Study of materials and technology of ancient floor mosaics' substrate

Ancient pavements are composed of a variety of preparatory or foundation layers constituting the substrate, and of a layer of tesserae, pebbles or marble slabs forming the surface of the floor. In other cases, the surface consists of a mortar layer beaten and polished. The term mosaic is associated with the presence of tesserae or pebbles, while the more general term pavement is used in all the cases. As past and modern excavations of ancient pavements demonstrated, all pavements do not necessarily display the stratigraphy of the substrate described in the ancient literary sources. In fact, the number and thickness of the preparatory layers, as well as the nature and the properties of their constituent materials, are often varying in pavements which are placed either in different sites or in different buildings within a same site or even in a same building. For such a reason, an investigation that takes account of the whole structure of the pavement is important when studying the archaeological context of the site where it is placed, when designing materials to be used for its maintenance and restoration, when documenting it and when presenting it to public. Five case studies represented by archaeological sites containing floor mosaics and other kind of pavements, dated to the Hellenistic and the Roman period, have been investigated by means of in situ and laboratory analyses. The results indicated that the characteristics of the studied pavements, namely the number and the thickness of the preparatory layers, and the properties of the mortars constituting them, vary according to the ancient use of the room where the pavements are placed and to the type of surface upon which they were built. The study contributed to the understanding of the function and the technology of the pavements’ substrate and to the characterization of its constituent materials. Furthermore, the research underlined the importance of the investigation of the whole structure of the pavement, included the foundation surface, in the interpretation of the archaeological context where it is located. A series of practical applications of the results of the research, in the designing of repair mortars for pavements, in the documentation of ancient pavements in the conservation practice, and in the presentation to public in situ and in museums of ancient pavements, have been suggested.

Study of materials and interphases for electrochemical energy storage from renewable sources

Batteries should be refined depending on their application for a future in which the sustainable energy demand increases. On the one hand, it is fundamental to improve their safety, prevent failures, increase energy density, and reduce production costs. On the other hand, new battery materials and architecture are required to satisfy the growing demand. This thesis explores different electrochemical energy storage systems and new methodologies to investigate complex and dynamic processes. Lithium-ion batteries are described in all their cell components. In these systems, this thesis investigates negative electrodes. Both the development of new sustainable materials and new in situ electrode characterization methods were explored. One strategy to achieve high-energy systems is employing lithium metal anodes. In this framework, ammonium hexafluorophosphate is demonstrated to be a suitable additive for stabilizing the interphase and preventing uncontrolled dendritic deposition. Deposition/stripping cycles, electrochemical impedance spectroscopy, in situ optical microscopy, and operando confocal Raman spectroscopy have been used to study lithium metal-electrolyte interphase in the presence of the additive. Redox Flow Batteries (RFBs) are proposed as a sustainable alternative for stationary applications. An all-copper aqueous RFB (CuRFB) has been studied in all its aspects. For the electrolyte optimization, spectro-electrochemical tests in diluted solution have been used to get information on the electrolyte’s electrochemical behaviour with different copper complexes distributions. In concentrated solutions, the effects of copper-to-ligand ratios, the concentration, and the counter-ion of the complexing agent were evaluated. Electrode thermal treatment was optimized, finding a compromise between the electrochemical performance and the carbon footprint. On the membrane side, a new method for permeability studies was designed using scanning electrochemical microscopy (SECM). The Cu(II) permeability of several membranes was tested, obtaining direct visualization of Cu(II) concentration in space. Also, two spectrophotometric approaches were designed for SoC monitoring systems for negative and positive half-cells.

Study of variability and genetic structure of European populations of Myotis emarginatus and Myotis capaccinii (Chiroptera, Vespertilionidae)

The Geoffroy’s bat Myotis emarginatus is mainly present in southern, south-eastern and central Europe (Červerný, 1999) and is often recorded from northern Spain (Quetglas, 2002; Flaquer et al., 2004). It has demonstrated the species’ preference for forest. Myotis capaccinii, confined to the Mediterranean (Guille´n, 1999), is classified as ‘vulnerable’ on a global scale (Hutson, Mickleburgh & Racey, 2001). In general, the species preferred calm waters bordered by well-developed riparian vegetation and large (> 5 m) inter-bank distances (Biscardi et al. 2007). In this study we present the first results about population genetic structure of these two species of genus Myotis. We used two methods of sampling: invasive and non-invasive techniques. A total of 323 invasive samples and a total of 107 non-invasive samples were collected and analyzed. For Myotis emarginatus we have individuated for the first time a set of 7 microsatellites, which can work on this species, started from a set developed on Myotis myotis (Castella et al. 2000). We developed also a method for analysis of non-invasive samples, that given a good percentage of positive analyzed samples. The results have highlighted for the species Myotis emarginatus the presence on the European territory of two big groups, discovered by using the microsatellites tracers. On this species, 33 haplotypes of Dloop have been identified, some of them are presented only in some colonies. We identified respectively 33 haplotypes of Dloop and 10 of cytB for Myotis emarginatus and 25 of dloop and 15 of cytB for Myotis capaccinii. Myotis emarginatus’ results, both microsatellites and mtDNA, show that there is a strong genetic flow between different colonies across Europe. The results achieved on Myotis capaccinii are very interesting, in this case either for the microsatellites or the mitochondrial DNA sequences, and it has been highlighted a big difference between different colonies.

A study of new and more sustainable catalytic routes for the synthesis of adipic acid

The aim of my PhD research project was to investigate new and more sustainable routes, compared to those currently used, for the production of adipic acid (AA). AA is a very important chemical intermediate. The main use of AA is the production of Nylon-6,6 fibers, resins, polyesters, plasticizers. My project was divided into two parts: 1. The two-step oxidation of cyclohexene, where the latter is first oxidized into trans-1,2-cyclohexanediol (CHD) with aqueous hydrogen peroxide, and then the glycol is transformed into AA by reaction with molecular oxygen. Various catalysts were investigated in this process, both heterogeneous (alumina-supported Ru(OH)x and Au nanoparticles supported on TiO2, MgO and Mg(OH)2) and homogeneous (polyoxometalates). We also studied the mechanism of CHD oxidation with oxygen in the presence of these catalysts. 2. Baeyer-Villiger oxidation of cyclohexanone with aqueous hydrogen peroxide into ɛ-caprolactone, as a first step on the way to produce AA. Study on the mechanism of the uncatalyzed (thermal) oxidation of cyclohexanone were also carried out. Investigation on how the different heterogeneous catalysts affect the formation of the reaction products and their distribution was done.

Study of medicinal and food plants as a source of biologically active compounds.

In the last few decades, scientific evidence has pointed out the health-beneficial effects of phenolic compounds in foods, including a decrease in risk of developing degenerative and chronic diseases, known to be caused by oxidative stress. In this frame can be inserted research carried out during my PhD thesis, which concerns the phytochemical investigation of phenolic composition in sweet cherries (Prunus avium L.), apple fruits (Malus domestica L.) and quinoa seeds (Chenopodium quinoa Willd.). The first project was focused on the investigation of phytochemical profile and nutraceutical value of fruits of new sweet cherry cultivars. Their phenolic profile and antioxidant activity were investigated and compared with those of commonly commercialized cultivars. Their nutraceutical value was evaluated in terms of antioxidant/neuroprotective capacity in neuron-like SH-SY5Y cells, in order to investigate their ability to counteract the oxidative stress and/or neurodegeneration process The second project was focused on phytochemical analysis of phenolic compounds in apples of ancient cultivars with the aim of selecting the most diverse cultivars, that will then be assayed for their anti-carcinogenic and anti-proliferative activities against the hepato-biliary and pancreatic tumours. The third project was focused on the analysis of polyphenolic pattern of seeds of two quinoa varieties grown at different latitudes. Analysis of phenolic profile and in vitro antioxidant activity of seed extracts both in their free and soluble-conjugated forms, showed that the accumulation of some classes of flavonoids is strictly regulated by environmental factors, even though the overall antioxidant capacity does not differ in quinoa Regalona grown in Chile and Italy. During the internship period carried out at the Department of Organic Chemistry at Universidad Autónoma de Madrid (UAM), it was achieved the isolation of two pentacyclic triterpenoids, from an endemic Peruvian plant, Jatropha macrantha Müll. Arg., with bio-guided fractionation technique.

New synthetic bile acid analogue agonists of FXR and TGR5 receptors: Analytical methodologies for the study of their physico-chemical properties, pharmacokinetic activity and metabolism.

This thesis reports an integrated analytical approach for the study of physicochemical and biological properties of new synthetic bile acid (BA) analogues agonists of FXR and TGR5 receptors. Structure-activity data were compared with those previous obtained using the same experimental protocols on synthetic and natural occurring BA. The new synthetic BA analogues are classified in different groups according also to their potency as a FXR and TGR5 agonists: unconjugated and steroid modified BA and side chain modified BA including taurine or glycine conjugates and pseudo-conjugates (sulphonate and sulphate analogues). In order to investigate the relationship between structure and activity the synthetic analogues where admitted to a physicochemical characterization and to a preliminary screening for their pharmacokinetic and metabolism using a bile fistula rat model. Sensitive and accurate analytical methods have been developed for the quali-quantitative analysis of BA in biological fluids and sample used for physicochemical studies. Combined High Performance Liquid Chromatography Electrospray tandem mass spectrometry with efficient chromatographic separation of all studied BA and their metabolites have been optimized and validated. Analytical strategies for the identification of the BA and their minor metabolites have been developed. Taurine and glycine conjugates were identified in MS/MS by monitoring the specific ion transitions in multiple reaction monitoring (MRM) mode while all other metabolites (sulphate, glucuronic acid, dehydroxylated, decarboxylated or oxo) were monitored in a selected-ion reaction (SIR) mode with a negative ESI interface by the following ions. Accurate and precise data where achieved regarding the main physicochemical properties including solubility, detergency, lipophilicity and albumin binding . These studies have shown that minor structural modification greatly affect the pharmacokinetics and metabolism of the new analogues in respect to the natural BA and on turn their site of action, particularly where their receptor are located in the enterohepatic circulation.