China West Normal University

Iron is the cheapest and one of the most abundant transition metals. Natural [FeFe]-hydrogenases exhibit remarkably high activity in hydrogen evolution, but they suffer from high oxygen sensitivity and difficulty in scale-up. Herein, an FeP nanowire array was developed on Ti plate (FeP NA/Ti) from its β-FeOOH NA/Ti precursor through a low-temperature phosphidation reaction. When applied as self-supported 3D hydrogen evolution cathode, the FeP NA/Ti electrode shows exceptionally high catalytic activity and good durability, and it only requires overpotentials of 55 and 127 mV to afford current densities of 10 and 100 mA cm(2) , respectively. The excellent electrocatalytic performance is promising for applications as non-noble-metal HER catalyst with a high performance-price ratio in electrochemical water splitting for large-scale hydrogen fuel production.

It is highly desirable but challenging to develop bifunctional catalysts for efficiently catalyzing both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in energy storage and conversion systems. Here a simple yet cost-effective strategy is developed to fabricate nitrogen and phosphorus dual-doped graphene/carbon nanosheets (N,P-GCNS) with N,P-doped carbon sandwiching few-layers-thick graphene. The as-prepared N,P-GCNS shows outstanding catalytic activity toward both ORR and OER with a potential gap of 0.71 V between the OER potential at a current density of 10 mA cm–2 and the ORR potential at a current density of −3 mA cm–2, illustrating that it is the best metal-free bifunctional electrocatalysts reported to date. The superb bifunctional catalytic performance is attributed to the synergistic effects between the doped N and P atoms, the full exposure of the active sites on the surface of the N,P-GCNS nanosheets, the high conductivity of the incorporated graphene, and the large surface area and hierarchical pores for sufficient contact and rapid transportation of the reactants.

We describe the current plans for a spectroscopic survey of millions of stars in the Milky Way galaxy using the Guo Shou Jing Telescope (GSJT, formerly called the Large sky Area Multi-Object fiber Spectroscopic Telescope — LAMOST). The survey will obtain spectra for 2.5 million stars brighter than r < 19 during dark/grey time, and 5 million stars brighter than r < 17 or J < 16 on nights that are moonlit or have low transparency. The survey will begin in the fall of 2012, and will run for at least four years. The telescope's design constrains the optimal declination range for observations to 10° < δ < 50°, and site conditions lead to an emphasis on stars in the direction of the Galactic anticenter. The survey is divided into three parts with different target selection strategies: disk, anticenter, and spheroid. The resulting dataset will be used to study the merger history of the Milky Way, the substructure and evolution of the disks, the nature of the first generation of stars through identification of the lowest metallicity stars, and star formation through study of open clusters and OB associations. Detailed design of the LAMOST Experiment for Galactic Understanding and Exploration (LEGUE) survey will be completed in summer 2012, after a review of the results of the pilot survey.

This review summarizes the recent research progress made in nanostructured metal nitrides for electrochemical and photo(electro)chemical water splitting.

A simple, economical, and green method for the preparation of water-soluble, high-fluorescent carbon quantum dots (C-dots) has been developed via hydrothermal process using aloe as a carbon source. The synthesized C-dots were characterized by atomic force microscope (AFM), transmission electron microscopy (TEM), fluorescence spectrophotometer, UV-vis absorption spectra as well as Fourier transform infrared spectroscopy (FTIR). The results reveal that the as-prepared C-dots were spherical shape with an average diameter of 5 nm and emit bright yellow photoluminescence (PL) with a quantum yield of approximately 10.37%. The surface of the C-dots was rich in hydroxyl groups and presented various merits including high fluorescent quantum yield, excellent photostability, low toxicity and satisfactory solubility. Additionally, we found that one of the widely used synthetic food colorants, tartrazine, could result in a strong fluorescence quenching of the C-dots through a static quenching process. The decrease of fluorescence intensity made it possible to determine tartrazine in the linear range extending from 0.25 to 32.50 μM, This observation was further successfully applied for the determination of tartrazine in food samples collected from local markets, suggesting its great potential toward food routine analysis. Results from our study may shed light on the production of fluorescent and biocompatible nanocarbons due to our simple and environmental benign strategy to synthesize C-dots in which aloe was used as a carbon source.

Abstract Titanium‐based catalysts are needed to achieve electrocatalytic N 2 reduction to NH 3 with a large NH 3 yield and a high Faradaic efficiency (FE). One of the cheapest and most abundant metals on earth, iron, is an effective dopant for greatly improving the nitrogen reduction reaction (NRR) performance of TiO 2 nanoparticles in ambient N 2 ‐to‐NH 3 conversion. In 0.5 m LiClO 4 , Fe‐doped TiO 2 catalyst attains a high FE of 25.6 % and a large NH 3 yield of 25.47 μg h −1 mg cat −1 at −0.40 V versus a reversible hydrogen electrode. This performance compares favorably to those of all previously reported titanium‐ and iron‐based NRR electrocatalysts in aqueous media. The catalytic mechanism is further probed with theoretical calculations.

Developing non-noble-metal hydrogen evolution reaction electrocatalysts with high activity is critical for future renewable energy systems. The direct growth of active phases on current collectors not only eliminates using polymer binder but also offers time-saving preparation of electrode. In this Letter, we develop self-supported FeP nanorod arrays on carbon cloth (FeP NAs/CC) via low-temperature phosphidation of its Fe2O3 NAs/CC. As a novel 3D hydrogen evolution cathode in acidic media, the FeP NAs/CC exhibits high catalytic activity and only needs an overpotential of 58 mV to afford current density of 10 mA/cm2. This electrode also works efficiently in both neutral and alkaline solutions.

Metal-free phosphorus-doped graphene nanosheets (P-TRG) with large surface area (496.67 m2 g−1) and relatively high P-doping level (1.16 at.%) were successfully prepared by thermal annealing a homogenous mixture of graphene oxide and 1-butyl-3-methlyimidazolium hexafluorophosphate under argon atmosphere. It was found that the P atoms were substitutionally incorporated into the carbon framework and were partially oxidized, which created new active sites for the oxygen reduction reaction (ORR). Accordingly, the ORR catalytic performance of the P-doped graphene was demonstrated to be better than or at least comparable to that of the benchmark Pt/C catalyst.

Showing MOFs' true colors: An iron-based metal–organic framework, MIL-53(Fe), is explored as an enzyme mimic with intrinsic peroxidase-like activity. MIL-53(Fe) can catalyze the oxidation of different peroxidase substrates in the presence of H2O2 (see graphic; TMB=3,3′,5,5′-tetramethylbenzidine, OPD=o-phenylenediamine), providing a new and simple colorimetric detection of hydrogen peroxide and ascorbic acid. Owing to both the enhanced instrumental transduction and the potential for direct visual readout, colorimetric biosensing has drawn intense attention in biological science and analytical chemistry. It offers the advantages of simplicity, rapidity, and cheapness as well as the fact that there is no requirement for any sophisticated instrumentation. As a basis for this technique, colorimetric sensors that signal analyte interaction through a change in color are undoubtedly crucial for its successful implementation. To this end, biosensors based on enzyme-mimetic inorganic materials have emerged as a new class of ideal and important colorimetric detection tools for biosensing, owing to their high stability, easy preparation, controllable structure and composition, and tunable catalytic activity.1 So far, a number of inorganic materials with peroxidase-like activity, including oxides,2 metals,3 sulfides,4 carbon,5 and polyoxometalates6 have been successfully exploited. Metal–organic frameworks (MOFs) are an intriguing class of porous crystalline inorganic–organic hybrid materials built from metal ions and polyfunctional organic ligands and have attracted increasing attention in recent years, owing to both fundamental scientific interest and attractive applications.7 Particularly, the fascinating features, which include structural diversity, flexibility and alterability, intrinsic porosity, and desired chemical functionality, endow them with great promise in a variety of fields such as gas storage, separation, drug delivery, bioimaging, and catalysis.8 Very recently, great effort has been made to provide new insights into the application of MOFs in sensing.9 Herein, we report that MIL-53 iron(III) terephthalate (MIL-53(Fe)), a typical iron-based metal–organic framework (MOF) with formula Fe(OH)(O2CC6H4CO2)⋅H2O (Scheme S1 in the Supporting Information), possesses intrinsic peroxidase-like activity, catalyzing the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB), o-phenylenediamine (OPD), and 1,2,3-trihydroxybenzene (THB) in the presence of H2O2. MIL-53(Fe) as a peroxidase mimic provided a colorimetric assay for H2O2 (Scheme 1A). Moreover, an inhibition effect was induced by ascorbic acid (AA) on the oxidation of OPD catalyzed by MIL-53(Fe) in the presence of H2O2, leading to a simple colorimetric method for the detection of AA (Scheme 1B). Schematic illustration of colorimetric detection of A) H2O2 and B) AA by using MIL-53(Fe) as a peroxidase mimetic. Metal–organic framework MIL-53(Fe) was prepared by a facile one-pot solvothermal method using DMF as solvent. The structure and morphology of MIL-53(Fe) were identified by powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy and UV/Vis absorption spectroscopy. The PXRD pattern of MIL-53(Fe) (Figure 1 A) shows that the as-obtained sample was crystalline, and the diffraction peaks were coincident with the previously reported MOF MIL-53 as well as the simulated one.10 The SEM image (Figure 1 B) shows that MIL-53(Fe) mainly consists of pseudo sphere-like aggregates with a size of 200–800 nm. The chemical composition determined by the EDX spectrum (Figure S1 in the Supporting Information) reveals that the C, Fe, and O elements coexist in MIL-53(Fe). The EDX elemental mapping (Figure S2 in the Supporting Information) further confirmed these elements were uniformly distributed in MIL-53(Fe). FTIR spectroscopy (Figure 1 C) shows the characteristic vibration bands of the framework OCO groups, reflecting the presence of the dicarboxylate linker in MIL-53(Fe). The diffuse reflectance UV/Vis spectrum of MIL-53(Fe) (Figure 1 D) shows a strong optical absorption band at 220–350 nm, attributed to ligand-to-metal charge transfer (LMCT).11 The weight losses (Figure S3 in the Supporting Information) of MIL-53(Fe), as determined by thermogravimetric analysis (TGA), are well within the expected range. A) PXRD patterns of a) the simulated MIL-53(Fe) created from CIF in ref. 10a, b) MIL-53(Fe) before the catalytic reaction, and c) MIL-53(Fe) after the catalytic reaction. B) SEM image of MIL-53(Fe). C) FTIR spectrum of MIL-53(Fe). D) UV/Vis diffuse reflectance spectrum of the as-prepared MIL-53(Fe). The peroxidase-like activity of MIL-53(Fe) was evaluated by the catalytic oxidation of peroxidase substrate TMB in the presence of H2O2. As shown in Figure 2 a and b, in the absence and presence of H2O2, a colorless TMB solution was observed, which displayed a negligible absorption in the range 350 to 800 nm, indicating that no oxidation reaction occurred in the absence of MIL-53(Fe). In contrast, MIL-53(Fe) was highly active in catalyzing the oxidation of TMB substrate by H2O2. The addition of MIL-53(Fe) produced a typical deep-blue color in the reaction mixture, and the solutions exhibited intense characteristic absorbance at 369 and 652 nm (Figure 2 c), bands that are ascribed to the charge-transfer complexes derived from the one-electron oxidation of TMB,12 similar to the phenomena observed for the commonly used horse radish peroxidase (HRP) enzyme.13 As Fe3+ ions are Fenton-like reagents, they could also catalyze TMB oxidation in the presence of H2O2 (Figure S4 in the Supporting Information).14 The concentration of iron ions in the supernatant of MIL-53(Fe) solution was detected by using the colorimetric method.1b, 15 In the pH range of 2.0–6.0, the absorbance at 508 nm for the supernatants of the MIL-53(Fe) solution can be ignored as it indicates that the iron ions scarcely leached from MIL-53(Fe).1b Furthermore, the phase structure of MIL-53(Fe) after the peroxidase reaction remained unchanged (Figure 1A-a and Figures S5 and S6 in the Supporting Information). All these observations indicate that MIL-53(Fe) possesses peroxidase-like activity for oxidation of TMB in the presence of H2O2. Moreover, the peroxidase-like activity of MIL-53(Fe) was confirmed by catalytic oxidation of other peroxidase substrates such as OPD16a–16c and THB9h, 16c in the presence of H2O2; these reactions could also produce the typical color changes (Figure S7 in the Supporting Information). UV/Vis spectra of a) the TMB solution, b) TMB and H2O2, c) TMB, H2O2, and MIL-53(Fe), d) MIL-53(Fe) suspension in a pH 4.0 acetate buffer at 40 °C for 30 min. [TMB]: 0.19 mM, [H2O2]: 38 mM, [MIL-53(Fe)]: 0.038 mg mL−1. Inset shows corresponding photographs. The peroxidase-like catalytic activity of MIL-53(Fe) was, therefore, further investigated by selecting the substrates TMB and H2O2 as a model reaction system. The peroxidase-like activity of MIL-53(Fe) was measured while varying the pH from 2.0 to 10.0, the temperature from 10 °C to 60 °C, the H2O2 concentration from 0.95 μM to 545 mM, and the catalyst concentration from 0.1 to 4 mg mL−1(Figures S8–11 in the Supporting Information). The catalytic activity of MIL-53(Fe) was found to be closely dependent on pH, temperature, H2O2 concentration, and catalyst concentration. The optimal conditions are approximately pH 4.0, 40 °C, and 480 μM H2O2, conditions similar to those previously reported for nanostructure-based peroxidase mimetics and HRP.14a, 17 The steady-state kinetic assays were carried out by changing the concentration of TMB and H2O2 in this catalytic system, the results of which indicate that the reaction catalyzed by MIL-53(Fe) obeys the typical Michaelis–Menten mechanism (Figure S12 in the Supporting Information).13 The kinetic parameters, such as the Michaelis–Menten constant (KM) and maximum initial velocity (Vmax), were obtained from a Lineweaver–Burk plot.13 The KM value of MIL-53(Fe) with H2O2 as the substrate was much lower than those of HRP and other nanomaterials-based peroxidase mimics (Tables S1 and S2 in the Supporting Information), suggesting that MIL-53(Fe) has a much higher affinity to H2O2 than HRP and other mimics. The catalytic mechanism of MIL-53(Fe) was further investigated by the detection of in situ-generated hydroxyl radicals (.OH) with a photoluminescence (PL) method.18 A gradual increase in PL intensity at about 425 nm was observed with increasing MIL-53(Fe) concentration (Figure S13 in the Supporting Information). Notably, there was no PL intensity in the absence of MIL-53(Fe). This solidly confirms that MIL-53(Fe) can catalytically activate H2O2 to produce .OH radicals, which could then react with TMB to produce a color change in the reaction.1b, 2c, 14b, 19 To further support this mechanism, the electrocatalytic activity of MIL-53(Fe)-modified glassy carbon electrodes (MIL-53(Fe)/GCE) towards the electrochemical reduction of H2O2 was studied by using their amperometric response. The reduction current increased sharply to a steady-state value for MIL-53(Fe)/GCE upon the addition of an aliquot of H2O2 (Figure S14 in the Supporting Information). The observable electrocatalytic activity could be attributed to the promotion of electron transfer between H2O2 (electron acceptor) and the electrode (electron donor). Based on the above, it is believed that the peroxidase-like activity of MIL-53(Fe) could originate from its catalytic activation of H2O2 through electron transfer to produce .OH radicals by a Fenton-like reaction.14, 19 Based on the aforementioned intrinsic peroxidase-like property of MIL-53(Fe), we developed a simple colorimetric method for the detection of H2O2 by using the MIL-53(Fe)-catalyzed colored reaction. Figure 3 shows the dependence of the absorbance at 652 nm on the concentration of H2O2 under optimal conditions (i.e., pH 4.0, 40 °C). The absorbance at 652 nm increases with increasing H2O2 concentration from 0.95 μM to 0.48 mM. A linear relationship (inset in Figure 3) between the absorbance and the H2O2 concentration between 0.95 and 19 μM (R2=0.990) was obtained, with a detection limit of 0.13 μM, which is lower than that provided by Fe3O4 nanoparticles.2b Furthermore, the color variation is obvious on visual observation (inset in Figure 3), offering a convenient approach to detect H2O2 by the naked eye even at low concentrations. A dose-response curve for H2O2 detection using MIL-53(Fe) under the optimum conditions described. Inset: linear calibration plot for H2O2 and corresponding photographs of the colored reaction mixtures for different concentrations of H2O2. In addition, we also observed that MIL-53(Fe) could catalyze the oxidation of the other peroxidase substrates, such as OPD, in the presence of H2O2, resulting in a yellow–orange solution (Figure S15 in the Supporting Information) and, interestingly, we find that with the addition of a trace amount of ascorbic acid (AA), the catalytic activity of MIL-53(Fe) was greatly suppressed, subsequently yielding a light yellow–orange solution (Figure S15 in the Supporting Information). Based on these observations, we therefore designed a colorimetric method for detection of AA with this MIL-53(Fe)-based sensing system. Figure 4 A shows a typical AA concentration-response curve, which indicates that the intensity of the absorption peak at 450 nm decreases with increasing AA concentration. The corresponding calibration plot is shown in Figure 4 B. The linear detection range is estimated to be 28.6 to 190.5 μM (R2=0.992). The detection limit is estimated to be 15 μM. A) UV/Vis spectra of OPD oxidation catalyzed by MIL-53(Fe) in the presence of inhibitor AA in a pH 4.0 acetate buffer at 25 °C for 15 min ([OPD]: 2.4 mM, [H2O2]: 0.24 M, [MIL-53(Fe)]: 0.038 mg mL−1). B) Linear relationship between change in absorbance at 450 nm and concentration of AA. ΔA=A0−Ai (A0 and Ai are the absorbance at 450 nm before and after addition of AA with a concentration of i, respectively). In summary, we have demonstrated that MIL-53(Fe) possesses highly efficient intrinsic peroxidase-like activity, catalyzing the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) and o-phenylenediamine (OPD) in the presence of H2O2. MIL-53(Fe) as a peroxidase mimic provided a colorimetric assay for H2O2. Furthermore, the inhibition effect of ascorbic acid (AA) on the oxidation of OPD catalyzed by MIL-53(Fe) in the presence of H2O2 was investigated. Based on the AA-induced inhibition of the peroxidase-like activity of MIL-53(Fe), a simple colorimetric method for the detection of AA was realized. We believed that the present work could open up the possibility of utilizing MOFs as enzymatic mimics in immunoassays and biotechnology. This work was supported by National Natural Science Foundation of China (Grant No. 21103141, 21207108), Sichuan Youth Science and Technology Foundation (Grant No. 2013 JQ0012), the Applied Basic Research Program of Sichuan Provincial Science and Technology Department (Grant No. 2011 JYZ019) and the Research Foundation of CWNU (Grant No. 12B018). As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

MXene-derived TiO₂@C/g-C₃N₄ heterojunctions exhibit superior performance for photocatalytic nitrogen reduction to ammonia under visible light irradiation.

The present communication reports the topotactic conversion of NiCo2O4 nanowires array on carbon cloth (NiCo2O4 NA/CC) into NiCo2S4 NA/CC, which is used as an efficient bifunctional electrocatalyst for water splitting with good durability and superior activity in 1.0 M KOH. This NiCo2S4 NA/CC electrode produces 100 mA cm(-2) at an overpotential of 305 mV for hydrogen evolution and 100 mA cm(-2) at an overpotential of 340 mV for oxygen evolution. To afford a 10 mA cm(-2) water-splitting current, the alkaline water electrolyzer made from NiCo2S4 NA/CC needs a cell voltage of 1.68 V, which is 300 mV less than that for NiCo2O4 NA/CC, and has good stability.

In this communication, we report that a Co-doped NiSe2 nanoparticles film electrodeposited on a conductive Ti plate (Co0.13Ni0.87Se2/Ti) behaves as a robust electrocatalyst for both HER and OER in strongly basic media, with good activity over a NiSe2/Ti counterpart. This Co0.13Ni0.87Se2/Ti catalytic electrode delivers 10 mA cm(-2) at an overpotential of 64 mV for HER and 100 mA cm(-2) at an overpotential of 320 mV for OER in 1.0 M KOH. A voltage of only 1.62 V is required to drive 10 mA cm(-2) for the two-electrode alkaline water electrolyzer using Co0.13Ni0.87Se2/Ti as an anode and cathode.

Abstract It is highly attractive, but still remains a huge challenge, to develop efficient non‐noble‐metal electrocatalysts for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) under neutral and alkaline conditions. In this paper, we report that CoP nanosheet arrays on carbon cloth (CoP NA/CC), derived from α‐Co(OH) 2 NA/CC, behaves as a three‐dimensional bifunctional water‐splitting catalyst electrode with high activity and durability in neutral and alkaline media. Such CoP NA/CC demands overpotentials of 145 and 52 mV to afford 10 mA cm −2 for the HER in 1.0 M phosphate buffer solution (PBS) and 1.0 M KOH, respectively, with much superior activity to α‐Co(OH) 2 NA/CC. It can be attributed to the more thermo‐neutral hydrogen adsorption free energy for CoP than α‐Co(OH) 2 , according to density functional theory calculations. This electrode also demonstrates superior OER activity over α‐Co(OH) 2 NA/CC and needs overpotentials of only 536 and 300 mV to drive 10 mA cm −2 at neutral and alkaline pH, respectively. The two‐electrode water electrolyzer using CoP NA/CC as both the cathode and anode shows a 2 mA cm −2 water‐splitting current at a cell voltage of 1.60 V in 1.0 M PBS and needs 1.65 V for 10 mA cm −2 under alkaline condition with excellent stability.

An amorphous CoSe film electrodeposited on a Ti mesh (a-CoSe/Ti) acts as an efficient water-splitting catalyst in strongly basic media, with the need for overpotentials of 292 and 121 mV to drive 10 mA cm⁻² for OER and HER, respectively.

A Zn-doped Ni₃S₂nanosheet array on Ni foam (Zn-Ni₃S₂/NF) acts as a high-performance and durable electrocatalyst for the oxygen evolution reaction in 1.0 M KOH, driving a catalytic current density of 100 mA cm⁻²at an overpotential of 330 mV, 90 mV less than that for Ni₃S₂/NF.

on the surface of SS mesh may be the active species for OER. The abundant and commercial availability, long-term stability and low-cost property of nickel foam and stainless steel mesh enable their large-scale practical application in water splitting.

OBJECTIVES: Tanshinone I (Tan-I) is one of the vital fatsoluble monomer components, which extracted from Chinese medicinal herb Salvia miltiorrhiza Bunge. It has been shown that Tan-I exhibited anti-tumour activities on different types of cancers. However, the underlying mechanisms by which Tan-Ⅰ regulates apoptosis and autophagy in ovarian cancer remain unclear. Thus, this study aimed to access the therapy effect of Tan-Ⅰ and the underlying mechanisms. METHODS: Ovarian cancer cells A2780 and ID-8 were treated with different concentrations of Tan-Ⅰ (0, 1.2, 2.4, 4.8 and 9.6 μg/mL) for 24 hours. The cell proliferation was analysed by CCK8 assay, EdU staining and clone formation assay. Apoptosis was assessed by the TUNEL assay and flow cytometry. The protein levels of apoptosis protein (Caspase-3), autophagy protein (Beclin1, ATG7, p62 and LC3II/LC3I) and PI3K/AKT/mTOR pathway were determined by Western blot. Autophagic vacuoles in cells were observed with LC3 dyeing using confocal fluorescent microscopy. Anti-tumour activity of Tan-Ⅰ was accessed by subcutaneous xeno-transplanted tumour model of human ovarian cancer in nude mice. The Ki67, Caspase-3 level and apoptosis level were analysed by immunohistochemistry and TUNEL staining. RESULTS: Tan-Ⅰ inhibited the proliferation of ovarian cancer cells A2780 and ID-8 in a dose-dependent manner, based on CCK8 assay, EdU staining and clone formation assay. In additional, Tan-Ⅰ induced cancer cell apoptosis and autophagy in a dose-dependent manner in ovarian cancer cells by TUNEL assay, flow cytometry and Western blot. Tan-Ⅰ significantly inhibited tumour growth by inducing cell apoptosis and autophagy. Mechanistically, Tan-Ⅰ activated apoptosis-associated protein Caspase-3 cleavage to promote cell apoptosis and inhibited PI3K/AKT/mTOR pathway to induce autophagy. CONCLUSIONS: This is the first evidence that Tan-Ⅰ induced apoptosis and promoted autophagy via the inactivation of PI3K/AKT/mTOR pathway on ovarian cancer and further inhibited tumour growth, which might be considered as effective strategy.

Recent work, which treats the Hawking radiation as a semiclassical tunneling process at the horizon of the Schwarzschild and Reissner-Nordstr\"om spacetimes, indicates that the exact radiant spectrum is no longer pure thermal after considering the black hole background as dynamical and the conservation of energy. In this paper, we extend the method to investigate Hawking radiation as massless particles tunneling across the event horizon of the Kerr black hole and that of charged particles from the Kerr-Newman black hole by taking into account the energy conservation, the angular momentum conservation, and the electric charge conservation. Our results show that when self-gravitation is considered, the tunneling rate is related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum, but is consistent with an underlying unitary theory.

A synergetic architecture composed of nitrogen-doped carbon encapsulating cobalt and molybdenum carbide nanoparticles (Co_xMo_y@NC) presents excellent performance towards both HER and OER catalysis in alkaline medium.

The Haber–Bosch process for industrial NH3 production suffers from harsh reaction conditions and serious CO2 emission. Electrochemical N2 reduction offers a carbon-neutral alternative for more energy-saving NH3 synthesis but requires active electrocatalysts for the N2 reduction reaction (NRR). In this Letter, boron nanosheet (BNS) is proposed as an elemental two-dimensional (2D) material to effectively catalyze the NRR toward NH3 synthesis with excellent selectivity. When tested in 0.1 M Na2SO4, such BNS catalyst attains a high Faradaic efficiency of 4.04% and a large NH3 yield of 13.22 μg h–1 mgcat–1 at −0.80 V vs reversible hydrogen electrode, with strong electrochemical durability. Density functional theory calculations suggest that the B atoms of both oxidized and H-deactivated BNS can catalyze the NRR more effectively than clean BNS, and the rate-determining step is the desorption process of the second NH3 gas.