Aggregation phenomena systems

There is a considerable body of literature describing the association (aggregation) phenomenon in specific systems and under specific conditions. Actually, this material concerns the morphological aspect only. None of the autliors has put a question as to the thermodynamic stimulus of association as correlated with a certain coiifigurative point on a certain state diagram. 

Incidentally, as is well known, in the unvulcanized state of the filled mbber, the stress upturn does not appear even in the carbon content of = 0.2-0.25. For understanding this phenomenon, we must consider the discontinuity between the SH layers, in addition to the very low modulus of the unvulcanized mbber. Actually, as we discussed earlier, carbon blacks disperse as an aggregate of carbon particles, then the continuity of carbon gels consisting of aggregates must be much poorer than the theoretical calculation based on the perfect dispersion of carbon particles. In this case, the stress cannot be transmitted from carbon gel to carbon gel through such a very soft medium, and as a result, the stress-strain curve of the system is rather similar to the characteristics of the... 

Practical metal catalysts frequently consist of small metal particles on an oxide support. Suitable model systems can be prepared by growing small metal aggregates onto single crystal oxide films, a technique whereby the role of the particle size or of the support material may be studied. [37] A quite remarkable example of the variation of the catalytic activity with particle size has recently been found for finely dispersed Au on a Ti02 support, which was revealed to be highly reactive for combustion reactions. [38] On the basis of STM experiments it was concluded that this phenomenon has to be attributed to a quantum size effect determined by the thickness of the gold layers. 

The intracellular deposition of ABP as the first pathogenic event prior to the appearance of tau pathology in AD (272) is an indirect evidence of ABP aggregation and incapacity of the ubiquitin-proteasome-chaperone system to repair the distorted metabolism of APP-ABP leading to neurodegeneration. A similar phenomenon with aggregation of conformation-abnormal peptides probably plays a key role in many other neurodegenerative disorders. 

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