Publications by authors named "R D Speller"

The evaluation of 3D printed osteological materials has highlighted the difficulties associated with accurately representing fine surface details on printed bones. Moreover, there is an increasing need for reconstructions to be demonstrably accurate and reliable for use in the criminal justice system. The aim of this study was to assess the surface quality of 3D prints (n = 9) that presented with micromorphological alterations from trauma, taphonomy and pathology processes.

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Drug crystallisation in the skin is recognised as a significant problem in topical and transdermal drug delivery. Our recent investigations provided new evidence of drug crystallisation in the skin, however, confirming the precise location of crystals remains challenging. Of note, most approaches used have required disruption of the membrane by tape stripping, with crystal detection limited to the superficial skin layers.

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The Antikythera Mechanism is an extraordinarily complex ancient Greek astronomical calculating device whose mode of operation is now relatively well understood particularly since imaging studies in 2005 revealed gears and inscriptions which were previously illegible. Unfortunately, the highest resolution X-ray computed tomography image of the largest fragment had some errors which meant that the reconstructed images were not as clear as had been expected. Here, the original X-ray data have been reanalysed and reconstructed.

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The first step that is required to extract the correct information from a two-dimensional (2D) diffraction signature is to remove the background accurately. However, direct background subtraction inevitably overcorrects the signal as it does not take into account the attenuation by the sample. Other traditional background removal methods, such as the rolling ball technique, can separate sharp diffraction peaks of crystalline materials from their background.

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A system using energy-dispersive X-ray diffraction (EDXRD) has been developed and tested using multivariate calibration for the quantitative analysis of tablet-form mixtures of common pharmaceutical ingredients. A principal advantage of EDXRD over the more traditional and common angular dispersive X-ray diffraction technique (ADXRD) is the potential of EDXRD to analyse tablets within their packaging, due to the higher energy X-rays used. In the experiment, a series of caffeine, paracetamol and microcrystalline cellulose mixtures were prepared and pressed into tablets.

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