• 대한화장품학회지
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• 제31권4호
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• pp.329-335
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• 2005

노화와 연관하여 설련의 항산화 효과, in vitro MMP 활성 저해능, 자외선 조사에 의해 유도된 MMP-1 발현에 대한 영향을 사람섬유아세포를 이용하여 확인하였다. 설련의 항산화 효과를 알아보기 위하여 DPPH radical과 superoxide anion radical 소거효과를 측정하였다. 그 결과 DPPH radical 소거능의 $IC_{50}$ 값은 $3.89{\mu}g/mL$이고, xanthine/xanthine oxidase에 의한 superoxide anion radical 제거능의 $IC_{50}$ 값은 $67.29{\mu}g/mL$이었다. 설련 $1000{\mu}g/mL$에서 93.27%의 지질과산화 저해효과를 나타내었다. MMP-1의 효소활성 저해 효과는 농도 의존적으로 활성을 억제하였으며, $IC_{50}$ 값은 $97.18{\mu}g/mL$이다. 또한 자외선 조사에 의해 사람 섬유아세포에서 발현되는 MMP-1에 대해 단백질의 양적인 변화는 42.86% 감소되었으며, 설련에 의해 농도 의존적으로 MMP-1 mRNA의 발현량도 감소되었다. 이러한 실험결과를 통하여 설련은 항산화 효과뿐만 아니라 자외선 조사에 의해 유도되는 MMP-1 단백질 발현과 mRNA 유전자 수준에서의 조절이 가능함을 확인하였다. 결론적으로 설련은 항산화와 자외선으로부터 생성되는 MMP-1의 발현을 저해함으로써 노화와 따른 피부를 보호하는 항노화 소재로서의 응용가능성을 확인하였다.

• 한국응용과학기술학회지
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• 제31권2호
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• pp.285-295
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• 2014

Citrus essential oil were extracted from citron peel of cultivated in Gohong (CCP) using environmentally friendly supercritical carbon dioxide method. Antioxidant activity and aroma composition of the essential oils extracted by the SC-$CO_2$ method were evaluated by comparing with those extracted by organic solvent method. Fatty acid composition, DPPH scavenging, and antioxidant activity of the oils obtained by different extraction condition of SC-$CO_2$ method were investigated and their antioxidant activities were compared with commercially available lavender, eucalyptus and tea tree oils. As the results, linoleic acid was most abundantly found from CCP oil extracted by the SC-$CO_2$ method and cis-11,144-eicosadienoic acids was second abundantly found. Radical scavenging ability of DPPH was 98% when the concentration of CCP oil was 50 mg/mL. This scavenging ability increased with the increase of oil concentration. On the other hand, flavonoids content (84 mg/100g) of the CCP oil extracted by the SC-$CO_2$ method was slightly higher than that (75 mg/100g) by hexane extraction. The results, obtained from CCP oil by GC-MS, indicated that, among 66 components, the content of terpenes was 55.8% and limonene was 27.3%.

• 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 Photoscience
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• 제8권2호
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• pp.67-69
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• 2001

Radical cations of DPBEY and PPCB were generated by ${\gamma}$-radiolysis and pulse radiolysis in halogenated solvents. The radical cation PPCB+ shows 505 (shoulder) and 520 nm absorption peaks with 700 ns lifetime in agreement with the laser flash photolysis work and strongly support the exciplex mechanism proposed for the photoreaction of PPCB and dimethylfumarate.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.473-476
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• 2004

This study has investigated radiation degradation of low density polyethylene(LDPE). Samples were irradiated using a $Co^{60}\;\gamma-ray$ and ray up to 800 kGy at a dose rate of 5 kGy/hr in the presence of air atmosphere at room temperature. After irradiation, free radical measurement of LDPE has established by electron spin resonance(ESR). Then, each sample was stored for 2 weeks. ESR measurement showed that free radical concentration(FRC) was increased with radiation dose and changed from alkyl, allyl radical to peroxy radical with time.

• Natural Product Sciences
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• 제10권5호
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• pp.244-247
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• 2004

The inhibitory effects of the leaves of Eucalyptus darylmpleana (Myrtaceae) on the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical was examined. The scavenging effect of the ethyl acetate fraction of Eucalyptus darylmpleana leaves on DPPH radical was stronger than the other fractions, and further purified by silica gel and Sephadex LH-20 column chromatography. 3,4-Dihydroxybenzoic acid, gallic acid, quercetin, quercetin $3-O-{\alpha}-_L-rhamnoside$, quercetin $3-O-{\beta}-_D-glucoside$ and quercetin 3-O-rutinoside were isolated and elucidated by spectroscopic data. Among these components, gallic acid and quercetin $3-O-{\alpha}-_L-rhamnoside$ exhibited potent scavenging activities on DPPH radical with $IC_{50}$ values of 6.02 and $5.54\;{\mu}M$, respectively.

• 한국수소및신에너지학회논문집
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• 제23권5호
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• pp.493-502
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• 2012

Syngas laminar burning velocity measurements were carried out at atmospheric pressure and ambient temperature using the Bunsen flame configuration with nozzle burner as a fundamental study on flame stability of syngas fuel. Representative syngas mixture compositions ($H_2$:CO) such as 25:75%, 50:50% and 75:25% and equivalence ratios from 0.5 to 1.4 have been conducted. Average laminar burning velocities have been determined by the stabilized nozzle burner flames using the angle method, radical surface area method and compared with the data obtained from the other literatures. And the results of each experimental methodologies in the various composition ratios and equivalence ratios were coincided with the result of numerical simulation. Especially, it was confirmed that there was necessary to choice a more accurate measurement methodology even the same static flame method for the various composition ratios of syngas fuel including hydrogen. Also, it was reconfirmed that the laminar burning velocities gradually increased with the increasing of hydrogen content in a fuel mixture.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
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• pp.271.1-271.1
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• 2003

In order to find the new hepatoprotective agents the preliminary screening of 12 prescriptions which have been used for the treatment of hepatic disease in Oriental traditional medicine has been carried out. Both DPPH free radical scavenging and hepatoprotective effect on tacrine-induced cytotoxicity in Hep G2 cells are performed. (omitted)

• 한국연소학회지
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• 제20권3호
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• pp.8-12
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• 2015

The CO reduction characteristics of hot air stream diluted with exhaust gas in a perfectly stirred reactor (PSR) were investigated numerically. The dilution ratio ($\Omega$), inlet temperature ($T_{in}$), and residence time ($\tau$) were considered as parameters to investigate the effects of those on the emission indices for CO and $CO_2$ (EICO and $EICO_2$). The roles of dominant reactions and the production rates of major species were analyzed. It was found from the EICO trend that the supplied CO in the air stream was consumed. The EICO increased negatively with $T_{in}$ at fixed $\tau$ regardless of $\Omega$. However, the magnitude of EICO and minimum inlet temperature for CO reduction showed complicated trend according to the variation of $\tau$. It was identified that the OH radical, generated from the reactions, $O_2+H{\leftrightarrow}O+OH$ and $2OH{\leftrightarrow}H+H_2O$, affected the CO reduction by the reaction, $CO+OH{\leftrightarrow}H+CO_2$. However, the CO emission ratio increased at sufficiently high inlet temperature range due to the thermal dissociation of $CO_2$.

• 한국식품저장유통학회지
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• 제16권6호
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• pp.915-923
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• 2009

감태 효소 가수분해물과 제주특별자치도에서 생산된 신선한 고등어를 이용하여 건강 기능성이 부여된 고품질 간고등어를 제조할 목적으로 감태 효소 가수분해물의 적정 처리 조건에 대하여 살펴보았다. 감태 효소 가수분해물 처리유무 및 처리농도에 관계없이 간고등어의 일반성분, 염도, 대장균, pH, 휘발성염기질소, histamine 및 과산화물값은 5% 유의수준에서 차이가 인정되지 않았다. 하지만, DPPH free radical, hydroxyl radical, hydrogen peroxide, and alkyl radical와 같은 radical 소거 활성은 감태 효소 가수분해물의 처리농도가 높을수록 우수하였다. 이와 같은 결과로부터 신선한 제주특별자치도 연안산 간고등어와 감태 효소 가수 분해물을 이용하여 건강 기능성이 부여된 고품질 간고등어를 제조하고자 할 때 최적 감태 효소 가수분해물의 농도는 2%로 판단되었다. 이와 같이 신선한 고등어에 2% 감태 효소 가수분해물을 처리하여 제조한 간고등어는 시판 간고등어에 비하여 radical 소거능, biogenic amine 및 기타 화학적 특질 면에서 우수하다고 판단되었다.