Morphology observations

Figure 2. A possible mechanism for lithium deposition (left) based on dissolution (right) lithium morphology observations in LiAsF6 - EC/2MeTHF electrolyte.

Figure 10. Four different ways of controlling the kinetics of polyol reduction and the corresponding morphologies observed for the Pt nanostructures. As the same amount of PVP was present in all four syntheses illustrated here, the striking differences in morphology were not caused by variation in the PVP concentration. It is assumed that the PVP molecules in these syntheses function only as a stabilizer to prevent the resultant nanoparticles from aggregating into larger structures. (Reprinted from Ref [270], 2005, with permission from Wiley-VCH.)...

In the case of extended chain crystals, we showed that a single crystal is easily formed even for Mn higher than 105. An ECSC shows a cigar-like and tapered shape morphology, observed by polarizing optical microscopy [22] and by transmission electron microscopy [48]. 

Morphology. Observations with the light microscope, under polarized light, showed that the end blocks in the case of both types of polymers crystallized in the form of the usual spheru-lites, but not as well as the analogous homopolymer, H2-l,4-polybutadiene. The formation of the spherulites was improved with increasing end-block content and/or higher molecular weight of the end blocks. 

Fig. 32 Schematic representation of molecular structure and morphology observed in PS-fo-PB-fc-PS linear and star-block copolymers. Oblique lines between blocks for LN2 and ST2 indicate tapered transition of dissimilar blocks. From [102], Copyright 2003 Wiley...

The volume inside the semicrystalline polymers can be divided between the crystallized and amorphous parts of the polymer. The crystalline part usually forms a complicated network in the matrix of the amorphous polymer. A visualization of a single-polymer crystallite done [111] by the Atomic Force Microscopy (AFM) is shown in Fig. 9. The most common morphology observable in the semicrystalline polymer is that of a spherulitic microstructure [112], where the crystalline lamellae grows more or less radially from the central nucleus in all directions. The different crystal lamellae can nucleate separately... 

After 45 days of experiment, the precipitate showed an XRD pattern typical of a poorly ordered mineral, such as schwertmannite. Identification of this AMD mineral was confirmed by its distinctive spike morphology, observed by SEM-SE (Fig. 3). After 240 days, XRD detected the resolved reflection at d spacing of 4.18 A, which is characteristic of goethite. Therefore, the maintenance of the precipitate in contact with the solution enabled its evolution to a more crystalline state. The trend of decrease in pH that is observed by the end of the experiment reflects the production of acidity, associated with the transformation of schwertmannite into goethite as it was observed by Bigham etal. (1996) (eq. 1). 

These three examples emphasize the idea that a complete description of amyloid fibril polymorphisms will only be achieved when 3D structures at atomic detail become available (Luhrs et al., 2005). Last but not least, since the various morphologies observed for amyloid fibrils are defining the end point of the assembly process, an essential need is to properly define the early stages of fibril formation, namely the oligomeric states of the peptide or protein in solution prior to assembly into fibrils. 

In the case of human amylin and Afi our understanding of the diversity in amyloid fibril architecture is the result of a recursive process, since the early morphological observations were followed by assessment of the assembly pathway which in turn yielded a better understanding of fibril polymorphism. However, this structural knowledge is secondary compared to the discovery of small oligomers, globular oligomers, and early protofibrils that appear to be extremely cytotoxic (Hartley etal., 1999 Lambert et al, 1998 Walsh et al, 1999). 

Calorimetric measurements and morphological observations showed that PS-fr-PCL, PB-fr-PCL and PS-fc-PB-fc-PCL copolymers exhibit microphase separation and crystallization if the molecular weight is high enough. Only in PS-fc-PCL diblock copolymers, a shift of the PS glass transition to lower temperatures has been observed. In PS-fo-PB-fo-PCL, the crystallizable block (i.e., PCL) is covalently linked to a rubbery block and it has a free end. For these reasons there is no significant reduction in the melting temperature and... 

Fig. 7 Some peculiar morphologies observed for crew-cut micelles. Baroclinic tubes (a). Tube-walled vesicles (b). Large compound micelles insert shows their internal structure (c) and interconnected tubules or plumber nightmare (d) (images downloaded from http //ottomaass.chem.mcgill.ca/groups/eisenberg/). Adapted from [35]...

The breakdown of these particles apparently caused by melting of the small crystalline segments in PVC causes the change of morphology observed. 

Note 3 The type of morphology observed depends upon the relative abundance of the different types of constitutional units and the conditions for the generation of the morphology. The most commonly observed morphologies are spheres, cylinders, and lamellae. 

Morphology observed in a blend of a block copolymer with the homopolymer of one of the blocks and characterized by alternating concentric shells of the copolymer and the homopolymer. 

Supernumerary rib is an expected morphological observation in developmental toxicity studies and one of the most common skeletal variants in rodents and rabbits with highly variable incidence between species and strain. The interpretation of supernumerary rib data can be complex because not only is this a spontaneously occurring variant in normal fetuses but it is also induced in rats and mice by various experimental conditions, including increased maternal stress (27) or high dosages of xenobiotics (14, 28, 29). 

Covalent functionalization of the nanotubes also affects the voltammetric features the richer curve morphology observed in the case of pristine nanotubes reflects the more complex electronic structure of the pristine materials, compared to functionalized ones (Scheme 9.17), in agreement with recent calculations that suggested that functionalization significantly affects the low-lying electronic states of the nanotubes.61... 

In these tissues the distribution of vesicles correspond closely to the patterns of matrix mineralization. Furthermore, it has been suggested that crystals of HA are deposited within the vesicles. Subsequently apatite is deposited within the vesicles and upon their surfaces to produce typical modular clusters of mineral. Such morphological observations strongly implicate the matrix vesicles in the formation of apatite crystals (Fig. 9). Once the first crystals are formed, they mineralize further by epitactic crystal growth458. ... 

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