Denis Zolotov

Comparison of the data of X-ray microtomography and fluorescence analysis in the study of bone-tissue structure

The possibility of localizing clusters of heavy atoms is substantiated by comparing the data of X-ray microtomography at different wavelengths, scanning electron microscopy, and X-ray fluorescence analysis. The proximal tail vertebrae of Turner’s thick-toed gecko (Chondrodactylus turneri) have been investigated for the first time by both histological and physical methods, including X-ray microtomography at different wavelengths and elemental analysis. This complex methodology of study made it possible to reveal the regions of accumulation of heavy elements in the aforementioned bones of Turner’s thick-toed gecko.

Overview of machine vision methods in x-ray imaging and microtomography

Digital X-ray imaging became widely used in science, medicine, non-destructive testing. This allows using modern digital images analysis for automatic information extraction and interpretation. We give short review of scientific applications of machine vision in scientific X-ray imaging and microtomography, including image processing, feature detection and extraction, images compression to increase camera throughput, microtomography reconstruction, visualization and setup adjustment.

The possibility of identifying the spatial location of single dislocations by topo-tomography on laboratory setups

The spatial arrangement of single linear defects in a Si single crystal (input surface {111}) has been investigated by X-ray topo-tomography using laboratory X-ray sources. The experimental technique and the procedure of reconstructing a 3D image of dislocation half-loops near the Si crystal surface are described. The sizes of observed linear defects with a spatial resolution of about 10 μm are estimated.

Monochromatic computed microtomography using laboratory and synchrotron sources and X-ray fluorescence analysis for comprehensive analysis of structural changes in bones

Structural changes in vertebrate bone tissues caused by bone growth or by weightlessness were studied using a combination of X-ray tomography at different wavelengths and X-ray fluorescence analysis.

Retrieval of 3D deformations of single crystal defects by X-ray topo-tomography

A challenge in X-ray topo-tomography is the issue of quantitatively determining the 3D-deformation-distribution field associated with single defects of crystal lattices. In the present report an endeavor is made to retrieve a 3D-deformation-distribution field around single line defects (dislocations) in crystals by using the X-ray topo-tomography method. The general layout of the X-ray topotomography experiment is depicted in Fig. 1[1]. For our purposes we have used plane-parallel samples of crystal Si with surface orientation (111), the sample thickness being 1 mm, in which the linear dislocations have been inserted according to [2]. The experiments were carried out at the X-ray wavelength of MoKα1 ( =0.071 nm). xperimental series of the X-ray (2 20)-reflection topography images with the rotation angle step 2° around the diffraction vector, the total angular range 360°, have been got out. Furthermore, such the 2Dtopographic images are used for getting 3D-images by means of the modified algebraic method SART developed in [3]. In parallel, for 3D reconstruction the corresponding 2D-topographic dislocation images are simulated by use of the Born-approximation analytical and numerical solutions based on Takagi-Taupin equations describing the two-beam X-ray diffraction by the deformed crystals. Certainly, all the above approaches are applied to the comparative analysis of opportunities of determining 3D-deformation-distribution field around the dislocations under consideration.

Computed microtomography and x-ray fluorescence analysis for comprehensive analysis of structural changes in bone

This paper presents the results of a comprehensive analysis of structural changes in the caudal vertebrae of Turners thick-toed geckos by computer microtomography and X-ray fluorescence analysis. We present algorithms used for the reconstruction of tomographic images which allow to work with high noise level projections that represent typical conditions dictated by the nature of the samples. Reptiles, due to their ruggedness, small size, belonging to the amniote and a number of other valuable features, are an attractive model object for long-orbital experiments on unmanned spacecraft. Issues of possible changes in their bone tissue under the influence of spaceflight are the subject of discussions between biologists from different laboratories around the world.

Characterization of oil nano-structures with monochromatic x-ray micro-tomography

Here we report work done toward detection and characterization of micro-and nano-structures in bitumen, including mineral particles-clay and sand as well as metal-organic micro-and nano-structures containing porphyrines. X-ray micro-tomograph with monochromatic radiation has been used for detection of the structures. In order to detect and characterize nano-and micro-structures tomograph’s operational wavelength has been tuned to absorption wavelength of “chemical element of interest” X-ray spectrum: whatever it is Si or porphyrine-forming metals like V, Ni, Co. Contrast between X-ray absorption of micro-structures containing specific element and average bitumen’s environment absorption provides a tool for measurement of element mass concentration as well as size and mass density distributions of micro-and nano structures not only on surface but in bitumen volume. Specifically the most interest is in measurement of vanadyl porphyrines and other metal containing chemicals in asphaltene micro-structures changing per asphalten concentration due to bitumen processing.