Biomedical Engineering and Bioengineering Commons^™

Comparison Of Failure Mechanisms For Cements Used In Skeletal Luting Applications, O. Clarkin, D. Boyd, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

Glass Polyalkenoate Cements (GPCs) based on strontium calcium zinc silicate (Sr-Ca-Zn-SiO₂) glasses and low molecular weight poly (acrylic acid) (PAA) have been shown to exhibit suitable compressive strength (65 MPa) and flexural strength (14 MPa) for orthopaedic luting applications. In this study, two such GPC formulations, alongside two commercial cements (Simplex ® P and Hydroset™) were examined. Fracture toughness and tensile bond strength to sintered hydroxyapatite and a biomedical titanium alloy were examined. Fracture toughness of the commercial Poly(methyl methacrylate) cement, Simplex® P, (3.02 MPa m^1/2) was superior to that of the novel GPC (0.36 MPa …

Development Of An Electroencephalography-Based Brain-Computer Interface Supporting Two-Dimensional Cursor Control, Dandan Huang

Theses and Dissertations

This study aims to explore whether human intentions to move or cease to move right and left hands can be decoded from spatiotemporal features in non-invasive electroencephalography (EEG) in order to control a discrete two-dimensional cursor movement for a potential multi-dimensional Brain-Computer interface (BCI). Five naïve subjects performed either sustaining or stopping a motor task with time locking to a predefined time window by using motor execution with physical movement or motor imagery. Spatial filtering, temporal filtering, feature selection and classification methods were explored. The performance of the proposed BCI was evaluated by both offline classification and online two-dimensional cursor …

Spatial Detection Of Multiple Movement Intentions From Sam-Filtered Single-Trial Meg For A High Performance Bci, Harsha Battapady

Theses and Dissertations

The objective of this study is to test whether human intentions to sustain or cease movements in right and left hands can be decoded reliably from spatially filtered single trial magneto-encephalographic (MEG) signals. This study was performed using motor execution and motor imagery movements to achieve a potential high performance Brain-Computer interface (BCI). Seven healthy volunteers, naïve to BCI technology, participated in this study. Signals were recorded from 275-channel MEG and synthetic aperture magnetometry (SAM) was employed as the spatial filter. The four-class classification for natural movement intentions was performed offline; Genetic Algorithm based Mahalanobis Linear Distance (GA-MLD) and direct-decision …

Fabrication And Characterization Of Bioactive, Composite Electrospun Bone Tissue Engineering Scaffolds Intended For Cleft Palate Repair, Parthasarathy Madurantakam

Theses and Dissertations

Tissue Engineering is a scientific discipline that aims to regenerate tissues and organs that are diseased, lost or congenitally absent. It encompasses the use of suitable synthetic equivalents of native extracellular matrix that may or may not be supplemented with cells or relevant growth factors. Such scaffolds are designed to reside at the site of implantation for a variable period of time during which they induce the regeneration of native tissue. During this time, they also provide a template for new cells to attach, infiltrate, differentiate into appropriate phenotype and eventually restore function of the concerned tissue. Among the factors …

Discriminating Pulmonary Hypertension Caused By Monocrotaline Toxicity From Chronic Hypoxia By Near-Infrared Spectroscopy And Multivariate Methods Of Analysis, Simon Duri, Robert C. Molthen, Chieu D. Tran

Biomedical Engineering Faculty Research and Publications

A new method has been developed for the determination of tissue pathology caused by chronic hypoxia and monocrotaline toxicity. The method is based on the use of near-infrared (NIR) spectrophotometry to measure spectra of lung tissue from normal chronic hypoxia (CH) and monocrotaline (MCT) models of pulmonary hypertension (PH), followed by analysis using multivariate methods, that is, principal component analysis (PCA) and partial least squares (PLS). Synergistic use of NIR with the PCA/PLS method makes it possible, for the first time, not only to divide different lung tissue samples into their respective groups (normal, CH, and MCT) but also to …

Computational Modeling Of The Helical Axis In The Human Knee--Detecting Changes In The Transverse Plane, Emily Carney

Theses and Dissertations

The purpose of this study was to build a helical axis algorithm capable of detecting changes in the helical axis intersection of the tibia and femur in human knees. This algorithm was designed and tested using three models: a multiplanar rigid body model, a mathematical model, and a cylinder model. The multiplanar rigid body model closely mimics knee movement without supporting ligamentous structures, thus the movement was unconstrained. In this model kinematic position data were collected using both MotionMonitor™ (MotionMonitor™ Version 7.7, Innovative Sports Training, Chicago, IL) and Vicon Nexus 1.3 software system (Oxford Metrics Group, Oxford, UK). To test …

Video-Rate Near Infrared Tomography To Image Pulsatile Absorption Properties In Thick Tissue, Zhiqiu Li, Venkataramanan Krishnaswamy, Scott C. Davis, Subhadra Srinivasan, Keith D. Paulsen, Brian W. Pogue

Dartmouth Scholarship

A high frame-rate near-infrared (NIR) tomography system was created to allow transmission imaging of thick tissues with spectral encoding for parallel source implementation. The design was created to maximize tissue penetration through up to 10 cm of tissue, allowing eventual use in human imaging. Eight temperature-controlled laser diodes (LD) are used in parallel with 1.5 nm shifts in their lasing wavelengths. Simultaneous detection is achieved with eight high-resolution, CCD-based spectrometers that were synchronized to detect the intensities and decode their source locations from the spectrum. Static and dynamic imaging is demonstrated through a 64 mm tissue-equivalent phantom, with acquisition rates …

Department Of Biological Systems Engineering Newsletter, Volume 5, Number 1, July 2009

BSE Department Magazine

No abstract provided.

Micro, Nano Encapsulation Methods For Sustained Release Drug Formulations And Biomimetic Applications, Shantanu Balkundi

Doctoral Dissertations

The Layer-by-Layer (LbL) assembly technique was used to obtain a new type of protein/polyphenol microcapsule based on naturally occurring polyphenol (-)-epigallocatechin gallate (EGCG) and gelatin, type A. The dependence of permeability on the molecular weight of permeating substances was studied and compared with commonly used polyallylamine/polystyrene sulfonate capsules. A quartz crystal microbalance was used to monitor the regularities of EGCG adsorption in alternation with type A and B Gelatins and electrophoretic mobility measurements were used that indicated that the nature of assembly was dependent on Gelatin properties. It was shown that EGCG retains its antioxidant activity in the LbL assemblies. …

An Investigation Of The Use Of A High Resolution Adc As A Digital Biopotential Amplifier, Damon Berry, Frank Duignan, Richard Hayes

Conference Papers

Sigma delta analogue to digital converters have been used in many signal processing applications including some commercially available systems for sampling of bio-signals Bio-potential amplifiers have traditionally utilised specialised highquality analogue components to amplify bio-signals.

The central aim of this work is to investigate the benefits of using high-resolution sigma delta conversion as a digital amplification stage in the signal path of a bio-potential amplifier. A number of system arrangements specific to bio-potential measurement are presented and discussed. These arrangements are designed to use the high resolution capacity of the sigma delta converter in different ways, providing different benefits. To …

Influence Of Towing Force Magnitude On The Kinematics Of Supramaximal Sprinting, David A. Clark, Seth Kuhlman, Michelle B. Sabick, Ronald P. Pfeiffer, Nicole A. Knigge

Mechanical and Biomedical Engineering Faculty Publications and Presentations

The purpose of this study was to determine the influence of towing force magnitude on the kinematics of supramaximal sprinting. Ten high school and collegiate aged track and field athletes ran 60m maximal sprints under 5 different conditions: non-towed (NT), Tow A (2.0% body weight), Tow B (2.8%BW), Tow C (3.8%BW), and Tow D (4.7%BW). Three-dimensional kinematics of a 4-segment model of the right side of the body were collected starting at the 35m point of the trial. Significant differences were observed in stride length (SL) and horizontal velocity of the center of mass (VH) during Tow C and Tow …

Comparison Of An Experimental Bone Cement With A Commercial Control, Hydroset™, O. M. Clarkin, D. Boyd, S. Madigan, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

Glass polyalkenoate cements based on strontium calcium zinc silicate glasses (Zn-GPCs) and high molecular weight polyacrylic acids (PAA) (MW; 52,000-210,000) have been shown to exhibit mechanical properties and in vitro bioactivity suitable for arthroplasty applications. Unfortunately, these formulations exhibit working times and setting times which are too short for invasive surgical applications such as bone void filling and fracture fixation. In this study, Zn-GPCs were formulated using a low molecular weight PAA (MW; 12,700) and a modifying agent, trisodium citrate dihydrate (TSC), with the aim of improving the rheological properties of Zn-GPCs. These novel formulations were then compared with commercial …

Brain Tumor Progression Assessment Using Multiple Mri Volumes, Yufei Shen

Electrical & Computer Engineering Theses & Dissertations

Predicting and assessing tumor progression is important in brain tumor treatment. We attempt to use machine learning techniques to achieve consistency in assessing brain tumor progression. This thesis presents a prediction method of brain tumor progression by exploring a large MR database, which contains two patients ' complete records covering all their visits in the past two years. All ten MRI series, namely, apparent diffusion coefficient (ADC) , diffusion tensor imaging (DTI) , fractional anisotropy (FA), fluid attenuated inversion recovery (FLAIR), max eigenvalue (MAX), mid eigenvalue (MID), min eigenvalue (MIN) , post-contrast T₁-weighted, T₁- weighted, and …

Adjacent Slice Prostate Cancer Prediction To Inform Maldi Imaging Biomarker Analysis, Shao-Hui Chuang

Electrical & Computer Engineering Theses & Dissertations

Prostate cancer is the second most common type of cancer among men in the U.S. [1]. Traditionally, prostate cancer diagnosis is made by the analysis of prostate-specific antigen (PSA) levels and histopathological images of biopsy samples under microscopes. Proteomic biomarkers can improve upon these methods. MALDI molecular spectra imaging is used to visualize protein/peptide concentrations across biopsy samples to search for biomarker candidates. Unfortunately, traditional processing methods require histopathological examination on one slice of a biopsy sample while the adjacent slice is subjected to the tissue destroying desorption and ionization processes of MALDI. The highest confidence tumor regions gained from …

Optimal "Image-Based" Weighting For Energy-Resolved Ct, Taly Gilat Schmidt

Biomedical Engineering Faculty Research and Publications

This paper investigates a method of reconstructing images from energy-resolved CT data with negligible beam-hardening artifacts and improved contrast-to-nosie [sic] ratio (CNR) compared to conventional energy-weighting methods. Conceptually, the investigated method first reconstructs separate images from each energy bin. The final image is a linear combination of the energy-bin images, with the weights chosen to maximize the CNR in the final image. The optimal weight of a particular energy-bin image is derived to be proportional to the contrast-to-noise-variance ratio in that image. The investigated weighting method is referred to as “image-based” weighting, although, as will be described, the weights can …

Elastic, Viscous, And Mass Load Effects On Poststroke Muscle Recruitment And Co-Contraction During Reaching: A Pilot Study, Tina M. Stoeckmann, Katherine J. Sullivan, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

Background: Resistive exercise after stroke can improve strength (force-generating capacity) without increasing spasticity (velocity-dependent hypertonicity). However, the effect of resistive load type on muscle activation and co-contraction after stroke is not clear.

Objective: The purpose of this study was to determine the effect of load type (elastic, viscous, or mass) on muscle activation and co-contraction during resisted forward reaching in the paretic and nonparetic arms after stroke.

Design: This investigation was a single-session, mixed repeated-measures pilot study.

Methods: Twenty participants (10 with hemiplegia and 10 without neurologic involvement) reached forward with each arm against equivalent elastic, viscous, and mass loads. …

Prostate Cancer Biomarker Identification: A Comparative Study, Wenjuan Jiang

Computational Modeling & Simulation Engineering Theses & Dissertations

With the current development of proteomics techniques, the discovery of potential molecular biomarkers for early detection of prostate cancer has been greatly improved. In this thesis, we implemented five classifiers including the support vector machine (SVM), Bayesian Classifier, Decision Tree, Random Forest and the Multilayer perceptron (MLP) to test their effectiveness in prostate cancer biomarker identification using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) tissue imaging data. The classifiers were utilized to discriminate cancer mass spectra from normal ones for the data collected at the Eastern Virginia Medical School (EVMS). There are 94 7 spectra from normal tissues and 27 from …

Tissue Engineering Cellularized Silk-Based Ligament Analogues, Scott Sell

Theses and Dissertations

The resurgence, and eventual rise to prominence in the field of tissue engineering, that electrospinning has experienced over the last decade speaks to the simplicity and adaptability of the process. Electrospinning has been used for the fabrication of tissue engineering scaffolds intended for use in nearly every part of the human body: blood vessel, cartilage, bone, skin, nerve, connective tissue, etc. Diverse as the aforementioned tissues are in both form and function, electrospinning has found a niche in the repair of each due to its capacity to consistently create non-woven structures of fibers ranging from nano-to-micron size in diameter. These …

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

Biomedical 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.

Analysis Of Strain Transfer To Fbg’S For Sensorized Telerobotic End-Effector Applications, Dean Callaghan, Mark Mcgrath, Ginu Rajan, Eugene Coyle, Yuliya Semenova, Gerald Farrell

Books/Book chapters

Sensorized instruments which cater for the measurement of interaction forces during surgical procedures are not available on current commercial Minimally Invasive Robotic Surgical (MIRS) systems. This paper investigates the ef-fectiveness of advanced optical sensing technology (Fiber Bragg Grating) as sur-gical end effector strain/force sensors. The effects of adhesive bonding layer thickness and length are specifically addressed owing to their importance for ef-fective strain transfer and ensuring compactness of the resulting sensing arrange-ment. The strain transfer characteristics of the compound sensing arrangement are evaluated by the examination of shear transfer through the fiber coating and adhe-sive layers. Detailed analysis of the …

The Effect Of Particle Surface Area To Volume Ratio On Ion Release From Cocr Spheres, Darin J. Grandfield

Master's Theses

In 2005, over 200,000 Americans underwent a hip arthroplasty, the replacement of a hip joint with an artificial prosthesis. Of these arthroplasties, metal-on-metal type implants represent an increasing usage percentage. Metal-on-metal implants are selected largely for their low volumetric wear rate, durability, and resistance to corrosion. In spite of these advantages, little is known concerning the long-term consequences of heavy metal alloy use in the body, although early research indicates potentially carcinogenic results. This thesis is a preliminary investigation into these long term effects and their root causes.

An improved comprehension of the corrosion kinetics and the rate of ion …

Evaluating The Electrical Response Of Polyaniline To Mechanical Strain, Matthew L. Goebel

Master's Theses

This thesis focuses on the electrical output of polyaniline films subjected to uniaxial strain in hydrochloric acid solutions. Polyaniline belongs to novel class of materials known as conducting polymers. Alternating single and double bonds in the backbone of conducting polymers allow them to transmit electric charge when they are doped with negatively charged ions. Modifying the degree of doping and other electrical/chemical treatments allow conducting polymers to exhibit conducting, semi-conducting, or insulating electrical properties. Resilient mechanical properties, good processability, and low cost make conducting polymers good candidates for applications traditionally held by metals and semi-conductors.

When tensile strain is applied …

Preparation For Nerve Membrane Potential Readings Of A Leech, Laboratory Setup And Dissection Process, Jason Patrick Caulfield

Master's Theses

A well documented laboratory setup, leech preparation process, and bio-potential data recording process are needed. Repeatability and quality data recordings are essential and thus dictate the requirements of the laboratory setup and processes listed above. Advances in technology have both helped and hindered this development. While very precise equipment is required to record the low voltage bio-potentials, noisy electronic equipment and wires surrounding the work area provide high levels of interference. Proper laboratory setup and data recording processes, however, limit the unwanted interference. Quality data can only be recorded from a properly handled and prepared leech subject. Proper setup and …

Do Canines Experience The Effects Of Heart Rate Turbulence?, Melanie Ann Gurunathan

Master's Theses

Background

The canine cardiac system has been the model against which many Class III cardiac devices are validated. Thus, it is expected that the canine heart has very similar electrical model to that found in humans. In 1999, the absence of Heart Rate Turbulence (HRT) after a single Pre-Ventricular Contraction (PVC) was linked to high-risk patient after acute myocardial infarction. Studies of HRT were performed on high-risk patients with Holter-Monitors as were most subsequent HRT studies. If HRT could potentially be used as a risk factor of heart disease, it is interesting to study whether HRT is present following a …

Time-Frequency Analysis Of Intracardiac Electrogram, Erik Brockman

Master's Theses

The Cardiac Rhythm Management Division of St. Jude Medical specializes in the development of implantable cardioverter defibrillators that improve the quality of life for patients diagnosed with a variety of cardiac arrhythmias, especially for patients prone to sudden cardiac death. With the goal to improve detection of cardiac arrhythmias, this study explored the value in time-frequency analysis of intracardiac electrogram in four steps. The first two steps characterized, in the frequency domain, the waveforms that construct the cardiac cycle. The third step developed a new algorithm that putatively provides the least computationally expensive way to identifying cardiac waveforms in the …

Mechanical Simulation Of Articular Cartilage Based On Experimental Results, Kevin Matthew Stewart

Master's Theses

Recently, a constituent based cartilage growth finite element model (CGFEM) was developed in order to predict articular cartilage (AC) biomechanical properties before and after growth. Previous research has noted limitations in the CGFEM such as model convergence with growth periods greater than 12 days. The main aims of this work were to address these limitations through (1) implementation of an exact material Jacobian matrix definition using the Jaumann-Kirchhoff (J-K) method and (2) quantification of elastic material parameters based upon research findings of the Cal Poly Cartilage Biomechanics Group (CPGBG). The J-K method was successfully implemented into the CGFEM and exceeded …

Actual And Reference Evaporative Losses And Surface Coefficients Of A Maize Field During Nongrowing (Dormant) Periods, Christopher H. Hay, Suat Irmak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Effective water resources planning, allocation, management, and use in agroecosystems require accurate quantification of actual evapotranspiration (ET_c) during growing and nongrowing (dormant) periods. Prediction of ET_c for a variety of vegetation surfaces during the growing season has been researched extensively, but relatively little information exists on evaporative losses during nongrowing periods for different surfaces. The objectives of this research were to evaluate ET_c in relation to available energy, precipitation, and grass and alfalfa-reference ET (ET_o and ET_r) for a maize (Zea mays L.) field and to analyze the dynamics of surface coefficients …

The Impact Of Lipid Percentage On Fibrous Cap Stability In Atherosclerotic Lesions, Anita Lorraine Crompton

Master's Theses

Coronary artery disease (CAD) is a common cause of sudden cardiac death. Much of the disease is not completely understood, which makes treatment and prevention difficult. Many researchers are using technology, such as advanced imaging techniques and finite element analysis, to better understand the disease. While there is much progress being made to look at the analysis of actual excised diseased arteries, there is still not a standardized model to predict the future of any one lesion. The purpose of this study is to explore the possibility of creating a standardized model to predict the mechanical stability of the fibrous …

Preparation And Characterization Of Electrospun Poly(D, L-Lactide-Co-Glycolide) Scaffolds For Vascular Tissue Engineering And The Advancement Of An In Vitro Blood Vessel Mimic, Tiffany Richelle Pena

Master's Theses

PREPARATION AND CHARACTERIZATION OF ELECTROSPUN POLY(D,L-LACTIDE-CO-GLYCOLIDE) SCAFFFOLDS FOR VASCULAR TISSUE ENGINEERING AND THE ADVANCEMENT OF AN IN VITRO BLOOD VESSEL MIMIC

Tiffany Richelle Peña

Currently, an estimated 1 in every 3 adult Americans are affected by one or more cardiovascular complications. The most common complication is coronary artery disease, specifically atherosclerosis. Outcomes of balloon angioplasty treatments have been significantly improved with the addition of drug eluting stents to the process. Although both bare metal and drug eluting stents have greatly increased the effectiveness of angioplasty and decreased the occurrence of restenosis, several complications still exist. For this reason, the stent …

Design, Fabrication, And Implementation Of A Single-Cell Capture Chamber For A Microfluidic Impedance Sensor, Joshua-Jed Doria Fadriquela

Master's Theses

A microfluidic device was created for single-cell capture and analysis using polydimethylsiloxane (PDMS) channels and a glass substrate to develop a microfluidic single-cell impedance sensor for cell diagnostics. The device was fabricated using photolithography to create a master mold which in turn will use soft lithography to create the PDMS components for constant device production. The commercial software, COMSOLTM Multiphysics, was used to quantify the fluid dynamics in shallow micro-channels.

The device will be able to capture a cell and sequester it long enough to enable measurement of the impedance spectra that can characterize cell. The proposed device will be …