Developmental ability of mouse 8-cell embryos as a function of the cooling and warming rate after vitrification with 1.0× EAFS10/10. The cooling rates (°C/min) were 95 (□), 880 (■), or 69,000 (■), and the warming rates (°C/min) were 610, 4050, or 117,500. The protocols are given in Tables 2 and 3. Developmental ability is the percentage of “thawed” embryos that developed to blastocysts after 2 days incubation in M16 medium. Values with different superscripts were significantly different (P < 0.05) by one-way ANOVA or two-tailed t-tests. Different capital letters show statistically significant differences in developmental ability with various cooling rates and the same warming rate, and different lower case letters show the differences with same cooling rate and various warming rates.