O Iversen’s research while affiliated with University of Oslo and other places

A pump which delivers from 0·01 to 0·65 ml fluid per beat at a frequency of 10-80 beats per min is described. Consecutive discharges agree within 1·5% of the average. Pumping is achieved by rhythmically compressing an elastic tube which has one-way valves at either end. Compression is achieved by oil pressure and controlled by an electronic regulator. This pump surpasses other micropumps with regard to precision, lack of hemolysis and versatility of capacity, frequency and pressure profile.

A method is described for measuring oxygen uptake of small aquatic animals using from 0.1 to 20 ml oxygen/hr. The water containing the animal is continuously equilibrated with air in a closed system and respiration is measured as the oxygen necessary to maintain a constant gas volume in the presence of a carbon dioxide absorber.