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The optimal model of reperfusion injury in vitro using H9c2 transformed cardiac myoblasts
Euncheol Son,Dongju Lee,Chul-Woong Woo,Young-Hoon Kim 대한생리학회-대한약리학회 2020 The Korean Journal of Physiology & Pharmacology Vol.24 No.2
An in vitro model for ischemia/reperfusion injury has not been well-established. We hypothesized that this failure may be caused by serum deprivation, the use of glutamine-containing media, and absence of acidosis. Cell viability of H9c2 cells was significantly decreased by serum deprivation. In this condition, reperfusion damage was not observed even after simulating severe ischemia. However, when cells were cultured under 10% dialyzed FBS, cell viability was less affected compared to cells cultured under serum deprivation and reperfusion damage was observed after hypoxia for 24 h. Reperfusion damage after glucose or glutamine deprivation under hypoxia was not significantly different from that after hypoxia only. However, with both glucose and glutamine deprivation, reperfusion damage was significantly increased. After hypoxia with lactic acidosis, reperfusion damage was comparable with that after hypoxia with glucose and glutamine deprivation. Although highpassage H9c2 cells were more resistant to reperfusion damage than low-passage cells, reperfusion damage was observed especially after hypoxia and acidosis with glucose and glutamine deprivation. Cell death induced by reperfusion after hypoxia with acidosis was not prevented by apoptosis, autophagy, or necroptosis inhibitors, but significantly decreased by ferrostatin-1, a ferroptosis inhibitor, and deferoxamine, an iron chelator. These data suggested that in our SIR model, cell death due to reperfusion injury is likely to occur via ferroptosis, which is related with ischemia/reperfusion- induced cell death in vivo. In conclusion, we established an optimal reperfusion injury model, in which ferroptotic cell death occurred by hypoxia and acidosis with or without glucose/glutamine deprivation under 10% dialyzed FBS.
Euncheol Choi,Jae Ho Kim,Ok Bae Kim,Sang Jun Byun,Jin Hee Kim,Young Kee Oh 대한방사선종양학회 2018 Radiation Oncology Journal Vol.36 No.3
Purpose: We compared how doses delivered via two-dimensional (2D) intracavitary brachytherapy (ICBT) and three-dimensional (3D) ICBT varied anatomically. Materials and Methods: A total of 50 patients who received 30 Gy of 3D ICBT after external radiotherapy (RT) were enrolled. We compared the doses of the actual 3D and 2D ICBT plans among patients grouped according to six anatomical variations: differences in a small-bowel V 2Gy , small bowel circumference, the direction of bladder distension, bladder volume, sigmoid V 3.5Gy , and sigmoid circumference. Seven dose parameters were measured in line with the EMBRACE recommendations. Results: In terms of bladder volume, the bladder and small-bowel D 2cc values were lower in the 150–250 mL bladder volume subgroup; and the rectum, sigmoid, and bladder D 2mL values were all lower in the >250 mL subgroup, for 3D vs. 2D ICBT. In the sigmoid V 3.5Gy >2 mL subgroup, the sigmoid and bladder D 2mL values were significantly lower for 3D than 2D ICBT. The bladder D2mL value was also significantly lower for 3D ICBT, as reflected by the sigmoid circumference. In patients with a small bowel V 2.0Gy >10 mL or small bowel circumference >15%, most dose parameters were significantly lower for 3D than 2D ICBT. The bladder distension direction did not significantly affect the doses. Conclusion: Compared to 2D ICBT, a greater bladder volume can reduce the internal 3D ICBT organ dose without affecting the target dose.
Target and Background Area Weighted Tracking Algorithm
Euncheol Choi,Young Duk Kim,Suk-Ho Lee,Moon Gi Kang 대한전자공학회 2008 ITC-CSCC :International Technical Conference on Ci Vol.2008 No.7
Recently, kernel-based tracking algorithms such as the mean shift tracking algorithm has been proposed. However, there exists an inherent instability problem which is due to the use of an isotropic kernel for spatiality. In this paper, In this paper, we propose a new tracking algorithm : the weighted mean of the centroids corresponding to each color bin of the target. The weight is determined by the area of the color bins and background colors. The tracking based on proposed model contains spatial information on the distribution of the colors, is rather insensitive to the loss of pixels and change in the number of pixels, and takes the colors into account according to the area they cover in the initial target region. Due to these properties, it possible to track the target in difficult conditions such as low-frame-rate environment, severe partial occlusion and partial color change environment. Furthermore, the target position estimation is executed in a one step computation, which makes the algorithm fast. We compare the stableness of the proposed tracking scheme with the conventional mean shift algorithm experimentally.
Motion Tracking Based on Background Color Rejective Centroids Shifting
Euncheol Choi,Jong Hyun Park,Moon Gi Kang 대한전자공학회 2008 ICEIC:International Conference on Electronics, Inf Vol.1 No.1
In this paper, we propose a new tracking algorithm : the weighted mean of the centroids corresponding to each color bin of the target. The weight is determined by the area of the color bins and background colors. The tracking based on proposed model contains spatial information on the distribution of the colors, is rather insensitive to the loss of pixels and change in the number of pixels, and takes the colors into account according to the area they cover in the initial target region. Due to these properties, it possible to track the target in difficult conditions such as low-frame-rate environment, severe partial occlusion and partial color change environment. Furthermore, the target position estimation is executed in a one step computation, which makes the algorithm fast. We compare the stableness of the proposed tracking scheme with the conventional mean shift algorithm experimentally.
Euncheol Choi,Jin Hee Kim,Ok Bae Kim,Mi Young Kim,Young Ki Oh,Sung Gyu Baek 대한방사선종양학회 2016 Radiation Oncology Journal Vol.34 No.2
Purpose: To identify possible predictors of pathologic complete response (pCR) of rectal cancer after preoperative concurrent chemoradiotherapy (CCRT). Materials and Methods: We conducted a retrospective review of 53 patients with rectal cancer who underwent preoperative CCRT followed by radical surgery at a single center between January 2007 and December 2012. The median radiotherapy dose to the pelvis was 54.0 Gy (range, 45.0 to 63.0 Gy). Five-fluorouracil-based chemotherapy was administered via continuous infusion with leucovorin. Results: The pCR rate was 20.8%. The downstaging rate was 66%. In univariate analyses, poor and undifferentiated tumors (p =0.020) and an interval of ≥7 weeks from finishing CCRT to surgery (p = 0.040) were significantly associated with pCR, while female gender (p = 0.070), initial carcinoembryonic antigen concentration of <5.0 ng/dL (p = 0.100), and clinical stage T2 (p = 0.100) were marginally significant factors. In multivariate analysis, an interval of ≥7 weeks from finishing CCRT to surgery (odds ratio, 0.139; 95% confidence interval, 0.022 to 0.877; p = 0.036) was significantly associated with pCR, while stage T2 (odds ratio, 5.363; 95% confidence interval, 0.963 to 29.877; p = 0.055) was a marginally significant risk factor. Conclusion: We suggest that the interval from finishing CCRT to surgery is a predictor of pCR after preoperative CCRT in patients with rectal cancer. Stage T2 cancer may also be an important predictive factor. We hope to perform a robust study by collecting data during treatment to obtain more advanced results.
박은철(Euncheol Park),홍순석(Soonseok Hong),장재덕(Jaeduk Jang),주인식(Insik Joo) 한국자동차공학회 2005 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2005 No.5_2
This paper presents the noise analysis technique and the radiation sound improve method for the torque converter of auto transmission vehicles, and the experiment of radiation sound measurement proves the method to be adequate. The ambient noise of the torque converter is not the form of the resonance coming from a specific rotational frequency. but reaction to frequency ingredient sensitively to appear the Order line. This article analyzes the occurrence factor of the ambient noise and proves that the ambient noise of the torque converter depends on numbers of the impeller blades. This paper proves that the ambient noise is reduced after increasing the number of blades, and presents the adequacy of this method.
과학기술시대의 책임윤리를 찾아서: 한스 요나스의 『책임의 원칙』을 중심으로
김은철(Euncheol Kim),송성수(Sungsoo Song) 한국공학교육학회 2012 공학교육연구 Vol.15 No.1
This paper deals with metaphysical aspects of responsibility focusing on Hans Jonas s Das Prinzip Veranwortung as an attempt to further the discussion on the responsibility of scientists and engineers. After the examination on the necessity of new ethics reflecting the characteristics of contemporary science and technology, the philosophical foundation and major themes of Jonas s future-oriented ethics, i.e. responsibility ethics are analysed. Jonas argued new ethics should consider man and nature simultaneously based on the unification of being and what should be, and presented collectivity, continuity, and future-orientation as a basis of responsibility ethics. In conclusion, this paper suggests implications of Jonas s argument for science and technology ethics such as sustainability, precautionary principle, and responsibility of creator.