• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.185-186
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• 2002

Fretting of fuel rod cladding material, Zircaloy-4 tube, in PWR nuclear power plants must be reduced and avoided. Nowadays the introduction of surface treatments or coatings is expected to be an ideal solution to fretting damage since fretting is closely related to wear. corrosion and fatigue. Therefore. in this study the fretting wear experiment was performed using TiAlN coated Zircaloy-4 tube as the fuel rod cladding and uncoated Zircaloy-4 as on of grids, especially concentrating on the sliding component. Fretting wear resistance of TiAlN coated Zircaloy-4 tubes was improved compared with that of TiN coated tubes and uncoated tubes and fretting wear mechanisms were brittle fracture and plastic flow at lower slip amplitude but severe oxidation and spallation of oxidative layer at higher ship amplitude.

• Biomolecules & Therapeutics
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• 제21권2호
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• pp.89-96
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• 2013

Atherosclerotic vascular dysfunction is a chronic inflammatory process that spreads from the fatty streak and foam cells through lesion progression. Therefore, its early diagnosis and prevention is unfeasible. Reactive oxygen species (ROS) play important roles in the pathogenesis of atherosclerotic vascular disease. Intracellular redox status is tightly regulated by oxidant and antioxidant systems. Imbalance in these systems causes oxidative or reductive stress which triggers cellular damage or aberrant signaling, and leads to dysregulation. Paradoxically, large clinical trials have shown that non-specific ROS scavenging by antioxidant vitamins is ineffective or sometimes harmful. ROS production can be locally regulated by cellular antioxidant enzymes, such as superoxide dismutases, catalase, glutathione peroxidases and peroxiredoxins. Therapeutic approach targeting these antioxidant enzymes might prove beneficial for prevention of ROS-related atherosclerotic vascular disease. Conversely, the development of specific antioxidant enzyme-mimetics could contribute to the clinical effectiveness.

• Bulletin of the Korean Chemical Society
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• 제27권5호
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• pp.663-666
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• 2006

Carnosine, homocarnosine and anserine might act as anti-oxidants and free radical scavengers in vivo. In the present study, the protective effects of carnosine and related compounds on the $H_2O_2$-mediated cytochrome c modification were studied. Carnosine, homocarnosine and anserine significantly inhibited the oligomerization of cytchrome c induced by $H_2O_2$. All three compounds also inhibited the formation of carbonyl compound and dityrosine during the incubation of cytochrome c with $H_2O_2$. These compounds effectively inhibited the peroxidase activity in the cytchrome c treated with $H_2O_2$. The results suggested that carnosine, homocarnosine, and anserine might protect cytochrome c against $H_2O_2$-mediated oxidative damage through a free radical scavenging.

• 약학회지
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• 제50권1호
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• pp.58-63
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• 2006

The antioxidant enzyme (AOE) system plays an important role in the defense against oxidative stress damage. To determine whether myricetin or myricetin/taurine can exert antioxidative effects not only by modulating the AOE system directly but also by scavenging free radical, we investigated the influence of the myricetin and taurine on cell viability ROS level, activities of different antioxidant enzyme, and the expression of different antioxidant enzyme. As results, the cell viability showed inhibition of the proliferation with treatment of 'myricetin' or 'myricetin with taruine', respectively, with dose-dependent manner. Compared to control, the treatment of 'myricetin' decreased activities and gene expressions of superoxide dismutase (SOD), and glutathione peroxidase (GPx). However, combined treatment of 'myricetin with taurine' increased activities and gene expressions of the SOD, GPx, and catalase (CAT). In addition, the combined treatment of 'myricetin with taurine' somewhat decreased ROS levels, compared to the treatment of 'myricetin'. In conclusion, our study provides that the combined treatment of different antioxidants can enhance antioxidant effects.

• 한국잠사학회:학술대회논문집
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• 한국잠사학회 2003년도 International Symposium of Silkworm/Insect Biotechnology and Annual Meeting of Korea Society of Sericultural Science
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• pp.112-113
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• 2003

Kynurenic acid (KYNA), tryptophan metabolite is known to have cell protective effect against various insults in the brain. But so far, the protective mechanism is largely unknown. In this study, we investigated how the KYNA exerts protective effect against 6-OHDA, a causative molecule of Parkinsonian syndrome, using SH-SY5Y cells. (omitted)

• 대한예방의학회:학술대회논문집
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• 대한예방의학회 2005년도 제57차 추계 학술대회 연제집
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• pp.406-406
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• 2005

• 대한예방의학회:학술대회논문집
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• 대한예방의학회 2005년도 제57차 추계 학술대회 연제집
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• pp.432-432
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• 2005

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 제35회 춘계학술대회
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• pp.88-95
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• 2002

Fretting of fuel rod cladding material, Zircaloy-4 Tube, in PWR nuclear power plants must be reduced and avoided. Nowadays the introduction of surface treatments or coatings is expected to bean ideal solution to fretting damage since fretting is closely related to wear, corrosion and fatigue. Therefore, in this study the fretting wear experiment was peformed using TiAIN coated Zircaloy-4 tube as the fuel rod cladding and uncoated Zircaioy-4 tube as one of grids, especially concentrating on the sliding component. Fretting wear resistance of TiAIN coated Zircaloy-4 tubes was improved compared with that of TiN coated tubes and uncoated tubes and the fretting wear mechanisms were delamination and plastic flow following by brittle fracture at lower slip amplitude but severe oxidation and spallation of oxidative layer at higher slip amplitude.

• BMB Reports
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• 제32권5호
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• pp.440-444
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• 1999

Membrane lipid peroxidation processes yield reactive aldehydes that may react with copper,zinc superoxide dismutase (Cu,Zn SOD), one of the key antioxidant enzymes against oxidative stress. We investigated this possibility and found that exposing Cu,Zn SOD to malondialdehyde (MDA) or 4-hydroxynonenal (HNE) caused the loss of dismutase activity, cross-linking of peptides, and an increase in protein oxidation, reflected by the increased level of carbonyl groups. When Cu,Zn SOD that had been exposed to MDA or HNE was subsequently analyzed by amino acid analysis, histidine content was found to be significantly lost. Both MDA-and HNE-treated Cu,Zn SOD were resistant to proteolysis, which may imply that damaged proteins exist in vivo for a longer period of time than the native enzyme. The lipid peroxidation-mediated damage to Cu,Zn SOD may result in the perturbation of cellular antioxidant defense mechanisms, and subsequently lead to a pro-oxidant condition.

• 한국독성학회:학술대회논문집
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• 한국독성학회 2001년도 International Symposium on Signal transduction in Toxicology
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• pp.146-146
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• 2001

Gastroesophageal reflux disease (GERD) is multifactorial in etiology and is characterized by movement of acid and other noxious substances from the stomach into the esophagus. The most severe histologic consequence of chronic gastroesophgeal reflux is Barrett's esophagus, which has been considered as a premalignant condition often leading to the formation of adenocarcinoma of esophagus.(omitted)