Table 2.

Protocols for warming Cryotops from −196 °C at five different rates

Protocol No.	Insulation around Cryotop	Warmed by	Warming ratea± S.E. (°C/min)
1	Cryotop cap	Air at 23 °C	612±40 (N = 5)
2	Cryotop cap	Water at 23 °C	4,050±328 (N = 4)
3	None	Air at 23 °C	7,850±415 (N = 5)
4	None	Sucrose solutionb at 0 °C	24,000±5,843 (N = 5)
5	None	Sucrose solutionb 23 °C	117,500±10,632 (N =6)

^aThe warming rates were determined from ~ −170 to −30 °C by the instruments described by Kleinhans et al. [5]. N is the number of replicate runs.

^b2 ml of 0.5 M sucrose in PB1.