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Articles 1 - 14 of 14
Full-Text Articles in Physical Sciences and Mathematics
Microwave Regeneration And Thermal And Oxidative Stability Of Imidazolium Cyanopyrrolide Ionic Liquid For Direct Air Capture Of Carbon Dioxide, Yun-Yang Lee, Eda Cagli, Aidan Klemm, Ruth Dikki
Microwave Regeneration And Thermal And Oxidative Stability Of Imidazolium Cyanopyrrolide Ionic Liquid For Direct Air Capture Of Carbon Dioxide, Yun-Yang Lee, Eda Cagli, Aidan Klemm, Ruth Dikki
Faculty Scholarship
Understanding the oxidative and thermal degradation of CO2 sorbents is essential for assessing long-term sorbent stability in direct air capture (DAC). The potential degradation pathway of imidazolium cyanopyrrolide, an ionic liquid (IL) functionalized for superior CO2 capacity and selectivity, is evaluated under accelerated degradation conditions to elucidate the secondary reactions that can occur during repetitive absorption-desorption thermal-swing cycles. The combined analysis from various spectroscopic, chromatographic, and thermal gravimetric measurements indicated that radical and SN2 mechanisms in degradation are encouraged by the nucleophilicity of the anion. Thickening of the liquid and gas evolution are accompanied by 50 % reduction in CO2 …
Minimal Auxiliary Basis Set Approach For The Electronic Excitation Spectra Of Organic Molecules, Zehao Zhou, Shane M. Parker
Minimal Auxiliary Basis Set Approach For The Electronic Excitation Spectra Of Organic Molecules, Zehao Zhou, Shane M. Parker
Faculty Scholarship
We report a minimal auxiliary basis model for time-dependent density functional theory (TDDFT) with hybrid density functionals that can accurately reproduce excitation energies and absorption spectra from TDDFT while reducing cost by about \change{two} orders of magnitude. Our method, dubbed TDDFT-ris, employs the resolution-of-the-identity technique with just one $s$-type auxiliary basis function per atom for the linear response operator, where the Gaussian exponents are parametrized across the periodic table using %using tabulated atomic radii with a single global scaling factor. By tuning on a small test set, we determine a single functional-independent scale factor that balances errors in excitation energies …
Triarylmethyl Cation-Catalyzed Three-Component Coupling For The Synthesis Of Unsymmetrical Bisindolylmethanes [Post-Print], William Patterson, Kelly Lucas, Vanessa Jones, Zhenghua Chen, Kevin Bardelski, Melissa Guarino-Hotz, Cheyenne S. Brindle
Triarylmethyl Cation-Catalyzed Three-Component Coupling For The Synthesis Of Unsymmetrical Bisindolylmethanes [Post-Print], William Patterson, Kelly Lucas, Vanessa Jones, Zhenghua Chen, Kevin Bardelski, Melissa Guarino-Hotz, Cheyenne S. Brindle
Faculty Scholarship
An efficient synthesis of unsymmetrical bisindolylmethanes has been accomplished using triarylmethyl cations to catalyze the reaction of N-arylimines with two different indoles. Optimization of the organocatalyst by tuning cation stability allows for excellent single addition selectivity when coupled with p-nitrophenyl imines. The optimal catalyst is commercially available, and the reaction minimizes waste and environmental impact by employing a one-to-one ratio of starting materials. The intermediates can be isolated or used in situ in a one-pot two-step reaction to generate unsymmetrical bisindolylmethanes in high yields. The reaction tolerates a broad range of imines with the highest yields observed for …
Supported Bilayer Membranes For Reducing Cell Adhesion In Microfluidic Devices [Post-Print], Julia R. Clapis, Mengqi Jonathan Fan, Michelle Kovarik
Supported Bilayer Membranes For Reducing Cell Adhesion In Microfluidic Devices [Post-Print], Julia R. Clapis, Mengqi Jonathan Fan, Michelle Kovarik
Faculty Scholarship
The high surface area-to-volume ratio of microfluidic channels makes them susceptible to fouling and clogging when used for biological analyses, including cell-based assays. We evaluated the role of electrostatic and van der Waals interactions in cell adhesion in PDMS microchannels coated with supported lipid bilayers and identified conditions that resulted in minimal cell adhesion. For low ionic strength buffer, optimum results were obtained for a zwitterionic coating of pure egg phosphatidylcholine; for a rich growth medium, the best results were obtained for zwitterionic bilayers or those with slight negative or moderate positive charge from the incorporation of 5-10 mol% egg …
Review Of Student-Built Spectroscopy Instrumentation Projects, Michelle L. Kovarik, Julia R. Clapis, K. Ana Romano-Pringle
Review Of Student-Built Spectroscopy Instrumentation Projects, Michelle L. Kovarik, Julia R. Clapis, K. Ana Romano-Pringle
Faculty Scholarship
Copyright © 2020 American Chemical Society and Division of Chemical Education, Inc. One challenge of teaching chemical analysis is the proliferation of sophisticated, but often impenetrable, instrumentation in the modern laboratory. Complex instruments, and the software that runs them, distance students from the physical and chemical processes that generate the analytical signal. A solution to this challenge is the introduction of a student-driven instrument-building project. Visible absorbance spectroscopy is well-suited to such a project due to its relative simplicity and the ubiquity of absorbance measurements. This Article reviews simple instructor- A nd student-built instruments for spectroscopy, providing an overview of …
Collaborative Learning Exercises For Teaching Protein Mass Spectrometry [Post-Print], Michelle Kovarik, Jill K. Robinson
Collaborative Learning Exercises For Teaching Protein Mass Spectrometry [Post-Print], Michelle Kovarik, Jill K. Robinson
Faculty Scholarship
A collaborative learning module for teaching protein mass spectrometry has been developed to overcome common obstacles to incorporating the modern topic of biological mass spectrometry into the undergraduate chemistry curriculum. Protein mass spectrometry data is provided to eliminate the need for expensive instrumentation, and an instructor’s manual gives necessary details for those unfamiliar with the topic. The first section provides background information on proteins and the field of proteomics. The second section describes the use of electrospray ionization to determine the molecular weight of a protein. The third section shows how to identify a protein using peptide mass mapping, and …
Effect Of Loading Method On A Peptide Substrate Reporter In Intact Cells [Post-Print], Rahuljeet Chadha, Grigorii Kalminskii, Allison Tierney, Joshua Knopf, Lorena Lazo De La Vega, Berjana Mcelrath, Michelle Kovarik
Effect Of Loading Method On A Peptide Substrate Reporter In Intact Cells [Post-Print], Rahuljeet Chadha, Grigorii Kalminskii, Allison Tierney, Joshua Knopf, Lorena Lazo De La Vega, Berjana Mcelrath, Michelle Kovarik
Faculty Scholarship
Studies of live cells often require loading of exogenous molecules through the cell membrane; however, effects of loading method on experimental results are poorly understood. Therefore, in this work, we compared three methods for loading a fluorescently labeled peptide into cells of the model organism Dictyostelium discoideum. We optimized loading by pinocytosis, electroporation, and myristoylation to maximize cell viability and characterized loading efficiency, localization, and uniformity. We also determined how the loading method affected measurements of enzyme activity on the peptide substrate reporter using capillary electrophoresis. Loading method had a strong effect on the stability and phosphorylation of the …
Pseudoelasticity At Large Strains In Au Nanocrystals [Post-Print], X. Wendy Gu, Lindsey A. Hanson, Carissa N. Eisler, Matthew A. Koc, A. Paul Alivisatos
Pseudoelasticity At Large Strains In Au Nanocrystals [Post-Print], X. Wendy Gu, Lindsey A. Hanson, Carissa N. Eisler, Matthew A. Koc, A. Paul Alivisatos
Faculty Scholarship
© 2018 American Physical Society. Pseudoelasticity in metals is typically associated with phase transformations (e.g., shape memory alloys) but has recently been observed in sub-10 nm Ag nanocrystals that rapidly recovered their original shape after deformation to large strains. The discovery of pseudoelasticity in nanoscale metals dramatically changes the current understanding of the properties of solids at the smallest length scales, and the motion of atoms at surfaces. Yet, it remains unclear whether pseudoelasticity exists in different metals and nanocrystal sizes. The challenge of observing deformation at atomistic to nanometer length scales has prevented a clear mechanistic understanding of nanoscale …
Successfully Navigating The Early Years Of A Faculty Position, Michelle L. Kovarik, Christopher R. Harrison, Thomas J. Wenzel
Successfully Navigating The Early Years Of A Faculty Position, Michelle L. Kovarik, Christopher R. Harrison, Thomas J. Wenzel
Faculty Scholarship
No abstract provided.
Triarylmethyl Cation Catalysis: A Tunable Lewis Acid Organocatalyst For The Synthesis Of Bisindolylmethanes, Nicholas G. Boekell, Dana J. Cerone, Maria M. Boucher, Wilfried B. Nganyak Tentchou, Christine G. Reavis, Ifeanyi I. Okoh, Jordan O.A. Reid, Hayley E. Berg, Briana A. Chang, Cheyenne S. Brindle
Triarylmethyl Cation Catalysis: A Tunable Lewis Acid Organocatalyst For The Synthesis Of Bisindolylmethanes, Nicholas G. Boekell, Dana J. Cerone, Maria M. Boucher, Wilfried B. Nganyak Tentchou, Christine G. Reavis, Ifeanyi I. Okoh, Jordan O.A. Reid, Hayley E. Berg, Briana A. Chang, Cheyenne S. Brindle
Faculty Scholarship
Triarylmethyl cations serve as tunable organocatalysts for the synthesis of bisindolylmethanes. The catalyst structure can be modified to increase or decrease reactivity as needed to match the requirements of the substrate. High yields are achieved for a variety of substrates by using these green catalysts. Catalyst tuning allows for the use of less reactive electrophiles by increasing the reactivity of the catalyst. Acid-sensitive products can be isolated under these mild reaction conditions.
Interspecies Comparison Of Peptide Substrate Reporter Metabolism Using Compartment-Based Modeling [Post-Print], Allison Tierney, Nhat Pham, Kunwei Yang, Brooks Emerick, Michelle Kovarik
Interspecies Comparison Of Peptide Substrate Reporter Metabolism Using Compartment-Based Modeling [Post-Print], Allison Tierney, Nhat Pham, Kunwei Yang, Brooks Emerick, Michelle Kovarik
Faculty Scholarship
Peptide substrate reporters are fluorescently labeled peptides that can be acted upon by one or more enzymes of interest. Peptide substrates are readily synthesized and more easily separated than full-length protein substrates; however, they are often more rapidly degraded by peptidases. As a result, peptide reporters must be made resistant to proteolysis in order to study enzymes in intact cells and lysates. This is typically achieved by optimizing the reporter sequence in a single cell type or model organism, but studies of reporter stability in a variety of organisms are needed to establish the robustness and broader utility of these …
Analytical Chemistry Research At Primarily Undergraduate Institutions: Training Tomorrow’S Investigators [Post-Print], Michelle Kovarik
Analytical Chemistry Research At Primarily Undergraduate Institutions: Training Tomorrow’S Investigators [Post-Print], Michelle Kovarik
Faculty Scholarship
Primarily undergraduate institutions (PUIs) are a unique training ground for young scientists who work closely with faculty on their research. Researchers at PUIs face a number of challenges, including balancing research and teaching responsibilities, obtaining sufficient funding for projects, and training students in their first research experiences. Faculty at PUIs deploy a variety of strategies to address these challenges, and the resulting research provides important benefits to faculty, students, the analytical chemistry community, and society. This perspective discusses these challenges and benefits in detail. Additionally, several vignettes describe how specific faculty members have established and maintained productive research programs at …
Identification Of Disufide Bond Formation Between Mitoneet And Glutamate Dehydrogenase 1., Morgan Roberts, Jacquelyn Crail, Megan Laffoon, William Fernandez, Michael Menze, Mary Konkle
Identification Of Disufide Bond Formation Between Mitoneet And Glutamate Dehydrogenase 1., Morgan Roberts, Jacquelyn Crail, Megan Laffoon, William Fernandez, Michael Menze, Mary Konkle
Faculty Scholarship
MitoNEET is a protein that was identified as a drug target for diabetes, but its cellular function as well as its role in diabetes remains elusive. Protein pull-down experiments identified glutamate dehydrogenase 1 (GDH1) as a potential binding partner. GDH1 is a key metabolic enzyme with emerging roles in insulin regulation. MitoNEET forms a covalent complex with GDH1 through disulfide bond formation and acts as an activator. Proteomic analysis identified the specific cysteine residues that participate in the disulfide bond. This is the first report that effectively links mitoNEET to activation of the insulin regulator GDH1.
Conformational Behavior Of Symmetrical And Unsymmetrical Mono(Alkynylpeptide)-Tungsten Complexes [Post-Print], Timothy P. Curran, Whitney E. Smith, Peter C. Hendrickson
Conformational Behavior Of Symmetrical And Unsymmetrical Mono(Alkynylpeptide)-Tungsten Complexes [Post-Print], Timothy P. Curran, Whitney E. Smith, Peter C. Hendrickson
Faculty Scholarship
A series of N-protected amino acid alkynylesters were prepared by reaction of the amino acid carboxylate group with either propargyl alcohol (to yield the asymmetric esters 2a–c) or with 1, 4-but-2-yne diol (to yield the symmetric esters 3a–d). The alkynylesters were reacted with W(CO)3(dmtc)2 to yield monoalkyne complexes having the general formula W(CO)(dmtc)2(alkynyl ester). The monoalkyne complexes 6a–f were unstable in the presence of oxygen and had to be kept under an inert atmosphere. Analysis of the NMR spectra of the monoalkyne complexes showed that two diastereomers …