Digital Commons Network^™

Novel Self-Assembly Of Fullerene-Based Dyads, Ashley D. Anderson

Theses and Dissertations

Eventual depletion and environmental toxicity of natural non-renewable energy resources are two issues pushing research toward alternative energy resources. Nature’s process of renewable, unlimited, clean energy production is photosynthesis and porphyrins are a critical component due to their ability to undergo photoinduced electron transfer. This property also makes porphyrins excellent candidates for applications such as solar cells, water splitting, and optical sensing. Researchers have previously tethered porphyrins to fullerene (C60), an excellent electron acceptor, to mimic the reaction centers in photosynthesis. Photoinduced electron transfer in these donor-acceptor dyads has been investigated with particular focus on factors such as the donor, …

Comparison Of Play Frequency In Four Sympatric Monkey Species In Kibale National Park, Uganda, Sara G. Lucci

Theses and Dissertations

This study describes play in red colobus (Procolobus rufomitratus), grey-cheeked mangabeys (Lophocebus albigena), black-and-white colobus (Colobus guereza), and redtail monkeys (Cercopithecus ascanius) to test Instinct-Practice Theory. Solitary locomotor play was different among the species. Rough-and-tumble play was different between male and female redtail monkeys. These results partially support Instinct-Practice Theory.

Adult And Juvenile Rats Differentially Express Mpfc Glua2 Following Traumatic Memory Retrieval, Edgar Rodriguez

Theses and Dissertations

To advance our understanding of how traumatic memories are modulated between adults and juveniles, we characterize the AMPAr subunits, GluA1, GluA2, GluA3 in the mPFC of rodents following traumatic memory retrieval.

GluA2 was differentially expressed in adults but not juveniles rats. There were no changes in GluA1 or GluA3 expression

Judging Facial Expressions Of Emotion: Effects Of Gender, Raine Palladino

Theses and Dissertations

This study examined how quickly people recognize happy, neutral or angry emotional expressions on faces that varied in gender presentation and femininity/masculinity of facial features. Facial features influenced judgments of emotion more for women than men. Neutral expressions were more likely seen as angry on a woman’s face.

The Effect Of Dopamine Blockade On Sensorimotor Gating In Social Phenotypes Of The African Cichlid Fish Astatotilapia Burtoni, Raymond A. Turco

Theses and Dissertations

We asked if blocking dopamine could improve implicit sensory gating deficits in a socially-defeated fish of a naturally-agonistic species. This study investigated the effects of dopamine D2R receptor antagonist metoclopramide on sensorimotor gating using a prepulse inhibition (PPI) paradigm in social phenotypes of male A. burtoni African cichlid fish.

Weak Social Support As An Indicator For Worse Trauma Related Symptoms, Michael B. Sugarman

Theses and Dissertations

This study investigated the relationship between social support and trauma related symptoms in trauma exposed participants. Using the SCID and CAPS, weak family support factors were found to be associated with a greater number and severity of trauma related symptoms; suggesting that family support is important for trauma exposed people.

Behavioral Hypervigilance In A Normative Population, Karly Weinreb

Theses and Dissertations

Hypervigilance is conceptualized as a symptom of trauma-related disorders, however it can also occur in a normative population. To distinguish normative hypervigilance from trauma-related hypervigilance, 372 participants (123 trauma-exposed and 249 non-trauma-exposed) completed a questionnaire assessing hypervigilance in contexts. Trauma-exposed participants reported greater levels of hypervigilance in 3 contexts.

Biofilm Formation And Physiological Heterogeneity Of Listeria Monocytogenes, Yue-Jia Lee

Theses and Dissertations

A contributing factor in recurrent Listeria monocytogenes (L. monocytogenes) food contamination is that this bacterium produces biofilms on surfaces to persist in food-processing environments. Quorum sensing (QS) is a cell-to-cell communication system utilized by bacteria within biofilms to collaborate and adapt to environmental stresses. However, the details of how the QS-dependent network contributes to biofilm development of L. monocytogenes have yet to be well understood. By comparing the transfer rates of planktonic and biofilm (sessile) L. monocytogenes from stainless steel blades to bologna slices, we found that sessile bacteria had reduced transferability onto a single slice but caused the increase …

Black Flies (Diptera: Simuliidae) Occurring In Mississippi, And Their Medical, Veterinary, And Economic Impacts, Tina M. Nations

Theses and Dissertations

Little is known about black fly pest species in Mississippi, other than research from the 1930s. A better understanding of the pest species that occur in Mississippi is important for human and animal health. My research focused on what species of black flies occur in Mississippi, their seasonality and distribution, and a detailed systematic survey of the primary pest species. Lastly, I attempted to quantify nuisance effects and economic impacts of black flies on people, backyard poultry, and livestock. I examined scientific literature and records of black flies occurring in the southeastern U.S., and particularly Mississippi. This search revealed several …

Characterization Of Dissolved Organic Matter And Determination Of Its Biogeochemical Significance In Coastal And Inland Water Bodies, Sankar Manalilkada Sasidharan

Theses and Dissertations

Dissolved organic matter (DOM) is a major component of natural waters and provides essential nutrients for aquatic organisms. However, excess DOM in the water results in water quality issues and affects the aquatic life negatively. The present research evaluated the source, composition, reactivity, dynamics, and the spatial distribution of DOM in diverse water bodies using spectrofluorometric methods in tandem with multivariate statistics. The study was conducted in the inland and coastal water bodies of Mississippi, Louisiana, and Alabama over a period of three years (2016 to 2018). Surface water samples were collected from spatially separated waterbodies with diverse land use …

Characterization Of Xylaria Sp., The Causal Agent Of Taproot Decline In Mississippi Soybean, Hope Becton

Theses and Dissertations

Taproot decline (TRD), caused by an undescribed species of Xylaria, is an emerging root disease of soybean in Mississippi. Xylaria sp. isolates were collected from soybean roots and used to characterize TRD distribution as well as optimal growth temperature, pathogenicity, alternative host range, in vitro pathogenicity, and fungicide sensitivity. The 24 selected Xylaria sp. isolates from the 2016 collection had a mean optimal growth temperature of 26.7°C, and were pathogenic to soybean; however, differences in virulence occurred among isolates. Five selected Xylaria sp. isolates produced stroma on six hosts: corn, cotton, peanut, rice, sorghum, and wheat. Xylaria sp. colonized corn, …

A Coupled Finite Element-Mathematical Surrogate Modeling Approach To Assess Occupant Head And Neck Injury Risk Due To Vehicular Impacts, Parker Berthelson

Theses and Dissertations

This study presents mathematical surrogate models, derived from finite element kinematic response data, to predict car crash-induced occupant head and neck injury risk for a broad range of impact velocities (10 – 45 mph), impact locations, and angles of impact (-45° to 45°). The development of these models allowed for wide-scale injury prediction while significantly reducing the overall required number of impact test cases. From these, increases in both the impact velocity and the impact’s locational proximity to the occupant were determined to result in the greatest head and neck injury risks. Additionally, strong interactions between the impact orientation variables …

A Machine Learning Approach To Genome Assessment, Charles Adam Thrash

Theses and Dissertations

A key use of high throughput sequencing technology is the sequencing and assembly of full genome sequences. These genome assemblies are commonly assessed using statistics relating to contiguity of the assembly. Measures of contiguity are not strongly correlated with information about the biological completion or correctness of the assembly, and a commonly reported metric, N50, can be misleading. Over the past ten years, multiple research groups have rejected the overuse of N50 and sought to develop more informative metrics. This research seeks to create a ranking method that includes biologically relevant information about the genome, such as completeness and correctness …

A Multiscale Modeling Approach To Investigate Traumatic Brain Injury, Amirhamed Bakhtiarydavijani

Theses and Dissertations

In the current study, mechanoporation-related neuronal injury as a result of mechanical loading has been studied using a multiscale approach. Injurious mechanical loads to the head induce strains in the brain tissue at the macroscale. As each length scale has its own unique morphology and heterogeneities, the strains have been scaled down from the macroscale brain tissue to the nanoscale neuronal components that result in mechanoporation of the neuronal membrane, while relevant neuronal membrane mechanoporation-related damage criteria have been scaled up to the macroscale. To achieve this, first, damage evolution equations has been developed and calibrated to molecular dynamics simulations …

Agronomic Management Of Flooded Soybean In Mississippi Delta, William Lassiter

Theses and Dissertations

Flooding is a major obstacle for soybean production in the Mississippi Delta. One management practice that soybean producers use to mitigate the effects of flooding is planting soybean on raised beds. Another potential management practice that could be employed in the Mississippi Delta is the use of flood tolerant soybean cultivars. Therefore, the objective of this study was to evaluate the effectiveness of raised beds for flooding management and compare the tolerance of six soybean cultivars under flooded conditions at multiple growth stages and flood durations. Field studies were established during the 2017 and 2018 growing seasons at the Mississippi …

Alternative Therapeutic Mechanisms Of Novel Phenoxyalkyl Pyridinium Oximes To Treat Organophosphorus Compounds, Royce Harrison Nichols

Theses and Dissertations

Organophosphates (OPs), such as nerve agents and insecticides, potently inhibit acetylcholinesterase (AChE). Oximes, such as the currently FDA approved oxime 2-PAM, remove the OP from the inhibited enzyme. 2-PAM is effective against select OPs and cannot effectively pass the blood-brain barrier to attenuate OP induced CNS damage. Our laboratory has synthesized a series of substituted phenoxyalkyl pyridinium oximes (Patent number: 9,227,937) that have demonstrated increased survival rates compared to 2-PAM. This research investigated 1) in vitro oxime reactivation of rat, human, and guinea pig serum BChE after inhibition by nerve agent and insecticidal OPs; 2) in vitro determination of reactivation …

Characterization Of The Fungicidal Activity And Biochemical Impact Of Occidiofungin, A Novel Antifungal Compound Derived From Burkholderia Contaminans, Dayna Emrick

Theses and Dissertations

Fungal infections have a significant impact on the world population, with estimates of over 1.6 million deaths a year. One contributing factor is the increasing number of fungi resistant to the current clinical treatments, including the last approved family of antifungal compounds introduced into the market over a decade ago. This is driving the search for new antifungals with different biological targets. A new potential antifungal occidiofungin, is a cyclic glycolipopeptide isolated from the soil bacterium Burkholderia contaminans MS14 with a broad spectrum of activity against both human and plant pathogens. Kill kinetics demonstrated that this compound is fungicidal and …

The Effect Of Short And Long-Term Nsaid Administration On Osteotomy Healing In Dogs, Hayley Gallaher

Theses and Dissertations

The ability of NSAIDs to delay bone healing has been long known, although the extent and exact mechanism remains elusive. The present study evaluates the effect of short duration NSAID on bone healing in dogs following experimental tibial osteotomy. Carprofen was administered twice daily for either 0, 2, or 8 weeks following surgery. Bone healing was evaluated radiographically using RUST scoring at 4 and 8 weeks postop. Postmortem, quantitative CT of for bone mineral density analysis, histologic cartilage:callus ratio of the fracture, and biomechanical testing were performed. Biomechanically, stiffness and maximum stress were higher in dogs that received no carprofen …

The Silent Epidemic: Disparities And Obstacles In Obtaining Oral Care, Heather Hicks

Theses and Dissertations

American’s agree that dental health is important and vital to our overall wellbeing. However, not every American is achieving the same degree of oral health. Obstacles that American’s face include dental health disparities, limited access to affordable dental care, and limited access to dental insurance. This study examined how disease risk is shaped within the culture of oral health in Florida. This study examined those who provide dental care, those who cannot afford dental health insurance but earn too much money to qualify for Medicaid, and those with dental insurance. Hypotheses two and three were proven to be true, while …

Purification And Characterization Of Copr, A Copper(Ii) Dependent Transcription Factor, Prakash Khanal

Theses and Dissertations

Transcription factors (TFs) are proteins that respond to a specific chemical signal and bind to DNA. In some bacteria, TFs control transition metal ion homeostasis by specifically binding with a particular metal ion or ions and then interacting with DNA. Although most first row metal ions are required as micronutrients for life, many of them can cause cellular damage or death if their concentrations are too high; this makes these TFs and their biological interactions excellent targets for drug development. The bacteria, Streptococcus pneumoniae is a pathogenic microorganism responsible for a range of diseases that target the young and the …

Purification And Preliminary Characterization Of Zinc(Ii) Dependent Transcription Factor Adcr, Asm Saem

Theses and Dissertations

Transition metals are essential micronutrients for organisms. Excess zinc can be lethal to bacterial survival. Zinc homeostasis is crucial and is regulated by zinc uptake and efflux system. Streptococcus pneumoniae AdcR (Adhesin competence regulator) transcription factor is the member of MarR (multiple antibiotic resistance regulator) family proteins that suppress the zinc upregulation transporter. In the absence of zinc, AdcR has less affinity to bind DNA and uptake genes are expressed in order to transport zinc inside the cell. Streptococcus pneumoniae is a gram-positive human pathogen that is capable of colonizing in the human nasopharynx, especially in young children and leads …

Remote Sensing Of Colored Dissolved Organic Matter Using Unmanned Aerial Systems And Assessment Of The Influence Of Dissolved Organic Matter On The Oyster Reefs In The Western Mississippi Sound, Sudeera Wickramarathna Galapita Pallayapelage

Theses and Dissertations

Oyster reefs in the western Mississippi Sound (WMS) are dependent on the salinity moderation by freshwater input. However, freshwater brings in high amount of pollutants, which affect the oysters negatively. Oyster diebacks happened as a result of hypoxia caused by excessive organic matter input to WMS in summer 2017. Colored dissolved organic matter (CDOM) is widely used as a proxy for determining organic matter distribution. In this study, hyperspectral and multispectral remote sensing data collected using unmanned aerial systems and in situ CDOM data were used to develop algorithms in order to retrieve CDOM remotely. Collected physical and biogeochemical parameters …

Ruthenium(Ii) Arene Complexes For Asymmetric Catalysis, Zhenyu Zhu

Theses and Dissertations

Within the last few years, a significant contribution to the discovery of sp2C−H activation processes and useful applications for cross-coupling C−C bond formation has been achieved by the use of ruthenium(II) arene catalysts. The aim of this thesis is to describe a modular approach for the synthesis of several ruthenium(II) arene complexes with the potential for C−H activation. Another cutting-edge field, catalytic enantioselective functionalization of C−H bonds by transitional metal catalysts, has also been realized within the last few years. It represents a highly atom- and step-economic approach toward the generation of structural complexity. However, the majority of current methodologies …

Secondary Agricultural Teacher Self-Efficacy In Agribusiness And The Relationship To Collegiate Course Work, William Michael Vestal

Theses and Dissertations

A study was conducted to determine the relationship between agribusiness self-efficacy and business related collegiate courses. One hundred eleven (N = 111) Mississippi and Tennessee secondary agricultural education teachers completed a researcher developed survey that measured agribusiness self-efficacy using 88 competencies from Mississippi and Tennessee secondary agribusiness courses. Participants rated their confidence to teach each competency using a 5 point scale with 1 as no confidence and 5 as very confident. The survey also assessed the types and number of collegiate-level business related courses completed by the participants as well as other demographic factors. Multiple linear regression, ANOVA, and Spearman's …

Novel Methods For Detecting Glycan Receptors For Influenza A Virus And Exploration Of The Function Of The Sialyltransferases On Influenza Viral Infection, Kaijun Jiang

Theses and Dissertations

Sialic acids (Sias) are receptors for influenza A viruses (IAVs). The influence of individual sialyltransferases on the Sias expressed is not understood. Also, sensitive methods to distinguish Sias on the cells are lacking. Our goals were to establish a method to detect Sias on the cell and to evaluate the importance of CMP-sialic acid transporter (SLC35A1) and ST6 beta-galactoside alpha-2,6-sialyltransferase 1 (ST6GAL1) for IAV infection. Aproximity ligation assay was established to detect and quantify Sias.

Development Of Recombinant Staphylococcal Cytotoxins And Superantigens As Vaccine Candidates Against Bovine Mastitis Caused By Staphylococcus Aureus, Sunghyun Yoon

Theses and Dissertations

Bovine mastitis is a significant disease affecting the dairy industry worldwide. The most frequently causative agent of contagious bovine mastitis is Staphylococcus aureus that produces numerous virulence factors contributing to its pathogenesis. However, it is not clearly defined which virulence factors play a critical role in bovine mastitis due to the heterogeneous virulence factor profiles in S. aureus isolated from different hosts and disease types. Among many virulence factors, it has long been postulated that staphylococcal cytotoxins and superantigens (SAgs) play an important role in the pathogenesis of S. aureus in bovine mastitis due to their potent toxicity toward host …

Discovery Of Antifungal Metabolites In Maize Cob Via Liquid Chromatography-Mass Spectrometry, Jeremy Ray Winders

Theses and Dissertations

Maize (Zea mays L.) is a global food staple and is at risk from infection by the pathogenic fungus Aspergillus flavus L. The ubiquitous, soil-borne fungus causes ear rot of maize and produces the carcinogenic secondary metabolite known as aflatoxin. Aflatoxin B1 is the most potent carcinogenic mycotoxin known, causing hepatocellular carcinoma, along with many other serious health problems such as immunosuppression. Previous studies have shown that maize cob tissue plays an essential role in both facilitating and limiting the spread of the fungal pathogen A. flavus, however, little attention in the literature has been given to the cob. To …

Distribution And Spread Mechanisms Of Chinese Tallow (Triadica Sebifera) At Multiple Spatial Scales Within Forests In The Southeastern United States, Shaoyang Yang

Theses and Dissertations

The coastal plain of the southeastern United States is historically wet pine savannahs, prairie, and hardwoods. However, many exotic species have invaded this area and become a serious threat to native forest ecosystems. Among those exotic species, Chinese tallow (Triadica sebifera) has become one of the most pervasive tree species in the southern coastal states, including Alabama, Mississippi, Louisiana, and Texas. Therefore, to understand the distribution and spread mechanisms has become important in the management and control of Chinese tallow in the southeastern United States. In this research, distribution and spread mechanisms of Chinese tallow were studied at multiple spatial …

Landscape Performance Of Callistemon Citrinus Under Environmental Stress Conditions, Riyadh Mannaa Mohsin

Theses and Dissertations

Woody ornamental plants are considered the key for well- designed landscapes; Callistemon citrinus is one of those plants. In arid and semiarid areas, Callistemon has been used in gardens and landscapes for its unique characteristics. This study was conducted to evaluate the performance of Callistemon in landscapes under different environmental stress conditions including water, and heat. Further, the potential of using 3D software SketchUp in landscape design was also investigated. Callistemon plants were grown under 100, 50 or 30% of field capacity with or without shredded hardwood mulch. When field capacity decreased, root: shoot ratio and water use efficiency were …

Municipal And Agricultural Wastewater Remediation Using Modified Biochars, Glenn Crisler Ii

Theses and Dissertations

Water contaminated by heavy metals and plant nutrients pose a threat to human health and safety as well as the environment. The aim of this body of work is to develop, characterize, and understand the adsorption properties of green sorbents to mitigate these risks. Biochar, an adsorbent known to be both environmentally friendly and inexpensive was used. Advantages of biochar are its high surface area, easy modification, and native surface functionality. Biochars used in this study are of pecan shell or douglas fir origin, although biochar can be made from a host of waste organic materials. Pecan shell biochar was …