One hundred and thirty-six bla OXA-51-negative strains were identified from 1,067 Acinetobacter calcoaceticus-A. baumannii complex (ACB complex) isolates, which were collected during October 2010 to March 2013 from 15 general hospitals in 10 cities throughout Zhejiang Province, China. Seven of the 136 bla OXA-51-negative ACB complex isolates were New Delhi metallo-β-lactamase-1 (NDM-1)-positive, among which three were identified as A. nosocomialis and four were identified as A. pittii strains using 16S-23S rRNA gene intergenic spacer (ITS) sequencing and partial RNA polymerase β-subunit (rpoB) sequencing. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) analysis showed that the seven NDM-positive isolates belonged to three clonal strains with three novel sequence types (STs). Polymerase chain reaction (PCR) assays and DNA sequence analysis of the carbapenemase and other β-lactamase genes indicated that all the isolates harbored the bla NDM-1 gene, and that only one strain of A. nosocomialis isolates harbored both bla NDM-1 and bla OXA-23. All of them were positive for bla ADC, from which three novel bla ADC genes (designated as bla ADC-69, bla ADC-70, and bla ADC-71) were detected for the first time. The presence of ISAba125 upstream of bla NDM-1 was identified through genetic environment analysis. Carbapenem resistance can be transferred from A. nosocomialis and A. pittii to Escherichia coli EC600 by the conjugation experiment. Plasmid analysis, DNA hybridization, and extraction experiments indicated that bla NDM-1 was located on a plasmid of approximately 50 kb. In conclusion, we characterized the dissemination of NDM-1-positive A. pittii strains in Zhejiang Province, China, and reported the NDM-producing A. nosocomialis for the first time.

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The concurrent multiscale method, which couples the discrete element method (DEM) for predicting the local micro-scale evolution of the soil particle skeleton with the finite element method (FEM) for estimating the remaining macro-scale continuum deformation, is a versatile tool for modeling the failure process of soil masses. This paper presents the separate edge coupling method, which is degenerated from the generalized bridging domain method and is good at eliminating spurious reflections that are induced by coupling models of different scales, to capture the granular behavior in the domain of interest and to coarsen the mesh to save computational cost in the remaining domain. Cundall non-viscous damping was used as numerical damping to dissipate the kinetic energy for simulating static failure problems. The proposed coupled DEM-FEM scheme was adopted to model the wave propagation in a 1D steel bar, a soil slope because of the effect of a shallow foundation and a plane-strain cone penetration test (CPT). The numerical results show that the separate edge coupling method is effective when it is adopted for a problem with Cundall non-viscous damping; it qualitatively reproduces the failure process of the soil masses and is consistent with the full micro-scale discrete element model. Stress discontinuity is found in the coupling domain.Before the cone's penetration (s = 0.0 m), the distribution of the contact normal directions is heterogeneous because of gravity (most of the contact normals are near in y direction), which can also be observed from the force chains (contact normals and normal contact forces) in Figure 15. As the cone tip approaches the monitoring point (e.g., s = 0.25 m), the soil particles rotate because of the cone's disturbance, and most of the contact normal directions are 60°and 120°from the x axis Figure 14. Mesh and DE particles for different penetration depths: (a) s = 0.1 m; (b) s = 0.3 m; (c) s = 0.5 m. [Colour figure can be viewed at wileyonlinelibrary.com] Figure 16. Distributions of the contact normal directions at (0.71 m, 0.67 m): (a) s = 0.0 m; (b) s = 0.25 m; (c) s = 0.5 m. [Colour figure can be viewed at wileyonlinelibrary.com] Figure 17. Variation of the void ratio at (0.71 m, 0.67 m).Figure 18. Stress field σ y for different penetration depths: (a) 0 m, (b) 0.1 m, (c) 0.3 m and (d) 0.5 m. [Colour figure can be viewed at wileyonlinelibrary.com]

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