Biomedical Engineering and Bioengineering Commons^™

Defining Sagittal Plane Gait Mechanics And Joint Loading In People With Marfan Syndrome, Justin Melan Pol

Theses and Dissertations--Biomedical Engineering

Marfan syndrome (MFS) is a genetic condition that is associated with altered muscle composition, which leads to muscle dysfunction. People with MFS exhibit high instances of lower extremity (LE) joint pain that inhibits their ability to perform activities of daily living, such as walking. Despite these detrimental impacts of MFS, there have been no attempts to characterize the effects of MFS on LE joint loading and health during walking that are associated with LE pain and dysfunction. As people with MFS exhibit a high incidence rate of osteoarthritis (OA), the need to understand the potential alterations in LE extremity mechanics …

3-Dimensional Muscle Constructs: Using Hydrogels In Order To Model The Effects Of Exercise In Disease Conditions, Mark Mchargue

Theses and Dissertations--Biomedical Engineering

Currently, there is no standard in vitro model for studying the effects of mechanical stimulation on muscle in type II diabetes. Existing models primarily utilize electrical stimulation, which does not fully recapitulate the effects of exercise. In this thesis, we create a standardized in vitro model of murine muscle that can recapitulate the benefits seen in exercise when mechanically stimulated. Moreover, we show that a type II diabetes environment has similar effects on the muscle in vitro as well as in vivo.

Multiscale And Multimodality Optical Imaging Of Brain Hemodynamics And Function, Mehrana Mohtasebi

Theses and Dissertations--Biomedical Engineering

Frequent measurement of cerebral hemodynamics is crucial for continuous assessment of brain function and health. Low-frequency oscillations (LFOs; < 0.1 Hz) have shown promise as an indicator of altered neurologic activity in the abnormal brain. Moreover, quantification of temporal correlations in LFOs across distinct brain regions enables mapping of regional neurovascular disorders. Portable diffuse optical techniques such as near-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS) enable noninvasive and continuous measurements of cerebral oxygenation and cerebral blood flow (CBF), respectively. However, most NIRS/DCS systems use limited numbers of discrete light sources and detectors and thus lack combinations of high temporal/spatial resolution and large field-of-view (FOV) for brain imaging. Recent development of an innovative noncontact speckle contrast diffuse correlation tomography (scDCT) in our lab provides a low-cost and portable tool for high-density imaging of CBF distributions over large FOVs. The scDCT uses a galvo-mirror to remotely deliver coherent point near-infrared light to multiple source positions and a CMOS camera as a high-density 2-D detector array to quantify spatial fluctuations of diffuse laser speckles, resulting from movement of red blood cells. Boundary CBF data were input to a unique finite-element-method (FEM)-based reconstruction algorithm for 3-D imaging of CBF distributions. However, scDCT was hindered for extracting LFOs due to its low sampling rate. In this study, scDCT was optimized to achieve high sampling rates and fast image reconstructions by use of moving window algorithms with parallel computations (Project 1). Power spectral density (PSD) analysis was performed to investigate altered LFOs during transient cerebral ischemia in neonatal piglets. Transient cerebral ischemia caused reductions in both CBF and PSD, supporting inclusion of scDCT in the growing field of LFO analysis. One remaining limitation was the long computational time required for 3-D reconstruction, which prohibited real-time applications. To overcome this limitation, a depth-sensitive diffuse speckle contrast topography (DSCT) method was developed for analyzing scDCT data to achieve fast and high-density 2-D mapping of CBF distribution without the need of complex and time-consuming 3-D reconstructions (Project 2). New head-simulating phantoms with known optical/geometric properties were designed and fabricated to evaluate the spatial resolution and depth sensitivity of DSCT method. In-vivo experiments verified the capability of DSCT in tracking dynamic changes in CBF at different depths during CO₂ inhalation and transient cerebral ischemia in rats. In addition to preclinical studies, a low-cost, wearable, fluorescence eye loupe (FLoupe) device was invented for intraoperative visualization of brain tumor margin in the clinic (Project 3). Consistent results were observed against an expensive, large, standard fluorescence operative microscope for the guidance of tumor resection. Overall, through 3 projects this dissertation demonstrated a variety of noninvasive noncontact optical technologies (scDCT, DSCT, and FLoupe) that enabled multiscale (rodents, piglets, and humans) and …

A Wearable Fiber-Free Optical Sensor For Continuous Measurements Of Cerebral Blood Flow And Oxygenation, Xuhui Liu

Theses and Dissertations--Biomedical Engineering

Wearable technologies for continuous monitoring of cerebral hemodynamics in freely behaving subjects not only advance our understanding of cognitive processing and adaptive behavior, but also provide vital information for diagnosis and therapeutic assessment of cerebral diseases associated with hypoxia/ischemia. Wearable near-infrared diffuse optical techniques have been used at the bedside to probe deep cerebral hemodynamics, including near-infrared spectroscopy (NIRS) for cerebral oxygenation measurement and diffuse correlation spectroscopy (DCS) for cerebral blood flow (CBF) measurement, respectively. However, most systems are relatively large and expensive, and use rigid fiber-optic probes that significantly constrain subject’s movement. A novel, wearable, fiber-free diffuse speckle contrast …

Microalgae Immobilization With Filamentous Fungi: Process Development For Sustainable Food Systems, Suvro Talukdar

Theses and Dissertations--Biosystems and Agricultural Engineering

Demand for sustainable food sources has increased because of the rapid growth of the world's population.  In this study, microalgae cells of Haematococcus pluvialis were immobilized using the edible fungal strain Aspergillus awamori for potential food applications. The study investigated the impact of fungal loading, pellet geometry, and initial microalgae cell concentration on the immobilization performance and product characteristics. It was found that higher fungal loading and larger fungal pellets contributed to increased immobilization performance while increased initial microalgae concentration inhibited the process. Larger fungal pellets had decreased biomass density, which led to decreased surface concentration of immobilized microalgae but …

Using Paired-Agent Imaging To Track Changes In Head And Neck Cancers After Undergoing Photodynamic Therapy Treatment, Reeham M. Choudhury

Dartmouth College Master’s Theses

Head and neck cancers affect thousands of people across the world, and photodynamic therapy (PDT) has been shown to have great potential to treat said cancers in a noninvasive manner. However, imaging head and neck cancers has been difficult, and molecular changes caused by PDT are not well-understood. Therefore, we propose the use of paired-agent imaging (PAI) to track changes in these cancers after after PDT treatment. For these studies, we primarily used benzoporphyrin derivative monoacid (BPD) for our photosensitizer, which is activated by a 690 nm laser. We first looked at changes in EGFR expression in vitro, and …

High Throughput Cellular Screening Technologies For Engineering Enhanced-Solubility And Deimmunized Biologics, Andrew Y. Chang

Dartmouth College Ph.D Dissertations

High throughput cell-based screening methodologies have become core development tools for the generation and engineering of various biotherapeutics. For example, SpCas9 variants for use in CRISPR-Cas9 therapeutics have been engineered for enhanced specificity using a high throughput directed evolution approach in E. coli. Additionally, antibodies are routinely discovered and engineered for high affinity binding using yeast surface display. These high throughput techniques typically involve generation of large protein libraries which require innovative screening strategies depending on the target protein’s function. In this thesis work, we describe high throughput protein library screening approaches to address recombinant biologic aggregation and immunogenicity …

Marineepi: A Gui-Based Matlab Toolbox To Simulate Marine Pathogen Transmission, Gorka Bidegain, Tal Ben-Horin, Eric N. Powell, John M. Klinck, Eileen E. Hofmann

CCPO Publications

The Graphical User Interface (GUI) MarineEpi is presented as a Matlab toolbox for easily (i) constructing disease transmission models for different marine host-pathogen systems, (ii) running simulations by specifying initial conditions and model parameters, and (iii) interpreting the resulting time series of the host and pathogen population dynamics. MarineEpi users can generate models for systems in which pathogen transmission occurs through contact with infected individuals (SI), contact with dead infected individuals (SID), contact with environmental pathogens released by infected individuals (SIP), and contact with environmental pathogens released by dead infected individuals (SIPD). MarineEpi is a freely available GUI that provides …

Life Cycle Assessment Of Air Classification As A Sulfur Mitigation Technology In Pine Residue Feedstocks, Ashlee Edmonson

Theses and Dissertations--Biosystems and Agricultural Engineering

Sulfur accumulation during biofuel production is pollutive, toxic to conversion catalysts, and causes the premature breakdown of processing equipment. Air classification is an effective preprocessing technology for ash and sulfur removal from biomass feedstocks. A life cycle assessment (LCA) sought to understand the environmental impacts of implementing air classification as a sulfur-mitigation technique for pine residues. Energy demand and material balance for preprocessing were simulated using SimaPro and the Argonne National Laboratory’s GREET model, specifically focusing on comparing the global warming potential (GWP) of grid electricity versus bioelectricity scenarios. Overall, the grid electricity scenario had a GWP impact over 7 …

Chronic Anemia Revealing An Idiopathic Watermelon Stomach: Case Report, Hanane Delsa, Imane Rahmouni, Yassamin Benhayoun Sadafyine, Fatima Belabbes, Anass Nadi, Fedoua Rouibaa

Health Sciences

Watermelon stomach, also known as gastric antral vascular ectasia (GAVE) syndrome, is a rare entity. Patients often present with profound unexplained anemia with or without bleeding externalization. We made the diagnosis during a digestive endoscopy for an etiological assessment of this anemia. Endoscopically, antral erythematous lesions in stripes with a punctate appearance, sometimes hemorrhagic, may suggest a watermelon stomach. The pathophysiology of the watermelon stomach remains complex and unclear. Although several pathologies remain implicated, sometimes, it can be idiopathic. The effectiveness of numerous treatments has been evaluated with relatively satisfactory results. This is a rare case of an idiopathic watermelon …

The Strength Of Motivation For Dental Students, Manal Elhijazi, Ihsane Benyahya

Health Sciences

Context: Motivation plays a key role in academic success. It is a dynamic process that maintains perseverance and tenacity in the face of difficulty. The purpose of our study was to measure and compare the strength of dental students' motivation at the beginning and the end of their training Material and methods: an anonymous self-administered voluntary questionnaire was distributed to 1st and 6th year students at the Faculty of Dentistry in Casablanca This questionnaire consisted of 30 closed questions divided into 3 sections, the first of which provided information on socio-demographic data, the second is devoted to measuring the strength …

Sodium Hyaluronate Based Drug Delivery To The Outer And Inner Ear, Emma Barrett-Catton

Graduate Student Theses, Dissertations, & Professional Papers

We have developed two projects using sodium hyaluronate (HA)-based systems for drug delivery to the ear. First, we investigated an HA-based hydrogel for use as a single use antibiotic treatment for otitis externa. Otitis externa, also known as outer ear infection, is a frequent affliction in both humans and animals. The most prevalent treatment for otitis externa is ear drops, but it is difficult to adhere properly to this treatment, causing poor patient compliance and the potential for complications. As a result, we have developed an HA-based hydrogel for use as a single application treatment for otitis externa to increase …

Development Of A Solution Synthesis Of Poly(Sebacic Anhydride) With The Activating Agent 4-Toluenesulfonyl Chloride: Understanding The Effect Of Different Bases On The Reaction Products, Patricia Poley

Honors Theses

The overall goal of this honors thesis was to develop a solution synthesis of Poly(Sebacic Anhydride) with the activating agent 4-toluenesulfonyl chloride and understand the effects of varying temperature, bases, and the addition order of reagents on the reaction.

Polyanhydrides are a class of hydrophobic, degradable polymers used in controlled drug delivery for 30 years. They are synthesized through three general methods: melt polycondensation, solution polycondensation, and ring-opening polymerization. Of these three methods, solution polycondensation typically results in products with lower molecular weight. Previous work in the Vogel lab identified two new ways to synthesize anhydrides using solution polycondensation reactions …

Exploring Ph Gradient Phenomena In Non-Linear Electrokinetic Microfluidic Devices, Azade Tahmasebi

Dissertations, Master's Theses and Master's Reports

Electrokinetic microfluidics is a versatile technology utilized within lab on a chip (LOC) devices for diagnostic and analytical applications; advantages include reduced resource demands, flexibility, and simplicity of use. Dielectrophoresis (DEP) is a precision nonlinear electrokinetic tool utilized within microfluidic microdevices to induce polarization and control bioparticle motions for applications that range from hemoglobin separations to cancer cell isolation and detection. Despite promising results, undesired side phenomena can occur in electrokinetic systems which impede reproducibility and accuracy. These unfavorable phenomena have not been comprehensively explored in the literature. Prior preliminary research suggests the fundamental phenomena originate from microelectrodes utilized in …

An Acute Respiratory Distress Syndrome Drug Development Collaboration Stimulated By The Virginia Drug Discovery Consortium, John S. Lazo, Ruben M.L. Colunga-Biancatelli, Pavel A. Solopov, John D. Catravas

Bioelectrics Publications

The genesis of most older medicinal agents has generally been empirical. During the past one and a half centuries, at least in the Western countries, discovering and developing drugs has been primarily the domain of pharmaceutical companies largely built upon concepts emerging from organic chemistry. Public sector funding for the discovery of new therapeutics has more recently stimulated local, national, and international groups to band together and focus on new human disease targets and novel treatment approaches. This Perspective describes one contemporary example of a newly formed collaboration that was simulated by a regional drug discovery consortium. University of Virginia, …

Editorial: Pulsed Electric Field Based Technologies For Oncology Applications, Siqi Guo, Gregor Sersa, Richard Heller

Bioelectrics Publications

No abstract provided.

Brain Morphometry From Neuroimaging As A Biomarker For Alzheimer's Disease, Nonyelum Benedicta Aniebo

Browse all Theses and Dissertations

Alzheimer’s disease (AD) is the seventh leading cause of death globally with an estimated 6.5 million Americans aged 65 and above living with Alzheimer’s dementia in 2022 and at a projected national cost of $321 billion. AD is characterized by a progressive and irreversible neurodegenerative dysfunction with clinical symptoms such as deterioration in cognition and memory loss. The Alzheimer’s Disease Neuroimaging Initiative (ADNI) is a multi-site, public-private global research initiative that supports both investigation and development of treatments that slow or terminate AD progression. The study included 60 participants, comprising 30 AD and 30 control cohorts respectively. All participants were …

Thermotrophy Exploratory Study, James Weifu Lee

Chemistry & Biochemistry Faculty Publications

The question of whether environmental heat energy could be utilized as a source of energy for biological metabolism is the center of this exploratory research. In 1979, this author postulated a hypothesis for the existence of thermotrophs that could isothermally utilize environmental heat energy as a source of their energy on Earth. According to this hypothesis, the thermotrophs could be the first primitive forms of life in the early Earth environment. The chemotrophs and phototrophs that we currently are all well familiar with might have been evolved somehow from the primitive thermotrophs. Furthermore, all the organisms currently regarded as the …

Telp Theory: Elucidating The Major Observations Of Rieger Et Al. 2021 In Mitochondria, James Weifu Lee

Chemistry & Biochemistry Faculty Publications

The transmembrane-electrostatically localized protons (TELP) theory may represent a complementary development to Mitchell's chemiosmotic theory. The combination of the two together can now excellently explain the energetics in mitochondria. Our calculated transmembrane-attractive force between an excess proton and an excess hydroxide explains how TELP may stay within a 1-nm thin layer at the liquid-membrane interface. Consequently, any pH sensor (sEcGFP) located at least 2–3 nm away from the membrane surface will not be able to see TELP. This feature as predicted from the TELP model was observed exactly in the experiment of Rieger et al., 2021. In contrast to their …

Modeling The Production Of Microalgal Biomass In Large Water Resource Recovery Facilities And Its Processing Into Various Commodity Bioproducts, James Pierson, Gopi Raju Makkena, Sandeep Kumar, Vinod Kumar, Vivekanand Vivekanand, Hasan Husain, Muhammad Ayser, Venkatesh Balan

Civil & Environmental Engineering Faculty Publications

Algae are capable of sequestering nutrients such as nitrates and phosphates from wastewater in the presence of sunlight and carbon dioxide (CO₂) to build up their body mass and help combat climate change. In the current study, we carried out different case studies to estimate the volume of algal biomass that could be produced annually using the rotating algal biofilm (RAB) method in three large-scale water resource recovery facilities (WRRFs) in Texas: Fort Worth, Dallas, and Houston. We calculated the total amount of lipids, carbohydrates, and proteins that could be fractionated from the algal biomass while using the …