Polarized structure functions

The taste bud is a polarized structure with a narrow apical opening, termed the taste pore, and basolateral synapses with afferent nerve fibers. Solutes in the oral cavity make contact with the apical membranes of the TRCs via the taste pore. There is a significant amount of lateral connectedness between taste cells within a bud both electrical synapses between TRCs and chemical synapses between TRCs and Merkel-like basal cells have been demonstrated to occur [39]. Furthermore, there are symmetrical synapses between TRCs and Merkel-like basal cells [39]. In addition, these basal cells synapse with the afferent nerve fiber, suggesting that they may function in effect as interneurons [39]. The extensive lateral interconnections... 

The hydrothermal carbons obtained in the end from soluble, non-structural carbohydrates are micrometer sized, spherically shaped particle dispersions, containing a sp2 hybridized backbone (also responsible for the brown to black color) decorated with a dense layer of polar oxygenated functionalities still remaining from the original carbohydrate. The presence of these surface groups offers the possibility of further functionalization and makes the materials more hydrophilic and well-dispersible in water. The size of the final particles depends mainly on the carbonization time and precursor concentration inside the autoclave, as well as additives and stabilizers potentially added to the primary reaction recipe. An SEM image of a model reaction illustrating this dispersion state is shown in Fig. 7.1. 

Complementary to using repulsive interactions in order to achieve shape control, attractive interactions of relatively large building blocks, which are rationally designed regarding their shape, polarity, and functional groups, can be employed for intramolecular self-assembly [23]. In this case, the molecular structure optimizes itself to realize specific interactions between the blocks and minimize the interfacial energy. 

According to this method, Fyles analyzed the transport rate of alkali metal cations for a series of 21 synthetic transporters (Figure 14). The whole molecules were designed to elucidate the structure-function relationship. They are composed of three parts core, wall, and head units. The core units were derived from tartaric acids so that the wall units may be fixed to provide structural control by incorporating both the polar and nonpolar functionality (Y and Z in Figure 14). The head groups (X) are attached to provide an overall amphiphilic nature. 

The affinity of the polymer-bound catalyst for water and for organic solvent also depends upon the structure of the polymer backbone. Polystyrene is nonpolar and attracts good organic solvents, but without ionic, polyether, or other polar sites, it is completely inactive for catalysis of nucleophilic reactions. The polar sites are necessary to attract reactive anions. If the polymer is hydrophilic, as a dextran, its surface must be made less polar by functionalization with lipophilic groups to permit catalytic activity for most nucleophilic displacement reactions. The % RS and the chemical nature of the polymer backbone affect the hydrophilic/lipophilic balance. The polymer must be able to attract both the reactive anion and the organic substrate into its matrix to catalyze reactions between the two mutually insoluble species. Most polymer-supported phase transfer catalysts are used under conditions where both intrinsic reactivity and intraparticle diffusion affect the observed rates of reaction. The structural variables in the catalyst which control the hydrophilic/lipophilic balance affect both activity and diffusion, and it is often not possible to distinguish clearly between these rate limiting phenomena by variation of active site structure, polymer backbone structure, or % RS. 

Radiative corrections to the nuclear polarizability a(Za) m to S -levels are described by the diagrams in Fig. 7.16 and in Fig. 7.17 (compare with the diagrams in Fig. 6.4). As usual for muonic hydrogen the dominant polarization operator contribution is connected with the electron loops, while heavier loops are additionally suppressed. The contribution of the diagrams in Fig. 7.16 was calculated in [52] on the basis of the experimental data on the proton structure functions... 

The structure functions G and G2 may be measured in inelastic scattering of polarized electrons on polarized protons. The difference between the spin antiparallel and spin parallel cross sections has the form... 

End view of energy-optimized parallel tetramer of the sodium channel helix 3. Colors light blue, a-carbon backbone red, acidic residues blue, basic residues yellow, polar and neutral residues and purple, lipophilic residues. This view is from the intracellular face of the membrane, at which the N terminus of each segment is predicted to be located. (From M. Montal, Proteins Structure, Function, and Genetics, vol. 8, University of California Press at San Diego, La Jolla, Calif., p. 226.)... 

The primer chosen for this investigation consisted of an equimolar mixture of phenyl- and amino-functional silanes, suggested as a potential superior primer for aluminum/epoxy adhesive joints [7], The amino-functional silane is known to be effective as an adhesion promoter for fiber-reinforced composite materials [1, 2] as well as for epoxy/metal adhesive joints [8, 9] and provides for strong chemical interaction between the adhesive and primer, while the phenyl functional silane should reduce the overall concentration of polar, hydrophilic functional groups in the interphase region and at the same time maintain or improve the ability of the resin and primer to interpenetrate due to its structural similarity to the adhesive resin. 

The role of zinc in the enzymes listed in Table 12 is very often that of a strong Lewis acid, in which substrates are coordinated, polarized and hence activated. In other cases, zinc may play a regulatory, structural or template role. Zinc may also have a structural function in other biological molecules, for example in the unwinding and subsequent rewinding of the double-stranded polymers involved in replication and transcriptional processes. There is also evidence for a role for zinc in the stabilization of membranes and cell walls.463 The high concentrations of zinc in certain snake venoms reflect the presence in the venom of proteolytic enzymes and hemorrhagic toxins that all require zinc for activity.464... 

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