Biomedical Engineering and Bioengineering Commons^™

An Experimental Study Of The Implementation Of A Fluid Diode Inside A Sano Shunt, Patrick Austin Lane

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Fluid diodes are fluidic devices that enhance fluid flow in a particular direction while inhibiting it in the opposite direction without the use of moving parts. This is accomplished through the use of nozzle shaped geometry on one side of the diode, and cusp shaped geometry on the opposing side. Fluid meets very little resistance as is travels though the nozzle side of the diode. The cusps on the other side of the diode reduce the effective flow area, thereby inhibiting flow. The objective of this study is to determine the effectiveness of a fluid diode installed in a reconstructed …

Image Reconstruction In Photoacoustic Computed Tomography With Acoustically Heterogeneous Media, Chao Huang

All Theses and Dissertations (ETDs)

Photoacoustic computed tomography (PACT), also known as optoacoustic or thermoacoustic tomography, is a rapidly emerging hybrid imaging modality that combines optical image contrast with ultrasound detection. The majority of currently available PACT image reconstruction algorithms are based on idealized imaging models that assume a lossless and acoustically homogeneous medium. However, in many applications of PACT these assumptions are violated and the induced photoacoustic (PA) wavefields are scattered and absorbed as they propagate to the receiving transducers. In those applications of PACT, the reconstructed images can contain significant distortions and artifacts if the inhomogeneous acoustic properties of the object are not …

How Sensitive Is The Deltoid Moment Arm To Joint Center Changes With Rtsa?, David Walker, Allison Kinney, Aimee Struk, Benjamin J. Fregly, Thomas Wright, Scott Banks

Mechanical and Aerospace Engineering Faculty Publications

The goal of this study was to assess the sensitivity of the deltoid muscle moment arms as a function of joint configuration for an existing RTSA subject. High variations were found for all three deltoid components. Variation over the entire abduction arc was greatest in the anterior and lateral deltoid, while the posterior deltoid moment arm was mostly sensitive to joint center changes early in the abduction arc. Moment arm changes of 10-16mm represent a significant amount of the total deltoid moment arm. This means there is an opportunity to dramatically change the deltoid moments arms through surgical placement of …

Deltoid Moment Arms During Abduction: A Subject-Specific Musculoskeletal Modeling Study In Healthy Shoulders And Shoulders With Rtsa, David Walker, Allison Kinney, Aimee Struk, Benjamin J. Fregly, Thomas Wright, Scott Banks

Mechanical and Aerospace Engineering Faculty Publications

Reverse total shoulder arthroplasty (RTSA) is increasingly used in the United States since approval by the FDA in 2003. RTSA relieves pain and restores mobility in arthritic rotator cuff deficient shoulders. Though many advantages of RTSA have been demonstrated, there still are a variety of complications (implant loosening, shoulder impingement, infection, frozen shoulder) making apparent much still is to be learned how RTSA modifies normal shoulder function. The goal of this study was to assess how RTSA affects deltoid muscle moment generating capacity post-surgery using a subjectspecific computational model driven by in vivo kinematic data.

A Novel Approach To Estimation Of Patient-Specific Muscle Strength, David Walker, Allison Kinney, Benjamin J. Fregly, Thomas Wright, Scott Banks

Mechanical and Aerospace Engineering Faculty Publications

Current modeling techniques have been used to model the Reverse Total Shoulder Arthroplasty (RTSA) to account for the geometric changes implemented after RTSA. Though these models have provided insight into the effects of geometric changes from RTSA these is still a limitation of understanding muscle function after RTSA on a patient-specific basis. The goal of this study sought to overcome this limitation by developing an approach to calibrate patient-specific muscle strength for an RTSA subject.

Development, Characterization, And Optimization Of Process For Minimal Functional Barrier And Channel Width In Nitrocellulose Paper Microfluidic Diagnostic Platforms, Ryan Daniel Silva

Biomedical Engineering

A central goal of diagnostic microfluidics is to reduce the cost of diagnostic medicine by reducing the equipment and reagents needed to perform diagnostic tests. The literature has demonstrated that a wax printer can be used to pattern nitrocellulose paper with hydrophobic barriers to direct a sample in a defined reaction path, eliminating the need for external pumps and controllers. However, manufacturing methods for minimizing sample volume (and thus reagent volume) in a paper-diagnostic chip have not been well defined. In this work, we experimentally determine manufacturing processes for creating functional features of minimal size—effectively reducing the sample size and …

Virus-Host Mucosal Interactions During Early Siv Rectal Transmission, Wuxun Lu, Fangrui Ma, Alexander Churbanov, Yanmin Wan, Yue Li, Guobin Kang, Zhe Yuan, Dong Wang, Chi Zhang, Jianqing Xu, Mark Lewis, Qingsheng Li

Nebraska Center for Biotechnology: Faculty and Staff Publications

To deepen our understanding of early rectal transmission of HIV-1, we studied virus-host interactions in the rectal mucosa using simian immunodeficiency virus (SIV)-Indian rhesus macaque model and mRNA deep sequencing. We found that rectal mucosa actively responded to SIV as early as 3 days post-rectal inoculation (dpi) and mobilized more robust responses at 6 and 10 dpi. Our results suggests that the failure of the host to contain virus replication at the portal of entry is attributable to both a high-level expression of lymphocyte chemoattractant, proinflammatory and immune activation genes, which can recruit and activate viral susceptible target cells into …

Reduced Diaphyseal Strength Associated With High Intracortical Vascular Porosity Within Long Bones Of Children With Osteogenesis Imperfecta, Carolyne Albert, John Jameson, Peter Smith, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Osteogenesis imperfecta is a genetic disorder resulting in bone fragility. The mechanisms behind this fragility are not well understood. In addition to characteristic bone mass deficiencies, research suggests that bone material properties are compromised in individuals with this disorder. However, little data exists regarding bone properties beyond the microstructural scale in individuals with this disorder.

Specimens were obtained from long bone diaphyses of nine children with osteogenesis imperfecta during routine osteotomy procedures. Small rectangular beams, oriented longitudinally and transversely to the diaphyseal axis, were machined from these specimens and elastic modulus, yield strength, and maximum strength were measured in three-point …

Entrepreneurship In Capstone Design: Has The Pendulum Swung Too Far?, Jay R. Goldberg

Biomedical Engineering Faculty Research and Publications

The author supports entrepreneurial education for all interested students, but not at the expense of design education. He thinks we should develop business literacy among all of our students to prepare them for work in start-ups and established medical device companies, and provide opportunities for interested students to add entrepreneurial literacy to better prepare them to create new companies, either upon graduation or later in their careers. Capstone design courses should focus on helping students develop solid design skills and providing opportunities to apply the analytical tools learned in previous courses. Students should be encouraged, not required, to consider commercializing …

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 …

Sensitivity Of Mri-Guided Near-Infrared Spectroscopy Clinical Breast Exam Data And Its Impact On Diagnostic Performance, Michael A. Mastanduno, Junqing Xu, Fadi El-Ghussein, Shudong Jiang, Hong Yin, Yan Zhao, Kelly E. Michaelson, Ke Wang, Fang Ren, Brian W. Pogue, Keith D. Paulsen

Dartmouth Scholarship

In this study, data from breast MRI-guided near infrared spectroscopy (NIRS) exams delivered to 44 patients scheduled for surgical resection (ending in 16 benign and 28 malignant diagnoses) were analyzed using a spatial sensitivity metric to quantify the adequacy of the optical measurements for interrogating the tumor region of interest, as derived from the concurrent MRI scan. Along with positional sensitivity, the incorporation of spectral priors and the selection of an appropriate regularization parameter in the image reconstruction were considered, and found to influence the diagnostic accuracy of the recovered images. Once optimized, the MRI/NIRS data was able to differentiate …

Design And Development Of A Miniature In Vivo Surgical Robot With Distributed Motor Control For Laparoendoscopic Single-Site Surgery, Eric J. Markvicka

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Paradigm shifts in invasiveness, recovery time, cosmesis, and cost have been seen within the field of general surgery through major advances in surgical technology. Some of the most advanced types of general surgery now include Minimally Invasive Surgery (MIS), LaparoEndoscopic Single-Site (LESS) surgery, and Natural Orifice Translumenal Endoscopic Surgery (NOTES). One of the newest and rapidly developing catalysts is robotic platforms. Such platforms have improved ergonomics and control, increased workspace and dexterity, and have surpassed the efficacy of many non-robotic platforms such as traditional laparoscopic surgical tools. This thesis presents the design and development of a four-degree-of-freedom (4- DOF) miniature …

Improvements To Uhmwpe, Brooke Mckelvogue

Journal of Undergraduate Research at Minnesota State University, Mankato

Ultra high molecular weight polyethylene (UHMWPE) is a material used in artificial implants for articular joint replacements. However, these implants have a limited lifespan in which the patient will be pain-free due to the wear of the UHMWPE components. Recently crosslinking, or exposing the material to radiation, has been used to extend the wear resistance of UHMWPE. Crosslinking introduces another set of drawbacks; mainly the reduction of the fracture toughness of UHMWPE and the generation of free radicals, which leave the polymer vulnerable to damage from oxidation. Currently, research is being conducted on other methods to increase the wear resistance …

Computational Model Of A Left Ventricle: Showing The Effects Of Inertia On Cardiac Dyssynchrony, Andrew Mcnally, Matthew Korpela, Erin Lamke, Matthew Hudson

Journal of Undergraduate Research at Minnesota State University, Mankato

In an effort to research heart failure, a leading cause of death in the industrialized world, this research team has developed a segmented lumped parameter model of the left ventricle. The computations model developed focuses on dyssynchrony, a heart condition where some regions of the heart vary significantly in properties like internal muscle resistance, mass, or elastance. Inertial effects are often assumed as negligible by cardiovascular models. One primary function of this model is to investigate inertial effects as they relate to mechanical cardiac dyssynchrony. An added dimension of this analysis is to observe the thermodynamics of the cardiac cycle …

A Three-Dimensional In Vitromodel Of Atherogenesis, Pin Hsuan Chang

Theses and Dissertations

Atherosclerosis is the narrowing of arteries caused by accumulation of cholesterol, calcium and other cellular debris in the inner arterial wall. While extensive studies have been focusing on the inflammatory mechanisms of the disease, pathological and experimental evidence has shown that regions of disturbed flow are susceptible to the atherogenesis. To further understand the relationship between hemodynamics and atherogenesis, this research aims to generate a dynamic, 3D in vitro model of atherogenesis. This will allow for the investigation of specific cellular and molecular mechanisms of plaque formation that will pave the way for new therapies for the disease. A novel …

Developing A Bioreactor For Biaxial Mechanical Testing And Conditioning Of Vascular Tissue, Steve Marcous

Theses and Dissertations

Cardiovascular diseases are known to be one of the major causes of death around the world. One of the major causes of cardiovascular disease is arterial malfunction. Arteries malfunction when they experience chronic perturbations in their local environment above normal levels. Hence, we developed a bioreactor system in order to study the effect of chronic changes in the arterial global parameters (axial force, luminal pressure, and flow rate) on the behavior of local parameters (circumferential stress, axial stress, and flow induced shear stress). The bioreactor system was designed to (i) perform biaxial mechanical testing, (ii) incorporate, for the first time, …

Biological Implications Of Satellite Cells For Scaffold-Based Muscle Regenerative Engineering, Maggie R. Del Ponte, Charter Chain, Meng Deng Dr., Feng Yue Dr., Shihuan Kuang Dr.

The Summer Undergraduate Research Fellowship (SURF) Symposium

Satellite cells are anatomically localized along the surface of muscle fibers and have been regarded as a population of muscle-specific progenitors that are responsible for muscle regeneration. In response to muscle injuries, satellite cells are activated to enter the cell cycle, then proliferate and differentiate into mature muscle cells to regenerate damaged myofibers. Unfortunately, this natural repair mechanism is interrupted in conditions such as muscle degenerative diseases or volumetric muscle loss. The function of stem cells is regulated by signals from their local microenvironment which is called the stem cell niche. Current satellite cell-based strategies such as direct cell transplantation …

Using Collagen Binding Poly(N-Isopropylacrylamide) Nanoparticles To Prevent Intravascular Platelet Adhesion And Activation, Anna E. Searle, Alyssa Panitch, James Mcmasters

The Summer Undergraduate Research Fellowship (SURF) Symposium

Balloon angioplasty, the most prevalent non-surgical treatment for Atherosclerosis, damages the endothelial layer of the artery, baring an underlying collagenous layer, which causes platelet adhesion and activation and eventual thrombosis and intimal hyperplasia. Previous work in our lab has used a collagen-binding peptidoglycan, dermatan-sulfate-SILY (DS-SILY), that has been shown to bind to type I collagen and prevent platelet adhesion and activation. Our goal is to fabricate nanoparticle-SILY by cross-linking SILY to a poly(N-isopropylacrylamide) (NIPAm) nanoparticle instead of a DS backbone, while retaining the SILY’s high collagen binding affinity and platelet inhibition capacity observed in DS-SILY. Using a biotin-streptavidin assay, we …

Optimization Of Imaging Parameters To Determine Flow Velocity Using Nanoparticles, Sabrina M. Scalf, Haisheng Yang, Russell P. Main

The Summer Undergraduate Research Fellowship (SURF) Symposium

Microfluidic flow chambers have been developed and used to measure flow at the microscopic level. Nanoparticles can be used to track the fluid flow within the chamber and this allows for accurate velocity measures. Microscope parameters used for experimentation differ across various projects and resources; therefore, there is a need to determine the best combination of settings for the equipment at hand. Once appropriate settings are selected, images of the flow are captured with a confocal microscope and can be analyzed using custom written MATLAB code. A pair cross-correlation function is used to determine where the particles have traveled in …

Spatiotemporal Changes In Nuclear Strain Measured By Traction Force Microscopy, Ryan D. Watts, Corey Neu, Jonathan Henderson

The Summer Undergraduate Research Fellowship (SURF) Symposium

The knowledge of how cells interact with and sense their surroundings is missing the key components of time dependency and how substrate stiffness affects amount and rate of strain. This new knowledge of cell-substrate interaction can be applied further to research regarding chromatin spatiotemporal dynamics to better understand gene accessibility for transcription. Studying how the cell functions on a deeper level will provide understanding of cellular morphological changes and proliferation. This study uses the methods of optical microscopy and traction force microscopy (TFM) to image substrate deformation as well as analyze its strain profile to find where forces are interacting …