Chemistry Commons^™

Extensive Thiol Profiling For Assessment Of Intracellular Redox Status In Cultured Cells By Hplc-Ms/Ms, Jiandong Wu, Anna Chernatynskaya, Annalise Pfaff, Huari Kou, Nan Cen, Nuran Ercal, Honglan Shi

Computer Science Faculty Research & Creative Works

Oxidative stress may contribute to the pathology of many diseases, and endogenous thiols, especially glutathione (GSH) and its metabolites, play essential roles in the maintenance of normal redox status. Understanding how these metabolites change in response to oxidative insult can provide key insights into potential methods of prevention and treatment. Most existing methodologies focus only on the GSH/GSH disulfide (GSSG) redox couple, but GSH regulation is highly complex and depends on several pathways with multiple redox-active sulfur-containing species. In order to more fully characterize thiol redox status in response to oxidative insult, a high-performance liquid chromatography with tandem mass spectrometry …

Discovery Of An Olivine-Type Lithium Manganese Thiophosphate, Limnps4,: Via A Building Block Approach, Srikanth Balijapelly, Kartik Ghosh, Aleksandr V. Chernatynskiy, Amitava Choudhury

Physics Faculty Research & Creative Works

An olivine-type orthothiophospate LiMnPS4 has been synthesized for the first time through a building block approach by reacting preformed ternary lithium thiophospate with MnCl2. Diffuse reflectance measurements show an optical band gap of 2.36 eV, which is further confirmed by DFT calculations. Irreversible weak ferromagnetic ordering and metamagnetism are verified through preliminary magnetic measurements.

Solvation Of Isoelectronic Halide And Alkali Metal Ions By Argon Atoms, Carly A. Rock, Sarah N. Arradondo, Gregory S. Tschumper

Chemistry Faculty Research & Creative Works

This work systematically examines the interactions of alkali metal cations and their isoelectronic halide counterparts with up to six solvating Ar atoms (M+Arn and X–Arn, where M = Li, Na, K, and Rb; X = H, F, Cl, and Br; and n = 1–6) via full geometry optimizations with the MP2 method and robust, correlation-consistent quadruple-ζ (QZ) basis sets. 116 unique M+Arn and X–Arn stationary points have been characterized on the MP2/QZ potential energy surface. To the best of our knowledge, approximately two dozen of these stationary points have been reported here for the first time. Some of these new …

Super-Adsorbent Hydrogels For Removal Of Methylene Blue From Aqueous Solution: Dye Adsorption Isotherms, Kinetics, And Thermodynamic Properties, Buddhabhushan Salunkhe, Thomas P. Schuman

Chemistry Faculty Research & Creative Works

Removal of dyes through adsorption from wastewater has gained substantial interest in recent years, especially in development of hydrogel-based adsorbents, owing to their easy use and economical nature. The aim of the present study was to design a super-adsorbent hydrogel based on sodium styrene sulfonate (NaSS) monomer for removal of dyes like methylene blue (MB). NaSS displays both an aromatic ring and strongly ionic group in its monomer structure that can enhance adsorption capacity. Poly (sodium styrene sulfonate-co-dimethylacrylamide) hydrogels were prepared by solution free radical polymerization using gelatin meth acryloyl (GelMA) as crosslinker, creating a highly porous, three-dimensionally crosslinked polymer …

Erratum: Physicochemical Insights Of Irradiation-Enhanced Hydroxyl Radical Generation From Zno Nanoparticles(Toxicology Research Doi: 10.1039/C5tx00384a), Qingbo Yang, Tien Sung Lin, Casey Burton, Sungho Park, Yinfa Ma

Electrical and Computer Engineering Faculty Research & Creative Works

In the originally published version of this manuscript, the fourth author's name is incorrect. The name should read "Sungho Park", instead of "Sung-Ho Park". These details have been corrected only in this corrigendum to preserve the published version of record.

Systematic Evaluation Of A Novel Self-Healing Poly(Acrylamide-Co-Vinyl Acetate)/Alginate Polymer Gel For Fluid Flow Control In High Temperature And High Salinity Reservoirs, Jingyang Pu, Baojun Bai, Thomas P. Schuman

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Preferential fluid flow often occurs when water and CO₂ is injected into mature oilfields, sig-nificantly reducing their injection efficiency. Particle gels have been evaluated and applied to control the short circulation problems. This study systematically investigated a novel poly(acrylamide-co-vinyl acetate)/alginate-based interpenetrated gel system (Alg-IPNG) which is designed to control the preferential fluid flow problems in high-temperature reservoirs. Chromium acetate was incorporated into the gel system to provide the delayed crosslinking feature of the particle gels. The alginate polymer system can also take advantage of the Ca²⁺ ions in the formation water, which exist in most reservoirs, to reinforce …

Calibration Of Gas Flow Meters Using Choked Flow And An Evacuated Vessel, Max B. Trueblood, Otmar Schmid, Nicholas Altese, Christian J. Hurst, Wenyan Liu, Teresa Gelles, Steven C. Achterberg, Philip D. Whitefield, Donald E. Hagen

Chemistry Faculty Research & Creative Works

The measurement of gas flow rates is of great importance in a wide range of modern technologies. This paper introduces a simple, yet accurate technique for in-house calibration of gas FMs (mass and volumetric) even under harsh environmental conditions such as encountered during field measurement campaigns. The method requires only readily available, low cost components: a vessel of known volume, an air pump, a pressure sensor and a metal plate orifice or a needle valve to act as a CO. The unique property of choked flow in the CO is used here for flow calibration. In the method presented here …

Preparation And Pharmacokinetic Characterization Of An Anti-Virulence Compound Nanosuspensions, Nan Wang, Feng Qi, Xiaolong He, Honglan Shi, David W. Anderson, Hao Li, Hongmin Sun

Chemistry Faculty Research & Creative Works

Antibiotic resistance has become a worldwide public health threat due to the rapid evolu-tion and spread of antibiotic-resistant bacteria. CCG-211790 is a novel anti-virulence compound that does not kill bacteria but could ameliorate human diseases by inhibiting expression of virulence factors, thereby applying less selection pressure for antibiotic resistance. However, its potential clinical use is restricted because of its poor aqueous solubility, resulting in formulation challenges. Nanosuspension technology is an effective way to circumvent this problem. Nanosuspensions of CCG-211790 with two different particle sizes, NanoA (315 ± 6 nm) and NanoB (915 ± 24 nm), were prepared using an antisolvent …

Experimental Data On Water Soluble Polymers Thermal And Hydrolytic Stability, Reactivity Ratios Of Monomers And Frr Calculation For Thermally Stable Preformed Particle Gels Therefrom, Buddhabhushan Salunkhe, Thomas P. Schuman, Ali Al Brahim, Baojun Bai

Chemistry Faculty Research & Creative Works

Experimental data on water soluble polymer thermal and hydrolytic stability in acidic, neutral and basic pH conditions in aqueous solution is presented. Thermal and hydrolytic stability of polymer aqueous solutions were monitored in variable pH medium by aging at 130 °C temperature for different aging time. Polymer viscosity measurements were performed periodically for 3 months. Furthermore, this data can serve as a basis of monomer selection for thermally stable hydrogels for applications like oil recovery, hydrogel coatings for steam sterilized medical devices and other applications. Reactivity ratios were determined for monomers associated to the most stable polymers using ¹H …

Characterization Of A Nitro-Forming Enzyme Involved In Fosfazinomycin Biosynthesis, Hannah Valentino, Pablo Sobrado

Chemistry Faculty Research & Creative Works

N-hydroxylating monooxygenases (NMOs) are a subclass of flavin-dependent enzymes that hydroxylate nitrogen atoms. Recently, unique NMOs that perform multiple reactions on one substrate molecule have been identified. Fosfazinomycin M (FzmM) is one such NMO, forming nitrosuccinate from aspartate (Asp) in the fosfazinomycin biosynthetic pathway in someStreptomycessp. This work details the biochemical and kinetic analysis of FzmM. Steady-state kinetic investigation shows that FzmM performs a coupled reaction with Asp (kcat, 3.0 ± 0.01 s-1) forming nitrosuccinate, which can be converted to fumarate and nitrite by the action of FzmL. FzmM displays a 70-fold higherkcat/KMvalue for NADPH compared to NADH and has …

Genotype, Age, Genetic Background, And Sex Influence Epha2-Related Cataract Development In Mice, Alpana Dave, Jamie E. Craig, Mohammad Alamein, Karina Skrzypiec, Justin Beltz, Annalise Pfaff, Kathryn P. Burdon, Nuran Ercal, Robb U. De Iongh, Shiwani Sharma

Chemistry Faculty Research & Creative Works

PURPOSE. Age-related cataract is the leading cause of blindness worldwide. Variants in the EPHA2 gene increase the disease risk, and its knockout in mice causes cataract. We investigated whether age, sex, and genetic background, risk factors for age-related cataract, and Epha2 genotype influence Epha2-related cataract development in mice.

METHODS. Cataract development was monitored in Epha2⁺/⁺, Epha2^+/-, and Epha2^-/- mice (Epha2^{Gt(KST085)Byg}) on C57BL/6J and FVB:C57BL/6J (50:50) backgrounds. Cellular architecture of lenses, endoplasmic reticulum (ER) stress, and redox state were determined using histological, molecular, and analytical techniques.

RESULTS. Epha2^-/- and Epha2^{+/- …}

Torsional Profiles Of Thiophene And Furan Oligomers: Probing The Effects Of Heterogeneity And Chain Length, Morgan A. Perkins, Laura M. Cline, Gregory S. Tschumper

Chemistry Faculty Research & Creative Works

A systematic analysis of the torsional profiles of 55 unique oligomers composed of two to four thiophene and/or furan rings (n = 2 to 4) has been conducted using three density functional theory (DFT) methods along with MP2 and three different coupled-cluster methods. Two planar or quasi-planar minima were identified for each n = 2 oligomer system. In every case, the torsional angle (τ) between the heteroatoms about the carbon-carbon bond connecting the two rings is at or near 180° for the global minimum and 0° for the local minimum, referred to as anti and syn conformations, respectively. These oligomers …

Structural And Biochemical Characterization Of The Flavin-Dependent Siderophore-Interacting Protein From Acinetobacter Baumannii, Hannah Valentino, David A. Korasick, Tabbetha J. Bohac, Justin A. Shapiro, Timothy A. Wencewicz, John J. Tanner, Pablo Sobrado

Chemistry Faculty Research & Creative Works

Acinetobacter baumannii is an opportunistic pathogen with a high mortality rate due to multi-drug-resistant strains. The synthesis and uptake of the iron-chelating siderophores acinetobactin (Acb) and preacinetobactin (pre-Acb) have been shown to be essential for virulence. Here, we report the kinetic and structural characterization of BauF, a flavin-dependent siderophore-interacting protein (SIP) required for the reduction of Fe (III) bound to Acb/pre-Acb and release of Fe(II). Stopped-flow spectrophotometric studies of the reductive half-reaction show that BauF forms a stable neutral flavin semiquinone intermediate. Reduction with NAD(P)H is very slow (kobs, 0.001 s-1) and commensurate with the rate of reduction by photobleaching, …

Continuous Measurement Of Reactive Oxygen Species Inside And Outside Of A Residential House During Summer, Azin Eftekhari, Claire F. Fortenberry, Brent J. Williams, Michael J. Walker, Audrey Dang, Annalise Pfaff, Nuran Ercal, Glenn C. Morrison

Chemistry Faculty Research & Creative Works

Reactive oxygen species (ROS) are an important contributor to adverse health effects associated with ambient air pollution. Despite infiltration of ROS from outdoors, and possible indoor sources (eg, combustion), there are limited data available on indoor ROS. In this study, part of the second phase of Air Composition and Reactivity from Outdoor aNd Indoor Mixing campaign (ACRONIM-2), we constructed and deployed an online, continuous, system to measure extracellular gas- and particle-phase ROS during summer in an unoccupied residence in St. Louis, MO, USA. Over a period of one week, we observed that the non-denuded outdoor ROS (representing particle-phase ROS and …

Copper Selenide As Multifunctional Non-Enzymatic Glucose And Dopamine Sensor, Harish Singh, Jillian Bernabe, Justin Chern, Manashi Nath

Chemistry Faculty Research & Creative Works

Cu₂Se, synthesized through one-pot hydrothermal synthesis, was identified as highly efficient bifunctional sensor for co-detection of glucose and dopamine with high selectivity. As-synthesized copper selenide could electro-oxidize glucose and dopamine at different applied potentials. Glucose oxidation was observed at 0.35 V while dopamine oxidized at 0.2 V. This copper selenide-based non-enzymatic sensor showed high sensitivity for both glucose (15.341 mA mM^-1 cm^-2) and dopamine (12.43 μA μM^-1 cm^-2) with low limit of detection (0.26 μM and 84 nM). Such high sensitivity and low LOD makes this sensor attractive for possible detection of …

Temperature-Dependent Rotationally Inelastic Collisions Of Ohˉ And He, Eric S. Endres, Steve Ndengué, Olga Lakhmanskaya, Seunghyun Lee, Francesco A. Gianturco, Richard Dawes, Roland Wester

Chemistry Faculty Research & Creative Works

We have studied the fundamental rotational relaxation and excitation collision of OHˉJ = 0 ↔ 1 with helium at different collision energies. Using state-selected photodetachment in a cryogenic ion trap, the collisional excitation of the first excited rotational state of OHˉ has been investigated and absolute inelastic collision rate coefficients have been extracted for collision temperatures between 20 and 35 K. The rates are compared with accurate quantum scattering calculations for three different potential-energy surfaces. Good agreement is found within the experimental accuracy, but the experimental trend of increasing collision rates with temperature is only in part reflected in the …

Water Splitting By Mixed Chalcogenide Catalysts, Isabella Feltenstein

Undergraduate Research Conference at Missouri S&T

The depleting supply of fossil fuels has led to deeper investigation of water-splitting as a sustainable energy source. Specifically, using transition metal chalcogenides to catalyze the water-splitting reaction through oxygen and hydrogen evolution reactions. While the decreasing electronegativity of the chalcogenide group increases their activity, it also decreases their stability, leading to the investigation of mixed anion chalcogenides in order to keep both the stability and activity high. This research will further the understanding and efficiency of water-splitting for energy storage and inspire more research in the future. In these experiments, cobalt telluroselenide (Cox-Tey-Sez) and nickel telluroselenide (Nix-Tey-Sez) catalysts were …

Chemically Resolved Nuclear Spin Relaxation, Megan Sly

Undergraduate Research Conference at Missouri S&T

In Nuclear Magnetic Resonance (NMR) Spectroscopy, the excitation of nuclear spins is used to generate spectra of radiofrequency resonance signals. The signal frequencies are typically used to determine the structure of chemical compounds, while the relaxation of the spins to thermodynamic equilibrium provides useful information about the molecular vicinity of a material. When a chemical compound occurs in different molecular environments, a single resonance signal can have multiple relaxation times. To quantify how much material is in how many different environments, a multi-exponential analysis was developed resolving resonance signals and relaxation times in two-dimensional contour plots. Samples of known resonance …

Amorphous Carbon Aerogels From Xerogel Powders, Daniel Greenan

Undergraduate Research Conference at Missouri S&T

Carbon aerogels are well known for their high surface areas and high porosities. Their applications have been demonstrated in a wide range of areas such as CO2 capture, electrodes for electrochemical cells, etc. They are typically made from pyrolysis of carbonizable polymeric aerogels, which in turn are synthesized via sol-gel methods. Preparation of those polymeric aerogels involves supercritical fluid drying of wet-gels by replacing the pore-filling solvent with liquid CO2 that can be vented off as a gas, thus allowing pores to retain their shape and size. In contrast, here a new alternative route is proposed for the synthesis of …

Enantioselective Nickel-Catalyzed Alkyne-Azide Cycloaddition By Dynamic Kinetic Resolution, En Chih Liu, Joseph J. Topczewski

Chemistry Faculty Research & Creative Works

The triazole heterocycle has been widely adopted as an isostere for the amide bond. Many native amides are α-chiral, being derived from amino acids. This makes α-N-chiral triazoles attractive building blocks. This report describes the first enantioselective triazole synthesis that proceeds via nickel-catalyzed alkyne-azide cycloaddition (NiAAC). This dynamic kinetic resolution is enabled by a spontaneous [3,3]-sigmatropic rearrangement of the allylic azide. The 1,4,5-trisubstituted triazole products, derived from internal alkynes, are complementary to those commonly obtained by the related CuAAC reaction. Initial mechanistic experiments indicate that the NiAAC reaction proceeds through a monometallic Ni complex, which is distinct from the CuAAC …

Metal Foils With Ordered Crystal Structure And Method For Producing Metal Foils, Jay A. Switzer

Chemistry Faculty Research & Creative Works

A method for producing a metal foil comprising depositing metal onto an oxidizable substrate to form a metal film on the substrate; oxidizing the substrate at an interface between the metal film and the substrate; and removing the metal film from the substrate to yield a metal foil. A method for forming a thin metal film comprising pre-polarizing a single-crystal Si substrate by application of a potential which is negative of a potential at which Si oxidizes, which pre-polarization occurs in the presence of metal ions to form metal growth nucleation sites on the substrate, followed by application of a …

High-Throughput Screen For Inhibitors Of The Type Iv Pilus Assembly Atpase Pilb, Keane J. Dye, Nancy J. Vogelaar, Pablo Sobrado, Zhaomin Yang

Chemistry Faculty Research & Creative Works

The bacterial type IV pilus (T4P) is a prominent virulence factor in many significant human pathogens, some of which have become increasingly antibiotic resistant. Antivirulence chemotherapeutics are considered a promising alternative to antibiotics because they target the disease process instead of bacterial viability. However, a roadblock to the discovery of anti-T4P compounds is the lack of a high throughput screen (HTS) that can be implemented relatively easily and economically. Here, we describe the first HTS for the identification of inhibitors specifically against the T4P assembly ATPase PilB in vitro. Chloracidobacterium thermophilum PilB (CtPilB) had been demonstrated to have robust ATPase …

Achieving Superlubricity With 2d Transition Metal Carbides (Mxenes) And Mxene/Graphene Coatings, S. Huang, K. C. Mutyala, A. V. Sumant, Vadym Mochalin

Chemistry Faculty Research & Creative Works

Two-dimensional (2D) materials have demonstrated unique friction and antiwear properties unmatched by their bulk (3D) counterparts. A relatively new, large and quickly growing family of two-dimensional early transition metal carbides and nitrides (MXenes) present a great potential in different applications. There is a growing interest in understanding the mechanical and tribological properties of MXenes, however, no report of MXene superlubricity in a solid lubrication process at the macroscale has been presented. Here we investigate the tribological properties of two-dimensional titanium carbide (Ti₃C₂) MXene deposited on SiO₂-coated silicon (Si) substrates subjected to wear by sliding …

Disaggregation Of Nanodiamond Particles, Vadym Mochalin, Atsushi Kume, Yoshihiro Inamoto, Masumi Hashimoto

Chemistry Faculty Research & Creative Works

Methods for disaggregating nanodiamond clusters, for example, by using sonication to break apart nanodiamond aggregates in an aqueous slurry having an alkaline pH. Compositions, such as aqueous nanodiamond dispersions and dry particulate compositions can be produced using these methods.

A Molecular Tetrahedral Cobalt-Seleno-Based Complex As An Efficient Electrocatalyst For Water Splitting, Ibrahim Munkaila Abdullahi, Jahangir Masud, Polydoros Chrisovalantis Ioannou, Eleftherios Ferentinos, Panayotis Kyritsis, Manashi Nath

Chemistry Faculty Research & Creative Works

The cobalt-seleno-based coordination complex, [Co{(SePⁱPr₂)₂N}₂], is reported with respect to its catalytic activity in oxygen evolution and hydrogen evolution reactions (OER and HER, respectively) in alkaline solutions. An overpotential of 320 and 630 mV was required to achieve 10 mA cm^-2 for OER and HER, respectively. The overpotential for OER of this CoSe₄-containing complex is one of the lowest that has been observed until now for molecular cobalt(II) systems, under the reported conditions. In addition, this cobalt-seleno-based complex exhibits a high mass activity (14.15 A g^-1) and …

Interplay Between Oxo And Fluoro In Vanadium Oxyfluorides For Centrosymmetric And Non-Centrosymmetric Structure Formation, Prashanth Sandineni, Amitava Choudhury, Hooman Yaghoobnejad Asl, Weiguo Zhang, P. Shiv Halasyamani, Kartik Ghosh

Chemistry Faculty Research & Creative Works

Herein, we report the syntheses of two lithium-vanadium oxide-fluoride compounds crystallized from the same reaction mixture through a time variation experiment. A low temperature hydrothermal route employing a viscous paste of V₂O₅, oxalic acid, LiF, and HF allowed the crystallization of one metastable phase initially, Li₂VO_0.55 (H₂O)_0.45F₅·2H₂O (I), which on prolonged heating transforms to a chemically similar yet structurally different phase, Li₃VOF₅ (II). Compound I crystallizes in centrosymmetric space group, I2/a with a = 6.052(3), b = 7.928(4), …

Physicochemical Properties And Formulation Development Of A Novel Compound Inhibiting Staphylococcus Aureus Biofilm Formation, Nan Wang, Feng Qi, Haqing Yu, Bryan D. Yestrepsky, Scott D. Larsen, Honglan Shi, Juan Ji, David W. Anderson, Hao Li, Hongmin Sun

Chemistry Faculty Research & Creative Works

The emergence of antibiotic resistance over the past several decades has given urgency to new antibacterial strategies that apply less selective pressure. A new class of anti-virulence compounds were developed that are active against methicillin-resistant Staphylococcus aureus (MRSA), by inhibiting bacterial virulence without hindering their growth to reduce the selective pressure for resistance development. One of the compounds CCG-211790 has demonstrated potent anti-biofilm activity against MRSA. This new class of anti-virulence compounds inhibited the gene expression of virulence factors involved in biofilm formation and disrupted the biofilm structures. In this study, the physicochemical properties of CCG- 211790, including morphology, solubility …

Coating Compositions And Methods For Using The Same, Fateme Rezaei, Thomas P. Schuman, Glenn Morrison

Chemical and Biochemical Engineering Faculty Research & Creative Works

Coating compositions and methods for using the same are disclosed. The coating compositions can include an aminosilica adsorbent. The coating compositions can adsorb CO₂.

Collisional Excitation Of Interstellar Pn By H₂: New Interaction Potential And Scattering Calculations, Benjamin Desrousseaux, Ernesto Quintas-Sánchez, Richard Dawes, Sarantos Marinakis, François Lique

Chemistry Faculty Research & Creative Works

Rotational excitation of interstellar PN molecules induced by collisions with H₂ is investigated. We present the first ab initio four-dimensional potential energy surface (PES) for the PN-H₂ van der Waals system. The PES was obtained using an explicitly correlated coupled cluster approach with single, double, and perturbative triple excitations [CCSD(T)-F12b]. The method of interpolating moving least squares was used to construct an analytical PES from these data. The equilibrium structure of the complex was found to be linear, with H₂ aligned at the N end of the PN molecule, at an intermolecular separation of 4.2 Å. The …

Biochemical Characterization Of The Two-Component Flavin-Dependent Monooxygenase Involved In Valanimycin Biosynthesis, Hao Li, Benedicta Forson, Meital Eckshtain-Levi, Hannah Valentino, Julia S. Martín Del Campo, John J. Tanner, Pablo Sobrado

Chemistry Faculty Research & Creative Works

The flavin reductase (FRED) and isobutyl amine N-hydroxylase (IBAH) from Streptomyces viridifaciens constitute a two-component, flavin-dependent monooxygenase system that catalyzes the first step in valanimycin biosynthesis. FRED is an oxidoreductase that provides the reduced flavin to IBAH, which then catalyzes the hydroxylation of isobutyl amine (IBA) to isobutyl hydroxylamine (IBHA). In this work, we used several complementary methods to investigate FAD binding, steady-state and rapid reaction kinetics, and enzyme-enzyme interactions in the FRED: IBAH system. The affinity of FRED for FADox is higher than its affinity for FADred, consistent with its function as a flavin reductase. Conversely, IBAH binds FADred …