Table 1.

Mean cycles to failure and fold reduction between the control and irradiated groups

Stress level	Control		Irradiated		Fold reduction between control and irradiated groups
	Data	Mean ± SD	Data	Mean ± SD
25 MPa	2.58 × 107	**	1.14 × 107	(10.00 ± 10.8) × 106	57.7*
	3.07 × 107		1.29 × 107
	3.27 × 107		6.51 × 105
	3.12 × 107		3.25 × 104
	3.11 × 107		5.94 × 106
	3.05 × 107		2.91 × 107
35 MPa	1.18 × 107	(12.2 ± 12.3) × 106	5.39 × 105	(6.38 ± 6.81) × 105	19.1
	7.30 × 105		3.25 × 104
	2.60 × 106		1.90 × 106
	6.33 × 106		3.76 × 105
	1.75 × 107		1.47 × 105
	3.41 × 107		8.33 × 105
45 MPa	2.01 × 106	(7.31 ± 6.39) × 105	2.14 × 104	(4.17 ± 1.91) × 104	17.5
	3.56 × 105		5.76 × 104
	4.66 × 105		1.48 × 104
	5.44 × 105		5.48 × 104
	6.53 × 105		4.37 × 104
	3.52 × 105		5.79 × 104
55 MPa	5.02 × 104	(7.16 ± 2.86) × 104
	5.05 × 104
	1.02 × 105
	1.04 × 105
	5.14 × 104

** Five of six samples were run-outs in the control group, therefore, the mean and SD are not provided. As the 25 MPa control did not provide any mean, a higher stress level (55 MPa) test was performed for the control group only; *fold reduction at 25 MPa was calculated by estimating the mean cycles to failure of 25 MPa control by using the curve fit equation.