Ndrg2 regulates vertebral specification in differentiating somites

AbstractIt is generally thought that vertebral patterning and identity are globally determined prior to somite formation. Relatively little is known about the regulators of vertebral specification after somite segmentation. Here, we demonstrated that Ndrg2, a tumor suppressor gene, was dynamically expressed in the presomitic mesoderm (PSM) and at early stage of differentiating somites. Loss of Ndrg2 in mice resulted in vertebral homeotic transformations in thoracic/lumbar and lumbar/sacral transitional regions in a dose-dependent manner. Interestingly, the inactivation of Ndrg2 in osteoblasts or chondrocytes caused defects resembling those observed in Ndrg2−/− mice, with a lower penetrance. In addition, forced overexpression of Ndrg2 in osteoblasts or chondrocytes also conferred vertebral defects, which were distinct from those in Ndrg2−/− mice. These genetic analyses revealed that Ndrg2 modulates vertebral identity in segmented somites rather than in the PSM. At the molecular level, combinatory alterations of the amount of Hoxc8-11 gene transcripts were detected in the differentiating somites of Ndrg2−/− embryos, which may partially account for the vertebral defects in Ndrg2 mutants. Nevertheless, Bmp/Smad signaling activity was elevated in the differentiating somites of Ndrg2−/− embryos. Collectively, our findings unveiled Ndrg2 as a novel regulator of vertebral specification in differentiating somites

Coexisting Single-Atomic Fe and Ni Sites on Hierarchically Ordered Porous Carbon as a Highly Efficient ORR Electrocatalyst

[[abstract]]The development of oxygen reduction reaction (ORR) electrocatalysts based on earth‐abundant nonprecious materials is critically important for sustainable large‐scale applications of fuel cells and metal–air batteries. Herein, a hetero‐single‐atom (h‐SA) ORR electrocatalyst is presented, which has atomically dispersed Fe and Ni coanchored to a microsized nitrogen‐doped graphitic carbon support with unique trimodal‐porous structure configured by highly ordered macropores interconnected through mesopores. Extended X‐ray absorption fine structure spectra confirm that Fe‐ and Ni‐SAs are affixed to the carbon support via FeN4 and NiN4 coordination bonds. The resultant Fe/Ni h‐SA electrocatalyst exhibits an outstanding ORR activity, outperforming SA electrocatalysts with only Fe‐ or Ni‐SAs, and the benchmark Pt/C. The obtained experimental results indicate that the achieved outstanding ORR performance results from the synergetic enhancement induced by the coexisting FeN4 and NiN4 sites, and the superior mass‐transfer capability promoted by the trimodal‐porous‐structured carbon support.[[notice]]補正完

Maximum Power Point Tracking Control for Non-Gaussian Wind Energy Conversion System by Using Survival Information Potential

In this paper, a wind energy conversion system is studied to improve the conversion efficiency and maximize power output. Firstly, a nonlinear state space model is established with respect to shaft current, turbine rotational speed and power output in the wind energy conversion system. As the wind velocity can be descried as a non-Gaussian variable on the system model, the survival information potential is adopted to measure the uncertainty of the stochastic tracking error between the actual wind turbine rotation speed and the reference one. Secondly, to minimize the stochastic tracking error, the control input is obtained by recursively optimizing the performance index function which is constructed with consideration of both survival information potential and control input constraints. To avoid those complex probability formulation, a data driven method is adopted in the process of calculating the survival information potential. Finally, a simulation example is given to illustrate the efficiency of the proposed maximum power point tracking control method. The results demonstrate that by following this method, the actual wind turbine rotation speed can track the reference speed with less time, less overshoot and higher precision, and thus the power output can still be guaranteed under the influence of non-Gaussian wind noises

Atomic Fe on hierarchically ordered porous carbon towards high-performance Lithium-sulfur batteries

Lithium-sulfur (Li-S) battery is the promising next-generation energy storage device owing to its ultra-high theoretical energy density and low cost. Unfortunately, its practical performance is significantly hindered by the poor conductivity of sulfur, huge volume change, and soluble lithium polysulfides (LiPSs). To address above issues, single iron (Fe) atoms anchored on hierarchically porous carbon substrate configured by ordered macropores and widespread mesopores/micropores (Fe[sbnd]N[sbnd]C/OC) are synthesized and acted as carbon hosts for sulfur cathodes. Single Fe atoms in Fe-N4 moieties serve as active sites to accelerate conversion kinetics of LiPSs due to strong catalytic ability, thereby the shuttle effect being obviously restrained. Meanwhile, the trimodal-porous structure provides continuous carbon framework for enhanced electrical conductivity, ordered macroporous channels bridged by mesopores for rapid Li+ diffusion, and adequate spaces to reserve sulfur volume oscillation. Consequently, sulfur-loaded Fe[sbnd]N[sbnd]C/OC (Fe[sbnd]N[sbnd]C/OC/S) cathodes exhibit an impressive specific capacity of 1442 mAh g−1 at 0.1C and maintain the capacity retention of 89.2 % after 300 cycles at 1C. It offers fresh insights for designing efficient sulfur hosts to enhance the performance of Li-S batteries. © 2022 Elsevier B.V.LTT20005; 21PJD018; National Natural Science Foundation of China, NSFC: 22108079; China Postdoctoral Science Foundation: 2020M681208National Natural Science Foundation of China [22108079]; Shanghai Pujiang Program [21PJD018]; China Postdoctoral Science Foundation [2020M681208]; Czech Ministry of Education, Youth and Sports INTER -EXCELLENCE [LTT20005]; Feringa Nobel Prize Scientist Joint Research Cente

Controlled synthesis of hierarchical polyaniline nanowires/ordered bimodal mesoporous carbon nanocomposites with high surface area for supercapacitor electrodes

A facile strategy is developed for the synthesis of hierarchical polyaniline nanowires/ordered bimodal mesoporous carbon (PANI/OBMC) composites via chemical oxidative polymerization. Structural and morphological characterizations indicate that the polyaniline nanowire arrays with 20-30 nm diameters are grown on the surface of the OBMC. The bimodal pore distribution and hierarchical nanostructure endow the PANI/OBMC composite with high surface area of 599 m2 g-1. Electrochemical performance of the hierarchical PANI/OBMC composite as supercapacitor electrode materials has been evaluated by cyclic voltammetry and galvanostatic charge-discharge techniques. The hierarchical composite with 60 wt% PANI possesses the highest specific capacitance of 517 F g-1 and outstanding cycling stability with a capacitance retention of 91.5% after 1000 cycles. The coexistence of primary mesopores and abundant small mesopores is in favor of the fast penetration of electrolyte and the unique hierarchical structure facilitates the ion diffusion and shortens the charge transfer distance, which lead to superior electrochemical performance of PANI/OBMC-60%. © 2013 Elsevier B.V. All rights reserved

Few-layer MoS2 nanosheets incorporated into hierarchical porous carbon for lithium-ion batteries

In order to overcome the serious stacking and poor conductivity of graphene-like MoS2 nanosheets, we have developed the synthesis of few-layer MoS2 nanosheets incorporated into biomass-derived hierarchical porous carbon frameworks (labeled as MoS2/C hybrids) utilizing the strong water-absorbing power of auricularia from its inherent rich porous structure. The as-obtained MoS2/C hybrids, when applied as lithium-ion batteries anode materials, show an improved specific capacity of 707.4 mA h g-1 compared with the commercial MoS2 nanosheets (580.2 mA h g-1) and the corresponding hierarchical porous carbon (215.5 mA h g-1). More meaningfully, they possess an impressive cycle life, almost without capacity fading even after 500 cycles at 1600 mA g-1. The intriguing performance is mainly attributed to the well-dispersion of few-layer MoS2 nanosheets into hierarchical porous carbon. We believe this work will provide a new insight on the design and synthesis of novel carbon-based electrode materials for potential applications in lithium-ion batteries and other clean energy devices. © 2015 Elsevier B.V.21236003, NSFC, National Natural Science Foundation of China; 21522602, NSFC, National Natural Science Foundation of ChinaNational Natural Science Foundation of China [21236003, 21522602]; Shanghai Rising-Star Program [15QA1401200]; International Science and Technology Cooperation Program of China [2015DFA51220]; 111 Project [B14018]; Fundamental Research Funds for the Central Universitie

Oxygen-vacancy and phosphorus-doping enriched NiMoO4 nanoarrays for high-energy supercapacitors

Exploring electrode materials with high effective surface and abundant active sites takes on a critical significance in achieving high-energy supercapacitors. Herein, the oxygen vacancies (Ov) and P-doping enriched NiMoO4 nanosheet arrays were synthesized through the combination of phosphorization and N2 plasma treatment. The combination strategy makes it possible to sharply increase and modulate the Ov content. The optimized P-NiMoO4-N2 is found with the highest Ov content, and the capacitive activity is well consistent with the increase in the Ov content among all samples. As revealed by experimental results, rich Ov increases the electrochemically accessible active-sites while enhancing the intrinsic conductivity. Thus, the optimized P-NiMoO4-N2 is enabled to reach a high capacity of 2180 F g−1 at a current density of 1 A g−1 and remains 83.9 % at 10 A g−1 with high cycling stability. After being assembled with activated carbon as the negative electrode, the asymmetric supercapacitor exhibits a high energy density of 56.8 Wh kg−1 at 0.75 kW kg−1 and maintains 41.6 Wh kg−1 at 15 kW kg−1. This work may create a novel path to enrich and adjust Ov in metal oxides for high-capacity and high-power supercapacitors. © 2022LTT20005; 21PJD018; National Natural Science Foundation of China, NSFC: 22075082; China Postdoctoral Science Foundation: 2020M681208; Science and Technology Commission of Shanghai Municipality, STCSM: 1852074440

Hierarchical MoS2/C@MXene composite as an anode for high-performance lithium-ion capacitors

The battery-type anodes and capacitor-type cathodes enable lithium-ion capacitors (LICs) to achieve high energy density and high power density concurrently. Nonetheless, the gap in capacity and electrochemical reaction dynamics between anodes and cathodes remains a grand challenge. In this work, we report the synthesis of hierarchical MoS2/C@MXene composite with uniform MoS2/C nanosheets grown on few MXene flakes by electrostatic flocculation and hydrothermal reaction. As a result, the restacking of MXene flakes is inhibited effectively by electrostatic flocculation, and the few-layer MXene provides abundant sites for the uniform growth of MoS2 nanosheets. Meanwhile, the amorphous carbon matrix derived from diethylenetriamine can further enhance the conductivity of MoS2 and mitigate the oxidation of MXene. Due to the desirable coupling effect between MoS2/C and MXene conductive networks, MoS2/C@MXene electrode demonstrates superior Li storage capacity. It delivers a reversible capacity of 600 mAh g−1 at 1.0 A g−1 after 700 cycles, along with excellent rate performance. Moreover, the assembled LIC device using MoS2/C@MXene as anode and three-dimensional porous carbon as cathode exhibits a high energy density of 164.5 Wh kg−1 at the power density of 225 W kg−1, and an energy density of 53.1 Wh kg−1 even at a high power density of 11.3 kW kg−1, as well as good cycling stability with capacity retention of 77.2% after 5000 cycles at 1.0 A g−1. These results indicate that MoS2/C@MXene might be promising anode materials for high-performance LICs. © 2022 Elsevier B.V.LTT20005; National Natural Science Foundation of China, NSFC: 22075082; Science and Technology Commission of Shanghai Municipality, STCSM: 18520744400; National Key Research and Development Program of China, NKRDPC: 2016YFE0131200National Natural Science Foundation of China [22075082]; National Key R & D Program of China [2016YFE0131200]; Science and Technology Committee of Shanghai Municipality [18520744400]; Czech Ministry of Ed-ucation, Youth and Sports INTER-EXCELLENCE programme [LTT20005

Coexisting Single-Atomic Fe and Ni Sites on Hierarchically Ordered Porous Carbon as a Highly Efficient ORR Electrocatalyst

© 2020 Wiley-VCH GmbH The development of oxygen reduction reaction (ORR) electrocatalysts based on earth-abundant nonprecious materials is critically important for sustainable large-scale applications of fuel cells and metal–air batteries. Herein, a hetero-single-atom (h-SA) ORR electrocatalyst is presented, which has atomically dispersed Fe and Ni coanchored to a microsized nitrogen-doped graphitic carbon support with unique trimodal-porous structure configured by highly ordered macropores interconnected through mesopores. Extended X-ray absorption fine structure spectra confirm that Fe- and Ni-SAs are affixed to the carbon support via Fe-N4 and Ni-N4 coordination bonds. The resultant Fe/Ni h-SA electrocatalyst exhibits an outstanding ORR activity, outperforming SA electrocatalysts with only Fe- or Ni-SAs, and the benchmark Pt/C. The obtained experimental results indicate that the achieved outstanding ORR performance results from the synergetic enhancement induced by the coexisting Fe-N4 and Ni-N4 sites, and the superior mass-transfer capability promoted by the trimodal-porous-structured carbon support

Ultrathin Transition Metal Dichalcogenide/3d Metal Hydroxide Hybridized Nanosheets to Enhance Hydrogen Evolution Activity

The vast majority of the reported hydrogen evolution reaction (HER) electrocatalysts perform poorly under alkaline conditions due to the sluggish water dissociation kinetics. Herein, a hybridization catalyst construction concept is presented to dramatically enhance the alkaline HER activities of catalysts based on 2D transition metal dichalcogenides (TMDs) (MoS 2 and WS 2 ). A series of ultrathin 2D-hybrids are synthesized via facile controllable growth of 3d metal (Ni, Co, Fe, Mn) hydroxides on the monolayer 2D-TMD nanosheets. The resultant Ni(OH) 2 and Co(OH) 2 hybridized ultrathin MoS 2 and WS 2 nanosheet catalysts exhibit significantly enhanced alkaline HER activity and stability compared to their bare counterparts. The 2D-MoS 2 /Co(OH) 2 hybrid achieves an extremely low overpotential of ≈128 mV at 10 mA cm -2 in 1 m KOH. The combined theoretical and experimental studies confirm that the formation of the heterostructured boundaries by suitable hybridization of the TMD and 3d metal hydroxides is responsible for the improved alkaline HER activities because of the enhanced water dissociation step and lowers the corresponding kinetic energy barrier by the hybridized 3d metal hydroxides