The scalable and sustainable manufacture of thick electrode films with high energy and power densities is critical for the large-scale storage of electrochemical energy for application in ...transportation and stationary electric grids. Two-dimensional nanomaterials have become the predominant choice of electrode material in the pursuit of high energy and power densities owing to their large surface-area-to-volume ratios and lack of solid-state diffusion
. However, traditional electrode fabrication methods often lead to restacking of two-dimensional nanomaterials, which limits ion transport in thick films and results in systems in which the electrochemical performance is highly dependent on the thickness of the film
. Strategies for facilitating ion transport-such as increasing the interlayer spacing by intercalation
or introducing film porosity by designing nanoarchitectures
-result in materials with low volumetric energy storage as well as complex and lengthy ion transport paths that impede performance at high charge-discharge rates. Vertical alignment of two-dimensional flakes enables directional ion transport that can lead to thickness-independent electrochemical performances in thick films
. However, so far only limited success
has been reported, and the mitigation of performance losses remains a major challenge when working with films of two-dimensional nanomaterials with thicknesses that are near to or exceed the industrial standard of 100 micrometres. Here we demonstrate electrochemical energy storage that is independent of film thickness for vertically aligned two-dimensional titanium carbide (Ti
C
T
), a material from the MXene family (two-dimensional carbides and nitrides of transition metals (M), where X stands for carbon or nitrogen). The vertical alignment was achieved by mechanical shearing of a discotic lamellar liquid-crystal phase of Ti
C
T
. The resulting electrode films show excellent performance that is nearly independent of film thickness up to 200 micrometres, which makes them highly attractive for energy storage applications. Furthermore, the self-assembly approach presented here is scalable and can be extended to other systems that involve directional transport, such as catalysis and filtration.
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KISLJ, NUK, SBMB, UL, UM, UPUK
Proton transfer is crucial for electrocatalysis. Accumulating cations at electrochemical interfaces can alter the proton transfer rate and then tune electrocatalytic performance. However, the ...mechanism for regulating proton transfer remains ambiguous. Here, we quantify the cation effect on proton diffusion in solution by hydrogen evolution on microelectrodes, revealing the rate can be suppressed by more than 10 times. Different from the prevalent opinions that proton transport is slowed down by modified electric field, we found water structure imposes a more evident effect on kinetics. FTIR test and path integral molecular dynamics simulation indicate that proton prefers to wander within the hydration shell of cations rather than to hop rapidly along water wires. Low connectivity of water networks disrupted by cations corrupts the fast‐moving path in bulk water. This study highlights the promising way for regulating proton kinetics via a modified water structure.
Accumulating K+ cations break the water network connectivity, and confine protons in the cation hydration shell, thus slowing the proton diffusion kinetics.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Holometabolous insects stop feeding at the final larval instar stage and then undergo metamorphosis; however, the mechanism is unclear. In the present study, using the serious lepidopteran ...agricultural pest Helicoverpa armigera as a model, we revealed that 20-hydroxyecdysone (20E) binds to the dopamine receptor (DopEcR), a G protein-coupled receptor, to stop larval feeding and promote pupation. DopEcR was expressed in various tissues and its level increased during metamorphic molting under 20E regulation. The 20E titer was low during larval feeding stages and high during wandering stages. By contrast, the dopamine (DA) titer was high during larval feeding stages and low during the wandering stages. Injection of 20E or blocking dopamine receptors using the inhibitor flupentixol decreased larval food consumption and body weight. Knockdown of DopEcR repressed larval feeding, growth, and pupation. 20E, via DopEcR, promoted apoptosis; and DA, via DopEcR, induced cell proliferation. 20E opposed DA function by repressing DA-induced cell proliferation and AKT phosphorylation. 20E, via DopEcR, induced gene expression and a rapid increase in intracellular calcium ions and cAMP. 20E induced the interaction of DopEcR with G proteins αs and αq. 20E, via DopEcR, induced protein phosphorylation and binding of the EcRB1-USP1 transcription complex to the ecdysone response element. DopEcR could bind 20E inside the cell membrane or after being isolated from the cell membrane. Mutation of DopEcR decreased 20E binding levels and related cellular responses. 20E competed with DA to bind to DopEcR. The results of the present study suggested that 20E, via binding to DopEcR, arrests larval feeding and promotes pupation.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The development of energy‐storage devices has received increasing attention as a transformative technology to realize a low‐carbon economy and sustainable energy supply. Lithium–sulfur (Li–S) ...batteries are considered to be one of the most promising next‐generation energy‐storage devices due to their ultrahigh energy density. Despite the extraordinary progress in the last few years, the actual energy density of Li–S batteries is still far from satisfactory to meet the demand for practical applications. Considering the sulfur electrochemistry is highly dependent on solid‐liquid‐solid multi‐phase conversion, the electrolyte amount plays a primary role in the practical performances of Li–S cells. Therefore, a lean electrolyte volume with low electrolyte/sulfur ratio is essential for practical Li–S batteries, yet under these conditions it is highly challenging to achieve acceptable electrochemical performances regarding sulfur kinetics, discharge capacity, Coulombic efficiency, and cycling stability especially for high‐sulfur‐loading cathodes. In this Review, the impact of the electrolyte/sulfur ratio on the actual energy density and the economic cost of Li–S batteries is addressed. Challenges and recent progress are presented in terms of the sulfur electrochemical processes: the dissolution–precipitation conversion and the solid–solid multi‐phasic transition. Finally, prospects of future lean‐electrolyte Li–S battery design and engineering are discussed.
Lean on me: The challenges, recent progress, and perspectives for lean‐electrolyte Li–S batteries are discussed in terms of the two electrochemical processes for sulfur, that is, the dissolution–precipitation conversion and the solid–solid pathway.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Although many advances have been made in the pathogenesis of epilepsy recently, the pathological mechanisms of epilepsy are still largely unknown. Exploring the pathological mechanisms and developing ...novel therapeutic strategies for epilepsy are urgently needed. A SD rat model of epilepsy was established with lithium chloride-pilocarpine. Astrocytes were isolated, cultured from 8 to 12 week rats and identified by flow cytometry and immunofluorescence. Immunohistochemical staining was used for MEF2C and NF-κB in paraffin-embedded sections. RT-qPCR and western blot were used to analyze gene expression. ELISA was used to analyze the concentration of IL-6, TNF-α and Cox-2. Cells were transfected with pcDNA-MEFC2, sh-MEFC2, pcDNA-UCA1, sh-UCA1, miR-203 mimic or miR-203 inhibitor. Cell viability was assessed by MTT assay. Dual luciferase assay was used to determine the direct interaction of lncRNA UCA1/miR-203 and miR-203/MEF2C. MEF2C was down-regulated and inhibited NF-κB expression and the secretion of IL-6 and TNF-α in epilepsy. LncRNA UCA1 was also down-regulated in epilepsy. LncRNA UCA1 over-expression increased the expression of MEF2C and its knock-down decreased MEF2C expression. Luciferase activity showed lncRNA UCA1 directly targeted miR-203 and miR-203 directly targeted MEF2C. MiR-203 suppressed the expression of MEF2C, and promoted NF-κB, phosphorylated IκB/IKK and inflammatory effectors, which was reversed by MEF2C knock-down. Moreover, lncRNA UCA1 could increase the expression of MEF2C to inhibit NF-κB, phosphorylated IκB/IKK and inflammatory effectors, which was also reversed by miR-203 mimic transfection. LncRNA UCA1 inhibited the inflammation via regulating miR-203 mediated regulation of MEF2C/NF-κB signaling in epilepsy. Our investigation elucidated novel pathological mechanisms and provided potential therapeutic targets for epilepsy.
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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
There is a growing interest in oxygen electrode catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), as they play a key role in a wide range of renewable energy ...technologies such as fuel cells, metal‐air batteries, and water splitting. Nevertheless, the development of highly‐active bifunctional catalysts at low cost for both ORR and OER still remains a huge challenge. Herein, we report a new N‐doped graphene/single‐walled carbon nanotube (SWCNT) hybrid (NGSH) material as an efficient noble‐metal‐free bifunctional electrocatalyst for both ORR and OER. NGSHs were fabricated by in situ doping during chemical vapor deposition growth on layered double hydroxide derived bifunctional catalysts. Our one‐step approach not only provides simultaneous growth of graphene and SWCNTs, leading to the formation of three dimensional interconnected network, but also brings the intrinsic dispersion of graphene and carbon nanotubes and the dispersion of N‐containing functional groups within a highly conductive scaffold. Thus, the NGSHs possess a large specific surface area of 812.9 m2 g−1 and high electrical conductivity of 53.8 S cm−1. Despite of relatively low nitrogen content (0.53 at%), the NGSHs demonstrate a high ORR activity, much superior to two constituent components and even comparable to the commercial 20 wt% Pt/C catalysts with much better durability and resistance to crossover effect. The same hybrid material also presents high catalytic activity towards OER, rendering them high‐performance cheap catalysts for both ORR and OER. Our result opens up new avenues for energy conversion technologies based on earth‐abundant, scalable, noble‐metal‐free catalysts.
N‐doped graphene/single‐walled carbon nanotube hybrids that are fabricated by in situ doping during chemical vapor deposition growth on layered double hydroxide derived bifunctional catalysts exhibit very high activity for both oxygen reduction reaction and oxygen evolution reaction. This opens up new avenues for energy conversion technologies based on earth‐abundant, scalable, noble‐metal‐free catalysts.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
On-chip energy storage is a rapidly evolving research topic, opening doors for the integration of batteries and supercapacitors at the microscale on rigid and flexible platforms. Recently, a new ...class of two-dimensional (2D) transition metal carbides and nitrides (so-called MXenes) has shown great promise in electrochemical energy storage applications. Here, we report the fabrication of all-MXene (Ti3C2Tx) solid-state interdigital microsupercapacitors by employing a solution spray-coating method, followed by a photoresist-free direct laser cutting method. Our prototype devices consisted of two layers of Ti3C2Tx with two different flake sizes. The bottom layer was stacked large-size MXene flakes (lateral dimensions of 3-6 mu m) serving mainly as current collectors. The top layer was made of small-size MXene flakes ( similar to 1 mu m) with a large number of defects and edges as the electroactive layer responsible for energy storage. Compared to Ti3C2Tx micro-supercapacitors with platinum current collectors, the all-MXene devices exhibited a much lower contact resistance, higher capacitances and better rate-capabilities. Areal and volumetric capacitances of similar to 27 mF cm-2 and similar to 357 F cm-3, respectively, at a scan rate of 20 mV s-1 were achieved. The devices also demonstrated excellent cyclic stability, with 100% capacitance retention after 10 000 cycles at a scan rate of 50 mV s-1. This study opens up a plethora of possible designs for high-performance on-chip devices employing different chemistries, flake sizes and morphologies of MXenes and their heterostructures.
The TianQin-1 satellite (TQ-1), which is the first technology demonstration satellite for the TianQin project, was launched on 20 December 2019. The first round of experiment had been carried out ...from 21 December 2019 until 1 April 2020. The residual acceleration of the satellite is found to be about 1 × 10−10 m/s2/Hz1/2 at 0.1 Hz and about 5 × 10−11 m/s2/Hz1/2 at 0.05 Hz, measured by an inertial sensor with a sensitivity of 5 × 10−12 m/s2/Hz1/2 at 0.1 Hz. The micro-Newton thrusters has demonstrated a thrust resolution of 0.1 μN and a thrust noise of 0.3 μN/Hz1/2 at 0.1 Hz. The residual noise of the satellite with drag-free control is 3 × 10−9 m/s2/Hz1/2 at 0.1 Hz. The noise level of the optical readout system is about 30 pm/Hz1/2 at 0.1 Hz. The temperature stability at temperature monitoring position is controlled to be about ±3 mK per orbit, and the mismatch between the center-of-mass of the satellite and that of the test mass is measured with a precision of better than 0.1 mm.
Background. Acute exacerbation of IPF (AE-IPF) is associated with high mortality. We studied changes in pathogen involvement during AE-IPF and explored a possible role of infection in AE-IPF. ...Objectives. Our purpose is to investigate the role of infection in AE-IPF. Methods. Overall, we recruited 170 IPF patients (48 AE-IPF, 122 stable) and 70 controls at Shanghai Pulmonary Hospital. Specific IgM against microbial pathogens and pathogens in sputum were assessed. RNA sequences of pathogens in nasopharyngeal swab of IPF patients were detected by PathChip. A panel of serum parameters reflecting immune function were assessed. Results. Antiviral/bacterial IgM was higher in IPF vs. controls and in AE-IPF vs. stable IPF. Thirty-eight different bacterial strains were detected in IPF patient sputum. Bacteria-positive results were found in 9/48 (18.8%) of AE-IPF and in 26/122 (21.3%) stable IPF. Fifty-seven different viruses were detected in nasopharyngeal swabs of IPF patients. Virus-positive nasopharyngeal swabs were found in 18/30 (60%) of tested AE-IPF and in 13/30 (43.3%) of stable IPF. AE-IPF showed increased inflammatory cytokines (IL-6, IFN-γ, MIG, IL-17, and IL-9) vs. stable IPF and controls. Mortality of AE-IPF in one year (39.5%) was higher compared to stable IPF (28.7%).Conclusions. IPF patients had different colonization with pathogens in sputum and nasopharyngeal swabs; they also displayed abnormally activated immune response, which was exacerbated during AE-IPF.
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DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
Surface reactions constitute the foundation of various energy conversion/storage technologies, such as the lithium–sulfur (Li‐S) batteries. To expedite surface reactions for high‐rate battery ...applications demands in‐depth understanding of reaction kinetics and rational catalyst design. Now an in situ extrinsic‐metal etching strategy is used to activate an inert monometal nitride of hexagonal Ni3N through iron‐incorporated cubic Ni3FeN. In situ etched Ni3FeN regulates polysulfide‐involving surface reactions at high rates. Electron microscopy was used to unveil the mechanism of in situ catalyst transformation. The Li‐S batteries modified with Ni3FeN exhibited superb rate capability, remarkable cycling stability at a high sulfur loading of 4.8 mg cm−2, and lean‐electrolyte operability. This work opens up the exploration of multimetallic alloys and compounds as kinetic regulators for high‐rate Li‐S batteries and also elucidates catalytic surface reactions and the role of defect chemistry.
Inert hexagonal Ni3N can be activated by an extrinsic metal‐incorporating strategy with in situ etching that uses cubic Ni3FeN. Vacancy‐rich Ni3FeN catalysts kinetically regulate polysulfide‐involving reactions at high rates for use in advanced lithium–sulfur batteries.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
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