[1] Univ Nebraska Lincoln, Dept Comp Sci & Engn, Lincoln, NE 68588 USA
[2] Univ Essex, Sch Comp Sci & Elect Engn, Colchester CO4 3SQ, Essex, England
[3] Oslo Univ Hosp, Intervent Ctr, N-0372 Oslo, Norway
[4] Michigan State Univ, Dept Pharmacol & Toxicol, E Lansing, MI 48824 USA
[5] Univ Oulu, Biochem & Mol Med, Oulu 90570, Finland
[6] Norwegian Univ Sci & Technol, Dept Elect Syst, N-7491 Trondheim, Norway