Corrosion and Erosion of Ferritic Steel by Liquid Bismuth

Static corrosion of Fe-C-Cr alloys and erosion of Fe-C and Fe-Cr alloys due to the contact with liquid bismuth were studied. For the static corrosion test, magnesium as a deoxidant and zirconium as an inhibitant were added into liquid bismuth prior to the immersion of specimens. The erosion test was carried out by applying an ultrasonic oscillation of 20±2 kc in frequency and 15 microns in amplitude. The results obtained were as follows. (1) In Fe-C alloys, when the carbon content increases the degree of static, corrosion becomes less. In Fe-C-Cr alloys, the chromium content enhances the degree of static corrosion. For the inhibition of corrosion the increase of carbon content in the alloy may be necessary. (2) From the erosion test it was found that the surface pits are not due to a chemical corrosion but to a mechanical attack, and that the degree of erosion chiefly depends on the hardness of the alloy

DOCK2 is involved in the host genetics and biology of severe COVID-19

「コロナ制圧タスクフォース」COVID-19疾患感受性遺伝子DOCK2の重症化機序を解明 --アジア最大のバイオレポジトリーでCOVID-19の治療標的を発見--. 京都大学プレスリリース. 2022-08-10.Identifying the host genetic factors underlying severe COVID-19 is an emerging challenge. Here we conducted a genome-wide association study (GWAS) involving 2, 393 cases of COVID-19 in a cohort of Japanese individuals collected during the initial waves of the pandemic, with 3, 289 unaffected controls. We identified a variant on chromosome 5 at 5q35 (rs60200309-A), close to the dedicator of cytokinesis 2 gene (DOCK2), which was associated with severe COVID-19 in patients less than 65 years of age. This risk allele was prevalent in East Asian individuals but rare in Europeans, highlighting the value of genome-wide association studies in non-European populations. RNA-sequencing analysis of 473 bulk peripheral blood samples identified decreased expression of DOCK2 associated with the risk allele in these younger patients. DOCK2 expression was suppressed in patients with severe cases of COVID-19. Single-cell RNA-sequencing analysis (n = 61 individuals) identified cell-type-specific downregulation of DOCK2 and a COVID-19-specific decreasing effect of the risk allele on DOCK2 expression in non-classical monocytes. Immunohistochemistry of lung specimens from patients with severe COVID-19 pneumonia showed suppressed DOCK2 expression. Moreover, inhibition of DOCK2 function with CPYPP increased the severity of pneumonia in a Syrian hamster model of SARS-CoV-2 infection, characterized by weight loss, lung oedema, enhanced viral loads, impaired macrophage recruitment and dysregulated type I interferon responses. We conclude that DOCK2 has an important role in the host immune response to SARS-CoV-2 infection and the development of severe COVID-19, and could be further explored as a potential biomarker and/or therapeutic target