Browse Articles

Ultra-broadband ventilation sound insulation by honeycomb hollow-out acoustic metasurface

Conventional ventilation sound insulation requires closed cavities to sustain strong acoustic resonance for reflecting incident waves. In this Letter, we propose a different meta-structure design that uses honeycomb hollow-out acoustic metasurface (HHAM) to realize ventilation sound insulation. The HHAM unit exhibits dual capabilities of very high ventilation sound insulation at resonance and also effective broadband sound attenuation. The well-designed multi-unit HHAM design achieves fine performance with an ultra-thin profile of only 53 mm (0.17λ) and 30% open area with average sound transmission loss exceeding 15 dB from 1100 to 2500 Hz. The proposed design offers a compelling combination of ultra-broadband, effective ventilation, structural simplicity, and fabrication feasibility. Experimental results agree well with numerical simulations and theoretical predictions. Our findings offer a promising pathway for the design of ventilated acoustic metasurfaces and may facilitate practical applications in noise control and architectural acoustics.

Performance enhancement and microstructural characterization of pine fiber-reinforced rammed earth stabilized with limestone powder and LC3

Mechanism of point-defect-driven evolution in ferroelectricity of AlScN films

The performance and reliability of wurtzite-type ferroelectric AlScN films are critically influenced by point defects, particularly nitrogen vacancies (VN·,(··),(···)), although a systematic understanding of their impact remains limited. This study demonstrates the effective modulation of point defects in AlScN films by controlling the Ar/N2 ratio during sputtering and employing successive depositions under a pure N2 atmosphere. We reveal that a high density of point defects induces domain pinning and leads to the split switching current peak. Furthermore, the reduction of point defects facilitates a transition in the switching kinetics from the nucleation-limited switching model to the Kolmogorov–Avrami–Ishibashi model, indicating a defect-mediated evolution from a multi-domain to a more uniform domain structure. Ultimately, this defect-engineering strategy enables an endurance of over 107 cycles in AlScN-based capacitors. These findings establish defect engineering as a viable pathway to optimize performance and endurance in AlScN-based memory devices.

Conceptual modeling of child temperament, emotional and behavioral problems, and parenting style in relation to children’s oral health and dental visit behavior

Enabling high giant magnetoresistance in simple spin valves with ultrathin seed and free layers

Emerging spin–orbit torque devices based on spin valves require a thin magnetic free layer to maximize the torque per moment. However, reducing the free-layer thickness to ≲2 nm deteriorates the giant magnetoresistance (GMR) signal for electrical readout. Here, we demonstrate that the addition of a 1 nm Cu seed layer promotes sharp interfaces in simple polycrystalline Co-based spin valves, enabling high GMR ratios of 5%–7% at sub-2 nm free-layer thicknesses. Our work offers a pathway for engineering high-signal GMR readout in spin–orbit torque digital memories and neuromorphic computers.

Correction: WF-PINNs: solving forward and inverse problems of burgers equation with steep gradients using weak-form physics-informed neural networks

High-performance piezotronic quantum wells by tuning the quantum-confined Stark effect

Recent advances in quantum piezotronics have highlighted the potential of strain-induced polarization fields to modulate quantum transport properties and manipulate quantum states in nanodevices. In this work, we theoretically investigate the effect of strain-induced polarization field on the quantum-confined Stark effect (QCSE) in a piezotronic device based on AlGaN/GaN quantum wells. By applying strain, we investigate fundamental properties such as interband transition energy, electron–hole wavefunction overlap, and aluminum composition dependence. The results demonstrate that the piezotronic effect enables effective modulation of carrier recombination. By enhancing the QCSE, the photodetector can achieve an ultrahigh responsivity of 1.8 × 106 A/W, representing a 170% improvement under a stress of −20 GPa. This work provides guidance for the design of high-efficiency optoelectronic devices and enriches the theoretical foundation of quantum piezotronics and piezo-phototronics.

Daily briefing: Women’s academic careers are knocked by parenthood much more than men’s

Synthesis, antimicrobial evaluation, molecular docking, and drug-likeness assessment of novel phenothiazine chromene hybrid compounds

Abstract By carefully hybridizing with scaffolds generated from chromene, pyranochromene, and cyanoacetamide, a novel class of phenothiazine-based heterocycles was created. IR, NMR, and MS investigations were used to establish the structural integrity of each molecule. Several derivatives showed considerable inhibitory activity, especially compounds 4 , 7 , and 10 , which had MIC values ranging from 3.9 to 15.6 µg/mL against both Gram-positive and Gram-negative bacteria, according to the antimicrobial assessment. The majority of compounds met Lipinski’s criteria, indicating favorable oral bioavailability, according to the drug-likeness assessment. Significant binding affinity was shown by molecular docking against Staphylococcus aureus β-lactamase (PDB: 3G7B). Compound 7 had the best docking score (–5.99 kcal/mol), followed by compound 4 (–5.86 kcal/mol), which was supported by important hydrophobic and hydrogen-bonding interactions with Asp73, Arg76, and Lys103. These findings demonstrate the possibility of phenothiazine–chromene hybrids as viable options for creating novel antimicrobial medicines that effectively combat infections that are resistant to multiple drugs.

Inverse design epsilon-near-zero-based broadband nonreciprocal thermal emitter using hybrid deep learning framework

Nonreciprocal thermal radiation, which breaks Kirchhoff's law by decoupling absorptivity and emissivity, is essential for advanced radiative heat transfer control. However, achieving broadband and tunable nonreciprocal thermal radiation with high design efficiency remains a challenge. This study proposes a novel hybrid deep learning framework, integrating the Artificial Rabbit Optimization and tandem neural network, to inversely design multilayer films (MLFs) based on magnetized gradient epsilon-near-zero (ENZ) InAs layers. By using the Artificial Rabbit Optimization algorithm, we collect a high-quality dataset with a noise ratio of only 3.2%, significantly reducing computational overhead compared to random sampling. The multitasking tandem neural network converges to a low cost function of 0.086, improving the accuracy and avoiding the scattering problem faced by traditional neural networks. Results show that significant nonreciprocal thermal radiation (nonreciprocity > 0.637 and peak 0.723) is achieved in the 14–19 μm range by exploiting the magneto-optical effects of InAs and ENZ-induced Brewster modes. Furthermore, the MLFs exhibit reversed absorptivity and emissivity spectra under reversed magnetic fields. These findings provide a data-efficient and scalable solution for dynamic thermal management and infrared camouflage, demonstrating the powerful synergy between deep learning and nonreciprocal photonics.

Static electricity is a mystery but invisible carbon may be key

MiR-362-3p inhibits the proliferation, migration and EMT of gastric cancer cells by regulating the DEP-1/ERK signaling pathway

Excitation-dependent multi-color emission in lead-free double perovskites with Er3+–Yb3+ cross relaxation for information encryption

Lead-free halide double perovskites have emerged as ideal host materials for ion doping due to their inherent structural stability, low toxicity, and unique ability to accommodate multiple luminescent centers. These characteristics render them highly promising candidates for advanced applications such as intelligent optical anti-counterfeiting and information encryption. In this work, we present a multimodal excitation luminescence design of co-doped Cs2NaScCl6:Er3+, Yb3+, and Sb3+ phosphors. The incorporation of Er3+ and Yb3+ ions not only enables both downconversion and upconversion luminescence with different excitations but also endows multi-color emissions from green to red light through the unique cross-relaxation effect. Furthermore, the introduction of Sb3+ ions creates an efficient energy transfer pathway from self-trapped excitons to Er3+ ions and also achieves a synergistic enhancement of the photoluminescence quantum yield, reaching an outstanding value of 71.24%. Leveraging these excitation-dependent multi-color luminescent properties, we implement multilevel anti-counterfeiting and information encryption applications. This work highlights the significant advantages of ion-doped rare-earth-based double perovskites in advanced optical security technologies.

Now is the time for scientific societies to guide global research

Surface water quality and heavy metal assessment in a tropical coastal zone for identifying favorable crop production seasons

Frequency-modulated enhancement of microwave resonator sensing

We use the Pound–Drever–Hall (PDH) technique to characterize the frequency stability of a microwave-frequency surface acoustic wave resonator-based sensor. The multi-mode acoustic resonator is integrated in a notch geometry with a transmission line, all fabricated on Y-cut lithium niobate. We measure the amplitude and phase of the resonator's transfer function and the PDH signal across the resonator's full spectral range. We use these measurements to emphasize the differences between the PDH measurement and a standard Phase-Locked Loop (PLL) technique. As compared to a PLL, we demonstrate that PDH is insensitive to phase error and exhibits a reduced Allan deviation of the center frequency measurement, in each case by up to an order of magnitude. The method rejects spurious effects and background frequency drift, demonstrating the enhancements possible with PDH-based measurements, which can be realized in a wide range of microwave-frequency resonator-based sensors and devices.

The role of comorbidity and frailty in shaping the burden of atrial fibrillation: a multinational cross-sectional survey

Abstract Atrial fibrillation (AF) is the most common arrhythmia in older adults and often coexists with other chronic conditions, exacerbating physical and cognitive decline and contributing to frailty. The interplay between frailty and comorbidity in AF remains underexplored, particularly regarding quality of life (QoL), health management, and outcome prioritization. Within the AFFIRMO project, this study investigated the experiences of older adults with AF and at least one chronic condition via an online survey. Frailty was assessed using the FRAIL questionnaire, and participants were grouped by frailty status and number of comorbidities. Health-related quality of life (HRQoL) was measured using the EQ-5D-3L and Visual Analogue Scale (VAS). Challenges in health management and prioritized outcomes were also explored. We included 659 participants (median age 72 years, 52.8% female). Those with pre-frailty or frailty and ≥ 3 comorbidities reported the poorest HRQoL. Comorbidity, particularly combined with frailty, was associated with health management difficulties, including healthcare visits, polypharmacy, and mobility limitations. Across all groups, maintaining independence and improving QoL were prioritized outcomes. Pain relief was especially important for those with higher comorbidities. In older adults with AF, comorbidity and frailty significantly affect QoL and health burden. Tailored, patient-centred care strategies and routine assessment of frailty and comorbidity are essential to improve care coordination and outcomes.

Mechanism for enhancing the power conversion efficiency of Cu2ZnSn(S,Se)4 solar cells via MgF2 anti-reflection coating deposition

In this study, MgF2 anti-reflection coatings (ARCs) with different thicknesses were deposited on the surface of Indium Tin Oxide (ITO) located between Ag electrodes of a CZTSSe solar cell by vacuum evaporation deposition. The thickness of the MgF2 ARC was controlled by varying its weight in the range of 0.01–0.04 g of MgF2. By optimizing the weight, the power conversion efficiency (PCE) of the CZTSSe solar cell increased from 10.40% without MgF2 ARC to 12.21% with MgF2 ARC produced with 0.02 g of MgF2. It was found that the increased PCE stems not only from an increase in short-circuit current density (JSC) but also from fill factor (FF). This is different from the previously reported literature results, where the increased PCE was usually attributed to an enhancement in JSC. By calculating the percentage contribution of photogenerated current density (JL) and electrical parameters to JSC and FF, it was demonstrated that the increased JSC is mainly attributed to an increase in JL, and the increased FF is attributed to a decrease in series resistance (Rs), reverse saturation current density (J0), and ideality factor of diode (A). The increase in JL results from the reduction of incident light loss by the anti-reflection effect of MgF2, the decrease in Rs from a decrease in resistivity of ITO caused by diffusion of F from MgF2 into ITO, and the decrease in A and J0 from a slight increase in carrier recombination due to Mg diffusion into ITO and a significant reduction in interfacial recombination because the device was annealed during thermal evaporation of MgF2.

Integrated reservoir quality index (IRQI): a novel approach for reservoir quality assessment

Controlled p-type doping in (111)NiO epitaxial films through ions irradiation

The effect of irradiation by Ar ions with energy of 300 keV and different fluences (F) on the structural and transport properties of (111)  nickel oxide (NiO) epitaxial films is investigated. It has been found that the crystallinity and surface morphology of the films remain mostly unaffected upon irradiation even at the highest fluence of 1×1016 ions/cm2. The study further shows the development of a compressive strain in the irradiated films, which has been attributed to the formation of vacancy type defects in the lattice. Transport studies on the field effect transistors fabricated on both the irradiated and unirradiated samples reveal the enhancement of both mobility and concentration of the holes upon irradiation. While the concentration enhancement can be attributed to the Ni-vacancy type defects, which are predicted to act as shallow acceptors in NiO, the increase in mobility can be explained in terms of the improvement of crystallinity of the film upon irradiation. Our study thus offers a viable pathway for area-selective p-type doping via controlled Ni-vacancy formation.