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Abstract: Background: Barrett’s dysplasia confers significantly greater risk of developing oesophageal adenocarcinoma (OAC) which has poor outcomes. Radiofrequency ablation (RFA) has become established therapy for Barrett’s dysplasia. Long-term data is lacking. Staging is the most accurate reflection of cancer prognosis. Accuracy of this staging is conflicting. I aim to establish if: I. outcomes from RFA are durable and reduce the risk of developing OAC II. T2N0 oesophageal cancer staging is accurate III. x-ray phase imaging (XPCI) can stage and grade oesophageal tissues / Methods: Analysis of the UK RFA registry was conducted to calculate rates of invasive cancer, clearance rates of dysplasia (CR-D) and intestinal metaplasia (CR-IM). Accuracy of oesophageal cancer staging was established using a systematic review. To grade and stage oesophageal tissues XPCI techniques were used. / Results: Ten-years after RFA therapy, cancer rate was 4.1%. CR-D and CR-IM after 2 years of therapy were 88% and 62.6%. Persistance rates were 5.9% from CR-D and 18.7% from CR-IM at 8 years, most recurrences occurred within 2 years.

Open Access

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Abstract: How pigment distribution influences the cuticle density within a microscopic butterfly wing scale, and how both impact each scale’s final reflected color, remains unknown. We use ptychographic X-ray computed tomography to quantitatively determine, at nanoscale resolutions, the three-dimensional mass density of scales with pigmentation differences. By comparing cuticle densities between two pairs of scales with pigmentation differences, we determine that the density of the lower lamina is inversely correlated with pigmentation. In the upper lamina structure of Junonia orithya and Bicyclus anynana, low pigment levels also correlate with sheet-like chitin structures as opposed to rod-like structures. Within each scale, we determine that the lower lamina in all scales has the highest density, and distinct layers within the lower lamina help explain reflected color. We hypothesize that pigments, in addition to absorbing specific wavelengths, can affect cuticle polymerization, density, and refractive index, thereby impacting reflected wavelengths that produce colors.

Open Access

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Abstract: X-ray ptychography is a robust microscopy technique with nanoscale resolution that requires a spatially and temporally coherent illumination. In a typical setup, the temporal coherence requirements are satisfied by monochromating the x-ray source, e.g., using a crystal monochromator. Recent studies have shown that energy resolving, or hyperspectral, detectors can to some extent replace the role of the monochromator to perform, e.g., edge-subtraction ptychographic imaging with broadband radiation in a single acquisition. Scaling this capability from two dimensions (2D) to three dimensions (3D), and from a single absorption edge to multiple edges, is critical for its applications in structural and elemental characterisation. The method is hitherto limited by the inherently lower maximum count rate of hyperspectral detectors and the chromaticity of the optics often used in x-ray ptychography experiments, namely Fresnel zone plates. In this work, we design an optimized broadband spectroscopic ptychography setup and use it to perform 3D hyperspectral imaging of particles of battery material containing various percentages of nickel, manganese, cobalt (NMC). We show that we can identify different compositions based on their spectral response. We discuss the results and provide guidelines for future exploitation of the method in laboratory settings.

Open Access

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Abstract: The choice of fixative is critical in X-ray phase-contrast tomography (XPCT) because it affects tissue preservation, contrast enhancement and compatibility with other imaging techniques. A careful selection and optimization of fixatives can lead to significant improvements in the quality and accuracy of imaging results, which is especially important when studying complex biological systems such as those involved in neurodegeneration, where it is crucial to maintain the fine details of the Grey Matter (GM) and White Matter (WM) structures. Dehydration with ethanol and xylene is commonly used as it effectively removes water while minimising structural alterations. Using perfusion in ethanol and dehydration in xylene as a secondary fixative can increase the contrast, thereby improving the visibility of myelinated fibers without using a contrast agent. In this paper we discuss an optimised fixation method to significantly enhance the contrast and boost the signal to noise ratio (SNR) in XPCT images of WM in the central nervous system (CNS).

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Abstract: The performance and longevity of lithium-ion batteries depend critically on the structural and electrochemical dynamics of their constituent materials, particularly cathodes. Among these, LiCoO2 (LCO) is a benchmark material known for its high energy density. However, the structural evolution of LCO during electrochemical cycling, including strain, defects, and domain formation, remains poorly understood, largely due to the limitations of conventional imaging techniques in resolving nanoscale dynamics non-destructively. This thesis leverages Bragg Coherent X-ray Diffraction Imaging (Bragg CDI), a powerful, non-destructive technique, to probe the three-dimensional structural and strain dynamics of nanocrystalline LCO cathodes. By combining traditional phasing methods with machine learning-based strain reconstruction tools, and further enhancing data interpretation with advanced analysis techniques, this work provides unprecedented insights into the nanoscale behaviour of LCO under varying electrochemical and electric field conditions. The study reveals that during electrochemical cycling, LCO nanocrystals exhibit dynamic domain behaviour, including the formation and expansion of domains at the crystal edges in the charged state, followed by fragmentation into smaller domains bounded by dislocations. These processes are reversed during discharge, with domains shrinking and reassembling as the crystal approaches its discharged state. Additionally, under applied electric fields, polarised domains and significant phase changes are observed, with the field inducing phase uniformity along its direction. Notably, a migrating dislocation near the crystal edge exhibits depth invariance across varying field magnitudes, aligning with the domain expansion limit observed during cycling. These findings contribute to a deeper understanding of the structural and electrochemical interplay in LCO cathodes, offering valuable insights into the mechanisms underlying performance degradation and suggesting pathways for improving battery design and functionality.