Historically accurate reconstructions of Amadeo’s chrome yellows: an integrated study of their manufacture and stability

The subject of this PhD is the study of 19th century yellow chromate pigments, in particular chrome yellow (lead chromate), which has been frequently found in the paintings by the Portuguese Modern painter Amadeo de Souza-Cardoso (1887-1918) and by Vincent Van Gogh (1853-1890). Detailed knowledge of the materials used by artists is fundamental for the understanding of their technique and to place their works in context as well as to determine the state of preservation and authenticity of their work. For this thesis new knowledge was gained through a multidisciplinary approach which combines art technological and conservation science research. This is the first doctoral work that fully explores the Winsor & Newton (W&N) 19th Century Archive Database and provides a unique insight into the company’s choices and workshop practices. W&N had a special concern for the quality and durability of their yellow chromate pigments. A complete evaluation of their 286 production records for yellow chromate pigments was undertaken. The majority of the production records (64%) pertain to different hues of lead chromate. W&N produced essentially three lead chromate pigment types: Lemon/Pale based on mixed crystals of lead chromate and lead sulfate [PbCr1-xSxO4] where x ≤ 0.4; Middle based on pure monoclinic lead chromate [PbCrO4]; and Deep that contains the latter admixed with basic lead chromate [Pb2CrO5]. Production records for the manufacture of barium chromate, BaCrO4 (25%), zinc potassium chromate, 4ZnCrO4·K2O·3H2O (9%), and strontium chromate, SrCrO4 (2%) were also found. Despite the high number of production records, each chromate pigment type is characterised by only one or two main synthetic pathways. W&N’s addition of extenders in their lead chromate pigment formulations, indicates that they were mainly used to adjust pigment properties and not as a means to decrease costs. The reduced number of records found for the production of the light-sensitive Primrose type of lead chromate (a formulation composed of sulfur-rich PbCr1-xSxO4), and strontium chromate, suggests W&N was not manufacturing or selling these pigment formulations on a large scale; more evidence that during the 19th century W&N was committed to primarily selling high quality durable chromate pigments. Pigment reconstructions following the main methods of synthesis were produced for this research and characterised by complementary analytical techniques: Colourimetry, Fibre Optic Reflectance Spectroscopy (FORS), micro-Energy Dispersive X-Ray Fluorescence Spectrometry (μ-EDXRF), X-Ray Diffraction (XRD), Scanning Electron Microscopy with X-ray microanalysis (SEM-EDS), micro-Raman (μ-Raman) and micro-Fourier Transform Infrared (μ-FTIR) spectroscopies. A very good correlation was found between the chemical composition of the pigment reconstructions and historic paint samples from 19th century oil paint tubes and Amadeo’s paintings. This validates their high degree of historical accuracy and attests their use as reference materials for further chemical studies. The lead chromate pigment formulations were made into oil and poly(vinyl acetate) (PVAc) paints and irradiated with a Xenon lamp (λirr > 300 nm) to assess their photostability. The degradation process was followed by the above mentioned techniques and was further studied by Synchrotron Radiation based techniques (μ-XRF, μ-FTIR and μ-XRD). By means of micro X-ray Absorption Near-Edge Structure (μ-XANES), an innovative Light Susceptibility Index (LSI) was developed based on the ratio of the Cr K pre-edge intensity after/before irradiation with a Xenon lamp, which decreases as the quantity of Cr3+ degradation species increases. This index will enable the prediction of the stability of lead chromate pigments in works of art. Three degrees of lightfastness were identified: 1) PbCr1-xSxO4 with 0 ≤ x ≤ 0.4/0.5, 2) PbCr1-xSxO4 with x ≥ 0.4/0.5 and 3) PbCrO4 admixed with a high quantity of the extenders chalk (CaCO3) and gypsum (CaSO4.2H2O). This work demonstrates that the manufacturing conditions, in particular the pH of the production of PbCr1-xSxO4 with 0.4 ≤ x ≤ 0.5, influences their photostability. Most importantly, this is the first work to formulate integrated mechanisms that account for the main causes of colour alteration, and which identifies the crucial role played by the pigment and binder formulations, including their additives. The combined use of the Synchrotron Radiation based techniques allowed access at the micro-scale, to the spatial distribution of the degradation products and intermediaries. This led to the discovery that the reduction of Cr6+ from lead chromate to Cr3+ species is driven by the presence of oxalic acid and/or oxalate compounds. It is proposed that these compounds result from the decomposition of carbonate compounds (present as additives) in acidic media or via decarboxylation of carboxylic acids. These degradation pathways are triggered by the photodegradation of the binder and the degradation rate is deeply dependent on the paint formulation. The presence of calcium oxalate as a degradation intermediary and/or protective patina from light absorption is also discussed in relation to these findings. For the first time, it was possible to identify a Cr3+ degradation compound, a chromium potassium sulfate, CrK(SO4)2·12H2O, by infrared spectroscopy. Finally, it was also possible to determine that no degradation resulting from the reduction of Cr6+ to Cr3+ is currently occurring in Amadeo’s paintings which contrasts with literature reports on the degradation of lead chromate pigments in the work of Van Gogh

Historically accurate reconstructions and characterisation of chrome yellow pigments

Dissertation presented at the Faculty of Sciences and Technology of the New University of Lisbon in fulfillment of the requirements for the Master degree in Conservation ScienceA detailed knowledge of the materials used by artists is essential to unveil their techniques and to place their works in context as well as to establish the most adequate conservation and authentication procedures. Such knowledge arises from reliable documentary sources of technical information contemporary to artists and the preparation of historically accurate reconstructions. Deciphering the words of the past to unravel art technology is far from straightforward, representing one of the most challenging issues within the art conservation field. Chrome yellow pigment belongs to the 19th century artists’ palette. It was enthusiastically used by many artists even when its use was deemed inadvisable. The Portuguese modern painter, Amadeo de Souza-Cardoso, was one of these artists known to have used it. The aim of this work was the manufacture of chrome yellow pigments with as much historical accuracy as possible. This was the first time the Winsor & Newton 19th Century Artists’ Materials Database was systematically explored to support pigment manufacture. The recipes taken from this database were broken down into their relevant steps. This study proposes a correct correspondence between original materials and their current equivalent. A total of 34 pigments and 3 minerals were characterised by EDXRF, Raman, FTIR, XRD and SEM-EDS. Regardless of the recipe or process variations, lead chromate was identified in the majority of the pigments. Depending on the pH, other compounds were also detected. Basic lead chromate was obtained under alkaline conditions, giving rise to an orange hue. Mixed-crystals of lead chromate and lead sulphate were formed under acidic conditions, presenting a lemon hue. All the extenders used, namely calcite, barytes and gypsum, were detected. Notably, cerussite and calcite were also identified even though they were not added as such during the pigment manufacture. Moreover, a comparison with case studies samples was performed. Pure lead chromate and mixed-crystals of lead chromate and lead sulphate were identified in the presence of calcite, barytes and cerussite. Proposals concerning the formulation of these pigments are suggested. A multi-analytical approach proved to be fundamental for the characterisation of all the pigments

Terapia ocupacional y educación inclusiva: una aproximación a la producción científica

[Resumen] OBJETIVOS La educación inclusiva es una práctica efectiva para dar fin a las situaciones de desigualdad social. Constituye un vehículo para el empoderamiento de las comunidades y las capacita para decidir sobre su salud. Esta revisión bibliográfica analiza la producción científica desde Terapia Ocupacional en relación con las prácticas educativas inclusivas. METODOLOGÍA Se realizó una búsqueda bibliográfica en las principales bases de datos de ciencias de la salud, ciencias sociales y educación para responder a los objetivos del estudio. Se han encontrado 16 resultados. RESULTADOS La mayor parte de la producción científica emerge de Estados Unidos. Los temas centrales son: la importancia de incorporar un enfoque cooperativo, el análisis de las percepciones y actitudes hacia la educación inclusiva y ejemplos de prácticas educativas inclusivas. CONCLUSIONES La Educación es una temática transversal que influye en el desempeño ocupacional a nivel global, y favorece el desarrollo y la salud de los niños. La Terapia Ocupacional entiende la escuela como un espacio de oportunidades de participación para asegurar un aprendizaje exitoso.[Resumo] OBXECTIVOS A educación inclusiva é unha práctica efectiva para dar fin ás situación de desigualdade social. Constitúe un vehículo para o emponderamento das comunidades e as capacita para decidir sobre a súa saúde. Esta revisión bibliográfica analiza a produción científica desde T.O. en relación coas prácticas educativas inclusivas. METODOLOXÍA Realizouse unha procura bibliográfica nas principais bases de datos de ciencias da saúde, ciencias sociais e educación para responder aos obxectivos do estudo. Encontráronse 16 resultados. RESULTADOS A meirande parte da produción científica emerxe de Estados Unidos. Os temas centrais son a importancia de incorporar un enfoque cooperativo, a análise das percepcións e actitudes cara á educación inclusiva e exemplos de prácticas educativas inclusivas. CONCLUSIÓNS A educación é unha temática transversal que inflúe no desempeño ocupacional a nivel global, e favorece o desenvolvemento e a saúde dos nenos. A Terapia Ocupacional entende a escola como un espazo de oportunidades de participación para asegurar unha aprendizaxe exitosa.[Abstract] OBJECTIVES Inclusive education is an effective practice to end situations of social inequality. It is a vehicle for the empowerment of communities and enables them to decide about your health. This literature review examines the scientific production from OT regarding inclusive education practices. METHODOLOGY A literature search was conducted in the main database of health sciences, social sciences and education to meet the objectives of the study. Found 16 results. RESULTS Most of the scientific production emerges United States. The central themes are: the importance of incorporating a cooperative approach, analysis of the perceptions and attitudes towards inclusive education and examples of inclusive educational practices. CONCLUSIONS Education is a cross-cutting issue that affects occupational performance globally, and supports the development and health of children. Occupational Therapy understand the school as a space of participation opportunities to ensure successful learning.Traballo fin de grao (UDC.FCS). Terapia ocupacional. Curso 2014/2015

New Insights into Synthetic Copper Greens: The Search for Specific Signatures by Raman and Infrared Spectroscopy for Their Characterization in Medieval Artworks

A systematic investigation of medieval copper green pigments was carried out based on written sources: 21 manuscripts, dating from 50–70 to 1755 AD, were sourced and 77 recipes were selected, translating into 44 experiments. Reconstructions from medieval recipes were prepared and characterized through a multianalytical approach to disclose the original pigment formulation that is often described as verdigris. Based on the results obtained, we propose three main groups of copper green pigments, group 1, in which only Cu(CH3COO)2·H2O is formed; group 2, where this acetate is found together with copper oxalates; group 3, in which atacamite is present as the major green component or as a signature compound. The products formed are in perfect agreement with that predicted by the state-of-the-art research on the mechanisms of atmospheric corrosion of copper. This knowledge, together with our experience on craft recipes to prepare medieval paint materials, allowed us to recover a lost medieval recipe to produce a copper green pigment based mainly on atacamite, a basic copper chloride, which has been recently detected, by Raman and infrared spectroscopy, in artworks ranging from Catalonia and the Crown of Aragon panel painting to Islamic manuscripts.publishersversionpublishe

Predictors of Prevention Failure in College Students Participating in Two Indicated Depression Prevention Programs

The purpose of this study was to identify subgroups of university students with the highest likelihood of remaining at elevated levels of depressive symptoms six months following the receipt of a depressive prevention intervention on the basis of known risk factors and participation in one of two depression prevention programs. Data from a randomized controlled trial evaluating depression prevention among 133 college students with elevated depressive symptoms were analyzed. Participants were randomized to a cognitive-behavioral or relaxation training group preventive intervention. Classification tree analysis showed that older age was the strongest risk factor for persistently elevated depression. Additional risk factors were: (1) for younger students, fewer daily pleasant activities; (2) for those with higher level of pleasant activities, higher level of stressful events; and (3) for those with higher level of stressful events, lower assertiveness. Results offer directions for prevention foci, identify specific subgroups of college students to target for depression prevention efforts, and suggest that research aim to help older, non-traditional students or graduating students manage the transition from college to the work forceThese studies were supported by grant PGIDT05PXIA21101PR from the Directorate General for Research and Development (Counsellery of Innovation, Industry and Trade) of the Xunta de Galicia (Spain)S

Defining the first preventive conservation guidelines for hand-painted magic lantern glass slides

The authors acknowledge the support of the Portuguese Foundation for Science and Technology (FCT-MCTES), through the doctoral program CORES-PD/00253/2012, for the PhD grant PD/BD/136694/2018 (Ângela Santos), and Research Unit VICARTE (UIDB/00729/2020). This research has benefited from the use of the infrastructure PRISC (Portuguese Research Infrastructure of Scientific Collections). The authors are also grateful to all the institutions and individuals that accepted to participate in the online survey, and to the Portuguese Cinematheque – Museum of Cinema, and National Museum of Natural History and Science of the University of Lisbon for the collaboration with the project "Lanterna Magica – Technology and Preservation of Painted Glass Slides for Projection with Magic Lanterns". The authors would also like to acknowledge for the relevant comments of the reviewers that significantly contributed to the improvement of the manuscript.This article intends to define and make available guidelines for the preventive conservation of hand-painted glass slides for magic lanterns, the first optical instruments for the projection of images, invented in the 17th century. For this purpose, around 300 hand-painted glass slides from the Portuguese Cinematheque - Museum of Cinema (CP) and Nacional Museum of Natural History and Science of the University of Lisbon (MUHNAC), were studied in terms of representativity in these collections, discursive genre, type of construction or movement mechanism, state of preservation and degradation problems. A survey was designed and distributed to institutions across the globe aiming for an overview of the formal characteristics of the collections of magic lantern slides and the preventive and interventive conservation measures undertaken. The guidelines are focused on the environmental conditions (temperature, relative humidity, and light), fine particles and pest control, storage and display conditions and materials, as well as handling. Recommendations on performative projections or demonstrations are also provided.publishersversionpublishe

Aislamiento, selección e identificación de actinomicetos, bacterias fotosintéticas no sulfurosas y bacterias ácido lácticas con potencial biofertilizante, a partir de suelos asociados al cultivo de plátano en la Costa Atlántica Colombiana

El cultivo de plátano, requiere fertilización continua y uso de agroquímicos, deteriorando el medio ambiente y aumentando costos en la producción. Una alternativa a esta problemática es el uso de microorganismos nativos, capaces de proveer los nutrientes necesarios y disminuir el uso de agroquímicos. Este trabajo buscaba aislar, seleccionar e identificar Actinomicetos, Bacterias Fotosintéticas y Bacterias Ácido Lácticas con potencial biofertilizante, en suelos asociados al cultivo de plátano en la Costa Atlántica Colombiana. Se aislaron 30 actinomicetos, 15 bacterias ácido lácticas y 28 bacterias fotosintéticas no sulfurosas. Estos aislamientos presentaron actividad solubilizadora de fosfato, fijadora de nitrógeno, degradadora demateria orgánica y antagonista de patógenos, adicionalmente los aislamientos fueron identificados molecularmente por secuenciación del gen 16S rRNA. En conclusión los suelos de los municipios muestrados poseen microorganismos con potencial capacidad promotora de crecimiento vegetal. / Abstract. Plantain production need fertilization continuos and use of agrochemicals, their deteriorating the environment and increasing production cost. An alternative to this problem is the use of native microorganisms capable of providing the necessary nutrients for reduce the use of agrochemicals. This study sought to isolate, select and identify actinomycetes, photosynthetic non sulfur bacteria and acid lactic bacteria with potential biofertilizer in soils associated with the cultivation of plantain in the Atlantic Coast Colombian. 30 actinomycetes, 15 acid lactic bacteria and 28 photosynthetic non sulfur bacteria were isolated. The isolated presented phosphate solubilization activity, nitrogen fixing, antagonism against pathogens, additional isolates were molecular identified by 16S rRNA gene sequencing. In conclusion the soils sampled have microorganisms with potential plant growth promoters.Maestrí

Factorial structure and psychometric properties of the spanish version of the Pittsburgh sleep quality index in non-professional caregivers

Although sleep issues are among the symptoms commonly experienced by the nonprofessional caregiver population, and the Pittsburgh Sleep Quality Index (PSQI) is the most widely used instrument for the assessment of sleep quality, this has not been validated specifically for this population. The objective of this study was to analyze the factorial structure and psychometric properties of the Spanish version of the PSQI in a sample of Spanish non-professional caregivers. Trained clinical psychologists assessed sleep quality using the PSQI, as well as caregiver burden and psychological distress in 201 non-professional caregivers (87.1% female, Mage = 56.2 years). The internal consistency of the PSQI was 0.75. The two-factor model (Sleep quality and Disturbances) had an acceptable fit to the data, was found to be superior to the one-factor model, and more parsimonious than the three-factor model. There was a significant correlation between the PSQI and caregiver burden, as well as between the PSQI and psychological distress (p < 0.001 in all cases). A total score 9 allowed the identification of caregivers with possible anxiety and depression disorders (sensitivity 70.5%, specificity 71.9%). The results show that the PSQI is a reliable and valid instrument for the assessment of sleep quality in caregiversThis research was funded by a Spin-off of the University of Santiago de Compostela (Santiago de Compostela, Spain) “Xuntos. Psychological and Psychiatric Care” (2019-CE081-6)S

Acyl homoserine lactone-mediated quorum sensing in the oral cavity: a paradigm revisited

Acyl homoserine lactones (AHLs), the quorum sensing (QS) signals produced by Gram-negative bacteria, are currently considered to play a minor role in the development of oral biofilm since their production by oral pathogens has not been ascertained thus far. However, we report the presence of AHLs in different oral samples and their production by the oral pathogen Porphyromonas gingivalis. The importance of AHLs is further supported by a very high prevalence of AHL-degradation capability, up to 60%, among bacteria isolated from dental plaque and saliva samples. Furthermore, the wide-spectrum AHL-lactonase Aii20J significantly inhibited oral biofilm formation in different in vitro biofilm models and caused important changes in bacterial composition. Besides, the inhibitory effect of Aii20J on a mixed biofilm of 6 oral pathogens was verified using confocal microscopy. Much more research is needed in order to be able to associate specific AHLs with oral pathologies and to individuate the key actors in AHL-mediated QS processes in dental plaque formation. However, these results indicate a higher relevance of the AHLs in the oral cavity than generally accepted thus far and suggest the potential use of inhibitory strategies against these signals for the prevention and treatment of oral diseasesThis work was supported by the grant “Axudas do Programa de Consolidación e Estructuración de Unidades de Investigación Competitivas (GPC)” from the Consellería de Cultura, Educación e Ordenación Universitaria, Xunta de Galicia (ED431B2017/53) and by the project INTERREG-POCTEP-0227-CODIGOMAIS-1-E. A.M. was supported by a predoctoral fellowship from the Consellería de Cultura, Educación e Ordenación Universitaria, Xunta de Galicia (ED481A-2015/311)S

Symptoms of Depression, Anxiety, and Stress and Prevalence of Major Depression and Its Predictors in Female University Students

Depression, anxiety and stress are increasingly concerning phenomena in our society, with serious consequences on physical and mental health. The repercussions may be particularly devastating in particular population subgroups, such as female university students. The purpose of this study was to determine the levels of depression, anxiety, and stress and the prevalence of depression and associated factors, in Spanish university women. A cross-sectional study was conducted with a random sample of 871 students from the Santiago de Compostela University (mean age 20.7 years, SD = 2.8). Information was collected on sociodemographic and academic characteristics; symptoms of depression, anxiety, and stress; diagnosis of major depression; optimism, resilience, social support, life engagement, and five personality domains, using validated instruments. Of the participants, 18.1%, 22.8% and 13.5% presented with severe/very severe levels of depression, anxiety and stress, respectively. A total of 12.9% had major depression. Higher life engagement was associated with lower risk of depression (OR = 0.92, 95% CI 0.87–0.98), while higher levels of neuroticism (OR = 1.20, 95% CI, 1.12–1.28) and openness to experience (OR = 1.08, 95% CI, 1.02–1.14) were associated with greater risk. These findings reveal an alarming percentage of female university students who experience major depression and severe/very severe stressThis study was funded by the University of Santiago de Compostela (2019-PU005)S