University of Florida radiologist Keith Peters holds a fluid-filled pouch next to a replica human skull that, his research partner's tests show, protect the brain from shearing force of hits on helmets in their lab at the University of Florida in Gainesville, Florida, January 13, 2014. Subhash and Peters believe they have come up with a low-cost way to improve football helmets and better protect players against the glancing blows that experts say contribute to most concussions - fluid-filled pouches for football helmets to prevent concussions. REUTERS/Steve Johnson (UNITED STATES - Tags: EDUCATION HEALTH SPORT FOOTBALL SCIENCE TECHNOLOGY)