CERES :: Browsing by Author "Rogers, Keith"

Browsing by Author "Rogers, Keith"

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Open Access
Age-related changes in femoral head trabecular microarchitecture
(Buck Institute for Age Research, 2017-10-11) Greenwood, Charlene; Clement, John; Dicken, Anthony; Evans, Paul; Lyburn, Iain Douglas; Martin, Richard M.; Stone, Nick; Zioupos, Peter; Rogers, Keith
Osteoporosis is a prevalent bone condition, characterised by low bone mineral density and increased fracture risk. Currently, the gold standard for identifying osteoporosis and increased fracture risk is through quantification of bone mineral density using dual energy X-ray absorption. However, many studies have shown that bone strength, and consequently the probability of fracture, is a combination of both bone mass and bone ‘quality’ (architecture and material chemistry). Although the microarchitecture of both non-fracture and osteoporotic bone has been previously investigated, many of the osteoporotic studies are constrained by factors such as limited sample number, use of ovariectomised animal models, and lack of male and female discrimination. This study reports significant differences in bone quality with respect to the microarchitecture between fractured and non-fractured human femur specimens. Micro-computed tomography was utilised to investigate the microarchitecture of femoral head trabecular bone from a relatively large cohort of non-fracture and fracture human donors. Various microarchitectural parameters have been determined for both groups, providing an understanding of the differences between fracture and non -fracture material. The microarchitecture of non-fracture and fracture bone tissue is shown to be significantly different for many parameters. Differences between sexes also exist, suggesting differences in remodelling between males and females in the fracture group. The results from this study will, in the future, be applied to develop a fracture model which encompasses bone density, architecture and material chemical properties for both female and male tissues.
Open Access
An approach to high-throughput X-ray diffraction analysis of combinatorial polycrystalline thin film libraries
(Blackwell Publishing Ltd, 2009-04-30T00:00:00Z) Roncallo, S.; Karimi, O.; Rogers, Keith; Lane, David W.; Ansari, S. A.
With the demand for higher rates of discovery in the materials field, characterization techniques that are capable of rapidly and reliably surveying the characteristics of large numbers of samples are essential. A chemical combinatorial approach using thin films can provide detailed phase diagrams without the need to produce multiple, individual samples. This is achieved with compositional gradients forming high-density libraries. Conventional raster scanning of chemical or structural probes is subsequently used to interrogate the libraries. A new, alternative approach to raster scanning is introduced to provide a method of high-throughput data collection and analysis using an X-ray diffraction probe. Libraries are interrogated with an extended X-ray source and the scattering data collected using an area detector. A simple technique of 'partitioning' this scattering distribution enables determination of information comparable to conventional raster scanned results but in a dramatically reduced collection time. The technique has been tested using synthetic X-ray scattering distributions and those obtained from contrived samples. In all cases, the partitioning algorithm is shown to be robust and to provide reliable data; discrimination along the library principal axis is shown to be similar to 500 mm and the lattice parameter resolution to be similar to 10(-3) A angstrom mm(-1). The limitations of the technique are discussed and future potential applications described.
Open Access
Breast calcification micromorphology classification
(British Institute of Radiology, 2022-07-25) Robert Scott, Robert Scott; Iain Lyburn, Iain Lyburn; Cornford, Eleanor; Bouzy, Pascaline; Stone, Nicholas; Greenwood, Charlene; Bouybayoune, Ihsanne; Pinder, Sarah; Rogers, Keith
Objectives: The importance of consistent terminology in describing the appearance of breast calcifications in mammography is well recognised. Imaging of calcifications using electron microscopy is a globally growing field of research. We therefore suggest that the time is ripe to develop a lexicon of terms for classifying the micromorphology of breast calcifications. Methods: Calcifications within a wide range of histological sections of breast tissue, both benign and malignant, were imaged by Scanning Electron Microscopy (SEM). These images were examined, and the micromorphology of calcifications present was grouped to create a classification system. Results: Based on the appearance of the calcifications observed, we propose five main categories for classification of the micromorphology of breast calcifications, namely Dense Homogenous, Punctulate, Banded, Spongy, and Aggregate. Conclusions: Use of the descriptive categories outlined here will help to ensure consistency and comparability of published observations on the micromorphology of breast calcifications. Advances in knowledge: This is the first time a lexicon and classification system has been proposed for the micromorphology of breast calcifications, as observed by scanning electron microscopy of histological sections. This will facilitate comparability of observed relationships between micromorphology, mammographic appearance, chemistry, and pathology.
Open Access
Calcification microstructure reflects breast tissue microenvironment
(Springer, 2019-12-05) Gosling, Sarah; Scott, Robert; Greenwood, Charlene; Bouzy, Pascaline; Nallala, Jayakrupakar; Lyburn, Iain Douglas; Stone, Nicholas; Rogers, Keith
Microcalcifications are important diagnostic indicators of disease in breast tissue. Tissue microenvironments differ in many aspects between normal and cancerous cells, notably extracellular pH and glycolytic respiration. Hydroxyapatite microcalcification microstructure is also found to differ between tissue pathologies, including differential ion substitutions and the presence of additional crystallographic phases. Distinguishing between tissue pathologies at an early stage is essential to improve patient experience and diagnostic accuracy, leading to better disease outcome. This study explores the hypothesis that microenvironment features may become immortalised within calcification crystallite characteristics thus becoming indicators of tissue pathology. In total, 55 breast calcifications incorporating 3 tissue pathologies (benign – B2, ductal carcinoma in-situ - B5a and invasive malignancy - B5b) from archive formalin-fixed paraffin-embedded core needle breast biopsies were analysed using X-ray diffraction. Crystallite size and strain were determined from 548 diffractograms using Williamson-Hall analysis. There was an increased crystallinity of hydroxyapatite with tissue malignancy compared to benign tissue. Coherence length was significantly correlated with pathology grade in all basis crystallographic directions (P < 0.01), with a greater difference between benign and in situ disease compared to in-situ disease and invasive malignancy. Crystallite size and non-uniform strain contributed to peak broadening in all three pathologies. Furthermore, crystallite size and non-uniform strain normal to the basal planes increased significantly with malignancy (P < 0.05). Our findings support the view that tissue microenvironments can influence differing formation mechanisms of hydroxyapatite through acidic precursors, leading to differential substitution of carbonate into the hydroxide and phosphate sites, causing significant changes in crystallite size and non-uniform strain.
Open Access
Chapter 6: X-Ray diffraction and focal construct technology
(CRC Press, 2018-11-02) Rogers, Keith; Evans, Paul
This chapter examines the background and practice of X-ray diffraction (XRD) and considers this phenomenon principally in the context of X-ray-based security screening. The focus will be upon the practical aspects of XRD as many texts already provide comprehensive descriptions of the relevant theoretical background and that of the closely associated area of crystallography. X-ray diffraction and its development from simple materials identification to dynamic imaging will be considered, followed by a similar view of aviation screening. Subsequently, a new approach to the harvesting of diffraction signatures (Focal Construct Technology) will be introduced and consequent potential applications summarised.
Open Access
The characterisation and provenancing of ancient ochres
(Cranfield University, 2010-04) Attard Montalto, Nicola; Rogers, Keith; Shortland, Andrew J.
Open Access
Classification of fracture and non-fracture groups by analysis of coherent X-ray scatter
(Nature Publishing Group, 2016-07-01) Dicken, A. J.; Evans, J. Paul O.; Rogers, Keith; Stone, N.; Greenwood, Charlene; Godber, S. X.; Clement, J. G.; Lyburn, Iain Douglas; Martin, R. M.; Zioupos, Peter
Osteoporotic fractures present a significant social and economic burden, which is set to rise commensurately with the aging population. Greater understanding of the physicochemical differences between osteoporotic and normal conditions will facilitate the development of diagnostic technologies with increased performance and treatments with increased efficacy. Using coherent X-ray scattering we have evaluated a population of 108 ex vivo human bone samples comprised of non-fracture and fracture groups. Principal component fed linear discriminant analysis was used to develop a classification model to discern each condition resulting in a sensitivity and specificity of 93% and 91%, respectively. Evaluating the coherent X-ray scatter differences from each condition supports the hypothesis that a causal physicochemical change has occurred in the fracture group. This work is a critical step along the path towards developing an in vivo diagnostic tool for fracture risk prediction.
Open Access
Confocal energy-dispersive X-ray diffraction tomography employing a conical shell beam
(Optical Society of America, 2019-07-01) Dicken, Anthony; Evans, J. Paul O.; Rogers, Keith; Prokopiou, Danae; Godber, Simon; Elarnaut, F.; Shevchuk, Alex; Downes, D.; Wilson, M.
We introduce a new high-energy X-ray diffraction tomography technique for volumetric materials characterization. In this method, a conical shell beam is raster scanned through the samples. A central aperture optically couples the diffracted flux from the samples onto a pixelated energy-resolving detector. Snapshot measurements taken during the scan enable the construction of depth-resolved dark-field section images. The calculation of dspacing values enables the mapping of material phase in a volumetric image. We demonstrate our technique using five ~15 mm thick, axially separated samples placed within a polymer tray of the type used routinely in airport security stations. Our method has broad analytical utility due to scalability in both scan size and X-ray energy. Additional application areas include medical diagnostics, materials science, and process control
Open Access
Conical shell illumination incorporating a moving aperture for depth-resolved high-energy X-ray diffraction
(Royal Society of Chemistry, 2023-01-16) Spence, Daniel; Dicken, Anthony; Downes, David; Rogers, Keith; Evans, Paul
In many applications, the main limitation of X-ray absorption methods is that the signals measured are a function of the attenuation coefficient, which tells us almost nothing about the chemical or crystallographic nature of objects under inspection. To calculate fundamental crystallographic parameters requires the measurement of diffracted photons from a sample. Standard laboratory diffraction methods have been refined for well over a century and provide ‘gold standard’ structural models for well-prepared samples and single crystals but have little applicability for thick heterogeneous samples as demanded by many screening applications. We present a new high-energy X-ray diffraction probe, which in comparison with previous depth-resolving hollow beam techniques, requires a single beam, point detector and a simple swept aperture to resolve sample signatures at unknown locations within an inspection space. We perform Monte Carlo simulations to support experiments on both single- and multiple-material localisation and identification. The new probe is configured and tested using low-cost commercial components to provide a rapid and cost-effective solution for applications including explosives detection, process control and diagnostics.
Open Access
Contrasting the crystallinity indicators of heated and diagenetically altered bone mineral
(Elsevier, 2010-10-01) Rogers, Keith; Beckett, Sophie; Kuhn, Samira; Chamberlain, Andrew; Clement, John
Modifications to bone mineral as a result of diagenesis or heating include a marked increase in crystallinity. Although these processes are not completely understood a number of simple, pragmatic approaches are in general use to quantify crystallinity and thus provide a relative metric for features such as preservation state. A preliminary investigation into the interpretation of crystallinity as measured by X-ray diffraction has been undertaken. The microstructural changes associated with diagenetically altered (archaeological) and heated contemporary bone have been examined. A common analysis approach was adopted and thus direct comparison between the physical features of these material systems has been possible. The data clearly demonstrate the pronounced anisotropic nature of the crystallite microstructure for both diagenetically altered and contemporary bone. The limitations of adopting simple crystallinity indices for characterising such materials are explored. Crystallite size and strain were shown to be dependent upon crystallographic direction. Overall, the diagenetically altered bone mineral possessed greater long range lattice order than that of contemporary heated bone. Further, significant differences between the directional nature of the microstructure of diagenetically altered and modern heated bone were observed. This study has enabled a direct comparison of the effects of heating and diagenesis upon bone mineral. It has demonstrated the need to consider bone microstructure anisotropically.
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, Emily
Open Access
Data supporting "A new parafocusing paradigm for X-ray diffraction"
(Cranfield University, 2020-12-09 10:07) Prokopiou, Danae; McGovern, James; Davies, Gareth; Godber, Simon; Rogers, Keith; Evans, Paul; Dicken, Anthony
A new approach to parafocusing X-ray diffraction implemented with an annular incident beam is demonstrated for the first time. The method exploits an elliptical specimen path on a flat sample to produce relatively high intensity maxima that can be measured with a point detector. It is shown that the flat-specimen approximation tolerated by conventional Bragg–Brentano geometries is not required. A theoretical framework, simulations and experimental results for both angular- and energy-dispersive measurement modes are presented and the scattering signatures compared with data obtained with a conventional pencil-beam arrangement.
Open Access
Depth resolved snapshot energy-dispersive X-ray diffraction using a conical shell beam
(Optical Society of America, 2017-08-23) Dicken, A. J.; Evans, J. Paul O.; Rogers, Keith; Prokopiou, Danae; Godber, S. X.; Wilson, M.
We demonstrate a novel imaging architecture to collect range encoded diffraction patterns from overlapping samples in a single conical shell projection. The patterns were measured in the dark area encompassed by the beam via a centrally positioned aperture optically coupled to a pixelated energy-resolving detector. We show that a single exposure measurement of 0.3 mAs enables d-spacing values to be calculated. The axial positions of the samples were not required and the resultant measurements were robust in the presence of crystallographic textures. Our results demonstrate rapid volumetric materials characterization and the potential for a direct imaging method, which is of great relevance to applications in medicine, non-destructive testing and security screening.
Open Access
Design optimisation of the feeding system of a novel counter-gravity casting process
(MDPI, 2018-10-11) Papanikolaou, Michail; Pagone, Emanuele; Georgarakis, Konstantinos; Rogers, Keith; Jolly, Mark R.; Salonitis, Konstantinos
The appropriate design of feeders in a rigging system is critical for ensuring efficient compensation for solidification shrinkage, thus eliminating (shrinkage-related) porosity and contributing to the production of superior quality castings. In this study, a multi-objective optimisation framework combined with Computational Fluid Dynamics (CFD) simulations has been introduced to investigate the effect of the feeders’ geometry on shrinkage porosity aiming to optimise casting quality and yield for a novel counter-gravity casting process (CRIMSON). The weighted sum technique was employed to convert this multi-objective optimisation problem to a single objective one. Moreover, an evolutionary multi-objective optimisation algorithm (NSGA-II) has been applied to estimate the trade-off between the objective functions and support decision makers on selecting the optimum solution based on the desired properties of the final casting product and the process characteristics. This study is one of the first attempts to combine CFD simulations with multi-objective optimisation techniques in counter-gravity casting. The obtained results indicate the benefits of applying multi-objective optimisation techniques to casting processes
Open Access
Developing focal construct technology for in vivo diagnosis of osteoporosis
(IOP, 2019-03-18) Greenwood, Charlene; Rogers, Keith; Wilson, M.; Lyburn, Iain Douglas; Evans, P.; Prokopiou, Danae
Osteoporosis is a prevalent bone disease around the world, characterised by low bone mineral density and increased fracture risk. Currently, the gold standard for identifying osteoporosis and increased fracture risk is through quantification of bone mineral density (BMD), using dual energy X-ray absorption (DEXA). However, the use of BMD to diagnose osteoporosis is not without limitation and arguably the risk of osteoporotic fracture should be determined collectively by bone mass, architecture and physicochemistry of the mineral composite building blocks. Rather than depending exclusively on the 'mass' of bone, our previous research investigated predicting the risk of fracture using 'bone quality'. The work highlighted that the material properties of OP tissue differ significantly to that of 'normal' bone and for the first time reported the clinical value of new biomarkers (obtained from X-ray scatter signatures) for fracture risk prediction. Thus, in order to improve fracture prediction models, diagnostic tools need to be developed which not only measure bone mineral density, but also bone quality. This pilot study builds on our previous work and aims to develop a new technology, Focal Construct Technology (FCT), which is hoped can measure XRD signatures in vivo. Our previous work was performed entirely with interrogating probes applied in transmission mode. This has some disadvantages that would be overcome were reflection mode employed. This study involves the creation of unique, high impact data with the potential to form the basis of a new generation of medical diagnostic instrumentation. A systematic series of conventional reflection mode ex vivo experiments were performed in which bone specimens were examined through increasing thicknesses of overlaying muscle/fat/skin. Further, we applied FCT to these geometries. This had not previously been attempted and required some initial modelling to ensure correct topologies of the hollow beams. The results from this study suggest it may be possible to obtain the parameters in vivo with the same precision as those obtained within the laboratory when using FCT.
Open Access
Diffraction enhanced kinetic depth X-ray imaging
(2013-12-04) Dicken, Anthony; Rogers, Keith; Evans, P.
An increasing number of fields would benefit from a single analytical probe that can characterise bulk objects that vary in morphology and/or material composition. These fields include security screening, medicine and material science. In this study the X-ray region is shown to be an effective probe for the characterisation of materials. The most prominent analytical techniques that utilise X-radiation are reviewed. The study then focuses on methods of amalgamating the three dimensional power of kinetic depth X-ray (KDFX) imaging with the materials discrimination of angular dispersive X-ray diffraction (ADXRD), thus providing KDEX with a much needed material specific counterpart. A knowledge of the sample position is essential for the correct interpretation of diffraction signatures. Two different sensor geometries (i.e. circumferential and linear) that are able to collect end interpret multiple unknown material diffraction patterns and attribute them to their respective loci within an inspection volume are investigated. The circumferential and linear detector geometries are hypothesised, simulated and then tested in an experimental setting with the later demonstrating a greater ability at discerning between mixed diffraction patterns produced by differing materials. Factors known to confound the linear diffraction method such as sample thickness and radiation energy have been explored and quantified with a possible means of mitigation being identified (i.e. via increasing the sample to detector distance). A series of diffraction patterns (following the linear diffraction appoach) were obtained from a single phantom object that was simultaneously interrogated via KDEX imaging. Areas containing diffraction signatures matched from a threat library have been highlighted in the KDEX imagery via colour encoding and match index is inferred by intensity. This union is the first example of its kind and is called diffraction enhanced KDEX imagery. Finally an additional source of information obtained from object disparity is explored as an alternative means of calculating sample loci. This offers a greater level of integration between these two complimentary techniques as object disparity could be used to reinforce the results produced by the linear diffraction geometry.
Open Access
Dual conical shell illumination for volumetric high-energy x-ray diffraction imaging
(Royal Society of Chemistry, 2018-09-13) Dicken, Anthony; Spence, Daniel; Rogers, Keith; Prokopiou, Danae; Evans, Paul
To retrieve crystallographic information from extended sample volumes requires a high-energy probe. The use of X-rays to combine imaging with materials characterisation is well-established. However, if fundamental crystallographic parameters are required, then the collection and analysis of X-rays diffracted by the inspected samples are prerequisites. We present a new X-ray diffraction imaging architecture, which in comparison with previous depth-resolving hollow beam techniques requires significantly less X-ray power or alternatively supports significantly increased scanning speeds. Our conceptual configuration employs a pair of conical shell X-ray beams derived from a single point source to illuminate extended samples. Diffracted flux measurements would then be obtained using a pair of energy resolving point detectors. This dual beam configuration is tested using a single X-ray beam set-up employing a dual scan. The use of commercial off-the-shelf low-cost components has the potential to provide rapid and cost-effective performance in areas including industrial process control, medical imaging and explosives detection.
Open Access
The effect of moderate temperatures on latent fingerprint chemistry
(Sage, 2017-03-14) Johnston, Andrew; Rogers, Keith
The effect of moderate temperatures (25–75 ℃) on latent fingerprints over a five-hour period was examined using Fourier transform infrared (FT-IR) microspectroscopy. The aim of the study was to detect changes in IR spectra due to any changes in fingerprint chemistry; these results were then compared to pure compounds found in sebum that was subjected to 75 ℃ for 5 h. Latent fingerprints deposited on CaF2 microscope slides and placed on a Peltier pump heating stage showed that higher temperatures significantly reduced the quantity of sebaceous compounds after 5 h, whereas temperatures below 45 ℃ had little effect on the quantity of these compounds over the same time period. Fourier transform infrared microspectroscopy allowed for the real-time detection of changes to the IR spectra and demonstrated an increase in the OH stretch band (3250 cm–1) over 5 h at all temperatures investigated, suggesting various oxidation processes were taking place. Pure samples analyzed included squalene, fatty acids, wax esters, and mixed triglycerides. Unsaturated lipids showed a similar increase in the OH stretch band to the latent fingerprints whereas saturated compounds showed no change over time. This information is required to better understand the effect of moderate temperatures on latent fingerprints and how these temperatures could affect aged print composition.
Open Access
Elemental and phase composition of breast calcifications
(2017-06-14) Scott, Robert; Rogers, Keith; Kendall, Catherine; Stone, Nicholas
Despite the importance of calcifications in early detection of breast cancer, and their proposed association with tumour growth, remarkably little detail is known about their chemical composition, or how this relates to pathology. One reason for this gap is the difficulty of systematically and precisely locating calcifications for analysis, particularly in sections taken from diagnostic archives. Two simple methods were developed which can achieve this in sections cut from wax embedded breast tissue. These are based on micro-CT and x-ray fluoroscopy mapping, and were used to locate calcifications for further study. The elemental composition of calcifications in histological sections was measured using energy-dispersive x-ray spectroscopy in an environmental scanning electron microscope. Variations in Ca:P ratio could in principle be detected non-invasively by dual energy absorptiometry, as demonstrated in a proof of principle experiment. However, the Ca:P ratio was found to lie in a narrow range similar to bone, with no significant difference between benign and malignant. In contrast, a substantial and significant difference in Na:Ca ratio was found between benign and malignant specimens. This has potential for revealing malignant changes in the vicinity of a core needle biopsy. The phase composition and crystallographic parameters within calcifications was measured using synchrotron x-ray diffraction. This is the first time crystallite size and lattice parameters have been measured in breast calcifications, and it was found that these both parallel closely the changes in these parameters with age observed in foetal bone. It was also discovered that these calcifications contain a small proportion of magnesium whitlockite, and that this proportion increases from benign, to carcinoma in-situ, to invasive cancer. When combined with other recent evidence on the effect of magnesium on hydroxyapatite precipitation, this suggests a mechanism explaining observations that carbonate levels within breast calcifications are lower in malignant specimens.
Open Access
Elemental vs. phase composition of breast calcifications
(Nature Publications, 2017-03-09) Scott, Robert; Kendall, Catherine; Stone, Nicholas; Rogers, Keith
Despite the importance of calcifications in early detection of breast cancer, and their suggested role in modulating breast cancer cell behaviour, very little detail is known about their chemical composition or how this relates to pathology. We measured the elemental composition of calcifications contained within histological sections of breast tissue biopsies, and related this to both crystallographic parameters measured previously in the same specimens, and to the histopathology report. The Ca:P ratio is of particular interest since this theoretically has potential as a non-invasive aid to diagnosis; this was found to lie in a narrow range similar to bone, with no significant difference between benign and malignant. The Mg:Ca ratio is also of interest due to the observed association of magnesium whitlockite with malignancy. The initially surprising inverse correlation found between whitlockite fraction and magnesium concentration can be explained by the location of the magnesium in calcified tissue. Sodium was also measured, and we discovered a substantial and significant difference in Na:Ca ratio in the apatite phase between benign and malignant specimens. This has potential for revealing malignant changes in the vicinity of a core needle biopsy.

Browsing by Author "Rogers, Keith"

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