• 한국육종학회지
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• 제42권2호
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• pp.129-138
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• 2010

Total phenolic content, total anthocyanin content and antioxidant activity were analyzed from rice samples collected in Korea, Japan and China. The results showed that the total phenolic content and free-radical scavenging activity differed significantly in these rice lines. The correlation between content and activity was subsequently investigated. The results showed that in black rice, anthocyanin was the major phenolic component and that both phenolic content and anthocyanin content were closely correlated with free-radical scavenging activity. Reverse Phase High Performance Liquid Chromatography (RP-HPLC) data showed that cyanidin-3-O-glucoside and peonidin-3-O-glucoside composed about 90% of the total anthocyanin content in black rice and in red rice. In the red rice extract, the total phenolic content produced a high correlation coefficient with antioxidant activity but correlated very poorly with the total anthocyanin content. The $OD_{458}$ and the $OD_{500}$ values which represent the proanthocyanidin content of the rice extract, produced high correlation coefficients with antioxidant activity and total phenolic content. These results suggest that the $OD_{458}$ and the $OD_{500}$ values can be used to evaluate the quality of red rice. In addition, based on the data obtained, a competitive accumulation model of anthocyanin and proanthocyanidin in black and red rice was proposed.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.22-24
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• 2008

This paper presents a numerical model of internal flows in a lubricant supplying and scavenging flow path of an aero-engine lubrication system. The numerical model was built in the General Analysis Software of Aero-engine Lubrication System, GASLS, developed by Northwestern Polytechnical University. The lubricant flow flux, pressure and temperature distribution at steady state were calculated. GASLS is a general purpose computer program employed a 1-D steady state network algorithm for analyzing flowrates, pressures and temperatures in a complex flow network. All kinds of aero-engine lubrication systems can be divided into finite correlative typical elements and nodes from which the calculation network be developed in GASLS. Special emphasis is on how to use combined elements which is a type of typical elements to replace some complex components like bearing bores, accessory gearboxes or heat exchangers. This method can reduce network complexity and improve calculation efficiency. Final computational results show good agreement with experimental data.

• 한국지구과학회지
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• 제42권4호
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• pp.390-400
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• 2021

Ocean biogeochemistry plays a crucial role in sustaining the marine ecosystem and global carbon cycle. To investigate the oceanic biogeochemical responses to iron parameters in the tropical Pacific, we conducted sensitivity experiments using the Nucleus for European Modelling of the Ocean-Tracers of Ocean Phytoplankton with Allometric Zooplankton (NEMO-TOPAZ) model. Compared to observations, the NEMO-TOPAZ model overestimated the concentrations of chlorophyll and dissolved iron (DFe). The sensitivity tests showed that with increasing (+50%) iron scavenging rates, chlorophyll concentrations in the tropical Pacific were reduced by approximately 16%. The bias in DFe also decreased by approximately 7%; however, the sea surface temperature was not affected. As such, these results can facilitate the development of the model tuning strategy to improve ocean biogeochemical performance using the NEMO-TOPAZ model.

• 농업과학연구
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• 제43권2호
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• pp.186-193
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• 2016

This study focused on the evaluation of the antioxidative effects of lotus seeds from golden colored flowers. The lotus seeds were extracted with ethanol and then fractionated into 4 fractions, ethyl acetate (EtOAc), n-butanol, methylene chloride, and n-hexane. The comparison of antioxidative activities of the extract and fractions from the lotus seeds was carried out using an in vitro radical scavenging model and the total phenol content was analyzed. Of the tested extracts and fractions, the EtOAc fraction of the lotus seeds showed the strongest 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity with 96.24% at a concentration of $100{\mu}g/mL$. In addition, the hydroxyl radical scavenging activity of the lotus seed EtOAc fraction was also increased in a concentration dependent manner with the concentrations tested ranging from 5 to $100{\mu}g/mL$. Moreover, the EtOAc fraction showed the highest scavenging activity for nitric oxide and superoxide anion radicals. In particular, of all the extracts and fractions, the EtOAc fraction showed highest contents of total phenols. These results indicate that lotus seeds have potential as an antioxidative agent against oxidative stress involving reactive oxygen species. Furthermore, the EtOAc fraction of lotus seeds includes promising oxidative stress-protective compounds.

• 생약학회지
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• 제45권2호
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• pp.147-153
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• 2014

This study was focused on the evaluation of radical scavenging effect and the protective activity against oxidative stress of the extract and fractions from Petasites japonicus. P. japonicus was extracted with methanol and then fractionated into 4 fractions [n-butanol, ethyl acetate (EtOAc), methylene chloride, and n-hexane]. The extract and fractions showed strong 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity. Among all the fractions, particularly, the EtOAc fraction showed the strongest effect with the $IC_{50}$ value of $0.02{\mu}g/ml$. In addition, the fractions also showed strong hydroxyl radical scavenging activity and nitric oxide scavenging activity as well. Furthermore, cell viability generated by the P. japonicus extract and 4 fractions were examined under C6 glial cellular model. The C6 glial cells showed high generation of reactive oxygen species (ROS) and decrease in cell viability by the treatment generator of hydrogen peroxide. However, the production of ROS formation was decreased by the treatment of the fractions of P. japonicus and also founded that the EtOAc fraction led to significant increase in the cell viability at concentration $100{\mu}g/ml$. Results from this work indicated that P. japonicus showed protective effects against oxidative stress and its EtOAc fraction may be served as a useful natural antioxidant.

• 대한환경공학회지
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• 제36권8호
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• pp.534-541
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• 2014

본 논문은 먹는물 처리공정에 적합한 고도산화공정 중 하나인 자외선/과산화수소공정의 효율적인 운전을 위한 최적 운전 조건을 도출하는 방법을 연구하였다. 자외선/과산화수소 공정에서 대상물질의 제거효율을 예측하고 그에 따른 운전조건을 도출하기 위한 핵심 인자인 수산화라디칼 소모인자를 보다 쉽고 빠르게 측정하기 위해 새로운 지표물질인 로다민 비(Rhodamin B, RhB)를 선정하여 검증하였다. 그 결과, 기존 지표물질인 para-Chlorobenzoic acid (pCBA)와 비교해 약 1.1% 이하의 오차율로 높은 신뢰성을 가진 것을 확인하였다. 검증된 RhB를 이용하여 측정한 수산화라디칼 소모인자 및 모델링을 통해 대상물질(Ibuprofen)의 제거효율 예측 가능성을 평가한 결과, 실제 실험값과 평균 오차율 약 5% 내외로 거의 일치하였다. 약 8개월간의 자외선/과산화수소공정 파일럿 플랜트 유입수의 수산화라디칼 소모인자 모니터링 결과, 최대 두 배 정도의 차이로 크게 변화하였다. 이 차이는 미량오염물질 중 하나인 Caffeine의 목표 제거율을 만족하기 위한 자외선 에너지를 약 1.7배 증가시켜야 할 정도로 큰 값이다. 이상의 결과를 통해 자외선/과산화수소 공정을 안전하고 효율적으로 운전하기 위해서는 수산화라디칼 소모인자의 측정이 매우 중요하며, 측정된 소모인자, 자외선 흡광도($A_{254}$), 대상물질의 정보만 입력하면 자외선/과산화수소 공정을 쉽게 제어할 수 있음을 확인하였다.

• Food Science and Biotechnology
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• 제16권5호
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• pp.753-758
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• 2007

This study was conducted to investigate the antioxidant activity of paprika in the lard-pork model system adding ground fresh paprika (3%) and paprika powders (5%). Paprika powders were obtained through 4 drying methods (freeze, vacuum, far infrared-ray, and hot-air). In the lard and meat-fat mixture (containing lard 30%) containing paprika powders, the rate of increase in the peroxide value (POV) and thiobarbituric acid (TBA) value decreased notably during the refrigerated storage ($4^{\circ}C$) compared to the control without paprika. Therefore, paprika powders showed potent antioxidant activity and especially the freeze dried paprika powder revealed the most effective activity among them. However, its antioxidant activity was still lower than that of the fresh paprika because the addition of fresh paprika in the lard and meat-fat mixture merely increased the POV and TBA value. In linoleic acid oxidation, the addition of capsanthin 500 ppm to mixed linoleic acid and 10 ppm of $FeCl_3$ (LF) inhibited the formation of peroxides by 15.2% compared to LF, showing its iron scavenging ability. When mixed antioxidants (${\beta}$-carotene 200 ppm + ascorbic acid 100 ppm, capsanthin 200 ppm + ascorbic acid 100 ppm) were added in LF, synergistic effects were obtained with 57.7 and 60.4% of inhibition of peroxide formation, respectively.

• 대한수의학회지
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• 제47권1호
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• pp.25-32
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• 2007

Houttuynia cordata root on non-lipid oxidative damage. The antioxidative efects of methanolic (MeOH) extract of Houttuynia cordata rooton non-lipid, including liposome oxidation, oxidation of deoxyribose, protein oxidation, chelating, scavenging,and 2'-deoxyguanosine (2'dG) oxidation were investigated. Houttuynia cordata root exhibited highantioxidative effect in a liposome model system. The inhibitory effect of MeOH extract on deoxyribosedamage exhibited antioxidative effect and it afforded considerable protection against damage to deoxyribose.In addition, MeOH extract at over 300extracts exhibited metal binding ability for hydrogen peroxide. Furthermore, the oxidation of 2'dG to 8-hydroxy-2-deoxyguanosine was inhibited by MeOH extracts, and scavenging activity for hydroxyl radicalexhibited a remarkable effect. The present results on biological model systems showed that MeOH extractswas effective in the protection of non-lipids against various oxidative model systems.

• 한국식생활문화학회지
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• 제29권6호
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• pp.623-636
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• 2014

This study was performed to determine the optimal composition of muffins added with dropwort powder, egg and sugar. The experiment was designed based on BBD (Box-behnken design), and evaluation was carried out by means of RSM (response surface methodology), consisting of 13 experimental points with three replicates each for three independent variables dropwort powder, eggs and sugar. Using F-test, height, moisture, 1,1-diphenyl-2picriylhydrazyl (DPPH) radical scavenging activity, L-value, a-value, springiness, cohesiveness, chewiness, brittleness, color, and appearance acceptability were expressed as a linear model, whereas pH, b-value, flavor, taste, and texture were expressed as a quadratic model. After swallow and overall acceptability were expressed as a 2FI model. As dropwort powder content increased, 1,1-diphenyl-2picriylhydrazyl (DPPH) radical scavenging activity increased. Increasing amounts of dropwort powder led to reduction of sensory scores for color, appearance, flavor, taste, and texture quality. The optimum formulation determined by the numerical and graphical methods were similar: dropwort powder 6 g, egg 77 g, and sugar 60 g.

• 한국대기환경학회지
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• 제19권2호
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• pp.191-204
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• 2003

A one dimensional time dependent acid rain model considering size distribution of aerosols and hydrometeors is developed to predict observed chemical and physical properties of precipitation. Temporal variations of anions and cations observed are predicted fairly well with acid rain model simulations. It is found that aerosol depletion rates are highly dependent on aerosol sizes under the assumption of Marshall - Palmer raindrop size distribution. Also, the aerosol depletion during the initial rain event largely influences on ion concentrations in rainwaters.