Niklas Zethraeus, Karolinska Institutet (IMAGE) Karolinska Institutet Caption This is Niklas Zethraeus. Photo: Stefan Zimmerman. Credit Stefan Zimmerman Usage Restrictions May only be used in connection to reports about this study. 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.