2019 Abstract Book
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Student-Faculty Programs 2019 Student Abstract Book STUDENT-FACULTY PROGRAMS 2019 Abstract Book This document contains the abstracts of the research projects conducted by students in all programs coordinated by Caltech’s Student-Faculty Programs Office for the summer of 2019. Table of Contents Summer Undergraduate Research Fellowships (SURF) 1 WAVE Fellows Program 101 Amgen Scholars Program 111 Laser Interferometer Gravitational-Wave Observatory (LIGO) 117 Jet Propulsion Laboratory 125 SURF S U R F S U R F Functionalization of Shape Memory Polymers With Gold Nanoparticles Sébastien Abadi Mentors: Julia Greer and Luizetta Navrazhnykh Shape changing materials are important for some biomedical devices, like neuronal probes, as a compact device can be inserted and then expanded when properly positioned, thereby reducing damage to tissue. Thermal shape memory polymers (tSMPs) can be programmed so that a temperature increase above its glass transition triggers such a shape change to occur. The objective of this study was the remote activation of this transition on a microscale tSMP. To do so, the tSMP was functionalized with gold nanoparticles (AuNPs), which have high absorbance at 532 nm due to localized surface plasmon resonance. A laser of this wavelength could therefore heat the attached tSMP, remotely triggering recovery. The tSMP in question is a benzyl-methacrylate based polymer that has been used to fabricate microscale shape memory structures, and contains BOC-protected amine groups. These amines were deprotected and then thiolated using S-acetylmercaptosuccinic anhydride, as thiols will bind AuNPs. These AuNPs can then be detected with solid-state UV-vis spectroscopy to confirm attachment. Moving forward, a focused 532nm laser beam could be used to activate individual microscale structures and perhaps control the sequence of SMP recovery. Design and Creation of a Multirotor Testbed for Use With Autonomous Swarms Kasey Adams Mentors: Soon-Jo Chung and Kyunam Kim In the emerging field of swarm robotics, algorithms for motion planning, collision avoidance, and goal-oriented task assignment are being developed to create distributed, robust systems. To test these algorithms, a robust and durable testbed is imperative. A quadcopter pair was developed to complement the previous generation as a dynamic test bed. The system supports various payload masses and was designed for longevity. The new generation drastically improved on the design of the previous generation, providing more modularity and greater ease of access/repair. In the new generation of agents, we replaced the previous NeuMotor 2025 Outrunner motors with the NeuMotor 4606 Outrunner motors. The new motors showed higher efficiency, lower current draw, and higher thrust at the given hover RPM. In addition to this, we increased the size of our LIPO battery from 4S to 6S. These two changes were the most significant changes that impacted the performance of the new generation, which showed longer flight times (10:11 when loaded with 1141g as opposed to ~10min when unloaded for the previous generation) and a higher max payload (1983g when stopped testing versus 1.4kg max payload for older generation). Illusions in Extreme Peripheral Vision Sara Adams Mentors: Shinsuke Shimojo, Daw-An Wu, and Takashi Suegami Despite a significantly lower density of photoreceptors in regions of the retina representing extreme peripheral vision, our peripheral vision appears clear. Thus, some of what we see in this region must be illusory; that is, the perception is not fully explained by direct retinal input. In particular, we found that motion perception is not uniform between the fovea and the periphery. Depending on the condition, a flickering peripheral stimulus may be perceived to be either faster or slower than an identical stimulus in the fovea. The direction of this perceptual change is significantly affected by the flicker frequency of the stimulus. Chalcone Derivatives and Their Efficacy Against Castration Resistant Prostate Cancer Arushi Agarwal Mentors: Tanya Stoyanova, Meghan Rice, and David Van Valen Prostate cancer is the most common non-cutaneous cancer in men in the United States. Although there are hormone-based treatments for prostate cancer, in many cases, the cancers develop an incurable resistance—leading to castration resistant prostate cancer (CRPC). The Malhotra Lab at the Department of Radiation Oncology at Stanford University developed a compound library of non-hormonal therapies based on natural product chalcones targeting other characteristics of cancer, such as glycolysis (Rice and Kumar et al. unpublished). In the Stoyanova lab, we applied nine of the chalcone compounds and tested their efficacy for the treatment of prostate cancer in vitro. To identify compounds with low toxicity and high efficacy, we first evaluated the half-inhibitory concentration (IC50) of each drug. The IC50 values ranged from 800nM to 20µM. Using the IC50 concentrations, we tested the effects of each drug on colony formation, cell proliferation, cell migration, and cell invasion of DU145, 22RV1, and C4-2 CRPC prostate cancer cell lines. Several compounds had strong antiproliferative abilities which we will translate to preclinical studies with pharmacokinetic analysis and toxicity analysis in vivo. This project identifies chalcone derivatives with potential as novel prostate cancer therapeutics. 1 Angular Calibration of the BICEP Array Receivers Using Far Field Beam Map Characterization Shubh Agrawal Mentors: Jamie Bock and Alessandro Schillaci The BICEP Array is the latest generation of instruments of the BICEP Keck Collaboration for Cosmic Microwave Background polarimetric measurements. It comprises four 550 mm telescopes observing between 30 to 270 GHz, aiming to generate sensitive CMB polarization maps for the detection of B-mode polarization signal, which would be the first direct evidence of inflationary gravitational waves. My project focused on designing, constructing, and implementing a movable configuration allowing for full optical far-field characterization of the receivers, using a chopped thermal hot source. A structure for orienting a flat aluminum honeycomb mirror panel, delineated using ray tracing applications of Zemax, was designed and tested for stability using SolidWorks and assembled after machining. The motion was made controllable and programmable by implementing code in C. A Python interface was created to generate beam maps by allowing step motions and data acquisition. Zemax was also used to analytically compare diffraction energies at receiver in the far-field or quasi-far-field. Further work over summer and academic year would involve conducting far-field beam mapping for the current and future 30/40GHz receivers and result in generating fractional differential plots against two-dimensional Gaussian fits to characterize the optical performance of the BICEP Array. Investigating the Functional Significance of O-GlcNAc Transferase Substrate/Interactor Networks Rita Aksenfeld Mentors: Linda Hsieh-Wilson and John Thompson O-linked β-N-acetylglucosamine glycosylation (O-GlcNAcylation) is a dynamic, inducible post-translational modification (PTM) of thousands of intracellular proteins. There are only two enzymes responsible for O-GlcNAc cycling in higher eukaryotes, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA), which catalyze addition and removal, respectively. We hypothesized that constructing OGT substrate/interactor networks could serve as a useful foundation for understanding the functions of O-GlcNAcylation. Moreover, this approach might reveal novel insights into how OGT is able to coordinate the specific modification of thousands of proteins in response to individual stimuli. Here, we first sought to validate interactor-substrate relationships suggested by these networks. Specifically, we found that knockdown of OGT interacting proteins was sufficient to disrupt O-GlcNAcylation of non-interacting OGT substrates. This finding suggests that association between OGT and its interactors may allow OGT to engage different sets of substrates in different contexts. Finally, we investigate whether modulating global O-GlcNAcylation can affect peroxisome biogenesis and function, a potentially novel role for O-GlcNAcylation revealed by our network. Together, these studies demonstrate that our networking approach highlights functional connections between OGT interactors and substrates. Identifying the Effects of Solar Heat on the Redness of KBOs Alya Al-Kibbi Mentor: Michael E. Brown The Jupiter Trojan asteroids and distant KBOs exhibit bimodality in their g-i redness, with Trojan peak values being ~0.3 magnitudes less red than KBO counterparts. The standing hypothesis is that as KBOs approach the Sun and get warmer, heat mutes their redness. Our objective is to determine the heliocentric distance at which high eccentricity KBOs transition from typical KBO redness distributions to distributions resembling those of Trojan asteroids. We collected data from a sample of 28 KBOs with high eccentricities and a range of perihelion distances to link the Trojans and distant KBOs. Each object was imaged in the g’ and i’ filters of the WASP instrument on the Hale 200inch telescope. Magnitudes of objects in both filters were combined to calculate their g-i color, which allows for comparison with other solar system populations. Results show our sample KBOs exhibiting redness consistent with predictions: those with lower perihelia have g-i colors near the mean values for the