232 research outputs found
Treating Smalt: A Preliminary SEM-EDX Study of the Effects of Aqueous-based Alkaline Conservation Treatments on Smalt in Wall Paintings
Smalt is a blue cobalt-coloured glass pigment used in European wall paintings from the early Renaissance period that became a popular choice for artists due to its unique tone, availability, and ve..
A particular temper: mineralogical and petrographic characterisation of ceramic fabrics with glauconitic inclusions
This paper focuses on the mineralogical and petrographic characterisation of ceramic fabrics rich in glauconitic pellets, found out in a few local productions of European and Mediterranean sites dated from Prehistory to the Middle Ages. The main distinguishing features of glauconitic inclusions are their rounded shape, dark colour and peculiar chemical composition. During the firing – as also evidenced by a few preliminary experimental tests on glauconitic sediments – the pellets change in colour (from green to red or black in thin section) because of the oxidation of divalent iron and their texture becomes more homogeneous, up to the partial or complete vitrification at moderately high temperatures.Dans cet article, on présente la caractérisation minéralogique et pétrographique des pâtes céramiques riches en pellets glauconitiques, trouvées dans quelques productions locales de sites européens et méditerranéens d’age préhistorique à médiéval. Les plus importants éléments discriminants des pellets glauconitiques sont leur forme arrondie, leur couleur rouge ou noire et leur composition chimique particulière. Durant la cuisson, comme quelques tests préliminaires sur sédiments glauconitiques l’ont confirmé, les pellets changent de couleur (de vert à rouge ou noir en lame mince), à cause de l’oxydation du fer bivalent, et leur texture devient plus homogène, jusqu’à la vitrification partielle ou totale à des températures relativement hautes
Chemical characterization of the stained glass window from the rose window, Siena Duomo (Italy, 1288-1289)
[EN] The chemical composition of nine medieval coloured stained glasses from Duomo (Catedral) of Siena, Italy, has been
characterized. They come from the rose window elaborated under the drawing of Duccio di Buoninsegna masterwork (1288-
89 AD). This note explains the results obtained by EMPA, representative of bulk chemistry of several coloured glasses (deep
green, olive green, yellow, purple, pink, deep blue, light blue, red plaqué and also uncoloured), as well as the associated
trace elements (obtained by Induced Coupled Plasma Mass Spectrometry) that represent the chemical fingerprint of these
glasses. The studied samples are sodium-calcium glass (chemical compositions in the range 13-14 wt% Na2O, 56-64 wt%
SiO2, 4 wt% MgO, 9-10 wt% CaO, 2,5-4 wt% K2O); thus of Mediterranean tradition.This fact has been found by our team in
previous studies (stained glasses from the church of Monestir de Pedralbes, Barcelona) for XIV century glass made at least
40 years later. As a general rule, the conservation state of these sodium glasses is good, except for the cohesion of grisaille
to glass mesostase.
This study allowed to identify three glass groups developed from different raw material formulations: a first group is
constituted by deep green, olive green, light blue and yellow glass; a second one comprises by uncoloured, deep purple,
deep blue and pink glass; and finally, the plaqué red glass that shows deeply different composition. Pink and yellow glass
was produced following the traditional recipe compiled by Theophilus, a monk who lived at the beginning of XII century.
This implies a separate process of raw material purification and a careful control of the redox kiln conditions; thus, these
glasses can be considered as traditional or technologically not evolved. The deep blue, light blue and deep purple were
obtained after the artisan dosed addition of a cobalt salt. Olive green and deep green glasses were produced with addition
of copper (together with manganese and iron), previously prepared as a pigment that has as excipient a potassium glass.
The use of potassium glass instead of the sodium glass locally produced strongly suggests that the pigment could be bought
directly from Middle or Northern Europe markets and/or could be a sub-product of copper ore melting. On the other hand,
the production of sodium red ruby plaqué glass, technologically more evolved and comparable to the coeval potassium glass
coming from the Central Europe glass factories, would be outstanding in the XIV century; but we interpret (taking into
account its chemical composition) that was produced later and introduced during the restoration conducted at the end of
XVII century. We can also note the use of well-dosed lead additions in order to increase the lightness and transparency of
coloured glass. Manganese has been a very important element in the Siena workshop glassmaker colour palette achievements.
On the other hand, the trace-element chemical fingerprint of the glass allows arguing what kind of mineral salts were used
as pigments, as well as the way to introduce it in the uncoloured original glass.[ES] Se han caracterizado químicamente una colección de vidrios arquitectónicos coloreados originales del rosetón del Duomo
(catedral) de Siena, Italia, realizados bajo diseño del artista Duccio di Buoninsegna en 1288-89. Esta comunicación expone los
resultados obtenidos mediante el empleo de microsonda electrónica de Castaing (mayoritarios) y espectrometría de masas
con fuente de plasma acoplado inductivamente (ICP-MS, elementos en traza) en vidrios de varios colores (incoloro, verde
oscuro, verde oliva, amarillo, violeta, rosa, azul oscuro, azul celeste, rojo plaqué). Se trata de vidrios sódico-cálcicos (valores
en peso alrededor del 13-14 % de Na2O, 56-64 % SiO2, 4% MgO, 9-10 % CaO, 2,5-4 K2O) de tradición por tanto mediterránea.
Un resultado semejante se encontró precedentemente para vidrios realizados a lo largo del siglo XIV, cuanto menos unos 40
años después (vidriera de la iglesia del Monestir de Pedralbes, Barcelona). En general, el estado de conservación de estos
vidrios es bueno, excepto por lo que se refiere a la adherencia de las grisallas al vidrio base.
El estudio desarrollado ha permitido identificar tres grupos de vidrios desarrollados a partir de formulaciones de diferentes
composiciones: un primer grupo constituido por los vidrios de color verde claro, verde oscuro, azul celeste y amarillo; un
segundo grupo constituido por los vidrios incoloro, violeta, azul oscuro, y malva; y finalmente el vidrio rojo plaqué, de
composición netamente diferente a todos los demás. Desde el punto de vista de la obtención de los colores, cabe destacar que
los datos químicos permiten deducir que el malva y el amarillo han sido elaborados siguiendo la receta tradicional del monje
Theophilus de inicios del siglo XII, utilizando un proceso de purificación especial de las materias primas, y controlando
artesanalmente las condiciones redox del horno; en este sentido, estos vidrios se pueden calificar como tradicionales o
tecnológicamente poco evolucionados. Los colores azul oscuro, violeta y azul celeste se han obtenido mediante la adición de
una misma sal de cobalto en diferentes dosis, y los colores verde oliva y verde oscuro mediante la adición de cobre (junto
con manganeso y hierro), previamente preparados en un colorante que tiene como excipiente un vidrio potásico. Este último
hecho (el empleo de vidrio potásico no usual en los centros productores del área mediterránea) permite suponer que el color
puede haber sido comprado directamente a un fabricante centroeuropeo o que se tratara de un subproducto de fundición
de minerales de cobre. Por su parte, la fabricación del vidrio plaqué, tecnológicamente más complejo y comparable al vidrio
rojo plaqué potásico centroeuropeo contemporáneo indicaría, si fuera original, la incorporación de este proceso tecnológico
al taller local. En opinión de los autores se trata de un vidrio de producción local mucho más tardia, incorporado en la
restauración documentada a finales del siglo XVII. Destaca también, como en Pedralbes, el empleo del plomo para aumentar
la luminosidad y transparencia del vidrio, en dosis variables atendiendo al color del vidrio. Por otro lado hay que señalar que
en Siena el manganeso es un elemento muy importante con el que el fabricante del vidrio jugó intensamente para obtener
la paleta de colores. El análisis de los metales presentes como elementos traza, y de las tierras raras, permite establecer
sólidas hipótesis sobre el tipo de sales minerales empleadas como colorantes y como fueron incorporados al vidrio incoloro
original.Este trabajo se ha podido realizar
en el marco de diferentes proyectos financiados (proyecto
3338 de la Fundació Bosch i Gimpera, UB; acción integrada
hispano-italiana HI2006-0190: La producción y el comercio
del vidrio plano en Europa y en el Mediterráneo Occidental,
entre los siglos XI y XV: un estudio arqueométrico) . La
caracterización geoquímica de los vidrios mediante MSE e
ICP-MS se ha llevado a cabo en los Serveis Científico-Tècnics
de la Universitat de Barcelona (SCT-UB);Peer reviewe
ROCCA cohort study: Nationwide results on safety of Gam-COVID-Vac vaccine (Sputnik V) in the Republic of San Marino using active surveillance
Background: Gam-COVID-Vac is the world's first registered vector vaccine against COVID-19 based on a combination of two heterologous adenoviruses. It was chosen by the Republic of San Marino as the main tool in its vaccination campaign, which started on 25 February 2021. Our aim was to build up on the ROCCA study, focused on the older population, by describing adverse effects following immunisation (AEFIs) rates and characteristics in all age groups for the first time in a real-world context. Methods: An active surveillance study on recipients of at least one dose of the Gam-COVID-Vac vaccine was conducted. Participants were administered online questionnaires through live/phone interviews with physicians, by e-mail or by scanning a QR code at different points in time after the first dose: one week (Q1) one month (Q2), and three months (Q3) between March and August 2021. Findings: Overall, 6190 vaccine recipients were recruited. Mean age was 52·4 ± 18·2 years. After the first dose, systemic reactions were reported by 57·5% of the participants, while injection site reactions were reported by 46·7%. The most common AEFIs were pain at the injection site, fatigue and headache. Grade 3 or 4 AEFIs were reported by 0·8% and 0·3% of the participants, respectively. After the second dose, systemic reactions were reported by 63·1% of the participants, while injection site reactions by 54·7%. The most common AEFIs were malaise, pain at injection site and myalgia. Grade 3 or 4 AEFIs were reported by 2·7% and 1·1% of the participants, respectively. Multivariate analysis showed younger age, being a woman and food allergies are risk factors for more severe AEFIs. Interpretation: Our results confirm a good tolerability profile for the population aged 18 and over providing useful data for vaccination campaigns ongoing in countries planning to use Gam-COVID-Vac. Funding: None
Racial differences in systemic sclerosis disease presentation: a European Scleroderma Trials and Research group study
Objectives. Racial factors play a significant role in SSc. We evaluated differences in SSc presentations between white patients (WP), Asian patients (AP) and black patients (BP) and analysed the effects of geographical locations.Methods. SSc characteristics of patients from the EUSTAR cohort were cross-sectionally compared across racial groups using survival and multiple logistic regression analyses.Results. The study included 9162 WP, 341 AP and 181 BP. AP developed the first non-RP feature faster than WP but slower than BP. AP were less frequently anti-centromere (ACA; odds ratio (OR) = 0.4, P < 0.001) and more frequently anti-topoisomerase-I autoantibodies (ATA) positive (OR = 1.2, P = 0.068), while BP were less likely to be ACA and ATA positive than were WP [OR(ACA) = 0.3, P < 0.001; OR(ATA) = 0.5, P = 0.020]. AP had less often (OR = 0.7, P = 0.06) and BP more often (OR = 2.7, P < 0.001) diffuse skin involvement than had WP.AP and BP were more likely to have pulmonary hypertension [OR(AP) = 2.6, P < 0.001; OR(BP) = 2.7, P = 0.03 vs WP] and a reduced forced vital capacity [OR(AP) = 2.5, P < 0.001; OR(BP) = 2.4, P < 0.004] than were WP. AP more often had an impaired diffusing capacity of the lung than had BP and WP [OR(AP vs BP) = 1.9, P = 0.038; OR(AP vs WP) = 2.4, P < 0.001]. After RP onset, AP and BP had a higher hazard to die than had WP [hazard ratio (HR) (AP) = 1.6, P = 0.011; HR(BP) = 2.1, P < 0.001].Conclusion. Compared with WP, and mostly independent of geographical location, AP have a faster and earlier disease onset with high prevalences of ATA, pulmonary hypertension and forced vital capacity impairment and higher mortality. BP had the fastest disease onset, a high prevalence of diffuse skin involvement and nominally the highest mortality
Proceedings of the Fifth Italian Conference on Computational Linguistics CLiC-it 2018
On behalf of the Program Committee, a very warm welcome to the Fifth Italian Conference on Computational Linguistics (CLiC-‐it 2018). This edition of the conference is held in Torino. The conference is locally organised by the University of Torino and hosted into its prestigious main lecture hall “Cavallerizza Reale”. The CLiC-‐it conference series is an initiative of the Italian Association for Computational Linguistics (AILC) which, after five years of activity, has clearly established itself as the premier national forum for research and development in the fields of Computational Linguistics and Natural Language Processing, where leading researchers and practitioners from academia and industry meet to share their research results, experiences, and challenges
Alteration behaviour of glass panes from the medieval Pavia Charterhouse (Italy)
The stained glass windows of the Pavia Carthusian Monastery are an important testimony of medieval glass making in which a wood-ash flushing component was used. Glass surfaces reveal alteration processes extending to depth, with evidence of microbial corrosion. Electron microprobe analyses coupled with EDS data allow the identification of different steps in the alteration process. Microbial attack occurs in an early stage and determines component leaching of the glass, with the development of reactions in which the crystallisation of gypsum is favoured. (c) 2006 Published by Elsevier Masson SAS
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