A surgical instrument for both chopping and splitting the nucleus of an eye has a handle housing a shaft mounted within a guide tube which slides into and out of the instrument to bring first and second jaws into and out of contact with one another. Each of a plurality of interested entities may have its own password and each password may unlock a specific set of features offered by an integrated circuit. The slave circuit has a slave switch followed by a second inverter and a regenerative feedback-loop. Accordingly, it is possible to inhibit the air flow turbulence in the wake flow of the motor stay 9 from affecting the aerodynamic characteristics and noise characteristics of the axial flow impeller 7. which form hydrolyzable reaction products by a condensation reaction with the carbonyl compound used as the solvent, or a hydrolyzable reaction product of a diamine with a carbonyl compound. With the plunger in a third position, the single dose of medication is ejected from the delivery chamber though the injection port.