• Journal of Photoscience
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• 제9권2호
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• pp.252-254
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• 2002

Djungarian hamsters show distinct seasonal rhythms in several physiological parameters. One of them is daily torpor that occurs in winter with decreased body temperature (about 1O-20$^{\circ}$C) during daytime. Daily torpor is induced by short-day photoperiod, food restriction and castration. But the mechanism to induce daily torpor has not been clarified. In the present study, we tried to clarify the process of daily torpor induction in detail. Adult male hamsters were kept in long photoperiod and high temperature (LP-HT) before the experiment and, thereafter, the animals were transferred to short photoperiod and low temperature (SP-LT), and they were kept in this condition for about six months. The daily rhythms of locomotor activity and body temperature were recorded every three-minutes by using the Minimitter telemetry system. Locomotor activity and body temperature showed very closely synchronized rhythms. All animals under LP-HT showed daily rhythms with higher locomotor activity and body temperature in nighttime than in daytime. Under SP-LT, there were two types of animals with and without showing daily torpor. Thus, they have individual differences in the response to SP -LT.

• 수면정신생리
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• 제21권2호
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• pp.51-60
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• 2014

A 'circadian rhythm' is a self-sustained biological rhythm (cycle) that repeats itself approximately every 24 hours. Circadian rhythms are generated by an internal clock, or pacemaker, and persist even in the absence of environmental time cues, collectively termed 'zeitgebers.' Although organisms generate circadian rhythms internally, they are entrained by environmental stimuli, particularly the light-dark cycle. Measurement of the endogenous melatonin rhythm provides relatively reliable surrogate way of assessing the timing of the internal circadian clock. Also, core body temperature and cortisol can be used as markers of circadian rhythms. The sleep-wake cycle, body temperature, and melatonin rhythm have a stable internal phase relationship in humans and other diurnal species. They play an important role in controlling daily behavioral rhythms including task performance, blood pressure, and synthesis and secretion of several hormones. In this review, we address not only the properties, methods of measurement, and markers of circadian rhythms, but also the physiological and psychological importance of human circadian rhythms.

• Molecules and Cells
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• 제43권7호
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• pp.600-606
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• 2020

Numerous physiological processes in nature have multiple oscillations within 24 h, that is, ultradian rhythms. Compared to the circadian rhythm, which has a period of approximately one day, these short oscillations range from seconds to hours, and the mechanisms underlying ultradian rhythms remain largely unknown. This review aims to explore and emphasize the implications of ultradian rhythms and their underlying regulations. Reproduction and developmental processes show ultradian rhythms, and these physiological systems can be regulated by short biological rhythms. Specifically, we recently uncovered synchronized calcium oscillations in the organotypic culture of hypothalamic arcuate nucleus (ARN) kisspeptin neurons that regulate reproduction. Synchronized calcium oscillations were dependent on voltage-gated ion channel-mediated action potentials and were repressed by chemogenetic inhibition, suggesting that the network within the ARN and between the kisspeptin population mediates the oscillation. This minireview describes that ultradian rhythms are a general theme that underlies biological features, with special reference to calcium oscillations in the hypothalamic ARN from a developmental perspective. We expect that more attention to these oscillations might provide insight into physiological or developmental mechanisms, since many oscillatory features in nature still remain to be explored.

• 대한의용생체공학회:의공학회지
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• 제5권1호
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• pp.33-38
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• 1984

Biological rhythms are very important phenomena to generate, grow a living thing. However, the origin of rhythms are not disclosed completely until now. Eack myocardial cell has a natural rhythm of itself, and synchronization is happened when two cells are come in contact with each other. In this research, a simple synchronization model has been proposed and studied, refering to the physiological model. The changes of the synchronization rhythms in experimental results are compared with that of the model.

• 수면정신생리
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• 제5권1호
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• pp.34-44
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• 1998

Living organisms are influenced by many external rhythms and they have adapted their physiology to periodically changing conditions. These adaptive strategies are controlled by endogenous innate programs of behavior and physiology which are determined by external signals ("Zeitgeber"). There are many biological rhythms, each with its own characteristic functional adaptation. Among them, the presence of endogenous time control of feeding and drinking becomes obvious. There are increasing evidences that the control of food intake, food selection, and drinking are regulated by the endogenous rhythms including a circadian rhythm. However, there have been many restrictions in understanding the endogenous control of food intake itself and its mechanism. To broaden our know ledges of the endogenous time control of feeding and drinking, the author reviwed the characteristics of the endogenous timing for food intake, the influence of circadian pacemakers and food-entrainable oscillators, the interaction between the circadian control and the external and internal conditions in the control of food intake, the conseqences of feeding, the circadian control of food selection, and the biological cycles in energy balance.

• Journal of Photoscience
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• 제9권2호
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• pp.249-251
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• 2002

The avian pineal as well as the retina has been known to contain several types of photoreceptors with different visual pigments such as rhodopsin, iodopsin and the pineal specific opsin, pinopsin. These organs are also known to have circadian clock to regulate melatonin production. Exposure of animals to light causes a decline of the melatonin level and the phase shifts of melatonin rhythms in the pineal and retina. Therefore, the circadian clock system of these organs seem to consist of three elements, i.e., light input, oscillator and melatonin output systems. In birds, it was suggested that rhodopsin might be involved in the entrainment of pineal melatonin rhythms from the action spectrum experiment for controlling NAT activity rhythms. However, there are much more pinopsin-immunoreactive (Pino-IR) cells than rhodopsin (Rho-IR) and iodopsin (Iodo-IR) cells in the avian pineal. We found that Pino-IR cells appeared earlier embryonic stages than Rho-IR and Iodo-IR cells. So, we tried to identify the visual pigments involved in the circadian melatonin rhythms in the pineal and retina. Organ cultured pineals were exposed to monochromatic light to find out which opsin participates in regulation of melatonin rhythms. The action spectra showed a peak at 475nm, suggesting that pinopsin is the major photopigment to regulate melatonin production in birds.

• 한국실내디자인학회논문집
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• 제24권2호
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• pp.78-87
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• 2015

This study aims to grasp the vital rhythm of the Chapel at Ronchamp by analyzing its rhythm through Henri Lefebvre's 'rhythmanalysis' in an effort to show the possibility of approaching the presence of this chapel. For the purpose of this study, Lefebvre's thought of rhythmanalysis was first contemplated, and a case study analysis was conducted on the concept and presence of the chapel in the design process. On this basis, examples of the chapel's rhythms were analyzed through Lefebvre's dialectical analysis of the triad of time(melody), space(harmony) and energy(rhythm). The results of analysis are as follows: First, the concept intended by Le Corbusier in the process of designing the Chapel at Ronchamp is expressed as the acoustic form, the modulor corresponding to the scale of the music, the light and shadow of counterpoint, and the opposite composition of musical changes. Consequently, the concept-mediated presence of this chapel is the presence of music. Second, at the Chapel at Ronchamp, a Lefebvre's rhythmanalyst experiences, or rather senses, two vital rhythms of an antithetical unity (i.e., acoustic curved rhythm and modulor-generated linear rhythm), with reference to his/her own rhythms. These rhythms are a dialectical union of spatiality of melodies temporalized through continuity, (i.e., acoustic curved form and modulor-generated linear form), and temporality of harmonies spatialized through simultaneity (i.e., light and shadow, materials and color, form of interpenetration, and stairs or windows/doors). These rhythms carry the measures generated by music-specific repetitions and differences in movements(energy). Consequently, the rhythm-mediated presence of this chapel is also the presence of music. In conclusion, the Chapel of Ronchamp indicates that an approach toward its presence can be realized through vital rhythms derived from Lefebvre's 'rhythmanalysis'. This study holds significance as an analysis of spatial rhythm and presence, employing a philosophical thought.

• 한국엔터테인먼트산업학회논문지
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• 제13권6호
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• pp.45-52
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• 2019

본 논문은 국내 아이돌 그룹 중 3세대 걸 그룹을 중심으로 하여 리듬의 분석과 분포 양상에 초점을 맞추고 있다. 장르의 발전과 리듬의 융, 복합은 계속되어지고 있으며 세계적으로도 라틴음악의 리듬이 강세를 보이고 있다. 이러한 현상은 세계의 음악시장뿐 아니라 국내 대중가요의 장르 중 아이돌 댄스 음악에서도 동일하게 나타고 있음을 알 수 있다. 본 논문은 라틴 음악의 리듬중 하나인 뎀보우 리듬과 트레실로 리듬이 3세대 아이돌 음악에 중점적으로 나타나고 있는 현상에 주목하여 특정한 수의 조합이 리듬과 멜로디에 나타나는 현상을 연구하였다. 3세대 걸 그룹의 곡들 중 연구의 대상에 해당하는 12곡의 분석을 통하여 사용 되어진 리듬의 기원과 구조, 사용 사례를 확인하여 비교 분석하였다. 3세대 걸 그룹의 12곡을 분석한 결과 뎀보우 리듬이 사용된 곡은 5곡 트레실로 리듬이 사용된 곡은 8곡으로 확인되었으며 뎀보우 리듬은 16비트에서만 사용 가능하지만 트레실로 리듬은 8분음표와 16분음표 모두 사용 가능하다는 것을 알 수 있었다.

• 생물정신의학
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• 제2권2호
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• pp.266-274
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• 1995

We invesigated whether the circadian rhythms of plasma MHPG and HVA concentrations exist in 11 healthy young adults, and analyzed the patterns of their circadian rhythms. The results were as follows : 1) The change in the mean plasma MHPG concentrations analyzed by repeated measures ANOVA was not statistically significant. Five subjects showed significant circadian rhythms of plasma MHPG concentrations of each individual, and 4 of those had the acrophases between 17PM and 24PM. 2) The change in the mean plasma HVA concentrations analyzed by repeated measures ANOVA was not statistically significant. Six subjects showed significant circadian rhythms of plasma HVA concentrations of each individual, and 4 of those had the acrophases between 21PM and 6AM. In conclusion, the circadian rhythm pattern of plasma HVA concentrations in our result is consistent with the previous study. It was suggested that plasma MHPG and HVA concentrations should be measured more frequently, and the physical activities of subjects be controlled more strictly for the following study.

• 한국패류학회지
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• 제15권2호
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• pp.127-131
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• 1999

전북 곰소만에 서식하는 바지락의 생리적 리듬을 알아보기 위하여 24시간 동안 1시간 간격으로 산소소비율 및 여수율의 변화를 측정하였다. 바지락의 호흡율 및 여수율에 의한 생리적 리듬은 15$^{\circ}C$와 $25^{\circ}C$에서 두 가지 모두 24시간 동안 2번의 peak를 보이는데, 밤-만조시에 최대를 나타내었으며, 낮-간조시에 최소를 나타내어 조석에 의한 일주리듬 현상을 보였다. 24시간 동안 산소소비율 및 여수율의 변화는 수온별로 급격한 특수한 변화를 보이지 않았다.