• Proceedings of the PSK Conference
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• 2003.04a
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• pp.212.2-212.2
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• 2003

Primary cultured rat hepatocytes injured by carbon tetrachloride as a model to screen for hepatoprotective effect. Four flavonoid compounds showed anti-hepatotoxic effect by decrease GPT. LDH activity and MDA level. Also screen for hepatoprotective, anti-oxidative and anti-apoptosis effects of baicalin and baicalein on chang cell treated with t-BHP. Mesured radical detoxifying enzyme, GST and antioxidant enzyme SOD, Catalase activity, GSH level and Cellular glutathion peroxidase activity. (omitted)

• Journal of Environmental Science International
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• v.24 no.11
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• pp.1315-1329
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• 2015

The objective of this study was to investigate anticytotoxic and antioxidatative capacities of ethanol extracts from Acer tegmentosum Maxim (A. tegmentosum) stem in vitro. The extract at concentration of 200 ug/mL inhibited 10 and 20 ug/mL arsenic trioxide-induced cytotoxicity of HepG2 cells by 79.3 and 57.5%, respectively. The extract at concentration of 200 ug/mL inhibited 0.2 and 0.5 mM t-BHP-induced cytotoxicity of HepG2 cells by 66.3 and 35.7%, respectively. Antioxidative effects of the extract were examined via measurement of ABTS, superoxide, and peroxyl radical scavenging activities. ABTS radical scavenging activity of the extract was higher than that of ${\alpha}$-tocopherol. Superoxide scavenging activity of the extract was higher than that of catechin. Oxygen radical absorbance capacity of the extract was higher than that of ascorbic acid. Cupric reducing antioxidant capacity of the extract was higher than that of ${\alpha}$-tocopherol. The extract at concentrations of 100 and $500{\mu}g/mL$ inhibited 10 mM t-BHP-induced lipid peroxidation of HepG2 cells by 38.2 and 80.7%, respectively. The extract prevented supercoiled DNA strand breakage induced by hydroxyl or peroxyl radical. Total phenolic and flavonoid contents of the extract at concentration of $100{\mu}g/mL$ were 71.3 nmol/mL gallic acid and 18.8 nmol/mL catechin equivalents, respectively. Thus, strong cytoprotective and antioxidant effects of A. tegmentosum stem extract seem to be due to, at least in part, the prevention from free radicals-induced oxidation as well as high levels in polyphenolic contents.

• The Journal of Internal Korean Medicine
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• v.23 no.1
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• pp.57-64
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• 2002

Objective : This study was designed to investigate the anti-oxidative effects of Oldenlandiae Diffusae Herba Water extract (ODHW) on lipid peroxidation by free radicals oxidative hepatic injury. Methods : In order to evaluate anti-oxidative activities of ODHW in the liver cell, cultured normal rat liver cells(Ac2F) were incubated with or without ODHW. After 16 hours to 18 hours of experiment, cells were placed in DMEM medium without serum, and then incubated with 1mM tert-butyl hydro-peroxide(t-BHP) for two hours. Viable cells were detected by MTT assay. The levels of LPO induced by hydroxyl radical derived from H2O2-Fe2+ system in rat liver homogenate were determined by means of TBA. Inhibitory effect of ODHW on superoxide generation was measured by xanthine-xanthine oxidase system. Results : In the linoleic acid autoxidation system, ODHW exhibited antioxidant activity, which inhibited 85% of linoleic acid peroxidation. These effects were similar to those of dl-a-tocopherol. ODHW showed scavenging effects on DPPH radical, inhibited superoxide generation in xanthine-xanthine oxidase system, and also inhibited lipid peroxidation of rat liver tissue with hydroxyl radical derived from $H_2O_2-Fe^{2+}$ system. In addition, ODHW protected the cell death induced by t-BHP and it significantly increased cell viability in a normal rat liver cell(Ac2F)

• The Korean Journal of Food And Nutrition
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• v.34 no.5
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• pp.423-429
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• 2021

Barley's nutritional value as a health food is increasing due to its excellent nutritional functionality. In this study, the levels of β-glucan, total polyphenols, and total flavonoids were analyzed in the ethanol extracts of different barley cultivars (Hinchalssal, Heuksoojeongchal, Betaone, Ganghochung, and Saechalssal). Also, the free radical scavenging abilities of 2,2-diphenyl-1-picryl-hydrazil (DPPH) and 2,2'-azino-bis-3-ethylbenzo-thiaxoline-6-sulfonic acid (ABTS) were measured to determine their antioxidant activity. The results confirmed that Betaone extract contained highly activefunctional components and exhibitedantioxidant activity. Next, we evaluated the hepatoprotective and inhibitory effects of reactive oxygen species (ROS) generated by barley ethanol extracts after inducing oxidative stress with tert-butyl hydroperoxide (tBHP) in HepG2 cells. Hinchalssal and Saechalssal extracts showed the most significant cytoprotective effect and also reduced ROS production significantly. These results suggest that Hinchalssal, Saechalssal, and Betaone represent potential natural antioxidant and hepatoprotective agents.

• Journal of Life Science
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• v.15 no.1 s.68
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• pp.106-111
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• 2005

To investigate the antioxidant activity of extract from the raw walnut, Juglans sinensis Dode, we prepared five fractions (methanol (MeOH), dichloromethane $(CH_2Cl_2)$, ethyl acetate (EtOAc), n-buthanol (n-BuOH) and dehydrogen monooxide $(H_2O)$ fractions) and examined. The effect of walnut extract on the oxidative stress was investigated in vitro. The DPPH (2,2-Di (4-tert-octylphenyl)-1-picrylhydrazyl) free radical scavenging activity of extract from raw walnut was shown in the following order: $EtOAc\;fraction layer. The result showed that the highest activity $(0.56{\mu}g/ml,\;IC_{50}.)$ was observed in EtOAc fraction, whereas n-BuOH fraction, MeOH fraction, $CH_2O_2$ fraction and $H_2O$ layer of $IC_{50}$ were $2.34{\mu}g//ml,\;3.88{\mu}g/ml,\;8.06{\mu}g/ml,\;and\;8.19{\mu}g/ml$, respectively. The radical scavenging activity assay of each fraction showed that the antioxidative activity was observed in the following order: EtOAc fraction $(74.27\pm1.56\%)>MeOH\;fraction\;(60.76\pm3.4\%)>n-BuOH\;fraction\;(59.32\pm0.88\%)>H_2O\;layer\;(41.69\pm2.06\%)$. These results revealed that all fractions, except for $CH_2Cl_2$ fraction, showed high antioxidative activity. Furthermore, the peroxynitrite $(ONOO^-)$ scavenging activity was assayed in each fraction. The result showed that the $ONOO^-$ scavenging activity of EtOAc fraction, MeOH fraction and n-BuOH fraction from raw walnut was $95.14\pm0.36\%,\; 90.02\pm1.19\%\;and\;89.41\pm0.81\%$, respectively. The tert-butylhydroperoxide (t-BHP) treatment in vitro increased lactate dehydrogenase release and lipid peroxidation in renal cortical slices. Such changes were completely prevented by addition of MeOH fraction, EtOAc fraction and n-BuOH fraction of walnut. These results indicate that the walnut extract exerts the benedicial effect against t-BHP-induced cell injury and its effect may be due to antioxidant action. In addition, it is suggested that walnut extract might be developed as the effective scavenger for the prevention of oxidative stress.

• Archives of Pharmacal Research
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• v.20 no.5
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• pp.496-500
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• 1997

A strong antioxidant activity, which was measured by the radical scavenging effect on 1, 1-diphenyl-2-picrylhydrazyl(DPPH) radical, was detected in the methanol extract of Salvia miltiorrhiza Bunge (Labiatae). By activity-directed fractionation, compounds 1 and 2 were isolated as antioxidant principles of S. miltiorrhiza. Compounds 1 and 2 were identified as dimethyl lithospermate and 3-(3, 4-dihydroxyphenyl)lactamide, respectively, on the basis of spectral data. The radical scavenging effect of compounds 1 and 2 on DPPH radical exceeded that of L-ascorbic acid which is a well known antioxidant. These two compounds also showed prominent inhibitory activity against free radical generation in dichlorofluorescein (DCF) method and cytoprotective effect against t-BHP in cultured liver cell.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.11 no.1
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• pp.21-25
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• 1975

Authors studied the propulsion efficiency of G. T. 280 to 300 class tuna longliners used in Korea. At first authors calculated the ratios and factors of the ship by use of principal dimensions. In cordance with this ratios and factors authors, examined the effective horse power, propulsion ficiency and brake horse power, and following results are obtained. (1) EHP is slightly increased according to the increasing of Froude number and speed. (2) Value of propulsion coefficient is obtained in the range of 51-54% at the cruising speed an its average is 52% in 6-13 knot of the speed. (3) EHP and BHP are increased according to the increasing of prismatic coefficient at the same speed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.845-848
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• 2002

The wrinkling in the flange and wall of a part is a predominent failure mode in stamping of sheet metal parts. In many cases this wrinkling may be eliminated by appropriate control of the blank holding forco(BHF), but BHF affects the draw depth. Gotoh had studied the wrinkles under 0.02mm in height. In general, the height of wrinkles could be limited under 0.2mm practically. Therefore small BHP can be allowed so that the depth of drawing could be increased. Authors research the variation of the wrinkles in flange in the course of cup drawing by using aluminium alloy Al050 and A5052.

• Transactions of Materials Processing
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• v.22 no.4
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• pp.223-228
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• 2013

The friction coefficients of advanced high strength steel sheets were experimentally determined. In the friction test, the pulling and holding forces acting on the sheet for various friction conditions, such as lubricant viscosity, pulling speed, blank holding pressure, sheet surface roughness, and hardness of the sheet were measured and the friction coefficient was calculated based on Coulomb's friction law. While the friction coefficient, generally, decreases as the value of friction factor increases, the factor associated with the sheet surface roughness shows U shape behavior for the friction coefficient. Furthermore, the relationship between friction coefficient and the wear volume, which was computed for the roughness of both sheet surfaces and the friction area, is linearly proportional.

• Special Issue of the Society of Naval Architects of Korea
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• 2015.09a
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• pp.41-45
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• 2015

In this study reviewed the validity of the estimated optimum trim by the numerical analysis. For this purpose, the numerical analysis of the trim optimization for 6500TEU container carrier and capesize bulk carrier were carried out using Star-CCM+, which results were compared with the results of model tests. The reliability of results of the numerical analysis was confirmed via comparing the resistance determined by the numerical analysis and model test. The performance of self-propulsion at each trim conditions were estimated using the calculated resistance by numerical analysis. The BHP at each trim condition were calculated by estimated performance of self-propulsion, which trend of results were confirmed similar trend of result of model test.