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Test Article by Sasquatch Jones
(Out of Focus Illustrated, 2011-12-21) Jones, Sasquatch; Jones, Sasquatch
EXPERIMENTAL AND NUMERICAL STUDY ON THE COMPARISON OF POINT-ABSORBER WAVE ENERGY CONVERTERS
(East Carolina University, December 2024) Cortez, Benjamin
The objective of this thesis is to investigate how buoy geometry affects the performance of point absorber wave energy converters. Five different buoy geometries were designed, each with the same initial diameter and total height. These models were then tested using the same experimental conditions. The experimental phase was conducted in a lab scale wave tank and involved the use of a LVDT sensor to measure buoy displacement, wave height gauges to measure water height, and a high-speed camera to record the experiments. The models were tested completely perpendicular to the water as well as at different angles with the water. ANSYS AQWA was used for numerical analysis of the buoys. The buoy models were modeled perpendicular to the water using the wave conditions that were recorded in the wave tank as well as the wave conditions that were recorded at Jennette’s Pier (Nags Head, NC) over five days. AQWA wave tank simulations output graphs depicting amplitude, radiation forces and gravitational forces for each buoy while the environmental simulations focused on amplitude only. Buoyancy forces were calculated for each model (perpendicular to the water only). The experimental results showed the overall trend that as angle of inclination increased, the buoy amplitude would decrease. The most likely reason why the ranges decreased as the angle of inclination increased was because as the LVDT sensor was inclined, the shield of the sensor began acting as an inclined plane creating friction between the sensor shield and armature. One model consistently outperformed the other models in both the wave tank and environmental simulations. The wave tank simulations also suggested a correlation between volume and buoy amplitude. There were differences between the experimental results and numerical wave tank results. This could have been because of friction between the sensor armature and shield, irregular wave shapes in the wave tank, certain parts not modeled in AQWA, and negative damping values in AQWA. Further studies into buoy geometry in point absorbers should examine performance changes when changing materials to examine the relationship between mass and buoy performance more thoroughly.
Islet Target Genes Required for Niche Assembly and Formation in Drosophila melanogaster
(2024-12-04) Ledbetter, Sophie I
A particular cell type, known as stem cells, possess a unique capability to self-renew and have the capacity to differentiate into mature cell types. To maintain stem cells, they require signals from a cellular microenvironment called the “niche. The stem cell niche regulates stem cell fate and has the ability to house and regulate a population of stem cells through intricate signaling pathways. Signals transmitted from the niche are important for stem cell self-renewal and cell differentiation signals, and proper signaling requires niche placement in a specific tissue location to polarize the tissue and get regenerated by new cells. Our lab currently studies the Drosophila testis stem cell niche in the male gonads of embryos. Distinct placement of the stem cell niche at apex (tip) of the testis tube organizes stem cells near the apex; cells undergoing differentiation will reside further down the testis tube. The niche forms during late stages of embryogenesis when pro-niche cells begin to migrate to the anterior region of the gonad and assemble the stem cell niche. The gonad niche tilts toward the visceral mesoderm (Vm), which sends Slit and FGF signals. In response to Vm signals, niche cells express the transcription factor islet, which is required for niche cytoskeletal polarization and anterior niche assembly (Anllo and DiNardo, 2022; Anllo et al., 2019). Recent single cell RNA sequencing data predicted Islet target genes that are expressed in the adult niche, and I prioritized testing three of these candidates: btk29A, kon-tiki, and scribble. My goals are to (1) identify if candidate Islet target genes are expressed in the embryonic gonad niche and (2) reveal whether these niche-expressed genes mediate niche assembly and function. My data revealed expressed of all three of these candidates in the niche, show that btk29A is required for niche assembly, and suggest potential roles for scribble, and kon-tiki in niche cells. Future experiments will confirm whether Kon-tiki and Scribble are required for niche assembly. Our understanding of the mechanisms that initially create a compartmentalized stem cell niche during development, in addition to anterior cell movement, will give us a more comprehensive grasp of how the niche is properly formed. These principles will help to clarify concepts about tissue function and development, including the activation of JAK/STAT signaling pathway for stem cell self-renewal, which is translatable to other systems (Leatherman and Di Nardo, 2008).
Assessing The Role of the Endocaanbinoid System in Arsenic-Induced Neurotoxicity
(2024-12-04) Cross, Monica Nicole
The endocannabinoid system (ECS) is an important brain pathway that plays a major role in early brain development and neural circuitry. The ECS has been found to regulate stress and emotional behavior during development. It modulates neural and behavioral stress and has also been found to be affected by stress exposure. The endocannabinoid system is a biological system that includes endocannabinoids and cannabinoid receptor proteins. Cannabinoid receptor 1 (CB1) has been found to control excitatory and inhibitory synaptic strength. The balance of these strengths is important and an imbalance in the strengths can contribute to autism spectrum disorder, epilepsy, and schizophrenia. Arsenic is a natural found heavy metal in air, water, and soil. It can disrupt the ECS by second- hand smoke, water contaminations, and industrial processes. Studies on arsenic's effects on the ECS are limited, but it is important to know the correlation between developmental defects and arsenic toxicities. iPSC in vitro 40 days neural organoid differentiation model mimics early brain development especially the 1st trimester during pregnancy.