Shexiang Baoxin Pill treats acute myocardial infarction by promoting angiogenesis via GDF15-TRPV4 signaling.

Angiogenesis has been considered a pivotal strategy for treating ischemic heart disease. One possible approach, the Shexiang Baoxin Pill (MUSKARDIA), has been noted to promote angiogenesis, but its underlying mechanism is still largely unknown. We aimed to determine the effects of MUSKARDIA on acute myocardial infarction (AMI), as well as the underlying mechanistic bases. AMI was induced in rats, using left anterior descending coronary arterial occlusion, and either 6 (low) or 12 (high-dose) mg/kg/day of MUSKARDIA was administered for 56 days. We found that MUSKARDIA improved cardiac function and counteracted against adverse remodeling among AMI rats, which most likely is due to it promoting angiogenesis. Transcriptome analysis by RNA-sequencing found that MUSKARDIA up-regulated cardiac pro-angiogenic genes, particularly growth differentiation factor 15 (GDF15), which was confirmed by RT-qPCR. This up-regulation was also correlated with elevated serum GDF15 levels. In vitro analyses with human umbilical vein endothelial cells found that increased GDF15, stimulated by MUSKARDIA, resulted in enhanced cell migration, proliferation, and tubular formation, all of which were reversed after GDF15 knockdown using a lentiviral vector. Gene Ontology, as well as Kyoto Genes and Genomes enrichment analyses identified calcium signaling pathway as a major contributor to these outcomes, which was verified by Western blot and Cal-590 AM loading showing that transient receptor potential cation channel subfamily V member 4 protein (TRPV4) and intracellular Ca2+ levels increased in accordance with MUSKARDIA-induced GDF15 up-regulation, and decreased with GDF15 knock-down. Therefore, MUSKARDIA may exert its cardioprotective effects via stimulating the GDF15/TRPV4/calcium signaling/angiogenesis axis.

Fracture Behavior of Steel Slag Powder-Cement-Based Concrete with Different Steel-Slag-Powder Replacement Ratios.

The influence of different replacement ratios of steel-slag powder as cement-replacement material on the fracture performance of concrete is studied in this paper. A three-point bending fracture test is carried out on slag powder-cement-based concrete (SPC)-notched beams with steel-slag powder as cementitious materials, partially replacing cement (0%, 5%, 10%, 15%, and 20%). Load-deflection curves and load-crack-opening displacement curves of SPC-notched beams with five different replacement ratios of steel-slag powder were obtained. The effects of different steel-slag-powder replacement ratios on the fracture properties (fracture energy, fracture toughness, and double-K fracture parameters) of the SPC were analyzed and discussed. The results showed that the incorporation of appropriate steel-slag powder can affect the fracture performance of SPC. Compared with concrete without steel-slag powder, adding appropriate steel-slag powder can effectively improve the bond performance between aggregate and matrix because the steel-slag powder contains hydration activity substances such as calcium oxide and aluminium trioxide. The fracture energy and fracture toughness of SPC increased and then decreased with the increase in steel-slag-powder replacement ratios, and the SPC concrete showed best fracture performance with a 5% steel slag powder replacement ratio. Its fracture energy increases by 13.63% and fracture toughness increases by 53.22% compared with NC.

Confined Concrete in Fiber-Reinforced Polymer Partially Wrapped Square Columns: Axial Compressive Behavior and Strain Distributions by a Particle Image Velocimetry Sensing Technique.

Strengthening existing reinforced concrete (RC) columns using a partial wrapping strengthening technique (PWST) by fiber-reinforced polymer (FRP) strips has been widely implemented. However, compared with the confinement mechanism of confined concrete in columns strengthened with the FRP full wrapping strengthening technique (FWST), the confinement mechanism of confined concrete in FRP partially wrapped columns is less understood. This paper presents the results of an experimental investigation into the behavior of confined concrete in FRP partially wrapped square columns under axial compression. The effects of FRP strip width and thickness on stress⁻strain behavior were thoroughly investigated. The novel particle image velocimetry (PIV) non-contact strain sensing technique was adopted to measure the strain in the specimens. Results show that the axial strains as well as the hoop strains are generally larger at the mid-plane of adjacent FRP strips than those at the mid-plane of each FRP strip, and considerable variation in hoop strains along the height of the specimens was observed. Comparisons between the experimental results and predictions by existing design-oriented stress⁻strain models were carried out to examine the accuracy of the models. A new design-oriented stress⁻strain model is proposed for confined concrete in FRP partially wrapped square columns and the comparisons between laboratory results and predictions from the proposed model show that the proposed model is superior to the existing models.