15 research outputs found

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

    Get PDF
    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/)

    Counterfeit coinage of the Holy Roman Empire in the 16th century: silvering process and archaeometallurgical replications

    No full text
    International audienceThe Preuschdorf coin hoard, found in the Alsace, offered the opportunity to study silver-plated coins from the 16th to 17th century AD. 36 silvered coins have been studied and two silvering processes have been found: amalgam silvering for 44 % of the coins and a thin layer of pure silver for 56 % of the coins. The majority of the coins silvered with mercury were struck in Palatinate whereas those with pure silver come from the city of St. Gallen in Switzerland. In order to confirm these technologies, replications have been undertaken at the archaeological experimental platform in Melle (Deux SĂšvres, France). The combination of the observation of non-restored coins and of the replication production gives a good representation of the silvering processes used in the Holy Roman Empire in the 16th century for producing counterfeit coin

    Maßtriser les adventices dans le blé par un couvert permanent de légumineuse dans un systÚme en semis direct sous couvert végétal géré sans glyphosate : quelques enseignements du Casdar Engaged

    No full text
    National audienceParmi les systĂšmes en agriculture de conservation, le semis direct sous couvert vĂ©gĂ©tal a pourobjectif de maintenir, tout au long de la rotation, un couvert permanent de lĂ©gumineuses danslaquelle l’agriculteur viendra semer en direct ses cultures. Parmi les objectifs visĂ©s, ce couvert doitnotamment permettre de gĂ©rer les adventices. Pour cela, il est nĂ©cessaire qu’il soit suffisammentdĂ©veloppĂ© pour avoir un effet compĂ©titif vis-Ă -vis des adventices. Toutefois, trop dĂ©veloppĂ©, il peutĂ©galement rentrer en compĂ©tition avec la culture principale et impacter le rendement. Dans lecadre du projet ENGAGED, deux leviers pour attĂ©nuer l’effet de compĂ©tition sur le blĂ© ont Ă©tĂ©identifiĂ©s : l’augmentation de la densitĂ© de semis du blĂ© et une rĂ©gulation chimique raisonnĂ©e auprintemps. Les deux annĂ©es d’expĂ©rimentation menĂ©s sur des parcelles d’agriculteurs ont montrĂ©qu’une forte augmentation de la densitĂ© de semis de blĂ© permet un contrĂŽle des adventicescomparable au glyphosate en sortie hiver, Ă  rendement de blĂ© assez proches. Il sembleĂ©galement possible de rĂ©duire la dose utilisĂ©e lors de la rĂ©gulation du couvert au printempsmais des Ă©tudes complĂ©mentaires sont nĂ©cessaires. Ces rĂ©sultats ont Ă©tĂ© jugĂ©s encourageantspar les agriculteurs expĂ©rimentateurs mais pas suffisants pour envisager une gĂ©nĂ©ralisation decette pratique sur l’ensemble de leurs parcelles, compte tenu du risque de non maĂźtrised’adventices Ă  moyen terme. D’autres pistes restent Ă  explorer comme par exemple la rĂ©gulationmĂ©canique du couvert permanent

    Le semis direct sous couvert permanent sans glyphosate Durant trois années, le projet CasDar engaged a testé différentes stratégies de gestion des adventices et de la couverture végétale

    No full text
    National audienceContexte - Afin de pĂ©renniserle semis direct sous couvert permanent au-delĂ  d’une potentielleinterdiction du glyphosate, le projetCasDar Engaged (2018-2022) a rĂ©uni, autour d’agriculteurs normands,diffĂ©rents acteurs agricoles pour unprojet de trois ans en trois phases :1) veille technique sur les alternatives Ă  l’utilisation du glyphosate ;2) expĂ©rimentation au champd’itinĂ©raires techniques dans unrĂ©seau de parcelles d’agriculteurs ;3) reconception de systĂšmes deculture en atelier avec des agriculteurs et conseillers.Ÿ RĂ©suLtAts - Si la veille technique a permis d’identifier destechniques innovantes Ă  mettreen Ɠuvre pendant les pĂ©riodesde culture et d’interculture, lesessais au champ ont testĂ© des itinĂ©raires techniques de blĂ© commele broyage du couvert, l’augmentation de la densitĂ© de semis et desprogrammes herbicides adaptĂ©s.La reconception en atelier a permis, Ă  travers des travaux d’élĂšvesingĂ©nieurs et d’ateliers avec desconseillers, de confronter les agriculteurs Ă  des situations de ruptureplus fortes que celles engagĂ©es surleur ferme

    Thermal stability and phase transformation of semi-crystalline mesostructured TiO2 in the presence of heteroelements

    Get PDF
    International audienceThe effect of the introduction of heteroelement (Si, P, Al, Ge, Ga and Zr) by direct synthesis on the thermal stability of mesostructured titania prepared by the soft templating pathway has been investigated. All materials have been surfactant-extracted with EtOH and calcined at different temperatures up to 900 °C. Ti4+ can be partially substituted by most of the investigated heteroelements but they mainly form an oxide amorphous phase surrounding the titania anatase particles. Results obtained by SAXS, X-Ray diffraction, Raman spectroscopy and manometry nitrogen adsorption-desorption show that the crystallization of the amorphous titania into nanosized anatase particles and the transition from anatase to rutile occur at higher temperature with the addition of the heteroelement. Even if the lattice distortion introduced by the partial Ti4+ substitution can participate to this phenomenon, it is mainly due the «glass » effect induced by the presence of the heteroelement in the TiO2 amorphous phase, which limits the growth of the nanosized anatase crystallites. However, when the crystallites reach a limit size, the collapse of the mesostructure occurs. With increasing the calcination temperature, the anatase titania particles become bigger and bigger, the transition from anatase to rutile takes place and the heteroelement can crystallize or be integrated in a crystalline phase. Among the considered heteroelements and by comparison with the bare mesostructured TiO2, the most beneficial effect is obtained in the presence of Si4+ and PO43− for which the mesostructure collapse at higher temperature by about two hundred Celsius degrees. Al3+ and Ge4+ enhance the thermal stability by about a hundred Celsius degrees and Ga3+ or Zr4+ have no significant effect on the temperature at which the mesostructure collapses

    First chemo-enzymatic synthesis of the ( R )-Taniguchi lactone and substrate profiles of CAMO and OTEMO, two new Baeyer– Villiger monooxygenases

    Get PDF
    This study investigates the substrate profile of cycloalkanone monooxygenase and 2-oxo-Δ3-4,5,5-trimethylcyclopentenylacetyl-coenzyme A monooxygenase, two recently discovered enzymes of the Baeyer–Villiger monooxygenase family, used as whole-cell biocatalysts. Biooxidations of a diverse set of ketones were performed on analytical scale: desymmetrization of substituted prochiral cyclobutanones and cyclohexanones, regiodivergent oxidation of terpenones and bicyclic ketones, as well as kinetic resolution of racemic cycloketones. We demonstrated the applicability of the title enzymes in the enantioselective synthesis of (R)-(−)-Taniguchi lactone, a building block for the preparation of various natural product analogs such as ent-quinine.Austrian Scientific Foundation (FWF)EU-FP7 Oxygree

    Benefits and risks of noninvasive oxygenation strategy in COVID-19: a multicenter, prospective cohort study (COVID-ICU) in 137 hospitals

    No full text
    International audienceAbstract Rational To evaluate the respective impact of standard oxygen, high-flow nasal cannula (HFNC) and noninvasive ventilation (NIV) on oxygenation failure rate and mortality in COVID-19 patients admitted to intensive care units (ICUs). Methods Multicenter, prospective cohort study (COVID-ICU) in 137 hospitals in France, Belgium, and Switzerland. Demographic, clinical, respiratory support, oxygenation failure, and survival data were collected. Oxygenation failure was defined as either intubation or death in the ICU without intubation. Variables independently associated with oxygenation failure and Day-90 mortality were assessed using multivariate logistic regression. Results From February 25 to May 4, 2020, 4754 patients were admitted in ICU. Of these, 1491 patients were not intubated on the day of ICU admission and received standard oxygen therapy (51%), HFNC (38%), or NIV (11%) ( P < 0.001). Oxygenation failure occurred in 739 (50%) patients (678 intubation and 61 death). For standard oxygen, HFNC, and NIV, oxygenation failure rate was 49%, 48%, and 60% ( P < 0.001). By multivariate analysis, HFNC (odds ratio [OR] 0.60, 95% confidence interval [CI] 0.36–0.99, P = 0.013) but not NIV (OR 1.57, 95% CI 0.78–3.21) was associated with a reduction in oxygenation failure). Overall 90-day mortality was 21%. By multivariable analysis, HFNC was not associated with a change in mortality (OR 0.90, 95% CI 0.61–1.33), while NIV was associated with increased mortality (OR 2.75, 95% CI 1.79–4.21, P < 0.001). Conclusion In patients with COVID-19, HFNC was associated with a reduction in oxygenation failure without improvement in 90-day mortality, whereas NIV was associated with a higher mortality in these patients. Randomized controlled trials are needed
    corecore