Materials analysis in three paintings of Thomas Gainsborough (1727-1788) by portable X-ray fluorescence.

Three paintings of Thomas Gainsborough (1727-1788), one of the most influential English portrait painters of the late 18th century, from the collection of the Museu de Arte de São Paulo (MASP) - "Francis Rawdon" (1783-1784), "Portrait of Mrs. John Bolton" (1770), and "Drinkstone Park" (1747) - were investigated using portable X-ray fluorescence (pXRF), employing a W tube anode and an XR-100CR detector. These artworks represent the only paintings by Thomas Gainsborough located in the southern hemisphere.

A study by portable X-ray fluorescence (pXRF) of the painting "Still Life with Vase, Plate and Flowers" (1886-1888).

Portable energy-dispersive X-ray fluorescence spectroscopy (pXRF) was employed in the characterization of the pigments present in the painting "Still Life with Vase, Plate and Flowers", of unknown authorship, but previously attributed to Vincent van Gogh, belonging to the collection of the São Paulo Museum of Art (MASP). In situ pXRF measurements were carried out by means of a portable system in order to provide the museum with a scientific documentation about the materials in the painting. Spectra were taken at different color regions and different hues in the pictorial layer.

Multi-scale approach to assess total porosity and pore size in four different kinds of carbonate rocks.

Petroleum is, at present, still the main energy source in the world. Most of it is stored in carbonate rock reservoirs with complex inner structures and pores ranging from nanometers to dozens of meters. Knowing the rock's entire pore network is indispensable to perform an effective petroleum extraction.

Total Reflection X-ray Fluorescence spectrometry determination of titanium dioxide released from UV-protective textiles during wash.

The aim of this study is to determine the release of TiO from six sport garments into the wash water after 1, 2 and 10 washes. For such, Total Reflection X-ray Fluorescence (TXRF) spectrometry was employed for the study of the wash water and Scanning Electron Microscopy - Energy Dispersive Spectrometry (SEM-EDS) was used for the analysis of the textiles. Results showed that the six sport garments released between 0.

Non-destructive portable X-ray fluorescence analysis of the Portrait of a Young Man with a Golden Chain (c. 1635) by Rembrandt and/or atelier.

XRF is a suitable tool for studies of cultural heritage, since it provides valuable information about the chemical composition of an artefact by means of a non-invasive, multi-elemental and non-destructive in situ analysis. This work presents and discuss the technical examination of the Portrait of a Young Man with a Golden Chain (c. 1635), a wood panel historically attributed to Rembrandt van Rijn and/or atelier, from the São Paulo Museum of Art (MASP) collection.

Microporosity and polymerization contraction as function of depth in dental resin cements by X-ray computed microtomography.

This research aimed to obtain the depth dependence of polymerization contraction and microporosity from irradiated dental resin cements by X-ray computed microtomography (μCT). Samples (n = 5) of commercial Relyx U200 (RU) and AllCem Core (AC) dual-cure resin cements were injected in a cylindrical Teflon sampler (25 mm ) and separated according to polymerization mechanism: self-cured (not irradiated) and dual-cured (irradiated from the top surface with a LED device). The cement's volume was scanned with the μCT scanning conditions kept constant.

Characterization of Brazilian banknotes using portable X-ray fluorescence and Raman spectroscopy.

As technology advances, counterfeiters improve their techniques reproducing banknotes with more accuracy. Spectroscopic techniques may be applied for characterization of these forgeries. The aim of this study was to develop a methodology for banknotes characterization employing portable X-ray fluorescence (pXRF) and portable Raman spectroscopy (RS) equipment for measurements in genuine and counterfeit Real (Brazilian currency) banknotes.

Reactive oxygen species and other biochemical and morphological biomarkers in the gills and kidneys of the Neotropical freshwater fish, Prochilodus lineatus, exposed to titanium dioxide (TiO) nanoparticles.

This study investigated the action of titanium dioxide nanoparticles (TiO-NPs), on the gills and kidneys of Neotropical freshwater fish, Prochilodus lineatus, with emphasis on reactive oxygen species (ROS) production, antioxidant responses, and morphological changes. Fish were exposed to 1, 5, 10, and 50 mg L nominal TiO-NPs suspended into water for 2 or 14 days. In gills, ROS decreased and glutathione (GSH) increased after 2 days, while ROS and GSH increased and superoxide dismutase activity decreased after 14 days.

Mitochondria-rich cells adjustments and ionic balance in the Neotropical fish Prochilodus lineatus exposed to titanium dioxide nanoparticles.

Manufactured titanium dioxide nanoparticles (TiO-NP) have been intensely applied in numerous industrial products and may be a risk for aquatic systems as they are not completely removed from domestic and industrial wastes after water treatment. This study evaluated the osmo- and ionic balance, Na/K-ATPase, H-ATPase and carbonic anhydrase activities and the mitochondria-rich cells (MRC) in the gills and kidney of the Neotropical fish Prochilodus lineatus after 2 (acute) and 14 (subchronic) days of exposure to nominal 0, 1, 5, 10 and 50 mg L TiO-NP. The nominal concentrations corresponded to 0.

Polymerization shrinkage and porosity profile of dual cure dental resin cements with different adhesion to dentin mechanisms.

This research aims to probe the porosity profile and polymerization shrinkage of two different dual cure resin cements with different dentin bonding systems. The self-adhesive resin cement RelyX U200 (named RU) and the conventional Allcem Core (named AC) were analyzed by x-ray microtomography (μCT) and Scanning Electron Microscopy (SEM). Each cement was divided into two groups (n = 5): dual-cured (RUD and ACD) and self-cured (RUC and ACC).

Pore size distributions convolution for microtomographic images applied to Shark Bay's oolite.

In the study of pore size distributions within microtomographic images, there is no consensus in how to group pore size distributions obtained at different spatial resolutions in a single distribution, which represents the properties of the sample in a better way. This work presents a proposition that allows to group pore size distributions obtained by microtomography images in different spatial resolutions. A Shark's Bay oolite was imaged by X-ray microtomography at 4.

Determining chemical composition of materials through micro-CT images.

X-ray microtomography is a 3D non-destructive method which, through digital images, enables a view of the internal structure of samples. Recently, researchers have been extensively performing various methods in the attempt to determine the chemical composition of materials. This paper brings further insight into this matter and proposes a new experimental method for determining the internal chemical composition of samples.

Accuracy evaluation of an X-ray microtomography system.

Microstructural parameter evaluation of reservoir rocks is of great importance to petroleum production companies. In this connection, X-ray computed microtomography (μ-CT) has proven to be a quite useful method for the assessment of rocks, as it provides important microstructural parameters, such as porosity, permeability, pore size distribution and porous phase of the sample. X-ray computed microtomography is a non-destructive technique that enables the reuse of samples already measured and also yields 2-D cross-sectional images of the sample as well as volume rendering.

Quantification of fluids injection in a glass-bead matrix using X-ray microtomography.

Several daily activities involve the accumulation or percolation of fluids through porous media. X-ray microtomography is a non-invasive technique capable of providing images of the internal microstructure of materials showing the different phases of fluid distribution present in the sample directly or at the pore-scale. This methodology was used to qualitatively and quantitatively assess samples consisting with glass beads of standard size, which contained fluid filling a porous region.

Effective atomic number and density determination of rocks by X-ray microtomography.

Microtomography, as a non-destructive technique, has become an important tool in studies of internal properties of materials. Recently, interest using this methodology in characterizing the samples with respect to their compositions, especially rocks, has grown. Two physical properties, density and effective atomic number, are important in determining the composition of rocks.

Use of portable X-ray fluorescence (PXRF) in vivo as an alternative technique for the assessment of iron levels in patients with thalassemia and hemochromatosis.

This work investigated the viability of the portable x-ray fluorescence (PXRF) technique as a means of measuring iron levels in patients suffering from thalassemia major (beta-thalassemia) and hereditary hemochromatosis (HH or Haemochromatosis) or other iron-overload conditions. Measurements were conducted at the University Hospital Blood Center and in the Laboratory of Applied Nuclear Physics at the State University of Londrina, Brazil. One thalassemia major patient and four healthy people were grouped.

Effects of manual threshold setting on image analysis results of a sandstone sample structural characterization by X-ray microtomography.

Binarization process plays an important role in structural characterization by means of micro-CT images analysis. The choice of the correct threshold to separate porous phase from the material is the procedure for binary images creation. Slight variations of the threshold level led to substantial variations in physical parameters determination.

Trypanosoma cruzi: in vivo evaluation of iron in skin employing X-ray fluorescence (XRF) in mouse strains that differ in their susceptibility to infection.

Trypanosoma cruzi, the causative agent of Chagas' disease (CD), is a substantial public health concern in Latin America. Laboratory mice inoculated with T. cruzi have served as important animal models of acute CD.

Some geological characteristics in a regolith-limey shale rock profile through natural radionuclides distribution.

The objective of this work is to study some geological characteristics in a regolith-rock profile by analyzing the distribution of natural radionuclides along the profile by high resolution gamma ray spectrometry. The concentrations of radionuclides reflect some mineralogical characteristics of the rock matrix and also more recent events, such as weathering and erosion. The samples were collected in an abandoned limestone mine, in the city of Sapopema, Paraná State, Brazil.

Non-destructive porosity profile measurement of amorphous materials by gamma-ray transmission.

This work presents measurements of the total porosity of TRe soil, sandstone rocks and porous ceramic samples. For determination of the total porosity, the gamma-ray transmission method and the Archimedes method (conventional) were employed. The porosity measurement using the gamma-ray methodology has a significant advantage with respect to the conventional method due to fast and non-destructive determination, and also for supplying results with a greater spatial resolution, in relation to the heterogeneity of the porosity.

Study of variance and covariance terms in linear attenuation coefficient measurements of irregular samples through the two media method by gamma-ray transmission.

The two media method permits the application of Beer's law (Thesis (Master Degree), Universidade Estadual de Londrina, PR, Brazil, pp. 23) for the linear attenuation coefficient determination of irregular thickness samples by gamma-ray transmission. However, the use of this methodology introduces experimental complexity due to the great number of variables to be measured.