Biomedical Engineering and Bioengineering Commons^™

Fractionation And Characterization Of Lignin Streams From Genetically Engineered Switchgrass, Enshi Liu

Theses and Dissertations--Biosystems and Agricultural Engineering

Development of biomass feedstocks with desirable traits for cost-effective conversion is one of the main focus areas in biofuels research. As suggested by techno-economic analyses, the success of a lignocellulose-based biorefinery largely relies on the utilization of lignin to generate value-added products, i.e. fuels and chemicals. The fate of lignin and its structural/compositional changes during pretreatment have received increasing attention; however, the effect of genetic modification on the fractionation, depolymerization and catalytic upgrading of lignin from genetically engineered plants is not well understood. This study aims to fractionate and characterize the lignin streams from a wild-type and two genetically engineered …

Shape Memory Behavior Of Dense And Porous Niti Alloys Fabricated By Selective Laser Melting, Soheil Saedi

Theses and Dissertations--Mechanical and Aerospace Engineering

Selective Laser Melting (SLM) of Additive Manufacturing is an attractive fabrication method that employs CAD data to selectively melt the metal powder layer by layer via a laser beam and produce a 3D part. This method not only opens a new window in overcoming traditional NiTi fabrication problems but also for producing porous or complex shaped structures. The combination of SLM fabrication advantages with the unique properties of NiTi alloys, such as shape memory effect, superelasticity, high ductility, work output, corrosion, biocompatibility, etc. makes SLM NiTi alloys extremely promising for numerous applications.

The SLM process parameters such as laser power, …

A Stationary Camera For Use With Other Implantable Medical Devices, Ariane Garrett

Holster Scholar Projects

I designed an optical system for analysis of implantable devices. The final system consists of a 3mm double convex lens that focuses a light spot onto a tissue or implantable medical device. This light spot can then provide feedback on the movement of flow through a device or the development of tissue on the device, although my project focused solely on the flow application. The light spot is generated by an LED and directed using a half mirror. It is then focused using a ball lens, fiber optic, and the double convex lens. With this system the generated light spot …

Structural Characteristics And Corrosion Behavior Of Bio-Degradable Zn-Li Alloys In Stent Application, Shan Zhao

Dissertations, Master's Theses and Master's Reports

Zinc has begun to be studied as a bio-degradable material in recent years due to its excellent corrosion rate and optimal biocompatibility. Unfortunately, pure Zn’s intrinsic ultimate tensile strength (UTS; below 120 MPa) is lower than the benchmark (about 300 MPa) for cardiovascular stent materials, raising concerns about sufficient strength to support the blood vessel. Thus, modifying pure Zn to improve its mechanical properties is an important research topic.

In this dissertation project, a new Zn-Li alloy has been developed to retain the outstanding corrosion behavior from Zn while improving the mechanical characteristics and uniform biodegradation once it is implanted …

The Impact Of Active Aerodynamics On Motorcycles Using Computational Fluid Dynamics Simulations, Aditya Sripathi

All Graduate Theses, Dissertations, and Other Capstone Projects

Motorcycles are mostly utilized by commuters whose requirements are cheap and affordable transportation from point A to point B. Motorcycles also provide means to tour various places and have a leisure time for the majority of motorcyclists. Unfortunately, with pros also come cons such as accidents which are disabling or life-taking. According to motorcycle crash statistics produced every year, the majority of motorcycle crashes are caused due to facing unexpected obstacles in the path causing collisions due to insufficient braking time. Thus, this thesis serves as a mean to overcome this issue and provide a technological solution to the world …

Oxygen Transport In Carotid And Stented Coronary Arteries, Eoin A. Murphy

Doctoral

Oxygen deficiency, known as hypoxia, in arterial walls has been linked to increased intimal hyperplasia, which is the main adverse biological process causing in-stent restenosis. Stent implantation can have significant effects on the oxygen transport into the arterial wall. Helical flow has been theorised to improve the local haemodynamics and the oxygen transport within stented arteries. In this study an advanced oxygen transport model was developed to assess different stent designs. This advanced oxygen transport model incorporates both the free and bound oxygen contained in blood and includes a shear-dependent dispersion coefficient for red blood cells. In two test cases …

Computational Studies On Biomechanics Of Concussion And On Efficacy Of Football Helmets, David Labyak

Dissertations, Master's Theses and Master's Reports

Football helmets have been used for many years to prevent head injuries to players. Over the years, the helmet design has evolved from a crude leather head covering to the more recent form fitting helmets that are seen today. The one design feature that has been common in the majority of all helmets is a hard polycarbonate shell with a foam cushion padding. The main goal of the padding layer was to reduce the amount of linear acceleration during an impact event. The one feature that has been overlooked is how stiff the padding is in rotation.

The purpose of …

Formulation And Testing Of Biodegradable Polymeric Coating On Zinc Wires In Cardiovascular Stent Application, Avishan Arab Shomali

Dissertations, Master's Theses and Master's Reports

Biodegradable and biocompatible poly (L-lactic-acid) (PLLA) coating was applied on a modified zinc (Zn) substrate by dip coating, with the intent to delay the bio-corrosion and slow the degradation rate of zinc substrate. 3-(Trimethoxysilyl) propyl methacrylate (MPS) was used for modification of the zinc substrate for promoting the adhesion between the metallic substrate and the polymer coating. It is hypothesized that the delay in Zn biodegradation could be useful in the first several weeks to prevent the early loss of mechanical integrity of the endovascular stent and to improve the healing process of the diseased vascular site. The PLLA coating …

Analytical-Based Methodologies To Examine In Vitro Nanokinetics Of Silver Nanoparticles, Sesha Lakshmi Arathi Paluri

Browse all Theses and Dissertations

Advancements in the nanotechnology have taken a huge leap in 21st century resulting in 1814 consumer products containing nanomaterials. About 47% of these products belong to the health and fitness sector and ~24% utilize silver nanoparticles (AgNPs). Despite the promising biomedical applications of AgNPs (e.g. bone cements, contrasting agents, and drug-carriers), lack of standardized methods for examining their nanokinetics (i.e., Absorption, Distribution, Metabolism, and Elimination (ADMEs)) limit their clinical implementation. The current work addresses this knowledge gap by developing analytical-based approaches for studying in vitro ADMEs of AgNPs. To demonstrate the versatility of these methodologies, two in vitro kidney study …

Dysregulation Of Phospholipase D (Pld) Isoforms Increases Breast Cancer Cell Invasion, Kristen Fite

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Breast cancer remains the second most prevalent cancer among women in the U.S. with metastatic breast cancer having the worst prognosis. A rapidly proliferating tumor under various stressors will promote phenotypic cellular changes, known as epithelial-to-mesenchymal transition (EMT), which allows cells to begin to invade surrounding tissue, enter the circulatory system, and eventually seed a distant metastatic site. The phospholipase D (PLD) enzymes are critical regulators of cell signaling pathways necessary for cell migration. While the importance of PLD enzymes in cancer cell invasion is well known, clinically applicable methods of PLD inhibition are not yet available. The best-studied isoforms …

The Analysis Of Pediatric Sleep Lab Inefficiencies, Jessica Buehler, Autumn Barkley, Caitlin Dickerson, Andrew Fosnight, Omar Saad

Williams Honors College, Honors Research Projects

The goal of this project is to develop a children’s sleep apnea test for home use. This design is to be of cost and quality improvement to what is currently on the market. It is important to fully understand the background of this sleep disorder in order to create this improvement. Knowing what sleep apnea is, as well as the different types, is what is used to create the methods such as S.C.O.P.E.R. Each letter is used to observe one portion or aspect of the human body and how it functions with regards to sleep apnea. The data taken from …

Local Probability Based Transformations And Diagonal Projection: A New Support Vector Machine-Like Method For Classification Of Feature Vectors, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Working Papers

No abstract provided.

Characterization Of Polyurethane For Use As Substrate In Nanofiber Sensor For Biomedical Applications, Megan Theaker

Williams Honors College, Honors Research Projects

The purpose of this project is to begin to determine properties of polymer nanocomposites that make a suitable substrate for nanofiber sensors. In this work, sensitivity of a sodium ion selective sensor constructed with polyurethane was used as a benchmark for comparison with sensors constructed with nylon-6. The sensors were characterized using contact angle and chronoamperometry. Using an ANOVA analysis, the results showed that the multi-walled carbon nanotube type was a significant factor on sensor response both with and without additional functionalization of the polymer by calixarene. The weight percentage of polyurethane in the electrospinning solution was also statistically significant …

Meta-Analysis Of Studies On Cpr: A Better Route To New Practice Guidelines, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Working Papers

Quantitative synthesis of research results multiple small clinical trials using the statistical techniques of meta-analysis yields conclusions in excellent agreement with large randomized “mega-trails”. The present paper introduces a simple yet powerful method of meta-analysis for combining results of any published studies of a proposed treatment compared with a suitable control. These may include pre-clinical or clinical models generating either continuous or dichotomous data.

Increased Risk Of Children For Subtle Closed Head Injury From Soccer Heading, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Working Papers

No abstract provided.

Valveless Pumping: The Reflected Pulse Wave Hypothesis, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Working Papers

No abstract provided.

Developing Afm Techniques For Testing Peg Hydrogels, Hannah L. Cebull, Jessica Stukel, Rebecca Willits

Williams Honors College, Honors Research Projects

Many instruments are used to find elastic properties of biological samples using methods such as tensile and bending tests, but using the atomic force microscope (AFM) is considered a non-destructive method because it can provide repeated local stiffness information without damaging the sample. It additionally allows the sample to be tested in an aqueous environment, which is optimal for soft materials such as hydrogels. The nanoindentation is performed via cantilever, measuring the deflection of the cantilever during the contact of the sample using a laser. Compared to hard samples, testing soft materials can present more challenges when working with the …

Identification Of Novel Ligands And Structural Requirements For Heterodimerization Of The Liver X Receptor Alpha, Shimpi Bedi

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LXRs, LXRa (NR1H3) and LXRß (NR1H2), are ligand-activated transcription factors that are members of the nuclear receptor superfamily. Oxysterols and nonsteroidal synthetic compounds bind directly to LXRs and influence the expression of LXR dependent genes. The use of murine models and LXR-selective agonists have established the important role of LXRs as sterol sensors that govern the absorption, transport, and catabolism of cholesterol. Upon activation, these receptors have been shown to increase reverse cholesterol transport from the macrophage back to the liver to aid in the removal of excess cholesterol. Not surprisingly, LXR dysregulation is a feature of several human diseases, …

A Novel System For Detection Of Dna Double Strand Breaks And Repair In Human Cells, Todd Warren Lewis

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Imperative to genomic stability is the ability of the cell to repair damaged DNA which can occur from numerous endogenous byproducts of metabolism or exogenous components from the environment. The Fanconi anemia pathway is a DNA repair mechanism used by human cells to resolve multiple forms of DNA damage including interstrand crosslinks (ICL). Fanconi anemia (FA) is an autosomal recessive inherited disorder characterized by genome instability, developmental abnormalities, cancer predisposition and bone marrow failure. FA is attributed to a mutations in at least 18 genes (FANCA-FANCT) that play a concerted role in DNA repair. FANCT is the latest discovery in …

Persistent Inward Currents Play A Role In Muscle Dysfunction Seen In Myotonia Congenita, Ahmed Alaa Hawash

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Myotonia congenita is a rare skeletal muscle channelopathy caused by a reduced chloride channel (ClC-1) current, which results in debilitating muscle hyperexcitability, prolonged contractions, and transient episodes of weakness. The excitatory events that trigger myotonic action potentials in the absence of stabilizing ClC-1 current are not fully understood. My in vitro intracellular recordings from a mouse homozygous knockout of ClC-1 revealed a slow after-depolarization (AfD) that triggers myotonic action potentials. The AfD is well-explained by a tetrododoxin-sensitive and voltage-dependent Na+ persistent inward current (NaPIC). Notably, this NaPIC undergoes slow inactivation over seconds, thus providing the first mechanistic explanation for the …