Sequential Reassortments Underlie Diverse Influenza H7N9 Genotypes in China

Initial genetic characterizations have suggested that the influenza A (H7N9) viruses responsible for the current outbreak in China are novel reassortants. However, little is known about the pathways of their evolution and, in particular, the generation of diverse viral genotypes. Here we report an in-depth evolutionary analysis of whole-genome sequence data of 45 H7N9 and 42 H9N2 viruses isolated from humans, poultry, and wild birds during recent influenza surveillance efforts in China. Our analysis shows that the H7N9 viruses were generated by at least two steps of sequential reassortments involving distinct H9N2 donor viruses in different hosts. The first reassortment likely occurred in wild birds and the second in domestic birds in east China in early 2012. Our study identifies the pathways for the generation of diverse H7N9 genotypes in China and highlights the importance of monitoring multiple sources for effective surveillance of potential influenza outbreaks.National Natural Science Foundation (China) (31125016)National Natural Science Foundation (China) (31371338)National Center for Biotechnology Information (U.S.) (Major National Earmark Project for Infectious Diseases, 2013ZX10004611-002)National Basic Research Program of China (973 Program)National Basic Research Program of China (973 Program, grant, 2009CB918503)National Science and Technology Major Projects (2012ZX10004214001002)Jiangsu Sheng (China) (Priority Academic Program Development of Jiangsu Higher Education Institutions)National Natural Science Foundation (China) (31100950)MIT International Science and Technology Initiative

Application of Zn<i>_1−x</i>Cd<i>_x</i>S Photocatalyst for Degradation of 2-CP and TC, Catalytic Mechanism

Zn1−xCdxS catalysts with Zeolitic Imidazolate Framework-8 (ZIF-8) as the precursor were successfully prepared by ion exchange method, and the ability and electrochemical properties of a series of ZIF-8, ZnS and Zn1−xCdxS catalysts in photocatalytic degradation of 2-CP and TC were investigated. Doping of Cd ions was able to modulate the ZnS band gap width and improve the utilization of visible light by the photocatalyst. The nanocage catalysts with hollow structure of Zn1−xCdxS have better photocatalytic response. The removal of photocatalytic pollutants was up to 90% under optimal conditions. Using a Peroxymonosulfate (PMS)-assisted system to improve the degradation efficiency of 2-chlorophenol and tetracycline hydrochloride under visible light, we present a possible mechanism of Zn1−xCdxS as a photocatalyst for degradation in persistent pollutants and in PMS-assisted photocatalysis. Four active species, O2−, h+, -OH, and SO4•−, can be generated to degrade 2-chlorophenol and tetracycline hydrochloride under PMS-assisted activation. Zn1−xCdxS nanocage with high activity and stability provides a feasible approach to catalytically remove persistent pollutants from aqueous solutions under visible light conditions

Lasing properties and carrier dynamics of CsPbBr3 perovskite nanocrystal vertical-cavity surface-emitting laser

All-inorganic lead halide perovskite nanocrystals (NCs) have been widely investigated as highly promising optical gain materials due to their compelling electrical and optical properties. Although many efforts have been carried out, a deep understanding of perovskite NC vertical-cavity surface-emitting lasers (VCSELs) is elusive, which is very important in the development of photoelectronic integrated circuits. Along these lines, in this work, a low lasing threshold (22 μJ/cm2) single-mode VCSEL consisting of CsPbBr3 NCs film and two distributed Bragg reflectors was successfully constructed. The CsPbBr3 NCs were synthesized by using the supersaturated recrystallization method. Interestingly, benefiting from the strong coupling between the active layer and the optical field in the cavity, a single-mode lasing at 527 nm was demonstrated under femtosecond optical pumping. The carrier dynamics of the perovskite NC VCSEL was also thoroughly investigated by performing pump intensity-dependent time-resolved photoluminescence measurements. The typical gain-switching phenomenon was observed with an ultrafast decay of the laser pulse of ∼10 ps. Our work provides valuable insights for the implementation of the CsPbBr3 NC VCSEL for various optoelectronic applications