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The dispute over the paternity of western paper is a longstanding problem. In Italy, a country that has a long tradition of papermaking, many cities compete for the leadership in the production of this material; on the other hand, several studies attribute to Fabriano (13th century), a little center in Marche region, the birth of modern paper and its diffusion throughout Europe. During the 14thcentury, the nearby town of Camerino imposed itself on the paper market, triggering a historic rivalry with the manufacture of Fabriano. As scientific studies on these different productions are missing, a comparative, multidisciplinary investigation has been carried out to characterize a set of thirteenth-fifteenth century handmade papers from Camerino-Fabriano area. Several analytical techniques–some non-invasive such as Fourier-transform infrared spectroscopy (FTIR) and portable magnetic resonance (unilateral NMR), joined to micro-destructive ones such as scanning electron microscopy (SEM), 13C CPMAS NMR spectroscopy, thermo-gravimetric analysis (TGA), sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and reverse-phase liquid chromatography (RP-HPLC)–have been employed in order to study the morphology of the paper documents, to identify the substances used in production process and to define their preservation state. Moreover principal component analysis (PCA) has been applied to the spectroscopic data, allowing the clustering of Fabriano documents with respect to Camerino ones and dividing the samples in two sets. This work improves and confirms knowledges on paper production in Marche region, and the experimental data collected highlight similarities and differences between Camerino and Fabriano manufactures.

International audience; The extraction of cellulose nanocrystals (NCC) from cotton textile waste, constituted by 70% long fibers and 30% cotton linter, was performed through the action of sulfuric acid followed by solution neutralization with two different alkalis, namely ammonia and sodium bicarbonate, which yielded microcellulose (MCC), then centrifuged to NCC. The action of the two alkalis was compared as for fiber repeatability and morphology, and the results obtained using ammonia were considered more suitable for possible introduction of NCC for the repair of historical paper artifacts. This evidence was obtained by applying optical/polarized light microscopy observation and dynamic light scattering (DLS) results.

International audience; A variety of techniques were used to investigate flax yarns sampled from four selected Italian paintings on canvas dated between the 17th and 18th centuries and compare them with a modern flax yarn. The goal was to establish their state of preservation and highlight the critical issues thanks to a combined approach that used SEM, atomic force microscopy, nanoindentation, nuclear magnetic resonance, second harmonic generation imaging microscopy and FTIR spectroscopy. The condition of the flax fibres was assessed, and the results showed that two of the four canvases were in a generally good state of preservation, while the other two exhibited signs of biological attack and brittleness due to a previous relining intervention.

Opuntia cladodes are a typical vegetable waste, from which mucilage in gel form can be extracted. This work proposes blending it with a self-produced thermoplastic starch (TPS), originating from potato starch with a high content in glycerol (ca. 30%). Three methods were compared for extraction, bare maceration (MA), mechanical blending (ME) and mechanical blending following maceration (MPM) to produce films with an approximate thickness of 150 &mu, m. For the comparison, tensile testing, differential scanning calorimetry and scanning electron microscopy were used. The MPM process proved the most effective, not only for extraction yielding, but also to obtain a larger deformation of the samples with respect to the one allowed by the pure TPS films. A considerable plasticization effect was observed. Despite this, the mechanical performance is still not completely satisfactory, and the expected effect of the calcium and magnesium salts contained in the mucilage to improve the rigidity of the TPS film was not really revealed. Prospected improvements would concern the fabrication process and the investigation of other possible loading modes and sample geometries.

This work aimed at evaluating the possible use of several organic compounds as novel conservation products against the biocolonization of cultural heritage materials. In a first step, the antifungal activity of 10 selected essential oil (EOs) constituents was tested against a strain of Aspergillus niger collected from a Roman mural painting (Pompeii, Italy). According to antifungal assays, thymol, eugenol and cinnamaldehyde provided a strong and enduring inhibition effect. These properties open the way to the possible exploitability of EOs constituents for middle and long-term protection applications. In this perspective, the three compounds were exposed to different light conditions with the purpose of assessing their stability under photo-oxidation conditions. After ageing, Fourier transform infrared spectroscopy (FTIR) analysis and in vitro antifungal assays were performed. The collected results proved that light exposure had a critical negative effect on the antifungal capability of cinnamaldehyde samples. On the contrary, composition and properties of eugenol and thymol were not affected by ageing, confirming their possible use in the future development of long-lasting conservation products.

Opuntia cladodes are a typical vegetable waste, from which mucilage in gel form can be extracted. This work proposes blending it with a self-produced thermoplastic starch (TPS), originating from potato starch with a high content in glycerol (ca. 30%). Three methods were compared for extraction, bare maceration (MA), mechanical blending (ME) and mechanical blending following maceration (MPM) to produce films with an approximate thickness of 150 μm. For the comparison, tensile testing, differential scanning calorimetry and scanning electron microscopy were used. The MPM process proved the most effective, not only for extraction yielding, but also to obtain a larger deformation of the samples with respect to the one allowed by the pure TPS films. A considerable plasticization effect was observed. Despite this, the mechanical performance is still not completely satisfactory, and the expected effect of the calcium and magnesium salts contained in the mucilage to improve the rigidity of the TPS film was not really revealed. Prospected improvements would concern the fabrication process and the investigation of other possible loading modes and sample geometries.

The progress and stereochemistry of Boyer's reaction were analyzed using several simple, chiral, alcoholic substrates, a variable amount of BiBr3 and different solvents. Basic solvents inhibit the reaction, while cyclohexane works very well; thus, it was our choice for the present study. In contrast to previous works, BiBr3 behaves as a true catalyst, being not consumed during the reaction. Although poisoning of the catalyst occurs to some extent, it does not prejudice the reaction yields (>90%). Gas chromatography/mass spectrometry (GC-MS) monitoring of the reaction revealed that, for example, in the presence of alcohol , isomeric ethers transetherificate to . We propose a unifying mechanistic model for both Boyer's and transetherification reactions, in which the electronic properties of n-adducts intermediates, formed by combination of bismuth(III) of BiBr3 and oxygen atoms of alcohols and ethers, play the key role for both the reactivity and the stereochemical outcome of the reaction.

The paper presents an experimental study on mortar samples taken from historic and monumental buildings damaged or collapsed following the seismic events in Central Italy (2016-2017). Sixty-one samples were analysed via a set of diagnostic investigations to characterize the mortar and correlate it with the performance of the masonry. The techniques used were: X-ray diffraction, scanning electron microscopy and microanalysis, differential scanning calorimetry, calcimetry, Fourier-transform infrared spectroscopy, soluble salt analysis by conductimetry and dosage of anionic species by ion chromatography, particle-size analysis, direct shear. Microstructural characterization of the mortars revealed differences in mortar composition depending on their provenance. In particular the samples from Norcia contained large quantities of calcite while in the mortars from Pretare, dolomite was identified. In the case of Amatrice, only a few samples showed crystalline phases and compounds ascribable to binders. These results were largely confirmed by the other chemical and physical analysis performed, and mechanical tests also demonstrated low cohesion. The tests showed that in almost all the samples, poor quality mortars were used, and, in some cases, underachieving binder mortar.

Mortar quality is a fundamental parameter to take into account when studying the structural behavior of masonry, especially under seis− mic actions. Separation between the leaves of rubble masonry can occur, inducing the partial or total collapse of the construction. A good quality mortar is essential to delay/prevent the separation of leaves, but often, especially in ancient building with a cultural value, mor− tars have low binder capabilities. The paper presents an experimental investigation on mortar specimens taken from buildings of a little municipality in Marche region, Arquata del Tronto, heavily damaged by recent earthquakes in Central Italy (2016−2017). Both diagnostic techniques as X−Ray diffrac− tion, Fourier−Transform infrared spectroscopy and calcimetry, and mechanical test as compression tests were carried out in order to cor− relate the obtained values with the performance of the original masonry.

This work expands the study of the conservation of organic specimens of historical and artistic interest, assessing both biological and physical-chemical conservation requirements, in order to arrive at the tangible solution, set out herein. The results of the experiment carried out on the prototype demonstrated the performance in terms of gas tightness achieved by the system, as well as the ability to maintain stable storage parameters for a very long period of time. During the course of the study, the chemical compounds emitted by the materials used in construction were taken into consideration, and the effect of the climatic variations present in museum exhibition areas, archives or churches on the physical properties was monitored. This study saw the development of two innovative patented technologies (IT-1398645 and IT-1425729) applied to the construction of two cases, designed to conserve and display the mummies of Rosalia Lombardo (1918–1920 AD) in Palermo, Italy and Princess Anna of Bavaria (1319 AD) in Kastl, Germany.

This study is aimed at evaluating physical and chemical parameters which are considered as the most appropriate for the long-term preservation of mummies, distinguishing between those which are on display in museums and those which are preserved in storage rooms. The objective of this study is also to compare and discuss differences among the most widely known guidelines and norms of the field and to highlight the single phenomena which affect the decay of this kind of cultural asset.

The progress and stereochemistry of Boyer's reaction were analyzed using several simple, chiral, alcoholic substrates, a variable amount of BiBr3 and different solvents. Basic solvents inhibit the reaction, while cyclohexane works very well; thus, it was our choice for the present study. In contrast to previous works, BiBr3 behaves as a true catalyst, being not consumed during the reaction. Although poisoning of the catalyst occurs to some extent, it does not prejudice the reaction yields (90%). Gas chromatography/mass spectrometry (GC-MS) monitoring of the reaction revealed that, for example, in the presence of alcohol , isomeric ethers transetherificate to . We propose a unifying mechanistic model for both Boyer's and transetherification reactions, in which the electronic properties of n-adducts intermediates, formed by combination of bismuth(III) of BiBr3 and oxygen atoms of alcohols and ethers, play the key role for both the reactivity and the stereochemical outcome of the reaction.

The stereoselectivity of a series of 1-aryl-1,2-epoxycyclohexanes substituted on the phenyl group was determined in acid methanolysis in the condensed phase (0.2 N H2SO4–MeOH) and in the reaction with MeOH in the gas phase under catalysis by a gaseous Bronsted acid (D3+). The results obtained show the presence of a clear Hammett-type dependence of the syn/anti adduct ratio on the Brown σ+ of the substituent on the phenyl group, thus confirming the validity of the ion–dipole pair mechanism in order to rationalize the stereochemical behavior of 2-aryloxiranes in opening reactions under acidic conditions. Only in the cases of the p-OMe- and p-NO2-substituted epoxides, does an SN1 and an SN2 process, respectively, appear to be involved. Copyright © 2004 John Wiley & Sons, Ltd.

The enantioselective interactions between chiral tetra-amidic receptors and nucleosides have been investigated by the ESI-IT-MS and ESI-FT-ICR-MS methodologies. Configurational effects on the CID fragmentation of diastereomeric [M(H)(2)•H•A](+) aggregates (A = 2'-deoxycytidine dC, citarabine (ara-C) were found to be mostly offset by isotope effect in [S(X)(2)•H•A](+) (X = H, D) differently from the results obtained on the analogues (A = cytidine C and gemcitabine G). This result points the involvement of two different nucleoside/tetraamide isoforms. The structural differences of the [M(H)(2)•H•A](+) (A = C and G) complexes vs. the [M(H)(2)•H•A](+) (dC and ara-C) ones is fully confirmed by the kinetics of their uptake of the 2-aminobutane enantiomers, measured by FT-ICR mass spectrometry. Indeed, uptake of the 2-aminobutane enantiomers by [M(H)(n)•H•A](+) (n = 1,2; A = dC and ara-C) complexes is reversible, while that by [M(H)(n)•H•A](+) (n = 1,2; A = C and G) is not. The most encouraging result concerning the measured fragmentation and kinetic differences between C and ara-C, that are just epimers, indicates the possibility to subtly modulate the non-covalent drug/receptor interactions, through the electronic properties of the 2'-substituent on the nucleoside furanose ring, and furthermore on its three-dimensional position.

The acid-catalyzed addition of CH3(18)OH to 2-methylene-adamantanes bearing a chlorine atom in the 4-equatorial (1e) or 4-axial (1a) position has been investigated in the gas phase, at 760 Torr, in the 40-120 degrees C temperature range. Two different experimental approaches were employed: (1) by adding neutral CH3(18)OH to the 2-methyl-4-Cl-adamant-2-yl cation, generated by protonation of the corresponding 2-methylene-4-Cl-adamantane (the extracomplex reaction) and (2) by reaction of 2-methylene-4-Cl-adamantane with CH3(18)OH2+, generated by methylation of H2(18)O (the intracomplex reaction). The crucial role of the nature of the noncovalent intermediates involved along the reaction coordinates emerges from the difference between the results obtained in the extracomplex and intracomplex reactions for both substrates investigated. The kinetic and stereochemical results indicate that the 4-Cl substituent plays a different role depending on its equatorial or axial orientation. Examination of the experimental results in the light of MP2/6-31G* theoretical calculations provides important information about the intrinsic factors governing the facial diastereoselectivity of trigonal carbocations. The effects due to differential face solvation phenomena emerge from the comparison of the present gas-phase results with those obtained from strictly related studies in solution.

The R2PI-TOF spectra of supersonically expanded rare gas/chiral arene heteroclusters have been rationalized in terms of the distortion of the pi-electron density reflecting the different dipole and quadrupole momenta induced in the rare gas atoms by interaction with the opposite pi-faces of the chiral arene itself.

The regioselectivity of the addition reaction of MeOH both in the condensed phase (MeOH/H2SO4) and in the gas-phase (MeOH/D3+) was examined in a series of activated aziridines. The results indicate that gas-phase operating conditions are particularly favorable for the occurrence of D+-mediated chelated bidentate species, which influence the regioselectivity of the opening process. In the condensed phase, the chelating MeOH/LiClO4 protocol turned out to be decidedly less effective for regioselectivity and also in determining the composition of the reaction mixture.

The mechanism and stereochemistry of the intracomplex solvolysis of proton-bound complexes [Y...H...M]+ between M = CH3 (18)OH and Y = 1-arylethanol [(S)-1-(para-tolyl)ethanol (1S), (S)-1-(para-chlorophenyl)ethanol (2S), (S)-1-(meta-alpha,alpha,alpha-trifluoromethylphenyl)ethanol (3S), (S)-1-(para-alpha,alpha,alpha-trifluoromethylphenyl)ethanol (4S), (R)-1-(pentafluorophenyl)ethanol (5R), (R)-alpha-(trifluoromethyl)benzyl alcohol (6R), and (R)-1-phenylethanol (7R)] have been investigated in the gas phase (CH3F; 720 Torr) in the 25-140 degrees C temperature range. Gas-phase solvolysis of [Y...H...M]+ (Y=2S, 3S, 4S, and 7R) leads to extensive racemization above a characteristic temperature t(#) (e.g. at t(#)60 degrees C for 7R), whereas below that temperature the reaction displays a preferential retention of configuration. Predominant retention of configuration is instead observed in the intracomplex solvolysis of [Y...H...M]+ (Y=1S, 4S, 5R, and 6R) with the temperature range investigated (25or= Tor= 120 degrees C). These results indicate that the intracomplex solvolysis proceeds through the intermediacy of the relevant benzylic cations (Bz+), which is electrostatically coordinated to a H2O and a CH3 (18)OH molecule (a pure SN1 mechanism). The obtained gas-phase mechanism is discussed in the light of related solution data. It is concluded that the stereochemistry of unimolecular solvolytic reactions is determined by the lifetime and the dynamics of the species involved and, if occurring in solution, by the nature and the dynamics of the solvent cage as well.

[isomers: see text] The kinetics and stereochemistry of the protonation-induced unimolecular isomerization of (R)-1-D1-3-(p-fluorophenyl)butane have been investigated in the gas phase at 40-100 degrees C and 70-760 Torr. This process leads to the formation of the relevant meta and ortho isomers with partial racemization of the migrating sec-butyl moiety. Complete racemization is observed, instead, when the isomerization reaction involves a 1,2-H shift in the moving alkyl group. These results, together with the relevant activation parameters, fully confirm the previous evidence of the occurrence in the alkyl cation/arene PES of noncovalent eta-type intermediates of defined structure and stability, lying well below the classical pi-complexes, as confirmed by ab initio calculations. Their crucial role in determining the positional selectivity of gas-phase electrophilic aromatic substitutions clearly emerges from the comparison of the present results with the site selectivity measured in the corresponding bimolecular arene alkylation carried out at the same temperatures and pressures.

The regiochemical behavior of a series of aliphatic open chain epoxides bearing a heterofunctionality in an allylic or homoallylic relationship has been examined in the opening reaction with MeOH under both condensed and gas phase operating conditions. The results indicate that the proton (actually D+) possesses in the gas phase intrinsic chelating properties which are even superior than those of Li+ in the condensed phase.

The kinetics and the stereochemistry of the protonation-induced unimolecular isomerization of (S)-(+)-1-D(1)-3-(p-tolyl)butane have been investigated in the gas phase in the 100-160 degrees C range. The process leads to the almost exclusive formation of the relevant meta isomer with complete racemization and partial 1,2-H shift in the migrating sec-butyl group. These results, together with the relevant activation parameters, point to the occurrence of low-energy, tightly bound isomeric sec-butyl cation/toluene complexes of defined structure and stability along the isomerization coordinate. The existence and the eta(1)-type structure of these low-energy intermediate species are confirmed by ab initio calculations on closely related systems at the MP2(full)/6-311++G**//HF/6-31+G** level of theory. Their role in the relevant energy surface clearly emerges from the comparison of the present results with those concerning sec-butylation of toluene carried out under comparable experimental conditions.

The regiochemical behavior of pairs of regio- and diastereoisomeric epoxides derived from the 3,4,5,6-tetrahydro-2 H -pyrane system, bearing an acetal group as the remote functionality, was determined in the acid methanolysis in the condensed phase (cd-phase) and in the reaction with MeOH in the gas-phase using a gaseous acid (D 3 + ), as the promoting agent. With only one exception, the results obtained in the opening process of these epoxides indicate the incursion in the gas-phase of D + -mediated chelated bidentate species able to modify the regiochemical result found in the methanolysis in the cd-phase.

The regiochemical behavior of the pairs of diastereoisomeric activated aziridines 1 – 8 deriving from the cyclohexane system, bearing a remote O -functionality, was determined in the acid methanolysis in the condensed phase (cd-phase) and in the reaction with MeOH in the gas-phase using a gaseous acid (D 3 + ) as the promoting agent. The results obtained in the opening process of the cis diastereoisomers indicate the constant incursion in the gas phase of D + (corresponding to H + )-mediated chelated bidentate species able to modify the regiochemical result found in the methanolysis in the cd-phase.

The regiochemical behavior of cyclohexene oxides bearing a remote O -functionality was determined in the gas-phase in opening reactions with MeOH, using a gaseous acid (D 3 + , C n H 5 + , Me 2 F + ) as the promoting agent. The results obtained indicate the incursion in the opening process in the gas phase of H + (or D + )-mediated chelated bidentate species completely absent in the corresponding reactions (methanolysis) carried out in the condensed phase.

The regiochemical behavior of cyclohexene oxides bearing a remote O -functionality was determined in the gas-phase in opening reactions with MeOH, using a gaseous acid (D 3 + , C n H 5 + , Me 2 F + ) as the promoting agent. The results obtained indicate the incursion in the opening process in the gas phase of H + (or D + )-mediated chelated bidentate species completely absent in the corresponding reactions (methanolysis) carried out in the condensed phase.

The ring-opening reactions with MeOH of the title benzocondensed 2-aryl oxiranes 6 and 7a,b both in the condensed (methanolysis) and in the gas phase were examined, obtaining in all cases a good Hammett-type linear correlation. Results indicate that the secondary or tertiary nature of the benzylic oxirane carbon is not responsible for the different stereochemical behavior so far encountered in different 2-aryl oxirane systems under the same operating conditions.