Yihai Cao, Karolinska Institutet (IMAGE) Karolinska Institutet Caption This is Professor Yihai Cao at the Karolinska Institutet in Stockholm, Sweden. Credit John Sennett Usage Restrictions This image may only be used in connection to reports about the current findings by Prof Cao and colleagues. Credit must be given to the photographer when published. 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.