• Fisheries and Aquatic Sciences
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• v.13 no.3
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• pp.216-223
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• 2010

Abalone (Haliotis discus hannai), mostly distributed and maricultured in southwestern coastal areas of South Korea, is recognized as an economically important species in the fishery industry. Abalone intestines are one of the by-products of abalone processing. To investigate abalone intestines as bioactive substances, abalone intestine gastrointestinal digests (AIGIDs) of various molecular weights (MWs) were prepared using in vitro gastrointestinal digestion and an ultrafiltration system, and tested for inhibitory effects against reactive oxygen species (ROS) and oxidative stress in macrophage cells treated with hydrogen peroxide ($H_2O_2$). In our results, among AIGIDs, AIGID-III (MW=5-10 kDa) showed potent inhibitory activities for lipid peroxidation and free radicals. Additionally, the results clearly indicated that AIGID-III treatment could prevent cytotoxic damage of macrophages by $H_2O_2$-induced oxidative stress due to its potent scavenging ability against cellular ROS. These results suggest that AIGIDs may have protective and therapeutic potential for oxidative stress syndromes and immune diseases through ROS inhibition in macrophage cells.

• Journal of the Korean institute of surface engineering
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• v.42 no.3
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• pp.139-144
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• 2009

A microwave plasma torch at the atmospheric pressure by making use of magnetrons operated at the 2.45 GHz and used in a home microwave oven has been developed. This electrodeless torch can be used to various areas, including industrial, environmental and military applications. Although the microwave plasma torch has many applications, we in the present work focused on the microwave plasma torch operated in pure steam and several applications, which may be used in future and right now. For example, a high-temperature steam microwave plasma torch may have a potential application of the hydrocarbon fuel reforming at one atmospheric pressure. Moreover, the radicals including hydrogen, oxygen and hydroxide molecules are abundantly available in the steam torch, dramatically enhancing the reaction speed. Also, the microwave plasma torch can be used as a high-temperature, large-volume plasma burner by injecting hydrocarbon fuels in gas, liquid, and solid into the plasma flame. Finally, we briefly report treatment of soils contaminated with oils, volatile organic compounds, heavy metals, etc., which is an underway research in our group.

• BMB Reports
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• v.37 no.4
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• pp.416-421
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• 2004

The antioxidant activities of NADH and of its analogue, 1,4-dihydro-2,6-dimethyl-3,5-dicarbethoxy-pyridine ($PyH_2$), were evaluated in vitro. NADH was found to be oxidized by the peroxyl radical derived from 2,2-azobis-(2-amidinopropane) dihydrochloride (AAPH) decomposition, in a pH-dependent manner. Both NADH and $PyH_2$ inhibited the peroxidation of egg yolk lecithin (EYL) liposomes, although $PyH_2$ was more effective than NADH when 2,2'-azobis-4-methoxy-2,4-dimethyl-valeronitrile (methoxy-AMVN) was employed to induce EYL liposome peroxidation. The antioxidant activities of NADH and $PyH_2$ were also evaluated by measuring their influences on 1,3-diphenylisobenzofuran (DPBF) fluorescence decay in the presence of peroxyl radicals. NADH and $PyH_2$ were much more effective at inhibiting DPBF quenching in Triton X-100 micelles than in liposomes. These results indicate that NADH can inhibit lipid peroxidation despite being hydrophilic. Nevertheless, membrane penetration is an important factor and limits its antioxidant activity.

• Journal of Ginseng Research
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• v.32 no.2
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• pp.89-98
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• 2008

There are increasing evidences in the literatures on the potential role of ginsenosides in treating cardiovascular diseases. In this article, current information about ginsenosides-mediated vascular relaxation are reviewed. From the published studies using isolated organs, cell culture systems and animal models, ginsenosides are shown to relax blood vessels and improve blood flow through diverse mechanisms, including nitric oxide release by activating eNOS phosphorylation via PI3K/Akt and/or ERK1/2 pathways in endothelial cells, induction of inducible nitric oxide synthase through activation of NF-${\kappa}$B, reducing the intracelluar Ca$^{2+}$ levels by activating Ca$^{2+}$-activated K$^{+}$ channels in vascular smooth muscle cells and reducing platelet aggregation by decreasing thromboxane A$_2$ formation and intracelluar Ca$^{2+}$in platelets. In addition, the relevant clinical trials regarding the effects of ginsenosides on the cardiovascular disease are summarized, particulary focusing on managing hypertension and improving thrombotic disorders. Finally, antagonistic effects of ginsenosides on the prostaglandin H$_2$ receptor and scavenging effects on the generation of oxygen-derived free radicals in spontaneously hypertensive rats (SHR) are discussed.

• Journal of the Korean Ceramic Society
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• v.44 no.7
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• pp.393-402
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• 2007

Polyaluminocarbosilane was synthesized by direct reaction of polydimethylsilane with aluminum(III)-acetylacetonate in the presence of zeolite catalyst. A fraction of higher molecular weight polycarbosilane was formed due to the binding of aluminium acetylacetonate radicals with the polycarbosilane backbone. Small amount of Si-O-Si bond was observed in the as-prepared polyaluminocarbosilane as the result. Polyaluminocarbosilane fiber was obtained through a melt spinning and was pyrolyzed and sintered into SiC fiber from $1200{\sim}2000^{\circ}C$ under a controlled atmosphere. The nucleation and growth of ${\beta}-SiC$ grains between $1400{\sim}1600^{\circ}C$ are accompanied with nano pores formation and residual carbon generation. Above $1800^{\circ}C$, SiC fiber could be sintered to give a fully crystallized ${\beta}-SiC$ with some ${\alpha}-SiC$.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.2
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• pp.123-126
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• 2002

Lipoxygenase might be associated with seed deterioration by catalyzing the incorporation of molecular oxygen into fatty acids and generating free radicals. This study was performed to determine whether seed lipoxygenase activity would alter soybean seed longevity. In this study, germination percentage of lipoxygenase-lacking cultivar Jinpumkong2 (lx1lx1lx2lx2lx3lx3) was lower than that of Taekwangkong (Lx1Lx1Lx2Lx2Lx3Lx3). Segregation ratio for the three lipoxygenase isozymes of the F2-derived from the cross between Taekwangkong and Jinpumkong2 was fitted to 9 (Lx1Lx2Lx3) : 3 (Lx1Lx2lx3) : 3 (lxllx2Lx3) : 1 (lx1lx2lx3), suggesting the tight linkage between the Lx1 and Lx2 loci. Germination percentages varied widely but not differed among lipoxygenase isozyme types of F$_3$ seeds before and after accelerated aging. Seed coat of Jinpumkong2 was damaged severely following accelerated aging, whereas that of Taekwangkong was not. Thus, seed of lipoxygenase-lacking soybean cultivar, Jinpumkong2 showed greater deterioration compared with that of the normal Taekwangkong. However, the presence or absence of lipoxygenase activity had no effect on soybean germination.

• Journal of the Korean Applied Science and Technology
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• v.25 no.2
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• pp.168-174
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• 2008

This study is focused on the antimicrobial activity of cyanobacteria Microcystis aeruginosa by the reduction and oxidation reaction of copper and zinc alloy metal fiber filter. Cu/Zn ion is easily makes radicals with molecular hydroperoxide. Especially, hydroperoxide radical shows strong toxicity to the strains. Plasma membrane causes conformational change when hydroperoxide radical binds to plasma membrane. Elution of copper ion from copper and zinc alloy metal fiber is detected in the cyanobacteria solution as 0.5 ppm, and that of zinc ion is 0 ppm respectively. Zinc ion is figured to form a hydroxide in the cyanobacteria solution and precipitated to form a sludge. The concentration of chlorophyll-a in the cyanobacteria solution was proved to be the index of antimicrobial level of Microcystis aeruginosa.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.7
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• pp.3437-3443
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• 2013

The polymer insulators have been extensively used as an alternate material of ceramic insulators. However, when they are used in practical conditions, there are many problems of decreasing performance and shortening lifetime due to the exposures of degradation factors applied from the outdoor situations. Accordingly, the analysis of polymer degradations has been getting influential too late as one of important subjects for improvements of safety and reliability. Heat, water treatments are arbitrary simulated for finding out the initiations and processes of surface degradation on the polymer surface. Especially, this study is focused on the chemical changes properties. From the analysis of hydrophilic and hydrophobic molecular structures, final modeling of surface degradation is accomplished. We checked the contact angle depending on heat and moisturized accelerated degradation and ran an XPS analysis to check the mechanism change of the surface of the PCB polymer composite. The surface that had a tendency to attract moisture showed a decrease in the contact angle and generated a large amount of carboxyl($-COO^*$) radicals. The hydrophobized surface showed an increase in the contact angle and had a stable chemical composition constituted of the breakaway of oxygen radicals and the formation of double bond by carburization.

• 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 Korean GEO-environmental Society
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• v.12 no.9
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• pp.55-61
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• 2011

This study investigate the use of ultraviolet(UV) light with hydrogen peroxide($H_2O_2$) for Methyl Tert Butyl Ether(MTBE) degradation in photolysis reactor. The process in general demands the generation of OH radicals in solution at the presence of UV light. These radicals can then attack the MTBE molecule and it is finally destroyed or converted into a simple harmless compound. The MTBE removal by photolysis were mathematically described as the independent variables such as irradiation intensity, initial concentration of MTBE and $H_2O_2$/MTBE ratio, and these were modeled by the use of response surface methodology(RSM). These experiments were carried out as a Box-Behnken Design(BBD) consisting of 15 experiments. Regression analysis term of Analysis of Variance(ANOVA) shows significantly p-value(p<0.05) and high coefficients for determination values($R^2$=94.60%) that allow satisfactory prediction of second-order regression model. And Canonical analysis yields the stationery point for response, with the estimate ridge of maximum responses and optimal conditions for Y(MTBE removal efficiency, %) are $x_1$=25.75 W of irradiation intensity, $x_2$=7.69 mg/L of MTBE concentration and $x_3$=11.04 of $H_2O_2$/MTBE molecular ratio, respectively. This study clearly shows that RSM is available tool for optimizing the operating conditions to maximize MTBE removal.