Physics Commons^™

Analyzing The Catalytic Role Of Asp97 In The Methionine Aminopeptidase From Escherichia Coli, Sanghamitra Mitra, Kathleen M. Job, Lu Meng, Brian Bennett, Richard C. Holz

Physics Faculty Research and Publications

An active site aspartate residue, Asp97, in the methionine aminopeptidase (MetAPs) from Escherichia coli (EcMetAP-I) was mutated to alanine, glutamate, and asparagine. Asp97 is the lone carboxylate residue bound to the crystallographically determined second metal-binding site in EcMetAP-I. These mutant EcMetAP-I enzymes have been kinetically and spectroscopically characterized. Inductively coupled plasma–atomic emission spectroscopy analysis revealed that 1.0 ± 0.1 equivalents of cobalt were associated with each of the Asp97-mutated EcMetAP-Is. The effect on activity after altering Asp97 to alanine, glutamate or asparagine is, in general, due to a ∼ 9000-fold decrease in k_ca towards …

Direct Observation Of H2 Binding To A Metal Oxide Surface, J. Z. Larese, T. Arnold, L. Frazier, R. J. Hinde, A. J. Ramirez-Cuesta

Chemistry Publications and Other Works

Inelastic neutron scattering is used to probe the dynamical response of H₂ films adsorbed on MgO(100) as a function of film thickness. Concomitant diffraction measurements and a reduced-dimensionality quantum dynamical model provide insight into the molecule-surface interaction potential. At monolayer thickness, the rotational motion is strongly influenced by the surface, so that the molecules behave like quasiplanar rotors. These findings have a direct impact on understanding how molecular hydrogen binds to the surface of materials used in catalytic and storage applications.

Dynamics Of Apomyoglobin In The Α-To-Β Transition And Of Partially Unfolded Aggregated Protein, E. Fabiani, A. M. Stadler, D. Madern, M. M. Koza, M. Tehei, M. Hirai, G. Zaccai

Faculty of Science - Papers (Archive)

Changes of molecular dynamics in the α-to-β transition associated with amyloid fibril formation were explored on apo-myoglobin (ApoMb) as a model system. Circular dichroism, neutron and X-ray scattering experiments were performed as a function of temperature on the protein, at different solvent conditions. A significant change in molecular dynamics was observed at the α-to-β transition at about 55 ˚C, indicating a more resilient high temperature β structure phase. A similar effect at approximately the same temperature was observed in holo-myoglobin, associated with partial unfolding and protein aggregation. A study in a wide temperature range between 20 K and 360 K …

Homogeneous Dbd In N2: 1) Lif, Talif And Electrical Measurements, N. Gherardi, Et. Es-Sebbar, C. Sarra-Bourret, N. Naudé, F. Massines

Dr. Et-touhami Es-sebbar

In this paper we compare two different discharges that can be obtained in a DBD configuration, that is to say the filamentary discharge (usual regime in atmospheric DBD) with the Atmospheric Pressure Townsend Discharge (APTD), which is a homogeneous regime obtained in nitrogen atmosphere. The aim is to help in the understanding of the processes which control the transition from one regime to the other. To do so, the discharge is characterized through electrical measurements, coupled with optical diagnostics among which Laser Induced Fluorescence (LIF) for radical density measurements. The influence of the addition of small quantities of additives on …

Active Species Generation Of Homogeneous Dbd In N2: Experiment And Modelling, N. Gherardi, Et. Es-Sebbar, C. Sarra-Bourret, N. Naudé, F. Massines, D. Tzyganov, P. Ségur, S. Pancheshnyi

Dr. Et-touhami Es-sebbar

No abstract provided.

Linear Dichroism In Resonant Inelastic X-Ray Scattering To Molecular Spin-Orbit States, Renaud Guillemin, Stephane Carniato, Wayne C. Stolte, Loic Journel, Richard Taieb, Dennis W. Lindle, Marc Simon

Chemistry and Biochemistry Faculty Research

Polarization-dependent resonant inelastic x-ray scattering (RIXS) is shown to be a new probe of molecular-field effects on the electronic structure of isolated molecules. A combined experimental and theoretical analysis explains the linear dichroism observed in Cl 2p RIXS following Cl 1s excitation in HCl and CF₃Cl as due to molecular-field effects, including singlet-triplet exchange, indicating polarized-RIXS provides a direct probe of spin-orbit-state populations applicable to any molecule.

Inverse Velocity Dependence Of Vibrationally Promoted Electron Emission From A Metal Surface, N. H. Nahler, J. D. White, Jerry L. Larue, Daniel J. Auerbach, Alec M. Wodtke

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

All previous experimental and theoretical studies of molecular interactions at metal surfaces show that electronically nonadiabatic influences increase with molecular velocity. We report the observation of a nonadiabatic electronic effect that follows the opposite trend: The probability of electron emission from a low–work function surface—Au(111) capped by half a monolayer of Cs—increases as the velocity of the incident NO molecule decreases during collisions with highly vibrationally excited NO(X²π_½, V = 18; V is the vibrational quantum number of NO), reaching 0.1 at the lowest velocity studied. We show that these results are consistent with a vibrational …

An Extended Multireference Study Of The Electronic States Of Para-Benzyne, Carol A. Parish, Evan B. Wang, Hans Lischka

Chemistry Faculty Publications

A state-averaged, multireference complete active space (CAS) approach was used for the determination of the vertical excitation energies of valence and Rydberg states of para-benzyne. Orbitals were generated with a 10- and 32-state averaged multiconfigurational self-consistent field approach. Electron correlation was included using multireference configuration interaction with singles and doubles, including the Pople correction for size extensivity, multireference averaged quadratic coupled cluster (MR-AQCC) and MR-AQCC based on linear response theory. There is a very high density of electronic states in this diradical system—there are more than 17 states within 7 eV of the ground state including two 3s …

50th Rocky Mountain Conference On Analytical Chemistry

Rocky Mountain Conference on Magnetic Resonance

Final program, abstracts, and information about the 50th annual meeting of the Rocky Mountain Conference on Analytical Chemistry, co-endorsed by the Colorado Section of the American Chemical Society and the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Breckenridge, Colorado, July 27-31, 2008.

Surface Ion-Electron Recombination As The Main Source Of Atoms In Flowing N2 Dbd, D. Tsyganov, Et. Es-Sebbar, S. Pancheshnyi, N. Gherardi, P. Ségur, F. Massines

Dr. Et-touhami Es-sebbar

No abstract provided.

Talif Quantification Of Nitrogen Atoms Applied To Experimental Simulation Of Titan’S Atmosphere, Et. Es-Sebbar, Y. Benilan, E. Arzoumanian, M.-C. Gazeau

Dr. Et-touhami Es-sebbar

No abstract provided.

S.E.T.U.P., A New Program Of Representative Simulations Of Titan’S Atmosphere: Current Status, M-C. Gazeau, E. Arzoumanian, Y. Benilan, Et. Es-Sebbar, A. Jolly, S. Perrier, C. Romanzin

Dr. Et-touhami Es-sebbar

No abstract provided.

Comparison Of Townsend Dielectric Barrier Discharge In N2, N2/O2 And N2/N2o: Behavior And Density Of Radicals, F. Massines, Et. Es-Sebbar, N. Gherardi, N. Naudé, D. Tsyganov, P. Ségur, S. Pancheshnyi

Dr. Et-touhami Es-sebbar

No abstract provided.

Simpol.1: A Simple Group Contribution Method For Predicting Vapor Pressures And Enthalpies Of Vaporization Of Multifunctional Organic Compounds, James F. Pankow, William E. Asher

Physics Faculty Publications and Presentations

The SIMPOL.1 group contribution method is developed for predicting the liquid vapor pressure p^o_L (atm) and enthalpy of vaporization Δ H_vap (kJ mol^-1) of organic compounds as functions of temperature (T). For each compound i, the method assumes log₁₀p^o_L,i (T)=∑_kν_k,ib_k(T) where ν_k,i is the number of groups of type k, and b_k (T) is the contribution to log₁₀p^o_L,i (T) by each group of type k. A …

Real-Time Plasma Controlled Chemistry In A Two-Frequency, Confined Plasma Etcher, Vladimir Milosavljevic, Albert R. Ellingboe, Cezar Gaman, John V. Ringwood

Articles

The physics issues of developing model-based control of plasma etching are presented. A novel methodology for incorporating real-time model-based control of plasma processing systems is developed. The methodology is developed for control of two dependent variables (ion flux and chemical densities) by two independent controls (27 MHz power and O2flow). A phenomenological physics model of the nonlinear coupling between the independent controls and the dependent variables of the plasma is presented. By using a design of experiment, the functional dependencies of the response surface are determined. In conjunction with the physical model, the dependencies are used to deconvolve the sensor …

Stability And Equation Of State Of A Nanocrystalline Ga-Ge Mullite In A Vitroceramic Composite: A Synchrotron X-Ray Iffraction Study, Kristina E. Lipinska-Kalita, Patricia Kalita, Cedric Gobin, Oliver Hemmers, Thomas Hartmann, Gino Mariotto

Environmental Studies Faculty Publications

Synchrotron x-ray diffraction and diamond anvil cell techniques were used to characterize the phase transformations and to evaluate the structural stability at elevated pressures of a developed nanocrystalline composite. The optically transparent material was built of a germanium oxide-based amorphous host matrix with homogeneously dispersed 13±3 nm Ga-Ge mullite-type nanocrystals, which had a structure similar to the conventional Al₂O₃-SiO₂ mullite. The equation of state of the nanocrystals and the overall structural integrity of the nanocomposite were investigated in quasihydrostatic conditions on compression to 36 GPa and on the following decompression to ambient conditions. The overall …

Volume 01, Jessica Fields, Stephanie Neeley, Derek W. Hambright, Mary E. Lehman, Andrew R. Grzankowski, Zachary Johnson, Boone M. Prentice, Ashley M. Swandby, Victoria Morgan, Katie Williamson, Kristine G. Bender, Katelyn N. Romaine, D. Nicole Swann, Jessica Fox, Mike Mcateer, Alex Grabiec, Laura Nodtvedt, Nick Costa, Rachel Wolfe, Zack Dalton

Incite: The Journal of Undergraduate Scholarship

Introduction from Dean Dr. Charles Ross

Three Decades of Digging: Undergraduate Archeology at Longwood by Jessica Fields and Stephanie Neeley

Interactions of Allelopathy and Heat Stress in Plants by Derek W. Hambright and Mary E. Lehman

Inertial Electrostatic Confinement D-D Fusion Device: Construction and Simulation by Andrew R. Grzankowski

Shackled Nim by Zachary Johnson

Development of GC-MS and Chemometric Methods for the Analysis of Accelerants in Arson Cases by Boone M. Prentice

A Comparison of Image Analysis Methods in cDNA Microarrays by Ashley M. Swandby

Perceived Sexual Activity of Short and Long-Term Relationships by Victoria Morgan and Katie Williamson

Elderly …

Equation Of State Of Gallium Oxide To 70 Gpa: Comparison Of Quasihydrostatic And Nonhydrostatic Compression, Kristina E. Lipinska-Kalita, Patricia Kalita, Oliver Hemmers, Thomas Hartmann

Environmental Studies Faculty Publications

Synchrotron x-ray diffraction and diamond-anvil cell techniques were used to characterize pressure induced structural modifications in gallium oxide. Gallium oxide was studied on compression up to 70 GPa and on the following decompression. The effect of the pressure-transmitting medium on the structural transformations was investigated in two sets of compression and decompression runs, one with nitrogen as a quasihydrostatic pressure-transmitting medium and the other in nonhydrostatic pressure conditions. The x-ray diffraction data showed gradual phase transition from a low-density, monoclinic β-Ga₂O₃ to a high-density, rhombohedral α-Ga₂O₃. With the use of nitrogen as a …

Laboratory Experiments As Support To The Built Up Of Titan’S Theoretical Models And Interpretation Of Cassini-Huygens Data, M-C. Gazeau, Y Benilan, Et. Es-Sebbar, T. Ferradaz, E. Hébrard, A. Jolly, F. Raulin, C. Romanzin, J-C. Guillemin, C. Berteloite, A. Canosa, S. D. Le Picard, Ian R. Sims

Dr. Et-touhami Es-sebbar

No abstract provided.

The Decomposition Of Yba₂Cu₃O₇₋Δ Doped Into Ba₂Yruo₆, H. A. Blackstead, William B. Yelon, M. Kornecki, M. P. Smylie, P. J. Mcginn, Jinbo Yang, Qingsheng Cai, William Joseph James

Physics Faculty Research & Creative Works

One of the persistent criticisms of claims for observation of superconductivity in Ba2YRu1−uCuuO6 (O6) is that the diamagnetism is actually due to the decomposition of the material into YBa2Cu3O7−delta and other phases. We report a series of experiments in which YBa2Cu3O7−delta is doped into Ba2YRuO6 and carried through a series of sintering steps which were followed by magnetization, neutron diffraction, and scanning electron microscopy/microprobe measurements. It was found that the dopant YBa2Cu3O7−delta decomposed and failed to reform with cooling. It is concluded that the O6 phase is the stable high-temperature phase. The Cu released from the Y123 decomposition doped the …

Grain Growth And Texture Development In Lithium Fluoride Thin Films, Hakkwan Kim, Alexander H. King

Alexander H. King

We have studied grain-growth and texture development in polycrystalline lithium fluoride thin films using dark-field transmission electron microscopy. We demonstrate that we can isolate the size distribution of 〈111〉 surface normal grains from the overall size distribution, based on simple and plausible assumptions about the texture. The {111} texture formation and surface morphology were also observed by x-ray diffraction and atomic force microscopy, respectively. The grain-size distributions become clearly bimodal as the annealing time increases, and we deduce that the short-time size distributions are also a sum of two overlapping peaks. The smaller grain-size peak in the distribution corresponds to …

Evaluation Of Cs/Sr Waste Form For Long Term Storage And Disposal, Gary Cerefice

Waste Forms Campaign (TRP)

The goal of this project is to examine the potential long term performance of the proposed aluminosilicate waste/storage form for the isolation and eventual direct disposal of the cesium and strontium separated from recycled nuclear fuel. In the first phase of this work, researchers will investigate the sintering procedure to prepare the drum-like aluminosilicate waste/storage form from the as-received aluminosilicate powder, and then examine the basic physical properties, phase structure and microstructure of the sintered aluminosilicate with /without mixing solution with several ppm Cs/Sr. In the second phase, researchers will evaluate the interaction of the proposed waste form with structural …

A Call For A Statewide Bioinformatics Institute, John R. Rose

Journal of the South Carolina Academy of Science

No abstract provided.

A Six-Dimensional H2–H2 Potential Energy Surface For Bound State Spectroscopy, Robert Hinde

Chemistry Publications and Other Works

We present a six-dimensional potential energy surface for the (H₂)₂ dimer based on coupled-cluster electronic structure calculations employing large atom-centered Gaussian basis sets and a small set of midbond functions at the dimer’s center of mass. The surface is intended to describe accurately the bound and quasibound states of the dimers (H₂)₂, (D₂)₂, and H₂–D₂ that correlate with H₂ or D₂ monomers in the rovibrational levels (v, j) =(0,0), (0,2), (1,0), and (1,2). We employ a close-coupled approach to compute the …

Constructing Explicit Magnetic Analogies For The Dynamics Of Glass Forming Liquids, Jacob D. Stevenson, Aleksandra M. Walczak, Randall W. Hall, Peter G. Wolynes

Collected Faculty and Staff Scholarship

By defining a spatially varying replica overlap parameter for a supercooled liquid referenced to an ensemble of fiducial liquid state configurations, we explicitly construct a constrained replica free energy functional that maps directly onto an Ising Hamiltonian with both random fields and random interactions whose statistics depend on the liquid structure. Renormalization group results for random magnets when combined with these statistics for the Lennard-Jones glass suggest that discontinuous replica symmetry breaking would occur if a liquid with short range interactions could be equilibrated at a sufficiently low temperature where its mean field configurational entropy would vanish, even though the …

Modeling Of Dispersed Phase By Lagrangian Approach In Fluent - 2d Exercise, Kari Myöhänen

Kari Myöhänen

This shows an example calculation applying DPM model in Fluent. This is related to the other DPM presentation and was prepared for the course 'Theory and simulation of dispersed-phase multiphase flows" by Dr. Payman Jalali, Lappeenranta University of Technology.

Modeling Of Dispersed Phase By Lagrangian Approach In Fluent, Kari Myöhänen

Kari Myöhänen

This is a seminar work prepared for a course 'Theory and simulation of dispersed-phase multiphase flows' by Dr. Payman Jalali, Lappeenranta University of Technology

Direct Observation Of H2 Binding To A Metal Oxide Surface, J. Z. Larese, T. Arnold, L. Frazier, R. J. Hinde, A. J. Ramirez-Cuesta

Robert Hinde

Inelastic neutron scattering is used to probe the dynamical response of H₂ films adsorbed on MgO(100) as a function of film thickness. Concomitant diffraction measurements and a reduced-dimensionality quantum dynamical model provide insight into the molecule-surface interaction potential. At monolayer thickness, the rotational motion is strongly influenced by the surface, so that the molecules behave like quasiplanar rotors. These findings have a direct impact on understanding how molecular hydrogen binds to the surface of materials used in catalytic and storage applications.

Separation Of Technetium From Uranium And Waste Form Synthesis, Kenneth Czerwinski

Waste Forms Campaign (TRP)

In this project, systematic investigations on the Tc-Zr binary metal system will be evaluated for the first time. The synthesis of metallic Tc as well as its alloys with Zr will be evaluated. In order to provide valuable data to AFC R&D, the thermodynamic equilibrium phases, as well as their performance under repository conditions, will be examined.

The research objectives of this project are as follows:

• Evaluate anion exchange methods for achieving the separation of Tc from U.

• Synthesize metallic Tc from the separated product.

• Synthesize and characterize Tc alloys.

• Investigate Tc-corrosion and Tc-leaching of binary …

Dissolution, Reactor, And Environmental Behavior Of Zro2-Mgo Inert Fuel Matrix, Kenneth Czerwinski

Fuels Campaign (TRP)

This project will examine inert fuels containing ZrO₂ and MgO as the inert matrix. Ceramics with this inert matrix, Ce, U and eventually Pu will be synthesized and examined. While the Advanced Fuel Cycle Initiative focus is on inert fuels with Pu as the fissile component, this task will perform initial laboratory experiments with Ce and U. The initial work with Ce will be performed early in the project with results used as a basis for U studies. Reactor physics calculations will be used to examine suitable quantities of burnable poisons from the candidate elements Gd, Er, or Hf. …