1. Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, Texas 77843, United States
2. NMR Research Unit, Faculty of Science, University of Oulu, P.O. Box 3000, 90014 Oulu, Finland
3. Department of Electrical Engineering, Center for Hyperpolarization in Magnetic Resonance, Technical University of Denmark, Building 349, DK-2800 Kgs Lyngby, Denmark