16S rRNA Cloning and Identification of a Strain Isolated from Intestinal Tract of Rex Rabbit

This study was conducted to identify bacterial strain He Nan-001 isolated from intestinal tract of healthy rex rabbit.The strain was identified by gram staining,and OD_(600) values at different culture time were measured to develop a bacterial growth curve.The metabolic pathways of the bacterium using sugar in fermentation was identified with biochemical tubes.Total RNA of the strain was extracted,and total cDNA was obtained by Oligo(dT) method.Primers were designed using Primer 5.0 bio-software according to the 16S rRNA sequence published in Gen Bank,through cloning,ligation to vector PMD18T,construction of PMD18T/16S rRNA vector and transformation into DH5α,plasmid was extracted and sequenced,and the sequencing result was compared with sequences in NCBI followed by drawing of phylogenetic tree.The strain was verified to be double-stranded gram-positive cocci,which could ferment glucose,mannose,maltose and sorbitol,producing acids production,but failed to ferment sucrose,serum inulin and β-galactosidase.The phylogenetic tree analysis showed that the isolated bacterium shared the highest homology with an India isolate,and belongs to diplostreptococcus.This study provides significance experimental data and theoretical guidance for further development and utilization of the bacterial strain.

Heterostructure design of MOFs derived Co_(9)S_(8)/FeCoS_(2)/C composite with efficient microwave absorption and waterproof functions

At present, the problem of electromagnetic wave(EMW) pollution is critical, and the design of highperformance absorbers is of great significance. Based on the synergy between dielectric and magnetic losses, and between multicomponents in heterostructures, the development of light-weight absorbers with a strong absorption capability and multiple scattering is a promising strategy to achieve highperformance absorbers. In this work, CoFe-MOF precursors with a bouquet-like structure were prepared via the hydrothermal method, and Co_(7)Fe_(3)/C and Co_(9)S_(8)/FeCoS_(2)/C composites were obtained through a carbonization and sulfuration treatment during the high-temperature pyrolysis process, respectively. The experimental and theoretical results show that the Co_(9)S_(8)/FeCoS_(2)/C composite has a better EMW absorption performance, and its optimal reflection loss(RL) value is-53.9 d B at a low filler loading of 20 wt.%,which is due to the S doping that enhances the interface polarization relaxation process and improves the impedance matching characteristics. Moreover, the Co_(9)S_(8)/FeCoS_(2)/C composite can be as candidates of high-efficiency absorbers in extreme application environments.

Identification of the Exchange Coefficient from Indirect Data for a Coupled Continuum Pipe-Flow Model

Calibration and identification of the exchange effect between the karst aquifers and the underlying conduit network are important issues in order to gain a better understanding of these hydraulic systems. Based on a coupled continuum pipe-flow(CCPF for short) model describing flows in karst aquifers, this paper is devoted to the identification of an exchange rate function, which models the hydraulic interaction between the fissured volume(matrix) and the conduit, from the Neumann boundary data, i.e., matrix/conduit seepage velocity. The authors formulate this parameter identification problem as a nonlinear operator equation and prove the compactness of the forward mapping. The stable approximate solution is obtained by two classic iterative regularization methods, namely,the Landweber iteration and Levenberg-Marquardt method. Numerical examples on noisefree and noisy data shed light on the appropriateness of the proposed approaches.