Biomedical Engineering and Bioengineering Commons^™

The Effect Of Cone Opsin Mutations On Retinal Structure And The Integrity Of The Photoreceptor Mosaic, Joseph Carroll, Alfredo Dubra, Jessica C. Gardner, Liliana Mizrahi-Meissonnier, Robert F. Cooper, Adam M. Dubis, Rick Nordgren, Mohamed Genead, Thomas B. Connor Jr., Kimberly E. Stepien, Dror Sharon, David M. Hunt, Eyal Banin, Alison J. Hardcastle, Anthony T. Moore, David R. Williams, Gerald Fishman, Jay Neitz, Maureen Neitz, Michel Michaelides

Biomedical Engineering Faculty Research and Publications

Purpose.

To evaluate retinal structure and photoreceptor mosaic integrity in subjects with OPN1LW and OPN1MW mutations.

Methods.

Eleven subjects were recruited, eight of whom have been previously described. Cone and rod density was measured using images of the photoreceptor mosaic obtained from an adaptive optics scanning light ophthalmoscope (AOSLO). Total retinal thickness, inner retinal thickness, and outer nuclear layer plus Henle fiber layer (ONL+HFL) thickness were measured using cross-sectional spectral-domain optical coherence tomography (SD-OCT) images. Molecular genetic analyses were performed to characterize the OPN1LW/OPN1MW gene array.

Results.

While disruptions in retinal lamination and cone mosaic structure were observed …

Assessing Retinal Structure In Complete Congenital Stationary Night Blindness And Oguchi Disease, Pooja Godara, Robert F. Cooper, Panagiotis I. Sergouniotis, Melissa A. Diederichs, Megan R. Streb, Mohamed Genead, J. Jason Mcanany, Andrew R. Webster, Anthony T. Moore, Adam M. Dubis, Maureen Neitz, Alfredo Dubra, Edwin M. Stone, Gerald A. Fishman, Dennis P. Han, Michel Michaelides, Joseph Carroll

Biomedical Engineering Faculty Research and Publications

Purpose

To examine retinal structure and changes in photoreceptor intensity after dark adaptation in patients with complete congenital stationary night blindness and Oguchi disease.

Design

Prospective, observational case series.

Methods

We recruited 3 patients with complete congenital stationary night blindness caused by mutations in GRM6, 2 brothers with Oguchi disease caused by mutations in GRK1, and 1 normal control. Retinal thickness was measured from optical coherence tomography images. Integrity of the rod and cone mosaic was assessed using adaptive optics scanning light ophthalmoscopy. We imaged 5 of the patients after a period of dark adaptation and examined layer …

Preliminary Investigation Of Residual Limb Plantarflexion And Dorsiflexion Muscle Activity During Treadmill Walking For Trans-Tibial Amputees, M. Barbara Silver-Thorn, Thomas Current, Benjamin Kuhse

Biomedical Engineering Faculty Research and Publications

Background: Novel powered prosthetic ankles currently incorporate finite state control, using kinematic and kinetic sensors to differentiate stance and swing phases/sub-phases and control joint impedance and position or torque. For more intuitive control, myoelectric control of the ankle using the remnant residual limb dorsiflexors and plantarflexors, perhaps in concert with kinetic and kinematic sensors, may be possible.

Objective: The specific research objective was to assess the feasibility of using myoelectric control of future active or powered prosthetic ankle joints for trans-tibial amputees.

Study Design: The project involved human subject trials to determine whether current techniques of myoelectric control of upper …

Diffusion Tensor Imaging And Tractography In Brown-Sequard Syndrome, A. Vendatam, Michael B. Jirjis, Brian D. Schmit, M. D. Budde, J. L. Ulmer, Mei Wang, S. N. Kurpad

Biomedical Engineering Faculty Research and Publications

This report illustrates the utility of DTI and DTT in delineating regions of cord injury in two patients with traumatic Brown-Sequard syndrome. Our results indicate that DTI provides clinically relevant information that supplements conventional MR imaging for patients with acute SCI.

Differential Lung Uptake Of 99mtc-Hexamethylpropyleneamine Oxime And 99mtc-Duramycin In The Chronic Hyperoxia Rat Model, Anne V. Clough, Said H. Audi, Steven Thomas Haworth, David L. Roerig

Biomedical Engineering Faculty Research and Publications

Noninvasive radionuclide imaging has the potential to identify and assess mechanisms involved in particular stages of lung injury that occur with acute respiratory distress syndrome, for example. Lung uptake of ^99mTc-hexamethylpropyleneamine oxime (HMPAO) is reported to be partially dependent on the redox status of the lung tissue whereas ^99mTc-duramycin, a new marker of cell injury, senses cell death via apoptosis or necrosis. Thus, we investigated changes in lung uptake of these agents in rats exposed to hyperoxia for prolonged periods, a common model of acute lung injury. Methods: Male Sprague–Dawley rats were preexposed to either normoxia (21% O …

Design Of A Pretreatment And Enzymatic Saccharification Scheme Of Understory From Managed Pine Forest For A Biochemical-Refinery Platform: The Example Of The Sweetgum Tree, Angele Djioleu

Graduate Theses and Dissertations

The possibility of using sweetgum from southern pine dominated forests as a biobased refinery feedstock was investigated. First, a baseline hydrolysis scheme for sweetgum wood and bark was designed. Sweetgum wood and bark were pretreated with 0.98% (v/v) sulfuric acid at 140°C for 30, 40, 50, 60 or 70 min and at 160°C for 30, 40, 50 or 60 min. The water insoluble solid (WIS) fraction was hydrolyzed with a cellulase enzyme cocktail. Results showed that maximum xylose and glucose yields from the wood were 82 and 86%, respectively. Similarly, the respective maximum yields of xylose and glucose from the …

A Watershed Scale Evaluation Of Selected Second Generation Biofeedstocks On Water Quality, Gurdeep Singh

Graduate Theses and Dissertations

This study compares a novel simulation approach to the conventional Soil and Water Assessment Tool (SWAT) modeler's approach for targeting biofuel crop production on marginal lands. In conventional SWAT modeling approach, non-spatial definition of hydrological response units (HRUs) results in the simulation of biofuel crops on both marginal and non-marginal land. This study provides an alternative approach in which a marginal-land raster was integrated into the land use and land cover (LULC) raster in such a way that the land uses were divided into marginal and non-marginal components. This modified LULC was used for model setup which resulted in marginal …

Bioswellable Amphiphilic Copolymers, David Ingram

All Theses

The suture is one of the most commonly used medical devices, consisting of a fiber, a surgical needle and the packaging in which it is stored. The fiber itself remains after implantation for a defined time and is responsible for the approximation of the wound during the healing process. The needle merely serves to aid in insertion, and preferably has a diameter larger than the diameter of the fiber .
The 1970's marked the birth of a new family of fibrous materials for the approximation of wounds: synthetic absorbable sutures. This family has the ability to provide wound support during …

Reducing In-Stent Restenosis Through Novel Stent Flow Field Augmentation, Eoin Murphy, Fergal Boyle

Articles

In-stent restenosis (ISR), manifested as a re-narrowing of the arterial lumen post-implantation of a stent, is a detrimental limitation of stent technology. Understanding and consequently devising ways of reducing the frequency of ISR has been a continuing goal of research into improved stent designs. The biological processes that can lead to ISR have been found to be partially flow dependent with the local hemodynamics at the arterial wall of crucial importance. This paper investigates these biological processes and their instigating factors. Furthermore, the history and theory behind three stent technologies which endeavour to reduce ISR rates through stent flow field …

Biodiesel Production From Mixed Culture Algae Via A Wet Lipid Extraction Procedure, Ashik Sathish

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Development of renewable sources of energy has received significant interest due to the rising costs of energy and the environmental impact of using fossil fuels. Biodiesel production from renewable sources of oil has shown promise of helping to replace or reduce dependence on petroleum based diesel thereby reducing demand for crude oil. Microalgae have been considered as a strong candidate for the production of large quantities of renewable oil for biodiesel production.

Microalgae are single cell photosynthetic organisms that posses the capability to produce renewable oil at rates much faster than land based plants and crops. In addition, microalgae can …

Measuring Impedance Of Tissues Using A Microfabricated Microelectrode Array, Ashwini Bhat

Master's Theses

MEASURING IMPEDANCE OF TISSUES USING A MICROFABRICATED MICROELECTRODE ARRAY By Ashwini Bhat

This thesis looks at the possibility of using impedance spectroscopy for differentiating tissue, using a microelectrode array (MEA). The thesis first discusses the background and the motivation for this thesis. It covers the certain basic concepts of the human skin starting from the top epidermis layer all the way to the deep dermis layers of the skin. Then it discusses different types of skin cancer and how they occur, in humans. It also discusses various microfabrication techniques such as oxidation, wet etching, sputtering and photolithography for the creation …

Morphometric, Biochemical, And Raman Spectral Analyses Of Muscle Damage In Patients With Peripheral Arterial Disease: Providing Objective Criteria For Diagnosis And Treatment Monitoring, Kim Cluff

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

Peripheral arterial disease (PAD), which affects approximately 10 million Americans, is characterized by atherosclerosis of the non-coronary arteries. PAD produces a progressive accumulation of ischemic injury to the limbs that is reflected in a gradual worsening in the myofiber morphology and oxidative damage in the gastrocnemius muscle. In this study, we evaluated the hypothesis that quantitative morphological and biochemical parameters of gastrocnemius myofibers change in a consistent manner during the progression of PAD, provide an objective grading of muscle degeneration in the ischemic limb, and correlate to clinical stage of PAD. Myofiber morphometrics were determined precisely with mathematical equations that …

Fabrication Of Cao-Nao-Sio2/Tio2 Scaffolds For Surgical Applications, A. W. Wren, A. Coughlan, K. E. Smale, S. T. Misture, B. P. Mahon, O. M. Clarkin, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

A series of titanium (Ti) based glasses were formulated (0.62 SiO₂-0.14 Na₂O-0.24 CaO, with 0.05 mol% TiO₂ substitutions for SiO₂) to develop glass/ceramic scaffolds for bone augmentation. Glasses were initially characterised using X-ray diffraction (XRD) and particle size analysis, where the starting materials were amorphous with 4.5 μm particles. Hot stage microscopy and high temperature XRD were used to determine the sintering temperature (̃700 °C) and any crystalline phases present in this region (Na₂Ca₃Si₆O₁₆, combeite and quartz). Hardness testing revealed that the Ti-free control (ScC- …

Melt Blown Poly(Lactic Acid) For Application As A Tissue Engineering Scaffold, William Horst Gazzola

Masters Theses

Poly(lactic acid) (PLA) was melt blown (MB) under varying processing conditions to create webs with micro and nano-architecture. Processing parameters varied were primary air flow rate and collector distance. In total, twenty-one webs were produced and the physical properties of the webs were investigated including, mean fiber diameter and fiber diameter distribution, mean pore diameter and pore size distribution, web thickness, degree of crystallinity, tensile modulus and degradation rate. Four webs, two with micro and two with nano-architecture, thought suitable for use as tissue engineering scaffolds were selected for seeding with A375 human malignant melanoma cells. Cell culture was conducted …

Application Of Response Surface Methodology And Central Composite Design For 5p12-Rantes Expression In The Pichia Pastoris System, Frank M. Fabian

Department of Chemical and Biomolecular Engineering: Theses and Student Research

Pichia pastoris has demonstrated the ability to express high levels of recombinant heterologous proteins. Protein expression is enhanced during fermentation at high cell density. However, the level of expression is mainly regulated by fermentation operation factors. This research is directed to investigate the effect of methanol growth rate, temperature and pH in the expression of the total 5P12-Rantes concentration, expression of active 5P12-Rantes and Specific yield using the response surface methodology and central composite design.

The response surface methodology, RSM, has been used successfully used by Zhang, W. and Ian, M. to optimize the cell density and fermentation process. The …

Implementation Of Magnetic Resonance Elastography For The Investigation Of Traumatic Brain Injuries, Thomas Boulet

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

Magnetic resonance elastography (MRE) is a potentially transformative imaging modality allowing local and non-invasive measurement of biological tissue mechanical properties. It uses a specific phase contrast MR pulse sequence to measure induced vibratory motion in soft material, from which material properties can be estimated. Compared to other imaging techniques, MRE is able to detect tissue pathology at early stages by quantifying the changes in tissue stiffness associated with diseases. In an effort to develop the technique and improve its capabilities, two inversion algorithms were written to evaluate viscoelastic properties from the measured displacements fields. The first one was based on …

Nanoroughened Surfaces For Efficient Capture Of Circulating Tumor Cells Without Using Capture Antibodies, Weiqiang Chen, Shinuo Weng, Feng Zhang, Steven Allen, Xiang Li, Liwei Bao, Raymond H. W. Lam, Jill A. Macoska, Sofia D. Merajver, Jianping Fu

Weiqiang Chen

Circulating tumor cells (CTCs) detached from both primary and metastatic lesions represent a potential alternative to invasive biopsies as a source of tumor tissue for the detection, characterization and monitoring of cancers. Here we report a simple yet effective strategy for capturing CTCs without using capture antibodies. Our method uniquely utilized the differential adhesion preference of cancer cells to nanorough surfaces when compared to normal blood cells and thus did not depend on their physical size or surface protein expression, a significant advantage as compared to other existing CTC capture techniques.

Development Of A Closed-Loop Force Reduction Mechanism In A Gait Rehabilitation Device, Jeffrey Frankart

Theses and Dissertations

Elliptical trainers are prescribed in rehabilitative exercise but difficult to implement in populations with significant functional gait deficits. Typical elliptical machines do not mimic normal gait and therefore require modifications for clinical rehabilitation. This research builds on previous modifications of an elliptical trainer designed to simulate level-surface walking. This design differed from a commercial version. It included articulated footplates and an electromechanically-driven virtual-cam to control footplate position. Ankle dorsiflexion elicited lower-extremity muscle spasticity which produced an unwanted gait variant during stroke patient testing. Spasticity is a hyperexcitable stretch reflex causing inefficient gait. This project’s purpose was to develop an autonomous …

Compression Transmission Collar For Fastening, Patrick Atkinson

Mechanical Engineering Patents

A compression transmission collar apparatus (20) for implantation into a bone (22) with a hole (28) having a hole wall (32) comprising an intramedullary nail (34) defining a bore (40) and a threaded fastener (42) and a compression transmission collar (58) including an exterior face (64) and a top edge (60) and a bottom edge (62) and a first end (70) intersecting the top edge (60) at an acute angle (α₁) and …

Geometrical Analysis And Modeling Of Craniosynostosis, Sahar Shahbazi

Electronic Thesis and Dissertation Repository

Craniosynostosis is a developmental abnormality in skull growth, due to the fusion of one or more sutures\cite{patho}. To accommodate the growing brain. the skull needs to grow quickly in the first few months of life, and most of the growth of the skull at that time occurs at the sutures. Craniosynostosis occurs when one or more sutures are fused in utero, resulting in an abnormal skull shape. Surgical intervention is usually required at a young age, and remodeling of the skull is done for cosmetic reasons as well as to avoid raised intracranial pressure. In order to study how the …

A Biomechanical Model For The Validation Of Modular Control In Balance, S. Piazza, M. Mansouri, D. Torricelli, Jeffrey A. Reinbolt, J. L. Pons

Jeffrey A. Reinbolt

No abstract provided.

Quantitative, Spectrally-Resolved Intraoperative Fluorescence Imaging, Pablo A. Valdés, Frederic Leblond, Valerie L. Jacobs, Brian C. Wilson, Keith D. Paulsen, David W. Roberts

Dartmouth Scholarship

Intraoperative visual fluorescence imaging (vFI) has emerged as a promising aid to surgical guidance, but does not fully exploit the potential of the fluorescent agents that are currently available. Here, we introduce a quantitative fluorescence imaging (qFI) approach that converts spectrally-resolved data into images of absolute fluorophore concentration pixel-by-pixel across the surgical field of view (FOV). The resulting estimates are linear, accurate, and precise relative to true values, and spectral decomposition of multiple fluorophores is also achieved. Experiments with protoporphyrin IX in a glioma rodent model demonstrate in vivo quantitative and spectrally-resolved fluorescence imaging of infiltrating tumor margins for the …

My Lecture Notes (Power Plant Engineering) - Chapter 3, Dr Alireza Zolfaghari

Dr Alireza Zolfaghari

No abstract provided.

Reviewing The American University Law Review On Extraterritoriality: A Critical Response To Viki Economides, Note, Tianrui Group Co. V. Itc: The Dubious Status Of Extraterritoriality And The Domestic Industry Requirement Requirement Of Section 337(Link), Jonathan Stroud

Articles in Law Reviews & Other Academic Journals

Recently, the Federal Circuit upheld the Commission’s decision to exclude goods based on a trade secret violation that largely happened abroad. The American University Law Review critiqued that decision on two grounds: First, that a presumption against extraterritorial application of U.S. law applied; and second, that licensing alone could not establish a domestic industry. The American University Law Review's critique remains incomplete, however, as the Federal Circuit correctly decided the case for at least two reasons. first, the Federal Circuit correctly applied the “extraterritorial presumption” canon of construction; and second, the recent Federal Circuit decision in InterDigital Communications LLC v. …

Reviewing The American University Law Review On Extraterritoriality: A Critical Response To Viki Economides, Note, Tianrui Group Co. V. Itc: The Dubious Status Of Extraterritoriality And The Domestic Industry Requirement Requirement Of Section 337(Link), Jonathan R. K. Stroud

Jonathan R. K. Stroud

Recently, the Federal Circuit upheld the Commission’s decision to exclude goods based on a trade secret violation that largely happened abroad. The American University Law Review critiqued that decision on two grounds: First, that a presumption against extraterritorial application of U.S. law applied; and second, that licensing alone could not establish a domestic industry. The American University Law Review's critique remains incomplete, however, as the Federal Circuit correctly decided the case for at least two reasons. first, the Federal Circuit correctly applied the “extraterritorial presumption” canon of construction; and second, the recent Federal Circuit decision in InterDigital Communications LLC v. …

Load-Relaxation Properties Of The Human Trunk In Response To Prolonged Flexion: Measuring And Modeling The Effect Of Flexion Angle, Nima Toosizadeh, Maury A. Nussbaum, Babak Bazrgari, Michael L. Madigan

Biomedical Engineering Faculty Publications

Experimental studies suggest that prolonged trunk flexion reduces passive support of the spine. To understand alterations of the synergy between active and passive tissues following such loadings, several studies have assessed the time-dependent behavior of passive tissues including those within spinal motion segments and muscles. Yet, there remain limitations regarding load-relaxation of the lumbar spine in response to flexion exposures and the influence of different flexion angles. Ten healthy participants were exposed for 16 min to each of five magnitudes of lumbar flexion specified relative to individual flexion-relaxation angles (i.e., 30, 40, 60, 80, and 100%), during which lumbar flexion …

Noninvasive Optical Characterization Of Muscle Blood Flow, Oxygenation, And Metabolism In Women With Fibromyalgia, Yu Shang, Katelyn Gurley, Brock Symons, Douglas Long, Ratchakrit Srikuea, Leslie J. Crofford, Charlotte A. Peterson, Guoqiang Yu

Biomedical Engineering Faculty Publications

INTRODUCTION: Women with fibromyalgia (FM) have symptoms of increased muscular fatigue and reduced exercise tolerance, which may be associated with alterations in muscle microcirculation and oxygen metabolism. This study used near-infrared diffuse optical spectroscopies to noninvasively evaluate muscle blood flow, blood oxygenation and oxygen metabolism during leg fatiguing exercise and during arm arterial cuff occlusion in post-menopausal women with and without FM.

METHODS: Fourteen women with FM and twenty-three well-matched healthy controls participated in this study. For the fatiguing exercise protocol, the subject was instructed to perform 6 sets of 12 isometric contractions of knee extensor muscles with intensity steadily …

First-Order Design Of A Reflective Viewfinder For Adaptive Optics Ophthalmoscopy, Alfredo Dubra, Yusufu N. Sulai

Biomedical Engineering Faculty Research and Publications

Adaptive optics (AO) ophthalmoscopes with small fields of view have limited clinical utility. We propose to address this problem in reflective instruments by incorporating a viewfinder pupil relay designed by considering pupil and image centering and conjugation. Diverting light from an existing pupil optical relay to the viewfinder relay allows switching field of view size. Design methods that meet all four centering and conjugation conditions using either a single concave mirror or with two concave mirrors forming an off-axis afocal telescope are presented. Two different methods for calculating the focal length and orientation of the concave mirrors in the afocal …

Tyrosine Nitration Of Voltage-Dependent Anion Channels In Cardiac Ischemia-Reperfusion: Reduction By Peroxynitrite Scavenging, Meiying Yang, Amadou K.S. Camara, Bassam T. Wakim, Yifan Zhou, Ashish K. Gadicherla, Wai-Meng Kwok, David F. Stowe

Biomedical Engineering Faculty Research and Publications

Excess superoxide (O₂⁻) and nitric oxide (NO) forms peroxynitrite (ONOO⁻) during cardiac ischemia reperfusion (IR) injury, which in turn induces protein tyrosine nitration (tyr-N). Mitochondria are both a source of and target for ONOO⁻. Our aim was to identify specific mitochondrial proteins that display enhanced tyr-N after cardiac IR injury, and to explore whether inhibiting O₂⁻/ONOO⁻ during IR decreases mitochondrial protein tyr-N and consequently improves cardiac function. We show here that IR increased tyr-N of 35 and 15 kDa mitochondrial proteins using Western blot analysis with 3-nitrotyrosine antibody. Immunoprecipitation …

Implementation Of Novel Group Delay Decomposition Method And Surgical Protocol For Assessing Peripheral Neuropathy, Sammy Paul Nicolas

Master's Theses

This paper outlines a surgical procedure for exposing and stimulating the sciatic nerve of an anesthetized rodent for purposes of obtaining conduction velocity readings. The ability to accurately quantify nerve conduction velocity has potential for use in the field of diagnostic medicine and disease characterization. An accurate reading depends on both the surgical method used to expose the desired nerve without imposing onto it any physical trauma as well as the stimulation protocol used to initiate action potentials. This paper contains the specific steps required to set up the necessary hardware and software for electrical stimulation as well as a …