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Biomedical Engineering Virtual Circuit Simulation Laboratories, Robert B. Szlavik

Biomedical Engineering

Circuit simulators, such as SPICE (Simulation Program with Integrated Circuit Emphasis) are useful tools that can enhance the educational experience of students in many subject areas within a biomedical engineering curriculum. Courses on biomedical instrumentation are venues for which virtual laboratory experiments, using circuit simulators, can be readily developed. The instructor can use the circuit simulation platform to illustrate relatively complex concepts, such as differential amplification, which have wide applicability to biomedical instrumentation. More advanced courses that focus on the physiology of excitable cells or neural modeling and simulation are also venues for which circuit simulators may be applied to …

Biomaterials Screening Experiment Using Sessile Drop Contact Angles, Lanny Griffin

Biomedical Engineering

No abstract provided.

Elastic Modulus Of Bone Using Ultrasonic Testing, Lanny Griffin, Victor Yu

Biomedical Engineering

No abstract provided.

Biomedical Engineering Simulation Using Visual Basic Macros In Micrsoft Excel, Lanny Griffin, Robert Crockett

Biomedical Engineering

No abstract provided.

Simulated Effects Of Marathon Training On Bone Density, Remodeling, And Microdamage Accumulation Of The Femur, Scott J. Hazelwood, Alesha B. Castillo

Biomedical Engineering

Stress fractures are mechanically induced injuries resulting from fatigue damage to bone due to repetitive loading and are common injuries occurring in runners. In this study, we used computer simulations of marathon training programs to examine the effects of endurance running on femoral density, remodeling, and microdamage accumulation. Simulated remodeling activity increased in the femoral neck and proximal cortex and predicted microdamage increased in all regions examined after 16 weeks for each program. Daily running for three years produced more microdamage than the advanced training schedule over the same time period. Areas of high remodeling and damage corresponded to clinically …

The Use Of Hinged External Fixation To Provide Additional Stabilization For Fractures Of The Distal Humerus, Christopher R. Deuel, Philip Wolinsky, Eric Shepherd, Scott Hazelwood

Biomedical Engineering

Objective: To assess improvements in fixation stability when a hinged unilateral external fixator is used to supplement compromised internal fixation for distal humerus fractures.

Methods: Removing a 1-cm section of the distal humerus in cadaveric whole-arm specimens created a comminuted distal humerus fracture model (AO type 13-A3). Fixation was then performed using different constructs representing optimal, compromised, or supplemented internal fixation. Internal fixation consisted of either 2 reconstruction plates with 1, 2, or 3 (optimal) distal attachment screws, or crossing medial and lateral cortical screws. A hinged external fixator was applied in combination with compromised internal fixation. The stability of …

Assessment Of Blood Vessel Mimics With Optical Coherence Tomography, Garret T. Bonnema, Kristen O'Halloran Cardinal, James B. Mcnally, Stuart K. Williams, Jennifer K. Barton

Biomedical Engineering

Optical coherence tomography (OCT) is an imaging mo-dality that enables assessment of tissue structural characteristics. Studies have indicated that OCT is a useful method to assess both blood vessel morphology and the response of a vessel to a deployed stent. We evaluated the ability of OCT to visualize the cellular lining of a tissue-engineered blood vessel mimic (BVM) and the response of this lining to a bare metal stent. We develop a side-firing endoscope that obtains intraluminal, longitudinal scans within the sterile bioreactor environment, enabling time-serial assessment. Seventeen BVMs are imaged with the endoscopic OCT system. The BVMs are then …

Quantitative Regional Associations Between Remodeling, Modeling, And Osteocyte Apoptosis And Density In Rabbit Tibial Midshafts, Nicole L. Hedgecock, Tamer Hadi, Andrew A. Chen, Shane B. Curtiss, R. Bruce Martin, Scott J. Hazelwood

Biomedical Engineering

Evidence suggests that osteocyte apoptosis is involved in the adaptive response of bone, although the specific role of osteocytes in the signaling mechanism is unknown. Here, we examined and correlated regional variability in indices of remodeling, modeling, osteocyte apoptosis, and osteocyte density in rabbit tibia midshafts. Histomorphometric analysis indicated that remodeling parameters (BMU activation frequency, osteon density, forming osteon density, and resorption cavity density) were lower in the cranial region compared to other quadrants. In addition, pericortical subregions displayed less remodeling relative to intracortical and endocortical ones. Modeling indices also demonstrated regional variability in that periosteal surfaces exhibited a greater …

Biomechanics Of The Rabbit Knee And Ankle: Muscle, Ligament, And Joint Contact Force Predictions, Dustin M. Grover, Andrew A. Chen, Scott J. Hazelwood

Biomedical Engineering

Mathematical models of small animals that predict in vivo forces acting on the lower extremities are critical for studies of musculoskeletal biomechanics and diseases. Rabbits are advantageous in this regard because they remodel their cortical bone similar to humans. Here, we enhance a recent mathematical model of the rabbit knee joint to include the loading behavior of individual muscles, ligaments, and joint contact at the knee and ankle during the stance phase of hopping. Geometric data from the hindlimbs of three adult New Zealand white rabbits, combined with previously reported intersegmental forces and moments, were used as inputs to the …

Volume Effects On Fatigue Life Of Equine Cortical Bone, R. F. Bigley, J. C. Gibeling, S. M. Stover, S. J. Hazelwood, D. P. Fyhrie, R. B. Martin

Biomedical Engineering

Materials, including bone, often fail due to loading in the presence of critical flaws. The relative amount, location, and interaction of these flaws within a stressed volume of material play a role in determining the failure properties of the structure. As materials are generally imperfect, larger volumes of material have higher probabilities of containing a flaw of critical size than do smaller volumes. Thus, larger volumes tend to fail at fewer cycles compared with smaller volumes when fatigue loaded to similar stress levels. A material is said to exhibit a volume effect if its failure properties are dependent on the …