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A lead-EDTA spectrophotometric methods for sulphate determination
No full textA method for the detn. of sulfate in aq. solns. is based on the pptn. of Pb sulfate, which is then dissolved by an EDTA soln., and spectrophotometric detn. (l = 242 nm) of the Pb-EDTA complex. A H2O-MeOH mixt. is used as the solvent in order to decrease the soly. of the Pb sulfate, and Ba(II) is added to the soln. contg. excess EDTA in order to eliminate the EDTA interference. Sulfate concns. >5 mg/L can be detd. without preconcn. with a relative std. deviation <0.035; the scatter of absorbance measurements around the calibration line corresponds, on the av., to 0.4 mg/L, when 15 mL of sample are taken for anal
Technology, colours, forms, and shapes in the 2nd century glass opus sectile materials from the villa of Lucius Verus in Rome
No full textAttribuzione di migliaia di lastre in vetro, monocromo e policromo, confluite nella collezione Gorga, alla villa dell'imperatore Lucio Vero (II secolo) sulla via Cassia, e studio delle tecniche di produzione
La microscopia elettronica a scansione (SEM) con spettrometria a dispersione di energia (EDS) come tecnica di supporto nella diagnosi e nel restauro dei dipinti murali
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Chlamydia pneumoniae respiratory infections among patients infected with the human immunodeficiency virus
No full textToF-SIMS study of gilding technique in the fresco Vela della Castità by Giotto's school
No full textTime of flight secondary ion mass spectrometry (ToF-SIMS) has become a fundamental analytical technique in cultural heritage studies to obtain the identification and distribution of organic components present in artworks. A sample taken from the soldier's golden shield decoration in the fresco Vela della Castità (San Francesco Lower Basilica, Assisi) was studied. The metal leaves for gilding decoration on wall paintings are usually applied using an oil-resin mordant as adhesive. In this work, organic and inorganic compounds used in this peculiar painting technique were identified by ToF-SIMS technique. High mass resolution spectrometry was applied for the chemical characterization of organic materials present in oil-resin binding media and red lake paint layer. Presence of azelaic, palmitic and stearic acids proved the nature of the oil binder between plaster and tin leaf and between tin and gold leaf. The analyses revealed also the presence of colophony, a natural resin used as an adhesive in this painting technique. Furthermore, the fresco cross section was studied using ToF-SIMS imaging. ToF-SIMS results agree with and are complementary to those obtained by other analytical techniques: scanning electron microscopy with X-ray microanalysis and Fourier transform infrared spectroscopy
Chlamidia pneumoniae respiratory infections among patients infected with the human immunodeficiency virus
No full textMarked activation of the tumour necrosis factor system in AIDS-associated cryptococcosis
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