{TAIL ~ A user programmable control mechanism} is coupled to the drug pump and is effective to selectively control {HEAD ~ movement} of the valves between the open and closed positions 
{ TAIL ~ A user programmable control mechanism } is coupled to the drug pump and is effective to selectively control { HEAD ~ movement } of the valves between the open and closed positions
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH