Conditions for Bias from Differential Left Truncation

Bias due to left truncation and left censoring in longitudinal studies of developmental and disease processes.

In longitudinal studies of developmental and disease processes, participants are followed prospectively with intermediate milestones identified as they occur. Frequently, studies enroll participants over a range of ages including ages at which some participants' milestones have already passed. Ages at milestones that occur prior to study entry are left censored if individuals are enrolled in th...

Left Truncation Bias as a Potential Explanation for the Protective Effect of Smoking on Preeclampsia

BACKGROUND We carried out a study to examine whether left truncation bias could explain the negative association between smoking and preeclampsia. METHODS Monte Carlo and other simulation models were used to determine the effect of differential rates of early pregnancy loss among smokers on the relation between smoking and preeclampsia at ≥20 weeks' gestation. Assumptions included no associat...

Correcting Publication Bias In Meta-Analysis: A Truncation Approach

A Comparison of the Effectiveness of Cognitive Bias Modification in Real and Placebo Conditions on Attentional Bias and Approach Bias in Opium Abusers

Background & Aim: Inability to control drug use is considered a core aspect of drug dependency. Part of this inability is due to cognitive biases resulting from individuals’ constant usage of drugs. The aim of the present study was to compare the effectiveness of cognitive bias modification in real and placebo conditions on attentional bias and approach bias in opium abusers. Methods: This stud...

Unusual truncation of N-acylated peptoids under acidic conditions.

The terminal amino groups of peptoids have often been protected with acetyl groups to improve cell permeability and therapeutic potential, and to prevent the poisoning of the catalysts in organometallic reactions. Interestingly, the unusual truncation of the terminal peptoid unit has sometimes been encountered when the acetylated linear peptoids were treated with a TFA cleavage cocktail. In thi...