Clustering effect

Ligand activation and transformation at heterometallic clusters have been reviewed, but few examples of very mixed -metal clusters effecting these... 

CaineUi, G. Galletti, P. Giacomini, D. Gualandi, A. Quintavalla, A. Helv. Chim. Acta 2003, 86, 3548-3559. Variable-temperature C NMR experiments show that the solute-solvent clustering effect manages the chemical and enzymatic enantioselectivity. 

Results on Raman spectroscopy thus show that nitrogen incorporation, at least for a large enough N content, results in the increase of the graphitic clusters. This is contrary to the formation of an amorphous solid related to the -C3N4 phase, which presumes sp -C hybridization and no clustering effects. 

With respect to cluster seeking performance, RBFNs are influenced heavily by the occurrences of input data patterns because clustering effectively is averaged over individual pattern occurrences. It has been shown that this decreases the utility for interpretation (Kavuri and Venkatasubra-manian, 1993). Current approaches also require a priori specification of the number of clusters, a drawback from an adaptation standpoint. 

To better understand the critical role of oligosaccharide-receptor interactions and their molecular mechanisms through the cluster-effect, and thus access optimized synthetic ligands, several research groups have shown creativity in proposing original multivalent platforms that could allow for tailored valencies, dimensions, and epitope orientations. 

S. Fortier, M. Touaibia, S. Lord-Dufour, J. Galipeau, R. Roy, and B. Annabi, Tetra- and hexavalent mannosides inhibit the pro-apoptotic, antiproliferative and cell surface clustering effects of concanavalin A Impact on MT1-MMP functions in marrow-derived mesenchymal stromal cells, Glycobiology, 18 (2008) 195-204. 

Feller, A., Claeys, M., and van Steen, E. 1999. Cobalt cluster effects in zirconium promoted Co/Si02 Fischer-Tropsch catalysts. J. Catal. 185 120-30. 

O Brien, T. J., and Syamlal, M Particle cluster effects in the numerical simulation of a circulating fluidized bed, in (A. Avidan, Ed.) Circulating Fluidized Bed Technology IV, Proceedings of the Fourth International Conference on Circulating Fluidized Beds, Hidden Valley Conference Center and Mountain Resort, August 1-5, 1993, Somerset, PA, (1993). 

In the case of polynuclear metal cluster SCO complexes in the solid state, there will be intra-cluster, as well as inter-cluster cooperativity. To eliminate inter-cluster effects totally, studies must be made in dilute solutions. Williams et al. have done just this for a dinuclear [Fe(II)2L3] helicate complex which does not contain a good superexchange pathway between the Fe(II) centre but, rather, three flexible bis-bidentate ligands. A very broad, two step, SCO was observed (LS-LS<->LS-HS<->HS-HS) and fitted to a model for negative cooperativity in which subtle structural changes around each Fe oc-... 

Often a chemical being tested is both toxic as weft as potentially carcinogenic. When competing toxicity causes extreme differences in mortality or there is clustering effect in tumor prevalence in a very short interval of time, none of the adjusted methods works. One then must use biological intuition to evaluate the tumor data. 

Detailed theoretical studies have been made for the 5ivr2 reaction of methyl bromide with Me2CuLi.LiCl, with particular attention to solvent and cluster effects. ... 

If supramolecular assemblies of amphiphilic carbohydrates can display cluster effects, the specific binding of the latter are also dependent on the presentation of the carbohydrate to the receptor, i.e. its orientation and conformation. 

Several evidences, reported in the literature and briefly reviewed in the present article, demonstrate that the carbohydrate recognition at the surface of organized systems is somewhat different from that observed in isotropic media. These differences lie in (1) the conformation of carbohydrate which is affected by hydrophobization and by the nature of the surrounding lipids, (2) cluster effects from which can result in high energies of binding and which are affected by the fluidity of the lipid system, (3) entropy changes at the surface of a supra-molecular structure. 

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