• BMB Reports
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• 제46권10호
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• pp.513-518
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• 2013

We investigated the protective effects of Gymnaster koraiensis against oxidative stress-induced hepatic cell damage. We used two different cytotoxicity models, i.e., the administration of tert-butyl hydroperoxide (t-BHP) and acetaminophen, in HepG2 cells to evaluate the protective effects of G. koraiensis. The ethyl acetate (EA) fraction of G. koraiensis and its major compound, 3,5-di-O-caffeoylquinic acid (DCQA), exerted protective effects in the t-BHP-induced liver cytotoxicity model. The EA fraction and DCQA ameliorated t-BHP-induced reductions in GSH levels and exhibited free radical scavenging activity. The EA fraction and DCQA also significantly reduced t-BHP-induced DNA damage in HepG2 cells. Furthermore, the hexane fraction of G. koraiensis and its major compound, gymnasterkoreayne B (GKB), exerted strong hepatoprotection in the acetaminophen-induced cytotoxicity model. CYP 3A4 enzyme activity was strongly inhibited by the extract, hexane fraction, and GKB. The hexane fraction and GKB ameliorated acetaminophen-induced reductions in GSH levels and protected against cell death.

• 한국환경독성학회:학술대회논문집
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• 한국환경독성학회 2002년도 추계국제학술대회
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• pp.169-169
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• 2002

The mobilizable amount of transition metals is a fraction of the total amount of the metal from urban particulate matter. Although the fraction is small, some metals (Fe, Cu) are the major participants in a reaction that generates reactive oxygen species (ROS), which can damage various biomolecules. Damaging effects of the metals can be measured by the single strand breakage (SSB) of X174 RFI DNA or the carbonyl formation of protein. In another study, we have shown that more metals are mobilized by PM2.5 than by PM10 in general. DNA SSB of >20% for PM2.5 and >15% for PM10 was observed in the presence of chelator (EDTA or citrate)/reductant (ascorbate), compared to the control (<3%) only with the chelator. The carbonyl formation by both PMs was very similar in the presence of the chelator, regardless of the kind of proteins. Compared to the control in the absence of chelator/reductant, 3.3 times and 4.9 times more carbonyl formation for PM2.5 and PM10, respectively, was obtained with BSA in the presence of chelator/reductant, showing that PM10 induced 33% more damage than PM2.5. However, 4.8 times and 1.9 times more carbonyl formation for PM2.5 and PM10, respectively, was observed with lysozyme in the presence of chelator/reductant, showing that PM2.5 induced 250% more damage than PM10. Although different proteins showed different sensitivities toward ROS, all these results indicate that the degrees of the oxidation of or damage to the biomolecules by the mobilized metals were higher with PM2.5 than with PM10. Therefore, it is expected that more metals mobilized from PM2.5 than from PM10, more damage to the biomolecules by PM2.5 than by PM10. We suggest that when the toxicity of the dust particle is considered, the particle size as well as the mobilizable fraction of the metal should be considered in place of the total amounts.

• 농업과학연구
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• 제39권1호
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• pp.81-86
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• 2012

In this study, the antioxidative effect and protective potential against oxidative damage of extract and fractions from broccoli were investigated under in vitro and cellular system. The methanol (MeOH) extracts of broccoli flowers and sprouts were partitioned as dichloromethane, n-butanol (BuOH) and aqueous fractions. The comparison of antioxidative effect of broccoli flowers and sprouts showed that broccoli sprouts exerted the more effective protective activity from 2,2'-azobis (2-aminopropane) dihydrochloride (AAPH)-induced oxidative stress in LLC-$PK_1$ porcine renal epithelial cell. In addition, the extract and fractions from broccoli sprouts showed strong scavenging effect of 1,1-diphenyl-2-picrylhydrazyl radical and the BuOH fraction exerted the strongest activity. Therefore, the BuOH fraction was evaluated as the most active fraction with strong radical scavenging activity among the fractions of broccoli flowers and sprouts. The present study suggests the antioxidative potential against free radical-induced oxidative damage of flowers and sprouts of broccoli. In addition, the BuOH fraction of broccoli is considered as the active fraction with antioxidative effect.

• 약학회지
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• 제44권4호
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• pp.371-377
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• 2000

In order to investigate the pharmacological properties of fractions of Astragali Radix and Polygalae Radix, the effects of the fractions on cerebral ischemia and subsequent reperfusion were studied. Brain ischemia was induced by bilateral common carotid artery occlusion in mongolian gerbil. Brains were recirculated for 30 mins after the 20 min occlusion. Methanol and butanol fractions of Astragali Radix and Polygalae Radix were administered orally 2 hrs before common carotid artery occlusion. Histological observations showed that brain ischemia induced severe brain damage evidenced by the presence of necrotic foci, edema and hemorrhage. This injury was prevented by the methanol fraction and butanol fraction of Polygalae Radix. The level of ATP in brain tissue significantly decreased in ischemic gerbils. This decrease was prevented by the pretreatment with butanol fraction of Polygalae Radix. In contrast, the levels of lactate and lipid peroxide were both elevated in ischemic gerbils. This elevation was inhibited by the pretreatments with methanol fraction and butanol fraction of Polygalae Radix. Our findings suggest that the Polygalae Radix improves ischemia-induced brain damage.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.31-36
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• 2000

High temperature and pressure materials in power plant are degraded by creep damage, if they are exposed to constant loads for long times, which occurs in the load bearing structures of pressurized components operating at elevated temperatures. Many conventional measurement techniques such as replica method, electric resistance method, and hardness test method for measuring creep damage have been used. So far, the replica method is mainly used for the Inspection of High temperature and pressure components. This technique is, however, restricted to applications at the surface of the testpieces and cannot be used to material inside. In this paper, ultrasonic evaluation for the detection of creep damage in the form of cavaties on grain boundaries or integranular microcracks are carried out. And the absolute measuring method of quantitative ultrasonic velocity technique for Cr-Mo material degradation is analyzed. As a result of ultrasonic tests for crept specimens, we find that the sound velocity is decreased as the increase of creep life fraction$({\Phi}_c)$ and also, confirmed that hardness is decreased as the increase of creep life fraction$({\Phi}_c)$ but the coefficient of ultrasonic attenuation is increased as the increase of creep life fraction$({\Phi}_c)$. Finally based on the result in this paper, it can be recognized that the ultrasonic techniques using velocities and attenuation coefficient factor are very useful non-destructive methods to evaluate the degree of material degradation in fossile power plants.

• Fisheries and Aquatic Sciences
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• 제13권1호
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• pp.26-35
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• 2010

In our previous study, we preliminarily demonstrated that Celluclast and Neutrase extracts exhibited the strongest $H_2O_2$-scavenging activities among five carbohydrases (Viscozyme, Celluclast, Termamyl, Ultraflo and AMG) and five proteases (Kojizyme, Alcalse, Flavourzyme Protamex and Neutrase) extracts. Thus, Celluclast and Neutrase extracts were selected for use in further experiments and were separated into four different molecular weight fractions (<5, 5-10, 10-30 and >30 kDa). Among them, the 5-10 kDa fraction showed the highest $H_2O_2$-scavenging activity. The 5-10 kDa fraction also strongly enhanced cell viability against $H_2O_2$-induced oxidative damage. Furthermore, the fraction reduced the proportion of apoptotic cells induced by $H_2O_2$, as demonstrated by decreased sub-G1 hypodiploid cells and decreased apoptotic body formation by flow cytometry. These results indicated that the 5-10 kDa fraction of the Celluclast and Neutrase extracts from S. coreanum exhibited strong antioxidant activity over $H_2O_2$-mediated cell damage in vitro.

• 대한화장품학회:학술대회논문집
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• 대한화장품학회 2003년도 IFSCC Conference Proceeding Book I
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• pp.142-160
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• 2003

Most consumers have noted hair damage following coloring treatments. Proper evaluation of hair bleaching products must be performed using quantitative assessments of hair damage, though they are difficult, because of the slight fluctuations in hair composition. In the present study, we utilized a sensitive evaluation method for hair damage and found that the amount of soluble protein fraction extracted from hair under a reducing condition, termed labile protein, dramatically increased after bleaching.(omitted)

• Computers and Concrete
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• 제22권1호
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• pp.63-70
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• 2018

The steel fiber reinforced concrete (SFRC) shows better performance under dynamic loading than conventional concrete in virtue of its good ductility. In this paper, a series of quasi-static experiments were carried out on the SFRC with volume fractions from 0 to 6%. The compressive strength increases by 38% while the tension strength increases by 106% when the fraction is 6.0%. The contact explosion tests were also performed on the ${\Phi}40{\times}6cm$ circular SFRC slabs of different volume fractions with 20 g RDX charges placed on their surfaces. The volume of spalling pit decreases rapidly with the increase of steel fiber fraction with a decline of 80% when the fraction is 6%, which is same as the crack density. Based on the experimental results, the fitting formulae are given, which can be used to predict individually the change tendencies of the blast crater volume, the spalling pit volume and the crack density in slabs with the increase of the steel fiber fraction. The new formulae of the thickness of damage region are established, whose predictions agree well with our test results and others. This is of great practical significance for experimental investigations and engineering applications.

• 한국해양공학회지
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• 제13권3호통권33호
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• pp.92-99
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• 1999

High temperature and pressure materials in power plant are degraded by creep damage, if they are exposed to constant loads for long times, which occurs in load bearing structures of pressurized components operationg at elevated temperatures. Many conventional measurement techniques such as replica method, electric resistance method, and hardness test method for measuring creep damgage have been used. So far, the replica method is mainly used for the inspection of high temperature and pressure components. This technique is, however, restricted to applications at the surface of the testpieces and cannot be used to material inside. In this paper, ultrasonic evaluation for the detection of creep damage in the form of cavaties on grain boundaries or intergranular microcracks were carried out. And the absolute measuring method of quantitative ultrasonic velocity technique for Cr-Mo material degradation was analyzed. As a result of ultrasonic tests for crept for specimens, we founded that the sound velocity was decreased as increase of creep life fraction(${phi}c$) and also, confirmed that hardness was decreased as increase of creep life fraction(${phi}c$).

• Environmental Analysis Health and Toxicology
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• 제15권4호
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• pp.147-155
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• 2000

In order to evaluate anti -oxidant activities and protective effect against oxidatve damage, DPPH radical scavenging activity and lipid peroxidation inhibitory activity were measured among methanol extracts prepared from natural medicinal plants. Fourteen natural medicinal plants which were reported to have anti -oxidative or anti-inflammatory effects were selected based on our previous report. In addition to the total methanol extracts, n-hexane, dichloromethane, ethylacetate, n-butanol and water fractions were prepared from each total extract. DPPH radical scavenging assay was performed against 14 total extracts and all samples showed dose-dependent activities in various extent. Among those, 6 samples, methanol extracts of Euryale ferox, paeonia suffruticosa, Areca catechu var. dulcissima, Cinnamomun cassia, Alpinia katsumadai and Betula platyphlla var. japonica showed IC$\sub$50/ value lower than 6.0 $\mu\textrm{g}$/ml. The highest DPPH radical scavenging activity was found in ethylacetate fraction of paeonia suffruticosa with IC$\sub$50/ value of 1.1 $\mu\textrm{g}$/ml. Analysis of lipid peroxidation inhibitory activity on hydrogen peroxide-induced oxidative damage in Chinese hamster lung fibroblast (V79-4) cells revealed that the highest inhibitory effect was observed in methanol extract of Betula platyhpylla var. japonica. Lipid peroxidation inhibitory activity was observed as a dose-dependent manner in all samples used in this study. Among fraction samples, ethylacetate fraction of Alpinia katsumadai had the strongest inhibitory activity with IC$\sub$50/ value of 0.9 $\mu\textrm{g}$/ml.