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In order to study the characteristics of porosity, permeability and stress sensitivity of middle rank coal reservoir in Tucheng syncline and their influence on coalbed methane exploitation, coal core samples of coal seams 1#, 3#, 5#, 15#, 17#, 291# and 292# in Tucheng syncline were collected. Based on the overburden porosity and permeability test, the variation law of porosity and permeability with effective stress of each coal reservoir is compared, and the sensitivity of effective stress of each coal reservoir is analyzed by using the parameters of porosity stress damage rate, permeability stress damage rate and permeability curvature. The results show that: with the increase of effective stress, the coal reservoir porosity and gas permeability were negative exponent; the stress sensitivity coefficient of test coal reservoir is 0.035-0.073 MPa-1, and the stress sensitivity regression coefficient of 3# coal sample is the largest; the stress damage rate of porosity increases with the increase of effective stress, and the stress damage rate of 3# coal sample with shallow burial depth is relatively large. The permeability stress damage rate increases exponentially with the increase of effective stress, and the permeability damage rate of 3# coal sample is obviously larger than that of other coal samples. The permeability curvature of coal reservoir decreases exponentially with the increase of effective stress.Under the same effective stress, the stress sensitivity of 3# coal seam is greater than that of 5#, 15# and 29# coal seam, and the stress sensitivity of 1# and 17# coal seam is the weakest.

Background: Liver metastasis (LIM) is the most common distant site of metastasis in small intestinal stromal tumors (SISTs). The aim of this study was to determine the risk and prognostic factors associated with LIM in patients with SISTs. Methods: Patients diagnosed with gastrointestinal stromal tumors between 2010 and 2019 were selected from the Surveillance, Epidemiology, and End Results (SEER) database. Univariate and multivariate logistic regression models, as well as a Cox regression model were used to explore the risk factors associated with the development and prognosis of LIM. Additionally, the overall survival (OS) of patients with LIM was analyzed using the Kaplan‐Meier method. Furthermore, a predictive nomogram was constructed, and the model's performance was evaluated using receiver operating characteristic (ROC) curve, calibration curve, and decision curve analysis (DCA). Results: A total of 1582 eligible patients with SISTs were included, among whom 146 (9.2%) were diagnosed with LIM. Poor tumor grade, absence of surgery, later T‐stage, and no chemotherapy were associated with an increased risk of developing LIM. The nomogram prediction model achieved an AUC of 0.810, 95% Confidence Interval (CI) 0.773–0.846, indicating good performance, and the calibration curve showed excellent accuracy in predicting LIM. The OS rate of patients with LIM was significantly lower than that of patients without LIM (p < 0.001). Conclusions: Patients with SISTs who are at high risk of developing LIM deserve more attention during follow‐up, as LIM can significantly affect patient prognosis. The nomogram demonstrated good calibration and discrimination for predicting LIM. [ABSTRACT FROM AUTHOR]