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Chemistry Faculty Publications

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Articles 241 - 270 of 1129

Full-Text Articles in Chemistry

Detection And Characterization Of The Tin Dihydride (Snh2 And Snd2) Molecule In The Gas Phase, Tony C. Smith, Dennis J. Clouthier Jan 2018

Detection And Characterization Of The Tin Dihydride (Snh2 And Snd2) Molecule In The Gas Phase, Tony C. Smith, Dennis J. Clouthier

Chemistry Faculty Publications

The SnH2 and SnD2 molecules have been detected for the first time in the gas phase by laser-induced fluorescence (LIF) and emission spectroscopic techniques through the Ã1B1–X̃1A1 electronic transition. These reactive species were prepared in a pulsed electric discharge jet using (CH3)4Sn or SnH4/SnD4 precursors diluted in high pressure argon. Transitions to the electronic excited state of the jet-cooled molecules were probed with LIF, and the ground state energy levels were measured from single rovibronic level emission spectra. The LIF spectrum of SnD2 …

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Palladium-Catalyzed Carbonyl Allylation Reactions Using Tin Chloride: A Mini-Review, Armando M. Guidote Jr, Mikael John A. Baltazar, Roy Kristian C. Yanela, Noriyuki Suzuki Jan 2018

Palladium-Catalyzed Carbonyl Allylation Reactions Using Tin Chloride: A Mini-Review, Armando M. Guidote Jr, Mikael John A. Baltazar, Roy Kristian C. Yanela, Noriyuki Suzuki

Chemistry Faculty Publications

The treatment of allylic alcohols as synthons of carbanions for carbonyl allylation reactions in the presence of a Pd-SnCl2 system has been one of the most interesting and most useful developments demonstrated by Yoshiro Masuyama and co-workers in the field of organic synthesis. The reaction makes use of palladium as an effective catalyst and tin (II) chloride as a low-valent reducing agent which also effectively transforms the allylic group to a nucleophilic group. The organic, as well as organometallic, chemistry of how the transformations occur and how the metals take part in the reaction is of great interest. These could …

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Crystallographically Defined Silicon Macropore Membranes, Shannon C. Knight, Bret A. Unger, Kurt W. Kolasinski Jan 2018

Crystallographically Defined Silicon Macropore Membranes, Shannon C. Knight, Bret A. Unger, Kurt W. Kolasinski

Chemistry Faculty Publications

Laser ablation with nanosecond-pulsed Nd:YAG laser irradiation combined with anisotropic alkaline etching of Si wafers creates 4–20 µm macropores that extend all the way through the wafer. The walls of these macropores are crystallographically defined by the interaction of the anisotropy of the etchant with the orientation of the single-crystal silicon substrate: rectangular/octagonal on Si(001), parallelepiped on Si(110), triangular/hexagonal on Si(111). Laser ablation can create pillars with peak-tovalley heights of over 100 µm. However, with nanosecondpulsed irradiation at 532 nm, the majority of this height is created by growth above the original plane of the substrate whereas for 355 nm …

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Plume And Nanoparticle Formation During Laser Ablation, Kurt W. Kolasinski, Mool C. Gupta, Leonid V. Zhigilei Jan 2018

Plume And Nanoparticle Formation During Laser Ablation, Kurt W. Kolasinski, Mool C. Gupta, Leonid V. Zhigilei

Chemistry Faculty Publications

The processes that lead to material ejection when a solid sample is irradiated near and above the pulsed laser ablation threshold are discussed. Emphasis is placed on the thermal and mechanical mechanisms that occur during pulsed laser irradiation of metals and semiconductors. Distinctions are drawn between ultrafast-pulsed irradiation, which occurs under stress confinement, and shortpulsed irradiation, in which stress is released during the laser pulse. Similarly, the distinctions between the spallation and phase explosion regimes are discussed. Spallation is only possible when the time of the laser heating is shorter than the time needed for mechanical equilibration of the heated …

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Hierarchical Porous Silicon And Porous Silicon Nanowires Produced With Regenerative Electroless Etching (Reetching) And Metal Assisted Catalytic Etching (Mace), Kurt W. Kolasinski, Bret A. Unger, Haibo Yu, Alexis T. Ernst, Mark Aindow, Ermei Mäkilä, Jarno Salonen Jan 2018

Hierarchical Porous Silicon And Porous Silicon Nanowires Produced With Regenerative Electroless Etching (Reetching) And Metal Assisted Catalytic Etching (Mace), Kurt W. Kolasinski, Bret A. Unger, Haibo Yu, Alexis T. Ernst, Mark Aindow, Ermei Mäkilä, Jarno Salonen

Chemistry Faculty Publications

ReEtching produces nanostructured silicon when a catalytic agent, e.g. dissolved V2O5, is used to facilitate etching between Si and H2O2. H2O2 regenerates dissolved V in a 5+ oxidation state, which initiates etching by injecting holes into the Si valence band. Independent control over the extent of reaction (controlled by the amount of H2O2 added) and the rate of reaction (controlled by the rate at which H2O2 is pumped into the etchant solution) allows us to porosify Si substrates of arbitrary size, shape and doping, including wafers, single-crystal powders, polycrystalline powders, metallurgical grade powder, Si nanowires, Si pillars and Si powders …

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Silicon Surface Photochemistry, Kurt W. Kolasinski Jan 2018

Silicon Surface Photochemistry, Kurt W. Kolasinski

Chemistry Faculty Publications

General concepts of photochemistry on metal and semiconductor surfaces are elucidated. These concepts are then applied more specifically to describe photochemical transformation of molecules on and with silicon surfaces. The mechanisms by which light can induce chemical reactions following electronic excitation are described. Processes reviewed include photodissociation of adsorbed molecules, photo-induced attachment of organic molecules and photo-induced corrosion.

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Structural Identification And Kinetic Analysis Of The In Vitro Products Formed By Reaction Of Bisphenol A‑3,4-Quinone With N‑Acetylcysteine And Glutathione, Douglas E. Stack, John A. Conrad, Bejan Mahmud Jan 2018

Structural Identification And Kinetic Analysis Of The In Vitro Products Formed By Reaction Of Bisphenol A‑3,4-Quinone With N‑Acetylcysteine And Glutathione, Douglas E. Stack, John A. Conrad, Bejan Mahmud

Chemistry Faculty Publications

Bisphenol A (BPA) has received considerable attention as an endocrine disrupting chemical and a possible substrate for genotoxic metabolites. BPA metabolism leads to formation of electrophilic o-quinones cable of binding to DNA and other endogenous nucleophiles. We have structurally identified the products resulting from the reaction of bisphenol A-3,4-quinone (BPAQ) with N-acetylcysteine (NAC) and glutathione (GSH). The major and minor isomers are both the result of 1,6-conjugate addition and are produced almost instantly in high yield. Reactions using 1.3 equiv of GSH showed the presence of a bis-glutathionyl adduct which was not observed using higher GSH concentration relative to BPAQ. …

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Prediction Of Novel Anti-Ebola Virus Compounds Utilizing Artificial Neural Network (Ann), Ronald Bartzatt Jan 2018

Prediction Of Novel Anti-Ebola Virus Compounds Utilizing Artificial Neural Network (Ann), Ronald Bartzatt

Chemistry Faculty Publications

Artificial Neural Network (ANN) analysis is shown to predict the molecular properties of new anti-EBOLA compounds following training/learning by use of 60 previously known and studied drugs. Following training/learning by applying properties of 60 known drugs the TIBERIUS ANN system can efficiently predict the molecular properties of comparable new drugs. Molecular weight (MW) is an important and dominant property of perspective drugs considered for clinical trials. TIBERIUS ANN was able to predict comparable values of MW for drugs following training cycles. One-way ANOVA, F and T tests indicate that actual and predicted MW have the same means (P=.99). Passing-Bablok regression …

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One-Pot Enol Silane Formation-Alkylation Of Ketones With Propargyl Carboxylates Promoted By Trimethylsilyl Trifluoromethanesulfonate, C. Wade Downey, Danielle N. Confair, Yiqi Liu, Elizabeth D. Heafner Jan 2018

One-Pot Enol Silane Formation-Alkylation Of Ketones With Propargyl Carboxylates Promoted By Trimethylsilyl Trifluoromethanesulfonate, C. Wade Downey, Danielle N. Confair, Yiqi Liu, Elizabeth D. Heafner

Chemistry Faculty Publications

Ketones readily undergo conversion to enol silanes in the presence of trialkylamine base and trimethylsilyl trifluoromethanesulfonate (TMSOTf) and add to propargyl cations to yield b-alkynyl ketones. The propargyl cations are generated in the same reaction flask through the TMSOTf-promoted ionization of propargyl acetates or propargyl propionates. A range of enol silane precursors and propargyl carboxylates reacts efficiently (20 examples, up to 99% yield). Cyclization of a representative product in the presence of TMSOTf provided 61% yield of the trisubstituted furan.

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Theoretical Circular Dichroism Spectra Of The Α-Helical Protein Calexitin With The Dipole Interaction Model Including The N-Π* Transition, Akongnwi C. Jungong, Tsvetan Aleksandrov, Rahul Nori, Justin Erickson, Kathryn A. Thomasson, Igor V. Uporov, Ethan R. Austhof, Emily Holt, Felix N. Ngassa Jan 2018

Theoretical Circular Dichroism Spectra Of The Α-Helical Protein Calexitin With The Dipole Interaction Model Including The N-Π* Transition, Akongnwi C. Jungong, Tsvetan Aleksandrov, Rahul Nori, Justin Erickson, Kathryn A. Thomasson, Igor V. Uporov, Ethan R. Austhof, Emily Holt, Felix N. Ngassa

Chemistry Faculty Publications

Circular dichroism (CD) is an important structural biology technique used to study protein dynamics, and most especially the secondary structure of peptides and proteins. Although CD is a technique that is relatively easy to introduce to undergraduate students, the high cost of obtaining a conventional CD instrument and the time required for sample preparation prevents a good number of students from having hands-on experiments demonstrating the principle of CD. Herein, theoretical circular dichroism with the dipole interaction model, DInaMo, is proposed as a tool for introducing students to CD. Using the dipole interaction model, the CD spectra of an α-helical …

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Chalcone And Cinnamate Synthesis Via One-Pot Enol Silane Formation-Mukaiyama Aldol Reactions Of Ketones And Acetate Esters, C. Wade Downey, Hadleigh M. Glist, Anna Takashima, Samuel R. Bottum, Grant J. Dixon Jan 2018

Chalcone And Cinnamate Synthesis Via One-Pot Enol Silane Formation-Mukaiyama Aldol Reactions Of Ketones And Acetate Esters, C. Wade Downey, Hadleigh M. Glist, Anna Takashima, Samuel R. Bottum, Grant J. Dixon

Chemistry Faculty Publications

Aryl alkyl ketones, acetate esters, and acetamides undergo facile one-pot enol silane formation, Mukaiyama aldol addition, and dehydrosilyloxylation in the presence of an amine base and excess trimethylsilyl trifluoromethanesulfonate. The chalcone and cinnamate products are generally recovered in high yield. The relative stoichiometry of the trimethylsilyl trifluoromethanesulfonate and amine base reagents determines whether the reaction yields the β- silyloxy carbonyl product or the α, β -unsaturated carbonyl.

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Testing The Underlying Chemical Principles Of The Biotic Ligand Model (Blm) To Marine Copper Systems: Measuring Copper Speciation Using Fluorescence Quenching, Tara N. Tait, James C. Mcgeer, Scott Smith Dec 2017

Testing The Underlying Chemical Principles Of The Biotic Ligand Model (Blm) To Marine Copper Systems: Measuring Copper Speciation Using Fluorescence Quenching, Tara N. Tait, James C. Mcgeer, Scott Smith

Chemistry Faculty Publications

Speciation of copper in marine systems strongly influences the ability of copper to cause toxicity. Natural organic matter (NOM) contains many binding sites which provides a protective effect on copper toxicity. The purpose of this study was to characterize copper binding with NOM using fluorescence quenching techniques. Fluorescence quenching of NOM with copper was performed on nine sea water samples. The resulting stability con- stants and binding capacities were consistent with literature values of marine NOM, show- ing strong binding with log K values from 7.64 to 10.2 and binding capacities ranging from 15 to 3110 nmole mg C −1 …

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Vibronically Coherent Ultrafast Triplet-Pair Formation And Subsequent Thermally Activated Dissociation Control Efficient Endothermic Singlet Fission, Hannah L. Stern, Alexandre Cheminal, Shane R. Yost, Katharina Broch, Sam L. Bayliss, Kai Chen, Maxim Tabachnyk, Karl J. Thorley, Neil Greenham, Justin Hodgkiss, John E. Anthony, Martin Head-Gordon, Andrew J. Musser, Akshay Rao, Richard H. Friend Dec 2017

Vibronically Coherent Ultrafast Triplet-Pair Formation And Subsequent Thermally Activated Dissociation Control Efficient Endothermic Singlet Fission, Hannah L. Stern, Alexandre Cheminal, Shane R. Yost, Katharina Broch, Sam L. Bayliss, Kai Chen, Maxim Tabachnyk, Karl J. Thorley, Neil Greenham, Justin Hodgkiss, John E. Anthony, Martin Head-Gordon, Andrew J. Musser, Akshay Rao, Richard H. Friend

Chemistry Faculty Publications

Singlet exciton fission (SF), the conversion of one spin-singlet exciton (S1) into two spin-triplet excitons (T1), could provide a means to overcome the Shockley–Queisser limit in photovoltaics. SF as measured by the decay of S1 has been shown to occur efficiently and independently of temperature, even when the energy of S1 is as much as 200 meV less than that of 2T1. Here we study films of triisopropylsilyltetracene using transient optical spectroscopy and show that the triplet pair state (TT), which has been proposed to mediate singlet fission, forms on ultrafast timescales …

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Eigenstate–Specific Temperatures In Two–Level Paramagnetic Spin Lattices, Mark Masthay, Calley N. Eads, Amber N. Johnson, R. Gerald Keil, Phillip Miller, Ross E. Jones, Joe D. Mashburn, Harry B. Fannin Dec 2017

Eigenstate–Specific Temperatures In Two–Level Paramagnetic Spin Lattices, Mark Masthay, Calley N. Eads, Amber N. Johnson, R. Gerald Keil, Phillip Miller, Ross E. Jones, Joe D. Mashburn, Harry B. Fannin

Chemistry Faculty Publications

Increasing interest in the thermodynamics of small and/or isolated systems, in combination with recent observations of negative temperatures of atoms in ultracold optical lattices, has stimulated the need for estimating the conventional, canonical temperature Tconvc of systems in equilibrium with heat baths using eigenstate-specific temperatures (ESTs). Four distinct ESTs—continuous canonical, discrete canonical, continuous microcanonical, and discrete microcanonical—are accordingly derived for two-level paramagnetic spin lattices (PSLs) in external magnetic fields. At large N, the four ESTs are intensive, equal to Tconvc, and obey all four laws of thermodynamics. In contrast, for N < 1000, the ESTs of most PSL eigenstates are non-intensive, differ from Tconvc, and violate each of the thermodynamic laws. Hence, in spite of their similarities to Tconvc at large N, the ESTs …

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The Warning On Saturated Fat: From Defective Experiments To Defective Guidelines, Fabian M. Dayrit Dec 2017

The Warning On Saturated Fat: From Defective Experiments To Defective Guidelines, Fabian M. Dayrit

Chemistry Faculty Publications

Coconut oil has been adversely affected by the current dietary guidelines that advocate a lowering of total fat and the replacement of saturated fat with polyunsaturated fat. This recommendation has its origins in the saturated fat-cholesterol-heart disease hypothesis that Ancel Keys first proposed in 1957. This hypothesis became an official recommendation with the publication of the Dietary Guidelines for Americans in 1980 and has been adopted by many other countries and international agencies. The dietary recommendations also warn against coconut oil. Recently, the American Heart Association re-issued this warning in its 2017 Presidential Advisory. However, a critical review of the …

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The Autophagy-Related Beclin-1 Protein Requires The Coiled-Coil And Bara Domains To Form A Homodimer With Submicromolar Affinity, Matthew J. Ranaghan, Michael A. Durney, Michael F. Mesleh, Patrick R. Mccarren, Colin W. Garvie, Douglas S. Daniels, Kimberly L. Carey, Adam P. Skepner, Beth Levine, Jose R. Perez Nov 2017

The Autophagy-Related Beclin-1 Protein Requires The Coiled-Coil And Bara Domains To Form A Homodimer With Submicromolar Affinity, Matthew J. Ranaghan, Michael A. Durney, Michael F. Mesleh, Patrick R. Mccarren, Colin W. Garvie, Douglas S. Daniels, Kimberly L. Carey, Adam P. Skepner, Beth Levine, Jose R. Perez

Chemistry Faculty Publications

Beclin-1 (BECN1) is an essential component of macroautophagy. This process is a highly conserved survival mechanism that recycles damaged cellular components or pathogens by encasing them in a bilayer vesicle that fuses with a lysosome to allow degradation of the vesicular contents. Mutations or altered expression profiles of BECN1 have been linked to various cancers and neurodegenerative diseases. Viruses, including HIV and herpes simplex virus 1 (HSV-1), are also known to specifically target BECN1 as a means of evading host defense mechanisms. Autophagy is regulated by the interaction between BECN1 and Bcl-2, a pro-survival protein in the apoptotic pathway that …

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The Future Perspective: Metabolomics In Laboratory Medicine For Inborn Errors Of Metabolism, Yana Sandlers Nov 2017

The Future Perspective: Metabolomics In Laboratory Medicine For Inborn Errors Of Metabolism, Yana Sandlers

Chemistry Faculty Publications

Metabolomics can be described as a simultaneous and comprehensive analysis of small molecules in a biological sample. Recent technological and bioinformatics advances have facilitated large-scale metabolomic studies in many areas, including inborn errors of metabolism (IEMs). Despite significant improvements in the diagnosis and treatment of some IEMs, it is still challenging to understand how genetic variation affects disease progression and susceptibility. In addition, a search for new more personalized therapies and a growing demand for tools to monitor the long-term metabolic effects of existing therapies set the stage for metabolomics integration in preclinical and clinical studies. While targeted metabolomics approach …

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Organelle-Specific Single-Molecule Imaging Of Α4Β2 Nicotinic Receptors Reveals The Effect Of Nicotine On Receptor Assembly And Cell-Surface Trafficking, Ashley M. Fox-Lee, Faruk H. Moonschi, Christopher I. Richards Oct 2017

Organelle-Specific Single-Molecule Imaging Of Α4Β2 Nicotinic Receptors Reveals The Effect Of Nicotine On Receptor Assembly And Cell-Surface Trafficking, Ashley M. Fox-Lee, Faruk H. Moonschi, Christopher I. Richards

Chemistry Faculty Publications

Nicotinic acetylcholine receptors (nAChRs) assemble in the endoplasmic reticulum (ER) and traffic to the cell surface as pentamers composed of α and β subunits. Many nAChR subtypes can assemble with varying subunit ratios, giving rise to multiple stoichiometries exhibiting different subcellular localization and functional properties. In addition to the endogenous neurotransmitter acetylcholine, nicotine also binds and activates nAChRs and influences their trafficking and expression on the cell surface. Currently, no available technique can specifically elucidate the stoichiometry of nAChRs in the ER versus those in the plasma membrane. Here, we report a method involving single-molecule fluorescence measurements to determine the …

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High-Statistics Β+/Ec-Decay Study Of 122Xe, B. Jigmeddorj, P. E. Garrett, C. A. Andreoiu, G. C. Ball, T. Bruhn, D. S. Cross, A. B. Garnsworthy, B. Hadinia, M. Moukaddam, J. Park, J. L. Pore, A. J. Radich, M. M. Rajabali, E. T. Rand, U. Rizwan, C. E. Svensson, P. Voss, Z. Wang, J. L. Wood, Steven W. Yates Oct 2017

High-Statistics Β+/Ec-Decay Study Of 122Xe, B. Jigmeddorj, P. E. Garrett, C. A. Andreoiu, G. C. Ball, T. Bruhn, D. S. Cross, A. B. Garnsworthy, B. Hadinia, M. Moukaddam, J. Park, J. L. Pore, A. J. Radich, M. M. Rajabali, E. T. Rand, U. Rizwan, C. E. Svensson, P. Voss, Z. Wang, J. L. Wood, Steven W. Yates

Chemistry Faculty Publications

Low-lying excited states of 122Xe have been studied via the β+/EC decay of 122Cs with the 8π γ-ray spectrometer at the TRIUMF Isotope Separator and Accelerator facility. The data collected have enabled the observation of new in-band transitions in the excited 0+ state bands. In addition, the 2+ members of the second 0+ and third 0+ state bands have been firmly confirmed by angular correlation analysis.

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Unmanned Aerial Systems For Monitoring Trace Tropospheric Gases, Travis J. Schuyler, Marcelo I. Guzman Oct 2017

Unmanned Aerial Systems For Monitoring Trace Tropospheric Gases, Travis J. Schuyler, Marcelo I. Guzman

Chemistry Faculty Publications

The emission of greenhouse gases (GHGs) has changed the composition of the atmosphere during the Anthropocene. Accurately documenting the sources and magnitude of GHGs emission is an important undertaking for discriminating the contributions of different processes to radiative forcing. Currently there is no mobile platform that is able to quantify trace gases at altitudes(UASs) can be deployed on-site in minutes and can support the payloads necessary to quantify trace gases. Therefore, current efforts combine the use of UASs available on the civilian market with inexpensively designed analytical systems for monitoring atmospheric trace gases. In this context, this perspective introduces the …

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Differentiating The Impact Of Nitrogen Chemical States On Optical Properties Of Nitrogen-Doped Graphene Quantum Dots, Timothy Pillar-Little, Doo Young Kim Oct 2017

Differentiating The Impact Of Nitrogen Chemical States On Optical Properties Of Nitrogen-Doped Graphene Quantum Dots, Timothy Pillar-Little, Doo Young Kim

Chemistry Faculty Publications

The optical properties of top-down synthesized oxidized graphene quantum dots (ox-GQDs) and nitrogen-incorporating graphene quantum dots (N-GQDs) along a range of hydrothermal treatment temperatures were observed. By controlling the hydrothermal treatment temperature, different chemical states of nitrogen atoms were incorporated into GQDs. Below 150 °C, edge-terminating amines and amides dominated the nitrogen content of N-GQDs. Above 150 °C, nitrogen was primarily present in the forms of pyridinic, pyrrolic and quaternary N. In addition to the absorbance and emission profiles of ox-GQDs and N-GQDs, pH-dependent emission spectra were collected to probe chemical states of nitrogen atoms and investigate the relationship between …

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Investigating Potential Pollutant Sources Causing Lack Of Biodiversity In Lytle Creek And Indian Run, Audrey E. Mcgowin, Amira Alsenbel, Harry Mcvey, Lori Williams, Taylor Stuckert Oct 2017

Investigating Potential Pollutant Sources Causing Lack Of Biodiversity In Lytle Creek And Indian Run, Audrey E. Mcgowin, Amira Alsenbel, Harry Mcvey, Lori Williams, Taylor Stuckert

Chemistry Faculty Publications

This report describes the results of research performed with funds from the Sture Fredrik Anliot Grant Fund granted in March 2016 and the Wright State University College of Science and Mathematics. The title of the grant was “Lytle Creek and Indian Run Sediment and Water Pollution Assessment” and its primary aim was to identify and measure pollutants that could be causing a lack of biodiversity in Lytle Creek in Wilmington, OH. The project formed the basis of Amira Alsenbel’s Masters in Chemistry thesis research.

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Spellbinding Effects Of The Acidic Cooh-Terminus Of Factor Va Heavy Chain On Prothrombinase Activity And Function, Jamila Hirbawi, Michael Kalafatis Sep 2017

Spellbinding Effects Of The Acidic Cooh-Terminus Of Factor Va Heavy Chain On Prothrombinase Activity And Function, Jamila Hirbawi, Michael Kalafatis

Chemistry Faculty Publications

Human factor Va (hfVa) is the important regulatory subunit of prothrombinase. Recent modeling data have suggested a critical role for amino acid Arg of hfVa for human prothrombin (hPro) activation by prothrombinase. Furthermore, it has also been demonstrated that hfVa has a different effect than that of bovine fVa on prethrombin-1 activation by prothrombinase. The difference between the two cofactor molecules was also found within the Asn-Arg dipeptide in the human factor V (hfV) molecule, which is replaced by the Asp-Glu sequence in bfV. As a consequence, we produced a recombinant hfV (rhfV) molecule with the substitution NR→DE. rhfV together …

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A Stimulated Emission Study Of The Ground State Bending Levels Of Bh2 Through The Barrier To Linearity And Ab Initio Calculations Of Near-Spectroscopic Accuracy, Bing Jin, Dennis J. Clouthier, Riccardo Tarroni Sep 2017

A Stimulated Emission Study Of The Ground State Bending Levels Of Bh2 Through The Barrier To Linearity And Ab Initio Calculations Of Near-Spectroscopic Accuracy, Bing Jin, Dennis J. Clouthier, Riccardo Tarroni

Chemistry Faculty Publications

The ground state bending levels of 11BH2 have been studied experimentally using a combination of low-resolution emission spectroscopy and high-resolution stimulated emission pumping (SEP) measurements. The data encompass the energy range below, through, and above the calculated position of the barrier to linearity. For the bending levels (0,3,0) and above, the data show substantial K-reordering, with the K"a = 1 levels falling well below those with K"a = 0. A comparison of the high-resolution rotationally resolved SEP data to our own very high level ab initio calculations of the rovibronic energy levels shows agreement approaching …

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Copper(Ii)- And Gold(Iii)-Mediated Cyclization Of A Thiourea To A Substituted 2-Aminobenzothiazole, Zachary W. Schroeder, L. K. Hiscock, Louise N. Dawe Sep 2017

Copper(Ii)- And Gold(Iii)-Mediated Cyclization Of A Thiourea To A Substituted 2-Aminobenzothiazole, Zachary W. Schroeder, L. K. Hiscock, Louise N. Dawe

Chemistry Faculty Publications

Benzothiazole derivatives are a class of privileged molecules due to their biological activity and pharmaceutical applications. One route to these molecules is via intramolecular cyclization of thioureas to form substituted 2-aminobenzothiazoles, but this often requires harsh conditions or employs expensive metal catalysts. Herein, the copper(II)- and gold(III)-mediated cyclizations of thioureas to substituted 2-aminobenzothiazoles are reported. The single-crystal X-ray structures of the thiourea N-(3-methoxyphenyl)-N'- (pyridin-2-yl)thiourea, C13H13N3OS, and the intermediate metal complexes aquabis[5-methoxy-N-(pyridin-2-yl-κN)-1,3-benzothiazol-2-amine-κN3]copper(II) dinitrate, [Cu(C13H11N3OS)2(H2O)](NO3) …

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Aquachlorido(2-{[6-(Dimethylamino)Pyrimidin-4- Yl]Sulfanyl}Pyrimidine-4,6-Diamine)Copper(Ii) Chloride Hydrate, Tristen E. Moyaert, Christina Paul, Weibin Chan, Amy A. Sarjeant, Louise N. Dawe Sep 2017

Aquachlorido(2-{[6-(Dimethylamino)Pyrimidin-4- Yl]Sulfanyl}Pyrimidine-4,6-Diamine)Copper(Ii) Chloride Hydrate, Tristen E. Moyaert, Christina Paul, Weibin Chan, Amy A. Sarjeant, Louise N. Dawe

Chemistry Faculty Publications

A copper(II) complex of the non-symmetric bidentate ligand 2-{[6-(di­methyl­amino)­pyrimidin-4-yl]sulfan­yl}pyrimidine-4,6-di­amine (L1) is reported. The single-crystal X-ray structure of aqua­[aqua/chlorido­(0.49/0.51)](2-{[6-(di­methyl­amino)­pyrimidin-4-yl]sulfan­yl}pyrimidine-4,6-di­amine)­copper(II) 0.49-chloride 1.51-hydrate, [CuCl1.51(C10H13N7S)(H2O)1.49]Cl0.49·1.51H2O or [(L1)Cl1.51(H2O)1.49Cu]0.49Cl·1.51H2O, exhibits distorted square-pyramidal geometry around the metal centre, with disorder in the axial position, occupied by chloride or water. The six-membered metal–chelate ring is in a boat conformation, and short inter­molecular S- - -S inter­actions are observed. In addition to its capacity for bidentate metal coordination, the ligand has …

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Development And Validation Of A Novel Lc–Ms/Ms Method For Simultaneous Determination Of Abiraterone And Its Seven Steroidal Metabolites In Human Serum: Innovation In Separation Of Diastereoisomers Without Use Of A Chiral Column, Mohammad Alyamani, Zhenfei Li, Sunil K. Upadhyay, David J. Anderson, Richard J. Auchus, Nima Sharifi Sep 2017

Development And Validation Of A Novel Lc–Ms/Ms Method For Simultaneous Determination Of Abiraterone And Its Seven Steroidal Metabolites In Human Serum: Innovation In Separation Of Diastereoisomers Without Use Of A Chiral Column, Mohammad Alyamani, Zhenfei Li, Sunil K. Upadhyay, David J. Anderson, Richard J. Auchus, Nima Sharifi

Chemistry Faculty Publications

Abiraterone acetate (AA), the prodrug of abiraterone, is FDA-approved for the treatment of castration-resistant prostate cancer. Abiraterone is metabolized in patients to a more potent analogue, D4A. However, we have recently reported that this analogue is further metabolized to additional metabolites in patients treated with AA. Here, we present a liquid chromatography-tandem mass spectrometry method developed to resolve and detect abiraterone and its seven metabolites in human serum using an AB Sciex Qtrap 5500 mass analyzer coupled with a Shimadzu Nexera UPLC station. Analytes and the internal standard (abiraterone-d4) were extracted from human serum using the liquid–liquid extraction procedure. The …

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Dietary Guidelines And Its Implications For Coconut Oil, Fabian M. Dayrit Sep 2017

Dietary Guidelines And Its Implications For Coconut Oil, Fabian M. Dayrit

Chemistry Faculty Publications

The dietary advice that is generally followed nationally and internationally closely follows the Dietary Guidelines for Americans which was first published in 1980 and which has been through eight editions. All of the editions of the Dietary Guidelines recommend a diet that is low in fat, and most editions recommend the replacement of saturated fat with polyunsaturated fat. This recommendation is based on the saturated fat-cholesterol-heart disease hypothesis that was first proposed by Ancel Keys in the 1950s. Coconut oil was labeled as unhealthy because of its high saturated fat composition. However, this label is unwarranted. Re-analysis of the work …

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Mukaiyama Addition Of (Trimethylsilyl) Acetonitrile To Dimethyl Acetals Mediated By Trimethylsilyl Trifluoromethanesulfonate, C. Wade Downey, Alice Y.-K. Lee, John R. Goodin, Courtney J. Botelho, William M. Stith Sep 2017

Mukaiyama Addition Of (Trimethylsilyl) Acetonitrile To Dimethyl Acetals Mediated By Trimethylsilyl Trifluoromethanesulfonate, C. Wade Downey, Alice Y.-K. Lee, John R. Goodin, Courtney J. Botelho, William M. Stith

Chemistry Faculty Publications

(Trimethylsilyl) acetonitrile reacts smoothly with dimethyl acetals in the presence of stoichiometric trimethylsilyl trifluoromethanesulfonate (TMSOTf) to yield β-methoxynitriles. The ideal substrates for this reaction are acetals derived from aromatic aldehydes. Elimination to the corresponding α,β-unsaturated nitriles is observed as the major product in the case of electron-rich acetals. A mechanistic hypothesis that includes isomerization of the silylnitrile to a nucleophilic N-silyl ketene imine is presented.

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Gold Nanoparticle Colorants As Traditional Ceramic Glaze Alternatives, Raef H. Lambertson, Christie A. Lacy, Samuel D. Gillespie, Michael C. Leopold Sep 2017

Gold Nanoparticle Colorants As Traditional Ceramic Glaze Alternatives, Raef H. Lambertson, Christie A. Lacy, Samuel D. Gillespie, Michael C. Leopold

Chemistry Faculty Publications

Historically, Roman stained glass has been a standard for high‐temperature color stability since biblical times but was not properly characterized as emission from nanoparticle plasmon resonance until the 1990s. The methods under which it was created have been lost, but some efforts have recently been made to recreate these properties using gold nanoparticle inks on glassy surfaces. This body of work employs gold nanoparticle systems ranging from 0.015% to 0.100% (wt/wt), suspended in a clear glaze body. The glazes are fired with traditional ceramic methods—in both gas reduction and electric oxidation kilns—in which nanoparticles are retained and can be imaged …

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