NanoCT: Visualizing of internal 3D-Structures with Submicrometer Resolution

2007 ◽  
Vol 990 ◽  
Author(s):  
Oliver Brunke ◽  
Dirk Neuber ◽  
David K. Lehmann

ABSTRACTHigh-resolution Computed Tomography (CT) widely expands the spectrum of detectable internal micro-structures. The new nanotom CT system allows the analysis of samples with the exceptional voxel-resolution of less than 0.5 microns per volume pixel (voxel). Thus internal detail related to a variation in material, density or porosity can be visualised and precisely measured. This opens a new dimension of 3D-microanalysis and will partially substitute traditional destructive methods in industrial quality control and research.The nanotom® is the first 180 kV nanoCT system world-wide which is tailored specifically to the highest-resolution applications in material science, micro electronics, geology and biology. Therefore it is particularly suitable for nanoCT-examinations of material samples of any type like synthetic materials, ceramics, composite materials, mineral and organic samples.Several results of high-resolution nanoCT demonstrate the capability to analyse the 3D-microstructure of materials with only minimal sample preparation. For instance, it is possible to image different metal phases in solder joints, the texture of fibres in composites or the volume and distribution of voids in castings.The volume data set is visualised by slices or compiled in a three-dimensional view which can be displayed in various ways. By means of volume visualisation software, the three-dimensional structure of the reconstructed volume can be easily analysed for pores, cracks, and materials density and distribution with the highest magnification and image quality available.By granting the user the ability to navigate the internal structure of an object slice-by-slice with highest resolution in a non-destructive manner, the nanotom creates new possibilities for analysis which have so far been unreachable.

Author(s):  
Bing K. Jap ◽  
Peter Walian ◽  
Thomas Earnest

Density modification methods were used to improve the three-dimensional map of PhoE porin which has been obtained by electron crystallographic techniques. The electron crystallographic data set consists of diffraction amplitudes that extend to a resolution of∽ 2.8 Å and phase information derived from 22 tilted and 8 untilted images at 3.5 Å resolution. However the data set was restricted to tilt angles less than ∽ 60 degrees, and therefore there is a missing cone regionin our 3-D data set. Non-crystallographic symmetry averaging and solvent flattening techniques were used to improve and extend the phase information, allowing for the calculation of high resolution Coulomb potential maps of membrane-embedded PhoE. These maps were used as a basis for building a partial molecular model, which was subsequently used to supply phase information to be combined with the experimentally determined phases. The combined phases were then used to calculate improved maps. As the maps continue to improve, more of the backbone and some of the side chains were built into the maps.


Author(s):  
Kenneth H. Downing ◽  
Hu Meisheng ◽  
Hans-Rudolf Went ◽  
Michael A. O'Keefe

With current advances in electron microscope design, high resolution electron microscopy has become routine, and point resolutions of better than 2Å have been obtained in images of many inorganic crystals. Although this resolution is sufficient to resolve interatomic spacings, interpretation generally requires comparison of experimental images with calculations. Since the images are two-dimensional representations of projections of the full three-dimensional structure, information is invariably lost in the overlapping images of atoms at various heights. The technique of electron crystallography, in which information from several views of a crystal is combined, has been developed to obtain three-dimensional information on proteins. The resolution in images of proteins is severely limited by effects of radiation damage. In principle, atomic-resolution, 3D reconstructions should be obtainable from specimens that are resistant to damage. The most serious problem would appear to be in obtaining high-resolution images from areas that are thin enough that dynamical scattering effects can be ignored.


2011 ◽  
Vol 191 (4) ◽  
pp. 1168-1179 ◽  
Author(s):  
Craig R. Brodersen ◽  
Eric F. Lee ◽  
Brendan Choat ◽  
Steven Jansen ◽  
Ronald J. Phillips ◽  
...  

Author(s):  
Kathryn Grandfield ◽  
Anders Palmquist ◽  
Håkan Engqvist

Interfacial relationships between biomaterials and tissues strongly influence the success of implant materials and their long-term functionality. Owing to the inhomogeneity of biological tissues at an interface, in particular bone tissue, two-dimensional images often lack detail on the interfacial morphological complexity. Furthermore, the increasing use of nanotechnology in the design and production of biomaterials demands characterization techniques on a similar length scale. Electron tomography (ET) can meet these challenges by enabling high-resolution three-dimensional imaging of biomaterial interfaces. In this article, we review the fundamentals of ET and highlight its recent applications in probing the three-dimensional structure of bioceramics and their interfaces, with particular focus on the hydroxyapatite–bone interface, titanium dioxide–bone interface and a mesoporous titania coating for controlled drug release.


Author(s):  
Badreldeen Ahmed ◽  
Ulrich Honemeyer

Abstract Three-dimensional, multiplanar sonography, using a volume data set acquired with a 3D probe, has revolutionized ultrasonographic imaging and takes sonographers to a new perception of the fetus in 3 dimensions. Real time scanning, until the late nineties only possible in B-mode, can now be performed in 3D with up to 40 frames/sec. Fetal neurology emerged as a new perinatal research field with the 4D visualization of fetal behavior. Doppler ultrasound, diversified and refined from continuous wave and pulsed Doppler to Color – and Power Doppler, when added to 3D sonography, creates fascinating options of noninvasive fetal vascular mapping (sonoangiography) and vascular assessment of placenta. The diagnostic and demonstrative potential of an acquired 3D volume data set can be maxed with the help of postprocessing and rendering software. After storage, the evaluation of fetal 3D data sets can happen without the patient, with the option of specialist consultation, using telemedicine. In the article, the new 3D “modes” like surface rendering, maximum mode, 3D Color and Power Doppler, STIC, volume rendering, and glass body rendering, are described and illustrated in their display of normal fetal anatomy.


2021 ◽  
Vol 7 ◽  
Author(s):  
Castrense Savojardo ◽  
Matteo Manfredi ◽  
Pier Luigi Martelli ◽  
Rita Casadio

Solvent accessibility (SASA) is a key feature of proteins for determining their folding and stability. SASA is computed from protein structures with different algorithms, and from protein sequences with machine-learning based approaches trained on solved structures. Here we ask the question as to which extent solvent exposure of residues can be associated to the pathogenicity of the variation. By this, SASA of the wild-type residue acquires a role in the context of functional annotation of protein single-residue variations (SRVs). By mapping variations on a curated database of human protein structures, we found that residues targeted by disease related SRVs are less accessible to solvent than residues involved in polymorphisms. The disease association is not evenly distributed among the different residue types: SRVs targeting glycine, tryptophan, tyrosine, and cysteine are more frequently disease associated than others. For all residues, the proportion of disease related SRVs largely increases when the wild-type residue is buried and decreases when it is exposed. The extent of the increase depends on the residue type. With the aid of an in house developed predictor, based on a deep learning procedure and performing at the state-of-the-art, we are able to confirm the above tendency by analyzing a large data set of residues subjected to variations and occurring in some 12,494 human protein sequences still lacking three-dimensional structure (derived from HUMSAVAR). Our data support the notion that surface accessible area is a distinguished property of residues that undergo variation and that pathogenicity is more frequently associated to the buried property than to the exposed one.


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