The capacity to load bacteriophages into electrospun nanofibers of two representative biocompatible polymers has been evaluated, paying special attention to the possibility of preserving their antibacterial activity. Specifically, the work involves the following steps: (a) Evaluation of the effect of the applied electrical field on the phage activity; (b) evaluation of the activity when a lyophilization process could be avoided by using water soluble polymers (e.g., poly(ethylene glycol); (c) evaluation of the activity when dissolution of the polymer requires an organic solvent and lyophilization is theoretically necessary. In this case, a poly(ester urea) (PEU) derived from the natural L-leucine amino acid has been considered. Adsorption of commercial bacteriophage preparations into calcium carbonate particles was demonstrated to be a promising methodology to avoid lyophilization and keep the initial bactericide activity at a maximum. Phagestaph and Fersis bacteriophage commercial preparations have been selected for this study due to their specific activity against Staphylococci (e.g., S. aureus) and Streptococci (e.g., S. pyogenes) bacteria. Adhesion and proliferation assays using epithelial cells demonstrated the biocompatibility of both unloaded and bacteriophage-loaded PEU scaffolds, although some slight differences were observed depending on the type of bacteriophage and the selected preparation methodology.
This paper presents a novel calibration method for solid-state LiDAR devices based on a geometrical description of their scanning system, which has variable angular resolution. Determining this distortion across the entire Field-of-View of the system yields accurate and precise measurements which enable it to be combined with other sensors. On the one hand, the geometrical model is formulated using the well-known Snell’s law and the intrinsic optical assembly of the system, whereas on the other hand the proposed method describes the scanned scenario with an intuitive camera-like approach relating pixel locations with scanning directions. Simulations and experimental results show that the model fits with real devices and the calibration procedure accurately maps their variant resolution so undistorted representations of the observed scenario can be provided. Thus, the calibration method proposed during this work is applicable and valid for existing scanning systems improving their precision and accuracy in an order of magnitude.
The ELT M1 Local Coherencer is a non-contact metrology system aimed to simultaneously measure the relative pistons on the six sides of a target M1 segment with respect to neighboring ones (reference segments) with an accuracy below 300nm in a range of ±250μm. This measurement shall be performed while the Local Coherencer is supported by the M1 Segment Manipulator hanging from the M1 Segment Crane. IDOM has developed for the M1 Local Coherencer a lean, compact and robust solution featuring: - Six lightweight and compact Sensing Modules whose main system is a partially coherent light interferometer for the piston measurements that hugely simplifies image processing and avoids any ambiguity in the measurements. - Comprehensive and robust alignment detection and alignment compensation systems that ensure proper positioning and prevent apparent (bias) piston measurement errors. - A lean embodiment in which all the subsystems, including control and safety elements, are mounted on a single support structure and enclosed in the specified design volume, with no need to use the space reserved in the M1 Segment Manipulator - A solution largely based on small COTS and simple electronics, which account for ease of use, high reliability, easy replaceability and high durability of the system. This paper describes the proposed design as presented in the Preliminary Design Review (PDR) of the system held in May 2022.