89 research outputs found

    Design, development and delivery of one /1/ breadboard and three /3/ production units of a 75 VA integrated static inverter Monthly report no. 15

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    Flip-flop arrays, power transistors, epitaxial stress, and other technological developments in integrated static inverter progra

    Passive models of viscothermal wave propagation in acoustic tubes

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    International audienceA continued fraction expansion to the immittances defining viscothermal wave propagation in acylindrical tube has been presented recently in this journal, intended as a starting point for timedomain numerical method design. Though the approximation has the great benefit of passivity, orpositive realness under truncation, its convergence is slow leading to approximations of high orderin practice. Other passive structures, when combined with optimisation methods, can lead to goodaccuracy over a wide frequency range, and for relatively low order

    Polynucleobacter necessarius, a model for genome reduction in both free-living and symbiotic bacteria

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    We present the complete genomic sequence of the essential symbiont Polynucleobacter necessarius (Betaproteobacteria), which is a valuable case study for several reasons. First, it is hosted by a ciliated protist, Euplotes; bacterial symbionts of ciliates are still poorly known because of a lack of extensive molecular data. Second, the single species P. necessarius contains both symbiotic and free-living strains, allowing for a comparison between closely related organisms with different ecologies. Third, free-living P. necessarius strains are exceptional by themselves because of their small genome size, reduced metabolic flexibility, and high worldwide abundance in freshwater systems. We provide a comparative analysis of P. necessarius metabolism and explore the peculiar features of a genome reduction that occurred on an already streamlined genome. We compare this unusual system with current hypotheses for genome erosion in symbionts and free-living bacteria, propose modifications to the presently accepted model, and discuss the potential consequences of translesion DNA polymerase loss

    A robust and rapid xenograft model to assess efficacy of chemotherapeutic agents for human acute myeloid leukemia

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    International audienceRelevant preclinical mouse models are crucial to screen new therapeutic agents for acute myeloid leukemia (AML). Current in vivo models based on the use of patient samples are not easy to establish and manipulate in the laboratory. Our objective was to develop robust xenograft models of human AML using well-characterized cell lines as a more accessible and faster alternative to those incorporating the use of patient-derived AML cells. Five widely used AML cell lines representing various AML subtypes were transplanted and expanded into highly immunodeficient non-obese diabetic/LtSz-severe combined immunodeficiency IL2R gamma(null)(c) mice (for example, cell line-derived xenografts). We show here that bone marrow sublethal conditioning with busulfan or irradiation has equal efficiency for the xenotransplantation of AML cell lines. Although higher number of injected AML cells did not change tumor engraftment in bone marrow and spleen, it significantly reduced the overall survival in mice for all tested AML cell lines. On the basis of AML cell characteristics, these models also exhibited a broad range of overall mouse survival, engraftment, tissue infiltration and aggressiveness. Thus, we have established a robust, rapid and straightforward in vivo model based on engraftment behavior of AML cell lines, all vital prerequisites for testing new therapeutic agents in preclinical studies

    Contribution to harmonic balance calculations of self-sustained periodic oscillations with focus on single-reed instruments

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    International audienceThe harmonic balance method ͑HBM͒ was originally developed for finding periodic solutions of electronical and mechanical systems under a periodic force, but has been adapted to self-sustained musical instruments. Unlike time-domain methods, this frequency-domain method does not capture transients and so is not adapted for sound synthesis. However, its independence of time makes it very useful for studying any periodic solution, whether stable or unstable, without care of particular initial conditions in time. A computer program for solving general problems involving nonlinearly coupled exciter and resonator, HARMBAL, has been developed based on the HBM. The method as well as convergence improvements and continuation facilities are thoroughly presented and discussed in the present paper. Applications of the method are demonstrated, especially on problems with severe difficulties of convergence: the Helmholtz motion ͑square signals͒ of single-reed instruments when no losses are taken into account, the reed being modeled as a simple spring

    Tracheostomy in the COVID-19 era: global and multidisciplinary guidance

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    Global health care is experiencing an unprecedented surge in the number of critically ill patients who require mechanical ventilation due to the COVID-19 pandemic. The requirement for relatively long periods of ventilation in those who survive means that many are considered for tracheostomy to free patients from ventilatory support and maximise scarce resources. COVID-19 provides unique challenges for tracheostomy care: health-care workers need to safely undertake tracheostomy procedures and manage patients afterwards, minimising risks of nosocomial transmission and compromises in the quality of care. Conflicting recommendations exist about case selection, the timing and performance of tracheostomy, and the subsequent management of patients. In response, we convened an international working group of individuals with relevant expertise in tracheostomy. We did a literature and internet search for reports of research pertaining to tracheostomy during the COVID-19 pandemic, supplemented by sources comprising statements and guidance on tracheostomy care. By synthesising early experiences from countries that have managed a surge in patient numbers, emerging virological data, and international, multidisciplinary expert opinion, we aim to provide consensus guidelines and recommendations on the conduct and management of tracheostomy during the COVID-19 pandemic

    Features of Mild-to-Moderate COVID-19 Patients with Dysphonia

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    Introduction To explore the prevalence of dysphonia in European patients with mild-to-moderate COVID-19 and the clinical features of dysphonic patients. Methods The clinical and epidemiological data of 702 patients with mild-to-moderate COVID-19 were collected from 19 European Hospitals. The following data were extracted: age, sex, ethnicity, tobacco consumption, comorbidities, general and otolaryngological symptoms. Dysphonia and otolaryngological symptoms were self-assessed through a 4-point scale. The prevalence of dysphonia, as part of the COVID-19 symptoms, was assessed. The outcomes were compared between dysphonic and non-dysphonic patients. The association between dysphonia severity and outcomes was studied through Bayesian analysis. Results A total of 188 patients were dysphonic, accounting for 26.8% of cases. Females developed more frequently dysphonia than males (p=0.022). The proportion of smokers was significantly higher in the dysphonic group (p=0.042). The prevalence of the following symptoms was higher in dysphonic patients compared with non-dysphonic patients: cough, chest pain, sticky sputum, arthralgia, diarrhea, headache, fatigue, nausea and vomiting. The severity of dyspnea, dysphagia, ear pain, face pain, throat pain and nasal obstruction was higher in dysphonic group compared with non-dysphonic group. There were significant associations between the severity of dysphonia, dysphagia and cough. Conclusion Dysphonia may be encountered in a quarter of patients with mild-to-moderate COVID-19 and should be considered as a symptom list of the infection. Dysphonic COVID-19 patients are more symptomatic than non-dysphonic individuals. Future studies are needed to investigate the relevance of dysphonia in the COVID-19 clinical presentation
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