Biomedical Engineering and Bioengineering Commons^™

Mechanical And Geometrical Determinants Of Wall Stress In Abdominal Aortic Aneurysms: A Computational Study, Dara Azar, Donya Ohadi, Alexander Rachev, John F. Eberth, Mark J. Uline, Tarek Shazly

Faculty Publications

An aortic aneurysm (AA) is a focal dilatation of the aortic wall. Occurrence of AA rupture is an all too common event that is associated with high levels of patient morbidity and mortality. The decision to surgically intervene prior to AA rupture is made with recognition of significant procedural risks, and is primarily based on the maximal diameter and/or growth rate of the AA. Despite established thresholds for intervention, rupture occurs in a notable subset of patients exhibiting sub-critical maximal diameters and/or growth rates. Therefore, a pressing need remains to identify better predictors of rupture risk and ultimately integrate their …

Evaluation Of Motion Artifact Metrics For Coronary Ct Angiography, Hongfeng Ma, Eric Gros, Aniko Szabo, Scott G. Baginski, Zachary R. Laste, Naveen M. Kulkarni, Darin Okerlund, Tal Gilat Schmidt

Biomedical Engineering Faculty Research and Publications

Purpose

This study quantified the performance of coronary artery motion artifact metrics relative to human observer ratings. Motion artifact metrics have been used as part of motion correction and best‐phase selection algorithms for Coronary Computed Tomography Angiography (CCTA). However, the lack of ground truth makes it difficult to validate how well the metrics quantify the level of motion artifact. This study investigated five motion artifact metrics, including two novel metrics, using a dynamic phantom, clinical CCTA images, and an observer study that provided ground‐truth motion artifact scores from a series of pairwise comparisons.

Method

Five motion artifact metrics were calculated …

Hyperoxia Causes Mitochondrial Fragmentation In Pulmonary Endothelial Cells By Increasing Expression Of Pro-Fission Proteins, Cui Ma, Andreas M. Beyer, Matthew J. Durand, Anne V. Clough, Daling Zhu, Laura Norwood Toro, Maia Terashvili, Johnathan D. Ebben, R. Blake Hill, Said H. Audi, Meetha Medhora, Elizabeth R. Jacobs

Biomedical Engineering Faculty Research and Publications

Objective—We explored mechanisms that alter mitochondrial structure and function in pulmonary endothelial cells (PEC) function after hyperoxia.

Approach and Results—Mitochondrial structures of PECs exposed to hyperoxia or normoxia were visualized and mitochondrial fragmentation quantified. Expression of pro-fission or fusion proteins or autophagy-related proteins were assessed by Western blot. Mitochondrial oxidative state was determined using mito-roGFP. Tetramethylrhodamine methyl ester estimated mitochondrial polarization in treatment groups. The role of mitochondrially derived reactive oxygen species in mt-fragmentation was investigated with mito-TEMPOL and mitochondrial DNA (mtDNA) damage studied by using ENDO III (mt-tat-endonuclease III), a protein that repairs mDNA damage. Drp-1 (dynamin-related …

Raman Spectroscopy Predicts The Link Between Claw Keratin And Bone Collagen Structure In A Rodent Model Of Oestrogen Deficiency, M. Clare Caraher, Antonia Sophocleous, J. Renwick Beattie, Olive O'Driscoll, Niamh M. Cummins, Orlaith Brennan, Fergal J. O'Brien, Stuart H. Ralston, Steven E.J. Bell, Mark R. Towler, Aymen I. Idris

Chemical and Biochemical Engineering Faculty Research & Creative Works

Osteoporosis is a common disease characterized by reduced bone mass and an increased risk of fragility fractures. Low bone mineral density is known to significantly increase the risk of osteoporotic fractures; however, the majority of non-traumatic fractures occur in individuals with a bone mineral density too high to be classified as osteoporotic. Therefore, there is an urgent need to investigate aspects of bone health, other than bone mass, that can predict the risk of fracture. Here, we successfully predicted association between bone collagen and nail keratin in relation to bone loss due to oestrogen deficiency using Raman spectroscopy. Raman signal …

Eigenstrain As A Mechanical Set-Point Of Cells, Shengmao Lin, Marsha C. Lampi, Cynthia A. Reinhart-King, Gary C.P. Tsui, Jian Wang, Carl A. Nelson, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

Cell contraction regulates how cells sense their mechanical environment. We sought to identify the set-point of cell contraction, also referred to as tensional homeostasis. In this work, bovine aortic endothelial cells (BAECs), cultured on substrates with different stiffness, were characterized using traction force microscopy (TFM). Numerical models were developed to provide insights into the mechanics of cell–substrate interactions. Cell contraction was modeled as eigenstrain which could induce isometric cell contraction without external forces. The predicted traction stresses matched well with TFM measurements. Furthermore, our numerical model provided cell stress and displacement maps for inspecting the fundamental regulating mechanism of cell …

Motor Output Variability Impairs Driving Ability In Older Adults: Reply To Stinchcombe, Dickerson, Weaver, And Bedard, Evangelos A. Christou, Basma Yacoubi, Changki Kim, Hwasil Moon, Tanya Onushko, Neha Lodha

Biomedical Engineering Faculty Research and Publications

Driving is a complex skill, as indicated by Stinchcombe and colleagues in their letter. It requires the integration of sensory inputs, cognitive processing, and motor execution. Although our title is broad, we clearly indicate that our findings only address a single component of driving, namely reactive driving. We also indicate that these findings are based on a simulated task and recommend that future studies should examine the contribution of motor output variability to on-road driving performance (see Considerations in the Discussion section). Thus, we share the consideration of Stinchcombe and colleagues that the current results only address a small portion …

Natural Sensations Evoked In Distal Extremities Using Surface Electrical Stimulation, Julia P. Slopsema, John M. Boss, Lane A. Heyboer, Carson M. Tobias, Brooke P. Draggoo, Kathleen E. Finn, Payton J. Hoff, Katharine H. Polasek

Faculty Publications

Background: Electrical stimulation is increasingly relevant in a variety of medical treatments. In this study, surface electrical stimulation was evaluated as a method to non-invasively target a neural function, specifically natural sensation in the distal limbs.

Method: Electrodes were placed over the median and ulnar nerves at the elbow and the common peroneal and lateral sural cutaneous nerves at the knee. Strength-duration curves for sensation were compared between nerves. The location, modality, and intensity of each sensation were also analyzed. In an effort to evoke natural sensations, several patterned waveforms were evaluated.

Results: Distal sensation was obtained in all but …

A Simple Mathematical Model For The Nonlinear Compliance Of Arteries, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Working Papers

No abstract provided.

Identification Of Unique Features And Exploration Of Leap Motion Controller For Detecting Hand Hygiene Stages, Rashmi Bakshi, Jane Courtney, Damon Berry, Graham Gavin

Conference Papers

Hospital acquired infections (HAIs) are contracted by the patients during the hospital stay. Antibiotic resistant microbes are the major cause and spread due to the contaminated medical equipment, crowded hospitals, frequent transfer of patients from one unit to another and poor hand hygiene. [1] In high income countries, approximately 30% of patients in intensive care units are affected by at least one HAI. [2] Hand hygiene is identified as a measure to prevent cross-transmission and to reduce the rate of HAI. [3] Technology is now used as a means of assessing hand hygiene compliance. Current approaches involve the use of …

Optimal Wavelength Selection For Optical Spectroscopy Of Hemoglobin And Water Within A Simulated Light-Scattering Tissue, Mikael Marois, Stephen L. Jacques, Keith D. Paulsen

Dartmouth Scholarship

An algorithm that selects optimal wavelengths for spectral fitting of diffuse light reflectance spectra using a nonnegative least squares method is presented. Oxyhemoglobin, deoxyhemoglobin, and water are considered representative absorbers, but the approach is not constrained or limited by absorber selection provided native basis spectra are available. The method removes wavelengths iteratively from a scattering-modulated absorption matrix by maximizing the product of its singular values and offers considerable improvements over previously published wavelength selection schemes. Resulting wavelength selections are valid for a broad range of optical properties and yield lower RMS errors than other wavelength combinations. The method is easily …

Optimizing Within-Subject Experimental Designs For Jica Of Multi-Channel Erp And Fmri, Jain Mangalathu-Arumana, Einat Liebenthal, Scott A. Beardsley

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Assessing The Validity Of Pressure-Measuring Insoles In Quantifying Gait Variables, Jessica Deberardinis, Janet S. Dufek, Mohamed B. Trabia, Daniel E. Lidstone

Integrated Health Sciences Faculty Research

Introduction Pressure-measuring insoles can provide a portable alternative to existing gait analysis tools. However, there is disagreement among researchers on their accuracy and the appropriate calibration methods. The purposes of this study were to (1) determine the validity of pressure-measuring insoles for calculating stance time and support-phase impulse during walking using two calibration procedures, and (2) examine the effect of insole size on the results. Methods Data were collected from 39 participants (23.5 ± 3.24 yrs, 66.7 ± 17.5 kg, 1.64 ± 0.09 m), each wearing appropriately sized insoles as they walked over two consecutive force platforms. Two calibration methods …

Collective Adhesion And Displacement Of Retinal Progenitor Cells Upon Extracellular Matrix Substrates Of Transplantable Biomaterials, Ankush Thakur, Shawn Mishra, Juan Pena, Jing Zhou, Stephen Redenti, Robert Majeska, Maribel Vazquez

Publications and Research

Strategies to replace retinal photoreceptors lost to damage or disease rely upon the migration of replacement cells transplanted into sub-retinal spaces. A significant obstacle to the advancement of cell transplantation for retinal repair is the limited migration of transplanted cells into host retina. In this work, we examine the adhesion and displacement responses of retinal progenitor cells on extracellular matrix substrates found in retina as well as widely used in the design and preparation of transplantable scaffolds. The data illustrate that retinal progenitor cells exhibit unique adhesive and displacement dynamics in response to poly-l-lysine, fibronectin, laminin, hyaluronic acid, and Matrigel. …

Production Of Genetically Engineered Golden Syrian Hamsters By Pronuclear Injection Of The Crispr/Cas9 Complex, Rong Li, Jinxin Miao, Seokhwan Song, Il-Keun Kong, Yaohe Wang, Zhongde Wang

Animal, Dairy, and Veterinary Science Faculty Publications

The pronuclear (PN) injection technique was first established in mice to introduce foreign genetic materials into the pronuclei of one-cell stage embryos. The introduced genetic material may integrate into the embryonic genome and generate transgenic animals with foreign genetic information following transfer of the injected embryos to foster mothers. Following the success in mice, PN injection has been applied successfully in many other animal species. Recently, PN injection has been successfully employed to introduce reagents with gene-modifying activities, such as the CRISPR/Cas9 system, to achieve site-specific genetic modifications in several laboratory and farm animal species. In addition to mastering the …

Noncontact Three-Dimensional Diffuse Optical Imaging Of Deep Tissue Blood Flow Distribution, Guoqiang Yu, Yu Lin, Chong Huang

Biomedical Engineering Faculty Patents

The present invention provides for three-dimensional reflectance diffuse optical imaging of deep tissue blood flow distribution that removes the need for probe-tissue contact, thereby allowing for such technology to be applied to sensitive, vulnerable, damaged, or reconstructive tissue. The systems utilize noncontact application and detection of near-infrared light through optical lens and detection through a linear array or two-dimensional array of avalanche photodiodes or a two-dimensional array of detectors provided by charge-coupled-device (CCD). Both further feature a finite-element-method (FEM) based facilitation to provide for three-dimensional flow image reconstruction in deep tissues with arbitrary geometries.

Comparison Of Eosin And Fluorescein Conjugates For The Photoinitiation Of Cell-Compatible Polymer Coatings, Jacob L. Lilly, Anuhya Gottipati, Calvin F. Cahall, Mohamed Agoub, Brad J. Berron

Chemical and Materials Engineering Faculty Publications

Targeted photopolymerization is the basis for multiple diagnostic and cell encapsulation technologies. While eosin is used in conjunction with tertiary amines as a water-soluble photoinitiation system, eosin is not widely sold as a conjugate with antibodies and other targeting biomolecules. Here we evaluate the utility of fluorescein-labeled bioconjugates to photopolymerize targeted coatings on live cells. We show that although fluorescein conjugates absorb approximately 50% less light energy than eosin in matched photopolymerization experiments using a 530 nm LED lamp, appreciable polymer thicknesses can still be formed in cell compatible environments with fluorescein photosensitization. At low photoinitiator density, eosin allows more …

Specific Nanoporous Geometries On Anodized Alumina Surfaces Influence Astrocyte Adhesion And Glial Fibrillary Acidic Protein Immunoreactivity Levels, D. Ganguly, C. D.L. Johnson, M. K. Gottipati, D. Rende, D. A. Borca-Tasciuc, R. J. Gilbert

Chemical and Biochemical Engineering Faculty Research & Creative Works

Electrodes implanted in the brain or spinal cord trigger the activation of resident astrocytes. In their reactive state, astrocytes surrounding the electrode form a glial scar, compromising the ability of the electrode to interface with the surrounding neural tissue. One approach to reduce the inhibiting scar tissue is to incorporate nanoarchitecture on the surface of the implanted materials to modify the astrocytic response. The incorporated nanoarchitecture changes both the surface characteristics and the material properties of the implant interface. We investigated the response of rat cortical astrocytes to nanoporous anodic aluminum oxide (AAO) surfaces. Astrocytes were seeded onto nonporous aluminum …

Biomedical Optics Scientific Community, Brian W. Pogue

Dartmouth Scholarship

The new Editor-in-Chief, Brian Pogue, gives an overview of the biomedical optics community.

Low Cost Waist Line Circumference Health Management Belt, Raghav Talreja

Research Opportunities for Engineering Undergraduates (ROEU) Program 2017-18

One third of the American population is obese or near obese, and $150 billion is spent in weight management. Current devices to monitor weight are expensive, and niche products are designed for health enthusiasts. This project investigates user needs, development and commercialization steps for a low cost health management belt.

Preparation For The Study Of Gene Expression Aboard The International Space Station, Amber Paturzo

STAR Program Research Presentations

WetLab-2 performs quantitative polymerase chain reaction (qPCR) aboard the micro-gravity environment of the International Space Station in order to research how the stress of micro-gravity affects an organism’s RNA production and gene expression. This on-station qPCR allows researchers to gather information earlier and thereby allow them to modify experiments in a matter of hours rather than wait until the next flight opportunity. After a successful validation flight on SpaceX-8 and follow-up investigation on SpaceX-9, system components must now be adjusted for a new type of biological sample. Specifically, the WetLab-2 facility includes a commercial qPCR instrument (RNA SmartCycler), a sample …

Machine Learning Provides Predictive Analysis Into Silver Nanoparticle Protein Corona Formation From Physicochemical Properties, Matthew R. Findlay, Daniel N. Freitas, Maryam Mobed-Miremadi, Korin E. Wheeler

Bioengineering

Proteins encountered in biological and environmental systems bind to engineered nanomaterials (ENMs) to form a protein corona (PC) that alters the surface chemistry, reactivity, and fate of the ENMs. Complexities such as the diversity of the PC and variation with ENM properties and reaction conditions make the PC population difficult to predict. Here, we support the development of predictive models for PC populations by relating biophysicochemical characteristics of proteins, ENMs, and solution conditions to PC formation using random forest classification. The resulting model offers a predictive analysis into the population of PC proteins in Ag ENM systems of various ENM …

Modeling Liver Diseases Using Hepatic Cell Microarrays, Alexander David Roth

ETD Archive

Hepatocellular carcinoma (HCC) is an invasive and aggressive cancer of the liver that arises due to chronic cirrhosis. Research into understanding HCC has focused on two-dimensional (2D) and three-dimensional (3D) technologies to simulate the liver microenvironment and use animal models to model how HCC affects the rest of the body. 3D hydrogel models are desired because they can mimic the transport behavior observed in vivo by structurally mimicking the extracellular matrix (ECM) without the ethical concerns of animal models. However, hydrogels can be toxic to cells and require optimal procedures for appropriate handling. In this study, we created 3D models …

Advanced Manufacturing Of Titanium Alloys For Biomedical Applications, Nicholas C. Mavros

ETD Archive

In metallurgy, Titanium has been a staple for biomedical purposes. Its low toxicity and alloying versatility make it an attractive choice for medical applications. However, studies have shown the difference in elastic modulus between Titanium alloys (116 GPa) and human bone (40-60 GPa) contribute to long term issues with loose hardware fixation. Additionally, long term studies have shown elements such as Vanadium and Aluminum, which are commonly used in Ti-6Al-4V biomedical alloys, have been linked to neurodegenerative diseases like Alzheimers and Parkinsons. Alternative metals known to be less toxic are being explored as replacements for alloying elements in Titanium alloys. …

Implementation Of A Reverse Staggered-Herringbone Microfluidic Mixer For High-Throughput Polymeric Nanoparticles Synthesis, Alexa Roberts

Undergraduate Research Posters 2018

The goal of this research is to implement and optimize the operating conditions of a microfluidic mixer to synthesize polymeric nanoparticles (NPs) in a high-throughput fashion. Using a reverse staggered-herringbone microfluidic mixer that we recently designed, the effects of experimental conditions such as flowrate and reactant composition on NP characteristics were investigated and optimized. The device design allowed for physical contact between two streams of fluids – one containing poly(lactic-co-glycolic acid; PLGA) in acetonitrile and the other deionized water, to allow for efficient mixing and NP precipitation to occur. The resulting NPs were characterized using dynamic light scattering (DLS) and …

Prediction Of Metabolism-Induced Neurotoxicity On A 384pillarplate, Rushabh Patel, Pranav Joshi, Soo-Yeon Kang, Stephen Hong, Parnian Bigdelou

Undergraduate Research Posters 2018

Metabolism of compounds including neurotoxins primarily occurs in the liver by a variety of drug-metabolizing enzymes (DMEs) followed by a series of downstream responses. Unmodified (or parent) neurotoxins are transported into human hepatocytes through several influx transporters or via passive diffusion and undergo Phase I and Phase II biotransformation by DMEs before they are cleared. Neurotoxins and their metabolites generated from human hepatocytes could potentially lead to the toxic effects on neural stem cells (NSCs) as the reactive metabolites have potential for producing reactive oxygen species (ROS), which can lead to irreversible oxidative damage to NSCs via lipid peroxidation, DNA, …

Dendrite Morphology Of Pb-5.8 Sb Alloy: Gradient Freeze Ds With Cross-Section Area Change, Michael Shannon

Undergraduate Research Posters 2018

Directional solidification (DS) is the process of solidifying a metal alloy from one end to another resulting in aligned primary dendrites which are branched tree like features. Alignment of primary dendrites along [100] direction and their uniformity and distribution along the DS length determines the mechanical properties. These properties are especially important for single crystal turbine blade applications in modern gas turbine engines. Convection during solidification plays an important role in formation of detrimental defects, such as, misaligned grains, non-uniformity of dendrites and composition inhomogeneity. In this study the microstructural evolution during “Gradient Freeze DS process”, involving an abrupt cross-section …

Optimization Of Wavelength Selection For Multispectral Image Acquisition: A Case Study Of Atrial Ablation Lesions, Huda Asfour, S. Guan, Narine Muselimyan, Luther M. Swift, Murray Loew, Narine Sarvazyan

Pharmacology and Physiology Faculty Publications

In vivo autofluorescence hyperspectral imaging of moving objects can be challenging due to motion artifacts and to the limited amount of acquired photons. To address both limitations, we selectively reduced the number of spectral bands while maintaining accurate target identification. Several downsampling approaches were applied to data obtained from the atrial tissue of adult pigs with sites of radiofrequency ablation lesions. Standard image qualifiers such as the mean square error, the peak signal-to-noise ratio, the structural similarity index map, and an accuracy index of lesion component images were used to quantify the effects of spectral binning, an increased spectral distance …

Analytical Cpg Model Driven By Limb Velocity Input Generates Accurate Temporal Locomotor Dynamics, Sergiy Yakovenko, Anton Sobinov, Valeriya Gritsenko

Faculty & Staff Scholarship

The ability of vertebrates to generate rhythm within their spinal neural networks is essential for walking, running, and other rhythmic behaviors. The central pattern generator (CPG) network responsible for these behaviors is well-characterized with experimental and theoretical studies, and it can be formulated as a nonlinear dynam- ical system. The underlying mechanism responsible for locomotor behavior can be expressed as the process of leaky integration with resetting states generating appropriate phases for changing body velocity. The low-dimensional input to the CPG model generates the bilateral pattern of swing and stance modulation for each limb and is consistent with the desired …

Effects Of Water Content And Particle Size On Yield And Reactivity Of Lignite Chars Derived From Pyrolysis And Gasification, Yong Huang, Yonggang Wang, Hao Zhou, Yaxuan Gao, Deliang Xu, Lei Bai, Shu Zhang

Faculty & Staff Scholarship

Water inside coal particles could potentially enhance the interior char–steam reactions during pyrolysis and gasification. This study aims to examine the effects of water contents on the char conversion during the pyrolysis and gasification of Shengli lignite. The ex-situ reactivities of chars were further analyzed by a thermo gravimetric analyzer (TGA). Under the pyrolysis condition, the increase in water contents has monotonically decreased the char yields only when the coal particles were small (μm). In contrast, the water in only large coal particles (0.9–2.0 mm) has clearly favored the increase in char conversion during the gasification condition where 50% steam …

Quantum Confined Peptide Assemblies With Tunable Visible To Near-Infrared Spectral Range, Kai Tao, Zhen Fan, Leming Sun, Pandeeswar Makam, Zhen Tian, Mark Ruegsegger, Shira Shaham-Niv, Derek Hansford, Ruth Aizen, Zui Pan, Scott Galster, Jianjie Ma, Fan Yuan, Mingsu Si, Songnan Qu, Mingjun Zhang, Ehud Gazit, Junbai Li

Faculty & Staff Scholarship

Quantum confined materials have been extensively studied for photoluminescent applica- tions. Due to intrinsic limitations of low biocompatibility and challenging modulation, the utilization of conventional inorganic quantum confined photoluminescent materials in bio- imaging and bio-machine interface faces critical restrictions. Here, we present aromatic cyclo-dipeptides that dimerize into quantum dots, which serve as building blocks to further self-assemble into quantum confined supramolecular structures with diverse morphologies and photoluminescence properties. Especially, the emission can be tuned from the visible region to the near-infrared region (420 nm to 820 nm) by modulating the self-assembly process. Moreover, no obvious cytotoxic effect is observed for …