• Korean Journal of Environmental Agriculture
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• v.18 no.3
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• pp.259-264
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• 1999

This experiment was carried out to investigate the changes of antioxidant enzymes activities in soybean leaves, exposed to 0.2ppm of ozone. We have investigated whether Eunhakong and Samnamkong may scavenge ozone induced activated oxygen species by invoking antioxidant enzymes such as ascorbate peroxidase(APOX), glutathione reductase(GR), monodehydroascorbate reductase(MDHAR), dehydroascorbate reductase(DHAR). Ozone exposure preferentially increased APOX, GR and MDHAR activities, whereas that of DHAR only decreased slowly. When soybean plans were fumigated with 0.2ppm of ozone, the levels of ascorbate and reduced glutathione decreased within a few hours. In eunhakong, which has, slightly a strong tolerance to ozone, was found to have higher antioxidants levels than samnamkong. However, there was no remarkable difference two cultivars in the activities of enzymes which protect plant against active oxygen species.

• Journal of Adhesion and Interface
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• v.15 no.1
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• pp.22-30
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• 2014

Self-photoinitiating acrylate (SPIA) which can undergo self-initiation under UV irradiation was synthesized by a Michael addition in the presence of a base catalyst. The SPIA polymerizations were investigated by photo-differential scanning calorimeter (photo-DSC) and surface physical properties such as pendulum hardness and pencil hardness. The results showed that the SPIA can cure upon UV irradiation by itself without a photoinitiator. But we found out that both the curing rate and the conversion were too low for the self-curing reaction of SPIA. In order to improve the SPIA curing properties, we introduced the SPIA/cationic hybrid system and observed the effects of the addition of commercial free radical type monomer and photoinitiator on the curing behaviors. SPIA/cationic hybrid system was the best suitable to improve the SPIA curing properties. The kinetic analysis indicated that the cationic monomer and photoinitiator apparently accelerated the cure reaction and rate of the hybrid SPIA system, mostly due to the synergistic effect of cationic monomer and photoinitiator increasing the mobility of active species and the generation of reactive species (free radical, cation) during the photopolymerization process. The physical properties showed that, unlike typical free radical system, the hybrid systems did not show oxygen inhibition effect because of cationic reaction on the coating surface.

• Journal of the Korean Wood Science and Technology
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• v.7 no.2
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• pp.3-30
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• 1979

Larch ($\underline{Larix}$ $\underline{leptolepis}$ GORDON), one of the major afforestation species in Korea in view of its growing stock and rate of growth, is not favored as a raw material for pulp due to its low yield of pulp and difficulties with bleaching arising from the high content of extractives in wood, and the high heartwood ratio and the active phenolics, respectively. The purpose of this study is to investigate the characteristics of firstly pulping with various additives of cellulose protector for the yield of pulp, and secondly bleaching with oxygen for chlotination-alkali extraction of five stage-sequence to reduce chlorine compounds in bleaching effluents. The kraft cooking liquor for five age groups of larchwood was 18 percent active alkali with 25 percent sulfidity and 5 : 1 liquor-to-wood ratio, and each soda liquor for sap-and heart-wood of the 15-year-old larchwood was 18 percent alkali having one of the following cellulose protectors as the additive; magnesium sulfate ($MgSO_4$, 2.5%), zinc sulfate ($ZnSO_4$, 2.5%), aluminium sulfate ($Al_2(SO_4)_3$, 2.5%), potasium iodide (KI, 2.5%), hydroquinone (HQ, 2.5%), anthraquinone (AQ, 0.1%) and ethylene diamine (EDA, 2.5%). Then each anthraquinone-soda liquor for the determination of suitable cooking condition was the active alkali level of 15, 17 and 19 percent with 1.0, 0.5 and 0.1 percent anthraquinone, respectively. The cooking procedure for the pulps was scheduled to heat to 170$^{\circ}C$ in 90 minutes and to cook 90 minutes at the maximum temperature. The anthraquinone-soda pulps from both heartwood and sapwood of 15-year-old larchwood prepared with 0.5 percent anthraquinone and 18 percent active alkali were bleached in a four-stage sequency of OCED. (O: oxygen bleaching, D: chlorine dioxide bleaching and E: alkali extraction). In the first stage oxygen in atmospheric pressure was applied to a 30 percent consistency of pulp with 0.1 percent magnesium oxide (MgO) and 3, 6, and 9 percent sodium hydroxide on oven dry base, and the bleached results were compared pulps bleached under the conventional CEDED (C: chlorination). The results in the study were summarized as follows: 1. The screened yield of larch kraft pulp did not differ from particular ages to age group, but heartwood ratio, basic density, fiber length and water-extractives contents of wood and the tear factor of the pulp increased with increasing the tree age. The total yield of the pulp decreased. 2. The yield of soda pulp with various chemicals for cellulose protection of the 15-year-old larchwood increased slightly more than that of pure soda pulp and was slightly lower than that of kraft pulp. The influence of cellulose protectors was similar to the yield of pulps from both sapwood and heartwood. The effective protectors among seven additives were KI, $MgSO_4$ and AQ, for which the yields of screened pulp was as high as that of kraft pulp. Considering the additive level of protector, the AQ was the most effective in improving the yield and the quality of pulp. 3. When the amount of AQ increased in soda cooking, the yield and the quality of the pulp increased but rejects in total yield increased with decreasing the amount of active alkali from 19 to 15 percent. The best proportion of the AQ seemed to be 0.5 percent at 17 percent active alkali in anthraquinone-soda pulping. 4. On the bleaching of the AQ-soda pulp at 30 percent consistency with oxygen of atomospheric pressure in the first stage of the ODED sequence, the more caustic soda added, the brighter bleached pulp was obtained, but more lignin-selective bleaching reagent in proportion to the oxygen was necessary to maintain the increased yield with the addition of anthraquinone. 5. In conclusion, the suitable pulping condition for larchwood to improve the yield and quality of the chemical pulp to the level for kraft pulp from conventional process seemed to be. A) the selection of young larchwood to prevent decreasing in yield and quality due to the accumulation extractives in old wood, B) the application of 0.5 percent anthraquinone to the conventional soda cooking of 18 percent active alkali, and followed, C) the bleaching of oxygen in atmospheric pressure on high consistency (30%) with 0.1 percent magnesium oxide in the first stage of the ODED sequence to reduce the content of chlorine compounds in effluent.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.4
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• pp.381-389
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• 2009

Confined spaces are inherently dangerous workplace and many fatal and nonfatal accidents have been reported. Even though these accidents occur in various kinds of confined spaces, there has rarely been reported on the health hazard agent, i.e., the types of gases and their concentration ranges. Therefore in this study, we evaluated several toxic and asphyxiating gas concentrations in various confined spaces. We surveyed 57 manholes, 3 sewage treatment plants, 2 yellow radish manufacturing companies and 7 barges to measure the concentrations of oxygen($O_2$), hydrogen sulfide($H_2S$), carbon monoxide(CO), ammonia($NH_3$). Lower Explosion Limits(LEL) and Volatile Organic Compounds (VOCs). Those four types of confined spaces occupies 56% of accidents during last 9 years in Korea. In 57 manholes, the concentration varied according to the types of manholes; rainfall and sewage, and by location; residential and industrial areas. Sewage manhole in industrial area was evaluated as the most hazardous than other types of manhole like rainfall manholes, residential sewage manholes. The highest $H_2S$ concentration and the lowest $O_2$ concentration at sewage manhole in industrial area were 300 ppm, 8.7% respectively. In 3 sewage treatment plants, $H_2S$ and $NH_3$ concentrations were reached up to the 500 ppm and 200 ppm respectively. Two yellow radish manufacturing companies showed the concentrations of 316 ppm, 505.2 ppm, 90 ppm and 15.7% for $H_2S$, CO, VOCs and $O_2$, respectively. Seven barges showed 15.9%~20.9% oxygen concentration. Gas species and concentration ranges varied by the types and location of confined spaces; CO, $H_2S$, $O_2$ could be hazardous in manhole, especially manhole connected to sewage plants. CO, $H_2S$, LEL, $O_2$, $NH_3$ should be controlled in sludge silo and sluge pumping confined spaces in sewage treatment plant. The activity of lifting out radish from the storage tank was evaluated more hazardous rather than the other activities in yellow radish manufacturing industry. The employers must conduct the survey to identify all possible confined spaces in their local workplace prior to performing the tasks. At the national level to reduce the accidents in the confined spaces, we suggest that systemic approach and active education program including possible hazards, standard operation procedures, ventilation plan, and personal protective equipment in confined spaces should be implemented.

• Applied Biological Chemistry
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• v.34 no.2
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• pp.162-167
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• 1991

In an attempt to explore the mechanistic aspects of chilling injury in plants and their defensive measures against the low temperature stress, the time sequential measurements of pyruvate, superoxide radicals$(O_{\overline{2}})$ and antioxygenic enzymes during whole period of injury-inducing treatment were performed using mostly rice seedlings. Pyruvate was substantialy accumulated in leaf tissues during the exposure period to $5^{\circ}C$ of the seedlings ; the relative extent of the accumulation was increased with increasing time of the cold treatment. When the cold-treated plants were translocated to ambient temperature$({\sim}25^{\circ}C)$, the accumulation started to dissipate, concomitantly accompaning a remarkable increase in the $O_{\overline{2}}$ level of tissues. Superoxide dismutase(SOD) and catalase were also activated during post-chilling period, although they showed a considerable lag time for activation. In contrast, glutathione peroxidase, another antioxygenic enzyme in cells, was not activated at all by preceding cold treatment of plants. The uptake of exogenous $O_{\overline{2}}$ by the roots of rice seedlings resulted in increase in the activities of SOD and catalase in root tissues. The supply of $H_2O_2$ to plan st brought about the activation of catalase in situ, while failing to exert any effect on the activation state of glutathione peroxidase. The results obtained in this work suggest that pyruvate accumulation in cells is the direct cause of the overproduction of $O_{\overline{2}}$ and thereby other toxic activated oxygen species, and that SOD and catalase may play a crucial role in the protection of plant cells against active oxygen-mediated chilling injury.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.1
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• pp.11-20
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• 2014

In this work, the antioxidative effects and active component analysis of Gnaphalium affine D. DON. (G. affine) extracts were investigated. All experiments were performed with 70% ethanol extract, ethyl acetate fraction and aglycone fraction of the G. affine extract. The free radical (1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activity ($FSC_{50}$) of ethyl acetate fraction ($6.15{\mu}g/mL$) of the G. affine was higher than that of (+)-${\alpha}$-tocopherol ($8.89{\mu}g/mL$), which is known as a reference control. Reactive oxygen species (ROS) scavenging activities ($OSC_{50}$) of the 70% ethanol extract ($1.60{\mu}g/mL$), ethyl acetate fraction ($0.075{\mu}g/mL$) and aglycone fraction ($2.28{\mu}g/mL$) of extract of G. affine on ROS generated in $Fe^{3+}$-EDTA/$H_2O_2$ system using the luminol-dependent chemiluminescence assay were much higher than that of L-ascorbic acid ($6.88{\mu}g/mL$). The cellular protective effects of 70% ethanol extract (${\tau}_{50}$ = 52.0 min) and aglycone fraction of the extract (${\tau}_{50}$ = 60.6 min) on the $^1O_2$-induced cellular damage of human erythrocytes were exhibited the higher protective effect than (+)-${\alpha}$-tocopherol (${\tau}_{50}$ = 38.0 min), known as a lipophilic antioxidant. TLC and HPLC were used to analyse active components in the aglycone fraction of the extract. Results showed that luteolin and apigenin were main components. These results suggest that the G. affine extract can be applied to an effective antioxidant in scavenging ROS including radicals.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.38 no.1
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• pp.57-65
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• 2012

In the present study, the antioxidative properties, inhibitory activity on tyrosinase, and active components of Eriobotrya japonica (E. japonica) leaf extract were investigated. The free radical (1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activity ($FSC_{50}$) of extract/fraction of E. japonica leaf was in the order 50 % ethanol extract ($22.625{\mu}g/mL$) < ethyl acetate fraction (6.75) < deglycosylated aglycone fraction (5.06). Reactive oxygen species (ROS) scavenging activities ($OSC_{50}$) of fraction/extracton ROS generated in $Fe^{3+}-EDTA/H_2O_2$ system using the luminol-dependent chemiluminescenceassay were investigated. $OSC_{50}$ of the ethyl acetate fraction, deglycosylated aglycone fraction, and ethanol extract were 0.75, 0.79, and $1.61{\mu}g/mL$, respectively. The cellular protective effects of E. japonica leaf extract on the rose-bengal sensitized photohemolysis of human erythrocytes were investigated. The protective effects of extract/fraction of E. japonica leaf were increased in a in a concentration dependent manner ($5{\sim}50{\mu}g/mL$). Especially, ${\tau}50$ of ethyl acetate fraction at concentrations of $10{\mu}g/mL$ and $50{\mu}g/mL$ showed the most protective effects at 390.8 min and 1471.5 min. The inhibitory effect ($IC_50$) on tyrosinase of E. japonica leaf extracts was higher than arbutin, known as a skin-whitening agent. The order of inhibitory effects was acetate fraction ($75.25{\mu}g/mL$) < 50 % extract (74.1) < deglycosylated aglycone fraction (43.35). TLC of the ethyl acetate fraction showed 7 bands (EJL 1 - EJL 7). HPLC of the aglycone fraction exhibited 2 peaks, kaempferol and quercetin. The amounts of kaempferol and quercetin were 53.7 and 46.3 %. respectively. Therefore, The amounts of kaempferol and its glucoside were a little bit higher than quercetin and its glucoside in E. japonica leaf extract. Accordingly, these findings suggest that extracts/fractions of E. japonica leaf can function as antioxidants in biological systems, especially skin exposed to UV radiation, and protect cellular membranes against ROS. Thus, the extract/fraction of E. japonica leaf may be used in novel functional cosmetics as antioxidants against skin photoaging.

• Journal of Microbiology and Biotechnology
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• v.18 no.9
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• pp.1613-1619
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• 2008

It has been reported that Tat-SOD can be directly transduced into mammalian cells and skin and acts as a potential therapeutic protein in various diseases. To isolate the compound that can enhance the transduction efficiency of Tat-SOD, we screened a number of natural products. 3-O-[$\beta$-D-Glucopyranosyl(1$\rightarrow$4)-$\alpha$-L-arabinopyranosyll-hederagenin (OGAH) was identified as an active component of Fatsia japonica and is known as triterpenoid glycosides (hederagenin saponins). OGAH enhanced the transduction efficiencies of Tat-SOD into HeLa cells and mice skin. The enzymatic activities in the presence of OGAH were markedly increased in vitro and in vivo when compared with the controls. Although the mechanism is not fully understood, we suggest that OGAH, the active component of Fatsia japonica, might change the conformation of the membrane structure and it may be useful as an ingredient in anti-aging cosmetics or as a stimulator of therapeutic proteins that can be used in various disorders related to reactive oxygen species (ROS).

• Proceedings of the Ginseng society Conference
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• 2006.05a
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• pp.57-58
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• 2006

Red ginseng is a classical traditional Chinese medicine. Among Chinese herbs, red ginseng has been considered as one of the tonics. Many studies indicated that red ginseng could enhance immune function of the human body. Red ginseng total saponin, ginsenoside, the most important active constituents identified in red ginseng can protect against myocardial ischaemia damage and protect endothelium against electrolysis-induced free radical injury. Macrophages play a significant role in host defense mechanisms. When activated, they inhibit the growth of a wide variety of tumor cells. The aim of this study was to determine the effects of pure ginsenoside Rb1 on immunostimulatory activity such as murine macrophage phagocytosis and proliferation of splenocytes. Furthermore, we investigated the effects of ginsenoside Rb1 on the production of nitric oxide (NO), reactive oxygen species (ROS) and proinflammatory cytokines (IL-1beta, IL-6, and TNF-alpha) in murine macrophage, RAW 264.7 cells. ROS have emerged as important signaling molecules in the regulation of various cellular processes. Ginsenoside Rb1 significantly increased production of ROS in dose dependent manner. As NO plays an important role in immune function, ginsenoside Rb1 treatment could modulate several aspects of host defense mechanisms due to stimulation. Treatment with ginsenoside Rb1 to macrophages induced the production of NO and proinflammatory cytokines and expression levels of these genes in a dose-dependent manner. Furthermore, incubation of RAW 264.7 cells with ginsenoside Rb1 showed a dose dependent increased phagocytosis activity and lymphocyte proliferation of splenocytes. Therefore, these results suggest that ginsenoside Rb1 has promising potential as a natural medicine for stimulation of the immune system.

• Applied Chemistry for Engineering
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• v.31 no.1
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• pp.108-114
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• 2020

In this study, NH₃-selective catalytic oxidation (SCO) efficiencies according to calcination/reduction conditions were compared when preparing various Ru[1]/TiO₂ catalysts. The Ru[1]/TiO₂ red catalyst had better NH₃ conversion and NH₃ to N₂ conversion than those of Ru[1]/TiO₂ cal. Physico-chemical properties of Ru[1]/TiO₂ catalysts were confirmed by Brunauer Emmett Teller (BET), X-ray diffraction (XRD), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and temperature programmed reduction (H₂-TPR) analyses, and the properties were shown to affect the dispersion and surface adsorption oxygen species (O_β) ratio of the active metal.