Prof. Dr. Hans Kroha (IMAGE) University of Bonn Caption mit Studierenden. Credit Foto: Bernadett Yehdou/Uni Bonn Usage Restrictions This image may be used together with the press release. License Original 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.