Physical Sciences and Mathematics Commons^™

Exploring Soil Microbial Dynamics In Southern Appalachian Forests: A Systems Biology Approach To Prescribed Fire Impacts, Saad Abd Ar Rafie

Doctoral Dissertations

Prescribed fires in Southern Appalachian forests are vital in ecosystem management and wildfire risk mitigation. However, understanding the intricate dynamics between these fires, soil microbial communities, and overall ecosystem health remains challenging. This dissertation addresses this knowledge gap by exploring selected aspects of this complex relationship across three interconnected chapters.

The first chapter investigates the immediate effects of prescribed fires on soil microbial communities. It reveals subtle shifts in porewater chemistry and significant increases in microbial species richness. These findings offer valuable insights into the interplay between soil properties and microbial responses during the early stages following a prescribed fire. …

Integration Of Raman Spectroscopy And Python-Based Data Analysis For Advancing Neurobiological Research, Natalie E. Dunn

Doctoral Dissertations

The field of Raman spectroscopy continues to expand into biological applications due to its usefulness as a non-invasive technique that can be utilized qualitatively and quantitatively. However, the inherent weakness of Raman scattering leads to the need for each collected spectra to undergo a preprocessing step to remove noise, background drift, and cosmic rays. Biological research in particular needs large datasets due to the increased variability in samples. As datasets grow, the need to perform preprocessing on each individual spectra becomes daunting. Often, these steps are done by hand with the help of specialized software programs. Preprocessing can be accelerated …

The Impacts Of Tilled-In Biodegradable Plastic Mulch On Soil Microbial Communities, Corissa L. Martin

Masters Theses

Plastics mulch films are used in agriculture to help increase crop production by regulating soil water retention and soil temperature while also preventing weed growth. Despite these benefits, plastic mulches have led to higher levels of microplastic pollution as weathering occurs. In response to this issue, biodegradable plastic mulches (BDMs) have been introduced to help reduce plastic pollution as they are designed to be tilled into soil after each growing season to continue degradation. Degradation of these mulch films is dependent on climate and, in some areas, complete degradation can take years. Since some biodegradable plastic mulches are made of …

Do Microplastics, Vibrio Bacteria, And Warming Water Temperatures Cause Disease In The Northern Star Coral, Astrangia Poculata?, Heather Leigh Sheffey

OES Theses and Dissertations

As marine plastic pollution increases, it becomes imperative to study the effects of microplastics on marine fauna. Marine plastic debris is a vector for disease to marine invertebrates (Lamb et al., 2018; Rotjan et al., 2019). In this context, studies have shown Astrangia poculata will consume microplastics as they do their normal food (Allen et al, 2017; Rotjan et al., 2019). Further, with temperatures increasing worldwide, there is a concern the virulence of disease-causing bacteria will increase (Vezzulli et al., 2015). In a series of manipulative laboratory experiments, this study quantified changes in respiration rates and visual health of Astrangia …

Structural Insights Into The Cl-Par-4 Protein: Ionic Requirements, Conformational Transitions, And Interaction With Cisplatin, Krishna Kumar Raut

Chemistry & Biochemistry Theses & Dissertations

Cancer continues to be the leading global cause of death, with challenges in early diagnosis, drug resistance, non-specific drug targeting, and cancer recurrence and metastasis posing formidable obstacles in cancer therapy. In this context, Prostate Apoptosis Response-4 (Par-4), a pro-apoptotic tumor suppressor protein, emerged as a promising therapeutic target due to its ability to selectively induce apoptosis in cancer cells, thereby minimizing the drug-associated adverse effects. However, a comprehensive understanding of the structural features of Par-4, specifically the caspase-cleaved fragment (cl-Par-4), is crucial for therapeutic advancements.

This dissertation investigated the effects of various ions, both monovalent and divalent, on the …

Growth Of Purple Sulfur Bacteria Allochromatium Vinosum On Solid Phase Metal Sulfides As Sulfur And Electron Sources, Hugo Alarcon

Open Access Theses & Dissertations

Purple sulfur bacteria (PSB) are photosynthetic microorganisms known for their vital roles in geochemical cycles, especially the sulfur cycle, within anoxic photic environments. PSB are also key contributors to the nitrogen, carbon, and oxygen cycles. This study focuses on the autotrophic growth of Allochromatium vinosum, a model strain of PSB, that utilize solid-phase metal sulfides (MS) as both sulfur and electron donors. Through characterizing the growth profiles of A. vinosum on pyrite (FeS2), nickel sulfide (NiS), and iron monosulfide (FeS) nanoparticles, respectively, and investigating the bacteria-MS interaction mechanisms, this work expands our current knowledge of the metabolic capabilities and flexibility …

Considerations For The Use Of Mycorrhizal Fungi Inoculants In Coal Mine Reclamation And Reforestation In Appalachia: A Guide Of Best Practices And Management Recommendations, Cole Hansen Reistrup

Master's Projects and Capstones

Nearly all terrestrial plants form symbiotic relationships with mycorrhizal fungi. These beneficial soil microbes support plant health by increasing plants’ access to nutrients and water, protecting them from pathogens, improving soil properties, and more. A challenge to restoring forests on coal mined land in Appalachia is that mine soils are often degraded in a number of ways, including lacking mycorrhizal fungi, which makes mine soils difficult for trees to grow upon. Substantial improvements to coal mine reforestation success have been made since the development of the Forestry Reclamation Approach in 2005 that provides guidelines for how to create a suitable …

The Future Is Now In Twisted Coil Polymer Actuators (Tcpa), Ryan Ronquillo

Electronic Theses and Dissertations

This thesis aimed to fabricate and test twisted coiled polymer actuators (TCPA) to understand the mechanical and thermal aspects of this artificial muscle fiber. The purpose of this thesis was to find a linear relationship using the LVDT sensor, fabricating TCPA fibers, and interpreting the data. The project tested whether nylon/polymer could be used as a better artificial muscle fiber.

This research accomplished three goals: (1) designing and fabricating a system capable of creating supercoiled muscle fibers consistently, (2) calibrating the Linear Variable Differential Transformer (LVDT) and Core, and (3) analyzing/interpreting the data of the Twisted Coiled Polymer Actuators (TCPA) …

Desert Spring Prokaryotes And Benthic Macroinvertebrates: Geological And Ecological Controls, Ariel D. Friel

UNLV Theses, Dissertations, Professional Papers, and Capstones

Desert springs are aquatic oases, being considered among the most diverse and imperiled ecosystems on Earth. Despite the ecological significance and threatened status of desert springs, few studies have surveyed the microorganisms in these systems or their interactions with other community members. The primary goal of this dissertation was to describe the major controls influencing the community ecology of prokaryotic and BMI communities in cold- and moderate-temperature desert springs of the southern hydrographic Great Basin. Chapter 1 provides a broad overview of spring ecosystems and of each chapter included in this dissertation. Chapter 2 documents the first-ever, regional-scale survey of …

Psf Sampling In Fluorescence Image Deconvolution, Eric A. Inman

Master's Theses

All microscope imaging is largely affected by inherent resolution limitations because of out-of-focus light and diffraction effects. The traditional approach to restoring the image resolution is to use a deconvolution algorithm to “invert” the effect of convolving the volume with the point spread function. However, these algorithms fall short in several areas such as noise amplification and stopping criterion. In this paper, we try to reconstruct an explicit volumetric representation of the fluorescence density in the sample and fit a neural network to the target z-stack to properly minimize a reconstruction cost function for an optimal result. Additionally, we do …

Assessing Ecotoxicity Of Surface Water And Sediment In The Little Scioto River, Leah Suzanne Morgan

Theses, Dissertations and Capstones

Aquatic toxicology evaluates the impact of pollution on freshwater and marine biota. Polycyclic aromatic hydrocarbons (PAHs) are one class of chemicals prevalent in the environment that impair aquatic organisms. This study examined the effect of contaminated surface water and sediments from a former wood treatment facility on four aquatic species: Pimephales promelas (fathead minnow), Ceriodaphnia dubia (water flea), Chironomus dilutus (midge), and Daphnia magna (water flea). The findings showed that sediment contamination had no significant effect on survival and growth of C. dilutus or on survival of D. magna. Surface water contamination began to have a significant effect on …

Soil And Compost Tea: A New Restoration Technique?, Carol E. Day

Master's Theses and Doctoral Dissertations

Historically, prairie restorations have lacked the plant diversity seen in remnant prairies. Most restoration practices focus on reestablishing the plant community but overlook the soil microbial community even though microbes are critical to habitat functioning. Developing techniques that increase soil microbes in prairie restorations is critical to ensuring diverse restored habitats. We compared how microbial communities differed between remnant and restored prairie sites. We also investigated if soil and compost teas could be used to reintroduce microbes to restored prairie soil and if the teas affected native plant establishment. We found significant differences in the levels of bacterial taxa between …

Laboratory Practices And Antimicrobial Resistance In A Florida Hospital, Crispina Marie Sy-Trias

Walden Dissertations and Doctoral Studies

Antibiotic resistance is a health threat affecting millions of Americans. Microorganisms develop resistance to antibiotics, rendering them useless for treating infections. The purpose of this quantitative study was to assess the associations between sample processing time and antibiotic resistance and is based on the health belief model. A retrospective specimen tracking activity of data from November 2019 to November 2020 was obtained by random sampling of 246 bacterial cultures. One hundred ninety-six (80%) samples were processed on time, and 50 (20%) were delayed; 167 (68%) samples were determined to have the presence of antimicrobial resistance (AMR), and 79 (32%) with …

Changes And Relationships Of Soil Aluminum, Organic Matter, And Hydrogen Ion Concentration With Rye Cover Crop, Arron Wilder

Cal Poly Humboldt theses and projects

Soil acidity is a common agricultural problem worldwide, as approximately 50% of all potentially arable soils are affected by pH limitations. At soil pH 3+) is considered to be the chemical form of aluminum in acid soil that hinders plant growth the most. Potentially, soil organic matter (SOM) can ameliorate the toxic effects of Al³⁺ on plants and microbes by binding with Al³⁺, thus preventing Al³⁺ (and other species of aluminum) from interacting in the rhizosphere. Increasing SOM also increases soil health indicators (i.e., microbial activity, soil water holding capacity, aggregate stability, porosity, etc.) while the …

Detection And Diagnosis Of Bacterial Pathogens In Blood And Urine Using Laser-Induced Breakdown Spectroscopy, Emma J.M. Blanchette

Electronic Theses and Dissertations

The aim of this thesis is to expand on and improve the existing techniques used for detecting and identifying bacterial pathogens in clinical specimens with laser-induced breakdown spectroscopy (LIBS). Specifically, the existing experimental procedures, including bacterial sample preparation and data acquisition, as well as the data analysis with chemometric algorithms were investigated. Substantial reductions in LIBS background signal were achieved by implementing rigorous cleaning steps and the introduction of the use of ultrapure water. Following this, a database of LIBS spectra was acquired from specimens of E. coli, S. aureus, E. cloacae, M. smegmatis, and P. …