Three Dimensional Reconstruction of Particles

Three Dimensional Reconstruction of Particles video camera... 

The technique presented for the three dimensional reconstruction of particles by analyzing the projected areas from three orthogonal directions proved to be veiy reliable. The method was used to determine the particle volume and to calculate the three dimensional reconstructions of macroscopic objects and limestone and quartz particles utilized in simulation programs. 

Radermacher M, Ruiz T. (2006) Three-dimensional reconstruction of single particles in electron microscopy image processing. Methods Mol. Biol. 319, 427-61. 

Martin-Benito, J., E. Area, J. Ortega, O. Llorca, J. M. Valpuesta, J. L. Carrascosa, and J. Ortin. 2001. Three-dimensional reconstruction of a recombinant influenza virus ribonucleoprotein particle. EMBO Rep 2 313-7. 

Fig. 5. Three-dimensional reconstructions of apo-CCT and ATP-CCT. Side, top, and tilted views are shown additionally, bottom views are shown for the markedly asymmetric ATP-CCT particle. Reprinted from Llorca et al. (1999b), with permission.

Fig. 28-3. Structure of an alphavirus. Shown is the three-dimensional reconstruction of Sindbis virus at 28 A resolution from computer-processed images taken by electron cryomicroscopy, (a) The original electron micrograph shows virus particles in vitreous ice. (b) The surface view of the virus shows details of the 80 trimeric spikes, which are arranged in a T=4 icosahedron. Each spike protrudes 50 A from the virion surface and is believed to be composed of three E1-E2 glycoprotein heterodimers, (c) The cross-sectional view shows the outer surface spikes (yellow) and the internal nucleocapsid (blue), composed of the capsid and viral RNA. The space between the spikes and the nucleocapsid would be occupied by the lipid envelope. The green arrows mark visible points of interaction between the nucleocapsid and trans-membranal tails of the glycoprotein spikes, (d) The reconstructed capsid also exhibits a T=4 icosahedral symmetry. Computer models Courtesy of Angel M. Paredes, Cell Research Institute and Department of Microbiology, The University of Texas at Austin, Austin, Tex. Similar but not identical versions of these computer models were published in Paredes AM, Brown DT, Rothnagel R, et al. Three-dimensional structure of a membrane-containing virus. Proc Natl Acad Sci USA. 1993 90 9095-9099.

Puller, S.D., Butcher, S.J., Cheng, R.H., and Baker T.S. (1996). Three-dimensional reconstruction of icosahedral particles - The uncommon line. J. Structural Biol. 116, 48-55. 

Radermacher, M. (1988). Three-dimensional reconstruction of single particles from random and non-random tilt series. J. Elec. Microsc. Tech. 9, 354—394. 

In the last decade confocal laser scanning microscopy (CLSM) was shown to be a helpful tool for various further tasks of microparticle characterization (Lamprecht et al., 2000a, b, c). It minimizes the light scattered from out-of-focus structures, and permits the identification of several compounds through use of different fluorescence labels. Therefore, CLSM can be applied as a non-destructive visualization technique for microparticles. Moreover, CLSM allows visualization and characterization of structures not only on the surface, but also inside the particles, provided the carrier matrices are sufficiently transparent and can be fluorescently labeled by collecting several coplanar cross-sections, a three-dimensional reconstruction of the inspected objects is possible. Figure 6.13 shows the application of CLSM to investigatation of the cross-sectional structures of spray-dried powders of maltodextrin (MD) with a dextrose equivalent value of DE = 2 and 20. Florescein sodium salt was dissolved in the feed solution as a fluorescent probe of the carrier... 

C. Number of Particle Images Needed for a Three-Dimensional Reconstruction... 

Detailed three-dimensional measurements of ICEO flows are now possible in microfluidic devices. Using particle-image velocimetry applied to thin optical slices, the ICEO flow field around a platinum cylinder has recently been reconstructed experimentally (Fig. 5b) and found to agree well with the theory, up to a scaling factor which could perhaps be attributable to compact-layer effects [6]. There has also been extensive experimental work on AC electro-osmotic flows in microfluidic devices, as discussed in a separate article. 

Here the particle is viewed from different angles in the same plane. From the resulting projected areas a three dimensional reconstruction can be calculated [2 3]. When the projections from many different angles are included, the visible part of the particles can be reconstructed very precisely. However, there are regions of the particle that are not registered while other parts of the surface are covered more than once. 

Results are presented for different kinds of analyzed objects. Two macroscopic test objects were manufactured from teflon and PVC with diameters of approximately lO cm Fig. 5 shows the macroscopic objects in different orientations together with the three dimensional reconstruction in corresponding orientations. To verify the method, the volumes of these objects were calculated as well as experimentally determined. The maximum deviation between the two methods was 3 %. Fig. 6 shows the reconstruction of a limestone particle with an equivalent diameter Xp = 90 pm. The reconstructions reveal the typical shape characteristics for this material with a relative smooth surface. 

The large size of ribosomal particles is an obstacle for crystallographic studies, but permits direct investigation by electron microscopy. A model (Fig. 13) obtained by three-dimensional image reconstruction of two-dimensional sheets (e.g. ) may be used for gradual phasing of low resolution crystallographic data. 

Using advances in computer reconstruction methods (see e.g. Kikkinides and Burganos, 2000 Torquato, 2001) and past experience with discrete particle deposit simulations (Konstandopoulos, 2000), we have developed algorithmic as well as process-based reconstruction techniques to generate three-dimensional (3D) digital materials that are faithful representations of DPF microstructures. We refer to this approach as DPF microflow simulation (MicroFlowS). MicroFlowS is thus a short name for a computational approach, which combines... 

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