• 대한기계학회논문집B
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• 제29권2호
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• pp.263-270
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• 2005

An experimental study was performed to investigate the effects of partially premixing, varying the equivalence ratios from $0.79{\sim}{\infty}$, on NOx emissions and chemiluminescence of excited $OH^{\ast},\;CH^{ast}\;C_2^{\ast}$ radicals in laminar partially premixed flames. the signal from the electronically excited state of $OH^{\ast},\;CH^{ast}\;C_2^{\ast}$ was detected through a band pass filter with a photo multiplier tube, which are processed to the intensity ratio ($C_2^{\ast}/CH^{\ast},\;C_2^{\ast}/OH^{\ast},\;and\;CH^{\ast}/OH^{\ast}$) to reveal the correlation with local equivalence ratio. And measurements of NOx emission were made to investigate the relationship between visible flame appearance, chemiluminescence, and EINOX. The results demonstrated that (1) the flames at ${\phi}<1.59$ exhibited classical double flame structure, at ${\phi}>4.76$, the flames exhibited diffusion flame structure, and the intermediate flames at $1.59<{\phi}<4.76$ was a merged flame, (2) the $OH^{\ast}$ peak was located inside the $CH^{\ast}\;and\;C_2^{\ast}$ radical for all measured conditions and the emission intensity ratio of $C_2^{\ast}/CH^{\ast}\;and\;C_2^{\ast}/OH^{\ast}$ were identified as good marker for local equivalence ratio over a range of ${\phi}=0.79{\sim}1.2\;and\;CH^{\ast}/OH^{\ast}\;is\;0.79<{\phi}<1.9$. However, it was difficult to predict the equivalence ratio in partially premixed flames using this system for ${\phi}>2.38$, (3) the minimum NOX emission index (EINOx) is obtained for a equivalence ratio of 3.19 in the intermediate flames.

• 한국지반환경공학회 논문집
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• 제13권3호
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• pp.5-11
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• 2012

본 연구의 목표는 전자빔 공정을 적용하여 Triclosan의 제거효율 및 독성평가를 하는 것이다. 이 실험에서는 전자빔 선량과 Triclosan의 초기 농도에 따른 저감 효율 및 스캐벤저 가스에 따른 무기화의 정도를 알아보았다. 또한 녹조류 중 하나인 Pseudokirohneriella Subcapitata를 이용하여 생물독성과 위해성 평가를 통한 독성저감기술을 시험하였다. 그 결과 Triclosan은 전자빔 조사량이 증가할수록 분해 효율이 향상되었고, 라디칼 스캐벤저 가스에 의한 TOC 제거는 $N_2O$나 $O_2$를 용해시켰을 때 효율이 증가된 것으로 나타났다. 4일(96hrs) 후 독성평가 결과 전자빔 조사 강도의 증가에 따라 독성 영향이 저감되는 것을 알 수 있었다.

• 한국식품영양학회지
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• 제30권5호
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• pp.853-859
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• 2017

This study was conducted in an effort to investigate the effect of Maillard reaction products (MRPs) on enzymatic browning of burdock and their anti-oxidant activity. The MRPs were prepared by heating glucose and amino acids at $90^{\circ}C$, which served to produce a strong inhibitory effect on burdock polyphenol oxidase. As the reaction time of the solution containing glucose and amino acid increased at $90^{\circ}C$, the production of MRPs increased and intensity of the brown color deepened. When MRPs were prepared by heating at $90^{\circ}C$ for five hours, the absorbance of MRPs from glucose and lysine was 6.44, while those of glucose and glycine was 1.95. The MRPs synthesized from the glucose and lysine also reduced the pH of MRPs from 5.60 to 4.51, but those from glucose and glycine decreased slightly from 5.57 to 5.33. The Michealis-Menten constant value ($K_m$) of burdock PPO with pyrocatechol as a substrate was 16.0 mM, and MRPs were a non-competitive inhibitor against burdock PPO. The anti-oxidant activity of MRPs was measured by evaluating its radical scavenging activities of DPPH radicals, ABTS radicals and reducing power. The color intensity of MRPs produced by lysine and glucose were deeper than that produced by glucose and glycine. It was also found that MRPs produced from glucose and lysine exhibited stronger anti-oxidant properties than those produced by glucose and glycine.

• 한국식품과학회지
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• 제45권6호
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• pp.770-776
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• 2013

본 연구에서는 호박잎 추출물의 총 폴리페놀 함량, 총 플라보노이드 함량, radical 소거활성 등과 같은 항산화성과, 암세포 증식억제 활성, 사멸유도 활성, 부착억제 활성 등과 같은 항암성을 in vitro 수준에서 검증하였다. 호박잎의 총 폴리페놀 함량은 263.4 mg gallic acid equivalent/100 g, 총 플라보노이드 함량은 73.6 mg quercetin equivalent/100 g으로 측정되었다. 호박잎 추출물은 300 ${\mu}g/mL$ 농도에서 69.4%의 ABTS radical 소거 활성이 있었는데, 이는 호박잎 추출물과 같은 농도에서의 L-ascorbic acid 활성(94.5%)의 73.4%에 해당되는 수준이었다. 한편 호박잎 추출물은 37.5, 75, 150 ${\mu}g/mL$ 농도에서 HCT116 대장암 세포와 H1299 폐암 세포의 증식을 60.6-87.9% 억제하는 농도 의존적 활성이 있었으며 이는 부분적으로 apoptosis를 유도하기 때문인 것으로 생각된다. 또한 호박잎 추출물은 150 ${\mu}g/mL$ 농도에서 HCT116 세포와 H1299 세포의 부착을 16.8-28.4% 억제하는 활성이 있었다. 이상의 결과를 통하여 호박잎 추출물은 in vitro 수준에서 항산화성 및 항암성을 가지는 것으로 생각되며, 이러한 연구 결과는 향후 관련 작용기전을 규명하기 위한 기초 자료로 이용될 수 있을 것으로 기대된다.

• Elastomers and Composites
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• 제40권3호
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• pp.188-195
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• 2005

본 연구에서는 카본 블랙을 오존 처리 후, 표면의 물리 화학적 변화와 표면 작용기 변화를 조사하였다. 표면의 물리 화학적 변화는 원소 분석, PH, tint strength, DBP, $N_2SA$, IA를 통하여 분석하였고, 표면 작용기의 변화는 금속 수산화물과 표면의 산, 염기 반응을 통하여 조사하였다. 산화 전 후 입자의 구조, 크기, 표면적의 변화는 거의 없었으나, 오존 처리 시간이 길어짐에 따라 산소의 함량이 증가하고 그에 따라 pH는 감소하다가 정체되는 양상을 보였다. 금속 수산화물 $NaHCO_3,\;Na_2CO_3,\;NaOH,\;NaOC_2H_5$을 사용하여 표면의 카르복실기, 락톤기, 하이드록실기, 카르보닐기를 각각 정량하였다. 산화 전에는 소량의 카르보닐기만이 표면에 존재하는 것으로 측정되었으나, 오존처리 시간이 길어짐에 따라 카르복실기와 카르보닐기의 양이 서서히 증가하다가 포화 상태에 이르렀다. 락톤기와 하이드록실기는 산화 전 후 거의 표면에 존재하지 않는 것으로 나타났다. 이러한 실험 결과는 기존의 에틸렌과 오존 반응 메커니즘에 의해 알려진 실험 결과들과 유사하다. 오존 산화 후에 카본 블랙은 AIBN을 처리하면 무게가 증가하였으며 ESR 분석을 통한 자유 라디칼은 약간 감소하였다. 머캅토 작용기를 가진 유기 화합물과 반응시킨 카본블랙은 자유 라디칼의 피크가 거의 다 감소하였다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제33권1호
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• pp.11-19
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• 2007

This study was to evaluate the expression of vascular endothelial growth factor receptors (VEGFRs) in tumor and stromal cells of tougue squamous cell carcinoma (SCC). We also wanted to characterize the differences, from the angiogenic aspect, between cancer-associated stromal cells and non-malignant stromal cells. Paraffin-embedded tumor specimens from eleven patients with tongue SCCs were studied. Immunohistochemical staining for VEGFR-1,-2, and -3 was performed on the tumor cells, stromal fibroblasts and tumor-associated macrophages of the specimens. The expression of all 3 receptors was detected in the tumor cells themselves of the biopsy specimens. All 3 receptors were also expressed on stromal cells, except that VEGFR-2 was not expressed in stromal fibroblasts. In radical excision specimens, the staining intensity for VEGFR-1, -2 in the tumor cells and VEGFR-1,-3 in the tumor-associated macrophages was significantly lower than that in the biopsy specimens (P < 0.05). By using the general marker of fibroblast and macrophage, 5B5 and CD68, respectively, we performed double immunofluorescence staining for 5B5 and each VEGFR in the stromal fibroblasts and for CD68 and each VEGFR in the tumor-associated macrophages of the radical excision specimens. We used 4 cases of fibroma and 4 cases of chronic inflammation tissue as the controls. It was found that only each marker was expressed in the control group, however, 5B5/VEGFR-1 and 5B5/VEGFR-3 in the stromal fibroblasts, and CD68/VEGFR-1 and CD68/VEGFR-3 in the tumor-associated macrophages were double stained in the radical excision specimens. Although our study used small number of specimens, the results of our study showed that in tongue SCC, in association with the angiogenesis, the stromal cells showed the activated phenotype and this was different from the nonmalignant stromal cells.

• 생약학회지
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• 제50권4호
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• pp.299-304
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• 2019

In order to research the anti-oxidative activity of methanol extract of Phellinus baumii Pilat (Hymenochaetaceae), Caenorhabditis elegans model system was used. Ethyl acetate soluble fraction of the methanol extract showed the most potent DPPH radical scavenging activity. The ethyl acetate fraction was measured on its activities of superoxide dismutase (SOD), catalase, and oxidative stress tolerance with reactive oxygen species (ROS) level in C. elegans. Furthermore, to see if regulation of stress-response gene is responsible for the increased stress tolerance of C. elegans which treated by the ethyl acetate fraction, we checked SOD-3 expression using a transgenic strain. Consequently, the ethyl acetate fraction of P. baumii increased SOD and the catalase activities in a dose-dependent manner in C. elegans, reduced ROS accumulation dose-dependently. Besides, the ethyl acetate fraction-treated CF1553 worms showed higher SOD-3::GFP intensity than the control worms.

• 대한기계학회논문집B
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• 제26권10호
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• pp.1348-1354
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• 2002

We investigate the flame behavior and spatial distribution of OH, PAHs and soot in a confined buoyant diffusion flame with decrease of the coflowing air flow rate. Direct photographs and Schlieren images represent that flame is Ally occupied by blue flame and becomes unstable, which is partially detached to the fuel nozzle tip in a near extinction flame under extremely reduced oxidizer condition. Laser induced fluorescence profiles clearly shows that OH is still generated in near-extinction flame, although intensity becomes weak with decreasing air flow rate. But soot scattering image cannot be seen any more in an oxidizer deficient ambience and simultaneously the PAHs are widely distributed downstream. These results are due to that a decrease of oxygen concentration in the combustion chamber leads to a temperature drop of flame, as a consequence, to a delay in soot growth and to a expanding of the PAHs, as soot precursors.

• 생약학회지
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• 제48권3호
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• pp.219-225
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• 2017

We investigated the anti-oxidative effect of the blueberry duke (Vaccinium corymbosum L., Ericaceae) ethanol extract in Caenorhabditis elegans model. The ethanol extract of blueberry duke showed relatively significant DPPH radical scavenging and superoxide quenching activities. To prove antioxidant activity of the extract, we checked the activities of superoxide dismutase (SOD), catalase, intracellular ROS, and oxidative stress tolerance in C. elegans. In addition, to verify if the increased stress tolerance of C. elegans by treating with the extract was due to regulation of stress-response genes, we checked SOD-3 expression using a transgenic strain. As a consequence, the blueberry duke ethanol extract increased SOD and catalase activities of C. elegans, and reduced intracellular ROS accumulation in a dose-dependent manner. Besides, blueberry duke ethanol extract-treated CF1553 worms showed higher SOD-3::GFP intensity.

• 생약학회지
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• 제48권1호
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• pp.63-69
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• 2017

Saururus chinensis (Lour.) Baill. (Saururaceae) has been used as a traditional medicine for the treatment of dysuria, leukorrhea, eczema, jaundice and ascites in Korea, China and Japan. Ethanol extract of S. chinensis was successively partitioned as methylene chloride, ethyl acetate, n-butanol and $H_2O$ soluble fractions. Among those fractions the ethyl acetate soluble fraction showed the most potent DPPH radical scavenging and superoxide quenching activities. To verify antioxidant activities of ethyl acetate fraction, we checked the activities of superoxide dismutase (SOD) and catalase, and intracellular ROS level and oxidative stress tolerance in Caenorhabditis elegans. Furthermore, to see if increased stress tolerance of worms by treating of ethyl acetate fraction was due to regulation of stress-response gene, we quantified SOD-3 expression using transgenic strain. Consequently, ethyl acetate fraction elevated SOD and catalase activities of C. elegans, and reduced intracellular ROS accumulation in a dose-dependent manner. Moreover, ethyl acetate fraction-treated CF1553 worms exhibited significantly higher SOD-3::GFP intensity.