The present invention provides for triazolopurine-based tricyclic compounds having the formula ,wherein R1, R2, R3, R4, and R5 are as described herein. The article includes an absorbent chassis, a barrier sheet and a leak-barrier cuffs. The cooling is performed by contacting the hot gas with the coolant so as to provide a temperature of a wall of the gas supply tube at least 50\xb0 C. A release mechanism attached between ends of the tow line engages a stop on the retraction tower and automatically releases the ride vehicle into a pendulum motion. The gear reducer includes a drive shaft that connects with a drive coupling. Further, a detector housing is disclosed, which has the housing wall, for an X-ray computed-tomography scanner.