Data-Driven Enhancement of ZT in SnSe-Based Thermoelectric Systems.

Doping and alloying are fundamental strategies to improve the thermoelectric performance of bare materials. However, identifying outstanding elements and compositions for the development of high-performance thermoelectric materials is challenging. In this study, we present a data-driven approach to improve the thermoelectric performance of SnSe compounds with various doping. Based on the newly generated experimental and computational dataset, we built highly accurate predictive models of thermoelectric properties of doped SnSe compounds. A well-designed feature vector consisting of the chemical properties of a single atom and the electronic structures of a solid plays a key role in achieving accurate predictions for unknown doping elements. Using the machine learning predictive models and calculated map of the solubility limit for each dopant, we rapidly screened high-dimensional material spaces of doped SnSe and evaluated their thermoelectric properties. This data-driven search provided overall strategies to optimize and improve the thermoelectric properties of doped SnSe compounds. In particular, we identified five dopant candidate elements (Ge, Pb, Y, Cd, and As) that provided a high ZT exceeding 2.0 and proposed a design principle for improving the ZT by Sn vacancies depending on the doping elements. Based on the search, we proposed yttrium as a new high-ZT dopant for SnSe with experimental confirmations. Our research is expected to lead to novel high-ZT thermoelectric material candidates and provide cutting-edge research strategies for materials design and extraction of design principles through data-driven research.

Synthesis of Fluorescent Au Nanocrystals-Silica Hybrid Nanocomposite (FLASH) with Enhanced Optical Features for Bioimaging and Photodynamic Activity.

Fluorescent Au nanocrystals (AuNCs)-silica hybrid nanocomposite (FLASH) was synthesized by co-condensation of surface-modified AuNCs. Present FLASH nanocomposite exhibited four times the enhanced photoluminescence and photocatalytic activity compared to single nanocrystals. On the basis of these enhanced optical features, we successfully demonstrated in vitro fluorescence bioimaging of introduced FLASH to human cervical cancer cell line (HeLa). Beyond the confirmation of photocatalytic activity from the photodegradation of methylene blue as a model compound, the regional selective photodynamic therapy of HeLa cells under UV irradiation was also presented. Taken together the enhanced optical features and further potential in theranostic applications, we expect that the present FLASH can be a promising tool for nanobiotechnology field.

Long working hours may increase risk of coronary heart disease.

OBJECTIVE: To evaluate the association between long working hours and risk of coronary heart disease (CHD) estimated by Framingham risk score (FRS) in Korean adults. METHODS: This study evaluated adult participants in Korean National Health and Nutrition Examination Survey IV (2007-2009). After inclusion and exclusion criteria were applied, the final sample size for this study model was 8,350. Subjects were asked about working hours and health status. Participants also completed physical examinations and biochemical measurement necessary for estimation of FRS. Multiple logistic regression was conducted to investigate the association between working hours and 10-year risk for CHD estimated by FRS. RESULTS: Compared to those who work 31-40 hr, significantly higher 10-year risk was estimated among subjects working longer hours. As working hours increased, odds ratio (OR) for upper 10 percent of estimated 10-year risk for CHD was increased up to 1.94. CONCLUSIONS: Long working hours are significantly related to risk of coronary heart disease.

Increased breast cancer incidence among nurses in a tertiary university hospital in South Korea.

Background: A series of breast cancer cases were recently reported in a tertiary university hospital in South Korea. Nurses are generally exposed to risk factors for breast cancer such as night shift work, antineoplastic agents, and job strain. However, the epidemiological evidence of excess incidence among nurses remains lacking. This study aims to investigate the excess incidence of breast cancer among nurses in a tertiary university hospital and provide epidemiological evidence of occupational risk factors. Methods: A retrospective cohort was developed using personnel records of female workers in the nursing department who worked from January 2011 to June 2021 in a tertiary university hospital in South Korea. Sick leave records were used to identify cases of breast cancer. The standardized incidence ratio of breast cancer among nurses was compared to the general population. Results: A total of 5,509 nurses were followed up for 30,404 person-years, and 26 breast cancer cases were identified. This study revealed a significantly increased breast cancer incidence among all included nurses, with a standardized incidence ratio of 1.65 (95% confidence interval [CI]: 1.08-2.41), compared to the general population. Workers, who handle antineoplastic agents in their representative department and current and/or former department, had significantly elevated breast cancer standardized incidence ratios of 2.73 (95% CI: 1.008-5.94) and 3.39 (95% CI: 1.46-6.68), respectively. Conclusions: This study provides significant evidence of increased breast cancer risk among nursing staff in a hospital setting, particularly those who handle antineoplastic drugs. Measures that reduce exposure to risk factors should be implemented, especially anticancer drugs, to protect healthcare professionals. Further research at a national level that focuses on healthcare workers is necessary to validate breast cancer incidence and its contributing factors.

Relationship Between Emotional Labor and Perceived Health Status Among Service and Sales Workers: Findings From the Korea National Health and Nutrition Examination Survey 2007 to 2009.

OBJECTIVES: This study examined the relationship between emotional labor and general health status in a nationally representative sample of South Korean service and sales workers. METHODS: Data were obtained from the 2007 to 2009 Korea National Health and Nutrition Examination Survey. A total of 1907 subjects were included in the analysis. Multiple logistic regression was performed to determine the relationship between emotional labor and perceived health status (PHS). RESULTS: The adjusted odds ratio (95% confidence interval) of poor PHS was 1.869 (1.464 to 2.391) among high emotional labor group, compared with the low emotional labor group as the reference. Perceived stress accounted for 35.57% of the variance in the relationship between high emotional labor and poor PHS. CONCLUSIONS: Emotional labor was associated with increased risk of poor PHS.

Self-Rated Health Trajectory Changes According to Employment Transition: A Korean Prospective Cohort Study.

OBJECTIVE: To investigate the impact of employment transitions on self-rated health (SRH) trajectories. METHODS: We used data from the Korean Labor and Income Panel Study 2003 to 2016. Employment transitions were measured using four categories: continuously non-working, continuously working, labor force exit, and labor force entry. For examination of the time trends in the likelihood of poor SRH, we calculated the annual odds ratios with those from 2003 as the reference, using generalized estimating equations. RESULTS: The time trends in the likelihood of poor SRH showed a significant increasing trend in the labor force exit group, while continuously working group and labor force entry group showed significantly decreasing patterns. CONCLUSIONS: Labor force exit was associated with a substantial increase in prevalence of poor SRH, while labor force entry was associated with a decrease in prevalence of that.

Effect of Socioeconomic Factors on the Relationship Between Musculoskeletal Pain and Ill-Health Retirement in Korea: Results From the Korean Longitudinal Study of Aging.

OBJECTIVE: To investigate the relationship between musculoskeletal pain (MSP) and ill-health retirement (IHR) and modifying role of socioeconomic factors. METHODS: The data used were samples from the Korean Longitudinal Study of Aging from 2006 to 2014. IHR was defined as retirement due to health problems before regular retirement age. Hazard ratio (HR) was calculated using Cox proportional hazards model to determine the effects of MSP and covariance on IHR. RESULTS: People who have "any site of pain" were more likely to experience IHR than people with no pain. In the subgroup analysis, risk of IHR due to MSP was higher in the 60s, white-collar, and high-income earners than the other groups. CONCLUSIONS: MSP has a substantial negative impact on labor force participation, and there was a clear effect modification of socioeconomic status on IHR risk.

The Impact of Working Hours on Cardiovascular Diseases and Moderating Effects of Sex and Type of Work: Results From a Longitudinal Analysis of the Korean Working Population.

OBJECTIVES: The aim of this study was to estimate the risk of cardiovascular disease (CVD) caused by working hours in the South Korean working population stratified by sex and type of work. METHODS: We analyzed longitudinal data from the Korean Longitudinal Study of Aging in 2006. The risk of CVD associated with working hours was estimated using Cox regression analysis. In addition, the analysis was conducted by stratifying the sample by sex and type of work (wage work and self-employment). RESULTS: After adjusting for all covariates, subjects in long working hours (≥50 h/wk) groups showed increased risk of CVD. After sex and type of work stratification, only women and wageworkers showed significantly increased risk of CVD associated with long working hours. CONCLUSIONS: The results demonstrated that increased risk of CVD was associated with long working hours, especially in women and wageworkers.

Mental disorders among workers in the healthcare industry: 2014 national health insurance data.

BACKGROUND: Numerous studies have shown that healthcare professionals are exposed to psychological distress. However, since most of these studies assessed psychological distress using self-reporting questionnaires, the magnitude of the problem is largely unknown. We evaluated the risks of mood disorders, anxiety disorders, sleep disorders, and any psychiatric disorders in workers in healthcare industry using Korea National Health Insurance (NHI) claims data from 2014, which are based on actual diagnoses instead of self-evaluation. METHODS: We used Korea 2014 NHI claims data and classified employees as workers in the healthcare industry, based on companies in the NHI database that were registered with hospitals, clinics, public healthcare, and other medical services. To estimate the standardized prevalence of the selected mental health disorders, we calculated the prevalence of diseases in each age group and sex using the age distribution of the Korea population. To compare the risk of selected mental disorders among workers in the healthcare industry with those in other industries, we considered age, sex, and income quartile characteristics and conducted propensity scored matching. RESULTS: In the matching study, workers in healthcare industry had higher odds ratios for mood disorders (1.13, 95% CI: 1.11-1.15), anxiety disorders (1.15, 95% CI: 1.13-1.17), sleep disorders (2.21, 95% CI: 2.18-2.24), and any psychiatric disorders (1.44, 95% CI: 1.43-1.46) than the reference group did. Among workers in healthcare industry, females had higher prevalence of psychiatric disorders than males, but the odds ratios for psychiatric disorders, compared to the reference group, were higher in male workers in healthcare industry than in females. CONCLUSIONS: The prevalence of mood disorders, anxiety disorders, sleep disorders, and all psychiatric disorders for workers in the healthcare industry was higher than that of other Korean workers. The strikingly high prevalence of sleep disorders could be related to the frequent night-shifts in these professions. The high prevalence of mental health problems among workers in healthcare industry is alarming and requires prompt action to protect the health of the "protectors."

Association between urinary 3-phenoxybenzoic acid and body mass index in Korean adults: 1(st) Korean National Environmental Health Survey.

BACKGROUND: According to US-EPA report, the use of pyrethrins and pyrethroids has increased during the past decade, and their area of use included not only in agricultural settings, but in commerce, and individual household. It is known that urinary 3-PBA, major metabolite of pyrethroid, have some associations with health effect in nervous and endocrine system, however, there's no known evidence that urinary 3-PBA have associations with obesity. METHOD: We used data of 3671 participants aged above 19 from the Korean National Environmental Health Survey in 2009-2011. In our analysis, multivariate piece-wise regression and logistic regression analysis were used to investigate the association between urinary 3-PBA (3-Phenoxybenzoic Acid) and BMI. RESULT: Log-transformed level of urinary 3-PBA had significantly positive association with BMI at the low-level range of exposure (p < 0.0001), and opposite associations were observed at the high level exposure (p = 0.04) after adjusting covariates. In piece-wise regression analysis, the flexion point that changes direction of the associations was at around 4 ug/g creatinine of urinary 3-PBA. As quintiles based on concentration of urinary 3-PBA increased to Q4, the ORs for prevalence of overweight (BMI ≥ 23 kg/m(2)) were increased, and the OR of Q5 was lower than that of Q4 (OR = 1.810 for Q4; OR = 1.483 for Q5). In the analysis using obesity (BMI ≥ 25 kg/m(2)) as outcome variable, significant associations were observed between obesity and quintiles of 3-PBA, however, there were no differences between the OR of Q5 and that of Q4 (OR = 1.659 for Q4; OR = 1.666 for Q5). CONCLUSION: Our analysis suggested that low-level of pyrethroid exposure has positive association with BMI, however, there is an inverse relationship above the urinary 3-PBA level at 4 ug/g creatinine.

Computer use at work is associated with self-reported depressive and anxiety disorder.

BACKGROUND: With the development of technology, extensive use of computers in the workplace is prevalent and increases efficiency. However, computer users are facing new harmful working conditions with high workloads and longer hours. This study aimed to investigate the association between computer use at work and self-reported depressive and anxiety disorder (DAD) in a nationally representative sample of South Korean workers. METHODS: This cross-sectional study was based on the third Korean Working Conditions Survey (2011), and 48,850 workers were analyzed. Information about computer use and DAD was obtained from a self-administered questionnaire. We investigated the relation between computer use at work and DAD using logistic regression. RESULTS: The 12-month prevalence of DAD in computer-using workers was 1.46 %. After adjustment for socio-demographic factors, the odds ratio for DAD was higher in workers using computers more than 75 % of their workday (OR 1.69, 95 % CI 1.30-2.20) than in workers using computers less than 50 % of their shift. After stratifying by working hours, computer use for over 75 % of the work time was significantly associated with increased odds of DAD in 20-39, 41-50, 51-60, and over 60 working hours per week. After stratifying by occupation, education, and job status, computer use for more than 75 % of the work time was related with higher odds of DAD in sales and service workers, those with high school and college education, and those who were self-employed and employers. CONCLUSIONS: A high proportion of computer use at work may be associated with depressive and anxiety disorder. This finding suggests the necessity of a work guideline to help the workers suffering from high computer use at work.

The effect of long working hours on 10-year risk of coronary heart disease and stroke in the Korean population: the Korea National Health and Nutrition Examination Survey (KNHANES), 2007 to 2013.

BACKGROUND: Recently, the emergence of long working hours and the associated conditions such as coronary heart disease (CHD) and stroke have gained attention. The aim of this study was to investigate the association between long working hours and the 10-year-risk of CHD and stroke, estimated by Jee's health risk-appraisal model for ischemic heart disease. METHODS: We analyzed data from Koreans who randomly enrolled in Korean National Health and Nutrition Examination Survey 2008-2012 and finally included 13,799 participants. The participants were classified as per their working hours: 0-30 h/week, 31-39 h/week, 40 h/week, 41-50 h/week, 51-60 h/week, 61-70 h/week, 71-80 h/week, and >80 h/week. The risks for CHD and stroke were determined using Jee's health risk-appraisal model. Multiple logistic regression was used to analyze the association between working hours and 10-year risk for CHD. RESULTS: The 10-year risks for CHD and stroke were significantly and positively associated with working hours in both men and women. Furthermore, higher risks for CHD and stroke were associated with longer working hours in women. CONCLUSION: Long working hours are significantly associated with the risks of CHD and stroke, estimated by Jee's health risk-appraisal model. This study suggests the need for proper management of working hours to reduce CHD risk and stroke risk in the Korean population.