• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.343-343
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• 2010

Tetra(4-carboxyphenyl)porphine(TCPP) 흡착으로부터 그래핀 표면의 기능화에 대하여 방사광을 이용한 광전자 분광법으로 연구하였다. 최근 들어 그래핀을 이용한 소자개발에 있어서 그래핀의 우수한 전기적 특성을 저해하지 않으며 그 표면의 화학적 활성도를 개선하고자 하는 필요성이 대두되고 있다. 따라서 기능성 작용기를 가지고 있는 유기반도체 물질을 이용하여 그래핀 표면의 화학적 활성화를 촉진시킴과 동시에 보호층을 형성시키고자 하는 연구가 보고되고 있다. 그러나 일반적으로 그 유기분자들이 그래핀 표면에 흡착되었을 때 전하의 이동을 유도함으로서 원래 그래핀의 물리적 특성을 변화시킬 가능성을 가지고 있다. 본 연구에서는 6H-SiC 표면 위에 두층으로 에피텍셜 성장된 그래핀에 TCPP 분자를 흡착시킴으로서 그래핀의 고유 특성을 거의 저해하지 않음과 동시에 기능성 작용기의 역할을 충실히 수행할 수 있음을 보여 주고 있다. 이는 valence band dispersion과 일함수 변화 측정으로 관찰할 수 있었다. 또한 TMA를 이용한 TCPP의 수산화 작용기의 반응 과정은 일반적인 실리콘 산화막에 적용했을 때 일어나는 화학적 반응 과정과 다른 메커니즘으로 진행됨을 관찰하였다.

• Journal of Adhesion and Interface
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• v.20 no.1
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• pp.1-8
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• 2019

Fabrication of monolayer is important method for enhancing physical and chemical characteristics such as light shielding and antireflection while maintaining thin film properties. In previous studies, monolayers were fabricated by various methods on small substrates, but processes were complicated and difficult to form monolayers with large area. We used rod coating equipment with a small amount of coating liquid to form a HCP (hexagonal closed packing) coating of PMMA beads on PET(poly(ethylene terephthalate)) substrate with $20cm{\times}20cm$ size. We observed that changes in morphologies of monolayers by using the solvents with different boiling points and vapor pressures, by adapting surfactants on particles and by applying plasma treatment on substrates. The coverage was increased by 20% by optimizing the coating conditions including meniscus of beads, control of the attraction - repulsion forces and surface energy. This result can potentially be applied to optical films and sensors because it is possible to make a uniform and large-scale monolayer in a simple and rapid manner when it is compared to the methods in previous studies.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.6
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• pp.656-660
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• 2001

Gametogenesis, the reproductive cycle, and the condition index of the soft clam, Mya arenaria were investigated monthly based on histological observation at Sachon Bay, south coast of Korea from May 1998 to September 1999 . M. arenaria is dioceious. The ovary and testis were composed of a number of ovarian sacs and testicular tubules, respectively. Ripe oocytes were characterized by germinal vesicles with nucleoli, and their sizes about $60{\mu}m$ in diameter. Monthly changes in condition index and water temperature were closely related to the annual reproductive cycle. The reproductive cycle can be classified into 5 stages: early active stage (february to March), late active stage (April to August), ripe stage (September), partially spawned and spent stage (September to October), inactive stage (November and January).

• Korean Journal of Food Science and Technology
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• v.33 no.6
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• pp.760-763
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• 2001

To develop a functional beverage from Korean cherry (Prunus tomentosa Thunberg), inhibition effect of ethanol extract and juice of the korean cherry on melanin systhesis and tyrosinase activity in vitro was investigated. Inhibition ratio of tyrosinase activity increased as the concentration of solid of korean cherry juice increased, and inhibition affect was high in initiation step of enzyme reaction and then gradually decreased. Inhibition ratio of tyrosinase activity was high in the 70% (v/v) ethanol extract of the cherry and the highest in the ethyl acetate fraction of the 70% (v/v) ethanol extract. Ultimatly, the amounts of functional matter (melanin synthesis inhibitor) in the cherry was highest in ethyl acetate fraction of the ethanol extract.

• Food Science and Preservation
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• v.9 no.2
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• pp.228-233
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• 2002

In order to exploit as a new functional decocted beverage, chemical components, antioxidative and antimicrobial activities young stems of mulberry(Morus alba) were surveyed. The proximate composition was composed of crude fiber 51.12%, ash 13.46%, total sugar 10.38%, crude fat 9.10% and crude protein 5.01%. The P(295.9 mg%) was the highest mineral found in young stem of mulberry and Ca 289.6 mg%, K 209.6 mg%, Na 58.3 mg%, Mg 45.0 mg% and Fe 4.6 mg% in that order. Free sugars was composed of glucose 1.08%, galactose 022%, sucrose 0.20% and fructose 0.16%. Eight fatty acids in stem of mulberry were identified and the major fatty acids were linoleic acid(46.10%), palmitic acid(27.84%) and linolenic acid(10.85%). Among the 17 amino acids detected, total amino acid was 2,450.5 mg% and proline(313.7 mg%) was the most predominant. Methanol extract and ethyl acetate fraction showed stronger activity of the hydrogen donating activities, each of 77.24% and 80.08%, respectively. The methanol extract from young stem of mulberry showed the strongest antimicrobial activities to Bacillus subtitis and Bacitus cereus. Chloroform and ethyl acetate fractions from methanol extract of young stem showed a inhibition zone of 9.0∼19.0 ㎜ in diameter against pathogen bacteria.

• Journal of Dairy Science and Biotechnology
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• v.31 no.2
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• pp.187-194
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• 2013

This study was carried out to investigate the quality characteristics and antioxidant activity of fermented milk containing mushroom (Phellinus baumii, Ganoderma lucidum, and Lentinus edodes) extracts. As the ratio of the mushroom extract increased, the pH of the fermented milk decreased proportionally and titratable acidities increased significantly. The number of lactic acid producing bacteria was the highest in the fermented milk sample containing 1.0% Lentinus edodes extract. The DPPH and ABTS radical scavenging activities of the fermented milk containing mushroom extracts were higher than that of the controls. The quality characteristics, such as pH, titratable acidity, and the number of lactic acid producing bacteria were not remarkably different between the milk samples subjected to treatments with and without the addition of mushroom extracts during the storage period. From the sensory evaluation of the fermented milk samples containing mushroom extracts, the color, flavor, taste, texture, and overall acceptability of the fermented milk sample containing 1.0% Lentinus edodes extract was found to be considerably better than those of the other groups. In conclusion, the present study indicated that the fermented milk containing mushroom extracts could be used as a functional antioxidant containing food.

• Food Science and Preservation
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• v.22 no.2
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• pp.275-280
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• 2015

Among the naturally occurring antioxidants, polyphenols are widely distributed in various fruits, vegetables, wines, juices, and plant-based dietary sources and divided into several subclasses that included phenolic acid, flavonoids, stilbenes, and lignans. As part of our continuing search for bioactive food ingredients, the antioxidant and ${\alpha}$-glucosidase inhibitory activities of the aqueous ethanolic extract from the aerial parts of Ainsliaea acerifolia were investigated in vitro. The antioxidant properties were evaluated via radical scavenging assays using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) ($ABTS^+$) radicals. In addition, the anti-diabetic effect of A. acerifolia extracts was tested via ${\alpha}$-glucosidase inhibitory assay. Furthermore, the total phenolic contents were determined using a spectrophotometric method. All the tested samples showed dose-dependent radical scavenging and ${\alpha}$-glucosidase inhibitory activities. In particularly, the ${\alpha}$-glucosidase inhibitory and radical scavenging properties of the ethyl acetate (EtOAc)-soluble portion from the aerial parts of the A. acerifolia were higher than those of the other solvent-soluble portions. These results suggest that A. acerifolia could be considered a new potential source of natural antioxidants and antidiabetic ingredients. More systematic investigation of the aerial parts of A. acerifolia will be performed for the further development of anti-oxidative and antidiabetic drugs.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.2
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• pp.228-238
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• 2007

This study was conducted to increase sweetpotato utilization and to determine the vegetative value of sweetpotato tips by investigating the phenolic compounds, antioxidative effect in oil, electron donating ability, nitrite scavenging effect and ACE inhibition activities. The phenolic compounds present in sweetpotato tips are the gallic, chlorogenic, gentisic, caffeic, couramic and ferulic acid, which are 16-122 times higher compared to other vegetables such as spinach, soybean sprout, and perilla leaves. In each solvent extract, the total phenolic compounds (175.8mg/g) was composed of 55% EtOAc extraction and 39% BuOH extract, respectively. The results of induction period using the Rancimat method showed that the antioxidant activity of SP tips was higher than the tocopherol or BHT. The relative levels of each solvent extract in SP tips were as follows: EtOAc>BHT>BuOH>Tocopherol>Water>$CHCl_3$>Hexane. The peroxide value was measured every 5 days for 25 days during storage and results showed that the peroxide value, the tips, tuberous root and tocopherol were lower compared to spinach, soybean sprout and perilla leaves. Nitrite scavenging effects were excellent in sweetpotato tips, perilla leaves and soybean sprout, especially, inhibition rate of perilla leaves (72%) were superior to the others. In process of solvent extraction, activity of BuOH and water extractions were the best. ACE inhibition activity in sweetpotato tips was 1.5 times higher than in tuberous roots and $1.9{\sim}3.7$ times higher than in spinach, soybean sprout, perilla leaves.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.4
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• pp.411-420
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• 2007

This study was conducted to increase sweetpotato utilization and to determine the vegetative value of sweetpotato tips by investigating the phenolic compounds, antioxidative effect in oil, electron donating ability, nitrite scavenging effect and ACE inhibition activities. The phenolic compounds present in sweetpotato tips are the gallic, chlorogenic, gentisic, caffeic, couramic and ferulic acid, which are 16-122 times higher compared to other vegetables such as spinach, soybean sprout, and perilla leaves. In each solvent extract, the total phenolic compounds(175.8 mg/g) was composed of 55% EtOAc extraction and 39% BuOH extract, respectively. The results of induction period using the Rancimat method showed that the antioxidant activity of SP tips was higher than the tocopherol or BHT. The relative levels of each solvent extract in SP tips were as follows: EtOAc>BHT>BuOH>Tocopherol>Water>$CHCl_3$>Hexane. The peroxide value was measured every 5 days for 25 days during storage and results showed that the peroxide value, the tips, tuberous root and tocopherol were lower compared to spinach, soybean sprout and perilla leaves. Nitrite scavenging effects were excellent in sweetpotato tips, perilla leaves and soybean sprout, especially, inhibition rate of perilla leaves(72%) were superior to the others. In process of solvent extraction, activity of BuOH and water extractions were the best. ACE inhibition activity in sweetpotato tips was 1.5 times higher than in tuberous roots and $1.9{\sim}3.7$ times higher than in spinach, soybean sprout, perilla leaves.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.4
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• pp.608-614
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• 2013

We investigated the anti-wrinkle activity of an 80% ethanol extract of Curdrania tricuspidata leaves (CTL80) on ultraviolet-induced photoaging in hairless mice. Skin wrinkles were induced by 10 weeks of UVB-irradiation on the back of Skh-1 hairless mice three times a week. Mice were divided into ten groups; normal control (-UVB), UVB irradiated control group (+UVB), dietary groups (UVB+ascorbic acid 0.1%, UVB+CTL80 0.1%, UVB+CTL80 0.25%) and topical application groups (-UVB+base lotion (BL), UVB+BL, UVB+ascorbic acid 1%+BL, UVB+CTL80 1%+BL, UVB+CTL80 2%+BL). Wrinkle formation, histological changes, superoxide dismutase (SOD) activities, glutathione peroxidase (GSH-Px), and the expression of matrix metalloproteinases (MMP-1, MMP-3 and MMP-9) were analyzed. Wrinkles for the +UVB groups formed as a pattern of deep furrows and thick crests. Wrinkles with CTL80 treatment formed as a pattern of shallow furrows and thin crests, with wrinkle areas were lower than the +UVB group. In an antioxidant analysis of mouse blood, SOD and GSH-Px activities were significantly higher in the CTL80 topical application group compared to the +UVB group. The mRNA expression of MMPs in the +UVB group was significantly higher than the normal control group, and significantly lower in the CTL80-treated group. In conclusion, CTL80 exerted anti-wrinkle activity on ultraviolet-induced photoaging by regulating antioxidative defense systems and MMPs expression.