Physical Sciences and Mathematics | Open Access Articles

Transition Metal‐Catalyzed And Mao‐Assisted Olefin Polymerization. Cyclic Isomers Of Sinn’S Dimer Are Excellent Ligands In Iron Complexes And Great Methylating Reagents, Kaidi Yang, Rainer Glaser

Chemistry Faculty Research & Creative Works

Methylaluminoxane (MAO) is the most commonly used co‐catalyst for transition metalcatalyzed olefin polymerization, but the structures of MAO species and their catalytic functions remain topics of intensive study. We are interested in MAO‐assisted polymerization with catalysts L(R₂)FeCl₂ (L = tridentate pyridine‐2,6‐diyldimethanimine; imine‐R = Me, Ph). It is our hypothesis that the MAO species is not merely enabling Fe−Me bond formation but functions as an integral part of the active catalyst, a MAO adduct of the Fe‐precatalyst [L(R₂)FeCl]⁺. In this paper, we explored the possible structures of acyclic and cyclic MAO species and their …

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Thiol Antioxidants Protect Human Lens Epithelial (Hle B-3) Cells Against Tert-Butyl Hydroperoxide-Induced Oxidative Damage And Cytotoxicity, Annalise Pfaff, Anna Chernatynskaya, Hannah Vineyard, Nuran Ercal

Chemistry Faculty Research & Creative Works

Oxidative damage to lens epithelial cells plays an important role in the development of age-related cataract, and the health of the lens has important implications for overall ocular health. As a result, there is a need for effective therapeutic agents that prevent oxidative damage to the lens. Thiol antioxidants such as tiopronin or N-(2-mercaptopropionyl)glycine (MPG), N-acetylcysteine amide (NACA), N-acetylcysteine (NAC), and exogenous glutathione (GSH) may be promising candidates for this purpose, but their ability to protect lens epithelial cells is not well understood. The effectiveness of these compounds was compared by exposing human lens epithelial cells (HLE B-3) to the …

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Noninvasive Detection, Tracking, And Characterization Of Aerogel Implants Using Diagnostic Ultrasound, Sagar Ghimire, Martina Rodriguez Sala, Swetha Chandrasekaran, Grigorios Raptopoulos, Marcus Worsley, Patrina Paraskevopoulou, Nicholas Leventis, Firouzeh Sabri

Chemistry Faculty Research & Creative Works

Medical implants are routinely tracked and monitored using different techniques, such as MRI, X‐ray, and ultrasound. Due to the need for ionizing radiation, the two former methods pose a significant risk to tissue. Ultrasound imaging, however, is non‐invasive and presents no known risk to human tissue. Aerogels are an emerging material with great potential in biomedical implants. While qualitative observation of ultrasound images by experts can already provide a lot of infor-mation about the implants and the surrounding structures, this paper describes the development and study of two simple B‐Mode image analysis techniques based on attenuation measurements and echogenicity comparisons, …

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Multi-Walled Carbon Nanotube Supported Manganese Selenide As A Highly Active Bifunctional Oer And Orr Electrocatalyst, Harish Singh, Mckenzie Marley-Hines, Shatadru Chakravarty, Manashi Nath

Chemistry Faculty Research & Creative Works

Transition metal selenides have attracted intensive interest as cost-effective electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) because of the continuous thrust in sustainable energy conversion. In this article a Mn-based bifunctional electrocatalyst, MnSe, has been identified which shows efficient OER and ORR activity in alkaline medium. The catalytic activity could be further enhanced by using multiwalled carbon nanotubes (MWCNTs) which increases the charge transfer and electronic conductivity of the catalyst composite. This MnSe@MWCNT catalyst composite exhibits a very low overpotential of 290 mV at 10 mA cm⁻², which outperforms state-of-the-art RuO₂ as …

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Epitaxial Electrodeposition Of Hole Transport Cuscn Nanorods On Au(111) At The Wafer Scale And Lift-Off To Produce Flexible And Transparent Foils, Bin Luo, Avishek Banik, Eric W. Bohannan, Jay A. Switzer

Chemistry Faculty Research & Creative Works

The wide bandgap p-type metal pseudohalide semiconductor copper(I) thiocyanate (CuSCN) can serve as a transparent hole transport layer in various opto-electronic applications such as perovsksite and organic solar cells and light-emitting diodes. The material deposits as one-dimensional CuSCN nanorod arrays, which are advantageous due to their high surface area and good charge transport properties. However, the growth of high-quality epitaxial CuSCN nanorods has remained a challenge. Here, we introduce a low cost and highly scalable room temperature procedure for producing epitaxial CuSCN nanorods on Au(111) by an electrochemical method. Epitaxial CuSCN grows on Au(111) with a high degree of in-plane …

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Special Issue: Microbiota-Gut-Brain Axis, Mark Obrenovich, Prakash Reddy

Chemistry Faculty Research & Creative Works

No abstract provided.

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Collisional Excitation And Non-Lte Modeling Of Interstellar Chiral Propylene Oxide, Karlis Dzenis, Alexandre Faure, B. A. Mcguire, A. J. Remijan, P. J. Dagdigian, C. Rist, Richard Dawes, Ernesto Quintas-Sánchez, F. Lique, M. Hochlaf

Chemistry Faculty Research & Creative Works

The first set of theoretical rotational cross sections for propylene oxide (CH₃CHCH₂O) colliding with cold He atoms has been obtained at the full quantum level using a high-accuracy potential energy surface. By scaling the collision reduced mass, rotational rate coefficients for collisions with para-H₂ are deduced in the temperature range 5-30 K. These collisional coefficients are combined with radiative data in a non-LTE radiative transfer model in order to reproduce observations of propylene oxide made toward the Sagittarius B2(N) molecular cloud with the Green Bank and Parkes radio telescopes. The three detected absorption lines are …

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A Novel Branched Polymer Gel System With Delayed Gelation Property For Conformance Control, Tao Song, Qi Feng, Thomas P. Schuman, Jie Cao, Baojun Bai

Chemistry Faculty Research & Creative Works

Excessive water production from oil reservoirs not only affects the economical production of oil, but it also results in serious environmental concerns. Polymer gels have been widely applied to decrease water production and thus improve oil production. However, traditional polymer gels such as partially hydrolyzed polyacrylamide (HPAM)/chromium (III) gel systems usually have a short gelation time and cannot meet the requirement of some conformance control projects. This paper introduces a novel polymer gel system of which crosslinking time can be significantly delayed. A branched polymer grafted from arginine by the surface initiation method is synthesized as the backbone, chromium acetate …

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Collisional Excitation And Non-Lte Modeling Of Interstellar Chiral Propylene Oxide, Karlis Dzenis, Alexandre Faure, B. A. Mcguire, A. J. Remijan, P. J. Dagdigian, C. Rist, Richard Dawes, Ernesto Quintas-Sánchez, F. Lique, M. Hochlaf

Chemistry Faculty Research & Creative Works

The first set of theoretical rotational cross sections for propylene oxide (CH₃CHCH₂O) colliding with cold He atoms has been obtained at the full quantum level using a high-accuracy potential energy surface. By scaling the collision reduced mass, rotational rate coefficients for collisions with para-H2 are deduced in the temperature range 5-30 K. These collisional coefficients are combined with radiative data in a non-LTE radiative transfer model in order to reproduce observations of propylene oxide made toward the Sagittarius B2(N) molecular cloud with the Green Bank and Parkes radio telescopes. The three detected absorption lines are found …

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Noninvasive Detection, Tracking, And Characterization Of Aerogel Implants Using Diagnostic Ultrasound, Sagar Ghimire, Martina Rodriguez Sala, Swetha Chandrasekaran, Grigorios Raptopoulos, Marcus Worsley, Patrina Paraskevopoulou, Nicholas Leventis, Firouzeh Sabri

Chemistry Faculty Research & Creative Works

Medical implants are routinely tracked and monitored using different techniques, such as MRI, X‐ray, and ultrasound. Due to the need for ionizing radiation, the two former methods pose a significant risk to tissue. Ultrasound imaging, however, is non‐invasive and presents no known risk to human tissue. Aerogels are an emerging material with great potential in biomedical implants. While qualitative observation of ultrasound images by experts can already provide a lot of infor-mation about the implants and the surrounding structures, this paper describes the development and study of two simple B‐Mode image analysis techniques based on attenuation measurements and echogenicity comparisons, …

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Special Issue: Microbiota–Gut–Brain Axis, Mark Obrenovich, V. (Prakash) Reddy

Chemistry Faculty Research & Creative Works

No abstract provided.

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The Molecular Structure And Curious Motions In 1,1-Difluorosilacyclopent-3-Ene And Silacyclopent-3-Ene As Determined By Microwave Spectroscopy And Quantum Chemical Calculations, Thomas M.C. Mcfadden, Nicole Moon, Frank E. Marshall, Amanda J. Duerden, Esther J. Ocola, Jaan Laane, Gamil A. Guirgis, Garry S. Grubbs

Chemistry Faculty Research & Creative Works

The molecules 1,1-difluorosilacyclopent-3-ene (3SiCPF2) and silacyclopent-3-ene (3SiCP) have been synthesized and studied using chirped pulse, Fourier transform microwave (CP-FTMW) spectroscopy. For 3SiCP this is the first ever microwave study of the molecule and, for 3SiCPF2, the spectra reported in this work have been combined with that of previous work in a global fit. The spectra of each contain splitting which has been fit using a Hamiltonian consisting of semirigid and Coriolis coupling parameters. A refit of the original 3SiCPF2 work was also carried out. All fits and approaches are reported. Analyses of the spectra provide evidence that the molecule is …

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Polybenzodiazine Aerogels: All-Nitrogen Analogues Of Polybenzoxazines Synthesis, Characterization, And High-Yield Conversion To Nanoporous Carbons, Vaibhav A. Edlabadkar, Saidulu Gorla, Rushi U. Soni, A. B.M.Shaheen Ud Doulah, Joseph Gloriod, Samuel Hackett, Nicholas Leventis, Chariklia Sotiriou-Leventis

Chemistry Faculty Research & Creative Works

Tetrahydroquinazoline (THQ) was designed as an all-nitrogen analogue of main-stream benzoxazine monomers. THQ solutions in DMF gelled at 100 °C via HCl-catalyzed ring-opening polymerization to polybenzodiazine (PBDAZ) wet gels, which were dried in an autoclave with supercritical fluid CO₂ to aerogels. These as-prepared PBDAZ-100 aerogels undergo ring-fusion aromatization at 240 °C under O₂. This oxidized form is referred to as PBDAZ-240. Chemical identification of PBDAZ-100 and PBDAZ-240 relied on consideration of all nine possible polymerization pathways, in combination with elemental analysis, infrared and solid-state 13C NMR spectroscopy, and 15N NMR spectroscopy of aerogels from the selectively 15N-enriched …

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Full-Text Articles in Physical Sciences and Mathematics

Transition Metal‐Catalyzed And Mao‐Assisted Olefin Polymerization. Cyclic Isomers Of Sinn’S Dimer Are Excellent Ligands In Iron Complexes And Great Methylating Reagents, Kaidi Yang, Rainer Glaser

Chemistry Faculty Research & Creative Works

Thiol Antioxidants Protect Human Lens Epithelial (Hle B-3) Cells Against Tert-Butyl Hydroperoxide-Induced Oxidative Damage And Cytotoxicity, Annalise Pfaff, Anna Chernatynskaya, Hannah Vineyard, Nuran Ercal

Chemistry Faculty Research & Creative Works

Noninvasive Detection, Tracking, And Characterization Of Aerogel Implants Using Diagnostic Ultrasound, Sagar Ghimire, Martina Rodriguez Sala, Swetha Chandrasekaran, Grigorios Raptopoulos, Marcus Worsley, Patrina Paraskevopoulou, Nicholas Leventis, Firouzeh Sabri

Chemistry Faculty Research & Creative Works

Multi-Walled Carbon Nanotube Supported Manganese Selenide As A Highly Active Bifunctional Oer And Orr Electrocatalyst, Harish Singh, Mckenzie Marley-Hines, Shatadru Chakravarty, Manashi Nath

Chemistry Faculty Research & Creative Works

Epitaxial Electrodeposition Of Hole Transport Cuscn Nanorods On Au(111) At The Wafer Scale And Lift-Off To Produce Flexible And Transparent Foils, Bin Luo, Avishek Banik, Eric W. Bohannan, Jay A. Switzer

Chemistry Faculty Research & Creative Works

Special Issue: Microbiota-Gut-Brain Axis, Mark Obrenovich, Prakash Reddy

Chemistry Faculty Research & Creative Works

Collisional Excitation And Non-Lte Modeling Of Interstellar Chiral Propylene Oxide, Karlis Dzenis, Alexandre Faure, B. A. Mcguire, A. J. Remijan, P. J. Dagdigian, C. Rist, Richard Dawes, Ernesto Quintas-Sánchez, F. Lique, M. Hochlaf

Chemistry Faculty Research & Creative Works

A Novel Branched Polymer Gel System With Delayed Gelation Property For Conformance Control, Tao Song, Qi Feng, Thomas P. Schuman, Jie Cao, Baojun Bai

Chemistry Faculty Research & Creative Works

Collisional Excitation And Non-Lte Modeling Of Interstellar Chiral Propylene Oxide, Karlis Dzenis, Alexandre Faure, B. A. Mcguire, A. J. Remijan, P. J. Dagdigian, C. Rist, Richard Dawes, Ernesto Quintas-Sánchez, F. Lique, M. Hochlaf

Chemistry Faculty Research & Creative Works

Noninvasive Detection, Tracking, And Characterization Of Aerogel Implants Using Diagnostic Ultrasound, Sagar Ghimire, Martina Rodriguez Sala, Swetha Chandrasekaran, Grigorios Raptopoulos, Marcus Worsley, Patrina Paraskevopoulou, Nicholas Leventis, Firouzeh Sabri

Chemistry Faculty Research & Creative Works

Special Issue: Microbiota–Gut–Brain Axis, Mark Obrenovich, V. (Prakash) Reddy

Chemistry Faculty Research & Creative Works

Chemistry Faculty Research & Creative Works

Chemistry Faculty Research & Creative Works