A draping system for use in medical procedures includes a drape portion adapted to cover a surface, such as medical equipment or a patient, and serves as a barrier to fluid and debris during medical procedures. The apparatus comprises an optical path-length changing plate and an image sensor. Parts of the coil are buried in the grooves such that a distance between the outer surface of the coil wound on the core and the inner surface of the heating roller is constant. When the first participant is a special-purpose automated participant: the request includes an operation to be performed on the conversation; the operation is performed on the conversation at the server system; and the set of edits updates the conversation, in accordance with the operation. A media player application identifies media data on the portable media device that has been modified since a last synchronization process, and automatically or selectively retrieves the modified andor unmodified media data from the portable media device for storage on the client computer. On its circumferential surface, the nozzle body has means for engagement of a centering tool.