Organizational Unit:

College of Sciences

Permanent Link

https://hdl.handle.net/1853/70627

Includes Organization(s)

Organizational Unit

School of Biological Sciences

Organizational Unit

School of Chemistry and Biochemistry

Organizational Unit

School of Earth and Atmospheric Sciences

Organizational Unit

School of Mathematics

Organizational Unit

School of Physics

Show 1 more

ArchiveSpace Name Record

https://finding-aids.library.gatech.edu/agents/corporate_entities/1130

Full item page

Publication Search Results

Now showing 1 - 10 of 27

The effects of 40 Hz gamma flicker stimulation on spatial memory, perceptual discrimination, and recall

(Georgia Institute of Technology, 2022-08) Salen, Ashley

The rising prevalence of Alzheimer's Disease (AD), which leads to progressively deteriorating memory and thinking skills is alarming. A preliminary data analysis was performed to predict potential behavioral changes that may occur in cognitively healthy older adults between conditions as a result of using the flicker for 8 weeks. Although the preliminary data analysis has not yet yielded any statistically significant effects induced by the 40 Hz gamma flicker on the memory of the flicker group compared to the control group, it may provide insight into what the results could look like further down the line. Based on graph analysis, it could be predicted that the flicker group may have fewer spatial memory deficits.
Cyclic mechanical stretch upregulates Akt, MAPK, and NF-kappaB signaling pathways in BV2 microglia

(Georgia Institute of Technology, 2022-05-24) Udeshi, Kareena Jaydeep

Mild traumatic brain injury (mTBI) is prevalent in contact sports. Post injury, microglia in the central nervous system are known to produce an inflammatory response. Moreover, with repeated injuries, chronic inflammation may be sustained, which is detrimental to the host. This study focuses on the signaling pathways that are activated with brain injury-induced injury. We hypothesize that mechanical stretch activates inflammatory signaling pathways in microglia. This experiment utilized impulse, cyclic, and sham-stretch conditions in the presence or absence of the mechanosensitive channel inhibitor GSMTx4. Afterwards, the cell lysate was collected, and the samples were analyzed by a Luminex multiplexed ELISA to determine if there was a change in protein phosphorylation across 27 phosphoproteins in three main signaling pathways: Akt, MAPK, and NFkB. My data showed that GSMTx4 had little impact on phosphorylation, but it did increase the expression of the Akt pathway proteins. Nonetheless, the minimal role GSMTx4 played in the measured phospho-protein signaling pathways at acute timepoints could imply that Piezo1 does not play a direct role in acute pathway activation. Of note, however, a control 20% cyclic stretch resulted in an upregulation in phosphorylation in all signaling pathways. As such, future studies will include GSMTx4-treated BV2 microglia that undergo cyclic stretch at varying degrees. Clinically, this data is useful in understanding how sustained injury can force the progression of neurodegenerative diseases.
Measuring Cerebral Blood Flow in a Mouse Model of Alzheimer's Disease

(Georgia Institute of Technology, 2022-05) Daniel, Christy

Mild traumatic brain injuries (mTBIs), which are defined by an absence of overt structural damage in the brain have been associated with an increased risk of Alzheimer's Disease when sustained multiple times over an interval. Within mTBI, indirect evidence suggests that persistent post-concussive symptoms may be linked to reduced cerebral blood flow (CBF), of which deficits have been observed in cases of Alzheimer's Disease. Diffuse correlation spectroscopy (DCS) is a non-invasive optical method that uses near-infrared light to measure fluctuations in intensity that are caused by moving red blood cells that can be used to measure cerebral blood flow (CBF) in C57bl/6 mice. This dissertation will adapt this novel protocol to a mouse model of Alzheimer’s Disease (3xTg). This strain will be utilized due to its accelerated AD pathology and the presence of literature that have observed impairments in CVR, CBF, among other biomarkers of Alzheimer’s Disease and traumatic brain injury. Given the smaller size of the 3xTg mice compared to C57bl/6, the DCS optical sensor must be modified. Herein, the design of a smaller sensor is detailed, along with a series of validation tests, which include measurements on a liquid phantom with known flow properties and on a pilot cohort of four 6–7-month-old 3xTg mice (2 males, 2 females). This data provides the foundational work to characterize the feasibility of DCS as a technique to monitor CBF and CVR in 3xTg mice for future experiments.
The Effects of Nerve Injury and Synaptic Preservation on Motoneuron Activity

(Georgia Institute of Technology, 2022-05) Garcia, Violet

Peripheral nerve injury currently has a poor prognosis that often results in motor deficits such as discoordination and co-contraction of muscle antagonists (Brushart, 2011; Horstman et al., 2019). Because of this, studying the effects of peripheral nerve injury on the morphology and functional connectivity of the central nervous system (CNS) is of utmost importance. Our study centers around the anatomical changes that occur after peripheral nerve injury in the rat spinal cord, namely the degradation of Ia input defined by the expression of the vesicular glutamate transporter 1 (VGLUT1). This study is based on the proposed microglia-dependent mechanism of permanent synaptic loss from the Rotterman et al. (2019) paper. We ask if 1) we can suppress microglia accumulation with minocycline, a tetracycline antibiotic, and 2) if using minocycline can help preserve the Ia sensory afferent synapses after nerve injury. We first retrogradely labeled the medial gastrocnemius motor pool in 15 adult Wistar rats. One week later, we transected the medial gastrocnemius nerve in the left hindlimb. Rats were either treated with vehicle or minocycline for 14 days following injury. Control animals were also produced. At 14 days post injury, animals were perfused, spinal cords were collected and subsequently sectioned. Using immunohistochemistry (IHC), we labeled VGLUT1 synapses on these injured motor neurons and imaged them with confocal microscopy for subsequent reconstruction and analysis. We found four main results: 1) treatment with minocycline for 14 days after nerve injury does not seem to prevent microglia proliferation, 2) the chromalytic reaction (somatic expansion) that commonly occurs after axotomy did not seem to occur in the minocycline- treated animals, 3) there was partial preservation of somatic VGLUT1 synapses in the minocycline-treatment animals, and 4) there was complete dendritic VGLUT1 synapse preservation in the minocycline-treated animals. Although there were limitations to the study with regards to the methods of counting microglia, the study produced robust conclusions that will aid in the development of further research. Future studies should be conducted on the efficacy of minocycline preserving the synapses, the molecular mechanisms underlying minocycline’s effects, and the potential recovery of nerve function.
Improving Online Instructional Design using Memory, Attention, and Engagement

(Georgia Institute of Technology, 2022-05) Chanda, Ritika

Neuroscience research supports a relationship between the psychological constructions of attention and engagement. The level of selective attention and engagement present during the learning process correlates with increased memory and recall. With the recent rise in online learning, new questions regarding the improvement of educational design, teaching techniques, and learning have created a new avenue of investigation within the field of Neuroeducation. The objective of this study is to identify whether attentional brain networks related to Gagné’s Nine Events of Instruction and engagement can predict learning in an online setting by using fMRI and behavioral techniques. Overall, we found fMRI evidence of engagement, verified engagement’s role in memory and retrieval, and identified three Gagné events (Events 5, 6 and 7) that increase learning among students. This investigation allows for further advancements in online educational design as it will provide instructors with guidance on how to properly build their curriculum and modify the content structure of online classes to highlight techniques that promote successful learning.
Interaction between Burkholderia ceoncepacia and Staphylococcus aureus in Presence of Meropenem

(Georgia Institute of Technology, 2022-05) Wang, Runyi

In recent decades, chronic pulmonary infections have become the leading cause of death among patients with cystic fibrosis. Despite the large number of available studies that explore the effects of single-species bacterial infections, the dynamics of polymicrobial infections are not as well-understood. Initial pulmonary infections in patients with cystic fibrosis often involve multiple species. Therefore, it is important to identify the interactions between multiple bacterial species and the potential effects to patients during treatment. β-lactam antibiotics such as meropenem, are often prescribed by clinicians for infection treatment and management. However, Burkholderia cenocepacia is capable of producing β-lactam degrading enzymes β-lactamases. In this study, we show that B. cenocepacia’s production of β-lactamases has potential to rescue nearby bacteria that would be susceptible to the β-lactam antibiotics, such as Staphylococcus aureus. The study shows that S. aureus does not grow better in the presence of B. cenocepacia. This finding suggests that S. aureus is not being rescued by B. cenocepacia despite the β-lactamases produced. While it is probable that such relationship is detrimental to traditional treatment options, additional studies need to be conducted to definitively conclude its effects on treatment outcomes.
Hsp90 and the Evolution of Novel Cellular Differentiation

(Georgia Institute of Technology, 2022-05) Cheng, Vivian

Cellular differentiation is a prerequisite for complex multicellular life, yet little is known about how it evolves de novo. Several mechanisms may explain how early multicellular organisms evolved to perform cell-specific roles. In this work, I explore the potential role of cellular aging in driving age-dependent differences that evolve to become co-opted for a novel role in cellular differentiation. Specifically, I am examining how, in the snowflake yeast model system of nascent multicellularity, the Hsp90 class chaperone proteins have evolved to act in a novel age-dependent manner, thus driving the emergence of adaptive differences in protein activity among cells.
Including a Warm Corona within the Inner Accretion Disk of Active Galactic Nuclei

(Georgia Institute of Technology, 2022-05) Xiang, Xin

Warm coronae, Comptonizing regions of warm (temperature kT ∼ 1keV), and optically thick (Thomson depth ∼ 10 - 20) gas, at the surfaces of accretion disks in active galactic nuclei (AGNs), have been proposed to explain the origin of the soft X-ray excess commonly observed in the X-ray spectra of AGNs. We calculate the X-ray emission from an irradiated constant density accretion disk atmosphere that includes heating from a warm corona, as well as illumination from an external X-ray power-law radiation, and blackbody emission from the dissipation in the accretion disk. The model accounts for the radial dependence of disk ionization, including the effects of light-bending on the illuminating X-rays. The final spectra are produced by integrating the local reflection/emission spectrum from approximately 2 to 400 gravitational radii. We demonstrate how the soft excess in AGN X-ray spectra depends on the warm corona parameters, including the heating fraction and optical depth, and the strength of the X-ray illumination. The model will be publicly released in 2022 for use in fitting AGN spectra.
Modeling health and developmental effects of particulate matter exposure using C. elegans

(Georgia Institute of Technology, 2022-05) Thompson, Carys

Particulate matter (PM) is air pollution comprised of tiny particles suspended in the air. Exposure to PM is a major global health concern, contributing to 9 million deaths annually. Fine PM can break down protective cellular barriers and cause systemic inflammation, leading to damage of the central nervous and respiratory systems. Children are especially vulnerable to prolonged PM exposure due to breathing in toxins at a faster rate. Due to the limitations in the current approaches (e.g., cultured cells and mice models), specific biological mechanisms linking PM exposure to health hazards are still largely unknown. In this work, the microscopic nematode C. elegans is proposed to model the systemic and multi-tissue effects of PM at the cellular level. C. elegans is an excellent model organism due to its small size and fast life and reproductive cycles. Here we examined the oxidative stress response caused by prolonged oxygenated polycyclic aromatic hydrocarbons (oxy-PAH) exposure in larval C. elegans using a reporter strain for cellular redox status. Oxy-PAH has been recognized as a toxic component of PM. We find that although oxy-PAH exposure causes delay in larval growth, it does not affect redox activity, suggesting that oxy-PAH toxicity occurs through other biological pathways. The results of this study establish lab-manufactured oxy-PAH as a positive control and serve as a pilot study for ambient PM. Future work will focus on the health and developmental effects of ambient PM throughout larval worm development.
Reproduction and recruitment in perennial Vespula squamosa yellowjacket was colonies

(Georgia Institute of Technology, 2022-05) Crossley, Henry G.

Many people are all too familiar with social wasps of the genus Vespula, more commonly known as yellowjackets. What many people may not know is that recently, the nesting behavior of these wasps has begun to shift from a yearly cycle to a prolonged multiyear state. These perennial nests are becoming more and more common in areas with warmer climates. Using repetitive sequences of DNA known as microsatellites, allele frequencies, and strategies such as PCR, gel electrophoresis, and fragment sequencing, we worked to genotype eight perennial southern yellow jacket, Vespula squamosa, colonies from Auburn, Alabama to get a better understanding of the reproductive and genetic structure in these colonies. We then compared our data to that of annual colonies of the same species. We found that the relatedness is lower in perennial colonies than in annual colonies, and there is evidence in the genetic structure showing that perennial colonies contain more than one reproductive queen.