361 research outputs found

    Non-ferrous metalworking in England: Late Iron Age to Early Medieval

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    Evidence for non-ferrous metalworking in the late Iron Age to early medieval periods comes mainly from archaeological finds, though Roman and medieval writings supply some supporting information. A gazetteer of sites which have produced evidence for metalworking is provided and these finds are categorised and described together with details of the processes in which they were used or produced. The spatial and temporal distributions of finds of all types are also discussed and reasons suggested for some of the patterns that emerge. The processes for which evidence is presented include refining, alloying, melting, casting, smithing and decorating. The majority of the data derives from the working of copper and its alloys though gold, silver, lead, tin and their alloys are also covered. The uses made of different alloys throughout the period of the study is also discussed. A more detailed survey of Roman copper alloy usage is based on analyses of over 3,000 late Iron Age and Roman brooches and nearly 900 other objects. Nearly 1,000 of the brooch analyses were quantitative ones carried out by atomic absorption spectrometry while the remainder were qualitative X-ray fluorescence analyses. Many of the metalworking finds were also analysed qualitatively by X-ray fluorescence. These two strands of evidence are complementary and together provide a mass of evidence for how metals and alloys were worked and the uses that were made of them

    Recent advances in the genetics of SDH-related paraganglioma and pheochromocytoma

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    The last 10 years have seen enormous progress in the field of paraganglioma and pheochromocytoma genetics. The identification of the first gene related to paraganglioma, SDHD, encoding a subunit of mitochondrial succinate dehydrogenase (SDH), was quickly followed by the identification of mutations in SDHC and SDHB. Very recently several new SDH-related genes have been discovered. The SDHAF2 gene encodes an SDH co-factor related to the function of the SDHA subunit, and is currently exclusively associated with head and neck paragangliomas. SDHA itself has now also been identified as a paraganglioma gene, with the recent identification of the first mutation in a patient with extra-adrenal paraganglioma. Another SDH-related co-factor, SDHAF1, is not currently known to be a tumor suppressor, but may shed some light on the mechanisms of tumorigenesis. An entirely novel gene associated with adrenal pheochromocytoma, TMEM127, suggests that other new paraganglioma susceptibility genes may await discovery. In addition to these recent discoveries, new techniques related to mutation analysis, including genetic analysis algorithms, SDHB immunohistochemistry, and deletion analysis by MLPA have improved the efficiency and accuracy of genetic analysis. However, many intriguing questions remain, such as the striking differences in the clinical phenotype of genes that encode proteins with an apparently very close functional relationship, and the lack of expression of SDHD and SDHAF2 mutations when inherited via the maternal line. Little is still known of the origins and causes of truly sporadic tumors, and the role of oxygen in the relationships between high-altitude, familial and truly sporadic paragangliomas remains to be elucidated
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