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T. Weitkamp

Publications and source records attributed to T. Weitkamp.

3 recordsLinked to original sources

Micro and Nano 3D investigation of complex gut alterations-dementia interplay

Alzheimer's disease (AD), a debilitating neurodegenerative disorder, remains one of the foremost public health challenges of our time. Despite decades of research, its etiology largely remains enigmatic. Recently, attention has turned to the gut-brain axis, a complex network of communication between the gastrointestinal tract and the brain, as a potential player in the pathogenesis of AD. Here we exploited X-ray Phase Contrast Tomography to provide an in-depth analysis of the link between the gut condition and AD, exploring gut anatomy and structure in murine models. We conducted a comprehensive analysis by comparing the outcomes in various mouse models of cognitive impairment, including AD, frail mice, and frontotemporal dementia (FTD) affected mice. We discovered an association between substantial changes in the gut structure and the presence of amyloid-beta (A\b{eta}) in the brain. We found that the most important gut alterations are related to A\b{eta} occurrence in the brain. In particular, we investigated the gut morphology, the distribution of enteric micro-processes and neurons in the ileum. Understanding the intricate interplay between gut condition and dementia may open new avenues for early AD diagnosis and treatment offering hope for a future where these diseases may be more effectively addressed.

physics.app-ph

Microtomography on the ANATOMIX beamline at Synchrotron SOLEIL

The ANATOMIX beamline at Synchrotron SOLEIL, operational since 2018, is dedicated to hard X-ray full-field tomography techniques. Operating in a range of photon energies from approximately 5 to 50 keV, it offers both parallel-beam projection microtomography, in absorption and phase contrast, and nanotomography using a zone-plate transmission X-ray microscope. With these methods, the beamline covers a range of spatial resolution from 20 nm to 20 $\mu$m, expressed in terms of useful pixel size. The variable beam size of up to 40 mm allows users to image large objects. Here we describe the microtomography instrumentation of the beamline.

physics.ins-det

X-ray microtomography of heavy microstructures: the case of Plasma-Sprayed Tungsten and Tungsten-Steel MMC

In this paper synchrotron microtomography on Plasma Sprayed Tungsten (PS-W) is presented and discussed. PS-W is a challenging material for microtomography since it exhibits a random porous network at different length-scales (from nanometers to micrometers) and is hardly penetrable by X-rays. Furthermore, inner porosity causes strong internal scattering. The key challenges were, firstly, to optimize the beam parameters considering the inherent trade-off between photon energy (penetration depth) and spatial resolution and, secondly, to develop effective signal filtering algorithms. Despite the limited signal-to-noise ratio detected, large volumes of PS-W could be reconstructed with good image quality and micrometric resolution (voxel size = 1.4 μm). As an important result, we report excellent image quality and higher penetration depth by applying the same setup on a ferrous microstructure, namely a 10%W/Steel MMC used as interlayer between PS-W and a ferritic/martensitic steel substrate. The paper reports a detailed 3D morphological analysis of all inclusion types in PS-W and W/Steel, which led to disclosure of a complex connected porous network in both media. The analysis is presented in terms of multiphase volume fraction, ratio of percolation and 3D shape descriptors. 3D percolation patterns are analyzed in detail and sensitivity towards segmentation threshold for the noise-affected PS-W region is discussed. Remarkably, percolation of the porous phase was found throughout the entire coating thickness of PS-W. In W-Steel MMC percolation was found in the perpendicular plane and interpreted as onset of delamination caused by thermomechanical stress.

cond-mat.mtrl-sci