An ultrasonically driven pump, which may be used for sampling body fluids or atomizing liquids, has a stationary outer needle and an inner needle mounted within the bore of the outer needle. The distal end of the inner needle is positioned adjacent to the distal end of the outer needle. The inner needle...http://www.google.com/patents/US20040204680?utm_source=gb-gplus-sharePatent US20040204680 - Ultrasonically actuated needle pump system
