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Mining rock masses in high-altitude cold regions can experience instability due to low temperature environments and dynamic load disturbances. Existing research mostly focuses on the static features of fractured sandstone under different freezing temperatures. Considering the influence of engineering excavation, further research is needed to investigate the mechanical and acoustic emission features of frozen fractured sandstone under dynamic loads. Therefore, a drop hammer impact test is conducted on frozen single fractured sandstone. The mechanical and acoustic emission features of frozen single fractured sandstone are analyzed using acoustic emission monitoring technology. The experimental results show the following points. ① An increase in the inclination angle of the crack will cause an increase in the rebound amplitude of the strain time curve before the peak strain. The crack will change from being distributed on both sides of the crack to being distributed on both ends of the crack. After the drop height of the hammer increases, the strain time curve shows a significant bimodal rebound before the strain peak, and the damage is significantly intensified. A decrease in freezing temperature will lead to an earlier onset of strain peak and an increase in strain peak. ② The propagation of microcracks has stage features, corresponding to strong microcracking activity at the peak strain and accompanied by intense energy release. ③ The activity of microcracking activity increases first and then decreases with the increase of inclination angle of the crack. The drop height of the hammer increases, and the intensity of microcracking activity gradually decreases. The decrease in freezing temperature leads to an earlier occurrence of microcracking activity. ④ Micro cracks are mainly tensile cracks, corresponding to macroscopic failure modes. ⑤ The sharp increase in entropy value is a precursor to sandstone failure and can be used as a warning indicator for dynamic instability of sandstone.

Seed cells and scaffold materials are essential components of tissue engineering. In this study, we investigated the key pathway of the zirconia/dental pulp stem cell composite scaffold in regulating macrophage polarization by transcriptome sequencing. We established N-rGO/ZrO2 composite scaffold and confirmed its structure using various analytical techniques, including SEM, TEM, FTIR, Raman spectra, XPS, and XRD. DPSCs were seeded onto N-rGO/ZrO2 composite scaffold material, and their proliferation, adhesion, and osteogenic differentiation were evaluated by CCK-8, immunofluorescence staining, ALP staining, and alizarin red staining. We then co-cultured DPSCs combined with N-rGO/ZrO2 as composite material with THP-1 cells in a transwell system to investigate the effect of the composite on macrophage polarization. The levels of pro-inflammatory (M1) and anti-inflammatory (M2) phenotypes were assessed by RT-qPCR and western blot. Through bulk RNA sequencing, we detected the transcriptional characteristics of macrophages under the regulation of the composite materials, and identified the differential genes using the DEseq2 package. We also analyzed the cellular and molecular functions of differentially expressed genes (DEGs) in THP-1 cells with DPSCs combined with N-rGO/ZrO2 treatment using GO enrichment analysis and KEGG pathway enrichment analysis. Our results showed that N-rGO/ZrO2 composite scaffold promoted the proliferation, adhesion, and osteogenic differentiation of DPSCs. Moreover, N-rGO/ZrO2 composite scaffold combined with DPSCs regulated macrophage migration, polarization, and glycolysis. Mechanistically, the combination of N-rGO/ZrO2 composite materials and DPSCs regulated macrophage polarization by activating the TNF signaling pathway. This finding provides a new approach to the clinical preservation of maxillofacial bone defect repair. [ABSTRACT FROM AUTHOR]

Wheat (Triticum aestivum L.) production is adversely impacted by Septoria nodorum blotch (SNB), a fungal disease caused by Parastagonospora nodorum. Wheat breeders are constantly up against this biotic challenge as they try to create resistant cultivars. The genome-wide association study (GWAS) has become an efficient tool for identifying molecular markers linked with SNB resistance. This technique is used to acquire an understanding of the genetic basis of resistance and to facilitate marker-assisted selection. In the current study, a total of 174 bread wheat accessions from South Asia and CIMMYT were assessed for SNB reactions at the seedling stage in three greenhouse experiments at CIMMYT, Mexico. The results indicated that 129 genotypes were resistant to SNB, 39 were moderately resistant, and only 6 were moderately susceptible. The Genotyping Illumina Infinium 15K Bead Chip was used, and 11,184 SNP markers were utilized to identify marker–trait associations (MTAs) after filtering. Multiple tests confirmed the existence of significant MTAs on chromosomes 5B, 5A, and 3D, and the ones at Tsn1 on 5B were the most stable and conferred the highest phenotypic variation. The resistant genotypes identified in this study could be cultivated in South Asian countries as a preventative measure against the spread of SNB. This work also identified molecular markers of SNB resistance that could be used in future wheat breeding projects. [ABSTRACT FROM AUTHOR]