Engineering Commons^™

Site-Specific Deoxyribonucleic Acid Modifications For Use With Chemical Cages, John P. Casey Jr

Honors Capstones

No abstract provided.

The Effect Of Hydrostatic Pressure On Bladder Smooth Muscle Cell Function, Margaret Drumm

All Theses

Previous research has demonstrated that bladder smooth muscle cells (BSMC) respond to various forms of mechanical stimuli, including stretch and hydrostatic pressure, by increases of cell proliferation, activation of intracellular signaling pathways, and alteration of contractile and synthetic marker protein expression. These cellular/molecular level changes are all indicative of a BSMC phenotypic shift that can negatively impact the bladder function at the tissue and organ level. The objective of the present study is to test a hypothesis that bladder SMCs shift their phenotype from contractile to synthetic in response to elevated hydrostatic pressure. Rat bladder SMC cultures were exposed to …

A Pulsatile Bioreactor For Conditioning Tissue Engineered Heart Valves, Leslie Sierad

All Theses

Tissue engineered constructs with autologous adult stem cells capable of self-repair and growth are highly desired replacements for diseased heart valves. However, the current approaches have inadequate mechanical properties to withstand in vivo implantation. Therefore, our group hypothesized that an in vitro environment of physiological intra-cardiac pressures and flow will stimulate stem cells to differentiate and remodel valvular scaffold constructs before implantation.
The group developed a pneumatic-driven conditioning system (Aim I) consisting of a three-chambered heart valve bioreactor, a pressurized compliance tank, a reservoir tank, one-way valves, pressure-retaining valves, and pressure transducers. The system can be sterilized using conventional autoclaving …

Adsorption-Induced Changes In Enzyme Bioactivity Correlated With Adsorbed Protein Orientation And Conformation, Kenan Fears

All Dissertations

Systems using immobilized enzymes are attractive for a wide range of industrial and medical applications because they allow for fabrication of stable, reusable substrates with a highly specific functionality. The performance of these systems is greatly influenced by the orientation and conformation of the immobilized enzymes. To investigate these relationships, we have developed and applied methods to quantitatively assess the secondary structure of adsorbed enzyme layers on planar surfaces using circular dichroism (CD) spectropolarimetry and evaluate their bioactivity using colorimetric assays. When combined with knowledge of an enzyme's native structure, these methods provide a means to correlate changes in enzyme …

Development Of An In-Vitro Tissue Engineered Blood Vessel Mimic Using Human Large Vessel Cell Sources, Dimitri E. Delagrammaticas

Master's Theses

Tissue engineering is an emerging field that offers novel and unmatched potential medical therapies and treatments. While the vast aim of tissue engineering endeavors is to provide clinically implantable constructs, secondary applications have been developed to utilize tissue-engineered constructs for in-vitro evaluation of devices and therapies. Specifically, in-vitro blood vessel mimics (BVM) have been developed to create a bench-top blood vessel model using human cells that can be used to test and evaluate vascular disease treatments and intravascular devices. Previous BVM work has used fat derived human microvascular endothelial cells (EC) sodded on an ePTFE scaffold. To create a more …

Implementation Of Physiologic Flow Conditions In A Blood Vessel Mimic Bioreactor System For The Evaluation Of Intravascular Devices, Marc Cody Dawson

Master's Theses

The prevalence and devastating nature of cardiovascular diseases has led to many advancements in the therapies used to treat the millions of patients that suffer as a result of these conditions. As coronary artery disease (CAD) is the most common of these cardiovascular conditions, it is a major focus of research among the medical industry. Although lifestyle changes and drug therapies can treat early CAD, more advanced cases often require more definitive interventions. In conjunction with angioplasty, stenting of an occluded vessel has shown significant success in preventing restenosis. However, as with nearly every therapeutic process in the medical field, …

Vascular Injury After Whole Thoracic X-Ray Irradiation In The Rat, S. N. Ghosh, Q. Wu, M. Mäder, B. L. Fish, John E. Moulder, Elizabeth R. Jacobs, Meetha Medhora, Robert C. Molthen

Biomedical Engineering Faculty Research and Publications

Purpose

To study vascular injury after whole thoracic irradiation with single sublethal doses of X-rays in the rat and to develop markers that might predict the severity of injury.

Methods and Materials

Rats that received 5- or 10-Gy thorax-only irradiation and age-matched controls were studied at 3 days, 2 weeks, and 1, 2, 5, and 12 months. Several pulmonary vascular parameters were evaluated, including hemodynamics, vessel density, total lung angiotensin-converting enzyme activity, and right ventricular hypertrophy.

Results

By 1 month, the rats in the 10-Gy group had pulmonary vascular dropout, right ventricular hypertrophy, increased pulmonary vascular resistance, increased dry lung …

Magnetic Sensors For Biodetection, Pranjali Vineet Sneha Deshpande

UNLV Theses, Dissertations, Professional Papers, and Capstones

The objective of thesis is to design magnetic sensor for detection of nanoparticles. Recently integrating the standard laboratory techniques into integrated system on chip is growing attention. Recent development is to combine magnetic markers and magnetoresistive sensors together in magnetic chip. In this thesis two magnetoresistive sensors were studied and designed.

By applying magnetic fields, magnetic nanoparticles can be manipulated on-chip, which can be utilized to pull the molecules to specific binding sites or to test the binding strength and distinguish between specifically and non-specifically bound molecules

Magnetoresistive sensors are compatible with the semiconductor industry which provides electronic signal directly …

Investigation Of Magnetic Resonance Imaging And Spectroscopy For The Detection Of Breast Cancer, Robert Thomas Etnire

UNLV Theses, Dissertations, Professional Papers, and Capstones

Magnetic resonance imaging (MRI) of the breast offers an alternative to screening mammography which may benefit those women at high risk for breast cancer, women under the age of 40, and those with dense breast tissue. One concern with MRI is the number of high false positives. Coupling MRI with magnetic resonance spectroscopy(MRS) may lower the number of false positives, and thus improve the diagnostic capabilities of MRI for the clinician. MRS for breast imaging focuses on the total choline containing compounds in the spectra in the suspected breast lesion to analyze areas of concern. The results of the study …

Inducing A Normal Phenotype In Breast Epithelial Cells Using A Three-Dimensional Basement Membrane Extract Culture System: A Study On The Reversion Of Cancer, Ross H. Booth

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Experimentally, traditional developmental models and transgenic animals consistently underscore the importance of studying cell behavior in the correct tissue context. However, live animal experimentation is inherently complex, and systematic assessment of the effects of individual variables, such as cell shape and matrix compliance on cell behavior, is extremely difficult at best. Two-dimensional monolayer culture of key individual cell types has provided abundant, fundamental information on cell response, but cannot be used to show the normal phenotype of breast epithelial cells. Furthermore, their results often fail to translate into in vivo and clinical studies. It has been previously established that normal …

Structural And Functional Considerations In The Design Of Collagen-Based Electrospun Scaffolds, Chantal Ayres

Theses and Dissertations

Electrospinning can be used to selectively process a variety of natural and synthetic polymers into highly porous scaffolds composed of nano-to-micron diameter fibers. This process shows great potential as a gateway to the development of physiologically relevant tissue engineering scaffolds. In this study we examine the structural and functional considerations regarding electrospun scaffolds for dermal template applications using novel quantification techniques. In order to characterize scaffold structure, a technique utilizing the fast Fourier transform was developed to systematically quantify fiber alignment and evaluate how different electrospinning parameters impact the structure and material properties of an electrospun scaffold. Gelatin was suspended …

A Numerical Approach For Predicting The Impact Of Vascular Architecture On Blood Flow During Ischemic Repair, Stephanie Ann Wood, Shilpi Ghosh, Kevin Jones, Gabriel Gruionu, Trevor R. Cardinals

Biomedical Engineering

Abstract of conference presentation.

Functional Vasodilation Following Murine Chronic Hindlimb Ischemia, Matthew David Yocum, Trevor R. Cardinal

Biomedical Engineering

Abstract of conference presentation.

Impedance Spectroscopy Of Zebrafish Sperm, Robert Egnatchik

Honors Capstones

No abstract provided.

Fatigue Strength Of Common Tibial Intramedullary Nail Distal Locking Screws, Lanny V. Griffin, Robert M. Harris, Joseph J. Zubak

Biomedical Engineering

Premature failure of either the nail and/or locking screws with unstable fracture patterns may lead to angulation, shortening, malunion, and IM nail migration. Up to thirty percent of all unreamed nail locking screws can break after initial weight bearing is allowed at 8–10 weeks if union has not occurred. The primary problem this presents is hardware removal during revision surgery. The purposes of our study was to evaluate the relative fatigue resistance of distal locking screws and bolts from representative manufacturers of tibial IM nail systems, and develop a relative risk assessment of screws and materials used. Evaluations included quantitative …

Botulinum Toxin For Non-Surgical Lateral Release In Subjects With Patellofemoral Pain, Laura Maple

Theses and Dissertations

Previous studies for treating Patellofemoral Pain Syndrome (PFPS) are controversial regarding the effectiveness in alleviating anterior knee pain (AKP). The muscular imbalance between the vastus medialis oblique/vastus lateralis (VMO/VL) may be the underlying mechanical issue causing PFPS. It is hypothesized that Botox can decrease the force production capability of the lateral musculature mechanically similar to surgery. Strengthening the VMO while using Botox treatment can alleviating the muscular imbalance that occurs with subjects with PFPS. A double blind study, having all participants blinded and uninformed of the injection contents, was implemented to test this hypothesis testing three female subjects. Four knees …

Applied Electrokinetics For Tissue Engineering Applications, Stephanie R. Tully-Dartez

Doctoral Dissertations

Tissue engineering could provide an alternative source of transplant tissue regardless of donor supply and with reduced risk of immune rejection. Engineered tissue requires three critical components for successful development: the cells, growth factors, and the scaffold on which they will initially grow. The scaffold acts as a temporary extracellular matrix (ECM) allowing cell attachment and acclimation to the environment prior to synthesis and construction of the cell's native ECM. Prior to cell seeding, the scaffold must be characterized to determine whether or not the pore geometry is conducive to cell implantation. Electrochemical impedance spectroscopy (EIS) provides a unique and …

Nano-Formulation And Controlled Delivery Of Low Solubility Anticancer Drugs, Anshul Agarwal

Doctoral Dissertations

Optimal drug delivery and reduction of systemic adverse effects have been age old problems in chemotherapeutics in all types of human cancer. During chemotherapy, using water insoluble drugs like paclitaxel and tamoxifen, it has been realized that better formulations are needed for more specific and controlled drug delivery of these agents. In a novel approach to form high content stable nanocolloids of these drugs with controllable release rate, a sonicated layer-by-layer (LbL) polyelectrolyte coating technology is suggested. The desired features of pharmaceutical carriers for intravenous administration include their small size and biodegradability, good loading capacity for a given drug, high …

A Real-Time, 3-D Musculoskeletal Model For Dynamic Simulation Of Arm Movements, Edward K. Chadwick, Dimitra Blana, Antonie J. Van Den Bogert, Robert F. Kirsch

Mechanical Engineering Faculty Publications

Neuroprostheses can be used to restore movement of the upper limb in individuals with high-level spinal cord injury. Development and evaluation of command and control schemes for such devices typically require real-time, ldquopatient-in-the-looprdquo experimentation. A real-time, 3-D, musculoskeletal model of the upper limb has been developed for use in a simulation environment to allow such testing to be carried out noninvasively. The model provides real-time feedback of human arm dynamics that can be displayed to the user in a virtual reality environment. The model has a 3-DOF glenohumeral joint as well as elbow flexion/extension and pronation/supination and contains 22 muscles …

Gold Nanorod-Mediated Photothermolysis Induces Apoptosis Of Macrophages Via Damage Of Mitochondria, Ling Tong, Ji-Xin Cheng

Other Nanotechnology Publications

Aims: Induction of apoptosis or necrosis in activated macrophages by gold nanorod-mediated photothermolysis is demonstrated and the mechanisms underlying the processes are investigated. Materials & methods: Gold nanorods were functionalized with cysteine-octaarginine peptides (R8-NRs). Uptake of R8-NRs by activated macrophages was monitored by two-photon luminescence imaging. The laser irradiation conditions were controlled to induce apoptosis or necrosis to R8-NR-internalized macrophages. Mitochondrial damage and reactive oxygen species overproduction during photothermolysis was investigated by confocal fluorescence microscopy and transmission-electron microscopy. Results: Activated macrophages efficiently uptake R8-NRs both in vitro and in live animals. Laser irradiation of internalized nanorods with controlled power density …

Analysis Of Electroencephalogram Signals For The Identification Of Mental Tasks, My Thy Thi Tran

Electrical & Computer Engineering Theses & Dissertations

Electroencephalogram (EEG) signals can be used for implicit communication such as to control robots or medical equipment by brain activity or to detect an individual's intentions of committing premeditated crimes. An EEG based brain-computer interface allows paralyzed patients to express their thoughts. However, biological and technical artifacts heavily interfered with EEG signals due to blinking of the eyes, muscle activities and line noise. Sometimes the noise interference due to signal artifacts becomes more prominent than the information content. This thesis investigates novel feature extraction methodologies in EEG signals to represent different thought processes and employs neural network-based pattern classification techniques …

Ankle Load Modulates Hip Kinetics And Emg During Human Locomotion, Keith E. Gordon, Ming Wu, Jennifer H. Kahn, Yasin Y. Dhaher, Brian D. Schmit

Biomedical Engineering Faculty Research and Publications

The purpose of this research was to examine the role of isolated ankle-foot load in regulating locomotor patterns in humans with and without spinal cord injury (SCI). We used a powered ankle-foot orthosis to unilaterally load the ankle and foot during robotically assisted airstepping. The load perturbation consisted of an applied dorsiflexion torque designed to stimulate physiological load sensors originating from the ankle plantar flexor muscles and pressure receptors on the sole of the foot. We hypothesized that 1) the response to load would be phase specific with enhanced ipsilateral extensor muscle activity and joint torque occurring when unilateral …

The In Vitro Characterization Of Chitosan-Plga Nanoparticle/Plasmid Dna Complexes, Hali Bordelon

Honors Capstones

No abstract provided.

In Vitro Ovarian Tumor Growth And Treatment Response Dynamics Visualized With Time-Lapse Oct Imaging, Conor L. Evans, Imran Rizvi, Tayyaba Hasan, Johannes F. De Boer

Dartmouth Scholarship

In vitro three-dimensional models for metastatic ovarian cancer have been useful for recapitulating the human disease. These spheroidal tumor cultures, however, can grow in excess of 1 mm in diameter, which are difficult to visualize without suitable imaging technology.Optical coherence tomography (OCT) is an ideal live imaging method for non-perturbatively visualizing these complex systems. OCT enabled detailed observations of the model at both nodular and cellular levels, revealing growth dynamics not previously observed. The development of a time-lapse OCT system, capable of automated, multidimensional acquisition, further provided insights into the growth and chemotherapeutic response of ovarian cancer.

The Rom / Uwo Mummy Project: A Microcosm Of Progress In Mummy Research, Andrew J. Nelson, R. Chhem, I. A. Cunningham, S. N. Friedman, G. Garvin, G. Gibson, P. V. Granton, David W. Holdsworth, S. Holowka, F. Longstaffe, V. Lywood, N. Nguyen, R. Shaw, M. Trumpour, Andrew D. Wade, C. D. White

Anthropology Presentations

The beginnings of the Royal Ontario Museum can be traced back to the excavations and collections of Charles Trick Currelly, a staff member of the Egyptian Exploration Fund in the early 1900s. Currelly excavated with Sir Flinders Petrie at Abydos and with Edouard Naville at Deir el Bahari. With the assistance of Robert Mond and others, Currelly amassed a rich and diverse collection that became the basis for the ROM, which opened its doors in 1914. Part of that collection included several Egyptian mummies (Currelly 1971) .

The Egyptologicalholdings at the ROM include eight mummies: one dating to the Predynastic …

Biofilm Inhibitory Coatings Formulated From Glass Polyalkenoate Cement Chemistry: An Evaluation Of Their Adhesive Nature, A. Coughlan, D. Boyd, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

Researchers evaluated the adhesive nature of the biofilm inhibitory coatings formulated from glass polyalkenoate cement (GPC) chemistry with the aim to establish the novel testing modality by modifying the conventional T-peel tests. Special consideration was given to determine the resistance of a bonded assembly of two adherents having at least one adherent flexible to quantify the bond between tape and a surgical metal substrate bonded by a luting GPC. The delaminated tape surface was examined by scanning electron microscopy (SEM) with an accelerating voltage of 20 K V to determine whether failure of the bond was adhesive of cohesive in …

The Relationships Between Muscle, External, Internal And Joint Mechanical Work During Normal Walking, Kotaro Sasaki, Richard R. Neptune, Steven A. Kautz

Mechanical and Biomedical Engineering Faculty Publications and Presentations

Muscle mechanical work is an important biomechanical quantity in human movement analyses and has been estimated using different quantities including external, internal and joint work. The goal of this study was to investigate the relationships between these traditionally used estimates of mechanical work in human walking and to assess whether they can be used as accurate estimates of musculotendon and/or muscle fiber work. A muscle-actuated forward dynamics walking simulation was generated to quantify each of the mechanical work measures. Total joint work (i.e. the time integral of absolute joint power over a full gait cycle) was found to underestimate total …

Assessing The Prediction Potential Of An In Silico Computer Model Of Intracranial Pressure Dynamics, Wayne Wakeland, Rachel Agbeko, Kevin Vinecore, Mark Peters, Brahm Goldstein

Complex Systems Faculty Publications and Presentations

Objective: Traumatic brain injury (TBI) frequently results in poor outcome, suggesting that new approaches are needed. We hypothesized that a patient-specific in silico computer model of intracranial pressure (ICP) dynamics may predict the ICP response to therapy.

Design: In silico model analysis of prospectively collected data.

Setting: Twenty-three and 16-bed pediatric intensive care units in two tertiary care academic hospitals.

Patients: Nine subjects with severe TBI undergoing ICP monitoring (7 M/2 F, age range 3-17 years).

Interventions: Random changes in head-of-bed (HOB) (0[degrees], 10[degrees], 20[degrees], 30[degrees], 40[degrees]) elevation and respiratory rate (to achieve a [DELTA]ETco2 = +/-3-4 mm Hg) were …

Short-Term Osteoclastic Activity Induced By Locally High Concentrations Of Recombinant Human Bone Morphogenetic Protein–2 In A Cancellous Bone Environment, Jeffrey M. Toth, Scott D. Boden, J. Kenneth Burkus, Jeffrey Badura, Steve M. Peckham, William Mckay

Biomedical Engineering Faculty Research and Publications

Study Design. An experimental study investigating osteoclastic activity induced by rhBMP-2 in sheep.

Objective. To examine the effects of increasing local rhBMP-2 concentration on osteoclastic response and peri-implant bone resorption.

Summary of Background Data. Level I clinical studies have established the safe and effective volume and concentration of rhBMP-2 delivered on an absorbable collagen sponge. However, peri-implant bone resorption appearing as decreased mineral density has been observed radiographically in rare instances after implantation of rhBMP-2 on an absorbable collagen sponge (rhBMP-2/ACS).

Methods. Bilateral corticocancellous defects were created in the distal femora of 30 adult sheep. Combinations of rhBMP-2/ACS implant volume …

Synthesis And Characterization Of Hazelnut Oil-Based Biodiesel, Yixiang Xu, Milford Hanna

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The demand for diesel fuel far exceeds the current and future biodiesel production capabilities of the vegetable oil and animal fat industries. New oilseed crops that do not compete with traditional food crop are needed to meet existing energy demands. Hybrid hazelnut oil is just such an attractive raw material for production of biodiesel. Hazelnut oil was extracted from hybrid hazelnuts and the crude oil was refined. Hazelnut oil-based biodiesel was prepared via the transesterification of the refined hazelnut oil with excess methanol using an alkaline catalyst. The effects of reaction temperature, time and catalyst concentration on the yield of …