Fig. 2

a, b Survival rates of rats exposed to MWNT-7 or clean air for 104 weeks. The survival rates of the rats are illustrated in panels A (male) and B (female). The survival rate exceeded 72 % in males and 68 % in females at the end of the 104 weeks experimental period. There were no differences in survival rates between the exposed and control groups. c, d Growth curves of rats exposed to MWNT-7 or clean air for 104 weeks. The growth curves of the rats are illustrated in panels c (male) and d (female). Body weights were measured once a week for the first 14 weeks and every 4 weeks thereafter. There was no growth retardation in any of the groups