Identification of dyestuffs in historical textiles: strong and weak points of a non-invasive approach

The dyers of the past exploited a number of natural dyestuffs and dyeing procedures to obtain countless beautiful colours. It is hard to disclose which dyestuff has been used to dye a historical or an archaeological textile through non-invasive analytical techniques; therefore invasive analytical strategies, which require sampling, are generally employed to face this task. Some useful indication may nevertheless derive from the electronic transitions of dyes supported on the fibres and the signals can be easily recorded by reflectance spectroscopy in the visible range of the electromagnetic spectrum. The use of portable instruments equipped with fibre optics allows operation in-situ directly on the surface of the samples, through a non-invasive approach which is particularly suitable for the inspection of historical or archaeological samples. In this paper, the strong and weak points of visible fibre optics reflectance spectroscopy are discussed, in order to highlight its possible application as a first non-invasive step of a multi-technique analytical strategy devoted to the recognition of natural dyestuffs in ancient textile artefacts. Visible fibre optics reflectance spectra were collected from a large set of reference samples (wool and silk) coloured through various dyestuffs and dyeing procedures, in order to identify the signals of the coloured species that impregnate the fibres. The position of minimum, maximum and inflection points in the reflectance spectrawas evaluated and critically discussed, in order to identify the signals which are not contingent to dyeing procedures or to the fibre typology, and that can be therefore confidently used for analytical purposes. In particular, wavelength intervals were defined, in which the characteristic signals of the investigated dyestuffs (indigo, woad, Saxon blue, logwood, cochineal, madder, brazilwood, old fustic, weld, turmeric and saffron) are expected. It emerged that visible fibre optics reflectance spectroscopy is poorly selective for yellow dyes based on curcumins and flavonoids, while it generally succeeds in detecting the other dyestuffs considered herein. The information obtained from the reference sample set was then exploited to analyze an embroidered cloth dated from the seventeenth century. Preliminary information obtained via visible fibre optics reflectance spectroscopy was confirmed, or integrated, by the results obtained through liquid chromatography coupled with diode-array detection and mass spectrometry on extracts obtained from some coloured threads sampled from the historical cloth

Identificazione dei coloranti naturali con metodi non invasivi

Il lavoro presenta i risultati preliminari ottenuti da un\u2019indagine sistematica condotta con spettroscopia in riflettanza con fibre ottiche (FORS) nel campo spettrale visibile su un elevato numero di campioni di riferimento in lana e seta tinti con diverse materie prime coloranti naturali (anche in miscela) impiegando vari mordenti e diverse procedure di tintura. L\u2019analisi degli spettri FORS ottenuti ha consentito di valutare la presenza di caratteristiche spettrali discriminanti per alcune tra le diverse materie prime coloranti considerate (blu e rosse in particolare) e di valutarne le modificazioni associate ai differenti substrati e mordenti, oltre che evidenziarne gli effetti dovuti alla saturazione della tinta

Impact of a Dedicated Noninvasive Ventilation Team on Intubation and Mortality Rates in Severe COPD Exacerbations.

BACKGROUND: Compared with usual care, noninvasive ventilation (NIV) lowers the risk of intubation and death for subjects with respiratory failure secondary to COPD exacerbations, but whether administration of NIV by a specialized, dedicated team improves its efficiency remains uncertain. Our aim was to test whether a dedicated team of respiratory therapists applying all acute NIV treatments would reduce the risk of intubation or death for subjects with COPD admitted for respiratory failure. METHODS: We carried out a retrospective study comparing subjects with COPD admitted to the ICU before (2001-2003) and after (2010-2012) the creation of a dedicated NIV team in a regional acute care hospital. The primary outcome was the risk of intubation or death. The secondary outcomes were the individual components of the primary outcome and ICU/hospital stay. RESULTS: A total of 126 subjects were included: 53 in the first cohort and 73 in the second. There was no significant difference in the demographic characteristics and severity of respiratory failure. Fifteen subjects (28.3%) died or had to undergo tracheal intubation in the first cohort, and only 10 subjects (13.7%) in the second cohort (odds ratio 0.40, 95% CI 0.16-0.99, P = .04). In-hospital mortality (15.1% vs 4.1%, P = .03) and median stay (ICU: 3.1 vs 1.9 d, P = .04; hospital: 11.5 vs 9.6 d, P = .04) were significantly lower in the second cohort, and a trend for a lower intubation risk was observed (20.8% vs 11% P = .13). CONCLUSIONS: The delivery of NIV by a dedicated team was associated with a lower risk of death or intubation in subjects with respiratory failure secondary to COPD exacerbations. Therefore, the implementation of a team administering all NIV treatments on a 24-h basis should be considered in institutions admitting subjects with COPD exacerbations

l controllo di qualità per i trattamenti di pulitura: una proposta metodologica di cantiere

Lo stimolo per la predisposizione di un metodo di valutazione della qualità delle operazioni di pulitura, o di descialbo in questo caso, nasce in concomitanza con l’apertura del cantiere di restauro volto al recupero e alla valorizzazione delle pitture murali del donjon del castello di Quart. L’intento principale è stato quello di individuare un metodo che permettesse di monitorare e valutare oggettivamente la qualità della pulitura. Lo studio ha quindi riguardato l’identificazione di tecniche strumentali applicabili in situ e verificabili con il supporto di classiche tecniche di laboratorio atte a valutare l’andamento dei lavori e la qualità degli stessi. Le tecniche messe a punto hanno permesso di affrontare le situazioni di rischio per il tipo di pulitura selezionato e di predisporre un protocollo di misura atto a valutare la qualità e l’omogeneità degli interventi. Le strumentazioni impiegate per questo tipo di studio sono state il colorimetro, lo spettrofotometro FORS, la microscopia di cantiere e la microscopia di laboratorio. Il lavoro presenterà i risultati e le applicazioni di queste tecniche allo scopo del controllo dei metodi di pulitura

A combined use of FORS, XRF and Raman spectroscopy in the study of mural paintings in the Aosta Valley (Italy)

Mural paintings which decorate the external fa\ue7ade and the internal apsidal wall of a chapel dedicated to St. Maxime and located at Challand St. Victor in the Aosta Valley (Italy) have been analysed with a combined approach involving high-resolution fibre-optic reflectance spectroscopy (FORS), X-ray fluorescence (XRF) spectrometry and Raman spectroscopy. The paintings are attributed to Giacomino from Ivrea, a painter active around the midfifteenth century. In order to characterise the palette used by the painter and to yield information useful to restorers, the cited techniques were used either in situ with portable instruments and in laboratory, working on micro samples withdrawn from paintings. The global analytical approach, though not entirely non-invasive, can indeed be considered non-destructive as multiple analyses, including SEM-EDX, could be carried out on the micro samples, exploiting the features of each technique. On the basis of the information obtained, the palette was found to be composed of typical fresco pigments such as calcite, azurite, malachite, vermilion, red and yellow ochres. A particular situation was noted for black pigments since the presence of graphite, rather than wood or lamp carbon, was found, possibly related to the presence of graphite deposits in the Aosta Valley. Furthermore, the presence of smalt superimposed to azurite in areas showing evidence of repainting was detected, suggesting that paintings were subjected to retouching at a relatively early stage after the original execution. Finally, the presence of tin foils, used to decorate haloes of Evangelists, was ascertained

A role for atm in E-cadherin-mediated contact inhibition in epithelial cells

Ataxia telangiectasia is a hereditary pleiomorphic syndrome caused by loss of Atm, a phosphoprotein involved in multiple signaling pathways. Here, we propose a novel role for atm in cultured epithelial cells, namely the regulation of cell growth by contact inhibition. We show that atm is upregulated in epithelial cells reaching confluence. Conditional expression of the PI 3-Kinase domain of atm in non-confluent Tac-2 epithelial cells increases the expression of the anti-proliferative gene Tis-21 and downregulates key cell cycle regulator genes, such as cyclins A, B1, B2, E and E2. Finally, we demonstrate that upregulation of atm, and thus Tis-21, in confluent Tac-2 cells can be inhibited by an E-cadherin antibody blocking specifically homophilic E-cadherin interactions between adjacent cell surfaces. Altogether, these results suggest that atm could participate in a molecular pathway linking extracellular signalling to cell cycle control and may help further clarify the role of Atm in epithelial cell biology and carcinogenesis