Biomedical Engineering and Bioengineering Commons^™

Eye Movement And Pupil Measures: A Review, Bhanuka Mahanama, Yasith Jayawardana, Sundararaman Rengarajan, Gavindya Jayawardena, Leanne Chukoskie, Joseph Snider, Sampath Jayarathna

Computer Science Faculty Publications

Our subjective visual experiences involve complex interaction between our eyes, our brain, and the surrounding world. It gives us the sense of sight, color, stereopsis, distance, pattern recognition, motor coordination, and more. The increasing ubiquity of gaze-aware technology brings with it the ability to track gaze and pupil measures with varying degrees of fidelity. With this in mind, a review that considers the various gaze measures becomes increasingly relevant, especially considering our ability to make sense of these signals given different spatio-temporal sampling capacities. In this paper, we selectively review prior work on eye movements and pupil measures. We first …

Customer Gaze Estimation In Retail Using Deep Learning, Shashimal Senarath, Primesh Pathirana, Dulani Meedeniya, Sampath Jayarathna

Computer Science Faculty Publications

At present, intelligent computing applications are widely used in different domains, including retail stores. The analysis of customer behaviour has become crucial for the benefit of both customers and retailers. In this regard, the concept of remote gaze estimation using deep learning has shown promising results in analyzing customer behaviour in retail due to its scalability, robustness, low cost, and uninterrupted nature. This study presents a three-stage, three-attention-based deep convolutional neural network for remote gaze estimation in retail using image data. In the first stage, we design a mechanism to estimate the 3D gaze of the subject using image data …

Minimally Invasive In Vivo Endoscopic Monitoring Of Dextran Sulfate Sodium-Induced Murine Colitis, Elizabeth A. Bullard, Ariel I. Mundo, Shelby N. Bess, Kathryn Miller Priest, Timothy J. Muldoon

Biomedical Engineering Faculty Publications and Presentations

Ulcerative colitis (UC) is a gastrointestinal, autoimmune disease that causes ulceration and inflammation of the colon with an incidence of 10 out of every 100,000 people in North America and Western Europe. Though the specific cause is unknown, several studies have demonstrated that inflammatory cells as well as environmental variables, genetics, and lifestyle behaviors can play a role in the long-term inflammatory response. Researchers have commonly used immunohistochemistry, western blotting and gene sequencing to establish the cellular processes behind UC relapse and remission. However, because these destructive methods necessitate the removal of a sample, they can only be used on …

Immunomodulatory Functions Of Human Mesenchymal Stromal Cells Are Enhanced When Cultured On Hep/Col Multilayers Supplemented With Interferon-Gamma, Mahsa Letter-Mahsa Haseli, David A. Castilla-Casadiego, Luis Carlos Pinzon-Herrera, Alexander Hillsley, Katherine A. Miranda-Munoz, Srikanth Sivaraman, Adrianne M. Rosales, Raj R. Rao, Jorge Almodovar

Chemical Engineering Faculty Publications and Presentations

Human mesenchymal stromal cells (hMSCs) are multipotent cells that have been proposed for cell therapies due to their immunosuppressive capacity that can be enhanced in the presence of interferon-gamma (IFN-γ). In this study, multilayers of heparin (HEP) and collagen (COL) (HEP/COL) were used as a bioactive surface to enhance the immunomodulatory activity of hMSCs using soluble IFN-γ. Multilayers were formed, via layer-by-layer assembly, varying the final layer between COL and HEP and supplemented with IFN-γ in the culture medium. We evaluated the viability, adhesion, real-time growth, differentiation, and immunomodulatory activity of hMSCs on (HEP/COL) multilayers. HMSCs viability, adhesion, and growth …

Visual Oscillation Effects On Dynamic Balance Control In People With Multiple Sclerosis, Lara I. Riem, Scott A. Beardsley, Ahmed Z. Obeidat, Brian D. Schmit

Biomedical Engineering Faculty Research and Publications

Background: People with multiple sclerosis (PwMS) have balance deficits while ambulating through environments that contain moving objects or visual manipulations to perceived self-motion. However, their ability to parse object from self-movement has not been explored. The purpose of this research was to examine the effect of medial-lateral oscillations of the visual field and of objects within the scene on gait in PwMS and healthy age-matched controls using virtual reality (VR).

Methods: Fourteen PwMS (mean age 49 ± 11 years) and eleven healthy controls (mean age: 53 ± 12 years) participated in this study. Dynamic balance control was assessed while participants …

Raman Spectroscopy Reveals Phenotype Switches In Breast Cancer Metastasis, Santosh Kumar Paidi, Joel Rodriguez Troncoso, Mason G. Harper, Zhenhui Liu, Khue G. Nguyen, Sruthi Ravindranathan, Lisa Rebello, David E. Lee, Jesse D. Ivers, David A. Zaharoff, Narasimhan Rajaram, Ishan Barman

Biomedical Engineering Faculty Publications and Presentations

The accurate analytical characterization of metastatic phenotype at primary tumor diagnosis and its evolution with time are critical for controlling metastatic progression of cancer. Here, we report a label-free optical strategy using Raman spectroscopy and machine learning to identify distinct metastatic phenotypes observed in tumors formed by isogenic murine breast cancer cell lines of progressively increasing metastatic propensities. Methods: We employed the 4T1 isogenic panel of murine breast cancer cells to grow tumors of varying metastatic potential and acquired label-free spectra using a fiber probe-based portable Raman spectroscopy system. We used MCR-ALS and random forests classifiers to identify putative spectral …

Combinatorial Approaches For Effective Design, Synthesis, And Optimization Of Enzyme-Based Conjugates, Jordan Scott Chapman

Graduate Theses, Dissertations, and Problem Reports (ETD)

The specificity and efficiency with which enzymes catalyze selective chemical reactions far exceeds the performance of traditional heterogeneous catalysts that are predominant in industrial applications such as conversion of commodity chemicals to value-added products, fuel cells, and petroleum refinement. Moreover, biocatalysts exhibit exceptionally high product turnover at ambient conditions with little health and environmental burden. These advantageous qualities have led to the prolific use of enzyme catalysis in pharmaceutical, detergents, and food preservation industries wherein their use has greatly reduced waste generation, Unfortunately, the full slate of benefits that enzymes can impart to a broader range of chemical processes is …

Gan-Based Super-Resolution And Segmentation Of Retinal Layers In Optical Coherence Tomography Scans, Paria Jeihouni

Graduate Theses, Dissertations, and Problem Reports (ETD)

Optical Coherence Tomography (OCT) has been identified as a noninvasive and cost-effective imaging modality for identifying potential biomarkers for Alzheimer's diagnosis and progress detection. Current hypotheses indicate that retinal layer thickness, which can be assessed via OCT scans, is an efficient biomarker for identifying Alzheimer's disease. Due to factors such as speckle noise, a small target region, and unfavorable imaging conditions manual segmentation of retina layers is a challenging task. Therefore, as a reasonable first step, this study focuses on automatically segmenting retinal layers to separate them for subsequent investigations. Another important challenge commonly faced is the lack of clarity …

Nano-, Encapsulated Manganese Oxide (Nemo) Particles For Mri Enhancement In Microfluidic Tumor Models, Kasey Alexis Freshwater

Graduate Theses, Dissertations, and Problem Reports (ETD)

Breast cancer is among the deadliest cancers in women, with approximately 2.3 million new cases and 685,000 deaths reported globally in 2020 alone. Magnetic Resonance Imaging (MRI) is commonly used to diagnose, stage, and develop treatment plans for patients predisposed to breast cancer. However, current MRI-based screening of breast cancer has high false-positive rates up to 25%, leading to unnecessary invasive follow-up screening and testing. The gold-standard intravenous gadolinium (Gd)-based contrast agents (GBCAs) account for false-positive rates because they are always “ON”, providing a constant MRI signal that highlights both benign and malignant tumors. The work detailed in this thesis …

Multi-Task Neuromuscular Generalization And Changes Through The Lifespan, Hannah Delaney Carey

Graduate Theses, Dissertations, and Problem Reports (ETD)

Mobility in everyday life requires executing and shifting between a broad assortment of functional tasks and resisting disturbances that could cause falls. Though the importance of successfully performing a variety of functional tasks is recognized and incorporated in clinical assessments (e.g., the Timed-Up-and-Go Test, Berg Balance Scale), little is understood about the underlying neuromuscular control required, or how it changes with age. The neuromuscular control for functional tasks such as walking is typically studied in isolation, or with variations on the same task. Characterizing the coordination required to produce and shift between a wider variety of tasks and resist external …

Characterizing Locomotor Disturbance Perception In Young Adults, Daniel James Liss

Graduate Theses, Dissertations, and Problem Reports (ETD)

Falls during walking are a leading cause of injuries across aging. Many of these falls are due to slips and trips. The ability to perceive disturbances to ongoing motion may play an important role in the control of walking balance. However, disturbance perception has been investigated in standing balance, but its role in walking balance due to slip- and trip-like disturbances remains largely unknown. Characterizing locomotor disturbance perception in young adults may lead to a more comprehensive understanding of sensorimotor walking balance control.

This work defined locomotor disturbance perception in response to slip and trip-like disturbances in young adults. We …

Tumor-Targeted Ph-Sensitive Manganese Oxide Nanoparticle For Enhanced Detection Of Breast Cancer Using Mri, Celia Martinez De La Torre

Graduate Theses, Dissertations, and Problem Reports (ETD)

In the United States, approximately 287,850 new cases of invasive breast cancer will be diagnosed, and over 43,000 women will die because of it in 2022. Currently, mammography is the gold standard for breast cancer surveillance. Although this detection technique is relatively cheap and fast, it misses about 1 in 5 breast cancers in younger women with dense breast tissue, causing a delay in treatment. Compared to mammography, magnetic resonance imaging (MRI) has superior soft-tissue contrast that elucidates structural differences within soft tissue to detect more breast cancers. However, MRI still misses

NEMO particles were produced by synthesizing manganese oxide …

An Antimicrobial Polydopamine Surface Coating To Reduce Biofouling On Telemetry Tags Used In Marine Conservation Practices, Ariana Smies

Dissertations, Master's Theses and Master's Reports

Satellite telemetry tags are used to track the migration patterns of large cetaceans. These tags penetrate the dermis and remain embedded in the underlying blubber tissue. As the dermis of cetaceans is host to a diverse microbiome, and it is impossible to clean the skin before implanting the devices, the potential for infection is increased when the tags penetrate through the skin. H₂O₂ is a potential antimicrobial agent that, in addition to showing broad-spectrum efficacy against gram-negative and gram-positive bacteria, can promote wound healing outcomes by promoting proliferative factors and peptides that protect against oxidative stress. However, …

Phase-Changing Nanodroplets As Nanotheranostic Platform For Combination Cancer Therapy, Catalina-Paula Spatarelu

Dartmouth College Ph.D Dissertations

Cancer is a cluster of diseases, and 1.8 million Americans are newly diagnosed each year. Treatment issues such as drug instability, the occurrence of severe side effects, as well as resistance make the need for solutions to improve conventional methods, like chemotherapy, apparent. Nano-sized drug-delivery platforms, particles loaded with therapeutic molecules that escape the immune system clearance and accumulate at the tumor site, were proposed as one of these solutions. Despite the expansion of the field, several aspects still need to be addressed: inconsistent delivery of the drugs, inability of measuring the effective dose being delivered to the tumor, lack …

Advancing Combined Radiological And Optical Scanning For Breast-Conserving Surgery Margin Guidance, Samuel Stewart Streeter

Dartmouth College Ph.D Dissertations

Breast cancer is one of the most common types of cancer worldwide, and standard-of-care for early-stage disease typically involves a lumpectomy or breast-conserving surgery (BCS). BCS involves the local resection of cancerous tissue, while sparring as much healthy tissue as possible. State-of-the-art methods for intraoperatively evaluating BCS margins are limited. Approximately 20% of BCS cases result in a tissue resection with cancer at or near the resection surface (i.e., a positive margin). A two-fold increase in ipsilateral breast cancer recurrence is associated with the presence of one or more positive margins. Consequently, positive margins often necessitate costly re-excision procedures to …

Exploring Cell Differentiation Vs. Localization In Engineered Ligament-To-Bone Entheses, Saagar N. Sheth, Michael E. Brown, Jennifer L. Puetzer

Undergraduate Research Posters

The anterior cruciate ligament (ACL) connects to bone via structurally complex insertions known as entheses that translate load from elastic ligament and stiff bone via gradients in organization, composition, and cell phenotype [1]. These gradients are not recreated in graft repair or engineered replacements, yielding limited repair options and high failure rates [2]. Previously, we developed a culture system that uses a tensile-compressive interface to guide ligament fibroblasts to develop early postnatal-like entheses by 6 weeks [3]; however, cells used were isolated from the entirety of the neonatal bovine ACL from bone to bone and likely contained multiple cell phenotypes …

A Highly Conductive, Flexible, And 3d-Printable Carbon Nanotube-Elastomer Ink For Additive Bio-Manufacturing, Andy Shar, Phillip Glass, Daeha Joung Ph.D.

Undergraduate Research Posters

The synthesis of a highly conductive, flexible, 3D-printable, and biocompatible ink has been of great interest in the field of bio-based additive manufacturing. Various applications include ultra-sensitive, microscale tactile sensors, patient-customizable scaffolds for cardiac and nerve tissue regeneration, and flexible electrocardiogram (ECG) electrodes. Here, a novel elastomeric carbon nanocomposite is presented consisting of amino-functionalized carbon nanotubes (CNT-NH₂) homogenously dispersed in a one-part room-temperature vulcanizing (RTV) silicone matrix. The use of acetone as a swelling solvent aids in electrical percolation through the elastomer matrix. CNT-NH₂ ratios can be tuned to fit various needs; higher tensile strength is favored …

Synthesis And Characterization Of Glycosaminoglycan Mimetic Variants For Cartilage Tissue Engineering Applications, Richard David Vincent Jr.

Dissertations

No abstract provided.

Rapid Ac Electrokinetic Micromixer With Electrically Conductive Sidewalls, Fang Yang, Wei Zhao, Cuifang Kuang, Guiren Wang

Faculty Publications

We report a quasi T-channel electrokinetics-based micromixer with electrically conductive sidewalls, where the electric field is in the transverse direction of the flow and parallel to the conductivity gradient at the interface between two fluids to be mixed. Mixing results are first compared with another widely studied micromixer configuration, where electrodes are located at the inlet and outlet of the channel with electric field parallel to bulk flow direction but orthogonal to the conductivity gradient at the interface between the two fluids to be mixed. Faster mixing is achieved in the micromixer with conductive sidewalls. Effects of Re numbers, applied …

Antimicrobial Susceptibility Of P. Aeruginosa Clinical Isolates, Tian Gao

Theses - ALL

Long-term infection caused by P. aeruginosa poses a major threat to personal and public health, and causes billions of dollars in medical expenses. To develop more effective controls, it is important to accurately evaluate antibiotic susceptibility of clinical isolates and understand how susceptibility changes during the course of infection. Conventional drug susceptibility tests using nutrient-rich media have been questioned regarding their relevance due to the difference between the model in vivo test conditions and the environment in the patients. Here, we report that 27 clinical strains of P. aeruginosa isolated from cystic fibrosis patients showed higher drug resistance in Artificial …