AUETD (Auburn University)
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Creating a 3D Engineered Tissue Model to Mimic Colorectal Cancer Microenvironment for Studying Chemokine and Fibroblast in Cancer Progression
No full textColorectal cancer (CRC) is the second leading cause of cancer-related death worldwide with a higher incidence in US. Among its subtypes, the consensus molecular subtype 4 (CMS4) is known to be the most aggressive, characterized by high stromal infiltration and an abundance of fibroblasts. CRC progression is heavily influenced by the tumor microenvironment (TME), particularly through secreted chemokines that regulate inflammation, angiogenesis, and tissue remodeling. One such chemokine, CXCL7, has emerged as a key factor in promoting pro-tumorigenic signaling. In our initial study, the role of CXCL7 was investigated in HT29 CRC progression within a three-dimensional (3D) culture environment. Elevated CXCL7 expression was associated with increased cell proliferation, larger colony size, and greater tissue growth and survival in the 3D construct. These results reinforce the role of CXCL7 as a critical mediator in colorectal cancer progression and highlight its potential as a therapeutic target in modulating the inflammatory and proliferative components of the TME. Additionally, 3D colon cancer tissues were engineered using HT29 cells in coculture with BJ5ta fibroblasts at varying ratios (1:0, 1:1, and 1:5) to better recapitulate the 3D TME and to evaluate the impact of fibroblasts on tumor progression, particularly whether CMS3-like cancer could transition toward a more aggressive cancer subtype. The engineered tissues were used to study the morphological changes, colony formation, mechanical properties, and proliferation. The results showed that coculture with fibroblasts, especially at a 1:5 ratio, significantly altered the tissue structure, leading to more compact and larger colonies along with increased stiffness compared to monoculture. These outcomes aligned with the hypothesis and suggest that fibroblast-induced changes in the TME may play an important role in CRC progression, offering future potential for use in testing therapeutic targeting
Revealing Peanut Drought Tolerant Mechanisms by Integration of Physiological Traits, Soil Microbes, and Genomics
No full textPeanut production is increasingly challenged by frequent and severe drought events worldwide. Rather than relying on costly irrigation systems, cultivating drought-tolerant cultivars offers a more sustainable approach for agricultural resilience. While some drought-tolerant genotypes have been previously identified, a deeper understanding of the mechanisms behind drought tolerance is necessary to support breeding efforts. Effective drought tolerance strategies in peanuts include enhanced biological nitrogen fixation (BNF), inoculation with rhizobia with high 1-Aminocyclopropane-1-carboxylate (ACC) deaminase activity, partial stomatal closure to reduce water loss, and maintenance of higher stomatal conductance under drought through growing deeper root systems. From 2019 to 2022, a series of field and greenhouse experiments were conducted to explore these drought tolerance mechanisms. Our findings indicate that increased BNF in a specific number of drought-tolerant cultivars contributes to higher yields under drought with concomitant maintenance of higher leaf water status, as indicated by relative water content, being critical for optimal BNF performance. While the inoculation effect of strains with ACC deaminase on drought tolerance was not significant, peanut plants inoculated with strains carrying acdS genes showed improvements in root biomass and BNF under well-watered and drought conditions. Significant genotypic differences in root morphology traits, such as root angle, number of root tips, and average root diameter, were observed in field experiments under irrigated and rainfed conditions. Drought tolerant cultivars, AU-NPL 17 and AU18-35, exhibited steeper root angles supporting other evidence that classified these cultivars as water-spender cultivars. In the study of detection of drought tolerance related quantitative trait loci (QTLs) from an F2 population, significant reductions were observed in yield, shoot biomass, harvest index (HI), photosynthesis, stomatal conductance, and C13 in parent and F1 populations in 2021 under drought. However, AP-3 exhibited superior performance in the single plant setting, demonstrating reduced sensitivity to drought stress. The linkage map was constructed with 471 markers on 20LGs covering 1403.33cM and with an average inter-marker distance of 2.98cM. A total of 27 QTLs associated to physiological traits (pod count, shoot, HI, C13, N15, photosynthesis, stomatal conductance and SPAD) related to drought tolerance were detected in F2 experiment. These identified QTLs could aid in better characterizing drought-tolerant genomic regions and improve marker-assisted selection for these traits in peanut breeding programs for drought-tolerant genotypes
The Combined Impact of Lairage Temperatures and Controlled Atmosphere Gas Stunning time on Meat Quality and Blood Metabolites
No full textLairage, a holding area where poultry are kept prior to slaughter and controlled
atmosphere stunning (CAS) are two factors associated with poultry processing that can influence
both the physiological state of a bird, and the quality of the meat produced. Despite this, the
possible impacts of both lairage temperatures and CAS together are widely unexplored.
Understanding the potential effects is imperative to improving processing plant efficiency,
enhancing meat quality, and optimizing processing conditions. For this study, the effect of
lairage temperature and CAS on broiler breast meat quality and blood metabolites was
investigated. A 2x2 experimental design was used to evaluate two simulated lairage
environments (hot: 28.9°C and cool: 17.3°C) and two stunning durations (4.5 and 6 minutes).
Broilers were exposed to the simulated lairage conditions for 1 hour. Blood samples were taken
pre-lairage, post-lairage pre-stun, and post-stun. Using an iSTAT Alinity v, 13 blood metabolites
were evaluated: PCO2 (mmHg), pH, PO2 (mmHg), HCO3
- (mEq/L), SO2 (%), TCO2 (mEq/L), Na
(mEq/L), iCa (mmol/L), glucose (mg/dL), hematocrit (%PVC), and hemoglobin (g/dL).
Following lairage birds were stunned using CAS and processed normally. After immersion
chilling and deboning, breast fillets were evaluated at 2 and 24 h for pH, color, and drip loss. At
24 h and 7 d lipid oxidation readings were taken. At 2 h postmortem, birds stunned for 4.5 min
had higher pH than those stunned for 6 min (P = 0.027), and at 24 h, birds from the cooler lairage
environment had higher pH than those from the hot environment (P < 0.0001). Fillets from hot
lairage birds were lighter and more yellow at both 2 h and 24 h postmortem compared to cool
birds (P =0.0008). No differences were observed for drip loss or lipid oxidation. CAS time
significantly affected blood gases (HCO₃⁻, pH, PCO₂, SO₂), electrolytes (Na, iCa), and glucose
(P < 0.0001), with a glucose and hemoglobin interaction observed between lairage temperature
2
and CAS time (P = 0.034, P = 0.046). Hematocrit was higher in the 4.5-minute stunned birds (P
= 0.008). This work aims to investigate how different lairage temperatures and CAS can
influence broiler meat quality and blood chemistry, ultimately providing valuable insights for
improving poultry processing practices
Exploring Parasite Diversity: Taxonomic Studies of Parasites from Birds, Crocodilians, and Anurans Across Diverse Ecosystems
No full textThe overall objective of this dissertation was to apply modern taxonomic and molecular phylogenetic methods to understanding “hidden” (undiscovered) parasite diversity in common wildlife species. The specimens described herein were collectedly sourced from parasitological collections and expeditions in the Southeastern United States (Alabama, Louisiana, South Carolina, Georgia, Mississippi) as well as sub-Saharan Africa (Namibia, Mozambique, South Africa, Botswana).
The Southeastern United States is a center of biodiversity for numerous aquatic invertebrate and vertebrate taxa, including mollusks that are the critical first intermediate host for nearly all lineages of trematodes (Platyhelminthes, Digenea; the focus parasite group of the dissertation). We think that the parasite groups infecting these diverse aquatic hosts are correspondingly diverse. Alabama is an ideal geographic locality to study the parasites of aquatic and semi-aquatic wildlife. Because, all free living organisms have some parasites, and despite many researchers writing big grants and traveling far from the United States to collect parasites, the parasites that infect American wildlife species remain under-sampled and under-explored.
Sub-Saharan Africa is a renowned region of the world for its diversity of charismatic megafauna. It is less surveyed the parasites that infect them. This dissertation includes results from opportune necropsies of rarely examined water birds (white-backed and fulvous whistling ducks), which were infected by a new lineage (genus) of bird trematode, as well as an extremely fortunate opportunity to necropsy a fresh-killed Nile crocodile in cooperation with the Namibian Department of Conservation. Again, while the Nile crocodile is an iconic wildlife species in Africa, our examination of a single individual resulted in exciting parasitological discoveries.
Each chapter of this dissertation explores the taxonomic identity and phylogenetic interrelationships, and the Discussion sections and Taxonomic Remarks sections of the works detailed below include components of ecosystem health, ecosystem indicators, host health, biogeography, and host-parasite cophyly.
For Chapter 1, In North America, we discovered Anativermis normdroneni n. gen., n. sp., in a Canada goose from Alabama—the first record of a cyclocoelid in this host and region. Cyclocoelids are trematodes (Cyclocoelidae) that primarily parasitize the air sacs and body cavities of birds, particularly waterfowl. Despite their presence in common bird species, many cyclocoelids remain inadequately studied, with new genera and species still being described, underscoring the need for further research. For Chapter 2, In Namibia, our survey of birds in ephemeral systems led to the first record of Dendritobilharzia pulverulenta in sub-Saharan Africa, infecting white-backed and fulvous whistling ducks. This also marked the first description of a female of D. pulverulenta from the continent where it was originally described. For Chapter 3, Similarly, we found Dracovermis occidentalis, an elusive liolopid digenean, in an American alligator from Alabama after nearly half a century without mention of the species. American alligators are charismatic megafauna that have been extensively studied, making the discovery of this seldom-found trematode quite surprising. For Chapter 4, In Africa, we discovered Ngubuvangandu francoisjacobsi n. gen., n. sp., in a Nile crocodile in Namibia, expanding our knowledge of crocodilian liolopids and reshaping their taxonomic grouping. This discovery underscores how much remains to be understood about crocodilian parasitology, even in species that are frequently examined, and emphasizes the need for ongoing exploration in well-studied wildlife populations. For Chapter 5, Furthermore, we identified Latergator louisdupreezi n. gen., n. sp., infecting the eye of an alligator in Louisiana. The discovery of a polystomatid on an alligator is significant, as it represents the first record of a polystomatid infecting a crocodilian. This broadens our understanding of the host range of these parasites and provides new insights into parasitic relationships in reptiles. For Chapter 6, In amphibians, we redescribed Polystoma nearcticum from Cope’s gray treefrogs in Alabama, with molecular data suggesting the need for a new genus to accommodate North American treefrog polystomatids.
These discoveries, while occurring in different regions and hosts, share common themes: overlooked parasite diversity, host-parasite relationships that exceed geographic boundaries, and the continued need for taxonomic and molecular research to classify these organisms accurately. The fact that these parasites remained undiscovered or need to be redescribed in frequently studied animals highlights how much remains to be learned about parasite biodiversity, even in well-surveyed ecosystems. These findings underscore the vast, hidden world of parasites that remains to be explored, regardless of location
Challenges and Opportunities for Promoting STEM Persistence Within Introductory Physics
No full textStudent attrition in STEM (Science, Technology, Engineering, and Mathematics) programs is a prevailing issue affecting academic institutions across the United States. This dissertation focuses on understanding the mechanisms relating to STEM persistence and highlights the opportunities to help promote student retention in these vital academic programs within introductory physics. Chapter 2 presents a comparative study of student persistence following both active-learning and traditional lecture formats for an introductory engineering physics 1 course. We found statistically higher rates of one-year persistence in the active-learning format compared with the lecture format. While a positive correlation existed, we could not see which students were being affected by the active-learning format and how. Thus, in the following study we collected social interaction data for a course using the same active-learning format to study how these dynamics shaped students’ sense of belonging which is understood to be an individual's feeling of connectedness or acceptance within a group—a known factor correlated with persisting in STEM. The interaction data showed that students in groups of two or more people that was configured such that they were interacting with every other person and others were interacting with them or strongly connected reported higher levels of sense of belonging than those who were isolated or not strongly connected. The final study discussed the development and implementation of a supplemental intervention for an introductory physics 1 course for life-science majors focusing on deliberate practice or effortful practice meant to refine a particular skill and just in time feedback which is immediate feedback after an action for real-time improvement. To quantify the efficacy of this intervention we compared the performance of students who attended versus those who did not on a standardized course final exam delivered by the physics department to see if we could measure any effect. Controlling for incoming preparation and social/psychological factors like self-efficacy and mindset towards intelligence, we found that students who attended the intervention performed better despite entering the course with lower self-efficacy and physics knowledge. Together, this work aims to expand our understanding on the mechanisms affecting STEM persistence and highlights opportunities and strategies within introductory physics to reduce student attrition
Pathways to Learning: A Retrospective Study of Adult Education and Motivation Among Formerly Incarcerated Women
Get PDFThis qualitative grounded theory study explores the educational motivations, deterrents, and decision-making processes of incarcerated adult learners, with a focus on women previously incarcerated in Alabama at Tutwiler Prison. Rooted in adult education theory and supported by a Social Constructivist perspective, the research underscores the transformative potential of correctional education while illuminating the systemic, environmental, and personal barriers that hinder educational engagement in prison settings. Drawing on in-depth, semi-structured interviews conducted at the Lovelady Center in Birmingham, Alabama, and supported by thematic analysis through software like Atlas.ti, the study reveals a complex interplay of intrinsic and extrinsic motivators shaping formerly incarcerated learners’ engagement in education.
Adult education, defined as formal and informal learning opportunities for individuals aged 24 and older, provides the foundation for this investigation. The study highlights the principles of adult education including practical application, readiness to learn, the value of life experience, self-directed learning, intrinsic motivation and relevance to real-world goals as central to understanding motivation within correctional environments. Key motivational theories such as Self-Determination Theory, Expectancy Value Theory, and Mastery Goal Orientation were applied to examine how previous incarcerated adults perceive and engage with educational opportunities.
Findings indicate that incarcerated adult learners are often motivated by personal aspirations, family responsibilities, and the desire for reintegration and employability upon release. Conversely, barriers such as addiction, emotional fatigue, prior negative academic experiences, institutional inefficiencies, and unsanitary living conditions frequently undermine motivation.
This study also documents the positive influence of supportive adult educators, safe and engaging learning environments, and the availability of practical career-oriented educational programming. Participants described how leaving the pod or receiving better meals enhanced their sense of agency and belonging, reinforcing the value of education.
Importantly, the research contributes to the discourse on adult education by identifying the necessity of designing educational programs that are relevant, accessible, and responsive to the diverse experiences and goals of incarcerated adults. It underscores the need for correctional institutions to expand program offerings, reduce scheduling delays, train adult education practitioners in trauma- informed and motivational strategies, and create equitable learning environments. The findings advocate for integrated support systems that combine education with mental health services, addiction recovery, and peer mentoring, thereby fostering holistic rehabilitation.
Ultimately, this study emphasizes that adult education within correctional settings holds significant promise for reducing recidivism, promoting personal growth, and improving societal reintegration outcomes. Future research should broaden the scope to include male incarcerated learners, diverse regional and international contexts, and longitudinal data to capture the sustained impact of correctional education. The insights gained can inform policy and practice to make correctional education a more effective, empowering tool for transformation and reintegration, reinforcing its critical role within the broader field of adult education
Reliability Operations of The Tomia Island Microgrid
Get PDFIndonesia’s electrification ratio remained stagnant at 99.2% in 2020, largely due to its geographical challenges. Many areas still lack electricity, especially those located far from transmission lines or on small islands, where installing new infrastructure would be prohibitively expensive. For these remote communities, microgrids present an ideal solution. However, most existing microgrids rely on diesel generator sets to produce electricity. The high cost of diesel fuel limits electricity availability, with some microgrids only supplying power at night, leaving homes and businesses without electricity during the day. To address this issue, photovoltaic power plants have been introduced. While this helps reduce reliance on diesel, integrating inverter-based resources into a microgrid lowers its inertia, making it more vulnerable to instability during disturbances. Furthermore, continued use of diesel generators contributes to higher carbon emissions, posing environmental concerns that must be addressed for a more sustainable energy future.
This study focuses on the microgrid of Tomia Island, a small island in eastern Indonesia. The island's microgrid has 23 buses and mainly relies on diesel generators for power. To provide electricity all day, four solar power plants were added to the system. To make the microgrid more reliable and reduce the use of diesel, wind turbines, pumped storage hydropower (PSH), and a grid-forming inverter were introduced. Load-shedding techniques were also used to keep voltage and frequency stable during disturbances.
Simulations were conducted using PSCAD/EMTDC to test these improvements. Results showed that the microgrid stayed stable during events like three-phase faults, PSH trips, and diesel generator (DG) trips. It also showed potential for expansion, handling more loads with proper control. With load management, inertia, and damping adjustments, the microgrid's voltage and frequency stayed within acceptable limits during unexpected islanding or generator trips
Toxicological analysis of Lipid-Based Nanoparticles: A Comparative Study
No full textLipid-based nanoparticles (LNPs) are frontliners in nanomedicine, as their use as mRNA carriers and in drug delivery has become prominent over the years. Despite their increasing application in medicine, there are limited studies on their potential toxicity or on any adverse effects that could be associated with them. Also, growing concerns about their toxicity have moderated their clinical translation. This study elucidates the potential toxicological behavior of three lipid-based nanoparticles. Lipid based nanoparticles are divided into two major groups based on the charge of their head group. These include Cationic Lipid nanoparticles (cLNPs) which are positively charged and Ionizable Lipid Nanoparticles (iLNPs) which are neutral, but they take on the charge of the environment they are. Both systems are emerging as promising tools for the delivery of therapeutic drugs, including nucleic acids.
In our toxicity studies of Lipid-based nanoparticles, firstly, we carried out comparative in vitro analysis and animal studies using cLNPs (Liposomes and jetMESSENGER) and iLNPs (Nanostructure Lipid Carriers – NLCs). Secondly, we employed RNA sequencing and transcriptomics analysis. RNA seq analysis was done due to inconsistent outcomes often observed with the results from in vitro studies, suggesting the cruciality of more studies on the molecular level. In vitro toxic effects of all three LNPs were evaluated based on oxidative stress, cell viability, cell proliferation, programmed cell death and cell morphology. We treated Chinese hamster ovary (CHO) cells, a mammalian cell line, with the LNPs to measure the production of reactive oxygen species (ROS). Cell viability was ascertained with trypan blue exclusion assay. Flow cytometry was used to analyze cell apoptosis and necrosis. Moreover, the cell proliferation assay, Alamar blue assay, was used to study the metabolic activity of LNP treated cells by using resazurin, a non-fluorescent dye to measure NADH production. Being an acute toxicity study, two exposure periods, 4 h and 24 h, were considered.
For animal studies, serum from blood samples that were collected from mice after 24 h intramuscular and intravenous injection with NLCs and NLC with eGFP-mRNA encapsulation. Specific enzymes, i.e. aspartate transaminase –AST and alanine transaminase –ALT, were used as biomarkers, because increase in their level could be indicative of specific organ or cell damage. Results from our in vitro study showed that cells treated with the LNPs compared to the control induced some level of cytotoxicity, although there was no significant increase in ROS level after 24 h. Meanwhile, animal assessment showed no significant toxicity when LNPs were intravenously administered compared to intramuscular administration.
In the RNA-Seq study, RNA from human lung fibroblasts (WI-38) that were treated with LNP-eGF-mRNA for 24 h, was sequenced. The mRNA transcripts of exposed cells were compared to transcripts from untreated and differentially expressed genes generated with bioinformatics tools. Exposure of WI-38 cells to LNP-mRNA led to specific changes in the expression of genes associated with immune response, inflammation, cell response to oxidative stress, and apoptosis. Pathways from the Kyoto Encyclopedia of Genes and Genomes (KEGG) related to the immune system response, inflammation and carcinogenesis were significantly upregulated.
Overall, our findings suggest that though LNP-based nanoparticles are valuable tools in medicine, some levels of toxicity can be attributed to their interaction with biological systems. Our findings will aid the evaluation of potential risks associated with LNPs use such as oxidative stress, increased immune and inflammatory responses, reduced cell metabolic activity
Utilization of Egg Quality Biomarkers and Probiotics for the Improvement of Eastern Oyster (Crassostrea virginica) Larviculture
No full textShellfish aquaculture is a growing industry in the U.S., with the eastern oyster (Crassostrea virginica) being one of the most economically important cultured species. However, seed supply is a limitation to the expansion of oyster aquaculture, as hatcheries often experience high mortality rates. Thus, there is a need to understand egg quality characteristics and improve hatchery production methods. This thesis assessed egg quality biomarkers and the effects of probiotics on eastern oyster larviculture. Results indicate that saturated fatty acids, particularly palmitic acid, are elevated in good-quality eggs and may act as biomarkers for egg quality. Furthermore, supplementing Bacillus probiotics to rearing systems improved larval survival and significantly reduced relative abundances of Vibrio. Overall, this work identified fatty acid profiles of good-quality eggs to inform which diets may be effective for broodstock conditioning, as well as demonstrated the benefits of probiotics for hatchery-reared eastern oyster larvae
Prognostic Health Management and Additive Manufacturing Quality Analysis of Cables
No full textElectrical systems regarding the transmittance of signals and data are under the constant threat of wear and tear. Many machines and systems that use cables to transfer signals and data are often used right up until failure before anything is done in terms of maintenance or installing preventative measures against failure. The research conducted in this thesis is a twofold, first doing extensive research into the identification and modeling of coaxial cable damage from accelerated damage testing and constructing preventative measures to stop electrocardiogram cables from experiencing environmental damage.
Prognostic health management (PHM) techniques are vital to understanding when a system is in need of maintenance as PHM can predict when the system is no longer functioning at a satisfactory level. There are three different methods conducted in this research to identify the damage being accrued to a coaxial cable using both standard laboratory equipment such as waveform generators and oscilloscopes as well as more specialized equipment such as a vector network analyzer for more detailed data.
Electrocardiogram (ECG) cables, which are critical for patient monitoring systems, undergo rigorous use which threatens the integrity and durability under various operational conditions. There is also the issue of additional cables, tubes, and other leads becoming entangled resulting in operational difficulties. The second chapter follows the development of a retractable cable housing specifically for a five-lead ECG cable using additive manufacturing methods to create the protective housing. Additionally, additively manufactured traces on specialized conductive printing platforms was proposed as a replacement to the standard wiring to decrease the profile of cable housing unit