Influence of the thermophoresis on aerosol deposition on warm urban surfaces

International audienceIn the case of an accidental or chronic atmospheric pollution by a nuclear plant, aerosols' deposition transfer coefficients must be known. A major issue is to determine the impact of aerosols contained in the radioactive plume on urban areas with the smallest uncertainties

Determinants of bacterial survival and proliferation in blood

International audienceBloodstream infection is a major public health concern associated with high mortality and high healthcare costs worldwide. Bacteremia can trigger fatal sepsis whose prevention, diagnosis and management have been recognized as a global health priority by the World Health Organization. Additionally, infection control is increasingly threatened by antimicrobial resistance, which is the focus of global action plans in the framework of a One Health response. In-depth knowledge of the infection process is needed to develop efficient preventive and therapeutic measures. The pathogenesis of bloodstream infection is a dynamic process resulting from the invasion of the vascular system by bacteria, which finely regulate their metabolic pathways and virulence factors to overcome the blood immune defenses and proliferate. In this review, we highlight our current understanding of determinants of bacterial survival and proliferation in the bloodstream and discuss their interactions with the molecular and cellular components of blood

Beachrocks and lithified barriers in the Gulf of Lions (western Mediterranean Sea) as new markers of the last sea-level rise

The Gulf of Lions shelf (southern part of the French Mediterranean coast) displays several occurrences of beachrocks, thus offering an exceptional opportunity to determine the stages of the last marine transgression. These beachrocks crop out especially on the outer shelf and near the modern shoreline. In addition, several other exposures are located on the inner shelf between 10 m and 25 m). The absence of exposure on the middle shelf (water depths of 25 to 90 m) is probably related to a higher rate of sea-level rise. Most of the beachrocks occur at the top of two or three parallel and contiguous barriers. The seaward barriers are generally less lithified than the inner barriers. Each barrier displays an asymmetric profile, the seaward slope being more accentuated. This gently-dipping landward slope forms part of the outer trough resulting from resuspension due to enhanced turbulence at the barrier toe. Almost all of these beachrocks are coarse quartz-rich sandstones and conglomerates, whose large pore space has been first filled by magnesian calcite (ca 11 mol.% MgCO3), which predominantly fills the voids. Secondary sparites or microsparites, also composed of high-magnesian calcite, may develop locally in the last remaining voids. Finally, more rarely and very locally (for example, Pierres de Sète), a late-stage cementation of low-magnesian calcite is observed which expresses a brief episode of influence from a nearby freshwater groundwater table. δ18O and δ13C values reflect the relative geochemical homogeneity of these Gulf of Lions beachrocks. However, they are quite distinct from other marine cements, and in particular, those of the eastern Mediterranean, expressing lower temperatures and a lack of influence of dissolved carbon linked to terrigenous fluxes. Based on the radiocarbon ages of these calcitic cements, this study proposes new index points on sea-level positions in the Gulf of Lions from -95 to 108 m to -0.3 m water depths, between ca 18,583 a cal BP and 633 a cal BP

Influence of the thermophoresis on aerosol deposition on warm urban surfaces

International audienceIn the case of an accidental or chronic atmospheric pollution by a nuclear plant, aerosols' deposition transfer coefficients must be known. A major issue is to determine the impact of aerosols contained in the radioactive plume on urban areas with the smallest uncertainties

Rapid identification of Erwinia amylovora and Pseudomonas syringae species and characterization of E. amylovora streptomycin resistance using quantitative PCR assays

Erwinia amylovora and Pseudomonas syringae are bacterial phytopathogens responsible for considerable yield losses in commercial pome fruit production. The pathogens, if left untreated, can compromise tree health and economically impact entire commercial fruit productions. Historically, the choice of effective control methods has been limited. The use of antibiotics was proposed as an effective control method. The identification of these pathogens and screening for the presence of antibiotic resistance is paramount in the adoption and implementation of the disease control methods. Molecular tests have been developed and accepted for identification and characterization of these disease-causing organisms. We improved existing molecular tests by developing methods that are equal or superior in the robustness for the identification of either E. amylovora or P. syringae while being faster to execute. In addition, the real-time PCR based detection method for E. amylovora provided complementary information on streptomycin susceptibility or resistance of individual isolates. Finally, we describe a methodology and results that compare the aggressiveness of the different bacterial isolates on four apple cultivars. We show that bacterial isolates have different behaviors when put in contact with various apple varieties and, hierarchical clustering on the severity of the symptoms indicates a population structure, suggesting a genetic basis for host cultivar specificity.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Impact of temporal beach grain size variability on aeolian sediment transport and topographic evolution in a microtidal environment

While the impact of the spatio/temporal variability of grain size on morphological beach state is reasonably well understood, relatively little is known on its impact at a scale of days/months on aeolian sediment transport. This study focuses on five short intensive wind events during which aeolian sediment transport measurements, beach surface sampling and elevation change surveys were carried out for 1 to 3 days, over a 16-month period on a microtidal beach dominated by offshore winds. Monthly observations show a high temporal variability in beach grain size in relation to the decoupling between hydrodynamic and aeolian processes, from medium sand after a marine storm and inundation of the beach, to very coarse sand after several weeks of storm-force winds. During each wind event, topographic change on the beach ranged from zero, to 0.55 m. The time scale of coarsening depended on the initial beach grain size and could be very fast when the beach was composed of medium sand (e.g. 388 μm sand changed to coarse sand of 547 μm in 40 h). In contrast, it took one month to transition from a coarse median beach grain size of 883 μm to a very coarse one of 1323 μm. This variability in grain size results in dramatically different rates of sediment flux. For example, during average wind speeds of 10 to 14 m/s the sediment flux when the beach was composed of medium sized sand ranged between 21 and 154 kg/m/h compared to 0.4 to 50 kg/m/h when the beach was composed of coarse and very coarse sized grains. Overall, this study highlights the importance of beach grain size variability on aeolian sediment transport and shows that for similar incident wind and climatic conditions aeolian sediment transport rates vary dramatically. The study demonstrates the importance of taking care when using a constant median grain size in the calculation of long-term aeolian sand transport on beaches with heterogeneous spatial and temporal beach grain size variability

Study of atmospheric dispersion under low wind conditions in an urban environment, first results

International audienceAll atmospheric conditions must be considered in the impact calculation of industrial facilities. In low wind conditions (wind speed below 2m.s-1), the meandering (low frequency horizontal wind oscillation) becomes one of the predominant physical processes which drive atmospheric dispersion of pollutants. Experimentally, it can be identified by analyzing the autocorrection function of the horizontal wind speed components. However, modeling these situations is more complicated, and most models are unable to correctly reproduce the turbulent flow structure and the resulting plume dispersion. The CFD models could overcome these limits by adapting the existing modeling approaches to low wind speed situations. In this study, we present the first analyses of datasets from an experimental campaign that has been performed at SIRTA in the south of Paris in 2020 as well as first simulation results obtained with a CFD model using two different modelling approaches: stationary and pseudo stationary conditions. The analysis of wind data acquired during one selected time period of the campaign allowed to identify the presence of meandering and to estimate its period. Compared to concentration measurements, the first modelling approach seems to lower lateral dispersion while the second approach seems to give closer results

Conservative management or cesarean hysterectomy for placenta accreta spectrum ::the PACCRETA prospective study

Background : Placenta accreta spectrum is a life-threatening condition that has increased dramatically in recent decades along with cesarean rates worldwide. Cesarean hysterectomy is widely practiced in women with placenta accreta spectrum; however, the maternal outcomes after cesarean hysterectomy have not been thoroughly compared with the maternal outcomes after alternative approaches, such as conservative management. Objective : This study aimed to compare the severe maternal outcomes between women with placenta accreta spectrum treated with cesarean hysterectomy and those treated with conservative management (leaving the placenta in situ). Study Design : From a source population of 520,114 deliveries in 176 hospitals (PACCRETA study), we designed an observational cohort of women with placenta accreta spectrum who had either a cesarean hysterectomy or a conservative management (the placenta left in situ) during cesarean delivery. Clinicians prospectively identified women meeting the inclusion criteria and included them at delivery. Data collection started only after the women had received information and agreed to participate in the study in the immediate postpartum period. The primary outcome was the transfusion of >4 units of packed red blood cells within 6 months after delivery. Secondary outcomes were other maternal complications within 6 months. We used propensity score weighting to account for potential indication bias. Results : Here, 86 women had conservative management and 62 women had cesarean hysterectomy for placenta accreta spectrum during cesarean delivery. The primary outcome occurred in 14 of 86 women in the conservative management group (16.3%) and 36 of 61 (59.0%) in the cesarean hysterectomy group (risk ratio in propensity score weighted model, 0.29; 95% confidence interval, 0.19–0.45). The rates of hysterectomy, total estimated blood loss exceeding 3000 mL, any blood product transfusion, adjacent organ injury, and nonpostpartum hemorrhage-related severe maternal morbidity were lower with conservative management than with cesarean hysterectomy (all adjusted, P≤.02); but, the rates of arterial embolization, endometritis, and readmission within 6 months of discharge were higher with conservative management than with cesarean hysterectomy. Conclusion : Among women with placenta accreta spectrum who underwent cesarean delivery, conservative management was associated with a lower risk of transfusion of >4 units of packed red blood cells within 6 months than cesarean hysterectomy

Risk factors for placenta accreta spectrum disorders in women with any prior cesarean and a placenta previa or low lying: a prospective population-based study

International audienceThis study aimed to identify the risk factors for placenta accreta spectrum (PAS) in women who had at least one previous cesarean delivery and a placenta previa or low-lying. The PACCRETA prospective population-based study took place in 12 regional perinatal networks from 2013 through 2015. All women with one or more prior cesareans and a placenta previa or low lying were included. Placenta accreta spectrum (PAS) was diagnosed at delivery according to standardized clinical and histological criteria. Of the 520,114 deliveries, 396 fulfilled inclusion criteria; 108 were classified with PAS at delivery. Combining the number of prior cesareans and the placental location yielded a rate ranging from 5% for one prior cesarean combined with a posterior low-lying placenta to 63% for three or more prior cesareans combined with placenta previa. The factors independently associated with PAS disorders were BMI ≥ 30, previous uterine surgery, previous postpartum hemorrhage, a higher number of prior cesareans, and a placenta previa. Finally, in this high-risk population, the rate of PAS disorders varies greatly, not only with the number of prior cesareans but also with the exact placental location and some of the women's individual characteristics. Risk stratification is thus possible in this population

Desmosomal gene analysis in arrhythmogenic right ventricular dysplasia/cardiomyopathy: spectrum of mutations and clinical impact in practice.

International audienceAIMS: Five desmosomal genes have been recently implicated in arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) but the clinical impact of genetics remains poorly understood. We wanted to address the potential impact of genotyping. METHODS AND RESULTS: Direct sequencing of the five genes (JUP, DSP, PKP2, DSG2, and DSC2) was performed in 135 unrelated patients with ARVD/C. We identified 41 different disease-causing mutations, including 28 novel ones, in 62 patients (46%). In addition, a genetic variant of unknown significance was identified in nine additional patients (7%). Distribution of genes was 31% (PKP2), 10% (DSG2), 4.5% (DSP), 1.5% (DSC2), and 0% (JUP). The presence of desmosomal mutations was not associated with familial context but was associated with young age, symptoms, electrical substrate, and extensive structural damage. When compared with other genes, DSG2 mutations were associated with more frequent left ventricular involvement (P = 0.006). Finally, complex genetic status with multiple mutations was identified in 4% of patients and was associated with more frequent sudden death (P = 0.047). CONCLUSION: This study supports the use of genetic testing as a new diagnostic tool in ARVC/D and also suggests a prognostic impact, as the severity of the disease appears different according to the underlying gene or the presence of multiple mutations