A multi-analytical approach to gold in Ancient Egypt: studies on provenance and corrosion

Recent results from a three-year multi-disciplinary project on Ancient Egyptian gold jewellery revealed that items of jewellery from the Middle Kingdom to the New Kingdom were manufactured using a variety of alluvial gold alloys. These alloys cover a wide range of colours and the majority contain Platinum Group Elements inclusions. However, in all the gold foils analysed, these inclusions were found to be absent. In this work a selection of gilded wood and leather items and gold foil fragments, all from the excavations by John Garstang at Abydos (primarily from Middle Kingdom graves), were examined using Scanning Electron Microscopy-Energy Disperse Spectroscopy (SEM-EDS), X-Ray Fluorescence (µXRF), Particle Induced X-Ray Emission (µPIXE) and Double Dispersive X-Ray Fluorescence (D2XRF). The work allowed us to characterise the composition of the base-alloys and also to reveal the presence of Pt at trace levels, confirming the use of alluvial gold deposits. Corrosion products were also investigated in the foils where surface tarnish was visually observed. Results showed that the differences in the colour of corrosion observed for the foils are related not only to the thickness of the corrosion layer but also to a multi-layer structure containing the various corrosion products

PET C-11 acetate is also a perfusion tracer for kidney evaluation purposes

International audienceRationale: Renal positron emission tomography (PET) functional imaging allows non-invasive and dynamic measurements of functional and metabolic parameters. [O-15]H2O is used as a perfusion tracer, and [C-11]acetate as an oxidative metabolism in this purpose, requiring two injections to assess those fundamental parameters. Yet, in cardiac physiology study, the high first-pass myocardial extraction fraction of [C-11]acetate allowed to use its influx rate as a blood flow marker too. Since [C-11]acetate has been characterized by a 20-25% single pass renal extraction in dogs, it could be used as a potential tracer for renal perfusion. The aim of this study was to determine whether [C-11]acetate influx rate can be used as quantitative in vivo marker of kidney perfusion in human. Methods: In 10 healthy subjects, dynamic PET acquisitions were performed after [O-15]H2O and [C-11]acetate injections spaced by a 15-minute interval. As previously validated, with compartmental modeling of kinetics, renal perfusion and oxidative metabolism were estimated respectively with influx rate of [O-15]H2O and efflux rate of [C-11]acetate. Additionally, influx rate of [C-11]acetate was regressed to influx rate of [O-15]H2O. Results: Renal time activity curves of [C-11]-acetate was best fitted with a mono compartmental model compared to a bi-compartmental model (p \textless 0.0001). [C-11]acetate influx rate was significantly correlated with perfusion quantified with [O-15]H2O (r(2) = 0.37, p \textless 0.001) at baseline. This regression allowed the computation of a renal [C-11]acetate extraction fraction (EF), and further the computation of renal blood flow from its influx rate. Conclusion: In healthy subjects, over a wide range of renal perfusion, direct estimates of renal oxygen consumption as well as tissue perfusion can be obtained by PET with a single tracer [C-11]acetate. This approach needs to be validated in CKD patients, and would be of great interest to design clinical protocol aiming at evaluating ischemic nephropathies candidate to revascularization. (C) 2019 Elsevier Inc. All rights reserved

'To acquire a good name': Specimens of nineteenth century Persian tile making from the Tehran workshop of the master potter Ali Muhammad Isfahani

This paper presents the analytical results obtained on the study of a green pigment, part of 23 samples of raw materials from the late 19th century Persian workshop of the master potter Ali Muhammad Isfahani, today in the collection of the Victoria and Albert Museum, London. In collaboration with institutions in the United Kingdom and France the samples were investigated using non-invasive and non-destructive analytical techniques to characterise their quantitative elementary composition and the structure of crystalline and amorphous phases present. The composition of the green sample was compared with a treatise by the master potter, which illustrates his description of the working process and with results obtained from one of his finished tiles, now in the collection of the National Museums Scotland. It is hoped that the analytical investigation of the raw material together with the finished object will help our art historical understanding of the workshop