• Natural Product Sciences
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• v.14 no.4
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• pp.281-288
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• 2008

From the MeOH extract of the whole plants of Lathyrus davidii (Fabaceae), thirteen constituents were isolated and identified as the flavonoids astragalin, isoquercitrin, nicotiflorin, and rutin, as the saponins soyasapogenol B 3-O-${\beta}$-D-glucuronopyranoside, azukisaponins II and V, soyasaponins II and V and as 4-O-${\beta}$-Dglucopyranosyl syringic acid, uracil and n-hexacosanol. Five saponins and 4-O-${\beta}$-D-glucopyranosyl syringic acid were isolated from the BuOH fraction as their methyl esters. Ombuoside (rutin 7,4'-di-O-methyl ether) was also isolated from the methylated BuOH-soluble fraction. However, no ombuoside was detected in the HPLC analysis of the nonmethylated BuOH fraction. Therefore, ombuoside is an artifact derived from methylation of rutin. All of these compounds were isolated for the first time from this plant.

• Biomolecules & Therapeutics
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• v.11 no.4
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• pp.245-248
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• 2003

The purpose of this study was to evaluate tyrosinase inhibitory activity of plant extracts, especially Korean indigenous plants, for the cosmetic use of skin whitening. When 50 plant extracts were tested, the methanol extracts of Agrimonia pilosa, Aster scaber; Dianthus sinensis, Fatsia japonica, Hemistepta lyrata, Lespedeza cuneata, Osmunda japonicum, Pyrvla japvnica, Rodgersia phodophylla and Veratrum grandiforum possessed the considerable tyrosinase inhibitory activity at 3-300 $\mu\textrm{g}$/mL. Especially, L. cuneata, aerial part of O. japonicum and V. gandiforum exhibited the strong inhibition (>50％ inhibition at 300 $\mu\textrm{g}$/mL). In particular, the methanol extract of V. grandiforum and its ethylacetate fraction showed potent inhibition ($IC_{50}$/=30 and 13$\mu\textrm{g}$/mL, respectively), while the reference compound, kojic acid, showed $IC_{50}$/ value of 26$\mu\textrm{g}$/mL. These plant extracts may be used as tyrosinase inhibitors in cosmetics.

• Journal of Korean Neurosurgical Society
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• v.29 no.3
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• pp.402-406
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• 2000

The term 'craniovertebral junction' refers to the occipital bone that surrounds the foramen magnum and the atlas and the axis vertebrae. A wide variety of congenital, developmental, and acquired anomalies exist at the craniovertebral junction. The authors present a rare case of the congenital anomaly of the craniovertebral junction consisting of atlantal hypoplasia, atlantal assimilation, and basilar invagination in a 58-year-old male. An occiput-C2 arthrodesis was performed. The clinical and imaging features are described, and the embryology and etiology of this anomaly are discussed.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.321.2-321.2
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• 2002

Possible role of anti-inflammatory effects of a new iridoids, patridoid I. II and II-A which were isolated from Patrinia saniculaefolia. examined by assessing their effects on tumor necrosis factor $\alpha$ (TN F$\alpha$) and 2 enzymes, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in the lipopolysaccaride (LPS)-stimulated murine macrophage-like cell line RAW 264.7. Among them. patridoid II consistently inhibited the production of TNF$\alpha$ and NO production in a dose dependent manner. But patridoid I and patrioid ll isomer palrioid ll-A. these compounds very weakly inhibited NO producion. Moreover. treatment of macrophage with these compounds, the decrease in NO products was accompanied by a decrease in iNOS protein level as assessed by Western Blot. But these compounds did not affect COX-2 protein expression in LPS-stimulated macrophage. Our results suggest that patridoid ll could become a leading compound for developing a novel of anti-inflammalory drugs.

• Biomolecules & Therapeutics
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• v.14 no.3
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• pp.166-170
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• 2006

In this study, we investigated whether schizandrin, schizandrin-A, gomisin-A and uridine affect mucin secretion from cultured airway epithelial cells and compared the potential activities of these agents with the inhibitory action on mucin secretion by poly-1-lysine (PLL) and the stimulatory action by adenosine triphosphate (ATP). Confluent primary hamster tracheal surface epithelial (HTSE) cells were metabolically radiolabeled using $^3H-glucosamine$ for 24 h and chased for 30 min in the presence of varying concentrations of each agent to assess the effects on $^3H-mucin$ secretion. The results were as follows: schizandrin-A and uridine increased mucin secretion at the highest concentrations ($2{\times}10^{-4}\;-\;10^{-3}M$). We conclude that schizandrin-A and uridine can stimulate mucin secretion via direct effect on airway mucin-secreting cells and suggest that these agents be further investigated for the potential use as mucoregulators during the treatment of chronic airway diseases.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.426-426
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• 2012

본 연구에서는 GaAs p-i-n 접합 구조에 InAs 양자점을 삽입한 양자점 태양전지(Quantum Dot Solar Cell; QDSC)의 내부 전기장(internal electric field)을 조사하기 위하여 Photoreflectance (PR) 방법을 이용하였다. QDSC 구조는 GaAs p-i-n 구조의 공핍층 내에 8주기의 InAs 양자점 층을 삽입하였으며 각 양자점 층은 40 nm 두께의 i-GaAs로 분리하였다. InAs/GaAs QDSC는 분자선박막 성장장치(molecular beam epitaxy; MBE)를 이용하여 성장하였다. 이 때 양자점의 형성은 InAs 2.0 ML(monolayer)를 기판온도 $470^{\circ}C$에서 증착하였다. QDSC 구조에서 여기광원의 세기에 따른 전기장의 변화를 조사하였다. 아울러 양자점 층 사이의 i-GaAs 층 내에 6.0 nm의 AlGaAs 퍼텐셜 장벽(potential barrier)을 삽입하여 퍼텐셜 장벽 유무에 따른 전기장 변화를 조사하였다. PR 측정에서 여기광원으로는 633 nm의 He-Ne 레이저를 이용하였으며 여기광의 세기는 $2mW/cm^2$에서 $90mW/cm^2$까지 변화를 주어 여기광세기 의존성실험을 수행하였다. 여기광의 세기가 증가할수록 photovoltaic effect에 의한 내부 전기장의 변화를 관측할 수 있었다. PR 결과로부터 p-i-n 구조의 p-i 영역과 i-n 접합 계면의 junction field를 검출하였다. p-i-n의 i-영역에 양자점을 삽입한 경우 PR 신호에서 Franz-Keldysh oscillation (FKO)의 주파수가 p-i-n 구조와 비교하여 변조됨을 관측하였다. 이러한 FKO 주파수성분은 fast Fourier transform (FFT)을 이용하여 검출하였다. FKO의 주파수 성분들은 고전기장하에서 electron-heavyhole (e-hh)과 electron-lighthole (e-lh) 전이에 의해 나타나는 성분으로 확인되었다.

• The Korean Journal of Physiology and Pharmacology
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• v.10 no.5
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• pp.251-254
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• 2006

Schizandrae Fructus has been used for controlling respiratory allergic or inflammatory diseases in folk medicine and their components, schizandrin, schizandrin-A and gomisin-A were reported to have diverse biological effects. In this study, we investigated whether schizandrin, schizandrin-A and gomisin-A affect adenosine triphosphate (ATP)-induced mucin secretion from cultured airway epithelial cells. Confluent primary hamster tracheal surface epithelial (HTSE) cells were metabolically radio labeled using $^{3}H-glucosamine$ for 24 h and chased for 30 min in the presence of varying concentrations of each agent to assess the effects on $^{3}H-mucin$ secretion. The results were as follows: 1) schizandrin significantly inhibited ATP-induced mucin secretion; 2) However, schizandrin-A and gomisin-A did not affect ATP-induced mucin secretion, significantly. We conclude that schizandrin can inhibit ATP-induced mucin secretion by directly acting on airway mucin-secreting cells. Therefore, schizandrin should further be investigated for the possible use as mucoregulators in the treatment of inflammatory airway diseases.

• Journal of the Korean Ceramic Society
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• v.53 no.3
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• pp.282-287
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• 2016

This study involves enhancing the performance of the $Na(Li,Ti)O_2$ system as an Na-ion battery anode with the addition of Mg, which partially replaces Li ions. We perform both computational and experimental approaches to achieve a higher reversible capacity and a faster transport of Na ions for the devised system. Computational results indicate that the $Na(Li,Mg,Ti)O_2$ system can provide a lower-barrier path for Na-ion diffusion than can a system without the addition of Mg. Experimentally, we synthesize various $Na_z(Li_y,Mg_x,Ti)O_2$ systems and evaluate their electrochemical characteristics. In agreement with the theoretical study, Mg addition to such systems improves general cell performance. For example, the prepared $Na_{0.646}(Li_{0.207}Mg_{0.013}Ti_{0.78})O_2$ system displays an increase in reversible capacity of 8.5% and in rate performance of 13.5%, compared to those characteristics of a system without the addition of Mg. Computational results indicate that these improvements can be attributed to the slight widening of the Na-$O_6$ layer in the presence of Mg in the $(Li,Ti)O_6$ layer.

• International Journal of Industrial Entomology and Biomaterials
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• v.8 no.1
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• pp.51-59
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• 2004

Phylogenetic relationships were analyzed among bumblebees using a portion of mitochondrial (mt) 16S ribosomal RNA (16S rRNA). Eight species of true bumblebees and one species of cuckoo bumblebee (Bombini, Apidae), collected from Korea were included in the analysis. Also, one species of true bumblebee imported from several foreign countries for pollination was included. The length of mt 16S rRNA sequence ranged from 496 bp to 508 bp and sequence divergence ranged from 1.4％ (7 bp) to 15.49％ (77bp). As expected, a high A＋T content was observed (78.5％ on average). According to the phylogeny tree derived from parsimony and maximum likelihood analysis, a monphyletic Bombus species, excluding a single cuckoo bumblebee, Psithyrus coreanus, was obtained, but the bootstrap estimate at the node supporting the monophyletic group was very weak (40％ or 46％), suggesting a very close relationship of the cuckoo bumblebee to the true bumblebee. Within Bombus species belonging to identical subgenera subgeneric specific clustering was formed with high bootstrap values, implying validity of the subgeneric names of each species: Pyrobombus for B. ardens and B. modeatus; Megabombus for B. consobrinus wittenburgi and B. koreanus; and Bombus s. str. for B. ignitus, B. hypocrita sapporoensis, and B. terrestris.

• Korean Journal of Pharmacognosy
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• v.37 no.4 s.147
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• pp.294-301
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• 2006

The aim of this study was to investigate the protective activity of gomisin A and gomisin N, bioactive lignan components isolated from Schizandae Fructus, on hepatocyte injury induced by carbon tetrachloride($CCl_4$, 10 mM), t-butyl hydroperoxide(TBH, 0.5 mM), and D-galactosamine(GalN, 30 mM). Primary cultures of rat hepatocyte(18 h culture) were treated with $CCl_4$, TBH or GalN and various concentrations(0.1, 1, 10, $100{\mu}M$) of gomisin A or gomisin N. $CCl_4$ significantly increased the levels of lactate dehydrogenase(LDH), alanine aminotransferase(ALT), and aspartate aminotransferase(AST). These increases were inhibited by gomisin N. TBH significantly increased the level of AST; an increase that was inhibited by gomisin N. GalN markedly increased the levels of LDH and ALT, and these increases was significantly inhibited by both gomisin A and gomisin N. These results suggest that gomisin A and gomisin N have the hepatoprotective activity.