Thermo-Mechanical Treatment Effects on Stress Relaxation and Hydrogen Embrittlement of Cold-Drawn Eutectoid Steels

The effects of the temperature and stretching levels used in the stress-relieving treatment of cold-drawn eutectoid steel wires are evaluated with the aim of improving the stress relaxation behavior and the resistance to hydrogen embrittlement. Five industrial treatments are studied, combining three temperatures (330, 400, and 460 °C) and three stretching levels (38, 50 and 64% of the rupture load). The change of the residual stress produced by the treatments is taken into consideration to account for the results. Surface residual stresses allow us to explain the time to failure in standard hydrogen embrittlement test

Newly diagnosed rheumatic heart disease among indigenous populations in the Pacific

Objectives Rheumatic heart disease (RHD) remains the leading acquired heart disease in the young worldwide. We aimed at assessing outcomes and influencing factors in the contemporary era. Methods Hospital-based cohort in a high-income island nation where RHD remains endemic and the population is captive. All patients admitted with newly diagnosed RHD according to World Heart Federation echocardiographic criteria were enrolled (2005–2013). The incidence of major cardiovascular events (MACEs) including heart failure, peripheral embolism, stroke, heart valve intervention and cardiovascular death was calculated, and their determinants identified. Results Of the 396 patients, 43.9% were male with median age 18 years (IQR 10–40)). 127 (32.1%) patients presented with mild, 131 (33.1%) with moderate and 138 (34.8%) with severe heart valve disease. 205 (51.8%) had features of acute rheumatic fever. 106 (26.8%) presented with at least one MACE. Among the remaining 290 patients, after a median follow-up period of 4.08 (95% CI 1.84 to 6.84) years, 7 patients (2.4%) died and 62 (21.4%) had a first MACE. The annual incidence of first MACE and of heart failure were 59.05‰ (95% CI 44.35 to 73.75) and 29.06‰ (95% CI 19.29 to 38.82), respectively. The severity of RHD at diagnosis (moderate vs mild HR 3.39 (0.95 to 12.12); severe vs mild RHD HR 10.81 (3.11 to 37.62), p<0.001) and ongoing secondary prophylaxis at follow-up (HR 0.27 (0.12 to 0.63), p=0.01) were the two most influential factors associated with MACE. Conclusions Newly diagnosed RHD is associated with poor outcomes, mainly in patients with moderate or severe valve disease and no secondary prophylaxis

``Mycobacterium massilipolynesiensis'' sp nov., a rapidly-growing mycobacterium of medical interest related to Mycobacterium phlei

International audienceIn French Polynesia, respiratory tract clinical isolate M26, displayed unusual phenotype and contradictory phylogenetic affiliations, suggesting a hitherto unidentified rapidly-growing Mycobacterium species. The phenotype of strain M26 was further characterized and its genome sequenced. Strain M26 genome consists in a 5,732,017-bp circular chromosome with a G + C% of 67.54%, comprising 5,500 protein-coding genes and 52 RNA genes (including two copies of the 16 S rRNA gene). One region coding for a putative prophage was also predicted. An intriguing characteristic of strain M26's genome is the large number of genes encoding polyketide synthases and nonribosomal peptide synthases. Phylogenomic analysis showed that strain M26's genome is closest to the Mycobacterium phlei genome with a 76.6% average nucleotide identity. Comparative genomics of 33 Mycobacterium genomes yielded 361 genes unique to M26 strain which functional annotation revealed 84.21% of unknown function and 3.88% encoding lipid transport and metabolism; while 48.87% of genes absent in M26 strain have unknown function, 9.5% are implicated in transcription and 19% are implicated in transport and metabolism. Strain M26's unique phenotypic and genomic characteristics indicate it is representative of a new species named ``Mycobacterium massilipolynesiensis''. Looking for mycobacteria in remote areas allows for the discovery of new Mycobacterium species

Cold drawn steel wires—processing, residual stresses and ductility — Part II: Synchrotron and neutron diffraction.

International audienceCold drawing of steel wires leads to an increase of their mechanical strength and to a drop in their ductility. The increase of their mechanical strength has long been related to the reduction of the various material scales by an intense plastic deformation. Besides, it was discussed in the companion paper that large plastic deformation leads to the loss of the material hardening capabilities and that, in such a case, residual stresses preserve the elongation to failure of wires. Experimental measurements of residual stresses inside the wire have therefore been undertaken. In this paper, lattice parameters as measured using synchrotron diffraction are compared with those calculated using the residual stress fields as determined by the finite-element method. There is a major disagreement between experimental and numerical results that is too large to be attributed to the errors of the finite-element analyses. Therefore, neutron diffraction experiments have also been performed. These measurements show that there is a significant variation of the lattice parameter with the drawing level, which is not inherited from residual stresses, and that variation is very sensitive to the cooling rate after processing. It is therefore proposed that cold drawing would induce a phase transformation of the steel, possibly a martensitic transformation