To each pellet, 7.5 g of 0.4–0.6 mm zirconium oxide grinding media (Glenn Mills Inc., Clifton, NJ)
was added, and the total aqueous volume was adjusted to 10 ml with
H2O. Samples were homogenized at a speed of 6.5 M/s for 60 s in a
FastPrep-24 instrument (MP Biomedicals, Santa Ana, CA).