1. Department of Neurological Surgery, Keck School of Medicine, University of Southern California, and Department of Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
2. Section of Neurosurgery, Department of Clinical Neuroscience, Karolinska Institutet and Hospital, 171 76 Stockholm, Sweden
3. Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033
4. Institute for Surgical Research, and Department of Neurosurgery, Rikshospitalet, Univerity of Oslo, Norway
5. McCollum-Corcoran Professor and Chairman, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125