Performance and kinetics of rotating drum biofilter aerobic simultaneous purifying SO2 and NOx.

The rotating drum biofilter (RDB) was investigated as a biological process for purifying SO2 and NOx. After 25 days of film hanging, the inlet concentration was less than 2800 mg·m-3, and the NOx inlet concentration was less than 800 mg·m-3, with greater than 90% desulphurisation and denitration efficiency. Bacteroidetes and Chloroflexi were the dominant bacteria in desulphurisation, while Proteobacteria were the dominant bacteria in denitrification. The sulphur and nitrogen in RDB were balanced when the SO2 inlet concentration was 1200 mg·m-3 and the NOx inlet concentration was 1000 mg·m-3. The best results were obtained SO2-S removal load was 28.12 mg·L-1·h-1 and NOx-N removal load was 9.78 mg·L-1·h-1. when SO2 concentration was 1200 mg·m-3, NOx concentration was 800 mg·m-3, and empty bed retention time (EBRT) was 75.36 s. The liquid phase dominated the SO2 purification process, and the experimental data fit better with the liquid phase mass transfer model. NOx purification was governed by the biological and liquid phases, with the modified biological-liquid phase mass transfer model fitting the experimental data better.

Preliminary studies on the different roles of T6SSs in pathogenicity of Pseudomonas plecoglossicida NB2011.

Pseudomonas plecoglossicida, the causative agent of visceral granulomas in the large yellow croaker (Larimichthys crocea) in China, encodes three sets of type Ⅵ secretion systems (T6SS1-3). The purpose of this study was to characterize the different roles of T6SSs involved in infection. In-frame deletion of T6SSs was constructed, which resulted in 8 mutants. Competition against E. coli DH5α, virulence against the croaker and in vivo survival ability of the mutants were tested. The expression and secretion of Hcp by P. plecoglossicida NB2011 were investigated. The results showed T6SS2 mutant failed to inhibit the growth of E. coli, which is an indication of T6SS2 acting against environmental bacteria. The LD50 value of T6SS1 mutant strongly increased; T6SS2 and T6SS3 mutants were similar to that of the wild type; and the virulence of double deletion or triple deletion mutant was drastically alleviated, indicating that T6SS1 being one of the major virulence factors, and T6SS2 and T6SS3 directly or indirectly being involved in the pathogenicity. T6SS1 mutant disappeared in the fish spleen in 3 days, while other strains kept increasing, indicating the T6SS1 stimulation bacteria replication in vivo. Hcp1 secreted at 12-28°C and Hcp2 secreted at 12-35°C, while Hcp3 secretion not detected in vitro. This study has thrown some insights on the understanding of pathogenicity mechanisms of this pathogen.

A novel and fast responsive turn-on fluorescent probe for the highly selective detection of Cd2+ based on photo-induced electron transfer.

A novel, highly sensitive and fast responsive turn-on fluorescence probe, 2,2'-((1E,1'E)-((1,10-phenanthroline-2,9-diyl)bis(methanylylidene)) bis(azanylylidene)) diphenol (ADMPA), for Cd2+ was successfully developed based on 2,9-dimethyl-1,10-phenanthroline and o-aminophenol. ADMPA showed a remarkable fluorescence enhancement toward Cd2+ against other competing cations, owing to the suppression of the photo-induced electron transfer (PET) and CH[double bond, length as m-dash]N isomerization. A good linear relationship (R 2 = 0.9960) was obtained between the emission intensity of ADMPA and the concentration of Cd2+ (0.25-2.5 µM) with a detection limit of 29.3 nM, which was much lower than that reported in literature. The binding stoichiometry between ADMPA and Cd2+ was 2 : 1 as confirmed by the Job's Plot method, which was further confirmed by a 1H NMR titration experiment. Moreover, the ADMPA probe was successfully applied to detect Cd2+ in real water samples with a quick response time of only 6.6 s, which was about 3-40 times faster than the reported cadmium ion probe.