Search

Electrochemical synthesis of H2O2 with high productivity is a significant challenge in electrocatalysis. Herein, we develop Mg‐ion contained covalent organic frameworks (MgP‐DHTA‐COF), comprising stacked 2D layers, well‐defined skeletons, and well‐ordered monodispersed active sites, for the electrocatalytic production of H2O2 directly from O2 and H2O. The precise‐designed MgP‐DHTA‐COF achieves H2O2 selectivity up to 96%, high Faradaic efficiency of 91% and reliable stability for H2O2 synthesis in 0.10 mol L−1 KOH aqueous solution. Both experiments and simulations demonstrate that the pyrrolic‐N fixed Mg ions in the knots promote the reactivity of COF and enhance the adsorption ability of OOH*. This work provides a valuable example for the design of an efficient electrocatalyst based on COFs for H2O2 production. [ABSTRACT FROM AUTHOR]

A range of flame retardant vinyl ester resins (VERs) samples have been produced containing different contents of PEPA (1‐oxo‐4‐hydroxymethyl‐2,6,7‐trioxa‐l‐phosphabicyclo[2.2.2]octane), APP (ammonium polyphosphate), and MoO3 (molybdenum trioxide). By investigating the flame retardancy of VER samples such as limiting oxygen index and UL‐94, the synergistic flame retardance of APP, PEPA, and MoO3 has been revealed. The cone calorimeter is an instrument that measures the combustion data of samples. In the VER composites on fire, the synergistic smoke suppression effect of the APP, PEPA, and MoO3 was detected. The gas and condensed phase of VER composites with APP, PEPA, and MoO3 were tested by the thermogravimetric analysis (TGA)–Fourier transform infrared spectroscopy (FTIR) and FTIR. The char residues of samples have been studied at length by scanning electron microscopy and FTIR. The results show that the presence of MoO3 can promote the formation of PO and PO structures. [ABSTRACT FROM AUTHOR]

BACKGROUND: Current research on the differentiation of mesenchymal stem cells into endothelial cells mainly focuses on the induction of cytokines or co-culture of two types of cells. Research has been not yet reported on heat shock-treated endothelial cells inducing the differentiation of mesenchymal stem cells into endothelial cells. OBJECTIVE: To investigate the ability of heat shock-treated endothelial cells to induce bone marrow mesenchymal stem cells to differentiate into vascular endothelial cells, and to explore the angiogenic capacity of induced bone marrow mesenchymal stem cells. METHODS: Human bone marrow mesenchymal stem cells were co-cultured with heat shock-treated human umbilical vein endothelial cells in a non-contact manner. The expression of CD31, CD144, VEGFR2 and vWF in the bone marrow mesenchymal stem cells was detected by flow cytometry at 14 days after co-culture. The immunofluorescence of the cells was further verified. In vivo angiogenesis test was detected using hematoxylin-eosin staining in nude mice undergoing subcutaneous transplantation of induced and non-induced bone marrow mesenchymal stem cells. Matrigel angiogenesis test was applied to observe the angiogenic ability of induced and non-induced bone marrow mesenchymal stem cells. RESULTS AND CONCLUSION: After coculture, bone marrow mesenchymal stem cells had paving-stone like structure. Flow cytometry and cellular immunofluorescence results showed an increase in the expression of VEGFR2, vWF, CD31 and CD144 after co-culture. The hematoxylin-eosin staining of the graft showed that the induced bone marrow mesenchymal stem cells arranged in a regular manner and had an angiogenic tendency. The Matrigel angiogenesis test showed that the angiogenic ability of bone marrow mesenchymal stem cells was increased after induction compared with the control group. These findings indicate that co-culture with heat shock-treated human umbilical vein endothelial cells can promote the differentiation of mesenchymal stem cells into endothelial cells, and the specific phenotype of endothelial cells is obviously transformed, which has a certain tendency of angiogenesis. [ABSTRACT FROM AUTHOR]

With the increasing concerns on the formaldehyde (HCHO) hazard, the efficient oxidation of HCHO over affordable and harmless catalyst is of significant practical interest. Herein, the intermediate state of Mn5O8−Na1.1Mn4O8 (Na−Mn5O8) biphasic‐crystal catalyst, which features Na1.1Mn4O8‐nanosheet@ Mn5O8‐nanorod interconnected 3D structure, is successfully fabricated through the anaerobic calcination of manganite followed by alkali treatment. The resultant Na−Mn5O8 exhibits 100 % conversion of HCHO (150 ppm and 60000 h−1) and reliable stability (50 h) at 90 °C under demanding water‐free feed conditions, which is superior to that of the reference samples of Mn5O8, Na1.1Mn4O8, MnO2 and Na−MnO2. The experimental results demonstrate that the abundant structure defects (oxygen vacancies) on Na−Mn5O8, which may locate along the phase interfaces / shared‐edges of Mn5O8 nanorods and Na1.1Mn4O8 nanosheets, significantly enhance the active oxygen species and finally contribute to the high activity for HCHO oxidation. Furthermore, the 3D structure of Na−Mn5O8 favors mass transfer and fully exposing active sites for the HCHO adsorption and conversion. These findings reveal a way to enhance the catalytic activity of metal oxides via controlling the intermediate state of heteropical crystals. [ABSTRACT FROM AUTHOR]

Highlights • A novel fractal tree-like photobioreactor was designed and fabricated by 3D printer. • The fractal structure design generated good performances of multiphase flow. • Fractal tree-like photobioreactors had higher efficiency of bio-reaction. • Coupling of fractal geometry and 3D printing provide a potential development for PBR. Abstract Based on the bionic fractal theory, a fractal tree-like photobioreactor (PBR) with high surface area to volume ratio is designed on the basis of bifurcation tree algorithm and manufactured via 3D printing technology. Numerical simulation and experimental results show that the fractal structure has a good flow performance and can lead to secondary flow, which is beneficial to enhance the turbulence and produce smaller bubble sizes. Chlorella culture in the fractal tree-like PBR has a higher Fv / Fm (Chlorophyll fluorescence parameter), close to 0.767, and higher efficiency of photosynthetic growth as well as CO 2 capture, compared with multitubular PBR and conventional acrylic column reactors. Therefore, the fractal tree-like PBR can improve the efficiency of light energy utilization and bioreaction. Combined with 3D printing technology, fractal PBR blazes a new trail for process intensification on the microalgae cultivation. [ABSTRACT FROM AUTHOR]

Fast solvent-free synthesis of hierarchical SAPO-34/18 zeolite was realized by combining oil-bath heating and the addition of catalytic amount of ammonium salt. The obtained zeolite samples were systematically characterized by XRD, SEM, XRF, BET, NH3-TPD, and NMR. XRD and SEM results showed that high-quality SAPO-34/18 nano-crystals with plate morphology can be obtained in only 60 min. The addition of ammonium salt served as mineralizing agent which speeded up the crystallization process in solvent-free precursor. The fast heat transfer of oil-bath heating and seeding also contributed to the ultrafast synthesis. Nitrogen adsorption-desorption analysis indicated the presence of high BET surface area and micropore volume, as well as abundant mesopores and macropores. NH3-TPD and 29Si NMR results showed that the samples exhibited appropriate acid strength and concentration. The obtained SAPO catalysts showed excellent performance in MTO reaction with significantly longer catalytic lifetime and higher propylene and butylene selectivities, compared with micron-sized SAPO-34 catalyst made with the conventional hydrothermal method. The extended lifetime could be attributed to the thin-plate crystal morphology and hierarchical pore structure, which greatly alleviated the diffusion constrain and coke deposition in MTO reaction. Higher propylene and butylene selectivities could be ascribed to the larger size of the AEI cage, which allows the easy diffusion of longer alkenes. The realization of ultrafast synthesis with solvent-free precursor not only reduces the waste disposal and energy consumption, but also increases the autoclave efficiency significantly. [ABSTRACT FROM AUTHOR]

The ion extraction and electro/photo catalysis are promising methods to address environmental and energy issues. Covalent organic frameworks (COFs) are a class of promising template to construct absorbents and catalysts because of their stable frameworks, high surface areas, controllable pore environments, and well‐defined catalytic sites. Among them, ionic COFs as unique class of crystalline porous materials, with charges in the frameworks or along the pore walls, have shown different properties and resulting performance in these applications with those from charge‐neutral COFs. In this review, current research progress based on the ionic COFs for ion extraction and energy conversion, including cationic/anionic materials and electro/photo catalysis is reviewed in terms of the synthesis strategy, modification methods, mechanisms of adsorption and catalysis, as well as applications. Finally, we demonstrated the current challenges and future development of ionic COFs in design strategies and applications. [ABSTRACT FROM AUTHOR]

The role of resveratrol (trans‑3,5,4'‑trihydroxystilbene; RES) in lysophosphatidylcholine (LPC)‑induced injury and inflammation in endothelial cells (regarded as an early event in arteriosclerosis) is unclear. The present study investigated whether RES reduces lactate dehydrogenase (LDH) activity and secretion of inflammatory cytokines such asinterleukin‑6 and tumor necrosis factor‑α, via the Toll‑like receptor (TLR)‑4/myeloid differentiation primary response gene 88 (MyD88)/nuclear factor (NF)‑κB signal transduction pathway in LPC‑induced damage and inflammation in human umbilical vein endothelial‑12 (HUVE‑12) cells. Using an ELISA and western blotting, the present study investigated the effects of RES on LDH activity and cytokine secretion. The effects of TLR‑4 short hairpin (sh)RNA and TLR‑4 cDNA transfection on NF‑κB activation during LPC‑induced damage and inflammation was also investigated in HUVE‑12 cells. The results demonstrated that RES significantly inhibited the effect of LPC on enzyme activity, pro‑inflammatory cytokine secretion, and expression of TLR‑4, MyD88 and NF‑κBp65 expression. In addition, RES and TLR‑4 shRNA transfection suppressed LPC‑induced injury and inflammation by blocking the TLR‑4/MyD88/NF‑κB signaling pathway Conversely, transfection with TLR‑4 cDNA enhanced LPC‑induced injury and inflammation, which abrogated the protective effects of RES. These data suggested that RES significantly suppressed LPC‑induced damage and inflammation, via suppression of the TLR‑4/MyD88/NF‑κB signaling pathway, which may provide a new mechanistic evidence for the treatment of arteriosclerosis by RES. [ABSTRACT FROM AUTHOR]