• The Korean Journal of Ecology
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• v.26 no.3
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• pp.115-121
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• 2003

Leaves of two-week old seedlings of tomato (Lycopersicon esculentum) were treated with various concentrations (0∼100 M) of $CdCl_2$ for up to 9 days and subsequent growth of seedlings, symptoms of oxidative stress and isozyme activities of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and peroxidase (POX) were investigated. Compared with the non-treated control, Cd exposure decreased biomass but increased Cd accumulation, hydrogen peroxide production and lipid peroxidation as malondialdehyde (MDA) formation in leaves and roots. Further studies on the developmental changes of isozyme activities showed that Fe-SOD, Cu/Zn-SOD and one of three APX isozymes decreased and CAT and one of four POX isozymes increased in leaves, whereas Fe-SOD, one of three POX isozymes and two of four APX isozymes decreased and CAT increased in roots, showing different expression of isozymes in leaves and roots with Cd exposure level and time. Based on our results, we suggest that the reduction of seedling growth by Cd exposure is the oxidative stress resulting from the over production of $H_2O_2$ and the insufficient activities of antioxidant enzymes particularly involved in the scavenging of $H_2O_2$. Further, the decreased activities of SOD and APX isozymes of chloroplast origin, the increased activities of CAT and POX and high $H_2O_2$ contents with Cd exposure might indicate that Cd-induced oxidative stress starts outside chloroplast.

• Journal of Oriental Neuropsychiatry
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• v.8 no.2
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• pp.51-62
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• 1997

This experiment was done to investigate the antioxidant effect of Ondamtang(ODT) on brain tissues of rats. The experimental groups were divided into three groups and treated as follows for a fifteen days ; Negative control group(NC), Vitamin E admistrated group(PC), ODT administrated Group(ODT). After the extracting microsome from brain of rats, those were measured the amounts of Malondiadehyde and Hydrogen peroxide, then activities of antioxidant enzymes like Superoxide dismutase, Catalase and NADPH-cytochrome P-450 reductadse. The results were as follows; 1. In TBA reaction to measure the amount of MDA, oxidant material of brain tissue of rats, the group treated by ODT showed significant decrease. 2. In the formation of Hydrogen peroxide, the group treated by ODT showed no change in comparison with normal group. 3. The activity of SOD in the group treated by ODT showed a little increase in comparison with normal group. 4. The activity of Catalase was increased significantly in the group treated by ODT than normal group. 5. The activity of NADPH-cytochrome P-450 reductase in the group treated by ODT showed a little increase in comparison with normal group. According to the above results, it is suggested that Ondamtang(ODT) has some antioxidant effects on tissues of brain.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.2
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• pp.57-64
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• 2008

In general, the entire of paper mulberry bark, which is not cut into pieces with an appropriate length, have been used in the pulping. This kind of pulping method couldn't accomplish the improvement of beating and sheet forming efficiency. For this reason, we investigated the effects of the cutting length of paper mulberry bast fiber on pulping and Hanji (Korean traditional paper) properties, in order to develop high quality Hanji manufacturing process. The cutting length variation of paper mulberry white bast did not great effects on pulp yields. The pulp yields based on pulping methods were sulfomethylated pulping av. 57.4%, alkali-hydrogen peroxide pulping av. 55.4%, and alkaline pulping av. 53.5% respectively. The optical properties such as brightness, opacity, scattering coefficient, and absorption coefficient were slightly improved by the increase of paper mulberry white bast cutting length. The increase of paper mulberry white bast cutting length resulted in poor sheet formation. Physical properties such as breaking length, TEA, tear index, burst index, and folding endurance were slightly improved by the increase of cutting length. The modified pulping processes, which used sulfomethylated method and alkali-hydrogen peroxide method, showed better pulp and sheet properties than conventional alkaline pulping.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.1
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• pp.165-170
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• 2007

Pyungwi-san(PWS) have been using as a basic prescription of digestive disorder in Korean traditional medicine. This study was performed to examine the in vitro antioxidant activity of the extract using different antioxidant tests including by 1,1-diphenyl-2-picryl-hydrazil (DPPH) radical scavenging, superoxide anion radical scavenging, metal chelating hydrogen peroxide scavenging, lipid peroxydation protective effect and scavenging effect of nitric oxide and peroxynitrite. Herbal-acupuncture solution of PWS(PWS-HS) exhibited a concentration-dependent inhibition of DPPH radical adduct formation and it showed dose-dependent free radical scavenging activity onto superoxide anions. In addition, the result of metal chelating hydrogen peroxide scavenging and ammonium thiocyanate experiments showed that PWS-HS was an active scavenger of hydroxyl radicals. Furthermore, it was also found to be effective in scavenging nitric oxide and peroxynitrite, well-known cytotoxic species that can oxidize several cellular components such as proteins, lipids and DNA.

• Biomolecules & Therapeutics
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• v.17 no.4
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• pp.395-402
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• 2009

Insulin appears to play a role in brain physiology, and disturbances of cerebral insulin signalling and glucose homeostasis are implicated in brain pathology. The objective of the present study was to investigate the protective effects of insulin under conditions of oxidative stress induced by hydrogen peroxide ($H_2O_2$) in C6 glial cells. Insulin at concentration of $10^{-7}$ M could prevent 12 h $H_2O_2$-induced cell death. The formation of reactive oxygen species (ROS), nitric oxide (NO) and 2-thiobarbituric acid-reactive substances (TBARS) were significantly scavenged by insulin pre-treatment in C6 glial cells after $H_2O_2$-induced oxidative stress. Insulin significantly stimulated the phosphorylation of Akt in the cells and the activation of Akt was maintained in response to insulin under $H_2O_2$ incubation for 12 h. In conclusion, these results provide evidence that insulin acts as a free radical scavenger and stimulating Akt activity. These data suggest that insulin may be effective in degenerative diseases with oxidative stress.

• Biomolecules & Therapeutics
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• v.13 no.3
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• pp.150-155
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• 2005

The ethanolic extract of chestnut (Castanea crenata S. et Z., Fagaceae) inner shell (CISE) and one of its components, ellagic acid (EA), were evaluated for their protective effects against 1, 1-diphenyl-2-picryl hydrazine (DPPH) free radical generation and hydrogen peroxide-induced oxidative DNA damage in a mammalian cell line. CISE and EA were shown to possess the free radical scavenging effect against DPPH radical generation, significantly. They were also found to strongly inhibit hydrogen peroxide-induced DNA damage from Chinese hamster lung (CHL) cell, assessed by single cell gel electrophoresis assay and 8-hydroxy -2'-deoxy guanosine (8-OH-2'dG) assay. Furthermore, topical application of CISE [$12.5\%$(w/w) cream] and ellagic acid [$1.0\%$(w/w) cream] for 14 days potently inhibited malondialdehyde (MDA) formation of mouse dorsal skin (a marker of lipid peroxidation) induced by ultraviolet B exposure. Therefore, CISE and its component, ellagic acid, may be the useful natural antioxidants by scavenging free radicals, inhibition of lipid peroxidation and protecting oxidative DNA damage when topically applied.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.1
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• pp.74-79
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• 2007

Most studies on copper Chemical Mechanical Planarization (CMP) have focused on material removal and its mechanisms. Although many studies have been conducted on the mechanism of Cu CMP, a study on uniformity in Cu CMP is still unknown. Since the aim of CMP is global and local planarization, the approach to various factors related to uniformity in Cu CMP is essential to elucidate the Cu CMP mechanism as well. The main purpose of the experiment reported here was to investigate and mechanically analyze the roles of slurry components in the formation of the uniformity in Cu CMP. In this paper, Cu CMP was performed using citric acid($C_{6}H_{8}O_{7}$), hydrogen peroxide($H_{2}O_{2}$), colloidal silica, and benzotriazole($BTA,\;C_{6}H_{4}N_{3}H$) as a complexing agent, an oxidizer, an abrasive, and a corrosion inhibitor, respectively. All the results of this study showed that within-wafer non-uniformity(WIWNU) of Cu CMP could be controlled by the contents of slurry components.

• Food Science of Animal Resources
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• v.18 no.2
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• pp.97-106
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• 1998

Antioxidant enzymes such as catalase (CAT), glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) are known to inhibit oxidative reactions by incativating compounds responsible for the formation of ree radicals. SOD transforms superoxide radical into hydrogen peroxide which is precursor to active free radicals. CAT reduces hydrogen peroxide to water. GSH-Px reduces hydroperoxides to corresponding alcohols. Antioxidant enzyme activities of muscle are different by animal species age, stress and exercise, muscle type and part, conditions of post mortem, storage and processing which are related to oxidative deterioration I muscle foods as well as oxidative defence in living systems. Antioxidant enzyme systems are enhanced rather than weakened in aging skeletal muscle. Red muscle contains higher antioxidant enzyme activity than white muscle. The antioxidant enzyme activities of poultry are higher in leg than in breast, and those of beef are higher in redder and more unstable muscles. It is clear that the effectiveness of the antioxidant enzyme in muscle foods seems to be influenced by meat processing operations. Both GSH-Px and CAT are inactivated by heat processing NaCl also influence the efficiency of the antioxident enzymes since its presence diminishes their catalyitc activity.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.3
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• pp.957-963
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• 2016

Cellular senescence, a barrier to tumorigenesis, controls aberrant proliferation of cells. We here aimed to investigate cellular senescence in immortalized cholangiocyte and cholangiocarcinoma cell lines using five different inducing agents: 5-aza-2'deoxycytidine, bromodeoxyuridine, interferons ($IFN{\beta}$ and $IFN{\gamma}$), and hydrogen peroxide. We analyzed senescence characteristics, colony formation ability, expression of genes involved in cell cycling and interferon signaling pathways, and protein levels. Treatment with all five agents decreased cell proliferation and induced cellular senescence in immortalized cholangiocyte and cholangiocarcinoma cell lines with different degrees of growth-inhibitory effects depending on cell type and origin. Bromodeoxyuridine gave the strongest stimulus to inhibit growth and induce senescence in most cell lines tested. Expression of p21 and interferon related genes was upregulated in most conditions. The fact that bromodeoxyuridine had the strongest effects on growth inhibition and senescence induction implies that senescence in cholangiocarcinoma cells is likely controlled by DNA damage response pathways relating to the p53/p21 signaling. In addition, interferon signaling pathways may partly regulate this mechanism in cholangiocarcinoma cells.

• Bulletin of the Korean Chemical Society
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• v.25 no.2
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• pp.249-252
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• 2004

Cytochrome P450 (P450)/$O_2$/NADPH engender electron transfer reaction of N-benzyl-N-substituted benzylamines to yield corresponding radical cation 1 that is simultaneously converted into 2 and 3. Subsequently, expulsion of proton and hydroxylation yielding a-hydroxylamines are followed by formation of benzaldehydes and benzylamines.