ABSTRACT
SUMMARY: The Helmholtz Network for Bioinformatics (HNB) is a joint venture of eleven German bioinformatics research groups that offers convenient access to numerous bioinformatics resources through a single web portal. The 'Guided Solution Finder' which is available through the HNB portal helps users to locate the appropriate resources to answer their queries by employing a detailed, tree-like questionnaire. Furthermore, automated complex tool cascades ('tasks'), involving resources located on different servers, have been implemented, allowing users to perform comprehensive data analyses without the requirement of further manual intervention for data transfer and re-formatting. Currently, automated cascades for the analysis of regulatory DNA segments as well as for the prediction of protein functional properties are provided. AVAILABILITY: The HNB portal is available at http://www.hnbioinfo.de
Subject(s)
Algorithms , Computational Biology/methods , Database Management Systems , Information Storage and Retrieval/methods , Internet , Sequence Analysis, DNA/methods , Sequence Analysis, Protein/methods , User-Computer Interface , Computational Biology/organization & administration , Germany , Interinstitutional Relations , SoftwareABSTRACT
Velocity profiles of human blood flowing through vertical and horizontal glass tubes (25-100 microns ID) were measured as a function of time following a sudden reduction of wall shear stress (tau w) from a high value to values ranging from 2 to 100 mPa. Cell velocities at various radial positions were determined off-line from video recordings by digital image analysis. In vertical tubes, symmetric velocity profiles were obtained that developed increasing bluntness with time, particularly at lower tau w and in smaller tubes. In horizontal tubes, velocity profiles developed strong asymmetry as a function of time. Red blood cell (RBC) sedimentation was associated with uniform low flow velocities in the concentrating cell sediment, whereas faster flow and almost parabolic profiles were observed in the supernatant plasma region. Calculations of effective blood viscosity showed a decrease with time at low tau w in vertical tubes but an increase in horizontal tubes. The differences between profile shape and effective viscosity in vertical and horizontal tubes disappeared at tau w > 50 mPa. These findings are related to the cross-sectional distribution of RBC, which depends on RBC aggregation and sedimentation.
