[en] Full text: One of the important characteristics of a scintillator, material used to detect ionizing radiation, is that the light intensity be high enough for the type of desired application. One kind of scintillators studied are those with red emission, which coincides with the maximum detection efficiency of silicon-based photodetectors (Si-PDs). Si-PDs have some advantages over photomultipliers tubes (conventionally used detectors) such as low cost and greater quantum efficiency. The bismuth ion at the 2+ valence (Bi ²⁺) is one of the ions that, in general, gives red emission in the electromagnetic spectrum. It has already been observed that some bismuth-doped phosphates at the 3+ valence (Bi ³⁺) exhibit Bi ²⁺ emission induced by interaction with X-rays [2]. However, this effect has not yet been observed in the LiLaP₄O₁₂ structure. Furthermore, there are reports in the literature that, in co-doped matrices with cerium and bismuth, electron transfer from cerium to bismuth can occur, improving the Bi ²⁺ emission. This suggests a way to increase bismuth-related emission using the co-doping method with cerium and bismuth ions. Therefore, to study whether there is X-ray induced Bi 2+ emission and, if so, it can be potentiated by electron transfer from cerium, into the phosphate structure, we performed photoluminescence measurements on the TGM line at Brazilian Synchrotron Light Laboratory (LNLS). In addition, radioluminescence (RL) and thermoluminescence (TL) analysis were also performed. The results indicate that cerium influences bismuth-related emission. Furthermore, the red emission, characteristic of Bi²⁺, was observed in the RL spectrum. The red emission grew when the concentration of cerium increases in the structure. (author)

[en] Full text: Cardiac regeneration and developments in the diagnosis and treatment techniques for the breast cancer, which include radiotherapy, have been studied to understand more about the destruction of some structures and elemental changes that can occur. One possible complication is the cardiotoxic side effects, which includes arrhythmia, blood pressure alterations, myocardial ischemia, thrombosis or congestive heart failure. The aim of this work is to verify the possibility of using antihypertensive drugs to minimize and/or prevent damage to arteries caused by irradiation. For this study, eighteen Wistar rats were divided into either a control group, a group that received irradiation (IR) or a group that received irradiation and were treated with losartan (IR+L). Using the LEXRF technique, the effects of irradiation and the protective effects of losartan were evaluated through the maps of O, Na, Mg, Fe, and Cu in the coronary arteries of the rats. CARNAÚBA (Coherent X-Ray Nanoprobe Beamline) is the tender-to-hard X-ray nanoprobe under construction at the new Brazilian synchrotron light source SIRIUS. The beamline provides two separated experimental stations, one with sub-micrometer resolution and another with nanometer resolution, to cover various analysis techniques, including X ray fluorescence (XRF). The all achromatic CARNAÚBA optics will covers continuously the energy range from 2 to 15 keV. With this energy range, it will be possible to analyze K-lines of light elements, like phosphorus and sulfur, and also heavier elements, like calcium and zinc. The use of CARNAÚBA beamline will provide both submicrometer spatial resolution and elemental mapping of important elements in coronary artery of rats allowing analyze the tissue in a cellular level. (author)

[en] Full text: Rare earth permanent magnets are of great importance for cutting-edge technologies, such as: energy generation, electronic information, home appliances, medical treatment, aerospace, among others. The magnets based on Nd-Fe-B stand out, mainly due to their high value of energy product (BH)max, which grants to the miniaturization of technologies in which as higher (BH)max value is, smaller the magnet volume required. In recent years, there has been a growing demand and, consequently, an increase in magnets production and waste generation. One of the challenges in the production of rare earth-based permanent magnets is the recycling of their waste, due to the various challenges inherent to reprocessing techniques. Among all residues, machining sludge residue stands out for being obtained in the mandatory machining step in the production process of sintered magnets based on Nd-Fe-B. The recycling and reuse of machining sludge residues is still a challenge for the magnet industry, due to the lack of knowledge about the characteristics of the residues, such as their structural properties, the level of degradation, which makes it difficult to develop efficient recycling processes. In order to contribute to this research gap, this work aimed to determine the structural characteristics of the machining residue of sintered Nd-Fe-B magnets to enable the evaluation of its use in different recycling technologies. For this purpose, machining sludge residues of sintered Nd-Fe-B magnets and the magnet used for the generation of residues were characterized by Mössbauer spectroscopy, X-ray diffraction and Rietveld refinement method. Mössbauer spectroscopy enabled alpha-iron phases quantification and diffraction patterns contributed to phase quantification analyses, lattice parameters and crystallite size evaluation. By analyzing the Mössbauer spectrum it was possible to determine that the cutting process without the use of a cutting fluid was more aggressive and resulted in higher phase degradation. In another hand, the diffraction patterns analysis showed that the cutting fluid did not affect the parameters of the Nd-Fe-B phase in the machining residue, but it causes a reduction in the crystallite size. (author)

[en] Full text: Persistent luminescent materials present several recent studies on new applications and novel properties. The design of translucent thin-films with persistent luminescent could bring new perspectives for this group of compounds like the application for better solar energy harvest and storage. Here we present a a fast and green method to produce unprecedented translucent blue persistent luminescence films based on Sr₂MgSi₂O₇:Eu²'⁺,Dy³⁺ nanoparticles (250 nm) in hydroxypropyl methylcellulose (HPMC). These HPMC/SMSO composites were designed and optimized in function of their transparency achieving more than 1 h of blue (~475 nm) emission with high translucency (>50%). Since the particles and element distribution is essential to both emission and translucency, the nanofocused X-ray fluorescence mapping was studied at Carnauba beamline under 9656 eV irradiation, detecting Eu (5845 eV) and Dy (6495 eV) L1 fluorescence lines. The X-ray images showed a highly homogeneous distribution of ~5 μm agglomerates without lixiviation of Eu and Dy from the nanoparticles to the polymer. The results indicate that the methodology applied can be expanded to other systems allowing the development of new efficient translucent materials. (author)

[en] Full text: Atomic pair distribution function (PDF) is an attractive technique to analyze X-ray total scattering data. PDF is a powerful characterization tool in material science, and it is an alternative /or complement to conventional X-ray diffraction (XRD) and X-ray absorption spectroscopy. Contrary to XRD that only reflects information about the average structure, PDF analysis allows the detection of small local distortions, bringing information of the local and medium-range order. This method has also been used to study amorphous phases of materials, i.e., those presenting XRD patterns containing broad and low-intensity Bragg peaks. Additionally, it has been useful in structural studies of nanomaterials in which their characteristic sizes limit the proper study by conventional XRD. PDF helps to answer a series of questions regarding local structure, nano-phase detection and quantification, and elucidate anion redox or sensing reactions. The first PDF experiment performed at LNLS was measured at the XDS beamline studying ferroelectric materials with perovskite structure. The following characteristics are mandatory to perform total scattering experiments to be interpreted by PDF: (i) reach high momentum transfer (Q), preferably higher than 20 Å-1; (ii) obtain high resolution in Q and good statistics (high signal-to-noise ratio) for high Q-values; and finally, (iii) use instruments with low background noise, since the data need to have a better signal-to-noise ratio than for Rietveld refinement. The projected beamline, Jatobá, will satisfy all these characteristics. It would reach energy values up to 71 keV, that it is reflected in a Qmax of 37 Å-1 at the 2D detector. We propose to analyze by PDF nanostructures of (Cr,Ti)₂O₃ as a function of temperature and at different atmospheres. With this experiment we expect to elucidate if the surface if affected with the external parameters (temperature and atmosphere) producing nanocluster with distorted structure. (author)

[en] Full text: L-asparagine is a very important amino acid because it is one of the protein-forming amino acids, playing a fundamental role in several biological mechanisms including the formation on the hemoglobin and metabolic control of some cell functions in nerve and brain tissues, itself being used in a variety of treatment of allergic diseases and anemia, as well. Single crystal of L-asparagine monohydrate (LAM), whose molecular formula is C4H8N2O3.H2O, has important physical properties, such as piezoelectricity and nonlinear optical (NLO) properties. In this work, Fe (III)-doped L-asparagine monohydrate crystals were grown by using a slow solvent evaporation method. To order, the effect of Fe doping on the crystal structure of LAM was evaluated through X-ray powder diffraction. Synchrotron radiation based X-ray data acquisition was carried out at diffraction station XRD1 of the Brazilian Synchrotron Light Laboratory (LNLS) using the multi-detector powder diffractometer and cryojet flow for collect X-ray data at 8 distinct temperatures, e.g., 300K, 250K, 220K, 160K, 150K, 140K, 120K and 92 K. Monochromatic X-ray radiation of 8.351 keV was used, with exact wavelength. (author)

[en] Full text: In recent years, experimental silicification of microorganisms proved organic molecules (OMs) preservation under its early entombment and subsequential induration of silica. Thus, sedimentary silica-rich rocks (chert) are considered a record of life in past geological times. The occurrence of OMs has been advocated as evidence of biogenic origin for microfossils founded on Archean chert. Contrarily, such OMs could have also been sourced by abiotic processes. During its precipitation, silica interacts with OMs via adsorption controlled by electrostatic interactions. Such OM-silica composites undergo low-temperature processes (diagenesis), leading to both porosity reduction as the crystallization of more stable SiO₂ polymorphs to become sedimentary rock. Reduction of permeability occurs as the pore throat closes, isolating the porosity network from exogenous fluids and precluding mobility of OMs. However, studies dealing with chert do not address the structural control of silica – porosity system as a potential preservation mechanism for OMs. Thus, we have characterized chert using (U)SAXS, WAXS, Raman, mass spectrometry, TGA, SEM and XRD. Samples were collected from Pacific Ocean´s locations. Samples are composed of microcrystalline quartz spheres supporting a network of sub-micrometrical pores, which have a fractal geometry as SAXS data exhibit a power-law behaviour. GC-MS shows aliphatic carbons suggesting veritable preserved OMs. Raman and MALDI-TOF suggest amide, lipids, and peptide occurrences. OMs are adsorbed onto quartz spheres [TGA data]. Geochemical homogeneity points to the microspheres-pore network as the source of X-ray scattering. (U)SAXS data show spatial heterogeneities suggesting dissimilar diagenetic effects. Accordingly, shifts in I(q) shown by sample 27c could reveal a nanopore control on mineral precipitation. A similar shift was reported for OMs-mediated carbonate precipitation on amorphous silica substrates. (author)

[en] Full text: Manganese acts as a cofactor to central molecules responsible for cell survival and invasion. Our group has described Mn as a relevant aspect of tumor progression [1]. Our study revealed that tumor-bearing mice present altered Mn distribution in the form of Mn-rich niches found in primary tumors and distant organs. X-ray fluorescence (LNLS, CNPEM) was applied to detect and quantify Mn, among other elements, in our samples. Our in vivo data revealed that primary tumors and distant tissues present Mn-rich niches and our in vitro data showed that tumor cells accumulate Mn in culture and secrete this element in exosomes. Interestingly, when analyzing Mn-rich niches in primary tumors, we were able to observe additional elemental changes related to these niches. The element P presented a negative correlation as its concentration decreased at week 5, while Mn was increased compared to weeks 1 and 3 of tumor progression. The elements K, Fe and Cu all presented a positive correlation, increasing alongside Mn in Mn-rich niches. Ca concentration decreased specifically at week 3, but levels at weeks 1 and 5 were similar. Interestingly, Mn-rich niches found in distant organs only presented alterations in Mn levels, all other detected elements presented similar levels between experimental groups. Analysis of extracellular vesicles derived from LLC cells after Mn exposure revealed that these structures do not present any elemental differences when compared to control cells-derived extracellular vesicles, Mn was found to be the only significantly altered element in the vesicles. In conclusion, our data highlight exosomes as a possible route for Mn distribution in cancer. Our perspectives involve the study of Mn transport in tumor cells, specifically, we aim to investigate Mn route from internalization to secretion in exosomes by high-resolution multi-elemental imaging at the new light source, Sirius. (author)

[en] Full text: Partial replacement of clinker in Portland cements (PC) by supplementary cementitious materials, such as blast furnace slag, is beneficial in order to reduce the environmental impact of CO₂ emissions in cement production. However, initial slag hydration is very slow compared to traditional PC, and phase transformation analyses are usually carried out with benchtop equipment that collects diffractograms in approximately one hour. Therefore, the first moments are lost and also require the use of Kapton, which reduces the intensity of peak counting, compromising phase identification. This study aimed at monitoring the hydration of type-III Portland cement in water through in situ DRX using the XRD1/LNLS Line. The diffractograms (Fig. 1) showed the presence of alite, belite, calcite, quartz, periclase and dolomite. Portlandite and hydrotalcite were also identified in the pre-hydrated anhydrous cement. It is possible to see the consumption of gypsum, aluminate and brownmillerite in the first ten minutes and the evolution of ettringite hydration after three hours. The peak of alite had a greater reduction after 11 hours; gypsum, in 18 hours; and brownmillerite, in 20 hours. (author)

[en] Full text: Bone tumours, periodontal diseases, and degenerative cartilage disorders disrupt the daily activities of people. Therapeutic approaches to these pathologic conditions prompted the development of materials that could replace bone and joint tissues. Several materials have been developed for this purpose. In this context, vitreous compositions containing niobium have been investigated to obtain glasses with improved biological properties, and chemical reactivity. Studies incorporating Nb⁵⁺ ions have revealed a reduction in cytotoxicity and induction of significant calcification in normal human osteoblasts. Furthermore, Nb species promote the activity of alkaline phosphatase (ALP), an important factor in the generation of new bone. In the present work, the chemical composition of 58S bioactive glass was slightly modified using Nb₂O₅. For this purpose, a glassy series was prepared by a simple substitution of P₂O₅ for Nb₂O₅, i.e., 60SiO2-36-CaO- (4-x)P₂O₅-xNb₂O₅ in mol% with x=0, 1, 2, 3 and 4%, giving rise to five bioactive glass compositions: 58SN0, 58SN1, 58SN2, 58SN3, and 58SN4. All materials were synthesized by a sol-gel method coupled with a self-propagating combustion method for preparing bioactive glass nanoparticles with high structural homogeneity developed in our research group. The morphology and chemical composition were investigated by SEM-EDS while the textural properties and surface area were investigated via BET analysis. The microstructure of 58S was investigated using some physical properties, infrared and Raman spectroscopies. The results show the presence of glassy nanoparticles with high porosity, chemical composition similar to nominal and a microstructure with high homogeneity, characterized by the presence of NbO₆ octahedrons replacing the SiO₄ tetrahedra in the glass backbone. Complementary analyzes by XAFS spectroscopy may be carried out in the future in order to obtain more information about the short range order of these bioactive glasses. (author)