Abstract: Combinations of oppositely poled piezoelectric shapes which, when electrically stimulated, effect increased linear or rotational displacement. In a typical arrangement a length of PVDF piezoelectric material poled in one direction is spatially separated from a second similarly shaped length of PVDF piezoelectric material poled in the opposite direction by an electrically inert substance. When stimulated by an appropriate voltage, one length contracts while the other length expands producing an increased deflection in the combination.

Abstract: Combinations of oppositely poled piezoelectric shapes which, when electrically stimulated, effect increased linear or rotational displacement. In a typical arrangement a length of PVDF piezoelectric material poled in one direction is spatially separated from a second similarly shaped length of PVDF piezolectric material poled in the opposite direction by an electrically inert substance. When stimulated by an appropriate voltage, one length contracts while the other length expands producing an increased deflection in the combination.

Abstract: A mechanical apparatus for suturing biological tissue, or ligating a biological tube or duct, in remote or otherwise inaccessible areas such as internal body cavities. The suturing apparatus includes an elongated housing, a head assembly pivotally mounted to the elongated housing capable of independent articulation, a continuous loop belt mounted within the elongated housing and head assembly for circulation therein, an arcuate needle mounted in the head for 360.degree. rotation having a plurality of projecting means for engaging the continuous loop belt, means for articulating the head assembly from a position outside a patient's body, and means for circulating the continuous loop drive belt. A kit for suturing biological tissue, or ligating a biological tube or duct, comprising a cannula and a mechanical apparatus for suturing or ligating as described above, configured and dimensioned to be slidingly received in the cannula.

Abstract: A mechanical apparatus for suturing biological tissue including a cassette housing, a continuous loop belt mounted for circulation therein, an arcuate needle mounted within the cassette for 360.degree. rotation having a plurality of closely spaced projecting means for engaging the continuous loop belt, and means for circulating the continuous loop belt. The cassette housing is easily attachable to and detachable from the means for circulating the continuous loop belt.

Abstract: A TROCAR catheter assembly employs a regulated gas flow between a catheter and the inner wall of a cannula sleeve in which the catheter moves. Annular grooves are formed in the wall of the sleeve and the grooves are connected to a source of gas which produces a pressure differential which causes gas to flow in a manner to control passage of gas to or from a body cavity in which the sleeve is inserted. In one embodiment, one of the annular grooves is connected to a bladder which is inflated to seal the entire opening defined by the inner wall of the sleeve when the catheter is absent.