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M & A was an important means to promote the transformation and upgrading of traditional industries, and also an important way to improve the degree of industrial concentration and speed up the transformation of industrial development mode. As a direct embodiment of the efficiency of M & A, the performance of M & A has been widely concerned by scholars. This paper introduced the concept of M & A performance and motivation of M & A, used Citespace to analyze 749 papers on M & A performance from CNKI core journals from 2000 to 2020,The research focus and frontier of M & A performance a analyzed by keyword clustering and keyword variation, and analyzed the research results of external environment, internal environment, M & A characteristics and external intermediary agencies which affect M & A performance, Finally, the possible direction of future research was proposed.

Perturbations to acoustic speech feedback have been typically localized to specific phonetic characteristics, for example, fundamental frequency (F0) or the first two formants (F1/F2), or affect all aspects of the speech signal equally, for example, via the addition of background noise. This paper examines the consequences of a more selective global perturbation: real-time cochlear implant (CI) simulation of acoustic speech feedback. Specifically, we examine the potential similarity between speakers’ response to noise vocoding and the characteristics of Lombard speech. An acoustic analysis of supra-segmental characteristics in speaking rate, F0 production, and voice amplitude revealed changes that paralleled the Lombard effect in some domains but not others. Two studies of speech intelligibility complemented the acoustic analysis, finding that intelligibility significantly decreased as a result of CI simulation of speaker feedback. Together, the results point to differences in speakers’ responses to these two superficially similar feedback manipulations. In both cases we see a complex, multi-faceted behavior on the part of talkers. We argue that more instances of global perturbation and broader response assessment are needed to determine whether such complexity is present in other feedback manipulations or if it represents a relatively rare exception to the typical compensatory feedback response. [ABSTRACT FROM AUTHOR]

Matrix metalloproteinase 26 (MMP-26) is a novel member of the matrix metalloproteinase (MMP) family and is widely expressed in cancer cells of epithelial origin. MMP-26 has been shown to contribute to tumor development and to the restoration of tissue injury. In this study, in order to identify the functions of MMP-26 that contribute to the biological phenotype and behavior of human lung carcinoma A549 cells, we established an MMP-26 low-expressing tumor cell model using RNA interference (RNAi) transfection. These cells were used to investigate the role of MMP-26 in tumor progression. The MTT, colony forming, adhere-nce and spreading, wound-healing and Transwell chamber invasion assays were performed to analyze the invasion ability of pshRNA-MMP26-transfected A549 cells. Semi-quantitative reverse transcription polymerase chain reaction, Western blotting and double immunofluorescent staining were employed to detect the relationship between MMP-26 and MMP-9. Results showed that the adhesive rate was down-regulated in pshRNA-MMP26-transfected cells, compared to the controls. Silencing of the MMP-26 gene significantly retarded the invasiveness of A549 cells in Transwell insert invasion assays. The cells proliferated in the three-dimensional (3D) culture system. A549 cells transfected with the pshRNA-MMP26-C plasmid mainly developed reticular structures in morphology, and formed few clones with clear and smooth edges as well as tight intercellular junctions. The mRNA and protein expression of MMP-9 in pshRNA-MMP26-transfected cells were significantly lower than those of the controls. Double immunofluorescence labeling and focal laser scanning microscopy showed that MMP-26 was colocalized with MMP-9 in the controls. In conclusion, we successfully established an MMP-26 low-expressing cell model and confirmed that MMP-26 contributed to A549 cell invasion and migration in vitro. We also demonstrated that MMP-26 plays an important role in local invasion at least in part through coordination with MMP-9.