Construction and Enhanced Efficiency of Bi2MoO6/ZnO Compo-Sites for Visible-Light-Driven Photocatalytic Performance.

Bi2MoO6 was one of the important bismuth-based semiconductors with a narrow bandgap, and has been widely used in selective oxidation catalysts, supercapacitors, and energy-storage devices. A series of Bi2MoO6/ZnO composite photocatalysts with different mass ratios were synthesized by the hydrothermal method. The synthesized samples were characterized by XRD, PL, UV-Vis, SEM, TEM, XPS, and BET analysis techniques. Under visible light conditions, Methylene blue (MB) was used as the target degradation product to evaluate its photocatalytic performance. The results showed that the degradation rate constant of Bi2MoO6/ZnO (0.4-BZO) was about twice that of the traditional photocatalysis of ZnO. The Bi2MoO6/ZnO composite catalyst maintained stable performance after four consecutive runs. The high photocatalytic activity of Bi2MoO6/ZnO was attributed to the efficient electron transport of the heterojunction, which accelerates the separation of electron-hole pairs and reduces the probability of carrier recombination near the Bi2MoO6/ZnO heterojunction. Bi2MoO6/ZnO nanocomposites have potential applications in the field of photodegradation.

Positive Selection Drove the Adaptation of Mitochondrial Genes to the Demands of Flight and High-Altitude Environments in Grasshoppers.

The molecular evolution of mitochondrial genes responds to changes in energy requirements and to high altitude adaptation in animals, but this has not been fully explored in invertebrates. The evolution of atmospheric oxygen content from high to low necessarily affects the energy requirements of insect movement. We examined 13 mitochondrial protein-coding genes (PCGs) of grasshoppers to test whether the adaptive evolution of genes involved in energy metabolism occurs in changes in atmospheric oxygen content and high altitude adaptation. Our molecular evolutionary analysis of the 13 PCGs in 15 species of flying grasshoppers and 13 related flightless grasshoppers indicated that, similar to previous studies, flightless grasshoppers have experienced relaxed selection. We found evidence of significant positive selection in the genes ATP8, COX3, ND2, ND4, ND4L, ND5, and ND6 in flying lineages. This results suggested that episodic positive selection allowed the mitochondrial genes of flying grasshoppers to adapt to increased energy demands during the continuous reduction of atmospheric oxygen content. Our analysis of five grasshopper endemic to the Tibetan Plateau and 13 non-Tibetan grasshoppers indicated that, due to positive selection, more non-synonymous nucleotide substitutions accumulated in Tibetan grasshoppers than in non-Tibetan grasshoppers. We also found evidence for significant positive selection in the genes ATP6, ND2, ND3, ND4, and ND5 in Tibetan lineages. Our results thus strongly suggest that, in grasshoppers, positive selection drives mitochondrial genes to better adapt both to the energy requirements of flight and to the high altitude of the Tibetan Plateau.

The complete mitochondrial genome of the jumping grasshopper Sinopodisma pieli (Orthoptera: Acrididae) and the phylogenetic analysis of Melanoplinae.

In this study, we reported the complete mitochondrial genome (mitogenome) of Sinopodisma pieli by polymerase chain reaction method for the first time, the type species of the genus Sinopodisma. Its mitogenome was a circular DNA molecule of 15,625 bp in length, with 76.0% A+T, and contained 13 protein-coding genes, 22 transfer RNA genes and two ribosomal RNA genes and one A+T control region. The overall base composition of the S. pieli mitogenome was 42.8% for A, 33.2% for T, 13.5% for C, and 10.5% for G, respectively. All 13 mitochondrial PCGs shared the start codon ATN. Twelve of the PCGs ended with termination codon TAA and TAG, while cytochrome coxidase subunit 1 (COI) utilized an incomplete T as terminator codon. All tRNA genes could be folded into the typical cloverleaf secondary structure, except trnS(AGN) lacking of dihydrouridine arm. The sizes of the large and small ribosomal RNA genes were 1379 bp and 794 bp, respectively. The A+T rich region was 798 bp in length and contained 88.5% AT content. A phylogenetic analysis based on 13 PCGs by using Bayesian inference (BI) and maximum likelihood (ML) revealed that Sinopodisma is not monophyletic group. We think that the name and taxonomic status of S. tsinlingensis are right, and it should not be moved into the genus Pedopodisma. These data will provide important information for a better understanding of the population genetics and species identification for Sinopodisma.

Recovery of SO2 and MgO from By-Products of MgO Wet Flue Gas Desulfurization.

An industrial demonstration unit using natural gas as a heat source was built to calcine the by-products of MgO wet flue gas desulfurization from power plants; influencing factors on the SO2 content in calciner gas were comprehensively analyzed; and an advantageous recycling condition of MgO and SO2 from by-products was summarized. Results showed that the SO2 content in the calciner gas was increased by more than 10 times under a lower excess air coefficient, a higher feed rate, a lower crystal water in by-products, and a higher feed port position. For the tests conducted under the excess air coefficient above and below one, the effect of the furnace temperature on the SO2 content in the calciner gas was reversed. Results of activity analysis indicate that particles of MgO generated under the calcination temperature of 900-1,000°C had a high activity. In contrast, due to the slight sintering, MgO generated under the calcination temperature of 1,100°C had a low activity. To recycle SO2 as well as MgO, a temperature range of 900-927°C for TE103 is proposed. These studies will prompt the desulfurization market diversification, reduce the sulfur's dependence on imports for making sulfuric acid, be meaningful to balance the usage of the natural resource in China, and be regarded as a reference for the development of this technology for other similar developing countries.