Acta of bioengineering and biomechanics最新文献

Purpose: Acute ankle sprain may affect ankle function during sport and daily activities. This study aimed to use vector coding technique to analyze the difference over time between injured and healthy lower limb during the first week of acute ankle sprain phase (P1) and post a 1-month recovery phase (P2) to understand the return-to-play coordination strategy in the lower extremity. Methods: Six females attended the gait experiments with attached 40 reflective markers using eight-camera Vicon motion capture system. All participants walked barefoot while turning in four directions (T0°, T45°, T90°, T135°) at their self-selected speed. Coordination patterns were classified as in-phase, anti-phase, proximal or distal dominancy between lower limb joints involving hip, knee, ankle, subtalar, metatarsophalangeal (MTP) joint and tarsometatarsal (TMT) joint. Results: P1 showed more proximal joint dominant in Hip-Knee coupling angles but P2 displayed more distal joint dominant in Knee-Ankle joint coordination pattern and mainly distal joint dominant in Ankle-MTP coupling angle mapping. The Ankle-TMT1 and Ankle-TMT5 coordination patterns matched best in straight walking but worst in T135 walking. Conclusions: Investigating inter-segmental coordination in different turning movements could provide insights into gait changes from acute ankle sprain from one-month return-to-play recovery. Knowledge of lower limb coordination pattern may provide clinical implications to improve dynamic balance and gait stability for individuals with acute ankle sprain.

Purpose: This study investigated the influence of three types of metallic microfillers, spherical silver and spherical, and dendritic copper, on the ability of polyamide 12 (PA12) to inhibit microorganism growth on the surfaces of samples produced using laser-based powder bed fusion of polymers (PBF-LB/P). The aim of this study was to initially characterize these materials regarding their potential applicability for parts dedicated to use in the hospitals, where surfaces are periodically disinfected using chemical and/or physical measures. Methods: Composite powders with filler concentrations of 0.5, 1, 2 and 5% by weight were prepared using the mechanical mixing method and processed using PBF-LB/P. Three common hospital pathogens responsible for healthcare-associated infections: Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans were tested. Additionally, the safety of the composites was assessed through in vitro tests using human cell lines: keratinocytes and fibroblasts. Results: The research reveals that addition of copper or silver causes decrease in bacterial colony viability compared to the material without a filler, but an insignificant effect on antifungal properties. There was no significant impact within the tested range of filler's content on the antibacterial properties. Furthermore, a strong effect of the microfillers on tested material's toxicity is observed. Conclusions: The addition of metallic microfillers enhances the antibacterial response of polymeric materials processed with PBF-LB/P. Nevertheless, the observed varying levels of cytotoxicity toward eukaryotic cell lines underscore the need for further studies on the analysed materials to unequivocally determine their potential applicability as materials for short-term contact with human skin in a hospital setting.