The present invention relates to substituted dihydropyrimidine inhibitors of calcium channel function having formula Iwhere A, a, J, R1, R2 R3, R4, and R5, are defined herein; pharmaceutical compositions comprising said compounds; and methods of treating calcium channel-dependent disorders, including hypertension. The guidewire has a static central core and an imaging guidewire body comprising an acoustical scanning device. The reaction system is configured to retract the cutting tool at least partially away from the cutting region upon detection of a dangerous condition by the detection system. The first guide groove and the second guide groove are arranged at the side wall members of the housing, and guide the scanning carriage in a scanning direction.