• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.170-170
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• 2009

From the analysis of current density-luminance-voltage characteristics of the double layered device in ITO/N,N'-diphenyl-N-N'bis(3-methylphenyl)-1,1'biphenyl-4,4'-diamine(TPD)/tris(8-hydroxyquinoline)aluminum($Alq_3$)/Al, we divided the conductive mechanism by four region according to applied voltage. We have obtained a coefficient of ${\beta}_{ST}$ in schottky region (I) is $4.14{\times}10^{-24}$ at the electric field of $3.2{\times}10^5$ V/cm, a slope in negative resistance region (II) appears negative properties decreasing the current density J for proportional in -1.58 square at a electric field of $7.3{\times}10^5$ V/cm. A coefficient of ${\beta}_{PF}$ in Poole-Frenkel region (III) is $8.28{\times}10^{-24}$ at the electric field of $8.4{\times}10^5$ V/cm, it was confirm어 that ${\beta}_{PF}$ is agrees with a value that relates with ${\beta}_{ST}$ such as ${\beta}_{PF}=2{\beta}_{ST}$ as the ${\beta}_{PF}$ and 2 ${\beta}_{ST}$ satisfied a theoretical prediction. And it was obtained a potential barrier of ${\Phi}_{FN}$ in Fower-Nordheim region(IV) is 0.3 eV at the electric field of $11.2{\times}10^5$ V/cm.

• Archives of Pharmacal Research
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• 제24권4호
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• pp.312-315
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• 2001

Repeated column chromatographic separation of the $CH_{2}Cl_{2}$ extract of Artemisia stolonofera (Asteraceae) led to the isolation of a triterpene (I), a sesquiterpene (II), two aromatic compounds (III and IV) and a benzoquinone (V). Their structures were determined by spectroscopic means to be simiarenol (I), (1S,7S)-1 $\beta$-hydroxygermacra-4(15),5, 10(14)-triene (II), 3'-methoxy-4'-hydroxy-trans-cinnamaldehyde (III), vanillin(IV) and 2,6-dimethoxy-1,4-benzoquinone (V), respectively. Among these products, compound V showed significant cytotoxicity against five human tumor cell lines in vitro, A549 (non small cell lung adenocarcinoma), SK-OV-3 (ovarian), SK-MEL-2 (skin melanoma), XF498 (CNS) and HCT15 (colon) with ED_{50}$ values ranging from 1.33~4.22${\mu}g/ml$.

• Bulletin of the Korean Chemical Society
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• 제14권4호
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• pp.497-499
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• 1993

Irradiation of 4-biphenylyl-4-methyl-2-cyclohexenone (5) in benzene or methanol produced trans-6-biphenylyl-5-methylbicyclo[3,1,0]hexan-2-o ne (5a) and 3-biphenylyl-4-methylcyclohex-2-enone (5b). Electronic configurations of the excited states for 5a and 5b were assigned as n, ${\pi}^*$ and ${\pi}$, ${\pi}^*$ triplet states respectively. Irradiation of 4-methyl-4(${\beta}$-naphthyl)-2-cyclohexenone in benzene or methanol gave 4-methyl-3-(${\beta}$ -naphthyl)-2-cyclohexenone (6a), which is thought to arise from ${\pi}$, ${\pi}^*$ triplet state.

• The Korean Journal of Physiology and Pharmacology
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• 제14권3호
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• pp.185-189
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• 2010

The present study demonstrates the effect of fibrates, agonists of $PPAR{\alpha}$ on cytokines-induced proliferation in primary cultured astrocytes. Alone or combination treatment with cytokines, such as IL-$1{\beta}$ (10 ng/ml), $IFNP{\gamma}$ (10 ng/ml), and TNF-$\alpha$ (10 ng/ml) cause a significant increase of cell proliferation in a time-dependent manner. Treatment of astrocytes with bezafibrate and fenofibrate (0, 5, and $10\;{\mu}M$) reduced the $IFNP{\gamma}$ and IL-$1{\beta}$-induced cell proliferation in a dose-dependent manner. To address the involvement of IL-6 on the $IFNP{\gamma}$ and IL-$1{\beta}$-induced cell proliferation, released IL-6 level was measured. $IFNP{\gamma}$ and IL-$1{\beta}$ cause an increase of released IL-6 protein level in a time-dependent manner. Furthermore, pretreatment with IL-6 antibody (0, 0.1, 1, 2.5, and 5 ng/ml) dose-dependently inhibited the $IFNP{\gamma}$ and IL-$1{\beta}$-induced cell proliferation. However, bezafibrate and fenofibrate did not affect increased mRNA and protein levels of IL-6 in $IFNP{\gamma}$ and IL-$1{\beta}$-stimulated astrocytes. Taken together, these results clearly suggest that activation of $PPAR{\alpha}$ attenuates the $IFNP{\gamma}$ and IL-$1{\beta}$-induced cell proliferation through IL-6 independent pathway.

• 한국미생물·생명공학회지
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• 제9권4호
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• pp.207-212
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• 1981

토양에서 분리된 여러가지 곰팡이류 가운데 $\beta$-galactosidase 분비력이 강하고 중성부근에서 효소안정성이 높은 Penicillium sp. 균주를 $\beta$-galactosidase 생산균주로 선정하였다. 이 균주는 밀기울고체배지에서 3$0^{\circ}C$ 72시간 배양에서 galactosidase 분비력이 가장 높았으며 질소원 첨가배지에서 질소원의 종류에 따라 14%~85%까지 증가되었다. 고체배지에서 얻은 효소추출액을 ammonium sulfate fractionation, SP-Sephadex C-50 chromatography, ultrogel AcA44 filtration, hrdroxrapatite chromatography등에 의하여 비활성도는 101 units/mg protein으로 5050배 정제되었다. 최종적으로 정제된 galactosidase는 analytical ultracentrifuge에서 단일단백으로 Schlieren pattern을 나타냈고 Disc electrophoresis에서는 단일 band로서 전기영동되었으며 영동된 $\beta$-galactosidase 활성 band와 일치하였다.

• 천문학논총
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• 제32권3호
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• pp.421-438
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• 2017

Through the short-period variability survey program, we obtained time-series BV CCD images for $1.5^{\circ}{\times}1.0^{\circ}$ region around the young open cluster NGC 457. As a result, we have detected 61 variable stars including 31 new ones after checking light curves of all stars by eyes. The 61 variable stars were included 14 ${\delta}$ Scuti variable stars, a ${\beta}$ Cephei variable star, 10 variable Be and slowly pulsating B stars, 13 eclipsing binary stars, 21 semi-long periodic or slow irregular variables and an RR Lyrae variable star, respectively. Many variable B-type stars were known through a well-defined zero-age main sequence to the ${\beta}$ Cepheid region of NGC 457. Most of the variable B-type stars found this paper were known variable stars. But, 11 out of 14 ${\delta}$ Scuti variable stars were newly discovered. The new variable stars except for ${\delta}$ Scuti stars were 4 variable B-type stars, 5 eclipsing binaries and 11 semi-long periodic or slow irregular variables. We have performed frequency analysis for all ${\delta}$ Scuti stars, a ${\beta}$ Cepheid star and an RR Lyrae star.

• 약학회지
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• 제41권6호
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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.

• 한국콘텐츠학회논문지
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• 제17권5호
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• pp.491-498
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• 2017

본 연구는 화이트 노이즈와 핑크노이즈가 뇌에 미치는 영향을 증명하기 위해 확률 공명(stochastic resonance, SR) 현상으로 확인하고자 한다. 피실험자 20명(여 10, 평균나이 $23.3{\pm}2.14$)을 대상으로 각각 노이즈 청각 자극을 제시하고 뇌파를 측정했으며, 주파수 분석을 통해 뇌 활성도를 확인했다. 분석결과, 레퍼런스, 화이트 노이즈 보다 핑크 노이즈 자극 시 alpha, low beta 대역이 증가하고, high beta 대역이 감소했다. 또한 전두엽과 측두엽 지점에서 유의하게 증가했으며, 뇌 활성도가 우반구에서 유의하게 우세한 패턴을 확인했다. 이 결과는 노이즈의 새로운 긍정적인 활용성 모색과 청각영역에 관한 뇌신경과학분야의 기초 연구로써 활용 가능할 것으로 사료된다.

• Bulletin of the Korean Chemical Society
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• 제14권4호
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• pp.491-496
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• 1993

A class A ${\beta}$-lactamase from Staphylococcus aureus PC1 complexed with 3R,5R-clavulanate is studied. The starting geometry for the computation is the crystal structure of the ${\beta}$-lactamase. Docking of the clavulanate to the enzyme is done exploiting the requirements of electrostatic and shape complementarity between the enzyme and clavulanate. This structure is then hydrated by water molecules and refined by energy minimization and short molecular dynamics simulation. In the energy refined structure of this complex, the carboxyl group of the clavulanate is hydrogen bonded to Lys-234, and the the carbonyl carbon atom of the clavulanate is adjacent to the $O_{\gamma}$ of Ser-70. It is found that a crystallographic water molecule initially located at the oxyanion hole, which is formed by the two -NH group of Ser-70 and Gln-237, is replaced by the carbonyl oxygen atom of the 3R,5R-clavulanate after docking and energy reginement. The crystallographic water molecules are proved to be important in ligand binding. Glu-166 residue is found to be repulsive to the binding of clavulanate, which is in agreement with experimental observation. Arg-244 residue is found to be important to the binding of clavulanate as well as to interaction with C2 side chain of the clavulanate. The electron density redistribution of the clavulanate on binding to the ${\beta}$-lactamase in studied by an ab initio quantum-mechanical calculation. A significant redistribution of electron density of the clavulanate is induced by the enzyme, toward the enzyme, toward the transition state of the enzymatic reaction.

• Journal of Magnetics
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• 제9권4호
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• pp.105-108
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• 2004

The attempt for the addition of double-phase nanocomposite $Nd_2Fe_{14}BFe_3B$ powders, respectively, into several $RE_2Fe_{14}B$(RE=Pr, Nd) powders with high magnetic properties was carried out. The powders were compounded and compressed to take shape bonded magnets. By means of investigating the variation of compound magnet $B_r$, the interaction between magnetic powders was revealed. The result shows that not chemical just but physical interaction exists between elements. The compound effect of $Nd_2Fe_{14}BFe_3B$-ferrite bonded magnets was detailed studied. The functional relation was revealed between magnetic properties and ferrite content. That is $Y = 5.42 x^2 -11.34x + 6.62$. The variation of $_iH_c$ temperature coefficient ${\beta}_{iHc}$ with ferrite content was investigated. Following the ferrite content increased, ${\beta}_{iHc}$ and $h_{irr}$ were obviously decreased, compression-resistant strength was enhanced.