• 한국재료학회지
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• 제26권7호
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• pp.393-399
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• 2016

Flower-like nickel oxide (NiO) catalysts were coated on NiCrAl alloy foam using a hydrothermal method. The structural, morphological, and chemical bonding properties of the NiO catalysts coated on the NiCrAl alloy foam were investigated by field-emission scanning electron microscopy, scanning electron microscopy-energy dispersive spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy, respectively. To obtain flower-like morphology of NiO catalysts on the NiCrAl alloy foam, we prepared three different levels of pH of the hydrothermal solution: pH-7.0, pH-10.0, and pH-11.5. The NiO morphology of the pH-7.0 and pH-10.0 samples exhibited a large size plate owing to the slow reaction of the hydroxide ($OH^-$) and nickel ions ($Ni^+$) in lower pH than pH-11.5. Flower-like NiO catalysts (${\sim}4.7{\mu}m-6.6{\mu}m$) were formed owing to the fast reaction of $OH^-$ and $Ni^{2+}$ by increased $OH^-$ concentration at high pH. Thus, the flower-like morphology of NiO catalysts on NiCrAl alloy foam depends strongly on the pH of the hydrothermal solution.

• Preventive Nutrition and Food Science
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• 제10권2호
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• pp.172-178
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• 2005

Dandelions have been reported to have medicinal properties and bioactive components that impact human health. However, the precise biological properties of dandelions and the parts of the plants possessing bioactive components remain uncertain. In this study, we evaluated 3 different types of dandelions based on their cultivation origin (Songpa, Uiryung, and native Uiryung types) as well as their 4 different plant parts (leaf, flower, root, skin). Each sample was extracted with $80\%$ methanol and then compared for the biological activities (anti-oxidative, immune cell proliferative and tumor cell growth inhibitory activities). All 3 types of dandelions possessed a degree of biological functions including the hydroxyl radical scavenger activity, immune cell proliferative activity and tumor cell growth inhibitory activity. However, there was no significant difference in these activities between the 3 dandelion types. Leaves of all three dandelion types showed the highest levels of all biological activities. To a lesser degree, the flower and root parts displayed biological activities. In the skin parts, anti-oxidative activity was also detected only at higher doses of dandelion extracts. Heating the dandelion leaf extract did not affect the biological activity, suggesting a heat-stable nature of the biological compounds. Taken together, these collective data suggest that dandelions, in particular their leaves, possess a high concentration of heat-resistant biological compounds, which are responsible for anti-oxidative, immune cell proliferative and tumor cell growth-inhibitory activities.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권1호
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• pp.16-19
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• 2006

The characteristic of negative differential resistance(NDR) is decreased current when the applied voltage is increased. The NDR is potentially very useful in molecular electronics device schemes. Here, we investigated the NDR characteristic of self-assembled 4,4'-di(ethynylphenyl)-2'-nitro-1-benzenethiolate, which has been well known as a conducting molecule. Self-assembly monolayers(SAMs) were prepared on Au(111), which had been thermally deposited onto $pre-treatment(H_2SO_4:H_2O_2=3:1)$ Si. The Au substrate was exposed to a 1 mM/1 solution of 1-dodecanethiol in ethanol for 24 hours to form a monolayer. After thorough rinsing the sample, it was exposed to a 0.1 ${\mu}M/l$ solution of 4.4'-di(ethynylphenyl)-2'-nitro-1-(thioacetyl)benzene in dimethylformamide(DMF) for 30 min and kept in the dark during immersion to avoid photo-oxidation. After the assembly, the samples were removed from the solutions, rinsed thoroughly with methanol, acetone, and $CH_2Cl_2,$ and finally blown dry with N_2. Under these conditions, we measured electrical properties of self-assembly monolayers(SAMs) using ultra high vacuum scanning tunneling microscopy(UHV-STM). The applied voltages were from -2 V to +2 V with 298 K temperature. The vacuum condition was $6{\time}10^{-8}$ Torr. As a result, we found the NDR voltage of the 4,4'-di(ethynylphenyl)-2'-nitro-1-benzenethiolate were $-1.61{\pm}0.26$ V(negative region) and $1.84{\pm}0.33$ V(positive region). respectively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.1844-1846
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• 2005

The characteristic of negative differential resistance(NDR) is decreased current when the applied voltage is increased. The NDR is potentially very useful in molecular electronics device schemes. Here, we investigated the NDR property of self-assembled 4,4- Di(ethynylphenyl)-2'-nitro-1-(thioacetyl)benzene, which has been well known as a conducting molecule. Self-assembly monolayers(SAMs) were prepared on Au(111), which had been thermally deposited onto pre-treatment$(H_2SO_4:H_2O_2=3:1)$ Si. The Au substrate was exposed to a 1mM/l solution of 1-dodecanethiol in ethanol for 24 hours to form a monolayer. After thorough rinsing the sample, it was exposed to a $0.1{\mu}M/l$ solution of 4,4-Di(ethynylphenyl)-2'-nitro-1-(thioacetyl)benzene in dimethylformamide(DMF) for 30 min and kept in the dark during immersion to avoid photo-oxidation. After the assembly, the samples were removed from the solutions, rinsed thoroughly with methanol, acetone, and $CH_2Cl_2$, and finally blown dry with $N_2$. Under these conditions, we measured electrical properties of self-assembly monolayers(SAMs) using ultra high vacuum scanning tunneling microscopy(UHV-STM). The applied voltages were from -2V to +2V with 299K temperature. The vacuum condition is $6{\times}10^{-8}$ Torr. As a result, we found the NDR voltage of the nitro-benzene is $-1.61{\pm}0.26$ V(negative region) and $1.84{\pm}0.33$ (positive region), respectively.

• 생약학회지
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• 제28권4호
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• pp.198-208
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• 1997

This Study was attempted to investigate the effect of Allium cepa L. (onion) on the activities of GOT and GPT, the levels total lipids, triglyceride, total cholesterol, phospholipid and ${\beta}-lipoprotein$ in the serum and the increase ratio of body and liver weight in the experimentally induced hyperlipemic rats. The activities of S-GOT and S-GPT were significantly decreased in dose of onion juice 3 ml and 5 ml/head as compared to the high lipid-diet control group. The levels of total lipids. Triglyceride, total cholesterol and phospholipids were significantly decreased in dose of onion juice 3 ml and 5 ml/head as compared to the control group, respectively. However, the level of ${\beta}-lipoprotein$ was significantly decreased in dose of onion juice 3 ml/head. The levels of triglyceride and total cholesterol in the liver were significanatly decreased in dose of onion juice 3 ml/head. Increase ratio of the body and liver weight were significantly decreased in dose of onion juice 3 ml/head. Anti-fatigue activity of onion juice were studied in mice using the swimming performance method. The potencies of anti-fatigue acti-vities was significantly found in 1.2 ml/head. p.o. of onion juice. The methanol extract and juice extract of onion was significantly found to have an antioxidative activity on the air oxidation of linoleic acid as compared to the 3-butyl-4-hydroxyanisole and ${\alpha}-tocopherol$.

• 공업화학
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• 제22권2호
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• pp.155-160
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• 2011

동물성유지는 식물성유지에 비해 산화안정성이 뛰어나며, 높은 발열량과 세탄가를 보여 불완전 연소율이 낮다는 장점을 가지고 있으나 포화지방산의 함량이 높고, 원료유지에 불순물 함량이 높아 정제과정이 필요하다는 단점을 가지고 있다. 본 연구에서는 동물성 유지로 폐돈지를 선정하여 초음파에너지를 이용한 전이에스테르화반응의 최적조건을 설정하고자 하였다. 또한 기존공정의 가열 및 교반을 대체할 수 있는 초음파에너지 효과를 확인함으로써 새로운 바이오디젤 제조공정을 제시하고자 하였다. 기존가열방식을 이용한 폐돈지의 전이에스테르화 반응은 $55^{\circ}C$에서 메탄올과 돈지의 반응몰비 12에서 1 h 반응한 경우 가장 우수한 전환특성을 나타내었다. 전이에스테르화 반응에 초음파에너지를 조사할 경우 최적 초음파 조사세기 500 W에서 반응시간을 30 min으로 크게 단축할 수 있었다. 또한 제조된 바이오디젤의 성능평가 결과 점도는 $0{\sim}70^{\circ}C$ 범위에서 1.3~4.0 cP, 발열량은 40.3 MJ/kg으로 바이오디젤 성능기준을 만족하였다.

• Fisheries and Aquatic Sciences
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• 제25권4호
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• pp.189-201
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• 2022

Jellyfish is an emerging aquaculture species, farmed for Oriental cuisines and nutraceutical ingredients. This study aimed to examine antioxidative and antimicrobial potentials of various fractions of the jellyfish, Acromitus hardenbergi. The bell and oral arms of the jellyfish were sequentially extracted with petroleum ether (PE), dichloromethane (DCM), chloroform (CHCl₃), methanol (MeOH), and water (H₂O) to extract its bioactive in an increasing polarity gradient. Test fractions were assayed for antiradical activities using electron spin resonance spectrometry, β-carotene-linoleate model and Folin-Ciocalteu assay; and antimicrobial activity against 2 Gram-negative bacteria, 4 Gram-positive bacteria and 2 fungal species using the disc diffusion assay. All fractions were also subjected to Fourier Transform Infrared (FTIR) analysis to identify types of functional groups present. It was found that the hydrophilic extracts (H₂O fractions) possessed the most effective radical scavenging activity (p < 0.05) while the lipophilic extracts (PE fractions) the most active antimicrobial activity, especially against Gram-positive bacteria (p < 0.05). Total oxidation substrates content was found to be highest in the PE fractions of jellyfish bell and oral arms (p < 0.05). FTIR data showed that the H₂O and MeOH fractions contains similar functional groups including -OH, -C=O, -N-H and -S=O groups, while the PE, DCM, and CHCl₃ fractions, the -CH₃, -COOH groups. This study showed that A. hardenbergi contains antioxidants and antimicrobials, thereby supporting the traditional claim of the jellyfish as an anti-aging and health-promoting functional food. Bioassay-guided fractionation approach serves as a critical milestone for the strategic screening, purification, and elucidation of therapeutically significant actives from jellyfish.

• 한국자원식물학회지
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• 제22권5호
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• pp.403-411
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• 2009

남해안 지역에 자생하고 있는 멀꿀의 이용도를 높이기 위한 기초자료 확보 측면에서 부위별 성분함량과 생리활성을 조사하였다. 비타민 C는 과피에 85.23 mg/100 g, 과육에 61.67 mg/100 g가 함유되어 있었다. 총 아미노산은 과육 434.05 mg/100 g DW에 비해 과피에 762.72 mg/100 g DW으로 많았다. 무기물 함량은 과피(108.48 mg/$\ell$)에 많았으며, K(76.53 mg/$\ell$), Ca(20.20 mg/$\ell$) 및 Mg(6.22 mg/$\ell$)가 대부분을 차지했다. 메탄올 추출물 1,000 mg/$\ell$일 때 총 페놀화합물은 7.3-9.6 mg/$\ell$였으며, 총 플라보노이드 함량은 5.1-6.7 mg/$\ell$였다. 멀꿀 메탄올 추출물 4,000 mg/$\ell$의 아질산염소거는 과피와 과육은 각각 79.5, 77.8% 인데 비해 종자는 17.1%였으며, tyrosinase 활성의 저해효과는 10.8%이하를 나타냈다. 항균활성은 그람양성균과 그람음성균 모두 과피 메탄올 추출물의 저 농도에서는 나타나지 않은 경우도 있었으나 과육과 종자 추출물에서는 저해환 직경이 $8.91{\sim}12.25\;mm$을 나타냈다.

• 한국약용작물학회지
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• 제8권1호
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• pp.1-8
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• 2000

톱풀 Achillea sibirica Ledeb. (Compositae: 국화과)은 국내 산지의 초원에 널리 분포하는 흰색꽃이 피는 다년생 초본으로 민간에서 봄의 어린 순을 나물로 먹고 전초와 종자를 말린 것(신초;神草) 을 , 건위(健胃), 강장(彈壯), 해열(解熱), 진경(鎭湮), 진통(鎭痛), 정기증진 (精氣增進), 출혈이 심한 치질에 사용해 왔다. 천연물로부터의 우수한 항산화제의 개발의 일환으로 이 식물의 전초의 MeOH extract와 그것의 Hexane fraction., Methyene Chloride fraction., Ethyl Acetate fraction, Butanol fration 에 대해 DPPH radical 소거 효과에 의한 검색을 실시한 결과 EtOAc 분획에서 우수한 항산화 활성을 나타내어 그 EtOAc 용매분획층을 column chromatography 하여 2종의 flavonoid glycoside (E-1,2) 를 분리하였으며, hexane분획에서의 1종의 sterol 화합물 (H-1)과 더불어 각종 이화학적 성상과 spectral data로부터 구조를 동정한 결과 각각 sterol mixture (H-1), kaempferol-3-O-glucoside(E-1), luteolin-7-O- neohesperidoside(E-2)로 확정하였고, 그 중 화합 H-1은 campesterol, stigmasterol, ${\beta}-sitosterol$이 혼합되어 있음을 확인하였다. 화합물 E-1, 2에 대해 항산화 활성 검색을 실시하여, DPPH radical 소거 효과에 의한 검색에서 각각 $12.5{\mu}g/ml$과 $15.4{\mu}g/ml$에서 EC50을 나타내어 항산화 효과를 보였고, TBA에 의한 비색정량법에 의한 항산화 활성 검색에도 항산화 효과를 보였다.

• Nutrition Research and Practice
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• 제8권5호
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• pp.509-515
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• 2014

BACKGROUND/OBJECTIVES: The root of Vitis amurensis Ruprecht, a sort of wild-growing grape, has been used in oriental medicine for treatment of skin ailments; however, its dermatological activity is not sufficiently understood. The aim of this study was to investigate tyrosinase inhibitory and anti-melanogenic activities of V. amurensis Ruprecht root methanol extract (VARM) in B16F10 mouse melanoma cells and to attempt to isolate and identify the active compound issued from VARM. MATERIALS/METHODS: Anti-melanogenic activity of VARM was analyzed in ${\alpha}$-melanocyte stimulating hormone (MSH)-stimulated B16F10 cells through evaluation of antioxidative activity as well as inhibited tyrosinase activity and melanin contents compared with those of kojic acid and arbutin. After anti-melanogenic analysis of VARM, serial fractionation, nuclear magnetic resonance (NMR), and thin layer chromatorgraphy (TLC) were applied for identification of active compounds contained in VARM. RESULTS: VARM significantly inhibited oxidative stress and tyrosinase activity and attenuated ${\alpha}$-MSH-induced melanin production in B16F10 cells. For isolation of active compounds, VARM was fractionated using a series of organic solvents, including dichloromethane ($CH_2Cl_2$), ethyl acetate (EtOAc), and n-butanol (n-BuOH). Among fractions showing anti-melanogenic activity, the CH2Cl2 fraction induced the most potent attenuation of melanogenesis without cytotoxicity and the major compound in the $CH_2Cl_2$ fraction was identified as betulinic acid. Betulinic acid isolated from the $CH_2Cl_2$ fraction of VARM significantly attenuated ${\alpha}$-MSH-induced melanogenesis in a dose dependent manner, which was stronger than that of arbutin used as a positive control. CONCLUSIONS: These results indicate that VARM inhibits oxidative stress, tyrosinase activity, and ${\alpha}$-MSH-induced melanogenesis in B16F10 cells, due primarily to the active compound, betulinic acid, in the $CH_2Cl_2$ fraction.