1. Department of Cardiovascular Surgery, Oita University, Oita 879-5593, Japan
2. Department of Clinical Engineering, Oita University Hospital, Oita 879-5593, Japan
3. Institute of Frontier Science and Technology, Okayama University of Science, Okayama 700-0005, Japan
4. Department of Mechanical Engineering, Faculty of Engineering Science, Kansai University, Osaka 564-8680, Japan
5. Osaka Laboratory, Biotube Co., Ltd., Osaka 565-0842, Japan