Critical nucleus domain

The Grist dislocation model [98] assumes die formation in polymers crystalline regions of screw dislocation (or such dislocation pair) with Bulgers vector b and the yield process is realized at the formation of critical nucleus domain with size u ... 

The nucleus is assumed to have the same structure, density, etc. as the bulk phase, and have the same interaction energies with adjacent phases (surface tension, etc.). This conception has proved valuable in general, but a few of its assumptions are difficult to prove or incorrect on the molecular level (Talanquer and Oxtoby 1994). Other assumptions are practically impossible to test (ten Wolde and Frenkel 1997), as critical nucleus formation is a fleeting event that may not be amenable to any direct imaging method. However, as nanoparticles are of the same size domain as theoretical critical nuclei, an understanding of the nucleation process is essential to defining and possibly controlling the pathways for nanoparticle formation. 

Glutamine-rich transcription factor Spl is readily cross-linked by TG 2 (Han and Park, 2000). Inasmuch as some TG 2 is present in the nucleus, and Qn domains are excellent substrates, it is possible that TGs may modulate the activity of at least some transcription factors in vivo. Because TG activity is increased in HD brain, and because the expanded Qn domain of Htt is an excellent TG substrate, the possibility exists that TGs play a critical role in altered transcription level and properties in Q -expansion diseases. 

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