Artículos (Física de la Materia Condensada)

URI permanente para esta colecciónhttps://hdl.handle.net/11441/10869

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The impact of interfacial quality and nanoscale performance disorder on the stability of alloyed perovskite solar cells
(Nature Research, 2024-10-30) Frohna, Kyle; Chosy, Cullen; Al-Ashouri, Amral; Scheler, Florian; Chiang, Yu-Hsien; Dubajic, Milos; Anaya Martín, Miguel; Stranks, Samuel D.; Universidad de Sevilla. Departamento de Física de la Materia Condensada; European Union (UE). H2020; Engineering Physical Sciences Research Council (EPSCR) U. K.
Microscopy provides a proxy for assessing the operation of perovskite solar cells, yet most works in the literature have focused on bare perovskite thin flms, missing charge transport and recombination losses present in full devices. Here we demonstrate a multimodal operando microscopy toolkit to measure and spatially correlate nanoscale charge transport losses, recombination losses and chemical composition. By applying this toolkit to the same scan areas of state-of-the-art, alloyed perovskite cells before and after extended operation, we show that devices with the highest macroscopic performance have the lowest initial performance spatial heterogeneity—a crucial link that is missed in conventional microscopy. We show that engineering stable interfaces is critical to achieving robust devices. Once the interfaces are stabilized, we show that compositional engineering to homogenize charge extraction and to minimize variations in local power conversion efciency is critical to improve performance and stability. We fnd that in our device space, perovskites can tolerate spatial disorder in chemistry, but not charge extraction.
Revisiting Stability Criteria in Ball-Milled High-Entropy Alloys: Do Hume–Rothery and Thermodynamic Rules Equally Apply?
(Willey, 2024-10-07) Blázquez Gámez, Javier Sebastián; Manchón Gordón, Alejandro F.; Vidal Crespo, Antonio; Caballero Flores, Rafael; Ipus Bados, Jhon Jairo; Conde Amiano, Clara Francisca; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Junta de Andalucía; Universidad de Sevilla
Stability descriptors for the formation of solid solutions can be divided into two categories: inspired by Hume–Rothery rules (HRR) and derived from thermodynamic approaches. Herein, HRRs are extended from binary to high-entropy alloys (HEAs) focusing on compositions prepared by ball milling. Parameters describing stability criteria are interrelated and implicitly account for the microstrains’ storage energy, more determinant than entropy increase in stabilization of HEAs and more effective in bcc structures than close-packed ones (fcc and hcp). An effective temperature, Teff, is defined as the ratio between increase in metallic bonding energy of solid solutions with respect to segregated pure constituents and configurational entropy. This versatile parameter is used as a threshold for stabilization of HEAs at equilibrium and out of equilibrium. When Teff is below room temperature, HEA would be stable at equilibrium. When Teff is below melting temperature, HEA would be obtained by rapid quenching. Limitations related to electronegativity differences remain valid in mechanically alloyed solid solutions. However, ball milling broadens the allowed differences in atomic size to form HEA. Moreover, thermodynamic criteria can be surpassed in these systems, allowing the formation of single-phase solid solutions beyond the compositional range predicted by those criteria.
Magnetostructural transformation and magnetocaloric response in Mn(Fe)NiSi(Al) alloys
(Elsevier, 2024-09-30) Khan, Aun N.; Moreno Ramírez, Luis Miguel; Law, Jia Yan; Franco García, Victorino; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España; Oficina de Investigación Científica de la Fuerza Aérea. EE. UU.; European Innovation Council. E. U,
An efficient magnetocaloric refrigerant must have certain characteristics such as a sharp transition near the desired working temperature, a large cyclic magnetocaloric response, and the use of raw materials with reduced costs and low environmental consequences. In this sense, this work focuses on a series of rare-earth- and Co-free Mn0.5Fe0.5NiSi1-xAlx alloys (x = 0.0525, 0.060, 0.0685) with promising magnetocaloric properties. The alloys were synthesized using combined arc melting and induction melting techniques, as this synthesis route provides improved control on the sample composition and homogeneity. We investigated how the heat treatment temperature and Al content affect the magnetostructural and magnetocaloric properties of the alloys. On the one hand, it is found that annealing at 1173 K for 7 days leads to a sharp magnetostructural transformation with no traces of impurities for the alloy with x = 0.0525. Under these conditions, a large isothermal entropy change of –11.5 J kg−1 K−1 for 1 T is obtained near room temperature, significantly improving the value of the as-cast sample. On the other hand, following this optimal heat treatment, the influence of Al content is studied: upon increasing the Al concentration the magnetostructural transformation shifts to lower temperatures, ranging from 320 K for x = 0.0525 to 220 K for x = 0.0685 (measured upon heating).
Interplay between connectivity and passivating agents in perovskite quantum dot networks
(Royal Society of Chemistry, 2024-10-02) Morán Pedroso, María; Tiede, David O.; Romero-Pérez, Carlos; Calvo, Mauricio E.; Galisteo López, Juan F.; Míguez, Hernán; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España; Unión Europea NextGeneration; Junta de Andalucía
Introducing quantum dots (QDs) as the active element of an optoelectronic device demands its incorporation in the shape of interconnected arrays that allow for some degree of electronic coupling in order to inject/extract charge carriers. In doing so, beyond reducing the degree of quantum confinement, carriers are exposed to an enhanced defect landscape as they can access adjacent QDs, which is at the origin of the strong reduction of photoluminescence observed in QD solids when compared to that of the isolated QDs. In this work we demonstrate how a proper defect passivating strategy or atmospheric treatment can greatly enhance charge diffusion in a QD film, needed for an optimal carrier injection/extraction demanded for optoelectronic applications, and also improved its stability against external radiation. From a fundamental perspective, we provide evidence showing that trap density distribution, rather than QD size distribution, is mostly responsible for the observed variations in emission decay rates present in the QD networks under analysis.
Influence of the chemical activation with KOH/KNO3 on the CO2 adsorption capacity of activated carbons from pyrolysis of cellulose
(Elsevier, 2024-10-07) Lamata Bermejo, Irene; Alba, María D.; Ramírez Rico, Joaquín; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Junta de Andalucía; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER)
Plant biomass is an attractive precursor to prepare activated carbons with high surface area for CO2 adsorption due to its low-cost and easy regeneration. Despite this interest, there are still remaining questions regarding the optimal processing conditions and the choice of activating agent. Moreover, since plant biomass shows a highly variable proportion of different biopolymers (cellulose, hemicellulose, lignin), it is important to understand the activation effect on each constituent. In this work, carbons obtained from pyrolysis of cellulose were activated using two potassium salts, using two different activation temperatures. The samples were characterized to elucidate the influence of the activation conditions on their CO2 adsorption capacity. In general, all the carbons activated at higher temperature showed higher adsorption capacity. These results are comparable with other carbons derived from biomass described in the bibliography. Among the activated carbons studied, the carbon activated only with KOH exhibits the highest CO2 adsorption capacity at 1 bar meanwhile the highest adsorption capacity at saturation pressure belongs to the carbon activated with larger ratio of KNO3.
Compositional Gradient of Mixed Halide 2D Perovskite Interface Boosts Outdoor Stability of Highly Efficient Perovskite Solar Cells
(Willey, 2023-12-23) Degani, Matteo; Pallotta, Riccardo; Pica, Giovanni; Karimipour, Masoud; Mirabelli, Alessandro; Frohna, Kyle; Anaya Martín, Miguel; Grancini, Giulia; Universidad de Sevilla. Departamento de Física de la Materia Condensada; European Research Council (ERC); European Union (UE). H2020; Engineering and Physical Sciences Research Council (UK)
Interface engineering using self-assembled 2D perovskite interfaces is a consolidated route to efficient and durable perovskite solar cells. Whether the 2D perovskite forms a homogeneous conformal layer or is heterogeneously distributed on the surface, interface defects are passivated, leading to a general improvement in the device's open circuit voltage (VOC) and stability. Here, an innovative strategy is developed for manipulating the composition of the 2D/3D perovskite interface that results in the formation of a gradient halide distribution, which extends from the surface to the bulk. The use of a bromide-based 2D perovskite triggers a progressive Br/I exchange, affecting not only the surface but also the perovskite underneath. As a result, not only the device VOC improve, as expected, but also the photogenerated current is boosted, leading to a device efficiency of up to 24.4%. Such mixed halide gradient effectively passivates surface and bulk defects making the perovskite active layer more efficient and robust, as demonstrated by the superior device stability showing zero losses in performances upon 36 days (more than 800 h) test in outdoor conditions, those ones relevant for a marketable product.
Better together: Monolithic halide perovskite@metal-organic framework composites
(Cell Press, 2024-12-04) Ávila, Elena; Salway, Hayden; Ruggeri, Edoardo; Çamur, Ceren; Rampal, Nakul; Doherty, Tiarnan A. S.; Moseley, Oliver D. I.; Stranks, Samuel D.; Fairen Jiménez, David; Anaya Martín, Miguel; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Agencia Estatal de Investigación. España
A few years ago, we theoretically studied the production of a stellar neutron spectrum at kT 30 keV using a shaped proton beam impinging on a thick lithium target. Here, we first measure the proton distribution to better control the produced neutron spectrum. Then, we measure the forward-emitted angle-integrated neutron spectrum of the 7Li(p,n)7Be reaction via time-of-flight neutron spectrometry with such proton distribution. The result resembles a stellar neutron spectrum at kT 30 keV. This method avoids in activation experiments the need for spectrum correction. In the case of spherical samples, no knowledge of the crosssection of the isotope being measured by activation would be necessary. Therefore, the present method is of interest for isotopes with unknown or poorly known cross-sections, such as branching points in astrophysics. The key point of our method is the experimental control of the proton distribution that impinges on the lithium target.
Thermomagnetic liquid metal switches with fast bidirectional response
(Springer Nature, 2025-03-17) Chen, Haodong; Xie, Yuyu; Qiao, Kaiming; Xie, Longlong; Yu, Ziyuan; Xu, Chenyu; Liu, Jingyi; Liu, Mingze; Lu, Yongyu; Law, Jia Yan; Franco García, Victorino; Zhang, Hu; Universidad de Sevilla. Departamento de Física de la Materia Condensada; National Natural Science Foundation of China; National Key Research and Development Program of China; State Key Laboratory for Advanced Metals and Materials; Agencia Estatal de Investigación. España; Junta de Andalucía
Traditional thermal switches usually suffer from long-time and unidirectional response. Herein, we combined liquid metals with magnetic Ni2Mn1.4In0.6 particles and developed a thermomagnetic liquid metal. These materials not only show excellent fluidity and electrical conductivity, but also exhibit fast response at a tuneable temperature that traditional magnetic liquid metals do not have. The ultimate application is designed as micro-channel thermal switch. Particularly, our thermal switch features bidirectional response through the droplet displacement, thus simultaneously cutting off the working circuit while turning on the fire extinguishing. Its response time of 1.2 s is 3.3 − 5.6 times faster than typical commercial thermal switches under the same hot source temperature of 75 °C, and it can be further reduced to 660 ms under the optimal environment. Moreover, this fast-response thermal switch offers the fastest recovery time, low cost, and long-cycle stability, showing a huge potential as a generation of thermal switches for diverse applications.
What preset time schedule will it be? Rethinking daylight saving time
(Sage Journals, 2025-03-26) Martín Olalla, José María; Jorge Mira; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Universidad de Sevilla. FQM130: Propiedades Térmicas y Dieléctricas de Solidos
We discuss the foundations of the seasonal clock policy in view of a recent review article.
Assessing the best hour to start the day: an appraisal of seasonal Daylight Saving Time
(The Royal Society, 2025-03-19) Martín Olalla, José María; Mira, Jorge; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Universidad de Sevilla. FQM130: Propiedades Térmicas y Dieléctricas de Solidos
We provide an evidence-based position on the seasonal regulation of clocks (Daylight Saving Time, DST) that challenges position papers by sleep associations against the practice. We review the acute, short-term impact and the chronic, long-term impact of DST in the context of the changing ambient light conditions that characterize seasons at Extratropical latitudes. We highlight the association between DST, human physiology (photoreceptive mechanisms), and human daily life. We offer a perspective on the possible scenarios should clock regulations be abandoned.
Trapping of Gas Bubbles in Water at a Finite Distance below a Water-Solid Interface
(American Chemical Society, 2019-03-01) Esteso Carrizo, Victoria; Carretero-Palacios, S.; Thiyam, P.; Míguez, H.; Parsons, D. F.; Brevik, I.; Boström, M.; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Research Council. Norway; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Agencia Estatal de Investigación. España
Gas bubbles in a water-filled cavity move upward because of buoyancy. Near the roof, additional forces come into play, such as Lifshitz, double layer, and hydrodynamic forces. Below uncharged metallic surfaces, repulsive Lifshitz forces combined with buoyancy forces provide a way to trap micrometer-sized bubbles. We demonstrate how bubbles of this size can be stably trapped at experimentally accessible distances, the distances being tunable with the surface material. By contrast, large bubbles (≥100 μm) are usually pushed toward the roof by buoyancy forces and adhere to the surface. Gas bubbles with radii ranging from 1 to 10 μm can be trapped at equilibrium distances from 190 to 35 nm. As a model for rock, sand grains, and biosurfaces, we consider dielectric materials such as silica and polystyrene, whereas aluminium, gold, and silver are the examples of metal surfaces. Finally, we demonstrate that the presence of surface charges further strengthens the trapping by inducing ion adsorption forces.
Natural abundance 17 O MAS NMR and DFT simulations: New insights into the atomic structure of designed micas
(Elsevier, 2019-08) Pavón González, Esperanza; Osuna, Francisco J.; Alba Carranza, María Dolores; Delevoye, Laurent; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Université de Lille; Junta de Andalucía; Agencia Estatal de Investigación. España
Combining 17 O Magic-Angle Spinning (MAS) NMR at natural abundance with DFT calculations is a promising methodology to shed light on the structure and disorder in tetrahedral sheets of designed micas with enhanced properties. Among brittle micas, synthetic mica is an important alternative to natural ones with a swelling sheet-like structure that results in many applications, by exploiting unique characteristics. Lowenstein's rule is one of the main chemical factor that determines the atomic structure of aluminosilicates and furthermore their properties. In the present article, 17 O MAS NMR spectroscopy is used to validate (or not) the agreement of the Lowenstein's rule with the distribution of Si and Al sites in the tetrahedral sheets of synthetic micas. 17 O MAS spectra of synthetic high-charged micas exhibit two regions of signals that revealed two distinguishable oxygen environments, namely Si-O-X (with X = Si, Al tet , Mg) and Al tet -O-Y (Y=Mg or Al tet ). DFT calculations were also conducted to obtain the 17 O chemical shift and other NMR features like the quadrupolar coupling constant, C Q , for all of the oxygen environments encountered in the two model structures, one respecting the Lowenstein's rule and the other involving Al tet -O-Al tet and Si-O-Si environments. Our DFT calculations support the 17 O assignment, by confirming that Al tet -O-3Mg and Al tet -O-Al tet oxygen environments show chemical shifts under 30 ppm and more important, with quadrupolar coupling constants of about 1 MHz, in line with the spectral observation. By quantifying the 17 O MAS NMR spectra at natural abundance, we demonstrate that one of the synthetic mica compositions does not meet the Lowenstein's rule.
Perspectives and Energy Applications of Magnetocaloric, Pyromagnetic, Electrocaloric, and Pyroelectric Materials
(Wiley, 2024-08-30) Klinar, K; Law, Jia Yan; Franco García, Victorino; Moya, X; Kitanovski, A; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Agencia de Investigación e Innovación de Eslovenia; Oficina de Investigación Científica de la Fuerza Aérea; European Union (UE)
This perspective provides an overview of the state of research and innovation in the areas of magnetocaloric and pyromagnetic materials, and electrocaloric and pyroelectric materials, including the overlapping sub-areas of multicaloric and multipyro materials that can operate simultaneously under the application of magnetic and electric fields. These materials are critically examined for their potential to revolutionize cooling, heating, and energy-harvesting applications. This perspective first summarizes the state-of-the-art advancements and highlights recent significant developments. Then, it is identified and discussed that the prevailing challenges hindering the widespread adoption of technologies based on these materials. In this context, after consulting with members of the caloric and pyro communities, a technology roadmap is outlined to guide research efforts in overcoming current barriers to applications, with the goal of achieving impactful results by 2040. This roadmap emphasizes the importance of focusing on under-researched materials, novel devices, and application spaces, paving the way for interdisciplinary efforts that can lead to significant reductions in carbon dioxide emissions.
Long-Term Impacts of Intense Pulsed Light Therapy on Ocular Surface Health and Tear Film Dynamics in Patients with Dry Eye Disease: Detailed Analysis and Observations Over a 1-Year Follow-Up Period
(Springer, 2024-08-16) Pac, Cristina Patricia; Munteanu, Mihnea; Sánchez González, José María; Rocha de Lossada, Carlos; Mercea, Nadina; Ferrari, Francis; Blidisel, Alexandru; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Universidad de Sevilla. Departamento de Cirugía
To evaluate the long‑term effects of intense pulsed light (IPL) therapy on patients with dry eye disease (DED) associated with mei‑ bomian gland dysfunction (MGD). Methods: A retrospective case series was per‑ formed with 110 participants undergoing IPL therapy. Assessments included the eye fitness test (EFT) to gauge subjective symptoms, along with objective measures using the Tearcheck ® device (ESW Vision, Houdan, France) noninva‑ sive first breakup time (NIFBUT), noninvasive average breakup time (NIABUT), central tear meniscus height (CTMH), thinnest tear menis‑ cus height (TTMH), and ocular surface inflam‑ matory risk evaluation (OSIE) assessed using the SCHWIND SIRIUS device (SCHWIND eye‑tech‑ solutions GmbH, Kleinostheim, Germany). Results: This study documented significant improvements in subjective and objective
Influence of the atmosphere on the formation of high-entropy oxides within the Co–Cu–Fe–Mg–Mn–Ni–O system via reactive flash sintering
(Elsevier, 2024-08-05) Manchón Gordon, Alejandro Fernando; Lobo-Llamas, C.; Molina Molina, Sandra; Perejón Pazo, Antonio; Sánchez-Jiménez, P. E.; Pérez-Maqueda, L. A.; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Universidad de Sevilla. Departamento de Química Inorgánica; Junta de Andalucía; Ministerio de Ciencia e Innovación (MICIN). España; European Union (UE)
In this study, the feasibility of preparing quinary equimolar high-entropy oxides within the Co–Cu–Fe–Mg–Mn–Ni–O system was explored using the reactive flash sintering (RFS) technique. Various compositions were tested using this technique under atmosphere pressure, leading to the formation of two primary phases: rock-salt and spinel. Conversely, a new high-entropy oxide was produced as a single-phase material with the composition (Co0.2,Cu0.2,Mg0.2,Mn0.2,Ni0.2)O when RFS experiments were conducted in nitrogen atmosphere. The reducing conditions achieved in nitrogen enabled the incorporation of cations with oxidation states different from +2 into the rock-salt lattice, emphasizing the critical role of the processing atmosphere, whether inert or oxidizing, in the formation of high-entropy oxides. The electrical characterization of this material was obtained via impedance spectroscopy, exhibiting a homogeneous response attributed to electronic conduction with a temperature dependence characteristic of disordered systems.
A zirconia/tantalum biocermet: in vitro and in vivo evaluation for biomedical implant applications
(Royal Society of Chemistry, 2024-08-05) Smirnov, A. I.; Guitián, F; Ramírez Rico, Joaquín; Bartolomé, J. F.; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Russian Science Foundation
A biocermet made of zirconia/20 vol% tantalum (3Y-TZP/Ta) is a new composite with exceptional capabilities due to a combination of properties that are rarely achieved in conventional materials (high strength and toughness, cyclic fatigue resistance and flaw tolerance, wear resistance, corrosion resistance, electrical conductivity, etc.). In this study, for the first time, the biomedical performance of a 3Y-TZP/Ta biocermet was evaluated in detail. Its in vitro biocompatibility was assessed using mesenchymal stem cell culture. The effectiveness of in vivo osteointegration of the biocermet was confirmed 6 months after implantation into the proximal tibiae of New Zealand white rabbits. In addition, the possibility of using magnetic resonance imaging (MRI) for medical analysis of the considered biocermet material was studied. The 3Y-TZP/Ta composite showed no injurious effect on cell morphology, extracellular matrix production or cell proliferation. Moreover, the implanted biocermet appeared to be capable of promoting bone growth without adverse reactions. On the other hand, this biocermet demonstrates artefact-free performance in MRI biomedical image analysis studies, making it more suitable for implant applications. These findings open up possibilities for a wide range of applications of these materials in orthopedics, dentistry and other areas such as replacement of hard tissues.
Self-reported preferences for seasonal daylight saving time meet fundamentals of human physiology: Correlations in the 2018 public consultation by the European Commission
(Taylor & Francis, 2025-01-27) Martín Olalla, José María; Mira, Jorge; Universidad de Sevilla. Departamento de Física de la Materia Condensada
We analyze the results to question 2 (individual preferences for cancelling or keeping the current clock regulations) from the 2018 Public Consultation on summertime arrangements (DST) conducted by the European Commission. We reveal correlations in the shares of population for cancelling the regulations and the winter sunrise time (SRW) [R2 = 0.177; p = 0.03; N = 25] and the onset of human activity [R2 = 0.677; p = 5 × 10−5; N = 17]. The results are in line with the rationale behind the regulations in the range of latitude 35 to 63: larger values of SRW (larger latitude) brought larger shares against the regulations; and earlier onset of human activity relative to SRW brought larger shares against the regulations. The shares for cancelling the regulation did not show correlations with time offset (position in time zone), thus challenging the current view within the circadian community.
Phase dependence of the thermal memory effect in polycrystalline ribbon and bulk Ni55Fe19Ga26 Heusler alloys
(Elsevier, 2025-02-09) Vidal Crespo, Antonio; Manchón-Gordón, Alejandro F.; Martín Olalla, José María; Romero Landa, Francisco Javier; Ipus Bados, Jhon Jairo; Gallardo Cruz, María del Carmen; Blázquez Gámez, Javier Sebastián; Conde Amiano, Clara Francisca; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Junta de Andalucía
The thermal memory effect, TME, has been studied in Ni55Fe19Ga26 shape memory alloys, fabricated as ribbons via melt-spinning and as pellets via arc-melting, to evaluate its dependence on the martensitic structure and the macrostructure of the samples. When the reverse martensitic transformation is interrupted, a kinetic delay in the subsequent complete transformation is only evident in the ribbon samples, where the 14M modulated structure is the dominant phase. In contrast, degradation of the modulated structure or the presence of the phase significantly reduces the observed TME. In such cases, the magnitude of the TME approaches the detection limits of commercial calorimeters, and only high-resolution calorimeter at very low heating rate (40 mK h−1) can show the effect. Following the kinetic arrest and subsequent cooling, the reverse martensitic transformation was completed at several heating rates to confirm the athermal nature of the phenomenon.
Efficacy assessment of liposome crosslinked hyaluronic acid and standard hyaluronic acid eye drops for dry eye disease management: a comparative study employing the ocular surface analyzer and subjective questionnaires
(Frontiers Media S.A., 2024-06-26) Sánchez González, José María; Hita Cantalejo, María Concepción de; González Rodríguez, María Luisa; Fernández-Trueba-Fagúndez, Ana; Ballesteros-Sánchez, Antonio; Martínez-Pérez, Clara; Caro-Díaz, Romina; Montiel Guzmán, Carla; González-Oyarce, María Fernanda; Sánchez González, María del Carmen; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Universidad de Sevilla. Departamento de Farmacia y Tecnología Farmacéutica
Introduction: Dry eye disease (DED) is a prevalent condition causing ocular discomfort and visual disturbances, often managed with artificial tears. This study aimed to assess and compare the efficacy of eye drops containing Crosslinked Hyaluronic Acid (CHA) with liposomes and crocin and standard Hyaluronic Acid (HA) for DED management. Methods: A single-blind, longitudinal study was conducted on 24 participants (48 eyes), randomized to receive one of the two treatments. Ocular health measures, including the ocular surface disease index (OSDI) and the standard patient evaluation of eye dryness (SPEED) scores, were assessed at baseline and 6 weeks post-treatment using the Ocular Surface Analyzer. Results: CHA achieved a lipid layer thickness increase of 1.29 ± 1.08 Guillon pattern degree (p < 0.01), FNIBUT increase 0.64 ± 0.77 s (p < 0.01), MNIBUT increase1.28 ± 4.74 s (p = 0.19), OSDI decrease 11.72 ± 6.73 score points (p < 0.01) and SPEED decrease 1.16 ± 5.05 score points (p = 0.27). Significant reductions in the OSDI and SPEED scores post-treatment were observed with both treatments, indicating their effectiveness. Conclusion: CHA with liposomes exhibits superior efficacy compared to standard HA eye drops in the management of DED. These findings highlight the potential for personalized treatment strategies incorporating CHA, indicating a more effective approach to DED management. However, further research is required to validate these results and investigate the long-term effects, which may pave the way for a data-driven and optimized approach to managing DED.
Processability and Properties of Cubic-BaTiO 3/poly(vinylidene fluoride) Composites for Additivemanufacturing: From Powder Compoundingto 3D-printed Parts
(John Wiley & Sons, 2024) Moriche Tirado, Rocío; Donate, R.; Otero Pino, Andrea; Santiago Andrades, L.; Monzón, E.; Sayagués, M. J.; Monzón, M.; Paz, R.; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Ministerio de Ciencia e Innovación (MICIN). España; European Union (UE)
Poly(vinylidene fluoride) (PVDF) is a piezoelectric and thermoplastic material with great potential for additive manufacturing (AM) applications. Using barium titanate (BaTiO3) as filler, PVDF-based composite materials were developed, characterized, and processed by AM material extrusion (MEX). The morphological features and phase transformations occurring throughout the processing of BaTiO3-filled PVDF, from the compounding to the printed part, were analyzed. The morphology of the powder feedstock after dispersion in a high-energy ball mill changed from spheroidal to laminar and β-phase formation was favored. Microhardness gradually increased with the BaTiO3 content, obtaining an enhancement of ~60% for a content of 25 vol%, and supported the good dispersion of the filler. A ~48% increase of the dielectric permittivity was also achieved. After extrusion, filaments with a filler content of 15 vol% showed a more stable diameter, as well as higher crystallinity and surface roughness, compared with those with lower BaTiO3 contents. Material extrusion of filament and direct printing of pellets based on MEX were successfully used to obtain AM parts. Composite parts showed enhanced surface roughness, hydrophilicity, and flexural modulus (up to ~33% for the 7 vol% composite compared with the PVDF), thus leading to superior mechanical characteristics and potential biomedical applications. Highlights: Dry high-energy ball milling was a suitable greener dispersion approach. MEX processes were successfully used to obtain 3D-printed parts. The use of direct printing of pellets/powder improved the 3D printability. The surface roughness and hydrophilicity increased with the filler content. The permittivity and elastic modulus increased with the filler content.

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