Boron-doped graphene with different boron structures was rationally synthesized to enhance the adsorption of N 2 , thus enabling an efficient metal-free electrocatalyst for electrochemical N 2 reduction in aqueous solution at ambient conditions. At a doping level of 6.2%, boron-doped graphene achieved a NH 3 production rate of 9.8 mg$hr À1 $cm À2 and an excellent faradic efficiency (10.8% at À0.5 V versus reversible hydrogen electrode).

The electrocatalytic reduction of CO2 into value-added chemicals such as hydrocarbons has the potential for supplying fuel energy and reducing environmental hazards, while the accurate tuning of electrocatalysts at the ultimate single-atomic level remains extremely challenging. In this work, we demonstrate an atomic design of multiple oxygen vacancy-bound, single-atomic Cu-substituted CeO2 to optimize the CO2 electrocatalytic reduction to CH4. We carried out theoretical calculations to predict that the single-atomic Cu substitution in CeO2(110) surface can stably enrich up to three oxygen vacancies around each Cu site, yielding a highly effective catalytic center for CO2 adsorption and activation. This theoretical prediction is consistent with our controlled synthesis of the Cu-doped, mesoporous CeO2 nanorods. Structural characterizations indicate that the low concentration (<5%) Cu species in CeO2 nanorods are highly dispersed at single-atomic level with an unconventionally low coordination number ∼5, suggesting the direct association of 3 oxygen vacancies with each Cu ion on surfaces. This multiple oxygen vacancy-bound, single atomic Cu-substituted CeO2 enables an excellent electrocatalytic selectivity in reducing CO2 to methane with a faradaic efficiency as high as 58%, suggesting strong capabilities of rational design of electrocatalyst active centers for boosting activity and selectivity.

BackgroundWith more than 600,000 mortalities each year, colorectal cancer (CRC) is the third most commonly diagnosed type of cancer worldwide. Recently, mechanisms involving noncoding RNAs have been implicated in the development of CRC.MethodsWe examined expression levels of lncRNA CRNDE and miR-181a-5p in 64 cases of CRC tissues and cell lines by qRT-PCR. Gain-of-function and loss-of-function assays were performed to examine the effect of CRNDE and miR-181a-5p on proliferation and chemoresistance of CRC cells. Using fluorescence reporter and western blot assays, we also explored the possible mechanisms of CRNDE in CRC cells.ResultsIn this study, we found that the expression levels of the CRNDE were upregulated in CRC clinical tissue samples. We identified microRNA miR-181a-5p as an inhibitory target of CRNDE. Both CRNDE knockdown and miR-181a-5p overexpression in CRC cell lines led to inhibited cell proliferation and reduced chemoresistance. We also determined that β-catenin and TCF4 were inhibitory targets of miR-181a-5p, and that Wnt/β-catenin signaling was inhibited by both CRNDE knockdown and miR-181a-5p overexpression. Significantly, we found that the repression of cell proliferation, the reduction of chemoresistance, and the inhibition of Wnt/β-catenin signaling induced by CRNDE knockdown would require the increased expression of miR-181a-5p.ConclusionsOur study demonstrated that the lncRNA CRNDE could regulate the progression and chemoresistance of CRC via modulating the expression levels of miR-181a-5p and the activity of Wnt/β-catenin signaling.Electronic supplementary materialThe online version of this article (doi:10.1186/s12943-017-0583-1) contains supplementary material, which is available to authorized users.

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Electrocatalytic CO 2 reduction (ECR) with rationally designed electrocatalysts is a promising strategy to reduce CO 2 emission and produce value-added products. Reactive sites of heterogeneous catalysts usually lie on the surface and subsurface, which allow improvement of the catalytic property by engineering the surface atoms. Defects of an electrocatalyst, such as dopants, atom vacancies, and grain boundaries, have potential to enable unconventional adsorption behaviors and chemical activities of reactants on the catalyst surface, and selectively enhance the stability of specific intermediates and corresponding ECR pathways. Moreover, the interface between two different electrocatalyst components can also stabilize active surface catalytic sites and enable their synergetic effects. In this review, we summarize how surface defects and interface can be rationally designed and functioned in ECR catalysts, and how these atomic-level controlling approaches help to promote efficiency and selectivity. The challenges and prospects are also discussed to suggest the future designs of ECR catalysts.

Rational synthesis of hybrid, earth‐abundant materials with efficient electrocatalytic functionalities are critical for sustainable energy applications. Copper is theoretically proposed to exhibit high reduction capability close to Pt, but its high diffusion behavior at elevated fabrication temperatures limits its homogeneous incorporation with carbon. Here, a Cu, Co‐embedded nitrogen‐enriched mesoporous carbon framework (CuCo@NC) is developed using, a facile Cu‐confined thermal conversion strategy of zeolitic imidazolate frameworks (ZIF‐67) pre‐grown on Cu(OH)2 nanowires. Cu ions formed below 450 °C are homogeneously confined within the pores of ZIF‐67 to avoid self‐aggregation, while the existence of CuN bonds further increases the nitrogen content in carbon frameworks derived from ZIF‐67 at higher pyrolysis temperatures. This CuCo@NC electrocatalyst provides abundant active sites, high nitrogen doping, strong synergetic coupling, and improved mass transfer, thus significantly boosting electrocatalytic performances in oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER). A high half‐wave potential (0.884 V vs reversible hydrogen potential, RHE) and a large diffusion‐limited current density are achieved for ORR, comparable to or exceeding the best reported earth‐abundant ORR electrocatalysts. In addition, a low overpotential (145 mV vs RHE) at 10 mA cm−2 is demonstrated for HER, further suggesting its great potential as an efficient electrocatalyst for sustainable energy applications.

To clarify and verify the ultralow frequency (ULF) seismomagnetic phenomena, we have performed statistical studies on the geomagnetic data observed at the Kakioka (KAK) station, Japan, during 2001-2010. We investigated the energy of ULF geomagnetic signals of the frequency around 0.01 Hz using wavelet transform analysis. To minimize the influences of artificial noises and global geomagnetic perturbations, we used only the geomagnetic data observed at nighttime (LT 2:30 A.M. to 4:00 A.M.) and utilized observations from a remote station, Kanoya, as a reference. Statistical results of superposed epoch analysis have indicated that ULF magnetic anomalies are more likely to appear before sizable earthquake events (E s > 10 8 ) rather than after them, especially 6-15 days before the events. Further statistical investigations show clearly that the ULF geomagnetic anomalies at KAK station are more sensitive to larger and closer events. Finally, we have evaluated the precursory information of ULF geomagnetic signals for local sizable earthquakes using Molchan's error diagram. The probability gain is around 1.6 against a Poisson model. The above results have indicated that the ULF seismomagnetic phenomena at KAK clearly contain precursory information and have a possibility of improving the forecasting of large earthquakes.

Solar-driven water splitting is a promising approach for renewable energy, where the development of efficient and stable bifunctional electrocatalysts for simultaneously producing hydrogen and oxygen is still challenging. Herein, combined with the hydrogen evolution reaction (HER) activity of a copper(I) complex and oxygen evolution reaction (OER) activity of cobalt-based oxides, a type of 1D copper-cobalt hybrid oxide nanowires (CuCoO-NWs) is developed via a facile two-step growth-conversion process toward a bifunctional water splitting catalyst. The CuCoO-NWs exhibit excellent catalytic performances for both HER and OER in the same basic electrolyte, with optimized low onset overpotentials and high current densities. The efficient HER activity is ascribed to the formation of Cu 2 O, while the activity for OER is primarily enabled by Co-based oxides and abundant oxygen vacancies. The CuCoO-NWs allow for the assembly of a water electrolyzer with strong alkaline media, with a current density of 10 mA cm −2 at 1.61 V. Further combination with a commercial silicon photovoltaic allows the direct use of solar energy for spontaneous water splitting with excellent stability for over 72 h, suggesting the potential as a promising bifunctional electrocatalyst for efficient solar-driven water splitting.