Other Biomedical Engineering and Bioengineering Commons^™

5ht And The 5ht Receptors- Relevance To Cardiac Valve Disease, Christopher Ryan Martindale

Biomedical Engineering Undergraduate Honors Theses

Recent studies have revealed that elevated levels of serotonin or 5HT lead to valve dysfunction. A mouse model was successfully established to investigate the effects on the aortic valve in subjects with elevated 5HT levels along with cardiovascular hypertension. For each two-week trial, eight C57BL/6J mice were divided into the following expermental groups: control, 5HT, angiotensin II, and 5HT+angiotensin II. The drug was delivered to the mice via osmotic pumps (Ang II: 0.4ng/g/min, 5HT:0.0025ng/g/min) or direct injections(Ang II: 0.1 mg, 5HT: 2.12 mg, every other day) and the blood pressure of the mice was continually monitored via the CODA tail …

Modeling Of An Oxygenation-Aided 3d Culture For Functional Beta-Cell Expansion, John Lance Mcreynolds

Biomedical Engineering Undergraduate Honors Theses

Introduction: Diabetes affects millions of people and its prevalence is increasing by 2-5% per year. A promising method for the control of diabetes is the transplant of pancreatic β-cell mass. Unfortunately, there is a shortage of the donor tissue that is needed to replace β-cell mass. A potential source of β-cells is the production of β-cells in vitro, but the proliferation rate of β-cells is very slow and elevating the proliferation rate can result in loss of cell function. We observed that β-cells benefit from being cultured in a 3D environment, but in the 3D culture the β-cells often die …

Beginning Of Malignant Tumor Cells, Emily K. Shields

Biomedical Engineering Undergraduate Honors Theses

Despite advances in cancer treatments, cancer is still ranked the second leading cause of death. Cancers are started by cancer stem cells (CSCs). CSCs, also called tumor-initiating cells, are found in tumors and are responsible for the growth of tumors and the spread of cancer to other parts of the body. CSCs are very resistant, and cannot be killed by chemotherapy or radiation treatments. These cells can come from healthy stem cells. The environment surrounding the healthy stem cells and mature cells can cause mutations in the cell’s genetics, resulting in development of CSCs. The environment can also increase tumor …

Investigating The Shelf Life Of Benzoyl Peroxide Coated Nozzles For Bone Cement Application, Alysen Leigh Demzik

Renée Crown University Honors Thesis Projects - All

Two-solution bone cements (TSBC) were developed to address the limitations of current powder-liquid bone cements, however are characterized by a limited shelf life due to spontaneous free radical polymerization. As a solution to pre-polymerization concerns, the initiator benzoyl peroxide (BPO) was removed from the cement solution and incorporated into a thin film coating within the static mixing nozzle, allowing the BPO to integrate with the TSBC as it is mixed for use. Only short-term storage of BPO-coated nozzles and the subsequent effects on bone cement properties is known. The goal of this study was to investigate the effects of time, …

Application Of Limited Mixing In The Hele–Shaw Geometry In Fabrication Of Janus Hydrogels, Md Mahmudur Rahman

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

It is widely accepted that cells behave differently responding to the stiffness of their extracellular matrix (ECM). Such observations were made by culturing cells on hydrogel substrates of tunable stiffness. However, it was recently proposed that cells may sense how strongly they are tethered to ECM, not the local stiffness of ECM. To investigate both hypotheses, we developed a method to fabricate Janus polyacrylamide (PAAM) gels. We squeeze two drops of different concentrations in the Hele-Shaw geometry to generate radial Stokes flow. When the drops coalesce, limited mixing occurs at the interface due to the narrow confinement, and diffusion normal …

Material Differences In Equine Cortical And Trabecular Bone, Ryan B. Allen

Master's Theses

A greater understanding of bone materials would be beneficial in creating more accurate computer models and in the making of biomedical products involving bone. This study set out to determine whether cortical and trabecular bone are two separate materials, or whether they are the same material with a variance in porosity. To answer this question, samples were taken from different sections of the equine metacarpus, underwent densitometry analysis and were statistically analyzed. The majority of results suggest that the material is the same between varying densities of bone and thus the same between cortical and trabecular bone. These particular results …

From Cardiac Optical Imaging Data To Body Surface Ecg: A Three Dimensional Ventricle Model, Yihua Zhao

Theses and Dissertations--Biomedical Engineering

Understanding the mechanisms behind unexplained abnormal heart rhythms is important for diagnosis and prevention of arrhythmias. Many studies have investigated the mechanisms at organ, tissue, cellular and molecular levels. There is considerable information available from tissue level experiments that investigate local action potential properties and from optical imaging to observe activity propagation properties at an organ level. By combining those electrophysiological properties together, in the present study we developed a simulation model that can help in estimation of the resulting body surface potentials from a specific electrical activity pattern within the myocardium. Some of the potential uses of our model …

Novel Technologies For The Detection And Mitigation Of Drowsy Driving, Samuel Lawoyin

Theses and Dissertations

In the human control of motor vehicles, there are situations regularly encountered wherein the vehicle operator becomes drowsy and fatigued due to the influence of long work days, long driving hours, or low amounts of sleep. Although various methods are currently proposed to detect drowsiness in the operator, they are either obtrusive, expensive, or otherwise impractical. The method of drowsy driving detection through the collection of Steering Wheel Movement (SWM) signals has become an important measure as it lends itself to accurate, effective, and cost-effective drowsiness detection. In this dissertation, novel technologies for drowsiness detection using Inertial Measurement Units (IMUs) …

Analysis And Modeling Of The Roles Of Actin-Myosin Interactions In Bladder Smooth Muscle Biomechanics, Seyed Omid Komariza

Theses and Dissertations

Muscle mechanical behavior potentially plays an important role in some of the most common bladder disorders. These include overactive bladder, which can involve involuntary contractions during bladder filling, and impaired contractility or underactive bladder, which may involve weak or incomplete contractions during voiding. Actin-myosin cross-bridges in detrusor smooth muscle (DSM) are responsible for contracting and emptying the bladder. The total tension produced by muscle is the sum of its preload and active tensions. Studies suggest that actin-myosin cross-links are involved in adjustable preload stiffness (APS), which is characterized by a preload tension curve that can be shifted along the length …

The Effect Of Various Pathologies On Bone Quality, Daniel S. Porter

Theses and Dissertations--Biomedical Engineering

Bone’s ability to resist fracture is often ignored until a low-energy fracture occurs. Patients with Chronic Kidney Disease (CKD) or osteoporosis are at an increased risk of low-energy fracture. Generally, fracture risk is evaluated by using a bone mineral density (BMD) test. BMD values; however, do not fully predict bone’s ability to resist fracture. This suggests that other parameters may be involved. Bone quality is the term used to describe these parameters, which are categorized into three groups: structural, material, and microdamage. The aim of this dissertation research was to examine whether bone quality was altered in patients who: 1) …

Human Cardiovascular Responses To Artificial Gravity Variables: Ground-Based Experimentation For Spaceflight Implementation, Mark Howarth

Theses and Dissertations--Biomedical Engineering

One countermeasure to cardiovascular spaceflight deconditioning being tested is the application of intermittent artificial gravity provided by centripetal acceleration of a human via centrifuge. However, artificial gravity protocols have not been optimized for the cardiovascular system, or any other physiological system for that matter. Before artificial gravity protocols can be optimized for the cardiovascular system, cardiovascular responses to the variables of artificial gravity need to be quantified.

The research presented in this document is intended to determine how the artificial gravity variables, radius (gravity gradient) and lower limb exercise, affect cardiovascular responses during centrifugation. Net fluid (blood) shifts between body …

Mechanical Properties Of Bone Due To Sost Expression: Nanoindentation Assessment Of Murine Femurs, Amir Rafie

Master's Theses

In the human genome, the SOST gene codes for a protein sclerostin. Sclerostin is an osteocyte-expressed negative regulator of bone formation. When the SOST gene is not coded, bone formation is reduced in individuals during skeletal maturation. This study utilizes nanoindentation methods to test for the mechanical properties of bones that both express and do not express the SOST gene. 100 transgenic murine femurs were obtained from Lawrence Livermore Labs in the form of 6 and 8 month SOST transgenic mice, 6 and 12 month SOST knockout mice, and wild type control littermates for each of the 4 age groups. …

Physiological Fluid Specific Agglomeration Patterns Diminish Gold Nanorod Photothermal Characteristics, Kristen K. Comfort, Jared W. Speltz, Bradley M. Stacy, Larry R. Dosser, Saber M. Hussain

Chemical and Materials Engineering Faculty Publications

Investigations into the use of gold nanorods (Au-NRs) for biological applications are growing exponentially due to their distinctive physicochemical properties, which make them advantageous over other nanomaterials. Au-NRs are particularly renowned for their plasmonic characteristics, which generate a robust photothermal response when stimulated with light at a wavelength matching their surface plasmon resonance. Numerous reports have explored this nanophotonic phenomenon for temperature driven therapies; however, to date there is a significant knowledge gap pertaining to the kinetic heating profile of Au-NRs within a controlled physiological setting. In the present study, the impact of environmental composition on Au-NR behavior and degree …

In Vivo Method For Labeling And Tracking Cells In The Mammalian Limb Bud, James T. Mccarthy, Andrew Schilb, Sarah Calve

The Summer Undergraduate Research Fellowship (SURF) Symposium

The extracellular matrix (ECM) is composed of many different proteins excreted by cells and is believed to play a very important role in development as well as regeneration and wound healing. In this research, a method to determine the ECM’s effect on the migration of muscle progenitor cells into the mammalian limb bud was investigated. It has traditionally been difficult to obtain in vivo images of the limb bud, due to the difficulty of maintaining embryos in culture and limitations of imaging techniques. In this study, we have worked on optimizing the culture conditions to allow growth of mouse embryos …

The Effects Of Exogenous Extracellular Matrix And Substrate Stiffness On Mouse Tendon Cells In Vitro, Caleb J. Mcdaniel, Sarah Calve

The Summer Undergraduate Research Fellowship (SURF) Symposium

To improve the treatment of musculoskeletal injuries, a better understanding of the transitional environment in which progenitor cells form mature musculoskeletal constructs is necessary. This need arises because injury repair requires restructuring of tissue, similar to the initial tissue construction that occurs during embryonic development by progenitor cells. Differences in both the biochemical and mechanical environments between a transitional and a differentiated state are known to take place, but how these differences affect cell behavior had not yet been characterized in mammalian tendon cells. In order to investigate this, we have determined the effects of exogenous extracellular matrix and the …

Halloysite Nanotube Composites For Sustained Release Of Antimocrobial Agents (Antiseptics And Antibiotics), Wenbo Wei

Doctoral Dissertations

Encapsulation of antimicrobial agents (simple antiseptics and more specific antibiotics) within micro-scale and nano-scale containers may provide prolonged and more evenly distributed drug release. One of such containers proposed at Louisiana Tech is natural halloysite clay nanotubes. Halloysite is an aluminosilicate tube with a length of approximately 1 µm, outer diameter of approximately 50 nm, and internal lumen of 15 nm. The chemical composition of halloysite is similar to more common clay–kaolinite, and it can be described as rolled sheets of kaolinite. Halloysite, loaded with drugs inside its lumen, has shown aqueous release of the loaded chemicals over 10-20 hours …

Sequential Structural And Fluid Dynamics Analysis Of Balloon-Expandable Coronary Stents., David Martin

Doctoral

As in-stent restenosis following coronary stent deployment has been strongly linked with stent-induced arterial injury and altered vessel hemodynamics, the sequential numerical analysis of the mechanical and hemodynamic impact of stent deployment within a coronary artery is likely to provide an excellent indication of coronary stent performance. Despite this observation, very few numerical studies have considered both the mechanical and hemodynamic impact of stent deployment. In light of this observation, the aim of this research is to develop a robust numerical methodology for investigating the performance of balloon-expandable coronary stents in terms of their mechanical and hemodynamic impact within a …

Modeling And Control Of Nanoparticle Bloodstream Concentration For Cancer Therapies, Scarlett S. Bracey

Doctoral Dissertations

Currently, the most commonly used treatments for cancerous tumors (chemotherapy, radiation, etc.) have almost no method of monitoring the administration of the treatment for adverse effects in real time. Without any real time feedback or control, treatment becomes a "guess and check" method with no way of predicting the effects of the drugs based on the actual bioavailability to the patient's body. One particular drug may be effective for one patient, yet provide no benefit to another. Doctors and scientists do not routinely attempt to quantifiably explain this discrepancy. In this work, mathematical modeling and analysis techniques are joined together …

An Analysis Of Eliminating Electroosmotic Flow In A Microfluidic Pdms Chip, Cecile D. Redington

Master's Theses

The goal of this project is to eliminate electroosmotic flow (EOF) in a microfluidic chip. EOF is a naturally occurring phenomenon at the fluid-surface interface in microfluidic chips when an electric field is applied across the fluid. When isoelectric focusing (IEF) is carried out to separate proteins based on their surface charge, the analytes must remain in the separation chamber, and not migrate to adjacent features in the microfluidic chip, which happens with EOF.

For this project, a microfluidic chip was designed and commissioned to be photolithographically transferred onto a Si wafer. A PDMS component was then casted on the …

Vascular Reactivity Of Immature Arterialized Capillaries, Sara Hellstrom

Biomedical Engineering

Peripheral arterial occlusive disease (PAOD) is a globally prevalent cardiovascular disease in which atherosclerotic plaques narrow arterial lumen diameters and restrict blood flow to down stream tissues. The impact of these occlusions can be mitigated by collateral vessels that connect parallel arterial branches and act as natural bypasses to maintain perfusion. Some patients with PAOD may not have robust collateral networks to accommodate ischemic tissues in the event of an occlusion and, therefore, may be more susceptible to hypoxia and tissue necrosis. In animal models that lack collateral arterioles, capillaries can arterialize and form functional collaterals; however, in the early …