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Plasmas have been recently studied as topological materials. However, a comprehensive picture of topological phases and topological phase transitions in cold magnetized plasmas is still missing. Here we systematically map out all the topological phases and establish the bulk-edge correspondence in cold magnetized plasmas. We find that for the linear eigenmodes, there are 10 topological phases in the parameter space of density n , magnetic field B , and parallel wavenumber k z , separated by the surfaces of Langmuir wave-L wave resonance, Langmuir wave-cyclotron wave resonance, and zero magnetic field. For fixed B and k z , only the phase transition at the Langmuir wave-cyclotron wave resonance corresponds to edge modes. A sufficient and necessary condition for the existence of this type of edge modes is given and verified by numerical solutions. We demonstrate that edge modes exist not only on a plasma-vacuum interface but also on more general plasma-plasma interfaces. This finding broadens the possible applications of these exotic excitations in space and laboratory plasmas. Magnetized plasma can be regarded as topological matter. Here the authors identify a necessary and sufficient condition for the existence of topological edge mode and find that cold magnetized plasma has ten topological phases in the plasma frequency, cyclotron frequency and wave-vector space.

We show that the dynamical system of an inviscid fluid with velocity shear admits parity-time (PT) symmetry, which provides a physical explanation of the well-known observation that the spectrum of the perturbation eigenmodes of the system is symmetric with respect to the real axis. It is found that the Kelvin-Helmholtz instability is triggered when and only when the PT symmetry is spontaneously broken. The analysis of PT symmetry also reveals that the relative phase between parallel velocity and pressure perturbations needs to be locked at π/2 when the instability is suppressed.

The topological Langmuir-cyclotron wave (TLCW) is a recently identified topological surface excitation in magnetized plasmas. We show that TLCW originates from the topological phase transition at the Langmuir wave-cyclotron wave resonance. By isofrequency surface analysis and two- and three-dimensional time-dependent simulations, we demonstrate that the TLCW can propagate robustly along complex phase transition interfaces in a unidirectional manner and without scattering. Because of these desirable features, the TLCW could be explored as an effective mechanism to drive current and flow in magnetized plasmas. The analysis also establishes a close connection between the newly instituted topological phase classification of plasmas and the classical Clemmow-Mullaly-Allis (CMA) diagram of plasma waves.

Phosphorus (P) and potassium (K) affect seedling growth, root configuration, and nutrient uptake in hydroponic rice, but there are few studies on all growth stages of rice. The purpose of this experiment was to determine the response characteristics of root morphology, plant physiology, and P and K uptake and utilization efficiency to different supplies of P and K. Two local conventional rice varieties (Shennong 265 and Liaojing 294) were used as experimental materials across four treatments, including HPHK (sufficient P and K supply), HPLK (sufficient P supply under low K levels), LPHK (sufficient K supply under low P levels) and LPLK (low P and K levels) in a hydroponic setting. The results showed that HPHK and HPLK significantly decreased the acid phosphatase activity of leaves and roots from full heading to filling stages when compared to LPHK and LPLK. Sufficient supply of P or K significantly increased the accumulation of P and K (aboveground, leaves, stem sheath, and whole plant) and root morphological parameters (root length, root surface area, total root volume, and tips) during major growth stages when compared to LP or LK levels. HPHK was significantly higher than other treatments in terms of dry weight and the root activity at the main growth stage, P and K uptake rates in nutrient solutions at various stages, related P and K efficiency at the maturity stage, yield, effective panicle number, and grain number per panicle. In addition, the effect of HPHK on the above indexes were significantly greater than those of single sufficient supply of P or K. In conclusion, HPHK can improve plant configuration, increase plant P and K absorption and root activity, and increase rice yield and related P and K utilization efficiency.

The type III secretion system (T3SS) is a pivotal virulence mechanism of many Gram-negative bacteria. During infection, the syringe-like T3SS injects cytotoxic proteins directly into the eukaryotic host cell cytoplasm. In Pseudomonas aeruginosa , expression of the T3SS is regulated by a signaling cascade involving the proteins ExsA, ExsC, ExsD, and ExsE. The AraC-type transcription factor ExsA activates transcription of all T3SS-associated genes. Prior to host cell contact, ExsA is inhibited through direct binding of the anti-activator protein ExsD. Host cell contact triggers secretion of ExsE and sequestration of ExsD by ExsC to cause the release of ExsA. ExsA does not bind ExsD through the canonical ligand binding pocket of AraC-type proteins. Using site-directed mutagenesis and a specific in vitro transcription assay, we have now discovered that backbone interactions between the amino terminus of ExsD and the ExsA beta barrel constitute a pivotal part of the ExsD-ExsA interface. Follow-up bacterial two-hybrid experiments suggest additional contacts create an even larger protein–protein interface. The discovered role of the amino terminus of ExsD in ExsA binding explains how ExsC might relieve the ExsD-mediated inhibition of T3SS gene expression, because the same region of ExsD interacts with ExsC following host cell contact.

Remote seawater has been considered a potential refuge for corals in the face of anthropogenic disturbances. However, these remote areas may receive increased atmospheric N deposition, and the ecological consequences remain unclear. This field survey revealed coral-algal phase shifts in the mid-north of the South China Sea. These shifts were observed in 44%, 13.6%, and 26.5% of the sampled reef sites at depths of 1-4 m, 5-8 m, and 10-15 m, respectively. Over 50% of sections in the deeper depths hosted fewer corals compared to shallower areas, coinciding with a higher abundance of macroalgae in the deeper layers. Furthermore, based on long-term observation of atmospheric N flux, laboratory experiments were conducted to explore the cause of coral declines. The results indicate that N supply efficiently promoted macroalgae growth. The saturation of N absorption by macroalgae occurred within 2 weeks, leading to nutrient accumulation in seawater, especially nitrate, which had a direct impact on corals. While moderate N fluxes appeared to mitigate coral bleaching, high N fluxes, even with a balanced P supply or medium level of nutrients with an imbalanced N/P ratio, can both increase the susceptibility of corals to heat bleaching. This study explains the coral-algal phase shift in remote and relatively deep seawater and improves understanding of the cause-and-effect relationship between atmospheric N deposition and coral reef decline.

Background Traditional medical education models emphasizing didactic knowledge transmission inadequately prepare healthcare professionals for complex challenges in modern medicine. Innovation and Entrepreneurship Education (IEE) offers opportunities for fostering innovative thinking, yet limited research systematically examines how medical students experience entrepreneurial learning processes. Accordingly, this study applies Experiential Learning Theory (ELT) to examine how medical students engage with IEE and develop entrepreneurial competencies within healthcare contexts. Methods Semi-structured interviews were conducted with 35 medical students from four Chinese universities who participated in IEE programs (2019–2024). Data were analyzed using thematic analysis, following Kolb’s four-stage experiential learning cycle. Findings Medical students’ participation in IEE maps clearly onto Kolb’s ELT cycle, yet with adaptations shaped by their clinical training. In Concrete Experience phase, students encounter technical, market, and outcome uncertainty (e.g., students described struggling with product design due to limited entrepreneurial knowledge). During Reflective Observation phase, they assess failures as learning opportunities through clinical systems thinking; one team improved innovation by repeatedly re-evaluating unmet clinical needs. Abstract Conceptualization phase involves synthesizing insights into broader models through interdisciplinary dialogue, such as redesigning product materials through interdisciplinary dialogue and expert consultation. In Active Experimentation phase, students apply conceptual models while weighing career implications; for example, some plan to develop medical devices post-graduation, while others reframe their professional identity to include entrepreneurship. Discussion The integration of ELT with IEE addresses unique epistemological challenges medical students face when transitioning between evidence-based clinical reasoning and entrepreneurial thinking. Our adapted framework provides theoretical justification for navigating these contradictions through four interconnected stages connected by transitional processes of reflect, synthesize, apply, and iterate. However, institutional constraints including limited resources, technical capabilities, and regulatory barriers significantly impact learning effectiveness. Conclusion This study makes three theoretical contributions: extending ELT through domain-specific adaptations for medical contexts, establishing a modified framework emphasizing transitional processes, and demonstrating how institutional contexts shape experiential learning outcomes. The integration offers promising pathways for developing innovative capabilities needed in contemporary healthcare by fostering graduates equipped to address complex challenges through entrepreneurial thinking and action.

60NiTi alloys have a tremendous potential to be used in aerospace, marine and automotive industries. There is still a need to further improve the deformability due to the high brittleness of the previously prepared 60NiTi. In this work, 200 °C hot silicone oil was selected as the quenching medium for 60NiTi for the first time to overcome its high brittleness. It is found that the unique microstructure of 60NiTi quenched by hot oil has a lamellar structure composed of a channel-like NiTi matrix and lenticular Ni4Ti3 phase containing a nano-lath NiTi phase. The 60NiTi exhibits a high compression fracture strain of 10% and large reversible strain of 7.5%; which originates from the superelastic behavior of the NiTi SMA constituent. Upon loading, the R phase reorientation releases the stress concentration at the initial stage; while the stress-induced martensitic transformation accommodates the large elastic deformation of the Ni4Ti3 phase at the later stage. This synergistic effect of the two promotes the compressive deformability.

Abstract We show that the dynamical system of an inviscid fluid with velocity shear admits parity-time (PT) symmetry, which provides a physical explanation of the well-known observation that the spectrum of the perturbation eigenmodes of the system is symmetric with respect to the real axis. It is found that the Kelvin–Helmholtz instability is triggered when and only when the PT symmetry is spontaneously broken. The analysis of PT symmetry also reveals that the relative phase between parallel velocity and pressure perturbations needs to be locked at π /2 when the instability is suppressed.

Geometry and topology are two different but closely related concepts in mathematical physics. Geometry is concerned with local differential properties, such as curvatures, while topology is often used to study global properties, such as the number of holes in an object. This thesis demonstrates how geometry and topology manifest themselves in the study of linear waves in plasma. The fundamental objects are the waves’ polarization vector and associated Berry curvatures. The integral of Berry curvatures over a closed parameter space yields a topological index called the Chern number. Topological surface plasma waves can be found when two sides of the surface have different Chern numbers, which can be rigorously proved from an index theorem connecting the Chern numbers and the number of spectral flows. The topological surface waves in cold plasma and Hall magnetohydrodynamics are investigated. As topological waves, they possess the so-called topological robustness, i.e., they are unidirectional and free of scattering and reflection. The dispersion and propagation of the topological surface waves are analyzed and benchmarked numerically.When a quasi-monochromatic electromagnetic wave packet propagates in non-uniform plasmas, the wave’s polarization changes over time and, therefore, picks up a geometric phase. As the gradient of the wave phase, the local wave vector is modified accordingly, and as a result, so is the group velocity. This causes additional bending of the ray trajectory. An electron-cyclotron wave beam in a typical toroidal fusion plasma can deviate by as much as ten wavelengths (∼0.1 m) in the poloidal direction relative to the lowest-order ray trajectory. This is a geometrical effect called the spin Hall effect of waves.