York University

Hand grip strength (HGS) is a predictor of cognitive decline in aging. To understand the direct and indirect mechanisms underlying this association, we performed integrative analyses of genetic, cognitive, and autopsy data. A polygenic risk score for HGS (PRSHGS) was calculated in two independent studies of aging (total n = 25,227). Cross-sectional and longitudinal modeling, including mediation with physical activity, assessed the effects of PRSHGS on cognitive performance and postmortem neuropathology. In both cohorts, higher PRSHGS predicted better global cognitive performance (p = 7.77 × 10-4 and p = 0.025) and improved the predictive performance of an Alzheimer's disease PRS (likelihood ratio test p = 2.5 × 10-5 and p = 0.007). PRSHGS was not associated with levels of any postmortem neuropathology. PRSHGS effects on cognition were only partially and inconsistently mediated by physical activity. Genetic predisposition for greater HGS predicts better cognitive performance in late life, independent from Alzheimer's disease-related neuropathology.

Severity of aortic regurgitation correlates with atrial stretch and fibrillation. Uncovering stretch-mediated atrial remodeling prior to ventricular pathology will help define optimal timing of interventions.

Achieving high tensile ductility is crucial in structural materials, as it supports reliable load-bearing performance and good formability. Steels, the most widely used structural metals, show a wide range of elongation to failure, from a few percent to a few tens of percent. Recently, heterostructured materials (HMs) have been reported to exhibit superior tensile properties that surpass those of their homogeneous counterparts. Classical HMs with heterogeneity in the length scale less than a few hundred nanometres attribute their enhanced mechanical performance mainly to the hetero-deformation induced (HDI) hardening. However, the underlying mechanisms for HMs with mesoscale heterogeneities, i.e., in the length scale of a few hundred micrometers, are overlooked. Recent advances in additive manufacturing (AM) have provided opportunities to fabricate HMs over the mesoscale range with structural complexity. In this work, we employ the AM method to fabricate a type of mesoscale HM: bi-metallic heterostructured steels (HSs), consisting of 316L and PH17-4 stainless steels with distinct tensile strength and ductility. By tuning the ratios and fractions of 316L/PH17-4, we achieved 27.3%, 11.5%, and 1.8% improvements in the tensile ductility, ultimate tensile strength, and yield strength over 316L, respectively. Such enhanced tensile properties are mainly attributed to (i) confined-necking co-deformation, where the necking of PH17-4 is confined and delayed by 316L, offering more work hardening to the whole sample, (ii) switching between necking-induced and shear-induced failure modes, and (iii) the HDI hardening effect. This study paves the way for understanding and designing bi-metallic HSs with improved tensile properties using AM methods.

Equivalence testing, also called negligible effect significance testing (NEST), is appropriate when a researcher would like to find evidence of a negligible association. However, since equivalence testing/NEST procedures are newer and considerably less popular than traditional difference-based null hypothesis significance testing, it is useful to give a gentle introduction to these methods. Accordingly, this tutorial article aims to provide an overview of NEST/equivalence testing procedures by describing the nature of the procedures, explaining when they should be used, defining what considerations should go into their application (including selecting a minimally meaningful effect size), and outlining how they may be conducted and interpreted. The tutorial article also includes examples and code in open-source software to illustrate how these procedures may be applied to real data. (PsycInfo Database Record (c) 2026 APA, all rights reserved).

• Deep stratification from magma ocean crystallization is restructured by bottom-heating. • Stratification is restructured by stirring or drainage of fractional melts. • Fractional melt drainage to a growing BMO depletes the deep solid mantle. • An analytical model predicts regime and timescale of stratification restructuring. • Stratification in Earth’s deep mantle should re-differentiate in at most ∼1 Gy. Differentiation of Earth’s magma ocean likely created chemical heterogeneity, leading to a gradually stratified deep mantle overlying a basal magma ocean (BMO). The Earth’s thermochemical evolution hinges on the fate of this early stratification. At this stage, the solid mantle is near-solidus, so deep convective motions are probably strongly influenced by solid-liquid phase change. However, the preservation or modification of stratification is poorly understood in the presence of partial melting. We investigate the evolution of a compositionally stratified deep mantle considering melt-related processes and interaction between the solid mantle and BMO. We determine that bottom-heating of the stratified solid mantle by a radioactively heated BMO or a cooling core powers restructuring of stratification in two regimes: (1) if produced melt can drain effectively, downward percolation of fractional melt removes the enriched, dense, stratifying component to the growing BMO; (2) otherwise, hot or melt-rich plumes stir the initially stratified material, which retains its original composition. We present a numerically-validated analytical model which predicts both the timescale and the different regimes of stratification restructuring. Applying this model to Earth, we determine that gradual stratification in the deep solid mantle would have been restructured by the early Archean by drainage of low-degree partial melts. This process would leave the early Earth with a depleted deep mantle only slightly denser than the shallow mantle, and a voluminous BMO. The deep solid reservoirs may be relatively easily entrained into the convecting shallow mantle, whereas the BMO could act as a more persistent source of heterogeneity.