1. Department of Chemistry, College of Natural Sciences, Kyungpook National University, Taegu 702‐701, South Korea, Fax: +82‐53‐950‐6330, http://webbuild.knu.ac.kr/~ghlee
2. Department of Molecular Medicine and Medical & Biological Engineering, School of Medicine, Kyungpook National University, Taegu 702‐701, South Korea
3. Department of Biology Education, Teachers' College, Kyungpook National University, Taegu 702‐701, South Korea
4. Department of Applied Chemistry, College of Engineering, Kyungpook National University, Taegu 702‐701, South Korea
5. Laboratory of Nuclear Medicine Research, Molecular Imaging Research Center, Korea Institute of Radiological Medical Science, Seoul 139‐706, South Korea