Resume

• 2006

  Ph.D

  Developed mathematical formulations for analysis and design of ultrasound transducers and biosensors.

  Mechanical Engineering

  West Virginia University

  Advanced Calculus

  Advanced Mechanics of Materials

  Experimental Stress Analysis

  Medical Image Analysis

  Biomedical Ultrasound

• 2002

  English

  Spanish

  M.Sc

  Developed models to describe the mechanical behavior of articular cartilage.

  Mechanical Engineering

  Universidad del Valle

• 1996

  B.S

  Mechanical Engineering

  Universidad del Valle

• Composites

  Mechanical Testing

  Mathematical Modeling

  Biomechanics

  Matlab

  Medical Imaging

  Bioengineering

  Modeling

  Numerical Analysis

  Wave Propagation

  Mechanical Engineering

  Computational Mechanics

  Magnetic Resonance Elastography

  Solid Mechanics

  Fracture Mechanics

  Image Processing

  Fortran

  Finite Element Analysis

  Biomedical Engineering

  Image Analysis

  Nucleus pulposus cells synthesize a functional extracellular matrix and respond to inflammatory cytokine challenge following long term agarose culture

  George Dodge

  Robert Mauck

  Syrena Horava

  Nandan Nerurkar

  Joseph Chairo

  Nucleus pulposus cells synthesize a functional extracellular matrix and respond to inflammatory cytokine challenge following long term agarose culture

  This study shows how age affects the elastic properties at different locations in the annulus fibrosus. It was found that age tend to increase the stiffness of the tissue

  and the stiffness at the outer-anterior region of the annulus is higher than other locations.

  Mechanical Properties of the Extra-Fibrillar Matrix of Human Annulus Fibrosus are Location and Age Dependent

  Elizabeth Soulas

  Changes in tendon viscoelastic properties are observed after injuries and during healing as a \nproduct of altered composition and structure. Continuous Shear Wave Elastography is a new \ntechnique measuring viscoelastic properties of soft tissues using external shear waves. Tendon \nhas not been studied with this technique

  therefore

  the aims of this study were to establish the \nrange of shear and viscosity moduli in healthy Achilles tendons

  determine bilateral differences \nof these parameters and explore correlations of viscoelasticity to plantar flexion strength and \ntendon area. Continuous Shear Wave Elastography was performed over the free portion of both \nAchilles tendons from 29 subjects. Isometric plantar flexion strength and cross sectional area \nwere measured. The average shear and viscous moduli was 83.2kPa and 141.0Pa-s

  respectively. \nNo correlations existed between the shear or viscous modulus and area or strength. This \nindicates that viscoelastic properties can be considered novel

  independent biomarkers. The \nshear and viscosity moduli were bilaterally equivalent (p=0.013

  0.017) which allows determining \npathologies through side-to-side deviations. The average bilateral coefficient of variation was \n7.2% and 9.4% for shear and viscosity modulus

  respectively. The viscoelastic properties of the \nAchilles tendon may provide an unbiased

  non-subjective rating system of tendon recovery and \noptimizing treatment strategies.

  Viscoelastic properties of healthy Achilles tendon are independent of isometric plantar flexion strength and cross-sectional area

  Osama Mukdadi

  Elastic Guided Wave Propagation in a Periodic Array of Multi-Layered Piezoelectric Plates with Finite Cross-Sections

  Louis Soslowsky

  Biaxial Tensile Testing and Constitutive Modeling of Human Supraspinatus Tendon

  Osama Mukdadi

  Non-Invasive Assessment of Human Jawbone Using Ultrasonic Guided Waves

  Jose J. Garcia

  Analytic Solution for the Indentation of a Transversely Isotropic Elastic Layer Bonded to a Rigid Foundation

  Dawn Elliott

  Thomas Buchanan

  Viscoelastic mechanical properties are frequently altered after tendon injuries and during recovery. Therefore

  non-invasive measurements of shear viscoelastic properties may help evaluate tendon recovery and compare the effectiveness of different therapies. The objectives of this study were to describe an elastography method for measuring localized viscoelastic properties of tendons and to discuss the initial results in healthy and injured human Achilles and semitendinosus tendons. The technique used an external actuator to generate the shear waves in the tendon at different frequencies and plane wave imaging to measure shear wave displacements. For each of the excitation frequencies

  maps of direction-specific wave speeds were calculated using local frequency estimation. Maps of viscoelastic properties were obtained using a pixel-wise curve fit of wave speed and frequency. The method was validated by comparing measurements of wave speed in agarose gels with those obtained using magnetic resonance elastography. Measurements in human healthy Achilles tendons revealed a pronounced increase in wave speed as a function of frequency

  which highlights the importance of tendon viscoelasticity. Additionally

  the viscoelastic properties of the Achilles tendon were larger than those reported for other tissues. Measurements in a tendinopathic Achilles tendon indicated that it is feasible to quantify local viscoelastic properties. Similarly

  measurement in the semitendinosus tendon revealed substantial differences in viscoelastic properties between the healthy and contralateral tendons. Consequently

  this technique has the potential to evaluate localized changes in tendon viscoelastic properties caused by injury and during recovery in a clinical setting.

  Continuous shear wave elastography: A new method to measure viscoelastic properties of tendon in vivo

  Edward J. Vresilovic

  Validation and application of an intervertebral disc finite element model utilizing independently constructed tissue-level constitutive formulations that are nonlinear

  anisotropic

  and time-dependent

  The orientation of collagen fibers plays an important role on the mechanics of connective tissues. Connective tissues have fibers with different orientation distributions. The angular integration formulation used to model the mechanics of fibers with distributed orientation is accurate

  but computationally expensive for numerical methods such as finite elements. This study presents a formulation based on pre-integrated Generalized High-Order Structure Tensors (GHOST) which greatly improves the accuracy of the predicted stress. Simplifications of the GHOST formulation for transversely-isotropic and planar fiber distributions are also presented. Additionally

  the GHOST and the angular integration formulations are compared for different loading conditions

  fiber orientation functions

  strain energy functions and degrees of fiber non-linearity. It was found that the GHOST formulation predicted the stress of the fibers with an error lower than 10% for uniaxial and biaxial tension. Fiber non-linearity increased the error of the GHOST formulation; however

  the error was reduced to negligible values by considering higher order structure tensors. The GHOST formulation produced lower errors when used with an elliptical fiber density function and a binomial strain energy function. In conclusion

  the GHOST formulation is able to accurately predict the stress of fibers with distributed orientation without requiring numerous integral calculations. Consequently

  the GHOST formulation may reduce the computational effort needed to analyze the mechanics of fibrous tissues with distributed orientations.

  Accurate Prediction of Stress in Fibers with Distributed Orientations Using Generalized High-Order Structure Tensors

  A Non-linear Viscohyperelastic Model for Articular Cartilage

  Jose J. Garcia

  A Non-linear Viscohyperelastic Model for Articular Cartilage

  Louis Soslowsky

  Evaluation of Affine Fiber Kinematics in Human Supraspinatus Tendon Using Quantitative Projection Plot Analysis

  Osama Mukdadi

  Resonance Frequencies of Piezoelectric Plates Surrounded by Solid and Fluid Half-Spaces

  Stiffness Reduction and Fracture Evolution of Oblique Matrix Cracks in Composite Laminates

  Jose J. Garcia

  A Biphasic Viscohyperelastic Fibril Reinforced Model for Articular Cartilage: Formulation and Comparison with Experimental Data

  Biaxial Tension of Fibrous Tissue: Using Finite Element Methods to Address Experimental Challenges Arising From Boundary Conditions and Anisotropy

  edward vresilovic

  nathan jacobs

  This study uses finite elements to show how griping techniques affect the accuracy of measurements obtained using biaxial testing.

  Biaxial Tension of Fibrous Tissue: Using Finite Element Methods to Address Experimental Challenges Arising From Boundary Conditions and Anisotropy

  Extra-fibrillar Matrix Mechanics of Annulus Fibrosus in Tension and Compression

  Extra-fibrillar Matrix Mechanics of Annulus Fibrosus in Tension and Compression

  A Mechanistic Model for Transverse Damage Initiation

  Evolution

  and Stiffness Reduction in Laminated Composites

  Osama Mukdadi

  Dispersion Behavior of Elastic Guided Wave Propagation in Infinite Multilayered Piezoelectric Plates with Inversion Layer

  This study shows the application of Magnetic Resonance Elastography (MRE) as a tool for the non-invasive measurement of mechanical properties in the intervertebral disc. MRE showed higher sensitivity to degeneration compared to other imaging techniques.

  The Shear Modulus of the Nucleus Pulposus Measured Using MR Elastography: A Potential Biomarker for Intervertebral Disc Degeneration

  Daniel

  Cortes

  University of Pennsylvania

  West Virginia University

  University of Delaware

  Universidad del Valle

  Penn State University

  Development of clinical techniques for diagnosis and evaluation of injuries and degenerative diseases in orthopaedic tissues.

  University of Delaware

  University of Delaware

  Newark

  DE

  Diagnosis of intervertebral disc degeneration using mechanical properties as biomarkers

  Postdoctoral Fellow

  Teaching basic and advanced courses in mechanical engineering

  \nConducting research on cartilage mechanics and modeling.

  Universidad del Valle

  Graduate Research Assistant

  Analysis of piezoelectric and elastic structures using guided waves.

  West Virginia University

  Graduate Research Assistant

  Solid mechanics with applications to bioengineering.

  Universidad del Valle

  Penn State University

  Development of clinical techniques for diagnosis and evaluation of injuries and degenerative diseases in orthopaedic tissues.

  Assistant Professor

  State College

  Pennsylvania Area

  Modeling of fiber-reinforced tissues

  \nMagnetic Resonance Elastography

  University of Pennsylvania