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Teeth That Tell Time: Elemental Analysis From Shark Teeth, Gisele-Elizabeth Perez, David Turner

Research Papers

Sharks (Chondrichthyes) have hunted in the oceans for over 400 million years, their teeth leaving history behind, constantly becoming a part of the fossilization process (Worm et al. 2013). Their survival throughout 5 major extinctions is due to their ability to adapt easily with slow metabolism, a wide range of diet, and an efficient physiology. Shark teeth are vital to the hunting and consumption of their prey, making it a point for scientists to study them. Their tooth minerals contain fluorapatite in their enameloid, and dentin in the “root” of the tooth, with extinct species containing dentin and hydroxyapatite in …

Teeth That Tell Time: Elemental Analysis From Shark Teeth, Gisele-Elizabeth Perez

Posters - 2026

Sharks (Chondrichthyes) have hunted in the oceans for over 400 million years, their teeth leaving history behind, constantly becoming a part of the fossilization process (Worm et al. 2013). Their survival throughout 5 major extinctions is due to their ability to adapt easily with slow metabolism, a wide range of diet, and an efficient physiology. Shark teeth are vital to the hunting and consumption of their prey, making it a point for scientists to study them. Their tooth minerals contain fluorapatite in their enameloid, and dentin in the “root” of the tooth, with extinct species containing dentin and hydroxyapatite in …

Sustainable Mitigation Of Microplastic Pollutants Using Native Plant Species, Antonio Martinez

Posters - 2026

Microplastics (MPs) are defined as small plastic particles that come from the degradation of plastics [Ziani et al. 2023], that hold a regular or irregular shape, ranging from 1μm to 5 mm [Campanale et al. 2025]. This diminutive size makes them virtually impossible to remove once released into the environment[Lee et al. 2023]. Furthermore, biological, chemical, and physical processes break MP's further down in the environment, causing them to exist in nano-level sizes (1nm-1μm) [Lee et al. 2023], further exacerbating their threat to critical habitats. However, recent studies have shown MP contamination expands beyond the natural environment as recent studies …

Mapping Sensory Landscapes: Distribution And Arrangement Of The Anterior Lateral Line System In Texas Catfish, Tatiana Flores, Ruben Tovar

Research Papers

Fish have a system of sensory organs known as the lateral line system. This system contains numerous mechanoreceptive neuromasts and electroreceptive ampullary organs (Northcutt et al, 2000). Neuromasts are small, hair-like structures located within canals in the lateral line system just under the fish’s skin and are open to the environment through small pores visible on its skin (Parker, 2025). Water flows into these canals through the pores which stimulates the sensitive hair cells, resulting in electrical signals sent to the fish’s brain. The brain interprets these signals and creates “images” of the fish’s surroundings, helping it to see even …

Leveraging Aspiring And Inspiring Mentorship Relationships To Promote Stem Persistence, Rayann K. Hoppe

Honors Thesis

While several mentorship interventions for STEM students already exist, persistence and retention in STEM fields remain relatively low. Additionally, there is limited research examining the intersections between aspiring (upward) and inspiring (downward) mentorship roles.

This article aims to address these gaps by examining existing literature and mentorship frameworks, with a focus on how mentorship dynamics influence STEM persistence. Two principal findings emerge from the literature: (1) effective mentorship should be conceptualized as an interconnected ecosystem rather than a hierarchical structure, and (2) the intersection of aspiring and inspiring roles contributes to the development of identity, self-efficacy, and a sense of …

Ecological Studies Of Wolves On Isle Royale, Sarah R. Hoy, Rolf O. Peterson, John A. Vucetich

Ecological Studies of Wolves on Isle Royale

Annual Report 2025-2026

Gamma Sigma Delta, Nebraska Chapter Newsletter, Issue #69 Spring 2026

Gamma Sigma Delta, Nebraska Chapter: Newsletters

President's message, Dustin Loy

Undergraduate Scholarship Awards

2026 Chapter Officers and Committees

Faculty Awards

Membership info and dues form

Grad Student Scholarship

Award of Merit

NU Foundation Fund

New Initiates

Save the Date

In Memoriam:
Kara Daye Heideman (March 31, 1980-December 11, 2025)
L. Dale Van Vleck (June 11, 1933-December 23, 2025)
James (Jim) Eugene Specht (September 12, 1945-February 13, 2026)
Irvin Thomas Omtvedt (June 12, 1935-April 6, 2026)
Fayrene L. Hamouz (June 6, 1946-April 8, 2026)
Robert L. Raun (April 22, 1928-April 22, 2026)

Optimizing Barley Stripped Mosaic Virus Coat Protein Stability For Palladium Nanorod Biotemplating Via Terminal His-Tag Positioning, Emilie Hayes

Honors Theses

Viral biotemplating has become an exciting approach towards the production of nanomaterials with a controlled size and morphology. Rod-shaped plant viruses provide structurally consistent scaffolds that can guide the assembly of inorganic nanostructures, which can offer a biologically inspired platform to nanoscale material design. In the current study, computational modeling was used to examine the effect of palladium precursor chemistry on the reaction with viral protein templates. Molecular dynamics simulations were performed to test the stability of the viral scaffold, and the influence of N-terminal and C-terminal His-tag on protein flexibility. These simulations revealed that the viral coat protein is …

Evaluating The Environmental Parameters Impacting Spawning Movement Of Gulf Sturgeon (Acipenser Desotoi) In The Bouie River System., Olivia St. Germain

Honors Theses

The anadromous Gulf Sturgeon (Acipenser desotoi) is federally listed as “threatened” and is natal to seven rivers from Louisiana to Florida. Only one spawning reach for Gulf Sturgeon natal to the Pascagoula River has been verified via the collection of eggs and larvae; a reach of the lower Bouie River. This reach is anthropogenically modified by four gravel mining formations, hereafter referred to as pits. The greater depths associated with this area have prompted previous researchers to suggest that Gulf Sturgeon may over-summer in pit formations instead of migrating to downstream holding areas in the Pascagoula River after spawning. The …

Mitochondria Dynamics In Microglia During Health, Inflammation, And Aging, Alicia Nicole Pietramale

Dartmouth College Ph.D Dissertations

Microglia continually surveil the brain, allowing for rapid detection of tissue damage or infection. Microglial metabolism is linked to tissue homeostasis, yet how mitochondria are subcellularly partitioned in microglia and dynamically reorganize during surveillance, injury responses, and phagocytic engulfment in the intact brain has remained unclear. In this dissertation, I combine intravital imaging, ultrastructural analyses, and metabolic and cytoskeletal markers to investigate how mitochondrial organization relates to microglial function across health, inflammation, and aging.

I first show that microglial processes diverge in their mitochondrial content, with some containing multiple mitochondria while others are completely void. This heterogeneous partitioning is conserved …

Evaluation Of Tick-Derived Peptides For Transmission-Blocking Vaccine Candidates, Madelyn Futral

Honors Theses

The lack of effective preventive measures for tick-borne diseases represents a major public health challenge. Transmission-blocking vaccines targeting tick molecules essential for feeding or reproduction could provide a sustainable and broad-spectrum solution. In this study, we evaluated two tick-derived proteins as potential vaccine antigens, subolesin, a key regulator of blood-feeding and cellular processes, and vitellogenin, a protein involved in egg development. Using bioinformatic tools, we identified immunogenic peptide sequences from each protein and chemically conjugated them to virus-like particles (VLPs) to enhance antigen presentation. C57BL/6 mice were immunized intradermally with VLP-peptide conjugates, followed by a booster dose. Blood and spleen …

Glioblastoma Multiforme: A Pathologic Breakdown Of One Of Neuro-Oncology's Greatest Challenges, Rosemary Westphal, Ms

Student Papers, Posters & Projects

Glioblastoma multiforme is the most common adult primary tumor with a grim median survival time of 14.6 months. It is characterized by rapid progression, diffuse infiltration, and rather poor clinical outcomes. The WHO classifies GBM as a grade 4 diffuse astrocytic tumor with distinctive histopathological features including high mitotic activity, marked cellular atypia, microvascular proliferation, and necrosis. Advances in molecular diagnostics have further classified GMB into IDH-wild type and IDH-mutant subtypes, with important therapeutic and prognostic implications. Key genetic alterations, such as EGFR amplification, PTEN loss, TP53 mutations, TERT promoter mutations, and MGMT methylations, have been identified as contributing to …

Effects Of Kiwifruit Extract On Apoptosis And Cytokine Production In Inflamed Thp-1-Derived Macrophages, Adrian Cruz, Isbella Brigman

Posters - 2026

White blood cells are essential components of the immune system involved in helping defend the body against infections. Macrophages are a type of white blood cell that play a major role in stimulating and regulating the inflammatory response. Inflammation is a natural response of the immune system to infection, injury, or harmful stimuli. Scientific research commonly studies inflammation by exposing immune cells to lipopolysaccharide (LPS). Macrophages stimulated with LPS undergo changes in cell processes such as apoptosis which is programmed cell death. Apoptosis is crucial for the immune system that helps eliminate infected or damaged cells to prevent the spread …

The Effects Of Mycoplasma Pneumoniae Cards Toxin On M2 Macrophage Polarization And Formation, Ria Modi

Posters - 2026

Macrophages are key cells of the innate immune system, playing essential roles in host defense, tissue homeostasis, and inflammation. Depending on stimuli, macrophages can polarize into distinct functional phenotypes, characterized as classically activated (M1) or alternatively activated (M2) macrophages. M2 macrophages are associated specifically with anti-inflammatory responses, tissue repair, and immune regulation. They contribute to wound healing and can regulate host responses during infection. Community-acquired respiratory distress syndrome (CARDS) toxin, a key virulence factor of Mycoplasma pneumoniae, plays a role in altering host immune responses, but its impact on M2 macrophage function and polarization remains unclear.

Comparing Head Shape Of Polymorphic Subterranean E. Latitans And Subterranean E. Sp. 4, Brandon Chapa, Jordan Cosgrove, Lizzeth Holguin

Posters - 2026

Eurycea latitans (E. latitans) from Honey Creek Cave and unnamed Eurycea species from New Braunfels, Texas (E. sp. 4) are two paedomorphic subterranean species. E. latitans is polymorphic, meaning it also exists as a surface species. Similarities in morphology of subterranean salamander species may be due to convergent evolution as a result of living in similar environments. These similarities include having flatter, wider heads, and wider mouths than surface species (Tovar et al. 2025). Variation may also exist among different subterranean salamander species. Texas Eurycea salamanders display “complex patterns of morphological divergence”, suggesting that isolation and local environmental pressures can …

Impact Of Liver-Secreted Small Extracellular Vesicles On Myotube Funcation, Tatiana Barrantes, Ioannis Tsialtas, Qing Zhang, Kevin Koronowski

Posters - 2026

Extracellular vesicles (EVs) mediate intercellular communication by transferring molecular signals between tissues. Liver-derived EVs contribute to metabolic regulation and have been implicated in tissue cross-talk during health and disease. Skeletal muscle is a highly metabolic tissue that depends on mitochondrial respiration for energy production. However, whether liver-secreted EVs influence myotube mitochondrial function remains unclear. Here, we investigate the impact of liver-derived EVs on myotube mitochondrial respiration.

The Missing Lynx: Ivestigating Passive And Active Rewilding With The Eurasian Lynx, Isaiah Charles, Tatiana Flores, Isabella Lopez

Posters - 2026

The Eurasian Lynx (Lynx lynx) is a wild cat native to the boreal forests, mountains and grasslands of Europe and Asia (Bhattacharyya, 2025). The Eurasian lynx keep ungulate populations in check which allow for forests to recover from overgrazing, promoting biodiversity and ecological balance. However, the Eurasian lynx had become locally extinct across Europe by the 1900s due to habitat loss, hunting by farmers in retaliation for predation of livestock and the illegal fur trade. Conservation and ecological restoration efforts to rebuild the lynx population have been underway. Rewilding is a form of ecological restoration involving the reintroduction of a …

Comparing Gngt1 Expression In Eye Tissue Of Polymorphic Salamander Species Through Development, Fiona Coulbourne, Camila Cardozo, Macarena Machado, Ruben Tovar

Posters - 2026

The effect of the environment on organisms and their adaptations is widely studied. When exposed to different environmental niches, phenotypic adaptation is observed even within species. Animals that live in dark cave environments show a loss of their eyesight, since this sense is no longer useful to keep. Previous research has studied salamanders of the clade Eurycea and compared gene expression to subterranean and surface phenotypes1. E.pterophila is observed to express these two phenotypes depending on its environment, either Preserve Cave (subterranean) or Comal Springs (surface). Subterranean variant shows reduced eye volume and assumes to have decreased eyesight. Utilizing RNASeq …

Investigating The Endogenous & Synthetic Estrogens To The Three Estrogen Receptor Subtypes Of Teleost Fish, Ann Cyril

Posters - 2026

Estrogen and the estrogen receptors are important biological and physiological processes. The various types of estrogen include estrone, estradiol and estriol. Estradiol’s main function is to maintain the reproductive system. Estrone’s main function is to develop the female's reproductive functions. Estriol’s main function is to aid the female's sexual developments but is on the weaker side. The fish, Atlantic Croaker, has three different estrogen receptors: ERα, ERβa, and ERβb. Based on the estrogen receptors, it appears that their binding affinities do differ in strength. Each estrogen receptor has different amino acids involved that could contribute to the difference in their …

Beluga Buddies: The Preferred Social Network Of Belugas In Managed Care, Valery Marinelarena, Diamond Garcia

Posters - 2026

Belugas societies are not fixed  and group composition is everchanging. Group composition can also influence behavior. This study aims to examine the preferred social networks and the role age plays in the behavioral diversity within a group of managed care belugas housed at Sea World San Antonio. Results Supported TYO had a preferred, non-random social network and ATL performing more chinslaps than TYO.

The Effects Of Sour & Spicy Food On Visual & Auditory Reflexes, Aditi Kumar, Alondra-Sophia Martinez, Magdalena E. Saad, Emma J. Welsch

Posters - 2026

• The reflex reaction time measures how quickly the nervous system can respond to a stimulus. • In the experiment, both visual and auditory reflexes were measured to evaluate differences in reaction time after the consumption of sour and spicy foods. • Spices and herbs produce different signals that interact with the nervous system. (McMullen 2024) • Comparing the response times from before and after consumption, this experiment allowed us to determine if different tastes affect reflex reaction times.

Investigating Rad14 Gene Nucleotide Excision Repair On G-Quadruplexes, Juan Pablo Olvera Rodriguez, Tyna Trevino, Yvette Gonzalez, Georgia Romike

Posters - 2026

DNA is typically found as a double-stranded helical structure; however, it can be found in different types of structures, such as G-quadruplexes (G4s). These are structures formed when DNA sequences are rich in Guanines, which interact with each other by hydrogen bonding, forming stacked G-tetrads. These guanine-rich structures are known for interacting with DNA during important cell processes, such as recombination and replication, leading to instability and DNA damage (Grey et al., 2014). If not treated properly, these structures may contribute to mutations and cancer development. To solve these issues, cells have developed maintenance pathways such as Nucleotide Excision Repair …

An Investigation In The Physiological Effect Of Microplastic And Chemical Mixtures In The Body Length Of C. Elegans, Gregory Guantos, David M. Mares, Jennifer C. Harr Phd

Posters - 2026

• Microplastics (MP) are pieces of plastic less than 5 micrometers (mm). Microplastics are found in our environment and have even been found in the food humans consume, including in drinks from plastic bottles (Hu 2020).

• Di-butyl Phthalate (DBP) is a chemical known as a plasticizer commonly used in PVC applications, ink, fragrances, and adhesives

• Di-butyl Phthalate has been found to have negative effects on the physiological length of C. elegans (Xiyan 2018)

• Microplastics have similarly been found to decrease the physiological length of C. elegans (Schöpfer 2020)

• The combined effects of MPs and DBP include …

Assessing Differential Expression In Skin Of Surface Versus Subterranean Salamanders (Eurycea) Through Development, Chiara Angelyn Maldonado, Van Nguyen, Amy Torres

Posters - 2026

In salamanders, previous findings have shown that subterranean environments impose different selection pressures on sensory systems than surface environments do (1). Differences in ocular development between phenotypes is part of ongoing research to better understand the evolutionary and molecular underpinnings. Studies have shown that parallel ocular development occurred in subterranean and surface phenotypes, while pax6 expression decreased in latter stages of development of subterranean species (2). These insights of gene labeling and expression as well as reduction of ocular structures in latter stages of development provide a stage for understanding evolutionary processes and genetic mechanisms as well as having potential …

Nucleotide Excision Repair In Yeast, Kinleigh Mines, Larry Ramirez, Jacob Rodriguez, Delynda Gonzalez

Posters - 2026

DNA damage occurs constantly in cells due to environmental factors and normal cellular processes, making DNA repair pathways essential for maintaining genomic stability (Hindi et al., 2021). One major repair mechanism is Nucleotide Excision Repair (NER), which is responsible for recognizing and removing bulky DNA lesions that distort the double helix structure (Scharer, 2013). In Saccharomyces cerevisiae (yeast), the RAD14 gene plays a critical role in this pathway by helping identify and initiate repair of damaged DNA (Scharer, 2013). Another source of instability comes from the formation of G-quadruplex (G4) structures, which are secondary DNA configurations that can interfere with …

Emerald Bowfin Amia Ocellicauda Ecology In Three Minnesota Lakes: Abundance, Age Analysis, Diet Composition, And Stable Isotope Food Web, Griffin Blegen

Biology Graduate Theses

The Emerald Bowfin Amia ocellicauda is a predatory fish species native to Minnesota that has often been discriminated against. This research expands ecological knowledge of Bowfin in Minnesota and provides population data to guide future management. Bowfin were sampled in the spring of 2024 and 2025 and a multi-census mark–recapture model was used to estimate abundance in three lakes. Estimated populations were 196 individuals in Little Toad Lake (95% CI: 116, 242) or 4.4 fish/littoral ha (95% CI: 2.7,5.7), 657 in Lake Sarah (95% CI: 436, 1014) or 4.2 fish/littoral ha (95% CI: 3.0, 6.7), and 612 in Gun Lake …

Multiparametric Mri To Predict Response To Irreversible Electroporation Plus Anti-Pd-1 Immunotherapy In Pancreatic Ductal Adenocarcinoma, Qizhen Cao, Mark D Pagel, Charles V Kingsley, Jingfei Ma, James P Long, Xiaoxia Wen, Seth T Gammon, Jorge Delacerda, Sanaz Javadi, Chun Li

Faculty, Staff and Student Publications

Purpose: To investigate contrast-enhanced T1-weighted MRI and diffusion-weighted magnetic resonance imaging (DWI) for early prediction of tumor response to combined irreversible electroporation (IRE) and anti-PD-1 immunotherapy.

Methods: Murine pancreatic ductal adenocarcinoma (PDAC) cells KRAS* were inoculated into the pancreas of C57BL/6 mice. IRE was performed when tumors became palpable. After IRE, mice received six intraperitoneal injections of anti-PD-1 over 2 weeks. T2-weighted MRI, T1-weighted MRI with macromolecular contrast agent poly(L-glutamic acid)-conjugated gadolinium (PG-Gd), and DWI were performed before and after IRE. Survival was analyzed using Kaplan-Meier curves. Mice surviving at least 100 days without recurrence after IRE were considered complete …

Neutrophil-Microglia Interaction Drives Motor Dysfunction In A Neuromyelitis Optica Model Induced By Subarachnoid Aqp4-Igg, Fangfang Qi, Vanda A Lennon, Shunyi Zhao, Yong Guo, Husheng Ding, Caiyun Liu, Whitney M Bartley, Tingjun Chen, Claudia F Lucchinetti, Long-Jun Wu

Faculty, Staff and Student Publications

Neutrophils and neutrophil extracellular traps (NETs) contribute to early neuromyelitis optica (NMO) histopathology initiated by IgG targeting astrocytic aquaporin-4 (AQP4) water channels. Yet, the mechanisms underlying neutrophil recruitment and their pathogenic roles in disease progression remain unclear. To investigate molecular-cellular events preceding classical complement cascade activation in a mouse NMO model, we continuously infused, via spinal subarachnoid route, a non-complement-activating mouse monoclonal AQP4-IgG. Parenchymal infiltration of netting neutrophils containing C5a ensued with microglial activation and motor impairment but no blood-brain barrier leakage. Motor impairment and neuronal dysfunction both reversed when AQP4-IgG infusion stopped. Two-photon microscopy and electron microscopy-based reconstructions revealed …

Gompertz Growth With A Shared Carrying Capacity Optimally Simulates Primary And Metastatic Tumor Growth Dynamics, Pirmin Schlicke, Preethi Korangath, Xiaoxi Pan, Caner Ercan, Kathleen Gabrielson, Lyndsey Werhane, Yinyin Yuan, Sébastien Benzekry, Robert Ivkov, Heiko Enderling

Faculty, Staff and Student Publications

Background: Cancer is a systemic disease with most deaths attributed to metastatic burden. Primary and metastatic tumors, albeit at different anatomic locations, are interconnected through multiple biological processes. Pre-clinical and clinical observations of growth acceleration of metastases after surgery, or abscopal effects outside the radiation field are widely reported, yet reliably triggering favorable and avoiding unfavorable systemic responses remains an unmet clinical need. Understanding local and systemic tumor interaction dynamics will help guide future treatments.

Methods: We analyze the data of multiple in vivo tumor models. We formalize the systemic interplay of tumors as mathematical differential equation and calibrate parameters …

Structural-Functional Analyses Of The Huntingtin/Hap40 Complex In Drosophila And Humans, Stephen M Farmer, Amanda Solbach, Shiyu Xu, Beatriz Rios, Xin Ye, Amy Gao, Daniela Covarrubias, Yue Yu, Lili Ye, Vicky Chuong, Erin Furr Stimming, Haiqing Zhao, Sheng Zhang

Faculty, Staff and Student Publications

Huntington's disease (HD) is a neurodegenerative disorder caused by an abnormal CAG expansion in the Huntingtin (HTT) gene. Given its simple genetic cause but complex pathogenic mechanisms, interest in targeting HTT for HD treatment is growing, necessitating a clear understanding of HTT regulation. HTT protein primarily exists in a core complex with HAP40, forming a highly ordered structure with two large globular domains connected by a bridge. We previously demonstrated that HAP40 is conserved in