• Safety and Health at Work
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• v.2 no.1
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• pp.1-8
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• 2011

The knowledge on the etiology of breast cancer has advanced substantially in recent years, and several etiological factors are now firmly established. However, very few new discoveries have been made in relation to occupational risk factors. The International Agency for Research on Cancer has evaluated over 900 different exposures or agents to-date to determine whether they are carcinogenic to humans. These evaluations are published as a series of Monographs (www.iarc.fr). For breast cancer the following substances have been classified as "carcinogenic to humans" (Group 1): alcoholic beverages, exposure to diethylstilbestrol, estrogen-progestogen contraceptives, estrogen-progestogen hormone replacement therapy and exposure to X-radiation and gamma-radiation (in special populations such as atomic bomb survivors, medical patients, and in-utero exposure). Ethylene oxide is also classified as a Group 1 carcinogen, although the evidence for carcinogenicity in epidemiologic studies, and specifically for the human breast, is limited. The classification "probably carcinogenic to humans" (Group 2A) includes estrogen hormone replacement therapy, tobacco smoking, and shift work involving circadian disruption, including work as a flight attendant. If the association between shift work and breast cancer, the most common female cancer, is confirmed, shift work could become the leading cause of occupational cancer in women.

• Sleep Medicine and Psychophysiology
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• v.1 no.1
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• pp.3-8
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• 1994

With the recent development of sleep medicine, insomnia has been perceived as a disease from a simple symptom. As there are various causes in a disease, proper treatment according to each cause is necessary for a more effective treatment In general, insomnia is classified into five categrories of physical, physiological, psychological, psychiatric and pharmacological aspects. However, such categorizations are often insufficient in treating insomnia. Furthermore understanding of the developmental mechanisms of insomnia is required. The function of sleep is developed and maintained through the balance of the reciprocal forces of sleep and arousal. These forces are contantly regulated by what is called a circadian rhythm. Sleep is induced by this rhythm which is affected by factors such as awakening time in the morning, amount of intellectual function, amount and time length of physical exercise and sunlight Insomnia could develop when this rhythm is delayed and leads to a "forbidden zone" which is a very difficult period for inducing sleep about two to four hours before the routine bedtime. Whereas sleep gradually develops in line with the circardian rhythm, arousal can occur very abruptly by any cause triggered by emotional discomfort or anxiety. Such characteristic and emotional factors as perfectionism, separation anxiety, secondary gain, insecurity, and negative cognition may provoke the inner anxiety and fear for insomnia, which can lead acute insomnia to a chronic one. As chronic insomnia is developed by multiple causes and factors, integrated approaches through analysis of above mentioned factors will be more effective in the treatment of insomnia than a simple administration of hypnotics.

• Journal of The Korea Institute of Healthcare Architecture
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• v.28 no.4
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• pp.71-87
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• 2022

Purpose: This study examines the daylighting design factors of Korean dementia nursing homes, in order to realize a therapeutic environment based on the therapeutic effect of light in the rapidly aging trend with an huge increase in the population of dementia in Korea. Methods: Through literature reviews, this study aims to theoretically examine the therapeutic light environment for the elderly with dementia, derive daylighting design factors of Korean dementia nursing homes, and analyze their detailed design factors. Results: The result of this study can be summarized into two points. The first one is that the daylighting design factors reflected in dementia nursing homes are derived into six factors: building layout, windows, glazing, shading devices, spaces, and interior finishings that determine the availability of daylight. The second one is that the detailed daylighting design factors are shown as primary and secondary detailed design factors, and the main values to be considered when applying these factors into dementia nursing homes are analyzed as maximizing daylight availability, optimization of the possibility of therapeutic view, and anti-glare. Implications: The daylighting design factors will contribute to maximizing the availability of daylight, optimizing the possibility of view, and minimizing the glare in the living spaces of dementia nursing homes in Korea.

• Journal of Korean Academy of Nursing
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• v.48 no.5
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• pp.622-635
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• 2018

Purpose: This study aimed to develop and test a structural model for sleep quality in female shift work nurses. The hypothetical model was constructed on the basis of Spielman's 3P model of insomnia and previous research related to the sleep quality of shift nurses. Methods: This cross-sectional study used structural equation modeling and recruited 285 female shift work nurses from four general and university hospitals with over 300 beds located in C and J cities in Gyeongsangnamdo. Data were collected from September 27 to October 20, 2016, and then analyzed using descriptive statistics, Pearson's correlation, and structural equation modeling. The study used SPSS/Win 18.0 and AMOS 18.0 in processing the data. Results: The final model showed good fit to the empirical data: ${\chi}^2/df=2.19$, SRMR=.07, RMSEA=.07, AGFI=.85, TLI=.91, GFI=.93, GFI=.89, NFI=.87. The factors that influenced sleep quality were sleep hygiene (${\beta}=.32$), perceived shift work status (${\beta}=-.16$), stress response (${\beta}=.16$), shift work experience (${\beta}=.15$), perceived health status (${\beta}=-.14)$, and circadian rhythm (${\beta}=-.13$) explaining 36.0% of the variance. Conclusion: The model of sleep quality of the shift work nurses constructed in this study is recommended as a model to understand and predict the sleep quality of shift work nurses. The results suggest that strategies for improving the sleep quality of shift work nurses should focus on sleep hygiene, perceived health status, stress response, circadian rhythm, perceived shift work status, and shift work experience.

• Molecules and Cells
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• v.39 no.8
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• pp.587-593
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• 2016

As sessile organisms, plants must be able to adapt to the environment. Plants respond to the environment by adjusting their growth and development, which is mediated by sophisticated signaling networks that integrate multiple environmental and endogenous signals. Recently, increasing evidence has shown that a bHLH transcription factor PIF4 plays a major role in the multiple signal integration for plant growth regulation. PIF4 is a positive regulator in cell elongation and its activity is regulated by various environmental signals, including light and temperature, and hormonal signals, including auxin, gibberellic acid and brassinosteroid, both transcriptionally and post-translationally. Moreover, recent studies have shown that the circadian clock and metabolic status regulate endogenous PIF4 level. The PIF4 transcription factor cooperatively regulates the target genes involved in cell elongation with hormone-regulated transcription factors. Therefore, PIF4 is a key integrator of multiple signaling pathways, which optimizes growth in the environment. This review will discuss our current understanding of the PIF4-mediated signaling networks that control plant growth.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2006.06a
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• pp.41-42
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• 2006

• Korean journal of aerospace and environmental medicine
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• v.30 no.2
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• pp.61-65
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• 2020

In the case of aviation maintenance work, several kinds of shift works are performed during day and night, and a lot of works are performed on the ramp due to the characteristics of the aircraft flight schedule. Maintenance workers are often exposed to the sun or in cold temperatures for aircraft maintenance works. The fatigue risk of the maintenance workers will be weighted. In particular, the work at night shift under normal biological rhythms can make maintenance workers feel sleepy during daytime work. It can also affect the safety of aircraft and individual workers. Accordingly, this study will consider fatigue-related previous researches in the field of aviation maintenance, review the effects of shift work, and how fatigue affects aviation mechanics during the day/night shifts. Considering these factors, we tried to present a plan that can minimize the fatigue of aviation workers through this study.

• Sleep Medicine and Psychophysiology
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• v.30 no.1
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• pp.13-21
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• 2023

The Seasonal Affective Disorder (SAD) is a disorder characterized by prolonged periods of depression and various physical and psychological symptoms experienced during specific seasons, typically winter. In this review aims to provide a comprehensive overview of SAD with a specific focus on psychophysiological aspects. Through the review from ancient times to the present, this paper explores the characteristics, causes, and underlying mechanisms of SAD. Particularly, it comprehensively reviews the research findings on the relationship between external factors such as light, sunlight, climate, and their association with SAD. Furthermore, the paper discusses the interplay between SAD and psychophysiological changes, along with the latest research trends in treatment and prevention strategies. By combining theoretical and practical perspectives on SAD, this article aims to provide a holistic understanding and offer suggestions for future research directions and clinical interventions.

• Fisheries and Aquatic Sciences
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• v.4 no.3
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• pp.138-143
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• 2001

Red sea bream, Pagrus major a fish species characterized by its dualistic feeding pattern, was investigated to study the synchronizing effect of light and food on the demand-feeding rhythm. Nocturnal and diurnal red sea bream, both in groups and individually, were exposed to restricted-feeding and Light-Dark cycles of different periods. The phase relationship between both zeitgebers was also studied. In some cases, food availability restricted to the light or dark phase contrary to that of the previous feeding phase changed a diurnal feeding pattern into nocturnal and vice versa, suggesting that food can be one of the switching factors that decides whether the circadian system of red sea bream is diurnal or nocturnal. However, the fact that the feeding pattern of some fish was unrelated with the phase in which food was available suggests that other internal and/or external-factors could be involved in the temporal flexibility of red sea bream.

• Korean Journal of Occupational Health Nursing
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• v.25 no.4
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• pp.373-383
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• 2016

Purpose: The purpose of this study was to identify the factors affecting shiftwork tolerance among nurses and provide basic data, ultimately, in formulating a plan for improving their shiftwork tolerance. Methods: The participants were 317 nurses who were working at three general hospitals in Daejeon and Seoul. Data analyzed t-test, ANOVA, correlation analysis, and regression analysis using SPSS 20.0 program. Results: As for the sub-areas of shiftwork tolerance for the respondents, more than a half of nurses working at shifts suffered from insomnia, felt drowsy, complained of chronic fatigue, and were at the anxious and depressed state. Shiftwork tolerance differed by the daily intake of coffee and exercise. Shiftwork tolerance was significantly positively correlated with sleep-wake habits, hardiness, and flexibility and negatively correlated with a languidity. Regression analysis revealed that shiftwork tolerance was affected by age, sleep-wake habits, languidity, flexibility, and hardiness. Conclusion: To put the results, nurses had shiftwork tolerance affected by sleep-wake habits, languidity, and hardiness. It is therefore necessary to make a scheme for allowing nurses to improve hardiness and flexibility and decrease the languidity with the objective of improving their shiftwork tolerance.