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Absorption half-life 1 h, elimination half-life 12 h. Biological half-life (elimination half-life, pharmacological half-life) is the time taken for concentration of a biological substance (such as a medication) to decrease from its maximum concentration (C max) to half of C max in the blood plasma.
For example, the medical sciences refer to the biological half-life of drugs and other chemicals in the human body. The converse of half-life (in exponential growth) is doubling time. The original term, half-life period, dating to Ernest Rutherford's discovery of the principle in 1907, was shortened to half-life in the early 1950s. [1]
Radioactive isotope table "lists ALL radioactive nuclei with a half-life greater than 1000 years", incorporated in the list above. The NUBASE2020 evaluation of nuclear physics properties F.G. Kondev et al. 2021 Chinese Phys. C 45 030001. The PDF of this article lists the half-lives of all known radioactives nuclides.
The half-life of phosphorus-32 is 14.2 days, and its maximum specific activity is 9,131 kCi/mol (337.8 PBq/mol). Phosphorus-33 is used to label nucleotides. It is less energetic than phosphorus-32 and does not require protection with plexiglass .
Thus, the longer the biological half-life of a toxic substance, the greater the risk of chronic poisoning, even if environmental levels of the toxin are not very high. [2] Bioaccumulation, for example in fish, can be predicted by models.
Has no known biological role; as it is radioactive with a short half-life, it is very rare and is seldom present for long. [11] Radioactive. [11] protactinium: 91: 1b: Has no known biological role; as it is radioactive with a short half-life, it is very rare and is seldom present for long. [11] Both toxic and highly radioactive. radium: 88: 1bc
The biological half life of tritiated water in the human body, which is a measure of body water turn-over, varies with the season. Studies on the biological half life of occupational radiation workers for free water tritium in a coastal region of Karnataka , India, show that the biological half life in the winter season is twice that of the ...
Naturally occurring strontium is nonradioactive and nontoxic at levels normally found in the environment, but 90 Sr is a radiation hazard. [4] 90 Sr undergoes β − decay with a half-life of 28.79 years and a decay energy of 0.546 MeV distributed to an electron, an antineutrino, and the yttrium isotope 90 Y, which in turn undergoes β − decay with a half-life of 64 hours and a decay energy ...