a
Department of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
E-mail: n.long@imperial.ac.uk
;
Fax: +44 (0)20 7594 5804
;
Tel: +44 (0)20 7594 5781
b
Division of Brain Sciences, Department of Medicine, Imperial College London, Du Cane Road, London, UK
E-mail: f.gavins@imperial.ac.uk
;
Fax: +44 (0)20 7594 6548
;
Tel: +44 (0)20 7594 6586
c
Biological Imaging Centre, Imperial College London, Du Cane Road, London, UK
d
GE Healthcare, The Grove Centre, White Lion Road, Amersham, Buckinghamshire, UK