Illustration (IMAGE) Moscow Institute of Physics and Technology Caption Biophysicists from MIPT and Vladimirsky Moscow Regional Clinical Research Institute have determined the optimal age of reprogrammed stem cells suitable for restoring heart tissue. It spans the period roughly from day 15 until day 28 of maturation. Credit Daria Sokol/MIPT Press Office Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.