Secondary aggregation

Gravel and crushed rock—stone chips— are obtained by quarrying. Some gravels are collected by sea dredging, which destroys marine environments. However, secondary aggregates, such as crushed rubble from demolition works, offer an alternative to newly quarried materials, and make an attractive, durable surface. 

Finally, freeze-dried, AmB-loaded PEBPBLA micelles easily dissolved within a few seconds in aqueous solutions. This contrasts with the behavior of PEKBbA and AmB, both of which are insoluble when directly placed in water. TEM reveals that the PtRBItA micelles remain intact, and the size distribution conLrms the absence of any secondary aggregation that may have resulted from the freeze-drying and reconstitution processes. Further, the resultant AmB-loaded PEO-bPBLA micelles cause no hemolysis atflQ/mL, indicating that AmB is still present inside the polymeric micelles. An AmB level of 5.0 mg/mL was obtained this is 10,000 times the solubility... 

The mildness of this defect is supported by the fact that very modest hemostatic defects are noted in patients with diseases involving deficiencies of platelet COX and thromboxane synthase—eg, these patients have no history of increased or decreased bleeding. Blockade of either of these two enzymes inhibits secondary aggregation of platelets induced by ADP, by low concentrations of thrombin and collagen, or by epinephrine. Thus, these platelet enzymes are not necessary for platelet function but may amplify an aggregating stimulus. 

Both of these effects refer to a high surface activity and specific surface of the filler particles [26, 27, 47]. In view of a deeper understanding of such structure-property relationships of filled rubbers it is useful to consider the morphological and energetic surface structure of carbon black particles as well as the primary and secondary aggregate structure in rubber more closely-... 

The density distribution function, gla (y), that accounts for the break-down of secondary aggregates attributed to non-linear rubber phase deformation. 

At the second and third stages, the processes involving plastic deformation of particles are developed. The smaller is particle size, the more efficient are these processes. Dispersion process is overlapped by the formation of secondary particles, while the rate of the latter process is comparable with dispersing rate thus, the surface area remains constant. Chemical reactions take place inside secondary aggregates at the contacts between particles. At the third stage, the crystallization of the products from the solid phase may occur, as well as its repeated amorphization, till some stationary state between these two is achieved. 

The rate of mechanochemical interaction is strongly affected by the particle size of initial components. Fine particles get in close contacts with each other secondary aggregated particles arise, their size being equal to 2-rlO im chemical interaction proceeds with higher efficiency inside these particles. 

Zucker MB, Peterson J.bihibiticm of adenosine diphosphate-mduced secondary aggregation and odier platelet functions by acetylsalricylic arid ingestkm. Proc Soc. Exp Biol Med 1968,127 547-551... 

HOLMSEN H, SeTKOWSKY CA, Day HJ. Effects of antimycin and 2-deoxygIucose on adenine nucleotides in human platelets. Role of metabolic adenosine trisphosphate in primary aggregation, secondary aggregation and shape change in platelets. BiodiemJ 44 385-396,1974. 

It is obvious that the higher the concentration of silica primary particles is the denser primary and secondary aggregations and heavier density of the hydro- and xerogels. 

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