Mosaic structures

If an ideal solution is formed, then the actual molecular A is just Aav (and Aex = 0). The same result obtains if the components are completely immiscible as illustrated in Fig. IV-21 for a mixture of arachidic acid and a merocyanine dye [116]. These systems are usually distinguished through the mosaic structure seen in microscopic evaluation. 

For density values g > 0.92 g/cm3 the deformation modes of the crystals predominate. The hard elements are the lamellae. The mechanical properties are primarily determined by the large anisotropy of molecular forces. The mosaic structure of blocks introduces a specific weakness element which permits chain slip to proceed faster at the block boundaries than inside the blocks. The weakest element of the solid is the surface layer between adjacent lamellae, containing chain folds, free chain ends, tie molecules, etc. 

Cell membranes consist of two layers of oriented lipid molecules (lipid bilayer membranes). The molecules of these two layers have their hydrocarbon tails toward each other, while the hydrophilic heads are outside (Fig. 30.1a). The mean distance between lipid heads is 5 to 6mn. Various protein molecules having a size commensurate with layer thickness float in the lipid layer. Part of the protein molecules are located on the surface of the lipid layer others thread through the layer (Fig. 30.1fc). Thus, the membrane as a whole is heterogeneous and has a mosaic structure. 

Gryns (1896), Hedin (1897), and especially Overton (1900) looked at the permeability of a wide range of different compounds, particularly non-electrolytes, and showed that rates of penetration of solutes into erythrocytes increased with their lipid solubility. Overton correlated the rate of penetration of the solute with its partition coefficient between water and olive oil, which he took as a model for membrane composition. Some water-soluble molecules, particularly urea, entered erythrocytes faster than could be attributed to their lipid solubility—observations leading to the concept of pores, or discontinuities in the membrane which allowed water-soluble molecules to penetrate. The need to postulate the existence of pores offered the first hint of a mosaic structure for the membrane. Jacobs (1932) and Huber and Orskov (1933) put results from the early permeability studies onto a quantitative basis and concluded molecular size was a factor in the rate of solute translocation. 

Watari, F. Delavignette, P. Van Landuyt, J. Amelinckx, S. (1979) Electron microscopic study of dehydration transformations. I. Twin formation and mosaic structure in hematite derived from goefhite. J. Solid State Chem. 

Welch, R.A. Burland, V. Plunkett, G. Redford, P. et al. Extensive mosaic structure revealed by the complete genome sequence of uropathogenic Escherichia coli. Proc. Natl. Acad. Sci. USA, 99, 17010-17014 (1001)... 

These requirements would be fulfilled if SDS were bound to the BSA monolayer in the form of small aggregates or pseudo-micelles. Such aggregates have been demonstrated to be formed as the result of the interaction of SDS and BSA in solution (2). Further, the electrostatic nature of the interaction was demonstrated by the fact that the complex was completely dissociated by adjusting pH to values above 10.0. Therefore, it is suggested that the cause of the marked shift in pK of the ammonium groups of the SDS-BSA surface complex was the presence of aggregates of SDS bound at cationic sites of the protein monolayer. It may be inferred from this hypothesis that the natural result of the interaction of anionic lipids with an interfacial protein film is the formation of a mosaic structure—one of the proposed characteristics of biological membranes. 

The microscopic image shows a juxtaposition of differently orientated areas whose sizes, varying between a few microns and several tens of microns, are associated particularly with the elementary composition of the initial carbonaceous material (4, 18, 19). The formation of a texture of this type, often called a mosaic structure, can be compared (20) to the crystallization of a supersaturated solution areas, each characterized by a definite orientation, develop from nuclei up to the total consumption of the isotropic material surrounding them. 

Recent work in this Division has shown that various substances other than vitrinites, such as pitches from coal tars and petroleum tars, polyvinyl chloride, and polynuclear hydrocarbons, develop similar mosaic structures on heating. In fact this effect occurs with most high carbon materials which pass through a plastic stage during carbonization. 

Figure 1. Naphthaeene carbon-mosaic structure in semicoke. X 189...

Each sphere has a lamellar structure and a single preferred orientation but shows systematic variations in the optical extinction patterns, which indicate some variation from a strictly lamellar arrangement this is most noticeable at the poles of spheres. As they grow and meet obstructions to their enlargement in particular directions, their extinction behavior becomes increasingly complex, especially when the pitch nears solidification and the complete mosaic structure is formed. 

As early as 1829, the observation of grain boundaries was reported. But it was more than one hundred years later that the structure of dislocations in crystals was understood. Early ideas on strain-figures that move in elastic bodies date back to the turn of this century. Although the mathematical theory of dislocations in an elastic continuum was summarized by [V. Volterra (1907)], it did not really influence the theory of crystal plasticity. X-ray intensity measurements [C.G. Darwin (1914)] with single crystals indicated their mosaic structure (j.e., subgrain boundaries) formed by dislocation arrays. Prandtl, Masing, and Polanyi, and in particular [U. Dehlinger (1929)] came close to the modern concept of line imperfections, which can move in a crystal lattice and induce plastic deformation. 

Comprehensive investigations into brittleness of some crystals determined with a Vickers pyramid led Ikornikova and Khrenova (1951) to establish that crystals of mosaic structure with traces of plastic deformation are more brittle than similar crystals of homogeneous structure. Moreover it has been found (Glazov and Vigdorovich, 1969) that as the mean square displacement of the lattice structural components diminishes, in other words, as the mobility of these components diminishes with propagation of elastic waves, the ultimate effect is increased material brittleness. 

The social matrix within which any emergent tool inhere will determine the nature of its use. Much more important however, in terms of long-range prediction, is the means by which the information about the tool is transferred. The mechanical process that breaks down a total situation into discrete units allows for a slow dissemination of partial product along a linear chain, unlike an electrical network, which provides for instantaneous transmission of information within mosaic structure whose extent is limitless. 

These antipodes reflect the extremes of a battle between linear and mosaic structures, both of which will be totally destructive of all that we hold to be human. In the center, attempting to hold these incongruities together, is the schizophrenic, an adequate reflection of the fragmented world in which he is forced to live linear parents and teachers, mosaic media. 

The global water balance consists of the mosaic structure of local balances at the level of Qy. The proposed description of water fluxes enables us to trace their balance at any level of spatial digitization region, water basin, continent, ocean, hemisphere, or biosphere. Clearly, the general balance of evaporation and precipitation at the level of the biosphere is maintained. In other cases, as the spatial size of the... 

S. Limulus Factor C endotoxin-sensitive serine protease zymogen with a mosaic structure of complement-like, epidermal growth factor-like and lectin-like domains. J Biol Chem 266... 

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