• BMB Reports
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• v.45 no.5
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• pp.317-322
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• 2012

2-deoxy-D-glucose(2DG)-caused endoplasmic reticulum (ER) stress inhibits protein phosphorylation at tyrosine residues. However, the accurate regulatory mechanisms, which determine the inflammatory response of chondrocytes to ER stress via protein tyrosine phosphorylation, have not been systematically evaluated. Thus, in this study, we examined whether protein phosphorylation at tyrosine residues can modulate the expression and glycosylation of COX-2, which is reduced by 2DG-induced ER stress. We observed that protein tyrosine phosphatase (PTP) inhibitors, sodium orthovanadate (SOV), and phenylarsine oxide (PAO) significantly decreased expression of ER stress inducible proteins, glucose-regulated protein 94 (GRP94), and CCAAT/ enhancer-binding-protein- related gene (GADD153), which was induced by 2DG. In addition, we demonstrated that SOV and PAO noticeably restored the expression and glycosylation of COX-2 after treatment with 2DG. These results suggest that protein phosphorylation of tyrosine residues plays an important role in the regulation of expression and glycosylation during 2DG-induced ER stress in rabbit articular chondrocytes.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.10a
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• pp.359-365
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• 2002

The fatigue crack growth behavior of the SA516/60 steel which is used for pressure vessels was examined experimentally at room temperature $25^{\circ}C,\;-30^{\circ}C,\;-60^{\circ}C,\;-80^{\circ}C,\;-100^{\circ}C$ and $-120^{\circ}C$ with stress ratio of R=0.05, 0.1 and 0.3. Fatigue crack propagation rate da/dN related with stress intensity factor range ${\Delta}K$ was influenced by stress ratio in stable of fatigue crack growth (Region II) with an increase in ${\Delta}K$. The resistance of fatigue crack growth at low temperature is higher compared with that at room temperature, which is attributed to tile extent of plasticity-induced by compressive residual stress according to the cyclic loads. Fractographic examinations reveal that the differences of the fatigue crack growth characteristics between room and low temperatures are mainly explained by the crack closure and the strengthening due to the plasticity induced and roughness induced.

• The Korean Journal of Physiology and Pharmacology
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• v.27 no.1
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• pp.105-112
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• 2023

Oxidative stress in skin cells can induce the formation of reactive oxygen species (ROS), which are critical for pathogenic processes such as immunosuppression, inflammation, and skin aging. In this study, we confirmed improvements from gamma-irradiated silk sericin (I-sericin) and gamma-irradiated silk fibroin (I-fibroin) to skin cells damaged by oxidative stress. We found that I-sericin and I-fibroin effectively attenuated oxidative stress-induced ROS generation and decreased oxidative stress-induced inflammatory factors COX-2, iNOS, tumor necrosis factor-α, and interleukin-1β compared to the use of non-irradiated sericin or fibroin. I-sericin and Ifibroin effects were balanced by competition with skin regenerative protein factors reacting to oxidative stress. Taken together, our results indicated that, compared to non-irradiated sericin or fibroin, I-sericin, and I-fibroin had anti-oxidation and antiinflammation activity and protective effects against skin cell damage from oxidative stress. Therefore, gamma-irradiation may be useful in the development of cosmetics to maintain skin health.

• Nutrition Research and Practice
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• v.8 no.5
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• pp.494-500
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• 2014

BACKGROUND/OBJECTIVES: This study investigated whether Padina arborescens extract (PAE) protects INS-1 pancreatic ${\beta}$ cells against glucotoxicity-induced apoptosis. MATERIALS/METHODS: Assays, including cell viability, lipid peroxidation, generation of intracellular ROS, NO production, antioxidant enzyme activity and insulin secretion, were conducted. The expressions of Bax, Bcl-2, and caspase-3 proteins in INS-1 cells were evaluated by western blot analysis, and apoptosis/necrosis induced by high glucose was determined by analysis of FITC-Annexin V/PI staining. RESULTS: Treatment with high concentrations of glucose induced INS-1 cell death, but PAE at concentrations of 25, 50 or $100{\mu}g/ml$ significantly increased cell viability. The treatment with PAE dose dependently reduced the lipid peroxidation and increased the activities of antioxidant enzymes reduced by 30 mM glucose, while intracellular ROS levels increased under conditions of 30 mM glucose. PAE treatment improved the secretory responsiveness following stimulation with glucose. The results also demonstrated that glucotoxicity-induced apoptosis is associated with modulation of the Bax/Bcl-2 ratio. When INS-1 cells were stained with Annexin V/PI, we found that PAE reduced apoptosis by glucotoxicity. CONCLUSIONS: In conclusion, the present study indicates that PAE protects against high glucose-induced apoptosis in pancreatic ${\beta}$ cells by reducing oxidative stress.

• Biomolecules & Therapeutics
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• v.18 no.1
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• pp.24-31
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• 2010

Taurine, 2-aminoethanesulfonic acid, is an abundant free amino acid present in brain cells and exerts many important biological functions such as anti-convulsant, modulation of neuronal excitability, regulation of learning and memory, anti-aggressiveness and anti-alcoholic effects. In the present study, we investigated to explore whether taurine has any protective actions against oxidative stress-induced damages in neuronal cells. ERK I/II regulates signaling pathways involved in nitric oxide (NO) and reactive oxygen species (ROS) production and plays a role in the regulation of cell growth, and apoptosis. We have found that taurine significantly inhibited AMPA induced cortical depolarization in the Grease Gap assays using rat cortical slices. Taurine also inhibited AMPA-induced neuronal cell damage in MTT assays in the differentiated SH-SY5Y cells. When the neuronal cells were treated with $H_2O_2$, levels of NO were increased; however, taurine pretreatment decreased the NO production induced by $H_2O_2$ to approximately normal levels. Interestingly, taurine treatment stimulated ERK I/II activity in the presence of AMPA or $H_2O_2$, suggesting the potential role of ERK I/II in the neuroprotection of taurine. Taken together, taurine has significant neuroprotective actions against AMPA or $H_2O_2$ induced damages in neuronal cells, possibly via activation of ERK I/II.

• Preventive Nutrition and Food Science
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• v.19 no.3
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• pp.170-177
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• 2014

Endothelial cell dysfunction is considered to be a major cause of vascular complications in diabetes. In the present study, we investigated the protective effect of a baechu kimchi added Ecklonia cava extract (BKE) against high glucose induced oxidative damage in human umbilical vein endothelial cells (HUVECs). Treatment with a high concentration of glucose (30 mM) induced cytotoxicity, whereas treatment with BKE protected HUVECs from high glucose induced damage; by restoring cell viability. In addition, BKE reduced lipid peroxidation, intracellular reactive oxygen species and nitric oxide levels in a dose dependent manner. Treatment with high glucose concentrations also induced the overexpression of inducible nitric oxide synthase, cyclooxygenase-2 and NF-${\kappa}B$ proteins in HUVECs, but BKE treatment significantly reduced the overexpression of these proteins. These findings indicate that BKE may be a valuable treatment against high glucose-induced oxidative stress HUVECs.

• Journal of Magnetics
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• v.3 no.4
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• pp.112-115
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• 1998

Possible sources of the stress-anneal-induced anisotropy in FINEMET-type magnets are reviewed and discussed resulting in a conclusion that the most probable origin of this anisotropy is the atomic pair directional ordering. It is also evidence that the anisotropy considered is usually of an easy-plane type.

• Journal of Ginseng Research
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• v.37 no.3
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• pp.315-323
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• 2013

Ginseng is known to have antistress effects. Previously, red ginseng (RG) was shown to repress stress-induced peptidyl arginine deiminase type IV (PADI4) via estrogen receptor ${\beta}$ ($ER{\beta}$) in the brain, thus inhibiting brain cell apoptosis. Moreover, tumor necrosis factor (TNF)-${\alpha}$ plays a critical role in immobilization (IMO) stress. However, the signaling pathway of RG-mediated repressesion of inflammation is not completely understood. In this study, we determined how RG modulated gene expression in stressed brain cells. Since secretion of TNF-${\alpha}$ is modulated via TNF-${\alpha}$ converting enzyme (TACE) and nuclear factor (NF)-${\kappa}B$, we examined the inflammatory pathway in stressed brain cells. Immunohistochemistry revealed that TACE was induced by IMO stress, but RG repressed TACE induction. Moreover, PADI4 siRNA repressed TACE expression compared to the mock transfected control suggesting that PADI4 was required for TACE expression. A reporter assay also revealed that $H_2O_2$ oxidative stress induced NF-${\kappa}B$ in neuroblastoma SK-N-SH cells, however, RG pretreatment repressed NF-${\kappa}B$ induction. These findings were supported by significant induction of nitric oxide and reactive oxygen species (ROS) by oxidative stress, which could be repressed by RG administration. Taken together, RG appeared to repress stress-induced PADI4 via TACE and NF-${\kappa}B$ in brain cells thus preventing production of ROS and subsequently protecting brain cells from apoptosis.

• Geomechanics and Engineering
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• v.22 no.2
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• pp.133-142
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• 2020

The evolution of the mining-induced fracture network formed during longwall top coal caving (LTCC) has a great influence on the gas drainage, roof control, top coal recovery ratio and engineering safety of aquifers. To reveal the evolution of the mining-induced stress and fracture network formed during LTCC, the fracture network in front of the working face was observed by borehole video experiments. A discrete element model was established by the universal discrete element code (UDEC) to explore the local stress distribution. The regression relationship between the fractal dimension of the fracture network and mining stress was established. The results revealed the following: (1) The mining disturbance had the most severe impact on the borehole depth range between approximately 10 m and 25 m. (2) The distribution of fractures was related to the lithology and its integrity. The coal seam was mainly microfractures, which formed a complex fracture network. The hard rock stratum was mainly included longitudinal cracks and separated fissures. (3) Through a numerical simulation, the stress distribution in front of the mining face and the development of the fracturing of the overlying rock were obtained. There was a quadratic relationship between the fractal dimension of the fractures and the mining stress. The results obtained herein will provide a reference for engineering projects under similar geological conditions.

• Korean Journal of Pharmacognosy
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• v.39 no.4
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• pp.335-340
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• 2008

Diabetes mellitus is metabolic disorder characterized by hyperglycemia caused by insufficient insulin secretion or insulin receptor insensitivity to endogenous insulin. It is well-known that hyperglycemia is one of the main causes of oxidative stress in both type 1 and 2 diabetes. Oxidative stress is related by death of pancreatic ${\beta}$ cell and dysfunction of ${\beta}$ cell. Although ${\beta}$ cell death or dysfunction is induced by many substances or molecules, increased evidences that oxidative stress plays a crucial role in ${\beta}$ cell death or dysfunction. Considering the importance of oxidative stress in the pathogenesis of diabetes mellitus, we investigated the cytoprotective effects against hydrogen peroxide-induced oxidative stress in pancreatic ${\beta}$ cell line RIN-m5F cell. 110 Plant sources were collected in Mt. Baek-du, and extracted with methanol. These extracts had been screened the protective effects against hydrogen peroxide-induced oxidative damage in RIN-m5F cells at 50 and 200 ${\mu}g$/ml. Of these, ten methanolic extracts, aerial part of Erigenron cannadensis, aerial part of Lespedeza juncea, whole plant of Alopecurus aequalis, fruit of Lycium chinense, leaf of Morus alba, rhizome of Polygonatum odoratum, root of Ampelosis japonica, whole plant of Ranunculus japonicus, aerial part of Polygonum sieboldii, rhizome of Arisaema amurense var. violaceum showed significant protective effects against hydrogen peroxide-induced oxidative damage in pancreatic ${\beta}$ cell line RIN-m5F cell.