• Bulletin of the Korean Chemical Society
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• 제35권5호
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• pp.1294-1298
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• 2014

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer representing 85% of lung cancer patients. Despite several EGFR-targeted drugs have been developed in the treatment of NSCLC, the clinical efficacy of these EGFR-targeted therapies is being challenged by the occurrence of drug resistance. In this regard, Hsp90 represents great promise as a therapeutic target of cancerous diseases due to its role in modulating and stabilizing numerous oncogenic proteins. Accordingly, inhibition of single Hsp90 protein simultaneously disables multiple signaling networks so as to overcome drug resistance in cancer. In this study, we synthesized a series of 11 butein analogues and evaluated their biological activities against gefitinibresistant NSCLC cells (H1975). Our study indicated that analogue 1h inhibited the proliferation of H1975 cells, down-regulated the expression of Hsp90 client proteins, including EGFR, Met, Her2, Akt and Cdk4, and upregulated the expression of Hsp70. The result suggested that compound 1h disrupted Hsp90 chaperoning function and could serve a potential lead compound to overcome the drug resistance in cancer chemotherapy.

• 디지털융복합연구
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• 제10권6호
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• pp.181-187
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• 2012

본 연구에서는 부동산투자와 관련한 대표적 조세인 취득세, 종합부동산세, 양도소득세에 대한 투자자의 조세 부담정도가 부동산의 투자행동(장기투자 목적 정도)에 어떠한 영향을 미치는지에 대하여 분석하고, 이러한 부동산 투자행동은 부동산 투자에 대한 투자성과(실현수익률)에 얼마나 영향을 미치는가에 대하여 분석을 실시하였다. 본 연구는 부동산 투자에 있어서 투자자에게 조세의 부담정도에 따른 투자행동의 선택결과가 최종의 투자성과에 서로 다른 결과를 나타낸다는 점을 고려하여 본 연구모델을 투자의사결정시 기초적인 의사결정 도구로 활용할 수 있을 것으로 생각된다.

• Natural Product Sciences
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• 제10권6호
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• pp.277-283
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• 2004

Psammaplin A (PSA), a naturally occurring biophenolic compound has been demonstrated to deliver significant cytotoxicity to many cancer cell lines. In this article, we investigated the effect of PSA on cell cycle progression of lung cancer cells (A549). It was found that PSA could slightly perturb the cell cycle progression of A549 cells and lead to the cell cycle arrest at G2/M phase, indicating PSA might disturb the mitosis process of A549 cells. In addition, inspired by the two phenolic groups in the structure of PSA, the antioxidant activity of it has been evaluated. Although PSA was weak in scavenging the stable free radical 1,1-diphenyl-2-picrylhyrazyl (DPPH), it showed stronger ABTS radical scavenging activity than ascorbic acid in TEAC assay. Furthermore, it was found that PSA could effectively prevent DNA strand scission induced by oxidative stress. These results suggest that PSA have both cell cycle regulation and antioxidant activities. Herein, we suggest that PSA would be a very interesting and promising candidate to be developed as a multi-function drug.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.475-480
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• 2002

The reliability of the solder joint is affected by type and extent of the interfacial reaction between solder and substrates. Therefore, understanding of intermetallic compounds produced by soldering in electronic packaging is essential. In-based alloys have been favored bonding devices that demand low soldering temperatures. For photonic and fiber optics packaging, m-based solders have become increasingly attractive as a soldering material candidate due to its ductility. In the present work, the interfacial reactions between indium solder and bare Cu Substrate are investigated. For the identification of intermetallic compounds, both Scanning Electron Microscopy(SEM) and X-Ray Diffraction(XRD) were employed. Experimental results showed that the intermetallic compounds, such as Cu$_{11}$In$_{9}$ was observed for bare Cu substrate. Additionally, the growth rate of these intermetallic compounds was increased with the reaction temperature and time. We found that the growth of the intermetallic compound follows the parabolic law, which indicates that the growth is diffusion-controlled.d.

• Tribology and Lubricants
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• 제10권4호
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• pp.43-50
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• 1994

In order to elucidate the effects of co-existing additives (S$_{8}$, TBP: Tri butyl phosphate, ZnDTP: Zinc-dialkyl dithiophosphate) and the role of reacted surface film on the friction behavior of MoDTP (molybdenum dialkyl dithiophosphate), a friction experiment using a dual circular pipe edge surface type friction tester and XPS (X-ray photoelectronic spectrum) surface analysis were conducted. Friction reduction with MoDTP lubricant was proved to be greatly influenced by co-existing additive species. It was dependent on the properties of the film formed through the reaction between the additive and the surface. Phosphate film reduced the friction coefficient of MoDTP through suppression of diffusion of Mo compounds towards the metal substrate. On the other hand, sulfate film, which is inherently rich in lattice defects, did not lead to any appreciable friction reduction with MoDTP since the diffusion of the Mo compound towards the metal substrate was not effectively suppressed. With ZnDTP additive, the sulfide film formed through decomposition greatly influenced the lubricating performance of MoDTP. As such, properties of surface films formed from additives were proved to yield significant influence on the lubrication performance of MoDTP.

• 마이크로전자및패키징학회지
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• 제8권4호
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• pp.47-52
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• 2001

Sn-Cu-Ni계 솔더를 이용한 AC Adapter의 Pb-Free Wave 솔더링 공정을 Six Sigma기법으로 개발하였다. 솔더 접합부의 외관, 미세조직, Lift-off현상 및 Crack발생 유.무를 관찰하여 접합기구를 규명하고자 하였으며 열 충격시험을 통하여 신뢰성평가를 수행하였다. 솔더 접합부의 Sn-Cu-Ni계 솔더와 Cu Land 사이에는 약 5 $\mu\textrm{m}$ 두께의 $(Cu,Ni)_6/Sn_5$ 형태의 금속간화합물이 발견되었고 열 충격후 750사이클까지는 Crack이 발견되지 않았다. 본 연구로 개발된 제품은 기존의 Sn-Pb솔더를 사용한 제품에 비해서 양산성 및 신뢰성 측면에서 우수한 특성을 나타내었다.

• Journal of Microbiology and Biotechnology
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• 제14권4호
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• pp.805-809
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• 2004

The antimite activities of cumin seed oil-derived cuminaldehyde and eleven commercial components of Cuminum cyminum oil were examined against Dermatophagoides farinae and Dermatophagoides pteronyssinus adults and compared with those of benzyl benzoate and N,N-diethyl-m-toluamide. Responses varied according to dose and mite species. On the basis of $LD_{50}$ values, the compound most toxic to D. farinae adults was cuminaldehyde ($2.40\mug/cm^2$) followed by benzyl benzoate ($9.32\mug/cm^2$), thymol ($9.43\mug/cm^2$), DEET ($36.84\mug/cm^2$), and 3-carene ($42.11\mug/cm^2$). Against D. pteronyssinus adults, cuminaldehyde ($1.94\mug/cm^2$) was much more effective than benzyl benzoate ($6.50\mug/cm^2$) thymol ($6.92\mug/cm^2$), DEET ($17.79\mug/cm^2$), and 3-carene ($39.85\mug/cm^2$). These results indicate that the antimite activity of cumin seed oil could be caused by cuminaldehyde. Cuminaldehyde was about 3.9 and 3.4 times more toxic than benzyl benzoate against D. farinae and D. pteronyssinus adults, respectively. Therefore, further study is needed to confirm the findings of this study and the possibility of cuminaldehyde as a house dust mite control agent or a lead compound.

• 생약학회지
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• 제35권3호통권138호
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• pp.189-193
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• 2004

In order to find some lead compounds for the treatment of opportunistic infections of malaria and pathogenic microbes, an undescribed Indonesian sponge Agelas sp. collected at Manado, Indonesian Waters, was suggested containing active compounds. Crude ethanolic extract of the sponge exhibited significant in vitro antimalarial and antimicrobial activity against Plasmodium falciparum (D6 colne) with $IC_{5O}$ values of $8\;{\mu}/ml$ and against pathogenic microbes such as Candida albicans $(150\;{\mu}/ml)$, Cryptococcus neoformans $(<20\;{\mu}/ml)$, Staphylococcus aureus $25\;{\mu}/ml$, methicillin-resistant Staphylococcus aureus $(<20\;{\mu}/ml)$, and Pseudomonas aeruginosa $(<20\;{\mu}/ml)$. Active compound (5.0 mg) was isolated from the ethanolic extracts of the sponge and purified by using silica gel and ODS column, successively. Active compound was elucidated as dibromosceptrin $(C_{22}H_{24}Br_2N_{10}O_2)$ by detailed analysis of FTESI-MS and comparison of $^1H,\;^{13}C$, DEPT and HMQC NMR spectral data with those reported.

• Food Science and Biotechnology
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• 제16권2호
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• pp.218-222
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• 2007

The anticoagulant properties of Cinnamomum cassia bark-derived materials were evaluated against platelet aggregation induced by arachidonic acid (AA), collagen, platelet activating factor (PAF), or thrombin, and these effects were then compared to those of three commercially available compounds (cinnamic acid, cinnamyl alcohol, and aspirin). The active constituent obtained from C. cassia barks was isolated by silica gel column chromatography and high pressure liquid chromatography (HPLC), and was characterized as trans-cinnamaldehyde by MS, $^1H-NMR$, $^{13}C-NMR$, and IR spectroscopy. With regard to 50% inhibitory concentration ($IC_{50}$) values, cinnamaldehyde was found to effectively inhibit platelet aggregation induced by AA ($IC_{50},\;43.2\;{\mu}M$) and collagen ($IC_{50},\;3.1\;{\mu}M$). By way of comparison, cinnamaldehyde proved to be a significantly more potent platelet inhibitor against platelet aggregation induced by collagen than aspirin. The effect exerted by cinnamaldehyde against platelet aggregation induced by AA was 1.2 times less than that of aspirin. These results indicate that cinnamaldehyde may prove useful as a lead compound for the inhibition of platelet aggregation induced by AA and collagen.

• Journal of Microbiology and Biotechnology
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• 제15권2호
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• pp.434-437
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• 2005

During the screening for the inhibitors of cellulose biosynthesis as herbicides, we discovered a Streptomyces sp. A6497 with a selective antifungal activity against cellulose containing Phytophthora parasitica, but not against cellulose lacking Candida albicans. The inhibitor was isolated and identified, using a series of chromatographies. Based on structure analyses with UV spectrophotometry, mass and various NMR, the inhibitor was identified as sangivamycin. The compound exhibited strong antifungal activities against P. parasitica (MIC; 3.125 $\mu$g/ml). In particular, it showed strong herbicidal activities against various weeds in the greenhouse experiment. Taken together, these results suggest that sangivamycin is a useful lead compound for the development of new herbicides.