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Full-Text Articles in Chemistry

Synthesis And Characterization Of D5-Barbarin For Use In Barbarin-Related Research, Sucheta Kudrimoti, Jacob Machin, Adedamola S. Arojojoye, Samuel G. Awuah, Rodney Eisenberg, Clara Fenger, George Maylin, Andreas F. Lehner, Thomas Tobin Aug 2022

Synthesis And Characterization Of D5-Barbarin For Use In Barbarin-Related Research, Sucheta Kudrimoti, Jacob Machin, Adedamola S. Arojojoye, Samuel G. Awuah, Rodney Eisenberg, Clara Fenger, George Maylin, Andreas F. Lehner, Thomas Tobin

Maxwell H. Gluck Equine Research Center Faculty Publications

Based on structural similarities and equine administration experiments, Barbarin, 5-phenyl-2-oxazolidinethione from Brassicaceae plants, is a possible source of equine urinary identifications of aminorex, (R,S)-5-phenyl-4,5-dihydro-1,3-oxazol-2-amine, an amphetamine-related US Drug Enforcement Administration (DEA) controlled substance considered illegal in sport horses. We now report the synthesis and certification of d5-barbarin to facilitate research on the relationship between plant barbarin and such aminorex identifications. D5-barbarin synthesis commenced with production of d5-2-oxo-2-phenylacetaldehyde oxime (d5-oxime) from d5-acetophenone via butylnitrite in an ethoxide/ethanol solution. This d5-oxime was then reduced with lithium aluminum …


Characteristics And Assessing Biological Risks Of Airborne Bacteria In Waste Sorting Plant, Abbas Norouzian Baghani, Somayeh Golbaz, Gholamreza Ebrahimzadeh, Marcelo I. Guzman, Mahdieh Delikhoon, Mehdi Jamshidi Rastani, Abdullah Barkhordari, Ramin Nabizadeh Feb 2022

Characteristics And Assessing Biological Risks Of Airborne Bacteria In Waste Sorting Plant, Abbas Norouzian Baghani, Somayeh Golbaz, Gholamreza Ebrahimzadeh, Marcelo I. Guzman, Mahdieh Delikhoon, Mehdi Jamshidi Rastani, Abdullah Barkhordari, Ramin Nabizadeh

Chemistry Faculty Publications

Examining the concentration and types of airborne bacteria in waste paper and cardboard sorting plants (WPCSP) is an urgent matter to inform policy makers about the health impacts on exposed workers. Herein, we collected 20 samples at 9 points of a WPCSP every 6 winter days, and found that the most abundant airborne bacteria were positively and negatively correlated to relative humidity and temperature, respectively. The most abundant airborne bacteria (in units of CFU m−3) were: Staphylococcus sp. (72.4) > Micrococcus sp. (52.2) > Bacillus sp. (30.3) > Enterococcus sp. (24.0) > Serratia marcescens (20.1) > E. coli (19.1) > Pseudomonas sp. (16.0) > Nocardia …


Ppld Is A De-N-Acetylase Of The Cell Wall Linkage Unit Of Streptococcal Rhamnopolysaccharides, Jeffrey S. Rush, Prakash Parajuli, Alessandro Ruda, Jian Li, Amol Arunrao Pohane, Svetlana Zamakhaeva, Mohammad M. Rahman, Jennifer C. Chang, Artemis Gogos, Cameron W. Kenner, Gérard Lambeau, Michael J. Federle, Konstantin V. Korotkov, Göran Widmalm, Natalia Korotkova Feb 2022

Ppld Is A De-N-Acetylase Of The Cell Wall Linkage Unit Of Streptococcal Rhamnopolysaccharides, Jeffrey S. Rush, Prakash Parajuli, Alessandro Ruda, Jian Li, Amol Arunrao Pohane, Svetlana Zamakhaeva, Mohammad M. Rahman, Jennifer C. Chang, Artemis Gogos, Cameron W. Kenner, Gérard Lambeau, Michael J. Federle, Konstantin V. Korotkov, Göran Widmalm, Natalia Korotkova

Molecular and Cellular Biochemistry Faculty Publications

The cell wall of the human bacterial pathogen Group A Streptococcus (GAS) consists of peptidoglycan decorated with the Lancefield group A carbohydrate (GAC). GAC is a promising target for the development of GAS vaccines. In this study, employing chemical, compositional, and NMR methods, we show that GAC is attached to peptidoglycan via glucosamine 1-phosphate. This structural feature makes the GAC-peptidoglycan linkage highly sensitive to cleavage by nitrous acid and resistant to mild acid conditions. Using this characteristic of the GAS cell wall, we identify PplD as a protein required for deacetylation of linkage N-acetylglucosamine (GlcNAc). X-ray structural analysis indicates …


Metabolic Features Of Brain Function With Relevance To Clinical Features Of Alzheimer And Parkinson Diseases, David Allan Butterfield, Maria Favia, Iolanda Spera, Annalisa Campanella, Martina Lanza, Alessandra Castegna Jan 2022

Metabolic Features Of Brain Function With Relevance To Clinical Features Of Alzheimer And Parkinson Diseases, David Allan Butterfield, Maria Favia, Iolanda Spera, Annalisa Campanella, Martina Lanza, Alessandra Castegna

Chemistry Faculty Publications

Brain metabolism is comprised in Alzheimer’s disease (AD) and Parkinson’s disease (PD). Since the brain primarily relies on metabolism of glucose, ketone bodies, and amino acids, aspects of these metabolic processes in these disorders—and particularly how these altered metabolic processes are related to oxidative and/or nitrosative stress and the resulting damaged targets—are reviewed in this paper. Greater understanding of the decreased functions in brain metabolism in AD and PD is posited to lead to potentially important therapeutic strategies to address both of these disorders, which cause relatively long-lasting decreased quality of life in patients.


Mansouramycins E–G, Cytotoxic Isoquinolinequinones From Marine Streptomycetes, Mohamed Shaaban, Khaled A. Shaaban, Gerhard Kelter, Heinz Herbert Fiebig, Hartmut Laatsch Dec 2021

Mansouramycins E–G, Cytotoxic Isoquinolinequinones From Marine Streptomycetes, Mohamed Shaaban, Khaled A. Shaaban, Gerhard Kelter, Heinz Herbert Fiebig, Hartmut Laatsch

Center for Pharmaceutical Research and Innovation Faculty Publications

Chemical investigation of the ethyl acetate extract from the marine-derived Streptomyces sp. isolate B1848 resulted in three new isoquinolinequinone derivatives, the mansouramycins E–G (1a–3a), in addition to the previously reported mansouramycins A (5) and D (6). Their structures were elucidated by computer-assisted interpretation of 1D and 2D NMR spectra, high-resolution mass spectrometry, and by comparison with related compounds. Cytotoxicity profiling of the mansouramycins in a panel of up to 36 tumor cell lines indicated a significant cytotoxicity and good tumor selectivity for mansouramycin F (2a), while the activity profile of E ( …


Aberrant Crosstalk Between Insulin Signaling And Mtor In Young Down Syndrome Individuals Revealed By Neuronal-Derived Extracellular Vesicles, Marzia Perluigi, Anna Picca, Elita Montanari, Riccardo Calvani, Federico Marini, Roberto Matassa, Antonella Tramutola, Alberto Villani, Giuseppe Familiari, Fabio Di Domenico, D. Allan Butterfield, Kenneth J. Oh, Emanuele Marzetti, Diletta Valentini, Eugenio Barone Nov 2021

Aberrant Crosstalk Between Insulin Signaling And Mtor In Young Down Syndrome Individuals Revealed By Neuronal-Derived Extracellular Vesicles, Marzia Perluigi, Anna Picca, Elita Montanari, Riccardo Calvani, Federico Marini, Roberto Matassa, Antonella Tramutola, Alberto Villani, Giuseppe Familiari, Fabio Di Domenico, D. Allan Butterfield, Kenneth J. Oh, Emanuele Marzetti, Diletta Valentini, Eugenio Barone

Chemistry Faculty Publications

INTRODUCTION: Intellectual disability, accelerated aging, and early-onset Alzheimer-like neurodegeneration are key brain pathological features of Down syndrome (DS). Although growing research aims at the identification of molecular pathways underlying the aging trajectory of DS population, data on infants and adolescents with DS are missing.

METHODS: Neuronal-derived extracellular vesicles (nEVs) were isolated form healthy donors (HDs, n = 17) and DS children (n = 18) from 2 to 17 years of age and nEV content was interrogated for markers of insulin/mTOR pathways.

RESULTS: nEVs isolated from DS children were characterized by a significant increase in pIRS1Ser636, a marker of …


Premade Nanoparticle Films For The Synthesis Of Vertically Aligned Carbon Nanotubes, Abdul Hoque, Ahamed Ullah, Beth S. Guiton, Noe T. Alvarez Nov 2021

Premade Nanoparticle Films For The Synthesis Of Vertically Aligned Carbon Nanotubes, Abdul Hoque, Ahamed Ullah, Beth S. Guiton, Noe T. Alvarez

Chemistry Faculty Publications

Carbon nanotubes (CNTs) offer unique properties that have the potential to address multiple issues in industry and material sciences. Although many synthesis methods have been developed, it remains difficult to control CNT characteristics. Here, with the goal of achieving such control, we report a bottom-up process for CNT synthesis in which monolayers of premade aluminum oxide (Al2O3) and iron oxide (Fe3O4) nanoparticles were anchored on a flat silicon oxide (SiO2) substrate. The nanoparticle dispersion and monolayer assembly of the oleic-acid-stabilized Al2O3 nanoparticles were achieved using 11-phosphonoundecanoic acid …


Biotinylation As A Tool To Enhance The Uptake Of Small Molecules In Gram-Negative Bacteria, Ankit Pandeya, Ling Yang, Olaniyi Alegun, Chamikara Karunasena, Chad Risko, Zhenyu Li, Yinan Wei Nov 2021

Biotinylation As A Tool To Enhance The Uptake Of Small Molecules In Gram-Negative Bacteria, Ankit Pandeya, Ling Yang, Olaniyi Alegun, Chamikara Karunasena, Chad Risko, Zhenyu Li, Yinan Wei

Chemistry Faculty Publications

Antibiotic resistance is a major public health concern. The shrinking selection of effective antibiotics and lack of new development is making the situation worse. Gram-negative bacteria more specifically pose serious threat because of their double layered cell envelope and effective efflux systems, which is a challenge for drugs to penetrate. One promising approach to breach this barrier is the “Trojan horse strategy”. In this technique, an antibiotic molecule is conjugated with a nutrient molecule that helps the antibiotic to enter the cell through dedicated transporters for the nutrient. Here, we explored the approach using biotin conjugation with a florescent molecule …


Hydrocracking Of Octacosane And Cobalt Fischer–Tropsch Wax Over Nonsulfided Nimo And Pt-Based Catalysts, Wenping Ma, Jungshik Kang, Gary Jacobs, Shelley D. Hopps, Burtron H. Davis Sep 2021

Hydrocracking Of Octacosane And Cobalt Fischer–Tropsch Wax Over Nonsulfided Nimo And Pt-Based Catalysts, Wenping Ma, Jungshik Kang, Gary Jacobs, Shelley D. Hopps, Burtron H. Davis

Center for Applied Energy Research Faculty and Staff Publications

The effect of activation environment (N2, H2 and H2S/H2) on the hydrocracking performance of a NiMo/Al catalyst was studied at 380 °C and 3.5 MPa using octacosane (C28). The catalyst physical structure and acidity were characterized by BET, XRD, SEM-EDX and FTIR techniques. The N2 activation generated more active nonsulfided NiMo/Al catalyst relative to the H2 or H2S activation (XC28, 70–80% versus 6–10%). For a comparison, a NiMo/Si-Al catalyst was also tested after normal H2 activation and showed higher activity at the same process …


Metal-Free Domino Amination-Knoevenagel Condensation Approach To Access New Coumarins As Potent Nanomolar Inhibitors Of Vegfr-2 And Egfr, Essam M. Eliwa, Marcel Frese, Ahmed H. Halawa, Maha M. Soltan, Larissa V. Ponomareva, Jon S. Thorson, Khaled A. Shaaban, Mohamed Shaaban, Ahmed M. El-Agrody, Norbert Sewald Sep 2021

Metal-Free Domino Amination-Knoevenagel Condensation Approach To Access New Coumarins As Potent Nanomolar Inhibitors Of Vegfr-2 And Egfr, Essam M. Eliwa, Marcel Frese, Ahmed H. Halawa, Maha M. Soltan, Larissa V. Ponomareva, Jon S. Thorson, Khaled A. Shaaban, Mohamed Shaaban, Ahmed M. El-Agrody, Norbert Sewald

Center for Pharmaceutical Research and Innovation Faculty Publications

A metal-free, atom-economy and simple work-up domino amination-Knoevenagel condensation approach to construct new coumarin analogous (4a-f and 8a-e) was described. Further, new formyl (5a,d-f) and nitro (9a,d-f) coumarin derivatives were synthesized via C-N coupling reaction of various cyclic secondary amines and 4-chloro-3-(formyl-/nitro)coumarins (1a,c), respectively. The confirmed compounds were screened for their in vitro anti-proliferative activity against KB-3-1, A549 and PC3 human cancer cell lines using resazurin cellular-based assay. Among them, coumarin derivatives 4e and 8e displayed the best anti-cervical cancer potency (KB-3-1) with IC50 values of 15.5 ± 3.54 …


Neuron-Derived Extracellular Vesicles Modulate Microglia Activation And Function, Hui Peng, Brock T. Harvey, Christopher I. Richards, Kimberly Nixon Sep 2021

Neuron-Derived Extracellular Vesicles Modulate Microglia Activation And Function, Hui Peng, Brock T. Harvey, Christopher I. Richards, Kimberly Nixon

Pharmaceutical Sciences Faculty Publications

Microglia act as the immune cells of the central nervous system (CNS). They play an important role in maintaining brain homeostasis but also in mediating neuroimmune responses to insult. The interactions between neurons and microglia represent a key process for neuroimmune regulation and subsequent effects on CNS integrity. However, the molecular mechanisms of neuron-glia communication in regulating microglia function are not fully understood. One recently described means of this intercellular communication is via nano-sized extracellular vesicles (EVs) that transfer a large diversity of molecules between neurons and microglia, such as proteins, lipids, and nucleic acids. To determine the effects of …


Aqueous Photochemistry Of 2-Oxocarboxylic Acids: Evidence, Mechanisms, And Atmospheric Impact, Marcelo I. Guzman, Alexis J. Eugene Aug 2021

Aqueous Photochemistry Of 2-Oxocarboxylic Acids: Evidence, Mechanisms, And Atmospheric Impact, Marcelo I. Guzman, Alexis J. Eugene

Chemistry Faculty Publications

Atmospheric organic aerosols play a major role in climate, demanding a better understanding of their formation mechanisms by contributing multiphase chemical reactions with the participation of water. The sunlight driven aqueous photochemistry of small 2-oxocarboxylic acids is a potential major source of organic aerosol, which prompted the investigations into the mechanisms of glyoxylic acid and pyruvic acid photochemistry reviewed here. While 2-oxocarboxylic acids can be contained or directly created in the particles, the majorities of these abundant and available molecules are in the gas phase and must first undergo the surface uptake process to react in, and on the surface, …


Insight Into The Acrab-Tolc Complex Assembly Process Learned From Competition Studies, Prasangi Rajapaksha, Isoiza Ojo, Ling Yang, Ankit Pandeya, Thilini Abeywansha, Yinan Wei Jul 2021

Insight Into The Acrab-Tolc Complex Assembly Process Learned From Competition Studies, Prasangi Rajapaksha, Isoiza Ojo, Ling Yang, Ankit Pandeya, Thilini Abeywansha, Yinan Wei

Chemistry Faculty Publications

The RND family efflux pump AcrAB-TolC in E. coli and its homologs in other Gram-negative bacteria are major players in conferring multidrug resistance to the cells. While the structure of the pump complex has been elucidated with ever-increasing resolution through crystallography and Cryo-EM efforts, the dynamic assembly process remains poorly understood. Here, we tested the effect of overexpressing functionally defective pump components in wild type E. coli cells to probe the pump assembly process. Incorporation of a defective component is expected to reduce the efflux efficiency of the complex, leading to the so called “dominant negative” effect. Being one of …


Awegnn: Auto-Parametrized Weighted Element-Specific Graph Neural Networks For Molecules., Timothy Szocinski, Duc Duy Nguyen, Guo-Wei Wei Jul 2021

Awegnn: Auto-Parametrized Weighted Element-Specific Graph Neural Networks For Molecules., Timothy Szocinski, Duc Duy Nguyen, Guo-Wei Wei

Mathematics Faculty Publications

While automated feature extraction has had tremendous success in many deep learning algorithms for image analysis and natural language processing, it does not work well for data involving complex internal structures, such as molecules. Data representations via advanced mathematics, including algebraic topology, differential geometry, and graph theory, have demonstrated superiority in a variety of biomolecular applications, however, their performance is often dependent on manual parametrization. This work introduces the auto-parametrized weighted element-specific graph neural network, dubbed AweGNN, to overcome the obstacle of this tedious parametrization process while also being a suitable technique for automated feature extraction on these internally complex …


Donnan Potential Across The Outer Membrane Of Gram-Negative Bacteria And Its Effect On The Permeability Of Antibiotics, Olaniyi Alegun, Ankit Pandeya, Jian Cui, Isoiza Ojo, Yinan Wei Jun 2021

Donnan Potential Across The Outer Membrane Of Gram-Negative Bacteria And Its Effect On The Permeability Of Antibiotics, Olaniyi Alegun, Ankit Pandeya, Jian Cui, Isoiza Ojo, Yinan Wei

Chemistry Faculty Publications

The cell envelope structure of Gram-negative bacteria is unique, composed of two lipid bilayer membranes and an aqueous periplasmic space sandwiched in between. The outer membrane constitutes an extra barrier to limit the exchange of molecules between the cells and the exterior environment. Donnan potential is a membrane potential across the outer membrane, resulted from the selective permeability of the membrane, which plays a pivotal role in the permeability of many antibiotics. In this review, we discussed factors that affect the intensity of the Donnan potential, including the osmotic strength and pH of the external media, the osmoregulated periplasmic glucans …


Synthesis And Crystal Structures Of 3,6-Di­Hy­Droxy­Picolinic Acid And Its Labile Inter­Mediate Dipotassium 3-Hy­Dr­Oxy-6-(Sulfonato­­Oxy)Pyridine-2-Carboxyl­Ate Monohydrate, Edward J. Behrman, Sean R. Parkin May 2021

Synthesis And Crystal Structures Of 3,6-Di­Hy­Droxy­Picolinic Acid And Its Labile Inter­Mediate Dipotassium 3-Hy­Dr­Oxy-6-(Sulfonato­­Oxy)Pyridine-2-Carboxyl­Ate Monohydrate, Edward J. Behrman, Sean R. Parkin

Chemistry Faculty Publications

A simplified two-step synthesis of 3,6-di­hydroxy­picolinic acid (3-hy­droxy-6-oxo-1,6-di­hydro­pyridine-2-carb­oxy­lic acid), C6H5NO4 (II), an inter­mediate in the metabolism of picolinic acid, is described. The crystal structure of II, along with that of a labile inter­mediate, dipotassium 3-hy­droxy-6-(sulfonato­oxy)pyridine-2-carboxyl­ate monohydrate, 2K+·C6H3NO7S2−·H2O (I), is also described. Compound I comprises a pyridine ring with carboxyl­ate, hydroxyl (connected by an intra­molecular O—H⋯O hydrogen bond), and sulfate groups at the 2-, 3-, and 6-positions, respectively, along with two potassium cations for charge balance and one water …


Suppressing Bias Stress Degradation In High Performance Solution Processed Organic Transistors Operating In Air, Hamna F. Iqbal, Qianxiang Ai, Karl J. Thorley, Hu Chen, Iain Mcculloch, Chad Risko, John E. Anthony, Oana D. Jurchescu Apr 2021

Suppressing Bias Stress Degradation In High Performance Solution Processed Organic Transistors Operating In Air, Hamna F. Iqbal, Qianxiang Ai, Karl J. Thorley, Hu Chen, Iain Mcculloch, Chad Risko, John E. Anthony, Oana D. Jurchescu

Chemistry Faculty Publications

Solution processed organic field effect transistors can become ubiquitous in flexible optoelectronics. While progress in material and device design has been astonishing, low environmental and operational stabilities remain longstanding problems obstructing their immediate deployment in real world applications. Here, we introduce a strategy to identify the most probable and severe degradation pathways in organic transistors and then implement a method to eliminate the main sources of instabilities. Real time monitoring of the energetic distribution and transformation of electronic trap states during device operation, in conjunction with simulations, revealed the nature of traps responsible for performance degradation. With this information, we …


Direct Detection Of 5-Mev Protons By Flexible Organic Thin-Film Devices, Ilaria Fratelli, Andrea Ciavatti, Enrico Zanazzi, Laura Basiricò, Massimo Chiari, Laura Fabbri, John E. Anthony, Alberto Quaranta, Beatrice Fraboni Apr 2021

Direct Detection Of 5-Mev Protons By Flexible Organic Thin-Film Devices, Ilaria Fratelli, Andrea Ciavatti, Enrico Zanazzi, Laura Basiricò, Massimo Chiari, Laura Fabbri, John E. Anthony, Alberto Quaranta, Beatrice Fraboni

Chemistry Faculty Publications

The direct detection of 5-MeV protons by flexible organic detectors based on thin films is here demonstrated. The organic devices act as a solid-state detector, in which the energy released by the protons within the active layer of the sensor is converted into an electrical current. These sensors can quantitatively and reliably measure the dose of protons impinging on the sensor both in real time and in integration mode. This study shows how to detect and exploit the energy absorbed both by the organic semiconducting layer and by the plastic substrate, allowing to extrapolate information on the present and past …


Two-Electron Donating Phenothiazines And Use Thereof, Susan A. Odom, Aman Preet Kaur, Matthew D. Casselman, Nuwan Harsha Attanayake Mar 2021

Two-Electron Donating Phenothiazines And Use Thereof, Susan A. Odom, Aman Preet Kaur, Matthew D. Casselman, Nuwan Harsha Attanayake

Chemistry Faculty Patents

Compounds for use as electrolyte in a non-aqueous redox battery are provided, including an N-substituted phenothiazine compound according to the formula: (see patent for formula.)

R' is alkyl and R is selected from alkyl, aryl, alkylaryl, alkoxyaryl, alkylcarboxyl, arylcarbonyl, haloalkyl, perfluo- roalkyl, glycol, polyether, haloaryl, a negative electrolyte, a polymerizable unit, and a polymer.


Rechargeable Batteries Including High-Voltage Cathode And Redox Shuttle Conferring Overcharge Protection, Susan A. Odom, Aman Preet Kaur, Corrine F. Elliott Jan 2021

Rechargeable Batteries Including High-Voltage Cathode And Redox Shuttle Conferring Overcharge Protection, Susan A. Odom, Aman Preet Kaur, Corrine F. Elliott

Chemistry Faculty Patents

Compounds for use as photoredox catalysts and as redox shuttles in a rechargeable battery having a high-voltage cathode providing overcharge protection capabilities are provided, including a compound according to the formula: (see patent for formula)

wherein R is selected from the group consisting of alkyl, aryl, alkylaryl, alkoxyaryl, alkylcarboxyl, aryl carbonyl, haloalkyl, perfluoroalkyl, glycols, haloaryl, a negative electrolyte, and a polymer.


Modes Of Transmission Of Severe Acute Respiratory Syndrome-Coronavirus-2 (Sars-Cov-2) And Factors Influencing On The Airborne Transmission: A Review, Mahdieh Delikhoon, Marcelo I. Guzman, Ramin Nabizadeh, Abbas Norouzian Baghani Jan 2021

Modes Of Transmission Of Severe Acute Respiratory Syndrome-Coronavirus-2 (Sars-Cov-2) And Factors Influencing On The Airborne Transmission: A Review, Mahdieh Delikhoon, Marcelo I. Guzman, Ramin Nabizadeh, Abbas Norouzian Baghani

Chemistry Faculty Publications

The multiple modes of SARS-CoV-2 transmission including airborne, droplet, contact, and fecal–oral transmissions that cause coronavirus disease 2019 (COVID-19) contribute to a public threat to the lives of people worldwide. Herein, different databases are reviewed to evaluate modes of transmission of SARS-CoV-2 and study the effects of negative pressure ventilation, air conditioning system, and related protection approaches of this virus. Droplet transmission was commonly reported to occur in particles with diameter >5 µm that can quickly settle gravitationally on surfaces (1–2 m). Instead, fine and ultrafine particles (airborne transmission) can stay suspended for an extended period of time (≥2 h) …


Numerical Reconstruction Of Spalled Particle Trajectories In An Arc-Jet Environment, Raghava S. C. Davuluri, Sean C. C. Bailey, Kaveh A. Tagavi, Alexandre Martin Jan 2021

Numerical Reconstruction Of Spalled Particle Trajectories In An Arc-Jet Environment, Raghava S. C. Davuluri, Sean C. C. Bailey, Kaveh A. Tagavi, Alexandre Martin

Mechanical Engineering Faculty Publications

To evaluate the effects of spallation on ablative material, it is necessary to evaluate the mass loss. To do so, a Lagrangian particle trajectory code is used to reconstruct trajectories that match the experimental data for all kinematic parameters. The results from spallation experiments conducted at the NASA HYMETS facility over a wedge sample were used. A data-driven adaptive methodology was used to adapts the ejection parameters until the numerical trajectory matches the experimental data. The preliminary reconstruction results show that the size of the particles seemed to be correlated with the location of the ejection event. The size of …


N-Type Charge Transport In Heavily P-Doped Polymers, Zhiming Liang, Hyun Ho Choi, Xuyi Luo, Tuo Liu, Ashkan Abtahi, Uma Shantini Ramasamy, J. Andrew Hitron, Kyle N. Baustert, Jacob L. Hempel, Alex M. Boehm, Armin Ansary, Douglas R. Strachan, Jianguo Mei, Chad Risko, Vitaly Podzorov, Kenneth R. Graham Jan 2021

N-Type Charge Transport In Heavily P-Doped Polymers, Zhiming Liang, Hyun Ho Choi, Xuyi Luo, Tuo Liu, Ashkan Abtahi, Uma Shantini Ramasamy, J. Andrew Hitron, Kyle N. Baustert, Jacob L. Hempel, Alex M. Boehm, Armin Ansary, Douglas R. Strachan, Jianguo Mei, Chad Risko, Vitaly Podzorov, Kenneth R. Graham

Chemistry Faculty Publications

It is commonly assumed that charge-carrier transport in doped π-conjugated polymers is dominated by one type of charge carrier, either holes or electrons, as determined by the chemistry of the dopant. Here, through Seebeck coefficient and Hall effect measurements, we show that mobile electrons contribute substantially to charge-carrier transport in π-conjugated polymers that are heavily p-doped with strong electron acceptors. Specifically, the Seebeck coefficient of several p-doped polymers changes sign from positive to negative as the concentration of the oxidizing agents FeCl3 or NOBF4 increase, and Hall effect measurements for the same p-doped polymers reveal that …


Review On Carbon Dioxide Utilization For Cycloaddition Of Epoxides By Ionic Liquid-Modified Hybrid Catalysts: Effect Of Influential Parameters And Mechanisms Insight, Jimmy Nelson Appaturi, Rajabathar. Jothi Ramalingam, Muthu Kumaran Gnanamani, Govindasami Periyasami, Prabhakarn Arunachalam, Rohana Adnan, Farook Adam, Mohammed D. Wasmiah, Hamad A. Al‐Lohedan Jan 2021

Review On Carbon Dioxide Utilization For Cycloaddition Of Epoxides By Ionic Liquid-Modified Hybrid Catalysts: Effect Of Influential Parameters And Mechanisms Insight, Jimmy Nelson Appaturi, Rajabathar. Jothi Ramalingam, Muthu Kumaran Gnanamani, Govindasami Periyasami, Prabhakarn Arunachalam, Rohana Adnan, Farook Adam, Mohammed D. Wasmiah, Hamad A. Al‐Lohedan

Center for Applied Energy Research Faculty and Staff Publications

The storage, utilization, and control of the greenhouse (CO2) gas is a topic of interest for researchers in academia and society. The present review article is dedicating to cover the overall role of ionic liquid-modified hybrid materials in cycloaddition reactions. Special emphasis is on the synthesis of various cyclic carbonate using ionic liquid-based modified catalysts. Catalytic activity studies have discussed with respect to process conditions and their effects on conversion and product selectivity for the reaction of cycloaddition of CO2 with styrene oxide. The reaction temperature and the partial pressure of CO2 have found to play …


Dark Iron-Catalyzed Reactions In Acidic And Viscous Aerosol Systems Efficiently Form Secondary Brown Carbon, Hind A. Al-Abadleh, Md Sohel Rana, Wisam Mohammed, Marcelo I. Guzman Dec 2020

Dark Iron-Catalyzed Reactions In Acidic And Viscous Aerosol Systems Efficiently Form Secondary Brown Carbon, Hind A. Al-Abadleh, Md Sohel Rana, Wisam Mohammed, Marcelo I. Guzman

Chemistry Faculty Publications

Iron-driven secondary brown carbon formation reactions from water-soluble organics in cloud droplets and aerosols create insoluble and soluble products of emerging atmospheric importance. This work shows, for the first time, results on dark iron-catalyzed polymerization of catechol forming insoluble black polycatechol particles and colored water-soluble oligomers under conditions characteristic of viscous multicomponent aerosol systems with relatively high ionic strength (I = 1–12 m) and acidic pH (∼2). These systems contain ammonium sulfate (AS)/nitrate (AN) and C3–C5 dicarboxylic acids, namely, malonic, malic, succinic, and glutaric acids. Using dynamic light scattering (DLS) and ultra high pressure liquid chromatography-mass spectrometry (UHPLC-MS), …


An Overview Of The Effect Of Bioaerosol Size In Coronavirus Disease 2019 Transmission, Marcelo I. Guzman Dec 2020

An Overview Of The Effect Of Bioaerosol Size In Coronavirus Disease 2019 Transmission, Marcelo I. Guzman

Chemistry Faculty Publications

The fast spread of coronavirus disease 2019 (COVID-19) constitutes a worldwide challenge to the public health, educational and trade systems, affecting the overall well-being of human societies. The high transmission and mortality rates of this virus, and the unavailability of a vaccine or treatment, resulted in the decision of multiple governments to enact measures of social distancing. Such measures can reduce the exposure to bioaerosols, which can result in pathogen deposition in the respiratory tract of the host causing disease and an immunological response. Thus, it is important to consider the validity of the proposal for keeping a distance of …


Application Of A Small Unmanned Aerial System To Measure Ammonia Emissions From A Pilot Amine-Co2 Capture System, Travis J. Schuyler, Bradley Irvin, Keemia Abad, Jesse G. Thompson, Kunlei Liu, Marcelo I. Guzman Dec 2020

Application Of A Small Unmanned Aerial System To Measure Ammonia Emissions From A Pilot Amine-Co2 Capture System, Travis J. Schuyler, Bradley Irvin, Keemia Abad, Jesse G. Thompson, Kunlei Liu, Marcelo I. Guzman

Chemistry Faculty Publications

The quantification of atmospheric gases with small unmanned aerial systems (sUAS) is expanding the ability to safely perform environmental monitoring tasks and quickly evaluate the impact of technologies. In this work, a calibrated sUAS is used to quantify the emissions of ammonia (NH3) gas from the exit stack a 0.1 MWth pilot-scale carbon capture system (CCS) employing a 5 M monoethanolamine (MEA) solvent to scrub CO2 from coal combustion flue gas. A comparison of the results using the sUAS against the ion chromatography technique with the EPA CTM-027 method for the standard emission sampling of NH3 …


Synthesis, Characterization, And Antiproliferative Activity Of Novel Chiral [Quinoxp*Aucl2]+ Complexes, Adedamola S. Arojojoye, R. Tyler Mertens, Samuel Ofori, Sean R. Parkin, Samuel G. Awuah Dec 2020

Synthesis, Characterization, And Antiproliferative Activity Of Novel Chiral [Quinoxp*Aucl2]+ Complexes, Adedamola S. Arojojoye, R. Tyler Mertens, Samuel Ofori, Sean R. Parkin, Samuel G. Awuah

Chemistry Faculty Publications

Herein is reported the synthesis of two Au(III) complexes bearing the (R,R)-(–)-2,3-Bis(tert-butylmethylphosphino)quinoxaline (R,R-QuinoxP*) or (S,S)-(+)-2,3-Bis(tert-butylmethylphosphino)quinoxaline (S,S-QuinoxP*) ligands. By reacting two stoichiometric equivalents of HAuCl4.3H2O to one equivalent of the corresponding QuinoxP* ligand, (R,R)-(–)-2,3-Bis(tert-butylmethylphosphino)quinoxalinedichlorogold(III) tetrachloroaurates(III) (1) and (S,S)-(+)-2,3-Bis(tert-butylmethylphosphino)quinoxalinedichlorogold(III) tetrachloroaurates(III) (2) were formed, respectively, in moderate yields. The structure of (S,S)-(+)-2,3-Bis(tert-butylmethylphosphino)quinoxalinedichlorogold(III) tetrachloroaurates(III) (2) was further confirmed by X-ray crystallography. The antiproliferative activities of the two compounds were evaluated in a panel of cell lines and exhibited promising results comparable to auranofin and cisplatin with …


1,9,10-Substituted Phenothiazine Derivatives With Strained Radical Cations And Use Thereof, Susan A. Odom, Chad Risko, Matthew D. Casselman, Corrine F. Elliott, Nuwan Harsha Attanayake, Subrahmanyam Modekrutti Dec 2020

1,9,10-Substituted Phenothiazine Derivatives With Strained Radical Cations And Use Thereof, Susan A. Odom, Chad Risko, Matthew D. Casselman, Corrine F. Elliott, Nuwan Harsha Attanayake, Subrahmanyam Modekrutti

Chemistry Faculty Patents

Compounds for use in a rechargeable battery are provided, including a compound according to the formula: (see patent for the formula)

wherein R1 and R9 are independently selected from the group consisting of H, alkyl, aryl, perfluoroaryl, perfluoroalkyl, alkylaryl, alkoxyaryl, alkylcarboxyl, aryl carbonyl, haloalkyl, perfluoroalkyl, glycols, haloaryl, a negative electrolyte, and a polymer, so long as when R1 is H, R9 is not H; and R10 is selected from the group consisting of methyl, alkyl, aryl, alkylaryl, alkoxyaryl, alkylcarboxyl, aryl carbonyl, haloalkyl, perfluoroalkyl, perfluoroaryl, glycols, haloaryl, an oligomer, and a polymer.


Atmospheric Measurements With Unmanned Aerial Systems (Uas), Marcelo I. Guzman Nov 2020

Atmospheric Measurements With Unmanned Aerial Systems (Uas), Marcelo I. Guzman

Chemistry Faculty Publications

This Special Issue provides the first literature collection focused on the development and implementation of unmanned aircraft systems (UAS) and their integration with sensors for atmospheric measurements on Earth. The research covered in the Special Issue combines chemical, physical, and meteorological measurements performed in field campaigns as well as conceptual and laboratory work. Useful examples for the development of platforms and autonomous systems for environmental studies are provided, which demonstrate how careful the operation of sensors aboard UAS must be to gather information for remote sensing in the atmosphere. The work serves as a key collection of articles to introduce …