There is disclosed a runner for a Francis-type hydraulic turbine where each runner blade has a outlet edge comprising a deflected edge portion. The platelet composition includes a preservation medium comprising plasma and a gel-forming material in a concentration relative to the plasma such that the medium is in a sufficiently fluent state at about 37 C. Other aspects are apparent from the description and claims. The above microlaser can be combined with voltage-controlled variable-focus output optics in order to control the peak power density of the laser pulses.