• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.56.1-56.1
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• 2016

Surface mineralogy of asteroids are inferred from photometric and spectroscopic observations with the wide range of wavelengths spanning from far-ultraviolet to mid-infrared. We classify mineralogy of those objects based on their spectral absorption features and spectral slopes. Based on overall spectral shapes, mineralogical classes are divided into three broad complexes; silicates (S), carbonaceous (C) and Vestoids (V), and the end-members that do not fit within the S, C and V broad-complexes. Each of them is subdivided into individual classes. Spectral classification of asteroidal objects has been simply represented by a combination of photometric colors. For a decade, photometric data of asteroids have been grouped and classified according to their SDSS colors converted from the spectral taxonomy. However, systematic studies for asteroid taxonomy based on Johnson-Cousins filters is few, and were conducted only with a small number of objects. In this paper, we present our preliminary results for taxonomic classification of Main Belt asteroids based on KMTNet Johnson-Cousins photometric color system.

• Bulletin of the Korean Chemical Society
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• v.25 no.10
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• pp.1559-1563
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• 2004

The topoisomerase II poisoning effect of certain protoberberine alkaloids is associated with anti-cancer activity. Structure-activity relationships of protoberberine analogues substituted on the ring protons reveal that substitution at the C19 position is an important determinant of biological activity. In this study, the effects of substituent modification at the C19 position on the interaction of protoberberines with DNA are determined using UV and NMR spectroscopy. The line broadening effect on aliphatic resonances, chemical shift changes of the imino protons of HP14 upon berberine and berberrubine binding to HP14, and the rate of the exchange process between protoberberine analogs bound indicate that berberrubine binds HP14 more specifically than berberine. In addition, the free HP14 is altered by the substituent at the 19-position. UV spectra of berberrubine have shown a hypochromic effect together with a slight red shift, which are usually regarded as characteristics of DNA intercalation. These results are consistent with our previous report that the berberrubine is partially intercalated with HP14 with molar ratio 1 : 1, whereas a non-specific interaction is predominant between the berberine and HP14.

• YAKHAK HOEJI
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• v.41 no.6
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• pp.709-713
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• 1997

For the investigation of bioactive natural products with hypoglycemic effect, we have evaluated various extracts of Pulsatillae Radix(Ranunculaceae), which has been used in traditional medicine for hematochezia due to intense evil heat, malaria, chills and fever, epistaxis and internal hemorrhoids. The ethylacetate extract of the radix of this plant was found to show a significant hypoglycemic effect on alloxan diabetogenic mice. Using bioactivity-guided chromatographic purification of the ethylacetate extract, hypoglycemic constituent: 2${\beta}$, 3${\beta}$, 14${\alpha}$, 20, 22R, 25-hexahydroxy-cholest-7-en-6-one was isolated and structurally identified by physico-chemical properties and spectroscopic evidences.

• YAKHAK HOEJI
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• v.41 no.6
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• pp.704-708
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• 1997

In our search for bioactive natural products with antitumor activity, we have valuated various extracts of Saururi Herba (Saururaceae), which has been used in traditional medici ne for edema, beriberi, jaundice, turbid urine, carbuncle and furuncle. The hexane extract of the aerial part of this plant was found to show a potent cytotoxicity against several kinds of cultured human solid tumor cell lines (AGS, A549, HCT15, SKOV3, HEP-3B) in vitro. Using cytotoxicity-guided chromatographic separation of the hexane extract, cytotoxic constituent: 10-aminomethyl-3-hydroxy-4-methoxyphenanthrene-carboxylic acid lactam, was isolated and structurally identified by physico-chemical properties and spectroscopic evidences.

• Archives of Pharmacal Research
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• v.20 no.3
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• pp.291-296
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• 1997

The studies were carried out to evaluate the constituents in the aerial part of Isodon excisus var. coreanus (Labiatae). From the aqueous fraction of methanol extract, compound I (${\alpha}$-[[3-(3, 4-dihydroxyphenyl)-1-oxo-2-propenyl]oxy]-3,4-dihydroxy-benzenepropanoic acid), compound II (9-methyl-dihydroferulic acid-4-O-.betha.-D-glucopyranosyl $(1{\rightarrow}2)$-${\alpha}$-L- rhamnopyranosyl (1.rarw.4)-.betha.-D-glucopyranoside), compound III (ent-7.alpha., 11${\alpha}$,15.betha.-trihydroxy-kaur-16-en-1-O-.betha.-D-glucopyranoside) and compound IV ($2{\alpha}$,3${\beta}$,$7{\alpha}$,23-tetrahydroxy-olean-12 -en-28-oic acid 28-O-${\beta}$-D-glucopyranoside) were isolated and identified on the basis of their physicochemical and spectroscopic evidences[IR, FAB(-)MS,$^{1}H-NMR,$$^{13}C-NMR,$$ HMQC$$^{1}H-^{1}H $COSY and HMBC (Heteronuclear Multiple Bond Connectivity)]. Especially, New compounds II and III were named Isodonin A and Isodonin B respectively.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.83.2-83.2
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• 2012

Type I AGNs are classified by the presence of broad emission lines while Type II AGNs show narrow emission lines only. All-sky surveys such as SDSS provide large AGN samples for statistical studies. However, the AGN samples suffer selection bias due to the incomplete selection criteria. To investigate the missing Type I AGNs in optical spectroscopic surveys, we start with a sample of SDSS Type II AGNs at 0.02 < z < 0.05, using the MPA-JHU SDSS DR7 catalog. We search for the hidden broad $H{\alpha}$ component with both visual inspection and the multi-component spectral decomposition method. Out of 1383 Type II AGNs, we find a total of 62 missing Type I AGNs (~4.5%). The sample has mean black hole mass, log $(M_{BH}/M_{SUN))=6.48{\pm}0.53$, and luminosity, log $(L_{H{\alpha}}/ergs^{-1})=40.52{\pm}0.33$, with Eddington ratio, log $(L_{bol}/L_{Edd})=-1.51{\pm}0.41$. We will describe the sample and present the $M_{BH}-{\sigma}_*$, and $M_{BH}-M_*$ relations of the sample in the context of the BH-galaxy coevolution.

• Journal of the Korean Chemical Society
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• v.29 no.3
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• pp.226-232
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• 1985

Dioxomolybdenum(VI) complexes, MoO$_2$(H-Sal-R)$_2$, R; arylamines, have been synthesized by reactions of dioxobis (salicylaldehydato) molybdenum(VI) with various primary amines. These complexes have been characterized by electric conductivity and spectroscopic studies. Infrared, uv-vis, and proton nmr spectra show that the complexes are six-coordinated with cis-MoO$_2$ group. And mass spectra indicates that the combining ratios for Mo (VI)-ligand are 1 : 2. They are yellow, stable for a considerably long time in the atmosphere at room temperature and slightly soluble in alcohol, dichloromethane and dimethylformamide but insoluble in benzene, ether and carbon tetrachloride.

• Journal of the Korean Chemical Society
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• v.24 no.2
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• pp.121-128
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• 1980

Isonitrosobenzoylacetone is particularly interesting, as the isonitroso group has two potentially coordinating sites which can compete with the cabonyl groups in forming bonds with the metal ions. In this paper tris(isonitrosobenzoylacetonato)cobalt(III) and bis(isonitrosobenzoylacetonato)palladium(II) have been prepared, and their structures have been investigated. Spectroscopic studies lead to the conclusion that the both complexes do not contain an OH group in the chelated five-membered ring structure in which the ligand coordinates to metal through oxygen of the acetyl group and nitrogen of the isonitroso group. The coordination manner of this ligand is similar to that of isonitrosobenzoylacetone obtained by Patel and Haldar.

• Journal of Pharmaceutical Investigation
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• v.27 no.2
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• pp.125-131
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• 1997

Ethoxycarbonyloxyethyl ester of ceftezole (CFZ-ET) was synthesized as a prodrug by esterification of ceftezole (CFZ) with ethoxycarbonyloxyethyl chloride and was confirmed by spectroscopic analyses. CFZ-ET was more lipophillic than CFZ as assessed by n-octanol and water partition coefficients at various pH. CFZ-ET itself did not show any microbiological activity in vitro, but showed substaintial microbiological activity after oral administration of CFZ-ET, indicating that CFZ-ET is converted to microbiologically active metabolite, probably CFZ, in the body. When CFZ-ET was incubated in blood, liver and intestine homogenates of rabbits, liver homogenate showed the fastest conversion of CFZ-ET. CFZ-ET appears rapidly metabolized in the liver when given orally due to the hydrolysis of the ester to CFZ, the parent drug of CFZ-ET. In vivo metabolism of CFZ-ET to CFZ was confirmed in rabbit by HPLC analysis. CFZ-ET were higher than those in the serum samples taken after oral administration of equivalent amount of CFZ. Oral bioavailability of CFZ-ET was 1.5-fold higher than that of CFZ in rabbits because of enhanced lipophilicity and absorption. Based on these findings, CFZ-ET appears useful as a prodrug of CFZ to improve the oral bioavailability of CFZ.

• Korean Journal of Pharmacognosy
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• v.42 no.3
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• pp.223-228
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• 2011

Chaenomeles sinensis Koehne (Rosaceae) is a deciduous tree and is distributed in China, Korea and Japan. In previous studies on the fruits of C. sinensis, some triterpenoid compouds such as oleanolic acid, tormentic acid were reported. In an ongoing investigation into biologically active compounds from natural products, the methanol extract of the stems of C. sinensis was investigated. By means of the repeated column chromatography using silica gel, Sephadex LH-20, LiChroprep RP-18, betulin (1), tormentic acid (2), 1-${\beta}$-D-glucopyranosyl-3,4,5-trimethoxybenzene (3), lyoniresinol-2a-O-${\alpha}$-L-rhamnopyranoside (4) were isolated. The chemical structures of compounds 1-4 were determined by the basis of physico-chemical properties and spectroscopic methods such as 1D and 2D NMR. For the isolated compounds (1-4), the inhibitory activity of IL-6 production in TNF-${\alpha}$ stimulated MG-63 cell was examined. Among the isolates, betulin (1), 1-${\beta}$-D-glucopyranosyl-3,4,5-trimethoxybenzene (3), lyoniresinol-2a-O-${\alpha}$-L-rhamnopyranoside (4) showed inhibitory effects on IL-6 production in TNF-${\alpha}$ stimulated MG-63 cell.