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1

Reactant product decoupling approach to state-to-state reactive scattering H+DH  

NASA Astrophysics Data System (ADS)

A state-to-state quantum reactive scattering calculation of the prototypical H+ DH reaction in three dimensions was studied using the reactant-product decoupling (RPD) method. This reaction or its reverse reaction had been widely studied with the implementation of different kinds of methods before [J.Z.H. Zhang, W.H. Miller, J. Chem. Phys. 91 (1989) 1528; D.S. Zhang, Q.G. Zhang, Y.C. Zhang, Chin. J. Atom. Mol. Phys. 13 (1996) 93; D.M. Charutz, I. Last, M. Baer, J. Chem. Phys. 106 (1997) 7654]. The main purpose of this paper is to explore further applicability of the RPD method for use as a general and efficient computational approach to study state-to-state quantum dynamics for polyatomic reactions. In this RPD method, the full time-dependent wave function is split into the reactant component and all product components. The calculation in different arrangements can be carried out using different components of the full wave function and the corresponding Jacobi coordinates, so a substantial amount of computational effort is saved. The state-to-state results for H+ DH on the LSTH potential energy surface for J=0 are given.

Zhang, Shaolong; Tan, Zhemin; Zhang, Haiyan; Zhang, Yici; Zhang, John Z. H.

2000-05-01

2

A Chebyshev method for state-to-state reactive scattering using reactant-product decoupling: OH + H2 ? H2O + H  

NASA Astrophysics Data System (ADS)

We extend a recently developed wave packet method for computing the state-to-state quantum dynamics of AB + CD ? ABC + D reactions [M. T. Cvitaš and S. C. Althorpe, J. Phys. Chem. A 113, 4557 (2009)], 10.1021/jp8111974 to include the Chebyshev propagator. The method uses the further partitioned approach to reactant-product decoupling, which uses artificial decoupling potentials to partition the coordinate space of the reaction into separate reactant, product, and transition-state regions. Separate coordinates and basis sets can then be used that are best adapted to each region. We derive improved Chebyshev partitioning formulas which include Mandelshtam-and-Taylor-type decoupling potentials, and which are essential for the non-unitary discrete variable representations that must be used in 4-atom reactive scattering calculations. Numerical tests on the fully dimensional OH + H2 ? H2O + H reaction for J = 0 show that the new version of the method is as efficient as the previously developed split-operator version. The advantages of the Chebyshev propagator (most notably the ease of parallelization for J > 0) can now be fully exploited in state-to-state reactive scattering calculations on 4-atom reactions.

Cvitaš, Marko T.; Althorpe, Stuart C.

2013-08-01

3

Production of a Biomimetic Fe(I)-S Phase on Pyrite by Atomic-Hydrogen Beam-Surface Reactive Scattering  

PubMed Central

Molecular beam-surface scattering and X-ray absorption spectroscopic experiments were employed to study the reaction of deuterium atoms with a pyrite, FeS2 (100), surface and to investigate the electronic and geometric structures of the resulting Fe-S phases. Incident D atoms, produced by a radio frequency plasma and expanded in an effusive beam, were directed at a pyrite surface held at various temperatures from ambient up to 200 °C. During exposure to the D-atom beam, D2S products were released with a thermal distribution of molecular speeds, indicating that the D atoms likely reacted in thermal equilibrium with the surface. The yield of D2S from the surface decreased approximately exponentially with exposure duration, suggesting that the surface accessible sulfur atoms were depleted, thus leaving an iron-rich surface. This conclusion is consistent with X-ray absorption measurements of the exposed surfaces, which indicated the formation of a layered structure, with elemental iron as the outermost layer on top of a formally Fe(I)-S phase as an intermediate layer and a formally Fe(II)-S2 bulk pyrite layer at lower depths. The reduced Fe(I)-S phase is particularly remarkable because of its similarity to the catalytically active sites of small molecule metalloenzymes, such as FeFe-hydrogenases and MoFe-nitrogenases. PMID:21526811

Che, Li; Gardenghi, David J.; Szilagyi, Robert K.; Minton, Timothy K.

2011-01-01

4

Reactive Scattering of State-Selected Molecular Ions on Surfaces  

NASA Astrophysics Data System (ADS)

Experiments are described in which a beam of hyperthermal energy (5 - 100 eV) molecular ions is reactively scattered on a well-characterized surface. A variety of physical and chemical processes ensue, including energy transfer, charge transfer, dissociative scattering, and atom-abstraction reactions. The dynamics of these processes are revealed through the use of state-selected molecular projectiles. State-resolved experiments measure the relative efficacy of projectile vibrational energy versus translational energy in promoting a given reaction channel, thus indicating the type of motion associated with the reaction mechanism. A pulsed laser prepares molecular ions (NO^+, NH_3^+, or OCS^+) in a single electronic state with a selected amount of rovibrational energy. The ions are accelerated to hyperthermal energies and collide with a single-crystal surface [Ag(111), Si(111), or GaAs(110)] under ultrahigh vacuum conditions. Scattered products are detected and resolved with respect to their charge, mass, speed, and scattering angle. Experimental data and model simulations will be shown for a variety of systems.

Jacobs, Dennis C.

1997-04-01

5

Dynamics of persistent collision complexes in molecular beam reactive scattering  

Microsoft Academic Search

New microcanonical theories for the angular distributions of reactive scattering arising from long-lived collision complexes and their application to a wide range of transition state geometries are reviewed. Transition states formed at the top of centrifugal barriers on potential energy surfaces without a potential energy barrier are well described by symmetric top transition states, provided that the loosening of bending

Roger Grice

1995-01-01

6

Laser Doppler blood flowmetry multiple scattering study during reactive hyperaemia  

NASA Astrophysics Data System (ADS)

The goal of the present work is to analyse multiple scattering in laser Doppler blood flowmetry reactive hyperaemia experiments. For this purpose, three different kinds of outputs from a laser Doppler flowmeter are studied: the concentration of moving blood cells (CMBC), the linearised unfiltered flux and the unlinerised unfiltered flux. Three vascular occlusion lengths of time are observed on eight healthy volunteers. For each reactive hyperaemia experiment, the difference between the linearised unfiltered flux and the unlinearised unfiltered flux is calculated to examine the multiple scattering. The latter is considered as a function of time and compared to blood flux and concentration of erthrocyte variations. This work shows that, during reactive hyperaemia, the multiple scattering is predominant when the CMBC signal reaches its peak, the latter occurring at the peak of perfusion. However, very rapidly the multiple scattering becomes negligible whereas the CMBC and the linearised flux still take high values. Moreover, the longer the occlusion length of time, the longer the presence of the multiple scattering.

Humeau, Anne; Saumet, Jean L.; L'Huillier, Jean P.

2000-11-01

7

A quantum reactive scattering perspective on electronic nonadiabaticity  

NASA Astrophysics Data System (ADS)

Based on quantum reactive-scattering theory, we propose a method for studying the electronic nonadiabaticity in collision processes involving electron-ion rearrangements. We investigate the state-to-state transition probability for electron-ion rearrangements with two comparable approaches. In the first approach the information of the electron is only contained in the ground-state Born-Oppenheimer potential-energy surface, which is the starting point of common reactive-scattering calculations. In the second approach, the electron is explicitly taken into account and included in the calculations at the same level as the ions. Hence, the deviation in the results between the two approaches directly reflects the electronic nonadiabaticity during the collision process. To illustrate the method, we apply it to the well-known proton-transfer model of Shin and Metiu, generalized in order to allow for reactive scattering channels. We show that our explicit electron approach is able to capture electronic nonadiabaticity and the renormalization of the reaction barrier near the classical turning points of the potential in nuclear configuration space. In contrast, system properties near the equilibrium geometry of the asymptotic scattering channels are hardly affected by electronic nonadiabatic effects. We also present an analytical expression for the transition amplitude of the asymmetric proton-transfer model based on the direct evaluation of integrals over the involved Airy functions.

Peng, Yang; Ghiringhelli, Luca M.; Appel, Heiko

2014-07-01

8

Modern integral equation techniques for quantum reactive scattering theory  

SciTech Connect

Rigorous calculations of cross sections and rate constants for elementary gas phase chemical reactions are performed for comparison with experiment, to ensure that our picture of the chemical reaction is complete. We focus on the H/D+H{sub 2} {yields} H{sub 2}/DH + H reaction, and use the time independent integral equation technique in quantum reactive scattering theory. We examine the sensitivity of H+H{sub 2} state resolved integral cross sections {sigma}{sub v{prime}j{prime},vj}(E) for the transitions (v = 0,j = 0) to (v{prime} = 1,j{prime} = 1,3), to the difference between the Liu-Siegbahn-Truhlar-Horowitz (LSTH) and double many body expansion (DMBE) ab initio potential energy surfaces (PES). This sensitivity analysis is performed to determine the origin of a large discrepancy between experimental cross sections with sharply peaked energy dependence and theoretical ones with smooth energy dependence. We find that the LSTH and DMBE PESs give virtually identical cross sections, which lends credence to the theoretical energy dependence.

Auerbach, S.M.

1993-11-01

9

Modern Integral Equation Techniques for Quantum Reactive Scattering Theory.  

NASA Astrophysics Data System (ADS)

Rigorous calculations of cross sections and rate constants for elementary gas phase chemical reactions are performed for comparison with experiment, to ensure that our picture of the chemical reaction is complete. We focus on the H/D + H_2 to H _2/DH + H reaction, and use the time independent integral equation technique in quantum reactive scattering theory. We examine the sensitivity of H + H_2 state resolved integral cross sections sigma_{v^' j^ ',vj}(E) for the transitions (v = 0, j = 0) to (v^' = 1,j^ ' = 1,3), to the difference between the Liu-Siegbahn-Truhlar-Horowitz (LSTH) and double many body expansion (DMBE) ab initio potential energy surfaces (PES). This sensitivity analysis is performed to determine the origin of a large discrepancy between experimental cross sections with sharply peaked energy dependence and theoretical ones with smooth energy dependence. We find that the LSTH and DMBE PESs give virtually identical cross sections, which lends credence to the theoretical energy dependence. To facilitate quantum calculations on more complex reactive systems, we develop a new method to compute the energy Green's function with absorbing boundary conditions (ABC), for use in calculating the cumulative reaction probability. The method is an iterative technique to compute the inverse of a non-Hermitian matrix which is based on Fourier transforming time dependent dynamics, and which requires very little core memory. The Hamiltonian is evaluated in a sinc-function based discrete variable representation (DVR) which we argue may often be superior to the fast Fourier transform method for reactive scattering. We apply the resulting power series Green's function to the benchmark collinear H + H_2 system over the energy range 3.37 to 1.27 eV. The convergence of the power series is stable at all energies, and is accelerated by the use of a stronger absorbing potential. The practicality of computing the ABC-DVR Green's function in a polynomial of the Hamiltonian is discussed. We find no feasible expansion which has a fixed and small memory requirement, and is guaranteed to converge. We have found, however, that exploiting the time dependent picture of the ABC-DVR Green's function leads to a stable and efficient algorithm. The new method, which uses Newton interpolation polynomials to compute the time dependent wavefunction, gives a vastly improved version of the power series Green's function. We show that this approach is capable of obtaining converged reaction probabilities with very straightforward accuracy control. We use the ABC-DVR-Newton method to compute cross sections and rate constants for the initial state selected D + H_2(v = 1,j) to DH + H reaction. We obtain converged cross sections using no more than 4 Mbytes of core memory, and in as little CPU time as 10 minutes on a small workstation. With these cross sections, we calculate exact thermal rate constants for comparison with experiment. For the first time, quantitative agreement with experiment is obtained for the rotationally averaged rate constant k_{v=1}(T = 310 K) = 1.9 times 10^{-13} cm^3 sec^ {-1} molecule^{-1 }. The J-shifting approximation using accurate J = 0 reaction probabilities is tested against the exact results. It reliably predicts k_{v=1 }(T) for temperatures up to 700 K, but individual (v = 1, j)-selected rate constants are in error by as much as 41%.

Auerbach, Scott Michael

10

Extraction of Scattering Lengths from Production Reactions  

NASA Astrophysics Data System (ADS)

We review a method based on dispersion theory, that allows one to extract the scattering length of a hadronic two-body system from corresponding final-state interactions in production reactions. Possible theoretical uncertainties of the method are discussed. A particular case of the hyperon-nucleon final-state interaction is analyzed. A generalization of the method to the case of strangeness S = -2 and S = -3 systems is considered. The possibility to disentangle spin-triplet and spin-singlet scattering lengths by means of various polarization measurements is demonstrated by the examples of several production reactions in K-d and ?d scattering.

Gasparyan, A. M.; Haidenbauer, J.; Hanhart, C.

2011-05-01

11

Characterization of corrosion products in the permeable reactive barriers  

Microsoft Academic Search

The impact of geochemical processes and microbial activity has been a major concern for the long-term performance of reactive\\u000a iron barriers because corrosion products and precipitates during the water treatment with reactive materials will decrease\\u000a the reactivity and permeability of the iron bed. This study characterizes corrosion products in reactive iron barrier as well\\u000a as evaluates the effect of the

Y. Roh; S. Y. Lee; M. P. Elless

2000-01-01

12

Using thermally coupled reactive distillation columns in biodiesel production  

Microsoft Academic Search

Production of methyl dodecanoate (biodiesel) using lauric acid and methanol with a solid acid catalyst of sulfated zirconia is studied by using two distillation sequences. In the first sequence, the methanol recovery column follows the reactive distillation column. In the second sequence, the reactive distillation and methanol recovery columns are thermally coupled. Thermally coupled distillation sequences may consume less energy

Nghi Nguyen; Ya?ar Demirel

2011-01-01

13

Production and Consumption of Reactive Oxygen Species by Fullerenes  

EPA Science Inventory

Reactive oxygen species (ROS) are one of the most important intermediates in chemical, photochemical, and biological processes. To understand the environmental exposure and toxicity of fullerenes better, the production and consumption of ROS (singlet oxygen, superoxide, hydrogen ...

14

Entanglement of Quasielastic Scattering and Pion Production  

SciTech Connect

The extraction of neutrino oscillation parameters requires the determination of the neutrino energy from observations of the hadronic final state. Here we discuss the difficulties connected with this energy reconstruction for the ongoing experiments MiniBooNE and T2K. We point out that a lower limit to the uncertainty in the reconstructed energy from Fermi motion alone amounts to about 15%. The entanglement of very different elementary processes, in this case quasielastic scattering and pion production, in the actual observables leads to considerably larger errors. We discuss the sensitivity of the energy reconstruction to detection techniques and experimental acceptances. We also calculate the misidentification cross section for electron appearance in the T2K experiment due to neutral pion production.

Mosel, Ulrich; Lalakulich, Olga; Leitner, Tina [Institut fuer Theoretische Physik, Universitaet Giessen, D-35392 Giessen (Germany)

2011-11-23

15

Acidity-dependent reactive uptake of isoprene photooxidation products  

NASA Astrophysics Data System (ADS)

Reactive uptake of semivolatile organic compounds is considered an important formation mechanism of secondary organic material (SOM), especially for SOM from isoprene photooxidation. In the present study, an experimental setup was developed to investigate reactivate uptake of isoprene photooxidation products. Isoprene photooxidation products were continuously generated in the Harvard Environmental Chamber (HEC). The HEC was run at steady state under conditions such that the isoprene RO2 chemistry was dominated by the HO2 pathway. A sufficiently low concentration of isoprene was used to prevent particle formation in the HEC. The oxidation products were mixed with seed particles in a separate chemical reactor. Reactive uptake of gaseous species was quantified using a proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF-MS), and SOM formation was monitored using both an aerosol mass spectrometer (AMS) and a scanning mobility particle sizer (SMPS). Seed particles composed of sulfate and ammonium with a wide range of acidities were employed. Uptake of various isoprene oxidation products including hydroperoxides and epoxides exhibited very different dependence on particle acidity. The findings of the present work will be useful for developing modeling schemes for SOM formation from isoprene photooxidation products.

Liu, Y.; Kuwata, M.; McKinney, K. A.; Martin, S. T.

2013-12-01

16

Meson production in high-energy electron-nucleus scattering  

E-print Network

Experimental studies of meson production through two-photon fusion in inelastic electron-nucleus scattering is now under way. A high-energy photon radiated by the incident electron is fused with a soft photon radiated by the nucleus. The process takes place in the small-angle-Coulomb region of nuclear scattering. We expound the theory for this production process as well as its interference with coherent-radiative-meson production. In particular, we investigate the distortion of the electron wave function due to multiple-Coulomb scattering.

Göran Fäldt

2010-06-09

17

Experimental and theoretical investigations of the inelastic and reactive scattering dynamics of O(3p) + D2.  

PubMed

This paper presents a combined experimental and theoretical study of the dynamics of O((3)P) + D(2) collisions, with emphasis on a center-of-mass (c.m.) collision energy of 25 kcal mol(-1). The experiments were conducted with a crossed-molecular-beams apparatus, employing a laser detonation source to produce hyperthermal atomic oxygen and mass spectrometric detection to measure the product angular and time-of-flight distributions. The novel beam source, which enabled these experiments to be conducted, contributed unique challenges to the experiments and to the analysis, so the experimental methods and approach to the analysis are discussed in detail. Three different levels of theory were used: (1) quasiclassical trajectories (QCT), (2) time-independent quantum scattering calculations based on high-quality potential surfaces for the two lower-energy triplet states, and (3) trajectory-surface-hopping (TSH) studies that couple the triplet surfaces with the lowest singlet surface using a spin-orbit Hamiltonian derived from ab-initio calculations. The latter calculations explore the importance of intersystem crossing in the dynamics. Both experiment and theory show that inelastically scattered O atoms scatter almost exclusively in the forward direction, with little or no loss of translational energy. For the reaction, O((3)P) + D(2) --> OD + D, the experiment shows that, on average, approximately 50% of the available energy goes into product translation and that the OD product angular distributions are largely backward-peaked. These results may be interpreted in light of the QCT and TSH calculations, leading to the conclusion that the reaction occurs mainly on triplet potential energy surfaces with, at most, minor intersystem crossing to a singlet surface. Reaction on either of the two low-lying reactive triplet surfaces proceeds through a rebound mechanism in which the angular distributions are backward-peaked and the product OD is both vibrationally and rotationally excited. The quantum scattering results are in good agreement with QCT calculations, indicating that quantum effects are relatively small for this reaction at a collision energy of 25 kcal mol(-1). PMID:16435793

Garton, Donna J; Brunsvold, Amy L; Minton, Timothy K; Troya, Diego; Maiti, Biswajit; Schatz, George C

2006-02-01

18

Reactive ion etching-assisted surface-enhanced Raman scattering measurements on the single nanoparticle level  

NASA Astrophysics Data System (ADS)

Single-nanoparticle surface-enhanced Raman scattering (SERS) measurement is of essential importance for both fundamental research and practical applications. In this work, we develop a class of single-particle SERS approaches, i.e., reactive ion etching (RIE)-assisted SERS measurements correlated with scanning electron microscopy (SEM) strategy (RIE/SERS/SEM), enabling precise and high-resolution identification of single gold nanoparticle (AuNP) in facile and reliable manners. By using AuNP-coated silicon wafer and quartz glass slide as models, we further employ the developed RIE/SERS/SEM method for interrogating the relationship between SERS substrates and enhancement factor (EF) on the single particle level. Together with theoretical calculation using an established finite-difference-time-domain (FDTD) method, we demonstrate silicon wafer as superior SERS substrates, facilitating improvement of EF values.

Wang, Si-Yi; Jiang, Xiang-Xu; Xu, Ting-Ting; Wei, Xin-Pan; Lee, Shuit-Tong; He, Yao

2014-06-01

19

Treatment of the t?+D2 reaction by the methods of quantum reactive scattering  

NASA Astrophysics Data System (ADS)

We have applied the methods of quantum reactive scattering to the key resonant reaction in the muon catalyzed fusion (MCF) cycle that leads to the formation of a dt? muonic molecular ion, in which fusion takes place very rapidly. We have calculated reaction probabilities for the resonances that occur in t?+D2 scattering for incident kinetic energies less than 0.6 eV and total angular momentum Jtot=0. To reduce the six-body problem to a three-body problem, the motions of the electrons were treated in the Born-Oppenheimer (BO) approximation while those of the muon were treated with a sophisticated adiabatic approximation. The resulting three-body potential energy surface (PES) was represented by a pairwise additive approximation. The dt? part of the PES was scaled to allow it to exhibit the correct binding energy of the crucial (J,v)=(1,1) state. Scattering calculations were carried out using a hyperspherical formulation, and the positions of the resonances were found to occur at energies of a few meV greater than if dt? is assumed to be a point particle. A comparison of the resonances with the Breit-Wigner formula allowed us to calculate partial widths for back decay, ?Jtote. Once these are known for all significant Jtot, the rate of formation of dt? can be determined. This rate, next to the sticking fraction, is the most important parameter in determining the rate of the entire MCF cycle. We have also carried out a calculation whereby the muon was treated in a BO formalism and have found significant differences in the final results, demonstrating the importance of treating the muon as accurately as possible. This work represents a successful ab initio calculation of this reaction.

Zeman, V.; Armour, E. A.; Pack, R. T.

2000-05-01

20

Quantum State-Resolved Reactive and Inelastic Scattering at Gas-Liquid and Gas-Solid Interfaces  

NASA Astrophysics Data System (ADS)

Quantum state-resolved reactive and inelastic scattering at gas-liquid and gas-solid interfaces has become a research field of considerable interest in recent years. The collision and reaction dynamics of internally cold gas beams from liquid or solid surfaces is governed by two main processes, impulsive scattering (IS), where the incident particles scatter in a few-collisions environment from the surface, and trapping-desorption (TD), where full equilibration to the surface temperature (T{TD}? T{s}) occurs prior to the particles' return to the gas phase. Impulsive scattering events, on the other hand, result in significant rotational, and to a lesser extent vibrational, excitation of the scattered molecules, which can be well-described by a Boltzmann-distribution at a temperature (T{IS}>>T{s}). The quantum-state resolved detection used here allows the disentanglement of the rotational, vibrational, and translational degrees of freedom of the scattered molecules. The two examples discussed are (i) reactive scattering of monoatomic fluorine from room-temperature ionic liquids (RTILs) and (ii) inelastic scattering of benzene from a heated (˜500 K) gold surface. In the former experiment, rovibrational states of the nascent HF beam are detected using direct infrared absorption spectroscopy, and in the latter, a resonace-enhanced multi-photon-ionization (REMPI) scheme is employed in combination with a velocity-map imaging (VMI) device, which allows the detection of different vibrational states of benzene excited during the scattering process. M. E. Saecker, S. T. Govoni, D. V. Kowalski, M. E. King and G. M. Nathanson Science 252, 1421, 1991. A. M. Zolot, W. W. Harper, B. G. Perkins, P. J. Dagdigian and D. J. Nesbitt J. Chem. Phys 125, 021101, 2006. J. R. Roscioli and D. J. Nesbitt Faraday Disc. 150, 471, 2011.

Grütter, Monika; Nelson, Daniel J.; Nesbitt, David J.

2012-06-01

21

Reactive Molecular Dynamics Study of TATB Detonation Products  

NASA Astrophysics Data System (ADS)

Under shock conditions 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) reacts to form primarily gaseous N2, H2O, CO2 and CO as well as solid carbon. In a previous study of TATB thermal decomposition based on molecular dynamics (MD) simulations using the ReaxFF reactive force field, we observed a large amount of amorphous (graphite-like) carbon but no diamond structures, even at high pressures. In the current study we focus in greater detail on the reaction products mixture to assess ReaxFF predictions of both the relative stabilities of diamond-rich and graphite-rich product fluids and the equilibrium stoichiometry of CO2, CO and solid carbon at 3250 K and as a function of pressure. In these simulations, we vary systematically the initial phase of solid carbon (pure graphite vs. pure diamond), the initial oxidation state of the remaining gaseous carbon (balanced to either pure CO2 or pure CO), and the material density. In this poster we will summarize the results of these simulations, compare the results with both experimental observations and previous theoretical models, and discuss more generally the extent to which results obtained using short-time MD simulations can influence our understanding of the long-time behavior of real high explosive product mixtures.

Quenneville, Jason; Sewell, Thomas D.; Germann, Timothy C.; Shaw, M. Sam

2009-06-01

22

Prompt Photon Production in Deep Inelastic Scattering at HERA  

E-print Network

qualities and a description of current prompt photon studies. Chapter 2 extends this introduction givingPrompt Photon Production in Deep Inelastic Scattering at HERA Mairi Siobhan Bell Department May 2003 c M.S. Bell 2003 #12;Abstract First measurements of cross sections for isolated prompt photon

23

Aerosol light scattering effect on terrestrial plant productivity and energy fluxes over the eastern United States  

E-print Network

Aerosol light scattering effect on terrestrial plant productivity and energy fluxes over light scattering effect. Results show that the aerosol light scattering effect results in enhanced.5%) in 2001. These responses of plant productivity and photosynthesis to the aerosol light scattering effect

Niyogi, Dev

24

DYNAMICS OF THE REACTION OF N{sup +} WITH H{sub 2}. V. REACTIVE AND NON-REACTIVE SCATTERING OF N{sup +}({sup 3}p) AT RELATIVE ENERGIES BELOW 3.6 eV.  

SciTech Connect

We have measured product velocity vector distributions for the processes N{sup +}({sup 3}P)(H{sub 2},H)NH{sup +} and N{sup +}({sup 3}P)(H{sub 2},H{sub 2})N+ in the initial relative energy ranges of 0.98~3.60 eV and 0.66~ 2.50 eV respectively using the crossed beam technique. At energies below about 1.9 eV the predominance of a long-lived NH{sub 2}{sup +} complex is inferred from isotropic reactive scattering and a backscattered peak in the non-reactive distributions. Above 1.9 eV there is still a substantial interaction between all three atoms. The dynamics are adequately explained by a mechanism which involves accessing the deep {sup 3}B{sub 1} potential well through an avoided crossing with the {sup 3}A{sub 2} surface when the ·symmetry is relaxed from C{sub 2v} to C{sub s}. The reaction of electronically excited metastable ions, probably N{sup +}({sup 1}D), is seen as a forward peak in the reactive distributions.

Hansen, Steven G.; Farrar, James M.; Mahan, Bruce H.

1980-05-01

25

Deeply Virtual Compton Scattering and Prompt Photon production at HERA  

E-print Network

Recent results on the Deeply Virtual Compton Scattering (DVCS) and prompt photon productions from H1 and ZEUS experiments on the $ep$ collider HERA are presented. A new DVCS cross section measurements of the H1 Collaboration, for photon virtualities $Q^2>4$ GeV$^2$ and photon-proton c.m.s. energy $30production in deep inelastic scattering and photoproduction are presented both in the inclusive case and in the presence of a jet. The results are compared to NLO QCD predictions.

L. Favart

2005-10-11

26

State-to-state and state-to-all-states reactive scattering angular distributions: F+H /sub 2/. -->. HF+H  

SciTech Connect

How each state-to-state reactive transition determines nonundulatory ''state-to-all-states'' angular distribution has not yet been investigated. Here we present a complete exposure of state-to-state distorted-wave Born-approximation angular distributions in order to examine how the nonoscillatory and backward-peaked state-to-all-states reactive scattering angular distribution occurs.

Emmons, R.W.; Suck, S.H.

1983-04-01

27

Jet Production in Deep Inelastic Scattering at HERA  

E-print Network

Two-jet cross sections in deep inelastic scattering at HERA are calculated in next-to-leading order. The importance of higher order corrections and recombination scheme dependencies is studied for various jetalgorithms. Some implications for the determination of $\\alpha_s(\\mu_R^2)$, the determination of the gluon density and the associated forward jet production in the low $x$ regime at HERA are briefly discussed.

Erwin Mirkes; Dieter Zeppenfeld

1996-04-10

28

Gamma ray polarimetry. [compton scattering and pair production  

NASA Technical Reports Server (NTRS)

Spectroscopic instruments currently being proposed may possess polarimetric capabilities which sould be nurtured and enhanced to permit characterization of basic emission mechanisms which are impossible using other techniques. Compton scattering and pair production detected the polarization of high energy (E is greater than 50 keV) protons in laboratory experiments. The polarization properties of a detection system consisting of 19 germanium crystals in a closed packed array are examined and the advantages of such a detector over Thompson scattering are discussed. The possiblity of using pair production to detect polarization of high energy gamma rays, and the associated modulation factors are discussed. The central difficulty involved in using pair production polarimeters in astrophysical applications is that the typical opening of the electron or positron direction with respect to the incident photon aircitron is small, of order E/sq mc. Multiple scattering in the material used to convert the photons to an electron positron pair causes deviations in the direction of the electron and positron.

Long, K. S.; Novick, R.

1978-01-01

29

Mechanically induced generation of highly reactive excited-state oxygen molecules in cluster scattering.  

PubMed

Molecular electronic excitation in (O(2))(n) clusters induced by mechanical collisions via the "chemistry with a hammer" is investigated by a combination of molecular dynamics simulations and quantum chemistry calculations. Complete active space self-consistent field augmented with triple-zeta polarizable basis set quantum chemistry calculations of a compressed (O(2))(2) cluster model in various configurations reveal the emergence of possible pathways for the generation of electronically excited singlet O(2) molecules upon cluster compression and vibrational excitation, due to electronic curve-crossing and spin-orbit coupling. Extrapolation of the model (O(2))(2) results to larger clusters suggests a dramatic increase in the population of electronically excited O(2) products, and may account for the recently observed cluster-catalyzed oxidation of silicon surfaces, via singlet oxygen generation induced by cluster impact, followed by surface reaction of highly reactive singlet O(2) molecules. Extensive molecular dynamics simulations of (O(2))(n) clusters colliding onto a hot surface indeed reveal that cluster compression is sufficient under typical experimental conditions for nonadiabatic transitions to occur. This work highlights the importance of nonadiabatic effects in the "chemistry with a hammer." PMID:21322678

Nguyen, Tao-Nhân V; Timerghazin, Qadir K; Vach, Holger; Peslherbe, Gilles H

2011-02-14

30

Reactive Oxygen Species Production by the Spermatozoa of Patients With Idiopathic Infertility: Relationship to Seminal Plasma Antioxidants  

Microsoft Academic Search

PurposeWe attempted to determine reactive oxygen species production by the spermatozoa of patients with idiopathic infertility and healthy donors, and observe whether increased production was due to decreased seminal plasma reactive oxygen species scavengers.

Ilter Alkan; Ferruh Simsek; Goncagul Haklar; Ertan Kervancioglu; Hakan Ozveri; Suha Yalcin; Atif Akdas

1997-01-01

31

A Dependence of Hadron Production in Inelastic Muon Scattering and Dimuon Production by Protons  

E-print Network

The A dependence of the production of hadrons in inelastic muon scattering and of the production of dimuons in high $Q^2$ proton interactions are simply related. Feynman x distributions and z scaling distributions in nuclei are compared with energy loss models. Suggestions for new data analyses are presented.

S. Frankel; W. Frati

1994-10-06

32

Reactive oxygen species production by catechol stabilized copper nanoparticles  

NASA Astrophysics Data System (ADS)

Stable Cu nanoparticles (NPs) prepared using catechol containing dopamine-based linkers could generate reactive oxygen species (ROS) that can activate peroxidase enzymes and catalyze the degradation of fluorescent dye pollutants.Stable Cu nanoparticles (NPs) prepared using catechol containing dopamine-based linkers could generate reactive oxygen species (ROS) that can activate peroxidase enzymes and catalyze the degradation of fluorescent dye pollutants. Electronic supplementary information (ESI) available: Details of the synthesis of dopamine linkers and Cu NPs, peroxidase activity tests, H2O2 calibration and degradation tests for resorufin, RB and MB. See DOI: 10.1039/c3nr03563h

Chen, Cheng; Ahmed, Ishtiaq; Fruk, Ljiljana

2013-11-01

33

Diffractive D ?±(2010) production in deep inelastic scattering from ZEUS  

NASA Astrophysics Data System (ADS)

Measurements of diffractive D ?± production in deep inelastic scattering using the 1995-1997 ZEUS data are presented. Diffractive e+p ? e+XN interactions are identified by the presence of a large rapidity gap in the final state. D ?± candidates are identified from the D ? ? D ? ? D 0? decay mode, where the D0 subsequently decays either to K-?+ + (c.c.) or K-?+?-?+ (c.c.). The integrated D ?± cross section along with differential D ?± cross sections as a function of Q 2, W, x p, p T (D ?±) and ?(D ?±) have been measured in a limited kinematic region. The fraction of D ?± events produced diffractively has also been measured.

Cole, J. E.; ZEUS Collaboration

1999-10-01

34

Measurement of D*± production in deep inelastic scattering at HERA  

NASA Astrophysics Data System (ADS)

The production of D *± mesons in deep inelastic ep scattering has been measured for exchanged photon virtualities 5 < Q 2 < 1000 GeV2, using an integrated luminosity of 363 pb-1 with the ZEUS detector at HERA. Differential cross sections have been measured and compared to next-to-leading-order QCD calculations. The cross-sections are used to extract the charm contribution to the proton structure functions, expressed in terms of the reduced charm cross section, ?_{red}^{{coverline{c}}} . Theoretical calculations based on fits to inclusive HERA data are compared to the results.

Abramowicz, H.; Abt, I.; Adamczyk, L.; Adamus, M.; Aggarwal, R.; Antonelli, S.; Antonioli, P.; Antonov, A.; Arneodo, M.; Arslan, O.; Aushev, V.; Aushev, Y.; Bachynska, O.; Bamberger, A.; Barakbaev, A. N.; Barbagli, G.; Bari, G.; Barreiro, F.; Bartosik, N.; Bartsch, D.; Basile, M.; Behnke, O.; Behr, J.; Behrens, U.; Bellagamba, L.; Bertolin, A.; Bhadra, S.; Bindi, M.; Blohm, C.; Bokhonov, V.; Bold, T.; Boos, E. G.; Borras, K.; Boscherini, D.; Bot, D.; Brock, I.; Brownson, E.; Brugnera, R.; Brümmer, N.; Bruni, A.; Bruni, G.; Brzozowska, B.; Bussey, P. J.; Bylsma, B.; Caldwell, A.; Capua, M.; Carlin, R.; Catterall, C. D.; Chekanov, S.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cifarelli, L.; Cindolo, F.; Contin, A.; Cooper-Sarkar, A. M.; Coppola, N.; Corradi, M.; Corriveau, F.; Costa, M.; D'Agostini, G.; Dal Corso, F.; del Peso, J.; Dementiev, R. K.; De Pasquale, S.; Derrick, M.; Devenish, R. C. E.; Dobur, D.; Dolgoshein, B. A.; Dolinska, G.; Doyle, A. T.; Drugakov, V.; Durkin, L. S.; Dusini, S.; Eisenberg, Y.; Ermolov, P. F.; Eskreys, A.; Fang, S.; Fazio, S.; Ferrando, J.; Ferrero, M. I.; Figiel, J.; Foster, B.; Gach, G.; Galas, A.; Gallo, E.; Garfagnini, A.; Geiser, A.; Gialas, I.; Gizhko, A.; Gladilin, L. K.; Gladkov, D.; Glasman, C.; Gogota, O.; Golubkov, Yu. A.; Göttlicher, P.; Grabowska-Bold, I.; Grebenyuk, J.; Gregor, I.; Grigorescu, G.; Grzelak, G.; Gueta, O.; Guzik, M.; Gwenlan, C.; Haas, T.; Hain, W.; Hamatsu, R.; Hart, J. C.; Hartmann, H.; Hartner, G.; Hilger, E.; Hochman, D.; Hori, R.; Hüttmann, A.; Ibrahim, Z. A.; Iga, Y.; Ingbir, R.; Ishitsuka, M.; Iudin, A.; Jakob, H.-P.; Januschek, F.; Jones, T. W.; Jüngst, M.; Kadenko, I.; Kahle, B.; Kananov, S.; Kanno, T.; Karshon, U.; Karstens, F.; Katkov, I. I.; Kaur, M.; Kaur, P.; Keramidas, A.; Khein, L. A.; Kim, J. Y.; Kisielewska, D.; Kitamura, S.; Klanner, R.; Klein, U.; Koffeman, E.; Kondrashova, N.; Kononenko, O.; Kooijman, P.; Korol, Ie.; Korzhavina, I. A.; Kotanski, A.; Kötz, U.; Kovalchuk, N.; Kowalski, H.; Kuprash, O.; Kuze, M.; Lee, A.; Levchenko, B. B.; Levy, A.; Libov, V.; Limentani, S.; Ling, T. Y.; Lisovyi, M.; Lobodzinska, E.; Lohmann, W.; Löhr, B.; Lohrmann, E.; Long, K. R.; Longhin, A.; Lontkovskyi, D.; Lukina, O. Yu.; Maeda, J.; Magill, S.; Makarenko, I.; Malka, J.; Mankel, R.; Margotti, A.; Marini, G.; Martin, J. F.; Mastroberardino, A.; Mattingly, M. C. K.; Melzer-Pellmann, I.-A.; Mergelmeyer, S.; Miglioranzi, S.; Mohamad Idris, F.; Monaco, V.; Montanari, A.; Morris, J. D.; Mujkic, K.; Musgrave, B.; Nagano, K.; Namsoo, T.; Nania, R.; Nigro, A.; Ning, Y.; Nobe, T.; Notz, D.; Nowak, R. J.; Nuncio-Quiroz, A. E.; Oh, B. Y.; Okazaki, N.; Olkiewicz, K.; Onishchuk, Yu.; Papageorgiu, K.; Parenti, A.; Paul, E.; Pawlak, J. M.; Pawlik, B.; Pelfer, P. G.; Pellegrino, A.; Perlanski, W.; Perrey, H.; Piotrzkowski, K.; Plucinski, P.; Pokrovskiy, N. S.; Polini, A.; Proskuryakov, A. S.; Przybycien, M.; Raval, A.; Reeder, D. D.; Reisert, B.; Ren, Z.; Repond, J.; Ri, Y. D.; Robertson, A.; Roloff, P.; Rubinsky, I.; Ruspa, M.; Sacchi, R.; Samson, U.; Sartorelli, G.; Savin, A. A.; Saxon, D. H.; Schioppa, M.; Schlenstedt, S.; Schleper, P.; Schmidke, W. B.; Schneekloth, U.; Schönberg, V.; Schörner-Sadenius, T.; Schwartz, J.; Sciulli, F.; Shcheglova, L. M.; Shehzadi, R.; Shimizu, S.; Singh, I.; Skillicorn, I. O.; Slominski, W.; Smith, W. H.; Sola, V.; Solano, A.; Son, D.; Sosnovtsev, V.; Spiridonov, A.; Stadie, H.; Stanco, L.; Stefaniuk, N.; Stern, A.; Stewart, T. P.; Stifutkin, A.; Stopa, P.; Suchkov, S.; Susinno, G.; Suszycki, L.; Sztuk-Dambietz, J.; Szuba, D.; Szuba, J.; Tapper, A. D.; Tassi, E.; Terrón, J.; Theedt, T.; Tiecke, H.; Tokushuku, K.; Tomaszewska, J.; Trofymov, A.; Trusov, V.; Tsurugai, T.; Turcato, M.; Turkot, O.; Tymieniecka, T.; Vázquez, M.; Verbytskyi, A.; Viazlo, O.; Vlasov, N. N.; Walczak, R.; Wan Abdullah, W. A. T.; Whitmore, J. J.; Wichmann, K.; Wiggers, L.; Wing, M.; Wlasenko, M.; Wolf, G.; Wolfe, H.; Wrona, K.; Yagües-Molina, A. G.; Yamada, S.; Yamazaki, Y.; Yoshida, R.; Youngman, C.; Zakharchuk, N.; ?arnecki, A. F.; Zawiejski, L.; Zenaiev, O.; Zeuner, W.; Zhautykov, B. O.; Zhmak, N.; Zichichi, A.; Zolkapli, Z.; Zotkin, D. S.

2013-05-01

35

Reactivity impact of {sup 16}O thermal elastic-scattering nuclear data for some numerical and critical benchmark systems  

SciTech Connect

The thermal neutron-elastic-scattering cross-section data for {sup 16}O used in various modern evaluated-nuclear-data libraries were reviewed and found to be generally too high compared with the best available experimental measurements. Some of the proposed revisions to the ENDF/B-VII.0 {sup 16}O data library and recent results from the TENDL system increase this discrepancy further. The reactivity impact of revising the {sup 16}O data downward to be consistent with the best measurements was tested using the JENDL-3.3 {sup 16}O cross-section values and was found to be very small in MCNP5 simulations of the UO{sub 2} and reactor-recycle MOX-fuel cases of the ANS Doppler-defect numerical benchmark. However, large reactivity differences of up to about 14 mk (1400 pcm) were observed using {sup 16}O data files from several evaluated-nuclear-data libraries in MCNP5 simulations of the Los Alamos National Laboratory HEU heavy-water solution thermal critical experiments, which were performed in the 1950's. The latter result suggests that new measurements using HEU in a heavy-water-moderated critical facility, such as the ZED-2 zero-power reactor at the Chalk River Laboratories, might help to resolve the discrepancy between the {sup 16}O thermal elastic-scattering cross-section values and thereby reduce or better define its uncertainty, although additional assessment work would be needed to confirm this. (authors)

Kozier, K. S.; Roubtsov, D. [AECL, Chalk River Laboratories, Chalk River, ON (Canada); Plompen, A. J. M.; Kopecky, S. [EC-JRC, Inst. for Reference Materials and Measurements, Retieseweg 111, 2440 Geel (Belgium)

2012-07-01

36

CLASSIFICATION AND REACTIVITY OF SECONDARY ALUMINUM PRODUCTION WASTE  

E-print Network

APW and landfill leachate necessitates the development of a simple test that quantifies reactivity11 and dross. They are frequently disposed in dry form at Subtitle D non-5 hazardous waste landfills, where they can react adversely with liquids. Depending on the APW6 composition and landfill environment, the heat

37

Reactive Molecular Dynamics Study of TATB Detonation Products  

Microsoft Academic Search

Under shock conditions 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) reacts to form primarily gaseous N2, H2O, CO2 and CO as well as solid carbon. In a previous study of TATB thermal decomposition based on molecular dynamics (MD) simulations using the ReaxFF reactive force field, we observed a large amount of amorphous (graphite-like) carbon but no diamond structures, even at high pressures. In the current

Jason Quenneville; Thomas D. Sewell; Timothy C. Germann; M. Sam Shaw

2009-01-01

38

Azimuthal angle dependence of dijet production in unpolarized hadron scattering  

SciTech Connect

We study the azimuthal angular dependence of back-to-back dijet production in unpolarized hadron scattering H{sub A}+H{sub B}{yields}J{sub 1}+J{sub 2}+X, arising from the product of two Boer-Mulders functions, which describe the transverse spin distribution of quarks inside an unpolarized hadron. We find that when the dijet is of two identical quarks (J{sub q}+J{sub q}) or a quark-antiquark pair (J{sub q}+J{sub q}), there is a cos{delta}{phi} angular dependence of the dijet, with {delta}{phi}={phi}{sub 1}-{phi}{sub 2}, and {phi}{sub 1} and {phi}{sub 2} are the azimuthal angles of the two individual jets. In the case of J{sub q}+J{sub q} production, we find that there is a color factor enhancement in the gluonic cross section, compared with the result from the standard generalized parton model. We estimate the cos{delta}{phi} asymmetry of dijet production at RHIC, showing that the color factor enhancement in the angular dependence of J{sub q}+J{sub q} production will reverse the sign of the asymmetry.

Lu Zhun; Schmidt, Ivan [Departamento de Fisica, Universidad Tecnica Federico Santa Maria, Casilla 110-V, Valparaiso (Chile) and Center of Subatomic Physics, Valparaiso (Chile)

2008-08-01

39

Reactive Oxygen Metabolite Production Induced by Asbestos and Glass Fibers: Effect of Fiber Milling  

Microsoft Academic Search

Particle stimulated chemiluminescence (CL) production by human polymorphonuclear leucocytes (PMN) has been utilized to evaluate the pathogenicity of mineral and glass fibers with the understanding that reactive oxygen metabolites (ROM) production as measured by CL is etiopathogenically related to fiber toxicity. In the present study to investigate the specific pathogenic role of fiber number and dimensions, CL production from PMN

Toyoto IWATA; Eiji YANO

2003-01-01

40

Probing coal reactivity by time-resolved small angle x-ray scattering.  

SciTech Connect

The objective of this study is to observe changes in coal structure in situ with small angle X-ray scattering (SAXS) during solvent swelling and during pyrolysis. We have built a SAXS instrument at the Basic Energy Sciences Synchrotrons Research Center at the Advanced Photon Source that allows us to obtain scattering patterns in the millisecond time domain. The eight Argonne Premium Coal samples were used in this study. The information that can be derived from these experiments, such as changes in fractal dimensionality and in size and type of porosity, was found to be very rank-dependent. In the swelling experiments, it was noted that for certain coals, structural changes occurred in just a few minutes.

Winans, R. E.

1999-01-22

41

Viability of using calcined clays, from industrial by-products, as pozzolans of high reactivity  

Microsoft Academic Search

The present work studies the use of clays like high reactivity metakaolin, as pozzolans for concrete. This study adopted two clay types: kaolinite and kaolin by-products from the paper industry. In this second clay, besides the possible technical advantages, the ecological benefit of the use of a by-product must be considered. Initially, the chemical and mineralogical characteristics of the clays

Paulo Sérgio Lima Souza; Denise C. C. Dal Molin

2005-01-01

42

Energy evolution of the large-t elastic scattering and its correlation with multiparticle production  

SciTech Connect

It is emphasized that the collective dynamics associated with color confinement is dominating over a point-like mechanism related to a scattering of the proton constituents at the currently available values of the momentum transferred in proton elastic scattering at the LHC. Deep-elastic scattering and its role in the dissimilation of the absorptive and reflective asymptotic scattering mechanisms are discussed with emphasis on the experimental signatures associated with the multiparticle production processes.

Troshin, S. M. [Institute for High Energy Physics, Protvino, Moscow Region, 142281 (Russian Federation)

2013-04-15

43

Products of rectangular random matrices: singular values and progressive scattering.  

PubMed

We discuss the product of M rectangular random matrices with independent Gaussian entries, which have several applications, including wireless telecommunication and econophysics. For complex matrices an explicit expression for the joint probability density function is obtained using the Harish-Chandra-Itzykson-Zuber integration formula. Explicit expressions for all correlation functions and moments for finite matrix sizes are obtained using a two-matrix model and the method of biorthogonal polynomials. This generalizes the classical result for the so-called Wishart-Laguerre Gaussian unitary ensemble (or chiral unitary ensemble) at M=1, and previous results for the product of square matrices. The correlation functions are given by a determinantal point process, where the kernel can be expressed in terms of Meijer G-functions. We compare the results with numerical simulations and known results for the macroscopic level density in the limit of large matrices. The location of the end points of support for the latter are analyzed in detail for general M. Finally, we consider the so-called ergodic mutual information, which gives an upper bound for the spectral efficiency of a MIMO communication channel with multifold scattering. PMID:24329225

Akemann, Gernot; Ipsen, Jesper R; Kieburg, Mario

2013-11-01

44

Zero energy resonances in reactive scattering: anomalous temperature dependence of atom--molecule reaction rates  

NASA Astrophysics Data System (ADS)

We show that rate coefficients for inelastic processes---reactive, or nonreactive---in the (ultra)cold regime can be greatly affected by the presence of a resonance pole near E=0 in the entrance channel. This problem has been investigated previously [E. Bodo et al., J. Phys. B 37 (2004) 3641] but their analysis was restricted to the energy dependence of the reaction cross section for a particular case. Here, we present the general case, and we emphasize the possibility of a wide intermediate regime of temperatures where the rate coefficient has an anomalous temperature dependence; namely it increases as 1/T when T decreases. Eventually, the temperature dependence reverts back to the standard behavior given by Wigner's law, i.e., the rate coefficient becomes constant, but this may only be recovered at extremely low T (very deep into the ultracold regime). Thus, at least in some exceptional cases, most of the (ultra)cold regime could be dominated by this anomalous behavior.

Simbotin, I.; Ghosal, S.; Côté, R.

2010-03-01

45

Discharge-aided reactive laser ablation for ultrafine powder production  

Microsoft Academic Search

Ultrafine alumina powder was produced by aluminum target ablation with a Nd:YAG laser beam (1064 nm wavelength; 340 mJ\\/pulse energy; 7 ns pulse duration; 10 pps repetition rate), in a 120 Torr O2 atmosphere. A theoretical approach for the ablation process, based on laser energy absorption and energy balance in the target, is used for comparison with the experimental production

Ioan Chis; A. Marcu; T. Yukawa; Dumitru Dragulinescu; Constantin Grigoriu; Dana Miu; Weihua Jiang; Kiyoshi Yatsui

1998-01-01

46

A new flavonoid regulates angiogenesis and reactive oxygen species production.  

PubMed

The tumor vascular system, which is critical to the survival and growth of solid tumors, has been an attractive target for anticancer research. Building on studies that show that some flavonoids have anticancer vascular effects, we developed and analyzed the flavonoid derivative R24 [3, 6-bis (2-oxiranylmethoxy)-9H-xanthen-9-one]. A CAM assay revealed that R24 disrupted neovascular formation; fewer dendrites were detected and overall dendritic length was shorter in the R24-treated chicken embryos. The antiproliferative effect of R24 was measured by MTT assay in A549 (lung cancer), AsPC-1 (pancreatic cancer), HCT-116 (colorectal cancer), and PC-3 (prostate cancer) cell lines. R24 reduced proliferation with an IC50 of 3.44, 3.59, 1.22, and 11.83 ?M, respectively. Cell-cycle analysis and Annexin-V/propidium iodide staining showed that R24 induced apoptosis. In addition, R24 regulated intracellular ROS production in a dose-dependent manner. CM-H2DCFDA staining indicated that intracellular ROS production increased with the R24 dose. In summary, we found that R24 exhibits potent antiangiogenic and antiproliferative effects, induces apoptosis, and promotes ROS production. PMID:24729227

Zhang, Mei; Liu, Chaomei; Zhang, Zhenhuan; Yang, Shanmin; Zhang, Bingrong; Yin, Liangjie; Swarts, Steven; Vidyasagar, Sadasivan; Zhang, Lurong; Okunieff, Paul

2014-01-01

47

Drought stress and reactive oxygen species: Production, scavenging and signaling.  

PubMed

As sessile organisms, plants have evolved mechanisms that allow them to adapt and survive periods of drought stress. One of the inevitable consequences of drought stress is enhanced ROS production in the different cellular compartments, namely in the chloroplasts, the peroxisomes and the mitochondria. This enhanced ROS production is however kept under tight control by a versatile and cooperative antioxidant system that modulates intracellular ROS concentration and sets the redox-status of the cell. Furthermore, ROS enhancement under stress functions as an alarm signal that triggers acclimatory/defense responses by specific signal transduction pathways that involve H(2)O(2) as secondary messenger. ROS signaling is linked to ABA, Ca(2+) fluxes and sugar sensing and is likely to be involved both upstream and downstream of the ABA-dependent signaling pathways under drought stress. Nevertheless, if drought stress is prolonged over to a certain extent, ROS production will overwhelm the scavenging action of the anti-oxidant system resulting in extensive cellular damage and death. PMID:19513210

Cruz de Carvalho, Maria Helena

2008-03-01

48

The total virtual photoabsorption cross section, deeply virtual Compton scattering and vector-meson production  

E-print Network

Based on the two-gluon-exchange dynamical mechanism for deeply inelastic scattering at low x ~= Q^2/W^2 photoabsorption cross section, deeply virtual Compton scattering and vector-meson electroproduction. A simple expression for the cross section for deeply virtual Compton scattering is derived. Parameter-free predictions are obtained for deeply-virtual Compton forward scattering and vector-meson forward production, once the parameters in the total virtual photoabsorption cross section are determined in a fit to the experimental data on deeply inelastic scattering. Our predictions are compared with the experimental data from HERA.

Masaaki Kuroda; Dieter Schildknecht

2003-09-13

49

Diffractive Exclusive Photon Production in Deep Inelastic Scattering  

E-print Network

Predictions for deep Virtual Compton Scattering are obtained in a two-component dipole model of diffraction. The model automatically includes hard and soft components and implicitly allows for ``hadronic'' contributions via large dipoles. It is also applicable to real Compton Scattering, which provides an important constraint.

Donnachie, Alexander

2001-01-01

50

Catalytic reactive distillation process development for 1,1 diethoxy butane production from renewable sources.  

PubMed

Some acetals can be produced from renewable resources (bioalcohols) and seem to be good candidates for different applications such as oxygenated diesel additives. In the present case the production of 1,1 diethoxy butane from bioethanol and butanal is presented. Butanal can be obtained from biobutanol following a partial oxidation or a dehydrogenation process. In this paper innovative process development about the synthesis of the mentioned acetal including catalytic reactive distillation experimental and simulation results will be presented and discussed. Katapak SP modules containing Amberlyst 47 resin were used as structured catalytic packings. This reactive system allowed reaching higher conversions than the equilibrium ones at the same temperatures. All the experimental data gathered allowed to tune a simulation model for the reactive distillation operation which showed a fairly good behavior in order to perform initial 1,1 diethoxy butane production process design studies. PMID:20833537

Agirre, I; Barrio, V L; Güemez, B; Cambra, J F; Arias, P L

2011-01-01

51

Carvacrol has the priming effects of reactive oxygen species (ROS) production in C6 glioma cells  

Microsoft Academic Search

Carvacrol (5-isopropyl-2-methylphenol) is the major component of Plectranthus amboinicus. Several studies have shown that carvacrol has antibacterial, antifungal and insecticidal effects, but the mechanisms that govern these processes are unclear. Reactive oxygen species (ROS) play a major role in host defence eradication of microorganisms. In this study, we provide evidence that carvacrol has priming effects on ROS production in C6

Tzou Chi Huang; Ya Ting Lin; Kuo Pin Chuang

2010-01-01

52

Metabolic rate and reactive oxygen species production in different genotypes of GH-transgenic zebrafish  

Microsoft Academic Search

Growth hormone overexpression increases growth and consequently increases the metabolic rate in fishes. Therefore, the objective of this study was to evaluate the effects of growth hormone overexpression in zebrafish Danio rerio in terms of growth, oxygen consumption, reactive oxygen species production, lipid hydroperoxide content, antioxidant enzyme activity and glutamate-cysteine ligase catalytic subunit gene expression. The employed models were wild

C. E. Rosa; M. A. Figueiredo; C. F. C. Lanes; D. V. Almeida; J. M. Monserrat; L. F. Marins

2008-01-01

53

The production of reactive oxygen species in peripheral blood neutrophils is modulated by airway mucous  

Microsoft Academic Search

Neutrophils are a major source of reactive oxygen species (ROS). The role of airway mucous on ROS production is unknown. The\\u000a aim of our study was to investigate the direct influence of bronchoalveolar lavage fluid (BALF) and induced sputum (IS) alone\\u000a or in combination with chemical\\/biological stimulus on ROS production in peripheral blood neutrophils during chronic obstructive\\u000a pulmonary disease (COPD).

Agne Babusyte; Jolanta Jeroch; Rimantas Stakauskas; Raimundas Sakalauskas

2009-01-01

54

Analysis of a reactive extraction process for biodiesel production using a lipase immobilized on magnetic nanostructures.  

PubMed

Magnetic nanoparticles were prepared by coprecipitating Fe(2+) and Fe(3+) ions in a sodium hydroxide solution and used as support for lipase. The lipase-coated particles were applied in a reactive extraction process that allowed separation of the products formed during transesterification. Kinetics data for triolein and ethanol consumption during biodiesel (ethyl oleate) synthesis together with a thermodynamic phase equilibrium model (liquid-liquid) were used for simulation of batch and continuous processes. The analysis demonstrated the possibility of applying this biocatalytic system in the reactive zone using external magnetic fields. This approach implies new advantages in efficient location and use of lipases in column reactors for producing biodiesel. PMID:20716486

Dussan, K J; Cardona, C A; Giraldo, O H; Gutiérrez, L F; Pérez, V H

2010-12-01

55

Emission of reactive compounds and secondary products from wood-based furniture coatings  

NASA Astrophysics Data System (ADS)

Emissions of organic fragmentation products, so-called "secondary emission products" and reactive species from wood-based furniture coatings have been studied in 1 m 3 test chambers. the climatic conditions were representative of indoor environments. Relevant compounds and compound groups were the wetting agent 2,4,7,9-tetramethyl-5-dicyne-4,7-diol (T4MDD), the plasticiser di-2-ethyl-hexyl-phthalate (DEHP), aliphatic aldehydes, monoterpenes, photoinitiator fragments, acrylic monomers/reactive solvents and diisocyanate monomers. Such substances may affect human health in several ways. Aliphatic aldehydes and some photoinitiator fragments are of strong odour, while acrylates and diisocyanates cause irritation of skin, eyes and upper airways. Terpenes and reactive solvents like styrene undergo indoor chemistry in the presence of ozone, nitrogen oxides or hydroxy radicals. Secondary emission products and reactive species can achieve significant indoor concentrations. On the other hand, it has been reported that even small quantities can cause health effects. In the cases of indoor studies with special regard to emissions from furniture, chemical analysis should always include these compounds.

Salthammer, T.; Schwarz, A.; Fuhrmann, F.

56

Reactant Coordinate Based State-to-State Reactive Scattering Dynamics Implemented on Graphical Processing Units.  

PubMed

A parallel code for state-to-state quantum dynamics with propagation of time-dependent wavepacket in reactant coordinates has been developed on graphical processing units (GPUs). The propagation of wavepacket and the transformation of wavepacket from reactant to product Jacobi coordinates are entirely calculated on GPUs. A new interpolation procedure is introduced for coordinate transformation to decrease the five-loop computation to two four-loop computations. This procedure has a negligible consumption of extra GPU memory in comparison with that of the wavepacket and produces a considerable acceleration of the computational speed of the transformation. The code is tested to get differential cross sections of H+HD reaction and state-resolved reaction probabilities of O+HD for total angular momenta J = 0, 10, 20, and 30. The average speedups are 57.0 and 83.5 for the parallel computations on two C2070 and K20m GPUs relative to serial computation on Intel E5620 CPU, respectively. PMID:24940722

Zhang, Pei-Yu; Han, Ke-Li

2014-10-01

57

Evidence of phenotypic and genetic relationships between sociality, emotional reactivity and production traits in Japanese quail.  

PubMed

The social behavior of animals, which is partially controlled by genetics, is one of the factors involved in their adaptation to large breeding groups. To understand better the relationships between different social behaviors, fear behaviors and production traits, we analyzed the phenotypic and genetic correlations of these traits in Japanese quail by a second generation crossing of two lines divergently selected for their social reinstatement behavior. Analyses of results for 900 individuals showed that the phenotypic correlations between behavioral traits were low with the exception of significant correlations between sexual behavior and aggressive pecks both at phenotypic (0.51) and genetic (0.90) levels. Significant positive genetic correlations were observed between emotional reactivity toward a novel object and sexual (0.89) or aggressive (0.63) behaviors. The other genetic correlations were observed mainly between behavioral and production traits. Thus, the level of emotional reactivity, estimated by the duration of tonic immobility, was positively correlated with weight at 17 and 65 days of age (0.76 and 0.79, respectively) and with delayed egg laying onset (0.74). In contrast, a higher level of social reinstatement behavior was associated with an earlier egg laying onset (-0.71). In addition, a strong sexual motivation was correlated with an earlier laying onset (-0.68) and a higher number of eggs laid (0.82). A low level of emotional reactivity toward a novel object and also a higher aggressive behavior were genetically correlated with a higher number of eggs laid (0.61 and 0.58, respectively). These results bring new insights into the complex determinism of social and emotional reactivity behaviors in birds and their relationships with production traits. Furthermore, they highlight the need to combine animal welfare and production traits in selection programs by taking into account traits of sociability and emotional reactivity. PMID:24324761

Recoquillay, Julien; Leterrier, Christine; Calandreau, Ludovic; Bertin, Aline; Pitel, Frédérique; Gourichon, David; Vignal, Alain; Beaumont, Catherine; Le Bihan-Duval, Elisabeth; Arnould, Cécile

2013-01-01

58

Evidence of Phenotypic and Genetic Relationships between Sociality, Emotional Reactivity and Production Traits in Japanese Quail  

PubMed Central

The social behavior of animals, which is partially controlled by genetics, is one of the factors involved in their adaptation to large breeding groups. To understand better the relationships between different social behaviors, fear behaviors and production traits, we analyzed the phenotypic and genetic correlations of these traits in Japanese quail by a second generation crossing of two lines divergently selected for their social reinstatement behavior. Analyses of results for 900 individuals showed that the phenotypic correlations between behavioral traits were low with the exception of significant correlations between sexual behavior and aggressive pecks both at phenotypic (0.51) and genetic (0.90) levels. Significant positive genetic correlations were observed between emotional reactivity toward a novel object and sexual (0.89) or aggressive (0.63) behaviors. The other genetic correlations were observed mainly between behavioral and production traits. Thus, the level of emotional reactivity, estimated by the duration of tonic immobility, was positively correlated with weight at 17 and 65 days of age (0.76 and 0.79, respectively) and with delayed egg laying onset (0.74). In contrast, a higher level of social reinstatement behavior was associated with an earlier egg laying onset (-0.71). In addition, a strong sexual motivation was correlated with an earlier laying onset (-0.68) and a higher number of eggs laid (0.82). A low level of emotional reactivity toward a novel object and also a higher aggressive behavior were genetically correlated with a higher number of eggs laid (0.61 and 0.58, respectively). These results bring new insights into the complex determinism of social and emotional reactivity behaviors in birds and their relationships with production traits. Furthermore, they highlight the need to combine animal welfare and production traits in selection programs by taking into account traits of sociability and emotional reactivity. PMID:24324761

Recoquillay, Julien; Leterrier, Christine; Calandreau, Ludovic; Bertin, Aline; Pitel, Frederique; Gourichon, David; Vignal, Alain; Beaumont, Catherine; Le Bihan-Duval, Elisabeth; Arnould, Cecile

2013-01-01

59

DBI skyrmion, high energy (large s) scattering and fireball production  

Microsoft Academic Search

We analyze the high energy scattering of hadrons in QCD in an effective theory model inspired from a gravity dual description. The nucleons are skyrmion-like solutions of a DBI action, and boosted nucleons give pions field shockwaves necessary for the saturation of the Froissart bound. Nuclei are analogs of BIon crystals, with the DBI skyrmions forming a fluid with a

Horatiu Nastase

2005-01-01

60

Reactive desorption electrospray ionization for selective detection of the hydrolysis products of phosphonate esters.  

PubMed

Reactive desorption electrospray ionization (reactive DESI) is demonstrated to be a rapid and sensitive method for the direct detection of alkyl methylphosphonic acids, the hydrolysis products and metabolites of the chemical warfare (CW) agents VX (S-2-diisopropylaminoethyl-O-ethyl methylphosphonothiolate) and GB (sarin, isopropylmethyl phosphonofluoridate). Rapid and sensitive detection of these compounds is readily achieved by performing DESI from a solid surface; detection specificity is enhanced by implementation of a heterogeneous ion/molecule reaction using boric acid in the spray solvent. The reagent ion H(2)BO(3) (-) generated in the spray readily reacts with condensed-phase alkyl MPA to form anionic adducts. The specificity of this chemical reaction, together with the characteristic fragmentation patterns of the reaction products, supplies a highly discriminatory detection method for methylphosphonic acid (MPA), ethylphosphonic acid (EMPA) and isopropyl methylphosphonic acid (IMPA) in complex matrices. PMID:17607799

Song, Yishu; Cooks, R Graham

2007-08-01

61

Reactivity and stability of glucosinolates and their breakdown products in foods.  

PubMed

The chemistry of glucosinolates and their behavior during food processing is very complex. Their instability leads to the formation of a bunch of breakdown and reaction products that are very often reactive themselves. Although excessive consumption of cabbage varieties has been thought for long time to have adverse, especially goitrogenic effects, nowadays, epidemiologic studies provide data that there might be beneficial health effects as well. Especially Brassica vegetables, such as broccoli, radish, or cabbage, are rich in these interesting plant metabolites. However, information on the bioactivity of glucosinolates is only valuable when one knows which compounds are formed during processing and subsequent consumption. This review provides a comprehensive, in-depth overview on the chemical reactivity of different glucosinolates and breakdown products thereof during food preparation. PMID:25163974

Hanschen, Franziska S; Lamy, Evelyn; Schreiner, Monika; Rohn, Sascha

2014-10-20

62

Metabolic rate and reactive oxygen species production in different genotypes of GH-transgenic zebrafish.  

PubMed

Growth hormone overexpression increases growth and consequently increases the metabolic rate in fishes. Therefore, the objective of this study was to evaluate the effects of growth hormone overexpression in zebrafish Danio rerio in terms of growth, oxygen consumption, reactive oxygen species production, lipid hydroperoxide content, antioxidant enzyme activity and glutamate-cysteine ligase catalytic subunit gene expression. The employed models were wild type and transgenic (hemizygous and homozygous) zebrafish expressing the Odonthestes argentinensis growth hormone gene directed by the Cyprinus carpio beta-actin promoter. Higher growth parameters were observed in the hemizygous group. The homozygous group possessed higher oxygen consumption and reactive oxygen species production. Growth hormone transgenesis causes a decrease in glutamate-cysteine ligase catalytic subunit expression, an enzyme responsible for glutathione synthesis. Although the lipid hydroperoxide content was similar between groups, we demonstrate that growth hormone overexpression has the potential to generate oxidative stress in fishes. PMID:17931920

Rosa, C E; Figueiredo, M A; Lanes, C F C; Almeida, D V; Monserrat, J M; Marins, L F

2008-01-01

63

Analysis of the high-fructose syrup production using reactive SMB technology  

Microsoft Academic Search

This paper deals with the production of high-fructose syrup (HFS) from glucose isomerization using reactive simulated moving bed technology. The reversible reaction is catalyzed by the immobilized enzyme glucose isomerase. In a simulated moving bed reactor (SMBR), reaction and separation processes can be coupled to achieve complete reactant conversion. The isomerization kinetics is experimentally determined at 328K by the Lineweaver–Burk

Eduardo A. Borges da Silva; Antonio A. Ulson de Souza; Selene Guelli U. de Souza; Alírio E. Rodrigues

2006-01-01

64

Effect of Brazilian green propolis on the production of reactive oxygen species by stimulated neutrophils  

Microsoft Academic Search

The activity of a crude ethanol extract of green propolis and its fractions obtained by partition with hexane, chloroform and n-butanol was assessed on luminol- and lucigenin- enhanced chemiluminescence (CL) produced by rabbit neutrophils (PMNs) stimulated with particles of serum-opsonized zymosan (OZ). The total production of reactive oxygen species (ROS) by PMNs was measured by the luminol-enhanced CL (LumCL) assay

L. M. C Simões; L. E Gregório; A. A Da Silva Filho; M. L de Souza; A. E. C. S Azzolini; J. K Bastos; Y. M Lucisano-Valim

2004-01-01

65

Surface area and chemical reactivity characteristics of uranium metal corrosion products.  

SciTech Connect

The results of an initial characterization of hydride-containing corrosion products from uranium metal Zero Power Physics Reactor (ZPPR) fuel plates are presented. Sorption analyses using the BET method with a Kr adsorbate were performed to measure the specific areas of corrosion product samples. The specific surface areas of the corrosion products varied from 0.66 to 1.01 m{sup 2}/g. The reactivity of the products in Ar-9%O{sub 2} and Ar-20%O{sub 2} were measured at temperatures between 35 C and 150 C using a thermo-gravimetric analyzer. Ignition of the products occurred at temperatures of 150 C and above. The oxidation rates below ignition were comparable to rates observed for uranium metal.

Totemeier, T. C.

1998-02-17

66

The determination and analysis of site-specific rates of mitochondrial reactive oxygen species production.  

PubMed

Mitochondrial reactive oxygen species (ROS) are widely implicated in physiological and pathological pathways. We propose that it is critical to understand the specific sites of mitochondrial ROS production and their mechanisms of action. Mitochondria possess at least eight distinct sites of ROS production in the electron transport chain and matrix compartment. In this chapter, we describe the nature of the mitochondrial ROS-producing machinery and the relative capacities of each site. We provide detailed methods for the measurement of H2O2 release and the conditions under which maximal rates from each site can be achieved in intact skeletal muscle mitochondria. PMID:23791102

Quinlan, Casey L; Perevoschikova, Irina V; Goncalves, Renata L S; Hey-Mogensen, Martin; Brand, Martin D

2013-01-01

67

Catalytic reactive separation system for energy-efficient production of cumene  

DOEpatents

The present invention relates to an atmospheric pressure, reactive separation column packed with a solid acid zeolite catalyst for producing cumene from the reaction of benzene with propylene. Use of this un-pressurized column, where simultaneous reaction and partial separation occur during cumene production, allow separation of un-reacted, excess benzene from other products as they form. This high-yielding, energy-efficient system allows for one-step processing of cumene, with reduced need for product purification. Reacting propylene and benzene in the presence of beta zeolite catalysts generated a selectivity greater than 85% for catalytic separation reactions at a reaction temperature of 115 degrees C and at ambient pressure. Simultaneously, up to 76% of un-reacted benzene was separated from the product; which could be recycled back to the reactor for re-use.

Buelna, Genoveva (Nuevo Laredo, MX); Nenoff, Tina M. (Albuquerque, NM)

2009-07-28

68

Multiple-scattering model for inclusive proton production in heavy ion collisions  

NASA Technical Reports Server (NTRS)

A formalism is developed for evaluating the momentum distribution for proton production in nuclear abrasion during heavy ion collisions using the Glauber multiple-scattering series. Several models for the one-body density matrix of nuclei are considered for performing numerical calculations. Calculations for the momentum distribution of protons in abrasion are compared with experimental data for inclusive proton production.

Cucinotta, Francis A.

1994-01-01

69

Metabolism of phenol and hydroquinone to reactive products by macrophage peroxidase or purified prostaglandin H synthase  

SciTech Connect

Macrophages, an important cell-type of the bone marrow stroma, are possible targets of benzene toxicity because they contain relatively large amounts of prostaglandin H synthase (PHS), which is capable of metabolizing phenolic compounds to reactive species. PHS also catalyzes the production of prostaglandins, negative regulators of myelopoiesis. Studies indicate that the phenolic metabolites of benzene are oxidized in bone marrow to reactive products via peroxidases. With respect to macrophages, PHS peroxidase is implicated, as in vivo benzene-induced myelotoxicity is prevented by low doses of nonsteroidal anti-inflammatory agents, drugs that inhibit PHS. Incubations of either 14C-phenol or 14C-hydroquinone with a lysate of macrophages collected from mouse peritoneum (greater than 95% macrophages), resulted in an irreversible binding to protein that was dependent upon H2O2, incubation time, and concentration of radiolabel. Production of protein-bound metabolites from phenol or hydroquinone was inhibited by the peroxidase inhibitor aminotriazole. Protein binding from 14C-phenol also was inhibited by 8 microM hydroquinone, whereas binding from 14C-hydroquinone was stimulated by 5 mM phenol. The nucleophile cysteine inhibited protein binding of both phenol and hydroquinone and increased the formation of radiolabeled water-soluble metabolites. Similar to the macrophage lysate, purified PHS also catalyzed the conversion of phenol to metabolites that bound to protein and DNA; this activation was both H2O2- and arachidonic acid-dependent. These results indicate a role for macrophage peroxidase, possibly PHS peroxidase, in the conversion of phenol and hydroquinone to reactive metabolites and suggest that the macrophage should be considered when assessing the hematopoietic toxicity of benzene.

Schlosser, M.J.; Shurina, R.D.; Kalf, G.F. (Thomas Jefferson Univ., Philadelphia, PA (USA))

1989-07-01

70

VOC reactivity and its effect on ozone production during the HaChi summer campaign  

NASA Astrophysics Data System (ADS)

Measurements of ozone and its precursors conducted within the HaChi (Haze in China) project in summer 2009 were analyzed to characterize volatile organic compounds (VOCs) and their effects on ozone photochemical production at a suburban site in the North China Plain (NCP). Ozone episodes, during which running 8-h average ozone concentrations exceeding 80 ppbv lasted for more than 4 h, occurred on about two thirds of the observational days during the 5-week field campaign. This suggests continuous ozone exposure risks in this region in the summer. Average concentrations of nitrogen oxides (NOx) and VOCs are about 20 ppbv and 650 ppbC, respectively. On average, total VOC reactivity is dominated by anthropogenic VOCs. The contribution of biogenic VOCs to total ozone-forming potential, however, is also considerable in the daytime. Key species associated with ozone photochemical production are 2-butenes (18 %), isoprene (15 %), trimethylbenzenes (11 %), xylenes (8.5 %), 3-methylhexane (6 %), n-hexane (5 %) and toluene (4.5 %). Formation of ozone is found to be NOx-limited as indicated by measured VOCs/NOx ratios and further confirmed by a sensitivity study using a photochemical box model NCAR_MM. The Model simulation suggests that ozone production is also sensitive to changes in VOC reactivity under the NOx-limited regime, although this sensitivity depends strongly on how much NOx is present.

Ran, L.; Zhao, C. S.; Xu, W. Y.; Lu, X. Q.; Han, M.; Lin, W. L.; Yan, P.; Xu, X. B.; Deng, Z. Z.; Ma, N.; Liu, P. F.; Yu, J.; Liang, W. D.; Chen, L. L.

2011-05-01

71

VOC reactivity and its effect on ozone production during the HaChi summer campaign  

NASA Astrophysics Data System (ADS)

Measurements of ozone and its precursors conducted within the HaChi (Haze in China) project in summer 2009 were analyzed to characterize volatile organic compounds (VOCs) and their effects on ozone photochemical production at a suburban site in the North China Plain. Ozone episodes, during which running 8-h average ozone concentrations exceeding 80 ppbv lasted for more than 4 h, occurred on about two thirds of the observational days during the 5-week field campaign. This suggests continuous ozone exposure risks in this region during the summer. The average concentrations of nitrogen oxides (NOx) and VOCs are about 20 ppbv and 650 ppbC, respectively. Total VOC reactivity is dominated by anthropogenic VOCs, including aromatics, alkanes and most alkenes. The contribution of biogenic VOCs to total ozone-forming potential, however, is also considerable in the daytime. 2-butenes, isoprene, trimethylbenzenes, xylenes, 3-methylhexane, n-hexane and toluene are key species associated with ozone photochemical production. Formation of ozone is found to be NOx-limited as indicated by measured VOCs/NOx ratios and further confirmed by a sensitivity study using a photochemical box model NCAR_MM. The Model simulation suggests that ozone production is also sensitive to changes in VOC reactivity under the NOx-limited regime, although this sensitivity depends strongly on how much NOx is present.

Ran, L.; Zhao, C. S.; Xu, W. Y.; Lu, X. Q.; Han, M.; Lin, W. L.; Yan, P.; Xu, X. B.; Deng, Z. Z.; Ma, N.; Liu, P. F.; Yu, J.; Liang, W. D.; Chen, L. L.

2011-03-01

72

A Numerical Model for Plasma Production and Scattering from Micrometeoroids  

NASA Astrophysics Data System (ADS)

The flux of micrometeors (< 1 microgram) has long been an important unknown in the assessment of spacecraft hazards. Many efforts have been undertaken to determine the density and velocity of this population, particularly based on radar scattering using large aperture radars. Such instruments are required to produce a sufficient return from these small, though potentially overdense objects. Uncertainties remain, however, in tying the observed radar cross-sections to specific meteor parameters such as mass an density. To understand this phenomenon better, we have undertaken a theoretical and an observational campaign that is designed to determine empirically the mass flux coupled with a detailed simulation of the ablating material as the meteors disintegrate in the ionosphere. In particular, we have developed a collisional Monte Carlo simulation together with a Particle-in-Cell model to determine the self-consistent plasma profiles that occur during various stages of the meteor burn-up. We find the scaling associated with given ablation coefficients, velocities and meteoroid mass values. The implications of this work for determining meteoroid parameters empirically will be discussed.

Colestock, P. L.; Zinn, J.; Close, S.

2009-12-01

73

Detection of irradiation induced reactive oxygen species production in live cells  

NASA Astrophysics Data System (ADS)

Reactive oxygen species (ROS) is thought to play an important role in cell signaling of apoptosis, necrosis, and proliferation. Light irradiation increases mitochondrial reactive oxygen species (ROS) production and mediates its intracellular signaling by adjusting the redox potential in tumor cells. Mitochondria are the main source of ROS in the living cell. Superoxide anions (0 II - are likely the first ROS generated in the mitochondria following radiation damage, and then convert to hydrogen peroxide (H II0 II), hydroxyl radical (•OH), and singlet oxygen (10 II), etc. Conventional methods for research ROS production in mitochondria mostly use isolated mitochondria rather than mitochondria in living cells. In this study, a highly selective probe to detect mitochondrial 0 II - in live cells, MitoSOX TM Red, was applied to quantify the mitochondrial ROS production in human lung adenocarcinoma cells (ASTC-a-1) with laser scanning microscope (LSM) after ultraviolet C (UVC) and He-Ne laser irradiation. Dichiorodihydrofluoresein diacetate (DCFHDA), a common used fluorescent probe for ROS detection without specificity, were used as a comparison to image the ROS production. The fluorescent image of MItoSOX TM Red counterstained with MitoTracker Deep Red 633, a mitochondria selective probe, shows that the mitochondrial ROS production increases distinctly after UVC and He-Ne laser irradiation. DCFH-DA diffuses labeling throughout the cell though its fluorescence increases markedly too. In conclusion, the fluorescent method with MitoSOX TM Red reagent is proved to be a promising technique to research the role of ROS in radiation induced apoptosis.

Gao, Bo; Zhu, Debin

2006-09-01

74

Ischemic Preconditioning Decreases Mitochondrial Proton Leak and Reactive Oxygen Species Production in the Postischemic Heart  

PubMed Central

Background Proton leak (H+ leak) dissipates mitochondrial membrane potential (m??) through the reentry of protons into the mitochondrial matrix independent of ATP synthase. Changes in H+ leak may affect reactive oxygen species (ROS) production. We measured H+ leak and ROS production during ischemia-reperfusion and ischemic preconditioning (IPC) and examined how changing mitochondrial respiration affected m?? and ROS production. Materials/Methods Isolated rat hearts (n=6/group) were subjected to either Control-IR or IPC. Rate pressure product (RPP) was measured. Mitochondria were isolated at end reperfusion. Respiration was measured by polarography and titrated with increasing concentrations of malonate (0.5-2mM). m?? was measured using a tetraphenylphosphonium electrode. H+ leak is the respiratory rate required to maintain membrane potential at -150mV in the presence of oligomycin-A Mitochondrial complex III ROS production was measured by fluorometry using Amplex-Red. Results IPC improved recovery of RPP at end reperfusion (63±4% vs. 21±2% in Control-IR, p<0.05). Ischemia-reperfusion caused increased H+ leak (94±12 vs. 31±1 nanomoles O/mg protein/min in Non-Ischemic Control, p<0.05). IPC attenuates these increases (55±9 nanomoles O/mg protein/min, p< 0.05 vs. Control-IR). IPC reduced mitochondrial ROS production compared to Control-IR (31±2 vs. 40±3 nanomoles/mg protein/min, p<0.05). As mitochondrial respiration decreased, m?? and mitochondrial ROS production also decreased. ROS production remained lower in IPC than in Control-IR for all m?? and respiration rates. Conclusions Increasing H+ leak is not associated with increased ROS production. IPC decreases both the magnitude of H+ leak and ROS production after ischemia-reperfusion. PMID:21035133

Quarrie, Ricardo; Cramer, Brandon M.; Lee, Daniel S.; Steinbaugh, Gregory E.; Erdahl, Warren; Pfeiffer, Douglas R.; Zweier, Jay L.; Crestanello, Juan A.

2010-01-01

75

Ozone production and reactive nitrogen chemistry during the 2008 Beijing Olympic Games  

NASA Astrophysics Data System (ADS)

Measurements of ozone, peroxyacetyl nitrate (PAN), and related pollutants (NOx, NOy, NMHCs, and carbonyls) were conducted at an urban/suburban site in Beijing before, during, and after the 2008 Beijing Olympics. The data are analyzed to examine their responses to the strict pollution control measures in Beijing and to gain insight into ozone-precursor photochemistry and reactive nitrogen speciation. Approximately 40% of the study days had ozone pollution with the maximum hourly ozone concentration exceeding 100 ppbv. The pollution levels were relatively low during the Games (Aug 8th - 24th), mainly due to weather conditions (rainfalls and northerly winds). Elevated levels of PAN were frequently observed with a peak concentration of up to 9.34 ppbv and a PAN/O3 ratio of 0.055 ppbv/ppbv. Ozone production efficiencies (OPE) derived from the correlation of O3/Ox versus NOz were in the range of 2-5 ppbv/ppbv. The results suggested a VOCs-limited regime for ozone production. PAN accounted for a relatively high fraction (20 - 40%) of NOz during photochemical episodes. The sources of reactive nitrogen are discussed in relation to wind flow and to other air pollutants.

Xue, L.; Wang, T.; Gao, J.; Wang, X.; Gao, X.; Nie, W.; Ding, A.; Zhang, Q.; Wang, W.

2009-12-01

76

Spin Biochemistry Modulates Reactive Oxygen Species (ROS) Production by Radio Frequency Magnetic Fields  

PubMed Central

The effects of weak magnetic fields on the biological production of reactive oxygen species (ROS) from intracellular superoxide (O2•?) and extracellular hydrogen peroxide (H2O2) were investigated in vitro with rat pulmonary arterial smooth muscle cells (rPASMC). A decrease in O2•? and an increase in H2O2 concentrations were observed in the presence of a 7 MHz radio frequency (RF) at 10 ?TRMS and static 45 ?T magnetic fields. We propose that O2•? and H2O2 production in some metabolic processes occur through singlet-triplet modulation of semiquinone flavin (FADH•) enzymes and O2•? spin-correlated radical pairs. Spin-radical pair products are modulated by the 7 MHz RF magnetic fields that presumably decouple flavin hyperfine interactions during spin coherence. RF flavin hyperfine decoupling results in an increase of H2O2 singlet state products, which creates cellular oxidative stress and acts as a secondary messenger that affects cellular proliferation. This study demonstrates the interplay between O2•? and H2O2 production when influenced by RF magnetic fields and underscores the subtle effects of low-frequency magnetic fields on oxidative metabolism, ROS signaling, and cellular growth. PMID:24681944

Usselman, Robert J.; Hill, Iain; Singel, David J.; Martino, Carlos F.

2014-01-01

77

Reactive Oxygen Species Production in Peripheral Blood Neutrophils of Obstructive Sleep Apnea Patients  

PubMed Central

Obstructive sleep apnea (OSA) as well as obesity is associated with increased production of reactive oxygen species (ROS). Neutrophils produce great amounts of ROS. The aim was to evaluate peripheral blood neutrophils ROS production in men with OSA and to establish relations with disease severity and obesity. Methods. Forty-six men with OSA and 10 controls were investigated. OSA was confirmed by polysomnography (PSG), when apnea/hypopnea index was >5/h. Body mass index (BMI) was evaluated. Neutrophils were isolated from peripheral blood in the morning after PSG. Dihydrorhodamine-123 was used for ROS detection. Data is presented as median (25th and 75th percentiles). All subjects were divided into four groups: nonobese mild-to-moderate OSA, obese mild-to-moderate OSA, nonobese severe OSA, and obese severe OSA. Results. Neutrophil ROS production was higher in nonobese severe OSA group compared to nonobese mild-to-moderate OSA (mean fluorescence intensity (MFI) 213.4 (89.0–238.9) versus 44.5 (20.5–58.4), P < 0.05). In obese patient groups, ROS production was more increased in severe OSA compared to mild-to-moderate OSA group (MFI 74.5 (47.9–182.4) versus 31.0 (14.8–53.8), P < 0.05). It did not differ in the groups with different BMI and the same severity of OSA. Conclusion. Increased neutrophil ROS production was related to more severe OSA but not obesity. PMID:23766689

Miliauskas, Skaidrius; Sakalauskas, Raimundas

2013-01-01

78

Reactive scattering of H2 from Cu(100): comparison of dynamics calculations based on the specific reaction parameter approach to density functional theory with experiment.  

PubMed

We present new experimental and theoretical results for reactive scattering of dihydrogen from Cu(100). In the new experiments, the associative desorption of H(2) is studied in a velocity resolved and final rovibrational state selected manner, using time-of-flight techniques in combination with resonance-enhanced multi-photon ionization laser detection. Average desorption energies and rotational quadrupole alignment parameters were obtained in this way for a number of (v = 0, 1) rotational states, v being the vibrational quantum number. Results of quantum dynamics calculations based on a potential energy surface computed with a specific reaction parameter (SRP) density functional, which was derived earlier for dihydrogen interacting with Cu(111), are compared with the results of the new experiments and with the results of previous molecular beam experiments on sticking of H(2) and on rovibrationally elastic and inelastic scattering of H(2) and D(2) from Cu(100). The calculations use the Born-Oppenheimer and static surface approximations. With the functional derived semi-empirically for dihydrogen + Cu(111), a chemically accurate description is obtained of the molecular beam experiments on sticking of H(2) on Cu(100), and a highly accurate description is obtained of rovibrationally elastic and inelastic scattering of D(2) from Cu(100) and of the orientational dependence of the reaction of (v = 1, j = 2 - 4) H(2) on Cu(100). This suggests that a SRP density functional derived for H(2) interacting with a specific low index face of a metal will yield accurate results for H(2) reactively scattering from another low index face of the same metal, and that it may also yield accurate results for H(2) interacting with a defected (e.g., stepped) surface of that same metal, in a system of catalytic interest. However, the description that was obtained of the average desorption energies, of rovibrationally elastic and inelastic scattering of H(2) from Cu(100), and of the orientational dependence of reaction of (v = 0, j = 3 - 5, 8) H(2) on Cu(100) compares less well with the available experiments. More research is needed to establish whether more accurate SRP-density functional theory dynamics results can be obtained for these observables if surface atom motion is added to the dynamical model. The experimentally and theoretically found dependence of the rotational quadrupole alignment parameter on the rotational quantum number provides evidence for rotational enhancement of reaction at low translational energies. PMID:23387616

Sementa, L; Wijzenbroek, M; van Kolck, B J; Somers, M F; Al-Halabi, A; Busnengo, H F; Olsen, R A; Kroes, G J; Rutkowski, M; Thewes, C; Kleimeier, N F; Zacharias, H

2013-01-28

79

Muon production in low-energy electron-nucleon and electron-nucleus scattering  

E-print Network

Recently, muon production in electron-proton scattering has been suggested as a possible candidate reaction for the identification of lepton-flavor violation due to physics beyond the Standard Model. Here we point out that the Standard-Model processes $e^- p \\to \\mu^- p \\bar{\

Prashanth Jaikumar; Daniel R. Phillips; Lucas Platter; Madappa Prakash

2007-07-20

80

Measurement of D + and Lambda c + production in deep inelastic scattering at HERA  

Microsoft Academic Search

Charm production in deep inelastic scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 120 pb-1. The hadronic decay channels D + --> K S 0 pi +, Lambda c + --> pK S 0 and Lambda c + --> Lambda pi +, and their charge conjugates, were reconstructed. The presence of a neutral

H. Abramowicz; I. Abt; L. Adamczyk; M. Adamus; R. Aggarwal; S. Antonelli; P. Antonioli; A. Antonov; M. Arneodo; V. Aushev; Y. Aushev; O. Bachynska; A. Bamberger; A. N. Barakbaev; G. Barbagli; G. Bari; F. Barreiro; D. Bartsch; M. Basile; O. Behnke; J. Behr; U. Behrens; L. Bellagamba; A. Bertolin; S. Bhadra; M. Bindi; C. Blohm; T. Bold; E. G. Boos; M. Borodin; K. Borras; D. Boscherini; D. Bot; S. K. Boutle; I. Brock; E. Brownson; R. Brugnera; N. Brümmer; A. Bruni; G. Bruni; B. Brzozowska; P. J. Bussey; J. M. Butterworth; B. Bylsma; A. Caldwell; M. Capua; R. Carlin; C. D. Catterall; S. Chekanov; J. Chwastowski; J. Ciborowski; R. Ciesielski; L. Cifarelli; F. Cindolo; A. Contin; A. M. Cooper-Sarkar; N. Coppola; M. Corradi; F. Corriveau; M. Costa; G. D'Agostini; F. Dal Corso; J. de Favereau; J. Del Peso; R. K. Dementiev; S. de Pasquale; M. Derrick; R. C. E. Devenish; D. Dobur; B. A. Dolgoshein; A. T. Doyle; V. Drugakov; L. S. Durkin; S. Dusini; Y. Eisenberg; P. F. Ermolov; A. Eskreys; S. Fang; S. Fazio; J. Ferrando; M. I. Ferrero; J. Figiel; M. Forrest; B. Foster; S. Fourletov; G. Gach; A. Galas; E. Gallo; A. Garfagnini; A. Geiser; I. Gialas; L. K. Gladilin; D. Gladkov; C. Glasman; O. Gogota; Yu. A. Golubkov; P. Göttlicher; I. Grabowska-Bold; J. Grebenyuk; I. Gregor; G. Grigorescu; G. Grzelak; C. Gwenlan; T. Haas; W. Hain; R. Hamatsu; J. C. Hart; H. Hartmann; G. Hartner; E. Hilger; D. Hochman; U. Holm; R. Hori; K. Horton; A. Hüttmann; G. Iacobucci; Z. A. Ibrahim; Y. Iga; R. Ingbir; M. Ishitsuka; H.-P. Jakob; F. Januschek; M. Jimenez; T. W. Jones; M. Jüngst; I. Kadenko; B. Kahle; B. Kamaluddin; S. Kananov; T. Kanno; U. Karshon; F. Karstens; I. I. Katkov; M. Kaur; P. Kaur; A. Keramidas; L. A. Khein; J. Y. Kim; D. Kisielewska; S. Kitamura; R. Klanner; U. Klein; E. Koffeman; D. Kollar; P. Kooijman; Ie. Korol; I. A. Korzhavina; A. Kotanski; U. Kötz; H. Kowalski; P. Kulinski; O. Kuprash; M. Kuze; A. Lee; B. B. Levchenko; A. Levy; V. Libov; S. Limentani; T. Y. Ling; M. Lisovyi; E. Lobodzinska; W. Lohmann; B. Löhr; E. Lohrmann; J. H. Loizides; K. R. Long; A. Longhin; D. Lontkovskyi; O. Yu. Lukina; P. Luzniak; J. Maeda; S. Magill; I. Makarenko; J. Malka; R. Mankel; A. Margotti; G. Marini; J. F. Martin; A. Mastroberardino; T. Matsumoto; M. C. K. Mattingly; I.-A. Melzer-Pellmann; S. Miglioranzi; F. Mohamad Idris; V. Monaco; A. Montanari; J. D. Morris; B. Musgrave; K. Nagano; T. Namsoo; R. Nania; D. Nicholass; A. Nigro; Y. Ning; U. Noor; D. Notz; R. J. Nowak; A. E. Nuncio-Quiroz; B. Y. Oh; N. Okazaki; K. Oliver; K. Olkiewicz; Yu. Onishchuk; O. Ota; K. Papageorgiu; A. Parenti; E. Paul; J. M. Pawlak; B. Pawlik; P. G. Pelfer; A. Pellegrino; W. Perlanski; H. Perrey; K. Piotrzkowski; P. Plucinski; N. S. Pokrovskiy; A. Polini; A. S. P Roskuryakov; M. Przybycien; A. Raval; D. D. Reeder; B. Reisert; Z. Ren; J. Repond; Y. D. Ri; A. Robertson; P. Roloff; E. Ron; I. Rubinsky; M. Ruspa; R. Sacchi; A. Salii; U. Samson; G. Sartorelli; A. A. Savin; D. H. Saxon; M. Schioppa; S. Schlenstedt; P. Schleper; W. B. Schmidke; U. Schneekloth; V. Schönberg; T. Schörner-Sadenius; J. Schwartz; F. Sciulli; L. M. Shcheglova; R. Shehzadi; S. Shimizu; I. Singh; I. O. Skillicorn; W. Slominski; W. H. Smith; V. Sola; A. Solano; D. Son; V. Sosnovtsev; A. Spiridonov; H. Stadie; L. Stanco; A. Stern; T. P. Stewart; A. Stifutkin; P. Stopa; S. Suchkov; G. Susinno; L. Suszycki; J. Sztuk; D. Szuba; J. Szuba; A. D. Tapper; E. Tassi; J. Terrón; T. Theedt; H. Tiecke; K. Tokushuku; O. Tomalak; J. Tomaszewska; T. Tsurugai; M. Turcato; T. Tymieniecka; C. Uribe-Estrada; M. Vázquez; A. Verbytskyi; O. Viazlo; N. N. Vlasov; O. Volynets; R. Walczak; W. A. T. Wan Abdullah; J. J. Whitmore; J. Whyte; L. Wiggers; M. Wing; M. Wlasenko; G. Wolf; H. Wolfe; K. Wrona; A. A. Yagües-Molina; S. Yamada; Y. Yamazaki; R. Yoshida; C. Youngman; A. A. Zarnecki; L. Zawiejski; O. Zenaiev; W. Zeuner; B. O. Zhautykov; N. Zhmak; C. Zhou; A. Zichichi; M. Zolko; D. S. Zotkin; Z. Zulkapli

2010-01-01

81

Atopy, Cytokine Production, and Airway Reactivity as Predictors of Pre-School Asthma and Airway Responsiveness  

PubMed Central

Summary Background Childhood asthma is often characterized by recurrent wheezing, airway hyper-reactivity, atopy, and altered immune characteristics; however, our understanding of the development of these relationships from early in life remains unclear. The aim of our study was to evaluate whether atopy, cytokine production by peripheral blood mononuclear cells (PBMCs), and airway responsiveness, assessed in infants and toddlers, are associated with asthma and airway responsiveness at 4-years of age. Methods Infants with eczema (N = 116), enrolled prior to wheezing, were assessed at entry (mean age of 10.7 months), at 1-year follow-up (N = 112), and at 4-years of age (N = 94). Total serum IgE, specific IgE to allergens, and cytokines produced by stimulated PBMCs, were assessed at entry and 1-year follow-up. Spirometry was obtained at all 3-visits, while airway reactivity to methacholine was assessed at entry and 1-year follow-up, and bronchodilator (BD) responsiveness, as well as current asthma was assessed at 4-years of age. Results We found that pre-school children with asthma had lower spirometry and a greater BD-response. Serum IgE, particularly to egg and/or milk, and altered cytokine production by PBMCs at entry to the study were associated with asthma, lower spirometry, and greater airway responsiveness at 4-years of age. In addition, we found that airway responsiveness, as well as spirometry, tracked from infancy to 4-years of age. Conclusions While spirometry and airway responsiveness track longitudinally from early in life, atopy and cytokine production by PBMCs are associated not only with an increased risk of pre-school asthma, but also lower spirometry and increased airway responsiveness. PMID:23401409

Sarria, Edgar E.; Mattiello, Rita; Yao, Weiguo; Chakr, Valentina; Tiller, Christina J.; Kisling, Jeffrey; Tabbey, Rebeka; Yu, Zhangsheng; Kaplan, Mark H.; Tepper, Robert S.

2014-01-01

82

The essential oil of bergamot stimulates reactive oxygen species production in human polymorphonuclear leukocytes.  

PubMed

Bergamot (Citrus aurantium L. subsp. bergamia) essential oil (BEO) is used in folk medicine as an antiseptic and anthelminthic and to facilitate wound healing. Evidence indicates that BEO has substantial antimicrobial activity; however its effects on immunity have never been examined. We studied the effects of BEO on reactive oxygen species (ROS) production in human polymorphonuclear leukocytes (PMN) and the role of Ca(2+) in the functional responses evoked by BEO in these cells. Results show that BEO increased intracellular ROS production in human PMN, an effect that required the contribution of extracellular (and, to a lesser extent, of intracellular) Ca(2+) . Bergamot essential oil also significantly increased ROS production induced by the chemotactic peptide N-formyl-Met-Leu-Phe and reduced the response to the protein kinase C activator phorbol myristate acetate. In conclusion, this is the first report showing the ability of BEO to increase ROS production in human PMN. This effect could both contribute to the activity of BEO in infections and in tissue healing as well as underlie an intrinsic proinflammatory potential. The relevance of these findings for the clinical uses of BEO needs careful consideration. PMID:24458921

Cosentino, Marco; Luini, Alessandra; Bombelli, Raffaella; Corasaniti, Maria T; Bagetta, Giacinto; Marino, Franca

2014-08-01

83

The effect of electromagnetic field on reactive oxygen species production in human neutrophils in vitro.  

PubMed

The present study was undertaken in order to determine the effect of low frequency electromagnetic field (EMF) on reactive oxygen species (ROS) production in human neutrophils in peripheral blood in vitro. We investigated how differently generated EMF and several levels of magnetic induction affect ROS production. To evaluate the level of ROS production, two fluorescent dyes were used: 2'7'-dichlorofluorscein-diacetate and dihydrorhodamine. Phorbol 12-myristate 13-acetate (PMA), known as strong stimulator of the respiratory burst, was also used. Alternating magnetic field was generated by means of Viofor JPS apparatus. Three different levels of magnetic induction have been analyzed (10, 40 and 60 ?T). Fluorescence of dichlorofluorescein and 123 rhodamine was measured by flow cytometry. The experiments demonstrated that only EMF tuned to the calcium ion cyclotron resonance frequency was able to affect ROS production in neutrophils. Statistical analysis showed that this effect depended on magnetic induction value of applied EMF. Incubation in EMF inhibited cell activity slightly in unstimulated neutrophils, whereas the activity of PMA-stimulated neutrophils has increased after incubation in EMF. PMID:23137127

Poniedzialek, Barbara; Rzymski, Piotr; Nawrocka-Bogusz, Honorata; Jaroszyk, Feliks; Wiktorowicz, Krzysztof

2013-09-01

84

Oxygen Pathway Modeling Estimates High Reactive Oxygen Species Production above the Highest Permanent Human Habitation  

PubMed Central

The production of reactive oxygen species (ROS) from the inner mitochondrial membrane is one of many fundamental processes governing the balance between health and disease. It is well known that ROS are necessary signaling molecules in gene expression, yet when expressed at high levels, ROS may cause oxidative stress and cell damage. Both hypoxia and hyperoxia may alter ROS production by changing mitochondrial Po2 (). Because depends on the balance between O2 transport and utilization, we formulated an integrative mathematical model of O2 transport and utilization in skeletal muscle to predict conditions to cause abnormally high ROS generation. Simulations using data from healthy subjects during maximal exercise at sea level reveal little mitochondrial ROS production. However, altitude triggers high mitochondrial ROS production in muscle regions with high metabolic capacity but limited O2 delivery. This altitude roughly coincides with the highest location of permanent human habitation. Above 25,000 ft., more than 90% of exercising muscle is predicted to produce abnormally high levels of ROS, corresponding to the “death zone” in mountaineering. PMID:25375931

Cano, Isaac; Selivanov, Vitaly; Gomez-Cabrero, David; Tegner, Jesper; Roca, Josep; Wagner, Peter D.; Cascante, Marta

2014-01-01

85

Multistate reactivity in styrene epoxidation by compound I of cytochrome p450: mechanisms of products and side products formation.  

PubMed

Density functional theoretical calculations are used to elucidate the epoxidation mechanism of styrene with a cytochrome P450 model Compound I, and the formation of side products. The reaction features multistate reactivity (MSR) with different spin states (doublet and quartet) and different electromeric situations having carbon radicals and cations, as well as iron(III) and iron(IV) oxidation states. The mechanisms involve state-specific product formation, as follows: a) The low-spin pathways lead to epoxide formation in effectively concerted mechanisms. b) The high-spin pathways have finite barriers for ring-closure and may have a sufficiently long lifetime to undergo rearrangement and lead to side products. c) The high-spin radical intermediate, (4)2(rad)-IV, has a ring closure barrier as small as the C--C rotation barrier. This intermediate will therefore lose stereochemistry and lead to a mixture of cis and trans epoxides. The barriers for the production of aldehyde and suicidal complexes are too high for this intermediate. d) The high-spin radical intermediate, (4)2(rad)-III, has a substantial ring closure barrier and may survive long enough time to lead to suicidal, phenacetaldehyde and 2-hydroxostyrene side products. e) The phenacetaldehyde and 2-hydroxostyrene products both originate from crossover from the (4)2(rad)-III radical intermediate to the cationic state, (4)2(cat,z(2) ). The process involves an N-protonated porphyrin intermediate that re-shuttles the proton back to the substrate to form either phenacetaldehyde or 2-hydroxostyrene products. This resembles the internally mediated NIH-shift observed during benzene hydroxylation. PMID:15744771

Kumar, Devesh; de Visser, Sam P; Shaik, Sason

2005-04-22

86

Imaging the proton via hard exclusive production in diffractive pp scattering  

SciTech Connect

We discuss the prospects for probing Generalized Parton Distributions (GPDs) via exclusive production of a high-mass system (H = heavy quarkonium, di-photon, di-jet, Higgs boson) in diffractive pp scattering, pp -> p + H + p. In such processes the interplay of hard and soft interactions gives rise to a diffraction pattern in the final-state proton transverse momenta, which is sensitive to the transverse spatial distribution of partons in the colliding protons. We comment on the plans for diffractive pp measurements at RHIC and LHC. Such studies could complement future measurements of GPDs in hard exclusive ep scattering (JLab, COMPASS, EIC).

Charles Hyde; Leonid Frankfurt; Mark Strikman; Christian Weiss

2007-05-21

87

Diffractive Production of Jets and Weak Bosons, and Tests of Hard-Scattering Factorization  

E-print Network

We extract diffractive parton densities from data on diffractive deep inelastic scattering (DIS) and on diffractive photoproduction of jets. We explore the results of several ansaetze for the functional form of the parton densities. Then we use the fitted parton densities to predict the diffractive production of jets and of W's and Z's in p-pbar collisions at the Tevatron. To fit the photoproduction data requires a large gluon density in the Pomeron. The predictions for the Tevatron cross sections are substantially higher than data; this signals a breakdown of hard-scattering factorization in diffractive hadron-hadron collisions.

Lyndon Alvero; John C. Collins; Juan Terron; Jim Whitmore

1998-05-08

88

Superoxide production and reactive oxygen species signaling by endothelial nitric-oxide synthase.  

PubMed

Reactive oxygen species can function as intracellular messengers, but linking these signaling events with specific enzymes has been difficult. Purified endothelial nitric-oxide synthase (eNOS) can generate superoxide (O(2)) under special conditions but is only known to participate in cell signaling through NO. Here we show that eNOS regulates tumor necrosis factor alpha (TNFalpha) through a mechanism dependent on the production of O(2) and completely independent of NO. Expression of eNOS in transfected U937 cells increased phorbol 12-myristate 13-acetate-induced TNFalpha promoter activity and TNFalpha production. N(omega)-Methyl-l-arginine, an inhibitor of eNOS that blocks NO production but not its NADPH oxidase activity, did not prevent TNFalpha up-regulation. Likewise, Gln(361)eNOS, a competent NADPH oxidase that lacks NOS activity, retained the ability to increase TNFalpha. Similar to the effect of eNOS, a O(2) donor dose-dependently increased TNFalpha production in differentiated U937 cells. In contrast, cotransfection of superoxide dismutase with eNOS prevented TNFalpha up-regulation, as did partial deletion of the eNOS NADPH binding site, a mutation associated with loss of O(2) production. Thus, eNOS may straddle a bifurcating pathway that can lead to the formation of either NO or O(2), interrelated but often opposing free radical messengers. This arrangement has possible implications for atherosclerosis and septic shock where endothelial dysfunction results from imbalances in NO and O(2) production. PMID:10747895

Wang, W; Wang, S; Yan, L; Madara, P; Del Pilar Cintron, A; Wesley, R A; Danner, R L

2000-06-01

89

Enhanced phagocytosis, chemotaxis, and production of reactive oxygen intermediates by interstitial lung macrophages following acute endotoxemia.  

PubMed

Endotoxemia is associated with enhanced release of a variety of cytotoxic and/or proinflammatory mediators from locally activated tissue macrophages. The lung is highly sensitive to damage induced by endotoxin, suggesting that pulmonary macrophages are activated by this bacterially derived product to release mediators that contribute to the pathogenesis of tissue injury. In the present studies, we used a rat model of acute endotoxemia induced by a single intravenous injection of animals with lipopolysaccharide (LPS) to determine the extent to which different lung macrophage subpopulations are activated. Alveolar macrophages (AM) and interstitial macrophages (IM) were isolated sequentially from the lung by lavage, followed by digestion with collagenase and selective adherence to tissue culture dishes. Both AM and IM were found to produce superoxide anion, as well as hydrogen peroxide in response to inflammatory stimuli. AM produced greater quantities of these reactive oxygen intermediates than did IM. Treatment of rats with LPS resulted in a significant increase in production of reactive oxygen intermediates by IM, but not by AM. Similarly, while AM from untreated rats phagocytized more opsonized sheep red blood cells than did IM, LPS treatment of rats significantly enhanced phagocytosis only in IM. In addition, this treatment caused a significant increase in chemotaxis of IM towards C5a. In contrast, although LPS treatment of rats had no effect on tumor necrosis factor-alpha release by AM, a significant reduction was observed in IM. Taken together, these data demonstrate that IM play a role in the inflammatory response of the lung to acute endotoxemia. PMID:8086172

Wizemann, T M; Laskin, D L

1994-09-01

90

Multiple scattering effects on heavy meson production in p+A collisions at backward rapidity  

E-print Network

We study the incoherent multiple scattering effects on heavy meson production in the backward rapidity region of p+A collisions within the generalized high-twist factorization formalism. We calculate explicitly the double scattering contributions to the heavy meson differential cross sections by taking into account both initial-state and final-state interactions, and find that these corrections are positive. We further evaluate the nuclear modification factor for muons that come form the semi-leptonic decays of heavy flavor mesons. Phenomenological applications in d+Au collisions at a center-of-mass energy $\\sqrt{s}=200$ GeV at RHIC and in p+Pb collisions at $\\sqrt{s}=5.02$ TeV at the LHC are presented. We find that incoherent multiple scattering can describe rather well the observed nuclear enhancement in the intermediate $p_T$ region for such reactions.

Kang, Zhong-Bo; Wang, Enke; Xing, Hongxi; Zhang, Cheng

2014-01-01

91

Aryl hydrocarbon receptor protects against bacterial infection by promoting macrophage survival and reactive oxygen species production.  

PubMed

Aryl hydrocarbon receptor (AhR) is crucial for various immune responses. The relationship between AhR and infection with the intracellular bacteria Listeria monocytogenes (LM) is poorly understood. Here, we show that in response to LM infection, AhR is required for bacterial clearance by promoting macrophage survival and reactive oxygen species (ROS) production. AhR-deficient mice were more susceptible to listeriosis, and AhR deficiency enhances bacterial growth in vivo and in vitro. On the other hand, pro-inflammatory cytokines were increased in AhR-deficient macrophages infected with LM despite enhanced susceptibility to LM infection in AhR-deficient mice. Subsequent studies demonstrate that AhR protects against macrophage cell death induced by LM infection through the induction of the antiapoptotic factor, the apoptosis inhibitor of macrophages, which promotes macrophage survival in the setting of LM infection. Furthermore, AhR promotes ROS production for bacterial clearance. Our results demonstrate that AhR is essential to the resistance against LM infection as it promotes macrophage survival and ROS production. This suggests that the activation of AhR by its ligands may be an effective strategy against listeriosis. PMID:24343818

Kimura, Akihiro; Abe, Hiromi; Tsuruta, Sanae; Chiba, Sayuri; Fujii-Kuriyama, Yoshiaki; Sekiya, Takashi; Morita, Rimpei; Yoshimura, Akihiko

2014-04-01

92

Licochalcone A inhibiting proliferation of bladder cancer T24 cells by inducing reactive oxygen species production.  

PubMed

The aim of this study was to determine the relationship between proliferation inhibition and the production of reactive oxygen species (ROS) induced by Licochalcone A (LCA). Cell viability was evaluated using sulforhodamine B (SRB) assay. Intracellular ROS level was assessed using the 2, 7-dichlorofluorescein diacetate (H2DCFDA) probe and dihydroethidium (DHE) probe assay. The results indicate that LCA inhibits human bladder cancer T24 proliferation in a concentration-dependent manner, with an IC50 value of approximately 55 ?M. The LCA-induced ROS production is inhibited by the co-treatment of LCA and free radical scavenger N-acetyl-cysteine (NAC), on the contrary, the proliferation rate and ROS production increase when treated by the combination of LCA and L-buthionine-(S,R)-sulfoximine (BSO). The ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG) decreases in a concentration-dependent manner. The results suggest that LCA inhibits proliferation by increasing intracellular ROS levels resulted in an oxidative stress status in T24 cells. PMID:24211992

Jiang, Jiangtao; Yuan, Xuan; Zhao, Hong; Yan, Xinyan; Sun, Xiling; Zheng, Qiusheng

2014-01-01

93

Coherent Neutron Scattering in Polycrystalline Deuterium and its Implications for Ultracold Neutron Production  

E-print Network

This paper presents a calculation of the neutron cross-sections in solid materials (used in practical neutron sources) with a large coherent scattering contribution. In particular, the dynamic structure function S(Q, $\\omega$) of polycrystalline ortho-D$_2$ is evaluated using a Monte-Carlo calculation that performs an average over scattering angles relative to crystal axes in random orientations. This method uses an analytical dispersion function with force constants derived from neutron scattering data of single crystal D$_2$ in the framework of an axially symmetric force tensor. The resulting two dimensional map of S(Q, $\\omega$) captures details of the phonon branches as well as the molecular rotations, that can be compared directly to data from inelastic neutron scattering on polycrystalline D$_2$. This high resolution information is used to calculate the absolute cross-sections of production and upscattering loss of ultracold neutron (UCN). The resulting scattering cross-sections are significantly different, especially for UCN upscattering, from the previous predictions using the approach centered on the incoherent approximation.

C. -Y. Liu; A. R. Young; C. M. Lavelle; D. Salvat

2010-05-06

94

Quantum reactive scattering of O((3)P)+H2 at collision energies up to 4.4 eV.  

PubMed

We report the results of quantum scattering calculations for the O((3)P)+H2 reaction for a range of collision energies from 0.4 to 4.4 eV, important for astrophysical and atmospheric processes. The total and state-to-state reactive cross sections are calculated using a fully quantum time-independent coupled-channel approach on recent potential energy surfaces of (3)A(') and (3)A(?) symmetry. A larger basis set than in the previous studies was used to ensure single-surface convergence at higher energies. Our results agree well with the published data at lower energies and indicate the breakdown of reduced dimensionality approach at collision energies higher than 1.5 eV. Differential cross sections and momentum transfer cross sections are also reported. PMID:25362316

Gacesa, Marko; Kharchenko, Vasili

2014-10-28

95

Butein suppresses breast cancer growth by reducing a production of intracellular reactive oxygen species  

PubMed Central

Background Butein has various functions in human diseases including cancer. While anti-cancer effects of butein have been revealed, it is urgent to understand a unique role of butein against cancer. In this study, we demonstrate that butein inhibition of reactive oxygen species (ROS) production results in suppression of breast cancer growth. Methods Different breast cancer cell lines were treated with butein and then subjected to cell viability and apoptosis assays. Butein-sensitive or -resistant breast cancer cells were injected into mammary fat pads of immunocompromised mice and then butein was injected. Breast cancer cells were categorized on the basis of butein sensitivity. Results Butein reduced viabilities of different breast cancer cells, while not affecting those of HER2-positive (HER2+) HCC-1419, SKBR-3 and HCC-2218 breast cancer cells. Butein reduction of ROS levels was correlated with apoptotic cell death. Furthermore, butein reduction of ROS level led to inhibitions of AKT phosphorylation. N-acetyl-L-cysteine (NAC), a free radical scavenger, also reduced ROS production and AKT phosphorylation, resulting in apoptotic cell death. In contrast, inhibitory effects of both butein and NAC on ROS production and AKT phosphorylation were not detected in butein-resistant HER2+ HCC-1419, SKBR-3 and HCC-2218 cells. In the in vivo tumor growth assays, butein inhibited tumor growth of butein-sensitive HER2+ BT-474 cells, while not affecting that of butein-resistant HER2+ HCC-1419 cells. Moreover, butein inhibition of ROS production and AKT phosphorylation was confirmed by in vivo tumor growth assays. Conclusions Our study first reveals that butein causes breast cancer cell death by the reduction of ROS production. Therefore, our finding provides better knowledge for butein effect on breast cancer and also suggests its treatment option. PMID:24919544

2014-01-01

96

Differential effects of mitochondrial Complex I inhibitors on production of reactive oxygen species.  

PubMed

We have investigated the production of reactive oxygen species (ROS) by Complex I in isolated open bovine heart submitochondrial membrane fragments during forward electron transfer in presence of NADH, by means of the probe 2',7'-Dichlorodihydrofluorescein diacetate. ROS production by Complex I is strictly related to its inhibited state. Our results indicate that different Complex I inhibitors can be grouped into two classes: Class A inhibitors (Rotenone, Piericidin A and Rolliniastatin 1 and 2) increase ROS production; Class B inhibitors (Stigmatellin, Mucidin, Capsaicin and Coenzyme Q(2)) prevent ROS production also in the presence of Class A inhibitors. Addition of the hydrophilic Coenzyme Q(1) as an electron acceptor potentiates the effect of Rotenone-like inhibitors in increasing ROS production, but has no effect in the presence of Stigmatellin-like inhibitors; the effect is not shared by more hydrophobic quinones such as decyl-ubiquinone. This behaviour relates the prooxidant CoQ(1) activity to a hydrophilic electron escape site. Moreover the two classes of Complex I inhibitors have an opposite effect on the increase of NADH-DCIP reduction induced by short chain quinones: only Class B inhibitors allow this increase, indicating the presence of a Rotenone-sensitive but Stigmatellin-insensitive semiquinone species in the active site of the enzyme. The presence of this semiquinone was also suggested by preliminary EPR data. The results suggest that electron transfer from the iron-sulphur clusters (N2) to Coenzyme Q occurs in two steps gated by two different conformations, the former being sensitive to Rotenone and the latter to Stigmatellin. PMID:19059197

Fato, Romana; Bergamini, Christian; Bortolus, Marco; Maniero, Anna Lisa; Leoni, Serena; Ohnishi, Tomoko; Lenaz, Giorgio

2009-05-01

97

Differential effects of mitochondrial Complex I inhibitors on production of reactive oxygen species  

PubMed Central

We have investigated the production of reactive oxygen species (ROS) by Complex I in isolated open bovine heart submitochondrial membrane fragments during forward electron transfer in presence of NADH, by means of the probe 2?,7?-Dichlorodihydrofluorescein diacetate. ROS production by Complex I is strictly related to its inhibited state. Our results indicate that different Complex I inhibitors can be grouped into two classes: Class A inhibitors (Rotenone, Piericidin A and Rolliniastatin 1 and 2) increase ROS production; Class B inhibitors (Stigmatellin, Mucidin, Capsaicin and Coenzyme Q2) prevent ROS production also in the presence of Class A inhibitors. Addition of the hydrophilic Coenzyme Q1 as an electron acceptor potentiates the effect of Rotenone-like inhibitors in increasing ROS production, but has no effect in the presence of Stigmatellin-like inhibitors; the effect is not shared by more hydrophobic quinones such as decylubiquinone. This behaviour relates the prooxidant CoQ1 activity to a hydrophilic electron escape site. Moreover the two classes of Complex I inhibitors have an opposite effect on the increase of NADH–DCIP reduction induced by short chain quinones: only Class B inhibitors allow this increase, indicating the presence of a Rotenone-sensitive but Stigmatellin-insensitive semiquinone species in the active site of the enzyme. The presence of this semiquinone was also suggested by preliminary EPR data. The results suggest that electron transfer from the iron–sulphur clusters (N2) to Coenzyme Q occurs in two steps gated by two different conformations, the former being sensitive to Rotenone and the latter to Stigmatellin. PMID:19059197

Fato, Romana; Bergamini, Christian; Bortolus, Marco; Maniero, Anna Lisa; Leoni, Serena; Ohnishi, Tomoko; Lenaz, Giorgio

2009-01-01

98

Urea degradation by electrochemically generated reactive chlorine species: products and reaction pathways.  

PubMed

This study investigated the transformation of urea by electrochemically generated reactive chlorine species (RCS). Solutions of urea with chloride ions were electrolyzed using a bismuth doped TiO2 (BiOx/TiO2) anode coupled with a stainless steel cathode at applied anodic potentials (Ea) of either +2.2 V or +3.0 V versus the normal hydrogen electrode. In NaCl solution, the current efficiency of RCS generation was near 30% at both potentials. In divided cell experiments, the pseudo-first-order rate of total nitrogen decay was an order of magnitude higher at Ea of +3.0 V than at +2.2 V, presumably because dichlorine radical (Cl2(-)·) ions facilitate the urea transformation primary driven by free chlorine. Quadrupole mass spectrometer analysis of the reactor headspace revealed that N2 and CO2 are the primary gaseous products of the oxidation of urea, whose urea-N was completely transformed into N2 (91%) and NO3(-) (9%). The higher reaction selectivity with respect to N2 production can be ascribed to a low operational ratio of free available chlorine to N. The mass-balance analysis recovered urea-C as CO2 at 77%, while CO generation most likely accounts for the residual carbon. In light of these results, we propose a reaction mechanism involving chloramines and chloramides as reaction intermediates, where the initial chlorination is the rate-determining step in the overall sequence of reactions. PMID:25219459

Cho, Kangwoo; Hoffmann, Michael R

2014-10-01

99

J/psi Inclusive Production in ep Deep-Inelastic Scattering at DESY HERA  

E-print Network

We calculate the cross section of J/psi plus jet associated production in ep deep-inelastic scattering within the factorization formalism of nonrelativistic quantum chromodynamics. Our analytic results disagree with previous analyses, both for the colour-singlet and colour-octet channels. Our theoretical predictions agree reasonably well with recent data taken by the H1 Collaboration at DESY HERA, significantly better than those obtained within the colour-singlet model.

Kniehl, Bernd A; Kniehl, Bernd A.; Zwirner, Lennart

2002-01-01

100

Study of hard scattering processes in multihadron production from ?? collisions at LEP  

Microsoft Academic Search

The production of multihadronic states in ?? collisions at LEP has been studied with the DELPHI detector. The analyzed data correspond to an integrated luminosity of about 32pb-1, collected in the LEP runs of 1990–1992. Minimum bias data and a sample of events with jets at highpT have been selected under the requirement that no scattered electron or positron is

P. Abreu; W. Adam; T. Adye; E. Agasi; R. Aleksan; G. D. Alekseev; P. Allport; S. Almehed; F. M. L. Almeida Junior; S. J. Alvsvaag; U. Amaldi; A. Andreazza; P. Antilogus; W.-D. Apel; R. J. Apsimon; Y. Arnoud; B. Åsman; J.-E. Augustin; A. Augustinus; P. Baillon; P. Bambade; F. Barao; R. Barate; G. Barbiellini; D. Y. Bardin; G. J. Barker; A. Baroncelli; O. Barring; J. A. Barrio; W. Bartl; M. J. Bates; M. Battaglia; M. Baubillier; K.-H. Becks; M. Begalli; P. Beilliere; Yu. Belokopytov; P. Beltran; A. C. Benvenuti; M. Berggren; D. Bertrand; F. Bianchi; M. Bigi; M. S. Bilenky; P. Billoir; J. Bjarne; D. Bloch; J. Blocki; S. Blyth; V. Bocci; P. N. Bogolubov; T. Bolognese; M. Bonesini; W. Bonivento; P. S. L. Booth; G. Borisov; C. Bosio; B. Bostjancic; S. Bosworth; O. Botner; B. Bouquet; C. Bourdarios; T. J. V. Bowcock; M. Bozzo; S. Braibant; P. Branchini; K. D. Brand; R. A. Brenner; H. Briand; C. Bricman; L. Brillault; R. C. A. Brown; P. Bruckman; J.-M. Brunet; A. Budziak; L. Bugge; T. Buran; A. Buys; J. A. M. A. Buytaert; M. Caccia; M. Calvi; A. J. Camacho Rozas; R. Campion; T. Bamporesi; V. Canale; K. Cankocak; F. Cao; F. Carena; P. Carrilho; L. Carroll; R. Cases; M. V. Castillo Gimenez; A. Cattai; F. R. Cavallo; L. Cerrito; V. Chabaud; A. Chan; M. Chapkin; Ph. Charpentier; J. Chauveau; P. Checchia; G. A. Chelkov; L. Chevalier; P. Chliapnikov; V. Chorowicz; J. T. M. Chrin; V. Cindro; P. Collins; J. L. Contreras; R. Contri; E. Cortina; G. Cosme; F. Couchot; H. B. Crawley; D. Crennell; G. Crosetti; J. Cuevas Maestro; S. Czellar; E. Dahl-Jensen; J. Dahm; B. Dalmagne; M. Dam; G. Damgaard; G. Darbo; E. Daubie; A. Daum; P. D. Dauncey; M. Davenport; J. Davies; J. Da Silva; C. Defoix; P. Delpierre; N. Demaria; A. De Angelis; H. De Boeck; W. De Boer; S. De Brabandere; C. De Clerq; M. D. M. De Fez Laso; C. De La Vaissiere; B. De Lotto; A. De Min; L. De Paula; H. Dijkstra; L. Di Ciaccio; F. Djama; J. Dolbeau; M. Donszelmann; K. Doroba; M. Dracos; J. Drees; M. Dris; Y. Dufour; F. Dupont; D. Edsall; L.-O. Eek; R. Ehret; T. Ekelof; G. Ekspong; A. Elliot Peisert; M. Elsing; J.-P. Engel; N. Ershaidat; M. Espirito Santo; D. Fassouliotis; M. Feindt; A. Fenyuk; A. Ferrer; T. A. Filippas; A. Firestone; H. Foeth; E. Fokitis; F. Fontanelli; K. A. J. Forbes; F. Formenti; J.-L. Fousset; S. Francon; B. Franek; P. Frenkiel; D. C. Fries; A. G. Frodesen; R. Fruhwirth; F. Fulda-Quenzer; H. Furstenau; J. Fuster; D. Gamba; M. Gandelman; C. Garcia; J. Garcia; C. Gaspar; U. Gasparini; Ph. Gavillet; E. N. Gazis; J.-P. Gerber; P. Giacomelli; D. Gillespie; R. Gokieli; B. Golob; V. M. Golovatyuk; J. J. Gomez Y Cadenas; G. Gopal; L. Gorn; M. Gorski; V. Gracco; F. Grard; E. Graziani; G. Grosdidier; B. Grossetete; P. Gunnarsson; J. Guy; U. Haedinger; F. Hahn; M. Hahn; S. Hahn; S. Haider; Z. Hajduk; A. Hakansson; A. Hallgren; U. Hamacher; G. Hamel De Monchenault; W. Hao; F. J. Harris; V. Hedberg; R. Henriques; J. J. Hernandez; J. A. Hernando; P. Herquet; H. Herr; T. L. Hessing; C. O. Higgins; E. Higon; H. J. Hilke; T. S. Hill; S. D. Hodgson; T. Hofmokl; S.-O. Holmgren; P. J. Holt; D. Holthuizen; P. F. Honore; M. Houlden; K. Huet; K. Hultqvist; P. Ioannou; P.-S. Iversen; J. N. Jackson; R. Jacobsson; P. Jalocha; G. Jarlskog; P. Jarry; B. Jean-Marie; E. K. Johansson; M. Jonker; L. Jonsson; P. Juillot; M. Kaiser; G. Kalkanis; G. Kalmus; F. Kapusta; M. Karlsson; E. Karvelas; S. Katsanevas; E. C. Katsoufis; R. Keranen; B. A. Khomenko; N. N. Khovanski; B. King; N. J. Kjaer; H. Klein; A. Klovning; P. Kluit; A. Koch-Mehrin; J. H. Koehne; B. Koene; P. Kokkinias; M. Koratzinos; K. Korcyl; A. V. Korytov; V. Kostioukhine; C. Kourkoumelis; O. Kouznetsov; P. H. Kramer; M. Krammer; C. Kreuter; J. Krolikowski; I. Kronkvist; W. Krupinski; W. Kucewicz; K. Kulka; K. Kurvinen; C. Lacasta; C. Lambropoulos; J. W. Lamsa; L. Lanceri; P. Langefeld; V. Lapin; I. Last; J.-P. Laugier; R. Lauhakangas; G. Leder; F. Ledroit; R. Leitner; Y. Lemoigne; J. Lemonne; G. Lenzen; V. Lepeltier; J. M. Levy; E. Lieb; D. Liko; J. Lindgren; R. Lindner; A. Lipniacka; I. Lippi; B. Loerstad; M. Lokajicek; J. G. Loken; A. Lopez-Fernandez; M. A. Lopez Aguera; M. Los; D. Loukas; J. J. Lozano; P. Lutz; L. Lyons; G. Maehlum; J. Maillard; A. Maio; A. Maltezos; F. Mandl; J. Marco; B. Marechal; M. Margoni; J.-C. Marin; C. Mariotti; A. Markou; T. Maron; S. Marti; C. Martinez-Rivero; F. Martinez-Vidal; F. Matorras; C. Matteuzzi; G. Matthiae; M. Mazzucato; M. McCubbin; R. McKay; R. McNulty; J. Medbo; C. Meroni; W. T. Meyer; M. Michelotto; E. Migliore; I. Mikulec; L. Mirabito; W. A. Mitaroff; G. V. Mitselmakher; U. Mjoernmark; T. Moa; R. Moeller; K. Moenig; M. R. Monge; P. Morettini; H. Mueller; W. J. Murray; B. Muryn; G. Myatt; F. Naraghi; F. L. Navarria; P. Negri; S. Nemecek; W. Neumann; N. Neumeister; R. Nicolaidou; B. S. Nielsen; V. Nikolaenko

1994-01-01

101

D* production in deep-inelastic Scattering at low Q2  

E-print Network

Inclusive production of D* mesons in deep-inelastic scattering at HERA is studied in the range 5 D* meson is p_T (D*) > 1.25 GeV and |\\eta(D*)| < 1.8. The data were taken with the H1 detector in the years 2004 to 2007 and correspond to an integrated luminosity of 347 pb^{-1}. Single and double differential cross sections are measured. The results are compared to QCD predictions.

Andreas W. Jung

2011-10-10

102

Characterisation and O 2 titration of CO islands on Pt 100: helium atom scattering and reactive sticking probability measurements  

NASA Astrophysics Data System (ADS)

Thermal energy atom scattering (TEAS) has been used simultaneously with molecular beam adsorption and thermal desorption to probe the lateral distribution of CO on a Pt 100 single-crystal surface. On the initial hex-R phase at 350 K, (1 × 1) island growth occurs at a constant local coverage ( ?(1 × 1)CO) of 0.4 ML. However, during desorption the surface remains wholly in the (1 × 1) state until ( ?(1 × 1)CO) ? 0.25 ML. Subsequent reconstruction to hex occurs at a constant local coverage of 0.19 ML in the remaining (1 × 1) domains. Hysteresis is not observed for the pre-prepared (1 × 1) surface, on which a random CO distribution is observed during adsorption. The scattering cross-section ? for a single CO molecule on the hex-R and (1 × 1) surfaces at 350 K has been determined as 71 ± 10 and 130 ± 18Å 2 respectively. The behaviour during oxidation of (1 × 1)-CO islands on the initial hex-R surface prepared by either adsorption or desorption is found to be consistent with the TEAS data. The first sticking probabilities for O 2 and CO on the CO ad-freed and O ad-freed (1 × 1) phase of Pt 100 are also reported.

Pasteur, A. T.; Guo, X.-C.; Ali, T.; Gruyters, M.; King, D. A.

1996-11-01

103

Correlation between change in pulmonary function and suppression of reactive nitrogen species production following steroid treatment in COPD  

Microsoft Academic Search

Background: Reactive nitrogen species (RNS) have a number of inflammatory actions and the production of these molecules has been reported to be increased in the airways of patients with chronic obstructive pulmonary disease (COPD), which suggests that they may be involved in the inflammatory and obstructive process in COPD.Methods: The relationship between the reduction in RNS and the improvement in

H Sugiura; M Ichinose; S Yamagata; A Koarai; K Shirato; T Hattori

2003-01-01

104

Ozone production rate and hydrocarbon reactivity in 5 urban areas: A cause of high ozone concentration in Houston  

E-print Network

stringent emis- sion controls, approximately 1/3 of the population of the U.S. is exposed to ground level O3Ozone production rate and hydrocarbon reactivity in 5 urban areas: A cause of high ozone; revised 3 April 2002; accepted 5 April 2002; published 28 May 2002. [1] Observations of ozone (O3) and O3

105

From the Cover: Somatic mtDNA mutations cause aging phenotypes without affecting reactive oxygen species production  

Microsoft Academic Search

The mitochondrial theory of aging proposes that reactive oxygen species (ROS) generated inside the cell will lead, with time, to increasing amounts of oxidative damage to various cell components. The main site for ROS production is the respiratory chain inside the mitochondria and accumulation of mtDNA mutations, and impaired respiratory chain function have been associated with degenerative diseases and aging.

Aleksandra Trifunovic; Anna Hansson; Anna Wredenberg; Anja T. Rovio; Eric Dufour; Ivan Khvorostov; Johannes N. Spelbrink; Rolf Wibom; Howard T. Jacobs; Nils-Göran Larsson

2005-01-01

106

Extending cassava root shelf life via reduction of reactive oxygen species production.  

PubMed

One of the major constraints facing the large-scale production of cassava (Manihot esculenta) roots is the rapid postharvest physiological deterioration (PPD) that occurs within 72 h following harvest. One of the earliest recognized biochemical events during the initiation of PPD is a rapid burst of reactive oxygen species (ROS) accumulation. We have investigated the source of this oxidative burst to identify possible strategies to limit its extent and to extend cassava root shelf life. We provide evidence for a causal link between cyanogenesis and the onset of the oxidative burst that triggers PPD. By measuring ROS accumulation in transgenic low-cyanogen plants with and without cyanide complementation, we show that PPD is cyanide dependent, presumably resulting from a cyanide-dependent inhibition of respiration. To reduce cyanide-dependent ROS production in cassava root mitochondria, we generated transgenic plants expressing a codon-optimized Arabidopsis (Arabidopsis thaliana) mitochondrial alternative oxidase gene (AOX1A). Unlike cytochrome c oxidase, AOX is cyanide insensitive. Transgenic plants overexpressing AOX exhibited over a 10-fold reduction in ROS accumulation compared with wild-type plants. The reduction in ROS accumulation was associated with a delayed onset of PPD by 14 to 21 d after harvest of greenhouse-grown plants. The delay in PPD in transgenic plants was also observed under field conditions, but with a root biomass yield loss in the highest AOX-expressing lines. These data reveal a mechanism for PPD in cassava based on cyanide-induced oxidative stress as well as PPD control strategies involving inhibition of ROS production or its sequestration. PMID:22711743

Zidenga, Tawanda; Leyva-Guerrero, Elisa; Moon, Hangsik; Siritunga, Dimuth; Sayre, Richard

2012-08-01

107

Mitochondrial Reactive Oxygen Species Production in Excitable Cells: Modulators of Mitochondrial and Cell Function  

PubMed Central

Abstract The mitochondrion is a major source of reactive oxygen species (ROS). Superoxide (O2•?) is generated under specific bioenergetic conditions at several sites within the electron-transport system; most is converted to H2O2 inside and outside the mitochondrial matrix by superoxide dismutases. H2O2 is a major chemical messenger that, in low amounts and with its products, physiologically modulates cell function. The redox state and ROS scavengers largely control the emission (generation scavenging) of O2•?. Cell ischemia, hypoxia, or toxins can result in excess O2•? production when the redox state is altered and the ROS scavenger systems are overwhelmed. Too much H2O2 can combine with Fe2+ complexes to form reactive ferryl species (e.g., Fe(IV)?=?O•). In the presence of nitric oxide (NO•), O2•? forms the reactant peroxynitrite (ONOO?), and ONOOH-induced nitrosylation of proteins, DNA, and lipids can modify their structure and function. An initial increase in ROS can cause an even greater increase in ROS and allow excess mitochondrial Ca2+ entry, both of which are factors that induce cell apoptosis and necrosis. Approaches to reduce excess O2•? emission include selectively boosting the antioxidant capacity, uncoupling of oxidative phosphorylation to reduce generation of O2•? by inducing proton leak, and reversibly inhibiting electron transport. Mitochondrial cation channels and exchangers function to maintain matrix homeostasis and likely play a role in modulating mitochondrial function, in part by regulating O2•? generation. Cell-signaling pathways induced physiologically by ROS include effects on thiol groups and disulfide linkages to modify posttranslationally protein structure to activate/inactivate specific kinase/phosphatase pathways. Hypoxia-inducible factors that stimulate a cascade of gene transcription may be mediated physiologically by ROS. Our knowledge of the role played by ROS and their scavenging systems in modulation of cell function and cell death has grown exponentially over the past few years, but we are still limited in how to apply this knowledge to develop its full therapeutic potential. Antioxid. Redox Signal. 11, 1373–1414. PMID:19187004

Camara, Amadou K. S.

2009-01-01

108

Cobalt Protoporphyrin Induces HO-1 Expression Mediated Partially by FOXO1 and Reduces Mitochondria-Derived Reactive Oxygen Species Production  

PubMed Central

Background Reactive oxygen species arise in the mitochondria as byproducts of respiration and oxidase activity and have important roles in many physiological and pathophysiological conditions. The level of reactive oxygen species is regulated by a number of enzymes and physiological antioxidants, including HO-1, Sod2, catalase and COX-2, etc. And HO-1 against oxidative stress requires an increase in stress-responsive genes, such as Sod2 and catalase. Especially for the activity of HO-1, cobalt protoporphyrin is known to be a potent and effective inducer in many tissues. The transcription factor, FOXO1 is resistant to oxidative stress through downregulating reactive oxygen species production. Previous study showed that FOXO1 induces HO-1 expression by binding to HO-1 promoter. The question whether cobalt protoporphyrin induces HO-1 expression mediated by FOXO1 and subsequently lessens reactive oxygen species production remains to be elucidated. Results Cobalt protoporphyrin enhances the expression of FOXO1 and facilitates FOXO1 binding to HO-1 promoter and increasing its transcriptional activity without influencing the FOXO1 protein stability. CoPP induces HO-1 and other oxidative stress-responsive genes expression, such as catalase, cytochrome c, Sod2, and COX-2, and decreases mitochondria-derived reactive oxygen species production, which are mediated partially by FOXO1. Conclusions Cobalt protoporphyrin induces HO-1 and other oxidative stress-responsive genes expression mediated partially by FOXO1, and has an important role in reducing cellular reactive oxygen species level. Cobalt protoporphyrin may be a more promising therapeutic agent to upregulate some antioxidantive genes. PMID:24255720

Li, Meixia; Xu, Haifeng; Zuo, Jin; Fang, Fude; Chang, Yongsheng

2013-01-01

109

Pion-nucleon scattering and pion production in nucleon-nucleon and nucleus-nucleus collisions  

SciTech Connect

Lecture notes are presented on the following: (1) basic aspects of ..pi..N interactions (properties of pions and nucleons, SU(3) and SU(6) classification phenomenology of ..pi..N scattering ((3.3) resonance; phase shift analysis, and bag model approach to ..pi..N); (2) pion production and absorption in the two nucleon system (NN ..-->.. NN..pi.. (isobar model) and ..pi..d reversible NN (existence of dibaryon resonances)); (3) pion absorption in complex nuclei (multiparticle aspects and cascade calculations); and (4) pion production with nuclear targets including (a) nucleon-nucleus, (b) nucleus-nucleus (Fermi-averaged 2-body vs thermodynamic models), and (c) ..pi pi.. interoferometry.

Dover, C.B.

1982-01-01

110

Mitochondrial Respiratory Supercomplex Association Limits Production of Reactive Oxygen Species from Complex I  

PubMed Central

Abstract Aims: The mitochondrial respiratory chain is recognized today to be arranged in supramolecular assemblies (supercomplexes). Besides conferring a kinetic advantage (substrate channeling) and being required for the assembly and stability of Complex I, indirect considerations support the view that supercomplexes may also prevent excessive formation of reactive oxygen species (ROS) from the respiratory chain. In the present study, we have directly addressed this issue by testing the ROS generation by Complex I in two experimental systems in which the supramolecular organization of the respiratory assemblies is impaired by: (i) treatment either of bovine heart mitochondria or liposome-reconstituted supercomplex I-III with dodecyl maltoside; (ii) reconstitution of Complexes I and III at high phospholipids to protein ratio. Results: The results of our investigation provide experimental evidence that the production of ROS is strongly increased in either model, supporting the view that disruption or prevention of the association between Complex I and Complex III by different means enhances the generation of superoxide from Complex I. Innovation: Dissociation of supercomplexes may link oxidative stress and energy failure in a vicious circle. Conclusion: Our findings support a central role of mitochondrial supramolecular structure in the development of the aging process and in the etiology and pathogenesis of most major chronic diseases. Antioxid. Redox Signal. 19, 1469–1480. PMID:23581604

Maranzana, Evelina; Barbero, Giovanna; Falasca, Anna Ida; Lenaz, Giorgio

2013-01-01

111

Reactive oxygen species production in mitochondria of human gingival fibroblast induced by blue light irradiation.  

PubMed

In recent years, it has become well known that the production of reactive oxygen species (ROS) induced by blue-light irradiation causes adverse effects of photo-aging, such as age-related macular degeneration of the retina. Thus, orange-tinted glasses are used to protect the retina during dental treatment involving blue-light irradiation (e.g., dental resin restorations or tooth bleaching treatments). However, there are few studies examining the effects of blue-light irradiation on oral tissue. For the first time, we report that blue-light irradiation by quartz tungsten halogen lamp (QTH) or light-emitting diode (LED) decreased cell proliferation activity of human gingival fibroblasts (HGFs) in a time-dependent manner (<5 min). Additionally, in a morphological study, the cytotoxic effect was observed in the cell organelles, especially the mitochondria. Furthermore, ROS generation induced by the blue-light irradiation was detected in mitochondria of HGFs using fluorimetry. In all analyses, the cytotoxicity was significantly higher after LED irradiation compared with cytotoxicity after QTH irradiation. These results suggest that blue light irradiation, especially by LED light sources used in dental aesthetic treatment, might have adverse effects on human gingival tissue. Hence, this necessitates the development of new dental aesthetic treatment methods and/or techniques to protect HGFs from blue light irradiation during dental therapy. PMID:24141287

Yoshida, Ayaka; Yoshino, Fumihiko; Makita, Tetsuya; Maehata, Yojiro; Higashi, Kazuyoshi; Miyamoto, Chihiro; Wada-Takahashi, Satoko; Takahashi, Shun-suke; Takahashi, Osamu; Lee, Masaichi Chang-il

2013-12-01

112

Reactivity of chlorine radical with submicron palmitic acid particles: kinetic measurements and products identification  

NASA Astrophysics Data System (ADS)

The heterogeneous reaction of Cl. radicals with sub-micron palmitic acid (PA) particles was studied in an aerosol flow tube in the presence or in the absence of O2. Fine particles were generated by homogeneous condensation of PA vapors and introduced in the reactor where chlorine atoms are produced by photolysis of Cl2 using UV lamps surrounding the reactor. The effective reactive uptake coefficient (?) has been determined from the rate loss of PA measured by GC/MS analysis of reacted particles as a function of the chlorine exposure. In the absence of O2, ? = 14 ± 5 indicates efficient secondary chemistry involving Cl2. GC/MS analyses have shown the formation of monochlorinated and polychlorinated compounds in the oxidized particles. Although, the PA particles are solid, the complete mass can be consumed. In the presence of oxygen, the reaction is still dominated by secondary chemistry but the propagation chain length is smaller than in the absence of O2 which leads to an uptake coefficient ? = 3 ± 1. In the particulate phase, oxocarboxylic acids and dicarboxylic acids are identified by GC/MS. Formation of alcohols and monocarboxylic acids are also suspected. All these results show that solid organic particles could be efficiently oxidized by gas-phase radicals not only on their surface, but also in bulk by mechanisms which are still unclear. Furthermore the identified reaction products are explained by a chemical mechanism showing the pathway of the formation of more functionalized products. They help to understand the aging of primary tropospheric aerosol containing fatty acids.

Mendez, M.; Ciuraru, R.; Gosselin, S.; Batut, S.; Visez, N.; Petitprez, D.

2013-06-01

113

A study of scattering, production, and stimulated emission of sound by vortex flows. [Bernouli enthalpy  

NASA Technical Reports Server (NTRS)

The basic theory of aeroacoustics of homentropic fluid media is applied to the problems of sound scattering, production, and stimulated emission. A general theory of scattering from low speed three-dimensional vortex flows is presented. Specific results are given for the horseshoe vortex and vortex ring. The noise of an elementary corotating vortex pair in various flows is calculated. It is shown that a potential flow and shear flow can substantially increase the basic pair noise. Small reverse shears can annihilate vortex pairs and eliminate the pair noise mechanism. The pair results are used to explain qualitatively the operation of noise suppression devices. The stimulated emission of a single vortex pair and four and six vortex arrays is demonstrated. The results for six vortices illustrate how external pure tones can amplify the broadband noise of a jet in agreement with recent experimental evidence.

Yates, J. E.

1979-01-01

114

Production of nitric oxide-derived reactive nitrogen species in human oral cavity and their scavenging by salivary redox components.  

PubMed

Nitrite is reduced to nitric oxide (NO) in the oral cavity. The NO generated can react with molecular oxygen producing reactive nitrogen species. In this study, reduction of nitrite to NO was observed in bacterial fractions of saliva and whole saliva. Formation of reactive nitrogen species from NO was detected by measuring the transformation of 4,5-diaminofluorescein (DAF-2) to triazolfluorescein (DAF-2T). The transformation was fast in bacterial fractions but slow in whole saliva. Salivary components such as ascorbate, glutathione, uric acid and thiocyanate inhibited the transformation of DAF-2 to DAF-2T in bacterial fractions without affecting nitrite-dependent NO production. The inhibition was deduced to be due to scavenging of reactive nitrogen species, which were formed from NO, by the above reagents. The transformation of DAF-2 to DAF-2T was faster in bacterial fractions and whole saliva which were prepared 1-4 h after tooth brushing than those prepared immediately after toothbrushing. Increase in the rate as a function of time after toothbrushing seemed to be due to the increase in population of bacteria which could reduce nitrite to NO. The results obtained in this study suggest that reactive nitrogen species derived from NO are continuously formed in the oral cavity and that the reactive nitrogen species are effectively scavenged by salivary redox components in saliva but the scavenging is not complete. PMID:16036353

Takahama, Umeo; Hirota, Sachiko; Oniki, Takayuki

2005-07-01

115

Rat colonic reactive oxygen species production and DNA damage are mediated by diet and age  

E-print Network

Colon cancer is the second leading cause of death from cancer in the United States. Studies suggest that oxidative damage to DNA caused by reactive oxygen species (ROS) is a critical initiating event in carcinogenesis. Rates of colon cancer...

Henderson, Cara Aletha Everett

2012-06-07

116

Deeply Virtual Compton Scattering and Meson Production at Jlab/CLAS  

SciTech Connect

This report reviews the recent experimental results from the CLAS collaboration (Hall B of Jefferson Lab, or JLab) on Deeply Virtual Compton Scattering (DVCS) and Deeply Virtual Meson Production (DVMP) and discusses their interpretation in the framework of Generalized Parton Distributions (GPDs). The impact of the experimental data on the applicability of the GPD mechanism to these exclusive reactions is discussed. Initial results obtained from JLab 6 GeV data indicate that DVCS might already be interpretable in this framework while GPD models fail to describe the exclusive meson production (DVMP) data with the GPD parameterizations presently used. An exception is the {phi} meson production for which the GPD mechanism appears to apply. The recent global analyses aiming to extract GPDs from fitting DVCS CLAS and world data are discussed. The GPD experimental program at CLAS12, planned with the upcoming 12 GeV upgrade of JLab, is briefly presented.

Hyon-Suk Jo

2012-04-01

117

Modulation of mitochondrial membrane potential and reactive oxygen species production by copper in astrocytes.  

PubMed

In monolayers of cultured rat astrocytes a number of agents that induce oxidative stress act synergistically with exposure to copper leading to rapid depolarization of the mitochondrial membrane potential (Psi m) and increased reactive oxygen species (ROS) production. Copper sensitized astrocytes to the action of menadione, an intracellular generator of superoxide anion radical, exogenous hydrogen peroxide (H2O2) and rotenone, an inhibitor of mitochondrial electron transport chain complex I. However, significant differences were observed in the ability to modulate the copper-enhanced oxidative stress depending on which stressor was used. The inhibitor of mitochondrial permeability transition cyclosporin A attenuated the effect of copper and rotenone, but had no protective action in the case of H2O2/copper and menadione/copper combinations. The H2O2 scavenger pyruvate was effective at protecting mitochondria against damage associated with the combined exposure to H2O2/copper and menadione/copper but not to the rotenone/copper combination. The antioxidant Trolox was ineffective at protecting against any of these actions and indeed had a damaging effect when combined with copper. The membrane-permeable copper chelator neocuproine combined with sensitizing concentrations of menadione caused a decrease in Psi m, mimicking the action of copper. Penicillamine, a membrane-impermeable copper chelator, was effective at reducing copper sensitization. Endogenous copper, mobilized during periods of oxidative stress, may play a role in the pathophysiology of brain injury. Our results suggest that this might be particularly dangerous in dysfunctional conditions in which the mitochondrial electron transport chain is compromised. PMID:14511122

Gyulkhandanyan, Armen V; Feeney, Chris J; Pennefather, Peter S

2003-10-01

118

Reactivity of chlorine radical with submicron palmitic acid particles: kinetic measurements and product identification  

NASA Astrophysics Data System (ADS)

The heterogeneous reaction of Cl• radicals with submicron palmitic acid (PA) particles was studied in an aerosol flow tube in the presence or in the absence of O2. Fine particles were generated by homogeneous condensation of PA vapours and introduced into the reactor, where chlorine atoms were produced by photolysis of Cl2 using UV lamps surrounding the reactor. The effective reactive uptake coefficient (?) has been determined from the rate loss of PA measured by gas chromatography-mass spectrometer (GC/MS) analysis of reacted particles as a function of the chlorine exposure. In the absence of O2, ? = 14 ± 5 indicates efficient secondary chemistry involving Cl2. GC/MS analysis has shown the formation of monochlorinated and polychlorinated compounds in the oxidized particles. Although the PA particles are solid, the complete mass can be consumed. In the presence of oxygen, the reaction is still dominated by secondary chemistry but the propagation chain length is smaller than in the absence of O2, which leads to an uptake coefficient ? = 3 ± 1. In the particulate phase, oxocarboxylic acids and dicarboxylic acids were identified by GC/MS. The formation of alcohols and monocarboxylic acids is also suspected. A reaction pathway for the main products and more functionalized species is proposed. All these results show that solid organic particles could be efficiently oxidized by gas-phase radicals not only on their surface but also in bulk by mechanisms which are still unclear. They help to understand the aging of primary tropospheric aerosol containing fatty acids.

Mendez, M.; Ciuraru, R.; Gosselin, S.; Batut, S.; Visez, N.; Petitprez, D.

2013-12-01

119

Photon production from the scattering of axions out of a solenoidal magnetic field  

SciTech Connect

We calculate the total cross section for the production of photons from the scattering of axions by a strong inhomogeneous magnetic field in the form of a 2D ?-function, a cylindrical step function and a 2D Gaussian distribution, which can be approximately produced by a solenoidal current. The theoretical result is used to estimate the axion-photon conversion probability which could be expected in a reasonable experimental situation. Comparison between the 2D conversion probabilities for QCD inspired axions and those derived by applying the celebrated 1D calculation of the (inverse) coherent Primakoff effect is made using an averaging prescription procedure of the 1D case. We also consider scattering at a resonance E{sub axion} ? m{sub axion}, which corresponds to the scattering from a ?-function and gives the most enhanced results. Finally, we analyze the results of this work in the astrophysical extension to suggest a way in which they may be directed to a solution to some basic solar physics problems and, in particular, the coronal heating problem.

Guendelman, Eduardo I.; Shilon, Idan [Physics Department, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel); Cantatore, Giovanni [Università and INFN Trieste, via Valerio 2, 34127 Trieste (Italy); Zioutas, Konstantin, E-mail: guendel@bgu.ac.il, E-mail: silon@bgu.ac.il, E-mail: cantatore@trieste.infn.it, E-mail: Konstantin.Zioutas@cern.ch [Physics Department, University of Patras, Rio, 26504 Patras (Greece)

2010-06-01

120

Double Parton Scattering in Associate Higgs Boson Production with Bottom Quarks at Hadron Colliders  

E-print Network

Higgs boson production in association with bottom quarks, is one of the most important discovery channels for Higgs particles in the Standard Model (SM) and its supersymmetric extension at the LHC pp collider . The theoretical prediction of the corresponding cross section has been improved by including the complete next-to-leading order QCD corrections. We review the status results for the leading order to the partonic process and present calculations for the integrated cross-section in both single and double parton scattering collisions.

M. Y. Hussein

2007-10-01

121

Single Spin Asymmetry in Inclusive Hadron Production in pp Scattering from Collins Mechanism  

SciTech Connect

We study the Collins mechanism contribution to the single transverse spin asymmetry in inclusive hadron production in pp scattering p{up_arrow}p {yields} {pi}X from the leading jet fragmentation. The azimuthal asymmetric distribution of hadron in the jet leads to a single spin asymmetry for the produced hadron in the Lab frame. The effect is evaluated in a transverse momentum dependent model that takes into account the transverse momentum dependence in the fragmentation process. We find the asymmetry is comparable in size to the experimental observation at RHIC at {radical}s = 200GeV.

Yuan, Feng; Yuan, Feng

2008-04-14

122

Adduct formation, mutagenesis and nucleotide excision repair of DNA damage produced by reactive oxygen species and lipid peroxidation product.  

PubMed

Reactive oxygen species are formed constantly in living organisms, as products of the normal metabolism, or as a result of many different environmental influences. Here we review the knowledge of formation of DNA damage, the mutations caused by reactive oxygen species and the role of the excision repair processes, that protect the organism from oxidative DNA damage. In particular, we have focused on recent studies that demonstrate the important role of nucleotide excision repair. We propose two major roles of nucleotide excision repair as 1) a backup when base excision repair of small oxidative lesions becomes saturated, and as 2) a primary repair pathway for DNA damage produced by lipid peroxidation products. PMID:9630671

Møller, P; Wallin, H

1998-06-01

123

In situ self-catalyzed reactive extraction of germinated oilseed with short-chained dialkyl carbonates for biodiesel production.  

PubMed

In order to eliminate the expense associated with solvent extraction and oil cleanup, and reduce the processing steps in biodiesel production, reactive extraction has become a focus of research in recent years. In this study, germinated castor seed was used as substrate and catalyst, dimethyl carbonate (DMC) was used as acyl acceptor and oil extractant to produce biodiesel. The optimum conditions were as follows: the germination time of castor seed was 72 h, DMC/germinated seed ratio was 12.5 ml/g, reaction temperature was 35°C, and water content was 2.11%. The biodiesel yield could reach as much as 87.41% under the optimized conditions. This germinated oilseed self-catalyzed reactive extraction can be a promising route for biodiesel production. PMID:24144599

Jiang, Yanjun; Li, Dan; Li, Yang; Gao, Jing; Zhou, Liya; He, Ying

2013-12-01

124

Mechanisms of uremic inhibition of phagocyte reactive species production: Characterization of the role of p-cresol  

Microsoft Academic Search

Mechanisms of uremic inhibition of phagocyte reactive species production: Characterization of the role of p-cresol. It is generally recognized that the uremic syndrome results in a depression of immune function, but the uremic solutes responsible remain largely unidentified. In this study, the effect of 18 known uremic retention solutes, including urea and creatinine, on hexose monophosphate shunt (HMS)-dependent glucose-1-C14 utilization

Raymond Vanholder; Rita De Smet; Marie-Anne Waterloos; Nadine Van Landschoot; Pascale Vogeleere; Eric Hoste; Severin Ringoir

1995-01-01

125

CARD9 facilitates microbe-elicited production of reactive oxygen species by regulating the LyGDI-Rac1 complex  

Microsoft Academic Search

In response to invading microorganisms, macrophages engage in phagocytosis and rapidly release reactive oxygen species (ROS), which serve an important microbicidal function. However, how phagocytosis induces ROS production remains largely unknown. CARD9, a caspase-recruitment domain (CARD)-containing protein, is important for resistance to fungal and bacterial infection. The mechanism of CARD9-mediated bacterial clearance is still mostly unknown. Here we show that

Weihui Wu; Yen-Michael S Hsu; Liangkuan Bi; Zhou Songyang; Xin Lin

2009-01-01

126

Reactive oxygen species production and antioxidative defense system in pea root tissues treated with lead ions: the whole roots level  

Microsoft Academic Search

The lead absorbed by the roots induce oxidative stress conditions through the Reactive oxygen species (ROS) production for\\u000a the pea plants cultivated hydroponically for 96 h on a Hoagland medium with the addition of 0.1 and 0.5 mM of Pb(NO3)2. The alterations in $$ {\\\\text{O}}_{2}^{ - \\\\cdot } $$ and H2O2 concentrations were monitored spectrophotometrically which show a rapid increase in $$

Arleta Malecka; Aneta Piechalak; Barbara Tomaszewska

2009-01-01

127

The production of reactive oxygen species by irradiated camphorquinone-related photosensitizers and their effect on cytotoxicity  

Microsoft Academic Search

Camphorquinone (CQ) is widely used as an initiator in modern light-cured resin systems but there are few reports about its effects on living cells. To clarify the mechanism of photosensitizer-induced cytotoxicity, the production of initiator radicals and subsequent reactive oxygen species (ROS) by CQ, benzil (BZ), benzophenone (BP), 9-fluorenone (9-F) in the presence of the reducing agent (2-dimethylaminoethyl methacrylate or

T Atsumi; I Iwakura; S Fujisawa; T Ueha

2001-01-01

128

On the Temperature Dependence of Organic Reactivity, Ozone Production, and the Impact of Emissions Controls in San Joaquin Valley California  

NASA Astrophysics Data System (ADS)

The San Joaquin Valley (SJV) experiences some of the worst ozone air quality in the U.S., frequently exceeding the California 8-h standard of 70.4 ppb. To improve our understanding of trends in the number of ozone violations in the SJV, we investigate observed relationships between organic reactivity, nitrogen oxides (NOx), and daily maximum temperature in the southern SJV using measurements made as part of California at the Nexus of Air Quality and Climate Change in 2010 (CalNex-SJV). We find the daytime speciated organic reactivity with respect OH during CalNex-SJV has a temperature-independent portion with molecules typically associated with motor vehicles being the major component. At high temperatures, characteristic of days with high ozone, the majority of the organic reactivity increases exponentially with temperature and is dominated by small oxygenated organics and molecules that are unidentified. We use this simple temperature classification to consider changes in organic emissions over the last and next decade. With the CalNex-SJV observations as constraints, we examine the sensitivity of ozone production (PO3) to future NOx and organic reactivity controls, finding that PO3 is NOx-limited at all temperatures on weekends and on weekdays when daily maximum temperatures are greater than 28oC. As a consequence, we show NOx reductions are the most effective control option for reducing the frequency of ozone violations in the southern SJV.

Pusede, S. E.; Gentner, D. R.; Wooldridge, P. J.; Browne, E. C.; Min, K.; Rollins, D. W.; Russell, A.; Thomas, J.; Zhang, L.; Brune, W. H.; Henry, S. B.; DiGangi, J. P.; Keutsch, F. N.; Harrold, S.; Thornton, J. A.; Beaver, M. R.; St Clair, J. M.; Wennberg, P. O.; Ren, X.; Sanders, J.; VandenBoer, T. C.; Markovic, M. Z.; Guha, A.; Weber, R.; Goldstein, A. H.; Cohen, R. C.

2013-12-01

129

Determination of the $?NN$ form factor from the threshold pion production of $pp$ scattering  

E-print Network

It is shown that the threshold productions of $\\pi^0 pp$, $\\pi^+ np$ and $\\pi^+ d$ from $pp$ collisions can be consistently described by a model consisting of a pion s-wave rescattering and $N\\bar N$ pair-terms of heavy-meson exchanges. The large difference between $\\sigma^{tot} (pp\\rightarrow\\pi ^+ d)$ and $\\sigma^{tot} (pp\\rightarrow\\pi ^+ np)$ is understood from the orthogonality of the deuteron and the $np$ scattering wave functions. In a calculation using the Paris potential to account for the initial and final $NN$ interactions, it is found that the data can be best reproduced by using a soft $\\pi NN$ form factor with $\\Lambda_{\\pi} =650 $ MeV for a monopole form. This is consistent with an earlier study of pion production in the $\\Delta$ excitation region.

T. -S. H. Lee

1995-02-02

130

Measurement of D + and ? c + production in deep inelastic scattering at HERA  

NASA Astrophysics Data System (ADS)

Charm production in deep inelastic scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 120 pb-1. The hadronic decay channels D + ? K S 0 ? +, ? c + ? pK S 0 and ? c + ? ? ? +, and their charge conjugates, were reconstructed. The presence of a neutral strange hadron in the final state reduces the combinatorial background and extends the measured sensitivity into the low transverse momentum region. The kinematic range is 0 < p T ( D +, ? c +) < 10 GeV, | ?( D +, ? c +)| < 1 .6, 1.5 < Q 2 < 1000 GeV2 and 0 .02 < y < 0.7. Inclusive and differential cross sections for the production of D + mesons are compared to next-to-leading-order QCD predictions. The fraction of c quarks hadronising into ? c + baryons is extracted.

Abramowicz, H.; Abt, I.; Adamczyk, L.; Adamus, M.; Aggarwal, R.; Antonelli, S.; Antonioli, P.; Antonov, A.; Arneodo, M.; Aushev, V.; Aushev, Y.; Bachynska, O.; Bamberger, A.; Barakbaev, A. N.; Barbagli, G.; Bari, G.; Barreiro, F.; Bartsch, D.; Basile, M.; Behnke, O.; Behr, J.; Behrens, U.; Bellagamba, L.; Bertolin, A.; Bhadra, S.; Bindi, M.; Blohm, C.; Bold, T.; Boos, E. G.; Borodin, M.; Borras, K.; Boscherini, D.; Bot, D.; Boutle, S. K.; Brock, I.; Brownson, E.; Brugnera, R.; Brümmer, N.; Bruni, A.; Bruni, G.; Brzozowska, B.; Bussey, P. J.; Butterworth, J. M.; Bylsma, B.; Caldwell, A.; Capua, M.; Carlin, R.; Catterall, C. D.; Chekanov, S.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cifarelli, L.; Cindolo, F.; Contin, A.; Cooper-Sarkar, A. M.; Coppola, N.; Corradi, M.; Corriveau, F.; Costa, M.; D'Agostini, G.; Dal Corso, F.; de Favereau, J.; Del Peso, J.; Dementiev, R. K.; de Pasquale, S.; Derrick, M.; Devenish, R. C. E.; Dobur, D.; Dolgoshein, B. A.; Doyle, A. T.; Drugakov, V.; Durkin, L. S.; Dusini, S.; Eisenberg, Y.; Ermolov, P. F.; Eskreys, A.; Fang, S.; Fazio, S.; Ferrando, J.; Ferrero, M. I.; Figiel, J.; Forrest, M.; Foster, B.; Fourletov, S.; Gach, G.; Galas, A.; Gallo, E.; Garfagnini, A.; Geiser, A.; Gialas, I.; Gladilin, L. K.; Gladkov, D.; Glasman, C.; Gogota, O.; Golubkov, Yu. A.; Göttlicher, P.; Grabowska-Bo?d, I.; Grebenyuk, J.; Gregor, I.; Grigorescu, G.; Grzelak, G.; Gwenlan, C.; Haas, T.; Hain, W.; Hamatsu, R.; Hart, J. C.; Hartmann, H.; Hartner, G.; Hilger, E.; Hochman, D.; Holm, U.; Hori, R.; Horton, K.; Hüttmann, A.; Iacobucci, G.; Ibrahim, Z. A.; Iga, Y.; Ingbir, R.; Ishitsuka, M.; Jakob, H.-P.; Januschek, F.; Jimenez, M.; Jones, T. W.; Jüngst, M.; Kadenko, I.; Kahle, B.; Kamaluddin, B.; Kananov, S.; Kanno, T.; Karshon, U.; Karstens, F.; Katkov, I. I.; Kaur, M.; Kaur, P.; Keramidas, A.; Khein, L. A.; Kim, J. Y.; Kisielewska, D.; Kitamura, S.; Klanner, R.; Klein, U.; Koffeman, E.; Kollar, D.; Kooijman, P.; Korol, Ie.; Korzhavina, I. A.; Kota?ski, A.; Kötz, U.; Kowalski, H.; Kulinski, P.; Kuprash, O.; Kuze, M.; Lee, A.; Levchenko, B. B.; Levy, A.; Libov, V.; Limentani, S.; Ling, T. Y.; Lisovyi, M.; Lobodzinska, E.; Lohmann, W.; Löhr, B.; Lohrmann, E.; Loizides, J. H.; Long, K. R.; Longhin, A.; Lontkovskyi, D.; Lukina, O. Yu.; ?u?niak, P.; Maeda, J.; Magill, S.; Makarenko, I.; Malka, J.; Mankel, R.; Margotti, A.; Marini, G.; Martin, J. F.; Mastroberardino, A.; Matsumoto, T.; Mattingly, M. C. K.; Melzer-Pellmann, I.-A.; Miglioranzi, S.; Mohamad Idris, F.; Monaco, V.; Montanari, A.; Morris, J. D.; Musgrave, B.; Nagano, K.; Namsoo, T.; Nania, R.; Nicholass, D.; Nigro, A.; Ning, Y.; Noor, U.; Notz, D.; Nowak, R. J.; Nuncio-Quiroz, A. E.; Oh, B. Y.; Okazaki, N.; Oliver, K.; Olkiewicz, K.; Onishchuk, Yu.; Ota, O.; Papageorgiu, K.; Parenti, A.; Paul, E.; Pawlak, J. M.; Pawlik, B.; Pelfer, P. G.; Pellegrino, A.; Perlanski, W.; Perrey, H.; Piotrzkowski, K.; Plucinski, P.; Pokrovskiy, N. S.; Polini, A.; P Roskuryakov, A. S.; Przybycie?, M.; Raval, A.; Reeder, D. D.; Reisert, B.; Ren, Z.; Repond, J.; Ri, Y. D.; Robertson, A.; Roloff, P.; Ron, E.; Rubinsky, I.; Ruspa, M.; Sacchi, R.; Salii, A.; Samson, U.; Sartorelli, G.; Savin, A. A.; Saxon, D. H.; Schioppa, M.; Schlenstedt, S.; Schleper, P.; Schmidke, W. B.; Schneekloth, U.; Schönberg, V.; Schörner-Sadenius, T.; Schwartz, J.; Sciulli, F.; Shcheglova, L. M.; Shehzadi, R.; Shimizu, S.; Singh, I.; Skillicorn, I. O.; Slomi?ski, W.; Smith, W. H.; Sola, V.; Solano, A.; Son, D.; Sosnovtsev, V.; Spiridonov, A.; Stadie, H.; Stanco, L.; Stern, A.; Stewart, T. P.; Stifutkin, A.; Stopa, P.; Suchkov, S.; Susinno, G.; Suszycki, L.; Sztuk, J.; Szuba, D.; Szuba, J.; Tapper, A. D.; Tassi, E.; Terrón, J.; Theedt, T.; Tiecke, H.; Tokushuku, K.; Tomalak, O.; Tomaszewska, J.; Tsurugai, T.; Turcato, M.; Tymieniecka, T.; Uribe-Estrada, C.; Vázquez, M.; Verbytskyi, A.; Viazlo, O.; Vlasov, N. N.; Volynets, O.; Walczak, R.; Wan Abdullah, W. A. T.; Whitmore, J. J.; Whyte, J.; Wiggers, L.; Wing, M.; Wlasenko, M.; Wolf, G.; Wolfe, H.; Wrona, K.; Yagües-Molina, A. A.; Yamada, S.; Yamazaki, Y.; Yoshida, R.; Youngman, C.; ?arnecki, A. A.; Zawiejski, L.; Zenaiev, O.; Zeuner, W.; Zhautykov, B. O.; Zhmak, N.; Zhou, C.; Zichichi, A.; Zolko, M.; Zotkin, D. S.; Zulkapli, Z.

2010-11-01

131

Diffractive Production of Jets and Weak Bosons, and Tests of Hard-Scattering Factorization  

E-print Network

We extract diffractive parton densities from diffractive, deep inelastic (DIS) ep data from the ZEUS experiment. Then we use these fits to predict the diffractive production of jets and of W's and Z's in p\\bar p collisions at the Tevatron. Although the DIS data require a hard quark density in the pomeron, we find fairly low rates for the Tevatron processes (a few percent of the inclusive cross section). This results from the combined effects of Q^{2} evolution and of a normalization of the parton densities to the data. The calculated rates for W production are generally consistent with the preliminary data from the Tevatron. However, the jet data from CDF with a ``Roman pot'' trigger are substantially lower than the results of our calculations; if confirmed, this would signal a breakdown of hard-scattering factorization.

Lyndon Alvero; John C. Collins; Juan Terron; Jim Whitmore

1997-01-24

132

Regulation of the Tyrosine Kinase Pyk2 by Calcium Is through Production of Reactive Oxygen Species in Cytotoxic T Lymphocytes*  

PubMed Central

Pyk2 was identified as a Ca2+-dependent kinase, however, the regulation of Pyk2 by Ca2+ in T cells remains controversial. We found that Ca2+ mobilization preferentially induced Pyk2 phosphorylation in cytotoxic T lymphocytes (CTL). Furthermore, Pyk2 phosphorylation in CTL was not absolutely Ca2+ dependent but relied on the strength of T cell receptor stimulation. Ionomycin-stimulated Pyk2 phosphorylation did not require calmodulin activity, because phosphorylation was not inhibited by the calmodulin inhibitor W7, and we detected no Ca2+-regulated association between Pyk2 and calmodulin. Ca2+-stimulated Pyk2 phosphorylation was dependent on Src-family kinase activity, even at the Pyk2 autophosphorylation site. We sought to identify a Ca2+-regulated pathway that could trigger Pyk2 phosphorylation in T cells and found that ionomycin stimulated the production of reactive oxygen species and an H2O2 scavenger inhibited ionomycin-induced Pyk2 phosphorylation. Additionally, H2O2 induced strong Erk activation and ionomycin-stimulated Pyk2 phosphorylation was Erk dependent. These data support the conclusion that Ca2+ mobilization induces the production of reactive oxygen species, which in turn activate the Erk pathway, leading to Src-family kinase-dependent Pyk2 phosphorylation. Our data demonstrate that Pyk2 is not a Ca2+-dependent kinase in T cells but instead, increased intracellular Ca2+ induces Pyk2 phosphorylation through production of reactive oxygen species. These findings are consistent with the possibility that Pyk2 acts as an early sensor of numerous extracellular signals that trigger a Ca2+ flux and/or reactive oxygen species to amplify tyrosine phosphorylation signaling events. PMID:20688918

Lysechko, Tara L.; Cheung, Samuel M. S.; Ostergaard, Hanne L.

2010-01-01

133

Azimuthal angle dependence of di-jet production in unpolarized hadron scattering  

SciTech Connect

We study the azimuthal asymmetry of back-to-back di-jet production in unpolarized hadron scattering, arising from the product of two Boer-Mulders functions, which describe the transverse spin distribution of quarks inside an unpolarized hadron. We find that there is a cos {delta}{phi} angular dependence of the di-jet, with {delta}{phi} the difference of the azimuthal angle of tow jets respectively. In the case of J{sub q}+J{sub q} production, we find that there is a color factor enhancement in the gluonic cross-section due to the multiple initial-/final-state interactions, compared with the result from the standard generalized parton model. We estimate the cos {delta}{phi} asymmetry of the total di-jet production at RHIC, showing that the color factor enhancement in the azimuthal asymmetric cross section of J{sub q}+J{sub q} production will reverse the sign of the asymmetry.

Lu Zhun; Schmidt, Ivan [Departamento de Fisica, Universidad Tecnica Federico Santa Maria, Valparaiso (Chile) and Center of Subatomic Physics, Valparaiso (Chile)

2009-08-04

134

Transient Influx of Nickel in Root Mitochondria Modulates Organic Acid and Reactive Oxygen Species Production in  

E-print Network

Transient Influx of Nickel in Root Mitochondria Modulates Organic Acid and Reactive Oxygen Species, Delaware 19711 Background: Mitochondria are important targets of metal toxicity. Results: Our data confirms that nickel is localized in the mitochondria of Alyssum murale root epidermal cells. Conclusion

Sparks, Donald L.

135

Effect of resveratrol, a natural polyphenolic compound, on reactive oxygen species and prostaglandin production  

Microsoft Academic Search

Resveratrol is a natural molecule with antioxidant action. Moreover, resveratrol is also considered to be a molecule with anti-inflammatory action, an effect attributed to suppression of prostaglandin (PG) biosynthesis. The aim of the present study was to investigate the effects of resveratrol, a polyphenol present in most red wines, on reactive oxygen species formation as well as on arachidonic acid

Javier Martinez; Juan J Moreno

2000-01-01

136

Production and characterization of mouse monoclonal antibodies reactive to Chikungunya envelope E2 glycoprotein  

Microsoft Academic Search

Chikungunya fever is an arbovirosis of major impact in public health in Asia and Africa. Chikungunya (CHIK) virus is member of the genus Alphavirus and belongs to the Semliki Forest (SF) antigenic complex. We describe for the first time a panel of monoclonal antibodies (MAbs) reactive to CHIK envelope E2 glycoprotein. For the screening of E2-specific MAbs, we expressed a

Anne-Claire Bréhin; Laetitia Rubrecht; Martha Erika Navarro-Sanchez; Valérie Maréchal; Marie-Pascale Frenkiel; Priscilla Lapalud; Daniel Laune; Amadou Alpha Sall; Philippe Desprès

2008-01-01

137

The Alternative Oxidase Lowers Mitochondrial Reactive Oxygen Production in Plant Cells  

Microsoft Academic Search

Besides the cytochrome c pathway, plant mitochondria have an alternative respiratory pathway that is comprised of a single homodimeric protein, alternative oxidase (AOX). Transgenic cultured tobacco cells with altered levels of AOX were used to test the hypothesis that the alternative pathway in plant mitochondria functions as a mechanism to decrease the formation of reactive oxygen species (ROS) produced during

Denis P. Maxwell; Yong Wang; Lee McIntosh

1999-01-01

138

Production of reactive oxygen species in mitochondria of HeLa cells under oxidative stress  

Microsoft Academic Search

Mitochondria can be a source of reactive oxygen species (ROS) and a target of oxidative damage during oxidative stress. In this connection, the effect of photodynamic treatment (PDT) with Mitotracker Red (MR) as a mitochondria-targeted photosensitizer has been studied in HeLa cells. It is shown that MR produces both singlet oxygen and superoxide anion upon photoactivation and causes photoinactivation of

Boris V. Chernyak; Denis S. Izyumov; Konstantin G. Lyamzaev; Alina A. Pashkovskaya; Olga Y. Pletjushkina; Yuri N. Antonenko; Dmitrii V. Sakharov; Karel W. A. Wirtz; Vladimir P. Skulachev

2006-01-01

139

Synthesis and evaluation of chalcone derivatives as inhibitors of neutrophils' chemotaxis, phagocytosis and production of reactive oxygen species.  

PubMed

Inhibitory effects on neutrophils' chemotaxis, phagocytosis and production of reactive oxygen species (ROS) are among the important targets in developing anti-inflammatory agents and immunosuppressants. Eight series of chalcone derivatives including five newly synthesized series were assessed for their inhibitory effects on chemotaxis, phagocytosis and ROS production in human polymorphonuclear neutrophils (PMNs). Inhibition of PMNs' chemotaxis and phagocytosis abilities were investigated using the Boyden chamber technique and the Phagotest kit, respectively, while ROS production was evaluated using luminol- and lucigenin-based chemiluminescence assay. The new derivatives (4d and 8d), which contain 4-methylaminoethanol functional group were active in all the assays performed. It was also observed that some of the compounds were active in inhibiting chemotaxis while others suppressed phagocytosis and ROS production. The information obtained gave new insight into chalcone derivatives with the potential to be developed as immunomodulators. PMID:24433224

Bukhari, Syed N A; Tajuddin, Yasmin; Benedict, Vannessa J; Lam, Kok W; Jantan, Ibrahim; Jalil, Juriyati; Jasamai, Malina

2014-02-01

140

REACTIONS OF PEROXYNITRITE WITH URIC ACID: FORMATION OF REACTIVE INTERMEDIATES, ALKYLATED PRODUCTS AND TRIURET, AND IN VIVO PRODUCTION OF TRIURET UNDER CONDITIONS OF OXIDATIVE STRESS  

PubMed Central

Hyperuricemia is associated with hypertension, metabolic syndrome, preeclampsia, cardiovascular disease and renal disease, all conditions associated with oxidative stress. We hypothesized that uric acid, a known antioxidant, might become prooxidative following its reaction with oxidants; and, thereby contribute to the pathogenesis of these diseases. Uric acid and 1,3-15N2-uric acid were reacted with peroxynitrite in different buffers and in the presence of alcohols, antioxidants and in human plasma. The reaction products were identified using liquid chromatography-mass spectrometry (LC-MS) analyses. The reactions generate reactive intermediates that yielded triuret as their final product. We also found that the antioxidant, ascorbate, could partially prevent this reaction. Whereas triuret was preferentially generated by the reactions in aqueous buffers, when uric acid or 1,3-15N2-uric acid was reacted with peroxynitrite in the presence of alcohols, it yielded alkylated alcohols as the final product. By extension, this reaction can alkylate other biomolecules containing OH groups and others containing labile hydrogens. Triuret was also found to be elevated in the urine of subjects with preeclampsia, a pregnancy-specific hypertensive syndrome that is associated with oxidative stress, whereas very little triuret is produced in normal healthy volunteers. We conclude that under conditions of oxidative stress, uric acid can form reactive intermediates, including potential alkylating species, by reacting with peroxynitrite. These reactive intermediates could possibly explain how uric acid contributes to the pathogenesis of diseases such as the metabolic syndrome and hypertension. PMID:19219741

Gersch, Christine; Palii, Sergiu P.; Imaram, Witcha; Kim, Kyung Mee; Karumanchi, S. Ananth; Angerhofer, Alexander; Johnson, Richard J.; Henderson, George N.

2009-01-01

141

PROBING REACTIVITY OF DISSOLVED ORGANIC MATTER FOR DISINFECTION BY-PRODUCT FORMATION USING XAD-8 RESIN ADSORPTION AND ULTRAFILTRATION FRACTIONATION. (R828045)  

EPA Science Inventory

The disinfection by-product (DBP) reactivity (yield and speciation upon reaction with chlorine) of dissolved organic matter (DOM) isolated from two surface waters was investigated. The source waters, each having significantly different specific ultraviolet absorbance (SUVA...

142

Cytokines and C-Reactive Protein Production in Hip-Fracture-Operated Elderly Patients  

Microsoft Academic Search

Background. The study aim was to determine the kinetics of serum pro- and anti-inflammatory cytokines and C-reactive protein (CRP) in hip-fracture patients over a month postfracture, and their relationship to postoperative (postop) complications and cognitive level. Methods. Forty-one elderly hip-fracture patients were prospectively followed. Serum was obtained during the first 10 hours postfracture and presurgery, 48-60 hours postop, 7 and

Yichayaou Beloosesky; David Hendel; Avraham Weiss; Avital Hershkovitz; Joseph Grinblat; Anatoly Pirotsky; Vivian Barak

2007-01-01

143

Increased Adhesion Molecules Expression and Production of Reactive Oxygen Species in Leukocytes of Sleep Apnea Patients  

Microsoft Academic Search

Obstructive sleep apnea (OSA) is associated with increased cardio- vascular morbidity and mortality. Free radicals and adhesion mole- cules were implicated in the pathogenesis of atherosclerosis lead- ing to cardiovascular disorders. Therefore, we investigated the link between CD15, CD11c, CD11b, and CD64 expression on leukocytes and their ability to generate reactive oxygen species (ROS) in pa- tients with OSA and

LARISSA DYUGOVSKAYA; PERETZ LAVIE; LENA LAVIE

144

Measurement of D ± production in deep inelastic ep scattering with the ZEUS detector at HERA  

NASA Astrophysics Data System (ADS)

Charm production in deep inelastic ep scattering was measured with the ZEUS detector using an integrated luminosity of 354 pb-1. Charm quarks were identified by reconstructing D ± mesons in the D ± ? K ??±?± decay channel. Lifetime information was used to reduce combinatorial background substantially. Differential cross sections were measured in the kinematic region 5 < Q 2 < 1000 GeV2, 0 .02 < y < 0 .7, 1 .5 < p T ( D ±) < 15 GeV and | ?( D ±)| < 1 .6, where Q 2 is the photon virtuality, y is the inelasticity, and p T ( D ±) and ?( D ±) are the transverse momentum and the pseudorapidity of the D ± meson, respectively. Next-to-leading-order QCD predictions are compared to the data. The charm contribution, F_2^{{coverline{c}}} , to the proton structure-function F 2 was extracted.

Abramowicz, H.; Abt, I.; Adamczyk, L.; Adamus, M.; Aggarwal, R.; Antonelli, S.; Antonioli, P.; Antonov, A.; Arneodo, M.; Arslan, O.; Aushev, V.; Aushev, Y.; Bachynska, O.; Bamberger, A.; Barakbaev, A. N.; Barbagli, G.; Bari, G.; Barreiro, F.; Bartosik, N.; Bartsch, D.; Basile, M.; Behnke, O.; Behr, J.; Behrens, U.; Bellagamba, L.; Bertolin, A.; Bhadra, S.; Bindi, M.; Blohm, C.; Bokhonov, V.; Bold, T.; Boos, E. G.; Borras, K.; Boscherini, D.; Bot, D.; Brock, I.; Brownson, E.; Brugnera, R.; Brümmer, N.; Bruni, A.; Bruni, G.; Brzozowska, B.; Bussey, P. J.; Bylsma, B.; Caldwell, A.; Capua, M.; Carlin, R.; Catterall, C. D.; Chekanov, S.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cifarelli, L.; Cindolo, F.; Contin, A.; Cooper-Sarkar, A. M.; Coppola, N.; Corradi, M.; Corriveau, F.; Costa, M.; D'Agostini, G.; Corso, F. Dal; del Peso, J.; Dementiev, R. K.; De Pasquale, S.; Derrick, M.; Devenish, R. C. E.; Dobur, D.; Dolgoshein, B. A.; Dolinska, G.; Doyle, A. T.; Drugakov, V.; Durkin, L. S.; Dusini, S.; Eisenberg, Y.; Ermolov, P. F.; Eskreys, A.; Fang, S.; Fazio, S.; Ferrando, J.; Ferrero, M. I.; Figiel, J.; Foster, B.; Gach, G.; Galas, A.; Gallo, E.; Garfagnini, A.; Geiser, A.; Gialas, I.; Gizhko, A.; Gladilin, L. K.; Gladkov, D.; Glasman, C.; Gogota, O.; Golubkov, Yu. A.; Göttlicher, P.; Grabowska-Bold, I.; Grebenyuk, J.; Gregor, I.; Grigorescu, G.; Grzelak, G.; Gueta, O.; Guzik, M.; Gwenlan, C.; Haas, T.; Hain, W.; Hamatsu, R.; Hart, J. C.; Hartmann, H.; Hartner, G.; Hilger, E.; Hochman, D.; Hori, R.; Hüttmann, A.; Ibrahim, Z. A.; Iga, Y.; Ingbir, R.; Ishitsuka, M.; Iudin, A.; Jakob, H.-P.; Januschek, F.; Jones, T. W.; Jüngst, M.; Kadenko, I.; Kahle, B.; Kananov, S.; Kanno, T.; Karshon, U.; Karstens, F.; Katkov, I. I.; Kaur, M.; Kaur, P.; Keramidas, A.; Khein, L. A.; Kim, J. Y.; Kisielewska, D.; Kitamura, S.; Klanner, R.; Klein, U.; Koffeman, E.; Kondrashova, N.; Kononenko, O.; Kooijman, P.; Korol, Ie.; Korzhavina, I. A.; Kotanski, A.; Kötz, U.; Kovalchuk, N.; Kowalski, H.; Kuprash, O.; Kuze, M.; Lee, A.; Levchenko, B. B.; Levy, A.; Libov, V.; Limentani, S.; Ling, T. Y.; Lisovyi, M.; Lobodzinska, E.; Lohmann, W.; Löhr, B.; Lohrmann, E.; Long, K. R.; Longhin, A.; Lontkovskyi, D.; Lukina, O. Yu.; Maeda, J.; Magill, S.; Makarenko, I.; Malka, J.; Mankel, R.; Margotti, A.; Marini, G.; Martin, J. F.; Mastroberardino, A.; Mattingly, M. C. K.; Melzer-Pellmann, I.-A.; Mergelmeyer, S.; Miglioranzi, S.; Idris, F. Mohamad; Monaco, V.; Montanari, A.; Morris, J. D.; Mujkic, K.; Musgrave, B.; Nagano, K.; Namsoo, T.; Nania, R.; Nigro, A.; Ning, Y.; Nobe, T.; Notz, D.; Nowak, R. J.; Nuncio-Quiroz, A. E.; Oh, B. Y.; Okazaki, N.; Olkiewicz, K.; Onishchuk, Yu.; Papageorgiu, K.; Parenti, A.; Paul, E.; Pawlak, J. M.; Pawlik, B.; Pelfer, P. G.; Pellegrino, A.; Perlanski, W.; Perrey, H.; Piotrzkowski, K.; Plucinski, P.; Pokrovskiy, N. S.; Polini, A.; Proskuryakov, A. S.; Przybycien, M.; Raval, A.; Reeder, D. D.; Reisert, B.; Ren, Z.; Repond, J.; Ri, Y. D.; Robertson, A.; Roloff, P.; Rubinsky, I.; Ruspa, M.; Sacchi, R.; Samson, U.; Sartorelli, G.; Savin, A. A.; Saxon, D. H.; Schioppa, M.; Schlenstedt, S.; Schleper, P.; Schmidke, W. B.; Schneekloth, U.; Schönberg, V.; Schörner-Sadenius, T.; Schwartz, J.; Sciulli, F.; Shcheglova, L. M.; Shehzadi, R.; Shimizu, S.; Singh, I.; Skillicorn, I. O.; Slominski, W.; Smith, W. H.; Sola, V.; Solano, A.; Son, D.; Sosnovtsev, V.; Spiridonov, A.; Stadie, H.; Stanco, L.; Stefaniuk, N.; Stern, A.; Stewart, T. P.; Stifutkin, A.; Stopa, P.; Suchkov, S.; Susinno, G.; Suszycki, L.; Sztuk-Dambietz, J.; Szuba, D.; Szuba, J.; Tapper, A. D.; Tassi, E.; Terrón, J.; Theedt, T.; Tiecke, H.; Tokushuku, K.; Tomaszewska, J.; Trofymov, A.; Trusov, V.; Tsurugai, T.; Turcato, M.; Turkot, O.; Tymieniecka, T.; Vázquez, M.; Verbytskyi, A.; Viazlo, O.; Vlasov, N. N.; Walczak, R.; Abdullah, W. A. T. Wan; Whitmore, J. J.; Wichmann, K.; Wiggers, L.; Wing, M.; Wlasenko, M.; Wolf, G.; Wolfe, H.; Wrona, K.; Yagües-Molina, A. G.; Yamada, S.; Yamazaki, Y.; Yoshida, R.; Youngman, C.; Zakharchuk, N.; ?arnecki, A. F.; Zawiejski, L.; Zenaiev, O.; Zeuner, W.; Zhautykov, B. O.; Zhmak, N.; Zichichi, A.; Zolkapli, Z.; Zotkin, D. S.

2013-05-01

145

Study of ?(1385) and ?(1321) hyperon and antihyperon production in deep inelastic muon scattering  

E-print Network

Large samples of \\Lambda, \\Sigma(1385) and \\Xi(1321) hyperons produced in deep-inelastic muon scattering off a ^6LiD target were collected with the COMPASS experimental setup at CERN. The relative yields of \\Sigma(1385)^+, \\Sigma(1385)^-, \\bar{\\Sigma}(1385)^-, \\bar{\\Sigma}(1385)^+, \\Xi(1321)^-, and \\bar{\\Xi}(1321)^+ hyperons decaying into \\Lambda(\\bar{\\Lambda})\\pi were measured. The heavy hyperon to \\Lambda and heavy antihyperon to \\bar{\\Lambda} yield ratios were found to be in the range 3.8% to 5.6% with a relative uncertainty of about 10%. They were used to tune the parameters relevant for strange particle production of the LEPTO Monte Carlo generator.

C. Adolph; M. Alekseev; V. Yu. Alexakhin; Yu. Alexandrov; G. D. Alexeev; A. Amoroso; A. Austregesilo; B. Badelek; F. Balestra; J. Barth; G. Baum; Y. Bedfer; A. Berlin; J. Bernhard; R. Bertini; K. Bicker; J. Bieling; R. Birsa; J. Bisplinghoff; P. Bordalo; F. Bradamante; C. Braun; A. Bravar; A. Bressan; M. Buechele; E. Burtin; L. Capozza; M. Chiosso; S. U. Chung; A. Cicuttin; M. L. Crespo; S. Dalla Torre; S. S. Dasgupta; S. Dasgupta; O. Yu. Denisov; S. V. Donskov; N. Doshita; V. Duic; W. Duennweber; M. Dziewiecki; A. Efremov; C. Elia; P. D. Eversheim; W. Eyrich; M. Faessler; A. Ferrero; A. Filin; M. Finger; M. Finger jr.; H. Fischer; C. Franco; N. du Fresne von Hohenesche; J. M. Friedrich; V. Frolov; R. Garfagnini; F. Gautheron; O. P. Gavrichtchouk; S. Gerassimov; R. Geyer; M. Giorgi; I. Gnesi; B. Gobbo; S. Goertz; S. Grabmueller; A. Grasso; B. Grube; R. Gushterski; A. Guskov; T. Guthoerl; F. Haas; D. von Harrach; F. H. Heinsius; F. Herrmann; C. Hess; F. Hinterberger; Ch. Hoeppner; N. Horikawa; N. d'Hose; S. Huber; S. Ishimoto; Yu. Ivanshin; T. Iwata; R. Jahn; V. Jary; P. Jasinski; R. Joosten; E. Kabuss; D. Kang; B. Ketzer; G. V. Khaustov; Yu. A. Khokhlov; Yu. Kisselev; F. Klein; K. Klimaszewski; J. H. Koivuniemi; V. N. Kolosov; K. Kondo; K. Koenigsmann; I. Konorov; V. F. Konstantinov; A. M. Kotzinian; O. Kouznetsov; M. Kraemer; Z. V. Kroumchtein; N. Kuchinski; F. Kunne; K. Kurek; R. P. Kurjata; A. A. Lednev; A. Lehmann; S. Levorato; J. Lichtenstadt; A. Maggiora; A. Magnon; N. Makke; G. K. Mallot; A. Mann; C. Marchand; A. Martin; J. Marzec; H. Matsuda; T. Matsuda; G. Meshcheryakov; W. Meyer; T. Michigami; Yu. V. Mikhailov; Y. Miyachi; A. Morreale; A. Nagaytsev; T. Nagel; F. Nerling; S. Neubert; D. Neyret; V. I. Nikolaenko; J. Novy; W. -D. Nowak; A. S. Nunes; A. G. Olshevsky; M. Ostrick; R. Panknin; D. Panzieri; B. Parsamyan; S. Paul; G. Piragino; S. Platchkov; J. Pochodzalla; J. Polak; V. A. Polyakov; J. Pretz; M. Quaresma; C. Quintans; S. Ramos; G. Reicherz; E. Rocco; V. Rodionov; E. Rondio; N. S. Rossiyskaya; D. I. Ryabchikov; V. D. Samoylenko; A. Sandacz; M. G. Sapozhnikov; S. Sarkar; I. A. Savin; G. Sbrizzai; P. Schiavon; C. Schill; T. Schlueter; A. Schmidt; K. Schmidt; L. Schmitt; H. Schmieden; K. Schoenning; S. Schopferer; M. Schott; O. Yu. Shevchenko; L. Silva; L. Sinha; S. Sirtl; S. Sosio; F. Sozzi; A. Srnka; L. Steiger; M. Stolarski; M. Sulc; R. Sulej; H. Suzuki; P. Sznajder; S. Takekawa; J. Ter Wolbeek; S. Tessaro; F. Tessarotto; F. Thibaud; S. Uhl; I. Uman; M. Vandenbroucke; M. Virius; L. Wang; T. Weisrock; M. Wilfert; R. Windmolders; W. Wislicki; H. Wollny; K. Zaremba; M. Zavertyaev; E. Zemlyanichkina; N. Zhuravlev; M. Ziembicki

2013-04-03

146

Production and characterization of mouse monoclonal antibodies reactive to Chikungunya envelope E2 glycoprotein.  

PubMed

Chikungunya fever is an arbovirosis of major impact in public health in Asia and Africa. Chikungunya (CHIK) virus is member of the genus Alphavirus and belongs to the Semliki Forest (SF) antigenic complex. We describe for the first time a panel of monoclonal antibodies (MAbs) reactive to CHIK envelope E2 glycoprotein. For the screening of E2-specific MAbs, we expressed a recombinant soluble CHIK E2 protein in Drosophila S2 cells. Analyzed by immunological methods, MAbs 3C3, 3E4, and 8A4 were selected on the basis of their reactivity. Their epitopes are located to the outer surface of CHIK virion. These MAbs have no cross reactivity with related members of SF antigenic complex with the notable exception of Igbo-Ora virus. Anti-CHIK E2 MAbs 3C3, 3E4, and 8A4 should be helpful for studying the biology of CHIK virus and pathogenesis of disease. The combination of 8A4 and 3E4 is suitable for developing a specific antigen-capture ELISA. PMID:17949772

Bréhin, Anne-Claire; Rubrecht, Laetitia; Navarro-Sanchez, Martha Erika; Maréchal, Valérie; Frenkiel, Marie-Pascale; Lapalud, Priscilla; Laune, Daniel; Sall, Amadou Alpha; Desprès, Philippe

2008-02-01

147

Controlling reactivity of nanoporous catalyst materials by tuning reaction product-pore interior interactions: Statistical mechanical modeling  

SciTech Connect

Statistical mechanical modeling is performed of a catalytic conversion reaction within a functionalized nanoporous material to assess the effect of varying the reaction product-pore interior interaction from attractive to repulsive. A strong enhancement in reactivity is observed not just due to the shift in reaction equilibrium towards completion but also due to enhanced transport within the pore resulting from reduced loading. The latter effect is strongest for highly restricted transport (single-file diffusion), and applies even for irreversible reactions. The analysis is performed utilizing a generalized hydrodynamic formulation of the reaction-diffusion equations which can reliably capture the complex interplay between reaction and restricted transport.

Wang, Jing [Ames Laboratory; Ackerman, David M. [Ames Laboratory; Lin, Victor S.-Y. [Ames Laboratory; Pruski, Marek [Ames Laboratory; Evans, James W. [Ames Laboratory

2013-04-02

148

[Roles of reactive oxygen species in Streptomyces pactum Act12-induced tanshinone production in Salvia miltiorrhiza hairy roots].  

PubMed

Our previous research indicated that the Streptomyces pactum Act12 (Act12) had a certain promotional effect on tanshinone accumulation and up-regulated the expression of genes 3-hydroxy-3-methyglutaryl-CoA reductase (HMGR) and 1-deoxy-d-xylulose-5-phosphate reductoisomerase (DXR) in Salvia miltiorrhiza hairy roots. This study focuses on the roles of reactive oxygen species in S. pactum Act12-induced tanshinone production in S. miltiorrhiza hairy roots. The 4% Act12, 4% Act12 + CAT and 4% Act12 + SOD were added to S. miltiorrhiza hairy root and subcultured for 21 days, the dry weight, contents of reactive oxygen species, contents of tanshinones and expression of HMGR and DXR were determined at different harvest-time. The generation of reactive oxygen species (ROS) in S. miltiorrhiza hairy roots was triggered by 4% Act12 treatment. The relative expressions of genes HMGR and DXR in 4% Act12 treatment were 32.4 and 4.8-fold higher than those in the control. And the total tanshinone in the hairy roots was 10.2 times higher than that of the control. The CAT and SOD could significantly inhibit the ROS accumulation and relative expressions of genes HMGR and DXR in 4% Act12 treatment, which induced the total tanshinone content was decreased by 74.6% comparing with the 4% Act12 treatment. ROS mediated Act12-induced tanshinone production. The Act12 may be via the ROS signal channel to activate the tanshinone biosynthesis pathways. Thereby the tanshinon content in hairy roots was increased. PMID:25272827

Yan, Yan; Zhao, Xin; Zhang, Shun-Cang; Liu, Yan; Liang, Zong-Suo

2014-06-01

149

Structure-reactivity relationships of flavan-3-ols on product generation in aqueous glucose/glycine model systems.  

PubMed

Ring structure-reactivity relationships of three flavan-3-ols [epicatechin (EC), epicatechin gallate (ECG), and epigallocatechin gallate (EGCG)] and three simple phenolic compounds (1,3,5-trihydroxybenzene, 1,2,3-trihydroxybenzene, and methylgallate as the analogous individual A, B, and C benzene rings of EGCG) on product generation in an aqueous glucose-glycine reaction model system (125 degrees C and 30 min) were investigated. The addition of EC, ECG, or EGCG to a glucose-glycine model was reported to similarly significantly reduce the formation of pyrazine, methyl-substituted pyrazines, and cyclotene. All three flavan-3-ols were also reported to generate phenolic-C2, C3, C4, and C6 sugar fragment adducts and to statistically reduce the concentration of glyoxal, glycolaldehyde, methylglyoxal, hydroxyacetone, diacetyl, acetoin, and 3-deoxyglucosone during the reaction time course, except for the EGCG reaction where 3-deoxyglucosone was not statistically different from the control after 20 min. For the simple phenolic compounds, methylgallate followed by 1,2,3-trihydroxybenzene was the least reactive, while 1,3,5-trihydroxybenzene was reported as the most reactive phenolic structure for quenching or reducing the concentration of the alpha-hydroxy- and alpha-dicarbonyl sugar fragments during the reaction time course. These results imply that the main mechanism flavan-3-ols reduced product generation was phenolic-sugar fragment carbonyl trapping reactions primarily on the A ring (the meta-polyhydroxylated benzene ring) or not due to the alteration of the reaction reduction potential. PMID:17394338

Noda, Yuko; Peterson, Devin G

2007-05-01

150

The impact of dehydration rate on the production and cellular location of reactive oxygen species in an aquatic moss  

PubMed Central

Background and Aims The aquatic moss Fontinalis antipyretica requires a slow rate of dehydration to survive a desiccation event. The present work examined whether differences in the dehydration rate resulted in corresponding differences in the production of reactive oxygen species (ROS) and therefore in the amount of cell damage. Methods Intracellular ROS production by the aquatic moss was assessed with confocal laser microscopy and the ROS-specific chemical probe 2,7-dichlorodihydrofluorescein diacetate. The production of hydrogen peroxide was also quantified and its cellular location was assessed. Key Results The rehydration of slowly dried cells was associated with lower ROS production, thereby reducing the amount of cellular damage and increasing cell survival. A high oxygen consumption burst accompanied the initial stages of rehydration, perhaps due to the burst of ROS production. Conclusions A slow dehydration rate may induce cell protection mechanisms that serve to limit ROS production and reduce the oxidative burst, decreasing the number of damaged and dead cells due upon rehydration. PMID:22875812

Cruz de Carvalho, Ricardo; Catala, Myriam; Marques da Silva, Jorge; Branquinho, Cristina; Barreno, Eva

2012-01-01

151

Production, characterization, and cross-reactivity studies of monoclonal antibodies against the coccidiostat nicarbazin.  

PubMed

A cELISA was developed for the coccidiostat nicarbazin. On the basis of previous computer-assisted molecular modeling studies, p-nitrosuccinanilic acid (PNA-S) was selected as a hapten to produce antibodies to 4,4'-dinitrocarbanilide (DNC), the active component of the coccidiostat nicarbazin. Synthesis is described for the hapten [p-nitro-cis-1,2-cyclohexanedicarboxanilic acid (PNA-C)] used in a BSA conjugate as a plate coating antigen. Monoclonal antibodies (Mabs) were isolated that compete with nicarbazin, having IgM(kappa) isotype. Because of the lack of water solubility of nicarbazin, N,N-dimethylformamide (DMF) (3%, v/v) and acetonitrile (ACN) (10%, v/v) were added to the assay buffer to achieve solubility of nicarbazin and related compounds. The Nic 6 Mabs had an IC(35) value for nicarbazin of 0.92 nmol/mL, with a limit of detection of 0.33 nmol/mL. Nic 6 exhibited high cross-reactivity for PNA-S and PNA-C, and 3-nitrophenol, 4-nitrophenol, and 1-(4-chlorophenyl)-3-(4-nitrophenyl) urea. However, Nic 6 had little or no cross-reactivity with 15 other related compounds. PMID:11599986

Beier, R C; Ripley, L H; Young, C R; Kaiser, C M

2001-10-01

152

Production of monoclonal antibodies that recognize specific and cross-reactive antigens of Fusobacterium nucleatum.  

PubMed Central

Monoclonal antibodies (MAbs) against the cell surface antigens of Fusobacterium nucleatum 263 were obtained by fusion of murine myeloma cells (P3-NSI/1-Ag4-1) with the splenocytes of BALB/c mice immunized with whole cells of F. nucleatum 263. Screening was performed using an enzyme-linked immunosorbent assay (ELISA) against the immunizing strain, F. nucleatum 263. Further selection was done using a bacterial panel consisting of Bacteroides, Actinomyces, Streptococcus, Fusobacterium, and Escherichia species. Twelve MAbs were selected on the basis of this screening procedure, seven of which reacted specifically with F. nucleatum 263. Two reacted with F. nucleatum 263 and ATCC 25586, and three reacted with F. nucleatum 263, ATCC 25586, and UQD-003 (a clinical isolate) and also cross-reacted with Fusobacterium russii ATCC 25533. The selected MAbs were then further characterized by absorption experiments with suspensions of intact whole bacterial cells, and the residual binding activity of the supernatants was determined in an ELISA. To determine whether the MAbs reacted with the same or different epitopes, pairs of MAbs were reacted together and independently in a checkerboard manner in an ELISA. The additive or nonadditive nature of the reactivity was determined. A competitive inhibition assay was performed using one labeled and selected unlabeled MAbs. The results of these experiments suggested some epitope sharing among the selected MAbs that reacted with a specific antigen on F. nucleatum and also shared cross-reactive antigens with the three strains of F. nucleatum and F. russii. PMID:3818097

Bird, P S; Seymour, G J

1987-01-01

153

Reactive oxygen production by cultured rat glomerular mesangial cells during phagocytosis is associated with stimulation of lipoxygenase activity  

PubMed Central

To investigate the phagocytic capability of glomerular mesangial cells and the biochemical events associated with phagocytosis, rat cultured mesangial cells were incubated in the presence of opsonized zymosan (STZ) and production of reactive-oxygen species and lipoxygenase products were determined. Mesangial cells were identified on the basis of morphologic (presence of microfilaments and pattern of staining by an anti-myosin antiserum) and physiologic (contractile activity in response to angiotensin II) characteristics. No contamination by esterase-positive cells was observed. Electron microscopy revealed that the phagocytic process started after 5 min of incubation, and affected approximately 50% of the cells. Superoxide anion (.O2-) and hydrogen peroxide (H2O2) generation by mesangial cells exposed to STZ increased with time and STZ concentration. Cells incubated with zymosan particles treated with heated serum produced undetectable amounts of .O2- and 6 times less H2O2 than cells exposed to STZ. Pretreatment by cytochalasin B produced a marked decrease in STZ-stimulated production of reactive oxygen species. [3H]Arachidonic acid was incorporated into mesangial cell phospholipids and its release and conversion into monohydroxyeicosatetraenoic acids (HETE) was measured by radiometric high performance liquid chromatography (HPLC). Incubation with STZ markedly stimulated the release of arachidonic acid from its phospholipid stores and its transformation into 11-, 12-, and 15-HETE. Lipoxygenase inhibitors inhibited STZ-stimulated H2O2 production, whereas they did not modify the phagocytic process as shown by the absence of any effect on the uptake of 125I-STZ by the mesangial cells. This study demonstrates that a high percentage of rat cultured mesangial cells phagocytose opsonized particles. The phagocytic process results in an oxidative burst that appears to be dependent on stimulation of the lipoxygenase pathway. PMID:6315851

1983-01-01

154

Inclusive Single Hadron Production in Neutral Current Deep-Inelastic Scattering at Next-to-Leading Order  

E-print Network

A study of inclusive production of single hadrons with finite transverse momentum in neutral current deep-inelastic scattering has been carried out. Cross sections have been calculated using perturbative Quantum Chromodynamics at next-to-leading order and compared to HERA data. Predictions for light charged hadron production data were also calculated for large values of Q^2 to show the possible effects of the Z-boson exchange.

Carlos Sandoval

2009-08-06

155

L-Arginine-Dependent Production of a Reactive Nitrogen Intermediate by Macrophages of a Uricotelic Species  

Microsoft Academic Search

resulted in significant nitrite production, while maximum levels of nitrite production were obtained using ?'0.5 ?i.g\\/ml LPS and ?0.4 mM L-argmnmne. These results indicate that chicken macrophages can produce RNIs. This production is dependent upon activation and is influenced by local L-arginine concentration. Moreover, because the chicken does not possess the abilityto synthesize arginine and has an absolute nutritional requirement

Yen-Jen Sung; Joseph H. Hotchkiss; Richard E. Austic; Rodney R. Dietert

1991-01-01

156

Chemical pneumonitis and subsequent reactive airways dysfunction syndrome after a single exposure to a household product: a case report  

PubMed Central

Introduction Household products are usually safe to use. Adverse events arising from their use are mostly reported in patients with pre-existing atopy or pulmonary problems and usually only after a prolonged exposure to such products. We report the case of a patient with no prior problems who developed significant side effects from a single exposure to a domestic product. Case presentation A 43-year-old Caucasian American man, previously in good health, used a domestic aerosol product called 'Stand N' Seal "Spray-On" Grout Sealer' in an enclosed room in his house. The product contained n-butyl acetate (<5%), propane (10%), isobutane (<5%), C8-C9 petroleum hydrocarbon solvent (80%), a fluoropolymer resin and a solvent. Within a few hours of exposure to the sealant, he developed rapidly progressive shortness of breath and a severe non-productive cough. By the time he reached the emergency room he was severely hypoxic. A diagnosis of chemical pneumonitis was made based on the clinical scenario and the diffuse infiltrates on the computer tomography scan. With supportive therapy, his condition improved and he was discharged from the hospital. However, he continued to have symptoms of intermittent cough and shortness of breath in response to strong odours, fumes, cold air and exertion even after his chest radiograph had normalized. Three months later, bronchial hyper-responsiveness was documented by a methacholine inhalation test and a diagnosis of reactive airways dysfunction syndrome was made. The patient was started on high-dose inhaled steroids and his symptoms improved. The mechanism of toxicity and determination of the exact agent responsible is still under investigation. Conclusion A household product may still prove unsafe to use even after it has gone through vigorous testing and approval processes. Even healthy individuals are susceptible to adverse outcomes after a brief exposure. Extra precautions should be taken when using any chemical product at home. PMID:19946590

2009-01-01

157

Reactive transport modelling of the interaction of fission product ground contamination with alkaline and cementitious leachates  

Microsoft Academic Search

The fission products Cs-137 and Sr-90 are amongst the most common radionuclides occurring in ground contamination at the UK civil nuclear sites. Such contamination is often associated with alkaline liquids and the mobility of these fission products may be affected by these chemical conditions. Similar geochemical effects may also result from cementitious leachate associated with building foundations and the use

S. Kwong; J. Small

2007-01-01

158

Inhibition of the production of reactive oxygen species in mouse peritoneal neutrophils by millimeter wave radiation in the near and far field zones of the radiator  

Microsoft Academic Search

Using the luminol-dependent chemiluminescence technique effects of a low-intensity electromagnetic field (EMF) of extremely high frequency of the production of reactive oxygen species (ROS) by mouse peritoneal neutrophils was studied. The neutrophils were activated by opsonized zymosan. It was found that the EMF inhibits the ROS production by the neutrophils. However, in the near field zone of the channel radiator

A. B. Gapeyev; V. G. Safronova; N. K. Chemeris; E. E. Fesenko

1997-01-01

159

Measurement of internal jet structure in dijet production in deep-inelastic scattering at HERA  

NASA Astrophysics Data System (ADS)

Internal jet structure in dijet production in deep-inelastic scattering is measured with the H1 detector at HERA. Jets with transverse energies ET,Breit > 5 GeV are selected in the Breit frame employing k? and cone jet algorithms. In the kinematic region of ssquared momentum transfers 10 < Q2 ? s 120 GeV 2 and Bjorken- x values 2 < 10 -4 ? xBj ? 8 × 10 -3, jet shapes and subjet multiplicities are measured as a function of a resolution parameter. Distributions of both observables are corrected for detector effects and presented as functions of the transverse jet energy and jet pseudo-rapidity. Dependences of the jet shape and the average number of subjets on the transverse energy and the pseudo-rapidity of the jet are observed. With increasing transverse jet energies and decreasing pseudo-rapidities, i.e. towards the photon hemisphere, the jets are more collimated. QCD models give a fair description of the data.

Adloff, C.; Andreev, V.; Andrieu, B.; Arkadov, V.; Astvatsatourov, A.; Ayyaz, I.; Babaev, A.; Bähr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Bassler, U.; Bate, P.; Beglarian, A.; Behnke, O.; Behrend, H.-J.; Beier, C.; Belousov, A.; Berger, Ch.; Bernardi, G.; Berndt, T.; Bertrand-Coremans, G.; Biddulph, P.; Bizot, J. C.; Boudry, V.; Braunschweig, W.; Brisson, V.; Brown, D. P.; Brückner, W.; Bruel, P.; Bruncko, D.; Bürger, J.; Büsser, F. W.; Buniatian, A.; Burke, S.; Buschhorn, G.; Calvet, D.; Campbell, A. J.; Carli, T.; Chabert, E.; Charlet, M.; Clarke, D.; Clerbaux, B.; Cocks, S.; Contreras, J. G.; Cormack, C.; Coughlan, J. A.; Cousinou, M.-C.; Cox, B. E.; Cozzika, G.; Cvach, J.; Dainton, J. B.; Dau, W. D.; Daum, K.; David, M.; Davidsson, M.; De Roeck, A.; De Wolf, E. A.; Delcourt, B.; Demirchyan, R.; Diaconu, C.; Dirkmann, M.; Dixon, P.; Dlugosz, W.; Donovan, K. T.; Dowell, J. D.; Droutskoi, A.; Ebert, J.; Eckerlin, G.; Eckstein, D.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eisenhandler, E.; Elsen, E.; Enzenberger, M.; Erdmann, M.; Farh, A. B.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Ferrarotto, F.; Fleischer, M.; Flügge, G.; Fomenko, A.; Formánek, J.; Foster, J. M.; Franke, G.; Gabathuler, E.; Gabathuler, K.; Gaede, F.; Garvey, J.; Gassner, J.; Gayler, J.; Gerhards, R.; Ghazaryan, S.; Glazov, A.; Goerlich, L.; Gogitidze, N.; Goldberg, M.; Gorelov, I.; Grab, C.; Grässler, H.; Greenshaw, T.; Griffiths, R. K.; Grindhammer, G.; Hadig, T.; Haidt, D.; Hajduk, L.; Hampel, M.; Haustein, V.; Haynes, W. J.; Heinemann, B.; Heinzelmann, G.; Henderson, R. C. W.; Hengstmann, S.; Henschel, H.; Heremans, R.; Herynek, I.; Hewitt, K.; Hiller, K. H.; Hilton, C. D.; Hladký, J.; Hoffmann, D.; Holtom, T.; Horisberger, R.; Hurling, S.; Ibbotson, M.; ??sever, Ç.; Jacquet, M.; Jaffre, M.; Jansen, D. M.; Jönsson, L.; Johnson, D. P.; Jung, H.; Kästli, H. K.; Kander, M.; Kant, D.; Kapichine, M.; Karlsson, M.; Karschnik, O.; Katzy, J.; Kaufmann, O.; Kausch, M.; Keller, N.; Kenyon, I. R.; Kermiche, S.; Keuker, C.; Kiesling, C.; Klein, M.; Kleinwort, C.; Knies, G.; Köhne, J. H.; Kolanoski, H.; Kolya, S. D.; Korbel, V.; Kostka, P.; Kotelnikov, S. K.; Krämerkämper, T.; Krasny, M. W.; Krehbiel, H.; Krücker, D.; Krüger, K.; Küpper, A.; Küster, H.; Kuhlen, M.; Kur?a, T.; Lachnit, W.; Lahmann, R.; Lamb, D.; Landon, M. P. J.; Lange, W.; Langenegger, U.; Lebedev, A.; Lehner, F.; Lemaitre, V.; Lemrani, R.; Lendermann, V.; Levonian, S.; Lindstroem, M.; Lobo, G.; Lobodzinska, E.; Lubimov, V.; Lüders, S.; Lüke, D.; Lytkin, L.; Magnussen, N.; Mahlke-Krüger, H.; Malden, N.; Malinovsky, E.; Malinovski, I.; Mara?ek, R.; Marage, P.; Marks, J.; Marshall, R.; Martyn, H.-U.; Martyniak, J.; Maxfield, S. J.; McMahon, S. J.; McMahon, T. R.; Mehta, A.; Meier, K.; Merkel, P.; Metlica, F.; Meyer, A.; Meyer, A.; Meyer, H.; Meyer, J.; Meyer, P.-O.; Mikocki, S.; Milstead, D.; Mohr, R.; Mohrdieck, S.; Mondragon, M.; Moreau, F.; Morozov, A.; Morris, J. V.; Müller, D.; Müller, K.; Murín, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, Th.; Négri, I.; Newman, P. R.; Nguyen, H. K.; Nicholls, T. C.; Niebergall, F.; Niebuhr, C.; Niedzballa, Ch.; Niggli, H.; Nix, O.; Nowak, G.; Nunnemann, T.; Oberlack, H.; Olsson, J. E.; Ozerov, D.; Palmen, P.; Panassik, V.; Pascaud, C.; Passaggio, S.; Patel, G. D.; Pawletta, H.; Perez, E.; Phillips, J. P.; Pieuchot, A.; Pitzl, D.; Pöschl, R.; Pope, G.; Povh, B.; Rabbertz, K.; Rauschenberger, J.; Reimer, P.; Reisert, B.; Reyna, D.; Rick, H.; Riess, S.; Rizvi, E.; Robmann, P.; Roosen, R.; Rosenbauer, K.; Rostovtsev, A.; Rouse, F.; Royon, C.; Rusakov, S.; Rybicki, K.; Sankey, D. P. C.; Schacht, P.; Scheins, J.; Schilling, F.-P.; Schleif, S.; Schleper, P.; Schmidt, D.; Schmidt, D.; Schoeffel, L.; Schröder, V.; Schultz-Coulon, H.-C.; Sefkow, F.; Semenov, A.; Shekelyan, V.; Sheviakov, I.; Shtarkov, L. N.; Siegmon, G.; Sirois, Y.; Sloan, T.; Smirnov, P.; Smith, M.; Solochenko, V.; Soloviev, Y.; Sonnenschein, L.; Spaskov, V.; Specka, A.; Spitzer, H.; Squinabol, F.; Stamen, R.; Steffen, P.; Steinberg, R.; Steinhart, J.; Stella, B.; Stellberger, A.; Stiewe, J.; Straumann, U.; Struczinski, W.; Sutton, J. P.; Swart, M.; Tapprogge, S.; Taševský, M.; Tchernyshov, V.; Tchetchelnitski, S.; Theissen, J.; Thompson, G.; Thompson, P. D.; Tobien, N.; Todenhagen, R.; Traynor, D.; Truöl, P.; Tsipolitis, G.; Turnau, J.; Tzamariudaki, E.; Udluft, S.; Usik, A.; Valkár, S.; Valkárová, A.; Vallée, C.; Van Esch, P.; Van Haecke, A.; Van Mechelen, P.; Vazdik, Y.; Villet, G.; Wacker, K.; Wallny, R.; Walter, T.; Waugh, B.; Weber, G.; Weber, M.; Wegener, D.; Wegner, A.; Wengler, T.; Werner, M.; West, L. R.; Wiesand, S.; Wilksen, T.; Willard, S.; Winde, M.; Winter, G.-G.; Wissing, Ch.

160

Cellular Stress Induced by Resazurin Leads to Autophagy and Cell Death Via Production of Reactive Oxygen Species and Mitochondrial Impairment  

PubMed Central

Mitochondrial bioenergetics and reactive oxygen species (ROS) often play important roles in cellular stress mechanisms. In this study we investigated how these factors are involved in the stress response triggered by resazurin (Alamar Blue) in cultured cancer cells. Resazurin is a redox reactive compound widely used as reporter agent in assays of cell biology (e.g. cell viability and metabolic activity) due to its colorimetric and fluorimetric properties. In order to investigate resazurin-induced stress mechanisms we employed cells affording different metabolic and regulatory phenotypes. In HL-60 and Jurkat leukemia cells resazurin caused mitochondrial disintegration, respiratory dysfunction, reduced proliferation, and cell death. These effects were preceded by a burst of ROS, especially in HL-60 cells which also were more sensitive and contained autophagic vesicles. Studies in Rho0 cells (devoid of mitochondrial DNA) indicated that the stress response does not depend on the rates of mitochondrial respiration. The anti-proliferative effect of resazurin was confirmed in native acute myelogenous leukemia (AML) blasts. In conclusion, the data suggest that resazurin triggers cellular ROS production and thereby initiates a stress response leading to mitochondrial dysfunction, reduced proliferation, autophagy and cell degradation. The ability of cells to tolerate this type of stress may be important in toxicity and chemoresistance. PMID:20568117

Erikstein, Bjarte Skoe; Hagland, Hanne R?land; Nikolaisen, Julie; Kulawiec, Mariola; Singh, Keshav K.; Gjertsen, Bj?rn Tore; Tronstad, Karl Johan

2010-01-01

161

Reactive desorption electrospray ionization mass spectrometry (DESI-MS) of natural products of a marine alga  

Microsoft Academic Search

Presented here is the optimization and development of a desorption electrospray ionization mass spectrometry (DESI-MS) method\\u000a for detecting natural products on tissue surfaces. Bromophycolides are algal diterpene-benzoate macrolide natural products\\u000a that have been shown to inhibit growth of the marine fungal pathogen Lindra thalassiae. As such, they have been implicated in antimicrobial chemical defense. However, the defense mechanisms are not

Leonard Nyadong; Edward G. Hohenstein; Asiri Galhena; Julia Kubanek; C. David Sherrill; Facundo M. Fernández

2009-01-01

162

The role of metals in production and scavenging of reactive oxygen species in photosystem II.  

PubMed

Metal ions play a crucial role in enzymatic reactions in all photosynthetic organisms such as cyanobacteria, algae and plants. It well known that metal ions maintain the binding of substrate in the active site of the metalloenzymes and control the redox activity of the metalloenzyme in the enzymatic reaction. A large pigment-protein complex, PSII, known to serve as a water-plastoquinone oxidoreductase, contains three metal centers comprising non-heme iron, heme iron of Cyt b559 and the water-splitting manganese complex. Metal ions bound to PSII proteins maintain the electron transport from water to plastoquinone and regulate the pro-oxidant and antioxidant activity in PSII. In this review, attention is focused on the role of PSII metal centers in (i) the formation of superoxide anion and hydroxyl radicals by sequential one-electron reduction of molecular oxygen and the formation of hydrogen peroxide by incomplete two-electron oxidation of water; and (ii) the elimination of superoxide anion radical by one-electron oxidation and reduction (superoxide dismutase activity) and of hydrogen peroxide by two-electron oxidation and reduction (catalase activity). The balance between the formation and elimination of reactive oxygen species by PSII metal centers is discussed as an important aspect in the prevention of photo-oxidative damage of PSII proteins and lipids. PMID:24771559

Pospíšil, Pavel

2014-07-01

163

Mitochondrial metabolic suppression and reactive oxygen species production in liver and skeletal muscle of hibernating thirteen-lined ground squirrels.  

PubMed

During hibernation, animals cycle between periods of torpor, during which body temperature (T(b)) and metabolic rate (MR) are suppressed for days, and interbout euthermia (IBE), during which T(b) and MR return to resting levels for several hours. In this study, we measured respiration rates, membrane potentials, and reactive oxygen species (ROS) production of liver and skeletal muscle mitochondria isolated from ground squirrels (Ictidomys tridecemlineatus) during torpor and IBE to determine how mitochondrial metabolism is suppressed during torpor and how this suppression affects oxidative stress. In liver and skeletal muscle, state 3 respiration measured at 37°C with succinate was 70% and 30% lower, respectively, during torpor. In liver, this suppression was achieved largely via inhibition of substrate oxidation, likely at succinate dehydrogenase. In both tissues, respiration by torpid mitochondria further declined up to 88% when mitochondria were cooled to 10°C, close to torpid T(b). In liver, this passive thermal effect on respiration rate reflected reduced activity of all components of oxidative phosphorylation (substrate oxidation, phosphorylation, and proton leak). With glutamate + malate and succinate, mitochondrial free radical leak (FRL; proportion of electrons leading to ROS production) was higher in torpor than IBE, but only in liver. With succinate, higher FRL likely resulted from increased reduction state of complex III during torpor. With glutamate + malate, higher FRL resulted from active suppression of complex I ROS production during IBE, which may limit ROS production during arousal. In both tissues, ROS production and FRL declined with temperature, suggesting ROS production is also reduced during torpor by passive thermal effects. PMID:21993528

Brown, Jason C L; Chung, Dillon J; Belgrave, Kathleen R; Staples, James F

2012-01-01

164

A Quantitative Method to Monitor Reactive Oxygen Species Production by Electron Paramagnetic Resonance in Physiological and Pathological Conditions  

PubMed Central

The growing interest in the role of Reactive Oxygen Species (ROS) and in the assessment of oxidative stress in health and disease clashes with the lack of consensus on reliable quantitative noninvasive methods applicable. The study aimed at demonstrating that a recently developed Electron Paramagnetic Resonance microinvasive method provides direct evidence of the “instantaneous” presence of ROS returning absolute concentration levels that correlate with “a posteriori” assays of ROS-induced damage by means of biomarkers. The reliability of the choice to measure ROS production rate in human capillary blood rather than in plasma was tested (step I). A significant (P < 0.01) linear relationship between EPR data collected on capillary blood versus venous blood (R2 = 0.95), plasma (R2 = 0.82), and erythrocytes (R2 = 0.73) was found. Then (step II) ROS production changes of various subjects' categories, young versus old and healthy versus pathological at rest condition, were found significantly different (range 0.0001–0.05 P level). The comparison of the results with antioxidant capacity and oxidative damage biomarkers concentrations showed that all changes indicating increased oxidative stress are directly related to ROS production increase. Therefore, the adopted method may be an automated technique for a lot of routine in clinical trials. PMID:25374651

Mrakic-Sposta, Simona; Gussoni, Maristella; Montorsi, Michela; Porcelli, Simone; Vezzoli, Alessandra

2014-01-01

165

Effect of 6 months' training on the reactive oxygen species production capacity of neutrophils and serum opsonic activity in judoists.  

PubMed

The effects of long-term training on the production of reactive oxygen species (ROS) from neutrophils and serum opsonic activity (SOA) remain to date unknown. The aim of this study was to evaluate the effect of 6 months training on ROS production and SOA in judoists. Fifty-six judoists were enrolled this study. White blood cell counts, serum creatine kinase (CK), asparate aminotransferase (ASAT), alanine aminotransferase (ALAT), lactate dehydrogenase (LDH) and ROS production from neutrophils, and serum opsonic activity (SOA) using the lucigenin and luminol probes, were measured before and after daily judo exercise (2 h) in March and September. The subjects started their training from March after no exercise for three months, and continued it for 6 months (until September). In March, myogenic enzymes such as CK, ASAT, LDH and neutrophil counts increased and immunoglobulins, complements and SOA decreased after daily judo exercise. Such significant changes were not seen in September. On the other hand, ROS significantly increased after daily judo exercise in both March and September, with no significant difference in the rates of change. In conclusion, 6 month training minimized the changes in SOA as well as muscle enzymes, neutrophil counts, serum immunoglobulins and complements. This could be categorized as a long-term training effect. However, no such change was seen in ROS. PMID:15586397

Miura, Masashi; Umeda, Takashi; Nakaji, Shigeyuki; Liu, Qiang; Tanabe, Masaru; Kojima, Arata; Yamamoto, Yousuke; Sugawara, Kazuo

2005-01-01

166

Aging and Luteinizing Hormone Effects on Reactive Oxygen Species Production and DNA Damage in Rat Leydig Cells1  

PubMed Central

ABSTRACT We observed previously that after long-term suppression of luteinizing hormone (LH) and thus of Leydig cell steroidogenesis, restimulation of the Leydig cells by LH resulted in significantly higher testosterone production than by age-matched cells from control rats. These studies suggest that stimulation over time may elicit harmful effects on the steroidogenic machinery, perhaps through alteration of the intracellular oxidant-to-antioxidant balance. Herein we compared the effects of LH stimulation on stress response genes, formation of intracellular reactive oxygen species (ROS), and ROS-induced damage to ROS-susceptible macromolecules (DNA) in young and in aged cells. Microarray analysis indicated that LH stimulation resulted in significant increases in expression of genes associated with stress response and antiapoptotic pathways. Short-term LH treatment of primary Leydig cells isolated from young rats resulted in transiently increased ROS levels compared to controls. Aged Leydig cells also showed increased ROS soon after LH stimulation. However, in contrast to the young cells, ROS production peaked later and the time to recovery was increased. In both young and aged cells, treatment with LH resulted in increased levels of DNA damage but significantly more so in the aged cells. DNA damage levels in response to LH and the levels of intracellular ROS were highly correlated. Taken together, these results indicate that LH stimulation causes increased ROS production by young and aged Leydig cells and that while DNA damage occurs in cells of both ages, there is greater damage in the aged cells. PMID:23486914

Beattie, Matthew C.; Chen, Haolin; Fan, Jinjiang; Papadopoulos, Vassilios; Miller, Paul; Zirkin, Barry R.

2013-01-01

167

Enhanced production of validamycin A by H2O2-induced reactive oxygen species in fermentation of Streptomyces hygroscopicus 5008.  

PubMed

A novel fermentation strategy to enhance antibiotics production was demonstrated by inducing reactive oxygen species (ROS), and validamycin A (VAL-A) production by Streptomyces hygroscopicus 5008 in agro-industrial residues containing medium was taken as an example. By optimizing H2O2 amount and addition time, the intracellular ROS level was increased, and VAL-A production titer was enhanced by 40% on day 4 when 25 ?M H2O2 was added at 8th h of fermentation. Addition of diphenyleneiodonium chloride (ROS inhibitor) reduced the H2O2 induction effect. The transcription level of eight VAL-A structure genes was enhanced by ROS, and activities of glucose-6-phosphate dehydrogenase and ValG enzyme were increased while glyceraldehyde 3-phosphate dehydrogenase activity was inhibited. This work demonstrated that ROS induction was a useful strategy for VAL-A fermentation, and the information on gene transcription and enzyme activities may be helpful to further understanding the mechanism of ROS effect on the antibiotic biosynthesis. PMID:20952185

Wei, Zhen-Hua; Bai, Linquan; Deng, Zixin; Zhong, Jian-Jiang

2011-01-01

168

Optimization of supercritical methanol reactive extraction by response surface methodology and product characterization from Jatropha curcas L. seeds.  

PubMed

In this study, optimization of supercritical reactive extraction directly from Jatropha seeds in a high pressure batch reactor using Response Surface Methodology (RSM) coupled with Central Composite Rotatable Design (CCRD) was performed. Four primary variables (methanol to solid ratio (SSR), reaction temperature, time and CO2 initial pressure) were investigated under the proposed constraints. It was found that all variables had significant effects towards fatty acid methyl esters (FAME) yield. Moreover, three interaction effects between the variables also played a major role in influencing the final FAME yield. Optimum FAME yield at 92.0 wt.% was achieved under the following conditions: 5.9 SSR, 300°C, 12.3 min and 20 bar CO2. Final FAME product was discovered to fulfil existing international standard. Preliminary characterization analysis proved that the solid residue can be burnt as solid fuel in the form of biochar while the liquid product can be separated as specialty chemicals or burned as bio-oil for energy production. PMID:23735793

Lim, Steven; Lee, Keat Teong

2013-08-01

169

A role for human mitochondrial complex II in the production of reactive oxygen species in human skin  

PubMed Central

The mitochondrial respiratory chain is a major generator of cellular oxidative stress, thought to be an underlying cause of the carcinogenic and ageing process in many tissues including skin. Previous studies of the relative contributions of the respiratory chain (RC) complexes I, II and III towards production of reactive oxygen species (ROS) have focussed on rat tissues and certainly not on human skin which is surprising as this tissue is regularly exposed to UVA in sunlight, a potent generator of cellular oxidative stress. In a novel approach we have used an array of established specific metabolic inhibitors and DHR123 fluorescence to study the relative roles of the mitochondrial RC complexes in cellular ROS production in 2 types of human skin cells. These include additional enhancement of ROS production by exposure to physiological levels of UVA. The effects within epidermal and dermal derived skin cells are compared to other tissue cell types as well as those harbouring a compromised mitochondrial status (Rho-zero A549). The results show that the complex II inhibitor, TTFA, was the only RC inhibitor to significantly increase UVA-induced ROS production in both skin cell types (P<0.05) suggesting that the role of human skin complex II in terms of influencing ROS production is more important than previously thought particularly in comparison to liver cells. Interestingly, two-fold greater maximal activity of complex II enzyme was observed in both skin cell types compared to liver (P<0.001). The activities of RC enzymes appear to decrease with increasing age and telomere length is correlated with ageing. Our study showed that the level of maximal complex II activity was higher in the MRC5/hTERT (human lung fibroblasts transfected with telomerase) cells than the corresponding wild type cells (P=0.0012) which can be considered (in terms of telomerase activity) as models of younger and older cells respectively.

Anderson, Alasdair; Bowman, Amy; Boulton, Sarah Jayne; Manning, Philip; Birch-Machin, Mark A.

2014-01-01

170

Land, irrigation water, greenhouse gas, and reactive nitrogen burdens of meat, eggs, and dairy production in the United States  

PubMed Central

Livestock production impacts air and water quality, ocean health, and greenhouse gas (GHG) emissions on regional to global scales and it is the largest use of land globally. Quantifying the environmental impacts of the various livestock categories, mostly arising from feed production, is thus a grand challenge of sustainability science. Here, we quantify land, irrigation water, and reactive nitrogen (Nr) impacts due to feed production, and recast published full life cycle GHG emission estimates, for each of the major animal-based categories in the US diet. Our calculations reveal that the environmental costs per consumed calorie of dairy, poultry, pork, and eggs are mutually comparable (to within a factor of 2), but strikingly lower than the impacts of beef. Beef production requires 28, 11, 5, and 6 times more land, irrigation water, GHG, and Nr, respectively, than the average of the other livestock categories. Preliminary analysis of three staple plant foods shows two- to sixfold lower land, GHG, and Nr requirements than those of the nonbeef animal-derived calories, whereas irrigation requirements are comparable. Our analysis is based on the best data currently available, but follow-up studies are necessary to improve parameter estimates and fill remaining knowledge gaps. Data imperfections notwithstanding, the key conclusion—that beef production demands about 1 order of magnitude more resources than alternative livestock categories—is robust under existing uncertainties. The study thus elucidates the multiple environmental benefits of potential, easy-to-implement dietary changes, and highlights the uniquely high resource demands of beef. PMID:25049416

Eshel, Gidon; Shepon, Alon; Makov, Tamar; Milo, Ron

2014-01-01

171

Robust, high reactivity and enhanced capacity carbon dioxide removal agents for hydrogen production applications  

Microsoft Academic Search

The first step of forming hydrogen from carbonaceous solid fuels (coal, biomass) is gasification, followed by water gas shift reaction and separation of the carbon dioxide and hydrogen. Several processes, such as the HyP-RING process, reaction swing methodology by SIU (Southern Illinois University), chemical looping processes, etc., have been developed for hydrogen production involving the use of CaO as the

D. Dasgupta; K. Mondal; T. Wiltowski

2008-01-01

172

Individual differences in trait motivational reactivity influence children and adolescents' responses to pictures of taboo products.  

PubMed

This study examined how children and adolescents respond to pictures of products whose use, for them, is socially or legally restricted (e.g., beer, liquor, cigarettes). It was theorized and found that these pictures, referred to as taboo, elicit an automatic motivational activation whose direction and intensity are influenced by age and individual differences in defensive system activation. Results show that 11-12-year-old children demonstrate primarily aversive responses to taboo products, 13-15-year-old children have less aversive responses, and 16-17-year-old children have mixed appetitive and aversive motivational responses. Further, those with high defensive system activation show larger aversive and smaller appetitive responses across the age groups. These results suggest that placing pictures of these products in prevention messages may work for the prevention goal of reduced experimentation and risk in younger children but against the prevention goal for the older children who may be more likely to be exposed to opportunities for experimentation and use. PMID:24730592

Lang, Annie; Lee, Sungkyoung

2014-09-01

173

Measurement of dijet production in neutral current deep inelastic scattering at high Q 2 and determination of ? s  

Microsoft Academic Search

Dijet production has been studied in neutral current deep inelastic e+p scattering for 470

S. Bhadra; C. D. Catterall; W. R. Frisken; R. Hall-Wilton; M. Khakzad; S. Magill; B. Musgrave; A. Pellegrino; J. Repond; R. Stanek; R. Yoshida; M. C. K. Mattingly; P. Antonioli; G. Bari; M. Basile; L. Bellagamba; D. Boscherini; A. Bruni; G. Bruni; G. Cara Romeo; L. Cifarelli; F. Cindolo; A. Contin; M. Corradi; S. De Pasquale; P. Giusti; G. Iacobucci; G. Levi; A. Margotti; T. Massam; R. Nania; F. Palmonari; A. Pesci; G. Sartorelli; A. Zichichi; G. Aghuzumtsyan; C. Amelung; I. Brock; K. Coböken; S. Goers; H. Hartmann; K. Heinloth; E. Hilger; P. Irrgang; H.-P. Jakob; A. Kappes; U. F. Katz; R. Kerger; O. Kind; E. Paul; J. Rautenberg; H. Schnurbusch; A. Stifutkin; J. Tandler; K. C. Voss; A. Weber; H. Wieber; D. S. Bailey; O. Barret; N. H. Brook; J. E. Cole; B. Foster; G. P. Heath; H. F. Heath; S. Robins; E. Rodrigues; J. Scott; R. J. Tapper; M. Capua; A. Mastroberardino; M. Schioppa; G. Susinno; H. Y. Jeoung; J. Y. Kim; J. H. Lee; I. T. Lim; K. J. Ma; M. Y. Pac; A. Caldwell; W. Liu; X. Liu; B. Mellado; S. Paganis; S. Sampson; W. B. Schmidke; F. Sciulli; J. Chwastowski; A. Eskreys; J. Figiel; K. Klimek; K. Olkiewicz; M. Przybycien; P. Stopa; L. Zawiejski; B. Bednarek; K. Jelen; D. Kisielewska; A. M. Kowal; T. Kowalski; E. Rulikowska-Zarebska; L. Suszycki; D. Szuba; A. Kotanski; L. A. T. Bauerdick; U. Behrens; J. K. Bienlein; K. Borras; V. Chiochia; J. Crittenden; D. Dannheim; K. Desler; G. Drews; A. Fox-Murphy; U. Fricke; F. Goebel; P. Göttlicher; R. Graciani; T. Haas; W. Hain; G. F. Hartner; K. Hebbel; S. Hillert; W. Koch; U. Kötz; H. Kowalski; H. Labes; B. Löhr; R. Mankel; J. Martens; M. Martínez; M. Milite; M. Moritz; D. Notz; M. C. Petrucci; A. Polini; M. Rohde; A. A. Savin; U. Schneekloth; F. Selonke; S. Stonjek; G. Wolf; U. Wollmer; C. Youngman; W. Zeuner; C. Coldewey; A. Lopez-Duran Viani; A. Meyer; S. Schlenstedt; P. B. Straub; G. Barbagli; E. Gallo; A. Parenti; P. G. Pelfer; A. Bamberger; A. Benen; N. Coppola; S. Eisenhardt; P. Markun; H. Raach; S. Wölfle; M. Bell; P. J. Bussey; A. T. Doyle; C. Glasman; S. W. Lee; A. Lupi; N. Macdonald; G. J. McCance; D. H. Saxon; L. E. Sinclair; I. O. Skillicorn; R. Waugh; B. Bodmann; N. Gendner; U. Holm; H. Salehi; K. Wick; A. Yildirim; A. Ziegler; T. Carli; A. Garfagnini; A. Geiser; I. Gialas; D. Kçira; E. Lohrmann; R. Gonçalo; K. R. Long; D. B. Miller; A. D. Tapper; R. Walker; P. Cloth; D. Filges; T. Ishii; M. Kuze; K. Nagano; K. Tokushuku; S. Yamada; Y. Yamazaki; A. N. Barakbaev; E. G. Boos; N. S. Pokrovskiy; B. O. Zhautykov; S. H. Ahn; S. B. Lee; S. K. Park; H. Lim; D. Son; F. Barreiro; G. García; O. González; L. Labarga; J. del Peso; I. Redondo; J. Terrón; M. Vázquez; M. Barbi; F. Corriveau; S. Padhi; D. G. Stairs; M. Wing; T. Tsurugai; A. Antonov; V. Bashkirov; P. Danilov; B. A. Dolgoshein; D. Gladkov; V. Sosnovtsev; S. Suchkov; R. K. Dementiev; P. F. Ermolov; Y. A. Golubkov; I. I. Katkov; L. A. Khein; N. A. Korotkova; I. A. Korzhavina; V. A. Kuzmin; O. Y. Lukina; A. S. Proskuryakov; L. M. Shcheglova; A. N. Solomin; N. N. Vlasov; S. A. Zotkin; C. Bokel; M. Botje; J. Engelen; S. Grijpink; E. Koffeman; P. Kooijman; S. Schagen; A. van Sighem; E. Tassi; H. Tiecke; N. Tuning; J. J. Velthuis; J. Vossebeld; L. Wiggers; E. de Wolf; N. Brümmer; B. Bylsma; L. S. Durkin; J. Gilmore; C. M. Ginsburg; C. L. Kim; T. Y. Ling; S. Boogert; A. M. Cooper-Sarkar; R. C. E. Devenish; J. Große-Knetter; T. Matsushita; O. Ruske; M. R. Sutton; R. Walczak; A. Bertolin; R. Brugnera; R. Carlin; F. Dal Corso; S. Dusini; S. Limentani; A. Longhin; M. Posocco; L. Stanco; M. Turcato; L. Adamczyk; L. Iannotti; B. Y. Oh; J. R. Okrasinski; P. R. B. Saull; W. S. Toothacker; J. J. Whitmore; Y. Iga; G. D'Agostini; G. Marini; A. Nigro; C. Cormack; J. C. Hart; N. A. McCubbin; T. P. Shah; D. Epperson; C. Heusch; H. F.-W. Sadrozinski; A. Seiden; R. Wichmann; D. C. Williams; I. H. Park; N. Pavel; H. Abramowicz; S. Dagan; A. Gabareen; S. Kananov; A. Kreisel; A. Levy; T. Abe; T. Fusayasu; T. Kohno; K. Umemori; T. Yamashita; R. Hamatsu; T. Hirose; M. Inuzuka; S. Kitamura; K. Matsuzawa; T. Nishimura; M. Arneodo; N. Cartiglia; R. Cirio; M. Costa; M. I. Ferrero; S. Maselli; V. Monaco; C. Peroni; M. Ruspa; R. Sacchi; A. Solano; A. Staiano; D. C. Bailey; C.-P. Fagerstroem; R. Galea; T. Koop; G. M. Levman; J. F. Martin; A. Mirea; A. Sabetfakhri; J. M. Butterworth; C. Gwenlan; M. E. Hayes; E. A. Heaphy; T. W. Jones; B. J. West; J. Ciborowski; R. Ciesielski; G. Grzelak; R. J. Nowak; J. M. Pawlak; R. Pawlak; B. Smalska; T. Tymieniecka; A. K. Wróblewski; J. A. Zakrzewski; A. F. arnecki; M. Adamus; T. Gadaj; O. Deppe; Y. Eisenberg; L. K. Gladilin; D. Hochman; U. Karshon; W. F. Badgett; D. Chapin; R. Cross; C. Foudas; S. Mattingly; D. D. Reeder; W. H. Smith; A. Vaiciulis; T. Wildschek; M. Wodarczyk; A. Deshpande; S. Dhawan; V. W. Hughes; S. Menary

2001-01-01

174

P11 Resonances with Dubna-Mainz-Taipei dynamical model for ?N scattering and pion electromagnetic production  

NASA Astrophysics Data System (ADS)

We present the results on P11 resonances obtained with Dubna-Mainz-Taipei (DMT) dynamical model for pion-nucleon scattering and pion electromagnetic production. The extracted values agree well, in general, with PDG values. One pole is found corresponding to the Roper resonance and two more resonances are definitely needed in DMT model. We further find indication for a narrow P11 resonance at around 1700 MeV with a width ~ 50 MeV in both ?N and ?? reactions.

Yang, Shin Nan; Kamalov, S. S.; Tiator, L.

2012-04-01

175

Rapid and reactive nitric oxide production by astrocytes in mouse neocortical slices  

Microsoft Academic Search

ABSTRACT Nitric oxide (NO), a cellular signaling molecule, is produced in the brain,by both neurons,and,astrocytes. While neurons are capable,of rapid release of small,amounts,of NO serving as neurotransmitter, astrocytic NO production has been demonstrated,mainly,as a slow,reaction,to various,stress stimuli. Little is known,about,the,role,of astrocyte-pro- duced NO. Using the NO indicator 4,5-diaminofluorescein-2 diacetate (DAF-2DA) and acute slices from mouse brain, we distinguished,neurons,from,astrocytes,based,on their differ-

Yossi Buskila; Shai Farkash; Michal Hershfinkel; Yael Amitai

2005-01-01

176

A Production System Model of Capturing Reactive Moving Targets. M.S. Thesis  

NASA Technical Reports Server (NTRS)

Subjects manipulated a control stick to position a cursor over a moving target that reacted with a computer-generated escape strategy. The cursor movements were described at two levels of abstraction. At the upper level, a production system described transitions among four modes of activity; rapid acquisition, close following, a predictive mode, and herding. Within each mode, differential equations described trajectory-generating mechanisms. A simulation of this two-level model captures the targets in a manner resembling the episodic time histories of human subjects.

Jagacinski, R. J.; Plamondon, B. D.; Miller, R. A.

1984-01-01

177

The role of oxidized cytochrome c in regulating mitochondrial reactive oxygen species production and its perturbation in ischaemia  

PubMed Central

Oxidized cytochrome c is a powerful superoxide scavenger within the mitochondrial IMS (intermembrane space), but the importance of this role in situ has not been well explored. In the present study, we investigated this with particular emphasis on whether loss of cytochrome c from mitochondria during heart ischaemia may mediate the increased production of ROS (reactive oxygen species) during subsequent reperfusion that induces mPTP (mitochondrial permeability transition pore) opening. Mitochondrial cytochrome c depletion was induced in vitro with digitonin or by 30 min ischaemia of the perfused rat heart. Control and cytochrome c-deficient mitochondria were incubated with mixed respiratory substrates and an ADP-regenerating system (State 3.5) to mimic physiological conditions. This contrasts with most published studies performed with a single substrate and without significant ATP turnover. Cytochrome c-deficient mitochondria produced more H2O2 than control mitochondria, and exogenous cytochrome c addition reversed this increase. In the presence of increasing [KCN] rates of H2O2 production by both pre-ischaemic and end-ischaemic mitochondria correlated with the oxidized cytochrome c content, but not with rates of respiration or NAD(P)H autofluorescence. Cytochrome c loss during ischaemia was not mediated by mPTP opening (cyclosporine-A insensitive), neither was it associated with changes in mitochondrial Bax, Bad, Bak or Bid. However, bound HK2 (hexokinase 2) and Bcl-xL were decreased in end-ischaemic mitochondria. We conclude that cytochrome c loss during ischaemia, caused by outer membrane permeabilization, is a major determinant of H2O2 production by mitochondria under pathophysiological conditions. We further suggest that in hypoxia, production of H2O2 to activate signalling pathways may be also mediated by decreased oxidized cytochrome c and less superoxide scavenging. PMID:21410437

Pasdois, Philippe; Parker, Joanne E.; Griffiths, Elinor J.; Halestrap, Andrew P.

2011-01-01

178

Rapid and reactive nitric oxide production by astrocytes in mouse neocortical slices.  

PubMed

Nitric oxide (NO), a cellular signaling molecule, is produced in the brain by both neurons and astrocytes. While neurons are capable of rapid release of small amounts of NO serving as neurotransmitter, astrocytic NO production has been demonstrated mainly as a slow reaction to various stress stimuli. Little is known about the role of astrocyte-produced NO. Using the NO indicator 4,5-diaminofluorescein-2 diacetate (DAF-2DA) and acute slices from mouse brain, we distinguished neurons from astrocytes based on their different fluorescence kinetics and pattern, cellular morphology, electrophysiology, and responses to selective nitric oxide synthase (NOS) inhibitors. Typically, astrocytic fluorescence followed neuronal fluorescence with a delay of 1-2 min and was dependent on the inducible NOS isoform (iNOS) activity. Western blot analysis established the presence of functional iNOS in the neocortex. An assay for cell death revealed that most DAF-2DA-positive neurons, but not astrocytes, were damaged. Whole cell recordings from astrocytes confirmed that these cells maintained their membrane potential and passive properties during illumination and afterward. Induction of excitotoxicity by brief application of glutamate triggered an immediate and intense astrocytic response, while high-frequency electrical stimulation failed to do so. The present study demonstrates, for the first time, rapid and massive iNOS-dependent NO production by astrocytes in situ, which appears to be triggered by acute neuronal death. These data may bear important implications for our theoretical understanding and practical management of acute brain insults. PMID:15968628

Buskila, Yossi; Farkash, Shai; Hershfinkel, Michal; Amitai, Yael

2005-11-15

179

Effect of potential-dependent potassium uptake on production of reactive oxygen species in rat brain mitochondria.  

PubMed

The effect of potential-dependent potassium uptake on reactive oxygen species (ROS) generation in mitochondria of rat brain was studied. It was found that the effect of K+ uptake on ROS production in the brain mitochondria under steady-state conditions (state 4) was determined by potassium-dependent changes in the membrane potential of the mitochondria (??m). At K+ concentrations within the range of 0-120 mM, an increase in the initial rate of K(+)-uptake into the matrix resulted in a decrease in the steady-state rate of ROS generation due to the K(+)-induced depolarization of the mitochondrial membrane. The selective blockage of the ATP-dependent potassium channel (K(ATP)(+)-channel) by glibenclamide and 5-hydroxydecanoate resulted in an increase in ROS production due to the membrane repolarization caused by partial inhibition of the potential-dependent K+ uptake. The ATP-dependent transport of K+ was shown to be ~40% of the potential-dependent K+ uptake in the brain mitochondria. Based on the findings of the experiments, the potential-dependent transport of K+ was concluded to be a physiologically important regulator of ROS generation in the brain mitochondria and that the functional activity of the native K(ATP)(+)-channel in these organelles under physiological conditions can be an effective tool for preventing ROS overproduction in brain neurons. PMID:24512663

Akopova, O V; Kolchinskaya, L I; Nosar, V I; Bouryi, V A; Mankovska, I N; Sagach, V F

2014-01-01

180

Induction of apoptosis in human multiple myeloma cell lines by ebselen via enhancing the endogenous reactive oxygen species production.  

PubMed

Ebselen a selenoorganic compound showing glutathione peroxidase like activity is an anti-inflammatory and antioxidative agent. Its cytoprotective activity has been investigated in recent years. However, experimental evidence also shows that ebselen causes cell death in several cancer cell types whose mechanism has not yet been elucidated. In this study, we examined the effect of ebselen on multiple myeloma (MM) cell lines in vitro. The results showed that ebselen significantly enhanced the production of reactive oxygen species (ROS) accompanied by cell viability decrease and apoptosis rate increase. Further studies revealed that ebselen can induce Bax redistribution from the cytosol to mitochondria leading to mitochondrial membrane potential ??m changes and cytochrome C release from the mitochondria to cytosol. Furtherly, we found that exogenous addition of N-acetyl cysteine (NAC) completely diminished the cell damage induced by ebselen. This result suggests that relatively high concentration of ebselen can induce MM cells apoptosis in culture by enhancing the production of endogenous ROS and triggering mitochondria mediated apoptotic pathway. PMID:24587987

Zhang, Liang; Zhou, Liwei; Du, Jia; Li, Mengxia; Qian, Chengyuan; Cheng, Yi; Peng, Yang; Xie, Jiayin; Wang, Dong

2014-01-01

181

Perfluorooctane sulfonate (PFOS) induces reactive oxygen species (ROS) production in human microvascular endothelial cells: role in endothelial permeability.  

PubMed

Perfluorooctane sulfonate (PFOS) is a member of the perfluoroalkyl acids (PFAA) containing an eight-carbon backbone. PFOS is a man-made chemical with carbon-fluorine bonds that are among the strongest in organic chemistry, and PFOS is widely used in industry. Human occupational and environmental exposure to PFOS occurs globally. PFOS is non-biodegradable and is persistent in the human body and environment. In this study, data demonstrated that exposure of human microvascular endothelial cells (HMVEC) to PFOS induced the production of reactive oxygen species (ROS) at both high and low concentrations. Morphologically, it was found that exposure to PFOS induced actin filament remodeling and endothelial permeability changes in HMVEC. Furthermore, data demonstrated that the production of ROS plays a regulatory role in PFOS-induced actin filament remodeling and the increase in endothelial permeability. Our results indicate that the generation of ROS may play a role in PFOS-induced aberrations of the endothelial permeability barrier. The results generated from this study may provide a new insight into the potential adverse effects of PFOS exposure on humans at the cellular level. PMID:20391123

Qian, Yong; Ducatman, Alan; Ward, Rebecca; Leonard, Steve; Bukowski, Valerie; Lan Guo, Nancy; Shi, Xianglin; Vallyathan, Val; Castranova, Vincent

2010-01-01

182

Induction of Apoptosis in Human Multiple Myeloma Cell Lines by Ebselen via Enhancing the Endogenous Reactive Oxygen Species Production  

PubMed Central

Ebselen a selenoorganic compound showing glutathione peroxidase like activity is an anti-inflammatory and antioxidative agent. Its cytoprotective activity has been investigated in recent years. However, experimental evidence also shows that ebselen causes cell death in several cancer cell types whose mechanism has not yet been elucidated. In this study, we examined the effect of ebselen on multiple myeloma (MM) cell lines in vitro. The results showed that ebselen significantly enhanced the production of reactive oxygen species (ROS) accompanied by cell viability decrease and apoptosis rate increase. Further studies revealed that ebselen can induce Bax redistribution from the cytosol to mitochondria leading to mitochondrial membrane potential ??m changes and cytochrome C release from the mitochondria to cytosol. Furtherly, we found that exogenous addition of N-acetyl cysteine (NAC) completely diminished the cell damage induced by ebselen. This result suggests that relatively high concentration of ebselen can induce MM cells apoptosis in culture by enhancing the production of endogenous ROS and triggering mitochondria mediated apoptotic pathway. PMID:24587987

Du, Jia; Li, Mengxia; Qian, Chengyuan; Cheng, Yi; Peng, Yang; Xie, Jiayin; Wang, Dong

2014-01-01

183

Oxygen therapy does not increase production and damage induced by reactive oxygen species in focal cerebral ischemia.  

PubMed

Oxygen therapy with hyperbaric oxygen (HBO) or normobaric hyperoxia (NBO) improves outcome in experimental cerebral ischemia. However, an increased formation of reactive oxygen species (ROS) may be an undesirable side effect of oxygen therapy. We investigated the effect of both oxygen therapies on ROS production and adverse effects in murine focal ischemia. 25 min after 90 min filament-induced middle cerebral artery occlusion (MCAO), mice breathed either air, 100% O2 (NBO), or 100% O2 at 3 ata (HBO) for 60 min. ROS were depicted on tissue sections after preischemic injection of hydroethidine, a marker of in vivo superoxide production. Moreover, infarct sizes were quantified in experiments using peroxybutinitrite (PBN) in mice treated with HBO. Effects of oxygen therapy were also tested in superoxide 2 knock-out mice. Both NBO and HBO significantly reduced superoxide radicals compared to air. Application of PBN had no additional protective effect when combined with HBO. Infarct volumes did not differ among SOD2 knock-out mice receiving air (34.0 ± 19.6mm(3)), NBO (35.4 ± 14.3mm(3)) or HBO (33.4 ± 12.2mm(3)). In conclusion, brief episodes of oxygen therapy do not appear to promote damage inflicted by ROS in experimental stroke. PMID:24909618

Sun, Li; Wolferts, Guido; Veltkamp, Roland

2014-08-01

184

Production of laccase from Pleurotus florida using agro-wastes and efficient decolorization of Reactive blue 198.  

PubMed

Pleurotus florida NCIM 1243 produced laccase as the dominant lignolytic enzyme during the dye decolorization. Banana peel was the best substrate for extracellular laccase production under solid state fermentation when compared to mandarin peel and cantaloupe peel. The maximum activity of laccase (5.4 U/g) was detected on the 10 day. The ratio of banana peel: mandarin peel: cantaloupe peel (5:2:3) showed increased production of laccase (6.8 U/g). P. florida produced two extracellular laccase isoenzymes (L1 and L2). The half life of laccase at 60 degrees C was 2 h and at 4 h it retained 25% residual activity. P. florida laccase showed high thermostability and an interesting difference was noticed in the behavior of laccase isoenzymes at different temperature. The L1 isoenzyme of laccase showed remarked thermostability at 60 degrees C in the native PAGE when compared to L2 isoenzyme. The optimum pH, temperature and enzyme concentration for maximum decolorization was found to be 4.5, 60 degrees C and 1.2 U/ml, respectively. Partially purified laccase enzyme showed excellent decolorization activity to Reactive blue 198. The maximum decolorization (96%) was observed at lower dye concentrations (50-100 ppm) which decreased markedly when the dye concentration was increased beyond 150 ppm. The thermostable laccase of P. florida could be effectively used to decolorize the synthetic dyes in the textile effluent and other biotechnological applications. PMID:20586068

Sathishkumar, P; Murugesan, K; Palvannan, T

2010-08-01

185

Elastic scattering and heavy residue production in the collisions 6,7Li+64 Zn around the Coulomb barrier  

NASA Astrophysics Data System (ADS)

Elastic scattering angular distributions and heavy residue production cross sections have been measured at different energies around the Coulomb barrier for the systems 6,7Li+64Zn. Optical model fits of the elastic angular distributions were performed using a renormalized double folding potential and absence of usual threshold anomaly in the optical potential was found. Excitation functions for heavy residue production have been measured using an activation technique. Comparison of the data with the results of different calculations show that complete fusion is the dominant reaction mechanism above the barrier, whereas the heavy residue yield below the barrier is mainly due to incomplete fusion and transfer.

Figuera, P.; Di Pietro, A.; Strano, E.; Fisichella, M.; Lattuada, M.; Milin, M.; Musumarra, A.; Ostashko, V.; Pellegriti, M. G.; Randisi, G.; Scuderi, V.; Torresi, D.; Zadroa, M.

2013-12-01

186

A Structural Determinant of Chemical Reactivity and Potential Health Effects of Quinones from Natural Products  

PubMed Central

Although many phenols and catechols found as polyphenol natural products are antioxidants and have putative disease-preventive properties, others have deleterious health effects. One possible route to toxicity is the bioactivation of the phenolic function to quinones that are electrophilic, redox-agents capable of modifying DNA and proteins. The structure-property relationships of biologically important quinones and their precursors may help understand the balance between their health benefits and risks. We describe a mass-spectrometry-based study of four quinones produced by oxidizing flavanones and flavones. Those with a C2-C3 double bond on ring C of the flavonoid stabilize by delocalization an incipient positive charge from protonation and render the protonated quinone particularly susceptible to nucleophilic attack. We hypothesize that the absence of this double bond is one specific structural determinant that is responsible for the ability of quinones to modify biological macromolecules. Those quinones containing a C2-C3 single bond have relative higher aqueous stability and longer half-lives than those with a double bond at the same position; the latter have short half-lives at or below ~ 1 s. Quinones with a C2-C3 double bond show little ability to depurinate DNA because they are rapidly hydrated to unreactive species. Molecular-orbital calculations support that quinone hydration by a highly structure-dependent mechanism accounts for their chemical properties. The evidence taken together support a hypothesis that those flavonoids and related natural products that undergo oxidation to quinones and are then rapidly hydrated are unlikely to damage important biological macromolecules. PMID:21721570

Tu, Tingting; Giblin, Daryl; Gross, Michael L.

2011-01-01

187

Effects of oxysterols on cell viability, inflammatory cytokines, VEGF and reactive oxygen species production on human retinal cells: cytoprotective effects and prevention of VEGF  

E-print Network

production on human retinal cells: cytoprotective effects and prevention of VEGF secretion by resveratrol B cytokines; oxysterols; phospholipidosis; resveratrol; reactive oxygen species; VEGF. hal-00514897,version1 the protective effects of resveratrol (Rsv: 1 µM), a polyphenol from red wine. Methods: ARPE-19 cells were

Paris-Sud XI, Université de

188

The activation of protein kinase C induces higher production of reactive oxygen species by mononuclear cells in patients with multiple sclerosis than in controls  

Microsoft Academic Search

Objective: Recent findings have increasingly shown the importance of reactive oxygen species (ROS) in causing oxidative damage to macromolecules and in contributing to tissue degeneration in target organs of autoimmune diseases. This study was aimed at comparing the base line and induced production of ROS by peripheral blood mononuclear cells (PB MNCs) of patients with multiple sclerosis (MS) in remission

O. Vladimirova; F. M. Lu; L. Shawver; B. Kalman

1999-01-01

189

A general circulation model based calculation of HCl and ClNO 2 production from sea salt dechlorination: Reactive Chlorine Emissions Inventory  

Microsoft Academic Search

As part of the Global Emission Inventory Assessment Reactive Chlorine Emissions Inventory, a global model of chemical processes in the marine boundary layer, (MBL), Marine Aerosol and Gas Phase Interactions (MAGPI), was developed to calculate direct monthly production of HCl and ClNO2 from sea salt dechlorination on a 2.8 \\

David J. Erickson; Christophe Seuzaret; William C. Keene; Sun Ling Gong

1999-01-01

190

Gelidium elegans, an Edible Red Seaweed, and Hesperidin Inhibit Lipid Accumulation and Production of Reactive Oxygen Species and Reactive Nitrogen Species in 3T3-L1 and RAW264.7 Cells.  

PubMed

Gelidium elegans is an edible red alga native to the intertidal area of northeastern Asia. We investigated the effect of G.?elegans extract and its main flavonoids, rutin and hesperidin, on lipid accumulation and the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in 3T3-L1 and RAW264.7 cells. Our data show that G.?elegans extract decreased lipid accumulation and ROS/RNS production in a dose-dependent manner. The extract also inhibited the mRNA expression of adipogenic transcription factors, such as peroxisome proliferator-activated receptor gamma and CCAAT/enhancer-binding protein alpha, while enhancing the protein expression of the antioxidant enzymes superoxide dismutases 1 and 2, glutathione peroxidase, and glutathione reductase compared with controls. In addition, lipopolysaccharide-induced nitric oxide production was significantly reduced in G.?elegans extract-treated RAW264.7 cells. In analysis of the effects of G.?elegans flavonoids on lipid accumulation and ROS/RNS production, only hesperidin showed an inhibitory effect on lipid accumulation and ROS production; rutin did not affect adipogenesis and ROS status. The antiadipogenic effect of hesperidin was evidenced by the downregulation of peroxisome proliferator-activated receptor gamma, CCAAT/enhancer-binding protein alpha, and fatty acid binding protein 4 gene expression. Collectively, our data suggest that G.?elegans is a potential food source containing antiobesity and antioxidant constituents. Copyright © 2014 John Wiley & Sons, Ltd. PMID:24930594

Jeon, Hui-Jeon; Seo, Min-Jung; Choi, Hyeon-Son; Lee, Ok-Hwan; Lee, Boo-Yong

2014-11-01

191

Advanced glycation end products delay corneal epithelial wound healing through reactive oxygen species generation.  

PubMed

Delayed healing of corneal epithelial wounds is a serious complication in diabetes. Advanced glycation end products (AGEs) are intimately associated with the diabetic complications and are deleterious to the wound healing process. However, the effect of AGEs on corneal epithelial wound healing has not yet been evaluated. In the present study, we investigated the effect of AGE-modified bovine serum albumin (BSA) on corneal epithelial wound healing and its underlying mechanisms. Our data showed that AGE-BSA significantly increased the generation of intracellular ROS in telomerase-immortalized human corneal epithelial cells. However, the generation of intracellular ROS was completely inhibited by antioxidant N-acetylcysteine (NAC), anti-receptor of AGEs (RAGE) antibodies, or the inhibitor of NADPH oxidase. Moreover, AGE-BSA increased NADPH oxidase activity and protein expression of NADPH oxidase subunits, p22phox and Nox4, but anti-RAGE antibodies eliminated these effects. Furthermore, prevention of intracellular ROS generation using NAC or anti-RAGE antibodies rescued AGE-BSA-delayed epithelial wound healing in porcine corneal organ culture. In conclusion, our results demonstrated that AGE-BSA impaired corneal epithelial wound healing ex vivo. AGE-BSA increased intracellular ROS generation through NADPH oxidase activation, which accounted for the delayed corneal epithelial wound healing. These results may provide better insights for understanding the mechanism of delayed healing of corneal epithelial wounds in diabetes. PMID:23955437

Shi, Long; Chen, Hongmei; Yu, Xiaoming; Wu, Xinyi

2013-11-01

192

Efficient cyanoaromatic photosensitizers for singlet oxygen production: synthesis and characterization of the transient reactive species.  

PubMed

In order to graft cyanoaromatic molecules onto various inert supports, we designed two new cyanoanthracene derivatives of benzo[b]triphenylene-9,14-dicarbonitrile (DBTP, 1), which already demonstrated good photosensitizing properties. We synthesized 3-(N-hydroxypropyl)carboxamido-9,14-dicyanobenzo[b]triphenylene, 3 and 3-(N-N0-Boc-aminohexyl)carboxamido-9,14-dicyanobenzo[b]triphenylene, 4 and compared their photophysical properties in acetonitrile relative to those of the parent compound 1 and its carboxylic derivative 9,14-dicyanobenzo[b]triphenylene-3-carboxylic acid, 2. The transient species were analysed and the quantum yields of singlet oxygen production (??) determined in acetonitrile. The effect of chemical functionalization can be considered negligible, since absorption spectra, fluorescence emission spectra and fluorescence lifetimes do not significantly change with the substituent. The triplet-triplet absorption spectra and the triplet excited state lifetimes are similar for the whole series. For compounds 1-4 high values of ??, close to that of the standard sensitizer 1H-phenalen-1-one (PN, ?? ? 1), and higher than that of the well-known photosensitizer 9,10-dicyanoanthracene (DCA), are due to very efficient intersystem crossing from the singlet to the triplet excited state and subsequent energy transfer to ground state oxygen ((3)O2). They belong to a class of very efficient photosensitizers, absorbing visible light and stable under irradiation, they may be functionalized without significant changes to their photophysical behaviour, and grafted onto various supports. PMID:24013434

Ronzani, Filippo; Arzoumanian, Emmanuel; Blanc, Sylvie; Bordat, Patrice; Pigot, Thierry; Cugnet, Cyril; Oliveros, Esther; Sarakha, Mohamed; Richard, Claire; Lacombe, Sylvie

2013-10-28

193

Antioxidant-photosensitizer dual-loaded polymeric micelles with controllable production of reactive oxygen species.  

PubMed

Poly(ethylene glycol)-b-poly(caprolactone) (PEG-b-PCL) micelles dually loaded with both pheophorbide a (PhA) as a photosensitizer and ?-carotene (CAR) as a singlet oxygen ((1)O2) scavenger were designed to control photodynamic therapy (PDT) activity in cancer treatment. The CAR in the PhA/CAR micelles significantly diminished PhA-generated (1)O2 through direct (1)O2 scavenging, whereas the CAR molecules lost their (1)O2 scavenging activity when the PhA and CAR were spatially isolated by the disintegration of the PEG-b-PCL micelles. In cell-culture systems, light irradiation at a post-treatment time that corresponded to the presence of the micelles in the blood environment induced negligible phototoxicity, whereas light irradiation at a post-treatment time that corresponded to the presence of the micelles in the intracellular environment induced remarkable phototoxicity. In addition, a longer post-treatment time induced greater internalization of PhA/CAR micelles, which resulted in higher phototoxicity, suggesting an increase in photo killing activity against the tumor cells of interest. Thus, the co-loading of a (1)O2 generator and a (1)O2 scavenger into a single micelle is a potential strategy that may be useful in facilitating more accurate and reliable PDT with site-specific controllable production of singlet oxygen species for cancer treatment. PMID:24939615

Li, Li; Cho, Hana; Yoon, Kwon Hyeok; Kang, Han Chang; Huh, Kang Moo

2014-08-25

194

The Use of HRP in Decolorization of Reactive Dyes and Toxicological Evaluation of Their Products  

PubMed Central

This work studied the potential use of horseradish peroxidase (HRP) in the decolorization of the following textile dyes: Drimarene Blue X-3LR (DMBLR), Drimarene Blue X-BLN (DMBBLN), Drimarene Rubinol X-3LR (DMR), and Drimarene Blue CL-R (RBBR). Dyes were individually tested in the reaction media containing 120?mg·L?1, considering the following parameters: temperature (20–45°C), H2O2 concentration (0–4.44?mmol·L?1), and reaction time (5 minutes, 1 and 24?h). The following conditions: 35°C, 0.55?mmol·L?1, and 1h, provided the best set of results of color removal for DMBLR (99%), DMBBLN (77%), DMR (94%), and RBBR (97%). It should be mentioned that only 5 minutes of reaction was enough to obtain 96% of decolorization for DMBLR and RBBR. After the decolorization reactions of DMBLR, DMR, and RBBR, it was possible to observe the reduction of Artemia salina mortality and the no significant increase in toxicity for the products generated from DMBBLN. PMID:21318147

da Silva, Michelle Reis; de Sa, Livian Ribeiro Vasconcelos; Russo, Carlos; Scio, Elita; Ferreira-Leitao, Viridiana Santana

2010-01-01

195

Chronic Aldosterone Administration Causes NOX2-Mediated Increases In Reactive Oxygen Species Production and Endothelial Dysfunction in the Cerebral Circulation  

PubMed Central

Objective An elevated plasma aldosterone level is an independent cardiovascular risk factor. Although excess aldosterone promotes cardiovascular disease, no studies have examined the effect of increased plasma aldosterone on the cerebral circulation. A major source of vascular reactive oxygen species (ROS) during cardiovascular disease is the NADPH oxidases. Because NOX2-containing NADPH oxidase (NOX2 oxidase) is highly expressed in cerebral endothelium, we postulated that it might contribute to ROS generation and vascular dysfunction in response to aldosterone. Here we examined the effect of aldosterone and NOX2 oxidase on ROS production and endothelial dysfunction in the cerebral circulation, and whether the effects of aldosterone are exacerbated in aged mice. Methods and Results In adult (average age ~24–25 wk) wild-type (WT) and Nox2-deficient (Nox2?/y) mice, neither vehicle nor aldosterone (0.28 mg/kg/day for 14 days) affected blood pressure (measured using tail-cuff). By contrast, aldosterone treatment reduced dilation of the basilar artery (measured using myography) to the endothelium-dependent agonist acetylcholine in WT mice (P<0.05), but had no such effect in NOX2?/y mice (P>0.05). Aldosterone increased basal and phorbol-dibutyrate stimulated superoxide production (measured using L-012-enhanced chemiluminesence) in cerebral arteries from WT but not Nox2?/y mice. In aged WT mice (average age ~70 wk), aldosterone treatment increased blood pressure, but had a similar effect on cerebral artery superoxide levels as in adult WT mice. Conclusions These data indicate that NOX2 oxidase mediates aldosterone-induced increases in ROS production and endothelial dysfunction in cerebral arteries from adult mice independently of blood pressure changes. Aldosterone-induced hypertension is augmented during aging. PMID:24991871

CHRISSOBOLIS, Sophocles; DRUMMOND, Grant R.; FARACI, Frank M.; SOBEY, Christopher G.

2014-01-01

196

The production of reactive oxygen species by irradiated camphorquinone-related photosensitizers and their effect on cytotoxicity.  

PubMed

Camphorquinone (CQ) is widely used as an initiator in modern light-cured resin systems but there are few reports about its effects on living cells. To clarify the mechanism of photosensitizer-induced cytotoxicity, the production of initiator radicals and subsequent reactive oxygen species (ROS) by CQ, benzil (BZ), benzophenone (BP), 9-fluorenone (9-F) in the presence of the reducing agent (2-dimethylaminoethyl methacrylate or N,N-dimethyl-p-toluidine, DMT) with visible-light irradiation was examined in a cell or cell-free system. Initiator radical production was estimated by the reduction rate of 1,1-diphenyl-2-picrylhydrazyl and by the conversion of poly-triethyleneglycol dimethacrylate; the results indicated that CQ/DMT had the highest activity among them. The cytotoxic effects of the photosensitizers on both human submandibular gland (HSG) adenocarcinoma cell line and primary human gingival fibroblast (HGF) showed that the 50% toxic concentration (TC(50)) declined in the order: CQ>BP>9-F>BZ. ROS produced in HSG or HGF cells by elicited, irradiated photosensitizers were evaluated in two different assays, one using adherent cell analysis and sorting cytometry against adherent cells and the other, flow cytometry against floating cells, with fluorescent probes. ROS production was dose- and time- dependent, and declined in the order: BZ>9-F>BP>CQ. Cytotoxic activity was correlated with the amount of ROS. Cytotoxicity and ROS generation in HGF cells was significantly lower than in HSG cells. ROS induced by aliphatic ketones (CQ) were efficiently scavenged by hydroquinone and vitamin E, whereas those by aromatic ketones (9-F) were diminished by mannitol and catalase, suggesting that OH radicals were involved in ROS derived from 9-F. A possible link between the cytotoxic activity and ROS is suggested. PMID:11286804

Atsumi, T; Iwakura, I; Fujisawa, S; Ueha, T

2001-05-01

197

Extending Cassava Root Shelf Life via Reduction of Reactive Oxygen Species Production1[C][W][OA  

PubMed Central

One of the major constraints facing the large-scale production of cassava (Manihot esculenta) roots is the rapid postharvest physiological deterioration (PPD) that occurs within 72 h following harvest. One of the earliest recognized biochemical events during the initiation of PPD is a rapid burst of reactive oxygen species (ROS) accumulation. We have investigated the source of this oxidative burst to identify possible strategies to limit its extent and to extend cassava root shelf life. We provide evidence for a causal link between cyanogenesis and the onset of the oxidative burst that triggers PPD. By measuring ROS accumulation in transgenic low-cyanogen plants with and without cyanide complementation, we show that PPD is cyanide dependent, presumably resulting from a cyanide-dependent inhibition of respiration. To reduce cyanide-dependent ROS production in cassava root mitochondria, we generated transgenic plants expressing a codon-optimized Arabidopsis (Arabidopsis thaliana) mitochondrial alternative oxidase gene (AOX1A). Unlike cytochrome c oxidase, AOX is cyanide insensitive. Transgenic plants overexpressing AOX exhibited over a 10-fold reduction in ROS accumulation compared with wild-type plants. The reduction in ROS accumulation was associated with a delayed onset of PPD by 14 to 21 d after harvest of greenhouse-grown plants. The delay in PPD in transgenic plants was also observed under field conditions, but with a root biomass yield loss in the highest AOX-expressing lines. These data reveal a mechanism for PPD in cassava based on cyanide-induced oxidative stress as well as PPD control strategies involving inhibition of ROS production or its sequestration. PMID:22711743

Zidenga, Tawanda; Leyva-Guerrero, Elisa; Moon, Hangsik; Siritunga, Dimuth; Sayre, Richard

2012-01-01

198

Characterization and re-use potential of by-products generated from the Ohio State Carbonation and Ash Reactivation (OSCAR) process  

Microsoft Academic Search

Two novel sorbents (i.e. “regenerated sorbent” and “supersorbent”) for dry flue gas desulfurization were tested, and by-products characterized, using a pilot-scale version of the Ohio State Carbonation and Ash Reactivation (OSCAR) process. The main elements of the process consisted of sorbent production, a riser reactor, cyclone and baghouse. Trace elements, including As, Se and Hg, were found at higher levels

Panuwat Taerakul; Ping Sun; Danold W. Golightly; Harold W. Walker; Linda K. Weavers; Behrad Zand; Tarunjit Butalia; Theodore J. Thomas; Himanshu Gupta; Liang-Shih Fan

2007-01-01

199

Rehydration of the Lichen Ramalina lacera Results in Production of Reactive Oxygen Species and Nitric Oxide and a Decrease in Antioxidants  

PubMed Central

Lichens are slow-growing associations of fungi and unicellular green algae or cyanobacteria. They are poikilohydric organisms whose lifestyle in many cases consists of alternating periods of desiccation, with low metabolic activity, and hydration, which induces increase in their metabolism. Lichens have apparently adapted to such extreme transitions between desiccation and rehydration, but the mechanisms that govern these adaptations are still poorly understood. In this study, the effect of rehydration on the production of reactive oxygen species and nitric oxide as well as low-molecular-weight antioxidants was investigated with the lichen Ramalina lacera. Rehydration of R. lacera resulted in the initiation of and a rapid increase in photosynthetic activity. Recovery of photosynthesis was accompanied by bursts of intracellular production of reactive oxygen species and nitric oxide. Laser-scanning confocal microscopy using dichlorofluorescein fluorescence revealed that formation of reactive oxygen species following rehydration was associated with both symbiotic partners of the lichen. The rate and extent of reactive oxygen species production were similar in the light and in the dark, suggesting a minor contribution of photosynthesis. Diaminofluorescein fluorescence, indicating nitric oxide formation, was detected only in fungal hyphae. Activities associated with rehydration did not have a deleterious effect on membrane integrity as assessed by measurement of electrolyte leakage, but water-soluble low-molecular-weight antioxidants decreased significantly. PMID:15812046

Weissman, Lior; Garty, Jacob; Hochman, Ayala

2005-01-01

200

Production of hybrid diesel fuel precursors from carbohydrates and petrochemicals using formic acid as a reactive solvent.  

PubMed

We report the one-pot alkylation of mesitylene with carbohydrate-derived 5-(hydroxymethyl)furfural (HMF) as a step toward diesel-range liquids. Using FeCl(3) as a catalyst, HMF is shown to alkylate toluene, xylene, and mesitylene in high yields in CH(2)Cl(2) and MeNO(2) solvents. Efforts to extend this reaction to greener or safer solvents showed that most ether-based solvents are unsatisfactory. Acid catalysts (e.g, p-TsOH) also proved to be ineffective. Using formic acid as a reactive solvent, mesitylene could be alkylated to give mesitylmethylfurfural (MMF) starting from fructose with yields up to approximately 70 %. The reaction of fructose with formic acid in the absence of mesitylene gave rise to low yields of the formate ester of HMF, which indicates the stabilizing effect of replacing the hydroxyl substituent with mesityl. The arene also serves as a second phase into which the product is extracted. Even by using formic acid, the mesitylation of less expensive precursors such as glucose and cellulose proceeded only in modest yields (ca. 20 %). These simpler substrates were found to undergo mesitylation by using hydrogen chloride/formic acid via the intermediate chloromethylfurfural. PMID:23281330

Zhou, Xiaoyuan; Rauchfuss, Thomas B

2013-02-01

201

Fc?R-driven Release of IL-6 by Macrophages Requires NOX2-dependent Production of Reactive Oxygen Species  

PubMed Central

Activation of the Fc?R via antigen containing immune complexes can lead to the generation of reactive oxygen species, which are potent signal transducing molecules. However, whether ROS contribute to Fc?R signaling has not been studied extensively. We set out to elucidate the role of NADPH oxidase-generated ROS in macrophage activation following Fc?R engagement using antigen-containing immune complexes. We hypothesized that NOX2 generated ROS is necessary for propagation of downstream Fc?R signaling and initiation of the innate immune response. Following exposure of murine bone marrow-derived macrophages (BMDMs) to inactivated Francisella tularensis (iFt)-containing immune complexes, we observed a significant increase in the innate inflammatory cytokine IL-6 at 24 h compared with macrophages treated with Ft LVS-containing immune complexes. Ligation of the Fc?R by opsonized Ft also results in significant ROS production. Macrophages lacking the gp91phox subunit of NOX2 fail to produce ROS upon Fc?R ligation, resulting in decreased Akt phosphorylation and a reduction in the levels of IL-6 compared with wild type macrophages. Similar results were seen following infection of BMDMs with catalase deficient Ft that fail to scavenge hydrogen peroxide. In conclusion, our findings demonstrate that ROS participate in elicitation of an effective innate immune in response to antigen-containing immune complexes through Fc?R. PMID:23857584

Franchini, Anthony M.; Hunt, Danielle; Melendez, J. Andres; Drake, James R.

2013-01-01

202

Iron oxide nanoparticles induce human microvascular endothelial cell permeability through reactive oxygen species production and microtubule remodeling  

PubMed Central

Background Engineered iron nanoparticles are being explored for the development of biomedical applications and many other industry purposes. However, to date little is known concerning the precise mechanisms of translocation of iron nanoparticles into targeted tissues and organs from blood circulation, as well as the underlying implications of potential harmful health effects in human. Results The confocal microscopy imaging analysis demonstrates that exposure to engineered iron nanoparticles induces an increase in cell permeability in human microvascular endothelial cells. Our studies further reveal iron nanoparticles enhance the permeability through the production of reactive oxygen species (ROS) and the stabilization of microtubules. We also showed Akt/GSK-3? signaling pathways are involved in iron nanoparticle-induced cell permeability. The inhibition of ROS demonstrate ROS play a major role in regulating Akt/GSK-3? – mediated cell permeability upon iron nanoparticle exposure. These results provide new insights into the bioreactivity of engineered iron nanoparticles which can inform potential applications in medical imaging or drug delivery. Conclusion Our results indicate that exposure to iron nanoparticles induces an increase in endothelial cell permeability through ROS oxidative stress-modulated microtubule remodeling. The findings from this study provide new understandings on the effects of nanoparticles on vascular transport of macromolecules and drugs. PMID:19134195

Apopa, Patrick L; Qian, Yong; Shao, Rong; Guo, Nancy Lan; Schwegler-Berry, Diane; Pacurari, Maricica; Porter, Dale; Shi, Xianglin; Vallyathan, Val; Castranova, Vincent; Flynn, Daniel C

2009-01-01

203

Cordycepin inhibits albumin-induced epithelial-mesenchymal transition of renal tubular epithelial cells by reducing reactive oxygen species production.  

PubMed

Albumin induced epithelial-mesenchymal transition (EMT) of renal tubular cells through reactive oxygen species (ROS) pathway plays an important role in tubulointerstitial fibrosis. Cordycepin (3 -deoxyadenosine), a potential antioxidant, was demonstrated to have various pharmacological effects and could inhibit EMT of some cells. However, the role of cordycepin on albumin-induced EMT in renal tubular cells (HK2) is unclear. In this study, we investigated the effect of cordycepin on albumin-induced EMT of HK2 cells and its mechanisms. HK-2 cells were exposed to bovine serum albumin with or without pretreatment with cordycepin. Results showed that albumin significantly induced EMT formation of HK-2 which associated with NADPH oxidase activation and intracellular ROS overproduction through increased Rac1 activity and expression of NOX4, p22phox and p47phox, while these effects were abolished in that pretreated with cordycepin. In conclusion, cordycepin could ameliorate albumin-induced EMT of HK2 cells by decreasing NADPH oxidase activity and inhibiting ROS production. PMID:22149621

Xiao, Li; Ge, Yan; Sun, Lin; Xu, Xiaoxuan; Xie, Ping; Zhan, Ming; Wang, Ming; Dong, Zheng; Li, Jun; Duan, Shaobin; Liu, Fuyou; Xiao, Ping

2012-02-01

204

Angiotensin II-Induced Production of Mitochondrial Reactive Oxygen Species: Potential Mechanisms and Relevance for Cardiovascular Disease  

PubMed Central

Abstract Significance: The role of reactive oxygen species (ROS) in angiotensin II (AngII) induced endothelial dysfunction, cardiovascular and renal remodeling, inflammation, and fibrosis has been well documented. The molecular mechanisms of AngII pathophysiological activity involve the stimulation of NADPH oxidases, which produce superoxide and hydrogen peroxide. AngII also increases the production of mitochondrial ROS, while the inhibition of AngII improves mitochondrial function; however, the specific molecular mechanisms of the stimulation of mitochondrial ROS is not clear. Recent Advances: Interestingly, the overexpression of mitochondrial thioredoxin 2 or mitochondrial superoxide dismutase attenuates AngII-induced hypertension, which demonstrates the importance of mitochondrial ROS in AngII-mediated cardiovascular diseases. Critical Issues: Although mitochondrial ROS plays an important role in normal physiological cell signaling, AngII, high glucose, high fat, or hypoxia may cause the overproduction of mitochondrial ROS, leading to the feed-forward redox stimulation of NADPH oxidases. This vicious cycle may contribute to the development of pathological conditions and facilitate organ damage in hypertension, atherosclerosis, and diabetes. Future Directions: The development of antioxidant strategies specifically targeting mitochondria could be therapeutically beneficial in these disease conditions. Antioxid. Redox Signal. 19, 1085–1094. PMID:22443458

Nazarewicz, Rafal R.

2013-01-01

205

Exposure to lambda-cyhalothrin, a synthetic pyrethroid, increases reactive oxygen species production and induces genotoxicity in rat peripheral blood.  

PubMed

Lambda-cyhalothrin (LTC) is a synthetic pyrethroid with a broad spectrum of insecticidal and acaricidal activities used to control a wide range of insect pests in a variety of applications. However, there is little known about its adverse effects, in particular those related to its genotoxicity in humans. To elucidate the genotoxicity mechanisms of LTC, the micronuclei (MN) frequencies, the levels of reactive oxygen species (ROS), erythrocyte osmotic fragility, nitrite (NO) formation, protein carbonyl (PCO) levels and malondialdehyde (MDA) production were evaluated for a period of 7, 14 and 21 days. Our results show that exposure rat to LTC (1/10DL50 = 6.23 mg/kg) for a period of 7, 14 and 21 days induced a noticeable genotoxic effect in rat peripheral blood evidenced by a significant increase in the frequency of MN only at day 21 of treatment. Significant differences between the two groups were observed in erythrocyte osmotic fragility. Further, a significant (p < 0.01) increase in ROS contents, NO formation, PCO levels and lipid peroxidation in erythrocytes were observed at different times of treatments, suggesting the implication of oxidative stress in its toxicity. These results confirm the genotoxic and the pro-oxidant effects of LTC in rat peripheral blood. PMID:23406951

Fetoui, Hamadi; Feki, Ameni; Ben Salah, Ghada; Kamoun, Hassen; Fakhfakh, Feiza; Gdoura, Radhouane

2013-02-13

206

A Novel Nontoxic Inhibitor of the Activation of NADPH Oxidase Reduces Reactive Oxygen Species Production in Mouse LungS?  

PubMed Central

1-Hexadecyl-3-trifluoroethylglycero-sn-2-phosphomethanol (MJ33) is a fluorinated phospholipid analog that inhibits the phospholipase A2 (PLA2) activity of peroxiredoxin 6 (Prdx6). Prdx6 PLA2 activity is required for activation of NADPH oxidase 2 and subsequent generation of reactive oxygen species (ROS). In vitro, MJ33 inhibited agonist-stimulated production of ROS by the isolated perfused mouse lung, lung microvascular endothelial cells, and polymorphonuclear leukocytes. MJ33 (0.02–0.5 µmol MJ33/kg body weight) in mixed unilamellar liposomes was administered to C57BL/6 mice by either intratracheal (i.t.) or i.v. routes. Lung MJ33 content, measured by liquid chromatography/mass spectroscopy, showed uptake of 67–87% of the injected dose for i.t. and 23–42% for i.v. administration at 4 hours postinjection. PLA2 activity of lung homogenates was markedly inhibited (>85%) at 4 hours postadministration. Both MJ33 content and PLA2 activity gradually returned to near control levels over the subsequent 24–72 hours. Mice treated with MJ33 at 12.5–25 µmol/kg did not show changes (compared with control) in clinical symptomatology, body weight, hematocrit, and histology of lung, liver, and kidney during a 30- to 50-day observation period. Thus, the toxic dose of MJ33 was >25 µmol/kg, whereas the PLA2 inhibitory dose was approximately 0.02 µmol/kg, indicating a high margin of safety. MJ33 administered to mice prior to lung isolation markedly reduced ROS production and tissue lipid and protein oxidation during ischemia followed by reperfusion. Thus, MJ33 could be useful as a therapeutic agent to prevent ROS-mediated tissue injury associated with lung inflammation or in harvested lungs prior to transplantation. PMID:23475902

Lee, Intae; Dodia, Chandra; Chatterjee, Shampa; Zagorski, John; Mesaros, Clementina; Blair, Ian A.; Feinstein, Sheldon I.; Jain, Mahendra

2013-01-01

207

Increase in reactive oxygen species production and phagocytic activity of polymorphonuclear neutrophils stimulated by preirradiated hematoporphyrin-derivative solution  

NASA Astrophysics Data System (ADS)

We have studied the influence of preirradiated by visible light hematoporphyrin derivative (HpD) solution in PBS on the production of reactive oxygen species (ROS) and phagocytosis of latex particles by rat peritoneal polymorphonuclear neutrophils (PMN), and also on the delayed type hypersensitivity reaction (DTH) to sheep red blood cells in mice. The release of ROS and phagocytic activity were observed by means of registration of the luminol- enhanced chemiluminescence (ChL) in the absence and the in the presence of latex particles. Non-irradiated HpD did not influence neither spontaneous ChL response, nor latex- activated. HpD preirradiated by 135 J/m2 did not affect spontaneous, but increased latex-activated ChL response by 20 percent. This fact indicates an increase in PMN phagocytic activity under the treatment with preirradiated HpD. Increase in preirradiation fluence up to 8.1 kJ/m2 resulted in significant enhancement of spontaneous ChL and inhibition of latex-activated ChL response of PMN. Results of spectroscopic analysis showed negligible decease in HpD Soret band after preirradiation of HpD by the highest fluences used in this study. We could not detect any significant photoproduct formation by differential absorption spectroscopy. Earlier, we have propose the photoinduced aggragation as one of the possible mechanisms of photodegradation of aqueous porphyrin solutions. In all probability, the increase in ROS production by PMN, treated with preirradiated HpD can be attributed to the phagocytosis of aggregates formed. It is possible that ROS can influence directly the DTH-effector cells leading to the observed decrease in DTH reaction level.

Melnikova, Vladislava; Bezdetnaya, Lina N.; Belitchenko, Irina; Kyagova, Alla A.; Colosetti, Pascal; Potapenko, Alexander Y.; Guillemin, Francois H.

1997-05-01

208

Inclusive D*-meson production in ep scattering at low Q2 in the GM-VFN scheme at NLO  

E-print Network

We have calculated the next-to-leading order cross sections for the inclusive production of D*-mesons in ep collisions at HERA for finite, although very small Q2. In this Q2-range, the same approximations as for photoproduction can be used. Our calculation is performed in the general-mass variable-flavour-number scheme. In this approach, large logarithms of the charm transverse momentum are resummed and finite terms depending on m^2/p_T^2 are kept in the hard scattering cross sections. The theoretical results are compared with recent data from the ZEUS collaboration at HERA. On average, we find good agreement.

G. Kramer; H. Spiesberger

2009-06-15

209

Coarse-grained potential analysis of neutron-proton and proton-proton scattering below the pion production threshold  

NASA Astrophysics Data System (ADS)

Using the ?-shell representation we present a successful fit to neutron-proton and proton-proton scattering data below the pion production threshold. A detailed overview of the theory necessary to calculate observables with this potential is presented. A new data selection process is used to obtain the largest mutually consistent data base. The analysis includes data within the years 1950 to 2013. Using 46 parameters we obtain ?2/Ndata=1.04 with Ndata=6713 including normalization data. Phase shifts with error bars are provided.

Pérez, R. Navarro; Amaro, J. E.; Arriola, E. Ruiz

2013-12-01

210

A process for enhancing the accessibility and reactivity of hardwood kraft-based dissolving pulp for viscose rayon production by cellulase treatment.  

PubMed

The commercial pre-hydrolysis kraft-based dissolving pulp production process can be a typical example for the demonstration/implementation of the integrated forest biorefinery concept. In this study, the concept of cellulase treatment of this dissolving pulp for enhancement of accessibility/reactivity in terms of viscose rayon production was demonstrated. The cellulase treatment resulted in the formation of additional openings/surface areas in the fiber structure via the possible action of "etching". As a result, the pore volume of pulp fibers increased, which led to the increase in the accessibility to xanthation, and thus Fock reactivity. Results showed that the cellulase treatment was effective in increasing the Fock reactivity, at a cellulase dosage of 2u/g (based on the dry weight of pulp), the Fock reactivity increased from 47.67% to 79.9%. The adoption of cellulase treatment to hardwood kraft-based dissolving pulp can provide an efficient approach for enhancing its performance in the commercial viscose-rayon process. PMID:24384317

Miao, Qingxian; Chen, Lihui; Huang, Liulian; Tian, Chao; Zheng, Linqiang; Ni, Yonghao

2014-02-01

211

Contributions of reactive oxygen species and mitogen-activated protein kinase signaling in arsenite-stimulated hemeoxygenase-1 production  

SciTech Connect

Hemeoxygenase-1 (HO-1) is an oxidative stress responsive gene upregulated by various physiological and exogenous stimuli. HO-1 has cytoprotective activities and arsenite is a potent inducer of HO-1 in many cell types and tissues, including epidermal keratinocytes. We investigated the potential contributions of reactive oxygen species (ROS) generation and mitogen-activated protein kinase (MAPK) activation to arsenite-dependent regulation of HO-1 in HaCaT cells, an immortalized human keratinocyte line. Both epidermal growth factor (EGF) and arsenite stimulated ROS production was detected by dihydroethidium (DHE) staining and fluorescence microscopy. Arsenite induced HO-1 in a time- and concentration-dependent manner, while HO-1 expression in response to EGF was modest and evident at extended time points (48-72 h). Inhibition of EGF receptor, MEK I/II or Src decreased arsenite-stimulated HO-1 expression by 20-30%. In contrast, addition of a superoxide scavenger or inhibition of p38 activity decreased the arsenite-dependent response by 80-90% suggesting that ROS and p38 are required for HO-1 induction. However, ROS generation alone was insufficient for the observed arsenite-dependent response as use of a xanthine/xanthine oxidase system to generate ROS did not produce an equivalent upregulation of HO-1. Cooperation between ERK signaling and ROS generation was demonstrated by synergistic induction of HO-1 in cells co-treated with EGF and xanthine/xanthine oxidase resulting in a response nearly equivalent to that observed with arsenite. These findings suggest that the ERK/MAPK activation is necessary but not sufficient for optimal arsenite-stimulated HO-1 induction. The robust and persistent upregulation of HO-1 may have a role in cellular adaptation to chronic arsenic exposure.

Cooper, Karen L. [MSC09 5360, 1 University of New Mexico Health Sciences Center, Program in Toxicology, College of Pharmacy, Albuquerque, NM 87131 (United States); Liu, Ke Jian [MSC09 5360, 1 University of New Mexico Health Sciences Center, Program in Toxicology, College of Pharmacy, Albuquerque, NM 87131 (United States); Hudson, Laurie G. [MSC09 5360, 1 University of New Mexico Health Sciences Center, Program in Toxicology, College of Pharmacy, Albuquerque, NM 87131 (United States)]. E-mail: lhudson@salud.unm.edu

2007-01-15

212

Cancer-derived immunoglobulin G promotes tumor cell growth and proliferation through inducing production of reactive oxygen species  

PubMed Central

Cancer cells have been found to express immunoglobulin G (IgG), but the exact functions and underlying mechanisms of cancer-derived IgG remain elusive. In this study, we first confirmed that downregulation of IgG restrained the growth and proliferation of cancer cells in vitro and in vivo. To elucidate its mechanism, we carried out a co-immunoprecipitation assay in HeLa cells and identified 27 potential IgG-interacting proteins. Among them, receptor of activated protein kinase C 1 (RACK1), ras-related nuclear protein (RAN) and peroxiredoxin 1 (PRDX1) are closely related to cell growth and oxidative stress, which prompted us to investigate the mechanism of action of IgG in the above phenomena. Upon confirmation of the interactions between IgG and the three proteins, further experiments revealed that downregulation of cancer-derived IgG lowered levels of intracellular reactive oxygen species (ROS) by enhancing cellular total antioxidant capacity. In addition, a few ROS scavengers, including catalase (CAT), dimethylsulfoxide (DMSO), n-acetylcysteine (NAC) and superoxide dismutase (SOD), further inhibited the growth of IgG-deficient cancer cells through suppressing mitogen-activated protein kinase/extracellular-regulated kinase (MAPK/ERK) signaling pathway induced by a low level of intracellular ROS, whereas exogenous hydrogen peroxide (H2O2) at low concentration promoted their survival via increasing intracellular ROS levels. Similar results were obtained in an animal model and human tissues. Taken together, our results demonstrate that cancer-derived IgG can enhance the growth and proliferation of cancer cells via inducing the production of ROS at low level. These findings provide new clues for understanding tumor proliferation and designing cancer therapy. PMID:24309932

Wang, J; Lin, D; Peng, H; Huang, Y; Huang, J; Gu, J

2013-01-01

213

Soft X-ray production by photon scattering in pulsating binary neutron star sources  

NASA Technical Reports Server (NTRS)

A new mechanism is proposed as a source of soft (less than 1 keV) radiation in binary pulsating X-ray sources, in the form of photon scattering which leaves the electron in an excited Landau level. In a plasma with parameters typical of such sources, the low-energy X-ray emissivity of this mechanism far exceeds that of bremsstrahlung. This copious source of soft photons is quite adequate to provide the seed photons needed to explain the power-law hard X-ray spectrum by inverse Comptonization on the hot electrons at the base of the accretion column.

Bussard, R. W.; Meszaros, P.; Alexander, S.

1985-01-01

214

Soft X-ray production by photon scattering in pulsating binary neutron star sources  

NASA Astrophysics Data System (ADS)

A new mechanism is proposed as a source of soft (less than 1 keV) radiation in binary pulsating X-ray sources, in the form of photon scattering which leaves the electron in an excited Landau level. In a plasma with parameters typical of such sources, the low-energy X-ray emissivity of this mechanism far exceeds that of bremsstrahlung. This copious source of soft photons is quite adequate to provide the seed photons needed to explain the power-law hard X-ray spectrum by inverse Comptonization on the hot electrons at the base of the accretion column.

Bussard, R. W.; Meszaros, P.; Alexander, S.

1985-10-01

215

First measurements of jet production rates in deep-inelastic lepton-proton scattering  

NASA Astrophysics Data System (ADS)

The first measurements of forward multijet rates in deep-inelastic lepton scattering are presented. Data were taken with a 490-GeV muon beam incident on a hydrogen target. The jets were defined using the gade algorithm. The measured rates are presented as a function of the jet resolution parameter ycut, and as a function of the virtual-photon-proton center-of-momentum energy W, in the range 13<=W<=33 GeV. Comparisons are made to the predictions of the Lund Monte Carlo programs and good agreement is obtained when QCD corrections are included in the model.

Adams, M. R.; Aïd, S.; Anthony, P. L.; Baker, M. D.; Bartlett, J.; Bhatti, A. A.; Braun, H. M.; Busza, W.; Conrad, J. M.; Coutrakon, G.; Davisson, R.; Derado, I.; Dhawan, S. K.; Dougherty, W.; Dreyer, T.; Dziunikowska, K.; Eckardt, V.; Ecker, U.; Erdmann, M.; Eskreys, A.; Figiel, J.; Gebauer, H. J.; Geesaman, D. F.; Gilman, R.; Green, M. C.; Haas, J.; Halliwell, C.; Hanlon, J.; Hantke, D.; Hughes, V. W.; Jackson, H. E.; Jaffe, D. E.; Jancso, G.; Jansen, D. M.; Kaufman, S.; Kennedy, R. D.; Kobrak, H. G.; Krzywdzinski, S.; Kunori, S.; Lord, J. J.; Lubatti, H. J.; McLeod, D.; Magill, S.; Malecki, P.; Manz, A.; Michael, D. G.; Mohr, W.; Montgomery, H. E.; Morfin, J. G.; Nickerson, R. B.; O'day, S.; Olkiewicz, K.; Osborne, L.; Papavassiliou, V.; Pawlik, B.; Pipkin, F. M.; Ramberg, E. J.; Röser, A.; Ryan, J.; Salgado, C. W.; Salvarani, A.; Schellman, H.; Schmitz, N.; Schüler, K. P.; Seyerlein, H. J.; Skuja, A.; Snow, G. A.; Söldner-Rembold, S.; Steinberg, P. H.; Stier, H. E.; Stopa, P.; Swanson, R. A.; Talaga, R.; Tentindo-Repond, S.; Trost, H.-J.; Venkataramania, H.; Vidal, M.; Wilhelm, M.; Wilkes, J.; Wilson, Richard; Wittek, W.; Wolbers, S. A.; Zhao, T.

1992-08-01

216

First measurements of jet production rates in deep-inelastic lepton-proton scattering  

SciTech Connect

The first measurements of forward multijet rates in deep-inelastic lepton scattering are presented. Data were taken with a 490-GeV muon beam incident on a hydrogen target. The jets were defined using the GADE algorithm. The measured rates are presented as a function of the jet resolution parameter {ital y}{sub cut}, and as a function of the virtual-photon--proton center-of-momentum energy {ital W}, in the range 13{le}{ital W}{le}33 GeV. Comparisons are made to the predictions of the Lund Monte Carlo programs and good agreement is obtained when QCD corrections are included in the model.

Adams, M.R.; Aied, S.; Anthony, P.L.; Baker, M.D.; Bartlett, J.; Bhatti, A.A.; Braun, H.M.; Busza, W.; Conrad, J.M.; Coutrakon, G.; Davisson, R.; Derado, I.; Dhawan, S.K.; Dougherty, W.; Dreyer, T.; Dziunikowska, K.; Eckardt, V.; Ecker, U.; Erdmann, M.; Eskreys, A.; Figiel, J.; Gebauer, H.J.; Geesaman, D.F.; Gilman, R.; Green, M.C.; Haas, J.; Halliwell, C.; Hanlon, J.; Hantke, D.; Hughes, V.W.; Jackson, H.E.; Jaffe, D.E.; Jancso, G.; Jansen, D.M.; Kaufman, S.; Kennedy, R.D.; Kobrak, H.G.E.; Krzywdzinski, S.; Kunori, S.; Lord, J.J.; Lubatti, H.J.; McLeod, D.; Magill, S.; Malecki, P.; Manz, A.; Michael, D.G.; Mohr, W.; Montgomery, H.E.; Morfin, J.G.; Nickerson, R.B.; O'Day, S.; Olkiewicz, K.; Osborne, L.; Papavassiliou, V.; Pawlik, B.; Pipkin, F.M.; Ramberg, E.J.; Roeser, A.; Ryan, J.; Salgado, C.W.; Salvarani, A.; Schellman, H.; Schmitz, N.; Schueler, K.P.; Seyerlein, H.J.; Skuja, A.; Snow, G.A.; Soeldner-Rembold, S.; Steinberg, P.H.; Stier, H.E.; Stopa, P.; Swanson, R.A.; Talaga, R.; T; (E665 Collaboration)

1992-08-17

217

Discussion of the Role of the Extracellular Signal-Regulated Kinase-Phospholipase A 2 Pathway in Production of Reactive Oxygen Species in Alzheimer's Disease  

Microsoft Academic Search

In this paper we show that exposure of a rat brain synaptosome fraction to the amyloid beta peptide fragment ßA(25-35), but not the inverted peptide ßA(35-25), stimulated production of reactive oxygen species (ROS) in a concentration- and time-dependent manner. The ROS formation was attenuated by the tyrosine kinase inhibitor genistein, the mitogen-activated protein kinase inhibitor U0126, and the phospholipase A2

Jannike M. Andersen; Oddvar Myhre; Frode Fonnum

2003-01-01

218

Biochemical analysis of reactive oxygen species production and antioxidative responses in unripe avocado ( Persea americana Mill var Hass) fruits in response to wounding  

Microsoft Academic Search

We analyzed the production of reactive oxygen species (ROS) and of detoxifying enzymes and enzymes of the ascorbate (ASC)\\u000a acid cycle in avocado fruit (Pesea Americana Mill cv Hass) in response to wounding. The levels of superoxide anion (O2\\u000a ?), hydroxyl radicals (OH.) and hydrogen peroxide (H2O2) increased at 15 min and 2 and 15 h post-wounding. Peroxidase (POD) activity had increased

E. Castro-Mercado; Y. Martinez-Diaz; N. Roman-Tehandon; E. Garcia-Pineda

2009-01-01

219

Modification of production of reactive oxygen species in mouse peritoneal neutrophils on exposure to low-intensity modulated millimeter wave radiation  

Microsoft Academic Search

The effect of low-intensity modulated electromagnetic radiation of extremely high frequencies (EHF EMR) on the production of reactive oxygen species by mouse peritoneal neutrophils was investigated. The neutrophil activity in synergistic reaction of calcium ionophore A23187 and phorbol ester PMA was estimated by luminol-dependent chemiluminescence technique. The cells were irradiated for 20 min in the far-field zone of the channel

A. B Gapeyev; V. S Yakushina; N. K Chemeris; E. E Fesenko

1998-01-01

220

A general circulation model based calculation of HCl and ClNO2 production from sea salt dechlorination: Reactive Chlorine Emissions Inventory  

Microsoft Academic Search

As part of the Reactive Chlorine Emissions Inventory, a global model of chemical processes in the marine boundary layer (MBL), Marine Aerosol and Gas Phase Interactions (MAGPI), was developed to calculate direct monthly production of HCl and ClNO2 from sea salt dechlorination on a 2.8×2.8 latitude-longitude grid. Sea salt mass and size distributions and associated surface exchange fluxes were calculated

David J. Erickson; Christophe Seuzaret; William C. Keene; Sun Ling Gong

1999-01-01

221

On the temperature dependence of organic reactivity, nitrogen oxides, ozone production, and the impact of emission controls in San Joaquin Valley California  

NASA Astrophysics Data System (ADS)

The San Joaquin Valley (SJV) experiences some of the worst ozone air quality in the US, frequently exceeding the California 8 h standard of 70.4 ppb. To improve our understanding of trends in the number of ozone violations in the SJV, we analyze observed relationships between organic reactivity, nitrogen oxides (NOx), and daily maximum temperature in the southern SJV using measurements made as part of California at the Nexus of Air Quality and Climate Change in 2010 (CalNex-SJV). We find the daytime speciated organic reactivity with respect to OH during CalNex-SJV has a temperature-independent portion with molecules typically associated with motor vehicles being the major component. At high temperatures, characteristic of days with high ozone, the largest portion of the total organic reactivity increases exponentially with temperature and is dominated by small, oxygenated organics and molecules that are unidentified. We use this simple temperature classification to consider changes in organic emissions over the last and next decade. With the CalNex-SJV observations as constraints, we examine the sensitivity of ozone production (PO3) to future NOx and organic reactivity controls. We find that PO3 is NOx-limited at all temperatures on weekends and on weekdays when daily maximum temperatures are greater than 29 °C. As a~consequence, NOx reductions are the most effective control option for reducing the frequency of future ozone violations in the southern SJV.

Pusede, S. E.; Gentner, D. R.; Wooldridge, P. J.; Browne, E. C.; Rollins, A. W.; Min, K.-E.; Russell, A. R.; Thomas, J.; Zhang, L.; Brune, W. H.; Henry, S. B.; DiGangi, J. P.; Keutsch, F. N.; Harrold, S. A.; Thornton, J. A.; Beaver, M. R.; St. Clair, J. M.; Wennberg, P. O.; Sanders, J.; Ren, X.; VandenBoer, T. C.; Markovic, M. Z.; Guha, A.; Weber, R.; Goldstein, A. H.; Cohen, R. C.

2013-11-01

222

On the temperature dependence of organic reactivity, nitrogen oxides, ozone production, and the impact of emission controls in San Joaquin Valley, California  

NASA Astrophysics Data System (ADS)

The San Joaquin Valley (SJV) experiences some of the worst ozone air quality in the US, frequently exceeding the California 8 h standard of 70.4 ppb. To improve our understanding of trends in the number of ozone violations in the SJV, we analyze observed relationships between organic reactivity, nitrogen oxides (NOx), and daily maximum temperature in the southern SJV using measurements made as part of California at the Nexus of Air Quality and Climate Change in 2010 (CalNex-SJV). We find the daytime speciated organic reactivity with respect to OH during CalNex-SJV has a temperature-independent portion with molecules typically associated with motor vehicles being the major component. At high temperatures, characteristic of days with high ozone, the largest portion of the total organic reactivity increases exponentially with temperature and is dominated by small, oxygenated organics and molecules that are unidentified. We use this simple temperature classification to consider changes in organic emissions over the last and next decade. With the CalNex-SJV observations as constraints, we examine the sensitivity of ozone production (PO3) to future NOx and organic reactivity controls. We find that PO3 is NOx-limited at all temperatures on weekends and on weekdays when daily maximum temperatures are greater than 29 °C. As a consequence, NOx reductions are the most effective control option for reducing the frequency of future ozone violations in the southern SJV.

Pusede, S. E.; Gentner, D. R.; Wooldridge, P. J.; Browne, E. C.; Rollins, A. W.; Min, K.-E.; Russell, A. R.; Thomas, J.; Zhang, L.; Brune, W. H.; Henry, S. B.; DiGangi, J. P.; Keutsch, F. N.; Harrold, S. A.; Thornton, J. A.; Beaver, M. R.; St. Clair, J. M.; Wennberg, P. O.; Sanders, J.; Ren, X.; VandenBoer, T. C.; Markovic, M. Z.; Guha, A.; Weber, R.; Goldstein, A. H.; Cohen, R. C.

2014-04-01

223

Deep-inelastic scattering and the operator product expansion in lattice QCD  

E-print Network

We discuss the determination of deep-inelastic hadron structure in lattice QCD. By using a fictitious heavy quark, direct calculations of the Compton scattering tensor can be performed in Euclidean space that allow the extraction of the moments of structure functions. This overcomes issues of operator mixing and renormalisation that have so far prohibited lattice computations of higher moments. This approach is especially suitable for the study of the twist-two contributions to isovector quark distributions, which is practical with current computing resources. While we focus on the isovector unpolarised distribution, our method is equally applicable to other quark distributions and to generalised parton distributions. By looking at matrix elements such as $$ (where $V^\\mu$ and $A^\

William Detmold; C. -J. David Lin

2005-07-08

224

Ratio of J/? production cross sections in deep inelastic muon scattering from tin and carbon  

NASA Astrophysics Data System (ADS)

We present results on J/? production in muon interactions with tin and carbon targets at incident muon energies of 200 and 280 GeV. The ratio of cross sections per nucleon for J/? production on tin and carbon, R(Sn/C), is studied as a function of pT 2, z and x. We find an enhancement for coherent J/? production Rcoh(Sn/C) = 1.54 ± 0.07, a suppression for quasielastic production Rqe(Sn/C) = 0.79 ± 0.06 and for inelastic production Rin(Sn/C) = 1.13 ± 0.08. The inelastic cross section ratio can be interpreted within the Colour Singlet model as an enhancement of the gluon distribution in tin with respect to that in carbon. The dependence of the ratio on z and pT2 can explain the discrepancy between the results obtained in previous experiments.

Amaudruz, P.; Arneodo, M.; Arvidson, A.; Badelek, B.; Baum, G.; Beaufays, J.; Bird, I. G.; Botje, M.; Broggini, C.; Brückner, W.; Brüll, A.; Burger, W. J.; Ciborowski, J.; van Dantzig, R.; Döbbeling, H.; Domingo, J.; Drinkard, J.; Düren, M.; Engelien, H.; Ferrero, M. I.; Fluri, L.; von Harrach, D.; van der Heijden, M.; Heusch, C.; Ingram, Q.; Janson, K.; de Jong, M.; Kabuss, E. M.; Kaiser, R.; Ketel, T. J.; Klein, F.; Kullander, S.; Landgraf, U.; Lindqvist, T.; Mallot, G. K.; Mariotti, C.; van Middelkoop, G.; Mizuno, Y.; Nassalski, J.; Nowotny, D.; Peroni, C.; Povh, B.; Rieger, R.; Rith, K.; Röhrich, K.; Rondio, E.; Ropelewski, L.; Sandacz, A.; Scholz, C.; Sennhauser, U.; Sever, F.; Shibata, T.-A.; Siebler, M.; Simon, A.; Staiano, A.; Tzamouranis, Y.; Vuilleumier, J. L.; Walcher, T.; Windmolders, R.; Zetsche, F.; New Muon Collaboration (NMC)

1992-03-01

225

Black tattoo inks induce reactive oxygen species production correlating with aggregation of pigment nanoparticles and product brand but not with the polycyclic aromatic hydrocarbon content.  

PubMed

Black tattoo inks are composed of carbon nanoparticles, additives and water and may contain polycyclic aromatic hydrocarbons (PAHs). We aimed to clarify whether reactive oxygen species (ROS) induced by black inks in vitro is related to pigment chemistry, physico-chemical properties of the ink particles and the content of chemical additives and contaminants including PAHs. The study included nine brands of tattoo inks of six colours each (black, red, yellow, blue, green and white) and two additional black inks of different brands (n = 56). The ROS formation potential was determined by the dichlorofluorescein (DCFH) assay. A semiquantitative method was developed for screening extractable organic compounds in tattoo ink based on gas chromatography-mass spectrometry (GC-MS) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Two black inks produced high amounts of ROS. Peroxyl radicals accounted for up to 72% of the free radicals generated, whereas hydroxyl radicals and H?O? accounted for <14% and 16%, respectively. The same two inks aggregated strongly in water in contrast to the other black inks. They did not exhibit any shared pattern in PAHs and other organic substances. Aggregation was exclusively shared by all ink colours belonging to the same two brands. Ten of 11 black inks had PAH concentrations exceeding the European Council's recommended level, and all 11 exceeded the recommended level for benzo(a)pyrene. It is a new finding that aggregation of tattoo pigment particles correlates with ROS production and brand, independently of chemical composition including PAHs. ROS is hypothesized to be implicated in minor clinical symptoms. PMID:23800057

Høgsberg, Trine; Jacobsen, Nicklas Raun; Clausen, Per Axel; Serup, Jørgen

2013-07-01

226

Characterization of warm-reactive IgG anti-lymphocyte antibodies in systemic lupus erythematosus. Relative specificity for mitogen-activated T cells and their soluble products.  

PubMed

In addition to previously described cold-reactive IgM anti-lymphocyte antibodies maximally cytotoxic for resting cells at 15 degrees C, sera from patients with systemic lupus erythematosus (SLE) were found to contain a new type of antibody preferentially reactive at physiologic temperatures with mitogen-activated lymphocytes. This antibody lacked specificity for unstimulated lymphocytes, and was shown to be of the IgG class both by indirect immunofluorescence and in immunochemical experiments. Certain SLE sera also contained IgG antibodies with the capacity to develop plaques with mitogen-activated T lymphocyte preparations used in a reverse hemolytic plaque assay, indicating reactivity with products released by activated cells. The elimination of the ability of SLE sera to develop plaques after absorption with viable mitogen-stimulated lymphocytes, but not with resting cells, suggested that these antibodies were directed toward activation "neoantigen(s)" shed from the cell surface membrane. Surface membrane phenotype analyses performed by using a variety of monoclonal antibody reagents indicated that the plaque-forming cells (PFC) detected with SLE sera were activated T lymphocytes not restricted to single OKT4+, OKT8+, or Ia antigen+ subpopulations. Essentially all PFC expressed transferrin receptors. The present data raise the possibility that certain of the interesting effects of anti-lymphocyte antibodies on immunologic function in SLE may be mediated by interactions of these new type(s) of antibodies with activated lymphocytes or their products, rather than through blocking or depletion effects on resting precursor cells. PMID:6600174

Litvin, D A; Cohen, P L; Winfield, J B

1983-01-01

227

Diffractive production of vector mesons in Deep Inelastic Scattering within k_t-factorization approach  

E-print Network

In this work we give a theoretical description of the elastic vector meson production in diffractive DIS developed within the k_t-factorization formalism. Since the k_t-factorization scheme does not require large values of Q^2+m_V^2, we conduct an analysis that is applicable to all values of Q^2 from photo- up to highly virtual production of vector mesons. The basic quantity in this approach -- the unintegrated gluon structure function -- was for the first time extracted from the experimental data on F_{2p}, thoroughly investigated, and consistently used in the vector meson production calculation. Moreover, by limiting ourselves to the lowest Fock state of the vector meson, we were able to construct in a closed form the theory of spin-angular coupling in the vector meson. This allowed us for the first time to address the production of a vector meson in a given spin-angular state. We performed an extensive analytical and numerical investigation of the properties of 1S, 2S, and D-wave vector meson production reactions. Treating the physical ground state vector mesons as purely 1S states, we observed a good overall agreement with all available experimental data on vector meson production. For the excited states, our analysis predicts a picture which is remarkably different from 1S-state, so that such reactions can be regarded as potential sources of new information on the structure of excited states in vector mesons.

I. P. Ivanov

2003-03-06

228

The effect of high fat diet upon the production of reactive carbonyls in hypoxic heart. The effect upon connective tissue  

Microsoft Academic Search

The concentration of reactive lipid metabolites (malondialdehyde, formaldehyde, acetaldehyde and acetone) was assayed in rat heart reperfusates after 30 min ischemia in animals fed a high fat diet. A considerable increase in oxo-groups possessing metabolites was found in animals fed high fat diet as compared to animals fed a standard peletted diet or a carbohydrate enriched diet. This increased level

Zden?k Deyl

1996-01-01

229

How adding zero to the complex relation between production and scattering amplitudes found by van Beveren and Rupp gives the expected real relation  

E-print Network

If a hadronic production process is dominated by two body final state interactions, the amplitude $A$ for the production process can be expanded as a sum of the scattering amplitudes $T$ for the relevant two body channels. Van Beveren and Rupp have claimed that the unitarity relation ${\\rm {Im}} A= T^\\dag A$ can be satisfied if the coefficients in this expansion are complex. We demonstrate that the coefficients have to be real if the scattering amplitudes $T$ satisfy unitarity. Van Beveren and Rupp have merely written real coefficients as a sum of complex numbers.

M. R. Pennington; D. J. Wilson

2007-11-22

230

Double Parton Scattering in Associate Higgs Boson Production with Bottom Quarks at Hadron Colliders  

Microsoft Academic Search

Higgs boson production in association with bottom quarks, is one of the most important discovery channels for Higgs particles in the Standard Model (SM) and its supersymmetric extension at the LHC pp collider . The theoretical prediction of the corresponding cross section has been improved by including the complete next-to-leading order QCD corrections. We review the status results for the

M. Y. Hussein

2007-01-01

231

Climate and topographic controls on pasture production in a semiarid Mediterranean watershed with scattered tree cover  

NASA Astrophysics Data System (ADS)

Natural grasses in semiarid rangelands constitute an effective protection against soil erosion and degradation, are a source of natural food for livestock and play a critical role in the hydrologic cycle by contributing to the uptake and transpiration of water. However, natural pastures are threatened by land abandonment and the consequent encroachment of shrubs and trees as well as by changing climatic conditions. In spite of their ecological and economic importance, the spatio-temporal variations of pasture production at the decadal to century scales over whole watersheds are poorly known. We used a physics-based, spatially-distributed ecohydrologic model applied to a 99.5 ha semiarid watershed in western Spain to investigate the sensitivity of pasture production to climate variability. The ecohydrologic model was run using a 300 yr long synthetic daily climate dataset generated using a stochastic weather generator. The data set reproduced the range of climatic variations observed under current climate. Results indicated that variation of pasture production largely depended on factors that also determined the availability of soil moisture such as the temporal distribution of precipitation, topography, and tree canopy cover. The latter is negatively related with production, reflecting the importance of rainfall and light interception, as well as water consumption by trees. Valley bottoms and flat areas in the lower parts of the catchment are characterized by higher pasture production. A quantitative assessment of the quality of the simulations showed that ecohydrologic models are a valuable tool to investigate long term (century scale) water and energy fluxes, as well as vegetation dynamics, in semiarid rangelands.

Lozano-Parra, J.; Maneta, M. P.; Schnabel, S.

2013-12-01

232

Reactive Nitrogen Intermediates Production by Macrophages of Mycobacterium bovis- Infected Goats and Supplemented with Dyhidroxyvitamin D3 in vivo  

Microsoft Academic Search

Problem statement: Tuberculosis (TB) remains one of the world's major health problems. To evaluate in vivo indices of cellular sensitization, antigen-induced Reactive Nitrogen Intermediates (RNI) responses by blood mononuclear cells from Mycobacterium bovis BCG-infected goats supplemented with 1, 25 dyhidroxyvitamin D3 (1, 25-(OH)2D3). Approach: An experimental, longitudinal and comparative study was planned. Twelve animals of goat cattle 20-to 24-month-old sannen

Aurora Martinez-Romero; Jose Luis Ortega-Sanchez; Jose Ramon Hernandez-Salgado

233

Measurement of beauty production in deep inelastic scattering at HERA using decays into electrons  

NASA Astrophysics Data System (ADS)

The production of beauty quarks in ep interactions has been studied with the ZEUS detector at HERA for exchanged four-momentum squared Q 2>10 GeV2, using an integrated luminosity of 363 pb-1. The beauty events were identified using electrons from semileptonic b decays with a transverse momentum 0.9 < pTe < 8 GeV and pseudorapidity | ? e |<1.5. Cross sections for beauty production were measured and compared with next-to-leading-order QCD calculations. The beauty contribution to the proton structure function F 2 was extracted from the double-differential cross section as a function of Bjorken- x and Q 2.

Abramowicz, H.; Abt, I.; Adamczyk, L.; Adamus, M.; Aggarwal, R.; Antonelli, S.; Antonioli, P.; Antonov, A.; Arneodo, M.; Aushev, V.; Aushev, Y.; Bachynska, O.; Bamberger, A.; Barakbaev, A. N.; Barbagli, G.; Bari, G.; Barreiro, F.; Bartosik, N.; Bartsch, D.; Basile, M.; Behnke, O.; Behr, J.; Behrens, U.; Bellagamba, L.; Bertolin, A.; Bhadra, S.; Bindi, M.; Blohm, C.; Bokhonov, V.; Bo?d, T.; Bolilyi, O.; Boos, E. G.; Borras, K.; Boscherini, D.; Bot, D.; Boutle, S. K.; Brock, I.; Brownson, E.; Brugnera, R.; Brümmer, N.; Bruni, A.; Bruni, G.; Brzozowska, B.; Bussey, P. J.; Butterworth, J. M.; Bylsma, B.; Caldwell, A.; Capua, M.; Carlin, R.; Catterall, C. D.; Chekanov, S.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cifarelli, L.; Cindolo, F.; Contin, A.; Cooper-Sarkar, A. M.; Coppola, N.; Corradi, M.; Corriveau, F.; Costa, M.; D'Agostini, G.; Dal Corso, F.; del Peso, J.; Dementiev, R. K.; De Pasquale, S.; Derrick, M.; Devenish, R. C. E.; Dobur, D.; Dolgoshein, B. A.; Dolinska, G.; Doyle, A. T.; Drugakov, V.; Durkin, L. S.; Dusini, S.; Eisenberg, Y.; Ermolov, P. F.; Eskreys, A.; Fang, S.; Fazio, S.; Ferrando, J.; Ferrero, M. I.; Figiel, J.; Forrest, M.; Foster, B.; Fourletov, S.; Gach, G.; Galas, A.; Gallo, E.; Garfagnini, A.; Geiser, A.; Gialas, I.; Gladilin, L. K.; Gladkov, D.; Glasman, C.; Gogota, O.; Golubkov, Y. A.; Göttlicher, P.; Grabowska-Bo?d, I.; Grebenyuk, J.; Gregor, I.; Grigorescu, G.; Grzelak, G.; Gueta, O.; Gwenlan, C.; Haas, T.; Hain, W.; Hamatsu, R.; Hart, J. C.; Hartmann, H.; Hartner, G.; Hilger, E.; Hochman, D.; Hori, R.; Horton, K.; Hüttmann, A.; Iacobucci, G.; Ibrahim, Z. A.; Iga, Y.; Ingbir, R.; Ishitsuka, M.; Jakob, H.-P.; Januschek, F.; Jimenez, M.; Jones, T. W.; Jüngst, M.; Kadenko, I.; Kahle, B.; Kamaluddin, B.; Kananov, S.; Kanno, T.; Karshon, U.; Karstens, F.; Katkov, I. I.; Kaur, M.; Kaur, P.; Keramidas, A.; Khein, L. A.; Kim, J. Y.; Kisielewska, D.; Kitamura, S.; Klanner, R.; Klein, U.; Koffeman, E.; Kooijman, P.; Korol, I.; Korzhavina, I. A.; Kota?ski, A.; Kötz, U.; Kowalski, H.; Kulinski, P.; Kuprash, O.; Kuze, M.; Lee, A.; Levchenko, B. B.; Levy, A.; Libov, V.; Limentani, S.; Ling, T. Y.; Lisovyi, M.; Lobodzinska, E.; Lohmann, W.; Löhr, B.; Lohrmann, E.; Loizides, J. H.; Long, K. R.; Longhin, A.; Lontkovskyi, D.; Lukina, O. Y.; ?u?niak, P.; Maeda, J.; Magill, S.; Makarenko, I.; Malka, J.; Mankel, R.; Margotti, A.; Marini, G.; Martin, J. F.; Mastroberardino, A.; Mattingly, M. C. K.; Melzer-Pellmann, I.-A.; Mergelmeyer, S.; Miglioranzi, S.; Mohamad Idris, F.; Monaco, V.; Montanari, A.; Morris, J. D.; Mujkic, K.; Musgrave, B.; Nagano, K.; Namsoo, T.; Nania, R.; Nicholass, D.; Nigro, A.; Ning, Y.; Noor, U.; Notz, D.; Nowak, R. J.; Nuncio-Quiroz, A. E.; Oh, B. Y.; Okazaki, N.; Oliver, K.; Olkiewicz, K.; Onishchuk, Y.; Papageorgiu, K.; Parenti, A.; Paul, E.; Pawlak, J. M.; Pawlik, B.; Pelfer, P. G.; Pellegrino, A.; Perlanski, W.; Perrey, H.; Piotrzkowski, K.; Plucinski, P.; Pokrovskiy, N. S.; Polini, A.; Proskuryakov, A. S.; Przybycie?, M.; Raval, A.; Reeder, D. D.; Reisert, B.; Ren, Z.; Repond, J.; Ri, Y. D.; Robertson, A.; Roloff, P.; Ron, E.; Rubinsky, I.; Ruspa, M.; Sacchi, R.; Salii, A.; Samson, U.; Sartorelli, G.; Savin, A. A.; Saxon, D. H.; Schioppa, M.; Schlenstedt, S.; Schleper, P.; Schmidke, W. B.; Schneekloth, U.; Schönberg, V.; Schörner-Sadenius, T.; Schwartz, J.; Sciulli, F.; Shcheglova, L. M.; Shehzadi, R.; Shimizu, S.; Singh, I.; Skillicorn, I. O.; S?omi?ski, W.; Smith, W. H.; Sola, V.; Solano, A.; Son, D.; Sosnovtsev, V.; Spiridonov, A.; Stadie, H.; Stanco, L.; Stern, A.; Stewart, T. P.; Stifutkin, A.; Stopa, P.; Suchkov, S.; Susinno, G.; Suszycki, L.; Sztuk-Dambietz, J.; Szuba, D.; Szuba, J.; Tapper, A. D.; Tassi, E.; Terrón, J.; Theedt, T.; Tiecke, H.; Tokushuku, K.; Tomalak, O.; Tomaszewska, J.; Tsurugai, T.; Turcato, M.; Tymieniecka, T.; Uribe-Estrada, C.; Vázquez, M.; Verbytskyi, A.; Viazlo, O.; Vlasov, N. N.; Volynets, O.; Walczak, R.; Wan Abdullah, W. A. T.; Whitmore, J. J.; Whyte, J.; Wiggers, L.; Wing, M.; Wlasenko, M.; Wolf, G.; Wolfe, H.; Wrona, K.; Yagües-Molina, A. G.; Yamada, S.; Yamazaki, Y.; Yoshida, R.; Youngman, C.; ?arnecki, A. F.; Zawiejski, L.; Zenaiev, O.; Zeuner, W.; Zhautykov, B. O.; Zhmak, N.; Zhou, C.; Zichichi, A.; Zolko, M.; Zotkin, D. S.; Zulkapli, Z.

2011-02-01

234

Double Parton Scattering in Associate Higgs Boson Production with Bottom Quarks at Hadron Colliders  

Microsoft Academic Search

Higgs boson production in association with bottom quarks, is one of the most\\u000aimportant discovery channels for Higgs particles in the Standard Model (SM) and\\u000aits supersymmetric extension at the LHC pp collider . The theoretical\\u000aprediction of the corresponding cross section has been improved by including\\u000athe complete next-to-leading order QCD corrections. We review the status\\u000aresults for the

M. Y. Hussein

2007-01-01

235

Production and characterization of activated carbon prepared from safflower seed cake biochar and its ability to absorb reactive dyestuff  

NASA Astrophysics Data System (ADS)

The use of activated carbon obtained from biochar for the removal of reactive dyestuff from aqueous solutions at various contact times, pHs and temperatures was investigated. The biochar was chemically modified with potassium hydroxide. The surface area and micropore volume of activated carbon was 1277 m2/g and 0.4952 cm3/g, respectively. The surface characterization of both biochar and activated carbon was undertaken using by Fourier transform infrared spectroscopy and scanning electron microscopy. The experimental data indicated that the adsorption isotherms are well described by the Dubinin-Radushkevich (DR) isotherm equation. The adsorption kinetics of reactive dyestuff obeys the pseudo second-order kinetic model. The thermodynamic parameters such as ?G?, ?H? and ?S? were calculated to estimate the nature of adsorption. The activation energy of the system was calculated as 1.12 kJ/mol. According to these results, prepared activated carbon could be used as a low-cost adsorbent to compare with the commercial activated carbon for the removal reactive dyestuff from wastewater.

Ang?n, Dilek; Köse, T. Ennil; Selengil, U?ur

2013-09-01

236

Flow cytometric assessment of morphology, viability, and production of reactive oxygen species of Crassostrea gigas oocytes. Application to Toxic dinoflagellate (Alexandrium minutum) exposure.  

PubMed

The Pacific oyster Crassostrea gigas accounts for a large part of shellfish aquaculture production worldwide. Aspects of morphological and functional characteristics of oyster oocytes remain poorly documented, and traditional techniques, such as microscopic observations of shape or fertilization rate, are time and space consuming. The purpose of this study was to assess for the first time viability and reactive oxygen species (ROS) production of Pacific oyster oocytes using flow cytometry (FCM) and to apply this method to determine oocyte responses to in vitro exposure to the toxic dinoflagellate Alexandrium minutum. A culture of A. minutum caused a significant increase in oocyte ROS production, which gradually increased with the age of the culture, but viability was not affected. Effect of the supernatant of the same A. minutum culture did not cause any significant modifications of oocyte morphology, viability, or ROS level. This study confirmed that some oocyte cellular characteristics can be assessed using FCM techniques. © 2014 International Society for Advancement of Cytometry. PMID:25327519

Le Goïc, Nelly; Hégaret, Hélène; Boulais, Myrina; Béguel, Jean-Philippe; Lambert, Christophe; Fabioux, Caroline; Soudant, Philippe

2014-12-01

237

Enhancement by Tumor Necrosis Factor Alpha of Dengue Virus-Induced Endothelial Cell Production of Reactive Nitrogen and Oxygen Species Is Key to Hemorrhage Development?  

PubMed Central

Hemorrhage is a severe manifestation of dengue disease. Virus strain and host immune response have been implicated as the risk factors for hemorrhage development. To delineate the complex interplay between the virus and the host, we established a dengue hemorrhage model in immune-competent mice. Mice inoculated intradermally with dengue virus develop hemorrhage within 3 days. In the present study, we showed by the presence of NS1 antigen and viral nuclei acid that dengue virus actively infects the endothelium at 12 h and 24 h after inoculation. Temporal studies showed that beginning at day 2, there was macrophage infiltration into the vicinity of the endothelium, increased tumor necrosis factor alpha (TNF-?) production, and endothelial cell apoptosis in the tissues. In the meantime, endothelial cells in the hemorrhage tissues expressed inducible nitric oxide synthase (iNOS) and nitrotyrosine. In vitro studies showed that primary mouse and human endothelial cells were productively infected by dengue virus. Infection by dengue virus induced endothelial cell production of reactive nitrogen and oxygen species and apoptotic cell death, which was greatly enhanced by TNF-?. NG-Nitro-l-arginine methyl ester and N-acetyl cysteine reversed the effects of dengue virus and TNF-? on endothelial cells. Importantly, hemorrhage development and the severity of hemorrhage were greatly reduced in mice lacking iNOS or p47phox or treatment with oxidase inhibitor, pointing to the critical roles of reactive nitrogen and oxygen species in dengue hemorrhage. PMID:18842737

Yen, Yu-Ting; Chen, Hseun-Chin; Lin, Yang-Ding; Shieh, Chi-Chang; Wu-Hsieh, Betty A.

2008-01-01

238

Three-jet production in diffractive deep inelastic scattering at HERA  

Microsoft Academic Search

Three-jet production in the reaction ep?eXp has been studied with the ZEUS detector at HERA using an integrated luminosity of 42.74 pb?1.The data were measured in the kinematic region 5

S. Bhadra; C. D. Catterall; W. R. Frisken; M. Khakzad; S. Magill; B. Musgrave; A. Pellegrino; J. Repond; R. Yoshida; M. C. K. Mattingly; P. Antonioli; G. Bari; M. Basile; L. Bellagamba; D. Boscherini; A. Bruni; G. Bruni; G. Cara Romeo; L. Cifarelli; F. Cindolo; A. Contin; M. Corradi; S. De Pasquale; P. Giusti; G. Iacobucci; G. Levi; A. Margotti; T. Massam; R. Nania; F. Palmonari; A. Pesci; G. Sartorelli; A. Zichichi; G. Aghuzumtsyan; I. Brock; S. Goers; H. Hartmann; E. Hilger; P. Irrgang; H.-P. Jakob; A. Kappes; U. F. Katz; R. Kerger; O. Kind; E. Paul; J. Rautenberg; H. Schnurbusch; A. Stifutkin; J. Tandler; K. C. Voss; A. Weber; H. Wieber; D. S. Bailey; N. H. Brook; J. E. Cole; B. Foster; G. P. Heath; H. F. Heath; S. Robins; E. Rodrigues; J. Scott; R. J. Tapper; M. Wing; M. Capua; A. Mastroberardino; M. Schioppa; G. Susinno; H. Y. Jeoung; J. Y. Kim; J. H. Lee; I. T. Lim; K. J. Ma; M. Y. Pac; A. Caldwell; M. Helbich; W. Liu; X. Liu; B. Mellado; S. Paganis; S. Sampson; W. B. Schmidke; F. Sciulli; J. Chwastowski; A. Eskreys; J. Figiel; K. Klimek; K. Olkiewicz; M. B. Przybycien; P. Stopa; L. Zawiejski; B. Bednarek; K. Jelen; D. Kisielewska; A. M. Kowal; M. Kowal; T. Kowalski; B. Mindur; E. Rulikowska-Zarebska; L. Suszycki; D. Szuba; A. Kotanski; L. A. T. Bauerdick; U. Behrens; K. Borras; V. Chiochia; J. Crittenden; D. Dannheim; K. Desler; G. Drews; A. Fox-Murphy; U. Fricke; A. Geiser; F. Goebel; P. Göttlicher; R. Graciani; T. Haas; W. Hain; G. F. Hartner; K. Hebbel; S. Hillert; W. Koch; U. Kötz; H. Kowalski; H. Labes; B. Löhr; R. Mankel; J. Martens; M. Martínez; M. Milite; M. Moritz; D. Notz; M. C. Petrucci; A. Polini; U. Schneekloth; F. Selonke; S. Stonjek; G. Wolf; U. Wollmer; J. J. Whitmore; R. Wichmann; C. Youngman; W. Zeuner; C. Coldewey; A. Lopez-Duran Viani; A. Meyer; S. Schlenstedt; G. Barbagli; E. Gallo; P. G. Pelfer; A. Bamberger; A. Benen; N. Coppola; P. Markun; H. Raach; S. Wölfle; M. Bell; P. J. Bussey; A. T. Doyle; C. Glasman; S. W. Lee; A. Lupi; G. J. McCance; D. H. Saxon; I. O. Skillicorn; B. Bodmann; N. Gendner; U. Holm; H. Salehi; K. Wick; A. Yildirim; A. Ziegler; T. Carli; A. Garfagnini; I. Gialas; E. Lohrmann; C. Foudas; R. Gonçalo; K. R. Long; F. Metlica; D. B. Miller; A. D. Tapper; R. Walker; P. Cloth; D. Filges; M. Kuze; K. Nagano; K. Tokushuku; S. Yamada; Y. Yamazaki; A. N. Barakbaev; E. G. Boos; N. S. Pokrovskiy; B. O. Zhautykov; S. H. Ahn; S. B. Lee; S. K. Park; H. Lim; D. Son; F. Barreiro; G. García; O. González; L. Labarga; J. del Peso; I. Redondo; J. Terrón; M. Vázquez; M. Barbi; A. Bertolin; F. Corriveau; A. Ochs; S. Padhi; D. G. Stairs; T. Tsurugai; A. Antonov; V. Bashkirov; P. Danilov; B. A. Dolgoshein; D. Gladkov; V. Sosnovtsev; S. Suchkov; R. K. Dementiev; P. F. Ermolov; Y. A. Golubkov; I. I. Katkov; L. A. Khein; N. A. Korotkova; I. A. Korzhavina; V. A. Kuzmin; B. B. Levchenko; O. Y. Lukina; A. S. Proskuryakov; L. M. Shcheglova; A. N. Solomin; N. N. Vlasov; S. A. Zotkin; C. Bokel; J. Engelen; S. Grijpink; E. Maddox; E. Koffeman; P. Kooijman; S. Schagen; E. Tassi; H. Tiecke; N. Tuning; J. J. Velthuis; L. Wiggers; E. de Wolf; N. Brümmer; B. Bylsma; L. S. Durkin; J. Gilmore; C. M. Ginsburg; C. L. Kim; T. Y. Ling; S. Boogert; A. M. Cooper-Sarkar; R. C. E. Devenish; J. Ferrando; J. Große-Knetter; T. Matsushita; M. Rigby; O. Ruske; M. R. Sutton; R. Walczak; R. Brugnera; R. Carlin; F. Dal Corso; S. Dusini; S. Limentani; A. Longhin; A. Parenti; M. Posocco; L. Stanco; M. Turcato; L. Adamczyk; L. Iannotti; B. Y. Oh; P. R. B. Saull; W. S. Toothacker; Y. Iga; G. D'Agostini; G. Marini; A. Nigro; C. Cormack; J. C. Hart; N. A. McCubbin; D. Epperson; C. Heusch; H. F.-W. Sadrozinski; A. Seiden; D. C. Williams; I. H. Park; N. Pavel; H. Abramowicz; S. Dagan; A. Gabareen; S. Kananov; A. Kreisel; A. Levy; T. Abe; T. Fusayasu; T. Kohno; K. Umemori; T. Yamashita; R. Hamatsu; T. Hirose; M. Inuzuka; S. Kitamura; K. Matsuzawa; T. Nishimura; M. Arneodo; N. Cartiglia; R. Cirio; M. Costa; M. I. Ferrero; S. Maselli; V. Monaco; C. Peroni; M. Ruspa; R. Sacchi; A. Solano; A. Staiano; D. C. Bailey; C.-P. Fagerstroem; R. Galea; T. Koop; G. M. Levman; J. F. Martin; A. Mirea; A. Sabetfakhri; J. M. Butterworth; C. Gwenlan; R. Hall-Wilton; M. E. Hayes; E. A. Heaphy; T. W. Jones; M. S. Lightwood; B. J. West; J. Ciborowski; R. Ciesielski; G. Grzelak; R. J. Nowak; J. M. Pawlak; B. Smalska; T. Tymieniecka; J. Ukleja; J. A. Zakrzewski; A. F. arnecki; M. Adamus; P. Plucinski; J. Sztuk; O. Deppe; Y. Eisenberg; L. K. Gladilin; D. Hochman; U. Karshon; J. Breitweg; D. Chapin; R. Cross; D. Kçira; S. Lammers; D. D. Reeder; A. A. Savin; W. H. Smith; A. Deshpande; S. Dhawan; V. W. Hughes; P. B. Straub; S. Menary

2001-01-01

239

Production of collimated positronium by positron scattering from CO2, N2 and Xe  

NASA Astrophysics Data System (ADS)

The efficiency for collimated positronium production by charge-exchange in positron collisions with gaseous targets has been investigated in the range 20-396 eV. At 250 and 396 eV, CO2 has been found to be approximately twice as efficient as N2, the previous best neutralising gas at high energies. The efficiency from Xe, whilst lower at low energies, becomes comparable to that from H2 at around 100-120 eV; at ˜250 eV, it is an order of magnitude lower.

Shipman, M.; Brawley, S.; Leslie, D. E.; Armitage, S.; Laricchia, G.

2012-04-01

240

Measurements of D0 production and of decay branching fractions in neutrino nucleon scattering  

NASA Astrophysics Data System (ADS)

During the years 1994 1997, the emulsion target of the CHORUS detector was exposed to the wide-band neutrino beam of the CERN SPS of 27 GeV average neutrino energy. In total about 100?000 charged-current neutrino interactions were located in the nuclear emulsion target and fully reconstructed. From this sample of events which was based on the data acquired by new automatic scanning systems, 1048 charged-current interactions with a D0 in the final state were selected by a pattern recognition program and confirmed as neutral-particle decays through visual inspection. The ratio of decay branching fractions of the D0 into four charged particles to two charged particles was measured to be B(D0?V4)/B(D0?V2)=0.207±0.016±0.004. The inclusive measurement of the observed production rate of the D0 with a decay into four charged prongs in combination with external measurements of this topological branching ratio was used to determine the total D0 production rate by neutrinos without additional assumption on the branching fractions. The value of this rate relative to the charged-current cross-section was found to be ?(D0)/?(CC)=0.0269±0.0018±0.0013. In addition, the same normalization method was used to deduce the inclusive topological decay rate into final states with neutral particles only. A value of 0.218±0.049±0.036 was found for this branching fraction. From an observed number of three charged six-prong events the branching ratio into six charged particles was determined to be (1.2-0.9+1.3±0.2)×10-3. A measurement of the energy dependence of the D0 production by neutrinos relative to the total charged-current cross-section is also reported. This measurement was used to deduce for mc, the effective charm-quark mass, a value of (1.42±0.08)GeV/c2.

CHORUS Collaboration; Önengüt, G.; van Dantzig, R.; de Jong, M.; Oldeman, R. G. C.; Güler, M.; Köse, U.; Tolun, P.; Catanesi, M. G.; Muciaccia, M. T.; Winter, K.; van de Vyver, B.; Vilain, P.; Wilquet, G.; Saitta, B.; di Capua, E.; Ogawa, S.; Shibuya, H.; Hristova, I. R.; Kayis-Topaksu, A.; Kawamura, T.; Kolev, D.; Meinhard, H.; Panman, J.; Rozanov, A.; Tsenov, R.; Uiterwijk, J. W. E.; Zucchelli, P.; Goldberg, J.; Chikawa, M.; Song, J. S.; Yoon, C. S.; Kodama, K.; Ushida, N.; Aoki, S.; Hara, T.; Delbar, T.; Favart, D.; Grégoire, G.; Kalinin, S.; Makhlioueva, I.; Artamonov, A.; Gorbunov, P.; Khovansky, V.; Shamanov, V.; Tsukerman, I.; Bruski, N.; Frekers, D.; Hoshino, K.; Kawada, J.; Komatsu, M.; Miyanishi, M.; Nakamura, M.; Nakano, T.; Narita, K.; Niu, K.; Niwa, K.; Nonaka, N.; Sato, O.; Toshito, T.; Buontempo, S.; Cocco, A. G.; D'Ambrosio, N.; de Lellis, G.; de Rosa, G.; di Capua, F.; Fiorillo, G.; Marotta, A.; Messina, M.; Migliozzi, P.; Scotto Lavina, L.; Sorrentino, M.; Strolin, P.; Tioukov, V.; Okusawa, T.; Dore, U.; Loverre, P. F.; Ludovici, L.; Rosa, G.; Santacesaria, R.; Satta, A.; Spada, F. R.; Barbuto, E.; Bozza, C.; Grella, G.; Romano, G.; Sirignano, C.; Sorrentino, S.; Sato, Y.; Tezuka, I.

2005-05-01

241

Production and characterization of thermoplastic cassava starch, functionalized poly(lactic acid), and their reactive compatibilized blends  

NASA Astrophysics Data System (ADS)

Cassava starch was blended with glycerol using a co-rotating twin-screw extruder (TSE). Thermoplastic cassava starch (TPCS) at a ratio of 70/30 by weight of cassava/glycerol was selected and further blended with other polymers. TPCS sheets made from compression molding had low tensile strength (0.45 +/- 0.05 MPa) and Young's modulus (1.24 +/- 0.58 MPa), but moderate elongation at break (83.0 +/- 0.18.6%), medium level of oxygen permeability, and high water vapor permeability with a very high rate of water absorption. TPCS was blended with poly(lactic acid) (PLA) at various ratios by using a TSE. The blend resins exhibited good properties such as increased thermal stability (Tmax) and crystallinity of PLA, and improved water sensitivity and processability of TPCS. PLA and TPCS exhibited a high interfacial tension between the two phases of 7.9 mJ·m -2, indicating the formation of an incompatible, immiscible blend. SEM micrographs showed a non-homogeneous distribution of TPCS droplets in the PLA continuous phase. TEM micrographs of the blend films made by cast-film extrusion showed coalescence of the TPCS droplets in the PLA continuous phase of the blend, indicating that the compatibility between the polymer pair needs to be improved. A response surface methodology (RSM) design was used to analyze the effects of maleic anhydride (MA) and 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane (Luperox or L101) contents, and TSE screw speed on the degree of grafted MA and number average molecular weight (Mn) of functionalized PLA (PLA-g-MA), a reactive compatibilizer. PLA-g- MA made by reactive extrusion had an array of colors depending on the content of L101 and MA used. New FTIR peaks suggested that MA was grafted onto the PLA backbone and oligomeric MA may occur. Increasing L101 increased the degree of grafting and decreased Mn, but the Mn of the PLA-g-MA's produced with a high amount of L101 was stable during storage. MA exhibited an optimum concentration for maximizing the degree of grafted MA, and increasing MA content retarded the reduction of Mn during processing. However, the Mn of PLA-g-MA during storage decreased more rapidly with a high content of MA. TSE screw speed had an impact on the Mn with the maximum value predicted at 20 rpm. PLA-g-MA compounds differing in Mn and/or grafted MA content were used as reactive polymers with TPCS (to produce binary blends) and as reactive compatibilizers (to produce ternary blends of PLA/TPCS/PLA-g-MA) with TPCS content of 30 wt% using a TSE. As a result of maleation, PLA-g-MA had a higher grafted MA content with a lower Mn, and higher PI. The interaction of anhydride groups from PLA-g-MA and hydroxyl groups from TPCS was found by FTIR. The reactive binary blends exhibited a change in thermal stability, decrease of Tcc, the presence of double melting peaks, and an increase of the Tgs of glycerol and starch. The higher the grafted MA content and/or the higher Mn of the PLA- g-MA used, the better were the distribution and smaller the TPCS domains obtained in the blends. The highest elongation at break was achieved when 30 wt% TPCS was blended with 70 wt% of PLA having 0.1 wt% of grafted MA and Mn of PLA-g-MA with a 45 kDa. Finally, the optimum PLA-g-MA was determined by using the results from PLA-g-MA RSM design and the reactive blending.

Detyothin, Sukeewan

242

Bupivacaine Induces Reactive Oxygen Species Production via Activation of the AMP-Activated Protein Kinase-Dependent Pathway  

Microsoft Academic Search

Aims: It was our aim to investigate whether AMP-activated protein kinase (AMPK) mediates the considerable increase in reactive oxygen species (ROS) and cell apoptosis induced by bupivacaine in the human neuroblastoma cell line SH-SY5Y. Methods: The recombinant plasmids pGPU6\\/GFP\\/Neo-shRNA AMPK?2 and pEGFP-N1-AMPK?2 were constructed and transfected into the SH-SY5Y cell line. The expression of AMPK?2 was determined by RT-PCR and

Jun Lu; Shi Yuan Xu; Qing Guo Zhang; Hong Yi Lei

2011-01-01

243

Detecting reactivity.  

PubMed

By definition, ecological systems at a stable equilibrium eventually return to the equilibrium point following a small perturbation. In the short term, however, perturbations can grow. Equilibria that exhibit transient growth following perturbation are said to be reactive. In this report, we present a statistical method for detecting reactivity from multivariate time series. The test is simple and computationally tractable, and it can be applied to short time series. Its main limitation is that it is based on a model of population dynamics that is linear on a logarithmic scale. Our results suggest that the test is robust when the dynamics are nonlinear on the log scale but that it may incorrectly classify an equilibrium as reactive when the reactivity is close to zero. PMID:19886478

Neubert, Michael G; Caswell, Hal; Solow, Andrew R

2009-10-01

244

TCDD decreases ATP levels and increases reactive oxygen production through changes in mitochondrial F F{sub 1}-ATP synthase and ubiquinone  

SciTech Connect

Mitochondria generate ATP and participate in signal transduction and cellular pathology and/or cell death. TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) decreases hepatic ATP levels and generates mitochondrial oxidative DNA damage, which is exacerbated by increasing mitochondrial glutathione redox state and by inner membrane hyperpolarization. This study identifies mitochondrial targets of TCDD that initiate and sustain reactive oxygen production and decreased ATP levels. One week after treating mice with TCDD, liver ubiquinone (Q) levels were significantly decreased, while rates of succinoxidase and Q-cytochrome c oxidoreductase activities were increased. However, the expected increase in Q reduction state following TCDD treatment did not occur; instead, Q was more oxidized. These results could be explained by an ATP synthase defect, a premise supported by the unusual finding that TCDD lowers ATP/O ratios without concomitant changes in respiratory control ratios. Such results suggest either a futile cycle in ATP synthesis, or hydrolysis of newly synthesized ATP prior to release. The TCDD-mediated decrease in Q, concomitant with an increase in respiration, increases complex 3 redox cycling. This acts in concert with glutathione to increase membrane potential and reactive oxygen production. The proposed defect in ATP synthase explains both the greater respiratory rates and the lower tissue ATP levels.

Shertzer, Howard G. [Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati Medical Center, P.O. Box 670056 Cincinnati, OH 45267-0056 (United States)]. E-mail: shertzhg@ucmail.uc.edu; Genter, Mary Beth [Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati Medical Center, P.O. Box 670056 Cincinnati, OH 45267-0056 (United States); Shen, Dongxiao [Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati Medical Center, P.O. Box 670056 Cincinnati, OH 45267-0056 (United States); Nebert, Daniel W. [Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati Medical Center, P.O. Box 670056 Cincinnati, OH 45267-0056 (United States); Chen, Ying [Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati Medical Center, P.O. Box 670056 Cincinnati, OH 45267-0056 (United States); Dalton, Timothy P. [Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati Medical Center, P.O. Box 670056 Cincinnati, OH 45267-0056 (United States)

2006-12-15

245

Effect of olive mill wastewater phenol compounds on reactive carbonyl species and maillard reaction end-products in ultrahigh-temperature-treated milk.  

PubMed

Thermal processing and Maillard reaction (MR) affect the nutritional and sensorial qualities of milk. In this paper an olive mill wastewater phenolic powder (OMW) was tested as a functional ingredient for inhibiting MR development in ultrahigh-temperature (UHT)-treated milk. OMW was added to milk at 0.1 and 0.05% w/v before UHT treatment, and the concentration of MR products was monitored to verify the effect of OMW phenols in controlling the MR. Results revealed that OMW is able to trap the reactive carbonyl species such as hydroxycarbonyls and dicarbonyls, which in turn led to the increase of Maillard-derived off-flavor development. The effect of OMW on the formation of Amadori products and N-?-(carboxymethyl)-lysine (CML) showed that oxidative cleavage, C2-C6 cyclization, and the consequent reactive carbonyl species formation were also inhibited by OMW. Data indicated that OMW is a functional ingredient able to control the MR and to improve the nutritional and sensorial attributes of milk. PMID:25280240

Troise, Antonio Dario; Fiore, Alberto; Colantuono, Antonio; Kokkinidou, Smaro; Peterson, Devin G; Fogliano, Vincenzo

2014-10-15

246

The histone deacetylase inhibitor and chemotherapeutic agent suberoylanilide hydroxamic acid (SAHA) induces a cell-death pathway characterized by cleavage of Bid and production of reactive oxygen species.  

PubMed

Many chemotherapeutic agents induce mitochondrial-membrane disruption to initiate apoptosis. However, the upstream events leading to drug-induced mitochondrial perturbation have remained poorly defined. We have used a variety of physiological and pharmacological inhibitors of distinct apoptotic pathways to analyze the manner by which suberoylanilide hydroxamic acid (SAHA), a chemotherapeutic agent and histone deacetylase inhibitor, induces cell death. We demonstrate that SAHA initiates cell death by inducing mitochondria-mediated death pathways characterized by cytochrome c release and the production of reactive oxygen species, and does not require the activation of key caspases such as caspase-8 or -3. We provide evidence that mitochondrial disruption is achieved by means of the cleavage of the BH3-only proapoptotic Bcl-2 family member Bid. SAHA-induced Bid cleavage was not blocked by caspase inhibitors or the overexpression of Bcl-2 but did require the transcriptional regulatory activity of SAHA. These data provide evidence of a mechanism of cell death mediated by transcriptional events that result in the cleavage of Bid, disruption of the mitochondrial membrane, and production of reactive oxygen species to induce cell death. PMID:11535817

Ruefli, A A; Ausserlechner, M J; Bernhard, D; Sutton, V R; Tainton, K M; Kofler, R; Smyth, M J; Johnstone, R W

2001-09-11

247

Photosensitization of CdSe/ZnS QDs and reliability of assays for reactive oxygen species production.  

SciTech Connect

CdSe/ZnS quantum dots (QDs) conjugated to biomolecules that can act as electron donors are said to be 'photosensitized': that is, they are able to oxidize or reduce molecules whose redox potential lies inside their band edges, in particular molecular oxygen and water. This leads to the formation of reactive oxygen species (ROS) and phototoxicity. In this work, we quantify the generation of different forms of ROS from as-synthesized QDs in toluene; water-solubilized, unconjugated QDs; QDs conjugated to the neurotransmitter dopamine; and dopamine alone. Results of indirect fluorescent ROS assays, both in solution and inside cells, are compared with those of spin-trap electron paramagentic resonance spectroscopy (EPR). The effect of these particles on the metabolism of mammalian cells is shown to be dependent upon light exposure and proportional to the amount of ROS generated.

Cooper, D. R.; Dimitrijevic, N. M.; Nadeau, J. L.; McGill Univ.

2010-01-01

248

Single photon production {nu}{sub l}N{yields}{nu}{sub l}N{gamma} in neutrino-nucleon scattering  

SciTech Connect

The quasielastic charged current (CCQE) {nu}{sub e}n{yields}e{sup -}p scattering is the dominant mechanism to detect appearance of a {nu}{sub e} in an almost {nu}{sub {mu}} flux at the 1 GeV scale. Actual experiments show a precision below 1% and between less known background contributions, but necessary to constraint the event excess, we have the radiative corrections. A consistent model recently developed for the simultaneous description of elastic and radiative {pi}N scattering, pion-photoproduction and single pion production processes, both for charged and neutral current neutrino-nucleon scattering, is extended for the evaluation of the radiative {nu}{sub l}N{yields}{nu}{sub l}N{gamma} cross section. Our results are similar to a previous (but inconsistent) theoretical evaluation in the low energy region, and show an increment in the upper region where the {Delta} resonance becomes relevant.

Barbero, C.; Mariano, A. [Departamento de Fisica, Universidad Nacional de La Plata, C. C. 67, 1900 La Plata (Argentina)

2013-05-06

249

Sestrin2 decreases renal oxidative stress, lowers blood pressure, and mediates dopamine D2 receptor-induced inhibition of reactive oxygen species production.  

PubMed

The dopamine D2 receptor (D2R) decreases renal reactive oxygen species (ROS) production and regulates blood pressure, in part, via positive regulation of paraoxonase 2. Sestrin2, a highly conserved antioxidant protein, regulates intracellular ROS level by regenerating hyperoxidized peroxiredoxins. We hypothesized that sestrin2 may be involved in preventing excessive renal ROS production and thus contribute to the maintenance of normal blood pressure. Moreover, the D2R may decrease ROS production, in part, through the regulation of sestrin2. Renal sestrin2 expression was lower (-62±13%) in D2R(-/-) than in D2R(+/+) mice. Silencing D2R in human renal proximal tubule cells decreased sestrin2 expression (-53±3%) and increased hyperoxidized peroxiredoxins (2.9-fold). Stimulation of D2R in renal proximal tubule cells increased sestrin2 expression (1.6-fold), decreased hyperoxidized peroxiredoxins (-61±3%), and reduced ROS production (-31±4%). Silencing sestrin2 in renal proximal tubule cells increased hyperoxidized peroxiredoxins (2.1-fold) and ROS production (1.3-fold). Silencing sestrin2 also abolished D2R-induced decrease in peroxiredoxin hyperoxidation and partially prevented the inhibitory effect of D2R stimulation on ROS production. Silencing paraoxonase 2 increased sestrin2 ubiquitinylation (2.8-fold), decreased sestrin2 expression (-30±3%), and increased ROS production (1.3-fold), peroxiredoxin hyperoxidation (2.9-fold), and lipid peroxidation (2.3-fold), and blocked the increase in sestrin2 that occurs with D2R stimulation. In vivo renal selective silencing of sestrin2 by the renal subcapsular infusion of sestrin2 small interfering RNA (3 ?g/day; 7 days) in mice increased renal oxidative stress (1.3-fold) and blood pressure. These results suggest that the D2R, via paraoxonase 2 and sestrin2, keeps normal renal redox balance, which contributes to the maintenance of normal blood pressure. PMID:25024286

Yang, Yu; Cuevas, Santiago; Yang, Sufei; Villar, Van Anthony; Escano, Crisanto; Asico, Laureano; Yu, Peiying; Jiang, Xiaoliang; Weinman, Edward J; Armando, Ines; Jose, Pedro A

2014-10-01

250

Up-regulation of avian uncoupling protein in cold-acclimated and hyperthyroid ducklings prevents reactive oxygen species production by skeletal muscle mitochondria  

PubMed Central

Background Although identified in several bird species, the biological role of the avian homolog of mammalian uncoupling proteins (avUCP) remains extensively debated. In the present study, the functional properties of isolated mitochondria were examined in physiological or pharmacological situations that induce large changes in avUCP expression in duckling skeletal muscle. Results The abundance of avUCP mRNA, as detected by RT-PCR in gastrocnemius muscle but not in the liver, was markedly increased by cold acclimation (CA) or pharmacological hyperthyroidism but was down-regulated by hypothyroidism. Activators of UCPs, such as superoxide with low doses of fatty acids, stimulated a GDP-sensitive proton conductance across the inner membrane of muscle mitochondria from CA or hyperthyroid ducklings. The stimulation was much weaker in controls and not observed in hypothyroid ducklings or in any liver mitochondrial preparations. The production of endogenous mitochondrial reactive oxygen species (ROS) was much lower in muscle mitochondria from CA and hyperthyroid ducklings than in the control or hypothyroid groups. The addition of GDP markedly increased the mitochondrial ROS production of CA or hyperthyroid birds up to, or above, the level of control or hypothyroid ducklings. Differences in ROS production among groups could not be attributed to changes in antioxidant enzyme activities (superoxide dismutase or glutathione peroxidase). Conclusion This work provides the first functional in vitro evidence that avian UCP regulates mitochondrial ROS production in situations of enhanced metabolic activity. PMID:20426850

2010-01-01

251

Relationships between human vitality and mitochondrial respiratory parameters, reactive oxygen species production and dNTP levels in peripheral blood mononuclear cells  

PubMed Central

Low vitality (a component of fatigue) in middle-aged and older adults is an important complaint often identified as a symptom of a disease state or side effect of a treatment. No studies to date have investigated the potential link between dysfunctional mitochondrial ATP production and low vitality. Therefore, we measured a number of cellular parameters related to mitochondrial activity in peripheral blood mononuclear cells (PBMCs) isolated from middle-aged men, and tested for association with vitality. These parameters estimate mitochondrial respiration, reactive oxygen species (ROS) production, and deoxyribonucleotide (dNTP) balance in PBMCs. The population was drawn from the Metropolit cohort of men born in 1953. Vitality level was estimated from the Medical Outcomes Study Short Form 36 (SF-36) vitality scale. We found that vitality score had no association with any of the mitochondrial respiration parameters. However, vitality score was inversely associated with cellular ROS production and cellular deoxythymidine triphosphate (dTTP) levels and positively associated with deoxycytidine triphosphate (dCTP) levels. We conclude that self-reported persistent low vitality is not associated with specific aspects of mitochondrial oxidative phosphorylation capacity in PBMCs, but may have other underlying cellular dysfunctions that contribute to dNTP imbalance and altered ROS production. PMID:24304678

Gram, Martin; Desler, Claus; Bendix, Laila; Budtz-J?rgensen, Esben; Molbo, Drude; Croteau, Deborah L.; Osler, Merete; Stevnsner, Tinna; Rasmussen, Lene Juel; Dela, Flemming; Avlund, Kirsten; Bohr, Vilhelm A.

2013-01-01

252

Endogenous abscisic acid is involved in methyl jasmonate-induced reactive oxygen species and nitric oxide production but not in cytosolic alkalization in Arabidopsis guard cells.  

PubMed

We recently demonstrated that endogenous abscisic acid (ABA) is involved in methyl jasmonate (MeJA)-induced stomatal closure in Arabidopsis thaliana. In this study, we investigated whether endogenous ABA is involved in MeJA-induced reactive oxygen species (ROS) and nitric oxide (NO) production and cytosolic alkalization in guard cells using an ABA-deficient Arabidopsis mutant, aba2-2, and an inhibitor of ABA biosynthesis, fluridon (FLU). The aba2-2 mutation impaired MeJA-induced ROS and NO production. FLU inhibited MeJA-induced ROS production in wild-type guard cells. Pretreatment with 0.1 ?M ABA, which does not induce stomatal closure in the wild type, complemented the insensitivity to MeJA of the aba2-2 mutant. However, MeJA induced cytosolic alkalization in both wild-type and aba2-2 guard cells. These results suggest that endogenous ABA is involved in MeJA-induced ROS and NO production but not in MeJA-induced cytosolic alkalization in Arabidopsis guard cells. PMID:23608742

Ye, Wenxiu; Hossain, Mohammad Anowar; Munemasa, Shintaro; Nakamura, Yoshimasa; Mori, Izumi C; Murata, Yoshiyuki

2013-09-01

253

Formation of ferrihydrite and associated iron corrosion products in permeable reactive barriers of zero-valent iron  

NASA Technical Reports Server (NTRS)

Ferrihydrite, which is known to form in the presence of oxygen and to be stabilized by the adsorption of Si, PO4 and SO4, is ubiquitous in the fine-grained fractions of permeable reactive barrier (PRB) samples from the U.S. Coast Guard Support Center (Elizabeth City, NC) and the Denver Federal Center (Lakewood, CO) studied by high-resolution transmission electron microscopy and selected area electron diffraction. The concurrent energy-dispersive X-ray data indicate a strong association between ferrihydrite and metals such as Si, Ca, and Cr. Magnetite, green rust 1, aragonite, calcite, mackinawite, greigite and lepidocrocite were also present, indicative of a geochemical environment that is temporally and spatially heterogeneous. Whereas magnetite, which is known to form due to anaerobic Fe0 corrosion, passivates the Fe0 surface, ferrihydrite precipitation occurs away from the immediate Fe0 surface, forming small (<0.1 microm) discrete clusters. Consequently, Fe0-PRBs may remain effective for a longer period of time in slightly oxidized groundwater systems where ferrihydrite formation occurs compared to oxygen-depleted systems where magnetite passivation occurs. The ubiquitous presence of ferrihydrite suggests that the use of Fe0-PRBs may be extended to applications that require contaminant adsorption rather than, or in addition to, redox-promoted contaminant degradation.

Furukawa, Yoko; Kim, Jin-Wook; Watkins, Janet; Wilkin, Richard T.

2002-01-01

254

Transient Influx of Nickel in Root Mitochondria Modulates Organic Acid and Reactive Oxygen Species Production in Nickel Hyperaccumulator Alyssum murale*  

PubMed Central

Mitochondria are important targets of metal toxicity and are also vital for maintaining metal homeostasis. Here, we examined the potential role of mitochondria in homeostasis of nickel in the roots of nickel hyperaccumulator plant Alyssum murale. We evaluated the biochemical basis of nickel tolerance by comparing the role of mitochondria in closely related nickel hyperaccumulator A. murale and non-accumulator Alyssum montanum. Evidence is presented for the rapid and transient influx of nickel in root mitochondria of nickel hyperaccumulator A. murale. In an early response to nickel treatment, substantial nickel influx was observed in mitochondria prior to sequestration in vacuoles in the roots of hyperaccumulator A. murale compared with non-accumulator A. montanum. In addition, the mitochondrial Krebs cycle was modulated to increase synthesis of malic acid and citric acid involvement in nickel hyperaccumulation. Furthermore, malic acid, which is reported to form a complex with nickel in hyperaccumulators, was also found to reduce the reactive oxygen species generation induced by nickel. We propose that the interaction of nickel with mitochondria is imperative in the early steps of nickel uptake in nickel hyperaccumulator plants. Initial uptake of nickel in roots results in biochemical responses in the root mitochondria indicating its vital role in homeostasis of nickel ions in hyperaccumulation. PMID:23322782

Agrawal, Bhavana; Czymmek, Kirk J.; Sparks, Donald L.; Bais, Harsh P.

2013-01-01

255

Honokiol induces caspase-independent paraptosis via reactive oxygen species production that is accompanied by apoptosis in leukemia cells.  

PubMed

Our previous report has shown that honokiol (HNK), a constituent of Magnolia officinalis, induces a novel form of non-apoptotic programmed cell death in human leukemia NB4 and K562 cells. In this study, we further explored the relationship between the cell death pathway and cytoplasmic vacuolization and studied the underlying mechanism of leukemia cell death mediated by honokiol. The results showed that low concentrations of honokiol activated an novel alternative cell death fitted the criteria of paraptosis, such as cytoplasmic vacuolization derived from endoplasmic reticulum swelling, lack of caspase activation, and lack of apoptotic morphology. Results further indicated that the cell death was time- and concentration-dependent. In addition, honokiol-induced paraptosis did not involve membrane blebbing, chromatin condensation and phosphatidylserine exposure at the outer of the plasma membrane. The mechanism of the cell death may be associated, at least in part, with the increased generation of reactive oxygen species. Further analysis showed that honokiol induces cell death predominantly via paraptosis and to a certain extent via apoptosis in NB4 cells, and predominantly via apoptosis and to a certain extent via paraptosis in K562 cells. These observations suggest that cell death occurs via more than one pathway in leukemia cells and targeting paraptosis may be an alternative and promising avenue for honokiol in leukemia therapy. PMID:23262230

Wang, Yao; Zhu, Xiuping; Yang, Zehong; Zhao, Xiaojun

2013-01-18

256

Genome-Wide Screening with Hydroxyurea Reveals a Link between Nonessential Ribosomal Proteins and Reactive Oxygen Species Production  

PubMed Central

We performed a screening of hydroxyurea (HU)-sensitive mutants using a single-gene-deletion mutant collection in Escherichia coli. HU inhibits ribonucleotide reductase (RNR), which leads to arrest of the replication fork. Surprisingly, the wild-type was less resistant to HU than the average for the Keio Collection. Respiration-defective mutants were significantly more resistant to HU, suggesting that the generation of reactive oxygen species (ROS) contributes to cell death. High-throughput screening revealed that 15 mutants were completely sensitive on plates containing 7.5 mM HU. Unexpectedly, translation-related mutants based on COG categorization were the most enriched, and three of them were deletion mutants of nonessential ribosomal proteins (L1, L32, and L36). We found that, in these mutants, an increased membrane stress response was provoked, resulting in increased ROS generation. The addition of OH radical scavenger thiourea rescued the HU sensitivity of these mutants, suggesting that ROS generation is the direct cause of cell death. Conversely, both the deletion of rpsF and the deletion of rimK, which encode S6 and S6 modification enzymes, respectively, showed an HU-resistant phenotype. These mutants increased the copy number of the p15A-based plasmid and exhibited reduced basal levels of SOS response. The data suggest that nonessential proteins indirectly affect the DNA-damaging process. PMID:23292777

Mori, Hirotada

2013-01-01

257

Reactive quenching of OH A 2?+ by O2 and CO: Experimental and nonadiabatic theoretical studies of H- and O-atom product channels  

NASA Astrophysics Data System (ADS)

The outcomes following collisional quenching of electronically excited OH A 2?+ by O2 and CO are examined in a combined experimental and theoretical study. The atomic products from reactive quenching are probed using two-photon laser-induced fluorescence to obtain H-atom Doppler profiles, O (3PJ) atom fine structure distributions, and the relative yields of these products with H2, O2, and CO collision partners. The corresponding H-atom translational energy distributions are extracted for the H + O3 and H + CO2 product channels, in the latter case revealing that most of the available energy is funneled into internal excitation of CO2. The experimental product branching ratios show that the O-atom producing pathways are the dominant outcomes of quenching: the OH A 2?+ + O2 --> O + HO2 channel accounts for 48(3)% of products and the OH A 2?+ + CO --> O + HCO channel yields 76(5)% of products. In addition, quenching of OH A 2?+ by O2 generates H + O3 products [12(3)%] and returns OH to its ground X 2? electronic state [40(1)% L. P. Dempsey, T. D. Sechler, C. Murray, and M. I. Lester, J. Phys. Chem. A 113, 6851 (2009)]. Quenching of OH A 2?+ by CO also yields H + CO2 reaction products [26(5)%] however, OH X 2? (v'' = 0,1) products from nonreactive quenching are not observed. Theoretical studies characterize the properties of energy minimized conical intersections in four regions of strong nonadiabatic coupling accessible from the OH A 2?+ + CO asymptote. Three of these regions have the O-side of OH pointing toward CO, which lead to atomic H and vibrationally excited CO2 products and/or nonreactive quenching. In the fourth region, energy minimized points are located on a seam of conical intersection from the OH A 2?+ + CO asymptote to an energy minimized crossing with an extended OH bond length and the H-side of OH pointing toward CO in a bent configuration. This region, exoergic with respect to the reaction asymptote, is likely to be the origin of the dominant O + HCO product channel.

Lehman, Julia H.; Lester, Marsha I.; Yarkony, David R.

2012-09-01

258

PROTEIN ADDUCTS OF ALDEHYDIC LIPID PEROXIDATION PRODUCTS: IDENTIFICATION AND CHARACTERIZATION OF PROTEIN ADDUCTS USING AN ALDEHYDE/KETO REACTIVE PROBE IN COMBINATION WITH MASS SPECTROMETRY  

PubMed Central

This chapter describes a mass spectrometry-based strategy that facilitates the unambiguous identification and characterization of proteins modified by lipid peroxidation-derived 2-alkenals. The approach employs a biotinylated hydroxyl amine derivative as an aldehyde/keto reactive probe in conjunction with selective enrichment and tandem mass spectrometric analysis. Methodological details are given for model studies involving a distinct protein and 4-hydroxy-2-nonenal (HNE). The method was also evaluated for an exposure study of a cell culture system with HNE that yielded the major protein targets of HNE in human monocytic THP-1 cells. The application of the approach to complex biological systems is demonstrated for the identification and characterization of endogenous protein targets of aldehydic lipid peroxidation products present in cardiac mitochondria. PMID:20513485

Maier, Claudia S.; Chavez, Juan; Wang, Jing; Wu, Jianyong

2014-01-01

259

Rayleigh Scattering.  

ERIC Educational Resources Information Center

The correct usage of such terminology as "Rayleigh scattering,""Rayleigh lines,""Raman lines," and "Tyndall scattering" is resolved during an historical excursion through the physics of light-scattering by gas molecules. (Author/JN)

Young, Andrew T.

1982-01-01

260

Structural Insights into 2,2'-Azino-Bis(3-Ethylbenzothiazoline-6-Sulfonic Acid) (ABTS)-Mediated Degradation of Reactive Blue 21 by Engineered Cyathus bulleri Laccase and Characterization of Degradation Products.  

PubMed

Advanced oxidation processes are currently used for the treatment of different reactive dyes which involve use of toxic catalysts. Peroxidases are reported to be effective on such dyes and require hydrogen peroxide and/or metal ions. Cyathus bulleri laccase, expressed in Pichia pastoris, catalyzes efficient degradation (78 to 85%) of reactive azo dyes (reactive black 5, reactive orange 16, and reactive red 198) in the presence of synthetic mediator ABTS [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)]. This laccase was engineered to degrade effectively reactive blue 21 (RB21), a phthalocyanine dye reported to be decolorized only by peroxidases. The 816-bp segment (toward the C terminus) of the lcc gene was subjected to random mutagenesis and enzyme variants (Lcc35, Lcc61, and Lcc62) were selected based on increased ABTS oxidizing ability. Around 78 to 95% decolorization of RB21 was observed with the ABTS-supplemented Lcc variants in 30 min. Analysis of the degradation products by mass spectrometry indicated the formation of several low-molecular-weight compounds. Mapping the mutations on the modeled structure implicated residues both near and far from the T1 Cu site that affected the catalytic efficiency of the mutant enzymes on ABTS and, in turn, the rate of oxidation of RB21. Several inactive clones were also mapped. The importance of geometry as well as electronic changes on the reactivity of laccases was indicated. PMID:25261507

Kenzom, T; Srivastava, P; Mishra, S

2014-12-15

261

Two-pion production in {alpha}p scattering at 1 GeV/nucleon in the energy region of the Roper resonance excitation  

SciTech Connect

Semiexclusive measurements of the two-pion-production p({alpha},{alpha}{sup '})p{pi}{pi} reaction have been carried out at an energy of E{sub {alpha}}=4.2 GeV at the Saturne-II (Saclay) accelerator with the SPES4-{pi} installation. This reaction was investigated by simultaneous registration of the scattered {alpha} particle and the secondary proton. The obtained results show that the two-pion production in inelastic {alpha}-particle scattering on the proton at the energy of the experiment proceeds mainly through excitation in the target proton of the Roper resonance and its decay with emission of two pions in the isospin I=0,S-wave state.

Alkhazov, G. D.; Kravtsov, A. V.; Mylnikov, V. A.; Orischin, E. M.; Prokofiev, A. N.; Razmyslovich, B. V.; Smirnov, I. B.; Tkach, I. I.; Volkov, S. S.; Zhdanov, A. A. [Petersburg Nuclear Physics Institute, Gatchina RU-188300 (Russian Federation); Augustyniak, W.; Zupranski, P. [Institute for Nuclear Studies, Warsaw PL-00681 (Poland); Boivin, M. [Laboratoire National Saturne, CNRS/IN2P3 and CEA/DSM, Gif-sur-Yvette Cedex F-91191 (France); Boyard, J.-L.; Farhi, L.; Hennino, T.; Jourdain, J.-C.; Kunne, R.; Ramstein, B.; Roy-Stephan, M. [Institut de Physique Nucleaire Orsay, CNRS/IN2P3, Orsay F-91400 (France)] (and others)

2008-08-15

262

Fully quantum state-resolved inelastic scattering of NO(X) + Kr: Differential cross sections and product rotational alignment  

NASA Astrophysics Data System (ADS)

Fully quantum state selected and resolved inelastic scattering of NO(X) by krypton has been investigated. Initial ?-doublet state selection is achieved using an inhomogeneous hexapole electric field. Differential cross sections and even-moment polarization dependent differential cross sections have been obtained at a collision energy of 514 cm-1 for both spin-orbit and parity conserving and changing collisions. Experimental results are compared with those obtained from quantum scattering calculations and are shown to be in very good agreement. Hard shell quantum scattering calculations are also performed to determine the effects of the different parts of the potential on the scattering dynamics. Comparisons are also made with the NO(X) + Ar system.

Brouard, M.; Chadwick, H.; Gordon, S. D. S.; Hornung, B.; Nichols, B.; K?os, J.; Aoiz, F. J.; Stolte, S.

2014-10-01

263

Double spin asymmetry AL?T? in charged pion production from deep inelastic scattering on a transversely polarized ³He target  

E-print Network

In this thesis I discuss the first measurement of the beam-target double-spin asymmetry ALT for charged pion electroproduction in deep inelastic electron scattering on a transversely polarized 3He target. These data were ...

Huang, Jin, Ph. D. Massachusetts Institute of Technology

2012-01-01

264

Atmospheric photochemical reactivity and ozone production at two sites in Hong Kong: Application of a Master Chemical Mechanism-photochemical box model  

NASA Astrophysics Data System (ADS)

photochemical box model incorporating the Master Chemical Mechanism (v3.2), constrained with a full suite of measurements, was developed to investigate the photochemical reactivity of volatile organic compounds at a semirural site (Mount Tai Mo Shan (TMS)) and an urban site (Tsuen Wan (TW)) in Hong Kong. The levels of ozone (O3) and its precursors, and the magnitudes of the reactivity of O3 precursors, revealed significant differences in the photochemistry at the two sites. Simulated peak hydroperoxyl radical (HO2) mixing ratios were similar at TW and TMS (p = 0.05), while the simulated hydroxyl radical (OH) mixing ratios were much higher at TW (p < 0.05), suggesting different cycling processes between OH and HO2 at the two sites. The higher OH at TW was due to high-NO mixing ratios, which shifted the HOx (OH + HO2) balance toward OH by the propagation of HO2 and alkyl peroxy radicals (RO2) with NO. HOx production was dominated by O3 photolysis at TMS, but at TW, both HCHO and O3 photolyses were found to be major contributors. By contrast, radical-radical reactions governed HOx radical losses at TMS, while at TW, the OH + NO2 reaction was found to dominate in the morning and the radical-radical reactions at noon. Overall, the conversion of NO to NO2 by HO2 dictated the O3 production at the two sites, while O3 destruction was dominated by the OH + NO2 reaction at TW, and at TMS, O3 photolysis and the O3 + HO2 reaction were the major mechanisms. The longer OH chain length at TMS indicated that more O3 was produced for each radical that was generated at this site.

Ling, Z. H.; Guo, H.; Lam, S. H. M.; Saunders, S. M.; Wang, T.

2014-09-01

265

A Positive-Weight Next-to-Leading-Order Monte Carlo Simulation of Deep Inelastic Scattering and Higgs Boson Production via Vector Boson Fusion in Herwig++  

E-print Network

The positive weight next-to-leading-order matching formalism (POWHEG) is applied to Deep Inelastic Scattering (DIS) and the related Higgs boson production via vector-boson fusion process in the Herwig++ Monte Carlo event generator. This scheme combines parton shower simulation and next-to-leading-order calculation in a consistent way which only produces positive weight events. The simulation contains a full implementation of the truncated shower required to correctly model soft emissions in an angular-ordered parton shower.

Luca D'Errico; Peter Richardson

2011-06-15

266

Measurement of nuclear transparencies from exclusive [rho][sup 0] meson production in muon-nucleus scattering at 470 GeV  

SciTech Connect

Nuclear transparencies measured in exclusive incoherent [rho][sup 0] meson production from hydrogen, deuterium, carbon, calcium, and lead in muon-nucleus scattering are reported. The data were obtained with the E665 spectrometer using the Fermilab Tevatron muon beam with a mean beam energy of 470 GeV. Increases in the nuclear transparencies are observed as the virtuality of the photon increases, in qualitative agreement with the expectations of color transparency.

Adams, M.R.; Aied, S.; Anthony, P.L.; Averill, D.A.; Baker, M.D.; Baller, B.R.; Banerjee, A.; Bhatti, A.A.; Bratzler, U.; Braun, H.M.; Breidung, H.; Busza, W.; Carroll, T.J.; Clark, H.L.; Conrad, J.M.; Davisson, R.; Derado, I.; Dhawan, S.K.; Dietrich, F.S.; Dougherty, W.; Dreyer, T.; Eckardt, V.; Ecker, U.; Erdmann, M.; Faller, F.; Fang, G.Y.; Figiel, J.; Finlay, R.W.; Gebauer, H.J.; Geesaman, D.F.; Griffioen, K.A.; Guo, R.S.; Haas, J.; Halliwell, C.; Hantke, D.; Hicks, K.H.; Hughes, V.W.; Jackson, H.E.; Jancso, G.; Jansen, D.M.; Jin, Z.; Kaufman, S.; Kennedy, R.D.; Kinney, E.R.; Kirk, T.; Kobrak, H.G.E.; Kotwal, A.V.; Kunori, S.; Lancaster, S.; Lord, J.J.; Lubatti, H.J.; McLeod, D.; Madden, P.; Magill, S.; Manz, A.; Melanson, H.; Michael, D.G.; Montgomery, H.E.; Morfin, J.G.; Nickerson, R.B.; O'Day, S.; Olkiewicz, K.; Osborne, L.; Otten, R.; Papavassiliou, V.; Pawlik, B.; Pipkin, F.M.; Potterveld, D.H.; Ramberg, E.J.; Roeser, A.; Ryan, J.J.; Salgado, C.W.; Salvarani, A.; Schellman, H.; (Fermilab E665 Collaboration)

1995-02-27

267

Enhanced pilot-scale fed-batch L-phenylalanine production with recombinant Escherichia coli by fully integrated reactive extraction  

Microsoft Academic Search

A fully integrated process for the microbial production and recovery of the aromatic amino acid L-phenylalanine is presented. Using a recombinant L-tyrosine (L-Tyr) auxotrophic Escherichia coli production strain, a fed-batch fermentation process was developed in a 20-l-scale bioreactor. Concentrations of glucose and L-Tyr were closed-loop-controlled in a fed-batch process. After achieving final L-phenylalanine (L-Phe) titres >30 g\\/l the process strategy

M. Gerigk; D. Maass; A. Kreutzer; G. Sprenger; J. Bongaerts; M. Wubbolts; R. Takors

2002-01-01

268

Production of reactive oxygen species and wound-induced resistance in Arabidopsis thaliana against Botrytis cinerea are preceded and depend on a burst of calcium  

PubMed Central

Background Wounded leaves of Arabidopsis thaliana produce reactive oxygen species (ROS) within minutes after wounding and become resistant to the pathogenic fungus Botrytis cinerea at a local level. This fast response of the plants to the wound is called wound-induced resistance (WIR). However the molecular mechanisms of this response and the signal cascade between the wound and ROS production are still largely unknown. Calcium is a conserved signal and it is involved in many abiotic stress responses in plants, furthermore, calcium pathways act very fast. Results The results of this study show that leaves treated with calcium channels inhibitors (verapamil) or calcium chelators (oxalate and EGTA) are impaired in ROS production. Moreover, leaves treated with verapamil, EGTA or oxalate were more susceptible to B. cinerea after wounding. The intracellular measurements of calcium changes indicated quick but transient calcium dynamics taking place few seconds after wounding in cells neighbouring the wound site. This change in the cytosolic calcium was followed in the same region by a more stable ROS burst. Conclusions These data further extend our knowledge on the connection between wounding, calcium influx and ROS production. Moreover they provide for the first time the evidence that, following wounding, calcium changes precede a burst in ROS in the same location. PMID:24134148

2013-01-01

269

Recent studies suggest that human activities accelerate the production of reactive nitrogen on a global scale. Increased  

E-print Network

pollution, reduced visibility, changes in biodiversity, and stratospheric ozone depletion. In the last 50 yr the detrimental environmental effects of current food, fiber, and feed production activities. This paper focuses Emissions of air pollutants, particularly ammonia, during agri- cultural operations are an important

Niyogi, Dev

270

The role of local renin-angiotensin system on high glucose-induced cell toxicity, apoptosis and reactive oxygen species production in PC12 cells  

PubMed Central

Objective(s): Hyperglycemia, oxidative stress and apoptosis have key roles in pathogenesis of diabetic neuropathy. There are local renin-angiotensin systems (RASs) in different tissues such as neural tissue. Local RASs are involved in physiological and pathophysiological processes such as inflammation, proliferation and apoptosis. This study aimed to investigate the role of local renin-angiotensin system on high glucose-induced cell toxicity, apoptosis and reactive oxygen species (ROS) production in PC12 cells, as a cell model of diabetic neuropathy. Materials and Methods: PC12 cells were exposed to a high glucose concentration (27 mg/ml), captopril (ACE inhibitor), telmisartan and losartan (AT1 antagonists), and also PD123319 (AT2 antagonist) were administered before and after induction of high glucose toxicity. Then cell viability was assessed by MTT assay and apoptotic cells and intracellular ROS production were detected by annexin V-propidium iodide and DCFDA, respectively, using flow cytometry. Results: High glucose concentration decreased cell viability, and increased apoptotic cells. Intracellular ROS production was also increased. In PC12 cells pretreatment and treatment by the drugs showed a significant improvement in cell viability and reduced apoptosis in captopril, telmisartan and PD123319 but only captopril and telmisartan were able to reduce ROS production. Losrtan significantly lowered ROS but didn't show any improvements in cell viability and apoptotic cells. Conclusion: The results of the present study showed that RAS inhibitors reduced cell toxicity and apoptosis and ROS production was induced by high glucose. It may be suggested that local RAS has a role in high glucose toxicity.

Shahveisi, Kaveh; Mousavi, Seyed Hadi; Hosseini, Mahmoud; Rad, Abolfazl Khajavi; Jalali, Seyed Amir; Rajaei, Ziba; Sadeghnia, Hamid Reza; Hadjzadeh, Mousa-Al-Reza

2014-01-01

271

Observation of vertical motion above a subduction zone using Persistent Scatterer Interferometry Wide Area Product, SW Crete  

NASA Astrophysics Data System (ADS)

Persistent scatterer interferometry (PSI) is a powerful tool to quantify vertical motion of the Earth's surface with millimeter accuracy at a wide spatial coverage of hundreds of square km. Persistent Scatterers (PS) are phase stable point targets with a consistent and strong reflectivity observed over a long time (Ferretti et al., 2001, IEEE Transactions on Geoscience and Remote Sensing). These PS originate from man-made features, or natural features like rocks. This technique, which was originally developed for urban areas (Ferretti et al., 2001, IEEE Transactions on Geoscience and Remote Sensing), is now enhanced and applied for the detection of PS in rural areas by the operational PSI system Wide Area Product (PSI-GENESIS) of the German Aerospace Center (DLR). The detection is possible over large areas (100 km by 100 km). A problem with the wide-area approach is to cope with inhomogeneous PS densities within an area and variable topography. Difficulties arise from uncompensated atmospheric effects and spatial error propagation. The number of available scenes per stack is limited but the amount of data to be processed is large (about 1 Gigabyte per stack). We tested the PSI technique for the island of Crete. Therefore, we used data of the ERS-1 and ERS-2 satellites of the European Space Agency (ESA) for the PSI analysis. The western part of the island is covered by 39 Synthetic Aperture Radar (SAR) images acquired between 1992 and 2000 of the ERS Track 193. We chose the island of Crete as test site due to its close location to the Hellenic subduction zone, which allows the observation of vertical surface motion. Crete is bounded by seismogenic faults that produced large and destructive earthquakes in the past, such as the MS > 8 earthquake in 365 AD. Vertical surface motion in the vicinity of a subduction zone may imply locking of the plate interface. Our preliminary findings of the W part of the island show an inhomogeneous distribution of PS over the whole scene. The northern part of Crete is more flat than the southern part, which leads to a more homogenous PS distribution in the North. The southern part consists of high mountain ranges, therefore the detection of PS is only possible outside the radar shadows. The northern part shows no significant vertical motion pattern. The southern coast shows uplift in the range of 3 mm/yr. The SW corner of the island shows a strong uplift of up to 5 mm/yr. Further analysis is still in progress and additional atmospheric corrections are necessary to validate our results. We interpret the observed vertical motion in Crete as interseismic strain accumulation. This implies that the subduction zone interface is at least partly locked and hence, may produce another large earthquake in the future.

Rieger, S. M.; Adam, N.; Friedrich, A. M.

2011-12-01

272

In vitro reactive oxygen species production by mitochondria from the rabbitfish Siganus fuscessens livers and the effects of Irgarol-1051.  

PubMed

In this study, the mitochondria from the livers of Siganus fuscessens were exposed to the Irgarol-1051with or without respiratory chain inhibitors using succinate or malate as the substrate, and the effects on mitochondrial ROS production were tested. The mitochondrial ROS production was significantly enhanced by antimycin A with an increase of more than three folds but not by rotenone and NaN3, and this may suggest complex III is the major ROS-producing site. Irgarol-1051 treatments gave a somewhat contradictory result: this chemical can inhibit the mitochondrial ROS production but the inhibition decreased with the increase of doses. These contradictory data about Irgarol-1051 may be explained by the balance between the effects of inhibition through the opening of small-size pores and stimulation through blocking electron transfer, but the mechanism laid behind needs more evidence to support. As Irgarol-1051 was continuously used in antifouling and its bio-concentration factor is up to 160 in fish, the toxic effect of Irgarol-1051 on aquatic animals should be paid more attention to. PMID:23328116

Liang, Bo; Wang, Li; He, Tangtian; Liu, Wenhua; Li, Qi; Li, Mingfeng

2013-03-01

273

Reactive collisions of sulfur dioxide with molten carbonates  

PubMed Central

Molecular beam scattering experiments are used to investigate reactions of SO2 at the surface of a molten alkali carbonate eutectic at 683 K. We find that two-thirds of the SO2 molecules that thermalize at the surface of the melt are converted to gaseous CO2 via the reaction . The CO2 product is formed from SO2 in less than 10-6 s, implying that the reaction takes place in a shallow liquid region less than 100 ? deep. The reaction probability does not vary between 683 and 883 K, further implying a compensation between decreasing SO2 residence time in the near-interfacial region and increasing reactivity at higher temperatures. These results demonstrate the remarkable efficiency of SO2 ? CO2 conversion by molten carbonates, which appear to be much more reactive than dry calcium carbonate or wet slurries commonly used for flue gas desulfurization in coal-burning power plants. PMID:20133648

Krebs, Thomas; Nathanson, Gilbert M.

2010-01-01

274

Atmospheric reactivity of hydroxyl radicals with guaiacol (2-methoxyphenol), a biomass burning emitted compound: Secondary organic aerosol formation and gas-phase oxidation products  

NASA Astrophysics Data System (ADS)

Methoxyphenols are low molecular weight semi-volatile polar aromatic compounds produced from the pyrolysis of wood lignin. The reaction of guaiacol (2-methoxyphenol) with hydroxyl radicals has been studied in the LPCA simulation chamber at (294 ± 2) K, atmospheric pressure, low relative humidity (RH < 1%) and under high-NOx conditions using CH3ONO as OH source. The aerosol production was monitored using a SMPS (Scanning Mobility Particle Sizer); the SOA yields were in the range from 0.003 to 0.87 and the organic aerosol formation can be expressed by a one-product gas/particle partitioning absorption model. Transmission (TEM) and Scanning (SEM) Electron Microscopy observations were performed to characterize the physical state of SOA produced from the OH reaction with guaiacol; they display both liquid and solid particles (in an amorphous state). GC-FID (Gas Chromatography - Flame Ionization Detection) and GC-MS (Gas Chromatography - Mass Spectrometry) analysis show the formation of nitroguaiacol isomers as main oxidation products in the gas- and aerosol-phases. In the gas-phase, the formation yields were (10 ± 2) % for 4-nitroguaiacol (1-hydroxy-2-methoxy-4-nitrobenzene; 4-NG) and (6 ± 2) % for 3- or 6-nitroguaiacol (1-hydroxy-2-methoxy-3-nitrobenzene or 1-hydroxy-2-methoxy-6-nitrobenzene; 3/6-NG; the standards are not commercially available so both isomers cannot be distinguished) whereas in SOA their yield were much lower (?0.1%). To our knowledge, this work represents the first identification of nitroguaiacols as gaseous oxidation products of the OH reaction with guaiacol. As the reactivity of nitroguaiacols with atmospheric oxidants is probably low, we suggest using them as biomass burning emission gas tracers. The atmospheric implications of the guaiacol + OH reaction are also discussed.

Lauraguais, Amélie; Coeur-Tourneur, Cécile; Cassez, Andy; Deboudt, Karine; Fourmentin, Marc; Choël, Marie

2014-04-01

275

Methyl jasmonate induces production of reactive oxygen species and alterations in mitochondrial dynamics that precede photosynthetic dysfunction and subsequent cell death.  

PubMed

Methyl jasmonate (MeJa) is a well-known plant stress hormone. Upon exposure to stress, MeJa is produced and causes activation of programmed cell death (PCD) and defense mechanisms in plants. However, the early events and the signaling mechanisms of MeJa-induced cell death have yet to be fully elucidated. To obtain some insights into the early events of this cell death process, we investigated mitochondrial dynamics, chloroplast morphology and function, production and localization of reactive oxygen species (ROS) at the single-cell level as well as photosynthetic capacity at the whole-seedling level under MeJa stimulation. Our results demonstrated that MeJa induction of ROS production, which first occurred in mitochondria after 1 h of MeJa treatment and subsequently in chloroplasts by 3 h of treatment, caused a series of alterations in mitochondrial dynamics including the cessation of mitochondrial movement, the loss of mitochondrial transmembrane potential (MPT), and the morphological transition and aberrant distribution of mitochondria. Thereafter, photochemical efficiency dramatically declined before obvious distortion in chloroplast morphology, which is prior to MeJa-induced cell death in protoplasts or intact seedlings. Moreover, treatment of protoplasts with ascorbic acid or catalase prevented ROS production, organelle change, photosynthetic dysfunction and subsequent cell death. The permeability transition pore inhibitor cyclosporin A gave significant protection against MPT loss, mitochondrial swelling and subsequent cell death. These results suggested that MeJa induces ROS production and alterations of mitochondrial dynamics as well as subsequent photosynthetic collapse, which occur upstream of cell death and are necessary components of the cell death process. PMID:18535010

Zhang, Lingrui; Xing, Da

2008-07-01

276

Cryptogein-induced initial events in tobacco BY-2 cells: pharmacological characterization of molecular relationship among cytosolic Ca(2+) transients, anion efflux and production of reactive oxygen species.  

PubMed

Ion fluxes and the production of reactive oxygen species (ROS) are early events that follow elicitor treatment or microbial infection. However, molecular mechanisms for these responses as well as their relationship have been controversial and still largely unknown. We here simultaneously monitored the temporal sequence of initial events at the plasma membrane in suspension-cultured tobacco cells (cell line BY-2) in response to a purified proteinaceous elicitor, cryptogein, which induced hypersensitive cell death. The elicitor induced transient rise in cytosolic Ca(2+) concentration ([Ca(2+)](cyt)) showing two distinct peaks, followed by biphasic (rapid/transient and slow/prolonged) Cl(-) efflux and H(+) influx. Pharmacological analyses suggested that the two phases of the [Ca(2+)](cyt) response correspond to Ca(2+) influx through the plasma membrane and an inositol 1,4,5-trisphophate-mediated release of Ca(2+) from intracellular Ca(2+) stores, respectively, and the [Ca(2+)](cyt) transients and the Cl(-) efflux were mutually dependent events regulated by protein phosphorylation. The elicitor also induced production of ROS including (*)O(2)(-) and H(2)O(2), which initiated after the [Ca(2+)](cyt) rise and required Ca(2+) influx, Cl(-) efflux and protein phosphorylation. An inhibitor of NADPH oxidase, diphenylene iodonium, completely inhibited the elicitor-induced production of (*)O(2)(-) and H(2)O(2), but did not affect the [Ca(2+)](cyt) transients. These results suggest that cryptogein-induced plasma membrane Ca(2+) influx is independent of ROS, and NADPH oxidase dependent ROS production is regulated by these series of ion fluxes. PMID:14988486

Kadota, Yasuhiro; Goh, Tatsuaki; Tomatsu, Hajime; Tamauchi, Ryosuke; Higashi, Katsumi; Muto, Shoshi; Kuchitsu, Kazuyuki

2004-02-01

277

Proteomic Phenotyping of Novosphingobium nitrogenifigens Reveals a Robust Capacity for Simultaneous Nitrogen Fixation, Polyhydroxyalkanoate Production, and Resistance to Reactive Oxygen Species  

PubMed Central

Novosphingobium nitrogenifigens Y88T (Y88) is a free-living, diazotrophic Alphaproteobacterium, capable of producing 80% of its biomass as the biopolymer polyhydroxybutyrate (PHB). We explored the potential utility of this species as a polyhydroxybutyrate production strain, correlating the effects of glucose, nitrogen availability, dissolved oxygen concentration, and extracellular pH with polyhydroxybutyrate production and changes in the Y88 proteomic profile. Using two-dimensional differential in-gel electrophoresis and tandem mass spectrometry, we identified 217 unique proteins from six growth conditions. We observed reproducible, characteristic proteomic signatures for each of the physiological states we examined. We identified proteins that changed in abundance in correlation with either nitrogen fixation, dissolved oxygen concentration, or acidification of the growth medium. The proteins that correlated with nitrogen fixation were identified either as known nitrogen fixation proteins or as novel proteins that we predict play roles in aspects of nitrogen fixation based on their proteomic profiles. In contrast, the proteins involved in central carbon and polyhydroxybutyrate metabolism were constitutively abundant, consistent with the constitutive polyhydroxybutyrate production that we observed in this species. Three proteins with roles in detoxification of reactive oxygen species were identified in this obligate aerobe. The most abundant protein in all experiments was a polyhydroxyalkanoate granule-associated protein, phasin. The full-length isoform of this protein has a long, intrinsically disordered Ala/Pro/Lys-rich N-terminal segment, a feature that appears to be unique to sphingomonad phasins. The data suggest that Y88 has potential as a PHB production strain due to its aerobic tolerance and metabolic orientation toward polyhydroxybutyrate accumulation, even in low-nitrogen growth medium. PMID:22582058

Strabala, Timothy J.; Peng, Lifeng; Rawson, Pisana; Lloyd-Jones, Gareth; Jordan, T. William

2012-01-01

278

Identification and determination of individual sophorolipids in fermentation products by gradient elution high-performance liquid chromatography with evaporative light-scattering detection.  

PubMed

High-performance liquid chromatography (HPLC) was used for the characterization of sophorolipids, one of the most important types of glycolipid biosurfactants. By using gradient elution with a water-acetonitrile mixture on a reversed-phase (C18) column and evaporative light-scattering detection, resolution of all the important individual sophorolipids present in fermentation products was achieved. In addition to HPLC, a combination of techniques involving selective production by fermentation of sophorolipids, chemical conversions of the products, separation methods and, for identification of lipidic chains of sophorolipids, gas chromatography and mass spectrometry was used. This led to the identification of almost all significant compounds observed in HPLC, including several previously unreported sophorolipids. As a result, a rapid method is now available for investigations of the influence of fermentation conditions on the nature and quantitative distribution of the sophorolipid products obtained. PMID:8245170

Davila, A M; Marchal, R; Monin, N; Vandecasteele, J P

1993-10-01

279

?-Glucan Induces Reactive Oxygen Species Production in Human Neutrophils to Improve the Killing of Candida albicans and Candida glabrata Isolates from Vulvovaginal Candidiasis  

PubMed Central

Vulvovaginal candidiasis (VVC) is among the most prevalent vaginal diseases. Candida albicans is still the most prevalent species associated with this pathology, however, the prevalence of other Candida species, such as C. glabrata, is increasing. The pathogenesis of these infections has been intensely studied, nevertheless, no consensus has been reached on the pathogenicity of VVC. In addition, inappropriate treatment or the presence of resistant strains can lead to RVVC (vulvovaginal candidiasis recurrent). Immunomodulation therapy studies have become increasingly promising, including with the ?-glucans. Thus, in the present study, we evaluated microbicidal activity, phagocytosis, intracellular oxidant species production, oxygen consumption, myeloperoxidase (MPO) activity, and the release of tumor necrosis factor ? (TNF-?), interleukin-8 (IL-8), IL-1?, and IL-1Ra in neutrophils previously treated or not with ?-glucan. In all of the assays, human neutrophils were challenged with C. albicans and C. glabrata isolated from vulvovaginal candidiasis. ?-glucan significantly increased oxidant species production, suggesting that ?-glucan may be an efficient immunomodulator that triggers an increase in the microbicidal response of neutrophils for both of the species isolated from vulvovaginal candidiasis. The effects of ?-glucan appeared to be mainly related to the activation of reactive oxygen species and modulation of cytokine release. PMID:25229476

Bonfim-Mendonca, Patricia de Souza; Ratti, Bianca Altrao; Godoy, Janine da Silva Ribeiro; Negri, Melyssa; de Lima, Nayara Cristina Alves; Fiorini, Adriana; Hatanaka, Elaine; Consolaro, Marcia Edilaine Lopes; de Oliveira Silva, Sueli; Svidzinski, Terezinha Inez Estivalet

2014-01-01

280

Trichostatin A Targets the Mitochondrial Respiratory Chain, Increasing Mitochondrial Reactive Oxygen Species Production to Trigger Apoptosis in Human Breast Cancer Cells  

PubMed Central

Aim Histone deacetylase inhibitors (HDACIs)-based therapies have stimulated interest via their anti-tumor activities, including apoptosis induction, cell cycle arrest, cell differentiation, and autophagy. However, the mechanisms of HDACI-associated anti-tumor activity are not yet clearly defined. The aim of this study was to explore the key events of Trichostatin A (TSA), a classic HDACI agent, against breast cancer cells. Methods The MCF-7, MDA-MB-231 and MCF-10A cell lines were evaluated with colony-forming and cell viability assays. Apoptosis and cell cycle distribution were detected by flow cytometry. Mitochondrial function was measured with biochemical assays, flow cytometry and transmission electron microscopy. Results TSA inhibited breast cancer cell viability and proliferation, without affecting MCF-10A cell. TSA-induced breast cancer cell apoptosis was initiated by G2-M arrest and depended on mitochondrial reactive oxygen species (ROS) produced subsequent to reduced mitochondrial respiratory chain activity. The enhanced mitochondrial ROS production and apoptosis in cancer cells were markedly attenuated by antioxidants, such as N-acetyl cysteine (NAC), reduced glutathione (GSH) and Vitamin C. Conclusion The present study demonstrated that TSA-induced cell death by arresting cell cycle in G2-M phase and was dependent on production of mitochondria-derived ROS, which was derived from impaired mitochondrial respiratory chain. PMID:24626188

Liu, Jia; Fang, Yong; Tian, Yuan; Zhou, Jianfeng; Ma, Ding; Wu, Peng

2014-01-01

281

Advanced Glycation End Products Induce Human Corneal Epithelial Cells Apoptosis through Generation of Reactive Oxygen Species and Activation of JNK and p38 MAPK Pathways  

PubMed Central

Advanced Glycation End Products (AGEs) has been implicated in the progression of diabetic keratopathy. However, details regarding their function are not well understood. In the present study, we investigated the effects of intracellular reactive oxygen species (ROS) and JNK, p38 MAPK on AGE-modified bovine serum albumin (BSA) induced Human telomerase-immortalized corneal epithelial cells (HUCLs) apoptosis. We found that AGE-BSA induced HUCLs apoptosis and increased Bax protein expression, decreased Bcl-2 protein expression. AGE-BSA also induced the expression of receptor for advanced glycation end product (RAGE). AGE-BSA-RAGE interaction induced intracellular ROS generation through activated NADPH oxidase and increased the phosphorylation of p47phox. AGE-BSA induced HUCLs apoptosis was inhibited by pretreatment with NADPH oxidase inhibitors, ROS quencher N-acetylcysteine (NAC) or neutralizing anti-RAGE antibodies. We also found that AGE-BSA induced JNK and p38 MAPK phosphorylation. JNK and p38 MAPK inhibitor effectively blocked AGE-BSA-induced HUCLs apoptosis. In addition, NAC completely blocked phosphorylation of JNK and p38 MAPK induced by AGE-BSA. Our results indicate that AGE-BSA induced HUCLs apoptosis through generation of intracellular ROS and activation of JNK and p38 MAPK pathways. PMID:23776698

Yang, Hongling; Wu, Xinyi

2013-01-01

282

Spatial and temporal nature of reactive oxygen species production and programmed cell death in elm (Ulmus pumila L.) seeds during controlled deterioration.  

PubMed

Seed deterioration is poorly understood and remains an active area for research. Seeds of elm (Ulmus pumila L.) were aged at 37 °C above water [controlled deterioration treatment (CDT)] for various lengths of time to assess programmed cell death (PCD) and reactive oxygen species (ROS) product in embryonic tissues during a 5?d period. The hallmarks of PCD were identified in the elm seeds during CDT including TUNEL experiments, DNA laddering, cytochrome c (cyt c) leakage and enzymatic activities. These analyses indicated that PCD occurred systematically and progressively in deteriorated elm seeds. Cyt c release and increase in caspase-3-like/DEVDase activity occurred during CDT, which could be suppressed by ascorbic acid (AsA) and caspase-3 inhibitor Ac-DEVD-CHO, respectively. In situ localization of ROS production indicated that the distinct spatial-temporal signature of ROS during CDT coincided with the changes in PCD hallmark features. Multiple antioxidant elements were activated during the first few days of CDT, but were subsequently depleted as PCD progressed. Taken together, our findings identify PCD as a key mechanism that occurs asymmetrically during elm seeds CDT and suggest an important role for PCD in seeds deterioration. PMID:22582978

Hu, Die; Ma, Gang; Wang, Qiong; Yao, Jinghan; Wang, Yu; Pritchard, Hugh W; Wang, Xiaofeng

2012-11-01

283

Ionizing radiation accelerates Drp1-dependent mitochondrial fission, which involves delayed mitochondrial reactive oxygen species production in normal human fibroblast-like cells  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer We report first time that ionizing radiation induces mitochondrial dynamic changes. Black-Right-Pointing-Pointer Radiation-induced mitochondrial fission was caused by Drp1 localization. Black-Right-Pointing-Pointer We found that radiation causes delayed ROS from mitochondria. Black-Right-Pointing-Pointer Down regulation of Drp1 rescued mitochondrial dysfunction after radiation exposure. -- Abstract: Ionizing radiation is known to increase intracellular level of reactive oxygen species (ROS) through mitochondrial dysfunction. Although it has been as a basis of radiation-induced genetic instability, the mechanism involving mitochondrial dysfunction remains unclear. Here we studied the dynamics of mitochondrial structure in normal human fibroblast like cells exposed to ionizing radiation. Delayed mitochondrial O{sub 2}{sup {center_dot}-} production was peaked 3 days after irradiation, which was coupled with accelerated mitochondrial fission. We found that radiation exposure accumulated dynamin-related protein 1 (Drp1) to mitochondria. Knocking down of Drp1 expression prevented radiation induced acceleration of mitochondrial fission. Furthermore, knockdown of Drp1 significantly suppressed delayed production of mitochondrial O{sub 2}{sup {center_dot}-}. Since the loss of mitochondrial membrane potential, which was induced by radiation was prevented in cells knocking down of Drp1 expression, indicating that the excessive mitochondrial fission was involved in delayed mitochondrial dysfunction after irradiation.

Kobashigawa, Shinko, E-mail: kobashin@nagasaki-u.ac.jp [Atomic Bomb Disease Institute, Course of Life Sciences and Radiation Research, Nagasaki University Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki 852-8523 (Japan)] [Atomic Bomb Disease Institute, Course of Life Sciences and Radiation Research, Nagasaki University Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki 852-8523 (Japan); Suzuki, Keiji; Yamashita, Shunichi [Atomic Bomb Disease Institute, Course of Life Sciences and Radiation Research, Nagasaki University Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki 852-8523 (Japan)] [Atomic Bomb Disease Institute, Course of Life Sciences and Radiation Research, Nagasaki University Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki 852-8523 (Japan)

2011-11-04

284

Platelet hyperaggregability in high-fat fed rats: A role for intraplatelet reactive-oxygen species production  

PubMed Central

Background Adiposity greatly increases the risk of atherothrombotic events, a pathological condition where a chronic state of oxidative stress is reported to play a major role. This study aimed to investigate the involvement of (NO)-soluble guanylyl cyclase (sGC) signaling pathway in the platelet dysfunction from high fat-fed (HFF) rats. Methods Male Wistar rats were fed for 10 weeks with standard chow (SCD) or high-fat diet (HFD). ADP (10 ?M)- and thrombin (100 mU/ml)-induced washed platelet aggregation were evaluated. Measurement of intracellular levels of ROS levels was carried out using flow cytometry. Cyclic GMP levels were evaluated using ELISA kits. Results High-fat fed rats exhibited significant increases in body weight, epididymal fat, fasting glucose levels and glucose intolerance compared with SCD group. Platelet aggregation induced by ADP (n = 8) and thrombin from HFD rats (n = 8) were significantly greater (P < 0.05) compared with SCD group. Platelet activation with ADP increased by 54% the intraplatelet ROS production in HFD group, as measured by flow cytometry (n = 6). N-acetylcysteine (NAC; 1 mM) and PEG-catalase (1000 U/ml) fully prevented the increased ROS production and platelet hyperaggregability in HFD group. The NO donors sodium nitroprusside (SNP; 10 ?M) and SNAP (10 ?M), as well as the NO-independent soluble guanylyl cyclase stimulator BAY 41-2272 (10 ?M) inhibited the platelet aggregation in HFD group with lower efficacy (P < 0.05) compared with SCD group. The cGMP levels in response to these agents were also markedly lower in HFD group (P < 0.05). The prostacyclin analogue iloprost (1 ?M) reduced platelet aggregation in HFD and SCD rats in a similar fashion (n = 4). Conclusions Metabolic abnormalities as consequence of HFD cause platelet hyperaggregability involving enhanced intraplatelet ROS production and decreased NO bioavailability that appear to be accompanied by potential defects in the prosthetic haem group of soluble guanylyl cyclase. PMID:22248260

2012-01-01

285

Arrays of microplasmas for the controlled production of tunable high fluxes of reactive oxygen species at atmospheric pressure  

NASA Astrophysics Data System (ADS)

The atmospheric-pressure generation of singlet delta oxygen (O2(a 1?g)) by microplasmas was experimentally studied. The remarkable stability of microcathode sustained discharges (MCSDs) allowed the operation of dc glow discharges, free from the glow-to-arc transition, in He/O2/NO mixtures at atmospheric pressure. From optical diagnostics measurements we deduced the yield of O2(a 1?g). By operating arrays of several MCSDs in series, O2(a 1?g) densities higher than 1.0 × 1017 cm-3 were efficiently produced and transported over distances longer than 50 cm, corresponding to O2(a 1?g) partial pressures and production yields greater than 5 mbar and 6%, respectively. At such high O2(a 1?g) densities, the fluorescence of the so-called O2(a 1?g) dimol was observed as a red glow at 634 nm up to 1 m downstream. Parallel operation of arrays of MCSDs was also implemented, generating O2(a 1?g) fluxes as high as 100 mmol h-1. In addition, ozone (O3) densities up to 1016 cm-3 were obtained. Finally, the density ratio of O2(a 1?g) to O3 was finely and easily tuned in the range [10-3-10+5], through the values of the discharge current and NO concentration. This opens up opportunities for a large spectrum of new applications, making this plasma source notably very useful for biomedicine.

Sousa, J. S.; Bauville, G.; Puech, V.

2013-06-01

286

Oxidatively modified GST and MRP1 in Alzheimer's disease brain: implications for accumulation of reactive lipid peroxidation products.  

PubMed

Alzheimer disease (AD) is a neurodegenerative disorder characterized pathologically by intracellular inclusions including neurofibrillary tangles (NFT) and senile plaques. Several lines of evidence implicate oxidative stress with the progression of AD. 4-hydroxy-2-trans-nonenal (HNE), an aldehydic product of membrane lipid peroxidation, is increased in AD brain. The alpha class of glutathione S-transferase (GST) can detoxify HNE and plays an important role in cellular protection against oxidative stress. The export of the glutathione conjugate of HNE is required to fully potentiate the GST-mediated protection. The multidrug resistance protein-1 (MRP1) and GST proteins may act in synergy to confer cellular protection. In the present study, we studied oxidative modification of GST and MRP1 in AD brain by immunoprecipitation of GST and MRP1 proteins followed by Western blot analysis using anti-HNE antibody. The results suggested that HNE is covalently bound to GST and MRP1 proteins in excess in AD brain. Collectively, the data suggest that HNE may be an important mediator of oxidative stress-induced impairment of this detoxifying system and may thereby play a role in promoting neuronal cell death. The results from this study also imply that augmenting endogenous oxidative defense capacity through dietary or pharmacological intake of antioxidants may slow down the progression of neurodegenerative processes in AD. PMID:15672542

Sultana, Rukhsana; Butterfield, D Allan

2004-12-01

287

Preventive Effect of Daiokanzoto (TJ-84) on 5-Fluorouracil-Induced Human Gingival Cell Death through the Inhibition of Reactive Oxygen Species Production  

PubMed Central

Daiokanzoto (TJ-84) is a traditional Japanese herbal medicine (Kampo formulation). While many Kampo formulations have been reported to regulate inflammation and immune responses in oral mucosa, there is no evidence to show that TJ-84 has beneficial effects on oral mucositis, a disease resulting from increased cell death induced by chemotherapeutic agents such as 5-fluorouracil (5-FU). In order to develop effective new therapeutic strategies for treating oral mucositis, we investigated (i) the mechanisms by which 5-FU induces the death of human gingival cells and (ii) the effects of TJ-84 on biological events induced by 5-FU. 5-FU-induced lactate dehydrogenase (LDH) release and pore formation in gingival cells (Sa3 cell line) resulted in cell death. Incubating the cells with 5-FU increased the expression of nucleotide-binding domain and leucine-rich repeat containing PYD-3 (NLRP3) and caspase-1. The cleavage of caspase-1 was observed in 5-FU-treated cells, which was followed by an increased secretion of interleukin (IL)-1?. The inhibition of the NLRP3 pathway slightly decreased the effects of 5-FU on cell viability and LDH release, suggesting that NLRP3 may be in part involved in 5-FU-induced cell death. TJ-84 decreased 5-FU-induced LDH release and cell death and also significantly inhibited the depolarization of mitochondria and the up-regulation of 5-FU-induced reactive oxygen species (ROS) and nitric oxide (NO) production. The transcriptional factor, nuclear factor-?B (NF-?B) was not involved in the 5-FU-induced cell death in Sa3 cells. In conclusion, we provide evidence suggesting that the increase of ROS production in mitochondria, rather than NLRP3 activation, was considered to be associated with the cell death induced by 5-FU. The results also suggested that TJ-84 may attenuate 5-FU-induced cell death through the inhibition of mitochondrial ROS production. PMID:25389767

Yoshida, Kaya; Yoshioka, Masami; Okamura, Hirohiko; Moriyama, Satomi; Kawazoe, Kazuyoshi; Grenier, Daniel; Hinode, Daisuke

2014-01-01

288

Induction of necrosis and apoptosis to KB cancer cells by sanguinarine is associated with reactive oxygen species production and mitochondrial membrane depolarization  

SciTech Connect

Sanguinarine is a benzopheanthridine alkaloid present in the root of Sanguinaria canadensis L. and Chellidonium majus L. In this study, sanguinarine (2 and 3 {mu}M) exhibited cytotoxicity to KB cancer cells by decreasing MTT reduction to 83% and 52% of control after 24-h of exposure. Sanguinarine also inhibited the colony forming capacity (> 52-58%) and growth of KB cancer cells at concentrations higher than 0.5-1 {mu}M. Short-term exposure to sanguinarine (> 0.5 {mu}M) effectively suppressed the adhesion of KB cells to collagen and fibronectin (FN). Sanguinarine (2 and 3 {mu}M) induced evident apoptosis as indicated by an increase in sub-G0/G1 populations, which was detected after 6-h of exposure. Only a slight increase in cells arresting in S-phase and G2/M was noted. Induction of KB cell apoptosis and necrosis by sanguinarine (2 and 3 {mu}M) was further confirmed by Annexin V-PI dual staining flow cytometry and the presence of DNA fragmentation. The cytotoxicity by sanguinarine was accompanied by an increase in production of reactive oxygen species (ROS) and depolarization of mitochondrial membrane potential as indicated by single cell flow cytometric analysis of DCF and rhodamine fluorescence. NAC (1 and 3 mM) and catalase (2000 U/ml) prevented the sanguinarine-induced ROS production and cytotoxicity, whereas dimethylthiourea (DMT) showed no marked preventive effect. These results suggest that sanguinarine has anticarcinogenic properties with induction of ROS production and mitochondrial membrane depolarization, which mediate cancer cell death.

Chang, M.-C. [Biomedical Science Team, Chang Gung Institute of Technology, Taoyuan, Taiwan (China); Chan, C.-P. [Department of Dentistry, Chang Gung Memorial Hospital, Taipei, Taiwan (China); Wang, Y.-J. [Department of Environmental Medicine, National Cheng Kung University, Tainan, Taiwan (China); Lee, P.-H. [Biomedical Science Team, Chang Gung Institute of Technology, Taoyuan, Taiwan (China); Chen, L.-I [Laboratory of Dental Pharmacology and Toxicology, Department of Dentistry, National Taiwan University Hospital and National Taiwan University Medical College, No 1, Chang-Te Street, Taipei, Taiwan (China); Tsai, Y.-L. [Laboratory of Dental Pharmacology and Toxicology, Department of Dentistry, National Taiwan University Hospital and National Taiwan University Medical College, No 1, Chang-Te Street, Taipei, Taiwan (China); Lin, B.-R. [Department of Integrated Diagnostics and Therapeutics, National Taiwan University Hospital, Taiwan (China); Wang, Y.-L. [Department of Environmental Medicine, National Cheng Kung University, Tainan, Taiwan (China); Jeng, J.-H. [Laboratory of Dental Pharmacology and Toxicology, Department of Dentistry, National Taiwan University Hospital and National Taiwan University Medical College, No 1, Chang-Te Street, Taipei, Taiwan (China)]. E-mail: huei@ha.mc.ntu.edu.tw

2007-01-15

289

Polyenylpyrrole Derivatives Inhibit NLRP3 Inflammasome Activation and Inflammatory Mediator Expression by Reducing Reactive Oxygen Species Production and Mitogen-Activated Protein Kinase Activation  

PubMed Central

Two polyenylpyrroles from a soil ascomycete Gymnoascus reessii were previously identified as hit compounds in screening for cytotoxicity against lung cancer cells. These compounds and various analogs, which have been previously synthesized and tested for anti-lung cancer cell activity, were tested for anti-inflammatory activity. After preliminary screening for cytotoxicity for RAW 264.7 murine macrophage cells, the non-toxic compounds were tested for anti-inflammatory activity using lipopolysaccharide (LPS)-activated RAW 264.7 cells. Compounds 1h, 1i, and 1n reduced LPS-induced nitric oxide (NO) production, with respective ED50 values of 15 ± 2, 16 ± 2, and 17 ± 2 µM. They also reduced expression of inducible NO synthase and interleukin-6 (IL-6) without affecting cyclooxygenase-2 expression. Compound 1h also reduced secretion of IL-6 and tumor necrosis factor-? by LPS-activated J774A.1 murine macrophage cells, primary mice peritoneal macrophages, and JAWSII murine bone marrow-derived dendritic cells and reduced NLRP3 inflammasome-mediated interleukin-1? (IL-1?) secretion by LPS + adenosine triphosphate-activated J774A.1 and JAWSII cells. The underlying mechanisms for the anti-inflammatory activity of compound 1h were found to be a decrease in LPS-induced reactive oxygen species (ROS) production, mitogen-activated protein kinase phosphorylation, and NF-?B activation and a decrease in ATP-induced ROS production and PKC-? phosphorylation. These results provide promising insights into the anti-inflammatory activity of these conjugated polyenes and a molecular rationale for future therapeutic intervention in inflammation-related diseases. They also show how compound 1h regulates inflammation and suggest it may be a new source for the development of anti-inflammatory agents to ameliorate inflammation- and NLRP3 inflammasome-related diseases. PMID:24116148

Hua, Kuo-Feng; Chou, Ju-Ching; Lam, Yulin; Tasi, Yu-Ling; Chen, Ann; Ka, Shuk-Man; Fang, Zhanxiong; Liu, May-Lan; Yang, Feng-Ling; Yang, Yu-Liang; Chiu, Yi-Chich; Wu, Shih-Hsiung

2013-01-01

290

Reactive Nitrogen, Ozone and Ozone Production in the Arctic Troposphere and the Impact of Stratosphere-Troposphere Exchange  

NASA Technical Reports Server (NTRS)

We analyze the aircraft observations obtained during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellite (ARCTAS) mission together with the GEOS-5 CO simulation to examine O3 and NOy in the Arctic and sub-Arctic region and their source attribution. Using a number of marker tracers and their probability density distributions, we distinguish various air masses from the background troposphere and examine their contribution to NOx, O3, and O3 production in the Arctic troposphere. The background Arctic troposphere has mean O3 of approximately 60 ppbv and NOx of approximately 25 pptv throughout spring and summer with CO decreases from approximately 145 ppbv in spring to approximately 100 ppbv in summer. These observed CO, NOx and O3 mixing ratios are not notably different from the values measured during the 1988 ABLE-3A and the 2002 TOPSE field campaigns despite the significant changes in the past two decades in processes that could have changed the Arctic tropospheric composition. Air masses associated with stratosphere-troposphere exchange are present throughout the mid and upper troposphere during spring and summer. These air masses with mean O3 concentration of 140-160 ppbv are the most important direct sources of O3 in the Arctic troposphere. In addition, air of stratospheric origin is the only notable driver of net O3 formation in the Arctic due to its sustainable high NOx (75 pptv in spring and 110 pptv in summer) and NOy (approximately 800 pptv in spring and approximately 1100 pptv in summer) levels. The ARCTAS measurements present observational evidence suggesting significant conversion of nitrogen from HNO3 to NOx and then to PAN (a net formation of approximately 120 pptv PAN) in summer when air of stratospheric origin is mixed with tropospheric background during stratosphere-to-troposphere transport. These findings imply that an adequate representation of stratospheric O3 and NOy input are essential in accurately simulating O3 and NOx photochemistry as well as the atmospheric budget of PAN in tropospheric chemistry transport models of the Arctic. Anthropogenic and biomass burning pollution plumes observed during ARCTAS show highly elevated hydrocarbons and NOy (mostly in the form of NOx and PAN), but do not contribute significantly to O3 in the Arctic troposphere except in some of the aged biomass burning plumes sampled during spring. Convection and/or lightning influences are negligible sources of O3 in the Arctic troposphere but can have significant impacts in the upper troposphere in the continental sub-Arctic during summer.

Liang, Q.; Rodriquez, J. M.; Douglass, A. R.; Crawford, J. H.; Apel, E.; Bian, H.; Blake, D. R.; Brune, W.; Chin, M.; Colarco, P. R.; daSilva, A.; Diskin, G. S.; Duncan, B. N.; Huey, L. C.; Knapp, D. J.; Montzka, D. D.; Nielsen, J. E.; Olson, J. R.; Pawson, S.; Weinheimer, A. J.

2011-01-01

291

Reactive oxygen production induced by near-infrared radiation in three strains of the Chl d-containing cyanobacterium Acaryochloris marina  

PubMed Central

Cyanobacteria in the genus Acaryochloris have largely exchanged Chl a with Chl d, enabling them to harvest near-infrared-radiation (NIR) for oxygenic photosynthesis, a biochemical pathway prone to generate reactive oxygen species (ROS). In this study, ROS production under different light conditions was quantified in three Acaryochloris strains (MBIC11017, HICR111A and the novel strain CRS) using a real-time ethylene detector in conjunction with addition of 2-keto-4-thiomethylbutyric acid, a substrate that is converted to ethylene when reacting with certain types of ROS. In all strains, NIR was found to generate less ROS than visible light (VIS). More ROS was generated if strains MBIC11017 and HICR111A were adapted to NIR and then exposed to VIS, while strain CRS demonstrated the opposite behavior. This is the very first study of ROS generation and suggests that Acaryochloris can avoid a considerable amount of light-induced stress by using NIR instead of VIS for its photosynthesis, adding further evolutionary arguments to their widespread appearance. PMID:24555034

Kuhl, Michael

2013-01-01

292

Beam-Target Double Spin Asymmetry ALT in Charged Pion Production from Deep Inelastic Scattering on a Transversely Polarized 3He Target at 1.422  

We report the first measurement of the double-spin asymmetry ALT for charged pion electroproduction in semi-inclusive deep inelastic electron scattering on a transversely polarized 3He target. The kinematics focused on the valence quark region, 0.16 2 2. The corresponding neutron ALT asymmetries were extracted from the measured 3He asymmetries and proton/3He cross section ratios using the effective polarization approximation. These new data probe the transverse momentum dependent parton distribution function gq and therefore provide access to quark spin-orbit correlations. Our results indicate a positive azimuthal asymmetry for ?- production on 3He and the neutron, while our ?+ asymmetries are consistent with zero.

Meziani, Z -E; Michaels, R; Munoz Camacho, C; Nanda, S; Narayan, A; Nelyubin, V; Norum, B; Oh, Y; Osipenko, M; Parno, D; Peng, J C; Phillips, S K; Posik, M; Puckett, A.J. R; Qiang, Y; Rakhman, A; Ransome, R D; Riordan, S; Saha, A; Sawatzky, B; Schulte, E; Shahinyan, A; Shabestari, M H; Sirca, S; Stepanyan, S; Subedi, R; Sulkosky, V; Tang, L -G; Tobias, A; Urciuoli, G M; Vilardi, I; Wang, K; Wojtsekhowski, B; Yan, X; Yao, H; Ye, Y; Ye, Z; Yuan, L; Zhan, X; Zhang, Y -W; Zhao, B; Zheng, X; Zhu, L; Zhu, X

2012-01-30

293

Extent of Mitochondrial Hexokinase II Dissociation During Ischemia Correlates With Mitochondrial Cytochrome c Release, Reactive Oxygen Species Production, and Infarct Size on Reperfusion  

PubMed Central

Background The mechanisms by which ischemic preconditioning (IP) inhibits mitochondrial permeability transition pore opening and, hence, ischemia–reperfusion injury remain unclear. Here we investigate whether and how mitochondria?bound hexokinase 2 (mtHK2) may exert part of the cardioprotective effects of IP. Methods and Results Control and IP Langendorff?perfused rat hearts were subject to ischemia and reperfusion with measurement of hemodynamic function and infarct size. Outer mitochondrial membrane (OMM) permeabilization after ischemia was determined by measuring rates of respiration and H2O2 production in the presence and absence of added cytochrome c in isolated mitochondria and permeabilized fibers. IP prevented OMM permeabilization during ischemia and reduced the loss of mtHK2, but not Bcl?xL, observed in control ischemic hearts. By contrast, treatment of permeabilized fibers with glucose?6?phosphate at pH 6.3 induced mtHK2 loss without OMM permeabilization. However, metabolic pretreatments of the perfused heart chosen to modulate glucose?6?phosphate and intracellular pHi revealed a strong inverse correlation between end?ischemic mtHK2 content and infarct size after reperfusion. Loss of mtHK2 was also associated with reduced rates of creatine phosphate generation during the early phase of reperfusion. This could be mimicked in permeabilized fibers after mtHK2 dissociation. Conclusions We propose that loss of mtHK2 during ischemia destabilizes mitochondrial contact sites, which, when accompanied by degradation of Bcl?xL, induces OMM permeabilization and cytochrome c loss. This stimulates reactive oxygen species production and mitochondrial permeability transition pore opening on reperfusion, leading to infarction. Consequently, inhibition of mtHK2 loss during ischemia could be an important mechanism responsible for the cardioprotection mediated by IP and other pretreatments. PMID:23525412

Pasdois, Philippe; Parker, Joanne Elizabeth; Halestrap, Andrew Philip

2013-01-01

294

Baicalein, an active component of Scutellaria baicalensis Georgi, prevents lysophosphatidylcholine-induced cardiac injury by reducing reactive oxygen species production, calcium overload and apoptosis via MAPK pathways  

PubMed Central

Background Lysophosphatidylcholine (lysoPC), a metabolite from membrane phospholipids, accumulates in the ischemic myocardium and plays an important role in the development of myocardial dysfunction ventricular arrhythmia. In this study, we investigated if baicalein, a major component of Huang Qui, can protect against lysoPC-induced cytotoxicity in rat H9c2 embryonic cardiomyocytes. Methods Cell viability was detected by the MTT assay; ROS levels were assessed using DCFH-DA; and intracellular free calcium concentrations were assayed by spectrofluorophotometer. Cell apoptosis and necrosis were evaluated by the flow cytometry assay and Hoechst staining. Mitogen-Activated Protein Kinases (MAPKs), which included the ERK, JNK, and p38, and the apoptotic mechanisms including Bcl-2/Bax, caspase-3, caspase-9 and cytochrome c pathways were examined by Western blot analysis. The activation of MAPKs was examined by enzyme-linked immunosorbent assay. Results We found that lysoPC induced death and apoptosis of H9c2 cells in a dose-dependent manner. Baicalein could prevent lysoPC-induced cell death, production of reactive oxygen species (ROS), and increase of intracellular calcium concentration in H9c2 cardiomyoctes. In addition, baicalein also inhibited lysoPC-induced apoptosis, with associated decreased pro-apoptotic Bax protein, increased anti-apoptotic Bcl-2 protein, resulting in an increase in the Bcl-2/Bax ratio. Finally, baicalein attenuated lysoPC-induced the expression of cytochrome c, casapase-3, casapase-9, and the phosphorylations of ERK1/2, JNK, and p38. LysoPC-induced ERK1/2, JNK, and p38 activations were inhibited by baicalein. Conclusions Baicalein protects cardiomyocytes from lysoPC-induced apoptosis by reducing ROS production, inhibition of calcium overload, and deactivations of MAPK signaling pathways. PMID:25012390

2014-01-01

295

The Production of Reactive Oxygen Species Is a Universal Action Mechanism of Amphotericin B against Pathogenic Yeasts and Contributes to the Fungicidal Effect of This Drug.  

PubMed

Amphotericin B (AMB) is an antifungal drug that binds to ergosterol and forms pores at the cell membrane, causing the loss of ions. In addition, AMB induces the accumulation of reactive oxygen species (ROS), and although these molecules have multiple deleterious effects on fungal cells, their specific role in the action mechanism of AMB remains unknown. In this work, we studied the role of ROS in the action mechanism of AMB. We determined the intracellular induction of ROS in 44 isolates of different pathogenic yeast species (Candida albicans, Candida parapsilosis, Candida glabrata, Candida tropicalis, Candida krusei, Cryptococcus neoformans, and Cryptococcus gattii). We also characterized the production of ROS in AMB-resistant isolates. We found that AMB induces the formation of ROS in all the species tested. The inhibition of the mitochondrial respiratory chain by rotenone blocked the induction of ROS by AMB and provided protection from the killing action of the antifungal. Moreover, this phenomenon was absent in strains that displayed resistance to AMB. These strains showed an alteration in the respiration rate and mitochondrial membrane potential and also had higher catalase activity than that of the AMB-susceptible strains. Consistently, AMB failed to induce protein carbonylation in the resistant strains. Our data demonstrate that the production of ROS by AMB is a universal and important action mechanism that is correlated with the fungicidal effect and might explain the low rate of resistance to the molecule. Finally, these data provide an opportunity to design new strategies to improve the efficacy of this antifungal. PMID:25155595

Mesa-Arango, Ana Cecilia; Trevijano-Contador, Nuria; Román, Elvira; Sánchez-Fresneda, Ruth; Casas, Celia; Herrero, Enrique; Argüelles, Juan Carlos; Pla, Jesús; Cuenca-Estrella, Manuel; Zaragoza, Oscar

2014-11-01

296

3,3',4,4'-Tetrachlorobiphenyl oxidation in fish, bird and reptile species: relationship to cytochrome P450 1A inactivation and reactive oxygen production.  

PubMed

Previously we showed that the polychlorinated biphenyl 3,3',4,4'-tetrachlorobiphenyl (TCB) caused a release of reactive oxygen species (ROS) from cytochrome P450 1A (CYP1A) of the fish scup (Stenotomus chrysops), and from rat and human CYP1A1. This was linked to a TCB- and NADPH-dependent oxidative inactivation of the enzyme, which in scup and rat was inversely related to the rates of TCB oxidation. We examined the relationship between rates of TCB oxidation, CYP1A inactivation and ROS production in liver microsomes from additional vertebrate species, including skate (Raja erinacea), eel (Anguilla rostrata), killifish (Fundulus heteroclitus), winter flounder (Pleuronectes americanus), chicken (Gallus domesticus), cormorant (Phalacrocorax auritus), gull (Larus argentatus), and turtle (Chrysemys picta picta). TCB oxidation rates were induced in all fish and birds treated with aryl hydrocarbon receptor agonists. Induced rates of TCB oxidation were <1 pmol/min/mg microsomal protein in all fish, and 6-14 pmol/min/mg in the birds. In all species but one, TCB oxidation rates correlated positively with EROD rates, indicating likely involvement of CYP1A in TCB oxidation. Incubation of liver microsomes of most species with TCB+NADPH resulted in an immediate (TCB-dependent) inhibition of EROD, and a progressive loss of EROD capacity, indicating an oxidative inactivation of CYP1A like that in scup. NADPH stimulated production of ROS (H(2)O(2) and/or O(2)(-*)) by liver microsomes, slightly in some species (eel) and greatly in others (chicken, turtle). Among the birds and the fish, NADPH-stimulated ROS production correlated positively with EROD activity. TCB caused a significant stimulation of ROS production by liver microsomes of flounder, killifish, cormorant and gull, as well as scup. The stimulation of CYP1A inactivation and ROS generation indicates an uncoupling of CYP1A by TCB in many species, and when compared between species, the rates of CYP1A inactivation correlated inversely with rates of TCB oxidation. Some feature(s) of binding/active site topology may hinder TCB oxidation, enhancing the likelihood for attack of an oxidizing species in the active site. PMID:11790349

Schlezinger, J J; Keller, J; Verbrugge, L A; Stegeman, J J

2000-03-01

297

Graviton-Photon Scattering  

E-print Network

We use that the gravitational Compton scattering factorizes on the Abelian QED amplitudes to evaluate various gravitational Compton processes. We examine both the QED and gravitational Compton scattering from a massive spin-1 system by the use of helicity amplitudes. In the case of gravitational Compton scattering we show how the massless limit can be used to evaluate the cross-section for graviton-photon scattering and discuss the difference between photon interactions and the zero mass spin-1 limit. We show that the forward scattering cross-section for graviton photo-production has a very peculiar behaviour, differing from the standard Thomson and Rutherford cross-sections for a Coulomb-like potential.

N. E. J. Bjerrum-Bohr; Barry R. Holstein; Ludovic Planté; Pierre Vanhove

2014-10-15

298

Graviton-Photon Scattering  

E-print Network

We use that the gravitational Compton scattering factorizes on the Abelian QED amplitudes to evaluate various gravitational Compton processes. We examine both the QED and gravitational Compton scattering from a massive spin-1 system by the use of helicity amplitudes. In the case of gravitational Compton scattering we show how the massless limit can be used to evaluate the cross-section for graviton-photon scattering and discuss the difference between photon interactions and the zero mass spin-1 limit. We show that the forward scattering cross-section for graviton photo-production has a very peculiar behaviour, differing from the standard Thomson and Rutherford cross-sections for a Coulomb-like potential.

Bjerrum-Bohr, N E J; Planté, Ludovic; Vanhove, Pierre

2014-01-01

299

A high-statistics measurement of transverse spin effects in dihadron production from muon-proton semi-inclusive deep-inelastic scattering  

NASA Astrophysics Data System (ADS)

A measurement of the azimuthal asymmetry in dihadron production in deep-inelastic scattering of muons on transversely polarised proton (NH3) targets is presented. They provide independent access to the transversity distribution functions through the measurement of the Collins asymmetry in single hadron production. The data were taken in the year 2010 with the COMPASS spectrometer using a 160 GeV/c muon beam of the CERN SPS, increasing by a factor of about four the overall statistics with respect to the previously published data taken in the year 2007. The measured sizeable asymmetry is in good agreement with the published data. An approximate equality of the Collins asymmetry and the dihadron asymmetry is observed, suggesting a common physical mechanism in the underlying fragmentation.

Adolph, C.; Akhunzyanov, R.; Alekseev, M. G.; Alexandrov, Yu.; Alexeev, G. D.; Amoroso, A.; Andrieux, V.; Anosov, V.; Austregesilo, A.; Bade?ek, B.; Balestra, F.; Barth, J.; Baum, G.; Beck, R.; Bedfer, Y.; Berlin, A.; Bernhard, J.; Bertini, R.; Bicker, K.; Bieling, J.; Birsa, R.; Bisplinghoff, J.; Bodlak, M.; Boer, M.; Bordalo, P.; Bradamante, F.; Braun, C.; Bravar, A.; Bressan, A.; Büchele, M.; Burtin, E.; Capozza, L.; Chiosso, M.; Chung, S. U.; Cicuttin, A.; Crespo, M. L.; Curiel, Q.; Dalla Torre, S.; Dasgupta, S. S.; Dasgupta, S.; Denisov, O. Yu.; Donskov, S. V.; Doshita, N.; Duic, V.; Dünnweber, W.; Dziewiecki, M.; Efremov, A.; Elia, C.; Eversheim, P. D.; Eyrich, W.; Faessler, M.; Ferrero, A.; Filin, A.; Finger, M.; Finger, M.; Fischer, H.; Franco, C.; du Fresne von Hohenesche, N.; Friedrich, J. M.; Frolov, V.; Garfagnini, R.; Gautheron, F.; Gavrichtchouk, O. P.; Gerassimov, S.; Geyer, R.; Giorgi, M.; Gnesi, I.; Gobbo, B.; Goertz, S.; Gorzellik, M.; Grabmüller, S.; Grasso, A.; Grube, B.; Guskov, A.; Guthörl, T.; Haas, F.; von Harrach, D.; Hahne, D.; Hashimoto, R.; Heinsius, F. H.; Herrmann, F.; Hinterberger, F.; Höppner, Ch.; Horikawa, N.; d'Hose, N.; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jary, V.; Jasinski, P.; Joerg, P.; Joosten, R.; Kabuß, E.; Kang, D.; Ketzer, B.; Khaustov, G. V.; Khokhlov, Yu. A.; Kisselev, Yu.; Klein, F.; Klimaszewski, K.; Koivuniemi, J. H.; Kolosov, V. N.; Kondo, K.; Königsmann, K.; Konorov, I.; Konstantinov, V. F.; Kotzinian, A. M.; Kouznetsov, O.; Kral, Z.; Krämer, M.; Kroumchtein, Z. V.; Kuchinski, N.; Kunne, F.; Kurek, K.; Kurjata, R. P.; Lednev, A. A.; Lehmann, A.; Levorato, S.; Lichtenstadt, J.; Maggiora, A.; Magnon, A.; Makke, N.; Mallot, G. K.; Marchand, C.; Martin, A.; Marzec, J.; Matousek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G.; Meyer, W.; Michigami, T.; Mikhailov, Yu. V.; Miyachi, Y.; Nagaytsev, A.; Nagel, T.; Nerling, F.; Neubert, S.; Neyret, D.; Nikolaenko, V. I.; Novy, J.; Nowak, W.-D.; Nunes, A. S.; Orlov, I.; Olshevsky, A. G.; Ostrick, M.; Panknin, R.; Panzieri, D.; Parsamyan, B.; Paul, S.; Pesek, M.; Peshekhonov, D.; Piragino, G.; Platchkov, S.; Pochodzalla, J.; Polak, J.; Polyakov, V. A.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Reicherz, G.; Rocco, E.; Rodionov, V.; Rondio, E.; Rychter, A.; Rossiyskaya, N. S.; Ryabchikov, D. I.; Samoylenko, V. D.; Sandacz, A.; Sarkar, S.; Savin, I. A.; Sbrizzai, G.; Schiavon, P.; Schill, C.; Schlüter, T.; Schmidt, A.; Schmidt, K.; Schmieden, H.; Schönning, K.; Schopferer, S.; Schott, M.; Shevchenko, O. Yu.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Sosio, S.; Sozzi, F.; Srnka, A.; Steiger, L.; Stolarski, M.; Sulc, M.; Sulej, R.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Takekawa, S.; ter Wolbeek, J.; Tessaro, S.; Tessarotto, F.; Thibaud, F.; Uhl, S.; Uman, I.; Vandenbroucke, M.; Virius, M.; Vondra, J.; Wang, L.; Weisrock, T.; Wilfert, M.; Windmolders, R.; Wi?licki, W.; Wollny, H.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Ziembicki, M.

2014-09-01

300

A general circulation model based calculation of HCl and ClNO2 production from sea salt dechlorination: Reactive Chlorine Emissions Inventory  

NASA Astrophysics Data System (ADS)

As part of the Reactive Chlorine Emissions Inventory, a global model of chemical processes in the marine boundary layer (MBL), Marine Aerosol and Gas Phase Interactions (MAGPI), was developed to calculate direct monthly production of HCl and ClNO2 from sea salt dechlorination on a 2.8 × 2.8 latitude-longitude grid. Sea salt mass and size distributions and associated surface exchange fluxes were calculated using the Canadian General Circulation Model; integrated annual production of sea salt Cl- was 1785 Tg Cl yr-1. Corresponding distributions of gas-phase HNO3, SO2, N2O5, H2O2, O3, H2SO4 and NH3 were calculated using different global chemical transport models in which sea salt reactions were not considered. A chemical scheme was developed to estimate the monthly mean steady-state phase partitioning of product and reactant species at each grid point. Average annual gridded fluxes of HCl and ClNO2 varied spatially from 1 to 300 mg Cl m-2 yr-1 and from 1 to 8 mg Cl m-2 yr-1, respectively. Maxima occurred in polluted coastal regions of the North Atlantic, the western North Pacific and the Mediterranean where up to 20% of the total Cl and 80% of the sub-micron Cl volatilized. In remote oceanic regions, available acidity was insufficient to titrate all sea salt alkalinity, thus, significant HCl was not produced via acid displacement. However, in these regions virtually all HNO3 was scavenged by sea salt. The integrated annual global fluxes for HCl and ClNO2 were 7.6 Tg Cl yr-1 and 0.06 Tg Cl yr-1, respectively; virtually all in the Northern Hemisphere. Largest HCl and ClNO2 fluxes occur in northern hemisphere winter due to high sea salt loading and elevated HNO3, SO2 and N2O5 concentrations. 70% of the HCl dechlorination occurs on particles between 0.75 ?m and 4 ?m radius; ClNO2 volatilized from slightly larger particles. The aerosol pH of each particle size bin equilibrates towards the same value once the alkalinity has been titrated.

Erickson, David J.; Seuzaret, Christophe; Keene, William C.; Gong, Sun Ling

1999-04-01

301

Bcl-2 maintains the mitochondrial membrane potential, but fails to affect production of reactive oxygen species and endoplasmic reticulum stress, in sodium palmitate-induced ?-cell death.  

PubMed

Abstract Background. Sodium palmitate causes apoptosis of ?-cells, and the anti-apoptotic protein Bcl-2 has been shown to counteract this event. However, the exact mechanisms that underlie palmitate-induced pancreatic ?-cell apoptosis and through which pathway Bcl-2 executes the protective effect are still unclear. Methods. A stable Bcl-2-overexpressing RINm5F cell clone (BMG) and its negative control (B45) were exposed to palmitate for up to 8 h, and cell viability, mitochondrial membrane potential (??m), reactive oxygen species (ROS) generation, endoplasmic reticulum (ER) stress, and NF-?B activation were studied in time course experiments. Results. Palmitate exposure for 8 h resulted in increased cell death rates, and this event was partially counteracted by Bcl-2. Bcl-2 overexpression promoted in parallel also a delayed induction of GADD153/CHOP and a weaker phosphorylation of BimEL in palmitate-exposed cells. At earlier time points (2-4 h) palmitate exposure resulted in increased generation of ROS, a decrease in mitochondrial membrane potential (??m), and a modest increase in the phosphorylation of eIF2? and IRE1?. BMG cells produced similar amounts of ROS and displayed the same eIF2? and IRE1? phosphorylation rates as B45 cells. However, the palmitate-induced dissipation of ??m was partially counteracted by Bcl-2. In addition, basal NF-?B activity was increased in BMG cells. Conclusions. Our results indicate that Bcl-2 counteracts palmitate-induced ?-cell death by maintaining mitochondrial membrane integrity and augmenting NF-?B activity, but not by affecting ROS production and ER stress. PMID:25266628

Wang, Xuan; Welsh, Nils

2014-11-01

302

Platelet reactivity in human aortic grafts: a prospective, randomized midterm study of platelet adherence and release products in Dacron and polytetrafluoroethylene conduits  

SciTech Connect

Platelet-related phenomena at the blood-surface interface of randomly placed knitted Dacron (n = 6) and polytetrafluoroethylene (ePTFE) (n = 6) interposition aortic grafts were studied in patients undergoing abdominal aortic aneurysmectomy. Luminal accumulation of platelets was assessed by infusing indium-111-oxine (400 microCi) labeled autologous platelets and imaging grafts at 1 week, 3 months, and 6 months after surgery. Image analysis included an indium ratio technique (comparing aortic graft radioactivity to that of an iliac artery) and a red blood cell technetium subtraction technique (excluding blood pool radioactivity from graft radioactivity, with the heart or iliac artery serving as reference regions). Plasma levels of beta-thromboglobulin and platelet factor 4 were correlated with platelet accumulations on the aortic prostheses. Differences in graft radioactivity or platelet-release products were not evident 1 week after surgery. Three months after implantation, Dacron and ePTFE conduits exhibited 87% and 47% (p less than 0.05) more radioactivity with the indium ratio technique than the iliac artery. Similarly, increased Dacron compared with ePTFE graft radioactivity was noted using technetium subtraction techniques: 71% vs 30% with a heart reference and 26% vs 11% with an iliac artery reference, respectively. Increases in graft radioactivity correlated with increases in both plasma beta-thromboglobulin and platelet factor 4 at 3 months (r = 0.6 to 0.9; p less than 0.05 to 0.001 depending on the imaging technique used). At 6 months, differences did not persist. In fact, technetium subtraction techniques suggested less Dacron conduit reactivity. It is speculated that differences in platelet accumulation and activation associated with different graft substrates may prove clinically important.

Wakefield, T.W.; Shulkin, B.L.; Fellows, E.P.; Petry, N.A.; Spaulding, S.A.; Stanley, J.C.

1989-02-01

303

Food allergen--induced mast cell degranulation is dependent on PI3K-mediated reactive oxygen species production and upregulation of store-operated calcium channel subunits.  

PubMed

The importance of Ca(2+) influx via store-operated calcium channels (SOCs) leading to mast cell degranulation is well known in allergic disease. However, the underlying mechanisms are not fully understood. With food-allergic rat model, the morphology of degranulated mast cell was analysed by toluidine blue stain and electron microscope. Ca(2+) influx via SOCs was checked by Ca(2+) imaging confocal microscope. Furthermore, the mRNA and protein expression of SOCs subunits were investigated using qPCR and Western blot. We found that ovalbumin (OVA) challenge significantly increased the levels of Th2 cytokines and OVA-specific IgE in allergic animals. Parallel to mast cell activation, the levels of histamine in serum and supernatant of rat peritoneal lavage solution were remarkably increased after OVA treatment. Moreover, the Ca(2+) entry through SOCs evoked by thapsigargin was increased in OVA-challenged group. The mRNA and protein expressions of SOC subunits, stromal interaction molecule 1 (STIM1) and Orail (calcium-release-activated calcium channel protein 1), were dramatically elevated under food-allergic condition. Administration of Ebselen, a scavenger of reactive oxygen species (ROS), significantly attenuated OVA sensitization-induced intracellular Ca(2+) rise and upregulation of SOCs subunit expressions. Intriguingly, pretreatment with PI3K-specific inhibitor (Wortmannin) partially abolished the production of ROS and subsequent elevation of SOCs activity and their subunit expressions. Taken together, these results imply that enhancement of SOC-mediated Ca(2+) influx induces mast cell activation, contributing to the pathogenesis of OVA-stimulated food allergy. PI3K-dependent ROS generation involves in modulating the activity of SOCs by increasing the expressions of their subunit. PMID:23672459

Yang, B; Yang, C; Wang, P; Li, J; Huang, H; Ji, Q; Liu, J; Liu, Z

2013-07-01

304

Platelet reactivity in human aortic grafts: a prospective, randomized midterm study of platelet adherence and release products in Dacron and polytetrafluoroethylene conduits.  

PubMed

Platelet-related phenomena at the blood-surface interface of randomly placed knitted Dacron (n = 6) and polytetrafluoroethylene (ePTFE) (n = 6) interposition aortic grafts were studied in patients undergoing abdominal aortic aneurysmectomy. Luminal accumulation of platelets was assessed by infusing indium-111-oxine (400 microCi) labeled autologous platelets and imaging grafts at 1 week, 3 months, and 6 months after surgery. Image analysis included an indium ratio technique (comparing aortic graft radioactivity to that of an iliac artery) and a red blood cell technetium subtraction technique (excluding blood pool radioactivity from graft radioactivity, with the heart or iliac artery serving as reference regions). Plasma levels of beta-thromboglobulin and platelet factor 4 were correlated with platelet accumulations on the aortic prostheses. Differences in graft radioactivity or platelet-release products were not evident 1 week after surgery. Three months after implantation, Dacron and ePTFE conduits exhibited 87% and 47% (p less than 0.05) more radioactivity with the indium ratio technique than the iliac artery. Similarly, increased Dacron compared with ePTFE graft radioactivity was noted using technetium subtraction techniques: 71% vs 30% with a heart reference and 26% vs 11% with an iliac artery reference, respectively. Increases in graft radioactivity correlated with increases in both plasma beta-thromboglobulin and platelet factor 4 at 3 months (r = 0.6 to 0.9; p less than 0.05 to 0.001 depending on the imaging technique used). At 6 months, differences did not persist. In fact, technetium subtraction techniques suggested less Dacron conduit reactivity. It is speculated that differences in platelet accumulation and activation associated with different graft substrates may prove clinically important. PMID:2537433

Wakefield, T W; Shulkin, B L; Fellows, E P; Petry, N A; Spaulding, S A; Stanley, J C

1989-02-01

305

The perils and opportunities of reactive building blocks: Attempted synthesis of new Hg(CN) 2-based coordination polymers and the structures of the resulting products  

NASA Astrophysics Data System (ADS)

The addition of Hg(CN) 2 to an aqueous solution of CoBr 2 and tris(2-aminoethyl)amine (tren) yields an oxidized peroxocobalt(III)-containing ionic complex {[Co(tren)(CN)] 2(?-O 2)}[HgBr 4], which has been characterized structurally. The bromide ligands have migrated to the Lewis acidic Hg(CN) 2 moiety with concomitant transfer of the cyanide groups to the cobalt(III) centre. The potentially non-innocent nature of the Hg(CN) 2 building block is also manifested in its reaction with CuCl 2 and N, N-dimethylethylenediamine (dmeda); recrystallization of the initial precipitate from ammonia yielded the oxalate-containing coordination polymer {(dmeda) 2Cu 2(?-C 2O 4)[Hg(CN) 2Cl] 2Hg(CN) 2}·(H 2O) 1.5. The structure consists of 1D chains of [(dmeda) 2Cu 2(?-C 2O 4)][Hg(CN) 2Cl] 2 units, which are formed by mercury-bridging chloride ligands as well as N-cyano coordination to the opposing sites of the copper dimer. The chains are connected into a 3D CdSO 4-type array via the second Hg(CN) 2 unit binding to the chlorides; adjacent chains are inclined at 59.0°. The structure can also be considered as a pair of inclined (4,4)-grids fused at [Hg(CN) 2Cl 2] 2- centroids. The oxalate might be generated in situ as a result of the NH 3-triggered release of CN - from Hg(CN) 2, its reaction with available copper(II) to yield cyanogen, and the subsequent hydrolysis of (CN) 2. These two products illustrate examples of potentially undesirable side-reactivities of building blocks that must be considered when rationally designing the synthesis of new coordination polymers.

Leznoff, Daniel B.; Katz, Michael J.; Cheng, Leslie K. L.; Draper, Neil D.; Batchelor, Raymond J.

2006-08-01

306

Distribution and production of reactive mercury and dissolved gaseous mercury in surface waters and water/air mercury flux in reservoirs on Wujiang River, Southwest China  

NASA Astrophysics Data System (ADS)

Transformation and distribution of mercury (Hg) species play an important role in the biogeochemical cycling of mercury in aquatic systems. Measurements of water/air exchange fluxes of Hg, reactive mercury (RHg), and dissolved gaseous mercury (DGM) concentrations were conducted at 14 sites in five reservoirs on the Wujiang River, Guizhou, Southwest China. Clear spatial and temporal variations in Hg fluxes, RHg, and DGM concentrations were observed in the study area. Hg fluxes and RHg concentrations exhibited a consistent diurnal variation in the study area, with maximum fluxes and concentrations during daytime. A typical diurnal trend of DGM with elevated concentration at night was observed in a eutrophic reservoir with elevated bacteria abundance, suggesting a bacteria-induced production of DGM in this reservoir. For other reservoirs, a combination of sunlight-stimulated production and loss via photo-induced oxidation and evaporation regulated the diurnal trends of DGM. Seasonal variations with elevated Hg fluxes and RHg concentrations in warm season were noticeable in the study area, which highlighted the combined effect of interrelationships between Hg species in water and environmental parameters. Hg fluxes exhibited much more significant correlations with RHg and THg concentrations and air temperature compared to DGM concentrations and solar radiation. The measured fluxes were significantly higher than those simulated using the water/air thin film Hg0 gradient model. Aside from the potential limitations of dynamic flux chamber method, this may also suggest the thin film gas exchange model is not capable of predicting water/air Hg flux under low wind speed conditions. Additionally, it is speculated that DGM concentrations might vary significantly in surface waters with depth, and measurements of DGM at a depth of 2-4 cm below the water surface probably underestimated the DGM concentration that should be taken into account in simulations of water/air flux using the thin film gas exchange model. An empirical model of water/air Hg flux was developed, and the simulated fluxes were compared well with measurements. The model yields a mean annual Hg emission of 3.2 ± 1.0 kg in the study area.

Fu, Xuewu; Feng, Xinbin; Guo, Yanna; Meng, Bo; Yin, Runsheng; Yao, Heng

2013-05-01

307

Ebselen blocks the quinolinic acid-induced production of thiobarbituric acid reactive species but does not prevent the behavioral alterations produced by intra-striatal quinolinic acid administration in the rat  

Microsoft Academic Search

Ebselen (EBS) is a seleno-organic compound with glutathione peroxidase-like activity which is neuroprotective in acute stroke ischemia. In this study, we investigated the effect of EBS on quinolinic acid (QA)-induced neurotoxicity. EBS inhibited QA-induced production of thiobarbituric acid reactive species (TBARS) by striatal homogenates in vitro with an IC50 of 1.85 ?M. Intra-striatal injection of QA (360 nmol) increased striatal

Janine I Rossato; Gilson Zeni; Carlos F Mello; Maribel A Rubin; João B. T Rocha

2002-01-01

308

Single spin asymmetries in charged kaon production from semi-inclusive deep inelastic scattering on a transversely polarized 3He target  

NASA Astrophysics Data System (ADS)

We report the first measurement of target single spin asymmetries of charged kaons produced in semi-inclusive deep inelastic scattering of electrons off a transversely polarized 3He target. Both the Collins and Sivers moments, which are related to the nucleon transversity and Sivers distributions, respectively, are extracted over the kinematic range of 0.1 production. While the Collins and Sivers moments for K+ are consistent with zero within the experimental uncertainties, both moments for K- favor negative values. The Sivers moments are compared to the theoretical prediction from a phenomenological fit to the world data. While the K+ Sivers moments are consistent with the prediction, the K- results differ from the prediction at the 2-sigma level.

Zhao, Y. X.; Wang, Y.; Allada, K.; Aniol, K.; Annand, J. R. M.; Averett, T.; Benmokhtar, F.; Bertozzi, W.; Bradshaw, P. C.; Bosted, P.; Camsonne, A.; Canan, M.; Cates, G. D.; Chen, C.; Chen, J.-P.; Chen, W.; Chirapatpimol, K.; Chudakov, E.; Cisbani, E.; Cornejo, J. C.; Cusanno, F.; Dalton, M. M.; Deconinck, W.; de Jager, C. W.; De Leo, R.; Deng, X.; Deur, A.; Ding, H.; Dolph, P. A. M.; Dutta, C.; Dutta, D.; El Fassi, L.; Frullani, S.; Gao, H.; Garibaldi, F.; Gaskell, D.; Gilad, S.; Gilman, R.; Glamazdin, O.; Golge, S.; Guo, L.; Hamilton, D.; Hansen, O.; Higinbotham, D. W.; Holmstrom, T.; Huang, J.; Huang, M.; Ibrahim, H. F.; Iodice, M.; Jiang, X.; Jin, G.; Jones, M. K.; Katich, J.; Kelleher, A.; Kim, W.; Kolarkar, A.; Korsch, W.; LeRose, J. J.; Li, X.; Li, Y.; Lindgren, R.; Liyanage, N.; Long, E.; Lu, H.-J.; Margaziotis, D. J.; Markowitz, P.; Marrone, S.; McNulty, D.; Meziani, Z.-E.; Michaels, R.; Moffit, B.; Muñoz Camacho, C.; Nanda, S.; Narayan, A.; Nelyubin, V.; Norum, B.; Oh, Y.; Osipenko, M.; Parno, D.; Peng, J.-C.; Phillips, S. K.; Posik, M.; Puckett, A. J. R.; Qian, X.; Qiang, Y.; Rakhman, A.; Ransome, R.; Riordan, S.; Saha, A.; Sawatzky, B.; Schulte, E.; Shahinyan, A.; Shabestari, M. H.; Širca, S.; Stepanyan, S.; Subedi, R.; Sulkosky, V.; Tang, L.-G.; Tobias, A.; Urciuoli, G. M.; Vilardi, I.; Wang, K.; Wojtsekhowski, B.; Yan, X.; Yao, H.; Ye, Y.; Ye, Z.; Yuan, L.; Zhan, X.; Zhang, Y.; Zhang, Y.-W.; Zhao, B.; Zheng, X.; Zhu, L.; Zhu, X.; Zong, X.; Jefferson Lab Hall A Collaboration

2014-11-01

309

Measurement of pretzelosity asymmetry of charged pion production in Semi-Inclusive Deep Inelastic Scattering on a polarized $^3$He target  

E-print Network

An experiment to measure single-spin asymmetries in semi-inclusive production of charged pions in deep-inelastic scattering on a transversely polarized $^3$He target was performed at Jefferson Lab in the kinematic region of $0.16

Y. Zhang; X. Qian; K. Allada; C. Dutta; J. Huang; J. Katich; Y. Wang; K. Aniol; J. R. M. Annand; T. Averett; F. Benmokhtar; W. Bertozzi; P. C. Bradshaw; P. Bosted; A. Camsonne; M. Canan; G. D. Cates; C. Chen; J. -P. Chen; W. Chen; K. Chirapatpimol; E. Chudakov; E. Cisbani; J. C. Cornejo; F. Cusanno; M. M. Dalton; W. Deconinck; C. W. de Jager; R. De Leo; X. Deng; A. Deur; H. Ding; P. A. M. Dolph; D. Dutta; L. El Fassi; S. Frullani; H. Gao; F. Garibaldi; D. Gaskell; S. Gilad; R. Gilman; O. Glamazdin; S. Golge; L. Guo; D. Hamilton; O. Hansen; D. W. Higinbotham; T. Holmstrom; M. Huang; H. F. Ibrahim; M. Iodice; X. Jiang; G. Jin; M. K. Jones; A. Kelleher; W. Kim; A. Kolarkar; W. Korsch; J. J. LeRose; X. Li; Y. Li; R. Lindgren; N. Liyanage; E. Long; H. -J. Lu; D. J. Margaziotis; P. Markowitz; S. Marrone; D. McNulty; Z. -E. Meziani; R. Michaels; B. Moffit; C. Muñoz Camacho; S. Nanda; A. Narayan; V. Nelyubin; B. Norum; Y. Oh; M. Osipenko; D. Parno; J. C. Peng; S. K. Phillips; M. Posik; A. J. R. Puckett; Y. Qiang; A. Rakhman; R. D. Ransome; S. Riordan; A. Saha; B. Sawatzky; E. Schulte; A. Shahinyan; M. H. Shabestari; S. Sirca; S. Stepanyan; R. Subedi; V. Sulkosky; L. -G. Tang; W. A. Tobias; G. M. Urciuoli; I. Vilardi; K. Wang; B. Wojtsekhowski; X. Yan; H. Yao; Y. Ye; Z. Ye; L. Yuan; X. Zhan; Y. -W. Zhang; B. Zhao; X. Zheng; L. Zhu; X. Zhu; X. Zong

2013-12-11

310

Single Spin Asymmetries in Charged Kaon Production from Semi-Inclusive Deep Inelastic Scattering on a Transversely Polarized $^3{\\rm{He}}$ Target  

E-print Network

We report the first measurement of target single spin asymmetries of charged kaons produced in semi-inclusive deep inelastic scattering of electrons off a transversely polarized $^3{\\rm{He}}$ target. Both the Collins and Sivers moments, which are related to the nucleon transversity and Sivers distributions, respectively, are extracted over the kinematic range of 0.1$<$$x_{bj}$$<$0.4 for $K^{+}$ and $K^{-}$ production. While the Collins and Sivers moments for $K^{+}$ are consistent with zero within the experimental uncertainties, both moments for $K^{-}$ favor negative values. The Sivers moments are compared to the theoretical prediction from a phenomenological fit to the world data. While the $K^{+}$ Sivers moments are consistent with the prediction, the $K^{-}$ results differ from the prediction at the 2-sigma level.

Zhao, Y X; Allada, K; Aniol, K; Annand, J R M; Averett, T; Benmokhtar, F; Bertozzi, W; Bradshaw, P C; Bosted, P; Camsonne, A; Canan, M; Cates, G D; Chen, C; Chen, J -P; Chen, W; Chirapatpimol, K; Chudakov, E; Cisbani, E; Cornejo, J C; Cusanno, F; Dalton, M M; Deconinck, W; de Jager, C W; De Leo, R; Deng, X; Deur, A; Ding, H; Dolph, P A M; Dutta, C; Dutta, D; Fassi, L El; Frullani, S; Gao, H; Garibaldi, F; Gaskell, D; Gilad, S; Gilman, R; Glamazdin, O; Golge, S; Guo, L; Hamilton, D; Hansen, O; Higinbotham, D W; Holmstrom, T; Huang, J; Huang, M; Ibrahim, H F; Iodice, M; Jiang, X; Jin, G; Jones, M K; Katich, J; Kelleher, A; Kim, W; Kolarkar, A; Korsch, W; LeRose, J J; Li, X; Li, Y; Lindgren, R; Liyanage, N; Long, E; Lu, H -J; Margaziotis, D J; Markowitz, P; Marrone, S; McNulty, D; Meziani, Z -E; Michaels, R; Moffit, B; Camacho, C Muñoz; Nanda, S; Narayan, A; Nelyubin, V; Norum, B; Oh, Y; Osipenko, M; Parno, D; Peng, J -C; Phillips, S K; Posik, M; Puckett, A J R; Qian, X; Qiang, Y; Rakhman, A; Ransome, R; Riordan, S; Saha, A; Sawatzky, B; Schulte, E; Shahinyan, A; Shabestari, M H; Širca, S; Stepanyan, S; Subedi, R; Sulkosky, V; Tang, L -G; Tobias, A; Urciuoli, G M; Vilardi, I; Wang, K; Wojtsekhowski, B; Yan, X; Yao, H; Ye, Y; Ye, Z; Yuan, L; Zhan, X; Zhang, Y; Zhang, Y -W; Zhao, B; Zheng, X; Zhu, L; Zhu, X; Zong, X

2014-01-01

311

Single Spin Asymmetries in Charged Kaon Production from Semi-Inclusive Deep Inelastic Scattering on a Transversely Polarized $^3{\\rm{He}}$ Target  

E-print Network

We report the first measurement of target single spin asymmetries of charged kaons produced in semi-inclusive deep inelastic scattering of electrons off a transversely polarized $^3{\\rm{He}}$ target. Both the Collins and Sivers moments, which are related to the nucleon transversity and Sivers distributions, respectively, are extracted over the kinematic range of 0.1$<$$x_{bj}$$<$0.4 for $K^{+}$ and $K^{-}$ production. While the Collins and Sivers moments for $K^{+}$ are consistent with zero within the experimental uncertainties, both moments for $K^{-}$ favor negative values. The Sivers moments are compared to the theoretical prediction from a phenomenological fit to the world data. While the $K^{+}$ Sivers moments are consistent with the prediction, the $K^{-}$ results differ from the prediction at the 2-sigma level.

Y. X. Zhao; Y. Wang; K. Allada; K. Aniol; J. R. M. Annand; T. Averett; F. Benmokhtar; W. Bertozzi; P. C. Bradshaw; P. Bosted; A. Camsonne; M. Canan; G. D. Cates; C. Chen; J. -P. Chen; W. Chen; K. Chirapatpimol; E. Chudakov; E. Cisbani; J. C. Cornejo; F. Cusanno; M. M. Dalton; W. Deconinck; C. W. de Jager; R. De Leo; X. Deng; A. Deur; H. Ding; P. A. M. Dolph; C. Dutta; D. Dutta; L. El Fassi; S. Frullani; H. Gao; F. Garibaldi; D. Gaskell; S. Gilad; R. Gilman; O. Glamazdin; S. Golge; L. Guo; D. Hamilton; O. Hansen; D. W. Higinbotham; T. Holmstrom; J. Huang; M. Huang; H. F Ibrahim; M. Iodice; X. Jiang; G. Jin; M. K. Jones; J. Katich; A. Kelleher; W. Kim; A. Kolarkar; W. Korsch; J. J. LeRose; X. Li; Y. Li; R. Lindgren; N. Liyanage; E. Long; H. -J. Lu; D. J. Margaziotis; P. Markowitz; S. Marrone; D. McNulty; Z. -E. Meziani; R. Michaels; B. Moffit; C. Muñoz Camacho; S. Nanda; A. Narayan; V. Nelyubin; B. Norum; Y. Oh; M. Osipenko; D. Parno; J. -C. Peng; S. K. Phillips; M. Posik; A. J. R. Puckett; X. Qian; Y. Qiang; A. Rakhman; R. Ransome; S. Riordan; A. Saha; B. Sawatzky; E. Schulte; A. Shahinyan; M. H. Shabestari; S. Širca; S. Stepanyan; R. Subedi; V. Sulkosky; L. -G. Tang; A. Tobias; G. M. Urciuoli; I. Vilardi; K. Wang; B. Wojtsekhowski; X. Yan; H. Yao; Y. Ye; Z. Ye; L. Yuan; X. Zhan; Y. Zhang; Y. -W. Zhang; B. Zhao; X. Zheng; L. Zhu; X. Zhu; X. Zong

2014-04-29

312

Computational chemistry of natural products: a comparison of the chemical reactivity of isonaringin calculated with the M06 family of density functionals.  

PubMed

The M06 family of density functionals has been assessed for the calculation of the molecular structure and properties of the Isonaringin flavonoid that can be an interesting material for dye-sensitized solar cells (DSSC). The chemical reactivity descriptors have been calculated through chemical reactivity theory within DFT (CR-DFT). The active sites for nucleophilic and electrophilic attacks have been chosen by relating them to the Fukui function indices and the dual descriptor f ((2))(r). A comparison between the descriptors calculated through vertical energy values and those arising from the Janak's theorem approximation have been performed in order to check for the validity of the last procedure. PMID:24992989

Glossman-Mitnik, Daniel

2014-07-01

313

Processing and characterization of reactions and products in reactive multilayer foils: Investigating the nickel/aluminum and copper oxide/aluminum systems  

NASA Astrophysics Data System (ADS)

Self-propagating reactions were studied in multilayer foils. These sputter-deposited microlaminates consist of alternating layers of two materials which mix and react exothermically. The heat generated by the reaction propagates the reaction through the foil. A thorough understanding of the thermodynamics and kinetics of these reactions, and the sequence of intermediate phase formation, is vital for engineering these foils for applications such as joining. Here, two reactive systems were investigated: nickel/aluminum (formation reaction) and copper oxide/aluminum (reduction-oxidation reaction). Reaction paths and kinetics were studied with differential scanning calorimetry, Auger depth-profiling, x-ray photoelectron spectroscopy, and energy-filtered transmission electron microscopy. In the Ni/Al foils, the metastable phase Al9Ni2 formed as the first phase in a series of Ni/Al multilayer foils, but it did not form in foils with a small bilayer period (12.5 nm) where the stable phase Al3Ni formed first. The heat of formation and Gibbs free energy for Al9Ni2 were both calculated to be -28 kJ/mole·atom, and the average activation energy for Al9Ni2's formation was calculated to be 1.58 eV. A nucleation model based on thermodynamics and diffusive intermixing is proposed to explain why Al9Ni2 forms before Al3Ni in most cases, but not in foils with small bilayers. CuOx/Al multilayers were successfully sputter-deposited. These thermite reactions self-propagate at 1 m/s and the heat released is -3.9 kJ/g. The CuOx deposited in the foils is non-stoichiometric Cu 4O3 (paramelaconite); the heat of formation and Gibbs free energy for Cu4O3 were calculated to be -453 kJ/mole and -279 kJ/mole, respectively. When these foils react in a differential thermal analyzer, the paramelaconite decomposes into CuO and Cu2O. The reaction then proceeds via two exotherms. First, an interfacial layer of Al2O3 grows to coalescence; second, this layer thickens and the final reaction products are Cu, Al2O3, and Cu 2O. A Modified Coffey Model was applied to help explain the calorimetry results. The first exotherm was assumed to be controlled by the two-dimensional, interface-limited growth of the Al2O3 layer, while the second exotherm was assumed to be controlled by one-dimensional growth of the Al2O3 and the reduction of Cu2O.

Blobaum, Kerri Jayne

2002-09-01

314

Dynamics of inelastic and reactive gas-surface collisions  

SciTech Connect

The dynamics of inelastic and reactive collisions in atomic beam-surface scattering are presented. The inelastic scattering of hyperthermal rare gaseous atoms from three alkali halide surfaces (LiF, NaCl, GI)was studied to understand mechanical energy transfer in unreactive systems. The dynamics of the chemical reaction in the scattering of H(D) atoms from the surfaces of LIF(001) and the basal plane of graphite were also studied.

Smoliar, L.A.

1995-04-01

315

Uric Acid-Induced C-Reactive Protein Expression: Implication on Cell Proliferation and Nitric Oxide Production of Human Vascular Cells  

Microsoft Academic Search

Recent experimental and human studies have shown that hyperuricemia is associated with hypertension, systemic inflam- mation, and cardiovascular disease mediated by endothelial dysfunction and pathologic vascular remodeling. Elevated levels of C-reactive protein (CRP) have emerged as one of the most powerful independent predictors of cardiovascular disease. In addition to being a marker of inflammation, recent evidence suggests that CRP may

Duk-Hee Kang; Sung-Kwang Park; In-Kyu Lee; Richard J. Johnson

2005-01-01

316

Controlling uranium reactivity March 18, 2008  

E-print Network

uranium research. In reality, uranium presents a wealth of possibilities for funda- mental chemistry. Many channel. The disparity in size of the reactive sites leads to the formation of different products when exerted by the colossal structure surrounding the reactive site caused a nitrogen atom to be inserted

Meyer, Karsten

317

Overview of progress in neutrino scattering measurements  

E-print Network

Recent progress in neutrino scattering experiments with few GeV neutrino beams is reviewed, focusing on new experimental input since the beginning of the NuInt workshop series in 2001. Progress in neutrino quasi-elastic scattering, resonance production, coherent pion production, scattering in the transition region between the resonance and deep inelastic regimes, and nuclear effects in neutrino-nucleus scattering, is discussed.

M. Sorel

2007-10-22

318

Inelastic {J}/{?} production in deep inelastic scattering from hydrogen and deuterium and the gluon distribution of free nucleons  

NASA Astrophysics Data System (ADS)

We present results on inelastic J/? production from muon interactions with hydrogen and deuterium at an incident muon energy of 280 GeV. The measured cross section ratio per nucleon for muon-induced {J}/{?} production in deuterium and hydrogen was found to be R(D 2/H 2) = 1.01±0.15. The colour singlet model is shown to provide a good description of the observed differential cross section apart from a normalisation factor. The comparison between the observed cross section and the colour singlet model prediction allows the extraction of the gluon structure function G( x) of the nucleon. The momentum fraction x of the nucleon carried by the gluon is measured in the range of x = [0.02, 0.30]. The normalised gluon distribution of free nucleons thus found can be parametrised as xG(x) = {1}/{2} (?+1) (1-x) ?, with?=5+-9( sta.) .

Allasia, D.; Amaudruz, P.; Arneodo, M.; Arvidson, A.; Badelek, B.; Baum, G.; Beaufays, J.; Bird, I. G.; Botje, M.; Broggini, C.; Brückner, W.; Brüll, A.; Burger, W. J.; Ciborowski, J.; Crittenden, R.; van Dantzig, R.; Döbbeling, H.; Domingo, J.; Drinkard, J.; Dzierba, A.; Engelien, H.; Ferrero, M. I.; Fluri, L.; Grafstrom, P.; Hagberg, E.; von Harrach, D.; van der Heijden, M.; Heusch, C.; Ingram, Q.; Jacholkowska, A.; Janson, K.; de Jong, M.; Kabu?, E. M.; Kaiser, R.; Ketel, T. J.; Klein, F.; Korzen, B.; Krüner, U.; Kullander, S.; Landgraf, U.; Lettenström, F.; Lindqvist, T.; Mallot, G. K.; Mariotti, C.; van Middelkoop, G.; Mizuno, Y.; Nassalski, J.; Nowotny, D.; Pavel, N.; Peschel, H.; Peroni, C.; Pietrzyk, U.; Povh, B.; Rieger, R.; Rith, K.; Röhrich, K.; Rondio, E.; Ropelewski, L.; Sandacz, A.; Scholz, C.; Schumacher, R.; Sennhausser, U.; Sever, F.; Shibata, T.-A.; Siebler, M.; Simon, A.; Staiano, A.; Taylor, G.; Treichel, M.; Vuilleumier, J. L.; Walcher, T.; Welch, K.; Windmolders, R.; New Muon Collaboration (NMC)

1991-04-01

319

Method For Reactivating Solid Catalysts Used For Alklation Reactions  

DOEpatents

A method for reactivating a solid alkylation catalyst is provided which can be performed within a reactor that contains the alkylation catalyst or outside the reactor. Effective catalyst reactivation is achieved whether the catalyst is completely deactivated or partially deactivated. A fluid reactivating agent is employed to dissolve catalyst fouling agents and also to react with such agents and carry away the reaction products. The deactivated catalyst is contacted with the fluid reactivating agent under pressure and temperature conditions such that the fluid reactivating agent is dense enough to effectively dissolve the fouling agents and any reaction products of the fouling agents and the reactivating agent. Useful pressures and temperatures for reactivation include near-critical, critical, and supercritical pressures and temperatures for the reactivating agent. The fluid reactivating agent can include, for example, a branched paraffin containing at least one tertiary carbon atom, or a compound that can be isomerized to a molecule containing at least one tertiary carbon atom.

Ginosar, Daniel M. (Idaho Falls, ID); Thompson, David N. (Idaho Falls, ID); Coates, Kyle (Shelley, ID); Zalewski, David J. (Proctorville, OH); Fox, Robert V. (Idaho Falls, ID)

2005-05-03

320

Measurement of the nu(mu) Charged Current pi+ Production to Quasi-elastic Scattering Cross Section  

SciTech Connect

Using high statistics samples of charged current interactions, MiniBooNE reports a model independent measurement of the single charged pion production to quasi-elastic cross section ratio on mineral oil without corrections for pion re-interactions in the target nucleus [1]. The result is provided as a function of neutrino energy in the range 0.4 GeV < E < 2.4 GeV with 11% precision in the region of highest statistics.

Nowak, Jaroslaw A.; /Louisiana State U.

2009-09-01

321

Compton Scattering  

NSDL National Science Digital Library

The purpose of this experiment is to verify the energy dependence of gamma radiation upon scattering angle and to compare the differential cross section obtained from the data with those calculated using the Klein-Nishina formula and classical theory.

2012-03-25

322

Scattering Theory  

Microsoft Academic Search

\\u000a In this chapter we discuss theoretical techniques and simulation methods for calculating the scattering of a coherent laser\\u000a field by one or more particles. Where possible, our treatment of Mie scattering theory uses simple linear algebra representation\\u000a of the concepts involved, with the mathematical details confined to appendices. In formulating this approach we have drawn\\u000a together results from a wide

Jonathan M. Taylor

323

3,3?,4,4?-Tetrachlorobiphenyl oxidation in fish, bird and reptile species: relationship to cytochrome P450 1A inactivation and reactive oxygen production  

Microsoft Academic Search

Previously we showed that the polychlorinated biphenyl 3,3?,4,4?-tetrachlorobiphenyl (TCB) caused a release of reactive oxygen species (ROS) from cytochrome P450 1A (CYP1A) of the fish scup (Stenotomus chrysops), and from rat and human CYP1A1. This was linked to a TCB- and NADPH-dependent oxidative inactivation of the enzyme, which in scup and rat was inversely related to the rates of TCB

Jennifer J Schlezinger; Jennifer Keller; Lori A Verbrugge; John J Stegeman

2000-01-01

324

Induction of Spermidine\\/Spermine N 1Acetyltransferase in Human Cancer Cells in Response to Increased Production of Reactive Oxygen Species  

Microsoft Academic Search

Reactive oxygen species (ROS) are involved in a number of disease states where they are believed to be responsible for cellular damage. In this study we examined the effect of ROS generation on polyamine catabolism. Treatment of human breast cancer cells with either H2O2 or hyperoxia increased the activity of spermidine\\/spermine N1-acetyltransferase (SSAT). These increases occurred before any significant signs

Shalu Chopra; Heather M Wallace

1998-01-01

325

Measurement of beauty and charm production in deep inelastic scattering at HERA and measurement of the beauty-quark mass  

E-print Network

The production of beauty and charm quarks in ep interactions has been studied with the ZEUS detector at HERA for exchanged four-momentum squared 5 energy and pseudorapidity were measured and compared with next-to-leading-order QCD calculations. The beauty and charm contributions to the proton structure functions were extracted from the double-differential cross section as a function of x and Q^2. The running beauty-quark mass, m_b at the scale m_b, was determined from a QCD fit at next-to-leading order to HERA data for the first time and found to be 4.07 \\pm 0.14 (fit} ^{+0.01}_{-0.07} (mod.) ^{+0.05}_{-0.00} (param.) ^{+0.08}_{-0.05} (theo) GeV.

ZEUS collaboration; H. Abramowicz; I. Abt; L. Adamczyk; M. Adamus; R. Aggarwal; S. Antonelli; O. Arslan; V. Aushev; Y. Aushev; O. Bachynska; A. N. Barakbaev; N. Bartosik; O. Behnke; J. Behr; U. Behrens; A. Bertolin; S. Bhadra; I. Bloch; V. Bokhonov; E. G. Boos; K. Borras; I. Brock; R. Brugnera; A. Bruni; B. Brzozowska; P. J. Bussey; A. Caldwell; M. Capua; C. D. Catterall; J. Chwastowski; J. Ciborowski; R. Ciesielski; A. M. Cooper-Sarkar; M. Corradi; F. Corriveau; G. D'Agostini; R. K. Dementiev; R. C. E. Devenish; G. Dolinska; V. Drugakov; S. Dusini; J. Ferrando; J. Figiel; B. Foster; G. Gach; A. Garfagnini; A. Geiser; A. Gizhko; L. K. Gladilin; O. Gogota; Yu. A. Golubkov; J. Grebenyuk; I. Gregor; G. Grzelak; O. Gueta; M. Guzik; W. Hain; G. Hartner; D. Hochman; R. Hori; Z. A. Ibrahim; Y. Iga; M. Ishitsuka; A. Iudin; F. Januschek; I. Kadenko; S. Kananov; T. Kanno; U. Karshon; M. Kaur; P. Kaur; L. A. Khein; D. Kisielewska; R. Klanner; U. Klein; N. Kondrashova; O. Kononenko; Ie. Korol; I. A. Korzhavina; A. Kota?ski; U. Kötz; N. Kovalchuk; H. Kowalski; O. Kuprash; M. Kuze; B. B. Levchenko; A. Levy; V. Libov; S. Limentani; M. Lisovyi; E. Lobodzinska; W. Lohmann; B. Löhr; E. Lohrmann; A. Longhin; D. Lontkovskyi; O. Yu. Lukina; J. Maeda; I. Makarenko; J. Malka; J. F. Martin; S. Mergelmeyer; F. Mohamad Idris; K. Mujkic; V. Myronenko; K. Nagano; A. Nigro; T. Nobe; D. Notz; R. J. Nowak; K. Olkiewicz; Yu. Onishchuk; E. Paul; W. Perla?ski; H. Perrey; N. S. Pokrovskiy; A. S. Proskuryakov; M. Przybycie?; A. Raval; P. Roloff; I. Rubinsky; M. Ruspa; V. Samojlov; D. H. Saxon; M. Schioppa; W. B. Schmidke; U. Schneekloth; T. Schörner-Sadenius; J. Schwartz; L. M. Shcheglova; R. Shehzadi; R. Shevchenko; O. Shkola; I. Singh; I. O. Skillicorn; W. S?omi?ski; V. Sola; A. Solano; A. Spiridonov; L. Stanco; N. Stefaniuk; A. Stern; T. P. Stewart; P. Stopa; J. Sztuk-Dambietz; D. Szuba; J. Szuba; E. Tassi; T. Temiraliev; K. Tokushuku; J. Tomaszewska; A. Trofymov; V. Trusov; T. Tsurugai; M. Turcato; O. Turkot; T. Tymieniecka; A. Verbytskyi; O. Viazlo; R. Walczak; W. A. T. Wan Abdullah; K. Wichmann; M. Wing; G. Wolf; S. Yamada; Y. Yamazaki; N. Zakharchuk; A. F. ?arnecki; L. Zawiejski; O. Zenaiev; B. O. Zhautykov; N. Zhmak; D. S. Zotkin

2014-05-27

326

System for reactivating catalysts  

DOEpatents

A method of reactivating a catalyst, such as a solid catalyst or a liquid catalyst is provided. The method comprises providing a catalyst that is at least partially deactivated by fouling agents. The catalyst is contacted with a fluid reactivating agent that is at or above a critical point of the fluid reactivating agent and is of sufficient density to dissolve impurities. The fluid reactivating agent reacts with at least one fouling agent, releasing the at least one fouling agent from the catalyst. The at least one fouling agent becomes dissolved in the fluid reactivating agent and is subsequently separated or removed from the fluid reactivating agent so that the fluid reactivating agent may be reused. A system for reactivating a catalyst is also disclosed.

Ginosar, Daniel M. (Idaho Falls, ID); Thompson, David N. (Idaho Falls, ID); Anderson, Raymond P. (Idaho Falls, ID)

2010-03-02

327

Reactive Arthritis Treatment  

MedlinePLUS

Reactive Arthritis (ReA): Quick Links Overview >>> Symptoms >>> Diagnosis >>> Treatment >>> Medication >>> Doctor Q&A From Spondylitis Plus >>> REACTIVE ARTHRITIS Overview Seeing a rheumatologist is essential to beginning ...

328

Measurement of beauty and charm production in deep inelastic scattering at HERA and measurement of the beauty-quark mass  

E-print Network

The production of beauty and charm quarks in ep interactions has been studied with the ZEUS detector at HERA for exchanged four-momentum squared 5 < Q^2 < 1000 GeV^2 using an integrated luminosity of 354 pb^{-1}. The beauty and charm content in events with at least one jet have been extracted using the invariant mass of charged tracks associated with secondary vertices and the decay-length significance of these vertices. Differential cross sections as a function of Q^2, Bjorken x, jet transverse energy and pseudorapidity were measured and compared with next-to-leading-order QCD calculations. The beauty and charm contributions to the proton structure functions were extracted from the double-differential cross section as a function of x and Q^2. The running beauty-quark mass, m_b at the scale m_b, was determined from a QCD fit at next-to-leading order to HERA data for the first time and found to be 4.07 \\pm 0.14 (fit} ^{+0.01}_{-0.07} (mod.) ^{+0.05}_{-0.00} (param.) ^{+0.08}_{-0.05} (theo) GeV.

ZEUS collaboration; H. Abramowicz; I. Abt; L. Adamczyk; M. Adamus; R. Aggarwal; S. Antonelli; O. Arslan; V. Aushev; Y. Aushev; O. Bachynska; A. N. Barakbaev; N. Bartosik; O. Behnke; J. Behr; U. Behrens; A. Bertolin; S. Bhadra; I. Bloch; V. Bokhonov; E. G. Boos; K. Borras; I. Brock; R. Brugnera; A. Bruni; B. Brzozowska; P. J. Bussey; A. Caldwell; M. Capua; C. D. Catterall; J. Chwastowski; J. Ciborowski; R. Ciesielski; A. M. Cooper-Sarkar; M. Corradi; F. Corriveau; G. D'Agostini; R. K. Dementiev; R. C. E. Devenish; G. Dolinska; V. Drugakov; S. Dusini; J. Ferrando; J. Figiel; B. Foster; G. Gach; A. Garfagnini; A. Geiser; A. Gizhko; L. K. Gladilin; O. Gogota; Yu. A. Golubkov; J. Grebenyuk; I. Gregor; G. Grzelak; O. Gueta; M. Guzik; W. Hain; G. Hartner; D. Hochman; R. Hori; Z. A. Ibrahim; Y. Iga; M. Ishitsuka; A. Iudin; F. Januschek; I. Kadenko; S. Kananov; T. Kanno; U. Karshon; M. Kaur; P. Kaur; L. A. Khein; D. Kisielewska; R. Klanner; U. Klein; N. Kondrashova; O. Kononenko; Ie. Korol; I. A. Korzhavina; A. Kota?ski; U. Kötz; N. Kovalchuk; H. Kowalski; O. Kuprash; M. Kuze; B. B. Levchenko; A. Levy; V. Libov; S. Limentani; M. Lisovyi; E. Lobodzinska; W. Lohmann; B. Löhr; E. Lohrmann; A. Longhin; D. Lontkovskyi; O. Yu. Lukina; J. Maeda; I. Makarenko; J. Malka; J. F. Martin; S. Mergelmeyer; F. Mohamad Idris; K. Mujkic; V. Myronenko; K. Nagano; A. Nigro; T. Nobe; D. Notz; R. J. Nowak; K. Olkiewicz; Yu. Onishchuk; E. Paul; W. Perla?ski; H. Perrey; N. S. Pokrovskiy; A. S. Proskuryakov; M. Przybycie?; A. Raval; P. Roloff; I. Rubinsky; M. Ruspa; V. Samojlov; D. H. Saxon; M. Schioppa; W. B. Schmidke; U. Schneekloth; T. Schörner-Sadenius; J. Schwartz; L. M. Shcheglova; R. Shehzadi; R. Shevchenko; O. Shkola; I. Singh; I. O. Skillicorn; W. S?omi?ski; V. Sola; A. Solano; A. Spiridonov; L. Stanco; N. Stefaniuk; A. Stern; T. P. Stewart; P. Stopa; J. Sztuk-Dambietz; D. Szuba; J. Szuba; E. Tassi; T. Temiraliev; K. Tokushuku; J. Tomaszewska; A. Trofymov; V. Trusov; T. Tsurugai; M. Turcato; O. Turkot; T. Tymieniecka; A. Verbytskyi; O. Viazlo; R. Walczak; W. A. T. Wan Abdullah; K. Wichmann; M. Wing; G. Wolf; S. Yamada; Y. Yamazaki; N. Zakharchuk; A. F. ?arnecki; L. Zawiejski; O. Zenaiev; B. O. Zhautykov; N. Zhmak; D. S. Zotkin

2014-05-27

329

Measurement of beauty and charm production in deep inelastic scattering at HERA and measurement of the beauty-quark mass  

NASA Astrophysics Data System (ADS)

The production of beauty and charm quarks in ep interactions has been studied with the ZEUS detector at HERA for exchanged four-momentum squared 5 < Q 2 < 1000 GeV2 using an integrated luminosity of 354 pb-1. The beauty and charm content in events with at least one jet have been extracted using the invariant mass of charged tracks associated with secondary vertices and the decay-length significance of these vertices. Differential cross sections as a function of Q 2, Bjorken x, jet trans- verse energy and pseudorapidity were measured and compared with next-to-leading-order QCD calculations. The beauty and charm contributions to the proton structure functions were extracted from the double-differential cross section as a function of x and Q 2. The running beauty-quark mass, m b at the scale m b , was determined from a QCD fit at next-to-leading order to HERA data for the first time and found to be m b ( m b ) = 4.07 ± 0.14 (fit){-/0.07 + 0.01}(mod.){-/0.00 + 0.05}(param.){-/0.05 + 0.08}(theo.) GeV.

Abramowicz, H.; Abt, I.; Adamczyk, L.; Adamus, M.; Aggarwal, R.; Antonelli, S.; Arslan, O.; Aushev, V.; Aushev, Y.; Bachynska, O.; Barakbaev, A. N.; Bartosik, N.; Behnke, O.; Behr, J.; Behrens, U.; Bertolin, A.; Bhadra, S.; Bloch, I.; Bokhonov, V.; Boos, E. G.; Borras, K.; Brock, I.; Brugnera, R.; Bruni, A.; Brzozowska, B.; Bussey, P. J.; Caldwell, A.; Capua, M.; Catterall, C. D.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cooper-Sarkar, A. M.; Corradi, M.; Corriveau, F.; D'Agostini, G.; Dementiev, R. K.; Devenish, R. C. E.; Dolinska, G.; Drugakov, V.; Dusini, S.; Ferrando, J.; Figiel, J.; Foster, B.; Gach, G.; Garfagnini, A.; Geiser, A.; Gizhko, A.; Gladilin, L. K.; Gogota, O.; Golubkov, Yu. A.; Grebenyuk, J.; Gregor, I.; Grzelak, G.; Gueta, O.; Guzik, M.; Hain, W.; Hartner, G.; Hochman, D.; Hori, R.; Ibrahim, Z. A.; Iga, Y.; Ishitsuka, M.; Iudin, A.; Januschek, F.; Kadenko, I.; Kananov, S.; Kanno, T.; Karshon, U.; Kaur, M.; Kaur, P.; Khein, L. A.; Kisielewska, D.; Klanner, R.; Klein, U.; Kondrashova, N.; Kononenko, O.; Korol, Ie.; Korzhavina, I. A.; Kotanski, A.; Kötz, U.; Kovalchuk, N.; Kowalski, H.; Kuprash, O.; Kuze, M.; Levchenko, B. B.; Levy, A.; Libov, V.; Limentani, S.; Lisovyi, M.; Lobodzinska, E.; Lohmann, W.; Löhr, B.; Lohrmann, E.; Longhin, A.; Lontkovskyi, D.; Lukina, O. Yu.; Maeda, J.; Makarenko, I.; Malka, J.; Martin, J. F.; Mergelmeyer, S.; Mohamad Idris, F.; Mujkic, K.; Myronenko, V.; Nagano, K.; Nigro, A.; Nobe, T.; Notz, D.; Nowak, R. J.; Olkiewicz, K.; Onishchuk, Yu.; Paul, E.; Perlanski, W.; Perrey, H.; Pokrovskiy, N. S.; Proskuryakov, A. S.; Przybycien, M.; Raval, A.; Roloff, P.; Rubinsky, I.; Ruspa, M.; Samojlov, V.; Saxon, D. H.; Schioppa, M.; Schmidke, W. B.; Schneekloth, U.; Schörner-Sadenius, T.; Schwartz, J.; Shcheglova, L. M.; Shehzadi, R.; Shevchenko, R.; Shkola, O.; Singh, I.; Skillicorn, I. O.; Slominski, W.; Sola, V.; Solano, A.; Spiridonov, A.; Stanco, L.; Stefaniuk, N.; Stern, A.; Stewart, T. P.; Stopa, P.; Sztuk-Dambietz, J.; Szuba, D.; Szuba, J.; Tassi, E.; Temiraliev, T.; Tokushuku, K.; Tomaszewska, J.; Trofymov, A.; Trusov, V.; Tsurugai, T.; Turcato, M.; Turkot, O.; Tymieniecka, T.; Verbytskyi, A.; Viazlo, O.; Walczak, R.; Wan Abdullah, W. A. T.; Wichmann, K.; Wing, M.; Wolf, G.; Yamada, S.; Yamazaki, Y.; Zakharchuk, N.; ?arnecki, A. F.; Zawiejski, L.; Zenaiev, O.; Zhautykov, B. O.; Zhmak, N.; Zotkin, D. S.

2014-09-01

330

Production of reactive oxygen (H2O2) and nitrogen (NO) intermediates and tnf-? in mice genetically selected for high (H) and low (L) antibody response and experimentally infected with Leptospira serovar pomona  

PubMed Central

The aim of the present study was to evaluate the activity of macrophages, and the production of TNF-? and antibodies against experimental infection by Leptospira serovar Pomona in mice genetically selected for High (H) or Low (L) humoral immune response. To evaluate macrophagic activity, peritoneal and splenic lavages were performed for determination of oxygen (H2O2) and nitrogen (NO) intermediates. The production of the tumor necrosis factor (TNF-?) was investigated through bioassays in serum and homogenates of splenic and hepatic cells of control and infected animals, as was as specific antibodies production. The immune response against serovar Pomona in those lines, was characterized by high antibody production, especially in later periods of the infectious process, whereas values of bacterial recovery in culture medium were lower. The production of reactives oxygen and nitrogen intermediate, also helped to eliminate Leptospira Pomona in both lines; H2O2 production an important factor in HIV-A, as well as NO production in LIV-A, especially in later post-inoculation periods. The same was detected for TNF-?. Results suggest that such lines could be an important model to investigate the pathogenesis and the immune response of animals against the several Leptospira serovars. PMID:24031688

Haanwinckel, Maria Cristina Santos; de Oliveira, Silvio Luis

2011-01-01

331

Multi-year climatology of Mediterranean aerosol absorption optical depth and single scattering albedo products from ground-based and satellite remote sensing  

NASA Astrophysics Data System (ADS)

This study presents a multi-year climatology of aerosol absorption properties obtained over the Mediterranean from ground-based AERONET and satellite remote sensing observations including Multi-angle Imaging SpectroRadiometer (MISR, 2000-2011), Ozone Monitoring Instrument (OMI, 2004-2010), and MODerate resolution Imaging Spectroradiometer (MODIS, 2005-2011) spaceborne sensors. Our analysis is focused on the aerosol absorption optical depth (AAOD) and single scattering albedo (SSA). Sun-photometer observations obtained over more than 20 Mediterranean stations providing long time series (>2.5 yr) of level 2 products show that values of AAOD (at 440 nm) vary between 0.024 and 0.050 for urban sites and between 0.040 and 0.055 for sites under important influence of desert dust. Analysis shows that over the Mediterranean, urban-industrial aerosol appears "moderately" absorbing, with values of SSA close to ~ 0.94-0.95 (at 440 nm) in most cases except over Rome and Athens, where aerosol appears more absorbing (SSA ~ 0.89-0.90). The aerosol absorption Angström exponent (AAE) between 440 and 870 nm is found to be larger than 1 for most sites over the Mediterranean, as a result of mineral dust (iron) and/or brown carbon producing the observed absorption. AERONET Level 2 sunphotometer products (that correspond to AOD > 0.4) indicate the existence of a longitudinal gradient, with higher average values over the eastern basin (AAEEast = 1.48, AAEWest = 1.27) due to the desert dust influence. A more detailed analysis of AERONET data including level 1.5 products (corresponding to AOD down to 0.2) also shows that organic absorbing aerosols significantly affect some Mediterranean sites. Finally, an analysis of the regional variability in SSA is attempted using OMI, MISR and MODIS Deep Blue satellite products with a focus on spring and summer seasons which show the maximum aerosol load. The OMI and MODIS data show an absorbing region (SSA ~0.90 at 470-500 nm) over Northeast Africa that does not appear in the MISR retrievals. In contrast, MISR seems to observe the East-West SSA gradient during summer, as also detected by AERONET. Also, the analysis of satellite-derived SSA products indicates that the aerosol over the Mediterranean Sea appears less absorbing during spring than summer. However, the uncertainty associated with satellite SSA does not allow quantitative conclusions.

Mallet, Marc; Dubovik, Oleg; Nabat, Pierre; Kahn, Ralph; Sciare, Jean; Paronis, Dimitris; Somot, Samuel; Léon, Jean-François; Dulac, François

2013-04-01

332

Participation in reactive power market considering generator aging  

Microsoft Academic Search

As one of the most important ancillary services, reactive power production plays a crucial rule in power system operation, reliability and security. Because of the opportunity costs in providing reactive power, producers are under great pressure to provide VAr support. In this paper, a new challenge on the reactive capability curves (RCC) of the synchronous generator is discussed. The RCC

I. Niazy; J. Ebadi; S. Sabzevari; A. Niazy; H. Mortazavi; H. R. Poursoltani

2010-01-01

333

Reactivating personal memory 1 RUNNING HEAD: Reactivating personal memory  

E-print Network

Reactivating personal memory 1 RUNNING HEAD: Reactivating personal memory Modifying memory: Selectively enhancing and updating personal memories for a museum; Reactivating personal memory 2 Abstract Memory can be modified when reactivated

Schacter, Daniel

334

The composition dependence of the photochemical reactivity of strontium barium titanate  

NASA Astrophysics Data System (ADS)

The efficiency of particulate water photolysis catalysts is impractically low due to the recombination of intermediate species and charge carriers. The back reaction can occur easily if the oxidation and reduction sites on the surface of the catalyst are not far enough apart. It is hypothesized that it will be possible to increase the separation of the sites of the two half reactions and reduce the recombination of photogenerated charge carriers by using a ferroelectric material with permanent internal dipolar fields. This separation of the reaction sites may significantly increase the efficiency of the process. The present work compares the photochemical reactivities of ferroelectric and nonferroelectric materials (SrxBa1-xTiO 3, 0.0? x ?1.0) with similar composition and structure. The reactivities are compared by measuring the color change of methylene blue dye after the aqueous dye solution reacts on the surface of ceramic sample pellets as a result of exposure to UV light. The reactivities are also compared by measuring the amount of silver that is formed when an aqueous AgNO3 solution photochemically reacts on the surface. The change in the color of the dye is measured by diffuse reflectance spectroscopy and absorbance measurements. The amount of silver is measured by atomic force microscopy. The photochemical reactivity of SrxBa1-xTiO3 shows a local maximum at the composition of the ferroelectric to non-ferroelectric transition. Also, the reactivities decrease as BaTiO3 and SrTiO3 become less pure. The dominant factors causing this trend in reactivities of SrxBa1-xTiO3 are the dielectric constant and alloy scattering. It is found that higher values of the dielectric constant increase the photochemical reactivity by enlarging the space charge region. The increase in alloy scattering in SrxBa1-xTiO 3 solid solutions as x increases from zero or decreases from 1, has adverse effect on reactivity. There are other factors such as ferroelectric polarization, relative band edge positions and pH of the solution that can influence the reactivity. However, these factors are not significant in determining the composition dependence of the photochemical reactivity of SrxBa 1-xTiO3. The comparison of the surfaces of SrxBa 1-xTiO3 samples imaged by AFM after reaction (with silver nitrate) also showed that the mode of reaction gradually changes from spatially selective reactivity for BaTiO3 to spatially uniform reactivity for SrTiO3. The spatially selective reactivity disappears completely when x in SrxBa1-xTiO3 is greater than or equal to 0.28. The mechanism of the photochemical reaction of methylene blue dye on SrxBa1-xTiO3 was also studied. It is found that the dye reacts by a mechanism similar to that of silver. The methylene blue dye and silver reduce on the surfaces of positively charged domains and the reduced reaction products remain at the reduction reaction site. Extensions of this research would be to experimentally determine the band edges and defect concentrations in SrxBa1-xTiO 3 to get a better understanding of their influence on photochemical reactivity. Since the long term goal of this research is to find a efficient particulate catalyst for photocatalysis of water, the next step in this research is to carry out the photocatalysis of water using SrxBa1-x TiO3 powders. The effect of catalyst particle size should also be analyzed.

Bhardwaj, Abhilasha

335

Spirafolide from bay leaf ( Laurus nobilis ) prevents dopamine-induced apoptosis by decreasing reactive oxygen species production in human neuroblastoma SH-SY5Y cells  

Microsoft Academic Search

Reactive oxygen species (ROS) are important mediators in many neurodegenerative diseases including Alzheimer’s disease and\\u000a Parkinson’s disease. This study tested the neuroprotective effects of spirafolide, a compound purified from the leaves of\\u000a Laurus nobilis L. (Lauraceae), against dopamine (DA)-induced apoptosis in human neuroblastoma SH-SY5Y cells. Following a 24-h exposure of\\u000a cells to DA (final conc., 0.6 mM), we observed a

Ahrom Ham; Bora Kim; Uk Koo; Kung-Woo Nam; Sung-Jin Lee; Kyeong Ho Kim; Jongheon Shin; Woongchon Mar

2010-01-01

336

PHOTOCHEMICAL PRODUCTION OF REACTIVE OXYGEN SPECIES BY CONSTITUENTS OF COLORED DISSOLVED ORGANIC MATTER AND COASTAL RIVER WATERS IN THE SOUTHEASTERN UNITED STATES  

EPA Science Inventory

Using a previously developed method to measure OH production, formation rates were obtained for several water systems. Employing an amino-nitroxide probe and DMSO, an action spectrum for the product consistent with the production of OH by quinone moieties within humic material...

337

Column Studies on Reactive Mixing  

NASA Astrophysics Data System (ADS)

Reactive mixing of solutes in porous media has gained increasing interest since the beginning of the last decade. A better understanding of mixing in reactive transport is necessary to predict effectively groundwater remediation processes such as bioremediation and natural attenuation, as they may be controlled by mixing of the reacting compounds. It has been shown that classical macrodispersion concepts are not applicable to predict the actual mixing of compounds in heterogeneous media. Cirpka and Kitanidis (2000) suggested to quantify solute dilution by the second central moments of conservative breakthrough curves obtained at single points. From this quantity, it should be possible to predict reaction rates of non-sorbing reactants. The approach requires point measurements of a conservative tracer and reaction products. In the present study, we conduct experiments on mixing-controlled reactive transport in a one-dimensional water-saturated sand column. We use Fluorescein as tracer. Fluorescence intensity is measured directly within the sand filling by fiber-optic probes with a measurement volume of a few microliter. In the reactive tracer tests, an acidic solution containing the tracer is replaced by an alkaline solution without tracer. As fluorescence of Fluorescein is suppressed at low pH, fluorescence occurs only in the zone where the two solutions mix. To prevent sorption of Fluorescein at low pH, we add a non-ionic surfactant to both solutions. Conservative tracer experiments yield the mixing ratio of the two solutions at each point and time. With the mixing ratio, a titration curve of the two solutions and the relative fluorescence intensity as a function of pH, we can predict the reactive breakthrough curves for each probe. The zeroth moment of the predicted and measured reactive breakthrough curves differ by about 10%. The experimental method is also used in experiments in a large-scale sandbox with heterogeneous filling.

Jose, S. C.; Cirpka, O. A.

2003-04-01

338

Atmospheric Optics Scattering  

E-print Network

Atmospheric Optics Scattering: · Blue Sky (and polarized sky) [Rayleigh scattering] · Red Sunset [Rayleigh scattering] · Blue Haze [Rayleigh scattering] · Brown Smog [Mie scattering] · Blue (or other strange colored) Sun [Mie scattering] · White Clouds [geometric scattering] · Hazy (white) Sky [geometric

Hart, Gus

339

Conventional versus single-ladder-splitting contributions to double parton scattering production of two quarkonia, two Higgs bosons, and cc xAFcc xAF  

NASA Astrophysics Data System (ADS)

The double parton distributions (dPDF), both conventional (i.e. double ladder) and those corresponding to 1?2 ladder splitting, are calculated and compared for different two-parton combinations. The conventional and splitting dPDFs have very similar shape in x1 and x2. We make a first quantitative evaluation of the single-ladder-splitting contribution to double parton scattering (DPS) production of two S- or P-wave quarkonia, two Higgs bosons and cc ¯cc ¯. The ratio of the single-ladder-splitting to conventional (i.e. double ladder against double ladder) contributions is discussed as a function of center-of-mass energy, mass of the produced system and other kinematical variables. Using a simple model for the dependence of the conventional two-parton distribution on transverse parton separation (Gaussian and independent of xi and scales), we find that the single-ladder-splitting (or 2v1) contribution is as big as the conventional (or 2v2) contribution discussed in recent years in the literature. In many experimental studies of DPS, one extracts the quantity 1/?eff=?DPS/(?SPS ,1?SPS,2), with ?SPS ,1 and ?SPS ,2 being the single scattering cross sections for the two subprocesses in the DPS process. Many past phenomenological studies of DPS have only considered the conventional contribution and have obtained values a factor of ˜2 too small for 1/?eff. Our analysis shows that it is important also to consider the ladder-splitting mechanism, and that this might resolve the discrepancy (this was also pointed out in a recent study by Blok et al.). The differential distributions in rapidity and transverse momenta calculated for conventional and single-ladder-splitting DPS processes are however very similar which causes their experimental separation to be rather difficult, if not impossible. The direct consequence of the existence of the two components (conventional and splitting) is the energy and process dependence of the empirical parameter ?eff. This is illustrated in our paper for the considered processes.

Gaunt, Jonathan R.; Maciu?a, Rafa?; Szczurek, Antoni

2014-09-01

340

Enhanced Oxidative Reactivity for Anthracite Coal via a Reactive Ball Milling Pretreatment Step  

SciTech Connect

Reactive ball milling in a cyclohexene solvent significantly increases the oxidative reactivity of an anthracite coal, due to the combined effects of particle size reduction, metal introduction, introduction of volatile matter, and changes in carbon structure. Metals introduced during milling can be easily removed via a subsequent demineralization process, and the increased reactivity is retained. Solvent addition alters the morphological changes that occur during pyrolysis and leads to a char with significantly increased reactivity. When the solvent is omitted, similar effects are seen for the milled product, but a significant fraction of the char is resistant to oxidation. 33 refs., 3 figs., 1 tab.

Angela D. Lueking; Apurba Sakti; Dania Alvarez-Fonseca; Nichole Wonderling [Pennsylvania State University, PA (United States). Department of Energy and Mineral Engineering

2009-09-15

341

PLÉIADES: Responsiveness, Flexibility, Reactivity  

NASA Astrophysics Data System (ADS)

By the end of 2011, Astrium GEO-Information Services launched Pléiades 1, the first of two identical optical imaging satellites that will be operated on a phased orbit. This satellite system, designed by the French Space Agency, CNES, based upon French Defense specifications, will provide 50-cm products in record time. The overall aim of this paper is to describe the benefits of the innovative features of Pléiades 1 and its operations, so as to assess their combined potential in emergency situations, crisis recovery, regular monitoring or large area mapping. Specific care will be brought to describe the reactivity enabled by the system. Based on real-life examples, the paper will lead the analysis on the two main components of the system. On the one hand, the space segment will be presented through the following characteristics: revisit capacity, agility, acquisition capacity and acquisition scenarios (target, single-pass mosaics, stereo, tristereo, linear monitoring, persistent surveillance). On the other hand, the flexibility of the ground segment will be assessed. The benefits of multiple tasking plans per day, direct tasking capacity, automated processing and on-line ordering and delivering will be illustrated, tested and qualified for applications requiring a high level of responsiveness and reactivity. The presentation will end with a summary of the benefits of the space segment features and the flexibility of the ground segment, fine-tuned to answer both military and civilian / commercial needs. The analysis will be extended in the perspective of the second Pléiades' launch, highlighting the advantages of having two satellites operating on a phased orbit, affording a daily revisit anywhere on Earth, with very high resolution.

Gabriel-Robez, C.; Lees, R.; Bernard, M.

2012-08-01

342

Retinal ganglion cell death is triggered by paraptosis via reactive oxygen species production: a brief literature review presenting a novel hypothesis in glaucoma pathology.  

PubMed

Accumulative evidence has indicated that apoptosis is the common pathway for retinal ganglion cell (RGC) death and that autophagy promotes survival of RGCs in glaucoma. In the present review, it was hypothesized that the progressive death of RGCs in glaucoma involves another novel non?apoptotic programmed cell death, known as 'paraptosis', in the early stages of glaucoma. Paraptosis may be accompanied by apoptosis and/or autophagy in the moderate and severe stages. The secondary hypothesis suggests that paraptosis in glaucomatous RGCs may be triggered by damage to cellular mitochondria, and is associated with mitochondria-derived reactive oxygen species (ROS). Our preliminary laboratory studies, using transmission electron microscopy, provided evidence that supports the primary hypothesis. The secondary hypothesis is currently under investigation. These two hypotheses provide a novel way to investigate the mechanisms of cell death in glaucomatous RGCs and targeting paraptosis may be a promising strategy for RGC-protecting drug discovery. PMID:24969312

Wang, Yao; Xu, Kun; Zhang, Hongbing; Zhao, Junhong; Zhu, Xiuping; Wang, Yangzheng; Wu, Renyi

2014-09-01

343

Spirafolide from bay leaf (Laurus nobilis) prevents dopamine-induced apoptosis by decreasing reactive oxygen species production in human neuroblastoma SH-SY5Y cells.  

PubMed

Reactive oxygen species (ROS) are important mediators in many neurodegenerative diseases including Alzheimer's disease and Parkinson's disease. This study tested the neuroprotective effects of spirafolide, a compound purified from the leaves of Laurus nobilis L. (Lauraceae), against dopamine (DA)-induced apoptosis in human neuroblastoma SH-SY5Y cells. Following a 24-h exposure of cells to DA (final conc., 0.6 mM), we observed a marked increase in apoptosis, increased generation of ROS and decreased cell viability. Pretreatment of the cells for 24 h with spirafolide (0.4, 2, and 10 ?M) before exposure to DA notably increased cell survival (p < 0.01) and lowered intracellular ROS levels (p < 0.01). These results indicate that spirafolide has neuroprotective effects against DA toxicity. These effects may contribute to the treatment of neurodegenerative diseases. PMID:21191760

Ham, Ahrom; Kim, Bora; Koo, Uk; Nam, Kung-Woo; Lee, Sung-Jin; Kim, Kyeong Ho; Shin, Jongheon; Mar, Woongchon

2010-12-01

344

1315 nm dielectric mirror fabrication by reactive sputtering  

SciTech Connect

Progress in an on-going effort to fabricate improved laser mirrors from reactively sputtered amorphous oxides (Nb, Ta, Ti, Si), nitrides (Si), and semiconductor alloys (Si:H) is reported. Optimum coating materials have been selected for use at 1315 nm. Materials for shorter wavelengths are also suggested. Supporting data include laser calorimetric absorption coefficients, surface roughnesses deduced from total integrated scattering, refractive indices, and residual mechanical stress levels. An automated reactive gas exchange technique is described for mirror fabrication. Laser calorimetry, total integrated scattering and environmental stability results are presented for fabricated mirrors. Reflectances greater than 0.999 have been achieved.

Pawlewicz, W.T.; Martin, P.M.; Griffin, J.W.; Temple, P.A.

1984-10-01

345

FROM THE ISR TO RHIC - MEASUREMENTS OF HARD-SCATTERING AND JETS USING INCLUSIVE SINGLE PARTICLE PRODUCTION AND 2-PARTICLE CORRELATIONS.  

SciTech Connect

Hard scattering in p-p collisions, discovered at the CERN ISR in 1972 by the method of leading particles, proved that the partons of Deeply Inelastic Scattering strongly interacted with each other. Further ISR measurements utilizing inclusive single or pairs of hadrons established that high p{sub T} particles are produced from states with two roughly back-to-back jets which are the result of scattering of constituents of the nucleons as described by Quantum Chromodynamics (QCD), which was developed during the course of these measurements. These techniques, which are the only practical method to study hard-scattering and jet phenomena in Au+Au central collisions at RHIC energies, are reviewed, as an introduction to present RHIC measurements.

TANNENBAUM, M.J.

2005-04-23

346

From the ISR to RHIC--measurements of hard-scattering and jets using inclusive single particle production and 2-particle correlations  

E-print Network

Hard scattering in p-p collisions, discovered at the CERN ISR in 1972 by the method of leading particles, proved that the partons of Deeply Inelastic Scattering strongly interacted with each other. Further ISR measurements utilizing inclusive single or pairs of hadrons established that high pT particles are produced from states with two roughly back-to-back jets which are the result of scattering of constituents of the nucleons as desribed by Quantum Chromodynamics (QCD), which was developed during the course of these measurements. These techniques, which are the only practical method to study hard-scattering and jet phenomena in Au+Au central collisions at RHIC energies, are reviewed, as an introduction to present RHIC measurements.

M. J. Tannenbaum

2005-07-13

347

Globular adiponectin inhibits ethanol-induced reactive oxygen species production through modulation of NADPH oxidase in macrophages: involvement of liver kinase B1/AMP-activated protein kinase pathway.  

PubMed

Adiponectin, an adipokine predominantly secreted from adipocytes, has been shown to play protective roles against chronic alcohol consumption. Although excessive reactive oxygen species (ROS) production in macrophages is considered one of the critical events for ethanol-induced damage in various target tissues, the effect of adiponectin on ethanol-induced ROS production is not clearly understood. In the present study, we investigated the effect of globular adiponectin (gAcrp) on ethanol-induced ROS production and the potential mechanisms underlying these effects of gAcrp in macrophages. Here we demonstrated that gAcrp prevented ethanol-induced ROS production in both RAW 264.7 macrophages and primary murine peritoneal macrophages. Globular adiponectin also inhibited ethanol-induced activation of NADPH oxidase. In addition, gAcrp suppressed ethanol-induced increase in the expression of NADPH oxidase subunits, including Nox2 and p22(phox), via modulation of nuclear factor-?B pathway. Furthermore, pretreatment with compound C, a selective inhibitor of AMPK, or knockdown of AMPK by small interfering RNA restored suppression of ethanol-induced ROS production and Nox2 expression by gAcrp. Finally, we found that gAcrp treatment induced phosphorylation of liver kinase B1 (LKB1), an upstream signaling molecule mediating AMPK activation. Knockdown of LKB1 restored gAcrp-suppressed Nox2 expression, suggesting that LKB1/AMPK pathway plays a critical role in the suppression of ethanol-induced ROS production and activation of NADPH oxidase by gAcrp. Taken together, these results demonstrate that globular adiponectin prevents ethanol-induced ROS production, at least in part, via modulation of NADPH oxidase in macrophages. Further, LKB1/AMPK axis plays an important role in the suppression of ethanol-induced NADPH oxidase activation by gAcrp in macrophages. PMID:24850909

Kim, Mi Jin; Nagy, Laura E; Park, Pil-Hoon

2014-09-01

348

Phytate, reactive oxygen species and colorectal cancer.  

PubMed

Reproducible high-performance liquid chromatography methods have been developed and validated which allow an accurate quantification of phytic acid in faeces and food and reactive oxygen species in an in vitro model system and in faecal specimens. When applied to the evaluation of reactive oxygen species generation by faeces, this method has shown that 1:100 dilutions of matrix obtained from stool samples of adenoma patients are capable of generating significant quantities of reactive oxygen species as evinced by the production of diphenols from salicylic acid. Moreover, it has been shown that the major product of HO. attack on salicylic acid is 2,5-dihydroxy benzoic acid and not 2, 3-dihydroxy benzoic acid as previously reported. In the presence of the antioxidant ascorbic acid the inhibitory capacity of phytic acid on the generation of reactive oxygen species is completely subverted. Therefore, the kinetics of reactive oxygen species production by faeces is currently under further investigation by high-performance liquid chromatography and chemiluminescence in various patient groups and may give an insight into the role of reactive oxygen species in the aetiology of colorectal cancer. PMID:9696942

Owen, R W; Spiegelhalder, B; Bartsch, H

1998-05-01

349

Withaferin A-caused production of intracellular reactive oxygen species modulates apoptosis via PI3K/Akt and JNKinase in rabbit articular chondrocytes.  

PubMed

Withaferin A (WFA) is known as a constituent of Ayurvedic medicinal plant, Withania somnifera, and has been used for thousands of years. Although WFA has been used for the treatment of osteoarthritis (OA) and has a wide range of biochemical and pharmacologic activities, there are no findings suggesting its properties on chondrocytes or cartilage. The aim of the present study is to investigate the effects of WFA on apoptosis with focus on generation of intracellular reactive oxygen species (ROS). Here we showed that WFA significantly increased the generation of intracellular ROS in a dose-dependent manner. We also determined that WFA markedly leads to apoptosis as evidenced by accumulation of p53 by Western blot analysis. N-Acetyl-L-Cystein (NAC), an antioxidant, prevented WFA-caused expression of p53 and inhibited apoptosis of chondrocytes. We also found that WFA causes the activation of PI3K/Akt and JNKinase. Inhibition of PI3K/Akt and JNKinase with LY294002 (LY)/triciribine (TB) or SP600125 (SP) in WFA-treated cells reduced accumulation of p53 and inhibited fragmented DNA. Our findings suggested that apoptosis caused by WFA-induced intracellular ROS generation is regulated through PI3K/Akt and JNKinase in rabbit articular chondrocytes. PMID:25120312

Yu, Seon-Mi; Kim, Song-Ja

2014-08-01

350

Berberine inhibits the production of lysophosphatidylcholine-induced reactive oxygen species and the ERK1/2 pathway in vascular smooth muscle cells.  

PubMed

Lysophosphatidylcholine (lysoPC) induces vascular smooth muscle cell (VSMC) proliferation and migration, which has been proposed to initiate the intimal thickening in coronary atherosclerotic lesions. Berberine is an alkaloid in Berberis aquifolium and many other plants. Recently, it has been shown to have beneficial effects on the cardiovascular system, such as anti-hyperglycemic and cholesterol-lowering activity. In this study, we investigated its effects on lysoPC-induced VSMC proliferation and migration. Berberine inhibited lysoPC-induced DNA synthesis and cell proliferation in VSMCs, as well as migration of the lysoPC-stimulated VSMCs. It also inhibited the activation of extracellular signal-regulated kinases (ERKs) and reduced transcription factor AP-1 activity and the lysoPC-induced increases in intracellular reactive oxygen species (ROS). These results indicate that the inhibitory effects of berberine on lysoPC-stimulated VSMC proliferation and migration are attributable to inhibition of ROS generation and hence of activation of the ERK1/2 pathway. This suggests that berberine has potential in the prevention of atherosclerosis and restenosis. PMID:16404160

Cho, Bong-Jun; Im, Eun Kyoung; Kwon, Jun Hye; Lee, Kyung-Hye; Shin, Hye-Jin; Oh, Jaewon; Kang, Seok-Min; Chung, Ji Hyung; Jang, Yangsoo

2005-12-31

351

Withaferin A-Caused Production of Intracellular Reactive Oxygen Species Modulates Apoptosis via PI3K/Akt and JNKinase in Rabbit Articular Chondrocytes  

PubMed Central

Withaferin A (WFA) is known as a constituent of Ayurvedic medicinal plant, Withania somnifera, and has been used for thousands of years. Although WFA has been used for the treatment of osteoarthritis (OA) and has a wide range of biochemical and pharmacologic activities, there are no findings suggesting its properties on chondrocytes or cartilage. The aim of the present study is to investigate the effects of WFA on apoptosis with focus on generation of intracellular reactive oxygen species (ROS). Here we showed that WFA significantly increased the generation of intracellular ROS in a dose-dependent manner. We also determined that WFA markedly leads to apoptosis as evidenced by accumulation of p53 by Western blot analysis. N-Acetyl-L-Cystein (NAC), an antioxidant, prevented WFA-caused expression of p53 and inhibited apoptosis of chondrocytes. We also found that WFA causes the activation of PI3K/Akt and JNKinase. Inhibition of PI3K/Akt and JNKinase with LY294002 (LY)/triciribine (TB) or SP600125 (SP) in WFA-treated cells reduced accumulation of p53 and inhibited fragmented DNA. Our findings suggested that apoptosis caused by WFA-induced intracellular ROS generation is regulated through PI3K/Akt and JNKinase in rabbit articular chondrocytes. Graphical Abstract PMID:25120312

2014-01-01

352

Reactive aggression and suicide  

Microsoft Academic Search

Aggression confers risk for suicide. However, “aggression” is a heterogeneous construct, and it is likely that subgroups of individuals with particular types of aggression are at higher risk. We postulate that a subtype of aggression, reactive aggression, underlies the link with suicide with implications for suicide risk-recognition and prevention. The theoretical rationale and empirical evidence for the role of reactive

Kenneth R. Conner; Paul R. Duberstein; Yeates Conwell; Eric D. Caine

2003-01-01

353

Signaling Pathways Controlling The Production Of Inflammatory Mediators in Response To Crystalline Silica Exposure: Role Of Reactive Oxygen\\/Nitrogen Species  

Microsoft Academic Search

Occupational exposure to crystalline silica has been linked to pulmonary fibrosis and lung cancer. Surface properties of crystalline silica are critical to the production of oxidant species, chemokines, inflammatory cytokines, and proliferative factors involved in the initiation and progression of silica-induced damage, inflammation, alveolar type II cell hyperplasia, fibroblast activation, and disease. The transcription factors nuclear factor ?B (NF-?B) and

Vincent Castranova

2004-01-01

354

Reactive Nitrogen Species Reactivities with Nitrones: Theoretical and Experimental Studies  

PubMed Central

Reactive nitrogen species (RNS) such as nitrogen dioxide (•NO2), peroxynitrite (ONOO–), and nitrosoperoxycarbonate (ONOOCO2–) are among the most damaging species present in biological systems due to their ability to cause modification of key biomolecular systems through oxidation, nitrosylation and nitration. Nitrone spin traps are known to react with free radicals and non-radicals via electrophilic and nucleophilic addition reactions, and have been employed as reagents to detect radicals using electron paramagnetic resonance (EPR) spectroscopy, and as pharmacological agents against oxidative stress-mediated injury. This study examines the reactivity of cyclic nitrones such as 5,5-dimethylpyrroline N-oxide (DMPO) with, •NO2, ONOO–, ONOOCO2–, SNAP and SIN-1 using EPR. The thermochemistries of nitrone reactivity with RNS, and isotropic hfsc's of the addition products were also calculated at the PCM(water)/B3LYP/6-31+G**//B3LYP/6-31G* level of theory with and without explicit water molecules in order to rationalize the nature of the observed EPR spectra. Spin trapping of other RNS such as azide (•N3), nitrogen trioxide (•NO3), amino (•NH2) radicals, and nitroxyl (HNO) were also theoretically and experimentally investigated by EPR spin trapping and mass spectrometry. This study also shows other spin traps such as AMPO, EMPO and DEPMPO can react with radical and non-radical RNS, thus, making spin traps suitable probes as well as antioxidants against RNS mediated oxidative damage. PMID:22775566

Nash, Kevin M.; Rockenbauer, Antal; Villamena, Frederick A.

2012-01-01

355

Mild coal pretreatment to improve liquefaction reactivity  

SciTech Connect

This report describes work completed during the fourth quarter of a three year project to study the effects of mild chemical pretreatment on coal dissolution reactivity during low severity liquefaction or coal/oil coprocessing. The overall objective of this research is to elucidate changes in the chemical and physical structure of coal by pretreating with methanol or other simple organic solvent and a trace amount of hydrochloric acid and measure the influence of these changes on coal dissolution reactivity. This work is part of a larger effort to develop a new coal liquefaction or coal/oil coprocessing scheme consisting of three main process steps: (1) mile pretreatment of the feed coal to enhance dissolution reactivity and dry the coal, (2) low severity thermal dissolution of the pretreated coal to obtain a very reactive coal-derived residual material amenable to upgrading, and (3) catalytic upgrading of the residual products to distillate liquids.

Miller, R.L.

1991-01-01

356

Single spin asymmetries in charged kaon production from semi-inclusive deep inelastic scattering on a transversely polarized 3He target  

We report the first measurement of target single spin asymmetries of charged kaons produced in semi-inclusive deep inelastic scattering of electrons off a transversely polarized 3He target. Both the Collins and Sivers moments, which are related to the nucleon transversity and Sivers distributions, respectively, are extracted over the kinematic range of 0.1

Zhao, Y. X.; Wang, Y.; Allada, K.; Aniol, K.; Annand, J. R.; Averett, T.; Benmokhtar, F.; Bertozzi, W.; Bradshaw, P. C.; Bosted, P.; Camsonne, A.; Canan, M.; Cates, G. D.; Chen, C.; Chen, J.-P.; Chen, W.; Chirapatpimol, K.; Chudakov, E.; Cisbani, E.; Cornejo, J. C.; Cusanno, F.; Dalton, M. M.; Deconinck, W.; de Jager, C. W.; De Leo, R.; Deng, X.; Deur, A.; Ding, H.; Dolph, P. A.; Dutta, C.; Dutta, D.; El Fassi, L.; Frullani, S.; Gao, H.; Garibaldi, F.; Gaskell, D.; Gilad, S.; Gilman, R.; Glamazdin, O.; Golge, S.; Guo, L.; Hamilton, D.; Hansen, O.; Higinbotham, D. W.; Holmstrom, T.; Huang, J.; Huang, M.; Ibrahim, H. F.; Iodice, M.; Jiang, X.; Jin, G.; Jones, M. K.; Katich, J.; Kelleher, A.; Kim, W.; Kolarkar, A.; Korsch, W.; LeRose, J. J.; Li, X.; Li, Y.; Lindgren, R.; Liyanage, N.; Long, E.; Lu, H.-J.; Margaziotis, D. J.; Markowitz, P.; Marrone, S.; McNulty, D.; Meziani, Z.-E.; Michaels, R.; Moffit, B.; Munoz Camacho, C; Nanda, S.; Narayan, A.; Nelyubin, V.; Norum, B.; Oh, Y.; Osipenko, M.; Parno, D.; Peng, J.-C.; Phillips, S. K.; Posik, M.; Puckett, A. J.; Qian, X.; Qiang, Y.; Rakhman, A.; Ransome, R.; Riordan, S.; Saha, A.; Sawatzky, B.; Schulte, E.; Shahinyan, A.; Shabestari, M. H.; Sirca, S; Stepanyan, S.; Subedi, R.; Sulkosky, V.; Tang, L.-G.; Tobias, A.; Urciuoli, G. M.; Vilardi, I.; Wang, K.; Wojtsekhowski, B.; Yan, X.; Yao, H.; Ye, Y.; Ye, Z.; Yuan, L.; Zhan, X.; Zhang, Y.; Zhang, Y.-W.; Zhao, B.; Zheng, X.; Zhu, L.; Zhu, X.; Zong, X.

2014-11-01

357

Corners Always Scatter  

NASA Astrophysics Data System (ADS)

We study time harmonic scattering for the Helmholtz equation in . We show that certain penetrable scatterers with rectangular corners scatter every incident wave nontrivially. Even though these scatterers have interior transmission eigenvalues, the relative scattering (a.k.a. far field) operator has a trivial kernel and cokernel at every real wavenumber.

Blåsten, Eemeli; Päivärinta, Lassi; Sylvester, John

2014-10-01

358

Particle-reactive radionuclides (234Th, 210Pb, 210) as tracers for the estimation of export production in the South China Sea  

NASA Astrophysics Data System (ADS)

The time-series station, SEATS (18° N, 116° E) in the South China Sea was visited six times during October 2006-December 2008 to carry out seawater sampling and floating trap deployments for the determination of distributions and fluxes of POC, PIC, PN, 234Th, 210Pb, and 210Po in the upper 200 m of the water column. Radionuclide deficiencies resulted in removal fluxes from the euphotic layer of 1.1×103-1.8×103 dpm m-2d-1 and 7.1-40.2 dpm m-2d-1 for 234Th and 210Po, respectively. Due to atmospheric input, an excess of 210Pb relative to 226Ra is commonly observed in the upper water column. Sinking fluxes of total mass, POC, PIC, PN, 234Th, 210Pb, and 210Po measured at the euphotic depth were low in summer-fall and high in winter-spring, reflecting the seasonal variability of biological pumping. Excluding the suspiciously low primary productivity data point in July 2007, a relatively high e-ratio of 0.28-0.69 was estimated by the ratio of the POC flux at the euphotic depth and the integrated primary productivity. The ratios of 234Th, 210Pb, and 210Po to organic carbon, inorganic carbon, and nitrogen in the sinking particles were combined with the disequilibria of 234Th-238U, 210Pb-226Ra, and 210Po-210Pb to estimate export fluxes of POC, PIC, and PN from the euphotic layer. Compared with measured fluxes by the sediment trap and estimated fluxes by other approaches, it is concluded that the export production in the South China Sea, ranging from 1.8 to 21.3 mmol-C m-2d-1, can be reasonably estimated using 234Th, 210Pb, and 210Po as carbon proxies.

Wei, C.-L.; Lin, S.-Y.; Sheu, D. D.-D.; Chou, W.-C.; Yi, M.-C.; Santschi, P. H.; Wen, L.-S.

2011-12-01

359

Particle-reactive radionuclides (234Th, 210Pb, 210Po) as tracers for the estimation of export production in the South China Sea  

NASA Astrophysics Data System (ADS)

The time-series station, SEATS (18° N, 116° E) in the South China Sea was visited six times during October 2006-December 2008 to carry out seawater sampling and floating trap deployments for the determination of distributions and fluxes of POC, PIC, PN, 234Th, 210Pb, and 210Po in the upper 200 m of the water column. Radionuclide deficiencies resulted in removal fluxes from the euphotic layer of 1.1 × 103-1.8 × 103 dpm m-2 d-1 and 7.1-40.2 dpm m-2 d-1 for 234Th and 210Po, respectively. Due to atmospheric input, an excess of 210Pb relative to 226Ra is commonly observed in the upper water column. Sinking fluxes of total mass, POC, PIC, PN, 234Th, 210Pb, and 210Po measured at the euphotic depth were low in summer-fall and high in winter-spring, reflecting the seasonal variability of biological pumping. Excluding the suspiciously low primary productivity data point in July 2007, a relatively high e-ratio of 0.28-0.69 was estimated by the ratio of the POC flux at the euphotic depth and the integrated primary productivity. The ratios of 234Th, 210Pb, and 210Po to organic carbon, inorganic carbon, and nitrogen in the sinking particles were combined with the disequilibria of 234Th-238U, 210Pb-226Ra, and 210Po-210Pb to estimate export fluxes of POC, PIC, and PN from the euphotic layer. Compared with measured fluxes by the sediment trap and estimated fluxes by other approaches, it is concluded that the export production in the South China Sea, ranging from 1.8 to 21.3 mmol-C m-2 d-1, can be reasonably estimated using 234Th, 210Pb, and 210Po as carbon proxies.

Wei, C.-L.; Lin, S.-Y.; Sheu, D. D.-D.; Chou, W.-C.; Yi, M.-C.; Santschi, P. H.; Wen, L.-S.

2011-09-01

360

Radiochemistry: Flipping fluoride's reactivity  

NASA Astrophysics Data System (ADS)

A sophisticated palladium(IV)-based species allows nucleophilic fluoride to react as an electrophilic fluorination reagent. This long-awaited reactivity will be especially useful in the preparation of radiochemically labelled molecules for positron emission tomography studies.

Gouverneur, Véronique

2012-03-01

361

Non-reactive scattering of excited exotic hydrogen atoms  

E-print Network

The Coulomb deexcitation of light exotic atoms in collisions with hydrogen atoms has been studied in the framework of the fully quantum-mechanical close-coupling method for the first time. The calculations of the $l$-averaged cross sections have been performed for $(\\mu p)_n$ and $(\\mu d)_n$ atoms in the states with the principal quantum number $n=3 \\div 8$ and relative energies region $E=0.01 \\div 100$ eV. The obtained results reveal the new $n$ and $E$ dependences of the Coulomb deexcitation cross sections. The large fraction (up to $\\sim$ 36%) of the transition with $\\Delta n > 1$ is also predicted.

G. Ya. Korenman; V. P. Popov; V. N. Pomerantsev

2005-01-13

362

DIFFUSE SCATTERING Hercules 2008  

E-print Network

- Barium IV: self-hosting incommensurate structure - Nanotubes@zeolite: structural characteristics-kind disorder Average structure ORDER Bragg peaks 2-body correlations DISORDER Diffuse scattering Average long Same scattering patterns! Scattering experiments: probe 2-body correlations Ambiguities can exist

Paris-Sud 11, Université de

363

Reactive Power Compensator.  

DOEpatents

A system and method for determining and providing reactive power compensation for an inductive load. A reactive power compensator (50,50') monitors the voltage and current flowing through each of three distribution lines (52a, 52b, 52c), which are supplying three-phase power to one or more inductive loads. Using signals indicative of the current on each of these lines when the voltage waveform on the line crosses zero, the reactive power compensator determines a reactive power compensator capacitance that must be connected to the lines to maintain a desired VAR level, power factor, or line voltage. Alternatively, an operator can manually select a specific capacitance for connection to each line, or the capacitance can be selected based on a time schedule. The reactive power compensator produces control signals, which are coupled through optical fibers (102/106) to a switch driver (110, 110') to select specific compensation capacitors (112) for connections to each line. The switch driver develops triggering signals that are supplied to a plurality of series-connected solid state switches (350), which control charge current in one direction in respect to ground for each compensation capacitor. During each cycle, current flows from ground to charge the capacitors as the voltage on the line begins to go negative from its positive peak value. The triggering signals are applied to gate the solid state switches into a conducting state when the potential on the lines and on the capacitors reaches a negative peak value, thereby minimizing both the potential difference and across the charge current through the switches when they begin to conduct. Any harmonic distortion on the potential and current carried by the lines is filtered out from the current and potential signals used by the reactive power compensator so that it does not affect the determination of the required reactive compensation. 26 figs.

El-Sharkawi, M.A.; Venkata, S.S.; Chen, M.; Andexler, G.; Huang, T.

1992-07-28

364

Reactive power compensator  

DOEpatents

A system and method for determining and providing reactive power compensation for an inductive load. A reactive power compensator (50,50') monitors the voltage and current flowing through each of three distribution lines (52a, 52b, 52c), which are supplying three-phase power to one or more inductive loads. Using signals indicative of the current on each of these lines when the voltage waveform on the line crosses zero, the reactive power compensator determines a reactive power compensator capacitance that must be connected to the lines to maintain a desired VAR level, power factor, or line voltage. Alternatively, an operator can manually select a specific capacitance for connection to each line, or the capacitance can be selected based on a time schedule. The reactive power compensator produces control signals, which are coupled through optical fibers (102/106) to a switch driver (110, 110') to select specific compensation capacitors (112) for connections to each line. The switch driver develops triggering signals that are supplied to a plurality of series-connected solid state switches (350), which control charge current in one direction in respect to ground for each compensation capacitor. During each cycle, current flows from ground to charge the capacitors as the voltage on the line begins to go negative from its positive peak value. The triggering signals are applied to gate the solid state switches into a conducting state when the potential on the lines and on the capacitors reaches a negative peak value, thereby minimizing both the potential difference and across the charge current through the switches when they begin to conduct. Any harmonic distortion on the potential and current carried by the lines is filtered out from the current and potential signals used by the reactive power compensator so that it does not affect the determination of the required reactive compensation.

El-Sharkawi, Mohamed A. (Renton, WA); Venkata, Subrahmanyam S. (Woodinville, WA); Chen, Mingliang (Kirkland, WA); Andexler, George (Everett, WA); Huang, Tony (Seattle, WA)

1992-01-01

365

Increased production of mitochondrial reactive oxygen species and reduced adult life span in an insecticide-resistant strain of Anopheles gambiae.  

PubMed

Control of the malaria vector An. gambiae is still largely obtained through chemical intervention using pyrethroids, such as permethrin. However, strains of An. gambiae that are resistant to the toxic effects of pyrethroids have become widespread in several endemic areas over the last decade. The objective of this study was to assess differences in five life-history traits (larval developmental time and the body weight, fecundity, hatch rate, and longevity of adult females) and energy metabolism between a strain of An. gambiae that is resistant to permethrin (RSP), due to knockdown resistance and enhanced metabolic detoxification, and a permethrin susceptible strain reared under laboratory conditions. We also quantified the expression levels of five antioxidant enzyme genes: GSTe3, CAT, GPXH1, SOD1, and SOD2. We found that the RSP strain had a longer developmental time than the susceptible strain. Additionally, RSP adult females had higher wet body weight and increased water and glycogen levels. Compared to permethrin susceptible females, RSP females displayed reduced metabolic rate and mitochondrial coupling efficiency and higher mitochondrial ROS production. Furthermore, despite higher levels of GSTe3 and CAT transcripts, RSP females had a shorter adult life span than susceptible females. Collectively, these results suggest that permethrin resistance alleles might affect energy metabolism, oxidative stress, and adult survival of An. gambiae. However, because the strains used in this study differ in their genetic backgrounds, the results need to be interpreted with caution and replicated in other strains to have significant implications for malaria transmission and vector control. PMID:24555527

Otali, D; Novak, R J; Wan, W; Bu, S; Moellering, D R; De Luca, M

2014-06-01

366

Overexpression of Pyruvate Dehydrogenase Kinase 1 and Lactate Dehydrogenase A in Nerve Cells Confers Resistance to Amyloid ? and Other Toxins by Decreasing Mitochondrial Respiration and Reactive Oxygen Species Production*  

PubMed Central

We previously demonstrated that nerve cell lines selected for resistance to amyloid ? (A?) peptide exhibit elevated aerobic glycolysis in part due to increased expression of pyruvate dehydrogenase kinase 1 (PDK1) and lactate dehydrogenase A (LDHA). Here, we show that overexpression of either PDK1 or LDHA in a rat CNS cell line (B12) confers resistance to A? and other neurotoxins. Treatment of A?-sensitive cells with various toxins resulted in mitochondrial hyperpolarization, immediately followed by rapid depolarization and cell death, events accompanied by increased production of cellular reactive oxygen species (ROS). In contrast, cells expressing either PDK1 or LDHA maintained a lower mitochondrial membrane potential and decreased ROS production with or without exposure to toxins. Additionally, PDK1- and LDHA-overexpressing cells exhibited decreased oxygen consumption but maintained levels of ATP under both normal culture conditions and following A? treatment. Interestingly, immunoblot analysis of wild type mouse primary cortical neurons treated with A? or cortical tissue extracts from 12-month-old APPswe/PS1dE9 transgenic mice showed decreased expression of LDHA and PDK1 when compared with controls. Additionally, post-mortem brain extracts from patients with Alzheimer disease exhibited a decrease in PDK1 expression compared with nondemented patients. Collectively, these findings indicate that key Warburg effect enzymes play a central role in mediating neuronal resistance to ?? or other neurotoxins by decreasing mitochondrial activity and subsequent ROS production. Maintenance of PDK1 or LDHA expression in certain regions of the brain may explain why some individuals tolerate high levels of A? deposition without developing Alzheimer disease. PMID:22948140

Newington, Jordan T.; Rappon, Tim; Albers, Shawn; Wong, Daisy Y.; Rylett, R. Jane; Cumming, Robert C.

2012-01-01

367

Increasing cytotoxic activity and production of reactive oxygen and nitrogen intermediates by peritoneal macrophages during the development of multiple organ dysfunction syndrome in mice.  

PubMed

A major problem in the intensive care unit nowadays is the development of multiple organ dysfunction syndrome (MODS), a cumulative sequence of progressive deterioration of organ functions. While the pathogenic pathways of MODS remain to be elucidated, it is assumed that cells of the host defence system, especially the macrophages, are altered in their function. During the development of MODS it is assumed that macrophages are overactivated and that an exaggerated inflammatory response may contribute to its pathogenesis. In order to gain insight into the alterations of the functional status of the macrophage during the development of MODS, a series of macrophage functions was measured in the subsequent phases of zymosan induced generalized inflammation in mice. Male C57BL/6 mice received a single dose of zymosan intraperitoneally and groups of animals were killed after 2, 5, 8, and 12 days. Peritoneal macrophages were collected for in vitro assessment of the ADCC, the production of superoxide (O2-) and nitric oxide (NO), and complement mediated phagocytosis and intracellular killing of Staphylococcus aureus. A single intraperitoneal injection with zymosan resulted in a three-phase illness. During the third phase the animals developed MODS-like symptoms. Peritoneal cells from control animals produced very low to non-detectable amounts of O2- and NO, and the cytotoxic activity was also low. During the development of MODS, from day 7 onwards, the ability to produce O2- and NO2- became strongly elevated, as did the cytotoxic activity. These findings are in parallel with the development of MODS whereas the phagocytic and killing capacity remained essentially unaltered. The changes found could be detrimental for the organism, thus possibly contributing to the onset and development of MODS. PMID:8845029

Jansen, M J; Hendriks, T; Huyben, C M; Tax, W J; van der Meer, J W; Goris, R J

1996-10-01

368

Reactive Depression in Youths Experiencing Emancipation.  

ERIC Educational Resources Information Center

Briefly evaluates the Independent Living Subsidy Program (ILSP) designed to enable adolescents to make an effective transition from foster care, institutional living, or other forms of substitute care to full and productive self-sufficiency. Focuses specifically on the four stages of reactive depression (anxiety, fear and loneliness, elation, and…

Anderson, James L.; Simonitch, Brian

1981-01-01

369

Curcumin stimulates reactive oxygen species production and potentiates apoptosis induction by the antitumor drugs arsenic trioxide and lonidamine in human myeloid leukemia cell lines.  

PubMed

Arsenic trioxide (ATO, Trisenox) is an important antileukemic drug, but its efficacy is frequently low when used as a single agent. Here, we demonstrate that the apoptotic action of ATO is greatly increased when combined with subcytotoxic curcumin concentrations in U937 and HL60 human acute myeloid leukemia cells, and with lower efficacy in K562 chronic myelogenous leukemia cells. Curcumin exerts similar cooperative effect with the mitochondria-targeting drug lonidamine, whereas the response is negligible in combination with the DNA-targeting drug cisplatin. Curcumin plus ATO or lonidamine stimulates typical events of the mitochondrial executioner pathway (Bax and Bid activation, cytochrome c release, X-linked inhibitor of apoptosis down-regulation, and caspase-9/-3 activation) and causes mitochondrial transmembrane potential dissipation, which nevertheless represents a late event in the apoptotic response. Curcumin increases anion superoxide production, and its proapoptotic action in combination with ATO and lonidamine is mimicked by pro-oxidant agents (2-methoxyestradiol and H(2)O(2)) and prevented by antioxidant agents [Mn(III)tetrakis(4-benzoic acid)porphyrin chloride and N-acetyl-l-cysteine]. Within the assayed time period (16-24 h), curcumin does not significantly modify p38-mitogen-activated protein kinase and c-Jun NH(2)-terminal kinase phosphorylation/activation or nuclear factor-?B activity, but it greatly stimulates extracellular signal-regulated kinase (ERK) phosphorylation, and decreases Akt phosphorylation. Experiments using mitogen-activated protein kinase kinase/ERK inhibitors [2'-amino-3'-methoxyflavone (PD98059) and 1,4-diamino-2,3-dicyano-1,4-bis(2-aminophenylthio)butadiene (U0126)] and phosphatidylinositol 3-kinase inhibitor 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (LY294002) indicate that ERK activation does not mediate and even restrains apoptosis potentiation, whereas Akt down-regulation facilitates apoptosis generation. In summary, cotreatment with curcumin may represent a useful manner of increasing the efficacy of ATO and lonidamine as antitumor drugs in myeloid leukemia cells. PMID:20605902

Sánchez, Yolanda; Simón, Gloria P; Calviño, Eva; de Blas, Elena; Aller, Patricio

2010-10-01

370

Personality processes in anger and reactive aggression: an introduction.  

PubMed

The situational factors precipitating anger and reactive (i.e., emotional) aggression have been well documented in the social psychology literature. However, there are pronounced individual differences in reactivity to hostile cues that are equally important in understanding such outcomes. Indeed, in predicting tendencies toward anger and reactive aggression, it appears critical to simultaneously consider both individual difference and situational factors. This case is first made. Subsequently, the utility of this individual difference realm in understanding wider personality processes related to social cognition, reactivity, and self-regulation is highlighted. Individual difference frameworks of this type are scattered across multiple literatures. For this reason, the present special section of the Journal of Personality invited contributions from experts in developmental, social, cognitive, trait, and biological subdisciplines of psychology. The final section introduces the invited papers and makes a brief case for broader process-related conclusions that are generally apparent. PMID:20433610

Robinson, Michael D; Wilkowski, Benjamin M

2010-02-01

371

Interactive chemical reactivity exploration.  

PubMed

Elucidating chemical reactivity in complex molecular assemblies of a few hundred atoms is, despite the remarkable progress in quantum chemistry, still a major challenge. Black-box search methods to find intermediates and transition-state structures might fail in such situations because of the high-dimensionality of the potential energy surface. Here, we propose the concept of interactive chemical reactivity exploration to effectively introduce the chemist's intuition into the search process. We employ a haptic pointer device with force feedback to allow the operator the direct manipulation of structures in three dimensions along with simultaneous perception of the quantum mechanical response upon structure modification as forces. We elaborate on the details of how such an interactive exploration should proceed and which technical difficulties need to be overcome. All reactivity-exploration concepts developed for this purpose have been implemented in the samson programming environment. PMID:25205397

Haag, Moritz P; Vaucher, Alain C; Bosson, Maël; Redon, Stéphane; Reiher, Markus

2014-10-20

372

The Penrose photoproduction scenario for NGC 4151: A black hole gamma-ray emission mechanism for active galactic nuclei and Seyfert galaxies. [Compton scattering and pair production  

NASA Technical Reports Server (NTRS)

A consistent theoretical interpretation is given for the suggestion that a steepening of the spectrum between X-ray and gamma ray energies may be a general, gamma-ray characteristic of Seyfert galaxies, if the diffuse gamma ray spectrum is considered to be a superposition of unresolved contributions, from one or more classes of extragalactic objects. In the case of NGC 4151, the dominant process is shown to be Penrose Compton scattering in the ergosphere of a Kerr black hole, assumed to exist in the Seyfert's active galactic nucleus.

Leiter, D.

1979-01-01

373

Quantum Multiple Scattering: Correspondence between  

E-print Network

Quantum Multiple Scattering: Correspondence between Particle and Photon Scattering A thesis Multiple Scattering: Correspondence between Particle and Photon Scattering Sheng Li, June 2003 Thesis advisor: Prof. Eric J. Heller This thesis discusses the quantum multiple scattering theory of both par

Heller, Eric

374

Reactive Arthritis Diagnosis  

MedlinePLUS

... A doctor will take the patient's complete medical history, noting current symptoms as well as any previous diseases, problems and infections. In addition to evaluating symptoms, diagnostic signs of reactive ... worse. A history of swelling in the feet and hands, especially ...

375

Reactive power compensating system  

DOEpatents

The reactive power of an induction machine is compensated by providing fixed capacitors on each phase line for the minimum compensation required, sensing the current on one line at the time its voltage crosses zero to determine the actual compensation required for each phase, and selecting switched capacitors on each line to provide the balance of the compensation required.

Williams, Timothy J. (Redondo Beach, CA); El-Sharkawi, Mohamed A. (Renton, WA); Venkata, Subrahmanyam S. (Seattle, WA)

1987-01-01

376

Terahertz Scattering  

NASA Astrophysics Data System (ADS)

Terahertz (THz) Time Domain Spectroscopy (TDS) measurements have the unique ability to detect both the amplitude and phase of the electric field, simultaneously. This eliminates complications introduced by Kramers-Kronig relations typically used in near-infrared spectroscopy. Many materials of interest contain resonant features in their refractive indices in the far-infrared (THz) spectrum, while their packaging materials are generally transparent. Thus, an important application for THz TDS is the ability to see inside packa