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Articles 181 - 210 of 12036

Full-Text Articles in Chemistry

Speciation Of Elements Via A Sequential Extraction Procedure In Municipal Wastewater Biosolids From Three Rural Wwtp In East Texas (Usa), Kefa K. Onchoke Aug 2023

Speciation Of Elements Via A Sequential Extraction Procedure In Municipal Wastewater Biosolids From Three Rural Wwtp In East Texas (Usa), Kefa K. Onchoke

Faculty Publications

In this data article, the bioavailability of elements in municipal wastewater sludge (also known as biosolids) in samples collected from three treatment plants in East Texas, USA was evaluated. Although detailed speciation of the metals were assessed by using inductively coupled plasma optical spectroscopy (ICP-OES), and were discussed in the research article titled “Evaluating bioavailability of elements in municipal wastewater sludge (Biosolids) from three rural wastewater treatment plants in East Texas (USA) by a sequential extraction procedure” [1], this report presents the absolute raw concentrations and fractionations of the 26 metals from the biosolids (Nacogdoches Wastewater Sludge, Lufkin Wastewater Sludge, …

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Utilizing Low-Cost Sensors To Monitor Indoor Air Quality In Mongolian Gers, Callum Flowerday, Jaron C. Hansen, Phil Lundrigan, Christopher Kitras Aug 2023

Utilizing Low-Cost Sensors To Monitor Indoor Air Quality In Mongolian Gers, Callum Flowerday, Jaron C. Hansen, Phil Lundrigan, Christopher Kitras

Faculty Publications

Air quality has important climate and health effects. There is a need, therefore, to monitor air quality both indoors and outdoors. Methods of measuring air quality should be cost-effective if they are to be used widely, and one such method is low-cost sensors (LCS). This study reports on the use of LCSs in Ulaanbataar, Mongolia to measure PM2.5 concentrations inside yurts or “gers”. Some of these gers were part of a non-government agency (NGO) initiative to improve insulating properties of these housing structures. The goal of the NGO was to decrease particulate emissions inside the gers; a secondary result …

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Synthesis Of 2-Arylpyridines By The Suzuki–Miyaura Cross-Coupling Of Pyfluor With Hetero (Aryl) Boronic Acids And Esters, Juan Rueda-Espinosa, Dewni Ramanayake, Nicholas Ball, Jennifer A. Love Aug 2023

Synthesis Of 2-Arylpyridines By The Suzuki–Miyaura Cross-Coupling Of Pyfluor With Hetero (Aryl) Boronic Acids And Esters, Juan Rueda-Espinosa, Dewni Ramanayake, Nicholas Ball, Jennifer A. Love

Pomona Faculty Publications and Research

The Suzuki–Miyaura cross-coupling of pyridine-2-sulfonyl fluoride (PyFluor) with hetero(aryl) boronic acids and pinacol boronic esters is reported. The reactions can be performed using Pd(dppf)Cl2 as the catalyst, at temperatures between 65 and 100 °C and in the presence of water and oxygen. This transformation generates 2-arylpyridines in modest to good yields (5%–89%).

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Μ-1,6-Dioxo-1,6-Diphenylhexane-3,4-Diolato-Bis[(2,2′-Bipyridine)Chloridocopper(Ii)] Dihydrate A; B; A, Luke Nye, Shane G. Tefler, Mark M. Turnbull Aug 2023

Μ-1,6-Dioxo-1,6-Diphenylhexane-3,4-Diolato-Bis[(2,2′-Bipyridine)Chloridocopper(Ii)] Dihydrate A; B; A, Luke Nye, Shane G. Tefler, Mark M. Turnbull

Chemistry

The reaction of CuCl2 with 1,6-diphenyl-1,3,5,6-hexanetetrone and 2,2′-bipyridine (bipy) in ethanol gave crystals of the corresponding bimetallic complex, [Cu2(C18H12O4)Cl2(C10H8N2)2]·2H2O. The molecule is centrosymmetric with each CuII ion coordinated to two oxygen atoms from the tetronediate, two nitrogen atoms from a bipy ligand and one coordinated chloride ion. A water molecule of crystallization forms hydrogen bonds to the chloride ions, linking the molecules into a chain parallel to the bc-face diagonal. © 2023 The Author(s).

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Broadband Cavity-Enhanced Absorption Spectroscopy (Bbceas) Coupled With An Interferometer For On-Band And Off-Band Detection Of Glyoxal, Callum Flowerday, Jaron Hansen, Ryan Thalman Aug 2023

Broadband Cavity-Enhanced Absorption Spectroscopy (Bbceas) Coupled With An Interferometer For On-Band And Off-Band Detection Of Glyoxal, Callum Flowerday, Jaron Hansen, Ryan Thalman

ScholarsArchive Data

These data are the raw data from the BBCEAS. The "data_" files are the PMT data and the "DualDetection_08_02_2023" files are the spectrograph data. The PMT data are found in column 7 of the sheet. Column 1 is the time stamp.

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Introducing High School Biology Students To Biochemistry With A Short, Content-Oriented Module, Archer Harrold, Allison Cruikshank, Bryan Penas, Rebecca Roston Aug 2023

Introducing High School Biology Students To Biochemistry With A Short, Content-Oriented Module, Archer Harrold, Allison Cruikshank, Bryan Penas, Rebecca Roston

Chemistry Department: Faculty Publications

Many STEM disciplines are underrepresented to High School students. This is problematic as many students' decisions for college are shaped by their experiences and achievements in high school. Short content-oriented modules have been shown to encourage science identity and otherwise benefit the students' learning. Following the ASBMB's outreach protocol, we developed a short content-oriented module aimed at a high school biology classroom. Students interacted with 3D models of DNA and transcription factors while exploring structure–function relationships and introductory biochemistry topics. The high school teacher was impressed with the students' response to the module, specifically the ease with which students learned, …

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Additive Effects Of Cyclic Peptide [R4w4] When Added Alongside Azithromycin And Rifampicin Against Mycobacterium Avium Infection, Melissa Kelley, Kayvan Sasaninia, Arbi Abnousian, Ali Badaoui, James Owens, Abrianna Beever, Nala Kachour, Rakesh Kumar Tiwari, Vishwanath Venketaraman Aug 2023

Additive Effects Of Cyclic Peptide [R4w4] When Added Alongside Azithromycin And Rifampicin Against Mycobacterium Avium Infection, Melissa Kelley, Kayvan Sasaninia, Arbi Abnousian, Ali Badaoui, James Owens, Abrianna Beever, Nala Kachour, Rakesh Kumar Tiwari, Vishwanath Venketaraman

Pharmacy Faculty Articles and Research

Mycobacterium avium (M. avium), a type of nontuberculous mycobacteria (NTM), poses a risk for pulmonary infections and disseminated infections in immunocompromised individuals. Conventional treatment consists of a 12-month regimen of the first-line antibiotics rifampicin and azithromycin. However, the treatment duration and low antibiotic tolerability present challenges in the treatment of M. avium infection. Furthermore, the emergence of multidrug-resistant mycobacterium strains prompts a need for novel treatments against M. avium infection. This study aims to test the efficacy of a novel antimicrobial peptide, cyclic [R4W4], alongside the first-line antibiotics azithromycin and rifampicin in reducing M. avium survival. Colony-forming unit (CFU) …

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Rural Science Teachers Social Network Analysis Matrices, Rebecca L. Sansom, Tracy Poulsen Aug 2023

Rural Science Teachers Social Network Analysis Matrices, Rebecca L. Sansom, Tracy Poulsen

ScholarsArchive Data

These are the social network matrices for our study of rural science teachers. Each matrix is located on a separate tab on the spreadsheet.

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Changes In An Enzyme Ensemble During Catalysis Observed By High Resolution Xfel Crystallography, Nathan J. Smith, Medhanjali Dasgupta, David C. Wych, Cole Dolamore, Raymond G. Sierra, Stella Lisova, Darya Marchany-Rivera, Aina E. Cohen, Sébastien Boutet, Mark S. Hunter, Christopher Kupitz, Frédéric Poitevin, Frank R. Moss Iii, Aaron S. Brewster, Nicholas K. Sauter, Iris D. Young, Alexander M. Wolff, Virendra K. Tiwari, Nivesh Kumar, David B. Berkowitz, Ryan G. Hadt, Michael C. Thompson, Alec H. Follmer, Mark A. Wilson Aug 2023

Changes In An Enzyme Ensemble During Catalysis Observed By High Resolution Xfel Crystallography, Nathan J. Smith, Medhanjali Dasgupta, David C. Wych, Cole Dolamore, Raymond G. Sierra, Stella Lisova, Darya Marchany-Rivera, Aina E. Cohen, Sébastien Boutet, Mark S. Hunter, Christopher Kupitz, Frédéric Poitevin, Frank R. Moss Iii, Aaron S. Brewster, Nicholas K. Sauter, Iris D. Young, Alexander M. Wolff, Virendra K. Tiwari, Nivesh Kumar, David B. Berkowitz, Ryan G. Hadt, Michael C. Thompson, Alec H. Follmer, Mark A. Wilson

Chemistry Department: Faculty Publications

Enzymes populate ensembles of structures with intrinsically different catalytic proficiencies that are difficult to experimentally characterize. We use time-resolved mix-and-inject serial crystallography (MISC) at an X-ray free electron laser (XFEL) to observe catalysis in a designed mutant (G150T) isocyanide hydratase (ICH) enzyme that enhances sampling of important minor conformations. The active site exists in a mixture of conformations and formation of the thioimidate catalytic intermediate selects for catalytically competent substates. A prior proposal for active site cysteine charge-coupled conformational changes in ICH is validated by determining structures of the enzyme over a range of pH values. A combination of large …

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On The Boundary Of The Cosmos, Daniel Linford Aug 2023

On The Boundary Of The Cosmos, Daniel Linford

Chemistry Department: Faculty Publications

Intuitively, the totality of physical reality – the Cosmos – has a beginning only if (i) all parts of the Cosmos agree on the direction of time (the Direction Condition) and (ii) there is a boundary to the past of all non-initial spacetime points such that there are no spacetime points to the past of the boundary (the Boundary Condition). Following a distinction previously introduced by J. Brian Pitts, the Boundary Condition can be conceived of in two distinct ways: either topologically, i.e., in terms of a closed boundary, or metrically, i.e., in terms of the Cosmos having a finite …

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Crystal Environment Induced Symmetry Reduction (Ceisr): Deep Analysis Of Para-Chloroacetophenone Azine And Generalization, Harmeet Bhoday, Kaidi Yang, Steven P. Kelley, Rainer Glaser Aug 2023

Crystal Environment Induced Symmetry Reduction (Ceisr): Deep Analysis Of Para-Chloroacetophenone Azine And Generalization, Harmeet Bhoday, Kaidi Yang, Steven P. Kelley, Rainer Glaser

Chemistry Faculty Research & Creative Works

The morphologies of sixteen crystal structures of ten symmetrical Xpara-Ph-(Me)C 00000000 00000000 00000000 00000000 11111111 = N-N = C (Me)-Ph-Xpara azines: 1 (Cl), 2 (Br), 3 (I), 4 (OH), 5 (PhO), 6 (CF3), 7 (F), 8 (Me), 9 (NO2), and 10 (PrO) are described. All the azines crystallize forming idioteloamphiphile monolayers (IAMs) and their morphologies fall into the two main classes of "flat" and "shiplap" depending on the lateral offsets between next neighbors in the monolayer. Ab initio studies show that the (E,E)-configured p-disubstituted acetophenone azines are C2-symmetric in the gas phase and that the azine and phenyl twists are …

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A Critical Inter-Subunit Interaction For The Transmission Of The Allosteric Signal In The Agrobacterium Tumefaciens Adp-Glucose Pyrophosphorylase, Hiral Patel, Gabriela Martinez-Ramirez Ms., Emily Dobrzynski, Alberto A. Iglesias, Dali Liu, Miguel Ballicora Aug 2023

A Critical Inter-Subunit Interaction For The Transmission Of The Allosteric Signal In The Agrobacterium Tumefaciens Adp-Glucose Pyrophosphorylase, Hiral Patel, Gabriela Martinez-Ramirez Ms., Emily Dobrzynski, Alberto A. Iglesias, Dali Liu, Miguel Ballicora

Chemistry: Faculty Publications and Other Works

ADP-glucose pyrophosphorylase is a key regulatory enzyme involved in starch and glycogen synthesis in plants and bacteria, respectively. It has been hypothesized that inter-subunit communications are important for the allosteric effect in this enzyme. However, no specific interactions have been identified as part of the regulatory signal. The enzyme from Agrobacterium tumefaciens is a homotetramer allosterically regulated by fructose 6-phosphate and pyruvate. Three pairs of distinct subunit-subunit interfaces are present. Here we focus on an interface that features two symmetrical interactions between Arg11 and Asp141 from one subunit with residues Asp141 and Arg11 of the neighbor subunit, respectively. Previously, scanning …

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Design Of Stormwater Bmps For Surface And Groundwater Protection Based On Site-Scale Soil Properties: Phase I, Kelly Kibler, Lisa Chambers, Melanie Beazley Aug 2023

Design Of Stormwater Bmps For Surface And Groundwater Protection Based On Site-Scale Soil Properties: Phase I, Kelly Kibler, Lisa Chambers, Melanie Beazley

Florida DOT

Much of Earth’s nutrient cycling takes place in soils. Characteristics of soils control physical, chemical, and biological processes that determine rates of nutrient fluxes, storage, or transformation. As remediation of excess nutrients in stormwater runoff is one function of stormwater Best Management Practices (BMPs), the soil profile constitutes one of the most important factors of BMP design. Variation observed in BMP effectiveness (e.g., why one BMP design works effectively in one place and not another) can often be explained by variations in the soil profile, either through direct means or by a soil’s influence on hydraulics of stormwater flow through …

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Research Instrumentation Center (Ric), Ryan Hilger, Purdue University Office Of Research Aug 2023

Research Instrumentation Center (Ric), Ryan Hilger, Purdue University Office Of Research

University Research Core Facility Boilerplate Descriptions

No abstract provided.

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Outgassing Behavior And Heat Treatment Optimization Of Jsc-1a Lunar Regolith Simulant, Ryan P. Wilkerson, Mihail P. Petkov, Gerald E. Voecks, Catherine S. Lynch, Holly S. Shulman, Santhoshkumar Sundaramoorthy, Amitava Choudhury, Douglas L. Rickman, Michael R. Effinger Aug 2023

Outgassing Behavior And Heat Treatment Optimization Of Jsc-1a Lunar Regolith Simulant, Ryan P. Wilkerson, Mihail P. Petkov, Gerald E. Voecks, Catherine S. Lynch, Holly S. Shulman, Santhoshkumar Sundaramoorthy, Amitava Choudhury, Douglas L. Rickman, Michael R. Effinger

Chemistry Faculty Research & Creative Works

As NASA Strives towards a Long Duration Presence on the Moon, It Has Become Increasingly Important to Learn How to Better Utilize Resources from the Lunar Surface for Everything from Habitats, Vehicle Infrastructure, and Chemical Extraction. to that End, a Variety of Lunar Simulants Have Been Sourced from Terrestrially Available Volcanic Minerals and Glass as Apollo Regolith is Unavailable for Experimentation Needing Large Masses. However, While Mineralogy and Chemical Composition Can Approach that of Lunar Material in These Simulants, There Are Still Distinct Non-Lunar Phases Such as Hydrates, Carbonates, Sulfates, and Clays that Can Cause Simulants to Behave Distinctly Non-Lunar …

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Differential Membrane Binding Of Α/Β-Peptide Foldamers: Implications For Cellular Delivery And Mitochondrial Targeting, Tzong-Hsien Lee, James W. Checco, Tess Malcolm, Chelcie H. Eller, Ronald T. Raines, Samuel H. Gellman, Erinna F. Lee, W. Douglas Fairlie, Marie-Isabel Aguilar Aug 2023

Differential Membrane Binding Of Α/Β-Peptide Foldamers: Implications For Cellular Delivery And Mitochondrial Targeting, Tzong-Hsien Lee, James W. Checco, Tess Malcolm, Chelcie H. Eller, Ronald T. Raines, Samuel H. Gellman, Erinna F. Lee, W. Douglas Fairlie, Marie-Isabel Aguilar

Chemistry Department: Faculty Publications

The intrinsic pathway of apoptosis is regulated by the Bcl-2 family of proteins. Inhibition of the anti-apoptotic members represents a strategy to induce apoptotic cell death in cancer cells. We have measured the membrane binding properties of a series of peptides, including modified α/β-peptides, designed to exhibit enhanced membrane permeability to allow cell entry and improved access for engagement of Bcl-2 family members. The peptide cargo is based on the pro-apoptotic protein Bim, which interacts with all anti-apoptotic proteins to initiate apoptosis. The α/β-peptides contained cyclic β-amino acid residues designed to increase their stability and membrane-permeability. Dual polarisation interferometry was …

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Towards Deposition Of Iron & Nickel Onto Cadmium Selenide/Cadmium Sulfide Nanorods, Rajib Nath Aug 2023

Towards Deposition Of Iron & Nickel Onto Cadmium Selenide/Cadmium Sulfide Nanorods, Rajib Nath

Masters Theses & Specialist Projects

Metal-semiconductor hybrids have been studied extensively as photocatalysts for the watersplitting reaction to generate hydrogen gas and oxygen gas to use as a renewable energy source. The semiconductor component converts light into electrochemical energy, while the metal component provides a site for chemical reactions with water. Here, the choice of metal can have a significant impact on the efficiency of the catalyst. Platinum efficiently catalyzes the watersplitting reaction and is therefore commonly used in metal-semiconductor hybrids to generate hydrogen. Platinum is very expensive, which motivates research into improving less costly metals like iron or nickel that do not have nearly …

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Atomically Dispersed Cu-N3 On Hollow Spherical Carbon Nitride For Acetaminophen Degradation: Generation Of 1o2 From H2o2, Shuoyuan Tian, Yu Yin, Mengxuan Liu, Lei Shi, Shu Zhang, Abdul Hannan Asif, Xuan Li, Mengqiong Liu, Xiaoguang Duan, Shaobin Wang, Hongqi Sun Aug 2023

Atomically Dispersed Cu-N3 On Hollow Spherical Carbon Nitride For Acetaminophen Degradation: Generation Of 1o2 From H2o2, Shuoyuan Tian, Yu Yin, Mengxuan Liu, Lei Shi, Shu Zhang, Abdul Hannan Asif, Xuan Li, Mengqiong Liu, Xiaoguang Duan, Shaobin Wang, Hongqi Sun

Research outputs 2022 to 2026

Discharge of recalcitrant pharmaceuticals into aquatic systems has caused severe impacts on public health and ecosystem. Advanced oxidation processes (AOPs) are effective for eliminating these refractory pollutants, for which single-atom catalysts (SACs) become the state-of-the-art materials owing to the maximized exposure of active metal sites. In this work, hollow spherical graphitic carbon nitride (hsCN) was fabricated to incorporate copper species to develop Fenton-like catalysts for acetaminophen (ACT) removal. Through pyrolysis of supramolecular assemblies derived from melamine-Cu complex and cyanuric acid, single atom Cu-N3 sites were anchored on hsCN by N-coordination to obtain SACu-hsCN. In virtue …

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The Driving Effects Of Common Atmospheric Molecules For Formation Of Clusters: The Case Of Sulfuric Acid, Formic Acid, Hydrochloric Acid, Ammonia, And Dimethylamine, Olivia M. Longsworth, Conor J. Bready, George C. Shields Jul 2023

The Driving Effects Of Common Atmospheric Molecules For Formation Of Clusters: The Case Of Sulfuric Acid, Formic Acid, Hydrochloric Acid, Ammonia, And Dimethylamine, Olivia M. Longsworth, Conor J. Bready, George C. Shields

Open Access Fund Publications

One of the main sources of uncertainty for understanding global warming is understanding the formation of larger secondary aerosols. The beginning stages start with the formation of prenucleation complexes from precursor monomers of acids, bases, and organic molecules. The detailed interactions responsible for prenucleation and subsequent aerosol formation are difficult to decipher experimentally. We present a computational chemistry study of the interactions between three different acid molecules and two different bases. By combining a comprehensive search routine covering many thousands of configurations at the semiempirical level with high level quantum chemical calculations of approximately 1000 clusters for every possible combination …

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The Emergence Of Zerovalent Carbon Compounds From Structural Curiosities To Organocatalysts, Allegra L. Liberman-Martin Jul 2023

The Emergence Of Zerovalent Carbon Compounds From Structural Curiosities To Organocatalysts, Allegra L. Liberman-Martin

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Low-valent main group compounds have reactivity patterns and properties reminiscent of transition metals. While divalent carbon compounds such as carbenes are widely studied ligands and organocatalysts, zerovalent carbon species have received considerably less attention. This perspective highlights the properties and reactivity of zerovalent carbon compounds, focusing on their first applications as organocatalysts for small molecule reduction and polymerization reactions.

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C···O And Si···O Tetrel Bonds: Substituent Effects And Transfer Of The Sif3 Group, Zhihao Niu, Qiaozhuo Wu, Qingzhong Li, Steve Scheiner Jul 2023

C···O And Si···O Tetrel Bonds: Substituent Effects And Transfer Of The Sif3 Group, Zhihao Niu, Qiaozhuo Wu, Qingzhong Li, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The tetrel bond (TB) between 1,2-benzisothiazol-3-one-2-TF3-1,1-dioxide (T = C, Si) and the O atom of pyridine-1-oxide (PO) and its derivatives (PO-X, X = H, NO2, CN, F, CH3, OH, OCH3, NH2, and Li) is examined by quantum chemical means. The Si···O TB is quite strong, with interaction energies approaching a maximum of nearly 70 kcal/mol, while the C···O TB is an order of magnitude weaker, with interaction energies between 2.0 and 2.6 kcal/mol. An electron-withdrawing substituent on the Lewis base weakens this TB, while an electron-donating group has the opposite …

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Enhanced Quantum Chemistry With Machine Learning, Brock Dyer Jul 2023

Enhanced Quantum Chemistry With Machine Learning, Brock Dyer

Physics and Astronomy Summer Fellows

This file is a catalogue of the relevant quantum mechanical and computer programming topics that I learned during the summer which will be helping me to generate an artificial intelligence that will be able to perform computational chemical calculations at a much faster rate and comparable or better accuracy than current methods.

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Carbon Nanotubes Animated, Nicholas Onyemeke Jul 2023

Carbon Nanotubes Animated, Nicholas Onyemeke

Chemistry Summer Fellows

In this project, I implemented the knowledge about carbon nanotubes into an animated short. The animated short is meant to simplify the research so that anyone can understand regardless of their background in science. The research I did was on how nanotubes can be used in the medical field as a measure to inhibit bacteria growth. A nanotube dye solution was synthesized to inoculate bacteria along with an antibiotic solution with the nanotubes. This was done to observe how well the nanotubes can inhibit bacteria growth without the need for a drug compared to the effectiveness when it has a …

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Ortho-Fluoro Effect On The C–C Bond Activation Of Benzonitrile Using Zerovalent Nickel, Sébastien Lachaize, Dominique C. Gallegos, Juliana J. Antonio, Abdurrahman C. Atesin, Tülay A. Ateşin, William D. Jones Jul 2023

Ortho-Fluoro Effect On The C–C Bond Activation Of Benzonitrile Using Zerovalent Nickel, Sébastien Lachaize, Dominique C. Gallegos, Juliana J. Antonio, Abdurrahman C. Atesin, Tülay A. Ateşin, William D. Jones

Chemistry Faculty Publications and Presentations

The effect of fluoro substitution on the C–C bond activation of aromatic nitriles has been studied by reacting a variety of fluorinated benzonitriles with the nickel(0) fragment [Ni(dippe)] and by locating the reaction intermediates and transition-state structures on the potential energy surface by using density functional theory calculations with the [Ni(dmpe)] fragment (dippe = 1,2-bis(diisopropylphosphino)ethane, dmpe = 1,2-bis(dimethylphosphino)ethane). As in the previous reports, the reaction of fluorinated benzonitriles with the [Ni(dippe)] fragment initially formed an η2-nitrile complex, which then converted to the C–CN bond activation product. Thermodynamic parameters for the equilibrium between these complexes have been determined experimentally in both …

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Temperature-Pressure Phase Diagram Of Confined Monolayer Water/Ice At First-Principles Accuracy With A Machine-Learning Force Field, Bo Lin, Jian Jiang, Xiao Cheng Zeng, Lei Li Jul 2023

Temperature-Pressure Phase Diagram Of Confined Monolayer Water/Ice At First-Principles Accuracy With A Machine-Learning Force Field, Bo Lin, Jian Jiang, Xiao Cheng Zeng, Lei Li

Chemistry Department: Faculty Publications

Understanding the phase behaviour of nanoconfined water films is of fundamental importance in broad fields of science and engineering. However, the phase behaviour of the thinnest water film – monolayer water – is still incompletely known. Here, we developed a machine-learning force field (MLFF) at first-principles accuracy to determine the phase diagram of monolayer water/ice in nanoconfinement with hydrophobic walls. We observed the spontaneous formation of two previously unreported high-density ices, namely, zigzag quasi-bilayer ice (ZZ-qBI) and branched-zigzag quasi-bilayer ice (bZZ-qBI). Unlike conventional bilayer ices, few inter-layer hydrogen bonds were observed in both quasi-bilayer ices. Notably, the bZZ-qBI entails a …

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Cationic Divalent Metal Sites (M = Mn, Fe, Co) Operating As Both Nitrene-Transfer Agents And Lewis Acids Toward Mediating The Synthesis Of Three- And Five-Membered N-Heterocycles, Suraj Kumar Sahoo, Brent Harfmann, Lin Ai, Qiuwen Wang, Sudip Mohapatra, Amitava Choudhury, Pericles Stavropoulos Jul 2023

Cationic Divalent Metal Sites (M = Mn, Fe, Co) Operating As Both Nitrene-Transfer Agents And Lewis Acids Toward Mediating The Synthesis Of Three- And Five-Membered N-Heterocycles, Suraj Kumar Sahoo, Brent Harfmann, Lin Ai, Qiuwen Wang, Sudip Mohapatra, Amitava Choudhury, Pericles Stavropoulos

Chemistry Faculty Research & Creative Works

The tripodal compounds [(TMG3trphen)MII-solv](PF6)2 (M = Mn, Fe, Co; solv = MeCN, DMF) and bipodal analogues [(TMG2biphen)MII(NCMe)x](PF6)2 (x = 3 for Mn, Fe; x = 2 for Co) and [(TMG2biphen)MIICl2] have been synthesized with ligands that feature a triaryl- or diarylmethyl-amine framework and superbasic tetramethylguanidinyl residues (TMG). The dicationic M(II) sites mediate catalytic nitrene-transfer reactions between the imidoiodinane PhI═NTs (Ts = tosyl) and a panel of styrenes in MeCN to afford aziridines and low yields of imidazolines (upon …

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Identification Of Unsuccessful Students In General Chemistry, G. Robert Shelton, Joseph M. Simpson, Diana Mason Jul 2023

Identification Of Unsuccessful Students In General Chemistry, G. Robert Shelton, Joseph M. Simpson, Diana Mason

All Faculty Scholarship

The Networking for Science Advancement (NSA) team collected data from multiple general chemistry courses at nine universities within a broad geographic setting in a majority-minority US state. Data include diagnostic scores on the Math-Up Skills Test (MUST), quantitative literacy/quantitative reasoning (QL/QR) quiz, along with student demographics, and overall course grades. From these data the team determined how automaticity skills in procedural arithmetic and quantitative literacy and reasoning can be used to predict success in lower-division chemistry courses. By expanding this dataset, we extended our investigations to discover what characterizes successful and unsuccessful students in general chemistry, first and second semesters …

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Predictability Of The Must (Math-Up Skills Test), Diana Mason, G. Robert Shelton Jul 2023

Predictability Of The Must (Math-Up Skills Test), Diana Mason, G. Robert Shelton

All Faculty Scholarship

In the USA for the most part, completion of a first-semester general chemistry (Chem I) course lays the foundation deemed necessary for understanding second-semester general chemistry (Chem II) topics. Successful completion of Chem I and II gives students permission to progress to organic chemistry I (O-Chem). A series of studies undertaken by the NSA (Networking for Science Advancement) Texas team began in 2016. Texas is one of five majority-minority states in the USA and hosts a significant Hispanic population. The purpose of this research line is to evaluate the influence of basic arithmetic automaticity (what students can do without a …

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Biological Formation Of Ethylene, Robert P. Hausinger, Simahudeen Bathir Jaber Sathik Rifayee, Midhun George Thomas, Shramana Chatterjee, Jian Hu, Christo Christov Jul 2023

Biological Formation Of Ethylene, Robert P. Hausinger, Simahudeen Bathir Jaber Sathik Rifayee, Midhun George Thomas, Shramana Chatterjee, Jian Hu, Christo Christov

Michigan Tech Publications, Part 2

This review summarizes the structures, biochemical properties, and mechanisms of two major biological sources of ethylene, the ethylene-forming enzyme (EFE) and 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase (ACCO). EFE is found in selected bacteria and fungi where it catalyzes two reactions: (1) the oxygen-dependent conversion of 2-oxoglutarate (2OG) to ethylene plus three molecules of CO2/bicarbonate and (2) the oxidative decarboxylation of 2OG while transforming l-arginine to guanidine and l-Δ1-pyrroline-5-carboxylic acid. ACCO is present in plants where it makes the plant hormone by transforming ACC, O2, and an external reductant to ethylene, HCN, CO2, and water. Despite catalyzing distinct chemical reactions, EFE and …

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Study On The Self-Repairing Effect Of Nanoclay In Powder Coatings For Corrosion Protection, Marshall S. Yang, Jinbao Huang, Hui Zhhang, James Noel, Yolanda S. Hedberg, Jian Chen, Ubong Eduok, Ivan Barker, Jeffrey D. Henderson, Chengqian Xian, Haiping Zhang, Jesse Zhu Jul 2023

Study On The Self-Repairing Effect Of Nanoclay In Powder Coatings For Corrosion Protection, Marshall S. Yang, Jinbao Huang, Hui Zhhang, James Noel, Yolanda S. Hedberg, Jian Chen, Ubong Eduok, Ivan Barker, Jeffrey D. Henderson, Chengqian Xian, Haiping Zhang, Jesse Zhu

Chemistry Publications

Powder coatings are a promising, solvent-free alternative to traditional liquid coatings due to the superior corrosion protection they provide. This study investigates the effects of incorporating montmorillonite-based nanoclay additives with different particle sizes into polyester/triglycidyl isocyanurate (polyester/TGIC) powder coatings. The objective is to enhance the corrosion-protective function of the coatings while addressing the limitations of commonly employed epoxy-based coating systems that exhibit inferior UV resistance. The anti-corrosive and surface qualities of the coatings were evaluated via neutral salt spray tests, electrochemical measurements, and surface analytical techniques. Results show that the nanoclay with a larger particle size of 18.38 µm (D50, …

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