Frequency parametrization to numerically predict flutter in turbomachinery

In the quest for performance, modern turbomachinery designs are increasingly proner to flutter hazards. Unfortunately, their prediction is currently too expensive and inaccurate for industrial purpose. A significant step towards faster methods would consist in substituting a sequential algorithm to the classical iterative ones encountered in loose coupling strategies. The approach proposed here makes it possible through the use of a meta-model taking into account the sensitivity to design variables. This parametrized method is evaluated on a standard well referenced turbine configuration

Lung transplantation after allogeneic stem cell transplantation : a pan-European experience

Late-onset noninfectious pulmonary complications (LONIPCs) affect 6% of allogeneic stem cell transplantation (SCT) recipients within 5 years, conferring subsequent 5-year survival of 50%. Lung transplantation is rarely performed in this setting due to concomitant extrapulmonary morbidity, excessive immunosuppression and concerns about recurring malignancy being considered contraindications. This study assesses survival in highly selected patients undergoing lung transplantation for LONIPCs after SCT. SCT patients undergoing lung transplantation at 20 European centres between 1996 and 2014 were included. Clinical data pre- and post-lung transplantation were reviewed. Propensity score-matched controls were generated from the Eurotransplant and Scandiatransplant registries. Kaplan-Meier survival analysis and Cox proportional hazard regression models evaluating predictors of graft loss were performed. Graft survival at 1, 3 and 5 years of 84%, 72% and 67%, respectively, among the 105 SCT patients proved comparable to controls (p=0.75). Sepsis accounted for 15 out of 37 deaths (41%), with prior mechanical ventilation (HR 6.9, 95% CI 1.0-46.7; p Lung transplantation outcomes following SCT were comparable to other end-stage diseases. Lung transplantation should be considered feasible in selected candidates. No SCT-specific factors influencing outcome were identified within this carefully selected patient cohort.Peer reviewe

Time-harmonic Navier-Stokes computations of forced shock-wave oscillations in a transonic nozzle

International audienceThis study focuses on the development of frequency-based Reynolds-Averaged Navier-Stokes methods in the presence of harmonic excitations. Two different methodologies are proposed to alleviate the problem of high computational costs of conventional time-domain time-nonlinear approaches due to the capture of the long transients. A time-linearized approach is adopted using either the simple frozen-turbulence-scales assumption or the full linearization of the turbulence model. In order to account for nonlinear coupling between harmonics, a flexible time-domain Fourier-based solver is derived from a Reynolds-Averaged Navier-Stokes solver based on a local dual time stepping technique. Various flow regimes, involving forced shock-wave oscillations due to an elliptical cam placed at the nozzle exit and forced vibrations of test objects, are investigated to assess the robustness and the computational efficiency of the two frequency-based approaches in the presence of recirculating flows

Infection par l’hantavirus Puumala en Isère : une extension géographique de cette zoonose en France

International audience

Legionellosis and Lung Abscesses: Contribution of Legionella Quantitative Real-Time PCR to an Adapted Followup

We report a case of severe Legionnaires' disease (LD) complicated by a lung abscess in an immunocompetent patient who required ECMO therapy and thoracic surgery. The results of repeated Legionella quantitative real-time PCR performed on both sera and respiratory samples correlated with the LD severity and the poor clinical outcome. Moreover, the PCR allowed for the detection of Legionella DNA in the lung abscess specimen, which was negative when cultured for Legionella. This case report provides a logical basis for further investigations to examine whether the Legionella quantitative PCR could improve the assessment of LD severity and constitute a prognostic marker

Pericardial and pleural diffusion of voriconazole during disseminated invasive aspergillosis: report of a case with successful outcome

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Effects of inhaled fenoterol and positive end-expiratory pressure on the respiratory mechanics of patients with chronic obstructive pulmonary disease

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Cardiac ryanodine receptors control heart rate and rhythmicity in adult mice

AimsThe molecular mechanisms controlling heart function and rhythmicity are incompletely understood. While it is widely accepted that the type 2 ryanodine receptor (Ryr2) is the major Ca2+ release channel in excitation-contraction coupling, the role of these channels in setting a consistent beating rate remains controversial. Gain-of-function RYR2 mutations in humans and genetically engineered mouse models are known to cause Ca 2+ leak, arrhythmias, and sudden cardiac death. Embryonic stem-cell derived cardiomyocytes lacking Ryr2 display slower beating rates, but no supporting in vivo evidence has been presented. The aim of the present study was to test the hypothesis that RYR2 loss-of-function would reduce heart rate and rhythmicity in vivo.Methods and resultsWe generated inducible, tissue-specific Ryr2 knockout mice with acute ∼50 loss of RYR2 protein in the heart but not in other tissues. Echocardiography, working heart perfusion, and in vivo ECG telemetry demonstrated that deletion of Ryr2 was sufficient to cause bradycardia and arrhythmia. Our results also show that cardiac Ryr2 knockout mice exhibit functional and structural hallmarks of heart failure, including sudden cardiac death.ConclusionThese results illustrate that the RYR2 channel plays an essential role in pacing heart rate. Moreover, we find that RYR2 loss-of-function can lead to fatal arrhythmias typically associated with gain-of-function mutations. Given that RYR2 levels can be reduced in pathological conditions, including heart failure and diabetic cardiomyopathy, we predict that RYR2 loss contributes to disease-associated bradycardia, arrhythmia, and sudden death. © 2012 The Author.link_to_subscribed_fulltex