Flexible supercapacitors (SCs) have attracted increasing attention as the power supply unit for portable/wearable electronics. Carbon nanotubes (CNTs) are promising candidate materials for flexible ...SC electrodes because of their outstanding mechanical property, high electrical conductivity, large surface area, and functionability. CNTs can assemble into various macroscopic materials with different dimensions. In this review, flexible CNT assemblies including 1D fibers, 2D films, and 3D aerogels and sponges are introduced with a focus on the design strategies and fabrication techniques. The recent developments and state-of-the-art applications of such structures as electrodes in flexible SCs are summarized based on device configurations including sandwiched, interdigital in-plane, and cable-type configurations. The flexible CNT-based electrodes have shown great advantages in bendability, stretchability and/or compressibility, as well as a long cycle lifetime. The current challenges and future research opportunities in this field are also discussed.
A series of zirconium polyphenolate‐decorated‐(metallo)porphyrin metal–organic frameworks (MOFs), ZrPP‐n (n = 1, 2), featuring infinite ZrIV‐oxo chains linked via polyphenolate groups on four ...peripheries of eclipse‐arranged porphyrin macrocycles, are successfully constructed through a top–down process from simulation to synthesis. These are the unusual examples of Zr‐MOFs (or MOFs in general) based on phenolic porphyrins, instead of commonly known carboxylate‐based types. Representative ZrPP‐1 not only exhibits strong acid resistance (pH = 1, HCl) but also remains intact even when immersed in saturated NaOH solution (≈20 m), an exceptionally large range of pH resistance among MOFs. The metallation at the porphyrin core gives rise to materials with enhanced sorption and catalytic properties. In particular, ZrPP‐1‐Co, with precise and uniform distribution of active centers, exhibits not only high CO2 trapping capability (≈90 cm3 g−1 at 1 atm, 273 K, among the highest in Zr‐MOFs) but also high photocatalytic activity for reduction of CO2 into CO (≈14 mmol g−1 h−1) and high selectivity over CH4 (>96.4%) without any cocatalyst under visible‐light irradiation (λ > 420 nm). Given the strong chemical resistance under extreme alkali conditions, these catalysts can be recycled without appreciable loss of activity. The possible mechanism for photocatalytic reduction of CO2‐to‐CO over ZrPP‐1‐Co is also proposed.
Top–down fabrication of robust and porous materials based on infinite ZrIV‐polyphenolate chains linked via eclipsed‐arranged porphyrin macrocycles is presented. Among them, ZrPP‐1 retains its framework integrity when immersed in saturated NaOH solution as long as 1 week. Moreover, metallation at the porphyrin core gives rise to materials with enhanced CO2 trapping capability and high visible‐light‐driven CO2‐to‐CO photoreduction activity.
As a model system of 2-D oxide material, layered δ-MnO2 has important applications in Li ion battery systems. δ-MnO2 is also widely utilized as a precursor to synthesize other stable structure ...variants in the MnO2 family, such as α-, β-, R-, and γ-phases, which are 3-D interlinked structures with different tunnels. By utilizing the stochastic surface walking (SSW) pathway sampling method, we here for the first time resolve the atomistic mechanism and the kinetics of the layer-to-tunnel transition of MnO2, that is, from δ-MnO2 to the α-, β-, and R-phases. The SSW sampling determines the lowest-energy pathway from thousands of likely pathways that connects different phases. The reaction barriers of layer-to-tunnel phase transitions are found to be low, being 0.2–0.3 eV per formula unit, which suggests a complex competing reaction network toward different tunnel phases. All the transitions initiate via a common shearing and buckling movement of the MnO2 layer that leads to the breaking of the Mn–O framework and the formation of Mn3+ at the transition state. Important hints are thus gleaned from these lowest-energy pathways: (i) the large pore size product is unfavorable for the entropic reason; (ii) cations are effective dopants to control the kinetics and selectivity in layer-to-tunnel transitions, which in general lowers the phase transition barrier and facilitates the creation of larger tunnel size; (iii) the phase transition not only changes the electronic structure but also induces the macroscopic morphology changes due to the interfacial strain.
Layilin (LAYN) is a critical gene that regulates T cell function. However, the correlations of LAYN to prognosis and tumor-infiltrating lymphocytes in different cancers remain unclear.
LAYN ...expression was analyzed via the Oncomine database and Tumor Immune Estimation Resource (TIMER) site. We evaluated the influence of LAYN on clinical prognosis using Kaplan-Meier plotter, the PrognoScan database and Gene Expression Profiling Interactive Analysis (GEPIA). The correlations between LAYN and cancer immune infiltrates was investigated via TIMER. In addition, correlations between LAYN expression and gene marker sets of immune infiltrates were analyzed by TIMER and GEPIA.
A cohort (GSE17536) of colorectal cancer patients showed that high LAYN expression was associated with poorer overall survival (OS), disease-specific survival (DSS), and disease-free survival (DFS). In addition, high LAYN expression was significantly correlated with poor OS and progression-free survival (PFS) in gastric cancers (OS HR = 1.97,
= 3.6e-10; PFS HR = 2.12,
= 2.3e-10). Moreover, LAYN significantly impacts the prognosis of diverse cancers via The Cancer Genome Atlas (TCGA). Specifically, high LAYN expression was correlated with worse OS and PFS in stage 2 to 4 but not stage 1 and stage N0 gastric cancer patients (
= 0.28, 0.34;
= 0.073, 0.092). LAYN expression was positively correlated with infiltrating levels of CD4+ T and CD8+ T cells, macrophages, neutrophils, and dendritic cells (DCs) in colon adenocarcinoma (COAD) and stomach adenocarcinoma (STAD). LAYN expression showed strong correlations with diverse immune marker sets in COAD and STAD.
These findings suggest that LAYN is correlated with prognosis and immune infiltrating levels of, including those of CD8+ T cells, CD4+ T cells, macrophages, neutrophils, and DCs in multiple cancers, especially in colon and gastric cancer patients. In addition, LAYN expression potentially contributes to regulation of tumor-associated macrophages (TAMs), DCs, T cell exhaustion and Tregs in colon and gastric cancer. These findings suggest that LAYN can be used as a prognostic biomarker for determining prognosis and immune infiltration in gastric and colon cancers.
Lithium metal based anode with hierarchical structure to enable high rate capability, volume change accommodation, and dendritic suppression is highly desirable for all-solid-state lithium metal ...battery. However, the fabrication of hierarchical lithium metal based anode is challenging due to the volatility of lithium. Here, we report that natural diatomite can act as an excellent template for constructing hierarchical silicon-lithium based hybrid anode for high performance all-solid-state lithium metal battery. This hybrid anode exhibits stable lithium stripping/plating performance over 1000 h with average overpotential lower than 100 mV without any short circuit. Moreover, all-solid-state full cell using this lithium metal composite anode to couple with lithium iron phosphate cathode shows excellent cycling stability (0.04% capacity decay rate for 500 cycles at 0.5C) and high rate capability (65 mAh g
at 5C). The present natural diatomite derived hybrid anode could further promote the fabrication of high performance all-solid-state lithium batteries from sustainable natural resources.
The axon initial segment (AIS) is the site of action potential generation and a locus of activity-dependent homeostatic plasticity. A multimeric complex of sodium channels, linked via a cytoskeletal ...scaffold of ankyrin G and beta IV spectrin to submembranous actin rings, mediates these functions. The mechanisms that specify the AIS complex to the proximal axon and underlie its plasticity remain poorly understood. Here we show phosphorylated myosin light chain (pMLC), an activator of contractile myosin II, is highly enriched in the assembling and mature AIS, where it associates with actin rings. MLC phosphorylation and myosin II contractile activity are required for AIS assembly, and they regulate the distribution of AIS components along the axon. pMLC is rapidly lost during depolarization, destabilizing actin and thereby providing a mechanism for activity-dependent structural plasticity of the AIS. Together, these results identify pMLC/myosin II activity as a common link between AIS assembly and plasticity.
•Phosphorylated myosin light chain (pMLC) is enriched in axon initial segments (AISs)•pMLC is associated with the actin rings in the AIS, as imaged by STORM•Inhibiting MLC phosphorylation and myosin II activity blocks assembly of the AIS•pMLC is rapidly lost with depolarization, destabilizing actin and the AIS
Berger et al. demonstrate that pMLC, a key regulator of contractile myosin II, is enriched in the axon initial segment (AIS) and is associated with actin rings. They show that pMLC and myosin II have major roles in AIS assembly and activity-dependent plasticity.
The difluoromethyl group (CF2H) is of great interest in the area of medicinal chemistry. However, the investigation of molecular scaffolds containing this group has been hampered by the limitation of ...synthetic methods for the introduction of CF2H into heteroarenes. Herein we disclose a new strategy for the direct introduction of a difluoromethyl group into heteroarenes via the copper-mediated C–H oxidative difluoromethylation of heteroarenes with TMSCF2H. This mild and regioselective method enables the convenient synthesis of a range of difluoromethylated heteroarenes in high yields. The usage of 9,10-phenanthrenequinone (PQ) as an oxidant is critical to the success of this new difluoromethylation reaction.
Abstract
Supported ordered intermetallic compounds exhibit superior catalytic performance over their disordered alloy counterparts in diverse reactions. But the synthesis of intermetallic compounds ...catalysts often requires high-temperature annealing that leads to the sintering of metals into larger crystallites. Herein, we report a small molecule-assisted impregnation approach to realize the general synthesis of a family of intermetallic catalysts, consisting of 18 binary platinum intermetallic compounds supported on carbon blacks. The molecular additives containing heteroatoms (that is, O, N, or S) can be coordinated with platinum in impregnation and thermally converted into heteroatom-doped graphene layers in high-temperature annealing, which significantly suppress alloy sintering and insure the formation of small-sized intermetallic catalysts. The prepared optimal PtCo intermetallics as cathodic oxygen-reduction catalysts exhibit a high mass activity of 1.08 A mg
Pt
–1
at 0.9 V in H
2
-O
2
fuel cells and a rated power density of 1.17 W cm
–2
in H
2
-air fuel cells.
Background and Purpose
Glial cell‐derived neurotrophic factor (GDNF) maintains gut homeostasis. Dopamine promotes GDNF release in astrocytes. We investigated the regulation by dopamine of colonic ...GDNF secretion.
Experimental Approach
D1 receptor knockout (D1R−/−) mice, adeno‐associated viral 9‐short hairpin RNA carrying D2 receptor (AAV9‐shD2R)‐treated mice, 6‐hydroxydopamine treated (6‐OHDA) rats and primary enteric glial cells (EGCs) culture were used. Incubation fluid from colonic submucosal plexus and longitudinal muscle myenteric plexus were collected for GDNF and ACh measurements.
Key Results
D2 receptor‐immunoreactivity (IR), but not D1 receptor‐IR, was observed on EGCs. Both D1 receptor‐IR and D2 receptor‐IR were co‐localized on cholinergic neurons. Low concentrations of dopamine induced colonic GDNF secretion in a concentration‐dependent manner, which was mimicked by the D1 receptor agonist SKF38393, inhibited by TTX and atropine and eliminated in D1R−/− mice. SKF38393‐induced colonic ACh release was absent in D1R−/− mice. High concentrations of dopamine suppressed colonic GDNF secretion, which was mimicked by the D2 receptor agonist quinpirole, and absent in AAV‐shD2R‐treated mice. Quinpirole decreased GDNF secretion by reducing intracellular Ca2+ levels in primary cultured EGCs. Carbachol ( ACh analogue) promoted the release of GDNF. Quinpirole inhibited colonic ACh release, which was eliminated in the AAV9‐shD2R‐treated mice. 6‐OHDA treated rats with low ACh and high dopamine content showed decreased GDNF content and increased mucosal permeability in the colon.
Conclusion and Implications
Low concentrations of dopamine promote colonic GDNF secretion via D1 receptors on cholinergic neurons, whereas high concentrations of dopamine inhibit GDNF secretion via D2 receptors on EGCs and/or cholinergic neurons.
The solid phase transition of TiO2, in particular anatase to rutile, has been extensively studied in the past 30 years. To seek the nucleation site at the beginning of phase transition is highly ...challenging, which asks for new theoretical techniques with high spatial and temporal resolution. This work reports the first evidence on the atomic structure of the nucleation sites in the TiO2 anatase-to-rutile phase transition. Novel automated theoretical methods, namely stochastic surface walking based pathway sampling methods, are utilized to resolve the lowest energy pathways at the initial stage of phase transition. We show that among common anatase surfaces, only the (112) ridged surface provides the nucleation site for phase transition, which can lead to the formation of both TiO2-II and brookite thin slabs. The TiO2-II phase is kinetically preferred product; the propagation into the subsurface is still hindered by high barriers that is the origin for the slow kinetics of nuclei formation. The rutile nuclei are thus not rutile phase but nascent metastable TiO2-II phase in an anatase matrix. The phase transition kinetics is found to be sensitive to the compressive strain and the crystallographic directions. The results rationalize the size and morphology dependence of the anisotropic phase transition kinetics of anatase particles and could facilitate the rational design of material via controlled solid phase transition.
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