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[1] [2] 129 Xe is a stable, naturally occurring isotope of xenon with 26.44% isotope abundance. It is one of two Xe isotopes, along with 131 Xe, that has non-zero spin, which allows for magnetic resonance. 129 Xe is used for MRI because its large electron cloud permits hyperpolarization and a wide range of chemical shifts
In terms of detecting ventilation defects, 129 Xe has a lower signal-to-noise ratio but is more sensitive to defects due to its higher density and lower diffusivity. [30] Currently, using a larger volume of 129 Xe (up to 1 liter per scan) can compensate for its decreased signal-to-noise ratio compared to 3He (usually 0.1-0.3 liters per scan).
Naturally occurring xenon (54 Xe) consists of seven stable isotopes and two very long-lived isotopes. Double electron capture has been observed in 124 Xe (half-life 1.8 ± 0.5(stat) ± 0.1(sys) × 10 22 years) [2] and double beta decay in 136 Xe (half-life 2.165 ± 0.016(stat) ± 0.059(sys) × 10 21 years), [7] which are among the longest measured half-lives of all nuclides.
The first explicit recognition of non-atmospheric Xe in terrestrial samples came from the analysis of CO 2-well gas in New Mexico, displaying an excess of 129 I-derived or primitive source 129 Xe and high content in 131-136 Xe due to the decay of 238 U. [38] At present, the excess of 129 Xe and 131-136 Xe has been widely observed in mid-ocean ...
In a similar way, xenon isotopic ratios such as 129 Xe/ 130 Xe and 136 Xe/ 130 Xe are a powerful tool for understanding planetary differentiation and early outgassing. [28] For example, the atmosphere of Mars shows a xenon abundance similar to that of Earth (0.08 parts per million [97]) but Mars shows a greater abundance of 129 Xe than the ...
Biosensors used for screening combinatorial DNA libraries. In a biosensor, the bioreceptor is designed to interact with the specific analyte of interest to produce an effect measurable by the transducer. High selectivity for the analyte among a matrix of other chemical or biological components is a key requirement of the bioreceptor.
The xenon atom trapped in the fullerene can be observed by 129 Xe nuclear magnetic resonance (NMR) spectroscopy. Through the sensitive chemical shift of the xenon atom to its environment, chemical reactions on the fullerene molecule can be analyzed. These observations are not without caveat, however, because the xenon atom has an electronic ...
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