Biomedical Engineering and Bioengineering Commons^™

Characterization Of Bone Material Properties And Microstructure In Osteogenesis Imperfecta/Brittle Bone Disease, John Robert Jameson

Dissertations (1934 -)

Osteogenesis imperfecta (OI) is a genetic disorder primarily associated with mutations to type I collagen and resulting in mild to severe bone fragility. To date, there is very little data quantifying OI cortical bone mechanics. The purpose of this dissertation was to investigate bone microstructure, mineralization, and mechanical properties in adolescents with OI. Characterization studies were performed on small osteotomy specimens obtained from the extremities during routine corrective surgeries. Nanoindentation was used to examine the longitudinal elastic modulus and hardness at the material level for mild OI type I vs. severe OI type III. Both modulus and hardness were significantly …

Neuromodulation For Depression: Insights Gained From Neuroimaging And Computational Models, Yagna Pathak

Dissertations (1934 -)

Major depressive disorder (MDD) is a public health concern worldwide, affecting a sixth of the American population. Neuromodulation therapies have been employed to treat severe cases of treatment resistant depression. These procedures attempt to modulate activity in cortical regions that represent nodes in brain circuits believed to be involved in MDD. One challenge in neuromodulation trials has been the difficulty in quantifying outcome variability. We sought to understand the effects of neuromodulation therapies and their sources of variability while adding an objective perspective to assess clinical improvement in neuropsychiatric disorders such as depression. The goal of my dissertation was to …

A Subject-Specific Multiscale Model Of Transcranial Magnetic Stimulation, Brian Daniel Goodwin

Dissertations (1934 -)

Transcranial magnetic stimulation (TMS) is a neuromodulation technique used to treat a variety of neurological disorders. While many types of neuromodulation therapy are invasive, TMS is an attractive alternative because it is noninvasive and has a very strong safety record. However, clinical use of TMS has preceded a thorough scientific understanding: its mechanisms of action remain elusive, and the spatial extent of modulation is not well understood. We created a subject-specific, multiscale computational model to gain insights into the physiological response during motor cortex TMS. Specifically, we developed an approach that integrates three main components: 1) a high-resolution anatomical MR …

Development And Degradation Behavior Of Magnesium Scaffolds Coated With Polycaprolactone For Bone Tissue Engineering, Mostafa Yazdimamaghani, Mehdi Razavi, Daryoosh Vashaee, Lobat Tayebi

Chemical and Biochemical Engineering Faculty Research & Creative Works

Rapid degradation of magnesium (Mg) alloys is the major drawback preventing these materials from being applicable as tissue engineering scaffolds. In order to resolve this issue, in this paper, porous Mg scaffolds coated by polycaprolactone (PCL) were synthesized and their material properties and in vitro biodegradation were fully examined. The results indicated that PCL coating can significantly enhance the compressive strength and degradation resistance of Mg scaffolds. We showed that while the uncoated Mg scaffold degrades completely (100% weight loss) after 72 h, the degradation (weight loss) of the Mg scaffolds coated by 3% and 6% PCL is only 36% …

Kinematic Analysis Of The Glenohumeral Joint: A Comparison Of Post-Operative Rotator Cuff Repair Patients And Controls, Ryan Richard Inawat

Master's Theses (2009 -)

Rotator cuff (RC) repair is a standard surgical intervention used to alleviate pain and loss of function in the shoulder due to torn RC tendons, involving re-attachment of the tendon to the humerus. Quantitative evaluation of kinematics following RC repair is possible with video motion analysis techniques, yet is rarely performed. With the purpose of quantifying the effects of RC repair, a Vicon 524 (Oxford, UK) motion analysis system was used to investigate three-dimensional (3D) kinematics of the glenohumeral (GH) joint and thorax following supraspinatus repair. A validated, 18 marker, inverse dynamics model based on ISB standards was applied to …

Within-Socket Myoelectric Prediction Of Continuous Ankle Kinematics For Control Of A Powered Transtibial Prosthesis, Samuel Farmer, M. Barbara Silver-Thorn, Philip A. Voglewede, Scott A. Beardsley

Biomedical Engineering Faculty Research and Publications

Objective. Powered robotic prostheses create a need for natural-feeling user interfaces and robust control schemes. Here, we examined the ability of a nonlinear autoregressive model to continuously map the kinematics of a transtibial prosthesis and electromyographic (EMG) activity recorded within socket to the future estimates of the prosthetic ankle angle in three transtibial amputees. Approach. Model performance was examined across subjects during level treadmill ambulation as a function of the size of the EMG sampling window and the temporal 'prediction' interval between the EMG/kinematic input and the model's estimate of future ankle angle to characterize the trade-off between model error, …

Data Completion Methods For Improved Developmental Stage Annotation Of Drosophila Embryos In Images, Chitsanu Janyalikit

Electrical & Computer Engineering Theses & Dissertations

Drosophila melanogaster is a dominant model organism for studying the function of animal genes in initial stages of embryogenesis. Usually, images containing Drosophila gene expression patterns are captured at different developmental stages to study the interconnection of animal genes. To achieve most biologically meaningful results, gene expression images from a similar stage should be compared. Currently, biologists manually classify embryos in images into different stages, which is time intensive and infeasible for current massively produced gene expression images. Therefore, there is a need to develop an automatic system for the annotation.

Gene expression information in embryo images usually appears as …

Apparatus And Method For Remote Assessment And Therapy Management In Medical Devices Via Interface Systems, Jeffrey Hargrove, Robert M. Ford, Thomas B. Johnson

Mechanical Engineering Patents

A remote medical assessment and therapy management apparatus comprising a center user interface, a center computer coupleable with the center user interface. The center computer displays information via the center user interface for use in developing a therapeutic prescription and receives therapeutic control inputs from a user. A remote device includes a medical diagnostic instrument for acquiring biophysical data from a patient, a medical therapeutic instrument that provides a therapy to the patient, and a remote computer that receives diagnostic signals from the diagnostic instrument and transmits therapeutic control signals to the therapeutic instrument. A network interface is connected between …

Carboxymethylcellulose Hydrogels Support Central Nervous System-Derived Tumor-Cell Chemotactic Migration: Comparison With Conventional Extracellular Matrix Macromolecules, Tanya Singh, Chandrasekhar Kothapalli, Devika Varma, Steven B. Nicoll, Maribel Vazquez

Publications and Research

The local microenvironment plays an important role in maintaining the dynamics of the extracellular matrix and the cell-extracellular matrix relationship. The extracellular matrix is a complex network of macromolecules with distinct mechanical and biochemical characteristics. Disruptions in extracellular matrix homeostasis are associated with the onset of cancer. The extracellular matrix becomes highly disorganized, and the cell-matrix relationship changes, resulting in altered cell-signaling processes and metastasis. Medulloblastoma is one of the most common malignant pediatric brain tumors in the United States. In order to gain a better understanding of the interplay between cell-extracellular matrix interactions and cell-migratory responses in tumors, eight …

Breast Cancer Detection Using Interferometric Music: Experimental And Numerical Assessment, Giuseppe Ruvio, Raffaele Solimene, Antonio Cuccaro, Domenico Gaetano, Jacinta Browne, Max Ammann

Articles

Purpose: In microwave breast cancer detection, it is often beneficial to arrange sensors in close proximity to the breast. The resultant coupling generally changes the antenna response. As an a priori characterization of the radio frequency system becomes difficult, this can lead to severe degradation of the detection efficacy. The purpose of this paper is to demonstrate the advantages of adopting an interferometric multiple signal classification (I-MUSIC) approach due to its limited dependence from a priori information on the antenna. The performance of I-MUSIC detection was measured in terms of signal-to-clutter ratio (SCR), signal-to-mean ratio (SMR), and spatial displacement (SD) …

Cutaneous Electrode Positioning, Jeffrey Hargrove, Susan R. Briggs

Mechanical Engineering Patents

A device and method for positioning a cutaneous electrode for delivery of electrical stimulation to a subject's head. A harness is worn on a subject's head with a first band of the harness worn in a closed loop around the subject's head and around a desired contact location on the subject's head. A tensioning strap of the harness is worn across the desired contact location and connected at spaced-apart attachment locations of the strap to spaced-apart attachment locations of the harness such that an electrode disposed over the desired contact location on the subject's head is held in place by …

Measurements Of Dna Damage And Repair In Bacillus Anthracis Sterne Spores By Uv Radiation, Chelsea C. Marcum

Theses and Dissertations

Spores of Bacillus anthracis (Ba) sterne were irradiated with 267nm UV light using small light emitting diodes. The pRB373 plasmid with a red fluorescent protein was transformed into Ba sterne cells prior to irradiation. Following irradiation, germination media was added and the spores were incubated for various times, to allow for DNA repair. The pRB373 plasmid was isolated and analyzed using real-time PCR. Primers were designed across the RFP in the plasmid yielding two amplicons, 245bp and 547bp long. PCR amplification was not achieved for germinated samples. Spore samples isolated using bead beating methods were amplified. Results indicate a quicker …

A Collagen‐Glycosaminoglycan‐Fibrin Scaffold For Heart Valve Tissue Engineering Applications, Claire Brougham, Stefan Jockenhoevel, Thomas Flanagan, Fergal O'Brien

Conference Papers

The field of heart valve biology and tissue engineering a heart valve continue to expand. The presentatio ns at this meeting reflect the advances made in both areas due to the multi-disciplinary approach taken by many laboratories.

Monitoring Micelle Formation In Mixtures Of Linear And Foldon-Capped Polypeptides With Light Scattering Spectroscopy, Janna Mino, John P. Gavin, Michael G. Price, Kiril Streletzky, Nolan Holland

Undergraduate Research Posters 2014

Elastin-like polypeptide (ELP) polymers are ideal for producing environmentally responsive micellar systems because they exhibit a transition from being water-soluble at low temperatures to phase-separated at high temperatures. For application development of drug delivery vehicles and biosensing nanoparticles, it is important to prepare spherical micelles of controlled diameter and shape. Since at a given salt concentration, the headgroup area for each foldon should be constant, the size of the micelles is expected to be proportional to the volume of the linear ELP available per foldon headgroup. Therefore, adding linear ELPs to a system of ELP-foldon should result in changes of …

Comparison Of Electronic And Mechanical Handgrip Devices In Lowering Blood Pressure, Katie Webb, Brandon Musarra, Megan O’Keefe, Shana Strunk, Courtney Perkins, Kenneth E. Sparks, Emily Kullman, Eddie T.C. Lam

Undergraduate Research Posters 2014

Hypertension causes billions of deaths per year (Millar et al., 2013). The Zona PlusTM is an expensive tool designed to lower blood pressure (BP) using isometric exercise. This exercise may be achieved using a less expensive Handgrip Dynamometer. PURPOSE: The purpose of this research is to determine if the Zona or Handgrip Dynamometer is more efficient at lowering BP and most cost effective for patients. METHODS: Twenty subjects used the Zona and twenty subjects used the dynamometer three times per week for six weeks. BP was taken once per week prior to the treatment. A maximum voluntary contraction (MVC) was …

Anatomy-Based Transmission Factors For Technique Optimization In Portable Chest X-Ray, Chris L. Liptak, W. Paul Segars, Ashraf G. Morgan, Frank F. Dong, Xiang Li

Undergraduate Research Posters 2014

Currently, portable x-ray examinations do not employ automatic exposure control (AEC). To aid in the design of a size-specific technique chart, acrylic slabs of various thicknesses are often used to estimate x-ray transmission factors for patients of various body thicknesses. This approach, while simple, does not account for patient anatomy, tissue heterogeneity, and the attenuation properties of the human body. To better account for these factors, in this work, we determined x-ray transmission factors using computational patient models that are anatomically realistic. A Monte Carlo program was developed to model a portable x-ray system. Detailed modeling was done of the …

3d Cultures Of Human Liver Cell Lines Encapsulated In Puramatrix On A Microarray Chip Platform, Pratap Lama, Alexander D. Roth, Pranav Joshi, Akshata Datar, Moo-Yeal Lee

Undergraduate Research Posters 2014

A high-throughput cell printing technology has developed to simulate the liver tissue environment using a hydrogel-based chip platform that has potential to shift in vivo drug toxicity models towards in vitro tests. However, the hydrophobic nature of polystyrene chips is not promoting direct adhesion of hydrogels, which created a problem with spot attachment. The main goal of this research is to create a surface chemistry that helps to attach a peptide-based hydrogel, including PuraMatrix, to a polystyrenebased micropillar chip. Seven analogs of maleic anhydride co-polymers were used to coat the micropillar chip to create a functional surface. Then, six ionic …

Sub-Diffusive Scattering Parameter Maps Recovered Using Wide-Field High-Frequency Structured Light Imaging, Stephen C. Kanick, David M. Mcclatchy, Venkataramanan Krishnaswamy, Jonathan T. Elliott, Keith D. Paulsen, Brian W. Pogue

Dartmouth Scholarship

This study investigates the hypothesis that structured light reflectance imaging with high spatial frequency patterns (fx) can be used to quantitatively map the anisotropic scattering phase function distribution (P(θs)) in turbid media. Monte Carlo simulations were used in part to establish a semi-empirical model of demodulated reflectance (Rd) in terms of dimensionless scattering (μ′sf−1x) and γ, a metric of the first two moments of the P(θs) distribution. Experiments completed in tissue-simulating phantoms showed that simultaneous analysis of Rd spectra sampled at multiple f …

Computational Modeling Of Pathophysiologic Responses To Exercise In Fontan Patients, Ethan Kung, James C. Perry, Christopher Davis, Francesco Migliavacca, Giancarlo Pennati, Alessandro Giardini, Tain-Yen Hsia, Alison Marsden

Publications

Reduced exercise capacity is nearly universal among Fontan patients. Although many factors have emerged as possible contributors, the degree to which each impacts the overall hemodynamics is largely unknown. Computational modeling provides a means to test hypotheses of causes of exercise intolerance via precisely controlled virtual experiments and measurements. We quantified the physiological impacts of commonly encountered, clinically relevant dysfunctions introduced to the exercising Fontan system via a previously developed lumped-parameter model of Fontan exercise. Elevated pulmonary arterial pressure was observed in all cases of dysfunction, correlated with lowered cardiac output (CO), and often mediated by elevated atrial pressure. Pulmonary …

Implementation And Validation Of Aortic Remodeling In Hypertensive Rats, Shijia Zhao, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

A computational framework was implemented and validated to better understand the hypertensive artery remodeling in both geometric dimensions and material properties. Integrating the stress-modulated remodeling equations into commercial finite element codes allows a better control and visualization of local mechanical parameters. Both arterial thickening and stiffening effects were captured and visualized. An adaptive material remodeling strategy combined with the element birth and death techniques for the geometrical growth were implemented. The numerically predicted remodeling results in terms of the wall thickness, inner diameter, and the ratio of elastin to collagen content of the artery were compared with and fine-tuned by …