Tim Antonius completed his MSc in Medicine at the Radboud University in Nijmegen, the Netherlands. Fascinated by human physiology, especially the physiology of the transition after birth, he completed his pediatric residency and fellowship in neonatology in 2008. Tim joined the department of neonatology of the Radboud University Medical Centre where he is currently working on explanatory models in neonatology. Specializing in neonatal circulation, ECMO and acute care neonatology, Tim got involved in simulation and modeling in 2007. Not entirely happy with the current state of simulation in medicine he started designing his own simulators which resulted in a neonatal and an ECMO simulator which has won several prizes. Realizing that mathematical models of human physiology are certainly able to explain complex physiological systems but might also be able to predict effects of interventions, Tim developed an integrated mathematical model of a term born neonate. This model not only describes the transition from fetus to newborn but it is also able to model several congenital heart and lung conditions. Physicians can use the models to enhance case discussions, explain complex clinical problems and test the possible effects of real life clinical interventions.