Efficient electrochemical reduction of CO2 to CO in a flow cell device by a pristine Cu5tz6-cluster-based metal-organic framework.

The electrochemical reduction of CO2 to CO is a powerful approach to achieving carbon neutrality. Herein, we report a five-nuclear copper cluster-based metal-azolate framework CuTz-1 as an electrocatalyst for the electrochemical CO2 reduction reaction. It achieved a faradaic efficiency (FE) of 62.7% for yielding CO with a partial current density of -35.1 mA cm-2 in flow cell device, which can be preserved for more than ten hours with negligible changes of the current density and FE(CO). Studies of electrocatalytic mechanism studies revealed that the distance of Cu-N was increased, and the coordination number of the Cu ion was reduced, while the oxidation state of Cu was decreased after the electrocatalysis. These findings offer valuable insights into structural changes that influence the performance of the catalyst during the process of the electrochemical reduction of CO2 process.

Enhanced polarization switching characteristics of HfO2 ultrathin films via acceptor-donor co-doping.

In the realm of ferroelectric memories, HfO2-based ferroelectrics stand out because of their exceptional CMOS compatibility and scalability. Nevertheless, their switchable polarization and switching speed are not on par with those of perovskite ferroelectrics. It is widely acknowledged that defects play a crucial role in stabilizing the metastable polar phase of HfO2. Simultaneously, defects also pin the domain walls and impede the switching process, ultimately rendering the sluggish switching of HfO2. Herein, we present an effective strategy involving acceptor-donor co-doping to effectively tackle this dilemma. Remarkably enhanced ferroelectricity and the fastest switching process ever reported among HfO2 polar devices are observed in La3+-Ta5+ co-doped HfO2 ultrathin films. Moreover, robust macro-electrical characteristics of co-doped films persist even at a thickness as low as 3 nm, expanding potential applications of HfO2 in ultrathin devices. Our systematic investigations further demonstrate that synergistic effects of uniform microstructure and smaller switching barrier introduced by co-doping ensure the enhanced ferroelectricity and shortened switching time. The co-doping strategy offers an effective avenue to control the defect state and improve the ferroelectric properties of HfO2 films.

Electric field control of perpendicular magnetic tunnel junctions with easy-cone magnetic anisotropic free layers.

Magnetic tunnel junctions (MTJs) are the core element of spintronic devices. Currently, the mainstream writing operation of MTJs is based on electric current with high energy dissipation, and it can be notably reduced if an electric field is used instead. In this regard, it is promising for electric field control of MTJ in the multiferroic heterostructure composed of MTJ and ferroelectrics via strain-mediated magnetoelectric coupling. However, there are only reports on MTJs with in-plane anisotropy so far. Here, we investigate electric field control of the resistance state of MgO-based perpendicular MTJs with easy-cone anisotropic free layers through strain-mediated magnetoelectric coupling in multiferroic heterostructures. A remarkable, nonvolatile, and reversible modulation of resistance at room temperature is demonstrated. Through local reciprocal space mapping under different electric fields for Pb(Mg1/3Nb2/3)0.7Ti0.3O3 beneath the MTJ pillar, the modulation mechanism is deduced. Our work represents a crucial step toward electric field control of spintronic devices with non-in-plane magnetic anisotropy.

Optineurin-facilitated axonal mitochondria delivery promotes neuroprotection and axon regeneration.

Optineurin (OPTN) mutations are linked to amyotrophic lateral sclerosis (ALS) and normal tension glaucoma (NTG), but a relevant animal model is lacking, and the molecular mechanisms underlying neurodegeneration are unknown. We found that OPTN C-terminus truncation (OPTN∆C) causes late-onset neurodegeneration of retinal ganglion cells (RGCs), optic nerve (ON), and spinal cord motor neurons, preceded by a striking decrease of axonal mitochondria. Surprisingly, we discover that OPTN directly interacts with both microtubules and the mitochondrial transport complex TRAK1/KIF5B, stabilizing them for proper anterograde axonal mitochondrial transport, in a C-terminus dependent manner. Encouragingly, overexpressing OPTN/TRAK1/KIF5B reverses not only OPTN truncation-induced, but also ocular hypertension-induced neurodegeneration, and promotes striking ON regeneration. Therefore, in addition to generating new animal models for NTG and ALS, our results establish OPTN as a novel facilitator of the microtubule-dependent mitochondrial transport necessary for adequate axonal mitochondria delivery, and its loss as the likely molecular mechanism of neurodegeneration.

Bifunctional Square-Planar NiO4 Coordination of Topotactic LaNiO2.0 Films for Efficient Oxygen Evolution Reaction.

The high-efficient and low-cost oxygen evolution reaction (OER) is decisive for applications of oxide catalysts in metal-air batteries, electrolytic cells, and energy-storage technologies. Delicate regulations of active surface and catalytic reaction pathway of oxide materials principally determine thermodynamic energy barrier and kinetic rate during catalytic reactions, and thus have crucial impacts on OER performance. Herein, a synergistic modulation of catalytically active surface and reaction pathway through facile topotactic transformations switching from perovskite (PV) LaNiO3.0 film to infinite-layer (IL) LaNiO2.0 film is demonstrated, which absolutely contributes to improving OER performance. The square-planar NiO4 coordination of IL-LaNiO2.0 brings about more electrochemically active metal (Ni+ ) sites on the film surface. Meanwhile, the oxygen-deficient driven PV- IL topotactic transformations lead to a reaction pathway converted from absorbate evolution mechanism to lattice-oxygen-mediated mechanism (LOM). The non-concerted proton-electron transfer of LOM pathway, evidenced by the pH-dependent OER kinetics, further boosts the OER activity of IL-LaNiO2.0 films. These findings will advance the in-depth understanding of catalytic mechanisms and open new possibilities for developing highly active perovskite-derived oxide catalysts.

Enhanced Exchange Bias in Epitaxial High-Entropy Oxide Heterostructures.

High-entropy oxides (HEOs) have gained significant interest in recent years due to their unique structural characteristics and potential to tailor functional properties. However, the electronic structure of the HEOs currently remains vastly unknown. In this work, combining magnetometry measurements, scanning transmission electron microscopy, and element-specific X-ray absorption spectroscopy, the electronic structure and magnetic properties of the perovskite-HEO La(Cr0.2Mn0.2Fe0.2Co0.2Ni0.2)O3 epitaxial thin films are systemically studied. It is found that enhanced magnetic frustration emerges from competing exchange interactions of the five transition-metal cations with energetically favorable half-filled/full-filled electron configurations, resulting in an unprecedented large vertical exchange bias effect in the single-crystalline films. Furthermore, our findings demonstrate that the La(Cr0.2Mn0.2Fe0.2Co0.2Ni0.2)O3 layer with a thickness down to 1 nm can be used as a pinning layer and strongly coupled with a ferromagnetic La0.7Sr0.3MnO3 layer, leading to a notable exchange bias and coercivity enhancement in a cooling field as small as 5 Oe. Our studies not only provide invaluable insight into the electronic structure of HEOs but also pave the way for a new era of large bias materials for spintronics devices.

RGC-specific ATF4 and/or CHOP deletion rescues glaucomatous neurodegeneration and visual function.

Endoplasmic reticulum (ER) stress has been linked with various acute and chronic neurodegenerative diseases. We previously found that optic nerve (ON) injury and diseases induce neuronal ER stress in retinal ganglion cells (RGCs). We further demonstrated that germline deletion of CHOP preserves the structure and function of both RGC somata and axons in mouse glaucoma models. Here we report that RGC-specific deletion of CHOP and/or its upstream regulator ATF4 synergistically promotes RGC and ON survival and preserves visual function in mouse ON crush and silicone oil-induced ocular hypertension (SOHU) glaucoma models. Consistently, topical application of the ATF4/CHOP chemical inhibitor ISRIB or RGC-specific CRISPR-mediated knockdown of the ATF4 downstream effector Gadd45a also delivers significant neuroprotection in the SOHU glaucoma model. These studies suggest that blocking the neuronal intrinsic ATF4/CHOP axis of ER stress is a promising neuroprotection strategy for neurodegeneration.

Spin State Disproportionation in Insulating Ferromagnetic LaCoO3 Epitaxial Thin Films.

The origin of insulating ferromagnetism in epitaxial LaCoO3 films under tensile strain remains elusive despite extensive research efforts are devoted. Surprisingly, the spin state of its Co ions, the main parameter of its ferromagnetism, is still to be determined. Here, the spin state in epitaxial LaCoO3 thin films is systematically investigated to clarify the mechanism of strain-induced ferromagnetism using element-specific X-ray absorption spectroscopy and dichroism. Combining with the configuration interaction cluster calculations, it is unambiguously demonstrated that Co3+ in LaCoO3 films under compressive strain (on LaAlO3 substrate) is practically a low-spin state, whereas Co3+ in LaCoO3 films under tensile strain (on SrTiO3 substrate) have mixed high-spin and low-spin states with a ratio close to 1:3. From the identification of this spin state ratio, it is inferred that the dark strips observed by high-resolution scanning transmission electron microscopy indicate the position of Co3+ high-spin state, i.e., an observation of a spin state disproportionation in tensile-strained LaCoO3 films. This consequently explains the nature of ferromagnetism in LaCoO3 films. The study highlights the importance of spin state degrees of freedom, along with thin-film strain engineering, in creating new physical properties that do not exist in bulk materials.

Magnetotransport property of oxygen-annealed Fe1+yTe thin films.

Fe-based superconductors are one of the current research focuses. FeTe is unique in the series of FeSe1-xTex, since it is nonsuperconducting near the FeTe side in the phase diagram in contrast to the presence of superconductivity in other region. However, FeTe thin films become superconducting after oxygen annealing and the mechanism remains elusive. Here, we report the temperature dependences of resistivity, Hall effect and magnetoresistance (MR) of a series of FeTe thin films with different amounts of excess Fe and oxygen. These properties show dramatic changes with excess Fe and oxygen incorporation. We found the Hall coefficients are positive for the oxygen-annealed samples, in contrast to the transition from positive to negative below 50 K for the vacuum-annealed samples. For all samples, both the resistivity and Hall coefficient show a dramatic drop, respectively, at around 50 K-75 K, implying coexistence of superconductivity and antiferromagnetic order for the oxygen-annealed samples. The vacuum-annealed samples show both positive and negative values of MR depending on temperature, while negative MR dominates for the oxygen-annealed samples. We also found that oxygen annealing reduces the excess Fe in FeTe, which has been neglected before. The results are discussed in terms of several contributions, and a comparison is made between the oxygen-annealed FeTe thin films and FeSe1-xTex. This work is helpful for shedding light on the understanding of oxygen-annealed FeTe thin films.

Unusual double ligand holes as catalytic active sites in LiNiO2.

Designing efficient catalyst for the oxygen evolution reaction (OER) is of importance for energy conversion devices. The anionic redox allows formation of O-O bonds and offers higher OER activity than the conventional metal sites. Here, we successfully prepare LiNiO2 with a dominant 3d8L configuration (L is a hole at O 2p) under high oxygen pressure, and achieve a double ligand holes 3d8L2 under OER since one electron removal occurs at O 2p orbitals for NiIII oxides. LiNiO2 exhibits super-efficient OER activity among LiMO2, RMO3 (M = transition metal, R = rare earth) and other unary 3d catalysts. Multiple in situ/operando spectroscopies reveal NiIII→NiIV transition together with Li-removal during OER. Our theory indicates that NiIV (3d8L2) leads to direct O-O coupling between lattice oxygen and *O intermediates accelerating the OER activity. These findings highlight a new way to design the lattice oxygen redox with enough ligand holes created in OER process.

Differential effects of SARM1 inhibition in traumatic glaucoma and EAE optic neuropathies.

Optic neuropathy is a group of optic nerve (ON) diseases with progressive degeneration of ON and retinal ganglion cells (RGCs). The lack of neuroprotective treatments is a central challenge for this leading cause of irreversible blindness. SARM1 (sterile α and TIR motif-containing protein 1) has intrinsic nicotinamide adenine dinucleotide (NAD+) hydrolase activity that causes axon degeneration by degrading axonal NAD+ significantly after activation by axon injury. SARM1 deletion is neuroprotective in many, but not all, neurodegenerative disease models. Here, we compare two therapy strategies for SARM1 inhibition, antisense oligonucleotide (ASO) and CRISPR, with germline SARM1 deletion in the neuroprotection of three optic neuropathy mouse models. This study reveals that, similar to germline SARM1 knockout in every cell, local retinal SARM1 ASO delivery and adeno-associated virus (AAV)-mediated RGC-specific CRISPR knockdown of SARM1 provide comparable neuroprotection to both RGC somata and axons in the silicone oil-induced ocular hypertension (SOHU) glaucoma model but only protect RGC axons, not somata, after traumatic ON injury. Surprisingly, neither of these two therapy strategies of SARM1 inhibition nor SARM1 germline knockout (KO) benefits RGC or ON survival in the experimental autoimmune encephalomyelitis (EAE)/optic neuritis model. Our studies therefore suggest that SARM1 inhibition by local ASO delivery or AAV-mediated CRISPR is a promising neuroprotective gene therapy strategy for traumatic and glaucomatous optic neuropathies but not for demyelinating optic neuritis.

Highly Oxidized Oxide Surface toward Optimum Oxygen Evolution Reaction by Termination Engineering.

The oxygen evolution reaction (OER) is a critical step for sustainable fuel production through electrochemistry process. Maximizing active sites of nanocatalyst with enhanced intrinsic activity, especially the activation of lattice oxygen, is gradually recognized as the primary incentive. Since the surface reconfiguration to oxyhydroxide is unavoidable for oxygen-activated transition metal oxides, developing a surface termination like oxyhydroxide in oxides is highly desirable. In this work, we demonstrate an unusual surface termination of (111)-facet Co3O4 nanosheet that is exclusively containing edge-sharing octahedral Co3+ similar to CoOOH that can perform at approximately 40 times higher current density at 1.63 V (vs RHE) than commercial RuO2. It is found that this surface termination has an oxidized oxygen state in contrast to standard Co-O systems, which can serve as active site independently, breaking the scaling relationship limit. This work forwards the applications of oxide electrocatalysts in the energy conversion field by surface termination engineering.

Composition Design and Fundamental Properties of Ultra-High-Performance Concrete Based on a Modified Fuller Distribution Model.

Both the discrete and continuous particle packing models are used to design UHPC, but the influences of a water film covering the particle surfaces on the compactness of the particle system were not considered in these models. In fact, the water film results in a certain distance between solid particles (DSP), which affects the compactness of the particle system, especially for cementitious materials with small particle sizes. In the present study, the mixture design method for UHPC was proposed based on the Fuller distribution model modified using the DSP. Then, the components of cementitious materials and aggregates were optimized, and the UHPC matrices with high solid concentrations were obtained. The results showed that the solid concentration, slump flow, and compressive strength of the UHPC matrix reached 77.1 vol.%, 810 mm, and 162.0 MPa, respectively. By replacing granulated blast furnace slag (GBFS) with quartz powder (QP), the flexural strength of the UHPC matrix was increased without reducing its compressive strength. When the steel fiber with a volume fraction of 1.5% was used, the slump flow, compressive strength, tensile strength, and flexural strength of the UHPC reached 740 mm, 175.6 MPa, 9.7 MPa, and 22.8 MPa, respectively. After 500 freeze-thaw cycles or 60 dry-wet cycles under sulfate erosion, the mechanical properties did not deteriorate. The chloride diffusion coefficients in UHPCs were lower than 3.0 × 10-14 m2/s, and the carbonation depth of each UHPC was 0 mm after carbonization for 28 days. The UHPCs presented ideal workability, mechanical properties, and durability, demonstrating the validity of the method proposed for UHPC design.

Promoting Electrocatalytic CO2 Reduction to CH4 by Copper Porphyrin with Donor-Acceptor Structures.

Molecular catalysts have been receiving increasingly attention in the electrochemical CO2 reduction reaction (CO2 RR) with attractive features such as precise catalytic sites and tunable ligands. However, the insufficient activity and low selectivity of deep reduction products restrain the utilization of molecular catalysts in CO2 RR. Herein, a donor-acceptor modified Cu porphyrin (CuTAPP) is developed, in which amino groups are linked to donate electrons toward the central CuN4 site to enhance the CO2 RR activity. The CuTAPP catalyst exhibited an excellent CO2 -to-CH4 electroreduction performance, including a high CH4 partial current density of 290.5 mA cm-2 and a corresponding Faradaic efficiency of 54.8% at -1.63 V versus reversible hydrogen electrode in flow cells. Density functional theory calculations indicated that CuTAPP presented a much lower energy gap in the pathway of producing *CHO than Cu porphyrin without amino group modification. This work suggests a useful strategy of introducing designed donor-acceptor structures into molecular catalysts for enhancing electrochemical CO2 conversion toward deep reduction products.

Silicone Oil-Induced Glaucomatous Neurodegeneration in Rhesus Macaques.

Previously, we developed a simple procedure of intracameral injection of silicone oil (SO) into mouse eyes and established the mouse SOHU (SO-induced ocular hypertension under-detected) glaucoma model with reversible intraocular pressure (IOP) elevation and significant glaucomatous neurodegeneration. Because the anatomy of the non-human primate (NHP) visual system closely resembles that of humans, it is the most likely to predict human responses to diseases and therapies. Here we tried to replicate the mouse SOHU glaucoma model in rhesus macaque monkeys. All six animals that we tested showed significant retinal ganglion cell (RGC) death, optic nerve (ON) degeneration, and visual functional deficits at both 3 and 6 months. In contrast to the mouse SOHU model, however, IOP changed dynamically in these animals, probably due to individual differences in ciliary body tolerance capability. Further optimization of this model is needed to achieve consistent IOP elevation without permanent damage of the ciliary body. The current form of the NHP SOHU model recapitulates the severe degeneration of acute human glaucoma, and is therefore suitable for assessing experimental therapies for neuroprotection and regeneration, and therefore for translating relevant findings into novel and effective treatments for patients with glaucoma and other neurodegenerations.

Effects of Typical Solvents on the Structural Integrity and Properties of Activated Kaolinite by Wet Ball Milling.

The influence of organic solvents on the structural integrity and properties of activated kaolinite were compared and analyzed via characterization techniques and molecular dynamics (MD) simulation. The results revealed that the organic intercalators can be easily inserted into the interlayer spaces of activated kaolinite within a short time of the wet ball milling. The DMSO intercalated kaolinites maintained structural integrity due to the high intercalation rate and the excellent buffering effect against the crushing force of milling during the delamination/exfoliation process. The delaminated layers of the DMSO-kaolinite complex exhibited a high specific surface area of 99.12 m2/g and a low average thickness of 35.21 nm. The calculated elastic properties of the organo-kaolinite complex manifested the intercalation of DMSO into a kaolinite interlayer, which could improve the compressibility and structural integrity of kaolinite nanosheets. The DMSO-kaolinite complex was easier to peel off when compared to the other organic intercalators due to its more intercalated molecules.

Longitudinal in vivo Ca2+ imaging reveals dynamic activity changes of diseased retinal ganglion cells at the single-cell level.

Retinal ganglion cells (RGCs) are heterogeneous projection neurons that convey distinct visual features from the retina to brain. Here, we present a high-throughput in vivo RGC activity assay in response to light stimulation using noninvasive Ca2+ imaging of thousands of RGCs simultaneously in living mice. Population and single-cell analyses of longitudinal RGC Ca2+ imaging reveal distinct functional responses of RGCs and unprecedented individual RGC activity conversions during traumatic and glaucomatous degeneration. This study establishes a foundation for future in vivo RGC function classifications and longitudinal activity evaluations using more advanced imaging techniques and visual stimuli under normal, disease, and neural repair conditions. These analyses can be performed at both the population and single-cell levels using temporal and spatial information, which will be invaluable for understanding RGC pathophysiology and identifying functional biomarkers for diverse optic neuropathies.

Phase Competition in High-Quality Epitaxial Antiferroelectric PbZrO3 Thin Films.

Antiferroelectric PbZrO3 has attracted renewed interest in recent years because of its unique properties and wide range of potential applications. However, the nature of antiferroelectricity and its evolution with the electric field and temperature remain controversial, mostly due to the difficulty of obtaining high-quality single-crystal samples. The lack of consensus regarding the phase transition in PbZrO3 is not only important on a fundamental side but also greatly hinders further applications. Herein, high-quality PbZrO3 epitaxial thin films are successfully fabricated by pulsed laser deposition. The structural and physical properties of the films are systematically studied via a combination of electric property measurements, X-ray diffraction, scanning transmission electron microscopy imaging, and second-harmonic generation studies. Our studies unveil the noncentrosymmetric nature of PbZrO3 films at room temperature. Moreover, the Curie temperature increased to 270°, ∼40° higher than that in the bulk, and no intermediate ferroelectric phase was observed. Besides, an incipient ferroelectric with relaxor-like behavior above the Curie temperature due to the existence of a local polar cluster in the high-temperature paraelectric phase is experimentally observed for the first time. Our studies provide a better understanding of PbZrO3 thin films and pave the way for practical applications of antiferroelectric material in modern electronic devices.

Maprotiline restores ER homeostasis and rescues neurodegeneration via Histamine Receptor H1 inhibition in retinal ganglion cells.

When the protein or calcium homeostasis of the endoplasmic reticulum (ER) is adversely altered, cells experience ER stress that leads to various diseases including neurodegeneration. Genetic deletion of an ER stress downstream effector, CHOP, significantly protects neuron somata and axons. Here we report that three tricyclic compounds identified through a small-scale high throughput screening using a CHOP promoter-driven luciferase cell-based assay, effectively inhibit ER stress by antagonizing their common target, histamine receptor H1 (HRH1). We further demonstrated that systemic administration of one of these compounds, maprotiline, or CRISPR-mediated retinal ganglion cell (RGC)-specific HRH1 inhibition, delivers considerable neuroprotection of both RGC somata and axons and preservation of visual function in two mouse optic neuropathy models. Finally, we determine that maprotiline restores ER homeostasis by inhibiting HRH1-mediated Ca2+ release from ER. In this work we establish maprotiline as a candidate neuroprotectant and HRH1 as a potential therapeutic target for glaucoma.

Inhibition Effect of Hydrophobic Functional Organic Corrosion Inhibitor in Reinforced Concrete.

Using an admixed organic corrosion inhibitor is one of the most efficient strategies to enhance the corrosion resistance and durability of reinforced concrete. However, traditional admixed organic corrosion inhibitors only increase the corrosion resistance of the embedded reinforcing steel, and the optimization effect on the pore structure and the impermeability of concrete is very limited. In this study, in order to evaluate the corrosion-inhibition effect of a novel hydrophobic functional organic corrosion inhibitor, the adsorption behavior of a hydrophobic functional organic corrosion inhibitor and its related effect on the electrochemical behavior of the reinforcing steel was investigated. In addition, this paper further discusses the effect of a hydrophobic functional organic corrosion inhibitor on pore structure and hydrophobic properties, as well as the impermeability of concrete. The results indicated that the hydrophobic functional organic corrosion inhibitor was effectively adsorbed on the surface of the steel bar, and the higher adsorption content was relevant to the higher inhibitor dosage. On one hand, the hydrophobic functional organic corrosion inhibitor exhibited both a pore-blocking effect and a hydrophobic effect on concrete, leading to a refined pore structure and reduced capillary water absorption amount; on the other hand, the hydrophobic functional organic corrosion inhibitor exhibited an excellent corrosion-inhibition effect on the reinforcement embedded in the concrete, presenting an inhibition efficiency higher than 90% with a concentration of 4 wt.%.