In this paper, the electrochemical behaviors of Pb(II) and Pr(III) were investigated on W electrode in LiCl–KCl melts, respectively. The results illustrated that the reduction of Pb(II) and Pr(III) ...was a one step process. When the PbCl
2
and PrCl
3
co-existed in the molten salt, the cyclic voltammetry, square wave voltammetry and open circuit chronopotentiometry illustrated that four kinds of Pb-Pr intermetallic compounds were formed at 773 K. Whereafter, the electrochemical behavior of Pr(III) on liquid Pb cathode was studied by cyclic voltammetry in LiCl–KCl melts, and the result showed that only one kind of Pb-Pr intermetallic compound was formed at 773 K. The Pr element was extracted by galvanostatic and potentiostatic electrolysis with the assistance of Pb cathode in LiCl–KCl–PrCl
3
melts, respectively. Finally, the obtained alloys were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS), and the result illustrated that the prepared intermetallic compound mainly is Pb
3
Pr.
Dual-phase heterointerface electrocatalysts (DPHE) constructed by oxygen reduction reaction (ORR)- and oxygen evolution reaction (OER)-active elements exhibit excellent bifunctional activity and ...long-term durability due to the abundant interface exposure and synergistic catalytic effect. Herein, low-dimensional N-doped graphene nanoribbons (N-GNRs) coupling with ultrathin CoO nanocomposites (N-GNRs/CoO) were controllably fabricated through a facile two-step approach using synthesized Co(OH)
2
nanosheet as CoO precursor. Density functional theory (DFT) calculations and experimental characterizations prove that the formation of interface between N-GNRs and CoO can induce local charge redistribution, contributing to the improvement of catalytic activity and stability. The optimal N-GNRs/CoO DPHE possesses hierarchically porous architectures and presents outstanding bifunctional activities with a small potential gap of 0.729 V between the potential at 10 mA·cm
−2
for OER and the halfwave potential for ORR, which outperforms Pt/C + IrO
2
and the majority of noble-metal-free bifunctional catalysts. Liquid- and solid-state rechargeable Zn–air batteries assembled with N-GNRs/CoO as the cathode also display high peak power density and fantastic cycle stability, superior to that of benchmark Pt/C + IrO
2
catalyst. It is anticipated to offer significant benefits toward high activity, stability and mechanical flexibility bifunctional oxygen electrocatalysts for rechargeable Zn–air batteries.
Graphical abstract
A new calculation approach is suggested to the fatigue life evaluation of notched specimens under multiaxial variable amplitude loading. Within this suggested approach, if the computed uniaxial ...fatigue damage by the pure torsional loading path is larger than that by the axial tension–compression loading path, a shear strain‐based multiaxial fatigue damage parameter is assigned to calculate multiaxial fatigue damage; otherwise, an axial strain‐based multiaxial fatigue damage parameter is assigned to calculate multiaxial fatigue damage. Furthermore, the presented method employs shear strain‐based and axial strain‐based multiaxial fatigue damage parameters in substitution of equivalent strain amplitude to consider the influence of nonproportional additional hardening. The experimental data of GH4169 superalloy and 7050‐T7451 aluminium alloy notched components are used to illustrate the presented multiaxial fatigue lifetime estimation approach for notched components, and the results reveal that estimations are accurate.
The exploitation of novel wound healing methods with real-time infection sensing and high spatiotemporal precision is highly important for human health. Pt-based metal-organic cycles/cages (MOCs) ...have been employed as multifunctional antibacterial agents due to their superior Pt-related therapeutic efficiency, various functional subunits and specific geometries. However, how to rationally apply these nanoscale MOCs on the macroscale with controllable therapeutic output is still challenging. Here, a centimeter-scale Pt MOC film was constructed via multistage assembly and subsequently coated on a N,N'-dimethylated dipyridinium thiazolo5,4-dthiazole (MPT)-stained silk fabric to form a smart wound dressing for bacterial sensing and wound healing. The MPT on silk fabric could be used to monitor wound infection in real-time through the bacteria-mediated reduction of MPT to its radical form via a color change. The MPT radical also exhibited an excellent photothermal effect under 660 nm light irradiation, which could not only be applied for photothermal therapy but also induce the disassembly of the Pt MOC film suprastructure. The highly ordered Pt MOC film suprastructure exhibited high biosafety, while it also showed improved antibacterial efficiency after thermally induced disassembly. In vitro and in vivo studies revealed that the combination of the Pt MOC film and MPT-stained silk can provide real-time information on wound infection for timely treatment through noninvasive techniques. This study paves the way for bacterial sensing and wound healing with centimeter-scale metal-organic materials.
Designing tough biopolymer-based hydrogels as structural biomaterials has both scientific and practical significances. We report a facile approach to prepare polysaccharide-based hydrogel films with ...remarkable mechanical performances and antiadhesion property. The hydrogel films with a thickness of 40–60 μm were prepared by mixing aqueous solutions of κ-carrageenan (κ-CG) and protonated chitosan (CS), evaporating the solvent, and then swelling the casted film in water to achieve the equilibrium state. The obtained κ-CG/CS gel films with a water content of 48–88 wt % possessed excellent mechanical properties with a breaking stress of 2–6.7 MPa and a breaking strain of 80–120%, superior to the most existing biopolymer-based hydrogels. The extraordinary mechanical properties of gel films obtained over a wide range of mass ratio of κ-CG to CS should be rooted in the synergistic effect of ionic and hydrogen bonds between the κ-CG and CS molecules. In addition, the tough gel films showed good self-recovery ability, biocompatibility, and cell antiadhesion property, making them promising as an artificial dura mater and diaphragm materials in the surgery. The design principle by incorporating multiple noncovalent bonds to toughen the biopolymer-based hydrogels should be applicable to other systems toward structural biomaterials with versatile properties.
Conductive polymer hydrogels (CPHs) that combine the unique properties of hydrogels and electronic properties of conductors have shown their great potentials in wearable/implantable electronic ...devices, where materials with remarkable mechanical properties, high conductivity, and easy processability are demanding. Here, we have developed a new type of polyion complex/polyaniline (PIC/PAni) hybrid hydrogels that are tough, conductive, and can be facilely patterned. The incorporation of conductive phase (PAni) into PIC matrix through phytic acid resulted in hybrid gels with ∼65 wt % water; high conductivity while maintaining the key viscoelasticity of the tough matrix. The gel prepared from 1 M aniline (Ani) exhibited the breaking strain, fracture stress, tensile modulus, and electrical conductivity of 395%, 1.15 MPa, 5.31 MPa, and 0.7 S/m, respectively, superior to the most existing CPHs. The mechanical and electrical performance of PIC/PAni hybrid hydrogels exhibited pronounced rate-dependent and self-recovery behaviors. The hybrid gels can effectively detect subtle human motions as strain sensors. Alternating conductive/nonconductive patterns can be readily achieved by selective Ani polymerization using stencil masks. This facile patterning method based on PIC/PAni gels can be readily scaled up for fast fabrication of wavy gel circuits and multichannel sensor arrays, enabling real-time monitoring of the large-extent and large-area deformations with various sensitivities.
Hepatocellular carcinoma (HCC) is a leading cause of cancer-associated mortality in the world. However, the anticancer effects of aucubin against HCC have yet to be reported. Cisplatin often ...decreased CD8+ tumor-infiltrating lymphocytes in the tumor microenvironment through increasing programmed death-ligand 1 (PD-L1) expression, which seriously affected the prognostic effect of cisplatin in the treatment of patients with HCC. Therefore, it is necessary to identify a novel therapeutic avenue to increase the sensitivity of cisplatin against HCC.
This study aims to evaluate the anti-tumor effect of aucubin on HCC, and also to reveal the synergistic effects and mechanism of aucubin and cisplatin against HCC.
An H22 xenograft mouse model was established for the in vivo experiments. Cancer cell proliferation was detected by MTT assay. RT-qPCR was performed to analyze CD274 mRNA expression in vitro. Western blotting was employed to determine the expression levels of the PD-L1, p-Akt, Akt, p-β-catenin, and β-catenin in vitro. Immunofluorescence was carried out to examine β-catenin nuclear accumulation in HCC cells. Immunohistochemistry was used to detect tumoral PD-L1 and CD8α expression in xenograft mouse model.
Aucubin inhibits tumor growth in a xenograft HCC mouse model, but did not affect HCC cell viability in vitro. Aucubin treatment significantly inhibited PD-L1 expression through inactivating Akt/β-catenin signaling pathway in HCC cells. Overexpression of PD-L1 dramatically reversed aucubin-mediated tumoral CD8+ T cell infiltration and alleviated the antitumor activity of aucubin in xenograft mouse model. Moreover, Cisplatin could induce the expression of PD-L1 through the activation of the Akt/β-catenin signaling pathway in HCC cells, which can be blocked by aucubin in vitro. In xenograft mouse model, cisplatin treatment induced PD-L1 expression and alleviated the infiltration of CD8+ T lymphocytes in the tumor microenvironment. Aucubin not only abrogated cisplatin-induced PD-L1 expression but also enhanced the antitumor efficacy of cisplatin in a mouse xenograft model of HCC.
Aucubin exerts antitumor activity against HCC and also enhances the antitumor activity of cisplatin by suppressing the Akt/β-catenin/PD-L1 axis.
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Anisotropic structures are ubiquitous in nature, affording fascinating morphing behaviors. Biomimetic morphing materials can be developed by spatially controlling the orientations of molecules or ...nanofillers that produce anisotropic responses and internal stresses under external stimuli. However, it remains a serious challenge to fabricate materials with sophisticated anisotropic architectures. Here, a facile strategy to fabricate morphing hydrogels with elaborately ordered structures of nanosheets, which are oriented under distributed electric field and immobilized by polymerization to form a poly(N‐isopropylacrylamide) matrix, is proposed. Diverse sophisticated anisotropic structures are obtained by engineering the electric field through the patterns and relative locations of the electrodes. Upon heating, the monolithic hydrogels with through‐thickness and/or in‐plane gradients in orientation of the nanosheets deform into various three‐dimensional configurations. After incorporating gold nanoparticles, the hydrogels become photoresponsive and capable of programmable motions, for example, dynamic twisting and flipping under spatiotemporal stimuli. Such a strategy of using patterned electrodes to generate distributed electric field should be applicable to systems of liquid crystals or charged particles/molecules to direct orientation or electrophoresis and form functional structures. The biomimetically architectured hydrogels would be ideal materials to develop artificial muscles, soft actuators/robots, and biomedical devices with versatile applications.
Biomimetic morphing hydrogels with sophisticated anisotropic structures are developed by using a distributed electric field to orient the nanosheets that are then immobilized in a thermoresponsive matrix. The electric field can be facilely tuned by structured electrodes with tailored patterns and positions. The resultant hydrogels with specific gradient of orientations exhibit programmed deformations and motions upon spatiotemporal stimulation.
MicroRNAs constitute a class of ~22-nucleotide non-coding RNAs. They modulate gene expression by associating with the 3' untranslated regions (3' UTRs) of messenger RNAs (mRNAs). Although multiple ...miRNAs are known to be regulated during myoblast differentiation, their individual roles in muscle development are still not fully understood. In this study, we showed that miR-199a-3p was highly expressed in skeletal muscle and was induced during C2C12 myoblasts differentiation. We also identified and confirmed several genes of the IGF-1/AKT/mTOR signal pathway, including IGF-1, mTOR, and RPS6KA6, as important cellular targets of miR-199a-3p in myoblasts. Overexpression of miR-199a-3p partially blocked C2C12 myoblast differentiation and the activation of AKT/mTOR signal pathway, while interference of miR-199a-3p by antisense oligonucleotides promoted C2C12 differentiation and myotube hypertrophy. Thus, our studies have established miR-199a-3p as a potential regulator of myogenesis through the suppression of IGF-1/AKT/mTOR signal pathway.
Modified cokes with improved resistance to CO
reaction were produced from a high volatile coking coal (HVC) and different concentrations of boron carbide (B
C) in a laboratory scale coking furnace. ...This paper focuses on modification mechanism about the influence of B
C on coking behavior and chemical structure during HVC carbonization. The former was studied by using a thermo-gravimetric analyzer. For the latter, four semi-cokes prepared from carbonization tests for HVC with or without B
C at 450 °C and 750 °C, respectively, were analyzed by using Fourier transform infrared spectrum and high-resolution transmission electron microscopy technologies. It was found that B
C will retard extensive condensation and crosslinking reactions by reducing the amount of active oxygen obtained from thermally produced free radicals and increase secondary cracking reactions, resulting in increasing size of aromatic layer and anisotropic degree in coke structure, which eventually improves the coke quality.
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