The direct detection of gravitational waves from merging binary systems marked a major breakthrough in physics. As we move toward the era of precision physics with gravitational waves with next-generation space and ground-based interferometers, one key observable will be the tidal deformability of the coalescing objects. The tidal deformability is characterized in terms of complex coefficients, whose real (i.e., conservative) parts are often referred to as Love numbers. The Love numbers are important because they offer insights into the gravitational behavior and the body’s internal structure. In the case of black holes, they depend on the physics at the horizon and have been proven to be tightly related to the existence of a hidden symmetry structure in general relativity. The overarching goal of my program is to advance our understanding of the tidal response and Love numbers of black holes and compact objects in two main directions: the nonlinear response and the dynamical (i.e., nonstatic) regime. We will answer in particular the questions: What is the nonlinear response of a black hole under an external tidal perturbation? Are the recently discovered symmetries that are responsible for the vanishing of the linear Love numbers an "accident" of linear response theory or, do they admit a completion to all orders in general relativity? How do the symmetries get modified in the presence of nonstatic tides? Answering these questions will have important implications for our theoretical understanding of the fundamental properties of gravity in the strong-field regime and the symmetry structure of gravitational effective field theories, which we will be able to probe with future detectors.

Metal hydrides are essential for electrochemical energy storage. They are promising to safely store hydrogen in solid form and are used as active materials in Nickel-metal hydride rechargeable batteries. To improve the hydrogen absorption efficiency, to speed up the (de)hydrogenation kinetics and to increase the materials cyclability, two strategies are now considered: alloying and miniaturization. This however makes active materials investigations much more challenging due to the presence of nanostructured interfaces, heterogeneities among particles and nanoscopic changes in materials composition. The objective of the ECHoS project is then to develop advanced analytical strategies capable of probing operando the electrochemical insertion and release of hydrogen in solid materials from the nanoscale to the microscale. To achieve these challenging tasks and because hydrogen is the lightest chemical element, ECHoS relies on a highly sensitive optical interferometric scattering microscope (iSCAT) coupled to electrochemistry to visualize and quantify instantaneously the formation of metal hydride in different systems with high spatial and high temporal resolution. First employed at the single nanoparticle level, from palladium nanoparticles to more complex metal nano-alloys synthesized with novel nanoscale-confined electrodeposition methods, the nanoscale imaging technique extends to encompass ABy-type (2

Despite major advances in neurovascular research, stroke remains the second most common cause of death worldwide and a leading global cause of disability. Unravelling pathophysiological mechanisms might lead to the identification of new therapeutic targets, preventive approaches, and/or diagnostic biomarkers needed to rapidly and reliably identify patients with acute ischemic stroke, thus decreasing time to treatment and improving functional outcome. While initially discovered in neurons, recent studies show that Brain-Derived Neurotrophic Factor (BDNF) is a growth factor highly concentrated in blood platelets. Moreover, they show that exogenous BDNF activates isolated platelets in autocrine/paracrine manner while promoting fibrin clot lysis in purified system. According to our preliminary results, exogenous BDNF increases platelet adhesion to collagen and fibrinogen under arterial and venous shear stress, respectively, and enhances platelet clot retraction. It promotes thrombin generation while favoring clot lysis in plasma and decreasing clot firmness in whole blood. On the flip side, few studies show that BDNF induces oxidative stress and enhances local inflammation within atherosclerotic plaques. In the context of limited and conflicting available data, our translational research project aims at extensively investigating endogenous (i.e., circulating) BDNF in vitro effects on various platelet functions and interplay with leukocytes, coagulation, and fibrinolysis as well as in vivo in bleeding and ischemic stroke rat models and confirming our results ex vivo in a large stroke patient cohort. Our project is of utmost importance since it would confirm the emerging role of BDNF as a novel actor in hemostasis and thrombosis, thus might particularly lead to the development of novel strategies for rapid diagnosis, prevention and/or treatment of ischemic stroke and vascular cognitive impairment.