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Morphological analysis of lesions in post-stroke patients with hemiparetic motor disorder : a correlational study
No full textTra le conseguenze cliniche più comuni e invalidanti a seguito di un ictus i disturbi di natura motoria occupano una posizione di rilievo. La frequente condizione di emiparesi post stroke, tipicamente associata a compromissioni del tratto corticospinale (CST), può essere causata da incidenti a svariate strutture cerebrali coinvolte nella motricità. Studi di lesione condotti sul modello animale dimostrano, ad esempio, come un danno all’area della mano di M1, sia responsabile di flaccidità e ipotonia dell’arto controlaterale (Fogassi et al., 2001). Tuttavia, il grado di recupero delle abilità motorie dopo un ictus dipende grandemente da un’opportuna plasticità cerebrale e un’attivazione anche di svariate ulteriori regioni risparmiate. Conoscere i modelli neurali e procedere tramite un’identificazione delle regioni cerebrali danneggiate e di quelle conservate a seguito di uno stroke, può consentire di ottimizzare ed individualizzare i programmi terapeutici. A partire da tale ipotesi, è stato in questa sede condotto uno studio pilota di natura correlazionale su un campione di 10 pazienti adulti post ictus con emiparesi dell’arto superiore, in fase subacuta e cronica. L’analisi di sequenze RM ha permesso di valutare l’entità delle lesioni e il grado di perfusione cerebrale di ciascun paziente, mentre la performance motoria è stata misurata tramite scale cliniche, quali: Box and Block Test (BBT), Motricity Index (MI), modified Rankin Scale (mRS) e modified Ashworth Scale (mAS). La primaria analisi neuroradiologica qualitativa è stata integrata con una segmentazione e stima quantitativa della gravità del danno cerebrale, per mezzo di svariati metodi di indagine. È stata evidenziata un’elevata variabilità delle aree corticali compromesse all’interno del campione, mentre risultano più frequenti e coerenti le disconnessioni di specifici fasci di sostanza bianca. È emerso, inoltre, come un maggior risparmio di alcuni tratti di fibre ipsilesionali (IL), fosse positivamente associato a punteggi più elevati alla scala MI. Correlazioni positive sono state riscontrate anche tra il grado di perfusione nelle ROI selezionate e lo stato funzionale dei pazienti, misurato con le tre scale MI, mAS e mRS. Infine, il numero di voxel lesionati nell’emisfero IL ha rivelato un’attesa relazione negativa con il punteggio al Motricity Index. Questa scala, comunemente utilizzata al fine di misurare la forza muscolare globale in condizioni di emiparesi post-stroke, ha mostrato una più frequente e forte correlazione con il dato morfologico rispetto al test Box and Block: una discrepanza verosimilmente associata alla ridotta numerosità campionaria. Complessivamente, con la presente ricerca si propone il ricorso a un approccio multivariato e integrato di valutazione della funzionalità motoria, tramite il ricorso a scale cliniche differenti. L’analisi approfondita del quadro patologico del paziente può essere pertanto utile, non solo a predirne la performance, ma anche a garantire la migliore progettazione di interventi riabilitativi. Among the most common and disabling clinical consequences following a stroke, motor disorders hold a prominent position. The frequent condition of post-stroke hemiparesis, typically associated with impairments of the corticospinal tract (CST), can be caused by damage to various brain structures involved in motor function. Lesion studies conducted on animal models show, for example, how damage to the hand area of M1 is responsible for flaccidity and hypotonia of the contralateral limb (Fogassi et al., 2001). However, the degree of recovery of motor skills after a stroke greatly depends on proper brain plasticity and the activation of various other spared regions. Knowing the neural models and proceeding with an identification of damaged and preserved brain regions after a stroke, can allow to optimize and individualize therapeutic programs. Based on this hypothesis, a correlational pilot study was conducted here on a sample of 10 adult post-stroke patients with upper limb hemiparesis, in subacute and chronic phase. The analysis of MRI sequences allowed for the assessment of the extent of lesions and the degree of cerebral perfusion in each patient, whereas the motor perfomance was measured using clinical scales, such as: Box and Block Test (BBT), Motricity Index (MI), modified Rankin Scale (mRS) e modified Ashworth Scale (mAS). The primary qualitative neuroradiological analysis was integrated with segmentation and quantitative estimation of the severity of brain damage, using various investigative methods. A high variability of the compromised cortical areas was highlighted within the sample, while disconnections of specific white matter bundles were more frequent and coherent. Moreover, it emerged that a greater preservation of certain ipsilesional (IL) fiber tracts was positively associated with higher scores on the MI scale. Positive correlations were also found between the degree of perfusion in the selected ROIs and the functional state of patients, measured by the three scales MI, mAS and mRS. Lastly, the number of lesioned voxels in the IL hemisphere revealed an expected negative relationship with the Motricity Index score. This scale, commonly used to measure overall muscle strength in post-stroke hemiparesis, showed a more frequent and stronger correlation with the morphological data compared to the Box and Block test: a discrepancy likely associated with the small sample size. Overall, this research proposes the use of a multivariate and integrated approach to assessing motor function, through the use of different clinical scales. The in-depth analysis of the patient's pathological picture can therefore be useful, not only to predict performance, but also to guarantee the best planning of rehabilitation interventions.
Low-friction Silane-based Coating on Pharmaceutical Glass Vials: Development of Alternative Solutions to Standard Industrial Process
No full textThis PhD research, carried on in collaboration with Bormioli Pharma S.p.A., addresses the development of a sustainable lubricant coating for pharmaceutical glass vials, as a replacement for the current hot-end coating process, whose application involves toxic byproducts. Organosilane-based solutions were investigated to assess their environmental benefits and cost-effectiveness. In particular, an aqueous aminosilane was tested as an adhesion promoter for lubricant anchoring, together with an alternative single-component organosilane solution. Initial tests involved dip deposition, followed by spray application to assess scalability. Analytical characterizations confirmed that the aminosilane-primer effectively enables lubricant adhesion, protects the vial surface and allows scalable spray application. Mechanical tests, consisting in tribological and scratch resistance analyses, indicated effective lubrication, especially with the spray primer-lubricant mixture. The single-component solution also showed protective potential, although further investigation is needed. Overall, the silane primer approach offers significant sustainability and cost effectiveness, facilitating the transition to a single-step coating process. Future studies will aim to optimize primer-lubricant interactions and refine mechanical testing to better simulate rubbing on the production and filling lines
Analisi delle proprietà di scarica neuronali in primati non umani durante il sonno
No full textThe premotor cortex plays a crucial role in sensorimotor transformations, action planning, and
higher-order motor functions. While its activity during wakefulness has been extensively
characterized, its behavior during different brain states, such as sleep, remains largely
unexplored. In this study, we investigate the neural dynamics of motor and premotor cortical
areas in two rhesus macaques during the performance of a visuomotor task in a classical
neurophysiological setting and during subsequent unconstrained overnight sleep. Using
wireless intracortical recordings, we monitored local field potentials (LFPs), multi-unit activity
(MUA) and single-unit activity (SUA) across different brain states throughout the night. Based
on LFP and MUA signals, we developed a classification method to distinguish brain states from
the intracortically recorded signals. Next, we examined single neuron firing patterns across the
identified brain states, investigating their relationship with delta power, thus identifying distinct
neuronal groups. Additionally, we analyzed neuronal waveforms to gain a more comprehensive
characterization of neuronal diversity. Finally, through the visuomotor task, we functionally
categorized neurons. The integration of these analyses provided novel insights into the
properties of the premotor cortex beyond its classical role in motor control, suggesting a
reorganization of motor and premotor cortical activity during sleep and highlighting the
dynamic interplay between wakefulness and sleep states in the brain.La corteccia premotoria svolge un ruolo cruciale nelle trasformazioni sensorimotorie, nella
pianificazione delle azioni e nelle funzioni motorie di ordine superiore. Sebbene la sua attività
durante la veglia sia stata ampiamente caratterizzata, il suo funzionamento durante differenti
stati cerebrali, tra cui il sonno, rimane in gran parte inesplorato. Questo studio indaga le
dinamiche neurali delle aree corticali motorie e premotorie in due macachi rhesus durante un
compito visuomotorio in un contesto neurofisiologico classico e durante il sonno in condizioni
non vincolate. Utilizzando registrazioni wireless intracorticali abbiamo monitorato i potenziali
di campo locale (LFPs), l’attività multi-unitaria (MUA) e l’attività dei singoli neuroni (SUA)
nel corso dei diversi stati cerebrali in susseguirsi durante la notte. Sulla base dei segnali LFPs
e MUA abbiamo sviluppato un metodo di classificazione per distinguere gli stati cerebrali
basato unicamente sull’analisi di tali segnali intracorticali. Successivamente, abbiamo
analizzato i pattern di scarica dei singoli neuroni nei diversi stati cerebrali, indagando la loro
relazione con la potenza della banda di frequenza delta, identificando distinti gruppi neuronali.
Inoltre, abbiamo isolato le forme d’onda dei neuroni per ottenere una caratterizzazione più
completa della diversità neuronale. Infine, grazie al compito visuomotorio abbiamo
caratterizzato funzionalmente i neuroni. L’integrazione dei risultati emersi da queste indagini
ha fornito potenziali informazioni sulle proprietà della corteccia premotoria che vanno oltre il
suo classico ruolo di controllo motorio, suggerendo una riorganizzazione dell’attività corticale
motoria e premotoria durante il sonno e mettendo in evidenza l’interazione dinamica tra veglia
e stati di sonno nell’attività cerebrale
Self-commissioning and estimation techniques for sustainable synchronous reluctance motor drives in industrial applications
No full textQuesta tesi si concentra sullo sviluppo di tecniche di auto-commissioning e stima per i motori a riluttanza sincrona (SynRM), un'alternativa sostenibile ed efficiente ai tradizionali motori a induzione (IM) e ai motori sincroni a magneti permanenti (PMSM). I SynRM offrono alta efficienza, convenienza economica e indipendenza dai materiali rari, rendendoli ideali per applicazioni industriali.
I contributi principali includono algoritmi robusti per affrontare sfide come la non linearità degli inverter, gli effetti del dead-time e la stima dei parametri. Viene introdotto un osservatore basato su Phase-Locked Loop (PLL) per una precisa stima senza sensori della posizione del rotore e del flusso, eliminando la necessità di costosi sensori meccanici.
I metodi proposti semplificano l'installazione iniziale dei SynRM e migliorano le prestazioni del controllo motore, l'efficienza energetica e la robustezza del sistema. Le validazioni sperimentali dimostrano il potenziale dei SynRM per sostituire IM e PMSM in applicazioni come sistemi HVAC, pompe e sistemi di energia rinnovabile, aprendo la strada a future innovazioni nei controlli avanzati e nelle applicazioni ad alta potenza.This thesis focuses on developing self-commissioning and estimation techniques for Synchronous Reluctance Motors (SynRMs), a sustainable and efficient alternative to traditional Induction Motors (IMs) and Permanent Magnet Synchronous Motors (PMSMs). SynRMs offer high efficiency, cost-effectiveness, and independence from rare-earth materials, making them ideal for industrial applications.
Key contributions include robust algorithms for addressing challenges such as inverter nonlinearity, dead-time effects, and parameter estimation. A Phase-Locked Loop (PLL)-based observer is introduced for precise sensor-less rotor position and flux estimation, eliminating the need for costly mechanical sensors.
The proposed methods enable simplified plug-and-play SynRM setups and improve motor control performance, energy efficiency, and system robustness. Experimental validations demonstrate the potential of SynRMs to replace IMs and PMSMs in applications like HVAC systems, pumps, and renewable energy systems, paving the way for future innovations in advanced controls and high-power applications
Development of methods and technologies for the specific inhibition of enzymes relevant for low colour stability of fruit juices and nectars.
No full textThis thesis explores the development of methods and technologies for the specific
inhibition of enzymes relevant to the low colour stability of fruit juices and nectars. This
research was carried out in collaboration with the HiStabJuice project, funded by the
European Union’s Horizon 2020 program.
This research project comprises five articles on inhibiting
enzymes and maintaining colour stability in strawberry nectars. One of these articles
details how certain enzymes are deactivated and focuses on polyphenol oxidase,
peroxidase, pectin methylesterase, and polygalacturonase. It also explores methods, for
inhibiting these enzymes.
Manuscript 2 analysed how thermal and nonthermal methods impact the quality of
strawberry nectar in terms of factors, like viscosity, colour, enzymatic activity and
microbial content. In the following, third, manuscript the comparison was extended over
a six-week timeframe showing that processed nectars retained their colour better than
non-processed ones. A fourth manuscript studied the determinants of low colour stability
in strawberry nectars by multilinear regression analysis. The results of the analysis
revealed that storage time is the primary factor affecting the lightness of strawberry
nectars and sugar content plays a key role in the preservation of red colour and overall
colour saturation.
The final manuscript compared the energy consumption of thermal and non-thermal
technologies in strawberry nectar production. Non-thermal treatments were less energy-consuming than thermal treatments, especially at increased packaging volume.
This thesis gives insights into the enzymes responsible for the low colour stability of
strawberry nectars and other factors that contribute to the low colour stability of
strawberry nectars. The findings inform how the product quality and shelf-life extension
of strawberry nectars can be achieved
Biosintesi di PUFA in Fragilariopsis cylindrus: una chiave per comprendere il metabolismo adattato al freddo dei lipidi biologicamente attivi
No full textThe PhD project investigated the metabolic pathway for n-3 polyunsaturated fatty acid (PUFA) biosynthesis in the diatom Fragilariopsis cylindrus - a model cold-adapted eukaryote - with a focus on how temperature variations can influence PUFA production in view of Global Warming scenarios. First, putative gene sequences encoding the enzymes involved in this pathway were identified in silico. Sequence and structural analyses revealed features characteristic of cold-adapted proteins. F. cylindrus was then cultured in photobioreactors at 1°C – mimicking a normal Antarctic summer – and 7°C. The cells underwent genomic, transcriptomic, and lipidomic analyses. Genes associated with the PUFA biosynthetic pathway were amplified via PCR. Their cloning and sequencing uncovered multiple genetic variants not previously reported. Targeted fatty acid profiling provided insights into the composition and abundance of seven key metabolites in the PUFA biosynthetic pathway, suggesting that F. cylindrus maintains a stable PUFA accumulation mechanism, regardless of environmental temperature fluctuations. qRT-PCR analysis revealed downregulation of four out of the seven pathway genes in cells grown at 7°C, potentially contributing to metabolite homeostasis. CpG islands, which may serve as potential sites for epigenetic modifications and transcriptional regulation, were identified in four of the genes. To validate enzyme functions within the pathway, the enzymes were recombinantly expressed in Escherichia coli and Pichia pastoris, and enzyme assays utilizing whole-cell systems and analysed via mass spectrometry were performed using their putative substrates. For three enzymes, their roles in the PUFA biosynthetic pathway were experimentally confirmed. In an industrial placement at DNAPhone s.r.l. (PR, Italy), three analytical methods were developed to spectroscopically measure peroxide value, free fatty acids, and conjugated trienes in oils. The resulting kits were produced as test lots and distributed to beta-testers for evaluation. A kit for determining total polyphenol content is under development.
This PhD program was co-financed by the National Operational Programme Research and Innovation, supported by ESF REACT-EU resources. The project was conducted in collaboration with the National Research Council (CNR) in Naples, the Scottish Association for Marine Science (SAMS, Oban, UK), the British Antarctic Survey (BAS, UK) and the company DNAPhone s.r.l. (Parma, Italy)
Leghe Heusler e leghe ad alta entropia per refrigerazione magnetica e recupero del calore di scarto
No full textEnergy plays a fundamental role in modern society, significantly impacting daily activities. Moreover, the increasing demand for energy, driven by new technologies, contributes to a profound impact on the environment and society. The high energy consumption becomes even more concerning considering that over 70% of the energy is lost during the transformation processes required to convert primary energy carriers into energy services. Furthermore, most energy losses occur in the form of heat emitted at temperatures below 100°C. The necessity for more efficient energy conversion solutions and the exploration of methods to recover waste energy is becoming increasingly crucial for the scientific community.
Two promising fields within materials science addressing this challenge are magnetic refrigeration, which focuses on the development of more energy-efficient cooling technologies (magnetocaloric applications), and waste low-grade heat recovery (thermomagnetic applications).
This thesis aims to contribute to address these issues by synthesizing NiMn-based Heusler alloys and High Entropy Alloys, composed of elements considered environmentally and economically non-critical. The magnetic transitions in the synthesized alloys are all second-order, ensuring full reversibility of the phenomena under investigation.
The first part of the work focuses on the synthesis and magnetic characterization of various NiMnSn-based Heusler alloys, examining how the most relevant magnetic characteristics for magnetocaloric and thermomagnetic applications vary with changes in alloy composition. This analysis demonstrates the optimal applicability of NiMnSn-based Heusler alloys, as their Curie transitions cover a temperature range between 300 K and 350 K.
Additionally, the thesis presents the development and application of a thermomagnetic device that converts controlled heat into easily measurable mechanical energy, enabling comprehensive thermomagnetic analysis of the materials under operando conditions for the first time. This device was initially employed to test the thermomagnetic properties of three representative Heusler alloys: NiMnSn, NiMnIn, and NiMnCuGa. The results demonstrated, firstly, the potential of the thermomagnetic motor prototype as an effective testing platform for thermomagnetic generation designs, as well as the promise of NiMn-based second-order Heusler compounds for low-grade heat energy harvesting applications. Notably, the NiMnIn alloy could generate an electric power of 2.6 W/kg (20.4 mW/cm³), which significantly exceeds the power generated by other devices presented in the literature.
Subsequently, 3D-printed additive manufacturing rotors based on NiMnSn and NiMnIn with varying thicknesses were developed to evaluate their thermomagnetic properties. A straightforward composite filament production method enabled uniform dispersion of magnetic powders within a polymer matrix, allowing for the fabrication of rotors with different thicknesses. The findings indicated that an increased rotor surface-to-volume ratio correlated with higher power peaks, confirming previous observations. Notably, the power peak curves of the 3D-printed rotors exhibited a sharp peak near the alloy's transition temperature, reflecting a temperature dependence that aligned with simulated trends. The study underscored a promising relationship between rotor geometry and thermomagnetic performance.
Finally, two new high-entropy alloys, FeNiGaMnSi-based, were synthesized. Magnetic characterizations identified two second-order magnetic transitions near room temperature for both compositions, indicating the alloys' suitability for potential magnetocaloric and thermomagnetic applications. The magnetic entropy changes and the magnetic work generated in an ideal thermomagnetic cycle (Wm) were calculated for both alloys. The ΔS values were comparable to the highest reported values for rare-earth-free HEAs across the Curie transition, demonstrating strong magnetocaloric application potential for these synthesized HEAs. Additionally, the calculated Wm values were similar to those obtained for NiMn-based Heuslers, further suggesting promise for TM applications. Characterizations performed with the TM device confirmed these findings, showing for the first time that the synthesized HEAs are promising candidates for waste energy recovery, which enhances interest in this novel class of functional materials.
In conclusion, this work aims to present new and effective solutions for magnetic energy conversion applications, starting with the synthesis of functional materials with magnetic properties that can be easily tuned and concluding with the evaluation of their performance under operational conditions. This approach addresses the existing gap between the functional study of magnetic alloys and their practical applications.
The work has been carried out primarily at the Institute of Materials for Electronics and Magnetism of the National Research Council (IMEM-CNR), where all the activity on synthesis and fundamental characterization of the thermomagnetic materials has been realized. Thanks to the strong collaboration with the Department of Physics of the University of Parma it has been possible to characterize the magnetic properties of the materials produced, and to test their functional behaviour and application potential in a thermomagnetic prototype developed there. A stage at the University of Sevilla, Spain, allowed for the realization of composite filaments containing the thermomagnetic materials and their use for 3D printing thermomagnetic rotors that were tested in the prototype
In vivo administration of Cerium Oxide Nanoparticles restores cardiac dysfunction in a rat model of early diabetes
No full textBackground: An in-depth study of nanomaterials is believed to open new ways for the development of advanced devices, medications, and other highly specific, effective, and personalized applications, aiding in the early diagnosis and treatment of various diseases. In this context, cerium oxide nanoparticles (CeONPs) have become a focus of intense research due to their unique antioxidant and anti-inflammatory properties, high chemical stability, biocompatibility, and large reactive surface area. Consequently, in vivo administration of CeONPs may offer a new preventive strategy against cellular oxidative stress and myocardial inflammation, both of which play critical roles in the pathophysiology of diabetic cardiomyopathy. Using a rat model of early diabetes, we investigated the potential of CeONPs to reach the heart, ameliorate cardiac function altered even in the early stages of hyperglycaemia, and counteract diabetes-induced microenvironmental changes in myocardial tissue. Additionally, we studied the cardiac function both at organ and cellular level after the administration of CeONPs in control rats to ensure their safe application.
Methods: Adult Wistar rats with streptozotocin-induced type-1 diabetes (n = 29) were studied in comparison with a control group (n = 15). Diabetic rats were either untreated (n = 16) or treated with intraperitoneal injections of CeONPs three times a week (n = 13) for four weeks. At the end of the protocol, hemodynamics, cardiomyocyte contractility, and calcium transients were measured to assess cardiac performance. The potential cardioprotective mechanisms of CeONPs were also investigated through in vitro assays for ROS and RNS scavenging activity and transcriptomic analysis using real-time PCR.
Moreover, cardiac electrical function and arrhythmia vulnerability were evaluated using telemetric electrocardiographic analysis and transmission electron microscopy (TEM) was employed to confirm the presence, morphology, and subcellular localization of CeONPs in cardiac and hepatic tissues. To evaluate the effects of CeONPs on healthy animals, an additional study was conducted on 12 control (CTRL) rats treated with CeONPs in comparison with CTRL. After four weeks, hemodynamic parameters, cardiomyocyte contractile properties, and calcium transients were measured.
CeONPs were characterized, and their capacity to interact with proteins present in cardiac tissue were studied using LC-MS proteomic analysis.
Results: In vivo treatment with CeONPs in a rat model of early diabetes resulted in an improvement in contractile performance and calcium dynamics at the cellular level as well as a partial recovery in cardiac mechanical properties. The observed cardioprotective effects in diabetic rats appear to be driven by reductions in oxidative and nitrosative stress, along with modulation of the circNCX1/Sirt1/Nrf2 pathway which activates the antioxidant response. CeONPs were found in both cardiac and hepatic tissues and, most importantly, these internalized CeONP clusters did not induce any morphological changes or electrical alterations, including arrhythmias or exacerbation of the typical diabetic bradycardia. Protein binding studies indicated that CeONPs form a protein corona preferentially with proteins involved in cardiomyocyte contractility and mitochondrial function. Finally, the administration of CeONPs in healthy control rats confirmed the safety of the nanoparticles and treatment protocol, with evidence of enhanced cardiac contractile performance at both cellular and organ levels.
Conclusions: Our findings suggest that CeONPs may represent a novel, safe therapeutic strategy capable of preventing initial myocardial damage in the diabetic heart and slowing its progression toward an overt pathological condition
Psychoeducation in Bipolar Disorder according to the Colom-Vieta model : prospective cohort study of the last 5 years
No full textIl presente studio si propone di indagare l’efficacia della psicoeducazione secondo il modello Colom-Vieta nel trattamento del disturbo bipolare, con un duplice obiettivo: valutare il cambiamento clinico nei pazienti a seguito dell’intervento e identificare possibili fattori predittivi di risposta. Il lavoro si inserisce nel più ampio contesto della letteratura sull’efficacia degli interventi psicoeducativi, sempre più riconosciuti come strumenti fondamentali nella gestione del disturbo bipolare. La ricerca in oggetto ha adottato un disegno osservazionale retrospettivo di coorte. Il campione è costituito da 30 pazienti che hanno completato cicli di psicoeducazione condotti in cinque anni differenti e consecutivi tra il 2021 e il 2025. Per ciascun partecipante sono stati raccolti dati relativi agli episodi clinici e ai ricoveri nei 12 mesi precedenti e successivi all’intervento. Inoltre sono stati considerati i punteggi medi ottenuti durante le sessioni nei principali test psicometrici autosomministrati: BDI, ASRM, RCTQ e RRS. Sono state quindi condotte analisi inferenziali con t-test per dati appaiati e modelli di regressione lineare, anche in presenza di covariate cliniche e socio-demografiche. I risultati mostrano una tendenza complessiva al miglioramento dopo la psicoeducazione, in particolare rispetto alla frequenza degli episodi e ai ricoveri. La durata del disturbo si conferma come predittore clinico rilevante: un numero maggiore di anni di malattia è associato a un minor miglioramento. I punteggi medi nei test psicometrici – in particolare ASRM, RCTQ e, in parte, RRS – si associano a un miglioramento clinico suggerendo che la presenza, seppur lieve, di sintomi durante il trattamento potrebbe rappresentare un elemento favorevole alla ricezione dell’intervento psicoeducativo. Anche il punteggio medio del BDI, pur non raggiungendo la significatività, indica una direzione interessante che meriterebbe ulteriori approfondimenti.
Conclusioni
Le conclusioni sottolineano il valore della psicoeducazione nella gestione del disturbo bipolare e pongono l’attenzione sull’importanza di una maggiore caratterizzazione dei pazienti, soprattutto rispetto alla cronicità del disturbo e alla natura specifica dei sintomi, per migliorare l’efficacia degli interventi. Limiti come la numerosità del campione, la mancanza di alcune sottoscale e l’impossibilità di valutare la gravità globale del disturbo indicano la necessità di ulteriori studi. I dati raccolti, pur nella loro parzialità, suggeriscono che il miglioramento clinico è un processo multifattoriale e potenzialmente accessibile a tutti i pazienti
Assessment of Ga2O3-based Schottky diodes and hetero-junctions for applications in power electronics and UV detection
No full textIn this PhD thesis, Schottky barriers and p-n heterojunctions based on two polymorphs (β and κ phases) of gallium oxide (Ga2O3) were investigated. The study included diodes fabricated from the monoclinic β-Ga2O3 and the orthorhombic κ-Ga2O3, in both planar and vertical geometries. An extensive methodological, numerical, and experimental effort was made to get new information about the electro-optical characteristics of both polymorphs. The potential of the k-phase for solar-blind UV-C detectors, as well as that of the -phase for power devices was explored. Experimental and numerical studies on Si-doped κ-Ga2O3 provided a better understanding of the interplay between thermal treatments and trapping phenomena, a topic of considerable interest in both academic and industrial contexts.
NiO/β-Ga2O3 p-n diodes developed for UV photodetection were also studied. Such type of device demonstrated satisfactory performance even for a simple circular design with a diameter of less than 300 μm, which demonstrates that NiO/β-Ga2O3 p-n diodes may be profitably used for detecting UV-C signals in daylight conditions.
The extensive characterization of SnO/β-Ga2O3 p-n vertical power devices suggested a correlation between the p-type doping density of SnO and the concentration of interfacial traps in the heterojunction. The effect of such traps on the overall electrical properties of the devices was demonstrated.
Finally, the electric current crowding and corresponding thermal field in planar diodes based on β-Ga2O3 and κ-Ga2O3, under forward bias, was simulated using the Sentaurus TCAD suite. The simulation evidenced the crucial role of metal/semiconductor contact resistance and showed that extra doped pockets beneath the metal contact may be effective to reduce electric current crowding and correspondingly improve the thermal field uniformity and heat dissipation