In one embodiment, a computer program blocks windows categorized as bad windows, while allowing windows categorized as good windows to be displayed. Cleavage is at two sites: a typical cleavage site, Arg494-Val495, and a novel cleavage site, Arg424-His425. The surgical tool further includes an actuator configured to shorten a length of the wire to cause the movement of the surgical blade. Further, the lubricant is supplied to clearances formed between the first and second cover members and the first and second piston rods, thereby forming an oil film. The mounting flange is fastened to the ring.