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Mit Ausgabedatum Juli 2018 wurde die Norm DIN ISO 18457 "Bionik - Bionische Werkstoffe, Strukturen und Bestandteile (ISO 18457:2016) veröffentlicht. Aus diesem Anlass blicken wir auf die bisherigen Aktivitäten zurück, die zur Veröffentlichung von insgesamt drei grundlegenden Normen im Bereich der Bionik geführt haben.
BACKGROUND: In cartilage repair, scaffold-assisted single-step techniques are used to improve the cartilage regeneration. Nevertheless, the fixation of cartilage implants represents a challenge in orthopaedics, particularly in the moist conditions that pertain during arthroscopic surgery. Within the animal kingdom a broad range of species has developed working solutions to intermittent adhesion under challenging conditions. Using a top-down approach we identified promising mechanisms for biomimetic transfer OBJECTIVE: The tree-frog adhesive system served as a test case to analyze the adhesion capacity of a polyglycolic acid (PGA) scaffold with and without a structural modification in a bovine articular cartilage defect model. METHODS: To this end, PGA implants were modified with a simplified foot-pad structure and evaluated on femoral articular bovine cartilage lesions. Non-structured PGA scaffolds were used as control. Both implants were pressed on 20 mm × 20 mm full-thickness femoral cartilage defects using a dynamometer. RESULTS: The structured scaffolds showed a higher adhesion capacity on the cartilage defect than the non-structured original scaffolds. CONCLUSIONS: The results suggest that the adhesion ability can be increased by means of biomimetic structured surfaces without the need of additional chemical treatment and thus significantly facilitate primary fixation procedures.
Earwig wings are highly foldable structures that lack internal muscles. The behaviour and shape changes of the wings during flight are yet unknown. We assume that they meet a great structural challenge to control the occurring deformations and prevent the wing from collapsing. At the folding structures especially, the wing could easily yield to the pressure. Detailed microscopy studies reveal adaptions in the structure and material which are not relevant for folding purposes. The wing is parted into two structurally different areas with, for example, a different trend or stiffness of the wing veins. The storage of stiff or more flexible material shows critical areas which undergo great changes or stress during flight. We verified this with high-speed video recordings. These reveal the extent of the occurring deformations and their locations, and support our assumptions. The video recordings reveal a dynamical change of a concave flexion line. In the static unfolded state, this flexion line blocks a folding line, so that the wing stays unfolded. However, during flight it extends and blocks a second critical folding line and prevents the wing from collapsing. With these results, more insight in passive wing control, especially within high foldable structures, is gained.
The conventional quantitative method for the analysis of inorganic elements in polymer matrices is a complex and time consuming process that presents a significant risk for error. Typically, polymers are digested in a microwave oven or other devices under high temperature and pressure for several hours while employing different mixtures of high purity acids. In many cases, particularly when high concentrations of doped elements are present, the digestion is often incomplete and therefore the reproducibility depends strongly on the type of polymer and additives used. A promising alternative technology that allows for the direct analysis of these polymers without digestion is laser ablation ICP-MS. Due to a lack of available reference materials and the presence of matrix dependent effects, a precise calibration cannot be obtained. In order to compensate for the matrix dependent effects the use of internal standardization is necessary. In this study the correlation between the carbon released during the ablation process and the 13C signal detected by ICP-MS and its use as an internal standard are investigated. For this purpose, twenty-one virgin polymer materials are ablated; the released carbon is determined and correlated with the corresponding integrated 13C signal. The correlation resulted in a direct relationship between the ablated carbon and 13C signal demonstrating the potential ability to neglect at least some of the matrix dependent and transport effects which occur during the laser ablation of virgin polymers.