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Faculty Publications

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Articles 61 - 90 of 199

Full-Text Articles in Biochemistry

Traffic Lights For Catalysis: Stimuli-Responsive Molecular And Extended Catalytic Systems, Grace C. Thaggard, Johanna Haimeri, Roland A. Fischer Prof. Dr., Kyoung Chul Park, Natalia B. Shustova Prof. Dr. Mar 2023

Traffic Lights For Catalysis: Stimuli-Responsive Molecular And Extended Catalytic Systems, Grace C. Thaggard, Johanna Haimeri, Roland A. Fischer Prof. Dr., Kyoung Chul Park, Natalia B. Shustova Prof. Dr.

Faculty Publications

The advances made in the field of stimuli-responsive catalysis during the last five years with a focus on the novel recently-emerged directions and applications have been surveyed. Metal-free catalysts and organometallic complexes, as well as biomimetic systems and extended structures, which display switchable catalytic activity for a variety of organic transformations, are discussed. Light-activated systems comprised of photochromic molecules capable of modulating reaction rate, yield, or enantioselectivity based on geometric and electronic changes associated with photoisomerization are the focus of the detailed discussion. Alternative stimuli, including pH and temperature, which could be applied either alone or in combination with light, …

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Enhanced Structural Control Of Soft-Templated Mesoporous Inorganic Thin Films By Inert Processing Conditions, Maximilliano Jesus Jara Fornerod, Alberto Alvarez-Fernandez, Eric R. Williams, Miximillian W.A. Skoda, Beatriz Prieto-Simon, Nicolas H. Voelcker, Morgan Stefik, Marc-Oliver Coppens, Stefan Guldin Dec 2022

Enhanced Structural Control Of Soft-Templated Mesoporous Inorganic Thin Films By Inert Processing Conditions, Maximilliano Jesus Jara Fornerod, Alberto Alvarez-Fernandez, Eric R. Williams, Miximillian W.A. Skoda, Beatriz Prieto-Simon, Nicolas H. Voelcker, Morgan Stefik, Marc-Oliver Coppens, Stefan Guldin

Faculty Publications

Mesoporous thin films are widely used for applications in need of high surface area and efficient mass and charge transport properties. A well-established fabrication process involves the supramolecular assembly of organic molecules (e.g., block copolymers and surfactants) with inorganic materials obtained by sol-gel chemistry. Typically, subsequent calcination in air removes the organic template and reveals the porous inorganic network. A significant challenge for such coatings is the anisotropic shrinkage due to the volume contraction related to solvent evaporation, inorganic condensation, and template removal, affecting the final porosity as well as pore shape, size, arrangement, and accessibility. Here, we show that …

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Direct Measurement Of Stokes–Einstein Diffusion Of Cowpea Mosaic Virus With 19 Μs-Resolved Xpcs, Kacper Switalski, Jingyu Fang, Luxi Li, Miaoqi Chu, Erik Sarnello, Pete Jemian, Tao Li, Qian Wang, Qingteng Zhang Oct 2022

Direct Measurement Of Stokes–Einstein Diffusion Of Cowpea Mosaic Virus With 19 Μs-Resolved Xpcs, Kacper Switalski, Jingyu Fang, Luxi Li, Miaoqi Chu, Erik Sarnello, Pete Jemian, Tao Li, Qian Wang, Qingteng Zhang

Faculty Publications

Brownian motion of Cowpea mosaic virus (CPMV) in water was measured using small-angle X-ray photon correlation spectroscopy (SA-XPCS) at 19.2 mu s time resolution. It was found that the decorrelation time tau(Q) = 1/DQ(2) up to Q = 0.091 nm(-1). The hydrodynamic radius R-H determined from XPCS using Stokes-Einstein diffusion D = kT/(6 pi eta R-H) is 43% larger than the geometric radius R-0 determined from SAXS in the 0.007 M K3PO4 buffer solution, whereas it is 80% larger for CPMV in 0.5 M NaCl and 104% larger in 0.5 M (NH4)(2)SO4, a possible effect of aggregation as well as …

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Compositionally And Density Stratified Igneous Terrain In Jezero Crater, Mars, Roger C. Wiens, Arya Udry, Olivier Beyssac, Cathy Quantin-Nataf, Nicolas Mangold, Agnès Cousin, Lucia Mandon, Tanja Bosak, Olivier Forni, Scott M. Mclennan, Violaine Sautter, Adrian Cousin, Karim Benzerara, Jeffrey R. Johnson, Lisa Mayhew, Sylvestre Maurice, Ryan B. Maurice, Ryan B. Anderson, Samuel M. Clegg, Larry Crumpler, Stanley M. Angel Aug 2022

Compositionally And Density Stratified Igneous Terrain In Jezero Crater, Mars, Roger C. Wiens, Arya Udry, Olivier Beyssac, Cathy Quantin-Nataf, Nicolas Mangold, Agnès Cousin, Lucia Mandon, Tanja Bosak, Olivier Forni, Scott M. Mclennan, Violaine Sautter, Adrian Cousin, Karim Benzerara, Jeffrey R. Johnson, Lisa Mayhew, Sylvestre Maurice, Ryan B. Maurice, Ryan B. Anderson, Samuel M. Clegg, Larry Crumpler, Stanley M. Angel

Faculty Publications

Before Perseverance, Jezero crater's floor was variably hypothesized to have a lacustrine, lava, volcanic airfall, or aeolian origin. SuperCam observations in the first 286 Mars days on Mars revealed a volcanic and intrusive terrain with compositional and density stratification.The dominant lithology along the traverse is basaltic, with plagioclase enrichment in stratigraphically higher locations. Stratigraphically lower, layered rocks are richer in normative pyroxene. The lowest observed unit has the highest inferred density and is olivine-rich with coarse (1.5 millimeters) euhedral, relatively unweathered grains, suggesting a cumulate origin. This is the first martian cumulate and shows similarities to martian meteorites, which also …

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Invited Perspective: Existing Rules For Disinfection By-Products Are Good, But They Are Not Enough, Susan D. Richardson Aug 2022

Invited Perspective: Existing Rules For Disinfection By-Products Are Good, But They Are Not Enough, Susan D. Richardson

Faculty Publications

No abstract provided.

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Author Correction: In Situ Recording Of Mars Soundscape (Nature, (2022), 605, 7911, (653-658), 10.1038/S41586-022-04679-0), S. Maurice, B. Chide, N. Murdoch, R. D. Lorenz, D. Mimoun, R. C. Wiens, A. Stott, X. Jacob, T. Bertrand, F. Montmessin, N. L. Lanza, C. Alvarez-Llamas, S. M. Angel Ph.D., M. Aung, J. Balaram, O. Beyssac, A. Cousin, G. Delory, O. Forni, T. Fouchet, O. Gasnault, H. Grip, M. Hecht, J. Hoffman, J. Laserna, J. Lasue, J. Maki, J. Mcclean, P. Y. Meslin, S. Le Mouélic, S. Le Mouélic, A. Munguira Jul 2022

Author Correction: In Situ Recording Of Mars Soundscape (Nature, (2022), 605, 7911, (653-658), 10.1038/S41586-022-04679-0), S. Maurice, B. Chide, N. Murdoch, R. D. Lorenz, D. Mimoun, R. C. Wiens, A. Stott, X. Jacob, T. Bertrand, F. Montmessin, N. L. Lanza, C. Alvarez-Llamas, S. M. Angel Ph.D., M. Aung, J. Balaram, O. Beyssac, A. Cousin, G. Delory, O. Forni, T. Fouchet, O. Gasnault, H. Grip, M. Hecht, J. Hoffman, J. Laserna, J. Lasue, J. Maki, J. Mcclean, P. Y. Meslin, S. Le Mouélic, S. Le Mouélic, A. Munguira

Faculty Publications

In the version of this article initially published, the Acknowledgements statement was missing the text “Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004),” which has now been inserted in the HTML and PDF versions of the article.

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Structure-Property Investigations In Urea Tethered Iodinated Triphenylamines, Muhammad Saddam Hossain, Fiaz Ahmed, Stavros G. Karakalos, Mark D. Smith, Namrata Pant, Sophya V. Garashchuk, Andrew B, Greytak, Pablo Docampo, Linda S. Shimizu Jul 2022

Structure-Property Investigations In Urea Tethered Iodinated Triphenylamines, Muhammad Saddam Hossain, Fiaz Ahmed, Stavros G. Karakalos, Mark D. Smith, Namrata Pant, Sophya V. Garashchuk, Andrew B, Greytak, Pablo Docampo, Linda S. Shimizu

Faculty Publications

Herein, we report structural, computational, and conductivity studies on urea-directed self-assembled iodinated triphenylamine (TPA) derivatives. Despite numerous reports of conductive TPAs, the challenges of correlating their solid-state assembly with charge transport properties hinder the efficient design of new materials. In this work, we compare the assembled structures of a methylene urea bridged dimer of di-iodo TPA (1) and the corresponding methylene urea di-iodo TPA monomer (2) with a di-iodo mono aldehyde (3) control. These modifications lead to needle shaped crystals for 1 and 2 that are organized by urea hydrogen bonding, π⋯π stacking, I⋯I, and I⋯π interactions as determined by …

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Luminescence And Scintillation In The Niobium Doped Oxyfluoride Rb4Ge5O9F6:Nb, Darren Carone, Vladislav V. Klepov, Scott T. Misture, Joseph C. Schaeperkoetter, Luiz G. Jacobsohn, Mina Aziziha, Juliano Schorne-Pinto, Stuart A. J. Thomson, Adrian T. Hines, Theodore M. Besmann, Hans Conrad Zur Loye Jun 2022

Luminescence And Scintillation In The Niobium Doped Oxyfluoride Rb4Ge5O9F6:Nb, Darren Carone, Vladislav V. Klepov, Scott T. Misture, Joseph C. Schaeperkoetter, Luiz G. Jacobsohn, Mina Aziziha, Juliano Schorne-Pinto, Stuart A. J. Thomson, Adrian T. Hines, Theodore M. Besmann, Hans Conrad Zur Loye

Faculty Publications

A new niobium-doped inorganic scintillating oxyfluoride, Rb4Ge5O9F6:Nb, was synthesized in single crystal form by high-temperature flux growth. The host structure, Rb4Ge5O9F6, crystallizes in the orthorhombic space group Pbcn with lattice parameters a = 6.98430(10) Å, b = 11.7265(2) Å, and c = 19.2732(3) Å, consisting of germanium oxyfluoride layers made up of Ge3O9 units connected by GeO3F3 octahedra. In its pure form, Rb4Ge5O9F6 shows neither luminescence nor scintillation but when doped …

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Highly Swellable Hydrogels Prepared From Extensively Oxidized Lignin, Jihyeon Hwang, Daniella V. Martinez, Estevan J. Martinez, Gift Metavarayuth, Dustin Goodlett, Qi Wang, Mitra Ganewatta, Michael S. Kent, Chuanbing Tang Jun 2022

Highly Swellable Hydrogels Prepared From Extensively Oxidized Lignin, Jihyeon Hwang, Daniella V. Martinez, Estevan J. Martinez, Gift Metavarayuth, Dustin Goodlett, Qi Wang, Mitra Ganewatta, Michael S. Kent, Chuanbing Tang

Faculty Publications

Biopolymers such as lignin are gaining renewed appeal due to the need for sustainable materials. Herein, we used chelator-mediated Fenton (CMF) chemistry to oxidize Kraft lignin to develop sustainable super absorbent materials. The CMF chemistry adds oxygen, opens aromatic rings and increases COOH content, producing hydrophilic lignin without depolymerization. UV absorption, molecular weight, elemental analysis, and titration were used to study the chemical compositions of CMF-processed lignin. Then the chemically modified hydrophilic lignin was used to produce lignin-based hydrogels utilizing an aqueous polymerization and cross-linking reaction that enabled tunable properties. The resulting lignin hydrogels absorbed water up to 96% and …

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Understanding Rapid Intercalation Materials One Parameter At A Time, Wessel Van Den Bergh, Morgan Stefik Jun 2022

Understanding Rapid Intercalation Materials One Parameter At A Time, Wessel Van Den Bergh, Morgan Stefik

Faculty Publications

Demand for fast, energy-dense storage drives the research into nanoscale intercalation materials. Nanomaterials accelerate kinetics and can modify reaction path thermodynamics, intercalant solubility, and reversibility. The discovery of intercalation pseudocapacitance has opened questions about their fundamental operating principles. For example, are their capacitor-like current responses caused by storing energy in special near-surface regions or rather is this response due to normal intercalation limited by a slower faradaic surface-reaction? This review highlights emerging methods combining tailored nanomaterials with the process of elimination to disambiguate cause-and-effect at the nanoscale. This method is applied to multiple intercalation pseudocapacitive materials showing that the timescales …

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Unusual High-Frequency Mechanical Properties Of Polymer-Grafted Nanoparticle Melts, Mayank Jhalaria, Yu Chang, Yucheng Huang, Brian C. Benicewicz, Sanat K. Kumar, George Fytas May 2022

Unusual High-Frequency Mechanical Properties Of Polymer-Grafted Nanoparticle Melts, Mayank Jhalaria, Yu Chang, Yucheng Huang, Brian C. Benicewicz, Sanat K. Kumar, George Fytas

Faculty Publications

Brillouin light spectroscopy is used to measure the elastic moduli of spherical polymer-grafted nanoparticle (GNP) melts as a function of chain length at fixed grafting density (0.47  chains/nm2) and nanoparticle radius (8 nm). While the moduli follow a rule of mixtures (Wood’s law) for long chains, they display enhanced elasticity and anomalous dissipation for graft chains <1⁢0⁢0  kDa. GNP melts with long polymers at high 𝜎 have a dry zone near the GNP core, surrounded by a region where the grafts can interpenetrate with chain fragments from adjacent GNPs. We propose that the departures from Wood’s law for short chains are due to the effectively larger silica volume fraction in the region where sound propagates—this is caused by the short, interpenetrated chain fragments being pushed out of the way. We thus conclude that transport mechanisms (of gas, ions, sound, thermal phonons) in GNP melts are radically different if interpenetrated chain segments can be “pushed out of the way” or not. This provides a facile new means for manipulating the properties of these materials.

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In Situ Recording Of Mars Soundscape, S. Maurice, B. Chide, N. Murdoch, R. D. Lorenz, D. Mimoun, R. C. Wiens, A. Stott, X. Jacob, T. Bertrand, F. Montmessin, N. L. Lanza, C. Alvarez-Llamas, Stanley M. Angel, M. Aung, J. Balaram, O. Beyssac, A. Cousin, G. Delory, O. Forni, T. Fouchet, Et. Al. Apr 2022

In Situ Recording Of Mars Soundscape, S. Maurice, B. Chide, N. Murdoch, R. D. Lorenz, D. Mimoun, R. C. Wiens, A. Stott, X. Jacob, T. Bertrand, F. Montmessin, N. L. Lanza, C. Alvarez-Llamas, Stanley M. Angel, M. Aung, J. Balaram, O. Beyssac, A. Cousin, G. Delory, O. Forni, T. Fouchet, Et. Al.

Faculty Publications

Before the Perseverance rover landing, the acoustic environment of Mars was unknown. Models predicted that: (1) atmospheric turbulence changes at centimetre scales or smaller at the point where molecular viscosity converts kinetic energy into heat1, (2) the speed of sound varies at the surface with frequency2,3 and (3) high-frequency waves are strongly attenuated with distance in CO2 (refs. 2,3,4). However, theoretical models were uncertain because of a lack of experimental data at low pressure and the difficulty to characterize turbulence or attenuation in a closed environment. Here, using Perseverance …

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One Planet: One Health. A Call To Support The Initiative On A Global Science-Policy Body On Chemicals And Waste, Werner Brack, Damia Barcelo Culleres, Alistair B.A. Boxall, Helene Budzinski, Sara Castiglioni, Adrian Covaci, Valeria Dulio, Beate I. Escher, Peter Fantke, Faith Kandie, Despo Fatta-Kassinos, Felix J. Hernandez, Klara Hilscherova, Juliane Hollender, Henner Hollert, Annika Jahnke, Barbara Kasprzyk-Hordern, Stuart J. Khan, Andreas Kortenkamp, Klaus Kuemmerer, Brice Lalonde, Marja H. Lamoree, Yves Levi, Pablo Antonio Lara Martin, Cassiana C. Montagner, Christian Mougin, Titus Msagati, Joerg Oehlmann, Leo Posthuma, Malcolm Reid, Martin Reinhard, Susan D. Richardson, Et. Al. Mar 2022

One Planet: One Health. A Call To Support The Initiative On A Global Science-Policy Body On Chemicals And Waste, Werner Brack, Damia Barcelo Culleres, Alistair B.A. Boxall, Helene Budzinski, Sara Castiglioni, Adrian Covaci, Valeria Dulio, Beate I. Escher, Peter Fantke, Faith Kandie, Despo Fatta-Kassinos, Felix J. Hernandez, Klara Hilscherova, Juliane Hollender, Henner Hollert, Annika Jahnke, Barbara Kasprzyk-Hordern, Stuart J. Khan, Andreas Kortenkamp, Klaus Kuemmerer, Brice Lalonde, Marja H. Lamoree, Yves Levi, Pablo Antonio Lara Martin, Cassiana C. Montagner, Christian Mougin, Titus Msagati, Joerg Oehlmann, Leo Posthuma, Malcolm Reid, Martin Reinhard, Susan D. Richardson, Et. Al.

Faculty Publications

The chemical pollution crisis severely threatens human and environmental health globally. To tackle this challenge the establishment of an overarching international science–policy body has recently been suggested. We strongly support this initiative based on the awareness that humanity has already likely left the safe operating space within planetary boundaries for novel entities including chemical pollution. Immediate action is essential and needs to be informed by sound scientific knowledge and data compiled and critically evaluated by an overarching science–policy interface body. Major challenges for such a body are (i) to foster global knowledge production on exposure, impacts and governance going beyond …

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Amorphization Of Pseudocapacitive T−Nb2O5 Accelerates Lithium Diffusivity As Revealed Using Tunable Isomorphic Architectures, Wessel Van Den Bergh, Sean Wechsler, Hasala Nadeesini Lokupitiya, Lauren Jarocha, Kwangnam Kim, James Chapman, Kyoung E. Kweon, Brandon C. Wood, Steve Heald, Morgan Stefik Phd Feb 2022

Amorphization Of Pseudocapacitive T−Nb2O5 Accelerates Lithium Diffusivity As Revealed Using Tunable Isomorphic Architectures, Wessel Van Den Bergh, Sean Wechsler, Hasala Nadeesini Lokupitiya, Lauren Jarocha, Kwangnam Kim, James Chapman, Kyoung E. Kweon, Brandon C. Wood, Steve Heald, Morgan Stefik Phd

Faculty Publications

Intercalationpseudocapacitancecan combinecapacitor-likepower densitieswith battery-likeenergy densities.Such surface-limitedbehaviorrequiresrapid diffusionwhere amorphizationcan increasesolid-statediffusivity.Here intercalationpseudoca-pacitivematerialswith tailoredextentsof amorphizationin T-Nb2O5are first reported.Amorphizationwas characterizedwithWAXS, XPS, XAFS, and EPR which suggesteda peroxide-rich(O22) surface that was consistentwith DFT predictions.A seriesof tunableisomorphicarchitecturesenabledcomparisonswhileindependentlyvaryingtransportparameters.Throughprocessof elimination,solid-statelithium diffusionwas identifiedas thedominantdiffusive-constraintdictatingthe maximumvoltagesweep rate for surface-limitedkinetics(vSLT), termed the Surface-LimitedThreshold(SLT). ThevSLTincreasedwith amorphizationhoweverstable cycling requiredcrystallineT-Nb2O5. A current-responsemodel using series-impedanceswell-matchedtheseobservations.This perspectiverevealedthat amorphizationof T-Nb2O5enhancedsolid-statediffusionby 12.2% and increasedsurface-limitationsby 17.0% (stablesamples).This approachenabledretaining95% lithiationcapacityat ~800mVs1(1,600C-rate equivalent).

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Docking And Molecular Dynamic Of Microalgae Compounds As Potential Inhibitors Of Beta-Lactamase, Roberto Pestana-Nobles, Yani Aranguren-Diaz, Elwi Machado-Sierra, Juvenal Yosa, Nataly J. Galan-Freyle,, Laura X. Sepulveda-Montano, Daniel G. Kuroda, Leonardo C. Pacheco-Londono Feb 2022

Docking And Molecular Dynamic Of Microalgae Compounds As Potential Inhibitors Of Beta-Lactamase, Roberto Pestana-Nobles, Yani Aranguren-Diaz, Elwi Machado-Sierra, Juvenal Yosa, Nataly J. Galan-Freyle,, Laura X. Sepulveda-Montano, Daniel G. Kuroda, Leonardo C. Pacheco-Londono

Faculty Publications

Bacterial resistance is responsible for a wide variety of health problems, both in children and adults. The persistence of symptoms and infections are mainly treated with beta-lactam antibiotics. The increasing resistance to those antibiotics by bacterial pathogens generated the emergence of extended-spectrum beta-lactamases (ESBLs), an actual public health problem. This is due to rapid mutations of bacteria when exposed to antibiotics. In this case, beta-lactamases are enzymes used by bacteria to hydrolyze the beta-lactam rings present in the antibiotics. Therefore, it was necessary to explore novel molecules as potential beta-lactamases inhibitors to find antibacterial compounds against infection caused by ESBLs. …

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Whole-Genome Sequencing And Rna-Seq Reveal Differences In Genetic Mechanism For Flowering Response Between Weedy Rice And Cultivated Rice, Richard S. Garcia, Sapphire Coronejo, Jonathan Concepcion, Prasanta K. Subudhi Feb 2022

Whole-Genome Sequencing And Rna-Seq Reveal Differences In Genetic Mechanism For Flowering Response Between Weedy Rice And Cultivated Rice, Richard S. Garcia, Sapphire Coronejo, Jonathan Concepcion, Prasanta K. Subudhi

Faculty Publications

Flowering is a key agronomic trait that influences adaptation and productivity. Previous studies have indicated the genetic complexity associated with the flowering response in a photoinsensitive weedy rice accession PSRR-1 despite the presence of a photosensitive allele of a key flowering gene Hd1. In this study, we used whole-genome and RNA sequencing data from both cultivated and weedy rice to add further insights. The de novo assembly of unaligned sequences predicted 225 genes, in which 45 were specific to PSRR-1, including two genes associated with flowering. Comparison of the variants in PSRR-1 with the 3K rice genome (RG) dataset identified …

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Investigation Of Metastable Low Dimensional Halometallates, Navindra Keerthisinghe, Matthew S. Christian, Anna A. Berseneva, Gregory Morrison, Vladislav V. Klepov, Mark D. Smith, Hans Conrad Zur Loye Jan 2022

Investigation Of Metastable Low Dimensional Halometallates, Navindra Keerthisinghe, Matthew S. Christian, Anna A. Berseneva, Gregory Morrison, Vladislav V. Klepov, Mark D. Smith, Hans Conrad Zur Loye

Faculty Publications

The solvothermal synthesis, structure determination and optical characterization of five new metastable halometallate compounds, [1,10-phenH][Pb3.5I8] (1), [1,10-phenH2][Pb5I12]·(H2O) (2), [1,10-phen][Pb2I4] (3), [1,10-phen]2[Pb5Br10] (4) and [1,10-phenH][SbI4]·(H2O) (5), are reported. The materials exhibit rich structural diversity and exhibit structural dimensionalities that include 1D chains, 2D sheets and 3D frameworks. The optical spectra of these materials are consistent with bandgaps ranging from 2.70 to 3.44 eV. We show …

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Structure Of A Monomeric Photosystem Ii Core Complex From A Cyanobacterium Acclimated To Far-Red Light Reveals The Functions Of Chlorophylls D And F, Christopher J. Gisriel, Gaozhong Shen, Ming-Yang Ho, Vasily Kurashov, David A. Flesher Jan 2022

Structure Of A Monomeric Photosystem Ii Core Complex From A Cyanobacterium Acclimated To Far-Red Light Reveals The Functions Of Chlorophylls D And F, Christopher J. Gisriel, Gaozhong Shen, Ming-Yang Ho, Vasily Kurashov, David A. Flesher

Faculty Publications

Far-red light (FRL) photoacclimation in cyanobacteria provides a selective growth advantage for some terrestrial cyanobacteria by expanding the range of photosynthetically active radiation to include far-red/near-infrared light (700-800 nm). During this photoacclimation process, photosystem II (PSII), the water:plastoquinone photooxidoreductase involved in oxygenic photosynthesis, is modified. The resulting FRL-PSII is comprised of FRL-specific core subunits and binds chlorophyll (Chl) d and Chl f molecules in place of several of the Chl a molecules found when cells are grown in visible light. These new Chls effectively lower the energy canonically thought to define the "red limit" for light required to drive photochemical …

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Single-Variable Porous Nanomaterial Series From Polymer Structure-Directing Agents, Morgan Stefik Dec 2021

Single-Variable Porous Nanomaterial Series From Polymer Structure-Directing Agents, Morgan Stefik

Faculty Publications

Block polymer structure-directing agents (SDA) enable the production of porous nanoscale materials. Most strategies rely upon polymer equilibration where diverse morphologies are realized in porous functional materials. This review details how solvent selectivity determines the polymer SDA behaviors, spanning from bulk-type to solution-type. Equilibrating behavior of either type, however, obscures nanostructure cause-and-effect since the resulting sample series convolve multiple spatial variations. Solution-type SDA behaviors include both dynamic and persistent micelles. Persistent micelle templates (PMT) use high solvent selectivity for kinetic entrapment. PMTs enable independent wall thickness control with demonstrated 2 Å precision alterations. Unimodal PMT pore size distributions have spanned …

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Spectroscopic Studies Of The Interaction Between Phosphorus Heterocycles And Cytochrome P450, Dumei Ma, Libo Zhang, Yingwu Yin, Yuxing Gao, Qian Wang Dec 2021

Spectroscopic Studies Of The Interaction Between Phosphorus Heterocycles And Cytochrome P450, Dumei Ma, Libo Zhang, Yingwu Yin, Yuxing Gao, Qian Wang

Faculty Publications

P450 fatty acid decarboxylase OleT from Staphylococcus aureus (OleTSA) is a novel cytochrome P450 enzyme that catalyzes the oxidative decarboxylation of fatty acids to yield primarily terminal alkenes and CO2 or minor α- and β-hydroxylated fatty acids as side-products. In this work, the interactions between a series of cycloalkyl phosphorus heterocycles (CPHs) and OleTSA were investigated in detail by fluorescence titration experiment, ultraviolet–visible (UV–vis) and 31P NMR spectroscopies. Fluorescence titration experiment results clearly showed that a dynamic quenching occurred when CPH-6, a representative CPHs, interacted with OleTSA with a binding constant value of 15.2 …

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Fe-Catalyzed Sulfide Oxidation In Hydrothermal Plumes Is A Source Of Reactive Oxygen Species To The Ocean, Timothy J. Shaw, George W. Luther Iii, Richard Rosas, Véronique E. Oldham, Nicole R. Coffey, John L. Ferry, Dewamunnage M. C. Dias, Mustafa Yücel, Aubin Thibault De Chanvalon Sep 2021

Fe-Catalyzed Sulfide Oxidation In Hydrothermal Plumes Is A Source Of Reactive Oxygen Species To The Ocean, Timothy J. Shaw, George W. Luther Iii, Richard Rosas, Véronique E. Oldham, Nicole R. Coffey, John L. Ferry, Dewamunnage M. C. Dias, Mustafa Yücel, Aubin Thibault De Chanvalon

Faculty Publications

Historically, the production of reactive oxygen species (ROS) in the ocean has been attributed to photochemical and biochemical reactions. However, hydrothermal vents emit globally significant inventories of reduced Fe and S species that should react rapidly with oxygen in bottom water and serve as a heretofore unmeasured source of ROS. Here, we show that the Fe-catalyzed oxidation of reduced sulfur species in hydrothermal vent plumes in the deep oceans supported the abiotic formation of ROS at concentrations 20 to 100 times higher than the average for photoproduced ROS in surface waters. ROS (measured as hydrogen peroxide) were determined in hydrothermal …

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Small Studies, Big Decisions: The Role Of Pilot/Feasibility Studies In Incremental Science And Premature Scale-Up Of Behavioral Interventions, Michael William Beets, Lauren Von Klinggraeff, Robert G. Weaver, Bridget Ryan Armstrong, Sarah Burkart Sep 2021

Small Studies, Big Decisions: The Role Of Pilot/Feasibility Studies In Incremental Science And Premature Scale-Up Of Behavioral Interventions, Michael William Beets, Lauren Von Klinggraeff, Robert G. Weaver, Bridget Ryan Armstrong, Sarah Burkart

Faculty Publications

Background: Careful consideration and planning are required to establish “sufficient” evidence to ensure an investment in a larger, more well-powered behavioral intervention trial is worthwhile. In the behavioral sciences, this process typically occurs where smaller-scale studies inform larger-scale trials. Believing that one can do the same things and expect the same outcomes in a larger-scale trial that were done in a smaller-scale preliminary study (i.e., pilot/feasibility) is wishful thinking, yet common practice. Starting small makes sense, but small studies come with big decisions that can influence the usefulness of the evidence designed to inform decisions about moving forward with a …

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Encirclement Of Moving Targets Using Noisy Range And Bearing Measurements, Cammy Peterson, Puneet Jain, Randal Beard Aug 2021

Encirclement Of Moving Targets Using Noisy Range And Bearing Measurements, Cammy Peterson, Puneet Jain, Randal Beard

Faculty Publications

This paper presents theoretically justified controllers that use relative range and bearing measurements to steer a team of autonomous vehicles, operating without inertial position information, to circular trajectories around a constant-acceleration, constant-velocity, or stationary target. An extended Kalman filter is used to improve the noisy relative measurements and estimate the velocity of the moving target. These estimated values are used in the control laws to encircle constant-velocity moving targets. Lyapunov techniques are utilized to show that the vehicle will converge to the desired circular formations. Additionally, cooperating vehicles are shown to converge to a circular formation with equal temporal spacing …

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Free Three-Dimensional Carborane Carbanions, H.D.A. Zzzchathumal Jayaweera, Md. Mamdudur Rahman, Perry J. Pellechia, Mark D. Smith, Dmitry V. Peryshkov Jun 2021

Free Three-Dimensional Carborane Carbanions, H.D.A. Zzzchathumal Jayaweera, Md. Mamdudur Rahman, Perry J. Pellechia, Mark D. Smith, Dmitry V. Peryshkov

Faculty Publications

Carbon atom functionalization via generation of carbanions is the cornerstone of carborane chemistry. In this work, we report the synthesis and structural characterization of free ortho-carboranyl [C2B10H11]−, a three-dimensional inorganic analog of the elusive phenyl anion that features a “naked” carbanion center. The first example of a stable, discrete C(H)-deprotonated carborane anion was isolated as a completely separated ion pair with a crown ether-encapsulated potassium cation. An analogous approach led to the isolation and structural characterization of a doubly deprotonated 1,1′-bis(o-carborane) anion [C2B10H10] …

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Tailored Porous Carbons Enabled By Persistent Micelles With Glassy Cores, Eric R. Williams, Paige L. Mcmahon, Joseph E. Reynolds Iii, Jonathan L. Snider, Vitalie Stavila, Mark Allendorf, Morgan Stefik Jun 2021

Tailored Porous Carbons Enabled By Persistent Micelles With Glassy Cores, Eric R. Williams, Paige L. Mcmahon, Joseph E. Reynolds Iii, Jonathan L. Snider, Vitalie Stavila, Mark Allendorf, Morgan Stefik

Faculty Publications

Porous nanoscale carbonaceous materials are widely employed for catalysis, separations, and electrochemical devices where device performance often relies upon specific and well-defined regular feature sizes. The use of block polymers as templates has enabled affordable and scalable production of diverse porous carbons. However, popular carbon preparations use equilibrating micelles which can change dimensions in response to the processing environment. Thus, polymer methods have not yet demonstrated carbon nanomaterials with constant average template diameter and tailored wall thickness. In contrast, persistent micelle templates (PMTs) use kinetic control to preserve constant micelle template diameters, and thus PMT has enabled constant pore diameter …

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Host–Guest Interactions In A Metal–Organic Framework Isoreticular Series For Molecular Photocatalytic Co2 Reduction, Philip M. Stanley, Johanna Haimerl, Christopher Thomas, Alexander Urstoeger, Michael Schuster Prof. Dr., Natalia B. Shustova Prof. Dr., Angela Casini Prof. Dr., Bernhard Rieger Prof. Dr., Julien Warnan Dr., Roland A. Fischer Prof. Dr. May 2021

Host–Guest Interactions In A Metal–Organic Framework Isoreticular Series For Molecular Photocatalytic Co2 Reduction, Philip M. Stanley, Johanna Haimerl, Christopher Thomas, Alexander Urstoeger, Michael Schuster Prof. Dr., Natalia B. Shustova Prof. Dr., Angela Casini Prof. Dr., Bernhard Rieger Prof. Dr., Julien Warnan Dr., Roland A. Fischer Prof. Dr.

Faculty Publications

A strategy to improve homogeneous molecular catalyst stability, efficiency, and selectivity is the immobilization on supporting surfaces or within host matrices. Herein, we examine the co-immobilization of a CO2 reduction catalyst [ReBr(CO)3(4,4′-dcbpy)] and a photosensitizer [Ru(bpy)2(5,5′-dcbpy)]Cl2 using the isoreticular series of metal–organic frameworks (MOFs) UiO-66, -67, and -68. Specific host pore size choice enables distinct catalyst and photosensitizer spatial location—either at the outer MOF particle surface or inside the MOF cavities—affecting catalyst stability, electronic communication between reaction center and photosensitizer, and consequently the apparent catalytic rates. These results allow for a rational understanding of an optimized supramolecular layout of catalyst, …

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Beyond Structural Motifs: The Frontier Of Actinide-Containing Metal–Organic Frameworks, Corey R. Martin, Gabrielle A. Leith, Natalia B. Shustova Prof. Dr. May 2021

Beyond Structural Motifs: The Frontier Of Actinide-Containing Metal–Organic Frameworks, Corey R. Martin, Gabrielle A. Leith, Natalia B. Shustova Prof. Dr.

Faculty Publications

In this perspective, we feature recent advances in the field of actinide-containing metal–organic frameworks (An-MOFs) with a main focus on their electronic, catalytic, photophysical, and sorption properties. This discussion deviates from a strictly crystallographic analysis of An-MOFs, reported in several reviews, or synthesis of novel structural motifs, and instead delves into the remarkable potential of An-MOFs for evolving the nuclear waste administration sector. Currently, the An-MOF field is dominated by thorium- and uranium-containing structures, with only a few reports on transuranic frameworks. However, some of the reported properties in the field of An-MOFs foreshadow potential implementation of these materials and …

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Beyond Structural Motifs: The Frontier Of Actinide-Containing Metal–Organic Frameworks, Corey R. Martin, Gabrielle A. Leith, Natalia B. Shustova May 2021

Beyond Structural Motifs: The Frontier Of Actinide-Containing Metal–Organic Frameworks, Corey R. Martin, Gabrielle A. Leith, Natalia B. Shustova

Faculty Publications

In this perspective, we feature recent advances in the field of actinide-containing metal-organic frameworks (An-MOFs) with a main focus on their electronic, catalytic, photophysical, and sorption properties. This discussion deviates from a strictly crystallographic analysis of An-MOFs, reported in several reviews, or synthesis of novel structural motifs, and instead delves into the remarkable potential of An-MOFs for evolving the nuclear waste administration sector. Currently, the An-MOF field is dominated by thorium- and uranium-containing structures, with only a few reports on transuranic frameworks. However, some of the reported properties in the field of An-MOFs foreshadow potential implementation of these materials and …

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The Supercam Instrument Suite On The Mars 2020 Rover: Science Objectives And Mast-Unit Description, S. Maurice, R. C. Wiens, P. Bernardi, P. Caïs, S. Robinson, T. Nelson, O. Gasnault, J. -M. Reess, M. Deleuze, F. Rull, J. -A. Manrique, S. Abbaki, R. B. Anderson, Y. André, Stanley M. Angel, G. Arana, T. Battault, P. Beck, K. Benzerara, S. Bernard, Et. Al. Apr 2021

The Supercam Instrument Suite On The Mars 2020 Rover: Science Objectives And Mast-Unit Description, S. Maurice, R. C. Wiens, P. Bernardi, P. Caïs, S. Robinson, T. Nelson, O. Gasnault, J. -M. Reess, M. Deleuze, F. Rull, J. -A. Manrique, S. Abbaki, R. B. Anderson, Y. André, Stanley M. Angel, G. Arana, T. Battault, P. Beck, K. Benzerara, S. Bernard, Et. Al.

Faculty Publications

On the NASA 2020 rover mission to Jezero crater, the remote determination of the texture, mineralogy and chemistry of rocks is essential to quickly and thoroughly characterize an area and to optimize the selection of samples for return to Earth. As part of the Perseverance payload, SuperCam is a suite of five techniques that provide critical and complementary observations via Laser-Induced Breakdown Spectroscopy (LIBS), Time-Resolved Raman and Luminescence (TRR/L), visible and near-infrared spectroscopy (VISIR), high-resolution color imaging (RMI), and acoustic recording (MIC). SuperCam operates at remote distances, primarily 2–7 m, while providing data at sub-mm to mm scales. We report …

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Broken-Hearted” Carbon Bowl Via Electron Shuttle Reaction: Energetics And Electron Coupling, Gabrielle A. Leith, Allison M. Rice, Brandon J. Yarbrough, Preecha Kittikhunnatham, Abijai Mathur, Nicholas A. Morris, Megan J. Francis, Anna A. Berseneva, Poonam Dhull, Richard D. Adams, M. Victoria Bobo, Aaron A. Vannucci, Mark D. Smith, Sophya Garashchuk, Natalia B. Shustova Apr 2021

Broken-Hearted” Carbon Bowl Via Electron Shuttle Reaction: Energetics And Electron Coupling, Gabrielle A. Leith, Allison M. Rice, Brandon J. Yarbrough, Preecha Kittikhunnatham, Abijai Mathur, Nicholas A. Morris, Megan J. Francis, Anna A. Berseneva, Poonam Dhull, Richard D. Adams, M. Victoria Bobo, Aaron A. Vannucci, Mark D. Smith, Sophya Garashchuk, Natalia B. Shustova

Faculty Publications

Unprecedented one-step CC bond cleavage leading to opening of the buckybowl (π-bowl), that could provide access to carbon-rich structures with previously inaccessible topologies, is reported; highlighting the possibility to implement drastically different synthetic routes to π-bowls in contrast to conventional ones applied for polycyclic aromatic hydrocarbons. Through theoretical modeling, we evaluated the mechanistic pathways feasible for π-bowl planarization and factors that could affect such a transformation including strain and released energies. Through employment of Marcus theory, optical spectroscopy, and crystallographic analysis, we estimated the possibility of charge transfer and electron coupling between “open” corannulene and a strong electron acceptor such …

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