• 대한기계학회논문집B
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• 제20권3호
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• pp.1050-1060
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• 1996

Recently, attention has been paid to the flame diagnostic by noncontact methods which dose not deform the flame shape. One of them is a method which is using the radical luminous intensity. Generally, this diagnostic method using radical luminous has been investigated its reliability by applying to laminar flame. This study, however, investigated each radical luminous signals through stocastical analysis like auto-correlation, cross-correlation, phase and coherence which were acquired from measuring radical luminous intensity of OH, CH, $O_{2}$, radicals in turbulent diffusion flame. To compare radical luminous intensity in flame with temperature, ion current and concentration , radious distribution of each properties was investigated and considered. In radical luminous intensity, correlation in the reaction zone of flame was higher than in correlation in combusted gas zone. And radious distribution of radical luminous intensity was corresponded with radious distribution of temperature, ion current and concentration. The result of the study confirms that a radical luminous flame diagnosis is possible in the turbulent diffusion flame.

• BMB Reports
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• 제28권4호
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• pp.293-300
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• 1995

The radical centers detected in the reaction of metmyoglobin (MetMb) with hydrogen peroxide ($H_2O_2$) have been studied by using a spin trapping technique. A broad 5-line asymmetric electron spin resonance (ESR) spectrum, with $2A_{max}=4.07\;mT$ and $2A_{min}=2.97\;mT$, obtained after incubation of MetMb with $H_2O_2$ in the presence of a spin trap, 5,5-dimethyl pyrroline-N-oxide (DMPO) was gradually weakened with time and disappeared completely by 6 min after addition of guanidine-HCl (14 M). When a higher concentration (6 M) of the agent was added, the signal disappeared within 40 see and the DMPO/OH signal appeared immediately. Then, a new 8-line signal with similar intensities grew gradually and was fixed by 45 min, coexisting with the DMPO/OH signal. This new signal was found to be composite, consisting of two different radical species. One of the 6-line signals, with $a_N$ 1.49 mT and $a_H$ 0.988 mT, was assigned to the DMPO/phenoxyl radical adduct. The second 6-line signal with $a_N$ 1.55 mT and $a_H$ 2.22 mT was assigned to carbon-centered radical adduct. When 3,3,5,5-tetramethylpyrrolin-N-oxide (TMPO), was employed in the place of DMPO, another broad asymmetric 5-line signal was detected with $2A_{max}=3.99\;mT$ and $2A_{min}=3.04\;mT$, which is virtually identical to that obtained from the DMPO system The shape of the spectrum of the TMPO adduct changed drastically, with lapse of time resulting in a broad singlet after 40 min. The broad singlet was assigned to the porphyrin radical adduct. Incubation of globin with Fenton reagent in the presence of DMPO initially gave a DMPO/OH signal. Then, a new 12-line signal began to grow after one minute and fixed after 15 min. coexisting with the DMPO/OH signal, This 12-line signal was assigned to DMPO/phenoxyl with $a_N$ 1.47 mT, $a_{{\beta}H}$ 0.99 mT and $a_{{\gamma}H}$ 0.13 mT. A minor concentration of carbon-centered radical adduct was also detected. This radical composition is identical to that of guanidine HCl treated MetMb/DMPO/$H_2O_2$ system, indicating that the radical producing conditions are somehow common in both systems. Heme iron can be released by excess $H_2O_2$ in the MetMb/$H_2O_2$ system, providing for Fenton reagent. When MetMb was pretreated with tyrosine blocking agent, $KI_3$ the broad 5.line MetMb-derived signal was not detected in the MetMb/DMPO/$H_2O_2$ system, whereas no such effect was detected on such system of Hb in which the radical center was assigned to cysteine residue not tyrosine, indicating that tyrosine residue is a main radical center produced in the MetMb/$H_2O_2$ system Thus, the present data strongly support the previous indication that the apomyoglobin-derived radical center formed in the reaction of MetMb with $H_2O_2$ is a tyrosine residue.

• Journal of Applied Biological Chemistry
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• 제60권2호
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• pp.141-147
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• 2017

본 연구에서는 우산고로쇠(Acer okamotoaum) methanol (MeOH) 추출물과 n-BuOH, ethyl acetate (EtOAc), methylene chloride 및 n-hexane의 4종 분획물을 이용하여 free radical 소거능과 총 페놀, 플라보노이드 함량을 통한 항산화 효과를 측정하였으며, 신경교세포인 C6 glial cell을 이용하여 amyloid $beta_{25-35}$ ($A{\beta}_{25-35}$)에 의해 유도된 산화적 스트레스에서 신경세포 보호 효과에 대해 알아보았다. 그 결과 우산고로쇠 MeOH 추출물과 4가지 유기용매 추출 분획물은 우수한 1,1-diphenyl-2-picrylhydrazyl radical 소거능을 나타내었으며, 특히 EtOAc 분획물은 $4.47{\mu}g/mL$의 $EC_{50}$ 값을 나타내 가장 우수한 소거능을 가지고 있음을 확인할 수 있었다. Superoxide radical 소거능에서도 MeOH 추출물과 분획물은 높은 소거능을 보였으며, EtOAc 분획물은 $100{\mu}g/mL$ 농도에서 84.60%로 가장 높은 소거능을 나타내었다. 총 페놀과 플라보노이드 함량에서도 EtOAc 분획물은 다른 추출물과 분획물에 비해 월등히 높은 함량을 가지는 것으로 확인 되었다. 또한 $A{\beta}_{25-35}$에 의해 유발된 산화적 스트레스에서 우산고로쇠 MeOH 추출물과 4가지 유기용매 추출 분획물은 세포 생존율을 증가시켰으며, reactive oxygen species 생성을 감소 시키는 것으로 확인되었고 EtOAc 분획물이 가장 뛰어난 효과를 나타내었다. 본 연구 결과를 통해 우산고로쇠 MeOH 추출물과 4가지 유기용매 추출 분획물, 특히 EtOAc 분획물은 우수한 항산화 효과와 산화적 스트레스의 개선 효과를 가져 신경세포 보호에 효과가 있는 것으로 확인되었다.

• 대한환경공학회지
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• 제27권6호
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• pp.567-572
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• 2005

본 연구에서는 용존공기부상법(DAF)을 이용한 정수처리 공정에 오존을 도입하기 위하여 실험실 규모의 실험이 수행되었다. 오존의 수처리 적용시 공정제어 인자로 활용할 수 있는 I.D, $k_c$, 오존-Ct 및 OH 라디칼-Ct 등에 대한 반응속도론적 연구를 실시하였다. 또한 원수, DAF 처리수 및 여과수에 대한 오존처리 실험을 실시하여 오존공정의 최적 위치 및 주입량을 도출하였다. 실험 결과 오존-Ct와 OH 라디칼-Ct는 DAF 처리수에서 가장 높게 측정되었으며, DAF 공정의 체류시간인 30분 이후에도 계속적으로 유지되었다. 또한 각 공정수에 대한 오존처리 실험을 실시한 결과, 중오존이 전 후오존에 비해 높은 효율을 기대할 수 있을 것으로 나타났으며, 최적 오존주입농도는 $1{\sim}2\;mg/L$로 판단되었다. 이러한 결과로부터 중오존 / DAF(ozoflotation) 공정 도입을 위한 기초자료로서 활용하고자 하였다.

• 한국식품영양학회지
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• 제15권2호
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• pp.151-157
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• 2002

대두 배아로부터 saponin을 분리.정제하여 유리기 억제효과 및 동물의 암세포에 대한 세포 독성을 조사하였다. 유리기 억제활성에 대한결과를 보면 대두 배아 saponin을 0.5 및 1.0%씩 첨가한 급여 식에서 4주 동안 사육한 후 간장을 절취하여 간장 획분의 활성산소 및 항산화 관련 효소에 대하여 평가하였다. 간장의 mitochondria 및 microtome 획분의 hydroxy radical(.OH)의 생성에 미치는 영향에서 급여식에 사포닌을 첨가한 급여군에서 .OH기의 생성억제 효과를 나타내었다. 간장의 microsome 획 분에서도 0.5 및 1.0% 투여군에서 $H_2O$$_2$생성억제 효과가 인정되었다. 또한 간장의 cytosol획분에서 $O_2$.$^{-}$의 생성은 대조군에 비하여 현저한 억제 효과를 나타내었다. 대두 배아 사포닌의 세포독성을 P338 (mouse Iyoupoid neoplasm)과 L1210 (mouse leukemia) 세포주를 사용하여 실시한 결과 200 $\mu$g/mL 농도에서 높은 성장억제효과를 나타내었다. 그리고 처리 농도에 따른 대두배아 추출물이 P338과 L1210에 대한 성장 효과 실험에서도 200 $\mu$g/mL에서 은 성장억제 효과가 나타났으며 농도가 높을 수록 완전히 억제되는 것을 볼 수 있었다.

• Journal of Applied Biological Chemistry
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• 제65권4호
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• pp.321-327
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• 2022

본 연구는 생김치, 적숙기 및 과숙기 상태의 세 가지 발효단계별 김치의 이화학적 특성과 항산화 활성에 대해 알아보았다. pH 및 산도 측정을 통해 생김치(pH 5.6, 산도 0.3%), 적숙기 김치(pH 4.3, 산도 0.64%), 과숙기 김치(pH 3.7, 산도 1.24%)를 시료로 사용하였다. 발효가 진행될수록 glucosinolate의 함량이 증가하였으며, 특히 생김치, 적숙기 김치, 과숙기 김치의 glucoraphanin 함량이 가장 높았다. 뿐만 아니라, 발효가 진행되면서 항산화 물질로 알려진 glucoraphanin, sulforaphane, 및 총 폴리페놀 함량이 증가하였다. 발효단계별 김치 시료의 항산화 활성을 측정한 결과, 100, 250, 500 ㎍/mL의 농도에서 생김치에 비해 적숙기와 과숙기 김치의 DPPH radical 소거능이 우수하게 나타났으며, ·OH radical 소거능을 측정하였을 때 모든 농도(100, 250, 500, 1000 ㎍/mL)에서 적숙기와 과숙기 김치가 생김치에 비해 우수한 소거능을 나타낸 것으로 보아 김치의 발효가 진행될수록 radical 소거능이 증가함을 알 수 있었다. 이는 생김치에 비해 발효과정을 거친 적숙기 및 과숙기 김치가 glucosinolate, sulforaphane, 총 폴리페놀 함량이 증가하여 항산화 활성이 높게 나타난 것으로 사료된다.

• Archives of Pharmacal Research
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• 제27권4호
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• pp.390-395
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• 2004

The methanol extract obtained from the aerial parts of Aceriphyllum rossii (Saxifragaceae) was fractionated into ethyl acetate (EtOAc), n-BuOH and $H_2O$ layers through solvent fractionation. Repeated silica gel column chromatography of EtOAc and n-BuOH layers afforded six flavonol glycosides. They were identified as kaempferol 3-O-$\beta$-D-glucopyranoside (astragalin, 1), quercetin 3-O-$\beta$-D-glucopyranoside (isoquercitrin, 2), kaempferol 3-O-$\alpha$-L-rhamnopyranosyl $(1{\to}6)-\beta$-D-glucopyranoside (3), quercetin 3-O$\alpha$-L-rharnnopyranosyl $(1{\to}6)-\beta$-D-qlucopyrano-side (rutin, 4), kaempferol 3-O-[$\alpha$-L-rharnnopyranosyl $(1{\to}4)-\alpha$-L-rhamnopyranosyl $(1{\to}6)-\beta$-D-glucopyranoside] (5) and quercetin 3-O-[$\alpha$-L-rhamnopyranosyl $(1{\to}4)\alpha$-L-rhamnopyranosyl $(1{\to}6)\beta$-D-glucopyranoside] (6) on the basis of several spectral data. The antioxidant activity of the six compounds was investigated using two free radicals such as the ABTS free radical and superoxide anion radical. Compound 1 exhibited the highest antioxidant activity in the ABTS $\{2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)\}$ radical scavenging method. 100 mg/L of compound 1 was equivalent to $72.1\pm1.4\;mg/L$ of vitamin C, and those of compounds 3 and 5 were equivalent to $62.7\pm0.5\;mg/L$ and $54.3\pm1.3\;mg/L$ of vitamin C, respectively. And in the superoxide anion radical scavenging method, compound 5 exhibited the highest activity with an $IC_{50}$ value of $17.6{\pm}0.3{\mu}M$. In addition, some physical and spectral data of the flavonoids were confirmed.

• Korean Chemical Engineering Research
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• 제58권1호
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• pp.59-63
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• 2020

PEMFC 고분자막의 내구성을 향상시키기 위해서 Radical 제거제가 사용되고 있다. 본 연구에서는 라디칼 제거제로서 해조류에서 추출한 후코이단이 고분자막의 전기화학적 열화를 방지하는지 Fenton 실험과 가속내구 평가방법(OCV Holding) 실험을 통해 검토하였다. 후코이단은 항산화 효과가 있어 과산화수소와 산소 라디칼로부터 고분자막을 보호해 열화속도를 1/10로 감소시켰다. 후코이단이 라디칼 제거제로 사용되는 MnO₂보다 효과적임을 보였다. PEMFC셀에서 OCV Holding 실험한 결과, 후코이단이 고분자막의 수소투과도를 12% 감소시켰고, 성능은 라디칼 제거제가 없을 때 보다 29.1% 감소시켜 PEMFC 셀에서도 라디칼 제거제의 역할을 함을 확인하였다. 그리고 후코이단을 Anode쪽보다 Cathode 쪽 전극 이오노머에 넣은 것이 더 효과적임을 확인하였다.

• Preventive Nutrition and Food Science
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• 제13권2호
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• pp.77-83
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• 2008

To further the goal of isolating Bacillus sp. from commercial chungkukjang (CKJ) for a development of a probiotic dietary adjunct using soymilk or milk, antioxidant activity of CKJ purchased from the Sunchang Traditional Village in Chunbook province was examined. Six CKJ samples were evaluated and 3 were selected based on the results of the physicochemical analysis and sensory evaluation for further antioxidant study. $IC_{50}$ for DPPH scavenging activity of methanol extracts of CKJ ranged from 238.1 to 345.7 ${\mu}g/mL$. CKJ exhibited over 80% scavenging of ${\cdot}OH$ and ONOO- at concentrations of 100 ${\mu}g/mL$ and 250 ${\mu}g/mL$, respectively. $O_2^-$ and NO scavenging activities of three CKJ were increased in a dose dependent manner with the concentration tested from 100 to 1000 ${\mu}g/mL$. In this study, the methanol extract of CKJ exhibited a great reduction capability and powerful free radical scavenging activity, especially against OH. and ONOO-, which are the most toxic radicals responsible for oxidative damage in the body. However, radical scavenging effects of CKJ on DPPH, $O_2^-$, and nitrite radical were rather moderate. In conclusion, CKJ may reduce the oxidative stress in the body by scavenging the free radicals.

• 한국연소학회지
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• 제8권3호
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• pp.38-48
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• 2003

OH, CH and NO radical distributions have been measured and compared with the numerical analysis results in methane/air partially premixed laminar flames using 2-D LIF technique. The pick intensity of OH LIF signal is insensitive to fuel equivalence ratio: however, CH LIF intensity decreases as equivalence ratio increases and the NO concentration increases with equivalence ratio. The contribution of the prompt NO, formed near premixed reaction zone, to the total NO formation is evident from the OH, CH, and NO PLIF images in which the dilution effect of nitrogen is minimal for the highest equivalence ratio. Measured OH and NO LIF signals in counterflow flames agree with the computed concentration distributions. Both numerical and experimental results indicate that the structural change in a flame alters the NO formation characteristics of a partially premixed counterflow flame. The nitrogen dilution also changes flame structure, temperature and OH radical distributions and results in the decreased NO concentrations in a flame. The levels of decrease in NO concentrations, however, depends on the premixedness(${\alpha}$) of a flame. The larger change in the flame structure and NO concentrations have been observed in a premixed flame(${\alpha}=1.0$), which implies that the premixedness is likely to be a factor in the dilution effect on NO formation of a flame.