1. Center for Proteomics and Metabolomics, Leiden University Medical Center, Postbus 9600, 2300 RC Leiden, The Netherlands
2. Institute of Marine Research, P.O. Box 1870
Nordnes, 5817 Bergen, Norway
3. National Institute for Public Health and the Environment, 3720 BA Bilthoven, The Netherlands
4. Department of Human Genetics, Leiden University Medical Center, Postbus 9600, 2300 RC Leiden, The Netherlands
5. National Institute of Standards and Technology, Charleston, South Carolina 29412, United States