• Polymer(Korea)
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• v.28 no.6
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• pp.551-555
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• 2004

Cellulose diacetate (CDA) nanocomposite films were prepared by using various plasticizer and montmorillonite nanofiller in methylene chloride/ethanol (9:1 w/w) mixed solution. The thermal property (T$_{g}$) of prepared CDA films was observed by DSC and T$_{g}$ of the films was decreased with the increase in the plasticizer content. The degree of dispersion of MMT in the CDA film was observed by XRD and mechanical property of CDA film was measured by tensile strength and Young's modulus. When the plasticizer was added into the CDA film upto 30 wt%, the Young's modulus of film was decreased from 1930 MPa to 1131 MPa but was increased from 1731 MPa to 2272 MPa when the MMT was added into the film upto 7 wt%. The mechanical properties of CDA films were decreased by addition of plasticizer but strengthened by the incorporation of MMT.

• Food Science and Preservation
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• v.12 no.6
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• pp.624-630
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• 2005

Plantain was extracted with ethanol and fractionated systemically with n-hexane, chloroform, ethylacetate, n-butanol and water to study inhibitory effect on cholesterol synthesis in vitro. To screen the effect, inhibitory activities on 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase obtained from Saccharomyces cerevisiae were examined using the five fractions of Plantain. The HMG-CoA reductase activity was inhibited most by ehylacetate fraction among the fractions, although the all five fractions had the effect To see the hypocholesterolemic effect of the ethylacetate fraction of Plantanin (PAE) in vivo, male Sprague-Dawley rats were received 5 types of diets for 6 weeks: normal diet group (NOR), high cholesterol diet group($1\%$ cholesterol and $0.25\%$ sodium cholate, CON), normal diet and PAE 70 mg/kg administered group(S1), high cholesterol diet and PAE 140 mg/kg administrated group(S2), and high cholesterol diet and PAE 140 mg/kg administered group(S3). Body weight gains of the CON were significantly increased compared to those of S1, S2 and S3. Activities of serum AST and ALT were tended to be increased in CON compared with NOR and reduced by the PAE administration. Concentrations of serum total cholesterol, free cholesterol, LDL-cholesterol, triglyceride and the atherogenic index were tended to be decreased in the PAE administered groups compared with the CON. HDL-cholesterol and phospholipid concentrations were significantly decreased in the CON and markedly increased by the PAE administered groups. Taten together, it is suggested that the ethylacetate fraction of Plantanin exerts antiatherosclerotic effect by reducing serum cholesterol concentrations in rats fed high cholesterol diets.

• Korean Chemical Engineering Research
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• v.54 no.5
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• pp.698-705
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• 2016

Butyl acetate is produced from acetic acid and butanol via an esterification reaction in reactive distillation (RD). The product, butyl acetate, has been used as an internal entrainer until now. In this case, butyl acetate and water are removed at the top of column and separated into two different phases (organic and aqueous phases) after condensation, and butyl acetate rich organic phase is refluxed into the RD. This method makes butyl acetate remain high at the reactive zone, leading to lower equilibrium conversion and product yield. We introduced an extraneous entrainer to solve the problem. The extraneous entrainer forms a new azeotrope with water. The proposed process provides lower concentration of butyl acetate in the reactive zone than conventional RD processes using an internal entrainer. We compared the yield and production rate of butyl acetate between the proposed and conventional processes through pilot-scale experiments. Experimental and simulation results showed that the proposed process was more efficient than conventional process using internal entrainer.

• Journal of Life Science
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• v.17 no.10
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• pp.1368-1373
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• 2007

Inhibitory effects of several solvent fractions from soybean on mutagenicity using Salmonella typhimurium TA 100 in Ames test and growth of human cancer cells (AGS gastric adenocarcinoma, Hep 3B hepatocellular cancinoma and HT-29 colon cancer cells) were studied. The treatment of dichloromethane and ethylacetate fractions (2.5 mg/assay) extracted from soybean to Ames test system inhibited aflatoxin $B_1\;(AFB_1)$ induced mutagenicity by 83%, 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 67%) among solvent extracts, although the inhibitory effect was not stronger compared with $AFB_1$ induced mutagenicity. In sulforhodamine B (SRB) assay, the treatment of ethylacetate fraction (2 mg/assay) significantly inhibited the growth of AGS, Hep 3B and HT-29 cancer cells by 66%, 73% and 77%, respectively, followed with the intermediate and dichloromethane fractions. These results indicated that soybean fraction extracted with ethylacetate had higher inhibitory effects on $AFB_1$ and MNNG in Ames test and growth inhibition activity to human cancer cells was appeared, suggesting that soybean fraction extracted with ethylacetate may contain the biologically active compounds.

• Microbiology and Biotechnology Letters
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• v.41 no.3
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• pp.358-366
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• 2013

The aim of this study was to evaluate the antimicrobial activities of Glycyrrhiza uralensis and Glycyrrhiza glabra extracts with various countries of origin. Three samples of licorice with various origins (Korea, China, and Uzbekistan) were evaluated for their antimicrobial activities against six skin microflora. The bioassay applied for determining the antimicrobial effects included the disc diffusion assay, minimum inhibitory concentration, and challenge test. The ethyl acetate fractions of G. uralensis and G. glabra extracts showed significant antimicrobial activities against two gram-positive (Bacillus subtilis, Propionibacterium acnes) and two gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria. These samples had much more intensive antimicrobial activities than synthetic preservatives on B. subtilis, P. acnes, and P. aeruginosa, especially. Korean licorice showed the highest antimicrobial activity amongst the samples tested. In view of the observed inhibitory features of these G. uralensis and G. glabra extracts, it is suggested that they could be used as natural antiseptics against bacterial contamination in cosmetics and foods, instead of the common synthetic preservatives currently employed.

• Proceedings of the Membrane Society of Korea Conference
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• 1992.04a
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• pp.7-8
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• 1992

역삼투막에 이용되고 있는 고분자물질은 셀루로오스 아세테이트(CA)를 비롯하여 방향족 폴리아마이드가 주로 이용되고 있으며, 최근에는 폴리설펀막의 지지층 위에 계면중합법을 응용한 복합막이 주류를 이루고 있다. 여기서는 가장 많이 이용되고 있는 셀루로오스아세테이트를 이용한 역삼투 투과 특성에 관하여 연구하였다.

• Journal of the Korean Chemical Society
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• v.47 no.6
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• pp.667-670
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• 2003

• Journal of the Korean Chemical Society
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• v.54 no.2
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• pp.181-182
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• 2010

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2007.11a
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• pp.37-38
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• 2007

• Polymer(Korea)
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• v.28 no.2
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• pp.135-142
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• 2004

Poly(vinyl acetate) (PVAc) prepared by emulsion polymerization has broad applications for additives such as paint binder, adhesive for wood and paper due to its low glass transition temperature which help to plasticize substrate resins. Since emulsion polymerization has a disadvantage that surfactant and ionic initiator degrade properties of the product polymer, poly(vinyl acetate-co-butyl acrylate) (VVc-BA) was synthesized using potassium persulfate as catalyst and poly(vinyl alcohol) (PVA) as protective colloid to prevent the degradation. The copolymer latex product was internally plasticized and has enhanced colloid stability, adhesion, tensile strength and elongation. During VAc-BA emulsion polymerization, no coagulation and complete conversion occur with the reactant mixture of 0.7wt% potassium persulfate, 15wt% poly(vinyl alcohol) (PVA-217), and the balanced monomer that the weight ratio of vinyl acetate to butyl acrylate is 19. As the concentrations of PVA increase, the copolymerization becomes faster and polymer particles are more stable, resulting in enhanced mechanical stability of the VAc-BA copolymer. However, the size of the polymer particles decreases with increasing PVA contents. Properties of the VAc-BA copolymer, such as minimum film formation temperature, glass transition temperature, surface morphology, molecular weight and molecular weight distribution, tensile strength and elongation, were characterized using differential scanning calorimeter, transmission electron microscope and other instruments.