Browse Articles

An electrically driven terahertz metamaterial PIN modulator

A terahertz (THz) amplitude modulator based on a silicon p–i–n structure integrated with a planar metamaterial grating is experimentally demonstrated for free-space operation. Electrical modulation is achieved via bulk injection of nonequilibrium carriers into high-resistivity silicon, resulting in enhanced absorption of terahertz radiation in resonant modes of the structure. Owing to strong electromagnetic field confinement, a modulation depth of up to 26.7 dB is achieved. Time-resolved measurements reveal a switching time of 5.8 μs, governed by carrier recombination dynamics in the silicon bulk. The demonstrated modulator provides an efficient and CMOS-compatible solution for terahertz communication and imaging systems.

Organic Materials of Tomorrow: Horizons of Artificial Intelligence

ABSTRACT Artificial intelligence (AI) is transforming organic materials discovery by enabling the rapid exploration of chemical space. This review examines machine learning techniques being used to accelerate the identification of novel compounds for organic semiconductors through computational approaches linking molecular structure to properties. Key methodologies include graph neural networks, generative approaches, chemical representations, ‐learning frameworks, machine learning force fields, active learning, transfer learning, and generative models. These methods address fundamental challenges in organic materials discovery, from property prediction and inverse design to high‐throughput screening and molecular generation. An example of applications to the topic of organic photovoltaics demonstrates practical impact in predicting energy levels, morphology, charge transport, exciton dynamics, and power conversion efficiency. Rather than replacing human scientists, we envision AI as a tool that amplifies their capacity to explore unconventional regions of chemical space. Advantages, drawbacks and bottlenecks of AI use in chemistry are discussed together with future research directions, such as the adoption of human‐centered AI practices, the construction of materials‐science‐oriented benchmarking databases and protocols, the integration of green chemistry constraints into generative pipelines, and the further exploration of end‐to‐end in‐silico‐to‐technical validation workflows, all tailored to the needs of the materials science community.

Up cycling prickly pear peel waste for sustainable wool dyeing using microwave irradiation

Abstract This study explores the valorization of prickly pear (Opuntia ficus-indica) peel waste as a sustainable natural dye for wool fabrics. Dyeing was conducted using both conventional mordant-assisted (4% tannic acid) and mordant-free microwave-assisted methods. Key parameters including dyeing time and pH were optimized to enhance color strength. Microwave-assisted dyeing substantially reduced processing time and energy consumption compared to the conventional method. The dyed fabrics were evaluated for mechanical properties, color strength, fastness properties, ultraviolet protection factor (UPF), and antibacterial activity. Microwave-dyed samples exhibited higher color strength, improved fastness ratings, higher UPF values, and better antibacterial activity than conventionally dyed samples. In addition, the microwave process produced effluent with lower BOD, COD, and TDS levels. These findings indicate that prickly pear peel extract combined with microwave technology offers a promising eco-friendly approach for producing colored wool fabrics with added functional properties while reducing environmental impact.

Lipid droplet associated protein HILPDA promotes hypoxia-induced ferroptosis by driving LPCAT3-mediated polyunsaturated phospholipids enrichment

Each year, tens of millions of individuals sojourn to high-altitude environments (>2500 m), where they face the significant physiological challenge of hypoxia, a condition that often induces a range of gastrointestinal disorders. While our prior studies linked this damage to ferroptosis, the role of hypoxia-inducible lipid droplet-associated protein (HILPDA), a hypoxia inducible factor-1α/2α (HIF-1α/2α) downstream regulator, in this process remains unclear. This study aimed to explore the role and mechanism of HILPDA in regulating ferroptosis of normal human gastric and small intestinal epithelial cells (NGEC and HIEC) under hypoxic conditions. Our results found that overexpression of HIF-1α, HIF-2α, and HILPDA exacerbated hypoxia-induced cell death, which was reversed by the ferroptosis inhibitor ferrostatin-1. Knockdown of HIF-1α/2α inhibited HILPDA expression. Furthermore, knockdown of HILPDA led to a reduction of the hypoxia-induced lipid peroxidation, and the ferroptotic characteristics of cellular mitochondria observed under transmission electron microscopy. Conversely, HILPDA overexpression reversed the protective effects of HIF-1α/2α knockdown. Lipidomic analysis further revealed that HILPDA knockdown significantly decreased the levels of polyunsaturated fatty acid-phosphatidylcholines (PUFA-PCs) and phosphatidylethanolamines (PEs) under hypoxia. Compared to HIF-1α knockdown, HILPDA knockdown led to a slight difference in PUFA-PEs without significant difference in PCs and phosphatidylinositols (PIs) under hypoxia. Compared to HIF-2α knockdown, HILPDA knockdown resulted in negligible differences in PEs, PCs, and PIs. In addition, HILPDA knockdown downregulated Lysophosphatidylcholine Acyltransferase 3 (LPCAT3), and overexpression of LPCAT3 significantly attenuated the inhibitory effect of HILPDA knockdown on hypoxia-induced ferroptosis. In conclusion, HILPDA enhanced susceptibility to hypoxia-induced ferroptosis in NGEC and HIEC by enriching PUFA-containing phospholipids through LPCAT3. These findings identified the HIF-1α/2α-HILPDA-LPCAT3 axis as a pivotal pathway driving hypoxia-induced ferroptosis, therefore providing potential therapeutic targets for gastric and small intestinal mucosal injury associated with hypoxia.

Correction to “Charge‐Driven Self‐Assembly of Cholesterol Surfactants into Biofunctional Nanodiscs with Antiviral Activity”

Ferroelectric multi-stability and electrically switchable Rashba effect in few-layer M2CO2 (M = Ti, Zr, Hf)

Manipulating the interlayer stacking in van der Waals materials offers a powerful approach for designing emergent quantum devices. Using first-principles calculations, we investigate the layer-dependent ferroelectric and spintronic properties of few-layer M2CO2 (M = Ti, Zr, Hf). In bilayer structures, interlayer sliding breaks the mirror symmetry of the nonpolar parent phase, leading to ferroelectric bistability with a switchable out-of-plane polarization ranging from 1.38 to 4.12 pC/m. In the trilayer configuration, the system exhibits ferroelectric tri-stability, characterized by a stable intermediate nonpolar state flanked by two polar states. This triple-well energy landscape provides a mechanism for ternary data storage. Furthermore, the ferroelectric polarization is coupled to the electronic spin texture, enabling switching between a spin-degenerate state and Rashba-split polar states. These findings establish M2CO2 as a promising candidate material for multi-level memory and nonvolatile spintronic logic devices.

Synthesis of a 3D chitosan/cellulose acetate hydrogel: comparative impact of drying techniques on morphology for sustainable wastewater treatment

Abstract Towards achieving the sustainable development goals, this work contributes to long-term improvements in water and sanitation infrastructure by developing new adsorbents from two naturally based polymers. To address this issue, a novel 3D chitosan/cellulose acetate hydrogel (CCA-HG), crosslinked with minimal glutaraldehyde, was synthesized and dried using two drying techniques: freeze-drying (CCA-HG F ) and air-drying (CCA-HG A ). The impact of the two drying techniques affected the adsorptive efficiency of the two products towards hazardous anionic textile dye. Both hydrogels were comprehensively characterized by FTIR, SEM, XPS, XRD, BET, and swelling capacity, confirming successful crosslinking and distinct morphologies. However, CCA-HG F showed a softer, more porous texture with greater surface area and swelling capacity than CCA-HG A . Applying the batch method indicated that the freeze-drying method produced a better and more efficient adsorbent since CCA-HG F achieved an adsorption capacity of 149.30 mg/g and 99.53% efficiency within 75 min, whereas CCA-HG A demonstrated 20.50 mg/g, 98.44% in 90 min. Adsorption followed a pseudo-second-order model and reached equilibrium within 75–90 min. Isothermal and thermodynamic studies indicated a spontaneous, exothermic, hybrid physical-chemical process. Both hydrogels maintained excellent reusability over five adsorption-desorption cycles. Complementary computational calculations; DFT and molecular dynamics simulations revealed a reduced energy gap (4.055 to 2.476 eV), enhanced charge transfer, and strong non-covalent interactions (–24.544 to − 22.312 Kcal/mol), upon adsorption. To the best of our knowledge, this study establishes freeze-drying as a key strategy for fabricating highly porous, high-capacity biopolymer adsorbents, bridging a crucial gap between sustainable material synthesis and high-performance application.

Electron–electron interaction-driven semiconducting ground state of oxygen-terminated zigzag graphene nanoribbons

Edge engineering of graphene nanoribbons introduces additional correlation effects, and oxygen-terminated edges offer excellent ambient stability. However, oxygen-terminated ribbons are extremely difficult to fabricate within the width of 3 nm, and theoretical predictions for their magnetic and electronic ground states remain conflicting. Here, we report the fabrication of oxygen-terminated zigzag graphene nanoribbons with widths below 3 nm. Using scanning tunneling spectroscopy, we observe an edge state splitting evolving from 0.17 to 0.24 eV as the ribbon width reduced from 3.8 to 2.2 nm. For a 1.8 nm ribbon, we measure a bandgap of 1.04 eV, which opens above the Dirac energy, and an energy shift of phonon modes at K points is also observed in the same region. These measurements experimentally validate hybrid density functional theory predictions for oxygen terminated ribbons and extend the width range for gapped oxygen-terminated ribbons from theoretically 0.8 to 1.8 nm. These findings establish oxygen-terminated nanoribbons as a robust platform for studying correlation and edge physics, and they suggest new opportunities for device applications based on chemically stable, narrow graphene ribbons.

Physalis polysaccharide-sericin nanocarriers for controlled alpha-lipoic acid delivery and improved human sperm cryopreservation

Three-dimensional visualization of lattice defects in <b> <i>β</i> </b> -Ga2O3 via synchrotron-radiation Borrmann-effect X-ray topo-tomography

β-Ga2O3 is a promising material for next-generation power electronics; however, its performance is strongly affected by lattice defects such as dislocations. In this study, we demonstrate three-dimensional (3D) visualization of dislocations in β-Ga2O3 using synchrotron-radiation X-ray topo-tomography under a two-beam Borrmann-effect condition in transmission X-ray topography. By rotating the sample about the diffraction vector and acquiring a series of topo-tomographic images at different rotation angles, the evolution of dislocation contrast is captured, providing intuitive, depth-resolved visualization of dislocations. This method enables clear separation of dislocations in the epilayer and substrate in Schottky barrier diode structures, offering insight into dislocation propagation and their impact on epitaxial growth and device performance. This study represents the first demonstration of 3D dislocation reconstruction in β-Ga2O3.

Altered central vestibular processing in Parkinson’s disease with Pisa syndrome

Abstract In Parkinson’s disease (PD) dizziness, imbalance, postural instability and impaired visuospatial orientation occur, about 10% of PD additionally present with Pisa syndrome (PS). Aim of the current study was (a) to evaluate the perception of verticality by subjective visual vertical (SVV) and visuospatial orientation by the Benton Judgement of Line Test (JLO) in PS, (b) to analyze vestibular reactivity after vestibular stimulation and (c) to compare isolated cervical dystonia (iCD) before and after botulinum neurotoxin (BoNT) treatment. Participants consisted of 20 PD patients (8 with PS), 32 iCD patients and 51 controls. All underwent a clinical examination, evaluation of JLO and SVV. JLO and SVV were tested before and after vestibular activation by galvanic vestibular stimulation (GVS). iCD patients were treated with BoNT and performed a second trial of the study protocol. PS had pathological deviations of SVV (SVV = 2.3 ± 0.7; F = 5.22, p  = 0.002). After GVS this deviation further increased (SVV = 3.1 ± 0.9; F = 7.36, p  &lt; 0.001). The course of the SVV deviation induced by GVS differed significantly (rm-ANOVA: F = 6.09, p  = 0.003), displaying a pathological response to vestibular activation in PS only. For iCD a significant decrease in JLO was detected after GVS (JLO = 11.4 ± 0.5; F = 2.82, p  = 0.043). Finally iCD significantly improved after BoNT treatment, without an effect on SVV. PS patients have pathological perception of verticality. Since SVV deviations further increase in PS after GVS, this points to a pathological central processing of vestibular information. Therefore, PS may be associated with involvement of central vestibular and graviceptive pathways in PD.

Structural characterization of neutron irradiated hexagonal boron-10 nitride-15 single crystals

The negatively charged boron vacancy (VB−) in hexagonal boron nitride (hBN) is a promising quantum defect that can be used to sense pressure, temperature, and magnetic field with high spatial resolution. hBN enriched with the boron-10 and nitrogen-15 isotopes, denoted h10B15N, has good contrast and coherence for quantum sensing because nitrogen-15 has nuclear spin (1/2), reducing hyperfine interactions. Boron vacancies can be generated by neutron irradiation, which causes the transmutation of the boron-10 isotope to lithium-7. In this study, the ancillary structural, compositional, and mechanical properties of h10B15N crystals that have been subjected to neutron irradiation fluences from 1.4 × 1016 to 8.4 × 1017 n/cm2 were thoroughly characterized. Besides creating VB−, the process also induces other defects that generate strain in the crystal lattice. In turn, the mechanical properties of these crystals change drastically. Investigated here are the visual changes, lattice integrity, composition, crystal strain, and elastic constants (C33 and C66) to assess how these characteristics change as a function of neutron fluence.

PoinCLIP-VAD: a hyperbolic cross-modal fusion framework for video anomaly detection

Native oxide-engineered 3D-graphene/silicon photodetectors for imaging sensors and photonic logic applications

Silicon-based optoelectronic devices typically use hydrofluoric etching to remove native silicon oxide (SiO2) from silicon (Si) surfaces, thereby eliminating the interfacial insulating layer and reducing the interface barrier. However, this process increases fabrication complexity and introduces a large density of dangling bonds and interface defects. In this study, the native SiO2 layer is intentionally retained to serve as an additional barrier and tunneling layer. A three-dimensional (3D) graphene/SiO2/Si heterostructure is constructed that alleviates lattice and chemical mismatches between the 3D-graphene and Si. This design minimizes dark current and enhances tunneling transport of photogenerated carriers. The porous 3D-graphene creates nanoscale resonant cavities that improve light absorption through multiple scattering and localized optical field enhancement. The device exhibits long-term stable (4 months) and efficient photoresponse from 380 to 1550 nm, achieving 20 A/W responsivity and 6.9 × 1010 Jones detectivity at 1550 nm, with rapid response times of 180/191 μs. It enables optical signal encryption, photonic logic gate operations (AND/OR), and near-infrared imaging with a pixel array of 200 × 200. This work reveals the role of native oxide layers in Si heterostructure design and offers a strategy for enhancing broadband Si photodetectors.

Hybrid fuzzy AHP–WASPAS optimization of turning parameters for electronic waste-derived aluminum alloys: advancing sustainable machining in line with sustainable development goals and circular manufacturing

Ion magnetization in strong magnetic fields in an electrostatic–magnetic hybrid thruster

An electrostatic–electromagnetic hybrid thruster equipped with a superconducting magnet generating magnetic fields up to 1.13 T was experimentally characterized, focusing on ion magnetization as a novel phenomenon in electric propulsion. Magnetic fields above 0.65 T reduced ion Larmor radii, decreasing wall losses and improving beam utilization. At lower fields (0.44 T or less), multi-ionization also reduced ion Larmor radii. Thrust efficiency reached nearly 25% at two distinct peaks: 1.13 T and 0.44 T. At 1.13 T, high mass flow rates produced a high thrust-to-power ratio due to low discharge current, limited electron cross field transport, and improved beam utilization. At 0.44 T, low mass flow rates resulted in high-specific impulse, enhanced by multiply charged ions. These results demonstrate the potential for dual-mode operation combining high thrust and high-specific impulse.

FFRLS-MPC: An adaptive model predictive control method for robust ship course keeping

Geometric dependence of critical-current variation in Al/AlO <i>x</i> /Al Josephson junctions: A model-based analysis

Achieving uniform critical current across Josephson junctions is essential for the large-scale integration of superconducting quantum circuits. In this work, we statistically analyzed the variation of the critical current of Al/AlOx/Al junctions using room-temperature tunnel resistance statistics and identified the dominant contribution among the modeled sources of the variation based on their dependence on geometry and deposition conditions of junctions. Our model-based analysis reveals that fluctuations in the Al film thickness play the dominant role among the modeled contributing factors. Based on this analysis, we found that, in Dolan-bridge double-angle deposition, adopting a deposition angle of 30° for bilayer junctions significantly improves uniformity, yielding a relative standard deviation of 1.2% (0.5%) across a 9.75 mm (1.5 mm) square region.

Isolation enhancement in a compact 2.4 GHz antenna pair for radar systems

Termination-dependent electronic structure reconstruction in epitaxial EuTe4 thin films

Layered EuTe4 has attracted considerable interest due to its intertwined charge density wave (CDW) phases and unconventional thermal hysteresis. While bulk EuTe4 has been extensively studied, its electronic structure in the thin-film limit remains largely unexplored. Here, we investigate epitaxial EuTe4 thin films and reveal a surface-induced electronic reconstruction absent in bulk crystals. Two distinct surface terminations are identified, and the TeI monolayer termination generates an additional M-shaped valence band derived from Te-pz orbitals. Despite this surface modification, Fermi surface nesting associated with CDW bands is preserved in the thin-film form. Moreover, a pronounced thermal hysteresis of the α band is observed in the temperature range of 9–150 K, in clear contrast to the 100–400 K hysteretic behavior reported in bulk EuTe4. Our results reveal the crucial role of surface termination in reshaping the electronic structure and hysteretic response of EuTe4, establishing thin films as a controllable platform for tuning interacting CDW phases and their hysteretic response.