1. Department of ChemistryIowa State University Ames IA 50011 USA
2. US DOE Ames Laboratory Ames IA 50011 USA
3. Genentech Inc. South San Francisco CA 94080 USA
4. Center of Interdisciplinary Magnetic Resonance (CIMAR)National High Magnetic Field Laboratory (NHMFL) Tallahassee FL 32310 USA