UofM Honors Students Present Research at Posters at the Capitol
A group of University of Memphis students presented their research to state legislators and the public at the Tennessee State Capitol in Nashville on February 14, 2024. The University of Memphis cohort joined undergraduates from public universities across the state to participate in the event that also included lunch and a short address from Gov. Bill Lee. The Posters at the Capitol event helps to increase understanding of the importance of undergraduate research in the education of our students. The students selected for this prestigious event represent the best of undergraduate research in STEM disciplines at their own institutions.
UofM Participants
Alexandra Snyder
Mechanical Characterization of Near Field Electrospun Fiber Alignment Angles for Bioresorbable Vascular Grafts
Faculty Mentor: Dr. Gary Bowlin
Abstract: Cardiovascular disease, characterized by the thickening of blood vessels, is the leading cause of death worldwide. Treatments involve surgical implementation of either autologous or synthetic grafts to replace the diseased tissues. The goal of this experiment was to create a synthetic graft that could maintain its integrity long-term through tissue regeneration. Polydioxanone templates with fiber alignment angles of 15°/75° and 30°/60° were created using a custom built near-field electrospinner. Mechanical properties of the different angles were compared to the saphenous vein (SV) and internal mammary artery (IMA) through longitudinal and circumferential uniaxial mechanical testing, suture retention, and burst pressure. The results of the mechanical testing presented the 15°/75° templates as the closest to the native vessel target values compared to the 30°/60°; however, neither of the templates met all the target values. In ultimate tensile strength, all angles met the SV value on the circumferential axis (2.61 MPa) and the IMA value on the longitudinal axis (4.3 MPa). In suture retention, the 15°/75° template was the only angle in the IMA and SV target range (138-200 gf). Finally, the burst pressure test showed that neither of the templates were in range of the SV or IMA values (1600-3196 mmHg).
Alexandria Kerr
Hollow Hair in Bears: Historic Hybridization and Transfer of an Adaptive Trait
Faculty Mentor: Dr. Emily Puckett
Abstract: Polar bears (Ursus maritimus) have numerous adaptations for living in the Arctic environment. A particularly enigmatic adaptation is that their fur is “hollow” and filled with air. Moreover, there are protrusions from this hollow area that extend through the cortex, referred to as “air pockets”. Studies of the evolutionary history between polar and brown bears (U. arctos) show unidirectional gene flow from polar bears into brown bears. In Southeast (SE) Alaska, the proportion of polar bear ancestry in brown bears ranges from 5-8%. We discovered the hollow hair trait in the SE Alaskan brown bears, and hypothesize it occurs due to introgression from polar bears. Using a collection of 206 individual brown bears, we characterized the trait by examining individual hairs (n=3) under compound microscopy. We measured the length of individual hairs with either the wildtype (i.e., normal) or hollow trait, then calculated proportions along the hair. Within the SE Alaskan population, 33% of animals had the mutant hollow hair trait. We are using population genomics to identify shared introgressed genomic segments among brown bears with the hollow hair phenotype. Our work will enable an investigation into how adaptive traits may become deleterious due to changing climatic conditions over time.
Calvin Robinson
Examination of the Role of MAPK Activity on Placental Formation in Vitro Using Stem Cells
Faculty Mentor: Dr. Amy Abell
Abstract: Mitogen-activated protein kinase kinase kinase 4 (MAP3K4) phosphorylates and activates several MAP2K (mitogen-activated protein kinase kinase) enzymes, including MAP2K3, MAP2K4, MAP2K6, and MAP2K7. Upon activation, MAP2K3/6 phosphorylate p38, MAP2K4/7 phosphorylate JNK, and MAP2K1/2 phosphorylate ERK. We hypothesized that the activation of these enzymes promotes placental and fetal maturation, prompting examination of these pathways. This study investigated wild-type and MAP3K4 kinase-inactive mouse cells in vitro in multiple biologically independent experiments. Trophoblast stem (TS) cells were treated with either DMSO (-) or 3 µM of CHIR 99021 for 96 hours. We measured the activity of p38, JNK, and ERK using polyacrylamide gel electrophoresis and Western blotting. We found that the p38 and JNK mitogen-activated protein kinase (MAPK) pathways were induced during differentiation of wild-type TS cells to SynT-II cells. In contrast, activation of the ERK MAPK pathway was reduced upon differentiation. MAP3K4 kinase inactivation resulted in a failure to activate JNK or p38 MAPKs and the inability to form SynT-II cells. Together, these data suggest a key role for MAP3K4 activation of JNK and p38 in the formation of the SynT-II cells of the placenta. Future studies will assess the activation of MAPK signaling in vivo during placental development.
David Adaway
Using ImageJ to Improve Fluorescence Microscopy Images
Faculty Mentor: Dr. Chrysanthe Preza
Abstract: We use microscopy to make the invisible visible – that is, to see great detail in tiny three-dimensional objects. However, the process of capturing images from a microscope is imperfect; the lens is often unable to focus on the entirety of a three-dimensional volume, causing blurred output. This project provides a solution to the issue: it uses ImageJ, a scientific image-processing software program, to obtain a restored final image from the raw data. Its various functions and plugins were used to process data and conduct simulations. First, the RandomJ plugin adds various types of noise to simulate the blurry output from a microscope. We created a macro that uses the built-in Crop function to split images into smaller pieces, which minimizes the computational resources required to process them. The DeconvolutionLab2 plugin takes a blurred image and a microscope’s point-spread function as input and attempts to output the original image. We tested various plugins for noise mitigation and compared the outputs by calculating the mean squared error. Finally, the MosiacJ plugin stitches the cropped pieces back together. With these tools, we replicated and reversed the microscopic imaging process, and we obtained an output image that better resembles the underlying subject.
Madiha Syeda
Fabrication and Characterizations of Aluminum Doped Cadmium Oxide (CD0: Al) Thin Film Using Sol-Gel Spin-Coating Method
Faculty Mentor: Dr. Monirruzaman Syed
Abstract: Aluminum-doped Cadmium Oxide (CdO: Al) thin films are deposited on quartz silica substrates by the sol-gel spin-coating method as a function of the spin coater’s rpm (revolution per minute). Cadmium Acetate Dihydrate and Aluminum Nitrate have been taken as the precursor materials and a source of Al-dopant respectively. CdO:Al thin films are characterized by X-Ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive Spectroscopy (SEM-EDX), Ramen Scattering, Fourier Transform Infrared (FT/IR), XRD result indicates the highest crystallinity at 6000 rpm with a crystallite size of approximately 31.845 nm, cubic phase formation, and strain of ~1.6 X10^-2. FE-SEM/SEM/EDX shows the well-faceted homogeneous surface structure at 6000 rpm having an average particle size of 130.05 nm. Ramen Scattering results show strong peaks at ~933-935 cm^-1, indicating the presence of CdO:Al. The peak intensity strengthens with increasing rpm. FT/IR also confirms the presence of CdO:Al in the film with the peak position shifting to higher wavenumbers respective to increasing rpm.
Omar Alyousef
Printed Electrode on Soft Materials for Wearable Electronic Devices
Faculty Mentor: Dr. Yuan Gao
Abstract: Electrodes fabricated on soft polymeric substrates, namely smart wearables, are of great importance in a wide range of applications in healthcare monitoring due to their lightweight nature, biocompatibility, and ability to conform to curvilinear body shape. Among available electrode fabrication techniques, inkjet printing is a digital, mask-free, material-saving, and fast fabrication technology. This project investigates the fabrication of printing silver nanoparticles (AgNPs) on a soft, thin film substrate, Polydimethylsiloxane (PDMS), using inkjet printing method. The objective is to create a piezoresistive soft material that will have a wide range of applications. The PDMS is spin-coated to create a thin film and then chemically treated to induce hydrophilicity which enhances the compatibility of the material with the AgNPs. An inkjet printer then precisely deposits the AgNPs onto the thin film PDMS substrate. The printed electrode is used to efficiently conduct electrode signals. One practical application of this printed thin film materials is to measure the applied pressure by the change of the electrode’s resistance due to strain through the materials, which opens a multitude of possibilities for monitoring and detecting various physical interactions and forces. The simple electrode fabrication process and adaptable nature of the thin film holds promise for many applications, particularly in the domains of wearable electronics, soft robotics, and smart devices.
Zaid Hadidi
Improving the Construction of QM Cluster Modeling using FSAPT Interaction Energies
Faculty Mentor: Dr. Nathan DeYonker
Abstract: A fundamental part of drug discovery is understanding the mechanism of enzyme-substrate interactions. One focus of the DeYonker lab is the design and application of computational enzymology, specifically using Quantum Mechanical-cluster models. My project utilizes the chorismate mutase enzyme as a case study and extends the results of qualitative contact-based Residue Interaction Networks (RINs) with quantitative interaction energies from functional group symmetry adapted perturbation theory (F-SAPT). We analyzed various types of QM-cluster models from F-SAPT interaction energies based on how far away the amino acid fragment is from the substrate. We built off a qualitative interatomic contact-based model by extending the model from five to twenty-five additional fragments. We will investigate using both a representative frame from molecular dynamics simulation and the X-ray crystal structure. Additionally, we are studying how the energy decomposition of F-SAPT into electrostatic, induction, and dispersion terms is correlated with the residue fragment distance from the TSA. Preliminary results show that side chains of charged residues outside of the contact-based RIN have total interaction energies greater than 20 kcal/mol, even when > 7 Angstroms away from the TSA. Our focus needs to be on how the uncharged side chain fragments impact the model.