Biomedical Engineering and Bioengineering Commons^™

Osteocyte Activity And Skeletal Muscle Relative Gene Expression Profiling After Short-Term Muscle Paralysis, Michelle Gelbs

Dissertations and Theses

Mechanical loading is essential for maintaining bone tissue. Reduced mechanical loading has been shown to have a negative effect on bone, and can result in the development of disuse osteoporosis. Disuse models of muscle inactivity and immobilization, like the Botox model used in this study, result in changes in the bone microarchitecture, the mechanisms behind which are not fully understood. In a previous four-week Botox disuse study, skeletally mature 20- week-old rats experienced degradation of intracortical bone, increased vascular porosity, and decreased osteocyte lacunar density in the tibiae. The focus of this study was to explicate a potential source of …

Diffuse Damage Repair Mechanism In Bone, Leila Mehraban Alvandi

Dissertations and Theses

Bone microdamage is a result of fatigue, creep or ‘wear and tear’ caused by physiological activities and largely contributes to bone fragility. Bone, unlike engineered materials, has the ability to repair the microscopic cracking or microdamage through targeted, osteoclast-mediated bone remodeling. This capability is crucial for preservation of its structural integrity and quality; failure of the skeleton to effectively repair microdamage leads to accumulation of damage, which is one of the main contributors to bone fragility. Linear microcracks (50-100 µm) and diffuse damage (Dif.Dx) (sub-micron) are the two types of microdamage. Recent studies show that Dif.Dx repairs without bone remodeling, …

Multi-Scale Assessment Of Bone Mechanics And The Mineral Phase Of Intramuscular Bone Of Atlantic Herring Fish, Svetlana Zeveleva

Dissertations and Theses

Bone tissue is a complex composite structure made up of a soft organic phase consisting of collagen I and non-collagenous proteins, and a hard inorganic phase consisting of mineral nanoplatelets. Given it’s compositional properties, bone is a unique stiff, tough, and strong biomaterial, making it exceptionally difficult to synthesize ex vivo. While the complete hierarchical structure may change with age and population, the basic building block components of mineralized collagen fibrils, are preserved. This study uses a model of intramuscular bone of the Atlantic herring fish, which present a simple structure, and no process of remodeling.

A multi-scale approach …

Bone Tissue Quality Determination Of Mice Through A Novel Reference Point Indentation Technique, Matin Lendhey

Dissertations and Theses

"Bone strength deteriorates with age; which increases the susceptibility to fracture. Current clinical techniques for the estimation of bone strength are largely Bone Mineral Density (BMD) based. However, toughness, which is the ability to resist crack growth, plays a critical role in bones‟ fracture resistance. Traditionally, toughness measurements involve large samples, obviating their use clinically. Recent data suggest that a reference point indentation approach provides a novel, localized measure of toughness from whole bones. In the current research, we evaluated the sensitivity of this method to discriminate small known differences in fracture toughness that exist between inbred mouse strains with …

Effects Of Estrogen Loss On The Vascular Porosity In Rat Cortical Bone, Jessica D Levy

Dissertations and Theses

"Osteoporosis is a skeletal disease that currently affects 10 million Americans, and is characterized by low bone mass and increased skeletal fragility (National Osteoporosis Foundation, 2011). Estrogen loss, which begins during menopause, is the leading cause of osteoporosis in women. Recent research has focused on changes in cortical bone microporosity due to estrogen loss, which is important for bone health; load-induced interstitial fluid flow within the lacunar-canalicular porosity surrounding osteocytes is thought to play an important role in bone maintenance, while the vascular porosity provides a pressure relaxation mechanism for the fluid flow in the lacunar-canalicular porosity. Recent high-resolution micro-CT …