Category: OSCAR

Multiscale Indentation-based Mechanical Characterization for Advanced Alloys Suitable for Aeroengine Applications

Author(s): Mariah Tammera

Mentor(s): Dr. Ali Beheshti, Department of Mechanical Engineering and Shaheen Mahmood, Graduate Student Advisor

Abstract

Multiscale indentation is a reliable method used to extract basic mechanical properties from
materials, particularly structural metals and alloys. Knowing and understanding the mechanical
properties is critical for engineers to effectively and safely design structures and components
based on specific environments, applications, or loads the materials will be subjected to.
Although indentation techniques have been previously utilized to determine basic mechanical
properties, such as elastic modulus, extensive progress has not been made towards the ability to
employ multiscale indentation for extracting advanced mechanical properties (e.g. creep
parameters and fracture toughness properties) in a reliable manner that produces results closer to
the bulk of the material. This project aimed to evaluate creep and fracture toughness properties
for Inconel 718 by utilizing micro-indentation techniques at room temperature. Analysis of the
material microstructure occurred via the use of the Scanning Electron Microscope (SEM). Due to
the limitation of conducting research in one semester, the learning objectives fulfilled were
performing indentation tests to extract basic mechanical properties (i.e. hardness values and
elastic modulus values) and conducting SEM analysis on the indentation site to evaluate the
success of the indentation tests and note observations about the material. Moving forward, future
work will concentrate on building upon the exploration of indentation techniques at room and
elevated temperatures to improve current ability to determine advanced mechanical properties of
material in an efficient and reliable manner.

Audio Transcript

Hi everyone, my name is Mariah Tammera. This fall, I was working under Dr. Ali Beheshti and
Shaheen Mahmood in the Tribology and Surface Mechanics Lab on Multiscale Indentation-based
Mechanical Characterization for Advanced Alloys Suitable for Aeroengine Applications.
Multiscale indentation is a reliable method used in the field to extract basic mechanical
properties from materials, such as the elastic modulus value, by understanding the relationship
between the indentation load versus penetration depth. However, extensive progress has not been
made towards the ability to employ multiscale indentation for determining advanced mechanical
properties, such as creep parameters and fracture toughness values, to acquire data that is reliable
and closer to the bulk of the material. This project intends to focus on evaluating creep
parameters and fracture toughness values for Inconel 718 by utilizing micro-indentation
techniques at room temperature. After the indentation tests are concluded, the Scanning Electron
Microscope will be utilized to analyze the indentation site. As you can see, Figures 1 and 2
showcase the equipment used in this project.
Before beginning any lab work, I worked on a literature review to learn about creep deformation
and what the fracture toughness of a material is. I conducted a literature search with the guidance
of Dr. Beheshti, to learn about what some of the commonly used experimental methods to extract
creep and fracture toughness are. From this preliminary literature search, it becomes clear that –
based on the findings – the literature has limited research on utilizing multi-scale indentation
techniques to determine creep parameters and fracture toughness properties at both room
temperature and elevated temperatures.
An indentation site matrix is a conventionally utilized technique to systematically map out
measurement locations on the sample surface. On the left, Figure 3 represents a 5×4 matrix that
was used to map out 20 places on the sample surface where the indentation tests will occur. As
noted on my slides it’s important that the location chosen for these indentation tests should be on
a smooth, flat area free of holes, pits and away from the edges of the sample.
Figure 4 represents an example of one of the micro-indentation curves obtained from one of the
20 indentation tests with indentation load on the y-axis and the penetration depth on the x-axis.
I’d like to point out the green box around the horizontal line up on the top right, which indicates
that the indentation load is constant here for 5 seconds.
From the 20 indentation tests, an elastic modulus value and hardness value were derived using
the Anton Paar Indentation software. The average elastic modulus value found was
approximately 160.04 ± 2.04 GPa and the average hardness value found was approximately 2.46
± 0.09 GPa.
After the indentation tests were successfully finished, the sample was taken and analyzed under
the SEM. Figure 5 is a close-up of one indentation sites, showcasing the square pyramid-shaped
Vickers tip and that the Vickers tip is sharp enough due to the precise diagonal lines across the
indentation site. Figures 5 and 6 are indicative of a successful indentation site due to minimal
plastic deformation, as we see minimal surface features, like raised lines or deformation bands
around the indentation site. Lastly, there is no visible cracking along the edges and outer corners
of the indentation site, which signifies that Inconel 718 is more of a ductile material.
Due to the limitation of conducting research in one semester, the learning objectives fulfilled
were performing indentation tests to extract basic mechanical properties and conducting SEM
analysis on the indentation site. Despite not completely fulfilling the projective objectives, the
results tell us that exploring multi-scale indentation techniques is a promising method to
determine advanced mechanical properties at room and elevated temperatures to obtain values
that are reliable and closer to the bulk of the material. The advanced mechanical properties
gleaned will only benefit future researchers and engineers regarding material selection in a
variety of field, particularly aerospace.
I’d like to thank George Mason University’s Undergraduate Research Scholars Program at the
Office of Student Creative Activities and Research for the funding that allowed me to contribute
to this project, and I’d also like to thank Dr. Beheshti and Shaheen for all of the mentoring,
training, and support they have each given to me. They are both dedicated professionals, and it
was a pleasure to work with them.
Lastly, these are my references. Thank you very much for your attention.

College of Science OSCAR Undergraduate Research Scholars Program (URSP) - OSCAR

Novel Biomaterial for Triple Negative Breast Cancer Dual Drug Immunotherapy Nylon-66 Affinity Thread

Author(s): Grace Lee

Mentor(s): Alessandra Luchini, College of Science

Abstract

Triple-negative breast cancer (TNBC) presents poor outcomes and relapse following chemotherapy. Joint delivery of anti-programmed cell death ligand 1 (PD-L1) and immune recruiting protein Chemokine Ligand 9 (CXCL9) has shown to be an effective immunotherapy for TNBC. Nylon, a synthetic polymer used in surgical threads, is promising for dual drug delivery due to its biocompatibility and drug-loading capabilities. Functionalizing Nylon 6,6 with Cibacron Blue F3G-A facilitates drug loading. This project assessed the functionality of Nylon 6,6 dyed with Cibacron Blue as a vehicle for dual anti-PD-L1 and CXCL9 TNBC immunotherapy.
Nylon 6,6 was dyed with Cibacron Blue and loaded with anti-PD-L1 antibody Atezolizumab (10 ng/µl) and CXCL9. It was stitched onto the breast tumor site of syngeneic (BALB/c) mice with ~1 cm-sized tumors from the 4T1 cell line. Mice were sacrificed three days post-implantation. Tumors were harvested for immunohistochemistry (IHC) analyses, applying biomarkers for apoptosis and immune cell infiltration. DAB and Hematoxylin staining imaged and characterized drug activity.
The study demonstrated that the thread induced immune cell infiltration and increased tumor cell apoptosis. Results indicate that Nylon 6,6 functionalized with Cibacron Blue is an effective biomaterial for targeted drug delivery. Future work includes confirmation of CXCL9 chemotactic abilities after release from the affinity thread and quantification of immune infiltration.

Audio Transcript

Hello! My name is Grace, and my project is on “Novel Biomateiral for Triple Negative Breast Cancer Dual Drug Immunotherapy Nylon-66 Affinity Thread.”
Triple-negative breast cancer (TNBC) is a leading cause of cancer mortality in women.1 TNBC cells upregulate programmed cell death ligand 1 (PD-L1), receptors that suppress immune recognition
Joint delivery of anti-PD-L1 and immune recruiting protein Chemokine Ligand 9 (CXCL9) has shown to be an effective immunotherapy treatment for TNBC. Anti-PDL-1 drug block the binding site of PDL-1 receptor on tumor cell and function as stimulator for immune cells to recognize tumor cell and kill it. CXCL9 function as immune cell chemoattractant that entices immune cells to the tumor site
Nylon, a synthetic polymer commonly used in surgical threads, shows promise as a vehicle for dual drug delivery due to its excellent biocompatibility and chemical stability. Moreover, its extensive porous structures and high aggregation capability greatly increases its drug-loading capacity. Nylon can be functionalized with Cibacron Blue F3G-A, which is a reactive textile dye that increases Nylon’s reactive sites while reducing non-specific adsorption, improving drug release accuracy and reducing toxicity. This project assesses the functionality of Nylon 6,6 as a vehicle of dual anti-PD-L1 and CXCL9 TNBC immunotherapy.
Nylon 6,6 was dyed with Cibacron blue and loaded with anti-PD-L1 antibody Atezolizumab (10 ng/ul) and immune cell chemoattractant CXCL9. The loaded thread was stitched onto the breast tumor site of the syngeneic (BALB/c) mice harboring ~ 1 cm-sized tumors from the 4T1 cell line. Mice were sacrificed three days post-implantation. Tumors were harvested for IHC.
Biomarkers for immune cell infiltration (Ly6G and F480) were applied on tumor tissues in a 1:300 and 1:500 dilution, respectively. Staining with DAB and Hematoxylin was performed to image and characterize drug activity.
The dual-loaded thread induced necrosis, whereas non-threaded tumors (control) remained healthy. The brown pigmentation in the right image reflects increased immune cell infiltration to the tumor site. You can also see holes on the right image, which represents dead tumor cells.
The thread can dually capture anti-PD-L1 and CXCL9 molecules (The loaded thread induced macrophage infiltration and increased tumor cell apoptosis The novel biomaterial Nylon 6,6 functionalized with Cibacron blue is an effective vehicle for targeted drug delivery Future directions include further proteomic characterization of thread-induced immune infiltration, quantification of immune infiltration, and confirmation of CXCL9 chemotactic abilities after release from thread

College of Engineering and Computing OSCAR Undergraduate Research Scholars Program (URSP) - OSCAR

Enhancing Steel Design Learning by Demonstrating Failure Modes in Steel Connections using Virtual and 3D Printed Models

Author(s): Omar Abu-Khalifa

Mentor(s): Doaa Bondok, Civil and Infrastructure Engineering

Abstract

In introductory steel design courses, students often work with complex and empirical design formulas that were developed through intensive research and were verified through observation rather than theory. Students often struggle with applying these design equations and need more visuals and illustrations to comprehend and use these formulas correctly. This research aims to investigate and propose methods to enhance the understanding of steel design concepts. These methods include 3D-printed connection models and creating illustrative interactive models to visualize concepts like buckling modes and block shear failure in tension members.

Audio Transcript

Hello everyone, my name is Omar Abu-Khalifa. I am a Civil Engineering major in my senior year of University and I’m here today to talk about Enhancing Steel Design Learning by Demonstrating Failure Modes in Steel Connections using Virtual and 3D Printed Models. To get started I want to first give a bit of an introduction to what my research project is focused on. Essentially, in introductory steel design courses, students often work with complex, empirical design formulas. Students often struggle with applying these design equations and need more visuals and illustrations to comprehend and use these formulas correctly. This research aims to investigate methods to improve student understanding of steel design concepts. These methods include developing 3D-printed connection models and creating an illustrative interactive model to visualize concepts likebuckling modes and block shear failure in tension members. Now, what were the goals of the research? When starting this research my mentor and I wanted us to print 3-D models of Steel Connections that demonstrate common failure modes, explore an illustrative interactive model that prospers student engagement similar to the model in figure 2, which was provided by AISC model viewer, demonstrates the failure modes for a double angle brace connection. The model shows tensile and block shear rupture failure. As research progressed, we shifted our goals to explore the implementation of Augmented Reality and Virtuality Reality softwares in education. This goal was based on reading I did over the summer when researching ideas. Now that the research goals have been discussed, let’s talk about the methodology. The first thing I did was conduct a thorough literature review. When conducting the literature review, I read articles that talked about utilizing lab spaces to study the failure in steel beams, conducting site visits so that students can see and visualize steel beams, having the professor use prerecorded lectures, among other things. The next step for me was to go to the MIX to get training in 3-D printing and exposure to 3-D printing. After getting exposure, I modeled standard steel beam-column and moment connections on AutoCAD and printed them. Look at figure 2 to see an example of a beam column connection. After printing, I explored the AISC interactive model viewer as seen in figure 2 and 3. Reflecting back on the research, I recognize that there are many more methods that could be done instead of 3-D printing models and using the interactive model viewer such as utilizing labs and conducting site visits but GMU resources do not allow for this, and planning the logistic behind this makes it more complicated. In addition, more research needs to be done on implementing AR and VR softwares in an education setting. In the future, this research can be expanded by evaluating the effectiveness of the teaching aids, further explore AR and VR softwares, and to continue working on the modeler. I’d like to acknowledge OSCAR, the Civil Engineering Department, AISC, Dr. Bondok and Dr. Lee. Thank you all for your time.

College of Engineering and Computing OSCAR

Relationship Between Eye movement and Eye Muscle on Ultrasound

Author(s): Andrew J Ryan, Zeinab Elahy

Mentor(s): Qi Wei, Bioengineering

Abstract

The advancement of bioimaging technologies has significantly progressed in recent years, which can be used to image many parts of the body. However, despite these developments, the human eye remains relatively understudied in dynamic imaging. By utilizing ultrasound imaging, we can learn more about the movement of the eye muscles while the eye is moving, particularly the medial rectus muscle (MRM). This can provide new avenues for diagnostic capabilities. The purpose of this study was to analyze the relationship between eye movement and the MRM echo-intesnity (echo-texture) on ultrasound. We hypothesized that there is a periodic relationship between eye movement and muscle echo-texture. In this study, we utilized eye data from multiple subjects. Our team obtained IRB approval to obtain images, with all participants providing consent before enrolling in the imaging study. The participants were asks to move their gaze from left to right and vice versa, following a target. This gave us series of image stacks, containing an average of 220 frames. Using MATLAB App Designer, we created an application that can load image stacks of ultrasound; shade in, annotate, and trace the MRM; and save the tracings as a MATLAB cell struct file. That file was then subsequently processed in another code, using MATLAB regionprops function, to produce a figure that quantifies the muscle echo-intensity (tracings) over gaze (frames). The results suggested that there is a periodic relationship between MRM echo intensity and eye movement. More data must be collected to acquire a more accurate interpretation.

Audio Transcript

Hello everyone, I’m Zeinab and my URSP research was analyzing the relationship between eye movement and extrocular muscle movement on ultrasound images. This was in collaboration with the Bioengineering Department at George Mason.

So extrocular muscles are just a fancy word for eye muscles. The eye muscles we focused on for this research was this muscle, the medial rectus muscle. And it’s the muscle that is closest to the nose on both eyes. So this right here is the right eye. Here we have, this would be the nose and this muscle is basically in charge of moving this eye toward the nose.
So it’s in charge of moving the right eye to the left and on the opposite side same thing.
It’s in charge of moving the left eye to the right. And any problems with this muscle could result in double vision or being cross-side. So how would a doctor and eye doctor examine that or examine the eyes in general?

Well there are different methods to take images of the eye, there’s retinal imaging, which is probably the one most people have had taken before. That provides information on the optic nerves and your vision. In serious cases, the doctor might want to look at the bone structure or muscles in the surrounding areas of the eyes. And that’s when they would use X-ray or CT or MRI imaging. These are all very innovative, but the problem is they provide still images. What if we want to somehow image or compile a video of the eye while the eye is moving or look at it in real time?

That’s when we turn the ultrasound imaging. A clinician or a technician will run a small probe on your eyelid or under the eyelid. The patient might keep their eye closed or open depending on the procedure. And that will get you this image right here. Ocular ultrasound imaging is used a lot. It can be used to find foreign bodies such as tumors and blood pooling and to evaluate any trauma in the eye, evaluate the optic nerve, any lens detachments. However, there are no studies on evaluating how the muscle changes.
And we can only see that change when the eye is moving. So that’s the topic we wanted to research.

What is the relationship between eye movement and the medial rectus muscle’s echo intensity? And by echo intensity, I mean the ultrasound image pixel intensity of the muscle,
which can kind of quantify as the general shape of it.

For my research, we conducted ocular ultrasound on multiple participants,
multiple trials. In order to process those movements and segment that muscle intensity,
we used MATLAB app designer to trace the MRM on each ultrasound session, tracing every 5 to 10 frames. And then we used MATLAB to convert those tracing into a figure and quantify the results.

All right, so first we have one example of an ultrasound image stack that we took. This is the right eye. And here’s the pupil area right here. So we asked the participant to move their eye left and right while looking at a target. I know it looks like it’s going up and down,
but that’s just because of the position of the probe. And down here is the medial rectus muscle. And as you can see, you can already see the muscle changing. The echo intensity and the shape is changing while the participant is moving their eye left and right.

And just the screen recording of how I did this,as you can see, I have the image stacks loaded here on the MATLAB app. There are 224 frames in this one. I can move them around and I traced every 5 frames or so. And to demonstrate right here is the medial rectus muscle. And so I traced right around that outline. I normally do this zoomed in, but for demonstration purposes, I zoomed out. And then I would go to the next frame. Again, normally I would do it every 5 to 10 frames, but I’ll just trace this one right here. And then after that, I would save the annotations of all the traced muscles
as a MATLAB cell-struct file.

All right, so after processing that, here is one of the ultrasound sessions. And this is the figure that we were able to generate. The y-axis is the muscle intensity while the x-axis is the frame. And again, we can correspond frame with time or as the muscle, as the eye moves. Excuse me. And so these blue dots are representatives of the tracings that I did
and this red line is the periodic regression that we fitted it with. And to kind of illustrate that right here, you can see the beginning frames, the beginning segments that I did. They’re kind of similar. So the muscle was hardly moving, which means the eye was probably not moving. And so if I press play right here, we can see that is true. Okay, right now for those first few seconds, the eye was not moving. So we can say up to frame 60, 50 or so. The eye wasn’t moving and so the muscle wasn’t moving. The muscle wasn’t changing. You could see the shaded areas that I would do were probably not, not too different from each other.
And so right now, the eye moves to the left. It moves to leftmost and this is probably where the leftmost is. And so the muscle echo intensity, you can see here it’s a lot smaller. It’s almost really thin. That means the echo intensity was going down, which again is shown here. That makes sense. So much so that right here, when the eye just changes direction,
so probably around 80, right here. Around frame 80, the eye starts to change direction. And so the muscle is getting bigger as the eye is moving to the right. And that again makes sense. The eye moves to the right, the muscle echo intensity just gets bigger and bigger. Up until this peak right here, again, the eye changes direction and starts to move to the left. And we have that cycle again, comes back now. And again, notice the muscle echo intensity is very big and then it starts to get small again. So we can conclude that at every peak, that’s represented at the eye changing direction because the muscle changes shape.
And so we can say that there is a relationship between gaze and muscle echo intensity. These results suggest it. They don’t necessarily say it, but they suggest it.

Now, there were some limitations to these methods. First off, it was very time consuming.
Tracing every 10 frames took about 10 minutes. Tracing every be 5 frames took longer, about 15, 20 minutes. Now, that doesn’t seem long, but every participant conducted 6 trials. So compiling all the tracings were just one participant takes anywhere between an hour to an hour and a half. Another limitation was that some of these images of the eyes
were bit unclear, which made me not trace it at all sometimes. So if you can see in this image right here, there’s a giant gap between these two frames. I didn’t take any images here or any tracings here because it was just hard to see on the ultrasound. And so that created this giant decrease in the regression. And that would not create some accurate results. Another thing was that there were some problems with the coding and the apps.
And so we spent a lot of time troubleshooting and debugging. And finally, the results were very promising. However, we would need more participants, more data in order to reach a better conclusion.

And so our next steps would be to gather more data from more participants. And then again, because tracing is time consuming, we would want to look into possibly making the tracing process automatic using machine learning processes. And then we can analyze how the maximum muscle thickness changes as the eye moves as well. And for long term, we can examine the same relationship with the other five extracurricular muscles.

All right, so to conclude, again, we found a periodic relationship between the MRM and gaze. In general, ultrasound is a very useful imaging technology. This type of research is very novel and innovative. Research on the eye and eye movement, though fairly understudied, has a promising future with these types of developments. And special thanks to OSCARS for their URSP funding, our participants of the study, the Department of Bioengineering, especially Dr. Wei and the Biomechanics Lab. Thank you very much for watching.

College of Engineering and Computing Honors College OSCAR

Technology of Tomorrow

Author(s): Alexia De Costa

Mentor(s): Kasey Thomas, University Life

Abstract

This project merges art and technology through an interactive installation that showcases innovations from the Mason Autonomy and Robotics Center (MARC), including ground robots and computer vision. Created through interdisciplinary collaboration, the collection explores the relationship between creativity and technological progress. The first piece, Trailblazers, features ground robots navigating a maze of hedges that resemble the George Mason University logo, while The Digital Mirror reinterprets René Magritte’s The False Mirror to explore computer vision and machine perception. These immersive artworks invite viewers to engage with technology in accessible, thought-provoking ways to foster a deeper connection between people and the technology shaping our future.

Audio Transcript

Art and technology have traditionally been viewed as separate domains, but my project bridges these two areas through the creation of an interactive art installation. This installation showcases some of the remarkable innovations developed at the Mason Autonomy and Robotics Center (MARC), where cutting-edge technology like blimps, ground robots, computer vision, artificial intelligence, and advanced algorithms come to life. By integrating these elements into art, the project aims to highlight the interplay between creativity and technological progress, fostering a deeper appreciation and understanding of both.
The collection itself was developed with the help of students from diverse academic backgrounds. Our collective effort brings together expertise in robotics, computer science, engineering, and the arts, emphasizing the power of interdisciplinary collaboration in creating innovative experiences.
The first piece in the collection, Trailblazers, focuses on the ground robots developed at MARC and their interactions with their surroundings. This artwork features a maze of hedges inspired by George Mason University’s logo, symbolizing innovation and growth. The robots in this piece are equipped with LED-lit spheres that diffuse light, creating a visually captivating effect.
The panels of the piece were laser-cut to accommodate the embedded LEDs. As viewers approach, an ultrasonic sensor detects their movement, activating lights that trace a path through the maze. This interaction mirrors how the ground robots navigate and adapt to changes in their environment. By blending technical precision with artistic design, Trailblazers provides a dynamic sensory experience that showcases the advanced robotics research at MARC and how robots can engage with physical spaces in meaningful ways.
The second piece, The Digital Mirror, offers a contemporary reinterpretation of René Magritte’s The False Mirror which is a surrealist painting depicting a solitary eye reflecting a cloud-filled sky. In this piece, the eye is animated with a servo, camera, and linear actuator, allowing it to move left and right as it follows certain colors in its surroundings.
At the heart of this piece is an exploration of computer vision. The pixelated image within the iris represents how computer vision interprets the world in discrete pixels, while the more detailed background symbolizes the richness and complexity of real-world conditions. This contrast between clarity and abstraction reveals both the imperfections and the incredible potential of computer vision technology. Through its design, The Digital Mirror invites viewers to reflect on how machines perceive the world and the challenges of bridging the gap between digital interpretation and human experience.
These artworks go beyond static displays, they are immersive, interactive experiences that engage audiences on multiple levels. By integrating technology into art, the pieces invite viewers to explore the possibilities of robotics and computer vision in ways that are accessible and thought-provoking. This fusion of creativity and innovation not only highlights the groundbreaking work at MARC but also opens the door for wider conversations about how technology can shape our future.
Through pieces like Trailblazers and The Digital Mirror, this project aims to inspire curiosity and foster a deeper connection between people and the technologies transforming our world.
I would like to express my sincere gratitude to my mentor, Ms. Kasey Thomas, for her invaluable guidance. I am also thankful to Dr. Missy Cummings for her continued support of this project through the MARC. My heartfelt thanks go to the team of students who contributed, and to Dr. Lee, without whom this project would not have been possible. Thank you.

College of Science Honors College OSCAR

The Effect of Ethylene Glycol on Homomeric α1 Glycine Receptor Function in Xenopus Laevis Oocytes

Author(s): Fae Jensen

Mentor(s): Greta Ann Herin, Neuroscience

Abstract

Ethylene glycol is a common environmental contaminant, as it is a primary component of the solution used in fracking. It remains in the soil and groundwater of fracking sites, therefore causing it to have a sustained effect on both human and other biological life in these areas. Ingestion of ethylene glycol inhibits central nervous system (CNS) functioning, though the specific neuronal mechanisms of this depression are currently unknown. To address this gap in knowledge, this project seeks to determine if ethylene glycol modulates glycine receptor function in a concentration dependent manner. This will be done by microinjecting Xenopus Laevis oocytes with RNA of the α1 subunit of glycine receptors (GlyRα1). Once the receptors are expressed, Two Electrode Voltage Clamp (TEVC) electrophysiology will be used to record transmembrane current caused by Cl- influx through the ion channel pore of the receptors. As GlyRs are one of the primary inhibitory neurotransmitter receptors of the CNS, these recordings will potentially identify a method by which CNS functioning is modulated by ethylene glycol.

Audio Transcript

Hello! I’m Fae Jensen and I am currently studying the effects of ethylene glycol on glycine receptors of the alpha1 subtype in Xenopus Laevis oocytes and I’m doing this in Dr. Herin’s lab.

The purpose of my experiment is to determine the effects of ethylene glycol on homomeric α1 glycine receptors expressed in Xenopus oocytes and whether these effects occur in a concentration-dependent manner.

Ethylene glycol is a widespread environmental contaminant due to its use in fracking solution. When ingested, it functions as a CNS depressant, though the mechanisms of this depression are currently unknown. Because of this, I’m studying its effects on glycine receptors. This is because when glycine binds to the two binding domains on glycine receptors it causes a conformational change in the receptor which allows the ion channel pore to open, thereby allowing Cl- ion influx into the cell. This Cl- influx brings a negative charge along with it, which can have a hyperpolarizing effect on the cell and overall causes a decreased likelihood for action potential generation, thereby causing CNS depression.

In order to do this I’m using Xenopus Laevis oocytes which are the preferred model system for the study of receptor and ion channel physiology due to their size and membrane durability.

My hypothesis is that Cl- influx through the ion channel pore will increase in a concentration-dependent manner upon exposure to ethylene glycol. I propose this will be the case because ethylene glycol and ethanol have a very similar chemical structure, as you can see here, and I believe this will therefore cause ethylene glycol to bind to the same domain on glycine receptors as does ethanol. And because ethanol is known to allosterically increase glycine receptor response when it binds to this domain.

In order to conduct my experiments, I first start out by checking my cDNA samples for quality assurance. I then replicate the DNA sample if need be, and then transcribe it into mRNA so that it can be translated into proteins once injected into the cytoplasm of cells.
Following this process, I then very controlledly inject 0.05 μL of GlyRα1 RNA into each Xenopus laevis oocyte. I allow the oocytes to incubate for 1-3 days to allow for GlyRα1 proteins to be expressed on the membrane.
I then record from the each oocyte using Two Electrode Voltage Clamping. By clamping this voltage, I am then able to record the actual ion currents which are flowing across the membrane through glycine receptors and other ion channels.

While recording I first begin by perfusing plain ND96 over my cell in order to obtain a baseline recording. I then perfuse my cells with 1 mL of each of my experimental solutions, washing the cell out with ND96 between each solution. This is completed in a randomized order and for sets of solutions consisting of a fixed amount of glycine and varied concentrations of ethylene glycol, as well as for solutions consisting of a set amount of ethylene glycol and varied concentrations of glycine. This allows me to observe how ethylene glycol modulates glycine receptor function in real time, as well as determine whether glycine receptors respond normally to increased concentrations of glycine when exposed to ethylene glycol.

Here are the results from my recordings studying the glycine receptor’s response to various concentrations of glycine while in the presence of 300 uM of ethylene glycol, with the concentration of glycine along the x-axis and the average normalized current from five cells on the y-axis.

And here is my concentration response curve for ethylene glycol recorded across five cells. All of these recordings were taken from cells from the same frog so endogenous ion channel expression may affect these results, but as of yet it is looking like ethylene glycol may in fact potentiate the glycinergic current at concentrations of 300 uM and higher.

Here are my references.

So, finally I would like to give a big thanks to Dr. Herin for her continuous support and mentorship throughout this project, and I would like to thank the OSCAR program for providing me funding in the form of URSP grants. Thank you!!

College of Humanities and Social Science OSCAR

The Effect of Ionotropic and Non-ionotropic NMDAR Signaling Domains on Postnatal Development of LTD Using Chimeric GluN2 Mice

Author(s): Bryce Sullivan

Mentor(s): Theodore Dumas, Neuroscience

Abstract

The hippocampus, which is a brain region essential for information processing, learning, and memory formation, undergoes critical periods of heightened experience-dependent changes to neuronal structure and function (plasticity). N-methyl-D-aspartate receptors (NMDARs) are necessary for this process in excitatory hippocampal synapses through synaptic strenghening (long-term potentiation, LTP) and weakening (long-term depression, LTD). NMDARs have been shown to behave both ionotropically and nonionotropically, and that specific domains on the GluN2A and GluN2B subunits contribute to synaptic plasticity. In mice, the third postnatal week (~three years old in humans) marks the onset of mature learning and memory and is the result of a shift of dominance from GluN2B to GluN2A subunits. In this project, the impact of individual NMDAR GluN2 subunits signaling streams on the hippocampal development of LTD. This was done using chimeric that contain either GluN2A or GluN2B with the carboxy terminal domains (CTDs) swapped (i.e. Glu2A-BCTD and GluN2B-ACTD), which allows isolation of the ionotropic and nonionotropic signaling properties of each GluN2 subunit. A 1 Hz stimulation was used for 15 minutes to induce LTD in CA1 of hippocampal slices of these chimeric constructs and wild-type (WT) and the field excitatory post-synaptic potentials (fEPSPs) were recorded. While more data needs to be collected and analyzed, these experiments will provide a better understanding of how ionotropic and nonionotropic NMDAR signaling domains regulate the late postnatal development of LTD.

Audio Transcript

Hello everyone! My name is Bryce Sullivan, and my projected is looking at the effect of ionotropic and non-ionotropic NMDAR Signaling Domains on Postnatal Development of LTD Using Chimeric GluN2 Mice

The hippocampus, named after its seahorse-like shape in humans, is an essential brain structure for spatial learning and memory in adults. Development of the hippocampus occurs in the late postnatal period and coincides with the emergence of adult-like spatial learning and memory abilities at around three years of age in humans, or three weeks of age in rodents.

Synapses are the electrochemical junctions between neurons that allow for neural circuits to be built and to process information. The ability of excitatory synapses in the hippocampus to alter their function with new experiences and create neural substrates of memories is referred to as synaptic plasticity.” The final maturation process of the hippocampus involves modifications in synaptic plasticity.

In our lab, we study the NMDA receptor, NMDARs, which are essential for activity-dependent plasticity at excitatory synapses. The prominent forms of synaptic plasticity induced by NMDAR activation are long-term potentiation, LTP, and long-term depression, LTD. So, when a synapse is activated at high frequencies, NMDARs respond by sending signals to strengthen that synapse, which is LTP. However, when a synapse is activated at lower frequencies, NMDARs send a signal to weaken that synapse, which is LTD.

NMDARs are ion channels that allow calcium to enter the activated cell. It is well known that calcium activates synaptic plasticity processes. However, in 2013, it was discovered that NMDARs produce signals that are not related to calcium, that are mediated by the intracellular portion of the NMDAR subunits.

To study separate influences of calcium-dependent and calcium-independent signals, our lab created chimeric NMDAR subunits. I am using mice that express chimeric NMDAR subunits to investigate which NMDAR signaling pathways underlie the development of LTD. My electrophysiological recordings take place on postnatal day (or P) 17 to 19 and P22 to 24. These two age groups represent the immature hippocampus (younger than three postnatal weeks) and the mature hippocampus (older than three postnatal weeks).

My project’s primary three methodologies consist of genotyping, hippocampal slice prep, and hippocampal slice recordings of field excitatory post-synaptic potentials (fEPSPs) in CA1. Genotyping consists of taking small tail snips of our mice, DNA precipitation to isolate a DNA sample from that tail, running a polymerase chain reaction (or PCR) to isolate and amplify our chimera genes (if present), and then running a gel electrophoresis to find their genotype.

Hippocampal slice preparation is as it sounds; sacrificing the mouse, dissecting and isolating the hippocampus, and cutting the hippocampus into slices that are about a half a millimeter thick. These slices can be maintained alive in a recording chamber for many hours.

To record from hippocampal slices, we use two electrodes as this sample image (A) shows here. The bipolar electrode here is a platinum-iridium wire that activates the input neurons that project to area CA1. Synaptic responses are recorded in area CA1. The waveform in B represents an excitatory synaptic potential. The dotted line shows how we measure the slope of this response.

When LTP is induced, the EPSP gets larger. When LTD is induced, the EPSP gets smaller. For our LTD protocol, we use a 1Hz stimulation for 15 minutes.

It is well known that low frequency stimulation elicits LTD to a greater extent in immature mice. However it is not known if this reduction in LTD with increasing age is due to changes in calcium-dependent or calcium-independent NMDAR signaling. Performing LTD experiments in mice that express chimeric NMDAR subunits allows for testing of these two different possibilities.

I would finally like to thank OSCAR for providing me funding for my project with the URSP program and Dr. Dumas along with the rest of the PBNJ lab for their support and mentorship. This is not the present PBNJ lab, but I felt as though this photo from before 2015 was appropriate

And here are my references

College of Engineering and Computing OSCAR

Using AI to Quantitatively Analyze Extraocular Muscle Pulley Morphology from MRI

Author(s): Jahayra Guzman-Rivas

Mentor(s): Qi Wei, Bioengineering

Abstract

Strabismus is the misalignment of the eyes, which can be caused by abnormalities in the pulley connective tissues. Magnetic Resonance Imaging (MRI) is used to study the structural and biomechanical features of strabismus. Recently, artificial intelligence (AI) techniques, specifically deep learning, have been implemented in segmenting the images obtained by MRI. However, these techniques need improvements for more accurate depictions of the structures. MRI images from patients with strabismus containing the extraocular muscle pulley morphology were obtained. Deep learning techniques will be used to locate the muscles using pixel-based labeling. Then, segmentation masks will be created containing the muscles with various colors. These locations will be analyzed through two F-measure-based metrics. These metrics are the Intersection of Union (IoU) and the Dice coefficient. While results have not yet been determined, the techniques are expected to accurately show the location of each extraocular muscle through different colors representing each muscle. These techniques are also expected to obtain IoU and Dice scores of close to 1 to show a complete overlap between the original MRI image and the image of the predicted locations. These refinements in the segmentation process will significantly enhance the performance of AI segmentation used for studying strabismus in medical imaging.

Audio Transcript

Hello everyone. My name is Jahayra Guzman-Rivas, and I am a bioengineering student at George Mason University. Today, I will be talking about my research in using artificial intelligence to quantitatively analyze the extraocular pulley morphology from MRI.

It is important to first understand Strabismus for this research project. Strabismus is the misalignment of the eyes. This condition occurs in 0.5 to 5 percent of the global population. Strabismus can be caused by abnormalities in any of the six extraocular muscles and their pulley systems. These five muscles are the medial rectus, lateral rectus, inferior rectus, superior rectus, and superior oblique.

When strabismus is examined in patients, magnetic resonance imaging, or MRI, has been implemented in the clinical spaces as it looks at the neuro-biomechanical factors of eye movements.

However, there are limitations to the use of MRI. When clinicians and trained experts segment the extraocular muscles and other ocular structures manually, it can be very time-consuming and labor-intensive.

In recent years, a specific field of study in Artificial Intelligence, specifically deep learning, has been applied to the process of segmenting the muscles in the eyes. Deep learning is a method in AI that instructs computers how to process data using neural networks. However, these techniques must be improved.

My research involves using deep learning methods to locate extraocular muscles using pixel-based labeling. I will be using MATLAB to implement deep learning methods. I will also use data collected from 13 patients. This data was collected at UCLA and intended for research purposes only.

Before I started using the deep learning methods, I conducted extensive literature reviews to further understand the anatomy of the eye and the utilization of deep learning methods.

I also confirmed which data is available and noted them in a summary sheet.

After noting the available data, I started preparing them for the deep learning methods. I looked at the images for each slice of each muscle for each eye for each patient and renamed them according to their slice and muscle using ImageJ. I then compiled all the slices of all the muscles of each eye of each patient in one folder. This process took about one month as I had 13 patients and 1,662 images to look at.

Since the code I obtained to create the masks required the slices for each eye for each patient to have a different naming format, I had to create new code in MATLAB that organized them into the right format. This took me about a week to complete.

I then used these stacks of images to create masks of the five muscles and have them shown in various colors.

As for the next steps, I must implement them into the deep learning model to train it with masks for each patient for each eye, validate the model, test the model, and adjust the model as needed.

While I made a lot of progress on my project, I could not complete it within this semester. However, I was able to gain a lot from this experience. For example, I was able to enhance my coding skills with MATLAB. Additionally, I gained a better understanding of deep learning algorithms and their implementation in segmentation. I also learned that preprocessing the data before implementing the deep learning methods are critical to the model’s training process.

I want to express many thanks to Dr. Lee and the George Mason University Office of Student Creative Activities and Research as they helped fund this research through the Undergraduate Research Scholars Program. I also want to thank my mentor, Dr. Wei, for guiding me throughout this process. I want to acknowledge Amad Quereshi for guiding me and providing the code needed for my research.

Thank you!

College of Engineering and Computing OSCAR

An Evaluation of Viewpoint Diversity and Polarization Measurement Techniques

Author(s): Reva Hirave

Mentor(s): Antonis Anastasopoulos, Computer Science

Abstract

Polarization and viewpoint diversity are central to understanding online discourse, as they shape public opinion, influence democratic processes, and impact social cohesion. This literature review examines existing methods to measure polarization and viewpoint diversity in unstructured and dynamic online conversations. It categorizes approaches into three primary paradigms: content-based, network-based, and interactional methods. Content-based methods leverage linguistic features like sentiment and topic modeling but often face challenges with unstructured data and dataset biases. Network-based approaches model user interactions, such as replies and co-occurrences, to identify segregation and shared vocabularies, though they grapple with scalability and interpretability issues. Interactional methods delve into conversational dynamics, focusing on engagement patterns, emotional escalation, and argumentation, yet remain computationally intensive and context-dependent.

The review highlights the strengths and limitations of each approach, emphasizing the need for interdisciplinary methods that combine textual analysis, network modeling, and interactional dynamics. By synthesizing these perspectives, this review identifies gaps and future directions for developing comprehensive and adaptable metrics to better understand polarization and diversity in online conversations.

Audio Transcript

hello my name is Reva Hirave and I’m a fourth year computer science student this is my project an evaluation of viewpoint diversity and polarization measurement techniques this project was done under the mentorship of Dr an asopos with the Department of computer

science it’s not a secret that social media plays a huge role in shaping public opinion it’s a place where people from all over the place can come together exchanging ideas and perspectives but it’s also where we see some of the sharpest divides and this is often in the form of of ideological polarization understanding this is crucial not just for social science research but also for real world issues like content matter content moderation and the way online communities evolve so what’s the problem online conversations don’t always have clear boundaries conversations can Veer off in tangents topics shift super quickly and these contexts are always changing so this makes it really hard for researchers to analyze what’s actually going on in these digital spaces so the working research question for this project is how can we develop robust and and adaptable metrics to measure ideological polarization and Viewpoint diversity in online conversations across different social media

platforms to tackle the to tackle these issues researchers currently use three main methods to study these online interactions content based network-based and interactional these approaches each focus on a different aspect of online communication content-based methods look at the actual words people are using network-based methods track how people interact with each other and Inter and interactional methods focus on the back and forth Dynamics so how do people actually respond to to each other in conversation so we’re going to go a little bit deeper into these first let’s talk about content based methods these analyze the actual content of conversations it’s all about the words that people are using and what these words mean um sentiment analysis is one example where text is classified as positive negative for neutral and emotion an Anis takes this one step further tagging text with emotions like anger Joy or fear another useful tool is topic modeling which helps identify themes and conversations this lets us see how different user groups are talking about the same topics but there’s still some but there’s still some challenges here social media data is messy and unstructured and it can vary a lot across platforms plus annotated data sets used for training these models can often be biased which can affect the accuracy of results next next let’s look at network-based methods these focus on how users interact with other with each other for example how often do users do users reply to each other like post or share content there are two key types of networks we analyze here first we have interaction networks which show how users are connected through their actions you might notice P patterns where like-minded people tend to tend to engage with each other and form their own clusters and this can contribute to the ideological Echo chamber effect that we mentioned earlier second co-occurrence networks look at how different vocabularies emerge within groups if we track which groups or which words tend to appear together we can see if different groups are using different um different forms of language however as you might guess these methods do come with challenges of their owns um as analyzing vast amounts of data can be pretty difficult and interpreting these large networks is a whole other is a whole other mess finally we have interactional methods these methods dive into into the Dynamics of conversation itself are these interactions constructive or confrontational are users building on each other’s ideas or just attacking each other a major concern here is that is that marginalized viewpoints often get disproportionately negative feedback this this can actually create a lack of inclusivity and can deepen polarization further we also look at argumentation are people making fact based fact-based points or or emotional appeals another interesting Tren trend is emotional escalation negative emotions like fear and anger tend to spread especially in response to confrontational interactions still these methods have limitations of their own because they’re very context dependent what works on one platform and on one topic might not work on the other and they and these uh and these can also be super computationally expensive to analyze just because there are a lot of interactions that happen that happen on these

platforms so so to summarize understanding understanding polarization and Viewpoint diversity is really important for for understanding the broader impact that online discourse has on society and democracy by using content based network-based and interactional methods we can get a much clearer picture of how people are communicating online but there’s still a lot of work to be done we need to develop more more more robust metrics to track polarization and Viewpoint diversity across different online environments and that’s why my spring 2025 USP project will focus on creating a comprehensive adaptable framework for measuring polarization across a variety of online context hopefully this will help us understand these Dynamics better and ultimately improve social media platforms for everyone thank you for watching

College of Humanities and Social Science OSCAR

Binaural Beats on Attention

Author(s): Alisha Jane Hiskey

Mentor(s): Martin Wiener, Neuroscience

Abstract

Binaural beats is a non-invasive and inexpensive nonpharmaceutical potential treatment for disorders of attention, among many others. Binaural beats are a phenomenon that occurs when two sounds with slightly different tones are played to each ear. The brain synthesizes these varied amplitudes into one cohesive sound that oscillates back and forth. There has been some recent research into the effectiveness of binaural beats in improving areas like sleep, meditation, memory, and attention.
The Brainwave Entrainment Hypothesis suggests that after being exposed to a specific frequency of sound, the brain will adjust and mirror that activity on a similar frequency (Ingendoh, 2023.) A 22 study meta-analysis adds to the growing evidence that binaural-beat exposure is an effective way to affect cognition”¦ without prior training” (Garcia-Argibay, 2019.) However, more work can be done as there is a lack of studies examining the effects of binaural beats on autonomic activity in relation to cognition” (Chee, 2024.)

Audio Transcript

Hello, my name is Alisha Hiskey. I am pleased to share my presentation on binaural beats. Binaural beats are a phenomenon that occurs when two sounds with slightly different tones are played to each ear. The brain synthesizes these varied amplitudes into one cohesive sound that oscillates back and forth. There has been some recent research into the effectiveness of binaural beats in improving areas like sleep, meditation, memory, and attention. This project works to investigate the surrounding effects of various binaural beats recordings on attention. The Brainwave Entrainment Hypothesis suggests that after being exposed to a specific frequency of sound, the brain will adjust and mirror that activity on a similar frequency (Ingendoh, 2023.) A 22 study meta-analysis adds to the growing evidence that binaural-beat exposure is an effective way to affect cognition over and above reducing anxiety levels and the perception of pain without prior training” (Garcia-Argibay, 2019.) However, more work can be done as there is a lack of studies examining the effects of binaural beats on autonomic activity in relation to cognition” (Chee, 2024.) In response to this call to action, a task called a temporal bisection has been created that evaluates aspects of attention such as reaction time, precision, and response bias. Three groups are going to be divided and either a binaural beats frequency or pink noise (control) are played for the participant 10 minutes before and during then the task. During one cycle, the task requires the participant to respond short or long” to a stimulus shown 300-900ms. Each frequency that is played can be conducive to various brain states like one of sustained attention and cognitive power when entrained in the beta or gamma range. The shifting from high energy/anxious states into more relaxed and focused ones could help people with ADHD, ADD and other related attention deficit disorders. After this experiment, there can be added information on the effectiveness of binaural beats in the world of music therapy and beyond. I would like to thank OSCAR and the Undergraduate Research Scholars Program for their support and funding. I would also like to thank Dr. Karen Lee and Dr. Martin Wiener for their guidance during this project. Thank you for your time!

College of Science OSCAR

Developing Turn-On Fluorescent Tools for Cellular Imaging

Author(s): Amira Anwar, Eva-Maria Rudler

Mentor(s): Ozlem Dilek, Chemistry and Biochemistry

Abstract

The development of turn-on fluorescent tools is critical for advancing cellular imaging and improving disease diagnostics. Oxidative stress, caused by an
imbalance of reactive oxygen species (ROS), leads to carbonylation of biomolecules”a chemical process associated with cancer, neurodegenerative disorders, and diabetes. Detecting these modifications requires precise and robust tools. In this project, we synthesized small-molecule fluorophores capable of selectively targeting carbonyl groups (particularly biological aldehydes) in cells using click chemistry. These probes were designed with essential properties for effective imaging, including high stability, low toxicity, fast reaction kinetics, and favorable photophysical characteristics such as large Stokes shifts and reasonable quantum yields. By introducing these novel probes into cellular systems, we aim to visualize
carbonylation processes in various biological relevant systems (i.e.; cells, bioprinting). This work contributes to understanding oxidative stress mechanisms in human diseases, advancing diagnostics, and supporting the development of innovative tools for biomedical research.

Audio Transcript

Hello everyone, my name is Amira Anwar, and my URSP project is on Developing Turn-On Fluorescent Tools for Cellular Imaging. The objective of this research is to design small-molecule fluorophores that can selectively detect carbonylation in cells, a key marker of oxidative stress. We used click chemistry to develop probes that are stable, non-toxic, and exhibit strong fluorescence properties. This work aims to advance disease diagnostics and deepen our understanding of oxidative stress-related conditions such as cancer and diabetes.
Before diving into the project details, Id like to take a moment to thank my mentor, Dr. Ãzlem Dilek, my graduate student mentor Eva-Maria Rudler, and our entire lab group for their invaluable guidance and support throughout this research. Their input has been critical to the progress of this project. Now, a bit of background on the importance of this work. Oxidative stress occurs when theres an excess of reactive oxygen species, or ROS, in cells, which can damage biomolecules and lead to carbonylation. So here is an image that shows a normal cell and then the ROS damaging the cell and thus the resulting cell. This chemical process is closely linked to diseases like cancer, neurodegenerative disorders, and diabetes. Detecting carbonylation is crucial for early diagnosis and for tracking disease progression. In this project, we developed small-molecule fluorescent probes that can selectively label carbonyl groups in live cells. These probes are designed to work efficiently and safely in biological systems, enabling real-time imaging of oxidative stress processes. So, to achieve this, we synthesized hydrazine-based probes using click chemistry, which allows for fast and selective reactions under mild conditions. These probes need high stability, low toxiety, rapid kinetics, and large stokes shift. So, the probes were characterized for their absorption and emission properties, ensuring they are stable, non-toxic, and photophysically robust. We tested these probes using bioprinting scaffolds to observe their fluorescence “turn-on response when exposed to specific targets. This demonstrated their potential for real-world applications in biological imaging.Our results show that the probes were successfully synthesized and characterized. The fluorescence turn-on response observed in bioprinting scaffolds confirms the effectiveness of these probes in detecting oxidative stress markers. In conclusion, this work demonstrates the potential for using turn-on fluorescent probes to detect carbonylation processes in cells, contributing to the development of innovative diagnostic tools. This research advances our ability to study oxidative stress in disease progression, with applications that could lead to earlier diagnoses and better patient outcomes. For future work, the next steps include applying these probes to live-cell fluorescence imaging to evaluate their efficacy in biological systems. We also plan to extend their applications to tissue samples, 3D bioprinting, and design near-infrared probes for deeper imaging capabilities. This research lays the foundation for further development of fluorescent tools that can enhance our understanding of oxidative stress, its mechanisms, and its role in disease. Thank you for your attention!

College of Science OSCAR

Development of Predation Event Recorder (PERs) for Use in the Occoquan River

Author(s): Bryce Robertson

Mentor(s): Thomas Reid Nelson, Department of Environmental Science and Policy

Abstract

The construction and deployment of Predation Event Recorders (PERs) was undertaken to study predation events in the Occoquan River off the shore of the Potomac Science Center. The PERs were constructed using the Metrofruit Metro M4 microcontroller and a GPS Logger Shield for data collection, all housed within 3-inch PVC pipes with endcaps to ensure waterproofing. Key components included an action camera for visual data, a Reed Switch to indicate when bait had been taken, and a USB battery pack for power. All of this was weighed down with 5 pounds of lead shot (used for ballast), and steel washers used for magnetism for the Reed Switches. The bait was attached with fluorocarbon leads and magnetized with neodymium ring magnets. The PERs were to record predation events as well as the time and location of the events, which would offer insights into predator-prey dynamics and contribute to the broader understanding of riverine ecological processes.

Audio Transcript

Hello, everyone. My name is Bryce Robertson, and thank you for joining me today as I present the findings of my Undergrad Student and Research Project for Fall 2024 titled, The Development of Predation Event Recorders (PERS) for Use in the Occoquan River.” This project represents the cumulation of my efforts, guided by the mentorship of Dr. Thomas Reid Nelson to advance our understanding of predation dynamics within riverine ecosystems. The primary objective of this project was to design, construct, and deploy predation event recorders, purse to monitor and document predation events in the Occoquan River, a tributary of the Potomac River. These devices aim to capture crucial data about predator-prey interactions, including predation events timings as well as spatial distributions, thereby contributing to our broader understanding of ecological processes and freshwater systems. The content for the PERs was inspired by a previous study by Demetras et al in 2016, which you can see illustrated in the black and white image on the bottom left of the presentation. Building on this foundation, my goal is to adapt and refine the design to suit the specific condition of the Occoquan River. Each PER was constructed using a Metrofruit Metro m4 microcontroller paired with a GPS Logger shield for precise data collection. The entire ensemble was housed in three-inch PVC pipes cut into 30-inch sections and sealed with adhesive and a PVC encamped on the water-based side (the bottom), while the top end outside of the water was sealed with a flexible rubber end cap for easy removal so the Metro M4 could be retrieved, as well as allowing access to internal components. The PVC housings were specifically chosen for their durability and ability to withstand the riverine deployment. Each PER also had a couple of key components that were used. An action camera was used to capture visual data of the predation events. Two reed switches were used to detect when the bait was triggered, triggering the data recording, and another reed switch was used to record deployment of the PER a USB battery pack powered the device throughout its deployment and to maintain stability in the water, the pros were balanced with five pounds of lead shot. The reed switch functionally relied on the use of steel washers and neodymium ring magnets to detect bait removal while the bait itself was secured using fluorocarbon leads. During assembly, the Metro M4 microcontroller and GPS Logger shield were soldered together to establish robust electrical connections. These components enabled logging of timestamp data down to the millisecond, as well as GPS tracking and predation events. Careful attention was given to sealing the PVC tubes with all weather PVC adhesive ensuring watertight integrity while supporting the external mounting of the action camera and reed switches the use of Loctit Super glue. On this slide, you can see an internal view of the PER. The washers with the reed switch up top are for deployment, where we remove a magnet when it deploys and it tells us when we deployed. One at the very bottom, it’s a little blurry it’s hard to see, the second reed switch with five more washers with a neodymium ring magnet on the other side. When that magnet gets pulled out, it tells the predation occurred, and then it starts recording the data. Although the PERs not deployed during the study period. Plans to continue this research during summer 2025 will provide valuable insight into predator-prey interactions within the Occoquan River. Key species of interest include smallmouth bass, largemouth bass, flathead catfish, northern pike, and channel catfish, all apex or opportunistic predators. The data collected here will determine which species are the most frequent and responsible for predation events. Additionally, GPS tracking will enable the correlation of predation activity with specific riverine habitats, uncovering spatial trends that may inform future conservation and management strategies. Future research can build upon this foundation by exploring seasonal variations of predation, the effects of abiotic factors such as water temperature and flow rate, and potential competition between predator species. Such studies will not only enhance our understanding of predator-prey dynamics in the Occoquan River but also contribute to broader ecological knowledge applicable to other freshwater ecosystems. Thank you for your attention. I look forward to addressing any questions you may have about this exciting project.