• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1997년도 춘계학술대회
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• pp.109-109
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• 1997

Inhibitory effect on DNA topoisomerase-I, rate of glutathione conjugation and cytotoxicity of naphthoquinone derivatives were correlated. During 5 min exposure of the derivatives to glutathione (GSH), it was found that 14% of 5,8-dimethoxy-1,4-naphthoquinone(DMNQ) was converted into a GSH-conjugate, whereas 5,8-dihydroxy-1,4-naphthoquinone(DHNQ) did not interact with GSH, implying that DMNQ exerted higher electrophilicity than DHNQ. However, DHNQ (IC$\_$50/, 0.15 ${\mu}$M) showed stronger cytotoxicity in L1210 cells than DMNQ(IC$\_$50/, 0.45 ${\mu}$M). The stronger cytotoxicity of DHNQ, compared to DMNQ, could be ascribed to more rapid redox cycling. Both naphthoquinones (IC$\_$50/, 60-65 ${\mu}$M) exhibiting about the same inhibitory effect on DNA topoisomerase-I were more potent than 1,4-naphthoquinone(1,4-NQ, IC$\_$50/, 134 ${\mu}$M). Thus, 5,8-oxy groups in the structure seem to be important for the inhibition of the enzyme. DMNQ showed a broader dose range while maintaining a good antitumor activity against S-180 fluid tumor. For these reasons, DMNQ was taken as useful pharmacophore for structural modification. Introduction of 1-hydroxyalkyl groups at C-2 of DMNQ lowered all of the activities mentioned above, while acetylation of 1-hydroxyalkyl moiety enhanced the activities by 4-5 times. Introduction of the same side chains at C-6 exhibited stronger activities than 2-substituted ones. Based on these results it was suggested that the quinonoid moiety in 6-substituted DMNQ was more exposed to cellular nucleophiles such as DNA, thiols of enzymes and so on. The synthesis of DHNQ or DMNQ derivatives are going on, and the corelationship between structure-activity will be discussed.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2009년도 한국우주과학회보 제18권2호
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• pp.35.3-36
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• 2009

To investigate properties of the stellar contents of the resolved asymptotic giant branch stars in the nearby dwarf galaxies, we obtained wide-field JHKs images of the dwarf irregular galaxies NGC 6822, IC 1613 and the dwarf elliptical galaxy NGC 205, using the WIRCam near-infrared imager of the CFHT. The obtained (J-Ks, Ks) and (H-Ks, Ks) color-magnitude diagrams for the resolved stars in the galaxies contain populations of foreground stars, super giant stars, red giant stars and the asymptotic giant branch (AGB) stars. Using corollary photometric data in the visible bands, AGB stars were selected in the color-magnitude diagrams with a wide wavelength baseline in color indices. In color-color diagrams of the resolved AGB stars, we identified C stars from M giant stars for each galaxies, i.e., 726 C stars in NGC 6822, 126 C stars in IC 1613 and 593 C stars in NGC 205. The number ratios of C stars to M-giants were estimated to be $0.59\pm0.03$ in NGC 6822, $0.30\pm0.03$ in IC 1613 and $0.14\pm0.01$ in NGC 205. From analyses of the correlations of the spatial distribution of the C/M ratios with the HI properties and dynamical structures of the target galaxies, we discuss environmental effects of the star formation in the galaxies. We also discuss the epochs of the AGB star formation in the galaxies by comparing theoretical isochrones with the color distributions and luminosity functions of the AGB stars.

• Archives of Pharmacal Research
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• 제29권11호
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• pp.969-976
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• 2006

Novel chalcones were found as potent inhibitors of interleukin-5 (II-5). 1-(6-Benzyloxy-2-hydroxyphenyl)-3-(4-hydroxyphenyl)propenone (2a, 78.8% inhibition at $50\;{\mu}M,\;IC_{50}=25.3\;{\mu}M$) was initially identified as a potent inhibitor of IL-5. This activity is comparable to that of budesonide or sophoricoside (1a). The benzyloxy group appears to be critical for the enhancement of the IL-5 inhibitory activity. To identify the role of this hydrophobic moiety, cyclohexyloxy (2d), cyclohexylmethoxy (2c), cyclohexylethoxy (2e), cyclohexylpropoxy (2f), 2-methylpropoxy (2g), 3-methylbutoxy (2h), 4-methylpentoxy (2i), and 2-ethylbutoxy (2j) analogs were prepared and tested for their effects on IL-5 bioactivity. Compounds 2c ($IC_{50}=12.6\;{\mu}M$), 2d ($IC_{50}=12.2\;{\mu}M$), and 2i ($IC_{50}=12.3\;{\mu}M$) exhibited the most potent activity. Considering the cLog P values of 2, the alkoxy group contributes to the cell permeability of 2 for the enhancement of activity, rather than playing a role in ligand motif binding to the receptor. The optimum alkoxy group in ring A of 2 should be one that provides the cLog P of 2 in the range of 4.22 to 4.67.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2002년도 추계학술대회 논문집
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• pp.373-378
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• 2002

Metal matrix composites have a great interest in recent years because high specific strength, high specific stiffness characteristics, and application ranges of the composites are extend to variety industry. In this paper, an investigation was performed on the plane strain fracture toughness and slinding wear properties of AC4CH alloy(Al-Si-Mg line) reinforced with 20wt% aluminum borate whisker expect one, which contained a inorganic binder($TiO_2$). the binder led to the formation of strengthen the whisker each other. The test of fracture toughness was using CT(half size) specimen of thickness 12.5mm, width 25mm. and test of slinding wear of using tribo a pin-on-disk machine and lubricant is used without paraffine 8.2CST at room temperature. As results, Fracture toughness $K_{IC}$ is $8.7MPa-m^{05}$ for ABOw/AC4CH, $9.28MPa-m^{05}$ for ABOw/AC4CH added $TiO_2$. but AC4CH alloy was violated the critical stipulated by ASTM standard for valid measurement of $K_{IC}$. In case of, it was performed $J_{IC}$ test instead of $K_{IC}$ based on ASTM E 1820.

• Parasites, Hosts and Diseases
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• 제53권1호
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• pp.21-27
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• 2015

Plants used for traditional medicine contain a wide range of substances that can be used to treat various diseases such as infectious diseases. The present study was designed to evaluate the antileishmanial effects of the essential oil and methanolic extract of Myrtus communis against Leishmania tropica on an in vitro model. Antileishmanial effects of essential oil and methanolic extract of M. communis on promastigote forms and their cytotoxic activities against J774 cells were evaluated using MTT assay for 72 hr. In addition, their leishmanicidal activity against amastigote forms was determined in a macrophage model, for 72 hr. Findings showed that the main components of essential oil were ${\alpha}$-pinene (24.7%), 1,8-cineole (19.6%), and linalool (12.6%). Findings demonstrated that M. communis, particularly its essential oil, significantly (P<0.05) inhibited the growth rate of promastigote and amastigote forms of L. tropica based on a dose-dependent response. The $IC_{50}$ values for essential oil and methanolic extract was 8.4 and $28.9{\mu}g/ml$ against promastigotes, respectively. These values were 11.6 and $40.8{\mu}g/ml$ against amastigote forms, respectively. Glucantime as control drug also revealed $IC_{50}$ values of 88.3 and $44.6{\mu}g/ml$ for promastigotes and amastigotes of L. tropica, respectively. The in vitro assay demonstrated no significant cytotoxicity in J774 cells. However, essential oil indicated a more cytotoxic effect as compared with the methanolic extract of M. communis. The findings of the present study demonstrated that M. communis might be a natural source for production of a new leishmanicidal agent.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2003년도 정기총회 및 학술대회
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• pp.69-72
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• 2003

This paper presents a signal processing IC for digital HDTV, which is designed to operate in bunt-in HDW or in HD-set-top Box. The chip supports de-multiplexing an ISO/IEC 13818-1 MPEG-2 TS stream. It decodes MPEG-2 MP@HL video bitstream, and provides high-quality scaled video for display on HDTV monitor. The chip consists of ARM7TDMI for TS-Demux, PCI interface, Audio interface, MPEG2 MP@HL video decoder Display processor, Graphic processor, Memory controller, Audio int3face, Smart Card interface and UART. It is fabricated using Sam sung's 0.18-um and the package of 492-pin BGA is used.

• Natural Product Sciences
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• 제29권1호
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• pp.50-58
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• 2023

The phytochemical investigation of the crude methanolic extracts roots and stem bark of Anthonotha cladantha (Harms) J.Léonard led to the isolation and identification of twelve secondary metabolites: 2,3-dihydroxypropyl hexacosanoate (1), hederagenine (2), cycloeucalenol (3), 2α-hydroxylupeol (4), betulinic acid (5), lupeol (6), heptacosan-2-one (7), triacontanoic acid (8), stigmast-4-en-3-one (9), β-sitosterol (10), stigmasterol (11), and stigmasterol-3-O-β-D-glucopyranoside (12). Their structures were elucidated with the help of their spectroscopic and physical data and by comparison with those reported in the literature. To the best of our knowledge, from all those compounds, 2,3-dihydroxypropyl hexacosanoate (1), hederagenine (2), cycloeucalenol (3), 2α-hydroxylupeol (4), and betulinic acid (5) are being reported for the first time from this genus. In addition, the acetylation of compound 1 afforded a new derivative 3-(hexacosanoyloxy)propane-1,2-diyl diacetate (1a). Compound 1 possessed a moderate α-glucosidase inhibitory activity with an IC₅₀ value of 39.2 ± 0.22 μM; it neither showed antioxidant activity nor inhibition against the enzyme urease. Compound 1a exhibited weak antioxidant activity in the DPPH assay with an IC₅₀ value of 80.3 ± 0.83 μM but was inactive against α-glucosidase and urease. Furthermore, both compounds 1 and 1a were inactive against seven pathogenic bacterial strains.

• 전자통신동향분석
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• 제25권5호
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• pp.33-46
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• 2010

인쇄전자회로 기술은 인쇄(graphic art printing) 공정을 활용한 다양한 광/전자 기기 개발을 위한 핵심요소 기술이다. 기능성 전자 잉크 소재와 초저가격의 프린팅 공정을 통해서 유비쿼터스 시대의 차세대 모바일 IT 기기의 생명력을 불어넣게 된다. 현재 기술 수준이 일부 요소 부품들을 제작하고 기본 단위의 정보처리를 가능케 하는 수준에 머무르고 있으나, 여러 가지 잉크 소재 및 다양한 초미세 인쇄 공정 기술의 개발이 진행됨에 따라 향후 폭넓은 분양에 적용될 것으로 기대된다. 궁극적으로 인쇄전자회로의 성능이 향상되고 고집적화 됨으로써 기존의 Si 기반 CPU나 IC 칩을 대체하는 공정으로 자리매김을 할 것으로 예상된다. 본 기고문에서는 이러한 인쇄전자회로 기술 및 동향에 대해 기술하였다. 특히, 현재 폭넓게 연구가 진행중인 차세대 디스플레이 백플레인이나 개별물품단위 트래킹을 위한 플라스틱 RFID 태그 적용을 위해 필요한 요건들을 인쇄전자회로 기술관점에서 조망하였다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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• pp.273-275
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• 2014

An ammonia fuel system is developed and applied to both a spark ignition engine and a compression ignition engine to use ammonia as primary fuel in this study. Ammonia is injected separately into the intake manifold in liquid phase while gasoline or diesel is also injected as secondary fuel. As ammonia burns 1/6 time slower than gasoline or diesel, the spark or diesel injection timing is needed to be advanced to have better combustion phasing. The test engine showed quite high variation in the power output with large amount of ammonia. The final goal of the study is to implement a methodology to ignite ammonia-air mixture and have complete combustion without any use of the conventional fuels.

• Elastomers and Composites
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• 제32권3호
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• pp.166-172
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• 1997

The objective in this study was investigated temperature susceptibility and low temperature fracture of rubber modified asphalt. A chlorinated polyethylene elastomer, Tyrin CM0730, was added to 200/300 grade asphalt with 3.0 and 5.0wt% to improve campatibility. The elastomer modified asphalts were analyzed for temperature susceptibility relating to penetration index(PI) and penetration-viscosity number(PVN) as well as low temperature fracture relating to fracture energy $(G_{IC})$. These indices were obtained from the measurements of penetration, viscosity, failure load and modulus. The addition of small amounts of elastomer to the asphalt resulted in a significant increase of both the PI and PVN over an unmodified asphalt. Also, the fracture energy increased with the addition of elastomer to asphalt. These significant improvement at both the high and low temperature result in enhanced performance.