The present invention provides a compound of Formula I or a pharmaceutically acceptable derivative, salt or prodrug thereof. In another embodiment, a controller stores a message containing a directive in a memory shared by a processor of a computer system and the controller which may be operated independently of the state of said processor and said operating system. A shroud is positioned about the elongate structure for supporting engagement with the periphery of the passageway and to provide a space through which the elongate structure can move.