• Journal of Korean Society for Atmospheric Environment
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• v.15 no.5
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• pp.667-676
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• 1999

The roles of ceria on three-way catalyst is to improve the noble metal dispersion and thermal stability of support ${\gamma}$-$Al_2O_3$. And, ceria has a oxygen storage capacity(OSC) under fuel rich/lean conditions to improve the operating windows of NOx, THC and CO conversion. However, ceria has weak thermal stability under high temperature due to the crystallite growth. So that, the OSC of ceria is decreased, and then the conversions of NOx, THC and CO is decreased. One way of enhancing the thermal stability and NOx, THC and CO conversion Pd-only catalyst is to improve as well as its thermal stability and oxygen storage capacity of the ceria. Especially, the appropriate mixing ratios of bulk and stabilized ceria are very important for designing principles of Pd-only three-way catalysts. In this paper, we discussed the thermal properties of stabilizedand unstabilized (bulk) ceria, and the oxygen storage capacity (OSC) of catalysts, and found the correlation between activity and the OSC of Pd-only catalysts with various different mixing ratios of bulk and stabilized ceria. Finally, we propose the design principles to improve the thermal stability of washcoated Pd-only catalysts.

• Journal of Korean Society of Forest Science
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• v.95 no.2
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• pp.209-215
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• 2006

We investigated antioxidant capacity in leaves of 14 coniferous trees under field conditions. We focused on understanding the species characteristics on antioxidant systems and screening the coniferous tree species with the best antioxidant systems using their characteristics. The antioxidant capacity of 14 coniferous trees was divided into three groups. First group was Thuja orientalis and Chamaecyparis obtusa and those species had the highest content of ${\beta}$-carotene and xanthophyll. Second group, C. obtusa and Juniperus chinensis, used antioxidant enzymes to mitigate stress. C. obtusa represented high activity at superoxide dismutase (SOD), glutathione reductase (GR), and peroxidase (POD), and J. chinensis exhibited high activity at SOD, POD, catalase (CAT). Third group employed antioxidant such as ascorbic acid and ${\alpha}$-tocopherol. The antioxidant content of T. orientalis was the highest while that of Pinus parviflora and C. obtusa were the lowest. Few species belonged in three groups simultaneously, and most species belonged in at least one or two groups. In summary, we proposed that C. obtusa and T. orientalis had the highest antioxidant capacity while P. parviflora and P. desiflora for. multicalus had the lowest antioxidant capacity.

• Food Science and Biotechnology
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• v.18 no.5
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• pp.1055-1062
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• 2009

This study was conducted to investigate whether dietary chlorella intake could have an effect on antioxidative capacity in rats oxidatively stressed with cadmium (Cd). Sprague-Dawley rats fed dietary chlorella (0, 5, and 10%) for 4 weeks after induction of oxidative stress by exposing to Cd (200 ppm) for 8 weeks. After the oxidative stress applied, plasma and liver malondialdehyde concentrations and xanthine oxidase activities were decreased in 5% chlorella fed group compared to chlorella free group. Although liver heme oxygenase-1 protein expression was not affected by chlorella, the enzyme activity was improved in 5% chlorella fed group. Erythrocyte superoxide dismutase activity and hepatic metallothionein concentration were increased in 5% chlorella fed group. However, 10% chlorella intake had no effect on the improvement of oxidative stress-related enzymes and proteins. These findings suggest that, after induction of oxidative stress with Cd, 5% chlorella intake might improve antioxidative capacity against oxidative stress.

• Education of Primary School Mathematics
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• v.18 no.3
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• pp.175-190
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• 2015

This study investigated the effect of team project activity for game making on the elementary mathematically gifted students' community care and organizational management capacity. 7 mathematically gifted students of 4th grade are selected and participated. After 15 hours activities during 2 months of team project on game making, their community care and organizational management capacity were improved. This results suggested that leadership education is possible in mathematics curriculum for mathematics gifted students.

• Preventive Nutrition and Food Science
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• v.4 no.3
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• pp.180-183
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• 1999

Seaweeds is a rich sources of dietary fibers exerting a number of physiological properties. However, the reported dietary fiber contents of seaweeds are not consistent and vary widely. Also. a limited number of studies on the biological effects of specific seaweeds have been reported. In this study, water-holding capacity, viscosity and antixidantive activity of major dietary seaweeds were measured to assess their physiological effects. Results showed that total dietary fiber contents ranged from 28 to 51% of dried weight, and large proportions of dietary fiber were insoluble fibers. Water-holding capacity was highest in sea mustard being 1310% , while laver, sea tangle, and green laver exhibited 943, 854 and 815%, respectively. The viscosity of seaweed samples was 20 to 40 cP in sea mustard and sea tangle, while laver and green laver possessed much lower values. All seaweed samples revealed a weak, albeit significant electron donating ability. Also, lipid peroxidation was reduced by 7 to 18%. However, there was no difference in antioxidative activity among seaweeds and sample concernations used. These results imply that most commonly used seaweeds possibly exert parts of their physiological effects through their water-holding, gel-forming , and/or antioxidative activities.

• Food Science and Biotechnology
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• v.18 no.4
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• pp.867-871
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• 2009

Response surface methodology (RSM) was used for the optimization of antioxidant capacity in gardenia extracts. The antioxidant capacities of gardenia fruit extracts were investigated by ferric reducing ability (FRA) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity (RSA) assays. The optimum extraction parameters for the strongest antioxidant capacity were the ethanol concentration (EtOH) of 48.9%, extraction temperature of $72.9^{\circ}C$, and extraction time of 29.9 min. Analysis of variance (ANOVA) showed that the quadratics of EtOH and extraction temperature had highly significant effect on the antioxidant capacity (p<0.001). The antioxidant capacity was correlated with contents of bioactive components [crocin, geniposide, and total phenolic (TP) compounds] in gardenia extracts and mainly attributed to the content of the TP compounds.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.6
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• pp.1666-1685
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• 2004

This present study was designed to screen medicinal plants for the treatment of brain diseases such as Parkinson's disease or aging. We tested the effects of the water extracts from 38 species medicinal plants on antioxidant capacity, monoamine oxidase B (MAO-B) inhibitory activity, acetylcholinesterase (AChE) inhibition and antiperoxidation activity in vitro. The water extracts from 38 species were tested on their antioxidant activity using radical scavenging effects against ABTS+. The water extract of C. sappan was showed the highest antioxidant capacity, the antioxidant activity at 1 Jig of herbal extract being 0.38mM TE. Lipid peroxidation in brain homogenates induced by NADPH and ADP-Fe/sup 2+/ was strong inhibited by C. sappan and R. palmatum extracts. Among the 38 medicinal plants investigated, R. palmatum showed significant biological activity (antioxidant capacity, MAO-B inhibiory activity, and AChE inhibitory activity). The protective efficacy of R. palmatum water extract on 1-methyl-4­phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced parkinsonism and its possible mechanism were studied in C57BL/6 mice. Treatment of R. palmatum water extract protected biomacromolecules such as lipids from oxidative damage induced by MPTP. The content of MDA in brain tissue was decreased significantly by R. palmatum extract. These results suggest that R. palmatum water extract plays on effective role in attenuating MPTP-induced neurotoxicity in mice. This protective effect of R. palmatum might be estimated the result from the inhibitory activity on monoamine oxidase B and the enhancement of antioxidant activity.

• IMMUNE NETWORK
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• v.4 no.3
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• pp.166-175
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• 2004

Background: Telomerase, a ribonucleoprotein enzyme capable of synthesizing telomeric repeats, attracts attention for its possible role in determining the replicative capacity of normal somatic cells, transformed cells, and cells of the germline lineage. Differently from normal somatic cells with no telomerase activity, normal lymphocytes has been reported to have telomerase activity comparable to that found in transformed cells during development and activation, which substantiate a role in supporting the capacity of lymphocytes for extensive clonal expansion. Methods: Here, in order to define the telomerase regulation in murine T lymphocytes, telomerase activity in cloned murine $CD8^+$ T cells and naive $CD8^+$ T cells isolated from C57BL/6 mice was examined. Next, the regulatory mechanism of telomerase activity at transcriptional and post- translational levels was investigated by determining the expression level of the TERT protein, a key component for telomerase activity. Results: It was demonstrated that telomerase activity was expressed in an inactivated state as well as in an activated state in the murine $CD8^+$ T lymphocytes by using TRAP assay. The increase of telomerase activity was partially dependent on the net increase of TERT expression. Also, telomerase activity was decreased after treatment with protein kinase inhibitors, indicating that telomerase activation was prevented by inhibition of phosphorylation. Conclusion: Therefore, these results suggest that telomerase activity is constitutively expressed in the murine resting T lymphocytes and controlled by both transcriptional regulation and post- ranslational modifications.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.7
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• pp.1053-1062
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• 2011

Reactive oxygen species (ROS), including singlet oxygen (${O_2}^1$), superoxide anion radical ($O_2{\cdot}^-$), hydroxyl radical ($HO{\cdot}$), peroxyl radical ($ROO{\cdot}$), hydrogen peroxide ($H_2O_2$), and hypochlorous (HOCl), are generated as byproducts of normal cellular metabolism. ROS induce damage to many biological molecules, such as lipids, proteins, carbohydrates, and DNA. It is widely believed that some degenerative diseases caused by ROS can be prevented by the high intake of fruits and vegetables due to their antioxidant activities. Recently, research on natural antioxidants has become increasingly active in various fields. Several assays have been developed to measure the total antioxidant capacity of antioxidants in fruits and vegetables in vitro. These assays include those for DPPH radical scavenging activity, SOD-like activity, total polyphenol content, oxygen radical absorbance capacity, reducing power, trolox equivalent antioxidant capacity (ABTS assay), single-cell gel electrophoresis (comet assay), and a cellular antioxidant activity assay. Because different antioxidant compounds may act through different mechanisms in vitro, no single assay can fully evaluate the total antioxidant capacity of foods. Due to the complexity of the composition of foods, it is important to be able to measure antioxidant activity using biologically relevant assays. In this review, recently used assays were selected for extended discussion, including a comparison of the advantages and disadvantages of each assay and their application to fruits and vegetables.

• Journal of Veterinary Clinics
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• v.28 no.2
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• pp.183-189
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• 2011

The objective of this study was to examine the effect of fucoidan on the phagocytic capapcity and oxidative burst activity (OBA) of canine peripheral blood polymorphonuclear cells (PMNs). The phagocytic capacity and OBA of PMNs were evaluated simultaneously by using a flow cytometer. Fucoidan itself did not cause any direct effect on the phagocytic capacity and OBA of PMNs. However, the phagocytic capacity and OBA of PMNs were enhanced by the culture supernatant from PBMCs treated with fucoidan. The phagocytic capacity and OBA of PMNs were also increased by treatment with recombinant canine (rc) tumor necrosis factor (TNF)-${\alpha}$. The ability of the culture supernatant from fucoidan-treated PBMCs to stimulate the phagocytic capacity and OBA of PMNs was inhibited by addition of anti-rc TNF-${\alpha}$ polyclonal antibody (PAb) prior to the culture. The amount of TNF-${\alpha}$ in the culture supematant from PBMCs was shown to increase upon treatment of fucoidan as compared with that of vehicle-treated PBMCs culture supematant. The level of TNF-${\alpha}$ mRNA expression in PBMCs was also up-regulated by the fucoidan treatment. These results suggest that fucoidan has an immunoenhancing effect on the phagocytic capacity and OBA of canine PMNs, which is mainly mediated by TNF-${\alpha}$ released from fucoidan-stimulated PBMCs.