MicroRNAs (miRNAs) are endogenous non-coding small RNA molecules that can be secreted into the circulation and exist in remarkably stable forms. Like intercellular miRNAs, circulating miRNAs participate in numerous regulations of biological process and expressed aberrantly under abnormal or pathological status. The quality and quantity changes of circulating miRNAs are associated with the initiation and progression of cancer and can be easily detected by basic molecular biology techniques. Consequently, considerable effort has been devoted to identify suitable extracellular miRNAs for noninvasive biomarkers in cancer. However, several challenges need to be overcome before the practical application. In this review, we discuss several issues of circulating miRNAs: biological function and basic transport carriers; extracellular cell communication process; roles as reliable cancer biomarkers and usage in targeted cancer therapy; and challenges for clinical application.

In this article, a coupled three-dimensional mathematic model is established to describe electromagnetic field, fluid flow, heat transfer and solidification in a round bloom continuous casting mold with electromagnetic stirring (M-EMS). The interaction between the induced flow and the impinging jet from a straight-through submerged entry nozzle (SEN) of the caster is numerically analyzed. The results show that the electromagnetic force appears to be circinate at the cross section of the round bloom. Moreover, the flow of the melt is characterized by a dominant swirling movement along the azimuthal direction in the horizontal plane with M-EMS. However, the swirl flow velocity decreases remarkably when solidification is taken into account. With the increase of stirring intensity, the steady flow becomes unstable accompanying with the bias flow, and the temperature distribution is unsymmetrical in the mold. The significant swirl flow with M-EMS prevents the superheated jet moving downward and weakens the invasion depth of the jet, and thus the location of the hot zone in the mold moves up evidently.

Amorphization of the support in single‐atom catalysts is a less researched concept for promoting catalytic kinetics through modulating the metal–support interaction (MSI). We modeled single‐atom ruthenium (RuSAs) supported on amorphous cobalt/nickel (oxy)hydroxide (Ru‐a‐CoNi) to explore the favorable MSI between RuSAs and the amorphous skeleton for the alkaline hydrogen evolution reaction (HER). Differing from the usual crystal counterpart (Ru‐c‐CoNi), the electrons on RuSAs are facilitated to exchange among local configurations (Ru‐O‐Co/Ni) of Ru‐a‐CoNi since the flexibly amorphous configuration induces the possible d–d electron transfer and medium‐to‐long range p–π orbital coupling, further intensifying the MSI. This embodies Ru‐a‐CoNi with enhanced water dissociation, alleviated oxophilicity, and rapid hydrogen migration, which results in superior durability and HER activity of Ru‐a‐CoNi, wherein only 15 mV can deliver 10 mA cm−2, significantly lower than the 58 mV required by Ru‐c‐CoNi.

Vegetation plays an important role in improving and restoring fragile ecological environments. In the Antaibao opencast coal mine, located in a loess area, the eco-environment has been substantially disturbed by mining activities, and the relationship between the vegetation and environmental factors is not very clear. Therefore, it is crucial to understand the effects of soil and topographic factors on vegetation restoration to improve the fragile ecosystems of damaged land. An investigation of the soil, topography and vegetation in 50 reclamation sample plots in Shanxi Pingshuo Antaibao opencast coal mine dumps was performed. Statistical analyses in this study included one-way ANOVA and significance testing using SPSS 20.0, and multivariate techniques of detrended correspondence analysis (DCA) and redundancy analysis (RDA) using CANOCO 4.5. The RDA revealed the environmental factors that affected vegetation restoration. Various vegetation and soil variables were significantly correlated. The available K and rock content were good explanatory variables, and they were positively correlated with tree volume. The effects of the soil factors on vegetation restoration were higher than those of the topographic factors.