Cell Imaging And Data Analysis For Biomaterial-Mammalian Co-Cultures, Jefferson Pontsler

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Microscopic bioimaging is a useful approach to study cell-biomaterial interactions which are vital to the biomedical application of biomaterials. Through microscopic imaging, numerous cellular responses, such as proliferation, uptake, and death, can be recorded, characterized and analyzed.

In this thesis, I first provided basic introductions to the imaging techniques and analysis tools, especially those that are highly relevant to the studies of biomaterials and cell interactions. I also detailed the adaptation of these techniques and tools in the application of two specific research projects in biomaterials, with special focuses on the imaging and analysis.

The first project assessed the subtle …

Effect Of Physical Stimuli On Angiogenic Factor Expression In Retinal Pigment Epithelial Cells, Farhad Farjood

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Age-related macular degeneration (AMD) is a major cause of blindness in adults. Abnormal growth of blood vessels in the eye during the course of AMD causes damage to the retina, resulting in irreversible blindness. The goal of this research was to determine whether physical pressure on retinal cells can contribute to the increased blood vessel formation. To replicate the tears in the cell layers, a micropatterning method was used as a means of detaching cells from each other. Two new devices were also developed to mimic slow and fast increases in mechanical pressure on cell layers of the eye. After …

In Vitro Simulation Of Microgravity Induced Muscle Loss Successfully Increases Expression Of Key In Vivo Atrophy Markers, Charles P. Harding

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Muscle loss from lack of activity is a serious issue for immobilized patients on Earth and in human spaceflight, where the low gravity environment prevents normal muscle activity. Simulating muscle loss in cultured cells is an important step in understanding how this condition occurs. This work evaluates different means of simulating muscle loss and selects the one that most closely mimics the cellular responses seen in animals and humans.

To simulate the microgravity environment of spaceflight, mouse skeletal muscle cells were grown in a rotary cell culture system (RCCS). Growing the cells within a natural gelled substrate was compared against …

The Development Of A Viscoelastic Ellipsoidal Model For Use In Measuring Plantar Tissue Material Properties During Walking, Jessica Lee Deberardinis

UNLV Theses, Dissertations, Professional Papers, and Capstones

Introduction: The mechanical characteristics of the plantar tissues during walking is not well understood as most of the current research focuses on testing specific plantar regions in cadavers or while the feet of the participants are raised. In this work, it is hypothesized that a viscoelastic geometric ellipsoid model used to assess multiple structures of the foot would be accurate and robust. This model would be participant-specific and applicable to the entire stance phase of gait.

Methods: The proposed viscoelastic ellipsoid model would represent several key anatomical areas: Heel, Posterior Midfoot, Anterior Midfoot, Metatarsals 1-2, Metatarsals 3-5, Toe 1, Toe …

Using Peripheral Venous Pressure Waveforms To Predict Key Hemodynamic Parameters, Ali Zohair A Alalawi

Graduate Theses and Dissertations

Analysis of peripheral venous pressure (PVP) waveforms is a novel method of monitoring intravascular volume. Two cohorts were used to study the hemodynamics change of the body state and its influence on the PVP using (1) dehydration setting with infants suffering from pyloric stenosis and (2) hemorrhage setting during a craniosynostosis elective surgery. The goal of this research is to develop a minimally invasive method of analyzing the PVP waveforms and find correlations with volume loss.

Twenty-three pyloric stenosis patients PVP were acquired at five stages and were divided into euvolemic, normal fluid volume, and hypovolemic, significant fluid loss. Seven …

Diffuse Reflectance Spectroscopy To Quantify In Vivo Tissue Optical Properties: Applications In Human Epithelium And Subcutaneous Murine Colon Cancer, Gage Joseph Greening

Graduate Theses and Dissertations

Colorectal cancer is the 4th most common and 2nd deadliest cancer. Problems exist with predicting which patients will respond best to certain therapy regimens. Diffuse reflectance spectroscopy has been suggested as a candidate to optically monitor a patient’s early response to therapy and has been received favorably in experimentally managing other cancers such as breast and skin. In this dissertation, two diffuse reflectance spectroscopy probes were designed: one with a combined high-resolution microendoscopy modality, and one that was optimized for acquiring data from subcutaneous murine tumors. For both probes, percent errors for estimating tissue optical properties (reduced scattering coefficient and …

Volumetric Muscle Loss: The Role Of Physical Activity And Autologous Repair On Force Recovery And Signaling Pathways, Richard Perry

Graduate Theses and Dissertations

Volumetric muscle loss affects both military and civilian persons. The hallmark of this injury is incomplete muscle regeneration, excessive fibrosis, and chronic inflammatory signaling resulting in permanent functional loss. Since permanent functional loss drastically reduces quality of life, many studies have been conducted to improve force recovery. Current scientific literature considers a repair strategy of either devitalized scaffolds infused with growth factors or viable tissue plus activating factors to be the more promising interventions for optimal force recovery. PURPOSE The purpose of this study is to incorporate autologous repair and physical activity and observe the effects of muscle force recovery …

Role Of Local Renin-Angiotensin System In Potentiating Early Calcific Aortic Valve Disease, Jessica Perez

Graduate Theses and Dissertations

Angiotensin-II (Ang-II), a peptide hormone, is a potent vasoconstrictor and cell mitogen. It has been implicated in the development of hypertension as well as atherosclerosis. Recent work has shown that sclerotic aortic valves possess expression of angiotensin type I receptor (AT-1R) and angiotensin converting enzyme (ACE), suggesting altered angiotensin signaling during disease. The role of altered angiotensin signaling on aortic valve mechanics, however, is not clearly understood. We seek to understand the direct effects of the renin angiotensin signaling (RAS) system on the biological and biomechanical properties of aortic valve tissue and develop a finite constitutive model that mimics the …

Feedforward And Feedback Signals In The Olfactory System, Srimoy Chakraborty

Graduate Theses and Dissertations

The conglomeration of myriad activities in neural systems often results in prominent oscillations. The primary goal of the research presented in this thesis was to study effects of sensory stimulus on the olfactory system of rats, focusing on the olfactory bulb (OB) and the anterior piriform cortex (aPC). Extracellular electrophysiological measurements revealed distinct frequency bands of oscillations in OB and aPC. However, how these oscillatory fluctuations help the animal to process sensory input is not clearly understood. Here we show high frequency oscillations in olfactory bulb carry feedforward signals to anterior piriform cortex whereas feedback from the aPC is predominantly …

Biomedical Engineering Or Biomedical Optics: Will The Real Discipline Please Stand Up?, Brian W. Pogue

Dartmouth Scholarship

This editorial reflects on the shape of biomedical engineering as a discipline, and its relation to biomedical optics.

Brain Image Clustering By Wavelet Energy And Cbsso Optimization Algorithm, Hasan Hosseinzadeh, Mohammad Sedaghat

Journal of Mind and Medical Sciences

Previously, the diagnosis of brain abnormality was significantly important in the saving of social and hospital resources. Wavelet energy is known as an effective feature detection which has great efficiency in different utilities. This paper suggests a new method based on wavelet energy to automatically classify magnetic resonance imaging (MRI) brain images into two groups (normal and abnormal), utilizing support vector machine (SVM) classification based on chaotic binary shark smell optimization (CBSSO) to optimize the SVM weights.

The results of the suggested CBSSO-based KSVM are compared favorably to several other methods in terms of better sensitivity and authenticity. The proposed …

Cold Plasma Poration And Corrugation Of Pumpkin Seed Coats, Alexander G. Volkov, Jewel S. Hairston, Darayas Patel, Ryan P. Gott, Kunning G. Xu

PRC-Affiliated Research

The treatment of seeds and plants by electrically generated cold atmospheric pressure plasma can accelerate seed germination and radicle growing rates. The plasma generated reactive oxygen and nitrogen species, UV photons, and high frequency electromagnetic fields can penetrate into seed coats and modify their surface properties. Atomic force microscope data shows that cold helium or argon plasma induces strong corrugation of pumpkin seed coats, produces pores and surface defects. These structural deformations and poration enhance water uptake by seeds during the imbibing process, accelerate seeds germination, and increase seed growth. The cold atmospheric pressure plasmas treatment of pumpkin seeds also …

Cold Plasma Poration And Corrugation Of Pumpkin Seed Coats, Alexander G. Volkov, Jewel S. Hairston, Darayas Patel, Ryan P. Gott, Kunning G. Xu

PRC-Affiliated Research

The treatment of seeds and plants by electrically generated cold atmospheric pressure plasma can accelerate seed germination and radicle growing rates. The plasma generated reactive oxygen and nitrogen species, UV photons, and high frequency electromagnetic fields can penetrate into seed coats and modify their surface properties. Atomic force microscope data shows that cold helium or argon plasma induces strong corrugation of pumpkin seed coats, produces pores and surface defects. These structural deformations and poration enhance water uptake by seeds during the imbibing process, accelerate seeds germination, and increase seed growth. The cold atmospheric pressure plasmas treatment of pumpkin seeds also …

Cold Plasma Poration And Corrugation Of Pumpkin Seed Coats, Alexander G. Volkov, Jewel S. Hairston, Darayas Patel, Ryan P. Gott, Kunning G. Xu

PRC-Affiliated Research

The treatment of seeds and plants by electrically generated cold atmospheric pressure plasma can accelerate seed germination and radicle growing rates. The plasma generated reactive oxygen and nitrogen species, UV photons, and high frequency electromagnetic fields can penetrate into seed coats and modify their surface properties. Atomic force microscope data shows that cold helium or argon plasma induces strong corrugation of pumpkin seed coats, produces pores and surface defects. These structural deformations and poration enhance water uptake by seeds during the imbibing process, accelerate seeds germination, and increase seed growth. The cold atmospheric pressure plasmas treatment of pumpkin seeds also …

The Modeling, Design, Fabrication, And Application Of Biosensor Based On Electric Cell-Substrate Impedance Sensing (Ecis) Technique In Environmental Monitoring, Xudong Zhang, William Wang, Sunghoon Jang

Publications and Research

In this research, the modeling, design, fabrication, and application of ECIS sensors in environmental monitoringare studied. The ECIS sensors are able to qualify the water toxicity through measuring the cell impedance. A novel mathematical model is proposed to analyze the distribution of electric potential and current of ECIS. This mathematical model is validated by experimental data and can be used to optimize the dimension of ECIS electrodes in order to satisfy environmental monitors. The detection sensitivity of ECIS sensors is analyzed by the mathematical model and experimental data. The simulated and experimental results show that ECIS sensors with smaller radius …

An Arm And A Leg: Medtech Perspectives On Human-Centered Design, Evan D. Poff

Marriott Student Review

The art of human-centered design accounts for both technological and emotional specifications in order to deliver meaningful products that meet the specific needs of the individual customer. Every business professional can deepen his or her understanding of human-centered design – regardless of our industry of choice – by looking to perspectives that the business of medical technology offers. To that end, this article draws upon interviews with three figures in this remarkable field, distilling their insights on how to cultivate businesses that produce human-centered solutions.

Stabilized Interleukin-4-Loaded Poly(Lactic- Co-Glycolic) Acid Films Shift Proinflammatory Macrophages Toward A Regenerative Phenotype In Vitro, Alexis M. Ziemba, Anthony R. D'Amato, Taylor M. Macewen, Devan L. Puhl, Abigail N. Koppes, Ryan A. Koppes, Michelle R. Lennartz, Ryan J. Gilbert

Chemical and Biochemical Engineering Faculty Research & Creative Works

Macrophages are immune cells involved in wound healing and tissue regeneration; however, the sustained presence of proinflammatory macrophages in wound sites impairs healing. In this study, we shifted peritoneal macrophage polarization away from a proinflammatory (M1) phenotype through exposure to stabilized interleukin-4 (IL-4) in poly (lactic-co-glycolic acid) films in combination with topographical guidance from electro spun poly-l-lactic acid fibers. To our knowledge, this was the first study to stabilize IL-4 with bovine serum albumin (BSA) within a biomaterial. When IL-4 was coloaded with BSA for stabilization, we saw increased IL-4 bioactivity compared to no added stabilization, trehalose stabilization, or murine …

Developing A Synthetic Model Of The Candida Albicans Cell Wall Using Self-Assembled Monolayers To Host Beta-Glucan As Ligands, Ushnik Ghosh

Biomedical Engineering ETDs

The goal of this investigation is to study mechanisms the immune cell receptor, Dectin-1, uses to identify the fungal cell species, Candida albicans. Dectin-1 identifies extracellular matrix polysaccharides that Candida albicans express known as β-glucan. To study the interaction of β-glucan – Dectin-1 at the nanoscopic scale, the investigators of this project have endeavored to model the Candida albicans cell wall with engineered Self-Assembled Monolayers presenting β-glucan as a ligand for immobilized Dectin-1 receptors. By engineering a simplified ex-vivo model of the Candida albicans cell wall, the investigators of this study aim to gain precise control of the composition …

Incorporation Of Egfr And Ron Receptors Into Nanodiscs, Cristina Flores-Cadengo

Biomedical Engineering ETDs

Understanding the structure-function relationship of membrane receptors is essential to comprehend the crosstalk between key signaling pathways. Aberrant trans-activation between receptors can lead to tumorigenesis. Two of these receptors known to be involved in cancer development are receptor tyrosine kinases (RTKs), RON (Recepteur d'Origine Nantais) and EGFR (Epidermal Growth Factor Receptor). There has been evidence of heterodimerization and crosstalk between these two receptors based on co-immunoprecipitation, however the structural requirements behind these interactions remain unknown. Structural studies could provide insights into these RTKs’ modes of dimerization and structure-function relationship. However, structural studies of full-length membrane proteins are often difficult due …

Use Of Surface-Enhanced Raman Scattering (Sers) Probes To Detect Fatty Acid Receptor Activity In A Microfluidic Device, Han Zhang, Wei Zhang, Lifu Xiao, Yan Liu, Timothy A. Gilbertson, Anhong Zhou

Biological Engineering Faculty Publications

In this study, 4-mercaptobenzoic acid (MBA)-Au nanorods conjugated with a GPR120 antibody were developed as a highly sensitive surface-enhanced Raman spectroscopy (SERS) probe, and were applied to detect the interaction of fatty acids (FA) and their cognate receptor, GPR120, on the surface of human embryonic kidney cells (HEK293-GPRR120) cultured in a polydimethylsiloxane (PDMS) microfluidic device. Importantly, the two dominant characteristic SERS peaks of the Raman reporter molecule MBA, 1078 cm⁻¹ and 1581 cm⁻¹, do not overlap with the main Raman peaks from the PDMS substrate when the appropriate spectral scanning range is selected, which effectively avoided the …

Improved Production Of Antifungal Angucycline Sch47554 By Manipulating Three Regulatory Genes In Streptomyces Sp. Scc-2136, Ozkan Fidan, Riming Yan, Du Zhu, Jixun Zhan

Biological Engineering Faculty Publications

Sch47554 and Sch47555 are two angucyclines with antifungal activities against various yeasts and dermatophytes from Streptomyces sp. SCC‐2136. The schgene cluster contains several putative regulatory genes. Both schA4 and schA21were predicted as the TetR family transcriptional regulators, whereas schA16shared significant similarity to the AraC family transcriptional regulators. Although Sch47554 is the major product of Streptomyces sp. SCC‐2136, its titer is only 6.72 mg/L. This work aimed to increase the production of this promising antifungal compound by investigating and manipulating the regulatory genes in the Sch47554 biosynthetic pathway. Disruption of schA4and schA16 led to a significant increase …

Fluoride Removal From Water Using A 3d Printed Calcium Carbonate Filter, Sophia Bakar, David Kahler, Benjamin S. Goldschmidt

Undergraduate Research and Scholarship Symposium

Groundwater containing high concentrations of fluoride is the most common source of drinking water in rural areas in parts of east Africa, India, and China. The elevated levels of fluoride cause skeletal and dental fluorosis, which is the weakening and decay of bone structures due to the leeching of calcium from the body as calcium and fluoride bond by the process of adsorption. Over 150 million people are suffering from some form of fluorosis due to the consumption of groundwater. Calcium carbonate has been demonstrated to influence fluoride removal in several forms. To make fluoride removal a cost-effective and user-friendly …

Quantifying Iron Overload Using Mri, Active Contours, And Convolutional Neural Networks, Andrea Sajewski, Stacey Levine

Undergraduate Research and Scholarship Symposium

Iron overload, a complication of repeated blood transfusions, can cause tissue damage and organ failure. The body has no regulatory mechanism to excrete excess iron, so iron overload must be closely monitored to guide therapy and measure treatment response. The concentration of iron in the liver is a reliable marker for total body iron content and is now measured noninvasively with magnetic resonance imaging (MRI). MRI produces a diagnostic image by measuring the signals emitted from the body in the presence of a constant magnetic field and radiofrequency pulses. At each pixel, the signal decay constant, T2*, can be calculated, …

Novel Calibrated Short Tr Recovery (Castrr) Method For Brain-Blood Partition Coefficient Correction Enhances Gray-White Matter Contrast In Blood Flow Measurements In Mice, Scott W. Thalman, David K. Powell, Ai-Ling Lin

Biomedical Engineering Faculty Publications

The goal of the study was to develop a novel, rapid Calibrated Short TR Recovery (CaSTRR) method to measure the brain-blood partition coefficient (BBPC) in mice. The BBPC is necessary for quantifying cerebral blood flow (CBF) using tracer-based techniques like arterial spin labeling (ASL), but previous techniques required prohibitively long acquisition times so a constant BBPC equal to 0.9 mL/g is typically used regardless of studied species, condition, or disease. An accelerated method of BBPC correction could improve regional specificity in CBF maps particularly in white matter. Male C57Bl/6N mice (n = 8) were scanned at 7T using CaSTRR …

Kinematics During Knee Extension, Lunge, And Chair Rise, Center For Orthopaedic Biomechanics, Kevin Shelburne, Phd, Michael D. Harris, Phd, Vasiliki Kefala, Donald R. Hume, Bradley S. Davidson, A. J. Cyr, R. H. Kim, A. A. Ali, E. M. Mannen

Living Kinematics of the Knee

No abstract provided.

Automated Atrial Fibrillation Detection From Electrocardiogram, Senbao Lu

Bioengineering Master's Theses

In this study, a novel Atrial Fibrillation (AFib) detection algorithm is presented based on Electrocardiography (ECG) signals. In particular, the spectrogram of ECG signal is used as an input to a Convolutional Neural Network (CNN) to classify normal and AFib ECG signals. This model is shown to perform well with an accuracy of 92.91% and a value of 0.9789 for the area under the ROC curve (AUC). This study demonstrated the potential of using image classification methods and CNN model to detect abnormal biosignals with noise.

Suture-Less Trocar Site Closure Clip, Hares A. Patel

Electronic Theses and Dissertations

Introduction: Following laparoscopic surgery, there is a need, in many cases, to close trocar sites to prevent hernias. Currently, devices that exist on the market are suture based, but the lack of standardization in the suturing techniques together with the time-consuming nature of the procedure leads to the need for improvement in trocar site closure products. Trocar closure sites do not need to be fully closed on the fascial layer; rather, sufficiently blocking the hole at the abdominal wall can significantly reduce post-operative herniation. A retrospective study on trocar site herniation (TSH) after laparoscopic surgery indicates a TSH incidence …

Soft Palate Modification Using A Collagen Crosslinking Reagent For Equine Dorsal Displacement Of The Soft Palate And Other Upper Airway Breathing Disorders, Stephanie Hunt, Jonathan Kuo, Fabio A Aristizabal, Matt Brown, Abhijit R. Patwardhan, Thomas Hedman

Biomedical Engineering Faculty Publications

The mechanical properties of the soft palate can be associated with breathing abnormalities. Dorsal displacement of the soft palate (DDSP) is a naturally occurring equine soft palate disorder caused by displacement of the caudal edge of the soft palate. Snoring and a more serious, sometimes life-threatening, condition called obstructive sleep apnea (OSA) are forms of sleep-related breathing disorders in humans which may involve the soft palate. The goal of this study was to investigate the effect of injecting the protein crosslinker genipin into the soft palate to modify its mechanical properties for the treatment of equine DDSP with potential implications …

Primitive Palms: A Density Study On The Impacts Of Harvesting Natural Materials For Construction Purposes On Sumak Allpa Of The Amazon Rainforest, Zachary Bull

Independent Study Project (ISP) Collection

In an effort to better understand how rural construction techniques affect a surrounding environment, this study combines a density test of the natural building materials used in the construction of a school on Sumak Allpa island of the Orellana Province in the Amazon basin of Ecuador. The focus of the study measures the density of the bamboo species Guadua angustifolia and the Panama hat plant Carludovica palmata on the island while noting a comprehensive compilation of the techniques and materials used in the building process. Using a mix of plots and transects, a comparison of harvested material to remaining material …

3d-Printed Culture Plate Insert With Agarose Barrier For The Evaluation Of Stem-Cancer Cell Signaling., Erika M. Lewis

Honors Capstones

No abstract provided.