RESUMO
Areal optical surface topography measurement is an emerging technology for industrial quality control. However, neither calibration procedures nor the utilization of material measures are standardized. State of the art is the calibration of a set of metrological characteristics with multiple calibration samples (material measures). Here, we propose a new calibration sample (artefact) capable of providing the entire set of relevant metrological characteristics within only one single sample. Our calibration artefact features multiple material measures and is manufactured with two-photon laser lithography (direct laser writing, DLW). This enables a holistic calibration of areal topography measuring instruments with only one series of measurements and without changing the sample.
RESUMO
The measurement of force-distance curves on a single bacterium provides a unique opportunity to detect properties such as the turgor pressure under various environmental conditions. Marine bacteria are very interesting candidates for the production of pharmaceuticals, but are only little studied so far. Therefore, the elastic behavior of Paracoccus seriniphilus, an enzyme producing marine organism, is presented in this study. After a careful evaluation of the optimal measurement conditions, the spring constant and the turgor pressure are determined as a function of ionic strength and pH. Whereas the ionic strength changes the turgor pressure passively, the results give a hint that the change to acidic pH increases the turgor pressure by an active mechanism. Furthermore, it could be shown, that P. seriniphilus has adhesive protrusions outside its cell wall.
