Digital Commons Network^™

Bioavailability Of Bioactive Compounds, Wing Shun Lam

Graduate Theses and Dissertations

Arachidin-1 (Ara-1) and arachidin-3 (Ara-3) are stilbenoids found in hairy peanut roots, which have been shown to possess similar, if not higher, efficacy in biological activities when compared to nonprenylated analogs such as piceatannol and resveratrol. Blackberry essences are concentrated volatiles, which are characterized by low molecular weight, lipophilic properties, and have also been demonstrated to have health benefits. As interest in dietary bioactive compounds functional ingredients increase, more emphasis has been placed on identifying which compounds have high efficacy as well as bioavailability. The ability of a compound to exert its health promoting effects depends on its bioavailable dose, …

Dissection Of Soil Waterlogging Tolerance In Soft Red Winter Wheat Using Genomic Approaches, Marlovi Andrea Acuna-Galindo

Graduate Theses and Dissertations

Genomic methods including genome wide association analysis (GWAS), genomic selection (GS) and RNA-seq allow for faster selection of superior breeding lines and for identification and resolution of candidate genes. A panel of 240 soft red winter wheat (Triticum aestivum L.) cultivars and breeding lines were subjected to soil waterlogging stress over two seasons at Stuttgart, AR and St. Joseph, LA, US. Total concentrations of P, K, Ca, Mg, Mn, Fe, Al, B, Cu, Na, S and Zn were determined in wheat shoots post-waterlogging using inductively coupled plasma spectroscopy. Yield components kernel number per spike (KNPS), kernel weight per spike (KWS) …

Flow Regime Influences On Stream And Riparian Soil Carbon Dynamics In The Ozark Highlands And Boston Mountains Of Arkansas, Allyn Dodd

Graduate Theses and Dissertations

The natural flow regime exerts primacy over lotic ecosystem patterns and processes. However, little work has examined the influence of flow regime on instream and riparian carbon (C) dynamics in minimally-impacted, temperate forested systems. To date, most research efforts have focused on characterizing C movement and transformations across biomes and land use categories; however, flow regime represents an overlooked, finer level of detail that may drive differences in ecosystem function. My dissertation objective was to measure C fixation and movement within and across multiple environmental spheres (e.g. within stream channels, between stream surfaces and the atmosphere, and from riparian soils …

Determinants Of Hydration In Children: The Role Of Physical Activity And Parental Dietary Habits, Hyun-Gyu Suh

Graduate Theses and Dissertations

PURPOSE: The purpose of these studies was 1) to examine the factors that influence the water intake in children and 2) to identify the optimal time window to assess hydration status that would be equivalent to 24-hour urine sample in children. METHODS: Study 1: Data for 200 parents (age:3-13y, female:62%, BMI:28.4±7.0kg∙m-2) and 200 children (age:7.5±2.9y, female:44%, BMI:17.7±3.9kg∙m-2) were recruited. Subjects recorded their fluid and food consumption on the 2-day diary, and food data were analyzed by using the Nutrition Data System for Research (NDSR) program. Physical activity levels were assessed with the International Physical Activity Questionnaire (IPAQ). All urine samples …

Molecular Survey For The Honey Bee Trypanosome Parasites Crithidia Mellificae And Lotmaria Passim, Mary-Kate Williams

Graduate Theses and Dissertations

Honey bee populations have been fluctuating within recent years. No one cause has been attributed to colony fluctuations due to the theory that multiple stressors interact with one another to impact colony health. Consequently, microorganisms such as internal parasites of honey bees have been understudied as a contributor to colony health decline.

Molecular diagnostics were utilized to detect the presence of two honey bee trypanosome parasites, Crithidia mellificae and Lotmaria passim, in managed and feral honey bee populations from eight states in the United States (USA). Because studies on trypanosome infections are lacking in the USA, it is important to …

Investigation Of Bacterial Taxa As Biomarkers Of Fescue Toxicosis And Heat Stress In Grazing Beef Cows, Sarah Katherine Chewning

Graduate Theses and Dissertations

Fescue toxicosis in grazing beef cattle is caused by consumption of Ergot alkaloids associated with tall fescue (toxic fescue) and is responsible for substantial economic loss to the U.S. beef industry. Cattle consuming toxic fescue suffer adverse physiological responses, such as: hyperthermia, increased respiration rate (RR), poor reproduction and growth performance. Other adverse responses to fescue toxins include the retention of a winter hair coat and vasoconstriction in the extremities, which can lead to tissue necrosis. Identifying cattle with reduced susceptibility to fescue toxins would allow for efficient use of fescue pastures; thus, the objectives of this thesis was to: …

Gold Nanoparticles For Stem Cell Delivery In Myocardial Infarction: Analysis Of Toxicity And Development Of A Cell Culture Platform For Use In An In-Vitro Model Of Mi-Associated Ischemia/Reperfusion, Jeffrey Curran Henson

Graduate Theses and Dissertations

In this work, the potential for PEGylated gold nanoparticles for use as a platform for stem cell delivery in treatment of myocardial infarction (MI) is preliminarily investigated. Cardiovascular disease is currently the leading cause of death worldwide, with majority of mortality resulting from coronary artery disease and associated MI. The ensuing ischemic conditions resulting from MI cause substantial heart muscle tissue loss and scarring in the heart. Adverse tissue remodeling creates a significant loss in heart function that can result in the formation of cardiac hypertrophy, ventricular dilation and arrythmias. The long-term prognosis of patients who have suffered MI is …

Stratigraphic Evaluation Of The St. Joe-Boone Boundary Interval, Kinderhookian-Osagean Series, Lower Mississippian System, Tri-State Region, Southern Midcontinent, Forrest Dalton Mcfarlin

Graduate Theses and Dissertations

The Lower Mississippian interval comprises a single, third-order, eustatic cycle subdivided lithostratigraphically into the St. Joe Limestone (Hopkins 1893) and overlying Boone Formation (Branner 1891, Simonds 1891) with type areas in northern Arkansas. Coeval, homotaxial limestones occur in adjacent southwestern Missouri and northeastern Oklahoma. Missouri formation names for the St. Joe interval are recognized in Arkansas as members (ascending order): Bachelor, Compton, Northview, Pierson. The Boone interval in Missouri is represented by the (ascending order): Reeds Spring, Elsey, Burlington-Keokuk undifferentiated, but utilization of those names in Arkansas is problematic. in northern Arkansas, the Boone Formation is subdivided into informal lower …

Estimating Watershed Mercury Contribution To Lake Fort Smith State Park, Arkansas, Usa, William Miles Harmon

Graduate Theses and Dissertations

Mercury contamination associated with human activities poses global human health and environmental risks. A fish-consumption advisory has been in effect at Lake Fort Smith in central west Arkansas for more than a decade due to observed methylmercury concentrations in fish tissue. Lake Fort Smith is an important municipal drinking water supply and recreational resource. Water samples from the majority contributing tributary stream, Frog Bayou creek, were collected periodically, under differing hydrologic conditions in order to quantify the allochthonous mercury load delivered to the lake. Temperature, specific conductance, and turbidity data were collected and used to estimate dissolved organic carbon, methylmercury …

Assessment Of A Nutritional Rehabilitation Model In Two Modern Broilers And Their Jungle Fowl Ancestor: A Model For Better Understanding Childhood Undernutrition, Mikayla Baxter

Graduate Theses and Dissertations

The World Health Organization, estimated that 22.9% of children under the age of 5 are stunted. The etiology of stunting is multifactorial and is associated with poor linear growth, villous atrophy, dysbiosis, and increased intestinal permeability. Inclusion of rye in poultry diets induces nutrient deficiencies and increases intestinal permeability, dysbiosis and decreases growth rates. The objective of this dissertation was to determine if chickens consuming a rye based diet exhibited a similar pathophysiology of stunted children to develop a relevant animal model. Therefore, early or late phase malnutrition was induced determine the effects of malnutrition on performance, bone mineralization, intestinal …

Dehydration, Muscle Damage, And Exercise In The Heat: Impacts On Renal Stress, Thermoregulation, And Muscular Damage Recovery, Cory L. Butts

Graduate Theses and Dissertations

Purpose: The purpose was to identify the combined influence of dehydration, muscle damage, and exertional hyperthermia on biological markers of acute kidney injury and renal function. We also investigated the effects of performing muscle damaging exercise during mild hypohydration on muscle damage biomarkers and muscular strength recovery. Methods: Eighteen recreationally-active males (age 24 ± 5 y, body fat 17.3 ± 6.2%) completed a familiarization visit and two experimental trials separated by ≥28 days. The two experimental conditions consisted of either euhydration (EU; maintaining hydration, -1.2 ± 0.8%) or hypohydration (HY; restricting fluid consumption for 24 hours prior to and during …

High-Sn-Content Gesn Alloy Towards Room-Temperature Mid Infrared Laser, Wei Dou

Graduate Theses and Dissertations

Si photonics is a rapidly expanding technology that integrates photonic circuits onto a Si substrate. The integration of Si electronics and photonics has been a successful technology for a wide range of applications. Group-IV alloy GeSn has drawn great attentions as a complementary metal–oxide–semiconductor compatible optoelectronic material for Si photonics. The devices based on GeSn alloy could be monolithically integrated into well-established and high-yield Si integrated circuits, which is favorable for chip-scale Si photonics featuring smaller size, lower cost, and higher reliability.

The relaxed GeSn with high material quality and high Sn composition is highly desirable to cover mid-infrared wavelength. …

Chemical Strategies For Drug Development Of Fucose-Truncated Ipomoeassin F Analogues, Melissa Hirsch

Graduate Theses and Dissertations

Natural product synthesis has many applications in the field of chemical biology, due to the protein binding affinity to the complex three-dimensional structure. However, synthetic and structure-activity relationship studies concerning certain drug targets are scarce. For example, members of the ipomoeassin family have exhibited anti-cancer properties, but cost-effective optimization of these compounds has not yet been extensively studied. Ipomoeassin F, a natural glycoresin isolated from the leaves of the Ipomoea squamosa plant in the Suriname rainforest, has shown high cytotoxicity, with IC50 values measured at the low nanomolar range. Two studies by Postema and Fuerstner have outlined synthesis pathways for …

Assessing A Peer Mentor Program In An Honors College Of Agriculture, Isabel Whitehead

Graduate Theses and Dissertations

The purpose of the study was to assess mentees’ experiences in a peer mentor program in an honors college of agriculture and to determine which factors impact mentees’ ability to relate to their peer mentor based on the theory of homophily and interpersonal attraction. Colleges of agriculture are encouraged to examine which determinants impact students’ decisions to enter agri-science programs, what draws students to postsecondary agricultural programs, and to try recruiting underserved individuals into higher education to fulfill open employment opportunities for diverse, skilled, and globally competent individuals (Goeker, et al., 2015; Stripling & Ricketts, 2017). Peer mentoring is often …

Opto-Thermal Characterization Of Plasmon And Coupled Lattice Resonances In 2-D Metamaterial Arrays, Vinith Bejugam

Graduate Theses and Dissertations

Growing population and climate change inevitably requires longstanding dependency on sustainable sources of energy that are conducive to ecological balance, economies of scale and reduction of waste heat. Plasmonic-photonic systems are at the forefront of offering a promising path towards efficient light harvesting for enhanced optoelectronics, sensing, and chemical separations. Two-dimensional (2-D) metamaterial arrays of plasmonic nanoparticles arranged in polymer lattices developed herein support thermoplasmonic heating at off-resonances (near infrared, NIR) in addition to regular plasmonic resonances (visible), which extends their applicability compared to random dispersions. Especially, thermal responses of 2-D arrays at coupled lattice resonance (CLR) wavelengths were comparable …

A Multimodal Assessment Of Disgust In Response To Traumatic Event Reminders Among Adolescents, Teah-Marie R. Bynion

Graduate Theses and Dissertations

The majority of youth will report traumatic event exposure by the time they reach adulthood. Research suggests exposure to such events is linked to myriad negative outcomes. Not all traumatic events are alike, however; evidence suggests that, compared to non-interpersonal events, interpersonal events in which another person intentionally perpetrates harm are linked to elevations in the likelihood of negative outcomes, including posttraumatic stress disorder (PTSD). One reason for this discrepancy is that interpersonal traumatic events may elicit greater levels of disgust. However, this is a very under-developed research base, no study has examined this question among youth. The current study …

Evaluation Of Acetochlor And Other Very-Long-Chain Fatty Acid-Inhibiting Herbicides In Arkansas Rice, Michael E. Fogleman

Graduate Theses and Dissertations

The prevalence of herbicide resistance and lack of effective management options for controlling problematic weeds such as barnyardgrass and weedy rice in Arkansas rice production has led to exploration of alternative herbicide sites of action (SOA). Very-long-chain fatty acid (VLCFA)-inhibiting herbicides are not currently labeled for use in U.S. rice production but have been used with success in other row crops and in rice production in Asia. Based on preliminary research, rice tolerance and weed control were evaluated following various application timings and rates of acetochlor and pethoxamid, in addition to several other VLCFA-inhibiting herbicides. Rice tolerance to acetochlor was …

Evaluation Of A Solar Powered Variable Flow Tail Water Recovery System For Furrow Irrigation, Vaishali Kandpal

Graduate Theses and Dissertations

Furrow irrigation is a very common irrigation method for growing crops like soybean, cotton and corn in Arkansas. A major portion of this irrigation water is lost as runoff from the field significantly reducing the irrigation application efficiency. There are various methods of improving irrigation efficiency and one of the methods is using tail-water recovery. A tail-water recovery system utilizes tail-water recovery ditches or pits to collect tail-water which can be re-used for irrigation. However, this method is very labor intensive and has been found to be economically non-feasible for some farms in the past research studies. In order to …

Comparative Microbial Community Dynamics In A Karst Aquifer System And Proximal Surface Stream In Northwest Arkansas, Josue Rodriguez

Graduate Theses and Dissertations

Northwest Arkansas has well-developed karst systems, with numerous sinking streams and springs. Karst conduits make it easy for contaminants to enter groundwater systems, degrading the water quality and destroying fragile karst ecosystems. With the increase of urbanization, potential threats in the form of fecal contamination may prove to be more of a problem. The purpose of this research is to compare the difference between microbial communities within two different settings, a karst aquifer and a surface stream. The microbial communities within Blowing Spring Cave and Little Sugar Creek were detected and identified in water and sediment samples. Samples were also …

Effects Of Fire Season And Temperature On A Spotted Knapweed (Centaurea Stoebe) Infested Grassland, Zachery T. Pitman

Masters Theses

Invasive species, including the non-native forb Centaurea stoebe (spotted knapweed), constitute an imminent threat to degraded and restored native prairies. Considering the major threat that C. stoebe poses to imperiled prairie ecosystems, I examined the effectiveness of fire as a control agent of C. stoebe and (±)-catechin. I conducted a 2-year experiment in part of a restored tallgrass prairie community at Pierce Cedar Creek Institute in Barry County, Michigan between May and August of 2016 and 2017. My experiment consisted of individually burning 60 1-m² plots with a propane torch to achieve high (316° C) and low (103° C) temperatures …

Occupancy And Detection Of Yellow Perch In Great Lakes Coastal Wetlands, Kaitlyn M. Dykstra

Masters Theses

Accurately estimating the distribution of a species is important for managing sustainable populations of fishes. The Yellow Perch Perca flavescens is an important sport fish in the Great Lakes region and one of the most abundant fishes in Great Lakes coastal wetlands, which they commonly use for spawning and nursery habitat. Many fisheries management decisions are based on results from sampling fish assemblages, but these methods rarely account for incomplete detection (i.e., presence of a species that is not detected by sampling), which could create biased results. We applied the method of occupancy modeling, which accounts for incomplete detection, to …

Effects Of Eicosapentaenoic Acid (Epa) On Mouse Endothelial Cell Health, Spencer C. Pageau

Masters Theses

Cardiovascular disease is the number one killer of adults in the US (~800,000 lives every year:1 in 3 deaths). Evidence suggests omega-3 fatty acids like eicosapentaenoic acid (EPA), found in fish oils, reduce the risk of developing cardiovascular diseases. Many of these diseases are caused by atherosclerotic plaque development in vessels due to endothelial cell damage initiating inflammatory responses. Recent work argues omega-3 fatty acids stimulate anti-inflammatory responses by binding to Free Fatty Acid (FFA) receptors. Inflammatory responses in endothelial cells alter the expression of many proteins that affect the function of those cells. In particular, gap junction protein (connexin: …

The Effect Of Alpha-Linolenic Acid (Ala) On Endothelial Cell Expression Of Connexin43, Benjamin Pichette

Masters Theses

Atherosclerosis is the leading cause of cardiovascular diseases like myocardial infarctions and strokes. The formation of these atherosclerotic plaques occurs through localized inflammatory responses in blood vessels. Epidemiological evidence suggests omega-3 fatty acids (FAs) decrease vascular inflammation. The omega-3 FAs eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) reduce inflammation through pathways that may include the free fatty acid-4 (FFA-4) receptor. While EPA and DHA are well studied, less is known about the essential omega-3 FA from which they are synthesized: alpha-linolenic acid (ALA). Thus, this study will investigate whether ALA can activate the FFA-4 receptor and thereby contribute to anti-inflammatory …

Impacts Of Sediment Dredging On Phosphorus Dynamics In A Restored Riparian Wetland, Kimberly Oldenborg

Masters Theses

Global reductions in biodiversity and water quality are having major consequences for ecosystem health and societal well-being. The restoration of riverine floodplains and wetlands provides an ideal opportunity to increase biodiversity and water quality because their hydrologic connectivity to adjacent streams and rivers promotes the formation of heterogeneous habitat while also facilitating their functioning as a nutrient sink, in general. However, many historic floodplains and riverine wetlands have been drained for the creation of agricultural land, resulting in an accumulation of nutrients in the soils. Therefore, restoration practices that hydrologically reconnect former agricultural land to an adjacent stream or river …

Assessment Of Invasive Gypsophila Paniculata Control Methods In The Northwest Michigan Dunes, Emma K. Rice

Masters Theses

Gypsophila paniculata is an invasive species in Michigan’s northern lower peninsula and a problem invasive in much of the northern United States and Canada. Gypsophila paniculata readily outcompetes native plants in sandy, well-drained soils due to its deep taproot, which allows access to scarce resources. It reproduces and disperses mainly by seed, but the phenology of seed maturation is poorly understood. Gypsophila paniculata is of particular concern in lakeshore dunes because the areas where it is most dense are also populated by several endemic and threatened species. Despite many years of intensive management, high densities of G. paniculata persist …

Estimating Components Of Stream Metabolism Using The Free Water Dissolved Oxygen Method, Jay R. Zuidema Jr.

Masters Theses

Stream ecosystem metabolism is commonly measured in stream ecology studies in order to understand the functioning of the stream ecosystem and as an indicator of stream health. One common method for gathering the time series data required to estimate stream metabolism is the free water dissolved oxygen method, which involves measuring dissolved oxygen in freely moving water. This is accomplished by taking measurements at a single location (one-station monitoring method) or at two locations (two-station monitoring method). In conjunction with these data, a process-based model of dissolved oxygen dynamics is used to estimate gross primary production, respiration, and net production. …

Investigating Erosion And Ecological Impacts To An Urban Coldwater Stream Using Multiple Techniques, Daniel T. L. Myers

Masters Theses

Sediment pollution is a major cause of stream degradation. Our objectives were threefold. First, we assessed the impacts of environmental stressors on the structure of fish and macroinvertebrate communities across a gradient of agricultural to urban land cover in a coldwater tributary of the Grand River, Michigan, USA called Indian Mill Creek. We found that instream woody debris, streambed substrate, riffle and pool habitat variability, and riparian conditions affected aquatic macroinvertebrates along an agricultural to urban land cover gradient. We also found that variation in fish community assemblage was driven largely by stream flow and temperature regimes and could be …

Environmental Factors Influencing Amphibian Community Assemblage In Dune Wetlands On The Lake Michigan Coast, Alex H. Jouney

Masters Theses

Wetlands in dune landscapes provide important breeding habitat for amphibians along the Lake Michigan Coast. Unfortunately, these unique habitats and the corresponding amphibian metapopulations are understudied and threatened. We assessed amphibian species richness and terrestrial habitat type in 16 permanent and ephemeral wetlands along the coast of Lake Michigan in Grand Haven, MI. Wetland area, terrestrial habitat type, depth, hydroperiod, shade, and degree of isolation were measured from April to September of 2017. Nine species of amphibian were found; Green Frog (Rana clamitans melanota) and Spring Peepers (Pseudacris crucifer crucifer) were most abundant and Fowlers Toad …

Genetic Structure Of Invasive Baby’S Breath (Gypsophila Paniculata) Populations In A Michigan Dune System, Hailee B. Leimbach-Maus

Masters Theses

Invasive species can reduce biodiversity of a system by outcompeting native species for resources, changing the physical characteristics of a habitat, and altering natural disturbance regimes. Coastal sand dune ecosystems are dynamic with elevated levels of disturbance, and as such they are highly susceptible to plant invasions. The topography, geographic distribution of preferred habitat, and disturbance regime in an ecosystem can influence where an invasive plant becomes established, its dispersal patterns, and how densely it grows. One such invasion that is of major concern to the Great Lakes dune systems is baby’s breath (Gypsophila paniculata). The invasion of …

Evidence For Exaptation Of The Marchantia Polymorpha M20d Peptidase Mpilr1 Into The Tracheophyte Auxin Regulatory Pathway, James Campanella, Stephanie Kurdach, Joy Bochis, John V. Smalley

Department of Biology Faculty Scholarship and Creative Works

Auxin homeostasis is tightly regulated by several mechanisms, including conjugation of the hormone to specific moieties, such as amino acids or sugar. The inactive phytohormone conjugate is stored in large pools in plants and hydrolyzed to regain full activity. Many conjugate hydrolases (M20D metallopeptidases) have been identified and characterized throughout the plant kingdom. We have traced this regulatory gene family back to liverwort (Marchantia polymorpha), a member of the most ancient extant land plant lineage, which emerged approximately 475 million years ago. We have isolated and characterized a single hydrolase homologue, dubbed M. polymorpha IAA-Leucine Resistant1 (MpILR1), from liverwort. MpILR1 …