Hetero disperse

Various other investigators have isolated PAS-0 or fragments of this glycoprotein from either milk lipid globule membranes (Fischer et al. 1984) or human skim milk (Ormerod et al 1983). The preparation of Ormerod et al., called "epithelial membrane antigen," was hetero-disperse and appears to consist of proteolytic cleaved peptides of the... 

For a polymer dissolved in solvent, where the sample is typically hetero-disperse, the expression for the Rayleigh ratio is ... 

In solution, with increasing concentration c, surfactant association takes place. This happens suddenly or gradually, depending on the (homo- or hetero-) dispersity of the micelles to be formed. The difference between gradual and sudden is not sharp, and therefore it is debatable whether micelle formation may be considered a first-order phase transition. Automatically the question also arises whether at the interface association takes place if c is increased, and... 

The equations cannot be treated exactly like other orthokinetic equations because of the limitation i j. If i = j there would be no differential settlement and, therefore, no collisions and aggregation. Similarly, it cannot be applied to an initially monodisperse suspension because aU particles would settle at the same rate. If the suspension were subject initially to significant perikinetic (Brownian diffusion) flocculation then it would become hetero-disperse and flocculation by differential settling would follow. 

The presence in these copolymers of hetero-substituted monomeric units randomly dispersed along the phosphazene skeleton brings about the extreme difficulty of the polymeric chains to be packed in regular structures. They lose, therefore, the original stereo-regularity of the parent phosphazene homopolymers (microcrystalline materials), and show only amorphous structures, with sharp decrease in the values of the Tg (collapsed up to about -90 °C) and with the onset of remarkable elastomeric properties [399,409,457]. 

Fig. 17. Wavelength dispersion of refractive index of a hetero Y-type LB film consisting of C12PPy and arachidic acid.

Comparison of the Av values of diastereomeric complexes with 2-butanols, 2-pentanols, and 2-butylamines indicates that relative extent of electrostatic and dispersive forces depends upon the namre, the bulkyness, and the configuration of M. The A(Ar> ) = ((Ar )ijonjo — (Ai )i,etero) = +13 cm difference between the red shifts of the homochiral and the heterochiral complexes with 2-butanols finds a close analogy with LIF red-shift difference of the corresponding adducts with F/ = (/ )-(+)-2-naphthyl-l-ethanol (A(Ai ) = ((Aji)homo (AF)hetero)= +H cm Table 1). However, while LIF results from the diastereomeric [F/j M] (M = 2-pentanol) complexes are qualitatively similar to those with the other secondary... 

Cubic BC2N. Hetero-diamond B C—N compounds have recently received a great interest because of their possible applications as mechanical and optical devices. The similar properties and structures of carbon and boron nitrides (graphite and hexagonal BN, diamond, and cubic BN) suggested the possible synthesis of dense compounds with all the three elements. Such new materials are expected to combine the best properties of diamond (hardness) and of c-BN (thermal stability and chemical inertness). Several low-density hexagonal phases of B,C, and N have been synthesized [534] while with respect to the high-density phases, different authors report contradictory data [535-538], but the final products are probably solid mixtures of c-BN and dispersed diamonds [539]. 

The above description of the process is tentative because it is based on limited data. If it is correct, the predominate structures in the PHBA-modified products have amorphous PA/AA/NPG center sections end-capped with single units or short blocks of oligomeric PHBA. Random distribution of the PHBA cannot be ruled out, but the hetero-geneiety of the products suggests that a substantial fraction of PHBA is incorporated into short blocks. The FT-IR and GPC data are consistent with the proposal that short, phenolic-tipped oligomers are the predominant structure present. The possibility that the materials are physical mixtures of oligo-PHBA and amorphous diols can be virtually ruled out on the basis of the extreme insolubility of oligo-PHBA (IJ) and of the model PHBA-benzoic acid adduct synthesized in this study. These materials separate readily from solutions and dispersions of PHBA copolymers. 

HETCOR113 or hetero-TOCSY 114,115 see also a review by Pardi87 and references therein. Unfortunately, these methods are not routinely used for structure determination of nucleic acids, except for relatively short oligonucleotides, because of the relatively small chemical shift dispersion of 31P and its fast relaxation via the chemical shift anisotropy mechanism. 

These experiments clearly point to changes in local microenvironment, presumably ECM, as triggering crest cell dispersal in the axolotl, even though the molecules responsible are not known. Moreover, avian migratory stage crest cells do not migrate into early somitic tissue that is hetero-chronically transplanted, in contrast to their response to older somites (Bronner-Fraser and Stem,... 

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