Digital Commons Network^™

Influence Of Ph And Acidic Side Chain Charges On The Behavior Of Designed Model Peptides In Lipid Bilayer Membranes, Venkatesan Rajagopalan

Graduate Theses and Dissertations

The molecular properties of transmembrane proteins and their interactions with lipids regulate biological function. Of particular interest are interfacial aromatic residues and charged residues in the core helix whose functions range from stabilizing the native structure to regulating ion channels. This dissertation addresses the pH dependence and influence of potentially negatively charged tyrosine, glutamic acid or aspartic acid side chains. We have employed GWALP23 (acetyl-GGALW5LALALALALALALW19LAGA-amide) as favorable host peptide framework. We have substituted W5 with Tyr (Y5GWALP23) and Leu residues with Glu (L12E, L14E or L16E) or Asp (L14D or L16D), and have incorporated specific 2H-labeled alanine residues within the …

Antimicrobial Inhibitory Activities Of Phenolic Extracts From Four Selected Soybean Hulls In Culture And Chicken Skin Model Systems, And Preliminary Ace-Inhibitory Activity, Rajaa Abdulkair Abutheraa

Graduate Theses and Dissertations

Soybean components provide health benefits to humans. Soybean hulls, a major by-product of the soybean processing industry consist of complex carbohydrates, proteins, lipids and polyphenols such as anthocyanidins, proanthocyanidins and isoflavones. The polyphenolic compounds in the hulls give them various colors such as black, brown, green, yellow or even a mottled appearance. Studies have reported different soybean varieties with varying total phenolic compounds in their seed hulls, which have antioxidant property. Phenolic extracts can be used as substitutes for synthetic antimicrobials and preservatives to assist in preventing the growth of pathogens such as Salmonella Typhimurium, E coli 0157:H7, and Campylobacter …

Exploring The Production Of Extracellular Matrix By Astrocytes In Response To Mimetic Traumatic Brain Injury, Addison Walker

Graduate Theses and Dissertations

Following injury to the central nervous system, extracellular modulations are apparent at

the site of injury, often resulting in a glial scar. Astrocytes are mechanosensitive cells, which can create a neuroinhibitory extracellular environment in response to injury. The aim for this research was to gain a fundamental understanding of the affects a diffuse traumatic brain injury has on the astrocyte extracellular environment after injury. To accomplish this, a bioreactor culturing astrocytes in 3D constructs delivered 150G decelerations with 20% biaxial strain to mimic a traumatic brain injury. Experiments were designed to compare the potential effects of media type, number of …

Quantitative Trait Loci (Qtl) For Salt Tolerance In Soybean And Physiological Response To Salt Stress During Early Growth Stage, Cindy Massiel Lopez Ramirez

Graduate Theses and Dissertations

Soybean is a major cash crop used as a source of high–quality protein and oil. Salt stress is one of the main abiotic stresses causing significant yield losses in soybean, which is considered a moderately salt–sensitive crop. Breeding selection is a promising strategy to improve salt tolerance as soybean germplasm display wide variation in response to salinity stress. However, the physiological and genetic mechanisms for salt tolerance are not quite clear. The discovery of novel QTL/genes associated with salt tolerance facilitates the development of tolerant cultivars through marker-assisted selection (MAS). The objectives of this study were: 1) identify/confirm QTL associated …

Effects Of Mars Regolith Analogs, Uvc Radiation, Temperature, Pressure, And Ph On The Growth And Survivability Of Methanogenic Archaea And Stable Carbon Isotope Fractionation: Implications For Surface And Subsurface Life On Mars, Navita Sinha

Graduate Theses and Dissertations

Mars is one of the suitable bodies in our solar system that can accommodate extraterrestrial life. The detection of plumes of methane in the Martian atmosphere, geochemical evidence, indication of flow of intermittent liquid water on the Martian surface, and geomorphologies of Mars have bolstered the plausibility of finding extant or evidence of extinct life on its surface and/or subsurface. However, contemporary Mars has been considered as an inhospitable planet for several reasons, such as low atmospheric surface pressure, low surface temperature, and intense DNA damaging radiation. Despite the hostile conditions of Mars, a few strains of methanogenic archaea have …

On The Air, On The Hill: The Story Of Radio At The University Of Arkansas, Blake Ryan Sutton

Graduate Theses and Dissertations

On the Air, On the Hill: The Story of Radio at the University of Arkansas is a film about the past, present, and future of radio on campus at the U of A. From the original campus station KFMQ in 1924, to the present day student station KXUA and the region’s NPR affiliate KUAF, the film explores not only the rich history of radio at the U of A, but also what the future holds for campus radio in the face of an ever-changing media landscape. The film draws from interviews with Fayetteville historians, as well as the major players …

Making A Gender Transition In Northwest Arkansas: Issues Of Access And Civil Rights In The Health Care System, April Michele Wallace

Graduate Theses and Dissertations

The transgender population in Northwest Arkansas has difficulty in finding quality, accessible healthcare for gender transition-related procedures and for basic medical needs as well. These difficulties stem in part from a complex combination of discrimination, lack of information and training for proper treatment and care. This study takes a look at what is and isn’t available to transgender people in Northwest Arkansas and why they travel to other states and countries to seek healthcare.

Scaffold And Tissue Based Therapies To Improve Skeletal Muscle Regeneration After Volumetric Muscle Loss, Benjamin Kasukonis

Graduate Theses and Dissertations

Volumetric muscle loss (VML) is an injury to skeletal muscle characterized by a loss of more than 20% of a muscles volume. The combination of the bulk loss of tissue, transection and separation of myofibers proximal and distal to the injury, loss of innervation and blood supply, and the depletion of muscle progenitor cells results in permanent fibrosis and functional deficits due to loss of contractile tissue. Scaffolds, cells, and engineered constructs have been explored as potential therapeutic interventions to induce myogenesis at the site of a VML injury in animal models, in addition to limited clinical trials. This dissertation …

Query Theory Applications: Choice Experiments Under Oath, Attendance To Attributes, And Genetically Modified Food Labeling Policy, Nathan Paul Kemper

Graduate Theses and Dissertations

In recent years, there has been an intensifying campaign by some stakeholders regarding concern over genetically modified (GM) foods in the U.S. As a result, the issue of labeling has entered into the federal agenda. This research uses Query Theory to provide a deeper understanding of the demand for GM foods and the preferences for GM policy. Query theory is first applied to the formation of hypothetical bias in the estimation of consumers’ willingness-to-pay. To address this, the honesty oath is used as an ex-ante technique to reduce hypothetical bias.

Paper one using Query Theory in a discrete-choice experiment (DCE) …

Immunotherapeutic Strategies To Reverse Tumor Associated Immunosuppression In Breast Cancer, Sruthi Ravindranathan

Graduate Theses and Dissertations

Heterogenous cancers such as breast carcinoma, would highly benefit from personalized vaccine approaches such as autologous tumor cell vaccines (ATCVs). By using cancer cells that are isolated from self, this approach has the potential to generate a polyclonal immune response against tumor antigens, that are specific to the individual. However, so far, ATCVs against breast cancers have not had any clinical success due to the poor immunogenicity of the malignant cells.

In this study, for the first time, we determined tumor derived G-CSF to play a major role in affecting immune response against breast cancer ATCVs. By using CRISPR/Cas9 genome …

Measuring Nonlinear Properties Of Graphene Thin Films Using Z-Scan Technique, Thekrayat Hassan Al Abdulaal

Graduate Theses and Dissertations

The nonlinear studies of two-dimensional (2D) nanomaterials, specifically graphene, are very significant since graphene is finding its usefulness in handling the enormous heat in nanoscale high-density power electronics. Graphene has emerged to be a promising nanomaterial as an excellent heat spreader due to its high thermal conductivity. However, the experimental nonlinear study of graphene materials and their application in developing future optoelectronic devices demands for more developed research.

The research objective is first to build a precise, and sensitive technique to investigate and understand the thermal nonlinear properties, including nonlinear refractive index (n2), nonlinear absorption coefficient (β), and thermo-optic coefficient …

A Study Of Short-Season Winter Cover Crops For Organic High Tunnel Production Systems, Luke Riley Freeman

Graduate Theses and Dissertations

This two-year study investigated short-season winter cover crops to improve soil quality and growth of subsequent vegetable crops in an organic high tunnel production system. Five winter cover crop treatments including a nontreated control, Austrian winter peas (Pisum arvense), bell beans (Vicia faba), mustard (Brassica juncea cv. Kodiak), and Daikon radish (Raphanus sativus var. longipinnatus) were grown in a high tunnel in a randomized complete block design from mid-November to mid-March, mowed and incorporated into the soil, and followed by a succession of vegetable crops including tomato (Lycopersicon lycopersicum, cv. ‘Plum Dandy’) and broccoli (Brassica oleracea var. italica, cv. ‘Bay …

Effect Of Light Intensity On Production Parameters And Feeding Behavior Of Broilers, Maurice Raccoursier Frost

Graduate Theses and Dissertations

This project was performed in two parts. The first was focused on light intensity as it affects performance. A randomized complete block design (RCBD) was performed. Broilers, Cobb 500 (n = 1584) were housed in 3 commercial houses (121.9 x 12.2 m). In each house birds were randomized and placed in 72 pens of 121.9 x 121.9 cm (22 bird/pen, males and females). All the treatment groups were provided with 24h light (L) during the first week and then 18L:6Dark (D) and 20 lux from day 7 to 14. The 3 intensity treatments of 5 lux (lx), 10 lx and …

The Role Of Organic Matter In The Fate And Transport Of Antibiotic Resistance, Metals, And Nutrients In The Karst Of Northwest Arkansas, Victor Lee Roland Ii

Graduate Theses and Dissertations

Organic matter (OM) in the environment acts as a nutrient, but may also act as a transport vector for harmful chemical compounds and bacteria. Acetate is a labile form of OM produced during fermentation in anaerobic lagoons used to store animal fecal-waste from concentrated animal feeding operations (CAFOs). Dry and liquid fertilizers from CAFOs pose a threat to groundwater by introducing excessive amounts of nutrients (e.g. OM, nitrate and ammonia), metals, and antibiotic compounds. In the epikarst of Northern Arkansas in the Buffalo River watershed additional input of labile dissolved organic carbon (DOC) from liquid CAFO waste-fertilizers was hypothesized to …

Eucalyptus In Kenya; Impacts On Environment And Society, Brandy M. Garrett Kluthe

Graduate Theses and Dissertations

Eucalyptus trees were introduced to Kenya a little over a century ago. European colonization along with the development of a railway system increased the demand for a fast growing wood source. The expansion of the tree across the fertile lands in Kenya raises concerns about the environmental impact on ecosystems where it has been introduced. These concerns include degraded soils, loss of water resources, co-introduction of ectomycorrhizal species, and allelopathy. Economic benefits to local landowners were also explored as well as the potential for large Eucalyptus woodlots to maximize the sequestration of CO₂ from the atmosphere. This was examined through …

Electricity Generation, Electricity Consumption, And Energy Efficiency In The United States: A Dual Climatic-Behavioral Approach, Christopher A. Craig

Graduate Theses and Dissertations

Much of the United States (US) has seen an increase in warm days, decrease in cool days, and increase in extreme weather events. These trends are projected to continue across much of the US and in turn increase the demand for electricity and subsequent greenhouse gas emissions. Ambitious energy efficiency (EE) programs are used across the US by energy utility organizations to reduce electricity demand and emissions. This study examined the impact of climatic variability on electricity consumption, as well as how pro-conservation interventions such as EE programs and experiential learning can be utilized to mitigate residential electricity consumption and …

Educational Technology And Innovation Capacity In Arkansas Public Schools, Allie Nicole Taylor

Graduate Theses and Dissertations

We all have high hopes for our educational system. As they stress the need for 21st century learning, governments recognize the importance of innovation and creativity in schools and invest resources to develop learning environments that foster these qualities. This thesis adapts Crosling, Nair, and Vaithilingam’s (2015) model to provide a framework for studying factors that contribute to a creative learning ecosystem (intellectual capital development, 21st century literacies, climate for innovation, and integrity of the system), the quality of the educational system, and the system’s innovation capacity. A survey of 126 Arkansas high school teachers, indicates that two variables, student’s …

Gender Representation And Occupational Portrayals In Primetime Television, Brittany Smith

Graduate Theses and Dissertations

This study examined gender representation and occupational portrayals on primetime television, in order to determine if gender-role stereotypes are still present throughout programming, and what progress, if any, has been made in comparison to previous studies. A content analysis was done on primetime programming airing during the fall of 2013 on ABC, CBS, NBC, Fox, and the CW, and analyzed gender, major and minor character, genre, occupation, and marital status. The findings of this study reveal that women are still underrepresented on-screen, as well as in prestigious occupations, especially when compared to their real world representation. This study also examined …

Physically Strong, Mentally Awake, And Morally Straight: Boy Scouts Of America As A Viable Prevention For Substance Use, David Thomas Rolfe

Graduate Theses and Dissertations

The purpose of this dissertation was to explore character-based recreation programs as a potential factor in youth drug use. Specifically, the study sought to find evidence that the Boys Scouts of America (BSA) might help prepare youth to avoid drug use or delay drug use to later in life. Using Positive Youth Development and Community Capital Theory as frameworks, the study explored character-based youth recreation as a holistic tool for engaging and nurturing youth. Positive Youth Development suggests that youth are best raised in a comprehensive and healthy environment. Community Capital Theory suggests that each community contains valuable resources that …

The Perception Of Bias By University Students With Access To An Education In Ethics: A Study Of The University Of Arkansas Walter J. Lemke Department Of Journalism And The Center For Ethics In Journalism, Kristen Coppola

Graduate Theses and Dissertations

The perception of media bias by students with an education in journalism and access to an education in journalism ethics was explored by juxtaposing two political articles covering the results of the 2016 Super Tuesday presidential primaries for both major parties and requesting students at different points in their education careers to rank them on six semantic differential items. Data was also gathered about the students’ knowledge and use of the Center for Ethics in Journalism. The results did not yield any support for previous research asserting that individuals are more inclined to perceive bias in articles with which they …

Microbes In Rough Rice – Prevalence, Growth Kinetics And Links To Dry Matter Loss, Supriya Thote

Graduate Theses and Dissertations

The prevalence of microorganisms on freshly-harvested long-grain hybrid, long-grain pureline, and medium-grain rice has not been elucidated. The first objective of this two-part study was to determine the relative prevalence of microbes on freshly-harvested, high moisture content rice of different types and cultivars. The total and surface aerobic plate counts (APC) and mold counts were determined in terms of log10 colony forming units per gram of rice (log10 CFU/g) for six rice cultivars over two years. In 2013, among harvested samples of all the studied rice cultivars, the long-grain hybrid cultivars had the lowest APC levels (M = 8.10, SD …

A Social Marketing Plan For The Lester C. Howick Animal Shelter, Joseph Michael Spiegelhoff

Graduate Theses and Dissertations

The Lester C. Howick Animal Shelter (Howick) is a non-profit organization serving Washington County, Arkansas and the Northwest Arkansas community. This thesis offers Howick a comprehensive Social marketing plan. The goal of the animal shelter is to increase the total number of cats and dogs adopted, increase the total amount of donations, and increase the number of volunteers helping at the facility and various events. In order to accomplish these goals for 2016, a Social marketing plan was developed through research on other non-profit organizations, other animal shelters, communication with the shelter employees, crafting a public service announcement (PSA), and …

Ironman: The Gordon Haller Story, Jacqueline Marie Antoinette Grajeda

Graduate Theses and Dissertations

The documentary film Ironman: The Gordon Haller Story takes a look at an ordinary man who accomplished the extraordinary feat of winning the first Ironman triathlon in 1978. Gordon Haller was born and raised in Oregon before a career in the United States Navy took him to Hawaii where he would eventually participate in the first Ironman competition. He is now a programmer analyst for Walmart, living with his wife in Bella Vista, Arkansas. This 26-minute film includes interviews with Haller as well as his wife, a friend and the director of development at the American Diabetes Association where he …

Listeria Monocytogenes Strain Variation: Starvation, Metabolism, And Macrophage Survival, Nathan A. Jarvis

Graduate Theses and Dissertations

Listeria spp. are often isolated from raw and processed food products. Listeria monocytogenes is responsible for death rates of 10 to 30% in immune compromised people; it can also infect a vast range of animals. There are numerous reports of poultry harboring or becoming infected with L. monocytogenes. First, this research assessed the ability of L. monocytogenes to replicate within chicken macrophages. Using the gentamicin-killing assay, a cell culture of chicken macrophage-like cells (HD11) were infected with two strains of L. monocytogenes individually (EGD-e and Scott A). Results show that unlike data on mouse macrophages, intracellular L. monocytogenes do not …

It's Not The Load That Breaks You Down, It's The Way You Carry It: An Examination Of The Relationship Between Negative Identity And Consumer Behavior, Cassandra Denise Davis

Graduate Theses and Dissertations

Research examining Social identity and consumer behavior often centers on groups with positive Social identities, exploring the influence of similar identities (i.e., shared values, shared gender, shared political affiliations, shared ethnicity…etc.) or desired identities (e.g., sports celebrities, actors, and actresses). For example, research has shown that people display an increased attention to identity-based stimuli following the activation of a Socially distinct identity (Forehand, Deshpandé, and Reed 2002) and that heightening the self‐importance of a consumer Social identity leads to a preference for identity-related brands (Reed 2004). An important but often overlooked aspect of the influence of Social identity on consumption, …

It's All About Me: How Self-Brand Connection And Social Media Interactivity Influence Purchase Intent, Shannon Taylor Mccarthy

Graduate Theses and Dissertations

Social media is ubiquitous and allows consumers to display identity by through possessions through posts, images, and interactions. The self is all the individual calls their own and is expressed outwardly through everything visible, including possessions, relationships, and interactions. They tell their story through the display of envy-inducing artifacts, and create a perfect, photoshopped life. Consumers seek a connection to positively viewed brands they feel are self-representative through interaction. This dissertation seeks to better understand consumer rationale for and gratification from online brand engagement and how that, in turn, impacts the brand. Three studies examined the effects of self-brand connection, …

Young Adult E-Cigarette Exposure: Implications For Policy And Prevention, Monica Page Daniel Dobbs

Graduate Theses and Dissertations

Objective. The purpose of this study is to examine factors associated with e-cigarette use among college students to better understand their behavior. Using Ajzen’s Reasoned Action Approach, this study sought to better understanding the influence of attitudes, Social norms, and perceived behavioral controls (PBCs) on college students’ intention to try e-cigarettes (even one puff) in the next 30 days.

Methodology. This study employed three phases for a mixed methods design that took place between December 2015 and April 2016. Phase 1 used Middlestadt’s salient belief elicitation procedure to capture responses through an open ended survey (n=58). Phase 2, a pilot …

Study Of Plasmonic Properties Of The Gold Nanorods In The Visible To Near Infrared Light Regime, Pijush Kanti Ghosh

Graduate Theses and Dissertations

Nanostructures of noble metals show unique plasmonic behavior in the visible to near-infrared light range. Gold nanostructures exhibit a particularly strong plasmonic response for these wavelengths of light. In this study we have investigated optical enhancement and absorption of gold nanorods with different thickness using finite element method simulations. This study reports on the resonance wavelength of the sharp-corner and round-corner rectangles of constant length 100 nm and width 60 nm. The result shows that resonance wavelength depends on the polarization of the incident light; there also exists a strong dependence of the optical enhancement and absorption on the thickness …

Comparisons Of Selected Household And Commercial Disinfectants Against Poultry Salmonella Isolates And A Survey Of Internal Parasites In Backyard Poultry In Arkansas, Kayleigh Moyle

Graduate Theses and Dissertations

Backyard and exhibition poultry have been gaining in popularity and as such there has been a large increase in the number of small flocks. As the interaction with poultry has increased, so has the opportunity for diseases and parasites, for both birds and people. One of the major zoonotic illnesses is caused by the bacteria Salmonella, which can be found in commercial and small flocks. Salmonella is the number 2 contributor of foodborne illnesses so its prevalence in commercial flocks is of high concern. Despite improved cleaning, disinfection, and biosecurity practices, there is still potential for disease outbreaks and infections …

Culinary Competence: Skills And Knowledge Assessment For Dietetic Students, Nancy Harris Buckley

Graduate Theses and Dissertations

Graduates of didactic programs in dietetics are entering internships with little cooking experience. The Food and Culinary Professionals’ Dietetic Practice Group (FCP DPG) has identified 11 core competencies that were developed as a recommendation to dietetic educators to include more culinary knowledge into existing programs. The purpose of this study was to determine if developing and incorporating experiential learning targeted to the competencies would increase dietetic students’ culinary skills and knowledge at a southern land-grant university. Food and Culinary Professionals’ DGP core competencies were used to guide the development of curriculum, experiential learning, and assessment in the Principles of Foods …