• 대한흉부심장혈관외과학회:학술대회논문집
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• 대한흉부외과학회 1993년도 제25차년차학술대회 및 총회
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• pp.128-128
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• 1993

• 대한의용생체공학회:의공학회지
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• 제26권6호
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• pp.393-398
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• 2005

An electromechanical type is the most useful mechanism in the various pumping mechanisms. It, however, requires a movement converting system including a ball screw, a helical cam, or a solenoid-beam spring, which makes the device complex and may lessen reliability. Thus, the authors have hypothesized that an electromagnetic actuator mechanism can eliminate the movement converting system and that thereby enhance the mechanical reliability and operative simplicity of an electro­pneumatic pump. The purpose of this study was to show a novel application of electromagnetic actuator mechanism in pulsatile pump and to provide preliminary data for further evaluations. The electromagnetic actuator consists of stators with a single winding excitation coil and movers with a high energy density neodymium-iron-boron permanent magnet. A 0.5mm diameter wire was used for the excitation coil, and 1000 turns were wound onto the stators core with parallel. A prototype of extracorporeal electro-pneumatic pump was constructed, and the pump performance tests were performed using a mock system to evaluate the efficiency of the electromagnetic actuator mechanism. When forward and backward electric currents were supplied to the excitation coil, the mover effectively moved back and forth. The nominal stroke length of the actuator was 10mm. The actuator dimension was 120mm in diameter and 65mm in height with a mass of 1.4kg. The prototype pump unit was 150mm in diameter, 150mm in thickness and 4.5kg in weight. The maximum force output was 70N at input current of 4.5A and the maximum pump rate was 150 beats per minute. The maximum output was 2.0 L/minute at a rate of 80bpm when the afterload was 100mmHg. The electromagnetic actuator mechanism was successfully applied to construct the prototype of extracorporeal electro­pneumatic pump. The authors provide the above results as a preliminary data for further studies.

• BMB Reports
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• 제51권9호
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• pp.474-479
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• 2018

Cisplatin is one of the most effective chemotherapeutic drugs used in the treatment of HCC, but many patients will ultimately relapse with cisplatin-resistant disease. Used in combination with cisplatin, resveratrol has synergistic effect of increasing chemosensitivity of cisplatin in various cancer cells. However, the mechanisms of resveratrol enhancing cisplatin-induced toxicity have not been well characterized. Our study showed that resveratrol enhances cisplatin toxicity in human hepatoma cells via an apoptosis-dependent mechanism. Further studies reveal that resveratrol decreases the absorption of glutamine and glutathione content by reducing the expression of glutamine transporter ASCT2. Flow cytometric analyses demonstrate that resveratrol and cisplatin combined treatment leads to a significant increase in ROS production compared to resveratrol or cisplatin treated hepatoma cells alone. Phosphorylated H2AX (${\gamma}H2AX$) foci assay demonstrate that both resveratrol and cisplatin treatment result in a significant increase of ${\gamma}H2AX$ foci in hepatoma cells, and the resveratrol and cisplatin combined treatment results in much more ${\gamma}H2AX$ foci formation than either resveratrol or cisplatin treatment alone. Furthermore, our studies show that over-expression of ASCT2 can attenuate cisplatin-induced ROS production, ${\gamma}H2AX$ foci formation and apoptosis in human hepatoma cells. Collectively, our studies suggest resveratrol may sensitize human hepatoma cells to cisplatin chemotherapy via gluta${\gamma}H2AX$mine metabolism inhibition.

• 대한의용생체공학회:의공학회지
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• 제26권5호
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• pp.337-341
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• 2005

Blood pulsation has been reported to have an advantageous effect on extracorporeal blood circulation. However, the study of pulsatile blood flow in renal replacement therapy is very limited. The in-vitro experimental results of pulsatile blood flow on ultrafiltration, when compared with the conventional roller pump, are described in this paper. Methods: Blood flow rate (QB) and transmembrane pressure (TMP) were considered as regulating factors that have an influence on ultrafiltration. Experiments were performed under the condition of equal TMP and OB in both pulsatile and roller pump groups, Several kinds of hollow fiber dialyzers were tested using distilled water containing chemicals as a blood substitute. Mean TMP (mTMP) varied from 10 to 90mmHg while the QB was 200ml/min. Results: Ultrafiltration rate (QUF) was found to be linearly proportional to TMP, whereas QB had little influence on QUF. In addition, QUF was higher in the pulsatile group than the roller pump group at the identical TMP. Conclusion: In the controlled test, QUF increased solely as a consequence of blood pulsation, which implies that the pulse frequency represents an additional and important clinical variable during renal replacement therapy.

• Clinical and Experimental Pediatrics
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• 제52권8호
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• pp.856-861
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• 2009

Cardiopulmonary arrest has long been accepted as an unquestionable definition of death. An advent of cardiopulmonary resuscitation and artificial ventilation along with the development of organ transplantation has prompted the emergence of the concept of brain death. The criteria for brain death are based mainly on the clinical examination of coma, apnea and total loss of brain stem function. Although organ transplantation by donor brain death has increased in Korea over recent years, there is still a substantial shortage of donor organs compared to the demand. Improvement of government policies and changes of social culture for organ donation are needed for the activation of organ transplantation by donor brain death. Pediatricians have an important role for the search of potential donors in cases of brain death and optimal medical care for successful organ transplantation.

• 한국정밀공학회지
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• 제17권11호
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• pp.5-16
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• 2000

• 멤브레인
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• 제33권2호
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• pp.61-69
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• 2023

최근 COVID-19로 인해 증가한 급성 폐부전 중증환자 치료를 위한 인공폐 기술의 필요성이 부각되었다. 또한, 빠르게 진행되고 있는 인구고령화는 인공장기(artificial organ, AO) 기술에 대한 높은 수요를 불가피하게 만들고 있다. 분리막은폐, 신장, 간 및 췌장을 포함한 많은 AO 기기의 핵심 부품이다. 특히 인공폐(artificial lung, AL) 기술은 지난 50년간 빠르게 발전해왔지만, 장기부전 환자의 생존율은 50% 내외로 여전히 낮은 편이다. 현재 대부분의 AL 관련문헌은 임상결과에 집중되어 있으며, AL 분리막의 개발연구는 매우 부족한 편이다. 이에 대한 원인 중 하나는 AL 기술이 생명공학을 포함하여 고분자 화학 및 분리공정 기술을 아우르는 융합적 기술개발을 요구하기 때문인 것으로 판단된다. 본 총설에서는 헬스케어산업에서 AL 분리막 기술의 역할과 기술개발이 필요한 난제들을 정리하였다. 특히, 분리막 소재의 혈액적합성, 분리성능, 모듈 디자인 및 공정 구성 측면에서 다양한 연구개발이 필요하다는 부분을 강조하고자 한다.

• 대한의용생체공학회:의공학회지
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• 제20권3호
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• pp.237-249
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• 1999

• 한국멀티미디어학회논문지
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• 제24권8호
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• pp.1000-1011
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• 2021

In recent years, using Deep Learning methods to apply for medical and biomedical image analysis has seen many advancements. In clinical, using Deep Learning-based approaches for cancer image analysis is one of the key applications for cancer detection and treatment. However, the scarcity and shortage of labeling images make the task of cancer detection and analysis difficult to reach high accuracy. In 2015, the Unet model was introduced and gained much attention from researchers in the field. The success of Unet model is the ability to produce high accuracy with very few input images. Since the development of Unet, there are many variants and modifications of Unet related architecture. This paper proposes a new approach of using Unet++ with pretrained EfficientNet as backbone architecture for breast tumor cell nuclei segmentation and uses the multi-organ transfer learning approach to segment nuclei of breast tumor cells. We attempt to experiment and evaluate the performance of the network on the MonuSeg training dataset and Triple Negative Breast Cancer (TNBC) testing dataset, both are Hematoxylin and Eosin (H & E)-stained images. The results have shown that EfficientUnet++ architecture and the multi-organ transfer learning approach had outperformed other techniques and produced notable accuracy for breast tumor cell nuclei segmentation.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2021년도 제64차 하계학술대회논문집 29권2호
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• pp.343-345
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• 2021

본 논문에서는 4D 프린팅을 이용한 인공장기이식에 대해 소개한다. 여러 외부적 요인에 대처할 수 없었던 3D 바이오 프린팅의 단점을 보완하여 자가변환 및 자가조립이 가능한 재료를 3D프린터로 찍어낸 다음, 그 물체가 주변환경에 의해 스스로 모양이 변화하는 기술인 4D 프린팅을 이용한다. 또한, 4D 프린팅은 변형이 가능한 특수 소재를 사용함으로써 시간이 지나면 출력한 결과물의 모양이 변하게 되고, 시간 및 온도·습도·압력 등의 외부적인 요인에 스스로 능동적으로 대처할 수 있다. 본 논문에서는 4D 프린팅 기술로 제작한 작은 인공장기를 인체에 삽입함으로써 수술 후 감염 및 합병증 등의 부작용을 최소화할 수 있고 수술 시간을 크게 단축할 수 있다는 면에서 우수함을 보인다.