heavy isotope

heavy isotope

a stable atom in which there are more neutrons than in the normal isotope of the element, giving it a greater mass. For example, 15N is the heavy isotope, 14N the common form.
References in periodicals archive ?
The results are expressed using the I' notation in per mil (adeg) as I'13C = (Rsample:Rstandard - 1) x 1000, where R = 13C:12C and higher I' values denote a greater proportion of the heavy isotope. The international standard is Vienna Pee Dee Belemnite (VPDB).
Fitch et al., "Evaluation of in vivo T cell kinetics: use of heavy isotope labelling in type I diabetes," Clinical and Experimental Immunology, vol.
Previous spectrometer devices lacked the sensitivity to detect this heavy isotope in the atmosphere.
To produce good-quality weapons-grade plutonium--with a concentration of the most-important heavy isotope (Pu240)--a short "burnup" fuel cycle is employed, meaning that the reactor fuel rods are removed earlier than they would be if the reactor was utilized to produce electricity.
The probable age range of these fish suggests that an ontogenetic diet shift associated with maturation is difficult to extrapolate from these data because the trend of increasing heavy isotope values is confounded by changes in prey availability, by increases in fish prey capture efficiency with seatrout size, and by the potential variability of carbon and nitrogen sources within the Mississippi Sound and its subestuaries.
Tritium is a heavy isotope of hydrogen but it decays radioactively at the rate of 5.5 percent each year and must be replenished periodically.
Therefore in each case we have two possibilities, either muon can escape and proton is captured by heavy isotope to form a Helium ion or a mu-helium ion is formed.
With triple-stage validation (both mass spec & HPLC) and over 10 years of successful synthesis, ClearPoint[TM] peptides are the proven solution for optimum quality heavy isotope labeled peptides.
childressi and platyhelmenthies were depleted in [sup.13]C and [sup.15]N relative to other fauna, possibly because of very close proximity to the sediment water interface, where transformations of C[H.sub.4] and N[H.sub.3] were presumably rapid, resulting in discrimination against the heavy isotope in those species.
Distinct heavy isotope ratios characterize all three sites and show regional differentiation broadly consistent with geological expectations.
where i is the heavy isotope of the element and E represents the element of interest (carbon, nitrogen, or sulfur).
As an example, a sulfur crystal growing from a fluid will incorporate preferentially the heavier isotope, so that the crystals are enriched in the heavy isotope compared to the liquid, albeit only by a few tenths of a percent (Kyser, 1987).