9 SCIENTIFIC AND ELECTRICAL APPARATUS, NAMELY, HEAT EXCHANGE SYSTEMS FOR CATHETERS, HEAT EXCHANGE SYSTEMS FOR CATHETERS WITH HEAT EXCHANGE MEMBERS; HEAT EXCHANGE SYSTEMS FOR CATHETERS WITH FLUID-FILLED HEAT EXCHANGE MEMBERS, HEAT EXCHANGE SYSTEMS FOR BALLOON CATHETERS; TEMPERATURE CONTROL APPARATUS AND INSTRUMENTS, NAMELY, TEMPERATURE REGULATORS FOR CONTROLLING FLUID TEMPERATURES, TEMPERATURE REGULATORS FOR CONTROLLING THE TEMPERATURE OF FLUID-FILLED HEAT EXCHANGE MEMBERS, AND ELECTRONIC CIRCUITS FOR CONTROLLING FLUID TEMPERATURES