In Fe-doped Bi2Te3, we have observed higher mobility, larger linear magnetoresistance, and anomalous quantum oscillations. The angle dependence of Shubnikov-de Haas (SdH) oscillations gives two different periodicities depending on the angle from the c-axis. The low-angle SdH period is identified with a surface origin, while the high-angle period is against the surface origin. The high-angle SdH period well agrees with the de Haas-van Alphen (dHvA) period with a bulk origin. The physical parameters obtained from the quantum oscillations support the crossover between two-dimensional surface state and three-dimensional bulk phase by Fe doping in Bi2Te3.

Objectives: This study compared differences in age-standardized suicide mortality rates, personal characteristics (demographics, employment conditions, and details of suicide), and work-related stress by gender and occupation among workers who had committed suicide in Korea. Methods: Data comprised 413 suicide death claims lodged with the Industrial Accident Compensation Insurance (IACI) from 2010 to 2018, which were coded.We calculated age-standardized suicide mortality rates by gender and occupation.The chi-square test, Fisher's exact test, and t-test were conducted to examine gender differences. Frequency and percentage distribution by gender and occupation were calculated using descriptive statistics. Results: Regardless of gender, age-standardized suicide mortality rate was highest among "Managers." Women who died by suicide were significantly younger and more likely to be unmarried, live alone, and have fewer years of continuous employment than men. "Managers," "Professionals and Related Workers," and "Clerks" experienced similar work-related stresses, including "Difficult work to achieve," "Fail to achieve allocation workload," and "Change of job contents or workload." "Skilled Agricultural, Forestry and Fishery Workers," "Craft and Related Trades Workers," and "Equipment, Machine Operating and Assembling Workers" had higher workrelated stress related to "Severe disease/injury" or "Causing a serious accident" compared with other workers. Conclusions: Work-related stress related to suicide deaths differed by gender and occupation. The gender gap of labor market participation in Korea may affect gender differences in terms of demographics and employment conditions among workers who died by suicide. Our study suggests that gender-and occupation-specific strategies and policies to reduce work-related stress can prevent suicide among workers.

Background: There is limited research on the heterogeneity of worker suicides. We compared differences in workers’ suicides by clustering suicide deaths. Methods: From 2010 to 2017, 353 suicide deaths were claimed in the Industrial Accident Compensation Insurance; variables were coded using a standardized methodology. A two-step cluster analysis classified the clusters based on demographic and employment conditions. Details of the suicide, clinical variables, personal stresses, and work-related stresses were compared using the chi-square test and one-way analysis of variance. Results: We identified five clusters and they differed particularly in work-related stress. “Responsibility-burdened type” experienced excessive responsibility as managers; “role-changed type” experienced a sudden and unpredictable role change as clerks or sales workers; “risk-exposed type” experienced physical risk factors at work (working alone, outdoors, and in shifts) as machine operating and assembling workers, or craft and related trades workers; “job-insecurity type” experienced unstable employment (irregular, nonpermanent) as elementary or service workers; “workplace-violence type” was mainly unmarried women who lived alone, and experienced interpersonal conflict and violence as professionals and related workers. There were no differences between clusters in clinical variables (except problem drinking) and personal stresses. Conclusion: Interventions to alleviate work-related stress in worker clusters are needed to prevent suicide in workers.

Although studies on occupational mortality have been conducted in Korea, the results for occupations with high mortality around 2010 are inconsistent. This study aimed to examine occupational mortality from overwork-related suicide and cerebro-cardiovascular diseases (CCVD) from 1997 to 2020. We used microdata of the Causes of Death Statistics (CDS) and Economically Active Population Survey (EAPS) to obtain indirect standardized mortality ratio (SMR) and standardized proportional mortality ratio (PMR) of suicide (X60–X84) and CCVD deaths (I20–I25 and I60–I69) by gender and eight occupational categories. The trend of SMR of suicide and CCVD by occupation was similar within individual genders. The SMR of managers (MNG) was the highest for men and women in 2012–2017 and 2008–2020, respectively, whereas the SMR of professionals and related workers (PRF) was consistently low. Despite the similar socioeconomic status of MNG and PRF, we suggest that their mortality should be analyzed separately in Korea. SMR of suicide and CCVD in female MNG were consistently highest, although the PMR was low. Female MNG may have been more directly affected by the economic crisis. There is a need for work-related stress management, early intervention, and prevention policies in occupations vulnerable to mortality.