Browsing by Author "Arnold, Emily"
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Item Open Access 3D printing, the future of cost effective biomechanical testing(SAFE, 2017-04-06) Franceskides, C.; Arnold, Emily; Horsfall, Ian; Clasper, J.; Tozzi, G.; Zioupos, PeterItem Open Access Age related changes of rib cortical bone matrix and the application to forensicage-at-death estimation(Nature Publishing Group, 2021-01-22) Bonicelli, Andrea; Zioupos, Peter; Arnold, Emily; Rogers, Keith D.; Xhemali, Bledar; Kranioti, Elena F.Forensic anthropology includes, amongst other applications, the positive identification of unknown human skeletal remains. The first step in this process is an assessment of the biological profile, that is: sex, age, stature and ancestry. In forensic contexts, age estimation is one of the main challenges in the process of identification. Recently established admissibility criteria are driving researchers towards standardisation of methodological procedures. Despite these changes, experience still plays a central role in anthropological examinations. In order to avoid this issue, age estimation procedures (i) must be presented to the scientific community and published in peer reviewed journals, (ii) accurately explained in terms of procedure and (iii) present clear information about the accuracy of the estimation and possible error rates. In order to fulfil all these requirements, a number of methods based on physiological processes which result in biochemical changes in various tissue structures at the molecular level, such as modifications in DNA-methylation and telomere shortening, racemization of proteins and stable isotopes analysis, have been developed. The current work proposes a new systematic approach in age estimation based on tracing physicochemical and mechanical degeneration of the rib cortical bone matrix. This study used autopsy material from 113 rib specimens. A set of 33 parameters were measured by standard bio-mechanical (nanoindentation and microindentation), physical (TGA/DSC, XRD and FTIR) and histomorphometry (porosity-ImageJ) methods. Stepwise regressions were used to create equations that would produce the best ‘estimates of age at death’ vs real age of the cadavers. Five equations were produced; in the best of cases an equation counting 7 parameters had an R2 = 0.863 and mean absolute error of 4.64 years. The present method meets all the admissibility criteria previously described. Furthermore, the method is experience-independent and as such can be performed without previous expert knowledge of forensic anthropology and human anatomy.Item Open Access Assessing bone maturity: compositional and mechanical properties of rib cortical bone at different ages(Elsevier, 2021-11-27) Bonicelli, Andrea; Kranioti, Elena F.; Xhemali, Bledar; Arnold, Emily; Zioupos, PeterUnderstanding what maturity entails for bone, when it arrives, and its pre- and post-maturity traits and properties are very important for understanding its evolution and physiology. There is a clear but fine distinction between the chronological age of bone (the age of its donor) and the tissue age of the bone packets it comprises at the microscopic level. Whole bone fragility changes with age due to mass and architecture effects, but so do the properties of bone at the tissue level. Tissue age and tissue-level properties are therefore increasingly attracting a great deal of attention recently. The present study investigated compositional and material changes in the hydroxyapatite crystals, the collagenous phase, changes in bone matrix composition and its nanoindentation properties and their decline with chronological age in later life. The aim was to track the age threshold at which cortical bone arrives at maturity and what happens following that threshold. To do so FTIR, DSC/TGA, XRD, nanoindentation and microindentation were used to investigate rib cortical bone material across a cohort of 86 individuals from one ethnic group with age spanning between 17 and 82 years. Results of this cross-sectional study showed a clear increase in mineral content relative to the organic and water contents across all ages. Furthermore, an increase in crystal size and consequent decrease in strain (coherence length) was detected associated with secondary mineralisation and an increase in carbonate substitution. Overall, we observe a number of modifications which contribute to a typical functional behaviour of bone showing an increase in both indentation modulus and hardness until the age of about 35 after which both of these properties decline gradually and concomitantly to other physicochemical changes and seemingly until the end of one's life.Item Open Access Bone Disease: The Integration of Nano- and Macro-Scale Studies(Cranfield University, 2020-01-09 11:44) Arnold, EmilyBone is a hierarchical structure that provides support and protection to a body. In the macro-structure of bone, geometry affects it ability to perform these functions, while in the micro-structure the material properties dictate changes. The easy substitution of atoms into the crystal, as well as the binding of extraneous proteins to the surface, have been found to alter many material properties.This research aims to develop a greater understanding of the fundamental properties and behaviours of the mineral component of bone (biological Hydroxyapatite or HA) through several techniques, some that are well documented within the field of research and some that are not. While X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) are often used in the study of HAp, this research aims to expand the lesser-used methods used to include X-Ray PDF Studies with the use of Synchrotron Radiation, as well as Differential Scanning Calorimetry (DSC), and Thermogravimetric Analysis (TGA).By building a cohesive model one step at a time we can begin to understand fundamental material characteristics of this fascinating building block of life.Item Open Access Conical shell X-ray beam tomosynthesis and micro-computed tomography for microarchitectural characterisation(Springer Nature, 2023-12-06) Arnold, Emily; Elarnaut, Farid; Downes, David; Evans, J. Paul O.; Greenwood, Charlene; Rogers, Keith D.Bone quality is commonly used to diagnose bone diseases such as osteoporosis, with many studies focusing on microarchitecture for fracture prediction. In this study a bovine distal femur was imaged using both micro-computed tomography (µCT) and tomosynthesis using focal construct geometry (FCG) for comparison of microarchitectural parameters. Six regions of interest (ROIs) were compared between the two imaging modalities, with both global and adaptive methods used to binarize the images. FCG images were downsampled to the same pixel size as the µCT images. Bone morphometrics were determined using BoneJ, for each imaging modality, binarization technique and ROI. Bone area/total area was found to have few significant differences between FCG and µCT (p < 0.05 for two of six ROIs). Fractal Dimension had only one significant difference (p < 0.05 for one of six ROIs) between µCT and downsampled FCG (where pixel size was equalized). Trabecular thickness and trabecular spacing were observed to follow trends as observed for the corresponding µCT images, although many absolute values were significantly different (p < 0.05 for between one and six ROIs depending on image types used). This study demonstrates the utility of tomosynthesis for measurement of microarchitectural morphometrics.Item Open Access Data for: Anisotropy visualisation from X-ray diffraction of biological apatite in mixed phase samples(Cranfield University, 2024-09-06) Scott, Robert; Rogers, Keith; Gosling, Sarah; Arnold, EmilyItem Open Access Data supporting: 'Thermally Dynamic Examination of Local Order in Nanocrystalline Hydroxyapatite'(Cranfield University, 2022-08-31 16:43) Arnold, Emily"Thermally Dynamic Examination of Local Order in Nanocrystalline Hydroxyapatite" Supporting Data Authors: Emily L Arnold*, Sarah Gosling, Samantha K Davies, Hannah L Cross, Dean S Keeble, Paul Evans, Charlene Greenwood, Keith D Rogers * email: E.L.Arnold@cranfield.ac.uk Created: 2022-05-19 ; Last revision: 2022-05-26 Underlying data is given within this dataset. A readMe is provided explaining all files given within this dataset.Item Open Access Investigating pair distribution function use in analysis of nanocrystalline hydroxyapatite and carbonate-substituted hydroxyapatite(International Union of Crystallography, 2022-04-14) Arnold, Emily; Keeble, Dean S.; Evans, J. Paul O.; Greenwood, Charlene; Rogers, Keith D.Hydroxyapatite (HA) is a complex material, which is often nanocrystalline when found within a biological setting. This work has directly compared the structural characteristics derived from data collected using a conventional laboratory-based X-ray diffractometer with those collected from a dedicated pair distribution function (PDF) beamline at Diamond Light Source. In particular, the application of PDF analysis methods to carbonated HA is evaluated. 20 synthetic samples were measured using both X-ray diffraction (XRD) and PDFs. Both Rietveld refinement (of laboratory XRD data) and real-space refinement (of PDF data) were used to analyse all samples. The results of Rietveld and real-space refinements were compared to evaluate their application to crystalline and nanocrystalline hydroxyapatite. Significant relationships were observed between real-space refinement parameters and increasing carbonate substitution. Understanding the local order of synthetic hydroxyapatite can benefit several fields, including both biomedical and clinical settings.Item Open Access Microcalcification crystallography as a potential marker of DCIS recurrence(Springer Nature, 2023-06-08) Gosling, Sarah B.; Arnold, Emily; Davies, Samantha K.Ductal carcinoma in-situ (DCIS) accounts for 20–25% of all new breast cancer diagnoses. DCIS has an uncertain risk of progression to invasive breast cancer and a lack of predictive biomarkers may result in relatively high levels (~ 75%) of overtreatment. To identify unique prognostic biomarkers of invasive progression, crystallographic and chemical features of DCIS microcalcifications have been explored. Samples from patients with at least 5-years of follow up and no known recurrence (174 calcifications in 67 patients) or ipsilateral invasive breast cancer recurrence (179 microcalcifications in 57 patients) were studied. Significant differences were noted between the two groups including whitlockite relative mass, hydroxyapatite and whitlockite crystal maturity and, elementally, sodium to calcium ion ratio. A preliminary predictive model for DCIS to invasive cancer progression was developed from these parameters with an AUC of 0.797. These results provide insights into the differing DCIS tissue microenvironments, and how these impact microcalcification formation.Item Open Access New insights into the application of pair distribution function studies to biogenic and synthetic hydroxyapatites(Springer, 2020-11-11) Arnold, Emily; Keeble, Dean S.; Greenwood, Charlene; Rogers, Keith D.Biogenic and synthetic hydroxyapatites are confounding materials whose properties remain uncertain, even after years of study. Pair distribution function (PDF) analysis was applied to hydroxyapatites in the 1970’s and 1980’s, but this area of research has not taken full advantage of the relatively recent advances in synchrotron facilities. Here, synchrotron X-ray PDF analysis is compared to techniques commonly used to characterise hydroxyapatite (such as wide angle X-ray scattering, Fourier-transform infrared spectroscopy and thermogravimetric analysis) for a range of biogenic and synthetic hydroxyapatites with a wide range of carbonate substitution. Contributions to the pair distribution function from collagen, carbonate and finite crystallite size were examined through principal component analysis and comparison of PDFs. Noticeable contributions from collagen were observed in biogenic PDFs when compared to synthetic PDFs (namely r < 15 Å), consistent with simulated PDFs of collagen structures. Additionally, changes in local structure were observed for PDFs of synthetic hydroxyapatites with differing carbonate content, notably in features near 4 Å, 8 Å and 19 Å. Regression models were generated to predict carbonate substitution from peak position within the PDFs.Item Open Access Reflections and Their Real Space Significance(Cranfield University, 2020-11-27 10:01) Arnold, EmilyBone is a complex composite material made up of three main components, the most abundant of which is the mineral hydroxyapatite. Within many species, hydroxyapatite naturally occurs as a nanocrystalline material, making accurate analysis difficult. Brilliant X-ray sources are used to allow measurement of a much wider range of angular data (from Q = 0.05 to 60 Å-1) than a traditional laboratory X-ray diffractometer (from Q = 0.1 to 8 Å-1). Shown here is diffraction data collected at Diamond Light Source on the dedicated total scattering beamline I15-1. Debye-Scherrer rings can be seen, allowing measurement of crystallographic parameters within reciprocal space. Shadows are seen from the sample changer and an additional detector. This beamline allows for the observation of local coordination of atoms from 0.1nm to 5 nm (through pair distribution function analysis) while simultaneously measuring average crystallite structure.Item Open Access Sparse interleaved sampling for high resolution focal construct geometry X-ray tomography(Optical Society of America, 2023-04-24) Evans, J. Paul O.; Elarnaut, F.; Downes, D.; Lee, W. K.; Arnold, Emily; Rogers, KeithWe demonstrate interleaved sampling by multiplexing conical subshells within the tomosynthesis and raster scanning a phantom through a 150 kV shell X-ray beam. Each view comprises pixels sampled on a regular 1 mm grid, which is then upscaled by padding with null pixels before tomosynthesis. We show that upscaled views comprising 1% sample pixels and 99% null pixels increase the contrast transfer function (CTF) computed from constructed optical sections from approximately 0.6 line pairs/mm to 3 line pairs/mm. The driver of our method is to complement work concerning the application of conical shell beams to the measurement of diffracted photons for materials identification. Our approach is relevant to time-critical, and dose-sensitive analytical scanning applications in security screening, process control and medical imaging.Item Open Access Spinal Motion Segments — I: Concept for a Subject-specific Analogue Model(Springer, 2020-06-24) Franceskides, Constantinos; Arnold, Emily; Horsfall, Ian; Tozzi, Gianluca; Gibson, Michael C.; Zioupos, PeterMost commercial spine analogues are not intended for biomechanical testing, and those developed for this purpose are expensive and yet still fail to replicate the mechanical performance of biological specimens. Patient-specific analogues that address these limitations and avoid the ethical restrictions surrounding the use of human cadavers are therefore required. We present a method for the production and characterisation of biofidelic, patient-specific, Spine Motion Segment (SMS = 2 vertebrae and the disk in between) analogues that allow for the biological variability encountered when dealing with real patients. Porcine spine segments (L1–L4) were scanned by computed tomography, and 3D models were printed in acrylonitrile butadiene styrene (ABS). Four biological specimens and four ABS motion segments were tested, three of which were further segmented into two Vertebral Bodies (VBs) with their intervertebral disc (IVD). All segments were loaded axially at 0.6 mm·min−1 (strain-rate range 6×10−4 s−1–10×10−4 s−1). The artificial VBs behaved like biological segments within the elastic region, but the best two-part artificial IVD were ∼15% less stiff than the biological IVDs. High-speed images recorded during compressive loading allowed full-field strains to be produced. During compression of the spine motion segments, IVDs experienced higher strains than VBs as expected. Our method allows the rapid, inexpensive and reliable production of patient-specific 3D-printed analogues, which morphologically resemble the real ones, and whose mechanical behaviour is comparable to real biological spine motion segments and this is their biggest asset.Item Open Access Spinal Motion Segments — II: Tuning and Optimisation for Biofidelic Performance(Springer, 2020-06-24) Franceskides, Constantinos; Arnold, Emily; Horsfall, Ian; Tozzi, Gianluca; Gibson, Michael C.; Zioupos, PeterMost commercially available spine analogues are not intended for biomechanical testing, and the few that are suitable for using in conjunction with implants and devices to allow a hands-on practice on operative procedures are very expensive and still none of these offers patient-specific analogues that can be accessed within reasonable time and price range. Man-made spine analogues would also avoid the ethical restrictions surrounding the use of biological specimens and complications arising from their inherent biological variability. Here we sought to improve the biofidelity and accuracy of a patient-specific motion segment analogue that we presented recently. These models were made by acrylonitrile butadiene styrene (ABS) in 3D printing of porcine spine segments (T12–L5) from microCT scan data, and were tested in axial loading at 0.6 mm·min−1 (strain rate range 6×10−4 s −1 – 10×10−4 s−1 ). In this paper we have sought to improve the biofidelity of these analogue models by concentrating in improving the two most critical aspects of the mechanical behaviour: the material used for the intervertebral disc and the influence of the facet joints. The deformations were followed by use of Digital Image Correlation (DIC) and consequently different scanning resolutions and data acquisition techniques were also explored and compared to determine their effect. We found that the selection of an appropriate intervertebral disc simulant (PT Flex 85) achieved a realistic force/displacement response and also that the facet joints play a key role in achieving a biofidelic behaviour for the entire motion segment. We have therefore overall confirmed the feasibility of producing, by rapid and inexpensive 3D-printing methods, high-quality patient-specific spine analogue models suitable for biomechanical testing and practiceItem Open Access A subject-specific analogue model for spinal motion segments(European Society of Biomechanics, 2017-07-05) Franceskides, Constantinos; Arnold, Emily; Horsfall, Ian; Tozzi, Gianluca; Zioupos, PeterHuman cadaveric tissues are incredibly variable and difficult to preserve [1], thus making frequent biomechanical testing with these materials challenging. Available funds and ethical procedures will also limit their availability [2]. Due to these restrictions, animal bone models are often used. However, as all biological tissues, those models present variable mechanical properties depending on a number of factors [3]. For the above reasons subject-specific analogues are very attractive, particularly in the field of forensic and injury biomechanics. The analogue proposed in this study was 3D-printed from micro-CT (Computed Tomography) dataset of real bone, through generation of a 3D model. Both cadaveric and analogue segments were mechanically tested in axial compression. And surface displacement was computed via digital image correlation (DIC). The proposed protocol has the potential to be applied in the prediction and modelling of bone behaviour.Item Open Access Supporting data: 'Age Related Changes of Rib Cortical Bone Matrix: Application for Age-at-Death Estimation'(Cranfield University, 2021-01-04 12:17) Bonicelli, Andrea; Zioupos, Peter; Arnold, Emily; Rogers, Keith; Xhemali, Bledar; F. Kranioti, ElenaThis study used autopsy material from 113 rib specimens. A set of 33 parameters were measured by standard bio-mechanical (nanoindentation and microindentation), physical (TGA/DSC, XRD and FTIR) and histomorphometry (porosity-ImageJ) methods. Stepwise regressions were used to create 35 equations that would produce the best ‘estimates of age at death’ vs real age of the cadavers. Five equations were produced; in the best of cases an equation counting 7 parameters had an R2 = 0.863 and mean absolute error of 4.64 years.Item Open Access Thermally dynamic examination of local order in nanocrystalline hydroxyapatite(Elsevier, 2022-08-13) Arnold, Emily; Gosling, Sarah; Davies, Samantha K.; Cross, Hannah L.; Evans, Paul; Keeble, Dean S.; Greenwood, Charlene; Rogers, Keith D.The main mineral component of bone is hydroxyapatite, a commonly nanocrystalline material which presents many challenges for those trying to characterize it. Here, local structure is analyzed using X-ray total scattering for synthetic samples, to enable a better understanding of the nanocrystalline nature of hydroxyapatite. Two samples were measured dynamically during heat treatment from 25°C to 800°C, and were analyzed using small box modelling. Analysis of sequential measurements when dwelling at key temperatures showed a significant relationship between time and temperature, indicating a process occurring more slowly than thermal expansion. This indicates a decrease in B-type CO32- substitution between 550°C and 575°C and an increase in A-type CO32- substitution above 750°C. A greater understanding of local, intermediate, and long-range order of this complex biomineral during heat treatment can be of interest in several sectors, such as in forensic, biomedical and clinical settings for the study of implant coatings and bone diseases including osteoporosis and osteoarthritis.Item Open Access The use of μCT and fractal dimension for fracture prediction in osteoporotic individuals(Elsevier, 2019-12-11) Arnold, Emily; Clement, John; Rogers, Keith D.; Garcia-Castro, Fabio; Greenwood, CharleneOsteoporosis (OP) is a widespread condition with commonly associated fracture sites at the hip, vertebra and wrist. This study examines the effects of age and osteoporosis on bone quality by comparing the efficacy of using parameters which indicate bone quality (both traditional clinical parameters such as bone mineral density (BMD), as well as apparent Young's modulus determined by finite element analysis, among others) to predict fracture. Non-fracture samples were collected from the femoral heads of 83 donors (44 males, 39 females), and fracture samples were obtained from the femoral heads of 17 donors (female). Microarchitectural parameters (Bone Volume/Total Volume [BV/TV], Bone Surface/Bone Volume [BS/BV], Tissue Mineral Density [TMD, etc.]) were measured from μCT of each sample as well as 2D and 3D fractal dimension (D2D and D3D respectively). A cube was cropped from μCT images and an isotropic hexahedral element was assigned to each voxel. Finite element analysis was used to calculate the Young's modulus for each sample. Overall, values for microarchitectural characteristics, fractal dimension measurements and Young's Modulus were consistent with values within literature. Significant correlations are observed between age and BV/TV for non-fracture males and females, as well as between age and volumetric BMD (vBMD) for the same groups. Significant differences are present between age-matched non-fracture and fracture females for BV/TV, BS/BV, vBMD, TMD, D2D, D3D, (p < 0.01 for all). Properties which are not age dependent are significantly different between age-matched non-fracture and fracture specimens, indicating OP is a disease, and not just an accelerated aging process.Item Open Access Wet bone characteristics persist in buried bone after 10 weeks: implications for forensic anthropology(MDPI, 2023-08-26) Maier, Anna Katharina; Manzella, Alessia; Bonicelli, Andrea; Arnold, Emily; Marquez-Grant, Nicholas; Zioupos, PeterAssessing the timing of skeletal trauma significantly impacts the reconstruction of events surrounding death and deposition in forensic cases. However, there are no absolute time frames in which the characteristics of wet bone (peri-mortem) fractures transition to dry (post-mortem) fractures. The aim of this study was to attempt to identify a point within the post-mortem interval in which the characteristics of bone change from wet to dry bone properties. A total of 32 deer ribs were placed in a laboratory burial environment and a set of three were fractured with blunt force trauma every week during a ten-week period. All samples and the inflicted trauma effects were documented and analysed by macroscopic observation, scanning electron microscope (SEM) analysis, thermal analysis, biomechanical analysis, and attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR). No significant difference was found in the macroscopic, microscopic, thermal, and biomechanical analyses of the trauma inflicted over the 10-week period. A significant difference was only found in the carbonate-to-phosphate ratio in analytical chemistry. The results suggest that interpreting wet bone characteristics in forensic anthropology as having been inflicted during the peri-mortem period (around the time of death) should also consider that these, in fact, could be inflicted well after death (post-mortem) as wet bone properties as this study has shown persist at least 10 weeks after death in a burial environment.