Sofia Pessanha

Sofia Pessanha
Universidade NOVA de Lisboa | NOVA · LIBPhys-UNL

PhD

About

104
Publications
12,234
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1,035
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Additional affiliations
January 2015 - March 2017
Universidade NOVA de Lisboa
Position
  • PostDoc Position

Publications

Publications (104)
Article
Full-text available
Background In comparison to organic mercury (MeHg), the environmental inorganic mercury (IHg) can be found in some skin-lightening cosmestics were considered “harmless” for a long time. However, recent studies have shown that long-term exposure to low doses of IHg may affect biological systems. Therefore, this study investigated the effects of IHg...
Article
Background and aim Evaluating the protective effect in human enamel of a fluorinated varnish after enduring a citric acid erosive challenge. Methods An in vitro model was developed considering the intraoral environment, human saliva and acid erosive procedures. The evaluation of the enamel specimens was undertaken through the direct analysis of en...
Article
Full-text available
This work explores the suitability of data treatment methodologies for Raman spectra of teeth using multivariate analysis methods. Raman spectra were measured in our laboratory and obtained from control enamel samples and samples with a protective treatment before and after an erosive attack. Three different approaches for data treatment were under...
Article
Full-text available
The main goal of this study was to identify potential chemical elements present in three types of polymetallic mine waste, stored in the old mine site of São Domingos, located in the Iberian Pyrite Belt, Alentejo, Southern Region of Portugal. This study involves the characterization of potential resources in those mine residues, bearing in mind tha...
Article
The purpose of this in vitro study is to evaluate the efficacy of a commercially available tooth mousse in the remineralization of human enamel in cases of Molar-incisor-hypomineralization (MIH). Treatment protocol with GC Tooth Mousse containing Casein phosphopeptide amorphous calcium phosphate (CPP-ACP) was applied to 12 teeth (4 healthy, 4 hypom...
Article
This contribution describes the study conducted on two painted wooden reliefs created in the early 1970s by Vasko Lipovac, a prominent Croatian contemporary artist. Due to the poor condition in which the artworks were found, it was important to establish a strategy for conservation and long-term preservation. Accordingly, preliminary knowledge abou...
Poster
Full-text available
Objetivos: O presente estudo in vitro teve como objetivo analisar modificações elementares e moleculares em amostras de esmalte durante a realização de um tratamento de hipersensibilidade dentária. Para isso, foram utilizadas técnicas espectroscópicas de Fluorescência de raios X Dispersiva em Energia (EDXRF) para obter informação química acerca da...
Conference Paper
Full-text available
The main goal of this study was to identify potential chemical elements present in three types of polymetallic mine waste, stored in the old mine site of São Domingos, located in the Iberian Pyrite Belt, Alentejo, Southern Region of Portugal. This study involves the characterization of potential resources in those mine residues, bearing in mind tha...
Article
Full-text available
Aluminum (Al) is one of the most found elements in nature in many forms, and human exposure can be quite common. Therefore, it is important to investigate the effects of exposure to Al mainly at low doses and for a prolonged period, in order to simulate human exposure in the periodontium, an important structure for support and protection of the tee...
Article
Background X ray Fluorescence has been essayed as a suitable technique for the elemental quantification of trace element in human tissues, namely comparison of normal and cancerous tissue. However, accurate results depend on a robust quantification approach, namely correct evaluation of the samples’ dark matrix. Methods In order to determine the m...
Article
The heritage left by the Arab world in the history of science is directly related to the innovations in both the manufacturing of paper and the production of ink. Four Moroccan manuscripts dating to the eighteenth century, conserved at the royal library of Rabat, have been analyzed by X-ray diffraction (XRD), energy-dispersive X-ray fluorescence sp...
Chapter
Raman spectroscopy is nowadays regarded as a practical optical method and non-destructive photonic tool, which can be applied in several biomedical fields for analyzing the molecular composition. This technique is considered appropriate for human dental tissues characterization, from caries detection to evaluation of demineralization caused by acid...
Article
In this work, we present a novel application of the full-field energy-dispersive X-ray fluorescence (EDXRF) imaging system based on a MicroPattern Gaseous Detector (2D-THCOBRA) in the cultural heritage field. The detector has an intrinsic imaging capability with spatial resolution of \(400\,{\upmu }\mathrm { m}\ \mathrm {FWHM}\), and is energy sens...
Article
Trace elements are present in minute amounts in the human body but contribute to its proper functioning, by participating in several biological processes. Imbalance of the concentrations of these elements can lead to the development of pathologies, including cancer. As such, the determination of trace element content in tumour tissues and its compa...
Article
In this work, we aim at achieving the most accurate quantitative determination of elements in human tissues by means of X-ray Fluorescence spectrometry using the external calibration approach. A calibration curve built using a set of certified reference materials (CRM) of animal tissue was compared with the one obtained with a set of CRMs of plants...
Article
In this in vitro study, the effect of the application of tooth bleaching products in human enamel was evaluated using polarized Raman microscopy, particle induced gamma-ray emission (PIGE) and Vickers Hardness test. Due to their acidic nature, teeth whitening products are associated with changes in enamel mineralization. Consequently, products have...
Article
Full-text available
The simulation of atomic relaxation relies on data libraries with tabulated partial fluorescence yield values of radiative transitions, commonly derived from the Evaluated Atomic Data Library (EADL). However, recent studies support that the data library EADL could be improved by adopting Scofield's Hartree‐Fock calculations instead of current Scofi...
Article
The C²TN XMS-PIXE system based on a first generation X-ray Microcalorimeter Spectrometer (XMS) having 1.5% relative energy resolution at Si Kα 1.739 keV and 0.5% relative energy resolution at Fe Kα 6.403 keV, became operational in 2008, presaging various developments to emerge from its use and from connected or related but independent advancements...
Article
In-situ monitoring of potentially toxic elements in mining water samples is of special relevance in order to evaluate the environmental impact of abandoned mining activities. However, it is difficult to develop suitable analytical methods for this purpose considering the complexity of mining water samples matrix as well as the limited sensibility o...
Article
This paper reports the results of a multi analytical research undertaken on a mural and on a panel painting altarpiece authored by José de Escovar in 1603, one of the most productive and controversial painters working for Évora Archiepiscopate at the end of the 16th century and beginning of the 17th century. The two paintings are among his first do...
Article
Full-text available
Zinc K‐shell radiative and radiationless transition rates are calculated using the multiconfiguration Dirac–Fock method. Correlation up to the 4p orbital is included in almost all transition rate calculations. Calculated radiative transition rates and transition probabilities are compared with Scofield's Dirac–Hartree–Slater and Dirac–Hartree–Fock...
Article
Moroccan manuscripts heritage preserves valuable information regarding different fields of Arabian history and culture. Despite this fact, analytical studies carried out in Moroccan manuscripts are scarce. In this work, we made use of a multi-analytical methodology to study, for the first time, four illuminated manuscripts from the Royal library of...
Poster
The Energy Dispersive X-Ray Fluorescence technique is employed to identify and quantify the concentration of several major and minor elements in an analyte, in a non-destructive way. One promising application of EDXRF is the analysis of trace element concentrations and of their distribution in biological samples as a complementary method in the dia...
Article
In this work, we compared the accuracy of gold leaves thickness determination using X-ray Fluorescence (XRF) setups for different X-ray excitation sources. The sources used consisted on: a) direct Bremsstrahlung from an Amptek Mini-X X-ray tube with Rh target, b) partially monochromatized radiation of the same X-ray tube using combination of Al and...
Article
In this work, we present the combined use of in situ X ray Fluorescence spectroscopy and Monte Carlo simulation using PENELOPE code for the completely non-invasive determination of gold leaf thickness in artworks using lead white as mordant. The methodology used is based on the detection of different characteristic lines of Pb in the X ray fluoresc...
Article
Full-text available
A set of tattoo inks from a top brand was analysed by means of Synchrotron-based X-ray Fluorescence spectrometry (Sy-XRF), Atomic Absorption spectrometry (AAS) and Raman Spectroscopy to investigate the presence of toxic metals and hazardous substances. Quantitative analysis shows that Cr, Cu and Pb content is above the maximum allowed levels establ...
Article
Full-text available
In this work we address the study of three groups painted by Josefa d' Óbidos (1630–1684) and by her father Baltazar Gomes Figueira (1604–1674). These painters were the most important pair working in the 17 th century in Portugal with a Proto-Baroque style and the materials and techniques used by their workshop are almost unknown. Analytical proced...
Article
In this work, we established a methodology for the analysis and characterization of hydroxyapatite-based materials using X ray Fluorescence. There are several animal hard tissues that can be recognized regarding the relative amounts of hydroxyapatite (HAp) and collagen, using vibrational spectroscopy. The same principle can be applied within dental...
Article
In this work, two gustatory stimulants of salivary secretion (GSSS) were studied using Raman microscopy to evaluate their potential demineralization effect in human enamel samples and proton induced gamma‐ray emission (PIGE) to quantify fluorine uptake. These pharmaceutical products are usually administrated to patients who have revealed xerostomia...
Article
This study was conducted with the purpose of evaluating the demineralization effect of a widely consumed acidic soft drink, Coca‐Cola®, in human enamel. This way, an in vitro model for the daily intake of this beverage was developed taking into account the intraoral environment. The evaluation of the enamel specimens was undertaken considering two...
Article
In this work we demonstrate the suitability of confocal Raman microscopy for the characterisation of carious dental tissues. Samples of enamel and dentine, presenting carious lesions in different stages of progression, were evaluated by comparing the depolarisation ratio of the PO³⁻4 symmetric stretching band at 959 cm" in the different tissues. Bo...
Article
In this work the elemental composition of paper and ink belonging to two paper handwritten documents is compared using non-destructive Energy Dispersive X Ray Fluorescence. The two documents correspond to a real estate sales manuscript dating from 1555 and a more recent copy of the same transaction, of unknown origin. The findings obtained using th...
Article
In this work, we aim at achieving the most accurate quantitative determination of the composition of exoskeletons of bivalves from Tagus estuary with Energy Dispersive X-ray Fluorescence. Samples from the shells of clams ranging from the Bronze Ages to the 16th century A.D. belonging to the Museu Arqueológico de Almada, and also from the shells of...
Article
The purpose of this investigation is to study the adhesive interface created between two types of dentin - sound and affected - and the restorative material by a universal adhesive system (Futurabond M+), according to its two application approaches - etch-and-rinse (ER) and selfetch (SE). To fulfill this purpose, we assess both the degree of conver...
Article
In this work, we present a methodology for the determination of the depth of demineralization in dental enamel caused by extended use of an Over-The-Counter (OTC) whitening product. Teeth whitening is a very common practice in Dentistry, but concerns have been raised regarding the invasiveness of the treatment, especially regarding OTC products, th...
Article
A set of five manuscripts written by Sister Lúcia between 1941 and 1944 were under study. Among them is the one that contains the description of the third part of the Secret of Fátima also known as the Third Secret of Fátima. In this work, a characterization of the paper and the ink used in these documents was achieved using micro-X-ray fluorescenc...
Article
In this study, we investigated the potential of the Geant4 Monte Carlo simulation package for retrieving accurate elemental concentrations from energy dispersive X-ray fluorescence spectra. For this purpose, we implemented a Geant4 code that simulates an energy dispersive X-ray fluorescence spectrometer in a triaxial geometry. In parallel, we also...
Article
The X-ray fluorescence technique is a powerful analytical tool with a broad range of applications such as quality control, environmental contamination by heavy metals, cultural heritage, among others. For the first time, a portable energy dispersive X-ray fluorescence spectrometer was assembled, with orthogonal triaxial geometry between the X-ray t...
Article
Energy Dispersive X-ray imaging can be used in several research fields and industrial applications. Elemental mapping through Energy Dispersive X-ray imaging technique has become a promising method to obtain positional distribution of specific elements in a non-destructive way. To obtain the elemental distribution of a sample it is necessary to use...
Article
In this work, a non-commercial triaxial geometry energy dispersive X-ray Fluorescence (EDXRF) setup and a benchtop μ-XRF system were used to identify postmortem contamination in buried bones. For two of the individuals, unusually high concentrations of Cu and Pb, but also Zn (in one individual) were observed. The pigments of the burial shroud cover...
Article
Over the years, the presence of mercury in amalgam fillings has raised some safety concerns. Amalgam is one of the most commonly used tooth fillings and contains approximately 50% of elemental mercury and 50% of other metals, mostly silver, tin and copper. Amalgam can release small amounts of mercury vapor over time, and patients can absorb these v...
Article
This article reports the preliminary results of a technical and material study carried out on a 17th century panel painting located at the Chapel of the Souls in the main church of Vila Nova da Baronia (30 km away from Évora city, in southern Portugal). This painting is attributed to José the Escovar, a painter that worked for Évora Archiepiscopate...
Article
Full-text available
The richly decorated foral charter attributed by D. Manuel I of Portugal, in 1515, to the village of Setubal, was studied using Energy Dispersive X-ray Fluorescence spectrometry and Raman micro-spectroscopy. An in situ characterization of the pigments used in the production of this masterpiece showed a very different pigment palette choice when com...
Article
In this work, we report the unusual concentration of mercury in the hair of an individual buried in the 18th to mid-19th centuries and the comparison with the elemental composition of other remains from the same individual. Two energy dispersive X-ray fluorescence (EDXRF) setups, one with tri-axial geometry and the second one with micro-beam capabi...
Article
In this paper, we study the performance of a portable energy dispersive X-ray fluorescence spectrometer by making use of different filter configurations at the X-ray tube output. To fulfill this purpose, we systematically investigated how the detection limits (DL) can be improved by applying three different combinations of filters (Al, Cu and Al +...
Chapter
Full-text available
In this work, a non-commercial triaxial geometry energy dispersive X-ray Fluorescence (EDXRF) setup and a benchtop m-XRF system were used to identify postmortem contamination in buried bones. For two of the individuals, unusually high concentrations of Cu and Pb, but also Zn (in one individual) were observed. The pigments of the burial shroud cover...
Article
The aim of this work is to demonstrate the suitability of the commercial benchtop micro X-ray fluorescence (μ-XRF) system M4 Tornado, to evaluate the differences in lead distribution in different bone and tooth structures. Ante-mortem and post-mortem Pb accumulation was also assessed and the lead amount in different tissues was compared. Micro-XRF...
Article
The long-term performance of the conservation-restoration treatment applied in Moroccan libraries has been questioned, to predict and rank the behavior of restored papers under extreme conditions of storage. This study was conducted to assess the effect of aging on the restoration process, in particular the aqueous de-acidification treatment. For t...
Article
An original manuscript of Eça de Queiroz (1845-1900) "The Illustrious House of Ramires", published in 1900, was analyzed using high resolution X-ray Fluorescence imaging. Several words and sentences were canceled, as corrections for later versions. In two cases, however, almost half a page was covered with a new sheet of paper (glued) and rewritten...
Article
The objects of this study are various local charters (cartas de foral, in Portuguese) granted by Dom Manuel I, King of Portugal (1495–1521), which substituted for medieval ones and were intended to achieve an administrative unification. These are luxuriously illuminated manuscripts, and our study aims at obtaining a better understanding of the gild...
Article
“Dinheiros” are the first Portuguese coins, minted with a billon alloy (majority-based copper alloyed with silver). In this work, a set of “dinheiros” from D. Fernando of Portugal was analyzed and the composition of the alloy was compared with other “dinheiros” from previous reigns. Although the coins were in good state of conservation and no activ...
Article
The objects of this study are various local charters (cartas de foral, in Portuguese) granted by Dom Manuel I, King of Portugal (1495-1521), which substituted for medieval ones and were intended to achieve an administrative unification. These are luxuriously illuminated manuscripts, and our study aims at obtaining a better understanding of the gild...
Article
The purpose of this in vitro study is to assess whether the elemental content of tooth enamel is altered when bleaching the teeth with bleaching gel. Because of tooth bleaching growing popularity and to match the public demands, manufacturers increased the range of bleaching products available, changing its presentation, techniques and concentratio...
Article
The purpose of this in vitro study was to assess whether the mineralization degree and elemental content in tooth enamel are altered when bleaching the teeth with two different over-the-counter bleaching gels, exceeding the recommendations of the manufacturer. In order to perform this evaluation, 12 healthy teeth were used, six samples were treated...
Article
Three historical manuscripts, two on parchment (dated 1280 and 1514) and one on paper support (dated 1589–1592), were under study. The three manuscripts were strongly attacked by microorganisms exhibiting dark brownish stains all over the surface except in the adjacent areas to some of the used inks, where a halo around the written text could be ob...
Article
Full-text available
Portable energy dispersive X-ray fluorescence spectrometry (EDXRF) was used in the Alcobaça Monastery, in order to study the chromatic coatings applied to terracotta statues that belong to two seventeenth-century monumental groupings. The main goal of this scientific approach consisted in determining the elemental composition of the constitutive la...
Article
The purpose of this in vitro study is to assess whether the elemental content of P, Ca and Zn in tooth enamel is altered when bleaching the teeth with bleaching gel. In order to perform this evaluation, sound vestibular surfaces of six anterior healthy teeth, extracted for periodontal or orthodontic reasons were used. Cuts were made in order to obt...
Article
Full-text available
The analysis of a Portuguese "papier-mâché" sculpture depicting Saint Anthony is presented in this case study. Several questions were addressed such as the characteristics of the support, pigments used, and artistic technique in order to establish a possible timeline for its production. Qualitative analyses of the cross-sections and of the paper su...
Article
In this work, the thickness of the gold leaf applied in six Japanese folding screens is compared using a nondestructive approach. Four screens belonging to the Momoyama period (~1573–1603) and two screens belonging to the early Edo period (~1603–1868) were analyzed in situ using energy dispersive X-ray fluorescence, and the thickness of the applied...
Article
Full-text available
In this work, we have built a portable X-ray fluorescence (XRF) spectrometer in a planar configuration coupled to a Raman head and a digital optical microscope, for in situ analysis. Several geometries for the XRF apparatus and digital microscope are possible in order to overcome spatial constraints and provide better measurement conditions. With t...
Article
In this work, the thickness of the gold leaf applied in the Manueline foral charter of Murça (illuminated in 1512) will be determined using X-ray fluorescence (XRF). The process of pounding fine gold into leaf is known as goldbeating and has undergone little change since Antiquity. In the frontispiece of the Manueline foral charter of Murça, the ca...
Article
In the illuminated foral charters commissioned by D. Manuel I, King of Portugal (1495-1521), heraldry played a prominent role. In this work, royal emblems corresponding to the third heraldic design, applied to the Charter of Couto de Teixedo, are studied by means of EDXRF, SEM-EDS, micro-Raman, micro-FTIR and HPLC-DAD to characterize the materials...
Conference Paper
Objective: The purpose of this in vitro study is to assess whether the elemental content of Ca, P and Zn in tooth enamel is altered when bleaching the teeth with 10 % carbamide peroxide bleaching gel. Method: Six anterior healthy teeth, extracted for periodontal or orthodontic reasons and preserved in a 0.5% (w/w) chloramine solution for no longe...
Article
The role of X-ray reflectivity, coherent, and incoherent scattering has been studied in light samples. The angular dependence of these processes was evaluated, and the best geometrical settings for X-ray fluorescence spectrometers was studied both for symmetrical and asymmetrical setups. Emphasis is given to biaxial planar geometry rather than tria...
Article
This work focuses on the characterization of the materials used in a Japanese Namban type folding screen. Namban is the art style inspired by the arrival of the southern barbarians or Nambanjin to Japan in 1543, and the commercial trade then initiated. Energy dispersive X ray spectrometry (EDXRF) was used and complemented with Raman spectroscopy. T...
Article
In this work, a multianalytical approach is employed to characterize the materials used in a Namban folding screen that depicts the arrival of the Portuguese to the port of Nagasaki. Portuguese sailors reached Japan in 1543 and initiated what was to be known as the Namban trade. This interaction between Portuguese and Japanese was meticulously reco...