In confined mesoscopic spaces, the unraveling of catalytic mechanism with complex mass transfer and adsorption processes, such as reactant enrichment is a great challenge. In this study, a hollow nanoarchitecture MnOx encapsulated Pt nanoparticles (NPs) was designed as nanoreactors to investigate the reactant enrichment in a mesoscopic hollow void. By employing advanced characterization techniques, we found that the reactant enrichment behavior is derived from directional diffusion of reactant driven through local concentration gradient, and increased amount of reactant. Combining experimental results with density functional theory (DFT) calculations, the superior cinnamyl alcohol (COL) selectivity originates from the selective adsorption of cinnamaldehyde (CAL) and the rapid formation and desorption of COL in the MnOx shell. The superb performance of 95% CAL conversion and 95% COL selectivity is obtained at only 0.5 MPa H2 and 40 min. Our findings showcase that a rationally designed nanoreactor could boost catalytic performance in chemoselective hydrogenation, which can be of great aid and potential in various application scenarios.

Achieving carbon neutrality in the chemical industry necessitates a green and efficient transformation. Working together, industry and academia hold the key to developing clean chemical processes, which is crucial.

The underlying principle of the unique dynamic adaptive adhesion capability of a rock-climbing fish (Beaufortia kweichowensis) that can resist the pull-off force of 1000 times its weight while achieving simultaneous fast sliding (7.83 body lengths per second) remains a mystery in the open literature. This adhesion-sliding ability has long been sought for underwater robots. However, strong surface adhesion and fast sliding appear to contradict each other due to the need for high surface contact stress. The skillfully balanced mechanism for tight-surface adhesion and fast sliding of the rock-climbing fish is disclosed in this work. The Stefan force (0.1 mN/mm2) generated by micro-setae on pectoral fins and ventral fins leads to 70 N/m2 adhesion force through conforming the overall body of the fish to a surface to form a sealing chamber. The pull-off force would be neutralized simultaneously due to the negative pressure caused by the volumetric change of the chamber. The rock-climbing fish's micro-setae hydrodynamic interaction and sealing suction cup work cohesively to contribute to low friction and high pull-off force resistance and can therefore slide rapidly while clinging to the surface. Inspired by the unique mechanism, an underwater robot is developed with incorporated structures that mimic the functionality of the rock-climbing fish by fabricating a micro-setae array and attaching them to a soft self-adaptive chamber, which demonstrates similar superiorities over conventional ones in terms of balancing underwater tightness adhesion and fast sliding.

Multiple morphological abnormalities of the sperm flagella (MMAF) is one of the major causes of male infertility and is characterized by multiple defects. In this study, we found that the coiled-coil domain-containing 189 (Ccdc189) gene was predominantly expressed in mouse testes and that inactivation of the Ccdc189 gene caused male infertility. Histological studies revealed that most sperm from Ccdc189-deficient mice carried coiled, curved, or short flagella, which are typical MMAF phenotypes. Immunoelectron microscopy showed that the CCDC189 protein was located at the radial spoke of the first peripheral microtubule doublets (MTDs) in the sperm axoneme. A CCDC189-interacting protein, CABCOCO1, was discovered via coimmunoprecipitation and mass spectrometry, and inactivation of Cabcoco1 caused malformation of sperm flagella, which was consistent with findings obtained with Ccdc189-deficient mice. Further studies revealed that inactivation of CCDC189 caused downregulation of CABCOCO1 protein expression and that both CCDC189 and CABCOCO1 interacted with the radial spoke-specific protein RSPH1 and intraflagellar transport proteins. This study demonstrated that Ccdc189 is a radial spoke-associated protein and is involved in sperm flagellum formation through its interactions with CABCOCO1 and intraflagellar transport proteins.

The Intelligent Earth (iEarth) framework, composed of four major themes: iEarth data, science, analytics, and decision, is proposed to define and build an interdisciplinary and synergistic framework for research, practice, and education that simultaneously safeguards the sustainable development of our living planet.

Fabricating highly crystalline macroscopic films with extraordinary electrical and thermal conductivities from graphene sheets is essential for applications in electronics, telecommunications, and thermal management. High-temperature graphitization is the only way known to date for the crystallization of all types of carbon materials, where defects are gradually removed with increasing the temperature. However, when using graphene materials as precursors including graphene oxide, reduced graphene oxide and pristine graphene, even a long-term graphitization at 3000°C can only produce graphene films with small grain sizes and abundant structural disorders, which limit their conductivities. Here, we show that high-temperature defects substantially accelerate the grain growth and ordering of graphene films during graphitization, enabling ideal AB stacking as well as over 100, 64 and 28 times improvements in grain size, electrical and thermal conductivities, respectively, from 2000 to 3000°C. This process is realized by nitrogen doping, which retards the lattice restoration of defective graphene, retaining abundant defects such as vacancies, dislocations and grain boundaries in graphene films at high temperature. With this approach, a highly ordered crystalline graphene film similar as highly oriented pyrolytic graphite is fabricated, whose electrical and thermal conductivities (∼2.0 × 104 S cm−1; ∼1.7 × 103 W m−1 K−1) are improved by ∼6 and 2 times, respectively, compared to those of the graphene films fabricated by graphene oxide. Such graphene film also exhibits a superhigh electromagnetic interference shielding effectiveness of ∼90 dB at a thickness of 10 μm, outperforming all the synthetic materials of comparable thickness including MXene films. This work not only paves the way for the technological applications of highly conductive graphene films but also provides a general strategy to efficiently improve the synthesis and properties of other carbon materials such as graphene fibers, carbon nanotube fibers, carbon fibers, polymer-derived graphite, and highly oriented pyrolytic graphite.

Flexible piezoelectric materials withstanding large deformation play key roles in flexible electronics. Ferroelectric ceramics with high piezoelectric coefficient are inherently brittle, whereas polar polymers exhibit low piezoelectric coefficient. Here we report a highly stretchable/compressible piezoelectric composite composed of ferroelectric ceramic skeleton, elastomer matrix and relaxor ferroelectric-based hybrid at the ceramic/matrix interface as dielectric transition layers, exhibiting a giant piezoelectric coefficient of 250 picometers per volt, high electromechanical coupling factor keff of 65%, ultralow acoustic impedance of 3MRyl and high cyclic stability under 50% compression strain. The superior flexibility and piezoelectric properties are attributed to the electric polarization and mechanical load transfer paths formed by the ceramic skeleton, and the dielectric mismatch mitigation between ceramic fillers and elastomer matrix by the dielectric transition layer. The synergistic fusion of ultrahigh piezoelectric properties and superior flexibility in these polymer composites is expected to drive emerging applications in flexible smart electronics.

Current DNA base editors contain nuclease and DNA deaminase that enables deamination of cytosine (C) or adenine (A), but no method for guanine (G) or thymine (T) editing is available now. Here we developed a deaminase-free glycosylase-based guanine base editor (gGBE) with G editing ability, by fusing Cas9 nickase with engineered N-methylpurine DNA glycosylase protein (MPG). By several rounds of MPG mutagenesis via unbiased and rational screening using an intron-split EGFP reporter, we demonstrated that gGBE with engineered MPG could increase G editing efficiency by more than 1,500 folds. Furthermore, this gGBE exhibited high base editing efficiency (up to 81.2%) and high G-to-T or G-to-C (i.e., G-to-Y) conversion ratio (up to 0.95) in both cultured human cells and mouse embryos. Thus, we have provided a proof-of-concept of a new base-editing approach by endowing the engineered DNA glycosylase the capability to selectively excising a new type of substrate.

Stacking state of the atomic layers critically determines the physical properties of the twisted van der Waals materials. Unfortunately, precise characterization of the stacked interfaces remains a grant challenge as they are buried internally. By conductive atomic force microscopy, we show that the moiré superlattice structure formed at the embedded interfaces of small-angle twisted multilayer graphene (tMLG) can noticeably regulate the surface conductivity even when they are 10 atomic layers beneath the surface. Assisted by molecular dynamics (MD) simulations, a theoretical model is proposed to correlate the surface conductivity with the sequential stacking state of the graphene layers of tMLG. The theoretical model is then employed to extract the complex structure of a tMLG sample with crystalline defects. Our work offers a powerful tool for probing and visualizing the internal stacking structures of twisted layered materials through simple surface conductivity mapping, which are essential for understanding their unique physical properties.

It has long been established that plastic flow in the asthenosphere interacts constantly with the overlying lithosphere and plays a pivotal role in controlling the occurrence of geohazards such as earthquakes and volcanic eruptions. Unfortunately, accurately characterizing the direction and lateral extents of the mantle flow field is notoriously difficult, especially in oceanic areas where deployment of ocean bottom seismometers (OBSs) is expensive and thus rare. In this study, by applying shear wave splitting analyses to a dataset recorded by an OBS array that we deployed between mid-2019 and mid-2020 in the South China Sea (SCS), we show that the dominant mantle flow field has a NNW-SSE orientation, which can be attributed to mantle flow extruded from the Tibetan Plateau by the ongoing Indian-Eurasian collision. In addition, the results suggest that E-W oriented flow fields observed in South China and the Indochina Peninsula do not extend to the central SCS.

The North Atlantic Ocean hosts the largest volume of global subtropical mode waters (STMWs), serving as heat, carbon, and oxygen silos in the ocean interior. STMWs are formed in the Gulf Stream region where thermal fronts are pervasive with strong feedbacks to atmosphere. However, their roles in the STMW formation have been overlooked. Using eddy-resolving global climate simulations, we find that suppressing local frontal-scale ocean-to-atmosphere (FOA) feedback leads to STMW formation being reduced almost by half. This is because FOA feedback enlarges STMW outcropping, attributable to the mixed layer deepening associated with cumulative excessive latent heat loss due to higher wind speeds and greater air-sea humidity contrast driven by the Gulf Stream fronts. Such enhanced heat loss overshadows the stronger restratification induced by vertical eddy and turbulent heat transport, making STMW colder and heavier. With more realistic representation of FOA feedback, the eddy-present/rich coupled global climate models reproduce the observed STMWs much better than the eddy-free ones. Such improvement in STMW production cannot be achieved even with the oceanic resolution solely refined but without coupling to the overlying atmosphere in oceanic general circulation models. Our findings highlight the need to resolve FOA feedback to ameliorate the common severe underestimation of STMW and associated heat and carbon uptakes in earth system models.

In the solar system, oldhamite (CaS) is generally considered to be formed by the condensation of solar nebula gas. Enstatite chondrites, one of the most important repositories of oldhamite, are believed to be the representative of the material which formed Earth. Thus, the formation mechanism and the evolution process of oldhamite are of great significance to the deep understanding of the solar nebula, meteorites, the origin of Earth, and the C-O-S-Ca cycles of Earth. Until now, oldhamite has not been reported to occur in mantle rock. However, here we show the formation of oldhamite through the reaction between sulfide-bearing orthopyroxenite and molten CaCO3 at 1.5 GPa/1510 K, 0.5 GPa/1320 K, and 0.3 GPa/1273 K. Importantly, this reaction occurs at oxygen fugacities within the range of upper mantle conditions, 6 orders of magnitude higher than that of the solar nebula mechanism. Oldhamite is easily oxidized to CaSO4 or hydrolyzed to produce calcium hydroxide. Low oxygen fugacity of magma, extremely low oxygen content of the atmosphere, and the lack of a large amount of liquid water on the planet's surface are necessary for the widespread existence of oldhamite on the surface of a planet; otherwise, anhydrite or gypsum will exist in large quantities. Oldhamites may exist in the upper mantle beneath mid-ocean ridges. Additionally, oldhamites may have been a contributing factor to the early Earth's atmospheric hypoxia environment, and the transient existence of oldhamites during the interaction between reducing sulfur-bearing magma and carbonate could have had an impact on the changes in atmospheric composition during the Permian-Triassic Boundary.

Nonlinear responses of superconductors to intense terahertz radiation has been an active research frontier. Using terahertz pump-terahertz probe spectroscopy, we investigate the c-axis nonlinear optical response of a high-temperature superconducting cuprate. After excitation by a single-cycle terahertz pump pulse, the reflectivity of the probe pulse oscillates as the pump-probe delay is varied. Interestingly, the oscillatory central frequency scales linearly with the probe frequency, a fact widely overlooked in pump-probe experiments. By theoretically solving the nonlinear optical reflection problem on the interface, we show our observation is well explained by the Josephson-type third-order nonlinear electrodynamics, together with the emission coefficient from inside the material into free space. The latter results in a strong enhancement of emitted signal whose physical frequency is around the Josephson plasma edge. Our result offers a benchmark for and new insights into strong-field terahertz spectroscopy of related quantum materials.

The quantum anomalous Hall effect (QAHE) has unique advantages in topotronic applications, but it is still challenging to realize the QAHE with tunable magnetic and topological properties for building functional devices. Through systematic first-principles calculations, we predict that the in-plane magnetization induced QAHE with Chern numbers C = ±1 and the out-of-plane magnetization induced QAHE with high Chern numbers C = ±3 can be realized in a single material candidate, which is composed of van der Waals (vdW) coupled Bi and MnBi2Te4 monolayers. The switching between different phases of QAHE can be controllable by multiple ways, such as applying strain or (weak) magnetic field or twisting the vdW materials. The prediction of an experimentally available material system hosting robust, highly tunable QAHE will stimulate great research interest in the field. Our work opens a new avenue for the realization of tunable QAHE and provides a practical material platform for the development of topological electronics.

Oxygen reduction reactions (ORR) involve a multistep proton-coupled electron process accompanied by the conversion of the apodictic spin configuration. Understanding the role of spin configurations of metals in the adsorption and desorption of oxygen intermediates during ORR is critical for the design of efficient ORR catalysts. Herein, a platinum–rare earth metal-based alloy catalyst, Pt2Gd, is introduced to reveal the role of spin configurations in the catalytic activity of materials. The catalyst exhibits a unique intrinsic spin reconfiguration because of interactions between the Gd-4f and Pt-5d orbitals. The adsorption and desorption of the oxygen species are optimized by modifying the spin symmetry and electronic structures of the material for increased ORR efficiency. The Pt2Gd alloy exhibits a half-wave potential of 0.95 V and a superior mass activity of 1.5 A·mgPt−1 in a 0.1 M HClO4 electrolyte, as well as higher durability than conventional Pt/C catalysts. Theoretical calculations have proved that the spin shielding effect of the Gd pairs increases the spin symmetry of the Pt-5d orbitals and the adsorption preferences toward spin-polarized intermediates to facilitate ORR. This work clarifies the effect of modulating the local high-spin 4f orbital electrons in rare earth metals on the intrinsic spin state of Pt to enhance its ORR performance, thus fundamentally contributing to the understanding of new descriptors that control the ORR activity.

Contrary to the current consensus, I argue that the existing evidence for high temperature superconductivity in hydrides under high pressure is not compelling. I suggest that the focus of the field should urgently shift to establish unequivocally experimentally whether or not superconductivity in pressurized hydrides exists, instead of continuing to search for new materials that might show elusive signals of unproven superconductivity at ever higher temperatures. The implications of a negative finding for the theoretical understanding of superconductivity are discussed.

Gas diffusion electrodes (GDEs) mediate the transport of reactants, products, and electrons for electrocatalytic CO2 reduction reaction (CO2RR) in membrane electrode assemblies (MEAs). Random distribution of ionomers, added by the traditional physical mixing method, in the catalyst layer of GDEs affects the transport of ions and CO2. Such a phenomenon results in elevated cell voltage and decaying selectivity at high current densities. This paper describes a pre-confinement method to construct GDEs with homogeneously distributed ionomer, which enhances the mass transfer locally at the active centers. The optimized GDEs exhibited comparatively low cell voltages and high CO Faradaic efficiencies (FE > 90%) at a wide range of current densities. It can also operate stably for over 220 h with the cell voltage staying almost unchanged. This good performance can be preserved even with diluted CO2 feeds, which is essential for pursuing a high single-pass conversion rate. This study provides a new approach to building efficient mass transfer pathways for ions and reactants in GDEs to promote the electrocatalytic CO2RR for practical applications.

An intelligent indoor metasurface robotic is empowered on the physical layer by programmable metasurfaces and on the cyber layer by artificial-intelligence tools.