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A newly isolated Rhodococcus sp. strain p52 could aerobically utilize dibenzofuran as the sole source of carbon and energy, and completely remove dibenzofuran at 500 mg l(-1) within 48 h. The strain metabolizes dibenzofuran by initial angular dioxygenation to yield 2,2',3-trihydroxybiphenyl. Strain p52 could also remove 70 % of 100 mg l(-1) 2-chlorodibenzofuran within 96 h and could metabolize a variety of aromatic compounds, namely dibenzo-p-dioxin, 2,8-dichlorodibenzofuran, dibenzothiophene, biphenyl, naphthalene, fluorene, phenanthrene, anthracene, carbazole, indole, xanthene, phenoxathiin, xanthone, and 9-fluorenone. Two distinct gene clusters encoding angular dioxygenases (DbfA and DfdA) were amplified and sequenced. The dbfA and dfdA gene clusters are located on two circular plasmids, pDF01 and pDF02, respectively. Both plasmids are self-transmissible; that is, they can transfer to the Gram-positive bacterium Bacillus cereus by conjugation.

The purpose of saliency detection is to detect significant regions in the image. Great progress on salient object detection has been made using from deep-learning frameworks. How to effectively extract and integrate multiscale information with different depths is an open problem for salient object detection. In this paper, we propose a processing mechanism based on a balanced attention module and interactive residual module. The mechanism addressed the acquisition of the multiscale features by capturing shallow and deep context information. For effective information fusion, a modified bi-directional propagation strategy was adopted. Finally, we used the fused multiscale information to predict saliency features, which were combined to generate the final saliency maps. The experimental results on five benchmark datasets show that the method is on a par with the state of the art for image saliency datasets, especially on the PASCAL-S datasets, where the MAE reaches 0.092, and on the DUT-OMROM datasets, where the F-measure reaches 0.763.

Genetic bioaugmentation, in which bacteria harboring conjugative plasmids provide catabolic functions, is a promising strategy to restore dioxin-contaminated environments. Here we examined the conjugative transfer of the dioxin-catabolic plasmids pDF01 and pDF02 harbored by Rhodococcus sp. strain p52. A mating experiment using strain p52 as a donor showed that pDF01 and pDF02 were concomitantly and conjugatively transferred from strain p52 to a Pseudomonas aeruginosa recipient at a conjugation frequency of 3 × 10 colonies per recipient. pDF01 and pDF02 were isolated from the P. aeruginosa transconjugant and identified by Southern hybridization, and they were localized in the transconjugant cells by fluorescence in situ hybridization. Moreover, the catabolic plasmids functioned in the transconjugant, which gained the ability to use dibenzofuran and chlorodibenzofuran for growth, and they were maintained in 50% of the transconjugant cells for 30 generations without selective pressure. Furthermore, conjugative transfer of the catabolic plasmids to activated sludge bacteria was detected. Sequencing of pDF01 and pDF02 revealed the genetic basis for the plasmids' conjugative transfer and stable maintenance, as well as their cooperation during dioxin catabolism. Therefore, strain p52 harboring pDF01 and pDF02 has potential for genetic bioaugmentation in dioxin-contaminated environments.

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Designing shape-controlled Pt-based core–shell nanocrystals is a prospective strategy to maximize the utilization of Pt while maintaining high activity for oxygen reduction reaction (ORR). However, the core–shell structures with ultrathin Pt shell exhibit limited electrochemical durability. Therefore, a thicker shell is proposed to successfully improve the durability of the core–shell structures by preventing the core from dissolution. Nevertheless, the deposition of Pt tends to switch to the Stranski–Krastanov (S–K) growth mode with the increase of the number of layer, resulting in the absence of a conformal morphology. Herein, we realize the deposition of three-to-five-layer epitaxial Pt–Co layers on Pd octahedral seeds by introducing tensile strain in the epitaxial layer to impede the S–K growth. The as-obtained Pd@Pt-Co octahedra with four layers exhibit enhanced mass activity (0.69 A/mgPt) and specific activity (1.00 mA/cm2) for ORR, which are 4.93 and 5 times that of the commercial Pt/C, respectively. Furthermore, it shows only 17% decay for specific activity after a 30,000-cycle durability test. This work is expected to enlighten the design and synthesis of related core–shell nanocrystals with facetted multicomponent shells, offering a promising strategy for designing cost-effective and efficient catalysts.

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