Digital Commons Network^™

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 …

Identification And Characterization Of Salinity Tolerance Genes By Activation Tagging In Arabidopsis, Jawaher Alkahtani

Graduate Theses and Dissertations

Salinity often affects irrigated areas in arid and semi-arid regions of the world. The existence and accumulation of soluble salts in the soil layers limit the growth of crops essential for our food. Salt stress dramatically affects plant growth, plant development, as well as crop yield. Arabidopsis thaliana is the plant model that provides a comprehensive knowledge of plant development, genetics and physiology, and response to abiotic stresses such as salinity. The redundancy of genes due to duplication, even in the simple model genome of Arabidopsis, limits the value of knockout (KO) mutagenesis to provide complete information on gene function. …

Deception From Parents To Romantic Partners, Xiaoti Fan

Graduate Theses and Dissertations

Deception plays an important role in every type of relationship, particularly for the two most intimate relationships: parent-child and romantic. People usually learn behaviors and communication strategies from their parents and enforce or adjust them in other types of relationships based on various personal as well as social influences. The purpose of this study is to examine the strategies and motives young adults use with their parents and romantic partners when they convey deceptive messages, and explore how people apply patterns of deception from their parent-child relationships to their romantic relationships. In this study, two aspects of deceptive behavior are …

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 …

Modeling And Solution Approaches For Non-Traditional Network Flow Problems With Complicating Constraints, Negin Enayaty Ahangar

Graduate Theses and Dissertations

In this dissertation, we model three network-based optimization problems. Chapter 2 addresses the question of what the operation plan should be for interdependent infrastructure systems in resource-constrained environments so that they collectively operate at the highest level. We develop a network-based operation model of these systems that accounts for interdependencies among them. To solve this large-scale model, a solution approach is proposed that relatively quickly generates high-quality solutions to the problem.

Chapter 3 presents a routing model for a single train within a railyard with the objective of minimizing the total length traveled by train. The difference between this problem …

Characterization Of A Variant Of Tuberous Sclerosis Complex 2 And Its Interaction With Rheb, Sowmya Sivakumar

Graduate Theses and Dissertations

Protein-protein interactions are vital in maintaining proper function and homeostasis in cells. Some signaling pathways are regulated by G-proteins that work like switches to activate and deactivate pathways. Mutations in these proteins, their effectors or the interaction between proteins may cause dysregulation of signals that can lead to many diseases.

Rheb, Ras homology enriched in brain, is a Ras family GTPase that is vital in regulation of the mTOR (mammalian target of rapamycin) pathway that signals cell proliferation and growth. Due to the low intrinsic GTPase activity of Rheb, a GTPase activating protein (GAP), Tuberous Sclerosis Complex 2 (TSC2) down …

Determining The Effect Of Locally Delivered Bioactive Modulators On Macrophage Activation At The Implantation Site Of Different Biomaterials In Rats, Kamel Alkhatib

Graduate Theses and Dissertations

Altering the foreign body reaction by targeting macrophages has been of interest in the biomaterials field to improve the integration of longevity of implanted biomedical devices. The objective of this dissertation was to study the effect of locally delivered bioactive modulators on macrophage activation at the implantation site of different biomaterials in rats. Iloprost, a prostacyclin analog, was tested for its ability to direct macrophages to their pro-wound healing phenotype after the implantation of microdialysis probe in the subcutaneous space of male Sprague Dawley rats. This study showed that iloprost can shift macrophage activation states in vivo to the pro-wound …

Social Interactions Occurring During An Introductory College Of Agriculture Course, Brittany Renea Leek

Graduate Theses and Dissertations

With the development of the internet, today’s students no longer are confined to the resources only found in their classrooms or public libraries and have been given the ability to gain access to virtually unlimited quantities of information on the topics or events they are discussing in their class rooms and with their peers. The use of technology for communication and education is rapidly changing, but the challenges of technology-driven learning opportunities rest on questions of access and use. There is a need to determine whether students use these methods (i.e., technology based) to more prevalently communicate today. The primary …

Conformationally-Controlled Late-Stage Modifications For Sar Studies Of The C-3-Glcp Moiety Of Ipomoeassin F, Lucas Whisenhunt

Graduate Theses and Dissertations

The resin glycoside, ipomoeassin F has been shown to be extremely potent against multiple cancer lines (IC50 = 4.2-36 nM). However, the mechanism of action of this potent and complex natural product is still not fully understood. The α,β-unsaturated esters of the glucosyl moiety have been shown to be vital for the overall cytotoxicity of ipomoeassin F. Nevertheless, the importance of the tigloyl ester of the glucosyl moiety is still largely unknown. This work aimed to study the pharmacophore importance of the tigloyl ester by creating, an efficient, scalable, and flexible synthesis route for various analogs. The 18-linear step synthesis …

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 …

Association Mapping And Genomic Selection For Yield And Agronomic Traits In Soft Winter Wheat, Dennis Bulusan Lozada

Graduate Theses and Dissertations

Tools such as genome-wide association study (GWAS) and genomic selection (GS) have expedited the development of crops with improved genetic potential. While GWAS aims to identify significant markers associated with a trait of interest, the goal of GS is to utilize all marker effects to predict the performance of new breeding lines prior to testing. A GWAS for grain yield (GY), yield components, and agronomic traits was conducted using a diverse panel of 239 soft winter wheat (SWW) lines evaluated in eight site-years in Arkansas and Oklahoma. Broad sense heritability of GY (H2=0.48) was moderate compared to other traits including …

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, …

B. R. Wells Arkansas Rice Research Studies 2017, R. J. Norman, K. A. K. Moldenhauer

Arkansas Agricultural Experiment Station Research Series

No abstract provided.

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 …

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 …

Effect Of Morinda Citrifolia (Noni)-Enriched Diet On Hepatic Heat Shock Protein And Lipid Metabolism-Related Genes In Heat Stressed Broiler Chickens, Joshua Flees

Graduate Theses and Dissertations

Heat stress (HS) has been reported to alter fat deposition in broilers, however the underlying molecular mechanisms are not well-defined; therefore, the objectives of the current study were to: (1) determine the effects of acute (2 h) and chronic (3 wk) HS on the expression of key molecular signatures involved in hepatic lipogenic and lipolytic programs; and (2) assess if diet supplementation with dried Noni medicinal plant (0.2% of the diet) modulates these effects. Broilers (n=480 males, 1 d) were randomly assigned to 12 environmental chambers, subjected to two environmental conditions (HS at 35°C vs. thermoneutral condition [TN] at 24°C) …

Impact Of The Implementation Of Class-Wide Function-Related Intervention Teams On Adolescent Student Behavior, Dana Renee Speight

Graduate Theses and Dissertations

Disproportionality in discipline has been well-documented in the research literature (Achilles, McLaughlin, & Croninger, 2007; Losen & Gillespie, 2012; Gregory, Skiba, & Mediratta, 2017; Skiba, Peterson, & Williams, 1997). Students from diverse ethnic backgrounds and students with disabilities are removed from their classrooms more frequently than their Caucasian peers without disabilities (Losen & Gillespie, 2012). This disparate removal of students from diverse ethnic backgrounds and students with disabilities has spurned education stakeholders to call for removal of punitive policies and replacement with positive behavior interventions and supports. This study sought to evaluate the impact of Class-Wide Function-related Intervention Teams (CW-FIT) …

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: …

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 …

Membrane-Based Separation Processes For Treating High Salinity Produced Waters, Kamyar Sardari

Graduate Theses and Dissertations

Produced waters (PW) generated in the oil and gas industry within the United States often contain extreme levels of total dissolved solids (TDS). These high TDS waste streams need to be treated cost-effectively as the costs associated with the current management techniques can exceed 15 USD per barrel of discharged PW. Thermally and osmotically-driven membrane separation technologies can show promising potential for treating high TDS waste streams, as onsite low-grade waste heat may be used for their operation. In this dissertation, the application of membrane distillation (MD), forward osmosis (FO) and a hybrid FO-MD process for treating synthetic and actual …

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 …

Long-Term Focus Of Attentional Biases, Garrett Pollert

Graduate Theses and Dissertations

Prior research regarding attentional biases, or patterns of visual attention, have focused on attention over the initial second when exposed to pictoral food stimuli. This manuscript reviews the literature regarding attentional biases in overweight/obese individuals over this timeframe for the two previously defined components of attentional bias (attentional orientation and attentional maintenance). A new component is proposed, called “attentional re-engagement,” defined as the pattern of attentional shifts towards target stimulus types over longer periods of time. Overweight/Obese and Normal-weighted participants were recruited and engaged in an Extended Dot Probe task, wherein attentional orientation, maintenance, and re-engagement were assessed using the …

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 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 …

Anti-Inflammatory Effect Of Berry Essences, Inah Gu

Graduate Theses and Dissertations

Inflammation is one of defense reactions of our body tissues against harmful stimuli such as infection and tissue injury. However, it has been reported that chronic inflammation can lead to chronic inflammatory diseases including diabetes, cardiovascular diseases and cancer. This transition from acute to chronic inflammation state is usually induced by pro-inflammatory mediators and cytokines including nitric oxide (NO), prostaglandin E2 (PGE2), interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α), which accelerate the development of other chronic diseases. Accordingly, targeting these pro-inflammatory factors is one of the important roles for anti-inflammatory agents. For last two decades, researches about anti-inflammatory …