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Structural, thermal and functional characterization of metal-organic frameworks containing poly(pyrazolates)-based ligands for carbon dioxide adsorption
Full text linkThe dissertation proposes a comprehensive and systematic study of five new families of bis(pyrazolate) metal-organic frameworks (MOFs) for post-combustion CO2 capture and sequestration (CCS). Chapter I introduces the reader to the renowned problem of global warming, with a special focus on the role of CO2 and the different technologies for post-combustion CCS. MOFs state of the art in CO2 adsorption and the essential properties they should possess to be efficient in this application conclude the Chapter. Chapter II, after an overview on the use of pyrazolate-based MOFs, collects the syntheses of the studied compounds. The structural and thermal characterizations are reported in Chapter III. Chapter IV discusses the textural and adsorption properties, focusing on the influence of the different ligand functionalization. A comparison between the studied MOFs and the literature ones is then reported. Finally, starting from the most performing bis(pyrazolates) in terms of CO2 capacity and affinity, a series of mixed-ligand MOFs (MIXMOFs) is presented to further elucidate the role of linker functionalization in CO2 adsorption. MIXMOFs syntheses and full solid-state characterization are collected in Chapter V together with their CO2 adsorption capacity, affinity and selectivity. MIXMOFs performances are then compared to those of state-of-the-art materials developed for CO2 capture
Mortars: a complex material in cultural heritage. A multi-analytical procedure to characterize historical mortars.
Full text linkThis thesis deals with the identification of mortars composition in a cultural and historical context. In detail, the main concern was to collect information for proposing an analytical procedure able to define the mortar typology, balancing advantages, drawbacks, time and costs. In addition, several new techniques have been recently introduced in conservation science and the aim of this research is also to consider these new competences too.
To understand the interactions between components of mortars, in Chapter 1 a general overview of the subject is given with a description of the materials and of the historical background, based on the review of the large bibliography taken into account. In Chapter 2 the methods used for the preparation of the model samples and the final composition are explained. Moreover, the analytical techniques used in this research (optical microscopy and petrographic analysis, powder X-ray diffraction, infrared spectroscopy, Raman spectroscopy, environmental scanning electron microscopy, thermal analysis, mercury intrusion porosimetry and computed tomography) are described, specifying the setting of the instruments.
In Chapter 3 the results of the characterization of the raw materials and of the model samples are shown, the most meaningful results are shown for each technique. The discussion of the experimental data is presented in Chapter 4, and some analytical protocols are proposed, described and explained. In the last chapter, Chapter 5, the conclusions and the future development of this research are underlined
Synthesis and applications of chiral catalysts based on heterocyclic units
Full text linkThe present PhD Thesis was mainly focused on the synthesis and the applications of chiral catalysts based on heterocyclic units.
As an appendix of the manuscript, the work concerning my abroad period spent at the University of Glasgow is reported, whose research topic was the synthesis of benzoxazoles through a one-pot two-step procedure involving the use of first iron(III) and copper(I) catalysis for the second step. The fields of catalysis investigated are the Lewis Base, the Brønsted acid catalysis and finally the catalysis promoted by phosphoramidites.
As a contribution for the stereoselective Lewis Base catalysis, the synthesis and the resolution of TetraPh-Tol-BITIOPO (Chapter 1, 37) was carried out, whose application can be considered a further investigation of the huge potentialities of the 3,3’-bithiophenic enantiopure TetraMe-BITIOPO in Lewis-base catalysed Lewis-acid mediated reactions.
For what concern Brønsted acid catalysis, a new chiral phosphoric acid based on a decahydroquinoxalinic scaffold bearing in the position 2 and 3 two thienylic units (Chapter 2, 19) was synthesized and tested in two preliminary stereoselective organocatalytic transformations. Based on the same decahydroquinoxalinic backbone, we decided to design a new heterocyclic- based diphosphinoxide (Chapter 2, 42).
In Chapter 3, a new heterocyclic phosphoramidite based on a 3,3’-bithiophenic scaffold (L6) was synthesized and employed in combination with a copper salt in some catalytic stereoselective 1,4- additions of diethyl zinc to enones and trisubstituted nitroalkenes
Characteristics and processes of SMEs internationalization: from opportunities and constraints towards the development of strategic networks
No full textThe current thesis aims to provide a comprehensive outlook on the small and medium-sized enterprises’ (SMEs) internationalization-related phenomena, by advancing a gradual approach, setting the state-of-the-art as a building block and then passing to the in-depth analysis of underlying issues through articulate empirical studies. In line with this overall approach, the three chapters composing the thesis address three main research objectives: RO1. to identify and discuss the opportunities and constrains apposite for SMEs internationalization process, laying emphasis on the EU context; RO2. to investigate in-depth the influence of the managerial mindset (i.e., the global mindset versus the psychic distance) on the international business performance of SMEs; RO3. to fathom the relational design and methodology of knowledge sharing within SMEs strategic networks as a prerequisite of innovative performance. Accordingly, Chapter 1 theoretically investigates the opportunities and vulnerabilities apposite for SMEs, insisting on the internationalization conditions, and then empirically exploring the European initiatives meant to support them. Chapter 2 discusses two different facets of the internationalization strategies of SMEs, that is, the roles of psychic distance and global mindset within managerial dyadic collaborations. Chapter 3 approaches the affiliation of SMEs to strategic networks which have emerged as a fruitful path towards knowledge sharing with a view to enhance their innovative performance
Circulating cell-free DNA: a powerful biomarker for tumor management and a possible monitor tool in other pathological conditions.
Full text link‘Liquid biopsy’, i.e. the analysis of cfDNA in blood or body fluids, can give a live, ‘total’ image representing the entire heterogeneity of the system.
The application of high throughput analytical procedures, such NGS or ddPCR, are necessary to obtain reliable data on such a small amount of starting material.
Only few applications have achieved a clinical validation, due to the great variability in preanalytical procedures.
In our work we evaluated cfDNA with three different aims.
• Presence of mutation in a panel of 16 genes of the HR pathway in genomic and cfDNA in patients affected by breast cancer. We observed mutations in 3 out of 6 samples; in one case variant fraction in cfDNA was higer than in genomic DNA, probably due to limited ability to detect clonal heterogeneity in tissue.
• Monitoring tool for determining septic risk in patients undergoing dialysis. We detected in a sample, in accordance with the emoculture, a Staphylococcus strain together with Propionibacterium and Streptococcus strains. The detection of Burkholderia multivorans in another sample raised the possibility to identify those bacteria that take more than the canonical 5 days of emoculture to growth, or that completely do not grow in emoculture conditions.
• Detection of donor-derived cfDNA in transplanted patients. We identified more than 50% of donor derived polymorphisms just after reperfusion, falling down to 10% one day after surgery and then disappearing.
The possibility to cross our data with clinical parameters will help us to better describe the pertinence of our results to the effective status of patients.
In all the three settings, we are collecting other samples to have a broader amount of data that will allow us to perform statistical analysis to effectively validate our procedures
Ecological factors affecting the whale shark occurrence in Djibouti and presence of contaminants in the trophic web
No full textDjibouti is an important site where the whale shark (Rhincodon typus Smith 1828) regularly aggregates. Sharks gathering off the Djibouti coast are mostly juvenile males and target dense concentrations of zooplankton. However, only few studies has been carried out, leaving a knowledge gap on the main aspects of the whale shark ecology. Therefore, the main outcome of this study is to determine the environmental factors influencing the presence and distribution of this species in Djibouti. A robust understanding of the spatiotemporal distribution is required for developing successful management strategies for the whale shark protection in this area.
Moreover, whale sharks may be potentially exposed to relatively high levels of contaminants in Djibouti since they aggregate along one of the world busiest shipping route. Although the massive release of pollutants in African marine ecosystems and the deleterious effects on biota and humans, at present almost nothing is known about the contamination status of the Gulf of Aden, including Djibouti. The scarcity of studies includes all trophic levels, therefore, with a bottom-up approach, starting from zooplankton to get to predatory shark species, this study aims to characterize the trophic chain from an ecotoxicology point of view. With global decline in shark numbers, evaluating the extent of contaminant exposure is an urgent aspect since anthropogenic pollution may exasperate the current situation. Furthermore, since elasmobranchs are component of the artisanal fishery in Djibouti, and seafood consumption is as an important source of contamination for humans, this study aims to estimate for the first time the exposure health risks derived from shark consumption
Assessing bioaccumulation of chemicals in lacustrine food webs
No full textIn Italy, subalpine lakes provide fundamental ecosystem services; they support commercial and recreational fishing activities, they are important tourist destinations and they are intensively exploited for water supply in agriculture, industry and for drinking purposes.
In aquatic environment, DDTs and PCBs, perfluoroalkyl substances (PFASs) and mercury are ubiquitous contaminants, persistent and bioaccumulative.
The main aim of this Ph.D. study is to highlight the dynamics of redistribution of these selected chemicals with different physico-chemical properties in trophic webs of four major Italian southern alpine deep lakes (Lake Maggiore, Lake Como, Lake Iseo, Lake Garda) and a smaller one (Lake Mergozzo). Specifically, stable isotope analysis of carbon and nitrogen and trophic magnification factor were used, respectively, for the description of the trophic interactions to elucidate chemicals behaviour in biota and to model the biomagnification in food web.
In conclusion, notwithstanding the normative restrictions, DDTs, PCBs, PFOS and Hg still reached quantifiable concentrations in biota of the studied lakes. The analysis of trophic webs revealed that feeding relationships are not fixed and stable over time but they are probably ruled by the availability of resources. DDTs, PCBs and Hg biomagnify, as described in literature, confirming that sampling and analysis were correct; on the contrary, biomagnification for PFOS was not well characterised and further studies should be carried out.
Future researches should fill the gap of knowledge of contamination in Lake Garda and Lake Iseo that were not deeply investigated due to time schedule
Holistic ICT environments for effective mathematics teaching and learning
Full text linkTo understand the numbers world, each child must face a path that includes propaedeutic phases and only overcoming these phases will allow the child to consolidate processes before tackling new ones. If this does not happen, the child becomes self-convinced of ”not being able to understand math” and becomes increasingly aware of it throughout primary school. The transition to middle school may have a significant impact on a child, with specific difficulties or disabilities in learning mathematics, especially if his/her difficulties have not yet been identified. The present thesis studies the contributions of Information and Communication Technology (ICT) in supporting various aspects of mathematical teaching and learning. A multidimensional approach was used. In the first part, empirical studies assessed the effectiveness of digital tools to identify individual differences based on cognitive profiles and emotional responses associated with math performance in children from Northern Italy. In the second part a meta-analysis and systematic review analysis were carried out to evaluate the effectiveness of interventions supporting math learning by means of ICT in the school and home environments respectively. Altogether the thesis indicates that designing holistic ICT environments proves successful for effective mathematics teaching and learning not only for typically developing children but also for students in disadvantaged situations, including those suffering from dyscalculia
An Italian multicentre 2-step study in patients with MANECs of the gastro-entero-pancreatic tract treated with chemotherapy.
Full text linkBackground. Mixed adeno-neuroendocrine carcinomas (MANECs) are very rare malignancies. Due to their biological and clinical heterogeneity there is not a universally shared clinical approach.
Materials and Methods. Clinical records of patients with advanced MANEC of the gastro-enteropancreatic (GEP) tract from 4 Italian referral centres were retrospectively analysed. All the surgical specimens were centrally reviewed by a team of expert pathologists. Clinical and biological data were correlated with outcomes. Results. Fifty-one patients with histological diagnosis of GEPMANEC between 1995 and 2016 were included. Primary sites were colo-rectal in 32 patients, esophago-gastro-duodenal in 14, and pancreato-biliary in 5. At diagnosis (surgery) 74% were locally advanced. Seventy-one % developed distant metastases (24% sinchronous, 47% metachronous). Twenty-two % of patients (50% stomach) received pre-operative chemotherapy, 27% adjuvant (50% colo-rectal), and 12% peri-operative (45%, 50%, 80% fluoropyrimidines-based respectively). A first line therapy (57% fluoropyrimidines/oxaliplatin) was offered to the 45%
patients. Patients with a <55% Ki67 index in the NEC component had a significant longer OS than those with a ≥ 55% Ki67 (P=0.0004) regardless of the type of therapy. In the whole cohort, the median OS was 1.2 years (95% CI 0.8-1.6). Conclusion. This analysis suggested that the prognosis of GEP-MANECs is mainly driven by the NEC-component regardless of treatments. Since its descriptive design and various clinical management, it cannot either suggest a specific therapy or a real impact of chemotherapy on prognosis. However it produced solid hypotheses for future prospective-interventional studies in selected populations
QSAR models for the screening, prediction and refinement of PBT Properties of Contaminants of Emerging Concern.
No full textThe prompt identification of the adverse effects of Contaminant of Emerging Concern (CEC) is fundamental to ensure high protection level for human health and the environment. Persistent, Bioaccumulative and Toxic (PBT) compounds are chemicals of high concern and should be readily identified. The aim of this thesis is to propose an approach based on Quantitative Structure Activity Relationship (QSAR) models for the evaluation of the intrinsic environmental hazard of CECs. First, a screening of the potential PBT behavior of pharmaceuticals is performed by consensus approach. Results demonstrate a high agreement (i.e.86%) between the different QSAR models. Then, QSARs are developed to estimate acute toxicity of pharmaceuticals in aquatic species. All models have good fitting (R2>0.75) and predictivity (Q2EXT>0.68). An Aquatic Toxicity Index is proposed and modelled. Moreover, interspecies correlation models are also developed. Finally, QSARs for the prediction of whole-body human biotransformation Half-Lives are developed for organic chemicals. Predictions for the biotransformation potential are integrated in a mechanistic mass-balance multimedia environmental fate food-web model to estimate the Biomagnification Factor (BMF) in human in a tiered approach. The introduction of biotransformation strongly affects the calculation of BMF and the elimination processes related to biotransformation are predominant in the overall bioaccumulation