Abstract: A fitness device includes two support frames mounted in a box, two driving motors mounted on the two support frames, a pull rope reel connected to the driving motors, a fitness pull rope wound around the pull rope reel and extending out of the box, and a control system for controlling the driving motors. The control system includes a main controller, a power module, a communication module connected to the main controller, a driving circuit and a sampling module electrically connected to the driving motors and the main controller. The power module is electrically connected to the main controller and the communication module. The driving circuit is electrically connected to the power module, the main controller and the driving motors. The two symmetrical driving motors are used to drive the pull rope reel to drive the fitness pull rope, such that shakes and vibrations generated during exercise can be offset.

Abstract: Provided are compounds that are suitable for cryopreservation of cells. The compounds are non-toxic, water soluble, and free of any organic solvents. The compounds have the following structure: Formula (I), where n is 1, 2, 3, or 4 and each R is independently H or Formula (II), where each R? is independently chosen from aliphatic groups, aryl groups, and amino acid groups and at least one R is not H and the asterisked carbon has R or S stereochemistry or a racemate thereof. Also provided are compositions and methods of using the compounds to cryopreserve cell populations.