carbon-13


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carbon-13 (13C)

a naturally occurring isotope of carbon, with an atomic mass of 13, occurring 1.11% of the time. It is used as a tracer in liver function tests and a few metabolic tests.
References in periodicals archive ?
That is, Mars's atmosphere in this era, a period of great bombardment, had much less carbon-13 than it does today.
Any organisms using the carbon-13 labeled molecules would incorporate some of it into their RNA, he reasoned.
SAM's mass spectrometer and tunable laser spectrometer independently measured virtually identical ratios of carbon-13 to carbon-12.
Mahieu N, Powlson DS, Randall EW (1999) Statistical analysis of published carbon-13 CPMAS NMR spectra of soil organic matter.
Biases in carbon-13 and oxygen-18 measurements were decreased by up to a factor of five, which enabled up to a 50 % reduction in the uncertainty of reference material value assignments.
Ian Spenser and his group at McMaster University in Hamilton, ON have been studying the mechanism of biosynthesis by doping the food the organisms eat, not with steroids, but with Carbon-13.
The technology developed by Martek involves the placement of deuterium, carbon-13 and nitrogen-15 labeled isotopes into each amino acid backbone.
For example, methane derived from bacterial emissions such as from animals, rice paddies and wetlands contains lower levels of carbon-13 than methane derived from the burning of biomass or fossil fuels.
They are looking for ways to improve crop yield, quality and consistency, using a range of research methods including carbon-13 labeling to study the algal metabolism.
1 percent as carbon-13 and one part in 1,000,000,000,000 as carbon-14 for modern materials.
The team used a technique called Nuclear Magnetic Resonance spectroscopy (NMR) that can read the magnetic nuclei found in certain isotopes, such as carbon-13 -- which has one neutron more than most carbon.
Among the topics are the physical basis of the NMR experiment, proton chemical shifts and spin-spin coupling constants as functions of structure, the influence of molecular symmetry and chirality on proton magnetic resonance spectra, carbon-13 NMR spectroscopy, selected heteronuclei, and NMR of partially oriented molecules and solid-state NMR.