• Food Science and Biotechnology
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• v.18 no.2
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• pp.312-316
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• 2009

Antioxidant-rich oils were extracted from different parts of sea buckthorn berry with supercritical $CO_2$ (SC-$CO_2$) and n-hexane. The functional components were analyzed and the extracts were screened for their potential as radical scavengers in 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), 2,2'-azinobis-3-ethylbenzotiazoline-6-sulphonic acid (ABTS), galvinoxyl systems. Minor differences were found in fatty acid composition of oils extracted by the two methods. Seed oil contains the highest content of tocopherols while pulp oil and whole berry oil possessed higher concentration of carotenoids. Whole berry oil, pulp oil, and seed oil extracted by SC-$CO_2$ showed 91.7, 90.9, and 93.5% radical scavenging activity (RSA) at 6 mg/mL towards DPPH and 74.3, 54.3, and 74.8% towards galvanoxyl radical at 10 mg/mL. The hexane-extracted oils showed similar scavenging ability. However, the oils obtained by hexane showed significantly higher RSA (p<0.05) than those obtained by SC-$CO_2$ while whole berry oil has the highest RSA towards ABTS among 3 oil samples.

• 연구논문집
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• s.28
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• pp.49-58
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• 1998

In order to analyse the scavenging efficiency in a poppet valve type 2-stroke engine. visualization of scavenging flow and quantitative experiments for measuring scavenging efficiency were performed. The effect of shroud angle in RSSV which was developed by KIMM was evaluated under steady flow rig applying single-cycle method. Also dynamic simulator was used by using gas sampling with $CO_2$ and $O_2$gas. The $90^circ$ shroud RSSV was found to be the highest efficient system, and single-cycle and dynamic simulator test are very effective to save time and cost for the development of a 2-stroke engine.

• Journal of the Korean Applied Science and Technology
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• v.31 no.2
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• pp.285-295
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• 2014

Citrus essential oil were extracted from citron peel of cultivated in Gohong (CCP) using environmentally friendly supercritical carbon dioxide method. Antioxidant activity and aroma composition of the essential oils extracted by the SC-$CO_2$ method were evaluated by comparing with those extracted by organic solvent method. Fatty acid composition, DPPH scavenging, and antioxidant activity of the oils obtained by different extraction condition of SC-$CO_2$ method were investigated and their antioxidant activities were compared with commercially available lavender, eucalyptus and tea tree oils. As the results, linoleic acid was most abundantly found from CCP oil extracted by the SC-$CO_2$ method and cis-11,144-eicosadienoic acids was second abundantly found. Radical scavenging ability of DPPH was 98% when the concentration of CCP oil was 50 mg/mL. This scavenging ability increased with the increase of oil concentration. On the other hand, flavonoids content (84 mg/100g) of the CCP oil extracted by the SC-$CO_2$ method was slightly higher than that (75 mg/100g) by hexane extraction. The results, obtained from CCP oil by GC-MS, indicated that, among 66 components, the content of terpenes was 55.8% and limonene was 27.3%.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.22 no.2
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• pp.115-123
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• 1996

Methanolic aqueous extracts of 100 plants were screened for antioxidative activity using Fenton's reagen/ethyl linoeate system and free radical scavenging activity using DPPH free radical generating system. The results suggest that at least six plants including Eugenia caryophyllata, Alpinia offiicinarum, Rhus verniciflua, Curcuma longa, Rheum palmatvm and Evodia officinalis may be the potential sources of antioxidant, But only one plant, Cornus officinalis, may be the potential source of free radical scavenger from natural plants.

• Preventive Nutrition and Food Science
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• v.12 no.3
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• pp.177-180
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• 2007

Tocotrienols (T3) are minor plant constituents found abundantly in rice bran, which provide a significant source of vitamin E in animal feeds. T3 was reported to have an intrinsic hypocholesterolemic effect by inhibiting HMG-Co A reductase. It has similar antioxidative properties as tocopherols in food and biological system due to their similar chemical structures. However, the antioxidant activity and mechanism of T3 to scavenge free radicals and to inhibit the peroxidation of linoleic acid are less understood. The purpose of this study was to investigate the scavenging effect of T3 on free radicals and its inhibition of peroxide formation. Free radical scavenging activity was monitored by the DPPH (1,1-diphenyl-2-picrylhydrazyl) method whereas inhibition of linoleic acid peroxidation was evaluated using the thiocyanate method. Thiobarbituric acid (TBA) test was used to determine malonaldehyde formation from linoleic acid peroxidation. Free radical scavenging activity increased with increasing concentration levels of T3. T3 exhibited 38.2, 78.6, 92.7 and 96.2% radical scavenging activity at concentrations of 2, 8, 32 and 128 ppm, respectively. At 128 ppm, it was highly effective in inhibiting linoleic acid peroxidation. The activity of T3 evaluated by the thiocyanate method showed low absorbance values indicating a high level of antioxidant activity. All treatments showed similar trends in antioxidant activity when evaluated by both the thiocyanate method and TBA test.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.32 no.3 s.58
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• pp.193-200
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• 2006

We investigated the effect of moisturizing and anti-oxidation of Astragalus membranaceus (Astragali Radix) root extract with respective to growing districts and extract methods for the purpose of development of cosmetic ingredients. Astragalii Radix was collected in Jecheon, Jeongseon, Taebaek, and Yeongju in Korea and China as growing districts. Formononetin was determinated by HPLC method as one of the various active agents in Astragalus membranaceus root extract. The 75% ethanol extract demonstrated to be more effective than $H_2O$-extracted one for a scavenging activities to DPPH radicals and reactive oxygens. The 75% ethanol extract showed $IC_{50}$ (50% scavenging concentration) of 2.162 mg/mL and 2.981 mg/mL in case of free radical scavenging activity test and reactive oxygen scavenging activity test, respectively Especially, free radical scavenging activity of isoflavonoids isolated from ethylacetate fraction was similar to scavenging activity of genistein. Astragalus membranaceus root extract of Jecheon district by sonicating extraction method was more effective in skin hydration compared with others.

• Journal of the Korean Society of Industry Convergence
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• v.22 no.3
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• pp.259-264
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• 2019

In this study, we experiment by making and designing of compression ignition diesel engine witch has air cooling, 2-cylinder and 2-strokes. Also, we make controller witch can control injection timing and period by arbitrary manual operation for change of injection timing. We also study experimentally in change about pressure and power of combustion chamber by increasing density of air which comes into cylinder because of increasing scavenging pressure. Through this, we confirmed that output change and scavenging pressure can develop performance of the engine by scavenging efficiency of a chamber and development of volume efficiency.

• Transactions of the Korean hydrogen and new energy society
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• v.19 no.2
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• pp.139-144
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• 2008

The focus of this research is that the scavenging aspect of in-cylinder is visualized by the PIV method and its characteristic is analyzed so that the scavenging performance of the free piston hydrogen fueled engine can improve with loop scavenging. As the results, the piston of convex type shows the best scavenging performance among the presented pistons. In case of the abnormal expansion, the scavenging of area between cylinder head and cylinder wall doesn't operate well.

• Korean Journal of Plant Resources
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• v.29 no.3
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• pp.289-296
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• 2016

This study was executed to evaluate the immune activity, nitrite scavenging activity and ABTS radical scavenging activity against extracts of various concentration of ethanol solvent from Codonopsis lanceolata cultured at 6 local regions. The immune responses from both human T and B cell line was significantly enhanced in the cell growth compared to control while the cell growth was influenced at a certain period of culture. The results revealed that the cell growth of both human T and B cell was altered in a time dependent manner. The nitrite scavenging activity of ethanol extracts from various solvent concentration of C. lanceolata were affected by pH. At a pH of 1.2, the nitrite scavenging effect of all of the extracts tested observed higher than that of the other two pH ranges. There was no distinct detection of nitrite scavenging effects of the pH range 6.0. The ABTS radical scavenging activity was progressively increased in a dose-dependent manner, and the activity was the highest in 100% ethanol extract. The result from this investigation suggests that the extract of Codonopsis lanceolata could be an addition to basic medicine for immune modulation and natural food additives.

• Korean Journal of Pharmacognosy
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• v.34 no.4 s.135
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• pp.324-326
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• 2003

The methanol (MeOH) extract and ist fractions of Taraxacum mongolicum (Compositae) were examined for their scavenging effects on 1,1-diphenyl-2- phenylhydrazyl (DPPH) and superoxide radicals, and hepatoprotective effects on tacrine-induced cytotoxicity in human hepatoma cell line, Hep G2 cells. Both methylene chloride $(CH_2Cl_2)$ and butanol (n-BuOH) soluble fractions of the MeOH extract showed the free radicals scavenging and hepatoprotective effects. From these results, it is suggested that hepatoprotective effect of these fractions partly relies on their free radical scavenging activity.