Abstract: A 3D printing apparatus and method includes a piezo actuator that reciprocates a tappet. The reciprocation of the tappet generates pressure within a chamber filled with molten print material. The generated pressure causes the molten print material to be extruded through a nozzle coupled to the chamber. The piezo actuator is controlled to switchably provide continuous extrusion of print material or extrusion of discrete droplets of print material.

Abstract: Systems and methods of additively manufacturing leak resistant objects are disclosed. Provided herein are methods of forming objects having walls and/or surfaces that are resistant to leaks. Objects disclosed are formed from or manufactured from compositions, including metals, polymers, and combinations thereof. Objects provided herein are made from methods of forming individual shells, forming of series shells, and layer-by-layer forming of objects. Further disclosed are methods of interconnecting shells, layers, and processes for transitioning therebetween the shells and layers.

Abstract: Transesophageal echocardiographic probe having simultaneous cardiac pacing and echocardiographic capability. The inventive probe is provided with transducer means to provide echocardiographic imaging of the ventricular wall motion of a patient's heart as it is stress-paced by a novel pacing electrode connectable to the periphery of the transesophageal probe. By locating the pacing electrode upon the periphery of the probe a selected distance from the echo transducer, placement of the pacing electrode to produce optimal atrial pacing can be optimized. A method setting forth a diagnostic protocol to achieve echocardiographic diagnosis is also disclosed.