There is an unmet need of models for early prediction of morbidity and mortality of Coronavirus disease‐19 (COVID‐19). We aimed to a) identify complement‐related genetic variants associated with the clinical outcomes of ICU hospitalization and death, b) develop an artificial neural network (ANN) predicting these outcomes and c) validate whether complement‐related variants are associated with an impaired complement phenotype. We prospectively recruited consecutive adult patients of Caucasian origin, hospitalized due to COVID‐19. Through targeted next‐generation sequencing, we identified variants in complement factor H/CFH, CFB, CFH‐related, CFD, CD55, C3, C5, CFI, CD46, thrombomodulin/THBD, and A Disintegrin and Metalloproteinase with Thrombospondin motifs (ADAMTS13). Among 381 variants in 133 patients, we identified 5 critical variants associated with severe COVID‐19: rs2547438 (C3), rs2250656 (C3), rs1042580 (THBD), rs800292 (CFH) and rs414628 (CFHR1). Using age, gender and presence or absence of each variant, we developed an ANN predicting morbidity and mortality in 89.47% of the examined population. Furthermore, THBD and C3a levels were significantly increased in severe COVID‐19 patients and those harbouring relevant variants. Thus, we reveal for the first time an ANN accurately predicting ICU hospitalization and death in COVID‐19 patients, based on genetic variants in complement genes, age and gender. Importantly, we confirm that genetic dysregulation is associated with impaired complement phenotype.

This paper presents the results of a series of hollow cylinder tests carried out to investigate the role of drainage conditions on the response of railway track foundation materials during cyclic loading. Three sand-clay mixes were tested. It was found that, below a certain cyclic shear stress threshold, and depending on the drainage conditions, changes in principal stress direction should not adversely affect the cyclic stability of a railway foundation. However, significant stiffness degradation and failure may occur if this cyclic shear stress threshold is exceeded. The cyclic shear stress threshold increased with moderate additions of clay per unit volume of sand, and reduced significantly when specimen drainage was prevented. For the materials tested, the cyclic shear stress threshold in free-to-drain conditions was generally similar to the cyclic shear stress in the soil immediately below a 0·3 m deep ballast bed, but comfortably greater than the cyclic stress at a depth of 1 m below the sleeper base. In undrained conditions, the cyclic shear stress threshold was generally similar to the cyclic shear stress at a depth of 1 m below the sleeper base. This has implications for the suitability of such materials for railway track foundations.

This paper presents results of a series of hollow cylinder tests carried out to investigate the undrained behaviour of saturated railway track foundation materials during cyclic loading involving principal stress rotation. Four sand–clay mixes representative of real railway track foundation materials were investigated. It was found that moderate additions of clay (up to ∼14% by weight) increased the cyclic shear stress threshold at which significant excess pore pressures started to accumulate. After the cyclic shear stress threshold had been exceeded, the rate of pore pressure increase with the logarithm of axial strain was greatest for the material having a clay content of 11%. Excess pore pressure generation reduced with increasing intergranular and global void ratio, with the global void ratio being perhaps the more useful indicator because of the reduced amount of scatter and higher correlation of the idealized relationship.

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