DSpace Community:http://hdl.handle.net/2445/84822024-03-28T06:27:36Z2024-03-28T06:27:36ZExploring optimal graphene slit-pore width for the physical separation of water-methanol mixtureBellido Peralta, RogerLeoni, FabioCalero Borrallo, CarlesFranzese, Giancarlohttp://hdl.handle.net/2445/2084922024-03-12T17:02:13Z2024-03-06T18:46:29ZTitle: Exploring optimal graphene slit-pore width for the physical separation of water-methanol mixture
Author: Bellido Peralta, Roger; Leoni, Fabio; Calero Borrallo, Carles; Franzese, Giancarlo
Abstract: Efficient and sustainable techniques for separating water- alcohol mixtures are in high demand in the industry. Recent research has revealed that nanotechnology could be the optimal solution. In this study, we investigate how the width of a nano-confining graphene slit-pore affects the filtration and purification of water-methanol mixtures. Using Molecular Dynamics simulations of a coarse-grained model for mixtures containing up to 25 percent methanol, we found that specific pore sizes segregate the two components, with water being preferred in the center and methanol accumulating near the hydrophobic walls. Altering the pore width also affects non-monotonically the diffusivity of each component, with water diffusing faster than methanol. Hence, optimal pore size, leveraging segregation and diffusion differences, can enable the successful extraction of both components. However, the system requires external forces and work to maintain mechanical stability at specific pore widths. Our research indicates that Å pore size maximizes physical separation, ensuring that the energy cost of a filtering graphene membrane is minimized.2024-03-06T18:46:29ZHydrophobic Homopolymer’s Coil–Globule Transition and Adsorption onto a Hydrophobic Surface under Different ConditionsDurà Faulí, BernatBianco, ValentinoFranzese, Giancarlohttp://hdl.handle.net/2445/2084912024-03-12T17:02:13Z2024-03-06T18:38:40ZTitle: Hydrophobic Homopolymer’s Coil–Globule Transition and Adsorption onto a Hydrophobic Surface under Different Conditions
Author: Durà Faulí, Bernat; Bianco, Valentino; Franzese, Giancarlo
Abstract: Unstructured proteins can modulate cellular responses to environ- mental conditions by undergoing coil−globule transitions and phase separation. However, the molecular mechanisms of these phenomena still need to be fully understood. Here, we use Monte Carlo calculations of a coarse-grained model incorporating water’s effects on the system’s free energy. Following previous studies, we modeled an unstructured protein as a polymer chain. Because we are interested in investigating how it responds to thermodynamic changes near a hydrophobic surface under different conditions, we chose an entirely hydrophobic sequence to maximize the interaction with the interface. We show that a slit pore confinement without top-down symmetry enhances the unfolding and adsorption of the chain in both random coil and globular states. Moreover, we demonstrate that the hydration water modulates this behavior depending on the thermodynamic parameters. Our findings provide insights into how homopolymers and possibly unstructured proteins can sense and adjust to external stimuli such as nanointerfaces or stresses.2024-03-06T18:38:40ZCrossover from three-dimensional to two-dimensional systems in the nonequilibrium zero-temperature random-field Ising modelSpasojevic, D.Mijatovic, S.Navas Portella, VíctorVives i Santa-Eulàlia, Eduardhttp://hdl.handle.net/2445/2084342024-03-12T17:02:13Z2024-03-05T15:56:52ZTitle: Crossover from three-dimensional to two-dimensional systems in the nonequilibrium zero-temperature random-field Ising model
Author: Spasojevic, D.; Mijatovic, S.; Navas Portella, Víctor; Vives i Santa-Eulàlia, Eduard
Abstract: We present extensive numerical studies of the crossover from three-dimensional to two-dimensional systems in the nonequilibrium zero-temperature random-field Ising model with metastable dynamics. Bivariate finite-size scaling hypotheses are presented for systems with sizes L °ø L °ø l which explain the size-driven critical crossover from two dimensions (l = const, L→∞) to three dimensions (l ∝ L→∞). A model of effective critical disorder Reffc (l,L) with a unique fitting parameter and no free parameters in the Reffc (l,L→∞) limit is proposed, together with expressions for the scaling of avalanche distributions bringing important implications for related experimental data analysis, especially in the case of thin three-dimensional systems.2024-03-05T15:56:52ZWater under extreme confinement in graphene: Dynamics, structure, and hydration pressure explained as a function of the confinement widthCalero Borrallo, CarlesFranzese, Giancarlohttp://hdl.handle.net/2445/2082912024-03-12T17:02:13Z2024-03-01T14:05:23ZTitle: Water under extreme confinement in graphene: Dynamics, structure, and hydration pressure explained as a function of the confinement width
Author: Calero Borrallo, Carles; Franzese, Giancarlo
Abstract: Graphene nanochannels are relevant for their possible applications, as in water purification, and for the challenge of understanding how they change the properties of confined liquids. Here, we use all-atom molecular dynamics simulations to investigate water confined in an open graphene slit-pore as a function of its width w, down to sub-nm scale. We find that the water translational and rotational dynamics exhibits an oscillatory dependence on w, due to water layering. The oscillations in dynamics correlate with those in hydration pressure, which can be negative (hydrophobic attraction), or as high as ~1 GPa, as seen in the experiments. At pore widths commensurable with full layers (around 7.0 Å and 9.5 Å for one and two layers, respectively), the free energy of the system has minima, and the hydration pressure vanishes. These are the separations at which the dynamics of confined water slows down. Nevertheless, the hydration pressure vanishes also where the free energy has maxima, i.e., for those pore-widths which are incommensurable with the formation of well-separated layers, as w ≃ 8.0 Å. Around these values of w, the dynamics is faster than in bulk, with water squeezed out from the pore. This behavior has not been observed for simple liquids under confinement, either for water in closed nano-pores. The decomposition of the free energy clarifies the origins of the dynamics speedups and slowdowns. In particular, we find that the nature of the slowdown depends on the number of water layers: for two layers, it is due to the internal energy contribution, as in simple liquids, while for one layer, it has an entropic origin possibly due to the existence of a hydrogen-bond network in water. Our results shed light on the mechanisms ruling the dynamics and thermodynamics of confined water and are a guide for future experiments.2024-03-01T14:05:23ZNetwork Topology in Water Nanoconfined between Phospholipid MembranesMartelli, FaustoCrain, JasonFranzese, Giancarlohttp://hdl.handle.net/2445/2082632024-03-27T13:58:46Z2024-03-01T13:28:27ZTitle: Network Topology in Water Nanoconfined between Phospholipid Membranes
Author: Martelli, Fausto; Crain, Jason; Franzese, Giancarlo
Abstract: Water provides the driving force for the assembly and stability of many cellular components. Despite its impact on biological functions, a nanoscale understanding of the relationship between its structure and dynamics under soft confinement has remained elusive. As expected, water in contact with biological membranes recovers its bulk density and dynamics at ∼1 nm from phospholipid headgroups but surprisingly enhances its intermediate range order (IRO) over a distance, at least, twice as large. Here, we explore how the IRO is related to the water’s hydrogen-bond network (HBN) and its coordination defects. We characterize the increased IRO by an alteration of the HBN up to more than eight coordination shells of hydration water. The HBN analysis emphasizes the existence of a bound–unbound water interface at ∼0.8 nm from the membrane. The unbound water has a distribution of defects intermediate between bound and bulk water, but with density and dynamics similar to bulk, while bound water has reduced thermal energy and many more HBN defects than low-temperature water. This observation could be fundamental for developing nanoscale models of biological interactions and for understanding how alteration of the water structure and topology, for example, due to changes in extracellular ions concentration, could affect diseases and signaling. More generally, it gives us a different perspective to study nanoconfined water.2024-03-01T13:28:27ZResonant and Off-Resonant Magnetoacoustic Waves in Epitaxial Fe3Si/GaAs Hybrid StructuresRovirola Metcalfe, MarcWaqas Khaliq, MuhammadCasals, BlaiFoerster, MichaelNiño, Miguel AngelAballe, LucíaHerfort, JensHernández Ferràs, JoanMacià Bros, FerranHernández Mínguez, Albertohttp://hdl.handle.net/2445/2069732024-03-12T17:02:13Z2024-02-01T14:58:06ZTitle: Resonant and Off-Resonant Magnetoacoustic Waves in Epitaxial Fe3Si/GaAs Hybrid Structures
Author: Rovirola Metcalfe, Marc; Waqas Khaliq, Muhammad; Casals, Blai; Foerster, Michael; Niño, Miguel Angel; Aballe, Lucía; Herfort, Jens; Hernández Ferràs, Joan; Macià Bros, Ferran; Hernández Mínguez, Alberto
Abstract: Surface acoustic waves (SAWs) provide an efficient dynamical coupling between strain and magnetization in micro- and nanometric systems. Using a hybrid device composed of a piezoelectric, GaAs, and a ferromagnetic Heusler alloy thin film, Fe3Si, we are able to quantify the amplitude of magnetoacoustic waves generated with SAWs via magnetic imaging in an x-ray photoelectron microscope. The cubic anisotropy of the sample, together with a low damping coefficient, allows for the observation of resonant and nonresonant magnetoelastic coupling. Additionally, via micromagnetic simulation, we verify the experimental behavior and quantify the magnetoelastic shear strain component in Fe3Si, which appears to be large (b2=10±4MJm−3).2024-02-01T14:58:06ZDiffusion capacity of single and interconnected networksSchieber, Tiago A.Carpi, LauraPardalos, Panos M.Masoller, CristinaDíaz Guilera, AlbertRavetti, Martín G.http://hdl.handle.net/2445/2069692024-03-12T17:02:13Z2024-02-01T14:48:54ZTitle: Diffusion capacity of single and interconnected networks
Author: Schieber, Tiago A.; Carpi, Laura; Pardalos, Panos M.; Masoller, Cristina; Díaz Guilera, Albert; Ravetti, Martín G.
Abstract: Understanding diffusive processes in networks is a significant challenge in complexity science. Networks possess a diffusive potential that depends on their topological configuration, but diffusion also relies on the process and initial conditions. This article presents Diffusion Capacity, a concept that measures a node's potential to diffuse information based on a distance distribution that considers both geodesic and weighted shortest paths and dynamical features of the diffusion process. Diffusion Capacity thoroughly describes the role of individual nodes during a diffusion process and can identify structural modifications that may improve diffusion mechanisms. The article defines Diffusion Capacity for interconnected networks and introduces Relative Gain, which compares the performance of a node in a single structure versus an interconnected one. The method applies to a global climate network constructed from surface air temperature data, revealing a significant change in diffusion capacity around the year 2000, suggesting a loss of the planet's diffusion capacity that could contribute to the emergence of more frequent climatic events.2024-02-01T14:48:54ZDemagnetizing field-induced magnetocaloric effect in GdBadosa Felip, QuimMañosa, LluísVives i Santa-Eulàlia, EduardPlanes Vila, AntoniWeise, BrunoBeyer, LukasStern Taulats, Enrichttp://hdl.handle.net/2445/2069022024-03-12T17:02:13Z2024-02-01T10:04:49ZTitle: Demagnetizing field-induced magnetocaloric effect in Gd
Author: Badosa Felip, Quim; Mañosa, Lluís; Vives i Santa-Eulàlia, Eduard; Planes Vila, Antoni; Weise, Bruno; Beyer, Lukas; Stern Taulats, Enric
Abstract: We have studied the impact of demagnetizing fields on the magnetocaloric effect of commercial-grade gadolinium plates. Adiabatic temperature changes ( ) were measured for magnetic fields applied along the parallel and perpendicular directions of the plates. The differences in the obtained values were accounted for by differences in the internal field due to demagnetizing effects. A combination of calorimetric measurements under a magnetic field and thermometric measurements has enabled us to obtain Brayton cycles for the two different magnetic field orientations. It has been found that the refrigerant capacity for a Brayton cycle working at 1.6 T around room temperature reduces from to J kg when the demagnetizing factor changes from = 0.035 to for the parallel and perpendicular configurations, respectively. It has been shown that it is possible to obtain significant demagnetizing field-induced magnetocaloric effects by rotating the sample in a region of a constant applied magnetic field. The refrigerant capacity of a Brayton cycle around room temperature for a T constant applied magnetic field is J kg . The feasibility of these demagnetizing field-induced effects has been confirmed by direct thermometric measurements, which reveal adiabatic temperature changes of 1 K when the sample is rotated between the perpendicular and parallel configurations.2024-02-01T10:04:49ZNeuron-derived extracellular vesicles contain synaptic proteins, promote spine formation, activate TrkB-mediated signalling and preserve neuronal complexitySolana Balaguer, JúliaCampoy Campos, GenísMartín Flores, NúriaPérez Sisqués, LeticiaSitjà Roqueta, LaiaKucukerden, MelikeGámez Valero, AnaColl Manzano, AlbertMartí Puig, EulàliaPérez Navarro, EstherAlberch i Vié, JordiSoriano i Fradera, JordiMasana Nadal, MercèMalagelada Grau, Cristinahttp://hdl.handle.net/2445/2068062024-03-12T17:02:13Z2024-01-31T12:41:57ZTitle: Neuron-derived extracellular vesicles contain synaptic proteins, promote spine formation, activate TrkB-mediated signalling and preserve neuronal complexity
Author: Solana Balaguer, Júlia; Campoy Campos, Genís; Martín Flores, Núria; Pérez Sisqués, Leticia; Sitjà Roqueta, Laia; Kucukerden, Melike; Gámez Valero, Ana; Coll Manzano, Albert; Martí Puig, Eulàlia; Pérez Navarro, Esther; Alberch i Vié, Jordi; Soriano i Fradera, Jordi; Masana Nadal, Mercè; Malagelada Grau, Cristina
Abstract: Extracellular vesicles (EVs) play an important role in intercellular communication as carriers of signalling molecules such as bioactive miRNAs, proteins and lipids. EVs are key players in the functioning of the central nervous system (CNS) by influencing synaptic events and modulating recipient neurons. However, the specific role of neuron-to-neuron communication via EVs is still not well understood. Here, we provide evidence that primary neurons uptake neuron-derived EVs in the soma, dendrites, and even in the dendritic spines, and carry synaptic proteins. Neuron-derived EVs increased spine density and promoted the phosphorylation of Akt and ribosomal protein S6 (RPS6), via TrkB-signalling, without impairing the neuronal network activity. Strikingly, EVs exerted a trophic effect on challenged nutrient-deprived neurons. Altogether, our results place EVs in the spotlight for synaptic plasticity modulation as well as a possible therapeutic tool to fight neurodegeneration.2024-01-31T12:41:57ZThree-state opinion model with mobile agentsFerri, IreneGaya Àvila, AinaDíaz Guilera, Alberthttp://hdl.handle.net/2445/2063662024-03-12T17:02:13Z2024-01-25T18:37:13ZTitle: Three-state opinion model with mobile agents
Author: Ferri, Irene; Gaya Àvila, Aina; Díaz Guilera, Albert
Abstract: We study an agent-based opinion model with two extreme (opposite) opinion states and a neutral intermediate one. We adjust the relative degree of conviction between extremists and neutrals through a dimensionless parameter called the 'neutrality parameter' to investigate its impact on the outcome of the system. In our model, agents move randomly on a plane with periodic boundary conditions and interact with each other only when they are within a fixed distance threshold. We examine different movement mechanisms and their interplay with the neutrality parameter. Our results show that in general, mobility promotes the global consensus, especially for extreme opinions. However, it takes significantly less time to reach a consensus on the neutral opinion.2024-01-25T18:37:13Z