Digital Commons Network^™

Characterizing The Material Properties Of Abdominal Organs, Blake Allen Johnson

Theses and Dissertations

Understanding the behavior of abdominal organs under load will greatly improve several fields involving injury biomechanics. In order to determine the behavior of abdominal organs under load and be able to predict the response, the mechanical properties need to be properly characterized. The characterization of these properties will provide researchers the ability to create finite element models that will provide a better understanding of the mechanism of injury resulting from traumatic events.

Finite element models of today, that simulate traumatic injuries, lack properly characterized material properties. The current body of literature contains a large range of material property values which …

Two Fields, One Pellet: Combining Demographics And Population Genetics Through Non-Invasive Sampling Of Snowshoe Hare Fecal Pellets In Michigan., Genelle Nicole Uhrig

Theses and Dissertations

As climate continues to change at a rapid rate, species are increasingly vulnerable to the resulting environmental changes. This is especially true for species whose fitness is closely linked to climate-associated environmental conditions. One of these vulnerable species is snowshoe hare, Lepus americanus, who depends on the timing and duration of snowfall to provide camouflage when they go through seasonal pelage changes from brown in the summer to white in the winter. Whereas snowshoe hare are stable across the core of their range, populations along the southern range edge are experiencing declines due to climate driven environmental changes that cause …

Heirloom And Hybrid Corn In The American Corn Belt: An Ethnography Of Seed Saving Practices, Rachelle Halaska

Theses and Dissertations

This ethnographic study examines the practices and context of contemporary heirloom corn seed saving practices and projects in the American Corn Belt. It examines heirloom corn conservation and hand pollination practices at Seed Savers Exchange in Decorah, Iowa in 2015. From there the study extends to interviews with heirloom farmers, breeders and gardeners in Wisconsin and Illinois. The findings indicate that the lines between the mainstream and the margins of corn production are highly blurred, and that there is a considerable amount of cross-pollination of ideas and practices between alternative corn farming and dominant industrial hybrid production in the American …

Quantifying The Variability In Heavy Metal Concentrations In Produce Grown In Metals-Rich Soil, Harris Lowell Byers

Theses and Dissertations

Childhood Pb exposure is associated with a multitude of poor health outcomes. In food-insecure areas, growing fresh produce in residential backyard gardens is one option for parents; however, commonly grown crops are known to accumulate Pb in consumable tissues when grown in metals-rich soils. A variety of produce representing a continuum of consumable tissues were grown in soils collected from two residential vegetable gardens, a former metal foundry, and commercial topsoil purchased from a local hardware store. The concentrations of heavy metals in crop tissues were measured with custom wavelength dispersive X-ray Fluorescence (WD-XRF) spectroscopy and portable energy dispersive X-ray …

Cyanobacterial Harmful Algal Bloom Ecology And Cyanotoxins In The Eutrophic Lake Winnebago-Green Bay Water System, Sarah L. Bartlett

Theses and Dissertations

Cyanobacterial harmful algal blooms (cyanoHABs) are frequently observed in water bodies used for recreation and drinking water production and can be detrimental to humans, animals, and general water quality. CyanoHABs are natural occurrences, but human activities such as agriculture, land use change, and runoff from urban and rural landscapes can promote and accelerate their expansion. The blooms are aesthetically unpleasing scums and can be laden with toxins (cyanotoxins) and toxic or otherwise bioactive peptides (TBPs) that can be harmful to humans and animals. Despite the vast research on cyanoHABs, cyanotoxin and TBP diversity and dynamics within a water column are …

Functional Characterization Of Lt-Hsc Metabolic Activity Dependent On Ahr Activity, Everett Tate

Theses and Dissertations

The cells of the immune system are descended from multipotent hematopoietic stem cells (HSCs) that emerge during development. Multipotency means that a single progenitor HSC can differentiate into any cell of the immune system. HSCs are required to do this for the lifetime of the organism through a process called self-renewal, and as such, any perturbation during development or in the bone marrow can have a trickle-down effect, affecting the self-renewal capacity or ability to terminally differentiate. The aryl hydrocarbon receptor (AHR) is a known regulator of HSCs. The AHR is a transcription factor required for the detoxification of numerous …

Seasonal Offshore/Inshore Migration Of Round Gobies, Erik Carlson

Theses and Dissertations

Since the invasion of round gobies (Neogobius melanostomus) in Lake Michigan, they have become integrated into both the nearshore and offshore food webs. Round gobies can be found in shallower water (<20 m) during the summer, but they disappear from these depths in early fall. They have been collected, occasionally, offshore in depths greater than 70 m during fall and early spring. These observations and other anecdotal evidence indicate that round goby migrate offshore during the fall and return in the spring. To study this, a large remotely operated vehicle (ROV) was used to conduct video transects offshore at various depths. The offshore sampling showed that round gobies migrated away from nearshore habitat in early October and were almost exclusively found deeper than 20 m by November. The round gobies remained offshore (>30 m) until mid-May, when they began the return to nearshore habitat. The cues to start the offshore and return migrations were not the focus of this project, but the fall offshore migrations coincided with decreasing temperatures nearshore in the fall, and in spring, the offshore movement of the thermal bar. The offshore migration in fall provide an increase in forage opportunity for deep, cold-water predators such as …

Cholesterol: A Possible Mediator Of Apoe Risk For Alzheimer's Disease, Michelle Marie Dunk

Theses and Dissertations

Despite the well-established link between the ε4 allele of the apolipoprotein E (APOE) gene and AD, the underlying mechanisms that mediate the risk of developing AD remain elusive. Literature on the role of APOE in cholesterol metabolism suggests that blood cholesterol may be a key factor in the development of AD pathology. Current study aims to investigate whether total cholesterol differs by APOE status and whether this relationship is predictive of AD diagnosis and its biomarkers. Baseline total cholesterol, APOE status, AD diagnosis, global cognitive function, brain Aβ, plasma Aβ40 and Aβ42, and cerebrospinal fluid (CSF) Aβ, tau, and phosphorylated …

Reexamining Object-Based Visual Attention: Understanding The Nature Of Direction-Dependent Attention Shifts, Adam Joseph Barnas

Theses and Dissertations

Attentional selection is a process by which relevant sensory stimuli are afforded enhanced priority for processing over and above irrelevant sensory stimuli. Object-based attention is a form of selection that leads to preferential processing of visual information contained in/on an attended object versus an unattended object. Observers typically exhibit enhanced performance to a target at an invalidly cued same object location compared to a different-object location, which results in a same object advantage as measured by the response time (RT) difference between these two target locations. A growing body of research has shown that object-based effects are small, inconsistent, and …

Sexual Dimorphism And The Shape Of The Proximal Tibia In A Radiographic Sample, Emily Eiseman

Theses and Dissertations

SEXUAL DIMORPHISM AND THE SHAPE OF THE PROXIMAL TIBIA IN A RADIOGRAPHIC SAMPLE

This study investigates the use of radiographs to determine sexual dimorphism in the shape of the tibia. The goal of the research was to identify a small set of markers that would allow researchers to efficiently and accurately determine a person’s sex from a radiograph of the proximal tibia.

The sample consisted of radiographs including 75 females and 46 males ranging in age from 21 to 81. Measurements were taken on 27 points around the area of the knee including the tibia, patella, and femur. The measurements …

An Autism-Causing Variant Misregulates Selective Autophagy To Alter Axon Targeting And Behavior, Tyler Buddell

Theses and Dissertations

Neurodevelopmental disorders cause debilitating disruptions to the cellular mechanisms that underlie development of the brain. Unfortunately, the complexities of neurodevelopmental disorders make them difficult to study, and the molecular mechanisms perturbed by these disorders remain elusive. Better understanding of neurodevelopmental mechanisms, and the related genes involved, will likely yield new insight into neurodevelopmental disorders. A gene that has been associated with a number of neurodevelopmental disorders is the calcium voltage-gated channel subunit alpha1 C (CACNA1C) gene. Common and rare variants of the CACNA1C gene have been associated with autism and other neurodevelopmental disorders including schizophrenia, bipolar disorder and ADHD. However, …

The Curious Case Of Nad-Cleaving Nudix Hydrolases, Atreyei Ray

Theses and Dissertations

Nudix proteins are members of a large family of homologous enzymes that hydrolyze nucleoside diphosphates linked to other compounds (x). These enzymes have catalytic activity on a wide range of substrates such as dNTPs (both canonical and their oxidized forms), nucleotide sugars, alcohols, dinucleoside polyphosphates, dinucleotide cofactors, and nucleoside diphosphates linked to RNA. The bacterial genome encodes around 13, while the human genome encodes for 22 such nudix proteins.

The E. coli genome encodes for a mutT mutator gene, the progenitor of the family expressing the MutT pyrophosphohydrolase (NudA) protein (Treffers et al., 1954; Bhatnagar et al., 1988). The enzyme …

Investigating The Contribution Of Instance-Reliant Learning In Visuomotor Adaptation And Its Generalization, Shancheng Bao

Theses and Dissertations

Motor adaptation has been of great interest in the past two decades as it reflects how movement skills are acquired and consolidated by the nervous system. In our recent studies, instance-reliant learning is considered as an essential component of visuomotor adaptation, since it plays a unique role in fast and automatized control of movement output. The goal of this dissertation is to investigate the nature of instance-reliant learning on two aspects: to determine the differential contributions of algorithmic learning and instance-reliant learning to visuomotor adaptation; and to determine the nature of movement instance involved in visuomotor adaptation and its generalization …

A Seascape Genetics Approach To Studying Genetic Differentiation In The Bull Kelp Nereocystis Luetkeana, Lily G. Gierke

Theses and Dissertations

The brown alga Nereocystis luetkeana is a foundation species found from Alaska to California. In the Salish Sea, N. luetkeana is declining, but little is known about its population structure. We explored N. luetkeana 1) allelic dissimilarity and richness using seven microsatellite markers, and 2) tested models of gene flow in the Salish Sea using a hydrodynamic transport model. Our results suggest that the N. luetkeana distribution is comprised of four genetic co-ancestry groups that are geographically coherent, apart from the separation of the Strait of Georgia/Puget Sound by the Strait of Juan de Fuca. Our model supported that environmental …

Targeting The Γ-Aminobutyric Acid A Receptor (Gabaar) To Alleviate Inflammation For Asthma And Neuropathic Pain, Amanda Nicole Nieman

Theses and Dissertations

The γ-Aminobutyric Acid A Receptor (GABAAR) is a ligand-gated, pentameric chloride channel composed of subunits that include α1-6, β1-3, γ1-3, δ, ε, π, θ, ρ1-3.1-2 The most common arrangement includes two α subunits, two β subunits, and a γ subunit.3 This receptor includes two binding sites for the endogenous ligand γ-aminobutyric acid (GABA) between the α and β subunits and a binding site between the α and γ subunit for benzodiazepines, a large family of positive allosteric modulators.4-5

Benzodiazepines are one of the most prescribed classes of pharmaceuticals to treat anxiety, insomnia, and epilepsy as well as for muscle relaxation.6-7 …

Role Of Regulatory T Cells In The Development And Progression Of Lyme Disease In Balb/C Mice, Kaitlyn Nielsen

Theses and Dissertations

Lyme disease, caused by Borrelia burgdorferi, is an increasingly important public health concern, with tens of thousands of new cases being diagnosed each year, even in previously non-endemic areas. It is known that symptoms of Lyme disease are caused by an inflammatory immune response initiated to aid in clearance of the pathogen. Left unchecked, these inflammatory responses can potentially increase tissue damage, leading to increased disease severity. Mechanisms responsible for the control of the inflammatory response to infection with B. burgdorferi are not entirely understood. Evidence exists that regulatory T (Treg) cells, a population of Foxp3-expressing CD4+ T cells known …

Development Of Indicators For Human Fecal Pollution Using Deep-Sequencing Of Microbial Communities, Shuchen Feng

Theses and Dissertations

The gut microbiome is shaped by both host physiology and environmental factors, which results in unique communities that contain certain members specific to a host. Microbial source tracking (MST) methods that rely on host-specific fecal microorganisms have been applied to detect human fecal pollution over the past two decades. The most common approach uses quantitative polymerase chain reaction (qPCR) to amplify certain sequences of these microorganisms, or human fecal markers. To date, most bacterial human fecal markers have focused on the HF183 cluster within the genus Bacteroides. However, cross-reactions with animals or variable Bacteroides abundance in humans have been found. …

Evaluation Of Cognitive Control Using Non-Gaussian Reaction Time Distributions In Fractionated Executive Function Tasks, Dmitriy Kazakov

Theses and Dissertations

The present study seeks to further investigate and refine the three-factor model of executive function (EF; Inhibition, Shifting, and Monitoring/Updating) known as the unity/diversity framework (Miyake et al., 2000). Past work in this area utilized “power” tasks that prioritize accuracy and difficulty, but real-world problem-solving incentivizes quick and efficient solutions. Ten computerized reaction time (RT) tasks: four elementary cognitive tasks (ECTs; Jensen, 1987; Santos, 2016) with progressively increasing task demands and six EF tasks. The ratio scale of RT necessitated the use of non-Gaussian statistics to better describe distribution shape, while diffusion modeling (DM; Ratcliff, 1978) was used to interpret …

Unraveling Plague Ecology Through Vector And Host Genetics, Rachael Marie Giglio

Theses and Dissertations

The transmission of vector-borne diseases involves complex interactions between vectors and their host species. These complex host-parasite interactions can be difficult to study with traditional, field-based methods. My dissertation aims to use a population genomics approach to elucidate transmission pathways of plague among prairie dog colonies. Plague is a flea-borne, zoonotic disease caused by the bacterium Yersinia pestis. It is infamous for causing the Black Death (1347-1353), one of the most devastating pandemics in human history. Since its emergence in North America around 1900, plague has spread to native rodents, thus creating a sylvatic cycle. Prairie dogs (Cynomys spp.) are …

Multi-Tap Extended Kalman Filter For A Periodic Waveform With Uncertain Frequency And Waveform Shape, And Data Dropouts, Justin Saboury

Theses and Dissertations

Gait analysis presents the challenge of detecting a periodic waveform in the presence of time varying frequency, amplitude, DC offset, and waveform shape, with acquisition gaps from partial occlusions. The combination of all of these components presents a formidable challenge. The Extended Kalman Filter for this system model has six states, which makes it weakly identifiable within the standard Extended Kalman Filter network. In this work, a novel robust Extended Kalman Filter-based approach is presented and evaluated for clinical use in gait analysis. The novel aspect of the proposed method is that at each sample, the present and several past …

Lorelei Localization And Ovule Ultrastructure In Arabidopsis Thaliana, Juleen May Dickson

Theses and Dissertations

Communication between the male and female gametophyte is vital to successful fertilization during sexual reproduction in plants. One of the proteins known to be important for communication between the male and female gametophyte is LORELEI (LRE). Several studies have shown that there are defects in pollen tube guidance and synergid degeneration, however this is the first study that shows that cell wall thickness in the female gametophyte may also be affected. Previous confocal studies have documented that LRE is present both in the filiform apparatus and found in puncta throughout the cytoplasm. This study confirmed this, but our studies suggest …

Exploring Primitive Legume Symbiosis Using Chamaecrista Fasciculata As A Model, Zachary E. Zawada

Theses and Dissertations

Legumes form symbiotic associations with diazotrophs collectively termed “rhizobia” leading to the formation of nodules and N2-fixation and contribute significant amounts of fixed N to agricultural and natural environments. The mechanisms of nodulation and N2-fixation are extensively studied using model legumes that belong to the Papilionoideae, in which nodulation is widespread and advanced. In contrast, very little is known about the mechanisms of nodulation and N2-fixation in in basal Caesalpinioideae subfamily in which nodulation is rare. The nodulating caesalpiniod legume Chamaecrista fasciculata is widespread in North America and is suggested as a complementary model to study legume nodulation because of …

Flavobacterium Gliding Motility: From Protein Secretion To Cell Surface Adhesin Movements, Joseph Johnston

Theses and Dissertations

Flavobacterium johnsoniae exhibits rapid gliding motility over surfaces. At least twenty genes are involved in this process. Seven of these, gldK, gldL, gldM, gldN, sprA, sprE, and sprT encode proteins of the type IX protein secretion system (T9SS). The T9SS is required for surface localization of the motility adhesins SprB and RemA, and for secretion of the soluble chitinase ChiA. This thesis demonstrates that the gliding motility proteins GldA, GldB, GldD, GldF, GldH, GldI and GldJ are also essential for secretion. Cells with mutations in the genes encoding any of these seven proteins had normal levels of gldK mRNA but …

Analysis Of Genes Involved In Metal Resistance And Cytochrome C Maturation In Shewanella Oneidensis Mr-1, Rini Banerjee

Theses and Dissertations

Metals play crucial roles in many cellular processes where they form active centers of metabolic enzymes or participate in electron transfer reactions during respiration. At high concentrations, metals can be toxic and result in the formation of reactive oxygen species and protein denaturation. Bacteria have evolved homeostasis systems to maintain intracellular concentrations of various metals and avoid their toxic effects. The aim of this project is to identify and characterize metal homeostasis systems in the metal reducer Shewanella oneidensis MR-1. This bacterium can use metals and radionuclides as electron acceptors during anaerobic respiration and is therefore a good candidate for …

Cannabis-Using Youth Demonstrated Blunted Rostral Anterior Cingulate Cortex Activation, But Normal Functional Connectivity, During An Emotional Go/No-Go Task, Kristin Elizabeth Maple

Theses and Dissertations

Cannabis use has been associated with deficits in self-regulation, including inhibitory control. Cannabis users have previously exhibited both structural and functional deficits in the rostral anterior cingulate cortex (rACC), a region involved in self-regulation of emotional response and inhibitory control. The present study aimed to examine whether abstinent cannabis users demonstrated abnormal functional activation and connectivity of the bilateral rACC during an emotional inhibitory processing task, and whether gender moderated these relationships. The study also aimed to examine whether bilateral rACC activation and connectivity in cannabis users was related to perceived stress. It was hypothesized that cannabis users would exhibit …

Mechanistic Insights Into Translational Silencing Of Hacl Mrna In Yeast S. Cerevisiae, Leena Sathe

Theses and Dissertations

Protein synthesis is a fundamental life process. Protein synthesis regulates cellular metabolism, cellular growth, the cell cycle, and cell morphogenesis. Technical advances in molecular biology, advanced high-throughput sequencing technologies and recent developments in crystallographic methodologies have aided in better understanding of the process of protein synthesis. Current knowledge of protein synthesis provides us with an overview of the initiation, elongation, and termination steps, general regulatory mechanisms, and molecular functions of the ribosomal rRNA and proteins. However, even with all this information we are far from understanding the detailed sequence of molecular interactions involved in the process of protein synthesis. We …

Dissection Of Floral Organ Development And Sterility In Sorghum Bicolor, Ashley R. Smith

Theses and Dissertations

Sorghum bicolor is a drought resistant cereal grain commonly grown for use in food, feed, fiber, and fuel production. Due to its versatility and modest sized genome it is poised to become an increasingly important research organism within the C4 plants. Sorghum produces spikelet pairs with one fertile sessile spikelet and one to two sterile pedicellate spikelets. One major area of interest in sorghum production is maximizing seed yield. While the importance of the grain is obvious there are several large gaps in the study of sorghum that prevent researchers and growers from maximum productivity. The first gap is that …

Mechanism Of Anti-Virulence Compound 187r Inhibiting Pseudomonas Aeruginosa Type Iii Secretion System, Liwei Fang

Theses and Dissertations

Antibiotics have been widely used for treating bacterial infectious diseases. However, the rapidly emerging of antibiotic resistance has dramatically decreased the efficacy of antibiotics and poses a serious worldwide crisis. In addition, the cell components serving as antibiotics’ targets are conserved in many different bacterial species, as a result, antibiotic treatments disrupt the host microbiota and negatively influence the hosts health condition. Therefore, new alternative strategies for fighting infectious diseases without causing antibiotic resistance and disturbing the host microbiota are needed. Type 3 secretion system (T3SS) is a highly conserved virulence factor presents in many different Gram-negative pathogens. It is …

An Assessment Of Bsa Protein Hydrogel Biocompatibility In The Vertebrate Intestinal Tract, Ryan Joseph Garde

Theses and Dissertations

The fields of biomedicine and pharmacology have a mission to design methods to treat disease while minimizing adverse side effects using novel drug delivery systems. In developing new therapeutic systems, it is crucial to test that drug delivery systems target pathological cells and tissue and is non-toxic in healthy tissue. One promising method for targeted drug delivery is the use of hydrogels as carriers. Here, we studied the effects of bovine serum albumin (BSA) hydrogel consumption to assess the potential for hydrogel use in treating intestinal disease via oral administration. We investigated intestinal architecture and cell populations following hydrogel treatments …

Novel Non-Invasive Technology For The Detection Of Thin Biofilm In Piping Systems (Phase - 1), Sachin Davis

Theses and Dissertations

Biofilms are formed when a group of cells of microorganisms stick to each other and often on a surface. The development of biofilm has been a major issue in many fields (medical field, food, chemical, and water industry are a few such fields). In the medical field alone, biofilm infections have reportedly cost over five billion USD in additional healthcare expenses. The food industry usually halts the operation of its plant eight hours, every day to ensure that their equipment and transportation channels are clean and free from any biofilm presence. Similarly, the water and chemical industry need to ensure …