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Graphene nanoflakes (GNFs), with intriguing zigzag edge magnetism, have great potential for the application in high-speed and low-power nanoelectronics and spintronics. However, scattering from edge defects can substantially degrade this novel edge magnetism. Precisely controlled growth of GNFs with zigzag edges on dielectric substrates to suppress edge defect scattering is still challenging. Herein, we report the successful synthesis of triangular zigzag-edged GNFs via epitaxy on hexagonal boron nitride (h -BN) templates. Further magnetic measurement results indicate the triangular zigzag-edged GNFs embedded in h -BN can induce the magnetization with a magnitude of 1e-4 emu/g at room temperature. Additionally, density functional theory calculations address such magnetic orderings originating from the superexchange interactions among local "unpaired" electrons located in the zigzag C−BN interface. Our in-plane hetero-integration approach to the template-epitaxial growth of GNFs on the pre-etched h -BN provides a promising platform for experimentally achieving GNFs with high electron spin states, which are highly desired for next-generation spintronics and nanoelectronics. [Display omitted] [ABSTRACT FROM AUTHOR]

Owing to its excellent properties in optical and electronic applications, twisted bilayer graphene (TBG) has attracted extensive research attention. As an encapsulation layer, hexagonal boron nitride (h -BN) is indispensable for fabricating TBG devices. Because h -BN and graphene exhibit similar lattice structures, TBG on h -BN exhibits periodic moiré patterns, which enable interlayer orientations to be revealed for bilayer graphene on h -BN. Herein, we used two-step chemical vapor deposition to synthesize TBG exhibiting multiple twist angles on h -BN. Conductive atomic force microscopy measurements revealed that the conductivity distribution was different for the graphene/ h -BN and TBG moiré patterns. Using the characteristics of the moiré patterns formed by these layers, h -BN and graphene interlayer orientations were precisely determined. This provides a feasible method for investigating the turbostratic arrangement of few-layer van der Waals heterostructures. [Display omitted] [ABSTRACT FROM AUTHOR]

Mucus overproduction is an important feature in patients with chronic inflammatory airway diseases and cold air stimulation has been shown to be associated with the severity of these diseases. However, the regulatory mechanisms that mediate excessive mucin production under cold stress remain elusive. Recently, the cold-inducible RNA-binding protein ( CIRP ) has been shown to be markedly induced after exposure to cold air. In this study, we sought to explore the expression of CIRP within bronchial biopsy specimens, the effect on mucin5AC (MUC5AC) production in chronic inflammatory airway diseases and the potential signaling pathways involved in cold air stimulation process. We found that CIRP protein expression was significantly increased in patients with COPD and in mice treated with cold air. Moreover, cold air stimulation induced MUC5AC expression in wild-type mice but not in CIRP −/− mice. In vitro, cold air stress significantly elevated the transcriptional and protein expression levels of MUC5AC in human bronchial epithelial cells. CIRP , toll-like receptor 4 (TLR4) and phosphorylated NF-κB p65 (p-p65) increased significantly in response to cold stress and CIRP siRNA, TLR4 - neutralizing Ab and a specific inhibitor of NF-κB could attenuated cold stress inducible MUC5AC expression. In addition, CIRP siRNA could hindered the expression levels of TLR4 and p-p65 both induced by cold stress. Taken together, these results suggest that airway epithelial cells constitutively express CIRP in vitro and in vivo. CIRP is responsible for cold-inducible MUC5AC expression by activating TLR4/NF-κB signaling pathway. [ABSTRACT FROM AUTHOR]

Abstract For graphene grown on Cu substrate via chemical vapor deposition (CVD), numerous nanometer particles are distributed along the graphene grain boundaries or evenly on the circumjacent substrate surface. The particles form new nucleation centers of graphene or destroy the graphene membrane during growth. In order to clarify the origin of particles, the formation process was studied by etching graphene at high temperature with different atmospheric pressures. We demonstrated that the formation of the particles is closely related to the competition of hydrogen and oxygen during growth; we also confirmed that the main component of particles was SiO x by energy dispersive spectrometry (EDS) measurement in transmission electron microscopy (TEM). Finally, on the basis of the formation mechanism, we proposed efficient approaches to reduce SiO x particles that improve the quality of graphene during actual CVD preparation process. Graphical abstract Image 1 Highlights • The formation mechanism of SiO x particles is closely related to the competition of hydrogen and oxygen impurity during graphene growth. • Hydrogen etches quartz to produce silicon, and then oxygen impurity react with silicon to produce SiO x particles in the case of hydrogen significantly reduced in the system. • The simplest and efficient measure to reduce SiO x particles is to avoid the sharp drop of hydrogen concentration during CVD. [ABSTRACT FROM AUTHOR]