1. Case Complex Systems Biology Center, Electrical Engineering and Computer Science Department, Case Western Reserve University, Cleveland, OH 44139, U.S.A.
2. Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), 335 Gwahangno, Yuseong-gu, Daejeon 305-701, Republic of Korea
3. The Hamilton Institute, National University of Ireland, Maynooth, Co. Kildare, Ireland