In individual segments

Polarograms are sometimes distorted by polarographic maxima, where the current in individual segments of the I vs. E curves is much higher (several times) than the limiting diffusion current. A number of reasons exist for the development of these maxima. 

The pairs of the related parameters, such as time constant r, and weight coefficient a, are supposed as the co-ordinates of a point in a two-dimensional plot. Reciprocal time constant was assumed to be the length of the vector while the weigh coefficient defined the sine of the rotation angle (j) for the vector. The points of separate sensors from an array are displayed in individual segments of the circular plot. 

Thermal shocks have a highly negative effect on lifetime. These are sudden temperature changes in individual segments of a fuel cell. The development of considerable temperature gradients within given segments is also detrimental. 

Use of random flight statistics to derive rg for the coil assumes the individual segments exclude no volume from one another. While physically unrealistic, this assumption makes the derivation mathematically manageable. Neglecting this volume exclusion means that coil dimensions are underestimated by the random fight model, but this effect can be offset by applying the result to a solvent in which polymer-polymer contacts are somewhat favored over polymer-solvent contacts. 

Heavily crosslinked polymers, by contrast, tend to be very brittle and, unlike thermoplastics, this brittleness cannot be altered much by heahng. Heavily crosslinked materials have a dense three-dimensional network of covalent bonds in them, with little freedom for motion by the individual segments of the molecules involved in such structures. Hence there is no mechanism available to allow the material to take up the stress, with the result that it fails catastrophically at a given load with minimal deformation. 

As we have seen previously not all polymers are capable of being dissolved. In principle the capacity to dissolve is restricted to linear polymers only crosslinked polymers, while they may swell in appropriate solvents, are not soluble in the fullest sense of the word. While individual segments of such polymers may become solvated the crosslinks prevent solvent molecules from establishing adequate interactions with the whole polymer, thus preventing the molecules being carried off into solution. 

Figure 4 shows confocal images of the staining pattern for DDC (Fig. 4A), serotonin (Fig. 4B), and TH (Fig. 4C) in the segmental ventral ganglion of the CNS from third instar larvae. Panels B and C are the same CNS double stained with serotonin and TH. The DDC-expressing cells can be categorized into a set of paired ventral lateral serotonin cells (Fig. 4A,B labeled VL in 4A), and two morphologically distinct types of dopamine cells, the medial dopamine cells (Fig. 4A,C labeled M) and the dorsal-lateral dopamine cells (Fig. 4A,C labeled DL). Figure 4 demonstrates clearly that individual DDC cells synthesize either serotonin or dopamine, but not both. One additional set of cells shows TH immunoreactivity in the ventral ganglion. These six large vacuolated cells are located more laterally than any other DDC cells (Fig. 4C, unlabeled short arrows). It is likely that the immunoreactivity in these cells results from a non-specific cross-reaction, since these cells are not...

Adsorption of the polymer molecule causes a reduction of its conformational entropy (Norde 2003b). Flence, adsorption takes place only if the loss in conformational entropy is compensated by sufficient favorable interactions between polymer segments and the interface. Because the polymer molecule attaches with many segments at the interface, it adsorbs tenaciously with a very high affinity, even if the interaction of the individual segments with the interface is rather weak. The high affinity manifests itself by the adsorption being irreversible with respect to variations of the polymer concentration in solution. 

Under the action of an applied acoustic field the suggestion was that there would be regions within the polymer where rotation (and vibration) of individual segments were able to take place freely, in phase with the rapid oscillatory movement of the solvent. This segmental movement (termed micro Brovmian motion) was in addition to the movement of the macromolecule as a whole (macro Brownian motion). However, in that segmental motion is a cooperative effect and depends upon the interaction... 

Spann, W., Pachmann, K., Zabnienska, H., Pielmeier, A., and Emmerich, B. (1991) In-situ amplification of single copy gene segments in individual cells by polymerase chain reaction. Infection 19, 242-244. 

Figure 2. A diagrammatic representation of those segments of an overall reaction mechanism for barbed-end actin polymerization in the absence and presence of profilin and/or thymosin- 4. For clarity the overall scheme is indicated. Experimental data were obtained for individual segments (indicated in black type), and those parts of the scheme that were not evaluated in a particular experiment are shown in gray.

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