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Energy efficiency is motivating the search for new high-temperature (high-T) metals. Some new body-centered-cubic (BCC) random multicomponent “high-entropy alloys (HEAs)” based on refractory elements (Cr-Mo-Nb-Ta-V-W-Hf-Ti-Zr) possess exceptional strengths at high temperatures but the physical origins of this outstanding behavior are not known. Here we show, using integrated in-situ neutron-diffraction (ND), high-resolution transmission electron microscopy (HRTEM), and recent theory, that the high strength and strength retention of a NbTaTiV alloy and a high-strength/low-density CrMoNbV alloy are attributable to edge dislocations. This finding is surprising because plastic flows in BCC elemental metals and dilute alloys are generally controlled by screw dislocations. We use the insight and theory to perform a computationally-guided search over 10 7 BCC HEAs and identify over 10 6 possible ultra-strong high-T alloy compositions for future exploration. The strength in BCC high-entropy alloys is associated with the type of mobile dislocations. Here the authors demonstrate by means of an ample array of experimental techniques that edge dislocations can control the strength of BCC high-entropy alloys.

Exploitation of the oxidation behaviour in an environmentally sensitive semiconductor is significant to modulate its electronic properties and develop unique applications. Here, we demonstrate a native oxidation-inspired InSe field-effect transistor as an artificial synapse in device level that benefits from the boosted charge trapping under ambient conditions. A thin InO x layer is confirmed under the InSe channel, which can serve as an effective charge trapping layer for information storage. The dynamic characteristic measurement is further performed to reveal the corresponding uniform charge trapping and releasing process, which coincides with its surface-effect-governed carrier fluctuations. As a result, the oxide-decorated InSe device exhibits nonvolatile memory characteristics with flexible programming/erasing operations. Furthermore, an InSe-based artificial synapse is implemented to emulate the essential synaptic functions. The pattern recognition capability of the designed artificial neural network is believed to provide an excellent paradigm for ultra-sensitive van der Waals materials to develop electric-modulated neuromorphic computation architectures. Developing efficient memory and artificial synaptic systems based on environmentally sensitive van der Waals materials remains a challenge. Here, the authors present a native oxidation-inspired InSe field-effect transistor that benefits from a boosted charge trapping behavior under ambient conditions.

Monolayer transition metal dichalcogenides, such as MoS 2 and WSe 2 , have been known as direct gap semiconductors and emerged as new optically active materials for novel device applications. Here we reexamine their direct gap properties by investigating the strain effects on the photoluminescence of monolayer MoS 2 and WSe 2 . Instead of applying stress, we investigate the strain effects by imaging the direct exciton populations in monolayer WSe 2 –MoS 2 and MoSe 2 –WSe 2 lateral heterojunctions with inherent strain inhomogeneity. We find that unstrained monolayer WSe 2 is actually an indirect gap material, as manifested in the observed photoluminescence intensity–energy correlation, from which the difference between the direct and indirect optical gaps can be extracted by analyzing the exciton thermal populations. Our findings combined with the estimated exciton binding energy further indicate that monolayer WSe 2 exhibits an indirect quasiparticle gap, which has to be reconsidered in further studies for its fundamental properties and device applications. Monolayer transition metal dichalcogenides have so far been thought to be direct bandgap semiconductors. Here, the authors revisit this assumption and find that unstrained monolayer WSe 2 is an indirect-gap material, as evidenced by the observed photoluminescence intensity-energy correlation.

Alpha/beta hydrolase domain-containing protein 5 (ABHD5) is a highly conserved protein that regulates various lipid metabolic pathways via interactions with members of the perilipin (PLIN) and Patatin-like phospholipase domain-containing protein (PNPLA) protein families. Loss of function mutations in ABHD5 result in Chanarin–Dorfman Syndrome (CDS), characterized by ectopic lipid accumulation in numerous cell types and severe ichthyosis. Recent data demonstrates that ABHD5 is the target of synthetic and endogenous ligands that might be therapeutic beneficial for treating metabolic diseases and cancers. However, the structural basis of ABHD5 functional activities, such as protein–protein interactions and ligand binding is presently unknown. To address this gap, we constructed theoretical structural models of ABHD5 by comparative modeling and topological shape analysis to assess the spatial patterns of ABHD5 conformations computed in protein dynamics. We identified functionally important residues on ABHD5 surface for lipolysis activation by PNPLA2, lipid droplet targeting and PLIN-binding. We validated the computational model by examining the effects of mutating key residues in ABHD5 on an array of functional assays. Our integrated computational and experimental findings provide new insights into the structural basis of the diverse functions of ABHD5 as well as pathological mutations that result in CDS.

Free‐standing gallium nitride has been prepared using various methods; however, the removal of the original substrate is still challenging with low success rates. In this work, 2‐inch free‐standing GaN films are obtained by direct growth on a fluoro phlogopite mica by hydride vapor‐phase epitaxy. Depending on the van der Waals (vdW) interaction between GaN and mica, the effect of the significant lattice mismatch is effectively reduced; thus, enabling the production of a high‐quality wafer‐scale GaN film on mica. The vdW‐induced cracks at GaN–mica interface are found to be initiated near the interface so that GaN can easily separate from mica during rapid cooling. Owing to the hydrophilic nature of mica, the residual GaN on the mica can be lifted off by following deionized water treatment, and the mica substrate can be repeatedly used to grow free‐standing GaN films. The self‐separated GaN films grown on both pristine and used mica substrates are single crystallinity and strain‐free. Additionally, a fully functional ultraviolet light‐emitting diode is demonstrated to show that the self‐separated GaN films are of device quality. The proposed approach achieves epitaxial growth of wafer‐scale single‐crystalline GaN on 2D materials and provides a new substrate option in the technology of III‐V materials. A self‐separation technique for generating thick GaN films on a 2D material substrate is demonstrated for the first time. The reusability of mica substrates by repeatedly growing thick GaN films on the same substrate is shown. Moreover, ultraviolet light‐emitting diodes on self‐separated thick GaN films, demonstrating the device quality of these thick GaN films are fabricated.

Van der Waals heterobilayers of transition metal dichalcogenides with spin–valley coupling of carriers in different layers have emerged as a new platform for exploring spin/valleytronic applications. The interlayer coupling was predicted to exhibit subtle changes with the interlayer atomic registry. Manually stacked heterobilayers, however, are incommensurate with the inevitable interlayer twist and/or lattice mismatch, where the properties associated with atomic registry are difficult to access by optical means. Here, we unveil the distinct polarization properties of valley-specific interlayer excitons using epitaxially grown, commensurate WSe 2 /MoSe 2 heterobilayers with well-defined (AA and AB) atomic registry. We observe circularly polarized photoluminescence from interlayer excitons, but with a helicity opposite to the optical excitation. The negative circular polarization arises from the quantum interference imposed by interlayer atomic registry, giving rise to distinct polarization selection rules for interlayer excitons. Using selective excitation schemes, we demonstrate the optical addressability for interlayer excitons with different valley configurations and polarization helicities. The interlayer coupling in van der Waals heterostructures is sensitive to the interlayer atomic registry. Here, the authors investigate the polarisation properties of epitaxially grown, commensurate WSe 2 /MoSe 2 heterobilayers with well-defined atomic registry, and observe negative, circularly polarized photoluminescence from interlayer excitons.

Researchers have long been seeking multifunctional materials that can be adopted for next-generation nanoelectronics, and which, hopefully, are compatible with current semiconductor processing for further integration. Along this vein, complex oxides have gained numerous attention due to their versatile functionalities. Despite the fact that unbounded potential of complex oxides has been examined over the past years, one of the major challenges lies in the direct integration of these functional oxides onto existing devices or targeted substrates that are inherently incompatible in terms of oxide growth. To fulfill this goal, freestanding processes have been proposed, in which wet etching of inserted sacrificial layers is regarded as one of the most efficient ways to obtain epitaxial high-quality thin films. In this study, we propose using an alternative oxide, YBa2Cu3O7 (YCBO), as a sacrificial layer, which can be easily dissolved in light hydrochloric acid in a more efficient way, while protecting selected complex oxides intact. The high epitaxial quality of the selected complex oxide before and after freestanding process using YBCO as a sacrificial layer is comprehensively studied via a combination of atomic force microscopy, X-ray diffraction, transmission electron microscopy, and electrical transports. This approach enables direct integration of complex oxides with arbitrary substrates and devices and is expected to offer a faster route towards the development of low-dimensional quantum materials.

Nociceptors are key sensory receptors that transmit warning signals to the central nervous system in response to painful stimuli. This fundamental process is emulated in an electronic device by developing a novel artificial nociceptor with an ultrathin, nonstoichiometric gallium oxide (GaOx)‐silicon oxide heterostructure. A large‐area 2D‐GaOx film is printed on a substrate through liquid metal printing to facilitate the production of conductive filaments. This nociceptive structure exhibits a unique short‐term temporal response following stimulation, enabling a facile demonstration of threshold‐switching physics. The developed heterointerface 2D‐GaOx film enables the fabrication of fast‐switching, low‐energy, and compliance‐free 2D‐GaOx nociceptors, as confirmed through experiments. The accumulation and extrusion of Ag in the oxide matrix are significant for inducing plastic changes in artificial biological sensors. High‐resolution transmission electron microscopy and electron energy loss spectroscopy demonstrate that Ag clusters in the material dispersed under electrical bias and regrouped spontaneously when the bias is removed owing to interfacial energy minimization. Moreover, 2D nociceptors are stable; thus, heterointerface engineering can enable effective control of charge transfer in 2D heterostructural devices. Furthermore, the diffusive 2D‐GaOx device and its Ag dynamics enable the direct emulation of biological nociceptors, marking an advancement in the hardware implementation of artificial human sensory systems. An artificial nociceptor is developed utilizing ultrathin 2D‐GaOx, featuring low power consumption and quick switching. Electron energy loss spectroscopy reveals that, when a threshold bias is applied, Ag atoms disperse in the active layer, and then reassemble after bias removal, in order to reduce interfacial energy. The heterointerfaced 2D‐GaOx nociceptor ensures stable, precise charge transfer control, enabling long‐term atmospheric use.

Aims and Objectives. The purpose of this study was to investigate the prevalence of job burnout among Taiwanese nurses, specifically exploring the mediating role of workplace social support in the association between nurses’ stressors and this burnout. Background. Nurses confront high-stress, high-stakes work environments due to evolving disease patterns and growing healthcare needs. The nurse-patient ratio in Taiwan is higher than in other countries, necessitating effective strategies to mitigate nurse burnout and enhance the quality of patient care. Design. A cross-sectional study design was employed. Methods. From January to April 2019, 500 nurses were recruited from a medical center in Kaohsiung City, southern Taiwan. Participants completed a questionnaire addressing workplace social support, stressors faced by nurses, and job burnout. Data were analyzed using descriptive statistics, one-way analysis of variance, t-test evaluations, Pearson’s correlation analyses, and a structural equation model with maximum likelihood estimation. Results. The findings revealed that a portion of nurses experienced high rates of personal burnout (7.20%), work-related burnout (5.00%), and client-related burnout (4.80%). The relationships among workplace social support, nurses’ stressors, and job burnout were all substantial, exhibiting correlation coefficients ranging from −0.318 to 0.828. The direct effect of nurse stress on job burnout was 0.551, comprising 90.7% of the cumulative effect. In contrast, the indirect effect of nurse stress on job burnout, considering workplace social support, amounted to 9.3% of the total effect, with a value of 0.056. Conclusions. The study underscored the importance of addressing job burnout among nurses in Taiwan. Workplace social support may function as a mediating factor in the relationship between nurses’ stressors and job burnout. Implications for Nursing Management. The results suggest that healthcare administrators should prioritize workplace social support initiatives. These efforts could help identify and address nurses’ stressors, promote work-life balance, and reduce nurse-patient ratios and work overload.

The mechanical behavior and microstructural evolution of a BCC‐phase NbTaTiV refractory multi‐principal element alloy (RMPEA) is studied over a wide range of strain rates (10−3 to 103 s−1) and temperatures (room temperature to 850 °C). The mechanical property of present RMPEA shows less strain‐rate dependence and strong resistance to softening at high temperatures. Under high strain‐rate loading, the formation of thin type‐I twins is observed, which could lead to an increase in strain‐hardening rates. However, this hardening mechanism competes with adiabatic heating effects, resulting in the deterrence of strain‐hardening behaviors. In contrast, substantial strain‐hardening occurs at cryogenic temperatures due to the formation of twins, which act as stronger barriers to dislocation motion and interact with each other. To further understand the different strain‐hardening behaviors, density functional theory (DFT) calculations predict relatively low stacking fault energies and high twinning stress for the NbTaTiV RMPEA. Exceptional mechanical stability of refractory multi‐principal element alloy (RMPEA) across various strain‐rates and temperature is studied through multiscale experiments coupled with theoretical calculations. This stability originates from competition between twinning and adiabatic heating during dynamic deformation, contributed from severe lattice distortion and edge dislocation strengthening. However, cryogenic testing still shows pronounced strain hardening from abundant twins.