The pills only contain a very small amount of nitroglycerin diluted with inert material to make it safe.

这些药丸仅含有极少量用惰性材料稀释的硝酸甘油，以确保安全。

Crucially, in that gel were plenty of thioketals, compounds that fall apart when exposed to reactive, oxygen-containing molecules, plus just a sprinkle of titanium dioxide--an inert material that, when exposed to ultrasound, releases just those molecules.

至关重要的是，这种凝胶中含有大量的硫酮化合物，这种化合物接触到活性的含氧分子就会分解，外加少量二氧化钛--一种惰性物质，暴露在超声波下时，这些分子就会被释放。