Engineering Commons^™

Parameter Estimation Of The Arterial System, James Charles Carter Ii

Mechanical & Aerospace Engineering Theses & Dissertations

There are a number of disorders that originate from or involve faulty operation of the cardiovascular system. Diseases such as atherosclerosis, diabetes and hypertension can have a debilitating effect on blood flow. This makes the tools for simulating the effects of such diseases on blood flow important. Measures, such as pulse wave velocity, that are generated by models of the cardiovascular system can be important indicators of cardiac health. Although physically measurable, obtaining some parameters comes with a high cost and discomfort to the patient. Models can provide an assessment of many important parameters. The purpose of this project was …

Fatigue Testing Of Three Peristernal Median Sternotomy Closure Techniques, Cameron Wangsgard, David J. Cohen, Lanny V. Griffin

Biomedical Engineering

Failure of a sternotomy closure because of closure system fatigue is a complication that may result in dehiscence and put the individual at risk for serious complications. The purpose of this study was to assess the fatigue performance of three peristernal median sternotomy closure techniques (figure-of-eight stainless-steel wires, figure-of-eight stainless-steel cables, or Pectofix Dynamic Sternal Fixation [DSF] stainless-steel plates) in order to quantify the potential risk of fatigue failure of these devices when subject to cyclic loads in physiologically relevant loading directions.

Metabolic Engineering Of A Thermophilic Bacterium To Produce Ethanol At High Yield, A. Joe Shaw, Kara K. Podkaminer, Sunil G. Desai, John S. Bardsley, Stephen R. Rogers, Philip G. Thorne, David A. Hogsett, Lee R. Lynd

Dartmouth Scholarship

We report engineering Thermoanaerobacterium saccharolyticum, a thermophilic anaerobic bacterium that ferments xylan and biomass-derived sugars, to produce ethanol at high yield. Knockout of genes involved in organic acid formation (acetate kinase, phosphate acetyltransferase, and L-lactate dehydrogenase) resulted in a strain able to produce ethanol as the only detectable organic product and substantial changes in electron flow relative to the wild type. Ethanol formation in the engineered strain (ALK2) utilizes pyruvate:ferredoxin oxidoreductase with electrons transferred from ferredoxin to NAD(P), a pathway different from that in previously described microbes with a homoethanol fermentation. The homoethanologenic phenotype was stable for >150 generations …

Enhanced Na+/H+ Exchange During Ischemia And Reperfusion Impairs Mitochondrial Bioenergetics And Myocardial Function, Mohammed Aldakkak, David F. Stowe, James S. Heisner, Marisha Spence, Amadou K.S. Camara

Biomedical Engineering Faculty Research and Publications

Inhibition of Na+/H+ exchange (NHE) during ischemia reduces cardiac injury due to reduced reverse mode Na+/Ca2+ exchange. We hypothesized that activating NHE-1 at buffer pH 8 during ischemia increases mitochondrial oxidation, Ca2+ overload, and reactive O2 species (ROS) levels and worsens functional recovery in isolated hearts and that NHE inhibition reverses these effects. Guinea pig hearts were perfused with buffer at pH 7.4 (control) or pH 8 +/- NHE inhibitor eniporide for 10 minutes before and for 10 minutes after 35- minute ischemia and then for 110 minutes with pH 7.4 buffer alone. Mitochondrial NADH and FAD, [Ca2+], and superoxide …

An Engineering Evaluation Of Ankle Prosthetics, Christopher Thian, Stephen Tiernan, Fiona Mcevoy, Robert Flavin

Conference Papers

There are a wide range of different types of ankle replacements on the market today each with a
different mechanical design. Unfortunately the results of ankle replacements are not as good as hip
and knee replacements; this is due to the complexity of the ankle joint. In the early days of ankle
replacements some of the prosthetics only lasted 4 months. Recent developments have improved the
longevity of the replacements although, there are still many complications and failures of the
replacements, these include; the prosthetic components migrating into the bone, the components
failing due to stresses induced by the forces …

Assessment Of The Effects Of Increasing Levels Of Physiological Realism In The Computational Fluid Dynamics Analyses Of Implanted Coronary Stents, Jonathan Murphy, Fergal Boyle

Conference Papers

Coronary stent implantation can improve blood flow in an artery that has been narrowed by the build up of arterial plaque. However, the implantation of the stent will change the geometry of the vessel wall. The haemodynamic effects of the stents presence and alteration of the vessel wall are unclear. The redistribution of flow induced vessel wall shear stress (WSS) and wall shear stress gradient (WSSG) may directly contribute to restenosis (re-blockage). Computational fluid dynamics (CFD) is used extensively to identify these parameters in stented vessels. However, simplifications to the model of the stented artery are common. In this paper, …

Low-Flow Perfusion Of Guinea Pig Isolated Hearts With 26°C Air-Saturated Lifor Solution For 20 Hours Preserves Function And Metabolism, David F. Stowe, Amadou K.S. Camara, James S. Heisner, Mohammed Aldakkak, David R. Harder

Biomedical Engineering Faculty Research and Publications

Background

Donor human hearts cannot be preserved for >5 hours between explantation and recipient implantation. A better approach is needed to preserve transplantable hearts for longer periods, ideally at ambient conditions for transport. We tested whether Lifor solution could satisfactorily preserve guinea pig isolated hearts perfused at low flow with no added oxygen at room temperature for 20 hours.

Methods

Hearts were isolated from 18 guinea pigs and perfused initially with oxygenated Krebs–Ringer (KR) solution at 37°C. Hearts were then perfused with recirculated Lifor or cardioplegia (CP) solution (K⁺ 15 mmol/liter) equilibrated with room air at 20% of control …

Cephalometric Analysis Using Magnetic Resonance Imaging, Wade A. Williams

Loma Linda University Electronic Theses, Dissertations & Projects

Purpose: The purpose of this study was to determine if T1-weighted 3D magnetic resonance images performed at 3.0 Tesla could be used to conduct routine orthodontic cephalometric analysis.

Methods: Three cranial imaging methods were compared using sixteen non-growing subjects (10 male and 6 female) who were not claustrophobic, did not have any metallic restorations on the distal of first molars, had no medical implants and the female subjects were not pregnant. Sagittal cranial images were produced by three methods: (1) a digital lateral cephalometric (LC) radiograph (Orthophos XG Plus, Sirona^TM, Bensheim, Germany), (2) a 12-inch FOV cone beam …

Biomechanical Testing Of Upright Range Of Motion Versus Overhead Supine Range Of Motion, Linda Uko

Theses

Rehabilitation of an elbow, following injury, is not a well-studied subject. Clinically, there is not a general consensus on which recovery method is optimal for healing an unstable elbow. When dealing with medial collateral ligament deficiency, many authors have proposed several forearm positions that will yield proper healing of the unstable elbow. Some researchers believe that active mobilization of the elbow with the arm in a vertical position is a safe protocol for rehabilitation with the forearm oriented in a supine pronated position. It was also mentioned that the compressive forces due to the active mobilization of the arm will …

Classification Of Hand Held Shapes And Locations In Continuous Signing, Swetha Karri

Theses

Sign language for the deaf and hearing impaired replaces speech with manually produced signs. Each sign has been categorized as being combinations of handshape, movement, orientation, location, and facial expressions. Of the five sign parameters, this thesis focuses on classification of two of the main parameters, the hand shapes and locations, in continuous signing.

Since the nature of hand shapes is transient and not static, neural networks was used as a classifier for hand shapes. And since locations in sign language are defined by linguistic variables rather than by hard core position values, fuzzy logic was used as a classifier …

Design And Fabrication Of A Microneedle For The Implantation Of Floating Microstimulators, Faysal Ahmed

Theses

Neural prosthetics are used to stimulate any remaining functional nervous tissue in order to restore function in visual, auditory, or other physiological components associated with the nervous system. Microelectrodes have been used in stimulating and detecting electrical activity in neurons. When stimulating or recording neural tissue activity using microelectrodes, there are usually many problems and difficulties in obtaining the correct functionality and results. There is great difficulty in placing these microelectrodes in a specific location in the central nervous system due to various problems with the methodology used. Many different techniques such as the traditional interconnected microelectrodes have been an …

Photoplethysmorgraph-Derived Respiration, Priyanka Pankaj Shah

Theses

Stress & Motivated Behavioral Institute (SMBI) has developed a research program to provide an objective evaluation of the physiological and neurocognitive impact of human electromuscular muscular interference (HEMI) devices in humans. The initial step is to understand their physiological impact, which is characterized by vital signs. Volunteers are recruited from HEMI training programs with the provision that data collection can not interfere with training. Thus, an ambulatory system was assembled. There are two main issues in the current ambulatory system, one of which is the reliability of the respiration signal obtained using a strain gauge respiration band, mainly due to …

A Novel Method For Characterization Of Peripheral Nerve Fiber Size Distributions By Group Delay Measurements And Simulated Annealing Optimization, Robert B. Szlavik, Galen E. Turner, Iii

Biomedical Engineering

The ability to determine the characteristics of peripheral nerve fiber size distributions would provide additional information to clinicians for the diagnosis of specific pathologies of the peripheral nervous system. Investigation of these conditions, using electro-diagnostic techniques, is advantageous in the sense that such techniques tend to be minimally invasive yet provide valuable diagnostic information. One of the principal electro-diagnostic tools available to the clinician is the nerve conduction velocity test. While the peripheral nerve conduction velocity test can provide useful information to the clinician regarding the viability of the nerve under study, it is a single parameter test that yields …

The Spaceflight Environment And The Skeletal System, Eric Bandstra

All Dissertations

The spaceflight environment presents many challenges to the human body. Bone loss in astronauts is a well known consequence of reduced loading in the weightless environment of low-earth orbit. Recent studies have also indicated that spaceflight relevant types of radiation (at relatively high doses) have deleterious effects on trabecular bone. Both of these represent potential skeletal challenges during long-duration spaceflight. The objective of these studies is to examine the response of bone to models of the spaceflight environment.
Astronauts will likely absorb doses of protons and heavy ions during lengthy missions outside the Earth's magnetosphere. Following exposure to a range …

Chitosan Derivatives For Tissue Engineering, Yongzhi Qiu

All Dissertations

Chitosan, a naturally occurring polysaccharide, and its derivatives have been widely explored for biomedical applications due to their biocompatibility and biodegradability. In our studies, we developed a series of chitosan derivatives through chemical modifications. These chitosan derivatives not only possess better processibility in scaffolds fabrication, but also show excellent potentials in tissue engineering applications, including blood vessel and bone tissue engineering.
The excellent antithrombogenic property is crucial for vascular engineering applications, especially in engineering small-diameter blood vessels. In our studies, chitosan was chemically modified by phthalization and the phthalized chitosan exhibited great antithrombogenic property. Through a wet- phase-inversion process, tubular …

Engineered Micro-Environments And Vibrational Culture Systems For Vocal Fold Tissue Engineering, Jaishankar Kutty

All Dissertations

Voice is produced by the conversion of aerodynamic energy from exhalation to acoustical energy for voice production by the vocal folds (membranous connective tissue) located in the larynx. The quality of voice depends on the biomechanical properties of the multi-layered vocal fold tissue which derive from its extracellular matrix (ECM) organization and composition. The wound healing response to vocal fold injuries is characterized by scarring and subsequent dysphonia due to alterations in the biomechanical properties of the tissue.
The work presented here is motivated by the importance of voice in maintaining quality of life and the inability of current treatment …

Cues For Cellular Assembly Of Vascular Elastin Networks, Chandrasekhar Kothapalli

All Dissertations

Elastin, a structural protein distributed in the extracellular matrix of vascular tissues is critical to the maintenance of vascular mechanics, besides regulation of cell-signaling pathways involved in injury response and morphogenesis. Thus, congenital absence or disease-mediated degradation of vascular elastin and its malformation within native vessels due to innately poor elastin synthesis by adult vascular cells compromise vascular homeostasis. Current elastin regenerative strategies using tissue engineering principles are limited by the progressive destabilization of tropoelastin mRNA expression in adult vascular cells and the unavailability of scaffolds that can provide cellular cues necessary to up-regulate elastin synthesis and regenerate faithful mimics …

Image-Guided Raman Spectroscopic Recovery Of Canine Cortical Bone Contrast In Situ, Subhadra Srinivasan, Matthew Schulmerich, Jacqueline H. Cole, Kathryn Dooley, Jaclynn M. Kreider, Brian W. Pogue

Dartmouth Scholarship

Raman scattering provides valuable biochemical and molecular markers for studying bone tissue composition with use in predicting fracture risk in osteoporosis. Raman tomography can image through a few centimeters of tissue but is limited by low spatial resolution. X-ray computed tomography (CT) imaging can provide high-resolution image-guidance of the Raman spectroscopic characterization, which enhances the quantitative recovery of the Raman signals, and this technique provides additional information to standard imaging methods. This hypothesis was tested in data measured from Teflon tissue phantoms and from a canine limb. Image-guided Raman spectroscopy (IG-RS) of the canine limb using CT images of the …

Department Of Biological Systems Engineering Newsletter, Vol. 4 No. 1, August 2008

BSE Department Magazine

Contents:
New Biomedical Lab Makes Debut
From the Department Head
The Dean's List
Meet the Faculty
Alumni News
Student News
UCARE
Graduates
John Miller: A Success Story
Discover Your Career Mechanized Systems Management
Alumnus Profile
Faculty and Staff News
Comings and Goings
Spreading the word about No-till

A Design Aid For Determining Width Of Filter Strips, Michael G. Dosskey, M. J. Helmers, Dean E. Eisenhauer

Biological Systems Engineering: Papers and Publications

Watershed planners need a tool for determining width of filter strips that is accurate enough for developing cost-effective site designs and easy enough to use for making quick determinations on a large number and variety of sites. This study employed the process-based Vegetative Filter Strip Model to evaluate the relationship between filter strip width and trap¬ping efficiency for sediment and water and to produce a design aid for use where specific water quality targets must be met. Model simulations illustrate that relatively narrow filter strips can have high impact in some situations, while in others even a modest impact cannot …

Analytical Study Of Blood Flow With Periodic Body Acceleration In The Presence Of Magnetic Field, Dr. Anil Kumar

Dr. Anil Kumar

In this paper we consider a human body is quite often subjected to the acceleration in the magnetic e#11;ects. The induced magnetic #12;eld is neglected. To account such acceleration can generate signi#12;cant e#11;ects on blood circulation depending on the con#12;guration and geometry of the blood arteries. The current study is related to mathematical model of study of blood ow in presence of magnetic e#11;ects subjected to externally imposed periodic body acceleration. By using the #12;nite Hankel Transforms, an exact solution of steady ow of blood as an incompressible, couple stress uid has been obtained. The results have been compared with …

Synthesis And Characterization Of Polyionic Hydrogels, Pooja Desai

Theses and Dissertations

In this study we describe novel polyionic dendrimer – PEG hydrogels for drug delivery. Hydrogels have a crosslinked insoluble network of polymer chains, which have found many applications including drug delivery and tissue regeneration. Dendrimers provide an ideal platform for drug delivery as they possess a well-defined highly branched nanoscale architecture with many reactive surface groups. Their highly clustered surface groups allow for targeted drug delivery and high drug payload to enhance therapeutic effectiveness. This study presented a new type of polyionic hydrogels based on dendrimers with potential applications in drug delivery and tissue engineering. Polyethylene glycol (PEG) with various …

Preparing, Characterizing, On-Line Digital Image Processing Of Residence Time Distribution And Modeling Of Mechanical Properties Of Nanocomposite Foams, Siew Yoong Lee

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

The objectives of this research were to prepare, characterize and to study the effects of organoclay and extrusion variables on the physical, mechanical, structural, thermal and functional properties of tapioca starch (TS)/poly(lactic acid) (PLA) nanocomposite foams. On-line digital imaging processing was used to determine residence time distribution (RTD). Adaptive neuro-fuzzy inference system (ANFIS) was used to model the mechanical properties of nanocomposite foams.

Four different organoclays (Cloisite 10A, 25A, 93A, 15A) were used to produce nanocomposite foams by melt-intercalation. The properties were characterized using Xray diffraction, scanning electron microscopy, differential scanning calorimetric, and Instron universal testing machine. The properties were …

Assessment Of Fifth Metatarsal Etiology, Daniel Reed

All Theses

The fifth metatarsal 'Jones Fracture' is a fracture that occurs 3.5cm distal to the tuberosity. It is an injury that is common in athletes, especially those who participate in sports with a lot of lateral movement. The Jones Fracture is known for its difficulty to heal due to non-union and re-fracture. There has been much research recently regarding in-shoe pressure distributions and their relation to shoe type, movement, and shoe surface interaction. However, only the forces along the bottom of the foot have been investigated. Literature and the direction of fracture seem to implicate a force on the lateral portion …

Risedronate Prevents Early Bone Loss Resulting From Whole-Body Irradiation, Eric Livingston

All Theses

Osteoporosis is a condition characterized by a reduction in bone strength resulting in an overall increase in the risk of fracture. There are many factors that contribute to the development of this condition, including ionizing radiation exposure. Declines in bone volume and trabecular micro-architecture have been found following exposure to multiple types of radiation. Past research has implicated reduction of osteoblast function and changes to vasculature as the primary sources of bone deterioration. Recently, an early increase in osteoclast number was observed following exposure to low-energy X-rays, identifying an increase in resorption as a possible cause and potential target for …

Biohazard Neutralization Based On Lipid Technology, Edelmira Bosques

FIU Electronic Theses and Dissertations

A rapid detection and neutralization method for biowarfare agents would be a great biodefense in war times. With this purpose, liposomes were developed following the lipid film formation, rehydration, and extrusion procedure as the production method. MgOCl2 was encapsulated in the liposomes and it was tested with three different bacterium B. cereus; B. thuringiensis; and B. subtilis. For specificity, the liposomes were modified with a polyclonal antibody against B. cereus and B. subtilis. The liposomes were characterized using a Malvern Zetasizer Instrument, and the study revealed stability of the liposomes stored at 4°C for a …

Biomechanical Evaluation Of Two Methods Of Humeral Shaft Fixation, Joshua Catanzarite

All Theses

Biomechanical evaluations of fracture fixation devices attempt to determine implant performance by approximating the in vivo conditions. This performance is affected by many factors and relies on the complex bone-implant interface. Biomechanical tests can be designed in a variety of ways in order to evaluate device performance with respect to any number of these bone-implant interactions. Standardized tests, designed by groups such as the American Society for Testing and Materials (ASTM), are often designed either to determine the performance of a specific type of fixation device or for direct comparison between different devices. Additionally, many biomechanical evaluations are designed for …

Quantifying Antalgic Gait Knee Function Using Inertial Sensor Technology, William Mostertz

All Theses

The use of body-fixed inertial sensors to analyze human movement may prove useful in the medical field. Improving orthopaedic device design, diagnosing musculoskeletal disorders, and rehabilitation assessment could all benefit from a mobile gait analysis system based on inertial sensors. More specifically, patients recovering from lower limb corrective surgeries tend to adjust gait patterns to accommodate pain, a condition referred to as antalgic gait. Currently there is no quantitative method available to assess recovery for this patient population during post-operative management. A comparison of the inertial sensor system with the camera-based industry standard has confirmed it as a viable method …

Effects Of Narrow Grass Hedges On Nutrient Transport From Land Application Areas, John E. Gilley, Bahman Eghball, David B. Marx

Department of Biological Systems Engineering: Conference Presentations and White Papers

The placement of stiff-stemmed grass hedges on the contour along a hill slope has been shown to decrease runoff nutrient transport. This study was conducted to measure the effectiveness of a narrow grass hedge in reducing runoff nutrient transport from plots with a range of soil nutrient values. Composted beef cattle manure was applied at dry weights of 0, 68, 105, 142, and 178 Mg ha^-1 to a silty clay loam soil and then incorporated by disking. Soil samples were collected 243 days later for analysis of water-soluble phosphorus (WSP), Bray and Kurtz No.1 phosphorus (Bray-1 P), NO_{3 …}

Force Measurement Methods In Telerobotic Surgery: Implications For End-Effector Manufacture, Dean Callaghan, Mark Mcgrath, Eugene Coyle

Articles

Haptic feedback in telesurgical applications refers to the relaying of position and force information from a remote surgical site to the surgeon in real-time during a surgical procedure. This feedback, coupled with visual information via microscopic cameras, has the potential to provide the surgeon with additional ‘feel’ for the manipulations being performed at the instrument-biological tissue interface. This increased sensitivity has many associated benefits which include, but are not limited to; minimal tissue damage, reduced recuperation periods, and less patient trauma. The inclusion of haptic feedback leads to reduction in surgeon fatigue which contributes to enhanced performance during operation. Commercially …