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Amidst the burgeoning information age, the rapid development of artificial intelligence-generated content (AIGC) has brought forth challenges regarding information authenticity. The proliferation of distorted information significantly impacts users negatively. This study aims to systematically categorize distorted information within AIGC, delve into its internal characteristics, and provide theoretical guidance for its management. Utilizing ChatGPT as a case study, we conducted empirical content analysis on 243 instances of distorted information collected, comprising both questions and answers. Three coders meticulously interpreted each instance of distorted information, encoding error points based on a predefined coding scheme and categorizing them according to error type. Our objective was to refine and validate the distorted information category list derived from the review through multiple rounds of pre-coding and test coding, thereby yielding a comprehensive and clearly delineated category list of distorted information in AIGC. The findings identified 8 first-level error types: “Overfitting”; “Logic errors”; “Reasoning errors”; “Mathematical errors”; “Unfounded fabrication”; “Factual errors”; “Text output errors”; and “Other errors”, further subdivided into 31 second-level error types. This classification list not only lays a solid foundation for studying risks associated with AIGC but also holds significant practical implications for helping users identify distorted information and enabling developers to enhance the quality of AI-generated tools.

Electrocatalysts of the hydrogen evolution and oxidation reactions (HER and HOR) are of critical importance for the realization of future hydrogen economy. In order to make electrocatalysts economically competitive for large-scale applications, increasing attention has been devoted to developing noble metal-free HER and HOR electrocatalysts especially for alkaline electrolytes due to the promise of emerging hydroxide exchange membrane fuel cells. Herein, we report that interface engineering of Ni 3 N and Ni results in a unique Ni 3 N/Ni electrocatalyst which exhibits exceptional HER/HOR activities in aqueous electrolytes. A systematic electrochemical study was carried out to investigate the superior hydrogen electrochemistry catalyzed by Ni 3 N/Ni, including nearly zero overpotential of catalytic onset, robust long-term durability, unity Faradaic efficiency, and excellent CO tolerance. Density functional theory computations were performed to aid the understanding of the electrochemical results and suggested that the real active sites are located at the interface between Ni 3 N and Ni. Efficient hydrogen production and utilization materials will be crucial in order to compete with fossil fuel technologies. Here, authors report nickel and nickel nitride interfaces as effected catalysts for hydrogen evolution and oxidation in water.

One-photon-absorbing photosensitizers are commonly used in homogeneous photocatalysis which require the absorption of ultraviolet (UV) /visible light to populate the desired excited states with adequate energy and lifetime. Nevertheless, the limited penetration depth and competing absorption by organic substrates of UV/visible light calls upon exploring the utilization of longer-wavelength irradiation, such as near-infrared light (λ irr  > 700 nm). Despite being found applications in photodynamic therapy and bioimaging, two-photon absorption (TPA), the simultaneous absorption of two photons by one molecule, has been rarely explored in homogeneous photocatalysis. Herein, we report a group of ruthenium polypyridyl complexes possessing TPA capability that can drive a variety of organic transformations upon irradiation with 740 nm light. We demonstrate that these TPA ruthenium complexes can operate in an analogous manner as one-photon-absorbing photosensitizers for both energy-transfer and photoredox reactions, as well as function in concert with a transition metal co-catalyst for metallaphotoredox C–C coupling reactions. The field of homogeneous metal- and photocatalysis typically uses one-photon-absorbing photosensitizers, which are highly functional, but require higher-energy light. Here the authors report a group of ruthenium polypyridyl complexes possessing two-photon-absorption capabilities, active with irradiation with lower-energy (740 nm) light.

Single-cell RNA sequencing (scRNA-seq) has revolutionized transcriptomic studies by providing unprecedented cellular and molecular throughputs, but spatial information of individual cells is lost during tissue dissociation. While imaging-based technologies such as in situ sequencing show great promise, technical difficulties currently limit their wide usage. Here we hypothesize that cellular spatial organization is inherently encoded by cell identity and can be reconstructed, at least in part, by ligand-receptor interactions, and we present CSOmap, a computational tool to infer cellular interaction de novo from scRNA-seq. We show that CSOmap can successfully recapitulate the spatial organization of multiple organs of human and mouse including tumor microenvironments for multiple cancers in pseudo-space, and reveal molecular determinants of cellular interactions. Further, CSOmap readily simulates perturbation of genes or cell types to gain novel biological insights, especially into how immune cells interact in the tumor microenvironment. CSOmap can be a widely applicable tool to interrogate cellular organizations based on scRNA-seq data for various tissues in diverse systems.

The broad employment of water electrolysis for hydrogen (H 2 ) production is restricted by its large voltage requirement and low energy conversion efficiency because of the sluggish oxygen evolution reaction (OER). Herein, we report a strategy to replace OER with a thermodynamically more favorable reaction, the partial oxidation of formaldehyde to formate under alkaline conditions, using a Cu 3 Ag 7 electrocatalyst. Such a strategy not only produces more valuable anodic product than O 2 but also releases H 2 at the anode with a small voltage input. Density functional theory studies indicate the H 2 C(OH)O intermediate from formaldehyde hydration can be better stabilized on Cu 3 Ag 7 than on Cu or Ag, leading to a lower C-H cleavage barrier. A two-electrode electrolyzer employing an electrocatalyst of Cu 3 Ag 7 (+)||Ni 3 N/Ni(–) can produce H 2 at both anode and cathode simultaneously with an apparent 200% Faradaic efficiency, reaching a current density of 500 mA/cm 2 with a cell voltage of only 0.60 V. Water electrolysis typically requires a large voltage input and produces H 2 only at the cathode. Here the authors present a strategy of coupling formaldehyde oxidation with water reduction and report H 2 production at both anode and cathode with small voltage inputs.

Inorganic solids are an important class of catalysts that often derive their activity from sparse active sites that are structurally distinct from the inactive bulk. Rationally optimizing activity is therefore beholden to the challenges in studying these active sites in molecular detail. Here, we report a molecule that mimics the structure of the proposed triangular active edge site fragments of molybdenum disulfide (MoS₂ ), a widely used industrial catalyst that has shown promise as a low-cost alternative to platinum for electrocatalytic hydrogen production. By leveraging the robust coordination environment of a pentapyridyl ligand, we synthesized and structurally characterized a well-defined Mo lv -disulfide complex that, upon electrochemical reduction, can catalytically generate hydrogen from acidic organic media as well as from acidic water.

The surface of the iron-based superconductor FeTe 0.55 Se 0.45 has been identified as a potential topological superconductor and is expected to host exotic quasiparticles called the Majorana bound states (MBSs). Wang et al. looked for signatures of MBSs in this material by using scanning tunneling spectroscopy on the vortex cores formed by the application of a magnetic field. In addition to conventional states, they observed the characteristic zero-bias peaks associated with MBSs and were able to distinguish between the two, owing to the favorable ratios of energy scales in the system. Science , this issue p. 333 Scanning tunneling spectroscopy reveals signatures of Majorana bound states on the surface of FeTe 1− x Se x . The search for Majorana bound states (MBSs) has been fueled by the prospect of using their non-Abelian statistics for robust quantum computation. Two-dimensional superconducting topological materials have been predicted to host MBSs as zero-energy modes in vortex cores. By using scanning tunneling spectroscopy on the superconducting Dirac surface state of the iron-based superconductor FeTe 0.55 Se 0.45 , we observed a sharp zero-bias peak inside a vortex core that does not split when moving away from the vortex center. The evolution of the peak under varying magnetic field, temperature, and tunneling barrier is consistent with the tunneling to a nearly pure MBS, separated from nontopological bound states. This observation offers a potential platform for realizing and manipulating MBSs at a relatively high temperature.

Migrasomes are recently discovered cellular organelles that form as large vesicle-like structures on retraction fibres of migrating cells. While the process of migrasome formation has been described before, the molecular mechanism underlying migrasome biogenesis remains unclear. Here, we propose that the mechanism of migrasome formation consists of the assembly of tetraspanin- and cholesterol-enriched membrane microdomains into micron-scale macrodomains, which swell into migrasomes. The major finding underlying the mechanism is that tetraspanins and cholesterol are necessary and sufficient for migrasome formation. We demonstrate the necessity of tetraspanins and cholesterol via live-cell experiments, and their sufficiency by generating migrasome-like structures in reconstituted membrane systems. We substantiate the mechanism by a theoretical model proposing that the key factor driving migrasome formation is the elevated membrane stiffness of the tetraspanin- and cholesterol-enriched macrodomains. Finally, the theoretical model was quantitatively validated by experimental demonstration of the membrane-stiffening effect of tetraspanin 4 and cholesterol. Yu and colleagues report that migrasome formation depends on tetraspanin and cholesterol. Macrodomains formed by clustering of tetraspanin- and cholesterol-enriched membrane domains swell to generate migrasomes.

TLR4 signaling plays key roles in the innate immune response to microbial infection. Innate immune cells encounter different mechanical cues in both health and disease to adapt their behaviors. However, the impact of mechanical sensing signals on TLR4 signal-mediated innate immune response remains unclear. Here we show that TLR4 signalling augments macrophage bactericidal activity through the mechanical sensor Piezo1. Bacterial infection or LPS stimulation triggers assembly of the complex of Piezo1 and TLR4 to remodel F-actin organization and augment phagocytosis, mitochondrion-phagosomal ROS production and bacterial clearance and genetic deficiency of Piezo1 results in abrogation of these responses. Mechanistically, LPS stimulates TLR4 to induce Piezo1-mediated calcium influx and consequently activates CaMKII-Mst1/2-Rac axis for pathogen ingestion and killing. Inhibition of CaMKII or knockout of either Mst1/2 or Rac1 results in reduced macrophage bactericidal activity, phenocopying the Piezo1 deficiency. Thus, we conclude that TLR4 drives the innate immune response via Piezo1 providing critical insight for understanding macrophage mechanophysiology and the host response. Innate immune cells respond to a number of environmental cues including TLR signalling. Here the authors implicate mechanical sensor Piezo1 in the TLR4 mediated host response to bacterial infection and implicate it in the enhancement of macrophage mediated host response.

Heat-shock transcription factor 1 (HSF1) orchestrates the fast and vast cellular response to heat shock through increased expression of heat-shock proteins. However, how HSF1 rapidly and reversibly regulates transcriptional reprogramming remains poorly defined. Here by combining super-resolution imaging, in vitro reconstitution and high-throughput sequencing, we reveal that HSF1 forms small nuclear condensates via liquid–liquid phase separation at heat-shock-protein gene loci and enriches multiple transcription apparatuses through co-phase separation to promote the transcription of target genes. Furthermore, the phase-separation capability of HSF1 is fine-tuned through phosphorylation at specific sites within the regulatory domain. Last, we discovered that HSP70 disperses HSF1 condensates to attenuate transcription following the cessation of heat shock and further prevents the gel-like phase transition of HSF1 under extended heat-shock stress. Our work reveals an inducible and reversible phase-separation feedback mechanism for dynamic regulation of HSF1 activity to drive the transcriptional response and maintain protein homeostasis during acute stress. Zhang, Shao and coworkers report that HSF1 forms small condensates at its target gene loci to promote their transcription during acute heat stress. The produced HSP70 proteins in turn disperse HSF1 condensates to shut off the heat-shock response.