However, as the study by Castilla and colleagues suggests that the rabbit PRNP gene and its normal PrPC protein product do not act as absolute barriers to TSE development after exposure to prions from other species, they also acknowledge that «what exactly makes the rabbit species comparatively resistant to prion disease remains to be clarified.» (sciencedaily.com)
Personalized learning gives girls the chance to try, to fail, and to shine without seeing roadblocks as absolute barriers. (nextgenlearning.org)
It poses an absolute barrier to natural reason; it brings all human undertakings to an end; it makes a mockery of artifice. (firstthings.com)