Metal-organic frameworks (MOFs) have been recognized as compelling platforms for the development of miscellaneous applications because of their structural diversity and functional tunability. Here, we propose that the electrocatalytic properties could be well modified by incorporating missing linkers into the MOF. Theoretical calculations suggest the electronic structure of MOFs can be tuned by introducing missing linkers, which improves oxygen evolution reaction (OER) performance of the MOF. Inspired by these aspects, we introduced various missing linkers into a layered-pillared MOF Co2(OH)2(C8H4O4) (termed as CoBDC) to prepare missing-linker MOFs. Transmission electron microscope and synchrotron X-ray measurements confirmed that the missing linkers in the MOF could be introduced and well controlled by our strategy. The self-supported MOF nanoarrays with missing linkers of carboxyferrocene exhibit excellent OER performance with ultralow overpotential of 241 mV at 100 mA cm−2. This work opens a new prospect to develop efficient MOF-based electrocatalysts by introducing missing linkers.

Developing high-performance electrocatalysts toward hydrogen evolution reaction is important for clean and sustainable hydrogen energy, yet still challenging. Herein, we report a single-atom strategy to construct excellent metal-organic frameworks (MOFs) hydrogen evolution reaction electrocatalyst (NiRu0.13-BDC) by introducing atomically dispersed Ru. Significantly, the obtained NiRu0.13-BDC exhibits outstanding hydrogen evolution activity in all pH, especially with a low overpotential of 36 mV at a current density of 10 mA cm−2 in 1 M phosphate buffered saline solution, which is comparable to commercial Pt/C. X-ray absorption fine structures and the density functional theory calculations reveal that introducing Ru single-atom can modulate electronic structure of metal center in the MOF, leading to the optimization of binding strength for H2O and H*, and the enhancement of HER performance. This work establishes single-atom strategy as an efficient approach to modulate electronic structure of MOFs for catalyst design.

Solid oxide fuel cells (SOFC) are highly efficient energy conversion devices with the advantage of directly utilizing hydrocarbon fuels. Starting with a short introduction about the fuel challenges and early achievements in this field, this review paper focuses on advances in oxygen‐ion conducting electrolyte‐based SOFC during the last 15 years. Robust anodes immune to carbon deposition are a prerequisite for direct hydrocarbon SOFC. In this paper, direct hydrocarbon SOFC anode materials are classified into three general categories: Ni‐cermet, Cu‐cermet, and oxide‐based anodes. Oxide anodes are further classified in terms of their crystalline structures, namely fluorite, rutile, tungsten bronze, pyrochlore, perovskite, and double perovskite. Achievements and recent advances on these SOFC anodes are reviewed and discussed. The concluding remarks summarize the pros and cons of direct hydrocarbon SOFC anode materials along with the perspective of future research trends.

No abstract

Interface engineering has been recognized as one of the most promising strategies for regulating the physical and chemical properties of materials. However, constructing well‐defined nanointerfaces with efficient oxygen evolution reaction (OER) still remains a challenge. Herein, cross columnar NiTe nanoarrays supported on nickel foam are prepared. Subsequently, NiTe/NiS nanointerfaces are constructed by an ion‐exchange process. Importantly, the electrocatalytic performance for the OER can be facilitated by coupling NiTe and NiS. As a result, NiTe/NiS shows excellent OER activity with an ultralow overpotential of only 257 mV at a current density of 100 mA cm−2, and a Tafel slope of 49 mV dec−1 in 1.0 m KOH. The calculated and experimental results reveal that the strong electron interaction on nanointerfaces induces electronic structure modulation, which optimizes the binding energy of *OOH intermediates, thus improving the OER performance.

While immunosuppressive environments mediated by myeloid-derived suppressor cells (MDSCs) have been well documented in glioma patients, the mechanisms of MDSC development and activation have not been clearly defined. Here, we elucidated a role for glioma-derived exosomes (GDEs) in potentiating an MDSC pathway. We isolated normoxia-stimulated and hypoxia-stimulated GDEs and studied their MDSC induction abilities in vivo and in vitro. Analyses of spleen and bone marrow MDSC proportions (flow cytometry) and reactive oxygen species (ROS), arginase activity, nitric oxide (NO), T-cell proliferation and immunosuppressive cytokine (IL-10 and TGF-β, ELISA) levels were used to assess MDSC expansion and functional capacity. We also performed microRNA (miRNA) sequencing analysis of two types of GDEs to find miRNAs that potentially mediate the development and activation of MDSCs. GDE miRNA intracellular signaling in MDSCs was also studied. Hypoxia promoted the secretion of GDEs, and mouse MDSCs could uptake GDEs. Hypoxia-stimulated GDEs had a stronger ability to induce MDSCs than N-GDEs. The hypoxia-inducible expression of miR-10a and miR-21 in GDEs mediated GDE-induced MDSC expansion and activation by targeting RAR-related orphan receptor alpha (RORA) and phosphatase and tensin homolog (PTEN). Mice inoculated with miR-10a or miR-21 knockout glioma cells generated fewer MDSCs than those inoculated with normal glioma cells. These data elucidated a mechanism by which glioma cells influence the differentiation and activation of MDSCs via exosomes and demonstrated how local glioma hypoxia affects the entirety of tumor immune environments.

Interleukin-6 (IL-6) is a growth and survival factor in human glioblastoma cells and plays an important role in malignant progression. However, its role in glioblastoma invasion is still unknown. This study shows how IL-6 promotes cell invasion and migration in U251 and T98G glioblastoma cell lines. The underlying mechanism includes both protease-dependent and -independent manners. Stimulation with IL-6 increased MMP9 expression in the two cell lines but had no influence on MMP2 expression. Fascin-1 is a cell skeleton binding protein and plays a key role in cell migration and invasion. Its binding style directly influences cell morphology and tendency to become deformed. After IL-6 exposure, fascin-1 expression increased in an IL-6 dose-dependent manner. Immunofluorescence also revealed that the binding style of fascin-1 had changed after IL-6 exposure, resulting in a more invasive phenotype of the cells. Three most commonly emphasized invasion-associated signaling pathways, including JAK-STAT3, p42/44 MAPK, and PI3K/AKT, were verified to further illustrate its underlying mechanism. Only phosphorylation of STAT3 at ser 727 site paralleled the IL-6 stimulation, and JSI-124, a specific JAK-STAT3 pathway blocker, deterred the invasion and migration promotive effect of IL-6, indicating that the JAK/STAT3 pathway mediates signal transduction. Furthermore, IL-6 also acts in a paracrine fashion to promote vascular endothelial cell migration, thus facilitating tumor angiogenesis and invasion. These results suggest that IL-6 promotes glioblastoma cell invasion and angiogenesis and may be a potential anti-invasion target.

Hypoxia induces protective autophagy in glioblastoma cells and new therapeutic avenues that target this process may improve the outcome for glioblastoma patients. Recent studies have suggested that the autophagic process is upregulated in glioblastomas in response to extensive hypoxia. Hypoxia also induces the upregulation of a specific set of proteins and microRNAs (miRNAs) in a variety of cell types. IL6 (interleukin 6), an inflammatory autocrine and paracrine cytokine that is overexpressed in glioblastoma, has been reported to be a biomarker for poor prognosis because of its tumor-promoting effects. Here, we describe a novel tumor-promoting mechanism of IL6, whereby hypoxia-induced IL6 acts as a potent initiator of autophagy in glioblastoma via the phosphorylated (p)-STAT3-MIR155-3p pathway. IL6 and p-STAT3 levels correlated with the abundance of autophagic cells and HIF1A levels in human glioma tissues and with the grade of human glioma, whereas inhibition of exogenous or endogenous IL6 repressed autophagy in glioblastoma cells in vitro. Knockdown of endogenous MIR155-3p inhibited IL6-induced autophagy, and enforced expression of MIR155-3p restored the anti-autophagic activity of IL6 inhibitors. We show that the hypoxia-IL6-p-STAT3-MIR155-3p-CREBRF-CREB3-ATG5 pathway plays a central role in malignant glioma progression, with blockade of the IL6 receptor by tocilizumab demonstrating a certain level of therapeutic efficacy in a xenograft model in vivo, especially in combination with temozolomide. Moreover, tocilizumab inhibits autophagy by promoting tumor apoptosis. Collectively, our findings provide new insight into the molecular mechanisms underlying hypoxia-induced glioma cell autophagy and point toward a possible efficacious adjuvant therapy for glioblastoma patients.