Towards better integrators for dissipative particle dynamics simulations

Coarse-grained models that preserve hydrodynamics provide a natural approach to study collective properties of soft-matter systems. Here, we demonstrate that commonly used integration schemes in dissipative particle dynamics give rise to pronounced artifacts in physical quantities such as the compressibility and the diffusion coefficient. We assess the quality of these integration schemes, including variants based on a recently suggested self-consistent approach, and examine their relative performance. Implications of integrator-induced effects are discussed.

[The psychosocial aspects in orthodontically treated and untreated adults with similar, clearly visible tooth malalignments]. / Psychosoziale Aspekte bei kieferorthopädisch behandelten und unbehandelten Erwachsenen mit ähnlichen, gut sichtbaren Zahnstellungsfehlern.

A study was undertaken to compare the psychosocial aspects of orthodontic treatment or non-treatment of female adults, 25 of whom underwent treatment and 25 of whom did not, with similar, visible malocclusion. Interviews, for which 52 standardized questions were prepared in collaboration with a graduate psychologist, served as the methodological basis of the study. The results of the study indicate that in relation to the aesthetic aspects of orthodontic treatment, the treated group showed a high degree of sensitivity and self perception. Following orthodontic treatment members of this group exhibited a highly significant improvement in their subjective perception of the aesthetic aspects of their dental and facial appearance. In spite of the differences observed in the 2 groups, it nevertheless remains difficult to draw general conclusions or to recommend guidelines which would cover all cases. When the question is to orthodontically treat or not treat female adults, the answer rests with the individual patient.