Interior layers contrast structures

Thus we see that these solutions have not only boundary layers, but also interior layers. Solutions having such interior layers are called contrast structures. A contrast structure of the type represented in Fig. 8 is called a spike, and a contrast structure of the type represented in Fig. 9 is called a step (or threshold). 

The interior membrane layers of the grana are rich in photosystem II by contrast, the stroma lamellae (structures that connect grana) are rich in photosystem I (Figure 17.16). 

Amphiphilic molecules, when dissolved in organic solvents, are capable of self-assembly to form reversed micelles. The reversed micelles are structurally the reverse of normal micelles in that they have an external shell made up of the hydrocarbon chains of the amphiphilic molecules and the hydrophilic head-groups localized in the interior of the aggregate. Water molecules are readily solubilized in this polar core, forming a so-called water pool. This means that reversed micelles form microcompartments on a nanometer scale. The reversed micelles can host all kinds of substrate molecules whether hydrophilic, hydrophobic, or amphiphilic due to the dynamic structure of the water pool and the interface formed by the surfactant layer, in contrast with a liposome system. The properties of water molecules localized in the interior of reversed micelles are physicochemically different from those of bulk water, the difference becoming progressively smaller as the water content in the micellar system increases [1,2]. The anomalous water at low JVo =[water]/[surfactant] obviously influences the chemical behavior of host molecules in the water pools. 

A spectacular example of a ridge and valley textile structure, 320 m in length, covers the central concourse of Denver Airport Terminal (1994) and is intended to mirror the snow-capped Rocky Mountains in the distance (Brown, 1994). This is a double-layer membrane used to improve the thermal and acoustic performance of the space (Berger, 2000, pp. 220-221). It is particularly employed to reduce the impact of aircraft engine noise on the interior. As Fig. 7.12 shows, here the distinct contrast between the bright membrane (bright, even though it is double-layer) and the duller surfaces at concourse level can clearly be seen, as discussed previously in Section 7.6.2. 

The self-assembled nanotubes had lengths from 0.85 to 1.1 pm and widths around 0.2-0.4 pm. Some TEM images showed contrast, which demonstrates that the tubes were constructed from small particles and that they had a hollow interior. This work demonstrated that polymeric Janus particles behave like amphiphilic block copolymers or lipids. They are capable of forming layered structures with a relatively reduced curvature, such as vesicles or in this case nanotubes, even though the exact mechanism is still under investigation. 

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