1. Department of Mathematical Sciences, Durham University, Durham DH1 3LE, United Kingdom
2. Institute for Cell and Molecular Bioscience, Medical School, University of Newcastle, Newcastle upon Tyne, NE2 4HH, United Kingdom
3. Department of Biosciences Durham University, Durham DH1 3LE, United Kingdom
4. Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom