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Hemispheric lateralization of emotions and encoding trustworthiness of faces : processes in comparison
No full textDiverse fonti in letteratura suggeriscono che espressione e percezione delle emozioni sarebbero funzioni lateralizzate. In particolare, è stato ipotizzato che l’espressione emotiva sia più intensa nell’emifaccia sinistra, a causa di una maggiore specializzazione dell’emisfero destro per questa funzione. Allo stesso tempo, la prevalenza dell’emisfero destro nel guidare l’attenzione sarebbe responsabile di maggiore sensibilità percettiva nell’emicampo sinistro, il che potenzierebbe la percezione di emozioni espresse in maniera più debole nell’emifaccia destra rispetto alla sinistra. Ho sottoposto queste ipotesi a controllo empirico utilizzando un campione di foto postate in rete, ipotizzando i) prevalenza di pose che mostrano l’emifaccia sinistra, e ii) espressività potenziata quando l'emifaccia sinistra viene presentata nell’emicampo sinistra (a seguito dell’inversione speculare della fotografia). Sono stati studiati inoltre la direzione dello sguardo, il sesso, l’etnicità e l’età apparente. Infine, al dato sull’intensità dell’emozione espressa dal volto è stato aggiunto quello sulla sua affidabilità percepita, che rappresenta un aspetto più specifico e presumibilmente più ben definito delle qualità espressive. I risultati documentano una preferenza per sguardi diretti verso l’osservatore e per volti di sesso femminile. Questi sono stati giudicati come più espressivi e come maggiormente affidabili. Anche l’età sembra un fattore rilevante per valutazione emozionale e per l’affidabilità. Si è visto che i bambini e gli anziani sono percepiti come più espressivi e maggiormente affidabili. In contrasto con la letteratura, i dati non hanno invece evidenziato effetti legati all’emifaccia o all’emicampo di presentazione. La tesi si conclude con una discussione delle implicazioni teoriche di questi risultati, in particolare per quanto riguarda le teorie sulla comunicazione non verbale nei media digitali. Viene proposta inoltre un’ipotesi di spiegazione per la mancata conferma degli effetti di emifaccia ed emicampo.
High-Pressure Processing for fruit juices: a non-thermal treatment alternative to improve the quality of red berry juices with a focus on the role of oxidative enzymes
No full textRed berries juices like strawberries, sour cherries, and red grapes offer both flavor and health benefits but are prone to spoilage and enzymatic degradation. Traditional thermal processing contribute to mantain the products safety but compromises their quality. High-Pressure Processing (HPP) emerges as a non-thermal alternative, preserving juices while retaining nutrients and flavors. This study assesses HPP's effectiveness in microbial control and enzymatic inactivation in addition to biomolecule's stability, optimizing parameters for red berry juices. Packaging's role in shelf stability is also explored. Results aim to improve red berry juice quality, meeting consumer demands for minimally processed, nutritious products
Esplorazione visiva di scene naturali dinamiche in macachi in libera visione
No full textNell'ambito di studio del sistema visivo, stimoli semplici come punti o barre luminose hanno storicamente ricoperto un ruolo fondamentale per delineare la struttura dei campi recettivi dei neuroni retinici e corticali. Tuttavia, è raro che l'input sensoriale proveniente dal mondo reale sia composto da pattern semplici e isolati. Sono sempre più numerose le evidenze che sottolineano la necessità di indagare l'elaborazione visiva in contesti di libera visione e con l’ausilio di stimoli naturalistici che, riflettendo la complessità e il dinamismo degli ambienti reali, sono sia più rilevanti da un punto di vista funzionale, che, talvolta, efficaci nell'elicitare l'attività neuronale. Nel presente lavoro, introduciamo un paradigma che permette uno studio ecologicamente rilevante dei meccanismi anatomo-fisiologici dell'elaborazione e dell'attenzione visiva nella via visiva sottocorticale del macaco, dove studi che utilizzano paradigmi di visione naturale sono ancora pochi. Inoltre, in fase preliminare all'acquisizione neurale, abbiamo analizzato il comportamento oculare per verificare se, ed in che misura, questo sia riproducibile tra diverse presentazioni di stesse o differenti clip e se fattori attentivi, sia di alto che basso livello, o il livello generale di engagement attentivo possano avere un'influenza sul comportamento oculare. Dai risultati emerge come l’allocazione dell'attenzione nei primati sia influenzato sia da fattori di alto livello, come la presenza di conspecifici, sia da proprietà di basso livello, come la salienza degli stimoli. Tuttavia, questi fattori determinano solo raramente pattern oculari altamente riproducibili, che sembrano verificarsi principalmente in scene poco complesse e statiche oppure quando il livello di salienza è particolarmente elevato. Inoltre, dalle nostre analisi emerge che, quando il tempo medio di osservazione del video è alto, attenzione e durata dello sguardo tendono ad essere diretti in egual misura verso tutte le categorie di stimolo presentate, mentre quando il tempo in cui lo sguardo rimane focalizzato sul video è solo leggermente superiore rispetto a quando è diretto altrove, gli stimoli che raffigurano conspecifici catturano l'attenzione in maniera più forte e sostenuta rispetto a quanto fatto dagli stimoli non biologici, suggerendo un ruolo prioritario per gli stimoli conspecifici e socialmente rilevanti nel dirigere l'attenzione e i movimenti oculari, superando gli effetti della salienza.In the study of the visual system, basic artificial stimuli such as spots or bars of light have been
instrumental in uncovering the receptive field (RF) structure of retinal and cortical neurons,
serving as pivotal milestones in vision research. Yet, the sensory input encountered in realworld
scenarios is rarely composed of such isolated simple patterns. A growing body of
evidence emphasizes the critical need to investigate visual processing within the context of
active natural vision, showing that naturalistic stimuli, mirroring the complexity and dynamism
of real-world environments, are not only more functionally relevant but also occasionally more
effective in eliciting neuronal responses. Here, we introduce a paradigm that facilitates an
ecologically valid exploration of the anatomical and physiological mechanisms of visual
processing and attention in the macaque's early vision pathway, where studies utilizing
naturalistic paradigms are still lacking. Moreover, in a preliminary phase prior to neural
acquisition, we conducted analyses of ocular behavior to verify whether, and to what extent of
ocular behavior follows repeatable patterns across repeated presentations of the same vs
different clips, and to determine if high- and low-level properties of the stimuli or the overall
level of attentional engagement drive the observed variability. The results show that attentional
deployment in primates is influenced by both high-level factors, such as the presence of
conspecifics, and low-level features, like salience of the stimuli. However, these factors rarely
result in highly reproducible ocular patterns, particularly in simple, static scenes or when
salience is elevated. Additionally, our examination of attentional engagement levels reveals that
while attention and gaze duration tend to be consistent across various content categories when
the average looking time towards the movie throughout the session is high, when the time in
which the gaze is directed at the video window is slightly higher than when it is directed
elsewhere, stimuli featuring primates capture attention more strongly and sustainably compared
to non-biological stimuli. This suggests a predominant role for conspecific and socially relevant
stimuli in directing attention and eye movements, surpassing the effects of saliency alone
Data visualization to support food packaging
No full textL’elaborato finale si pone come obiettivo l’esplorazione della visualizzazione di dati nel contesto del packaging alimentare. La sfida consiste nel restituire graficamente informazioni in grado di fornire all’utente una panoramica sul prodotto che guidi ad un acquisto consapevole. Tramite lo studio della letteratura e di casi pratici verranno analizzate le tecniche più efficaci per arrivare allo sviluppo di un prototipo che integri queste soluzioni e influenzi positivamente le scelte d’acquisto. The thesis aims to explore data visualization in the context of food packaging. The challenge is to return graphically all those information that can provide the user with an overview of the product that guides to a conscious purchase. The study of literature and practical cases will analyze the most effective techniques to develop a prototype which integrates these solutions and positively influences the purchasing choices
Advanced Graph-Based Detection for Wireless Channels
No full textLow-complexity graph-based algorithms provide a useful and powerful tool to limit the huge computational load typically encountered in the design of wireless communications receivers. This thesis focuses on the development of efficient detection techniques aimed at achieving an optimal trade-off between computational complexity and performance.
Specifically, in the context of single-carrier time-varying channels affected by fading or strong phase noise, this research examines approximate message-passing schemes based on the expectation propagation framework.
The primary objective is to develop a detection algorithm that, besides solving the complexity problem, operates effectively even with a reduced number of pilot symbols for the channel estimation process, thereby increasing the payload efficiency and improving adaptability to various communication standards. Moreover, current state-of-the-art algorithms rely on turbo iterations between the detector and decoder to refine estimates of both data and channel parameters. However, this approach introduces significant computational complexity, which is generally impractical, and the communication between the two units can sometimes be unfeasible. These limitations further motivate the research presented in this thesis.
Additionally, this work addresses the detection problem for Orthogonal Time Frequency Space (OTFS)-based transmissions in challenging high-mobility conditions. It proposes a message-passing algorithm that leverages the particular structure of the equivalent channel matrix in the Doppler-delay domain, aiming to reach the performance benchmark with affordable complexity under realistic channel conditions.
The performance of the proposed solutions is evaluated by assessing bit error rate and pragmatic capacity through MATLAB-based numerical simulations. The results demonstrate satisfactory performance, suggesting that the proposed approaches provide a viable low-complexity alternative to the existing methods. These findings offer practically implementable solutions in the receiver design for future research and applications
Collateral ligament lesion of the proximal interphalangeal joint in horses: an innovative approach for reconstruction
No full textThe collateral ligaments of the proximal interphalangeal joint are situated on either side
of the PIP joint, stabilizing the joint during movement by preventing excessive lateral
(side-to-side) motion. The PIP joint is essential for horses’ locomotion and overall
performance. Injury or damage to the collateral ligaments can lead to joint instability,
lameness, and can also affect the horse's ability to perform effectively. Typically, collateral
ligament injuries and PIP joint lesions are treated with arthrodesis, a surgical procedure
that fuses the joint. However, this type of fixation can result in a reduced range of motion,
an in increased risk of infections, and in a diminished quality of life for the affected horses.
Nowadays, innovative techniques that may offer better prognoses and outcomes for
horses suffering from acute lesions have been developed.
The objective of this thesis is to introduce a new surgical technique for reconstructing the
collateral ligament of the proximal interphalangeal joint (PIPJ) by utilizing an autologous
tendinous graft sourced from the lateral digital extensor tendon (LDET) of the horse's hind
limb. This ligament reconstruction technique aims to eliminate the need for performing
arthrodesis, as the graft would fulfill the role of the damaged collateral ligament and help
stabilize the joint.
This thesis details two ex vivo experimental surgeries conducted on the hind limbs of two
equine cadavers: the first specimen was obtained from an 8-month-old foal, while the
second came from an 8-year-old adult horse. Both horses were treated at the Veterinary
Teaching Hospital of the University of Turin and were euthanized for reasons unrelated
to any PIPJ lesions.
The LDET was harvested and prepared with specialized sutures to achieve the desired
graft configuration. Subsequently, the graft was fixed in the anatomical position of the
collateral ligament, which had been transected before the experiment to simulate the
injury. Two bone tunnels were drilled under interoperative radiography guidance, and the
graft was then secured using a surgical button and an interference screw.
As this thesis serves as a preliminary study, further research and testing will be necessary
to successfully implement this technique in vivo
Learning to ignore emotional distractors: repetition, affective context and long-term effects
No full textIt is well known that prolonged experience with certain stimuli modulates their significance in the priority map and leads to a diminished allocation of our attention to them. The present thesis aims to explore the extent to which repetition of the same set of stimuli is effective in supporting a learning process that shapes the attentional filter and allows us to ignore distractors, through the process known as habituation. The primary focus is on understanding how the exposure to repeated task-irrelevant stimuli, particularly emotional ones (both pleasant and unpleasant) might influence the way attention is captured by these images. Additionally, the goal is to determine which stage of emotional processing is affected by this experience, through both behavioral and cortical measures. Finally, we have explored how the habituation mechanisms are influenced by the introduction of a change in the context of experience disrupting its stability, as well as by the lack of exposure to the stimuli themselves for a certain period.
To test this, in Experiment 1, the impact of the repetition of distractors was examined by content (i.e., pleasant, unpleasant, and neutral), showing that emotional interference completely habituated with repetition and promptly recovered with novelty. At the cortical level, the enhanced LPP for emotional pictures was attenuated by repetitions, and stimulus novelty only affected emotional, but not neutral distractors in both the RTs and LPP. Alpha-ERD was similarly reduced for repeated emotional and neutral distractors.
To better understand how flexible the habituation mechanisms are in novel emotional contexts, in Experiment 2 novel distractors (pleasant or unpleasant or neutral) were introduced among repeated pictures. This prompted a dishabituation response at the behavioral level (i.e., recovery of the response after the habituation) which was more evident in the unpleasant context. Moreover, when novel pictures depicted pleasant contents (i.e., erotica), the dishabituation to unpleasant distractors was attenuated. The LPP and the Alpha-ERD were highly modulated by distractor emotional contents (i.e., trial type), and this modulation persisted across repetitions. Both cortical responses were strongly enhanced when novel pictures were introduced after the habituation phase.
Experiment 3 aims to measure the persistence of the habituation over time, that is, the effect of a lack of exposure to the stimulus on habituation. The same set of stimuli were repeated in a habituation phase and, after a day of rest, a test phase. Behavioral interference for emotional stimuli was still reduced by the habituation in the test phase and recovered by the subsequent introduction of new stimuli.
The different responses observed at the behavioral and cortical levels correspond to different stages of the elaboration of the stimuli. This suggests that the initial stages of evaluation, where we assess and categorize stimuli, are crucial and supported by the engagement with our motivational systems. This engagement is sustained, and it is reflected in the affective modulation of the Late Positive Potential (LPP).
The human brain has the ability to selectively disregard emotionally irrelevant stimuli once the initial evaluation has taken place. This adaptive capability, to overcome the tendency for emotional stimuli to capture our attention, does not occur spontaneously but it is developed through the experience with distracting events. Essentially, it is a learned response originated as a result of the strategy to ignore the distractors and the implicit learning that certain emotional cues hold no significant consequence.
In general, this mechanism of inhibition is also sensitive to specific contextual perturbation, like the introduction of novel emotional stimuli and the temporary lack of stimulation, which modulate the response to the already habituated stimuli. In summary, this suggest that cognitive mechanisms enable us to prioritize and filter out emotional distractors after evaluating their significance, emphasizing the importance of implicit learning and context of experience in shaping our response to emotional stimuli
FOODTURE: Analysis and development of the social fridge "Frigo di Quartiere" project by Im.patto Nova Coop
No full textIl presente lavoro di tesi analizza l'iniziativa “Frigo di Quartiere”, nata con Nova Coop per ridurre lo spreco alimentare e sostenere le comunità vulnerabili, attraverso la redistinazione delle eccedenze dai punti vendita ai Frigo. L’obiettivo è realizzare un toolkit per Nova Coop facilitando la creazione di un manuale destinato alle cooperative, con raccomandazioni su formazione, linee guida, exhibit design e riconoscibilità, per favorire la replicabilità del modello in contesti già esistenti e nuovi.This thesis work analyzes the “Frigo di Quartiere” initiative established with Nova Coop to reduce food waste and support vulnerable communities through the redistination of surplus from stores to Fridges. The goal is to create a toolkit for Nova Coop by facilitating the creation of a manual for use by cooperatives, with recommendations on training, guidelines, exhibit design and recognizability, to encourage replicability of the model in existing and new contexts
Rischio poligenico e volumetria cerebrale : uno studio sulla malattia di Alzheimer
No full textStudy assumptions: Polygenic risk scores (PRSs), which are based on the additive effect of multiple loci across the genome are used to assess an individual’s genetic predisposition to AD by aggregating the effects of multiple genetic variants. Studies have shown that higher polygenic scores for AD, in healthy adults, and in clinical populations, are associated with reduced regional brain volumes related to AD and cognitive decline, especially including the APOE ε4 allele among the pool of genes of interest.
Study scope: this study aimed to investigate the relationship between polygenic risk scores (PRSs) and brain volumes in specific areas associated with Alzheimer’s disease.
Materials and methods: 342 participants were recruited from the Alzheimer’s Disease Neuroimaging Initiative (ADNI), then participants were divided on their Aβ positivity and their grey matter fraction (GMF) to form three groups: amyloid-positive atrophic (AP), amyloid- negative normal (NN), and amyloid-positive normal (NP). Subsequently, the analyses were carried out.
Results and conclusions: the results of this study confirm the association between polygenic risk scores (PRSs) and volumetric reduction in specific brain areas involved in Alzheimer's disease, as well as the significant role of the APOE ε4 allele in contributing to the risk of developing the disease. This highlights the importance of PRSs as a possible predictive tool.Assunzioni dello studio: I polygenic risk scores (PRS), che si basano sull'effetto additivo di più loci considerando tutto il genoma, vengono utilizzati per valutare la predisposizione genetica individuale alla malattia di Alzheimer (AD) aggregando gli effetti di più varianti genetiche. Studi hanno dimostrato che punteggi poligenici più elevati per l'AD, sia in adulti sani che in popolazioni cliniche, sono associati a una riduzione dei volumi cerebrali di aree correlate all'AD e al declino cognitivo, in particolare considerando il peso dell'allele APOE ε4 tra i geni di interesse.
Obiettivo dello studio: questo studio mirava a indagare la relazione tra i polygenic risk scores (PRS) e i volumi cerebrali in specifiche aree associate alla malattia di Alzheimer.
Materiali e metodi: 342 partecipanti sono stati reclutati dall'Alzheimer’s Disease Neuroimaging Initiative (ADNI), successivamente i partecipanti sono stati suddivisi in base alla positività all'amiloide (Aβ) e alla frazione di materia grigia (GMF) per formare tre gruppi: amiloide-positivo atrofico (AP), amiloide-negativo normale (NN) e amiloide-positivo normale (NP). Successivamente, sono state condotte le analisi.
Risultati e conclusioni: i risultati di questo studio confermano l'associazione tra i polygenic risk scores (PRS) e la riduzione volumetrica in specifiche aree cerebrali coinvolte nella malattia di Alzheimer, così come il ruolo significativo dell'allele APOE ε4 nel contribuire al rischio di sviluppare la malattia. Questo evidenzia l'importanza dei PRS come possibile strumento predittivo
Inibizione dell’acquisizione del ferro da parte di Staphylococcus aureus: un doppio approccio avente come bersaglio proteine coinvolte nei pathways mediati da emofori e siderofori
No full textIn the upcoming decades, one of the biggest risks to public health will be antimicrobial resistance (AMR), with Staphylococcus aureus being one of the most threatening multidrug resistant pathogens. Indeed, in 2017 the World Health Organization (WHO) drew up a Global Priority Pathogen list for antibiotic-resistant bacteria, indicating S. aureus methicillin and vancomycin resistant variants as a “high priority”. Furthermore, during the COVID-19 pandemic, the battle against AMR had faded into the background, contributing even more to its strengthening and diffusion.
Iron acquisition has been demonstrated as a necessity for S. aureus pathogenicity in human infections. Indeed, the human host has evolved a defense mechanism, called "nutritional immunity", that regulates iron trafficking in an effort to lessen free iron toxicity and inhibit microbial growth. In turn, S. aureus has developed different strategies to overcome the host nutritional immunity, as the hemophore and siderophore-mediated systems for iron retrieval. The former bacterial strategy involves the Iron-regulated Surface Determinant (Isd) system enabling iron acquisition from the host hemoglobin (Hb), while the latter consists of small iron chelators that retrieve the iron bound to host proteins in the extracellular compartment. The Isd system consists of nine proteins, called hemophores, of which IsdB and IsdH are found on the bacterium surface and are involved in Hb binding and in the extraction and transfer of the heme to the downstream Isd effectors. In this context, only IsdB out of the two surface-exposed hemophores has been identified as an S. aureus virulence factor, essential for the bacterium pathogenesis. Despite different efforts have been reported in literature to develop antibacterials or vaccines targeting IsdB, no product has become commercially available yet, leaving ground for strategy improvements.
At the same time, S. aureus has also evolved strategies for the retrieval of inorganic iron from the extracellular media of the host, mainly involving Staphyloferrin A (SA) and Staphyloferrin B (SB) siderophores. Both siderophores have been identified as S. aureus virulence factors, but only SB has been reported to be produced by the most invasive strains, and thus considered to be the greatest support of virulence. Within the SB biosynthetic pathway, the first step is catalysed by SbnA which, in concerted action with SbnB-catalysed reaction, produces two out of three building blocks needed for SB synthesis. The mutation of either sbnA or sbnB genes resulted in the abrogation of SB production, highlighting the key role of the two enzymes. A complete structural and functional characterization of SbnA has not been reported in literature yet, and no strategies have been described targeting the enzyme. In this context, the characterization of SbnA structural and functional properties and the identification of potential inhibitors would provide a potential combined strategy for the development of new antimicrobials targeting S. aureus iron acquisition pathways.
Within the PhD project, an in-house developed immunoassay was exploited as a platform for the evaluation of molecules that interfere with IsdB-Hb complex formation. Notably, three commercial compounds, which had been previously identified, were re-synthesized by Prof. Lazzarato group (University of Turin) and evaluated in this thesis by the immunoassay. The group of Prof. Lazzarato synthesized also different analogues for all three compounds, designed to alleviate the solubility and/or stability issues that were previously encountered. No significant improvements in terms of potency were highlighted by the immunoassay when comparing the derivatives to their parent compounds, therefore further modifications will be required.
The thesis project also encompassed the optimization of the conditions for the recombinant expression in E. coli and the purification of SaSbnA. The purified protein was characterized in its functional and regulatory properties by spectroscopic techniques, as UV-Vis and fluorescence spectrophotometry, as well as by an ad hoc optimized activity assay. Notably, the optimization of a continuous activity assay allowed to confirm that SaSbnA uses a ping-pong kinetic mechanism with substrate inhibition by L-glutamate. After the enzyme characterization, three assays were set up and validated for the evaluation of potential inhibitors of SaSbnA activity. The assays’ optimization allowed the assessment of both the effect of potential inhibitors on SaSbnA activity and their direct binding to the enzyme. For the activity evaluation, a discontinuous assay was optimized to provide a high-throughput evaluation of a broad number of molecules to have a first selection for compounds with a significative inhibitory effect. Subsequently, the optimized continuous assay was exploited for the characterization of the mechanism of action of the active molecules, with the determination of inhibition constants. At last, the binding of the active molecules to SaSbnA was evaluated by fluorescence spectroscopy. The defined testing platform was then exploited to study the effect of intermediates of the SB pathway on SaSbnA activity to potentially identify feedback mechanisms. Among the intermediates, citrate was analysed more carefully since previous studies highlighted its inhibitory effect on two other enzymes of the SB pathway, and its presence was identified in a SaSbnA structure (PDB ID 5D85). Indeed, the intermediate was identified as an active inhibitor, highlighting a more complex regulatory mechanism within the SB pathway. At last, the assays were exploited to test in vitro the first set of molecules, with the identification of one hit inhibitor, which was then further characterized, evaluating its mechanism of action, and measuring inhibition constants. A first derivative of the lead compound was synthesized by collaborators at the University of Turin and was tested using the same platform, highlighting a more potent molecule.
The project also involved the production of a second construct for SaSbnA expression, which was designed for high throughput screening (HTS) experiments due to its improved yields. The purified protein was then exploited in an HTS of compound libraries to find potential inhibitors of SaSbnA activity. The discontinuous activity assay was optimized for HTS conditions and then exploited to screen compound libraries made available by the CEA Paris-Saclay centre. The HTS identified seven molecules that inhibited the activity of SaSbnA by 50% or more at 50 µM concentration. These selected hits were confirmed by further analyses and a preliminary characterization allowed to identify the best compounds for further tests and improvements