Biomedical Engineering and Bioengineering Commons^™

Mineralization Potential Of Electrospun Pdo-Nha-Fibrinogen Scaffolds Intended For Cleft Palate Repair, Isaac Rodriguez

Theses and Dissertations

The overall goal of this study was to identify mineralized scaffolds which can serve as potential alternatives to bone graft substitutes intended for cleft palate repair. The aim of this preliminary study was to evaluate the role of fibrinogen (Fg) and nano-hydroxyapatite (nHA) in enhancing mineralization potential of polydioxanone (PDO) electrospun scaffolds. Scaffolds were fabricated by blending PDO:nHA:Fg in the following weight ratios: 100:0:0, 50:25:25, 50:50:0, 50:0:50, 0:0:100 and 0:50:50. Scaffolds were immersed in different simulated body fluids for 5 and 14 days to induce mineralization. The inclusion of fibrinogen induced sheet-like mineralization while individual fiber mineralization was noticed in …

Electrophysiological Analysis In An Animal Model Of Dystonia, Kunal Chaniary

Theses and Dissertations

Dystonia is a movement disorder characterized by patterned, repetitive, and sustained muscle contractions that cause ineffective and often painful movements. The overall goal of this project was to understand the physiological mechanisms of dystonia in a rodent model as a basis for developing innovative treatments for secondary dystonias. The first half of the project was focused at developing essential techniques for systematically investigating the movement disorder in these animals. For achieving this, an innovative, multi-faceted approach was pursued starting with electromyographic (EMG) analysis for animal model validation, gait analysis for dystonia quantification, and development of a novel stereotaxic apparatus for …

Synthesis Of An Endothelial Cell Mimicking Surface Containing Thrombomodulin And Endothelial Protein C Receptor, Karl E. Kador

Department of Chemical and Biomolecular Engineering: Dissertations, Theses, and Student Research

Synthetic materials for use in blood contacting applications have been studied for many years with limited success. One of the main areas of need for these materials is the design of synthetic vascular grafts for use in the hundreds of thousands of patients who have coronary artery bypass grafting, many without suitable veins for autologous grafts. The design of these grafts is constrained by two common modes of failure, the formation of intimal hyperplasia (IH) and thrombosis. IH formation has been previously linked to a mismatching of the mechanical properties of the graft and has been overcome by creating grafts …

Effect Of Loading Condition On Traction Coefficient Between Shoes And Artificial Turf Surfaces, Seth M. Kuhlman, Michelle B. Sabick, Ronald Pfeiffer, Benjamin Cooper, Jackie Forhan

Mechanical and Biomedical Engineering Faculty Publications and Presentations

Background. The interaction between a shoe and a turf surface is highly complex and difficult to characterize. Over the three decades since artificial turf was introduced, researchers have attempted to understand the traction caused by the interaction. However, some of the methodologies used for traction measurements have not capitalized on advances in currently available technology for testing and most testing conditions have not simulated realistic physiological loads.

Method of Approach. To assess the effect of test condition on traction results, the newly designed TurfBuster testing device was used to collect traction data on FieldTurf™ brand artificial turf under varying conditions. …

Dna Microarray Image Segmentation Using Active Contours Without Edges Method, Shenghua Ni

Doctoral Dissertations

The goal of this dissertation is to build a better segmentation method for DNA microarray image processing. Segmentation is a partitioning process used to separate a spot area from a non-spot area in DNA microarrays. It directly affects the accuracy of gene expression analysis in the data mining process that follows. A number of DNA microarray segmentation methods have been proposed in the area, but even modern segmentation methods seem to have accuracy problems. In this dissertation, I will present a segmentation method based on the Active Contours Without Edges (ACWE) algorithm and apply it to two types of DNA …

Section Abstracts: Biomedical And General Engineering

Virginia Journal of Science

Abstracts of the Biomedical and General Engineering Section for the 88th Annual Meeting of the Virginia Academy of Science, May 20-21, 2010, James Madison University, Harrisonburg, VA.

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

Biomedical 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 in …

Modeling The Long Term Effects Of Alendronate On Bone Mass Preservation Of The Femur With Articular Surface And Total Hip Replacements, Trevor J. Hryce

Master's Theses

Calculating femoral bone density changes after hip arthroplasty is of interest to researchers and clinicians for predicting the longevity of the prosthetic implant and the surrounding bone. Recently clinicians have been administering bisphosphonate drugs in an attempt to reduce the bone resorption due to stress shielding caused by these implants. Current strain-adaptive computational models with bisphosphonate treatment don’t predict the long term effects or look at treatment with hip resurfacing implants. The main goal of this study was to create and validate a computer model of the human femur incorporating a bone remodeling algorithm based on biological remodeling processes and …

Tracking Of Bone Mass And Density During Childhood And Adolescence, Heidi J. Kalkwarf, Vicente Gilsanz, Joan M. Lappe, Sharon Oberfield, John A. Shepherd, Thomas N. Hangartner, Xangke Huang, Margaret M. Frederick, Karen K. Winer, Babette S. Zemel

Biomedical, Industrial & Human Factors Engineering Faculty Publications

Context: Whether a child with low bone mineral density (BMD) at one point in time will continue to have low BMD, despite continued growth and maturation, is important clinically. The stability of a characteristic during growth is referred to as “tracking.”

Objective: We examined the degree of tracking in bone mineral content (BMC) and BMD during childhood and adolescence and investigated whether tracking varied according to age, sexual maturation, and changes in growth status.

Design: We conducted a longitudinal study with measurements at baseline and annually for 3 yr.

Setting: The Bone Mineral Density in Childhood Study was conducted at …

Bi-Planar Postural Stability Model: Fitting Parameters To Patient Data Automatically, Andrew Michael Sovol

Master's Theses (2009 -)

Studies of children with cerebral palsy (CP) have shown that maintaining control of posture in quiet standing is often difficult. Physical therapy and assistive devices, both with or without surgery, may be employed in an effort to improve postural stability. Assessing the effectiveness of such interventions is important for healthcare providers and their patients. A previously created bi-planar model of posture control has been further developed as a method of assessment. This MATLAB and Simulink model has successfully replicated experimental results for typical adults and children, as well as children with CP across three different test conditions: eyes open, eyes …

Upper Extremity Kinetics During Lofstrand Crutch-Assisted Gait In Children, Neha Bhagchandani

Master's Theses (2009 -)

Complete biomechanical analysis helps evaluate the motion during various gait patterns for the upper and lower extremities. Extensive studies have been performed to evaluate unassisted gait patterns, but very little has been accomplished for studying assisted motion. Children with pathologies such as osteogenesis imperfecta, spinal cord injury, and cerebral palsy use assistive devices such as anterior and posterior walkers, canes, Lofstrand and axillary crutches for ambulation purposes.

Statistics show that there are currently about 566,000 crutch users in the United States. The long-term crutch users in this population can suffer various upper limb pathologies associated with extensive upper extremity (UE) …

A Non-Rigid Registration Method For Analyzing Myocardial Wall Motion For Cardiac Ct Images, Elizabeth B. Philps

Master's Theses (2009 -)

Cardiac resynchronization therapy (CRT) has a high percentage of non-responders. Successfully locating the optimal location for CRT lead placement on a priori images can increase efficiency in procedural preparation and execution and could potentially increase the rate of CRT responders.

Registration has been used in the past to assess the motion of medical images. Specifically, one method of non-rigid registration has been utilized to assess the motion of left ventricular MR cardiac images. As CT imaging is often performed as part of resynchronization treatment planning and is a fast and accessible means of imaging, extending this registration method to assessing …

Sensitivity Of Motor Adaptation To The Statistical Properties Of An Environmental Load, Timothy Michael Haswell

Master's Theses (2009 -)

Linear, limited-memory models capture many important features of adaptive motor performance during reaching, stepping and pointing. A recent study in our lab found that a model fitted to data obtained from subjects reaching against elastic loads which varied from trial-to-trial later failed to fit the steady-state response behavior of subjects exposed to deterministic, step changes in load. Does motor adaptation depend on statistical properties of the environment (eg. mean load strength and variability)? Neurologically intact volunteers (n=14) made 6 blocks of 100 planar, ballistic, 10cm, out-and-back reaching movements against spring-like loads having equilibrium positions at the hand's starting point. View …

Human Osteoblast Proliferation In Culture Following A Nanosecond Pulsed Electric Field (Nspef), Leonard Joseph Carinci Jr.

Biological Sciences Theses & Dissertations

Osteoblasts are mononucleate bone forming cells responsible for the deposition of new bone. Application of mechanical stress on bone reveals its ability to produce and release electric potentials across the cell membrane called piezoelectricity. The electric potentials produced in response to mechanical stress may have a direct correlation on osseous cells and the signaling pathways that regulate proliferation. Nanosecond pulsed electric fields (nsPEFs) are high intensity, ultrashort pulses which have the ability to maintain the integrity of the cell membrane by avoiding traditional electroporation. We delivered 8 nsPEFs (0.5 Hz) of a 25 kV/cm or 35 kV/cm electric field strength …

Combining Molecular And Imaging Biomarkers To Enhance Maldi Biomarker Analysis, Ayyappa Chowdary Vadlamudi

Electrical & Computer Engineering Theses & Dissertations

This thesis presents a three-step method to predict prostate cancer (PCa) regions on biopsy tissue samples based on high confident, low resolution PCa regions marked by a pathologist. First, a prediction model is designed to predict PCa regions using matrix-assisted laser desorption mass spectrometry (MALDI-MS) tissue imaging data from one prostate tissue slice. Second, a texture analysis technique is applied to a high magnification optical image for the same purpose from an adjacent tissue slice. Finally, those two results are fused to obtain the PCa regions that will assist MALDI imaging biomarker analysis. Experiments show that the texture analysis based …

Finite Element Analysis And Modeling Of A .38 Lead Round Nose Ballistic Gelatin Test, Danielle Datoc

Master's Theses

Firearms are present in two-thirds of United States households. As of 2003, roughly 500,000 projectile wounds occur annually in the United States. This costs an estimated 2.3 billion dollars of medical spending. The best treatment of gunshot wounds relies heavily on experience, but even with experience the unpredictable nature of ballistics can make treatment difficult.

Wound ballistics studies the injury pattern of a particular bullet. Ballistic gelatin tests are used to analyze this pattern. A block of 10 or 20% ballistic gelatin is set and a bullet is fired through the block. Key characteristics of the wound profile seen in …

An Investigative Study Into The Relationship Of Bone Morphogenetic Protein Antagonist Expression And Osteocyte Density By Region And Quadrant, Scott C. Mosher

Master's Theses

The role of cytokines and cell behavior and viability with respect to bone remodeling and bone behavior is an exciting area of orthopedic research. The purpose of this study was to investigate the relationships between BMP antagonist expression and osteocyte density, lacunar densities and osteocyte viability in cortical bone. Samples of unloaded tibial bone obtained from six C57Bl/6 mice were immunohistochemically stained for gremlin and noggin expression and also underwent methyl green staining to determine osteocyte presence. Bone sections were divided into four quadrants (cranial, caudal, medial and lateral) and three regions (proximal, mid shaft and distal), followed by analysis …

Biomechanical Comparison Of Wire Circlage And Rigid Plate Fixation For Median Sternotomy Closure In Human Cadaver Specimens, Mark Steven Wong

Master's Theses

Background:

Over 700,000 patients per year undergo open-heart surgery. Healing complication rates can be up to 5% of patients who undergo this procedure, with a morbidity rate of 50% if mediastinitis supervenes. A secure and rigid fixation of surgically divided sternum is critical to avoid healing complications. The purpose of this study was to compare the yield load, construct stiffness, ultimate load, displacement at ultimate load, and post-yield behavior of three sternotomy closure methods (Peristernal wires or Sternalock titanium plates) when stressed in each of three directions: lateral distraction, rostro-caudal (longitudinal) shear distraction, and anterior-posterior (transverse) shear in a cadaveric …

Characterization Of An Implicitly Resistively-Loaded Monopole Antenna In Lossy Liquid Media, Colleen J. Fox, Paul M. Meaney, Fridon Shubitidze, Lincoln Potwin, Keith D. Paulsen

Dartmouth Scholarship

Abstract

Microwave tomographic imaging of the breast for cancer detection is a topic of considerable interest because of the potential to exploit the apparent high-dielectric property contrast between normal and malignant tissue. An important component in the realization of an imaging system is the antenna array to be used for signal transmission/detection. The monopole antenna has proven to be useful in our implementation because it can be easily and accurately modeled and can be positioned in close proximity to the imaging target with high-element density when configured in an imaging array. Its frequency response is broadened considerably when radiating in …

Mechanical Properties Of Hydroxyapatite-Zirconia Compacts Sintered By Two Different Sintering Methods, Declan J. Curran, Thomas J. Fleming, Mark R. Towler, Stuart Hampshire

Chemical and Biochemical Engineering Faculty Research & Creative Works

Microwave sintering is traditionally employed to reduce the sintering temperature required to densify powder compacts. The effect of microwave heating on hydroxyapatite (HA)-zirconia (ZrO₂) green bodies has been investigated in order to understand how microwave energy may affect the physical and mechanical properties of the resultant densified composites. Laboratory synthesised nano-sized HA and a commercial nano-sized ZrO₂ powder have been ball milled to create mixtures containing 0-5 wt% ZrO₂ loadings. Compacts were microwave sintered at either 700, 1000 or 1200°C with a 1 h hold time. Comparative firings were also performed in a resistive element furnace …