1. Laboratory of Pharmacology, College of Veterinary Medicine, Seoul National University, Seoul 151-742, Korea.
2. Research Institute and Hospital, National Cancer Center, Goyang 410-769, Korea.
3. Department of Chemistry, Soongsil University, Seoul 156-743, Korea.
4. Department of Mechatronics, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea.