• Journal of the Korean Wood Science and Technology
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• v.28 no.3
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• pp.70-77
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• 2000

Among four compounds such as oxyresveratrol, resveratrol, morin and afzelechin isolated from the heartwood of Morns bombycis, oxyresveratrol and resveratrol which belong to stilbenoid indicated high antioxidative and antimicrobial activity, respectively. Based on this result, this experiment was carried out to elucidate the relationship between biological activities of stilbenoids and their chemical structures using two isolated and six synthesized ones prepared by Wittig reaction. Antimicrobial activity of 3,5-dihydroxystilbene(pinosylvin) devoid of hydroxyl group of B-ring was the best among the tested stilbenoids. Antimicrobial activities of the stilbenoids showed negative dependency on the number of hydroxyl groups of B-ring, that is, the fewer number of hydroxyl groups of B-ring, the higher antimicrobial activity. On the other hand, antioxidative activities of the stilbenoids indicated a positive relationship with the number of hydroxyl groups of B-ring. In tetrahydroxystilbenoids, antioxidative activities of the compounds possessing ortho-diphenol structure, 2',3,3',5- and 3,3',4',5-tetrahydroxystilbene, were superior to the others. As a result, it was concluded that resveratrol and oxyresveratrol isolated from the heartwood of M. bombycis had antimicrobial and high antioxidative activities, and these activities of stilbenoids were also dependent on the number and position of hydroxyl groups of B-ring.

• Membrane Journal
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• v.19 no.3
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• pp.228-236
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• 2009

ABA type triblock copolymer of poly(hydroxyl ethyl acrylate )-b-polystyrene-b-poly(hydroxyl ethyl acrylate), i.e. PHEA-b-PS-b-PHEA, was synthesized throughatom transfer radical polymerization (ATRP). This block copolymer was thermally crosslinked with 4,5-imidazole dicarboxylic acid (IDA) via the esterification between the -OH groups of PHEA in block copolymer and the -COOH groups of IDA. Upon doping with ${H_3}{PO_4}$ to form imidazole-${H_3}{PO_4}$ complexes, the proton conductivity of membranes continuously increased with increasing ${H_3}{PO_4}$ content. The PHEA-b-PS-b-PHEA/IDA/${H_3}{PO_4}$ polymer membrane with [HEA]:[IDA]:[${H_3}{PO_4}$]=3:4:4 exhibited a maximum proton conductivity of 0.01 S/cm at $100^{\circ}C$ under anhydrous conditions. Thermal gravimetric analysis (TGA) shows that the PHEA-b-PS-b-PHEA/IDA/${H_3}{PO_4}$ complex membranes were thermally stable up to $350^{\circ}C$, indicating their applicability in fuel cells.

• Applied Chemistry for Engineering
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• v.19 no.5
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• pp.497-503
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• 2008

A variety of techniques has been employed in order to reduce problems caused by the crystallization of paraffin and saturated fatty acid esters in diesel fuel containing biodiesels. Methacrylate copolymers are known as additives which reduce the pour point and cold filtering plugging point (CFPP) of diesel fuels. This paper describes the synthesis, characterization and low temperature properties, having as an initial step the synthesis of the alkyl methacrylate monomers by esterification of methacrylic acid with C12, C18, and C22 fatty alcohols. The copolymerization of these monomers with styrene was then performed, with molar ratios of 30:70, 50:50 and 70:30 for styrene:alkyl methacrylate. All copolymers were characterized by $^1H-NMR$, FT-IR, and gel permeation chromatography (GPC). The poly(styrene-co-alkyl methacrylate)s (PStmSMAn) leads to a large reduction in the pour point and CFPP of poly(styrene-co-alkyl methacrylate) in ultra low sulfur diesel (ULSD) and BD5 with treated 100~5000 ppm of poly(styrene-co-alkyl methacrylate). BD5 fuel containing 5000 ppm of the copolymer (PSt82SMA18) showed a $25^{\circ}C$ and $9^{\circ}C$ reduction in their pour points and CFPP, respectively.

• Journal of Life Science
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• v.17 no.2 s.82
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• pp.230-234
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• 2007

Oxygen is required for many important aerobic cellular reactions, it may undergo electrontransfer reactions, which generate highly reactive membrane-toxic intermediates (reactive oxygen species, ROS), such as hydrogen peroxide, singlet oxygen, superoxide radical, hydroxyl radical, hydroperoxyl radical, hydroxy ion. Various mechanisms are available to protect cells against damage caused by oxidative free radicals, including scavenging enzyme systems such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). This antioxidant defense system is a very complex and finely tuned system consisting of enzymes capable of detoxifying oxygen radicals as well as low molecular weight antioxidants. In addition, repair and turnover processes help to minimize subcellular damage resulting from free radical attack. $H_2O_2$,one of the major ROS, is produced at a high rate as a product of normal aerobic metabolism. The primary cellular enzymatic defense systems against $H_2O_2$ are the glutathione redox cycle and catalase. From Northern blot analysis of total RNAs from cultured cell with $H_2O_2$ treatment, various results were obtained. Expression of Cu/Zn SOD decreased when cell passage increased, but the level of the Cu/Zn SOD was scarcely expressed in 35 passage.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.43 no.2
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• pp.125-135
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• 2017

The purpose of this study is verification of the anti-oxidant effect and anti-inflammatory effect of Eggplant-cheongyeolsodokum composed of 8 herbs (Solanum melongena L., Lonicera japonica Thunb., Glycyrrhiza uralensis Fisch., Ligusticum chuanxiong Hort., Angelica gigas Nakai., Coptis deltoidea C. Y. Cheng et Hsiao., Gardenia jasminoides J. Ellis., Forsythia suspensa Vahl) to confirm the possibilities as useful cosmetic material. We used the modified prescription of 'cheongyeolsodokum' contained in Korean traditional medical book 'Donguibogam' as composition of Eggplant-cheongyeolsodokum and their proportions. Eggplant-cheongyeolsodokum were extracted with hot water, 70% ethanol and then powdered. To confirm anti-oxidant effect, we investigated radical scavenging ability (DPPH, $ABTS^+$, superoxide), superoxide dismutase (SOD)-like activity, total polyphenolic contents. Also to confirm anti-inflammatory effect, we investigated inhibition effect of nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages, and Inhibition effect of the expression of inflammatory-related proteins (iNOS, COX-2) by western blot analysis. As a result, Eggplant-cheongyeolsodokum showed good anti-oxidant and anti-inflammation effects, we suggest that it can be used as an active ingredient for cosmetics.

• Applied Biological Chemistry
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• v.34 no.3
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• pp.287-294
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• 1991

The relationships between the quantitative structure of benzotriazoles and their post-emergence growth inhibiting activity$(pI_{50})$ against Oryzae sativa L. and Echinochloa crus-galli were investigated using a generalized quantitative structure activity relationships (QSAR). According to the QSAR analysis, the free radical parameter $(E_R)$ is a very important factor and the growth inhibiting activity values showed parabolic relation to $E_R$ parameter of para-substituents(X). The activity of (3) was superior to those of (4) and (3b) is selected as the most highly effective compound. The optimal values of $E_R$ parameter of the growth inhibiting activity aganist E.crus-galli are $E_R(3)=0.52\;and\;E_R(4)=0.15$, respectively. From the result of molecular design, the substituents(X) of electron withdrawing properties and $E_R$ parameter of optimal value(0.52) were most desirable for high activity of the benzotriazoles. And in view of this, benzotriazoles may also be effective in blocking the photosynthetic electron transfer.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.8
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• pp.1143-1150
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• 2005

Antioxidative activities of 5 common edible seaweeds in Korea, three brown algae (seaweed fusiforme, sea mustard, sea tangle), one green algae (sea lettuce) and one red algae (laver), were examined. The antioxidative activities of ethanol extracts from these seaweeds were examined by measuring of inhibition rates against iron-induced linoleate peroxidation, DPPH (1,1-diphenyl -2-picrylhydrazyl) radical generation and MDA-BSA (malondialdehyde-bovine serum albumin) conjugation. Sea lettuce ethanol extract showed the strongest anti-oxidative activity among them, especially in inhibition against conjugation of lipid peroxide and protein. Second to sea lettuce, laver and sea tangle ethanol extracts showed high DPPH radical scavenging activity and inhibition against MDA-BSA conjugation. However, seaweed fusiforme and sea mustard ethanol extracts did not show antioxidative activities. Sea mustard contained the highest total flavonoids (11.33 mg/g dry wt) and sea lettuce contained the highest total polyphenol (8.97 mg/g dry wt) among these seaweeds. In addition, there was strong positive correlation between the antioxidative activity and total polyphenol content in these seaweeds, suggesting polyphenol compounds may contribute to antioxidative effect of seaweeds. From these data, it is suggested to consume much of seaweeds such as sea lettuce, laver and sea tangle to prevent age-related chronic diseases, and also develope neutraceutical products using polyphenol rich fraction from sea lettuce.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.10
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• pp.1151-1157
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• 2017

This study examined the immune response of Philippines eel (Anguilla bicolor) to the oral administration of fermented Sparassis crispa stipe extract for 6 weeks. The S. crispa extract fermented with Lactobacillus plantarum showed a higher total phenol content (301.68 ppm) and DPPH radical scavenging activity (63.9%) than those fermented with other strains. Therefore, L. plantarum was selected as a suitable starter culture for the fermentation of S. crispa stipe. The eels were fed a commercial diet supplemented with 1% of fermented S. crispa stipe extract for 6 weeks. The mortality rate of the eels fed the supplemented diet was significantly lower than those of the control after 6 weeks. The lysozyme activity of the serum was increased significantly (12.33 ${\rightarrow}$ 54.66 units) after 6 weeks in the eel fed supplemented diets of fermented S. crispa stipe. The serum of the eel fed the supplemented diet of the S. crispa stipe extract showed higher bactericidal activity. These results suggest that both the S. crispa stipe extract and fermented S. crispa stipe have strong potential to activate the innate immune response of the Philippines eel.

• Membrane Journal
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• v.19 no.4
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• pp.302-309
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• 2009

A block copolymer of polystyrene-b-poly (hydroxyl ethyl methacrylate), PS-b-PHEMA, was synthesized via atom transfer radical polymerization (ATRP) and crosslinked with 4,5-imidazole dicarboxylic acid (IDA) via esterification of the -OH groups of PHEMA in the block copolymer and the -COOH groups of IDA. Upon doping with $H_3PO_4$ to form imidazole-$H_3PO_4$ complexes, the proton conductivity of the membranes continuously increased as the content of $H_3PO_4$ increased. In addition, both the tensile strength and the elongation at break increased with IDA content. A proton conductivity of 0.01 S/cm at $100^{\circ}C$ was obtained for the PS-b-PHEMA/IDA/$H_3PO_4$ membrane with [HEMA]:[IDA]:[$H_3PO_4$] = 3:4:4 under anhydrous conditions. All of the PS-b-PHEMA/IDA/$H_3PO_4$ membranes were thermally stable up to $350^{\circ}C$, as revealed by thermal gravimetric analysis (TGA).

• Membrane Journal
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• v.27 no.6
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• pp.499-505
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• 2017

The increasing number of natural disasters resulting from anthropogenic greenhouse gas emissions has prompted the development of a gas separation membrane. Carbon dioxide ($CO_2$) is the main cause of global warming. Organic polymeric membranes with inherent flexibility are good candidates for use in gas separation membranes and poly(dimethyl siloxane)(PDMS) specifically is a promising material due to its inherently high $CO_2$ diffusivity. In addition, poly(vinyl pyrrolidine)(PVP) is a polymer with high $CO_2$ solubility that could be incorporated into a gas separation membrane. In this study, poly(dimethyl siloxane)-poly(vinyl pyrrolidine)(PDMS-PVP) comb copolymers with different compositions were synthesized under mild conditions via a simple one step free radical polymerization. The copolymerization of PDMS and PVP was characterized by FTIR. The morphology and thermal behavior of the produced polymers were characterized by transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Composite membranes composed of PDMS-PVP on a microporous polysulfone substrate layer were prepared and their $CO_2$ separation properties were subsequently studied. The $CO_2$ permeance and $CO_2/N_2$ selectivity through the PDMS-PVP composite membrane reached 140.6 GPU and 12.0, respectively.