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Full-Text Articles in Biomedical Engineering and Bioengineering

Emg-Driven Inverse Dynamic Analysis Of Knee Contact Forces During Gait And Cycling Using Opensim, Megan V. Pottinger, Katherine Mavrommati, Scott Hazelwood, Stephen M. Klisch Jun 2017

Emg-Driven Inverse Dynamic Analysis Of Knee Contact Forces During Gait And Cycling Using Opensim, Megan V. Pottinger, Katherine Mavrommati, Scott Hazelwood, Stephen M. Klisch

Biomedical and General Engineering

Joint contact forces determine the loading experienced by cartilage tissue and, thus, may be used to predict risk of cartilage tissue damage and osteoarthritis (OA). Participating in low impact and/or non-weight bearing activities such as cycling may help reduce knee OA risk by limiting forces exerted during exercise [1]. Cycling is a common recommendation for rehabilitative or fitness sustainment exercise for select patients [1]. Although knee joint contact forces have been directly measured in gait and cycling using instrumented knee implants [2,3] and calculated in gait using EMG-driven analysis [4]; they have not been calculated in cycling using ...


Knee Biomechanics During Cycling Are Similar For Normal Weight And Obese Subjects, Juan D. Gutierrez-Franco, Jordan Skaro, Scott Hazelwood, Stephen M. Klisch Jun 2017

Knee Biomechanics During Cycling Are Similar For Normal Weight And Obese Subjects, Juan D. Gutierrez-Franco, Jordan Skaro, Scott Hazelwood, Stephen M. Klisch

Biomedical and General Engineering

Osteoarthritis (OA) is a degenerative disease of cartilage and bone tissue, and is linked to more than 70% of total hip and knee replacements [1]. In 1994 the direct and indirect costs of OA in the United States were $155 billion [2] and in 2006 OA resulted in approximately $10.5 billion in hospital charges [3]. Obesity is a risk factor for OA [1, 3, 4], likely due to increased knee loading [5, 6] and varus malalignment [7] in gait. Seated cycling has been recommended as a weight-loss exercise with lower knee loads than walking or jogging [8]. However, lack ...


Principal Component Analysis Of Gait And Cycling Experiments: Crosstalk Error Reduction And Corrected Knee Axes, Jordan Skaro, Harsh Goel, Scott Hazelwood, Stephen M. Klisch Jun 2017

Principal Component Analysis Of Gait And Cycling Experiments: Crosstalk Error Reduction And Corrected Knee Axes, Jordan Skaro, Harsh Goel, Scott Hazelwood, Stephen M. Klisch

Biomedical and General Engineering

Crosstalk is a leading source of error in motion analysis [1-2]. Due to incorrect flexion axis direction that develops from marker placement error, crosstalk results in a strong, anatomically incorrect correlation between flexion-extension (FE) and adduction-abduction (AA) motions [1-2]. Thus, crosstalk limits the ability of biomechanical models to reflect the “true” motion of the knee. Principal Component Analysis (PCA) has been proposed as a post-hoc correction for crosstalk in prior gait studies [1-2]; however, previous studies have not proposed a method to determine PCA corrected knee axes. Further, it is not clear how PCA should be implemented in motion analysis ...


Elbow And Shoulder Joint Torques Are Correlated With Body Mass Index But Not Game Pitch Count In Youth Baseball Pitchers, Jim Douglas Darke, Eshan M. Dandekar, Arnel Aguinaldo, Scott Hazelwood, Stephen M. Klisch Jun 2017

Elbow And Shoulder Joint Torques Are Correlated With Body Mass Index But Not Game Pitch Count In Youth Baseball Pitchers, Jim Douglas Darke, Eshan M. Dandekar, Arnel Aguinaldo, Scott Hazelwood, Stephen M. Klisch

Biomedical and General Engineering

The number of ulnar collateral ligament (UCL) reconstructive (i.e. “Tommy John”) surgeries performed on youth baseball pitchers have more than doubled since 2000 [1]. Routinely pitching while fatigued is considered a leading factor associated with UCL injuries; adolescent pitchers who had elbow or shoulder surgery were 36 times more likely to have routinely pitched with arm fatigue [1]. MLB/USA Baseball Pitch Smart guidelines limit 9-10 yr. old pitchers to a maximum 75 pitches per game, a figure based on long-term studies related to injury prevention [2]. Several studies have shown that pitching kinematics (e.g. elbow flexion/extension ...


Three-Dimensional Adult Cardiac Extracellular Matrix Promotes Maturation Of Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes, Ahsley H. Fong, Mónica Romero-López, Christopher M. Heylman, Mark Keating, David Tran, Agua Sobrino, Anh Q. Tran, Hiep H. Pham, Cristhian Fimbres, Paul D. Gershon, Elliot L. Botvinick, Steven C. George, Christopher C.W. Hughes Aug 2016

Three-Dimensional Adult Cardiac Extracellular Matrix Promotes Maturation Of Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes, Ahsley H. Fong, Mónica Romero-López, Christopher M. Heylman, Mark Keating, David Tran, Agua Sobrino, Anh Q. Tran, Hiep H. Pham, Cristhian Fimbres, Paul D. Gershon, Elliot L. Botvinick, Steven C. George, Christopher C.W. Hughes

Biomedical and General Engineering

Pluripotent stem cell-derived cardiomyocytes (CMs) have great potential in the development of new therapies for cardiovascular disease. In particular, human induced pluripotent stem cells (iPSCs) may prove especially advantageous due to their pluripotency, their self-renewal potential, and their ability to create patient-specific cell lines. Unfortunately, pluripotent stem cell-derived CMs are immature, with characteristics more closely resembling fetal CMs than adult CMs, and this immaturity has limited their use in drug screening and cell-based therapies. Extracellular matrix (ECM) influences cellular behavior and maturation, as does the geometry of the environment—twodimensional (2D) versus three-dimensional (3D). We therefore tested the hypothesis that ...


Automated Detection And Analysis Of Depolarization Events In Human Cardiomyocytes Using Madec, Agnieszka F. Szymanska, Christopher M. Heylman, Rupsa Datta, Enrico Gratton Jan 2016

Automated Detection And Analysis Of Depolarization Events In Human Cardiomyocytes Using Madec, Agnieszka F. Szymanska, Christopher M. Heylman, Rupsa Datta, Enrico Gratton

Biomedical and General Engineering

Optical imaging-based methods for assessing the membrane electrophysiology of in vitro human cardiac cells allow for non-invasive temporal assessment of the effect of drugs and other stimuli. Automated methods for detecting and analyzing the depolarization events (DEs) in image-based data allow quantitative assessment of these different treatments. In this study, we use 2-photon microscopy of fluorescent voltage-sensitive dyes (VSDs) to capture the membrane voltage of actively beating human induced pluripotent stem cell-derived cardiomyocytes (hiPS-CMs). We built a custom and freely available Matlab software, called MaDEC, to detect, quantify, and compare DEs of hiPS-CMs treated with the β-adrenergic drugs, propranolol and ...


Label-Free Imaging Of Metabolism And Oxidative Stress In Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes, Rupsa Datta, Christopher M. Heylman, Steven C. George, Enrico Gratton Jan 2016

Label-Free Imaging Of Metabolism And Oxidative Stress In Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes, Rupsa Datta, Christopher M. Heylman, Steven C. George, Enrico Gratton

Biomedical and General Engineering

In this work we demonstrate a label-free optical imaging technique to assess metabolic status and oxidative stress in human induced pluripotent stem cell-derived cardiomyocytes by two-photon fluorescence lifetime imaging of endogenous fluorophores. Our results show the sensitivity of this method to detect shifts in metabolism and oxidative stress in the cardiomyocytes upon pathological stimuli of hypoxia and cardiotoxic drugs. This non-invasive imaging technique could prove beneficial for drug development and screening, especially for in vitro cardiac models created from stem cell-derived cardiomyocytes and to study the pathogenesis of cardiac diseases and therapy.


Supervised Machine Learning For Classification Of The Electrophysiological Effects Of Chronotropic Drugs On Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes, Christopher Heylman, Rupsa Datta, Agua Sobrino, Steven George, Enrico Gratton Dec 2015

Supervised Machine Learning For Classification Of The Electrophysiological Effects Of Chronotropic Drugs On Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes, Christopher Heylman, Rupsa Datta, Agua Sobrino, Steven George, Enrico Gratton

Biomedical and General Engineering

Supervised machine learning can be used to predict which drugs human cardiomyocytes have been exposed to. Using electrophysiological data collected from human cardiomyocytes with known exposure to different drugs, a supervised machine learning algorithm can be trained to recognize and classify cells that have been exposed to an unknown drug. Furthermore, the learning algorithm provides information on the relative contribution of each data parameter to the overall classification. Probabilities and confidence in the accuracy of each classification may also be determined by the algorithm. In this study, the electrophysiological effects of β–adrenergic drugs, propranolol and isoproterenol, on cardiomyocytes derived ...


Using Opensim To Predict Knee Joint Moments During Cycling, Karim C. Dudum, Jake E. Deschamps, Juan D. Gutierrez-Franco, Luke I. Kraemer, Alejandro M. Gonzalez-Smith, Eshan M. Dandekar, S. J. Hazelwood, Stephen M. Klisch Jun 2015

Using Opensim To Predict Knee Joint Moments During Cycling, Karim C. Dudum, Jake E. Deschamps, Juan D. Gutierrez-Franco, Luke I. Kraemer, Alejandro M. Gonzalez-Smith, Eshan M. Dandekar, S. J. Hazelwood, Stephen M. Klisch

Biomedical and General Engineering

Cycling is a relatively low impact activity conventionally recommended as a rehabilitative or fitness sustaining exercise for patients at a high risk for knee osteoarthritis (OA) [1,2]. Expanding our understanding of knee joint loads is necessary to develop and improve evidence-based prescriptions for cycling as a rehabilitative and fitness therapy that limits the risk for knee OA.

OpenSim (www.simtk.org) is an open source biomechanical analysis software that can partition predictions of external joint loads (or net muscle moments) into muscle and joint contact loads [3]. Joint contact loads more accurately represent cartilage tissue loading and hence risk ...


Human Knee Joint Finite Element Model Using A Two Bundle Anterior Cruciate Ligament: Validation And Gait Analysis, Nicholas A. Czapla, Meghan K. Sylvia, Zachary F. Lerner, David J. Tuttle, Otto J. Schueckler, S. J. Hazelwood, Stephen M. Klisch Jun 2015

Human Knee Joint Finite Element Model Using A Two Bundle Anterior Cruciate Ligament: Validation And Gait Analysis, Nicholas A. Czapla, Meghan K. Sylvia, Zachary F. Lerner, David J. Tuttle, Otto J. Schueckler, S. J. Hazelwood, Stephen M. Klisch

Biomedical and General Engineering

Anterior cruciate ligament (ACL) deficient individuals are at a much higher risk of developing osteoarthritis (OA) compared to those with intact ACLs, likely due to altered biomechanical loading [1]. Research indicates the ACL is comprised of two “bundles”, the anteromedial (AM) and posterolateral (PL) bundles [2]. Although the function of both bundles is to restrain anterior tibial translation (ATT), each bundle has their own distinct range of knee flexion where they are most effective [3].

Articular cartilage contact stress measurements are difficult to measure in vivo. An alternative approach is to use knee joint finite element models (FEMs) to predict ...


Development Of A Human Knee Joint Finite Element Model To Investigate Cartilage Stress During Walking In Obese And Normal Weight Adults, Meghan K. Sylvia, Nicholas A. Czapla, Zachary F. Lerner, David J. Tuttle, Otto J. Schueckler, Scott Hazelwood, Stephen M. Klisch Jun 2015

Development Of A Human Knee Joint Finite Element Model To Investigate Cartilage Stress During Walking In Obese And Normal Weight Adults, Meghan K. Sylvia, Nicholas A. Czapla, Zachary F. Lerner, David J. Tuttle, Otto J. Schueckler, Scott Hazelwood, Stephen M. Klisch

Biomedical and General Engineering

Osteoarthritis (OA) is a degenerative condition characterized by the breakdown and loss of joint articular cartilage. While the cause of OA is not precisely known, obesity is a known risk factor [1]. Particular effort has gone towards understanding the relationship between obesity and knee OA because obesity is more strongly linked to OA at the knee than at any other lower extremity joint [2]. Although the relationship between obesity and knee OA is well established, the mechanism of pathogenesis is less understood. Excess body weight generates greater joint contact forces at the knee. However, obese individuals alter their gait, resulting ...


Design And Implementation Of An Instrumented Pedal For Cycling Biomechanics Research, Luke I. Kraemer, Juan D. Gutierrez-Franco, Jake E. Deschamps, Karim C. Dudum, Eshan M. Dandekar, Scott Hazelwood, Hemanth Porumamilla, Stephen M. Klisch Jun 2015

Design And Implementation Of An Instrumented Pedal For Cycling Biomechanics Research, Luke I. Kraemer, Juan D. Gutierrez-Franco, Jake E. Deschamps, Karim C. Dudum, Eshan M. Dandekar, Scott Hazelwood, Hemanth Porumamilla, Stephen M. Klisch

Biomedical and General Engineering

Cycling is a common, low-impact activity used for recreation, exercise, and rehabilitation. Knee joint loading can be predicted using inverse dynamic analyses of pedal load cell and kinematic data measured during cycling biomechanics experiments. Several studies have successfully measured foot loading at the pedals, e.g. by using custom instrumented pedal spindles outfitted with strain gauges and a potentiometer to measure crank angle [1-3]. Such designs are relatively complex, requiring difficult machining and component fabrication, and require post-processing of strain gauge data.

The long-term goal of this study is to calculate knee joint loading and, ultimately, cartilage tissue stress to ...


A Biomechanical Comparison Of Three Spondylolysis Repair Techniques In A Calf Spine Model, R. Roberto, B. Dezfuli, C. Deuel, S. Curtiss, S. Hazelwood Feb 2013

A Biomechanical Comparison Of Three Spondylolysis Repair Techniques In A Calf Spine Model, R. Roberto, B. Dezfuli, C. Deuel, S. Curtiss, S. Hazelwood

Biomedical and General Engineering

Summary of background data: Previous work has demonstrated the efficacy of lumbar pedicle screw hook rod (PSHR) techniques and the Buck screw in the stabilization of spondylolysis. The mechanical behavior of lower profile cervical implants used to create PSHR, hybrid cable plate constructs, and titanium miniplating has not previously been described.

Methods: Calf lumbar spines (L2-L6) were utilized for testing (n = 27). Intervertebral rotation was measured in the intact spines across the L4-5 segment before and after creation of bilateral pars interarticularis defects. Defects were then stabilized with one of three repair techniques, PSHR, miniplate, or cable plate (CP) constructs ...


The 4+1 Program And Distance Learning Meeting Objectives And Outcomes, Daniel W. Walsh, Lanny Griffin, Robert S. Crockett Jun 2011

The 4+1 Program And Distance Learning Meeting Objectives And Outcomes, Daniel W. Walsh, Lanny Griffin, Robert S. Crockett

Biomedical and General Engineering

Graduate engineering education is a key to the maintenance of U.S. competitiveness in the world market. The world has been an extremely dynamic engine during the last fifty years, and we have witnessed a dramatic change in the world order. The change has been evolutionary in many cases, but events in Eastern Europe, the Middle East and the erstwhile Soviet Union are only slightly less cataclysmic than the Second World War. In a world where strength is measured in terms of the financial resource, the technological ability and the intellectual capability of a populace Japan, China, India and the ...


Polymeric Splint And Rapid-Setting Polyurethane, Lanny Griffin, Dane Robert Jones Mar 2011

Polymeric Splint And Rapid-Setting Polyurethane, Lanny Griffin, Dane Robert Jones

Biomedical and General Engineering

A splint includes a first container capable of being wrapped about an item to be supported and a second container capable of containing a multiple part mixture during a mixing operation. The second container being capable of delivering the mixture into the first container, wherein the mixture hardens to form a support structure. A method for using the splint is also disclosed.


The Biomechanics Of Varied Proximal Locking Screw Configurations In A Synthetic Model Of Proximal Third Tibial Fracture Fixation, Philip R. Wolinsky, Douglas Dennis, Brett D. Crist, Shane Curtiss, Scott J. Hazelwood Mar 2011

The Biomechanics Of Varied Proximal Locking Screw Configurations In A Synthetic Model Of Proximal Third Tibial Fracture Fixation, Philip R. Wolinsky, Douglas Dennis, Brett D. Crist, Shane Curtiss, Scott J. Hazelwood

Biomedical and General Engineering

Objective: To determine if 1) angularly stable devices created by compressing (‘‘locking’’) proximal locking screws to intramedullary nails using end caps or compression screws or 2) increasing the number of proximal screws from two to three increases the stiffness of intramedullary constructs that stabilize proximal third tibia fractures in a nonosteopenic bone model.


Methods: Four proximal locking screw configurations were examined in a synthetic composite tibia model with a 2-cm gap simulating a comminuted proximal third tibia fracture with no bony contact: 1) two proximal screws not compressed to the nail; 2) one of two proximal screws compressed to the ...


The Effect Of Cox-2 Specific Inhibition On Direct Fracture Healing In The Rabbit Tibia, David J. Hak, Kurt S. Schulz, Behrang Khoie, Scott J. Hazelwood Jan 2011

The Effect Of Cox-2 Specific Inhibition On Direct Fracture Healing In The Rabbit Tibia, David J. Hak, Kurt S. Schulz, Behrang Khoie, Scott J. Hazelwood

Biomedical and General Engineering

Objective: The purpose of this study was to evaluate the effect of Cox-2 administration on direct (primary) fracture healing.

Methods: A transverse tibial osteotomy was created in adult male rabbits and rigidly fixed in compression using a 2.7-mm dynamic compression plate. Animals were randomized to receive either rofecoxib (12.5 mg orally per day) or placebo. Animals were killed at 4 weeks and fracture healing assessed by mechanical testing.

Results: There were no significant differences between the control and Cox-2 treated animals in terms of mechanical strength at 4 weeks. There was a high complication rate of peri-implant fractures ...


Arteriogenesis And Ischemia Impair Functional Vasodilation In Resistance Arteries, Trevor Cardinal, Joseph S. Zhu, Kyle R. Struthers, Thomas J. Kesler, Matthew D. Yocum Jan 2011

Arteriogenesis And Ischemia Impair Functional Vasodilation In Resistance Arteries, Trevor Cardinal, Joseph S. Zhu, Kyle R. Struthers, Thomas J. Kesler, Matthew D. Yocum

Biomedical and General Engineering

No abstract provided.


Differential Regulation Of Immature Articular Cartilage Compressive Moduli And Poisson's Ratios By In Vitro Stimulation With Igf-1 And Tgf-Β1, Gregory M. Williams, Kristin J. Dills, Christian R. Flores, Michael E. Stender, Kevin M. Stewart, Lauren M. Nelson, Albert C. Chen, Koichi Masuda, Scott J. Hazelwood, Stephen M. Klisch, Robert L. Sah Sep 2010

Differential Regulation Of Immature Articular Cartilage Compressive Moduli And Poisson's Ratios By In Vitro Stimulation With Igf-1 And Tgf-Β1, Gregory M. Williams, Kristin J. Dills, Christian R. Flores, Michael E. Stender, Kevin M. Stewart, Lauren M. Nelson, Albert C. Chen, Koichi Masuda, Scott J. Hazelwood, Stephen M. Klisch, Robert L. Sah

Biomedical and General Engineering

Mechanisms of articular cartilage growth and maturation have been elucidated by studying composition-function dynamics during in vivo development and in vitro culture with stimuli such as insulin-like growth factor-1 (IGF-1) and transforming growth factor-beta 1 (TGF-β1). This study tested the hypothesis that IGF-1 and TGF-β1 regulate immature cartilage compressive moduli and Poisson’s ratios in a manner consistent with known effects on tensile properties. Bovine calf articular cartilage from superficial-articular (S) and middle-growth (M) regions were analyzed fresh or following culture in medium with IGF-1 or TGF-β1. Mechanical properties in confined (CC) and unconfined (UCC) compression, cartilage matrix composition, and ...


Locked Plate Fixation Of Osteoporotic Humeral Shaft Fractures: Are Two Locking Screws Per Segment Enough?, David J. Hak, Peter Althausen, S J. Hazelwood Apr 2010

Locked Plate Fixation Of Osteoporotic Humeral Shaft Fractures: Are Two Locking Screws Per Segment Enough?, David J. Hak, Peter Althausen, S J. Hazelwood

Biomedical and General Engineering

Objective: The purpose of this study was to compare the biomechanical behavior of using two versus three locking screws per bone segment in a cadaveric humerus fracture gap model.

Methods: Six matched pairs of elderly osteoporotic fresh–frozen human cadaveric humerii were used. An eight-hole locking compression plate was placed posteriorly on the humeral shaft and secured with either four or six bicortical locking screws. A 5-mm middiaphyseal gap osteotomy was created to simulate a comminuted fracture without bony contact. Specimens were tested in offset axial compression, four-point anteroposterior bending, four-point medial– lateral bending, and torsion. After the initial testing ...


Morphological Assessment Of Basic Multicellular Unit Resorption Parameters In Dogs Shows Additional Mechanisms Of Bisphosphonate Effects On Bone, Matthew R. Allen, Antonia M. Erickson, Xiang Wang, David B. Burr, R. Bruce Martin, Scott J. Hazelwood Jan 2010

Morphological Assessment Of Basic Multicellular Unit Resorption Parameters In Dogs Shows Additional Mechanisms Of Bisphosphonate Effects On Bone, Matthew R. Allen, Antonia M. Erickson, Xiang Wang, David B. Burr, R. Bruce Martin, Scott J. Hazelwood

Biomedical and General Engineering

Bisphosphonates (BPs) slow bone loss by reducing initiation of new basic multicellular units (BMUs). Whether or not BPs simply prevent osteoclasts from initiating new BMUs that resorb bone or also reduce the amount of bone they resorb at the BMU level is not clear. The goal of this study was to determine the effects of BPs on three morphological parameters of individual BMUs, resorption depth (Rs.De), area (Rs.Ar), and width (Rs.Wi). After 1 year of treatment with vehicle (VEH), alendronate (ALN; 0.10, 0.20, or 1.00 mg/kg/day), or risedronate (RIS; 0.05, 0 ...


Impaired Vascular Reactivity Following Chronic Ischemia In The Arteries Of The Mouse Hindlimb, Trevor Cardinal, Thomas J. Kesler, Matthew D. Yocum, Tyler S. Smith, Nolan M. Mott Jan 2010

Impaired Vascular Reactivity Following Chronic Ischemia In The Arteries Of The Mouse Hindlimb, Trevor Cardinal, Thomas J. Kesler, Matthew D. Yocum, Tyler S. Smith, Nolan M. Mott

Biomedical and General Engineering

No abstract provided.


Compliance Calibration For Fracture Testing Of Anisotropic Biological Materials, J. A. Creel, S. M. Stover, R. B. Martin, D. P. Fyhrie, S. J. Hazelwood, J. C. Gibeling Oct 2009

Compliance Calibration For Fracture Testing Of Anisotropic Biological Materials, J. A. Creel, S. M. Stover, R. B. Martin, D. P. Fyhrie, S. J. Hazelwood, J. C. Gibeling

Biomedical and General Engineering

The compliance technique has been used to monitor crack length during fracture and fatigue testing of materials. Difficulties arise when this technique is applied to anisotropic biological materials such as bone. In this tutorial, two different methods of analyzing compliance calibration data are described: the standard ASTM method and a new approach developed by the authors specifically for anisotropic materials. An example is given showing how data from equine cortical bone can be analyzed. In this example, calibration tests were conducted on thirty-six three point bend specimens machined from the middiaphysis of six pairs of equine third metacarpal bones. Cracks ...


Material Properties Are Related To Stress Fracture Callus And Porosity Of Cortical Bone Tissue At Affected And Unaffected Sites, Rachel C. Entwistle,, Sara C. Sammons, Robert F. Bigley, Scott J. Hazelwood, David P. Fyhrie, Jeffery C. Gibeling, Susan M. Stover Oct 2009

Material Properties Are Related To Stress Fracture Callus And Porosity Of Cortical Bone Tissue At Affected And Unaffected Sites, Rachel C. Entwistle,, Sara C. Sammons, Robert F. Bigley, Scott J. Hazelwood, David P. Fyhrie, Jeffery C. Gibeling, Susan M. Stover

Biomedical and General Engineering

Stress fractures are overuse injuries of bone that affect elite athletes and military recruits. One response of cortical bone to stress fracture is to lay down periosteal callus. The objectives of this study were to determine if material properties are different among bones with different stages of stress fracture callus, at both a callus site and at a distal site. Cortical specimens were mechanically tested to determine their stress–strain response. Material property differences were examined using nonparametric and regression analyses. At the callus site, material properties were low during the earliest stages of callus, higher with increasing callus maturity ...


A Biomechanical Comparison Of Locked Plate Fixation With Percutaneous Insertion Capability Versus The Angled Blade Plate In A Subtrochanteric Fracture Gap Model, Brett D. Crist, Afshin Khalafi, Scott J. Hazelwood, Mark A. Lee Oct 2009

A Biomechanical Comparison Of Locked Plate Fixation With Percutaneous Insertion Capability Versus The Angled Blade Plate In A Subtrochanteric Fracture Gap Model, Brett D. Crist, Afshin Khalafi, Scott J. Hazelwood, Mark A. Lee

Biomedical and General Engineering

Objectives: The angled blade plate has been the historical standard in fixed-angle extramedullary subtrochanteric femur fracture fixation, but it requires an extensile lateral approach to the femur. Little formal evaluation exists for specifically designed percutaneous extramedullary implants. The purpose of this study was to compare 3 locked plating constructs, all with percutaneous insertion capability, with the standard 95-degree angled blade plate to determine whether specifically designed fixed-angle extramedullary implants for subtrochanteric femur fractures were biomechanically comparable to the angled blade plate.

Methods: Forty composite adult femurs were divided into 4 equal groups. The constructs evaluated included a 95-degree angled blade ...


A Modification To The Group Delay And Simulated Annealing Technique For Characterization Of Peripheral Nerve Fiber Size Distributions For Non-Deterministic Sampled Data, Robert B. Szlavik Sep 2009

A Modification To The Group Delay And Simulated Annealing Technique For Characterization Of Peripheral Nerve Fiber Size Distributions For Non-Deterministic Sampled Data, Robert B. Szlavik

Biomedical and General Engineering

The ability to determine the characteristics of peripheral nerve fiber size distributions would provide additional information to clinicians for the diagnosis of specific pathologies of the peripheral nervous system. Investigation of these conditions, using electro-diagnostic techniques, is advantageous in the sense that such techniques tend to be minimally invasive yet provide valuable diagnostic information. One of the principal electro-diagnostic tools available to the clinician is the nerve conduction velocity test. While the peripheral nerve conduction velocity test can provide useful information to the clinician regarding the viability of the nerve under study, it is a single parameter test that yields ...


A Simple, Yet Effective, Demonstration Of Polymeric Mechanical Behavior, Lanny Griffin, Jeffrey Swab Jun 2009

A Simple, Yet Effective, Demonstration Of Polymeric Mechanical Behavior, Lanny Griffin, Jeffrey Swab

Biomedical and General Engineering

Developing an appreciation for the mechanical behavior of polymers materials in a lecture mode can be challenging for students if they have not bad the benefit of a laboratory experience . We have developed a simp le demonstration of thermoplastic polymeric behav ior using low-density polyethylene bags. The demonstration illustrates strengthening, rate effects, and directionality of strengthening and stiffness. Following the demonstration, students are better ab le to articulate the influence of structure, properties, processing , and performance as it applies to thermoplastic polymers.


Theoretical Analysis Of Alendronate And Risedronate Effects On Canine Vertebral Remodeling And Microdamage, Xiang Wang, Antonia M. Erickson, Matthew R. Allen, David B. Burr, R. Bruce Martin, Scott J. Hazelwood May 2009

Theoretical Analysis Of Alendronate And Risedronate Effects On Canine Vertebral Remodeling And Microdamage, Xiang Wang, Antonia M. Erickson, Matthew R. Allen, David B. Burr, R. Bruce Martin, Scott J. Hazelwood

Biomedical and General Engineering

Bisphosphonates suppress bone remodeling activity, increase bone volume, and significantly reduce fracture risk in individuals with osteoporosis and other metabolic bone diseases. The objectives of the current study were to develop a mathematical model that simulates control and 1 year experimental results following bisphosphonate treatment (alendronate or risedronate) in the canine fourth lumbar vertebral body, validate the model by comparing simulation predictions to 3 year experimental results, and then use the model to predict potential long term effects of bisphosphonates on remodeling and microdamage accumulation. To investigate the effects of bisphosphonates on bone volume and microdamage, a mechanistic biological model ...


Functional Vasodilation Following Murine Chronic Hindlimb Ischemia, Matthew David Yocum, Trevor R. Cardinal Apr 2009

Functional Vasodilation Following Murine Chronic Hindlimb Ischemia, Matthew David Yocum, Trevor R. Cardinal

Biomedical and General Engineering

Abstract of conference presentation.


A Numerical Approach For Predicting The Impact Of Vascular Architecture On Blood Flow During Ischemic Repair, Stephanie Ann Wood, Shilpi Ghosh, Kevin Jones, Gabriel Gruionu, Trevor R. Cardinals Apr 2009

A Numerical Approach For Predicting The Impact Of Vascular Architecture On Blood Flow During Ischemic Repair, Stephanie Ann Wood, Shilpi Ghosh, Kevin Jones, Gabriel Gruionu, Trevor R. Cardinals

Biomedical and General Engineering

Abstract of conference presentation.