Objective To investigate the levels and variations of radon concentration in Wuhan subway and to provide data support for ensuring public radiation safety. Methods The typical sampling method was used to select 18 stations from Wuhan Metro Line 2, Line 3, and Line 7 for the measurement and evaluation of radon in the air. Using RAD7 electronic radon detector and continuous radon measurement method, radon concentrations in station platforms and station halls were investigated. Analysis of variance and t test were used for statistical analysis. Results The concentration of radon in Wuhan subway ranged from 8.8 to 16.2 Bq/m³, with an average of 11.5 Bq/m³, which is far lower than the limit set by Requirements for Radiological Protection for Radon in Public Underground Structure and Using Geothermal Water (WS/T 668-2019). There was no significant difference in radon concentration between station platform and station hall (t = −0.081, P > 0.05). There was no significant difference in radon concentration between different lines (F = 0.338, P > 0.05). On the whole, the radon concentration in summer was lower than that in winter, and there was no significant difference between months (F = 1.280, P > 0.05). Conclusion The radon concentrations in Wuhan subway result in low-dose radiation, and there is no significant health risk of radon exposure.

Objective To investigate the levels and variations of radon concentration in Wuhan subway and to provide data support for ensuring public radiation safety. Methods The typical sampling method was used to select 18 stations from Wuhan Metro Line 2, Line 3, and Line 7 for the measurement and evaluation of radon in the air. Using RAD7 electronic radon detector and continuous radon measurement method, radon concentrations in station platforms and station halls were investigated. Analysis of variance and t test were used for statistical analysis. Results The concentration of radon in Wuhan subway ranged from 8.8 to 16.2 Bq/m³, with an average of 11.5 Bq/m³, which is far lower than the limit set by Requirements for Radiological Protection for Radon in Public Underground Structure and Using Geothermal Water (WS/T 668-2019). There was no significant difference in radon concentration between station platform and station hall (t = −0.081, P > 0.05). There was no significant difference in radon concentration between different lines (F = 0.338, P > 0.05). On the whole, the radon concentration in summer was lower than that in winter, and there was no significant difference between months (F = 1.280, P > 0.05). Conclusion The radon concentrations in Wuhan subway result in low-dose radiation, and there is no significant health risk of radon exposure.

ObjectiveTo investigate the association between estimated glucose disposal rate （eGDR） and the severity of coronary heart disease. MethodsWe conducted a hospital-based cross-sectional study that included 1258 patients （mean age： 62（53-68） years） who underwent coronary angiography for suspected coronary artery disease （53.9% were male）. Insulin resistance level （IR） was calculated according to eGDR formula： eGDR = 21.158 - （0.09 × WC） - （3.407 × hypertension） - （0.551 × HbA1c） ［hypertension （yes = 1 / no = 0）， HbA1c = HbA1c （%）］. Subjects were grouped according to the eGDR quantile. CAD severity was determined by the number of narrowed vessels： no-obstructive CAD group （all coronary stenosis were<50%， n=704）， Single-vessel CAD group （only one involved major coronary artery stenosis≥50%， n=205）， Multi-vessel CAD group （two or more involved major coronary arteries stenosis≥50%， n=349）； Multivariate logistic regression model was used to analyze the association between eGDR and CAD severity. The linear relationship between eGDR and CAD in the whole range of eGDR was analyzed using restricted cubic spline. Subgroup analyses were used to assess the association between eGDR and CAD severity in different diabetic states. Receiver operating characteristic （ROC） curve analysis were used to evaluate the value of eGDR in improving CAD recognition. ResultsA decrease in the eGDR index was significantly associated with an increased risk of CAD severity （OR： 2.79； 95%CI： 1.72~4.55； P<0.001）. In multivariate logistic regression models， individuals with the lowest quantile of eGDR （T1） were 2.79 times more likely to develop multi-vessel CAD than those with the highest quantile of eGDR （T3） （OR： 2.79； 95%CI： 1.72~4.55； P<0.001）. Multivariate restricted cubic spline analysis showed that eGDR was negatively associated with CAD and multi-vessel CAD （P-nonlinear>0.05）. In non-diabetic patients， compared with the reference group （T3）， the T1 group had a significantly increased risk of CAD （OR： 1.42； 95% CI： 1.00~2.01； P<0.05） and multi-vessel CAD （OR： 1.86； 95%CI： 1.21~2.86； P<0.05）. No statistical association was found between eGDR and CAD in diabetic patients. In ROC curve analysis， when eGDR was added to traditional model for CAD， significant improvements were observed in the model's recognition of CAD and multi-vessel CAD. ConclusionOur study shows eGDR levels are inversely associated with CAD and CAD severity. eGDR， as a non-insulin measure to assess IR， could be a valuable indicator of CAD severity for population.