1. a Department of Biomedical Engineering & Materials , College of Medicine, Soonchunhyang University , 366-1 Ssangyong dong, Cheonan , 330-090 , South Korea
2. b Department of Physiology , College of Medicine, Soonchunhyang University , 366-1 Ssangyong dong, Cheonan , 330-090 , South Korea