1. Department of Neurobiology, Care Sciences and Society (NVS), Karolinska Institutet, Neo, Blickagången 16, Huddinge 141 52, Sweden
2. Department of Materials Science and Engineering, The University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield S1 3JD, United Kingdom
3. Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Uppsala 750 07, Sweden