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This study was conducted to understand how applied potential modulates metabolic flux toward succinic acid during xylose electro-fermentation by Actinobacillus succinogenes under varying feed concentrations (15, 20, 25 g/L). Electro-fermentations were conducted with applied potential at −1.5 V and −2.5 V and compared to open circuit control. Product distribution and carbon balance were quantified to assess the effect of potential on pathway routing. Results showed that applied potential consistently reduced formic acid and increased succinic acid selectivity. At 20 g/L xylose, the highest succinic acid yield was 0.80 mol/mol at −2.5 V, a 28.88% increase compared to that of the control (0.62 mol/mol). Formic acid and acetic acid yields were 0.73 and 0.60 mol/mol, representing a 48.83% and 16.09% reduction, respectively. The carbon allocation to succinic acid was 51% with a total carbon recovery of 81%. In addition, the effects of 10 g/L and 15 g/L NaHCO₃, as well as 10 g/L NaHCO₃ supplemented with gaseous CO_2, were evaluated at 15 g/L xylose and −2.5 V. Supplementation with gaseous CO₂ increased succinic acid yield from 0.74 to 0.85 mol/mol and improved total carbon recovery from 75% to 84%. Collectively, these findings show that applied potential, in combination with bicarbonate or CO₂ supply, can be strategically employed to improve succinic acid production. Full article

(This article belongs to the Special Issue Microbial Electrolysis Cells and Microbial Fuel Cells)

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13 pages, 1289 KB

Open AccessArticle

Delta Power in SLC6A1-Related Neurodevelopmental Disorder: Operationalizing Quantitative EEG Metrics for Biomarker Development

by Hamza Dahshi, Marie Varnet, Kimberly Goodspeed, Jacob Tiller, Dallas Armstrong and Deepa Sirsi

Neurol. Int. 2026, 18(3), 58; https://doi.org/10.3390/neurolint18030058 (registering DOI) - 18 Mar 2026

Abstract

Introduction: SLC6A1-related neurodevelopmental disorder (SLC6A1-NDD) is an epileptic encephalopathy linked to mutations in the SLC6A1 gene and is characterized by early-onset seizures and developmental delays. Despite the growing recognition of SLC6A1 as a major cause of early-onset epilepsy, the electrophysiological changes associated with the disorder remain inadequately characterized. This study aims to identify electrophysiological biomarkers of SLC6A1-NDD by characterizing EEG delta power using automated tools, EEGLAB (v2023.1) and Persyst 13, exploring age- and state-related effects. Methods: We analyzed EEG recordings from 20 patients with SLC6A1-NDD and 20 neurotypical age- and sex-matched controls using EEGLAB and Persyst, quantifying delta power and related metrics. The Wilcoxon signed-rank method tested for differences between patients and controls, area under the curve (AUC) values evaluated patient classifier models, and Pearson’s correlation assessed concordance between EEGLAB and Persyst. Results: Patients with SLC6A1-NDD exhibited significantly elevated delta power (19.4 ± 4.1) compared to controls (14.2 ± 3.0; p < 0.001). The mean delta power showed an age-dependent increasing trend in patients (b = 0.5), contrasting with a decline in controls (b = −1.0; p < 0.001). In Persyst, the frequency of delta activity above an optimized threshold best differentiated patients from controls in wake epochs (AUC = 0.93). Concordance between EEGLAB and Persyst was one-to-one but with moderate variability (R² = 0.644; p < 0.001). Conclusions: Elevated delta power is a notable feature of SLC6A1-NDD. Cross-platform comparison demonstrates the feasibility of quantitative EEG analysis, while imperfect concordance highlights the need for pipeline standardization. Future work should validate these findings in larger cohorts and, as suitable reference data emerge, benchmark delta power metrics against age-matched children with other developmental and epileptic encephalopathies. Full article

(This article belongs to the Special Issue The Evolving Role of EEG in Neurological Disorders: Advanced Techniques and Future Directions)

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13 pages, 3081 KB

Open AccessArticle

Impact of Gate Oxide Thickness on the Failure Mechanisms of AC Bias Temperature Instability in SiC MOSFETs

by Guoxing Yin and Guangyin Lei

Electronics 2026, 15(6), 1266; https://doi.org/10.3390/electronics15061266 (registering DOI) - 18 Mar 2026

Abstract

Silicon carbide (SiC) MOSFETs are critical for next-generation power electronics, yet their reliability is challenged by alternating-current Bias Temperature Instability (AC BTI). While charge trapping and Recombination-Enhanced Defect Reaction (REDR) are known degradation pathways, the specific role of gate oxide thickness in determining the dominant mechanism remains unclear. This study investigates the degradation behaviors of SiC MOSFETs with varying oxide thicknesses under 150 kHz Dynamic Gate Stress. By maintaining a constant electric field, we decouple the effects of oxide thickness using high-frequency C-V, quasi-static gate current (I_GS) characteristics, and transconductance analysis. Results reveal that thin-oxide devices exhibit parallel C-V shifts and stable transconductance, indicating degradation driven by deep-level charge trapping. Conversely, thick-oxide devices display significant C-V stretch-out, negligible I_GS peak shifts, and severe transconductance degradation, accompanied by irreversible threshold voltage drift. We conclude that despite identical electric fields, the higher driving voltages in thick-oxide devices trigger severe interface state generation consistent with the REDR model, whereas thin-oxide devices are dominated by bulk oxide trapping. These findings highlight the necessity of thickness-dependent optimization strategies for SiC power devices. Full article

(This article belongs to the Section Power Electronics)

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18 pages, 4293 KB

Open AccessArticle

Controlling Substrate Sulfurization for Reliable Fabrication of Sulfur-Doped Carbon Nitride Photoanodes on FTO

by A. Alfaro-Barajas, D. Monllor-Satoca, Jingshan Luo and T. Lana-Villarreal

Photochem 2026, 6(1), 13; https://doi.org/10.3390/photochem6010013 (registering DOI) - 18 Mar 2026

Abstract

The direct thermal conversion of thiourea on fluorine-doped tin oxide (FTO) substrates is widely used to fabricate sulfur-doped carbon nitride (S-CN) photoelectrodes; however, substrate-induced effects often contribute to photoelectrochemical response. Here, we show that the sulfurization of FTO during thermal treatment leads to the in-situ formation of a tin sulfide underlayer, mainly SnS₂, which significantly contributes to the observed photoresponse. A systematic study as a function of temperature reveals that the formation of sulfur-doped carbon nitride and tin sulfide occurs within a similar temperature window, making temperature control alone insufficient to suppress substrate sulfurization. To overcome this limitation, a thin compact carbon nitride interlayer synthesized from melamine was introduced between the FTO substrate and the S-CN film. This interlayer effectively prevents tin sulfide formation and enables the growth of an adherent S-CN film. The resulting photoanodes exhibit stable photoelectrochemical performance toward water oxidation under alkaline conditions (1M KOH), with an onset potential of ~+0.4 V vs. RHE and stable photocurrents up to 40 μA·cm⁻² under AM 1.5G illumination. Electrochemical impedance spectroscopy confirms that the compact carbon nitride interlayer also acts as an effective charge-blocking barrier. This work provides a reliable strategy to avoid substrate-induced artifacts and establishes clear design guidelines to prepare truly sulfur-doped carbon nitride photoelectrodes. Full article

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20 pages, 1861 KB

Open AccessArticle

Design of a Hardware-Optimized High-Performance CNN Accelerator for Real-Time Object Detection Using YOLOv3 with Darknet-19 Architecture

by Shuo Wu, Manasa Kunapareddy and Nan Wang

Electronics 2026, 15(6), 1264; https://doi.org/10.3390/electronics15061264 (registering DOI) - 18 Mar 2026

Abstract

This research proposes a novel hardware-optimized design to accelerate Convolutional Neural Networks (CNNs) using Verilog HDL. The design is specifically developed for the DARKNET-19 system model, which serves as the backbone of the YOLOv3-tiny algorithm, a widely used framework for real-time object detection in dynamic environments. The CNN architecture was implemented in Verilog HDL and synthesized using Synopsys Design Compiler, with a focus on improving both object detection accuracy and hardware resource efficiency. The proposed design efficiently performs key CNN operations, including convolution, pooling, and activation, enabling faster real-time object detection compared to many existing methods. To improve performance, the hardware design incorporates parallel processing techniques, allowing multiple computations to be executed simultaneously. This significantly reduces the system latency and power consumption. The convolutional layers of the DARKNET-19 architecture are efficiently mapped onto the hardware platform, ensuring optimized data storage and fast memory access, which further enhances processing speed and detection accuracy. An innovative feature of the design is a 2-dimensional image preprocessing module that prepares input images before they are fed into the CNN. This preprocessing stage includes image resizing, brightness normalization, and color adjustment, which helps the CNN process visual data more effectively. After preprocessing, the images pass through several CNN layers. The convolutional layers extract key features from the images, while the pooling and activation layers refine these features to improve detection performance. Finally, the processed data is analyzed by the YOLOv3-tiny algorithm, which identifies and locates objects in the images with high precision. Experimental results demonstrate that the proposed high-speed and resource-efficient hardware architecture is well-suited for real-time object detection applications, particularly in highly dynamic and unpredictable environments. Full article

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12 pages, 710 KB

Open AccessArticle

FTIR-Based Machine Learning Identification of Virgin and Recycled Polyester for Textile Recycling in Industry 4.0

by Maria Inês Barbosa, Ana Margarida Teixeira, Maria Leonor Sousa, Pedro Ribeiro, Clara Sousa and Pedro Miguel Rodrigues

Processes 2026, 14(6), 964; https://doi.org/10.3390/pr14060964 - 18 Mar 2026

Abstract

Advances in Industry 4.0 manufacturing have accelerated the adoption of machine learning (ML) for automated classification. Polyester (PES), a widely used synthetic fiber, competes with natural fibers like cotton and other synthetics, highlighting the need for continuous research and improvement. In the textile sector, distinguishing recycled polyester (rPES) from virgin polyester (vPES) remains challenging due to overlapping chemical signatures and material variability. A combination of Fourier transform infrared (FTIR) spectroscopy and ML has not been explored for this purpose. In this study, we evaluated ML models to discriminate three PES fiber types (45 vPES, 65 rPES, and 55 mixed PES) using 165 FTIR spectra across four spectral regions, R1, R2, R3, and R4, as well as their combined representation. Six ML approaches were tested on data reduced with fast independent component analysis (FastICA) (1–30 components) using an 80/20 train–test dataset split. The Decision Tree classifier achieved the highest Accuracy in four of the five spectral evaluations, with classification accuracies ranging from 66.67% to 77.78% for region R4, which also had a balanced classification profile with an area-under-the-curve (AUC) value of 0.81. Notably, despite the moderate overall Accuracy, the model achieved 100% discrimination of rPES when distinguishing it from both mixed and vPES. Mixed fibers remained the most difficult to classify, highlighting the need for improved feature representation. Full article

(This article belongs to the Special Issue Machine Learning, Control, and Optimization in Manufacturing and Industry 4.0)

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14 pages, 1175 KB

Open AccessArticle

Estimating COVID-19 Epidemiological Dynamics Using Serological Case Data in Maryland

by Eili Y. Klein, Alexander Tulchinsky, Fardad Haghpanah, Gary Lin, Wilbur H. Chen and Jacky M. Jennings

COVID 2026, 6(3), 52; https://doi.org/10.3390/covid6030052 - 18 Mar 2026

Abstract

In the early stages of the COVID-19 pandemic, uncertainty around the extent of SARS-CoV-2 spread hampered policymakers’ understanding of the epidemic’s extent. Mathematical models, which proved vital for aiding decision-making, relied primarily on reported cases that were unreliable due to significant underdetection and underreporting. While serological data was used to improve understanding of the epidemiology, it can be costly and difficult to implement without bias. To counter these issues, we integrated serological data from 7229 remnant serum samples collected in 15 Maryland emergency departments (EDs) in Maryland between August and December 2020 into a Bayesian modeling approach to derive an estimate of the incidence of infection and the case fatality rate during the pandemic’s initial wave. We estimated that 5.2% (95% CI, 3.7–7.2%) of the population of Maryland had been infected by late fall 2020. The inferred reporting rate that was estimated started low (<10% in March 2020) and increased to 32% (95% HDI = 26–41%) by the fall, while the estimated infection fatality rate was likely initially higher but fell to 0.51% (95% HDI = 0.43–0.68%) after 1 September 2020. These results demonstrate how existing ED infrastructure can be leveraged to generate less biased, more accurate estimates of the true prevalence of a disease, improving the ability to make decisions and allocate resources under uncertainty. Full article

(This article belongs to the Special Issue Analysis of Modeling and Statistics for COVID-19, 2nd edition)

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15 pages, 588 KB

Open AccessReview

Genetic Diversity of the Polyomavirus JC and Implications for the Pathogenesis of Progressive Multifocal Leukoencephalopathy

by Michael P. Wilczek and Sebastien Lhomme

Viruses 2026, 18(3), 378; https://doi.org/10.3390/v18030378 (registering DOI) - 18 Mar 2026

Abstract

JC Polyomavirus (JCPyV) is a non-enveloped virus with circular double stranded DNA responsible for the rare but fatal demyelinating disease known as progressive multifocal leukoencephalopathy (PML). In its host, this virus exists in two different forms: one found in the periphery, named archetype, and another found in the central nervous system, named prototype. This form usually harbors recombinations in the non-coding control region (NCCR), a key region that contains sequences regulating viral replication and containing binding sites for cellular transcription factors. This form also contains mutations in the capsid protein, especially VP1. Due to the diversity of the JCPyV, a natural polymorphism also exists between the different genotypes. In this review, we aimed to summarize the main features of the archetype and prototype strains in order to facilitate the interpretation of sequence data that are increasingly generated by new sequencing technologies. This will also help to distinguish mutations associated with the natural polymorphism from those specific to the prototype form. Full article

(This article belongs to the Special Issue JC Polyomavirus)

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18 pages, 2867 KB

Open AccessArticle

Evaluation of a Commercial Ozonated Olive Oil Product (800 mEq O₂/Kg) Against Methicillin-Resistant Staphylococcus pseudintermedius (MRSP) Using an Ex Vivo Canine Skin Model

by Hilke Oltmanns, Aimara Bello Suarez-Kupka, Christina Puff, Jessica Meißner and Andrea Vanessa Volk

Pathogens 2026, 15(3), 323; https://doi.org/10.3390/pathogens15030323 - 18 Mar 2026

Abstract

Background: Methicillin-resistant Staphylococcus pseudintermedius (MRSP) represents an emerging challenge in veterinary dermatology. Commercially available ozonated oils promise antibacterial activity, but their efficacy under physiologically relevant conditions remains unexplored. Objective: We aimed to evaluate the efficacy of commercial ozonated olive oil product (800 mEq O₂/kg) against MRSP using an established in vitro model and a newly presented ex vivo canine skin model. Materials and Methods: In vitro susceptibility testing determined minimum inhibitory concentrations (MIC) and time–kill kinetics. Subsequently, canine skin samples were mounted in Franz diffusion cells, inoculated with MRSP (~10⁶ colony-forming units [CFU]), and treated for 8 h with ozonated or placebo olive oil. Bacterial viability was assessed by quantitative culture and histopathology. Results: In vitro testing demonstrated antibacterial activity for ozonated oil (MIC < 20% v/v) compared to placebo oil (90% v/v), with ozonation-specific bactericidal effects. However, ex vivo testing showed no MRSP reduction for either oil versus untreated controls, with bacterial localization in superficial dermis unchanged. Conclusions: Despite in vitro activity, this ozonated olive oil failed to reduce MRSP in ex vivo skin, revealing that tissue barriers prevent antibacterial delivery. These findings demonstrate that in vitro screening cannot predict topical efficacy and emphasize the necessity of tissue-based validation before clinical use. Full article

(This article belongs to the Section Bacterial Pathogens)

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20 pages, 4299 KB

Open AccessArticle

Establishment Mechanism of Power-Frequency Follow-Current Arc on Medium-Voltage Insulated Conductors Under Lightning Overvoltage

by Xin Ning, Rui Yu, Longchen Liu, Jiayi Wang, Jingxin Zou, Hao Wang, Tian Tan, Huajian Peng and Xin Yang

Inventions 2026, 11(2), 28; https://doi.org/10.3390/inventions11020028 - 18 Mar 2026

Abstract

Lightning-induced breaking accidents of medium-voltage insulated conductors pose a serious threat to the safety of distribution networks, and the key cause lies in the establishment and sustained combustion of the power-frequency follow-current arc after lightning overvoltage breakdown. This paper systematically investigates the formation mechanism and critical conditions of power-frequency follow-current arcs using combined simulation and experimental approaches. Based on the streamer discharge theory, a lightning breakdown model was established and combined with the arc energy balance equation, revealing that the establishment of power-frequency follow-current arcs is essentially determined by the post-breakdown energy competition process. The simulation results show that the required anode electric field strength for lightning breakdown is not less than 3 kV/mm. When the power-frequency voltage reaches 10 kV, Joule heating of the arc continuously exceeds heat dissipation loss, enabling restrike after zero-crossing and sustaining stable burning. Experiments verified this voltage threshold and further revealed that the arc establishment rate exhibits nonlinear growth with increasing power-frequency voltage, exceeding 90% at power-frequency voltages ≥ 10 kV. The study also reveals that increased gap distance reduces the arc establishment rate, while the introduction of insulators can enhance it by approximately 20%. This study clarifies the energy criterion for power-frequency follow-current arc establishment and the influence patterns of key parameters, providing theoretical basis and engineering reference for lightning protection design and arc suppression in medium-voltage insulated lines. Full article

(This article belongs to the Section Inventions and Innovation in Design, Modeling and Computing Methods)

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24 pages, 6872 KB

Open AccessArticle

Characterisation of Naturally Occurring MERS-CoV Spike Mutations and Their Impact on Fusion and Neutralisation

by Rachael Dempsey, Hannah Goldswain, Joseph Newman, Nazia Thakur, Tracy MacGill, Todd Myers, Robert Orr, Dalan Bailey, James P. Stewart, Waleed Aljabr and Julian A. Hiscox

Viruses 2026, 18(3), 377; https://doi.org/10.3390/v18030377 - 18 Mar 2026

Abstract

In this study, the phenotypic consequences of naturally occurring single nucleotide polymorphisms (SNPs) in the Middle East respiratory syndrome coronavirus (MERS-CoV) Spike protein were investigated. The impact of Spike mutations on the syncytia formation and neutralisation of contemporary MERS-CoV strains is not currently well understood. Mutations were identified by aligning 584 MERS-CoV Spike sequences from either human clinical isolates collected between 2012 and 2024 or from a clinical isolate that had been passaged in human cells. Fifteen SNPs of interest occurring in the N-terminal domain (NTD), receptor binding domain (RBD) and adjacent to the S1/S2 cleavage site were selected for further characterisation based on their location in the Spike protein, frequency and identification in previous studies. A contemporary clade B, lineage 5 wildtype Spike sequence, obtained from a human MERS-CoV clinical isolate, was used as the backbone in this study. The mutations of interest were introduced to the wildtype backbone to generate Spike variants. Spike variants were characterised via cell–cell fusion assays, and a lentiviral pseudotyping system was used to investigate the impact of these Spike mutations on neutralisation. The I529T, E536K and L745F mutations were shown to increase fusion and syncytia formation. The L411F, T424I, L506F, L745F and T746K mutations were found to increase resistance to neutralisation by pooled patient sera. This study has identified novel naturally occurring Spike mutations that resulted in phenotypic differences in the syncytia formation and neutralisation of contemporary MERS-CoV strains. Continued investigation of the phenotypic consequences of MERS-CoV Spike mutations is essential for assessing the risk to public health, especially given the pandemic potential of this virus. Full article

(This article belongs to the Section Coronaviruses)

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10 pages, 2122 KB

Open AccessArticle

Elastic Properties and Piezoelectric Energy Harvesting of a Lead-Free Hybrid Perovskite, (DABCO)RbBr₃

by Yiming Liu, Guangyue Shi, Changliang Li and Feng Luo

Molecules 2026, 31(6), 1013; https://doi.org/10.3390/molecules31061013 - 18 Mar 2026

Abstract

Mechanical properties of lead-free hybrid perovskites have attracted growing interest because of their significance in future eco-friendly optoelectronic applications. However, there are very limited studies about the intrinsic elastic properties and high-pressure structural evolution of hybrid perovskites, and the fundamental structure–mechanical property relationships are insufficiently understood. Here, we report the elastic behavior of a three-dimensional (3D) hybrid organic–inorganic perovskite, (DABCO)RbBr₃ (DABCO = triethylenediammonium), and confirm the processability through processing with chiral metasurfaces and the generation of circular dichroism. Our in situ high-pressure synchrotron X-ray diffraction experiments demonstrate that this crystal does not start to amorphize until 2.3 GPa. Density functional theory calculations reveal that its E, G and v range between 20.73 and 27.93 GPa, 8.21 and 11.62 GPa and 0.18–0.39, respectively. Additionally, due to the low elastic moduli and polar crystal structure, we fabricate a device of (DABCO)RbBr₃ composite film, which shows favorable performance for piezoelectric energy harvesting. This work utilizes (DABCO)RbBr₃ to open up new avenues for applications in manufacturing and energy harvesting. Full article

(This article belongs to the Special Issue 30th Anniversary of Molecules: Recent Advances in Organometallic Chemistry)

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14 pages, 2310 KB

Open AccessArticle

Photo-Triggered Charge Control Induces Dissociation of Complex Coacervates

by Rei Kakitani, Tomoya Nishimura, Thi Ngan Vu, Chisato Kizaki and Shin-ichi Yusa

Polymers 2026, 18(6), 739; https://doi.org/10.3390/polym18060739 - 18 Mar 2026

Abstract

In this study, we designed a statistical polyampholyte bearing cationic quaternary ammonium salts and anionic phosphate groups as pendant functionalities. In addition, small amounts of o-nitrobenzyl groups, which generate anionic species upon photoirradiation, were introduced into the pendant chains to prepare a photo-responsive polyampholyte via reversible addition-fragmentation chain transfer radical polymerization. By increasing the feed ratio of the cationic monomer during copolymerization, a polyampholyte with a net positive charge was obtained. Upon photoirradiation of the aqueous solution of this cationic polyampholyte, the fraction of negatively charged groups in the polymer increased, resulting in a decrease in the zeta potential from positive values to around 0 mV. When the photo-responsive cationic polyampholyte was mixed with an anionic polyelectrolyte, poly(2-acrylamido-2-methylpropanesulfonate) (PAMPS), in water, micrometer-sized coacervate droplets were formed via electrostatic interactions. Photoirradiation of the aqueous coacervate system increased the fraction of negative charges in the polyampholyte, thereby weakening the electrostatic interactions with anionic PAMPS and resulting in the dissociation of the coacervates. Overall, this study presents a design guideline for polymeric materials in which interpolymer electrostatic interactions can be controlled by light to induce the disappearance of coacervates. Full article

(This article belongs to the Special Issue Stimuli-Responsive Polymers: Advances and Prospects)

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20 pages, 12597 KB

Open AccessArticle

Performance Evaluation of Biped Unit in LARMbot HumanoidV.3

by Alexandra Leonova, Matteo Russo, Cuauhtemoc Morales-Cruz and Marco Ceccarelli

Designs 2026, 10(2), 35; https://doi.org/10.3390/designs10020035 - 18 Mar 2026

Abstract

This paper presents the mechanical design and experimental evaluation of the biped unit of LARMbot V.3—a compact low-cost humanoid robot for educational and research purposes. The biped unit features a modular architecture with a parallel leg mechanism for bipedal locomotion. The mechanical configuration of the unit is introduced, highlighting improvements on previous versions in terms of compactness and operating efficiency. A functional prototype is developed and described with detailed specifications of its actuation and transmission systems. To evaluate the performance of the proposed design, experimental tests were conducted both in-air and on-ground, demonstrating the robot’s ability to perform repeatable walking cycles. The results confirm the feasibility of the design and its potential as a platform for further developments in humanoid locomotion. Full article

(This article belongs to the Special Issue Advancements in Robotic Design, Manufacturing, and the Action-Perception Loop)

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18 pages, 3555 KB

Open AccessReview

The Potential for Hadronic Particle Acceleration in Galactic Pulsar Wind Nebulae

by Alison M. W. Mitchell and Samuel T. Spencer

Universe 2026, 12(3), 85; https://doi.org/10.3390/universe12030085 - 18 Mar 2026

Abstract

Pulsar wind nebulae (PWNe), formed when the wind originating from a rapidly rotating neutron star flows out into its surroundings, have now been observed across the electromagnetic spectrum from the radio to the PeV gamma-ray regime. For most of these sources, leptonic processes, where electrons interacting with background photon fields produce high-energy photons through inverse Compton scattering, are believed to be the origin of associated very-high-energy gamma-ray emission. As such, these objects cannot contribute significantly to the galactic hadronic cosmic ray flux at ∼TeV-PeV energies. However, in a handful of cases, the possibility for an energetically sub-dominant hadron population being accelerated and producing very to ultra-high energy gamma-rays through pion decay has not yet been comprehensively excluded. Such scenarios have received renewed attention in the light of recent results from the Large High Altitude Air Shower Observatory (LHAASO). In this review, we explore the theoretical background positing hadronic acceleration in galactic PWNe, considering cases where the hadrons escape from the pulsar surface and/or are accelerated in the wind, as well as potential ‘shock mixing’ scenarios. We also explore current and future possible constraints on a hadronic component to PWNe from observations. Full article

(This article belongs to the Special Issue Studying Astrophysics with High-Energy Cosmic Particles)

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