When a human body of workforce touches charged objects of live line, an electric current by the electric shock flows in the human body and the electric shock accident occurs. The human body feels a numbness when the electric current of more than 1 mA flows through it, and the workforce is dead by occurrence of ventricular fibrillation when the current of about 50 mA flows through it. When we consider the electric shock accident on the earth, there is a possibility of occurrence of many electrical fatal accidents. We need to provide a basis of the prevention of electric shock accident for utilizing the prevention of the accident of not only Japan, but also U.S.A etc. Though the studies on the prevention of electric shock accident is performed on domestic and overseas, the research study on recent electric shock accident is not so many. This study reports the study results capable of eliminating the electrical fatal accident in future when we consider the causes and preventive measures from case studies of electrical fatal accident by the electric shock in 2018. The fruits will expect to useful for the prevention of electrical fatal accident by the electric shock.

We conducted a questionnaire survey among nurses, medical doctors, radiological technologists, and pharmacists in 2020 to identify the factors explanatory associated with work-related and medical accident risks among medical professionals at university hospitals in Japan. Participants were divided into high- and low-risk groups based on their experiences of work-related and medical accidents from the last year before the survey, and their mental health, job-related stress by effort-reward imbalance, and time factors were compared. Among them, 22% of nurses, 16% of medical doctors, 17% of radiological technologists, and 18% of pharmacists were in the high-risk group. Moreover, the high-risk groups, except for pharmacists, had significantly poor health statuses than the low-risk groups. Nurses and medical doctors in the high-risk group had significantly longer working hours and more night shifts than the low-risk groups. This study highlighted that job stress was significantly and independently associated with a high risk of work-related and medical accidents in all occupations, even when adjusted for confounding factors, health status, and time factors. The study suggested that mitigating and controlling stress would reduce accident risk among medical professionals performing interpersonal work.

The implementation of risk assessment (hereafter, “RA”) at the design stage is essential for preventing workplace accidents related to the use of machines. However, among small and medium-sized machine manufactures and integrators in particular, the dissemination and embeddedness of RA are impeded by the difficulty of “hazard identification”, which is regarded as the most important step in the whole RA process.

In order to establish an effective method to support machine designers who are inexperienced in RA, this study focuses on two aspects of difficulty of hazard identification that can be resolved by utilizing the requirements stated in industrial standards related to machinery safety. This concept is inspired by the application of type-C machine safety standards to obtain a presumption of conformity with the European Machinery Directive. A hazard identification support software tool embodying the concept is proposed and its specifications and functions are described in this paper. As results of confirming operation of the tool by four industrial safety consultants, the proposed support method itself was highly regarded, however, some points to be improved were noted that could increase the effectiveness for the target designers.

This study describes a powered exoskeleton designed to restore the gait of locomotion in individuals with spinal cord injury, and testing of its operation. The device comprises an adjustable frame to support the patient’s weight, four actuators to motorize the hip and knee joints, and a motion sensor for gait trigger to detect pelvic tilt. It is controlled using a programmable logic controller system. Additionally, it includes crutches with a wireless switch. The length and width of the frame can be adjusted. Moreover, the joint angles for abduction and adduction can be adjusted to fit X- and O-legs. The actuator consists of a reduction gear with a ratio of 1:101 and a brushless DC motor, which generates a maximum torque of 90.9 Nm. A preliminary fitting test for healthy subjects showed that the frame could be adjusted to fit the shape of the human lower limbs, confirming the effectiveness of the adjustment functionalities. The operation test demonstrated that the target motions could be performed normally under unloaded conditions, and then confirmed that a standard-sized healthy male wearing the prototype could safely perform the standing-up, walking, and sitting-down actions. In addition, crutches with wireless switches enabled remote operation, improving usability.

Despite the promotion of measures to prevent occupational accidents based on risk assessment (hereinafter, ‘RA’) for machinery, implementation at small and medium-sized business remains insufficient. With the aim of supporting small businesses in performing RA, this study focused on hazard identification, which is considered the most important step in the RA process. To make it easier to consider the causal factors in possible occupational accidents related to machinery, the hazard list that has commonly been used as the starting point for hazard identification was reformulated with illustrations created based on our analysis of reported machinery accident cases. Specifically, the processes whereby each hazard led to an accident during the use of machinery in each reported case were presented as visualised information for the person(s) involved in hazard identification. A procedure was proposed for the simplified identification of hazards, using the illustrated hazard list, and a tablet PC app was developed based on this procedure. The results of an effectiveness evaluation conducted with the participation of three business sites indicate that the proposed hazard identification method was viewed favourably, although some points remain to be improved.

Long working hours are associated with increases in cardiovascular diseases and are also important factors for karoshi. We have confirmed that cardiovascular burden increases due to long working hours in laboratory, and older workers (over 50s) suffer more cardiovascular burden than younger workers. Aging is not only a risk factor for cardiovascular diseases, but it can also be a factor that affects work efficiency. This paper reports the results of subjective burden and task performance of workers in their 30s to 60s. We examined the subjective fatigue, stress and sleepiness and task performance during long working hours in lab. The experiment conducted from 9:00 to 22:00 and was divided into four task sessions. In each session, three tasks (color-word task, mental arithmetic task and number copy task) were performed once for 45-minutes in random order. As results, subjective stress and fatigue increased and task performance was significantly higher in the late afternoon and evening. No differences among age groups were detected. In conclusion, although task performance has not declined, attention is required if long working hours are unavoidable due to increased mental and physical burden.

This study examined the characteristics and workloads of overwork-related disorders’ cases among teachers in public elementary and junior high school. We examined 88 cases, including 52 cases of cerebrovascular/cardiovascular diseases (CCVD) and 36 cases of mental disorders, who were compensated between January 2010 and March 2019. The results showed that men accounted for approximately 80% of the cases of CCVD per million people, intracerebral hemorrhage was the most common diagnosis. For mental disorders, the number of cases per million people by gender was higher for men than for women. The depressive episode was the most common diagnosis. The advisor of club activities was the most common workload in the cases of CCVD, affecting the cases of “long working hours.” And the most common workload in mental disorders was public interpersonal conflicts. “The advisor of club activities” and “interpersonal relationships with parents” contributed to the incidence of CCVD and mental disorders. We propose that the above factors should be solved as measures to prevent overwork-related disorders among public elementary and secondary school teachers.

Airborne disease transmission can infect large numbers of individuals simultaneously; therefore, prevention is important, particularly in high-risk medical and elderly care facilities. However, currently, no checklists are available to detect and improve infection control issues at these facilities. In this study, we developed a checklist containing eight control items for each of the three protective measures against aerosol infection (ventilation, air purification, and airflow control) and specific control goals. Based on this checklist, 18 medical and elderly care facilities (a total of 263 rooms) were surveyed in this study. Our findings showed that 72% of rooms in which we detected infection control issues had inadequate mechanical ventilation, 48% of which were secondary to inadequate cleaning. As a background factor, outdoor ventilation louvers in particular were not designed to facilitate inspection and could not be cleaned; therefore, long-term dust accumulation led to blockages. Additionally, 21% of issues associated with mechanical ventilation were associated with forgetfulness regarding turning on switches and background factors such as inadequate operation of switches, difficulties with the user interface of the operation panel, and handover errors in centralized control. Furthermore, 18% of the rooms in which we detected infection control issues had snags with airflow control owing to differential pressure gradients. Although we detected flaws in <5% of rooms, faults in the installation method of blowers, inhibition of natural ventilation, and carbon dioxide concentration >1000 ppm were also observed in this study. These findings highlight the usefulness of our proposed checklist for detection of the aforementioned concerns.

This study investigates the prevalence and underlying factors of alienation and discrimination experienced by employees in the workplace, with a particular focus on hindrances to collaboration among diverse human resources. A self-administered, unsolicited questionnaire survey was conducted in 2022 among faculty members of an educational and research institution. Statistical and qualitative research methods were used to analyze the responses, for open-ended descriptions of their experiences. The results showed that “job position/occupation” was the most frequently cited factor contributing to feelings of alienation and discrimination (21 respondents), followed by “gender” (8), and“physical and mental disabilities” (6). “Using the Mann-Whitney U-test to examine the relationship between respondents' basic attributes and the number of factors in which they reported experiencing alienation and discrimination, it was found that significantly more respondents who had relatives needing care and teachers reported feeling marginalized and discriminated against.” Through analysis of open-ended descriptions, three key elements were identified as constituting the experience of feeling marginalized and discriminated: “Exclusion due to stereotypes and assumptions,” “Reservation to surrounding staff,” and “Hierarchical relationship in the work environment.”

Since January 2020, the cases of infection with the novel coronavirus in Japan have increased drastically. It became an emerging infectious disease resulting in high infections and deaths. To date, the main infection control measures were avoidance of sealing, social distancing, ventilation, and disinfection. Since the early stages of the epidemic, partitions were installed in restaurants and other places as physical barriers to prevent direct droplet infection. In this study, the capability of different partition shapes to effectively block the virus-containing droplets was studied.

Subsequently, we designed and sprayed a smoke produced by the generator mimicking the virus-containing droplets sneezed by humans and evaluated the effectiveness of the different partition shapes in preventing droplet infection. The smoke failed to migrate to the opposite side of the partition for all the shapes.

Particularly, partitions with wall panels on both sides completely blocked the smoke diffusion to either side of the partition. Thus, this partition type most effectively prevented the spread of the smoke.

This study aimed to examine the joint association of daily rest period (DRP) and sleep duration with occupational stress and sickness absence in Japanese daytime employees. This study utilized a web-based cross-sectional survey conducted in February 2022. The 13,306 participants reported their DRPs and sleep duration. Occupational stress was assessed using the New Brief Job Stress Questionnaire, while the frequency of sickness absence was measured using a 4-point Likert scale. The participants were categorized into 14 groups based on their DRPs and sleep duration. Logistic regression analyses revealed that the combination of a short DRP and normal sleep duration, as well as the combination of an adequate DRP and short sleep duration, were significantly associated with high occupational stress compared to the reference group (adequate DRP and normal sleep duration). These results indicate that not only normal sleep duration but also sufficient DRPs are important for reducing occupational stress. However, only the combination of a short DRP and normal sleep duration, and not the combination of an adequate DRP and short sleep duration, were significantly associated with a lower frequency of sickness absence. This may be owing to the possibility that employees with a short DRP (indicating longer working hours) are too busy to take leave even when they are sick.