A prognostic and immunotherapeutic predictive model based on the cell-originated characterization of tumor microenvironment in lung adenocarcinoma.

Tumor microenvironment (TME) plays a crucial role in predicting prognosis and response to therapy in lung cancer. Our study established a prognostic and immunotherapeutic predictive model, the tumor immune cell score (TICS), by differentiating cell origins in lung adenocarcinoma (LUAD) based on the transcriptomic data of 2,510 patients in 14 independent cohorts, including 12 public datasets and two in-house cohorts. The high TICS was associated with prolonged overall survival (OS), especially in the early-stage LUAD. For the advanced-stage LUAD, high TICS predicted a superior OS in patients who were treated with immunotherapy instead of chemotherapy or TKI. The result suggested that TICS could serve as an indicator for the prognostic stratification management of patients in the early-stage LUAD, and as a potential guide for therapeutic decision-marking in the advanced-stage LUAD. Our findings provided an insight into prognosis stratification and potential guidance for treatment strategy selection.

Determining the absolute temporal field of ultra-broadband terahertz-infrared pulses with field-induced second-harmonic spectrograms.

We demonstrate the use of spectrograms of the field-induced second-harmonic (FISH) signal generated in ambient air, to reconstruct the absolute temporal electric field of ultra-broadband terahertz-infrared (THz-IR) pulses with bandwidths exceeding 100 THz. The approach is applicable even with relatively long (150-femtosecond) optical detection pulses, where the relative intensity and phase can be extracted from the moments of the spectrogram, as demonstrated by transmission spectroscopy of very thin samples. Auxiliary EFISH/ABCD measurements are used to provide the absolute field and phase calibration, respectively. We take into account the beam-shape/propagation effects about the detection focus on the measured FISH signals, which affect the field calibration, and show how an analysis of a set of measurements vs. truncation of the unfocused THz-IR beam can be used to correct for these. This approach could also be applied to the field calibration of ABCD measurements of conventional THz pulses.

Polarization Switching and Correlated Phase Transitions in Fluorite-Structure ZrO2 Nanocrystals.

Unconventional ferroelectricity in fluorite-structure oxides enables tremendous opportunities in nanoelectronics owing to their superior scalability and silicon compatibility. However, their polarization order and switching process remain elusive due to the challenges of visualizing oxygen ions in nanocrystalline films. Here, we directly capture the oxygen shifting during polarization switching and correlated polar-nonpolar phase transitions among multiple metastable phases in freestanding ZrO2 thin films by low-dose integrated differential phase-contrast scanning transmission electron microscopy (iDPC-STEM). Bidirectional transitions between antiferroelectric and ferroelectric orders and interfacial polarization relaxation are clarified at unit-cell scale. Meanwhile, polarization switching is strongly correlated with Zr-O displacement in reversible martensitic transformation between monoclinic and orthorhombic phases and two-step tetrahedral-to-orthorhombic phase transition. These findings provide atomic insights into the transition pathways between metastable polymorphs and unravel the evolution of polarization orders in (anti)ferroelectric fluorite oxides. This article is protected by copyright. All rights reserved.

Unveiling Strong Ion-Electron-Lattice Coupling and Electronic Antidoping in Hydrogenated Perovskite Nickelate.

Despite being highly promising for applications in emergent electronic devices, decoding both the ion-electron-lattice coupling in correlated materials at the atomic scale and the electronic band structure remains a big challenge due to the strong and complex correlation among these degrees of freedom. Here, taking an epitaxial thin film of perovskite nickelate NdNiO3 as a model system, hydrogen-ion-induced giant lattice distortion and enhanced NiO6 octahedra tilting/rotation are demonstrated, which leads to a new robust hydrogenated HNdNiO3 phase with lattice expansion larger than 10% on a series of substrates. Moreover, under the effect of ion-electron synergistic doping, it is found that the proposed electronic antidoping, i.e., the doped electrons mainly fill the ground-state oxygen 2p holes instead of changing the Ni oxidation state from Ni3+ to Ni2+ , dominates the metal-insulator transition. Meanwhile, lattice modification with enhanced Ni-O-Ni bond tilting or rotation mainly modifies the orbital density of states near the Fermi level. Last, by electric-field-controlled hydrogen-ion intercalation and its strong coupling to the lattice and electron charge, selective micrometer-scale patterns with distinct structural and electronic states are fabricated. The results provide direct evidence for a strong ion-electron-lattice coupling in correlated physics and exhibit its potential applications in designing novel materials and devices.

Surface Lattice Modulation through Chemical Delithiation toward a Stable Nickel-Rich Layered Oxide Cathode.

Nickel-rich layered oxides (NLOs) are considered as one of the most promising cathode materials for next-generation high-energy lithium-ion batteries (LIBs), yet their practical applications are currently challenged by the unsatisfactory cyclability and reliability owing to their inherent interfacial and structural instability. Herein, we demonstrate an approach to reverse the unstable nature of NLOs through surface solid reaction, by which the reconstructed surface lattice turns stable and robust against both side reactions and chemophysical breakdown, resulting in improved cycling performance. Specifically, conformal La(OH)3 nanoshells are built with their thicknesses controlled at nanometer accuracy, which act as a Li+ capturer and induce controlled reaction with the NLO surface lattices, thereby transforming the particle crust into an epitaxial layer with localized Ni/Li disordering, where lithium deficiency and nickel stabilization are both achieved by transforming oxidative Ni3+ into stable Ni2+. An optimized balance between surface stabilization and charge transfer is demonstrated by a representative NLO material, namely, LiNi0.83Co0.07Mn0.1O2, whose surface engineering leads to a highly improved capacity retention and excellent rate capability with a strong capability to inhibit the crack of NLO particles. Our study highlights the importance of surface chemistry in determining chemical and structural behaviors and paves a research avenue in controlling the surface lattice for the stabilization of NLOs toward reliable high-energy LIBs.

Coupling Probiotics with 2D CoCuMo-LDH Nanosheets as a Tumor-Microenvironment-Responsive Platform for Precise NIR-II Photodynamic Therapy.

Photodynamic therapy (PDT) has become a promising cancer treatment approach with superior advantages. However, it remains a grand challenge to develop tumor microenvironment (TME)-responsive photosensitizers (PSs) for tumor-targeting precise PDT. Herein, the coupling Lactobacillus acidophilus (LA) probiotics with 2D CoCuMo layered-double-hydroxide (LDH) nanosheets (LA&LDH) is reported as a TME-responsive platform for precise NIR-II PDT. The CoCuMo-LDH nanosheets loaded on LA can be transformed from crystalline into amorphous through etching by the LA-metabolite-enabled low pH and overexpressed glutathione. The TME-induced in situ amorphization of CoCuMo-LDH nanosheets can boost its photodynamic activity for singlet oxygen (1 O2 ) generation under 1270 nm laser irradiation with relative 1 O2 quantum yield of 1.06, which is the highest among previously reported NIR-excited PSs. In vitro and in vivo assays prove that the LA&LDH can effectively achieve complete cell apoptosis and tumor eradication under 1270 nm laser irradiation. This study proves that the probiotics can be used as a tumor-targeting platform for highly efficient precise NIR-II PDT.

Dual-bionic regenerative microenvironment for peripheral nerve repair.

Autologous nerve grafting serves is considered the gold standard treatment for peripheral nerve defects; however, limited availability and donor area destruction restrict its widespread clinical application. Although the performance of allogeneic decellularized nerve implants has been explored, challenges such as insufficient human donors have been a major drawback to its clinical use. Tissue-engineered neural regeneration materials have been developed over the years, and researchers have explored strategies to mimic the peripheral neural microenvironment during the design of nerve catheter grafts, namely the extracellular matrix (ECM), which includes mechanical, physical, and biochemical signals that support nerve regeneration. In this study, polycaprolactone/silk fibroin (PCL/SF)-aligned electrospun material was modified with ECM derived from human umbilical cord mesenchymal stem cells (hUMSCs), and a dual-bionic nerve regeneration material was successfully fabricated. The results indicated that the developed biomimetic material had excellent biological properties, providing sufficient anchorage for Schwann cells and subsequent axon regeneration and angiogenesis processes. Moreover, the dual-bionic material exerted a similar effect to that of autologous nerve transplantation in bridging peripheral nerve defects in rats. In conclusion, this study provides a new concept for designing neural regeneration materials, and the prepared dual-bionic repair materials have excellent auxiliary regenerative ability and further preclinical testing is warranted to evaluate its clinical application potential.

Boosting the Sonodynamic Cancer Therapy Performance of 2D Layered Double Hydroxide Nanosheet-Based Sonosensitizers Via Crystalline-to-Amorphous Phase Transformation.

Sonodynamic therapy (SDT) has been a promising therapeutic modality for cancer because of its superior advantages compared with other therapeutic strategies. However, the current sonosensitizers used for SDT normally exhibit low activity for ultrasound (US)-induced reactive oxygen species (ROS) generation. Herein, the crystalline-to-amorphous phase transformation is reported as a simple but powerful strategy to engineer ultrathin 2D CoW-LDH and NiW-LDH nanosheets as highly efficient sonosensitizers for SDT. The phase transformation of CoW-LDH and NiW-LDH nanosheets from polycrystalline to amorphous ones is achieved through a simple acid etching treatment. Importantly, compared with the polycrystalline one, the amorphous CoW-LDH (a-CoW-LDH) nanosheets possess higher ROS generation activity under US irradiation, which is ≈17 times of the commercial TiO2 sonosensitizer. The results suggest that the enhanced performance of ultrathin a-CoW-LDH nanosheets for US-induced ROS generation may be attributed to the phase transformation-induced defect generation and electronic structure changes. After polyethylene glycol modification, the a-CoW-LDH nanosheets can serve as a high-efficiency sonosensitizer for SDT to achieve cell death in vitro and tumor eradication in vivo under US irradiation.

Preparation of 2D Polyaniline/MoO3- x Superlattice Nanosheets via Intercalation-Induced Morphological Transformation for Efficient Chemodynamic Therapy.

Organic intercalation of layered nanomaterials is an attractive strategy to fabricate organic/inorganic superlattices for a wide range of promising applications. However, the synthesis of 2D organic/inorganic superlattice nanosheets remains a big challenge. Herein, the preparation of 2D polyaniline/MoO3- x (PANI/MoO3- x ) superlattice nanosheets via intercalation-induced morphological transformation from MoO3  nanobelts, as efficient Fenton-like reagents for chemodynamic therapy (CDT), is reported. Micrometer-long MoO3  nanobelts are co-intercalated with Na+ /H2 O followed by the guest exchange with aniline monomer for in situ polymerization to obtain PANI/MoO3- x nanosheets. Intriguingly, the PANI intercalation can induce the morphological transformation from long MoO3  nanobelts to 2D PANI/MoO3- x nanosheets along with the partial reduction of Mo6+ to Mo5+ , and generation of rich oxygen vacancies. More importantly, thanks to the PANI intercalation-induced activation, the PANI/MoO3- x nanosheets exhibit excellent Fenton-like catalytic activity for generation of hydroxyl radical (·OH) by decomposing H2 O2  compared with the MoO3  nanobelts. It is speculated that the good conductivity of PANI can facilitate electron transport during the Fenton-like reaction, thereby enhancing the efficiency of CDT. Thus, the polyvinylpyrrolidone-modified PANI/MoO3- x nanosheets can function as Fenton-like reagents for highly efficient CDT to kill cancer cells and eradicate tumors.

Self-Intercalated 1T-FeSe2 as an Effective Kagome Lattice.

In kagome lattice, with the emergence of Dirac cones and flat band in electronic structure, it provides a versatile ground for exploring intriguing interplay among frustrated geometry, topology and correlation. However, such engaging interest is strongly limited by available kagome materials in nature. Here we report on a synthetic strategy of constructing kagome systems via self-intercalation of Fe atoms into the van der Waals gap of FeSe2 via molecular beam epitaxy. Using low-temperature scanning tunneling microscopy, we unveil a kagome-like morphology upon intercalating a 2 × 2 ordered Fe atoms, resulting in a stoichiometry of Fe5Se8. Both the bias-dependent STM imaging and theoretical modeling calculations suggest that the kagome pattern mainly originates from slight but important reconstruction of topmost Se atoms, incurred by the nonequivalent subsurface Fe sites due to the intercalation. Our study demonstrates an alternative approach of constructing artificial kagome structures, which envisions to be tuned for exploring correlated quantum states.

An Anomalous Electron Configuration Among 3d Transition Metal Atoms.

Physical properties of materials are mainly determined by valence electron configurations, where different valence shells would induce divergent phenomena. In compounds containing Sc2+ , 3d electron occupancy is expected, the same as other transition metal atoms like Ti3+ . But this situation still awaits experimental verification in inorganic materials. Here, we selected ScS to measure the valence electron density and orbital population of Sc2+ through delicate quantitative convergent-beam electron diffraction. With the absence of 3d orbital features around Sc-atom sites and the nearly bare population of t2g orbital, the unintuitive occupation of 4s orbital in Sc2+ is concluded. It should be the first time to report such a special electron configuration in a transition metal compound, in which 4s rather than 3d orbital is preferred. Our findings reveal the distinct behavior of Sc and probable ways to modulate material properties by controlling electron orbitals.

Enhancement of Long-Lived Persistent Room-Temperature Phosphorescence and Anion Exchange with I- and SCN- via Metal-Organic Hybrid Formation.

An in-depth understanding of structure-property relationships and the construction of multifunctional stimuli-responsive materials are still difficult challenges. Herein, we discovered a 4,4'-bipyridinium derivative with both photochromism and dynamic afterglow at 77 K for the first time. A one-dimensional (1D) Cd(II) coordination polymer (1) assembled by only a 4,4'-bipyridinium derivative and cadmium chloride showed photochromism, room-temperature phosphorescence (RTP), and electrochromism. Interestingly, we found that 1 underwent single-crystal-to-single-crystal transformation during the anion exchange process, and the color of the crystal changed from colorless to yellow (1-SCN-) within 10 min. Complex 1 exhibited photochromism, whereas 1-SCN- did not. The difference in the photochromic behavior between the two complexes was ascribed to the electron transfer pathway between the carboxylate groups and viologen. The DFT calculation based on the crystal structure of 1-SCN- indicated that the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) were mainly located on bipyridine and cadmium atoms, eliminating the possibility of electron transfer, whereas for complex 1, electron transfer was probable from O and Cl atoms to pyridinium N atoms in viologen as demonstrated by density of states (DOS) calculations. In addition, complex 1 was successfully made into test paper for the rapid detection of I- and SCN- and displayed potential applications in inkless printing, multiple encryption, and anticounterfeiting.

Synergy of Ultrathin CoOx Overlayer and Nickel Single Atoms on Hematite Nanorods for Efficient Photo-Electrochemical Water Splitting.

To solve surface carrier recombination and sluggish water oxidation kinetics of hematite (α-Fe2 O3 ) photoanodes, herein, an attractive surface modification strategy is developed to successively deposit ultrathin CoOx overlayer and Ni single atoms on titanium (Ti)-doped α-Fe2 O3 (Ti:Fe2 O3 ) nanorods through a two-step atomic layer deposition (ALD) and photodeposition process. The collaborative decoration of ultrathin CoOx overlayer and Ni single atoms can trigger a big boost in photo-electrochemical (PEC) performance for water splitting over the obtained Ti:Fe2 O3 /CoOx /Ni photoanode, with the photocurrent density reaching 1.05 mA cm-2 at 1.23 V vs. reversible hydrogen electrode (RHE), more than three times that of Ti:Fe2 O3 (0.326 mA cm-2 ). Electrochemical and electronic investigations reveal that the surface passivation effect of ultrathin CoOx overlayer can reduce surface carrier recombination, while the catalysis effect of Ni single atoms can accelerate water oxidation kinetics. Moreover, theoretical calculations evidence that the synergy of ultrathin CoOx overlayer and Ni single atoms can lower the adsorption free energy of OH* intermediates and relieve the potential-determining step (PDS) for oxygen evolution reaction (OER). This work provides an exemplary modification through rational engineering of surface electrochemical and electronic properties for the improved PEC performances, which can be applied in other metal oxide semiconductors as well.

Principal component analysis of dental caries related factors among 3- to 5-year-old children in Urumqi City / 口腔疾病防治

Objective @#To explore dental caries-related factors among children aged 3-5 years in Urumqi City and to provide evidence for the etiological study and primary prevention of caries among local children. @*Methods @# A multistage stratified cluster sampling method was used to randomly select children aged 3-5 years in Urumqi City for oral examination, physical examination and questionnaire survey. Data were collected and analyzed by principal component logistic regression using SPSS 23.0 software.@*Results@#Principal component analysis showed that there were seven risk factors whose characteristic root value was greater than 1: oral hygiene habits, family education level, sugar intake, bedtime eating habits, age, gestational age, feeding mode, and cumulative contribution were 66.486% of the total variance. Principal component logistic regression analysis indicated that five factors, namely, oral hygiene habits (OR = 0.795, P = 0.044), family education level (OR = 0.667, P = 0.019), sugar intake (OR = 1.260, P = 0.006), bedtime eating habits (OR = 5.432, P<0.001) and age (OR = 0.676, P = 0.015), were closely related to early childhood caries, and they were statistically significant (P<0.05). @*Conclusion@#According to the principal component analysis, oral hygiene habits factor, family education level factor, sugar intake factor, bedtime eating habits factor and age factor were dental caries related factors among 3- to 5-year-old children in Urumqi City.

Boosting photocatalytic hydrogen production by creating isotype heterojunctions and single-atom active sites in highly-crystallized carbon nitride.

Carbon nitride-based photocatalysts hold an enormous potential in producing hydrogen. A strategy to simultaneously create isotype heterojunctions and active sites in highly-crystallized carbon nitride is anticipated to significantly boost the photocatalytic activity, but is yet to be realized. Herein, we find that cobalt salt added in the ionothermal synthesis can promote the phase transition of heptazine-based crystalline carbon nitride (CCN) to triazine-based poly(triazine imide) (PTI), rendering the creation of single-atom cobalt coordinated isotype CCN/PTI heterojunction. Co-CCN/PTI exhibits an appreciable apparent quantum yield of 20.88% at 425 nm for photocatalytic hydrogen production with a rate achieving 3538 µmol h-1 g-1 (λ > 420 nm), which is 4.8 times that of CCN and 27.6 times that of PTI. The high photocatalytic activity is attributed to the Type II isotype highly-crystallized CCN/PTI heterojunction for promoting charge carrier migration, and the single-atom Co sites for accelerating surface oxidation reaction.

Acupuncture combined with cognitive-behavioural therapy for insomnia (CBT-I) in patients with insomnia: study protocol for a randomised controlled trial.

INTRODUCTION: Insomnia affects physical and mental health due to the lack of continuous and complete sleep architecture. Polysomnograms (PSGs) are used to record electrical information to perform sleep architecture using deep learning. Although acupuncture combined with cognitive-behavioural therapy for insomnia (CBT-I) could not only improve sleep quality, solve anxiety, depression but also ameliorate poor sleep habits and detrimental cognition. Therefore, this study will focus on the effects of electroacupuncture combined with CBT-I on sleep architecture with deep learning. METHODS AND ANALYSIS: This randomised controlled trial will evaluate the efficacy and effectiveness of electroacupuncture combined with CBT-I in patients with insomnia. Participants will be randomised to receive either electroacupuncture combined with CBT-I or sham acupuncture combined with CBT-I and followed up for 4 weeks. The primary outcome is sleep quality, which is evaluated by the Pittsburgh Sleep Quality Index. The secondary outcome measures include a measurement of depression severity, anxiety, maladaptive cognitions associated with sleep and adverse events. Sleep architecture will be assessed using deep learning on PSGs. ETHICS AND DISSEMINATION: This trial has been approved by the institutional review boards and ethics committees of the First Affiliated Hospital of Sun Yat-sun University (2021763). The results will be disseminated through peer-reviewed journals. The results of this trial will be disseminated through peer-reviewed publications and conference abstracts or posters. TRIAL REGISTRATION NUMBER: CTR2100052502.

Electron-Deficient Zn-N6 Configuration Enabling Polymeric Carbon Nitride for Visible-Light Photocatalytic Overall Water Splitting.

Despite of suitable band structures for harvesting solar light and driving water redox reactions, polymeric carbon nitride (PCN) has suffered from poor charge transfer ability and sluggish surface reaction kinetics, which limit its photocatalytic activity for water splitting. Herein, atomically dispersed Zn-coordinated three-dimensional (3D) sponge-like PCN (Zn-PCN) is synthesized through a novel intermediate coordination strategy. Advanced characterizations and theoretical calculations well evidence that Zn single atoms are coordinated and stabilized on PCN in the form of Zn-N6 configuration featured with an electron-deficient state. Such an electronic configuration has been demonstrated contributive to promoted electron excitation, accelerated charge separation and transfer as well as reduced water redox barriers. Further benefited from the abundant surface active sites derived from the 3D porous structure, Zn-PCN realizes visible-light photocatalysis for overall water splitting with H2 and O2 simultaneously evolved at a stoichiometric ratio of 2:1. This work brings new insights into the design of novel single-atom photocatalysts by deepening the understanding of electronic configurations and reactive sites favorable to excellent photocatalysis for water splitting and related solar energy conversion reactions.

Clinical Manifestation of Cardiac Rupture in Patients with ST-Segment Elevation Myocardial Infarction: Early Versus Late Primary Percutaneous Coronary Intervention.

Background: Cardiac rupture is one of the fatal complications of ST-Segment Elevation Myocardial Infarction (STEMI) in the primary percutaneous coronary intervention (PPCI) era. The present study aims to identify risk factors of cardiac rupture among patients suffering from STEMI, treated with early and late PPCI. Methods: This is a multicenter retrospective cohort study involving STEMI patients with cardiac rupture (CR group), matched with STEMI patients without CR (control group) in a 1:5 ratio. They were divided into the early (≤ 6 h) and the late (> 6 h) PCI groups. Multivariable logistic regression was utilized to identify risk factors for cardiac rupture. Results: Seventy-four patients in the CR and 370 in the control group were included. Multivariable regression identified lateral infarction (OR = 11.89, 95% CI 2.22-63.81, p < 0.01) in the early PCI phase as a significant risk factor for cardiac rupture. Thrombolysis in myocardial infarction (TIMI) grade 0-1 (early PCI: OR = 4.16, 95% CI 1.33-13.0, p = 0.01; late PCI: OR = 4.46, 95% CI 1.59-12.54, p < 0.01) was a risk factor for both early and late PCI groups. In contrast, TIMI grade 2 was associated with a higher rupture risk within the late (OR = 16.87, 95% CI 3.83-74.19, p < 0.001) but not for the early (OR = 5.44, 95% CI 0.76-39.07, p = 0.09) PCI groups. STEMI combined with Killip IV was associated with a higher rupture risk for the late PCI group (OR = 1.43, 95% CI 1.03-1.99, p = 0.04). Intra-aortic balloon pump (IABP) was protective against cardiac rupture within early PPCI (OR = 0.18, 95% CI 0.04-0.89, p = 0.04). In contrast, glycoprotein IIb/IIIa inhibitors were associated with lower rupture risks in both the early and late groups (early PCI: OR = 0.38, 95% CI 0.17-0.87, p = 0.02; late PCI: OR = 0.33, 95% CI 0.15-0.75, p < 0.01). Conclusions: No reflow or slow blood flow is associated with a higher risk of cardiac rupture in early and late PCI patients. Glycoprotein IIb/IIIa inhibitors are beneficial in preventing heart rupture, and the use of IABP in early PPCI is also helpful in preventing heart rupture.

Coherent coupling of metamaterial resonators with dipole transitions of boron acceptors in Si.

We investigate the coherent coupling of metamaterial resonators with hydrogen-like boron acceptors in Si at cryogenic temperatures. When the resonance frequency of the metamaterial, chosen to be in the range 7-9 THz, superimposes the transition frequency from the ground state of the acceptor to an excited state, Rabi splitting as large as 0.4 THz is observed. The coherent coupling shows a feature of cooperative interaction, where the Rabi splitting is proportional to the square root of the density of the acceptors. Our experiments may help to open a possible route for the investigation of quantum information processes employing strong coupling of dopants in cavities.

Real-space measurement of orbital electron populations for Li1-xCoO2.

The operation of lithium-ion batteries involves electron removal from and filling into the redox orbitals of cathode materials, experimentally probing the orbital electron population thus is highly desirable to resolve the redox processes and charge compensation mechanism. Here, we combine quantitative convergent-beam electron diffraction with high-energy synchrotron powder X-ray diffraction to quantify the orbital populations of Co and O in the archetypal cathode material LiCoO2. The results indicate that removing Li ions from LiCoO2 decreases Co t2g orbital population, and the intensified covalency of Co-O bond upon delithiation enables charge transfer from O 2p orbital to Co eg orbital, leading to increased Co eg orbital population and oxygen oxidation. Theoretical calculations verify these experimental findings, which not only provide an intuitive picture of the redox reaction process in real space, but also offer a guidance for designing high-capacity electrodes by mediating the covalency of the TM-O interactions.