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A type of artificial boundary layer for the numerical simulation of wave propagation, which is named the gradient viscoelastic (GV) boundary layer, is proposed in this study. The setting of the GV boundary layer was established according to the propagation behavior of the longitudinal wave in the elastic GV rod, the analytical solution of the longitudinal wave propagation in the GV rod was obtained via the Wentzel–Kramers–Brillouin (WKB) method, and the zero-reflection and attenuation condition was determined. The settings of the GV boundary layer in the 1D and 2D time-domain simulations were applied to numerical examples and then compared. Numerical results showed that setting the GV boundary layer in the structure could remarkably reduce the error caused by truncation, and the combined GV boundary and low-reflection (LR) boundary presented the best combination. These results provide a simple method for artificial boundary layer setting to solve numerical wave simulations in the time domain. [ABSTRACT FROM AUTHOR]

To compare the diagnostic performance of contrast enhanced CT (CE-CT), CE-CT combined with non-enhanced MRI (NE-MRI) or contrast enhanced MRI (CE-MRI) for colorectal liver metastasis (CRLM). Sixty-six colorectal cancer patients with 198 focal liver lesions who underwent preoperative abdominal CE-CT and MRI examinations were included respectively. The images were assessed independently by two readers in three protocols (1: CE-CT, 2: CE-CT+NE-MRI, 3: CE-CT+CE-MRI). The diagnostic performance of each protocol was analyzed by receiver operating characteristic (ROC) curve and the areas under ROC (AUCs) were calculated and compared. The detection rates of protocol 2 were 90.9%-92.9% for liver lesions and 86.4%-89.6% for CRLM, and both significantly higher than protocol 1 of 82.8%-85.4% and 76.8%-80.8% (p <0.001-0.001), whereas similar to protocol 3 of 91.9%-94.4% and 87.2%-91.2% (p 0.250-1.000). The AUCs of protocol 2 were greater than protocol 1 for all lesions (0.914-0.934 vs. 0.779-0.799, p <0.001) and lesions < 10mm (0.726-0.776 vs. 0.528-0.561, p <0.001), and were not inferior to that of protocol 3 (0.929-0.949 in all lesions and 0.754-0.821 in lesion < 10mm, p 0.053-0.162). CE-CT combined with NE-MRI offered superior diagnostic performance for CRLM compared to CE-CT alone and showed comparable performance to CE-CT combined with CE-MRI. [ABSTRACT FROM AUTHOR]

The global space sector has to increasingly consider sustainability concerns in the orbit, given the rising challenge of space debris. In which direction the management of space debris will develop in terms of technological solutions, policies, and actor strategies remains still unclear. This paper applies the concept of 'global socio-technical regimes' to better understand how actors in the global space sector frame, conceive, and legitimize the space debris problem. More specifically, we apply a discourse network analysis method – sociotechnical configuration analysis – to identify and map different value orientations by core actors over the last fifteen years. This analysis reveals three development stages in the discourse: a problem identification period (2007–2011), followed by the rise of national interests amidst increasing promises of space-based infrastructures (2012–2015), and finally, the emergence of a global socio-technical regime that increasingly connects space sustainability with Earth-bound sustainability (2016–2019). Based on our analysis, we expect that ensuring future earth-space sustainability will include a broader mix of challenges. Future approaches to space debris management will have to consider a broader and clearer problem framing to help inform effective policy making. • We mapped the institutional structures that shape global space debris management. • We analyzed value considerations of actors by means of socio-technical configuration analysis. • We observed a broader sustainability framing concerning space over time. • There is a growing consensus on Earth-bound and space-based interdependencies. • Future policies to address space debris require an integrative approach. [ABSTRACT FROM AUTHOR]

In observational studies, statins have been suggested to have protective effects on venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE). To this aim, we performed a two-sample mendelian randomization (MR) analysis to determine whether these associations were causal. Data on the single nucleotide polymorphisms (SNPs) related to statin medication were obtained from the FinnGen study, and data for VTE, PE and DVT of lower extremities (LEDVT) were from the UK Biobank study, respectively. Inverse variance weighted (IVW) method was used as the principal analysis of MR, and sensitivity analysis was performed to detect horizontal pleiotropy and heterogeneity. MR estimates showed an inverse causal association between statin medication and the risk of VTE (odds ratio [OR]: 0.999, 95% CI: 0.998–1.000, P = 0.004), PE (OR: 0.999, 95% CI: 0.999–1.000, P = 0.011) and LEDVT (OR: 0.999, 95% CI: 0.999–1.000, P = 0.008). Our findings provide direct evidence that statins might decrease the risk of VTE, PE and LEDVT in agreement with observational studies. The specific mechanism of statin therapy for venous thromboembolism needs to be further studied. • Available evidence suggests that the effect of statins on venous thromboembolism outcomes remains inconclusive. • The Mendelian Randomization results showed that statin might decrease the risk of venous thromboembolism diseases. • This study provides evidence that statins have a protective effect on venous thromboembolism. [ABSTRACT FROM AUTHOR]