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Accesso Sicuro a Servizi Context-Aware nella Smart City
No full textThe evolution of the Web to Web 2.0 before and after the Web of Things, has resulted in a transformation of what over the years has been the role of the user. Thanks to this socio-technological evolution, we have seen the birth of the first smart cities, which will be pervaded by services produced and delivered tailored to their citizens.
The thesis addresses the key issues that affect the interaction between users and context-aware services within the smart city, with particular attention to the generation, discovery and access control of these services
Novel Approaches to Photoactive Nanostructured Materials for Efficient Solar Cells
No full textCon l'attività di ricerca, riportata in questa tesi di Dottorato, ho fornito, alle questioni concernenti il fotovoltaico, i seguenti contributi:
1.Ricerca e sviluppo di un semplice metodo di sintesi di semiconduttori nanostrutturati, con una morfologia particolarmente adatta all'assorbimento efficiente di radiazione per le celle solari. Inoltre, è stato intrapreso lo studio di innovative geometrie e le relative peculiari interazioni con la luce.
2.Analisi e confronto dimetodi di deposizione fisici e chimici per la sintesi di film sottili di Cu2O, per applicazioni nel fotovoltaico. Poichè l'efficienza delle celle solari, a base di Cu2O, non hanno , ancora superato il 6%, parte di questo lavoro è stata dedicata al miglioramento delle proprietà fisiche del materiale per mezzo di doping
Multi-sensor Data Fusion for Robotics Applications
No full textThanks to faster and better integrated processing units, as well as increasingly miniaturized and precise sensors, Robotics is experiencing a period of significant development.
New technology is making robots increasingly more autonomous. Data from different sensors can be fused and processed in real time by on-board processing units in order to make the robot perform either more or less complicated tasks.
Unmanned Ground Vehicles (UGV) and Unmanned Aerial Vehicles (UAV) equipped with sensors and microprocessors/microcontrollers can be remotely piloted. They can also move autonomously with the help of different navigation and localization methods.
Power electronics is contributing to a transformation in many fields such as robotics, automotive and consumer devices.
Some new applications of power electronics are discussed in the first chapter of this thesis. One of these describes how new power electronics devices allow the use of distributed instead of centralized control in industrial robotics.
Multi-sensor data fusion theory is presented in the second chapter; the Kalman Filter and Particle Filter are described.
Inertial sensors and magnetometers are introduced in the third chapter with the description of a calibration procedure for each sensor.
Two new methods of multi-sensor data fusion, based on low-cost Micro Electro-Mechanical Systems (MEMS) Inertial Sensors, to estimate joint angles of industrial manipulators are described in the fourth chapter. The results of two experimental tests are also presented to evaluate and to compare the performances of the two methods.
A method to estimate the attitude and heading of an UAV is described in the fifth chapter. In order to check the performance of the developed method, at the end of the fifth chapter, a comparison test with a high accuracy system is presented.
A localization algorithm for a wheeled UGV equipped with a GPS and an inertial platform is described in the sixth chapter. Simulation tests and experimental results are also presented at the end of the sixth chapter
Psychometrics in Major Depression and Alzheimer s disease
No full textPsychometrics is the science of psychological measurement and is concerned with the objective measurement of skills and knowledge, abilities, attitudes, personality traits, and educational achievement. Efficacy trials with antidepressant drugs often fail to demonstrate beneficial effects, even though efficacious treatments are investigated, due, among other factors, to the lack of sensitivity of psychometric tools.
Affective disorders and particularly major depressive disorders (MDD) have been recently identified as new risk factors for the development of mild cognitive impairment and Alzheimer s disease (AD).
According to this clinical continuum between depression, MCI and AD new strategies of neuropsychological assessments should be explored by using multiple psychometric tools able to detect both affective and cognitive symptoms from depression and MCI to early AD.
Aim of the present Doctorate Thesis is to discuss recent evidence on the role of psychometric tools in the diagnosis of MDD and AD and in the evaluation of pharmacological treatment, focusing on a new combination of psychometric tools useful to detect early cognitive deficits both in MDD patients and MCI patients with an high risk to convert into AD.
The results presented in the PhD Thesis have been published in two articles on peer-reviewed journals, whereas a third study has been recently submitted for publication.
My first study demonstrated the efficacy of omega-3 in depressed patients and was based on psychometric data obtained with Hamilton Depression Rating Scale (HDRS) in published clinical studies. Omega-3 were also effective on bipolar disorder, although the evidence was weakened by the exclusion of three studies conducted on patients with MDD or on patients with depressive symptoms in which a lack of rigor in patients selection may lead to the inclusion of both normal emotional states and subthreshold depressed subjects, eventually affecting the results.
The study, in addition, highlights a number of methodological criticisms that mainly concern the inclusion criteria that should be more rigid and based on the score to psychometric tests rather than solely on clinical diagnosis. Psychometric instruments, in fact, represent an essential tool not only for a better diagnostic or for evaluating the efficacy of a treatment, but also for use inclusion criteria more rigid in order to improve the methodology in efficacy studies.
In the second study we critically reviewed the current literature on biological and neuropsychological markers in amnestic MCI patients who are at high risk to develop AD. A major conclusion of this study was that it is possible to identify a combination of neuropsychological tools (MMSE, MoCA, Rey s Test, FAB) and validated biological markers essential for an early diagnosis of AD and also for monitoring the response to disease modifying therapies in amnestic MCI patients who are at high risk to develop AD.
In the third study presented in this doctorate thesis we have adopted a new strategy of psychometric evaluation combining standard psychometric tools validated for the assessment of affective symptoms in MDD patients (HDRS and BDI-II) with neuropsychological tools such as MMSE, MoCA, FAB, Rey s 15 Words Test developed to detect cognitive deficits in mild cognitive impairment or in early AD.
The main finding of our observational study is that both SSRIs and SNRIs can improve cognitive symptoms independently from their clinical efficacy on affective symptoms.
As a neurobiological and clinical continuum exists between major depression, MCI, and dementia, we believe that our strategy of neuropsychological assessments can be applied to a wide range of patients from MDD to MCI/AD. This neuropsychological battery might represent a new tool to detect in future clinical studies affective symptoms and early cognitive deficits not only in MDD patients, but also in MCI patients with an high risk to convert into AD
Involvement of metabotropic glutamate receptor subtype mGlu5 in the pathophysiology of Fragile X Syndrome.
No full textFragile X Syndrome (FXS) is the most common inherited form of intellectual disability and autism. FXS is caused by a mutation in the fragile X mental retardation 1 (Fmr1) gene which leads to the lack of the encoded FMRP protein. FMRP is an RNA binding protein involved in protein synthesis regulation at synapses. Many evidences suggest a central role of the Group-I metabotropic glutamate receptor subtype 5 (mGluR5) in the FXS pathophysiology. In particular, an exaggerated signaling response following mGluR5 activation may underlie synaptic dysfunction in this disorder. Although much work has focused on the dysregulation of synaptic protein synthesis as a consequence of this enhanced mGluR5 signaling, it becomes clear that in FXS there is also an altered balance of mGluR5 association with Homer scaffolding proteins, which are postsynaptic density (PSD) partners of mGluR5. Although an extensive literature describes the mGluR5/Homer association, very little is known about the consequences of the disruption of this interaction in the FXS context. Therefore, the goal of my thesis was to study the consequences of mGluR5/Homer crosstalk disruption in the Fmr1 knockout (KO) mouse model of FXS in term of properties and functions of mGluR5, such as expression during development, surface expression and axonal/dendritic targeting, agonist-induced internalization, surface dynamics and mGluR5-mediated modulation of NMDA receptor (NMDAR) currents.
In a first set of experiments we investigated the mGluR5 surface expression in cultured hippocampal neurons from WT and Fmr1 KO mice by using immunofluorescence techniques and biotinylation assay. We found that mGluR5 was more expressed on the neuronal surface and was differently distributed in dendrites and axons of Fmr1 KO cultured neurons. We then hypothesized that these alterations were a direct consequence of the mGluR5/Homer crosstalk disruption. We demonstrated that these altered expression and targeting of mGluR5 were critically dependent on mGluR5/Homer crosstalk disruption. We also observed that mGluR5 did not undergo internalization upon sustained mGluR5 activation with DHPG in Fmr1 KO neurons. This latter phenotype, however, was not dependent on the disruption of the mGluR5/Homer crosstalk. Altogether, these results demonstrate that mGluR5/Homer crosstalk disruption contributes to the pathophysiology of FXS altering expression and targeting of mGluR5 on the surface of Fmr1 KO neurons.
In the second part of my study we investigated the consequences of the disrupted mGluR5/Homer crosstalk for the mGluR5 surface dynamics, and consequently for NMDAR function in Fmr1 KO neurons. Using a combination of live-cell imaging and single-molecule tracking, we found that mGluR5/Homer crosstalk disruption specifically increased the mGluR5 lateral diffusion at the synapse of cultured Fmr1 KO hippocampal neurons. The higher mGluR5 mobility resulted in an increased probability of transient physical interaction with NMDAR in the PSD of Fmr1 KO. This interaction altered the mGluR5-mediated modulation of NMDAR currents as evidenced by the two following changes. First, using patch-clamp recordings from CA1 pyramidal neurons, we found that NMDAR-mediated excitatory postsynaptic currents (NMDAR-EPSCs) evoked by Schaffer collateral stimulation showed lower amplitudes in Fmr1 KO neurons. Second, the postsynaptic expression of mGluR5 mediated long term depression (LTD) of NMDAR-EPSCs was reduced in Fmr1 KO neurons. Finally, we demonstrated that these defects in NMDA currents were strongly dependent on the mGluR5/Homer crosstalk disruption and altered mGluR5 dynamics.
Our results show that mGluR5/Homer disruption contributes to the mGluR5 dysregulation in Fmr1 KO neurons. This study might have implication for the treatment of mGluR5 synaptic dysfunctions in FXS by targeting mGluR5/Homer interaction and provide new suggestions to correct the defective signaling underlying cognitive impairment and autism
Muon Portal project: Tracks reconstruction, automated object recognition and visualization techniques for muon tomography data analysis
No full textThe present Ph.D. thesis is contextualized within the Muon Portal project, a project dedicated to the creation of a tomograph for the control and scanning of containers at the border in order to reveal smuggled fissile material by means of the cosmic muons scattering. This work aims to extend and consolidate the research in the field of muon tomography in the context of applied physics. The main purpose of the thesis is to investigate new techniques for reconstruction of muon tracks within the detector and new approaches to the analysis of data from muon tomography for the automatic objects recognition and the 3D visualization, thus making possi- ble the realization of a tomography of the entire container. The research work was divided into different phases, described in this thesis document: from a prelimi- nary speculative study of the state of the art on the tracking issue and on the tracks reconstruction algorithms, to the study on the Muon Portal detector performance in the case of particle tracking at low and high multiplicity. A substantial part of the work was devoted to the study of different image reconstruction techniques based on the POCA algorithm (Point of Closest Approach) and the iterative EM-LM algorithm (Expectation-Maximization). In addition, more advanced methods for the tracks reconstruction and visualization, such as data-mining techniques and clustering algorithms have been the subject of the research and development ac- tivity which has culminated in the development of an unsupervised multiphase clustering algorithm (modified-Friends-of-Friends) for the muon tomography data analysis
Efficient electro-thermal analysys and optimization of induction heating devices
No full textThe use of eddy current devices is very common in several areas of Electrical Engineering such as non-destructive testing, electrical machines and induction heating. The latter, particularly, in the last decades, was widely applied to several fields, including heavy industry, chemical industry, electro-medical devices, domestic appliances. In fact this technique has a number of intrinsic advantages: such as a very quick response and a good efficiency. Induction heating also allows heating very locally, the heating speeds are extremely high because of the high power density and the heating process can be regulated precisely.
The aim of this work was the development of numerical methods for analysis and design of induction devices. The analysis of these devices is usually tackled by means of numerical techniques and can be often very hard due to the necessity to deal with a three-dimensional electromagnetic field problem that extends to infinity. In the case of an induction heating devices the electromagnetic analysis is coupled with a non linear thermal one. The proposed approach minimizes the computational cost of analysis with no loss of accuracy.
At first, a reduction of the number of numerical unknowns was obtained restrincting the FEM domain to conductors region by means of the new FEM-SDBCI method (Singular Dirichlet Boundary Condition Iteration), explained in Chapter I. The method is described for three-dimensional eddy current problems in which the electrical field is used as unknown in a mesh of edge elements. This method alleviates the major drawback of FEM-DBCI, that is, the insertion of some element layers between the integration and truncation surfaces and consequently allows the use of a common mesh for thermal analysis in coupled problems. The procedure couples a differential equation for the interior problem in terms of the electric field with an integral equation for the exterior one, which expresses the Dirichlet condition on the truncation boundary; note that, without the insertion of element layers between inner domain and truncation boundary, the integral equation becomes singular. The global algebraic system is efficiently solved in an iterative way. The use of an efficient mesh generator based on an artificial neural network which allows good-accuracy solutions with a lower computational effort is also described.
In Chapter II a strategy to perform FEM solutions of coupled electromagnetic-thermal problems is described. In this kind of problems, the electromagnetic one needs the large part of computing time; it is possible to limit the number of electromagnetic solutions by means of a control on the variations of temperature-dependent electric parameters. The solution of the eddy current problem leads to the calculation of power density in each finite element. Starting from this power density, a transient thermal analysis employing nodal tetrahedral finite elements of a given order is carried out. The thermal conductivity and the specific heat are assumed to be temperature-dependent. To solve the transient non linear problem, a Crank-Nicolson scheme was implemented.
In order to perform the design of induction devices the proposed analysis method was used as evaluation block into an optimization strategy particularly suitable to tackle this kind of problems, the PSALHE-EA algorithm, described in Chapter III. The PSALHE-EA has some new features that permit to considerably reduce the overall optimization time allowing to make full use of parallelization. Moreover, it is able to identify multiple optima by locating global as well as local optima; this aspect could be advantageous in industrial design, because the designer may want to see several design alternatives. The tests performed show that PSALHE-EA is a very efficient hybrid optimization method and in this work it was successfully applied to the design of an induction heater for conductor pieces
L'edizione di due trattati di mascalcia in volgare siciliano del ms. 2934 della Biblioteca Riccardiana di Firenze
No full textIl lavoro dal titolo L edizione dei due trattati di mascalcia in volgare siciliano del codice 2934 della Biblioteca Riccardiana di Firenze (XV secolo) si configura, da un punto di vista generale, come un contributo alla ricostruzione di un segmento di storia della medicina veterinaria; nella prospettiva degli studi sul volgare siciliano, consente l accesso a una tipologia di testi che, dopo i contributi di De Gregorio (1904), De Gregorio (1905), e le tesi di laurea di La Rosa (2000) e Di Costa (2001), è stata di fatto negletta.
La tesi si articola in due parti: nella prima parte introduttiva il candidato, dopo aver accennato ai preliminari informativi sulle due mascalcie editate, fornisce una breve panoramica sui testi pratico scientifici in volgare siciliano, documentando gli ambiti di produzione e fruizione, e analizzando il ruolo di notevole importanza che ricoprono i trattati di mascalcia all interno di questa tipologia di testi, come testimonia anche la loro presenza in biblioteche private.
In funzione dell edizione dei due trattati del ms. Riccardiano, l approccio esperito è stato quello di evidenziare i loro rapporti con la tradizione latina (e, indirettamente, anche greca) e con altri trattati di mascalcia in volgare siciliano, presi in considerazione per la prima volta.
L aggiornamento della bibliografia e un indagine accurata sui modelli ha evidenziato la natura singolare e composita del primo trattato, frutto di una contaminatio tra fonti eterogenee, quali Giordano Ruffo, la traduzione di Bartolomeo da Messina del De curatione equorum ad Bassum di Ierocle, con una distribuzione all interno del testo corrispondente a tre nuclei o blocchi: iniziale (Ruffo), centrale (Bartolomeo da Messina), finale (Ruffo).
Il confronto sistematico tra il secondo trattato e il testo di Ruffo ha confermato che siamo di fronte a un volgarizzamento dell opera del nobile calabrese della corte federiciana.
A conclusione di questa prima parte introduttiva si sono esaminati i modi della traduzione dell anonimo volgarizzatore e i caratteri linguistici dei due trattati di mascalcia. Sulla scorta di questa indagine possiamo affermare che non si tratta certamente di una traduzione passiva, che si limita a ricodificare il testo originario nella lingua d arrivo. La seconda parte della tesi è dedicata all edizione dei testi. Il testo critico è corredato da un apparato suddiviso in due fasce.
Le edizioni dei due volgarizzamenti sono seguite da Note ai testi con notizie sul codice, la sua descrizione codicologica, gli studi sullo stesso, la qualità della copia, la consapevolezza culturale del volgarizzatore/copista e la presentazione dei criteri editoriali adottati
Anti-inflammatory and antioxidant activities of Nrf2/HO-1 activators: in vitro studies in microglia and retinal cells
No full textInflammation and oxidative stress play essential roles during the progression and resolution of disease states. It is now being recognized that persistent inflammation and oxidative stress underlie several chronic diseases of Western countries. This is relevant in the ageing population, where neurodegenerative diseases and diabetes, among others, are pathologies that require pharmacological interventions targeting multiple pathways involved in these diseases. Microglia cells, the macrophages of the brain, work under normal conditions to protect neurons from infectious agents and by removing dead cells to promote tissue repair. Similarly, retinal pigmented epithelial cells support the eye by protecting photoreceptors and mediating nutrient uptake for retinal tissue. Because of their anatomical position, both cell types participate in the pathophysiology of neurodegenerative diseases and retinal diabetes complications. A highly relevant cellular response to stress is mediated by the nuclear factor (erythroid-derived 2)-like 2 (Nrf2), a redox sensitive protein that promotes the up-regulation of cytoprotective enzymes. Among these genes is heme oxygenase-1 (HO-1), which converts heme into iron, carbon monoxide and biliverdin, subsequently reduced to bilirubin by biliverdin reductase. These products exhibit anti-inflammatory and antioxidant actions in models of disease characterized by redox stress and inflammation and lack of HO-1 exacerbates damage in experimental animal models and two human cases reported in the literature. The Nrf2/HO-1 axis is amenable to pharmacological manipulation and molecules that target these pathways are of high interest for the discovery of therapeutic approaches to counteract neuroinflammation and retinal diseases. The work presented herein focuses on characterizing anti-inflammatory and antioxidant activities of Nrf2/HO-1 activators. In the first instance I identified effective Nrf2/HO-1 inducers that modulate the inflammatory response in BV2 murine microglia cells. I searched the literature and selected 56 compounds that activate Nrf2 or HO-1 and analyzed them for HO-1 induction and cytotoxicity in vitro. Approximately 20 compounds increased HO-1 at concentrations of 5 to 20 µM, with carnosol, curcumin, cobalt protoporphyrin-IX and dimethyl fumarate (DMF) exhibiting the best induction/low cytotoxicity profile. HO-1 up-regulation by some compounds resulted in increased bilirubin which correlated with the potency of the inducers to reduce nitrite production after challenge with interferon-ã (INF-ã) or lipopolysaccharide (LPS). The compounds strongly down-regulated inflammation (TNF-á, PGE2 and nitrite) in cells stimulated with INF-ã and LPS; silencing HO-1 or Nrf2 with shRNA partially reversed this effect. I then chose the Nrf2 inducers DMF and carnosol and investigated their effect on antioxidant pathways, oxygen consumption and wound healing in human retinal pigment epithelial cells (ARPE-19) grown in medium containing normal (NG) or high (HG) glucose to mimic hyperglycemia. I found that Nrf2 activation and heme oxygenase increased in ARPE cells treated with DMF or carnosol irrespective of glucose levels. However, in HG retinal cells were more sensitive to regulators of glutathione synthesis and produced lower reactive oxygen species. Culture in HG decreased respiration, ATP levels and damaged mitochondria; treatment with DMF or carnosol did not restore oxygen consumption. Using the scratch assay in vitro I observed that wound closure was faster in HG than NG cells and was accelerated by carnosol. An inhibitor of heme oxygenase reversed this effect, supporting a pro-healing role of HO-1. In summary, Nrf2/HO-1 activators modulate microglia inflammation and exert pharmacological activities in retinal cells cultured under normal or hyperglycemic conditions. Thus, promising chemical scaffolds are identified for the synthesis of potent new derivatives to counteract neuroinflammation and retinal diseases
Processi innovativi per la futura generazione di MOSFETs ad alta efficienza energetica in Carburo di Silicio
No full textIn the modern society, the reduction of the energy consumption through its efficient use has become the main task of power electronics. In this context, Silicon Carbide (SiC) exhibits interesting electrical and physical properties which can satisfy the continuous demands of improved energy efficiency, overcoming the limitations of Silicon. Today several SiC technologies have reached the industrial maturity. In this thesis, different aspects and challenges related to the fabrication of 4H-SiC MOSFETs (which are among the most appealing devices due to their driving simplicity) have been treated. Indeed, in spite of remarkable and recent progress, still several scientific aspects need to be dealt to reduce the energy dissipation and to overcome the issues still open. In particular, the aim of this thesis has been to clarify the mechanisms ruling the transport properties at the interfaces metal/SiC and SiO2/SiC. Special focus was given to the study of the mechanisms limiting the channel mobility in lateral MOSFETs. All the achievements and progresses obtained have been integrated in a power MOSFET device, whose behaviour has corroborated the great potential of the material