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        검색결과 87

        61.
        2014.01 KCI 등재 서비스 종료(열람 제한)
        Analyzing results of exhaust gas of solid fuel burning are investigated with measuring position in a pilot scale MILD(Moderate and Intense Low oxygen Dilution) combustor using high temperature exhaust gas recirculation. Flue gas hasbeen measured at exit of combustion chamber and stack, especially. Oxygen concentration measured at stack is higherand carbon dioxide concentration is lower than that measured at exit of combustion chamber, because air flows into theflue gas from the post-treatment facilities, such as gas cooler and bag filter, due to negative pressure caused by inducedblower. Low carbon dioxide concentration can cause an error which estimates higher air ratio than actual air flow rateneeded for complete combustion. Average calculated concentration of measured nitric oxide and carbon monoxide forreference concentration of 6% oxygen have no notable difference with measuring position. But, time resolution of thedata measured at exit of combustion chamber is better than that measured at stack. It is confirmed that MILD combustionof solid fuel of pulverized coal using high temperature exhaust gas recirculation can reduce dramatically nitric oxideemission.
        63.
        2013.06 KCI 등재 서비스 종료(열람 제한)
        The effect on the antioxidant activity and Nitric Oxide activity production inhibitory activity of Taraxacum has not been known. Therefore, phenolics and flavonoid contents were investigated from the ethanol extracts of five different Taraxacum species. The results showed that, among the five Taraxacum, T. hallaisanensis contains the highest total phenolic and flavonoid contents. When the antioxidant activity was measured by DPPH, ABTS+ and reducing power activity, the free radical scavenging activity of T. hallaisanensis was also the highest among five Taraxacum species. However, measurement by CCK-8 assay in Raw264.7 cells indicated that the extracts of Taraxacum species have no effect on cell viability. Moreover, we also investigated the effect of Taraxacum species on NO scavenging activity in lipopolysaccharide (LPS)-stimulated Raw264.7 cells. The results clearly showed that Taraxacum species inhibited NO production, and the inhibitory effect of T. hallaisanensis was the strongest. The above results suggested that Taraxacum species affected the antioxidant and NO scavenging activity, and among the five species, antioxidant and NO scavenging activity assay of T. hallaisanensis was significantly higher than those of other four Taraxacum species. Therefore, T. hallaisanensis could be used as a potential drug with anti-oxidant and anti-inflammatory effect.
        66.
        2013.01 KCI 등재 서비스 종료(열람 제한)
        MILD (Moderate and Intense Low oxygen Dilution) combustion using high temperature exhaust gas recirculation is applied to solid fuels of dried sewage sludge and pulverized coal combustion to investigate the effect of reduction of NOx emission in a pilot scale combustor. High temperature exhaust gas recirculation is accomplished by entraining high temperature exhaust gas to air jets at just exit of the combustion chamber without a heat exchanger. High temperature exhaust gas recirculation makes the solid fuel flame stable and extremely uniform color and uniform temperature distribution. NOx concentration at the combustor exit was 62% and 40% less in the high temperature exhaust recirculation MILD combustion compared with the conventional combustion using air jet only for sewage sludge and pulverized coal respectively.
        67.
        2012.10 KCI 등재 서비스 종료(열람 제한)
        This study was carried out to investigate the antibacterial activity against pathogens of acne and the anti-inflammatory effect of 75% ethanol extract and its fractions from the leaves of Prunus sargentii. In the antibacterial activity by the disc diffusion assay, the extract showed the highest effect against Propionibacterium acnes, Staphylococcus aureus and Staphylococcus epidermidis in 5 mg/disc. However, the ethyl acetate fraction showed the highest antibacterial activity in 1 mg/disc. On the other hand, the hexane and chloroform fraction showed strong nitric oxide (NO) production inhibitory effect in lipopolysaccharide (LPS)-stimulated Raw 264.7 cell. In the cell viability of Raw 264.7 by MTT assay, the extract and all fractions were exhibited normal viabilities as nontoxic result. Consequently, the extract from the leaves of P. sargentii and its ethyl acetate fraction could be applicable to functional materials for antibacterial activity related fields. Moreover, the hexane and chloroform fraction could be applicable to candidate materials as anti-inflammatory agent.
        68.
        2012.07 KCI 등재 서비스 종료(열람 제한)
        In the present study, MILD (Moderate and Intense Low oxygen Dilution) combustion technology is adopted as one of the most effective tool for reduction of NOx emission in solid fuel combustion. We tried to achieve MILD combustion using the high temperature exhaust recirculation without any heat exchanger for preheating air. High temperature exhaust recirculation is accomplished by entraining the high temperature exhaust gas to air jets at just exit of the combustion chamber. This high temperature exhaust recirculation could recirculate heat and inert exhaust gas simultaneously. MILD combustion using the recirculation of the high temperature exhaust gas is experimented to investigate the effect of low NOx emission for the recycled solid fuel of the dried sewage sludge and pulverized coal. NOx emission could be reduced drastically by using this advanced combustion technique. Maximum 68% and 57% of NOx reduction was achieved for sewage sludge and pulverized coal respectively, in the high temperature exhaust recirculation MILD combustion compared with the conventional combustion using air jet only. This type of MILD combustion makes the apparent flames of both solid fuels extremely uniform without high temperature flamelet.
        69.
        2012.02 KCI 등재 서비스 종료(열람 제한)
        본 연구는 우엉추출물의 항염증효과를 측정하였다. 인간 유래 폐상피세포 A549를 이용하여 염증반응을 유발하고 유지시키는데 중요한 역할을 나타낸다고 알려진 ICAM-1의 억제적 조절 효과를 평가하였으며, 염증매개인자로 알려진 NO와 이의 생성에 영향을 미치는 iNOS의 발현조절에서도 억제효과가 있음을 확인하였다. 또한, 우엉추출물이 인간각질형성세포주의 세포증식에 효과가 있음을 나타내었다. 본 연구에서 사용되는 폐상피세포는 호흡기질환의 천식 등의 알러지 및 만성염증연구에 주로 활용되고 있으며, 각질형성세포는 아토피 피부염의 만성 염증반응에서 주요하게 확인하는 요소이다. 따라서 본 연구결과에서 나타난 우엉추출물의 항염증 효과는 다양한 염증반응에서도 특히, 알러지 및 아토피 피부염 질환을 더욱 악화시키는 만성 염증에 있어서 우엉추출물이 유용한 소재로 사용될 수 있음을 시사한다고 할 수 있다.
        70.
        2011.12 KCI 등재 서비스 종료(열람 제한)
        The protective effect of nitric oxide (NO) on the antioxidant system under paraquat(PQ) stress was investigated in leaves of 8-week-old lettuce (Lactuca sativa L.) plants. PQ stress caused a decrease of leaf growth including leaf length, width and weight. Application of NO donor, sodium nitroprusside (SNP), significantly alleviated PQ stress induced growth suppression. SNP permitted the survival of more green leaf tissue preventing chlorophyll content reduction and of higher quantum yield for photosystem Ⅱ than in non-treated controls under PQ exposure, suggesting that NO has protective effect on chloroplast membrane in lettuce leaves. Flavonoids and anthocyanin were significantly accumulated in the leaves upon PQ exposure. However, the rapid increase of these compounds was alleviated in the SNP treated leaves. PQ treatment resulted in lipid peroxidation and induced accumulation of hydrogen peroxide (H2O2) in the leaves, while SNP prevented PQ induced increase in malondialdehyde (MDA) and H2O2. These results demonstrate that SNP serves as an antioxidant agent able to scavenge H2O2 to protect plant cells from oxidative damage. The activities of two antioxidant enzymes that scavenge reactive oxygen species, superoxide dismutase (SOD) and catalase (CAT) in lettuce leaves in the presence of NO donor under PQ stress were higher than those under PQ stress alone. Application of 2-(4-carboxyphenyl)-4, 4, 5, 5-tetramethylimidazoline-1-oxyl-3- oxide (PTIO), a specific NO scavenger, to the lettuce leaves arrested SNP mediated protective effect on leaf growth, photosynthetic pigment and antioxidant systems. However, PTIO had little effect on lettuce leaves under PQ stress compared with that of PQ stress alone. The obtained data suggest that the damage caused by PQ stress is in part due to increased generation of active oxygen by maintaining increased antioxidant enzyme activities and SNP protects plants from oxidative stress. From these results it is suggested that NO might act as a signal in activating active oxygen scavenging system that protects plants from oxidative damage induced by PQ stress and thus confer PQ tolerance.
        71.
        2011.10 KCI 등재 서비스 종료(열람 제한)
        In this study, we investigated on antioxidative activity and nitric oxide production inhibitory activity of various solvent extracts of Lespedeza bicolor. The total polyphenol content of the methanol extract was 192.6 mg/g and flavonoid content of the acetone extract was 40.6 mg/g, as the highest content. In DPPH radical scavenging ability, SC50 values of the ethanol and methanol extract were exhibited 0.69mg/ml and 0.89mg/ml, respectively. However, in nitric oxide(NO) scavenging ability, SC50 values of the acetone was exhibited 0.72mg/ml as the highest activity. Moreover, the acetone extract showed strong NO production inhibitory effect in lipopolysaccharide(LPS)-stimulated Raw 264.7 cell. In the cytotoxicity measurement by MTT assay, the extracts were exhibited Raw 264.7 cell viabilities of 92.57~129.04% as nontoxic result in concentration of 65~650μg/ml. As a result, the acetone extract of L. bicolor could be applicable to functional materials for anti-inflammatory related fields.
        72.
        2011.10 KCI 등재 서비스 종료(열람 제한)
        The study was conducted to investigate functional materials as skin whitening and anti-inflammatory agent from Taraxacum officinale and Taraxacum coreanum. The total polyphenol and flavonoid content in the ethanol extract of Taraxacum officinale were found to be 64.07mg/g and 32.46mg/g, respectively. In tyrosinase inhibitory activity, the hot water extract of Taraxacum coreanum was higher than the other extracts. However, in nitric oxide (NO) scavenging ability, the ethanol extract of Taraxacum coreanum was higher than the other extracts. the ethanol extract of Taraxacum coreanum showed strong NO production inhibitory effect in lipopolysaccharide (LPS)-stimulated Raw 264.7 cell. In the cell viability measurement by MTT assay and the lactate dehydrogenase (LDH) assay against L929 cell, the extracts were exhibited fine cell viabilities and normal LDH release levels as nontoxic result in sample concentration of 250~1000μg/ml. As a result, the ethanol extract and the hot water extract of Taraxacum coreanum could be applicable to functional materials for anti-inflammatory and skin whitening related fields, respectively.
        74.
        2011.02 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        본 연구에서는 도라지 분말을 유기용매로 추출한 후 도라지의 추출물과 분획물들에 의한 세포 내 활성산소종 및 glutathione (GSH)를 측정하여 항산화효과를 검토하였고 NO 생성 저해 효과를 알아보았다. 세포 내 활성산소종 생성억제 실험에서 건조 도라지의 A+M 및 MeOH 추출물과 추출물을 n-hexane, 85% aq. MeOH, n-BuOH, water로 다시 추출하여 얻어진 각각의 분획물들을 농도별로 HT1080 세포에 처리하였을 때
        75.
        2010.12 KCI 등재 서비스 종료(열람 제한)
        The effect of nitric oxide (NO) on antioxidant system and protective mechanism against oxidative stress under UV-B radiation was investigated in leaves of maize (Zea mays L.) seedlings during 3 days growth period. UV-B irradiation caused a decrease of leaf biomass including leaf length, width and weight during growth. Application of NO donor, sodium nitroprusside (SNP), significantly alleviated UV-B stress induced growth suppression. NO donor permitted the survival of more green leaf tissue preventing chlorophyll content reduction and of higher quantum yield for photosystem Ⅱ than in non-treated controls under UV-B stress, suggesting that NO has protective effect on chloroplast membrane in maize leaves. Flavonoids and anthocyanin, UV-B absorbing compounds, were significantly accumulated in the maize leaves upon UV-B exposure. Moreover, the increase of these compounds was intensified in the NO treated seedlings. UV-B treatment resulted in lipid peroxidation and induced accumulation of hydrogen peroxide (H2O2) in maize leaves, while NO donor prevented UV-B induced increase in the contents of malondialdehyde (MDA) and H2O2. These results demonstrate that NO serves as antioxidant agent able to scavenge H2O2 to protect plant cells from oxidative damage. The activities of two antioxidant enzymes that scavenge reactive oxygen species, catalase (CAT) and ascorbate peroxidase (APX) in maize leaves in the presence of NO donor under UV-B stress were higher than those under UV-B stress alone. Application of 2-(4-carboxyphenyl)-4, 4, 5, 5-tetramethylimidazoline-1-oxyl-3- oxide (PTIO), a specific NO scavenger, to the maize leaves arrested NO donor mediated protective effect on leaf growth, photosynthetic pigment and free radical scavenging activity. However, PTIO had little effect on maize leaves under UV-B stress compared with that of UV-B stress alone. Nω -nitro-L-arginine (LNNA), an inhibitor of nitric oxide synthase (NOS), significantly increased H2O2 and MDA accumulation and decreased antioxidant enzyme activities in maize leaves under UV-B stress. This demonstrates that NOS inhibitor LNNA has opposite effects on oxidative resistance. From these results it is suggested that NO might act as a signal in activating active oxygen scavenging system that protects plants from oxidative stress induced by UV-B radiation and thus confer UV-B tolerance.
        76.
        2009.06 KCI 등재 서비스 종료(열람 제한)
        A variety of herbs and plants have been traditionally used in oriental folk medicine for the treatment of inflammatory diseases. In our attempt to search for anti-inflammatory agents from natural products, we investigated 64 methanol extracts from 42 medicinal plants belonging to 10 families which were evaluated for inhibitory activities of NO production in lipopolysaccharide (LPS)-stimulated macrophage RAW 264.7 cells. Among them, 16 extracts exhibited inhibitory activities of NO production (IC50 values ranging from 59.6 to 94.7 μg/ml). Only the extract from aerial parts of Hosta lancifolia (H. lancifolia) did not exert cytotoxic effects at the concentrations tested. The extract from H. lancifolia decreased the mRNA and protein levels of inducible nitric oxide synthase (iNOS) and pro-inflammatory cytokines in activated macrophage RAW 264.7 cells in dose-dependent manner. The results suggest that the extract may contain bioactive compounds that suppress expression of pro-inflammatory cytokines, which may prove beneficial with regard to the development of natural agents for prevention and treatment of inflammatory diseases.
        77.
        2008.10 KCI 등재 서비스 종료(열람 제한)
        To search for immunoactive natural products exerting anti-inflammatory activity, we have evaluated the effects on the water extracts of Artemisia princeps Pampanini (APP) on lipopolysaccharide-induced nitric oxide (NO), tumor necrosis factor-α (TNF-α), and prostaglandin E2 (PGE2) production by RAW 264.7 macrophage cell line. Our data indicate that this extract is a potent inhibitor of NO production and it also significantly decreased PGE2 and TNF-α production. Consistent with these results, the protein and mRNA expression level of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) was inhibited by water extracts of APP in a dose-dependent manner. These results suggest that APP may exert anti-inflammatory and analgesic effects possibly by suppressing the inducible NO synthase and COX-2 expressions.
        78.
        2007.12 KCI 등재 서비스 종료(열람 제한)
        Curcumin, a polyphenolic antioxidant purified from turmeric, has been known to possess various biological activities such as anti-oxidative, anti-inflammatory and anti-cancer effects. In this study, we have explored anti-inflammatory effect of curcumin using Gram (-) bacterium-derived endotoxin (lipopolysaccharide: LPS) and macrophage cell line RAW264.7. Curcumin suppressed NO production in LPS-activated RAW264.7 cells in a dose-dependent manner, Curcumin also blocked the activation of NF-kB but not AP-1 according to luciferase assay. Furthermore, this compound suppressed the phosphorylation of a series of intracellular signaling components such as Src, JAK-2, Akt, IKK and IkBα under LPS stimulation in a time dependent manner, Therefore, our data suggest that curcumin was able to protect the host from Gram(-) bacterial-infection-mediated inflammatory symptoms.
        79.
        2007.10 KCI 등재 서비스 종료(열람 제한)
        To search for immunoactive natural products exerting anti-inflammatory activity, we have evaluated the effects of the ethanol extracts of Rubus coreanus Miq. (ERC) on lipopolysaccharide-induced nitric oxide (NO), tumor necrosis factor-α (TNF-α), and Interferon-γ (IFN-γ) production by RAW 264.7 macrophage cell line. Our data indicate that this extract is a potent inhibitor of NO production and it also significantly decreased IFN-γ and TNF-α production. Consistent with these results, the protein level of inducible Nitric Oxide Synthase (iNOS) and cyclooxygenase-2 (COX-2) was inhibited by ethanol extracts of ERC in a dose-dependent manner. These results suggest that ERC may exert anti-inflammatory and analgesic effects possibly by suppressing the inducible NO synthase and COX-2 expressions.
        80.
        2007.10 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        태국산과 베트남산의 용안육 원료 및 그 발효물의 전자공여능, 일산화질소(NO) 생성효과, 인체암 세포주인 자궁경부암세포(HeLa) 및 간암세포(HepG2)의 항암활성 효과를 조사하였다. 원료 용안육의 총 유기산은 태국산 용안육(473.49 mg/g)이 베트남산(148.48 mg/g) 용안육에 비하여 3.2배 높은 함량을 나타내었고, 전체 유기산의 각각 89.2%와 86.8%를 나타내었으며, 주요 유기산은 formic acid와 malic acid
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