A method and apparatus for selectively masking off unknown captured scan data in first selected scan cells 220 from propagating through the scan chains 221 for test, debug, diagnosis, and yield improvement of a scan-based integrated circuit 207 in a selected scan-test mode 232 or selected self-test mode. A dynamic credit limit may be associated with a counterparty or a debt security of the counterparty, for example. A transimpedance amplifier is connected to the input transistor. If the receiving target is within the predetermined proximity of the intended target, a reply is transmitted to the portable device to initiate handshaking. In another embodiment, a vapor conduit inside the accumulator for conveying refrigerant to an outlet port has an open vapor inlet end with chamfered cut edges pointing away from the inlet port to avoid liquid from splashing into the vapor conduit. Hand switches are placed in the range of the natural swing of the surgeon’s thumb, whether gripping the surgical instrument right-handed or left handed.