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Chemistry Faculty Publications

2017

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Articles 1 - 30 of 68

Full-Text Articles in Chemistry

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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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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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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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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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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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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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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Neurological Impact Of Zinc Excess And Deficiency In Vivo, Ronald Bartzatt Aug 2017

Neurological Impact Of Zinc Excess And Deficiency In Vivo, Ronald Bartzatt

Chemistry Faculty Publications

Zinc is an essential mineral that can cause pathological effects whether in excess or deficiency. Zinc is a component for over 250 enzymes and is required for cell growth, cell division, and cell function. Zinc is found in muscle and bones, with the prostrate, liver, skin, and kidney having detectable levels of zinc. However, zinc present in excess or deficiency can cause significant pathology in patients that include deleterious effects neurologically. Zinc in excess in vivo can cause focal neuronal pathology, while zinc deficiency can bring about mental lethargy, neuropsychiatric disorders, and reduced nerve conduction. Zinc is assimilated within the …

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Lanthanum-Mediated Dehydrogenation Of 1- And 2-Butynes: Spectroscopy And Formation Of La(C4H4) Isomers, Wenjin Cao, Dilrukshi C. Hewage, Dong-Sheng Yang Aug 2017

Lanthanum-Mediated Dehydrogenation Of 1- And 2-Butynes: Spectroscopy And Formation Of La(C4H4) Isomers, Wenjin Cao, Dilrukshi C. Hewage, Dong-Sheng Yang

Chemistry Faculty Publications

La atom reactions with 1-butyne and 2-butyne are carried out in a laser-vaporization molecular beam source. Both reactions yield the same La-hydrocarbon products from the dehydrogenation and carbon-carbon bond cleavage and coupling of the butynes. The dehydrogenated species La(C4H4) is characterized with mass-analyzed threshold ionization (MATI) spectroscopy and quantum chemical computations. The MATI spectra of La(C4H4) produced from the two reactions exhibit two identical transitions, each consisting of a strong origin band and several vibrational intervals. The two transitions are assigned to the ionization of two isomers: La(η4–CH2CCCH …

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Real-Time Sensing Of Single-Ligand Delivery With Nanoaperture-Integrated Microfluidic Devices, W. Elliott Martin, Ning Ge, Bernadeta R. Srijanto, Emily Furnish, C. Patrick Collier, Christine A. Trinkle, Christopher I. Richards Jul 2017

Real-Time Sensing Of Single-Ligand Delivery With Nanoaperture-Integrated Microfluidic Devices, W. Elliott Martin, Ning Ge, Bernadeta R. Srijanto, Emily Furnish, C. Patrick Collier, Christine A. Trinkle, Christopher I. Richards

Chemistry Faculty Publications

The measurement of biological events on the surface of live cells at the single-molecule level is complicated by several factors including high protein densities that are incompatible with single-molecule imaging, cellular autofluorescence, and protein mobility on the cell surface. Here, we fabricated a device composed of an array of nanoscale apertures coupled with a microfluidic delivery system to quantify single-ligand interactions with proteins on the cell surface. We cultured live cells directly on the device and isolated individual epidermal growth factor receptors (EGFRs) in the apertures while delivering fluorescently labeled epidermal growth factor. We observed single ligands binding to EGFRs, …

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Level Lifetimes And The Structure Of 134Xe From Inelastic Neutron Scattering, Erin E. Peters, Anagha Chakraborty, Benjamin P. Crider, S. F. Ashley, E. Elhami, S. F. Hicks, A. Kumar, Marcus T. Mcellistrem, Sharmistha Mukhopadhyay, J. N. Orce, Francisco M. Prados-Estévez, Steven W. Yates Jul 2017

Level Lifetimes And The Structure Of 134Xe From Inelastic Neutron Scattering, Erin E. Peters, Anagha Chakraborty, Benjamin P. Crider, S. F. Ashley, E. Elhami, S. F. Hicks, A. Kumar, Marcus T. Mcellistrem, Sharmistha Mukhopadhyay, J. N. Orce, Francisco M. Prados-Estévez, Steven W. Yates

Chemistry Faculty Publications

The level structure of 134Xe was studied with the inelastic neutron scattering reaction followed by γ-ray detection. A number of level lifetimes were determined for the first time with the Doppler-shift attenuation method and the low-lying excited states were characterized. From this new spectroscopic information, the third excited state, a 0+ level which had only been observed in a previous inelastic neutron scattering study, was verified. Reduced transition probabilities were calculated; comparisons were drawn with a vibrational description of the nucleus and found lacking. The 3− octupole phonon has been confirmed, and the complete negative-parity multiplet …

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The Entangled Triplet Pair State In Acene And Heteroacene Materials, Chaw Keong Yong, Andrew J. Musser, Sam L. Bayliss, Steven Lukman, Hiroyuki Tamura, Olga Bubnova, Rawad Hallani, Aurélie Meneau, Roland Resel, Munetaka Maruyama, Shu Hotta, Laura M. Herz, David Beljonne, John E. Anthony, Jenny Clark, Henning Sirringhaus Jul 2017

The Entangled Triplet Pair State In Acene And Heteroacene Materials, Chaw Keong Yong, Andrew J. Musser, Sam L. Bayliss, Steven Lukman, Hiroyuki Tamura, Olga Bubnova, Rawad Hallani, Aurélie Meneau, Roland Resel, Munetaka Maruyama, Shu Hotta, Laura M. Herz, David Beljonne, John E. Anthony, Jenny Clark, Henning Sirringhaus

Chemistry Faculty Publications

Entanglement of states is one of the most surprising and counter-intuitive consequences of quantum mechanics, with potent applications in cryptography and computing. In organic materials, one particularly significant manifestation is the spin-entangled triplet-pair state, which mediates the spin-conserving fission of one spin-0 singlet exciton into two spin-1 triplet excitons. Despite long theoretical and experimental exploration, the nature of the triplet-pair state and inter-triplet interactions have proved elusive. Here we use a range of organic semiconductors that undergo singlet exciton fission to reveal the photophysical properties of entangled triplet-pair states. We find that the triplet pair is bound with respect to …

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Mechanism-Informed Refinement Reveals Altered Substrate-Binding Mode For Catalytically Competent Nitroreductase, Warintra Pitsawong, Chad A. Haynes, Ronald L. Koder, David W. Rodgers, Anne-Frances Miller Jul 2017

Mechanism-Informed Refinement Reveals Altered Substrate-Binding Mode For Catalytically Competent Nitroreductase, Warintra Pitsawong, Chad A. Haynes, Ronald L. Koder, David W. Rodgers, Anne-Frances Miller

Chemistry Faculty Publications

Nitroreductase from Enterobacter cloacae (NR) reduces diverse nitroaromatics including herbicides, explosives and prodrugs, and holds promise for bioremediation, prodrug activation and enzyme-assisted synthesis. We solved crystal structures of NR complexes with bound substrate or analog for each of its two half-reactions. We complemented these with kinetic isotope effect (KIE) measurements elucidating H-transfer steps essential to each half-reaction. KIEs indicate hydride transfer from NADH to the flavin consistent with our structure of NR with the NADH analog nicotinic acid adenine dinucleotide (NAAD). The KIE on reduction of p-nitrobenzoic acid (p-NBA) also indicates hydride transfer, and requires revision of …

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Library Of Microcrystalline Tests For Novel Psychoactive Substances, Matthew Quinn, Michael Cain Jr., Monica Joshi Jun 2017

Library Of Microcrystalline Tests For Novel Psychoactive Substances, Matthew Quinn, Michael Cain Jr., Monica Joshi

Chemistry Faculty Publications

A microcrystalline test is a precipitation reaction between a drug and a reagent, forming an insoluble drug-reagent complex that is unique to that specific test. These tests are quick, requiring minimal sample preparation and can be non-destructive. Therefore, they can be used as preliminary and confirmatory tests with expertise. Microcrystalline tests are one of the oldest analytical chemistry practices and their use for classic drugs such as cocaine, heroin and amphetamines is well-documented. However, there is very limited research on microcrystalline tests for the novel compounds encountered by law enforcement today. This research is an effort to increase understanding and …

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Inhibiting Translesion Dna Synthesis As An Approach To Combat Drug Resistance To Dna Damaging Agents, Jung-Suk Choi, Seol Kim, Edward Motea, Anthony J. Berdis Jun 2017

Inhibiting Translesion Dna Synthesis As An Approach To Combat Drug Resistance To Dna Damaging Agents, Jung-Suk Choi, Seol Kim, Edward Motea, Anthony J. Berdis

Chemistry Faculty Publications

Anti-cancer agents exert therapeutic effects by damaging DNA. Unfortunately, DNA polymerases can effectively replicate the formed DNA lesions to cause drug resistance and create more aggressive cancers. To understand this process at the cellular level, we developed an artificial nucleoside that visualizes the replication of damaged DNA to identify cells that acquire drug resistance through this mechanism. Visualization is achieved using "click" chemistry to covalently attach azide-containing fluorophores to the ethynyl group present on the nucleoside analog after its incorporation opposite damaged DNA. Flow cytometry and microscopy techniques demonstrate that the extent of nucleotide incorporation into genomic DNA is enhanced …

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Neutron Scattering Cross Section Measurements For 56Fe, Anthony Paul D. Ramirez, J. Vanhoy, S. F. Hicks, Marcus T. Mcellistrem, Erin E. Peters, Sharmistha Mukhopadhyay, T. D. Harrison, T. J. Howard, D. T. Jackson, P. D. Lenzen, T. D. Nguyen, R. L. Pecha, B. G. Rice, B. K. Thompson, Steven W. Yates Jun 2017

Neutron Scattering Cross Section Measurements For 56Fe, Anthony Paul D. Ramirez, J. Vanhoy, S. F. Hicks, Marcus T. Mcellistrem, Erin E. Peters, Sharmistha Mukhopadhyay, T. D. Harrison, T. J. Howard, D. T. Jackson, P. D. Lenzen, T. D. Nguyen, R. L. Pecha, B. G. Rice, B. K. Thompson, Steven W. Yates

Chemistry Faculty Publications

Elastic and inelastic differential cross sections for neutron scattering from 56Fe have been measured for several incident energies from 1.30 to 7.96 MeV at the University of Kentucky Accelerator Laboratory. Scattered neutrons were detected using a C6D6 liquid scintillation detector using pulse-shape discrimination and time-of-flight techniques. The deduced cross sections have been compared with previously reported data, predictions from evaluation databases ENDF, JENDL, and JEFF, and theoretical calculations performed using different optical model potentials using the TALYS and EMPIRE nuclear reaction codes. The coupled-channel calculations based on the vibrational and soft-rotor models are found to describe …

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Crystal Structure Of 4,4′-Bis­­[3-(Piperidin-1-Yl)Prop-1-Yn-1-Yl]-1,1′-Biphen­Yl, Anqi Walbaum, E. Kim Fifer, Sean R. Parkin, Peter A. Crooks Jun 2017

Crystal Structure Of 4,4′-Bis­­[3-(Piperidin-1-Yl)Prop-1-Yn-1-Yl]-1,1′-Biphen­Yl, Anqi Walbaum, E. Kim Fifer, Sean R. Parkin, Peter A. Crooks

Chemistry Faculty Publications

The title compound, C28H32N2, (I), is one of a second generation of compounds designed and synthesized based on a very potent and selective α9α10 nicotinic acetyl­choline receptor antagonist ZZ161C {1,1′-[[1,1′-biphen­yl]-4,4′-diylbis(prop-2-yne-3,1-di­yl)]bis­(3,4-di­methyl­pyridin-1-ium) bromide}, which has shown analgesic effects in a chemotherapy-induced neuropathy animal model. Compound (I) was synthesized by the reaction of 4,4′-bis­(3-bromo­prop-1-yn-1-yl)-1,1′-biphenyl with piperidine at room temperature in aceto­nitrile. The single-crystal used for X-ray analysis was obtained by dissolving (I) in a mixture of di­chloro­methane and methanol, followed by slow evaporation of the solvent. In the crystal of (I), the biphenyl moiety has a twisted …

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Copalic Acid Analogs Down-Regulate Androgen Receptor And Inhibit Small Chaperone Protein, Nethrie D. Idippily, Qiaoyun Zheng, Chunfang Gan, Aicha Quamine, Morgan M. Ashcraft, Bo Zhong, Bin Su Ph.D. Jun 2017

Copalic Acid Analogs Down-Regulate Androgen Receptor And Inhibit Small Chaperone Protein, Nethrie D. Idippily, Qiaoyun Zheng, Chunfang Gan, Aicha Quamine, Morgan M. Ashcraft, Bo Zhong, Bin Su Ph.D.

Chemistry Faculty Publications

Copalic acid, one of the diterpenoid acids in copaiba oil, inhibited the chaperone function of α-crystallin and heat shock protein 27 kD (HSP27). It also showed potent activity in decreasing an HSP27 client protein, androgen receptor (AR), which makes it useful in prostate cancer treatment or prevention. To develop potent drug candidates to decrease the AR level in prostate cancer cells, more copalic acid analogs were synthesized. Using the level of AR as the readout, 15 of the copalic acid analogs were screened and two compounds were much more potent than copalic acid. The compounds also dose-dependently inhibited AR positive …

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