MicroRNAs (miRNAs) are small non-coding RNAs (typically consisting of 18–25 nucleotides) that negatively control expression of target genes at the post-transcriptional level. Owing to the biological significance of miRNAs, miRTarBase was developed to provide comprehensive information on experimentally validated miRNA–target interactions (MTIs). To date, the database has accumulated >13,404 validated MTIs from 11,021 articles from manual curations. In this update, a text-mining system was incorporated to enhance the recognition of MTI-related articles by adopting a scoring system. In addition, a variety of biological databases were integrated to provide information on the regulatory network of miRNAs and its expression in blood. Not only targets of miRNAs but also regulators of miRNAs are provided to users for investigating the up- and downstream regulations of miRNAs. Moreover, the number of MTIs with high-throughput experimental evidence increased remarkably (validated by CLIP-seq technology). In conclusion, these improvements promote the miRTarBase as one of the most comprehensively annotated and experimentally validated miRNA–target interaction databases. The updated version of miRTarBase is now available at http://miRTarBase.cuhk.edu.cn/.

A zinc oxide thin film in cubic crystalline phase, which is usually prepared under high pressure, has been grown on the MgO (001) substrate by a three-step growth using plasma-assisted molecular beam epitaxy. The cubic structure is confirmed by in-situ reflection high energy electron diffraction measurements and simulations. The x-ray photoelectron spectroscopy reveals that the outer-layer surface of the film (less than 5 nm thick) is of ZnO phase while the buffer layer above the substrate is of ZnMgO phase, which is further confirmed by the band edge transmissions at the wavelengths of about 390 nm and 280 nm, respectively. The x-ray diffraction exhibits no peaks related to wurtzite ZnO phase in the film. The cubic ZnO film is presumably considered to be of the rock-salt phase. This work suggests that the metastable cubic ZnO films, which are of applicational interest for p-type doping, can be epitaxially grown on the rock-salt substrates without the usually needed high pressure conditions.

Four new fluorenes bearing two electron donors and two electron acceptors were synthesized and found to emit blue fluorescence in both solution and solid states.

Square ZnO nano-columns have been manufactured by molecular beam epitaxy on p-type Si (100) substrate. The morphology and the evolution sequences after thermal annealing were investigated by in-situ scanning tunneling microscopy. We associated the morphology and microstructure evolution with the cubic Si (100) substrate, large lattice mismatching, the coexistence of wurtzite and zincblende phases of ZnO, and the thermal effect.ZnO, square nano-column, anneal, wurtzite phase, zincblende phase, Si (100) Citation:Huang B W, Zhan H H, Wu Y P, et al. Square ZnO nano-column and its thermal evolution.