10081 research outputs found
Sort by
Modelling of spectroscopic observables in molecular chromophores: static and dynamic approaches
No full textThe ability to reproduce ultrafast photo-induced processes is pivotal for advancing our understanding of molecular systems and their applications in technology. This thesis explores how these reactions unfold, focusing on the critical role of conical intersections, which provide ultrafast pathways for energy dissipation. By using cutting-edge computational methods such as CASPT2 and TD-DFT, our aim is to model the dynamics of molecules in excited states, providing insights that align with experimental results. The ability to reproduce and interpret experimental time-resolved spectra is particularly significant for understanding the transition pathways and photochemical reaction mechanisms. Throughout this research, I have focused on modelling various molecular systems, both in the gas phase and in explicit solvents, to investigate their static and dynamic behavior following photoexcitation. The overall objective has been to assign experimental spectral features to specific structural changes, electronic states, and photoreaction pathways. The aforementioned modellistic strategies have been successfully applied to interpret the photophysical behaviour of a novel molecular switch azodicarboxamide-based, supported by the simulation of the experimental UV pump / IR probe time-resolved spectrum; and to disentangle a long-standing debate concerning the de-activation mechanism of Thymidine in water following UV irradiation. Also in this case, our interpretations have been corroborated by the simulation of the UV pump / XUV probe time-resolved photoelectron spectrum to validate the quality of our simulations. Finally, the electronic structure modelling, at multi-reference 2nd-order perturbation level of theory, of the Tris(2-Phenylpyridine)Iridium transition metal complex is presented. Here, the extended number of molecular orbitals involved and the high density of close-lying excited states of different spin multiplicities pose formidable theoretical challenges aimed at obtaining a reasonable balance between accuracy and computational cost. By accurately simulating time-resolved spectra and energy pathways, these models demonstrate their robustness and predictive power, offering a reliable framework for studying ultrafast photochemical processes
Small organic molecules and proteins: a journey through bioactive compounds, receptors and biocatalysis
No full textHerein, the research activity I carried out during my PhD is reported, comprising several projects ranging from organic synthesis to protein chemistry with the common aim of studying the design, synthesis and application of bioactive compounds in health. The projects are grouped into three macro areas. The first one is focused on bioactive β-lactam-based compounds, starting from the synthesis and characterization of a small library of new ligands designed for leukocyte integrins. Then, the application of β-lactam integrin agonists in different drug delivery systems is described, starting from poly-L-lactic acid-based biomaterials loaded with an α4β1 integrin agonist, able to help wound healing in diabetic mice. Then, Targeted Drug Delivery Systems where the integrin agonist acts as the targeting unit, implemented with an imaging portion for theranostics, are depicted. A new methodology for the synthesis of bioactive N-sulfenyl β-lactam compounds starting from new N-halo azetidin-2-ones and TEMPO is also described in this section. Moving toward proteins, another macro area of this thesis is dedicated to biocatalysis, by dealing with laccases, multicopper oxidases which carry out greener oxidation reactions using oxygen as the oxidant and producing water as the only co-product. The immobilization of laccase from Trametes versicolor into PLLA scaffolds by emulsion electrospinning and the application of this heterogenous catalyst in Laccase-Mediator-System (LMS) oxidations of alcohols and amines is investigated. The effect of the introduction of visible light irradiation in LMS oxidation reactions is also described here. In the final area of the thesis, the work I carried out during six months in the group of Prof. Jesús Jiménez-Barbero at CICbioGUNE (Spain) is reported. This final chapter will merge the world of small compounds and proteins by describing the use of NMR methodologies to study ligand-protein interactions, focusing on I-branched glycans and some galectins as their lectin receptors
Reliability of WBG semiconductor devices for automotive applications
No full textPower electronics play a crucial role in modern electric vehicles, ensuring efficient energy conversion and distribution across various systems, such as motor drives, chargers, inverters, and other powertrain components. A key factor in the reliability and efficiency of these systems is the use of wide bandgap (WBG) semiconductors, such as silicon carbide (SiC) and gallium nitride (GaN). These materials possess unique properties that make them highly suitable for automotive applications, including the ability to operate at high temperature, high voltages, and high frequencies, which reduce the weight and volume of the system while improving energy conversion efficiency.
In this study, various methods for testing positive bias temperature instability (PBTI) in SiC MOSFETs were examined. Charge trapping mechanisms related to both pre-existing defects and the formation of new defects in the oxide region were identified and characterized. The effects of these defects on device characteristics were further confirmed through modeling using the Technology Computer-Aided Design (TCAD) simulator.
The reliability study of GaN HEMTs included the investigation of time-dependent gate breakdown (TDGB) and transistor behavior during short circuits. The TDGB analysis provided deeper insights into breakdown mechanisms caused by prolonged gate stress, leading to degradation and device failure. Additionally, an experimental setup was developed and presented for testing the short-circuit behavior of GaN HEMTs, as such conditions may arise due to various failures in automotive systems. GaN HEMTs were subjected to short circuits with different durations and voltage levels, enabling an assessment of their resilience and the identification of conditions under which degradation occurs.
The results of this study aim to optimize operating conditions and enhance the reliability of these devices, which is critical for the effective integration of WBG materials into automotive systems and for ensuring reliable electric vehicle operation under real-world conditions
Deep Learning for spatio-temporal analysis of anthropogenic ground deformation in the North Adriatic coasts of Italy recorded by GNSS time series
No full textDetecting and understanding ground deformation caused by human activities in areas with multiple hazards, such as natural subsidence, flooding, and earthquakes, is challenging, especially in coastal regions. This thesis addresses this challenge by using Global Navigation Satellite System (GNSS) displacement time series and advanced Deep Learning methods, including Convolutional Neural Network (CNN) and Autoencoder frameworks, to automatically identify ground deformation signals linked to both natural subsidence and anthropogenic activities. The study focuses on the North Adriatic coasts of Italy, where gas and oil storage and production have occurred between 2010 and 2023. In these areas, hydrocarbons are extracted with some changes in the volumes during the history of the sites, while gas storage involves seasonal injection (April-October) and extraction (November-March). Our approach involves simulating gas and oil reservoir behavior using a simple Mogi model and handling data gaps in the GNSS time series with the weighted principal component analysis (WPCA) technique. To generate synthetic training data for the CNN-Autoencoder model, we used 45 GNSS stations and randomly simulated gas/oil fields by varying locations (i.e., longitude and latitude), depths, and volume changes over time. The volume changes were modeled using different functions, including seasonal, exponential, multi-linear, bell-shaped, and real volume shapes corresponding to known gas storage and production sites. Since CNN-Autoencoder operates with image datasets, the Kriging interpolation method, known as Gaussian process regression, was applied to generate 2D spatial representation of daily displacements in three directions (east, north, and vertical). After calibrating the CNN-Autoencoder with these synthetic data, the model was tested on real GNSS data. Our results show the ability to detect significant subsidence in hydrocarbon production areas (-18 mm) and ground uplift in storage facilities (+2.7 mm) over the 14-year period (2010-2023), highlighting the method's effectiveness for analyzing anthropogenic deformation patterns in dynamic coastal environments
Homo- and hetero-metallic carbonyl clusters based on group 8 transition metals
No full textThis PhD thesis presents an investigation of the synthesis, characterization and catalytic properties of homo- and hetero-metallic carbonyl clusters based on Group 8 metals (Fe, Ru, Os). Comprehensive characterization of the synthesized new compounds were achieved through single crystal X-ray diffraction (SC-XRD), FT-IR, multi-nuclear NMR and ESI-MS spectroscopies. The experimental results were also complemented by computational investigations employing DFT studies.
The first part of this Thesis focuses on the reactions involving the homo-metallic precursor [HRu3(CO)11]– (1) and complexes of other transition metals (Ir, Cu, Ag, Au), leading to a range of novel hetero-metallic clusters. These Ru-M clusters were tested as catalyst precursors in the transfer hydrogenation reaction of 4-fluoroacetophenone, and compound [H2Ru3Ir(CO)12]– (2) proved also to be active in the hydrogenation of trans-cynnamaldehyde. The reaction between [HRu4(CO)12]3– (12) and Au(PPh3)Cl, under different experimental conditions, yielded new peraurated Ru hydride carbonyl clusters; detailed spectroscopic and computational analyses confirmed their structures, including the identification of weak aurophilic interactions. Furthermore, the redox chemistry of the iron carbide car-bonyl cluster [Fe6C(CO)15]4– (23) was examined. Its chemical oxidation processes were investigated using various oxidants and trapping agents; moreover, electrochemical, IR spectro-electrochemical and DFT studies on 23 have been conducted, in order to unravel the experimental conditions for the functionalization of the Fe6C cage without fragmentation. The SC-XRD molecular structures of novel tri-anionic species of the type [Fe6C(CO)14(SR)]3– are reported. The chirality of the two enantiomers of [Fe6C(CO)14(Cys)]3– (33), derived from reactions with enantiopure L- and D-Cysteine, was assessed through vibrational circular dichroism (VCD) studies, supported by computational simulations. The synthesis and characterization of novel chiral Os3Rh clusters with chiral diphosphine ligands of Walphos family are reported
New solutions for historical masonries affected by rising damp: from monitoring techniques to bio-based treatments against salt crystallization
No full textThe preservation of architectural heritage is significantly challenged by the presence of moisture in masonry, which plays a critical role in deterioration processes affecting historical architecture, especially salt weathering. Despite the recognition of rising damp as a pervasive issue, current solutions for its effective removal remain insufficient, largely due to challenges in accurately quantifying moisture levels in construction materials. This research aims to tackle these intertwined challenges through two key approaches: advancing moisture measurement methodologies and exploring innovative strategies to mitigate salt-induced deterioration. A new sensor system was rigorously tested in both controlled laboratory environments and real-world settings, enabling continuous and remote monitoring of moisture dynamics. Additionally, a comprehensive monitoring campaign has been carried out to assess the health state of the historic Church of Santa Croce in Ravenna, utilizing minimally invasive techniques that account for the complexities inherent in ancient masonry. Furthermore, the study investigates the potential of using chitosan, a biopolymer sourced from crustacean shells, in conjunction with diammonium phosphate (DAP), to mitigate the detrimental effects of salt damage. By harnessing the unique properties of these materials, this research proposes an innovative approach to enhance the longevity and resilience of historical structures against salt crystallization. Through the integration of advanced moisture measurement and targeted damage mitigation strategies, this work aspires to provide meaningful contributions to the field of conservation science, promoting the effective safeguarding of the invaluable architectural heritage
Decision-support systems for environmental- and social-driven planning and control of agri-food supply chain ecosystems
No full textThe agri-food supply chain (AFSC) plays a fundamental role in global food security but also contributes significantly to environmental degradation and socio-economic disparities. Ensuring sustainability in AFSCs requires integrated decision-support systems (DSS) that address environmental and social challenges while improving operational efficiency. However, existing decision-support approaches often fail to incorporate multi-dimensional trade-offs between environmental impact, economic feasibility, and social equity.
This dissertation develops a comprehensive, data-driven framework to enhance transparency, sustainability, and social justice within the AFSC. Through decision-support systems, mathematical modeling, optimization techniques, and digital twin technology, this research addresses four key challenges: advancing environmental sustainability, fostering social and economic justice, supporting SC decision-making, and enhancing consumer awareness.
By integrating descriptive, prescriptive, and predictive approaches, this thesis bridges gaps in existing research, particularly the lack of consumer-focused sustainability tools and the need for unified models linking social and environmental concerns. A central innovation is a Digital Twin model, which provides real-time insights into the environmental and social impacts of food production, distribution, and consumption. This tool supports policymakers and stakeholders for a top-down improvement while equipping consumers with clear, data-driven insights into product sustainability, promoting a bottom-up shift toward responsible consumption.
Findings demonstrate that integrated DSS and DT technologies enable more sustainable food production, optimize logistics, and provide transparency for stakeholders. This research contributes to a holistic, scalable framework for sustainable AFSC planning and control by combining mathematical modeling, optimization techniques, and digital tools.
This work provides practical insights for policymakers, industry practitioners, and researchers, supporting the transition toward a more resilient, equitable, and environmentally responsible food system.Le Filiere Agroalimentari (FA) svolgono un ruolo fondamentale nella sicurezza alimentare globale, ma contribuiscono in modo significativo anche al degrado ambientale e alle disuguaglianze socio-economiche. Garantire la sostenibilità nelle FA richiede Sistemi di Supporto alle Decisioni (SSD) integrati, capaci di affrontare le sfide ambientali e sociali, migliorando al contempo l'efficienza operativa. Tuttavia, gli approcci esistenti spesso affrontano queste dimensioni separatamente, limitando l’efficacia delle strategie per la sostenibilità.
Questa tesi sviluppa un quadro metodologico basato sui dati per migliorare trasparenza, sostenibilità e giustizia sociale nelle FA. Attraverso SSD, modelli matematici, tecniche di ottimizzazione e tecnologie di Digital Twin (DT), la ricerca proposta affronta quattro sfide chiave: promuovere la sostenibilità ambientale, favorire la giustizia sociale ed economica, supportare il processo decisionale lungo la filiera e aumentare la consapevolezza dei consumatori.
Integrando approcci descrittivi, prescrittivi e predittivi, questa tesi colma alcune lacune della letteratura, in particolare la scarsa disponibilità di strumenti per la sostenibilità rivolti ai consumatori e la scarsa integrazione tra dimensioni sociali e ambientali. Un'innovazione chiave è lo strumento del Digital Twin, che fornisce analisi in tempo reale sugli impatti della produzione e distribuzione alimentare, migliorando la sostenibilità e la trasparenza lungo la filiera. I risultati dimostrano che l’integrazione tra SSD e DT consente una gestione più sostenibile della FA, ottimizzando logistica e risorse, migliorando la tracciabilità e consentendo decisioni consapevoli. Questa ricerca propone un framework scalabile e integrato per la pianificazione e il controllo sostenibile delle FA, offrendo strumenti pratici per stakeholder e ricercatori.
In definitiva, questo lavoro fornisce soluzioni data-driven per una filiera agroalimentare più resiliente, equa e responsabile, allineata alle esigenze di sostenibilità e trasparenza del mercato globale, offrendo anche spunti pratici a supporto del decision-making di policy-maker e operatori del settore
Investigating the nutritional value of food from sustainable sources: insights on the bioaccessibility of key nutrients and the biological properties of food-derived compounds
No full textThe 21st century faces significant nutritional challenges as global population growth and current food systems deplete planetary resources. While environmental sustainability has become fundamental throughout the agri-food chain, sustainable food production must also ensure high nutritional value. Since food matrix modifications can influence nutrient bioaccessibility—a limiting factor for nutrient absorption and physiological effects—evaluating variations in this parameter is essential. In the first section, we evaluated protein and n-3 LC-PUFA bioaccessibility in sustainably farmed and processed fish products, confirming preserved nutritional value. However, our assessment of n-3 LC-PUFA bioaccessibility in supplements revealed that Calanus finmarchicus-based products cannot sustainably substitute traditional fatty acid sources like fish oil. Digestion not only makes food components bioaccessible but can also alter nutrients' molecular structure, creating compounds with different or enhanced biological activity. These digestion-derived compounds impact intestinal barrier function, whose dysregulation links to many non-communicable diseases. In the second and third sections, we investigated digestion-derived bioactive compounds' biological effects using an in vitro intestinal barrier model (Caco-2 and HT29-MTX-E12 cell lines). We focused on β-casomorphin-7 (BCM-7) from dairy products and Spirulina-derived compounds (phycocyanin, pheophytin a, and pheophorbide a). Our findings suggest that physiological concentrations of BCM-7 do not negatively affect the intestinal barrier, while Spirulina pigments demonstrate anti-inflammatory effects. This thesis examines crucial gastrointestinal system events, bridging the gap between external food environment and internal human health processes
Implicating hearts and minds: transcultural memory in world literatures of the global war on terror
No full textThis thesis scrutinizes the potential of postcolonial World Literatures to commemorate the US-led Global War on Terror through the lens of the implicated subject. In contrast to a first wave of post-9/11 cultural responses viewed as nationally insular and complicit with US imperial amnesia, this dissertation locates itself firmly within a second-wave of imaginative and scholarly discourse (2008-present) grappling with the injustices of the War on Terror and linking them to other legacies of colonial-imperial domination. While partaking in this strand of critical revisionism, I also challenge prevailing frameworks of ‘writing back’ that recover the memorial connections between groups conflated under the label of ‘terrorists’—Muslims and other nonwhite communities—exclusively through a lens of victim trauma and reparation. I argue that while the intervictim model of transcultural remembrance provides a crucial corrective to the post-9/11 memory regime, it often fails to account for the gray zones of imperialist violence sustained by networks of US economic, academic, and mediatic institutions. Rather than only reading for resistance from below, I compare figures and forms of racial implication in the artworks of Babak Jalali, Sinan Antoon, Yuri Herrera, and Coco Fusco in order to propose a supplementary framework for reading post-9/11 cultural production
Primary dilated cardiomyopathy with onset in childhood: analysis of clinical-instrumental characteristics, genetic variants and their prognostic impact in patients followed at a specialist outpatient clinic in a tertiary care center.
No full textLe cardiomiopatie pediatriche sono malattie rare ma gravate da un’alta mortalità, con un’incidenza di 1,5 bambini su 100.000/anno. La cardiomiopatia dilatativa (CMD) rappresenta circa il 50% dei casi, spesso è individuabile una base genetica. Sebbene i test genetici non siano ancora eseguiti in modo sistematico in età pediatrica, la loro utilità per la gestione della malattia e la possibilità di predirne la prognosi sta emergendo come è successo per i pazienti adulti. Questo studio retrospettivo ha analizzato 121 pazienti pediatrici con cardiomiopatia dilatativa (CMD), con un follow-up medio di 10 anni, seguiti presso l’ambulatorio cardiomiopatie dell’unità operativa di cardiologia e cardiochirurgia pediatrica dell’ospedale Sant’Orsola dal 2000 ad oggi. L’età media alla diagnosi era di 6,11 anni, e il 44% dei pazienti erano femmine. L’analisi genetica ha identificato mutazioni patologiche in 43 pazienti (35,5%), mentre in molti altri la diagnosi genetica non ha prodotto risultati significativi. I pazienti con eziologia metabolica o neuromuscolare hanno mostrato un maggiore rischio di mortalità. Tra i 62 pazienti che hanno sviluppato eventi avversi, 27 hanno ricevuto un trapianto cardiaco, 25 sono deceduti e 25 hanno sviluppato aritmie. Variabili cliniche come una bassa frazione di eiezione, dilatazione ventricolare sinistra e alterazioni elettrocardiografiche sono risultate predittive di un outcome avverso. La presenza di non compattazione del ventricolo sinistro (LVNC) è emersa come un fattore non associato ad outcome avverso, così come già dimostrato per i pazienti adulti. La diagnosi genetica non ha influenzato significativamente gli outcome clinici, ma l’alta mortalità associata alle cardiomiopatie metaboliche suggerisce una potenziale utilità in questa tipologia di pazienti. Lo studio evidenzia la necessità di implementare i protocolli di analisi genetica nei pazienti pediatrici con CMD.Pediatric cardiomyopathies are rare diseases characterized by high mortality rates, with an incidence of 1.5 children per 100,000 per year. Dilated cardiomyopathy (DCM) accounts for approximately 50% of cases, often with an identifiable genetic basis. Although genetic testing is not yet systematically performed in the pediatric population, its utility for disease management and the potential to predict prognosis is emerging, similar to what has been observed in adult patients. This retrospective study analyzed 121 pediatric patients with dilated cardiomyopathy (DCM), with an average follow-up of 10 years, monitored at the cardiomyopathy outpatient clinic of the pediatric cardiology and cardiac surgery unit at Sant'Orsola Hospital from 2000 to present. The mean age at diagnosis was 6.11 years, and 44% of the patients were female. Genetic analysis identified pathogenic mutations in 43 patients (35.5%), while many others had non-significant genetic diagnostic results. Patients with metabolic or neuromuscular etiology exhibited a higher risk of mortality. Among the 62 patients who developed adverse events, 27 underwent heart transplantation, 25 died, and 25 developed arrhythmias. Clinical variables such as low ejection fraction, left ventricular dilation, and electrocardiographic abnormalities were found to be predictive of adverse outcomes. The presence of left ventricular non-compaction (LVNC) emerged as a factor not associated with adverse outcomes, as previously demonstrated in adult patients. Genetic diagnosis did not significantly influence clinical outcomes, but the high mortality associated with metabolic cardiomyopathies suggests potential utility in this patient population. The study highlights the need to implement genetic analysis protocols in pediatric patients with DCM