Highly active and stable bifunctional electrocatalysts for overall water splitting are important for clean and renewable energy technologies. The development of energy‐saving electrocatalysts for ...hydrogen evolution reaction (HER) by replacing the sluggish oxygen evolution reaction (OER) with a thermodynamically favorable electrochemical oxidation (ECO) reaction has attracted increasing attention. In this study, a self‐supported, hierarchical, porous, nitrogen‐doped carbon (NC)@CuCo2Nx/carbon fiber (CF) is fabricated and used as an efficient bifunctional electrocatalyst for both HER and OER in alkaline solutions with excellent activity and stability. Moreover, a two‐electrode electrolyzer is assembled using the NC@CuCo2Nx/CF as an electrocatalyst at both cathode and anode electrodes for H2 production and selective ECO of benzyl alcohol with high conversion and selectivity. The excellent electrocatalytic activity is proposed to be mainly due to the hierarchical architecture beneficial for exposing more catalytic active sites, enhancing mass transport. Density functional theoretical calculations reveal that the adsorption energies of key species can be modulated due to the synergistic effect between CoN and CuN. This work provides a reference for the development of high‐performance bifunctional electrocatalysts for simultaneous production of H2 and high‐value‐added fine chemicals.
Hierarchical porous nitrogen‐doped carbon@CuCo2Nx/carbon fiber serving as an efficient bifunctional electrocatalyst for overall water splitting and selective electrooxidation of benzyl alcohol with excellent activity and stability is reported. The outstanding electrocatalytic performance is mainly due to the hierarchical architecture and the synergistic effects between the Co5.47N, Cu3N nanoparticles.
Subambient daytime radiative cooling (SDRC) provides a promising electricity‐ and cryogen‐free pathway for global energy‐efficiency. However, current SDRC systems require stringent surface designs, ...which are neither cost‐effective nor eco‐friendly, to selectively emit thermal radiation to outer space and simultaneously maximize solar reflectance. Here, a generic method is developed to upgrade the conventional building‐coating materials with a peculiar self‐adaptive SDRC effect through combining particle scattering, sunlight‐excited fluorescence, and mid‐infrared broadband radiation. It is also theoretically proved that heat exchange with the sky can eliminate the use of resonant microstructures and noble metal mirrors in conventional SDRC, and also leads to enhanced daytime cooling yet suppressed nighttime overcooling. When exposed to direct sunlight, the upgraded coating over an aluminum plate can achieve 6 °C (7 °C on a scale‐model building) below the ambient temperature under a solar intensity of 744 W m−2 (850 W m−2), yielding a cooling power of 84.2 W m−2. The results pave the way for practical large‐scale applications of high‐performance SDRC for human thermal comfort in buildings.
A waterborne building coating with smart subambient radiative cooling (SSRC) is created based on a new design concept, which combines particle scattering, sunlight‐excited fluorescence, and mid‐infrared broadband radiation. Consequently, conventional building‐coating materials can be engineered at low cost to realize SSRC, facilitating an eco‐friendly solution for widespread applications of the SSRC technology in buildings for improved human comfort.
Exploring highly efficient and inexpensive hydrogen evolution reaction (HER) electrocatalysts for various electrochemical energy conversion technologies is actively encouraged. Herein, a 3D ...urchin‐like Mo‐W18O49 nanostructure as an efficient HER catalyst is reported for the first time. The obtained Mo‐W18O49 catalyst exhibits excellent electrocatalytic activity toward HER with small onset potential and Tafel slope. The prepared Mo‐W18O49 electrode shows excellent durability after a long period. Density functional theory calculations reveal that the remarkably enhanced performance of Mo‐W18O49 can be due to the ability of Mo dopant to increase the number of active sites, leading to optimal hydrogen adsorption on the active sites because of the electronic and geometric modulation. In addition, the urchin‐like 3D morphology with a high surface area and abundant 1D nanowires promotes electron transfer, thereby ensuring fast interfacial charge transfer to improve electrocatalytic reactions. All these experimental and theoretical results clearly reveal that Mo‐W18O49 intrinsically improves HER activity and thus has potential applications in water splitting.
The 3D urchin‐like Mo‐W18O49 catalyst exhibits excellent electrocatalytic activity toward HER with small onset potential and Tafel slope, as well as excellent durability. The remarkably enhanced performance of Mo‐W18O49 can be ascribed to the synergistic effect of an increased amount of active sites and of activity improvment by Mo dopant, furthermore abundant agminated 1D nanowires also provide a high surface area.
Fast radio bursts (FRBs), bright transients with millisecond durations at ∼GHz and typical redshifts probably >0.8, are likely to be gravitationally lensed by intervening galaxies. Since the time ...delay between images of strongly lensed FRB can be measured to extremely high precision because of the large ratio ∼10
between the typical galaxy-lensing delay time Formula: see text (10 days) and the width of bursts Formula: see text (ms), we propose strongly lensed FRBs as precision probes of the universe. We show that, within the flat ΛCDM model, the Hubble constant H
can be constrained with a ~0.91% uncertainty from 10 such systems probably observed with the square kilometer array (SKA) in <30 years. More importantly, the cosmic curvature can be model independently constrained to a precision of ∼0.076. This constraint can directly test the validity of the cosmological principle and break the intractable degeneracy between the cosmic curvature and dark energy.
By using the thermodynamic calculation of evolution of inclusions that contain rare earths, industrial‐scale modification experiments are conducted. Energy spectroscopy analysis, field emission ...scanning electron microscopy, energy dispersive spectrometry, original morphology analysis, and Factsage 7.2 software are used to analyze the evolution mechanisms of inclusions in Al‐killed titanium‐alloyed interstitial free steel. The results reveal that different substances are formed in the following order: Ce2O3(s) > Ce2O2S(s) > CeAlO3(s) > CeO2 (s), with the wt%Ce reaching a range of 0–0.01 according to thermodynamic calculation. After Ce treatment, irregular Al2O3 inclusions with a size of 10–15 μm are wrapped by rare earth and then gradually modified into spheroidal CeAlO3, Ce2O3, and Ce2O2S inclusions with a size of ≈5 μm and distributed into interstitial free slabs. A geometric model is developed for the formation of oxide inclusions to illustrate the process of modification. The disregistries between the two‐dimensional lattice parameters of the nucleating phase (Ce2O3 and Ce2O2S) and the substrate (δ‐Fe) at the interfaces are 6.21% and 5.77%, respectively, as measured by modified calculations performed during the heterogeneous nucleation phase.
After Ce treatment, irregular Al2O3 inclusions with a size of 10–15 μm are wrapped by rare earth and then gradually modified into spheroidal CeAlO3, Ce2O3, and Ce2O2S inclusions with a size of ≈5 μm and distributed into interstitial free slabs. The disregistries between the two‐dimensional lattice parameters of the nucleating phase (Ce2O3 and Ce2O2S) and the substrate (δ‐Fe) at the interfaces are 6.21% and 5.77%, respectively.
Though essential oils exhibit antibacterial activity against food pathogens, their underlying mechanism is understudied. We extracted ginger essential oil (GEO) using supercritical CO
and steam ...distillation. A chemical composition comparison by GC-MS showed that the main components of the extracted GEOs were zingiberene and α-curcumene. Their antibacterial activity and associated mechanism against
and
were investigated. The diameter of inhibition zone (DIZ) of GEO against
was 17.1 mm, with a minimum inhibition concentration (MIC) of 1.0 mg/mL, and minimum bactericide concentration (MBC) of 2.0 mg/mL. For
the DIZ was 12.3 mm with MIC and MBC values of 2.0 mg/mL and 4.0 mg/mL, respectively. The SDS-PAGE analysis revealed that some of the electrophoretic bacterial cell proteins bands disappeared with the increase in GEO concentration. Consequently, the nucleic acids content of bacterial suspension was raised significantly and the metabolic activity of bacteria was markedly decreased. GEO could thus inhibit the expression of some genes linked to bacterial energy metabolism, tricarboxylic acid cycle, cell membrane-related proteins, and DNA metabolism. Our findings speculate the bactericidal effects of GEO primarily through disruption of the bacterial cell membrane indicating its suitability in food perseveration.
Fe/N/C is a promising non‐Pt electrocatalyst for the oxygen reduction reaction (ORR), but its catalytic activity is considerably inferior to that of Pt in acidic medium, the environment of polymer ...electrolyte membrane fuel cells (PEMFCs). An improved Fe/N/C catalyst (denoted as Fe/N/C‐SCN) derived from Fe(SCN)3, poly‐m‐phenylenediamine, and carbon black is presented. The advantage of using Fe(SCN)3 as iron source is that the obtained catalyst has a high level of S doping and high surface area, and thus exhibits excellent ORR activity (23 A g−1 at 0.80 V) in 0.1 M H2SO4 solution. When the Fe/N/C‐SCN was applied in a PEMFC as cathode catalyst, the maximal power density could exceed 1 W cm−2.
A non‐precious Fe/N/C electrocatalyst was prepared through pyrolysis of Fe(SCN)3, poly‐m‐phenylenediamine, and carbon black. The obtained Fe/N/C catalyst has high level of S doping and high surface area, and thus exhibits excellent catalytic activity for the oxygen reduction reaction in acidic solution. A polymer electrolyte membrane fuel cell using this catalyst as the cathode can yield a maximal power density as high as 1.03 W cm−2.
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Depression is a widespread psychological disorder that affects up to 20% of the world's population. Traditional Chinese medicine (TCM), with its unique curative effect in depression ...treatment, is gaining increasing attention as the discovery of novel antidepressant drug has become the pursuit of pharmaceutical. This article summarizes the work done on the natural products from TCM that have been reported to conceive antidepressant effects in the past two decades, which can be classified according to various mechanisms including increasing synaptic concentrations of monoamines, alleviating the hypothalamic-pituitary-adrenal (HPA) axis dysfunctions, lightening the impairment of neuroplasticity, fighting towards immune and inflammatory dysregulation. The antidepressant active ingredients identified can be generally divided into saponins, flavonoids, alkaloids, polysaccharides and others. Albiflorin, Baicalein, Berberine chloride, beta-Asarone, cannabidiol, Curcumin, Daidzein, Echinocystic acid (EA), Emodin, Ferulic acid, Gastrodin, Genistein, Ginsenoside Rb1, Ginsenoside Rg1, Ginsenoside Rg3, Hederagenin, Hesperidin, Honokiol, Hyperoside, Icariin, Isoliquiritin, Kaempferol, Liquiritin, L-theanine, Magnolol, Paeoniflorin, Piperine, Proanthocyanidin, Puerarin, Quercetin, Resveratrol (trans), Rosmarinic acid, Saikosaponin A, Senegenin, Tetrahydroxystilbene glucoside and Vanillic acid are Specified in this review. Simultaneously, chemical structures of the active ingredients with antidepressant activities are listed and their sources, models, efficacy and mechanisms are described. Chinese compound prescription and extracts that exert antidepressant effects are also introduced, which may serve as a source of inspiration for further development. In the view of present study, the antidepressant effect of certain TCMs are affirmative and encouraging. However, there are a lot of work needs to be done to evaluate the exact therapeutic effects and mechanisms of those active ingredients, specifically, to establish a unified standard for diagnosis and evaluation of curative effect.
Iron homeostasis disturbance has been implicated in Alzheimer's disease (AD), and excess iron exacerbates oxidative damage and cognitive defects. Ferroptosis is a nonapoptotic form of cell death ...dependent upon intracellular iron. However, the involvement of ferroptosis in the pathogenesis of AD remains elusive. Here, we report that ferroportin1 (Fpn), the only identified mammalian nonheme iron exporter, was downregulated in the brains of APPswe/PS1dE9 mice as an Alzheimer's mouse model and Alzheimer's patients. Genetic deletion of Fpn in principal neurons of the neocortex and hippocampus by breeding Fpn
mice with NEX-Cre mice led to AD-like hippocampal atrophy and memory deficits. Interestingly, the canonical morphological and molecular characteristics of ferroptosis were observed in both Fpn
and AD mice. Gene set enrichment analysis (GSEA) of ferroptosis-related RNA-seq data showed that the differentially expressed genes were highly enriched in gene sets associated with AD. Furthermore, administration of specific inhibitors of ferroptosis effectively reduced the neuronal death and memory impairments induced by Aβ aggregation in vitro and in vivo. In addition, restoring Fpn ameliorated ferroptosis and memory impairment in APPswe/PS1dE9 mice. Our study demonstrates the critical role of Fpn and ferroptosis in the progression of AD, thus provides promising therapeutic approaches for this disease.
ABSTRACT Model-independent estimations for the spatial curvature of the universe not only provide a test for the fundamental assumption of the Copernican principle, but also can effectively break the ...degeneracy between curvature and dark-energy properties. In this paper, we propose to achieve model-independent constraints on the spatial curvature from observations of standard candles and standard clocks, without assuming any fiducial cosmology or other priors. We find that, for the popular Union2.1 observations of Type Ia supernovae (SNe Ia), the spatial curvature is constrained to be . For the latest joint light-curve analysis of SNe Ia observations, we obtain . It is suggested that these results are in excellent agreement with a spatially flat universe. Moreover, compared to other approaches aiming for model-independent estimations of spatial curvature, this method also achieves constraints with competitive precision.
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