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Normative models are increasingly used to characterize individual-level brain deviations in neuroimaging studies, but their performance depends heavily on the reference sample used for training or adaptation. In this study, we systematically investigated how sample size and covariate composition of the reference cohort influence model fit, deviation estimates, and clinical readouts in Alzheimer's disease (AD). Using a discovery dataset (OASIS-3, n = 1032), we trained models on healthy control...

Normative models are increasingly used to characterize individual-level brain deviations in neuroimaging studies, but their performance depends heavily on the reference sample used for training or adaptation. In this study, we systematically investigated how sample size and covariate composition of the reference cohort influence model fit, deviation estimates, and clinical readouts in Alzheimer's disease (AD). Using a discovery dataset (OASIS-3, n = 1032), we trained models on healthy control...

Women and children were executed in an elaborate prehistoric ritual

New anatomical research reveals the one trick all ponies know

RNA polymerase I (Pol I) is a specialized eukaryotic enzyme responsible for transcribing ribosomal DNA into precursor rRNA, a process that initiates ribosome biogenesis and supports cellular growth, metabolism, and proliferation. Recent structural and mechanistic studies have revealed unique features of Pol I architecture that enable high transcriptional output and tight regulatory control. Pol I activity is dynamically regulated by signaling pathways, epigenetic mechanisms, and chromatin...

Falls in older adults result from declines in muscle quality. This study aimed to examine differences in load-velocity profile (LVP) metrics, muscle ultrasound measures, strength, functional tests, and lifestyle between older adults with and without falls, and to analyze their association with sit-to-stand power. Sixty-two older adults (41 non-fallers, 21 fallers; mean age 68.32 ± 5.07 years) underwent three lab sessions. LVP was determined via functional electromechanical dynamometry during a...

Sleep disturbances and Alzheimer's disease (AD) are interconnected public health challenges. However, the underlying mechanisms of their complex relationships remain elusive. Here, we propose a hypothetical integrative, stream-like model outlining how external and internal exposome factors accelerate brain aging, thereby exacerbating circadian dysregulation, orexin-mediated hyperexcitability, metabolic imbalance, and inflammaging. These changes can lead to increased sleep fragmentation and...

Sjögren's disease, an autoimmune disorder characterized by the presence of circulating autoantibodies and lymphocytic infiltrates in salivary glands, predominantly affects women later in life. By leveraging genetically heterogeneous UM-HET3 mice, this study tested the hypothesis that female sex and aging interact to shape susceptibility to autoimmunity and salivary gland inflammation. Female and male UM-HET3 mice were evaluated across the adult lifespan for the development of glandular...