Understanding the inelastic response of collagen fibrils: A viscoelastic-plastic constitutive model.

Collagen fibrils, which are the lowest level fibrillar unit of organization of collagen, are thus of primary interest towards understanding the mechanical behavior of load-bearing soft tissues. The deformation of collagen fibrils shows unique mechanical features; namely, their high energy dissipation is even superior compared to most engineering materials. Additionally, there are indications that cyclic loading can further improve the toughness of collagen fibrils.

Alterations to the Gut Microbiome Impair Bone Strength and Tissue Material Properties.

Alterations in the gut microbiome have been associated with changes in bone mass and microstructure, but the effects of the microbiome on bone biomechanical properties are not known. Here we examined bone strength under two conditions of altered microbiota: (1) an inbred mouse strain known to develop an altered gut microbiome due to deficits in the immune system (the Toll-like receptor 5-deficient mouse [TLR5KO]); and (2) disruption of the gut microbiota (ΔMicrobiota) through chronic treatment with selected antibiotics (ampicillin and neomycin). The bone phenotypes of TLR5KO and WT (C57Bl/6) mice were examined after disruption of the microbiota from 4 weeks to 16 weeks of age as well as without treatment (n = 7 to 16/group, 39 animals total).