PT Symmetry Breaking Induced Anomalous Valley Hall Effect in 2D Antiferromagnetic Semiconductor.

Realizing the anomalous valley Hall (AVH) effect in two-dimensional (2D) materials is of crucial importance for information processing and recording technology. While the research in this field mainly focuses on ferromagnetic systems, little is known about antiferromagnetic systems. Here, using k·p model analysis, we report a novel mechanism of realizing the AVH effect in 2D antiferromagnetic materials. This physics is related to the PT symmetry breaking induced by intrinsic staggered sublattice potential, which is introduced by asymmetric magnetic ions located at different sublattices. With reversal of the magnetic orientation on different sublattices, the AVH effect can be reversed. Based on first-principles calculations, we further demonstrate this mechanism in an antiferromagnetic monolayer of NiRuCl6. Intriguingly, due to the d orbital mismatch near the Fermi level, monolayer NiRuCl6 simultaneously owns zero net magnetization and large spin splitting and valley polarizations, which facilitates the observation of the AVH effect. Our findings greatly enrich the research on valley physics in antiferromagnetic systems.

Factors influencing the dissolution rate of radon gas in water.

Measurements of radon (222Rn) in water are widely utilized across various disciplines, including technology, medicine, exploration, and ecological preservation. For accurate radon measurements in water, the availability of a standardized radon solution is essential. Researchers have predominantly concentrated on the radon concentration in water (RCW) once radon distribution equilibrium is achieved, rather than the rate of radon dissolution prior to equilibrium, in the development of standard radon solutions. This makes the preparation speed of the calibration standards radon solution slow, which seriously restricts the research and development of the standard device. The purpose of this paper is to investigate the correlation between the rate of radon dissolution and both the concentration of gaseous radon and the stirring speed. Four conclusions have been derived through univariate analysis. ➀ The radon concentration in water (RCW) increases with the duration of radon dissolution, eventually reaching a state of equilibrium. ➁ The increase in gas radon concentration correlates with a simultaneous rise in the rate of radon dissolution, while the time required for radon distribution equilibrium remains constant. ➂ The augmentation of the stirring speed enhances the rate of radon dissolution, Concurrently reducing the time needed for RCW to reach equilibrium.➃ When the stirring speed is excessively high, it results in substantial fluctuations in both RCW and the rate of radon dissolution. Consequently, when employing this method for the preparation of radon solutions, it is advisable to regulate the duration of radon dissolution to 30 min at a rate of 380 rad/min and 10 min at a rate of 480 rad/min. This regulation ensures the attainment of precise concentrations. Under conditions of environmental stability, manipulation of gas radon concentration alone proves sufficient for adjusting RCW . These empirical findings furnish a robust foundation for the efficient preparation of standardized radon solutions and the requisite apparatus, essential for the calibration and accuracy of radon measurement instruments.

Ferrovalleytricity in a two-dimensional antiferromagnetic lattice.

Control over and manipulation of valley physics via ferrovalleytricity is highly desirable for advancing valleytronics. Current research focuses primarily on two-dimensional ferromagnetic systems, while antiferromagnetic counterparts are seldom explored. Here, we present a general mechanism for extending the ferrovalleytricity paradigm to antiferromagnetic lattices to achieve spin control over valley physics. Our symmetry analysis and k·p model reveal that by introducing a Zeeman field aroused by the proximity effect, spin-switchable non-uniform potential is imposed on the two sublattices of an antiferromagnetic lattice. This enables spin control over the anomalous valley Hall effect, thereby realizing ferrovalleytricity. This mechanism is confirmed in a CrBr3-MnPSe3-CrBr3 heterotrilayer from first principles, where the spin-switchable non-uniform Zeeman effect is exerted on two Mn sublattices when the antiferromagnetic MnPSe3 layer is sandwiched between ferromagnetic CrBr3 layers. Such a non-uniform Zeeman effect combined with valley physics guarantees spin control over the anomalous valley Hall effect, i.e., ferrovalleytricity, in the MnPSe3 layer. Our work will shed light on potential applications of valley physics in antiferromagnetic systems.

Ferroelectrovalley in Two-Dimensional Multiferroic Lattices.

Engineering the valley index is essential and highly sought for valley physics, but currently, it is exclusively based on the paradigm of the challenging ferrovalley with spin-orientation reversal under a magnetic field. Here, an alternative strategy, i.e., the so-called ferroelectrovalley, is proposed to tackle the insurmountable spin-orientation reversal, which reverses the valley index with the feasible ferroelectricity. Using symmetry arguments and the tight-binding model, the C2z rotation is unveiled to be able to take the place of time reversal for operating the valley index in two-dimensional multiferroic kagome lattices, which enables a ferroelectricity-engineered valley index, thereby generating the concept of a ferroelectrovalley. Based on first-principles calculations, this concept is further demonstrated in the breathing kagome lattice of single-layer Ti3Br8, wherein ferroelectricity couples with the breathing process. These findings open a new direction for valleytronics and 2D materials research.

Artesunate attenuates osteoarthritis in mice by promoting MTA1 transcription through a USP7/FoxO1 axis.

Artesunate (ART) is a derivative of artemisinin and has anti-inflammatory, anti-tumor, and anti-angiogenic properties. Although ART has been implicated in osteoarthritis (OA), the mechanism needs to be further dissected. Here, we explored the effects of ART on the development of OA and the underlying mechanism using destabilization of the medial meniscus (DMM) surgical instability model. Mice with OA were developed using DMM and treated with ART. The pathological morphology of knee joint tissues was examined, and the degeneration of joint cartilage was assessed. Mouse knee chondrocytes were isolated and induced with IL-1ß, followed by ART treatment. ART alleviates OA in mice by elevating ubiquitin carboxyl-terminal hydrolase 7 (USP7) expression, and USP7 inhibitor (P22077) treatment mitigated the protective effects of ART on chondrocytes. We also showed that USP7 mediated the deubiquitination of forkhead box protein O1 (FoxO1), while FoxO1 alleviated chondrocyte injury. In addition, FoxO1 promoted metastasis-associated protein MTA1 (MTA1) transcription, and downregulation of MTA1 exacerbated chondrocyte injury. Our study identifies that USP7/FoxO1/MTA1 is a key signaling cascade in the treatment of ART on OA.

Dorsal raphe neurons integrate the values of reward amount, delay, and uncertainty in multi-attribute decision-making.

The dorsal raphe nucleus (DRN) is implicated in psychiatric disorders that feature impaired sensitivity to reward amount, impulsivity when facing reward delays, and risk-seeking when confronting reward uncertainty. However, it has been unclear whether and how DRN neurons signal reward amount, reward delay, and reward uncertainty during multi-attribute value-based decision-making, where subjects consider these attributes to make a choice. We recorded DRN neurons as monkeys chose between offers whose attributes, namely expected reward amount, reward delay, and reward uncertainty, varied independently. Many DRN neurons signaled offer attributes, and this population tended to integrate the attributes in a manner that reflected monkeys' preferences for amount, delay, and uncertainty. After decision-making, in response to post-decision feedback, these same neurons signaled signed reward prediction errors, suggesting a broader role in tracking value across task epochs and behavioral contexts. Our data illustrate how the DRN participates in value computations, guiding theories about the role of the DRN in decision-making and psychiatric disease.

Sliding Ferroelectricity Engineered Coupling between Spin Hall Effect and Layertronics in 2D Lattice.

Coupling the spin Hall effect with novel degrees of freedom of electrons is central to the rich phenomena observed in condensed-matter physics. Here, using symmetry analysis and a low-energy k·p model, we report the sliding ferroelectricity engineered coupling between spin Hall effect and emerging layertronics, thereby generating the layer spin Hall effect (LSHE), in a 2D lattice. The physics is rooted in a pair of T-symmetry connected valleys, which experience spin splitting accompanied by large Berry curvature under spin-orbit coupling. The interaction between the out-of-plane ferroelectricity and electronic properties gives rise to the layer-locked Berry curvature and thus layer-polarized spin Hall effect (LP-SHE) in the bilayers. Such LP-SHE is strongly coupled with sliding ferroelectricity, enabling it to be ferroelectrically reversible. Using first-principles calculations, the mechanism is further demonstrated in a series of real bilayer systems, including MoS2, MoTe2, WSe2, MoSi2P4, and MoSi2As4. These phenomena and insights open a new direction for spin Hall effect.

3D Poly (L-lactic acid) fibrous sponge with interconnected porous structure for bone tissue scaffold.

Large bone defects, often resulting from trauma and disease, present significant clinical challenges. Electrospun fibrous scaffolds closely resembling the morphology and structure of natural ECM are highly interested in bone tissue engineering. However, the traditional electrospun fibrous scaffold has some limitations, including lacking interconnected macropores and behaving as a 2D scaffold. To address these challenges, a sponge-like electrospun poly(L-lactic acid) (PLLA)/polycaprolactone (PCL) fibrous scaffold has been developed by an innovative and convenient method (i.e., electrospinning, homogenization, progen leaching and shaping). The resulting scaffold exhibited a highly porous structure (overall porosity = 85.9 %) with interconnected, regular macropores, mimicking the natural extracellular matrix. Moreover, the incorporation of bioactive glass (BG) particles improved the hydrophilicity (water contact angle = 79.7°) and biocompatibility and promoted osteoblast cell growth. In-vitro 10-day experiment revealed that the scaffolds led to high cell viability. The increment of the proliferation rates was 195.4 % at day 7 and 281.6 % at day 10. More importantly, Saos-2 cells could grow, proliferate, and infiltrate into the scaffold. Therefore, this 3D PLLA/PCL with BG sponge holds great promise for bone defect repair in tissue engineering applications.

Engineering Layertronics in Two-Dimensional Ferromagnetic Multiferroic Lattice.

Layertronics, rooted in the layer Hall effect (LHE), is an emerging fundamental phenomenon in condensed matter physics and spintronics. So far, several theoretical and experimental proposals have been made to realize LHE, but all are based on antiferromagnetic systems. Here, using symmetry and tight-binding model analysis, we propose a general mechanism for engineering layertronics in a two-dimensional ferromagnetic multiferroic lattice. The physics is related to the band geometric properties and multiferroicity, which results in the coupling between Berry curvature and layer degree of freedom, thereby generating the LHE. Using first-principles calculations, we further demonstrate this mechanism in bilayer (BL) TcIrGe2S6. Due to the intrinsic inversion and time-reversal symmetry breakings, BL TcIrGe2S6 exhibits multiferroicity with large Berry curvatures at both the center and corners of the Brillouin zone. These Berry curvatures couple with the layer physics, forming the LHE in BL TcIrGe2S6. Our work opens a new direction for research on layertronics.

Temporally Decoupled Ammonia Splitting by a Zn-NH3 Battery with an Ammonia Oxidation/Hydrogen Evolution Bifunctional Electrocatalyst as a Cathode.

Ammonia splitting to hydrogen is a decisive route for hydrogen economy but is seriously limited by the complex device and low efficiency. Here, we design and propose a new rechargeable Zn-NH3 battery based on temporally decoupled ammonia splitting to achieve efficient NH3-to-H2 conversion. In this system, ammonia is oxidized into nitrogen during cathodic charging (2NH3 + 6OH- → N2 + 6H2O + 6e-) with external electrical energy conversion and storage, while during cathodic discharging, water is reduced to hydrogen (2H2O + 2e- → H2 + 2OH-) with electrical energy generation. In this loop, continuous and efficient H2 production without separation and purification is achieved. With the help of the ammonia oxidation reaction (AOR) and hydrogen evolution reaction (HER) bifunctional catalyst of Mo2C/NiCu@C, a rechargeable Zn-NH3 battery is realized that exhibits a high NH3-to-H2 FE of 91.6% with outstanding durability for 900 cycles (300 h) at 20 mA/cm2, enabling efficient and continuous NH3-to-H2 conversion.