Parkinson's disease: autoimmunity and neuroinflammation

Parkinson's disease is a neurodegenerative disease that causes the death of dopaminergic neurons in the substantia nigra. The resulting dopamine deficiency in the basal ganglia leads to a movement disorder that is characterized by classical parkinsonian motor symptoms. Parkinson's disease is recognized as the most common neurodegenerative disorder after Alzheimer's disease. PD ethiopathogenesis remains to be elucidated and has been connected to genetic, environmental and immunologic conditions. The past decade has provided evidence for a significant role of the immune system in PD pathogenesis, either through inflammation or an autoimmune response. Several autoantibodies directed at antigens associated with PD pathogenesis have been identified in PD patients. This immune activation may be the cause of, rather than a response to, the observed neuronal loss. Parkinsonian motor symptoms include bradykinesia, muscular rigidity and resting tremor. The non-motor features include olfactory dysfunction, cognitive impairment, psychiatric symptoms and autonomic dysfunction. Microscopically, the specific degeneration of dopaminergic neurons in the substantia nigra and the presence of Lewy bodies, which are brain deposits containing a substantial amount of α-synuclein, have been recognized. The progression of Parkinson's disease is characterized by a worsening of motor features; however, as the disease progresses, there is an emergence of complications related to long-term symptomatic treatment. The available therapies for Parkinson's disease only treat the symptoms of the disease. A major goal of Parkinson's disease research is the development of disease-modifying drugs that slow or stop the neurodegenerative process. Drugs that enhance the intracerebral dopamine concentrations or stimulate dopamine receptors remain the mainstay treatment for motor symptoms. Immunomodulatory therapeutic strategies aiming to attenuate PD neurodegeneration have become an attractive option and warrant further investigation

Correlazione tra proprietà e struttura di una ghisa vermicolare

LAUREA SPECIALISTICAIl ciclo produttivo di un rocchetto in ghisa CGI250 impiegato per l’avvolgimento di fili tessili prevede, dopo la fusione del getto, un trattamento termico di ricottura per garantire al pezzo la lavorabilità alle macchine utensili. L’azienda ha eseguito prove di lavorazione su rocchetti non trattati, riscontrando dei problemi di usura e rottura dell’utensile, senza però rilevare grandi diversità a livello metallurgico tra la ghisa trattata e quella non trattata . La tesi quindi si focalizzerà sulla caratterizzazione dei due materiali, con lo scopo di evidenziare le differenze e di determinare il motivo per cui la ghisa non trattata mostri problemi di lavorabilità, pur avendo caratteristiche simili a quella ricotta. Difficoltà ulteriori per lo studio derivano dal fatto che il materiale impiegato è poco diffuso sia in fonderia che in letteratura: si tratta di una ghisa sferoidale degradata in vermicolare e mostra una microstruttura molto eterogenea. La geometria del rocchetto è inoltre assai complicata, con forti variazioni di spessore e pure la morfologia delle cave per l’avvolgimento del filo è molto complessa, soprattutto per le lavorazioni alle macchine utensili.The production cycle of a textile reel made of CGI250 schedules an heat treatment (annealing) to assure the machinability on the tool machines. Fondershell made a machining experiment on the untreated reel, finding tool problems but not great metallurgical differences between the untreated iron and the treated one. The thesis will focalize on the characterization of the two materials, aiming to highlight the differences and to understand why the untreated iron shows machinability problems, although having similar characteristics to the annealed one. Further difficulties derive from the fact that this kind of cast iron is rarely spread both in foundry and in literature: the examined material is a spheroidal graphite iron degradated to compacted graphite iron. Besides, the geometry of the reel is very complex, with great thickness variations and the morphology of the quarries for the reeling is as well very complicated, in particular for the tool machinin

A study on the application of ultrasonic EMAT technology to defect detection in rails

LAUREA MAGISTRALEAffinché le conseguenze catastrofiche dovute alla rottura di un binario vengano evitate, la loro integrità va garantita. Considerata la grande quantità di binari presenti, questi vengono solitamente ispezionati con sistemi in movimento quali treni diagnostici equipaggiati per controlli ultrasonori, dopodiché, squadre di operatori sono mandate a controllare in maniera più approfondita laddove siano state segnalate eventuali anomalie. Una delle potenziali zone di rottura del binario è rappresentata dal piede, dove cricche da fatica possono nucleare e crescere fino a rottura. La particolare forma della sezione della rotaia, congiuntamente alla necessità di lavorare esclusivamente dalla testa del binario durante un’ispezione in movimento, provoca frequentemente la non corretta ispezione di tale zona. Gli EMAT (electro-magnetic acoustic transducers) sono sensori in grado di generare differenti tipologie di onde ultrasonore in materiali magnetici, con la particolarità di non richiedere il contatto con la parte ispezionata. In questa tesi, vengono studiate le potenzialità di un sistema EMAT per la rilevazione di difetti nel piede di rotaia, con l’obiettivo di ottenere un sistema di ispezione dinamico. Nello specifico, due tipologie di onde ultrasonore vengono utilizzate: le onde convenzionali e e le onde guidate. Utilizzando le onde convenzionali, sono state realizzate una serie di prove, sia in maniera statica che dinamica, su un gruppo di difetti artificiali di dimensioni via via crescenti, il tutto utilizzando un carrello progettato e realizzato per la movimentazione dei sensori. Il sistema è stato poi montato su di un carrello ferroviario situato su un tratto di armamento con difetti artificiali, in modo da emulare le condizioni reali di un ispezione. In maniera simile, in una prima parte le onde guidate vengono utilizzate in maniera statica, dopo aver condotto analisi numeriche sui modi di vibrare del binario, su un tratto di rotaia integra, per studiarne il comportamento. Dopodiché, una serie di test sia statici che dinamici viene eseguita sul tratto di armamento già citato, con e senza l’utilizzo del carrello ferroviario.The integrity of railway rails must be guaranteed to avoid the catastrophic consequences that their failure could induce. Because of the high amount of rails present, they are usually tested by means of an in-movement system such as diagnostic trains equipped with ultrasonic instrumentation, then, teams of operators are sent to perform more accurate inspections where anomalies are reported. One of the potential failure zones of the rail is represented by the foot, where semi elliptical fatigue cracks may nucleate and grow. The peculiar shape of the rail section in conjunction with the necessity to work, during an in-movement test, exclusively from the rail head, causes the usually adopted ultrasonic probes not to carefully inspect this part of the section. Electro-magnetic acoustic transducers (EMAT) are sensors able to generate different type of ultrasonic waves in magnetic materials, with the peculiarity of avoiding contact with the part to be inspected. In this thesis work, the potentialities of EMAT technology for defect detection in the rail foot are studied, with the goal of obtaining a dynamic inspection solution. Specifically, two types of ultrasonic waves are studied: bulk waves and guided waves. Concerning the ultrasonic bulk waves, tests are performed both statically and dynamically on a set of artificial defects of increasing size, supported by the design and realization of a trolley for the sensor movement. Eventually, the instrumentation is mounted on a railway bogie placed on a segment of permanent way having artificial defects to emulate real testing conditions. Similarly, guided waves are firstly utilized in a static configuration, after a numerical investigation about rail natural frequencies, on a segment of intact rail, to study their behaviour. Then, tests are performed statically and dynamically on the same permanent way defects with and without the bogie

VAD-CLVA: Integrating CLIP with LLaVA for Voice Activity Detection

Voice activity detection (VAD) is the process of automatically determining whether a person is speaking and identifying the timing of their speech in an audiovisual data. Traditionally, this task has been tackled by processing either audio signals or visual data, or by combining both modalities through fusion or joint learning. In our study, drawing inspiration from recent advancements in visual-language models, we introduce a novel approach leveraging Contrastive Language-Image Pretraining (CLIP) models. The CLIP visual encoder analyzes video segments focusing on the upper body of an individual, while the text encoder processes textual descriptions generated by a Generative Large Multimodal Model, i.e., the Large Language and Vision Assistant (LLaVA). Subsequently, embeddings from these encoders are fused through a deep neural network to perform VAD. Our experimental analysis across three VAD benchmarks showcases the superior performance of our method compared to existing visual VAD approaches. Notably, our approach outperforms several audio-visual methods despite its simplicity and without requiring pretraining on extensive audio-visual datasets

[Cinq vignettes, découpées et remontées, en-tête de papiers de diverses administrations ou représentants du peuple] : [estampe]

Collectionneur : Vinck, Carl de (1859-1931). CollectionneurRéférence bibliographique : De Vinck, 7221Appartient à l’ensemble documentaire : Est19VinckPapier à en-têt