Chemistry Commons^™

Imaging Of Neurotransmitters And Small Molecules In Brain Tissues Using Laser Desorption/Ionization Mass Spectrometry Assisted With Zinc Oxide Nanoparticles., Chaochao Chen, Steven R Laviolette, Shawn N Whitehead, Justin B Renaud, Ken K-C Yeung

Chemistry Publications

Inorganic nanostructured materials such as silicon, carbon, metals, and metal oxides have been explored as matrices of low-background signals to assist the laser desorption/ionization (LDI) mass spectrometric (MS) analysis of small molecules, but their applications for imaging of small molecules in biological tissues remain limited in the literature. Titanium dioxide is one of the known nanoparticles (NP) that can effectively assist LDI MS imaging of low molecular weight molecules (LMWM). TiO₂ NP is commercially available as dispersions, which can be applied using a chemical solution sprayer. However, aggregation of NP can occur in the dispersions and the aggregated NP …

Multi-Institutional Study Of Self-Efficacy Within Flipped Chemistry Courses, Nicole Naibert, Kerry D. Duck, Michael M. Phillips, Jack Barbera

Chemistry Faculty Publications and Presentations

Active learning environments have been shown to be beneficial for student learning; however, including such activities can be limited by the class time available. One method that can provide more opportunities for active learning during face-to-face class time is the flipped learning approach. However, studies on the impacts of flipped learning environments on student motivation are limited. Therefore, in this multi-institutional study, general chemistry students enrolled in flipped courses at three institutions responded to measures of self-efficacy and self-regulatory strategies. The results from these measures were used to evaluate how students’ academic self-efficacy (ASE) and chemistry self-efficacy (CSE) changed over …

Adsorption And Transport Of Colloids At Interface And In Bulk, Jingyun Lee

LSU Doctoral Dissertations

Colloids are suspensions of microscopic insoluble particles dispersed in a continuum phase such as liquid or gas. Colloids are found in our everyday life from food and cosmetic industries to pharmaceutical and biomedical applications. Depending on a global minimum of the free-energy landscape, colloidal suspensions can be classified as two major classes: equilibrium or active colloidal system. This Ph.D dissertation presents strategies to engineer equilibrium self-assembled structures and out-of-equilibrium active matter using various interparticle forces.

First, we introduce the means to promote the equilibrium self-assembled structures driven by adsorption of colloids at interface. Typically, adsorption of colloids at interface is …

Optimizing Fluorescence Pmt Gain And Excitation Wavelength For Hplc Dl-Amino Acid Detection, Daranthea Amanda Atmadja, Aaron Jacobs

Honors Scholars & Undergraduate Research Poster Symposium Programs

Amino acids exist as enantiomers that can be separated and detected using HPLC-FLD. An optimal PMT gain and wavelength of excitation must be determined to lower the limit of detection (LOD) and quantitation (LOQ) as increasing the PMT gain amplifies the signal on the HPLC-Spectra. The HPLC-FLD spectra of OPA-IBLC derivatized histidine was measured at PMT gain 5 and 7 for the excitation wavelengths of 340-, 260-, and 240- nm. Hence, the optimal excitation wavelength and PMT gain can be determined by comparing the fluorescence spectra.

Past, Present, And Future– A Review Of Berrien County Water And Great Lakes Water Resources And Quality, Jongwan Bae

Honors Scholars & Undergraduate Research Poster Symposium Programs

The decrease in water quality for environmental and drinking water has been prevalent in the Great Lakes region, where industrialization, agricultural development, and population increase have contributed substantially. Looking through historical reports and the present, the degradation in water quality will likely continue. Our research intends to use inductively coupled plasma atomic emission spectroscopy to create a methodology to quantitatively detect various heavy metals and other elements from any water source. Current research has been on the determination of a niche in water testing and the creation of an infographic, as well as data of simple water samples.

Copper (Ii) Sequestration By Pamam Dendrimers In Tap Water, Hannah Castillo

Honors Scholars & Undergraduate Research Poster Symposium Programs

Dendrimers are nanomaterials that are widely studied for a variety of applications because of their distinctive properties. One such property of, specifically, the generation 2-PAMAM Dendrimer is its particular affinity for copper (II) ions. This could be influential in selective heavy metal extraction, particularly in contaminated water. Our research aims to test the sequestration and selectivity of PAMAM dendrimers with amine surface groups for copper (II) ions in a chemical environment with interfering species, such as tap water, using Inductively Coupled Plasma spectroscopy. Ongoing research has involved developing methods for dendrimer extractions and creating calibration curves for standards to ensure …

Determination Of Atrazine In Glacier Creek Using Gas Chromatography-Mass Spectrometry, Spencer Witte

UNO Student Research and Creative Activity Fair

Atrazine is a commonly used herbicide in agriculture that has been shown to cause adverse health-effects on biological organisms. Glacier Creek Preserve (GCP), a prairie preserve near Omaha, NE, contains restored prairie and agricultural land uses within a single watershed. Surface water samples were collected at various locations of GCP from May to July to quantify atrazine concentrations. Sample preparation included filtering with a 0.45 micron filter and solid-phase extraction (SPE) with a reversed-phase cartridge. The analyte was eluted off the cartridge with ethyl acetate and analyzed by gas chromatography-mass spectrometry (GC/MS). Quantitation was performed with an internal standard calibration …

Data For "Subtype-Selective Positive Modulation Of Sk Channels Depends On The Ha/Hb Helices", Miao Zhang, Meng Cui

Pharmacy Faculty Data Sets

In the activated state of small-conductance Ca²⁺-activated potassium (SK) channels, calmodulin interacts with the HA/HB helices and the S4-S5 linker. CyPPA potentiates SK2a and SK3 channel activity but not the SK1 and IK subtypes. Here, we report that the subtype-selectivity of CyPPA relies on the HA/HB helices. Mutating residues in the HA (V420) and HB (K467) helices of SK2a channels to their equivalent residues in IK channels diminished the potency of CyPPA. CyPPA elicited prominent responses on mutant IK channels with an arginine residue in the HB helix substituted for its equivalent lysine residue in the SK2a channels …

Molecular Design Of Three-Dimensional Metal-Free A(Nh4)X3 Perovskites For Photovoltaic Applications, Jie Bie, Dai-Bei Yang, Ming-Gang Ju, Qiang Pan, Yu-Meng You, Wei Fa, Xiao Cheng Zeng, Shuang Chen

Xiao Cheng Zeng Publications

The intense research activities on the hybrid organic−inorganic perovskites (HOIPs) have led to the greatly improved light absorbers for solar cells with high power conversion efficiency (PCE). However, it is still challenging to find an alternative lead-free perovskite to replace the organohalide lead perovskites to achieve high PCE. This is because both previous experimental and theoretical investigations have shown that the Pb²⁺ cations play a dominating role in contributing the desirable frontier electronic bands of the HOIPs for light absorbing. Recent advances in the chemical synthesis of three-dimensional (3D) metal-free perovskites, by replacing Pb²⁺ with NH₄^{+ …}

Pressure- And Temperature-Dependent Inelastic Neutron Scattering Study Of The Phase Transition And Phonon Lattice Dynamics In Para-Terphenyl, Qingan Cai, Michael Mcintire, Luke L. Daemen, Chen Li, Eric Chronister

Chemistry and Biochemistry Faculty Research

Inelastic neutron scattering has been performed on para-terphenyl at temperatures from 10 to 200 K and under pressures from the ambient pressure to 1.51 kbar. The temperature dependence of phonons, especially low-frequency librational bands, indicates strong anharmonic phonon dynamics. The pressure- and temperature-dependence of the phonon modes suggest a lack of phase transition in the region of 0-1.51 kbar and 10-30 K. Additionally, the overall lattice dynamics remains similar up to 200 K under the ambient pressure. The results suggest that the boundary between the ordered triclinic phase and the third solid phase, reported at lower temperatures and higher pressures, …

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

Chemistry Faculty Patents

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

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

Steep Sulfur Gradient In Cztsse Solar Cells By H2s-Assisted Rapid Surface Sulfurization, Teoman Taskesen, Devendra Pareek, Dirk Hauschild, Alan Haertel, Lothar Weinhardt, Wanli Yang, Timo Pfeiffelmann, David Nowak, Clemens Heske, Levent Gütay

Chemistry and Biochemistry Faculty Research

Sulfur/selenium grading is a widely used optimization strategy in kesterite thin-film solar cells to obtain a bandgap-graded absorber material and to optimize optical and electrical properties of the solar-cell device. In this work, we present a novel approach to introduce a [S]/([S] + [Se]) grading for Cu ZnSn(S,Se) solar cells. In contrast to commonly used methods with slow process dynamics, the presented approach aims to create a fast sulfurization reaction on the surface of pure selenide kesterite absorbers by using highly reactive H S gas and high sulfurization temperatures in a rapid flash-type process. With a combination of X-ray photoelectron …

Noncovalent Bonds Through Sigma And Pi-Hole Located On The Same Molecule. Guiding Principles And Comparisons, Wiktor Ziekiewicz, Mariusz Michalczyk, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Over the last years, scientific interest in noncovalent interactions based on the presence of electron-depleted regions called σ-holes or π-holes has markedly accelerated. Their high directionality and strength, comparable to hydrogen bonds, has been documented in many fields of modern chemistry. The current review gathers and digests recent results concerning these bonds, with a focus on those systems where both σ and π-holes are present on the same molecule. The underlying principles guiding the bonding in both sorts of interactions are discussed, and the trends that emerge from recent work offer a guide as to how one might design systems …

Telsam-Target Protein Fusions Can Form Diffraction-Quality Crystals Without Direct Inter-Polymer Contacts, Moriah Longhurst

Undergraduate Honors Theses

X-ray diffraction is a robust method for determining the detailed 3D structures of specific proteins. However, this requires the formation of well-ordered protein crystals, a process that is time-consuming, expensive, and only has about a 10-30% success rate. New methods are needed to enable the efficient crystallization of challenging proteins. One such technique is explored here, which utilizes a protein polymer (the sterile alpha motif domain of the human protein translocation Ets leukemia, or TELSAM) as a crystallization chaperone to form a more ordered crystal lattice of target proteins and drive crystallization. This method was successfully used to crystallize, collect …

The Zinc-Binding Domain Of Mammalian Prolyl-Trna Synthetase Is Indispensable For Catalytic Activity And Organism Viability, Kommireddy Vasu, Iyappan Ramachandiran, Fulvia Terenzi, Debjit Khan, Arnab China, Krishnendu Khan, Aayushi Chechi, Camelia Baleanu-Gogonea, Valentin Gogonea, Paul L. Fox

Chemistry Faculty Publications

Aminoacyl-tRNA synthetases (AARS) participate in decoding the genome by catalyzing conjugation of amino acids to their cognate tRNAs. During evolution, biochemical and environmental conditions markedly influenced the sequence and structure of the 20 AARSs, revealing adaptations dictating canonical and orthogonal activities. Here, we investigate the function of the appended Zn2+-binding domain (ZBD) in the bifunctional AARS, glutamyl-prolyl-tRNA synthetase (GluProRS). We developed GluProRS mutant mice by CRISPR-Cas9 with a deletion of 29 C-terminal amino acids, including two of four Zn2+-coordinating cysteines. Homozygous ZBD mutant mice die before embryonic day 12.5, but heterozygous mice are healthy. ZBD disruption profoundly reduces GluProRS canonical …

Alternative View Of Oxygen Reduction On Porous Carbon Electrocatalysts: The Substance Of Complex Oxygen-Surface Interactions, Giacomo De Falco, Marc Florent, Jacek Jagiello, Yongqiang Cheng, Luke L. Daemen, Anibal J. Ramirez-Cuesta, Teresa J. Bandosz

Publications and Research

Electrochemical oxygen reduction reaction (ORR) is an important energy-related process requiring alternative catalysts to expensive platinum-based ones. Although recently some advancements in carbon catalysts have been reported, there is still a lack of understanding which surface features might enhance their efficiency for ORR. Through a detailed study of oxygen adsorption on carbon molecular sieves and using inelastic neutron scattering, we demonstrated here that the extent of oxygen adsorption/interactions with surface is an important parameter affecting ORR. It was found that both the strength of O2 physical adsorption in small pores and its specific interactions with surface ether functionalities in the …

Improving Sers Detection Of Illicit Drugs Using A Plasmonic Substrate Modified With Self-Assembled Monolayers, John Harms

Theses and Dissertations

Due to the worsening national drug epidemic and increasing prevalence of exceptionally potent synthetic opioids, there is a need to improve the forensic detection of illicit drugs, including sample analyses conducted on-site. In this thesis, the analysis of several illicit drugs spotted onto plasmonic surfaces was investigated using surface-enhanced Raman spectroscopy (SERS) with the goal of improving detection limits. Plasmonic surfaces (gold nanoparticle-loaded filter papers) were prepared and characterized prior to their SERS applications. Plasmonic surfaces were then further modified for improved SERS detection of each illicit drug with the treatment of self-assembled monolayer (SAM) forming compounds; in addition to …

A Systematic Multiscale Investigation Of Nanoparticle-Assisted Co2 Enhanced Oil Recovery (Eor) Process For Shale Oil Reservoirs, Dayo A. Afekare

LSU Doctoral Dissertations

Shale oil reservoirs are prolific on the short term due to hydraulic fracturing and horizontal drilling but experience significant production decline, leading to poor ultimate recovery and leaving billions of barrels of oil buried in the ground. In this study, a systematic multi-scale investigation of an enhanced oil recovery (EOR) process using relatively inexpensive silicon dioxide nanoparticles and carbon dioxide for shale oil reservoirs was conducted. Using the Tuscaloosa Marine Shale (TMS) as a case study, aqueous dispersions of nanosilica in conjunction with CO₂ were investigated at nano-to-core scales. At the nanoscale, atomic force microscope was used to investigate …

Investigations Of The Structure And Protein-Protein Interactions Of Chlamydia Trachomatis Scc4, Thilini Oshadhi Senarath Ukwaththage

LSU Doctoral Dissertations

Chlamydia trachomatis (CT) is the most common, sexually transmitted bacterial disease (STD) in the world. In the developmental cycle of CT, specific chlamydia chaperone 4 (Scc4) is a unique protein with essential and multiple roles. Hence, Scc4 is significant as a virulence target for therapeutic approaches to treat chlamydial infections. A novel approach was discovered to purify tag free Scc4 by utilizing a 6X-histidine-tag on Scc1 in the co-expressed Scc4:Scc1 complex by capturing the complex on nickel-charged immobilized metal affinity chromatography resin, followed by dissociation of Scc4 with sarkosyl. Using triple resonance NMR experiments, backbone and sidechain resonances …

Novel Synthetic Transformations Targeting Δ-Valerolactone And Isocoumarin, Joshua Paul Van Houten

LSU Doctoral Dissertations

The purpose of this dissertation is to describe the efforts undertaken to develop synthetic methodology targeting δ-valerolactone and isocoumarin. At the onset, an introduction to the δ-valerolactone and isocoumarin is given. Relevant examples of δ-valerolactone being utilized in the production of materials of biological and industrial application are then discussed. Following, current methods for forming δ-valerolactone are presented. After, an introduction to isocoumarin is begun. Current methods for producing isocoumarin are then discussed.

The results and discussion section of this dissertation will focus on two methods that were explored with the goal of producing α-acyl-δ-valerolactone with two different substitution patterns. …

Designing Ionic Liquid-Derived Polymer Composites From Poly(Ionic Liquid)–Ionene Semi-Interpenetrating Networks, Kathryn E. O'Harra, George E. Timmerman, Jason E. Barra, Kevin Miller

Faculty & Staff Research and Creative Activity

While the solvating power of ionic liquids (ILs) for a variety of solute types including polymers is well-known, the use of ILs as solvents for ionenes—charged polymers with cationic moieties within the backbone—has only recently begun to be explored. IL–ionene combinations offer vast possibilities to make iongels and perhaps even use ILs to exert control over ionene organization (i.e., coil or rod). If the IL solvent is also polymerizable, then poly(IL)–ionene semi-interpenetrating networks (semi-IPNs) can be achieved. This study reports, for the first time, examples of poly(IL)–ionene semi-IPNs formed by dissolving an ionene in a vinyl-functionalized imidazolium IL followed by …

Influence Of Counteranion And Humidity On The Thermal, Mechanical And Conductive Properties Of Covalently Crosslinked Ionenes, Nicholas C. Bontrager, Samantha Radomski, Samantha P. Daymon, R. Daniel Johnson, Kevin M. Miller

Faculty & Staff Research and Creative Activity

Thiol-ene photopolymerization was used to generate a series of covalently crosslinked, imidazolium-containing ionene networks. A variety of counteranions were chosen so as to investigate the influence of size and basicity on the thermal, mechanical and conductive properties of the resulting networks. Anhydrous conductivities at 20 °C were found to be on the order of 10−6 to 10−10 S/cm and correlated to some degree with Tg; however, Tg-normalization of the curves indicated that this relationship between polymer structure and conductivity was more complex. VFT fitting, along with free ion concentration and ion mobility data, were investigated in order to …

Advances In Ultra-High-Pressure And Multi-Dimensional Liquid Chromatography Instrumentation And Workflows, Jelle De Vos, Dwight Stoll, Stephan Buckenmaier, Sebastiaan Eeltink, James P. Grinias

College of Science & Mathematics Departmental Research

The present contribution discusses recent advances in ultra-high-pressure liquid chromatography (UHPLC) and multi-dimensional liquid chromatography (MDLC) technology. First, new developments in UHPLC column technology and system design are highlighted. The latter includes a description of a novel injector concept enabling method speed-up, emerging detectors, and instrument diagnostics approaches. Next, online MDLC workflows are reviewed and advances in modulation technology are highlighted. Finally, key applications published in 2020 are reviewed.

Synthesis Of Oxyquinoliziniporphyrins And Pyridoquinoliziniporphyrins, Emma Cramer

Theses and Dissertations

N-confused porphyrins are porphyrin analogues that introduce a nitrogen outside of the macrocyclic cavity. Two novel N-confused type porphyrins were targeted for this study. Both syntheses use the key intermediate 4-quinolizone. Previous studies of N-confused pyriporphyrin showed that the system is nonaromatic and resembles structurally analogous benziporphyrins. However, modifications to systems of this type can introduce aromatic characteristics. The first system targeted introduced a quinolizone subunit into a porphyrin system. Quinolizone contains a thermodynamically stable amide and this unit disrupts the aromatic pathway. However, dipolar resonance contributors can potentially reinstate some aromatic character. A quinolizone dialdehyde was condensed with tripyrranes …

Atomic-Resolution 1.3 Å Crystal Structure, Inhibition By Sulfate, And Molecular Dynamics Of The Bacterial Enzyme Dape, Matthew Kochert, Boguslaw P. Nocek, Thahani S. Habeeb Mohammad, Elliot Gild, Kaitlyn Lovato, Tahirah K. Heath, Richard C. Holz, Kenneth W. Olsen, Daniel P. Becker Ph.D.

Chemistry: Faculty Publications and Other Works

We report the atomic-resolution (1.3 Å) X-ray crystal structure of an open conformation of the dapE-encoded N-succinyl-l,l-diaminopimelic acid desuccinylase (DapE, EC 3.5.1.18) from Neisseria meningitidis. This structure [Protein Data Bank (PDB) entry 5UEJ] contains two bound sulfate ions in the active site that mimic the binding of the terminal carboxylates of the N-succinyl-l,l-diaminopimelic acid (l,l-SDAP) substrate. We demonstrated inhibition of DapE by sulfate (IC50 = 13.8 ± 2.8 mM). Comparison with other DapE structures in the PDB demonstrates the flexibility of the interdomain connections of this protein. This high-resolution structure was then utilized as the …

Indolizine Donor-Based Dyes For Applications In Fluorescence Biological Imaging, William Meador

Honors Theses

NIR emissive fluorophores are intensely researched due to their potential to replace modern imaging procedures. Many molecular strategies have been employed in the literature to optimize fluorophores for deeper NIR absorption and emission, biocompatibility, and higher fluorescence quantum yields. Amongst the fluorophores studied to date, proaromatic indolizine donors are attractive alternatives to traditional alkyl amine and indoline based donors due to their 1) lower energy absorption and emission facilitated by proaromaticity, 2) large Stokes shifts due to increased dihedral angles about the π-system, 3) ease of functionalization and capacity for bioconjugation at the phenyl ring, and 4) potential for further …

Three-Way Analysis-Based Ph-Uv-Vis Spectroscopy For Quantifying Allura Red In An Energy Drink And Determining Colorant's Pka, Erdal Dinç Prof., Nazangül Ünal, Zehra Ceren Ertekin

Journal of Food and Drug Analysis

Three-way analysis-based pH-UV-Vis spectroscopy was proposed for quantifying allura red in an energy drink product without the need for chromatographic analysis, and determining the colorant’s pKa without using any titration technique. In this study, UV-Vis spectroscopic data matrices were obtained from absorbance measurements at five different pH levels from pH 8 to pH 12 and arranged as a three-way array (wavelength x sample x pH). In the three-way analysis procedure, parallel factor analysis (PARAFAC) was implemented to decompose the three-way array into a set of trilinear components. Each set of three components relates to spectral, pH and relative concentration profiles …

Representing Methane Emissions From Wet Tropical Forest Soils Using Microbial Functional Groups Constrained By Soil Diffusivity, Debjani Sihi, Xiaofeng Xu, Mónica Salazar Ortiz, Christine S. O'Connell, Whendee L. Silver, Carla López-Lloreda, Julia M. Brenner, Ryan K. Quinn, Jana R. Phillips, Brent D. Newman, Melanie A. Mayes

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Tropical ecosystems contribute significantly to global emissions of methane (CH₄), and landscape topography influences the rate of CH₄ emissions from wet tropical forest soils. However, extreme events such as drought can alter normal topographic patterns of emissions. Here we explain the dynamics of CH₄ emissions during normal and drought conditions across a catena in the Luquillo Experimental Forest, Puerto Rico. Valley soils served as the major source of CH₄ emissions in a normal precipitation year (2016), but drought recovery in 2015 resulted in dramatic pulses in CH₄ emissions from all topographic positions. Geochemical parameters …

Novel Phenolic Deep Eutectic Solvents For Desulfurisation Of Petrodiesel, Idrees Bakr Qader, Jalil H. Kareem, Hani K. Ismail, Hawbash K. Mahmood

Karbala International Journal of Modern Science

In this work, a novel production of “deep eutectic solvents (DESs)” has been utilised for the elimination of sulfur composition, particularly from crude oil by liquid-liquid extraction. Herein, we present the first demonstration of the use of novel DESs formed by phenol, catechol, resorcinol and o-cresol as “hydrogen bond donors (HBDs)” with trimethyl hydroxyammonium chloride (ChCl) as the hydrogen bond acceptor to affect the efficient separation of organosulfur compounds from diesel. These DES electrolytes have been applied for the sulfur extraction from Iraqi real diesel fuel as determined using X-ray florescence sulfur measurements. The optimisation condition factors in this research …

Anticancer And Antiangiogenic Activities Of Alkaloids Isolated From Lantana Camara By Adsorption On The Magnetic Nanoparticles, Hussein Kadhem Al-Hakeim, Rahman Sahib Al-Zabibah, Huda Falah Alzihari, Ali Khudhair Almensoori, Hazim A. Al-Zubaidi, Loiy Elsir Ahmed Hassan Hassan

Karbala International Journal of Modern Science

Lantana camara L. (L. camara) is a perennial shrub that contains low amounts of alkaloids. In the present study, the magnetic nanoparticles (MNPs) were used to isolate positively charged alkaloids from the methanolic extract of L. camara leaves. The crude alkaloid was fractionated using HPLC to separate the highest peak of the alkaloid fraction (HPAF). The crude alkaloids (CA) and HPAF were tested for their antiproliferative effect against cancer cell lines (MCF-7, HCT-116, and HeLa) and endothelial cells line (EA.hy926) as a standard cell line. Antiangiogenic properties were examined using rat aortic ring assay. …