Anesthesia awareness and the bispectral index Avidan, Michael S; Zhang, Lini; Burnside, Beth A ...
New England journal of medicine/The New England journal of medicine,
03/2008, Letnik:
358, Številka:
11
Journal Article
Recenzirano
Odprti dostop
Awareness during anesthesia is a serious complication with potential long-term psychological consequences. Use of the bispectral index (BIS), developed from a processed electroencephalogram, has been ...reported to decrease the incidence of anesthesia awareness when the BIS value is maintained below 60. In this trial, we sought to determine whether a BIS-based protocol is better than a protocol based on a measurement of end-tidal anesthetic gas (ETAG) for decreasing anesthesia awareness in patients at high risk for this complication.
We randomly assigned 2000 patients to BIS-guided anesthesia (target BIS range, 40 to 60) or ETAG-guided anesthesia (target ETAG range, 0.7 to 1.3 minimum alveolar concentration MAC). Postoperatively, patients were assessed for anesthesia awareness at three intervals (0 to 24 hours, 24 to 72 hours, and 30 days after extubation).
We assessed 967 and 974 patients from the BIS and ETAG groups, respectively. Two cases of definite anesthesia awareness occurred in each group (absolute difference, 0%; 95% confidence interval CI, -0.56 to 0.57%). The BIS value was greater than 60 in one case of definite anesthesia awareness, and the ETAG concentrations were less than 0.7 MAC in three cases. For all patients, the mean (+/-SD) time-averaged ETAG concentration was 0.81+/-0.25 MAC in the BIS group and 0.82+/-0.23 MAC in the ETAG group (P=0.10; 95% CI for the difference between the BIS and ETAG groups, -0.04 to 0.01 MAC).
We did not reproduce the results of previous studies that reported a lower incidence of anesthesia awareness with BIS monitoring, and the use of the BIS protocol was not associated with reduced administration of volatile anesthetic gases. Anesthesia awareness occurred even when BIS values and ETAG concentrations were within the target ranges. Our findings do not support routine BIS monitoring as part of standard practice. (ClinicalTrials.gov number, NCT00281489 ClinicalTrials.gov.).
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 Reviewed
Technology of production of polychrome lustre Molina, Gloria; Tite, Michael S.; Molera, Judit ...
Journal of the European Ceramic Society,
09/2014, Letnik:
34, Številka:
10
Journal Article, Publication
Recenzirano
Odprti dostop
Lustre is a decoration consisting of a few hundreds of nanometres thick surface layer of silver and copper metal nanoparticles incorporated into the glaze. Polychrome lustreware with several ...combinations of colours and shines was produced in Abbasid Iraq in the 9th century AD. Three colour combinations, black plus red, white-silvery plus red-coppery and yellow-golden plus red-coppery, have been studied, and the materials and methods of production determined. Two separated firings the first for the copper and the second for the silver lustre were performed. The black, white, yellow and green colours of the silver lustres are associated with the different sizes of the nanoparticles and to their distribution in the layer. Although the addition of lead and tin in the initial mixture is demonstrated, their incorporation in the glaze has been found to be the key factor in the production of the red-coppery and yellow-golden lustre.
Egyptian blue, which was the first synthetic pigment to be used in antiquity, consists of crystals of calcium‐copper tetrasilicate (i.e. cuprorivaite (CaCuSi4O10)). The physical processes associated ...with the formation of Egyptian blue were investigated by high‐temperature X‐ray diffraction measurements on synthetic mixtures of quartz, malachite, and calcium carbonate. The high‐brilliance, high‐energy radiation ID15B beamline at the European Synchrotron Radiation Facility was necessary to ensure good time/temperature resolution, penetration, and high‐quality data. The results established that the Egyptian blue crystals are formed through nucleation and growth within a liquid or glass phase, even for mixtures with an alkali content as low as 0.3 wt% soda. Furthermore, the microstructures observed in a scanning electron microscope indicated the ancient Egyptian blue pigments were produced from mixtures containing several weight percent of alkali.
The generally accepted theory is that the demand for Islamic glazed pottery started in Abbasid Iraq in the 9th century AD with the production of a range of glazed wares in response to the import of ...Chinese stonewares and porcelains. However, Oliver Watson has recently proposed that the demand for Islamic glazed pottery first occurred in Egypt and Syria in the 8th century AD resulting in the production of opaque yellow decorated wares. Using a combination of SEM analysis of polished cross-sections, and surface analysis using hand-held XRF or PIXE, Coptic Glazed Ware from Egypt, Yellow Glazed Ware from Syria, and comparable wares from Samarra, Kish and Susa have been analysed. The analyses show that the opaque yellow decoration was the result of lead stannate particles in a high lead glaze, which it is suggested was produced using a lead-silica-tin mixture. The use of lead stannate in the production of yellow opaque glazes is explained in terms of technological transfer from contemporary Islamic glassmakers who continued the Byzantine tradition of glassmaking. It is further argued that the introduction of opaque yellow glazed pottery into Mesopotamia could have provided the social context for the sudden emergence of tin-opacified white glazed pottery in Abbasid Iraq in the 9th century AD. However, in view of the very different glaze compositions employed for the yellow and white opaque glazes, it seems probable that the white tin-opacified glazes used for Abbasid cobalt blue and lustre decorated wares represent a separate but parallel technological tradition with its origins in the production of Islamic opaque white glass.
•Lead stannate used to produce yellow opaque glazes in Egypt and Syria in 8th century AD.•Use of lead stannate reflects awareness of Byzantine glassmaking technology.•Yellow glazed ware provided social context for emergence of Abbasid white glazed ware.•Yellow and white glazed wares could represent separate but parallel technological traditions.•In Egypt, there was a switch back to lead antimonate for yellow opaque glazes.
Color and Golden Shine of Silver Islamic Luster Gutierrez, P. Carolina; Pradell, Trinitat; Molera, Judit ...
Journal of the American Ceramic Society,
August 2010, Letnik:
93, Številka:
8
Journal Article
Recenzirano
Golden‐like luster decorations on glazed ceramics from early Islamic times (9–12th centuries AD) consist of a nanocomposite submicrometric layer made of silver metal nanoparticles. The color and ...golden‐like reflectivity of these decorations are dominated by the nonlinear optical response and Mie scattering of the silver nanoparticles. We demonstrate that the enhanced golden‐like reflectivity occurs only for dense nanoparticulated layers and that they were obtained by adding PbO to the alkaline glaze. This resulted in reduced diffusivity of silver in the glaze leading to more concentrated and thinner luster layers that formed closer to the glaze surface. The result obtained adds new insights into the high technological level attained during Islamic times and also has important historical implications, giving both new clues concerning the lead enrichment of the glazes during this period, and some basis for the medieval Alchemy search for the production of “gold” from other metals.
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.
A small group of opaque yellow glazed sherds has recently been identified among the ceramics excavated at the Islamic city of Madīnat al-Zahrā’ 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 Madīnat al-Zahrā’, 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 Madīnat al-Zahrā’ 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.
Previous research has shown that Iznik glazes are characterized by low potash and magnesia contents. It was therefore suggested that the flux used was either a purified plant ash or some unidentified ...mineral source of soda. More recently, as a result of the detection of small, but significant, amounts of boron and lithium in Byzantine glasses from western Turkey, which also exhibit low potash and magnesia contents, it has been suggested that the source of the flux used was a soda‐rich evaporite associated in some way with the extensive borax deposits in the region. LA–ICP–MS has been used to establish that Iznik glazes also contain similarly small amounts of boron and lithium. The Na/K, Na/Mg, Na/Ca and Na/B ratios for these Iznik glazes are shown to be comparable to the equivalent ratios calculated from published data for waters from a range of Na–HCO3 type hot springs in western Turkey, with the closest match being to the hot springs around Afyon‐Gazligöl, which is consistent with documentary evidence. It is therefore proposed that the soda‐rich salts produced by evaporating water from these springs to dryness would have provided the flux required for the production of Iznik glazes and high‐boron Byzantine glasses.
•Continuity and innovation in the 10th CE Tunisian polychrome glazed wares.•Polychrome white opaque Fatimid-Zirid glazes have quartz as opacifier.•Tin glaze technology did not reach Tunisia before ...the Fatimid occupation of Egypt.•The role of the Fatimid in the spread of tin glazes in the Mediterranean.•The connection between Tunisia and Islamic Spain and Sicily.
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.
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