Undergraduate Research Option Theses

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Undergraduate Research Option Theses

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https://hdl.handle.net/1853/71011

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Undergraduate Research Opportunities Program

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Now showing 1 - 10 of 855

Assessing the conformation shift of transfer RNA phenylalanine in the presence of iron(II) and magnesium(II)

(Georgia Institute of Technology, 2013-05-08) Hoskyns, Spencer ; Chemistry and Biochemistry

The combining of the small subunit and large subunit (LSU) of the ribosome activates the synthesis and extension of a polypeptide through peptide bond formation at the peptidyl transferase center (PTC). This complex incorporates transfer RNA (tRNA) for the transfer of an amino acid to a growing polypeptide chain. Core sequences of ribosomal RNA (rRNA) are coordinated by magnesium cations and quasi-encapsulating ribosomal proteins. Superimposition of LSU crystal structures of many prokaryotic and archaeal species reveals a structurally conserved, magnesium rich core near the site of peptidyl transfer2. The structural change of tRNA in the presence of magnesium(II) could have serious implications for its interactivity with the PTC for peptidyl transfer. Circular dichroism spectroscopy was utilized to determine the structural change associated with the presence of magnesium(II).
Particle Image Velocimetry of Collapsing Toroidal Droplets

(Georgia Institute of Technology, 2015-08-18) Berger, Eric M. ; Kennedy, T. A. Brian ; Fernandez-Nieves, Alberto ; Greco, Edwin ; Physics

The goal of this study is to explore the mechanism by which unstable toroidal droplets collapse inwardly. As such, particle image velocimetry methods will be employed in obtaining an experimental picture of the velocity field inside of unstable toroidal droplets as they collapse. The inward collapse exhibited by unstable toroidal droplets is unique to the geometry of the torus and is therefore physically interesting. There is currently not an available experimental picture of this collapse, so this study will attempt to fill that void. Ultimately the results of this study will be compared against the currently accessible theoretical pictures of collapsing toroidal droplets, leading to further refinements in the field.
Identifying the potential effect of zolmitriptan on the 1b pathway of Golgi tendon organs in regulating intermuscular inhibition in the extremities to find a link in the mechanism of spasticity

(Georgia Institute of Technology, 2023-01-18) Davis, Adam Eugene ; Nichols, T. Richard ; Neuroscience (Undergrad)

The deep dorsal horn (DDH) of the spinal cord is a major integration center for receiving a variety of neural projections from the brainstem as well as a variety of afferent inputs from muscle spindles and Golgi tendon organs (GTOs) in the muscles. Following spinal cord injury (SCI) to the DDH, an overall loss of serotonergic input from the brainstem is observed, for which there is evidence to suggest that this may play a role in inhibiting the activity of bursting interneurons in the DDH, possibly leading to uncontrolled motoneuron activity, hyperreflexia. GTOs primarily supply the force feedback network (FBB), which also receives supraspinal input through the DDH, likely also affected by its loss in SCI. The purpose of this current study is to investigate if FBB function changes, with or without SCI, after the administration of a specific serotonin reuptake inhibitor (SSRI), zolmitriptan, which inhibits the activity of the bursting interneurons. FBB function was determined primarily as inhibitory signals from the flexor hallucis longus (FHL) onto the gastrocnemius (GAS), the muscle tensions compared after being stretched individually and pairwise, with some data from rectus femoris (RF) onto GAS. The autogenic stretch reflex was analyzed only in GAS. Animals with an intact spinal cord (n=1) and with a lateral hemisection (n=2) were used to compare the changes in reflexes following zolmitriptan administration. Data was variable across the subjects with no clear effect on the autogenic stretch reflex in GAS. The more stable lateral hemisection subject revealed that zolmitriptan largely and consistently increased inhibition from FHL onto GAS from a miniscule baseline, suggesting connectivity between the GTO circuit and the bursting interneurons of the DDH. Notably in the intact spinal cord animal, there was an immediate and complete correction of oscillations in the baseline tension of all muscles after drug administration, treating a symptom of hyperreflexia. These results suggest a connection between the two systems or a more significant role of this particular serotonin receptor on GTO circuit and the DDH. More studies may provide a deeper understanding of this network and these findings.
Using First Order Inductive Learning as an Alternative to a Simulator in a Game Artificial Intelligence

(Georgia Institute of Technology, 2009-05-04) Long, Kathryn Anna ; Computer Science

Currently many game artificial intelligences attempt to determine their next moves by using a simulator to predict the effect of actions in the world. However, writing such a simulator is time-consuming, and the simulator must be changed substantially whenever a detail in the game design is modified. As such, this research project set out to determine if a version of the first order inductive learning algorithm could be used to learn rules that could then be used in place of a simulator. By eliminating the need to write a simulator for each game by hand, the entire Darmok 2 project could more easily adapt to additional real-time strategy games. Over time, Darmok 2 would also be able to provide better competition for human players by training the artificial intelligences to play against the style of a specific player. Most importantly, Darmok 2 might also be able to create a general solution for creating game artificial intelligences, which could save game development companies a substantial amount of money, time, and effort.
The Role of Noise-Induced Excitable Dynamics of Rho Family GTPases in the Regulation of Actin Cytoskeleton

(Georgia Institute of Technology, 2021-12) Rahman, Farhan S. ; Tsygankov, Denis ; Hladyshau, Siarhei ; Biomedical Engineering (Joint GT/Emory Department)

Rho GTPases, a family of signaling proteins, play a pivotal role by acting as molecular switches to regulate F-actin cytoskeletal and cell adhesion. Recent studies have shown that reaction-diffusion (RD) models have the ability to exhibit a wide variety of characteristic patterns of wave propagations of Rho GTPases. This study uses computational modeling to investigate a particular dynamic behavior directly relevant to the observed protrusive activity of motile cells: a single decaying traveling wave of actin polymerization. The model is conducted in a 2D cell of an arbitrarily complex shape. It reveals that the inhibitor decay rate controls the transition from reflecting waves to a single decaying wave and helps to avoid the formation of spiral waves. For noise, we observe that it controls the propagation of wavefronts, such that higher amplitudes of noise induce a greater number of waves. Additionally, the model distinguishes that noise induces waves at different time points. These findings serve as a framework for further comprehensive representation of actin polymerization during cellular morphogenesis.
Influence of Social Intention on Switch Cost in Task-Switching Paradigms

(Georgia Institute of Technology, 2020-12) Barrett, Jacquelyn Marie ; Schumacher, Eric H. ; Verhaeghen, Paul ; Psychology

Humans have built a society based upon elaborate social interactions. We have processes that enable us to interact with each other and switch between tasks. Humans often multitask especially in a social context, such as talking while working on a project, listening to someone while driving, or switching between conversations with different people. One of these processes that aids in this interaction is the intentional stance. The intentional stance is the tendency humans have to view other’s actions as driven by their own mental states, beliefs, and intentions. In this experiment, it is examined whether or not social cognition, such as inferring the beliefs or intentions of others, behaves like other cognitively dominant tasks. Cognitively dominant tasks are automatic processes that are elicited with minimal to no effort, such as reading. A task switching paradigm was used among two groups, social and non-social, where tasks in the social group invoke the intentional stance and tasks in the non-social group do not. Switch cost, the increase in reaction time when switching between tasks, may increase when switching from a hard task to an easier task. This is due to the amount of inhibition initially placed on the easier stimuli in order to attend to the cued, more difficult stimulus until the more readily available stimulus has become relevant again Based on previous research, it is believed that switching from a non-social to a social task will result in a greater switch cost due to the amount of effort needed to overcome inhibition initially placed on the more readily available stimuli, or the social stimuli. These findings would support the hypothesis that social cognitive process behave similarly to other cognitively dominant processes.
Encoding Differences in Aging Adults can Explain Associative Memory Deficits

(Georgia Institute of Technology, 2020-05) McClelland, Lauren ; Duarte, Audrey ; Brown, Thackery ; Holder, Mary ; Psychology

The relationship between aging and associative memory decline has been well-established in literature, however there is no clear reasoning for this decline. Recent functional magnetic resonance imaging (fMRI) studies have shown that aging adults show decreased neural specificity across the cortex, now commonly termed dedifferentiation. The current research attempts to find a relationship between increased dedifferentiation with age and their resulting decreases in associative memory performance. By utilizing multi-voxel pattern analysis (MVPA) classifiers, the level of neural distinctiveness of the variably aged adults can be quantified and compared to associative memory performance. We found that neural distinctiveness was decreased with age as well as retrieval of increasing levels of specificity of associate items. This suggests that the associative memory decline in older adults can be explained by a decrease in neural specificity for the specifics of associate items during encoding.
Finite Element Simulations of Comprehensive Mitral Valve Model

(Georgia Institute of Technology, 2015-01-27) Pena, Marcel ; Yoganathan, Ajit ; Behravesh, Essy ; Toma, Milan ; Biomedical Engineering (Joint GT/Emory Department)

Mitral regurgitation (MR) is an increasingly prevalent disorder of the heart in which the mitral valve (MV) does not close properly causing blood to flow backward (leak) into the upper heart chamber when the left lower heart chamber contracts. MR is the most common type of heart valve insufficiency, often requiring open-heart surgical repair. After age 55, some degree of MR is found in almost 20% of men and women. MV repair is considered superior to mitral valve replacement, and there are many surgical techniques utilized to address differing pathologies. One approach to assess the effects of pathology and proposed surgical repair is to utilize a computational model, in which pathologic or surgical alterations can be assessed systematically. However, current models are limited by assumptions related to geometry and material properties and importantly, none have been validated with detailed experimental data. In the present work, an advanced fluid-structure interaction (FSI) model of the MV system is utilized without the limitation of geometry and material properties. This model allows analysis of the valve in the normal, diseased, or repaired states.
Efficiency of Spearcon-Enhanced Navigation of One Dimensional Electronic Menus

(Georgia Institute of Technology, 2008-05) Palladino, Dianne K. ; Psychology

This study simulated and compared cell phone contact book menu navigation using combinations of both auditory (text-to-speech and spearcons) and visual cues. A total of 127 undergraduates participated in a study that required using one of five conditions of alphabetically listed menu cues to find a target name. Participants using visual cues (either alone or combined with auditory cues) outperformed those using only auditory cues. Performance was not found to be significantly different among the three auditory only conditions. When combined with visual cues, spearcons improved navigational efficiency more than both text-to-speech cues and menus using no sound, and provided evidence for the ability of sound to enhance visual menus. Research results provide evidence applicable to efficient auditory menu creation.
Discovery of Monoclonal Antibodies for Diagnostics and Therapies Using Conjugate Virus-like Particle Vaccines

(Georgia Institute of Technology, 2021-05) Schroeder, Michelle ; Finn, M. G. ; Thomas, Susan ; Chemistry and Biochemistry

Monoclonal antibodies (mAbs) are highly specific antigen binding proteins that are used as biological reagents, therapeutics, and in rapid diagnostics. While mAbs have extensive potential applications, their means production for small molecules and conformationally specific peptides is difficult. Here, we use a method of mAb production in which we pair conjugate virus-like particle (VLP) vaccine with hybridoma technology to produce high-affinity mAbs against three classes of molecules 1) fentanyl derivatives, 2) SARS-CoV-2 peptides, and 3) α-amanitin and microcystin LR cyclic peptide toxins. We successfully produced broad and derivative-selective mAbs against eight fentanyl derivatives. We also showed early signs of success targeting neutralizing and mutant SARS-CoV-2 peptides with conformational specificity using a heterologous prime-boost strategy. Lastly, we produced high affinity mAbs for both α-amanitin and microcystin LR, two highly toxic cyclic peptides. The early success of mAb production against the variety of targets presented in this thesis shows the viability and exceptional versatility of conjugate VLP vaccines as a means to producing mAbs.