Artículos (Física Aplicada III)

URI permanente para esta colecciónhttps://hdl.handle.net/11441/10859

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Probing Dust in the MWC 480 Disk from Millimeter to Centimeter Wavelengths
(2026) Shi, Yangfan; Long, Feng; Macías, Enrique; Herczeg, Gregory J.; Pinilla, Paola; Andrews, Sean M.; Toci, Claudia; Liu, Yao; Física Aplicada III; National Natural Science Foundation of China; UK Research and Innovation. UKRI. (United Kingdom); Ministry of Education of Taiwan
We present deep, high-resolution (∼100 mas) Karl G. Jansky Very Large Array Ka-band (9.1 mm) observations of the disk around MWC 480 and infer dust properties through a combined analysis with archival Atacama Large Millimeter/submillimeter Array data at 0.87, 1.17, 1.33, and 3.0 mm. The prominent dust ring at 95 au (B95) is detected at 9.1 mm for the first time, while the faint outer ring at 160 au is not revealed. Through nonparametric visibility modeling, we identified two new annular features: a plateau within 20–50 au across all wavelengths, and a shoulder exterior to the B95 ring at 0.87, 1.17, and 1.33 mm, consistent with signatures of planet–disk interaction. We find that the width of the B95 ring remains constant across wavelengths, suggesting that fragmentation dominates over radial diffusion or that unresolved substructure is present within the ring. Resolved spectral modeling yields two families of dust solutions that reproduce the observations equally well: compact grains or highly porous (90%) grains, with carbonaceous components dominated by refractory organics or amorphous carbon, respectively. The inferred maximum grain sizes peak at the locations of the two rings and reach centimeter within the B95 ring. The total dust masses are 860 +95-78 M/ 1500 +440 -330 M (large/small-grain solution in inner disk) and 230 +14-13 M for the two dust mixtures. The B95 ring alone contains 100 +5-5 M and 43 +2-2 M, respectively, sufficient to assemble the cores of giant planets. Finally, we highlight the power of broadband, multiwavelength observations in placing better constraints on dust composition and porosity in protoplanetary disks.
Demonstration of Super-X divertor exhaust control for transient heat load management in compact fusion reactors
(Nature Portfolio, 2025-09-05) Kool, B.; Verhaegh, K.; Derks, G. L.; Wijkamp, T. A.; Koenders, J. T.W.; Lonigro, N.; McArdle, G.; Vincent, C.; Lovell, J.; Henderson, S. S.; Federici, F.; Brida, D.; Reimerdes, H.; Osborne, N.; van Berkel, M.; The EUROfusion Tokamak Exploitation Team; The MAST-U team; Ayllón Guerola, Juan Manuel; Cruz Zabala, Diego José; Chen, H.; Domínguez-Palacios Duran, Jesús José; Doyle, Scott James; Galdón Quiroga, Joaquín; García Muñoz, Manuel; Hidalgo Salaverri, Javier; Van Vuuren, Anton Jansen; Mancini, Alessio; Mckay, Kiera Anne; Oyola Domínguez, Pablo; Rivero Rodríguez, Juan Francisco; Romero Madrid, Carlos Francisco; Rueda Rueda, José; Toscano Jiménez, Manuel; Velarde Gallardo, Lina; Viezzer, Eleonora; Física Atómica, Molecular y Nuclear; Física Aplicada III; Ingeniería Mecánica y Fabricación; EUROfusion Consortium; Engineering and Physical Sciences Research Council (EPSRC); Department of Energy. United States
Nuclear fusion could offer clean, abundant energy. However, managing the power exhausted from the core fusion plasma towards the reactor wall remains a major challenge. This is compounded in emerging compact reactor designs promising more cost-effective pathways towards commercial fusion energy. Alternative Divertor Configurations (ADCs) are a potential solution. In this work, we demonstrate exhaust control in ADCs, employing a novel method to diagnose the neutral gas buffer, which shields the target. Our work on the Mega Ampere Spherical Tokamak Upgrade shows that ADCs tackle key risks and uncertainties for fusion energy. Their highly reduced sensitivity to perturbations enables active exhaust control in otherwise unfeasible situations and facilitates an increased passive absorption of transients, which would otherwise damage the divertor. We observe a strong decoupling of each divertor from other reactor regions, enabling near-independent control of the divertors and core plasma. Our work showcases the real-world benefits of ADCs for effective heat load management in fusion power reactors.
Computational modelling of the suppression of optic nerve fibre
(Springer, 2026) Pratiwi, Ariastity Mega; Kekesi, Orsolya; Barriga-Rivera, Alejandro; Suaning, Gregg; Física Aplicada III; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Deutsche Forschungsgemeinschaft / German Research Foundation (DFG); National Health and Medical Research Council
Retinal neuroprostheses aim to restore vision in degenerated retina but are hindered by poor activation selectivity. Suppressing subsets of optic nerve fibres based on diameter may improve selectivity by filtering superfluous activations. This study evaluates frequency-induced neuromodulation (FIN) using sinusoidal waveforms to achieve diameter-selective suppression. Computational models of retinal ganglion cells (RGCs) and optic nerve fibres (1.4, 2.8, and 4.3 μm) were subjected to sinusoidal currents from 10 to 10,000 Hz. The range of optic nerve fibre diameters was chosen to represent the optic nerve fibre population in rats. FIN could selectively filter action potential conduction, with the highest suppression probability at frequencies of 1000 Hz and above. The current amplitude required for suppression was influenced by the diameter of the fibres, the sinusoidal frequency of the FIN waveforms, and the ON-OFF typing of the RGC. It was observed that the membrane potential upstream of the FIN application site influenced the response to FIN. Selective suppression based on the fibre diameter is plausible, whereas selective functional-suppression based on the ON-OFF typing is less plausible owing to the small differences in their respective suppression thresholds. Filtering of this kind may improve the utility of retinal neuromodulation as a treatment to blindness.
Effect of energetic ions on edge-localized modes in tokamak plasmas
(Nature Publishing, 2025-01-06) Domínguez-Palacios, J.; Futatani, S.; García Muñoz, Manuel; Jansen van Vuuren, A.; Viezzer, Eleonora; Gonzalez-Martin, J.; Toscano Jiménez, Manuel; Olaya Domínguez, Pablo; Todo, Y.; Suzuki, Y.; Sanchis, L.; Rueda Rueda, José; Galdón Quiroga, Joaquín; Hidalgo-Salaverri, J.; Chen, H.; Rivero Rodríguez, Juan Francisco; Velarde, L.; the ASDEX Upgrade Team; the EuroFUSION MST1 Team; Cruz Zabala, Diego José; Física Atómica, Molecular y Nuclear; Física Aplicada III; Ingeniería Mecánica y Fabricación
The most efficient and promising operational regime for the International Thermonuclear Experimental Reactor tokamak is the high-confinement mode. In this regime, however, periodic relaxations of the plasma edge can occur. These edge-localized modes pose a threat to the integrity of the fusion device. Here we reveal the strong impact of energetic ions on the spatio-temporal structure of edge-localized modes in tokamaks using nonlinear hybrid kinetic–magnetohydrodynamic simulations. A resonant interaction between the fast ions at the plasma edge and the electromagnetic perturbations from the edge-localized mode leads to an energy and momentum exchange. Energetic ions modify, for example, the amplitude, frequency spectrum and crash timing of edge-localized modes. The simulations reproduce some observations that feature abrupt and large edge-localized mode crashes. The results indicate that, in the International Thermonuclear Experimental Reactor, a strong interaction between the fusion-born alpha particles and ions from neutral beam injection, a main heating and fast particle source, is expected with predicted edge-localized mode perturbations. This work advances the understanding of the physics underlying edge-localized mode crashes in the presence of energetic particles and highlights the importance of including energetic ion kinetic effects in the optimization of edge-localized mode control techniques and regimes that are free of such modes.
Bilateral retinal implants for improving visual restoration: a simulated bionic vision study
(Springer, 2026) Rodríguez Míguez, Pablo; Soria Ramón, Pablo; Barriga-Rivera, Alejandro; Física Aplicada III; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Agencia Estatal de Investigación. España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); Universidad de Sevilla
Degenerative diseases of the retina produce a severe deterioration in visual perception. Visual prostheses enable partial vision restoration by eliciting phosphenes (perceived spots of light) through electrical stimulation. By using augmented reality (AR) to simulate bionic vision (SBV), this study aims to provide insights on the potential benefits of bilateral retinal implants. While monocular implants have been extensively studied, research on binocular implants remains limited. Twenty-four volunteers participated in this study, and were divided into two groups, SBV-monocular and SBV-binocular groups; both experienced phosphene-based visual simulations of the scene using 120 phosphenes per implant. A control group perceived the scene directly through the cameras of the AR headset. Participants completed five tasks to assess their orientation, mobility, and pattern recognition capacities. SBV-binocular subjects outperformed in spatial perception and mobility tasks (p-value < 0.05), but not in pattern recognition tasks. All SBV groups perform significantly worse than the control group. The findings suggest that the bilateral implants’ enhanced field of view and stereoscopic depth cues afforded by bilateral implants were shown to support hand-eye coordination and spatial navigation tasks. However, relevant benefits were not demonstrated over monocular implants in detecting fine details in static tasks. This may be attributed to the absence of vergence control, the capacity to shift phosphene position in response to natural eye movements, in the bilateral configuration.
Feasibility of a new GRT setup for the analysis of quaternary metal alloys with radioactive gamma sources
(Elsevier, 2025-11) Moreno-Soto, Javier; Ager Vázquez, Francisco José; Paúl Escolano, Antonio; Gómez Tubío, Blanca; Ortega-Feliú, Inés; Ferreti, Marco; Respaldiza Galisteo, Miguel Ángel; Física Aplicada I; Ingeniería y Ciencia de los Materiales y del Transporte; Física Aplicada III; Física Atómica, Molecular y Nuclear; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; European Union (UE); RNM138: Física Nuclear Aplicada; TEP973: Tecnología de Polvos y Corrosión
Analysing archaeological artefacts made from metallic alloys is often challenging due to the impracticality of sample collection. Traditional non-invasive surface techniques, such as X-ray fluorescence (XRF), electron probe microanalysis (EPMA), scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDX), and particle-induced X-ray emission (PIXE), among others, may yield misleading results if the objects are affected by corrosion or enrichment effects. Consequently, these techniques need to be complemented with others to gain a precise understanding of alloy composition. Gamma-ray transmission (GRT) is a non-destructive technique that can reveal the bulk composition of a sample. A new GRT setup has been developed to measure the concentrations of binary, ternary, and quaternary alloys using three sources simultaneously, reducing the measurement time. Alloys made in the laboratory were analysed with XRF, showing notable composition discrepancies in some cases, while the GRT results agreed with the expected composition. This innovative GRT setup, with its potential to significantly contribute to future archaeological investigations of alloy compositions, proves to be a valuable tool for analysing metallic artefacts.
The survivorship bias of protoplanetary disc populations: Internal photoevaporation causes an apparent increase in the median total disc mass with time
(EDP Sciences, 2025-07) Malanga, Lorenzo Alessio; Rosotti, Giovanni P.; Lodato, Giuseppe; Somigliana, Alice; Manara, Carlo Felice; Toci, Claudia; Testi, Leonardo; Física Aplicada III; European Union; Fondazione Cariplo; European Southern Observatory
The evolution of protoplanetary discs has a substantial impact on theories of planet formation. To date, neither of the two main competing evolutionary models – namely, the viscous-photoevaporative paradigm nor the MHD winds model – has been ruled out by observations. Due to the high number of sources observed by large surveys, population synthesis is a powerful tool to distinguish the evolution mechanism in observations. We explored the evolution of the mass distribution of synthetic populations under the assumption of turbulence-driven accretion and dispersal caused by internal photoevaporation. We find that the rapid removal of light discs often results in an apparent increase in the median mass of the surviving disc population. This occurs both when disc properties are independent of each other, and when typical correlations between these quantities and stellar mass are assumed. Furthermore, as MHD wind-driven accretion rarely manifests the same features, this serves as a signature of the viscous-photoevaporative evolution when dispersal proceeds from the inside out. Therefore, we propose the evolution of median mass as a new method to distinguish this model in observed populations. The median accretion rate, which decreases with time, does not show this survivorship bias. Moreover, we introduce a new criterion that estimates disc lifetime as a function of initial conditions and an analytical relation to predict whether internal photoevaporation triggers an inside-out or an outside-in dispersal. We verify both analytical relations with numerical simulations.
The Lyon Mint in the Roman Tomares Hoard (Seville): Some Considerations on Its Metallic Composition Determined by XRF
(Willey, 2025-06-15) Pliego Vázquez, Ruth; Gómez-Tubio, Blanca María; Alcaide Ramírez, María; Scrivano, Simona; Respaldiza Galisteo, Miguel Ángel; Física Atómica, Molecular y Nuclear; Prehistoria y Arqueología; Física Aplicada III; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Universidad de Sevilla
Multi-technique computational assessment of fluoride uptake in enamel using PIGE, NEXAFS, and Raman spectroscopy
(2025-05-12) Pessanha, Sofia; Fortes, António; Lopes, Marta B.; Guilherme Buzanich, Ana; Ortega-Feliú, Inés; Respaldiza Galisteo, Miguel Ángel; Gómez-Tubio, Blanca María; Silveira, João; Física Aplicada III; Física Atómica, Molecular y Nuclear; Fundação para a Ciência e a Tecnologia. Portugal
The uptake of fluoride in the enamel matrix is an effective strategy to prevent demineralization and caries formation. In this study a comprehensive methodology is developed to evaluate and understand the uptake of fluoride in human enamel. Twenty-six healthy anterior teeth were sectioned in half; one half remained untreated, while the other was treated with 50 mg mL−1 NaF (equivalent to 22.6 mg of fluoride) through three 1-minute applications over a 12-day period, following the manufacturer's guidelines. Fluoride uptake was quantified with particle-induced gamma-ray emission (PIGE), revealing an average increase of 160% in treated samples. The formation of calcium fluoride (CaF2) and fluorapatite-like structures was confirmed through near edge X-ray absorption fine structure (NEXAFS) analysis. Due to the absence of reference spectra for hydroxyapatite, fluorapatite, and calcium fluoride, finite difference method near edge structure (FDMNES) simulations were employed to computationally model the fluorine K-edge and the Ca L-edge spectra. Density functional theory (DFT) and time-dependent DFT (TDDFT) approaches were applied to enhance spectral accuracy, enabling a refined comparison with experimental data. To establish a rapid and laboratory-based screening technique, Raman microscopy was used to analyze fluoride-treated and untreated samples. Spectral data were evaluated using both full-spectrum analysis and specific spectral features, including band intensity, full-width at half maximum (FWHM) of Raman peaks, and phosphate symmetric stretching depolarization ratios. Furthermore, machine learning algorithms were applied to classify treated and untreated enamel samples. The random forest classifier demonstrated strong predictive performance, successfully distinguishing fluoride-treated samples. This methodological approach provides an effective framework for analyzing fluoride uptake in enamel, potentially guiding future preventive dentistry strategies.
Direct measurement of the electric field induced by a transcranial magnetic stimulator
(Institute of Electrical and Electronics Engineers, 2023-05-15) Freire Rosales, Manuel José; Bernal Méndez, Joaquín; Gutiérrez-Muto, Ane Miren; Oliviero, Antonio; Tornero, Jesús; Electrónica y Electromagnetismo; Física Aplicada III
This work proposes a simple method to carry out in the laboratory a direct measurement of the primary solenoidal electric field that transcranial magnetic stimulation (TMS) coils generate in the brain. This method avoids indirect estimation of this electric field from measurements of magnetic fields and, at the same time, overcomes the difficulty posed by the presence of a dominant conservative electric field, also produced by the coil. This conservative electric field, which is removed in practice by human tissue, is eliminated in the proposed measurement method by using a simple setup that does not require the introduction of the measurement probe inside a conducting solution resembling the human tissue. The proposed measurement method allows for measuring the primary solenoidal electric field in front of the coil in the air. This method has been validated by comparing the results of electromagnetic simulation with the measurement of the magnetic field and the nonconservative electric field produced by a commercial TMS coil.
Coulomb Driven Electro-Convection within Two Stacked Layers of Miscible Dielectric Liquids †
(Multidisciplinary Digital Publishing Institute (MDPI), 2024) Traore, P.; Pérez Izquierdo, Alberto Tomás; Mondal, S.; Bhattacharya, A.; Vázquez González, Pedro Ángel; Yan, Z.; Electrónica y Electromagnetismo; Física Aplicada III; Labex Interactifs. Francia; Ministerio de Ciencia e Innovación (MICIN). España
This article investigates the behavior of two parallel layers of different miscible dielectric liquids enclosed and sandwiched between two electrodes. By applying an electric potential to one electrode while grounding the other, electro-convection occurs when the electric Rayleigh number exceeds a critical value, setting the fluid into motion and resulting in rapid mixing between the two liquids. A numerical model is developed to account for the varying ionic mobility and permittivity of the two liquids, considering their evolution based on the relative concentration field. The simulations confirm that electro-convection significantly enhances the mixing between the two liquids, as expected. Additionally, intriguing ripples are observed near the initial interface during the early stages of electro-convection instability growth. To explain and describe the flow dynamics in terms of stability analysis, a semi-analytical model is presented. This study provides insights into the mixing behavior and flow dynamics of miscible dielectric liquids under the influence of electro-convection. The findings contribute to a better understanding of the underlying mechanisms and can be valuable for applications such as microfluidics, energy conversion, and mixing processes. Further research is encouraged to explore additional parameters and optimize the control of electro-convection for practical applications.
Compositional and microstructural study of joining methods in archaeological gold objects
(John Wiley and Sons Ltd, 2017-03) Scrivano, Simona; Gómez-Tubio, Blanca María; Ortega-Feliú, Inés; Ager Vázquez, Francisco José; Paúl Escolano, Antonio; Física Atómica, Molecular y Nuclear; Física Aplicada III; Física Aplicada I; Ingeniería y Ciencia de los Materiales y del Transporte; Ministerio de Economía y Competitividad (MINECO). España
This work arises in response to the need to understand the production techniques of pre-roman gold jewels, starting from the systematic characterization of the different methods of metal joining used in antiquity to produce these objects. To meet this requirement, different procedures used in antiquity were reproduced by means of experimental archaeology. These models correspond to three metal-joining methods reported by ancient recipes: solid-state diffusion with copper salt, brazing and autogenous welding. These techniques were studied by different analytical methods in order to characterize them at both compositional and microstructural level (SEM-EDS, metallography, μ-XRF and μ-PIXE). The results obtained show that the solid-state diffusion bonding with copper salt presents a crystal hexagonal structure without phase changes in the joining point, where only a variation in the grain size is observed. At the compositional level, this soldering method is characterized by a local increase in copper concentration and a small decrease in gold content. In contrast, brazing shows a dendritic-porous structure due to the superposition of the soldering alloy and the crystal structure of the original foils. Besides, the compositional analysis revealed an increment of silver and copper concentrations and a simultaneous reduction of gold concentration. Finally, in the autogenous welding, no changes at the microstructural and compositional levels were observed. The results obtained have also demonstrated the usefulness of a portable μ-XRF system for the in-situ characterization of ancient jewels.
Combining XRF and GRT for the analysis of ancient silver coins
(Elsevier, 2016-05) Ager Vázquez, Francisco José; Gómez-Tubio, Blanca María; Paúl Escolano, Antonio; Gómez-Morón, A.; Scrivano, Simona; Ortega-Feliú, Inés; Respaldiza Galisteo, Miguel Ángel; Física Atómica, Molecular y Nuclear; Física Aplicada I; Física Aplicada III; Ingeniería y Ciencia de los Materiales y del Transporte; Ministerio de Economía y Competitividad (MINECO). España
Archaeological silver-copper alloys are usually affected by silver enrichment of the near surface layers, either intentional or fortuitous. In previous studies we have shown that surface composition of archaeological bronzes and leaded copper coins obtained by XRF can be corrected by means of gamma-ray transmission (GRT) to obtain the bulk composition. In the present work, we have studied the applicability of this method to silver-copper alloys and established the most suitable conditions for the GRT correction calculation. The analysis of the microstructure of the core and the corrosion layers of a set of silver roman coins shows that copper could be leached from the surface during corrosion and cleaning treatments, resulting in an apparent silver surface enrichment. After the correction calculations by GRT method, the concentrations of the major elements, Ag and Cu, were found to be in good agreement with the bulk composition obtained by direct analysis of the cut cross-sections of the coins. The GRT method shows to be a useful tool to study metal artefacts having a surface composition modified by corrosion or cleaning treatments.
Wigner representation for entanglement swapping using parametric down conversion: the role of vacuum fluctuations in teleportation
(Taylor & Francis, 2015-03-12) Casado Rodríguez, Alberto; Guerra, Santiago; Plácido, José; Física Aplicada III
We apply the Wigner formalism of quantum optics in the Heisenberg picture to study the role of the zeropoint field fluctuations in entanglement swapping produced via parametric down conversion. It is shown that the generation of mode entanglement between two initially non-interacting photons is related to the quadruple correlation properties of the electromagnetic field, through the stochastic properties of the vacuum. The relationship between the process of transferring entanglement and the different zeropoint inputs at the non-linear crystal and the Bell-state analyser is emphasized.
Spectrum of the parametric down converted radiation calculated in the Wigner function formalism
(Springer, 2001-01) Casado Rodríguez, Alberto; Marshall, Trevor W.; Risco, Ramón; Santos, Emilio; Física Aplicada III
We continue the study of parametric down conversion within the framework of the Wigner representation, by using a Maxwellian approach developed in a recent paper [A. Casado et al., Eur. Phys. J. D 11, 465 (2000)]. This gives a mechanism, inside the crystal, for the production of the down-converted radiation. We obtain the electric field to second order in the coupling constant by using the Green's function method, and compare our treatment with the standard Hamiltonian approach. The spectrum of the down-converted radiation is calculated as a function of the parameters of the nonlinear crystal (in particular the length) and the radius of the pumping beam.
Wigner representation for experiments on quantum cryptography using two-photon polarization entanglement produced in parametric down-conversion
(IOP Publishing, 2008-02-28) Casado Rodríguez, Alberto; Guerra, Santiago; Plácido, José; Física Aplicada III
In this paper, the theory of parametric down-conversion in the Wigner representation is applied to Ekert's quantum cryptography protocol. We analyse the relation between two-photon entanglement and (non-secure) quantum key distribution within the Wigner framework in the Heisenberg picture. Experiments using two-qubit polarization entanglement generated in nonlinear crystals are analysed in this formalism, along with the effects of eavesdropping attacks in the case of projective measurements.
Rome teleportation experiment analysed in the Wigner representation: the role of the zeropoint fluctuations in complete one-photon polarization-momentum Bell-state analysis
(Taylor & Francis, 2018-10-07) Casado Rodríguez, Alberto; Guerra, Santiago; Plácido, José; Física Aplicada III
The Wigner representation of parametric down conversion in the Heisenberg picture is applied to the study of the Rome teleportation experiment. We investigate the physical meaning of the zeropoint inputs at the different areas of the experimental set-up. In particular, we establish a quantitative relationship between the zeropoint sets of modes that are needed for the preparation of the quantum state to be teleported, the idle channels inside the one-photon polarization-momentum Bell-state analyser, and the possibility of performing teleportation of a polarization state with certainty.
Wigner representation for polarization-momentum hyperentanglement generated in parametric down-conversion, and its application to complete Bell-state measurement
(Springer, 2014-11-06) Casado Rodríguez, Alberto; Guerra, Santiago; Plácido, José; Física Aplicada III
We apply the Wigner function formalism to the study of two-photon polarization-momentum hyperentanglement generated in parametric down-conversion. It is shown that the consideration of a higher number of degrees of freedom is directly related to the extraction of additional uncorrelated sets of zeropoint modes at the source. We present a general expression for the description of the quantum correlations corresponding to the sixteen Bell base states, in terms of four beams whose amplitudes are correlated through the stochastic properties of the zeropoint field. A detailed analysis of the two experiments on complete Bell-state measurement included in [Walborn et al., Phys. Rev. A 68, 042313 (2003)] is made, emphasizing the role of the zeropoint field. Finally, we investigate the relationship between the zeropoint inputs at the source and the analysers, and the limits on optimal Bell-state measurement.
Palladium analysis in gold items from Punic jewellery (Cádiz, Spain)
(Elsevier, 2020-02) Ortega-Feliú, Inés; Gómez Tubio, Ana María; Scrivano, Simona; Ager Vázquez, Francisco José; Bandera Romero, María Luisa de la; Respaldiza Galisteo, Miguel Ángel; Física Aplicada III; Física Aplicada I; Física Atómica, Molecular y Nuclear; Ministerio de Ciencia e Innovación (MICIN). España; Universidad de Sevilla; RNM138: Física Nuclear Aplicada
Some years ago a group of jewels from the Museum of Cádiz (South Spain) was analysed by micro-PIXE (Particle Induced X-ray Emission) at Centro Nacional de Aceleradores (Sevilla). During this work two similar spiral earrings happened to have significant amounts of palladium in their composition, up to 0.7 wt%, and some hypotheses about the provenance of this palladium-bearing gold were exposed. Many similar gold earrings from the same location and time are kept in the museum, some of them permanently exhibited in the showcases. Now, by means of a portable X-ray spectrometer device, especially designed for the analysis of gold jewels, a second campaign has been accomplished to study the rest of the jewels kept at the museum. This time the equipment was moved to the museum instead of taking the gold items to the laboratory, facilitating the analysis of the samples in the showcases and reducing the costs. A total of 94 jewels have been studied and 24 of them contained palladium up to 1.1 wt%. Copper content was below 2.5 wt% in most of the cases. X Ray Fluorescence technique was employed for this study. A filter of 20 μm of Zn was used in the detector to enhance the detection of palladium, and other potential platinum group elements, by absorbing the Au-Lα emission line. The effects of this method in the quantification was also compared in this work, finding higher uncertainties with the use of the filter, but demonstrating the convenience of its use to discriminate the Pd-Kα line from the sum peaks of the very intense gold lines.
Fluoride exposure duringintrauterine and lactation periods promotes changes in the offspring rats' alveolar bone
(Elsevier, 2022-11) Ferreira, Maria Karolina Martins; Souza-Monteiro, Deiweson; Bittencourt, Leonardo Oliveira; Matos-Sousa, José Mário; Chemelo, Victória Santos; Santos, Vinicius Ruan Neves; Nunes, Paula Beatriz Oliveira; Balbinot, Gabriela de Souza; Prado, Alejandro Ferraz; Collares, Fabricio Mezzomo; Ager Vázquez, Francisco José; Ortega-Feliú, Inés; Respaldiza Galisteo, Miguel Ángel; Pessanha, Sofia; Lima, Rafael Rodrigues; Física Aplicada I; Física Aplicada III; Física Atómica, Molecular y Nuclear; RNM138: Física Nuclear Aplicada
The importance of fluoride (F) for oral health is well established in the literature. However, evidence suggests that excessive exposure to this mineral is associated with adverse effects at different life stages and may affect many biological systems, especially mineralized tissues. The purpose of this study was to investigate the effects of F exposure during pregnancy and breastfeeding on the alveolar bone of the offspring since the alveolar bone is one of the supporting components of the dental elements. For this, the progeny rats were divided into three groups: control, 10 mg F/L, and 50 mg F/L for 42 (gestational and lactation periods). Analysis of the quantification of F levels in the alveolar bone by particle-induced gamma emission; Raman spectroscopy to investigate the physicochemical aspects and mineral components; computed microtomography to evaluate the alveolar bone microstructure and analyses were performed to evaluate osteocyte density and collagen quantification using polarized light microscopy. The results showed an increase in F levels in the alveolar bone, promoted changes in the chemical components in the bone of the 50 mg F/L animals (p < 0.001), and had repercussions on the microstructure of the alveolar bone, evidenced in the 10 mg F/L and 50 mg F/L groups (p < 0.001). Furthermore, F was able to modulate the content of organic bone matrix, mainly collagen; thus, this damage possibly reduced the amount of bone tissue and consequently increased the root exposure area of the exposed groups in comparison to a control group (p < 0.001). Our findings reveal that Fcan modulate the physicochemical and microstructural dimensions and reduction of alveolar bone height, increasing the exposed root region of the offspring during the prenatal and postnatal period. These findings suggest that F can modulate alveolar bone mechanical strength and force dissipation functionality.

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