• Journal of Photoscience
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• 제6권3호
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• pp.91-96
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• 1999

Zeolites and microporouos materials continue to attract attention as novel hosts for photochemical reactions. Zeolities are attractive because of their ability to selectivity exchange and incorporate species within the void spaces and interconnecting channels, providing a spatial arrangement of molecules. Our research has primarily focused on intrazeolitic electron transfer from excited Ru(bpy)32+ in supercages of zeolite Y to a series of bipyridinium ions. In the Ru(bpy)32+ viologen-zeolite Y samples, the slowing of the back electron transfer from the bipyridinium radical cation to Ru(bpy)32+ allows for charge propagation via self exchange between diquat molecules. This provides an opportunity for permanent charge separation. When the migrating charge on the diquat radical within the zeolite reaches the surface, it can be transferred to a neutral viologen (PVS) in solution, resulting in permanent charge separation. The advantage of long-lived charge separation can be exploited for useful chemistry if suitable catablysts can be assembled on the zeolities. We have studied Ru(bpy)2 as water oxdiation catalysts. We have demonstrated that synthesis of RuO2 fibers on a zeolite via thermal decomposition of Ru3(CO)12 leads to the most active water decomposition catalyst reported to date. Because of the extensive interest of photochemical water reduction to H2, much is known about catalytic systems usin gone electron catalyst, and even more importantly, that no reaction of viologen occurred with H2 over this catalyst. The present challenge is to incorporate all these elements of the system into an architecture and we are examining zeolite membranes for this purpose.

• Food Science and Biotechnology
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• 제17권6호
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• pp.1387-1390
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• 2008

This study evaluated the effects of heat treatment on antioxidant activity of Rehmannia radix Libosch (RRL). RRL was heated at various temperatures ($110-150^{\circ}C$) for various times (1-5 hr), and the total polyphenol, flavonoid content, and antioxidant activity were investigated. With increased heating temperature and exposure time, total content of polyphenol, flavonoid, as well as antioxidant activity increased. The highest total polyphenol and flavonoid contents were 21.65 and 3.56 mg/g, respectively, these values were occurred after heating for 3 hr at $150^{\circ}C$ (RRL was 5.09 and 0.83 mg/g, respectively). The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity was highest value of 83.46% after heating for 3hr at $150^{\circ}C$. The 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) cation radical scavenging activity was highest value of 20.43mg ascorbic acid (AA) eq/g after heating for 2 hr at $150^{\circ}C$. There were highly significant differences in the total polyphenol, flavonoid content, and antioxidant activity among heating temperatures and times (p<0.001), with heating temperature having the greater effect.

• 한국식품조리과학회지
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• 제32권5호
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• pp.600-608
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• 2016

Purpose: To investigate the antioxidant, physicochemical sensory, and microbial safety qualities of sunsik containing fermented Curcuma longa L. powder. Methods: Quality characteristics of samples were measured using pH, moisture content, crude ash content, color and sensory evaluation. Antioxidant activities of samples were compared using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)(ABTS) cation radical scavenging activities. Microbial safety of samples were tested for Aerobic plate counts, Salmonella spp., Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus, and Escherichia coli O157:H7. Results: The pH of samples was between pH 5.51 and pH 5.64, which was significantly lower than the optimum microbial living range. The DPPH and ABTS radical activities of sunsik containing 0.8% fermented Curcuma longa L. were significantly increased compared to that of the control (p<0.05). In sensory intensities, sunsik containing 0.8% fermented Curcuma longa L. showed significantly (p<0.05) similar savoy aroma and flavor, spicy aroma, spicy hot flavor, sweet flavor, and throat swallowing values to those of the control samples. Samples of sunsik added 0.8% and 1.2% fermented Curcuma longa L. showed significantly similar overall acceptance values to those of the control. All samples tested were found to free of microbes and microbiologically safe according to the food code standards. Conclusion: The sunsik added with 0.8% or 1.2% fermented Curcuma longa L. powder were successfully developed. we conclude that the developed sunsik with the fermented turmeric powder can be potentially high value products in the highly competitive sunsik food industry.

• Bulletin of the Korean Chemical Society
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• 제35권3호
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• pp.833-838
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• 2014

The energy- and time-dependent branching to the competing dissociation paths are studied by theory for coupled unimolecular dissociations of the o-, m-, and p-chlorotoluene radical cations to $C_7{H_7}^+$ (benzylium and tropylium). There are four different paths to $C_7{H_7}^+$, three to the benzylium ion and one to the tropylium ion, and all of them are coupled together. The branching to the multiple paths leads to the multiexponential decay of reactant with the branching ratio depending on both internal energy and time. To gain insights into the multipath branching, we study the detailed kinetics as a function of time and internal energy on the basis of ab inito/RRKM calculations. The number of reaction steps to $C_7{H_7}^+$ is counted for each path. Of the three isomers, the meta mostly goes through the coupling, whereas the para proceeds with little or no coupling. In the beginning, some reactants with high internal energy decay fast to the benzylium ion without any coupling and others rearrange to the other isomers. Later on all three isomers dissociate to the products via long-lived intermediates. Thus, the reactant shows a multiexponential decay and the branching ratio varies with time as the average internal energy decreases with time. The reciprocal of the effective lifetime is taken as the rate constant. The resulting rate-energy curves are in line with experiments. The present results suggest that the coupling between the stable isomers is thermodynamically controlled, whereas the branching to the product is kinetically controlled.

• 생명과학회지
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• 제23권6호
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• pp.751-756
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• 2013

본 연구는 노령목의 산림의 경제적 가치를 증진하고자 밤나무 잎에 함유된 물질의 기능성화장품 원료로의 기능을 규명하여 화장품 산업에 적용하기 위하여 천연소재로써의 이용 가능성을 살펴보았다. 항산화능 측정을 위한 실험으로 DPPH radical 소거능과 ABTS cation radical 소거능을 실시하였으며, 양성 대조군으로는 항산화 작용이 있는 것으로 알려진 BHA를 이용하여 밤잎 추출물의 항산화 효과를 비교하였다. 그 결과 아세톤 추출물의 경우 시료 농도에 따라 DPPH radical 및 ABTS radical 소거 증가 정도가 컸으며, 열수 추출물은 10 ug/ml의 농도에서 50% 이상의 소거활성을 나타내었다. 이러한 결과로 미루어 볼 때 밤잎 추출물은 항산화 작용이 높고 피부에서 흔히 일어나는 활성산소에 대한 노화 방지에 도움이 될 것으로 사료된다. 주름개선 효과 측정으로 elastase 저해활성을 측정한 결과 아세톤과 열수 추출물에서는 그 효과가 없었으나 에탄올 추출물 100 ug/ml에서 64.6%의 우수한 elastase 저해활성을 나타내었으며, collagenase 저해활성을 측정한 결과 3가지 추출물은 100 ug/ml에서 열수 추출물 18.0%, 아세톤 추출물 14.3%, 에탄올 추출물 5.3%의 순으로 collagenase 저해활성능을 나타내었으며, 다른 천연물질을 이용한 연구결과와 비교 시 밤잎 추출물은 주름개선에 우수함을 확인 할 수 있었다. 주름개선 원료로의 이용가치가 있을 것으로 보인다. 이상의 연구 결과로 보아 밤잎은 항산화 및 항노화 효소 활성을 갖는 천연소재로서 주름개선 소재로 활용 될 수 있을 것으로 사료되며, 임삼 효능 평가 등의 계속적인 연구를 통해 기능성 화장품 소재로 개발된 가능성이 매우 높다고 사료된다.

• 생명과학회지
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• 제20권8호
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• pp.1235-1240
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• 2010

천연물들은 현재까지 합성 항산화제들을 대체하기 위하여 많은 연구가 이뤄지고 있다. 본 연구에서는 천연 항산화제로서 화장품과 바이오산업에 적용하기 위해 정금나무 열매 70% 아세톤 추출물의 항산화능을 측정하였다. 정금나무 열매의 항산화능을 확인하기 위하여 폴리페놀의 함량을 측정, 전자공여능, $ABTS{\cdot}^+$, nitric oxide, hydrogen peroxide들의 소거 측정을 분석하여 다음과 같은 결과를 얻었다. 폴리페놀의 총 함량은 55.972 mg TAE/g로 정량 되었다. 전자공여능 실험에서는 농도 의존적으로 DPPH radical 소거능이 증가 하였으며 500 ${\mu}g/ml$에서 98% 이상의 활성을 나타내어 양성 대조군인 BHA의 활성을 초과하는 것을 알 수 있었다. $ABTS{\cdot}^+$에 대한 소거활성은 500 ${\mu}g/ml$에서 66.7%의 결과로 나타났고, nitric oxide radical 소거능은 100 ${\mu}g/ml$에서 57%의 활성을 나타내었다. 또한 정금나무 열매 70% 아세톤 추출물의 hydrogen peroxide의 소거활성은 50 ${\mu}g/ml$에서 정금나무 열매 추출물은 70% 이상의 활성을 나타났으며, BHA 보다 높은 활성을 나타내었다. 천연물의 산업화 가능성에 있어 가장 중요한 것은 재료의 영속적인 수급과 적은 농도를 첨가하여도 높은 효과를 나타내는지의 여부이다. 매년 수확이 가능한 정금나무 열매를 이용한 본 연구의 결과에서 열매의 항산화능 확인 및 화장품 등 바이오산업에 천연항산화제 원료로서의 적용 가능성을 확인할 수 있었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.380.1-380.1
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• 2016

In this study, we report a novel antioxidant ZnO nanoparticle that is newly designed and prepared by simple surface modification process. Antioxidative functionality is provided by the immobilization of antioxidant of 3,4,5-trihydroxybenzoic acid (galic acid, GA) onto the surface of ZnO nanoparticles. Microstructure and physical properties of the ZnO@GA nanoparticles were investigated by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), infrared spectroscopy (IR) and steady state spectroscopic methods. The antioxidative activity of ZnO@GA was also evaluated using ABTS (3-ethylbenzothiazoline-6-sulfonic acid) radical cation decolorization assay. Notably, ZnO@GA showed strong antioxidative activity in spite of the conjugation process of GA on the ZnO surface. These results provide that GA-coating onto ZnO nanoparticles may offer an intriguing potential for biomedical devices as well as nanomaterials.

• 대한본초학회지
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• 제26권2호
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• pp.67-73
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• 2011

Objectives : The purpose of this research was total polyphenol contents, anti-oxidant activities, anti-inflammatory activities and anti-wrinkle activities of Ulleung islands plants for application as a cosmeceutical ingredients Methods : We were experimented total polyphenol contents, anti-oxidant activities, anti-inflammatory activity and anti-wrinkle activities. Results : In the physiological activities, most Ulleung islands plants is showed the highest anti-oxidant, anti-inflammatory activity in ABTS+ radical cation scavenging activity, hydrogen peroxide($H_2O_2$) scavenging activity, nitric oxide scavenging activity. All experiment of the water and ethanol extract from the Ulleung islands plants ingredients were gradually increased as well. Conclusions : These results suggest that extracts from Ulleung islands plants can be used in natural ingredient in food or cosmetic industry.

• 한국인쇄학회지
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• 제8권1호
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• pp.53-70
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• 1990

It is well known that viologens such as 1.1 - disubstituted 4, 4` - bipyridinium salts and those used as redox indicator, herbicide and electrocheromic display device because those possess the lowest redox potential in any organic system. Viologen salts produced reversible high blue color under the influence of radical cation by photoreduction This study is related to the synthesis of viologen derivatives and the photoreduction property in water solution stats and the polar aprotic polyvinylpyrrolidone(PVP) matrix.

• Bulletin of the Korean Chemical Society
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• 제35권3호
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• pp.851-857
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• 2014

Carotenoids, natural antenna pigments in photosynthesis share a symmetric backbone of conjugated polyenes. Contrary to the symmetric and almost planar geometries of carotenoids, excited state structure and dynamics of carotenoids are exceedingly complex. In this paper, recent infrared and visible transient absorption measurements and excitation dependent dynamics of 8'-apo-${\beta}$-caroten-8'-al and 7',7'-dicyano-7'-apo-${\beta}$-carotene will be reviewed. The recent visible transient absorption measurements of 8'-apo-${\beta}$-caroten-8'-al in polar and nonpolar solvents will also be introduced to emphasize the complex excited-state dynamics and unsolved problems in the $S_2$ and $S_1$ excited states.