Spatial ordering

Most characteristics of amphiphilic systems are associated with the alteration of the interfacial stnicture by the amphiphile. Addition of amphiphiles might reduce the free-energy costs by a dramatic factor (up to 10 dyn cm in the oil/water/amphiphile mixture). Adding amphiphiles to a solution or a mixture often leads to the fomiation of a microenuilsion or spatially ordered phases. In many aspects these systems can be conceived as an assembly of internal interfaces. The interfaces might separate oil and water in a ternary mixture or they might be amphiphilic bilayers in... 

Thus, in contrast to what occurred in the jar, in an EPS the overall chemical reaction occurs in the form of two spatially separated partial electrochemical reactions. Electric current is generated because the random transfer of electrons is replaced by a spatially ordered overall process. 

Such integral depends only on the kind and on the amount of atoms present in every phase, and it is independent of their atomic spatial order, allowing it to be applied to both crystalline and amorphous materials [52]. 

Small angle X-ray-scattering studies and light-scattering studies of lens extracts show that the transparency of the lens is the result of the short-range spatial order of lens proteins (Delaye and Tardieu, 1983). The molecular structure of the individual crystallins is well ordered even though the overall pattern in the lens may appear chaotic. 

Structural chemistry or stereochemistry is the science of the structures of chemical compounds, the latter term being used mainly when the structures of molecules are concerned. Structural chemistry deals with the elucidation and description of the spatial order of atoms in a compound, with the explanation of the reasons that lead to this order, and with the properties resulting therefrom. It also includes the systematic ordering of the recognized structure types and the disclosure of relationships among them. 

In a crystal atoms are joined to form a larger network with a periodical order in three dimensions. The spatial order of the atoms is called the crystal structure. When we connect the periodically repeated atoms of one kind in three space directions to a three-dimensional grid, we obtain the crystal lattice. The crystal lattice represents a three-dimensional order of points all points of the lattice are completely equivalent and have the same surroundings. We can think of the crystal lattice as generated by periodically repeating a small parallelepiped in three dimensions without gaps (Fig. 2.4 parallelepiped = body limited by six faces that are parallel in pairs). The parallelepiped is called the unit cell. 

C. Bourdillon, C. Demaille, J. Moiroux, and J.M. Saveant, From homogeneous electroenzymatic kinetics to antigen-antibody construction and characterization of spatially ordered catalytic enzyme assemblies on electrodes. Acc. Chem. Res. 29, 529-535 (1996). 

An A-B diblock copolymer is a polymer consisting of a sequence of A-type monomers chemically joined to a sequence of B-type monomers. Even a small amount of incompatibility (difference in interactions) between monomers A and monomers B can induce phase transitions. However, A-homopolymer and B-homopolymer are chemically joined in a diblock therefore a system of diblocks cannot undergo a macroscopic phase separation. Instead a number of order-disorder phase transitions take place in the system between the isotropic phase and spatially ordered phases in which A-rich and B-rich domains, of the size of a diblock copolymer, are periodically arranged in lamellar, hexagonal, body-centered cubic (bcc), and the double gyroid structures. The covalent bond joining the blocks rests at the interface between A-rich and B-rich domains. 

Table 2 lists a number of publications of recent years on investigations of spatial orderings, interactions, and local structures, most of which have employed methods based on heteronuclear dipolar interactions. 

Visiers, I., Ballesteros, J. A., and Weinstein, H. (2000) A spatially ordered sequence of intramolecular rearrangements observed from simulations of agonist-related activation of 5HT(2C) receptors. Biophys. J. 78, 394. 

SPATIALLY ORDERED MULTIMONOMOLECULAR LAYERED ENZYME COATINGS... 

Already immobilized enzyme monolayers can be inactivated with iodoa-cetate, and active monolayers can be attached de novo on top of the inactivated layers. The use of these procedures allows the construction of a large variety of structures whose spatial order can be investigated as detailed in the next section. 

Reaction Dynamics with the Cosubstrate in Solution. Evidence for Spatial Order... 

Satisfactory agreement between the predictions of the diffusion-reaction model with the experimental data, particularly the ensuing estimate of a consistent interlayer distance, provides evidence of the spatial order resulting from the step-by-step construction of the multilayered coating. 

Still with an enzyme monolayer, the synthesis and current responses of a system that involves simultaneous attachment of the cosubstrate to the electrode coating are then described. The next step consists in constructing a multilayered coating constituted by successive layers of enzyme built thanks to antigen-antibody interactions. Sensing the diffusion of the cosubstrate through the film thus constructed provides evidence for spatial order and an estimate of the distances between layers. 

Fujii, M., Freude, W., and Russer, P., 2003, Efficient high-spatial-order FDTD analysis of 3D optical ring resonator filters, Proc. 19th Annual Rev. Progress in Appl. Comput. Electromagnetics, 739-744, Monterey, CA. 

The LbL methods have been also used to prepare spatially ordered bienzymatic electrodes, two examples are shown in Figure 2.25. In the first one, glucose is aerobically oxidized by GOx in the outer layers to produce hydrogen peroxide that is thereafter reduced by soybean peroxidase (SBP) wired to the electrode with PAH-Os [182]. This system responds both to H2O2 and to glucose, but in the... 

Figure 2.24 Diagrams of bienzymatic spatially ordered electrodes built using the LbL method. SBP Soybean peroxidase, COx Glucose oxidase, GDH glucose dehydrogenase.

When authors illustrate the subject of thermochemical conversion of solid fuels in the literature, the conversion zone in a packed bed is divided into different process zones (drying zone, pyrolysis zone, char combustion zone, and char gasification zone), one for each thermochemical conversion process. The spatial order of this process zones is herein referred to as the bed process structure or conversion process structure. The conversion process structure is a function of conversion concept. Even more important, the bed process structure can only exist in the diffusion controlled conversion regime when the conversion zone has a significant thickness. 

A.E. Gonzalez and G. Ramirez-Santiago Spatial Ordering and Structure Factor Scaling in the Simulations of Colloid Aggregation. Phys. Rev. Lett 74,1238 (1995). 

Figure 2.2 The spontaneous self-aggregation of membranogenic surfactants into a vesicle, with an interior water pool that can host water-soluble molecules. If this self-aggregation takes place also in the presence of hydrophobic molecules, and/or ionic molecules, these can organize themselves into the bilayer or on the surface of the vesicle. A realistic scenario of the emergence of life can be based on a gradual transition from random mixtures of simple organic molecules to spatially ordered assemblies, displaying primitive forms of cellular compartmentation, selfreproduction, and catalysis.

SPATIAL ORDER—telling how things are arranged in space (for example, top to bottom, bottom to top, near to far, inside out, and so on)... 

Raben, Remco 1996. Batavia and Colombo the Ethnic and Spatial Order of Two Colonial Cities, 1600-1800 . Ph.D. Dissertation, Leiden University. 

Last, but by no means least, reference should be made to the use of proteins in nano-fabrication [492]. One approach is illustrated by the fabrication of a 1-nm-thick metal film with 15-nm-diameters holes, periodically arranged on a triangular protein lattice [493]. Advantage was taken of the 10-nm-thick, uniformly porous surface (or S) layer of the crystalline protein obtained from the thermophilic bacterium Sulfolobus acidocaldarius. The protein was adsorbed from a dilute solution onto a molecularly smooth carbon-film surface, metal coated by evaporation, and ion milled to give spatial ordering of holes with the same nanometer periodicity as the protein lattice [493]. 

More recently a remarkably simple experimental example of spatial order in a one-variable system that presents an electrothermal instability has been analyzed by Bedaux et al.21... 

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