• Proceedings of the PSK Conference
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• 2003.04a
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• pp.145.1-145.1
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• 2003

Several lines of recent evidences have shown that several pro-inflammatory genes or mediators, such as inducible nitric oxide synthase (iNOS), cyclooxygenase-2 and cytokines (e.g., tumor necrosis factor $\alpha$ and interleukin-1$\beta$), are strongly expressed in the ischemic brain. Inflammation is now recognized as a significant contributing mechanism in cerebral ischemia because anti-inflammatory compounds or inhibitors of iNOS and cyclooxygenase-2 have been proven to reduce ischemic brain damage. (omitted)

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.148.1-148.1
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• 2003

The effects of methanolic extracts of Polygalae Radix (PR 100mg/kg) was tested to evaluate on the neuroprotective activity (92％ p<0.001) on global cerebral schemia. Based on bioassays guided fractionation, butanol soluble fraction (BtOH 25mg/kg) had the neuroprotive effect (87％ p<0.001) of global cerebral ischemia in rat. Oxygen free radical injury plays an important role in neuronal damage induced by brain ischemia and reperfusion. (omitted)

• Journal of the Korean Society for Heat Treatment
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• v.35 no.5
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• pp.239-245
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• 2022

The purpose of this study is to evaluate the degree of microstructural change of materials using ultrasonic nonlinear parameters. For microstructure change, isothermal heat-treated ferritic 2.25Cr steel and low-cycle fatigue-damage copper alloy were prepared. The variation in ultrasonic nonlinearity was analyzed and evaluated through changes in hardness, ductile-brittle transition temperature, electron microscopy, and X-ray diffraction tests. Ultrasonic nonlinearity of 2.25Cr steel increased rapidly during the first 1,000 hours of deterioration and then gradually increased thereafter. The variation in non-linear parameters was shown to be coarsening of carbides and an increase in the volume fraction of stable M6C carbides during heat treatment. Due to the low-cycle fatigue deformation of oxygen-free copper, the dislocation that causes lattice deformation developed in the material, distorting the propagating ultrasonic waves, and causing an increase in the ultrasonic nonlinear parameters.

• Geomechanics and Engineering
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• v.32 no.5
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• pp.541-551
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• 2023

Snap-buckling is one of the main failure modes of structures, because it will lead to the reduction of structural bearing capacity, durability loss and even structural damage. Boundary condition plays an important role in the research of engineering mechanics. Further discussion on the boundary conditions problems will help to analyze the dynamic and static behavior of structures more accurately. Therefore, in order to understand the dynamic and static behavior of curved beams more comprehensively, this paper mainly studies the nonlinear snap-through buckling and forced vibration characteristics of functionally graded graphene reinforced composites (FG-GPLRCs) curved beams with two different boundary conditions (including clamped-hinged and hinged-hinged) using Euler-Bernoulli beam theory (E-BBT). In addition, the effects of the curved beam radius, the GLPs distributions, number of GLPs layers, the mass fraction of GLPs and elastic foundation parameters on the nonlinear snap-through buckling and forced vibration behavior are discussed respectively.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.4
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• pp.423-430
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• 2014

In this study, the antioxidative effects for the extracts of purple sweet potato (Ipomoea batatas L. Lam.) were investigated. The purple sweet potato was extracted with 70% ethanol and the ethyl acetate fraction was obtained from the extracts. The yields of extract and ethyl acetate fraction were 39.2% and 3.49% per dried powder, respectively. To confirm the antioxidative effects of the extracts, free radical scavenging activities (1,1-diphenyl-2-picrylhydrazyl), total antioxidant capacity by luminol-dependent chemiluminescence assay and the protective effects against reactive oxygen species (ROS) in erythrocytes were measured. Free radical scavenging activities ($FSC_{50}$) of the 70% ethanol extract and ethyl acetate fraction were $90.16{\mu}g/mL$ and $7.69{\mu}g/mL$, respectively. The free radical scavenging activity of ethyl acetate fraction was higher than that of (+)-${\alpha}$-tocopherol ($8.98{\mu}g/mL$). Total antioxidant capacities ($OSC_{50}$) of the 70% ethanol extract and ethyl acetate fraction were $5.75{\mu}g/mL$ and $1.92{\mu}g/mL$, respectively. The capacity of ethyl acetate fraction was similar to L-ascorbic acid, known as a prominent water soluble antioxidant ($1.50{\mu}g/mL$). The cellular protective effects of the ethyl acetate fractions on the $^1O_2$-induced cellular damage of human erythrocytes were increased in a concentration dependent manner ($5{\sim}50{\mu}g/mL$). The ${\tau}_{50}$ value in $5{\mu}g/mL$ was 45.6 min which was higher than that of (+)-${\alpha}$-tocopherol in all concentrations. These results indicate that the ethyl acetate fraction of purple sweet potato (I. batatas) has the excellent antioxidative capacity and could be applicable to anti-aging cosmeceutical ingredients for skin aging inhibition.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.1
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• pp.11-20
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• 2014

In this work, the antioxidative effects and active component analysis of Gnaphalium affine D. DON. (G. affine) extracts were investigated. All experiments were performed with 70% ethanol extract, ethyl acetate fraction and aglycone fraction of the G. affine extract. The free radical (1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activity ($FSC_{50}$) of ethyl acetate fraction ($6.15{\mu}g/mL$) of the G. affine was higher than that of (+)-${\alpha}$-tocopherol ($8.89{\mu}g/mL$), which is known as a reference control. Reactive oxygen species (ROS) scavenging activities ($OSC_{50}$) of the 70% ethanol extract ($1.60{\mu}g/mL$), ethyl acetate fraction ($0.075{\mu}g/mL$) and aglycone fraction ($2.28{\mu}g/mL$) of extract of G. affine on ROS generated in $Fe^{3+}$-EDTA/$H_2O_2$ system using the luminol-dependent chemiluminescence assay were much higher than that of L-ascorbic acid ($6.88{\mu}g/mL$). The cellular protective effects of 70% ethanol extract (${\tau}_{50}$ = 52.0 min) and aglycone fraction of the extract (${\tau}_{50}$ = 60.6 min) on the $^1O_2$-induced cellular damage of human erythrocytes were exhibited the higher protective effect than (+)-${\alpha}$-tocopherol (${\tau}_{50}$ = 38.0 min), known as a lipophilic antioxidant. TLC and HPLC were used to analyse active components in the aglycone fraction of the extract. Results showed that luteolin and apigenin were main components. These results suggest that the G. affine extract can be applied to an effective antioxidant in scavenging ROS including radicals.

• Journal of the Korean Applied Science and Technology
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• v.31 no.4
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• pp.771-780
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• 2014

The antioxidative effects and component analysis of the Melaleuca quinquenervia leaf extracts were investigated. All experiments were performed with 50% ethanol extract, ethyl acetate fraction and aglycone fraction obtained from dried M. quinquenervia leaves. The DPPH (1,1-phenyl-2-picrylhydrazyl) scavenging activity ($FSC_{50}$) of ethyl acetate fraction ($10.05{\mu}g/mL$) of M. quinquenervia leaf extracts was similar to (+)-${\alpha}$-tocopherol($8.89{\mu}g/mL$) known as a typical antioxidant. Reactive oxygen species (ROS) scavenging activities ($OSC_{50}$) of the ethyl acetate fraction ($1.61{\mu}g/mL$) and aglycone fraction ($1.07{\mu}g/mL$) of leaf extracts of M. quinquenervia on ROS generated in $Fe^{3+}-EDTA/H_2O_2$ system using the luminol-dependent chemiluminescence assay were similar to that of L-ascorbic acid ($1.50{\mu}g/mL$). The cellular protective effect of the extracts on the rose bengal sensitized photohemolysis of human erythrocytes was increased in a concentration dependant manner ($1{\sim}50{\mu}g/mL$). Especially, the cellular protective effects of Aglycone fraction (${\tau}_{50}=158.80min$) and 50% Ethanol extract (${\tau}_{50}=50.1{\pm}0.2min$) on the $^1O_2$-induced cellular damage of human cells were exhibited the higher than (+)-${\alpha}$-tocopherol (${\tau}_{50}=38.0min$). TLC and HPLC were used to analyse active components in the ethylacetate fraction of the extracts. Results showed that avicularin and quercetrin were active components of the extracts. These findings suggest that the M. quinquenervia leaf extracts can be applied to new cosmetics products as an effective antioxidant ingradient.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.43 no.2
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• pp.175-187
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• 2017

In this study, the antioxidant effect and component analysis for extract and fractions of Cardiospermum halicacabum leaf were investigated. All experiments were performed with 50% ethanol extract, ethyl acetate fraction and aglycone fraction obtained from dried C. halicacabum leaf. The yields of extract and fractions were 16.4, 0.9 and 0.3% per dried powder, respectively. DPPH (1,1-phenyl-2-picrylhydrazyl) radical scavenging activity ($FSC_{50}$) of ethyl acetate fraction ($92.5{\mu}g/mL$) was the greatest radical scavenging activity, but lower than (+)-${\alpha}$-tocopherol ($8.9{\mu}g/mL$). In reactive oxygen species (ROS) scavenging activity (total antioxidant capacity, $OSC_{50}$) on ROS generated in $Fe^{3+}-EDTA/H_2O_2$ system, aglycone fraction ($4.2{\mu}g/mL$) was the highest total antioxidant capacity and similar to L-ascorbic acid ($1.5{\mu}g/mL$). The cellular protective effects of C. halicacabum leaf extract and fractions on the $^1O_2$-induced cellular damage of human erythrocytes were exhibited at all concentration-dependent ($5.0-25.0{\mu}g/mL$). Especially, aglycone fraction (${\tau}_{50}$, 76.4 min) in $25.0{\mu}g/mL$ showed the most protective effect among extracts. Components of the ethyl acetate fraction obtained from C. halicacabum extracts were analyzed by TLC, HPLC chromatogram and LC/ESI-MS. Results showed that the ethyl acetate fraction contained some flavonoids, such as apigenin-7-O-glucuronide, apigenin-7-glucosdie and quercitrin hydrate. These results suggest that the extracts and fractions of C. halicacabum leaf may be applied as antioxidant functional cosmetic raw materials.

• Journal of Nutrition and Health
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• v.37 no.8
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• pp.633-644
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• 2004

This study was performed to investigate effect of dried powders and ethanol extracts of garlic flesh and peel on antioxidative capacity in 16-month- old rats. Forty Sprague-Dawley male rats weighing 618.1$\pm$6.5g were blocked into five groups according to body weight and raised for 3 months with experimental diets containing 5% (w/w) of dried powders of garlic flesh or peel, or ethanol extracts from equal amount of each dried powder. Total polyphenols, flavonoids, /3 -carotene, vitamin C, vitamin E, and total antioxidant status (TAS) levels were determined in garlic preparations. Thiobarbituric acid reactive substances (TBARS) levels in plasma, liver and VLDL + LDL fraction, oxidative DNA damage (8-hydroxy-2' -deoxyguanosine, 80HdG) in kidney, xanthine oxidase (XO) activities in plasma and liver, superoxide dismutase (SOD) activities in erythrocyte and liver, and carotenoid concentration, and total antioxidant status (TAS) in plasma were measured. Total polyphenols and flavonoids contents in garlic preparations were highest in peel ethanol extract. Vitamin C content was not different significantly among preparations, but peel powder contains slightly more vitamin C. The content of $\beta$-carotene was highest in peel ethanol extract and vitmain E content was highest in flesh ethanol extract. The highest level of TAS was observed in peel ethanol extract. Plasma TBARS levels in all the experimental groups were found to be significantly lower than control group, and TBARS concentration in VLDL + LDL fraction was decreased in all the experimental groups in comparison to control group. Also levels of 80HdG in kidney in experimental groups were lower than that of control group. Plasma and liver XO activities were. decreased in all experimental groups, and erythrocyte and liver SOD activities were higher in experimental groups compared to control group. All experimental groups also showed higher plasma TAS levels than control group. Especially, garlic flesh powder group was significantly lower in plasma and liver XO activities, and significantly higher in erythrocyte and liver SOD activities than control group. Moreover, plasma TBARS level and kidney 8OHdG level were decreased in flesh powder group. In conclusion, garlic diets showed effect of improving antioxidative capacity in 16-month old rats, especially, garlic flesh powder was prominent in inhibiting XO activity, promoting SOD activity and decreasing kidney 8OHdG level among experimental groups.

• Composites Research
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• v.32 no.2
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• pp.90-95
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• 2019

Sloshing impact loads on liquefied natural gas (LNG) carr iers are the main issue of damage to the insulation system in LNG cargo containment system (LNG CCS). The damage to the insulation system would be fatal in maintaining a temperature-savings environment in LNG CCS. The typical method is to enhance the insulation materials that can maintain a constant cryogenic temperature. Insulation materials consist of polyurethane foam and plywood, an adhesive for bonding these two materials. This study intends to improve the absorption energy of the material when the impact load is applied by creating a glass bubble/epoxy composite resin as part of the insulation. The experimental scenarios consider the effect of temperature ($20^{\circ}C$, $-163^{\circ}C$), glass bubble weight fraction in epoxy resin through free fall experiments. Experiments have shown that if the glass bubble additive reaches 20 wt.%, the cryogenic absorption energy is a maximum performance and that 0 wt.% has a maximum ambient absorption energy. However, the agglomeration has been occurred due to deterioration of the stirring performance if weight fraction was 20 wt.% and the result of 0 wt.% have been revealed that ambient absorption energy is significantly lower.