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The first known magnetic mineral, magnetite, has unusual properties, which have fascinated mankind for centuries; it undergoes the Verwey transition around 120 K with an abrupt change in structure and electrical conductivity. The mechanism of the Verwey transition, however, remains contentious. Here we use resonant inelastic X-ray scattering over a wide temperature range across the Verwey transition to identify and separate out the magnetic excitations derived from nominal Fe 2+ and Fe 3+ states. Comparison of the experimental results with crystal-field multiplet calculations shows that the spin–orbital dd excitons of the Fe 2+ sites arise from a tetragonal Jahn-Teller active polaronic distortion of the Fe 2+ O 6 octahedra. These low-energy excitations, which get weakened for temperatures above 350 K but persist at least up to 550 K, are distinct from optical excitations and are best explained as magnetic polarons. The Verwey transition of magnetite is complex due to the coexistence of strong correlations and electron-phonon coupling. Here, the authors use resonant inelastic X-ray scattering to show evidence for magnetic polarons in magnetite and provide insight into the nature of the transition.

Magnetic fields have an important role in the evolution of interstellar medium and star formation 1 , 2 . As the only direct probe of interstellar field strength, credible Zeeman measurements remain sparse owing to the lack of suitable Zeeman probes, particularly for cold, molecular gas 3 . Here we report the detection of a magnetic field of +3.8 ± 0.3 microgauss through the H  I narrow self-absorption (HINSA) 4 , 5 towards L1544 6 , 7 —a well-studied prototypical prestellar core in an early transition between starless and protostellar phases 8 – 10 characterized by a high central number density 11 and a low central temperature 12 . A combined analysis of the Zeeman measurements of quasar H  I absorption, H  I emission, OH emission and HINSA reveals a coherent magnetic field from the atomic cold neutral medium (CNM) to the molecular envelope. The molecular envelope traced by the HINSA is found to be magnetically supercritical, with a field strength comparable to that of the surrounding diffuse, magnetically subcritical CNM despite a large increase in density. The reduction of the magnetic flux relative to the mass, which is necessary for star formation, thus seems to have already happened during the transition from the diffuse CNM to the molecular gas traced by the HINSA. This is earlier than envisioned in the classical picture where magnetically supercritical cores capable of collapsing into stars form out of magnetically subcritical envelopes 13 , 14 . An analysis of Zeeman measurements reveals that the reduction of magnetic flux relative to mass, which is necessary for star formation, seems to have occurred earlier than previously thought.

Postoperative recurrence and metastasis have crucial roles in the poor prognosis of gastric cancer patients. Previous studies have indicated that gastric cancer originates from cancer stem cells (CSCs), and some investigators have found that a particular subset of CSCs possesses higher metastatic capacity. However, the specific mechanism remains uncertain. In the present study, we aimed to explore the biological functions of the inflammatory cytokine interleukin-17 (IL-17) in gastric cancer metastasis and the distinct IL-17-induced transformation of quiescent gastric CSCs. Our results showed that invasive gastric CSCs were CD26+ and CXCR4+ and were closely associated with increased metastatic ability. The quiescent gastric CSCs, which were CD26− and CXCR4−, were exposed to appropriate concentrations of IL-17; this resulted in the decreased expression of E-cadherin and the increased expression of vimentin and N-cadherin. In addition, the upregulation of IL-17 both in vitro and in vivo resulted in a significant induction of invasion, migration and tumor formation ability in gastric CSCs compared with the control group, which was not treated with IL-17. Further experiments indicated that the activation of the downstream phosphorylated signal transducer and activator of transcription 3 (STAT3) transcription factor pathway was facilitated by IL-17. On the contrary, the downregulation of STAT3 by the specific inhibitor Stattic significantly reversed the IL-17-induced epithelial–mesenchymal transition (EMT)-associated properties of quiescent gastric CSCs. Moreover, tumorigenesis and metastasis were suppressed. Taken together, we suggest that IL-17 is positively correlated with the transformation of quiescent gastric CSCs into invasive gastric CSCs and that targeting IL-17 may emerge as a possible novel therapeutic strategy for gastric cancer.

Background Stroke is one of the primary causes of disability in China and around the world, having an impact on the health and well-being of stroke patients. The importance of spiritual needs for stroke patients has always been a controversial topic internationally, partly because related research was mostly qualitative and may not directly reflect the degree of spiritual needs. In addition, most studies focus on the same cultural background, there is a lack of research that delves into the nuances of Chinese culture and background. The goal of this study is to evaluate the level of spiritual needs and influencing factors in Chinese stroke patients and to explore the mediating role and pathways of these variables on spiritual needs. Methods From August 2022 to January 2023, we conducted a cross-sectional questionnaire survey of 422 stroke patients in the affiliated hospitals of Hunan University of Chinese Medicine in Changsha Province by cluster sampling. We measured the patient’s spiritual needs, quality of life, anxiety and depression levels, and family support using the Spiritual Needs Questionnaire (SPNQ), the MOS36 item Short Form Health Survey (SF-36), the Hospital Anxiety and Depression Scale (HADS), and the Family Support Self Rating Scale (PSS-Fa). We used the General Information Questionnaire to gain insight into the sociodemographic characteristics of the patients. Nonparametric tests and multiple linear regression models were used to analyze the independent relationship between spiritual needs and quality of life, anxiety, depression, and family support. The mediation model in AMOS 24.0 software was used to analyze the mediating role among the five variables. Results The score of spiritual needs of people with stroke included in this study was 37 points [IQR 33 to 40)]. The influencing factors of spiritual needs included primary economic sources for disease-related expenditures ( p  = 0.044), number of stroke occurrences ( p  = 0.001), duration of illness ( p  = 0.023), activities of daily living ( p  = 0.006), depression scores( p  = 0.034), and family support scores( p  = 0.008). Anxiety (β = 0.347, p  = 0.004), depression (β = 0.368, p  = 0.005), and family support (β = 0.167, p  = 0.023) had directly or indirectly affected the spiritual needs of people with stroke. Quality of life (β=-0.202, p  = 0.017) had a direct effect on spiritual needs. Conclusions The spiritual needs of people with stroke were at an intermediate level. Our findings highlight that the SPNQ score is associated with anxiety, depression, quality of life, and family support. Therefore, nurses should identify the spiritual needs of patients and provide them with effective and comprehensive spiritual care by reducing negative emotions and enhancing social support, promoting the development and progress of spiritual care in China. This study offers a theoretical basis for the spiritual care of clinical people with stroke and constructing a stroke spiritual care model.

SignificanceThe steric activity of the lone pair electrons of Pb2+-containing compounds distorts the crystal structure and produces exotic physical properties. In ferroelectric PbTiO3 and PbVO3, the lone-pair electrons hybridizing with the oxygen lead to polarized MO6 octahedra. In PbRuO3, the hybridization induces unprecedented Pb-Ru bonds at high pressure. The sterochemical effect in PbCrO3 makes Pb bond with oxygen without a long-range periodicity. Under the influence of displaced Pb2+, Cr4+ undergoes a charge disproportionation that opens up a gap. In contrast to the pressure effect on PbTiO3 and PbRuO3, pressure restores the undistorted perovskite structure in PbCrO3. This result implies that the sterochemical effect of Pb2+ in a perovskite depends sensitively on the number and energy of the d electrons. The perovskite PbCrO3 is an antiferromagnetic insulator. However, the fundamental interactions leading to the insulating state in this single-valent perovskite are unclear. Moreover, the origin of the unprecedented volume drop observed at a modest pressure of P = 1.6 GPa remains an outstanding problem. We report a variety of in situ pressure measurements including electron transport properties, X-ray absorption spectrum, and crystal structure study by X-ray and neutron diffraction. These studies reveal key information leading to the elucidation of the physics behind the insulating state and the pressure-induced transition. We argue that a charge disproportionation 3Cr4+ → 2Cr3+ + Cr6+ in association with the 6s-p hybridization on the Pb2+ is responsible for the insulating ground state of PbCrO3 at ambient pressure and the charge disproportionation phase is suppressed under pressure to give rise to a metallic phase at high pressure. The model is well supported by density function theory plus the correlation energy U (DFT+U) calculations.

The paper systematically study topological superconducting (TSC) phases in monolayer NbSe2 by constructing the hybrid paring tight-binding model of mixing on-site s-wave pairing (ps) and long-range pairing (pA1) for the first time. We observe rich phases with both fixed and sensitive Chern numbers (CNs) depending on the chemical potential (μ) and out-of-plane magnetic field (Vz). As pA1 increases, the TSC phase manifests matching and mismatching features according to whether the CNs match with the number of topological edge states (TESs). Strikingly, the introduction of long-range pairing significantly reduces the critical Vz to form TSC phases compared with the pure on-site s-wave paring. Moreover, the TSC phases can be modulated even at Vz = 0 under appropriate μ and pA1, which is identified by the robust TESs of ribbons. Additionally, the long-range pairing influences the hybridization of bulk and edge states, resulting in a matching/mismatching bulk-boundary correspondence with localized/oscillating TESs on the ribbons. Our findings are helpful for realizing TSC states through compressive strain experimentally to strengthen long-range pairings, as well as designing and regulating TSC materials.

Nanocluster structures It is difficult to determine the three-dimensional structure of ultrasmall nanoparticles as they are unstable and tend to interact with any incident electron beams used to examine them. Now, using aberration-corrected scanning transmission electron microscopy coupled with imaging simulation, the size, shape, orientation and atomic arrangement of specially prepared size-selected gold nanoclusters have been determined to single-atom resolution. The particles were preformed in the gas phase and soft-landed on an amorphous carbon substrate. These materials are of interest for catalytic and biological applications. Aberration-corrected scanning transmission electron microscopy, coupled with simple imaging simulation, is used to determine with atomic resolution the size, three-dimensional shape, orientation and atomic arrangement of size-selected gold nanoclusters that are preformed in the gas phase and soft-landed on an amorphous carbon substrate. An unambiguous determination of the three-dimensional structure of nanoparticles is challenging 1 . Electron tomography requires a series of images taken for many different specimen orientations 2 . This approach is ideal for stable and stationary structures 3 . But ultrasmall nanoparticles are intrinsically structurally unstable and may interact with the incident electron beam 4 , 5 , 6 , constraining the electron beam density that can be used and the duration of the observation. Here we use aberration-corrected scanning transmission electron microscopy 7 , coupled with simple imaging simulation, to determine with atomic resolution the size, three-dimensional shape, orientation and atomic arrangement of size-selected gold nanoclusters that are preformed in the gas phase and soft-landed on an amorphous carbon substrate. The structures of gold nanoclusters containing 309±6 atoms can be identified with either Ino-decahedral, cuboctahedral or icosahedral geometries. Comparison with theoretical modelling of the system suggests that the structures are consistent with energetic considerations. The discovery that nanoscale gold particles function as active and selective catalysts for a variety of important chemical reactions has provoked much research interest in recent years 8 , 9 , 10 , 11 , 12 . We believe that the detailed structure information we provide will help to unravel the role of these nanoclusters in size- and structure-specific catalytic reactions 11 , 12 . We note that the technique will be of use in investigations of other supported ultrasmall metal cluster systems.

Achieving transgene integration into preselected genomic sites is currently one of the central tasks in stem cell gene therapy. A strategy to mediate such targeted integration involves site-specific endonucleases. Two genomic sites within the MBS85 and chemokine ( C-C motif ) receptor 5 ( CCR5 ) genes (AAVS1 and CCR5 zinc-finger nuclease (CCR5-ZFN) sites, respectively) have recently been suggested as potential target regions for integration as their disruption has no functional consequence. We hypothesized that efficient transgene integration maybe affected by DNA accessibility of endonucleases and therefore studied the transcriptional and chromatin status of the AAVS1 and CCR5 sites in eight human induced pluripotent stem (iPS) cell lines and pooled CD34+ hematopoietic stem cells (HSCs). Matrix chromatin immunoprecipitation (ChIP) assays demonstrated that the CCR5 site and surrounding regions possessed a predominantly closed chromatin configuration consistent with its transcriptional inactivity in these cell types. In contrast, the AAVS1 site was located within a transcriptionally active region and exhibited an open chromatin configuration in both iPS cells and HSCs. To show that the AAVS1 site is readily amendable to genome modification, we expressed Rep78, an AAV2-derived protein with AAVS1-specific endonuclease activity, in iPS cells after adenoviral gene transfer. We showed that Rep78 efficiently associated with the AAVS1 site and triggered genome modifications within this site. On the other hand, binding to and modification of the CCR5-ZFN site by a ZFN was relatively inefficient. Our data suggest a critical influence of chromatin structure on efficacy of site-specific endonucleases used for genome editing.

Controlled growth of far-from-equilibrium-shaped nanoparticles with size selection is essential for the exploration of their unique physical and chemical properties. Shape control by wet-chemistry preparation methods produces surfactant-covered surfaces with limited understanding due to the complexity of the processes involved. Here, we report the controlled production and transformation of octahedra to tetrahedra of size-selected platinum nanocrystals with clean surfaces in an inert gas environment. Molecular dynamics simulations of the growth reveal the key symmetry-breaking atomic mechanism for this autocatalytic shape transformation, confirming the experimental conditions required. In-situ heating experiments demonstrate the relative stability of both octahedral and tetrahedral Pt nanocrystals at least up to 700 °C and that the extended surface diffusion at higher temperature transforms the nanocrystals into equilibrium shape. Tetrahedral nanocrystals are out-of-equilibrium structures whose growth mechanism is a long-standing open problem. Here, the authors show that pure Pt tetrahedral nanocrystals grow in the gas phase and single out the defect-mediated mechanism leading to the symmetry-breaking for tetrahedral growth.

Modular charging is an advanced technique designed to meet the requirements of auto-loading artillery, whereby granular propellants are stored within modular cartridges that are loaded into the gun chamber. This study employed an extended coupled computational fluid dynamics-discrete element method (CFD-DEM) approach to investigate the gas-particle flow within modular charges. After model validation, we analyzed the distribution characteristics, velocity, coordination number, and orientation of cylindrical pellets in a simulator chamber. Four different loading positions for modular cartridges were examined to assess their impact on particle distribution. Numerical simulations revealed a combination of gentle, horizontal, and steep slopes in the particle distribution. The maximum particle velocity experienced a rapid increase during the initial phase, followed by a zigzag decline after reaching its peak. High-coordination number particles tended to accumulate primarily in the middle layer of steep accumulation. Additionally, the particles exhibited an inverted V-shape orientation range from 0° to 180°, suggesting their tendency to assume upright positions. This established model significantly enhanced our understanding of particle distribution following module cartridge rupture and provided valuable guidance for optimizing the design of large-caliber artillery charges.