Microstructure and mechanical properties of high strength steel deposits obtained by Wire-Arc Additive Manufacturing

Wire-arc additive manufacturing has become an alternative way to produce industrial parts. In this work 15 kg walls are built with an effective building rate of 4.85 kg/h using an ER100 wire providing good tensile properties and toughness under welding conditions. The thermal evolution of the walls during manufacturing is measured by thermocouples and an IR camera: it depends on process parameters, deposit strategy and the size of the part. The walls are then characterised as deposit and after heat treatment through hardness, tensile and Charpy-V notch tests. The results show a fine microstructure with unexpected retained austenite and coarse allotriomorphic ferrite in the as deposited walls. The final hardness values vary from about 220 to 280 HV2; the yield stress and tensile strength are 520 and 790 MPa, respectively, and a toughness of about 50 J is obtained at room temperature. The heat treatment transforms the retained austenite, leading to an improvement of the yield stress to 600 MPa

Etude numérique du procédé de soudage par friction malaxage

Le procédé de soudage par friction malaxage (F.S.W.) est particulièrement bien adapté pour l'assemblage d'alliages d'aluminium. La présente étude porte sur la modélisation thermo-mécanique de ce procédé et sur son implantation dans le code d'éléments finis ABAQUS/Explicit. Un état de l'art est présenté, décrivant diverses écoles traitant de l'effet thermique et mettant en évidence différentes approches basées sur une formulation lagrangienne, eulérienne ou mixte (A.L.E.). Une première modélisation du procédé pour un outil avec pion lisse est ainsi proposée. Les résultats numériques concernent aussi bien le champ de températures que les champs mécaniques au sein de la tôle à souder durant les phases transitoire et stationnaire du procédé. Cette étude a pour but de fournir à long terme un outil prédictif permettant de déterminer les paramètres de soudage à utiliser lors de la mise en œuvre du procédé

Tolerance of Prolonged Oral Tedizolid for Prosthetic Joint Infections: Results of a Multicentre Prospective Study

Objectives: Data on clinical and biological tolerance of tedizolid (TZD) prolonged therapy are lacking. Methods: We conducted a prospective multicentre study including patients with prosthetic joint infections (PJIs) who were treated for at least 6 weeks but not more than 12 weeks. Results: Thirty-three adult patients of mean age 73.3 ± 10.5 years, with PJI including hip (n = 19), knee (n = 13) and shoulder (n = 1) were included. All patients were operated, with retention of the infected implants and one/two stage-replacements in 11 (33.3%) and 17/5 (51.5%/15.2%), respectively. Staphylococci and enterococci were the most prevalent bacteria identified. The mean duration of TZD therapy was 8.0 ± 3.27 weeks (6–12). TZD was associated with another antibiotic in 18 patients (54.5%), including rifampicin in 16 cases (48.5). Six patients (18.2%) had to stop TZD therapy prematurely because of intolerance which was potentially attributable to TZD (n = 2), early failure of PJI treatment (n = 2) or severe anaemia due to bleeding (n = 2). Regarding compliance with TZD therapy, no cases of two or more omissions of medication intake were recorded during the whole TZD treatment duration. Conclusions: These results suggest good compliance and a favourable safety profile of TZD, providing evidence of the potential benefit of the use of this agent for the antibiotic treatment of PJIs

Increased risk of severe COVID-19 in hospitalized patients with SARS-CoV-2 Alpha variant infection: a multicentre matched cohort study

International audienceBackground: The impact of the variant of concern (VOC) Alpha on the severity of COVID-19 has been debated. We report our analysis in France.Methods: We conducted an exposed/unexposed cohort study with retrospective data collection, comparing patients infected by VOC Alpha to contemporaneous patients infected by historical lineages. Participants were matched on age (± 2.5 years), sex and region of hospitalization. The primary endpoint was the proportion of hospitalized participants with severe COVID-19, defined as a WHO-scale > 5 or by the need of a non-rebreather mask, occurring up to day 29 after admission. We used a logistic regression model stratified on each matched pair and accounting for factors known to be associated with the severity of the disease.Results: We included 650 pairs of patients hospitalized between Jan 1, 2021, and Feb 28, 2021, in 47 hospitals. Median age was 70 years and 61.3% of participants were male. The proportion of participants with comorbidities was high in both groups (85.0% vs 90%, p = 0.004). Infection by VOC Alpha was associated with a higher odds of severe COVID-19 (41.7% vs 38.5%-aOR = 1.33 95% CI [1.03-1.72]).Conclusion: Infection by the VOC Alpha was associated with a higher odds of severe COVID-19

A highly virulent variant of HIV-1 circulating in the Netherlands

We discovered a highly virulent variant of subtype-B HIV-1 in the Netherlands. One hundred nine individuals with this variant had a 0.54 to 0.74 log10 increase (i.e., a ~3.5-fold to 5.5-fold increase) in viral load compared with, and exhibited CD4 cell decline twice as fast as, 6604 individuals with other subtype-B strains. Without treatment, advanced HIV-CD4 cell counts below 350 cells per cubic millimeter, with long-term clinical consequences-is expected to be reached, on average, 9 months after diagnosis for individuals in their thirties with this variant. Age, sex, suspected mode of transmission, and place of birth for the aforementioned 109 individuals were typical for HIV-positive people in the Netherlands, which suggests that the increased virulence is attributable to the viral strain. Genetic sequence analysis suggests that this variant arose in the 1990s from de novo mutation, not recombination, with increased transmissibility and an unfamiliar molecular mechanism of virulence