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Microtubule Supported Trafficking of Synaptic Vesicle Precursors and Recycling Synaptic Vesicles
Get PDFSynaptic Vesicles are critical components for synaptic communication in the nervous system. The proteins associated with synaptic vesicles that enable their functionality must be continuously produced, transported to necessary locations, and then eventually removed for degradation to ensure healthy function throughout the lifetime of the neuron. The microtubule cytoskeleton has long been known to support motion of many components within the cell, and filamentary actin has been shown to support local motion of synaptic vesicles between presynapses in an activity dependent manner. However, questions remained as to the level of microtubule-based synaptic vesicle motion.
This dissertation presents results showing the mechanistic effects of the microtubule cytoskeleton on axonal cargo, as microtubule ends must be navigated by synaptic vesicle precursors delivering vital synaptic vesicle proteins to the presynapse. Further, our results show that synaptic vesicles also utilize the microtubule cytoskeleton. This microtubule supported motion allows for directional differences in motion due to the microtubule polarization within the axon. Directional differences are observed near functioning presynapses, as recently recycled vesicles are less likely to be captured by a presynapse when moving at higher speeds towards the cell body. A model of motion including differential capture probability among vesicles supported by different cytoskeletal networks is laid out and shown to support a net retrograde flux that supports healthy turnover of synaptic vesicle proteins.
Chapter 2 provides background information on the biological elements and concepts underlying my research. This presents essential topics needed to understand what was studied, the results of the experiments, and the context of the results within the larger landscape of research. Chapter 3 then sets the stage with open questions in the field upon which my research sheds new light. Chapter 4 explains the methods and materials used to experimentally study synaptic vesicles and synaptic vesicle precursors. This chapter will build on the background information provided with specific information about how these elements are studied. Chapter 5 contains the experimental results and computational models based on those results. Finally, Chapter 6 contains discussion of the results, as well as an extended discussion of their meaning within the larger context of the field, along with further questions yet to be answered
CTE Leadership: An examination of leadership competencies, challenges, and professional development needs of administrators
No full textThe goal of this research study was to identify the leadership skills of CTE administrators, the challenges of CTE administrators, and the areas where professional development were needed. The purpose of the study was to determine if a relationship existed among CTE administrators’ perceived level of leadership competencies, perceived challenges as a CTE administrator, areas of needed professional development, and if any relationships existed among specific demographics (gender, age, current leadership position, highest degree, school location) of CTE administrators and areas of professional development needs as indicated.
Data was analyzed using Descriptive Statistics, One-Way Analysis of Variance (ANOVA), and One-Sample Chi Square Tests. Electronic surveys were distributed via email to approximately 200 acting CTE administrators in the state of Alabama; 85 responded, however, 28 responses were omitted for the analysis due to incomplete survey (N = 57). Most respondents were Caucasian (67%), male (51%), with an age range of 41-50 years (39%), and have been a CTE administrator for 0-5 years (37%). There were 40% of respondents with a Master’s degree, 25% with an Education Specialist degree, and 33% with a doctorate degree. The majority of respondents (54%) indicated they had a background in CTE prior to being appointed as a CTE administrator.
There were significant differences found between administrators from a CTE background and administrators from a non-CTE background on perceived leadership competencies and on perceived challenges. There was a statistically significant difference between males and females on leadership competencies with males indicating a higher level of competency. Additionally, there were significant differences between administrators from a CTE background and a non-CTE background on areas of professional development that were identified as a need.
As a result of this study, additional research is needed to determine why males report a higher level of competency in leadership skills than females. Additional analysis should be conducted to explore the qualitative answers to the most important leadership skills identified by CTE administrators and the top indicated challenges a CTE administrator encounters. Similar studies should also be conducted in other states
The Prevalence of Low-Level Exertional Rhabdomyolysis and Muscle Damage During Military Field Training Exercises
No full textExertional rhabdomyolysis (ER) is a condition characterized by skeletal muscle breakdown due to strenuous physical exertion. ER has a higher prevalence in populations undergoing rigorous training, such as military personnel. ER incidence rates in military settings are up to 20 times that of civilian populations. Despite this prevalence, many ER cases remain undiagnosed or underreported particularly among Reserve Officer Training Corps (ROTC) cadets. This research aims to explore physiological and psychological changes occurring during a two-to-three-day ROTC field training exercise (FTX), focusing on biomarkers such as creatine kinase and myoglobin, energy availability, hydration status, and training adaptations. The findings contribute to a deeper understanding of ER risk factors and recovery mechanisms in ROTC members.
The first portion of this project examined the effects of an ROTC FTX on cadet nutrition and energy balance. The results demonstrated that cadets often fail to consume sufficient nutrition to maintain energy balance, leading to short-term low energy availability. This suggests that strategic fueling strategies, improved ration compositions, and enhanced nutrition education are necessary to sustain both training performance and long-term health.
The second portion of this project explored the effects of an ROTC FTX on physical and psychological strain, measured through pain pressure threshold, mood, energy, and restfulness. The results demonstrated that cadets experienced a significant decline in mood, energy, and restfulness early in the FTX, particularly among Marines. Pain Pressure Thresholds (PPT) values correlated with fatigue and muscular strain, with novice cadets experiencing greater physiological stress. This suggests that recovery strategies should be tailored to branch-specific needs, experience level, and conditioning.
The third portion of this research evaluated the effects of a ROTC FTX on hydration markers, electrolyte balance, and metabolic biomarkers. The results demonstrated significant changes in hydration status and metabolic markers, though blood markers of renal function remained stable. This suggests that monitoring hydration and metabolic responses is crucial in training environments.
The final portion of this project brought together the three prior sections to evaluate the effects of an ROTC FTX on systemic stress, metabolic shifts, and muscular adaptations. The results demonstrated that cadets exhibited physiological changes in hydration status, metabolic markers, and pain tolerance. Higher body fat percentages and older age were correlated with greater metabolic fluctuations, and fitness levels appeared to buffer metabolic perturbations. These findings suggest that physiological responses to military training are transient, with adaptations primarily reflecting immediate physical demands rather than long-term alterations.
Collectively, this body of research provides insight into the physiological and psychological adaptations experienced by ROTC cadets during a FTX. The findings suggest that cadets generally adapt well to training demands, and that nutrition, hydration, recovery strategies, and individual variability play key roles in optimizing performance and minimizing risks
Design and Validation of Cable-Driven Robots for Human Rehabilitation and Assistance
No full textHuman and robot interaction is the key to improving the lives of many people around
the world through rehabilitation, simulation, and performance enhancement.
To improve rehabilitation initiatives and provide patients and doctors with the means
for episodic future thinking (EFT), implementation of virtual reality (VR) simulations and
the rendering of internal impedances in those simulations is key. While previous research
has explored external effects in these simulations (such as haptic interaction with a virtual
object), internal avatar changes remain an open question. Given that current devices only
generate external effects, it is extremely valuable to understand if those effects could be
interpreted as internal ones. To assess this, Ideveloped a novel robotic system (Stiffness
Emulation Robot, SER) and a new controller for an existing haptics glove (HaptX G1) and
conducted a binary discretion experiment which reveals that most people can differentiate
the two impedance types.
Alternatively, instead of providing simulation effects, robots can be used to increase
human performance by manipulating how one interacts with the world. An example of
this is in search-and-rescue litter carry groups, where long-distance carry of high-loads can
impose significant stress on human fingertips, leading to grip fatigue and eventual failure.
While there exists off-the-shelf means of alleviating this stress, a robotic device could provide
additional advantages such as enabling/disabling to remain unobtrusive when not in use – a
critical requirement in high-stakes environments. To achieve such performance, the Curling
Artificial Soft ExoskeleTon (CASET) was developed. An experiment where participants held
high loads to failure both with and without CASET revealed drastic performance increases,
both in carry time and grip fatigue reduction
Exploring U.S. Consumer Insights on Poultry Welfare and Labeling
No full textThe poultry industry has experienced significant growth, leading to increased scrutiny of poultry welfare and labeling practices. This study aims to assess consumer perceptions of broiler stunning methods which are directly related to poultry welfare during processing, animal welfare, and key labeling attributes influencing purchasing decisions in poultry meat products. Through an online survey, the first study evaluated consumer (n=986) knowledge and attitudes toward poultry stunning methods (Electrical vs Controlled Atmosphere stunning). The results show that 10% of respondents understood the concept of stunning, and 22% had a conceptual understanding of animal welfare. Despite growing awareness of animal welfare; food safety and price remain the primary concerns in poultry products. Consumers with higher knowledge (those who scored <10 on knowledge assessment) of poultry processing represented 18% of respondents, highlighting a gap in public understanding of animal welfare practices. A follow-up survey, Choice Based Conjoint study, with 630 U.S. chicken consumers was conducted to examine the impact of labeling attributes on purchasing behavior for raw and ready-to-eat (RTE) chicken. The findings indicate that price was the most influential factor (RAW=52.3%; RTE=57.2%), followed by certified labels (RAW=28.9%; RTE=28.2%) and claims (RAW=18.7%; RTE=14.7%). Across categories, the “$2.97/lb.,” “3.47/lb.,” “USDA Organic,” label and “NAE” and “NAHS” were preferred. Additionally, consumers expressed higher interest in welfare for RAW than RTE products. These results reveal that while consumer behaviors may vary for products within the same category, pricing remains a priority along with simple packaging cues. Consumer knowledge and familiarity remains limited about the implications of animal welfare and available certifications in the market. The findings from both studies demonstrate that price is the dominant factor driving purchasing behavior in poultry meat products
Factors Associated with Successful United Nations Peacekeeping Missions
Get PDFPeacekeeping is an essential component of the United Nations’ contributions to fulfill its core mission of maintaining international peace and security. UN peacekeeping missions (PKMs) are Security Council (SC) approved interventions in areas of conflict. The intensity of these missions ranges from observation to enforcement. Much has been written about the success or failure of these missions, but quantification of success and examination of the factors associated with success are missing from the literature. This research examines 69 PKMs between 1945 and 2013 in an attempt to identify characteristics of the mission, known at the time of the Security Council vote on the missions, that are associated with the success of the missions. The data collected for the study include information on the SC concerns about the conflict, the mandate purposes, the authorized UN personnel, the mission level of intensity, the global region of the conflict, the time era, and other details of the mission. This information was statistically analyzed to identify factors that are associated with success and also with secondary outcomes of UN personnel fatalities and the duration of the PKM. Additional analyses were performed that included factors known during the PKM such as mandate expansion, timeline extension, and the actual deployed UN personnel during the course of the PKM.
The PKMs were successful in 30 (43%) of the 69 missions. The success rate has declined over time (61% prior to 1990 to 31% after 2000), is lower in enforcement missions (26%), and missions that have a purpose of humanitarian relief (31%). If the mandate was expanded during the course of the PKM, then the success rate is lower (36%). As the duration of the PKM increases, the rate of success decreases (PKMs with a duration longer than 10 years have a success rate of 17%). This research also found that the PKMs have evolved over time: they now have more mandate components, more enforcement missions, and more UN personnel.
Factors associated with an increased number of UN personnel fatalities include the recent time era, enforcement missions, the number of UN deployed personnel, and the extended duration of the mission. Factors associated with an increase in duration include the regions of the Middle East and Europe, a purpose of maintaining a ceasefire, and expansion of the mandate.
Successful PKMs are a major challenge for the Security Council. As the SC considers a new PKM, their understanding of the factors associated with success, fatalities, and duration may assist them in evaluating the risks of a mission and in allocating the necessary resources to increase the probability of success while minimizing fatalities and the mission duration
Project-Based Learning, Transdisciplinary Literacy, Equity Lens - A Mixed Method Study Facilitated to Examine Teacher Identities and Student Impact
Get PDFThe study reported a mixed-methods research of transdisciplinary literacy (TDL) within a kindergarten through 3rd-grade project-based learning (PBL) unit design. This study has important implications as it analyzed how elementary teachers’ identities impacted how they approached text selection, evaluated PBL lessons through a transdisciplinary lens, and shifted their teaching strategies within a Community of Practice (CoP). Through a convergent parallel mixed-methods design, the researcher provided evidence to support how a transdisciplinary approach informed instructional knowledge and the development of innovative practices as twenty teachers created rigorous PBL units that engaged students to generate authentic products. The quantitative portion of the research involved pre- and post-survey comparisons from teachers within the CoP and an examination of benchmark data from student English Language Arts/Reading and Math percentile achievement scores from the Measurement of Academic Progress (MAP) testing. The student population consisted of up to 73 male and female children, kindergarten through third grade, who attended a Title 1 school in rural Southwest Georgia. In the qualitative portion of this study, the researcher conducted an inductive analysis of data gathered from twenty certified elementary teachers from the same school. Data included field notes, observations, and interviews about how learners of all abilities interacted and engaged with texts, and how their achievement was shaped by instruction focused on transdisciplinary literacy and PBL frameworks. Results could inform future studies about the role of TDL as teachers created PBL lessons with a focus on recognizing how learners need different approaches, resources, or supports. Moreover, this study furthered the quest for educators to select texts responsive to all learners within the U.S. educational systems
Resisting Resistance: Development of Nanoparticle-mediated Delivery Systems to Explore RNA Interference as a Solution to Biological Resistance
No full textBiological resistance to conventional pesticides and antifungals presents a significant challenge in agriculture and healthcare, necessitating the development of alternative control strategies. RNA interference (RNAi) offers a highly specific and environmentally sustainable approach to managing resistance, but its widespread application is hindered by the lack of efficient RNA delivery methods. This dissertation explores nanoparticle-mediated delivery systems for double-stranded RNA (dsRNA) to enhance RNAi efficiency in both fungal and insect models.
While RNAi is a promising tool for gene regulation, the clear structural and physiological differences between yeast and insects necessitate distinct delivery approaches. For delivery in yeast, we developed the first nanoparticle-mediated photoporation system focused on delivery into fungal cells. This required the meticulous optimization of laser power, wavelength, irradiation time, and several nanoparticle characteristics to maximize RNA uptake while maintaining cell viability. All optimizations were done in Saccharomyces cerevisiae before moving on to gene silencing in the clinically-relevant pathogen, Candida albicans. In contrast, we investigated branched amphiphilic peptide nanocapsules (BAPCs), a biologically-derived peptide-based nanoparticle, for RNAi delivery in the fall armyworm (Spodoptera frugiperda), a major agricultural pest, where nanoparticle concentration and silencing efficiency were studied. Additionally, cellular uptake and trafficking mechanisms were studied using Sf9 cells. Gene silencing efficacy was evaluated in both models using RT-qPCR.
Our findings demonstrate that photoporation successfully facilitates the intracellular delivery of various molecules in yeast, marking the first application of this technique in fungal systems. Additionally, fall armyworms readily consume BAPCs complexed with dsRNA, resulting in effective gene silencing. Evidence suggests that transcytosis plays a role in nanoparticle transport from the gut to systemic tissues, highlighting a potential mechanism for RNAi-based pest control.
This work enhances the field of drug delivery through the development and optimization of of new delivery methodologies and providing insights into mechanisms surrounding nanoparticle-mediated RNA delivery in fungal and insect systems. By bridging the gap between laboratory research and field applications, these nanoparticle-mediated RNAi delivery strategies provide a foundation for novel RNA-based fungicides and insecticides as sustainable alternatives to current chemical treatments
Career Pathways of Agriculture Students: An Introspective Look Through a 40-Year Lens
Get PDFEscalating workforce demands, rapid technological advancements, and the rise of niche markets have significantly impacted agricultural career pathways and post-secondary educational opportunities, increasing the importance of advanced degrees and specialized certifications. Over the past four decades, the skills and education required for agricultural professionals have transformed, with substantial growth in demand for highly skilled individuals to fill both traditional and new positions, including within the expanding Agricultural Leadership, Education, and Communications field. The industry also needs a diverse and highly skilled workforce to navigate modern agriculture's complexities. A comprehensive examination of the agricultural industry explored existing and emergent career paths, analyzed historical trends in agricultural employment, and identified new career trajectories resulting from workforce expansion, talent retention, and various state and national initiatives emphasizing the need for a highly skilled and educated workforce. The skills and competencies required for these evolving roles were examined, considering the impact of technological advancements and the resulting demand for specialized knowledge. The alignment of existing educational programs with current and projected workforce needs was assessed, identifying potential gaps and areas for improvement.
Based on these findings, I recommend unifying the disconnected Agricultural Leadership, Education, and Communications program under a single department within the College of Agriculture. The group housed within the College of Education should transition to the College of Agriculture, joining the other existing program areas (ag communications, ag leadership, and agricultural science) under unified leadership. This consolidation reflects this field's position as an applied field of agriculture and mirrors every aspirational or peer program, both nationally and internationally. While teacher training is one aspect, it's a small part of agriculture's broader social and behavioral sciences. Auburn University should look to peer and aspirational Land-Grant institutions for models and best practices to serve its mission of improving agriculture and Alabama. A limited perspective of the administrative organization is hindering progress and undermining efforts to retain Alabamians in the state's most valuable workforce, the agricultural workforce. I recommend that Auburn University adheres to established CIP codes, using 01.0801 for ALEC teacher/extension agent aspects and 01.0899 for non-formal aspects (Ag Leadership/Ag Science). This work aimed to understand how educational institutions can effectively prepare students for diverse agricultural career opportunities, contributing to a robust and adaptable workforce that meets 21st-century challenges
Assessing the Transfer of Learning: A Qualitative Case Study on the Acceptance of Knowledge from a Military Faculty Development Center
No full textThis qualitative case study explored training transfer among Military Instructors at the Marine Corps Faculty Development School, emphasizing training acceptance versus knowledge acquisition through a constructivist lens. Using semi-structured interviews conducted immediately post-training and six weeks later, the study examined how instructors perceived, accepted, and integrated training into their instructional practice (Merriam, 1998; Yin, 2018). Three concepts guided the analysis: training acceptance—instructors’ perceptions of relevance and applicability (Burke & Hutchins, 2007; Ford et al., 2017); knowledge acquisition—the absorption of content and strategies (Baldwin & Ford, 1988; Illeris, 2009); and training material utilization—how materials were applied or adapted in practice (Biech, 2017; Schmidt, 2014). Data from interviews, observations, and curriculum reviews provided a rich understanding of learning transfer, reinforcing the value of constructivist principles in military faculty development and the broader goal of enhancing instructional effectiveness (Blume et al., 2009; Salas et al., 2012)