Perilous rock rupture is dominated by damage and fracture of the dominant fissure. Define factor of safety of perilous rock as the ratio of the damage fracture tenacity at the end area of the dominant fissure to the union fracture strength factor; Transfer loads acting on perilous rock to the dominant fissure, and divide them into four components, i.e., water pressure in fissure, average shear stress, moment around the end of the dominant fissure, and average tension stress, further, contribute methods to calculate fracture strength factor every components in view of fracture mechanics; Based on these individual fracture strength factors, establish the method to calculate the union fracture strength factor along fracture orientation near the end area of the dominant fissure. Further, on the basis of damage duration of the dominant fissure, provide the formula to solve the fracture tenacity of rock in damage area near the end of the dominant fissure in detal. Case analyses identify that it is reasonable to consider orientation earthquake force in stability analysis of perilous rock, which promulgates the stability status of perilous rock more effective than that by the limit equilibrium principle.
Unstable rock is the typical geological disaster in areas of highway, city and mine. Energy from rupture of unstable rock passes around by excitation wave, which produces significant excitation effect to adjacent unstable rock, and which is one of important reasons to cause the cascading collapse. By the method of wave mechanics calculation equation of peak velocity from unstable rock caused by rest energy through interface between unstable rocks was deduced and established. Based on the rule of Sweden and Canmet, authors proposed damage criteria of unstable rock under excitation effect. According to damage mechanics, authors set up estimation method of microcrack being likely activated to rest unstable rock under excitation effect. Example analysis shows that problem considering excitation damage is an important way of promoting the scientific and transient security analysis of unstable rock. Research results have a positive significance for science reveals of unstable rock failure mechanism.
Aryl hydrocarbon receptor (AHR) genomic pathway has been well-characterized in a number of respiratory diseases. In addition, the cytoplasmic AHR protein may act as an adaptor of E3 ubiquitin ligase. In this study, the physiological functions of AHR that regulate cell proliferation were explored using the CRISPR/Cas9 system. The doubling-time of the AHR-KO clones of A549 and BEAS-2B was observed to be prolonged. The attenuation of proliferation potential was strongly associated with either the induction of p27Kip1 or the impairment in mitogenic signal transduction driven by the epidermal growth factor (EGF) and EGF receptor (EGFR). We found that the leucine-rich repeats and immunoglobulin-like domains 1 (LRIG1), a repressor of EGFR, was induced in the absence of AHR in vitro and in vivo. The LRIG1 tends to degrade via a proteasome dependent manner by interacting with AHR in wild-type cells. Either LRIG1 or a disintegrin and metalloprotease 17 (ADAM17) were accumulated in AHR-defective cells, consequently accelerating the degradation of EGFR, and attenuating the response to mitogenic stimulation. We also affirmed low AHR but high LRIG1 levels in lung tissues of chronic obstructive pulmonary disease (COPD) patients. This might partially elucidate the sluggish tissue repairment and developing inflammation in COPD patients.
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