• Safety and Health at Work
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• v.13 no.3
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• pp.269-278
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• 2022

Background: PTSD (Post-traumatic stress disorder, PTSD) had a great impact on health care workers during the COVID-19 (Corona Virus Disease 2019, COVID-19). Better knowledge of the prevalence of PTSD and its risk factors is a major public health problem. This study was conducted to assess the prevalence and important risk factors of PTSD among medical staff during the COVID-19. Methods: The databases were searched for studies published during the COVID-19, and a PRISMA (preferred reporting items for systematic review and meta-analysis) compliant systematic review (PROSPERO-CRD 42021278970) was carried out to identify articles from multiple databases reporting the prevalence of PTSD outcomes among medical staff. Proportion random effect analysis, I² statistic, quality assessment, subgroup analysis, and sensitivity analysis were carried out. Results: A total of 28 cross-sectional studies and the PTSD results of doctors and nurses were summarized from 14 and 27 studies: the prevalences were 31% (95% CI [confidence interval, CI]: 21%-40%) and 38% (95% CI: 30%-45%) in doctors and nurses, respectively. The results also showed seven risks (p < 0.05): long working hours, isolation wards, COVID-19 symptoms, nurses, women, fear of infection, and pre-existing mental illness. Two factors were of borderline significance: higher professional titles and married. Conclusion: Health care workers have a higher prevalence of PTSD during COVID-19. Health departments should provide targeted preventive measures for medical staff away from PTSD.

• Nutrition Research and Practice
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• v.18 no.2
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• pp.269-281
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• 2024

BACKGROUND/OBJECTIVES: The objective of this study was to compare dietary habits and mental health among middle school students in urban and rural areas based on bedtime, and to provide evidence supporting appropriate bedtime for Korean middle school students in relation to their healthy dietary habits and mental well-being. SUBJECTS/METHODS: The study population consisted of 25,681 second-year middle school students who participated in the Korea Youth Risk Behavior Survey in 2020-2022. Participants were asked about their bedtime and wake-up time during the past 7 days and were classified into five categories. The study compared the general characteristics, academic factors, dietary habits, and mental health of urban and rural students based on their bedtime. RESULTS: Bedtime was found to be later in the following order: urban female students, rural female students, urban male students, and rural male students. As bedtime got later, the rates of smoking and alcohol consumption increased. Students who went to bed before 11 p.m. had lower academic performance, while rural male students who went to bed after 2 a.m. had lower academic performance. Later bedtime was associated with increased smartphone usage, skipping breakfast, consuming fast food, and drinking carbonated beverages. Later bedtime was also associated with higher perceived stress levels, particularly among students who went to bed after 2 a.m., higher rates of suicidal ideation, experiencing sadness and despair, as well as the prevalence of clinically significant anxiety disorders. CONCLUSION: These results suggest that middle school students who go to bed too late have higher rates of smoking and alcohol drinking, as well as unhealthy eating habits, stress, suicidal ideation, sadness, and anxiety. Therefore, it is necessary to provide educational and social institutional support to promote adequate sleep for the health of adolescents.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.10 no.4
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• pp.177-184
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• 2015

The purpose of this study was to investigate the effect that the job stress of employees would have on the organization effectiveness. In this study, 222 employees in Seoul and Gyeonggi province were surveyed from March to May, 2015 through empirical research with the structured questionnaires, and the collected data were statistically computerized under a statistical package of SPSS 18.0 and analyzed based on the correlation analysis, frequency analysis, and multiple regression analysis. The Following results were derived. First, the job stress of employees according to demographic characteristics had a significance difference. The technical employees had the lower role ambiguity of job stress compare to other group and the higher the income years and educational background, the higher the role overload of job stress. Second, the job stress of employees had a negative effect on the job satisfaction and Organization effectiveness but a positive effect on the turnover intention and the hypothesis was adopted. Thus, it turned out that the job stress of employees had a significant effect on the organization effectiveness and there was a significance at the statistical level. Based on this research finding, it is considered necessary to seek the specific measures that can help reduce the turnover rate of employees and improve their job satisfaction and organization commitment in a more effective methods.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.133-133
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• 2017

Lodging is one of the important constraints in rice production. The lodging destroys the canopy structure, and sharply reduces the capacity of photosynthetic rate and dry matter production. In cereal crops, stem lodging can be classified into two types: stem breaking type and stem bending type. To improve stem lodging resistance, it is important to reveal strong culm traits of superior lodging resistant varieties. There are large varietal differences in parameters associated with the bending moment at breaking (M) and flexural rigidity (FR). The indica variety Takanari possesses large M due to its large section modulus (SM) despite of its small bending stress (BS), while Takanari also has large FR due to its large secondary moment of inertia (SMI) and Young's modulus (YM). To identify quantitative trait loci (QTLs) and the corresponding genes associated with the parameters for M ($=SM{\times}BS$) and FR ($=SM{\times}YM$) should enable to develop lodging resistant varieties, efficiently. In order to identify QTLs for cell wall materials such as cellulose, hemicellulose and lignin associated with BS and YM, a set of Chromosome Segment of Substitution Lines (CSSLs) consisted of 37 lines with chromosome segments of Koshihikari in the genetic background of Takanari were used. Takanari had large M and small BS as compared with Koshihikari. The QTLs for BS were estimated on chromosomes 3, 5, 6, 8, 9, 10, 11 and 12. Koshihikari alleles increased BS in these QTLs. Takanari had a large FR due to its large SMI and YM as compared with Koshihikari. The YM was increased by substitution of the Koshihikari chromosomal segments on chromosomes 2, 10 and 11. Other QTLs estimated on chromosomes 7 and 12 that Koshihikari alleles contributed to the decrease of YM. For lignin, only one major QTL for lignin density was detected on chromosome 11. Hollocellulose densities were increased by the substitution of Koshihikari segments on chromosomes 5 and 11. On the other hand, these were decreased on chromosomes 1 and 3 by substitution of Koshihikari segments. QTLs for cellulose density were estimated on chromosomes 1, 3 and 5 by substitution of Koshihikari segments. For hemicellulose, QTL on chromosome 3 showed that hemicellulose density decreased by the substitution of Koshihikari segment. However, hemicellulose densities on chromosomes 5, 8 and 11 showed the opposite effects. The QTLs for hemicellulose, cellulose, and hollocelulose densities identified on chromosome 5 overlapped with that for bending stress, indicating the positive effect of Koshihikari segment on increasing bending stress. These results suggest that some QTLs for the densities of cell wall materials contribute to increasing bending stress and Young's modulus, and could be utilized to improve the lodging resistance for both types of breaking and bending in rice varieties.

• Safety and Health at Work
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• v.8 no.3
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• pp.276-281
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• 2017

Background: The present study was carried out to assess the relationship between sickness absence and occupational stress, sleep quality, and amplitude and stability of circadian rhythm as well as to determine contributing factors of sickness absence. Methods: This cross sectional study was conducted on 400 randomly selected employees of an Iranian gas company. The data were collected using Pittsburgh sleep quality index, Karolinska sleepiness scale, circadian type inventory, and Osipow occupational stress questionnaires. Results: The mean age and job tenure of the participants were $33.18{\pm}5.64years$ and $6.06{\pm}4.99years$, respectively. Also, the participants had been absent from work on average 2.16 days a year. According to the results, 209 participants had no absences, 129 participants had short-term absences, and 62 participants had long-term absences. The results showed a significant relationship between short-term absenteeism and amplitude of circadian rhythm [odds ratio (OR) = 6.13], sleep quality (OR = 14.46), sleepiness (OR = 2.08), role boundary (OR = 6.45), and responsibility (OR = 5.23). Long-term absenteeism was also significantly associated with amplitude of circadian rhythm (OR = 2.42), sleep quality (OR = 21.56), sleepiness (OR = 6.44), role overload (OR = 4.84), role boundary (OR = 4.27), and responsibility (OR = 3.72). Conclusion: The results revealed that poor sleep quality, amplitude of circadian rhythm, and occupational stress were the contributing factors for sickness absence in the study population.

• Korean Journal of Community Nutrition
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• v.7 no.4
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• pp.506-515
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• 2002

This study examined the state of health and weight maintenance according to the body mass index (BMI) , and explored demographic variables, diet variables, the degree of stress etc. The results presented were based on data collected from 428 women who are mothers of the middle school children in Jeongeup city. Using SPSS WIN (Ver 9.0) , the frequency, percentage, mean, standard deviation, chi-square, ANOVA, and correlation analysis were provided. The mean of BMI for the subjects was 22.6, the ratio of obese women (BMI $\geq$ 25) was 22.9%. The frequency of the reported circulation or respiratory related diseases was greater in the obese group compared to the normal weight ($20 \leq BMI \leq 25$) or the lean (BMI < 20) groups. The obese group had less awareness of obesity. Those who regard themselves obese had lower rates of satisfaction with their body shape and higher rates of interest in weight control. Approximately 65% of the subjects attempted weight reduction more than once. Subjects who were obese had the most undesirable dietary behavior. In particular, this group had the higher rates of rushed meals, overeating, meals while watching TV or newspapers, and snacking, and eating out. In analyzing the correlation of variables influencing obesity, there were positive correlations between obesity and overeating, obesity and the degree of stress. Correlations between obesity and satisfaction for life found to be negative. Moreover, stress had a positive correlation with obesity and overeating, and showed negative correlation with eating behavior. Consequently, stress seemed to induce undesirable eating behaviors and increase obesity. Of the demographic background variables, subjects who were obese tended to be older, had lower levels of education, higher rates of employment, longer period of marriage, the higher number of children, preschool children or children preparing for highschool or college, lower satisfaction with children and household life.

• Journal of Ginseng Research
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• v.45 no.6
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• pp.654-664
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• 2021

Background: Ginsenoside Rg3, isolated from Panax ginseng, has anti-inflammatory and anti-tumor activities. It is known to reduce inflammation in acute lung injury in mice, and to reduce the expression of inflammatory cytokines and COX-2 in human asthmatic airway epithelium. In this study, we attempted to determine whether ginsenoside Rg3 inhibits airway inflammation, oxidative stress, and airway hyperresponsiveness (AHR) in the lungs of asthmatic mice. We also investigated its effects on oxidative stress and the inflammatory response in tracheal epithelial cells. Methods: Asthma symptoms were induced in female BALB/c mice sensitized with ovalbumin (OVA). Mice were divided into five groups: normal controls, OVA-induced asthmatic controls, and asthmatic mice treated with ginsenoside Rg3 or prednisolone by intraperitoneal injection. Inflammatory BEAS-2B cells (human tracheal epithelial cells) treated with ginsenoside Rg3 to investigate its effects on inflammatory cytokines and oxidative responses. Results: Ginsenoside Rg3 treatment significantly reduced eosinophil infiltration, oxidative responses, airway inflammation, and AHR in the lungs of asthmatic mice. Ginsenoside Rg3 reduced Th2 cytokine and chemokine levels in bronchoalveolar lavage fluids and lung. Inflammatory BEAS-2B cells treated with ginsenoside Rg3 reduced the eotaxin and pro-inflammatory cytokine expressions, and monocyte adherence to BEAS-2B cells was significantly reduced as a result of decreased ICAM-1 expression. Furthermore, ginsenoside Rg3 reduced the expression of reactive oxygen species in inflammatory BEAS-2B cells. Conclusion: Ginsenoside Rg3 is a potential immunomodulator that can ameliorate pathological features of asthma by decreasing oxidative stress and inflammation

• Journal of dental hygiene science
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• v.22 no.3
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• pp.164-170
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• 2022

Background: When cells are damaged by nicotine, cellular senescence due to oxidative stress accelerates. In addition, stress-induced inflammatory response and cellular senescence cause the accumulation of damaged organelles in cells, and autophagy appears to remove them. Conversely, when autophagy is reduced, harmful cell components accumulate, and aging is accelerated. This study aimed to determine the association between nicotine-induced cellular senescence and autophagy expression patterns in human gingival fibroblasts. Methods: Cells were treated with various concentrations of nicotine (0, 0.1, 0.5, 1, 2, and 5 mM) and 10 nM rapamycin was added to 1 mM nicotine to investigate the relationship between autophagy and cellular senescence. Cell viability was confirmed using WST-8 and the degree of cellular senescence was measured by SA-β-gal staining. The expression of the inflammatory proteins (COX-2 and iNOS) and autophagy markers (LC3-II, p62, and Beclin-1) was analyzed by western blotting. Results: The cell viability tended to decrease in a concentration-dependent manner. COX-2 showed no concentration-dependent expression and iNOS increased in the 0.5 mM nicotine treated group. The degree of cellular senescence was the highest in the 1 mM nicotine treatment group. In the group treated with rapamycin and nicotine, the conversion ratio of LC3-II to LC3-I was the highest, that of p62 was the lowest, and the level of Beclin-1 proteins was significantly increased. Furthermore, the degree of cellular senescence was reduced in the group in which rapamycin was added to nicotine compared to that in the group treated with nicotine alone. Conclusion: This study provides evidence that autophagy activated in an aging environment reduces cellular senescence to a certain some extent.

• Journal of dental hygiene science
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• v.19 no.4
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• pp.271-278
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• 2019

Background: This study aimed to examine the factors that influence clinical performance of dental hygiene students to provide useful data for developing strategies to improve clinical competence. Methods: The effects of variables on clinical competence by quantile level were analyzed using quantile regression analysis in 247 dental hygiene students. Quantile regression and multiple regression analyses were conducted using the Stata 11.0 program to analyze predictors of clinical competence. Results: The clinical competence score of dental hygiene students was 42.69±5.90, the satisfaction of clinical practice was 49.90±7.44, the clinical practice stress was 50.62±7.37, and the professional self-concept was 31.68±4.41. Empathy was the highest at 50.87±4.93. Multiple regression analysis showed that school year, stress from clinical training, satisfaction with clinical training, professional self-concept, and empathy had significant impact on clinical competence. Quantile regression analysis showed that the effects varied depending on the clinical competence level. School year and professional self-concept had a significant positive effect, regardless of the clinical competence level, while empathy had a significant positive effect at the top 10% (Q90) of the clinical competence level. Satisfaction with clinical practice affected clinical competence at Q25, Q50, and Q90. Stress from clinical practice had significant effects at Q25, Q50, and Q90 (p<0.05). Conclusion: According to the study results, different factors affected clinical competence according to the quantile of clinical competence. This study provides valuable implications for designing clinical competence enhancement programs and strategies. In addition, objective indicators for considering factors that may affect the clinical competence, such as academic competence and satisfaction of practice hospitals, are expected to require detailed analysis and measures.

• Korean Journal of Materials Research
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• v.24 no.6
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• pp.326-337
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• 2014

The use of solar energy generation is steadily increasing, and photovoltaic modules are connected in series to generate higher voltage and power. However, solar panels are exposed to high-voltage stress (up to several hundreds of volts) between grounded module frames and the solar cells. Frequent high-voltage stress causes a power-drop in the modules, and this kind of degradation is called potential induced degradation (PID). Due to PID, a significant loss of power and performance has been reported in recent years. Many groups have suggested how to prevent or reduce PID, and have tried to determine the origin and mechanism of PID. Even so, the mechanism of PID is still unclear. This paper is focused on understanding the PID of crystalline-silicon solar cells and modules. A background for PID, as well as overviews of research on factors accelerating PID, mechanisms involving sodium ions, PID test methods, and possible solutions to the problem of PID, are covered in this paper.