7 research outputs found

    Opposite responses of global warming potential to ammonium and nitrate addition in an alpine steppe soil from Northern Tibet

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    Deposit of inorganic nitrogen (N) in different forms may divergently impact soil greenhouse gas (GHG) emissions and then aroused different feedback of global warming potential (GWP). Nevertheless, little information is available in alpine grassland ecosystems, it is far from elucidated. In this study, the effects of ammonium (NH4+-N) and nitrate (NO3--N) addition on GHG emissions were evaluated by using laboratory incubation for an alpine steppe soil in northern Tibet. Six-level N gradient was set for the incubation: 14 (2T), 28 (4T), 56 (8T), 112 (16T), 224 (32T), 448 (64T) kg.ha(-1).year(-1). Our results showed that NH4+-N and NO3--N addition significantly increased and decreased soil CO2, respectively. In general, NH4+-N addition had a stronger promotion to N2O emission and a stronger inhibition to CH4 uptake compared with NO3--N addition at same level. Besides, GHG emissions increased or decreased linearly with inorganic N addition gradient (P 84%) in alpine steppe soil from Northern Tibet. The results suggested that NO3--N input likely to be more eco-friendly than NH4+-N input in alpine steppe area, it may have implications in environmental policy related to the anthropogenic emissions of the two N forms. (C) 2020 The Authors. Published by Elsevier B.V

    Fabricating 3D macroscopic graphene-based architectures with outstanding flexibility by the novel liquid drop/colloid flocculation approach for energy storage applications

    No full text
    Inspired by “water ripples” in nature and the flocculation phenomenon in colloid chemistry, a novel liquid drop/colloid flocculation approach is developed to fabricate an extremely flexible and compressible 3D macroscopic graphene-based architecture (hydrogels or aerogels), via a new coagulation-induced self-assembly mechanism. This facile and universal technique can be achieved in a neutral, acidic, or basic coagulation bath, producing microsized hydrogels with various structures, such as mushroom, circle, disc shapes, etc. The method also allows us to introduce various guest materials in the graphene matrix using transition metal salts as the coagulating bath. A mushroom-shaped NiCo oxide/GS hybrid aerogel (diameter: 3 mm) is prepared as an example, with ultrathin NiCo oxide nanosheets in situ grown onto the surface of graphene. By employing as binder-free electrodes, these hybrid aerogels exhibit a specific capacitance of 858.3 F g–1 at 2 A g–1, as well as a good rate capability and cyclic stability. The asymmetric supercapacitor, assembling with the hybrid aerogels as cathode and graphene hydrogels as anode materials, could deliver an energy density of 21 Wh kg–1 at power density of 4500 W kg–1. The ease of synthesis and the feasibility of obtaining highly flexible aerogels with varied morphologies and compositions make this method a promising one for use in the field of biotechnology, electrochemistry, flexible electronics, and environment applications

    A mesoporous superparamagnetic iron oxide nanoparticle as a generic drug delivery system for tumor ferroptosis therapy

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    Abstract As a famous drug delivery system (DDS), mesoporous organosilica nanoparticles (MON) are degraded slowly in vivo and the degraded components are not useful for cell nutrition or cancer theranostics, and superparamagnetic iron oxide nanoparticles (SPION) are not mesoporous with low drug loading content (DLC). To overcome the problems of MON and SPION, we developed mesoporous SPIONs (MSPIONs) with an average diameter of 70 nm and pore size of 3.9 nm. Sorafenib (SFN) and/or brequinar (BQR) were loaded into the mesopores of MSPION, generating SFN@MSPION, BQR@MSPION and SFN/BQR@MSPION with high DLC of 11.5% (SFN), 10.1% (BQR) and 10.0% (SNF + BQR), demonstrating that our MSPION is a generic DDS. SFN/BQR@MSPION can be used for high performance ferroptosis therapy of tumors because: (1) the released Fe2+/3+ in tumor microenvironment (TME) can produce •OH via Fenton reaction; (2) the released SFN in TME can inhibit the cystine/glutamate reverse transporter, decrease the intracellular glutathione (GSH) and GSH peroxidase 4 levels, and thus enhance reactive oxygen species and lipid peroxide levels; (3) the released BQR in TME can further enhance the intracellular oxidative stress via dihydroorotate dehydrogenase inhibition. The ferroptosis therapeutic mechanism, efficacy and biosafety of MSPION-based DDS were verified on tumor cells and tumor-bearing mice

    Fabricating 3D Macroscopic Graphene-Based Architectures with Outstanding Flexibility by the Novel Liquid Drop/Colloid Flocculation Approach for Energy Storage Applications

    No full text
    Inspired by “water ripples” in nature and the flocculation phenomenon in colloid chemistry, a novel liquid drop/colloid flocculation approach is developed to fabricate an extremely flexible and compressible 3D macroscopic graphene-based architecture (hydrogels or aerogels), via a new coagulation-induced self-assembly mechanism. This facile and universal technique can be achieved in a neutral, acidic, or basic coagulation bath, producing microsized hydrogels with various structures, such as mushroom, circle, disc shapes, etc. The method also allows us to introduce various guest materials in the graphene matrix using transition metal salts as the coagulating bath. A mushroom-shaped NiCo oxide/GS hybrid aerogel (diameter: 3 mm) is prepared as an example, with ultrathin NiCo oxide nanosheets in situ grown onto the surface of graphene. By employing as binder-free electrodes, these hybrid aerogels exhibit a specific capacitance of 858.3 F g<sup>–1</sup> at 2 A g<sup>–1</sup>, as well as a good rate capability and cyclic stability. The asymmetric supercapacitor, assembling with the hybrid aerogels as cathode and graphene hydrogels as anode materials, could deliver an energy density of 21 Wh kg<sup>–1</sup> at power density of 4500 W kg<sup>–1</sup>. The ease of synthesis and the feasibility of obtaining highly flexible aerogels with varied morphologies and compositions make this method a promising one for use in the field of biotechnology, electrochemistry, flexible electronics, and environment applications
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