Clinical outcomes and plasma clot permeability and lysability in patients with venous thromboembolism on rivaroxaban : a cohort study

Denser fibrin structure and impaired fibrinolysis reported in patients following venous thromboembolism (VTE) can predict recurrent VTE after cessation of anticoagulation. The aim of the study was to investigate whether the properties of fibrin clot may be useful in predicting adverse events in patients with VTE receiving rivaroxaban. In 132 patients with VTE treated with rivaroxaban for 8 weeks or longer, we determined plasma clot permeability ($K_{s}$) and clot lysis time (CLT) in blood samples collected 2 to 28 hours after rivaroxaban intake (20 mg/d). The primary endpoint was a composite of major and clinically relevant nonmajor bleeding, while the secondary endpoint was recurrent symptomatic VTE. During a median follow‑up of 32 months, the annual rates of primary and secondary endpoints were 3.6% and 2.7%, respectively. There were no differences in $K_{s}$ and CLT between individuals who experienced the primary endpoint and the remainder. Patients with recurrent VTE had lower baseline $K_{s}$ (-26.7%) and prolonged CLT (+20.8%) on rivaroxaban, without differences in rivaroxaban concentrations at the time of blood collection. After adjustment for confounding factors, $K_{s}$ was the only predictor of VTE recurrence on rivaroxaban (odds ratio, 0.23; 95% CI, 0.06-0.94). Our study suggests that $K_{s}$ assessed on rivaroxaban may provide prognostic information about the risk of recurrent VTE in anticoagulated patients

Influence of Rainfall Events and Surface Inclination on Overland and Subsurface Runoff Formation on Low-Permeable Soil

This paper presents the results of laboratory tests that allowed us to determine the effect of the soil surface inclination and its initial moisture content on the formation of overland and subsurface runoff. The experiments were carried out for the soil that is commonly present in the southern part of Poland, including the Outer Carpathians. The results of these measurements served as a reference for overland runoff calculations using the Richards model, simplified Green–Ampt model, and the empirical model (MSME). The results of the measurements showed that, for low-permeable soil, overland runoff is the dominant form. It was shown that a slope in the range of 2.5–5.0% does not have a significant effect on the amount of overland runoff, but affects its dynamics. The measurements also showed that the starting time and amount of overland runoff are strictly associated with the initial soil moisture content. High soil moisture content in the period preceding the onset of rainfall causes faster generation and an increase in overland runoff, which is caused by the saturation of the surface layer of the soil. This mechanism was confirmed by the results of calculations using the Richards model and measurements of the electrical resistance of the soil. Theoretical calculations showed that the results of the runoff calculations using the Richards and Green–Ampt models are strongly dependent on the hydraulic properties of the soil adopted for the analysis. It was also demonstrated that the modified MSME model satisfactorily estimates the amount of overland and subsurface runoff, but requires parameter calibration based on existing hydrological data

The Setting of Strength Parameters in Stability Analysis of Open-Pit Slope Using the Random Set Method in the Bełchatów Lignite Mine, Central Poland

The slopes of open-pit mines are often at risk of failure. To identify this hazard, stability analyses are performed. An important element of these stability analyses is the reliable selection of input parameter values for the calculations. This selection is difficult because the slopes of the open pit are disturbed by mining activities. In such conditions, rheological processes, intensified by weathering, develop in open-pit slopes. This study is aimed at setting the strength parameters for the stability analysis of open-pit slopes with a developed slide process, using the random set method. The study was performed on the example of the open pit of the Bełchatów lignite mine, central Poland. A four-stage methodology, according to the random set method, was proposed. The methodology covered the following: site investigation, sensitivity analyses, shear strength reduction (SSR) analyses using numerical calculations, and probability analyses of the factor of safety (FoS) calculation results. The setting of the input parameters took into account the peak and residual strength parameters for each lithological unit in the physical model of the open-pit slope. Samples for laboratory tests were taken from the cores of nine test boreholes. The sensitivity analysis included all peak and residual strength parameters for each lithological unit in the body. As a result of the sensitivity analysis, specific strength parameters were adopted that would have a great impact upon the results of the calculations. Selected sets of parameter values were then used for the FoS calculations. The resultant FoS values revealed the probable slide planes. The positions of the slide planes were consistent with the interpreted slide surfaces based on the control boreholes and terrain observations. Knowledge of the slide planes positions and the values of the strength parameters enabled the designing of a securing approach for this landslide, and the taking of preventive measures to reduce this risk