Search

A study was conducted to analyze Raman spectra from saturated water vapor to the supercritical fluid. The non-H-bonded OH stretching modes were assumed to correlate with the integrated intensity above the isobestic frequency and the dimer. Density-normalized Raman OH stretching vapor intensities were determined from 255 to 314 degrees C. In addition, density normalization was associated with the division of intensities by the density of the vapor.

XANES and EXAFS spectroscopic studies of the influence of bacterial microorganisms such as Bacillus subtilis on the oxidation state of Se indicate that a reduction of Se(IV) to red elemental Se takes place with the aid of these organisms. This technique enables the isolation of Se(IV) from other contaminated aqueous substances through microbial metabolism.

The application of UV-free electron laser photoelectron emission microscopy (UV-FEL PEEM) to measure the threshold photoelectron spectrum and photoionization potential for human eumelanosomes is described. The UV-FEL PEEM images collected on human eumalenasomes isolated from black hair show that the organelle is photoionized by UV-B radiation and the photoionization threshold is determined to be 4.6 plusmn 0.2eV.

The use of porous media in combustion processes has beenwidelyresearched and investigated. In this paper, the effect of employingporous media on microcombustion was studied using numerical simulation.Simulated results demonstrated good agreement with the experimentalresults, and thus validated the model. Analysis has been carried outwith dimensional analysis and basic theorem which incorporates theBiot number in an attempt to fundamentally understand the effectsbrought about by equivalence ratio, thermal conductivity of the solidmatrix and mass flow rate on microthermophotovoltaic (TPV) performance.One of the key results has demonstrated that the higher the equivalenceratio of the fuel/air mixture, the higher will be the mean wall temperature.A peak-shift phenomenon has been observed, where the position of maximumflame temperature shifts downstream away from the inlet at lower equivalenceratio. Results from the Biot number analysis has indicated that thehigher the thermal conductivity of the wall is, the more uniform thewall temperature distribution will be. A lower mean wall temperatureis obtained when the thermal conductivity of the solid matrix is installedat 50 W/mK, whereas higher mean wall temperatures can be achievedfor either small (5 W/mK) or very large (500 W/mK) thermal conductivity.It is clearly evidenced that the performance of microcombustors canbe markedly enhanced by incorporating a thermally effective porousmedium. The theoretical understanding gained from the present researchwill facilitate the design of more energy efficient, stable and bettercontrollable portable TPV on-field power systems. [ABSTRACT FROM AUTHOR]

Developing ultralow-κ (dielectric constant) polyimides (PIs) that are mechanically robust while also being optically transparent is challenging. For the first time, we report a nanoporous PI film with an ultralow κ of 1.8 in combination with a tensile strength of up to 180 MPa, a Young's modulus of up to 6 GPa, and a transmittance of ∼88%. This is achieved by direct nanowelding of a porous electrospun PI nanofiber membrane using a simple mixture of ethanol-dominating DMAc. Benefiting from the effective evaporation of the antisolvent ethanol upon heating, the proposed nanowelding approach allows for the localized surface dissolution of the PI nanofibers, which enables the dissolved PI to "glue" the nanofibers and occupy vacant space in the membrane, resulting in the formation of a dense but nanoporous self-reinforced nanocomposite film. Our findings provide a renewed understanding of the potential of electrospun nanofibrous materials, and the underlying principle can hopefully be applied to other commodity polymers.

Under solvothermal conditions, three 3D lanthanide metal-organic frameworks (Ln-MOFs): [Eu(H 2 DHTA) 1.5 (DMF) 2 ]·DMF ( 1 ), [Eu(H 2 DHTA) 0.5 (DHTA) 0.5 (DMF)(H 2 O)]·2H 2 O ( 2 ), and Eu(HCOO) 3 ( 3 ) (H 4 DHTA = 2,5-dihydroxyterephthalic acid) have been synthesized by different reaction times. Interestingly, induced by reaction time, compounds 1-3 underwent a two-step dissolution and recrystallization structural transformation (DRST) reaction. Investigations on the DRST processes were carried out, and the transformation pathway was deduced, which was verified by XRD analyses. Notably, compound 2 demonstrates pronounced luminescence as well as high stability in water and other organic solvents. The fluorescent detection of furan antibiotics can serve as turn-off effects, and glutamic acid (Glu), aspartic acid (Asp), and riboflavin (VB 2 ) can serve as the turn-on effect. To explain the enhancing and quenching mechanisms, XRD, UV-visible absorption spectroscopy, electrochemistry, IR spectra, theoretical calculation, fluorescence lifetimes, and XPS were discussed. Additionally, MOF-coated test strips were utilized to detect these analytes, exhibiting excellent agreement with fluorescence spectroscopy. This work provides an example for more effective designs to employ Ln-MOFs as multiresponsive fluorescent sensors for detection of environmental pollutants in aqueous solution.

Unfavorable phenotypes characterized by low immunogenicity and acidity within the tumor microenvironment (TME) contribute to immunosuppression and therapeutic resistance. Herein, we rationally synthesized a multifunctional nanoregulator by encapsulating DOX and erianin into calcium carbonate (CaCO 3 )-based nanoparticles using a modified double emulsion method. The DOX and erianin-loaded CaCO 3 -based nanoparticles, termed DECaNPs, could effectively induce the calcium overload by triggering calcium influx and absorbing CaCO 3 nanoparticles. Additionally, DECaNPs also neutralize the acidic TME by interacting with extracellular protons and limiting lactic acid production, a result of metabolic remodeling in cancer cells. As a result, DECaNPs elicit cellular oxidative stress damage, which mediates the activation of ferroptosis/apoptosis hybrid pathways, and profound immunogenic cell death. Treatment with DECaNPs could inhibit the growth of tumors by promoting oxidative stress, acid neutralization, metabolic remodeling, and protective antitumor immunity in vivo . In addition, DECaNPs could synergistically amplify the antitumor effects of αPD-L1 in a bilateral tumor model by eliciting systemic immune responses. In all, our work presents the preparation of CaCO 3 -based nanoregulators designed to reverse the unfavorable TME and enhance αPD-L1 immunotherapy through multiple mechanisms.

Exploring efficient and stable halide perovskite-based photocatalysts is a great challenge due to the balance between the photocatalytic performance, toxicity, and intrinsic chemical instability of the materials. Here, the environmentally friendly lead-free perovskite Cs 2 AgBiBr 6 confined in the mesoporous TiO 2 crystal matrix has been designed to enhance the charge carrier extraction and utilization for efficient photocatalytic rifampicin degradation. The as-prepared Cs 2 AgBiBr 6 /TiO 2 catalyst was stable in air for over 500 days. An S-scheme heterojunction was formed between the (004) plane of Cs 2 AgBiBr 6 and the (101) plane of TiO 2 through the Bi-O-Br bonds. The built-in electric field at the interface efficiently promoted the photoinduced charge separation and carrier extraction. The Cs 2 AgBiBr 6 /TiO 2 -200 showed a 92.83% degradation efficiency of rifampicin within 80 min under simulated sunlight illumination (AM 1.5G 100 mW cm -2 ). This work offers an effective way for the construction of halide perovskite-based photocatalysts with high photocatalytic performance, good stability, and low toxicity simultaneously.

In this paper, heterogeneous cobalt phosphosulfide (Co 4 S 3 /Co 2 P) nanocrystals anchoring on few-layered MXene nanosheets (MXene@Co 4 S 3 /Co 2 P) were prepared by in situ growth and the subsequent high-temperature phosphorization/sulfidation processes. Thanks to the synergistic effect and the abundant phase interfaces of Co 4 S 3 , Co 2 P, and MXene, the electron transfer and Na + diffusion processes were greatly accelerated. Meanwhile, the high electrical conductivity of MXene nanosheets and the heterogeneous structure of Co 4 S 3 /Co 2 P effectively avoided the MXene restacking and the agglomeration of phosphosulfide particles, thus mitigating volumetric expansion during charging and discharging. The results show that the MXene@Co 4 S 3 /Co 2 P heterostructure presents good rate capability (251.08 mAh g -1 at 1 A g -1 ) and excellent cycling stability (198.69 mAh g -1 after 407 cycles at 5 A g -1 ). Finally, the storage mechanism of Na + in the heterostructure and the multistep phase transition reaction were determined by ex situ X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS), and X-ray photoelectron spectroscopy (XPS) analyses. This study provides a new perspective on the formation of metal phosphosulfide and MXene hybrids with multiple heterointerfaces as well as demonstrates MXene@Co 4 S 3 /Co 2 P composites as the promising anode material in sodium-ion batteries.

The overexpression of NEU1 has recently been certified as being associated with myocardial infarction. However, the pursuit of an efficacious human NEU1 (hNEU1) inhibitor remains challenging, and viral NEU1 (viNEU1) inhibitor drugs are significantly weaker in terms of hNEU1 inhibition. Recognizing that hNEU1 is located within the lysosome, we designed a series of lysosome-targeting compounds, derived from oseltamivir, aimed at hNEU1 inhibition. Among these compounds, OsMo exhibits the most potent activity. Our findings reveal that OsMo accumulates within lysosomes and releases its pharmacophore via enzymatic catalysis. OsMo enhances hNEU1 inhibition by accumulating pharmacophores at the target site. OsMo exhibits improved regulation of abnormal autophagy during myocardial injury, demonstrating superior efficacy in treating myocardial infarction in vivo . Furthermore, OsMo exhibits acceptable pharmacokinetic parameters. Importantly, the development of molecules with lysosome-targeting abilities represents a promising avenue for addressing myocardial injuries linked to hNEU1 overexpression.

Carbene-catalyzed [3 + 3] annulation of enals and vinyl sulfoxonium ylides has been demonstrated. This method efficiently synthesizes a range of 2-sulfenylidene-3-cyclohexen-1-ones with high atom economy. Notably, the presence of the sulfoxonium ylide moiety in the obtained products significantly enhances their potential for further synthetic transformations.

Oxide semiconductor thin-film transistors (TFTs) have shown great potential in emerging applications such as flexible displays, radio-frequency identification tags, sensors, and back-end-of-line compatible transistors for monolithic 3D integration beyond their well-established flat-plane display technology. To meet the requirements of these appealing applications, high current drivability is essential, necessitating exploration in materials science and device engineering. In this work, we report for the first time on a simple solution-based superacid (SA) treatment to enhance the current drivability of top-gate TiO 2 TFTs with a gate-offset structure. The on-current of these transistors is limited by the relatively low mobility of TiO 2 due to its d-orbital conduction nature. It is found that the on-current of TiO 2 TFTs is nearly doubled via a quick dip in a SA solution at room temperature in ambient air. A series of experiments, including comparative I - V measurements of TFTs with different treatments and gate structures, C - V measurements, X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, and device simulation, were performed to uncover the underlying reason for the current enhancement. It is believed that the protons (H + ) from SA are doped into the offset region of TiO 2 TFTs, forming an electron double layer and thus boosting the on-current, with the top gate serving as a self-aligned mask for ionic doping. Furthermore, the ionic size and the proportion of the offset region to the channel play crucial roles in the effectiveness of ionic doping, while the position of the incorporated ions, whether in the channel or dielectric, may result in distinct shifts in the turn-on voltage ( V ON ) and affect the functionality of ionic doping. This study provides a pathway for enhancing the current drivability of TiO 2 TFTs via selective ionic doping enabled by SA treatment and deepens our understanding of ion incorporation in electronic devices. This approach could be applicable to other material systems and may also benefit TFTs with miniaturized dimensions, thus opening up unprecedented opportunities for TiO 2 TFTs in future applications requiring high current drivability.

The development of intelligent multifunctional nanopesticides featuring enhanced foliage affinity and hierarchical target release is increasingly pivotal in modern agriculture. In this study, a novel cationic amphiphilic comb-shaped polymer, termed PEI-TA, was prepared via a one-step Michael addition between low-molecular-weight biodegradable polyethylenimine (PEI) and tetradecyl acrylate (TA), followed by neutralization with acetic acid. Using the emulsifier PEI-TA, a positively charged avermectin (AVM) nanoemulsion was prepared via a phase inversion emulsification process. Under optimal formulation, the obtained AVM nanoemulsion (defined as AVM@PEI-TA) demonstrated exceptional properties, including small size (as low as 67.6 nm), high encapsulation efficiency (up to 87.96%), and high stability toward shearing, storage, dilution, and UV irradiation. The emulsifier endowed AVM@PEI-TA with a pronounced thixotropy, so that the droplets exhibited no splash and bounce when they were sprayed on the cabbage leaf. Owing to the electrostatic attraction between the emulsifier and the leaf, AVM@PEI-TA showed improved leaf adhesion, better deposition, and higher washing resistance in contrast to both its negatively charged counterpart and AVM emulsifiable concentrate (AVM-EC). Compared to the large-sized particles, the small-sized particles of the AVM nanoemulsion more effectively traveled long distances through the vascular system of veins after entering the leaf apoplast. Moreover, the nanoparticles lost stability when exposed to multidimensional stimuli, including pH, temperature, esterase, and ursolic acid individually or simultaneously, thereby promoting the release of AVM. The release mechanisms were discussed for understanding the important role of the emulsifier in nanopesticides.

CoSb 3 -based skutterudites have great potential as midtemperature thermoelectric (TE) materials due to their low cost and excellent electrical and mechanical properties. Their application, however, is limited by the high thermal conductivity and the degradation of TE performance at elevated temperatures, attributed to the adverse effects of bipolar diffusion. Herein, a series of Se y Co 4 Sb 12- x Te x compounds were successfully synthesized by combining a solid-state reaction and spark plasma sintering techniques to mitigate these challenges. It was found that doping Te at the Sb sites effectively enhanced the carrier concentration and suppressed the bipolar effect to obtain a superior power factor of ∼43 μW cm -1 K -2 . Furthermore, due to the low resonant frequency of Se, filling voids of CoSb 3 with Se achieved a low lattice thermal conductivity of 1.55 W m -1 K -1 . Nevertheless, Se filling introduced additional holes, reducing the carrier concentration without a significant detriment of the carrier mobility. As a result, a maximum figure of merit of 1.23 was achieved for Se 0.1 Co 4 Sb 11.55 Te 0.45 at 773 K. This work provides a valuable guidance for selecting appropriate filling and doping components to achieve synergistic optimization of the acoustics and electronics of CoSb 3 -based skutterudites.

Due to the unique photosensitivity of silver compounds, they exhibit good photocatalytic activity as photocatalysts in the degradation of water pollutants. However, silver compounds have poor cycling stability and are prone to decomposition and reaction under light to form metallic silver, which greatly limits their practical application. Herein, a (2-(2-(diphenylphosphaneyl)ethyl)-9-methyl-1.10-phenanthroline (PSNNP)) pincer ligand was designed for stabilizing the central metal. The in situ-formed PSNNP ligand could be readily generated in one pot with the participation of silver halides. The reaction of silver halides with dppeda ( N , N , N ', N '-tetra(diphenylphosphanylmethyl)ethylene diamine) in the presence of dmp (2,9-dimethyl-1,10-phenanthroline) in acetonitrile afforded complexes Ag 2 X 2 (PSNNP) 2 (complexes 1 , 2 ) (X = Cl, Br). Single-crystal X-ray diffraction shows that the tridentate coordination of the pincer ligand provides strong binding with metal centers and leads to high stability of the pincer metal unit. The removal rate of rhodamine B (RhB) by complexes 1 and 2 can reach up to 100%, demonstrating an excellent photocatalytic degradation performance for organic dyes. The important effect of PSNNP ligands on photocatalytic properties after coordination with central metals was studied through experiments and discrete Fourier transform (DFT) calculations. The photocatalytic reaction mechanism of complexes 1 and 2 was also studied. This result provides an effective pathway for the first synthesis of PSNNP and interesting insights into photocatalytic degradation chemistry.

Herein, we report an unprecedented P(NMe 2 ) 3 -mediated reductive insertion of 1,2-dicarbonyl compounds including α-keto esters and isatins into phthalic anhydride-derived alkenes and phthalic anhydrides, which furnishes the corresponding isochroman-1-ones and isochroman-1,4-diones, respectively, in moderate to excellent yields with high chemo- and regioselectivity. Furthermore, the asymmetric version of the ring expansion reaction could be realized by using a chiral auxiliary strategy. Mechanistically, the nucleophilic attack of the Kukhtin-Ramirez adduct, generated from P(NMe 2 ) 3 and 1,2-dicarbonyl compound, to the anhydride derivative, followed by a cascade ring-opening and ring-closure process, affords the ring expansion product. The reaction represents a novel metal-free carbon insertion ring expansion of aliphatic rings and also the first [1 + 5] annulation involving the Kukhtin-Ramirez adducts.

Over the past decade, [ 68 Ga]Ga-FAPI-04 positron emission tomography (PET)/CT imaging has been widely used for the treatment of various tumors. However, the application of 99m TC-labeled fibroblast activation protein inhibitors in tumors has been less studied. Our team previously demonstrated the safe biological distribution of [ 99m Tc]Tc-DP-FAPI in the human body. Based on this, this study reports the accuracy of [ 99m Tc]Tc-DP-FAPI in the imaging diagnosis of gastrointestinal tumors and compares it with that of [ 68 Ga]Ga-FAPI-04 to evaluate the differences. A total of 24 patients with clinically diagnosed gastrointestinal tumors were prospectively included. All patients received [ 99m Tc]Tc-DP-FAPI quantitative SPECT/CT imaging on the first day and [ 68 Ga]Ga-FAPI-04 PET/CT imaging on the second day. And the effectiveness of the two imaging probes in detecting suspicious lesions was analyzed and compared. The primary tumors of all 24 patients were well detected by two imaging probes, and the sensitivity of [ 99m Tc]Tc-DP-FAPI and [ 68 Ga]Ga-FAPI-04 to the primary lesions was 100%. [ 99m Tc]Tc-DP-FAPI examined 21 lymph nodes with a sensitivity and specificity of 32.8% and 10.9%, and [ 68 Ga]Ga-FAPI-04 detected 57 lymph nodes with a sensitivity and specificity of 89.1% and 67.2%, respectively. Three distant metastases were detected by [ 99m Tc]Tc-DP-FAPI and nine metastases by [ 68 Ga]Ga-FAPI-04. The study showed that [ 99m Tc]Tc-DP-FAPI is highly sensitive to detecting primary lesions of gastrointestinal tumors. Compared with [ 68 Ga]Ga-FAPI-04, [ 99m Tc]Tc-DP-FAPI has the same sensitivity in detecting primary tumors but has certain limitations in detecting metastases. [ 99m Tc]Tc-DP-FAPI is of great value for preliminary screening of tumor lesions and early diagnosis of disease in patients who are suspected of having gastrointestinal tumors.

The neurotoxicity of bisphenol A (BPA) exposure has been confirmed in vitro and in vivo , and inflammatory response is considered the main pathway. Green tea is a healthy life habit as it is rich in various anti-inflammatory components. To confirm that green tea diet is an effective measure to antagonize BPA-induced neurotoxicity, mice were treated with 0.5 and 5000 μg/kg/day of BPA from postnatal days (PNDs) 10-50 and supplemented with green tea on PND 21. From PND 51, behavioral tests were conducted on mice to assess their emotional, cognitive, and spatial learning memory capabilities. The open field test and elevated plus maze test indicated anxiety-like behaviors induced by BPA. Interestingly, green tea diet significantly alleviated BPA-induced anxiety-like behaviors. Meanwhile, the green tea diet effectively reversed BPA-induced microglia activation and morphological changes in the hippocampus of mice. Molecularly, green tea inhibited hippocampal neuroinflammation of mice by reducing BPA-induced expressions of NLRP3, ASC, cleaved-caspase-1, GSDMD-N, IL-6, and IL-1β, as well as significantly reducing the expression of Bak1, Bax, caspase-9, and Cytc c genes ( p < 0.05). Molecular docking suggests that various anti-inflammatory components of green tea can competitively bind to the estrogen receptors with BPA. In general, a green tea diet alleviates BPA-induced emotional disorders by inhibiting microglial polarization and hippocampal pyroptosis, indicating its effective antagonistic ability against the neurotoxicity induced by environmental BPA exposure.

Porous spindle-knot structures have been found in many creatures, such as spider silk and the root of the soybean plant, which show interesting functions such as droplet collection or biotransformation. However, continuous fabrication of precisely controlled porous spindle-knots presents a big challenge, particularly in striking a balance among good structural controllability, low-cost, and functions. Here, we propose a concept of a fiber-microfluidics phase separation (FMF-PS) strategy to address the above challenge. This FMF-PS combines the advantages of a microchannel regulated Rayleigh instability of polymer solution coated onto a fiber with the nonsolvent-induced phase separation of the polymer solution, which enables continuous and cost-effective production of porous spindle-knot fiber (PSKF) with well-controlled size and porous structures. The critical factors controlling the geometry and the porous structures of the spindle-knot by FMF-PS have been systematically investigated. For applications, the PSKF exhibited faster water droplet nucleation, growth, and maximum water collection capability, compared to the control samples, as revealed by in situ water collection growth curves. Furthermore, high-level fabrics of the PSKFs, including a two-dimensional network and three-dimensional architecture, have been demonstrated for both large-scale water collection and art performance. Finally, the PSKF is demonstrated as a programmable building block for surface nanopatterning.

Current studies have demonstrated that microbe-host interactions (MHIs) play important roles in human public health. Therefore, identifying the interactions between microbes and hosts is beneficial to understanding the role of the microbiome and their underlying mechanisms. However, traditional wet-lab experimental approaches are insufficient for large-scale exploration of candidate microbes, as they are costly, laborious, and time-consuming. Thus, it is critical to prioritize microbe-interacting hosts by computational approaches for further biological experimental validation. In this work, we proposed a novel deep learning-based method called MHIPM, to predict MHIs by utilizing multisource biological information. Specifically, we first constructed a heterogeneous microbial network that consisted of human proteins, viruses, bacteriophages (phages), and pathogenic bacteria. Next, we used one of the largest protein language models, ESM-2, and a document embedding model, doc2vec, combined with a self-attention mechanism to extract the interview features from protein sequences. Then, an inductive learning-based model, GraphSAGE, was used to capture the intraview features from the heterogeneous network. Experimental results on three prediction tasks indicated that the MHIPM model consistently achieved better performance than seven baseline algorithms and its four variants. In addition, case studies and molecular docking experiments for two human proteins further confirmed the effectiveness of our model. In conclusion, MHIPM is an efficient and robust method in predicting MHIs and provides plausible candidate microbes for biological experiments. MHIPM is available at https://github.com/JIENWU/MHIPM.

Obtaining reliable and informative DNA data from soil samples is challenging due to the presence of interfering substances and typically low DNA yields. In this work, we prepared poly(ethylene glycol)-modified magnetic particles (PEG@Fe 3 O 4 ) for DNA purification. The particles leverage the facilitative effect of calcium ions (Ca 2+ ), which act as bridges between DNA and PEG@Fe 3 O 4 by coordinating with the phosphate groups of DNA and the hydroxyl groups on the particles. The addition of 2-propanol further enhances this Ca 2+ -mediated DNA adsorption by inducing a conformational change from the B-form to the more compact A-form of DNA. PEG@Fe 3 O 4 demonstrates a DNA adsorption capacity of 144.6 mg g -1 . When applied to the extraction of genomic DNA from soil samples, PEG@Fe 3 O 4 outperforms commercial kits and traditional phenol-chloroform extraction methods in terms of DNA yield and purity. Furthermore, we developed a 16-channel automated DNA extraction device to streamline the process and reduce the extraction time. The successful amplification of target bacterial and fungal amplicons underscores the potential of this automated, device-assisted method for studying soil microbial diversity.

Electrical double layer (EDL) plays a crucial role in colloidal chemistry, which can be modified by changing the pH and ionic strength of a solution. Even though EDL is well-recognized, there are limited studies exploring interactions between two-dimensional (2D) and zero-dimensional nanoparticles. Herein, we demonstrate a simple pH-based approach to control the EDL of boron nitride nanosheets (BNNSs) and gold nanoparticles (AuNPs) that plays a crucial role in their interaction, displaying a one-way gate effect. We observed that as the EDL decreases, AuNPs can come into closer interaction with BNNSs, and this also resulted in a deceleration of the aggregation process of AuNPs when functionalized with l-cysteine. This work provides a fundamental understanding of how modulation of the EDL of 2D nanomaterials can be achieved through functionalizing strategies.

The particle-particle random phase approximation (ppRPA) within the hole-hole channel was recently proposed as an efficient tool for computing excitation energies of point defects in solids [ J. Phys. Chem. Lett. 2024, 15, 2757-2764]. In this work, we investigate the application of ppRPA within the particle-particle channel for predicting correlated excited states of point defects, including the carbon-vacancy (VC) in diamond, the oxygen-vacancy (VO) in magnesium oxide (MgO), and the carbon dimer defect (C B C N ) in two-dimensional hexagonal boron nitride (h-BN). Starting from a density functional theory calculation of the ( N - 2)-electron ground state, vertical excitation energies of the N -electron system are obtained as the differences between the two-electron addition energies. We show that active-space ppRPA with the B3LYP functional yields accurate excitation energies, with errors mostly smaller than 0.1 eV for tested systems compared to available experimental values. We further develop a natural transition orbital scheme within ppRPA, which provides insights into the multireference character of defect states. This study, together with our previous work, establishes ppRPA as a low-cost and accurate method for investigating excited-state properties of point defect systems.

ConspectusZinc-ion batteries (ZIBs) are highly promising for large-scale energy storage because of their safety, high energy/power density, low cost, and eco-friendliness. Vanadium-based compounds are attractive cathodes because of their versatile structures and multielectron redox processes (+5 to +3), leading to high capacity. Layered structures or 3-dimensional open tunnel frameworks allow easy movement of zinc-ions without breaking the structure apart, offering superior rate-performance. However, challenges such as dissolution and phase transformation hinder the long-term stability of vanadium-based cathodes in ZIBs. Although significant research has been dedicated to understanding the mechanisms and developing high-performance vanadium-based cathodes, uncertainties still exist regarding the critical mechanisms of energy storage and dissolution, the actual active phase and the specific optimization strategy. For example, it is unclear whether materials such as α-V 2 O 5 , VO 2 , and V 2 O 3 serve as the active phase or undergo phase transformations during cycling. Additionally, the root cause of V-dissolution and the role of byproducts such as Zn 3 (OH) 2 V 2 O 7 ·2H 2 O in ZIBs are debated.In this account, we aim to outline a clear and comprehensive roadmap for V-based cathodes in ZIBs. On the basis of our studies, we analyzed intrinsic crystal structures and their correlation with performance to guide the design of V-based materials with high-capacity and high-stability for ZIBs. Then, we revealed the underlying mechanisms of energy storage and instability, enabling more effective design and optimization of V-based cathodes. After identifying the key challenges, we proposed effective design principles to achieve high cycling performance of V-based cathodes and outlined future development directions toward their practical application. Vanadium-based compounds include [VO 4 ] tetrahedrons, [VO 5 ] square pyramids, and [VO 6 ] octahedra, which are connected through a cocorner, coedge and coplane. The [VO 4 ] tetrahedron is inactive, and the [VO 5 ] square pyramid is unstable in aqueous solutions because water attacks the exposed vanadium, whereas stable [VO 6 ] octahedra are desirable because of their ability to reduce from +5 to +3 with minimal structural distortion. Therefore, high-performance vanadium-based oxides in ZIBs should maintain intact [VO 6 ] octahedra while avoiding [VO 4 ] tetrahedra or [VO 5 ] square pyramids. The energy storage mechanism involves H 2 O/H + /Zn 2+ coinsertion. The existence of interlayer water in V-based cathodes significantly improves the rate and cycling performance by expanding galleries, screening Zn 2+ electrostatically via solvation, reducing ion diffusion energy barriers, and increasing layer flexibility. The insertion of H + /Zn 2+ and the instability of V-based cathodes lead to the formation of byproducts such as basic zinc salts (i.e., Zn 4 SO 4 (OH) 6 ·nH 2 O) and dead vanadium (Zn 3 (OH) 2 V 2 O 7 ·2H 2 O), whose reversibility strongly affects long-term stability. To increase the cycling stability of vanadium-based cathodes, strategies such as electrolyte modulation and coating have been proposed to decrease water attack on the surface of V-oxides, thereby affecting the formation of byproducts. Additionally, in situ electrochemical transformation, ion preintercalation, and ion exchange were explored to prepare intrinsically stable V-based cathodes with enhanced performance. Furthermore, future research should focus on revealing atomic-scale mechanisms through advanced in situ characterization and theoretical calculations, enhancing rate-performance by facilitating ion/electron diffusion, promoting cycling stability by developing highly stable cathodes and refining interface engineering, and scaling up vanadium-based cathodes for practical ZIB applications.