Abstract

The investigation focused on the deterioration of the walls in the hypogeum of "San Pietro Barisano" rupestrian church, located in the Matera-Sassi (Southern Italy), one of the UNESCO World Heritage sites. The study evaluated the biocide activity of a mixture of natural glycoalkaloids (GAs) extracted from the unripe fruit of Solanum nigrum and applied to clean a hypogeum wall surface in the church affected by bio-patinas. The analyzed bio-patina, collected before treatment and, at pre-established times, after treatment, showed changes in chemical composition detected by XPS, accompanied by visible discoloration and biological activity variation. The biocidal action of the glycoalkaloids mixture, directly employed on the wall surface, was effective after about four weeks for most bio-patina colonizers but not for the fungal species that can migrate and survive in the porosities of the calcarenite. Consequently, the cleaning procedure requires the integration of fungicidal actions, combined with the consolidation of the surfaces, to obtain complete bioremediation and avoid subsequent biological recolonization. SEM images and associated microanalysis of pretreated bio-patina have revealed the biocalcogenity of some autochthonous microorganisms, thus preluding to their eventual isolation and reintroduction on the wall surface to act as consolidants once the bio-cleaning phase has been completed.

The application of Low-Temperature Plasmas has shown great potential as an effective and alternative tool for microbial inactivation in recent years. Nevertheless, further investigations are required to fully understand the possible factors influencing these processes. The present study aims to investigate the effectiveness of square wave modulated Volume Dielectric Barrier Discharge on the direct inhibition of conidial germination in five different fungal species, various discharge conditions, and medium composition. The five different fungal species used were Botrytis cinerea, Monilinia fructicola, Aspergillus carbonarius, Fusarium graminearum, and Alternaria alternata. On water agar, the inhibition of Botrytis cinerea was influenced by the applied voltage, which mainly reflects the uniformity of the treatment. Under the selected voltage condition, the inhibition increased with treatment duration and decreased with fungal spore complexity. B. cinerea and M. fructicola, with unicellular conidia and low melanin content, showed similar behaviour and high sensitivity to the treatment. F. graminearum and A. alternata, both having multicellular conidia, were more resistant to the plasma treatment and showed different sensitivity likely due to different content in melanin. However, after 1 min of treatment, complete inhibition of conidial germination was achieved for all the tested species. Inhibition of A. carbonarius conidia on different agarized media containing dextrose or malt extract was influenced by the complexity and composition of the medium, being potato dextrose agar that more hindered the plasma efficacy. Each medium exhibited a different electrical response studied by Electrical Impedance Spectroscopy and morphology observed by Scanning Electron Microscopy images. These differences translated into a different response to the applied electrical field, influencing plasma generation and uniformity.

The present study reports the conservative first aid concerning the human cranium known as the "Skull with Ears", which is conserved in the crypt of Santa Luciella ai Librai's church in Naples, Italy. These remains have historically been worshipped by devotees within the cult of the "abandoned souls". The skulls were "adopted" by the Neapolitan population and treated with particular care in exchange for divine favors. The critical preservation status of the "Skull with ears" required a multidisciplinary approach aimed at defining the taphonomy and anthropological features of the cranium, while determining the state of its conservation by using a multi-analytical approach. Multispectral imaging, 3D modeling, X-ray imaging, microscopical observations, and microbiological tests enabled the documentation of the cranium while assessing this state of conservation. Electron scanning microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR) in the attenuated total reflectance (ATR) mode, and radiocarbon dating allowed for essential data to be obtained on the cranium's history and constituent components. The results that were obtained from both the analysis of the cranium and the environmental monitoring of the crypt showed the advanced degradation of the bones due to a significant bacterial attack, which was facilitated by the inadequate environmental conditions at the site of conservation. The acquired data enabled the definition of the most suitable conservation strategy and the securing of the cranium.

In this work we produced Yb:YAG using different procedures and process parameters. We observed, by SEM analysis, that when the transmittance is above 75 %, the main type of defect is porosity. SEM is the typical characterization for transparent ceramics, but it is not fully adequate when the number of defects is low. For transparent ceramics, even a small amount of defects heavily influences the final optical quality. For example, YAG with density of 99 %, or even 99.9 %, is not transparent. Stuer et al. were able to reconstruct the pore distribution in transparent alumina using a combination of SEM and FIB in three dimensions, but the analysis is destructive and the volume analysed was very small (30 µm³). It is therefore important to find alternative techniques that can allow to investigate a larger volume of material. We developed a fast and non-destructive method based on the use of focus stacking with a digital optical microscope. The resulting stacked image shows all the defects present in the portion of volume analysed (~0.022 mm3 or 22×106 µm3). Image analysis was performed to extract information about number of pores and their size. To present the potential of this novel analytical technique we analysed samples of Yb:YAG and it was possible to correlate the transmittance in the sample with the number of the pores and get information about the influence of the process on the average pore size.

In this study, antibacterial polymer blends based on Polyvinyl Chloride (PVC) and Polystyrene-Ethylene-Butylene-Styrene (SEBS), loaded with the ionic liquid (IL) 1-hexadecyl-3-methyl imidazolium 1,3-dimethyl 5-sulfoisophthalate (HdmimDMSIP) at three different concentrations (1%, 5%, and 10%), were produced. The IL/blends were characterized by their thermo-mechanical properties, surface morphology, and wettability. IL release from the blends was also evaluated. The agar diffusion method was used to test the antibacterial activity of the blends against Staphylococcus epidermidis and Escherichia coli. Results from thermal analyses showed compatibility between the IL and the PVC matrix, while phase separation in the SEBS/IL blends was observed. These results were confirmed using PY-GC MS data. SEM analyses highlighted abundant IL deposition on PVC blend film surfaces containing the IL at 5-10% concentrations, whereas the SEBS blend film surfaces showed irregular structures similar to islands of different sizes. Data on water contact angle proved that the loading of the IL into both polymer matrices induced higher wettability of the blends' surfaces, mostly in the SEBS films. The mechanical analyses evidenced a lowering of Young's Modulus, Tensile Stress, and Strain at Break in the SEBS blends, according to IL concentration. The PVC/IL blends showed a similar trend, but with an increase in the Strain at Break as IL concentration in the blends increased. Both PVC/IL and SEBS/IL blends displayed the best performance against Staphylococcus epidermidis, being active at low concentration (1%), whereas the antimicrobial activity against Escherichia coli was lower than that of S. epidermidis. Release data highlighted an IL dose-dependent release. These results are promising for a versatile use of these antimicrobial polymers in a variety of fields.

Internal prosthesis and grafts are currently made of Ti alloys, stainless steels and Co-Cr alloys. In spite of excellent biocompatibility, they show some drawbacks that concern their mechanical properties (e.g. elastic modulus) and the need of secondary surgery for removing the implant. For this reason, a growing attention has been focused on biodegradable materials that can be absorbed into the body after tissue remodelling. In particular, Mg alloys are promising candidates for temporary implants thanks to their high biocompatibility, biodegradability and good mechanical properties that match those of human bone. In this work, the surface modifications of biodegradable AZ31 alloy were analysed after immersion for 15 days in a physiological solution (NaCl 0.09%) by using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. XPS analysis of the surface of as-supplied AZ31 alloy showed the presence of MgO, whereas after immersion in the physiological solution, only Mg (OH)(2) was detected. The result has been discussed with reference to literature data. From the photoemission spectra and quantitative analysis, a small amount of Ca (about 2 wt%) was also detected.

Titanium and its alloys are widely employed in commercial dental devices. Because the surface morphology and chemical composition of Ti-based dental implants play a relevant role in osseointegration, three different commercial threaded implants have been investigated by scanning electron microscopy and X-ray photoelectron spec- troscopy (XPS). The Implants A and C were made of pure Ti whereas the Implant B was made of Ti6Al4V alloy. Obtained results evidenced the common features and dif- ferences due to specific process parameters used in the treatments of mordanting and sandblasting for surface roughening. Implant A exhibits a uniform surface cov- ered by very small dimples of about 1-2 ?m. The surface of Implant B is not homoge- neous: The thread tops present an irregular morphology (dimples size >10 ?m) while finer dimples (about 1 ?m) are observed along the thread flanks and valleys. Implant C shows an irregular morphology with dimples of different sizes and shapes distrib- uted on thread tops, flanks, and valleys. XPS analyses revealed the presence of metal oxides: TiO2 in all the implants; Al2O 3 and V2 O5 only in the implant B. Moreover, these results demonstrated that Mg2SiO 4 is present on the surface of Implant A, probably due to a specific preparation process. Obtained results have been discussed on the basis of the factors promoting the osseointegration.

Many researches have been devoted to rechargeable power generators that can store (but also release) energy. This availability is ensured through (e. g.) the oxygen evolution reaction (OER). However, (i) large values of the overpotentials and (ii) a progressive detriment of the anode (graphite) electrode limit the ultimate device. In view of enhancing the electrode performances, graphite was protected by following different strategies, which oblige to follow precise preparation protocols. Here, we prove that a thin layer of free-base porphyrin molecules is able to protect the underneath graphite electrode from detriment even if many (about 100) electrochemical cycles are performed.

The objective of this work is the application of innovative method for metals recovery from metalliferous mine water released from the flooded siderite mine Ni?ná Slaná. Although the metals contained in mine drainage are considered environmental pollutants, they may also be valuable resources. Conventional chemical precipitation processes produce huge amounts of sludge with storage and management requirement, without possibility of waste metals processing. This study comprehensively investigated the selective recovery of Fe and Mn from mine water. After oxidation and partial precipitation of iron using hydrogen peroxide, precipitation by sodium hydroxide was applied to the residue iron removal from mine water. In the next step potassium permanganate was used to eliminate manganese by oxidative precipitation. ORP and pH of the solutions were recorded in the course of oxidation/precipitation processes. The morphology and elemental composition of the products were studied by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The recovery efficiencies of Fe and Mn from mine water reached 98.4 % and 96.7 %, respectively. Targeted metals were removed with high selectivity to levels that meet water quality criteria for save discharge to the environment.

Wood species identification and characterization of its weathering processes are crucial steps in the scientific approach of conservation of wooden cultural heritage. Many precious wooden objects of ancient Egypt are largely present in museums, nevertheless relatively little information is available concerning the nature of timber used and on their status of conservation. To address this gap, the wooden species of three relevant archaeological wood objects (statue, box, and coffin) arising from different Egyptian archaeological sites dated from the Old Kingdom (2,686-2,181 BC) to New Kingdom (1,550-1,069 BC) were deeply studied. Five hardwood and softwood species were identified belonging to Tamarix mannifera, T. gennessarensis, Ficus sycomorus, Vachellia nilotica, and Cedrus sp. Such data confirmed the recurrence of Vachellia and Tamarix among the most common timbers found in ancient Egypt. Scanning electron microscope, Fourier transform spectroscopy, and synchrotron x-ray radiation diffraction were conducted to evaluate the archaeological wood deterioration. The formation of microcracks, biological degradation patterns (fungal colonization), or chemical characterization (accumulation of salts on and in-between wooden cells) were detected. SEM micrographs showed the presence of fungal hyphae and conidial spores on the wooden cells. Significant changes in the chemical wood composition and decrease in the crystallinity index were detected.

Two wild populations of Helichrysum (Mill.) located at Elba Island (Tuscan Archipelago, Central Italy) were morphologically and phytochemically analyzed to taxonomically identify H. litoreum (population A) and H. italicum subsp. italicum (population B). Micromorphological and histochemical analyses were performed on the indumentum using Scanning Electron Microscope (SEM) and Light Microscope (LM). Morphometric analyses on vegetative and reproductive traits were also conducted. Finally, a chemotaxonomic analysis was carried out on the terpene profile of flowers, leaves and bark tissues using gas chromatography (GC-MS). Results suggested that morphological discriminant traits were mainly in leaves and cypselae glandular tissues. Phytochemical analysis indicated that a high relative content of ?-pinene and ?-caryophyllene were the main markers for population A, while a high relative content of neryl-acetate, ?-curcumene, isoitalicene and italicene, especially in the terpene profile of bark tissue, were the main compounds for discriminating population B. The analysis suggested that the wild population A could be mainly ascribed to H. litoreum, whilst population B is defined by H. italicum.

The chemical homogeneity of single phase high-entropy AlB2-type Ti-Zr-Hf-TaTM diboride (TM = Cr, V, W, Mo), as well as Ti-Zr-Hf-Mo-W solid solutions was investigated using a new method based on the comparative examination of information provided by electron microscopy and structural parameters. The study of the densification behavior was accomplished, and strong correlations among densification rate-grain coarsening-long range chemical randomization were found. High-resolution synchrotron radiation X-ray diffraction supported by grain-scale chemical analyses by energy dispersive spectroscopy indicated that homogenization of the metals was incomplete, with direct impact on the refined lattice ?-strain. The chemical inhomogeneity was on the same length scale as the grain size, which makes it hardly detectable by typical chemical mapping using energy dispersive spectroscopy. Based on this analysis, the resulting ?-strain broadening is not an intrinsic property of the material, but strongly depends on its processing history.

Recently, due to environmental and sustainability issues, the scientific community has been attracted to renewable natural resources, even for the development of materials intended for structural applications. This work deals with the pre-treatment of a flax fiber fabric by exploring the effects of the exposure time to nitrogen plasma on the ultimate performance of polypropylene matrix composite laminates potentially usable for the realization of internal parts in the naval sector. Flax fabrics were treated with three different exposure times (5, 10, and 15 min) with the aim to improve the adhesion between the hydrophilic fibers and the hydrophobic matrix. At first, transverse and longitudinal wicking tests were carried out on the treated fabrics in order to evaluate the improvement of the absorption constants after the formation of reactive groups on their surface. The results collected so far in terms of fabric water uptake, tensile, and flexural properties as well as morphological aspects (SEM analysis) and damage evolution (ESPI technique), have indicated that the optimal pre-treatment time of the reinforcing fabrics is equal to 15 min. Compared to the laminate with untreated fabrics, the specimen with flax fibers treated for 15 min displays higher tensile properties with an increase of 6.8% and 22.31% in ultimate strength and modulus, respectively. More in general, the achievements of this research might be useful to extend the current range of applications of flax fibers even in industrial fields still dominated by conventional fibers.

Wildfires across the Mediterranean ecosystems are associated with safety concerns due to their emissions. The type of biomass determines the composition of particulate matter (PM) and gaseous compounds emitted during the fire event. This study investigated simulated fire events and analysed biomass samples of six Mediterranean species and litter in a combustion chamber. The main aims are the characterization of PM realized through scanning electron microscopy (SEM/EDX), the quantification of gaseous emissions through gas chromatography (GC-MS) and, consequently, identification of the species that are potentially more dangerous. For PM, three size fractions were considered (PM10, 2.5 and 1), and their chemical composition was used for particle source-apportionment. For gaseous components, the CO, CO2, benzene, toluene and xylene (BTXs) emitted were quantified. All samples were described and compared based on their peculiar particulate and gaseous emissions. The primary results show that (a) Acacia saligna was noticeable for the highest number of particles emitted and remarkable values of KCl; (b) tree species were related to the fine windblown particles as canopies intercept PM10 and reemit it during burning; (c) shrub species were related to the particles resuspended from soil; and (d) benzene and toluene were the dominant aromatic compounds emitted. Finally, the most dangerous species identified during burning were Acacia saligna, for the highest number of particles emitted, and Pistacia lentiscus for its high density of particles, the presence of anthropogenic markers, and the highest emissions of all gaseous compounds.

Background: Nucleopeptides are chimeric compounds of biomedical importance carrying DNA nucleobases anchored to peptide backbones with the ascertained capacity to bind nucleic acids. However, their ability to interact with proteins involved in pathologies of social relevance is a feature that still requires investigation. The worrying situation currently observed worldwide for the COVID-19 pandemic urgently requires the research on novel anti-SARSCoV- 2 molecular weapons, whose discovery can be aided by in silico predictive studies. Objective: The aim of this work is to explore by spectroscopic methods novel features of a thymine-bearing nucleopeptide based on L-diaminopropanoic acid, including conformational aspects as well as its ability to bind proteins, starting from bovine serum albumin (BSA) as a model protein. Moreover, in consideration of the importance of targeting viral proteins in the current fight against COVID-19, we evaluated in silico the interaction of the nucleopeptide with some of the most relevant coronavirus protein targets. Methods: First, we investigated via circular dichroism (CD) the conformational behaviour of this thymine-bearing nucleopeptide with temperature: we observed CD spectral changes, particularly passing from 15 to 35 °C. Scanning Electron Microscopy (SEM) analysis of the nucleopeptide was also conducted on nucleopeptide solid samples. Additionally, CD binding and preliminary in silico investigations were performed with BSA as a model protein. Moreover, molecular dockings were run using as targets some of the main SARS-CoV-2 proteins. Results: The temperature-dependent CD behaviour reflected the three-dimensional rearrangement of the nucleopeptide at different temperatures, with higher exposure to the solvent of its chromophores at higher temperatures compared to a more stacked structure at a low temperature. SEM analysis of nucleopeptide samples in the solid-state showed a granular morphology, with a low roughness and some thread structures. Moreover, we found through spectroscopic studies that the modified peptide bound the albumin target by inducing significant changes to the protein secondary structure. Conclusion: CD and preliminary in silico studies suggested that the nucleopeptide bound the BSA protein with high affinity according to different binding modes, as testified by binding energy scores lower than -11 kcal/mol. Interestingly, a predictive study performed on 3CL and other SARS-CoV-2 protein targets suggested the potential ability of the nucleopeptide to bind with good affinity the main protease of the virus and other relevant targets, including the RNAdependent RNA polymerase, especially when complexed with RNA, the papain-like protease, and the coronavirus helicase at the nucleic acid binding site.

In aerospace, it is of great interest to identify safe and low-cost manufacturing procedures to guarantee reliable and functional products. In this perspective, 3D printing is a fast and low-cost innovative technique to produce fiber-reinforced polymer matrix composites. This new technology, among other, forms short fiber composite that can be used as a shim material to fill voids left by manufacturing defects. The purpose of this work is to characterize reinforced composites developed for these applications and obtained with the innovative 3D printing technique.

Spartium junceum L. is a typical species of Mediterranean shrubland areas, also grown in gardens and parks as an ornamental. In recent years in Europe, S. junceum has been recurrently found to be infected by different subspecies and genotypes of the quarantine regulated bacterium Xylella fastidiosa (Xf). This work presents for the first time the anatomy of S. junceum plants that we found, by means of genetic and immunochemistry analysis, to be naturally infected by Xf subsp. multiplex ST87 (XfmST87) in Monte Argentario (Grosseto, Tuscany, Italy), a new outbreak area within the EU. Our anatomical observations showed that bacteria colonized exclusively the xylem conductive elements and moved horizontally to adjacent vessels through pits. Interestingly, a pink/violet matrix was observed with Toluidine blue staining in infected conduits indicating a high content of acidic polysaccharides. In particular, when this pink-staining matrix was observed, bacterial cells were either absent or degenerated, suggesting that the matrix was produced by the host plant as a defense response against bacterial spread. In addition, a blue-staining phenolic material was found in the vessels and, at high concentration, in the pits and inter-vessels. SEM micrographs confirmed that polysaccharide and phenolic components showed different structures, which appear to be related to two different morphologies: fibrillary and granular, respectively. Moreover, our LM observations revealed bacterial infection in xylem conductive elements of green shoots and leaves only, and not in those of other plant organs such as roots and flowers.

The recovery of the protein component and its transformation into protein hydrolysates, generally carried out chemically, gives great added value to waste biomasses. The production of protein hydrolysates through enzymatic catalysis would guarantee to lower the environmental impact of the process and raise product quality, due to the reproducible formation of low molecular weight peptides, with interesting and often unexplored biological activities. The immobilization of the enzymes represents a good choice in terms of stability, recyclability and reduction of costs. In this context, we covalently linked proteases from Aspergillus oryzae to polylactic acid an eco-friendly biopolymer. The hydrolytic efficiency of immobilized enzymes was assessed testing their stability to temperature and over time, and checking the hydrolysis of model biomasses (casein and bovine serum albumin). Soybean waste extracts were also used as proof of principle.

Polyethylene (PE) is the most abundant non-degradable plastic waste, posing a constant and serious threat to the whole ecosystem. In the present study, the fungal community of plastic wastes contaminating a landfill soil has been studied. After 6 months of enrichment, 95 fungi were isolated, mostly belonging to the Ascomycota phylum. They were screened under in vitro condition: most of fungi (97%) were capable of growing in the presence of PE powder (5-10 g L) as sole carbon source. Fusarium strains better tolerated high concentration of PE. Up to 13 strains were chosen for further degradation trails, where the process was monitored by respirometry tests and by observing changes in PE chemical and physical structure by FTIR analysis and SEM images. Major results were observed for Fusarium oxysporum, Fusarium falciforme and Purpureocillum lilacinum, as they caused strong oxidation phenomena and changes in the PE film morphology. Results suggested that the initial oxidation mechanisms targeted first the methyl terminal groups. Changes in the infrared spectra were strongly strain-dependent, denoting the activation of different degradation pathways. Through the SEM analysis, the actual damages provoked by fungi were observed, including swellings, pits and furrows, bumps and partial exfoliations. Considering the rising concern about plastic disposal worldwide, the ability of these fungi to colonize PE and utilize it as carbon source is of great interest, as no pretreatments and pro-oxidant stimulants were needed.