An air or gas bubble detection system detects the presence of liquid in intravenous tubing. Diffusion layers reside in upper portions of the pillar-shaped silicon layer and fin-shaped silicon layer and in a lower portion of the pillar-shaped silicon layer to form. 1bicyclo nucleosides which is shorter and provides higher overall yields proceeds via the key intermediate of the general formula III, wherein R4 and R5 are, for instance, sulfonates and R7 is, for instance, a halogen or an acetate. The interconnect includes interconnect contacts configured for bonding to, and then separation from component contacts on the components. The print head is variably loadable to a media-specific load. The preferred embodiments also include a wall system with various different blocks that may be used to build a wall.