A Transmission Efficiency Evaluation Method of Adaptive Coding Modulation for Ka-Band Data-Transmission of LEO EO Satellites.

Nowadays low Earth orbit (LEO) Earth observation (EO) satellites commonly use constant coding modulation (CCM) or variable coding modulation (VCM) schemes for data transmission to ground stations (G/S). Compared with CCM and VCM, the adaptive coding modulation (ACM) could further improve the data throughput of the link by making full use of link resource and the time-varying characteristics of atmospheric attenuation. In order to comprehensively study the data transmission performance, one new index which could be utilized as a quantitative index for the satellite-to-ground data transmission scheme selection, the transmission efficiency factor (TEF) of LEO satellites is proposed and defined as "the product of the link availability and the average useful data rate". Then, the transmission efficiency of CCM, VCM and ACM at typical G/S with different weather characteristics at Ka-band is compared and analyzed. The results show that ACM is more suitable for the G/S with moderate and abundant rainfall. Compared with the CCM of MCS 28, for Beijing G/S and Sanya G/S, ACM not only improves the transmission efficiency with the TEF increased by 3.62% and 24.51%, respectively, but also improves the link availability with the outage period reduced by 82.47% and 75.18%, respectively.

[Effect of Porous Fillers Properties on Biofilm Growth].

As an important part of biological aerated filters (BAFs), porous fillers are key to the effectiveness of BAF wastewater treatment. At present, there are many types of fillers, but the influence of the surface physical and chemical properties on biofilm formation is unclear, and how to compare and select the best biological filler remains a difficult problem in BAF engineering applications. In this study, the physical and chemical characteristics of several porous biological fillers that are commonly used in BAFs were studied, and the correlation between their physical/chemical properties and the biofilm attachment and enzyme activity of the biofilm on the filler was investigated. The results showed that the sponge filler could easily absorb sludge, but also clogged easily and the overall biofilm activity was not high. The three-dimensional hollow filler had a low surface-adsorbed biomass, but the specific surface area was large and the surface attachment growth biofilm activity was relatively strong. Ceramsite had a good hydrophilicity and high surface roughness, and the zeta potential was the most positive. Moreover, microorganisms easily attached and grew, it had the strongest sludge adhesion performance, and the best biofilm activity. According to a redundancy analysis (RDA), the main factor affecting the biomass on the surface of the fillers was the zeta potential, whereas the main factors affecting the surface sludge activity of the fillers was the clearance rate. According to the removal load of NH4+-N by six groups of reactors, the removal load of NH4+-N by ceramsite was the largest [68 g·(m3·d)-1], and was followed by volcanic rocks [67 g·(m3·d)-1]. Combined with the above factors, ceramsite was determined to be the most suitable filler for BAF.

Microcystin-LR Degradation and Gene Regulation of Microcystin-Degrading Novosphingobium sp. THN1 at Different Carbon Concentrations.

The bacterium Novosphingobium sp. THN1 (THN1) is capable of degrading microcystin-LR (MC-LR). To study the ability of THN1 to degrade MC-LR and its possible mechanism(s) of regulation, we analyzed the effect of carbon concentrations on the degradation process. The MC-LR degradation rate peaked early and then declined during MC-LR biodegradation. Decreased levels of carbon in the medium caused the degradation peak to occur earlier. The expression of the functional gene mlrA, encoding a microcystinase, showed a similar trend to the MC-LR degradation rate at various carbon concentrations (r2 = 0.717, p < 0.05), suggesting that regulation of mlrA expression may play an important role in MC-LR degradation by THN1. The total bacterial biomass decreased when the carbon source was limited and did not correlate with the MC-LR degradation rate. Transcriptomic analysis showed that MC-LR degradation differentially regulated 62.16% (2597/4178) of THN1 genes. A considerable number of differentially expressed genes (DEGs) during MC-LR degradation encoded proteins related to carbon-, nitrogen-, and amino acid-related pathways. At 2 h of MC-LR degradation, most DEGs (29/33) involved in carbon and nitrogen metabolism were downregulated. This indicated that MC-LR may regulate carbon and nitrogen pathways of Novosphingobium sp. THN1. KEGG pathway analysis indicated that the upregulated DEGs during MC-LR degradation were mainly related to amino acid degradation and substrate metabolism pathways. Particularly, we detected increased expression of glutathione metabolism-related genes from transcriptomic data at 2 h of MC-LR degradation compared with the gene expression of 0 h, such as GST family protein, glutathione peroxidase, S-(hydroxymethyl) glutathione dehydrogenase, and glutathione-dependent disulfide-bond oxidoreductase that have been reported to be involved in microcystin degradation.

Green chemical synthesis of new chelating fiber and its mechanism for recovery gold from aqueous solution.

A novel environmentally-friendly polyacrylonitrile-2-amino-2-thiazoline chelating fiber (PANF-ATL) with good adsorption performance and thermal stability was synthesized in one step by nucleophilic addition reaction using water as a solvent. The optimum synthesis conditions for the chelating fibers are determined by controlling the synthesis temperature and the molar ratio of the reagents. The sulfur content and functional group capacity of the finally synthesized PANF-ATL were 3.82% and 1.19 mmol/g, respectively. PANF-ATL was characterized by elemental analysis, FTIR, TGA, SEM and XPS. Meanwhile, the adsorption characteristics and mechanism of PANF-ATL were evaluated. The Langmuir model and the pseudo-second-order model well described the adsorption of Au(Ⅲ) by PANF-ATL. The adsorption capacity of PANF-ATL obtained from Langmuir isotherm model towards Au(Ⅲ) was 130.58 mg/g (298 K). In addition, Au(Ⅲ) adsorbed on the fibers was completely eluted using a mixed solution of 4 mol/L HCl and 12% thiourea. It still has good adsorption performance after 5 adsorption-desorption cycles. Overall, PANF-ATL is a cost-effective adsorbent that can effectively adsorb Au(Ⅲ) in aqueous solution.

Comparative Genomics of Degradative Novosphingobium Strains With Special Reference to Microcystin-Degrading Novosphingobium sp. THN1.

Bacteria in genus Novosphingobium associated with biodegradation of substrates are prevalent in environments such as lakes, soil, sea, wood and sediments. To better understand the characteristics linked to their wide distribution and metabolic versatility, we report the whole genome sequence of Novosphingobium sp. THN1, a microcystin-degrading strain previously isolated by Jiang et al. (2011) from cyanobacteria-blooming water samples from Lake Taihu, China. We performed a genomic comparison analysis of Novosphingobium sp. THN1 with 21 other degradative Novosphingobium strains downloaded from GenBank. Phylogenetic trees were constructed using 16S rRNA genes, core genes, protein-coding sequences, and average nucleotide identity of whole genomes. Orthologous protein analysis showed that the 22 genomes contained 674 core genes and each strain contained a high proportion of distributed genes that are shared by a subset of strains. Inspection of their genomic plasticity revealed a high number of insertion sequence elements and genomic islands that were distributed on both chromosomes and plasmids. We also compared the predicted functional profiles of the Novosphingobium protein-coding genes. The flexible genes and all protein-coding genes produced the same heatmap clusters. The COG annotations were used to generate a dendrogram correlated with the compounds degraded. Furthermore, the metabolic profiles predicted from KEGG pathways showed that the majority of genes involved in central carbon metabolism, nitrogen, phosphate, sulfate metabolism, energy metabolism and cell mobility (above 62.5%) are located on chromosomes. Whereas, a great many of genes involved in degradation pathways (21-50%) are located on plasmids. The abundance and distribution of aromatics-degradative mono- and dioxygenases varied among 22 Novosphingoibum strains. Comparative analysis of the microcystin-degrading mlr gene cluster provided evidence for horizontal acquisition of this cluster. The Novosphingobium sp. THN1 genome sequence contained all the functional genes crucial for microcystin degradation and the mlr gene cluster shared high sequence similarity (≥85%) with the sequences of other microcystin-degrading genera isolated from cyanobacteria-blooming water. Our results indicate that Novosphingobium species have high genomic and functional plasticity, rearranging their genomes according to environment variations and shaping their metabolic profiles by the substrates they are exposed to, to better adapt to their environments.

Electrochemical oxidation of quinoline aqueous solution on ß-PbO2 anode and the evolution of phytotoxicity on duckweed.

Electrochemical oxidation of quinoline on a ß-PbO2 electrode modified with fluoride resin and the comprehensive toxicity of intermediates formed during oxidation on duckweed were investigated in detail. The results showed that quinoline was initially hydroxylated at the C-2 and C-8 positions by hydroxyl radicals (·OH) electro-generated on a ß-PbO2 anode, yielding 2(1H)-quinolinone and 8-hydroxyquinoline, then undergoing ring cleavage to form pyridine, nicotinic acid, pyridine-2-carboxaldehyde and acetophenone, which were ultimately converted to biodegradable organic acids. NO3- was the final form of quinoline-N. The growth of duckweed exposed to the oxidized quinoline solution was gradually inhibited with the decrease in pH and the formation of intermediates. However, the growth inhibition of duckweed could be eliminated beyond 120 min of oxidation, indicating the comprehensive toxicity of the quinoline solution reduced when the amount of quinoline removed was above 80%. Additionally, the adjustment of the pH to 7.5 and the addition of nutrients to the treated quinoline solution before culturing duckweed could obviously alleviate the inhibition on duckweed. Thus, partial electrochemical degradation of quinoline offers a cost-effective and clean alternative for pretreatment of wastewater containing nitrogen-heterocyclic compounds before biological treatment. The duckweed test presents a simple method for assessing the comprehensive toxicity of intermediates.

[Heavy metal pollution characteristics and ecological risk analysis for soil around Haining electroplating industrial park].

The pollution status and potential ecological risks of heavy metal in soils around Haining electroplating industrial park were studied. Hakanson index approach was used to assess the ecological hazards of heavy metals in soils. Results showed that average concentrations of six heavy metals (Cu, Ni, Pb, Zn, Cd and Cr) in the soils were lower than the secondary criteria of environmental quality standard for soils, indicating limited harmful effects on the plants and the environment in general. Though the average soil concentrations were low, heavy metal concentrations in six sampling points located at the side of road still exceeded the criteria, with excessive rate of 13%. Statistic analysis showed that concentrations of Cu and Cd in roadside soils were significantly higher than those in non-roadside soils, indicating that the excessive heavy metal accumulations in the soil closely related with traffic transport. The average potential ecological hazard index of soils around Haining electroplating industrial park was 46.6, suggesting a slightly ecological harm. However, the potential ecological hazard index of soils with excessive heavy metals was 220-278, suggesting the medium ecological hazards. Cd was the most seriously ecological hazard factor.