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        검색결과 493

        461.
        2013.01 KCI 등재 서비스 종료(열람 제한)
        Simulated waste-derived synthesis gas has been tested for hydrogen production through water gas shift (WGS) reaction in the temperature range of 240oC ~ 400oC over supported Pt catalysts prepared by an incipient wetness impregnation method. MG30, MgO, ZrO2, Al2O3 and CeO2 were employed as supports for WGS reaction in this study. 1 wt.% Pt/ CeO2 catalyst exhibited the highest CO conversion as well as 100% CO2 selectivity. This is due to easier reducibility of Pt/CeO2 and high oxygen mobility and oxygen storage capacitiy of CeO2. Pt/CeO2 catalyst can be a promising catalyst for WGS reaction from waste-derived synthesis gas.
        462.
        2012.11 KCI 등재 서비스 종료(열람 제한)
        Odor from sewage treatment plants have the potential to cause significant annoyance and to impact the amenity. In this study, odor emission characteristics at unit process of 48 sewage treatment facilities in 39 plants were evaluated using composite odor concentration and hydrogen sulfide (H2S) concentration. The values of composite odor concentration (geometry mean) and H2S concentration (median) for sludge treatment processes are higher than those for the other treatment processes. The composite odor concentration and H2S concentration are distributed over a wide area in each process. Composite odor concentration (dilution ratio) was found to have the significant correlation with H2S concentration (p=0.000<0.05). The H2S concentration accounted for 67.1% of composite odor concentration.
        468.
        2010.04 KCI 등재 서비스 종료(열람 제한)
        활성산소의 하나인 과산화수소(hydrogen peroxide, H2O2)에 대한 세포독성과 이에 대한 연꽃수술(Nelumbo nucifera stamen, NNS)추출물의 항산화효과 및 멜라닌화에 미치는 영향을 알아보기 위하여 세포부착율 (cell adhesion activity, CAA)을 비롯한 티로시나제활성저해능 및 총멜라닌합성량을 분석하였다. 본 실험 결과 hydrogen peroxide(H2O2)는 배양 인체피부흑색종세포 (SK-MEL-3)의 CAA를 유의하게 감소시킴으로서 세포독성효과를 나타냈다. 이에 대하여 NNS추출물은 H2O2의 산화적 손상에 의하여 감소된 CAA를 유의하게 증가시킴으로서 항산화효과를 나타냈다. 한편, H2O2에 대한 NNS추출물의 멜라닌화에 대한 영향에 있어서 NNS추출물은 H2O2에 의하여 활성화된 티로시나제활성과 총멜라닌합성량을 감소시킴으로서 멜라닌화에 대하여 억제효과를 나타냈다. 이상의 결과로 부터 H2O2는 배양 인체피부흑색종세포에 고독성을 나타냈으며 NNS와 같은 식물추출물은 H2O2와 같은 활성산소에 의한 산화적 손상 및 멜라닌화를 방어하는데 효과적인 것으로 나타났다.
        469.
        2009.12 KCI 등재 서비스 종료(열람 제한)
        산소자유라디칼의 하나인 hydrogen peroxide(H2O2)에 대한 세포독성과 이에 대한 페놀화합물의 일종인 gallic acid의 영향을 cell adhesion activity(CAA)를 비롯한 DPPH-radical scavenging activity, lactate dehydrogenase(LDH) activity에 의하여 분석하였다. 본 실험에서 H2O2는 배양 인체피부흑색종세포(SK-MEL-3)에 처리한 농도에 의존적으로 유의한 세포부착율의 감소를 나타냈으며 또한 고독성 효과를 보였다. 한편, H2O2의 산화적 손상에 대한 gallic acid의 방어효과를 조사하기 위하여 세포부착율과 LDH 활성을 조사하였다. 그 결과 gallic acid는 H2O2에 의하여 감소된 세포부착율을 유의하게 증가시킨 반면, LDH 활성은 유의한 감소를 보임으로서 항산화효과를 나타냈다. 더욱이 gallic acid는 DPPH-radical scavenging activity의 분석에서 유의한 자유라디칼 소거능을 보였다. 이상의 결과로 부터 H2O2는 배양 인체피부흑색종세포에 고독성을 나타냈으며 gallic acid와 같은 페놀화합물은 H2O2와 같은 산화적 손상을 방어하는데 효과적이었다.
        470.
        2009.02 KCI 등재 서비스 종료(열람 제한)
        Vitis amurensis (VA; Vitaceae) has long been used in oriental herbal medicine. It has been reported that roots and seeds of VA have anti-inflammatory and antioxidant effects. In the present study, the protective effect of ethanol extract from stems and leaves of VA on hydrogen peroxide (H2O2) (100 μm)-induced neuronal cell damage was examined in primary cultured rat cortical neurons. VA (10-100 μg/ml) concentration-dependently inhibited H2O2-induced apoptotic neuronal cell death measured by 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) assay and Hoechst 33342 staining. VA inhibited H2O2-induced elevation of intracellular Ca2+ concentration ([Ca2+]i) and generation of reactive oxygen species (ROS), which were measured by fluorescent dyes. Pretreatment of VA also prevented glutamate release into medium induced by 100 μm H2O2, which was measured by HPLC. These results suggest that VA showed a neuroprotective effect on H2O2-induced neuronal cell death by interfering with H2O2-induced elevation of [Ca2+]i, glutamate release, and ROS generation. This has a significant meaning of finding a new pharmacological activity of stems and leaves of VA in the CNS.
        471.
        2008.09 KCI 등재 서비스 종료(열람 제한)
        본 연구는 활성산소종의 일종인 hydrogen peroxide(H2O2)에 대한 산수유(Cornus fructus, CF)추출물의 영향을 배양 NIH3T3 섬유모세포를 재료로 세포부착능과 항산화 측면에서 조사하였다. 그 결과 H2O2는 농도 의존적으로 배양 세포의 세포부착능을 감소하였으며 XTT50값이 100 uM이하로 나타남으로서 Borenfreund와 Puerner(1984)의 독성판정기준에 따라 고독성인 것으로 나타났다. 한편, H2O2의 산화적 손상에 대한 CF추출물의 세포부착능에 대한 영향에 있어서 CF추출물의 처리는 H2O2의 산화적 손상으로 감소된 세포부착능을 유의하게 증가시켰다. 또한, H2O2의 산화적 손상에 의하여 유발된 지질과산화에 의한 막손상에 대하여 CF추출물의 처리는 H2O2에 의하여 증가된 LDH 활성을 유의하게 감소시켰다. 또한, CF추출물은 농도 의존적으로 superoxide dismutase(SOD) 유사활성을 나타냈다. 이상의 결과로 부터 H2O2와 같은 활성산소종은 배양 NIH3T3 섬유모세포에 대하여 세포독성을 보였으며 또한 CF추출물은 H2O2에 의한 산화적 손상을 방어함으로서 항산화 효과를 나타냈다.
        473.
        2008.04 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        Bacillus subtilis subsp. subtilis는 녹조류인 매생이에서 분리되는 총 생균주 중에서 90%를 차지하고 있다. Bacillus subtilis subsp. subtilis에 대한 항미생물 활성을 50 ppm 수준에서 과산화수소와 NaOCl의 각각의 처리가 전해수 (50 ppm) 보다 유의적 수준에서 높았다. 매생이를 50 ppm의 과산화수소, NaOCl 그리고 전해수로 처리한 후 에서 30일간 일반포장 또는 진공포장에 의한
        474.
        2007.12 KCI 등재 서비스 종료(열람 제한)
        Dried leaves from Cedrela sinensis A. Juss. (CS), have been observed to possess various pharmacological activity and contain various antioxidant constituents. The protective effect of ethanol extract of CS on hydrogen peroxide (H2O2)-induced neurotoxicity was examined using primary cultured rat cortical neurons in the present study. Exposure of cultured neurons to 100 μM H2O2 caused a significant neuronal death as assessed by a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) assay and Hoechst 33342 staining. The addition of CS, over a concentration range of 10 to 50μg/ml, concentration-dependently prevented the H2O2-induced neuronal apoptotic death. CS (50μg/ml) significantly inhibited H2O2-induced elevation of the cytosolic Ca2+ concentration ([Ca2+]c), which was measured by a fluorescent dye, Fluo-4 AM. CS (30 and 50μg/ml) inhibited glutamate release and generation of reactive oxygen species (ROS) induced by 100μM H2O2. These results suggest that CS may mitigate the H2O2-induced neurotoxiciy by interfering with the increase of [Ca2+]c, and then inhibiting glutamate release and generation of ROS in cultured neurons.
        475.
        2007.11 KCI 등재 서비스 종료(열람 제한)
        Plant peroxidases (PODs) have been shown to reduce hydrogen peroxide (H2O2) in the presence of an electron donor. Extracellular POD also induce H2O2 production, and can perform a significant function in responses to environmental stresses. We previously described the isolation of 10 POD cDNA clones from cell cultures of sweetpotato (Ipomoea batatas). Among them, the expression of the swpa4 gene was profoundly induced by a variety of stresses. In this study, transgenic tobacco (Nicotiana tabacum) plants overexpressing the swpa4 gene under the control of the CaMV 35S promoter were generated in order to assess the function of swpa4. Both transient expression analysis with the swpa4-GFP fusion protein and POD activity assays in the apoplastic washing fluid revealed that the swpa4 protein is secreted into the apoplastic space. The transgenic plants also evidenced a significantly enhanced tolerance to a variety of abiotic and biotic stresses. These plants harbored increased lignin and phenolic content, and H2O2 was also generated under normal conditions. Furthermore, they manifested increased expression levels of a variety of apoplastic acidic pathogenesis-related (PR) genes following enhanced H2O2 production. These results suggest that the expression of swpa4 in the apoplastic space functions as a positive defense signal in the H2O2-regulated stress response signaling pathway.
        478.
        2007.04 KCI 등재 서비스 종료(열람 제한)
        The protective effect of ethanol extract of Korean mistletoe (KM; Viscum album coloratum) on hydrogen peroxide (H2O2)-induced neurotoxicity was examined in primary cultured rat cortical neurons. H2O2 reduced viability of cortical neurons in a concentration-dependent manner. The addition of KM, over a concentration range of 10 to 100 μg/ml, concentration-dependently prevented the H2O2(100 μM)-induced neuronal cell death, as assessed by a 3-[4,5-dimethylthiazol-2-yl]-2,5-di-phenyl-tetrazolium bromide (MTT) assay and Hoechst 33342 staining. KM significantly inhibited H2O2-induced elevation of the cytosolic Ca2+ concentration ([Ca2+]c), which was measured by a fluorescent dye, fluo-4 AM. KM inhibited glutamate release into medium and generation of reactive oxygen species (ROS) induced by H2O2. These results suggest that KM may mitigate the H2O2-induced neurotoxiciy by interfering with the increase of [Ca2+]c, and inhibiting glutamate release and generation of ROS in cultured neurons.
        479.
        2006.12 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        항산화능이 있는 곤충 추출물을 검색하기 위하여 초고속 스크리닝 시스템을 이용하여 몇 가지의 hit를 검색하였다. 메뚜기를 각 용매별 (DW, DMSO, Ethanol, Methanol)로 추출하여 추출물을 제조하였으며, 이들 추출물의 항산화능 검색과 함께 과산화 수소의 세포 독성에 대한 보호 효과에 대하여 조사하였다. 그 결과, 항산화 관련 실험인 DPPH, FRAP assay의 경우 실험에 사용된 모든 메뚜기류의 모든 에탄올과 메탄을 추출물에서
        480.
        2006.04 KCI 등재 서비스 종료(열람 제한)
        Paeoniae radix has been widely used for its anti-allergic, anti-inflammatory and analgesic effects, and demonstrated to have anticonvulsant, memory enhancing and anxiolytic activities. The present study was performed to examine the protective effect of methanol extract of Paeoniae radix (PR) from Paeoniae Japonica Miyabe et Takeda (Paeoniaceae) on hydrogen peroxide (H2O2)-induced neurotoxicity using cultured rat cerebral cortical neuron. H2O2 produced a concentration-dependent reduction of neuronal viability, PR, over a concentration range of 10 to 100 μg/ml showed concentration-dependent decrease of the H2O2(100 μM)-induced neuronal cell death, as assessed by a 3-[4,5-dimethylthiazol-2-yl]-2,5-di-phenyl-tetrazolium bromide assay and the number of apoptotic nuclei, evidenced by Hoechst 33342 staining. PR (100 μg/ml inhibited 100 μM H2O2-induced elevation of the cytosolic Ca2+ concentration ([Ca2+]c), which was measured by a fluorescent dye, flue-4 AM. PR (50 μg/ml inhibited glutamate release into medium induced by 100 μM H2O2, which was measured by HPLC, and generation of reactive oxygen species (ROS). These results suggest that PR may mitigate the H2O2-induced neurotoxiciy by interfering with the increase of [Ca2+]c, and then inhibiting glutamate release and generation of ROS in cultured neurons.