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    A modular in vitro flow model to analyse blood-surface interactions under physiological conditions
    (Berlin : De Gruyter, 2021) Valtin, Juliane; Behrens, Stephan; Maitz, Manfred F.; Schmieder, Florian; Sonntag, Frank; Werner, Carsten
    Newly developed materials for blood-contacting devices need to undergo hemocompatibility testing to prove compliance with clinical requirements. However, many current in vitro models disregard the influence of flow conditions and blood exchange as it occurs in vivo. Here, we present a flow model which allows testing of blood-surface interactions under more physiological conditions. This modular platform consists of a triple-pump-chip and a microchannel-chip with a customizable surface. Flow conditions can be adjusted individually within the physiological range. A performance test with whole blood confirmed the hemocompatibility of our modular platform. Hemolysis was negligible, inflammation and hemostasis parameters were comparable to those detected in a previously established quasi-static whole blood screening chamber. The steady supply of fresh blood avoids secondary effects by nonphysiological accumulation of activation products. Experiments with three subsequently tested biomaterials showed results similar to literature and our own experience. The reported results suggest that our developed flow model allows the evaluation of blood-contacting materials under physiological flow conditions. By adjusting the occurring wall shear stress, the model can be adapted for selected test conditions.
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    Messanlage zur Untersuchung des Seebeck-Effektes in Polymermaterialien
    (Berlin : De Gruyter, 2020) Jenschke, Wolfgang; Ullrich, Mathias; Krause, Beate; Pötschke, Petra
    The thermoelectric effect named after the physicist Thomas Johann Seebeck has been investigated sufficiently well for all technically relevant metals and has been used for a long time, among other things, for temperature measurement by means of thermocouples. Less well known and researched is the Seebeck effect in polymer materials, which are gaining increasing influence in the sensor industry today. This article describes a measuring system designed specifically to study the Seebeck effect in polymeric samples with the aim of developing tailored polymers for sensory engineering applications using the Seebeck effect. The special requirement of the measuring system is the realization of constant accurate temperature sources.