Modification de l'impédance de surface d'un matériau par contrôle actif (Application à la caractérisation et à l'optimisation d'un absorbant acoustique)

L@'essor considérable des transports depuis quelques décennies a contribué à l'émergence d'une nouvelle forme de pollution par le bruit. En particulier dans le domaine aéronautique, la diminution des nuisances sonores des turboréacteurs est assurée par l'application de traitements acoustiques sur les parois de la nacelle. Notre étude concerne le développement d'une cellule absorbante hybride combinant les propriétés passives d'un milieu poreux et un module de contrôle actif induisant une annulation de la pression à l'arrière du matériau. Un tel système est conçu pour étendre le domaine fréquentiel d'atténuation sonore. L'optimisation du traitement hybride est réalisé dans le cas spécifique d'une veine de laboratoire spécialement développée à cet effet. La caractérisation et l'optimisation de la composante passive de l'absorbant hybride sont d'abord effecutées au niveau théorique. Le concept d'absorption hybride est ensuite validé au niveau expérimental en présence d'écoulement.The@recent development of automotive and aircraft transport contributed to the emergence of a new kind of nuisances called the noise pollution. In particular concerning the aeronautic domain turbo-engine noise damping is achieved by applying acoustic treatments on the nacelle walls. The topic of our study concerns the design of a hybrid absorbent cell combining the passive properties of a porous material and active control techniques ensuring a pressure release at the porous sheet rear face. Such an acoustic system is actually studied to enlarge the frequency range of noise reduction. The hybrid liner optimization is realized in case of a laboratory flow duct specifically developed for our application. The hybrid absorption concept is then experimentally validated under grazing flow.LYON-Ecole Centrale (690812301) / SudocSudocFranceF

Noise reduction in a flow duct : implementation of a hybrid passive/active solution

International audienc

Root rot of pea: characterization and biocontrol of the soil-borne disease complex including Aphanomyces euteiches

National audiencePea root rot is an increasing constraint in most of intensive pea cropping areas across the globe. The pathogenic complex responsible for the disease is composed of soil-borne fungal and oomycete pathogens such as Fusarium solani, F.oxysporum, F. avenaceum, F. culmorum, Rhizoctonia solani, Thielaviopsis basicola, Ascochyta pinodella, Pythium spp., Aphanomyces euteiches and probably others not yet identified. The diversity of their ecological and pathogenic properties can explain the worldwide dispersion of the disease and the absence of chemical, agricultural or genetic control tools. My research program aims at characterizing the parasitic consortium occurring in the North of France and at proposing biocontrol strategies. First, a field sampling strategy is being determined to measure Inoculum Potential and assess A. euteiches risk. In addition, a comparative analysis of the fungal and oomycete diversity from roots and rhizospheres of symptomatic and asymptomatic plants of infested fields is carried out. This analysis consists in a combination of microbiological isolations and molecular methods (Metabarcoding) to characterize the microbial complex responsible for the disease and identify putative biocontrol taxa. Promising candidates and commercial products with a biocontrol activity against oomycetes and fungi which could be part of the microbial complex will be tested in vitro, in greenhouse, and in field

Root rot of <em>pea</em> : characterization and biocontrol of the soil-borne disease complex including <em>Aphanomyces</em> euteiches

National audiencePea root rot is an increasing constraint in most of intensive pea cropping areas across the globe. The pathogenic complex responsible for the disease is composed of soil-borne fungal and oomycete pathogens such as Fusarium solani, F.oxysporum, F. avenaceum, F. culmorum, Rhizoctonia solani, Thielaviopsis basicola, Ascochyta pinodella, Pythium spp., Aphanomyces euteiches and probably others not yet identified. The diversity of their ecological and pathogenic properties can explain the worldwide dispersion of the disease and the absence of chemical, agricultural or genetic control tools. My research program aims at characterizing the parasitic consortium occurring in the North of France and at proposing biocontrol strategies. First, a field sampling strategy is being determined to measure Inoculum Potential and assess A. euteiches risk. In addition, a comparative analysis of the fungal and oomycete diversity from roots and rhizospheres of symptomatic and asymptomatic plants of infested fields is carried out. This analysis consists in a combination of microbiological isolations and molecular methods (Metabarcoding) to characterize the microbial complex responsible for the disease and identify putative biocontrol taxa. Promising candidates and commercial products with a biocontrol activity against oomycetes and fungi which could be part of the microbial complex will be tested in vitro, in greenhouse, and in field

Identification, pathogenicity and community dynamics of fungi and oomycetes associated with pea root rot in northern France

International audienceAbstract The pea root rot complex is a major concern for green pea production worldwide. This study aimed at characterizing its composition and dynamics throughout a cropping season in northern France. To this end, fungi and oomycetes were isolated from green pea plant roots with symptoms sampled at the flowering stage in 22 fields in 2017, and at the pea emergence, elongation and flowering stages in two fields in 2018. Out of 646 isolates collected, 317 were identified using molecular markers. Fusarium oxysporum, F. solani and F. redolens were highly predominant. Pathogenicity tests separated the isolates into four aggressiveness groups. F. solani isolates were the most aggressive. Phylogenetic analysis of their TEF1 sequences showed that they mainly belonged to the F. pisi lineage, and that F. oxysporum isolates were genetically close to isolates from the UK that did not belong to the forma specialis pisi. In addition, several Clonostachys rhizophaga isolates are reported for the first time to cause pea root rot. The oomycetes were rarely found and were represented by a few Pythium spp. isolates. Lastly, this study shows that the fungal and oomycete communities associated with pea root rot change during the cropping season. The level of dissimilarity of the root-rot-associated communities decreased throughout the cropping season towards a more similar composition at the flowering stage, dominated by F. solani, F. oxysporum and F. redolens. The proportion of nonpathogenic to weakly pathogenic isolates decreased progressively during the growing season in favour of moderately to highly pathogenic isolates

Risk assessment of Aphanomyces euteiches root rot disease: quantification of low inoculum densities in field soils using droplet digital PCR

International audienceAphanomyces euteiches Drechs is a pathogenic soil-borne oomycete that causes root rot of legumes, one of the most serious diseases affecting legume production worldwide. There is currently no registered pesticide and no available resistant pea cultivar. Avoidance of infested fields based on disease risk assessment prior to pea sowing remains the main method available to manage the disease, but time-consuming bioassays are required to assess disease severity on susceptible plants grown in field soil samples. Direct quantification of A. euteiches inoculum in the soil by targeting multicopy genomic sequences of the internal transcribed spacer 1 with a qPCR-based method has been proposed as a rapid alternative for disease prediction. However, the method lacks sensitivity to accurately quantify low inoculum levels from naturally infested fields. We developed a suitable methodology based on droplet digital PCR (ddPCR) to quantify low A. euteiches inoculum levels in naturally infested soils. The methodology was validated on 200 soil samples taken from four naturally infested fields in the main pea cropping area in the north of France. The comparative analysis of inoculum density and disease severity of the 50 samples within each of the four fields revealed a non-homogeneous distribution of the A. euteiches population; this explains why the disease is visible in the form of foci. A significant relationship between pea root rot disease severity determined by bioassays and A. euteiches inoculum density was highlighted, and a linear mixed model is proposed to predict disease severity from inoculum density

Use of genomic grade index to improve tumor grading of invasive lobular breast carcinoma.

info:eu-repo/semantics/nonPublishe

Clinical and pathological features of cutaneous manifestations in VEXAS syndrome: A multicenter retrospective study of 59 cases

International audienc

COVID-19 outcomes in patients with inflammatory rheumatic and musculoskeletal diseases treated with rituximab: a cohort study

International audienceBackground: Various observations have suggested that the course of COVID-19 might be less favourable in patients with inflammatory rheumatic and musculoskeletal diseases receiving rituximab compared with those not receiving rituximab. We aimed to investigate whether treatment with rituximab is associated with severe COVID-19 outcomes in patients with inflammatory rheumatic and musculoskeletal diseases.Methods: In this cohort study, we analysed data from the French RMD COVID-19 cohort, which included patients aged 18 years or older with inflammatory rheumatic and musculoskeletal diseases and highly suspected or confirmed COVID-19. The primary endpoint was the severity of COVID-19 in patients treated with rituximab (rituximab group) compared with patients who did not receive rituximab (no rituximab group). Severe disease was defined as that requiring admission to an intensive care unit or leading to death. Secondary objectives were to analyse deaths and duration of hospital stay. The inverse probability of treatment weighting propensity score method was used to adjust for potential confounding factors (age, sex, arterial hypertension, diabetes, smoking status, body-mass index, interstitial lung disease, cardiovascular diseases, cancer, corticosteroid use, chronic renal failure, and the underlying disease [rheumatoid arthritis vs others]). Odds ratios and hazard ratios and their 95% CIs were calculated as effect size, by dividing the two population mean differences by their SD. This study is registered with ClinicalTrials.gov, NCT04353609.Findings: Between April 15, 2020, and Nov 20, 2020, data were collected for 1090 patients (mean age 55·2 years [SD 16·4]); 734 (67%) were female and 356 (33%) were male. Of the 1090 patients, 137 (13%) developed severe COVID-19 and 89 (8%) died. After adjusting for potential confounding factors, severe disease was observed more frequently (effect size 3·26, 95% CI 1·66-6·40, p=0·0006) and the duration of hospital stay was markedly longer (0·62, 0·46-0·85, p=0·0024) in the 63 patients in the rituximab group than in the 1027 patients in the no rituximab group. 13 (21%) of 63 patients in the rituximab group died compared with 76 (7%) of 1027 patients in the no rituximab group, but the adjusted risk of death was not significantly increased in the rituximab group (effect size 1·32, 95% CI 0·55-3·19, p=0·53).Interpretation: Rituximab therapy is associated with more severe COVID-19. Rituximab will have to be prescribed with particular caution in patients with inflammatory rheumatic and musculoskeletal diseases