Chemistry Commons^™

Highly Crystalline Nickel Borate Nanorods As Oxygen Evolution Reaction Electrocatalysts, Xi Xu, Juan Liu, Hua-Zong Wu, Wen-Jie Jiang

Journal of Electrochemistry

Hydrogen energy, a kind of clean and renewable energy, is considered to be the solution to the problems of energy crisis and environmental deterioration. Electrochemical water splitting is an efficient and promising technology for the production of high-purity hydrogen. However, oxygen evolution reaction (OER) at the anode of water electrolyzer limits the efficiency of water splitting due to the high overpotential. Therefore, the challenges still remain for the exploration of highly active, stable and low-cost catalysts with superior activity for OER. Herein, nickel borate nanorods with high crystallinity were prepared via high-temperature calcination. The as-obtained nickel borate nanorods with 2 …

Influences Of Na-Mn Ratio On Electrochemical Performances And Intercalation-Deintercalation Processes Of Sodium Ion In NaXMno2, Yong-Chun Xie, Cheng Wang, Fang Jiang, Yang Yang, Jing Su, Yun-Fei Long, Yan-Xuan Wen

Journal of Electrochemistry

In this work, Na_xMnO₂ was synthesized by a solid-state reaction. The influences of Na:Mn ratio on the structure, morphology and electrochemical performance, and sodium ion intercalation/deintercalation processes were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge-discharge test. The prepared Na_xMnO₂ was mainly composed of Na_0.7MnO₂ and Na_0.91MnO₂, and the content of Na_0.91MnO₂ increased with the increase of Na:Mn ratio. However, the activation energy values of surface membrane diffusion, interfacial electrochemical reaction and …

High-Dimensional Isotope Relationships, Yuyang He

LSU Doctoral Dissertations

High-dimensional isotope relationships describes the relationships of two or more element or position-specific (PS) elements in the same molecule or ion. It provides us more powerful tools to study reaction mechanisms and dynamics. Chapter 1 is about dual or multiple stable isotope relationship on δ-δ (or δ'-δ') space. While temporal data sampled from a closed-system can be treated by a Rayleigh Distillation Model (RDM), spatial data should be treated by a Reaction-Transport Model (RTM). Here we compare the results of a closed-system RDM to a RTM for systems with diffusional mass transfer by simulating the trajectories on nitrate's δ'^{18 …}

Multi-Stimuli-Responsive Self-Immolative Polymer Assemblies, Rebecca E. Yardley, Elizabeth R. Gillies

Chemistry Publications

Self-immolative polymers (SIPs) undergo depolymerization in response to the cleavage of stimuli-responsive end-caps from their termini. Some classes of SIPs, including polycarbamates, have depolymerization rates that depend on environmental factors such as solvent and pH. In previous work, hydrophobic SIPs have been incorporated into amphiphilic block copolymers and used to prepare nanoassemblies. However, stimuli-responsive hydrophilic blocks have not previously been incorporated. In the current work, we synthesized amphiphilic copolymers composed of a hydrophobic polycarbamate SIP block and a hydrophilic poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) block connected by a UV light-responsive linker end-cap. It was hypothesized that after assembly of the block copolymers …

Modulating Restriction Endonuclease Activities And Specificities Using Neutral Detergents, Lori H. Conlan, Thomas J. José, Kevin C. Thornton, Cynthia M. Dupureur

Educator Preparation & Leadership Faculty Works

It is well known that type II restriction enzyme activities and specificities can be modulated by altering solution conditions. The addition of co-solvents such as dimethyl sulfoxide (DMSO), alcohols and polyols can promote star activity, which is the cleavage of non-cognate sequences. While neutral detergents are often used to control protein aggregation, little is known about the effect of neutral detergents on restriction enzyme activities and specificities. We report here that BamHI, BglI, BglII, EcoRI, EcoRV, HindIII, MluI, PvuII, SalI and XhoI restriction endonucleases are remarkably tolerant of high concentrations …

Electrospray Ionization Of Polypropylene Glycol: Rayleigh-Charged Droplets, Competing Pathways, And Charge State-Dependent Conformations., Quentin Duez, Haidy Metwally, Lars Konermann

Chemistry Publications

Recent molecular dynamics (MD) simulations from various laboratories have advanced the general understanding of electrospray ionization (ESI)-related processes. Unfortunately, computational cost has limited most of those previous endeavors to ESI droplets with radii of ∼3 nm or less, which represent the low end of the size distribution in the ESI plume. The current work extends this range by conducting simulations on aqueous ESI droplets with radii of 5.5 nm (∼23 000 water molecules). Considering that computational cost increases with r⁶, this is a significant step forward. We focused on the ESI process for polypropylene glycol (PPG) which is …

Chain Ejection Model For Electrospray Ionization Of Unfolded Proteins: Evidence From Atomistic Simulations And Ion Mobility Spectrometry., Haidy Metwally, Quentin Duez, Lars Konermann

Chemistry Publications

The ion evaporation model (IEM) and the charged residue model (CRM) represent cornerstones of any discussion related to the mechanism of electrospray ionization (ESI). Molecular dynamics (MD) simulations have confirmed that small ions such as Na⁺ are ejected from the surface of aqueous ESI droplets (IEM), while folded proteins in native ESI are released by water evaporation to dryness (CRM). ESI of unfolded proteins yields [M + zH] ^z+ ions that are much more highly charged than their folded counterparts. A chain ejection model (CEM) has been proposed to account for the protein ESI behavior under such non-native conditions …

Pre- And Post-Research Group Selection: Evolving Roles For Chemistry Librarians, Sarah Jeong, Kiyomi D. Deards

University of Nebraska-Lincoln Libraries: Presentations

Librarian consultations with research groups, flipped classroom exercises, active learning, and Just-In-Time instruction sessions are increasing at public and private doctoral granting universities at a time when many library staffs are shrinking. As the needs and points of contact with graduate students evolve it will be critical for the depth of knowledge and resources of chemistry librarians to be understood and shared both in-person and on-demand online. This presentation will outline the strategies used to meet the evolving needs of chemistry graduate students as they move from pre-research group selection into established research groups.

Sintering-Induced Nucleation And Growth Of Noble Metal Nanoparticles For Plasmonic Resonance Ceramic Color, Nathan Dinh, Michael C. Leopold, Ryan Coppage

Chemistry Faculty Publications

This study demonstrates the formation of nanoparticles (NPs) from metal salts within ceramic glazes, such that the use of this colorant technology is more accessible to artisans, employs less metal content, is less environmentally harmful, and allows for the use of traditional kilns. Gold NPs have been demonstrated to possess a specific, low material loading use as a ceramic glaze colorant via plasmon resonance. Pre-synthesized gold NPs that are added to ceramic glazes have been found to significantly change in size after firing in both reductive and oxidative atmospheres, but still maintain some size relationships and color properties. Unfortunately, it …

Radioiodinated Compounds, Stephen Dimagno, Bao Hu

Department of Chemistry: Faculty Publications

This disclosure relates to reagents and methods useful in the synthesis of aryl iodines ,for example , in the preparation of iodine labeled radiotracers . The reagents and methods provided herein may be used to access a broad range of compounds , including aromatic compounds , heteroaromatic compounds , amino acids , nucleotides , and synthetic com pounds .

P62-Dependent Phase Separation Of Patient-Derived Keap1 Mutations And Nrf2, E. W. Cloer, P. F. Siesser, E. M. Cousins, D Goldfarb, D. D. Mowrey, Joseph S. Harrison, S. J. Weir, N. V. Dokholyan, M. B. Major

College of the Pacific Faculty Articles

Cancer-derived loss-of-function mutations in the KEAP1 tumor suppressor gene stabilize the NRF2 transcription factor, resulting in a pro-survival gene expression program that alters cellular metabolism and neutralizes oxidative stress. In a recent genotype-phenotype study, we classified 40% of KEAP1 mutations as ANCHOR mutants. By immunoprecipitation, these mutants bind more NRF2 than wild-type KEAP1 and ubiquitylate NRF2, but are incapable of promoting NRF2 degradation. BioID-based protein interaction studies confirmed increased abundance of NRF2 within the KEAP1 ANCHOR mutant complexes with no other statistically significant changes to the complexes. Discrete molecular dynamic simulation modeling and limited proteolysis suggest that the ANCHOR mutations …

Determination Of Polar Solvents By Static Headspace Extraction – Gas Chromatography (She-Gc), Michael Sithersingh

Seton Hall University Dissertations and Theses (ETDs)

ABSTRACT

The term “headspace” is defined as the vapor that forms above or around a liquid or solid sample in a closed container. Usually, the vapor is above the liquid or solid at the top of the container, hence the term headspace. Headspace sampling is a method for separating volatile materials that may be extracted from a more solid sample matrix and then analyzed using gas chromatography. Headspace extraction refers to the collection and analysis of the vapor phase in the container. The Static Headspace Extraction – Gas Chromatography (SHE-GC) technique has been used since the early days of Gas …

Graphene-Based Materials For The Fast Removal Of Cytokines From Blood Plasma, Mykola Seredych, Bernard Haines, Viktoriia Sokolova, Paul Cheung, Fayan Meng, Lon Stone, Lyuba Mikhalovska, Sergey Mikhalovsky, Vadym Mochalin, Yury Gogotsi

Chemistry Faculty Research & Creative Works

There is a range of medical conditions, which include acute organ failure, bacterial and viral infection, and sepsis, that result in overactivation of the inflammatory response of the organism and release of proinflammatory cytokines into the bloodstream. Fast removal of these cytokines from blood circulation could offer a potentially efficient treatment of such conditions. This study aims at the development and assessment of novel biocompatible graphene-based adsorbents for blood purification from proinflammatory cytokines. These graphene-based materials were chosen on the basis of their surface accessibility for small molecules further facilitated by the interlayer porosity, which is comparable to the size …

1h And 13c Nmr Assignments For (N-Methyl)-(−)-(Α)-Isosparteinium Iodide And (N-Methyl)-(−)-Sparteinium Iodide, Kavoos Kolahdouzan, O. Maduka Ogba, Daniel J. O'Leary

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

(‒)-Sparteine (1) and (–)-(α)-isosparteine (2) are members of the lupine alkaloid family.^[1-2] Sparteine has found extensive use in asymmetric organic transformations, including lithiations^[3] and Pd-catalyzed oxidations.^[4-7] (α)-Isosparteine, which can be made from sparteine, has been utilized as a chiral ligand for a limited number of stereoselective reactions.^[8-9] The two compounds differ in that 1 displays an exo-endo arrangement of the bridgehead hydrogens at C-11 and C-6, respectively, while 2 retains an exo-exo arrangement of these atoms (Figure 1). This study is focused on assigning 1H chemical shifts and coupling constants and 13C chemical shifts for N-methyl …

Synthesis Of The Complex Salt With Triphenylphosphine Bromide, Х Haitbayev,, X. Babaev, I Yuldashev,

Scientific journal of the Fergana State University

This article affirms that one of the main factors for increasing the yield of fruit trees is their protection from pests and diseases. In recent years, plant protection has paid great attention to the use of harmless biological control methods for the environment, humans and animals. An example is the use of the use of pheromones, which can be separated from different insects. Practical significance is the production and use in practice of pheromones of insect pests by chemical methods, which adversely affect the plant world.

Synthesis Of The Complex Salt With Triphenylphosphine Bromide, Х Haitbayev,, X. Babaev, I Yuldashev,

Scientific journal of the Fergana State University

This article affirms that one of the main factors for increasing the yield of fruit trees is their protection from pests and diseases. In recent years, plant protection has paid great attention to the use of harmless biological control methods for the environment, humans and animals. An example is the use of the use of pheromones, which can be separated from different insects. Practical significance is the production and use in practice of pheromones of insect pests by chemical methods, which adversely affect the plant world.

Building On Nature: Spectroscopic Studies Of Photosynthesis-Inspired Pigments, Fused Light Harvesting Proteins, And Bacterial Reaction Center Mutants, Kaitlyn Faries

Arts & Sciences Graduate Student Theses and Dissertations

Photosynthesis is the dominant form of solar energy conversion on the planet, making it critical to understand the fundamentals of the process in order to effectively mimic and improve upon it for human energy needs. The initial stages of photosynthesis include light harvesting and chemical conversion of that harvested energy via electron transport, with both of these stages relying on pigments (or chromophores) such as chlorophyll and specific protein architectures for the processes. In this work, the fundamental underpinnings of photosynthetic light harvesting and electron transport are explored via spectroscopy of various photosynthetic systems with altered natural pigments and proteins. …

Instrumentation For Cryogenic Dynamic Nuclear Polarization And Electron Decoupling In Rotating Solids, Faith Joellen Scott

Arts & Sciences Graduate Student Theses and Dissertations

Dynamic nuclear polarization (DNP) increases the sensitivity of nuclear magnetic resonance (NMR) using the higher polarization of electron radical spins compared to nuclear spins. The addition of electron radicals for DNP to the sample can cause hyperfine broadening, which decreases the resolution of the NMR resonances due to hyperfine interactions between electron and nuclear spins. Electron decoupling has been shown to attenuate the effects of hyperfine coupling in rotating solids. Magic angle spinning (MAS) DNP with electron decoupling requires a high electron Rabi frequency provided by a high-power microwave source such as a frequency-agile gyrotron. This dissertation describes the development …

An Nmr Study Of Co2 Dynamics And Structural Characterization Of Porous Materials, Robert M. Marti

Arts & Sciences Graduate Student Theses and Dissertations

Nuclear magnetic resonance (NMR) has proven to be a versatile and powerful analytical tool to study many areas of interest to the scientific community, such as molecular dynamics and structural characterization. In this dissertation, NMR was used as a probe for CO2 dynamics in metal-organic frameworks. Variable temperature (VT) NMR was used to determine molecular dynamics of CO2, going as low as 8 K. In the fast motion regime, where the CO2 hopping rate is fast compared to the NMR experiment time, 13CO2 inside of Mg-MOF-74 still exhibits a chemical shift anisotropy (CSA) powder pattern. However, there is a certain …

Spin Alignment Generated In Inelastic Nuclear Reactions, Daniel Hoff

Arts & Sciences Graduate Student Theses and Dissertations

The spin alignment of inelastically excited 7Li projectiles, when the target remains in its ground state, was determined through angular-correlation measurements between the breakup fragments of 7Li_ (_ + t). It was found that 7Li_ is largely aligned along the beam axis (longitudinal) in this type of inelastic reaction, regardless of the target. This longitudinal alignment is well described by DWBA calculations, which can be explained by an angular-momentum-excitation-energy mismatch condition. These calculations also explain the longitudinal spin alignment of excited nuclei in several other systems, showing the phenomenon is more general. The experiment involving 7Li was performed at the …

Polarizable Force Field Development, And Applications To Conformational Sampling And Free Energy Calculation, Zhi Wang

Arts & Sciences Graduate Student Theses and Dissertations

The parameters of monovalent ions for the AMOEBA force field were revised. High level quantum mechanics results, relative solvation free energies of monovalent ions, lattice energies and lattice constants of salt crystals were used to calibrate the parameters. The revised parameters were validated against the quantum optimized structures and energies of ion-water dimers and ion-water clusters, and against thermodynamic properties of salt solutions at different concentrations measured in experiments, e.g. mean ionic activity coefficients, self-diffusion coefficients of water. In the simulations the sodium ion is found to qualitatively differ from larger cations in aqueous solution. Direct ionic interactions are predominant …

Regium Bonds Between Mn Clusters (M=Cu,Ag,Au And N=2-6) And Nucleophiles Nh3 And Hcn, Wiktor Zierkiewicz, Mariusz Michalczyk, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The most stable geometries of the coinagemetal (or regium) atom (Cu, Ag, Au) clusters Mn for n up to 6 are all planar, and adopt the lowest possible spin multiplicity. Clusters with even numbers of M atoms are thus singlets, while those with odd n are open-shell doublets. Examination of the molecular electrostatic potential (MEP) of each cluster provides strong indications of the most likely site of attack by an approaching nucleophile, generally one of two positions. A nucleophile (NH3 or HCN) most favorably approaches one particular M atom of each cluster, rather than a bond midpoint or face. In …

Hgf-Induced Formation Of The Met–Axl–Elmo2–Dock180 Complex Promotes Rac1 Activation, Receptor Clustering, And Cancer Cell Migration And Invasion, Wenjing Li, Xiahui Xiong, Amro Abdalla, Salvador Alejo, Linyu Zhu, Fei Lu, Hong Sun

Chemistry and Biochemistry Faculty Research

The MET proto-oncogene–encoded receptor tyrosine kinase (MET) and AXL receptor tyrosine kinase (AXL) are independently operating receptor tyrosine kinases (RTKs) that are functionally associated with aggressive and invasive cancer cell growth. However, how MET and AXL regulate the migratory properties of cancer cells remains largely unclear. We report here that the addition of hepatocyte growth factor (HGF), the natural ligand of MET, to serum-starved human glioblastoma cells induces the rapid activation of both MET and AXL and formation of highly polarized MET–AXL clusters on the plasma membrane. HGF also promoted the formation of the MET and AXL protein complexes and …

Molecular Determinants Of Substrate Specificity In Human Insulin-Degrading Enzyme, Lazaros Stefanidis, Nicholas D. Fusco, Samantha E. Cooper, Jilian E. Smith-Carpenter, Benjamin J. Alper

Chemistry & Physics Faculty Publications

Insulin-degrading enzyme (IDE) is a 110 kDa chambered zinc metalloendopeptidase that degrades insulin, amyloid beta, and other intermediate-sized aggregation prone peptides that adopt β-structures. Structural studies of IDE in complex with multiple physiological substrates have suggested a role for hydrophobic and aromatic residues of the IDE active site in substrate binding and catalysis. Here, we examine functional requirements for conserved hydrophobic and aromatic IDE active site residues that are positioned within 4.5 Angstroms of IDE bound insulin B chain and amyloid beta peptides in the reported crystal structures for the respective enzyme-substrate complexes. Charge, size, hydrophobicity, aromaticity, and other functional …

Structure And Thermodynamics Of Polyglutamine Peptides And Amyloid Fibrils Via Metadynamics And Molecular Dynamics Simulations, Riley Workman

Electronic Theses and Dissertations

Aggregation of polyglutamine (polyQ)-rich polypeptides in neurons is a marker for nine neurodegenerative diseases. The molecular process responsible for the formation of polyQ fibrils is not well understood and represents a growing area of study. To enable development of treatments that could interfere with aggregation of polyQ peptides, it is crucial to understand the molecular mechanisms by which polyQ peptides aggregate into fibrils. Many experimental techniques have been employed to probe polyQ aggregation, however, observations from these studies have not lead to a unified understanding of the properties of these systems, instead yielding competing, fragmented theories of polyQ aggregation. This …

Synthesis Of Modified Biginelli Compounds, Michelle Sarah Collins

Student Theses and Dissertations

The Biginelli reaction has been a distinguished reaction for many years. Their products, the Dihydropyrimidones have been shown to contain a vast array of bioactivity especially when they contain other known bioactive functional groups. Here in we discuss different pathways that these DHPM products can be taken down to combine them with other such bioactive functional groups. We explored the addition of alkene and aldehyde groups to the Biginelli compounds in hopes of synthesizing potential drug candidates. We believe the synthesis of the aldehyde group on the DHPM compounds is a gateway to obtaining the hybrid drug activity we so …

3-Hydroxy-2-(4- Methylphenyl)-4h-Chromen-4-One, Clifford W. Padgett, Will E. Lynch, Kirkland Sheriff, Raven Dean, Sarah Zingales

Chemistry: Faculty Publications (1990-2023)

Our work in the area of carbon-monoxide-releasing mol­ecules led to the synthesis and crystallization of new flavone derivatives as inter­mediates. Herein we report the first crystal structure of the title compound, C16H12O3, a hy­droxy-substituted flavone where the 2-phenyl group has been replaced by a p-tolyl group. The introduction of the 3-hy­droxy group allows the formation of inter­molecular O—H...O=C hydrogen bonds, used to build centrosymmetric R22(10) ring motifs in the crystal.

Fourier Transform Spectroscopy Of The C³Δ-X³Δ Transition Of Tio In Support Of Exoplanet Spectroscopy, James N. Hodges, Peter Bernath

Chemistry & Biochemistry Faculty Publications

Recent limitations in the TiO line list used in cross-correlation detection schemes have made the detection and quantification of TiO in exoplanetary atmospheres challenging. The quality of the line list appears to degrade at wavelengths shorter than 630 nm. The C³Δ-X³Δ electronic transition has strong rovibronic bands near 500 nm. In an effort to improve the line list, a spectrum of TiO in a furnace at 1950 K is analyzed, and the assigned lines of the C³Δ-X³Δ transition are fit with the N² Hamiltonian in the molecular spectrum fitting software, _{PGOPHER …}

Enhanced Acidity Of Acetic And Pyruvic Acids On The Surface Of Water, Alexis J. Eugene, Elizabeth A. Pillar, Agustín J. Colussi, Marcelo I. Guzman

Chemistry Faculty Publications

Understanding the acid–base behavior of carboxylic acids on aqueous interfaces is a fundamental issue in nature. Surface processes involving carboxylic acids such as acetic and pyruvic acids play roles in (1) the transport of nutrients through cell membranes, (2) the cycling of metabolites relevant to the origin of life, and (3) the photooxidative processing of biogenic and anthropogenic emissions in aerosols and atmospheric waters. Here, we report that 50% of gaseous acetic acid and pyruvic acid molecules transfer a proton to the surface of water at pH 2.8 and 1.8 units lower than their respective acidity constants pK_{a …}

Design And Synthesis Of Circadian Clock Modulators And The Study Of Lov Domain Protein Lkp2 In Arabidosis Thaliana And Brassica Rapa, Aditi Nagar

Chemistry Theses and Dissertations

Circadian rhythms are self-autonomous endogenous clocks synchronized with the rotation of the Earth. With the Earth’s rotation and revolution on its axis, the internal clock undergoes oscillation in the period of ~24 hour and governs day to day activities in most organisms. In humans, it regulates the day to day physiological activities. Today’s modern lifestyle has an impact on health: shift work, jet lag, and irregular eating habits contribute to the misalignment of the endogenous circadian oscillator, thereby, increasing the risk of many metabolic disorders including diabetes, irregular blood pressure, sleep disorders, obesity, depression, and cancer. The primary goal of …