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The University of San Francisco

2020

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Articles 31 - 46 of 46

Full-Text Articles in Physical Sciences and Mathematics

Synthesis Of Sultams From Vinyl Aziridines And 1,4-Diazabicyclo[2.2.2]Octane Bis(Sulfur Dioxide), John Gandara May 2020

Synthesis Of Sultams From Vinyl Aziridines And 1,4-Diazabicyclo[2.2.2]Octane Bis(Sulfur Dioxide), John Gandara

Creative Activity and Research Day - CARD

Sultams are an important functional group found in medicinal compounds with anticancer and enzyme inhibition activity. Traditional methods for sultam synthesis often require harsh conditions and have limited substrate scope. This research focuses on developing a novel methodology for the production of sultams using DABSO (1,4-diazabicyclo[2.2.2]octane bis(sulfur dioxide)) and vinylic aziridines. Our synthetic strategy starts with a Corey-Chaykovsky epoxidation of cinnamaldehyde, followed by an epoxide-opening using sodium azide. The final vinylic aziridine is synthesized by mesylation and Staudinger reduction of the resulting azido alcohol. Reaction of this vinyl aziridine with DABSO may provide a new strategy for synthesizing sultams. Following …

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Determining The Mechanical Properties Of The E. Coli Methionine Transporter, Kha Andy Tran May 2020

Determining The Mechanical Properties Of The E. Coli Methionine Transporter, Kha Andy Tran

Creative Activity and Research Day - CARD

Adenosine Triphosphate Binding Cassette (ABC) transporters constitute a superfamily of active transporters embedded in the cellular membrane. They consist of two highly conserved nucleotide-binding subunits which bind and hydrolyze ATP, and two diverse transmembrane subunits which provide a pathway for the substrate to pass through the membrane. ABC transporters serve a broad range of vital functions. Various conditions like cystic fibrosis and Stargardt disease are caused by defunct ABC transporters, and certain medical complications like antibiotic drug resistance are linked to promiscuous ABC transporters. Despite the importance of these transporters in crucial biological processes, the mechanisms of many transporters are …

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Extraction Of Thyme Leaves And Analysis Of Antibacterial Properties: An Adaptation For Usf Analytical Chemistry Lab Course, Kevin Do, Matthew Barnett May 2020

Extraction Of Thyme Leaves And Analysis Of Antibacterial Properties: An Adaptation For Usf Analytical Chemistry Lab Course, Kevin Do, Matthew Barnett

Creative Activity and Research Day - CARD

We streamlined and adapted the thyme leaf extraction and analysis experiment developed by Purcell et al. at the University of California, Berkeley for the analytical chemistry lab course at the University of San Francisco. This experiment used the extraction and analysis of thyme leaves to familiarize students with an integrated laboratory approach, which is becoming increasingly popular in undergraduate chemistry education. The first goal of our research was to adapt the parameters of the experiment to the science writing heuristic (SWH), which moves away from verification-based activities and towards problem-based learning. A lab manual formatted for the SWH gives students …

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Synthesis Of Self-Immolative Rhodamine Based Theranostic Agent, Jonathan Alexander, Alessandra Rivera, Nathaniel Garrison May 2020

Synthesis Of Self-Immolative Rhodamine Based Theranostic Agent, Jonathan Alexander, Alessandra Rivera, Nathaniel Garrison

Creative Activity and Research Day - CARD

Theranostic agents, a class of molecules that simultaneously serve both a diagnostic and therapeutic function, enable in vivo imaging for early diagnosis and targeted drug delivery within a single entity. Due to recent advances in the synthesis and photophysical properties of the rhodamine scaffold, rhodamine dyes present a promising new direction for theranostic research. Toward the goal of exploring rhodamine dyes as self-immolative prodrugs for theranostic applications, we have synthesized a rhodamine precursor via a telescoped radical bromination/hydrolysis. Upon completion of the full rhodamine synthesis, we will explore and optimize the kinetics of its “turn-on” fluorescence and drug release in …

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Exploring The Effect Of Tris Buffer Concentration On Electrochemical Biosensors, Lucas Galante May 2020

Exploring The Effect Of Tris Buffer Concentration On Electrochemical Biosensors, Lucas Galante

Creative Activity and Research Day - CARD

Electrochemical biosensors show promise in the medical field for detection of genetic mutations and could translate well into point-of-care devices. Mutations of DNA can be sensitively and accurately detected through a series of electrochemical melts in which the less stable mutated DNA melts faster than the unmutated DNA. In previous work in our laboratory, we measured the extent of this melting by using square wave voltammetry and comparing peak heights. In this work we explored the effects of varied Tris buffer concentrations (5 mM, 10 mM, 20 mM, 30 mM, 40mM, 50 mM, and 100 mM) on cyclic and square …

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Towards The Development Of Redox-Responsive Eu(Iii) Complexes For Cancer Imaging, Matthew Derfus May 2020

Towards The Development Of Redox-Responsive Eu(Iii) Complexes For Cancer Imaging, Matthew Derfus

Creative Activity and Research Day - CARD

Cancer cells display redox dysregulation and lowered cytosolic pH as a means to maintain their over-proliferation. The development of an approach to probe tissue redox state could potentially allow discrimination between healthy and cancerous tissues. Magnetic Resonance Imaging (MRI) is a non-invasive technique used in the diagnosis of a variety of pathologies. The high spatial resolution and its use of non-ionizing radiation make MRI an attractive technique for cancer screening and detection. The quality of an MR image can be further enhanced with the aid of contrast agents, the majority of which are Gd(III) complexes. Gd(III) complexes provide positive contrast …

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Side-Chain Effects On The Mri And Optical Properties Of Bimodal Imaging Agents, Marisa Poveda May 2020

Side-Chain Effects On The Mri And Optical Properties Of Bimodal Imaging Agents, Marisa Poveda

Creative Activity and Research Day - CARD

In the management of cancer distinguishing tumor margins is an ongoing issue that can lead to insufficient removal of cancerous cells or excision of healthy tissue. To overcome this, bimodal imaging agents can be used for preoperative MR imaging to localize the bulk of a tumor, while intraoperative fluorescence imaging illuminates tumor margins for more accurate removal of diseased tissue. Lanthanide ions such as Tb(III) and Eu(III) display luminescent capabilities with long-lived luminescence lifetimes, and when chelated with a chromophore containing ligand, these compounds have the potential to act as both MR and optical imaging probes. The goal of this …

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A Ficellomycin Inspired Platform: Modulating Cytotoxicity By Tuning The Instability Of Substituted Azabicyclo[3.1.0]Hexanes, Nathaniel Garrison May 2020

A Ficellomycin Inspired Platform: Modulating Cytotoxicity By Tuning The Instability Of Substituted Azabicyclo[3.1.0]Hexanes, Nathaniel Garrison

Creative Activity and Research Day - CARD

DNA-damaging natural products, despite their promising activity, are often too toxic for clinical use as anti-cancer chemotherapies. Novel strategies to effectively modulate their cytotoxicity could expand the arsenal of usable drugs. Ficellomycin, a cytotoxic, DNA-alkylating antibiotic with a rare and unstable azabicyclo[3.1.0]hexane core, undergoes an intramolecular cyclization to render itself inert outside of a narrow pH range. Exploration of ficellomycin’s natural capacity for self-regulation may present a novel strategy for modulation of cytotoxicity more generally. Toward this end, we have synthesized a protected ficellomycin precursor in four steps and 6% overall yield. Key steps in the sequence include Sharpless asymmetric …

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Active/Transfer Learning With Medical Imaging, Nicholas Kebbas, Maggie Lu May 2020

Active/Transfer Learning With Medical Imaging, Nicholas Kebbas, Maggie Lu

Creative Activity and Research Day - CARD

We've developed a robust web application to assist researchers in improving the accuracy of their Machine Learning Models. The system provides an image labeling web interface so that researchers can label and classify the models, and multiple data visualizations that help researchers identify and resolve inconsistencies between the classifications determined by their models and user feedback.

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Investigating The Mechanism Of The E.Coli Atp-Binding Cassette Transporter Metni, Matthew Foronda May 2020

Investigating The Mechanism Of The E.Coli Atp-Binding Cassette Transporter Metni, Matthew Foronda

Creative Activity and Research Day - CARD

Intracellular chemical homeostasis is vital for cell survival. A key component for the maintenance of this homeostasis is ABC (ATP-binding cassette) transporters. These highly-conserved transporters utilize the energy from ATP binding and hydrolysis to move a wide array of substrates against their chemical gradient. Mutations can lead to a variety of diseases including cystic fibrosis and drug-resistant tumors. In order to solve these issues, these transporters must be well-studied. This project focuses on the mechanism of the methionine importer MetNI in E. coli, a reliable model for many transporters. Using fluorescence anisotropy, the apo-form of the substrate-binding protein (SBP) was …

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Oxidation Of Alpha-Pinene Initiated By O(3p) And Analyze Via Synchrotron Radiation, Ryan Rodriguez May 2020

Oxidation Of Alpha-Pinene Initiated By O(3p) And Analyze Via Synchrotron Radiation, Ryan Rodriguez

Creative Activity and Research Day - CARD

Alpha-pinene oxidation is initiated via photolytically generated atomic oxygen O(3P). Reactions were analyzed at 550 K under 4 torr and 750 K at 5 torr. Reaction products are analyzed using multiplexed photoionization mass spectrometry. Vacuum ultraviolet synchrotron radiation is generated at the Advanced Light Source at the Lawrence Berkeley National Laboratory. Kinetic time traces are used to identify primary products, which are then characterized by comparing the experimental photoionization spectra to literature and/or simulated spectra. Calculations using the CBS-QB3 composite method suggest oxygen addition is the favorable pathway vs hydrogen abstraction, agreeing with experimental data. Branching fractions have determined for …

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Probing The Oxidation Chemistry Of Dimethoxymethane, A Model Ome Fuel, Rory Mcclish May 2020

Probing The Oxidation Chemistry Of Dimethoxymethane, A Model Ome Fuel, Rory Mcclish

Creative Activity and Research Day - CARD

The threat posed by anthropogenic global warming, along with attached mitigation policies, drives the search for alternative fuels or additives; this search requires understanding the combustion chemistry of possible biofuel candidates. The low-temperature oxidation of a potential diesel fuel substitute, dimethoxymethane (DMM, m/z 76), is herein investigated at 500K, 600K, and 700K using synchrotron radiation coupled with multiplexed photoionization mass spectrometry at the Advanced Light Source within the Lawrence Berkeley National Laboratory. The experimental data is resolved in 3 dimensions: time, mass, and photon energy; this allows for identification, characterization, and quantification of primary products. Energetics calculations are carried out …

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Evaluation Of Visualization Techniques For Communicating Off-Screen Data, Tony Jimenez May 2020

Evaluation Of Visualization Techniques For Communicating Off-Screen Data, Tony Jimenez

Creative Activity and Research Day - CARD

Worldwide, the use of mobile devices like tablets has begun to integrate themselves in people’s daily lives. People have thus begun to bring over desktop applications, more specifically visualization applications, into the mobile atmosphere. However, this brings forth some challenges, like how to manage screen space and how the visualizations should present the relevant information. Our take on this was to use various aggregations that would allow users to see data elements that would otherwise be off-screen. We thought it was best to create a variety of different aggregations, allowing us to figure out the best method of the group. …

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Discovering New Strong Gravitational Lenses In The Desi Legacy Imaging Surveys, Xiaosheng Huang, Christopher Storfer, A. Gu, V. Ravi, A. Pilon, W. Sheu, R. Venguswamy, S. Bankda, A. Dey, M. Landriau, D. Lang, A. Meisner, J. Moustakas, A. D. Myers, R. Sajith, E. F. Schlafly, D. J. Schlegel May 2020

Discovering New Strong Gravitational Lenses In The Desi Legacy Imaging Surveys, Xiaosheng Huang, Christopher Storfer, A. Gu, V. Ravi, A. Pilon, W. Sheu, R. Venguswamy, S. Bankda, A. Dey, M. Landriau, D. Lang, A. Meisner, J. Moustakas, A. D. Myers, R. Sajith, E. F. Schlafly, D. J. Schlegel

Physics and Astronomy

We have conducted a search for new strong gravitational lensing systems in the Dark Energy Spectroscopic Instrument Legacy Imaging Surveys’ Data Release 8. We use deep residual neural networks, building on previous work presented in Huang et al. (2020). These surveys together cover approximately one third of the sky visible from the northern hemisphere, reaching a z-band AB magnitude of ∼ 22.5. We compile a training sample that consists of known lensing systems as well as non-lenses in the Legacy Surveys and the Dark Energy Survey. After applying our trained neural networks to the survey data, we visually inspect and …

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The Impact Of Extreme Heat On Environmental Justice Communities In California: Assessing Equity In Climate Action Plans, Karishma S. Becha May 2020

The Impact Of Extreme Heat On Environmental Justice Communities In California: Assessing Equity In Climate Action Plans, Karishma S. Becha

Master's Projects and Capstones

Climate change projections suggest extreme heat events will be more frequent over the next few decades. Extreme heat has both negative environmental and social impacts as it affects energy security, public health by increasing the risk of heat-related illnesses and stresses food and crop supply through prolonged droughts. The impacts of extreme heat will also disproportionately affect communities of low economic status. Because of this, there is a need for better climate action plans that can adapt to and mitigate the impacts brought upon by extreme heat that does not disproportionately impact vulnerable communities. This research analyzed local government Climate …

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Identifying Group Contributions In Nba Lineups With Spectral Analysis, Stephen Devlin, David Uminsky Jan 2020

Identifying Group Contributions In Nba Lineups With Spectral Analysis, Stephen Devlin, David Uminsky

Mathematics

We address the question of how to quantify the contributions of groups of players to team success. Our approach is based on spectral analysis, a technique from algebraic signal processing, which has several appealing features. First, our analysis decomposes the team success signal into components that are naturally understood as the contributions of player groups of a given size: individuals, pairs, triples, fours, and full five-player lineups. Secondly, the decomposition is orthogonal so that contributions of a player group can be thought of as pure: Contributions attributed to a group of three, for example, have been separated from the lower-order …

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