• Natural Product Sciences
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• v.6 no.1
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• pp.11-15
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• 2000

Two soyasaponins were isolated from the aerial parts of Astragalus tribuloides Del. Their structures were established on the basis of spectroscopic and chemical methods. In addition, ursolic acid, ${\beta}-sitosterol\;{\beta}-D-glucoside$ and isorhamnetin 3-O-glucoside were isolated and identified by comparing their mp, spectral and chromatographic data with those of authentic samples. This is the first report of screening and isolation of the chemical constituents of this species of genus Astragalus.

• Journal of Korean Library and Information Science Society
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• v.27
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• pp.369-389
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• 1997

KDC(Korea Decimal Classification), which is representative literature classification scheme in Korea, was revised and published in 1996. The purpose of this paper is to suggest a reform measure after detecting out issues and problems associated with the KDC 4th ed. through the result of lecture. The outline of suggestions are as follows : (1) There are not all items of auxiliary tables in relative index. (2) Auxiliary table 2 (Geographic Areas) is not detailed. (3) The manual for the shake of efficient usage is nonexistent and notes are poor in content. (4) Sufficient minimax and alternatives must be setted up for efficiency usage. (5) Some parts of the main schedule are disorder and not logical.

• Journal of Korean Library and Information Science Society
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• v.32 no.3
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• pp.199-226
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• 2001

This study is a part of the serial study on the historical development of cataloging rules in Korea, and focus on 'the period of international standardization'(from 1954 to 1980). In this period, Han-Un Catalog Rules, Dongseo pyeonmoggyujeong(cho), Korean Cataloging Rules 1st ed. and 2nd ed. were published in Korea. This study tries to review the structure and contents of these cataloging rules.

• Archives of Pharmacal Research
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• v.20 no.4
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• pp.342-345
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• 1997

A cytotoxic constituent was isolated by bioassay-guided procedure from the roots of Sophora flavescens Aiton (Leguminosae). The constituent was identified as sophoraflavanone G (I) by means of chemical methods and in comparsion with spectral data of standard compound. The $ED_50$ values of constituent I were 0.78, 1.57, 2.14 and $8.59{\mu}g/ml$ against A549, HeLa, K562 and L1210 cell lines, respectively. Constituent I exhibited highly cytotoxic activities against A549, K562 and HeLa cells, but showed a mild activity $$(ED_50 value, 5{\mu}g/ml)$$ against L1210 cells. Among the tested cell lines, A549 cells were the most sensitive to constituent I.

• YAKHAK HOEJI
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• v.34 no.4
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• pp.262-266
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• 1990

Acetylshikonine, isolated from the root of Lithospermum erythrorhizon showed a strong cytotoxic activity ($ED_{50}=0.10\;ug/ml$) against L1210 cell and T/C = 182% in ICR mice bearing S-180 at a dose of 5 mg/kg. Administrations of 10 mg/kg and 15 mg/kg reduced the T/C values to 60 and 77% respectively. Higher doses reveal toxicity. Seven naphthazarin derivatives synthesized showed good cytotoxic activities against L1210 cell. Especially, naphthazarin and hydronaphthazarin have strong activities ($ED_{50}=0.05\;ug/ml$ for both). Naphthazarin showed a severe toxic effect on ICR mice bearing S-180; no significant toxic effect was observed at a dose of 1 mg/kg or 2 mg/kg, but a severe toxicity (T/C = 23%) by administration of 5 mg/kg. Alkylation of C-2 of naphthazarin is necessary for reducing the toxic effect on ICR mice bearing S-180.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1992.05a
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• pp.44-44
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• 1992

최근 $K^{＋}$ channel openers인 cromakalim과 Pinacidil이 새로운 종류의 혈관확장제로서 항고혈압 치료제로 소개되었다. 그러나 이들 약물의 이완 효과와 새포내 작용기전은 분명치 않다. 따라서 본 연구에서는 개의 관상 동맥에서 얻은 평활근 세포에서 $K^{＋}$ channel openers에 의한 이완의 세포내 기전을 규명하고자 시도하였다 혈관 평할근 세포(dispersed smooth muscle cells)를 collagenase를 이용한 효소소화(enzymatic digestion)에 의해 분리하고, saponin을 이용하여 permeabilize되게 하였다. frypan blue exclusion과 전자 현미경적 관찰에 의하여 세포의 viability를 확인하였다. Dispersed intact cells은 phenylephrine (PE)에 의하여 용량의존 수축반응을 보였고 ED$_{50}$는 2.3 $\times$ $10^{-12}$ M이었다. 이러한 PE에 의한 수축반응은 cromakalim과 pinacidil (ED$_{50}$, 1.2 $\times$ $10^{-12}$ M)의 용량에 의존하여 억제되었다.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1293-1297
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• 2015

This paper introduces the insulation coordination study results for UHV AC systems which was performed by CIGRE working group. The study results will be discussed within IEC technical committee in order to amend the IEC Insulation Coordination 60071-1 Ed. 8 2010 and 60071-2 Ed. 3, 1996. This paper includes the insulation coordination of transformer, gas insulated switchgear, metal oxide arresters and clearances of transmission towers. This article also illustrates the overvoltage specific to UHV systems such as TOV(temporary overvoltage), switching overvoltage, lightning overvoltage and VFTO(very fast transient overvoltage).

• Macromolecular Research
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• v.10 no.1
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• pp.24-33
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• 2002

Interfacial and microfailure properties of carbon fiber/epoxy composites were evaluated using both tensile fragmentation and compressive Broutman tests. A monomeric and two polymeric coupling agents were applied via the electrodeposition (ED) and the dipping applications. A monomeric and a polymeric coupling agent showed significant and comparable improvements in interfacial shear strength (IFSS) compared to the untreated case under both tensile and compressive tests. Typical microfailure modes including cone-shaped fiber break, matrix cracking, and partial interlayer failure were observed under tension, whereas the diagonal slipped failure at both ends of the fractured fiber appeared under compression. Adsorption and shear displacement mechanisms at the interface were described in terms of electrical attraction and primary and secondary bonding forces.

• Archives of Pharmacal Research
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• v.17 no.6
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• pp.420-423
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• 1994

Various N'-substituted anilino-N-methyl-N'-nitrosoureas(2a-n) were easily prepared from the reaction of substituted phenylhydraines $(3, 4-CH_3, {\;} 3-, {\;} 4-OCH_3, {\;} 3-, {\;} 4-F, {\;} 3, {\;} 4-Cl, {\;} 4-Br, {\;} 2-, {\;} 3-, {\;} 4-NO_2, 4-(NO_2)_2)$ with methyl isocyanate, followed by the nitrosation with 99% HCOOH and dry sodium lnitrite powder. Surprisingly, of these series of analogus, the anilino-nitrocosureas substituted with eletron-withdrawing nitro groups (2k-a) showed significantly low $ED_{30}$ values of $1.4-3.4 {\mu}g/ml.$ In addition, none of these copounds subtituted with electron-donating groups exhibited cytotoxicities.

• Bulletin of the Korean Chemical Society
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• v.24 no.4
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• pp.413-420
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• 2003

A gas chromatography/mass spectrometric assay method was developed for the simultaneous determination of neutral and bacis twenty-five disruptors $(ED_S)$ in frog and fish. Afther homogenization and sonication of 5 g of sample, purification was achieves in one step with a solid phase extraction procedure using silica gelflorisl. Eluton was performed with 50mL of acetone : n-hexane (1 : 9) solution. The eluate was concentrated to approximately 10uL and dissolves with 100 uL of hexane and analyzed by GC-MS (SIM). The peaks had good chromatographic properties and the extraction of these compounds from sample also gave relatively high recoveries with small variatoins. Detection limits were 0.1 ng/g for 4-nitrotoluene, benzophenone, hexachlorobenzene, atrazine, malathion, o,p-DDT, o,p-DDT and permethrin, and 0.2 ng/g for heptachlor epoxide, γ-chlordane, α-chlordane, p,p'-DDE, p,p'-DDD, cypermethrin and fenvalerate, and 0.3 ng/g for trifluralin, metribuzin, alachlor, dieldrin and p,p'-DDT, and 0.5 ng/g for heptachlor, aldrin and parathion, and 0.7 ng/g for endrin, and 0.8 ng/g for nitrofen. The recoveries were between 33 and 109%. The method was used to analyze twenty-five frogs and forty-six fishes fishes samples caught from various regions in Korea. Benzophenone was detected at concentration of up to 17.2 ng/g in frog or fish. Heptachlor, aldrin, γ-chlordane, p,p'-DDE, p,p'-DDD, endrin and o,p-DDD were detected at concentrations of 0.7-12.5 ng/g in frog or fish. Also significant leveles of dieldrin (up to 22.5 ng/g) were observed. The developed method may be valuable to be used to the national monitoring project of EDS in biota samples.