• Korean Journal of Pharmacognosy
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• v.26 no.2
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• pp.122-129
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• 1995

The study on phytochemical analysis and the biological activity of Kalopanacis Cortex was carried out in this research. As a phytochemical result, liriodendrin as a lignan glycoside was isolated and characterized. Two subfraction separated from the acidic substance of $CHCl_3$ fraction were saturated and unsaturated fatty acid, respectively. Saturated fatty acid mixture identified from GC-MS tool was as follows: palmitic acid, stearic acid, arachidic acid, heneicosanoic acid, docosanoic acid, tricosanoic acid, tetracosanoic acid, pentacosanoic acid, hexacosanoic acid and octacosanoic acid. Unsaturated fatty acid was found to be linoleic acid on the basis of spectroscopic method. An active principle of liriodendrin exhibited significant antihepatotoxic activity but failed to show a considerable antiedemic activity. In this paper, the result of writhing test on liriodendrin was also described.

• Journal of Pharmaceutical Investigation
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• v.25 no.4
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• pp.323-330
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• 1995

Ceftezole pivaloyloxymethyl ester(CFZ-PV) was synthesized to improve oral absorption and bioavailability of parent drug by esterification of ceftezole(CFZ) with chloromethyl pivalate. The successful synthesis of CFZ-PV was conformed by spectroscopic analysis. Partition coefficient studies showed that CFZ-PV is more lipophillic than CFZ. The pharmacokinetic characteristics of CFZ-PV and CFZ were compared following oral administrations of these compounds to rabbits. The amount of CFZ in plasma was determined with an HPLC method. The ester compound (prodrug) was not detected in plasma following oral administration of CFZ-PV, and although CFZ-PV had not microbiological activity in vitro, the plasma taken after oral administration of CFZ-PV had microbiological activity. From above observations, it was noted that CFZ-PV is rapidly hydrolyzed to CFZ in the body. And the oral absorption of CFZ-PV was increased by yielding 2-fold bioavailability rather than CFZ. Therefore, CFZ-PV could be a novel prodrug of CFZ which can improve the oral bioavailability of CFZ.

• Bulletin of the Korean Chemical Society
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• v.32 no.10
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• pp.3660-3665
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• 2011

CO-tolerant PtMo/C alloy electrocatalyst was prepared by a colloidal method, and its electrocatalytic activity toward CO oxidation was investigated. Electrochemical study revealed that the alloy catalyst significantly enhanced catalytic activity toward the electro-oxidation of CO compared to Pt/C counterpart. Cyclic voltammetry suggested that Mo plays an important role in promoting CO electro-oxidation by facilitating the formation of active oxygen species. The effect of Mo on the electronic structure of Pt was investigated using X-ray absorption spectroscopy to elucidate the synergetic effect of alloying. Our in-depth spectroscopic analysis revealed that CO is less strongly adsorbed on PtMo/C catalyst than on Pt/C catalyst due to the modulation of the electronic structure of Pt d-band. Our investigation shows that the enhanced CO electrooxidation in PtMo alloy electrocatalyst is originated from two factors; one comes from the facile formation of active oxygen species, and the other from the weak interaction between Pt and CO.

• Korean Journal of Plant Resources
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• v.27 no.6
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• pp.635-641
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• 2014

Scutellaria baicalensis $G_{EORGI}$ (Scutellariae Radix) has been used to clear heat and to dry dampness in the stomach or intestines, which manifests as diarrhea or dysenteric disorder. In this study, we investigated the effective preparation of active components in Scutellariae Radix using the methods of solvent extraction and absorption fractionation for the development of new functional food or pharmaceuticals. The marker substances, baicalin, baicalein, wogonoside, and wogonin were directly isolated from the Scutellariae Radix. There chemical structures were elucidated by spectroscopic analysis. The Scutellariae Radix was extracted with hot water. To enhance yield of flavonoids in Scutellariae Radix, the hot water extract was dissolved in ethanol with concentration dependent manner. The precipitates were separated using centrifugal techniques at 10,000 rpm. Supernatant liquid was applied to the HPLC for quantification of major compounds. Separately, the hot water extract was absorbed on Diaion HP-20 resin. And then, the absorbed fraction was eluted with methanol for HPLC. The contents of baicalin, baicalein, wogonoside and wogonin in different treatment methods were analyzed by HPLC. Total amount of four major components were 16.9% in 50% ethanol extract, 21.7% in 70% ethanol extract, 20.5% in 90% ethanol extract, and 39.3% in absorbed fraction of Diaion HP-20 resin. In these results, we found that resin absorption method is suitable for the extraction of enriched flavonoids from Scutellariae Radix.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.10a
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• pp.279-282
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• 2010

스티로폼샌드위치패널은 건식공법의 시공편리성, 경제적인 공사비용, 뛰어난 단열성능으로 공장이나 창고건축물을 중심으로 많이 사용되고 있다. 그러나 스티로폼의 여러 가지 장점에도 불구하고 화재에 취약한 단점이 있어 최근 난연성능이 보완된 난연스티로폼패널의 사용이 증가하고 있다. 최근 건축현장에서, 가짜 난연스티로폼패널 사용이 문제되고 있으나 난연성능의 현장 확인에 어려움이 있고 콘칼로리미터 등의 난연성능평가에 시간과 비용이 소요된다. 본 연구에서는 콘칼로리미터를 통해 난연성능이 확보된 난연 스티로폼패널의 심재와 일반스티로폼패널 심재를 대상으로 근-적외선 분광분석을 수행하여 난연성능의 유무에 따라 상이하게 나타나는 고유스펙트럼 흡수를 측정하였다. 각 제품마다 측정된 고유스펙트럼은 통계처리를 통하여 난연스티로폼의 진위여부를 현장에서 구별할 수 있음을 확인하였으며, 비용효율이 높은 현장평가방법으로의 적용이 가능함을 실험을 통해 입증하였다.

• Bulletin of the Korean Chemical Society
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• v.21 no.7
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• pp.679-684
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• 2000

The Sr2Co0.5Nb(Ta)0.5O4 and Sr3CoNb(Ta)O7 compounds, both with Ruddlesden-Popper structures, have been synthesized by the ceramic method at $1150^{\circ}C$ under atmospheric pressure. The crystallographic structure of the compounds was assigned to the tetr agonal system with space group 14/mmm by X-ray diffraction(XRD) Rietveld refinement. The reduced lattice volume and lattice parameters increased as the Ta with 5d substitutes for the Nb with 4d in the compounds. The Co/Nb(Ta)O bond length has been determined by X-ray absorption spectroscopic(EXAFS/XANES) analysis and the XRD refinement. The CoO6,octahedra were tetragonally distorted by elongation of Co-O bond along the c-axis. The magnetic measurement shows the compounds Sr2Co0.5Nb(Ta)0.5O4 and Sr3CoNb(Ta)O7 have paramagnetic properties and the Co ions with intermediate spin sates between high and low spins in D4h symmetry. All the compounds showed semiconducting behavior whose electrical conductivity increased with temperature up to 1000 K. The electrical conductiviy increased and the activation energy for the conduction decreased as the number of perovskite layers increased in the compounds with chemical formula An+1BnO3n+1.

• Journal of The Korean Astronomical Society
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• v.55 no.4
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• pp.131-138
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• 2022

We report the discovery of four quasars with M₁₄₅₀ ≳ -25.0 mag at z ~ 5 and supermassive black hole mass measurement for one of the quasars. They were selected as promising high-redshift quasar candidates via deep learning and Bayesian information criterion, which are expected to be effective in discriminating quasars from the late-type stars and high-redshift galaxies. The candidates were observed by the Double Spectrograph on the Palomar 200-inch Hale Telescope. They show clear Lyα breaks at about 7000-8000 Å, indicating they are quasars at 4.7 < z < 5.6. For HSC J233107-001014, we measure the mass of its supermassive black hole (SMBH) using its C _IV λ1549 emission line. The SMBH mass and Eddington ratio of the quasar are found to be ~10⁸ M_⊙ and ~0.6, respectively. This suggests that this quasar possibly harbors a fast growing SMBH near the Eddington limit despite its faintness (L_Bol < 10⁴⁶ erg s^-1). Our 100% quasar identification rate supports high efficiency of our deep learning and Bayesian information criterion selection method, which can be applied to future surveys to increase high-redshift quasar sample.

• Korean Journal of Medicinal Crop Science
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• v.10 no.3
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• pp.200-205
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• 2002

Platycodin D was isolated from n-butanol extract of Platycodi radix(Platycodon grandiflorum and identified by the spectroscopic analysis using $^1H$ and $^{13}C$ NMR techniques. A new method of analysis of platycodin D by high performance liquid chromatography(HPLC) was established using a reversed phase system with YMC-Pack ODS-AM( 250 X 4.6 mm) column and 30% acetonitrile as a mobile phase. Evaporative light scattering detector was used as detector. The kinds of extraction solvents and methods were examined to determine the efficient extraction condition and HPLC analysis was carried out to establish the optimum drying condition for the root of Platycodon grandiflorum. The contents of Platycodin D was highest as 0.083% when platycodon roots were dried at $60^{\circ}C$ using dry oven.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.335-335
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• 2008

Phosphate glass samples with various $Cr_2O_3$ and $Er_2O_3$ contents based upon $55P_2O_5\cdot24BaO\cdot10K_2O\cdot4Al_2O_3\cdot6Yb_2O_3$ were prepared. The prepared glass compositions are dehydrated using gas bubble flow method in open system and investigated the effects of the eliminating of OH groups from the glass melts with bubbling time. It was found that the probability of $Er^{+3}$ fluorescence quenching by OH groups oscillations linear depends upon the OH groups absorption coefficients in the maximum of the stretch vibrations band at $3500cm^{-1}$ while $Er^{+3}$ concentration range is between $1.6\times10^{19}$ and $21.2\times10^{19}$ ion/$cm^3$.

• Fisheries and Aquatic Sciences
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• v.23 no.3
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• pp.9.1-9.6
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• 2020

Background: Fucosterol is a compound commonly found in algae that has various biological activities. The purpose of this study was to develop a high-performance liquid chromatography (HPLC) validation method for fucosterol and to compare the fucosterol contents of 11 algal species from Ulleungdo, Korea. Method: In this study, we successfully isolated and identified fucosterol from a 70% EtOH extract of Sargassum miyabei, and subsequently conducted specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, and precision analyses for development of an HPLC validation method. Fucosterol contents were compared using the established HPLC validation conditions. Results: We successfully isolated fucosterol from a 70% EtOH extract of S. miyabei and identified it based on spectroscopic analysis. On the basis of HPLC validation using the fucosterol isolated from S. miyabei, we confirmed specificity (8.5 min), linearity (R² = 0.9998), LOD (3.20 ㎍ mL^-1), LOQ (9.77 ㎍ mL^-1), accuracy (intra-day and inter-day variation, 90-110%), and precision (RSD, 1.07%). Fucosterol contents in the 11 assessed algal species ranged from 0.22 to 81.67 mg g^-1, with the highest content being recorded in a 70% EtOH extract of Desmarestia tabacoides (81.67 mg g^-1), followed by that of Agarum clathratum (78.70 mg g^-1). Conclusions: The results indicate that 70% EtOH extracts of D. tabacoides and A. clathratum containing fucosterol with various effects can be potential alternative sources of fucosterol.