• 한국조명전기설비학회지:조명전기설비
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• 제1권2호
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• pp.62-69
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• 1987

이 논문은 Phenolic 수지의 Tracking파괴의 CTI에 관한 고찰로써 전극재료의 일부가 누설재료에 의하여 침식되기 때문에 tracking파괴를 증진시키며 다음과 같은 영향을 받는다. $\circled1$절연재료에서는 C. T. I의 값이 350정도에서는 현재까지 규정하고 있는 백금전극보다도 황동전극이 더욱 근사한 값을 얻을 수 있었다. $\circled2$C. T. I의 값은 전해액의 저항율과는 무관하다. $\circled3$시요표면의 접촉각이 증가함에 따라 Corona 개시전압과 C. T. I의 값은 증가한다.

• Preventive Nutrition and Food Science
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• 제15권1호
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• pp.36-43
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• 2010

The purpose of this study was to investigate the phenolic acid, proanthocyanidin (PAs), and flavonol glycoside contents, as well as the antioxidant activities of pine needle extracts from six species of young pine trees. The extracts were prepared from Section Pinus (Diploxylon): P. densiflora, P. sylvestris, P. pinaster and P. pinea, and Section Strobus (Haploxylon): P. koraiensis and P. strobus. Phenolics were extracted from pine needles with 80% acetone to obtain the soluble free fraction, and insoluble residues were digested with 4 M NaOH to obtain bound ethyl acetate and bound water fractions. Phenolics were analyzed by HPLC, and the hydrophilic antioxidant activity was measured using oxygen radical absorbance capacity (ORAC). Total phenolic and flavonoid contents of the soluble free fraction were higher than those of the bound ethyl acetate and bound water fractions. The main phenolics were monomers and polymers of PAs in the soluble free fraction, and phenolic acids and flavonol glycosides in bound ethyl acetate fraction. Flavonol glycosides found in different species of pine needles were qualitatively similar within fractions, but composition varied among Pinus sections. High levels of kaempferol arabinoside and an unknown compound were present in all Strobus species. The soluble free fraction had the highest antioxidant activity, followed by bound ethyl acetate and bound water fractions.

• 공업화학
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• 제9권2호
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• pp.238-242
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• 1998

복합체 제조의 최적조건을 얻기 위해 페놀수지와 목분의 함량을 변화시켜 제조하고 그들의 기계적 성질을 측정하였다. 페놀수지의 함량이 45 wt%일 때 가장 높은 기계적 강도를 나타내었다. 또한 페놀수지와 목분 복합체의 기계적 성질을 개선하기 위해 페놀수지의 개질제로서 폴리우레탄을 사용하였다. Isocyanate 작용기를 갖는 폴리우레탄은 페놀수지와 잘 혼합되지 않기 때문에 상용성을 개선하기 위해 페놀 blocked 폴리우레탄을 합성하였다. 이들을 첨가한 복합체는 개질제 함량이 5 wt%에서 최대의 기계적 강도를 나타냈다. 또한 $210^{\circ}C$에서 경화된 복합체의 기계적 강도가 $150^{\circ}C$에서 경화된 것보다 우수하였다.

• Environmental Engineering Research
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• 제13권4호
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• pp.216-223
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• 2008

An efficient method for the simultaneous determination of eleven phenolic endocrine-disrupting chemicals (EDCs) present in wastewater influent samples was described. The 11 phenolic EDCs including alkylphenols, chlorophenols, and bisphenol A were determined by gas chromatography/mass spectrometry-selected ion monitoring (GC/MS-SIM) following two work-up methods for comparison; isobutoxycarbonyl (isoBOC) derivatization and tert-butyldimethylsilyl (TBDMS) derivatization. The wastewater influent samples containing the 11 EDCs were adjusted to pH 2 with $H_2SO_4$ and then cleaned up with n-hexane. Next, they were subjected to solid-phase extraction (SPE) with XAD-4 resin and subsequently converted to isoBOC or TBDMS derivatives for sensitivity analysis with gas chromatography/mass spectrometry-selected ion monitoring (GC/MSSIM). Following isoBOC derivatization and TBDMS derivatization, the recoveries were 86.6-105.2% and 97.6-142.7%, the limits of quantitation (LOQ) for the 11 phenolic EDCs for SIM was 0.001-0.050 ng/mL and 0.003-0.050 ng/mL, and the SIM responses were linear with the correlation coefficient varying by 0.9717-0.9995 and 0.9842-0.9980, respectively. When these methods were applied to five selected wastewater influent samples, for isoBOC derivatization and TBDMS derivatization the ranges of concentration detected were 0.2-99.6 ng/mL and 0.4-147.4 ng/mL, respectively.

• Applied Biological Chemistry
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• 제36권3호
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• pp.154-157
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• 1993

탈지 산사(Crataegus pinnatifida Bunge)에서 추출된 에테르 추출물의 항산화성이 확인됨에 따라, 각 페놀성 추출물, 즉 유리형, 용성 에스테르형 및 불용성 물질의 분리 및 동정이 TLC, gel column chromatography, MS 및 H-NMR에 의해서 시도되었다. 시료의 유리형 페놀산 추출물에서는 caffeic acid, protocatechuic acid 및 pyrogallol, 용성 에스테르형 페놀에서는 caffeic acid 및 phloroglucinol, 불용성 페놀산에서는 protocatechuic acid, phloroglucinol 등이 각각 동정되어 산사의 주된 항산화성 물질임이 확인되었다.

• Macromolecular Research
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• 제15권6호
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• pp.565-574
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• 2007

In this study, five representative, commercially available polymers, Ultem 1000 polyetherimide, Kapton polyimide, phenolic resin, polyacrylonitrile and cellulose acetate, were used to prepare pyrolyzed polymer membranes coated on a porous {\alpha}-alumina$ tube via inert pyrolysis for gas separation. Pyrolysis conditions (i.e., final temperature and thermal dwell time) of each polymer were determined using a thermogravimetric method coupled with real-time mass spectroscopy. The surface area and pore size distribution of the pyrolyzed materials derived from the polymers were estimated from the nitrogen adsorption/desorption isotherms. Pyrolyzed membranes from polymer precursors exhibited type I sorption behavior except cellulose acetate (type IV). The gas permeation of the carbon/{\alpha}-alumina$ tubular membranes was characterized using four gases: helium, carbon dioxide, oxygen and nitrogen. The polyetherimide, polyimide, and phenolic resin pyrolyzed polymer membranes showed typical molecular sieving gas permeation behavior, while membranes from polyacrylonitrile and cellulose acetate exhibited intermediate behavior between Knudsen diffusion and molecular sieving. Pyrolyzed membranes with molecular sieving behavior (e.g., polyetherimide, polyimide, and phenolic resin) had a $CO_2/N_2$ selectivity of greater than 15; however, the membranes from polyacrylonitrile and cellulose acetate with intermediate gas transport behavior had a selectivity slightly greater than unity due to their large pore size.

• 한국자원식물학회지
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• 제23권6호
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• pp.487-497
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• 2010

ROS have been associated with pathogenic processes including carcinogenesis through direct effect on DNA and play an important role in the pathogenesis of inflammation. Because of many types of phenolic acid derivatives and flavonoids, apples have been one of the human diet since ancient times and are one of the most commonly consumed fruits in worldwide. In this study, catechin, chlorogenic acid and phlorizin dihydrate were purified and identified by HPLC and GC/MS. The contents of catechin, chlorogenic acid and phlorizin dihydrate were 1.01 mg, 7.01 mg and 3.67 mg/ kg wet weight, respectively. Catechin and phlorizin dihydrate were found to significantly inhibit oxidative DNA damage, while chlorogenic did not affect. Also, catechin inhibits NO and $PGE_2$ production via suppressing iNOS and COX-2 expression. However, chlorogenic acid and phlorizin dihydrate did not affect. Our results show that catechin may be the most active phenolic compound in anti-oxidative damage and anti-inflammatory effect.

• Toxicological Research
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• 제19권1호
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• pp.45-50
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• 2003

The purpose of this study was to determine the role of substituted groups in phenolic compounds to develop an anticancer agent having strong cytotoxicity against cancer cells but weak against normal cells. The phenolic compounds used in this study were gallic acid and ferulic acid with hydroxyl and carboxyl groups, syringic acid with hydroxyl, carboxyl and methoxy groups, and pyre-gallol with hydroxyl groups. Cytotoxicities of these compounds were evaluated by MTT assay for cell viability and XTT assay for cell adhesion activity in normal human skin fibroblast (Detroit 551) and human skin melanoma (SK-MEL-3) cells. Syringic acid, gallic acid and ferulic acid decreased the cell viability and cell adhesion activity in SK-MEL-3 cells but not in Detroit 551 cells while pyrogallol decreased in both cells. The susceptibility of cell viability based on the $IC_{50}$ values of MTT assay in Detroit 551 cells was in the following order: pyrogallol > gallic acid > ferulic acid > syringic acid, while it was in SK-MEL-3 cells: Syringic acid > progallol > ferulic acid > gallic acid. These results suggest that carboxyl and methoxy groups of these compounds play an important role in selectivity of cytotoxicity in normal and cancer cells.

• Natural Product Sciences
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• 제20권4호
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• pp.269-273
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• 2014

Activity guided phytochemical examination of the rhizome of Phragmites communis has led to the isolation of two phenolic acids and two lignans. Structures of these compounds were elucidated as methyl gallate (1), ${\rho}$ -hydroxy cinnamic acid (2), (+) -lyoniresinol (3), (+)-lyoniresinol-9'-O-${\beta}$-D-glucopyranoside (4) by comparisons with previously reported spectral data. To investigate the melanogenesis inhibitory effects of these compounds, the melanin level and tyrosinase activity were examined in B16F10 melanoma cell. Each compound inhibited both tyrosinase activity and melanin synthesis compared with positive control, kojic acid and arbutin. These results suggest that the phenolic compounds from Phragmites communis might be developed as a potent skin whitenting cosmeceuticals.

• Asian Pacific Journal of Cancer Prevention
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• 제14권11호
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• pp.6991-6995
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• 2013

Antioxidant activity, total phenolic, total flavonoid compounds and cytotoxicity to cancer cell lines of propolis extracts from two extraction methods were investigated in this study. Propolis was collected from Phayao province and extracted with 70% ethanol using maceration and sonication techniques. The antioxidant activity was evaluated by DPPH assay. Total phenolic and flavonoid compounds were also determined. Moreover, the cytotoxicity of propolis was evaluated using MTT assay. The percentage propolis yield after extraction using maceration (18.1%) was higher than using sonication (15.7%). Nevertheless, antioxidant and flavonoid compounds of the sonication propolis extract were significant greater than using maceration. Propolis extract from sonication showed antioxidant activity by $3.30{\pm}0.15$ mg gallic acid equivalents/g extract. Total phenolic compound was $18.3{\pm}3.30$ mg gallic acid equivalents/g extract and flavonoid compound was $20.49{\pm}0.62$ mg quercetin/g extract. Additionally, propolis extracts from two extraction methods demonstrated the inhibitory effect on proliferation of A549 and HeLa cancer cell lines at 24, 48 and 72 hours in a dose-dependent manner. These results are of interest for the selection of the most appropriate method for preparation of propolis extracts as potential antioxidant and anticancer agents.