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X-ray phase-contrast imaging is an effective approach to drastically increase the contrast and sensitivity of microtomographic techniques. Numerous approaches to depict the real part of the complex-valued refractive index of a specimen are nowadays available. A comparative study using experimental data from grating-based interferometry and propagation-based phase contrast combined with single-distance phase retrieval applied to a non-homogeneous sample is presented (acquired at beamline ID19-ESRF). It is shown that grating-based interferometry can handle density gradients in a superior manner. The study underlines the complementarity of the two techniques for practical applications. [ABSTRACT FROM AUTHOR]

Synchrotron real-time radioscopy and in situ microtomography are the only techniques providing direct visible information on a micrometre scale of local deformation in the implant-abutment connection (IAC) during and after cyclic loading. The microgap formation at the IAC has been subject to a number of studies as it has been proposed to be associated with long-term implant success. The next step in this scientific development is to focus on the in situ fatigue procedure of two-component dental implants. Therefore, an apparatus has been developed which is optimized for the in situ fatigue analysis of dental implants. This report demonstrates both the capability of in situ radioscopy and microtomography at the ID19 beamline for the study of cyclic deformation in dental implants. The first results show that it is possible to visualize fatigue loading of dental implants in real-time radioscopy in addition to the in situ fatigue tomography. For the latter, in situ microtomography is applied during the cyclic loading cycles in order to visualize the opening of the IAC microgap. These results concur with previous ex situ studies on similar systems. The setup allows for easily increasing the bending force, to simulate different chewing situations, and is, therefore, a versatile tool for examining the fatigue processes of dental implants and possibly other specimens. [ABSTRACT FROM AUTHOR]

The purpose of this study was to describe a refined method using high-resolution synchrotron radiation microtomography (SRmicro-CT) to evaluate osseointegration and peri-implant bone volume fraction after titanium dental implant insertion. SRmicro-CT is considered gold standard evaluating bone microarchitecture. Its high resolution, high contrast, and excellent high signal-to-noise-ratio all contribute to the highest spatial resolutions achievable today. Using SRmicro-CT at a voxel size of 5 μm in an experimental goat mandible model, the peri-implant bone volume fraction was found to quickly increase to 50% as the radial distance from the implant surface increased, and levelled out to approximately 80% at a distance of 400 μm. This method has been successful in depicting the bone and cavities in three dimensions thereby enabling us to give a more precise answer to the fraction of the bone-to-implant contact compared to previous methods. [ABSTRACT FROM AUTHOR]

The application of synchrotron radiation X-ray computed micro-tomography (SR X-μCT) as a non-invasive approach to the microstructural investigation of Portland cement binders during hydration is presented. The two- and three-dimensional µm-scale imaging of undisturbed samples at hydration ages from ~1.5 h to 3 days is used to obtain a direct visualization of the spatial and temporal relationships between different cement paste components. The microstructural evolution of two cementitious systems during the early stages of hydration is successfully monitored from the comparison of tomographic slices and volumes, clearly showing the progressive growth of hydration phases; the changes in the amount of porosity and unreacted clinker are also quantified. Some critical issues related to the experimental setup and data processing are addressed and discussed as well. Furthermore, a simple procedure to estimate the mean X-ray absorption coefficient of cement pastes from X-ray radiographs is illustrated. The results confirm the potentialities of synchrotron-based X-ray computed micro-tomography for the three-dimensional investigation of µm-scale modifications in hydrating cement pastes with an adequate time resolution, thus providing a real in-situ monitoring of the microstructural evolution of such complex materials. [ABSTRACT FROM AUTHOR]

The kinematics of the biting and chewing mouthparts of insects is a complex interaction of various components forming multiple jointed chains. The non-invasive technique of in vivo cineradiography by means of synchrotron radiation was employed to elucidate the motion cycles of the mouthparts in the cockroach Periplaneta americana. Digital X-ray footage sequences were used in order to calculate predefined angles and distances, each representing characteristic aspects of the movement pattern. We were able to analyze the interactions of the mouthpart components and to generate a functional model of maxillary movement by integrating kinematic results, morphological dissections and fluorescence microscopy. During the opening and closing cycles, which take about 450-500 ms on average, we found strong correlations between the measured maxillary and mandibular angles, indicating a strong neural coordination of these movements. This is manifested by strong antiphasic courses of the maxillae and the mandibles, antiphasic patterns of the rotation of the cardo about its basic articulation at the head and by the deflection between the cardo and stipes. In our functional model of the maxilla, its movement pattern is explained by the antagonistic activity of four adductor-promotor muscles and two abductor-remotor muscles. However, beyond the observed intersegmental and bilateral stereotypy, certain amounts of variation across subsequent cycles within a sequence were observed with respect to the degree of correlation between the various mouthparts, the maximum, minimum and time course of the angular movements. Although generally correlated with the movement pattern of the mandibles and the maxillary cardo-stipes complex, such plastic behaviour was especially observed in the maxillary palpi and the labium. [ABSTRACT FROM AUTHOR]

In Europe, there had previously been a series of synchrotron X-ray computed tomography (XCT) workshops, so-called "Beamline Jockey Days" workshops, organized by national synchrotron radiation facilities. In this virtual workshop, we shared the experience of beamline and computational scientists directly involved with operation, presenting the current pipeline for data acquisition and reconstruction at the XCT beamlines. The virtual workshop on "X-ray Tomography at Synchrotron Facilities: Pipeline for Data Acquisition and Reduction" was held February 22-26, 2021, hosted by Elettra Sincrotrone Trieste (Italy) and organized through a joint collaboration between the Advanced Light Source (USA), the Advanced Photon Source (USA), the Diamond Light Source (UK), the European Synchrotron Radiation Facility (France), and Elettra Sincrotrone Trieste (Italy). [Extracted from the article]

Combustion foaming of Al-Ti intermetallics was observed in-situ by X-ray radioscopy at the Technical University Berlin, Germany, and at the experimental station ID-19 of the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. The acquisition rates were 6.7 fps and up to 500 fps, respectively. This allowed for observing in detail the internal structure development during combustion foaming of extruded Al-Ti powder compacts made with Al/Ti molar ratios of 3, 4 and 7 and containing 10 and 20 vol.% exothermic agent (Ti + B4C). At the beginning of the foaming process, μm-sized pores were observed. Foam shrinkage and pore coarsening started immediately after the combustion process. Specimens made with an Al/Ti ratio = 7 showed pore coarsening and a longer solidification time. Specimens with 10 vol.% exothermic agent experienced less volume expansion and pore coarsening than specimens with 20 vol.% exothermic agent. The specimens with an Al/Ti ratio = 4 contained fewer micropores than the one with an Al/Ti ratio = 3. [ABSTRACT FROM AUTHOR]

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