The development of robust and efficient trifunctional catalysts for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen reaction (HER) is central to regenerative metal–air ...batteries and overall water splitting. It is still a big challenge to achieve an efficient integration of three functions in one freestanding electrode. Herein, a facile and upscalable strategy is demonstrated, to construct cobalt nanoparticle‐encapsulated 3D conductive films (Co/CNFs), which were induced by in situ solid diffusion from bulk cobalt metal. Under high‐temperature, volatile cobalt species from bulk cobalt foil are trapped by the contacted nitrogen‐rich carbons, followed by catalytic growth of interconnected carbon tubes, forming the 3D structured film. This resulting film can be directly preformed as self‐supporting and binder‐free electrode, which simultaneously facilitates the ORR, OER, and HER with excellent activities and superior stability. Furthermore, such “all‐in‐one” film also exhibits remarkable performance for Zn–air batteries and overall water splitting, demonstrating its feasibility for practical applications.
A flexible and freestanding porous carbon film embedded with cobalt nanoparticles is fabricated by the in situ solid‐state diffusion between loose nitrogen‐doped carbon and compact bulk metal foil. The as‐prepared film can be directly employed as a robust and highly efficient 3D electrode for both rechargeable liquid and all‐solid‐state Zn–air batteries, and overall water splitting.
Abstract
Mounting evidence suggested that dysfunction of long non-coding RNAs (lncRNAs) is involved in a wide variety of diseases. A knowledgebase with systematic collection and curation of ...lncRNA-disease associations is critically important for further examining their underlying molecular mechanisms. In 2013, we presented the first release of LncRNADisease, representing a database for collection of experimental supported lncRNA-disease associations. Here, we describe an update of the database. The new developments in LncRNADisease 2.0 include (i) an over 40-fold lncRNA-disease association enhancement compared with the previous version; (ii) providing the transcriptional regulatory relationships among lncRNA, mRNA and miRNA; (iii) providing a confidence score for each lncRNA-disease association; (iv) integrating experimentally supported circular RNA disease associations. LncRNADisease 2.0 documents more than 200 000 lncRNA-disease associations. We expect that this database will continue to serve as a valuable source for potential clinical application related to lncRNAs. LncRNADisease 2.0 is freely available at http://www.rnanut.net/lncrnadisease/.
Nanomaterials with enzyme‐mimicking characteristics have engaged great awareness in various fields owing to their comparative low cost, high stability, and large‐scale preparation. However, the wide ...application of nanozymes is seriously restricted by the relatively low catalytic activity and poor specificity, primarily because of the inhomogeneous catalytic sites and unclear catalytic mechanisms. Herein, a support‐sacrificed strategy is demonstrated to prepare a single iron site nanozyme (Fe SSN) dispersed on the porous N‐doped carbon. With well‐defined coordination structure and high density of active sites, the Fe SSN performs prominent peroxidase‐like activity by efficiently activating H2O2 into hydroxyl radical (•OH) species. Furthermore, the Fe SSN is applied in colorimetric detection of glucose through a multienzyme biocatalytic cascade platform. Moreover, a low‐cost integrated agarose‐based hydrogel colorimetric biosensor is designed and successfully achieves the visualization evaluation and quantitative detection of glucose. This work expands the application of single‐site catalysts in the fields of nanozyme‐based biosensors and personal biomedical diagnosis.
A porous netlike N‐doped graphene with uniform single Fe sites (Fe SSN) is designed and prepared by a support‐sacrificed strategy. The Fe SSN preforms prominent peroxidase‐mimicking activity, displaying high‐efficiency catalytic activity to glucose via a low‐cost integrated agarose‐based hydrogel colorimetric biosensor. This work expands a new application of single site catalysts in the fields of nanozymes and personal point‐of‐care technologies.
Single atom catalysts (SACs) have been widely studied in the field of CO2 electroreduction, but industrial‐level current density and near‐unity product selectivity are still difficult to achieve. ...Herein, a diatomic site catalysts (DASCs) consisting of Co‐Cu hetero‐diatomic pairs is synthesized. The CoCu DASC exhibits excellent selectivity with the maximum CO Faradaic efficiency of 99.1 %. The CO selectivity can maintain above 95 % over a wide current density range from 100 mA cm−2 to 500 mA cm−2. The maximum CO partial current density can reach to 483 mA cm−2 in flow cell, far exceed industrial‐level current density requirements (>200 mA cm−2). Theoretical calculation reveals that the synergistic catalysis of the Co‐Cu bimetallic sites reduce the activation energy and promote the formation of intermediate *COOH. This work shows that the introduction of another metal atom into SACs can significantly affect the electronic structure and then enhance the catalytic activity of SACs.
A diatomic site catalyst consisting of Co‐Cu hetero‐diatomic pairs is designed via a general and facile method. Industrial‐level current density can be easily achieved in a flow cell system with the maximum CO partial current density up to 483 mA cm−2. The CO selectivity can be maintained above 95 % over a wide current density range from 100 mA cm−2 to 500 mA cm−2.
Designing and modulating the local structure of metal sites is the key to gain the unique selectivity and high activity of single metal site catalysts. Herein, we report strain engineering of curved ...single atomic iron‐nitrogen sites to boost electrocatalytic activity. First, a helical carbon structure with abundant high‐curvature surface is realized by carbonization of helical polypyrrole that is templated from self‐assembled chiral surfactants. The high‐curvature surface introduces compressive strain on the supported Fe−N4 sites. Consequently, the curved Fe−N4 sites with 1.5 % compressed Fe−N bonds exhibit downshifted d‐band center than the planar sites. Such a change can weaken the bonding strength between the oxygenated intermediates and metal sites, resulting a much smaller energy barrier for oxygen reduction. Catalytic tests further demonstrate that a kinetic current density of 7.922 mA cm−2 at 0.9 V vs. RHE is obtained in alkaline media for curved Fe−N4 sites, which is 31 times higher than that for planar ones. Our findings shed light on modulating the local three‐dimensional structure of single metal sites and boosting the catalytic activity via strain engineering.
Compressive strain engineering of curved single atomic iron‐nitrogen sites could boost the catalytic activity for electrocatalytic oxygen reduction reaction.
Developing a facile and cost‐efficient method to synthesize carbon‐based nanomaterials possessing excellent structural and functional properties has become one of the most attractive topics in energy ...conversion and storage fields. In this study, density functional theory calculation results reveal the origin of high oxygen reduction reaction (ORR) activity predominantly derived from the synergistic effect of intrinsic defects and heteroatom dopants (e.g., N, S) that modulate the bandgap and charge density distribution of carbon matrix. Under the guidance of the first‐principle prediction, by using ultralight biomass waste as precursor of C, N, and S elements, a defect‐rich and N/S dual‐doped cheese‐like porous carbon nanomaterial is successfully designed and constructed. Herein, the intrinsic defects are artfully generated in terms of alkaline and ammonia activation. The electrochemical measurements display that such a material owns a comparable ORR activity (E1/2 = 0.835 V) to the commercial Pt/C catalyst, along with splendid durability and methanol tolerance in alkali media. Furthermore, as cathode catalyst, it displays a high Zn–air battery performance. The excellent ORR activity of the catalyst can be attributed to its unique 3D porous architecture, abundant intrinsic defects, and high‐content active heteroatom dopants in the carbon matrix.
N/S‐codoped cheese‐like porous carbon nanomaterials with abundant intrinsic defects show a comparable oxygen reduction reaction activity and Zn–air battery performance to the commercial Pt/C catalyst, resulting from the synergistic effect of intrinsic defects and heteroatom dopants that modulate the bandgap and charge density distribution of carbon matrix.
Oxidative stress is recognized as free radical dyshomeostasis, which has damaging effects on proteins, lipids and DNA. However, during cell differentiation and proliferation and other normal ...physiological processes, free radicals play a pivotal role in message transmission and are considered important messengers. Organisms maintain free radical homeostasis through a sophisticated regulatory system in which these “2‐faced” molecules play appropriate roles under physiological and pathological conditions. Reactive oxygen species (ROS), including a large number of free radicals, act as redox signalling molecules in essential cellular signalling pathways, including cell differentiation and proliferation. However, excessive ROS levels can induce oxidative stress, which is an important risk factor for diabetes, cancer and cardiovascular disease. An overall comprehensive understanding of ROS is beneficial for understanding the pathogenesis of certain diseases and finding new therapeutic treatments. This review primarily focuses on ROS cellular localization, sources, chemistry and molecular targets to determine how to distinguish between the roles of ROS as messengers and in oxidative stress.
In recent years, accumulating evidence has indicated that long non-coding RNAs (lncRNAs) are powerful factors influencing the progression of multiple malignancies. Although a relationship between the ...lncRNA NEAT1 (nuclear enriched abundant transcript 1) and colorectal cancer has previously been reported, the functional mechanism underlying the involvement of NEAT1 in colorectal cancer remains unknown. In this study, we report that NEAT1 expression is up-regulated in colorectal cancer tissues, which correlates with advanced clinical features, poor overall survival and disease free survival. Up-regulated NEAT1 promotes cell proliferation and metastasis of colorectal cancer both in vitro and in vivo. Moreover, NEAT1 functions as an oncogene influencing cell viability and invasion in part by serving as a competing endogenous RNA (ceRNAs) modulating miRNA-34a expression, leading to subsequent repression of the miR-34a/SIRT1 axis and activation of the Wnt/β-catenin signaling pathway. Taken together, our study demonstrates that the lncRNA NEAT1 may serve as a prognostic biomarker and a potential therapeutic target in colorectal cancer.
•LncRNA NEAT1 was significantly up-regulated in colorectal cancer tissues, and correlated with poor overall survival.•NEAT1 was functioned as an oncogene in cell viability and invasion of colorectal cancer.•NEAT1, serving as a competing endogenous RNA, could modulate miRNA-34a expression in colorectal cancer.•NEAT1 regulates SIRT1 expression by competitively binding miR-34a of colorectal cancer.•NEAT1 promotes CRC malignant progression through Wnt/β-catenin signaling pathway of colorectal cancer.
Understanding quantitative relationships between urban elements is crucial for a wide range of applications. The observation at the macroscopic level demonstrates that the aggregated urban quantities ...(e.g., gross domestic product) scale systematically with population sizes across cities, also known as urban scaling laws. However, at the mesoscopic level, we lack an understanding of whether the simple scaling relationship holds within cities, which is a fundamental question regarding the spatial origin of scaling in urban systems. Here, by analyzing four extensive datasets covering millions of mobile phone users and urban facilities, we investigate the scaling phenomena within cities. We find that the mesoscopic infrastructure volume and socioeconomic activity scale sub- and super-linearly with the active population, respectively. For a same scaling phenomenon, however, the exponents vary in cities of similar population sizes. To explain these empirical observations, we propose a conceptual framework by considering the heterogeneous distributions of population and facilities, and the spatial interactions between them. Analytical and numerical results suggest that, despite the large number of complexities that influence urban activities, the simple interaction rules can effectively explain the observed regularity and heterogeneity in scaling behaviors within cities.
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