Half-life

Plutonium-244 has a half-life of 80 million years.

Plutonium-239 has a half-life of 24,100 years.

The Half-Life logo is actually a Greek letter known as the lambda.

Half-Life: Alyx is widely expected to be a killer app for VR.

"The guy that just left—what's he got in his lungs?" / "Well, I'm not very sure. But the two best candidates are uranium-233 and plutonium-239, one or both." / "They're in his bones too, aren't they?" / "Yeah, they're both boneseekers. And they've got half-lives of one hundred sixty-two thousand and twenty-four thousand years respectively. So they stay hot for a long time."

O₂^(•−) and OH^• are highly unstable (half-life at the level of microseconds and nanoseconds, respectively) and cannot cross membrane, while H₂O₂, though not a free radical but a ROS, is relatively stable (half-life around 1 ms) (Møller et al. 2007) and can cross membranes through aquaporins.

For nonporous surfaces such as steel, in a dark and low-humidity environment, the CCP virus has an 18-hour half-life—the time required for it to decrease by half , according to the researchers' findings.

Most books of scholarship have surprisingly short intellectual half-lives during which they make a difference"