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Articles 4801 - 4830 of 33144

Full-Text Articles in Chemistry

Mineralogy And Geochemistry Of The Asanje Iron Ore Deposit Within The Mayamaya-Hombolo Belt, Dodoma Region, Central Tanzania, Yusto J. Shine, Michael M. Msabi, Jagarlamudi Seetharamaiah Sep 2022

Mineralogy And Geochemistry Of The Asanje Iron Ore Deposit Within The Mayamaya-Hombolo Belt, Dodoma Region, Central Tanzania, Yusto J. Shine, Michael M. Msabi, Jagarlamudi Seetharamaiah

Tanzania Journal of Science

This paper presents the mineralogy and chemical composition including iron ore impurities to ascertain its suitability for industrial applications. The Asanje iron ore deposit is hosted in Precambrian volcano-sedimentary rocks in the Mayamaya-Hombolo Belt in Dodoma region, within the Lake Nyanza Superterrane. Iron ores are found in two parallel ridges trending NW-SE. Ridge I occurs as vein and banded hematite-type ore and Ridge II as massive-type ore. A total of 24 ore samples were analysed for major and trace elements by XRF and petrographic studies by optical microscopy and XRD. The XRD results revealed that hematite and goethite are the …


Evaluation Of Natural Antifungal Compounds From Artemisia Afra And Its Effectiveness On Prevention Of Aflatoxins, Noela G. Kilenga, Daniel Maeda, Oscar Kibazohi, Lilian D. Kaale Sep 2022

Evaluation Of Natural Antifungal Compounds From Artemisia Afra And Its Effectiveness On Prevention Of Aflatoxins, Noela G. Kilenga, Daniel Maeda, Oscar Kibazohi, Lilian D. Kaale

Tanzania Journal of Science

Artemisia afra is a medicinal plant with antimicrobial activities, known to treat tuberculosis, measles, cough, and influenza. In consequence, its applications have increasingly become pivotal to control various microbes which cause different diseases. This study therefore, evaluated the chemical composition and the antifungal activity of A. afra essential oil. The extraction of essential oil was done using steam distillation. The essential oil chemical composition was analysed by GC-MS. The analysis revealed 19 compounds from A. afra. The main compounds were borneol (71.529%), terpinen-4-ol (8.582%), β-thujone (3.283%), β-terpineol (2.590%), α-terpineol (1.791%), chrysanthenone (1.507%), myrtenal (1.393%), eucalyptol (1,8-cineole) (1.263%), cis-sabinene hydrate (1.172%) …


Microstructural Origin Of The High-Energy Storage Performance In Epitaxial Lead-Free Ba(Zr 0.2 Ti 0.8 )O 3 Thick Films, Jun Ouyang, Xianke Wang, Changtao Shao, Hongbo Cheng, Hanfei Zhu, Yuhang Ren Sep 2022

Microstructural Origin Of The High-Energy Storage Performance In Epitaxial Lead-Free Ba(Zr 0.2 Ti 0.8 )O 3 Thick Films, Jun Ouyang, Xianke Wang, Changtao Shao, Hongbo Cheng, Hanfei Zhu, Yuhang Ren

Publications and Research

In our previous work, epitaxial Ba(Zr 0.2 Ti 0.8 )O 3 thick films (~1–2 μ m) showed an excellent energy storage performance with a large recyclable energy density (~58 J/cc) and a high energy efficiency (~92%), which was attributed to a nanoscale entangled heterophase polydomain structure. Here, we propose a detailed analysis of the structure–property relationship in these film materials, using an annealing process to illustrate the effect of nanodomain entanglement on the energy storage performance. It is revealed that an annealing-induced stress relaxation led to the segregation of the nanodomains (via detailed XRD analyses), and a degraded energy storage …


Leveraging The Structure Of Dnaja1 To Discover Novel Potential Pancreatic Cancer Therapies, Heidi E. Roth, Aline De Lima Leite, Nicolas Y. Palermo, Robert Powers Sep 2022

Leveraging The Structure Of Dnaja1 To Discover Novel Potential Pancreatic Cancer Therapies, Heidi E. Roth, Aline De Lima Leite, Nicolas Y. Palermo, Robert Powers

Department of Chemistry: Faculty Publications

Pancreatic cancer remains one of the deadliest forms of cancer with a 5-year survival rate of only 11%. Difficult diagnosis and limited treatment options are the major causes of the poor outcome for pancreatic cancer. The human protein DNAJA1 has been proposed as a potential therapeutic target for pancreatic cancer, but its cellular and biological functions remain unclear. Previous studies have suggested that DNAJA10s cellular activity may be dependent upon its protein binding partners. To further investigate this assertion, the first 107 amino acid structures of DNAJA1 were solved by NMR, which includes the classical J-domain and its associated linker …


Symmetry-Resolved Co Desorption And Oxidation Dynamics On O/Ru(0001) Probed At The C K-Edge By Ultrafast X-Ray Spectroscopy, Jerry Larue, Boyang Liu, Gabriel L. S. Rodrigues, Chang Liu, Jose Antonio Garrido Torres, Simon Schreck, Elias Diesen, Matthew Weston, Hirohito Ogasawara, Fivos Perakis, Martina Dell'angela, Flavio Capotondi, Devon Ball, Conner Carnahan, Gary Zeri, Luca Giannessi, Emanuele Pedersoli, Denys Naumenko, Peter Amann, Ivaylo Nikolov, Lorenzo Raimondi, Carlo Spezzani, Martin Beye, Johannes Voss, Hsin-Yi Wang, Filippo Cavalca, Jörgen Gladh, Sergey Koroidov, Frank Abild-Pedersen, Manuel Kolb, Piter S. Miedema, Roberto Costantini, Tony F. Heinz, Alan C. Luntz, Lars G. M. Pettersson, Anders Nilsson Sep 2022

Symmetry-Resolved Co Desorption And Oxidation Dynamics On O/Ru(0001) Probed At The C K-Edge By Ultrafast X-Ray Spectroscopy, Jerry Larue, Boyang Liu, Gabriel L. S. Rodrigues, Chang Liu, Jose Antonio Garrido Torres, Simon Schreck, Elias Diesen, Matthew Weston, Hirohito Ogasawara, Fivos Perakis, Martina Dell'angela, Flavio Capotondi, Devon Ball, Conner Carnahan, Gary Zeri, Luca Giannessi, Emanuele Pedersoli, Denys Naumenko, Peter Amann, Ivaylo Nikolov, Lorenzo Raimondi, Carlo Spezzani, Martin Beye, Johannes Voss, Hsin-Yi Wang, Filippo Cavalca, Jörgen Gladh, Sergey Koroidov, Frank Abild-Pedersen, Manuel Kolb, Piter S. Miedema, Roberto Costantini, Tony F. Heinz, Alan C. Luntz, Lars G. M. Pettersson, Anders Nilsson

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

We report on carbon monoxide desorption and oxidation induced by 400 nm femtosecond laser excitation on the O/Ru(0001) surface probed by time-resolved x-ray absorption spectroscopy (TR-XAS) at the carbon K-edge. The experiments were performed under constant background pressures of CO (6 × 10−8 Torr) and O2 (3 × 10−8 Torr). Under these conditions, we detect two transient CO species with narrow 2π* peaks, suggesting little 2π* interaction with the surface. Based on polarization measurements, we find that these two species have opposing orientations: (1) CO favoring a more perpendicular orientation and (2) CO favoring a more parallel orientation …


Probing Mechanisms Of Binding And Allostery In The Sars-Cov-2 Spike Omicron Variant Complexes With The Host Receptor: Revealing Functional Roles Of The Binding Hotspots In Mediating Epistatic Effects And Communication With Allosteric Pockets, Gennady M. Verkhivker, Steve Agajanian, Ryan Kassab, Keerthi Krishnan Sep 2022

Probing Mechanisms Of Binding And Allostery In The Sars-Cov-2 Spike Omicron Variant Complexes With The Host Receptor: Revealing Functional Roles Of The Binding Hotspots In Mediating Epistatic Effects And Communication With Allosteric Pockets, Gennady M. Verkhivker, Steve Agajanian, Ryan Kassab, Keerthi Krishnan

Mathematics, Physics, and Computer Science Faculty Articles and Research

In this study, we performed all-atom MD simulations of RBD–ACE2 complexes for BA.1, BA.1.1, BA.2, and BA.3 Omicron subvariants, conducted a systematic mutational scanning of the RBD–ACE2 binding interfaces and analysis of electrostatic effects. The binding free energy computations of the Omicron RBD–ACE2 complexes and comprehensive examination of the electrostatic interactions quantify the driving forces of binding and provide new insights into energetic mechanisms underlying evolutionary differences between Omicron variants. A systematic mutational scanning of the RBD residues determines the protein stability centers and binding energy hotpots in the Omicron RBD–ACE2 complexes. By employing the ensemble-based global network analysis, we …


Preface To Special Issue On Water Electrolysis For Hydrogen Production, Li Li, Jin-Song Hu, Zi-Dong Wei Sep 2022

Preface To Special Issue On Water Electrolysis For Hydrogen Production, Li Li, Jin-Song Hu, Zi-Dong Wei

Journal of Electrochemistry

No abstract provided.


The Rapid Preparation Of Efficient Mofeco-Based Bifunctional Electrocatalysts Via Joule Heating For Overall Water Splitting, Ao Zhou, Wei-Jian Guo, Yue-Qing Wang, Jin-Tao Zhang Sep 2022

The Rapid Preparation Of Efficient Mofeco-Based Bifunctional Electrocatalysts Via Joule Heating For Overall Water Splitting, Ao Zhou, Wei-Jian Guo, Yue-Qing Wang, Jin-Tao Zhang

Journal of Electrochemistry

Water electrolysis is an available way to obtain green hydrogen. The development of highly efficient electrocatalysts is a current research hotspot for water splitting, but it remains challenging. Herein, we demonstrate the synthesis of a robust bifunctional multi-metal electrocatalysts toward water splitting via the rapid Joule-heating conversion of metal precursors. The composition and morphology were well regulated via altering the ratio of metal precursors. In particular, the trimetal MoC/FeO/CoO/carbon cloth (CC) electrode revealed the outstanding bifunctional electrocatalytic performance due to the unique composition and large electrochemical active surface area. Typically, the MoC/FeO/CoO/CC catalyst needed low overpotentials of 121 and 268 …


Self-Supporting Nife Ldhs@Co-Oh-Co3 Nanorod Array Electrode For Alkaline Anion Exchange Membrane Water Electrolyzer, Dan-Dan Guo, Hong-Mei Yu, Jun Chi, Zhi-Gang Shao Sep 2022

Self-Supporting Nife Ldhs@Co-Oh-Co3 Nanorod Array Electrode For Alkaline Anion Exchange Membrane Water Electrolyzer, Dan-Dan Guo, Hong-Mei Yu, Jun Chi, Zhi-Gang Shao

Journal of Electrochemistry

The development of efficient and durable electrodes for anion exchange membrane water electrolyzers (AEMWEs) is essential for hydrogen production. In this work, 2D NiFe layered double hydroxides (NiFe LDHs) nanosheets were grown on the 1D cobaltous carbonate hydroxide nanowires array (Co-OH-CO3) and the unique 3D layered self-supporting nanorod array (NiFe LDHs@Co-OH-CO3/NF) electrode was obtained. Importantly, we demonstrated an efficient and durable self-supporting NiFe LDHs@Co-OH-CO3/NF electrode for oxygen evolution reaction (OER) and as the anode of the AEMWE. In a three-electrode system, the self-supporting NiFe LDHs@Co-OH-CO3/NF electrode showed excellent catalytic activity for OER, …


Surface Structure Engineering Of Feni-Based Pre-Catalyst For Oxygen Evolution Reaction: A Mini Review, Jia-Xin Li, Li-Gang Feng Sep 2022

Surface Structure Engineering Of Feni-Based Pre-Catalyst For Oxygen Evolution Reaction: A Mini Review, Jia-Xin Li, Li-Gang Feng

Journal of Electrochemistry

Nitrite, a widespread raw material, is harmful to human health for long-term consumption. At present, the detection methods of nitrite mainly include chemical analysis, fluorescence, ultraviolet spectrophotometry and chromatography. These methods have ideal sensitivity and selectivity, but also have some characteristics: cumbersome operation, expensive equipment and professional personnel. Therefore, the development of a simple and sensitive nitrite assay is of great significance. In this paper, the Au/rGO/FeOOH composite materials, which revealed good synergistic catalytic performance among the three elements in the composite, were prepared by simple hydrothermal method and reduction method for the first time with large specific surface area …


A Co Porphyrin With Electron-Withdrawing And Hydrophilic Substituents For Improved Electrocatalytic Oxygen Reduction, Hong-Bo Guo, Ya-Ni Wang, Kai Guo, Hai-Tao Lei, Zuo-Zhong Liang, Xue-Peng Zhang, Rui Cao Sep 2022

A Co Porphyrin With Electron-Withdrawing And Hydrophilic Substituents For Improved Electrocatalytic Oxygen Reduction, Hong-Bo Guo, Ya-Ni Wang, Kai Guo, Hai-Tao Lei, Zuo-Zhong Liang, Xue-Peng Zhang, Rui Cao

Journal of Electrochemistry

Understanding factors that influence the catalyst activity for oxygen reduction reaction (ORR) is essential for the rational design of efficient ORR catalysts. Regulating catalyst electronic structure is commonly used to fine-tune electrocatalytic ORR activity. However, modifying the hydrophilicity of catalysts has been rarely reported to improve ORR, which happens at the liquid/gas/solid interface. Herein, we report on two Co porphyrins, namely, NO2-CoP (Co complex of 5,10,15,20-tetrakis(4-nitrophenyl)porphyrin) and 5F-CoP (Co complex of 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin), and their electrocatalytic ORR features. By simultaneously controlling the electronic structure and hydrophilic property of the meso-substituents, the NO2-CoP showed higher electrocatalytic activity than …


Recent Development Of Low Iridium Electrocatalysts Toward Efficient Water Oxidation, Jing Ni, Zhao-Ping Shi, Xian Wang, Yi-Bo Wang, Hong-Xiang Wu, Chang-Peng Liu, Jun-Jie Ge, Wei Xing Sep 2022

Recent Development Of Low Iridium Electrocatalysts Toward Efficient Water Oxidation, Jing Ni, Zhao-Ping Shi, Xian Wang, Yi-Bo Wang, Hong-Xiang Wu, Chang-Peng Liu, Jun-Jie Ge, Wei Xing

Journal of Electrochemistry

Developing high-performance and low-cost electrocatalysts for oxygen evolution reaction (OER) is the key to implementing polymer electrolyte membrane water electrolyzer (PEMWE) for hydrogen production. To date, iridium (Ir) is the state-of-the-art OER catalyst, but still suffers from the insufficient activity and scarce earth abundance, which results in high cost both in stack and electricity. Design low-Ir catalysts with enhanced activity and stability that can match the requirements of high current and long-term operation in PEMWE is thus highly desired, which necessitate a deep understanding of acidic OER mechanisms, unique insights of material design strategies, and reliable performance evaluation norm, especially …


Perovskite-Type Water Oxidation Electrocatalysts, Xiao Liang, Ke-Xin Zhang, Yu-Cheng Shen, Ke Sun, Lei Shi, Hui Chen, Ke-Yan Zheng, Xiao-Xin Zou Sep 2022

Perovskite-Type Water Oxidation Electrocatalysts, Xiao Liang, Ke-Xin Zhang, Yu-Cheng Shen, Ke Sun, Lei Shi, Hui Chen, Ke-Yan Zheng, Xiao-Xin Zou

Journal of Electrochemistry

The development of energy conversion/storage technologies can achieve the reliable and stable renewable energy supply, and bring us a sustainable future. As the core half-reaction of many energy-related systems, water oxidation is the bottleneck due to its sluggish kinetics of the four-concerted proton-electron transfer (CPET) process. This necessitates the exploitation of low cost, highly active and stable water oxidation electrocatalysts. Perovskite-type oxides possess diverse crystal structures, flexible compositions and unique electronic properties, enabling them ideal material platform for the optimization of catalytic performance. In this review, we provide a comprehensive summary for the crystal structures, electronic structures and synthetic methods …


Saturable Absorption Of Free-Electron Laser Radiation By Graphite Near The Carbon K-Edge, Lars Hoffmann, Sasawat Jamnuch, Craig P. Schwartz, Tobias Helk, Sumana L. Raj, Hikaru Mizuno, Riccardo Mincigrucci, Laura Foglia, Emiliano Principi, Shervin Fatehi Sep 2022

Saturable Absorption Of Free-Electron Laser Radiation By Graphite Near The Carbon K-Edge, Lars Hoffmann, Sasawat Jamnuch, Craig P. Schwartz, Tobias Helk, Sumana L. Raj, Hikaru Mizuno, Riccardo Mincigrucci, Laura Foglia, Emiliano Principi, Shervin Fatehi

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

The interaction of intense light with matter gives rise to competing nonlinear responses that can dynamically change material properties. Prominent examples are saturable absorption (SA) and two-photon absorption (TPA), which dynamically increase and decrease the transmission of a sample depending on pulse intensity, respectively. The availability of intense soft X-ray pulses from free-electron lasers (FELs) has led to observations of SA and TPA in separate experiments, leaving open questions about the possible interplay between and relative strength of the two phenomena. Here, we systematically study both phenomena in one experiment by exposing graphite films to soft X-ray FEL pulses of …


Interpretable Machine Learning Models For Molecular Design Of Tyrosine Kinase Inhibitors Using Variational Autoencoders And Perturbation-Based Approach Of Chemical Space Exploration, Keerthi Krishnan, Ryan Kassab, Steve Agajanian, Gennady M. Verkhivker Sep 2022

Interpretable Machine Learning Models For Molecular Design Of Tyrosine Kinase Inhibitors Using Variational Autoencoders And Perturbation-Based Approach Of Chemical Space Exploration, Keerthi Krishnan, Ryan Kassab, Steve Agajanian, Gennady M. Verkhivker

Mathematics, Physics, and Computer Science Faculty Articles and Research

In the current study, we introduce an integrative machine learning strategy for the autonomous molecular design of protein kinase inhibitors using variational autoencoders and a novel cluster-based perturbation approach for exploration of the chemical latent space. The proposed strategy combines autoencoder-based embedding of small molecules with a cluster-based perturbation approach for efficient navigation of the latent space and a feature-based kinase inhibition likelihood classifier that guides optimization of the molecular properties and targeted molecular design. In the proposed generative approach, molecules sharing similar structures tend to cluster in the latent space, and interpolating between two molecules in the latent space …


Wastewater-Informed Public Health Intervention Playbook Sep 2022

Wastewater-Informed Public Health Intervention Playbook

Sustain Magazine

As the SARS-CoV-2 pandemic quickly spread from country to country and continent to continent in 2020, governments and scientists needed a way to track COVID-19 through populations in order to position public health interventions in the most impactful locations. Having a decision-based risk framework may help to guide policy creation that could minimize or prevent possible outbreaks and surges of infection within communities. The University of Louisville in partnership with Louisville’s Department of Public Health and Wellness tested this strategy in 2021 and 2022. This Wastewater-Informed Public Health Intervention Playbook describes the decisions and actions of that academic and public …


Electrospun Poly(3-Hydroxybutyrate-Co-3-Hydroxyvalerate)/Olive Leaf Extract Fiber Mesh As Prospective Bio-Based Scaffold For Wound Healing, Jose Gustavo De La Ossa, Serena Danti, Jasmine Esposito Salsano, Bahareh Azimi, Veronika Tempesti, Niccoletta Barbani, Maria Digiacomo, Marco Macchia, Mohammed Jasim Uddin, Caterina Cristallini Sep 2022

Electrospun Poly(3-Hydroxybutyrate-Co-3-Hydroxyvalerate)/Olive Leaf Extract Fiber Mesh As Prospective Bio-Based Scaffold For Wound Healing, Jose Gustavo De La Ossa, Serena Danti, Jasmine Esposito Salsano, Bahareh Azimi, Veronika Tempesti, Niccoletta Barbani, Maria Digiacomo, Marco Macchia, Mohammed Jasim Uddin, Caterina Cristallini

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Polyhydroxyalkanoates (PHAs) are a family of biopolyesters synthesized by various microorganisms. Due to their biocompatibility and biodegradation, PHAs have been proposed for biomedical applications, including tissue engineering scaffolds. Olive leaf extract (OLE) can be obtained from agri-food biowaste and is a source of polyphenols with remarkable antioxidant properties. This study aimed at incorporating OLE inside poly(hydroxybutyrate-co-hydroxyvalerate) (PHBHV) fibers via electrospinning to obtain bioactive bio-based blends that are useful in wound healing. PHBHV/OLE electrospun fibers with a size of 1.29 ± 0.34 µm were obtained. Fourier transform infrared chemical analysis showed a uniform surface distribution of hydrophilic -OH groups, confirming the …


Reactivity Of Aminophenols In Forming Nitrogen-Containing Brown Carbon From Iron-Catalyzed Reactions, Hind A. Al-Abadleh, Fatemeh Motaghedi, Wisam Mohammed, Md Sohel Rana, Kotiba A. Malek, Dewansh Rastogi, Akua A. Asa-Awuku, Marcelo I. Guzman Sep 2022

Reactivity Of Aminophenols In Forming Nitrogen-Containing Brown Carbon From Iron-Catalyzed Reactions, Hind A. Al-Abadleh, Fatemeh Motaghedi, Wisam Mohammed, Md Sohel Rana, Kotiba A. Malek, Dewansh Rastogi, Akua A. Asa-Awuku, Marcelo I. Guzman

Chemistry Faculty Publications

Nitrogen-containing organic carbon (NOC) in atmospheric particles is an important class of brown carbon (BrC). Redox active NOC like aminophenols received little attention in their ability to form BrC. Here we show that iron can catalyze dark oxidative oligomerization of o- and p-aminophenols under simulated aerosol and cloud conditions (pH 1–7, and ionic strength 0.01–1 M). Homogeneous aqueous phase reactions were conducted using soluble Fe(III), where particle growth/agglomeration were monitored using dynamic light scattering. Mass yield experiments of insoluble soot-like dark brown to black particles were as high as 40%. Hygroscopicity growth factors (κ) of these …


Ligand-Based Virtual Screening And Molecular Docking Of Benzimidazoles As Potential Inhibitors Of Triosephosphate Isomerase Identified New Trypanocidal Agents, Lenci K. Vazquez-Jimenez, Alfredo Juarez-Saldivar, Rogelio Gomez-Escobedo, Timoteo Delgado-Maldonado, Domingo Mendez-Alvarez, Isidro Palos, Debasish Bandyopadhyay, Carlos Gaona-Lopez, Eyra Ortiz-Perez, Benjamin Nogueda-Torres, Esther Ramirez-Moreno, Gildardo Rivera Sep 2022

Ligand-Based Virtual Screening And Molecular Docking Of Benzimidazoles As Potential Inhibitors Of Triosephosphate Isomerase Identified New Trypanocidal Agents, Lenci K. Vazquez-Jimenez, Alfredo Juarez-Saldivar, Rogelio Gomez-Escobedo, Timoteo Delgado-Maldonado, Domingo Mendez-Alvarez, Isidro Palos, Debasish Bandyopadhyay, Carlos Gaona-Lopez, Eyra Ortiz-Perez, Benjamin Nogueda-Torres, Esther Ramirez-Moreno, Gildardo Rivera

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Trypanosoma cruzi (T. cruzi) is a parasite that affects humans and other mammals. T. cruzi depends on glycolysis as a source of adenosine triphosphate (ATP) supply, and triosephosphate isomerase (TIM) plays a key role in this metabolic pathway. This enzyme is an attractive target for the design of new trypanocidal drugs. In this study, a ligand-based virtual screening (LBVS) from the ZINC15 database using benzimidazole as a scaffold was accomplished. Later, a molecular docking on the interface of T. cruzi TIM (TcTIM) was performed and the compounds were grouped by interaction profiles. Subsequently, a selection of compounds was made based …


Understanding The Effect Of Sodium Polyphosphate On Improving The Chemical Stability Of Ti3c2tz Mxene In Water, Shuohan Huang, Varun Natu, Jingyi Tao, Yumin Xia, Vadym Mochalin, Michel W. Barsoum Sep 2022

Understanding The Effect Of Sodium Polyphosphate On Improving The Chemical Stability Of Ti3c2tz Mxene In Water, Shuohan Huang, Varun Natu, Jingyi Tao, Yumin Xia, Vadym Mochalin, Michel W. Barsoum

Chemistry Faculty Research & Creative Works

Degradation of MXenes in aqueous environments severely limits the application and industrialization of this large family of two-dimensional (2D) materials. Hydrolysis and oxidation are now considered as two main degradation mechanisms and while significant efforts have been directed to prolonging the shelf-life of MXenes, separating and studying their degradation mechanisms have lagged behind. Herein, gas analysis via gas chromatography and Raman spectroscopy were used to investigate the effect of sodium polyphosphate, PP, on the degradation of Ti3C2Tz MXene. Transmission and scanning electron microscopies, as well as X-ray photoelectron spectroscopywere also used as complimentary techniques to …


Laboratory Evaluation Of A Novel Self-Healable Polymer Gel For Co2 Leakage Remediation During Co2 Storage And Co2 Flooding, Tao Song, Zhanmiao Zhai, Junchen Liu, Yugandhara Eriyagama, Mohamed Ahdaya, Adel Alotibi, Ze Wang, Thomas P. Schuman, Baojun Bai Sep 2022

Laboratory Evaluation Of A Novel Self-Healable Polymer Gel For Co2 Leakage Remediation During Co2 Storage And Co2 Flooding, Tao Song, Zhanmiao Zhai, Junchen Liu, Yugandhara Eriyagama, Mohamed Ahdaya, Adel Alotibi, Ze Wang, Thomas P. Schuman, Baojun Bai

Chemistry Faculty Research & Creative Works

For CO2 storage in subsurface reservoirs, one of the most crucial requirements is the ability to remediate the leakage caused by the natural fractures or newly generated fractures due to the increasing pore pressure associated with CO2 injection. For CO2 Enhanced Oil Recovery (EOR), high conductivity features such as fractures and void space conduits can severely restrict the CO2 sweep efficiency. Polymer gels have been developed to plug the leakage and improve the sweep efficiency. This work evaluated a CO2 resistant branched self-healable preformed particle gel (CO2-BRPPG) for CO2 plugging purpose. This …


Combining Freestanding Ferroelectric Perovskite Oxides With Two-Dimensional Semiconductors For High Performance Transistors, Sergio Puebla, Thomas Pucher, Victor Rouco, Gabriel Sanchez-Santolino, Yong Xie, Victor Zamora, Fabian A. Cuellar, Federico J. Mompean, Carlos Leon, Carlos O. Island, Mar Garcia-Hernandez, Jacobo Santamaria, Carmen Munuera, Andres Castellanos-Gomez Sep 2022

Combining Freestanding Ferroelectric Perovskite Oxides With Two-Dimensional Semiconductors For High Performance Transistors, Sergio Puebla, Thomas Pucher, Victor Rouco, Gabriel Sanchez-Santolino, Yong Xie, Victor Zamora, Fabian A. Cuellar, Federico J. Mompean, Carlos Leon, Carlos O. Island, Mar Garcia-Hernandez, Jacobo Santamaria, Carmen Munuera, Andres Castellanos-Gomez

Physics & Astronomy Faculty Research

We demonstrate the fabrication of field-effect transistors based on single-layer MoS2 and a thin layer of BaTiO3 (BTO) dielectric, isolated from its parent epitaxial template substrate. Thin BTO provides an ultrahigh-κ gate dielectric effectively screening Coulomb scattering centers. These devices show mobilities substantially larger than those obtained with standard SiO2 dielectrics and comparable with values obtained with hexagonal boron nitride, a dielectric employed for fabrication of high-performance two-dimensional (2D) based devices. Moreover, the ferroelectric character of BTO induces a robust hysteresis of the current vs gate voltage characteristics, attributed to its polarization switching. This hysteresis is strongly suppressed when the …


A Blind Benchmark Of Analysis Tools To Infer Kinetic Rate Constants From Single-Molecule Fret Trajectories, Dorothy A. Erie, Lydia Kisley, Dushani Dunukara Sep 2022

A Blind Benchmark Of Analysis Tools To Infer Kinetic Rate Constants From Single-Molecule Fret Trajectories, Dorothy A. Erie, Lydia Kisley, Dushani Dunukara

Faculty Scholarship

Single-molecule FRET (smFRET) is a versatile technique to study the dynamics and function of biomolecules since it makes nanoscale movements detectable as fluorescence signals. The powerful ability to infer quantitative kinetic information from smFRET data is, however, complicated by experimental limitations. Diverse analysis tools have been developed to overcome these hurdles but a systematic comparison is lacking. Here, we report the results of a blind benchmark study assessing eleven analysis tools used to infer kinetic rate constants from smFRET trajectories. We test them against simulated and experimental data containing the most prominent difficulties encountered in analyzing smFRET experiments: different noise …


Ice-Nucleating Agents In Sea Spray Aerosol Identified And Quantified With A Holistic Multimodal Freezing Model, Peter A. Alpert, Wendy P. Kilthau, Rachel E. O'Brien, Ryan C. Moffet, Mary K. Gilles, Bingbing Wang, Alexander Laskin, Josephine Y. Aller, Daniel A. Knopf Sep 2022

Ice-Nucleating Agents In Sea Spray Aerosol Identified And Quantified With A Holistic Multimodal Freezing Model, Peter A. Alpert, Wendy P. Kilthau, Rachel E. O'Brien, Ryan C. Moffet, Mary K. Gilles, Bingbing Wang, Alexander Laskin, Josephine Y. Aller, Daniel A. Knopf

Pacific Faculty Work

Sea spray aerosol (SSA) is a widely recognized important source of ice-nucleating particles (INPs) in the atmosphere. However, composition-specific identification, nucleation processes, and ice nucleation rates of SSA-INPs have not been well constrained. Microspectroscopic characterization of ambient and laboratory-generated SSA confirms that water-borne exudates from planktonic microorganisms composed of a mixture of proteinaceous and polysaccharidic compounds act as ice-nucleating agents (INAs). These data and data from previously published mesocosm and wave channel studies are subsequently used to further develop the stochastic freezing model (SFM) producing ice nucleation rate coefficients for SSA-INPs. The SFM simultaneously predicts immersion freezing and deposition and …


Markovnikov Alcohols Via Epoxide Hydroboration By Molecular Alkali Metal Catalysts, Guoqi Zhang, Haisu Zeng, Shengping Zheng, Michelle C. Neary, Los Alamos National Laboratory Sep 2022

Markovnikov Alcohols Via Epoxide Hydroboration By Molecular Alkali Metal Catalysts, Guoqi Zhang, Haisu Zeng, Shengping Zheng, Michelle C. Neary, Los Alamos National Laboratory

Publications and Research

Summary

Synthesis of branched “Markovnikov” alcohols is crucial to various chemical industries. The catalytic reduction of substituted epoxides under mild conditions is a highly attractive method for preparing such alcohols. Classical methods based on heterogeneous or homogeneous transition metal-catalyzed hydrogenation, hydroboration, or hydrosilylation usually suffer from poor selectivity, reverse regioselectivity, limited functional group compatibility, high cost, and/or low availability of the catalysts. Here we report the discovery of highly regioselective hydroboration of nonsymmetrical epoxides catalyzed by ligated archetypal reductants in organic chemistry ‒ alkali metal triethylborohydrides. The chemoselectivity and turnover efficiencies of the present catalytic approach are excellent. Thus, terminal …


Chemical Investigation And Drug Discovery Potential Of Terpenoid Secondary Metabolites From Three Deep-Sea Irish Soft Corals, Joshua Thomas Welsch Sep 2022

Chemical Investigation And Drug Discovery Potential Of Terpenoid Secondary Metabolites From Three Deep-Sea Irish Soft Corals, Joshua Thomas Welsch

USF Tampa Graduate Theses and Dissertations

Secondary metabolites produced primarily by terrestrial plants and animals have provided the basis for treatments and cures of human diseases as far back as historians have been able to probe. However, recent technological advances including the self-contained underwater breathing apparatus, and even further remotely operated vehicles, have allowed researchers a unique opportunity for targeted collection of marine organisms at depths previously thought to possess conditions unsustainable for life as was understood. This has afforded a glimpse into the potential for not only life, but the potential for new biochemical adaptations developed over billions of years that have been evolutionarily developed …


In Silico Evaluation Of The Antimalarial Potential Of The Phytoconstituents Of The Azadirachta Indica Plant, Areh E.T., Atolani O., Kambizi L Sep 2022

In Silico Evaluation Of The Antimalarial Potential Of The Phytoconstituents Of The Azadirachta Indica Plant, Areh E.T., Atolani O., Kambizi L

Al-Bahir

Background and Objectives: Malaria, a parasitic protozoan disease caused primarily by Plasmodium falciparum, has killed millions of people in Africa, particularly those with meager or no access to orthodox medical facilities and therapies. Extracts from the Azadirachta indica (neem) plant is believed to possess antimalaria properties among the locals that rely on herbs. Numerous in - vivo studies have suggested the antimalarial properties of neem extract and phytochemicals. This study employs an in - silico method through molecular docking techniques to provide insight while adding credence to the antimalarial potential of phytochemicals of neem plants as claimed …


Ambient-Pressure Ozone Treatment Enables Tuning Of Oxygen Vacancy Concentration In The La1−XSrXFeo3−Δ (0 ≤ X ≤ 1) Perovskite Oxides, Geletu Qing, David Thompson, Mourad Benamara, Clemens Heske, Lauren Greenlee, Jingyi Chen Sep 2022

Ambient-Pressure Ozone Treatment Enables Tuning Of Oxygen Vacancy Concentration In The La1−XSrXFeo3−Δ (0 ≤ X ≤ 1) Perovskite Oxides, Geletu Qing, David Thompson, Mourad Benamara, Clemens Heske, Lauren Greenlee, Jingyi Chen

Chemistry and Biochemistry Faculty Research

Oxygen vacancies in metal oxides can determine their properties. However, it is difficult to reduce the oxygen vacancy concentration in metal oxides without annealing them under high pressure. In this work, we develop a facile approach to control oxygen vacancy content via an ozone treatment under ambient pressure during cooling. This approach is demonstrated for the synthesis of La1−xSrxFeO3−δ (0 ≤ x ≤ 1, 0 ≤ δ ≤ 0.5x) perovskite oxides – an important class of energy-related materials due to their wide range of non-stoichiometry, mixed ionic and electronic conductivity, and …


Design Of Pd–Zn Bimetal Mof Nanosheets And Mof-Derived Pd3.9zn6.1/Cns Catalyst For Selective Hydrogenation Of Acetylene Under Simulated Front-End Conditions, Xinxiang Cao, Ruijian Tong, Siye Tang, Ben W.-L. Jang Sep 2022

Design Of Pd–Zn Bimetal Mof Nanosheets And Mof-Derived Pd3.9zn6.1/Cns Catalyst For Selective Hydrogenation Of Acetylene Under Simulated Front-End Conditions, Xinxiang Cao, Ruijian Tong, Siye Tang, Ben W.-L. Jang

Faculty Publications

Novel zinc–palladium–porphyrin bimetal metal–organic framework (MOF) nanosheets were directly synthesized by coordination chelation between Zn(II) and Pd(II) tetra(4-carboxyphenyl) porphin (TCPP(Pd)) using a solvothermal method. Furthermore, a serial of carbon nanosheets supported Pd–Zn intermetallics (Pd–Zn-ins/CNS) with different Pd: Zn atomic ratios were obtained by one-step carbonization under different temperature using the prepared Zn-TCPP(Pd) MOF nanosheets as precursor. In the carbonization process, Pd–Zn-ins went through the transformation from PdZn (650 C) to Pd3.9Zn6.1 (~950 C) then to Pd3.9Zn6.1/Pd (1000 C) with the temperature increasing. The synthesized Pd–Zn-ins/CNS were further employed as catalysts for selective hydrogenation of acetylene. Pd3.9Zn6.1 showed the best catalytic …


Direct Ink 3d Printing Of Porous Carbon Monoliths For Gas Separations, Marisa L. Comroe, Kurt W. Kolasinski, Dipendu Saha Sep 2022

Direct Ink 3d Printing Of Porous Carbon Monoliths For Gas Separations, Marisa L. Comroe, Kurt W. Kolasinski, Dipendu Saha

Chemistry Faculty Publications

Additive manufacturing or 3D printing is the advanced method of manufacturing monolithic adsorbent materials. Unlike beads or pellets, 3D monolithic adsorbents possess the advantages of widespread structural varieties, low heat and mass transfer resistance, and low channeling of fluids. Despite a large volume of research on 3D printing of adsorbents having been reported, such studies on porous carbons are highly limited. In this work, we have reported direct ink 3D printing of porous carbon; the ink consisted of commercial activated carbon, a gel of poly(4-vinylphenol) and Pluronic F127 as plasticizer, and bentonite as the binder. The 3D printing was performed …