1. Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge141 83, Sweden
2. Magnetic Resonance Center and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, Sesto Fiorentino50019 , Florence, Italy
3. Department of Biochemistry and Biophysics, The Arrhenius Laboratories, Stockholm University, Stockholm106 91, Sweden
4. Department of Physical Organic Chemistry, Latvian Institute of Organic Synthesis, RigaLV-1006, Latvia