Constructing a solid electrolyte interface (SEI) is a highly effective approach to overcome the poor reversibility of lithium (Li) metal anodes. Herein, an adhesive and self‐healable supramolecular ...copolymer, comprising of pendant poly(ethylene oxide) (PEO) segments and ureido‐pyrimidinone (UPy) quadruple‐hydrogen‐bonding moieties, is developed as a protection layer of Li anode by a simple drop‐coating. The protection performance of in‐situ‐formed LiPEO–UPy SEI layer is significantly enhanced owing to the strong binding and improved stability arising from a spontaneous reaction between UPy groups and Li metal. An ultrathin (approximately 70 nm) LiPEO–UPy layer can contribute to stable and dendrite‐free cycling at a high areal capacity of 10 mAh cm−2 at 5 mA cm−2 for 1000 h. This coating together with the promising electrochemical performance offers a new strategy for the development of dendrite‐free metal anodes.
Stick with it: An adhesive and self‐healable supramolecular copolymer, comprising of pendant poly(ethylene oxide) segments and ureido‐pyrimidinone (Upy) hydrogen‐bonding moieties, has been developed and employed as a protection layer of a Li anode. This layer is self‐stabilizing because of a spontaneous reaction between the UPy groups and Li, enabling dendrite‐free cycling at a high areal capacity and current density.
Cesium lead halide perovskite quantum dots (QDs) have gained significant attention as next-generation optoelectronic materials; however, their properties are highly dependent on their surface ...chemistry. The surfaces of cuboidal CsPbBr3 QDs have been intensively studied by both theoretical and experimental techniques, but fundamental questions still remain about the atomic termination of the QDs. The binding sites and modes of ligands at the surface remain unproven. Herein, we demonstrate that solid-state NMR spectroscopy allows the unambiguous assignment of organic surface ligands via 1H, 13C, and 31P NMR. Surface-selective 133Cs solid-state NMR spectra show the presence of an additional 133Cs NMR signal with a unique chemical shift that is attributed to Cs atoms terminating the surface of the particle and which are likely coordinated by carboxylate ligands. Dipolar dephasing curves that report on the distance between the surface ammonium ligands and Cs and Pb were recorded using double resonance 1H{133Cs} RESPDOR and 1H{207Pb} S-REDOR experiments. Model QD surface slabs with different possible surface terminations were generated from the CsPbBr3 crystal structure, and theoretical dipolar dephasing curves considering all possible 1H–133Cs/207Pb spin pairs were then calculated. Comparison of the calculated and experimental dephasing curves indicates the particles are CsBr terminated (not PbBr2 terminated) with alkylammonium ligands substituting into some surface Cs sites, consistent with the surface-selective 133Cs NMR experiments. These results highlight the utility of high-resolution solid-state NMR spectroscopy for studying ligand binding and the surface structure of nanomaterials.
Vasculogenic mimicry (VM) is a recently discovered angiogenetic process found in many malignant tumors, and is different from the traditional angiogenetic process involving vascular endothelium. It ...involves the formation of microvascular channels composed of tumor cells; therefore, VM is considered a new model for the formation of new blood vessels in aggressive tumors, and can provide blood supply for tumor growth. Many studies have pointed out that in recent years, some clinical treatments against angiogenesis have not been satisfactory possibly due to the activation of VM. Although the mechanisms underlying VM have not been fully elucidated, increasing research on the soil "microenvironment" for tumor growth suggests that the initial hypoxic environment in solid tumors is inseparable from VM.
In this review, we describe that the stemness and differentiation potential of cancer stem cells are enhanced under hypoxic microenvironments, through hypoxia-induced epithelial-endothelial transition (EET) and extracellular matrix (ECM) remodeling to form the specific mechanism of vasculogenic mimicry; we also summarized some of the current drugs targeting VM through these processes, suggesting a new reference for the clinical treatment of tumor angiogenesis.
Overall, the use of VM inhibitors in combination with conventional anti-angiogenesis treatments is a promising strategy for improving the effectiveness of targeted angiogenesis treatments; further, considering the importance of hypoxia in tumor invasion and metastasis, drugs targeting the hypoxia signaling pathway seem to achieve good results.
Immune checkpoint blockade targeting PD-1/PD-L1 has promising therapeutic efficacy in a variety of tumors, but resistance during treatment is a major issue. In this review, we describe the utility of ...PD-L1 expression levels, mutation burden, immune cell infiltration, and immune cell function for predicting the efficacy of PD-1/PD-L1 blockade therapy. Furthermore, we explore the mechanisms underlying immunotherapy resistance caused by PD-L1 expression on tumor cells, T cell dysfunction, and T cell exhaustion. Based on these mechanisms, we propose combination therapeutic strategies. We emphasize the importance of patient-specific treatment plans to reduce the economic burden and prolong the life of patients. The predictive indicators, resistance mechanisms, and combination therapies described in this review provide a basis for improved precision medicine.
The electrolyte solvation structure and the solid-electrolyte interphase (SEI) formation are critical to dictate the morphology of lithium deposition in organic electrolytes. However, the link ...between the electrolyte solvation structure and SEI composition and its implications on lithium morphology evolution are poorly understood. Herein, we use a single-salt and single-solvent model electrolyte system to systematically study the correlation between the electrolyte solvation structure, SEI formation process and lithium deposition morphology. The mechanism of lithium deposition is thoroughly investigated using cryo-electron microscopy characterizations and computational simulations. It is observed that, in the high concentration electrolytes, concentrated Li
and anion-dominated solvation structure initiate the uniform Li nucleation kinetically and favor the decomposition of anions rather than solvents, resulting in inorganic-rich amorphous SEI with high interface energy, which thermodynamically facilitates the formation of granular Li. On the contrary, solvent-dominated solvation structure in the low concentration electrolytes tends to exacerbate the solvolysis process, forming organic-rich mosaic SEI with low interface energy, which leads to aggregated whisker-like nucleation and growth. These results are helpful to tackle the long-standing question on the origin of lithium dendrite formation and guide the rational design of high-performance electrolytes for advanced lithium metal batteries.
The reasonable design of the semiconducting metal oxides modified by noble metal element compositing and the ingenious construct of the particular microstructure have been proved to be an effective ...method to promote the gas sensing capability of chemiresistor-type sensors. Herein, Pd–SnO2 composite nanoporous structure is fabricated by a controllable and low-power hydrothermal method. A novel weak acid glucose-assisted growth method is proposed to promote the formation of nanoporous structure. Under weak acidic environment, the complete hydrolysis of precursor (SnCl4·5H2O), leading to nanocrystallines hard to grow and create a large number of small nanoparticles with an average crystallite size of ∼10 nm, which assemble to form interstitial holes between nanoparticles. The experimental results reveal that the Pd–SnO2 composite nanoporous structure exhibits prominent methane (CH4) gas sensing performances as compared with pure SnO2 nanoparticles. Especially, 2.5 mol% Pd–SnO2 composite nanoporous structure based on sensor shows an ultra-fast response of 17.60 at 3000 ppm within 3 s to reach a stable-state and fast recovers within 5 s at an operating temperature of 340 °C, it has barely been reported that the sensor based on CH4 gas presented such excellent performances. And more importantly, the sensor based on 2.5 mol% Pd–SnO2 composite nanoporous structure also possesses high repeatability and long-term stability. These results are due to the fact that the unique nanoporous structures of composite and the chemical sensitization and electronic sensitization of Pd, which provide an effective strategy to achieve eminent gas-sensing performances of CH4 gas sensors.
Gas sensor based on 2.5 mol% Pd–SnO2 composite nanoporous fabricated by a controllable and low-power hydrothermal method shows high gas response, fast response, high repeatability and long-term stability toward methane gas. Display omitted
•Pd–SnO2 nanoporous is prepared by controllable and low-power hydrothermal method at first time.•Pd–SnO2 nanoporous based gas sensor shows a high response towards methane.•Sensor has good repeatability, stability, fast response and recovery towards methane.•Nanoporous structure increases surface area and oxygen specie to promote oxidation of methane.•Pd provides an effective strategy to achieve eminent gas-sensing performances of CH4 gas sensors.
Healing soft-tissue wounds with an irregular, complicated topography in a bleeding environment demands the development of a dressing that is wet-adhesive, haemostatic, and antibacterial. To meet this ...unmet demand, we designed a flexible nanosheet (~77 nm thick) made of two layers, one is the antibacterial and haemostatic gelatin modified with dopamine (DA) and antimicrobial peptide (AMP) and mixed with Ca2+ ions as coagulation factors, and another is the mechanically strong polycaprolactone (PCL). This flexible nanosheet exhibited robust mechanical strength, continuous and effective adhesion to a topographically irregular tissue surface under a wet condition, and a high platelet adhesion capacity. Moreover, the nanosheet presented a significantly reduced clotting time of 4 min and a high bactericidal rate of nearly 100%. An in vivo evaluation of the nanosheet using both murine dorsal skin and liver models further revealed that the nanosheet could successfully seal and heal the wounds in a bleeding environment, efficiently control haemorrhaging, and exert an excellent antibacterial effect in two weeks. Our work suggests that this nanosheet holds great promise in healing the bleeding soft-tissue wounds for treating acute trauma.
New constraints are presented on the spin-dependent weakly-interacting-massive-particle- (WIMP-)nucleon interaction from the PandaX-II experiment, using a data set corresponding to a total exposure ...of 3.3×10^{4} kg day. Assuming a standard axial-vector spin-dependent WIMP interaction with ^{129}Xe and ^{131}Xe nuclei, the most stringent upper limits on WIMP-neutron cross sections for WIMPs with masses above 10 GeV/c^{2} are set in all dark matter direct detection experiments. The minimum upper limit of 4.1×10^{-41} cm^{2} at 90% confidence level is obtained for a WIMP mass of 40 GeV/c^{2}. This represents more than a factor of 2 improvement on the best available limits at this and higher masses. These improved cross-section limits provide more stringent constraints on the effective WIMP-proton and WIMP-neutron couplings.
While hydrogels enable a variety of applications in wearable sensors and electronic skins, they are susceptible to fatigue fracture during cyclic deformations owing to their inefficient fatigue ...resistance. Herein, acrylated β-cyclodextrin with bile acid is self-assembled into a polymerizable pseudorotaxane via precise host-guest recognition, which is photopolymerized with acrylamide to obtain conductive polymerizable rotaxane hydrogels (PR-Gel). The topological networks of PR-Gel enable all desirable properties in this system due to the large conformational freedom of the mobile junctions, including the excellent stretchability along with superior fatigue resistance. PR-Gel based strain sensor can sensitively detect and distinguish large body motions and subtle muscle movements. The three-dimensional printing fabricated sensors of PR-Gel exhibit high resolution and altitude complexity, and real-time human electrocardiogram signals are detected with high repeating stability. PR-Gel can self-heal in air, and has highly repeatable adhesion to human skin, demonstrating its great potential in wearable sensors.
We report new searches for solar axions and galactic axionlike dark matter particles, using the first low-background data from the PandaX-II experiment at China Jinping Underground Laboratory, ...corresponding to a total exposure of about 2.7×10^{4} kg day. No solar axion or galactic axionlike dark matter particle candidate has been identified. The upper limit on the axion-electron coupling (g_{Ae}) from the solar flux is found to be about 4.35×10^{-12} in the mass range from 10^{-5} to 1 keV/c^{2} with 90% confidence level, similar to the recent LUX result. We also report a new best limit from the ^{57}Fe deexcitation. On the other hand, the upper limit from the galactic axions is on the order of 10^{-13} in the mass range from 1 to 10 keV/c^{2} with 90% confidence level, slightly improved compared with the LUX.
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