Biomedical Engineering and Bioengineering Commons^™

Polystyrene Nanoplastics As Pfas Carriers And Their Interactions With Zwitterionic Phospholipid Membranes, Jiahuiyu Fang, Tongxuan Qiao, Pranab Sarker, Xiaoxue Qin, Size Zheng, Mark J. Uline, Tao Wei

Faculty Publications

The co-occurrence of per- and polyfluoroalkyl substances (PFAS) and nanoplastics (NPs) poses a synergistic threat to environmental and human health, yet the molecular mechanisms governing PFAS–NP complexation and membrane interactions remain unclear. Using atomistic molecular dynamics simulations, we investigated the adsorption of neutral polytetrafluoroethylene (PTFE) and anionic perfluorinated compounds (perfluorooctanoic acid, PFOA, and perfluorooctanesulfonic acid, PFOS) on polystyrene NPs (3.1 and 6.7 nm) and their interactions with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) membranes. Polystyrene NPs act as carriers, transporting PFAS molecules to the lipid/water interface, where PFAS attachment modifies NP interfacial behavior. PFAS adsorption on the NP surface is driven by …

Methods For Radiation-Sparing Navigation In Endovascular And Spine Surgery, William Ross Warner

Dartmouth College Ph.D Dissertations

Modern surgical navigation systems improve procedural accuracy, limit complications, and can reduce reliance on intraoperative ionizing radiation, yet their adoption remains uneven across surgical domains. Informed by clinical immersion, this thesis identifies and addresses two unmet needs revealed through contrasting image-guidance practices in endovascular and spine surgery, where existing guidance techniques are costly, intermittent, or fundamentally limited. Specifically, these needs include (1) the absence of radiation-sparing navigation techniques for endovascular procedures, which rely heavily on 2D x-ray angiography, and (2) the need for dynamic registration methods in open spine surgery, where navigation accuracy can degrade after initial registration and intraoperative …

Volumetric Wear Analysis Of Polyethylene Orthopedic Liners Using Point Clouds, Gabriel Landi

Dartmouth College Master’s Theses

In vivo wear of ultra-high molecular weight polyethylene (UHMWPE) orthopedic bearings represents a major problem in shoulder and knee arthroplasty, with significant amounts of devices failing due to the complication itself, and even more due to associated reasons for retrieval, including aseptic loosening. However, quantification of UHMWPE wear has largely been limited to linear and in vitro volumetric analyses, obscuring the understanding of the amount of clinically relevant material loss. This study proposes new methods to measure articular, rim, and backside surfaces of retrieved shoulder and knee UHMWPE liners, centered around the coordinate measuring machine (CMM)-based collection of high density …

Accuracy Of Glenohumeral Joint Center Of Rotation Estimates Using Traditional Motion Capture Versus Bi-Plane Fluoroscopy, Julia A. Dunn, Ola Alsaadi, Kevin Shelburne, Michelle B. Sabick

Mechanical and Materials Engineering: Faculty Scholarship

Accurate estimation of the glenohumeral joint center of rotation is critical for biomechanical modeling of shoulder motion. This study evaluated the accuracy of three predictive methods for estimating glenohumeral joint center of rotation using optical motion capture, compared against a benchmark derived from synchronous bi-plane fluoroscopy. Five healthy adults performed shoulder abduction, flexion, and external rotation in 90° abducted and adducted positions. Root mean square error and axial errors were calculated across the full range of motion. Results showed that none of the predictive methods met clinically acceptable thresholds, with absolute error exceeding 10 mm and axial errors surpassing ±5 …

Enhancing Wound Healing With Synergistic Dual-Drug Electrospun Roflumilast And L-Arginine Loaded Pla/Pva Nanofibers Through Fabrication, Optimization, And In Vivo Assessment, Samar A. Salim

Nanotechnology Research Centre

Current trends in improved wound management emphasize the development of dual-drug-loaded electrospun nanofibrous scaffolds. Herein, electrospun dual-drug loaded PLA/PVA nanofibrous scaffolds, incorporating roflumilast, a selective phosphodiesterase-4 inhibitor with anti-inflammatory activity, and L-arginine, a precursor to nitric oxide with stimulating activity towards wound healing and tissue regeneration, were developed. A dual-spinneret electrospinning process enabled the coloading of drugs in PLA and PVA phases. Scaffolds were characterized by SEM, FTIR, and XRD, showing consistent fiber morphology, and amorphous drug formation. FTIR analysis was performed to confirm drug–polymer compatibility and successful incorporation of roflumilast and L-arginine within the PLA/ PVA nanofibrous matrix. Swelling …

Capturing Sclera Anisotropy Using Direct Collagen Fiber Models: Linking Microstructure To Macroscopic Mechanical Properties, Fengting Ji, Xuehuan He, Frederick Sebastian, Mohammad R. Islam, Hannah Schilpp, Bingrui Wang, Yi Hua, Rouzbeh Amini, Ian A. Sigal

Mechanical Engineering Faculty Publications

Collagen fibers are essential to the mechanical behavior of soft tissues, including sclera. Conventional models often represent these fibers statistically, potentially missing crucial aspects of their role in tissue behavior. In this study, we expand on a direct fiber modeling approach that we recently presented based on explicitly representing the sclera long, interwoven fiber bundles. Specifically, our goal was to capture specimen-specific 3D fiber architecture and anisotropic mechanics of four ovine sclera samples (superior from Eye-1, temporal and superior from Eye-2, and temporal from Eye-3), each tested under five conditions: equi-biaxial (1:1) and four non-equi-biaxial (1:0.75, 0.75:1, 1:0.5, and 0.5:1). …

Novel Repurposing Of Empagliflozin-Loaded Buccal Composite (Chitosan/Silk Fibroin/Poly(Lactic Acid)) Nanofibers For Alzheimer’S Disease Management Via Modulation Of Aβ–Ager–P-Tau Pathway, Samar A. Salim

Nanotechnology Research Centre

Background/Objectives: Empagliflozin (EMPA) was repurposed for Alzheimer’s disease (AD) treatment via buccal delivery, exploiting novel nanofibers (NFs) integrating chitosan (Cs), silk fibroin (Fb), and poly(lactic acid) (PLA). Methods: EMPA-loaded Cs/Fb/PLA NFs were electrospun in different formulations to optimize the formulation parameters. The optimized formulation was then investigated for its enhanced in vivo effect. Results: Optimized nanofiber diameters ranged from 459 ± 173 to 668 ± 148 nm, possessing bead-free morphology confirmed by SEM and satisfactory mechanical properties. EMPA was successfully well-dispersed in the polymer matrix as evidenced by FTIR, XRD, and drug content. The optimized NFs displayed a hydrophilic surface …

The Effects Of Low-Frequency, Low-Intensity Ultrasound On Gene Expression In Macrophage-Endothelial Cell Co-Culture, Evelyn Hergenhan

Honors Theses

Introduction

Low-frequency, low-intensity ultrasound (LFLI US) has been shown to be a promising treatment for noninvasive accelerated chronic wound healing. However, the biological mechanisms of this ultrasound-assisted healing are not yet understood, limiting clinical adoption. The objective of this study is to characterize the effects of LFLI US on gene expression in a simulated chronic wound environment to gain a better understanding of the biological mechanisms underlying this therapeutic.

Methods

A simulated chronic wound environment consisting of endothelial cells and inflammatory M1 macrophages co-cultured in 3D was subject to LFLI US at 50, 100, or 150 mW/cm² Spatial-Peak, Temporal-Peak …

Wearable Biosensors For Continuous Monitoring Of Chronic Kidney Disease: Materials, Biofluids, And Digital Health Integration, Anupamaa Sivasubramanian, Shankara Narayanan, Gymama Slaughter

Center for Bioelectronics Publications

Chronic kidney disease (CKD) is a progressive and irreversible disorder affecting over 850 million individuals globally and is associated with significant morbidity, mortality, and healthcare burden. Conventional diagnostic approaches rely on intermittent laboratory measurements, including serum creatinine, estimated glomerular filtration rate (eGFR), and urinary albumin, which provide limited temporal resolution and fail to capture dynamic physiological changes. Recent advances in wearable biosensing technologies offer new opportunities for continuous, non-invasive monitoring of biochemical and physiological markers relevant to renal function. This review provides a comprehensive analysis of wearable biosensors for CKD monitoring, focusing on sensing mechanisms (electrochemical, optical, and field-effect transistor), …

Work In Progress: The Impact Of Classroom Interventions On Student Success And Retention In Electric Circuits, Cherian Mathews

All Faculty Articles - School of Engineering and Computer Science

University of the Pacific has embarked on a university-wide endeavor to improve student success and retention. This effort involves academic coaches being placed in each unit, early grade reporting in the fifth week of the semester, follow-ups by faculty advisors and academic coaches for struggling students, and documentation of interactions with such students in the university CRM system. These follow-ups with students typically involve conversations to explore factors contributing to poor performance (e.g., health issues, excessive work hours, study skills), suggesting approaches to improve performance, and making referrals to care teams and supplemental instruction. Despite all these efforts, DFW rates …

Stentrx, Emma Barna, Minuthi Cooray, Bruce Newlands, Joseph A. Sabetta

Williams Honors College, Honors Research Projects

This project aims to develop a biodegradable, drug-eluting biliary stent for the treatment of biliary cancers. Current metal stents that restore bile flow bit are non-degradable, prone to migration, and unable to deliver drugs locally. The proposed stent will be biocompatible, biodegradable, and capable of controlled drug release to both maintain bile flow and treat tumors. The end goal is to produce a functional prototype that can be deployed via a minimally invasive catheter and maintain bile duct patency for at least three months. The project is expected to be involved in the NEOMED Bench-to-Bedside competition and provisionally patented.

Metabolic Reprogramming Following Mitochondrial Transfer Between Idh2-Mutant Chondrosarcoma Cells And A Normal B-Cell Line, Caleb Wyckoff, Christopher Osgood, Ellen Jing, Michael Stacey

Bioelectrics Publications

Background/Objectives: Chondrosarcoma, glioblastoma, acute myeloid leukemia, chronic lymphocytic leukemia, and cholangiocarcinoma cancers all contain mutations in the gene isocitrate dehydrogenase 2 (IDH2). The mutant IDH2 enzyme metabolizes alpha-ketoglutarate (αKG) into the potent oncometabolite D-2-hydroxyglutarate (D2HG) in the mitochondria of these cancers, leading to altered cellular metabolism. Emerging evidence suggests that mitochondrial transfer between cancer and recipient cells represents an important form of intercellular communication that may influence cellular metabolism. The presence of intercellular TNTs between IDH2-mutant chondrosarcoma cells motivated an investigation into mitochondria-associated physiological changes occurring during an intercellular exchange with immune cells. A mitochondrial transfer is a two-way …

Determining The Electric Field In A 10 Ns Pulsed Plasma In Fuel-Air Mixtures Using Efish, Md Ziaur Rahman, Christopher J. Kliewer, Brian D. Patterson, Chunqi Jiang

Bioelectrics Publications

Transient plasma ignition (TPI) utilizes non-equilibrium plasmas, produced by nanosecond high-voltage pulses, to improve lean-fuel combustion performance and reduce emission. It is known that the relatively high reduced electric field (E/N) in TPI plays an important role in generating energetic electrons and facilitating energy-efficient radical productions, resulting in reliable ignition for lean combustion. Determining the reduced electric field in the discharge is hence important for the understanding of the TPI process and ultimately allowing for the control of the plasma chemistry. This study reports spatiotemporally resolved measurements of the electric field (E) in a 10 ns pulsed plasma that is …

Establishment And Histopathological Characterization Of A Kyse-30 Subcutaneous Xenograft Model Of Esophageal Squamous Cell Carcinoma, Pavel A. Solopov, Alayna Enos, Mantas Silkunas, Giedre Silkuniene, Eleni Zivla, Andrei G. Pakhomov, Olga N. Pakhomova

Bioelectrics Publications

Background/Objectives: Esophageal squamous cell carcinoma (ESCC) is an aggressive malignancy with poor prognosis and limited treatment options, highlighting the need for reliable preclinical models for translational research. Although xenograft models are widely used in cancer biology, systematic characterization of subcutaneous ESCC models under defined implantation conditions remains limited. The objective of this study was to systematically compare implantation conditions and define histopathological and growth-related parameters that enable reproducible tumor establishment while maintaining a practical experimental window for therapeutic studies. Methods: We established and characterized a subcutaneous ESCC xenograft model using human ESCC cell line KYSE-30 implanted into immunodeficient J:NU mice. …

Combination Therapy With Hsp90 Inhibitors And Nanopulse Stimulation Synergistically Impedes Hepatocellular Carcinoma And Breast Cancer Growth In Mice, Christiana Dimitropoulou, Gagan Thangjam, Brittany P. Lassiter, Teresa Hooker, Ruben M. L. Colunga Biancatelli, John D. Catravas, Stephen J. Beebe

Bioelectrics Publications

Nanopulse Stimulation (NPS) represents a promising and innovative therapeutic approach to cancer. Heat shock protein 90 Inhibitors (HI), on the other hand, are currently under investigation in multi-drug chemotherapy trials for various types of malignancies. Here we present results of a combination therapy employing two HSP90 inhibitors (AUY-922 or 17-AAG) and NPS to ablate cancer growth. We firstly tested the inhibitors alone or in combination with NPS in vitro in N1S1 cells, and then into two models of orthotopic Hepatocellular Carcinoma (HCC) and 4T1-Luc breast cancer. NPS + HI reduced tumor growth more than the sum of HI and NPS …

Influence Of Motion Artifacts On Instantaneous Frequency Based Heart Rate Variability Of Arterial Pulse Signals Measured By A Tactile Sensor: An Analytical Study, Mamun Hasan, Zhili Hao

Mechanical & Aerospace Engineering Faculty Publications

Objective: Heart rate variability (HRV), quantified via the instantaneous frequency (IF) of arterial pulse signals, is a key indicator of cardiovascular (CV) regulation. This study presents a theoretical and experimental investigation of how motion artifacts (MA) influence IF-and thus HRVmeasured with a tactile sensor, emphasizing underlying mechanisms rather than population-level validation. Approach: Building on a previously developed single-degree-of-freedom (SDOF) model of the tissue-contact-sensor (TCS) stack between the sensor and the artery, MA is represented as low-frequency baseline drift and time-varying system parameters (TVSP) of the TCS stack. Analytical expressions quantify the effect of MA on the IF of each harmonic …

Mechanical-Medical Convergence In Heart Failure: Artificial Intelligence, Finite-Element Modeling, And 3d Printing For Diagnosis And Prognosis, Quazi Noor E. Sabrina, Quazi Md Zobaer Shah, Quazi Noor E. Sohela, Md Mahabub Hasan Mousum, Md. Moyeen Uddin Chisty, Quazi Md. Akbar Shah

Mechanical & Aerospace Engineering Faculty Publications

Heart failure remains a leading cause of global morbidity and mortality, yet routine clinical indices often miss the regional biomechanical disturbances that drive progression and shape treatment response. This State-of-the-Art review examines how finite-element (FE) modeling, additive manufacturing, and artificial intelligence (AI) are converging to improve the diagnosis, phenotyping, procedural planning, and prognostic assessment of heart failure (HF). Although these technologies have matured in structural heart disease and transcatheter intervention research, their greatest translational potential may lie in HF, where patient-specific ventricular remodeling, myocardial stress–strain heterogeneity, valve-ventricular coupling, and device-tissue interaction are incompletely captured by conventional clinical indices. We synthesize …

Radical-Based Oxidative Pretreatment Enhances Biofuel Production From Lignocellulosic Biomass Via Hydrothermal Liquefaction, João Vitor Dos Santos, Louis C. Bondurant, Patrick G. Hatcher

Chemistry & Biochemistry Faculty Publications

The sustainable production of biofuels from lignocellulosic biomass is a central goal in the transition to low-carbon energy systems. However, hydrothermal liquefaction (HTL), a promising thermochemical conversion pathway, is constrained by the high oxygen content and complex aromatic structure of lignin, which lowers bio-oil quality. Here, we used a model system of brown-rot-degraded white oak (Quercus alba) to test whether radical-based oxidative pretreatment could enhance HTL performance by converting lignin into more aliphatic intermediates. Oxidation was performed under simulated Fenton conditions using fixed Fe(II) (60 ppm) and two hydrogen peroxide concentrations (3 and 8 M), resulting in extensive lignin depolymerization …

Wip: Arduino-Based Pbl To Foster Entrepreneurial Mindset, Nathan Q. Holland, Vukica M. Jovanovic

Engineering Technology Faculty Publications

This work-in-progress paper examines a semester-long project-based learning initiative begun in an introductory engineering course during the Fall 2025 semester. The project aims to enhance students' hands-on experience by integrating information literacy, the engineering design process (EDP), and an entrepreneurial mindset (EM) [1]. The objective is to boost student confidence in teamwork, technical problem-solving, and application of skills, preparing them for future courses in their discipline. Students in this introduction to engineering course received an Arduino Uno R3 Controller board kit and additional sensors. They were tasked to develop a device addressing engineering in the medicine challenge of their choosing. …

Improving Medical Diagnostics With Vision-Language Models: Convex Hull-Based Uncertainty Analysis, Ferhat Ozgur Catak, Murat Kuzlu, Taylor Patrick, Michel Audette

Engineering Technology Faculty Publications

In recent years, vision-language models (VLMs) have been applied to various fields, including healthcare, education, finance, and manufacturing, with remarkable performance. However, concerns remain regarding VLMs' consistency and uncertainty, particularly in critical applications such as healthcare, which demand a high level of trust and reliability. This paper proposes a novel approach to evaluate uncertainty in VLMs' responses using a convex hull approach on a healthcare application for visual question answering (VQA). For any VLM, temperature refers to a sampling parameter used in probabilistic generation, which controls the randomness of the model's output. The LLM-CXR model is selected as the medical …