• 한국연소학회지
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• 제3권1호
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• pp.11-19
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• 1998

The influence of oxidant addition on soot formation is investigated experimentally with ethylene, propane and mixture fuel co-flow diffusion flames. Oxidant addition into fuel shows the increase of integrated soot volume fractions for ethylene, ethylene/ethane and ethylene/methane mixture flames. However, the increase of integrated soot volume fraction with oxidant addition was not significant for propane and ethylene/propane mixture flames. This discrepancy is explained with $C_2\;and\;C_3$ chemistry at the early stage of soot formation process. The oxidant addition increases the concentration of $C_3H_3$ in the soot formation region, and therefore, enhances soot formation process. A new soot formation rate model that includes both dilution effect and chemical effect of oxygen is suggested to interpret the increase of integrated soot volume fractions with oxidant addition into ethylene. Also, the role of adiabatic flame temperature for the chemical effect of oxygen addition into fuel was reviewed. The influence of oxidant or diluent addition into fuel on soot formation process are the fuel dilution effect, the adiabatic flame temperature altering effect and/or the chemical effect of oxygen. Their relative importance could change with fuel structure and adiabatic flame temperature.

• Bulletin of the Korean Chemical Society
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• 제26권11호
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• pp.1743-1748
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• 2005

This work presents that carbon dioxide, which is a main contributor to the global warming effect, could be utilized as a selective oxidant in the oxidative dehydrogenation of ethylbenzene. The dehydrogenation of ethylbenzene over alumina-supported vanadium-antimony oxide catalyst has been studied under different atmospheres such as inert nitrogen, steam, oxygen or carbon dioxide as diluent or oxidant. Among them, the addition of carbon dioxide gave the highest styrene yield (up to 82%) and styrene selectivity (up to 97%) along with stable activity. Carbon dioxide could play a beneficial role of a selective oxidant in the improvement of the catalytic behavior through the oxidative pathway.

• BMB Reports
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• 제45권10호
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• pp.565-570
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• 2012

We recently reported that a water extract of laurel or turmeric, 1,8-cineole enriched fractions, showed hypolipidemic activity in the zebrafish model. Therefore, the present study investigated the cineole's anti-oxidant and anti-inflammatory activities in lipoprotein metabolism in vitro and in vivo. Cineole had inhibitory effects on cupric ion-mediated oxidation of lipoproteins in general, while simultaneously enhancing ferric ion removal ability in high-density lipoprotein (HDL). Hypercholesterolemia was induced in zebrafish using cholesterol-feeding treatment, 4% cholesterol, for 3 weeks. After feeding with or without the addition of cineole, the results revealed that cineole possessed lipid-lowering and anti-inflammatory activities in hypercholesterolemic zebrafish. In addition, serum amyloid A and interleukin-6 levels were lowered and lipid accumulation was decreased in the liver. Conclusively, 1,8-cineole was found to have anti-oxidant activities in lipoprotein metabolism both in vitro and in vivo with simultaneous reduction of lipid accumulation in the liver of zebrafish.

• 한국식품영양학회지
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• 제28권1호
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• pp.40-46
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• 2015

Hamcho (Salicornia herbacea) extracts were evaluated for total polyphenol content, antioxidant and pro-oxidant activities. The total polyphenol content was 1.81 g and 0.72 g per 100 g of dried sample in water and ethanol extracts respectively. Both water and ethanol extracts of Hamcho significantly exhibited antioxidant activity. The scavenging activity of hydroxyl radical was 13.8~26.2% and 14.2~16.0% in water and ethanol extracts respectively. The inhibitory effect of conjugated diene formation was 24.6~39.1% and 28.4~39.6% in water and ethanol extracts respectively. However, pro-oxidative effect was also observed in the Hamcho extracts. The Hamcho water extract showed the pro-oxidant effect by enhancing the formation of hydroxyl radical and conjugated diene. The ethanol extract of Hamcho induced conjugated diene formation at 0.5 mg/mL but not at 1 mg/mL. The hydroxyl radical formation was not induced by the Hamcho ethanol extract. Taken together, these results show that Hamcho extracts can act as pro-oxidants by generating hydroxyl radical or conjugated diene in addition to their antioxidant properties. Therefore, this study suggests that the physiological properties of Hamcho and its use as food materials should be considered with caution because antioxidant dietary plants such as Hamcho possess possible adverse effects induced by pro-oxidant activity.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 학술대회 논문집 전문대학교육위원
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• pp.9-12
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• 2000

A new type electrolyzing cell with slits on parallel plate electrodes and wire-to-cylinder type electrode system has been proposed instead of the conventional parallel plate type. An investigation was carried out on the effect of the number and size of slits on ion precipitation and oxidant generation characteristics, evidenced by eliminated space charge limiting action and by elevated electric fields in active interelectrode spacing. And it is also studied on the effect of the diameter of wire electrode to ion precipitation and oxidant generation characteristics. With electrode with 48 slits, very oxidants generation water of 3.1 [ppmm] and 19.0 [ppmm] in positive electrode side were obtained with tap water and 0.1 [wt%] NaCl dissolved tap waterfed. In addition, with wire-to-cylinder type electrode system, it is found that oxidant contained water of 0.48 [ppmm] and 5.46 [ppmm] in positive electrode side were obtained with tap water and 0.1 [wt%] NaCl dissolved tap water fed for the case of discharge electrode diameter of 0.5 [$mm{\phi}$]. Consequently, very high ion precipitation and dense oxidant generation characteristics can be realized by having slits on the electrodes of conventional cell as these slits increase the electric fields and decrease the space charge limiting actions in interelectrode spacing.

• 생명과학회지
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• 제26권7호
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• pp.782-788
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• 2016

본 연구에서는 화장품의 천연소재로 사용 가능함을 알아보기 위해 추출부위가 각각 다른 총 11종의 자생식물의 항산화, 항주름에 관한 생리활성 효능을 스크리닝 하였다. DPPH scavenging assay 측정결과 100 μg/ml 농도에서 70% 넘는 활성을 나타낸 시료는 순비기나무, 송이고랭이, 방울고랭이, 큰고랭이, 자귀풀이었다. Hydrogen peroxide scavenging assay 측정결과 1,000 μg/ml 농도에서 물꼬챙이골을 제외한 10종이 90%넘는 활성을 나타내었다. Xanthine oxidase scavenging assay 측정결과 1,000 μg/ml 농도에서 순비기나무(Leaf; 86.3%)가 가장 높은 활성을 나타냈다. 4가지 항산화 실험에서 모두 효능이 우수하게 나온 시료는 순비기나무, 송이고랭이, 방울고랭이, 큰고랭이, 자귀풀이며 그중 collagenase 저해활성 측정결과 방울고랭이가 가장 높은 저해 활성을 나타내어 항산화 및 항주름에 효능이 있는 시료로 나타났다. 이러한 결과를 바탕으로 활성이 높은 자생식물은 화장품에 사용되는 천연소재로 이용이 가능한 좋은 수종으로 판단된다.

• Journal of Nutrition and Health
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• 제30권9호
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• pp.1061-1066
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• 1997

This study was undertaken to evaluate the effect of 4 weeks of $\alpha$-tocopherol(800 I.U./d) supplementation on oxidant stress of eleven female aerobic -majoring students during rest and exercise. Changes in the activity of the antioxidant enzyme glutathione peroxidase were also studied. Serum $\alpha$-tocopherol concentration was significantly increased with vitamin E supplementation(710.1$\pm$113.8$\mu\textrm{g}$/dl vs. 1,485,8$\pm$105.2$\mu\textrm{g}$/dl). In addition, serum MDA concentration, an index of lipid peroxidation, significantly decreased after vitamin E supplementation. However, MDA values after exercise increased to pre-supplementation levels. Serum glutathione peroxidase activity significantly increased with vitamin E supplementation. The enzyme activity showed a trend toward decrease after exercise. Serum cholesterol values were not significantly affected by vitamin E supplementation. However, serum triglycerides significantly increased after supplementation against oxidative stress during resting periods. These supplements appraently work by decreasing lipid peroxidation and increasing glutathione peroxidase activity. However, vitamin E supplementation did not prevent exercise-induced increases in lipid peroxidation.

• 대한한방내과학회지
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• 제18권1호
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• pp.147-155
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• 1997

This study was undertaken to determine whether Salviae-radix (SVR) exraction exerts benefical effect against oxidant-induced inhibition of tetraethylammonium (TEA) uptake which is actively secreted by renal proximal tubules. TEA uptake increased as function of incubation time to 60 min. When renal cortical slices were exposed to 50 mM $H_2O_2$, TEA uptake was significantly inhibited. The inhibition was significantly protected by addition of 0.5% SVR extraction. The benefical effect of SVR was dose-dependent over the concentration range of 0.1-1%; $H_2O_2$ (50 mM)-induced inhibition of TEA uptake was completely protected by 0.5-1% SVR extraction. $H_2O_2$ increased LDH release which was accompanied by an increase in lipid peroxidation in renal cortical slices. These changes were prevented by 0.5% SVR. These results suggest that SVR exerts benefical effect against oxidant-induced impairment of membrane transport function, this effect may be due to by an antioxidant action.

• 대한본초학회지
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• 제27권2호
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• pp.93-97
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• 2012

Objectives : The Astragalus membranaceus has been used to diuretic, tonic, anti-viral, anti-oxidant activities in oriental herb medicine, and in each experiment, proved in this effects. Root of A. membranaceus includes according to flavonoid, saponin, polysaccharide, thus it has been studied for anti-oxidant, anti-inflammatory, anti-cancer activities. However, previous researches have been performed with being limited mainly to food industry. The present study was conducted anti-oxidative activity of A. membranaceus extracts. In addition, The objective of the present study was to determine the possibility for the application of emulsions in the development of A. membranaceus for cosmetics. Methods : In this study, aimed SOD like activity of A. membranaceus extract, effects of A. membranaceus extract on viscoelastic properties of emulsion was measured using rheometer. Results : In the results, 1, 3-butylene glycol extract of A. membranaceus efficiently reduce the active oxygen, SOD like activity of more than 40% decrement depend on concentration. And A. membranaceus extract increase the modulus of elasticity of emulsion, therefore A. membranaceus extract have not influence on stability loss. As such, the A. membranaceus extracts will remain stable when applied to emulsions or skin products. Conclusions : In consequence of this study, A. membranaceus extract can be effectively used in cosmetic emulsions when the relation between natural product extracts and formulation of cosmetics is elucidated. It is highly recommended that rheology be applied to determine the optimal extract concentration for cosmetic formulations.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.39-39
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• 2017

In Asia, sweet potato (Ipomoea batatas) is a very important crop for starch production. Approximately 74.3% of the total sweet potato production quantity is produced in Asia (FAO, 2014) and China is the largest producer of sweet potato. Post-harvest management is particularly important because it is difficult to maintain the quality as well as quantity of sweet potatoes. Despite the importance of post-harvest management, researches on sweet potato have been focused on production-related study such as breeding of new variety, improved techniques of cultivation, so there is limited research on storage after harvest. Curing is a normal practice after sweet potato harvest to promote wound healing and extend postharvest storage life. In Korea, harvested sweet potatoes are usually cured for 4 to 7 days at $30-33^{\circ}C$ and 80-95% relative humidity within one week. Since the optimum storage temperature of sweet potato is regarded as $15-20^{\circ}C$, additional facilities and costs are required to raise the temperature for curing. However, the majority of small farmers do not have the capacity to provide additional facilities and costs. This study was initiated to suggest a new curing method to accelerate the wound healing by applying chemical oxidation to the wound surface of sweet potato. Oxidative stress is known to play an important role in the synthesis of secondary metabolites including lignin. In addition, chemical oxidation can be applied to prevent spoilage caused by microorganisms. Powerful gaseous oxidant with excellent penetration ability and superior sterilization effect was selected for this study. Lignification, weight loss, and spoilage rate of artificially wounded sweet potatoes were investigated after oxidant fumigation. There were clear differences in morphological analysis such as lignification pattern, lignin deposition color, and continuity of lignified cell layers between oxidant-fumigated sweet potatoes and control. These results show that gaseous oxidant can be used to supplement or replace the curing practice, to improve shelf-life as well as curing cost reduction.