SPC Peter Johnson, left, and SPC Daniel Oladejo, biomedical science technicians with the U.S. Army Institute of Surgical Research, make adjustments to the shock tube in February at Fort Sam Houston, Texas. The shock tube is designed to simulate exposure to explosions similar to what Soldiers may encounter in combat, generating data that are crucial to research aimed at caring for Soldiers who suffer from conditions affecting their eyes. (U.S. Army photo by SGT Aaron Ellerman, 204th Public Affairs Detachment)