particle interaction under dynamic conditions, due to shear stress produced by hydrodynamic flow. Introduction of LFA-1 adhesion molecule ligands at the surface of the particle overcame this limitation and elucidated the low TCR/CD3 ligand density regime. Despite their simplicity, model colloids induced relevant biological responses which consistently echoed whole cell behavior. We thus concluded that this biophysical approach provides useful tools for investigating initial events in T-cell activation, and should enable the design of intelligent artificial systems for adoptive immunotherapy

Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.

RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 ≥60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

De l’EPHE à l’EHESS : l’esprit de la VIe Section

La VIe Section de l’École pratique des hautes études occupe une place importante dans les parcours et les témoignages des historiens de notre corpus : il s’agissait donc d’un angle probant dans le cadre de notre projet global pour interroger le nœud 1968 dans l’évolution des cadres de recherche et d’enseignement pour les historiens. L’histoire de cette VIe Section, créée en 1947, puis devenue l’École des hautes études en sciences sociales, EHESS, en 1975, est bien connue, notamment depuis la ..

Activation artificielle de la cellule T, rôle des contraintes mécaniques

Au cours de cette thèse, nous avons étudié l activation artificielle de la cellule T par des colloïdes synthétiques et exploré le rôle des contraintes mécaniques dans le processus d activation. La reconnaissance spécifique par la cellule T d un antigène présenté par une cellule présentatrice d antigène est une interaction majeure qui conduit à la mise en place d une réponse immunitaire spécifique. Cette interaction est également un élément clef des stratégies d immunothérapie. Nous avons dans un premier temps, développé un système modèle composé d une cellule T de la lignée Jurkat et de colloïdes magnétiques diversement greffés pour engager des ligands spécifiques du lymphocyte T. Nous avons réalisé des outils capables de manipuler artificiellement l activation de la cellule T et examiné la relation entre les caractéristiques de l interaction de surface telles que nous pouvons les piloter avec les colloïdes modèles et la réponse cellulaire induite.Dans un second temps, nous avons sondé l effet des contraintes mécaniques sur l activation de la cellule T en construisant une expérience basée sur l utilisation d une pointe électromagnétique permettant d appliquer des forces contrôlées sur les colloïdes magnétiques fixés aux cellules. Nous montrons ici les premiers résultats qui indiquent que l on peut activer la signalisation de la cellule T en appliquant une force sur le complexe TCR/CD3. Ces résultats très nouveaux suggèrent que les contraintes mécaniques pourraient faire partie intégrante du mécanisme d activation de la cellule T. Pour finir, nous discuterons des perspectives de ces résultats pour le contrôle de l activation de la cellule T et l ingénierie cellulaire.PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF