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Rock mass consists of many discontinuities, such as faults, joints, etc., and layered joints are a common kind of rock mass structure. The joints affect the stress wave propagation, and blasting is an economical and efficient rock fragmentation method for rock mass engineering. So, the rock mass fragmentation effect and construction progress are affected by these layered joints. Numerical studies were carried out to analyze the damage evolution process of intact rock and rock mass with layered joints subjected to blasting loads based on the Riedel–Hiermaier–Thoma (RHT) model in LS-DYNA software (smp s R11.0.), and the effects of the location of initiation points and the fracture distribution on dynamic damage evolution of the rock mass were discussed. Bottom initiation tends to direct the blasting energy toward the blasthole mouth, resulting in effective rock fragmentation and ejection. Gradually adjusting the initiation point upward can improve the stress and damage distribution, allowing some of the blasting stress waves to propagate toward the bottom and enhance the fragmentation of the rock at the bottom. The distribution of layered joints exacerbates the damage to the rock mass on the upstream surface, but also acts as a certain shield to the propagation of stress waves, increasing the asymmetry of the damage distribution. It is useful to know the damage mechanism of the rock mass with layered joints to improve the effect of rock mass fragmentation by blasting. These results have very important theoretical significance and application value for the optimization of blasting construction technology. [ABSTRACT FROM AUTHOR]

In 2009, a novel H1N1 influenza virus caused the first influenza pandemic of the 21st century. Studies have shown that the influenza M gene played important roles in the pathogenicity and transmissibility of the 2009 H1N1 pandemic ((H1N1)pdm09), whilst the underlying mechanism remains unclear. The influenza M gene encodes two proteins, matrix protein 1 and matrix protein 2, which play important roles in viral replication and assembly. In this study, it is found that the M2 protein of the (H1N1)pdm09 virus showed a lower mobility rate than the North America triple-reassortant influenza M2 protein in Polyacrylamide Gel Electrophoresis (PAGE). The site-directed mutations of the amino acids of (H1N1)pdm09 M2 revealed that E79 is responsible for the mobility rate change. Further animal studies showed that the (H1N1)pdm09 containing a single M2-E79K was significantly attenuated compared with the wild-type virus in mice and induced lower proinflammatory cytokines and IFNs in mouse lungs. Further in vitro studies indicated that this mutation also affected NLRP3 inflammasome activation. To reveal the reason why they have different mobility rates, a circular dichroism spectra assay was employed and showed that the two M2 proteins displayed different secondary structures. Overall, our findings suggest that M2 E79 is important for the virus replication and pathogenicity of (H1N1)pdm09 through NLRP3 inflammasome and proinflammatory response. [ABSTRACT FROM AUTHOR]

Background: Radiofrequency catheter ablation (RFCA) represents an important treatment option for atrial fibrillation (AF); however, the recurrence rate following surgery is relatively high. This study aimed to predict the recurrence of AF after RFCA using interpretable machine learning models that combined the triglyceride-glucose (TyG) index and the quantification of left atrial epicardial and pericoronary adipose tissue., Methods: This retrospective study included 325 patients with AF who underwent their first successful RFCA, among whom 79 had confirmed recurrence. The preoperative clinical data of patients were collected, the TyG index was calculated, and computed tomography (CT) image features were quantitatively measured. Multivariate Cox regression analysis was used to identify the independent risk factors for RFCA recurrence, and adjustments being made for various confounding factors. Post-hoc subgroup analysis was conducted to evaluate the predictive value of the TyG index for recurrence in different patient subgroups. Prediction models based on six machine learning algorithms were constructed. The optimal model's features were evaluated using Shapley additive explanations (SHAP)., Results: After adjustment were made for various confounding factors such as comorbidities of AF, Cox regression showed that the volume of left atrial epicardial adipose tissue (LA-EAT), LA-EAT attenuation, left circumflex coronary artery fat attenuation index (LCX-FAI), and the TyG index were independent risk factors for recurrence after RFCA (P<0.001). The support vector machine (SVM) model based on these combined indicators had the best predictive performance, with an area under the curve of 0.793 [95% confidence interval (CI): 0.782-0.805] in the validation set, while its accuracy and positive predictive value were 0.804 and 0.710, respectively. The predictive efficiency of the TyG index appeared to be independent of type 2 diabetes mellitus (T2DM) status (P interaction =0.660)., Conclusions: The SVM model that integrated the TyG index and quantitative CT imaging variables demonstrated good predictive ability for post-RFCA recurrence in patients with AF. Furthermore, the TyG index appeared capable of predicting recurrence independently of T2DM status., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://qims.amegroups.com/article/view/10.21037/qims-24-1393/coif). A.S. is an employee of GE HealthCare China. The other authors have no conflicts of interest to declare., (2024 AME Publishing Company. All rights reserved.)

Objective: To evaluate image quality of low-voltage coronary artery computed tomographic (CT) angiography with low contrast agent in comparison with image quality., Methods: Forty-five patients underwent coronary artery computed tomographic (CT) angiography. They were randomly assigned to 3 groups, group A (n = 15) were scanned in 120 kVp with 350 mgI/ml iodinated contrast agent mode, group B (n = 15) were scanned in 100 kVp with 350 mgI/ml iodinated contrast agent mode, group C (n = 15) were scanned in 100 kVp with 270 mgI/ml iodinated contrast agent mode. Then measured CT attenuation value of three main branches (RCA, LAD and CX) of coronary artery, And compare the SNR, CNR, the effective radiation dose(ED) and iodine intake. The Kappa test were used to quantify inter- and intra-reader agreement in detecting quality of the images under different scanning solutions., Results: Three groups of coronary artery CT image quality was no statistically significant differences (all P values >0.05), Good inter- and intra-reader agreement ( k = 0.754, P < 0.05) for the detection of noise in all the patients. There was significant difference in the CT attenuation of RCA, LAD and CX among the 3 groups (P < 0.05), the CT attenuation was the highest in group B, the CT value of RCA, LAD and CX were 537 ± 90, 505 ± 90, 484 ± 75 HU, respectively.the CT attenuation was the lowest in group C, the CT value of RCA, LAD and CX were 357 ± 126, 360 ± 95, 378 ± 121 HU, respectively. There was no significant difference in the SNR and CNR among the 3 groups (P > 0.05). There was significant difference in the ED among the 3 groups (P < 0.05). The ED value of the group A was bigger than the value of the group B and C. There was no significant difference between the group B and C. Compared the group A and B, the iodine intake of the group C had fallen by 23%., Conclusions: The coronary artery CT angiography using 100 kVp with 270 mgI/ml iodinated contrast agent provide similar objective or subjective image quality compared with the (350 mgI/ml) and the 100 kVp (350 mgI/ml), thus enabling effective dose and iodine intake reduction without loss of diagnostic information.