Tracing the tin-opacified yellow glazed ceramics in the western Islamic world: the findings at Madinat al-Zahra’

A small group of opaque yellow glazed sherds has recently been identified among the ceramics excavated at the Islamic city of Madinat al-Zahra’ near Cordoba, in al-Andalus (southern Spain), which was founded in 936 AD as the seat of the Umayyad Caliphate power. A small group of sherds from Madinat al-Zahra’, which can be dated to about 960–980 AD, has been examined in polished section in a SEM with EDS attached. These analyses have established that the Madinat al-Zahra’ sherds were opacified with lead stannate, and not lead antimonate, as was being used to opacify yellow glazed ceramics in Egypt and Tunisia in the ninth and tenth centuries AD. Islamic opaque yellow glazed ceramics, with lead stannate as the opacifier, were first produced (Beiträge Zur Islamischen Kunst Und Archäologie 4:125–144, 2014) in Egypt and Syria in seventh/eighth centuries AD, and from there, the technology spread eastwards into Iraq and Iran in the ninth century AD and continued in use in Iran and Central Asia into the tenth century AD and beyond. However, the question of where these opaque yellow glazed ceramics were produced has not been fully resolved. Because such ceramics are extremely rare in al-Andalus, it seems most likely that they were either imported from Iran or Central Asia or produced locally by potters arriving from these areas. The study adds one further, yet not fully understood chapter to the story of a persistent glaze technology which has been widely ignored.Peer ReviewedPostprint (published version

The colour and golden shine of early silver Islamic lustre

A selection of lustres including 9th century AD polychrome and 10th century AD monochrome Abbasid lustres from Iraq, and 10th to 12th centuries AD Fatimid lustres from Egypt and Syria is studied in the present paper. The selection is based on previous studies that demonstrated that all of them contain metal silver nanoparticles and copper, which, when present, appears either as Cuþ or Cu2þ dissolved in the glaze. They show different colours, green, yellow, amber, and brown, and may also show or lack a golden-like reflectivity, which results mainly from average size and concentration in the layer of the silver nanoparticles. In this paper, a depth profile composition of the lustre layers is determined using Rutheford Backscattering Spectroscopy, allowing the determination of the total silver content, concentration of silver, copper to silver ratio, and thickness of the lustre layers. We show that the enhanced golden-like reflectivity occurs only for layers with a high concentration of silver, and that the addition of PbO to the alkaline glaze helps the formation of more concentrated layers. The results obtained provide new hints concerning the lead enrichment of the glazes during this period.Peer ReviewedPostprint (published version

Technology of production of Syrian lustre (11th to 13th century)

Lustre is a decoration consisting of a surface layer of silver and copper metal nanoparticles, a few hundreds of nanometres thick and incorporated into the glaze. It shows a colourful metallic and iridescent appearance which makes use of the quantum confined optical response of the metallic nanoparticles. Three apparently unrelated lustre decorations, yellow-orange golden (Tell Minis), a dark brown-reddish with iridescences (Raqqa) and yellow-brown golden (Damascus) were produced in the same area in successive periods over tin and lead-free glazes which is known to require specific strategies to obtain a metallic shiny lustre. The composition and nanostructure of the lustre layers are analysed and the materials and specific firing conditions followed in their production determined. The optical properties of the lustre layers have been analysed in terms of the nanostructure obtained and correlated to the specific processing conditions.Peer ReviewedPostprint (author's final draft

Therapeutic DNA vaccine induces broad T cell responses in the gut and sustained protection from viral rebound and AIDS in SIV-infected rhesus macaques.

Immunotherapies that induce durable immune control of chronic HIV infection may eliminate the need for life-long dependence on drugs. We investigated a DNA vaccine formulated with a novel genetic adjuvant that stimulates immune responses in the blood and gut for the ability to improve therapy in rhesus macaques chronically infected with SIV. Using the SIV-macaque model for AIDS, we show that epidermal co-delivery of plasmids expressing SIV Gag, RT, Nef and Env, and the mucosal adjuvant, heat-labile E. coli enterotoxin (LT), during antiretroviral therapy (ART) induced a substantial 2-4-log fold reduction in mean virus burden in both the gut and blood when compared to unvaccinated controls and provided durable protection from viral rebound and disease progression after the drug was discontinued. This effect was associated with significant increases in IFN-γ T cell responses in both the blood and gut and SIV-specific CD8+ T cells with dual TNF-α and cytolytic effector functions in the blood. Importantly, a broader specificity in the T cell response seen in the gut, but not the blood, significantly correlated with a reduction in virus production in mucosal tissues and a lower virus burden in plasma. We conclude that immunizing with vaccines that induce immune responses in mucosal gut tissue could reduce residual viral reservoirs during drug therapy and improve long-term treatment of HIV infection in humans

Archaeometry in Britain

Tite Michael S. Archaeometry in Britain. In: Histoire & Mesure, 1994 volume 9 - n°3-4. Archéologie II. pp. 403-404

Technological characterisation of egyptian blue

The principal aim has been to obtain information on the procedures used in antiquity to produce the different fabrics, ranging from soft and friable to hard and semi-vitrified, which are composed of Egyptian Blue. Four pieces of Egyptian Blue from Egypt and Mesopotamia have been examined using the scanning electron microscope and have been compared with Egyptian Blue produced in the laboratory. The results show that Egyptian Blue can be satisfactorily synthesized by firing an appropriate mixture to 900-1000°C for a few hours and to produce pieces comparable in hardness and microstructure with the ancient samples, a single firing in this temperature range is sufficient for the softer fabrics. However, to produce the harder fabrics it is necessary to fire for a second time after grinding and remoulding the material from the first firing.L'objectif principal a été d'obtenir des informations sur les procédés employés dans l'antiquité pour produire les différentes pâtes, allant du tendre et friable au dur et semi-vitrifié, qui sont composées de Bleu Egyptien. Quatre objets de Bleu Egyptien d'Egypte et de Mésopotamie ont été examinés au microscope électronique à balayage et ont été comparés avec du Bleu Egyptien produit au laboratoire. Les résultats montrent que le Bleu Egyptien peut être synthétisé de manière satisfaisante en chauffant un mélange approprié à 900-1000°C pour quelques heures et qu'on peut produire des pièces comparables en dureté et en microstructure avec les échantillons antiques, une seule chauffe dans cette gamme de température est suffisante pour les pâtes tendres. Cependant, pour produire les pâtes les plus dures il est nécessaire de chauffer une deuxième fois après avoir broyé et remodelé le produit du premier chauffage.Tite Michael S., Bimson Mavis, Meeks Nigel D. Technological characterisation of egyptian blue. In: Revue d'Archéométrie, n°1, 1981. Actes du XXe symposium international d'archéométrie Paris 26-29 mars 1980 Volume III. pp. 297-301

Analysis of Syrian lustre pottery (12th-14th centuries AD)

Lustre is a product of skilled artisans and its production was spread to different regions by the migration of artisans. Each lustre production has its own peculiarities not only in the composition and microstructure of the lustre but also in the paste and glaze compositions, processing and firing conditions. Syrian lustre is particularly interesting as it shows technological innovations with respect to the earlier Abbasid and Fatimid lustre productions with the use of transparent tin-free glazes (often alkaline) and stonepastes. In particular, the use of alkaline glazes required the introduction of technological novelties in order to increase the chances to produce a metallic-like shining lustre. We present first studies made on the lustre layer of early Syrian productions, namely Tell Minis (first half 12th century AD), Raqqa and related wares (second half of the 12th century AD and first third of the 13th century AD) and Damascus (second half of the 13th century AD and 14th century AD)

From tin- to antimony-based yellow opacifiers in the early Islamic Egyptian glazes: Regional influences and ruling dynasties

A small group of opaque yellow glazed sherds has recently been identified among the ceramics excavated at the Islamic city of Madinat al-Zahra’ near Cordoba, in al-Andalus (southern Spain), which was founded in 936 AD as the seat of the Umayyad Caliphate power. A small group of sherds from Madinat al-Zahra’, which can be dated to about 960–980 AD, has been examined in polished section in a SEM with EDS attached. These analyses have established that the Madinat alZahra’ sherds were opacified with lead stannate, and not lead antimonate, as was being used to opacify yellow glazed ceramics in Egypt and Tunisia in the ninth and tenth centuries AD. Islamic opaque yellow glazed ceramics, with lead stannate as the opacifier, were first produced (Beiträge Zur Islamischen Kunst Und Archäologie 4:125–144, 2014) in Egypt and Syria in seventh/eighth centuries AD, and from there, the technology spread eastwards into Iraq and Iran in the ninth century AD and continued in use in Iran and Central Asia into the tenth century AD and beyond. However, the question of where these opaque yellow glazed ceramics were produced has not been fully resolved. Because such ceramics are extremely rare in al-Andalus, it seems most likely that they were either imported from Iran or Central Asia or produced locally by potters arriving from these areas. The study adds one further, yet not fully understood chapter to the story of a persistent glaze technology which has been widely ignored.Peer Reviewe

Polychrome glazed ware production in Tunisia during the Fatimid-Zirid period: New data on the question of the introduction of tin glazes in western Islamic lands

The production of polychrome decorated ceramics began in Ifriqiya in the 9th century under Aghlabid rule, with continuity during the 10th century under the Fatimids. These comprised finely painted brown and green designs with a characteristic yellow background (a transparent lead glaze containing iron oxide). This production was substituted in the 11th century by a polychrome production over a white tin opaque glaze. The hypothesis stating that tin glazes were introduced in Tunisia after the Fatimids took over Egypt has been recently proposed. However, polychrome ceramics with a white opaque background have been found in 10th century archaeological sites which might indicate otherwise. A ceramic assemblage found at the site of Bir Ftouha dating from the Fatimid-Zirid period which contains polychrome with both transparent yellow and white opaque backgrounds has been analysed. The white opaque glazes do not contain tin but were opacified by the addition of large quartz particles. This study supports the theory that tin glazes reached Tunisia after the Fatimid occupation of Egypt and is the first step to answering many open questions regarding the spread of tin glaze in the Mediterranean, the role of the Fatimids and the connections of Ifriqiya with Islamic Spain and Sicily.Postprint (author's final draft