Oxidation-induced degradation and performance fluctuation of solid oxide fuel cell Ni anodes under simulated high fuel utilization conditions

High fuel utilization (Uf) conditions in a small-scale electrolyte-supported solid oxide fuel cell (SOFC) with an Ni-ScSZ anode were approximated by adjusting the gas composition to correspond to that in the downstream region of an SOFC stack. At Uf = 80%, and with a cell voltage of 0.5 V, the ohmic resistance fluctuated slightly from the early stages of operation, and became much more significant after 80 h. High current density and large polarization were found to promote Ni agglomeration, leading to insufficient connectivity of the Ni nanoparticles. At Uf = 95%, and with a cell voltage of 0.6 V, fluctuations in the polarization were observed at a much earlier stage, which are attributed to the highly humidified fuel. In particular, significant degradation was observed when the compensated anode potential (which incorporates the anode ohmic losses) approached the Ni oxidation potential. Ohmic losses in the anode are considered to influence Ni oxidation by exposing Ni near the electrolyte to a more oxidizing atmosphere with the increase in oxygen ion transport. Stable operation is therefore possible under conditions in which the compensated anode potential does not approach the Ni oxidation potential, assuming a stable interconnected Ni network

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

Novel mutation in the ALPL gene with a dominant negative effect in a Japanese family

Introduction Hypophosphatasia (HPP) is caused by mutations in the ALPL gene encoding tissue nonspecific alkaline phosphatase (TNSALP) and inherited in either an autosomal recessive or autosomal dominant manner. It is characterized clinically by defective mineralization of bone, dental problems, and low serum ALP levels. In the current report, we demonstrate a novel mutation in the ALPL gene (c.244G > A p.Gly82Arg) in a Japanese family with low serum ALP levels. Materials and methods The ALPL gene analysis using hybridization capture-based next-generation sequencing was performed. The expression plasmids of the wild type and mutated TNSALP were introduced into COS-7 cells. The enzymatic activity of ALP in the cell lysates was measured using p-nitrophenylphosphate as a substrate. Results TNSALP with the novel ALPL mutation (c.244G > A p.Gly82Arg) completely lost its enzymatic activity and suppressed that of wild-type TNSALP, corroborating its dominant negative effect. The diagnosis of autosomal dominant HPP was confirmed in three members of the family. Conclusion Our approach would help to avoid the inappropriate use of bone resorption inhibitors for currently mis- or under-diagnosed HPP, given that the presence of further, yet undetected mutations of the ALPL gene are plausible

Single-Molecule Fluorescence Detection of Effective Adsorption Sites at the Metal Oxide–Solution Interface

Nanoscale mapping of adsorption sites for molecules or ions at solid–liquid interfaces has not been explored in detail because of the difficulty in probing both stochastic adsorption/desorption events and heterogeneous surface structures. We report here the application of single-molecule-based super-resolution fluorescence microscopy using a catechol-modified boron–dipyrromethene dye (CA-BODIPY), which serves as a fluorescent reporter, to identify the locations of effective adsorption sites on metal oxide surfaces. Upon adsorption on a TiO₂ nanoparticle, individual CA-BODIPY molecules exhibited detectable fluorescence because of the formation of chelating complexes between the catechol moiety and the surface Ti sites. Interestingly, a significant effect of the crystal face on the adsorption preference for CA-BODIPY was found in the case of anatase TiO₂ microcrystals in neutral water: {101} > {001} ≈ {100}. In an aprotic solvent such as acetonitrile, however, the opposite crystal face effect was observed; this implies a significant contribution of solvent molecules to the adsorption of organic compounds on specific surfaces. From the quantitative analysis of the formation rate of fluorescent complexes per unit area, it was found that nanometer-sized TiO₂ crystals have superior adsorptivity over micrometer-sized TiO₂ crystals and an atomically flat TiO₂ surface. This observation is consistent with the higher density of surface defects on the nanoparticles. Furthermore, it was revealed that CA-BODIPY molecules are preferentially adsorbed on the top branches of α-Fe₂O₃ micropines, where a high density of exposed Fe cations is expected. Our methodology and findings yield new insights into the mechanisms underlying the synthesis and (photo)­catalytic activity of metal oxide particles with different sizes and shapes

Modeling the functions of condensin in chromosome shaping and segregation - Fig 3

<p>(<i>A</i>) Time-course evolution of the asphericity, overlap, and trans-attraction. Configurations of the two chromosomes and distribution of condensins at <i>t</i> = 0.0 (<i>B</i>), 0.2 (<i>C</i>), and 1.0 (<i>D</i>). The blue and green lines represent two different chromosomes. The red and purple points are condensins bound to the blue and green chromosomes, respectively. The corresponding dynamics are shown in <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1006152#pcbi.1006152.s005" target="_blank">S1 Movie</a>. Each chromosome has 5000 monomers and 100 loops. (<i>F</i>_cond, Δ, <i>F</i>_loop) = (1.0, 1.0, 1.0).</p

Modeling the functions of condensin in chromosome shaping and segregation

<div><p>The mechanistic details underlying the assembly of rod-shaped chromosomes during mitosis and how they segregate from each other to act as individually mobile units remain largely unknown. Here, we construct a coarse-grained physical model of chromosomal DNA and condensins, a class of large protein complexes that plays key roles in these processes. We assume that condensins have two molecular activities: consecutive loop formation in DNA and inter-condensin attractions. Our simulation demonstrates that both of these activities and their balancing acts are essential for the efficient shaping and segregation of mitotic chromosomes. Our results also demonstrate that the shaping and segregation processes are strongly correlated, implying their mechanistic coupling during mitotic chromosome assembly. Our results highlight the functional importance of inter-condensin attractions in chromosome shaping and segregation.</p></div