Life Sciences Commons^™

Persistence Of Enteric Viruses On Surfaces Under Varying Environmental Conditions, Nicole L. Turnage

Graduate Theses and Dissertations

Human enteric viruses such as human norovirus (hNoV) and Aichivirus A (AiV) are common foodborne viruses with hNoVs being identified as the leading causative agent of foodborne illnesses in the U.S. Moreover, hNoVs have been identified as the leading cause of nonbacterial acute gastroenteritis in the U.S. and worldwide. Fomite surface contamination is a major transmission route for enteric viruses. The application of an optimized virus recovery method from fomites is essential for better understanding of virus persistence under varying environmental conditions (EC). This study aimed to optimize a surface sampling method for virus recovery from nonporous food contact surfaces …

Characterization Of A Tuberous Sclerosis Complex 2 Variant And Its Interaction Involving The Ras-Related Protein Rheb, Nosaiba Shokr

Graduate Theses and Dissertations

Structure-function relationships of any complex underlie the molecular details of the biological interactions. Rheb, Ras Homology Enriched in Brain, is a Ras-related protein, and it is genetically identified as a molecular switch. Rheb is regulated by cycling between the biologically active GTP and inactive GDP-bound forms. This regulation is partially controlled by an interaction with Tuberous Sclerosis Complex2 (TSC2), a GTPase activating protein (GAP). Upon interaction, TSC2 stimulates Rheb GTP hydrolysis and diminishes the mammalian target of rapamycin (mTOR) pathway. The mTOR pathway is involved in proteins synthesis, cell cycle, and signaling. Mutation in TSC2 causes abnormal activation of Rheb …

The Cost Of Forward Contracting In Mississippi River Barge Freight And Cif Nola Markets, Bradley John Isbell

Graduate Theses and Dissertations

Grain elevators often use paper markets to mitigate the risk of (or hedge) their cash grain positions, as well as establish a profit margin through basis trading. Typically, merchandisers use futures or forward contracts to perform these transactions. However, in order to liquidate a cash grain position, grain transportation must be arranged in order to deliver the grain to the buyer. For elevators located along the Mississippi River system selling to Gulf export elevators in New Orleans, that mode of grain transportation is most likely river barge. Contracts for barges are bought and sold by grain merchants either directly with …

The Structural And Functional Properties Of A Double Mutant Of Human Acidic Fibroblast Growth Factor (Hfgf-1), Arwa Mohammed Alghanmi

Graduate Theses and Dissertations

Human acidic Fibroblast Growth Factor 1 (FGF-1), a member of the FGF superfamily, is a potent mitogen and heparin-binding protein involved in a broad spectrum of biological processes, including angiogenesis, cell proliferation, and wound healing. Design of hFGF-1 with an increased thermal stability and an enhanced cell proliferation activity is highly desired for wound healing applications. Herein, we have designed the variant of FGF-1 by substituting two important amino residues in the heparin-binding pocket. The variant was overexpressed in Escherichia coli and was successfully purified to homogeneity using an affinity chromatographic procedure. Far-UV circular dichroism spectroscopic analysis showed that the …

Evaluating The Impact Of An All-Vegetable Protein Supplement Containing Fat Emulsifiers And Probiotics On Broiler Performance, Jordan Weil

Graduate Theses and Dissertations

Currently, several niche markets, such as organic and “all natural”, are marketed within the poultry industry. However, little research has been undertaken to determine the cost-effectiveness of poultry diets used to produce chicken within these markets. Specifically, the economics and resulting profits associated with raising chicken with antibiotic-free, all-vegetable (AV) diets are not evaluated. As national chain restaurants such as Chick-fil-A and Panera Bread begin to mandate poultry suppliers raise chicken without antibiotics and use AV diets, it becomes increasingly important to evaluate the economics for integrators. Given the rapidly changing feeding strategies necessary to respond to consumers’ and wholesalers’ …

Evaluating Methods For Quantifying Evapotranspiration In Arkansas Rice, Colby Reavis

Graduate Theses and Dissertations

The goal of this study was to evaluate different methods for quantifying evapotranspiration (ET) in commercial rice fields using different irrigation regimes. The rice fields were located in south central Arkansas. The different irrigation regimes were alternate wetting and drying (AWD) and continuous flooding (CF). Alternate wetting and drying and conventional flooding estimates of ET were 602 mm and 570 mm, respectively, based on field observations using eddy covariance. Models used to estimate ET estimated values between 498 and 653 mm for the 2015 growing season. The Penman Monteith actual evapotranspiration model (PM AET) performed best when compared to the …

Phylogenetic Diversity Of The Bacterial Communities In Craft Beer, Lindsey Rodhouse

Graduate Theses and Dissertations

The craft beer industry is increasing in popularity in the United States. The craft brewing process typically does not use a pasteurization step, therefore the boiling process is the primary critical control step. Any microorganisms introduced after boiling, or those that are not killed during boiling, are likely to participate in fermentation and persist in the final product. Previous culture-based studies have isolated bacteria and yeast from craft beers at specific time points, but little research has been done on the process as a whole. The objectives of this research are to (1) track bacteria development throughout the brewing process …

Membrane Surface Engineering For Biochemical Applications, Anh T. Vu

Graduate Theses and Dissertations

Synthetic membranes have been frequently used for many fields, such as, the food and beverage, biopharmaceutical, and biofuel industries. In the beer industry, microfiltration frequently suffers from fouling due to the interaction between different species. It is shown that polyphenols can form cross-links with protein molecules, forming insoluble aggregates. However, by adding an optimal amount of polysaccharides these aggregates can be disrupted thus reducing fouling by the aggregates. Confocal laser scanning microscopy (CLSM) is a powerful technique to locate the foulants inside the wet membrane in order to understand more about the behavior of fouling in microfiltration.

Membrane surface modification …

The Effects Of Calorie Information Disclosures On Food Choice And Retailer-Related Outcomes, Christopher Berry

Graduate Theses and Dissertations

Federal legislation will begin requiring the provision of calorie information on the menus and menu boards of restaurants and other retail food establishments with 20 or more locations in May 2018. Food retailers not included in this mandate can choose to voluntarily provide calorie information to consumers. However, there are concerns that this major policy change will not have the desired widespread positive effects on consumer choice behavior. Further, although proponents of calorie labeling argue that consumers have the right to know the calorie content of their food orders, many food retailers have argued that calorie labeling is too expensive …

Removal Of Endocrine Disrupting Compounds Using Membrane Bioreactor, Mohanad Ali Abdulsahib Kamaz

Graduate Theses and Dissertations

The presence of endocrine disrupting compounds (EDCs) and pharmaceutically active compounds (PhAC) such as pesticides, personal care products, antibiotics and pharmaceutical compounds, in sewage, industrial, and domestic waters has extensively become the major concern for health and environmental organizations. These compounds have the ability to interact with mammalian endocrine system and disrupting their functions. The traditional activated sludge processes are designed to degrade solids, organic carbon and nitrogen loading. Although several treatment steps in a wastewater treatment plant can contribute to partial removal of EDCs, effective removal has been a challenge due to their resistant chemical and biological degradation and …

The Effect Of Blinded Hydration State On Thermoregulation And Performance In Male Cyclists, Jon David Adams

Graduate Theses and Dissertations

Purpose: The purpose of these studies was to observe the effect of dehydration on exercise performance while subjects were blinded to their hydration status. Methods: Study 1: Seven male cyclists (weight: 71±8 kg, body fat: 14±6%, VO2peak: 59.4±6 ml∙kg-1·min-1) exercised for 2 hours on a cycle ergometer at 55% VO2peak, in a hot-dry environment (35°C, 30% rh), with a nasogastric (NG) tube under euhydrated (EUH-NT) and hypohydrated (DEH-NT) conditions. In both trials, thirst was matched by drinking 25 mL every 5 min. In the EUH-NT trial sweat losses were fully replaced via the NG tube. Following the 2 hours of …

Evaluating Thermal Comfort Of Broiler Chickens During Transportation Using Heat Index And Simulated Electronic Chickens, Kaushik Luthra

Graduate Theses and Dissertations

Broilers experience high physiological stress during pre-slaughter transport, especially under extremes of thermal environment. Characterization of thermal environment on the trailer is crucial to identify stress-prone regions during transportation. At the same time, Broilers experience high physiological stress during pre-slaughter transport, especially under extremes of thermal environment. Characterization of thermal environment on the trailer is crucial to identify stress-prone regions during transportation. At the same time, quantification of heat loss of the broilers loaded on trailers is important in understanding the well-being of the broilers. We have developed four electronic chickens (E-chickens) to simulate the sensible heat loss of live …

Application Of X-Ray Imaging As A Technique For Fissure Detection In Rough Rice Kernels, Zephania R. Odek

Graduate Theses and Dissertations

Fissured rice kernels break during milling, leading to head rice yield (HRY) reductions. Conventional fissure detection instruments cannot be used to observe fissures in rough rice kernels, the form in which rice in normally dried and stored. X-rays can penetrate hulls allowing visualization of the internal structure of a rough rice kernel. This study evaluated the capability of X-ray imaging to adequately detect fissures in rough rice and established a correlation between HRY and the fissured kernel percentage (FKP) in a rough rice sample. Fifteen long-grain rice cultivars, harvested in Arkansas in 2015 and 2016 were dried using heated air …

Rna Sequencing In The Development Of Cancer-Cachexia, Thomas Allen Blackwell

Graduate Theses and Dissertations

Introduction: Cancer is a major public health problem in the U.S. and the world. In 2013 there were an estimated 1,660,290 new cases of cancer in the U.S. Cancer-Cachexia (CC) is a common effect of many cancers, and is directly responsible for 20-40% of cancer-related deaths. The mechanisms that control the development of CC are not well understood. Most investigations of CC focus on the post-cachectic state and do not examine the progression of the condition. The purpose of this study was to utilize RNA sequencing to analyze transcriptomic alterations throughout the progression of CC. Methods: Lewis Lung Carcinoma cells …

Characterization Of The Relationships Between Soybean Yield, Trifoliolate Leaf Chloride Concentration, And Cultivar Chloride Inclusion/Exclusion Rating, Dillon Cox

Graduate Theses and Dissertations

Chloride toxicity is recognized as yield limiting problem in soybean [Glycine max (L.) Merr.] production. Limited information is available to accurately diagnose and manage Cl toxicity. The only recommendation for Cl toxicity management is to plant an excluder cultivar, however the cultivar Cl sensitivity rating system (excluder, includer, and mixed) does not appear to capture the variability in cultivar Cl tolerance. The objectives of this research were to i) develop critical tissue-Cl concentrations in which yield loss occurs for excluder and includer cultivars and ii) investigate the variability in cultivar Cl ratings. A study was conducted across five site-years using …

Effects Of Chemical And Enzymatic Modifications On Starch And Naringenin Complexation, Ana Isabel Gonzalez Conde

Graduate Theses and Dissertations

Naringenin is a flavanone naturally present in grapefruit and tomato skin, which has been demonstrated to have health benefits. However, because of the low water solubility and bioavailability, naringenin applications are limited. Starch inclusion complexes have been shown to improve the solubility and bioavailability of poorly water soluble bioactive compounds. The present study aimed to prepare and characterize complexes of naringenin with starches, including potato starch and high amylose corn starch (Hylon VII), which were chemically (acetylation or hydroxypropylation) and enzymatically modified (debranched or debrahced/β-amylase treated). Soluble and insoluble complexes were recovered, and their physicochemical properties were characterized. The treatments …

Experiment-Based Quantitative Modeling For The Antibacterial Activity Of Silver Nanoparticles, Mohammad Aminul Haque

Graduate Theses and Dissertations

Silver (Ag) has been well known for its antimicrobial activity for a long time. Recent research showed the potential of Ag nanoparticles as emerging antimicrobial agents. However, little quantitative analysis has been performed so far to decipher the mechanism of interaction between nanoparticles and bacteria. Here, a detailed analysis based on kinetic growth assay and colony forming unit assay has been carried out to study the antimicrobial effect of Ag nanoparticles against Escherichia coli (E. coli) bacteria. It was observed that the presence of Ag nanoparticles increased the lag time of bacterial growth while not affecting the maximum growth rate …

Interactive Effects Of Flow Regime, Climate Change, And Angler Harvest On Smallmouth Bass At The Southern Range Extent, Christopher Middaugh

Graduate Theses and Dissertations

The Ozark-Ouachita Interior Highlands of Arkansas, Oklahoma, and Missouri are the southern extent of native Smallmouth Bass Micropterus dolomieu range. Smallmouth Bass are an important species economically and ecologically, but it is unknown how climate change may affect them in this region and in particular how Smallmouth Bass may be affected differently across streams from various flow regimes. Here I present three projects investigating how climate change, flow regime, and angler harvest may interact to affect Smallmouth Bass over the coming century. I first modeled present and future water temperatures and calculated growth rate potential for Smallmouth Bass from streams …

Effects Of Northern Bobwhite Management On Raccoon Abundance, Habitat Selection, And Home Range In Southwest Missouri, Jacob Cody Mcclain

Graduate Theses and Dissertations

Habitat management has become vital for northern bobwhite (Colinus virginianus) conservation. In Missouri, efforts to conserve remaining populations on public lands have included the use of two management models. The Intensive Management Model (IMM) promotes hard edges, by creating a juxtaposition of different habitat types, while the Extensive Management Model (EMM) maintains a grassland-dominated landscape through the processes of fire and grazing. Preliminary results suggest that bobwhite success is significantly higher on EMM sites than IMM sites. Management efforts through IMM may be hindered by unintentionally managing for nest predators like raccoons (Procyon lotor). Nest predators may forage more often …

Spatial Variability Of Seedling Disease Pressure In Cotton Fields, Kyle Douglas Wilson

Graduate Theses and Dissertations

Seedling diseases are important factors in cotton stand establishment, and seedling disease pathogens are widespread in fields in Arkansas. Little is known about the variability of seedling disease pressure within fields. With expanded adoption of site-specific management and other precision agriculture approaches, cotton producers are increasingly interested in predicting seedling disease pressure, particularly in spatially variable fields. The cotton seedling disease pathogens include the soilborne pathogens Thielaviopsis basicola, Rhizoctonia solani, Pythium spp., and Fusarium spp. These pathogens can survive in soil for long periods and, and when the environment is conducive, these pathogens can act individually or in combination to …

Environmental And Climatic Constraints On Large-Scale Camelina Production In Eastern Arkansas, Benjamin Robert Tracy

Graduate Theses and Dissertations

Camelina sativa is a cold weather crop that is typically grown in semi-arid environments in the Western United States, usually as a spring crop, but sometimes during the winter. Research analyzing climate data and soil hydrology is important to better understand the environmental and terrain conditions necessary for Camelina farming wherever it is proposed for large-scale production. This study focused on various conditions and constraints pertaining to the potential for Camelina as a crop biofuel in Eastern Arkansas. Due to interest in the economic potential of crop biofuels in this area, and in particular the low input costs for Camelina, …

Identification Of Molecular Signatures Of Environmental And Nutritional Stress Responses In Poultry, Phuong Hieu Nguyen

Graduate Theses and Dissertations

Poultry production plays an important role in the food supply and security for billions of people. Poultry meat is considered the most efficient, nutritious source of protein, without religious taboos, and is relatively inexpensive. However, the poultry industry is facing substantial challenges. The global environmental temperature has experienced dramatic changes in the last few years. Modern broilers are not well adapted to environmental challenges (heat and cold stress), which have resulted in heavy economic loss in the poultry industry worldwide. In addition, the use of feed restriction regimens in management of breeders as well as the transportation of young chicks …

Influence Of Stream Permanence, Predation, And Invasive Species On Crayfish In The Ozark Highlands With An Emphasis On Species Of Greatest Conservation Need (Orconectes Marchandi, Orconectes Eupunctus And Cambarus Hubbsi), Allyson Noelle Yarra

Graduate Theses and Dissertations

Due to the ecological importance of crayfish and the increasing vulnerability of freshwater systems due to habitat loss, invasive species, and hydrologic alteration, understanding crayfish-environment relationships is crucial in the context of aquatic species conservation. I sought to examine the influence of hydrologic variation among intermittent and permanent streams on crayfish occupancy, abundance, predation risk, and potential vulnerability to invasive species effects. I conducted crayfish and environmental data sampling during two consecutive summers across 20 Ozark streams of differing permanence levels (10 intermittent, 10 permanent). In these same streams, I conducted fish and scat surveys over the course of four …

Influence Of Histidine Residues, Ph And Charge Interactions On Membrane-Spanning Peptides, Ashley N. Henderson

Graduate Theses and Dissertations

Designed transmembrane peptides were employed for investigations of histidine residues within the hydrophobic environment of the lipid bilayer by means of oriented solid-state deuterium NMR spectroscopy. Using the model peptide GWALP23 sequence (GGALW(LA)6LWLAGA) as a host framework, the effects of single and double histidine mutations were explored. Replacement of leucine residue 12 to polar neutral histidine had little influence on the peptide average orientation, however under strongly acidic pH conditions in DOPC bilayers, the histidine becomes positively charged (pKa 2.5) and the GWALP23-H12 peptide exits the membrane and adopts a surface-bound orientation. Conversely, mutation of leucine 14 to neutral histidine …

Temporal Evaluation Of Corn Respiration Rates Using Pressure Sensors, Gagandeep Singh Ubhi

Graduate Theses and Dissertations

High respiration rate of a grain indicates faster degradation of its dry matter. Proper grain management requires chronological and precise measurements of carbon dioxide evolved from grain respiration during the postharvest storage duration. Therefore the main goal of this research was to develop a new technique that evaluates temporal corn respiration rate using pressure sensors. It was based on measuring pressure drop associated with the grain respiration in a closed container and using it to calculate the grain respiration rates.

Dry corn (Zea Mays L.) was procured from a local farmer and stored at 4ºC. Corn rewetting technique was applied …

Comparing Before-And After-School Neurocognitive Performance In High School Athletes- Implications For Concussion Management, Morgan Anderson

Graduate Theses and Dissertations

There are several factors that influence computerized neurocognitive testing performance however, one factor that has not been examined is the potential deleterious effects of cognitive fatigue from an academic school day combined with time of computerized neurocognitive testing (CNT) administration. The primary purpose of this study was to compare before-and after-school CNT performance and total symptoms in non-concussed high school student athletes. The secondary purpose of this study was to compare before-school and after-school CNT performance and total symptoms and chronotypes in non-concussed student athletes. A crossover design was used to compare before-and after-school CNT performance and total symptoms of …

Phenology, Habitat Use, And The Impacts Of Wetland Management On Autumn Migrating Rails In Missouri, Auriel M.V. Fournier

Graduate Theses and Dissertations

Rails (Family: Rallidae) are among the least studied birds in North America, in large part due to their elusive nature. As a wetland-dependent species, understanding the timing of their migration and their habitat needs during migration is especially important since management needs to be timed to balance the needs of many species. I developed and verified a new distance sampling based nocturnal ATV spotlight survey because traditional call-broadcast surveys are not effective during autumn migration because of the drop off in call rate after the breeding season. These surveys allow us to ask point-level questions about what habitats rails select …

Refusing To Be Dispossessed: African American Land Retention In The Us South From Reconstruction To World War Ii, Camille Goldmon

Graduate Theses and Dissertations

African Americans in the South were tied to the land during slavery and after emancipation. Many felt that land ownership was the key to freedom. For decades, black farmers strove for land ownership, in many cases falling prey to sharecropping and tenancy agreements in the meantime. Despite this drive toward independent farming, however, since 1920, there has been a steady decline in the number of black farm owners. This trend is especially prevalent in the Southern United States. The black farm owners who persevered through periods of economic, social, and political turmoil were able to, for varying reasons, navigate those …

Development Of A One Pass Microwave Heating Technology For Rice Drying And Decontamination, Deandrae Lynette Smith

Graduate Theses and Dissertations

An industrial microwave (MW) system operating at 915 MHz frequency was used to dry high moisture content (MC) (23% to 24% wet basis) medium-grain rough rice samples (cv. Jupiter). The rice beds were contained in a modified tray that accommodated up to 9 kg of rice separated by thin fiberglass mesh in 3 kg increments. Each layer of rice was fitted with fiber optic sensors connected to a real time data logger during MW treatments. It was determined that drying rice to a MC of 14% to 16% was feasible with the application of MW specific energy at 600 kJ/kg-grain …

Evaluation Of Safening Effects To Herbicides Conferred Via Insecticide Seed Treatments In Soybean (Glycine Max) And Grain Sorghum (Sorghum Bicolor), Nicholas Robert Steppig

Graduate Theses and Dissertations

Interactions between herbicides and insecticides in crop production have been documented for a number of years. Research has shown that applications of some organophosphate insecticides at planting can reduce cotton injury following applications of the soil-applied herbicide clomazone. Additionally, recent research has shown that, when applied as seed treatments prior to planting, some neonicotinoid insecticides can safen rice to drift from both glyphosate and imazethapyr. Since insecticide seed treatments are commonly used in many crop production systems throughout the Midsouth, exploring their ability to reduce injury from herbicides in other crops besides rice is of great interest. Presently no research …