ABSTRACT
Aim: Until now, there have been no standardized guidelines for the content of infection control protocols. The aim of this research project is therefore to develop a standardized model for the evaluation and analysis of three dimensions: setting, protection targets, and precautions. Subject and methods: Events are part of social life and, as such, have a direct or indirect impact on the physical, mental, and social health of all involved groups (employees, artists, subcontractors, visitors, etc.). Valid infection control protocols for events must reduce the risk of infection in general, not only in a pandemic. A range of handouts and recommendations are available, mostly focusing on the visitors.For the present study, a total of 46 infection control protocols for events, hosted in the period between 2020 and 2021 in Germany, were analyzed from June to December 2021. The infection control protocols provide what was needed to realize events. Results: For the first time, a standardized model, called the Hygieia model, is presented for the evaluation and analysis of three dimensions: setting, protection targets of the involved groups, and precautions. Taking all three dimensions into account enables the assessment of existing pandemic safety protocols as well as the development of valid protocols in terms of effectiveness and efficiency. Conclusion: The Hygieia model can be used for risk assessment of events from conferences to concerts, especially for infection prevention under pandemic conditions.
ABSTRACT
Additive manufacturing (AM) allows the free form fabrication of three-dimensional (3D) structures with distinct external geometry, fitting into a patient-specific defect, and defined internal pore architecture. However, fabrication of predesigned collagen scaffolds using AM-based technologies is challenging due to the low viscosity of collagen solutions, gels or dispersions commonly used for scaffold preparation. In the present study, we have developed a straightforward method which is based on 3D plotting of a highly viscous, high density collagen dispersion. The swollen state of the collagen fibrils at pH 4 enabled the homogenous extrusion of the material, the deposition of uniform strands and finally the construction of 3D scaffolds. Stabilization of the plotted structures was achieved by freeze-drying and chemical crosslinking with the carbodiimide EDC. The scaffolds exhibited high shape and dimensional fidelity and a hierarchical porosity consisting of macropores generated by strand deposition as well as an interconnected microporosity within the strands as result of the freeze-drying process. Cultivation of human mesenchymal stromal cells on the scaffolds, with and without adipogenic or osteogenic stimulation, revealed their cytocompatibility and potential applicability for adipose and bone tissue engineering.