The degradation of cadmium sulfide (CdS)–based oil paints is a phenomenon potentially threatening the iconic painting The Scream (ca. 1910) by Edvard Munch (Munch Museum, Oslo) that is still poorly understood. Here, we provide evidence for the presence of cadmium sulfate and sulfites as alteration products of the original CdS-based paint and explore the external circumstances and internal factors causing this transformation. Macroscale in situ noninvasive spectroscopy studies of the painting in combination with synchrotron-radiation x-ray microspectroscopy investigations of a microsample and artificially aged mock-ups show that moisture and mobile chlorine compounds are key factors for promoting the oxidation of CdS, while light (photodegradation) plays a less important role. Furthermore, under exposure to humidity, parallel/secondary reactions involving dissolution, migration through the paint, and recrystallization of water-soluble phases of the paint are associated with the formation of cadmium sulfates.
Descending necrotising mediastinitis can complicate oropharyngeal infection and has a high associated mortality. We present three cases treated in our department and propose a treatment algorithm based on our experience and literature review. The primary oropharyngeal infection was peritonsillar abscess in two cases and odontogenic abscess in one. Two patients underwent cervicotomy and later thoracotomy. The third underwent cervicotomy with transcervical mediastinal drainage and later required pericardial drainage via a subxiphoid incision. All recovered fully and were discharged within 6 weeks. To enable successful treatment, diagnosis needs to be prompt and surgical drainage adequate. Thoracic management of the chest is essential.
Three types of alloys were recognized when analyzing pre-Columbian artifacts from the North of Peru: gold, silver, and copper alloys; gilded copper and silver; silvered copper; tumbaga, i.e., copper or silver enriched on gold at the surface by depletion gilding. In this paper, a method is described to differentiate gold alloys from gilded copper and from copper-gold tumbaga, and silver alloys from silvered copper and copper-silver tumbaga. This method is based on the use of energy-dispersive X-ray fluorescence, i.e., on a sophisticated analysis of XRF-spectra carrying out an accurate determination of Cu(K (alpha) /K (beta) ), Ag(K (alpha) /K (beta) ), Au(L (alpha) /L (beta) ), and Au-L (alpha) /Cu-K (alpha) or Ag-K (alpha) /Cu-K (alpha) ratios. That implies a dedicated software for the quantitative determination of the area of X-ray peaks. This method was first checked by a relevant number of standard samples and then it was applied to pre-Columbian alloys from the North of Peru
In this work, 102 fragments of Marajoara ceramics, belonging to the National Museum collection (Rio de Janeiro, Brazil), were analyzed using energy dispersive X-ray fluorescence (EDXRF) and principal component analysis (PCA) in order to identify possible groups of samples that present similar behaviors or different characteristics. This information will give an important aid to a more accurate classification of these artifacts. The EDXRF measurements were carried out with a portable system developed in the Nuclear Instrumentation Laboratory consisting of an Oxford TF3005 X-ray tube, with W anode, and an Si-PIN XR-100CR detector from Amptek, working at 25 kV and 100 µA, acquisition time of 600 s and a beam collimation of 2 mm. PCA applied to the X-ray fluorescence results revealed a clear cluster separation to the samples.
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