ABSTRACT
Wheelchair fencing is an opposition sport on a specific wheelchair, with a fixed distance between the two athletes. As for other Paralympic sports, different categories exist for the different pathologies of the athletes. Searching for biomechanical performance criteria is of primary interest for coaches, recruiters and trainers. Such performance criteria have been highlighted for able-bodied fencers but not for para-fencers. Through transposition, the corresponding parameters for para-fencers would be the weapon speed and the ability to move the trunk forward and backward on their wheelchair. Therefore, the objective of this study was to determine performance criteria for para-fencers. Eleven French para-fencers performed fencing activities with a motion capture system while facing each other, with their own equipment. Different activities were realised to quantify the allonge, the weapon speed, and the torso motion. Only the correlation between the range of motion of the torso and the mass of the athletes wielding an épée was significant (p=0.02). The comparison between the different categories showed significant differences for the torso motion, which was not found for the weapon speed. Future studies, with a larger cohort, might help validate, or not, tendencies found in this study.
ABSTRACT
Understanding the interactions between biofilm and cementitious materials in biogas production systems is an essential step toward the development of durable concrete for this expanding sector. Although the action of the liquid phase medium on the material has been the subject of several research studies, the possible impact of the material's properties on biofilm formation and composition has been little investigated, if at all. The aim of this paper is to evaluate the characteristics of the biofilm according to the surface properties of the materials. Four cementitious materials with different chemical and mineralogical compositions, and various topological surface characteristics (pastes of CEM I, CEM III/C and CAC, and CEM I paste treated with oxalic acid) were exposed to the liquid phase of a fermenting biowaste for 10 weeks. The steps of biofilm formation were observed using SEM. Even though all the cementitious material surfaces were intensely colonized at the end of the experiments, the establishment of the biofilm seems to have been delayed on the oxalate-treated CEM I and on CAC coupons. Roughness and surface pH effects were not of prime importance for the biofilm development. The analysis of bacterial population diversity using 16S rDNA sequencing showed a less diversified microbial flora in the biofilm than in the reaction medium.
