Genetic effects of static magnetic fields. Body size increase and lethal mutations induced in populations of Drosophila melanogaster after chronic exposure

International audienc

Cathodoluminescence, Raman and scanning electron microscopy with energy dispersion system mapping to unravel the mineralogy and texture of an altered Ca-Al-rich inclusion in Renazzo CR2 carbonaceous chondrite

An altered fluffy type A Ca-Al-rich inclusion in the CR2 Renazzo carbonaceous chondrite was examined by combined Raman, scanning electron microscopy with energy dispersion system (SEM-EDS) and cathodoluminescence (CL) mapping. Blue CL at 450 nm and orange emission at 600 nm were related to anorthite and calcite, respectively. Raman spectra were highly fluorescent, and only the stronger peaks of anorthite, clinopyroxene and calcite were observed. Raman-induced fluorescence emission was measured using the 632-nm Raman laser source, up to 850 nm, and used to chart the mineral phases. A fluorescence structured peak at 690 nm, split in three subpeaks at 678, 689 and 693 nm, was found; it is likely related to the fluorescence emission of Cr3+ from a fassaitic pyroxene in anorthite. Secondary pyroxene in the Wark–Lovering rim does not show the peak at 690 nm; the different fluorescence emission from the secondary rim and the pyroxene patches within anorthite could be a marker to spot the primary pyroxene. From combined imaging, the events in the altered chondrite could be sequenced. Starting from a pristine assemblage of spinel and melilite, with little fassaite, several alteration episodes occurred. Alteration in secondary anorthite, which could be mapped by the blue CL emission at 450 nm, was followed by alkalization, with rims of sodalite and nepheline, and subsequent formation of secondary clinopyroxene, encircling the inclusion. Widespread calcite alteration, present also in the matrix between chondrules, was the last recorded event

A multi-methodological study of the (K,Ca)-variety of the zeolite merlinoite

A multi-methodological study of the (K,Ca)-variety of the zeolite merlinoite from Fosso Attici, Sacrofano, Italy was carried out on the basis of electron microprobe analysis in wavelength dispersive mode, singlecrystal X-ray diffraction (at 100 K), Raman and infrared spectroscopy. The chemical formula of the merlinoite from Fosso Attici is (Na0.37K5.69)\u3a3=6.06(Mg0.01Ca1.93Ba0.40)\u3a3=2.34(Fe3+0.02Al10.55Si21.38)\u3a3=31.9O64\u38719.6H2O, compatible with the ideal chemical formula K6Ca2[Al10Si22O64]\u38720H2O. Anisotropic structure refinements confirmed the symmetry and the framework model previously reported (space group Immm, a = 14.066(5),b = 14.111(5), c = 9.943(3) \uc5 at 100 K). Refinement converged with four cationic sites and sixH2Osites; refined bond distances of the framework tetrahedra suggest a highly disordered Si/ Al-distribution. The Raman spectrum of merlinoite (collected between 100 and 4000 cm 121) is dominated by a doublet of bands between 496\u2013422 cm 121, assigned to tetrahedral T\u2013O\u2013T symmetric bending modes. T\u2013O\u2013T antisymmetric stretching is also observed; stretching and bending modes of the H2O molecules are only clearly visiblewhen using a blue laser. The single-crystal near-infrared spectrum shows a very weak band at 6823 cm 121, assigned to the first overtone of the O\u2013H stretching mode, and a band at 5209 cm 121, due to the combination of H2O stretching and bendingmodes.Avery broad and convoluted absorption, extending from 3700 to 3000 cm 121 occurs in the H2O stretching region, while the \u3bd2 bending mode of H2O is found at 1649 cm 121. The powder midinfrared spectrum of merlinoite between 400\u20131300 cm 121 is dominated by tetrahedral T\u2013O\u2013T symmetric and antisymmetric stretches. Raman and Fourier-transform infrared spectroscopy spectra of merlinoite and phillipsite provide a quick identification tool for these zeolites, which are often confused due to their close similarity

Multi-technique characterization of glass mosaic tesserae from Villa di Teodorico in Galeata (Italy)

Several glass mosaic tesserae were found during the archeological excavations at the Villa di Teodorico in Galeata (Forl\uec-Cesena, Emilia Romagna, Italy), dated to early sixth century AD. This work reports the results of an archeometrical investigation realized through a multi-technique approach on 16 tesserae. The aims of the study were the determination of the glass composition, the characterization of coloring and opacifying agents, and the definition of the technological processes involved. The glass matrix and the dispersed crystallites were characterized in detail through micro-Raman spectroscopy, field emission scanning electron microscopy with energy-dispersive X-ray spectroscopy, and X-ray powder diffraction analyses. Micro-Raman spectroscopy was proven to be very effective in the analysis of complex objects, providing information on the structure and composition of the glass and on the nature of the opacifying agents and the crystalline colorants. UV\u2013visible\u2013NIR diffuse reflectance spectrophotometry with optic fibers was helpful to identify the metal ions used as chromophores. The different hues were obtained by means of dispersed ions as well as crystalline compounds and metal nanoparticles. A large variety of opacifying agents was detected. Results were compared with data of contemporary mosaics within the same geographical area

An in-and-out-the-lab Raman spectroscopy study on street art murals from Reggio Emilia in Italy

The street art murals ‘The Big Mother’ by Gola Hundun, the ‘Big Sacral Bird’ by Kenor, the ‘Oriental Carpet” by H101 and “The Economy Subdues You” by Zosen, belonging to the Cooperative Popular Houses of Mancasale and Coviolo in Reggio Emilia (Italy), were investigated by the use of various mobile Raman spectrometers coupled to different lasers and by micro-Raman spectroscopy on selected samples. The study was made necessary by the evident fading of many colours, despite the young age of the paintings, realized in 2010. The first step of the investigation, realized by the on-site campaign, was the identification of the materials, and in particular of the dyes. The main chromophores were identified as polycyclic, monoazo- and disazo- organic pigments, with inorganic compounds as bismuth vanadate (BiVO4) together with the extensive presence of rutile (TiO2). The second step was devoted to the study of the degradation mechanism affecting the colourful layers of the murals. It required the use of laboratory micro-spectrometers and was carried out on a reduced set of samples, selected during the in-situ campaign. This combination of on-site and laboratory Raman spectroscopy allowed the obtaining of the complete identification of the palette used by the different artists in a single day of measurements, in a complete non-destructive day. In addition, it was possible to minimize the number of samples required for the study of the degradation process. Graphical abstract: [Figure not available: see fulltext.