Physical Sciences and Mathematics Commons^™

Helium Nanodroplets As An Efficient Tool To Investigate Hydrogen Attachment To Alkali Cations, Siegfried Kollotzek, José Campos-Martínez, Massimiliano Bartolomei, Fernando Pirani, Lukas Tiefenthaler, Marta I. Hernández, Teresa Lázaro, Eva Zunzunegui-Bru, Tomás González-Lezana, José Bretón, Javier Hernández-Rojas, Olof E. Echt, Paul Scheier

Faculty Publications

We report a novel method to reversibly attach and detach hydrogen molecules to positively charged sodium clusters formed inside a helium nanodroplet host matrix. It is based on the controlled production of multiply charged helium droplets which, after picking up sodium atoms and exposure to H₂ vapor, lead to the formation of Na_m⁺(H₂)_n clusters, whose population was accurately measured using a time-of-flight mass spectrometer. The mass spectra reveal particularly favorable Na⁺(H₂)_n and Na₂⁺(H₂)_n clusters for specific “magic” numbers of attached hydrogen molecules. …

A Molecular Chemodosimeter To Probe “Closed Shell” Ions In Kidney Cells, Rashid Mia

Faculty Publications

Two quinidine-functionalized coumarin molecular probes have been synthesized and have been found to bind metal cations (Cd2+, Co2+, Cu2+, Fe2+, Hg2+, Ni2+, and Zn2+) with high affinity in organic–aqueous media (DMSO–HEPES). The chemodosimeters coordinate with the Zn2+ ions in a two-to-one ratio (molecular probe : Zn2+) with a log β of 10.0 M−2. Upon the addition of the closed-shell metal ions studied, a fluorescence turn-on via an excimer formation is seen at 542 nm due to the quinaldine moiety adopting a syn arrangement when coordinated to the metal Zn2+ ions. Confocal microscopy monitored free Zn2+ ions in the Human Embryonic …

Solvation Of Large Polycyclic Aromatic Hydrocarbons In Helium: Cationic And Anionic Hexabenzocoronene, Miriam Kappe, Florent Calvo, Johannes Schöntag, Holger F. Bettinger, Serge Krasnokutski, Martin Kuhn, Elisabeth Gruber, Fabio Zappa, Paul Scheier, Olof E. Echt

Faculty Publications

The adsorption of helium on charged hexabenzocoronene (Hbc, C₄₂H₁₈), a planar polycyclic aromatic hydrocarbon (PAH) molecule of D_6h symmetry, is investigated by a combination of high-resolution mass spectrometry and classical and quantum computational methods. The ion abundance of He_nHbc⁺ complexes versus size n features prominent local anomalies at n = 14, 38, 68, 82, and a weak one at 26, indicating that for these “magic” sizes the helium evaporation energies are relatively large. Surprisingly, mass spectra of anionic He_nHbc^– complexes feature a different set of anomalies, namely at …

Adsorption Of Helium And Hydrogen On Triphenylene And 1,3,5-Triphenylbenzene, Bergmeister Bergmeister, Kollotzek Kollotzek, Florent Calvo, Elisabeth Gruber, Fabio Zappa, Paul Scheier, Olof E. Echt

Faculty Publications

The adsorption of helium or hydrogen on cationic triphenylene (TPL, C₁₈H₁₂), a planar polycyclic aromatic hydrocarbon (PAH) molecule, and of helium on cationic 1,3,5-triphenylbenzene (TPB, C₂₄H₁₈), a propeller-shaped PAH, is studied by a combination of high-resolution mass spectrometry and classical and quantum computational methods. Mass spectra indicate that He_nTPL⁺ complexes are particularly stable if n = 2 or 6, in good agreement with the quantum calculations which show that for these sizes the helium atoms are strongly localized on either side of the central carbon ring for n = …

Invigorating Seventh-Day Adventist Science Education With Chemical Knowledge Of God's Creation, Ryan T. Hayes, D. David Nowack

Faculty Publications

No abstract provided.

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 …

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 …

Luminescence And Scintillation In The Niobium Doped Oxyfluoride Rb4Ge5O9F6:Nb, Darrone 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 synthe-sized in single crystal form by high-temperature flux growth. The host structure, Rb4Ge5O9F6, crystal-lizes in the orthorhombic space groupPbcnwith lattice parametersa= 6.98430(10)Å,b= 11.7265(2) Å,andc= 19.2732(3) Å, consisting of germanium oxyfluoride layers made up of Ge3O9units connectedby GeO3F3octahedra. In its pure form, Rb4Ge5O9F6shows neither luminescence nor scintillation butwhen doped with niobium, Rb4Ge5O9F6:Nb exhibits bright blue luminescence and scintillation. Theisostructural doped structure, Rb4Ge5O9F6:Nb, crystallizes in the orthorhombic space groupPbcnwith lattice parametersa= 6.9960(3) Å,b= 11.7464(6) Å, andc= 19.3341(9) Å. X-ray absorption nearedge structure (XANES) and extended X-ray absorption fine structure (EXAFS) measurements suggestthat the niobium …

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 …

Stabilization Of Phenanthrene Anions In Helium Nanodroplets, Siegfried Kollotzek, Farhad Izadi, Miriam Meyer, Stefan Bergmeister, Fabio Zappa, Stephan Denifl, Olof E. Echt, Paul Scheier, Elisabeth Gruber

Faculty Publications

It has been debated for years if the polycyclic aromatic hydrocarbon phenanthrene exists in its anionic form, or, in other words, if its electron affinity (EA) is positive or negative. In this contribution we confirm that the bare phenanthrene anion Ph^- created in a binary collision with an electron at room temperature has a lifetime shorter than microseconds. However, the embedding of neutral phenanthrene molecules in negatively charged helium nanodroplets enables the formation of phenanthrene anions by charge transfer processes and the stabilization of the latter in the ultracold environment. Gentle shrinking of the helium matrix of phenanthrene-doped HNDs …

Hands-On Stem: Chemistry, Physics, And Other Science Resources For K-12 Education, Lisa Ahlberg, G. Brendan Cross

Faculty Publications

No abstract provided.

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 frequency^2,3 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 …

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 …

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).

Phenanthrene: Establishing Lower And Upper Bounds To The Binding Energy Of A Very Weakly Bound Anion, Elisabeth Gruber, Siegfried Kollotzek, Stefan Bergmeister, Fabio Zappa, Milan Ončák, Paul Scheier, Olof E. Echt

Faculty Publications

Quite a few molecules do not form stable anions that survive the time needed for their detection; their electron affinities (EA) are either very small or negative. How does one measure the EA if the anion cannot be observed? Or, at least, can one establish lower and upper bounds to their EA? We propose two approaches that provide lower and upper bounds. We choose the phenanthrene (Ph) molecule whose EA is controversial. Through competition between helium evaporation and electron detachment in He_nPh^- clusters, formed in helium nanodroplets, we estimate the lower bound of the vertical detachment energy …

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 …

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. …

A Survey Of Blind Modulation Classification Techniques For Ofdm Signals, Anand Kumar, Sudhan Majhi, Guan Gui, Hsiao-Chun Wu, Chau Yuen

Faculty Publications

Blind modulation classification (MC) is an integral part of designing an adaptive or intelligent transceiver for future wireless communications. Blind MC has several applications in the adaptive and automated systems of sixth generation (6G) communications to improve spectral efficiency and power efficiency, and reduce latency. It will become a integral part of intelligent software-defined radios (SDR) for future communication. In this paper, we provide various MC techniques for orthogonal frequency division multiplexing (OFDM) signals in a systematic way. We focus on the most widely used statistical and machine learning (ML) models and emphasize their advantages and limitations. The statistical-based blind …

A Survey Of Blind Modulation Classification Techniques For Ofdm Signals, Anand Kumar, Sudhan Majhi, Guan Gui, Hsiao-Chun Wu, Chau Yuen

Faculty Publications

Blind modulation classification (MC) is an integral part of designing an adaptive or intelligent transceiver for future wireless communications. Blind MC has several applications in the adaptive and automated systems of sixth generation (6G) communications to improve spectral efficiency and power efficiency, and reduce latency. It will become a integral part of intelligent software-defined radios (SDR) for future communication. In this paper, we provide various MC techniques for orthogonal frequency division multiplexing (OFDM) signals in a systematic way. We focus on the most widely used statistical and machine learning (ML) models and emphasize their advantages and limitations. The statistical-based blind …

Search Full Text Options Here 3 Of 3 Heat-Mitigated Design And Lorentz Force-Based Steering Of An Mri-Driven Microcatheter Toward Minimally Invasive Surgery, Martin Francis Phelan Iii, Mehmet Efe Tiryaki, Jelena Lazovic, Hunter Gilbert, Metin Sitti

Faculty Publications

Catheters integrated with microcoils for electromagnetic steering under the high, uniform magnetic field within magnetic resonance (MR) scanners (3-7 Tesla) have enabled an alternative approach for active catheter operations. Achieving larger ranges of tip motion for Lorentz force-based steering have previously been dependent on using high power coupled with active cooling, bulkier catheter designs, or introducing additional microcoil sets along the catheter. This work proposes an alternative approach using a heat-mitigated design and actuation strategy for a magnetic resonance imaging (MRI)-driven microcatheter. A quad-configuration microcoil (QCM) design is introduced, allowing miniaturization of existing MRI-driven, Lorentz force-based catheters down to 1-mm …

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][Pb_3.5I₈] (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 …

From Balancing Redox Reactions To Determining Change Of Oxidation Numbers, Pong Kau Yuen, Cheng Man Diana Lau

Faculty Publications

Redox reaction is a core concept in teaching and learning chemistry. This article explores a new method for balancing organic redox reactions that requires the balancing of both atoms and charges. The H+, O, H2O, and e– are used as balanced vehicles in two half reactions. A non-oxidation number approach can be applied to both molecular and ionic equations. The article also provides standard operating procedures and examples. The number of transferred electrons is first determined by balancing a half redox reaction; consequently; the change of oxidation numbers can be calculated. The mathematical equation of Te– = n Te– = …

The Other Legacy Of Qasim Amin: The View From 1908, Hoda Yousef

Faculty Publications

No abstract provided.

Toward Liquid Cell Quantum Sensing: Ytterbium Complexes With Ultra-Narrow Absorption, Ashley J. Shin, Changling Zhao, Yi Shen, Claire E. Dickerson, Timothy Luke Atallah

Faculty Publications

No abstract provided.