Fig. 1.

(a) A schematic of a 6 ml vial designed to produce PS (progressive solidification). Heat is extracted only from the base of the vial (shown by the arrow) with no thermal transfer through the other edges, and so the sample progressively solidified upwards. Prior to thaw, the cells were removed from the vial and dissected into quintiles as shown to the right of the vial. (b) A schematic of the face of the BAL chamber is shown to the right. As this biomass is cooled from the edges, each semi-circle line represents equal cryopreservation conditions. The maximum biomass depth was 7 cm (from the number ‘5’ in the figure directly down).