In previous works a minimally invasive laser-assisted technique for vascular repair was presented. The technique rests on the photothermal adhesion of a biocompatible and bioresorbable patch containing Indocyanine Green that is brought into contact with the site to be repaired. Afterward the use of NIR millisecond-long light pulses generates a strong welding effect between the patch and the underlying tissue and in turn the repair of the wound. This technique was shown to be effective in animal model and provides several advantages over conventional suturing methods. Here we investigate and discuss the optical stability of the ICG-biopolymeric patches and the photothermal effects induced to the irradiated tissue.
In this work we focused on the laser removal of fungi growths and foxing stains from old paper artifacts. Irradiation tests
have been carried out using Nd:YAG laser’s second harmonic and characterized through morphological analysis by
means of optical microscopy and UV-VIS fluorescence, along with SEM-EDX microscopy. In addition, FTIR
spectroscopy and VIS diffuse reflectance spectroscopy have provided, respectively, very useful information on chemical
processes of the paper ageing and on the laser removal effectiveness. High selectivity and removal gradualness were
observed in the treatment of metal-induced foxing (Fe and Pb), likely arising from the contact with metal objects.
Moreover, similarly satisfactory results have been achieved for the removal of fungal colonies without inducing
detectable structural damage to the cellulose fibers. The best operating conditions determined have been finally used in
order to approach a practical conservation problem of an original engraving by G. B. Piranesi entitled Veduta del Ponte e
Castello Sant’Angelo (18th century).
In this work laser derusting and passivation process of iron objects of conservation interest were investigated. In
particular, the effects induced by laser irradiation of three lasers with different temporal emission regimes were studied,
exhibiting very different behavior. Nd:YAG(1064 nm) laser systems were employed in the experiments: a Q-Switching
laser with pulse duration of 8 ns, a Long Q-Switching laser with pulse duration of 120 ns and a Short Free Running pulse
duration in a range of 40–120 μs. These lasers are commonly used in conservation.
Lasers treatments were applied on iron samples subjected to natural weathering in outdoor conditions for about five
years. Moreover some experiments were also performed on metallic parts of an original chandelier from the seventies as
well as on a deeply corroded Roman sword. Results obtained reveals that longer pulse duration leads to phase changes on
the rust layer and a homogeneous black-grayish coating is formed on the surface (identified as magnetite) after treatment.
Whereas, QS laser pulses are capable to induce ablation of the corrosion layer exposing the pure metal underneath.
Finally, LQS interaction includes deep ablation with localized micro-melting of the metal surface and partial
transformation of the residual mineral areas was observed. The irradiation results were characterized through optical and
BS- ESEM along with Raman spectroscopy, which allowed a clear phenomenological differentiation among the three
operating regimes and provided information on their optimal exploitation in restoration of iron artifacts.
In the present work a non-invasive technological study on three molds from Magnani’s mills in Pescia (Pistoia, Italy)
was carried out. The three molds investigated have been those for making: 1) the invitation letters to the marriage
between Napoleon and Maria Luisa of Austria in 1810; 2) the paper sheets used by Pablo Picasso in 1917 for the
drawings of the Russian Ballets currently preserved in the Picasso Museum in Paris; 3) the holy manuscript Bhagavata
Purana realized in India in 1840 and currently preserved in the “Museum of Art” of San Diego. The chemical
composition of the metal alloy components were investigated and compared using Laser Induced Plasma Spectroscopy
(LIPS), electron microscopy (ESEM-EDX) and Ion Beam Analysis (IBA) while shape and size comparisons were carried
out by means of a homemade 3D digital microscopy device. Metallographic characterizations were also carried out on
some very small samples. This allowed pointing out the different crafting features of the three molds. The results
achieved and represent the first step towards an overall characterization, which will be carried out on Magnani’s mold
collections.
A systematic study on the use of Chlorophyll Fluorescence (CF) imaging in Pulsed Amplitude Modulated (PAM) for
assessing viability changes of biodeteriogen on stone artifacts has been carried out. The experimentation has been
performed on different phototrophic organisms of gravestone slabs from the monumental British Cemetery of Florence
(Italy). Since the viability of these organisms and then their chlorophyll fluorescence emission is strongly dependent on
the environmental conditions, a preliminary study on the effects of local patterns during the season was carried out. The
trend of the fluorescence quantum yield (QYmax) at different dark adapted times in different periods of the year was
determined. The results achieved in our work proves the effectiveness of the CF-PAM imaging for in situ lichen
characterizations in conservation studies and defines an optimized application protocol.
Here the exploitation of the laser induced plasma spectroscopy (LIPS) depth profiling in authentication studies of copper alloy and earthenware artifacts was investigated. Such an approach to the discrimination between original and counterfeit objects is based on the examination of the amplitude and shape of elemental distributions along ablation depths of several hundred microns. Thus, its application pass through preliminary assessments and correction of possible systematic errors of the measured profiles, which was the main aim of the present work. LIPS and ESEM-EDX measurements were carried out on two archaeological findings. We show that deep analytical probing produces not negligible intrinsic broadenings of the measured elemental Sn and Ca peaks and propose a correction based on the convolution integral. According to the latter, we demonstrate the actual depth profile can be calculated from the measured one through the experimental determination of the step response and the application of trial-and-error method.
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