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2015

University of Kentucky

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Articles 31 - 60 of 311

Full-Text Articles in Physical Sciences and Mathematics

Revisiting Scalar Glueballs, Hai-Yang Cheng, Chun-Khiang Chua, Keh-Fei Liu Nov 2015

Revisiting Scalar Glueballs, Hai-Yang Cheng, Chun-Khiang Chua, Keh-Fei Liu

Physics and Astronomy Faculty Publications

It is commonly believed that the lowest-lying scalar glueball lies somewhere in the isosinglet scalar mesons f0(1370), f0(1500) and f0(1710) denoted generically by f0. In this work we consider lattice calculations and experimental data to infer the glue and qq components of f0. These include the calculations of the scalar glueball masses in quenched and unquenched lattice QCD, measurements of the radiative decays J/ψ→γf0, the ratio of f0 decays to ππ, KK and ηη, the ratio of J/ψ decays …

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A Catalog Of Visual-Like Morphologies In The 5 Candels Fields Using Deep Learning, M. Huertas-Company, R. Gravet, G. Cabrera-Vives, Pablo G. Pérez-González, J. Kartaltepe, Guillermo Barro, M. Bernardi, S. Mei, F. Shankar, P. Dimauro, E. F. Bell, Dale D. Kocevski, David C. Koo, Sandra M. Faber, Daniel H. Mcintosh Nov 2015

A Catalog Of Visual-Like Morphologies In The 5 Candels Fields Using Deep Learning, M. Huertas-Company, R. Gravet, G. Cabrera-Vives, Pablo G. Pérez-González, J. Kartaltepe, Guillermo Barro, M. Bernardi, S. Mei, F. Shankar, P. Dimauro, E. F. Bell, Dale D. Kocevski, David C. Koo, Sandra M. Faber, Daniel H. Mcintosh

Physics and Astronomy Faculty Publications

We present a catalog of visual-like H-band morphologies of ~50.000 galaxies (Hf160w < 24.5) in the 5 CANDELS fields (GOODS-N, GOODS-S, UDS, EGS, and COSMOS). Morphologies are estimated using Convolutional Neural Networks (ConvNets). The median redshift of the sample is 〈z〉 ~ 1.25. The algorithm is trained on GOODS-S, for which visual classifications are publicly available, and then applied to the other 4 fields. Following the CANDELS main morphology classification scheme, our model retrieves for each galaxy the probabilities of having a spheroid or a disk, presenting an irregularity, being compact or a point source, and being unclassifiable. ConvNets are able to predict the fractions of votes given to a galaxy image with zero bias and ~10% scatter. The fraction of mis-classifications is …

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Measurement Of The Target-Normal Single-Spin Asymmetry In Quasielastic Scattering From The Reaction 3He↑(E,E′ ), Chiranjib Dutta, Wolfgang Korsch, Y.-W. Zhang, E. Long, M. Mihovilovič, G. Jin, K. Allada, B. Anderson, J. R. M. Annand, T. Averett, C. Ayerbe-Gayoso, W. Boeglin Oct 2015

Measurement Of The Target-Normal Single-Spin Asymmetry In Quasielastic Scattering From The Reaction 3He↑(E,E′ ), Chiranjib Dutta, Wolfgang Korsch, Y.-W. Zhang, E. Long, M. Mihovilovič, G. Jin, K. Allada, B. Anderson, J. R. M. Annand, T. Averett, C. Ayerbe-Gayoso, W. Boeglin

Physics and Astronomy Faculty Publications

We report the first measurement of the target single-spin asymmetry, Ay, in quasielastic scattering from the inclusive reaction 3He↑(e,e′ ) on a 3He gas target polarized normal to the lepton scattering plane. Assuming time-reversal invariance, this asymmetry is strictly zero for one-photon exchange. A nonzero Ay can arise from the interference between the one- and two-photon exchange processes which is sensitive to the details of the substructure of the nucleon. An experiment recently completed at Jefferson Lab yielded asymmetries with high statistical precision at Q2=0.13, 0.46, and …

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Spin Nematics, Valence-Bond Solids, And Spin Liquids In So(N) Quantum Spin Models On The Triangular Lattice, Ribhu K. Kaul Oct 2015

Spin Nematics, Valence-Bond Solids, And Spin Liquids In So(N) Quantum Spin Models On The Triangular Lattice, Ribhu K. Kaul

Physics and Astronomy Faculty Publications

We introduce a simple model of SO(N) spins with two-site interactions which is amenable to quantum Monte Carlo studies without a sign problem on nonbipartite lattices. We present numerical results for this model on the two-dimensional triangular lattice where we find evidence for a spin nematic at small N, a valence-bond solid at large N, and a quantum spin liquid at intermediate N. By the introduction of a sign-free four-site interaction, we uncover a rich phase diagram with evidence for both first-order and exotic continuous phase transitions.

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The Nicotine Metabolite, Cotinine, Alters The Assembly And Trafficking Of A Subset Of Nicotinic Acetylcholine Receptors, Ashley M. Fox, Faruk H. Moonschi, Christopher I. Richards Oct 2015

The Nicotine Metabolite, Cotinine, Alters The Assembly And Trafficking Of A Subset Of Nicotinic Acetylcholine Receptors, Ashley M. Fox, Faruk H. Moonschi, Christopher I. Richards

Chemistry Faculty Publications

Exposure to nicotine alters the trafficking and assembly of nicotinic receptors (nAChRs), leading to their up-regulation on the plasma membrane. Although the mechanism is not fully understood, nicotine-induced up-regulation is believed to contribute to nicotine addiction. The effect of cotinine, the primary metabolite of nicotine, on nAChR trafficking and assembly has not been extensively investigated. We utilize a pH-sensitive variant of GFP, super ecliptic pHluorin, to differentiate between intracellular nAChRs and those expressed on the plasma membrane to quantify changes resulting from cotinine and nicotine exposure. Similar to nicotine, exposure to cotinine increases the number of α4β2 receptors on the …

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Comparison Of The Crystal Structures Of 4,4′-Bis­­[3-(4-Methyl­Piperidin-1-Yl)Prop-1-Yn-1-Yl]-1,1′-Bi­Phenyl And 4,4′-Bis­­[3-(2,2,6,6-Tetra­Methyl­Piperidin-1-Yl)Prop-1-Yn-1-Yl]-1,1′-Biphen­Yl, Anqi Wan, Narsimha Reddy Penthala, E. Kim Fifer, Sean Parkin, Peter A. Crooks Oct 2015

Comparison Of The Crystal Structures Of 4,4′-Bis­­[3-(4-Methyl­Piperidin-1-Yl)Prop-1-Yn-1-Yl]-1,1′-Bi­Phenyl And 4,4′-Bis­­[3-(2,2,6,6-Tetra­Methyl­Piperidin-1-Yl)Prop-1-Yn-1-Yl]-1,1′-Biphen­Yl, Anqi Wan, Narsimha Reddy Penthala, E. Kim Fifer, Sean Parkin, Peter A. Crooks

Chemistry Faculty Publications

As part of a comprehensive program to discover α9α10 nicotinic acetyl­choline receptor antagonists, the title compounds C30H36N2, (I), and C36H48N2, (II), were synthesized by coupling 4,4′-bis­(3-bromo­prop-1-yn-1-yl)-1,1′-biphenyl with 4-methyl­piperidine and 2,2,6,6-tetra­methyl­piperidine, respectively, in aceto­nitrile at room temperature. In compound (I), the biphenyl system has a twisted conformation with a dihedral angle of 26.57 (6)° between the two phenyl rings of the biphenyl moiety, while in compound (II), the biphenyl moiety sits on a crystallographic inversion centre so the two phenyl rings are exactly coplanar. The terminal piperidine rings in …

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Comparison Crystal Structure Conformations Of Two Structurally Related Biphenyl Analogues: 4,4'-Bis[3-(Pyrrolidin-1-Yl)Prop-1-Yn-1-Yl]-1,1'-Biphenyl And 4,4'-Bis{3-[(S)-2-Methylpyrrolidin-1-Yl]Prop-1-Yn-1-Yl}-1,1'-Biphenyl, Anqi Wan, Narsimha Reddy Penthala, E. Kim Fifer, Sean Parkin, Peter A. Crooks Oct 2015

Comparison Crystal Structure Conformations Of Two Structurally Related Biphenyl Analogues: 4,4'-Bis[3-(Pyrrolidin-1-Yl)Prop-1-Yn-1-Yl]-1,1'-Biphenyl And 4,4'-Bis{3-[(S)-2-Methylpyrrolidin-1-Yl]Prop-1-Yn-1-Yl}-1,1'-Biphenyl, Anqi Wan, Narsimha Reddy Penthala, E. Kim Fifer, Sean Parkin, Peter A. Crooks

Chemistry Faculty Publications

The title compounds, C26H28N2, (I), and C28H32N2, (II), were designed based on the structure of the potent 910 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}. In order to improve the druglikeness properties of ZZ161C for potential oral administration, the title compounds (I) and (II) were prepared by coupling 4,4'-bis­(3-bromo­prop-1-yn-1-yl)-1,1'-biphenyl with pyrrol­idine, (I), and (S)-2-methyl­pyrrolidine, (II), respectively, in aceto­nitrile at room temperature. The asymmetric unit of (I) contains two half mol­ecules that each sit on sites of crystallographic inversion. As a result, the biphenyl ring systems in …

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Functional Linear Models Extensions Uncover Pleiotropic Effects Of Chronic Pain Phenotypes, Dmitri V. Zaykin, L. Qing, G. D. Slade, R. Dubner, R. B. Fillingim, J. D. Greenspan, R. Ohrbach, W. Maixner, L. B. Diatchenko, Olga A. Vsevolozhskaya Oct 2015

Functional Linear Models Extensions Uncover Pleiotropic Effects Of Chronic Pain Phenotypes, Dmitri V. Zaykin, L. Qing, G. D. Slade, R. Dubner, R. B. Fillingim, J. D. Greenspan, R. Ohrbach, W. Maixner, L. B. Diatchenko, Olga A. Vsevolozhskaya

Biostatistics Presentations

Growing scientific evidence suggests that intricate interactions of genetic risk factors with environmental exposures play a major role in the development of chronic pain conditions. In studies of relative contribution of an individual’s genetic composition to the perception of pain, the general characteristics of pain sensitivity are typically measured by a wide range of different, yet possibly etiologically related pain phenotypes. Testing each of these pain-perception traits individually is subject to problems of multiple testing and low statistical power. Furthermore, pain-related traits may share common etiology and comprise binary, categorical, and quantitative measurements. In the current study, we propose a …

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Deep Chandra, Hst-Cos, And Megacam Observations Of The Phoenix Cluster: Extreme Star Formation And Agn Feedback On Hundred Kiloparsec Scales, Michael Mcdonald, B. R. Mcnamara, Reinout J. Van Weeren, Douglas E. Applegate, Matthew Bayliss, Marshall W. Bautz, Bradford A. Benson, John E. Carlstrom, Lindsey E. Bleem, Marios Chatzikos, A. C. Edge, A. C. Fabian, Gordon P. Garmire, Julie Hlavacek-Larrondo, Christine Jones-Forman, Adam B. Mantz, Eric D. Miller, Brian Stalder, Sylvain Veilleux, John A. Zuhone Sep 2015

Deep Chandra, Hst-Cos, And Megacam Observations Of The Phoenix Cluster: Extreme Star Formation And Agn Feedback On Hundred Kiloparsec Scales, Michael Mcdonald, B. R. Mcnamara, Reinout J. Van Weeren, Douglas E. Applegate, Matthew Bayliss, Marshall W. Bautz, Bradford A. Benson, John E. Carlstrom, Lindsey E. Bleem, Marios Chatzikos, A. C. Edge, A. C. Fabian, Gordon P. Garmire, Julie Hlavacek-Larrondo, Christine Jones-Forman, Adam B. Mantz, Eric D. Miller, Brian Stalder, Sylvain Veilleux, John A. Zuhone

Physics and Astronomy Faculty Publications

We present new ultraviolet, optical, and X-ray data on the Phoenix galaxy cluster (SPT-CLJ2344-4243). Deep optical imaging reveals previously undetected filaments of star formation, extending to radii of ~50–100 kpc in multiple directions. Combined UV-optical spectroscopy of the central galaxy reveals a massive (2 x 109 M⊙), young (~4.5 Myr) population of stars, consistent with a time-averaged star formation rate of 610 ± 50 M⊙ yr−1. We report a strong detection of O ᴠɪ λλ1032,1038, which appears to originate primarily in shock-heated gas, but may contain a substantial contribution (>1000 M⊙ …

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Numerical Studies Of Various Néel-Vbs Transitions In Su(N) Anti-Ferromagnets, Ribhu K. Kaul, Matthew S. Block Sep 2015

Numerical Studies Of Various Néel-Vbs Transitions In Su(N) Anti-Ferromagnets, Ribhu K. Kaul, Matthew S. Block

Physics and Astronomy Faculty Publications

In this manuscript we review recent developments in the numerical simulations of bipartite SU(N) spin models by quantum Monte Carlo (QMC) methods. We provide an account of a large family of newly discovered sign-problem free spin models which can be simulated in their ground states on large lattices, containing O(105) spins, using the stochastic series expansion method with efficient loop algorithms. One of the most important applications so far of these Hamiltonians are to unbiased studies of quantum criticality between Neel and valence bond phases in two dimensions - a summary of this body of …

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Heterogeneous Oxidation Of Catechol, Elizabeth A. Pillar, Ruixin Zhou, Marcelo I. Guzman Sep 2015

Heterogeneous Oxidation Of Catechol, Elizabeth A. Pillar, Ruixin Zhou, Marcelo I. Guzman

Chemistry Faculty Publications

Natural and anthropogenic emissions of aromatic hydrocarbons from biomass burning, agro-industrial settings, and fossil fuel combustion contribute precursors to secondary aerosol formation (SOA). How these compounds are processed under humid tropospheric conditions is the focus of current attention to understand their environmental fate. This work shows how catechol thin films, a model for oxygenated aromatic hydrocarbons present in biomass burning and combustion aerosols, undergo heterogeneous oxidation at the air–solid interface under variable relative humidity (RH = 0–90%). The maximum reactive uptake coefficient of O3(g) by catechol γO3 = (7.49 ± 0.35) × 10–6 occurs for …

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Patient-Specific Variations In Biomarkers Across Gingivitis And Periodontitis, Radhakrishnan Nagarajan, Craig S. Miller, Dolph Dawson, Mohanad Al-Sabbagh, J. L. Ebersole Sep 2015

Patient-Specific Variations In Biomarkers Across Gingivitis And Periodontitis, Radhakrishnan Nagarajan, Craig S. Miller, Dolph Dawson, Mohanad Al-Sabbagh, J. L. Ebersole

Biostatistics Faculty Publications

This study investigates the use of saliva, as an emerging diagnostic fluid in conjunction with classification techniques to discern biological heterogeneity in clinically labelled gingivitis and periodontitis subjects (80 subjects; 40/group) A battery of classification techniques were investigated as traditional single classifier systems as well as within a novel selective voting ensemble classification approach (SVA) framework. Unlike traditional single classifiers, SVA is shown to reveal patient-specific variations within disease groups, which may be important for identifying proclivity to disease progression or disease stability. Salivary expression profiles of IL-1ß, IL-6, MMP-8, and MIP-1α from 80 patients were analyzed using four classification …

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Convergence Rates And Hölder Estimates In Almost-Periodic Homogenization Of Elliptic Systems, Zhongwei Shen Sep 2015

Convergence Rates And Hölder Estimates In Almost-Periodic Homogenization Of Elliptic Systems, Zhongwei Shen

Mathematics Faculty Publications

For a family of second-order elliptic systems in divergence form with rapidly oscillating, almost-periodic coefficients, we obtain estimates for approximate correctors in terms of a function that quantifies the almost periodicity of the coefficients. The results are used to investigate the problem of convergence rates. We also establish uniform Hölder estimates for the Dirichlet problem in a bounded C1,α domain.

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Localization Length Scales Of Triplet Excitons In Singlet Fission Materials, Sam L. Bayliss, Karl J. Thorley, John E. Anthony, Hélène Bouchiat, Neil C. Greenham, Alexei D. Chepelianskii Sep 2015

Localization Length Scales Of Triplet Excitons In Singlet Fission Materials, Sam L. Bayliss, Karl J. Thorley, John E. Anthony, Hélène Bouchiat, Neil C. Greenham, Alexei D. Chepelianskii

Chemistry Faculty Publications

We measure the dielectric confinement length scales of triplet excitons in organic semiconductors by jointly measuring their microwave-domain electric and magnetic susceptibilities. We apply this technique to characterize triplet excitons in two singlet fission materials with distinct solid-state packing and correlate the extracted localization length scales with the role of the excitonic environment. By using the magnetic susceptibility simultaneously determined through our experiments, we compare the independently extracted dielectric and spin-spin localization length scales, highlighting the role of local anisotropy on the properties of excitonic triplet states.

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Electrically Tunable Transport In The Antiferromagnetic Mott Insulator Sr2Iro4, C. Wang, H. Seinige, Gang Cao, J.-S. Zhou, J. B. Goodenough, M. Tsoi Sep 2015

Electrically Tunable Transport In The Antiferromagnetic Mott Insulator Sr2Iro4, C. Wang, H. Seinige, Gang Cao, J.-S. Zhou, J. B. Goodenough, M. Tsoi

Physics and Astronomy Faculty Publications

Electronic transport properties of the antiferromagnetic Mott insulator Sr2IrO4 have been investigated under extremely high electric biases. Using nanoscale contacts, we apply electric fields up to a few MV/m to a single crystal of Sr2IrO4 and observe a continuous reduction in the material's resistivity with increasing bias, characterized by a reduction in the transport activation energy by as much as 16%. Temperature-dependent resistivity measurements provide a means to unambiguously retrieve the bias dependence of the activation energy from the Arrhenius plots at different biases. We further demonstrate the feasibility of reversible resistive switching induced …

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Far From 'Easy' Spectroscopy With The 8Π And Griffin Spectrometers At Triumf-Isac, Steven W. Yates, P. E. Garrett, A. J. Radich, J. M. Allmond, C. Andreoiu, G. C. Ball, P. C. Bender, L. Bianco, V. Bildstein, H. Bidaman, R. Braid Sep 2015

Far From 'Easy' Spectroscopy With The 8Π And Griffin Spectrometers At Triumf-Isac, Steven W. Yates, P. E. Garrett, A. J. Radich, J. M. Allmond, C. Andreoiu, G. C. Ball, P. C. Bender, L. Bianco, V. Bildstein, H. Bidaman, R. Braid

Chemistry Faculty Publications

The 8π spectrometer, installed at the TRIUMF-ISAC facility, was the world's most sensitive γ-ray spectrometer dedicated to β-decay studies. A description is given of the 8π spectrometer and its auxiliary detectors including the plastic scintillator array SCEPTAR used for β-particle tagging and the Si(Li) array PACES for conversion electron measurements, its moving tape collector, and its data acquisition system. The recent investigation of the decay of 124Cs to study the nuclear structure of 124Xe, and how the β-decay measurements complemented previous Coulomb excitation studies, is highlighted, including the extraction of the deformation parameters for the excited 0+ …

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The Nature And Frequency Of Outflows From Stars In The Central Orion Nebula Cluster, C. R. O'Dell, Gary J. Ferland, W. J. Henney, M. Peimbert, Ma. T. García-Díaz, Robert H. Rubin Sep 2015

The Nature And Frequency Of Outflows From Stars In The Central Orion Nebula Cluster, C. R. O'Dell, Gary J. Ferland, W. J. Henney, M. Peimbert, Ma. T. García-Díaz, Robert H. Rubin

Physics and Astronomy Faculty Publications

Recent Hubble Space Telescope images have allowed the determination with unprecedented accuracy of motions and changes of shocks within the inner Orion Nebula. These originate from collimated outflows from very young stars, some within the ionized portion of the nebula and others within the host molecular cloud. We have doubled the number of Herbig–Haro objects known within the inner Orion Nebula. We find that the best-known Herbig–Haro shocks originate from relatively few stars, with the optically visible X-ray source COUP 666 driving many of them. While some isolated shocks are driven by single collimated outflows, many groups of shocks are …

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Ultraviolet Luminosity Density Of The Universe During The Epoch Of Reionization, Ketron Mitchell-Wynne, Asantha Cooray, Yan Gong, Matthew Ashby, Timothy Dolch, Henry Ferguson, Steven Finkelstein, Norman Grogin, Dale D. Kocevski, Anton Koekemoer, Joel Primack, Joseph Smidt Sep 2015

Ultraviolet Luminosity Density Of The Universe During The Epoch Of Reionization, Ketron Mitchell-Wynne, Asantha Cooray, Yan Gong, Matthew Ashby, Timothy Dolch, Henry Ferguson, Steven Finkelstein, Norman Grogin, Dale D. Kocevski, Anton Koekemoer, Joel Primack, Joseph Smidt

Physics and Astronomy Faculty Publications

The spatial fluctuations of the extragalactic background light trace the total emission from all stars and galaxies in the Universe. A multiwavelength study can be used to measure the integrated emission from first galaxies during reionization when the Universe was about 500 million years old. Here we report arcmin-scale spatial fluctuations in one of the deepest sky surveys with the Hubble Space Telescope in five wavebands between 0.6 and 1.6 μm. We model-fit the angular power spectra of intensity fluctuation measurements to find the ultraviolet luminosity density of galaxies at redshifts greater than 8 to be log ρUV = …

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Quantitative Analysis Of The Density Of Trap States At The Semiconductor-Dielectric Interface In Organic Field-Effect Transistors, Peter J. Diemer, Zachary A. Lamport, Yaochuan Mei, Jeremy W. Ward, Katelyn P. Goetz, Wei Li, Marcia M. Payne, Martin Guthold, John E. Anthony, Oana D. Jurchescu Sep 2015

Quantitative Analysis Of The Density Of Trap States At The Semiconductor-Dielectric Interface In Organic Field-Effect Transistors, Peter J. Diemer, Zachary A. Lamport, Yaochuan Mei, Jeremy W. Ward, Katelyn P. Goetz, Wei Li, Marcia M. Payne, Martin Guthold, John E. Anthony, Oana D. Jurchescu

Chemistry Faculty Publications

The electrical properties of organic field-effect transistors are governed by the quality of the constituting layers, and the resulting interfaces. We compare the properties of the same organic semiconductor film, 2,8-difluoro- 5,11-bis (triethylsilylethynyl) anthradithiophene, with bottom SiO2 dielectric and top Cytop dielectric and find a 10× increase in charge carrier mobility, from 0.17 ± 0.19 cm2 V−1 s−1 to 1.5 ± 0.70 cm2 V−1 s−1, when the polymer dielectric is used. This results from a significant reduction of the trap density of states in the semiconductor band-gap, and a decrease in the …

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Enzyme Localization, Crowding, And Buffers Collectively Modulate Diffusion-Influenced Signal Transduction: Insights From Continuum Diffusion Modeling, Peter M. Kekenes-Huskey, Changsun Eun, J. A. Mccammon Sep 2015

Enzyme Localization, Crowding, And Buffers Collectively Modulate Diffusion-Influenced Signal Transduction: Insights From Continuum Diffusion Modeling, Peter M. Kekenes-Huskey, Changsun Eun, J. A. Mccammon

Chemistry Faculty Publications

Biochemical reaction networks consisting of coupled enzymes connect substrate signaling events with biological function. Substrates involved in these reactions can be strongly influenced by diffusion “barriers” arising from impenetrable cellular structures and macromolecules, as well as interactions with biomolecules, especially within crowded environments. For diffusion-influenced reactions, the spatial organization of diffusion barriers arising from intracellular structures, non-specific crowders, and specific-binders (buffers) strongly controls the temporal and spatial reaction kinetics. In this study, we use two prototypical biochemical reactions, a Goodwin oscillator, and a reaction with a periodic source/sink term to examine how a diffusion barrier that partitions substrates controls reaction …

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Eletron-Helium Laser-Assisted Free-Free Scattering For Incident Energies From 30 - 200 Ev: Effects Of Polarization Direction, B. A. Deharak, Benjamin Nosarzewski, Mahsa Siavashpouri, Nicholas L. S. Martin Sep 2015

Eletron-Helium Laser-Assisted Free-Free Scattering For Incident Energies From 30 - 200 Ev: Effects Of Polarization Direction, B. A. Deharak, Benjamin Nosarzewski, Mahsa Siavashpouri, Nicholas L. S. Martin

Physics and Astronomy Faculty Publications

We report on experiments that examine electron-helium scattering in the presence of an Nd:YAG laser field of 1.17 eV photons. At each incidentelectron energy (30, 60, and 200 eV), the laser polarization direction is varied within a plane perpendicular to the Watson approximation calculations.

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Boron-Rich Benzene And Pyrene Derivatives For The Detection Of Thermal Neutrons, Henok A. Yemam, Adam Mahl, Unsal Koldemir, Tyler Remedes, Sean Parkin, Uwe Greife, Alan Sellinger Sep 2015

Boron-Rich Benzene And Pyrene Derivatives For The Detection Of Thermal Neutrons, Henok A. Yemam, Adam Mahl, Unsal Koldemir, Tyler Remedes, Sean Parkin, Uwe Greife, Alan Sellinger

Chemistry Faculty Publications

A synthetic methodology is developed to generate boron rich aromatic small molecules based on benzene and pyrene moieties for the detection of thermal neutrons. The prepared aromatic compounds have a relatively high boron content up to 7.4 wt%, which is important for application in neutron detection as 10B (20% of natural abundance boron) has a large neutron induced reaction cross-section. This is demonstrated by preparing blends of the synthesized molecules with fluorescent dopants in poly(vinyltoluene) matrices resulting in comparable scintillation light output and neutron capture as state-of-the art commercial scintillators, but with the advantage of much lower cost. The …

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On The Brink: The Melting Of Earth’S Polar Ice Caps, Stephanie Kelley Sep 2015

On The Brink: The Melting Of Earth’S Polar Ice Caps, Stephanie Kelley

Kaleidoscope

Research indicates that earth’s polar ice caps are melting at a faster rate than ever before, a product of continued global warming. Unfortunately, side effects of this melting may negatively impact the lives of humans who dwell on this planet. Consequences may include: a significant loss of albedo, a considerable rise in sea levels, damage to aquatic ecosystems, and/or an ice age resulting from the shutdown of major oceanic currents. Although the situation is not yet imminent and the causes not yet pinpointed, the present outlook is too grim to ignore.

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Novel Human Abcc9/Sur2 Brain-Expressed Transcripts And An Eqtl Relevant To Hippocampal Sclerosis Of Aging, Peter T. Nelson, Wang-Xia Wang, Bernard R. Wilfred, Angela Wei, James Dimayuga, Qingwei Huang, Eseosa T. Ighodaro, Sergey C. Artiushin, David W. Fardo Sep 2015

Novel Human Abcc9/Sur2 Brain-Expressed Transcripts And An Eqtl Relevant To Hippocampal Sclerosis Of Aging, Peter T. Nelson, Wang-Xia Wang, Bernard R. Wilfred, Angela Wei, James Dimayuga, Qingwei Huang, Eseosa T. Ighodaro, Sergey C. Artiushin, David W. Fardo

Sanders-Brown Center on Aging Faculty Publications

ABCC9 genetic polymorphisms are associated with increased risk for various human diseases including hippocampal sclerosis of aging. The main goals of this study were 1 > to detect the ABCC9 variants and define the specific 3′ untranslated region (3′UTR) for each variant in human brain, and 2 > to determine whether a polymorphism (rs704180) associated with risk for hippocampal sclerosis of aging pathology is also associated with variation in ABCC9 transcript expression and/or splicing. Rapid amplification of ABCC9 cDNA ends (3′RACE) provided evidence of novel 3′ UTR portions of ABCC9 in human brain. In silico and experimental studies were performed focusing on …

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Expert Systems Model For Kentucky Arrow Darter Habitat In The Upper Kentucky River Basin, Benjamin L. Blandford, Michael Shouse Sep 2015

Expert Systems Model For Kentucky Arrow Darter Habitat In The Upper Kentucky River Basin, Benjamin L. Blandford, Michael Shouse

Benjamin L. Blandford

No abstract provided.

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Inelastic Neutron Scattering Cross Sections For 76Ge Relevant To Background In Neutrinoless Double-Β Decay Experiments, Benjamin P. Crider, Erin Elizabeth Peters, J. M. Allmond, Marcus T. Mcellistrem, Francisco M. Prados-Estévez, T. J. Ross, J. R. Vanhoy, Steven W. Yates Sep 2015

Inelastic Neutron Scattering Cross Sections For 76Ge Relevant To Background In Neutrinoless Double-Β Decay Experiments, Benjamin P. Crider, Erin Elizabeth Peters, J. M. Allmond, Marcus T. Mcellistrem, Francisco M. Prados-Estévez, T. J. Ross, J. R. Vanhoy, Steven W. Yates

Physics and Astronomy Faculty Publications

The experimental signature in searches for the neutrinoless double-β decay of 76Ge is a peak near 2039 keV in the spectrum. Given the low probability of the process, it is important that the background in this region be well understood. Inelastic scattering reactions with neutrons from muon-induced interactions and (α,n) reactions in the surrounding materials or in the detector can provide contributions to the background. We have measured the production cross sections for γ rays from the 76Ge(n,n'γ ) reaction in the 2039-keV region at incident neutron energies up to …

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Precision Measurement Of The Longitudinal Double-Spin Asymmetry For Inclusive Jet Production In Polarized Proton Collisions At √S=200 Gev, James K. Adkins, Renee H. Fatemi, Suvarna Ramachandran, Grant D. Webb, L. Adamczyk, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, C. D. Anson, A. Aparin, D. Arkhipkin, E. C. Aschenauer Aug 2015

Precision Measurement Of The Longitudinal Double-Spin Asymmetry For Inclusive Jet Production In Polarized Proton Collisions At √S=200 Gev, James K. Adkins, Renee H. Fatemi, Suvarna Ramachandran, Grant D. Webb, L. Adamczyk, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, C. D. Anson, A. Aparin, D. Arkhipkin, E. C. Aschenauer

Physics and Astronomy Faculty Publications

We report a new measurement of the midrapidity inclusive jet longitudinal double-spin asymmetry, ALL, in polarized pp collisions at center-of-mass energy √s=200  GeV. The STAR data place stringent constraints on polarized parton distribution functions extracted at next-to-leading order from global analyses of inclusive deep-inelastic scattering (DIS), semi-inclusive DIS, and RHIC pp data. The measured asymmetries provide evidence at the 3σ level for positive gluon polarization in the Bjorken-x region x>0.05.

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The Agricultural Footprints On The Environment, Philip Houtz Aug 2015

The Agricultural Footprints On The Environment, Philip Houtz

Kaleidoscope

Industrialized agricultural systems have given America a convenient and affordable means to supply a surplus of food products to its citizens. Transgenic technology, synthesized fertilizers, advanced pesticides, concentrated animal feeding operations (CAFOs), and the use of farm machinery have all contributed to humanity’s ability to feed the world’s rapidly growing population. However, the energy-intensive food operation of today may not be as ideal as we assume. Fossil fuels are burned to meet the energy requirements for the continual production of large quantities of fertilizer and to keep farm machines operational. Fertilizer and pesticide runoff from farmland ultimately drains into rivers …

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Sr2Ir1−XRhXO4(X<0.5): An Inhomogeneous JEff=1/2 Hubbard System, Shalinee Chikara, Daniel Haskel, Jae-Hoon Sim, Heung-Sik Kim, Cheng-Chien Chen, G. Fabbris, L. S. I. Veiga, N. M. Souza-Neto, Jsaminka Terzic, Kamal H. Butrouna, Gang Cao, Myung Joon Han, Michael Van Veenendaal Aug 2015

Sr2Ir1−XRhXO4(X<0.5): An Inhomogeneous JEff=1/2 Hubbard System, Shalinee Chikara, Daniel Haskel, Jae-Hoon Sim, Heung-Sik Kim, Cheng-Chien Chen, G. Fabbris, L. S. I. Veiga, N. M. Souza-Neto, Jsaminka Terzic, Kamal H. Butrouna, Gang Cao, Myung Joon Han, Michael Van Veenendaal

Physics and Astronomy Faculty Publications

In a combined experimental and theoretical study, we investigate the properties of Sr2Ir1−xRhxO4. From the branching ratios of the L-edge isotropic x-ray absorption spectra, we determine that the spin-orbit coupling is remarkably independent of x for both iridium and rhodium sites. DFT+U calculations show that the doping is close to isoelectronic and introduces impurity bands of predominantly rhodium character close to the lower Hubbard band. Overlap of these two bands leads to metallic behavior. Since the low-energy states for xjeff=1/2 character, we suggest that the electronic …

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Anomalous High-Energy Waterfall-Like Electronic Structure In 5 D Transition Metal Oxide Sr2Iro4 With A Strong Spin-Orbit Coupling, Yan Liu, Li Yu, Xiaowen Jia, Jianzhou Zhao, Hongming Weng, Yingying Peng, Chaoyu Chen, Zhuojin Xie, Daixiang Mou, Junfeng He, Xu Liu, Ya Feng, Hemian Yi, Lin Zhao, Guodong Liu, Shaolong He, Xiaoli Dong, Jun Zhang, Zuyan Xu, Chuangtian Chen, Gang Cao, Xi Dai, Zhong Fang, X. J. Zhou Aug 2015

Anomalous High-Energy Waterfall-Like Electronic Structure In 5 D Transition Metal Oxide Sr2Iro4 With A Strong Spin-Orbit Coupling, Yan Liu, Li Yu, Xiaowen Jia, Jianzhou Zhao, Hongming Weng, Yingying Peng, Chaoyu Chen, Zhuojin Xie, Daixiang Mou, Junfeng He, Xu Liu, Ya Feng, Hemian Yi, Lin Zhao, Guodong Liu, Shaolong He, Xiaoli Dong, Jun Zhang, Zuyan Xu, Chuangtian Chen, Gang Cao, Xi Dai, Zhong Fang, X. J. Zhou

Physics and Astronomy Faculty Publications

The low energy electronic structure of Sr2IrO4 has been well studied and understood in terms of an effective Jeff = 1/2 Mott insulator model. However, little work has been done in studying its high energy electronic behaviors. Here we report a new observation of the anomalous high energy electronic structure in Sr2IrO4. By taking high-resolution angle-resolved photoemission measurements on Sr2IrO4 over a wide energy range, we have revealed for the first time that the high energy electronic structures show unusual nearly-vertical bands that extend over a large energy range. …

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