New findings about the intrascaphoid arterial system

2018 ◽  
Vol 43 (10) ◽  
pp. 1059-1065 ◽  
Author(s):  
Zirun Xiao ◽  
Ge Xiong ◽  
Weiguang Zhang

We investigated the intraosseous arteries of six normal cadaveric scaphoids using red lead injection and three-dimensional reconstruction with micro-computed tomography. The arterial entrances were generally located around the dorsal ridge, the insertion of the scaphocapitate ligament and the radial part of the radioscaphocapitate ligament. Two to three trunk arteries entered the scaphoid on dorsal ridge at the level of the waist. The distal part of the scaphoid was mainly supplied by arteries from the waist. The blood supply of about 40% of proximal part of the scaphoid was poor. The blood supply from the scaphoid dorsal ridge plays an important role, not only for the proximal part of the scaphoid, but also for the waist and even the distal pole. The intrascaphoid arterial pattern may be contributory to nonunion, especially in proximal pole fractures.

2017 ◽  
Vol 88 (11) ◽  
pp. 1263-1277 ◽  
Author(s):  
Licheng Zhu ◽  
Xungai Wang ◽  
Juan P Hinestroza ◽  
Maryam Naebe

Fabric porosity affects the performance of textile materials, and characterization of the pore size in fabrics is a particularly difficult task. In this study, micro-computed tomography and reconstructed three dimensional (3D) images were used to accurately measure the fabric porosity and to determine the number, diameters, and locations of the pores. To validate the flexibility of the proposed technique, we analyzed woven, knitted, and bifacial fabrics made of wool/acrylic and polyester. Distributions of pore diameters and pore connections in the bifacial fabric confirmed that this fabric comprises a combination of woven and knitted structures. The volume porosities of the woven, knitted, and bifacial fabrics obtained from 3D reconstruction were similar to those calculated based on other techniques such as mathematical models. While the different fabric structures used in this study showed similar volume porosities, they had different air permeability. However, porosity analysis suggested new evidence to validate permeability measurements in fabrics. A new method for determining fabric surface and measuring fabric thickness is proposed, which accesses the number and diameters of inter-fiber pores. Having access to this type of information can potentially be used to engineer and to tune the performance of textiles.


Author(s):  
Robert Glaeser ◽  
Thomas Bauer ◽  
David Grano

In transmission electron microscopy, the 3-dimensional structure of an object is usually obtained in one of two ways. For objects which can be included in one specimen, as for example with elements included in freeze- dried whole mounts and examined with a high voltage microscope, stereo pairs can be obtained which exhibit the 3-D structure of the element. For objects which can not be included in one specimen, the 3-D shape is obtained by reconstruction from serial sections. However, without stereo imagery, only detail which remains constant within the thickness of the section can be used in the reconstruction; consequently, the choice is between a low resolution reconstruction using a few thick sections and a better resolution reconstruction using many thin sections, generally a tedious chore. This paper describes an approach to 3-D reconstruction which uses stereo images of serial thick sections to reconstruct an object including detail which changes within the depth of an individual thick section.


Author(s):  
S. Cusack ◽  
J.-C. Jésior

Three-dimensional reconstruction techniques using electron microscopy have been principally developed for application to 2-D arrays (i.e. monolayers) of biological molecules and symmetrical single particles (e.g. helical viruses). However many biological molecules that crystallise form multilayered microcrystals which are unsuitable for study by either the standard methods of 3-D reconstruction or, because of their size, by X-ray crystallography. The grid sectioning technique enables a number of different projections of such microcrystals to be obtained in well defined directions (e.g. parallel to crystal axes) and poses the problem of how best these projections can be used to reconstruct the packing and shape of the molecules forming the microcrystal.Given sufficient projections there may be enough information to do a crystallographic reconstruction in Fourier space. We however have considered the situation where only a limited number of projections are available, as for example in the case of catalase platelets where three orthogonal and two diagonal projections have been obtained (Fig. 1).


Author(s):  
A.M. Jones ◽  
A. Max Fiskin

If the tilt of a specimen can be varied either by the strategy of observing identical particles orientated randomly or by use of a eucentric goniometer stage, three dimensional reconstruction procedures are available (l). If the specimens, such as small protein aggregates, lack periodicity, direct space methods compete favorably in ease of implementation with reconstruction by the Fourier (transform) space approach (2). Regardless of method, reconstruction is possible because useful specimen thicknesses are always much less than the depth of field in an electron microscope. Thus electron images record the amount of stain in columns of the object normal to the recording plates. For single particles, practical considerations dictate that the specimen be tilted precisely about a single axis. In so doing a reconstructed image is achieved serially from two-dimensional sections which in turn are generated by a series of back-to-front lines of projection data.


Author(s):  
Mark Ellisman ◽  
Maryann Martone ◽  
Gabriel Soto ◽  
Eleizer Masliah ◽  
David Hessler ◽  
...  

Structurally-oriented biologists examine cells, tissues, organelles and macromolecules in order to gain insight into cellular and molecular physiology by relating structure to function. The understanding of these structures can be greatly enhanced by the use of techniques for the visualization and quantitative analysis of three-dimensional structure. Three projects from current research activities will be presented in order to illustrate both the present capabilities of computer aided techniques as well as their limitations and future possibilities.The first project concerns the three-dimensional reconstruction of the neuritic plaques found in the brains of patients with Alzheimer's disease. We have developed a software package “Synu” for investigation of 3D data sets which has been used in conjunction with laser confocal light microscopy to study the structure of the neuritic plaque. Tissue sections of autopsy samples from patients with Alzheimer's disease were double-labeled for tau, a cytoskeletal marker for abnormal neurites, and synaptophysin, a marker of presynaptic terminals.


Author(s):  
N. H. Olson ◽  
T. S. Baker ◽  
Wu Bo Mu ◽  
J. E. Johnson ◽  
D. A. Hendry

Nudaurelia capensis β virus (NβV) is an RNA virus of the South African Pine Emperor moth, Nudaurelia cytherea capensis (Lepidoptera: Saturniidae). The NβV capsid is a T = 4 icosahedron that contains 60T = 240 subunits of the coat protein (Mr = 61,000). A three-dimensional reconstruction of the NβV capsid was previously computed from visions embedded in negative stain suspended over holes in a carbon film. We have re-examined the three-dimensional structure of NβV, using cryo-microscopy to examine the native, unstained structure of the virion and to provide a initial phasing model for high-resolution x-ray crystallographic studiesNβV was purified and prepared for cryo-microscopy as described. Micrographs were recorded ∼1 - 2 μm underfocus at a magnification of 49,000X with a total electron dose of about 1800 e-/nm2.


Author(s):  
Daniel Beniac ◽  
George Harauz

The structures of E. coli ribosomes have been extensively probed by electron microscopy of negatively stained and frozen hydrated preparations. Coupled with quantitative image analysis and three dimensional reconstruction, such approaches are worthwhile in defining size, shape, and quaternary organisation. The important question of how the nucleic acid and protein components are arranged with respect to each other remains difficult to answer, however. A microscopical technique that has been proposed to answer this query is electron spectroscopic imaging (ESI), in which scattered electrons with energy losses characteristic of inner shell ionisations are used to form specific elemental maps. Here, we report the use of image sorting and averaging techniques to determine the extent to which a phosphorus map of isolated ribosomal subunits can define the ribosomal RNA (rRNA) distribution within them.


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