About the Authors

Carol Shiels
Niall M Adams
Suhail A Islam
David A Stephens
Paul S Freemont

To whom correspondence should be addressed. E-mail: p.freemont@imperial.ac.uk

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

CS and PSF conceived the paper. CS collected and synthesised the material. NMA and DAS contributed to the statistical and quantitative content. SAI guided the imaging content.