This work first demonstrates the improved electromagnetic interference (EMI) shielding performance of monolayer graphene on highly transparent metal-meshes of random pattern. Metal-meshes are ...fabricated on quartz substrate by lift-off based on self-cracking template and CVD graphene is directly transferred onto thin metal-meshes to construct the hierarchical graphene/metal-mesh film, by which considerable improvements both in microwave reflection and absorption can be realized in thin metal-meshes. The shielding effectiveness (SE) of the hierarchical film even exceeds the summation of those of the monolayer graphene and the metal-mesh film. Detailed analyses reveal that absorption dominates the improvement in SE for a graphene/50 nm Ag-mesh film, with a three-fold absorption coefficient as well as a slightly increased reflectivity compared to the Ag-mesh itself. The as-prepared hierarchical film primely inherits the excellent optical transmission properties from random-pattern metal-meshes with high transmittance in visual-IR spectrum, low haze and faint diffraction. Moreover, the chemical stability of metal-meshes is highly improved with the protection of graphene. We anticipate that the hierarchical graphene/metal-mesh film can be a promising material to play a great role in realization of high-performance EMI shielding in emerging optoelectronic devices such as touch panels, displays, airborne optoelectronic pods, and aviation camcorders.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Lithium–sulfur (Li–S) batteries are regarded as the most promising next‐generation energy storage systems due to their high energy density and cost‐effectiveness. However, their practical ...applications are seriously hindered by several inevitable drawbacks, especially the shuttle effects of soluble lithium polysulfides (LiPSs) which lead to rapid capacity decay and short cycling lifespan. This review specifically concentrates on the shuttle path of LiPSs and their interaction with the corresponding cell components along the moving way, systematically retrospect the recent advances and strategies toward polysulfides diffusion suppression. Overall, the strategies for the shuttle effect inhibition can be classified into four parts, including capturing the LiPSs in the sulfur cathode, reducing the dissolution in electrolytes, blocking the shuttle channels by functional separators, and preventing the chemical reaction between LiPSs and Li metal anode. Herein, the fundamental aspect of Li–S batteries is introduced first to give an in‐deep understanding of the generation and shuttle effect of LiPSs. Then, the corresponding strategies toward LiPSs shuttle inhibition along the diffusion path are discussed step by step. Finally, general conclusions and perspectives for future research on shuttle issues and practical application of Li–S batteries are proposed.
This review summarizes the recent advances and strategies to suppress the shuttle effect of lithium polysulfides (LiPSs) in lithium–sulfur batteries. These strategies are composed of using the modified sulfur hosts to immobilize LiPSs, electrolyte systems to alleviate shuttle behavior, functional separator to intercept LiPSs, and anode surface engineering to avoid the chemical reaction between LiPSs and Li.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The manganese-catalyzed α-fluoroalkenylation of arenes via C-H activation and C-F cleavage has been described. This protocol provides a very useful method for the synthesis of monofluoroalkenes with ...predominant unconventional E-isomer selectivity which complements the existing strategies for the access to these molecular architectures. In addition, the selectivity of β-defluorination in the catalytic cycle not only determines the configurations of the products but also obviates the use of external oxidants, providing a good example in the exploitation of manganese-catalyzed redox-neutral C-H transformations.
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•A multi-phase transport model, considering both crack propagation and pore structure evolution caused by FTCs, is developed.•The effects of FTCs and crack characteristics on chloride ...penetration are discussed in detail.•Three key parameters of pore structure and their effects on chloride transport are elaborated and ranked.
Reinforced concrete (RC) structures, serving in marine and cold environments, are attacked by freeze–thaw cycles (FTCs) and chloride penetration, both of which can cause serious deterioration of RC structures. Existing studies lack of models considering the development of pore structure, as well as crack propagation caused by freeze and thaw. In this study, a multi-phase numerical model is proposed for studying chloride transport in concrete under FTCs. Unlike the existing models, the diffusion coefficient in the presented work is associated with the evolution of pore structure, and the induced crack is considered to be time-dependent and propagates with cycles of freeze–thaw action. The validity of the presented model is verified against a set of third-party experiments. Some important factors, such as FTCs, crack width, porosity, connectivity and most probable pore diameter factor are elaborated to illustrate how these factors affect chloride transport. The findings can bring insights to the durability design of RC structures serving in cold or marine regions.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Aims
To explore the potential relationships among gut microbiota (GM), local brain spontaneous activity, and neuropsychological characteristics in amnestic mild cognitive impairment (aMCI) patients.
...Methods
Twenty aMCI and 22 healthy control (HC) subjects were recruited. The GM composition was determined by 16S ribosomal RNA gene sequencing. Resting‐state functional magnetic resonance imaging scans were performed, and fractional amplitude of low‐frequency fluctuations (fALFF) was calculated across different frequencies. The Spearman or Pearson correlation analysis was used to analyze the relationship between spontaneous brain activity and cognitive function, and GM composition.
Results
aMCI patients had altered GM state and local spontaneous brain activity as compared with HC subjects. Correlation analysis showed that aMCI and HC groups had different “GM‐intrinsic brain activity interaction” patterns. In aMCI group, at the typical band (0.01‐0.08 Hz), the relative abundance (RA) of Bacteroides from phylum to genus level was negatively correlated with fALFF value of cerebellar vermis IV‐V, and the Ruminococcaceae RA was negatively correlated with fALFF values of left lenticular nucleus and pallidum. The Clostridiaceae RA and Blautia RA were positively correlated with the left cerebellum lobules IV‐V at the slow‐4 band (0.027‐0.073 Hz). The Veillonellaceae RA was positively correlated with fALFF values of left precentral gyrus at the slow‐5 band (0.073‐0.08 Hz). Correlation analysis showed that Clostridium members (Lachnospiraceae and Blautia) were positively, while Veillonellaceae was negatively, correlated with cognition test. Bacteroides was positively correlated with attention and computation, and negatively correlated with the three‐stage command score.
Conclusions
aMCI patients have a specific GM‐intrinsic brain activity‐cognitive function interaction pattern.
Mounting evidences suggest the crosstalk exists between the gut microbiota (GM) and the brain. In this study, amnestic mild cognitive impairment (aMCI) subjects show changes in resting state brain activity and cognitive function that parallel to specific GM bacterial taxal populations, which suggests aMCI patients have a specific interaction pattern of gut microbiota‐intrinsic brain activity‐cognition.
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BFBNIB, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
Abstract
Threat and extinction memories are crucial for organisms’ survival in changing environments. These memories are believed to be encoded by separate ensembles of neurons in the brain, but ...their whereabouts remain elusive. Using an auditory fear-conditioning and extinction paradigm in male mice, here we discovered that two distinct projection neuron subpopulations in physical proximity within the insular cortex (IC), targeting the central amygdala (CeA) and nucleus accumbens (NAc), respectively, to encode fear and extinction memories. Reciprocal intracortical inhibition of these two IC subpopulations gates the emergence of either fear or extinction memory. Using rabies-virus-assisted tracing, we found IC-NAc projection neurons to be preferentially innervated by intercortical inputs from the orbitofrontal cortex (OFC), specifically enhancing extinction to override fear memory. These results demonstrate that IC serves as an operation node harboring distinct projection neurons that decipher fear or extinction memory under the top-down executive control from OFC.
The development of effective nitrogen-doped (N-doped) metal-free carbon nanotube electrocatalysts with high activity and stability to replace the scarce Pt-based catalysts for the oxygen reduction ...reaction (ORR) is of great importance in energy conversion devices. The hierarchical porosity and content of nitrogen atoms in carbon nanotubes play an important role in the determination of active sites. The use of metal–organic frameworks (MOFs) as templates and/or precursors to fabricate porous carbon could endow the resulting products with their merits including highly doped heteroatoms, large surface areas and controllable structures. Herein, core–shell ZnO@ZIF-8 nanorods were employed as templates and precursors to fabricate hierarchically porous N-doped carbon nanotubes (NCNTs) using a self-sacrifice template approach. The high level of graphitization and nitrogen content of the NCNTs could be tuned by adjusting the core–shell ZnO@ZIF-8 nanorod precursors and pyrolysis temperature. The obtained hierarchically porous NCNTs exhibit superior performances for the ORR in alkaline media. Impressively, NCNT-24-800, which was pyrolyzed at 800 °C, exhibits an excellent performance with a positive onset potential of 0.06 V ( vs. Ag/AgCl), a more positive half-wave potential at −0.103 V ( vs. Ag/AgCl, a positive shift of 27 mV compared with Pt/C) and a high diffusion-limited current density of 5.68 mA cm −2 at −0.8 V, which are comparable to the benchmark commercial 20 wt% Pt/C catalyst. Furthermore, compared with the traditional Pt/C, the NCNTs show excellent long term stability and methanol tolerance. The self-sacrifice template approach could open up a new avenue towards the fabrication of materials with unique porous structures from MOFs as highly efficient metal-free electrocatalysts for the ORR.
An emerging concept is that the hypothalamic nutrient sensor can regulate peripheral energy metabolism via a brain-liver circuit. Valine is an essential branched-chain amino acid (BCAA) that drives ...intracellular signaling cascades by the activation of target of rapamycin complex 1 (TORC1) which is critical to protein metabolism in mammals. However, in teleost fish, it remains scarce in this area especially about how the intraventricular (ICV) injection of valine can mediate the protein metabolism in peripheral organs. This study would tentatively explore the effects of ICV injection of valine on protein metabolism in peripheral organs through evaluating the postprandial ammonia-N excretion rate in Chinese perch. The control group was injected with 5-μL PBS, and the Val group was injected with 20-μg L valine dissolved into 5-μL PBS. The ammonia-N excretion rate of Val group was lower than control group at 4-, 12-, and 24-h postinjection, while the concertation of plasma glucose was increased sharply at 0.5-, 4-, 12-, and 24-h postinjection. We further checked both mRNA level and the enzyme activity of glutamate dehydrogenase (GDH) in the liver and adenosine monophosphate deaminase (AMPD) in muscle, and we found that they were obviously decreased in Val group at 4-, 12-, and 24-h postinjection. The phosphorylation level of ribosomal protein S6, a downstream target protein of TORC1, was markedly enhanced in the liver of Val group at 4-, 12-, and 24-h postinjection. Collectively, these results illustrated that ICV injection of valine can attenuate protein degradation in peripheral organs by depressing the GDH and AMPD enzyme activity; on the other hand, the injected valine can trigger the activation of TORC1 in the liver via a brain-liver circuit and then interdict proteolysis.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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•A general method that extends diffractive deep neural networks from terahertz spectrum to visible wavelengths is proposed.•An improved formula is proposed to solve contradictions ...between wavelength, neuron size and fabrication limitation.•The diffractive deep neural networks at visible wavelengths can implement covered and altered target classification.
Optical deep learning based on diffractive optical elements offers unique advantages for parallel processing, computational speed, and power efficiency. One landmark method is the diffractive deep neural network (D2NN) based on three-dimensional printing technology operated in the terahertz spectral range. Since the terahertz bandwidth involves limited interparticle coupling and material losses, this paper extends D2NN to visible wavelengths. A general theory including a revised formula is proposed to solve any contradictions between wavelength, neuron size, and fabrication limitations. A novel visible light D2NN classifier is used to recognize unchanged targets (handwritten digits ranging from 0 to 9) and targets that have been changed (i.e., targets that have been covered or altered) at a visible wavelength of 632.8 nm. The obtained experimental classification accuracy (84%) and numerical classification accuracy (91.57%) quantify the match between the theoretical design and fabricated system performance. The presented framework can be used to apply a D2NN to various practical applications and design other new applications.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Idiopathic pulmonary fibrosis (IPF) is a chronic progressive lung disease that typically leads to respiratory failure and death within 3–5 years of diagnosis. Sub-pleural pulmonary fibrosis is a ...pathological hallmark of IPF. Bleomycin treatment of mice is a an established pulmonary fibrosis model. We recently showed that bleomycin-induced epithelial-mesenchymal transition (EMT) contributes to pleural mesothelial cell (PMC) migration and sub-pleural pulmonary fibrosis. MicroRNA (miRNA) expression has recently been implicated in the pathogenesis of IPF. However, changes in miRNA expression in PMCs and sub-pleural fibrosis have not been reported. Using cultured PMCs and a pulmonary fibrosis animal model, we found that miR-18a-5p was reduced in PMCs treated with bleomycin and that downregulation of miR-18a-5p contributed to EMT of PMCs. Furthermore, we determined that miR-18a-5p binds to the 3′ UTR region of transforming growth factor β receptor II (TGF-βRII) mRNA, and this is associated with reduced TGF-βRII expression and suppression of TGF-β-Smad2/3 signaling. Overexpression of miR-18a-5p prevented bleomycin-induced EMT of PMC and inhibited bleomycin-induced sub-pleural fibrosis in mice. Taken together, our data indicate that downregulated miR-18a-5p mediates sub-pleural pulmonary fibrosis through upregulation of its target, TGF-βRII, and that overexpression of miR-18a-5p might therefore provide a novel approach to the treatment of IPF.
Sub-pleural pulmonary fibrosis is a pathological hallmark of idiopathic pulmonary fibrosis (IPF). Zhang et al. found that downregulated miR-18a-5p mediates sub-pleural pulmonary fibrosis through upregulation of its target, TGF-βRII, suggesting that overexpression of miR-18a-5p might be an approach to the treatment of IPF.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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