Table 2.

Incidence of lung carcinoma and lung burden in rats exposed to MWNT-7 for 104 weeks

Concentration(mg/m3)	Lung carcinoma incidence (%)		Lung burden
			Amount of MWNT-7 (µg/g of bw)		Number of MWNT-7 (No/lung)
	Male	Female	Male	Female	Male	Female
Number of MWNT-7: 1µg=9.03×106 (calculated by SEM) Significant difference; *: p≦0.05 ** : p≦0.01 by Fisher Exact test
0	2	0	-	-	-	-
0.02	2	2	0.029±0.008	0.034±0.008	0.89×109	0.07×109
0.2	16*	0	0.434±0.056	0.453±0.056	1.38×109	1.07×109
2	22**	16**	4.954±0.420	4.712±0.201	16.2×109	10.8×109