Granulation sèche des poudres : Influence des paramètres du procédé

National audienceDans un but d'optimisation du procédé de granulation sèche de poudres, une presse à rouleaux instrumentée a été développée. Une première campagne d'essais a permis de visualiser le profil des contraintes à la surface des rouleaux en fonction de l'angle de rotation, ainsi que l'allure des différents paramètres (couple, effort, entrefer) au cours de l'essai

Biological response to purification and acid functionalization of carbon nanotubes

The final publication is available at Springer via: http://link.springer.com/article/10.1007/s11051-014-2507-yInternational audienceAcid functionalization has been considered as an easy way to enhance the dispersion and biodegradation of carbon nanotubes (CNT). However, inconsistencies between toxicity studies of acid functionalized CNT remain unexplained. This could be due to a joint effect of the main physicochemical modifications resulting from an acid functionalization: addition of surface acid groups and purification from catalytic metallic impurities. In this study, the impact on CNT biotoxicity of these two physiochemical features was assessed separately. The in vitro biological response of RAW 264.7 macrophages was evaluated after exposure to 15-240 µg x mL−1 of two types of multi-walled CNT. For each type of CNT (small: 20 nm diameter, and big: 90 nm diameter), three different surface chemical properties were studied (total of six CNT samples): pristine, acid functionalized and desorbed. Desorbed CNT were purified by the acid functionalization but presented a very low amount of surface acid groups due to a thermal treatment under vacuum. A Janus effect of acid functionalization with two opposite impacts is highlighted. The CNT purification decreased the overall toxicity, while the surface acid groups intensified it when present at a specific threshold. These acid groups especially amplified the pro-inflammatory response. The threshold mechanism which seemed to regulate the impact of acid groups should be further studied to determine its value and potential link to the other physicochemical state of the CNT. The results suggest that, for a safer-design approach, the benefit-risk balance of an acid functionalization has to be considered, depending on the CNT primary state of purification. Further research should be conducted in this direction

Influence de l'atmosphère gazeuse sur la cinétique de formation du titanate de baryum par réaction solide-solide

International audienceLes études consacrées à la synthèse, par réaction solide-solide, du titanate de baryum (BaTiO3) ont montré l'importance des propriétés physicochimiques des solides initiaux (BaCO3 et TiO2) sur les propriétés du titanate obtenu. Lors de l'élaboration de céramiques diélectriques, il est en effet nécessaire d'éviter la formation de phases intermédiaires (Ba2TiO4, BaTi4O9, ...) qui nuisent à leurs propriétés diélectriques. La présence de ces phases peut être liée à une maîtrise imparfaite des nombreux paramètres influant sur la cinétique de la réaction. Le rôle de deux de ces paramètres : les traitements mécaniques et la nature de l'atmosphère gazeuse, fait l'objet de ce travail

Thermal annealing of carbon nanotubes reveals a strong toxicological impact of the structural defects

Le document inséré dans cette page comprend des données supplémentaire à l'article " Thermal annealing of carbon nanotubes reveals a toxicological impact of the structural defects" (DOI: 10.1007/s11051-015-2999-0) paru dans Journal of Nanoparticles ResearchInternational audienceThe biological response to pristine and annealed multi-walled carbon nanotubes (MWCNT) was assessed on murine macrophages (RAW 264.7). First, the physicochemical features of the as-produced MWCNT and annealed at 2125 °C for 1 h were fully characterized. A decrease in structural defects, hydrophobicity and catalytic impurities was detected after annealing. Thereafter, their impact on cytotoxicity, oxidative stress, and pro-inflammatory response was investigated at concentrations ranging from 15 to 120 µg mL−1. No effect of the 2125 °C treatment was detected on the cytotoxicity. In contrast, the annealed carbon nanotubes showed a significant increase of the pro-inflammatory response. We assumed that this behavior was due to the reduction in structural defects that may modify the layer of adsorbed biomolecules. Surprisingly, the purification of metallic catalysts did not have any significant impact on the oxidative stress. We suggested that the structural improvements from the 2125 °C treatment can decrease the carbon nanotube scavenging capacity and thus allow a higher free radical release which may counterbalance the decrease of oxidative stress due to a lower content of metallic impurities

MR imaging of the metacarpophalangeal joints of the fingers: evaluation of 38 patients with chronic joint disability

Objective: To report the MR imaging findings of painful injured metacarpophalangeal (MCP) joints of the fingers. Design and patients: MR imaging of 39 injured MCP joints in 38 patients was performed after a mean delay of 8.8months. The MR images were obtained with the fingers in extended and flexed positions using T2-weighted and T1-weighted sequences before and after intravenous injection of a gadolinium compound. Ten patients were treated surgically. Mean clinical follow-up was 1.8years. Results: Tears of the collateral ligaments were the most common lesion (30/39), most being radial in location. Contrast-enhanced axial T1-weighted images with the MCP joint in a flexed position showed these lesions optimally. Ten tears were partial and 20 were complete. In 13 patients, MR images showed 17 associated lesions including injuries of the extensor hood (10/17), interosseous tendon (3/17), palmar plate (3/17), and an osteochondral lesion (1/17). Sagittal MR images were essential to highlight palmar plate tears. Conclusion: Partial or complete tears of the collateral ligaments are prevalent MR imaging findings in patients with chronic disability resulting from injuries to the MCP joints. Although conservative treatment generally is sufficient for isolated injuries of the collateral ligaments, surgical repair is often required in cases of more extensive injuries. MR imaging may clearly delineate associated lesions of and about the MCP joint

Staphylococcus aureus Bloodstream Infection and Endocarditis―A Prospective Cohort Study

Equipe CHU UB (EA) Pôle MERS CT3 Hors Enjeu The VIRSTA Study Group : Clinical centres: Besançon: Catherine Chirouze, Elodie Curlier, Cécile Descottes-Genon, Bruno Hoen, Isabelle Patry, Lucie Vettoretti. Dijon: Pascal Chavanet, Jean-Christophe Eicher, Sandrine Gohier-Treuvelot, Marie-Christine Greusard, Catherine Neuwirth, André Péchinot, Lionel Piroth. Lyon: Marie Célard, Catherine Cornu, François Delahaye, Malika Hadid, Pascale Rausch. Montpellier: Audrey Coma, Florence Galtier, Philippe Géraud, Hélène Jean-Pierre, Vincent Le Moing, Catherine Sportouch, Jacques Reynes. Nancy: Nejla Aissa, Thanh Doco- Lecompte, François Goehringer, Nathalie Keil, Lorraine Letranchant, Hepher Malela, Thierry May, Christine Selton-Suty. Nîmes: Nathalie Bedos, Jean-Philippe Lavigne, Catherine Lechiche, Albert Sotto. Paris: Xavier Duval, Emila Ilic Habensus, Bernard Iung, Catherine Leport, Pascale Longuet, Raymond Ruimy. Rennes: Eric Bellissant, Pierre-Yves Donnio, Fabienne Le Gac, Christian Michelet, Matthieu Revest, Pierre Tattevin, Elise Thebault. Coordination and statistical analyses: François Alla, Pierre Braquet, Marie-Line Erpelding, Laetitia Minary, Sarah Tubiana. Centre National de Référence des staphylocoques: Michèle Bès, Jérôme Etienne, Anne Tristan, François Vandenesch. Sponsor CHU de Montpellier: Sandrine Barbas, Christine Delonca, Virginie Sussmuth, Anne Verchère. Alain Makinson reviewed the manuscript for English correctness.International audienceOBJECTIVES: To update the epidemiology of S. aureus bloodstream infection (SAB) in a high-income country and its link with infective endocarditis (IE).METHODS: All consecutive adult patients with incident SAB (n = 2008) were prospectively enrolled between 2009 and 2011 in 8 university hospitals in France. RESULTS: SAB was nosocomial in 54%, non-nosocomial healthcare related in 18% and community-acquired in 26%. Methicillin resistance was present in 19% of isolates. SAB Incidence of nosocomial SAB was 0.159/1000 patients-days of hospitalization (95% confidence interval [CI] 0.111-0.219). A deep focus of infection was detected in 37%, the two most frequent were IE (11%) and pneumonia (8%). The higher rates of IE were observed in injecting drug users (IE: 38%) and patients with prosthetic (IE: 33%) or native valve disease (IE: 20%) but 40% of IE occurred in patients without heart disease nor injecting drug use. IE was more frequent in case of community-acquired (IE: 21%, adjusted odds-ratio (aOR) = 2.9, CI = 2.0-4.3) or non-nosocomial healthcare-related SAB (IE: 12%, aOR = 2.3, CI = 1.4-3.5). S. aureus meningitis (IE: 59%), persistent bacteremia at 48 hours (IE: 25%) and C-reactive protein > 190 mg/L (IE: 15%) were also independently associated with IE. Criteria for severe sepsis or septic shock were met in 30% of SAB without IE (overall in hospital mortality rate 24%) and in 51% of IE (overall in hospital mortality rate 35%).CONCLUSION: SAB is still a severe disease, mostly related to healthcare in a high-income country. IE is the most frequent complication and occurs frequently in patients without known predisposing condition

Prothrombotic Hemostasis Disturbances in Patients with Severe COVID-19:Individual daily data

This data article accompanies the manuscript entitled: "Prothrombotic Disturbances of hemostasis of Patients with Severe COVID-19: a Prospective Longitudinal Observational Cohort Study" submitted to by the same authors. We report temporal changes of plasma levels of an extended set of laboratory parameters during the ICU stay of the 21 COVID-19 patients included in the monocentre cohort: CRP, platelet count, prothrombin time; Clauss fibrinogen and clotting factors II, V and VIII levels, D-dimers, antithrombin activity, protein C, free protein S, total and free tissue factor pathway inhibitor, PAI-1 levels, von Willebrand factor antigen and activity, ADAMTS-13 (plasma levels); and of two integrative tests of coagulation (thrombin generation with ST Genesia) and fibrinolysis (global fibrinolytic capacity - GFC). Regarding hemostasis, we used double-centrifuged frozen citrated plasma prospectively collected after daily performance of usual coagulation tests. Demographic and clinical characteristics of patients and thrombotic and hemorrhagic complications were also collected from patient's electronic medical reports

Staphylococcus aureus infective endocarditis versus bacteremia strains: Subtle genetic differences at stake

AbstractInfective endocarditis (IE)(1) is a severe condition complicating 10–25% of Staphylococcus aureus bacteremia. Although host-related IE risk factors have been identified, the involvement of bacterial features in IE complication is still unclear. We characterized strictly defined IE and bacteremia isolates and searched for discriminant features. S. aureus isolates causing community-acquired, definite native-valve IE (n=72) and bacteremia (n=54) were collected prospectively as part of a French multicenter cohort. Phenotypic traits previously reported or hypothesized to be involved in staphylococcal IE pathogenesis were tested. In parallel, the genotypic profiles of all isolates, obtained by microarray, were analyzed by discriminant analysis of principal components (DAPC)(2). No significant difference was observed between IE and bacteremia strains, regarding either phenotypic or genotypic univariate analyses. However, the multivariate statistical tool DAPC, applied on microarray data, segregated IE and bacteremia isolates: IE isolates were correctly reassigned as such in 80.6% of the cases (C-statistic 0.83, P<0.001). The performance of this model was confirmed with an independent French collection IE and bacteremia isolates (78.8% reassignment, C-statistic 0.65, P<0.01). Finally, a simple linear discriminant function based on a subset of 8 genetic markers retained valuable performance both in study collection (86.1%, P<0.001) and in the independent validation collection (81.8%, P<0.01). We here show that community-acquired IE and bacteremia S. aureus isolates are genetically distinct based on subtle combinations of genetic markers. This finding provides the proof of concept that bacterial characteristics may contribute to the occurrence of IE in patients with S. aureus bacteremia