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Abstract The effects of sampling frequency on the efficacy of the POD technique for reconstructing the flow field of a wind turbine wake are studied in a neutral atmospheric boundary layer (ABL) using large eddy simulations (LES) coupled with an actuator disk model. The objective of this paper is to study how the sampling frequency over a fixed period of time affects the POD modes. The results showed that sampling frequency has little influence on the convergence of POD modes and the extraction of large‐scale coherent structures. Meanwhile, sampling frequency has negligible influence on the kinetic energy contained in each mode of the first 25 modes. When the mode number is greater than 25, it affects the distributed energy in each mode and the accumulative energy in a given number of modes, and the accuracy of the reconstructed flow field. In present study, the flow field reconstructed using the smallest sampling frequency can be as accurate as that with the largest sampling frequency, while the former can save about 86% of the computational cost. For a given number of POD modes, a smaller sampling frequency may lead to more accurate flow field reconstruction. The sampling frequency mainly affects the small‐scale structures.

Abstract Early embryos undergo extensive epigenetic reprogramming to achieve gamete‐to‐embryo transition, which involves the loading and removal of histone variant H2A.Z on chromatin. However, how does H2A.Z regulate gene expression and histone modifications during preimplantation development remains unrevealed. Here, by using ultra‐low‐input native chromatin immunoprecipitation and sequencing, the genome‐wide distribution of H2A.Z is delineated in mouse oocytes and early embryos. These landscapes indicate that paternal H2A.Z is removed upon fertilization, followed by unbiased accumulation on parental genomes during zygotic genome activation (ZGA). Remarkably, H2A.Z exhibits hierarchical accumulation as different peak types at promoters: promoters with double H2A.Z peaks are colocalized with H3K4me3 and indicate transcriptional activation; promoters with a single H2A.Z peak are more likely to occupy bivalent marks (H3K4me3+H3K27me3) and indicate development gene suppression; promoters with no H2A.Z accumulation exhibit persisting gene silencing in early embryos. Moreover, H2A.Z depletion changes the enrichment of histone modifications and RNA polymerase II binding at promoters, resulting in abnormal gene expression and developmental arrest during lineage commitment. Furthermore, similar transcription and accumulation patterns between mouse and porcine embryos indicate that a dual role of H2A.Z in regulating the epigenome required for proper gene expression is conserved during mammalian preimplantation development.

Platelets are implicated in the pathophysiology of breast and other cancers through their role in exchanging biomolecules with tumor cells in the tumor microenvironment. Such exchange results in tumor‐educated platelets with altered RNA expression profiles. Multiple lines of evidence indicate that platelet RNA profiles may be suitable as diagnostic biomarkers for cancer‐related biological processes. In this study, we characterized the gene expression signatures of platelets in breast cancer (BC) by high‐throughput sequencing and quantitative real‐time RT‐PCR. Our results indicate that the expression of TPM3 (tropomyosin 3) mRNA is significantly elevated in platelets from patients with BC compared with age‐matched healthy control subjects. Furthermore, up‐regulation of TPM3 mRNA in platelets was found to be significantly correlated with metastasis in patients with BC. Finally, we report that platelet TPM3 mRNA is delivered into BC cells through microvesicles and leads to enhanced migrative phenotype of BC cells. In summary, our findings suggest that the transfer of platelet TPM3 mRNA into cancer cells via microvesicles promotes cancer cell migration, and thus platelet‐derived TPM3 mRNA may be a suitable biomarker for early diagnosis of metastatic BC.

Lung cancer is the leading cause of cancer‐related morbidity and mortality worldwide, with lung adenocarcinoma (LUAD) being the most common histological subtype (approximately 40%). In the absence of reliable screening biomarkers for early diagnosis, most patients with LUAD are inevitably diagnosed at an advanced stage. MicroRNAs (miRNAs) encapsulated within plasma‐derived extracellular vesicles (EVs) may be suitable for use as noninvasive diagnostic biomarkers for aggressive malignancies, including LUAD. In this study, we first investigated the miRNA profiles of plasma‐derived EVs from LUAD patients and healthy donors, and then systematically evaluated the expression patterns of selected plasma‐derived EV miRNAs in a large cohort of patients with LUAD and healthy controls. Notably, we observed that miR‐451a, miR‐194‐5p, and miR‐486‐5p were significantly increased in EVs from LUAD patients, compared to healthy controls. The area under the curve values for the three miRNAs were 0.9040 (95% confidence interval [CI], 0.8633–0.9447) for miR‐451a, 0.7492 (95% CI, 0.6992–0.7992) for miR‐194‐5p, and 0.9574 (95% CI, 0.9378–0.9769) for miR‐486‐5p, while the AUC of the combination of these three miRNAs was 0.9650. Thus, these results suggest that these EV miRNAs may be promising candidates for the development of highly effective, noninvasive biomarkers for early LUAD diagnosis.

Abstract Studies regarding the reuse of a gob‐side roadway formed by the N00 longwall mining method are scarce. To investigate the mine pressure behavior characteristics during roadway reuse, the anchor cable force, roof‐to‐floor deformation, and working resistance of the hydraulic support obtained from the verification working face were analyzed. Test results show that the influence range of the mining‐induced pressure was 0‐90 m in front of the working face. The ratios of the first and periodic weighting steps between the entry‐retaining and non‐roof‐cutting sides were 20.25 and 1.94, respectively. However, the ratios of the ground pressure strengths at the two sides were 1.07 and 1.31, respectively. The results indicate that the monitored roadway can be classified into three deformation zones based on the severity of the mine pressure behavior: large, intermediate, and creep. The main roof between the adjacent working faces exhibited a failure type comprising the “O‐X” and “O‐Y” states, which resulted in an unconventional mine pressure behavior. This study provides insights into the N00 longwall mining method as well as important guidance for tackling similar geological conditions when using this mining method.

Abstract Nonpillar mining (NPM) with an automatically formed roadway is an emerging mining technology that does not use coal pillar retention and drivage. This technology can be used to actively control the caving height of the roof by directional cutting technology and can promote the rapid equilibrium of a fractured high roof under the support of the caved gangue. Therefore, when analyzing the stability of a high roof under NPM, not only the interaction force of the fractured rock blocks but also the effects of the support provided by the gangue, and the coal body should be considered. In addition, if necessary, the roof support in the roadway should also be considered. Based on this idea, in this paper, we analyzed the stability characteristics of a fractured high roof and suggested the stability conditions of the fractured rock of a high roof, including actual stability, pseudostability, and instability and provided the criteria for determining these three stability conditions. Furthermore, a visualized approach for the determination of roof stability was proposed. The core idea of the proposed approach is to transform the parameters that cannot be measured in the abovementioned conditions into visualized data that can be directly or indirectly obtained in the field, allowing for the detection and occasional assessment of the stability condition of the fractured rock of a high roof. This visualized determination approach can be used to assess the roof stability condition in a timely manner during the production process and to ensure production safety. The abovementioned research results were successfully used in the S1201‐II mining face of the Ningtiaota Coal Mine, indicating that the proposed approach is feasible and can be used under similar conditions.

The key block of the basic roof is the main contributor to the structural stability of a roadway. Research on the stability of the key block structure is of great significance for the promotion of noncoal pillar mining with automatically formed gob-side entry (GEFANM) technology. This paper is set in the engineering context of the GEFANM experiment at the Ningtiaota Coal Mine. The study fully considered the differences in the gob roof caving on the roof-cutting-line side, and the range of rotation angles to maintain a stable key block was determined. Based on this range of rotation angles, the range of safe bulking coefficients of gangue was calculated. The bulking coefficient of the gangue on the gravel side of the roadway was used as the metric in a new monitoring method and in the calculation of the field parameters. The range of safe bulking coefficients was determined to be 1.40–1.37. Field monitoring was conducted to obtain the gangue bulking coefficient on the gravel side. Combining the roof and floor convergence data, when the bulking coefficient fell within the safe range, the convergence was 95–113 mm. In this stage, the key block structure was stable. When the gangue bulking coefficient fell outside the safe range, the convergence was larger, and cracks were observed. The key block may be vulnerable to instability. The results affirmed that the gangue bulking coefficient can be used as a monitoring metric to study the stability of key block structures.