A two-dimensional photonic crystal coupler is disclosed, together with a cross-coupled laser structure that is based on a two-dimensional photonic crystal coupler stage. A plurality of struts are disposed to be stationary between a front impeller and a rear impeller in an air channel. A cooling system can incorporate a cooling cycle that utilizes thermal energy storage and has two coolant loops. Portions of a cardiac harness can be connected to each other using a coupling mechanism such as, for example, a zip coupler. The first controller monitors control bits and implements a counter in its own control registers for determining the size of a field being used. A single abrasive wire, or multiple turns of wire stretched tightly between wire guides, is then contacted with the rotating holder to slice the workpieces.