• Journal of the Korean Ceramic Society
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• v.37 no.11
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• pp.1097-1104
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• 2000

MOD(Metal-Organic-Decomposition)법에 의해 $Y_2$O$_3$버퍼층에 Pt/TiO$_2$/SiO$_2$/Si 기판 위에 제조한 후, 그 표면 위에 졸-겔 방법으로 YMnO$_3$박막을 형성하였다. 기판의 종류와 수화조건 변화가 YMnO$_3$박막의 결정화 거동에 미치는 영향을 고찰하였으며, 또한 $Y_2$O$_3$버퍼층 유.무에 따른 Mn의 산화상태를 확인하고 이에 따른 유전특성 변화를 연구하였다. $Y_2$O$_3$버퍼층을 삽입하지 않고 직접 기판 위에 형성한 YMnO$_3$박막의 결정상은 기판의 종류 및 Rw 변화에 관계없이 orthorhombic 구조임이 확인되었다. 반면, $Y_2$O$_3$버퍼층 위에 형성된 YMnO$_3$박막의 경우에는 Rw($H_2O$/alkoxide mole ratio)가 0~6 범위 내에서 낮아질술고 hexagonal 결정상 성장에 유리하였으며, 또한 Pt(111)/TiO$_2$/SiO$_2$/Si 기판이 Ptd(200)/TiO$_2$/SiO$_2$/Si에 비하여 결정상 형성에 용이하였다. $Y_2$O$_3$버퍼층은 YMnO$_3$결정상 내에서 $Mn^{4+}$ 이온형성을 억제함으로써 누설전류밀도가 크게 감소되는 효과를 주었으며, 동시에 강유전 특성을 지닌 hexagonal 결정상 형성에 유리하게 작용하였다. 결론적으로, $Y_2$O$_3$는 Pt가 코팅된 Si 기판 위에 YMnO$_3$박막 제조시 그 강유전 특성을 향상시켜주는 우수한 버퍼층 재료임을 확인하였다.

• Molecules and Cells
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• v.21 no.1
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• pp.104-111
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• 2006

Gene therapy with nonviral vectors using the suicide gene/prodrug activating system of herpes simplex virus type-1 thymidine kinase (HSV1-TK)/ganciclovir (GCV) is inefficient in killing malignant tumor cells due to two major factors: (a) an unsatisfactory bystander effect; (b) short-lived expression of the protein. To study the capacity of the protein transduction domain (PTD) of HIV-1 TAT protein to enhance HSV1-TK/GCV cancer gene therapy, we constructed three fusion proteins TAT-TK, TK-TAT and TK. TAT-TK retained as much enzyme activity as TK, whereas that of TK-TAT was much lower. TAT-TK can enter HepG2 cells and much of it is translocated to the nucleus. The transduced HepG2 cells are killed by exogenously added GCV and have bystander effects on untransduced HepG2 cells. Most importantly, the introduced recombinant protein is stable and remains functional for several days at least, probably because nuclear localization protects it from the cytoplasmic degradation machinery and provides access to the nuclear transcription machinery. Our results indicate that TAT fusion proteins traffic intercellularly and have enhanced stability and prodrug cell killing activity. We conclude that TAT has potential for enhancing enzyme prodrug treatment of liver cancers.

• Journal of Life Science
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• v.16 no.4
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• pp.691-698
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• 2006

Phospholipase D (PLD) is known to play an important role in a variety of cells. However, little is known about $CoCl_2-mediated$ PLD signaling. In this study we demonstrated for the first time that $CoCl_2$ stimulates PLD activity and increases expression of cyclooxygenase-2 (COX-2), which is known to mediate inflammatory reaction. $CoCl_2-induced$ PLD activity was assessed by measuring the formation of $[^3H]$ phosphatidylbutanol (PtdBut), the product of PLD-mediated transphosphatidylation, in the presence of 1-butanol. To study mechanism of PLD signaling induced by $CoCl_2$, U87 human glioblastoma cells were stimulated by $CoCl_2$ and regulators of PLD activity induced by $CoCl_2$ were investigated using several inhibitors of signaling proteins. Moreover, PLD activation by $CoCl_2$ increased not only expression of COX-2 protein but also COX-2 promoter activity. In summary, these results suggest that $CoCl_2$ increases expression of COX-2 protein via PLD in human U87 glioblastoma cells.

• 재활복지
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• v.22 no.1
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• pp.141-156
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• 2018

The purpose of this study was to examine changes in the swallowing function with chronic stroke patient. Ten chronic stroke patients with dysphagia followed up for 3 months. Eight normal age match subjects were also participated. A total of 18 participated in this study and they were classified into two groups (stroke patient group and normal control group). Participants underwent videofluoroscopic swallowing examination. The swallowing function was evaluated over time. Oral transit duration, pharyngeal transit duration, laryngeal response duration, Modified Barium Swallowing Impairment Profile ($MBSImP^{TM(c)}$), and Functional Oral Intake Scale (FOIS) were applied. Chronic stroke patient group were showed significantly longer oral transit duration, pharyngeal transit duration and laryngeal response duration than normal control group at baseline. After 3 months in stroke patient group, the mean oral components score of MBSImP (1~5) significantly decreased and the mean score on FOIS increased compared to baseline. In conclusion, oral swallowing function and oral intake function improved by the 3 month evaluation. These results describe changes in swallowing function with chronic stroke patients over time and provide basic informations to understand dysphagia.