• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.6
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• pp.1382-1387
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• 1994

A model is constructed to evaluate the stress intensity factors for a center crack subjected to anti-symmetric loading in a layered material. A Fredholm integral equation is derived using the Fourier integral transform method. The integral equation is numerically analyzed to evaluate the effects of stress intensity factor on the shear modulus, Poisson's ratio and crack length to layer thickness. In case of the isotropic homogeneous material, the values of stress intensity factor derived in the present study agree with the previous solutions.

• Korean Journal of Environmental Biology
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• v.31 no.4
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• pp.376-382
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• 2013

[6]-Gingerol, a major polyphenol of ginger (Zingiber officinale), exhibits a variety of biological properties including anti-oxidant, anti-inflammatory and anti-cancer activity. However, the radioprotective effect of [6]-gingerol is still unknown. The aim of this study was to investigate the radioprotective effect of [6]-gingerol against radiation-induced cell cytotoxicity and oxidative stress in HepG2 cells. [6]-Gingerol pretreatment attenuated radiation-induced cell cytotoxicity caused by 5Gy (half lethal dose, $LD_{50}$ of HepG2 cells). The measurements of superoxide dismutase (SOD) and catalase (CAT) activity were also performed. The results showed that [6]-gingerol pretreatment reduced increasing SOD and CAT activity after exposure of IR, indicating that [6]-gingerol protected oxidative stress by regulating cellular antioxidant enzyme (SOD and CAT) activity. These findings suggest that [6]-gingerol acts as a radioprotector by attenuating cell cytotoxicity and oxidative stress.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2022.09a
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• pp.119-119
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• 2022

The coronavirus disease 2019 (COVID-19) pandemic may be stressful for people. Public health actions, such as social distancing, can make people feel isolated and lonely and can increase stress and anxiety. As a result, there is a growing interest towards various materials to relieve stress. Thus, the present study aimed to investigate the anti-stress effects of ethanol extract of Ziziphus jujuba in PC12 cells treated with corticosterone and its underling mechanisms. Furthermore, the viability of the cells, the apoptosis of the cells, the level of phosphorylation of extracellular signal-regulated kinases (p-ERKs) expression were measured by MTT assay, LDH assay, Hoechst staining assay and western blotting. Our results showed that the extract of Ziziphus jujuba reversed corticosterone-induced damage in PC12 cells, which increased cell viability, decreased LDH release, and attenuated corticosterone-induced apoptosis as compared with the corticosterone-treated group. Therefore, these data suggest that the extract of Ziziphus jujuba could be a good candidate for development as a functional food supplement in the improve the anti-stress effect.

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.5
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• pp.441-446
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• 2013

In the present study, the anti-depressant like effect of methyl gallate (MG) isolated from the stem bark of Acer barbinerve was examined in ICR mice. Body weight (BDW) and blood glucose (BDG) levels significantly decreased in the repeated restraint stress (RRS) group (2 h/day for 14 days) compared to the no stress (NS) group. To examine the effect of MG on RS-induced BDW loss and hypoglycemia, MG (10 mg/kg) and the anti-depressant fluoxetine (10 mg/kg) were administered daily for 14 days. Orally administered MG and fluoxetine significantly attenuated the RS-induced BDW loss and hypoglycemia. Interestingly, MG administered mice showed increased BDG levels in the normal and glucose feeding condition. Chronic RS-subjected mice showed immobilized and depressed behaviors. The effect of MG on the depressed behaviors was evaluated using the tail-suspension test (TST) and the forced swimming test (FST). In both tests, RS-induced immobilized behaviors were significantly reversed in MG and fluoxetine administered groups. Taken together, MG significantly attenuated the RS-induced BDW loss, hypoglycemia, and depressed behaviors. Considering that decreased BDG levels (hypoglycemia) can cause depression, MG may exert its anti-depressant like effect by preventing hypoglycemia. Our results suggest that MG isolated from A. barbinerve can exert anti-depressant like effect, and could be used as a new and natural anti-depressant therapy.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.4
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• pp.874-883
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• 2007

The aqueous extract of Chungsimyeonja-eum has been used to treat palpitation, anemia, chronic fatigue, hypertension, and stroke. It also possesses various pharmacological effects including hypotensive, blood circulating, sedative, anti-inflammatory, diuretic, and anti-stress activities. In the present results, the latency time of plantar test was decreased in the immobilization stress and incusion pain-induction group. However the paw withdrawal latency values were increased in the immobilization stress and incision pain-induction groups after treatment with the aqueous extract of Chungsimyeonja-eum. The c-Fos expression in the paraventricular nucleus (PVN), and 5-hydroxytryptamine (5-HT) and tryptophan hydroxylase (TPH) in the dorsal raphe were enhanced in the immobilization stress and incision pain-induction groups. However, the treatment with the aqueous extract of Chungsimyeonja-eum suppressed the immobilization stress and incision pain-induced increase of c-Fos, 5-HT, and TPH expressions. Here in this study, we have demonstrated the protective effects of Chungsimyeonja-eum on immobilization and incision pain-induced stress. The present study revealed that Chungsimyeonja-eum treatment diminishes immobilization and pain stress.

• Nutrition Research and Practice
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• v.9 no.2
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• pp.117-122
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• 2015

BACKGROUND/OBJECTIVES: Curcumin, a major component of the Curcuma species, contains antioxidant and anti-inflammatory properties. Although it was found to induce apoptosis in cancer cells, the functional role of curcumin as well as its molecular mechanism in anti-inflammatory response, particularly in intestinal cells, has been less investigated. The intestine epithelial barrier is the first barrier and the most important location for the substrate coming from the lumen of the gut. SUBJECTS/METHODS: We administered curcumin treatment in the human intestinal epithelial cell lines, T84 and Caco-2. We examined endoplasmic reticulum (ER) stress response by thapsigargin, qPCR of XBP1 and BiP, electrophysiology by wild-type cholera toxin in the cells. RESULTS: In this study, we showed that curcumin treatment reduces ER stress and thereby decreases inflammatory response in human intestinal epithelial cells. In addition, curcumin confers protection without damaging the membrane tight junction or actin skeleton change in intestine epithelial cells. Therefore, curcumin treatment protects the gut from bacterial invasion via reduction of ER stress and anti-inflammatory response in intestinal epithelial cells. CONCLUSIONS: Taken together, our data demonstrate the important role of curcumin in protecting the intestine by modulating ER stress and inflammatory response post intoxication.

• The Journal of Internal Korean Medicine
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• v.25 no.1
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• pp.1-15
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• 2004

Objective : This study was aimed to evaluate the anti-starvation stress effect of Liriopis Tuber on mice. Method : The first experiment was done to mice which have a high corticosterone level at a short term starvation. The plasma corticosterone level of each mouse was measured over time at 12, 24, 36, 48, 72 hours of starvation respectively. The second experiment was done in the two groups(LT A and LT B) of mice which were in famine for 36.5 hours after being administered Liriopis Tuber three times with different doses(LT A: 1.0 g/.kg and LT B: 3.0g/kg) for three days. The plasma corticosterone levels and rectal temperature were measured when a 36.5-hour of starvation period was finished. Results : 1. The corticosterone level in the mice was significantly increased after a 36.5-hour of starvation. (P<0.001). 2. The plasma corticosterone level was decreased significantly in the group of 3.0g/kg, compared to the control group.(P<0.05) 3. The rectal temperature in the groups of 1.0g/kg and 3.0g/kg were increased slightly in both group. But the two groups didn't show significant change. Conclusion: Based on the above results, Liriopis Tuber might have anti-starvation stress effect and it may be used as anti-starvation stress medicine and anti-stress medicine. Conclusion : Based on the above results, Liriopis Tuber might have anti-starvation stress effect and it may be used as anti-starvation stress medicine and anti-stress medicine.

• Korean Journal of Agricultural Science
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• v.46 no.3
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• pp.427-437
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• 2019

Oxidative stress and overproduction of free radicals have been reported to be a major pathological hallmark of neurodegenerative diseases. Samultang has been known as a beneficial agent to treat liver disease and cardiovascular diseases. However, the anti-oxidant activities and neuro-protective effects of Samultang against oxidative stress still have not been evaluated yet. The aim of the present study was to investigate the anti-oxidant and protective effects of Samultang and its four herbal plants, Paeonia lactiflora (PL), Ligusticum striatum (LS), Rehmannia glutinosa (RG), and Angelica gigas (AG), in vitro system and in SH-SY5Y neuronal cells. The extracts of Samultang strongly increased the radical scavenging activities of 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl radical (${\cdot}OH$), and nitric oxide (NO) in a concentration-dependent manner. Furthermore, we investigated the protective effects of Samultang on cellular damage against oxidative stress induced by hydrogen peroxide ($H_2O_2$) in SH-SY5Y cells. Treatment with Samultang alleviated the oxidative stress from $H_2O_2$ by increasing the cell viability and decreasing the intracellular reactive oxygen species levels. Based on these results, we further investigated the radical scavenging effects of PL, LS, RG, and AG. In our results, PL had the highest DPPH, ${\cdot}OH$, and NO radical scavenging activities. Thus, PL has a crucial role in Samultang, which has anti-oxidative and neuro-protective effects. The present research suggests that Samultang and PL have protective roles against oxidative stress from $H_2O_2$-induced neuronal cell death.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.2 s.173
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• pp.496-505
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• 2000

A semi-infinite parallel crack propagated with constant velocity in two bonded anisotropic strip under anti-plane clamped displacement is analyzed. Using Fourier integral transform a Wiener-Hopf equation is derived. By solving this equation the asymptotic stress and displacement fields near the crack tip are determined, where the results give the more general expression applicable to the extent of the anisotropic material having one plane of elastic symmetry for the parallel crack. The dynamic stress intensity factor and energy release rate are also obtained as a closed form, which are the results applicable to the problem both of dynamic and static crack under the same geometry as this study. The stress intensity factor approaches zero at the critical crack velocity which is less than the shear wave velocity, but in typical case of isotropic or orthotropic material agrees with the velocity of shear wave. Also a circular shear stress around crack tip is considered, from which the stress is shown to be approximately symmetric about the horizontal axis. Referring to the maximum stress criteria, it could be shown that a brenched crack is formed by crack growth as crack velocity increases.

• The Korea Journal of Herbology
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• v.28 no.4
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• pp.57-62
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• 2013

Objectives : Lonicerae Japonicae Flos (LJF) has been shown anti-oxidant, anti-inflammatory, anti-viral, anti-rheumatoid properties. However, it is still largely unknown whether LJF inhibits skin injury against oxidative stress in human keratinocyte, HaCaT cells. The purpose of this study was to evaluate the protective effects of LJF against hydrogen peroxide($H_2O_2$)-induced oxidative stress in human keratinocytes, HaCaT cells. Methods : To evaluate out the protective effects of LJF on oxidative injury in HaCaT cells, an oxidative stress model of HaCaT cells was established under a suitable concentration (500 ${\mu}M$) hydrogen peroxide. HaCaT keratinocyte cells were pre-treated with LJF (0.1, 0.25 or 0.5 mg/ml), and then stimulated with $H_2O_2$. Then, the cells were harvested to measure the cell viability, DNA damage, and release of reactive oxygen species (ROS). Results : LJF (0.1, 0.25 or 0.5 mg/ml) itself did not show any significant toxicity in HaCaT cells. The treatment of $H_2O_2$ caused the oxidative stress, leading to the cell death, and DNA injury. However, pretreatment with LJF reduced cell death, and DNA injury. The stimulation of $H_2O_2$ on HaCaT cells resulted in excessive release of ROS, which is the main factor of oxidative stress. The excessive release of ROS was inhibited by LJF treatment significantly. Conclusions : These results could suggest that LJF exhibited the protective effects of HaCaT cells against $H_2O_2$-induced oxidative stress by inhibiting ROS release. It could be explained that LJF inhibit skin damages against oxidative stress. Thus, LJF would be useful for the development of drug or cosmetics treating skin troubles.