Dynamics of membrane nanotubes coated with I-BAR

Membrane deformation is a necessary step in a number of cellular processes such as filopodia and invadopodia formation and has been shown to involve membrane shaping proteins containing membrane binding domains from the IRSp53-MIM protein family. In reconstituted membranes the membrane shaping domains can efficiently deform negatively charged membranes into tubules without any other proteins present. Here, we show that the IM domain (also called I-BAR domain) from the protein ABBA, forms semi-flexible nanotubes protruding into Giant Unilamellar lipid Vesicles (GUVs). By simultaneous quantification of tube intensity and tubular shape we find both the diameter and stiffness of the nanotubes. I-BAR decorated tubes were quantified to have a diameter of ~50 nm and exhibit no stiffening relative to protein free tubes of the same diameter. At high protein density the tubes are immobile whereas at lower density the tubes diffuse freely on the surface of the GUV. Bleaching experiments of the fluorescently tagged I-BAR confirmed that the mobility of the tubes correlates with the mobility of the I-BAR on the GUV membrane. Finally, at low density of I-BAR the protein upconcentrates within tubes protruding into the GUVs. This implies that I-BAR exhibits strong preference for negatively curved membranes

Proteomic analysis at the sites of clinical infection with invasive Streptococcus pyogenes

Invasive Streptococcus pyogenes infections are rare, with often-unexplained severity. Prompt diagnosis is desirable, as deaths can occur rapidly following onset and there is an increased, but preventable, risk to contacts. Here, proteomic analyses of clinical samples from invasive human S. pyogenes infections were undertaken to determine if novel diagnostic targets could be detected, and to augment our understanding of disease pathogenesis. Fluid samples from 17 patients with confirmed invasive S. pyogenes infection (empyema, septic arthritis, necrotising fasciitis) were analysed by proteomics for streptococcal and human proteins; 16/17 samples had detectable S. pyogenes DNA. Nineteen unique S. pyogenes proteins were identified in just 6/17 samples, and 15 of these were found in a single pleural fluid sample including streptococcal inhibitor of complement, trigger factor, and phosphoglycerate kinase. In contrast, 469 human proteins were detected in patient fluids, 177 (38%) of which could be identified as neutrophil proteins, including alpha enolase and lactotransferrin which, together, were found in all 17 samples. Our data suggest that streptococcal proteins are difficult to detect in infected fluid samples. A vast array of human proteins associated with leukocyte activity are, however, present in samples that deserve further evaluation as potential biomarkers of infection

Genetic Basis of Myocarditis: Myth or Reality?

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Embodied Joint Agency in Human-Robot Interactions

Tese de mestrado, Ciência Cognitiva, 2023, Universidade de Lisboa, Faculdade de CiênciasRecent technological advances illustrated that artificial agents such as robots are increasingly present in our societies and lives. Yet, the examination of how interactions with artificial agents such as robots impact the human sense of self, sense of agency and sense of embodiment remains unclear. This thesis aimed to examine the relationship between (dis)-embodiment, sense of self and sense of joint agency in human-robot interactions (HRI). Specifically, I focused on Depersonalization (DP), a condition characterized by distressing feelings of being detached from one’s self and body, sometimes described by people as “feeling like a robot”. Two overarching research questions guided my inquiry: 1) what is the effect of atypical bodily self-experiences, as measured by traits of DP, on higher-order processes involved in social interactions with robots; and 2) what is the effect of interacting with a humanoid robot on humans’ sense of self, embodiment, and (joint) agency. Two studies were conducted to gain insights on these aims: a) a correlation analysis on the relationship between traits of DP and negative attitudes towards robots, and b) an in-person experiment implementing a joint agency task with a robot and a human. Our findings reveal a significant positive correlation between DP traits and negative attitudes towards robots. Namely: higher traits of DP correspond to more negative attitudes towards robots. Furthermore, findings from the second phase suggest that participants feel more depersonalized after compared to before interacting with the robot, while the opposite trend was displayed for human-human interactions. Our findings highlight a connection between DP traits and general attitudes towards robots and suggests that interacting with robots might cause increased states of DP. Ultimately, the current analyses hold relevance for the field of social robotics, philosophical questions surrounding human selfhood and the nature of robots, and ethical concerns related to integration of such technologies into our societies

Seismic Response of Wind Turbines: Time Domain Simulations Including SSI

This thesis presents the time-domain seismic response of a parked wind turbine with a skirted foundation exposed to soil-structure interaction. The wind turbine is discretized using the finite element program ABAQUS/CAE and the response in terms of displacements, accelerations, shear and moments along the tower height is computed using two comparative models.The fully integrated model and the simplified spring model demonstrated to be capableof simulating the seismic behaviour of a wind turbine tower accounting for SSI-effects; even with the relatively simple modeling techniques used. The models are restricted to the linearly elastic range and assume that the foundation is fully bounded to the soil during seismic excitation.The main contribution in this thesis is a parametric study which investigates changes in peak responses along the tower for different foundation geometries. The foundation radius and depth is independently varied and the same seismic excitation is applied to the spring model in all simulations. It is shown that an increase in the flexibility of the foundation gives larger peak responses along the tower for all the geometries considered. The corresponding fixed-base solution is shown to highly underestimate the seismic loads for certain geometries. This observation illustrates the importance of including the effects of soil-structure interaction for tall and slender structures