Estimation de la contribution des émissions Îhiculaires à l'échappement et hors-échappement aux teneurs atmosphériques en PM10 par Positive Matrix Factorization (PMF)

The goal of this work is the development of a methodology allowing the assessment of road traffic exhaust and non-exhaust contributions (resuspension of road dusts, from brakes, tyres and road-surface-wear, from the corrosion of vehicle components...) to PM10 in an urban site. The approach used source apportionment modelling by PMF (Positive Matrix Factorization) with a chemical data set including chemical tracers. These data are obtained thanks to filter samples collected during short-time periods (4h temporal resolution). This study also includes the simultaneous sampling of chemical species on an urban background site (Grenoble-Les Frênes, France) and on a roadside site (Grenoble-Echirolles, France). This combination leads to accurate determination of traffic indicators sources. Finally, the source apportionment using PMF applied to this database gives possible contribution of sources to PM10. Results show that the road traffic source contribution to PM10 (exhaust + non-exhaust sources) was on average 34% and ranged from about 57% during the rush hours to 14% during less busy periods. Non-exhaust contribution is on average equivalent to the exhaust one.L'objectif de cette étude est de tester une méthodologie permettant de déterminer les contributions respectives aux teneurs atmosphériques en PM10 des émissions Îhiculaires à l'échappement et hors échappement (abrasion des freins, des pneus et de la route, remise en suspension des poussières de la chaussée...) dans un milieu urbain. La stratégie adoptée est d'appliquer une méthode de déconvolution des sources par un modèle statistique d'analyses multivariées (PMF, Positive Matrix Factorization) sur un jeu de données chimiques obtenues avec des filtres collectés sur des durées réduites (4h) et comprenant des traceurs spécifiques. Les prélèvements ont été réalisés simultanément sur un site de fond urbain (Grenoble-Les Frênes, France) et sur un site de proximité automobile (Grenoble-Échirolles, France). La discrimination des sources et la quantification de leur contribution par PMF sont ensuite obtenues sur la base de données établie. Les résultats montrent que les émissions Îhiculaires à l'échappement et hors échappement contribuent en moyenne à 34 % des PM10 et jusqu'à 57 % durant les heures de pointe, contre seulement 14 % durant les heures creuses. Sur la période de mesure, les émissions hors échappement sont en moyenne équivalentes aux émissions à l'échappement pour le site d'étude de proximité trafic

Urban case studies : general discussion

Urban case studies: general discussio

An Induced Mutation in Tomato eIF4E Leads to Immunity to Two Potyviruses

BACKGROUND: The characterization of natural recessive resistance genes and Arabidopsis virus-resistant mutants have implicated translation initiation factors of the eIF4E and eIF4G families as susceptibility factors required for virus infection and resistance function. METHODOLOGY/PRINCIPAL FINDINGS: To investigate further the role of translation initiation factors in virus resistance we set up a TILLING platform in tomato, cloned genes encoding for translation initiation factors eIF4E and eIF4G and screened for induced mutations that lead to virus resistance. A splicing mutant of the eukaryotic translation initiation factor, S.l_eIF4E1 G1485A, was identified and characterized with respect to cap binding activity and resistance spectrum. Molecular analysis of the transcript of the mutant form showed that both the second and the third exons were miss-spliced, leading to a truncated mRNA. The resulting truncated eIF4E1 protein is also impaired in cap-binding activity. The mutant line had no growth defect, likely because of functional redundancy with others eIF4E isoforms. When infected with different potyviruses, the mutant line was immune to two strains of Potato virus Y and Pepper mottle virus and susceptible to Tobacco each virus. CONCLUSIONS/SIGNIFICANCE: Mutation analysis of translation initiation factors shows that translation initiation factors of the eIF4E family are determinants of plant susceptibility to RNA viruses and viruses have adopted strategies to use different isoforms. This work also demonstrates the effectiveness of TILLING as a reverse genetics tool to improve crop species. We have also developed a complete tool that can be used for both forward and reverse genetics in tomato, for both basic science and crop improvement. By opening it to the community, we hope to fulfill the expectations of both crop breeders and scientists who are using tomato as their model of study

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/)

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Do child pedestrians deliberately take risks when they are in a hurry? An experimental study on a simulator

International audienc

Caractérisation et impacts des émissions de polluants du transport routier (Apports méthodologiques et cas d'études en Rhône Alpes.)

L'impact des particules fines (PM10-PM2.5) sur la santé a été largement étudié depuis de nombreuses années, notamment pour les sites de proximité automobile. De nombreux dépassements de la valeur limite en PM10 imposée par les directives européennes ont lieu en France et en Europe, en milieu urbain et plus fréquemment en proximité automobile. Les émissions véhiculaires sont une des sources majeures de particules. Ces émissions proviennent à la fois des échappements (TE) mais aussi des émissions hors échappement (TNE) (abrasion des freins, des pneus et de la route, resuspension des poussières de la chaussée dû au déplacement des véhicules ). En France, très peu d'études en proximité automobile ont été effectuées. Les études de déconvolution des sources en France et en Europe s'appuient la plupart du temps sur des parcs automobiles non adaptés (parc américain) ou trop anciens. De plus, seule la source TE est considérée, ce qui sous-estime largement la contribution véhiculaire aux PM10. La meilleure connaissance de la formation, de la caractérisation et de la quantification des particules émises par le trafic est devenue primordiale. L'objectif final étant la détermination des contributions des émissions véhiculaires TE et TNE aux sources primaires de particules, la caractérisation précise de ces sources est primordial. Pour cela, la recherche de traceurs véhiculaires en phases gaz et particulaire a constitué une grosse partie de ce travail. La combinaison de l'étude sur banc à rouleau de cinq véhicules bien représentés dans le parc automobile roulant français et de l'étude effectuée en proximité automobile (Rocade Sud de Grenoble) a constitué le socle de ce travail. Dans la première étude, certains composés chimiques sont apparus comme indicateurs des émissions TE (EC, HAP légers, profils d'alcanes typiques, quelques métaux comme Fe, Cu etc.). Des différences importantes sont observées entre les véhicules diesel sans filtre à particules (FAP) et les véhicules essence et diesel sans FAP. La seconde étude, comparant le site trafic (Grenoble-Echirolles) avec un site de fond urbain (Grenoble- Les Frênes), a mis en évidence certains composés chimiques comme spécifiques des sources TNE et TE sur la base des connaissances acquises avec les mesures sur banc et sur l'enrichissement de certains composés par rapport au site de fond (EC, Cu, Fe, Sn, Mn ). On peut souligner certains enrichissements majeurs comme EC (78%), Cu (82%), Fe (88%), etc. La résolution temporelle a été faite sur une base de 4h, permettant ainsi une caractérisation chimique détaillée en fonction des heures de pointe et "creuses". Une troisième étude, en site trafic également (Grenoble-Le Rondeau) mais sous influence du salage en hiver, est venue compléter nos recherches. Enfin, en nous appuyant sur les résultats de la première partie, nous avons cherché à déconvoluer les sources véhiculaires TE et TNE (Echirolles et Le Rondeau) au moyen d'un modèle statistique d'analyses multivariées, la PMF (Positive Matrix Factorization), apportant ainsi la contribution possible de ces sources aux PM10. Les émissions véhiculaires (TNE+ TE) y contribuent à 34% à Echirolles et à 53% au Rondeau. Quelques incertitudes sont discutées par rapport aux résultats trouvés avec ceux provenant de l'étude géochimique détaillée en première partie.Fine particles (PM10-P2.5) are recognized to be deleterious to human health particularly in the roadway vicinity. In European countries, and in particular in France, the European daily limit value is exceeded in many sites more than 35 times a year. One of the major sources of fine particles in urban and roadside sites is road traffic. Emissions from road traffic involve exhaust and non-exhaust emissions (resuspension of road dusts, from the brakes, tyres and road-surface-wear, from the corrosion of vehicle components ). Numerous studies have been performed in order to account for exhaust emissions, however not in France. Generally, the profiles used in source apportionment models are not adapted (since they are American profiles) to the French or European fleets. In addition, the contribution of the nonexhaust fraction to total particulate matter (PM) mass is generally not accounted for in the source apportionment results. Therefore, PM10 emissions are underestimated. As a result, better knowledge about formation, characterization and quantification of particles from traffic are becoming necessary. The goals of this work are numerous because ambient air and exhaust emission measurements have been involved. The aim is to accurately discriminate exhaust and nonexhaust sources, in order to provide groundbreaking insights into the contribution and chemical composition of traffic sources. Therefore, the analyses of gas and particle tracers represent a big part of this work. The relationships between the measurements of 5 in-use vehicles well-represented in the French fleet and measurements performed in the vicinity of a suburban highway (southern ring road of Grenoble) have been firstly examined. In the first study, several chemical compounds, organics and inorganics, appeared as tracers of vehicular exhaust (EC, light PAHs, typical alkanes profiles, metals like Fe, Cu etc.). Large differences are noticeable between Diesel vehicles without DPF and petrol vehicles/diesel vehicle retrofitted with a DPF. In the second study, comparison with results from an urban background site (Grenoble-Les Frênes) and from the traffic site (Grenoble-Echirolles) highlighted several specific chemical compounds of exhaust and non-exhaust sources (EC, Cu, Fe, Sn, Mn ). Large increments due to the local traffic have been observed (EC (+78%), Cu (82%), Fe (88%), etc.). The 4-hour temporal resolution allowed for the detailed characterization of chemical species during rush hours and less busy periods. An additional field campaign was performed in another roadside site (Grenoble-Le Rondeau) but in winter during salting conditions. Supplementary information was obtained concerning non-exhaust sources. Finally, thanks to the results from the first part of this work, a Positive Matrix Factorization (PMF) analysis was applied to roadside data (Echirolles and Le Rondeau) in order to discriminate non-exhaust and exhaust traffic sources and to estimate their contribution to PM10. Major contributions for traffic sources (exhaust and non-exhaust) were 34% (Echirolles) and 53% (Le Rondeau). Uncertainties linked to these results are discussed with the results of the first part (detailed chemical study) of this work.SAVOIE-SCD - Bib.électronique (730659901) / SudocGRENOBLE1/INP-Bib.électronique (384210012) / SudocGRENOBLE2/3-Bib.électronique (384219901) / SudocSudocFranceF

Receptor modelling of secondary and carbonaceous particulate matter at a southern UK site

Complementary approaches have been taken to better understand the sources and their spatial distribution for secondary inorganic (nitrate and sulphate) and secondary organic aerosol sampled at a rural site (Harwell) in the southern United Kingdom. A concentration field map method was applied to 1581 daily samples of chloride, nitrate and sulphate from 2006 to 2010, and 982 samples for organic carbon and elemental carbon from 2007 to 2010. This revealed a rather similar pattern of sources for nitrate, sulphate and secondary organic carbon within western/central Europe, which in the case of nitrate, sulphate, organic carbon and secondary organic carbon, correlated significantly with EMEP emissions maps of NOx, SO2, and VOC respectively. A slightly more southerly source emphasis for secondary organic carbon may reflect the contribution of biogenic sources. Trajectory clusters confirm this pattern of behaviour with a major contribution from mainland European sources. Similar behaviours of, on the one hand, sulphate and organic carbon and, on the other hand, EC and nitrate showed that the former are more subject to regional influence than the latter in agreement with the slower atmospheric formation of sulphate and secondary organic aerosol than for nitrate, and the local/mesoscale influences upon primary EC. However, careful analysis of back trajectories and Concentration Field Maps indicates a strong contribution of mainland European sites to EC concentrations at Harwell. In a separate study, measurements of sulphate, nitrate, elemental and organic carbon were made in 100 simultaneously collected samples at Harwell and at a suburban site in Birmingham (UK). This showed a significant correlation in concentrations between the two sites for all of the secondary constituents, further indicating secondary organic aerosol to be a regional pollutant behaving similarly to sulphate and nitrate

Syndrome du choc toxique staphylococcique après chirurgie du sein

International audienceThe surgical site infection occurs within 30 days after surgery. It is the most common complication of surgery, with a rate of 1 to 5% without antibiotic prophylaxis and less than 1% with antibiotic prophylaxis. The toxic shock syndrome (TSS) is a dramatic complication. We report the case 39-year-old woman who presented a life-threatening TSS acquired after breast surgery. We describe the signs and symptoms of this condition as well as treatment principles