European cobalt sources identified in the production of Chinese Famille Rose porcelain

The blue pigments on 112 fragments or small objects of Qing Dynasty Chinese, 95 of underglaze blue and white and 17 overglaze enamelled porcelains were analysed by LA-ICPMS. The underglaze blues on both blue and white and polychrome objects were created with a cobalt pigment that was rich in manganese with lesser nickel and zinc. This suite of accessory elements is generally considered to be characteristic of local, Chinese, sources of pigments. However, the blue enamels were very different. The cobalt pigment here has low levels of manganese and instead is rich in nickel, zinc, arsenic and bismuth. No Chinese source of cobalt with these characteristics is known, but they closely match the elements found in the contemporary cobalt source at Erzgebirge in Germany. Textual evidence has been interpreted to suggest that some enamel pigment technologies were transferred from Europe to China, but this is the first analytical evidence to be found that an enamel pigment itself was imported. It is possible that this pigment was imported in the form of cobalt coloured glass, or smalt, which might account for its use in enamels, but not in an underglaze, where the colour might be susceptible to running. Furthermore, the European cobalt would have given a purer shade of blue than the manganese-rich Chinese cobalt

Perfusion assessment in rat spinal cord tissue using photoplethysmography and laser Doppler flux measurements

Animal models are widely used to investigate the pathological mechanisms of spinal cord injury (SCI), most commonly in rats. It is well known that compromised blood flow caused by mechanical disruption of the vasculature can produce irreversible damage and cell death in hypoperfused tissue regions and spinal cord tissue is particularly susceptible to such damage. A fiberoptic photoplethysmography (PPG) probe and instrumentation system were used to investigate the practical considerations of making measurements from rat spinal cord and to assess its suitability for use in SCI models. Experiments to assess the regional perfusion of exposed spinal cord in anesthetized adult rats using both PPG and laser Doppler flowmetry (LDF) were performed. It was found that signals could be obtained reliably from all subjects, although considerable intersite and intersubject variability was seen in the PPG signal amplitude compared to LDF. We present results from 30 measurements in five subjects, the two methods are compared, and practical application to SCI animal models is discussed

The investigation and characterisation of colourless glass from forensic and archaeological contexts using multiple interdisiplinary analytical techniques

The techniques used to analyse glass in forensics and archaeology differ: forensic analysis relies almost completely on Refractive Index, whereas archaeology uses compositional analyses. This thesis focuses on examining, explaining and challenging those differences through the analysis of colourless glass from forensic and archaeological contexts. Two major studies are undertaken, one focussing on stained and painted glass from Christ Church Cathedral, Oxford, and one based on modern automotive glass. The analytical techniques common to each discipline are applied to the samples of glass used in the research. The studies each focus on individual research questions; the Christ Church study investigates the 17th century Van Linge window scheme, the compositions of fragments of glass from throughout the cathedral’s history are investigated, and shown to separate into distinct compositional groups. The study also successfully recreates the Van Linge window scheme; and the historical and compositional analyses allowed the study of one of the in-situ painted windows in the cathedral. The automotive glass study investigates the complex relationship between glass manufacturers and vehicle manufacturers. The research revealed that certain makes of vehicle were beginning to group and glass from specific areas of the world was also grouping together. This study highlights the potential use for glass as a tool for intelligence gathering rather than just as evidence. The application of the different analytical techniques to each study is discussed along with the merits of using each of the techniques. The potential of using forensic techniques in archaeology and archaeological techniques in forensics is evaluated. Specifically, LA-ICP-MS, which is rarely used in forensics, could be an innovative and potentially important tool for the forensic evaluation of cars and other glass evidence. A discussion of the research and databases needed to make the most of the techniques is assessed.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

The investigation and characterisation of colourless glass from forensic and archaeological contexts using multiple interdisiplinary analytical techniques

The techniques used to analyse glass in forensics and archaeology differ: forensic analysis relies almost completely on Refractive Index, whereas archaeology uses compositional analyses. This thesis focuses on examining, explaining and challenging those differences through the analysis of colourless glass from forensic and archaeological contexts. Two major studies are undertaken, one focussing on stained and painted glass from Christ Church Cathedral, Oxford, and one based on modern automotive glass. The analytical techniques common to each discipline are applied to the samples of glass used in the research. The studies each focus on individual research questions; the Christ Church study investigates the 17th century Van Linge window scheme, the compositions of fragments of glass from throughout the cathedral’s history are investigated, and shown to separate into distinct compositional groups. The study also successfully recreates the Van Linge window scheme; and the historical and compositional analyses allowed the study of one of the in-situ painted windows in the cathedral. The automotive glass study investigates the complex relationship between glass manufacturers and vehicle manufacturers. The research revealed that certain makes of vehicle were beginning to group and glass from specific areas of the world was also grouping together. This study highlights the potential use for glass as a tool for intelligence gathering rather than just as evidence. The application of the different analytical techniques to each study is discussed along with the merits of using each of the techniques. The potential of using forensic techniques in archaeology and archaeological techniques in forensics is evaluated. Specifically, LA-ICP-MS, which is rarely used in forensics, could be an innovative and potentially important tool for the forensic evaluation of cars and other glass evidence. A discussion of the research and databases needed to make the most of the techniques is assessed.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

High-resolution X-ray diffraction with no sample preparation

It is shown that energy-dispersive X-ray diffraction (EDXRD) implemented in a back-reflection geometry is extremely insensitive to sample morphology and positioning even in a high-resolution configuration. This technique allows high quality X-ray diffraction analysis of samples that have not been prepared and is therefore completely non-destructive. The experimental technique was implemented on beamline B18 at the Diamond Light Source synchrotron in Oxfordshire, UK. The majority of the experiments in this study were performed with pre-characterized geological materials in order to elucidate the characteristics of this novel technique and to develop the analysis methods. Results are presented that demonstrate phase identification, the derivation of precise unit-cell parameters and extraction of microstructural information on unprepared rock samples and other sample types. A particular highlight was the identification of a specific polytype of a muscovite in an unprepared mica schist sample, avoiding the time-consuming and difficult preparation steps normally required to make this type of identification. The technique was also demonstrated in application to a small number of fossil and archaeological samples. Back-reflection EDXRD implemented in a high-resolution configuration shows great potential in the crystallographic analysis of cultural heritage artefacts for the purposes of scientific research such as provenancing, as well as contributing to the formulation of conservation strategies. Possibilities for moving the technique from the synchrotron into museums are discussed. The avoidance of the need to extract samples from high-value and rare objects is a highly significant advantage, applicable also in other potential research areas such as palaeontology, and the study of meteorites and planetary materials brought to Earth by sample-return missions

The ‘expat factor’: the influence of working time on women's decisions to undertake international assignments in the oil and gas industry

This article examines the effect of working time on women’s willingness to go on expatriate assignments in the oil and gas exploration and production sector. The research draws upon an analysis of two case study firms’ international assignment and working time policies, semi-structured interviews with 14 Human Resource staff responsible for policy design and implementation, and a survey of the views of 71 women expatriates, supported by in-depth interviews with 26 of the survey respondents. The research identifies an ‘expat factor’: assignees state that long hours are inherent in expatriation and necessary to further their careers. However in practice, working time is not excessive and flexible working practices are utilised. Hours of work have little effect on women’s decisions to undertake long-term assignments but alternatives such as short-term and commuter assignments are unpopular as their working patterns are disruptive to family life. This article contributes to theory development by linking two discrete frameworks that explain women’s career choices when they strive to balance their career goals with their families and by identifying a career compromise threshold when expatriation is rejected in favour of family considerations. A model is proposed to link working time/patterns to women’s international assignment participation

Proteomics of Multiple Sclerosis : inherent issues in defining the pathoetiology and identifying (early) biomarkers

Multiple Sclerosis (MS) is a demyelinating disease of the human central nervous system having an unconfirmed pathoetiology. Although animal models are used to mimic the pathology and clinical symptoms, no single model successfully replicates the full complexity of MS from its initial clinical identification through disease progression. Most importantly, a lack of preclinical biomarkers is hampering the earliest possible diagnosis and treatment. Notably, the development of rationally targeted therapeutics enabling pre‐emptive treatment to halt the disease is also delayed without such biomarkers. Using literature mining and bioinformatic analyses, this review assessed the available proteomic studies of MS patients and animal models to discern (1) whether the models effectively mimic MS; and (2) whether reasonable biomarker candidates have been identified. The implication and necessity of assessing proteoforms and the critical importance of this to identifying rational biomarkers are discussed. Moreover, the challenges of using different proteomic analytical approaches and biological samples are also addressed

CD8 T-cell recruitment into the central nervous system of cuprizone-fed mice : relevance to modelling the etiology of Multiple Sclerosis

Cuprizone (CPZ)-feeding in mice induces atrophy of peripheral immune organs (thymus and spleen) and suppresses T-cell levels, thereby limiting its use as a model for studying the effects of the immune system in demyelinating diseases such as Multiple Sclerosis (MS). To investigate whether castration (Cx) can protect the peripheral immune organs from CPZ-induced atrophy and enable T-cell recruitment into the central nervous system (CNS) following a breach of the blood-brain barrier (BBB), three related studies were carried out. In Study 1, Cx prevented the dose-dependent reductions (0.1% < 0.2% CPZ) in thymic and splenic weight, size of the thymic medulla and splenic white pulp, and CD4 and CD8 (CD4/8) levels remained comparable to gonadally intact (Gi) control males. Importantly, 0.1% and 0.2% CPZ were equipotent at inducing central demyelination and glial activation. In Study 2, combining Cx with 0.1% CPZ-feeding and BBB disruption with pertussis toxin (PT) enhanced CD8+ T-cell recruitment into the CNS. The increased CD8+ T-cell level observed in the parenchyma of the cerebrum, cerebellum, brainstem and spinal cord were confirmed by flow cytometry and western blot analyses of CNS tissue. In Study 3, PT+0.1% CPZ-feeding to Gi female mice resulted in similar effects on the peripheral immune organs, CNS demyelination, and gliosis comparable to Gi males, indicating that testosterone levels alone were not responsible for the immune response seen in Study 2. The combination of Cx+0.1% CPZ-feeding+PT indicates that CPZ-induced demyelination can trigger an “inside-out” immune response when the peripheral immune system is spared and may provide a better model to study the initiating events in demyelinating conditions such as MS

Suppression of the peripheral immune system limits the central immune response following cuprizone-feeding : relevance to modelling Multiple Sclerosis

Cuprizone (CPZ) preferentially affects oligodendrocytes (OLG), resulting in demyelination. To investigate whether central oligodendrocytosis and gliosis triggered an adaptive immune response, the impact of combining a standard (0.2%) or low (0.1%) dose of ingested CPZ with disruption of the blood brain barrier (BBB), using pertussis toxin (PT), was assessed in mice. 0.2% CPZ(±PT) for 5 weeks produced oligodendrocytosis, demyelination and gliosis plus marked splenic atrophy (37%) and reduced levels of CD4 (44%) and CD8 (61%). Conversely, 0.1% CPZ(±PT) produced a similar oligodendrocytosis, demyelination and gliosis but a smaller reduction in splenic CD4 (11%) and CD8 (14%) levels and no splenic atrophy. Long-term feeding of 0.1% CPZ(±PT) for 12 weeks produced similar reductions in CD4 (27%) and CD8 (43%), as well as splenic atrophy (33%), as seen with 0.2% CPZ(±PT) for 5 weeks. Collectively, these results suggest that 0.1% CPZ for 5 weeks may be a more promising model to study the ‘insideout’ theory of Multiple Sclerosis (MS). However, neither CD4 nor CD8 were detected in the brain in CPZ±PT groups, indicating that CPZ-mediated suppression of peripheral immune organs is a major impediment to studying the ‘inside-out’ role of the adaptive immune system in this model over long time periods. Notably, CPZ(±PT)-feeding induced changes in the brain proteome related to the suppression of immune function, cellular metabolism, synaptic function and cellular structure/organization, indicating that demyelinating conditions, such as MS, can be initiated in the absence of adaptive immune system involvement