Use Of Microtomography Research Articles

Investigation of Rhodnius prolixus head anatomy using microtomography.

In the last years, microtomography has proved to be a powerful technique on insects' studies, allowing a detailed view of the structures' internal with a high resolution. One of the most important advantages about the use of microtomography in these studies is the fact that the dissection is not necessary, which decreases considerably the number of samples used on the insects' research. Some insects are used constantly in studies about morphology, metamorphosis, and reproduction, because they work as a model for others, and Rhodnius prolixus is one of the most studied in this group. This insect is also one of the main insect vectors of Chagas disease that kills around 12,000 people every year in Latin America. Some studies using laboratory microtomography conventional scanners combining with the correct staining methods have proved that it could be a powerful tool in biological research, allowing the visualisation of low-density tissues. The main goal of the present work was to use staining protocols to study Rhodnius prolixus with laboratory microtomography conventional scanners. The experiments were carried out at the imaging lab in the Theoretical Biology Department, University of Vienna, using an Xradia MicroXCT and at the University of Oslo, using a Skyscan 2211.

Pathological Evaluation by Microtomography of Ranula. Clinical Case Report

This study aims to demonstrate, through a clinical case report, the applicability of the use of microtomography (µCT) in the histopathological evaluation of a ranula lesion on the oral floor and to evaluate the use of 2 % elemental iodine solution as a contrast agent, in order to obtain a better contrast effect in a tissue sample, thus facilitating the identificat ion of anatomical structures, the histomorphological evaluation and the potential use of µCT in the imaging diagnosis of lesions. Different parameters were evaluated for obtaining images in SkyScan 1172, in a biopsied piece, when impregnated in a 10 % formalin solution and in a 2 % elemental iodine solution, when impregnated for 24h and 48h. Contrast agent impregnation was evaluated using the Hounsfield unit. The use of µCT allowed the identification of sialoliths dispersed inside the biopsy specimen, while the impregnation with Elemental iodine 2 % for 24h resulted in a better contrast when compared to the other conditions. The use of the Hounsfield unit allowed an adequate evaluation of the contrast obtained when the different parameters of impregnation and image acquisition were applied. The comparison between the 3D images with and without a specific marker highlighted a better evidencing of the soft tissues, with an improvement in the contrast of the images, also allowing the ident ification of the glandular duct obstructed by the sialoliths, allowing a conclusive histopathological evaluation of the biopsied lesion.

Rapid construction of 4D high-quality microstructural image for cement hydration using partial information registration

Studying on the microstructural evolution of cement paste during hydration is of considerable significance for understanding its mechanism and designing such material in cement industry. With the use of microtomography and image registration, the four-dimensional (4D) microstructure of cement paste can be captured, thereby assisting material scientists in studying the hydration process in situ. However, as a challenging task, the construction of high-quality 4D microstructural image is remarkably impeded by image size, isotropy, and homogeneity. This paper proposes an image processing framework to construct 4D high quality microstructural image rapidly for cement hydration. This framework improves and accelerates microstructural image registration and enhancement by using bias field correction, temporal intensity calibration and fast image registration. Additionally, a partial information registration method adopting partial information on the spatial and phased scales, is proposed to improve the registration speed and accuracy. Furthermore, a multi-factor multi-layer particle swarm optimization is proposed to improve the optimization in registration. Experimental results indicate that the 4D high quality microstructural image can be constructed rapidly with promising precision.

Ceramic Biomaterial Pores Stereology Analysis by the Use of Microtomography.

The main aim of this study was to analyze microtomographic data to determine the geometric dimensions of a ceramic porous material’s internal structure. Samples of a porous corundum biomaterial were the research material. The samples were prepared by chemical foaming and were measured using an X-ray scanner. In the next stage, 3D images of the samples were generated and analyzed using Thermo Scientific Avizo software. The analysis enabled the isolation of individual pores. Then, the parameters characterizing the pore geometry and the porosity of the samples were calculated. The last part of the research consisted of verifying the developed method by comparing the obtained results with the parameters obtained from the microscopic examinations of the biomaterial. The comparison of the results confirmed the correctness of the developed method. The developed methodology can be used to analyze biomaterial samples to assess the geometric dimensions of biomaterial pores.

Discussion on ‘Utilization of X-ray computed micro-tomography to evaluate iron sulphide distribution in roofing slates’: Quarterly Journal of Engineering Geology and Hydrogeology , Vol. 51, 2018, pp. 169–178

The paper presented by Vavro et al . (2018) is an interesting application of a relatively new technique, X-ray computed micro-tomography (MCT), for the determination of iron sulphides in roofing slates. Once the slate shingles are installed on a roof, these iron sulphides may oxidize, creating unattractive red stains running along the roof surface. This pathology is considered to be the main technical problem for the roofing slate industry (Cardenes et al . 2016 a ). In their paper, Vavro et al . (2018) explain how the use of MCT allows quantification of the amount, size and spatial distribution of the iron sulphides on two samples of roofing slates. However, their work misses some important …

PHYSICAL INTERPRETATION OF NEURON TRAINING IN FUZZY CLUSTERING NETWORKS WHEN USING MICROTOMOGRAPHY IN MEDICAL AND BIOLOGICAL RESEARCH

The physical bases and interpretation of the procedure for training neurons in the fuzzy cellular neural networks of Kohonen have been investigated. Based on them, the method of automatic calibration of digital X-ray microtomographs has been described. This method involves neural-fuzzy segmentation of a distorted image into a finite number of clusters. The method is of great practical importance for the use of microtomography in biomedical research.

100-million-year-old conifer tissues from the mid-Cretaceous amber of Charente (western France) revealed by synchrotron microtomography.

Terrestrial plant remains in fossilized tree resin are relatively common. However, histology and preservation of plants entombed in Cretaceous ambers remain poorly known. We report an exquisitely preserved conifer leafy axis from 100-million-year-old opaque amber of western France that is assignable to Glenrosa carentonensis Moreau, Néraudeau, Tafforeau & Dépré. The purpose of this paper is to discuss the taphonomy and the use of microtomography for studies of palaeobotanical remains in amber. A leafy axis was examined using propagation phase-contrast X-ray synchrotron microtomography with voxel sizes of 14·9, 1·4, and 0·7 μm. The conifer leafy axis described is preserved in three dimensions. Despite desiccation of the specimen within the surrounding amber, the cuticle, as well as most of inner tissues, is preserved in three dimensions down to the cellular level. Epidermis, palisade parenchyma, spongy parenchyma, transfusion tracheids and vascular bundles are clearly distinguished. Gross morphology and histology of the specimen were revealed using synchrotron microtomography, allowing an unprecedented resolution for the study of soft-bodied plants entombed in amber. The study reveals a peculiar combination of authigenic and duripartic preservation as well as permineralization, and highlights the complexity of taphonomic processes that can occur in amber inclusions. This fossil demonstrates the difficulty of studying amber-preserved plant remains under certain conditions.

Use of micro-tomography for validation of method to identify interfacial shear strength from tensile tests of short regenerated cellulose fibre composites

The interfacial shear strength of short regenerated cellulose fibre/polylactide composites was characterized by means of an industry-friendly adhesion test method. The interfacial shear strength was back-calculated from the experimental tensile stress-strain curves of composites by using a micro-mechanical model. The parameters characterizing the microstructure of the composites, e.g. fibre length and orientation distributions, used as input in the model were obtained by micro-tomography. The investigation was carried out on composites with untreated and surface treated fibres with various fibre weight contents (5wt%, 10wt%, and 15wt% for untreated fibres, and 15wt% for treated fibres). The properties of fibres were measured by an automated single fibre tensile test method. Based on these results, the efficiency of the fibre treatment to improve fibre/matrix adhesion is evaluated, and the applicability of the method to measure the interfacial shear strength is discussed. The results are compared with data from previous work, and with other results from the literature.

The use of microtomography in structural geology: A new methodology to analyse fault faces

This paper describes a new methodology to kinematically analyze faults in microscale dimensions (voxel size = 40 μm), using images obtained by X-ray computed microtomography (μCT). The equipment used is a GE MS8x-130 scanner. It was developed using rocks samples from Santa Catarina State, Brazil, and constructing micro Digital Elevation Models (μDEMs) for the fault surface, for analysing microscale brittle structures including striations, roughness and steps. Shaded relief images were created for the μDEMs, which enabled the generation of profiles to classify the secondary structures associated with the main fault surface. In the case of a sample with mineral growth that covers the fault surface, it is possible to detect the kinematic geometry even with the mineral cover. This technique proved to be useful for determining the sense of movement of faults, especially when it is not possible to determine striations in macro or microscopic analysis. When the sample has mineral deposit on the surface (mineral cover) this technique allows a relative chronology and geometric characterization between the faults with and without covering.

Investigation of Pore-Scale Mixed Wettability

Summary The efficiency of secondary and tertiary-recovery processes can be improved by properly taking into account the reservoir's true wettability state. Most reservoirs are assumed to be mixed-wet, based on core-scale indices such as Amott-Harvey and USBM. Oil/brine/ mineral contact-angle measurements on smooth substrates offer some molecular-scale input and estimates for network modeling. However, direct experimental techniques to characterize wettability and validate the mixed-wet model at the pore scale in real or model rocks remain elusive. One promising avenue is the use of microtomography (µ-CT) to map the pore-scale distribution of multiple phases in miniplugs. A second, complementary approach involves the study of model rocks based on bead packs to probe the surface chemistry of the minerals exposed to crude oil and brine in pore confinement. Integrating the two approaches described in the current study provides a promising means of explaining the observed multiphase-fluid occupancy in pores by combining the detailed knowledge of the 3D pore structure and information on the surface chemistry of its walls.

Optimal removal of topological artefacts in microtomographic images of porous materials

The analysis of flow at the pore scale in porous media has been facilitated with the use of microtomography. A powerful tool for quantifying the fluid structure using these tomographic 3D reconstructions is skeletonisation, but the significant disadvantage of this method is its sensitivity to noise, resulting in artefacts in the skeleton. A pre-processing of the 3D image is therefore required, but no method has yet proven to completely solve this problem. By developing a new procedure that, by construction, directly identifies the voxels and only those that are responsible for topological artefacts in the skeleton, we are able to remove all artefacts, and furthermore can prove that we do so by modifying a minimal amount of voxels in the segmented 3D image (i.e. the tomographic image in which each voxel has been assigned to either the porous or the solid phase). This is possible by identifying the three fundamental types of artefacts that can arise in a 3D skeleton, and dealing with each appropriately. Application to a microtomographic image of a sintered glass powder is presented. Impact of the different processing methods on the flow within its porosity is measured through the computed permeability deviations.

Description and molecular phylogeny of Tethya leysae sp. nov. (Porifera, Demospongiae, Hadromerida) from the Canadian Northeast Pacific with remarks on the use of microtomography in sponge taxonomy

Description and molecular phylogeny of Tethya leysae sp. nov. (Porifera, Demospongiae, Hadromerida) from the Canadian Northeast Pacific with remarks on the use of microtomography in sponge taxonomy

Description and molecular phylogeny of Tethya leysae sp. nov. (Porifera, Demospongiae, Hadromerida) from the Canadian Northeast Pacific with remarks on the use of microtomography in sponge taxonomy

The sponge Tethya leysae sp. nov. (Porifera, Demospongiae, Hadromerida, Tethyidae) is a new species from the Canadian Northeast Pacific. Its type locality is the infralittoral around Ohiat Islet, Barkely Sound, Vancouver Island in Canada. Tethya leysae sp. nov. is a medium-sized spherical sponge with a verrucose surface, orange-yellow to light red alive and white with a greyish core in ethanol. The highly variable oxyspherasters (25-115 µm in size, R/C 0.34-0.69) are densely scattered almost throughout the entire cortex. The micrasters comprise acanthoxyspherasters, acanthostrongylasters, acanthotylasters and small oxyspherasters, which are present at low densities throughout the sponge and form a dense layer associated with the exopinacoderm. The megascleres and the auxiliary megascleres comprise oxeas and strongyloxeas. The new species is clearly distinguishable from the closely related T. californiana by the absence of spherules among the micrasters, the lack of an alveolar cortex and the extremely high density of megasters in the cortex. In addition, the R/C values of the megasters differ between the two species and the oxyspherasters of T. leysae sp. nov. rarely display bent rays. The morphological differences between the species are confirmed by nucleotide and amino acid substitutions within the cytochrome oxidase subunit I (COI) mtDNA gene. Phylogenetic analyses group T. leysae sp. nov. with T. californiana, T. actinia and T. minuta, which together form a sister group to a MediterraneanNorth Atlantic species cluster. Morphological analyses of the skeleton included x-ray microtomography (µCT) and virtual 3D reconstruction, which was used for the first time in conjunction with the description of a new sponge species. Microtomography permitted the visualization and analysis of spicules within the skeletal context or isolated in silico. The method represents a valuable extension to the sponge taxonomist’s toolbox since it allows morphometric measurements in 3D. µCT will thus supplement classical morphological methods such as light and scanning electron microscopy.

Renal calculi composition studies with the use of microtomography

Renal calculi composition studies with the use of microtomography

In SituX-Ray Tomography Measurements of Deformation in Cellular Solids

AbstractThe use of microtomography to study the structure and especially the deformation modes of cellular solids is reviewed in this article. First, the technique is described in detail. Examples illustrating the power of the coupling ofin situdeformation with three-dimensional (3D) imaging, drawn from the recent literature and the authors' own work, are then given. The most detailed example is the study of the deformation modes of several samples made of different aluminum foams. Four kinds of closed-cell foams were investigated, corresponding to different routes available today for their manufacture. The initial macrostructure was quantified using the 3D images combined with 3D granulometry, allowing retrieval of pertinent information about the cell size and the wall and strut thicknesses. The global behavior exhibited by the foams during thein situcompression experiments was shown to vary from one brand of material to another. Some of these variations can be explained by differences in the known microstructure and the measured macrostructure of the samples.