College Center for Research & Fellowships
University of Chicago
The 2021 University of Chicago Undergraduate Research Symposium: Online Proceedings
Virtual Poster Session 2:
Physical Sciences Collegiate Division
The College, University of Chicago W. ccrf.uchicago.edu E. [email protected] College Center for Research & Fellowships
University of Chicago
The 2021 University of Chicago Undergraduate Research Symposium: Abstract
Learning from Artificial Intelligence Applied to a Pursuit-evasion Problem Based on Physical Laws Callum Welsh, 2nd-Year, Physics Mentor(s): Prof. Cheng Chin, Physics, James Franck Institute, Enrico Fermi Institute; Connor Fieweger, Chin Lab
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Modern physics research has identified artificial intelligence (AI) as a powerful tool for solving complex problems; one should ask, however, if such tools can lead to a deeper understanding of these problems, or equivalently if humans can learn from the solutions. To answer this question, we consider a simple pursuit-evasion game, “Cat and Rat”, where the “Cat” attempts to catch the “Rat” and the "Rat" attempts to escape. Based on simple physical laws, we construct a 2D simulator and employ the known effective guidance law of Augmented Proportional Navigation (APN) as the baseline strategy for the Cat. We then apply a Cartesian Genetic Programming (CGP) AI algorithm to control the Rat to attempt escape. We show that CGP was consistently able to counteract APN for a wide range of parameters. More importantly, we note that CGP offers human-readable solution output. To this end, we demonstrate how the CGP output allows us to realize a new Rat strategy and to improve our performance in counteracting APN. We argue that this ability to learn from AI is a primary benefit of CGP and that this learning is critical to the use of AI in physics.
The College, University of Chicago W. ccrf.uchicago.edu E. [email protected] College Center for Research & Fellowships
University of Chicago
The 2021 University of Chicago Undergraduate Research Symposium: Abstract
Assessing the X-ray Evolution of Galactic and Magellanic Cloud Supernova Remnants Chris Albert, 3rd-Year, Astrophysics and Mathematics Mentor(s): Prof. Vikram Dwarkadas, Astronomy and Astrophysics
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This project presents an X-ray study of the supernova remnant (SNR) population within our Galaxy and the Magellanic clouds (LMC and SMC). A more accurate data set exists for the latter due to better distance determination, while Galactic SNR properties have larger error bars due to uncertainties in distances. We study the relationship between the X-ray luminosity and remnant radius, limiting our sample to remnants for which reasonably well-defined measurements of total X-ray luminosity and size exist. We examine various trends in the data, taking into account estimated age and ambient densities given in the literature. We demonstrate how the X-ray luminosity to size relationship can sometimes help to constrain distance estimates, or reduce the error bars on derived properties. We assess the difference between the Galactic and LMC SNR distribution and find it can be explained by densities in the LMC being on average 30% that in the Galaxy. This agrees with the densities around X-ray SNRs in each galaxy. Our results show agreement between observed X-ray luminosities and predictions using a Sedov-Taylor solution. They offer a framework that may allow for convenient estimation of the evolutionary state and physical properties.
The College, University of Chicago W. ccrf.uchicago.edu E. [email protected] College Center for Research & Fellowships
University of Chicago
The 2021 University of Chicago Undergraduate Research Symposium: Abstract
Investigation of Solvation Effects of Electrolyte on Electrocatalytic CO2 Reduction Reaction in Organic Media Christopher Birch, 4th-Year, Chemistry, Neuroscience Mentor(s): Prof. Chibueze Amanchukqu, Pritzker School of Molecular Engineering; Reginaldo Jose Gomes Neto, Amanchukqu Group
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Electrocatalytic CO2 reduction shows potential for conversion of CO2 to industrially useful chemical compounds, such as alcohols, carbon monoxide, and alkenes. However, the field has focused on aqueous media for these reactions, limiting high Faradaic efficiency to desired products due to a competing hydrogen evolution reaction (HER). Research on this reaction in organic solvents is in its early stages and may eliminate the competing HER. By investigating the solvation mechanics of this reaction in organic media, a more efficient reaction may become possible, as indicated by previous work showing that a minimally solvated cation may lead to desirable intermediates for this reaction. Nuclear magnetic resonance (NMR) was used to investigate solvation environment of the electrolytes in a nonaqueous medium. These results were compared to cyclic voltammetry (CV) and double layer capacitance (Cdl) values for the CO2RR against metallic Au and Cu as working electrodes. The CO2RR electrochemical performance was also correlated with intrinsic properties of each electrolyte solution, such as conductivity, solvent Gutmann donor and acceptor numbers, and cation alkyl chain length. The resulting NMR data analysis showed minimal evidence of differing solvation of the electrolyte cation regardless of the anion present, which shows that properties of the electrolyte anion are not influential on the solvation environment in DMSO. Because of this lacking impact of the anion on solvation behavior and CO2RR electrochemical performance, the next step to investigating the optimal environment for the CO2 reduction reaction in organic media is comparing organic solvents. A preferential solvation environment may improve experimental data and product distribution without introducing competing HER. From there, the pathway will be opened to explore further electrochemical properties to move this technique toward industrial scale conversion of CO2 to societally beneficial products.
The College, University of Chicago W. ccrf.uchicago.edu E. [email protected] College Center for Research & Fellowships
University of Chicago
The 2021 University of Chicago Undergraduate Research Symposium: Abstract
Documentation and Website Construction for a New Custom Electronics System at the ATLAS Experiment Daniel Paraizo, 3rd-Year, Physics & Mathematics Mentor(s): Prof. David Miller, Physics
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As part of the Phase-I upgrade for the ATLAS experiment at the Large Hadron Collider (LHC), a new custom electronic system called the Global Feature Extraction (gFEX) module is being developed and tested. The gFEX unit is a Level-1 trigger detector that uses jet algorithms to select for large-radius jets - essentially a collection of final state particles that comprise a single parent object - typical of particles such as top quarks, W/Z bosons, and the Higgs boson. Some of the key upgrades the gFEX unit provides is that it will considerably enhance the selectivity of the Level-1 ATLAS trigger and will be capable of processing the entire calorimeter (a specific type of detector found at ATLAS) on a single electronics board, all while allowing for local event-by-event pileup (noise) suppression. The ATLAS Phase-I upgrade is a complex and ongoing series of updates involving several new systems, including the gFEX unit, all of which must work together to ensure smooth functioning of the ATLAS experiment at the LHC. Thus, an important task is the documentation and internal communication of the most up-to-date technical design and details of the gFEX unit to the various teams working on the ATLAS Phase-I upgrade. Additionally, it is essential to publicize ATLAS-approved information on the gFEX project to a wider audience in the physics community. One way to accomplish this is through a central gFEX website that collects and presents the most relevant information for quick and easy reference. The content of the webpage will be pulled from numerous GitLab repositories, Twiki’s, and CERN’s version of a document control system called EDMS. Aspects of website coding will also be presented, and future work on the webpage, such as ease-of-updating, will be explored.
The College, University of Chicago W. ccrf.uchicago.edu E. [email protected] College Center for Research & Fellowships
University of Chicago
The 2021 University of Chicago Undergraduate Research Symposium: Abstract
Calibration of Lithium-6 Atom Numbers in a Magneto-Optical Trap with Absorption Imaging Huiting Liu, 3rd-Year, Physics & Philosophy and Allied Fields Mentor(s): Prof. Johannes Hecker Denschlag, Institute for Quantum Matter, Ulm University, Germany
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The size and shape of an atom cloud and the distribution of atoms inside are some of the most important observables that we can access in a cold atom experiment. Images of the atom cloud are often the exclusive primary data from which such information can be extracted. One widely used imaging technique is absorption imaging, where a camera records the shadow cast by the atoms when a laser is shone into the camera through the atom cloud. However, several additional effects can complicate the imaging process and make one extract wrong atom numbers from the images. Under laser illumination, the atoms can accelerate and have their energy levels slightly shifted, leading to a misrepresentation of atom distribution on the image. Saturation effects might also cause the atom number recorded on an image to be lower than actual. Conventional imaging processing techniques does not retain the necessary information to account for such systematic errors in the atom numbers. In this research, we improve the imaging analysis procedure with the help of a more sophisticated analysis which, for instance, takes into account the saturation effects. This analysis procedure improves the quality of information extracted from the atom cloud in our Lithium-6 experiment. It might also be useful for a wider range of cold atom setups where different atomic elements are used.
The College, University of Chicago W. ccrf.uchicago.edu E. [email protected] College Center for Research & Fellowships
University of Chicago
The 2021 University of Chicago Undergraduate Research Symposium: Abstract
Using Photo-switchable Dyes for 4D Localization of the Gamma Ray Compton Scatters in a Whole-Body Positron Emission Tomography Detector João Shida, 3rd-Year, Molecular Engineering & Physics Mentor(s): Prof. Henry Frisch, Physics, Enrico Fermi Institute; Patrick La Riviere, Radiology; Allison Squires, Pritzker School of Molecular Engineering; Viresh Rawal, Chemistry
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We propose a technique to use switchable fluorescent molecules to image localized energy depositions in a whole-body Positron Emission Tomography (PET) scanner. A gamma ray scatters multiple times in an organic solvent and generates Compton electrons. The electrons deposit energy in the organic solvent proportional to the energy of the scatter. The excitations transfer energy to initially non-fluorescent switching molecules and activate them into a fluorescent configuration. The activated molecules can be repeatedly excited by optical photons, yielding many fluorescence photons each before being reset to the inactive configuration. This technique would be applied to generate high-resolution images of gamma scattering events inside scintillator-filled modules arranged in a cylinder around the patient. The time of each Compton scatter is determined using prompt scintillation light detected by a photodetector with time resolution on the order of 50 ps. Selective illumination of the module from various angles would allow iterative refinement of the electron paths and then the detailed structure of the event. Combined with precise temporal resolution, the positron annihilation in the patient between opposing modules can be reconstructed to within a thin needle-like region of total volume on the order of 1 mm3. The number of activated molecules takes a role analogous to the light yield of a conventional scintillator, providing a measurement of the energy. The geometry and energies of the successive Compton scatters can be used to constrain and reject in-patient scattering background. There exists at least one class of well-studied molecules which may be capable of meeting the requirements of the technique.
The College, University of Chicago W. ccrf.uchicago.edu E. [email protected] College Center for Research & Fellowships
University of Chicago
The 2021 University of Chicago Undergraduate Research Symposium: Abstract
MAROON-X’s Exposure Time Calculator Jorge A. Sanchez, 4th-Year, Astronomy and Astrophysics Mentor(s): Prof. Jacob Bean, Astronomy and Astrophysics; Prof. Andreas Seifahrt, Astronomy and Astrophysics
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We report on the completion of the new Exposure Time Calculator and graphical interface for MAROON-X. MAROON-X is a radial velocity spectrograph designed to detect Earth sized planets orbiting mid to late M dwarf stars. Now in regular operation at the Gemini North telescope in Hawaii, those who plan on using MAROON-X now have access to its new Exposure Time Calculator, a graphical interface designed to output useful information when collecting data with the instrument. By inputting a number of fields corresponding to the user’s observation conditions, such as exposure time, magnitude and spectral type, the Exposure Time Calculator will generate the predictive radial velocity measurement precision for the instrument. A fully interactive web-based tool, MAROON-X’s ETC provides real time updates to fit specific observation conditions, along with the functionality of allowing users to save all generated plots for later use.
The College, University of Chicago W. ccrf.uchicago.edu E. [email protected] College Center for Research & Fellowships
University of Chicago
The 2021 University of Chicago Undergraduate Research Symposium: Abstract
Biocompatible and Nano-enabled Technologies for Biological Modulation Kavita Parekh, 3rd-Year, Biological Chemistry Mentor(s): Prof. Bozhi Tian, Chemistry
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The creation of biocompatible nanoscale devices for biological modulation of cells and tissues possess the potential for tremendous impact on a variety of technologies, such as those in medicine. Typical medical devices and therapies tend to be microscale, comprised of non-biocompatible materials, and broadly targeted, resulting in imprecise treatments and adverse effects such as chronic immune response and tissue damage. The development of nano-enabled and biocompatible technologies – ranging from biodegradable nanoparticles for localized drug delivery to transient electronic devices for stimulation therapy to engineered biofilms with applications to nanomedicine – will continue to enable the advent of personalized medicine. This presentation discusses recent research into this frontier through synthesis and biocompatibility considerations before delving into latest advancements for cardiac, neural, and microbial modulation. Using these examples as a basis, future research directions in this field are described with an emphasis on explorations into biocompatibility for neural modulatory devices.
The College, University of Chicago W. ccrf.uchicago.edu E. [email protected] College Center for Research & Fellowships
University of Chicago
The 2021 University of Chicago Undergraduate Research Symposium: Abstract
Optical Control of Levitated Particles in a Thermophoretic Trap Kelsey Gilchrist, 3rd-Year, Physics Huiting Liu, 3rd-Year, Physics & Philosophy and Allied Fields Mentor(s): Prof. Cheng Chin, Physics
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We study the dynamics of levitated particles under illumination by a laser. Microspheres ranging from 10 to 50 μm in diameter are levitated and trapped in a thermophoretic force field generated in a vacuum chamber with air pressures between 4 and 15 Torr. The laser heats up and creates a temperature differential in the levitated particles. Momentum exchange with the surrounding gas drives the illuminated particles either in the direction of laser propagation (positive photophoresis) or opposite the direction of laser propagation (negative photophoresis). We report observations of both positive and negative photophoretic forces on levitated particles. To understand our experimental results vis-à-vis existing models of photophoresis, we simulate the radiation field and temperature distribution in levitated spheres to to obtain quantitative predictions of the photophoretic and thermophoretic forces. This study of illumination-induced dynamics is a necessary first step towards optical control of levitated particles, which will find applications in studying micron-scale physics and force fields in a microgravity environment.
The College, University of Chicago W. ccrf.uchicago.edu E. [email protected] College Center for Research & Fellowships
University of Chicago
The 2021 University of Chicago Undergraduate Research Symposium: Abstract
Topological Polarization of Odd Elastic Media Livia Guttieres, 2nd-Year, Physics & Mathematics Mentor(s): Prof. Vincenzo Vitelli, Physics (Topological Mechanics)
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Much of what we know about the mechanics of solid materials can be ascertained by a surprisingly simple model: a collection of masses and Hookean springs. As one learns in first year physics, a Hookean spring exerts a tension in response to elongation or compression. Here, we ask how do the mechanics of solids change when the springs exert torques instead of tensions? In particular, it is known that geometric and topological properties of Hookean mass spring networks can predict features such as localized softness or rigidity. In this presentation, we will discuss how to generalize these ideas when the forces are transverse rather than longitudinal. Understanding the role of transverse forces in mechanical rigidity will shed light on the mechanical principles at play in complex media ranging from living organism to robotic materials.
The College, University of Chicago W. ccrf.uchicago.edu E. [email protected] College Center for Research & Fellowships
University of Chicago
The 2021 University of Chicago Undergraduate Research Symposium: Abstract
Identifying Globular Cluster Populations in Low Surface-Brightness Galaxies Elizabeth (Louise) Gagnon, 3rd-Year, Astronomy and Astrophysics Mentor(s): Prof. Alex Drlica-Wagner, Astronomy and Astrophysics, Fermi National Accelerator Laboratory
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My research concerns low surface-brightness galaxies (LSBGs). An LSBG is defined as a diffuse galaxy whose surface brightness is fainter than the ambient night sky by at least one magnitude. I specifically investigated LSBGs containing populations of objects that could potentially be globular clusters. My goal was to identify and analyze such LSBGs in the DES Year 3 data—theoretically, by measuring the luminosities of their globular cluster populations, we can calculate the distance to the host galaxies, allowing us to gain a better understanding of the cosmic distribution of LSBGs. From the DES Y3 LSBG data, I selected the largest LSBGs with the highest densities of objects masked by Source Extractor in their radius. This was a group of 68 galaxies. I then wanted to determine which of the objects around these galaxies were globular clusters, which was done by analyzing their properties and applying a cut based on their SPREAD_MODEL and MAG_AUTO values. I selected a group of nine LSBGs with the greatest number density of surrounding candidate globular clusters and hope to potentially submit a proposal for further imaging of these galaxies.
The College, University of Chicago W. ccrf.uchicago.edu E. [email protected] College Center for Research & Fellowships
University of Chicago
The 2021 University of Chicago Undergraduate Research Symposium: Abstract
Construction and Characterization of Narrow Linewidth Cat-eye Diode Lasers Lucas Baralt Nazario, 4th-Year, Physics, Romance Languages and Literatures Connor Fieweger, Recent Alum, Physics Mentor(s): Prof. Cheng Chin, Physics, James Frank Institute, Enrico Fermi Institute; Jonathan Trisnadi, Chin Lab; Jiamei Zhang, Chin Lab
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Laser cooling and imaging of neutral atoms rely on the absorption of photons whose frequency is in resonance with the atoms. The cooling efficiency and the imaging resolution are usually limited by the spectral purity of the light utilized to excite the atoms. Consequently, it is of great interest to develop narrow linewidth, ultra-stable laser sources in order to perform high fidelity experiments. In this poster, I will describe the construction of narrow linewidth 852 nm external cavity diode lasers (ECDLs) in the cat-eye configuration, which will be used for degenerate Raman-sideband cooling and fluorescence imaging of cesium atoms in the Quantum Matter Synthesizer experiment. I first discuss the cat-eye geometry and its advantages over other ECDL configurations due to an increased mechanical stability. I then consider different manners in which the cat-eye geometry can be implemented and present cat-eye lasers that were built. Their behavior is characterized and the influence of optical and electronic feedback on laser stability and linewidth is discussed. We observe a strong correlation between laser feedback and spectral linewidth and report narrow linewidths of less than 70 kHz and power outputs of up to 70 mW. Finally, we consider linewidth and output power limitations, how we can improve them and future experimental applications of the lasers.
The College, University of Chicago W. ccrf.uchicago.edu E. [email protected] College Center for Research & Fellowships
University of Chicago
The 2021 University of Chicago Undergraduate Research Symposium: Abstract
A Precision Measurement of the K Long to Three Neutral Pion Dalitz Decay Branching Ratio Michael Farrington, 3rd-Year, Physics Mentor(s): Prof. Yau Wah, Physics, Enrico Fermi Institute
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The KOTO Experiment has collected 1.8 million events of neutral Kaon to three neutral Pion decay (denoted 3 ) over the course of recent data-taking runs which has yielded a large amount of decay data that 0is virtually background-free, offering a unique opportunity to study Dalitz decay. 𝐿𝐿 Neutral0 Pions𝐾𝐾 → typically𝜋𝜋 decay through the electromagnetic force into two photons in (98.8230 ±0.034) % of𝜋𝜋 decays but can also undergo Dalitz decay where the Pion decays into a photon and an𝜋𝜋 electron- positron pair. The branching ratio of this decay is calculable within quantum electrodynamics and has been measured to be (1.174 ±0.035) % which has an uncertainty of three percent of the value of the measurement. The KOTO decay dataset can be used to make a more precise measurement of the Dalitz branching ratio with an0 uncertainty of about one percent. The E14 KOTO detector provides an excellent means of identifying𝜋𝜋 Dalitz decay with a 2576 crystal CsI calorimeter covered by a plastic scintillator charged particle detector.0 To measure the Dalitz Decay branching ratio I am studying decay events with six hits on the𝜋𝜋 calorimeter and energy0 deposits on the charged particle detector and comparing them with a dataset of simulated 3 𝜋𝜋 decay events created using Geant4. 0 𝐾𝐾𝐿𝐿 → 𝜋𝜋
The College, University of Chicago W. ccrf.uchicago.edu E. [email protected] College Center for Research & Fellowships
University of Chicago
The 2021 University of Chicago Undergraduate Research Symposium: Abstract
Extended Supersymmetry from Superspace Fangxin (Sam) Li, 3rd-Year, Physics & Mathematics Mentor(s): Prof. Savdeep S. Sethi, Physics, Enrico Fermi Institute, Kadanoff Center for Theoretical Physics
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Supersymmetry, the symmetry between bosons and fermions, plays an essential role in our modern understanding of the universe. It is usually desirable to formulate a supersymmetric theory in the superspace formalism because the symmetry generators can be represented as “geometric symmetries” of superspace. However, models with extended supersymmetry, which attract much attention in the study of string theory, require additional constraints on superspace. By deriving the required constraints on the Lagrangian couplings, we develop a superspace formulation of quantum mechanical gauge theory with sixteen supersymmetries.
The College, University of Chicago W. ccrf.uchicago.edu E. [email protected] College Center for Research & Fellowships
University of Chicago
The 2021 University of Chicago Undergraduate Research Symposium: Abstract
Utilizing Polymer Soft Confinement for Novel De-icing Surfaces Wilson Turner, 2nd-Year, Molecular Engineering & Chemistry, Polymeric and Soft Materials Mentor(s): Prof. Steven J. Sibener, Chemistry, James Franck Institute
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The preparation of sturdy, effective anti-icing surfaces is important in many industries such as aviation. Ice formation on aircraft wings, for instance, can cause a 25% increase in drag and 90% reduction in lift, while ice accretion on wind turbines can decrease annual energy production by 17%. Despite this pressing technological need, there is limited understanding behind the nucleation processes of ice on surfaces. Recent computational studies suggested that the soft confinement of water into nanoscale domains enables liquid water to exist at the surface well below freezing temperatures, significantly reducing any ice adhesion. My goal is to experimentally probe this further though the use of hygroscopic polymer coatings. Specifically, I plan to understand how soft confinement impacts ice nucleation and growth and to develop novel experimental techniques to probe the buried polymer-ice interface. First, I’ve been focusing on creating different polymer surfaces with long range order through the application of Directed Self- Assembly (DSA), a physical phenomenon in which block-copolymers tend to self-organize into ordered arrays of monomers when annealed onto a surface. Herein, we propose the utilization of DSA by annealing and etching standing cylinder-phase Poly(styrene-b-methyl methacrylate) to create a surface with specifically tailored anti-icing properties. My initial results demonstrate the success of etching with ultraviolet radiation to create an ordered nanoporous surface. Utilizing an advanced cooling stage with humidity control, my goal is to then measure the effects of soft polymer confinement by calculating surface free energy and adhesive force constants. Understanding the role of soft confinement on the heterogeneous catalysis of ice formation will help elucidate how to properly control ice growth and adhesion at the nanoscale and ultimately, when combined with our collaborator’s simulations, will lead to a dramatically improved understanding of how roughness and liquidity at interfaces impacts ice adhesion and detachment.
The College, University of Chicago W. ccrf.uchicago.edu E. [email protected] College Center for Research & Fellowships
University of Chicago
The 2021 University of Chicago Undergraduate Research Symposium: Abstract
Evaluation of Platforms for Selection of Highly Functionalized Cyclic Peptides Yuhan (Steven) Xu, 3rd-Year, Biological Chemistry & Mathematics Mentor(s): Prof. Weixin Tang, Chemistry
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Ribosomally-synthesized and post-translationally modified peptides (RiPPs) are a rich group of natural products with great therapeutic potentials. Post-translational modifications (PTMs) endow RiPPs with structural rigidity and resistance to cellular degradation, and the PTM enzymes are often promiscuous so that it is possible to diversify the substrate peptide without threatening the PTMs. Because RiPPs are genetically encoded, library construction and screening can be carried out in a high-throughput fashion. Based on these features, we envisioned a method for drug discovery that includes the construction of a diverse library of randomized RiPPs and a competent selection platform to screen for properties of therapeutic relevance, such as protein binding and protein-protein interaction inhibition. Using ProcA2.8 and its variant XY3-3, we have tested two bacterial two-hybrid systems as selection platforms. While ProcA2.8 does not interact with the UEV domain of human Tsg101 protein, XY3-3 binds to UEV and inhibits the p6-UEV protein-protein interaction. By quantitatively characterizing ProcA2.8 and XY3-3 for inhibiting the p6 and UEV interaction, we were able to evaluate the fitness of these platforms for selections of protein binders or protein-protein interaction inhibitors. We chose the platform with a luminescence readout for our following selections. In the future, we will modify and optimize the platform to screen for highly functionalized peptides with therapeutic benefits. In particular, the latest genome mining efforts of the metagenomes of the human gut microbiota have provided us a great amount of novel RiPPs that have the potential to be adapted for library construction and screening. The screening process provides invaluable insights into the enormous potential of RiPPs in drug discoveries.
The College, University of Chicago W. ccrf.uchicago.edu E. [email protected] College Center for Research & Fellowships
University of Chicago
The 2021 University of Chicago Undergraduate Research Symposium: Abstract
Noise2Astro--Astronomical Image Denoising With Self-Supervised Neural Networks Yunchong Zhang, 3rd-Year, Astrophysics Mentor(s): Dr. Brian Nord, Astronomy and Astrophysics, Kavli Institute for Cosmological Physics, Fermi National Accelerator Laboratory
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In observational astronomy, weather, satellites, high-energy particles, and noise of various kinds obscure the primary signal of interest. Large-scale astronomical surveys are growing in size, precision, and complexity, which will incur more information in images, and this information includes more potential sources of noise. Conventional algorithmic tools for image de-noising are challenged to handle efficiently the huge workload of the task of image reduction Therefore, developing automated tools such as convolutional neural networks (CNN) for denoising has become one of the most promising methods. However, current supervised learning algorithms require prior knowledge of the morphology of the target objects, which significantly limits the applicability of denoising neural networks. Our research project utilizes a self-supervised algorithm, which does not require any prior knowledge of the signal, to develop a framework for denoising astronomical images. We performed experiments on our self-supervised algorithm with several neural network architecture of different variety and complexity, testing our overall framework with simulated noisy images of different noise realization. We examined our results by comparing them with the pristine ground-truth (noiseless) images. In our experiments, despite insufficient accuracy in recovering the amplitude of the object signal, our algorithm demonstrates satisfying capability in recovering morphological characteristics of the simulated objects. We conclude that our self-supervised algorithm may only have limited application in the signal modeling for catalogs of large astronomical surveys. However, it may contribute to tasks that involve processing astronomical images with complicated morphologies such as the search for gravitational lensing.
The College, University of Chicago W. ccrf.uchicago.edu E. [email protected] College Center for Research & Fellowships
University of Chicago
The 2021 University of Chicago Undergraduate Research Symposium: Abstract
Structure-Property Relations in Amorphous Carbon with Quantum Molecular Dynamics Yunxiang (Tony) Song, 3rd-Year, Physics, Computer Science Mentor(s): Prof. Giulia Galli, Pritzker School of Molecular Engineering; Dr. Arpan Kundu, Pritzker School of Molecular Engineering
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Amorphous carbon (a-C) is a common form of carbon material with broad ranging applications in industry. Computer simulations of a-C enable a theoretical investigation of its structural and electronic properties. One such property is the energy difference between the highest occupied molecular orbital and the lowest unoccupied molecular orbital. This difference determines the minimum energy required for an electronic excitation, and it is modulated by electron interactions with the lattice at finite temperatures. This modulation is referred to as the band gap renormalization. Accurate determination of the band gap renormalization in the low-temperature quantum regime requires computationally expensive path-integral molecular dynamics methods to fully address the effects of nuclear quantum motion. The high structural disorder of a-C gives rise to different amounts of band gap renormalization depending on the chosen sample. Distinct structural signatures of such samples motivate the search for suitable descriptors of the band gap renormalization, which can be used, both to predict the renormalization without the need for expensive simulations, and to offer a new window into probing the renormalization experimentally. In this work, we determine the zero-point band gap renormalizations of seven a-C samples at 3.25 / using molecular dynamics with quantum thermostat where forces are obtained by solving Kohn-Sham 3equations within generalized gradient approximations. We then correlate structural properties𝑔𝑔 𝑐𝑐 with𝑚𝑚 the band gap renormalizations, forming the basis for constructing predictive models. The construction of such models will allow for the efficient computational and experimental determination of the zero-point band gap renormalization in a-C, important for the development of a-C based semi-conductor devices of the future.
The College, University of Chicago W. ccrf.uchicago.edu E. [email protected]