Detrended fluctuation analysis of intracranial pressure predicts outcome following traumatic brain injury

Detrended fluctuation analysis (DFA) is a recently developed technique suitable for describing scaling behavior of variability in physiological signals. The purpose of this study is to explore applicability of DFA methods to intracranial pressure (ICP) signals recorded in patients with traumatic brain injury (TBI). In addition to establishing the degree of fit of the power-law scaling model of detrended fluctuations of ICP in TBI patients, we also examined the relationship of DFA coefficients (scaling exponent and intercept) to: 1) measures of initial neurological functioning; 2) measures of functional outcome at six month follow-up; and 3) measures of outcome, controlling for patient characteristics, and initial neurological status. In a sample of 147 moderate-to-severely injured TBI patients, we found that a higher DFA scaling exponent is significantly associated with poorer initial neurological functioning, and that lower DFA intercept and higher DFA scaling exponent jointly predict poorer functional outcome at six month follow-up, even after statistical control for covariates reflecting initial neurological condition. DFA describes properties of ICP signal in TBI patients that are associated with both initial neurological condition and outcome at six months postinjury.      

Determining the Surface Tension of Microliter Amounts of Liquid

We describe a method for determining the surface tension of liquids by measuring the pull-off force between curved surfaces with a bridging droplet. The technique is useful for cases when only very small amounts of liquid are available, as in medical and biological applications. Data on the surface tension of saliva samples are in agreement with literature values. Copyright 2000 Academic Press.     

The first three anisotropy constants of nickel

The technique of ferromagnetic resonance at 23 GHz has been used to determine the first three anisotropy constants of pure Ni down to 4.2K. A temperature and orientation dependent linewidth has also been observed.