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Pre-Romanesque murals at Kostoľany pod Tríbečom, Slovakia, have been investigated by portable X-ray fluorescence and by microanalytical methods to identify painting materials (pigments and binders), and to explain the degradation of colours. Today, missing green and blue shades have been reconstructed according to residual concentrations of Cu, which correspond to copper chlorides-products of salt corrosion of the copper carbonates azurite and/or malachite, accelerated by micro-organisms. As confirmed by powder X-ray microdiffraction, original minium (Pb3O4) has been transformed to brown-black plattnerite (PbO2). In increased humidity, even insoluble pigments are washing down from the walls and the intensity of colours further diminishes. [ABSTRACT FROM AUTHOR]

While the most famous historical green earth deposits in Italy and Cyprus were exceptionally rich in celadonite, the deposits near Kadaň, Czech Republic, consisted of thin Fe-rich celadonite impregnations accompanied by interstratified celadonite/smectite. In superimposed tuffs, smectites become prevalent and their colour changes from forest to olive green. Powder X-ray microdiffraction and infrared microspectroscopy permit us to distinguish between green earth minerals in microsamples taken from works of art. The Ti contents and the Fe/Mg ratios help to indicate the presence of Bohemian green earth from Kadaň. We found this material in local 18th-century works of art and also in paintings by Anton Kern (1709-47). [ABSTRACT FROM AUTHOR]

Abstract: The adsorption of cesium on various smectite-rich clays was studied as a function of the initial concentration of cesium and in the presence of competitive ions (Na+, K+ and Ca2+) using the radiotracer method, examining the effects of the clay structure and comparing the behaviour of bentonites with that of sedimentary clays. The experiments were performed under laboratory conditions, at 22–25 °C, in ambient atmosphere and using synthetic average granite groundwater as the liquid phase. Reference smectites (STx−1, SAz−1), illite (IMt−1) and kaolinite (KGa−2), three Czech smectite-rich clays (bentonite from Rokle, sedimentary clays from Skalná and Maršov) and three Spanish bentonites from Cabo de Gata were used as the natural sorbents. The adsorption data were fitted by the Freundlich isotherm. Smectites exhibited the highest values of the adsorption capacity and the highest affinity for cesium within the studied concentration range, 10−6 to 10−1 M. The K d values disclosed two different trends—a relatively constant adsorption rate at Cs concentrations below 10−2 M (typical for smectites–bentonites from Spain), or a continuous decrease in the adsorption rate over the whole concentration range (“non-smectites”, such as illite and kaolinite-sedimentary clays (Skalná, Maršov). Therefore, the higher contents of illite and kaolinite (48 wt.% in Skalná and 25 wt.% in Maršov) significantly influence the cesium adsorption trend and the cation exchange capacities of the bulk material. Surprisingly, the Rokle bentonite, containing more than 60 wt.% of expandable clay structures, shows the “non-smectite” trend. This can be explained by the possible presence of expandable vermiculite in addition to smectite. The cesium adsorption behaviour of vermiculite is considered similar to that of illite. For trace cesium concentrations (10−6 M), the major competitive ion is K+, followed by Ca2+ and finally by Na+. Bentonites are more affected than sedimentary clays containing illite—this is due to the ion exchange mechanism predominating in the adsorption on smectites, compared to specific selective adsorption on illite and mica-type clay minerals. [Copyright &y& Elsevier]

The following case report describes a 66-year-old woman who presented with abdominal pain and renal pelvis dilatation. Based on imaging methods, a primary urinary system tumor was suspected. However, targeted biopsy surprisingly revealed the presence of extramedullary multiple myeloma. The patient was then found to harbor a rare chromosomal aberration t (6; 22). [ABSTRACT FROM AUTHOR]

Paintings represent composed materials arranged in successive layers. Development of a suitable method for a depth-profiling analysis is essential for acquiring the information on the stratigraphy as well as on the chemical composition of individual layers, revealing the pigments which had been used. In this study, a depth-resolved analysis of multi-layered model samples of historical easel paintings was performed by means of laser-induced breakdown spectroscopy (LIBS) in combination with non-invasive X-ray fluorescence (XRF). The LIBS analysis was carried out using modified laser ablation system, UP-266 MACRO, equipped with a Czerny-Turner spectrometer. The XRF analysis was performed by handheld spectrometer, Delta Premium. In LIBS experiments, a set of six spots was examined with 5, 10, 15, 20, 25 and 30 pulses respectively, for each of the studied paint samples. Digital and 3D optical microscopy was employed to measure individual layer thickness and to obtain the information on average ablation rates of each sample. The chemical composition of the model samples with each layer partly uncovered was known, and this enabled to directly compare the results obtained by LIBS depth profiling with a fast analysis carried out with the handheld XRF spectrometer. The LIBS depth profiling proved to be a suitable method to distinguish layers of a different material composition and estimate their thickness. The combined use of LIBS and XRF analyses offered essential complementary information on the elemental composition of analysed multi-layered samples. [ABSTRACT FROM AUTHOR]

Vivianite (Fe3(PO4)2·8H2O) is a rare blue historical pigment, which can be profitably used in authorship ascription or copy identification. However, its tendency to degrade complicates its proper identification in paint layers. Reference vivianite mineralogical samples were analysed in order to compare and to test the limits of structural analyses on possibly degraded vivianite samples (X‐ray diffraction and vibrational spectroscopies). The same methods, in their μ‐configuration, were tested on micro‐samples of the paintings and their limits evaluated. A sedimentary origin of the pigment has been suggested. Vivianite was detected in various works by Jean George de Hamilton (1672–1737) and in a Late Gothic Transylvanian altarpiece. [ABSTRACT FROM AUTHOR]

Single-crystals of the layered copper hydroxide acetate Cu2(OH)3(CH3COO)·H2O were synthesized by heating copper acetate solution at 60 °C. The standard synthesis of the title compound based on slow titration of copper acetate solution with NaOH yielded materials with worse morphology and an additional phase present. The obtained products were characterized with powder X-ray diffraction, high temperature powder X-ray diffraction, scanning electron microscopy and infrared spectroscopy. The crystal structure was determined from single-crystal X-ray diffraction data, collected both at 120 K and at 293 K. The title compound crystallizes in the monoclinic botallackite-type layered structure, space group P 21, with the lattice parameters a = 5.5776(3) Å, b = 6.0733(2) Å, c = 18.5134(8) Å, β = 91.802(4)° and a = 5.5875(4)Å, b = 6.0987(4) Å, c = 18.6801(10)Å, β = 91.934(5)° for 120 K and for 293 K, respectively. Acetate groups and water molecules are interlayered between corrugated sheets of edge-sharing CuO6 octahedra exhibiting strong distortion resulted from the Jahn-Teller effect. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Abstract: Measurement of magnetic susceptibility (MS) and diffuse reflectance spectra (DRS) were used to construct environmental proxies in a 6.5 m section of the sediment core VER98-1-13 from the Academician Ridge, Lake Baikal. The interpretation of MS and DRS was supported by X-ray diffraction and microparticle voltammetry to identify the main Fe-bearing minerals. The record of the relative paleointensity of the Earth''s magnetic field was used to construct an age model showing the core interval covers the last 160 ky. The time resolution of the record was ∼1 ky. The main environmental changes were recognized by a combination of DRS and MS records and compared to marine isotopic stages in addition to the diatom record from 120 to 60 ky BP so as to demonstrate the importance of these inorganic proxies as paleoenvironmental records. A dramatic climatic deterioration between 66 and 60 ky BP was probably preceded by a dry intermediate stage between 77 and 66 ky BP. The DRS-based proxies of Fe(II)/Fe(III) ratios in the mineral assemblage, MS and/or diatom records clearly reveal 1–2 ky long environmental extremes at 110, 103, 90, 85, 77, 61, 54, 36, 27, 23, and 19 ky BP. The majority of these extremes were contemporaneous with discharges of North Atlantic and Arctic Ocean icebergs (Heinrich events) documenting a teleconnection between the North Atlantic Ocean and East Central Siberia. These sharp changes coincided with a major transition to the colder climatic stages of the last 100 ky. [Copyright &y& Elsevier]

Sorption is an important process for the transport of radionuclides through backfill materials in a radioactive waste underground repository. Within this study, sorption of Cs on selected Czech clay materials and their mixtures with sand was investigated by batch tests. The experiments were performed under oxic conditions at 25°C. Synthetic groundwater as a liquid phase and unconditioned clays (as they were provided by their producer) were used to reach the natural conditions as close as possible. Distribution ratios (Rds) of Cs for all selected clays rise with increase of the clay fraction in clay/sand mixtures in agreement with previous works studying sorption behaviour of such mixtures. The rise of Rds is from 102 cm3 g-1 for mixtures with 80% of sand to 103 cm3 g-1 for pure clays. There are significant differences between natural and technologically modified clays. [Copyright &y& Elsevier]

Quartz sand containing mineral impurities was subjected to bioleaching with Bacillus spp. strains and subsequent elutriation. Bioleaching of the sample removed visible Fe-bearing minerals that coated quartz grains. During the bioleaching, elements were dissolved from silicate minerals. Poorly crystalline Fe-oxides that sealed siderite nodules were released from intergranular spaces and formed a fine-grained (<0.1 mm) fraction. Voltammetry of the fine-grained fraction indicated reductive dissolution of Fe3+. However, chemical analysis showed a slight increase in Fe2O3 content and a decrease in the FeO content following three months bioleaching in the Bacillus culture. X-ray diffraction analyses showed the loss of Fe-bearing minerals and mica following the bioleaching and the elutriation of the fine-grained fraction. Transmission electron microscopy and energy-dispersive analysis of X-rays showed nucleation of fine-grained Fe,Al-silicates on bacterial surface after three months of bioleaching. [Copyright &y& Elsevier]