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Carbon-14, C-14, 14 C or radiocarbon, is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons.Its presence in organic matter is the basis of the radiocarbon dating method pioneered by Willard Libby and colleagues (1949) to date archaeological, geological and hydrogeological samples.
It is based on the fact that radiocarbon (14 C) is constantly being created in the Earth's atmosphere by the interaction of cosmic rays with atmospheric nitrogen. The resulting 14 C combines with atmospheric oxygen to form radioactive carbon dioxide, which is incorporated into plants by photosynthesis; animals then acquire 14 C by eating the ...
Carbon-14 labeling is common in drug development to do ADME (absorption, distribution, metabolism and excretion) studies in animal models and in human toxicology and clinical trials. Since tritium exchange may occur in some radiolabeled compounds, this does not happen with carbon-14 and may thus be preferred.
[citation needed] Silicon biochemistry (Organosilicon) Alternative biochemistry Silicon-based life Like carbon, silicon can create molecules that are sufficiently large to carry biological information; however, the scope of possible silicon chemistry is far more limited than that of carbon. [citation needed] Silicon dioxide biochemistry
Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is considered radioactive. Three of the most common types of decay are alpha, beta, and gamma decay.
Radioactive nonprimordial, but naturally occurring on Earth. 61 347 Carbon-14 (and other isotopes generated by cosmic rays) and daughters of radioactive primordial elements, such as radium, polonium, etc. 41 of these have a half life of greater than one hour. Radioactive synthetic half-life ≥ 1.0 hour). Includes most useful radiotracers. 662 989
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 composition of the human body can be classified as follows: Water; Proteins; Fats (or lipids) Hydroxyapatite in bones; Carbohydrates such as glycogen and glucose; DNA and RNA; Inorganic ions such as sodium, potassium, chloride, bicarbonate, phosphate; Gases mainly being oxygen, carbon dioxide; Many cofactors.