University of Groningen

About: University of Groningen is a education organization based out in Groningen, Groningen, Netherlands. It is known for research contribution in the topics: Population & Context (language use). The organization has 36346 authors who have published 69116 publications receiving 2940370 citations. The organization is also known as: Rijksuniversiteit Groningen & RUG.

A molecular dynamics study of polarizable water

Abstract: We have investigated the effect of adding a point polarizability to a SPC like rigid water model in molecular dynamics simulations A new algorithm for calculating the induced dipole moments based on a predictive, instead of an iterative scheme, is presented The predictive scheme considerably reduces the demand on computer time Both schemes gives identical results for energy, structure and dynamics In the liquid phase simulations of the polarizable water model the total dipole moment is enhanced from its static gas phase value of 1·85 D to 3·2 D The radial distribution functions indicate an increased structure as compared to SPC water Dynamic properties are slower than for the original SPC model Further adjustments of the hard core of the polarizable SPC model to yield a better energy estimate reduces the total dipole moment to 2·9 D This model, the polarizable SPC (PSPC) water, enhances the agreement with the original SPC structure and improves the dynamical properties of the model In order to si

Periventricular cerebral white matter lesions predict rate of cognitive decline

Abstract: The prospect of declining cognitive functions is a major fear for many elderly persons. Cerebral white matter lesions, as commonly found with magnetic resonance imaging, have been associated with cognitive dysfunction in cross-sectional studies. Only a few longitudinal studies using small cohorts confirmed these findings. We examined the relation between severity of white matter lesions and cognitive decline over a nearly 10-year period in 563 elderly subjects sampled from the general nondemented Dutch population. Severity of white matter lesions was scored for periventricular and subcortical regions separately using an extensive semiquantitative scale. Cognitive function was measured by the Mini-Mental State Examination at regular time intervals during 1990 to 2000, and magnetic resonance imaging scans were made in 1995 to 1996. More severe white matter lesions were associated with more rapid cognitive decline over a mean follow-up period of 7.3 years (standard deviation, 1.5). After adjusting for age, gender, educational level, measures of depression, and brain atrophy and infarcts, subjects with severe periventricular white matter lesions experienced cognitive decline nearly three times as fast (0.28 Mini-Mental State Examination points/year [95% confidence interval, 0.20-0.36]) as the average (0.10 points/year [95% confidence interval, 0.09-0.11]). There was no independent relationship between severity of subcortical white matter lesions and rate of cognitive decline.