Three-dimensionally ordered mesoporous carbon sphere array (OMCS)-supported Pt nanoparticles (Pt/OMCS) were synthesized and studied as electrocatalysts for the methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR). In the Pt/OMCS, the Pt particles with a mean size of ∼1.6 nm are homogeneously dispersed on the mesopore walls of the carbon spheres. The Pt/OMCS catalyst exhibits smaller Pt particle size, greater Pt dispersion, larger specific electrochemically active surface area (ECSA), higher activity for MOR and ORR, and better electrocatalytic stability than the carbon black (Vulcan XC-72R)-supported Pt and commercial Pt/C catalysts.
Although various
bio-inspired materials with outstanding mechanical, acoustic, and
optic properties have been developed, bio-inspired materials for microwave
absorption applications are rarely reported. Herein, under the inspiration
of the opal structure, for the first time, a kind of Co@Co3O4/nitrogen-doped (N-doped) mesoporous carbon sphere (Co@Co3O4/NMCS) with a periodic three-dimensional structure
toward microwave absorption application was designed and synthesized.
The microwave absorption performance was optimized with respect to
the content of Co@Co3O4 nanoparticles. Co@Co3O4/NMCS with ∼20 wt % Co@Co3O4 achieves a reflection loss of −53.8 dB at 5.7 GHz.
The simulated radar cross section demonstrated that the Co@Co3O4/NMCS can efficiently suppress the strong electromagnetic
scattering from a metal groove structure, which further reveals its
excellent absorbing performance. These periodic porous structures
of N-doped mesoporous carbon spheres combined with the magnetic Co@Co3O4 nanoparticles contribute to the excellent microwave-absorbing
performance.
Tumor growth and metastasis are angiogenesis dependent. Angiogenic growth involves endothelial cell proliferation, migration, and invasion. Ephrin-B2 is a ligand for Eph receptor tyrosine kinases and is an important mediator in vascular endothelial growth factor-mediated angiogenesis. However, research offer controversial information regarding effects of ephrin-B2 on vascular endothelial cells. In this paper, proteome analyses showed that ephrin-B2/Fc significantly activates multiple signaling pathways related to cell proliferation, survival, and migration and suppresses apoptosis and cell death. Cytological experiments further confirm that ephrin-B2/Fc stimulates endothelial cell proliferation, triggers dose-dependent migration, and suppresses cell apoptosis. Results demonstrate that soluble dose-dependent ephrinB2 can promote proliferation and migration and inhibit apoptosis of human umbilical vein endothelial cells. These results also suggest that ephrinB2 prevents ischemic disease and can potentially be a new therapeutic target for treating angiogenesis-related diseases and tumors.
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