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COVID-19 can induce neurological sequelae, negatively affecting the quality of life. Unravelling this illness's impact on structural brain connectivity, white-matter microstructure (WMM), and cognitive performance may help elucidate its implications. This cross-sectional study aimed to investigate differences in these factors between former hospitalised COVID-19 patients (COV) and healthy controls. Group differences in structural brain connectivity were explored using Welch-two sample t-tests and two-sample Mann–Whitney U tests. Multivariate linear models were constructed (one per region) to examine fixel-based group differences. Differences in cognitive performance between groups were investigated using Wilcoxon Rank Sum tests. Possible effects of bundle-specific FD measures on cognitive performance were explored using a two-group path model. No differences in whole-brain structural organisation were found. Bundle-specific metrics showed reduced fiber density (p = 0.012, Hedges' g = 0.884) and fiber density cross-section (p = 0.007, Hedges' g = 0.945) in the motor segment of the corpus callosum in COV compared to healthy controls. Cognitive performance on the motor praxis and digit symbol substitution tests was worse in COV than healthy controls (p < 0.001, r = 0.688; p = 0.013, r = 422, respectively). Associations between the cognitive performance and bundle-specific FD measures differed significantly between groups. WMM and cognitive performance differences were observed between COV and healthy controls. [ABSTRACT FROM AUTHOR]

This work demonstrates a successful in situ method capable of producing an ultra-strong novel Ti composite without aluminium and vanadium. In this method, selective laser melting is used to conduct in situ alloying and reinforcing of a Ti/10.5 wt% Mo 2 C powder mixture. It is shown that this leads to a metastable β-Ti matrix homogeneously reinforced by high aspect ratio, 50-200 nm wide and up to several micrometre long TiC whiskers. The transformations of the phases are controlled by decomposition, dissolution, diffusion, and reformation of constituents. The whisker morphology of in situ formed TiC particles is associated with directional crystal growth along the TiC <110> direction. The developed TiC reinforced β-Ti alloy combines a hardness over 500 HV, a Young's modulus of 126 GPa, and an ultimate compressive strength of 1642 MPa. Improving the ductility of this composite is the subject of another work.