• The Journal of Korean Physical Therapy
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• v.14 no.4
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• pp.323-330
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• 2002

This study purposes at applying knee joint taping to preventing muscle fatigue. Twenty six subjects between the ages of 20s and 30s were randomly sampled among healthy males, with an average age of 26yr(range, 22 to 31yr). None of the subjects had a recent or remote history of significant lower extremity injury, No subjects had a history of central nervous system equilibrium problems. To develop muscle fatigue, Isokinetic exercise, which is a repetition of flexion and extension knee joint to $180^{\circ}$/sec, was performed 50 times per person. During the exercise, change of proprioception were measured by applying taping on both knee joints. Analysis has carried out by means of one-way ANOVA with repeated measures and independent t-test at the significance level of $\alpha$=0.05 to detect statistic significance. The results of this study were as follows: First, it was found that the generation of lower extremity muscle fatigue significant affects on proprioception (p < 0.05). Second, the application of taping to knee joint after the generation of lower extremity muscle fatigue significant affect proprioception (p < 0.05). Third, while continual exercise after the generation of muscle fatigue, taping group was significant differences in proprioceptive loss than non-taping group(p < 0.05).

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.10
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• pp.1227-1234
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• 2012

In this study, fatigue tests were carried out using real-scale pipe bend specimens with wall-thinning defects under a cyclic bending load together with a constant internal pressure of 10 MPa. The wall-thinning defect was located at the extrados and the intrados of the pipe bend specimens. A fully reversed cyclic in-plane bending displacement was applied to the specimens. For the pipe bends with wall thinning at the extrados, an axial crack occurred at the crown of the pipe bend rather than at the extrados where the defect was located. In addition, the fatigue life was longer than that of a sound pipe bend predicted from the design fatigue curve in ASME Sec.III, and it was less dependent on the axial length of the wall-thinning defect. For the pipe bends with wall thinning at the intrados, a circumferential crack occurred at the intrados. In this case, the fatigue life was much shorter than that of a sound pipe bend predicted from the design fatigue curve, and it clearly decreased with decreasing axial length of the wall-thinning defect.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.4
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• pp.670-679
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• 1989

The constant amplitude loading and 100% single overloading fatigue studies of domestic high tensile 7075-T73 aluminum alloy were performed to exmine the effect of specimen thickness and its mechanisms on fatigue crack growth behavior. The stage II fatigue crack growth rates tend to increase with decreasing specimen thickness under constant amplitude loading condition and this has relation with stress intensity factors and plastic zone size. The amount of retardation by an overload increased with decreasing specimen thickness when the crack depth and baseline stress intensity factors were constant. The crack depth is one of major factors which affect retardation phenomena by an overload and the amount of retardation increase with decreasing the crack depth. Its main mechanisms are crack closure and decreasing of K at the crack tip by branching and deflection of crack. And they are affected by near surface more severely than central portion of specimen.

• Environmental Analysis Health and Toxicology
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• v.27
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• pp.7.1-7.7
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• 2012

Objectives: Modafinil is a waking drug prescribed to narcolepsy patients, but its usage among healthy individuals is increasing to enhance their alertness or to mitigate fatigue. This study was conducted to investigate practical use and toxic effects on neuro-immune interaction of modafinil. Methods: This study reviewed the significance of psychoactive drugs, and discussed the benefits and risks of the application of modafinil, which seems to be ideal as an anti-psychotic or anti-fatigue agent. Results: Modafinil is known to have less or no adverse effects than those found in traditional psychostimulants such as amphetamine, methylphenidate or cocaine. It can be applied as an anti-psychotic or anti-fatigue agent. However, the waking mechanism of modafinil is yet to be fully revealed. Recent studies reported that modafinil may be subject to abuse and addiction. In addition prolonged sleeplessness induces stress responses and impairs immune function. Conclusions: Modafinil can be used by anyone, who wishes to work late, stay awake, enhance their cognitive reactions, or brighten their moods. Users may already be under a great level of stress, i.e. cancer patients or soldiers in a battle field. A psychoneuroimmunological approach is thus needed to investigate the multi-functional effects of modafinil.

• Journal of Biomedical Engineering Research
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• v.15 no.4
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• pp.429-438
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• 1994

An electrical stimulator was designed to induce locomotion for paraplegic patients caused by central nervous system injury. Optimal stimulus parameters, which can minimize muscle fatigue and can achieve effective muscle contraction were determined in slow and fast muscles in Sprague-Dawley rats. Stimulus patterns of our stimulator were designed to simulate eleclromyographic activity monitored during locomotion of normal subjects. Muscle types of the lower extremity were classified according to their mechanical property of contraction, which are slow muscle (msoleus m.) and fast muscle (medial gastrocnemius m., rectus femoris m., vastus lateralis m.). Optimal parameters of electrical stimulation for slow muscles were 20 Hz, 0.2 ms square pulse. For fast muscle, 40 Hz, 0.3 ms square pulse was optimal to produce repeated contraction. Higher'stimulus intensity was required when synergistic muscles were stimulated simultaneously than when they were stimulated individually. Electrical stimulation for each muscle was designed to generate bipedal locomotion, so that individual muscles alternate contraction and relaxation to simulate stance and swing phases. Portable electrical stimulator with 16 channels built in microprocessor was constructed and applied to paraplegic patients due to lumbar cord injury. The electrical slimulator restored partially gait function in paraplegic patients.

• Korean Journal of Applied Biomechanics
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• v.15 no.3
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• pp.51-59
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• 2005

To examine the influence of aging on the mechanism of muscle fatigue, we compared the magnitude of central and peripheral fatigue in young and old women before, during and after a sustained submaximaI isometric contraction of elbow flexor muscles. Twelve women (6 young. $20.7{\pm}1.2$ years and 6 old, $68.8{\pm}29$ years) performed a contraction at 20% of maximal voluntary contraction (MVC) torque with their non-dominant arm. The old women were weaker than the young women, however their endurance time for the 20% contraction was longer compared with the young women ($1822{\pm}444$ vs. $1061{\pm}678$ sec, P <. 05). Both groups had a similar reduction in voluntary activation ratio (VA) during and after the fatiguing contraction. However, the old women showed much greater variability in VA before and after the contraction ($91.61{\pm}4.54%$ and $76.70{\pm}19.55\;%$ range of $79{\sim}99$ to $87{\sim}99%$ respectively) compared with the young women ($95.71{\pm}1.86\;%$ and $83.46{\pm}7.57\;%$ range of $39{\sim}75$ to $69{\sim}90%$, respectively). Furthermore, the EMG activity of the elbow flexor muscles and triceps brachii was greater for the old women compared with the young women throughout the fatiguing contraction, indicating different activation strategies with age. Indices of peripheral fatigue including twitch properties, showed that fatigue within the muscle was more rapid for the young women compared with the old women. These results suggest that although old women are weaker than young women, they have greater endurance due to mechanisms within muscle. Furthermore, old women showed great variability in their ability to optimally activate all muscle fiber compared with young women for an isometric contraction.

• Journal of Physiology & Pathology in Korean Medicine
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• v.34 no.3
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• pp.117-125
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• 2020

The purpose of this review is to confirm whether Soyo-san (Xiaoyao-san) and its modifications is effective on alleviating clinical symptoms in chronic fatigue syndrome (CFS) patients. We collected clinical trials (randomized controlled trial, quasi-randomized controlled trial, controlled clinical trial) to investigate the effects of Soyo-san and its modifications on general symptoms, fatigue, depression and anxiety in CFS patients. The databases used for data retrieval were Pubmed, Central Cochrane, Embase, CNKI, CQVIP, Wanfang, CiNii, OASIS, RISS, and Koreamed. We performed selection/exclusion process from the found studies to conform with prespecified criteria, and assessed the final included trials according to the Cochrane risk of bias tool. The included studies were classified based on the interventions in experimental and control group. Eight randomized controlled trials and one controlled clinical trial (total 921 participants) were eligible and their results were synthesized in the meta analysis. The synthesis showed a considerable effect of Soyo-san and its modifications on improvement of general symptoms (relative risk 0.27 [95% CI 0.19 to 0.39], Z=7.03, P<0.00001; I2=0%) and fatigue severity (SMD -1.20 [95% CI -1.46 to -0.93], Z=8.78, P<0.00001; I2=52%) in CFS patients, while Effect on depression and anxiety were inconclusive. We found that Soyo-san and its modifications were effective for improvement of general symptoms and fatigue severity in CFS post-treatment.

• International Journal of Aeronautical and Space Sciences
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• v.11 no.4
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• pp.285-302
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• 2010

Active aeroelastic control is an emerging technology aimed at providing solutions to structural systems that under the action of aerodynamic loads are prone to instability and catastrophic failures, and to oscillations that can yield structural failure by fatigue. The purpose of the aeroelastic control among others is to alleviate and even suppress the vibrations appearing in the flight vehicle subcritical flight regimes, to expand its flight envelope by increasing the flutter speed, and to enhance the post-flutter behavior usually characterized by the presence of limit cycle oscillations. Recently adaptive and robust control strategies have demonstrated their superiority to classical feedback strategies. This review paper discusses the latest development on the topic by the authors. First, the available control techniques with focus on adaptive control schemes are reviewed, then the attention is focused on the advanced single-input and multi-input multi-output adaptive feedback control strategies developed for lifting surfaces operating at subsonic and supersonic flight speeds. A number of concepts involving various adaptive control methodologies, as well as results obtained with such controls are presented. Emphasis is placed on theoretical and numerical results obtained with the various control strategies.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.1
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• pp.11-16
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• 2014

The effects of environment and microstructure on low cycle fatigue (LCF) behaviors of CF8M stainless steels containing 11% of ferrites were investigated in a $310^{\circ}C$ deoxygenated water environment. The reduction of LCF life of CF8M in a $310^{\circ}C$ deoxygenated water was smaller than 316LN stainless steels. Based on the microstructure and fatigue surface analyses, it was confirmed that the hydrogen induced cracking contributed to the reduction in LCF life for CF8M as well as for 316LN. However, many secondary cracks were found on the boundaries of ferrite phases in CF8M, which effectively reduced the stress concentration at the crack tip. Because of the reduced stress concentration, the accelerated fatigue crack growth by hydrogen induced cracking was less significant, which resulted in the smaller environmental effects for CF8M than 316LN in a $310^{\circ}C$ deoxygenated water.

• Herbal Formula Science
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• v.28 no.2
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• pp.199-209
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• 2020

Objectives : The purpose of this systematic review is to confirm whether Gwibitang is beneficial in chronic fatigue syndrome (CFS). Methods : Clinical trials were searched from databases including Pubmed, Embase, Central Cochrane, CNKI, Wanfang, CQVIP, CiNii, OASIS, Koreamed, and NDSL. The eligible study design was limited into randomized controlled trial, quasi-randomized controlled trial and controlled clinical trial. The outcomes included general effectiveness as nominal scale, and fatigue severity, insomnia severity and quality of life as interval or ratio scale. The meta-analysis and assessment of risk of bias was performed based on the data extracted from the selected trials. Results : The results of eight randomized controlled trials (n=596) were included in the meta-analysis. The results of the synthesis showed Gwibitang is beneficial substantially for relieving and managing the general symptoms, and its heterogeneity was not in important level (RR 0.26 [95% CI 0.17, 0.39], Z=6.47, P<0.00001, I²=0%). Gwibitang was beneficial for alleviating fatigue (SMD -0.78 [95% CI -1.27, -0.30], Z=3.17, P=0.002), but its certainty was low. In case of insomnia, too few trials had been found and their risk of bias was substantial, so no conclusions had been brought to. Conclusions : We found an evidence that Gwibitang could be beneficial for managing and alleviating main symptoms in CFS patients.