Below a melt temperature of 230 °C, the nucleation density was attributed to the seed nuclei, which result from incomplete melting of the spherulites.
Analyzed by energy-dispersive spectroscopy (EDS) measurement (see Additional file 1), most of these small particles were WO x S y grains, acting as seed nuclei and constantly reacting with S atoms to form WS2 flakes [21].
Micron sized metallic zinc dust (99.9%, Davg = 40 μm) was mechanically milled to have zinc oxide seed nuclei on its surface, eventually transforming it into ZnO nanostructures by microwave irradiation for 15 min.
Under pyrolytic or oxidative pyrolysis conditions at temperatures above approximately 600°C (zone 2), the metal seed nuclei promote reactions with gas-phase organic species to form a carbonaceous layer, resulting in nanoparticle growth (zones 2 and 3).
In practice sexual and apomictic plants are differentiated by i) cytological analyses of ovule development [ 23], ii) progeny tests using morphological or molecular markers [ 24], and iii) flow cytometry of seed nuclei to identify distinguishing embryo to endosperm ploidy level ratios [ 25].
The polymerization of many amyloids is a two-stage process initiated by the formation of a seeding nucleus or protofibril.
Freeze point is intrinsically a crystallisation phenomenon, in which the random presence of trace amounts of molecules and "seeding" nuclei may play an important role.
The amyloid formation process might be explained by a nucleation-dependent polymerization model (Fig. 1), in which there is a long lag phase during which seeds (nuclei) are formed (Jarrett and Lansbury 1993; Caughey et al. 2009; Aguzzi and Polymenidou 2004; Serio et al. 2000; Harper and Lansbury 1997).
These results indicate that aggregation occurs via an intermediate which behaves as a seed (or nucleus) for further aggregation.
The general strategy for segmentation has been to detect a distinct seed per nucleus [e.g. LoG, radial centroid transform, (IV)] that is followed through geometric partitioning.
As phosphorylation of Aβ promotes oligomer formation, phosphorylated Aβ oligomers could serve as seeds or nuclei that increase the rate of aggregation.
