• Korean Journal of Food Science and Technology
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• v.48 no.3
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• pp.208-213
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• 2016

This study evaluated the in vitro radical scavenging and ${\alpha}$-glucosidase inhibitory activities of dried daraesoon (shoot of hardy kiwi) during cooking involving rehydration and subsequent heating at $180^{\circ}C$ with or without perilla oil. Pigments and antioxidants were quantified by HPLC and spectrophotometry. Unlike the tocopherol content, the polyphenol, flavonoid, chlorophyll, and carotenoid contents as well as the DPPH radical scavenging and ${\alpha}$-glucosidase inhibitory activities of daraesoon extract were significantly decreased by rehydration (p<0.05). Heating the rehydrated daraesoon for 10 or 20 min increased its radical scavenging activity irrespective of perilla oil addition, whereas the ${\alpha}$-glucosidase inhibitory activity increased significantly only after heating with perilla oil (p<0.05). During cooking, changes in both activities showed a similar pattern to that showed by polyphenol content changes. These results suggest that the health functionality of daraesoon can be enhanced by an appropriate cooking process that retains polyphenols.

• Journal of the Korean Electrochemical Society
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• v.19 no.4
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• pp.141-147
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• 2016

In this study, homo and copolymers of 2,2,6,6-tetramethyl-4-piperidyl methacrylate(TMA) and synthesized styrene derivative, 2,2,6,6-tetramethylpiperidine-4-vinylbenzyl ether(TVBE) were obtained by radical polymerization and oxidized to produce corresponding polymer radicals. The polymer radicals were mixed with carbon black, binders and coated onto Al current collector. The battery performance is then characterized by fabricating coin cells. As results, the polystyrene based organic radicals show lower oxidize efficiency and discharge capacity than methacrylate based one. However, the former shows better capacities from discharge experiments performed at $60^{\circ}C$ which suggests a possible way to overcome the high temperature fade out of performance in usual organic radical batteries. Also as expected, an excellent C-rate performance is observed in all the cells consisted of organic polymer radicals.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.10
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• pp.1601-1605
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• 2004

To develop the functional food, methanol extracts of dried plantain (Plantago asiatica L.) was fractionated in hexane, chloroform, ethyl acetate, butanol and aqueous fraction. DPPH radical scavenging effect, reducing power, nitrite scavenging effect and antimicrobial activities of these fractions were investigated. Ethyl acetate fraction among these fractions showed the highest effect of all experiments. Ethyl acetate fraction showed about 60% scavenging effect on the DPPH radicals at 400 $\mu$g/5 mL. Nitrite scavenging effect of ethyl acetate and butanol fraction was more than 70~80% at concentration above of 500 $\mu$g. Among various solvent fractions from methanol extracts of plantain, ethyl acetate fraction showed the highest inhibitory effect on the microorganism such as Staphylococcus aureus, Bacillus cereus and Vibrio parahaemolyticus at 5 mg/disc.

• Journal of Applied Biological Chemistry
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• v.60 no.2
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• pp.185-190
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• 2017

Antioxidative ability of 50% ethanol extract from leaves of Leucaena leucocephala (Lam.) de Wit was investigated. The extraction yield, total polyphenols and total flavonoids of the ethanol extract were $18.3{\pm}0.40%$, $121.3{\pm}11.04{\mu}g$ gallic acid equivalents/mg and $105.2{\pm}2.77{\mu}g$ quercetin equivalents/mg, respectively. The ethanol extract possessed the antioxidative activities such as free radical, cation radical, and nitrite scavenging activities as well as reducing power and lipid peroxidation inhibitory activity. These antioxidative activities of the ethanol extract increased in proportion to the extract concentration. $EC_{50}$ values for free radical scavenging, cation radical scavenging nitrite scavenging, and reducing power were $133.51{\mu}g/mL$, $667.22{\mu}g/mL$, 2.58 mg/mL, and $250.00{\mu}g/mL$, respectively. Polyphenols and flavonoids are suggested to be the key contributors for the antioxidative ability of the ethanol extract from Leucaena leucocephala leaves.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.3
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• pp.296-308
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• 2010

The peroxone process overcomes many of the limitations associated with conventional and advanced water treatment systems using chlorine disinfection and ozone oxidation processes. Ozone and hydrogen peroxide generate highly reactive hydroxyl free radical which oxidize various organic compounds and has highly removal efficiency. The key issue to operate peroxone process is developing the method to achieve high process effectiveness when scavengers that inhibit generation of OH radicals or consume OH radicals are co-existing in the process. Also many studies, to minimize inorganic oxidative by-products such as bromate and to reduce disinfection by-products after chlorination behind peroxone process, are needed. And we should consider the excess residual hydrogen peroxide in the water. On-line instruments and control strategies need to be developed to ensure effective and robust operation under conditions of varying load. If problems above mentioned are solved, peroxone process will be applied diversely for water treatment.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.35 no.3
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• pp.251-256
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• 2009

Investigation of antioxidative constituents from the ethanol extract of Quercus gilva branches led to the identification of four compounds; catechin (1), epi-catechin (2), tyrosol (3) and tiliroside (4). The antioxidative activity was examined using DPPH radical and superoxide anion radical scavenging method. The isolated compounds 1, 2, 3 and 4 exhibited 94.2 %, 93.4 %, 33.6 % and 11.2 % scavenging activities respectively against DPPH radicals at the concentration of $100{\mu}L$/mL. As well, the compounds $1{\sim}4$ showed respectively 60.2 %, 35.1 %, 20.6 %, 4.5 % inhibition activities against superoxide anion radicals at $200{\mu}L$/mL. Interestingly, the compounds $1{\sim}4$ were isolated for the first time from Quercus gilva Blume.

• Journal of the Korean GEO-environmental Society
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• v.11 no.8
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• pp.41-47
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• 2010

This study was conducted to assess the applicability of pilot scale system and to evaluate the treatment efficiency on operational parameters such as humic acid concentration, initial pH and air flow rate on the ozone/peroxyl radical reaction system. The decolorization of ozone/peroxyl radical system was higher than that of only process. Removal efficiency of ozone/peroxyl radical system was generally increased with the increase of intial concentration of humic acid but decreased over the range of 30mg/L. Treatment efficiency of HA at acid pH was smaller compared to that of neutral or basic pH and increased with increasing the air flow rate from 1L/min to 3L/min. In pilot-scale test, average removal of TOC and $COD_{Cr}$ was about 70% and 60%, respectively and ozone/peroxyl radical reaction system was indicated a potential in water treatment application.

• Korean Journal of Food Science and Technology
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• v.50 no.2
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• pp.209-215
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• 2018

To evaluate the radical scavenging activity of phenolic-rich fractions of Gardenia jasminoides, we first measured the levels of total polyphenols in hexane, ethyl acetate, and butanol fractions from the extract of G. jasminoides. The ethyl acetate fraction of G. jasminoides extract (GJ-EA) showed high level of phenolics, potent reducing power, and 2,2-diphenyl-1-picrylhydrazyl/2,2'-azino-bis 3-ethylbenzothiazoline-6-sulfonic acid radical scavenging effect. In addition, GJ-EA inhibited the overproduction of nitric oxide in lipopolysaccharide-activated BV-2 microglia. Furthermore, we found that GJ-EA suppressed $H_2O_2$-induced PANC-1 pancreatic cancer cell proliferation in a concentration-dependent manner and also reduced their migratory ability. These results suggest that GJ-EA may be a good source for functional foods with antioxidant and chemo-preventive activities.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.2
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• pp.139-144
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• 2012

A numerical simulation has been performed to investigate effects of toluene mixing on soot formation in pure ethylene opposed-flow nonpremixed flame. Mixture ratios of toluene were 3%, 5%, 10%, and 20%. Senkin code for 0-D simulation and oppdif code for 1-D simulation based on CHEMKIN III were utilized. 0-D results by senkin showed that concentrations of methyl radicals and benzene were increased with increasing toluene mixture ratio. This implied that the mixing of toluene in pure ethylene diffusion flame produces more PAHs and soot than those of pure ethylene flame. 1-D result of 10 % toluene reaction by oppdif code showed that production rate for H radical was a crucial factor for benzene formation. These results imply that methyl radical, benzene and H radical play a important role on soot formation in diffusion flames.

• Journal of the Korean Chemical Society
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• v.27 no.5
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• pp.320-329
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• 1983

Effect of alkyl substitution on stabilization of $\alpha$-aminomethyl radicals, $CH_2NH_2$, has been investigated using MINDO/3-RHF method. Stabilization energies obtained from total energy of radicals indicated that the alkyl substitution decreases radical stability, which is in agreement with the ab initio MO results of Goddard but is contrary to trend shown by experimental results. It was also found that conformations of radicals were different from ab initio results. When, however, approximate account of electron correlation was made in the estimation of stabilization energies of radicals by assuming a proportionality between coulomb correlation and one center exchange integral, the order of radical stability was shown to agree to that found experimentally. It was therefore concluded that the main cause of discrepancy between theoretical and experimental order of stability of alkylsubstituted radicals is the failure of accounting electron correlation energies in the theoretical estimation.