We describe analytical procedures for trace element determinations developed at the CNRS Service d'Analyse des Roches et des Minéraux (SARM) and report results obtained for five geochemical reference materials: basalt BR, diorite DR‐N, serpentinite UB‐N, anorthosite AN‐G and granite GH. Results for rare earth elements, U and Th are also reported for other reference materials including dunite DTS‐1, peridotite PCC‐1 and basalt BIR‐1. All rocks were decomposed using alkali fusion. Analyses were done by flow injection ICP‐MS and by on‐line low pressure liquid chromatography (LC)‐ICP‐MS for samples containing very low REE, U and Th concentrations. This latter method yielded limits of determination much lower than data by direct introduction and eliminated possible isobaric interference on these elements. Although results agree with most of the working values, when available, results for some elements differed slightly from the recommended concentrations. In these cases, we propose new values for Co, Y and Zn in basalt BR, Zr in diorite DR‐N, Sr and U in granite GH, and Ga and Y in anorthosite AN‐G. Furthermore, although the Sb concentration measured in AN‐G was very close to our limit of determination, our value (0.3 ± 0.1 μg g−1) is much lower than the reported working value of 1.4 ± 0.2 μg g−1. These new values would need to be confirmed by a new inter‐laboratory programme to further characterise these reference materials.
Results obtained for REE, Th and U concentrations using the on‐line low pressure LC‐ICP‐MS yielded good limits of determination (ng g−1to sub‐ng g−1for rocks and ng l−1to sub‐ng l−1for natural waters) and accurate results. The efficiency of the matrix separation allowed accurate measurements of Eu without the need to correct the BaO isobaric interference for samples having Ba/Eu ratios as high as 27700. For REE concentrations in PCC‐1 and DTS‐1, differences with values reported in the literature are interpreted as resulting from possible heterogeneity of the reference materials. Thorium and U values are proposed for these two samples, as well as for AN‐G and UB‐N.
Objective. To analyse how the main components of the disease phenotype (sicca symptoms, diagnostic tests, immunological markers and systemic disease) can be driven by the age at diagnosis of primary Sjögren's syndrome (pSS). Methods. By January 2021, the participant centres had included 12,753 patients from 25 countries that fulfilled the 2002/2016 classification criteria for pSS. The age at diagnosis was defined as the time when the attending physician confirmed fulfilment of the criteria. Patients were clustered according to age at diagnosis. 50 clusters with more than 100 observations (from 27 to 76 years) were used to study the influence of the age at diagnosis in the disease expression. Results. There was a consistent increase in the frequency of oral dryness according to the age at diagnosis, with a frequency of <90% in patients diagnosed at the youngest ages and >95% in those diagnosed at the oldest ages. The smooth curves that best fitted a linear model were the frequency of dry mouth (adjusted R 2 0.87) and the frequency of abnormal oral tests (adjusted R 2 0.72). Therefore, for each 1-year increase in the age at diagnosis, the frequency of dry mouth increased by 0.13%, and the frequency of abnormal oral diagnostic tests by 0.11%.
Abstract. The influence of gradients in bulk elastic strain energy on the dissolution and growth behaviour of minerals in rocks is commonly considered negligible. We experimentally observed, however, that regular arrays of macroscopically visible etch grooves may develop on the originally smooth free surfaces of soluble crystals held in an undersaturated aqueous solution if the crystals are only elastically stressed. These grooves are oriented perpendicular to the compressive stress. They disappear soon after the stress is taken off. The formation of the grooves is well explained by recent theories on the instability of the surface of stressed solids. Development of such instabilities could significantly affect the grain boundary structure in rocks, and have a major effect on dissolution and growth processes.
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