Engineering Commons^™

In Vivo Flow Measurements Of Murine Renal Arteries And Veins With High Frequency Ultrasound, Amy E. Bogucki, Hilary D. Schroeder, Alexa A. Yrineo, Craig J. Goergen

The Summer Undergraduate Research Fellowship (SURF) Symposium

The number of glomeruli in the kidneys has been shown to have an effect on the decline in renal function over time (Brenner, Garcia, Anderson 1988). Furthermore, flow in the renal arteries and veins may depend on the number of glomeruli in the kidney. Consistent in vivo measurements of volumetric flow in the renal arteries and veins are difficult to obtain. Thus, the purpose of this study was to develop non-invasive imaging techniques capable of estimating arterial and venous flow to kidneys. A high-frequency small animal ultrasound system was chosen based upon its excellent spatial and temporal resolution when imaging …

Determination Of Master Compliance Curve For Extruded Semolina Pasta, Laura E. Emery, Martin Okos

The Summer Undergraduate Research Fellowship (SURF) Symposium

The dependence of the rate of relaxation of semolina pasta on moisture content and temperature and how it affects shrinkage during drying has not yet been determined. The purpose of this research was to develop an equation that relates moisture content and temperature in order to obtain a master curve for creep of the product. When found, this equation could help to optimize the drying process and increase the quality of the final pasta product. Semolina flour mixed with water and propionic acid to create a 35% wet basis product was extruded on a C.W. Brabender 2523 to obtain a …

Artificial Yeast Polarization Controlled By Chemical Gradient, James K. Nolan, Bernard Tao

The Summer Undergraduate Research Fellowship (SURF) Symposium

Engineering synthetic multicellular systems will lead to new synthetic biology technological platforms, inform developmental biology through recapitulation of natural systems and possibly unveil novel morphologies with practical applications not before reached throughout natural history (Maharbiz, 2012). Creating an exogenous molecular circuit that will polarize unicellular cells into “apical” and “basal” domains relative to a substrate plane would fulfill a missing component towards fully multicellular synthetic cellular communities (Maharbiz, 2012). To this end, a PIP₃ polarization network previously designed by Chau and associates (Chau, Walter, Gerardin, Tang, Lim 2012) was coupled to the specific activation by niacin of a recombinant …

The Efficacy And Optimization Of Somatosensory Intracortical Microstimulation In Rats, Sean P. Mcdowell, Ryan S. Verner, Kevin J. Otto Dr.

The Summer Undergraduate Research Fellowship (SURF) Symposium

Demand exists for brain-machine interfaces that offer a wide range of sensory feedback along with volitional motor control to individuals with limited control of natural sensory or motor function. As these sensorimotor devices are developed, it is necessary to improve the interaction between the prostheses and higher-level cortical structures. Optimizing these somatosensory stimulation parameters will require the use of a high-throughput experimental design. To address this, one Sprague-Dawley rat was trained to respond to auditory stimuli during a conditioned-avoidance behavior task and then implanted with a penetrating microelectrode array in the part of the somatosensory cortex corresponding to the left …

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 …

Visualization Of Complex Flow Patterns In Angiotensin Ii-Induced Dissecting Murine Abdominal Aortic Aneurysms With High Frequency Ultrasound, Hilary D. Schroeder, Alexa A. Yrineo, Amy E. Bogucki, Craig J. Goergen

The Summer Undergraduate Research Fellowship (SURF) Symposium

Abdominal aortic aneurysm (AAA) rupture is a common cause of mortality in the United States. Current treatments are only employed once the risk of rupture outweighs the risks associated with surgery. Murine models have been developed to characterize AAA pathogenesis in the hope that new treatments will be developed. For this study, angiotensin II (AngII) was infused subcutaneously into apolipoprotein E-deficient (ApoE^-/-) mice using an osmotic mini-pump over 28 days. ApoE^-/- mice (16-week-old, 3 females, 2 males) were imaged using a VisualSonics Vevo 2100 high frequency ultrasound before pump implantation and 3, 7, 14, 21, and 27 …

Image Skeletal Muscle Progenitors In Situ To Investigate How The Ecm Composition Regulates Musculoskeletal Assembly, Andrew L. Schilb, Sarah Calve

The Summer Undergraduate Research Fellowship (SURF) Symposium

Regenerative medicine has difficulty with the human body’s inability to functionally repair tissues lost as a result of disease or serious accident. Through tissue engineering, there has been development of various scaffolding with the purpose of enhancing skeletal muscle regrowth and functionality. The scaffolds are typically constructed from artificial polymers or decellularized extracellular matrix (ECM) that mimics adult tissue. These standardized scaffolds are hindered though by the host since tissue engineers have not taken into account of how the composition musculoskeletal ECM during tissue repair is dramatically different than that of a homeostatic adult. Now green fluorescent protein positive (GFP+) …

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 …

Wireless Myoelectric Sensor Minimization And Packaging, Ásbjörg Einarsdóttir, Pedro Irazoqui Dr.

The Summer Undergraduate Research Fellowship (SURF) Symposium

Many people suffer from amputation, which affects their lives severely by disabling them from doing chores in their daily life as well as chores related to work and leisure. For the last years, prosthetics’ development has been fast and the devices that are being used now are a miracle compared to what has been used before. But still, the battle is not over yet. Although scientists have techniques and devices to use nerve residues from the amputated limb to control the prosthetic, smaller devices that can detect the signals from those nerves better need to be developed. In this research …

Toward An Optogenetic Autonomous Nerve Control (Oanc) System, Malika S. Datta, Matthew Ward, Steven Lee, Kevin Seburn, Pedro Irazoqui

The Summer Undergraduate Research Fellowship (SURF) Symposium

Optogenetics is a developing field in neuroscience, where nerves are stimulated through optical instead of electrical signals, allowing for a more selective action of nerve populations [Aravanis et al, 2007]. In the context of electrical stimulation, the autonomous nerve control (ANC) system has been used successfully, first to map the response of different nerve fibers to create a Nerve Activation Profile, and then to use this profile in recruiting specific nerve fibers in a controlled way [MP Ward et al, unpublished manuscript in preparation]. The objective of the present project is to apply the ANC system to optical stimulation thus …

Inkjet Printing Of Polarized Yeast Cells, Xiuyuan Yang, Kari Clase

The Summer Undergraduate Research Fellowship (SURF) Symposium

The motivation is to applying engineering knowledge to develop 3D bio-printing in inkjet printer (first stage--monolayer). To achieve the goal, there are three problems to solve. First, we have to figure out regulation of growth of target cells; inability to regulate the location and pattern of growing cells make us even unable to build 3D printer in the direct way. Second problem is how to protect of yeast cells from high temperature and viscous force when printing. The third issue is how to modify the inkjet printer especially the feeding system in order to implement printing on other materials rather …

Adhesive Elastomeric Proteins, Haefa Mansour, Julie Liu

The Summer Undergraduate Research Fellowship (SURF) Symposium

Sutures and staples commonly used to close surgical wounds tend to be much stiffer than the surrounding tissue, often resulting in external tissue damage. Surgical adhesives provide a promising alternative to these sutures and staples. Ideal surgical adhesives are biocompatible, able to set well and remain sticky in moist conditions, possess strong adhesive and cohesive properties, and exhibit mechanical properties that mimic those of the surrounding tissue. Unfortunately, the adhesives available today are unable to satisfactorily meet all of these criteria. We are utilizing protein engineering techniques to design, create, and test a new surgical adhesive that combines the adhesive …

A Quantitative Analysis Of A Paper-Based, Laser-Defined, Oxygen-Generating Platform For Chronic Wounds, Tiffany L. Huang, Babak Ziaie

The Summer Undergraduate Research Fellowship (SURF) Symposium

Chronic wounds affect 6.5 million patients a year while consuming US$25 billion in health care costs (Sen 2009 Wound Repair Regen.). Despite advances in wound management therapies, modern treatment for chronic wounds still requires continual professional attention and expensive equipment, posing serious practical and financial burdens for the regular patient. To provide an alternative solution, we are developing a low-cost smart bandage platform that integrates actuators and sensors to monitor and treat chronic wounds. One component of the integrated platform is an oxygen-generating module. It is a polydimethylsiloxane (PDMS) based microfluidic device fabricated on a parchment paper substrate that …

Development Of Non-Invasive In Vivo Ultrasound Imaging Techniques For Elastase-Induced Experimental Abdominal Aortic Aneurysms, Alexa A. Yrineo, Elizabeth A. Nunamaker, Hilary D. Schroeder, Amy E. Bogucki, Craig J. Goergen

The Summer Undergraduate Research Fellowship (SURF) Symposium

Abdominal aortic aneurysms (AAAs) are pathological dilations of the aorta which are associated with significant morbidity and mortality. The underlying mechanisms that cause this inflammatory disease are not fully understood and thus, are currently under investigation. In the hopes of preventing disease progression, rodent models that mimic the human condition have been developed to provide insight into the pathogenesis of AAAs. In this study, porcine pancreatic elastase (0.44 U; Sigma-Aldrich) was infused into the infrarenal aortas of male, Sprague Dawley rats to induce aneurysms. To perform the surgery, temporary ligatures were placed around proximal and distal sections of the abdominal …

Direct Quantitative Analysis Of Biomarkers Using Mass Spectrometry, Morgan N. Mcluckey, Zheng Ouyang

The Summer Undergraduate Research Fellowship (SURF) Symposium

Point-of-care (POC) diagnostics describes a step in the medical treatment process where drugs can be monitored in a patient’s body on-site and in a timely fashion. Mass spectrometry (MS) can provide a quick, efficient, and highly accurate method of analysis of patient biofluids and tissues. Developing methods to bring this diagnostic mechanism to hospitals and clinics has the potential to improve patient care through, for example, personalized medicine. Our goal was to develop a way to effectively introduce internal standard (IS), a necessary chemical for the analytical process, to low-volume biofluid samples. Additionally, the effective direct quantitation of biomarkers with …

Iron-Magnesium Alloy Bioabsorbable Blood Stent, Kaitlyn Jarry, L Stanciu

The Summer Undergraduate Research Fellowship (SURF) Symposium

Bioabsorbable materials are fairly new and proper alloys for implantation in the body have not yet been established. There are a few polymers that have showed promise, but they do not provide the proper mechanical support that metal does. These materials would be used to create devices such as blood stents and orthopedic screws. Investigation into the properties of different alloys can help to establish a material that can be used for implanted devices that are only needed for a limited amount of time. In order to investigate these alloys many different experiments will to be run to test the …

Characterization Of The Saturation Level Of Nucleosome Arrays And Plasmids By Mnase Digestion, Wenjie Liu, Nathan Nurse, Chongli Yuan

The Summer Undergraduate Research Fellowship (SURF) Symposium

Studying processes involving DNA such as DNA replication and transcription is best done in the context of chromatin because the structure of DNA influences the efficiency of such processes. Chromatin structure is derived from DNA wrapping around histone octamers with the histone octamer density termed saturation level. For in vitro studies on DNA replication and transcription, it is important to maintain a constant saturation level so that saturation level can be removed as a variable. Our goal is to characterize the saturation level of plasmids using the rate of MNase digestion. MNase digestions were first performed on reconstituted nucleosome arrays …

Ecog Correlates Of Visuomotor Transformation, Neural Plasticity, And Application To A Force-Based Brain Computer Interface, Jordan John Williams

All Theses and Dissertations (ETDs)

Electrocorticography: ECoG) has gained increased notoriety over the past decade as a possible recording modality for Brain-Computer Interface: BCI) applications that offers a balance of minimal invasiveness to the patient in addition to robust spectral information over time. More recently, the scale of ECoG devices has begun to shrink to the order of micrometer diameter contacts and millimeter spacings with the intent of extracting more independent signals for BCI control within less cortical real-estate. However, most control signals to date, whether within the field of ECoG or any of the more seasoned recording techniques, have translated their control signals to …

Data Workflow In Large Scale Simulations Of Blood Flow In Aneurysms, Paolo Di Achille, Jay D. Humphrey

Yale Day of Data

Aneurysms are responsibile for significant morbidity and mortality, and there is a need for an increased understanding of all the aspects of the natural history of these lesions. We are currently working to extend our analyses with the goal of creating models of aneurysmal progression that are able to predict rupture risk through the description of the evolving geometry, structure, properties, and loads.

Realization of patient specific models of the blood circulation necessitates a complex computationally and data intensive procedure that starts from the collection of medical images in a clinical setting and encompasses several stages of data processing on …

Cross-Linked Alginate Film Pore Size Determination Using Atomic Force Microscopy And Validation Using Diffusivity Determinations, Cheryl Simpliciano, Larissa Clark, Behrokh Asi, Nathan Chu, Maria Mercado, Steven Diaz, Michel Goedert, Maryam Mobed-Miremadi

Bioengineering

The deficit of organ donors has fueled the need for advances in tissue engineering and regenerative medicine. Microencapsulation in alginate immuno-isolation membranes has been used to treat many disabling metabolic disorders, namely, phenylketonuria, kidney failure and diabetes mellitus. Systematic nutrient flux determinations are hindered by the lack of experimental data on alginate-based membrane topography and the pore size thus preventing the full therapeutic potential of the bio-membranes to be reached. In this study, samples of cross-linked alginate membranes were subjected to the following analytical characterization: 1) pore size characterization using atomic force microscopy operated in contact mode to detect and …

Department Of Biological Systems Engineering Newsletter, October 2013

BSE Department Magazine

No abstract provided.

Slow Potentials Of The Sensorimotor Cortex During Rhythmic Movements Of The Ankle, Ryan J. Mckindles

Dissertations (1934 -)

The objective of this dissertation was to more fully understand the role of the human brain in the production of lower extremity rhythmic movements. Throughout the last century, evidence from animal models has demonstrated that spinal reflexes and networks alone are sufficient to propagate ambulation. However, observations after neural trauma, such as a spinal cord injury, demonstrate that humans require supraspinal drive to facilitate locomotion. To investigate the unique nature of lower extremity rhythmic movements, electroencephalography was used to record neural signals from the sensorimotor cortex during three cyclic ankle movement experiments. First, we characterized the differences in slow movement-related …

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 …

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 …

Formulation To Predict Lower Limb Muscle Forces During Gait, Gil Serrancolí, Jonathan P. Walter, Allison Kinney, A. Barjau, Benjamin J. Fregly, Josep M. Font-Llagunes

Mechanical and Aerospace Engineering Faculty Publications

The human body has more muscles than Degrees of Freedom (DoF), and that leads to indeterminacy in the muscle force calculation. This study proposes the formulation of an optimization problem to estimate the lower-limb muscle forces during a gait cycle of a patient wearing an instrumented knee prosthesis. The originality of that formulation consists of simulating muscle excitations in a physiological way while muscle parameters are calibrated. Two approaches have been considered. In Approach A, measured contact forces are applied to the model and all inverse dynamics loads are matched in order to get a physiological calibration of muscle parameters. …

Effect Of Tilt Sensor Versus Heel Loading On Neuroprosthesis Stimulation Reliability And Timing For Individuals Post-Stroke During Level And Non- Level Treadmill Walking, M. Barbara Silver-Thorn

Biomedical Engineering Faculty Research and Publications

Study background: Non-level walking may adversely affect stimulation of neuroprostheses as initial programming is performed during level walking. The objectives of this study were to assess stimulation reliability of tilt and heel sensor-based neuroprosthesis stimulation during level and non-level walking, examine stimulation initiation and termination timing during level and non-level walking, and determine whether heel or tilt sensor-based stimulation control is more robust for non-level ambulation. Methods: Eight post-stroke individuals with drop foot who were able to actively ambulate within the community were selected for participation. Each subject acclimated to the neuroprosthesis and walked on a treadmill randomly positioned in …

Characterization And Limitations Of Diffusion Tensor Imaging Metrics In The Cervical Spinal Cord In Neurologically Intact Subjects, Aditya Vedantam, Michael B. Jirjis, Brian D. Schmit, Marjorie C. Wang, John L. Ulmer, Shekar N. Kurpad

Biomedical Engineering Faculty Research and Publications

Purpose

To characterize diffusion tensor imaging (DTI) metrics across all levels of the cervical spinal cord (CSC) and to study the impact of age and signal quality on these metrics.

Materials and Methods

DTI metrics were calculated for gray matter (GM) and white matter (WM) funiculi throughout the CSC (C1–T1) in 25 healthy subjects (22-85 years old). Signal-to-noise ratios (SNRs) and mean DTI metrics were measured for the upper (C1-3), middle (C4-6) and lower (C7-T1) cervical segments. Age-related changes in DTI metrics were analyzed for the individual segment groups.

Results

Fractional anisotropy (FA), mean diffusivity (MD) and transverse apparent diffusion …

Dynamic Balance Control During Treadmill Walking In Chronic Stroke Survivors, Eric Richard Walker

Dissertations (1934 -)

Maintaining dynamic balance is an important component of walking function that is likely impaired in chronic stroke survivors, evidenced by an increased prevalence of falls. Dynamic balance control requires maintaining the center of mass (COM) within the base of support during movement. During walking, dynamic balance control is achieved largely by modifying foot placement to adjust the base of support. However, chronic stroke survivors have difficulty with both precision control of foot placement, as well as reduced control of COM movement. The objective of this dissertation was to characterize dynamic balance control strategies during walking in chronic stroke survivors. Additionally, …

Supraspinal Control Of Unilateral Locomotor Performance: An Fmri Study Using A Custom Pedaling Device, Brett Arand

Master's Theses (2009 -)

This study aimed to develop a novel unilateral pedaling device, validate its function, and use it in an fMRI study of bilateral vs. unilateral locomotor control. The new device is MRI compatible and allows for conventional coupled bilateral pedaling, along with decoupled unilateral pedaling. It was designed with an assistance mechanism to simulate the presence of the non-contributing leg while pedaling unilaterally. During coupled bilateral pedaling, the two legs work in unison: while one leg is extending in the downstroke, it provides support to lift the other leg back up as it is flexing in the upstroke. The device uses …

Quantification Of Local Hemodynamic Alterations Caused By Virtual Implantation Of Three Commercially-Available Stents For The Treatment Of Aortic Coarctation, Sung Kwon

Master's Theses (2009 -)

Patients with coarctation of the aorta (CoA) are prone to morbidity including atherosclerotic plaque that has been shown to correlate with altered wall shear stress (WSS) in the descending thoracic aorta (dAo). We created the first patient-specific computational fluid dynamics (CFD) model of a CoA patient treated by Palmaz stenting, and compared resulting WSS distributions to those from virtual implantation of the NumedCP and GenesisXD stents also commonly used for CoA. CFD models were created from magnetic resonance, fluoroscopy and blood pressure (BP) data. Simulations incorporated vessel deformation, downstream vascular resistance and compliance to match measured data and generate blood …