1. Molecular Logic Gate Laboratory, Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), 373-1 Guseong-dong, Yuseong-gu, Daejeon, 305-701, Republic of Korea, and Department of Anatomy and Neurobiology, Medical Research, Center for Neural Dysfunction, Institute of Health Science, School of Medicine, Gyeongsang National University, 92 Chilam-dong, Jinju, Gyeongnam 660-751, Republic of Korea