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Triticale As A Source Of Resistance To Wheat Streak Mosaic Virus And Triticum Mosaic Virus, Marcos Winicius Goncalves De Souza

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Wheat streak mosaic virus (WSMV) and Triticum mosaic virus (TriMV) present a great threat to wheat production in the Great Plains area of the United States due to the loss of photosynthetic area causing reductions in crop yields. Effective control of these viruses is limited to a few available strategies including controlling volunteer wheat and using currently identified resistant genes to both the vector and viruses. While effective, these genes show temperature sensitivity and yield drag, and evidence that the vectors and viruses can overcome them has been found. Thus, new methods of genetic resistance are urgently needed. Field observations …

Nonlocal Frameworks For Nonlinear Conservation Laws And Advection-Diffusion Processes, Anh Thuong Vo

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Conservation laws are fundamental principles that play an important role in modeling various phenomena in physics, chemistry, and biology. However, their limitations, such as the development of shocks despite smooth initial conditions, are well known. The nonlocal model framework can be used to overcome these challenges. Nonlocal frameworks utilize integral operators that mimic differential operators but also incorporate long-range interactions within a finite horizon. This approach not only allows for non-smooth solutions, but also provides flexibility in modeling different phenomena. This study investigates the convergence of nonlocal divergence operators, defined with a general flux density function, to their classical counterparts. …

Electrical And Morphological Investigation Of A Fe(Ii) Based Spin Crossover Complex And Its Composite, Rifat Mahbub

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Spin crossover (SCO) complexes have unique properties of switching their spin state upon perturbations like temperature, pressure, light, etc. Along with the spin state, different properties vary like structural, electrical, magnetic, optical properties. This enables these materials to be potentially used in various applications like molecular electronics, memory devices, switching devices, sensors and many more. To incorporate spin crossover materials into devices with efficient performance, the electrical behavior needs to be understood. This dissertation aims to investigate the effect of crystal structure on the electrical properties of iron(II) triazole spin crossover complex and how it can be modified for better …

Structural Analysis Of Dj-1 Glyoxalase Activity By Mix-And-Inject Serial Synchrotron Crystallography, Coleman Dolamore

Department of Biochemistry: Dissertations, Theses, and Student Research

Observing enzyme structures while they are catalyzing a reaction has been a major goal of both enzymology and structural biology for decades. With the advent of time-resolved serial X-ray crystallography using X-ray free electron lasers (XFELs) and synchrotron sources, enzyme reactions can be monitored in real time in crystallo. Here, we use two different approaches to study related enzymes involved in methylglyoxal detoxification. For human DJ-1, we used pink beam mix-and-inject serial crystallography (MISC) at the Advanced Photon Source (BioCARS 14-ID) to probe the controversial mechanism of DJ-1’s action on methylglyoxal by using serial Laue diffraction. The high flux …

Data-Driven Drug Repurposing For Immune System-Related Diseases, Sabyasachi Mohanty

Department of Biochemistry: Dissertations, Theses, and Student Research

In this research, we explore a data-driven approach for drug repurposing to enhance the immunomodulatory effect by integrating pattern-based search and genome-scale metabolic modeling. This research helps to find a solution to the preexisting problems of drug discovery which includes expenses and a high amount of time consumption. By leveraging the pre-existing data of the approved drugs to identify the major metabolic pathway changes, we can find new drugs with similar effects with less off-target effects.

The focus on the immune system modulating drugs is due to the high prevalence of immune system-involved diseases and the growing demand for effective …

Utilization Of Probiotics To Compete With Clostridioides Difficile For Nutrient-Niches In A Variety Of In Vitro Contexts, April Elizabeth Johnson

Department of Food Science and Technology: Dissertations, Theses, and Student Research

Clostridium difficile is a major threat to public health and primarily affects at risk groups such as elderly, immunocompromised individuals, and individuals on antibiotics. Many decades of research have been conducted to figure out ways to exclude or reduce C. difficile colonization and toxin production. Two major proposed mechanisms for colonization resistance are production of secondary bile salts and competition for nutrients.

In Chapter 2, we found that antibiotic treatment disrupted bile salt metabolism increasing the levels of the primary bile salt cholate and decreasing the levels of deoxycholate, a secondary bile salt. However, bile salts were not required …

The Influence Of Student-Teacher Relationship Quality On Educational Outcomes For Students With Attention-Deficit/Hyperactivity Disorder, Cassidy Ann Spradlin

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

The purpose of this dissertation study was to examine the associations between student-teacher closeness, student-teacher conflict, and educational outcomes (i.e., academic, social, and behavioral outcomes) for students with elevated symptoms of attention-deficit/hyperactivity disorder (ADHD). Positive student-teacher relationship quality is linked to educational success and has been found to be inversely related to adverse outcomes in the general population. Previous research has examined differences in student-teacher relationship quality for students with ADHD, but the association between student-teacher relationship quality and educational outcomes is not well understood for students with ADHD. This dissertation study examined the association between student-teacher relationship quality and …

Identifying The Relative Abundance Of Cell-Cell Signaling Peptides During Mammalian Hibernation And Anesthetic Administration By Label-Free Peptidomics Analysis, Somayeh Mousavi

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Cell-cell signaling molecules known as neuropeptide and peptide hormones, distributed in both the central nervous system (CNS) and the peripheral nervous system (PNS), regulate a variety of physiological processes including body temperature, feeding, circadian rhythm, reproduction, energy homeostasis, and more. While a number of active neuropeptides structures with physiological functions have been discovered, advances in peptidomic mass spectrometry are enabling researchers to uncover novel, previously unknown, active neuropeptide structures with potential for bioactivities. Using liquid chromatography coupled with tandem mass spectrometry (MS/MS), it is possible to identify a wide range of neuropeptides in single experiments without preselecting specific peptides. Mass …

Assessment Of Foam Decontamination In Tomato Washing Process, Basim M. Alohali

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

The work of the dissertation investigated the efficacy of foam-based decontamination treatments to enhance microbial safety in Roma tomatoes, specifically targeting natural microflora and Salmonella contamination. Growing concerns over foodborne illnesses linked to fresh tomatoes and the limitations of conventional decontamination techniques, such as organic matter built-up and limited microbial reduction, are addressed. The primary objectives were to characterize the physiochemical properties of foams formed using various concentrations of Tween 20 (T20) and sodium dodecyl sulfate (SDS) with and without the addition of sodium hypochlorite (NaOCl) and peracetic acid (PAA), compare the efficacy of foam and traditional dump tank (DT) …

Manipulations Of The Caenorhabditis Elegans Microbiome Reveal Influences Of Detrimental Members On Host Life History Traits, Ashley Elizabeth Foltz

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Microbiomes are a fundamental part of eukaryotic organisms and play a role in both host health and fitness. Although microbiomes are often associated with health and positive effects on the host, certain microbiome compositions are also associated with disease. We used Caenorhabditis elegans and its experimental microbiome, CeMbio to explore the interactions that individual microbiome members have with other microbes, with the host, and how the entire microbiome community interacts with the host. We found that individual CeMbio members have varying effects on host health and fitness compared to the whole community. This suggested that there is synergy occurring in …

Development Of A Durable And Low-Dose Universal Vaccine Against Swine Influenza A Virus, Erika Petro-Turnquist

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Swine Influenza A Virus (IAV-S) imposes a significant burden on the pork industry and poses a great threat to public health due to its zoonotic potential. Susceptibility to human, avian, and swine influenza make pigs the ultimate mixing vessels for reassorted influenza A virus strains. Current vaccination strategies induce short-lived and strain-specific responses against IAV-S. Further, the substantial genetic diversity of IAV-S necessitates consistent revaccination and updating of commercial vaccines. Computational platforms have recently emerged as a promising strategy to develop new-age vaccines against infectious diseases in livestock animals. Here, we describe a computationally derived set of vaccine immunogens, called …

Spatial Ecology Of Mountain Lions Throughout Their Distribution In California, Kyle Duncan Dougherty

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Mountain lions (Puma concolor) have been studied extensively throughout their wide geographic distribution in the Western Hemisphere, but most research has been conducted at relatively small spatial scales. We used GPS telemetry data contributed by researchers in 16 study areas throughout California to advance understanding of mountain lion spatial ecology. First, we investigated multi-scale resource selection of mountain lions relative to spatially varying risk of intentional human-caused mortality associated with livestock depredation management. We show that individuals that proactively avoided mortality risk when selecting home ranges were able to relax their avoidance of risk when making resource selection …

Genetically Modified Bovine Milk-Derived Small Extracellular Vesicles In Drug Delivery, Alice Kah Hui Ngu

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Small extracellular vesicles (SEVs, “exosomes”) are natural nanoparticles that can be endogenously synthesized and also obtained from dietary sources, such as bovine milk SEVs (mEVs). mEVs have been extensively studied and discovered with contributive features that potentially play a role in drug delivery and other therapeutic purposes, such as diagnostic tools. Current studies have shown that mEVs have been used preclinically to carry in targeting drugs, nucleotides, biomolecules, and labels to target metabolic diseases and cancers. Extensive studies have focused on further modifying SEVs to enhance their versatility in pharmaceutical use. In this dissertation, we exhibited one of the ways …

Advancements In Microscale Tensile Testing: A Novel Device For The High Throughput Analysis Of Two-Photon Polymerized Microfibers In Liquid, Grayson D. Minnick

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Two-photon polymerization (TPP) enables the 3D fabrication of micro- and nanostructures from biocompatible materials with high resolutions, reaching into the realm of hundreds of nanometers. Such capabilities are crucial for advancing applications in fields like mechanobiology. As microscale technologies evolve, the precise characterization of material properties becomes increasingly essential. This is especially true for TPP-printed microstructures serving as scaffolds for 3D cell culture and intended for studying the mechanics of tissues. Despite the importance, traditional micro-scale tensile testing methods typically lack scalability and fail to replicate relevant environmental conditions. This dissertation introduces a new device that is specifically designed to …

Population Demography, Occupancy, And Connectivity Of Invasive Bigheaded Carp In The Platte River, Nebraska And Its Tributaries, Blake W. Logan

School of Natural Resources: Dissertations, Theses, and Student Research

Silver Carp Hypophthalmichthys molitrix and Bighead Carp H. nobilis, collectively referred to as bigheaded carp, are invasive species in the United States of America that have expanded their range throughout the Missouri River basin in the last three decades. It may be desirable to develop management plans directed at the monitoring, control, or removal of bigheaded carp within the Missouri River basin. However, a knowledge gap exists regarding bigheaded carp ecology in Missouri River tributaries, which may be important for the development of management plans. As such, this study characterized bigheaded carp population demographics, occupancy, and connectivity in …

Virtual Fencing In Livestock Management: Effects On Beef Cattle Stress And Enhancing Wildlife Conservation, Kaitlyn E. Dozler

School of Natural Resources: Dissertations, Theses, and Student Research

I examined the effects of virtual fencing on beef cattle stress and how implementing the technology can aid wildlife habitat conservation at the University of Nebraska Gudmundsen Sandhills laboratory (GSL) near Whitman, NE. First, I examined how virtual fencing influences acute heart rate changes in beef cattle fitted with the virtual fencing collars. No significant difference in the average heart rate of a cow (P > 0.05) was observed between the 30 min control and virtual fenced periods for both trial dates. Second, I examined the influence of topography on wildlife species richness and presence at GSL using wildlife camera …

Spatial Ecology Of Mountain Lions Throughout Their Distribution In California, Kyle D. Dougherty

School of Natural Resources: Dissertations, Theses, and Student Research

Mountain lions (Puma concolor) have been studied extensively throughout their wide geographic distribution in the Western Hemisphere, but most research has been conducted at relatively small spatial scales. We used GPS telemetry data contributed by researchers in 16 study areas throughout California to advance understanding of mountain lion spatial ecology. First, we investigated multi-scale resource selection of mountain lions relative to spatially varying risk of intentional human-caused mortality associated with livestock depredation management. We show that individuals that proactively avoided mortality risk when selecting home ranges were able to relax their avoidance of risk when making resource selection …

Hybridization Between The Rare Gray-Headed Chickadee And The Abundant Boreal Chickadee In The Midst Of Shifting Climate, Matthew R. Armstrong

School of Natural Resources: Dissertations, Theses, and Student Research

As species respond to changing climate, distributions and abundances may shift and alter species interactions. Hybridization, a relatively widespread phenomenon becoming more common with climate change, can have beneficial and detrimental effects on population growth rates and genetic integrity. Beneficial effects due to the introduction of advantageous alleles and increased genetic diversity may result from hybridization. Species may also accrue fitness costs associated with changing climates if mismatches occur between environmental variables and phenotypes. The gray-headed chickadee, Poecile cinctus lathami, is an extremely rare songbird that has experienced marked declines in recent decades within its restricted distribution in Alaska …

Phylogeny And Disparity Of Ammonoid Family Acanthoceratidae Over Ocean Anoxic Event 2, Lindsey Howard

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

The widespread use of genera as proxies for species in paleobiological studies might affect the results of these studies. Although most attention has been given to taxonomic diversity studies, this could also be true of disparity and phylogenetic studies. In particular, the assumption that particular character states truly diagnose all members of a genus might distort results. This study examines the disparity of Acanthoceratid ammonoids at both the generic and species level. 149 species from 42 genera were examined with 52 characters measured. Following the measurements, an inverse modeling simulation was run 100 times to generate a simulated phylogeny with …

French Interwar Popular Romance And Ideals Of Femininity: A Literary And Historical Study Of Magali, Kelly Kamrath

Department of Modern Languages and Literatures: Dissertations, Theses, and Student Research

Against a background of political turmoil, economic crises, and cultural upsets from both within and abroad, France between the two World Wars was home to a flourishing romance novel industry. At first glance lighthearted love stories seem simple and frivolous in comparison to the canonical writings of the time, such as those of Simone de Beauvoir and Jean-Paul Sartre. However, this literature was far from art for art’s sake. The romance novels of interwar France, written half a century before the scholarship of romance fiction would truly begin, have yet to receive the attention they deserve. During the interwar period, …

Enhancing Water Sustainability In North Africa: Literature Review And Synthesis Of Current Knowledge Gaps In Sudan, Osman M. A. Adam, Aaron R. Mittelstet, Derek M. Heeren, Troy E. Gilmore

Department of Agricultural and Biological Systems Engineering: Presentations and White Papers

This study delves into the critical role of groundwater in addressing global water challenges, with a focus on the Nubian Sandstone Aquifer System (NSAS) in North Africa. Groundwater constitutes a source of potable water, irrigation, and industrial use, especially in arid regions where surface water is limited. We analyzed the status of water quantity, withdrawals, recharge, and geological characteristics in the NSAS, specifically in Sudan, Egypt, Libya, and Chad. Though the NSAS is largely an untapped resource, we evaluated various scenarios to determine the quantity of cropland that can be sustainably irrigated. The NSAS is located in an arid region, …

Assessing Soil Properties For Optimized Irrigation Development In Sudan, Northern Africa, Suhib Hamid, Derek M. Heeren, Aaron R. Mittelstet, Saleh Taghvaeian, Randall S. Ritzema

Department of Agricultural and Biological Systems Engineering: Presentations and White Papers

Sustainable irrigation methods maximize agricultural productivity in Northern African countries like Sudan. This project evaluates soil properties to develop optimized irrigation strategies for Sudan's arid and semi-arid climate. Assessing soil characteristics such as texture, infiltration rates, and nutrient content informs the selection of modern irrigation systems. Data from 3,192 locations, collected using GPS and ring infiltrometers for infiltration rates, alongside laboratory analyses for soil properties, were employed. A ranking system determined suitable irrigation systems for specific soil classes, considering factors like slope, wind, crop tolerance, available water capacity (AWC), drainage, germination, capital cost, labor cost, maintenance, and evapotranspiration (ET). The …

Investigating The Abilities Of Potentially Beneficial Bacteria For Increasing Nitrogen-Use Efficiency In Maize, Lexie R. Foster

School of Biological Sciences: Dissertations, Theses, and Student Research

Global agriculture relies heavily on the use of synthetic nitrogen fertilizer to meet the current global food demand. Unfortunately, the average nitrogen-use efficiency (NUE) of maize (Zea mays) is approximately 50 percent. Improving the NUE of maize is essential for meeting the growing global food demand while also decreasing the negative environmental impacts caused by losses of nitrogen fertilizer due to runoff and volatilization. Harnessing the symbiotic relationship between plants and the soil microbiome may be one method for increasing the NUE in crops such as maize. In the present study, a set of potentially beneficial bacterial species …

Dynamic Metabolic Flux Analysis Amidst Data Variability: Sphingolipid Biosynthesis Case Study In Arabidopsis Thaliana Cell Cultures, Abraham Boluwatife Osinuga

Department of Chemical and Biomolecular Engineering: Dissertations, Theses, and Student Research

Sphingolipids are pivotal for plant development and stress responses. Growing interest has been directed towards fully comprehending the regulatory mechanisms of the sphingolipid pathway. In this study, we explore its de novo biosynthesis and homeostasis in Arabidopsis thaliana cell cultures, shedding light on fundamental metabolic mechanisms. Employing ¹⁵N isotope labeling and quantitative dynamic modeling approach, we obtained data with notable variations and developed a regularized and constraint-based Dynamic Metabolic Flux Analysis (r-DMFA) framework to predict metabolic shifts due to enzymatic changes. Our analysis revealed key enzymes such as sphingoid-base hydroxylase (SBH) and long-chain-base kinase …

Archaeoentomology: Arthropods And Humans, Current Works In Archaeoentomology, Paz Vigil

Department of Entomology: Distance Master of Science Projects

This paper presents a brief literature review, exploring human and insect interaction, and how such research aids the ongoing construction of the archaeological and entomological record. This field, a combined subset of both entomology and archaeology, is both complex and rich as well as young and still growing. This literature review is not meant to be an exhaustive or comprehensive exploration of this subject, but it will serve as part of a foundation for those interested in the topic or wanting to conduct further exploratory study in this field. The intent is to highlight the practical applications of Archaeoentomology, using …

Heat Stress Changes The Bovine Methylome And Transcriptome And Investigation Of Two Novel Genetic Defects In Cattle, Rachel Renae Reith

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Heat stress is a major concern for livestock producers due to its negative impact on animal health and productivity. Heat stress does so by altering expression of genes through different regulatory mechanisms such as DNA methylation. Understanding how heat stress alters gene expression will help elucidate the genetic basis of physiological changes as well as identify targets for possible heat stress mitigation. The purpose of the first study was to understand how heat stress alters the adipose and skeletal muscle transcriptomes in zilpaterol-fed Brahman, as zilpaterol improves muscle growth and may mitigate the effects of heat stress. Differential expression and …

A Study Of Electron- And Photon-Induced Dissociative Electron Attachment To Molecules And Within Anion-Molecule Clusters, Mahmudul Hasan

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Dissociative electron attachment (DEA) is a resonant process in which a molecule captures a low-energy electron, forming a transient negative ion (TNI). Subsequently, this unstable TNI fragments into a stable anion and one or more neutral fragments. DEA is crucial in various phenomena, ranging from atmospheric and radiation chemistry to processes occurring in plasmas, and is particularly significant in the context of radiation-induced damage to biological molecules. This study uses different experimental methods to better understand the fragmentation in molecular anions forming through dissociative photoexcitation and electron attachment. We have developed an experimental apparatus for dissociative photoexcitation studies. This apparatus …

Electronic Properties Of Group-Iii Nitride Semiconductors And Device Structures Probed By Thz Optical Hall, Nerijus Armakavicius, Philipp Kühne, Alexis Papamichail, Hengfang Zhang, Sean Knight, Axel Persson, Vallery Stanishev, Jr-Tai Chen, Plamen Paskov, Mathias Schubert, Vanya Darakchieva

Department of Electrical and Computer Engineering: Faculty Publications

Group-III nitrides have transformed solid-state lighting and are strategically positioned to revolutionize high-power and high-frequency electronics. To drive this development forward, a deep understanding of fundamental material properties, such as charge carrier behavior, is essential and can also unveil new and unforeseen applications. This underscores the necessity for novel characterization tools to study group-III nitride materials and devices. The optical Hall effect (OHE) emerges as a contactless method for exploring the transport and electronic properties of semiconductor materials, simultaneously offering insights into their dielectric function. This nondestructive technique employs spectroscopic ellipsometry at long wavelengths in the presence of a magnetic …

Evaluation Of An Autonomous Acoustic Surveying Technique For Grassland Bird Communities In Nebraska, Grace E. Schuster, Leroy J. Walston, Andrew R. Little

School of Natural Resources: Faculty Publications

Monitoring trends in wildlife communities is integral to making informed land management decisions and applying conservation strategies. Birds inhabit most niches in every environment and because of this they are widely accepted as an indicator species for environmental health. Traditionally, point counts are the common method to survey bird populations, however, passive acoustic monitoring approaches using autonomous recording units have been shown to be cost-effective alternatives to point count surveys. Advancements in automatic acoustic classification technologies, such as BirdNET, can aid in these efforts by quickly processing large volumes of acoustic recordings to identify bird species. While the utility of …

Daily Eicosapentaenoic Acid Infusion In Iugr Fetal Lambs Reduced Systemic Inflammation, Increased Muscle Adrβ2 Content, And Improved Myoblast Function And Muscle Growth, Haley Beer, Taylor A. Lacey, Rachel L. Gibbs, Micah S. Most, Zena M. Hicks, Pablo C. Grijalva, Eileen S. Marks-Nelson, Ty B. Schmidt, Jessica Lynn Petersen, Dustin T. Yates

Department of Animal Science: Faculty Publications

Intrauterine growth-restricted (IUGR) fetuses exhibit systemic inflammation that contributes to programmed deficits in myoblast function and muscle growth. Thus, we sought to determine if targeting fetal inflammation improves muscle growth outcomes. Heat stress-induced IUGR fetal lambs were infused with eicosapentaenoic acid (IUGR+EPA; n = 9) or saline (IUGR; n = 8) for 5 days during late gestation and compared to saline-infused controls (n = 11). Circulating eicosapentaenoic acid was 42% less (p < 0.05) for IUGR fetuses but was recovered in IUGR+EPA fetuses. The infusion did not improve placental function or fetal O2 but resolved the 67% greater (p < 0.05) circulating TNFα observed in IUGR fetuses. This improved myoblast function and muscle growth, as the 23% reduction (p < 0.05) in the ex vivo differentiation of IUGR myoblasts was resolved in IUGR+EPA myoblasts. Semitendinosus, longissimus dorsi, and flexor digitorum superficialis muscles were 24–39% lighter (p < 0.05) for IUGR but not for IUGR+EPA fetuses. Elevated (p < 0.05) IL6R and reduced (p < 0.05) β2 adrenoceptor content in IUGR muscle indicated enhanced inflammatory sensitivity and diminished β2 adrenergic sensitivity. Although IL6R remained elevated, β2 adrenoceptor deficits were resolved in IUGR+EPA muscle, demonstrating a unique underlying mechanism for muscle dysregulation. These findings show that fetal inflammation contributes to IUGR muscle growth deficits and thus may be an effective target for intervention.