1. Department of Paediatrics I, Neonatology, University Hospital Essen, University Duisburg-Essen, 45147 Essen, Germany
2. Institute of Physiology, University of Duisburg-Essen, 45147 Essen, Germany
3. Department of Anaesthesiology and Intensive Care Medicine, Charité-Universitätsmedizin Berlin, Campus Virchow-Klinikum, 13353 Berlin, Germany
4. Division of Child Growth and Development, Department of Paediatrics, University of Geneva, 1205 Geneva, Switzerland
5. Laboratory of Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
6. Institute of Medical Psychology and Behavioral Immunobiology, University Hospital Essen, University Duisburg-Essen, 45147 Essen, Germany
7. Department of Neonatology, Charité-Universitätsmedizin Berlin, 13353 Berlin, Germany