1. Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro,
Nam-gu, Pohang, Kyungbuk 790-784, Korea
2. PHI Biomed Company, 175 Yeoksam-ro, Gangnam-gu, Seoul 06247, South Korea
3. Department of Internal Medicine, College of Medicine, The Catholic University of Korea, 505 Banpo-dong, Seocho-gu, Seoul 137-701, Korea