Two men buried long ago in a medieval graveyard in Co. Donegal had a genetic condition called multiple osteochondromas, which causes benign bone tumors. One of the disease mutations is a new discovery, so this is the first ...
Dec 5, 2022
0
47
The liver is an essential organ that takes care of clearing toxins in our bodies. Because it constantly deals with toxic substances, it is likely to be regularly injured. To overcome this, the liver has a unique capacity ...
May 31, 2022
0
215
Leprosy is a bacterial infection caused by Mycobacterium leprae or Mycobacterium lepromatosis. It has afflicted humans for thousands of years, reaching epidemic levels during the Middle Ages, and people continue to be affected ...
Jan 26, 2017
0
20
Notorious among athletes and trainers as career killers, Achilles tendon injuries are among the most devastating. Now, by carbon testing tissues exposed to nuclear fallout in post WWII tests, scientists have learned why: ...
Feb 12, 2013
1
0
Carbon-14, 14C, or radiocarbon, is a radioactive isotope of carbon discovered on February 27, 1940, by Martin Kamen and Sam Ruben at the University of California Radiation Laboratory in Berkeley, though its existence had been suggested already in 1934 by Franz Kurie. Its nucleus contains 6 protons and 8 neutrons. Its presence in organic materials is the basis of the radiocarbon dating method to date archaeological, geological, and hydrogeological samples.
There are three naturally occurring isotopes of carbon on Earth: 99% of the carbon is carbon-12, 1% is carbon-13, and carbon-14 occurs in trace amounts, e.g. making up as much as 1 part per trillion (0.0000000001%) of the carbon in the atmosphere. The half-life of carbon-14 is 5,730±40 years. It decays into nitrogen-14 through beta decay. The activity of the modern radiocarbon standard is about 14 disintegrations per minute (dpm) per gram carbon.
The atomic mass of carbon-14 is about 14.003241 amu. The different isotopes of carbon do not differ appreciably in their chemical properties. This is used in chemical research in a technique called carbon labeling: some carbon-12 atoms of a given compound are replaced with carbon-14 atoms (or some carbon-13 atoms) in order to trace them along chemical reactions involving the given compound.
This text uses material from Wikipedia, licensed under CC BY-SA
