Arrays, ordered, compact

Any crystal of a globular protein can be regarded as an ordered and open array of compact molecules that make nearly minimal contact with... 

It is known from decades, particularly for Al, that porous oxide layers can be grown by anodization typically in acidic electrolytes, while anodization in neutral electrolytes typically leads to a compact oxide layer. However, Masuda et al were the first who showed that a very high degree of order can be achieved for these porous geometries. Zwilling et first reported the porous surface of titania films electrochemically formed in fluorinated electrolyte by titanium anodization, but only a decade later Grimes et al. showed that the nanostructure is constituted by uniform titania nanotube arrays. 

There is little doubt that many materials that at present are described as containing ordered arrays of point or extended defects will be successfully described as notionally defect-free modulated structures. For example, the intergrowth Aurivillius phases, described as containing extended planar defects, have recently been described compactly as modulated structures. " The same formalism has been applied to hexagonal perovskite structures and superconducting copper oxides. Others will certainly follow. 

Actin polymers form the thin filaments (also called microfilaments) in the cell that are organized into compact ordered bundles or loose network arrays by cross-linking proteins. Short actin filaments bind to the cross-linking protein spectrin to form the cortical actin skeleton network (see Fig. 10.6). In muscle cells, long actin fdaments combine with thick filaments, composed of the protein myosin, to produce muscle contraction. The assembly of G-actin subunits into polymers, bundling of fibers, and attachments of actin to spectrin and to the plasma membrane proteins and organelles, are mediated by a number of actin-binding proteins and G-proteins from the Rho family. 

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