Characterization of the effect of ion irradiation on industrially produced GdBa₂Cu₃O₇−δ superconducting tapes using a slow positron beam

To investigate the effect of irradiation-induced defects on the superconducting characteristics of industrially produced superconductor—GdBa₂Cu₃O₇−δ (GdBCO)—coated conductors (CCs), we irradiated the GdBCO CCs with Au ions at 2 or 10 MeV and probed them using a slow positron beam. Vacancy clusters were detected in both unirradiated and irradiated GdBCO CCs. However, the effect of ion irradiation on the GdBCO CCs was characterized as a slight reduction in the positron annihilation rate with low-momentum electrons. We also found a correlation between the annihilation rate of low-momentum electrons and the superconducting transition temperature

HLA-DRB1 and DQB1 alleles in Japanese type 1 autoimmune hepatitis: The predisposing role of the DR4/DR8 heterozygous genotype

ObjectiveAutoimmune hepatitis (AIH) is a chronic progressive liver disease. AIH is composed predominantly of type 1 in Japanese populations. The genetic and environmental factors are associated with the pathogenesis of AIH. HLA-DRB1*03:01 and *04:01 are associated with type 1 AIH in European and *04:05 in Japanese populations. Here, we conducted an HLA association study in order to find HLA alleles or haplotypes predisposing or protective for Japanese AIH.MethodsHLA-DRB1 and DQB1 genotyping of 360 type 1 AIH patients and 1026 healthy controls was performed.ResultsThe predisposing association of DRB1*04:01 (P = 0.0006, corrected P [Pc] = 0.0193, odds ratio [OR] 2.97, 95% confidence interval [CI] 1.62–5.43), DRB1*04:05 (P = 1.89×10−21, Pc = 5.86×10−20, OR 3.41, 95% CI 2.65–4.38), and DQB1*04:01 (P = 4.66×10−18, Pc = 6.99×10−17, OR 3.89, 95% CI 2.84–5.33) and the protective association of DRB1*13:02 (P = 0.0003, Pc = 0.0080, OR 0.48, 95% CI 0.32–0.72) with Japanese type 1 AIH were observed. An association of the DR4/DR8 heterozygous genotype with Japanese AIH was identified for the first time (P = 3.12×10−9, OR 3.52, 95% CI 2.34–5.29). Susceptible diplotypes were DRB1*04:05-DQB1*04:01/DRB1*08:02-DQB1*03:02 (P = 0.0004, OR 24.77, 95% CI 1.45–424.31) and DRB1*04:05-DQB1*04:01/DRB1*08:03-DQB1*06:01 (P = 1.18×10−6, OR 10.64, 95% CI 3.19–35.46). Serum levels of Immunoglobulin G and Immunoglobulin M, International Autoimmune Hepatitis Group score, positive rate of anti-smooth muscle antibodies, and the rate of definite AIH were higher in AIH patients with DRB1*04:05 than without.ConclusionsThe important roles of specific combinations of DRB1 and DQB1 alleles or haplotypes in the pathogenesis of type 1 AIH were suggested. The association of DR4/DR8 heterozygous genotype suggested the pathologic importance of trans-complementing DQα-β heterodimer molecules encoded by DQA1 allele of one haplotype and the DQB1 allele of the other haplotype, as it was proposed in the HLA association studies of Type 1 diabetes

NMR study for electrochemically inserted Na in hard carbon electrode of sodium ion battery

The state of sodium inserted in the hard carbon electrode of a sodium ion battery having practical cyclability was investigated using solid state 23Na NMR. The spectra of carbon samples charged (reduced) above 50 mAh g−1 showed clear three components. Two peaks at 9.9 ppm and 5.2 ppm were ascribed to reversible sodium stored between disordered graphene sheets in hard carbon because the shift of the peaks was invariable with changing strength of external magnetic field. One broad signal at about −9 to −16 ppm was assigned to sodium in heterogeneously distributed closed nanopores in hard carbon. Low temperature 23Na static and magic angle spinning NMR spectra didn't split or shift whereas the spectral pattern of 7Li NMR for lithium-inserted hard carbon changes depending on the temperature. This strongly suggests that the exchange of sodium atoms between different sites in hard carbon is slow. These studies show that sodium doesn't form quasi-metallic clusters in closed nanopores of hard carbon although sodium assembles at nanopores while the cell is electrochemically charged

Changes of behavior and consciousness in COVID-19

新型コロナウイルスの感染症の拡大と長期化に伴い，世の中はパンデミック状態にある一方でテレワークの普及によって，個人生活にとってはメリットもあると考えられる．そこで現在の行動やコミュニケーション等の意識の変化，さらにフレイルなど健康面の課題について①生活，行動と意識に関するアンケート，②通勤，勤務と行動と意識に関するアンケート2種類のWeb調査により実態を明らかにした．その結果，未知のウイルスに対する脅威感から，人々の意識やライフスタイルも大きく変容していて，在宅時間の増加によりメリットもある一方で，時間の使い方は自己への投資などには回っておらず，健康面では不安を抱えていることが明らかになり，フレイル等により健康寿命の短縮が危惧されるなど，新たな日常スタイルに向けての課題があることが明らかになった．With the spread and prolongation of the new coronavirus infection, the world is in a pandemic state, but the spread of telework is thought to have benefits for personal life. Therefore, awareness of current behavior and communication, etc. Regarding changes and health issues such as frailty, (1) questionnaires on life, behavior and consciousness, and (2) questionnaires on commuting work and behavior and consciousness, the actual situation was clarified by two types of Web surveys. As a result, people's consciousness and lifestyle have changed significantly due to the threat of unknown viruses, and while there are benefits to increasing the time spent at home, spending time is not used for self-investment. However, it became clear that he was worried about his health, and that there were issues for a new daily style, such as fear of shortening healthy life expectancy due to frailty syndrome

Risk Factors for Bleeding After Endoscopic Submucosal Dissection for Gastric Cancer in Elderly Patients Older Than 80 Years in Japan.

Introduction:As the aging of people in a society advances, the number of elderly patients older than 80 years in Japan with gastric cancer continues to increase. Although delayed ulcer bleeding is a major adverse event after endoscopic submucosal dissection (ESD), little is known about characteristic risk factors for bleeding in elderly patients undergoing ESD. This study aimed to evaluate risk factors for delayed bleeding after ESD for gastric cancer in elderly patients older than 80 years.Methods:We retrospectively evaluated the incidence of delayed bleeding after ESD in 10,320 patients with early-stage gastric cancer resected by ESD between November 2013 and January 2016 at 33 Japanese institutions and investigated risk factors for delayed bleeding in elderly patients older than 80 years.Results:The incidence of delayed bleeding in elderly patients older than 80 years was 5.7% (95% confidence interval [CI]: 4.6%-6.9%, 95/1,675), which was significantly higher than that in nonelderly (older than 20 years and younger than 80 years) patients (4.5%, 4.1%-5.0%, 393/8,645). Predictive factors for ESD-associated bleeding differed between nonelderly and elderly patients. On multivariate analysis of predictive factors at the time of treatment, risk factors in elderly patients were hemodialysis (odds ratio: 4.591, 95% CI: 2.056-10.248, P < 0.001) and warfarin use (odds ratio: 4.783, 95% CI: 1.689-13.540, P = 0.003).Discussion:This multicenter study found that the incidence of delayed bleeding after ESD in Japanese patients older than 80 years was high, especially in patients receiving hemodialysis and taking warfarin. Management of ESD to prevent delayed bleeding requires particular care in patients older than 80 years

Effect of neutron–photon converter materials (Cd, Gd, and Sm) on the positron production in a reactor-based slow positron beamline

The change in the amount of positron production when Cd cap, installed as a neutron–photon converter, is replaced with Gd or Sm caps was simulated by Monte Carlo calculations in the slow positron beamline at the Kyoto University Research Reactor, especially focusing on the change in the amount of positron production induced by neutrons emitted from a reactor core. Based on the simulation results, the amount of positron production induced by neutrons obtained using Gd and Sm caps was estimated to decrease to (69±4) % and (54±3)%, respectively, compared with the amount obtained using Cd cap. Meanwhile, Cd and Gd caps with a thickness of 1 mm were evaluated to have almost the same burn-up lifetime. Therefore, a Cd cap is the best choice, while a Gd cap, which has a higher melting point, could be an alternative if the structure of the positron source makes effective cooling difficult

Inverse change in positron lifetimes of vacancies in tungsten by binding of interstitial impurity atoms to a vacancy: A first-principles study

First-principles calculations related to defect complexes formed from a monovacancy and multiple interstitial impurity atoms (hydrogen, carbon, nitrogen, and oxygen atoms) in tungsten were performed. The most stable atomic configurations, the electron density distributions, the binding energies of impurity atoms, and the positron lifetimes of each defect complex were calculated. In calculating positron lifetimes, slight deviations in the initial positions of the H atoms were found to be enhanced by positron localization, which affected the positron lifetimes of the vacancy-hydrogen complexes. In addition, the positron lifetimes of vacancy-nitrogen and vacancy-oxygen complexes were found to become longer in some cases with increasing numbers of impurity atoms that bound to the vacancy. Such longer positron lifetimes with increasing numbers of binding impurity atoms were attributed to the fact that the impurity atoms bind slightly further away from the vacancy, expanding the tungsten lattice

An amorphous phase formation at palladium / silicon oxide (Pd/SiOx) interface through electron irradiation - electronic excitation process

A Pd-Si amorphous phase was formed at a palladium/silicon oxide (Pd/SiOx) interface at room temperature by electron irradiation at acceleration voltages ranging between 25 kV and 200 kV. Solid-state amorphization was stimulated without the electron knock-on effects. The total dose required for the solid-state amorphization decreases with decreasing acceleration voltage. This is the first report on electron irradiation induced metallic amorphous formation caused by the electronic excitation at metal/silicon oxide interface

Characterization of the effect of ion irradiation on industrially produced GdBa₂Cu₃O₇−δ superconducting tapes using a slow positron beam

To investigate the effect of irradiation-induced defects on the superconducting characteristics of industrially produced superconductor—GdBa₂Cu₃O₇−δ (GdBCO)—coated conductors (CCs), we irradiated the GdBCO CCs with Au ions at 2 or 10 MeV and probed them using a slow positron beam. Vacancy clusters were detected in both unirradiated and irradiated GdBCO CCs. However, the effect of ion irradiation on the GdBCO CCs was characterized as a slight reduction in the positron annihilation rate with low-momentum electrons. We also found a correlation between the annihilation rate of low-momentum electrons and the superconducting transition temperature