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Abstract Background Migrants are individuals who move to a different country from their usual place of residence. Japan’s migrant population, particularly technical interns and students, has been growing. Even before the pandemic, previous studies have highlighted difficulties faced by migrants in utilizing healthcare services. This study examined the uptake of COVID-19 vaccination, testing, and medical care among Myanmar migrants in Japan; identified the factors associated with this uptake; and described the difficulties encountered when utilizing these services. Methods A cross-sectional study was conducted between March and April 2023 targeting Myanmar migrants over 18 years residing in Japan for more than 6 months. An online self-administered questionnaire in Myanmar language covered socioeconomic characteristics; history of COVID-19 vaccination, testing, and medical care; and difficulties encountered while utilizing these services with multiple-choice questions. Multivariate logistic regression analysis was performed separately to identify the factors associated with the uptake of COVID-19 vaccination, testing, and medical care. Results Among the 207 participants, 52% (n = 108) were under 30 years, 30% (n = 62) were male, and 31% (n = 65) were low-skilled workers (technical interns and students). Overall, 91% (n = 189) had received the COVID-19 vaccination, 76% (n = 157) had been tested for COVID-19, and 43% (n = 68) tested positive. However, only 77% (n = 52) of COVID-19 patients sought medical care. Participants under 30 years of age were less likely to receive the COVID-19 vaccine compared to those aged 30 and older (adjusted odds ratio [aOR] 0.10, 95% confidence interval [CI] 0.01–0.88, p = 0.038). Low-skilled workers were less likely to seek medical care compared to those holding other categories of residential status (aOR 0.12, 95% CI 0.02–0.79, p = 0.027). Among service users, 5% faced difficulties with COVID-19 vaccination, 10% with testing, and 17% with receiving medical care. Long waiting times and complex reservation processes were the main difficulties encountered. Conclusions The uptake of COVID-19 vaccination, testing, and medical care in this sample was reasonably good. However, individuals under 30 years of age showed lower uptake of vaccination, while low-skilled workers had lower uptake of medical care. Strengthening education and support for young migrants and low-skilled workers regarding COVID-19 and other infectious diseases is essential, especially in workplaces and educational institutions.

Objectives: This study aimed to review the progress and challenges of COVID-19 vaccine roll-out for migrants in Japan and discuss the approaches to address the challenges and better prepare for future waves of COVID-19 and other pandemics. Methods: We conducted a literature review using an assessment framework which we developed building upon existing frameworks and tools on access to health services and COVID-19 vaccination among migrants. Results: COVID-19 vaccination coverage among foreigners might be lower than that of nationals although the data on foreigners were not widely available. A gap appeared to exist between the government's efforts to disseminate vaccine-related information through multi-lingual websites and migrant communities as recipients. A series of barriers for migrants were identified at different stages of the vaccination process. While efforts were made by different units of local governments, NGOs, migrant communities, and international exchange associations, linkages across sectors and scaling-up appeared to be an issue. No foreigners were explicitly excluded from the entitlements of COVID-19 vaccination. The national level guidance, however, allowed sub-national levels to make a decision on whether or not undocumented foreigners should be reported to the immigration office or law enforcement when providing the services. In consequence, units in charge of public health and vaccination of some municipalities did not offer vaccination to those in need. Conclusion: Migrants, especially those unregistered face various barriers in accessing COVID-19 vaccination. It is critical to assess and address challenges concerning channels of information dissemination, pathways to access services, obstacles for vulnerable migrants, and data for evidence-based actions.

Abstract Dam‐mediated biological invasions are a serious problem all over the world. Once established in reservoirs, the invasive species have catastrophic impacts on the river ecosystems downstream, and thus, rapid monitoring of invasive species is an urgent issue for the effective removal of them and the conservation management of native ecosystems. Here, we verified the utility of environmental DNA (eDNA) analysis as a tool to effectively monitor three invasive fish species (bluegill, largemouth bass, and smallmouth bass) in reservoirs using multiplex real‐time PCR. First, to determine the optimal sampling location and season to detect eDNA from these species, we analyzed the eDNA in water samples from shore and offshore sites in three reservoirs all year around. We found that eDNA detection rates either did not differ between sampling locations or were higher for shore than offshore sites. In addition, eDNA detection rates were higher in spring (breeding season of target species) and/or summer than winter. Second, we extensively surveyed the distribution of the three species in 30 reservoirs in Japan using eDNA analysis. Consequently, a single eDNA‐based surveillance in summer allowed to match approximately 90% of the presence/absence of the invasive fish species known from 27 yr of administrative capture‐based surveillances. Given these results, we recommend collecting the replicated water samples from shore sites in summer or the breeding season for the effective detection of invasive fish eDNA in reservoirs. Our eDNA assays with multiplex real‐time PCR enable the rapid and sensitive monitoring of invasive fish distribution in reservoirs.

Creep-fatigue damage preferentially exceeds at stress concentration portions in high temperature components such as steam turbine rotors during cyclic start up- shut down operation. Therefore development of an accurate crack initiation life assessment method under creep-fatigue conditions at the stress concentration portions under multiaxial stress states is necessary to maintain reliable operation. In this study, creep-fatigue tests using circular notch bar specimens on a CrMoV forging steel have been conducted to clarify effect of stress conditions on failure life. Three dimensional finite element elastic-plastic creep analyses have been performed. Fatigue lives of the notch specimens are about 10 times shorter than those of plain specimens, and the lives of the notch specimen under the creep-fatigue condition are about 1/5 times of the plain specimen. From observation of notch root of the creep-damage specimens, it suggested that most of the creep-fatigue life was occupied by crack propagation up to 1mm from the notch surface. It was also indicated that triaxial tension stress state occurs around the notch root surface and stresses decrease with distance from the notch root surface by the inelastic analysis. A new creep-fatigue life evaluation procedure of notch specimens, in which concept of a damage evaluation area was introduced, was proposed by considering damage extension and the stress component distribution around the notch root. As a result, creep-fatigue lives of the notch specimens were accurately predicted by coupling of the new procedure and the nonlinear damage accumulation rule.