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Mortars: a complex material in cultural heritage. A multi-analytical procedure to characterize historical mortars.
No full textThis 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
Statistical analysis of Dynamic Light Scattering data: from the Schätzel formulas to new approaches based on multi−tau Photon Counting Histogram and variance methods
No full textDynamic Light Scattering (DLS) is an optical technique aimed at the determination of the dimensions of small particles in a suspension in a range of diameters from about 1 nm to 1 μm. It consists in the measurement, at a fixed angle, of the scattered intensity radiation that, because of the Brownian motion of the particles, fluctuates stochastically with time. A DLS experiment provides the correlation function of the received intensity which is dependent from the coherence time of the fluctuations, that is related to the hydrodynamical radius of the particles that constitute the sample. In this thesis work, we analyzed the error bars associated to a correlation function and proposed a new approach for the analysis of Dynamic Light Scattering data based on multi-tau Photon Counting Histogram and variance methods. We obtained the following results and future perspectives.
Statistical analysis of Dynamic Light Scattering data
The first goal of this work consists in the analytical determination of the error bars associated to a correlation function. This problem has been analyzed by K. Schätzel in the 1990s. He provided two analytical expressions for the covariance matrix and the variance for the specific case of a Lorentzian spectrum where the correlation function is characterized by a single exponential decay. These formulas do not include the effects due to a triangular averaging and are consequently inaccurate for sampling times higher or similar than the coherence time. In this work, we analyzed these formulas and worked out two exact analytical expressions in which the effects due to the triangular averaging are corrected to all orders. By the use of extensive computer simulations and experimental test carried out on dilute dispersions of calibrated latex spheres, we have shown that the new formula for the variance works quite accurately for sampling times both higher and lower than the coherence time and can be applied well beyond the specific case of a single exponential decay auto-correlation function. We believe that these new covariance and variance formulas would turn out to be a fairly useful tool for the wide community of scientists working in the field of DLS. Nowadays, this technique is ubiquitously based on the use of multi-tau correlators, where, if not properly taken into account, the triangular averaging would introduce huge errors in the estimates of the uncertainties to be associated to the measured correlation function.
Photon Counting Histogram applied for the analysis of Dy- namic Light Scattering data
The second goal of this thesis work consists in the analysis of a second method for performing particle sizing. In this case the coherence time of the intensity fluctuations will not be recovered from a correlation, but from a series of histograms of the photon counts detected over different integration times. It represents, once normalized, the probability distribution to detect a discrete number of photon counts over a given sam- pling time. In my work we applied the Photon Counting Histogram (PCH) technique for the analysis of DLS data and we analyzed, for a monodisperse sample, the combined use of these two techniques and the advantages it gives with respect to a single one. This technique has been developed for the first time by E. Gratton for the analysis of fluorescent data. His theory works when the sampling time is much smaller than the coherence time. By using the PCH method for the analysis of DLS data, because of the raw data has been taken with the multi-tau method, we analyzed different histograms generated with different sampling times which are both higher and lower than the co- herence time. Moreover, we exploited an alternative method to perform particle sizing by recovering the hydrodynamical diameter by fitting not the histograms themselves, but the variances of the photon count distributions recovered stage by stage as a func- tion of the sampling time. We believe that both the PCH method and the variance analysis applied to DLS data may be useful because they provide a different technique to perform particle sizing, which can work independently from the auto- (or cross-) correlation functions. Both these three techniques can work in parallel and, if they provide the same result, it can be a further proof or cross-check for the correctness of the recovered hydrodynamical diameter of the considered sample
Genetic abnormalities as diagnostic and prognostic markers in B cell lymphomas: role of new molecular technologies in personalized medicine for extranodal diffuse large B cell lymphoma (EN-DLBCL) and follicular lymphoma (FL)
No full textA plethora of molecular biomarkers are available nowadays in the field of cancer research. However, it is crucial to understand when and how they can be integrated into the clinical setting, translating experimental results from bench to bedside, with the aim of improving patients’ care.
We decided to investigate the role of some of these biomarkers in two subtypes of non-Hodgkin lymphoma which still represent a challenge for both researchers and clinicians.
We started from diffuse large B cell lymphomas (DLBCLs), investigating a multicentric series of primary extranodal DLBCLs. Overall, data analysis provided strong evidence that the distribution of immunophenotypic, cytogenetic and survival characteristics is site-dependent.
We next moved to follicular lymphoma (FL). The translocation (14;18), leading to BCL2 protein overexpression, is considered the genetic hallmark of FL. We tested the incidence of BCL2 negative FLs in a series of Italian patients from the Insubric region, concluding that BCL2 rearrangement in FL is not as frequent as generally reported and that the genetic landscape of FL is more complex than previously thought.
What we learned is that even within an individual clinical entity, there is considerable heterogeneity with respect to genetic alterations, expression of commonly assayed markers and, most important, outcome. The personalized approach acknowledges this complexity and gives us tools for the continuous improvement of patients’ care
Universae Gothorum gentes Romano sese imperio dediderunt. Profili dei rapporti romano-gotici nel IV sec. d.C.
No full textThe paper analyzes the particularly problematic political, juridical-legislative and cultural situation of the period between 350 A.D. and 410 AD about, coinciding with the great migrations of the barbarian populations (especially the Gothic ones) within the borders of the Roman Empire and placing as a thematic and temporal center of gravity, the Foedus Gothicum of 382 A.D. In this context, the scientific target pursued is to identify and distinguish, if it’s possible, which legislative provisions and which literary works, produced in conjunction with the aforementioned migrations of peoples, were in causal, direct or indirect relationship, with the same relocations; which imperial constitutions were the expression of the legislative, pro-barbaric or anti-barbaric, policy of the imperial chancelleries (especially under Valente, Theodosius and his direct successors) and which coeval philosophical-literary works, on the other hand, showed the social and cultural perception of this situation and of the consequent imperial Gothic politics
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
Holistic ICT environments for effective mathematics teaching and learning
No full textTo 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
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
Structural, thermal and functional characterization of metal-organic frameworks containing poly(pyrazolates)-based ligands for carbon dioxide adsorption
No full textThe 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
A comprehensive multi-scale modeling of defective CdSe colloidal nanocrystals through advanced X-ray scattering techniques
No full textThe dissertation includes a comprehensive multi-scale modeling of defective CdSe colloidal nanocrystals through advanced X-ray scattering techniques.
Chapter 1 introduces the reader to the entire work of the Ph. D. thesis and to its main topic of research, which is focused on structural and microstructural characterization of colloidal quantum-dots. The following Chapter is dedicated to the description of conventional and unconventional characterization methods at the nanoscale, discussing their limits and potentiality in characterizing real nano-systems. Chapter 3 serves as a mathematical description of the DSE, and its implementation in the DebUsSy suite for the characterization of real ensembles of nanosized samples. Therein, the data collection and reduction procedures are also reported, together with a brief section in which the DSE to PDF approaches are compared. The need of introducing strains and defects in the complex atomistic model of CdSe nanocrystals makes it necessary to describe these defects, with a brief state of the art of their characterization methods (Chapter 4). Chapter 5 is completely dedicated to describing the computational model used for the characterization of cQDs and its use as a part of the overall data analysis strategy. The final Chapters focus on the application of the model to real systems in which its potentiality and sensitivity are tested on different materials, disclosing new size-dependent fault driven relaxation and faceting features in CdSe cQDs. An additional section presents an alternative method for the characterization of metallic NPs with larger sizes, but (much) lower stacking fault probabilities
An Italian multicentre 2-step study in patients with MANECs of the gastro-entero-pancreatic tract treated with chemotherapy.
No full textBackground. 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