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Instruments / Technical Area	Publication Details	Published
I13-2-Diamond Manchester Imaging	Time-lapse in situ 3D imaging analysis of human enamel demineralisation using X-ray synchrotron tomography Cyril Besnard , Ali Marie , Sisini Sasidharan , Robert A. Harper , Shashidhara Marathe , Jonathan Moffat , Richard M. Shelton , Gabriel Landini , Alexander M. Korsunsky Dentistry Journal 11 DOI: 10.3390/dj11050130 Diamond Proposal Number(s): [25756] Open Access Show Abstract ▼ Abstract: Caries is a chronic disease that causes the alteration of the structure of dental tissues by acid dissolution (in enamel, dentine and cementum) and proteolytic degradation (dentine and cementum) and generates an important cost of care. There is a need to visualise and characterise the acid dissolution process on enamel due to its hierarchical structure leading to complex structural modifications. The process starts at the enamel surface and progresses into depth, which necessitates the study of the internal enamel structure. Artificial demineralisation is usually employed to simulate the process experimentally. In the present study, the demineralisation of human enamel was studied using surface analysis carried out with atomic force microscopy as well as 3D internal analysis using synchrotron X-ray tomography during acid exposure with repeated scans to generate a time-lapse visualisation sequence. Two-dimensional analysis from projections and virtual slices and 3D analysis of the enamel mass provided details of tissue changes at the level of the rods and inter-rod substance. In addition to the visualisation of structural modifications, the rate of dissolution was determined, which demonstrated the feasibility and usefulness of these techniques. The temporal analysis of enamel demineralisation is not limited to dissolution and can be applied to other experimental conditions for the analysis of treated enamel or remineralisation.	May 2023
I08-Scanning X-ray Microscopy beamline (SXM) I14-Hard X-ray Nanoprobe	Nanoscale correlative X-ray spectroscopy and ptychography of carious dental enamel Cyril Besnard , Ali Marie , Sisini Sasidharan , Petr Buček , Jessica Walker , Julia E. Parker , Thomas E. J. Moxham , Benedikt Daurer , Burkhard Kaulich , Majid Kazemian , Richard M. Shelton , Gabriel Landini , Alexander M. Korsunsky Materials & Design 375 DOI: 10.1016/j.matdes.2022.111272 Diamond Proposal Number(s): [30684, 31005] Open Access Show Abstract ▼ Abstract: This study reports the characterisation of human dental enamel caries using synchrotron nanoscale correlative ptychography and spectroscopic mapping in combination with scanning electron microscopy. A lamella ̴2.4 µm thick was extracted from a carious enamel region of a tooth using focused ion beam-scanning electron microscopy and transferred to two synchrotron beamlines to perform hard X-ray nano-fluorescence spectroscopy simultaneously with differential phase contrast mapping at a beam size of 50 nm. Soft X-ray ptychography data was then reconstructed with a pixel size of 8 nm. The two dimensional variation in chemistry and structure of carious enamel was revealed at the nanoscale, namely, the organisation of hydroxyapatite nano-crystals within enamel rods was imaged together with the inter-rod region. Correlative use of electron and X-ray scanning microscopies for the same sample allowed visualisation of the connection between structure and composition as presented in a compound image where colour indicates the relative calcium concentration in the sample, as indicated by the calcium Kα fluorescence intensity and grey scale shows the nanostructure. This highlights the importance of advanced correlative imaging to investigate the complex structure-composition relationships in nanomaterials of natural or artificial origin.	Oct 2022
E01-JEM ARM 200CF I13-2-Diamond Manchester Imaging	Hierarchical 2D to 3D micro/nano-histology of human dental caries lesions using light, X-ray and electron microscopy Cyril Besnard , Ali Marie , Petr Buček , Sisini Sasidharan , Robert A. Harper , Shashidhara Marathe , Kaz Wanelik , Gabriel Landini , Richard M. Shelton , Alexander Korsunsky Materials & Design 394 DOI: 10.1016/j.matdes.2022.110829 Diamond Proposal Number(s): [29256, 30666] Open Access Show Abstract ▼ Abstract: Dental caries is a widespread disease that damages teeth by heterogeneous dissolution. Conventional histology identifies different zones within carious lesions by their optical appearance, but fails to quantify the underlying nanoscale structural changes as a function of specific location, impeding better understanding of the demineralisation process. We employ detailed collocative analysis using different imaging modalities, resolutions and fields of view. Focused ion beam-scanning electron microscopy (FIB-SEM) reveals subsurface 3D nanostructure within milled micro-sized volumes, whilst X-ray tomography allows less destructive 3D imaging over large volumes. Correlative combination of these techniques reveals fine detail of enamel rods, inter-rod substance, sheaths, crystallites and voids as a function of location. The degree of enamel demineralisation within the body of the lesion, near its front, and at the surface is visualized in 3D. We thus establish the paradigm of dental 3D nano-histology as an advanced platform for quantitative evaluation of caries-induced structural modification.	Jun 2022
I13-2-Diamond Manchester Imaging	3D analysis of enamel demineralisation in human dental caries using high-resolution, large field of view synchrotron X-ray micro-computed tomography Cyril Besnard , Robert A. Harper , Thomas E. J. Moxham , Jonathan D. James , Malte Storm , Enrico Salvati , Gabriel Landini , Richard M. Shelton , Alexander M. Korsunsky Materials Today Communications 392 DOI: 10.1016/j.mtcomm.2021.102418 Diamond Proposal Number(s): [20479] Open Access Show Abstract ▼ Abstract: We report major advances in the analysis of synchrotron 3D datasets acquired from human healthy and carious dental enamel. Synchrotron tomographic data for three human carious samples and a non-carious reference tooth sample were collected with the voxel size of 325 nm for a total volume of 815.4 × 815.4 × 685.4 μm3. The results were compared with conventional X-ray tomography, optical microscopy, and focused ion beam-scanning electron microscopy. Clear contrast was seen within demineralised enamel due to reduced mineral content using synchrotron tomography in comparison with conventional tomography. The features were found to correspond with the rod and inter-rod structures within prismatic enamel. 2D and 3D image segmentation allowed statistical quantification of important structural characteristics (such as the aspect ratio and the cross-sectional area of voids, as well as the demineralised volume fraction as a function of lesion depth). Whilst overall carious enamel predominantly displayed Type 1 etching pattern (preferential demineralisation of enamel rods), a transition between Type 2 (preferential inter-rod demineralisation) and Type 1 was identified within the same lesion for the first time. This study does not intend to give extensive results on the different lesions studied, but to illustrate a new method and its potential application.	May 2021
B16-Test Beamline	Analysis of in vitro demineralised human enamel using multi-scale correlative optical, scanning electron microscopy and high-resolution synchrotron wide-angle X-ray scattering Cyril Besnard , Robert A. Harper , Enrico Salvati , Thomas E. J. Moxham , Leon Romano Brandt , Gabriel Landini , Richard M. Shelton , Alexander M. Korsunsky Materials & Design DOI: 10.1016/j.matdes.2021.109739 Diamond Proposal Number(s): [19192] Open Access Show Abstract ▼ Abstract: Enamel caries is a highly prevalent disease that involves demineralisation of the enamel structure. In this study, we report the analysis of artificially demineralised human enamel slices etched using lactic acid (2 % v/v) in comparison with healthy enamel using correlative techniques of optical and electron microscopy, as well as scanning diffraction. Demineralisation of the enamel was characterised within the micron to sub-micron scale. The structure of the healthy enamel was investigated using focused ion beam - scanning electron microscopy (FIB-SEM) and compared with an etched sample to reveal structural differences. Additional chemical analysis using energy-dispersive X-ray spectroscopy (EDS) was performed and a decrease in the Ca/P atomic % ratio was found in etched samples in comparison with healthy enamel, suggesting more loss of calcium compared with phosphorus. Synchrotron wide-angle X-ray scattering (WAXS) was performed on the samples to reveal the differences in the diffraction patterns before and after etching in terms of lattice structure and preferred orientation (texture). Texture maps were extracted from diffraction analysis at 500 nm spatial resolution. These maps were correlated with the dimension of the enamel structure. The multi-scale correlative approach provided insights into the demineralisation-induced enamel structure alteration at a resolution approaching 500 nm.	Apr 2021
I13-2-Diamond Manchester Imaging	Finite element modelling and experimental validation of enamel demineralisation at the rod level Enrico Salvati , Cyril Besnard , Robert A. Harper , Thomas Moxham , Richard M. Shelton , Gabriel Landini , Alexander M. Korsunsky Journal Of Advanced Research DOI: 10.1016/j.jare.2020.08.018 Open Access Show Abstract ▼ Abstract: In the past years, a significant amount of effort has been directed at the observation and characterisation of caries using experimental techniques. Nevertheless, relatively little progress has been made in numerical modelling of the underlying demineralisation process. The present study is the first attempt to provide a simplified calculation framework for simulating the demineralisation process at the length scale of enamel rods and its validation by comparing the data with statistical analysis of synchrotron X-ray CT results. The local orientation of the hydroxyapatite crystals is accounted to solve a time-dependent reaction-diffusion equation, in which H ions diffuse and demineralise the enamel. insights into the pH level of the etchant solution and origin of different etching morphology were obtained by simulating these processes through the newly developed model. The implications of this study itself pave the way for simulations of enamel demineralisation within different complex scenarios and higher length scales. Indeed, the framework proposed can incorporate the presence of chemical species other than H ions and their diffusion and reaction leading to dissolution and re-precipitation of hydroxyapatite. It is the authors’ hope and aspiration that ultimately this work will help identify new ways of controlling and preventing caries.	Sep 2020
B16-Test Beamline	Ovine bone morphology and deformation analysis using synchrotron X-ray imaging and scattering Eugene S. Statnik , Alexey I. Salimon , Cyril Besnard , Jingwei Chen , Zifan Wang , Thomas Moxham , Igor P. Dolbnya , Alexander Korsunsky Quantum Beam Science 4 DOI: 10.3390/qubs4030029 Diamond Proposal Number(s): [21419] Open Access Show Abstract ▼ Abstract: Bone is a natural hierarchical composite tissue incorporating hard mineral nano-crystals of hydroxyapatite (HAp) and organic binding material containing elastic collagen fibers. In the study, we investigated the structure and deformation of ovine bone by the combination of high-energy synchrotron X-ray tomographic imaging and scattering. X-ray experiments were performed prior to and under three-point bending loading by using a specially developed in situ load cell constructed from aluminium alloy frame, fast-drying epoxy resin for sample fixation, and a titanium bolt for contact loading. Firstly, multiple radiographic projection images were acquired and tomographic reconstruction was performed using SAVU software, following segmentation using Avizo. Secondly, Wide Angle X-ray Scattering (WAXS) and Small Angle X-ray Scattering (SAXS) 2D scattering patterns were collected from HAp and collagen. Both sample shape and deformation affect the observed scattering. Novel combined tomographic and diffraction analysis presented below paves the way for advanced characterization of complex shape samples using the Dual Imaging and Diffraction (DIAD) paradigm.	Aug 2020
B16-Test Beamline I13-1-Coherence	Synchrotron X-ray quantitative evaluation of transient deformation and damage phenomena in a single Nickel-rich cathode particle Leon Romano Brandt , John-Joseph Marie , Thomas Moxham , Dominic P. Forstermann , Enrico Salvati , Cyril Besnard , Chrysanthi Papadaki , Zifan Wang , Peter G. Bruce , Alexander Korsunsky Energy & Environmental Science DOI: 10.1039/D0EE02290J Diamond Proposal Number(s): [22503, 22217] Open Access Show Abstract ▼ Abstract: The performance and durability of Ni-rich cathode materials are controlled in no small part by their mechanical durability, as chemomechanical breakdown at the nano-scale leads to increased internal resistance and decreased storage capacity. The mechanical degradation is caused by the transient lithium diffusion processes during charge and discharge of layered oxide spherical cathode micro-particles, leading to highly anisotropic incompatible strain fields. Experimental characterisation of the transient mechanisms underlying crack and void formation requires the combination of very high resolution in space (sub-micron) and time (sub-second) domains without charge interruption. The present study is focused on sub-micron focused operando synchrotron X-ray diffraction and in situ Ptycho-Tomographic nano-scale imaging of a single nano-structured LiNi0.8Co0.1Mn0.1O2 core-shell particle during charge to obtain a thorough understanding of the anisotropic deformation and damage phenomena at a particle level. Preferential grain orientation within the shell of a spherical secondary cathode particle provides improved lithium transport but is also associated with spatially varying anisotropic expansion of the hexagonal unit cell in the c-axis and contraction in the a-axis. These effects were resolved in relation to the grain orientation, and the link established with the nucleation and growth of intergranular cracks and voids that causes electrical isolation of active cathode material. Coupled multi-physics Finite Element Modelling of diffusion and deformation inside a single cathode particle during charge and discharge was validated by comparison with experimental evidence and allowed unequivocal identification of key mechanical drivers underlying Li-ion battery degradation.	Aug 2020
B16-Test Beamline	Synchrotron X-ray scattering analysis of Nylon-12 crystallisation variation depending on 3D printing conditions Benjamin De Jager , Thomas Moxham , Cyril Besnard , Enrico Salvati , Jingwei Chen , Igor P. Dolbnya , Alexander M. Korsunsky Polymers 12 DOI: 10.3390/polym12051169 Diamond Proposal Number(s): [20428, 24513] Open Access Show Abstract ▼ Abstract: Nylon-12 is an important structural polymer in wide use in the form of fibres and bulk structures. Fused filament fabrication (FFF) is an extrusion-based additive manufacturing (AM) method for rapid prototyping and final product manufacturing of thermoplastic polymer objects. The resultant microstructure of FFF-produced samples is strongly affected by the cooling rates and thermal gradients experienced across the part. The crystallisation behaviour during cooling and solidification influences the micro- and nano-structure, and deserves detailed investigation. A commercial Nylon-12 filament and FFF-produced Nylon-12 parts were studied by differential scanning calorimetry (DSC) and wide-angle X-ray scattering (WAXS) to examine the effect of cooling rates under non-isothermal crystallisation conditions on the microstructure and properties. Slower cooling rates caused more perfect crystallite formation, as well as alteration to the thermal properties.	May 2020
I05-ARPES	Bulk and surface electronic structure of the dual-topology semimetal Pt2HgSe3 I. Cucchi , A. Marrazzo , E. Cappelli , S. Ricco , F. Y. Bruno , S. Lisi , M. Hoesch , T. K. Kim , C. Cacho , C. Besnard , E. Giannini , N. Marzari , M. Gibertini , F. Baumberger , A. Tamai Physical Review Letters 124 DOI: 10.1103/PhysRevLett.124.106402 Diamond Proposal Number(s): [18952] Show Abstract ▼ Abstract: We report high-resolution angle-resolved photoemission measurements on single crystals of Pt 2 HgSe 3 grown by high-pressure synthesis. Our data reveal a gapped Dirac nodal line whose (001) projection separates the surface Brillouin zone in topological and trivial areas. In the nontrivial k -space range, we find surface states with multiple saddle points in the dispersion, resulting in two van Hove singularities in the surface density of states. Based on density-functional theory calculations, we identify these surface states as signatures of a topological crystalline state, which coexists with a weak topological phase.	Feb 2020

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