Digital Commons Network^™

Elucidating Factors Affecting Cercosporin Production In Cercospora Leaf Blight Of Soybean To Develop Better Tools For Disease Management, Maria Izabel Costa De Novaes

LSU Doctoral Dissertations

Fungal toxins are pathogenicity/virulence factors for many plant diseases, including Cercospora leaf blight (CLB) of soybean (Glycine max (L.) Merr.). The pathogen, Cercospora cf. flagellaris, produces a perylenequinone toxin, cercosporin, which is activated by light to produce damaging reactive oxygen species. To identify novel solutions for CLB management, we studied factors that may impact the biology of cercoporin: fungal lipid droplets (LDs) and mineral and trace element composition (ionome) of the host. Furthermore, since artificial inoculation with the pathogen has been challenging, we also explored the usefulness of a previously developed cercosporin-based assay to study disease resistance. LDs …

Investigating Preferences And Behavior Within Environmental Economics, Sapana Bastola

LSU Doctoral Dissertations

To respond to the environmental problems posed by disposable plastic bags, several mechanisms exist, such as bag taxes and bans, but such policies are infeasible in several U.S. states and municipalities. This study uses a social quasi-experiment to examine the effect of a voluntary token-donation program, which reduces disposable plastic bag use by providing a small charitable donation incentive. We find that the token-donation program reduces the probability of disposable bag use by 11.4–12.9 percentage points, representing about a 30%–34% decrease in bag use. Our results demonstrate effective mechanisms to reduce plastic bags exist without government-mandated policy.

Despite the widespread …

Comparative Genomics And Virulence Studies Of Streptomyces Soil Rot And Scab Pathogen Species, Natasha Soares

LSU Doctoral Dissertations

Comparative genomic analyses were performed to gain insights into the organization and content of the genome of Streptomyces ipomoeae, the soil rot pathogen that infects sweetpotatoes. Unlike Streptomyces scab pathogens, the thaxtomin phytotoxin gene cluster (txt) in S. ipomoeae does not appear to reside within a genomic island and has diverged from its scab pathogen counterparts. Increased usage of the rare TTA codon, particularly for the txt cluster, suggests greater translational control by the bldA tRNA in S. ipomoeae. Orthologous gene searches and secondary metabolite profiling yielded ortholog groups and metabolite gene clusters that were exclusive …

The Effects Of Exercise On Innate Lymphoid Cell Metabolism And Function In Cancer, Eunhan Cho

LSU Doctoral Dissertations

Immunosenescence refers to the gradual decrease in immune competency over time, which is strongly associated with increased risk of cancer and a rise in morbidity and mortality among the elderly. Regular physical activity can be beneficial to the immune system by potentially decreasing the frequency of senescent immune cells and reducing mortality risk in cancer patients and survivors. However, less is known on the impact of acute exercise on “aggressive” cancers, such as hormone receptor negative breast cancers. Further, the mechanistic underpinnings of the exercise-associated improvements in the immune response to cancer remains unclear. In this context, past studies have …

Incorporating Geopolymer Binders To Fully Utilize Recycled Concrete Aggregates, Matthew Upshaw

LSU Doctoral Dissertations

This study aims to develop a geopolymer concrete binder that will yield desirable strength and durability characteristics when applied to recycled aggregate concrete. In order to achieve this, a geopolymer binder consisting of a metakaolin-silica fume aluminosilicate source material blend activated by potassium-based alkaline solutions is developed and used in place of ordinary Portland cement (OPC) with four different levels of recycled aggregate replacement ratios. The properties of these concretes were analyzed and compared with the properties of OPC concretes produced with the same replacement ratio levels. The results showed that the geopolymer recycled aggregate concrete (GRAC) achieved greater than …

Covid-19 In The United States As Affective Frame, John Protevi

Faculty Publications

In this paper I attempt to contribute to the developing field of “political philosophy of mind.” To render concrete the notion of “affective frame,” a social situation which pre-selects for salience and valence of environmental factors relative to a subject’s life, I conduct a case study of a deleterious socially instituted affective frame, which, during the early days of the COVID19 pandemic in the United States, produced individuated circumstances that came crashing down on “essential workers” who were forced into a double bind. We saw here an untenable and ultimately fatal situation that forced a choice between, on the one …

Insight In Thermomechanical Constitutive Modeling Of Shape Memory Polymers, Amir Shojaei, Wei Xu, Cheng Yan, Qianxi Yang, Guoqiang Li

Faculty Publications

Shape memory polymers (SMPs) are a new member of the smart materials family. SMPs have found wide applications or potential applications in almost all manmade structures and devices. In order to better design smart structures and devices using SMPs, thermomechanical constitutive modeling is essential. In this insight paper, we will focus on presenting several multi-length-scale and multi-physics modeling frameworks, including the thermodynamics consistent model, elasto-viscoplastic model, statistical mechanics model, and phase evaluation law model. The SMPs modeled will include amorphous one-way shape memory polymers, semicrystalline one-way shape memory polymers, semicrystalline two-way shape memory polymers, and functional and mechanical damage effects …

Ultraviolet Chiral Plasmonics, Tiago Ramos Leite Da Silva

LSU Doctoral Dissertations

The far- (λ < 250 nm) ultraviolet (UV) chiroptical response from protein secondary structures can aid in understanding protein interactions for drug discovery. Chiral metasurfaces have attracted attention to enhance the intrinsically weak biomolecular optical activity for improved structural biology characterization. However, due to materials and fabrication challenges, current metasurfaces mostly operate in the visible and near-infrared regimes with limited, if any, response in far-UV. The large spectral mismatch between metasurface and biomolecular resonances limits the chiral enhancement factor. In this work, we study aluminum planar metamaterials which display optical activity in the UV region. In the first part of this work, we experimentally and computationally investigate the resonant plasmonic-biomolecular interactions in the far-UV. To the best of our knowledge, our work is the first to experimentally explore these resonant interactions in the biologically relevant far-UV regime. We demonstrate experimentally and computationally enhanced chiral sensing of sub-10 nm amino acid films. We develop a full-wave computational model of a biomolecular film on an aluminum gammadion array using experimentally derived chiral parameters (κ) for L- and DTyrosine films. Our model shows that detectable enhancements in the circular dichroism (CD) and birefringence (CB) signals from small amounts of biomolecules are only possible when tight spectral overlap exists between the plasmonic and biomolecular chiroptical signals. We support this conclusion experimentally by fabricating aluminum gammadion arrays on fused silica substrates and sublimating ultrathin racemic, L- and D- Tyrosine films on the arrays. Complete Mueller matrix analysis of the resonant plasmonic-biomolecular system agrees with our computational results and demonstrates the importance of using far-UV active metasurfaces for enhancing natural optical activity. In the second part of this work, we study hybrid aluminum reflective metasurfaces, which leverage both local and propagating surface plasmons (PSP). These materials display strong bi-anisotropy with rich polarization conversion properties. We explore several geometries and verify how their symmetry properties affect their far-field response. Our observations provide an opportunity for researchers to improve the chiral response of plasmonic metasurfaces, especially in the challenging ultraviolet regime.

Relational Turbulence And Social Network Engagement During The Summer Of Covid-19: A Repeated Measures, Dyadic Analysis, Kellie S. Brisini, Denise H. Solomon

Faculty Publications

Background/Purpose: Relational turbulence theory suggests that changes in and around relationships create the potential for relational turbulence when everyday routines and scripts are upended and communication becomes polarized. In turn, perceptions of a romantic relationship as chaotic or tumultuous can influence a person’s engagement with their social network. Alternately, previous research also suggests that engagement with friends and family has the potential to influence married partner’s relationship quality. Research Design: This study examined these propositions among a sample of married couples (N = 64, 128 individuals) whose daily experiences and relationship dynamics changed during the COVID-19 lockdown period. Results/Conclusions: Based …

Icam-1 Abundance Is Increased In Pancreatic Islets Of Hyperglycemic Female Nod Mice And Is Rapidly Upregulated By Nf-Κb In Pancreatic B-Cells, Thomas M. Martin, Susan J. Burke, Heidi M. Batdorf, David H. Burk, Sujoy Ghosh, Samuel D. Dupuy, Michael D. Karlstad, J. Jason Collier

Division of Basic Science Faculty Publications

Type 1 diabetes (T1D) is classified as an autoimmune disease where pancreatic b-cells are specifically targeted by cells of the immune system. The molecular mechanisms underlying this process are not completely understood. Herein, we identified that the Icam1 gene and ICAM-1 protein were selectively elevated in female NOD mice relative to male mice, fitting with the sexual dimorphism of diabetes onset in this key mouse model of T1D. In addition, ICAM-1 abundance was greater in hyperglycemic female NOD mice than in age-matched normoglycemic female NOD mice. Moreover, we discovered that the Icam1 gene was rapidly upregulated in response to IL-1β …

Bio-Inspired Geotechnical Engineering: Principles, Current Work, Opportunities And Challenges, Alejandro Martinez, Jason Dejong, Idil Akin, Ali Aleali, Chloe Arson, Jared Atkinson, Paola Bandini, Tugce Baser, Rodrigo Borela, Ross Boulanger, Matthew Burrall, Yuyan Chen, Clint Collins, Douglas Cortes, Sheng Dai, Theodore Dejong, Emanuela Del Dottore, Kelly Dorgan, Richard Fragaszy, J. David Frost, Robert Full, Majid Ghayoomi, Daniel I. Goldman, Nicholas Gravish, Ivan L. Guzman, James Hambleton, Elliot Hawkes, Michael Helms, David Hu, Lin Huang, Sichuan Huang, Christopher Hunt, Duncan Irschick

Faculty Publications

A broad diversity of biological organisms and systems interact with soil in ways that facilitate their growth and survival. These interactions are made possible by strategies that enable organisms to accomplish functions that can be analogous to those required in geotechnical engineering systems. Examples include anchorage in soft and weak ground, penetration into hard and stiff subsurface materials and movement in loose sand. Since the biological strategies have been 'vetted' by the process of natural selection, and the functions they accomplish are governed by the same physical laws in both the natural and engineered environments, they represent a unique source …

Qualifying Factors That Predict Weight Loss Success Within Diet Interventions, Jordan Losavio

LSU Master's Theses

Evidence-based diet strategies lead to weight loss for some, while for others, the same diet approach could result in trivial weight loss or even in weight gain. This prompts the underlying research question: what factors predict that a given diet strategy will be efficacious for some, but not for others? This research was a secondary analysis of clinical weight loss studies to determine which factors influence an individual’s weight loss success for three diet intervention strategies: low-carbohydrate, low-fat, and low-calorie. A combination of physiological, psychological, behavioral, and dietary factors was evaluated for each diet study. Multiple linear regression and logistic …

“Not Nearly What It Used To Be”: A Mixed Methods Study On Hazing And Organizational Culture In Historically White Fraternities, Kimberly Rogers Davis

LSU Doctoral Dissertations

Hazing is a significant concern on college campuses, especially as students continue to die following hazing incidents in student organizations. Fraternities, particularly historically White fraternities (HWFs), have been the site of many recent hazing deaths. However, fraternity and sorority life leaders and advocates often argue that the chapters where hazing tragedies occur are the minority in a broader system that offers numerous contributions to society. Rather than a fraternity or sorority problem, hazing may result from cultural influences within and around the organization. Thus, the purpose of this study is to understand how organizational culture, such as chapter culture and …

Aphid Herbivory On Industrial Hemp, Cannabis Sativa L., And The Impact Of Plant-Soil Feedbacks On Hemp Performance In Louisiana, Alex Leede

LSU Master's Theses

Industrial hemp, Cannabis sativa L., is defined as having less than 0.3% delta-9-tetrahydrocannabinol by dry weight. It can be grown for fiber, food, oil, and cannabinoids. As a newly legalized crop, little research exists regarding the cultivation or pest management practices in Louisiana. The versatility of industrial hemp may allow for substantial future production in Louisiana. This project set out to understand the impact of previous crops on hemp performance and soil microbial communities. Soybean, Glycine max L. (Merr), grain sorghum, Sorghum bicolor (L.) Moench, and sweetpotato, Ipomeae batatas (L.) Lam, were selected as soil conditioning crops because they are …

Soil Moisture Mediated Behavioral And Physiological Alterations Of Coptotermes Formosanus And Reticulitermes Flavipes (Blattodea: Rhinotermitidae), Steven J. Richardson

LSU Master's Theses

Substrate moisture is a critical environmental factor for the survival and behavior of subterranean termites (Blattodea: Rhinotermitidae). The invasive Formosan subterranean termite (Coptotermes formosanus) and the native eastern subterranean termite (Reticulitermes flavipes) co-occur in the southeastern United States, but C. formosanus is predominant in subtropical and R. flavipes is more common in temperate regions. The difference in their geographic distributions is largely attributed to their different behavioral and physiological ecology. While ample research has been done on foraging behavior of the two species, there was no empirical evidence for the effects of constant soil moisture on …

Numerical Modeling Of Pile Responses Under Lateral Loading Considering The Scour Effects, Jungmin Lee

LSU Master's Theses

This thesis focuses on the 3D numerical analysis of the laterally loaded pile. For numerical modeling/analysis, ABAQUS, a widely used commercial software, is used. Non-scour and scour conditions are considered for this thesis. Two elastoplastic constitutive models, Mohr-Coulomb model and Cam Clay model, are applied. Unknown material and interface properties are calibrated based on two references which explained the numerical analysis of the laterally loaded pile under the non-scour condition. Different cases of scour depth, S_d, scour width, S_w, and scour slope angle, a, are applied for the laterally loaded pile analysis under the scour …

The Relationship Between Family Environment And Specific Phobias, Jerrica Renee Guidry

LSU Doctoral Dissertations

Specific phobias are the most prevalent disorder among adults and highly common among children. Additionally, specific phobias diagnosed in childhood has been associated other serious mental illnesses later in life (de Vrie et al., 2019). Research pertaining to parenting factors associated with anxiety disorders has been extensive, including parental psychopathology, parent-child relationships, parental control, and parental stress. However, less emphasis has been placed on familial factors which may contribute to the development and maintenance of specific phobias. According to the limited literature focusing on the family factors associated with specific phobias, parent psychopathology and parent over-control are important factors. Multiple …

Understanding Children's Museums' Approaches To Diversity: A Critical And Socio-Cultural Investigation, Amber Nicole Smith

LSU Doctoral Dissertations

Children begin to develop self-awareness and awareness of others at an early age (Marion, 2011). Before they reach kindergarten, children begin to make distinctions about race by noticing similarities and differences between themselves and others (Winkler, 2009). Exposing young children to diversity can help each child embrace their identity, accept and celebrate differences, and be accepting of themselves and others (Cole & Verwayne, 2018).

The purpose of this study is to explore how children’s museums support diversity through their programs and planning. The research of this study focuses on four children’s museums located in the United States. There are many …

War And Peace: Grant's Peace Policy In Indian Territory And The Upper Plains, Abigail Gardner

LSU Master's Theses

Ulysses S. Grant’s tenure as United States President from 1869 to 1877 saw the creation of a new federal Indian Policy, dubbed the Peace Policy. Grant’s goal was to end hostilities between not only the US government and Natives, but between the general populace and Natives. His policy included the creation of the Board of Indian Commissioners, continuation of the reservation system, assimilation, and ending the treaty system. His plans for peaceful coexistence did not come to fruition. This thesis assesses why the Peace Policy was a failure and does so by comparing the results among the Five Tribes of …

Factors Associated With Racial And Ethnic Minority Youths' Mental Health Help-Seeking At School, Sam Allouche

LSU Doctoral Dissertations

Despite the high prevalence and associated consequences of mental health problems in youth, adolescents with these problems are often left untreated. This service gap is even greater in racial and ethnic minority youth who not only engage in treatment less frequently, but also experience far greater discrimination and systemic inequality than non-ethnic or racial minority students; factors further contributing to a need for service. Schools may provide an ideal location to treat mental health problems in youth, in part because schools eliminate structural barriers, but also because school staff have an opportunity to observe students across a range of functioning. …

Chloride Channels That Mediate A Transient Nitric Oxide-Dependent Synaptic Polarity Switch In Retinal Amacrine Cells., Tyler Christopher Rodriguez

LSU Doctoral Dissertations

Cytosolic chloride (Cl^-) concentration determines whether GABAergic and glycinergic synapses are inhibitory or excitatory. Ionotropic GABA and glycine receptors passively conduct Cl­^- leading to membrane depolarization or hyperpolarization depending on the Cl^- equilibrium potential. Accordingly, the distribution of Cl^- across the plasma membrane has the potential to determine the properties of networks of retinal amacrine cells (ACs) and their postsynaptic partners. Ion channels are responsible for establishing Cl^- reversal potential. Nitric oxide (NO) is a signaling molecule that can be generated in the inner retina where ACs form synapses. We have shown that NO …

Breeding Ecology Of Mottled Ducks In Southwestern Louisiana, Elizabeth Sophia Bonczek

LSU Doctoral Dissertations

Mottled ducks are a resident species found in the southern United States that rely on coastal marsh and associated habitat to fulfill the needs of the entirety of their annual cycle. Population monitoring has revealed declines in western Gulf Coast (WGC) mottled ducks since 2008. Mottled duck populations are influenced by survival and recruitment, and changes in these factors may contribute to population declines. The overarching goal of this project was to identify the mechanisms potentially limiting WGC mottled ducks.

I captured adult female mottled ducks during molt on Rockefeller Wildlife Refuge and adjacent lands in southwestern Louisiana from 2017–2019. …

A Wet/Dry Point Treatment Method Of Fvcom, Part Ii: Application To The Okatee/Colleton River In South Carolina, Changsheng Chen, Haosheng Huang, Huichan Lin, Jack Blanton, Chunyan Li, Francisco Andrade

Faculty Publications

The wet/dry point treatment method of FVCOM was applied to simulate the tide-induced flooding/drying process in the estuarine–tidal-creek–saltmarsh complex of the Okatee/Colleton River Estuary, South Carolina. The simulation results were compared with observed currents at three mooring sites and flooded areas observed from remote-sensing hypsometric measurements, demonstrating that FVCOM can robustly reproduce tidal and residual currents in the river and the flooding process onto the intertidal saltmarsh. The simulated flow field reveals that the Okatee/Colleton River Estuary is characterized by multiple residual eddies. Driven by the periodic tidal forcing, this estuarine system features a chaotic water transport process. Numerous residual …

The Alpha-7 Nicotinic Acetylcholine Receptor Agonist Gts-21 Engages The Glucagon-Like Peptide-1 Incretin Hormone Axis To Lower Levels Of Blood Glucose In Db/Db Mice, Qinghe Meng, Oleg G. Chepurny, Colin A. Leech, Napat Pruekprasert, Megan E. Molnar, James Jason Collier, Robert N. Cooney, George G. Holz

Division of Basic Science Faculty Publications

Aim: To establish if alpha-7 nicotinic acetylcholine receptor (α7nAChR) agonist GTS-21 exerts a blood glucose-lowering action in db/db mice, and to test if this action requires coordinate α7nAChR and GLP-1 receptor (GLP-1R) stimulation by GTS-21 and endogenous GLP-1, respectively. Materials and Methods: Blood glucose levels were measured during an oral glucose tolerance test (OGTT) using db/db mice administered intraperitoneal GTS-21. Plasma GLP-1, peptide tyrosine tyrosine 1-36 (PYY1-36), glucose-dependent insulinotropic peptide (GIP), glucagon, and insulin levels were measured by ELISA. A GLP-1R–mediated action of GTS-21 that is secondary to α7nAChR stimulation was evaluated using α7nAChR and GLP-1R knockout (KO) mice, or …

Was The Decline Of Saltmarsh Tabanid Populations After The 2010 Oil Spill Associated With Change In The Larval Food Web?, Claudia Husseneder, Devika R. Bhalerao, Lane D. Foil

Faculty Publications

Horse flies of the species Tabanus nigrovittatus and Tabanus acutus are native to coastal marshlands. Their larvae are apex invertebrate predators, and their development is dependent on the food web in the marsh sediment. Surveillance of T. nigrovittatus after the 2010 Deepwater Horizon Oil Spill in the Gulf of Mexico showed population crashes of adult flies in southeast Louisiana marshes near oil landfall, but not in southwest Louisiana where oil did not reach. Sediment collection in 2011 from Louisiana marshes showed a near-complete absence of larvae in the southeast yet high numbers in the southwest. We hypothesized that oil contamination …

Louisiana Agriculture Summer, 2022

Louisiana Agriculture

LSU AgCenter researchers constantly search for ways to improve Louisiana agriculture by increasing yields and profitability. They also seek to understand new and less popular crops that could thrive in our region. Professor Yan Chen is helping develop the tea industry along the Gulf Coast, working closely with producers to understand how to grow tea (Camellia sinensis) in the region, and her work is featured in the latest issue of Louisiana Agriculture magazine. The magazine also includes a look into Grow Louisiana and Growing Farmers, two programs designed to help beginning farmers learn the business. Researchers from the …

Event Based Approach For Modeling Indoor Airflow Patterns, Ehsan Mousavi, Arup Bhattacharya

Faculty Publications

People spend a significant proportion of their time indoors, where the quality of indoor air affects the productivity, efficiency, and well-being of occupants. One of the oldest challenges in building construction is designing a ventilation system that ensures optimum indoor air quality. Acceptable indoor air should provide thermal comfort and minimize human exposure to contamination. Characterizing these two elements requires information on both heat/mass transfer in the microenvironment and the time-specific activity of individuals who move among these microenvironments. While researchers have utilized simulation tools to investigate this complex human-environment interaction, current numerical techniques severely limit the simulations to overly …

Ethnic Discrimination And Alcohol-Related Problem Severity Among Hispanic/Latin Drinkers: The Role Of Social Anxiety In The Minority Stress Model, Julia D. Buckner, Elizabeth M. Lewis, Justin M. Shepherd, Michael J. Zvolensky

Faculty Publications

Introduction: Hispanic/Latin individuals in the U.S. experience many health disparities, including worse alcohol-related outcomes. Thus, identifying psycho-sociocultural factors that may play a role in alcohol-related problems among these individuals is vital to informing prevention and treatment efforts. Minority stress-based models of alcohol misuse posit that some Hispanic/Latin individuals may drink (and continue to drink despite drinking-related problems) to alleviate negative affect associated with experiencing ethnic discrimination. Yet, little research has directly tested this hypothesis. Given the social nature of both ethnic discrimination and drinking, it follows that experiencing more ethnic discrimination could be related to greater social anxiety and some …

The Covid-19 Pandemic And Associated Increases In Experiences Of Assault Violence Among Black Men With Low Socioeconomic Status Living In Louisiana, Kaylin Beiter, Denise Danos, Erich Conrad, Stephanie Broyles, Jovanny Zabaleta, Jason Mussell, Stephen Phillippi

Population and Public Health Science Faculty Publications

Background: The COVID-19 pandemic has had mental health, social, and economic implications among communities with high levels of social disadvantage; this may have impacted community violence rates. The objective of this study was to characterize overall trends in assault and social disadvantage of patients experiencing assault before and during the COVID-19 pandemic. Methods: All trauma activations at a level one trauma center serving the entire southeast Louisiana region were included during March–August pre-COVID (2018–2019) and during COVID (2020). ICD-10 E-codes were used to identify trauma intent (assault vs. other). Assaults in this context are defined as physical injuries caused by …

Alliance Of Randomized Trials Of Medicine Vs Metabolic Surgery In Type 2 Diabetes (Armms-T2d): Study Rationale, Design, And Methods, Donald C. Simonson, Bo Hu, David E. Arterburn, Philip R. Schauer, Sangeeta R. Kashyap, Anita P. Courcoulas, David E. Cummings, Mary Elizabeth Patti, William F. Gourash, Ashley H. Vernon, John M. Jakicic, John P. Kirwan

Division of Basic Science Faculty Publications

Aims: Long-term data from randomized clinical trials comparing metabolic (bariatric) surgery versus a medical/lifestyle intervention for treatment of patients with obesity/overweight and type 2 diabetes (T2D) are lacking. The Alliance of Randomized Trials of Medicine vs Metabolic Surgery in Type 2 Diabetes (ARMMS-T2D) is a consortium of four randomized trials designed to compare long-term efficacy and safety of surgery versus medical/lifestyle therapy on diabetes control and clinical outcomes. Materials and Methods: Patients with T2D and body mass index (BMI) of 27-45 kg/m2 who were previously randomized to metabolic surgery (Roux-en-Y gastric bypass, adjustable gastric band, or sleeve gastrectomy) versus medical/lifestyle …