• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.2
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• pp.143-147
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• 2000

The effects of alginate extracting conditions from sea tangle and the effects of film preparation conditions on the physical properties of the alginate film were investigated by measuring ester compounds permeability. The higher concentration of sodium carbonate solution as extracting solvent made the higher ethyl acetate permeability of alginate film, but extracting time showed little efficacy of alginate film permeability. The higher concentration of sorbitol as a plasticizer showed higher ethyl acetate permeability of alginate film, Adding various plasticizers, the ethyl acetate permeability of algiante films was increased in order as follow : sorbitol, glycerol and polyethylene glycol. Ester compounds haying the lower molecular weight showed the higher permeability. And the higher temperature made the ethyl acetate permeability of algiante film to be high.

• Fire Science and Engineering
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• v.25 no.5
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• pp.69-75
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• 2011

It was performed to test the combustive properties of low density polyethylene and ethylene vinyl acetate (LDPE-EVA) composite by the addition of magnesium hydroxide. Flame retardant of natural magnesium hydroxide was added to the mixture of LDPE-EVA in 40 to 80 wt% concentration. The composite was compounded to prepare specimen for combustive analysis by cone calorimeter (ISO 5660-1). Comparing with virgin LDPE-EVA, the specimens including the magnesium hydroxide had lower flashover possibility. It is supposed that the combustive properties in the composites decreased due to the endothermic decomposition of magnesium hydroxide. The specimens with magnesium hydroxide showed both the lower total heat release rate (THR) and lower CO production rate than those of virgin polymer. As the magnesium hydroxide content increases, the total smoke release (THR) and smoke extinction area (SEA) decreased.

• Journal of Life Science
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• v.23 no.3
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• pp.383-388
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• 2013

This study was performed to determine the whitening effect of several solvent fractions of Diospyros kaki extracts. Fractions from ethanol extracts of D. kaki were prepared by a systematic fractionation procedure using hexane, ethyl acetate, butanol, and $H_2O$. The ethyl acetate fractions were used to evaluate the inhibitory effects on tyrosinase activity and melanin synthesis in B16F10 melanoma cells. Ethyl acetate fractions suppressed the expression of tyrosinase, TRP-1 and TRP-2 in B16F10 melanoma cells. These results showed that ethyl acetate fractions of D. kaki could be developed as a skin whitening material in cosmetics.

• Food Science and Preservation
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• v.5 no.3
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• pp.281-285
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• 1998

Methanol extract and various solvent fractions from Moutan Cortex were tested for their antimicrobial activities, free radical scavenging activities and antioxidative activities, and phenolic compounds in ethylacetate fraction were analyzed by GC and HPLC. In the antimicrobial activities test, the ethylacetate fraction of methanol extract showed stronger than other fractions. The antimirobial activities were more effective against Gram positive bacteria than Gram negative bacteria. Minimum inhibitory concentration(MIC) of ethylacetate fraction showed 156-1250$\mu\textrm{g}$/ml against Cram positive bacteria and 2500-5000$\mu\textrm{g}$/mg against Gram negative bacteria. The free radical scavenging activities and antioxidative activities using linoleic acid were higher in ethylacetate fraction. The antioxidative activity of ethylacetate fraction was similar to ${\alpha}$-tocopherol. The 3 major phenolic compounds were analyzed by GC and HPLC and these content were determined. The content of p-hydroxybenzoic acid, methyl gallate and gallic acid were 1.35%, 14.61% and 4.01%, respectively.

• Polymer(Korea)
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• v.28 no.2
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• pp.128-134
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• 2004

Cellulose nanoparticles loaded with vitamin I acetate were prepared by modified spantaneous emulsification solvent diffusion method. After cellulose derivatives were dissolved in mixed acetone/ethanol organic solvent with vitamin E acetate, cellulose nanoparticle suspensions were dispersed in poly(oxyethylene sorbitane monooleate) solution using ultrasonicator. Particle size and loading amount of vitamin I acetate were measured by particle size analyser and UV-spectrometer, respectively. The stability of nanoparticle was determined by measuring the change of the particle size at room temperature for 30 days and the morphology was observed by SEM. Morphology of cellulose nanoparticles was spherical and particle size was not changed at room temperature for 30 days. The optimum condition for the preparation of cellulose nanoparticles was 1% w/v cellulose nitrate with 8% w/v poly(oxyethylene sorbitane monooleate) solution. It showed that particle size and loading amount of vitamin E acetate was 65nm and 71%, respectively.

• Polymer(Korea)
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• v.38 no.3
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• pp.307-313
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• 2014

The physical properties of functionalized graphene sheet (FGS)/poly(ethylene-co-vinyl acetate) (EVA) was examined with various kinds of EVA, having vinyl acetate (VA) contents in the range of 0 to 40 wt%. The compatibility between FGS and EVA was enhanced as the polar VA content of EVA increased. Thus, the dispersion of FGS in EVA became finer, and the decrease of surface resistivity and the increase of tensile modulus by the added FGS became more effective when the VA content of EVA was high. When the VA content was low, the elongation at break was reduced drastically by added FGS due to the poor adhesion of FGS/EVA interface. The crystallization of EVA was generally retarded by the interaction with dispersed FGS. However, when both the VA content of EVA and the added amount of FGS were low, the crystallization of EVA was enhanced, probably due to the predominant nucleating effect by FGS.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.04a
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• pp.110.1-110
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• 2003

이팝나무(Chionanthus retusus)는 물푸레나무과에 속하는 낙엽교목으로 육도목, 유소수라고도하며 중국이나 일본에서는 잎을 차대용으로 사용한다고 하여 다엽수라고도 부른다. 지사, 건위, 중풍 등의 치료에 효과적이고, 강장제, 해열제, 이뇨제 등으로 사용되었다고 알려져 있는 이팝나무 잎의 생리활성을 검색하여 유용자원으로 활용하기 위한 기초 연구로 메탄을 추출물을 각종 용매를 이용하여 분획한 후 DPPH를 이용한 항산화 활성, 아질산염 소거 및 항균 활성 등의 생리활성에 대한 실험 결과는 다음과 같다. DPPH에 의한 항산화 활성을 측정한 결과 에틸 아세테이트 분획물과 부탄올 분획물에서 가장 높은 활성을 나타내었으며, reducing power의 경우 에틸 아세테이트 분획물에서 그리고 농도가 증가함에 따라 환원력이 증가하는 것으로 나타났다. 아질산염 소거능은 pH가 낮을수록, 농도 의존적으로 그 활성이 높게 나타났다. 항균활성은 에틸 아세테이트 분획물에 대하여 특히, Escherichia coli와 Bacillus cereus 균주에 대해 각각 16 및 18mm 로 높은 항균력을 나타내었다.

• Applied Chemistry for Engineering
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• v.17 no.3
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• pp.291-295
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• 2006

The keto-enol tautomeric equilibrium constant, K, of ethyl acetoacetate in compressed and supercritical carbon dioxide was determined by using FT-IR (Fourier transform infrared) spectroscopy at three different temperatures. In order to investigate the effect of solvent density, the $CO_{2}$ pressure was systematically changed at a constant temperature. As the $CO_{2}$ density is increased, the amount of keto tautomer is increased, causing the K value to decrease. The modified lattice fluid hydrogen bonding theory has been applied to investigate the effect of density on the K.

• Journal of Life Science
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• v.17 no.6 s.86
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• pp.791-797
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• 2007

We studied the inhibitory effect of solvent fractions from doenjang on mutagenicity using Salmonella typhimurium TA100 in Ames test. We also investigated the effect of solvent fractions from doenjang on the growth of tumor cells and the production of interleukin-2 (IL-2). The treatment of dichlorormethane and ethylacetate fractions (2.5 mg/assay) from doenjang to Ames test system inhibited aflatoxin B$_1$ (AFB$_1$) induced mutagenicity by 96% and 97%, respectively, and showed a higher antimutagenic effect than other solvent fractions. In case of N-methyl-N'-nitro-N-nitrosoguamidine (MNNG) induced mutagenicity, the ethylacetate fraction showed the highest inhibitory effect (by 75%) among the other sol-vent fractions, although the inhibitory effect was not stronger compared to AFB$_1$ induced mutagenicity. The treatment of dichloromethane and ethylacetate fractions markedly inhibited the growth of Yac-1 (by 80% and 94%, respectively) and sacroma-180 cancer cells (by 60% and 96%, respectively) after 4 days of incubation at 37${\circ}$C. To elucidate the immunological mechanism of antitumor activity of doenjang, spleen cells of Balb/c mouse were exposed to the dichloromethane and ethyl-acetate fractions for 24 hours at 37${\circ}$C . The culture supernatants following the treatment of djchloromethane and ethylacetate factions to spleen cells increased the production of IL-2. These results indicated that the anticarcinogenic effect of doenjang was mediated by the production of IL-2.

• Microbiology and Biotechnology Letters
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• v.46 no.1
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• pp.18-28
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• 2018

In this study, the antioxidant activities and cytoprotective effects against oxidative stress of Lonicera japonica Thunb. 50% ethanol extract and ethyl acetate fraction were investigated. Using the 1,1-diphenyl-2-picrylhydrazyl assay, the free radical scavenging activity (FSC50) of L. japonica Thunb. 50% ethanol extract and ethyl acetate fraction was determined as 152.00 and $77.25{\mu}g/ml$, respectively. To measure the reactive oxygen species (ROS) scavenging activity, the total antioxidant capacity (OSC50) was determined by using a luminol-dependent chemiluminescence assay. The antioxidant activity of the ethyl acetate fraction ($0.33{\mu}g/ml$) was approximately four times stronger than that of the 50% ethanol extract ($1.12{\mu}g/ml$). The protective effect against $^1O_2$-induced cellular damage of human erythrocytes (${\tau}_{50}$) was 46.0 min at $10{\mu}g/ml$ of the 50% ethanol extract and 52.3 min at $1{\mu}g/ml$ of the ethyl acetate fraction. We also investigated the cytoprotective effects against oxidative stress induced by $H_2O_2$ and the intracellular ROS scavenging activity in response to UVB irradiation and found that the extract and fraction protected human skin cells from damage and reduced ROS. These results confirmed that L. japonica Thunb. was a valuable plant-derived natural antioxidant with potential for development as an antioxidative functional ingredient.