Abstract: Described herein are encapsulation devices that include an inner layer, an outer layer, a cell containment layer positioned between the inner and outer layer, and structural elements disposed within the cell containment layer to separate the inner and outer layers by a separation distance. The structural elements define reservoir spaces for the retention of a biological moiety (such as cells) therein. The structural elements maintain a separation distance both under external compressive forces and under internal expansive forces, such as undergoing a geometric change in the encapsulation device or during crushing and subsequent expansion of the cell encapsulation device. In some embodiments, a reinforcing layer is positioned between the inner layer and the cell containment layer. In addition, the encapsulation device may include at least one configuration element. Methods of placing encapsulation devices in a body conduit intra-luminally, extra-luminally, and via an open surgical procedure are also disclosed.

Abstract: An apparatus for providing ultrasonic energy for deposition in body tissue including an array of elements having at least two different sizes and at least one element being aperiodically spaced with the respect to other elements in the array. Excitation of the elements produces a beam of ultrasonic energy having reduced grating lobes. Reduced grating lobe magnitude permits improved ultrasonic beam focusing and/or the use of larger element sizes.

Abstract: A stent-graft which is particularly useful for applications in biliary ducts. An expandable stent is provided with a covering of a material which is substantially impervious to body fluids and tissue ingrowth and has an increased resistance to bacterial attachment due to its lack of porosity and reduced surface texture. A preferred covering is porous PTFE film rendered substantially non-porous by a coating of a polymeric material such as FEP. The resulting stent has a thin wall for minimum pre-deployment diameter and for minimum interference with fluid flow through the device after implantation. It has good flexibility, allowing its use in curved ducts.

Abstract: A removable device such as a stent-graft, intended for applications where it may be desirable to remove the device at some time following implantation. The stent-graft of the present invention includes a helically-wound stent component provided with a covering of graft material. It is removable by gripping an end of the helically-wound stent component with a retrieval device and applying tension to the stent component in the direction in which it is intended to be withdrawn from the site of implantation. The use of such a retrieval device allows the stent-graft to be removed remotely, such as via a catheter inserted into the body at a different location from the implantation site. The design of the stent-graft is such that the stent component is extended axially while the adjacent portion of the graft separates between windings of the stent component.

Abstract: An apparatus for providing ultrasonic energy for deposition in body tissue including an array of elements having at least two different sizes and at least one element being aperiodically spaced with the respect to other elements in the array. Excitation of the elements produces a beam of ultrasonic energy having reduced grating lobes. Reduced grating lobe magnitude permits improved ultrasonic beam focusing and/or the use of larger element sizes.