Chemistry Commons^™

The Van Der Waals Equation As A Cubic, Carl W. David

Chemistry Education Materials

The van der Waals (from his thesis of 1873) equation is a cubic in the molar volume. Since this is the first equation of state studied in chemistry more complicated than the ideal gas equation, it is noteworthy that the solution of this cubic is rarely if ever addressed. When (lowering the temperature) the two imaginary roots coalesce with the real root of the van der Waals equation we have the critical point. At Kelvin temperatures below Tc. the equation has three real roots; we explore obtaining those roots to aid in the Maxwell construction required to obtain the vapor …

The Contribution Of Methionine To The Stability Of The Escherichia Coli Metniq Abc Transporter-Substrate Binding Protein Complex, P. Nguyen, N. Kadaba, J. Y. Lai, Janet G. Yang, D. C. Rees

Chemistry Faculty Publications

Despite the ubiquitous role of ATP-binding cassette (ABC) importers in nutrient uptake, only the Escherichia coli maltose and vitamin B₁₂ ABC transporters have been structurally characterized in multiple conformations relevant to the alternating access transport mechanism. To complement our previous structure determination of the E. coli MetNI methionine importer in the inward facing conformation (Kadaba et al. (2008) Science 321, 250–253), we have explored conditions stabilizing the outward facing conformation. Using two variants, the Walker B E166Q mutation with ATP+EDTA to stabilize MetNI in the ATP-bound conformation and the N229A variant of the binding protein MetQ, shown in …

The Allosteric Regulatory Mechanism Of The Escherichia Coli Metni Methionine Atp Binding Cassette (Abc) Transporter, Janet G. Yang, D. C. Rees

Chemistry Faculty Publications

The MetNI methionine importer of Escherichia coli, an ATP binding cassette (ABC) transporter, uses the energy of ATP binding and hydrolysis to catalyze the high affinity uptake of d- and l-methionine. Early in vivo studies showed that the uptake of external methionine is repressed by the level of the internal methionine pool, a phenomenon termed transinhibition. Our understanding of the MetNI mechanism has thus far been limited to a series of crystal structures in an inward-facing conformation. To understand the molecular mechanism of transinhibition, we studied the kinetics of ATP hydrolysis using detergent-solubilized MetNI. We find that transinhibition is …

Crystal Structure Of [N,N′-Bis­­(4-Methyl­Phen­Yl)-1,2-Di­Phenyl­Ethane-1,2-Di­Imine-Κ2n,N′]Di­Chlorido­Palladium(Ii) Methanol Monosolvate, Ralph Isovitsch, Alfredo Peñaloza, Frank R. Fronczek

Chemistry

The title compound, [PdCl2(C28H24N2)]·CH3OH, was pre­pared from the reaction of PdCl2(DMSO)2 (DMSO is di­methyl sulfoxide) and N,N′-bis­(4-methyl­phen­yl)-1,2-di­phenyl­ethane-1,2-di­imine in methanol. The chelating di­imine core of the title compound deviates slightly from planarity, with an N—C—C—N torsion angle of 5.3 (3)°. Delocalization in the di­imine core is indicated by N—C and C—C bonds that are, respectively, longer and shorter than those found in related nonchelating di­imines. The distorted square-planar coordination environment around the PdII atom is manifested as bond angles that are smaller and larger than 90°, and palladacycle torsion angles of −173.22 (16) and 167.06 (16)°. These deviations …

Electrolyte Pore/Solution Partitioning By Expanded Grand Canonical Ensemble Monte Carlo Simulation, F. Moucka, D. Bratko, A. Luzar

Chemistry Publications

Using a newly developed grand canonical Monte Carlo approach based on fractional exchanges of dissolved ions and water molecules, we studied equilibrium partitioning of both components between laterally extended apolar confinements and surrounding electrolyte solution. Accurate calculations of the Hamiltonian and tensorial pressure components at anisotropic conditions in the pore required the development of a novel algorithm for a self-consistent correction of nonelectrostatic cut-off effects. At pore widths above the kinetic threshold to capillary evaporation, the molality of the salt inside the confinement grows in parallel with that of the bulk phase, but presents a nonuniform width-dependence, being depleted at …

2015 Oklahoma Research Day Full Program, Northeastern State University

Oklahoma Research Day Abstracts

This document contains all abstracts from the 2015 Oklahoma Research Day held at Northeastern State University.

An Investigation Of The Effect Of Mn2+ On The Fth1 Ire-Irp Complex, Eric Thomas Mendenhall

Theses, Dissertations and Capstones

Iron is a widely distributed metal found in almost every physiological system in nature, thus being an essential part of life. Iron homeostasis in the human body must be tightly regulated as iron is both beneficial and harmful to different cellular processes. Ferritin is a protein that has a prominent role in maintaining iron homeostasis via iron sequestration. Additionally, this protein itself is regulated by the Iron Responsive Element (IRE) and its interaction with an apoaconitase protein or the Iron Regulatory Protein (IRP). The binding of the IRP to this IRE, located on the 5’ untranslated stem loop region of …

Glycation Of Lysozyme, Wisam Talib Joudah

Theses, Dissertations and Capstones

For this research project, I propose a method for the analysis of glycated lysozyme using Matrix Associated Laser Desorption / Ionization-Time of Flight Mass spectrometry (MALDI-TOF MS). Glycation or "Maillard reaction" is a non-enzymatic reaction that occurs between amino acid residues, usually primary and secondary amines, of proteins and the carbonyl group of reducing sugars to yield Schiff bases. The glycation mechanism occurs between the carbonyl group of the reducing sugars and a primary amine by nucleophilic addition, resulting in the formation of a Schiff base. The Schiff base can then rearrange into the more stable Amadori product which is …

Investigation Into The Biological Importance And Function Of Proinsulin C-Peptide, Christina L. Newsome

Theses, Dissertations and Capstones

The C-peptide of insulin was thought to be biologically inactive, but recent studies have shown that the C-peptide causes multiple molecular and physiological effects. Evidence has shown that C-peptide binds to a cell surface receptor, probably a G-protein coupled receptor, and that the COOH-terminal pentapeptide is essential for binding and constitutes an active site. For a further understanding of the detailed nature of the physiological effects of C-peptide, the receptor structure needs to be determined. We designed an affinity column using C-peptide to try and gain a better understanding of the biological effects by examining what proteins the affinity column …

Determination Of Total Peroxide Content In Secondary Organic Aerosol Particles, Matthew E. Wise, John Shilling, Ryan Caylor

CUP Faculty Research

Secondary organic aerosol particles (SOA) formed from the oxidation of monoterpenes can impact the Earth’s radiation balance, act as cloud condensation nuclei and negatively affect human health. In the initial Visiting Faculty Program application, we proposed the use of an ultraviolet-visible spectrometer equipped with a liquid waveguide capillary flow cell to determine the extent to which SOA absorb visible light. The inclusion of Concordia University in the Secondary Organic Aerosol From Forest Emissions Experiment (SOAFFEE) laboratory campaign at PNNL necessitated a change in the proposed experiments. An iodometric-spectrophotometric (IS) technique was developed to quantify the total peroxide content in SOA. …

Determination Of The Optical Properties Of Secondary Organic Aerosol Particles, Matthew E. Wise, John Shilling, Felisha Imholt, Ryan Caylor

CUP Faculty Research

The enhanced greenhouse effect is currently considered to be our most important global environmental problem. While the magnitude of radiation absorbed by greenhouse gases is known to a high certainty, the absorption of radiation by atmospheric aerosol particles is not. In the initial Visiting Faculty Program application, we proposed the use of an ultraviolet-visible (UV/Vis) spectrometer equipped with a liquid waveguide capillary flow cell to determine the extent to which secondary organic aerosol particles (SOA) absorb visible light. Early in the research period, the UV/Vis technique was optimized for three solvent systems (methanol, water and 0.1 M hydrochloric acid). Using …

Proxy-Pet Building Blocks As A Design Element For Library Synthesis, Lainey Jo Mallin

Browse all Theses and Dissertations

In exploring radioligands for positron emission tomography (PET) imaging, it is not unusual to synthesize a library of compounds around some targeting scaffold, screen for optimal binding to a relevant diagnostic cellular target, remove some portion of optimized molecule so as to append the requisite reporter group, and then re-evaluate. To this end, the use of "click labeling" in radiochemistry is proving an increasingly attractive means of conjugating a 18F-reporter group, wherein the targeting scaffold bearing a terminal alkyne is allowed to react with a 2-[18F]-fluoroethylazide to forge a linkage as a 1,2,3-triazole substituent. Since the triazole linked prosthetic group …

Salt And Water Uptake In Nanocon!Nement Under Applied Electric Field: An Open Ensemble Monte Carlo Study, F. Moucka, D. Bratko, A. Luzar

Chemistry Publications

Permeation of electrolytes in nanoporous materials underlies many applications in energy and materials technologies. Wetting of apolar nanopores can be enhanced by electric !eld, attracting water and ions from unperturbed electrolyte bath. We study absorption of water and NaCl in the pores by Expanded Ensemble Grand Canonical Monte Carlo simulation, which implements particle insertions and deletions through incremental changes in particles’ coupling with the system. We determine the uptake of water and ions in the pores, and concomitant changes in pore thermodynamics, as functions of !eld strength in the pore and salinity in the external bath. Pressure increase and reduction …

Rapid Scan Electron Paramagnetic Resonance (Epr) And Digital Epr Development, Zhelin Yu

Electronic Theses and Dissertations

Rapid scan electron paramagnetic resonance (EPR) was developed in the Eaton laboratory at the University of Denver. Applications of rapid scan to wider spectra, such as for immobilized nitroxides, spin-labeled proteins, irradiated tooth and fingernail samples were demonstrated in this dissertation. The scan width has been increased from 55 G to 160 G. The signal to noise (S/N) improvement for slowly tumbling spin-labeled protein samples that is provided by rapid scan EPR will be highly advantageous for biophysical studies. With substantial improvement in S/N by rapid scan, the dose estimation for irradiated tooth enamels became more reliable than …

Enantio-Enriched Cpl-Active Helicene–Bipyridine–Rhenium Complexes, Nidal Saleh, Monika Srebro, Thibault Reynaldo, Nicolas Vanthuyne, Loïc Toupet, Victoria Chang, Gilles Muller, J. Gareth-Williams, Christian Roussel, Jochen Autschbach, Jeanne Crassous

Faculty Publications, Chemistry

The incorporation of a rhenium atom within an extended helical π-conjugated bi-pyridine system impacts the chiroptical and photophysical properties of the resulting neutral or cationic complexes, leading to the first examples of rhenium-based phosphors that exhibit circularly polarized luminescence.

Block Design-Based Asynchronous Neighbor Discovery Protocol For Wireless Sensor Networks, Sangil Choi, Wooksik Lee, Teukseob Song, Jong-Hoon Youn

Chemistry Faculty Publications

Neighbor discovery is a significant research topic in wireless sensor networks. After wireless sensor devices are deployed in specific areas, they attempt to determine neighbors within their communication range. This paper proposes a new Block design-based Asynchronous Neighbor Discovery protocol for sensor networks called BAND. We borrow the concept of combinatorial block designs for neighbor discovery. First, we summarize a practical challenge and difficulty of using the original block designs. To address this challenge, we create a new block generation technique for neighbor discovery schedules and provide a mathematical proof of the proposed concept. A key aspect of the proposed …

Computational Estimation Of The Pka's Of Purines And Related Compounds, Kara L. Geremia

Browse all Theses and Dissertations

The acid dissociation value pKa of a compound provides important information regarding the neutral and ionic forms of the compound present under different conditions. However, for many compounds experimental pKa values are not available, and for others the measured values are sometimes uncertain. Consequently, having a computational means for estimating pKa values can be of benefit for biochemical, pharmaceutical, polymer, and many other studies. Purines form a key group of bioactive compounds whose acid/base activities are of considerable interest. The purine class includes such diverse compounds as the nucleic acid bases adenine and guanine, the gout-related compound uric acid, the …

Dynamic Control Of Nanopore Wetting In Water And Saline Solutions Under An Electric Field, D. Vanzo, D. Bratko, A. Luzar

Chemistry Publications

Field-induced nanopore wetting by aqueous solutions, including electrolytes, provides opportunities for a variety of applications. Con!icting porosity requirements have so far precluded direct implementations of a two-way control: the pores have to be su"ciently wide to allow water in#ltration at experimentally relevant voltages but should not exceed the kinetic threshold for spontaneous expulsion in the absence of the #eld. Applicable widths are restricted below a few nanometers. Only a narrow window of #elds and pore geometries can simultaneously satisfy both of the above requirements. Accurate accounts of wetting equilibria and dynamics at nanoscale porosity require molecular level descriptions. Here we …

Ua66 Ogden College Of Science & Engineering Newsletter, Cheryl Stevens, Dean

Ogden College of Science & Engineering Publications

No abstract provided.

Configurationally Stable, Enantioenriched Organometallic Nucleophiles In Stereospecific Pd-Catalyzed Cross-Coupling Reactions: An Alternative Approach To Asymmetric Synthesis, Chao-Yuan Wang, Joseph Derosa, Mark R. Biscoe

Publications and Research

Several research groups have recently developed methods to employ configurationally stable, enantioenriched organometallic nucleophiles in stereospecific Pd-catalyzed cross-coupling reactions. By establishing the absolute configuration of a chiral alkyltin or alkylboron nucleophile prior to its use in cross-coupling reactions, new stereogenic centers may be rapidly and reliably generated with preservation of the known initial stereochemistry. While this area of research is still in its infancy, such stereospecific cross-coupling reactions may emerge as simple, general methods to access diverse, optically active products from common enantioenriched organometallic building blocks. This minireview highlights recent progress towards the development of general, stereospecific Pd-catalyzed crosscoupling reactions …

The Effects Of Clay On Glycerol/Carboxylic Acid Polymerization: Implications Of Mineral Controls In Prebiotic Chemistry, Joseph T. Romero

Geology: Student Scholarship & Creative Works

Proto-enzymatic catalysis on early Earth is an important consideration in prebiotic chemistry research as it leads to the understanding of the emergence of the metabolic reaction networks. Contemporary enzymes are comprised of either organic or inorganic factors scaffolded by globular protein structure whereas we consider hyperbranched polyesters as a possible extant scaffold that is easier assembled than the peptide one. The goals of this project are to consider prebiotically plausible starting materials for such structure formation utilizing a subset of conditions for polymer synthesis involving the presence of mineral surfaces as well as temperature and hydration differential. As likely candidates …

The First Report Of Lewis Acid Reagents In The Intramolecular Rauhut-Currier Reaction, Andrew T. Krasley, William Paul Malachowski

Chemistry Faculty Research and Scholarship

The first report of Lewis acid use in intramolecular Rauhut-Currier reactions is described. Titanium Lewis acids lead to rapid Rauhut-Currier reactions in the case of two classic substrates. More importantly, titanium and tin Lewis acids were the only successful reagent for a more complex substrate, thereby illustrating the potential for Lewis acid reagents to facilitate challenging intramolecular Rauhut-Currier reactions that fail with traditional reagents.

Probing A Complex Dissociation Energy Surface With Experimental And Theoretical Methods, Hannah Elizabeth Bott

Theses, Dissertations and Capstones

Dendrimers are hyperbranched polymers with a tree-like structure that can be tuned for size, shape, and functionality. Dendrimers have exhibited numerous possibilities in chemical and biochemical processes as their use in host-guest systems and controlled gene and drug delivery vehicles. Distinct properties of dendrimers, such as well-defined architecture and high ratio of functional moieties to molecular volume, make these polymers substantially useful for the development of nanomaterials and medicines. It has recently been demonstrated that polypropylene-imine (PPI) dendrimers have specific physical properties that are well suited for many applications. More specifically, the nitrile-terminated dendrimer creates a unique environment that is …

Ua94/6/15 Student / Alumni Personal Papers Wku Dorris Hutchinson, Wku Archives

WKU Archives Collection Inventories

Correspondence and publications created by and about the Dorris Hutchison during her time at Sloan-Kettering Institute.

The Coastal Monitor: Vol. 1, No. 1, John Tanacredi Ph.D.

The Coastal Monitor

The Center for Environmental Research and Coastal Oceans Monitoring (CERCOM) is a scientific coastal research center and field station dedicated to exploring our global coastal environments and near-shore oceans. CERCOM is the field station support facility for all sciences at Molloy College and services the degree programs of Biology, Chemistry, and Environmental Studies, with special attention to a B.S. degree in Earth and Environmental Studies. Located at the West Sayville Boat Basin on the Great South Bay, CERCOM is a 2,500 sq. ft. field station estuarine/ marine science laboratory where environmental monitoring and analysis is conducted 365 days a year.

Theoretical Examination Of Solvent And R Group Dependence In Gold Thiolate Nanoparticle Synthesis, Suzanne M. Neidhart, Brian M. Barngrover, Christine M. Aikens

Faculty Publications

The growth of gold thiolate nanoparticles can be affected by the solvent and the R group on the ligand. In this work, the difference between methanol and benzene solvents as well as the effect of alkyl (methyl) and aromatic (phenyl) thiols on the reaction energies and barrier heights is investigated theoretically. Density functional theory (DFT) calculations using the BP86 functional and a triple ζ polarized basis set show that the overall reaction favors methylthiol over phenylthiol with reaction energies of −0.54 and −0.39 eV in methanol, respectively. At the same level of theory, the methanol solvent is favored over the …

Prediction Of Nonradical Au (0)-Containing Precursors In Nanoparticle Growth Processes, Brian M. Barngrover, Timothy J. Manges, Christine M. Aikens

Faculty Publications

This density functional theory (DFT) investigation examines the formation of nonradical Au(0) species from the reduction of Au(I) species. The Au(I) complexes of interest are AuCl₂^–, AuBr₂^–, AuI₂^–, AuClPH₃, and AuCl(H)SCH₃⁽⁻⁾, which are precursors for gold nanoparticle and cluster formation. Reaction of two of the Au(I) species with a hydride results in ejection of two of the ligands and formation of Au₂ with two ligands still attached. AuX₂^– (where X = Cl, Br, or I) reactions eject two halides and form Au_{2 …}

Evaluation Of The Performance Of A Rural Municipal Wastewater Treatment Plant In Nacogdoches, East Texas (Usa) (Abstract), Kefa Karimu Onchoke, Michael Janusa, Salomey Asantewaa Sasu

Faculty Publications

The performance of a rural wastewater treatment facility, Nacogdoches Wastewater Treatment Plant

(NWWTP), in East Texas, USA, was assessed from January 2013 through June 2014. The elemental concentrations (Na, Mg, Ca, Ni, Pb, Mn, Cr, Mo, and Cu, Al, As, B, Ba, Ag, Cd, Fe, Hg, K, Se, Zn, Co, P, and S) were measured using inductively coupled plasma optical emission spectrometry. The anion concentrations (Br−, NO3- , NO2- , PO34-,F−, Cl−, and SO24−) were measured by ion chromatography. In general, the NWWTP was found efficient in removal to ≥ 96% for metals. The removal efficiency for anions was in …

Measurement Of Particulate Transition Metals And Atmospheric Processing Of Iron, Benton T. Cartledge

Electronic Theses and Dissertations

The work presented herein details the measurement of particle-bound metals in environmental samples with specific interests in iron (Fe) in atmospheric particulate matter. Metals were measured in ambient PM_2.5 to study the effects and contributions of a light rail system on the concentrations of metals in atmospheric particles. Particulate matter samples were collected on board trains, near the tracks, and at an urban background location in Denver, CO. Metals were found to be enriched in particles collected on board the trains more so than at the other locations. Fe speciation was also measured in the soluble fraction of the …

Multiple-Choice Testing Using Immediate Feedback-Assessment Technique (If At®) Forms: Second-Chance Guessing Vs. Second-Chance Learning?, Jeremy D. Merrel, Pier F. Cirillo, Pauline M. Schwartz, Jeffrey Webb

Chemistry and Chemical Engineering Faculty Publications

Multiple choice testing is a common but often ineffective method for evaluating learning. A newer approach, however, using Immediate Feedback Assessment Technique (IF AT®, Epstein Educational Enterprise, Inc.) forms, offers several advantages. In particular, a student learns immediately if his or her answer is correct and, in the case of an incorrect answer, has an opportunity to provide a second response and receive partial credit for a correct second attempt. For a multiple choice question with five possible answers, the IF AT® form covers spaces labeled A through E with a thin opaque film; when the film is scratched away, …