D-shaped Loops (IMAGE) Rice University Caption Formation of D-shaped loops is due to the misfusion of PAN-based nanoribbons, according to a new theory by scientists at Rice University. Credit Nitant Gupta and Evgeni Penev/Rice University Usage Restrictions For news reporting purposes only. 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.