Purine itself is not common, but the purine structure is present in many natural substances.
This basic structure is present in essentially every normal human subject.
Blachon, S. et al. A proximal centriole-like structure is present in Drosophila spermatids and can serve as a model to study centriole duplication.
However, severed nerve cells on an amputated limb can only grow if a structure is present to support them much the way a trellis supports a growing vine.
Though a similar structure is present in mammals, the superior colliculus, scientists believe it plays a much smaller role (e.g. controlling head and eye movements).
Instead a capacitor-like structure is present with the potential decaying sinusoidally over the oscillatory ion arrangements.
The limiting behaviour in the terminal zone suggests that a lamellar structure is present in the melt.
"Hierarchical structure is present not only in single words, but also in compounds, which, contrary to the claims of some, are not the structureless fossilized form of a prior stage," Miyagawa says.
Given the equivocal result of the CFA, additional exploratory work is needed to determine if a more complex factor structure is present.
A completely different structure is present on the eastern slopes of the Drahany Uplands, especially when compared to the character of the Szeletian sites.
Immunoprecipitation studies indicate that a trimethylguanosine cap structure is present at the 5′ end and that the RNA is bound to core proteins common to spliceosomal ribonucleoprotein particles.
