Oriented attachment

Oriented attachment was first found for Ti02 particles generated in a hydrothermal process [94]. Chains of nanoparticles fused in crystallographic register were found and the fusion siufaces were identified to be the highest energy surfaces of the nanoparticles (Fig. 4). 

In the meantime, oriented attachment was found for a variety of systems such as Ti02 [94,97-99], FeOOH [100], CoOOH [101], Ag [102], ZnO [103], and ZnS [ 104] and was recently siunmarized in a review paper [ 105]. 

Although thin and long crystalline HAP fibers were obtained (the single crystalline nature of the fibers could not be shown due to their small diam- 

Although, so far, there are still comparatively few reports on the oriented attachment of nanoparticles, this new growth mechanism offers an additional tool for the design of single crystalhne advanced materials with anisotropic shape and it is certainly also worth exploring how far oriented attachment plays a role in biomineralization. 

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The TEM image of the PVP capped CdSe at 5 hr in figure 6A showed small, spherical particles with some aggregation. The aggregation is due to the oriented attachment between the spherical nanoparticles as a result of dipole-dipole interactions between the highly... 

Mayer D, Ataka K, Heberle J, Offenhaeusser A. 2005. Scanning probe microscopic studies of the oriented attachment and membrane reconstitution of cytochrome c oxidase to a gold electrode. Langmuir 21 8580-8583. 

Self-assembled nanorods of vanadium oxide bundles were synthesized by treating bulk V2O5 with high intensity ultrasound [34]. By prolonging the duration of ultrasound irradiation, uniform, well defined shapes and surface structures and smaller size of nanorod vanadium oxide bundles were obtained. Three steps which occur in sequence have been proposed for the self-assembly of nanorods into bundles (1) Formation of V2O5 nuclei due to the ultrasound induced dissolution and a further oriented attachment causes the formation of nanorods (2) Side-by-side attachment of individual nanorods to assemble into nanorods (3) Instability of the self-assembled V2O5 nanorod bundles lead to the formation of V2O5 primary nanoparticles. It is also believed that such nanorods are more active for n-butane oxidation. 

Lipowsky, P. Jia, S. Hoffmann, R. C. Jin-Phillipp, N. Y. Bill, J. Ruhle, M. 2006. Thin film formation by oriented attachment of polymer-capped nanocrystalline ZnO. Zeitschrift fur Metalllcunde 97(5) 607-613. 

Figure 10.3. PbSe nanowires synthesized by the oriented attachment and fusion of nanoparticles, (a) Schematic representation of the oriented attachment process.

When a GC 16A series gas chromatograph is used as the core, various laboratory-automation-oriented attachments such as bar-code reader and a magnetic-card reader become compatible a labour-saving system can be built, in which the best operational parameters are automatically set. Each satellite gas chromatograph (GC 14A series) operates as an independent instrument when a keyboard unit is connected. 

The immobilization strategies are of particular interest. The authors reasoned that the use of aldehydes to tether proteins to the solid phase could be ideal for certain protein-protein interaction studies. Since many protein-lysine residues are available for coupling to aldehydes via Schiff s base, a number of spatial orientations are possible. Such random oriented attachments would permit exposure of various surfaces of a protein to the solution, and new protein-protein interactions would be potentially possible. 

Haider A, Ravishankar N (2007) Ultrafine single-crystalline gold nanowire arrays by oriented attachment. Adv Mater 19(14) 1854-1858... 

For textile materials used as interior wall-coverings in U.K. buildings including railway carriages, where the fabric could be in a vertical orientation attached to the wall panel, measurement of rate of flame spread under external heat flux is one of the requirements. For such applications, the test method (BS 476 Part 7) essentially requires a vertically oriented specimen exposed to gas-fired radiant panel with incident heat flux of 32.5kW/m2 for lOmin. In addition, a pilot flame is applied at the bottom corner of the specimen for 1 min 30 s and rate of flame spread is measured. The same principle is used in the French test for carpets, NF P 92-506. 

Synthesis forms a vital aspect of the science of nanomaterials. In this context, chemical methods have proved to be more effective and versatile than physical methods and have therefore, been employed widely to synthesize a variety of nanomaterials, including zero-dimensional nanocrystals, one-dimensional nanowircs and nanotubes as well as two-dimensional nanofilms and nanowalls. Chemical synthesis of inorganic nanomaterials has been pursued vigorously in the last few years and in this article we provide a perspective on the present status of the subject. The article includes a discussion of nanocrystals and nanowires of metals, oxides, chalcogenides and pnictides. In addition, inorganic nanotubes and nanowalls have been reviewed. Some aspects of core-shell particles, oriented attachment and the use of liquid-liquid interfaces are also presented. 

PbSe and cubic ZnS nanowires as well as complex one-dimensional nanostructures can be obtained in solution through oriented attachment of na ocryslals. "U4, In Fig. 23, star-shaped PbSe uanocrystals and branched nanowircs are shown. 

Hydrogel-assisted synthesis of nanotubes and nanorods of CdS, ZnS and CuS, showing some evidence for oriented attachment... 

By oriented attachment, Yu et al. [8] could obtain ZnS nanorods with cubic blend structure, in which the (11 1) planes of the component ZnS nanocrystals are nearly perfectly aligned. Pradhan et al. [9] have reported the formation of colloidal CdSe quantum wires by the oriented attachment of magic-sized clusters of CdSe. 

Zhou et al. reported the synthesis of flower-like ceria NPs by thermal decomposition of (NH4)2Ce(N03)g in OA/OM solvents at 230-300 °C. The small ceria nanoparticles form, assemble, and fuse mainly via (111) faces by oriented attachment. Monitoring by in situ electrical resistance measurements shows that the conductive species are diminished when the flower-like nanostructures form (Zhou et al., 2008a Figure 6). Ceria nanoflowers and nanocubes are also obtained in octadecylamine, with higher temperature for nanoflower and lower temperature for nanocubes. The obtained colloidal nanoparticles can be self-assembled into nanospheres assisted by SDS surfactants (Wang et al., 2008a). 

The essence of the differentiation of these groups is that the enzyme holds the substrate in a specific orientation. Attachment at three points, as depicted in the diagram, is a readily visualized way of achieving a particular orientation of the substrate, but it is not the only means of doing so. 

The most obvious function of GPI anchors is to provide a stable, oriented attachment of proteins onto membranes, usually the extracellular surface of plasma membranes. However, there is much discussion over whether this highly conserved, multiple-step, complex mechanism for anchoring proteins has additional functions and it has been proposed [96,98,104,105] that GPI anchors ... 

Perm RL, Banfield JF, Kerrick, DM (1999) TEM investigation of Lewiston, Idaho Fibrolite Implications for grain boundary energetics and A SiOs phase relations. Am Mineral 84 152-159 Perm RL, Banfield JF (1998a) Imperfect oriented attachment Dislocation generation in defect-free nanocrystals. Science 281 969-971... 

Penn RL, Banfield JF (1998b) Oriented attachment and growth, twinning, polytypism, and formation of metastable phases Insights from nanociystalline Ti02. Am Mineral 83 1077-1082 Post JE, Bish DL (1989) Rietveld refinement of crystal stmctnres nsing powder X-ray diffraction data. Rev Mineral 20 277-308... 

Penn RL, Banfield JF (1998) Imperfect oriented attachment Dislocation generation in defect-free nanocrystals. Science 281 969-971... 

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