Biomedical Engineering and Bioengineering Commons^™

The Influence Of Heterogeneous Meninges On The Brain Mechanics Under Primary Blast Loading, Linxia Gu, Mehdi S. Chafi, Shailesh Ganpule, Namas Chandra

Department of Mechanical and Materials Engineering: Faculty Publications

In the modeling of brain mechanics subjected to primary blast waves, there is currently no consensus on how many biological components to be used in the brain–meninges–skull complex, and what type of constitutive models to be adopted. The objective of this study is to determine the role of layered meninges in damping the dynamic response of the brain under primary blast loadings. A composite structures composed of eight solid relevant layers (including the pia, cerebrospinal fluid (CSF), dura maters) with different mechanical properties are constructed to mimic the heterogeneous human head. A hyper-viscoelastic material model is developed to better represent …

Reducing The Radiation Dose To Women Receiving Cardiac Ct Scans, Michael Hoppe

Master's Theses (2009 -)

This thesis aims to quantify the reduction in radiation dose deposited in glandular breast tissue achieved by using tilted gantry acquisition during cardiac CT scans. Previous work by Halpern et al. suggested using tilted acquisition parallel to the long axis of the patient’s heart. However, for a larger portion of the population this is not feasible due to the design of current scanners (which are limited to maximum tilt angles of 30 degrees). This study investigated the potential dose reduction and image quality effects at commercially available tilt angles between 0-30 degrees through simulation and experimental studies.

Upon IRB approval, …

Developing Unique Engineering Solutions To Improve Patient Safety, Bradley Watts, Douglas Van Citters, Brian Shiner, Peter Mills

Dartmouth Scholarship

Many efforts to improve healthcare safety have focused on redesigning processes of care or retraining clinicians. Far less attention has been focused on the use of new technologies to improve safety. We present the results of a unique collaboration between the VA National Center for Patient Safety (NCPS) and the Thayer School of Engineering at Dartmouth College. Each year, the NCPS identifies safety problems across the VA that could be addressed with newly-engineered devices. Teams of Thayer students and faculty participating in a senior design course evaluate and engineer a solution for one of the problems. Exemplar projects have targeted …

Useful Field Of View Predicts Driving In The Presence Of Distracters, Joanne M. Wood, Alex Chaparro, Philippe Lacherez, Louise Hickson

Publications

Purpose. The Useful Field of View (UFOV®) test has been shown to be highly effective in predicting crash risk among older adults. An important question which we examined in this study is whether this association is due to the ability of the UFOV to predict difficulties in attention-demanding driving situations that involve either visual or auditory distracters.

Methods. Participants included 92 community-living adults (mean age 73.6 +- 5.4 years; range 65– 88 years) who completed all three subtests of the UFOV involving assessment of visual processing speed (subtest 1), divided attention (subtest 2), and selective attention (subtest 3); driving safety …

Synergistic Effect Of Subnanosecond Pulsed Electric Fields And Temperature On The Viability Of Biological Cells, James Thomas Camp

Electrical & Computer Engineering Theses & Dissertations

Pulsed electric fields have been used to induce a biological response in cells, and at sufficient energy, can cause cell death. By reducing the pulse duration from presently used nanosecond to subnanosecond ranges, the electric field can be delivered to biological tissue non-invasively by the use of an antenna instead of electrodes, such as needles. Studies have previously been completed in which the aim was to determine the energy density (electric field strength, number of pulses) required to induce cell death with 800 ps pulses. Based on this data, it was concluded that for pulse durations of 200 ps, with …

Quantifying The Impact Of Altered Hemodynamics And Vascular Biomechanics To Changes In Structure And Function In Native And Corrected Aortic Coarctation, Arjun Menon

Dissertations (1934 -)

Coarctation of the aorta (CoA) is associated with substantial cardiovascular morbidities despite successful treatment through surgical or catheter-based intervention. Although specific mechanisms leading to these morbidities remain elusive, abnormal hemodynamics and vascular biomechanics are implicated. We used a novel animal model that facilitates quantification of CoA-induced hemodynamic and vascular biomechanics alterations and their impact on vascular structure and function, independent of genetic or confounding factors. Rabbits underwent thoracic CoA at 10 weeks of age (~9 human years) to induce a 20 mmHg blood pressure (BP) gradient using permanent or dissolvable suture thereby replicating untreated and corrected CoA. Computational fluid dynamics …

The Impact Of Increased Collateral Flow On Transverse Arteriolar Microvascular Tree Morphology, David Danzeiser

Master's Theses

The goal of this study was to understand how arteriogenesis impacts transverse arteriolar tree structure. The previous process involved a vascular casting technique that utilized black India ink as the casting agent and manual measurement of vessel morphology with ImageJ. This study decreased the complexity of the casted samples by using a casting compound called Microfil. Microfil’s viscosity can be adjusted and through experimentation, a viscosity was found that stopped at the capillary level, allowing only the arterial side of the circulation to be casted. A macro in ImageJ was written to help with morphological measurement by bundling vessel length …

Advanced Visualization And Intuitive User Interface Systems For Biomedical Applications, David Quam

Master's Theses (2009 -)

Modern scientific research produces data at rates that far outpace our ability to comprehend and analyze it. Such sources include medical imaging data and computer simulations, where technological advancements and spatiotemporal resolution generate increasing amounts of data from each scan or simulation. A bottleneck has developed whereby medical professionals and researchers are unable to fully use the advanced information available to them. By integrating computer science, computer graphics, artistic ability and medical expertise, scientific visualization of medical data has become a new field of study. The objective of this thesis is to develop two visualization systems that use advanced visualization, …

Abnormal Neuromuscular Fatigue And Motor Performance Of The Knee Extensors Post Stroke, Henry Kuhnen

Master's Theses (2009 -)

Stroke causes paresis in leg muscles, such as the knee extensors, that significantly impairs motor control and function during tasks such as walking. Reduced endurance and increased kinematic asymmetries during walking over time indicate paretic musculature may fatigue more quickly than non-paretic musculature. The primary purpose of this study was to identify abnormalities in neuromuscular fatigue (reduction in force over time) of the paretic knee extensors and associate them with motor performance.

We investigated the effects of repeated six second isometric submaximal (30% of maximum voluntary contraction) knee extensor fatiguing contractions on task failure and motor performance in ten chronic …

Evaluation Of Decellularization Procedures For Porcine Arteries, Charles Clapp

Biomedical Engineering

Coronary artery disease has become the leading cause of death in the United States, with over 425,000 deaths in 2006. Stenting has evolved into the preferred preventative technique for myocardial infarction by opening up an occluded artery, due to its low invasiveness compared to the alternative of coronary artery bypass grafting. Bare metal stents have been improved by coating with anti-proliferative drugs to advance their effects, but even drug eluting stents still have a risk of restenosis, thrombus formation, and necessary revascularization. Continual advancement in stent design necessitates faster, effective pre-clinical evaluation techniques. Kristen Cardinal, Ph.D., developed the blood vessel …

Image-Guided Robotic Dental Implantation With Natural-Root-Formed Implants, Xiaoyan Sun

Electrical & Computer Engineering Theses & Dissertations

Dental implantation is now recognized as the standard of the care for tooth replacement. Although many studies show high short term survival rates greater than 95%, long term studies (> 5 years) have shown success rates as low as 41.9%. Reasons affecting the long term success rates might include surgical factors such as limited accuracy of implant placement, lack of spacing controls, and overheating during the placement.

In this dissertation, a comprehensive solution for improving the outcome of current dental implantation is presented, which includes computer-aided preoperative planning for better visualization of patient-specific information and automated robotic site-preparation for superior …

Nonosecond Pulsed Electric Field Induced Changes In Dielectric Properties Of Biological Cells, Jie Zhuang

Electrical & Computer Engineering Theses & Dissertations

Nanosecond pulsed electric field induced biological effects have been a focus of research interests since the new millennium. Promising biomedical applications, e.g. tumor treatment and wound healing, are emerging based on this principle. Although the exact mechanisms behind the nanosecond pulse-cell interactions are not completely understood yet, it is generally believed that charging along the cell membranes (including intracellular membranes) and formation of membrane pores trigger subsequent biological responses, and the number and quality of pores are responsible for the cell fate. The immediate charging response of a biological cell to a nanosecond pulsed electric field exposure relies on the …

Electrokinetic Transport Phenomena In Nanofluidic Devices, Mingkan Zhang

Mechanical & Aerospace Engineering Theses & Dissertations

Nanofluidic devices have wide potential applications in biology, chemistry and medicine, and have been proven to be very valuable in sensing biological particles (e.g., DNA and proteins) due to their efficiency, sensitivity and portability. Electrokinetic control of ion, fluid, and particle transport by using only electric field is the most popular method employed in nanofluidic devices. A comprehensive understanding of the electrokinetic ion, fluid, and particle transport in nanofluidics is essential for developing nanofluidic devices for the detection of single molecules, such as the next generation nanopore-based DNA sequencing technology. This research explored numerical simulation of electrokinetic ion and fluid …

Biomechanics And Plaque Progression In Human Coronary Arteries, Don P. Giddens, Habib Samady, Jin Suo, Parham Eshtehardi, Michael Mcdaniel, Saurabh S. Dhawan, Lucas Timmins, John Oshinski

Computational Fluid Dynamics (CFD) in Medicine And Biology in Conjunction With the Seventh International Biofluid Mechanics Symposium

No abstract provided.

Blood Flow Through The Aorta In A Mouse Model Of Atherosclerosis, J. Hough, P. Assemat, K.K.W. Siu, J.A. Armitage, K. Contreras, A. Aprico, A. Dart, J. Ching-Dusting, K. Hourigan

Computational Fluid Dynamics (CFD) in Medicine And Biology in Conjunction With the Seventh International Biofluid Mechanics Symposium

No abstract provided.

Image-Based Vs. Patient-Specific What Is The Difference, And Does It Matter?, David Steinman

Computational Fluid Dynamics (CFD) in Medicine And Biology in Conjunction With the Seventh International Biofluid Mechanics Symposium

No abstract provided.

Frequency And Distribution Of Microcalcifications In Vulnerable Plaque And Their Role In Fibrous Cap Rupture, Natalia Maldonado, Adreanne Kelly, Yuliya Vengrenyuk, Luis Cardoso, Sheldon Weinbaum

Computational Fluid Dynamics (CFD) in Medicine And Biology in Conjunction With the Seventh International Biofluid Mechanics Symposium

No abstract provided.

Evaluation Of Transfer Technologies To Preserve Shoulder Function In Sci, Karen Michelle Mann

USF Tampa Graduate Theses and Dissertations

This study investigated a series of independent unassisted and device-assisted transfers from a wheelchair to vehicle mock-up and vice versa while simultaneously capturing kinematic, kinetic and electromyographic (EMG) data of impaired volunteers. The study provides a venue for observation and evaluation of upper extremity (UE) joint stresses, muscular force and functional demands associated with transfers in persons with spinal cord injury (SCI) to ultimately prevent UE injury, minimize excessive stress, preserve functionality and limit pain. If people with SCI lose function of their UEs, due to pain and/or degeneration, they must then rely on others for everyday tasks.

Five paraplegic …

Chemical Modification Of Polysaccharides Using Reactive Extrusion, Pratik Bhandari

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

The objective of this dissertation was to study the use of reactive extrusion for the chemical modifications of starch and cellulose. A carboxymethyl derivative of starch and carboxymethyl and acetate derivatives of cellulose were prepared using reactive extrusion.

Carboxymethyl starch with rapid swelling properties in water was prepared using reactive extrusion. This was achieved by controlling the gelatinization and through the use of NaOH by controlling the water/ethanol ratio. The effects of NaOH, H₂O, temperature, ethanol, sodium mono chloro acetate, sodium tripolyphosphate, citric acid, epichlorohydrin and extruder screw configuration on the degree of substitution of carboxymethyl starch were …

Methods For Enhancing Expression Of Secondary Cell Wall Cellulose Synthases In Plants, Chandrashekhar P. Joshi

Michigan Tech Patents

Described are methods for making transgenic plants capable of expressing secondary cell wall cellulose synthases and methods of enhancing expression of secondary cell wall cellulose synthases in plants. Also described are plants produced by the methods. Plants comprising at least three exogenous polynucleotides encoding secondary cell wall cellulose synthases are also provided.