Digital Commons Network^™

A Study Of Aging In Male Cortical Bone Using Nanoindentation, Robert Christopher Singleton

Doctoral Dissertations

The incidence of bone fracture increases with age, due to both declining bone quantity and quality. Towards the goal of an improved understanding of the causes of the age-related decline in the fracture toughness of male cortical bone, nanoindentation experiments were performed on femoral diaphysis specimens from men aged 21-98 years and tibiae from male Fischer F344 rats aged 6, 12, and 24 months (n = 6-11 per age group). Bone is an anisotropic viscoelastic material with a complex hierarchical structure, in which water plays a critical mechanical role by conferring ductility. Because aged bone has been found to have …

Microrna-29 Family: A Positive Regulator Of Osteoclastogenesis, Henry Hrdlicka

Doctoral Dissertations

Osteoclasts are large multinucleated bone cells of the myeloid lineage. Osteoclasts secrete proteases and create an acidic environment, causing bone resorption. Osteoclast differentiation, driven by MCSF and RANKL, is tightly regulated by numerous factors, including microRNAs (miRNAs, miRs). miRNAs are short non-coding RNAs that post-transcriptionally regulate gene expression by binding to complementary mRNA sequences, leading to mRNA degradation or destabilization. The aim of these studies was to investigate the function of the miRNA-29-3p family in osteoclasts both in vivo and in vitro.

We generated mice which globally express a miR-29-3p tough decoy which competitively inhibits miR-29-3p activity. The examination …

Surgical Implant And Tissue Interface, Remigiusz Maciej Grzeskowiak

Doctoral Dissertations

Stability of implant-tissue interface is vital for implant integration with adjacent tissue and it influences directly short- and long-term surgical outcome. The literature provides comprehensive research on implants engaged in soft as well as in hard tissues. Various factors have been found to significantly influence the interface stability. This comprehensive work incorporated several research projects with main focus on implant-tissue interface stability, which was evaluated using biomechanical assessment tools such as pullout, four-point bending as well as reverse torque test. Implants were evaluated under ex vivo conditions, immediately after being placed within tissue as well as under in vivo conditions, …