• Journal of Photoscience
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• 제9권2호
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• pp.9-12
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• 2002

Circadian rhythms can be seen in a variety of physiological functions in insects. Light is a powerful zeitgeber not only synchronizing but also modulating the rhythm to adjust insect's temporal structure to seasonal changes in the environmental cycle. There are two general effects of the length of light phase within 24 hr light cycles on the circadian rhythms, i.e., the modulation of free-running period and the waveform. Since the photoperiodic modulation of the free-running period is induced even in the clock mutant flies, per$\^$s/, the free-running period is not fully determined genetically. In crickets, the ratio of activity (a) and rest phase (p) under the constant darkness (DD) is clearly dependent on the photoperiod under which they have been kept. When experienced the longer photoperiod it becomes smaller. The magnitude of change in a/p-ratio is dependent on the number of cycles they experienced. The neuronal activity of the optic lobe in DD shows the a/p-ratio changing with the preceding photoperiod. These data suggest that a single circadian pacemaker stores and maintains the photoperiodic information and that there is a system that accumulates the effects of single photoperiod to cause greater effects.

• Molecules and Cells
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• 제42권4호
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• pp.301-312
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• 2019

Post-transcriptional regulation underlies the circadian control of gene expression and animal behaviors. However, the role of mRNA surveillance via the nonsense-mediated mRNA decay (NMD) pathway in circadian rhythms remains elusive. Here, we report that Drosophila NMD pathway acts in a subset of circadian pacemaker neurons to maintain robust 24 h rhythms of free-running locomotor activity. RNA interference-mediated depletion of key NMD factors in timeless-expressing clock cells decreased the amplitude of circadian locomotor behaviors. Transgenic manipulation of the NMD pathway in clock neurons expressing a neuropeptide PIGMENT-DISPERSING FACTOR (PDF) was sufficient to dampen or lengthen free-running locomotor rhythms. Confocal imaging of a transgenic NMD reporter revealed that arrhythmic Clock mutants exhibited stronger NMD activity in PDF-expressing neurons than wild-type. We further found that hypomorphic mutations in Suppressor with morphogenetic effect on genitalia 5 (Smg5) or Smg6 impaired circadian behaviors. These NMD mutants normally developed PDF-expressing clock neurons and displayed daily oscillations in the transcript levels of core clock genes. By contrast, the loss of Smg5 or Smg6 function affected the relative transcript levels of cAMP response element-binding protein B (CrebB) in an isoform-specific manner. Moreover, the overexpression of a transcriptional repressor form of CrebB rescued free-running locomotor rhythms in Smg5-depleted flies. These data demonstrate that CrebB is a rate-limiting substrate of the genetic NMD pathway important for the behavioral output of circadian clocks in Drosophila.

• 국제물리치료학회지
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• 제4권2호
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• pp.562-565
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• 2013

The fact that flip-flops, one of many different types of unstable shoes, are light and relatively easy to put on, accounts for their popularity among people. But because flip-flops rely heavily on the support of a single thong between your first and second toes, they impose a huge amount of pressure onto lower leg. Thus in the following experiment we tried to examine the different effects of flip-flops and running shoes in terms of their effect on muscle activity and fatigue of tibialis anterior and gastrocnemius during walking. In order to measure an electromyogram we used Free EMG system. 10 men and 10 women in running shoes ran on treadmills for 15 minutes at 4.8km/h, 2 days later the same experiment was carried out, but this time, in flip-flops. p value turned out to be greater than .05 and thus there was no considerable difference between the effects of flip-flops and running shoes on muscle activity and fatigue during walking. Therefore we conclude that despite the fact that flip-flops are considered unstable, their effects on muscle activity and fatigue of tibialis anterior and gastrocnemius are negligible.

• 대한지역사회영양학회지
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• 제28권1호
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• pp.24-37
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• 2023

Objectives: This study aimed to investigate the current status of nutrition education via a free learning semester program (NE). The understanding of the program, the potential difficulties, and future initiatives for NE improvement were also investigated. Methods: A total number of 161 nutrition teachers from Gwangju and Jeonnam filled in a questionnaire and participated in this survey, which was performed from July to August 2019. Results: Our results showed that 8.1% of the nutrition teachers had taught nutrition education in free learning semester programs. The most frequently implemented model was subject selection, followed by club activities. Most of the nutrition teachers comprehended the purpose of NE. The attitude of nutrition teachers to NE differed by the understanding of its purpose. Positive attitude was evident due to a better understanding of the purpose by nutrition teachers. Nutrition teachers reported the most common difficulties of NE were the lack of preparation due to the heavy workload and the lack of a standard running program. The most effective method of NE was the activity classes. The experience of practicing NE influenced the choice of contents for each operating model. Nutrition teachers that were experienced in NE conducted via free learning semester programs preferred the selected topics model, but those without experience chose the career search model. Conclusions: Although some obstacles exist, nutrition teachers had a positive attitude and perceived well the importance of NE. Therefore, the awareness for the significance of NE of nutrition teachers needs to be improved. For better NE practice, it is necessary to reduce/ manage the workload of general food service. Furthermore, the development of standard running and promotion programs, and teacher training programs should be ensured.

• 약학회지
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• 제39권1호
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• pp.48-54
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• 1995

Coupling of tetracycline(Tc) to dithiocarbamate chitosan(DTCC) via chelate bond was investigated varying reaction time, concentration, temperature, pH, and Ca(II)/Tc ratio. The amount of Tc bound to matrix increased to give a maximum and decreased as the reaction proceeded. The degree and rate of dissociation of Tc complex were affected by the reaction temperature, and pH. By running the reaction at low temperature and pH, the degree of dissociation was greatly diminished. Properties of drug-release from DTCC-Ca(II)-Tc complex were studied by batch- and flow-method and release of Tc and CA(II) by flow method followed nearly zero-order. DTCC-Ca(II)-Tc showed very prolonged antimicrobial activity compared to that of free Tc.

• Fisheries and Aquatic Sciences
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• 제4권3호
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• pp.130-137
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• 2001

In the present study, the locomotor and feeding activities of single red sea bream, Pagrus major were simultaneously investigated to examine the existence of such dual behaviour. Seven red sea bream of 13cm body length on average were placed individually in 35L tanks equipped with an infrared sensor and a newly developed demand-feeding device. Fish were exposed to a light: dark 12: 12h cycle and constant darkness (DD) to study endogenous rhythmicity. Under LD 12: 12 h, the daily pattern of behaviour differed between individual fish; some red sea bream were diurnal and others were nocturnal. Futhermore, some of them displayed an extraordinary flexibility in phasing because they were dark active but light feeding, and vice versa. Under DD, red sea bream showed free-running rhythms for locomotor activity and feeding. These results indicate that the type of phasing of locomotor activity did not necessarily decide the feeding phase; much of this is explained by the fact that red sea bream were demand-fed. Flexibility in phasing and a certain degree of independence between locomotor and feeding activities could be seen as an adaptative response of the highly adaptable circadian rhythms of fish.

• Journal of Nutrition and Health
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• 제35권10호
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• pp.1031-1037
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• 2002

The purpose of present study was to evaluate the effect of endurance exercise training on skeletal muscle free amino acid concentrations, and differences in free amino acid concentration between soleus muscle which consists of mostly slow twitch oxidative fiber and extensor digitorum longus muscle which consists of fast twitch oxidative glycolytic fiber. Sixteen male SD rats (4 weeks old) were randomly devided into two groups, and fed a purified AIN-93M diet with or without aerobic exercise training according to the protocol (running on the treadmill at 25 m/min for 60 min, 5 days a week) for 6 weeks. Exercise-training for 6 weeks significanly reduced the commulative body weight gain (p＜0.05) and food efficiency ratio (p＜0.01) of rats. The result showing mitochondrial citrate synthase activity of soleus muscle was significantly higher in exercise-trained rats compared to the value for control animals (p＜0.01) indicates aerobic exercise-training was successfully accomplished in the trained group. No difference was found in the muscle aminogram pattern between soleus muscle and extensor digitorum longus muscle of control animals. However, free amino acid concentrations of soleus muscle were from 1.2 to 3.9 times of those found in extensor digitorum longus muscle of control rats, depending on an individual amino acid. Intermediate level of endurance exercise training for 6 weeks did not influence concentrations of most of free amino acid in soleus muscle of rats collected at an overnight fasted and rested state. In contrast, isolucine and leucine concentrations in extensor digitorum longus muscle of exercise-trained rats were significantly lower than those for control animals. These results indicate that aerobic energy metabolism had not been efficiently conducted, and thereby the utilization of BCAA for energy substrate was enhanced in fast twitch oxidative glycolytic fibers of extensor digitorum longus muscle of rats followed exercise-training protocol for 6 weeks.

• Physical Therapy Rehabilitation Science
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• 제2권1호
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• pp.12-20
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• 2013

Objective: To determine the energy consumed and muscle use during dance compared to different standard exercise devices. Design: Longitudinal study. Methods: Fifteen female subjects were evaluated to assess the energy cost and muscle activity during a 20 minute dance video compared to treadmill, elliptical track and bicycle ergometry. The later 3 forms of exercise were accomplished in four, 5 minute bouts at different intensities of exercise. Subjects were in the age range of 22-24 years old, were free of cardiovascular disease and did not have any neurological injuries. They were not sedentary and exercised at least twice a week. During the exercise, muscle activity was measured by the electromyogram recorded by surface electrodes on 6 muscle groups. A Cosmed metabolic cart was used to measure oxygen consumption during the exercise. Results: The aerobic dance video that was tested here was equivalent to a hard workout on any of the 3 exercise modalities. The dance routine was equivalent in terms of energy consumed to running at 225 watts of work or running for 20 minutes at a speed of 2 meters per second (4.47 miles per hour). Compared to the bicycle, it was equivalent to cycling at 112 watts for 20 minutes (2.25 kpm), and for the elliptical trainer, dance was equivalent to 435 watts. Concerning muscle use, the dance routine was the most balanced for upper, core and lower body muscles. Although the elliptical trainer was close, it required muscle less muscle use. Conclusion: A good dance video can be more effective than standard exercise equipment.

• 수면정신생리
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• 제5권1호
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• pp.1-11
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• 1998

Chronobiology is the area of medicine that is, how time-related event shape our daily biologic responses and apply to any aspect of medicine with regard to altering pathophysiology and treatment response. In mammals, there are several evidences that prove suprachiasmatic nuclei(SCN) is the major circadian pacemaker and the circadian rhythm influences so many biological aspects of an living organism such as rest-activity, thermoregulation, reproduction, and endocrine system. In case of human beings, there had been little information of circadian system. That may be due to the experimental, technical difficulties to study but also to the fact that human has the more complex environments that may alter the circadina rhythm like the artificial light, many socio-cultural aspects and so forth. However, several reports of these days indicate human's circadian system is composed of two or more circadian oscillators and SCN is the major circadian oscillator among them like the other mammals. Free-running circadinan period of mankind is about 24 hours rather than about 25 hours, and rest-activity rhythm is polymodal like other species. In addition to that, human may have capcities to change the circadian rhythm as the seasonal changes of daynight schedule. In this article, the author will summarize recent progress of anatomy and physiology of the circadian clock mechanism in humans.

• Journal of Nutrition and Health
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• 제35권7호
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• pp.729-736
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• 2002

The purpose of this study was to investigate the effects of glucuronic acid (isolated from xylan) on antioxidative defense system in rat after aerobic exercise. The glucuronic acid was isolated from xylan. Sprague-Dawley male rats weighing 150$\pm$10 g were randomly assigned to one normal group and three exercise training groups. Exercise training groups were classified to T (glucuronic acid free diet), TU (250 mg glucuronic acid/kg bw) and 2TU (500 mg glucuronic acid/kg bw) according to the level of glucuronic acid supplementation before exercise training. The experimental rats in exercise training groups (T, TU and 2TU) were exercised on glucuronic acid supplementation or rats in normal group (N) were confined in cage for 4 weeks. And rats were sacrificed with an overdose of pentobarbital injection just after running. Body weight, food intakes and food efficiency ratio (FER) were lower in the exercise training group than in the normal group. White gastrocnemius xanthine oxidase (XOD) activity in the T group was 85% greater than that of the normal group, whereas in the TU and 2TU groups it did not differ from the normal group. White gastrocnemius superoxide dismutase (SOD) activity in T group, that was decreased by 22% compared with that of N group, but those of TU and 2TU groups were increased by 38% and 42%, respectively, compared with that of T group. White gastrocnemius glutathione peroxidase (GSHpx) activity in T group, that was decreased by 42% compared with that of N group, but those of TU and 2TU groups were increased by 67% and 68%, respectively, compared with that of T group. Glutathione S-transferase (GST) activity of white gastrocnemius in N group was not significantly different from that in the T and TU groups, but 2TU group were increased by 12%. Contents of thiobarbituric acid reactive substance (TBARS) in T group was increased by 54%, compared with that of normal group but those of TU group and 2TU group were lower 44% and 36% than that of T group. In conclusion, the effects of glucuronic acids in exercise training rats would appear to reduce peroxidation of tissue as an antioxidative defense mechanism.