Recent Publications

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2021
Krauth, Julian J., Karsten Schuhmann, Marwan Abdou Ahmed, Fernando D. Amaro, Pedro Amaro, François Biraben, Tzu-Ling Chen, Daniel S. Covita, Andreas J. Dax, Marc Diepold, Luis M. P. Fernandes, Beatrice Franke, Sandrine Galtier, Andrea L. Gouvea, Johannes Götzfried, Thomas Graf, Theodor W. Hänsch, Jens Hartmann, Malte Hildebrandt, Paul Indelicato, Lucile Julien, Klaus Kirch, Andreas Knecht, Yi-Wei Liu, Jorge Machado, Cristina M. B. Monteiro, Françoise Mulhauser, Boris Naar, Tobias Nebel, François Nez, Joaquim M. F. dos Santos, José Paulo Santos, Csilla I. Szabo, David Taqqu, João F. C. A. Veloso, Jan Vogelsang, Andreas Voss, Birgit Weichelt, Randolf Pohl, Aldo Antognini, and Franz Kottmann. "Measuring the $\upalpha$-particle charge radius with muonic helium-4 ions." Nature 589 (2021): 527-531. AbstractWebsite
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2020
Reboredo, {Fernando Henrique}, A. Barbosa, {Maria Manuela} Silva, {Maria Luisa} Carvalho, {José Paulo} Santos, {Maria Fernanda} Pessoa, Fernando Lidon, {José C. } Ramalho, and Mauro Guerra. "Mineral Content of Food Supplements of Plant Origin, by Energy Dispersive X-ray Fluorescence: A Risk Assessment." Exposure and Health 12 (2020): 917-927. Abstract

The aim of this study is to evaluate the elemental composition of six food supplements of plant origin, commonly sold in the Portuguese market, by energy dispersive X-ray fluorescence. The presence of arsenic in all the Maca, Ashwagandha, Camu-Camu and Hemp protein samples (except the generic form) is a reason of concern due to the long-term effects of As mainly in its inorganic form. Thus, great caution must be taken on some food supplements, particularly the cases of Moringa from Egypt and Yellow/Xpresso Maca, whose inorganic As concentrations are in line with the upper bound concentration for the 95th dietary exposure according to the European Food Safety Authority which is 0.64 μg/kg bw/day. In what regards Hemp protein, if the supplier’s daily intake recommendation (30 g) is followed, values as high as 1.75 μg/kg bw/day of inorganic As will be consumed, which are dangerously above the upper bound. In this case this specific supplement lot should be removed from the market. Also the consumption of Hemp protein leads to a daily intake of Mn above the Daily Reference Intake (DRI) and Adequate Intakes (AIs) for adults. The contamination of Goji berries by Pb is a reason for concern—organic berries contained 11.3 μg/g while berries derived from conventional agriculture 11.6 μg/g, leading to daily intake doses of 315.3 μg and 324.8 μg, respectively, if the recommended daily intake of 28 g is followed. Our findings point out to an inadequacy of the recommended intakes by the supplier vis a vis the concentrations observed, greatly increasing the risk for public health.

2016
Lopes, A., A. Gabriel, J. Machado, P. Ribeiro, R. Gomes, Jo M. P. o Coelho, C. O. Silva, C. P. Reis, J. P. Santos, and P. Vieira. "Multiple Source Phototherapy in Breast Cancer: A Viability Study." In 9th International Conference on Biomedical Electronics and Devices, 247-250. SCITEPRESS - Science and and Technology Publications, 2016. Abstract
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2015
Guerra, M., P. Amaro, J. Machado, and J. P. Santos. "Modified Binary-Encounter-Bethe Model for Electron Impact Ionization Cross Sections of Highly Charged Ions ." Journal of Physics: Conference Series 635 (2015): 052067. AbstractWebsite
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2014
Tendeiro, Diogo, Gonçalo Lopes, Pedro Vieira, and Jose Paulo Santos. "Monte Carlo simulation of laser beams interaction with the human eye using Geant4." BioMedical Engineering OnLine 13 (2014): 58. AbstractWebsite
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Tendeiro, Diogo, Gonçalo Lopes, Pedro Vieira, and Jose Paulo Santos. "Monte Carlo simulation of laser beams interaction with the human eye using Geant4." BioMedical Engineering OnLine 13 (2014): 58. AbstractWebsite
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Lopes, G., D. Tendeiro, J. P. Santos, and P. Vieira. "Monte Carlo Simulation of Radiation through the Human Retina Using Geant4.", 431-434. Vol. 41. Cham: Springer International Publishing, 2014. Abstract
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Lopes, G., D. Tendeiro, J. P. Santos, and P. Vieira. "Monte Carlo Simulation of Radiation through the Human Retina Using Geant4.", 431-434. Vol. 41. Cham: Springer International Publishing, 2014. Abstract
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2012
Guerra, M., F. Parente, P. Indelicato, and J. P. Santos. "Modified binary encounter Bethe model for electron-impact ionization." International Journal of Mass Spectrometry 313 (2012): 1. AbstractWebsite

Theoretical expressions for ionization cross sections by electron impact based on the binary encounter Bethe (BEB) model, valid from ionization threshold up to relativistic energies, are proposed.The new modified BEB (MBEB) and its relativistic counterpart (MRBEB) expressions are simpler than the BEB (nonrelativistic and relativistic) expressions because they require only one atomic parameter, namely the binding energy of the electrons to be ionized, and use only one scaling term for the ionization of all sub-shells.The new models are used to calculate the K-, L- and M-shell ionization cross sections by electron impact for several atoms with Z from 6 to 83. Comparisons with all, to the best of our knowledge, available experimental data show that this model is as good or better than other models, with less complexity.

Santos, J. P., A. M. Costa, M. C. Martins, F. Parente, and P. Indelicato. "Modeling praseodymium K X-ray lines in an electron beam ion trap." Eur. Phys. J. D 66 (2012): 202. AbstractWebsite

We study the most important processes for the creation of excited states in He-like through C- like praseodymium ions from the ions ground configurations, leading to the emission of K X-ray lines. Theoretical values for inner-shell excitation and ionization cross sections, transition probabilities and energies for the deexcitation processes, are calculated in the framework of the multi-configuration Dirac- Fock method, including QED corrections. Using these calculated values, a theoretical Kα X-ray spectrum is obtained, which is compared to recent experimental data obtained in the Livermore Super-EBIT electron beam ion trap facility.

Santos, J. P., A. M. Costa, M. C. Martins, F. Parente, and P. Indelicato. "Modeling praseodymium K X-ray lines in an electron beam ion trap." The European Physical Journal D 66 (2012): 202. AbstractWebsite

We study the most important processes for the creation of excited states in He-like through C- like praseodymium ions from the ions ground configurations, leading to the emission of K X-ray lines. Theoretical values for inner-shell excitation and ionization cross sections, transition probabilities and energies for the deexcitation processes, are calculated in the framework of the multi-configuration Dirac- Fock method, including QED corrections. Using these calculated values, a theoretical Kα X-ray spectrum is obtained, which is compared to recent experimental data obtained in the Livermore Super-EBIT electron beam ion trap facility.

Guerra, M., F. Parente, P. Indelicato, and J. P. Santos. "Modified binary encounter Bethe model for electron-impact ionization." Int. J. Mass Spectrom. 313 (2012): 1. AbstractWebsite

Theoretical expressions for ionization cross sections by electron impact based on the binary encounter Bethe (BEB) model, valid from ionization threshold up to relativistic energies, are proposed.
The new modified BEB (MBEB) and its relativistic counterpart (MRBEB) expressions are simpler than the BEB (nonrelativistic and relativistic) expressions because they require only one atomic parameter, namely the binding energy of the electrons to be ionized, and use only one scaling term for the ionization of all sub-shells.
The new models are used to calculate the K-, L- and M-shell ionization cross sections by electron impact for several atoms with Z from 6 to 83. Comparisons with all, to the best of our knowledge, available experimental data show that this model is as good or better than other models, with less complexity.

2011
Guerra, M., F. Parente, P. Indelicato, and J. P. Santos. "Modified binary encounter Bethe model for electron-impact ionization." International Journal of Mass Spectrometry Accepted (2011). Abstract

Theoretical expressions for ionization cross sections by electron impact based on the binary encounter Bethe (BEB) model, valid from ionization threshold up to relativistic energies, are proposed.The new modified BEB (MBEB) and its relativistic counterpart (MRBEB) expressions are simpler than the BEB (nonrelativistic and relativistic) expressions because they require only one atomic parameter, namely the binding energy of the electrons to be ionized, and use only one scaling term for the ionization of all sub-shells.The new models are used to calculate the K-, L- and M-shell ionization cross sections by electron impact for several atoms with Z from 6 to 83.Comparisons with all, to the best of our knowledge, available experimental data show that this model is as good or better than other models, with less complexity.

2004
Santos, J. P., and M. F. Laranjeira. Métodos Matemáticos para Físicos e Engenheiros., 2004. Abstract
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1998
Santos, J. P., J. P. Marques, F. Parente, E. Lindroth, S. Boucard, and P. Indelicato. "Multiconfiguration Dirac-Fock calculation of 2s1/2-2p3/2 transition energies in highly ionized bismuth, thorium, and uranium." The European Physical Journal D 1 (1998): 149-163. Abstract

Structure and QED effects for 2s1/2 and 2p3/2 levels are calculated for lithiumlike U89+ trough neonlike U82+, lithiumlike Th87+ trough neonlike Th80+ and lithiumlike Bi80+ trough neonlike Bi73+. The results of the first two sets are compared with recent measurements of the 2s1/2-2p3/2 transition energy in 3 to 10-electron ions. Good agreement with experiment is found for most of the observed lines. Forty-one possible transitions are calculated for each ion in the eight ionization states, in the experimental energy range. Twenty-eight of these transitions have not been observed, nor calculated previously. We also calculate transition rates, branching ratios, excitation and ionization cross sections and confirm that the thirteen experimental observed transitions correspond to the ones with highest relative intensities. However, we find nineteen more transitions that could be measured in a more sensitive experiment.X