Modeling the effect of packing density on filtration performances in hollow fiber microfiltration module: a spatial study of cake growth

This study continues from a previous work on the impact of packing density on the fluid flow distribution in a hollow fiber module [1]. A numerical model was developed to simulate the growth of a particle cake along the surface of a hollow fiber membrane and the subsequent fluid flow during a microfiltration operation. The model accounts for the continuous change in porous domain (cake and porous wall) geometry and permeability as long as filtration occurs. The effect module packing density has upon cake growth is carefully analyzed both for inside/out (I/O) and outside/in (O/I) filtration modes. The results exhibit significant differences in the time variations of cake spatial distribution along the fiber as a function of packing density for both filtration modes. Then a confrontation between forward filtration and backward filtration velocities offers some conclusion on the effect of packing density on the backwash efficiency. This in turn underlines the importance of design parameters in the filtration performance of a hollow fiber module

Latrodectism in New Caledonia : first report of presumed redback spider (Latrodectus hasselti) envenomation

We describe a recent case of presumed redback spider (Latrodectus hasselti) envenomation observed near Noumea in New Caledonia. This is the first local reported case in this archipelago, where L. hasselti is Currently considered a native species. We highlight the challenge of providing appropriate analgesia in this situation and believe that the use of specific redback spider antivenom should be considered in New Caledonia

Benchmarking proton exchange membrane fuel cell cathode catalyst at high current density: a comparison between the rotating disk electrode, the gas diffusion electrode and differential cell

International audienceThe intrinsic activity of oxygen reduction reaction (ORR) electrocatalysts for proton exchange membrane fuel cell (PEMFC) is usually evaluated with the rotating disk electrode (RDE), an easy-to-use technique requiring little amount of electrocatalyst. However, the liquid environment of the RDE implies strong limitation of O2 mass-transport and the intrinsic activity is only accessible on a narrow potential range (from 0.95 to 0.85 V vs. RHE) that is not relevant for the PEMFC operating conditions. This work compares results obtained with the RDE (0.2 cm²), the gas diffusion electrode (GDE, 0.07 cm²) and a small unit PEMFC (DC, 1.8 cm²). Three widely used ORR electrocatalysts are compared: Pt/Vulcan carbon, PtCo/Vulcan carbon and Pt/graphitized carbon, catalytic layers being prepared with a loading of 20 µgPt cm-2 and characterized at 25-30°C and full hydration. The results show that all setups have their own advantages and drawbacks. Regardless the electrocatalyst nature, the GDE allows to assess the intrinsic activities on a large potential range (from 0.9 to 0.6 V), in agreement with the results obtained in RDE for high potential and with the DC for lower potential. The GDE is therefore promising, enabling easy high current density measurements with little amount of electrocatalyst

Autopsies de petites installations d'assainissement. Démantèlement de 5 des 8 filières testées sur la plateforme du CSTB dans le cadre de l'étude comparative Veolia Eau (1ère partie)

National audienceÀ l'issue de 3 ans d'alimentation en conditions connues, 5 filières d'assainissement autonome sont mises à l'arrêt. Avant de les démanteler et de libérer le site d'étude, il a semblé opportun de réaliser un état des lieux de ces dispositifs. L'idée a été d'identifier ce qui pouvait être mis en évidence au cours d'une telle intervention, dans l'optique de réalisation de diagnostics de fin de vie, ou de diagnostics de dysfonctionnement. Un protocole de démantèlement a été adapté à chaque type de système autopsié. Cette première vague d'autopsie a apporté des enseignements particulièrement intéressants sur le fonctionnement des systèmes extensifs, ainsi que plus globalement d'ordre méthodologique. Ils pourront être utilement complétés lors de la mise hors service des 3 dispositifs encore en place sur la plateforme du CSTB à Nantes, prévue en septembre 2010

Benchmarking proton exchange membrane fuel cell cathode catalyst at high current density: a comparison between the rotating disk electrode, the gas diffusion electrode and differential cell

International audienceThe intrinsic activity of oxygen reduction reaction (ORR) electrocatalysts for proton exchange membrane fuel cell (PEMFC) is usually evaluated with the rotating disk electrode (RDE), an easy-to-use technique requiring little amount of electrocatalyst. However, the liquid environment of the RDE implies strong limitation of O2 mass-transport and the intrinsic activity is only accessible on a narrow potential range (from 0.95 to 0.85 V vs. RHE) that is not relevant for the PEMFC operating conditions. This work compares results obtained with the RDE (0.2 cm²), the gas diffusion electrode (GDE, 0.07 cm²) and a small unit PEMFC (DC, 1.8 cm²). Three widely used ORR electrocatalysts are compared: Pt/Vulcan carbon, PtCo/Vulcan carbon and Pt/graphitized carbon, catalytic layers being prepared with a loading of 20 µgPt cm-2 and characterized at 25-30°C and full hydration. The results show that all setups have their own advantages and drawbacks. Regardless the electrocatalyst nature, the GDE allows to assess the intrinsic activities on a large potential range (from 0.9 to 0.6 V), in agreement with the results obtained in RDE for high potential and with the DC for lower potential. The GDE is therefore promising, enabling easy high current density measurements with little amount of electrocatalyst

Platon aujourd’hui

Loin de diminuer à l’orée du troisième millénaire, le nombre des études spécialisées sur Platon, son œuvre et sa philosophie ne cesse d’augmenter. Pourquoi cet engouement pour un philosophe que deux millénaires et demi séparent de nous ? De quelle signification et de quelle portée est la philosophie platonicienne pour le monde d’aujourd’hui ? Qu’il s’agisse de questions épistémologiques, de réflexion sur les mathématiques, la physique, la cosmologie ; qu’il s’agisse encore de politique et d’éthique, voire d’esthétique et de littérature, nombreux sont aujourd’hui dans tous ces domaines ceux qui, d’une façon ou d’une autre, à un titre ou à un autre, se réfèrent à Platon. « Platon aujourd’hui » a donc pour ambition de donner l’occasion à des participants venus de tous ces horizons d’expliciter et de confronter leurs visions de Platon, de son œuvre et de sa philosophie : qu’entend-on aujourd’hui par « platonisme » ? Ce numéro a été publié avec le concours de la Région Île-de-France, du CNRS (Département S.H.S.) et de l’université Paris Ouest (ArScAn - Themam ED 139, ED 395)

Hydrocortisone plus fludrocortisone for community acquired pneumonia-related septic shock: a subgroup analysis of the APROCCHSS phase 3 randomised trial

International audienceBackground: Glucocorticoids probably improve outcomes in patients hospitalised for community acquired pneumonia (CAP). In this a priori planned exploratory subgroup analysis of the phase 3 randomised controlled Activated Protein C and Corticosteroids for Human Septic Shock (APROCCHSS) trial, we aimed to investigate responses to hydrocortisone plus fludrocortisone between CAP and non-CAP related septic shock.Methods: APROCCHSS was a randomised controlled trial that investigated the effects of hydrocortisone plus fludrocortisone, drotrecogin-alfa (activated), or both on mortality in septic shock in a two-by-two factorial design; after drotrecogin-alfa was withdrawn on October 2011, from the market, the trial continued on two parallel groups. It was conducted in 34 centres in France. In this subgroup study, patients with CAP were a preselected subgroup for an exploratory secondary analysis of the APROCCHSS trial of hydrocortisone plus fludrocortisone in septic shock. Adults with septic shock were randomised 1:1 to receive, in a double-blind manner, a 7-day treatment with daily administration of intravenous hydrocortisone 50 mg bolus every 6h and a tablet of 50 μg of fludrocortisone via the nasogastric tube, or their placebos. The primary outcome was 90-day all-cause mortality. Secondary outcomes included all-cause mortality at intensive care unit (ICU) and hospital discharge, 28-day and 180-day mortality, the number of days alive and free of vasopressors, mechanical ventilation, or organ failure, and ICU and hospital free-days to 90-days. Analysis was done in the intention-to-treat population. The trial was registered at ClinicalTrials.gov (NCT00625209).Findings: Of 1241 patients included in the APROCCHSS trial, CAP could not be ruled in or out in 31 patients, 562 had a diagnosis of CAP (279 in the placebo group and 283 in the corticosteroid group), and 648 patients did not have CAP (329 in the placebo group and 319 in the corticosteroid group). In patients with CAP, there were 109 (39%) deaths of 283 patients at day 90 with hydrocortisone plus fludrocortisone and 143 (51%) of 279 patients receiving placebo (odds ratio [OR] 0·60, 95% CI 0·43-0·83). In patients without CAP, there were 148 (46%) deaths of 319 patients at day 90 in the hydrocortisone and fludrocortisone group and 157 (48%) of 329 patients in the placebo group (OR 0·95, 95% CI 0·70-1·29). There was significant heterogeneity in corticosteroid effects on 90-day mortality across subgroups with CAP and without CAP (p=0·046 for both multiplicative and additive interaction tests; moderate credibility). Of 1241 patients included in the APROCCHSS trial, 648 (52%) had ARDS (328 in the placebo group and 320 in the corticosteroid group). There were 155 (48%) deaths of 320 patients at day 90 in the corticosteroid group and 186 (57%) of 328 patients in the placebo group. The OR for death at day 90 was 0·72 (95% CI 0·53-0·98) in patients with ARDS and 0·85 (0·61-1·20) in patients without ARDS (p=0·45 for multiplicative interaction and p=0·42 for additive interaction). The OR for observing at least one serious adverse event (corticosteroid group vs placebo) within 180 days post randomisation was 0·64 (95% CI 0·46-0·89) in the CAP subgroup and 1·02 (0·75-1·39) in the non-CAP subgroup (p=0·044 for multiplicative interaction and p=0·042 for additive interaction).Interpretation: In a pre-specified subgroup analysis of the APROCCHSS trial of patients with CAP and septic shock, hydrocortisone plus fludrocortisone reduced mortality as compared with placebo. Although a large proportion of patients with CAP also met criteria for ARDS, the subgroup analysis was underpowered to fully discriminate between ARDS and CAP modifying effects on mortality reduction with corticosteroids. There was no evidence of a significant treatment effect of corticosteroids in the non-CAP subgroup.Funding: Programme Hospitalier de Recherche Clinique of the French Ministry of Health, by Programme d'Investissements d'Avenir, France 2030, and IAHU-ANR-0004

Severity of COVID-19 and survival in patients with rheumatic and inflammatory diseases: data from the French RMD COVID-19 cohort of 694 patients

International audienceObjectives: There is little known about the impact of SARS-CoV-2 on patients with inflammatory rheumatic and musculoskeletal diseases (iRMD). We examined epidemiological characteristics associated with severe disease, then with death. We also compared mortality between patients hospitalised for COVID-19 with and without iRMD.Methods: Individuals with suspected iRMD-COVID-19 were included in this French cohort. Logistic regression models adjusted for age and sex were used to estimate adjusted ORs and 95% CIs of severe COVID-19. The most significant clinically relevant factors were analysed by multivariable penalised logistic regression models, using a forward selection method. The death rate of hospitalised patients with iRMD-COVID-19 (moderate-severe) was compared with a subset of patients with non-iRMD-COVID-19 from a French hospital matched for age, sex, and comorbidities.Results: Of 694 adults, 438 (63%) developed mild (not hospitalised), 169 (24%) moderate (hospitalised out of the intensive care unit (ICU) and 87 (13%) severe (patients in ICU/deceased) disease. In multivariable imputed analyses, the variables associated with severe infection were age (OR=1.08, 95% CI: 1.05-1.10), female gender (OR=0.45, 95% CI: 0.25-0.80), body mass index (OR=1.07, 95% CI: 1.02-1.12), hypertension (OR=1.86, 95% CI: 1.01-3.42), and use of corticosteroids (OR=1.97, 95% CI: 1.09-3.54), mycophenolate mofetil (OR=6.6, 95% CI: 1.47-29.62) and rituximab (OR=4.21, 95% CI: 1.61-10.98). Fifty-eight patients died (8% (total) and 23% (hospitalised)). Compared with 175 matched hospitalised patients with non-iRMD-COVID-19, the OR of mortality associated with hospitalised patients with iRMD-COVID-19 was 1.45 (95% CI: 0.87-2.42) (n=175 each group).Conclusions: In the French RMD COVID-19 cohort, as already identified in the general population, older age, male gender, obesity, and hypertension were found to be associated with severe COVID-19. Patients with iRMD on corticosteroids, but not methotrexate, or tumour necrosis factor alpha and interleukin-6 inhibitors, should be considered as more likely to develop severe COVID-19. Unlike common comorbidities such as obesity, and cardiovascular or lung diseases, the risk of death is not significantly increased in patients with iRMD

Severity of COVID-19 and survival in patients with rheumatic and inflammatory diseases: data from the French RMD COVID-19 cohort of 694 patients

International audienceObjectives: There is little known about the impact of SARS-CoV-2 on patients with inflammatory rheumatic and musculoskeletal diseases (iRMD). We examined epidemiological characteristics associated with severe disease, then with death. We also compared mortality between patients hospitalised for COVID-19 with and without iRMD.Methods: Individuals with suspected iRMD-COVID-19 were included in this French cohort. Logistic regression models adjusted for age and sex were used to estimate adjusted ORs and 95% CIs of severe COVID-19. The most significant clinically relevant factors were analysed by multivariable penalised logistic regression models, using a forward selection method. The death rate of hospitalised patients with iRMD-COVID-19 (moderate-severe) was compared with a subset of patients with non-iRMD-COVID-19 from a French hospital matched for age, sex, and comorbidities.Results: Of 694 adults, 438 (63%) developed mild (not hospitalised), 169 (24%) moderate (hospitalised out of the intensive care unit (ICU) and 87 (13%) severe (patients in ICU/deceased) disease. In multivariable imputed analyses, the variables associated with severe infection were age (OR=1.08, 95% CI: 1.05-1.10), female gender (OR=0.45, 95% CI: 0.25-0.80), body mass index (OR=1.07, 95% CI: 1.02-1.12), hypertension (OR=1.86, 95% CI: 1.01-3.42), and use of corticosteroids (OR=1.97, 95% CI: 1.09-3.54), mycophenolate mofetil (OR=6.6, 95% CI: 1.47-29.62) and rituximab (OR=4.21, 95% CI: 1.61-10.98). Fifty-eight patients died (8% (total) and 23% (hospitalised)). Compared with 175 matched hospitalised patients with non-iRMD-COVID-19, the OR of mortality associated with hospitalised patients with iRMD-COVID-19 was 1.45 (95% CI: 0.87-2.42) (n=175 each group).Conclusions: In the French RMD COVID-19 cohort, as already identified in the general population, older age, male gender, obesity, and hypertension were found to be associated with severe COVID-19. Patients with iRMD on corticosteroids, but not methotrexate, or tumour necrosis factor alpha and interleukin-6 inhibitors, should be considered as more likely to develop severe COVID-19. Unlike common comorbidities such as obesity, and cardiovascular or lung diseases, the risk of death is not significantly increased in patients with iRMD

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