Dipòsit Digital de la Universitat de Barcelona
El Dipòsit Digital de la Universitat de Barcelona és el repositori institucional que conté en format digital els materials derivats de l'activitat docent, investigadora i institucional de la comunitat universitària.
Enviaments recents
ArticleSimulación aplicada al aprendizaje activo en asignaturas de Ingeniería Química y Química Analítica.(Congrés Internacional de Docència Universitària i Innovació (CIDUI), 2025) Bringué Tomàs, Roger; Bonet i Ruiz, Jordi; Plesu Popescu, Alexandra Elena; Torres, Ricard; Soto López, Rodrigo; Cabello Gallego, Ruben; Bayarri Ferrer, Bernardí; Labanda, Jordi; Núñez Burcio, Oscar; Fuguet i Jordà, Elisabet; Benavente Moreno, Fernando J. (Julián); Beltrán Abadia, José LuisThe development of the strategic line of Simulation applied to active learning in Chemical Engineering and Analytical Chemistry subjects has been a success. Four actions have been designed based on the incorporation of simulation tools in activities for two compulsory subjects of the Chemistry and Chemical Engineering degrees and two practical laboratory subjects of the Chemical Engineering degree. The software and materials needs for the institution are diverse, from almost zero to very demanding. Three of these actions have been implemented with very positive results in terms of acceptance by the students.- ArticleOctyl levulinate biolubricant production from levulinic acid esterification over ion exchange resins: Role of morphology and reaction thermodynamics(Elsevier B.V., 2025-05-26) Badia i Córcoles, Jordi Hug; Soto, Rodolfo; Fité Piquer, Carles; Tejero Salvador, Xavier; Ramírez Rangel, ElianaSynthesis of biolubricant octyl levulinate (OL) through liquid-phase esterification of levulinic acid with 1-octanol over ion-exchange resins (IERs) was studied. OL possesses excellent properties for application as biomass-derived lubricant, like moderate viscosity, high viscosity index, and low volatility, and it can be considered a completely renewable value-added product, ready for mass-consumption. An unprecedented catalytic screening using acidic IERs revealed that the present reaction is sensitive to catalyst morphology, with structures easing molecular accessibility towards active sites being more active than IERs with greater active sites concentrations. The most active IERs were the gel-type resin Dowex®50Wx2, a micro-structured resin with low-density polymer regions, and the hyper-crosslinked macroreticular resin Macronet™ MN500, with highly exposed acid sites due to large macropore-sized cavities. Equilibrium conversions were experimentally determined in a batch reactor at 2.5 MPa and 353 − 393 K, with values ranging 35–97 %, revealing a slight exothermic character for the reaction. Thermodynamic equilibrium properties for the reaction were determined experimentally for the first time. Enthalpy, entropy, and Gibbs free energy changes of reaction at 298.15 K were estimated to be −(6.9 ± 0.3) kJ/mol, (5.051 ± 0.016) J/(mol·K), and −(8.5 ± 0.3) kJ/mol, respectively.
- ArticleSilicon-based nanopillars: a novel platform for tissue applications(Royal Society of Chemistry, 2025-12-21) Piergallini, Cristiano ; Díaz Valdivia, Natalia; Deyà, Alba; Fernández Nogueira, Patricia; Singh, Rahul ; Bertelsen, Christian Vinther; Svendsen, Winnie Edith; Corominas, Montserrat (Corominas Guiu); Gombau, Lourdes ; Sanz Fraile, Héctor; Reguart, Noemí; Romano Rodríguez, Albert; Serras Rigalt, Florenci; Luna, Noemí de ; Alcaraz Casademunt, Jordi; Ollé Monge, MartaNanostructured surfaces are increasingly used for cell applications due to their enhanced interactions with numerous cell types; yet, their effects on tissues remain unexplored. To address this limitation, we designed vertical silicon nanopillar (Si-NP) arrays with high density, high aspect ratio and submicrometer diameter, as an optimized geometry based on previous cell-nanostructure studies. Using state-of-the-art in vitro and ex vivo assays, we examined adhesion and biocompatibility of biological samples of different origin and level of complexity -human epithelial-like cell lines, Drosophila imaginal discs and patient-derived lung cancer biopsies-laid on Si-NP arrays or unpatterned flat Si surfaces. Our results demonstrated that Si-NP arrays significantly improved cell and tissue adhesion while preventing oxidative damage and early apoptosis. Consistently, focused ion beam-scanning electron microscopy imaging of cells and tissues showed extended horizontal protrusions and limited vertical wrapping around Si-NP, revealing enhanced cell-NP interactions without cell/tissue penetration. In contrast, flat Si surfaces showed poor adhesion, increased apoptosis, and failed to support tumor biopsy attachment. Interaction with Si-NP arrays upregulated reactive oxygen species (ROS), yet mitochondria-associated ROS remained unchanged, and consequently apoptosis was not induced, indicating that the increased ROS arose from non-mitochondrial compartments and did not compromise viability. Notably, Si-NP arrays matched or outperformed biological responses on tissue culture plastic and Transwell-based assays, which are common in vitro and ex vivo substrates, respectively. These findings provide the first demonstration of the biological suitability of Si-NP arrays for tissue applications in research and clinical translation.
- Treball de fi de grauNeural networks for hadron resonance extraction(2026-06) Garcia Clapés, Guim; Gonzalez-Solis De La Fuente, Sergi; Montaña Faiget, GlòriaWe present a neural network approach to resonance parameter extraction and model classification applied to the pion vector form factor. Five theoretical parametrizations of the ρ(770) resonance of increasing sophistication are considered, ranging from simple Breit-Wigner models to fully analytic implementations derived from Chiral Perturbation Theory. Trained exclusively on synthetic spectra, the networks recover the physical pole parameters with precision comparable to traditional χ2 fits in a single inference step. Extended to simultaneous parameter extraction and model classification, a multitask network consistently identifies the parametrization that best describes the experimental data, in agreement with traditional fitting results, while extracting the model parameters with comparable precision. The resulting fast, single-step inference framework opens the door to future applications in hadronic physics
- ArticleModelling Public Opinion Dynamics: The Spiral of silence in clustered homophilic networks(Elsevier Ltd., 2026) Castillo Corullón, Judit; Cozzo, EmanuelePublic discourse emerges from the interplay between individuals’ willingness to voice their opinions and the structural features of the social networks in which they are embedded. In this work we investigate how choice homophily and triadic closure shape the emergence of the spiral of silence, the phenomenon whereby minority views are progressively silenced due to fear of isolation. We advance the state of the art in three ways. First, we integrate a realistic network formation model, where homophily and triadic closure co-evolve, with a mean-field model of opinion expression. Second, we perform a bifurcation analysis of the associated Q-learning dynamics, revealing conditions for hysteresis and path dependence in collective expression. Third, we validate our theoretical predictions through Monte Carlo simulations, which highlight the role of finite-size effects and structural noise. Our results show that moderate triadic closure can foster minority expression by reinforcing local cohesion, whereas excessive closure amplifies asymmetries and entrenches majority dominance. These findings provide new insights into how algorithmic reinforcement of clustering in online platforms can either sustain diversity of opinion or accelerate its suppression.