• Radiation Oncology Journal
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• v.17 no.4
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• pp.307-313
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• 1999

Purpose : To investigate the Presence of adaptive response by low dose radiation in murine tumors in relation to radiation induced apoptosis as well as related mechanism. Materials and Methods : Syngeneic murine tumors, OCa-I and HCa-l, were given 0.05 Gy pretreatment followed by therapeutic dose of 25 Gy radiation. Induction of apoptosis was analyzed for each treatment group. Regulating molecules of apoptosis, p53, Bcl-2, Bax, Bcl-X, were also analyzed by Western blotting. Results : In 0.05 Gy pretreatment group of OCa-I, 25 Gy-induced apoptosis per 1000 cells was 229, which was estimated at $30\%$ lower level than the expected (p<0.05). In contrast, this reduction in radiation induced apoptosis was not seen in HCa-l. In the expression of apoptosis regulating molecules, p53 increased in both tumors in response to radiation. Bcl-2 and Bax did not show significant change in both tumors however, the expression of Bcl-2 surpassed that of Bax in 0.05 Gy pretreatment group of OCa-l. Bcl-X was not expressed in OCa-l. In HCa-l, Bcl-X showed increased expression even with 0.05 Gy. Conclusion : Adaptive response by low dose radiation Is shown in one murine tumor, OCa-l, in relation to radiation induced apoptosis. Apoptosis regulating molecules including Bcl-2/Bax and Bcl-X, appear to related. This study shows an evidence that adaptive response is present, but not a generalized phenomenon in vivo.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.159-159
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• 2010

펄스 직류 전원 $BCl_3$/He 플라즈마를 사용하여 GaAs의 건식 식각을 연구하였다. 공정 변수는 가스 유량 (0~100% $BCl_3$ in $BCl_3$/He), 펄스 파워 ($450{\sim}600\;{\nu}$), 펄스 주파수 (100~250 KHz), 펄스 시간 ($0.4{\sim}1.2\;{\mu}s$)이었다. 식각 공정 후 식각률, 포토레지스트에 대한 식각 선택도, 표면 거칠기는 표면 단차 측정기를 이용하였다. 식각 공정 동안 플라즈마 광 특성 분석은 광학 발광분석기 (Optical emission spectroscopy)를 사용하였다. 실험 후 주사 전자 현미경을 이용, 식각 후 시료의 단면과 표면을 관찰하였다. 실험 결과에 의하면 1) 펄스 파워, 주파수, 시간을 고정 ($500\;{\nu}$, $0.7\;{\mu}s$, 200 KHz)하고 10% He 가스가 혼합되어 있는 조건에서 GaAs의 식각률이 순수한 $BCl_3$를 사용한 것보다 높았다. 이를 통해 식각 공정에서 일정량 이하의 He 혼합은 GaAs 식각률을 증가시키는 시너지효과가 있음을 알 수 있었다. 2) 그러나 약 20% 이상의 He 가스의 혼합은 GaAs의 식각 속도를 저하시켰다. 3) 10% He (9 sccm $BCl_3/1$ sccm He), 200 KHz 펄스 주파수, $0.7\;{\mu}s$ 펄스 시간의 조건에서 펄스 파워가 증가함에 따라 GaAs의 식각률 또한 선형적으로 증가하였다. 4) 특히, $600\;{\nu}$의 파워에서 식각률은 ${\sim}0.5\;{\mu}m/min$로 가장 높았다. 5) 표면 단차 측정기와 전자현미경을 이용하여 식각한 GaAs를 분석한 결과 10% He이 혼합되어 있는 조건에서는 우수한 수직 측벽과 매끈한 표면 (RMS roughness <1 nm)을 관찰할 수 있었다. 6) 10% He이 혼합된 $BCl_3$/He 펄스 직류 플라즈마 식각 후 XPS 분석결과에서도 기준 샘플과 비교하였을 때, 공정 후의 GaAs 표면이 화학적으로 깨끗하며 잔류물이 거의 검출되지 않았다. 위의 결과를 정리하였을 때, 펄스 직류 $BCl_3$/He 플라즈마는 GaAs의 식각에서 매우 우수한 공정 결과를 나타내었다.

• YAKHAK HOEJI
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• v.43 no.3
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• pp.385-390
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• 1999

Camptothecin (CPT) has been known to induce apoptosis in various cancer cell lines. To examine the intracellular apoptotic death signal initiated by CPT, we investigated the possible connection between caspase-3 activation and GSH depletion during CPT-induced apoptosis in HL-60 cells. Treatment of cells with $1{\;}{\mu}M$ CPT induced PARP cleavage accompanied by DNA fragmentation. z-VAD-fmk, a caspase-3 inhibitor, blocked the CPT-induced DNA fragmentation. Pretreatment of cells with N-acetylcysteine, a precursor of GSH biosynthesis, failed to inhibit CPT-induced PARP celavage and DNA gragmenatation. No significant changes in GSH depletion is not essential for caspase activation during CPT-induced apoptosis. We also investigated whether CPT-induced apoptosis is associated with changes of the levels of Bax and Bcl-2, two proteins involved in the control of apoptosis. Bcl-2 levels exhibited a late decrease compared with the kinetics of DNA fragmentation, whereas Bax levels increased more rapidly after CPT treatment. These results suggest that Bax plays more important role than Bcl-2 in inducing DNA fragmentation and may function upsteam of proteolytic activation of caspase-3 pathway in CPT-induced apoptosis.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.10a
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• pp.221-222
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• 2009

유도결합 플라즈마 (Inductively Coupled Plasma) 장비를 이용하여 각종 공정조건들에 따른 $TiO_2$의 식각 특성을 연구하였다. $BCl_3$/Ar 가스의 혼합비, 공정 압력 등을 공정 변수들로 정하였다. 공정 변수가 가스 혼합비일 경우 $BCl_3$ 가스의 비율이 25 % 일 경우 높은 식각률을 보였다. 또한 X-ray photoelectron spectroscopy를 이용하여 분석한 결과, $TiO_2$의 식각 메커니즘은 화학적인 영향보다는 물리적인 영향을 더 많이 받는다.

• Biomedical Science Letters
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• v.29 no.3
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• pp.201-205
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• 2023

Free adenine is mainly made during the polyamine synthesis in proliferating cells. Adenine molecule itself acts biological modulator in inflammation and cell death. In the previous report, we showed that adenine induces apoptotic cell death of B16-F10 mouse melanoma cells by eliciting of PARP and caspase 3 cleavages. In this study, we examined the adenine effect on other apoptotic molecules affecting caspase activation in B16-F10 melanoma cells. Adenine treatment make pro-apoptotic molecules active states. Bax/Bcl-2 ratio was increased and phosphorylation of mTOR and Akt was decreased in a dose dependent manner. These results showed the possibility that Bax/Bcl-2, Akt and mTOR are engaged in adenine induced apoptosis of melanoma cells.

• Transactions on Electrical and Electronic Materials
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• v.13 no.3
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• pp.157-161
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• 2012

In this study, we investigated the etching characteristics of ITO thin films and the effects of inert gases added to $Cl_2/BCl_3$ inductivity coupled plasma. The maximum etch rate of ITO thin film was 130.0 nm/min upon the addition of Ar (6 sccm) to the $Cl_2/BCl_3$ (4:16 sccm) plasma, which was higher than that with He or $N_2$ added to the plasma. The ion bombardment by $Ar^+$ sputtering was due to the relatively low volatility of the by-products formed in the $Cl_2/BCl_3$ (4:16 sccm) plasma. The surface of the etched ITO thin film was characterized by x-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). From the XPS results, it is concluded that the proper addition of Ar and He to the $Cl_2/BCl_3$ plasma removes carbon and by-products from the surface of the etched ITO thin film.

• Archives of Pharmacal Research
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• v.26 no.5
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• pp.405-410
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• 2003

Vitamin K-related analogs induce growth inhibition in various cancer cell lines. A naphthoquinone analog, termed 2,3-dichloro-5, 8-dihydroxy-1,4-naphthoquinone (DDN), induces apoptosis in human promyeloid leukemic HL-60 cells, and shows antitumor activity in vivo. Following treatment with DDN, evidence of apoptosis, including DNA fragmentation and cleavage of poly ADP ribose polymerase (PARP), was observed. DDN induced an upregulation of proapoptotic Bax protein, and Bid cleavage. Antiapoptotic Bcl-2 protein levels were not changed by DDN, but the expression of Bcl-xL was decreased. In addition, DDN reduced the mass of solid tumor in the Sarcoma 180 tumor-bearing mouse model. These results indicate that DDN exerts antitumor activity, which appears to be related to the induction of apoptosis by regulating Bcl-2 family proteins.

• Proceedings of the PSK Conference
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• 2000.10a
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• pp.207.1-207.1
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• 2000

• Proceedings of the PSK Conference
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• 2000.10a
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• pp.86-87
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• 2000

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.3
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• pp.254-261
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• 2005

The over-expression of Bcl-2 has greatly improved the culture period, specific growth rate, and maximum viable cell density of NS0 cells culture under low serum condition. Further analysis of these data suggests that a saturation model of the Monod type can be used to represent the relationships of specific growth rate and initial serum concentration. The ${\mu}_{max}$ and $K_s$ for the Bcl-2 cell line is $0.927day^{-1}\;and\;0.947\%(v/v)$ respectively, which are $21\%$ greate and $7\%$ lower respectively than its control counterpart. Study on the amino acid supplementation revealed that Bcl-2 cell lines possess greater improvement in the specific growth rate and maximum viable cell density compared to the control cell lines. A further increase in the amino acid supplementation has resulted a $17\%$ decrease in specific growth rate and no improvement in maximum viable cell density in the control culture. However, the Bcl-2 cell line exhibited a better growth characteristic in this culture condition compared to that of control cell lines. The higher specific growth rate and maximum viable cell density of the Bcl-2 cell line in medium fortified with serum and MEM EM suggested a more efficient nutrient metabolism compared to that in the control cell line. The low serum and amino acid utilisation rate and the higher cell yield may prove to be important in the development of serum/protein free culture.