Papers by Antonio Sansonetti
Gels
Copper complexes with different ligands (ethylenediaminetetraacetic acid, EDTA, ammonium citrate ... more Copper complexes with different ligands (ethylenediaminetetraacetic acid, EDTA, ammonium citrate tribasic, TAC, and alanine, ALA) were studied in aqueous solutions and hydrogels with the aim of setting the optimal conditions for copper stain removal from marble by agar gels, with damage minimization. The stoichiometry and stability of copper complexes were monitored by ultraviolet-visible (UV-Vis) spectroscopy and the symmetry of Cu(II) centers in the different gel formulations was studied by electron paramagnetic resonance (EPR) spectroscopy. Cleaning effectiveness in optimized conditions was verified on marble laboratory specimens through color variations and by determining copper on gels by inductively coupled plasma-mass spectrometry (ICP-MS). Two copper complexes with TAC were identified, one having the known stoichiometry 1:1, and the other 1:2, Cu(TAC)2, never observed before. The stability of all the complexes at different pH was observed to increase with pH. At pH 10.0, the...
In this research a portable non-destructive technique, the external reflection infrared spectrosc... more In this research a portable non-destructive technique, the external reflection infrared spectroscopy (portable-FTIR), is compared with the traditional analytical techniques, such as powder X Ray diffraction (XRD), optical and petrographic microscopy, scanning electron microscopy (SEM) and traditional bench transmission FTIR. Advantages and drawbacks of this technique are here discussed, taking into account that it was never applied systematically to mortars and cement materials
1 Department of Earth and Environmental Sciences, University of Milano-Bicocca. P.zza della Scien... more 1 Department of Earth and Environmental Sciences, University of Milano-Bicocca. P.zza della Scienza 1, Milano 20126, Italy 2 ICVBC – Institute for the Conservation and Valorisation of Cultural Heritage. National Research Council. Via Cozzi 53, 20125 Milano, Italy 3 Department of Industrial Chemistry “Toso Montanari”, University of Bologna. Viale del Risorgimento 4, Bologna, 40136, Italy
Materials evaluation, 2011
Several researches have been undertaken to understand the phenomenon of water transportation in a... more Several researches have been undertaken to understand the phenomenon of water transportation in any state required for determining the mechanism by which water accelerates damage to the monuments. An effective assessment of dampness requires knowledge of the thermo-hydrometric conditions determined by the exchange of water with the soil, air and other buildings. Moisture content may be measured with many different techniques, both direct and indirect that includes weighing tests, infrared thermography (IRT), microwave techniques and unilateral nuclear magnetic resonance (NMR). Weighing tests and IRT are accepted as standard techniques by conservators and the scientific community, and are used routinely on-site when moisture monitoring is seen as crucial for a conservation plan. Moisture Detection in the Historical Masonry (MOdihMA) research project involved several studies that compared testing procedures, which could be used on-site for the evaluation of masonry moisture content and water exchanges between building materials and the environment
Background: Although many studies have documented patient-, clinician-, and organizational barrie... more Background: Although many studies have documented patient-, clinician-, and organizational barriers/facilitators of primary care among people with mental illnesses, few have examined whether these factors predict actual rates of preventive service use. We assessed whether clinician behaviors, beliefs, characteristics, and clinician-reported organizational characteristics, predicted delivery of preventive services in this population. Methods: Primary care clinicians (n = 247) at Kaiser Permanente Northwest (KPNW) or community health centers and safety-net clinics (CHCs), in six states, completed clinician surveys in 2014. Using electronic health record data, we calculated preventive care-gap rates for patients with mental illnesses empaneled to survey respondents (n = 37,251). Using separate multi-level regression models for each setting, we tested whether survey responses predicted preventive service care-gap rates. Results: After controlling for patient-level characteristics, patients of clinicians who reported a greater likelihood of providing preventive care to psychiatrically asymptomatic patients experienced lower care-gap rates (KPNW γ= − .05, p = .041; CHCs γ= − .05, p = .033). In KPNW, patients of female clinicians had fewer care gaps than patients of male clinicians (γ= − .07, p = .011). In CHCs, patients of clinicians who had practiced longer had fewer care gaps (γ= − .004, p = .010), as did patients whose clinicians believed that organizational quality goals facilitate preventive service provision (γ= − .06, p = .006). Case manager availability in CHCs was associated with higher care-gap rates (γ=.06, p = .028). Conclusions: Clinicians who report they are likely to address preventive concerns when their mentally ill patients present without apparent psychiatric symptoms had patients with fewer care gaps. In CHCs, care quality goals may facilitate preventive care whereas case managers may not.
A 56 year old man complained of sudden bilateral shoulder pain following Brown Séquard syndrome w... more A 56 year old man complained of sudden bilateral shoulder pain following Brown Séquard syndrome without any remarkable trauma. Magnetic resonance imaging MRI showed that disc herniation intensely compressed the spinal cord, with a surrounding isointense halo of cerebrospinal fluid CSF on T1 and T2 weighted images at the C3 4 level. He presented to our emergency room with tetraparesis, and underwent anterior discectomy and fusion using a hydroxyapatite triphosphate complex spacer and an anterior cervical plate. A defect in the posterior longitudinal ligament PLL was seen, but adhesion between the dura and PLL was not observed. After removal of a fragment of the herniated disc, clear CSF leakage was seen. Dural laceration was sealed with absorbable hemostat and fibrin glue. The outcome was satisfactory, and complete recovery was noted at the 6 month follow up. There was no neurological change 5 years and 9 months after surgery. Intradural cervical disc herniation is relatively rare only 32 cases, including ours, have been reported. Definitive diagnosis of an intradural rupture of the herniated disc before surgery is difficult. Characteristic MRI findings may help to confirm diagnosis. The pathogenesis of intradural cervical disc herniation is not clear. We presume that bone fragments included in the herniated disc may play an important role in the pathogenesis, however further histopathological investigations are needed to substantiate the mechanism.
Journal of Cultural Heritage, 2021
The mechanism, the effectiveness, and the potential damage during limewash removal from wall pain... more The mechanism, the effectiveness, and the potential damage during limewash removal from wall painting models were evaluated for agar gels and water-based pads constituted by Arbocel TM BWW 40 cellulosic fibre. Cleaning materials in different formulations were compared: pure and with additives (ethylenediaminetetraacetic acid, EDTA, and ammonium citrate tribasic, TAC) in different percentages (2% and 3%). The cleaning action was evaluated on laboratory model samples, prepared with hematite a fresco and an egg-based tempera with limewash overlayers. Calcium and iron extracted by cleaning materials were quantified by inductively coupled plasma-mass spectrometry (ICP-MS). The potential damage to the hematite painting layers was also studied by electron paramagnetic resonance (EPR) spectroscopy. A visual observation of the limewash detachment induced by the overall cleaning was also performed. Results suggest that limewash removal mainly occurs by aqueous solution release from the cleaning system, with subsequent layer wetting, probable layer swelling, weakening and complete or partial detachment. A stronger limewash adhesion on the hydrophilic fresco surface than on tempera, was observed. None of the used cleaning materials resulted harmful to the integrity of the hematite layer underneath the limewash. A small damage in terms of extracted iron was detected in the cleaning systems after direct contact with fresco and tempera hematite layers; a "protective" effect by the tempera layer was observed for the pigment, due to the organic binder and triggered by the hydrophobic content of the egg-based medium. Cleaning materials with additives are more harmful than pure materials, with a greater coordinating ability for EDTA than for TAC, which increases with chelator percentage. Data suggest a more efficient backward transportation of aqueous solutions containing calcium and iron ions towards gels with respect to cellulose, due to their smallest pore size. All these results lead to operative suggestions: for fresco painting layers, pure gel allows both a good limewash removal and a lack of damage on the hematite layers. Instead, for tempera layers a good limewash removal and a negligible damage on the pigment was shown by gel, both pure and additivated with TAC, and pure cellulose. Therefore, the present study allows to identify proper characterization methods for evaluating effectiveness and damage in limewash removal and to give useful suggestions for the planning of repeated cleaning operations on a real polychrome object.
Journal of Cultural Heritage, 2021
The effectiveness of Agar gels for copper stain removal from marble surfaces was systematically s... more The effectiveness of Agar gels for copper stain removal from marble surfaces was systematically studied. Gels with different agar concentrations (1, 3, 5 %) and additives (ethylenediaminetetraacetic acid, EDTA, and ammonium citrate tribasic, TAC), applied for different contact times (30 and 60 min) on laboratory marble specimens, were tested. For better characterization, hydrogels were lyophilised and xerogels were obtained. Systematic comparison of different formulations was feasible on xerogels and performed in terms of: i) the morphological properties, by field-emission scanning electron microscopy (FE-SEM); ii) the type of Cu(II)-complexes formed and their quantitative comparison by electron paramagnetic resonance (EPR) spectroscopy; iii) the total amount of copper removed from marble surfaces, by Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). Agar 1% with TAC exhibited the highest effectiveness for copper stain removal after 60 min contact (431 µg/cm 2 of copper mass removed per agar surface area). Such a good cleaning performance can be ascribed to the co-presence of three favourable properties: i) optimal gel concentration; ii) presence and iii) type of additive. In fact, it was observed that both the low gel concentration and the presence of TAC are 2 related to a narrow pore size distribution, besides the possibility of copper coordination. The presence of EDTA results in the collapse of the pores and in worse cleaning performances of gels, with respect to gels with TAC. Thus, a new method for studying gels was suggested, which allowed to suggest the best conditions for copper salt removal from built heritage.
European Polymer Journal, 2020
Agar is a natural polymer commonly used in various fields of application ranging from cosmetics t... more Agar is a natural polymer commonly used in various fields of application ranging from cosmetics to the food industry. In particular, for over forty years agar gels have been used in the field of conservation of Cultural Heritage where they are considered as one of the main well-performing tools in cleaning procedures. In the present work, the relation between the chemical composition and the mechanical strength of four different agar hydrogels was evaluated by comparing the results obtained via pyrolysis-gas chromatography/mass spectrometry and rheological characterization. Agar composition was studied by means of a pyrolysis-gas chromatography/mass spectrometry approach in order to differentiate the anhydrous, galactose and glucose units. Pristine agar gels, gels after double annealing, and gels with and without chelating agent were studied by means of amplitude, frequency and time sweep rheological tests to evaluate all the preparation approaches commonly used by conservators, also taking into account changes in the transparency via UV-vis spectroscopy. A high percentage of anhydrous units in the polymer backbone was found to provide superior mechanical stiffness to the pristine hydrogels, even if it did not seem to affect their long-term stability. The annealing process significantly improved the rheological response of galactose-rich agar hydrogels being able to promote the establishment of additional crosslinking points, whereas the additive presence showed to improve the hydrogel stiffness owing to a more structured polymer network. Moreover, the progressive reduction of the impurities and/or network defects within the hydrogels occurring due to the annealing process slightly increased the transparency of the hydrogels, which is an important aspect for applications in the conservation of Cultural Heritage.
Proceedings of the 6th International Conference on Emerging Technologies in Non-Destructive Testing (Brussels, Belgium, 27-29 May 2015), 2015
The decay of Leonardo mural paintings requires the highest integration of investigations. Authors... more The decay of Leonardo mural paintings requires the highest integration of investigations. Authors identified the soluble salts together with their transport phenomena. The analysis correlated the salts distribution and the thermalhygrometric variations along 4 years. Innovative use of statistical analysis of the changes of salts phases for evaluating of risk factors. Considering salts soluble and their transport phenomena prevents the use of water for restoration.
Research for Development, 2014
Annali Di Chimica, 2006
The facade of the church of the Pavia Charterhouse, built at the end of the 15th century, shows o... more The facade of the church of the Pavia Charterhouse, built at the end of the 15th century, shows outstanding decorative features made of different stone materials, such as marbles, breccias and sandstones. Magnificent ornamental elements are made of thin lead sheets, and some marble slabs are inlaid with them. Metal elements are shaped in complex geometric and phytomorphic design, to form a Greek fret in black contrasting with the white Carrara marble. Lead pins were fixed to the back of the thin lead sheets with the aim of attaching the metal elements to the marble; in so doing the pins and the lead sheets constitute a single piece of metal. In some areas, lead elements have been lost, and they have been substituted with a black plaster, matching the colour of the metal. To the authors' knowledge, this kind of decorative technique is rare, and confirms the refinement of Renaissance Lombard architecture. This work reports on the results of an extensive survey of the white, orange...
Examples of painted layers on statues, bas-reliefs and other architectural elements have been dis... more Examples of painted layers on statues, bas-reliefs and other architectural elements have been discovered in the course of conservation works in last decades. In most of the cases painting layers are in the state of remnants because of decay mechanisms, soiling, and invasive cleaning. Nevertheless, these colour relics witness ancient pictorial techniques, and contribute to define a symbology, an iconography, and the importance of stone elements in a complex building. An important high relief representing the figure of St. Siro, who is traditionally said to have been the first bishop of Pavia during the 1 st century, but probably lived during 4 th century, is conserved in Sts. Gervasius and Protasius Church in Pavia. The high-relief, a limestone slab of about 116 x 49 cm, was covered by a lime wash light-brownish in colour, probably imitating other stone elements in the Church façade, at the center of which the sculpted slab was embedded in the masonry till 1861. After then the slab w...
The European Physical Journal Plus
Abstract.Mortars are important building materials that are produced using different raw materials... more Abstract.Mortars are important building materials that are produced using different raw materials for the binder and for the aggregate; the latter is usually composed of several different mineral phases, or ceramic (cocciopesto) or rocks fragments. Traditional local recipes often include a vast range of organic and inorganic additives, but unfortunately no precise descriptions of the recipes have been reported in historical sources. Knowledge of their composition could be extremely significant in terms of information on past technology and improvements in today’s conservation work. In recent years, non-invasive portable instruments have been increasingly used in conservation science, particularly for the analysis of paintings, but little research focuses on historical building materials. In this study, the performance of non-invasive external reflection infrared spectroscopy (ER-FTIR) is tested on model samples, which are prepared according to past recipes collected from historical manuals, and using conservation best practices. The results are discussed and compared with traditional analytical techniques, such as bench top transmission and attenuated total reflectance (ATR) infrared spectroscopy, combined with powder X-ray diffraction (XRD). The influence of surface roughness on reflection infrared spectroscopy signals is also considered and investigated.
Applied Spectroscopy
Organic compounds have frequently been added into lime mortars for property modifications, in ord... more Organic compounds have frequently been added into lime mortars for property modifications, in order to satisfy various functional needs in building techniques. This study applies Fourier transform infrared (FT-IR) spectroscopy in transmission, reflection, and attenuated total reflection (ATR) modes to characterize lime-based mortar specimens containing oxblood, which has been used as additive as a common practice of long history in many parts of the world. The specimens were prepared basing upon a 19th-century Italian historic recipe, with the intention to have a better understanding on the possible characteristics of such mortars. Thermal analysis, color measurement, and static contact angle test were also used. After curing, the specimens show a distinctive dark-red color on the top surface, which is different from the bulk. Color measurements on the surface suggest that this color was formed at an early stage and was able to maintain stable for a relatively long period of time. B...
Microchemical Journal, 2016
Abstract The effectiveness and the mechanism of copper stain removal from stones by agar gels was... more Abstract The effectiveness and the mechanism of copper stain removal from stones by agar gels was systematically studied using marble laboratory specimens, stained and cleaned in well-controlled and reproducible conditions. The same cleaning procedure was also applied on the marble base of Napoleon's statue by A. Canova. The water release from agar gels to stones was investigated by capillarity absorption and unilateral Nuclear Magnetic Resonance. The cleaning by different agar gel formulations (pure and added with chemicals) was studied both on the stone substrate (optical microscopy and colour measurements) and in the gels (inductively coupled plasma-atomic emission spectrometry, electron paramagnetic resonance spectroscopy). Among the considered cleaning systems, the most effective ones for copper removal were agar gels 3% containing additives, with no significant difference among the used additives. However, agar gels with additives host copper in different ways: in gels added with ethylenediamine tetraacetic acid (EDTA), all copper centers are coordinated, while copper centers are also dispersed in water within gels added with ammonium citrate tribasic (TAC). The stain cleaning process of stones probably starts with the diffusion of water at the gel-stone interface, but it finds the driving force in the copper coordination.
Microchemical Journal, 2015
Abstract A multi-analytical approach was adopted to compare different cleaning methods during the... more Abstract A multi-analytical approach was adopted to compare different cleaning methods during the conservation works on two bronze artefacts: the Brera's Napoleon by A. Canova and the Florence Baptistery's North Door by L. Ghiberti. An appropriate number of surface areas were identified, and their properties and homogeneity were characterised in situ by means of colorimetry, Eddy Current patina thickness measurements, FTIR spectroscopy and electrochemical impedance spectroscopy (EIS). On the Napoleon statue, three sets of laser cleaning parameters were adopted on distinct selected areas. On the North Door, a mechanical and two chemical cleaning methods were applied on two separate areas; both chemical methods were based on Agar gel. The results on surface composition, appearance and corrosion rate of the different cleaning methods were compared with the properties of the uncleaned area with the same set of in situ analytical techniques. Measurements results were statistically analysed to take into account the lack of homogeneity typical of outdoor bronze surfaces. Based on the results obtained on the two bronze artefacts analysed, the role of the analytical techniques adopted is discussed. The effectiveness of the described in situ multi-analytical approach towards a better conservation–restoration methodology for outdoor bronzes is enlightened.
Studies in Conservation, 2015
We report on tests to remove naturally and artificially aged shellac varnish by laser and traditi... more We report on tests to remove naturally and artificially aged shellac varnish by laser and traditional chemical cleaning from the substrates of mural paintings. Optical tools were used for the evaluation of cleaning processes, in particular laser microprofilometry to assess the changes in the surface morphology and time-domain confocal optical coherence tomography (OCT) to evaluate varnish thickness. The cleaning assessment was integrated with molecular characterization provided by portable Fourier transform infrared spectroscopy operating in reflectance mode, and colorimetric measurements. This complete analytical approach led to optimized laser-based cleaning tests at 1.9 and 2.6 J/cm 2 in the presence of isopropanol, which ensured controllable and safe partial removal of shellac varnish without alteration to the substrate morphology.
Journal of Cultural Heritage, 2000
For the peculiar artworks such as stucco plasterworks cleaning is troublesome for different reaso... more For the peculiar artworks such as stucco plasterworks cleaning is troublesome for different reasons: weak mechanical behavior, high porosity and resulting water absorption, partial water solubility in the case of gypsum plaster. The choice of the cleaning method, especially as concerns gypsum based stucco materials, is crucial in assuring the lowest harmfulness possible together with a good level of efficacy. With the term agar we name a powder product composed mainly of polysaccharides and extracted from red algae species. When boiled with water, in a percentage range in between 0.5 and 5, it produces a colloidal solution that gellifies towards 35 °C. It can be used gelified and cold placed on a plan stucco surface, tepid and fluid poured on a surface relief or otherwise milled till a snow consistency, then pressed as a pad onto any surface; it has a high content of water which is slowly released into the porous substrate system. Hence the water-soluble components of soiling presen...
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Papers by Antonio Sansonetti