Conflicts of Interest
F.S. works for Philips Electronics Nederland B.V., which provided support in the form of salary, but did not have any additional role in the content, decision to publish, or preparation of this work. M.B., F.M., A.A., M.P., C.C., F.T., L.G. and P.C. declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as potential conflicts of interest.