• Biomolecules & Therapeutics
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• v.8 no.1
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• pp.22-26
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• 2000

In order to study the cytotoxic properties of sesquitepenes, dehydrocostus lactone (DL) and costunolide from Saussurea lappa, cytotoxicity was measured by SRB method using various human cancer cell lines. Dehydrocostus lactone(DL) and costunolide exhibited significant cytotoxicity against A-549, SK-OV-3, SK-MEL-2, XF-498 and HCT 15 cells. The U937 human leukemia cells treated with DL showed several apoptotic evidences like chromosome condensation and formation of apoptotic bodies. From the results of FACS analysis, early apoptosis was observed by phosphatidylserine externalization detected by annexin V-FITC. Furethermore, these studies determined hypodiploid contents and effects on the cell phase distribution of DL-treated U937 cells. After exposure of U937 cells to $30\mu\textrm{M}$ DL effectively led to G2/M modified cell cycle distribution within 24hr. These observations suggest that DL can be used efficiently for the cancer treatment.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05b
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• pp.181-185
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• 1998

모의 혼합산화물인 (U,Ce)O$_2$ 에 dopant 인 Li$_2$O 와 SiO$_2$ 를 첨가한 소결체의 압축크립변형거동을 수소분위기, 온도 1773K 에서 응력(10-120MPa)을 변화시켜 조사하였다. Dopant 를 첨가할 경우 정상상태 크립변형속도는 첨가하지 않은 경우보다 크게 증가하는 것으로 나타났다. 증가한 원인으로는 Li$_2$O 를 첨가한 경우 우라늄 확산계수의 증가에 기인되며, SiO$_2$ 를 첨가한 경우에는 SiO$_2$ 가 glassy phase 로 입계에 위치하여 입계이동이 용이하게 되어 정상상태 크립변형속도가 증가한 것으로 사료된다. 또한 저응력구간에서 (U,Ce)O$_2$ 의 크립활성화에너지는 109.6 kcal/mol 로 $UO_2$ 의 크립활성화에너지(94.2kca1/mol)보다 더 크게 나타났다.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.487-490
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• 2002

In this paper, we report a novel way to evaluate the anticlinic interlayer coupling coefficient U between smectic layers of an antiferroelectric liquid crystal, by utilizing a small field-induced perturbation of the molecular orientation. U was found to exhibit an unusual "S-shaped" dependence on temperature, with values ranging between $0.4{\times}10^4$ and $0.4{\times}10^{-1}$ erg $cm^{-3}$ over a 10$^{\circ}C$ temperature range below smectic A-smectic $C_A$ phase transition temperature. The results are good agreement with estimates for U based upon the threshold field for the onset of solitary waves, and provide strong supporting the low-field regime for the single Fourier component model.

• Journal of Life Science
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• v.15 no.6 s.73
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• pp.994-1004
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• 2005

The dihydrofolate reductase (dhfr) promoter contains cis-acting element for the transcription factors Spl and E2F. Transcription of dhfr gene shows maximal activity during the Gl/S phase of cell cycle. The member of the Spl transcriptional factor family can act as both negative and positive regulators of gene expression. There was a report that Spl-Rb and E2F4-pl30 complexes cooperate to establish stable repression of dhfr gene expression in CHOC400 cells. Here, we examined the role of HDAC in dhfr, cyclin E, and cyclin A gene regulation using the histone deacetylation inhibitor, trichostatin A (TSA) in U2OS and C33A cells, a Rb-positive human osteosarcoma cell line, and a Rb-negative cervical carcinoma cell line, respectively. When the dhfr promoter constructs were applied in U2OS cells, TSA markedly stimulated over 14-fold of dhfr promoter activity through dhfr-Spl sites by the deletion of an E2F element. In contrast, the deletion of dhfr-Spl binding sites completely abolished promoter stimulation by TSA. The dhfr promoter activity including dhfr-Spl sites increased only 2-fold in C33A cells. Promoter activity containing only dhfr-E2F site did not have much effect by the treatment of TSA in both U2OS and C33A cells. On the other hand, treatment with TSA induced significantly mRNA expression of dhfr and cyclin E, whereas levels of cyclin A decreased in U2OS cells, but had no effect in C33A cells. These results indicate that TSA have contradictory effect, activation of dhfr and cyclin E genes on Gl phase, and down-regulation of cyclin A on G2 phase through transcriptional regulation in U2OS cells.

• Proceedings of the Materials Research Society of Korea Conference
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• 2008.11a
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• pp.32.1-32.1
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• 2008

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.539-540
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• 2009

• Proceedings of the Korean Ceranic Society Conference
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• 2003.04a
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• pp.38.2-38
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• 2003

• Proceedings of the Korean Ceranic Society Conference
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• 2003.04a
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• pp.185.2-185
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• 2003

• Proceedings of the Korean Ceranic Society Conference
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• 2000.10a
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• pp.90.1-90
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• 2000

• Proceedings of the Korean Ceranic Society Conference
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• 2000.10a
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• pp.119.2-119
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• 2000