Search

To realize the full potential of transition metal dichalcogenides interfaced with bulk semiconductors for solar energy applications, fast photoinduced charge separation, and slow electron–hole recombination are needed. Using a combination of time-domain density functional theory with nonadiabatic molecular dynamics, we demonstrate that the key features of the electron transfer (ET), energy relaxation and electron–hole recombination in a MoS2–TiO2 system are governed by the weak van der Waals interfacial interaction and interface polarization. Electric fields formed at the interface allow charge separation to happen already during the photoexcitation process. Those electrons that still reside inside MoS2, transfer into TiO2 slowly and by the nonadiabatic mechanism, due to weak donor–acceptor coupling. The ET time depends on excitation energy, because the TiO2 state density grows with energy, increasing the nonadiabatic transfer rate, and because MoS2 sulfur atoms start to contribute to the photoexcited state at higher energies, increasing the coupling. The ET is slower than electron–phonon energy relaxation because the donor–acceptor coupling is weak, rationalizing the experimentally observed injection of primarily hot electrons. The weak van der Waals MoS2–TiO2 interaction ensures a long-lived charge separated state and a short electron–hole coherence time. The injection is promoted primarily by phonons within the 200–800 cm–1 range. Higher frequency modes are particularly important for the electron–hole recombinations, because they are able to accept large amounts of electronic energy. The predicted time scales for the forward and backward ET, and energy relaxation can be measured by time-resolved spectroscopies. The reported simulations generate a detailed time-domain atomistic description of the complex interplay of the charge and energy transfer processes at the MoS2/TiO2 interface that are of fundamental importance to photovoltaic and photocatalytic applications. The results suggest that even though the photogenerated charge-separated state is long-lived, the slower charge separation, compared to the electron–phonon energy relaxation, can present problems in practical applications. [ABSTRACT FROM AUTHOR]

Sodium ion batteries (SIBs) are considered to be a promising alternative to lithium ion batteries because of the high abundance of sodium. However, the scarcities of suitable anode materials severely hamper the development of SIBs. Here, we synthesized a GeP5/C composite with binary sodium-reactive components on a large scale. Theoretically, it can promise a capacity of 1888 mA h g−1 or 6891 mA h cm−3, which is the best record in anodes for SIBs reported so far. In practice, the GeP5/C showed a low potential of ≈0.4 V vs. Na+/Na with a smooth charge/discharge profile. It delivered a large reversible capacity of 1250 mA h g−1 with a first coulombic efficiency of 93%. Electrochemical-mechanism studies suggested that the formation of a GeP5 phase endowed a high first coulombic efficiency and synergetic effect between the sodiation of Ge and P. This effect smoothly leveled the multistep plateaus and effectively reduced the polarization between charge/discharge. When applied to a full cell by coupling a Na3V2(PO4)3/C cathode, the assembled Na3V2(PO4)3//GeP5 full cell showed a large capacity of 800 mA h g−1 with a high average output voltage of 2.65 V. The excellent sodium-storage performances of GeP5/C will ensure commercial utilization in future SIBs. [ABSTRACT FROM AUTHOR]

Layered transition metal (TM) oxides of the stoichiometry NaxMO2 (M = TM) have shown great promise in sodium‐ion batteries (SIBs); however, they are extremely sensitive to moisture. To date, most reported titanium‐based layered anodes exhibit a P2‐type structure. In contrast, O3‐type compounds are rarely investigated and their synthesis is challenging due to their higher percentage of unstable Ti3+ than the P2 type. Here, a pure phase and highly crystalline O3‐type Na0.73Li0.36Ti0.73O2 with high performance is successfully proposed in SIBs. This material delivers a reversible capacity of 108 mAh g−1 with a stable and safe potential of 0.75 V versus Na/Na+. In situ X‐ray diffraction reveals that this material does not undergo any phase transitions and exhibits a near‐zero volume change upon Na+ insertion/de‐insertion, which ensures exceptional long cycle life over 6000 cycles. Importantly, it is found that this O3‐Na0.73Li0.36Ti0.73O2 shows superior moisture stability, even when immersed into water, which are both elusive for conventional layered TM oxides in SIBs. It is believed that the small interlayer distance and high occupation of interlayer vacancy promise such unprecedented water stability. [ABSTRACT FROM AUTHOR]

Plant-associated microbial communities strongly relate to host health and productivity. Still, our knowledge of microbial community spatiotemporal patterns in soil-plant continuum is largely limited. Here, we explored the spatiotemporal dynamics of fungal communities across multiple compartments (phyllosphere, leaf endosphere, soil, rhizosphere, rhizoplane, and root endosphere) of rubber tree in two contrasting seasons collected from Hainan Island and Xishuangbanna. Our results demonstrate that the fungal alpha and beta diversity exhibited distinct pattern; the alpha diversity is highly dependent on seasonal changes, while beta diversity only showed a geographical variation pattern. The season-specific environmental factors (e.g., climatic factors) were the most important factors in shaping fungal alpha diversity across the soil-plant continuum. Physicochemical properties explained some of the microbial beta diversity spatiotemporal variation observed, with leaf phosphorus (P) and soil available potassium (AK) likely being the main factors that drove the geographical variation. We further identified the variation of edaphic (e.g., AK) and leaf physicochemical factors (e.g., P) were mainly caused by regional sites ( P < 0.05). Taken together, our study provides an empirical evidence that the distinct spatiotemporal patterns of alpha and beta diversity of rubber tree fungal diversity and significantly expand our understanding of ecological drivers of plant-associated microbial communities., Importance: Plants harbor diverse microorganisms in both belowground and aboveground compartments, which play a vital role in plant nitrogen supply and growth promotion. Understanding the spatiotemporal patterns of microbial communities is a prerequisite for harnessing them to promote plant growth. In this study, we show that the alpha and beta diversity of soil-plant continuum in rubber tree exhibited distinct spatiotemporal pattern. Alpha diversity is highly dependent on seasonal changes, while beta diversity only showed a geographical variation pattern. Climatic factors were the most important factors in shaping fungal alpha diversity. Leaf phosphorus (P) and soil available potassium (AK) were major drivers to induce geographical variation.

Garnet-type Li 6.25 Ga 0.25 La 3 Zr 2 O 12 (LGLZO) is believed to be a promising solid electrolyte for solid-state batteries due to its high ionic conductivity, safety, and good stability toward Li. However, one of the most challenges in practical application of LGLZO is the poor contact between Li and LGLZO. Herein, a ZnO layer is prepared on the surface of LGLZO pellet by ultrasonic spraying. Then, a Li 2 O/LiZn mixed ionic and electron conductive (MIEC) layer is formed at the Li/LGLZO interface via the conversion reaction between ZnO and molten Li. Experiments and theoretical calculations reveal that this MIEC layer can simultaneously improve interface contact, optimize interfacial kinetics, and guide homogeneous Li deposition. As a result, the interface impedance decreases significantly to 36 Ω cm 2 , the critical current density (CCD) can reach as high as 2.15 mA cm -2 , and the Li/ZnO@LGLZO/LiFePO 4 all-solid-state cells stably cycle 100 times at 0.5 C. This simple and effective approach may provide a viable strategy for improving the cycle performance of solid lithium metal batteries.

Background: Hepatocellular carcinoma (HCC) remains one of the most common human cancers, the death cases induced by HCC are increasing these years. Endoplasmic reticulum stress (ERS) occurs when misfolded proteins cannot be disposed of properly. It is reported that ERS plays a crucial role in the pathogenesis of human malignant tumors. The aim of this study is to construct a novel gene signature based on ERS for predicting prognosis in HCC., Methods: The data of HCC patients were downloaded from public databases. The Cox regression analysis and least absolute shrinkage and selection operator (LASSO) regression analysis were performed to construct ERS-related gene signature. The cases were divided into high- and low-risk groups based on the ERS-related gene signature in The Cancer Genome Atlas (TCGA) cohort. Subsequently, the differences in messenger ribonucleic acid (mRNA) expression patterns, immune status, tumor mutation burden (TMB) and copy number variants (CNV) were investigated between high- and low-risk groups. Then, a predictive nomogram according to the ERS-related gene signature and clinicopathological variables was established. At last, we explored the biological functions of TMX1 which had the biggest coefficient and we investigated the effect of BRSK2 on apoptosis in HCC., Results: In our study, a 9-gene ERS-related gene signature was constructed. The results showed that patients in the low-risk group had a better prognosis than the high-risk group patients. The results of receiver operating characteristic (ROC) curves revealed that the area under the curve (AUC) was 0.784 at 1 year, 0.780 at 2 years, 0.793 at 3 years in the training set. While in validation cohort, this index was 0.694 at 1 year, 0.622 at 2 years, 0.613 at 3 years respectively. The analysis of immune status revealed an immunosuppressive microenvironment in the high-risk group. The analysis of TMB and CNV revealed that the high-risk group patients had a higher genomic mutation frequency. In Univariate Cox regression analysis, the hazard ratio of RiskScore was 2.718 [95% confidence interval (CI): 2.173-3.399]. In Multivariate Cox regression analysis, the hazard ratio of RiskScore was 2.422 (95% CI: 1.805-3.25). Then, we established a nomogram according to the RiskScore and Eastern Cooperative Oncology Group performance status. The AUCs of the nomogram were 0.851 at 1 year, 0.860 at 2 years, and 0.866 at 3 years. At last, we found that TMX1 knockdown can inhibit the proliferation and migration of Huh7 and HepG2 cells. In addition, BRSK2 knockdown could promote the apoptosis induced by ERS., Conclusions: In our study, a novel ERS-related gene signature was constructed to predict the prognosis of HCC patients. In addition, TMX1 and BRSK2 could promote the progression of HCC. This study may provide a new understanding for HCC., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://tcr.amegroups.com/article/view/10.21037/tcr-24-191/coif). The authors have no conflicts of interest to declare., (2024 AME Publishing Company. All rights reserved.)

Catechol, which has a high toxicity and low degradability, poses significant risks to both human health and the environment. Tracking of catechol residues is essential to protect human health and to assess the safety of the environment. We constructed sensing platforms to detect catechol based on the conductive metal-organic frameworks [Ni 3 (HITP) 2 ] and their nanosilver composites. The reduction process of catechol at the Ni 3 (HITP) 2 /AgNP electrode is chemically irreversible as a result of the difference in compatibility of the oxidation stability and conductivity between the Ni 3 (HITP) 2 /AgNS and Ni 3 (HITP) 2 /AgNP electrodes. The electrochemical results show that the Ni 3 (HITP) 2 /AgNS electrode presents a lower detection limit of 0.053 μM and better sensitivity, reproducibility and repeatability than the Ni 3 (HITP) 2 /AgNP electrode. The kinetic mechanism of the catechol electrooxidation at the surface of the electrode is controlled by diffusion through a 2H + /2e - process. The transfer coefficient is the key factor used to illustrate this process. During the electrochemical conversion of phenol to ketone, more than half of Δ G is used to change the activation energy. We also studied the stability, anti-interference and reproducibility of these electrode systems.

Hollow MoS 2 cubes and spheres were synthesized by a one-step hydrothermal method with the hard template method. The structure and morphology were characterized, and their electrochemical properties were studied. It is concluded that the specific capacitance of the hollow MoS 2 cubes (335.7 F g -1 ) is higher than that of the hollow MoS 2 spheres (256.1 F g -1 ). The symmetrical supercapacitors were assembled, and the results indicate that the specific capacitance of the device composed of hollow MoS 2 spheres (32.9 F g -1 ) is slightly lower than that of the hollow MoS 2 cube (37.4 F g -1 ) device. Furthermore, the symmetrical supercapacitor (MoS 2 -cube//MoS 2 -cube) provides a maximum energy density of 4.93 W h kg -1 , which is greater than that of the symmetrical capacitor (MoS 2 -sphere//MoS 2 -sphere, 3.65 W h kg -1 ). This may indicate that hollow molybdenum disulfide cubes with substructures have more efficient charge transfer capabilities and better capacitance characteristics than hollow spheres. After 8000 cycles, the coulombic efficiency of the two symmetrical capacitors is close to 100%. The capacity retention of the MoS 2 sphere device (95.2%) is slightly higher than that of the MoS 2 cube device (90.1%). These results show that the pore structure, specific surface, and active site of MoS 2 with different hollow structures have a greater impact on its electrochemical properties.

Many recent efforts on the electrode design for advanced Li-ion batteries (LIBs) are often devoted to increasing the gravimetric capacity, but little attention is paid to the volumetric capacity which is more critical for practical application. Though the alloying-type anode materials are quite attractive, the challenge is that they must be composited with a large amount of carbon materials (e.g., GO, rGO, CNT) to buffer their large volume change, which would undoubtedly sacrifice the volumetric energy density of the whole electrode due to the carbon's low tap density (∼0.05 g/cm 3 ). Herein, we propose the unique layered Sb 2 Te 3 , which possesses high conductivity and a large volumetric capacity (3419 mAh/cm 3 ), to be served as the alternative anode for LIBs. Furthermore, we introduce natural graphite, which is low price and with high density (2.25 g/cm 3 ), into Sb 2 Te 3 to successfully build a novel Sb 2 Te 3 @Gra composite in which the Sb 2 Te 3 particles are wrapped by graphite layers. Interestingly, this modified Sb 2 Te 3 @Gra exhibits much more superior cycle stability (570 mAh/g after 200 cycles, 96% retention) than pure Sb 2 Te 3 (130 mAh/g after 200 cycles, 22% retention), while keeping its original large volumetric capacity output (∼3200 mAh/cm 3 ) at the same time. More specially, it enables a reversible structure recovery of Sb 2 Te 3 , guaranteeing the electrode integrity and cyclability. These extraordinary phenomena are investigated in detail, whose results display that the outer graphite layer plays an important role by facilitating the intimate contact with Sb 2 Te 3 particles and protecting them from pulverization. Besides, such graphite layer greatly promotes the electron-transfer during lithiation, helping to improve the rate capability (372 mAh/g at 2000 mA/g, 60% retention). Consequently, the assembled Sb 2 Te 3 //LiCoO 2 full cell delivers a large capacity of 500 mAh/g, with stable discharge plateau and cycle stability, revealing its high potential for practical application.

Many research efforts for advanced Li-ion batteries have been made to design new material with large capacity and long cycle life, but little attention has been paid to regulate the voltage platform until now. Although quite attractive for the binary Ge-based chalcogenides, challenge is that a large potential gap as well as incongruous reaction kinetics is typically found between their conversion step (>1.6 V) and alloying region (<0.4 V). Herein, we propose an endogenetic structural design by grafting Sb 2 Te 3 building block into layered GeTe to establish a ternary Ge 2 Sb 2 Te 5 compound, which can effectively level such a big potential gap. Turning from semiconductive GeTe into metallic conductive Ge 2 Sb 2 Te 5 , the reaction kinetics can be enhanced. The Li x Te formation step in Ge 2 Sb 2 Te 5 is found declined to 1.30 V, and the enlistment of Sb (∼0.78 V) bridges the conversion and alloying plateau; thus, the incongruous reaction kinetics and large potential gap between the conversion-alloying step can be alleviated. Furthermore, there is a spatially confined and synergistic effect among Te, Sb, and Ge components, conducting the Li x Te and Li x Ge processes in a more harmonious and gentle way. Therefore, Ge 2 Sb 2 Te 5 exhibites much enhanced cyclability and rate performance, with 546 mAh/g remained at 2000 mA/g. This unique design strategy can be leveraged to manipulate the voltage profile of other compounds.

TiO 2 is an excellent photocatalytic and photovoltaic material but suffers low efficiency because of deep trap states giving rise to fast charge and energy losses. Using a combination of time-domain density functional theory and nonadiabatic molecular dynamics, we demonstrate that grain boundaries (GBs), which are common in polycrystalline TiO 2 , accelerate nonradiative electron-hole recombination by a factor of 3. Despite GBs increase the band gap without creating deep trap states, and accelerate coherence loss, they enhance nonadiabatic electron-phonon coupling, and facilitate the relaxation. Importantly, electrons accumulated at the boundaries together with the relatively long-lived excite state favor photocatalytic reaction. Our study rationalizes the experimental observations and provides valuable perspectives for improving the device performance by defect engineering.

Compared with elemental phosphorus, GeP 5 , with much better thermostability and super higher conductivity, can exhibit a comparable capacity (>2000 mA h g -1 ) with a much higher first Coulombic efficiency (95%) for lithium-ion batteries. However, such high capacity is accompanied by large volume expansions, leading to fast capacity fading. To improve the cycle stability, fabricating a special nanostructure to reduce the volume stress and compositing with a carbon matrix to buffer the volume change are highly required. However, nanostructured metal phosphides were rarely reported up to now because they are difficult to be synthesized via a normal wet chemistry method or gas phosphorization because of lack of proper reactants and poor thermostability of phosphides. Herein, we successfully achieve uniform carbon-encapsulated GeP 5 nanofibers (GeP 5 @C-NF) by processing GeP 5 nanoparticles into carbon nanofibers via electrospinning. After carbon encapsulation, the thermostability of GeP 5 can be greatly improved to over 600 °C for higher battery safety. Such a nanofiber structure in which nanosized GeP 5 is embedded in a carbon matrix can greatly accommodate the large volume changes during lithiation and provide fast electron transportation, thus contributing to a long cycle life (>1000 mA h g -1 after 200 cycles) and high rate performance (803 mA h g -1 at 2000 mA g -1 ). This morphology processing technique can be easily extended to other metal phosphide anodes which are limited by a lack of appropriate synthesis methods and poor thermostability.

GeP 5 is a recently reported new anode material for lithium ion batteries (LIBs), it holds a large theoretical capacity about 2300 mAh g -1 , and a high rate capability due to its bi-active components and superior conductivity. However, it undergoes a large volume change during its electrochemical alloying and de-alloying with Li, a suitable binder is necessary to stable the electrode integrity for improving cycle performance. In this work, we tried to apply aqueous binders LiPAA and NaCMC to GeP 5 anode, and compared the difference in electrochemical performance between them and traditional binder PVDF. As can be seen from the test result, GeP 5 can keep stable in both common organic solvents and proton solvents such as water and alcohol solvents, it meets the application requirements of aqueous binders. The electrochemistry results show that the use of LiPAA binder can significantly improve the initial Coulombic efficiency, reversible capacity, and cyclability of GeP 5 anode as compared to the electrodes based on NaCMC and PVDF binders. The enhanced electrochemical performance of GeP 5 electrode with LiPAA binder can be ascribed to the unique high strength long chain polymer structure of LiPAA, which also provide numerous uniform distributed carboxyl groups to form strong ester groups with active materials and copper current collector. Benefit from that, the GeP 5 electrode with LiPAA can also exhibit excellent rate capability, and even at low temperature, it still shows attractive electrochemical performance.

Layered TiS 3 materials hold appealing potential in photovoltaics and optoelectronics due to their excellent electronic and optical properties. Using time domain density functional theory combined with nonadiabatic (NA) molecular dynamics, we show that the electron-hole recombination in pristine TiS 3 nanoribbons (NRs) occurs in tens of picoseconds and is over 10-fold faster than the experimental value. By performing an atomistic ab initio simulation with a sulfur vacancy, we demonstrate that a sulfur vacancy greatly reduces electron-hole recombination, achieving good agreement with experiment. Introduction of a sulfur vacancy increases the band gap slightly because the NR's highest occupied molecular orbital is lowered in energy. More importantly, the sulfur vacancy partially diminishes the electron and hole wave functions' overlap and reduces NA electron-phonon coupling, which competes successfully with the longer decoherence time, slowing down recombination. Our study suggests that a rational choice of defects can control nonradiative electron-hole recombination in TiS 3 NRs and provides mechanistic principles for photovoltaic and optoelectronic device design.

The low electronic conductivity and the sluggish sodium-ion diffusion in the compact crystal structure of Ti-based anodes seriously restrict their development in sodium-ion batteries. In this study, a new hollandite K x TiO 2 with large (2 × 2) tunnels is synthesized by a facile carbothermal reduction method, and its sodium storage performance is investigated. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses illustrate the formation mechanism of the hollandite K x TiO 2 upon the carbothermal reduction process. Compared to the traditional layered or small (1 × 1) tunnel-type Ti-based materials, the hollandite K x TiO 2 with large (2 × 2) tunnels may accommodate more sodium ions and facilitate the Na + diffusion in the structure; thus, it is expected to get a large capacity and realize high rate capability. The synthesized K x TiO 2 with large (2 × 2) tunnels shows a stable reversible capacity of 131 mAh g -1 (nearly 3 times of (1 × 1) tunnel-structured Na 2 Ti 6 O 13 ) and superior cycling stability with no obvious capacity decay even after 1000 cycles, which is significantly better than the traditional layered Na 2 Ti 3 O 7 (only 40% of capacity retention in 20 cycles). Moreover, the carbothermal process can naturally introduce oxygen vacancy and low-valent titanium as well as the surface carbon coating layer to the structure, which would greatly enhance the electronic conductivity of K x TiO 2 and thus endow this material high rate capability. With a good rate capability and long cyclability, this hollandite K x TiO 2 can serve as a new promising anode material for room-temperature long-life sodium-ion batteries for large-scale energy storage systems, and the carbothermal reduction method is believed to be an effective and facile way to develop novel Ti-based anodes with simultaneous carbon coating and Ti(III) self-doping.

(-)-Epigallocatechin-3-gallate (EGCG) from green tea has anti-cancer effect. The cytotoxic actions of EGCG are associated with its auto-oxidation, leading to the production of hydrogen peroxide and formation of numerous EGCG auto-oxidation products (EAOPs), the structures and bioactivities of them remain largely unclear. In the present study, we compared several fundamental properties of EGCG and EAOPs, which were prepared using 5mg/mL EGCG dissolved in 200mM phosphate buffered saline (pH 8.0 at 37°C) and normal oxygen partial pressure for different periods of time. Despite the complete disappearance of EGCG after the 4-h auto-oxidation, 4-h EAOPs gained an enhanced capacity to deplete cysteine thiol groups, and retained the cytotoxic effects of EGCG as well as the capacity to produce hydrogen peroxide and inhibit thioredoxin reductase, a putative target for cancer prevention and treatment. The results indicate that certain EAOPs possess equivalent cytotoxic activities to EGCG, while exhibiting simultaneously enhanced capacity for cysteine depletion. These results imply that EGCG and EAOPs formed extracellularly function in concert to exhibit cytotoxic effects, which previously have been ascribed to EGCG alone., (Copyright © 2016 Elsevier Ltd. All rights reserved.)