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Background:Aberrant Smad7 expression contributes to the invasion and metastasis of pancreatic cancer cells. However, the potential mechanism underlying aberrant Smad7 expression in human pancreatic ductal adenocarcinoma (PDAC) remains largely unknown.Methods:Bioinformatic prediction programmes and luciferase reporter assay were used to identify microRNAs regulating Smad7. The association between miR-367 expression and the overall survival of PDAC patients was evaluated by Kaplan–Meier analysis. The effects of miR-367 and Smad7 on the invasion and metastasis of pancreatic cancer cells were investigated both in vitro and in vivo.Results:We found that miR-367 downregulated Smad7 expression by directly targeting its 3′-UTR in human pancreatic cancer cells. High level of miR-367 expression correlated with poor prognosis of PDAC patients. Functional studies showed that miR-367 promoted pancreatic cancer invasion in vitro and metastasis in vivo through downregulating Smad7. In addition, we showed that miR-367 promoted epithelial-to-mesenchymal transition by increasing transforming growth factor-β (TGF-β)-induced transcriptional activity.Conclusions:The present study identified and characterised a signalling pathway, the miR-367/Smad7-TGF-β pathway, which is involved in the invasion and metastasis of pancreatic cancer cells. Our results suggest that miR-367 may be a promising therapeutic target for the treatment of human pancreatic cancer.

Selective area epitaxy has been used to grow pyramidal GaN stripes, followed by InGaN multiple quantum well (MQW) structures, in order to produce long-wavelength green light emission. Stripes oriented along ⟨112¯0⟩ produce smooth {11¯01} sidewall facets. The room-temperature optical properties are investigated by cathodoluminescence spectroscopy using a scanning electron microscope. MQWs grown in unmasked reference regions exhibit emission at 450 nm. The stripe sidewalls emit light with peak wavelength of 500 nm with consistent linewidth and intensity. The stripe ridge emits light with peak intensity at wavelength of ∼550 nm. Based on the spatial extent of the 550 nm emission, the ridge is estimated to be ∼250 nm wide. The large redshift is produced by the enhanced presence of indium species due to lateral vapor diffusion and surface migration in selective area epitaxy.

The growing integration of wind energy into power networks will have a significant impact on power system stability. With the development of Wind Turbine (WT) techniques, the Doubly Fed Induction Generator (DFIG) becomes the dominant WT type used in wind farms. In this situation, DFIG should be modeled properly in power system stability analysis. A detailed model of the WT with DFIG and its associated controllers is presented, based on which the small signal stability model is derived. Small signal stability analysis shows that the DFIG control can significantly improve the stability of WT system. Applying a set of optimized controller parameters, the stability can be further enhanced. Dynamic simulations are performed to illustrate the control performance.

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