Engineering Commons^™

Nitric Oxide Releasing Polymers For Vascular Graft Applications, Ifeanyi U. Onyejekwe

Biomedical and Chemical Engineering - Dissertations

Nitric oxide [NO] is an endogenous gas involved in a multitude of physiological functions, ranging from vasodilatation, inflammatory response to inhibition of platelet aggregation. Significant interest exists for therapeutic application of exogenous NO, particularly for the improvement of foreign-body responses of biomaterials. One challenge amongst several others that must be taken into consideration is NO's short half-life, ranging from 2-3 s, in physiological systems. Researchers have worked on synthesizing materials, formally referred to as NO donors/NONOates capable of preserving NO and spontaneous gas release upon contact with blood under physiological conditions. Two groups of these commercially available NO donors known …

The Role Of Fluorescence And Human Factors In Quantitative Transdermal Blood And Tissue Analysis Using Nir Raman Spectroscopy, Bin Deng

Biomedical and Chemical Engineering - Dissertations

This research is part of an ongoing project aimed at the application of combined near infrared (NIR) Raman and fluorescence spectroscopy to noninvasive in vivo blood analysis including but not limited to glucose monitoring. Coping with practicalities of human factors and exploring ways to obtain and use knowledge gained about autofluorescence to improve algorithms for blood and tissue analysis are the general goals of this research. Firstly, the study investigated the various sources of human factors pertinent to our concerns, such as fingerprints, turgor, skin hydration and pigmentation. We then introduced specialized in vivo apparatus including means for precise and …

Auto-Fluorescence Lifetime And Light Reflectance Spectroscopy For Breast Cancer Diagnosis: Potential Tools For Intraoperative Margin Detection, Vikrant Sharma, Shivaranjani Shivalingaiah, Yan Peng, David Euhus, Zygmunt Gryczynski, Hanli Liu

Bioengineering Faculty Publications - Archive

This study investigates the use of two spectroscopic techniques, auto-fluorescence lifetime measurement (AFLM) and light reflectance spectroscopy (LRS), for detecting invasive ductal carcinoma (IDC) in human ex vivo breast specimens. AFLM used excitation at 447 nm with multiple emission wavelengths (532, 562, 632, and 644 nm), at which autofluorescence lifetimes and their weight factors were analyzed using a double exponent model. LRS measured reflectance spectra in the range of 500-840 nm and analyzed the spectral slopes empirically at several distinct spectral regions. Our preliminary results based on 93 measured locations (i.e., 34 IDC, 31 benign fibrous, 28 adipose) from 6 …

Effects Of Physiological Dynamic Compression Loading On Gold Nanoparticle Permeation Of Articular Cartilage, Britton Mccaskill

All Theses

Articular cartilage is essential part of the human body that aids in support and locomotion. It has unique biochemical and biomechanical properties that allow it to act as a shock absorber to disperse and distribute loading of the joints. However, it has a limited capacity to repair itself because it is not vascularized and must receive its nutrients from the surrounding synovial fluid. Articular cartilage damage can lead to many pathological conditions, including osteoarthritis. Currently, there are many surgical treatment methods that repair some of the damage if it is localized, but for widespread degradation seen in osteoarthritis, there are …

Gallium Containing Glass Polyalkenoate Anti-Cancerous Bone Cements: Glass Characterization And Physical Properties, A. W. Wren, A. Coughlan, L. Placek, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

A gallium (Ga) glass series (0.48SiO₂-0.40ZnO-0.12CaO, with 0.08 mol% substitution for ZnO) was developed to formulate a Ga-containing Glass Polyalkenoate Cement (GPC) series. Network connectivity (NC) and X-ray Photoelectron Spectroscopy (XPS) was employed to investigate the role of Ga³⁺ in the glass, where it is assumed to act as a network modifier. Ga-GPC series was formulated with E9 and E11 polyacrylic acid (PAA) at 50, 55 and 60 wt% additions. E11 working times (T_w) ranged from 68 to 96 s (Lcon.) and 106 s for the Ga-GPCs (LGa-1 and LGa-2). Setting times (T_s) …

Experimental Composite Guidance Conduits For Peripheral Nerve Repair: An Evaluation Of Ion Release, X. F. Zhang, A. Coughlan, H. O'Shea, Mark R. Towler, S. Kehoe, D. Boyd

Chemical and Biochemical Engineering Faculty Research & Creative Works

Poly (lactide-co-glycolide) (PLGA) - Pluronic F127 - glass composites have demonstrated excellent potential, from the perspective of controlled mechanical properties and cytocompatibility, for peripheral nerve regeneration. In addition to controlling the mechanical properties and cytotoxicity for such composite devices, the glass component may mediate specific responses upon implantation via degradation in the physiological environment and release of constituent elements. However, research focused on quantifying the release levels of such therapeutic ions from these experimental medical devices has been limited. To redress the balance, this paper explores the ion release profiles for Si⁴⁺, Ca²⁺, Na⁺, …

A Novel Haptic Simulator For Evaluating And Training Salient Force-Based Skills For Laparoscopic Surgery, Ravikiran Singapogu

All Dissertations

Laparoscopic surgery has evolved from an 'alternative' surgical technique to currently being considered as a mainstream surgical technique. However, learning this complex technique holds unique challenges to novice surgeons due to their 'distance' from the surgical site. One of the main challenges in acquiring laparoscopic skills is the acquisition of force-based or haptic skills. The neglect of popular training methods (e.g., the Fundamentals of Laparoscopic Surgery, i.e. FLS, curriculum) in addressing this aspect of skills training has led many medical skills professionals to research new, efficient methods for haptic skills training.
The overarching goal of this research was to demonstrate …

Ultrastable Synergistic Tetravalent Rna Nanoparticles For Targeting To Cancers, Farzin Haque, Dan Shu, Yi Shu, Luda S. Shlyakhtenko, Piotr G. Rychahou, B. Mark Evers, Peixuan Guo

Pharmaceutical Sciences Faculty Publications

One of the advantages of nanotechnology is the feasibility to construct therapeutic particles carrying multiple therapeutics with defined structure and stoichiometry. The field of RNA nanotechnology is emerging. However, controlled assembly of stable RNA nanoparticles with multiple functionalities which retain their original role is challenging due to refolding after fusion. Herein, we report the construction of thermodynamically stable X-shaped RNA nanoparticles to carry four therapeutic RNA motifs by self-assembly of reengineered small RNA fragments. We proved that each arm of the four helices in the X-motif can harbor one siRNA, ribozyme, or aptamer without affecting the folding of the central …

Upper Extremity Biomechanical Model For Evaluation Of Pediatric Joint Demands During Wheelchair Mobility, Alyssa J. Paul, Brooke A. Slavens, Adam Graf, Joseph Krzak, Lawrence Vogel, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Current methods for evaluating upper extremity (UE) dynamics during pediatric wheelchair use are limited. We propose a new model to characterize UE joint kinematics and kinetics during pediatric wheelchair mobility. The bilateral model is comprised of the thorax, clavicle, scapula, upper arm, forearm, and hand segments. The modeled joints include: sternoclavicular, acromioclavicular, glenohumeral, elbow and wrist. The model is complete and is currently undergoing pilot studies for clinical application. Results may provide considerable quantitative insight into pediatric UE joint dynamics to improve wheelchair prescription, training and long term care of children with orthopaedic disabilities.

Storage And Loss Moduli Of Bone In Osteogenesis Imperfecta (Oi), Carolyne Albert, John Jameson, Jeffrey Toth, Peter A. Smith, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Oral Delivery Of Peptide Drugs For Mitigation Of Crohn's Disease, Paul Blichmann

All Theses

Protein drugs are typically administered intravenously, but this practice has clear disadvantages such as widespread circulation and swift clearance from the body. Orally delivered protein drugs are not yet available but potentially offer improved distribution, retention, and activity by use of protective matrices and cell-specific targeting. Much work has been done on delayed release formulations for the upper intestine, but there has not been overwhelming evidence of protection of peptides from gastric conditions. In many instances the large intestine may be a better release target due to lower proteolytic activity. Afflictions of the colon such as Inflammatory Bowel Disease and …

The Biomechanical Role Of Scaffolds In Augmented Rotator Cuff Tendon Repairs, Amit Aurora, Jesse A. Mccarron, Antonie J. Van Den Bogert, Jorge E. Gatica, Joseph P. Iannotti, Kathleen A. Derwin

Mechanical Engineering Faculty Publications

Background

Scaffolds continue to be developed and used for rotator cuff repair augmentation; however, the appropriate scaffold material properties and/or surgical application techniques for achieving optimal biomechanical performance remains unknown. The objectives of the study were to simulate a previously validated spring-network model for clinically relevant scenarios to predict: (1) the manner in which changes to components of the repair influence the biomechanical performance of the repair and (2) the percent load carried by the scaffold augmentation component.

Materials and methods

The models were parametrically varied to simulate clinically relevant scenarios, namely, changes in tendon quality, altered surgical technique(s), and …

Analysis Of The Effect Of Feeding Regimen On Gh/Igf Axis In Channel Catfish (Ictalurus Punctatus), Samantha Puckett

Biological and Agricultural Engineering Undergraduate Honors Theses

Channel catfish (Ictalurus punctatus) are the most widely farmed aquatic animal in the United States. Assessing the effect of feeding regimens on their overall growth requires grow-out trials and a subsequent inefficient use of time and money. The growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis regulates growth based upon environmental factors such as feed intake in many teleost fish species. In order to increase the efficiency of aquaculture, the components of the GH/IGF-1 axis might be used as endocrine biomarkers to evaluate instantaneous growth rate. The goal of this study was to better understand the effects of feeding regimen on …

A Novel Method For Determining Acetabular Orientation, Sean Higgins

Theses and Dissertations

Enhanced knowledge of the acetabulum is of paramount importance in the diagnostic, planning, and execution stages of procedures and treatments targeting the hip joint. The convoluted and highly variable morphology of the structures comprising the bony pelvis make ascertaining measures of the acetabulum challenging. Furthermore, current methods for determining acetabular orientation assume symmetry between the separate halves of the pelvis by utilizing a coordinate system based on bilateral landmarks. The purpose of this study was to determine the three-dimensional orientation of the entire acetabulum. For this research, an improved programmatic method was developed for determining acetabular orientation using three-dimensional data. …

Changes In In Vivo Knee Contact Forces Through Gait Modification, Allison Kinney, Thor F. Besier, Amy Slider, Scott L. Delp, Darryl D. D'Lima, Benjamin J. Fregly

Mechanical and Aerospace Engineering Faculty Publications

Gait modification represents a non-invasive method for reducing knee joint loading in patients with knee osteoarthritis. Previous studies have shown that a variety of gait modifications are effective in reducing the external knee adduction moment. The external knee adduction moment is often used as a surrogate measure of medial compartment force. However, a recent study showed that reductions in the external knee adduction moment do not guarantee reductions in medial compartment loads. Therefore, direct measurement of changes in knee contact force is important for determining the effectiveness of gait modifications. A previous study found that medial thrust gait and walking …

Two-Dimensional Blood Flow Velocity Estimation Using Ultrasound Speckle Pattern Dependence On Scan Direction And Velocity, Tiantian Xu

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Cardiovascular disease is the leading cause death in the United States. Although emergency surgery and medicine can be used for cardiovascular disease treatment, the survivors will suffer for it afterwards. Ultrasound blood flow measurement provides a noninvasive way for cardiovascular diseases diagnosis. In this dissertation, three algorithms for blood flow velocity measurements were investigated and optimized. Feature tracking has been previously proposed for vector velocity measurement. In Chapter 3, the optimal amplitude and time thresholds for feature extraction were investigated to minimize flow estimate variance while providing sufficient spatial and temporal coverage of flow area. A new method of lateral …

Measurement Of The Oxidation State Of Mitochondrial Cytochrome C From The Neocortex Of The Mammalian Brain, Y. Sakata, M. Abajian, M. O. Ripple, R. Springett

Dartmouth Scholarship

Diffuse optical remission spectra from the mammalian neocortex at visible wavelengths contain spectral features originating from the mitochondria. A new algorithm is presented, based on analytically relating the first differential of the attenuation spectrum to the first differential of the chromophore spectra, that can separate and calculate the oxidation state of cytochrome c as well as the absolute concentration and saturation of hemoglobin. The algorithm is validated in phantoms and then tested on the neocortex of the rat during an anoxic challenge. Implementation of the algorithm will provide detailed information of mitochondrial oxygenation and mitochondrial function in physiological studies of …

Stabilization Of Extracellular Matrix Components In Bioprosthetic Heart Valves Using Neomycin And Pentagalloyl Glucose Enhanced Crosslinking, Daniel Tripi

All Theses

Bioprosthetic heart valves (BHVs) fail within 12-15 years of implantation due to limited durability. This limits their application to elderly population. Younger patients with contraindications for long-term anticoagulant therapy necessary for mechanical heart valves may also receive BHVs. Investigation into improving valve durability can lead to longer implant life, increased quality of life for patients receiving BHVs, and a broadened patient demographic.
Current BHVs are chemically treated with glutaraldehyde (GLUT) to stabilize collagen via chemical crosslinking and to reduce tissue antigenicity. GLUT fails to adequately stabilize elastin and glycosaminoglycans (GAGs), essential extracellular matrix components for valve function and durability. Degradation …

The Formulation Of A Bone Targeted Drug Delivery System Of Poly(Glycolic Acid)-Poly(Ethylene Glycol) Coated Hydroxyapatite Nanoparticles For The Delivery Of Statins, Erika Jelen

All Theses

Bone is a form of mineralized connective tissue that provides strength and rigidity to the skeleton. The two primary components within bone tissue are an organic extracellular matrix, containing type I collagen, and an inorganic mineral component composed mainly of calcium phosphate hydroxyapatite crystals. Over time the microarchitecture of bone can break down due to a variety of different factors, mainly the onset of osteoporosis in post-menopausal women, Paget's disease, and the experience of a loss of gravity during space flight. Currently there are about ten million people in the United States alone suffering from osteoporosis.
The prevention of further …

Investigating The Role Of Mechanosensitive Ion Channels In Urothelial Cell Pressure Mechanotransduction, Shawn Olsen

All Dissertations

Overactive bladder (OAB) is a bladder disorder that is characterized by bladder storage symptoms of urgency with or without urge incontinence, frequency, nocturia, and, as of 2003, affected approximately 16.5% of adults in the United States with an annual treatment cost of over $65 billion. While therapies are available to mitigate the symptoms of OAB, there are no treatments for the cause of OAB, due to the lack of understanding of the etiology of the disorder. Recent research has provided evidence that the bladder urothelium is not just a passive barrier, but is also sensitive to various chemical and mechanical …

Understanding The In Vivo Uptake Kinetics Of A Phosphatidylethanolamine-Binding Agent 99mTc-Duramycin, Said H. Audi, Zhixin Li, Joseph Capacete, Yu Liu, Wei Fang, Laura G. Shu, Ming Zhao

Biomedical Engineering Faculty Research and Publications

Introduction

^99mTc-Duramycin is a peptide-based molecular probe that binds specifically to phosphatidylethanolamine (PE). The goal was to characterize the kinetics of molecular interactions between ^99mTc-Duramycin and the target tissue.

Methods

High level of accessible PE is induced in cardiac tissues by myocardial ischemia (30 min) and reperfusion (120 min) in Sprague–Dawley rats. Target binding and biodistribution of ^99mTc-duramycin were captured using SPECT/CT. To quantify the binding kinetics, the presence of radioactivity in ischemic versus normal cardiac tissues was measured by gamma counting at 3, 10, 20, 60 and 180 min after injection. A partially inactivated form of …

The Effect Of A Navigational Aid On Training Of A Minimally Invasive Surgery Camera Task, Ketan Vidwans

Theses and Dissertations

Minimally Invasive Surgery (MIS) differs from Open Surgery as surgeons view the surgical site indirectly on a monitor. The view shown is typically from an angled endoscope off to one side of the surgery (i.e., uncollocated with the view of the hands). This makes camera navigation a challenging ability to learn. MIS thus requires longer training periods, more practice and mental effort to achieve proficiency. Current training setups and Operating Room (OR) environments lack appropriate real-time visual cues for navigation and other perception related information that could help with learning and performance in the OR. The purpose of this research …

Dynamics Of Depression Storage During Sprinkler Irrigation And Precipitation Events, Michael B. Mckinney

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Surface depression storage (D_s) is the volume of precipitation excess which is stored by surface microrelief features of soils. The volume of water stored in surface depressions when precipitation rate exceeds infiltration rate reduces the amount of runoff generated. Because Ds is dependent on soil microrelief, land slope, and crop residue, tillage and management practices can have a considerable impact on the magnitude of this value.

When modeling irrigation systems and surface hydrology, depression storage is often treated as a static abstraction, meaning that maximum storage volume must be filled before runoff occurs. However, several researchers have documented …

Evaluation Of A Novel Myoelectric Training Device, Ryan Clingman

Theses and Dissertations

While research shows that a patient’s success in using a myoelectric prosthetic arm is dependent on receiving effective training, current methods of training are not designed to effectively hold attention long enough for optimal training. This study focused on evaluating a novel myoelectric training device, consisting of a toy car controlled by EMG signals from the arm. Subjects’ performance with the trainer was evaluated to determine its ability to provide experience with EMG controls. Eight healthy adult subjects were taken through typical initial stages of myoelectric training, then asked to drive the car through a slalom course while the time, …

Life History Switch Point Plasticy In Response To Pond Drying Alyers Metamorph Allometry And Jumping Performance, Julie Charbonnier

Theses and Dissertations

Animals with complex life cycles can cope with environmental uncertainty by altering life history switch points through developmental plasticity. Pond drying is an important factor which may alter life history switch points in aquatic organisms. Many amphibians can plastically respond to changes in pond drying by emerging earlier, but few studies have examined the post-metamorphic consequences for performance. To investigate the potential carry-over effects of plasticity to pond drying, we studied the túngara frog, Physalaemus pustulosus, a tropical anuran that breeds in highly ephemeral habitats. We conducted a field study with three different water depth treatments in 60 L mesocosms …

Design, Analysis And Testing Of Haptic Feedback System For Laparoscopic Graspers In In Vivo Surgical Robots, Nikhil Salvi

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

Laparo-Endoscopic Single Site (LESS) Robotics Surgery is an advanced technology in the field of Minimally Invasive Surgery (MIS). The LESS surgical robots significantly improve the surgeon’s accuracy, dexterity and visualization, and reduce the invasiveness of surgical procedure results in faster recovery time and improved cosmetic results. In a standard robotic endosurgery, the palpation of tissues is performed by laparoscopic graspers located at the end effectors. The master-slave configuration in robotic surgery leads in remote access to the operation site. Therefore, surgeon’s ability to perceive valuable sensory information is severely diminished. Sensory information such as haptics, which is essential for safe …

Integrated Analysis Of Hydrothermal Flow Through Pretreatment, Veronique Archambault-Leger, Xiongjun Shao, Lee R. Lynd

Dartmouth Scholarship

Background:

The impact of hydrothermal flowthrough (FT) pretreatment severity on pretreatment and solubilization performance metrics was evaluated for three milled feedstocks (corn stover, bagasse, and poplar) and two conversion systems (simultaneous saccharification and fermentation using yeast and fungal cellulase, and fermentation by Clostridium thermocellum).

Results:

Compared to batch pretreatment, FT pretreatment consistently resulted in higher XMG recovery, higher removal of non-carbohydrate carbon and higher glucan solubilization by simultaneous saccharification and fermentation (SSF). XMG recovery was above 90% for FT pretreatment below 4.1 severity but decreased at higher severities, particularly for bagasse. Removal of non-carbohydrate carbon during FT pretreatment increased …

Complex Geometries For Particle Image Velocimetry (Piv) Testing, Elaine T. Maestas, Ryan Wicker, David Espalin, Francisco R. Medina

COURI Symposium Abstracts, Summer 2012

Clear, physical models or phantoms are needed for particle image velocimetry (PIV) to accurately record fluid velocities within complex geometries including anatomical structures. Based on Karina Arcaute’s work on “Complex Silicon Cardiovascular Models Manufactured Using a Dip-Spin Coating Technique”, a box casting technique was developed to provide the most effective phantom for testing. The phantom is required to be free of visual obstructions, thus allowing a CCD camera to capture accurate velocity readings. In this study, complex parts were made of a water-soluble material and sanded until all ridges were removed. The model was created using a fused deposition modeling …

Characterization Of Printed Skin Equivalents, Mayela R, Aldaz Cervantes, Maria Yanez, Thomas Boland

COURI Symposium Abstracts, Summer 2012

Severe burns, ulcerations, and cuts are some of the reasons people need bioengineered skin as a treatment for full-thickness wounds. When patients run out of donor sites in their own body, using the patient’s skin as a graft is no longer an option, and tissue-engineered constructs are the only possible replacement for damaged skin. The goal of this research is to develop a hydrogel-based skin graft that will be able to function as a skin replacement in full-thickness wounds while minimizing the possibility of rejection, being cost-effective, and possessing a longer shelf-life than the grafts currently in the market. Endothelial …

Development Of A Vaccine Printer For Helicobacter Pylori, Gabriela Enriquez, Julio E. Rincon, Thomas Boland

COURI Symposium Abstracts, Summer 2012

Helicobacter pylori is present in approximately half of the world’s population, of which approximately 2% develop a type of gastric cancer. This cancer is often discovered when being in an advanced stage due to its lack of symptoms. Unfortunately, a vaccine hasn’t been successfully developed against the bacterium. Therefore, the aim of this research is to develop the functional prototype of a DNA vaccine printer. Its parts were designed in the program NX. 6.0 and built out of ABS plastic using printing technology at the University of Texas at El Paso. After being assembled, the printer will be programmed and …