• Safety and Health at Work
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• 제15권1호
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• pp.102-109
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• 2024

Background: In today's modern world, longer working hours, shift work, and working at night have become major causes of the disruption of our natural circadian rhythms. This study aimed to investigate the effects of the type of shift work (rotating vs. fixed day), duty period (on-duty vs. off-duty), and working period within each shift (nighttime vs. daytime) on the circadian rhythm characteristics of nurses who provide direct patient care. Methods: This cross-sectional study used a purposive sampling method. Cosinor analysis was applied to analyze the actigraphy data of nurses providing direct patient care for seven consecutive days. The linear mixed effects model was then used to determine any variances between shift type, duty period, and working period within each shift for the nurses. Results: The mesor value did not differ according to nurses' shift type, duty period, and working period within each shift. The amplitude was statistically higher in on-duty nurses and in daytime working hours. The acrophase was significantly delayed in nighttime working hours. As well as nurses in rotating shift had experience. Conclusion: Our findings revealed that the peak activity of nurses occurs significantly later at night while working and nurses working during nighttime hours may have a weaker or less distinct circadian rhythm. Thus, this study suggests that limits be placed on the number of rotating nighttime shifts for nurses.

• 한국콘텐츠학회논문지
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• 제14권8호
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• pp.319-328
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• 2014

본 연구는 대학생들의 일주기 리듬, 학습몰입 및 피로를 조사하고 일주기 리듬 유형에 따른 학습몰입과 피로의 차이를 파악하기 위한 것이다. 본 연구는 서술적 조사 설계를 이용하였으며 연구대상자는 5개 대학에 재학 중인 224명의 학생을 대상으로 편의표집 하였다. 자료는 2013년 5월부터 6월 사이에 Morningness-Eveningness Questionnaire-Korean(MEQ-K), 몰입상태척도, 피로사정척도를 이용하여 조사하였다. 조사결과 대상자의 51.8%가 중간형이었으며, 아침형은 4.0%로 나타났다. 일주기 리듬 유형에 따른 학습몰입과 피로의 차이를 비교한 결과 아침형에 비해 저녁형이 학습몰입의 정도는 낮은 반면 피로의 정도는 높았다. MEQ-K 도구를 이용하여 구분한 일주기 리듬 유형과 대상자 스스로가 평가한 자신의 일주기 리듬 유형을 비교하였을 때 대상자의 32.1%에서 두 가지 유형이 일치하지 않았다. 따라서 대학생들이 자신의 일주기 리듬을 실제와 다르게 인식할 경우 잘못된 인식으로 일주기 리듬과 실제 생활리듬이 불일치할 가능성이 있으므로 대학생들이 자신의 일주기 리듬을 정확하게 이해할 수 있는 중재프로그램이 필요한 것으로 판단된다.

• 기술사
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• 제15권4호
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• pp.32-36
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• 1982

• Ocean Science Journal
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• 제43권2호
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• pp.107-113
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• 2008

Laboratory bioassays were conducted to test the acute toxicity effects of sudden exposure to sodium cyanide (NaCN) on the endogenous rhythm of the oxygen consumption rate (OCR) in the black rockfish Sebastes schlegeli. The OCR of the black rockfish(n = 14, total length = $20.4{\pm}1.16\;cm$, wet weight = $158{\pm}25\;g$) was measured with an automatic intermittent-flow-respirometer. OCR decreased significantly when experimental fish were exposed to NaCN. When exposed to 10 ppb NaCN, fish were able to recover their OCR rhythmic activities. When fish were exposed to 20 ppb, however, the metabolic activity rhythms were not recovered. These results suggest that exposure to NaCN concentrations over 20 ppb cause severe physiological damage to the endogenous rhythms of black rockfish.

• Journal of Chest Surgery
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• 제28권6호
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• pp.579-582
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• 1995

The extended transseptal approach to the mitral valve replacement has been used for 30 patients. There were 19 women and 11 men. Twenty five patients had rheumatic heart disease, 4 had degenerative valve ,and 1 had valve prolapse. Fifteen of 30 patients had other associated procedure; 10 had aortic valve replacement; 5 had tricuspid annuloplasty. There were no postoperative complications associated with the approaches, ie, no bleeding, no sinus node dysfuction, and no atrioventricular conduction disturbance. Despite division of the sinus node artery, preoperative atrial rhythms[3 sinus rhythms and 27 atrial fibrillations were not changed during postoperative period. The extended transseptal approach provides good mitral valve exposure without inherent complications, and is superior to that of standard approach, so we use it routinely for mitral valve procedure.

• 대한음성학회지:말소리
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• 제40호
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• pp.29-49
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• 2000

This study has two aim: one is to clarify the restructuring of English in utterance and the other is to make use of text-setting to be applied to getting accustomed to the English rhythm and pronunciation. Clitics prove to play a crucial role on the English restructuring, and are found to be attached to their previous and to their next head or host, thus forming, respectively, an on-cliticized rhythm, trochee and a pro-cliticized rhythm, iambus. En-cliticization proves to be preferred to pro-cliticization in most types of English rhythms. Accordingly, the restructuring turn out to occur all over the levels of the Prosodic Hierarchy. That is, syllables, words and clitic groups are restructured in poetry as well as in song words, which means the necessity of restructuring throughout the levels of the Prosodic Hierarchy from the syllable to the utterance. The present study suggests a good use of a rhythmic textsetting for learners of English to get accustomed to the stress-timed rhythm as well as to such changes in pronunciation as reductions, deletions, resolutions, contractions, and rhythms in English.

• Molecules and Cells
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• 제28권2호
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• pp.75-80
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• 2009

The cyclic environmental conditions brought about by the 24 h rotation of the earth have allowed the evolution of endogenous circadian clocks that control the temporal alignment of behaviour and physiology, including the uptake and processing of nutrients. Both metabolic and circadian regulatory systems are built upon a complex feedback network connecting centres of the central nervous system and different peripheral tissues. Emerging evidence suggests that circadian clock function is closely linked to metabolic homeostasis and that rhythm disruption can contribute to the development of metabolic disease. At the same time, metabolic processes feed back into the circadian clock, affecting clock gene expression and timing of behaviour. In this review, we summarize the experimental evidence for this bimodal interaction, with a focus on the molecular mechanisms mediating this exchange, and outline the implications for clock-based and metabolic diseases.

• 한국식품영양과학회지
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• 제13권2호
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• pp.222-228
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• 1984

Since organisms have their rhythms by synchronizing the changes of periodic external circumstances and maintaining the integration of internal ones, circadian rhythm which affects to ingestion, digestion and metabolism of nutrients in the body, is important and interesting to discuss in the field of nutritional science. Also it is a serious public health problem tat various night-shift jobs are increasing now a days. Therefore authors wish to understand the properties of circadian rhythm and the rhythms of metabolic activities.

• 통합자연과학논문집
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• 제5권3호
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• pp.198-210
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• 2012

Circadian rhythms govern a remarkable variety of metabolic and physiological functions. Accumulating epidemiological and genetic evidence indicates that the disruption of circadian rhythms might be directly linked to cancer. Intriguingly, several molecular gears constituting the clock machinery have been found to establish functional interplays with regulators of the cell cycle, and alterations in clock function could lead to aberrant cellular proliferation. In addition, connections between the circadian clock and cellular metabolism have been identified that are regulated by chromatin remodelling. This suggests that abnormal metabolism in cancer could also be a consequence of a disrupted circadian clock. Therefore, a comprehensive understanding of the molecular links that connect the circadian clock to the cell cycle and metabolism could provide therapeutic benefit against certain human neoplasias.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 2002년도 학술발표대회
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• pp.62-62
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• 2002