• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 가을 학술발표회 논문집
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• pp.177-178
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• 2003

Many researchers have made efforts to control the stereoregularity in radical polymerization of vinyl monomers because the physical and chemical properties of the polymer are significantly affected by the stereostructure.[1]-[4] In general, monomer design, reaction conditions(e.g. solvent, temperature, and monomer concentration), and additives can alter the stereochemistry of the radical polymerization of acrylic monomer. (omitted)

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.633-635
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• 2007

To cope with increasing power demand in metropolitan area, the power system in Korea has equipped with unit generator of large capacity, high density and uneven distribution, and transmission line of long distance, large capacity and high voltage. As the power system growing up enormous, it has become difficult to maintain the standard voltage in case of radical fluctuation of load or severe change of voltage by power system fault for its weakness of responsive characteristics although the power condenser has been installed to solve the unstability by lack of reactive power. Consequently, we review harmonic wave production and control characteristics to solve unstability problem of voltage in northern metropolitan, to reduce transmission restriction cost and to minimize load shedding by relocation of SVC (Static Var Compensator), which is highly effective for improvement of responsive characteristics for radical voltage fluctuation.

• 한국식품영양과학회지
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• 제23권3호
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• pp.402-408
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• 1994

인체의 혈장 저밀도 지단백(LDL)은 관상동맥경화 발병의 주 요인이다. 그러나 최근의 연구들은, 정상적인 LDL은 산소 자류라디칼에 의해 쉽게 산화되며, 결과 LDL 수용채와 결합하지 못한다고 밝히고 있다. 따라서 이 변형된 형태의 산화된 LDL은 macrophage scavernger receptor에 의해 인식되어 foam cell을 형성하여, 동맥혈관이 좁아지는 역할을 수행한다고 알려지고 있다. 지리과 산화에는 지방산이 중요한 작용을 하므로, 한국인의 LDL의 지방산 조성을 분석하여 서양인과 비교하였다. 결과, 한국인의 불포화 지방산의 비율이 총 지방산 함량의 약 30%인 반면 서양인은 약 70%의 분포를 갖고 있는 것으로 발표되었다. 따라서 한국인이 서양인에 비해 LDL의 산화에 대한 영향을 적게 받을 수 있으며, 따라서 동맥경화나 심장병의 발생률이 훨씬 적을 것으로 결론을 내릴 있다. 정상적인 LDL을 황산구리와 함께 배양하여, 지방의 산화를 유도하였으며 이의 정도를 지방산 산화의 생성물인 TBARS를 측정하여, LDL이 산화될 때 생성되는 자유라디칼의 양을 측정하므로서 비교하였다. 이 때, 항상화제인 비타민 C; 비타민 E와 히알우로닉산을 첨가하면 LDL의 산화가 억제되는 효과를 확인하였다. 자유 라디탈이 증가함에 따라 산화의 정도도 증가하였으며, 자유라디칼 형성의 경시적 변화는 TBARS와 유사하였다. 따라서 luminometer에 의한 자유라디칼의 정량은 TBARS에 의한 것보다 훨씬 간편한 것으로 나타났다.

• 한국생활과학회지
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• 제23권5호
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• pp.929-940
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• 2014

본 연구에서는 AVP를 첨가(0, 2, 4, 6, 8%)한 쿠키를 제조하여 쿠키의 품질특성과 항산화 활성을 측정하였다. 실험결과 반죽 pH는 AVP 첨가량이 증가할수록 유의적으로 감소하였고, 반죽 밀도는 대조군과 2%와 4% AVP는 유의적 차이가 없었으나 6%와 8% AVP군에서는 유의적으로 증가하여(p<0.001) 대체로 AVP 첨가량이 증가함에 따라 증가하는 경향이었다. 퍼짐성 지수는 대조군과 2% AVP 간에는 유의적 차이가 없었으나, 4% AVP이상에서는 대조군보다 유의적으로 증가하여 (p<0.001), AVP 첨가량이 증가함에 따라 증가하였고, 수분함량도 AVP 첨가량이 증가함에 따라 증가하는 경향이었다(p<0.001). 쿠키의 색도는 대조군에 비해 AVP 첨가량이 증가함에 따라 L값은 감소, a값과 b값은 증가하는 경향이었다. 경도는 AVP 첨가량에 따라 감소하였다(p<0.001). AVP 첨가 쿠키의 총 페놀 화합물과 DPPH radical 소거능을 측정한 결과 첨가량이 증가함에 따라 총 페놀 화합물과 DPPH radical 소거능이 증가하였다. 쿠키의 관능검사(색, 맛, 외관, 조직감, 향, 전반적인 기호도)에서, 외관을 제외하고는 색, 맛, 조직감, 향, 전체적 기호도는 4% AVP가 대조군보다 높았다. 대체적으로 대조군, 2%와 6% AVP는 유의적 차이가 없었으나 8% AVP는 유의적으로 낮았다(p<0.001). 이상의 결과로 알로에 첨가 쿠키 제조 시 품질특성, 항산화성, 기호도 면에서 4%의 AVP을 첨가하는 것이 가장 적합할 것으로 본다.

• 한국생활과학회지
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• 제23권3호
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• pp.443-452
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• 2014

본 연구에서는 백복령 가루를 첨가(0, 3, 6, 9, 12%)한 쿠키를 제조하여 쿠키의 품질특성과 항산화 활성을 측정하였다. 실험결과 반죽 pH는 백복령 가루 첨가량이 증가할수록 유의적으로 감소하였고, 반죽 밀도는 대조군에 비해 백복령 가루 첨가량에 따라 유의적으로 낮아지다가(p<0.001), 9%와 12% 첨가군 사이에는 유의적인 차이가 없었다. 퍼짐성 지수는 백복령 가루 첨가량이 증가함에 따라 유의적으로 감소하였고, 반대로 수분함량은 유의적으로 증가하였다. 쿠키의 색도를 보면 대조군에 비해 백복령 첨가량에 따라 L값과 b값은 감소, a값은 증가하는 경향이었고, 경도는 유의적으로 증가하였다. 백복령 가루첨가 쿠키의 총 페놀 화합물과 DPPH radical 소거능을 측정한 결과 첨가량이 증가함에 따라 총 페놀 화합물과 DPPH radical 소거능이 증가하였다. 쿠키의 관능검사(색, 맛, 외관, 조직감, 향, 전반적인 기호도)에서, 쿠키의 색과 맛, 전체적 기호도에 대한 관능검사 점수는 대조군, 3%와 6% 첨가군은 유의적인 차이가 없었으나 9%와 12% 첨가군은 유의적으로 낮아졌다. 조직감은 3%와 6% 첨가군이 대조군과 다른 군보다 유의적으로 높았으며(p<0.001), 외관, 향은 백복령 가루 첨가량에 따라 낮아지는 경향이었다. 이로보다 백복령 첨가 쿠키 제조 시 품질특성, 항산화성, 기호도 면에서 3%~6% 백복령 가루를 첨가하는 것이 가장 적합한 레시피가 되겠다.

• Archives of Pharmacal Research
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• 제28권1호
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• pp.22-27
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• 2005

Bioassay-guided fractionation of methanol extract of Reynoutria sachalinensis flower using DPPH assay has led to the isolation of three anthraquinones and three flavonoids. Their structures were identified as emodin (1), emodin-8-O-$\beta$-D-glucopyranoside (2), physcion-8-O-$\beta$-D­glucopyranoside (3), quercetin-3-O-$\alpha$-L-arabinofuranoside (4), quercetin-3-O-$\beta$-D-galactopyra­noside (5), and quercetin-3-O-$\beta$-D-glucuronopyranoside (6) by comparing their physicochemical and spectral data with those published in literatures. All isolated compounds were evaluated for antioxidant activities with free radical 1, 1-diphenyl-2-picrylhydrazyl (DPPH) scavenging, superoxide radical scavenging and $Cu^{2+}$-mediated low density lipoprotein (LDL) oxidation assay. The results demonstrated that three flavonoids, 4, 5, and 6 had remarkable antioxidant activities with the $IC_{50}$ values of 64.3, 54.7, and 46.2${\mu}M$ (DPPH scavenging), the $IC_{50}$ values of 6.0, 6.7, and $4.4{\mu}M$ (superoxide radical scavenging) and the $IC_{50}$ values of 3.8, 3.2, and 5.4${\mu}M$ against LDL oxidation, respectively.

• Preventive Nutrition and Food Science
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• 제22권1호
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• pp.16-20
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• 2017

This study investigated the antioxidant activity of functional beverage concentrates containing herbal medicine extracts (FBCH) using various antioxidant assays, such as 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging activity, and reducing power assay. The total polyphenolic content of FBCH (81.45 mg/100 g) was higher than Ssanghwa tea (SHT, 37.56 mg/100 g). The antioxidant activities of FBCH showed 52.92% DPPH and 55.18% ABTS radical scavenging activities at 100 mg/mL, respectively. FBCH showed significantly higher antioxidant activities compared to the SHT (DPPH, 23.43%; ABTS, 22.21%; reducing power optical density; 0.23, P<0.05). In addition, intracellular reactive oxygen species generation significantly decreased in a concentration-dependent manner following FBCH treatment. These results suggest that the addition of herbal medicine extract contributes to the improved functionality of beverage concentrates.

• 한국식품조리과학회지
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• 제27권3호
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• pp.39-49
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• 2011

This study was conducted to evaluate the effects of adding unrefined oil on the antioxidant activity of a tuna oil-enriched emulsion by determining DPPH radical scavenging activity, reducing power, and inhibition of low-density lipoprotein (LDL) oxidation in vitro. The emulsion consisted of tocopherol-stripped canola (18.3 g) and tuna (9.1 g) oil, one of the unrefined oils (4.6 g), such as extra virgin olive, mustard, perilla, or sesame oil, 0.5% acetic acid (64 g), and egg yolk powder (4 g). The control emulsion contained only canola (21.4 g) and tuna oil (10.6 g), as oil sources,with the same composition of the remaining ingredients. The emulsion with added unrefined oil, particularly mustard oil, showed higher radical scavenging activity and reducing power than those of the control emulsion. The radical scavenging activity and reducing power of the emulsion with added unrefined oil were higher at 1,000 ppm than at 500 ppm thus, the effect was concentration-dependent. Adding sesame or perilla oil to the tuna oil-enriched emulsion resulted in higher inhibition of LDL oxidationwhereas adding olive oil increased LDL oxidation. The results clearly showed that adding roasted mustard, sesame, or perilla oil improved the antioxidant activity of a tuna oil-enriched emulsion by increasing free radical scavenging activity, reducing power, and inhibiting LDL oxidation. The results also suggest that adding unrefined oils produces a healthier fish oil-enriched salad dressing recipe.

• Preventive Nutrition and Food Science
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• 제9권2호
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• pp.167-173
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• 2004

The aim of this study was to investigate the antioxidant effect of medicinal plants used by diabetic patients. Fourteen medicinal plants were selected and antioxidant activity such as 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, inhibition effect of linoleic acid autoxidation and low density lipoprotein (LDL) oxidation, thiobarbituric acid (TBA) value were measured. The Cornus officinalis had DPPH radical scavenging activity of 84.79%, which was higher than the 78.79% for $\alpha$-tocopherol. Rosa rugosa Thunberg, Pueraria thundergiana Bentham, Artemisia princeps var. orientalis and Sasamorpha purpurascens Nakai also had high values. Extracts with higher DPPH radical scavenging activities had higher total phenol concentrations, and positive correlations between these parameters were found. Inhibitory activities of linoleic acid autoxidation, LDL oxidation and TBA value, used as indices of oxidative stress, were observed in most of the selected medicinal plants. The highest inhibitory activity for TBA value was observed in the extract of Pueraria thundergiana Bentham. Rosa rugosa Thunberg (75.50 %), Sasamorpha purpurascens Nakai (74.00 %), and Cornus officinalis (73.00 %) all had high antioxidant activity against linoleic acid autoxidation, similar to that of $\alpha$-tocopherol. The same 3 plants also had high in inhibitory activity against LDL oxidation. Therefore, we demonstrated that medicinal plants used as folk remedy by diabetic patients had antioxidant activity. Especially, Rosa rugosa Thunberg, Cornus officinalis, Pueraria thundergiana Bentham, Arlemisia princeps var. orientalis, and Sasamorpha purpurascens Nakai had high phenol concentrations which resulted in high values for DPPH radical scavenging. These same plants exhibited high values for inhibitory activities for TBA value, linoleic acid autoxidation and LDL oxidation, indices associated with lipid peroxidation.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.74-74
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• 2010

The aqua-plasma is the non-thermal plasma in electrical conductive electrolyte by generates the vapor film layer on the immersed metal electrode surface. This plasma can generate the hydroxyl radical by dissociate the water molecule with the plasma electron. To develop the plasma discharge device for high efficiency in the hydroxyl radical generation, proper model for estimation of plasma power is necessary. In this work, the 1-D spherical model was developed, considering temperature dependence material constants. The relation between the plasma power and hydroxyl generation was also studied by the comparison between the optical emission intensity from the hydroxyl radical using monochromator and estimated plasma power. First, the thickness of vapor layer thickness was estimated using the Navier-Stokes fluid equation in order to calculate the discharge E-field inside vapor layer. Using the E-field magnitude and power balance on the plasma generation, it was possible to estimate the plasma power. The plasma power was assumed to uniformly fill the vapor layer and the temperature of vapor layer was fixed in the boiling temperature of electrolyte, 375K. In the experiment, the aqua-plasma was discharged in the saline by applied the voltage on the bipolar electrode. The range of applied voltage was 234 to 280V-rms in the frequency of 380 kHz. Two type electrodes were produced with two ${\Phi}0.2$ tungsten. The plasma power was estimated from the V-I signal from the two high voltage probes and current probe. The estimated plasma power agreed with the profile of emission intensity when the plasma discharged between the metal electrode and vapor layer surface. However, when the plasma discharged between the metal electrodes, the increasing rate of emission intensity was lower than the increase of plasma power. It implies that the surface reaction is more sufficient rather than the volume reaction in the radical generation, due to the high density of water molecule in the liquid.