Articles publicats en revistes (Enginyeria Electrònica i Biomèdica)

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Sociodemographic, clinical, and immunological factors associated with SARS-CoV-2 diagnosis and severe COVID-19 outcomes in people living with HIV: a retrospective cohort study.
(Elsevier B.V., 2021-10-13) Cortés, C.; Force, L.; Letang, Emilio; Vilaró, I.; Casabona, J.; Miró Meda, José M. (José María), 1956-; PISCIS study group.; Nomah, D.K.; Reyes-Urueña, J.; Díaz, Y.; Moreno, Silvia; Aceiton, J.; Bruguera, A.; Vivanco-Hidalgo, R.M.; Llibre, J.M.; Domingo, Pere (Domingo Pedrol); Falcó, V.; Imaz, Arkaitz
Background: Factors affecting outcomes of SARS-CoV-2 infection in people living with HIV are unclear. We assessed the factors associated with SARS-CoV-2 diagnosis and severe outcomes among people living with HIV. Methods: We did a retrospective cohort study using data from the PISCIS cohort of people with HIV in Catalonia (Spain) between March 1 and Dec 15, 2020. We linked PISCIS data with integrated health-care, clinical, and surveillance registries through the Public Data Analysis for Health Research and Innovation Program of Catalonia (PADRIS) to obtain data on SARS-CoV-2 diagnosis, chronic comorbidities, as well as clinical and mortality outcomes. Participants were aged at least 16 years in care at 16 hospitals in Catalonia. Factors associated with SARS-CoV-2 diagnoses and severe outcomes were assessed using univariable and multivariable Cox regression models. We estimated the effect of immunosuppression on severe outcomes (hospital admission for >24 h with dyspnoea, tachypnoea, hypoxaemia, asphyxia, or hyperventilation; or death) using Kaplan-Meier survival analysis. Findings: We linked 20 847 (72·8%) of 28 666 participants in the PISCIS cohort with PADRIS data; 13 142 people had HIV. 749 (5·7%) people with HIV were diagnosed with SARS-CoV-2: their median age was 43·5 years (IQR 37·0-52·7), 131 (17·5%) were female, and 618 (82·5%) were male. 103 people with HIV (13·8%) were hospitalised, seven (0·9%) admitted to intensive care, and 13 (1·7%) died. SARS-CoV-2 diagnosis was more common among migrants (adjusted hazard ratio 1·55, 95% CI 1·31-1·83), men who have sex with men (1·42, 1·09-1·86), and those with four or more chronic comorbidities (1·46, 1·09-1·97). Age at least 75 years (5·2, 1·8-15·3), non-Spanish origin (2·1, 1·3-3·4), and neuropsychiatric (1·69, 1·07-2·69), autoimmune disease (1·92, 1·14-3·23), respiratory disease (1·84, 1·09-3·09), and metabolic disease (2·59, 1·59-4·23) chronic comorbidities were associated with increased risk of severe outcomes. A Kaplan-Meier estimator showed differences in the risk of severe outcomes according to CD4 cell count in patients with detectable HIV RNA (p=0·039) but no differences were observed in patients with undetectable HIV RNA (p=0·15). Interpretation: People living with HIV with detectable HIV viraemia, chronic comorbidities, and some subpopulations could be at increased risk of severe outcomes from COVID-19. These groups should be prioritised in clinical management and SARS-CoV-2 vaccination programmes. Funding: Fundació "la Caixa". Translations: For the Catalan, Spanish and Russian translations of the Summary see Supplementary Materials section.
Low Gain Avalanche Detectors for 4-dimensional Tracking Applications in Severe Radiation Environments
(Physical Society of Japan, 2021-06-10) Alonso Casanovas, Oscar; Diéguez Barrientos, Àngel; RD50 Collaboration
For the High Luminosity upgrade of the CERN Large Hadron Collider (HL-LHC), the collider will reach a peak instantaneous luminosity of 5 × 1034 cm−2 s−1, with a total integrated luminosity of ∼3000 fb−1 after around 12 years of expected lifetime. The pile-up during the p+p+ collisions is expected to reach values of ∼200 and the experiments are expected to be exposed to radiation levels up to 1.6 × 1016 neq cm−2 at the innermost layers of the detectors. Moreover, in future proposal colliders, like for example FCC-hh, the pile-up is expected to be a factor of five higher while the radiation levels will increase by a factor of ten with respect to the HL-LHC. Under this scenario, in the framework of ATLAS, CMS, RD50 and other sensor R&D projects, radiation tolerant silicon sensors for timing and tracking applications are being developed. Giving the expected radiation levels and the demanding spatial resolution plus timing capabilities required, one important line of research is focused on silicon sensors with intrinsic charge gain: Low Gain Avalanche Detectors (LGADs). This paper aims to give an overview of the current status of this technology. The most interesting approaches for future 4-dimensional tracking applications based on the LGAD technology will be presented here. In addition, the latest results on the performance after irradiation of standard LGADs will be reviewed too.
Latest Depleted CMOS Sensor Developments in the CERN RD50 Collaboration
(Physical Society of Japan, 2021-06-10) Alonso Casanovas, Oscar; Diéguez Barrientos, Àngel; CERN RD50 Collaboration
This contribution summarizes the most recent activities carried out within the CERN RD50 collaboration with regard to Depleted Monolithic Active Pixel Sensors (DMAPS). In particular, these activities have been focused on the characterization of the RD50-MPW2 prototype. RD50-MPW2 is the second DMAPS prototype developed in the 150 nm HV-CMOS technology process from LFoundry. The main characteristics of the RD50-MPW2 design will be reviewed. The leakage current, breakdown voltage and Edge Transient Current Technique (E-TCT) measurements of the RD50-MPW2 test structures will be presented. The characterization of the RD50-MPW2 active matrix and its readout electronics will be also described. Finally, the initial characteristics of the new RD50-MPW3 DMAP sensor prototype being designed at present by the CERN-RD50 collaboration will be shown.
Operational Experience and Performance of the Belle II Pixel Detector
(Physical Society of Japan, 2021-06-10) Liu, Qi; Abudien, F.; Ackermann, K.; Ahlbufg, P.; Albalawi, M.; Alonso Casanovas, Oscar; Diéguez Barrientos, Àngel; Belle II VTX Collaboration
The Belle II experiment at the super KEK B factory (SuperKEKB) started its physics operation with the full detector setup in March 2019, and it aims at collecting 50 ab−1 of e+e− collision data. The vertex detector (VXD) of Belle II contains a 4-layer silicon vertex detector (SVD) using double sided silicon strips and an inner 2-layer pixel detector (PXD) that is based on the depleted P-channel Field Effect Transistor (DEPFET) technology. The signal generation and amplification are combined in pixels with a minimum pitch of 55 × 50 µm2. The sensors are thinned down to 75 µm, and each module has interconnects and ASICs integrated on the sensor with silicon frames for mechanical support. This approach led to a material budget of around 0.21% X0 per layer including the cooling structure in the acceptance region. The PXD has an integration time of around 20 µs, a signal-to-noise ratio of around 50 and a detecting efficiency of better than 99%. Its two layers are arranged at the radii of 14 and 22 mm around the interaction point, and an impact parameter resolution of better than 15 µm has been achieved. Due to its close proximity to the beam line and its sensitivity to few-keV photons, the PXD also plays an important role in background studies.
Compatibility Study of 3D Printing and PCB Technologies for RF Components and Circuits
(Wiley, 2025-08-01) López Villegas, José María; Vidal Martínez, Neus
This paper explores the potential of combining additive manufacturing with printed circuit board technology to fabricate radio frequency components and circuits. This combination aims to leverage the design freedom of additive manufacturing to implement very compact, high‐quality components, while capitalizing on the established processes and design knowledge associated with printed circuit board manufacturing of radio frequency circuits. The idea behind this technological combination is not just to incorporate 3D‐printed parts
onto the printed circuit board, as usual, but go a step forward and embed these components as parts of the board itself. By doing so, we aim to improve the compactness, electrical connectivity and mechanical stability of the entire system. As a test component for our study, we chose a helical‐microstrip transmission line segment. Due to the 3D nature of this type of transmission line, large values of electrical length can be obtained with short segments, making them very useful in the design of compact radio frequency components. We propose a new procedure for embedding this 3D structure into a printed circuit board substrate while considering electrical connectivity and mechanical stability during the different steps of the process. To demonstrate the functionality of our proposed method in the design of more complex structures, two embedded helical‐microstrip transmission line segments are combined to form a compact 2‐way Wilkinson power divider/combiner suitable for operation in the radio frequency band of a few hundreds MHz.
CMOS MAPS upgrade for the Belle II Vertex Detector
(Elsevier B.V., 2023-01-02) Babeluk, M.; Alonso Casanovas, Oscar; Diéguez Barrientos, Àngel; Belle II VTX Collaboration
The success of the Belle II experiment in Japan relies on the very high instantaneous luminosity, close to 6x10^35 cm^-2 s^-1, expected from the SuperKEKB collider. The corresponding beam conditions at such luminosity levels generate large rates of background particles and creates stringent constraints on the vertex detector, adding to the physics requirements. Current prospects for the occupancy rates in the present vertex detector (VXD) at full luminosity fall close to the acceptable limits and bear large uncertainties. In this context, the Belle II collaboration is considering the possibility to install an upgraded VXD system around 2027 to provide a sufficient safety margin with respect to the expected background rate and possibly enhance tracking and vertexing performance. The VTX collaboration has started the design of a fully pixelated VXD, called VTX, based on fast and highly granular Depleted Monolithic Active Pixel Sensors (DMAPS) integrated on light support structures. The two main technical features of the VTX proposal are the usage of a single sensor type over all the layers of the system and the overall material budget below 2% of radiation length, compared to the current VXD which has two different sensor technologies and about 3% of radiation length. A dedicated sensor (OBELIX), taylored to the specific needs of Belle II, is under development, evolving from the existing TJ-Monopix2 sensor. The time-stamping precision below 100 ns will allow all VTX layers to take part in the track finding strategy contrary to the current situation. The first two detection layers are designed according to a self-supported all-silicon ladder concept, where 4 contiguous sensors are diced out of a wafer, thinned and interconnected with post-processed redistribution layers. The outermost detection layers follow a more conventional approach with a cold plate and carbon fibre support structure, and light flex cables interconnecting the sensors. This document will review the context, technical details and development status of the proposed Belle II VTX.
Malaria quantitative POC testing using magnetic particles, a paper microfluidic device and a hand-held fluorescence reader
(Elsevier B.V., 2022-11-01) Arias Alpízar, Kevin; Sánchez-Cano, A.; Prat-Trunas, J.; Serna, E.; Alonso Casanovas, Oscar; Sulleiro, E.; Sánchez-Montalvá, Adrián; Diéguez Barrientos, Àngel; Baldrich, E.
A point-of-care (POC) device is reported for highly sensitive and selective detection of Plasmodium falciparum lactate dehydrogenase (Pf-LDH), a biomarker of malaria infection, based on a single-step magneto-immunoassay, a single-use microfluidic paper device and a customized hand-held fluorescence reader. The single-step magneto-immunoassay consists in a single 5-min incubation of immuno-modified magnetic particles (c-MAb-MPs), biotinylated detection antibody (bd-MAb), and an enzymatic signal amplifier (Poly-HRP). After on-chip MP concentration and washing, signal generation is achieved by adding a fluorescent enzymatic substrate (QuantaRed). Fluorescence signal is measured using a low-cost customized, portable, and sensible fluorescent detector. The POC affords quantitative Pf-LDH detection in <20 min, with a detection limit of 0.92 ng mL−1 (equivalent to 4.6 parasites μL−1). Furthermore, Pf-LDH quantitation in clinical samples correlates with that provided by the reference ELISA, is more sensitive than a commercial rapid diagnostic test (RDT) and entails little user intervention. These results show that fluorescent paper-based microfluidic devices can be exploited to simplify magneto-immunoassay handling, taking this type of test closer to the requirements of POC testing.
LoRa Power Model for Energy Optimization in IoT Applications
(MDPI, 2026-01-02) Soler-Fernández, Juan Luis; Romera, Omar; Diéguez Barrientos, Àngel; Prades García, Juan Daniel; Alonso Casanovas, Oscar
Energy efficiency is a key requirement for Internet of Things (IoT) nodes, particularly in applications powered by energy harvesting that operate without batteries. In this work, we present a parametric power model of a LoRa transceiver (Semtech SX1276) aimed at ultra-low power remote sensing scenarios. The transceiver was characterized in all relevant states (startup, transmission, reception, and sleep), and the results were used to build a state-based model that predicts average power consumption as a function of transmission power, sleep strategy, packetization, and input data rate. Experimental validation confirmed that the cubic fit for transmission peaks achieves a determination coefficient of 0.99, while reception is added as a constant consumption. The model was implemented in a Python simulator that provides mean, best-case, and worst-case estimates of system power consumption, and it was validated in an ASIC-based sensor node demonstration, with predictions within 10% of measured values. The framework highlights the trade-offs between energy efficiency and robustness (e.g., minimal SF and no CRC vs. higher spreading factors and error-control) and supports the design of custom controllers for ultra-low power IoT nodes as well as more energy-permissive applications.
ICAM-1 Targeting of Nanocarriers in a Human Blood-Brain-Barrier-on-a-Chip Complements In Vivo Brain Delivery Observations
(Taylor & Francis, 2025-12-18) Vigo, Marco; Palma Florez, Sujey; Grimalt-Mirada, Rita; Placci, Marina; Crespo, Andrés; Giannotti, Marina Inés; Lagunas Targarona, Anna; Mir Llorente, Mònica; Samitier i Martí, Josep; Muro, Silvia
Targeting therapeutic nanocarriers (NCs) to endothelial receptors favours transport across the blood-brain barrier (BBB), a main obstacle to access the brain. While these strategies compel validation in animals, quantitative sub-cellular resolution is non-viable in vivo. BBB-on-chip (BBB-oC) devices can help. Illustrating this, we used a BBB-oC comprising a lateral channel containing a human brain endothelial lining and a central chamber containing hydrogel-embedded pericytes and astrocytes. We studied NCs targeting intercellular adhesion molecule-1 (ICAM-1), a cell-surface protein overexpressed in pathology and involved in CAM-mediated transport. Brain access was validated in vivo after injection of NCs coated with anti-ICAM-1 vs. control IgG. ICAM-1 expression was verified in vitro using endothelial cells, pericytes, and astrocytes (756-, 511-, 690-fold over non-specific signal under TNFα). VE-cadherin presence and lack of dextran leakage demonstrated a restrictive BBB-oC barrier. Data showed endothelial targeting of anti-ICAM-1 NCs (428 NCs/cell at 1 h), uptake (60% of cell-interacting NCs), and transcytosis (90%; 24 h) downregulated by a CAM-pathway inhibitor (88% decay; 1 h). Non-transcyosed NCs trafficked to lysosomes, while transcytosed NCs interacted with pericytes and astrocytes (2643 NCs/cell; 24 h) and entered them (90% of transcytosed NCs). This BBB-oC represents a valuable model to evaluate ICAM-1-mediated transcytosis, complementing animal studies.
Operational experience of the Belle II pixel detector
(Elsevier B.V., 2022-06-01) Wang, B.; Alonso Casanovas, Oscar; Diéguez Barrientos, Àngel; Belle-II DEPFET and PXD Collaboration
The Belle II experiment at the SuperKEKB accelerator has started its physics data taking with the full detector setup in March 2019. It aims to collect 40 times more collision data compared with its predecessor Belle experiment. The Belle II pixel detector (PXD) is based on the Depleted P-channel Field Effect Transistor (DEPFET) technology. The PXD plays an important role in the tracking and vertexing of the Belle II detector. Its two layers are arranged at radii of 14 mm and 22 mm around the interaction point. The sensors are thinned down to 75 m to minimize multiple scattering, and each module has interconnects and ASICs integrated on the sensor with silicon frames for mechanical support. PXD showed good performance during data taking. It also faces several operational challenges due to the high background level from the SuperKEKB accelerator, such as the damage from beam loss events, the drift in the HV working point due to radiation effect, and the impact of the high background.
Belle II Vertex Detector: Run Performance (PXD + SVD) and Upgrade Developments (VTX)
(Scuola Internazionale Superiore di Studi Avanzati (SISSA), 2025-11-12) Dhayal, R.; Alonso Casanovas, Oscar; Diéguez Barrientos, Àngel; Belle II VTX Collaboration
TheBelle II experiment at SuperKEKB continues to pursue high-precision measurements in Standard Model studies and in searches for physics beyond the Standard Model, with a target dataset of 50 ab−1 and peak luminosities of 6×1035 cm−2s−1. The current Vertex Detector (VXD), composed of the DEpleted P-channel Field Effect Transistor (DEPFET)-based Pixel Detector (PXD) and double-sided strip-based Silicon Vertex Detector (SVD), has achieved excellent tracking and vertexing performance through Run 1 and Run 2. To address future challenges from increased luminosity and background, anewall-pixel VertexDetector (VTX)isunderdevelopment, utilizing radiation-hard DMAPS technology based on the OBELIX sensor. In this contribution, we present the performance of the current VXD system, highlight operational challenges, and present the validation and integration status of the upcoming VTX upgrade.
Commissioning of the Belle II Pixel Vertex Detector
(Scuola Internazionale Superiore di Studi Avanzati (SISSA), 2020-11-12) Ye, Hua; Alonso Casanovas, Oscar; Diéguez Barrientos, Àngel; On behalf the Belle II DEPFET and PXD Collaboration
As an upgrade of the asymmetric e+e collider KEKB, SuperKEKB aims to increase the peak luminosity by a factor of 40 to 8 1035 cm 2s 1. Theupgraded Belle II detector allows the experiment to handle the much increased data rates, with the goal to explore new physics beyond the Standard Model at the intensity frontier. Belle II is expected to accumulate a dataset of 50 ab 1 by 2027. The Belle II pixel detector (PXD) has been developed using the DEpleted P-channel Field Effect Transistor (DEPFET) technology, which combines low power consumption in the active pixel area and low intrinsic noise with a very small material budget. In this proceedings, commissioning and performance of this novel detector measured with first collision data are presented.
Multi-compartmentalized electrochemical sensing platforms for monitoring cascade enzymatic reactions
(Elsevier B.V., 2024-06-28) Fernández, Laia L.; Bastos-Arrieta, Julio; Appelhans, Dietmar; Zhou, Yang; Moreno, Silvia; Palet, Cristina; Baeza, Mireia
Designing an electrochemical biosensor with the required features is a complex process involving multiple factors. For instance, nanocomposite materials used ensure the adaptation of the sensor to specific parameters on demand. But beyond making more versatile sensors, these materials likely offer excellent sensing platforms to mimic biological processes (e.g. cell communication) on the electrode surface. For this, developed methods are needed to integrate non-conductive nanoreactors for molecular communication into a biocompatible matrix on electrode surfaces with the request of spatially separated and controlled enzyme localization. Here, we present a novel reduced graphene oxide hybrid material to immobilize polymeric nanoreactors supported by an alginate network as a matrix on the electrode surface. The possibility of introducing cascade reactions in an electrochemical biosensor has the advantage of broadening the target substrates as well as their selectivity using enzymes in different nanocompartments (=compartmentalization). The polymeric vesicles allow the loading of enzymes or artificial enzymes, offering active center retention and long-term enzyme stability. Firstly, the inclusion of spatially separated polymeric active nanocompartments into the matrix on the electrode surface is used to monitor a simple enzyme reaction. However, the study’s accomplishment lies in its successful ability to monitor an enzyme cascade reaction, one producing and the other consuming hydrogen peroxide, hosting natural and artificial enzymes. This proof-of-concept generates an important contribution to the design of analytical platforms capable of detecting complex environments or even monitoring communication between cell-like structures, extremely useful for fields such as synthetic biology, biomimetics and advanced biosensors.
Reading QR Codes on challenging surfaces using thin-plate splines
(Elsevier B.V., 2024-06-07) Benito Altamirano, Ismael; Martínez Carpena, David; Lizarzaburu-Aguilar, Hanna; Fàbrega Gallego, Cristian; Prades García, Juan Daniel
In real world uses, QR Codes are printed or overlaid on top of complex surfaces, like cylindrical bottles or other daily objects with random topographies that pose big challenges to their readout with the conventional planar algorithms proposed in the standard ISO and implemented in most of the available codes. We propose here a general-purpose method to improve the readability of QR Codes placed on these challenging surfaces, by fitting the topography of the underlying arbitrary surface with thin-plate splines. Then, we compare this new method with other alternatives proposed in the literature, like affine, projective and cylindrical transformations. Results demonstrate that our new approach works well under a variety of arbitrary surface topographies including those assumed in former proposals, and improve their readability by a factor of 4, clearly outperforming state-of-the-art decoders.
Design, Additive Manufacturing, and Characterization of a Symmetric 3-Way Wilkinson Power Divider/Combiner
(IEEE, 2025-11-08) López Villegas, José María; Vidal Martínez, Neus
This work presents the design, manufacturing and electromagnetic characterization of compact 3-way Wilkinson power divider/combiner prototypes intended to work in the sub-GHz frequency band. The primary objective is to create practical designs in terms of size while achieving a highly symmetric electromagnetic behavior. To accomplish this, a combination of additive manufacturing techniques and copper electroplating processes was employed. Additive manufacturing enables the design of very compact 3D structures, such as helical-microstrip transmission lines, which can reduce the dimensions of the prototypes without compromising wave propagation. Additionally, its 3D nature allows for the design of completely symmetric structures, unattainable with planar technologies. The high quality of electroplated copper ensures low losses. Two prototypes, designed to operate at target center frequencies of 250 MHz and 600 MHz, respectively, were implemented. For comparison purposes a planar 3-way Wilkinson device designed to operate at a target center frequency of 600 MHz was also implemented. S-parameters were simulated and measured around the respective target frequencies to derive port impedance matching, port isolation, and insertion losses. The obtained results confirm the feasibility of very compact Wilkinson devices at the sub-GHz frequency range, with low losses and highly symmetric behavior.
A low-cost colorimetric HKUST-1 sensor for ppm-level humidity detection
(Elsevier B.V., 2025-10-15) González Gómez, María; Martínez Medina, Elizabeth; Kovač, Janez; Casals Guillén, Olga; Martínez López, Mònica; Xuriguera Martín, María Elena; Fàbrega Gallego, Cristian
Accurate detection of trace moisture is critical in various industries, from microelectronics to petrochemicals. While electrical humidity sensors are prevalent, optical methods offer superior sensitivity for low relative humidity (RH) detection, particularly in demanding applications requiring ppb sensitivity in harsh environments. This work explores the potential of HKUST-1, a metal-organic framework (MOF), as a colorimetric humidity sensor for ppm level detection across a broad range (0–80 % RH). By spraying HKUST-1 onto polyester substrates and coupling it with a low-cost, commercially available LED-photodiode module, we developed a simple, portable sensing platform. The observed color transitions, from dark blue to turquoise, correlate with the MOF's moisture adsorption mechanism, achieving a detection limit of 18 ppm H2O (< 0.05 % RH). Comprehensive characterization, including interferent gas studies, revealed significant color changes upon exposure to NH3, CO, and ethanol, while CO2, CH4, and N2O showed minimal interference. One-week stability tests demonstrated consistent sensor performance and full reversibility upon exposure to dry air at room temperature. This low-cost, sensitive, and easily fabricated HKUST-1-based sensor offers a promising alternative for humidity monitoring in diverse industrial applications.
Portable ion mobility spectrometry and partial least squared discriminant analysis for odour source discrimination in wastewater treatment plants
(Elsevier B.V., 2025-11-15) Villa, Veronica; Fernández Romero, Luis; Lotesoriere, Beatrice Julia; Alonso Valdesueiro, Javier; Gutiérrez Gálvez, Agustín; Capelli, Laura; Marco Colás, Santiago
Odour emissions from Wastewater Treatment Plants are a relevant issue concerning environmental and social impact, regulatory compliance, and plant management. Instrumental Odour Monitoring Systems are widely used for real-time odour emissions monitoring, but seasonal and plant variability limit their long-term reliability. Therefore, new sensing technologies and approaches are being studied to improve their reliability and the transferability of predictions between different plants and seasons. In this context, this work investigates the suitability of portable Ion Mobility Spectrometers to discriminate the main odour sources in Wastewater Treatment Plants. Two measurement campaigns were carried out in different seasons, considering different odour sources in two independent plants. Through a proper data analysis approach, based on the importance of ionic information, portable Ion Mobility Spectrometry proved effective in discriminating odour sources from the two main process lines: water and sludge treatment. In the first phase, conducted in the same plant and season, a balanced classification rate of 94 % (95 %CI: 82 %–100 %) was achieved. Subsequently, including seasonal and plant variability, a model trained on one plant was applied to the second. The direct transfer of the calibration achieved a balanced classification accuracy of 96 % (95 %CI: 86 %–100 %), confirming the relevance of the selected ions for odour assessment across different plants. These results suggest that portable Ion Mobility Spectrometry is a technology that deserves further attention for instrumental odour monitoring. The consistent classification rates obtained both within a single plant and when transferring the model demonstrate that Ion Mobility Spectrometry, combined with feature selection, can reliably identify ions specifically relevant for odour emission assessment.
Enhancing the detection of low-energy M dwarf flares: wavelet-based denoising of CHEOPS data
(EDP Sciences, 2024-12-24) Poyatos, Julien; Fors Aldrich, Octavi; Gómez Cama, José María; Ribas Canudas, Ignasi
Stellar flares are powerful bursts of electromagnetic radiation triggered by magnetic reconnection in the chromosphere of stars, occurring frequently and intensely on active M dwarfs. While missions like TESS and Kepler have studied regular and super-flares, their detection of flares with energies below 10^30 erg remains incomplete. Extending flare studies to include these low-energy events could enhance flare formation models and provide insight into their impacts on exoplanetary atmospheres. This study investigates CHEOPS's capacity to detect low-energy flares in M dwarf light curves. Using CHEOPS's high photometric precision and observing cadence, along with a tailored wavelet-based denoising algorithm, we aim to improve detection completeness and refine flare statistics for low-energy events. We conducted a flare injection and recovery process to optimise denoising parameters, applied it to CHEOPS light curves to maximise detection rates, and used a flare breakdown algorithm to analyse complex structures. Our analysis recovered 349 flares with energies ranging from 2.2×10^26 to 8.1×10^30 erg across 63 M dwarfs, with ∼40% exhibiting complex, multi-peaked structures. The denoising algorithm improved flare recovery by ∼34%, though it marginally extended the lower boundary of detectable energies. For the full sample, the power-law index α was 1.92±0.07, but a log-normal distribution fit better, suggesting multiple flare formation scenarios. While CHEOPS's observing mode is not ideal for large-scale surveys, it captures weaker flares than TESS or Kepler, expanding the observed energy range. Wavelet-based denoising enhances low-energy event recovery, enabling exploration of the micro-flaring regime. Expanding low-energy flare observations could refine flare generation models and improve the understanding of their role in star-planet interactions.
CSRR chemical sensing in uncontrolled environments by PLS regression
(Institute of Electrical and Electronics Engineers (IEEE), 2025-09-18) Alonso Valdesueiro, Javier; Fernández Romero, Luis; Gutiérrez Gálvez, Agustín; Marco Colás, Santiago
Complementary Split Ring Resonators (CSRRs) have been widely researched as planar sensors, but their use in routine chemical analysis is limited due to dependence on high-end equipment, controlled conditions, and susceptibility to environmental and handling variations. This work introduces a novel approach combining a CSRR sensor with machine learning (ML) to enable reliable quantification of compounds. A low-cost benchtop CSRR system was tested for ethanol concentration prediction in water (10–96%), using 450 randomized measurements. PCA was applied for data exploration, and a PLS regression model with Leave-One-Group-Out cross-validation achieved a 3.7% RMSEP, six times better than univariate calibration (23.4%). The results show that ML can mitigate measurement uncertainties, making CSRR sensors viable for robust, low-cost concentration analysis under realistic laboratory conditions.
Enhanced photoelectrochemical glycerol oxidation with bismuth gradient BiVO4 photoanodes
(Elsevier Ltd., 2025-10-01) Molera Janer, Martí; Fàbrega Gallego, Cristian; Sarret i Pons, Maria; Andreu Arbella, Teresa
In this work, we propose a novel strategy for synthesizing BiVO4 photoelectrodes for photocatalytic oxidation of glycerol. The two-step electrodeposition process of BiOI, followed by a thermal diffusion of vanadium, results in the formation of a BiVO4 electrode with a bismuth gradient. This gradient leads to excess bismuth clusters at the FTO contact and a stoichiometric proportion at the electrode surface. Structural, optical, and photoelectrochemical characterization revealed that the bismuth gradient acts as an electron transport layer, with superior photoelectrochemical properties in comparison to unmodified BiVO4. This includes lower electron/hole recombination, while maintaining its glycerol oxidation catalytic properties.

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