• Proceedings of the KOSOMBE Conference
• /
• v.1992 no.05
• /
• pp.181-183
• /
• 1992

90일간에 걸쳐 수집된 후천성 맹인의 체온데이타를 분석하였다. 이 데이타는 1일 주기 리듬을 갖고 있음을 잘 보여주었으며, 데이타 분석 방법으로는 시계열분석을 이용, 잡음을 제거하고 푸리에분석방법에 의하여 추정데이타를 만든후, 원 데이타와의 오차 자승항이 최소가 되는 주기를 찾는 방법을 사용하였다. 전체 데이타를 1일, 3일, 5일씩의 길이로 잘라서 분석을 하였으며 90여일에 걸친 분석 결과들을 모아 추정파형의 진폭과 서카디안 페이즈를 그래프로 도시하였다. 고찰결과, 1. 이 맹인의 체온데이타는 24, 25시간의 일정한 주기를 갖고있다. 2. 이 데이타는 24시간의 주기와 24, 25시간의 주기로 분리할 수 있다. 3. 따라서 1일 주기리듬의 체온데이타는 근소한 차이의 두 가지 성분이 존재함을 알 수 있다.라는 결론을 내릴 수 있었다.

• Journal of Life Science
• /
• v.28 no.8
• /
• pp.985-991
• /
• 2018

Biological clocks are the basis of temporal control of metabolism and behavior. These clocks are characterized by autonomous free-running oscillation and temperature compensation and are found in animals, plants, and microorganisms. To date, various biological clocks have been reported. These include clocks governing hibernation, sleep/wake, heartbeat, and courtship song. These clocks can be differentiated by the period of rhythms, for example, infradian rhythms (> 24-hr period), circadian rhythms (24-hr period), and ultradian rhythms (< 24-hr period). In yeast (Saccharomyces cerevisiae), at least five different autonomous oscillations have been reported; (1) glycolytic oscillations (T = 1~30 min), (2) cell cycle-dependent oscillations (T = 2~16 hr), (3) ultradian metabolic oscillations (T = 15~50 min), (4) yeast colony oscillations (T = a few hours), and (5) circadian oscillations (T = 24 hr). In this review, we discuss studies on oscillators, pacemakers, and synchronizers, in addition to the application of biological clocks, to demonstrate the nature of autonomous oscillations, especially ultradian metabolic oscillations of S. cerevisiae.

• Child Health Nursing Research
• /
• v.18 no.2
• /
• pp.85-94
• /
• 2012

Purpose: Instead of a chaotic non circadian environmental approach, continuing regular day-night rhythm in neonatal nurseries may benefit the development of preterm infants. The purpose of this study was to define the effects of cycled lighting on circadian rhythms of premature infants. Methods: The experimental group included 15 preterm infants, and the control group, 15 premature infants in the NICU of a general hospital in Seoul. All infants were between 32 and 37 weeks' postconceptional age. The experimental group infants were provided with cycled lighting before discharge. The incubator or bassinet cover of the experimental group was off between 7 AM and 7 PM, and was covered between 7 PM and 7 AM. Results: There were significant differences in the NNNS score ($p$=.039), and some significant differences in the sleep-activity pattern between the experimental group and the control group, but distinct differences in sleep-activity patterns between the two groups could not be defined. Conclusion: The results of this study suggest that cycled lighting can be helpful in the neurobehavioral development of preterm infants. By modifying the NICU environment to provide a more developmentally supportive milieu, nursing professionals can better meet the infants' physiologic and neurobehavioral needs.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.13 no.2
• /
• pp.63-71
• /
• 2005

There is a concern in the aviation community that pilot schedules can lead to fatigue and increased chance of an aviation accident. Yet despite this concern, there is little empirical studies showing the relationship between pilot fatigue and commercial aviation accidents. At this point of view, countering fatigue is a challenging proposition in complex aviation operations. However, with appropriate planning, many strategies can contribute to pilot alertness and flight safety. With proper education program, sustaining a physiological fit, a right knowledge about pilot fatigue can design a safety operations. On this study, I inquire into the ways of enhancing pilot's efficiency from fatigue.

• Korean journal of applied entomology
• /
• v.24 no.2 s.63
• /
• pp.71-77
• /
• 1985

The male activity in Laspeyresia pomonella (L.) measured by an activity recording device in New York had two distinct peaks, the first peak at lights-off and the second one at ligts-on signal, under the defined conditions of temperature above $23^{\circ}C$ and light:dark (LD) 16:8 regime. The activity initiation of the first activity was observed four to six hours prior to the onset of scotophase and seened to be entraind by lights-off cue. Under the continuous photophase (LL) the activity period freeran with a period slightly greater than 24 hours, indicating that the rhythmicity is circadian The activity pattern was measured in eight different temperature conditions ranging from $11.3^{\circ}\;to\;30^{\circ}C$ under LD 16:8 regime. No activity was observed at $11.3^{\circ}C$ which seems to be temperature threshold for activity. The second peak of activity at lights-on signal disappeared at the temperature below $20^{\circ}C$ and the activity in scotophase was also suppressed at the temperature lower than $18^{\circ}C$. At the temperature range from $20^{\circ}\;to\;30^{\circ}C$, as temperature increased the second peak in the morning became larger and the activty in the scotophase was also increased. Because of the activity increase in the scotophase with rising temperature, the mean time of activity shifted towards the scotophase. The shift of the moth male activity period with the change of ambient temperature appears to be due to the suppression of activity under cool temperature (below $20^{\circ}C$) in scotophase.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.40 no.5
• /
• pp.556-561
• /
• 1995

Persisent circadian rhythms in carbon assimilation, stomatal conductance and soluble carbohydrate concentration were investigated during grain filling period in rice plant transferred from a natural photoperiod to constant conditions. A weak rhythm in photosynthesis, measured as carbon assimilation, and stomatal opening, as conductance to water vapor, with a period of approximately 24-hours, occurred under constant condition. Carbon assimilation and stomatal conductance reached maximum values near noon and minimum values near midnight during the early stage (until 72-hour) after transferring to constant condition, and then the amplitude and phase were changed slowly, the rhythms with little damping, reaching maximum values near midnight and minimum values near noon during 96~120-hours after transferring. However, photosynthesis in plants grown for 14days after anthesis under constant moderate light(day and night) did not oscillated in constant condition unlike plants grown under a cycle of light and darkness. These phenomenon was observed in soluble carbohydrate concentration in flag leaves as well. Evidences from several approaches indicate that endogenous rhythms of $CO_2$ assimilation, stomatal conductance and soluble carbohydrate concentration are closely couped with each other and particularly important to plants, which depend on the natural day-night cycle as a external signal.

• Sleep Medicine and Psychophysiology
• /
• v.7 no.2
• /
• pp.115-119
• /
• 2000

Objectives Summary: A 20-year-old man was presented with a history of difficult waking for 10 years. He suffered from morning headache, chronic fatigue and mild daytime sleepiness but had no history of irresistible sleep attack, cataplexy, hypnagogic hallucination or sleep paralysis. Methods: Night polysomnography (PSG), multiple sleep latency test (MSLT) and HLA-typing were carried out. Results: The PSG showed short sleep latency (4.0 min) and REM latency (2.5 min), increased arousal index (15.7/hour), periodic limb movements during sleep (PLMS index=8.1/hr) with movement arousal index 2.1/hr and normal sleep efficiency (97.5%). The MSLT revealed normal sleep latency (15 min 21 sec) and 4 times sleep-onset REM (SOREM). HLA-typing showed DQ6- positive, that corresponded at the genomic level to the subregion DQB1*0601, which was different from the usual locus in narcolepsy patients (DQB1*0602 and DQA1*0102). Conclusion: Differential diagnosis should be made with circadian rhythm disorder and other causes of primary waking disorder. The possibility of a variant type of narcolepsy could be suggested with an unusual clinical manifestation and a new genetic marker.

• Journal of Life Science
• /
• v.22 no.8
• /
• pp.999-1008
• /
• 2012

The circadian clock is a self-sustaining 24-hour timekeeper that allows organisms to anticipate daily-changing environmental time cues. Circadian clock genes are regulated by a transcriptional-translational feedback loop. In Arabidopsis, LATE ELONGATED HYPOCOTYL (LHY) and CIRCADIAN CLOCK-ASSOCIATED 1 (CCA1) transcripts are highly expressed in the morning. Translated LHY and CCA1 proteins repress the expression of the TIMING OF CAB EXPRESSION 1 (TOC1) transcripts, which peaks in the evening. The TOC1 protein elevates the expression of the LHY and CCA1 transcripts, forming a negative feedback loop that is believed to constitute the oscillatory mechanism of the clock. In mammals, the transcription factor protein CLOCK, which is a central component of the circadian clock, was reported to have an intrinsic histone acetyltransferase (HAT) activity, suggesting that histone acetylation is important for core clock mechanisms. However, little is known about the components necessary for the histone acetylation of the Arabidopsis clock-related genes. Here, I report that DET1 (De-Etiolated1) functions as a negative regulator of a key component of the Arabidopsis circadian clock gene LHY in constant dark phases (DD) and is required for the down-regulation of LHY expression through the acetylation of histone 3 (H3Ac). However, the HATs directly responsible for the acetylation of H3 within LHY chromatin need to be identified, and a link connecting the HATs and DET1 protein is still absent.

• The Bulletin of The Korean Astronomical Society
• /
• v.39 no.1
• /
• pp.89.1-89.1
• /
• 2014

빛공해란, 불필요하거나 필요 이상의 인공빛이 야생 동식물들과 우리 인간들에게 악영향을 미치는 현상을 말하며, 실생활에서 인공빛 에너지를 목적에 맞지 않게 사용하는 것이 이 현상의 주요 원인이라고 할 수 있다. 빛공해 현상은 야생 동식물들에게 악영향을 주어 개체수를 감소시킬뿐만 아니라 멸종에까지 이르게 할 수 있으며, 지구 자전의 영향으로 하루 24시간 주기로 설정되어 있는 우리 인간의 생체리듬을 교란시켜 암, 비만, 당뇨병, 그리고 우울증 등과 같은 인간의 목숨을 위협할 수 있는 질병들을 일으키기도 한다. 하지만 인공빛을 목적에 맞게 올바르게 사용한다면 그로 인해 절약된 에너지와 그 비용을 다른 필요한 분야에 대체하여 사용할 수 있을 것이다. 우리는 과거의 빛공해 관련 논문과 보고서의 설문조사 결과를 통하여 빛공해로 인한 피해와 에너지 낭비 문제가 빛공해에 대한 일반 시민들의 무관심으로부터 발생하고 있다는 사실을 확인할 수 있었다. 따라서 우리는 빛공해에 대한 일반 시민들의 인식 변화를 알아보기 위하여 기존에 진행된 설문조사와 같은 문답내용의 설문조사를 올해 다시 실시하였다. 그 설문조사의 결과를 통하여 우리는 과거보다 빛공해에 대한 인식이 많이 확산되어 있다는 사실을 알 수 있었으며, 그 이유로는 최근 빛공해와 관련된 많은 뉴스 기사들과 함께 웹상의 소셜네트워크와 같은 다양한 경로의 정보매체들을 통하여 빛공해에 대한 정보를 보다 빠르고 쉽게 접할 수 있는 환경이 조성되었기 때문이라고 분석하였다. 빛공해 인식 확산에 더욱 더 기여하기 위하여 최근에 우리는 국제 어두운 밤하늘 협회 한국 지부 (Korean Chapter, International Dark-Sky Association) 인가를 받아 그 단체 이름으로 빛공해 방지 홍보 사업을 온라인과 오프라인을 통하여 보다 더 활발히 진행하기 위하여 많은 노력을 하고 있다.

• Sleep Medicine and Psychophysiology
• /
• v.6 no.1
• /
• pp.76-84
• /
• 1999

Objectives: A number of studies have shown that sleep deprivation results in reduced vigilance and increased negative affects such as tension, depression and anger. However there are few studies about effects of sleep deprivation on anxiety. The purpose of this study was to investigate the effects of 40 hour sleep deprivation on state anxiety, affects, sleepiness and fatigue. The authors also intended to study the effect of trait-anxiety on these psychological variables after sleep deprivation. Methods: Twenty nine subjects(22 men, 7 women, $24.59{\pm}1.35$ years of age) participated in this study. Subjects had no past history of psychiatric disorders and physical illnesses, and had normal sleep-waking cycle without current sleep disturbances. All of the subjects completed sleep dairy for two weeks to exclude some who suffered from chronic sleep deprivation or sleep disturbances. Subjects were instructed to get a normal sleep as usual at night before the study. After awakening, subjects remained awake for 40 hours under continuous surveillance. They completed State-Trait Anxiety Inventory, Index of General Affect, Stanford Sleepiness Scale and Fatigue Questionnaire every three hours, therefore they completed the scales 14 times totally. Subjects were dictated not to take caffeine, alcohol, or any medications on the day of the study. Heavy exercises and naps were restricted too. Results: Sleep deprivation resulted in increased state anxiety, negative general affects, and increased sleepiness and fatigue(p<.001). Dividing into high trait-anxiety group and low trait-anxiety group, there was significant sleep deprivation x traitanxiety interaction effect on general affect(p<.05). But, there was no significant sleep deprivation x trait-anxiety interaction effect on state-anxiety, sleepiness and fatigue. During sleep deprivation, the highest ratings of scales on anxiety, negative affect, sleepiness and fatigue occurred between 4 : 00AM and 7 : 00AM. Conclusions: These results show that sleep deprivation results in increased anxiety, mood state disturbance and increment of sleepiness and fatigue. These findings also suggest that trait-anxiety is a factor that influences the degree of worsening in general affect caused by sleep deprivation. During sleep deprivation, the rating curves of anxiety, affect, sleepiness and fatigue show rhythmicity that may be related to circadian rhythm.