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PubblicazioneCooperative mixing through hydrodynamic interactions in Stylonychia lemnae( 2025)Aquatic microorganisms typically inhabit a heterogeneous resource landscape, composed of localized and transient patches. To effectively exploit these resources, they have evolved a wide range of feeding strategies that combine chemotactic motility with active feeding flows. However, there is a notable lack of experimental studies that examine how these active flows shape resource fields to optimize feeding. In particular, the suspected cooperative hydrodynamics provided by groups of cells remains largely unexplored due to the difficulties in visualizing these dynamic three-dimensional flows. Here, we experimentally investigate how Stylonychia lemnae ciliates form feeding clusters of independent cells around food patches. Individual feeding flows interact hydrodynamically to create a chaotic collective flow at the population scale. Using a combination of experimental and numerical techniques, we measure and predict the entire collective flow, enabling us to assess its remarkable mixing and dispersion properties. We show that the active spreading of the food patch accelerates its detection by starving cells. As many fitness advantages provided by collective flows can be envisioned, we propose that this feeding cluster represents a form of intraspecific by-product cooperative behavior.
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PubblicazioneContinuum limit for discrete NLS with memory effect( 2025)We consider a discrete nonlinear Schrödinger equation with longrange interactions and a memory effect on the infinite lattice hZ with mesh-size h > 0. Such models are common in the study of charge and energy transport in biomolecules. Because the distance between base pairs is small, we consider the continuum limit: a sharp approximation of the system as h → 0. In this limit, we prove that solutions to this discrete equation converge strongly in L2 to the solution to a continuous NLS-type equation with a memory effect, and we compute the precise rate of convergence. In order to obtain these results, we generalize some recent ideas proposed by Hong and Yang in L2based spaces to classical functional settings in dispersive PDEs involving the smoothing effect and maximal function estimates, as originally introduced in the pioneering works of Kenig, Ponce and Vega. We believe that our approach may therefore be adapted to tackle continuum limits of more general dispersive equations.
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PubblicazioneQuantum computing for chemistry and physics applications from a Monte Carlo perspective( 2024)This Perspective focuses on the several overlaps between quantum algorithms and Monte Carlo methods in the domains of physics and chemistry. We will analyze the challenges and possibilities of integrating established quantum Monte Carlo solutions into quantum algorithms. These include refined energy estimators, parameter optimization, real and imaginary-time dynamics, and variational circuits. Conversely, we will review new ideas for utilizing quantum hardware to accelerate the sampling in statistical classical models, with applications in physics, chemistry, optimization, and machine learning. This review aims to be accessible to both communities and intends to foster further algorithmic developments at the intersection of quantum computing and Monte Carlo methods. Most of the works discussed in this Perspective have emerged within the last two years, indicating a rapidly growing interest in this promising area of research.
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PubblicazionePro-inflammatory small extracellular vesicles: neuroinflammation propagation and target spinal cord cells in explant cultures(SISSA, 2025-12-02)Within the vast landscape of intercellular messengers, extracellular vesicles, namely membrane-enclosed nanosized-particles released by virtually all cells, are increasingly tied to central nervous system transcellular communication, yet their roles in propagating neuro-inflammation, in kindling astrocytic reactivity and neuronal dysfunctions, as well as the relationship among vesicle source cells and the recipient ones, remain largely unclear. To dissect extracellular vesicles’ dynamics and their still-elusive impact on neuron-glia interactions, we collect and separate vesicles from cultured ex-vivo organ spinal explants immuno-challenged by a cytokines’ cocktail. Inflammation-released vesicles are isolated either by ultracentrifugation or by size exclusion chromatography, identified by ultramicroscopy and immunoblot, and transferred to naïve spinal explants, devoid of inflammatory features. We report that spinal extracellular vesicles, only when released during cytokine treatment, act as pro-inflammatory messengers and trigger a distinct temporal pattern of tissue reactivity by spreading spinal reactivity to naïve astrocytes, neurons and microglia in recipient slices. We combine live calcium imaging, electrophysiology, confocal microscopy and Luminex assay to depict changes in astrocytic calcium events, neuronal synaptic activity and microglia morphology, as well as the emergence of pro-inflammatory cytokines and chemokines in recipient spinal organ slices. By delivering cre-packing extracellular vesicles to cre-reporter Ai9 organ explant slices, we further indicate that, even when cre-packing is selectively transduced only by neurons, astrocytes are pro-inflammatory vesicles’ preferential cell recipients.
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PubblicazioneData-driven global stability of vertical planar liquid jets by dynamic mode decomposition on random perturbations( 2022)A data-driven approach to estimate the global spectrum of gravitational planar liquid jets (sheet or curtain flows) is presented in this work. The investigation is carried out by means of two-dimensional numerical simulations performed through the solver BASILISK, based on the one-fluid formulation and the volume-of-fluid approach. The dynamic mode decomposition technique is applied to extract the underlying linear operator, considering random perturbations of the base flow. The effectiveness of this procedure is first evaluated comparing results with those of a simplified one-dimensional curtain model in terms of spectrum and eigenfunctions. The methodology is then applied to a two-dimensional configuration obtaining the BiGlobal spectra for both supercritical (Weber number We > 1) and subcritical (We < 1) regimes. Results highlight that in supercritical regime, the spectrum presents three branches: the upper and lower ones exhibit a purely sinuous behavior with frequencies quite close to those predicted by the one-dimensional model; the middle branch presents a predominant varicose component, increasing with the frequency. The subcritical spectrum, instead, shows that the first two less stable eigenvalues, sorted by increasing frequency, exhibit, respectively, a sinuous and a varicose behavior, while their growth rate is almost the same. As expected, the subcritical regime does not reveal the slow branch. The effect of the density ratio, r ρ, between the two phases is investigated, revealing that the flow system is unstable for r ρ > 0.05. Topological inspections of the leading modes in this unstable configuration show that the predominance of a varicose behavior is related to the rupture of the curtain.