Digital Commons Network^™

Improvements In Microdialysis Sampling Extraction Efficiency Using Recycled Flow, Justin Cole Deaton

Graduate Theses and Dissertations

Incomplete recovery during microdialysis sampling is hindering important research in neurology, proteomics, and immunology. Although the current generalized solution, decreasing volumetric flow rates (Q), has been and will remain to be a useful strategy it has reached it's a physical limitation due to evaporation at the collection site. Consequently, many important signaling molecules, such as signaling proteins, remain difficult to study. It is more fundamental to consider relative recovery as a function of the interaction time between the perfusate and the environment surrounding the probe.

In this work an increase in relative recovery was predicted by a mathematical model. Using …

Dark Green Color Index As A Method Of Real-Time In-Season Corn Nitrogen Measurement And Fertilization, Upton Siddons

Graduate Theses and Dissertations

Corn (Zea mays L.) requires higher rates of nitrogen fertilizer than any other major U.S. crop partly because N fertilizers are subject to loss through various mechanisms. Because of this, corn may suffer from inadequate nitrogen fertilization or producers may over-apply nitrogen to compensate for early-season nitrogen losses. A timely, accurate, and precise method for measuring in-season corn N status is needed to allow producers to keep nitrogen use efficiency high within a growing season.

Using appropriate software, hue, saturation, and brightness values of digital images can be combined in a dark green color index (DGCI) which is closely associated …

Glyphosate-Resistant Palmer Amaranth (Amaranthus Palmeri) In Arkansas: Resistance Mechanisms And Management Strategies, Griff Michael Griffith

Graduate Theses and Dissertations

Since 2000, there have been thirteen weed species confirmed resistant (R) to glyphosate in the United States, six of those resistant species are present in Arkansas. The goal of this research was to confirm and to determine the level of resistance in two R Palmer amaranth biotypes from Mississippi (MC-R) and Lincoln (LC-R) Counties, Arkansas, and one susceptible (S) biotype from Clarendon County, South Carolina, which had never been exposed to glyphosate. Shikimic acid concentration over time was significantly greater in the S biotype than both the MC-R and LC-R biotypes. The lethal dose required to kill 50% (LD_{50 …}

Relationship Of Lactate Dehydrogenase & Prolactin Genotypes To Immune Function, Growth, And Composition Of Replacement Heifers Grazing Tall Fescue, Christina Marie Turner

Graduate Theses and Dissertations

Objectives of this research were to determine effects of LDH enzymatic activity and circulating PRL on immune response, growth, composition, and reproduction, and to determine the effects of single nucleotide polymorphisms of LDH and PRL on immune function, growth and carcass traits, cyclicty, and fecundity of replacement heifers grazing endophyte infected tall fescue. Eighty-nine Angus based heifers had physical and ultrasound measurements along with blood samples collected at weaning, yearling, and prebreeding. Estrus detection was conducted for 10 d post each collection period, except prebreeding. Pregnancy status was verified after AI and again after bull removal. Heifers were maintained on …

Proteomic Studies Of The Influenza Virus-Human Cell Interactions: The Responses Of Host Cell Protein Expression To Viral Infection And The Novel Host Proteins That Interact With Virus Protein Ns1, Yimeng Wang

Graduate Theses and Dissertations

Influenza A viruses (IAVs) continue to be a threat to human health. Despite extensive studies, the mechanisms underlying the IAVs-host interactions during IAV infection remain elusive. We employed quantitative proteomic methods to systematically explore the host cell protein expression responses to IAV infection and examine the function of a critical IAV protein called NS1 by identifying its host binding partners. Specifically, we used a 2-dimentional gel electrophoresis (2-DE) based proteomic method to screen host proteins whose expression was substantially altered by IAV. One critical protein named IκB kinase-gamma (IKKγ) was found to be significantly down-regulated during IAV infection. Functional studies …

Expression, Production, And Purification Of Novel Therapeutic Proteins, Mckinzie Shea Fruchtl

Graduate Theses and Dissertations

Interest in the production of recombinant proteins consisting of collagen binding domain (CBD) fused to a bioactive material has increased due to the targeting/attachment capabilities of CBD. For example, CBD fusions can be applied to the reversing of bone density loss and the repair of the eardrum, specifically, by choosing an appropriate fusion partner (parathyroid hormone or epidermal growth factor). The production of CBD fusions was examined using batch and fed-batch culturing of Escherichia coli to express the fusion proteins, and affinity chromatography to isolate the final product.

Different medium formulations, feeding strategies, and induction methods were tested in order …

Litter Conditioning Is Differentially Affected By Leaf Species, Phosphorus Enrichment, And Light Availability, Erin E. Scott

Graduate Theses and Dissertations

Anthropogenic enrichment of nitrogen and phosphorus is one of the most pervasive and detrimental threats to aquatic ecosystems worldwide. In streams that rely on allochthonous basal food resources, such as leaves, nutrient pollution can result in altered food quality and decreased carbon (C) standing stocks. However, the magnitude and mechanisms of this change in quality are poorly understood. Laboratory microcosm studies were conducted to 1) quantify the response of litter C:P to a gradient of phosphorus (P) enrichment (0, 0.05, and 0.5 mg SRP/L) across leaf species with variable levels of degradability (sugar maple and oak), and 2) quantify the …

Comparing The Impact Of Traditional And Modeling College Algebra Courses On Student Performance In Survey Of Calculus, Jerry West

Graduate Theses and Dissertations

Students in higher education deserve opportunities to succeed and learning environments which maximize success. Mathematics courses can create a barrier for success for some students. College algebra is a course that serves as a gateway to required courses in many bachelor's degree programs. The content in college algebra should serve to maximize students' potential in utilizing mathematics and gaining skills required in subsequent math-based courses when necessary. The Committee for Undergraduate Programs in Mathematics has gone through extensive work to help mathematics departments reform their college algebra courses in order to help students gain interest in the utilization of mathematics …

Efficacy Of Selected Disinfectants Against Salmonella Isolates From Broiler Breeders, Arslan Aslam

Graduate Theses and Dissertations

Salmonella have been causing huge losses in the poultry industry and have been a major cause food borne illness for many years. Salmonella infections in humans from poultry have been increasing. Good hygiene and biosecurity measures can reduce the incidence of Salmonella infections at poultry farms. Disinfection is a most important measure taken to prevent Salmonellosis in poultry. This research was conducted to determine the efficacy of 12 disinfectants against seven Salmonella isolates in the presence and absence of organic matter. A bacterial solution of a specific optical density value was prepared and .05x, .1x and .2x concentrations of disinfectants …

Principal And Teacher Beliefs About Leadership Implications For Student Performance, Jerri Cherita Jackson

Graduate Theses and Dissertations

The goal of this study was to examine whether the leadership style of principals affects teacher and student performance. The study includes an elementary, middle, and high school principal along with two teachers from each school who worked at schools that were in good standing from 2007-2011. Each school made adequate yearly progress (AYP) each year according to the No Child Left Behind Status History Report. This study examined one over arching research question: What do principals and teachers say about school and schooling? Data for this study was gathered through principal interviews, teacher interviews, and the results of an …

Evaluating The Formation Of Bacterial Chondronecrosis With Osteomyelitis In Broilers Raised On Portable Wire Floor Models, Alex David Gilley

Graduate Theses and Dissertations

Rearing birds on wire flooring has proven to be an effective method for consistently triggering significant levels of lameness in broilers, and while the wire flooring model has been proven effective, more mobile wire floor models have been developed to compliment the facility management conditions within commercial genetic selection programs. The mobile wire floor models have been titled "speed bumps", and through previous evaluation have resulted in significantly higher levels of lameness in broilers compared to litter floor shavings. The current experiment contains two studies (studies 1 and 2). Both studies involved comparing leg weakness between broiler strains; while in …

Effects Of Ergot Alkaloids And Bovine Bodily Fluids On Cytochrome P450 Activity, Nicholas Scott Ezell

Graduate Theses and Dissertations

This thesis evaluates the Promega^TM P450-Glo assay (Promega^TM V9800) as a tool for quantifying ergot alkaloid concentration. Current techniques used for detection of ergot alkaloids are slow and expensive, do not detect all ergot alkaloids, or are not effective on bovine bodily fluids. The first study was conducted to determine effects of commercial ergot alkaloids (n = 6; 0 - 400 μM) on the Promega^TM P450-Glo assay. Cytochrome P450 (CYP450) activity in assay had a differential response to each ergot alkaloid and concentration. As concentrations of ergotamine, dihydroergotamine, ergocornine, and ergocryptine increased CYP450 activity was inhibited (P …

Learning Experiences And Perspective Transformation In Evangelical Faith-Based Adult Nonformal Education Programs, Philip Gerke

Graduate Theses and Dissertations

The study adapted an existing instrument to examine perspective transformation and its associated factors in participants of evangelical faith-based adult nonformal education in the Midwestern United States. Stratified random one-stage cluster sampling of 11 churches produced a nonprobability sample (N = 597) that was significantly (p < .05) different from the population of the geographical location of the study. An 86% majority self-reported a level of agreement or stronger of perceived transformation of perspectives, but differences predicted by gender were insignificant. The difference in perceived perspective transformations between respondents aged 40-59 that had the highest levels and respondents aged 60 and above that had the lowest levels was significant. The factors of influential individuals, personal reflection, and thought-provoking learning assignments significantly predicted all four factors of perspective transformation; the Writing Assignment factor was a significant negative predictor of only the Perception of Change factor, and a significant positive predictor of only the Future Benefits factor. The study recommended that additional research on faith-based frames of reference and age category differences. The study also recommended that faith-based practitioners consider emphasizing transformative learning experiences and personal reflection in their programs for adults.

"An Ample Provision For Our Posterity": Transportation, Ceramic Diversity, And Trade In Historic Arkansas, 1800-1930, Katherine Rose Cleek

Graduate Theses and Dissertations

In this dissertation I present a method to study transportation using ceramic diversity and access to transportation infrastructure. Ceramic tableware richness, or the number of types present, is analyzed over time as a proxy for access to local transportation infrastructure at seven sites in Arkansas, dating from approximately 1800 to 1930. Previous efforts to look at trade in historical archaeology including Adams (1976), Riordan and Adams (1985), and Adams, Bowers, and Mills (2001) have not thoroughly assessed transportation as a means of trade. This dissertation looks at the many ways of assessing diversity in archaeology, biology, business, and economics, as …

Groundcover Management System And Nutrient Source Impact Physical Soil Quality Indicators In An Organically Managed Apple Orchard, Neal Mays

Graduate Theses and Dissertations

In March 2006, four groundcover management systems (GMS) and two nutrient sources (NS) were implemented for their ability to alter the soil physical condition of a newly established, organically managed apple (Malus x domestica Borkh.) orchard. Annual applications of municipal green compost (GC), shredded office paper (SP), wood chips (WC), and mow-blow (MB) grass mulch were utilized as GMS, and NS supplied to trees were from composted poultry litter (PL), a commercial organic fertilizer (CF), or an untreated control (NF) in a 4x3 factorial study. An established, conventionally-managed orchard was located adjacent to the organic research orchard on the same …

An Estimation Of Available Cellulosic Biomass In Ten Counties In Northeastern Arkansas From 1999-2011, Thomas Jenkins

Biological and Agricultural Engineering Undergraduate Honors Theses

The purpose of this research is to explore the possibility of siting a biorefinery that produces cellulosic ethanol in the Delta region of Arkansas, which is the main agricultural area of the state. Four major crops that the state of Arkansas produces on a yearly basis that could potentially be used for cellulosic ethanol production are: corn, rice, sorghum, and soybeans. This research will result in the generation of maps that will be useful in quantifying feedstock produced in the Delta region of Arkansas, which can be used by a biorefinery. An actual site will not be chosen based strictly …

Minimizing Wash Water Usage After Acid Hydrolysis Pretreatment Of Biomass, Noaa Frederick

Biological and Agricultural Engineering Undergraduate Honors Theses

Abstract Dilute acid pretreatment, needed to prepare biomass for saccharification, results in the production of a number of byproducts, which inhibit subsequent enzymatic hydrolysis and fermentation steps. In order to improve saccharification yields in the enzyme hydrolysis step, the pretreated biomass is often rinsed with room temperature water to remove these byproducts. High-density poplar was pretreated with 1% dilute sulfuric acid at 140 ºC for 40 minutes. After pretreatment the biomass was washed with water volumes equal to 0, 1 ½, or 3 times the biomass volume. The rinsed biomass was then enzymatically hydrolyzed and the concentrations of byproducts and …

Structural Characterization Of Engineered Muscular Mimetic, Nadia Bhatti

Biological and Agricultural Engineering Undergraduate Honors Theses

An engineered muscular mimetic (EMM) was synthesized, and its overall structure—porosity, average pore size, and pore alignment—was characterized and compared to actual decellularized skeletal muscle (DSM). The EMM’s porosity was about 20% more and average pore size was about 85% smaller compared to that of the DSM. Unlike the strong horizontal pore alignment in the DSM, no distinct orientation could be identified in the EMM structure.

Scaffolding For Human Pluripotent Stem Cell Lineage Specification, Thanh Dai

Biological and Agricultural Engineering Undergraduate Honors Theses

Current research regarding stem cells is the premise behind this project. These cells have the potential to develop into any kind of cell in the human body. Due to the scarcity of transplantable pancreas and/or pancreatic beta cells, the production of pancreatic insulin-producing cells from human embryonic stem cells (hESCs) has emerged as one of the most attractive cell therapy strategies for insulin deficient diabetes treatment. The aspect of hESC research that the project focused on was the environment or foundation the hESCs grew in. A key step to pancreatic beta cell production from hESC differentiation or growth is establishing …

The Effect Of Cell Density And Cultivation Period On Skeletal Muscle Extracellular Matrix Accumulation, Ryan Yarnall

Biological and Agricultural Engineering Undergraduate Honors Theses

Traumatic skeletal muscle injuries have led to severe disability disallowing one to perform necessary daily tasks. Different methods are under current research to rebuild muscle tissue and have it function properly. One such method is the use of extracellular matrix, or ECM, retrieved from cells to create biological scaffolds providing structure for myoblast cells to grow into tissue. This research holds promise because it utilizes the body’s own machinery, minimizing risk of a foreign body response. To obtain ECM scaffolding, one viable technique involves the cultivation of cells on polyurethane foams to collect and harvest ECM. This research investigates the …

Varying Culture Conditions To Enhance Tissue Formation, Katherine Atkins

Biological and Agricultural Engineering Undergraduate Honors Theses

For severe muscle damage, tissue engineering has become a viable option to culture muscle tissues with the ultimate goal of implantation. However, the tissues are typically cultured on permanent scaffolds which would elicit a foreign body response if placed in the body. To avoid this, biological scaffolds are ideal for tissue culture and limiting any negative reactions. A sacrificial scaffold can be used to gather extracellular matrix (ECM), which can then be used as the primary scaffold for culturing tissues for implantation. To reach the ultimate goal of implanting muscle tissue, an understanding of how to produce ECM on a …

Gesture Based Home Automation For The Physically Disabled, Alexander Hugh Nelson

Graduate Theses and Dissertations

Paralysis and motor-impairments can greatly reduce the autonomy and quality of life of a patient while presenting a major recurring cost in home-healthcare. Augmented with a non-invasive wearable sensor system and home-automation equipment, the patient can regain a level of autonomy at a fraction of the cost of home nurses. A system which utilizes sensor fusion, low-power digital components, and smartphone cellular capabilities can extend the usefulness of such a system to allow greater adaptivity for patients with various needs. This thesis develops such a system as a Bluetooth enabled glove device which communicates with a remote web server to …

A Cradle To Farm Gate Life Cycle Analysis Of Water Use In U.S. Pork Production, Eric Boles

Graduate Theses and Dissertations

The intent of this study was to analyze water use across a range of regions, scales and practices of the U.S. pork industry. A Life Cycle Assessment of water use within the pork supply chain was performed. Cumulative water use was the environmental impact category used in the LCA to evaluate the impacts of pork production processes throughout the pork supply chain. The functional unit for the analysis was the volume of water required to produce one kilogram of swine (live weight) at the farm gate.

A comprehensive literature review was used to design and propagate algorithms for the National …

Efficacy Of Probiotics For Reducing The Incidence Of Lameness In Broilers Grown On Wire Flooring, John Matthew Stark

Graduate Theses and Dissertations

Growing broilers on wire flooring provides an excellent experimental model for reproducibly triggering significant levels of lameness. In Pilot Study #1 using broilers from Line C grown on wire flooring, adding the Biomin probiotic PoultryStar® to the feed reduced the percentage of lameness by half when compared with broilers that received the control diet alone. In Pilot Study # 2 using broilers from Line B grown on wire flooring, adding the PoultryStar® probiotic reduced the percentage of lameness to 8% when compared with 28% lameness in broilers that received the control diet alone. The objective of this study was to …

Design And Fundamental Understanding Of Minimum Quantity Lubrication (Mql) Assisted Grinding Using Advanced Nanolubricants, Parash Kalita

Graduate Theses and Dissertations

Abrasive grinding is widely used across manufacturing industry for finishing parts and components requiring smooth superficial textures and precise dimensional tolerances and accuracy. Unlike any other machining operations, the complex thermo-mechanical processes during grinding produce excessive friction-induced energy consumption, heat, and intense contact seizures. Lubrication and cooling from grinding fluids is crucial in minimizing the deleterious effects of friction and heat to maximize the output part quality and process efficiency. The conventional flood grinding approach of an uneconomical application of large quantities of chemically active fluids has been found ineffective to provide sufficient lubrication and produces waste streams and pollutants …

Highly Sensitive Method For Detecting And Separating Pathogens Using Paramagnetic Particles And A Micro-Fluidic System, William Ryan

Biomedical Engineering Undergraduate Honors Theses

Water is one of the most important compounds on Earth. If a water supply is contaminated with a pathogen, it can have devastating results to an individual or a community. This research is directed at constructing an easily reproducible procedure that could increase the sensitivity of detecting and separating bacteria from the current limits of about 100 cells to 10-20 cells per sample with a ultimate goal of a single cell detection. Here, we report a micro-fluidic system to magnetically capture pathogenic bacteria in water followed by rapid impedance detection using Escherichia coli K-12 as a model bacterium. Paramagnetic beads …

Comparing Decellularized Muscle Tissue With An Engineered Muscle Biomaterial, Katelin Cherry

Biomedical Engineering Undergraduate Honors Theses

Decellularized tissues composed of extracellular matrix are commonly used for tissue transplantations but this method has many limitations. An alternative approach is to create an extracellular matrix by seeding degradable foams with cells, culturing these foams to allow extracellular matrix to be secreted from the cells, then washing away the degradable foam to collect the material that is produced. This study was interested in comparing decellularized skeletal muscle tissue to an engineered biomaterial that was seeded with skeletal muscle myoblast cells. Collagen content of decellularized tissue and engineered biomaterial were quantified using a hydroxyproline assay to compare the two samples. …

Ecology And Flock-Following Behavior Of The Wedge-Billed Woodcreeper In Eastern Ecuador, Abigail Darrah

Graduate Theses and Dissertations

The wedge-billed woodcreeper (Glyphorynchus spirurus) is a common understory suboscine passerine of lowland Neotropical rainforests. It frequently joins mixed-species understory flocks but also regularly forages alone, and thus is an excellent model species on which to conduct comparative behavioral observations to examine the hypothesized costs and benefits of flock-following. Individuals exhibit variable flocking propensities (proportion of time spent with flocks), and thus observing the correlations between flocking propensity and physical and environmental factors can provide further insight into the importance of flock-following to the ecology of this species. Despite its abundance at many sites and its wide geographic range, surprisingly …

Arkansas Physics Times, April 2013, Society Of Physics Students (American Institute Of Physics)

Arkansas Physics Times

No abstract provided.

Mole Street Journal, March 2013, University Of Arkansas, Fayetteville. Dept. Of Chemistry And Biochemistry

Mole Street Journal

No abstract provided.