No abstract

When a very low absorbing sample is scanned at an X-ray CT-setup with a microfocus X-ray tube and a high resolution detector, the obtained projection images not only contain absorption contrast, but also phase contrast. While images without a phase signal can be reconstructed very well, such mixed phase and absorption images give rise to severe artefacts in the reconstructed slices. In this paper, a method is described that applies a correction to these mixed projections, in order to remove the phase signal. These corrected images can then be processed using a standard filtered back projection algorithm to obtain reconstructions with only little or no phase artefacts. This new method, which we call the Bronnikov Aided Correction (BAC), can be used in a broad variety of applications and without much additional effort. It is tested on a biological and a pharmaceutical sample, results are evaluated and discussed by comparing them with conventional reconstruction methods.

In this work, we present a novel laboratory-based micro-computed tomography (micro-CT) experiment designed to investigate the pore scale drainage behavior of natural sandstone under dynamic conditions. The fluid distribution in a Bentheimer sandstone was visualized every 4 seconds with a 12 second measurement time, allowing the investigation of single- and few-pore filling events. To our knowledge, this is the first time that such measurements were performed outside of synchrotron facilities, illustrating the growing application potential of lab-based micro-CT with sub-minute temporal resolutions for geological research at the pore scale. To illustrate how the workflow can lead to an improved understanding of drainage behavior, the experiment was analyzed using a decomposition of the pore space into individual geometrical pores. Preliminary results from this analysis suggest that the distribution of drainage event sizes follows a power law scaling, as expected from percolation theory

A novel technique based on micro-CT scanning is developed to quantify coagulation in fibers of hemodialyzers. This objectivation is needed to allow accurate assessment of thrombogenicity of dialyzers used during hemodialysis, for example when comparing different strategies to avoid coagulation and/or fiber blocking. The protocol allowed imaging at a resolution of 25 µm, making it possible to count the open, non-coagulated fibers in a non-invasive way. In 3 fresh, non-used FX600 hemodialyzers, patent fiber counts were extremely consistent (10748 ± 2). To illustrate the potential of this technique, different dialysis parameters currently used as surrogates for fiber blocking were evaluated during 20 hemodialysis sessions. After dialysis, the FX600 dialyzers were visually scored for clotting, dried and subsequently weighed and scanned. The number of patent fibers (10003 [8763,10330], range 534–10692) did not correlate with any of the recorded surrogate parameters. Micro-CT scanning is a feasible, objective, non-invasive, accurate and reproducible tool for quantification of the degree of fiber blocking in a hemodialyzer after use, making it a potential gold standard for use in studies on fiber blocking during renal replacement therapies.

Background Alterations in ambient temperature have been associated with multiple detrimental effects on broilers such as intestinal barrier disruption and dysbiosis resulting in systemic inflammation. Inflammation and 25-hydroxycholecalciferol (25-OH-D3) have shown to play a negative and positive role, respectively, in the regulation of bone mass. Hence the potential of 25-OH-D3 in alleviating heat induced bone alterations and its mechanisms was studied. Results Heat stress (HS) directly induced a decrease in tibia material properties and bone mass, as demonstrated by lower mineral content, and HS caused a notable increase in intestinal permeability. Treatment with dietary 25-OH-D3 reversed the HS-induced bone loss and barrier leak. Broilers suffering from HS exhibited dysbiosis and increased expression of inflammatory cytokines in the ileum and bone marrow, as well as increased osteoclast number and activity. The changes were prevented by dietary 25-OH-D3 administration. Specifically, dietary 25-OH-D3 addition decreased abundance of B- and T-cells in blood, and the expression of inflammatory cytokines, especially TNF-α, in both the ileum and bone marrow, but did not alter the diversity and population or composition of major bacterial phyla. With regard to bone remodeling, dietary 25-OH-D3 supplementation was linked to a decrease in serum C-terminal cross-linked telopeptide of type I collagen reflecting bone resorption and a concomitant decrement in osteoclast-specific marker genes expression (e.g. cathepsin K), whereas it did not apparently change serum bone formation markers during HS. Conclusions These data underscore the damage of HS to intestinal integrity and bone health, as well as that dietary 25-OH-D3 supplementation was identified as a potential therapy for preventing these adverse effects.