Biomedical Engineering and Bioengineering Commons^™

Vision And Radar Steering Reduces Agricultural Sprayer Operator Stress Without Compromising Steering Performance, Travis A. Burgers, Kelly J. Vanderwerff

Mechanical Engineering Faculty Publications

Self-propelled agricultural sprayer operators work an average of 15 h d^-1 in peak season, and steering is the task that causes the operator the most stress because of the large number of stimuli involved. Automatic guidance systems help reduce stress and fatigue for operators by allowing them to focus on tasks other than steering. Physiological signals like skin conductance (electrodermal activity, EDA) change with stress and can be used to identify stressful events. The objective of this study was to determine if using a commercially available vision and radar guidance system (VSN®, Raven Industries) reduces agricultural sprayer operators’ stress …

Spark Plasma Sintering Of Low Modulus Titanium-Niobium-Tantalum-Zirconium (Tntz) Alloy For Biomedical Applications, Nicholas Mavros, Taban Larimian, Javier Esqivel, Rajeev Kumar Gupta, Rodrigo Contieri, Tushar Borkar

Mechanical Engineering Faculty Publications

In metallurgy, titanium has been a staple for biomedical purposes. Its slow toxicity and alloying versatility make it an attractive choice for medical applications. However, studies have shown the difference in elastic modulus between titanium alloys (116 GPa) and human bone (10–40 GPa), which contributes to long term issues with loose hardware fixation. Additionally, long term studies have shown elements such as vanadium and aluminum, which are commonly used in Ti-6Al-4V biomedical alloys, have been linked to neurodegenerative diseases like Alzheimer and Parkinson. Alternative metals known to be less toxic are being explored as replacements for alloying elements in titanium …

Compensation For Inertial And Gravity Effects In A Moving Force Platform, Sandra K. Hnat, Ben J.H. Van Basten, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

Force plates for human movement analysis provide accurate measurements when mounted rigidly on an inertial reference frame. Large measurement errors occur, however, when the force plate is accelerated, or tilted relative to gravity. This prohibits the use of force plates in human perturbation studies with controlled surface movements, or in conditions where the foundation is moving or not sufficiently rigid. Here we present a linear model to predict the inertial and gravitational artifacts using accelerometer signals. The model is first calibrated with data collected from random movements of the unloaded system and then used to compensate for the errors in …

Computational Sensitivity Investigation Of Hydrogel Injection Characteristics For Myocardial Support, Hua Wang, Christopher B. Rodell, Madonna E. Lee, Neville N. Dusaj, Joseph H. Gorman Iii, Jason A. Burdick, Robert C. Gorman, Jonathan F. Wenk

Mechanical Engineering Faculty Publications

Biomaterial injection is a potential new therapy for augmenting ventricular mechanics after myocardial infarction (MI). Recent in vivo studies have demonstrated that hydrogel injections can mitigate the adverse remodeling due to MI. More importantly, the material properties of these injections influence the efficacy of the therapy. The goal of the current study is to explore the interrelated effects of injection stiffness and injection volume on diastolic ventricular wall stress and thickness. To achieve this, finite element models were constructed with different hydrogel injection volumes (150 µL and 300 µL), where the modulus was assessed over a range of 0.1 kPa …

High Resolution Imaging Of The Mitral Valve In The Natural State With 7 Tesla Mri, Sam E. Stephens, Serguei Liachenko, Neil B. Ingels, Jonathan F. Wenk, Morten O. Jensen

Mechanical Engineering Faculty Publications

Imaging techniques of the mitral valve have improved tremendously during the last decade, but challenges persist. The delicate changes in annulus shape and papillary muscle position throughout the cardiac cycle have significant impact on the stress distribution in the leaflets and chords, thus preservation of anatomically accurate positioning is critical. The aim of this study was to develop an in vitro method and apparatus for obtaining high-resolution 3D MRI images of porcine mitral valves in both the diastolic and systolic configurations with physiologically appropriate annular shape, papillary muscle positions and orientations, specific to the heart from which the valve was …

Finite Element Simulation And Additive Manufacturing Of Stiffness-Matched Niti Fixation Hardware For Mandibular Reconstruction Surgery, Ahmadreza Jahadakbar, Narges Shayesteh Moghaddam, Amirhesam Amerinatanzi, David Dean, Haluk E. Karaca, Mohammad Elahinia

Mechanical Engineering Faculty Publications

Process parameters and post-processing heat treatment techniques have been developed to produce both shape memory and superelastic NiTi using Additive Manufacturing. By introducing engineered porosity, the stiffness of NiTi can be tuned to the level closely matching cortical bone. Using additively manufactured porous superelastic NiTi, we have proposed the use of patient-specific, stiffness-matched fixation hardware, for mandible skeletal reconstructive surgery. Currently, Ti-6Al-4V is the most commonly used material for skeletal fixation devices. Although this material offers more than sufficient strength for immobilization during the bone healing process, the high stiffness of Ti-6Al-4V implants can cause stress shielding. In this paper, …

Biomechanical Evaluation Of Fracture Fixation Constructs Using A Variable-Angle Locked Periprosthetic Femur Plate System, Martin F. Hoffmann, Travis A. Burgers, James J. Mason, Bart O. Williams, Debra L. Sietsema

Mechanical Engineering Faculty Publications

Background
In the United States there are more than 230,000 total hip replacements annually, and periprosthetic femoral fractures occur in 0.1–4.5% of those patients. The majority of these fractures occur at the tip of the stem (Vancouver type B1). The purpose of this study was to compare the biomechanically stability and strength of three fixation constructs and identify the most desirable construct.
Methods
Fifteen medium adult synthetic femurs were implanted with a hip prosthesis and were osteotomized in an oblique plane at the level of the implant tip to simulate a Vancouver type B1 periprosthetic fracture. Fractures were fixed with …

The Biomechanical Role Of Scaffolds In Augmented Rotator Cuff Tendon Repairs, Amit Aurora, Jesse A. Mccarron, Antonie J. Van Den Bogert, Jorge E. Gatica, Joseph P. Iannotti, Kathleen A. Derwin

Mechanical Engineering Faculty Publications

Background

Scaffolds continue to be developed and used for rotator cuff repair augmentation; however, the appropriate scaffold material properties and/or surgical application techniques for achieving optimal biomechanical performance remains unknown. The objectives of the study were to simulate a previously validated spring-network model for clinically relevant scenarios to predict: (1) the manner in which changes to components of the repair influence the biomechanical performance of the repair and (2) the percent load carried by the scaffold augmentation component.

Materials and methods

The models were parametrically varied to simulate clinically relevant scenarios, namely, changes in tendon quality, altered surgical technique(s), and …

Simulation Of Lower Limb Axial Arterial Length Change During Locomotion, Melissa D. Young, Matthew C. Streicher, Richard J. Beck, Antonie J. Van Den Bogert, Azita Tajaddini, Brian L. Davis

Mechanical Engineering Faculty Publications

The effect of external forces on axial arterial wall mechanics has conventionally been regarded as secondary to hemodynamic influences. However, arteries are similar to muscles in terms of the manner in which they traverse joints, and their three-dimensional geometrical requirements for joint motion. This study considers axial arterial shortening and elongation due to motion of the lower extremity during gait, ascending stairs, and sitting-to-standing motion. Arterial length change was simulated by means of a graphics based anatomic and kinematic model of the lower extremity. This model estimated the axial shortening to be as much as 23% for the femoropopliteal arterial …

Robotic Testing Of Proximal Tibio-Fibular Joint Kinematics For Measuring Instability Following Total Knee Arthroplasty, Wael K. Barsoum, Ho H. Lee, Trevor G. Murray, Robb Colbrunn, Alison K. Klika, S. Butler, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

Pain secondary to instability in total knee arthroplasty (TKA) has been shown to be major cause of early failure. In this study, we focused on the effect of instability in TKA on the proximal tibio-fibular joint (PTFJ). We used a robotics model to compare the biomechanics of the PTFJ in the native knee, an appropriately balanced TKA, and an unbalanced TKA. The tibia (n = 5) was mounted to a six-degree-of-freedom force/torque sensor and the femur was moved by a robotic manipulator. Motion at the PTFJ was recorded with a high-resolution digital camera system. After establishing a neutral position, …

Time Dependent Fixation And Implantation Forces For A Femoral Knee Component: An In Vitro Study, Travis A. Burgers, Jim Mason, Matthew Squire, Heidi-Lynn Ploeg

Mechanical Engineering Faculty Publications

Implant survival rate is a primary concern for individuals receiving a primary total knee arthroplasty. Loosening is the primary reason for revision surgery and was therefore the focus of the current study. To better understand the mechanics of implant fixation, the time-dependent fixation of a femoral knee component was measured in vitro on three cadaveric femurs. The fixation of each femoral knee component was measured with strain gauged implants for at least 10 minutes on each femoral component. Additionally, impaction forces were measured during the implantation of each component. These forces were 2–6 times less than previously reported. The implantation …

Personal Navigation Via High-Resolution Gait-Corrected Inertial Measurement Units, Özkan Bebek, Michael A. Suster, Srihari Rajgopal, Michael J. Fu, Xuemei Huang, M. Cenk Çavu¸So˘Glu,, Darrin J. Young, Mehran Mehregany, Antonie J. Van Den Bogert, Carlos H. Mastrangelo

Mechanical Engineering Faculty Publications

In this paper, a personal micronavigation system that uses high-resolution gait-corrected inertial measurement units is presented. The goal of this paper is to develop a navigation system that uses secondary inertial variables, such as velocity, to enable long-term precise navigation in the absence of Global Positioning System (GPS) and beacon signals. In this scheme, measured zerovelocity duration from the ground reaction sensors is used to reset the accumulated integration errors from accelerometers and gyroscopes in position calculation. With the described system, an average position error of 4 m is achieved at the end of half-hour walks.

An Analytical Model For Rotator Cuff Repairs, A. Aurora, Jorge E. Gatica, Antonie J. Van Den Bogert, J. A. Mccarron, Kathleen A. Derwin

Mechanical Engineering Faculty Publications

Background

Currently, natural and synthetic scaffolds are being explored as augmentation devices for rotator cuff repair. When used in this manner, these devices are believed to offer some degree of load sharing; however, no studies have quantified this effect. Furthermore, the manner in which loads on an augmented rotator cuff repair are distributed among the various components of the repair is not known, nor is the relative biomechanical importance of each component. The objectives of this study are to (1) develop quasi-static analytical models of simplified rotator cuff repairs, (2) validate the models, and (3) predict the degree of load …

Post-Yield Relaxation Behavior Of Bovine Cancellous Bone, Travis A. Burgers, Roderic S. Lakes, Sylvana Garcia-Rodriguez, Geoffrey R. Piller, Heidi-Lynn Ploeg

Mechanical Engineering Faculty Publications

Relaxation studies were conducted on specimens of bovine cancellous bone at post-yield strains. Stress and strain were measured for 1000 s and the relaxation modulus was determined. Fifteen cylindrical, cancellous bone specimens were removed from one bovine femur in the anterior–posterior direction. The relaxation modulus was found to be a function of strain. Therefore cancellous bone is non-linearly viscoelastic/viscoplastic in the plastic region. A power law regression was fit to the relaxation modulus data. The multiplicative constant was found to be statistically related through a power law relationship to both strain (p < 0.0005) and apparent density (p < 0.0005) while the power coefficient was found to be related through a power law relationship, E(t, ε)= A(ε)t-n(ε), to strain (p < 0.0005), but not apparent density.

A Real-Time, 3-D Musculoskeletal Model For Dynamic Simulation Of Arm Movements, Edward K. Chadwick, Dimitra Blana, Antonie J. Van Den Bogert, Robert F. Kirsch

Mechanical Engineering Faculty Publications

Neuroprostheses can be used to restore movement of the upper limb in individuals with high-level spinal cord injury. Development and evaluation of command and control schemes for such devices typically require real-time, ldquopatient-in-the-looprdquo experimentation. A real-time, 3-D, musculoskeletal model of the upper limb has been developed for use in a simulation environment to allow such testing to be carried out noninvasively. The model provides real-time feedback of human arm dynamics that can be displayed to the user in a virtual reality environment. The model has a 3-DOF glenohumeral joint as well as elbow flexion/extension and pronation/supination and contains 22 muscles …

Comment On "Quadriceps Protects The Anterior Cruciate Ligament", Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

No abstract provided.