Measurement Error and Methodologic Issues in Analyses of the Proportion of Variance Explained in Cognition.

Existing studies examining the predictive ability of biomarkers for cognitive outcomes do not account for variance due to measurement error, which could lead to under-estimates of the proportion of variance explained. We used data from the Alzheimer's Disease Neuroimaging Initiative (ADNI) (N = 1084) to estimate the proportion of variance explained by Alzheimer's disease (AD) imaging biomarkers in four cognitive outcomes: memory, executive functioning, language, and visuospatial functioning. We compared estimates from standard models that do not account for measurement error, and multilevel models that do account for measurement error.

Bayesian Response Adaptive Randomization for Randomized Clinical Trials With Continuous Outcomes: The Role of Covariate Adjustment.

Study designs incorporate interim analyses to allow for modifications to the trial design. These analyses may aid decisions regarding sample size, futility, and safety. Furthermore, they may provide evidence about potential differences between treatment arms.

Light green leaf sectors of variegated Dracaena fragrans plants show similar rates of oxygenic photosynthesis tо that of normal, dark green leaf sectors.

Adaptation and functional significance of chlorophyll deficit in the light green leaf sectors of variegated plants are little known. Efficiency of photosystem II for dark and light adapted states (F/F and ΔF/F') and fluorescence decrease rates (R) of light green leaf sectors of Dracaena fragrans L. were studied by methods of PAM-fluorometry and video registration.

A multicenter, randomized, double-blind, placebo-controlled ascending dose study to evaluate the safety, tolerability, pharmacokinetics (PK) and pharmacodynamic (PD) effects of Posiphen in subjects with early Alzheimer's Disease.

Background: Amyloid beta protein (Aβ) is a treatment target in Alzheimer's Disease (AD). Lowering production of its parent protein, APP, has benefits in preclinical models. Posiphen, an orally administered small molecule, binds to an iron-responsive element in APP mRNA and decreases translation of APP and Aβ.