• Steel and Composite Structures
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• v.50 no.3
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• pp.363-374
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• 2024

The fatigue life of steel wire is affected not only by fatigue load, but also by corrosion environment in service period. Specially, the corrosion pit will lead to stress concentration on the surface of steel wire inducing the formation of fatigue cracks, and the fatigue cracks will accelerate the corrosion process. Therefore, the corrosion fatigue of steel wire is a coupling effect. In this study, the corrosion-fatigue coupling life curve is derived with considering corrosion-fatigue pitting stage, corrosion-fatigue short crack stage and corrosion-fatigue long crack stage. In addition, the stress concentration factors of different corrosion pits are calculated by COMSOL software. Furthermore, the effect of corrosion environment factors, that is, corrosion rate, corrosion pit morphology, frequency and action factor of fatigue load, on fatigue life of steel wire is analyzed. And then, the corrosion-fatigue coupling life curve is compared with the fatigue life curve and fatigue life curve with pre-corrosion. The result showed that the anti-fatigue performance of the steel wire with considering corrosion-fatigue coupling is 68.08% and 41.79% lower than fatigue life curve and fatigue life curve with pre-corrosion. Therefore, the corrosion-fatigue coupling effect should be considered in the design of steel wire.

• International Journal of Industrial Entomology and Biomaterials
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• v.39 no.1
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• pp.34-38
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• 2019

In this study, we investigated the effect of silkworm, and its by-products on exercise endurance, muscle mass, and fatigue recovery using ICR mice model. Powders of silkworm, pupae, dongchunghacho, and silk powder were suspended in water and feed to mice for 2 weeks. The forced swimming time was increased by 4.3, 4.1 and 2.8 seconds after silkworm, pupae, and dongchughacho administration compared to DW fed group. Increases in exercise ability were achieved by difference mechanism according to feeding materials. Pupae increased muscle mass by 129% compared with the control group which may effect on elongation of swimming time. Dongchunghacho improved the plasma concentrations of fatigue markers such as creatinine, blood urea nitrogen (BUN), and D-lactate. Silkworm administration showed dual effect, the muscle mass induction (114% vs. control) and anti-fatigue (plasma creatinine, BUN, and D-lactate were 63, 75, and 78% vs. con) effect which contributed most elongated swimming time. In conclusion, silkworm and its by-products including pupae and dongchunghacho with the predominant protein and bioactive components improved muscle mass and showed anti-fatigue effect which could promote exercise performance ability.

• Korean Journal of Pharmacognosy
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• v.44 no.1
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• pp.83-90
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• 2013

The aim of this study was to evaluate the effect of hot water extract of peduncle obtained from Hovenia dulcis Thunb (HD) which is commercially developed for the protective effect on the alcoholic hepatotoxicity, on the endurance capacity for weight loaded forced swimming mice. The swimming times to exhaustion in mice fed 100 and 200 mg/kg HD for 2 weeks were prolonged 3.6 and 3.7 fold, and for 4 weeks 1.9 and 2.7 fold compared with each vehicle control ($42.8{\pm}20.5$ min and $67.7{\pm}47.8$ min, for 2 and 4 weeks), respectively. Blood biochemical parameters for ALT, AST, creatinine and BUN were not significantly different between from HD fed or control mice. Although HD fed mice swam over 2 fold longer time than vehicle control mice at 4 weeks, blood biomarkers of physical fatigue such as glucose, triglyceride and free fatty acid, lactate were not significant different and even tended to ameliorate. Hepatic lipid peroxidation and SOD activity did not significantly change in HD fed- and vehicle control exhausted swimming mice at 2 or 4 weeks. However, catalase activity in HD-fed mice was significantly increased in a dose-dependent manner compared with vehicle control mice. The present study indicates that HD improved physical fatigue and exercise performance in mice. Therefore, it has a potential for the pharmacological effect of anti-fatigue.

• Korean Journal of Pharmacognosy
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• v.43 no.1
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• pp.54-58
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• 2012

To increase the extraction yield and biological effect of antler by fermentation, probiotics fermenting antler were screened from rice shells. Of screened Bacillus species, the most potently antler-degrading probiotics was Bacillus KH-07. The supernatant yield of fermented antler is highest. Bacillus KH-07 may belong to Bacillus licheniformis by biochemical and 16S rDNA sequencing analyses. The KH-07-fermented antler (50 mg/kg) increased the anti-fatigue effect 2.3-fold compared to that of non-treated antler. Furthermore, the KH-07-fermented antler improved $CCl_4$-induced liver injury in mice. Based on these findings, the extraction yield and biological effect of antler can be increased by KH-07 fermentation.

• Korean Journal of Oriental Medicine
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• v.14 no.3
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• pp.41-47
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• 2008

Objective : The purpose of this report was to provide the information about activity and safety of Ssanghwa-tang by analyzing domestic papers and theses about Ssanghwa-tang. Methods : Domestic papers and theses related to Ssanghwa-tang were reviewed and analyzed. These papers were then classified by year, experimental method, and activity subject. Results : The following result s were obtained in this study. 1. The study of Ssanghwa-tang started from 1981 and continued steadily 1990s and it was decreased 2000s. 2. The paper of Ssanghwatang was entire domestic paper, 20 volumes. 3. In classified by experimental method and animal of Ssanghwa-tang paper, more than a half study used rat in vivo experiment. Furthermore clinical experiments were performed about anti-fatigue effect of Ssanghwa-tang and Ssanghwatang was proved a safety herbal medicine in acute toxicity experiment. 4. Decursin, glycyrrhizin, paeoniflorin were determined in Ssanghwa-tang by using HPLC analysis. 5. As these studies were classified by subject, papers related to anti-fatigue effect were most abundant by 7 papers. Besides there were several papers related to liver funtion, anti-inflammatory, alleviation, smooth muscle relaxation effect and so on. 6. According to experimental data, it is supported that Ssanghwa-tang was safety herbal medicine and it has a several activity about anti-fatigue, anti-inflammatory, alleviation, smooth muscle relaxation. Conclusion : Many study of basic science experiments and clinical experiments were performed and reported on Ssanghwa-tang in domestic journal. Ssanghwa-tang is being used in various ways associating with anti-fatigue, anti-inflammatory, alleviation and smooth muscle relaxation. furthermore Ssanghwatang was proved a safety herbal medicine in acute toxicity experiment. However, studies on randomized controlled trials of Ssanghwatang need to be completed at the clinical level.

• Journal of Applied Biological Chemistry
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• v.63 no.1
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• pp.69-74
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• 2020

The fruit, leaves, and roots of Elaeagnus multiflora Thunb. have been used in traditional Chinese medicine to treat cough, diarrhea, and itching. However, the anti-fatigue effects of E. multiflora fruit (EMF) extract have not been studied in detail. The aim of this study was to examine the effect of EMF on fatigue and exercise performance in BALB/c mice. EMF was orally administered to mice at four doses (10, 50, 100, and 200 mg/kg/day) for 2 weeks. The anti-fatigue activity was evaluated by determining the exhaustive swimming time. Blood lactate and glucose levels and serum lactate levels after a 10 min swimming time, as well as ammonia, creatine kinase (CK), blood urea nitrogen (BUN), lactate dehydrogenase (LDH), and glycogen contents after exhaustive swimming time were measured. The exhaustive swimming time of the EMF 200 group was significantly increased (p <0.01). The EMF groups showed significantly low levels of CK, BUN, LDH, and lactate compared with the control group (p <0.05). Increased liver glycogen was observed in the EMF 200 group (p <0.05). These results suggest that EMF can be utilized as an efficacious natural resource for its anti-fatigue effects.

• The Journal of Korean Obstetrics and Gynecology
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• v.21 no.1
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• pp.28-38
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• 2008

Purpose: This study was conducted to investigate the muscular strength & stamina improvement and muscle anti-fatigue effects of Morinda officinalis How after long term administration. Methods: 4-6 weeks old ICR mice were used in this study and we administered the water soluble extracts of Morinda officinalis How in the concentration of 1, 10. 100/mg/0.3ml to each 5 mice (ATS group) and same volume of normal saline was administered to 5 mice (control group) once a day for 90 or 120 days. After the administration we performed the swimming exercise test and the grip strength test. And we measured the concentration of glucose and the activity of lactate dehydrogenase in plasma regarded as biochemical indicator related with the muscular fatigue. Results: In swimming exercise test, all ATS groups showed increased time compared with relative control group after 90 days administration. After 120 days adminstration 100/mg/0.3ml ATS groups showed increased results. In grip strength test, all ATS groups showed increased grip strength compared with relative control group after 90 days administration. After 120 days adminstration 10/mg/0.3ml ATS groups showed increased result. All the results of plasma glucose didn't showed statistically significant difference after 90 and 120 days administration. In the plasma concentration of activity level of lactate dehydrogenase, all ATS groups didn't showed statistically significant difference compared after 90 days administration. Conclusion: This study show that Morinda officinalis How can increase the muscular strength & stamina and anti-fatigue effect.

• The Journal of Korean Medicine
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• v.37 no.2
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• pp.76-84
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• 2016

Objectives: We evaluated the anti-fatigue effects of Rh2-enriched Korean ginseng (Ginseng Rh2+) using a forced exercise-induced chronic fatigue mouse model. Methods: ICR male mice were subjected to running wheel for 1 h, 5 days/week during 4 weeks, and running velocity was gradually increased. Each running session was followed by oral administration of distilled water, Ginseng Rh2+ (150 or 300 mg/kg), or N-acetyl-L-cysteine (NAC, 100 mg/kg) 1 h later. The exercise tolerance and forced swimming test were performed to evaluate the fatigue condition. Results: Chronic forced exercise reduced the physical activity, as evidenced by the behavioral tests, which were notably ameliorated by Ginseng Rh2+ treatment. Ginseng Rh2+ treatment also attenuated the alterations of energy metabolism and oxidative stress in skeletal muscle tissues and/or sera, including malondialdehyde (MDA), lactate concentration and its related factors (lactate dehydrogenase, blood urea nitrogen, and glucose levels). Conclusion: These findings strongly suggest that Ginseng Rh2+ exerts a potent anti-fatigue effect through modulation of energy metabolism and oxidative response.

• YAKHAK HOEJI
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• v.44 no.3
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• pp.224-231
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• 2000

$Nokyangbotang^{TM}$ (NYBT) is a kind of powerful food for health and have been drunk at a oral dose of 80 ml (99.5 mg) three times per day: It has not been well studied about the anti-fatigue and hepatoprotective activity. In this experiments, we evaluated pathophysiologically the effect of NYBT on swimming time in mouse and hepatoprotective activity in rats intoxicated with carbon-tetrachloride. NYBT was nontoxic in orally acute toxicity test ($LD_{50}$, 320 ml/60 kg): a nontoxic food in more four times of one-shoot dosage (80 ml) to human. Weight-loaded forced swimming test was carried out to measure the swimming time of mice with a 4% load of body weight in plastic cylinder (diameter $10{\;}cm{\;}{\times}{\;}height{\;}20{\;}cm$) on water bath at $25^{\circ}C$, and the anti-fatigue activity represented the ratio of swimming time of experimental group to that of control group. NYBT had dose-dependent anti-fatigue activity Mice administered NYBT at a dose of 320 ml/60 kg once daily for 5 days could swim about two times more than control. Hepatoprotective activities of NYBT were examined by the determination of malonedialdehyde (MDA) and pathological survey in liver and liver function test of rat intoxicated with $CCl_4$ at i.m. dose of 2 ml/kg once daily for 7days. NYBT decreased dose-dependently thiobarbituric acid reactive substance: Oral administration of NYBT at a dose of 20 ml/60 kg was $38.51{\;}{\pm}{\;}3.02$ nmol MDA/g of tissue, that of 80 ml/60 kg was $33.76{\;}{\pm}{\;} 1.84$ nmol MDA/g of tissue, and that of 320 ml/60 kg was $32.87{\;}{\pm}{\;}1.90$ nmol MDA/g of tissue as compared with control group ($43.61{\;}{\pm}{\;}2.85$ nmol MDA/g of tissue). All rats administered NYBT at a dose of 320 ml/60 kg were survival as compared with 40% survival of control animals, and GPT activity of rats administered NYBT at a dose of 80 ml/60 kg was decreased as compared with control. In histopathological survey, NYBT improved slightly the fatty changes of hepatocytes around centrilobular area. These results suggest that NYBT has anti-fatigue and hepatoprotective activity in rats and mice.

• Journal of the Korean Society for Heat Treatment
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• v.29 no.6
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• pp.277-283
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• 2016

The influences of cooling pressure of quenching process on the mechanical properties such as hardness, impact endurance and anti-thermal fatigue behaviour of STD61 steel were investigated. The specimens were heat-treated using a vacuum furnace in which they were austenitized at $1,030^{\circ}C$ for 1hour under the pressure of $10^{-3}$ torr and cooled with quenching gas of various pressure, i.e. 1, 2 and 6 bar. According to the observation on the specimens prepared with quenching from austenizing temperature, the mechanical properties of the samples with higher quenching pressure were better than those of prepared at lower quenching pressure. The samples prepared with high quenching pressure showed the more homogeneous microstructure with finer carbides. The size of carbides such as VC and (Fe, Cr)C in quenched specimens decreased with increasing gas quenching pressure. It is considered that the rapid cooling with pressure may restrict the formation and growth of carbide.