Polymeric assemblies

Just as myosins are able to move along microfilaments, there are motor proteins that move along microtubules. Microtubules, like microfilaments, are polar polymeric assemblies, but unlike actin-myosin interactions, microtubule-based motors exist that move along microtubules in either direction. A constant traffic of vesicles and organelles is visible in cultured cells especially using time-lapse photography. The larger part of this movement takes place on micrombules and is stimulated by phorbol ester (an activator of protein kinase C), and over-expression of N-J aj oncoprotein (Alexandrova et al., 1993). 

The optical and electrochemical properties of porphyrins make these chromophores useful building blocks for the synthesis of electro- and photoactive polymers. Two types of linear polymers have been constructed using the self-assembly approach homo-polymeric assemblies and hetero- or shish kebab polymers. 

Fig. 1 Typical examples of nanometer-scale polymeric assemblies polymer micelles, polymersomes,...

Hitherto no monometalated molecular pnictide exists without solvation of the main group metal atom. Therefore, the monomeric species L (Fig. 2) can only be stabilized if the Li ion has its coordination sphere enlarged through donor solvation. More importantly, the lithium phosphanides of the type K undergo oligomerization processes to form dimer, tetramer, hexamer, or polymeric assemblies M—Q (Fig. 2), which dissociate in solution more easily than related amides (2, 11, 12). 

Figure 7.10 Tapered macromonomers and their cylindrical polymerized assemblies...

Kato, T. Mizoshita, N. Kanie, K. Hydrogen-bonded liquid crystalline materials Supramolecular polymeric assembly and the induction of dynamic function. Macromol. Rapid Commun. 2001, 22, 797-814. 

Cutin-Wax Interactions. In order to obtain a more complete structural picture of plant cuticle, 13C CPMAS data were also obtained for the polymeric assembly prior to removal of waxes (Figure 5). A second (CH2)n peak appeared in the spectrum, and additional signal intensity in the carboxyl region produced a single broadened peak. Bulk methylene carbons from cutin and wax components exhibited identical values of Tip(H), indicating that they were mixed intimately and shared a common 1H spin reservoir... 

Dramatic examples have also been reported for main-chain supramolecular polymers (SPs Lehn 1993 Ciferri 2005 Fig. 3.1), in which specific and directional molecular recognition events between end groups define the main chain of a linear polymeric assembly. Although main-chain SPs had been created and characterized previously (Broze et al. 1983 Fouquey et al. 1990 Alexander et al. 1993 Bladon and Griffin 1993 St Pourcain and Griffin 1995), it was a groundbreaking paper in 1997 that demonstrated the mechanical potential of supramolecular interactions and catalyzed much of the current interest in the field (Sijbesma et al. 1997). 

I and I of the octahedral interstices are occupied, respectively. There are various possibilities for the distribution of the occupied sites, and the specification of a layer sequence alone is not very informative. Fig. 17.9 shows some examples which also allow us to recognize an important principle concerning the packing of molecules all octahedral interstices that immediately surround a molecule must be vacant, and then occupied interstices have to follow otherwise either the molecules would be joined to polymeric assemblies or not all of the atoms of the sphere packing would be part of a molecule. These... 

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