STS-79 mission specialists Carl Walz (left) and Jay Apt (right), both wearing surgical gloves and masks, prepare to work with the Biotechnology System (BTS) experiment housed on the Atlantis's middeck in locker MA16F (004-9). Apt injects a sample into a sample holder with Wales's help (010-11). View 011 is underexposed. Walz and Apt review procedures for the experiment (012).