Damage detection of concrete under static loading based on ultrasonic sensor

In this paper, an ultrasonic sensor for concrete damage detection was designed and prepared. The ultrasonic sensor was used to detect concrete under static load. The results show that the piezoelectric sensor has high sensitivity when the resonant frequency of piezoelectric ceramic is 112kHz and the thickness of alumina matching layer is 1.5mm. As the concrete load increases gradually, the waveform moves backward, and the time for the sensor to receive the waveform becomes longer and the propagation speed becomes slower. When the load force on the concrete test block is small, peak-to-peak value and first wave amplitude decrease rapidly, while the loading force increases, and the decreasing amplitude gradually decreases. The peak-to-peak value decreases from 8.432V before loading to 1.289V when the loading force is 110kN, and the first wave amplitude decreases from 0.045V to 0.01V, proving that at this time, large damage has occurred in the concrete

Genetic diversity of eight wild populations of Pampus argenteus along the coast of China inferred from fifteen polymorphic microsatellite markers

Pampus argenteus (Perciformes: Stromateidae) is widely distributed along the coast of China, Indian Ocean, Arabian Gulf and North Sea. Due to overfishing and environmental degradation, its resources reduced year after year. Thus, new management strategies are urgently needed for the sustainable growth and utilization of this species. Characterization of the genetic variation of this fish species is essential for conserving the genetic resource and restraining the population decline. Therefore, it is necessary to have a clear understanding of the intraspecific genetic diversity and population structure of the species. In this study, we assess the genetic diversity and population structure of P. argenteus by using microsatellites. We genotyped 240 P. argenteus individuals from eight wild populations collected from Shidao (SD), Lianyungang (LYG), Lvsi (LS), Zhoushan (ZS), Dongtou (DT), Xiapu (XP), Haikou (HK), and Beibuwan (BBW) along the coast of China using fifteen polymorphic microsatellites. A total of 139 alleles were determined at 15 loci across the eight populations, and a relatively high level of genetic diversity was observed, with observed heterozygosity (Ho) and expected heterozygosity (He) ranging from 0.100 to 1.000, and from 0.669 to 0.934 per locus-location combination, respectively. LS had the highest average allele (number of alleles, A=15.200), and HK the lowest (A=13.000). Hos of P. argenteus are less than Hes, indicating lack of heterozygote within populations. Analysis of molecular variance (AMOVA) showed that most variation (95.66%) occurred within populations, suggesting that this is the main source of total variance. This study will provide useful information for conservation and sustainable exploitation of this important fishery resource

Role of Fra-2/AP-1 in Myogenic Progenitor Cells

Components of AP-1 have dynamic expression profiles during myogenesis in C2C12 cells, the expression profile of AP-1 is different among proliferative myoblasts, differentiating myoblasts, differentiated myotubes and reserve cells, indicating context-dependent spatial and temporal roles. We found that the expression profile of Fra-2/AP-1 is also dynamic in cultured single fibers, which harbor satellite cells. We observed Pax7 mRNA level went down accompanied with precocious differentiation upon konckdown of Fra-2, suggesting that Fra-2 may play a role in determining the fate of satellite cells by modifying the expression of the key specification factor, Pax7. In addition, inhibition of ERK 1/2 MAPK pathway, a known upstream kinase of Fra-2, led to the loss of Fra-2 and Pax7 expression at protein level. Furthermore, loss of function using siRNA technology indicated that the effect of AP-1 on Notch signaling and its downstream target genes in satellite cells is Fra-2 specific, while c-Jun did not have the same effect. Fra-2 was also found to modulate the expression of Sbno1, a novel downstream effector of Notch signaling in myogenic cells. In conclusion, this work provides some insight into the role of Fra-2/AP-1 in the regulation of satellite cells by looking into how Fra-2 might determine the fate of satellite cells by modulating the expression of Pax7

Recollements induced by left Frobenius pairs

Let $T$ be a right exact functor from an abelian category $\mathscr{B}$ into another abelian category $\mathscr{A}$. Then there exists an abelian category, named comma category and denoted by $(T\downarrow\mathscr{A})$.In this paper, we construct left Frobenius pairs (resp. strong left Frobenius pairs) over $(T\downarrow\mathscr{A})$ using left Frobenius pairs (resp. strong left Frobenius pairs) over $\mathscr{A}$ and $\mathscr{B}.$ As a consequence, we obtain a recollement of (right) triangulated categories, generalizing the result of Xiong-Zhang-Zhang (J. Algebra 503 (2018) 21-55) about the recollement of additive (resp. triangulated) categories constructed from a triangular matrix algebra. This result is applied to the classes of flat modules and Gorenstein flat modules, the classes of Gorenstein projective modules and Gorenstein projective complexes, the class of Ding projective modules and the class of Gorenstein flat-cotorsion modules.Comment: 24 pages, all comments are welcom