Pathway diversity reflects the variable order of formation of these peripheral elements, which radiate outward from the common nucleus.
The most common nuclei used are those that do not require exogenous label such as P, H, and Na which generate spectra from endogenous metabolites [ 71].
Since the proton (H) is the most common nucleus in biological systems, and also the most sensitive nucleus among all nuclear species, the majority of MRI experiments are carried out to measure the protons in water molecules.
After peak pruning, the false peaks are removed by cross-referencing, if the spectra, sharing some common nuclei, are available.
For resonance assignment, the peaks that share common nuclei, N and H, are first grouped into spin systems.
Finally, cross-referenced information between spectra that share common nuclei, such as N and H, is used to refine the peak lists.
This is, with increasing supercooling, from a morphology composed essentially of individual lamellae arranged in parallel stacks and radiating from common nuclei through coarse, somewhat branched microstructures whose parallel stacks diverge, to finer, more-branched pseudo-spherulitic textures.
Common nuclei such as Carbon 12 (C-12) and Oxygen 16 (O-16), having an even number of protons and neutrons, cannot be observed using NMR.
Inspection of all of the other biases shared between two or more accessions found strong, consistent directions of homoeologous expression bias suggesting that the bias has roots in the independent evolution of the two progenitor species prior to reuniting within the common tetraploid nucleus.
One could also consider here a generalized version of the Product principle (P.13ξ), asserting the conditional existence of a maximal common overlapper a common "nucleus", in the terminology of Leonard and Goodman (1940)—for any non-empty set of entities satisfying a suitable condition.
