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In order to clarify the dust production law of railway tunnel drilling and blasting construction, the flow field structure characteristics and the distribution and migration law of drilling dust production in the tunnel under the condition of press-in ventilation were studied by indoor model test and CFD numerical simulation method. The results show that: 1) The dust concentration on the M axis and R axis gradually decreases with the increase of distance from the face of the face. The dust concentration on the L axis showed a small-large-small trend from the palm surface to the outlet of the hair dryer, and the maximum dust concentration appeared at 1m away from the face of the face. 2) Under the condition of press-in ventilation, the flow field structure can be divided into three parts: jet area, vortex area and reflux area, and the proportion of reflux gradually increases from 54% to 100% after three stages. 3) Large particles of dust mainly settle in the area of 1m from the end of the working face on the return air side, and the particle size of the dust settled on the tunnel floor gradually decreases with the increase of the distance from the face face; Most dust particles can settle or discharge the tunnel within 30s, and the vortex area has an adverse effect on the tunnel dust exhaust and dust reduction.

Aiming at the problem of detecting different sizes and types of ships in complex sea conditions, a ship detection method based on deep learning is proposed, which is mainly for the improvement of regional fully convolutional networks (R-FCN). Firstly, the ResNet50 network is selected for automatic extraction of features, and the feature map is automatically provided for the improved R-FCN. Secondly, the R-FCN is improved according to the characteristics of the ship identification, which allows the R-FCN to fully perform its performance on ship detection. Finally, according to the problem that the recognition rate of small ships in some categories is small, on the first step, the method of Maxpooling increases the recognition rate of small ships by 4.08 percentage points; on the second step, the improvement of ROIAlign makes the improved R-FCN in this paper perform much better on small target ship identification than original R-FCN, and the recognition rate is increased by 13 percentage points totally. This paper is also compared with the current mainstream target detection algorithms such as Faster-RCNN. Experimental results show that the method has higher recognition accuracy and the rate is basically the same as other methods.

To realize the aircraft maneuvering turn during ground operations, the aircraft’s nosewheel control system should provide the rate of nosewheel deflection as higher as possible. To prevent the aircraft’s wheel from lateral slip the deflection rate should be limited in a certain range. Take a certain type of aircraft as an example, the effect of lateral slip under the large nosewheel deflection, the friction coefficient on the ground, the aircraft taxiing speed and the rate of nose wheel deflection are analyzed. Results show that the aircraft makes large nosewheel deflection at the rate of 0.3~0.4 rad/s, it can basically meet the ground stability requirements, but to reduce the risk of lateral slip on the low friction pavement, the rate of nosewheel deflection needs to be reduced when the nose wheel deflects to a large angle.

The current study aimed to identify stable and interpretable profiles of 18,338 Chinese secondary school students in eighth grade on the basis of three aspects of reading engagement: behavioral, emotional, and cognitive engagement. Furthermore, the relationship between reading comprehension and these reading engagement profiles was investigated. Latent profile analysis revealed six groupings of individuals representing different patterns of the three aspects of reading engagement. These consistent patterns were labeled Large Amount/Strong Engagement (LA/SE) and Small Amount/Weak Engagement (SA/WE), respectively (0.50-1.75 SD above/below the mean), while the mixed patterns were labeled Large Amount/Moderate Engagement (LA/ME), Large Amount/Weak Engagement (LA/WE), Small Amount/Moderate Engagement (SA/ME), and Small Amount/Strong Engagement (SA/SE). The results (derived from the statistical analyses of consistent patterns) revealed that to some extent, the reading engagement profiles were linearly associated with reading comprehension. On the other hand, the mixed patterns suggest that the reading engagement profiles could be differentially associated with reading comprehension. The findings support the utility of exploring multidimensional reading engagement profiles in planning instruction to improve Chinese secondary school students' reading skills. Implications for reading instruction and research are discussed.

AbstractHigh HMGB1 levels contribute to the development and metastasis of tumors such as colorectal cancer (CRC). The current investigation sought to evaluate the association of a functional InDel polymorphism (rs34000982) on the HMGB1 gene with CRC susceptibility and tumor stage and the clinical relevance of HMGB1 gene expression. A total of 600 CRC patients and 600 healthy control individuals were genotyped by a polymerase chain reaction-polyacrylamide gel electrophoresis assay. The findings demonstrated that the rs34000982 Ins allele or Ins/Ins genotype was associated not only with reduced susceptibility to CRC, especially stage III-IV CRC (Ins vs. Del: OR = 0.65, 95%CI = 0.51-0.82, p < 0.001; Ins/Ins vs. Del/Del: OR = 0.29, 95%CI = 0.14- 0.60, p < 0.001), but also with tumor stage. CRC patients carrying the Ins allele or Ins/Ins genotype had a significantly lower risk of stage III-IV tumors (Ins vs. Del: OR = 0.69, 95%CI = 0.53- 0.91; Ins/Ins vs. Del/Del: OR = 0.41, 95%CI = 0.18-0.94). Functional research revealed that the rs34000982 Ins allele enabled hsa-miR-944 to interact with the 3’ untranslated region of HMGB1. In addition, HMGB1 gene expression levels were associated not only with multiple immune cell infiltration, but also with multiple anti-CRC drug sensitivities. The current findings suggest that the HMGB1 rs34000982 polymorphism may serve as a marker of CRC susceptibility and progression in the Chinese population, and HMGB1 levels may serve as an anti-CRC drug sensitivity marker. [ABSTRACT FROM AUTHOR]

The harmful effects of PM2.5 on human health, including an increased risk of chronic kidney disease (CKD), have raised a lot of attention, but the underlying mechanisms are unclear. We used the Shanghai Meteorological and Environmental Animal Exposure System (Shanghai-METAS) to simulate the inhalation of PM2.5 in the real environment and established an animal model by exposing C57BL/6 mice to filtered air (FA) and Particulate Matter (PM2.5) for 8 weeks. PM2.5 impaired the renal function of the mice, and the renal tubules underwent destructive changes. Analysis of NHANES data showed a correlation between reduced kidney function and higher blood levels of PM2.5 components, polychlorinated biphenyls (PCBs) and dioxins, which are Aryl hydrocarbon Receptor (AhR) ligands. PM2.5 exposure induced higher levels of AhR and CYP1A1 and oxidative stress as evidenced by the higher levels of ROS, MDA, and GSSG in kidneys of mice. PM2.5 exposure led to AhR overexpression and nuclear translocation in proximal renal tubular epithelial cells. Inhibition of AhR reduced CYP1A1 expression and PM2.5-increased levels of ROS, MDA and GSSG. Our study suggested metformin can mitigate PM2.5-induced oxidative stress by inhibiting the AhR/CYP1A1 pathway. These findings illuminated the role of AhR/CYP1A1 pathway in PM2.5-induced kidney injury and the protective effect of metformin on PM2.5-induced cellular damage, offering new insights for air pollution-related renal diseases. [ABSTRACT FROM AUTHOR]