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Sample records for reactively scattered products

  1. Quantum superposition of target and product states in reactive electron scattering from CF4 revealed through velocity slice imaging.

    PubMed

    marsson, Frmann H; Szymanska, Ewelina; Mason, Nigel J; Krishnakumar, E; Inglfsson, Oddur

    2013-08-01

    Exploiting the technique of velocity slice imaging, we have performed a detailed study of reactive electron scattering with CF4. We have measured the electron impact energy dependence of both the angular and kinetic energy distributions of the channels yielding F- and CF3(-) anions. These data provide an unprecedented insight into the quantum superposition of the target state and product channels, respectively, of Td and C3v symmetry, and shed new light on the dissociation dynamics. PMID:23971572

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

    NASA Astrophysics Data System (ADS)

    Cvita, Marko T.; Althorpe, Stuart C.

    2013-08-01

    We extend a recently developed wave packet method for computing the state-to-state quantum dynamics of AB + CD ? ABC + D reactions [M. T. Cvita 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.

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

    PubMed Central

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

    2011-01-01

    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

  4. State-to-state dynamics of high-n Rydberg H-atom scattering with H2: inelastic scattering and reactive scattering.

    PubMed

    Yu, Shengrui; Su, Shu; Dai, Dongxu; Yuan, Kaijun; Yang, Xueming

    2015-04-21

    The state-to-state dynamics of high-n Rydberg H-atom scattering with para-H2 at the collision energies of 0.45 and 1.07 eV have been studied using the H-atom Rydberg tagging time-of-flight technique. Both the inelastic scattering and reactive scattering are observed in the experimental time-of-flight spectra. The products H2(v', j' = odd) come only from reactive scattering and present clearly forward-backward asymmetric angular distributions, which differ from those of the corresponding ion-molecule reaction. The products H2(v', j' = even), however, come from both reactive scattering and inelastic scattering. Simulating the rotational distribution from reactive scattering, we found that most of the H2(v', j' = even) products come from inelastic scattering. The angular distributions of the product H2(v', j' = even) are consistent with what is predicted by the conventional textbook mechanism of inelastic scattering, and are a little different from those of the corresponding ion-molecule inelastic scattering. These results suggest that the effect of Rydberg electron could not be neglected in describing the differential cross sections of H* + para-H2 scattering. From the simulation, the branching ratios of the inelastic scattering channel were determined to be 66% and 79% at the collision energies of 0.45 and 1.07 eV, respectively. PMID:25162182

  5. Protein-reactive natural products.

    PubMed

    Drahl, Carmen; Cravatt, Benjamin F; Sorensen, Erik J

    2005-09-12

    Researchers in the post-genome era are confronted with the daunting task of assigning structure and function to tens of thousands of encoded proteins. To realize this goal, new technologies are emerging for the analysis of protein function on a global scale, such as activity-based protein profiling (ABPP), which aims to develop active site-directed chemical probes for enzyme analysis in whole proteomes. For the pursuit of such chemical proteomic technologies, it is helpful to derive inspiration from protein-reactive natural products. Natural products use a remarkably diverse set of mechanisms to covalently modify enzymes from distinct mechanistic classes, thus providing a wellspring of chemical concepts that can be exploited for the design of active-site-directed proteomic probes. Herein, we highlight several examples of protein-reactive natural products and illustrate how their mechanisms of action have influenced and continue to shape the progression of chemical proteomic technologies like ABPP. PMID:16149114

  6. State-to-state inelastic and reactive molecular beam scattering from surfaces

    SciTech Connect

    Lykke, K.R. ); Kay, B.D. )

    1990-01-01

    Resonantly enhanced multiphoton ionization (REMPI) laser spectroscopic and molecular beam-surface scattering techniques are coupled to study inelastic and reactive gas-surface scattering with state-to-state specificity. Rotational, vibrational, translational and angular distributions have been measured for the inelastic scattering of HCI and N {sub 2} from Au(111). In both cases the scattering is direct-inelastic in nature and exhibits interesting dynamical features such as rotational rainbow scattering. In an effort to elucidate the dynamics of chemical reactions occurring on surfaces we have extended our quantum-resolved scattering studies to include the reactive scattering of a beam of gas phase H-atoms from a chlorinated metal surface M-CI. The nascent rotational and vibrational distributions of the HCI product are determined using REMPI. The thermochemistry for this reaction on Au indicates that the product formation proceeding through chemisorbed H-atoms is slightly endothermic while direct reaction of a has phase H-atom with M-CI is highly exothermic (ca. 50 kcal/mole). Details of the experimental techniques, results and implications regarding the scattering dynamics are discussed. 55 ref., 8 fig.

  7. Inelastic and reactive scattering of hyperthermal atomic oxygen from amorphous carbon

    NASA Technical Reports Server (NTRS)

    Minton, Timothy K.; Nelson, Christine M.; Brinza, David E.; Liang, Ranty H.

    1991-01-01

    The reaction of hyperthermal oxygen atoms with an amorphous carbon-13 surface was studied using a modified universal crossed molecular beams apparatus. Time-of-flight distributions of inelastically scattered O-atoms and reactively scattered CO-13 and CO2-13 were measured with a rotatable mass spectrometer detector. Two inelastic scattering channels were observed, corresponding to a direct inelastic process in which the scattered O-atoms retain 20 to 30 percent of their initial kinetic energy and to a trapping desorption process whereby O-atoms emerge from the surface at thermal velocities. Reactive scattering data imply the formation of two kinds of CO products, slow products whose translational energies are determined by the surface temperature and hyperthermal (Approx. 3 eV) products with translational energies comprising roughly 30 percent of the total available energy (E sub avl), where E sub avl is the sum of the collision energy and the reaction exothermicity. Angular data show that the hyperthermal CO is scattered preferentially in the specular direction. CO2 product was also observed, but at much lower intensities than CO and with only thermal velocities.

  8. Crossed-molecular-beams reactive scattering of oxygen atoms

    SciTech Connect

    Baseman, R.J.

    1982-11-01

    The reactions of O(/sup 3/P) with six prototypical unsaturated hydrocarbons, and the reaction of O(/sup 1/D) with HD, have been studied in high-resolution crossed-molecular-beams scattering experiments with mass-spectrometric detection. The observed laboratory-product angular and velocity distributions unambiguously identify parent-daughter ion pairs, distinguish different neutral sources of the same ion, and have been used to identify the primary products of the reactions. The derived center-of-mass product angular and translational energy distributions have been used to elucidate the detailed reaction dynamics. These results demonstrate that O(/sup 3/P)-unsaturated hydrocarbon chemistry is dominated by single bond cleavages, leading to radical products exclusively.

  9. Modern integral equation techniques for quantum reactive scattering theory

    SciTech Connect

    Auerbach, S.M.

    1993-11-01

    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.

  10. Quantum Theory of (H,H{Sub 2}) Scattering: Approximate Treatments of Reactive Scattering

    DOE R&D Accomplishments Database

    Tang, K. T.; Karplus, M.

    1970-10-01

    A quantum mechanical study is made of reactive scattering in the (H, H{sub 2}) system. The problem is formulated in terms of a form of the distorted-wave Born approximation (DWBA) suitable for collisions in which all particles have finite mass. For certain incident energies, differential and total cross sections, as well as other attributes of the reactive collisions, (e.g. reaction configuration), are determined. Two limiting models in the DWBA formulation are compared; in one, the molecule is unperturbed by the incoming atom and in the other, the molecule adiabatically follows the incoming atom. For thermal incident energies and semi-empirical interaction potential employed, the adiabatic model seems to be more appropriate. Since the DWBA method is too complicated for a general study of the (H, H{sub 2}) reaction, a much simpler approximation method, the “linear model” is developed. This model is very different in concept from treatments in which the three atoms are constrained to move on a line throughout the collision. The present model includes the full three-dimensional aspect of the collision and it is only the evaluation of the transition matrix element itself that is simplified. It is found that the linear model, when appropriately normalized, gives results in good agreement with that of the DWBA method. By application of this model, the energy dependence, rotational state of dependence and other properties of the total and differential reactions cross sections are determined. These results of the quantum mechanical treatment are compared with the classical calculation for the same potential surface. The most important result is that, in agreement with the classical treatment, the differential cross sections are strongly backward peaked at low energies and shifts in the forward direction as the energy increases. Finally, the implications of the present calculations for a theory of chemical kinetics are discussed.

  11. Quantum mechanics of chemical reactions: Recent developments in reactive scattering and in reaction path Hamiltonians

    SciTech Connect

    Miller, W.H.

    1988-12-01

    Two recent developments in the theory of chemical reaction dynamics are reviewed. First, it has recently been discovered that the S- matrix version of the Kohn variational principle is free of the ''Kohn anomalies'' that have plagued other versions and prevented its general use. This has considerably simplified quantum mechanical reactive scattering calculations, which provide the rigorous characterizations of bimolecular reactions. Second, a new kind of reaction path Hamiltonian has been developed, one based on the ''least motion'' path that interpolates linearly between the reactant and product geometry of the molecule (rather than the previously used minimum energy, or ''intrinsic'' reaction path). The form of Hamiltonian which results is much simpler than the original reaction path Hamiltonian, but more important is the fact that it provides a more physically correct description of hydrogen atom transfer reactions. 44 refs., 4 figs.

  12. Optimized preconditioners for Green function evaluation in quantum reactive scattering calculations

    NASA Astrophysics Data System (ADS)

    Poirier, Bill; Miller, William H.

    1997-01-01

    The optimal separable basis methodology is suggested for the efficient quantum-mechanical calculation of reactive and inelastic scattering amplitudes. The method gives rise to an optimally convergent distorted wave Born expansion of the Green's function. Computationally, this corresponds to an optimized DVR matrix preconditioning scheme. State-to-state and cumulative reactive scattering results are presented for the benchmark collinear H + H 2 → H 2 + H system. CPU time and memory requirements are drastically reduced in comparison with other methods, and results are obtained for previously prohibitive energy regimes.

  13. Light scattering measurement of sodium polyacrylate products

    NASA Astrophysics Data System (ADS)

    Lama, Nisha; Norwood, David; Boone, Steven; Massie-Boyer, Valerie

    2015-03-01

    In the presentation, we will describe the use of a multi-detector HPLC incorporating the DAWN EOS multi-angle laser light scattering (MALLS) detector to measure the properties such as molecular weight, RMS radius, contour and persistence length and polydispersity of sodium polyacrylate products. The samples of sodium polyacrylate are used in various industries as thickening agents, coating dispersants, artificial snow, laundry detergent and disposable diapers. Data and results obtained from the experiment will be presented.

  14. Mitochondrial reactive oxygen species production and elimination.

    PubMed

    Nickel, Alexander; Kohlhaas, Michael; Maack, Christoph

    2014-08-01

    Reactive oxygen species (ROS) play an important role in cardiovascular diseases, and one important source for ROS are mitochondria. Emission of ROS from mitochondria is the net result of ROS production at the electron transport chain (ETC) and their elimination by antioxidative enzymes. Both of these processes are highly dependent on the mitochondrial redox state, which is dynamically altered under different physiological and pathological conditions. The concept of "redox-optimized ROS balance" integrates these aspects and implies that oxidative stress occurs when the optimal equilibrium of an intermediate redox state is disturbed towards either strong oxidation or reduction. Furthermore, mitochondria integrate ROS signals from other cellular sources, presumably through a process termed "ROS-induced ROS release" that involves mitochondrial ion channels. Here, we attempt to integrate these recent advances in our understanding of the control of mitochondrial ROS emission and develop a concept of how in heart failure, defects in ion handling can lead to mitochondrial oxidative stress. This article is part of a Special Issue entitled "Redox Signalling in the Cardiovascular System". PMID:24657720

  15. Attractive reactivity of a natural product, zerumbone.

    PubMed

    Kitayama, Takashi

    2011-01-01

    Zerumbone is a cyclic seaquiterpene and, a potential resource for natural materials-related diversity-oriented synthesis (NMRDOS). Zerumbone, the main component of the essential oil of a wild ginger, Zingiber zerumbet Smith, showed strong reactivity with good chemo-, regio-, and stereoselectivity. To build the foundations for the industrial use of zerumbone, we examined conjugate addition, transannular reactions, ring cleavage, ring expansion, and asymmetric induction. The biological activity of zerumbone derivatives was also studied. PMID:21307568

  16. 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 ...

  17. The application of time-dependent wavepacket methods to reactive scattering

    NASA Technical Reports Server (NTRS)

    Neuhauser, Daniel; Baer, Michael; Judson, Richard S.; Kouri, Donald J.

    1991-01-01

    Several methods for performing numerically exact reactive scattering calculations using time-dependent wavepackets are reviewed. The basic idea is to take the multiarrangement reactive problem and reformulate it as one or more inelastic ones. In the simplest method, total reaction probabilities are extracted by calculating the flux of the wavepacket as it leaves the interaction region in the direction of the reactive arrangement. To make this practical, complex potentials that absorb the wavepacket before it reaches the numerical grid boundary are used. Methods that generate observables ranging from total, energy-averaged reaction probabilities up to energy- and state-resolved S-matrix elements are used. Techniques for efficiently performing the necessary inelastic wavepacket propagation are also reviewed.

  18. Light scatter from high reflectors deposited by reactive DC magnetron sputtering

    SciTech Connect

    Reicher, D.W.; Sobczak, J.; Black, J.P.; Petty, R.D.; Arguello, L.

    1997-12-01

    Scatter from optical thin film coatings is a significant problem for high power laser optics. Theoretical aspects of the problem have been well explored for scattering due to surface roughness. Over the past twenty years the surface roughness of optics has been significantly reduced. Improvements in optical surface fabrication and film deposition techniques have progressed to the point that even for complex coatings, surfaces of less than 1 nm rms roughness are routinely achievable. As the surface roughness of optics decreases, bulk scatter, rather than topographic scatter, may be the major scatter source in these smooth surfaces. Atomic force microscopy can profile the surface of a coating with atomic resolution. By comparing the power spectral density (PSD) derived from the surface profile with the PSD derived from angle resolved scatter measurements, some conclusions can be reached on this question. Data from analysis of dual wavelength high reflectors deposited by reactive DC magnetron sputtered Nb{sub 2}O{sub 3}SiO{sub 2} and ZrO{sub 2}SiO{sub 2} structures will be presented, allowing analysis of results for these film materials.

  19. State-to-state dynamics of the H(*)(n) + HD ? D(*)(n') + H2 reactive scattering.

    PubMed

    Yu, Shengrui; Su, Shu; Dai, Dongxu; Yuan, Kaijun; Yang, Xueming

    2014-01-21

    The state-to-state dynamics of the H(*)(n) + HD ? D(*)(n(')) + H2 reactive scattering at the collision energy of 0.5 eV have been carried out for the first time by using H-atom Rydberg tagging time-of-flight technique. Experimental results show that the angular distribution of the total H2 products presents clearly forward-backward asymmetric, which considerably differs from that of the corresponding H(+) + HD ? D(+) + H2 reaction predicted by previously theoretical calculations. Such disagreement between these two processes suggests that the Fermi independent-collider model is also not valid in describing the dynamics of isotopic variants of the H(*) + H2 reaction. The rotational state distribution of the H2 products demonstrates a saw-toothed distribution with odd-j(') > even-j('). This interesting observation is strongly influenced by nuclear spin statistics. PMID:25669382

  20. Production of reactive sintered nickel aluminide

    SciTech Connect

    Cooper, R.M.

    1993-01-01

    Effort over the past 3 months was directed at increasing manufacturing capacity (ball milling) and improving product quality. Orders for the powder have increased, mainly for plasma spray powders. NiAl is an excellent coat between a metal and a ceramic, and its use instead of cobalt should extending operating range for carbide tools. The feather phase in the sintered Ni[sub 3]Al was identified to be a Ni-rich phase nucleated on the grain boundaries with 10 wt % Al composition. The ductile to brittle temperature of powder extruded NiAl was found to be between 500 and 600 C, and shows a 50% elongation at 600 C.

  1. Sensitive skin and stratum corneum reactivity to household cleaning products.

    PubMed

    Goffin, V; Piérard-Franchimont, C; Piérard, G E

    1996-02-01

    Products intended for individuals with sensitive skin are being increasingly developed by formulators of household cleaning products. However, there is currently no consensus about the definition and recognition of the biological basis of sensitive skin. We sought to determine the relation between the nature of environmental threat perceived as aggressive by panelists, and the stratum corneum reactivity to household cleaning products as measured by the corneosurfametry test. Results indicate substantial differences in irritancy potential between proprietary products. Corneosurfametry data show significant differences in stratum corneum reactivity between, on the one hand, individuals with either non-sensitive skin or skin sensitive to climate/fabrics, and, on the other hand, individuals with detergent-sensitive skin. It is concluded that sensitive skin is not one single condition. Sound information in rating detergent-sensitive skin may be gained by corneosurfametry. PMID:8681562

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

    SciTech Connect

    Wang, Si-Yi; Jiang, Xiang-Xu; Wei, Xin-Pan; Lee, Shuit-Tong E-mail: yaohe@suda.edu.cn; He, Yao E-mail: yaohe@suda.edu.cn; Xu, Ting-Ting

    2014-06-16

    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.

  3. Quantum mechanical reactive scattering theory for simple chemical reactions: Recent developments in methodology and applications

    SciTech Connect

    Miller, W.H.

    1989-08-01

    It has recently been discovered that the S-matrix version of the Kohn variational principle is free of the Kohn anomalies'' that have plagued other versions and prevented its general use. This has made a major contribution to heavy particle reactive (and also to electron-atom/molecule) scattering which involve non-local (i.e., exchange) interactions that prevent solution of the coupled channel equations by propagation methods. This paper reviews the methodology briefly and presents a sample of integral and differential cross sections that have been obtained for the H + H{sub 2} {yields} H{sub 2} +H and D + H{sub 2} {yields} HD + H reactions in the high energy region (up to 1.2 eV translational energy) relevant to resonance structures reported in recent experiments. 35 refs., 11 figs.

  4. A MATLAB-based finite-element visualization of quantum reactive scattering. I. Collinear atom-diatom reactions

    SciTech Connect

    Warehime, Mick; Alexander, Millard H.

    2014-07-14

    We restate the application of the finite element method to collinear triatomic reactive scattering dynamics with a novel treatment of the scattering boundary conditions. The method provides directly the reactive scattering wave function and, subsequently, the probability current density field. Visualizing these quantities provides additional insight into the quantum dynamics of simple chemical reactions beyond simplistic one-dimensional models. Application is made here to a symmetric reaction (H+H{sub 2}), a heavy-light-light reaction (F+H{sub 2}), and a heavy-light-heavy reaction (F+HCl). To accompany this article, we have written a MATLAB code which is fast, simple enough to be accessible to a wide audience, as well as generally applicable to any problem that can be mapped onto a collinear atom-diatom reaction. The code and user's manual are available for download from http://www2.chem.umd.edu/groups/alexander/FEM.

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

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

    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.

  6. Orientation and state-selection of hydroxyl radicals by electric hexapole focusing - applications in reactive surface scattering.

    NASA Astrophysics Data System (ADS)

    Curtiss, Thomas J.; Backstrand, Kyle M.; Hain, Toby D.; Weibel, Michael A.

    1997-03-01

    Hydroxyl radicals generated in a corona-discharge free jet expansion have been focused and rotationally state-selected with an electrostatic hexapole. Tuning the hexapole resonance voltage selectively focused either of two populated |J ? M_J> states onto a scattering target, either the |3/2 3/2 3/2> state or the |3/2 3/2 1/2> state. Trajectory calculations reproduce experimental focusing spectra for OH and OD seeded in He and Ar well. We will report results from work in progress on reactive scattering studies exploring the oxygen / hydrogen / platinum catalysis system. abstract.

  7. Heavy quark production in deep-inelastic scattering at HERA.

    SciTech Connect

    Harris, B. W.; Laenen, E.; Moch, S.; Smith, J.

    1999-06-02

    We discuss two topics in the production of heavy quarks in deep-inelastic scattering: the next-to-leading order Monte-Carlo HVQDIS and the next-to-leading logarithmic resummation of soft gluon effects, including estimates of next-to-next-to-leading order corrections therefrom.

  8. Reactivities and Products of Free Radical Oxidation of Cholestadienols

    PubMed Central

    2015-01-01

    7-Dehydrocholesterol (7-DHC) is the most oxidizable lipid molecule reported to date, with a propagation rate constant for free radical peroxidation that is 200 times that of cholesterol. To better understand the high reactivity of 7-DHC and elucidate the reaction mechanism, we synthesized conjugated and skipped nonconjugated cholestadienols that would give one of the two putative pentadienyl-radical intermediates formed in 7-DHC peroxidation. The additional dienols include 6,8(9)-dienol, 5,8(14)-dienol, 6,8(14)-dienol, and the biologically important 8-dehydrocholesterol (8-DHC; 5,8(9)-dienol). We found that all of the dienols are significantly (at least 40 times) more reactive than cholesterol. Among them, dienols leading to the formation of the pentadienyl radical in ring B (termed endo-B) of the sterol are more reactive than those leading to the pentadienyl radical spanning rings B and C (termed exo-B). By comparing the oxysterol profile formed from 7-DHC and those formed from 8-DHC and 5,8(14)-dienol, products formed from abstraction of the hydrogen atoms at C-9 and C-14 (H-9 or H-14 mechanism) were clearly differentiated. When the oxidation was carried out in the presence of the good hydrogen atom donor ?-tocopherol, the oxysterol profile of 7-DHC peroxidation differed distinctly from the profile observed in the absence of the antioxidant and resembles more closely the profile observed in biological systems. This study suggests that oxidative stress and the accumulation of oxysterols should be considered as two key factors in cholesterol biosynthesis or metabolism disorders, where dienyl sterol intermediates are accumulated. PMID:24625033

  9. A novel wave packet description of electron transfer and dissociation in molecule/surface reactive scattering

    NASA Astrophysics Data System (ADS)

    Qian, Jiwen; Jacobs, Dennis C.; Tannor, David J.

    1995-12-01

    Recently reported molecular ion/surface scattering experiments [J. Chem. Phys. 100, 6791 (1994)] demonstrate that the translational and vibrational energies of incident NO+ each have a distinct influence on molecular dissociation for the NO+/GaAs(110) system. The detailed analysis of possible mechanisms suggest that the initial translational, vibrational, and rotational energies, as well as the molecule's orientation and point of impact at the surface are important in determining the dissociation probability. In this paper, a wave packet simulation of NO+/GaAs(110) scattering is performed. The emphasis in the study is on the branching ratio for production of NO, NO-, O, and O- as a function of vibrational and translational energy of the incident NO+. A novel procedure for treating the coupling of a molecular state with a band of substrate electronic states is combined with a mixed classical-quantal treatment of the nuclear motion. The simulations suggest that electron transfer and collision induced dissociation (CID) cooperate and form a vibrational coherence through which the initial vibrational state strongly influences the dissociation dynamics.

  10. Kinetic analysis of phagosomal production of reactive oxygen species.

    PubMed

    Tlili, Asma; Dupr-Crochet, Sophie; Erard, Marie; Nsse, Oliver

    2011-02-01

    Phagocytes produce large quantities of reactive oxygen species for pathogen killing; however, the kinetics and amplitude of ROS production on the level of individual phagosomes are poorly understood. This is mainly due to the lack of appropriate methods for quantitative ROS detection with microscopic resolution. We covalently attached the ROS-sensitive dye dichlorodihydrofluorescein (DCFH(2)) to yeast particles and investigated their fluorescence due to oxidation in vitro and in live phagocytes. In vitro, the dye was oxidized by H(2)O(2) plus horseradish peroxidase but also by HOCl. The latter produced a previously unrecognized oxidation product with red-shifted excitation and emission spectra and a characteristic difference in the shape of the excitation spectrum near 480 nm. Millimolar HOCl bleached the DCFH(2) oxidation products. Inside phagosomes, DCFH(2)-labeled yeast were oxidized for several minutes in a strictly NADPH oxidase-dependent manner as shown by video microscopy. Inhibition of the NADPH oxidase rapidly stopped the fluorescence increase of the particles. At least two characteristic kinetics of oxidation were distinguished and the variability of DCFH(2) oxidation in phagosomes was much larger than the variability upon oxidation in vitro. We conclude that DCFH(2)-yeast is a valuable tool to investigate the kinetics and amplitude of ROS production in individual phagosomes. PMID:21111807

  11. Enzymatic Production of Extracellular Reactive Oxygen Species by Marine Microorganisms

    NASA Astrophysics Data System (ADS)

    Diaz, J. M.; Andeer, P. F.; Hansel, C. M.

    2014-12-01

    Reactive oxygen species (ROS) serve as intermediates in a myriad of biogeochemically important processes, including cell signaling pathways, cellular oxidative stress responses, and the transformation of both nutrient and toxic metals such as iron and mercury. Abiotic reactions involving the photo-oxidation of organic matter were once considered the only important sources of ROS in the environment. However, the recent discovery of substantial biological ROS production in marine systems has fundamentally shifted this paradigm. Within the last few decades, marine phytoplankton, including diatoms of the genus Thalassiosira, were discovered to produce ample extracellular quantities of the ROS superoxide. Even more recently, we discovered widespread production of extracellular superoxide by phylogenetically and ecologically diverse heterotrophic bacteria at environmentally significant levels (up to 20 amol cell-1 hr-1), which has introduced the revolutionary potential for substantial "dark" cycling of ROS. Despite the profound biogeochemical importance of extracellular biogenic ROS, the cellular mechanisms underlying the production of this ROS have remained elusive. Through the development of a gel-based assay to identify extracellular ROS-producing proteins, we have recently found that enzymes typically involved in antioxidant activity also produce superoxide when molecular oxygen is the only available electron acceptor. For example, large (~3600 amino acids) heme peroxidases are involved in extracellular superoxide production by a bacterium within the widespread Roseobacter clade. In Thalassiosira spp., extracellular superoxide is produced by flavoproteins such as glutathione reductase and ferredoxin NADP+ reductase. Thus, extracellular ROS production may occur via secreted and/or cell surface enzymes that modulate between producing and degrading ROS depending on prevailing geochemical and/or ecological conditions.

  12. 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

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

    1980-05-01

    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.

  13. In situ reactive oxygen species production for tertiary wastewater treatment.

    PubMed

    Guitaya, La; Drogui, Patrick; Blais, Jean Franois

    2015-05-01

    The goal of this research was to develop a new approach for tertiary water treatment, particularly disinfection and removal of refractory organic compounds, without adding any chemical. Hydrogen peroxide can indeed be produced from dissolved oxygen owing to electrochemical processes. Using various current intensities (1.0 to 4.0 A), it was possible to in situ produce relatively high concentration of H2O2 with a specific production rate of 0.05??10(-5) M/min/A. Likewise, by using ultraviolet-visible absorption spectroscopy method, it was shown that other reactive oxygen species (ROS) including HO(*) radical and O3 could be simultaneously formed during electrolysis. The ROS concentration passed from 0.45??10(-5) M after 20 min of electrolysis to a concentration of 2.87??10(-5) M after 100 min of electrolysis. The disinfection and the organic matter removal were relatively high during the tertiary treatment of municipal and domestic wastewaters. More than 90 % of organic compounds (chemical oxygen demand) can be removed, whereas 99 % of faecal coliform abatement can be reached. Likewise, the process was also effective in removing turbidity (more than 90 % of turbidity was removed) so that the effluent became more and more transparent. PMID:25483973

  14. Oxidation of Reactive Nitrogen and Ozone Production in Tokyo

    NASA Astrophysics Data System (ADS)

    Fukuda, M.; Kondo, Y.; Miyazaki, Y.; Morino, Y.; Takegawa, N.; Miyakawa, T.; Komazaki, Y.; Tanimoto, H.; Yokouchi, Y.; Kanaya, Y.; McKenzie, R.; Johnston, P.

    2005-12-01

    Ground based measurements of NOx (NO + NO2), nitric acid (HNO3), particulate nitrate (NO3-), peroxyacyl nitrates (PANs), and total reactive nitrogen (NOy) were conducted in Tokyo in winter (January-February 2004), summer (July-August 2003 and 2004), and fall (October 2003). Carbon monoxide (CO), ozone (O3), non-methane hydrocarbons (NMHCs) and actinic flux were also measured during these periods. Average mixing ratios of these species and the NOx/NOy, HNO3/NOy, NO3-/NOy, and PANs/NOy ratios showed distinct diurnal-seasonal variations. The NOx/NOy ratios were 0.63-0.95 on high J(O1D) days, and 0.77-0.94 on low J(O1D) days. In summer and winter, total nitrate (TN = HNO3 + NO3-) was the dominant form of the NOx oxidation products (NOz = NOy - NOx) during the daytime on high J(O1D) days, and PANs were minor component species. The partitioning of TN was controlled mainly by temperature and the shit of the partitioning to NO3- at low temperature suppressed removal of NOy by dry deposition of HNO3. Removal rate of NOy is estimated using CO as a tracer. The estimated loss of NOy (LNOy) was largest during the daytime in summer (35%), while smallest (0%) in winter. The corrected ozone production efficiency (OPEx), which is defined as the linear regression slope of the observed Ox (= O3 + NO2) versus NOz* (= NOz + LNOy), is estimated to be 2.5. The estimated OPEx is slightly lower than those obtained in the U.S. urban air, which is probably due to lower ratios of NMHCs to NOx in this study. Possible factors controlling the OPEx will be discussed in detail.

  15. Exclusive vector meson production in muon-nucleus scattering

    SciTech Connect

    Fang, G.Y.; E665 Collaboration

    1994-02-01

    Preliminary results on the cross section ratios of exclusive incoherent {rho}{sup 0} and {phi} meson production off deuterium, carbon, calcium, and lead to that off hydrogen and coherent {rho}{sup 0} and {phi} meson production off calcium and lead to that off carbon in deep-inelastic muon-nucleon and muon-nucleus scattering are reported. The data were taken with the E665 spectrometer using the Fermilab Tevatron muon beam. The mean beam energy was 470 GeV. Increases in the cross section ratios are seen in both the elastic and quasi-elastic production as the four-momentum squared of the virtual photon increases. The results support the idea of color transparency.

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

    SciTech Connect

    Kozier, K. S.; Roubtsov, D.; Plompen, A. J. M.; Kopecky, S.

    2012-07-01

    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)

  17. Molten salt extraction of transuranic and reactive fission products from used uranium oxide fuel

    DOEpatents

    Herrmann, Steven Douglas

    2014-05-27

    Used uranium oxide fuel is detoxified by extracting transuranic and reactive fission products into molten salt. By contacting declad and crushed used uranium oxide fuel with a molten halide salt containing a minor fraction of the respective uranium trihalide, transuranic and reactive fission products partition from the fuel to the molten salt phase, while uranium oxide and non-reactive, or noble metal, fission products remain in an insoluble solid phase. The salt is then separated from the fuel via draining and distillation. By this method, the bulk of the decay heat, fission poisoning capacity, and radiotoxicity are removed from the used fuel. The remaining radioactivity from the noble metal fission products in the detoxified fuel is primarily limited to soft beta emitters. The extracted transuranic and reactive fission products are amenable to existing technologies for group uranium/transuranic product recovery and fission product immobilization in engineered waste forms.

  18. Mitochondria: Much ado about nothing? How dangerous is reactive oxygen species production??

    PubMed Central

    Holzerov, Elika; Prokisch, Holger

    2015-01-01

    For more than 50 years, reactive oxygen species have been considered as harmful agents, which can attack proteins, lipids or nucleic acids. In order to deal with reactive oxygen species, there is a sophisticated system developed in mitochondria to prevent possible damage. Indeed, increased reactive oxygen species levels contribute to pathomechanisms in several human diseases, either by its impaired defense system or increased production of reactive oxygen species. However, in the last two decades, the importance of reactive oxygen species in many cellular signaling pathways has been unraveled. Homeostatic levels were shown to be necessary for correct differentiation during embryonic expansion of stem cells. Although the mechanism is still not fully understood, we cannot only regard reactive oxygen species as a toxic by-product of mitochondrial respiration anymore. This article is part of a Directed Issue entitled: Energy Metabolism Disorders and Therapies. PMID:25666559

  19. Azimuthal angle dependence of dijet production in unpolarized hadron scattering

    SciTech Connect

    Lu Zhun; Schmidt, Ivan

    2008-08-01

    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.

  20. ? production and neutron inelastic scattering cross sections for 76Ge

    NASA Astrophysics Data System (ADS)

    Rouki, C.; Domula, A. R.; Droh, J. C.; Koning, A. J.; Plompen, A. J. M.; Zuber, K.

    2013-11-01

    The 2040.7-keV ? ray from the 69th excited state of 76Ge was investigated in the interest of Ge-based double-?-decay experiments like the Germanium Detector Array (GERDA) experiment. The predicted transition could interfere with valid 0??? events at 2039.0 keV, creating false signals in large-volume 76Ge enriched detectors. The measurement was performed with the Gamma Array for Inelastic Neutron Scattering (GAINS) at the Geel Electron Linear Accelerator (GELINA) white neutron source, using the (n,n'?) technique and focusing on the strongest ? rays originating from the level. Upper limits obtained for the production cross section of the 2040.7-keV ? ray showed no possible influence on GERDA data. Additional analysis of the data yielded high-resolution cross sections for the low-lying states of 76Ge and related ? rays, improving the accuracy and extending existing data for five transitions and five levels. The inelastic scattering cross section for 76Ge was determined for incident neutron energies up to 2.23 MeV, significantly increasing the energy range for which experimental data are available. Comparisons with model calculations using the talys code are presented indicating that accounting for the recently established asymmetric rotor structure should lead to an improved description of the data.

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

    SciTech Connect

    Winans, R. E.

    1999-01-22

    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.

  2. Testing saturation with diffractive jet production in deep inelastic scattering

    SciTech Connect

    Golec-Biernat, K.; Marquet, C.

    2005-06-01

    We analyze the dissociation of a photon in diffractive deep inelastic scattering in the kinematic regime where the diffractive mass is much bigger than the photon virtuality. We consider the dominant qqg component keeping track of the transverse momentum of the gluon which can be measured as a final-state jet. We show that the diffractive gluon-jet production cross-section is strongly sensitive to unitarity constraints. In particular, in a model with parton saturation, this cross-section is sensitive to the scale at which unitarity effects become important, the saturation scale. We argue that the measurement of diffractive jets at HERA in the limit of high diffractive mass can provide useful information on the saturation regime of QCD.

  3. Solar light-induced production of reactive oxygen species by single walled carbon nanotubes in water

    EPA Science Inventory

    Photosensitizing processes of engineered nanomaterials (ENMs) which include photo-induced production of reactive oxygen species (ROS) convert light energy into oxidizing chemical energy that mediates transformations of nanomaterials. The oxidative stress associated with ROS may p...

  4. D* production in deep inelastic scattering at HERA

    NASA Astrophysics Data System (ADS)

    Breitweg, J.; Derrick, M.; Krakauer, D.; Magill, S.; Mikunas, D.; Musgrave, B.; Repond, J.; Stanek, R.; Talaga, R. L.; Yoshida, R.; Zhang, H.; Mattingly, M. C. K.; Anselmo, F.; Antonioli, P.; Bari, G.; Basile, M.; Bellagamba, L.; Boscherini, D.; Bruni, A.; Bruni, G.; Romeo, G. Cara; Castellini, G.; Cifarelli, L.; Cindolo, F.; Contin, A.; Corradi, M.; de Pasquale, S.; Gialas, I.; Giusti, P.; Iacobucci, G.; Laurenti, G.; Levi, G.; Margotti, A.; Massam, T.; Nania, R.; Palmonari, F.; Pesci, A.; Polini, A.; Sartorelli, G.; Garcia, Y. Zamora; Zichichi, A.; Amelung, C.; Bornheim, A.; Brock, I.; Cobken, K.; Crittenden, J.; Deffner, R.; Eckert, M.; Feld, L.; Grothe, M.; Hartmann, H.; Heinloth, K.; Heinz, L.; Hilger, E.; Jakob, H.-P.; Katz, U. F.; Paul, E.; Pfeiffer, M.; Rembser, Ch.; Stamm, J.; Wedemeyer, R.; Bailey, D. S.; Campbell-Robson, S.; Cottingham, W. N.; Foster, B.; Hall-Wilton, R.; Hayes, M. E.; Heath, G. P.; Heath, H. F.; Piccioni, D.; Roff, D. G.; Tapper, R. J.; Arneodo, M.; Ayad, R.; Capua, M.; Garfagnini, A.; Iannotti, L.; Schioppa, M.; Susinno, G.; Kim, J. Y.; Lee, J. H.; Lim, I. T.; Pac, M. Y.; Caldwell, A.; Cartiglia, N.; Jing, Z.; Liu, W.; Parsons, J. A.; Ritz, S.; Sampson, S.; Sciulli, F.; Straub, P. B.; Zhu, Q.; Borzemski, P.; Chwastowski, J.; Eskreys, A.; Jakubowski, Z.; Przybycie?, M. B.; Zachara, M.; Zawiejski, L.; Adamczyk, L.; Bednarek, B.; Jele?, K.; Kisielewska, D.; Kowalski, T.; Przybycie?, M.; Rulikowska-Zar?bska, E.; Suszycki, L.; Zajac, J.; Duli?ski, Z.; Kota?ski, A.; Abbiendi, G.; Bauerdick, L. A. T.; Behrens, U.; Beier, H.; Bienlein, J. K.; Cases, G.; Deppe, O.; Desler, K.; Drews, G.; Fricke, U.; Gilkinson, D. J.; Glasman, C.; Gttlicher, P.; Groe-Knetter, J.; Haas, T.; Hain, W.; Hasell, D.; Johnson, K. F.; Kasemann, M.; Koch, W.; Ktz, U.; Kowalski, H.; Labs, J.; Lindemann, L.; Lhr, B.; Lwe, M.; Ma?czak, O.; Milewski, J.; Monteiro, T.; Ng, J. S. T.; Notz, D.; Ohrenberg, K.; Park, I. H.; Pellegrino, A.; Pelucchi, F.; Piotrzkowski, K.; Roco, M.; Rohde, M.; Roldn, J.; Ryan, J. J.; Savin, A. A.; Schneekloth, U.; Selonke, F.; Surrow, B.; Tassi, E.; Vo, T.; Westphal, D.; Wolf, G.; Wollmer, U.; Youngman, C.; ?arnecki, A. F.; Zeuner, W.; Burow, B. D.; Grabosch, H. J.; Meyer, A.; Schlenstedt, S.; Barbagli, G.; Gallo, E.; Pelfer, P.; Maccarrone, G.; Votano, L.; Bamberger, A.; Eisenhardt, S.; Markun, P.; Trefzger, T.; Wlfle, S.; Bromley, J. T.; Brook, N. H.; Bussey, P. J.; Doyle, A. T.; Saxon, D. H.; Sinclair, L. E.; Strickland, E.; Utley, M. L.; Waugh, R.; Wilson, A. S.; Bohnet, I.; Gendner, N.; Holm, U.; Meyer-Larsen, A.; Salehi, H.; Wick, K.; Gladilin, L. K.; Horstmann, D.; Kira, D.; Klanner, R.; Lohrmann, E.; Poelz, G.; Schott, W.; Zetsche, F.; Bacon, T. C.; Butterworth, I.; Cole, J. E.; Harris, V. L.; Howell, G.; Hung, B. H. Y.; Lamberti, L.; Long, K. R.; Miller, D. B.; Pavel, N.; Prinias, A.; Sedgbeer, J. K.; Sideris, D.; Whitfield, A. F.; Mallik, U.; Wang, S. M.; Wu, J. T.; Cloth, P.; Filges, D.; Fleck, J. I.; Ishii, T.; Kuze, M.; Nakao, M.; Tokushuku, K.; Yamada, S.; Yamazaki, Y.; An, S. H.; Lee, S. B.; Nam, S. W.; Park, H. S.; Park, S. K.; Barreiro, F.; Fernndez, J. P.; Garca, G.; Graciani, R.; Hernndez, J. M.; Hervs, L.; Labarga, L.; Martnez, M.; del Peso, J.; Puga, J.; Terrn, J.; de Trocniz, J. F.; Corriveau, F.; Hanna, D. S.; Hartmann, J.; Hung, L. W.; Lim, J. N.; Murray, W. N.; Ochs, A.; Riveline, M.; Stairs, D. G.; St-Laurent, M.; Ullmann, R.; Tsurugai, T.; Bashkirov, V.; Dolgoshein, B. A.; Stifutkin, A.; Bashindzhagyan, G. L.; Ermolov, P. F.; Golubkov, Yu. A.; Khein, L. A.; Korotkova, N. A.; Korzhavina, I. A.; Kuzmin, V. A.; Lukina, O. Yu.; Proskuryakov, A. S.; Shcheglova, L. M.; Shumilin, A. V.; Solomin, A. N.; Zotkin, S. A.; Bokel, C.; Botje, M.; Brmmer, N.; Chlebana, F.; Engelen, J.; Kooijman, P.; Kruse, A.; van Sighem, A.; Tiecke, H.; Verkerke, W.; Vossebeld, J.; Vreeswijk, M.; Wiggers, L.; de Wolf, E.; Acosta, D.; Bylsma, B.; Durkin, L. S.; Gilmore, J.; Ginsburg, C. M.; Kim, C. L.; Ling, T. Y.; Nylander, P.; Romanowski, T. A.; Blaikley, H. E.; Cashmore, R. J.; Cooper-Sarkar, A. M.; Devenish, R. C. E.; Edmonds, J. K.; Harnew, N.; Lancaster, M.; McFall, J. D.; Nath, C.; Noyes, V. A.; Quadt, A.; Ruske, O.; Tickner, J. R.; Uijterwaal, H.; Walczak, R.; Waters, D. S.; Bertolin, A.; Brugnera, R.; Carlin, R.; dal Corso, F.; Dosselli, U.; Limentani, S.; Morandin, M.; Posocco, M.; Stanco, L.; Stroili, R.; Voci, C.; Bulmahn, J.; Feild, R. G.; Oh, B. Y.; Okrasi?ski, J. R.; Whitmore, J. J.; Iga, Y.; D'Agostini, G.; Marini, G.; Nigro, A.; Raso, M.; Hart, J. C.; McCubbin, N. A.; Shah, T. P.; Barberis, E.; Dubbs, T.; Heusch, C.; van Hook, M.; Lockman, W.; Rahn, J. T.; Sadrozinski, H. F.-W.; Seiden, A.; Williams, D. C.; Schwarzer, O.

    1997-02-01

    This paper presents measurements of D*+/- production in deep inelastic scattering from collisions between 27.5 GeV positrons and 820 GeV protons. The data have been taken with the ZEUS detector at HERA. The decay channel D*+ -> (D0 -> K- ?+) ?+ (+c.c.) has been used in the study. The e+p cross section for inclusive D*+/- production with 5 < Q2 < 100 GeV2 and y < 0.7 is 5.3 +/- 1.0 +/- 0.8 nb in the kinematic region 1.3 < pT(D*+/-) < 9.0 GeV and ?(D*+/-) < 1.5. Differential cross sections as functions of pT(D*+/-), ?(D*+/-), W and Q2 are compared with next-to-leading order QCD calculations based on the photon-gluon fusion production mechanism. After an extrapolation of the cross section to the full kinematic region in pT(D*+/-) and ?(D*+/-), the charm contribution Fcc2 (x, Q2) to the proton structure function is determined for Bjorken x between 2.10-4 and 5.10-3.

  5. Fullerol-sensitized production of reactive oxygen species in aqueous solution.

    PubMed

    Pickering, K D; Wiesner, M R

    2005-03-01

    The relative production rate of reactive oxygen in aqueous solution sensitized by fullerol (a polyhydroxylated, water-soluble form of the fullerene C60) was measured and compared to known reactive oxygen sensitizers using an oxygen consumption method. The solutions were irradiated by polychromatic visible and ultraviolet light. Reactive oxygen species were generated under both visible and ultraviolet light sources. The greatest rates of oxygen consumption were observed at acidic pH. We show for the first time evidence of both singlet oxygen and superoxide production by fullerol under both UV and polychromatic light sources. PMID:15787378

  6. Atmospheric OH reactivity in central London: observations, model predictions and estimates of in situ ozone production

    NASA Astrophysics Data System (ADS)

    Whalley, L. K.; Stone, D.; Bandy, B.; Dunmore, R.; Hamilton, J. F.; Hopkins, J.; Lee, J. D.; Lewis, A. C.; Heard, D. E.

    2015-11-01

    Near-continuous measurements of OH reactivity in the urban background atmosphere of central London during the summer of 2012 are presented. OH reactivity behaviour is seen to be broadly dependent on airmass origin with the highest reactivity and the most pronounced diurnal profile observed when air had passed over central London to the East, prior to measurement. Averaged over the entire observation period of 26 days, OH reactivity peaked at ~ 27 s-1 in the morning with a minimum of ~ 15 s-1 during the afternoon. A maximum OH reactivity of 116 s-1 was recorded on one day during morning rush hour. A detailed box model using the Master Chemical Mechanism was used to calculate OH reactivity, and was constrained with an extended measurement dataset of volatile organic compounds (VOCs) derived from GC-FID and a two-dimensional GC instrument which included heavier molecular weight (up to C12) aliphatic VOCs, oxygenated VOCs and the biogenic VOCs of α pinene and limonene. Comparison was made between observed OH reactivity and modelled OH reactivity using (i) a standard suite of VOC measurements (C2-C8 hydrocarbons and a small selection of oxygenated VOCs) and (ii) a more comprehensive inventory including species up to C12. Modelled reactivities were lower than those measured (by 33 %) when only the reactivity of the standard VOC suite was considered. The difference between measured and modelled reactivity was improved, to within 15 %, if the reactivity of the higher VOCs (≥ C9) was also considered, with the reactivity of the biogenic compounds of α pinene and limonene and their oxidation products almost entirely responsible for this improvement. Further improvements in the model's ability to reproduce OH reactivity (to within 6 %) could be achieved if the reactivity and degradation mechanism of unassigned two-dimensional GC peaks were estimated. Neglecting the contribution of the higher VOCs (≥ C9) (particularly α pinene and limonene) and model-generated intermediates worsened the agreement between modelled and observed OH concentrations (by 41 %) and the magnitude of in situ ozone production calculated from the production of RO2 was significantly lower (60 %). This work highlights that any future ozone abatement strategies should consider the role that biogenic emissions play alongside anthropogenic emissions in influencing London's air quality.

  7. Atmospheric OH reactivity in central London: observations, model predictions and estimates of in situ ozone production

    NASA Astrophysics Data System (ADS)

    Whalley, Lisa K.; Stone, Daniel; Bandy, Brian; Dunmore, Rachel; Hamilton, Jacqueline F.; Hopkins, James; Lee, James D.; Lewis, Alastair C.; Heard, Dwayne E.

    2016-02-01

    Near-continuous measurements of hydroxyl radical (OH) reactivity in the urban background atmosphere of central London during the summer of 2012 are presented. OH reactivity behaviour is seen to be broadly dependent on air mass origin, with the highest reactivity and the most pronounced diurnal profile observed when air had passed over central London to the east, prior to measurement. Averaged over the entire observation period of 26 days, OH reactivity peaked at ˜ 27 s-1 in the morning, with a minimum of ˜ 15 s-1 during the afternoon. A maximum OH reactivity of 116 s-1 was recorded on one day during morning rush hour. A detailed box model using the Master Chemical Mechanism was used to calculate OH reactivity, and was constrained with an extended measurement data set of volatile organic compounds (VOCs) derived from a gas chromatography flame ionisation detector (GC-FID) and a two-dimensional GC instrument which included heavier molecular weight (up to C12) aliphatic VOCs, oxygenated VOCs and the biogenic VOCs α-pinene and limonene. Comparison was made between observed OH reactivity and modelled OH reactivity using (i) a standard suite of VOC measurements (C2-C8 hydrocarbons and a small selection of oxygenated VOCs) and (ii) a more comprehensive inventory including species up to C12. Modelled reactivities were lower than those measured (by 33 %) when only the reactivity of the standard VOC suite was considered. The difference between measured and modelled reactivity was improved, to within 15 %, if the reactivity of the higher VOCs (⩾ C9) was also considered, with the reactivity of the biogenic compounds of α-pinene and limonene and their oxidation products almost entirely responsible for this improvement. Further improvements in the model's ability to reproduce OH reactivity (to within 6 %) could be achieved if the reactivity and degradation mechanism of unassigned two-dimensional GC peaks were estimated. Neglecting the contribution of the higher VOCs (⩾ C9) (particularly α-pinene and limonene) and model-generated intermediates increases the modelled OH concentrations by 41 %, and the magnitude of in situ ozone production calculated from the production of RO2 was significantly lower (60 %). This work highlights that any future ozone abatement strategies should consider the role that biogenic emissions play alongside anthropogenic emissions in influencing London's air quality.

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

    SciTech Connect

    Troshin, S. M.

    2013-04-15

    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.

  9. Products of rectangular random matrices: Singular values and progressive scattering

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

    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.

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

    PubMed

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

    2013-11-01

    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

  11. Gas-Microjet Reactive Scattering: Collisions of HCl and DCl with Cool Salty Water.

    PubMed

    Faust, Jennifer A; Sobyra, Thomas B; Nathanson, Gilbert M

    2016-02-18

    Liquid microjets provide a powerful means to investigate reactions of gases with salty water in vacuum while minimizing gas-vapor collisions. We use this technique to explore the fate of gaseous HCl and DCl molecules impinging on 8 molal LiCl and LiBr solutions at 238 K. The experiments reveal that HCl or DCl evaporate infrequently if they become thermally accommodated at the surface of either solution. In particular, we observe minimal thermal desorption of HCl following HCl collisions and no distinct evidence for rapid, interfacial DCl?HCl exchange following DCl collisions. These results imply that surface thermal motions are not generally strong enough to propel momentarily trapped HCl or DCl back into the gas phase before they ionize and disappear into solution. Instead, only HCl and DCl molecules that scatter directly from the surface escape entry. These recoiling molecules transfer less energy upon collision to LiBr/H2O than to LiCl/H2O, reflecting the heavier mass of Br(-) than of Cl(-) in the interfacial region. PMID:26828574

  12. Higher-order split operator schemes for solving the Schrödinger equation in the time-dependent wave packet method: applications to triatomic reactive scattering calculations.

    PubMed

    Sun, Zhigang; Yang, Weitao; Zhang, Dong H

    2012-02-14

    The efficiency of the numerical propagators for solving the time-dependent Schrödinger equation in the wave packet approach to reactive scattering is of vital importance. In this Perspective, we first briefly review the propagators used in quantum reactive scattering calculations and their applications to triatomic reactions. Then we present a detailed comparison of about thirty higher-order split operator propagators for solving the Schrödinger equation with their applications to the wave packet evolution within a one-dimensional Morse potential, and the total reaction probability calculations for the H + HD, H + NH, H + O(2), and F + HD reactions. These four triatomic reactions have quite different dynamic characteristics and thus provide a comprehensive picture of the relative advantages of these higher-order propagation methods for describing reactive scattering dynamics. Our calculations reveal that the most often used second-order split operator method is typically more efficient for a direct reaction, particularly for those involving flat potential energy surfaces. However, the optimal higher-order split operator methods are more suitable for a reaction with resonances and intermediate complexes or a reaction experiencing potential energy surface with fluctuations of considerable amplitude. Three 4th-order and one 6th-order split operator methods, which are most efficient for solving reactive scattering in various conditions among the tested ones, are recommended for general applications. In addition, a brief discussion on the relative performance between the Chebyshev real wave packet method and the split operator method is given. The results in this Perspective are expected to stimulate more applications of (high-order) split operators to the quantum reactive scattering calculation and other related problems. PMID:22234283

  13. State-to-state dynamics of the H{sup *}(n) + HD ? D{sup *}(n{sup ?}) + H{sub 2} reactive scattering

    SciTech Connect

    Yu, Shengrui; Su, Shu; Dai, Dongxu; Yuan, Kaijun E-mail: xmyang@dicp.ac.cn; Yang, Xueming E-mail: xmyang@dicp.ac.cn

    2014-01-21

    The state-to-state dynamics of the H{sup *}(n) + HD ? D{sup *}(n{sup ?}) + H{sub 2} reactive scattering at the collision energy of 0.5 eV have been carried out for the first time by using H-atom Rydberg tagging time-of-flight technique. Experimental results show that the angular distribution of the total H{sub 2} products presents clearly forward-backward asymmetric, which considerably differs from that of the corresponding H{sup +} + HD ? D{sup +} + H{sub 2} reaction predicted by previously theoretical calculations. Such disagreement between these two processes suggests that the Fermi independent-collider model is also not valid in describing the dynamics of isotopic variants of the H{sup *} + H{sub 2} reaction. The rotational state distribution of the H{sub 2} products demonstrates a saw-toothed distribution with odd-j{sup ?} > even-j{sup ?}. This interesting observation is strongly influenced by nuclear spin statistics.

  14. Positronium beam production and scattering cross-sections

    NASA Astrophysics Data System (ADS)

    Leslie, Dawn Elizabeth

    In this work, the efficiency for the production of a monoenergetic positronium beam via the charge-exchange reaction of a positron beam in a gaseous target has been determined for molecular hydrogen and molecular nitrogen. In the case of molecular nitrogen, it has been found that the energy range over which a useful intensity of collimated positronium may be produced can be extended to 250eV, 100eV higher than previously achieved. This should enable measurements of the total and partial positronium cross-sections at correspondingly higher energies, where target inelastic effects are expected to be significant A recent measurement of the integrated positronium formation cross-section for xenon found a larger yield of positronium atoms compared to the other noble gases. A shoulder was also seen 10eV above the peak and it was suggested that this might be due to the production of positronium in an excited state. These findings have provided an incentive to investigate the collimated positronium production efficiency from xenon, which has been found to be surprisingly low. The quantum state of the beam atoms has also been found to be dominantly ground state. Possible reasons for these findings are discussed Total cross-sections for positronium-gas scattering have been extracted from the measurements of the positronium beam production efficiency for both molecular nitrogen and xenon. These quantities have also been determined directly by measuring the intensity of the positronium beam transmitted through a gas cell via the Beer-Lambert Law. A good consistency is found between the values obtained using this method and those determined indirectly. Recently, measurements have been made of the absolute integrated cross-section for the fragmentation of positronium in collision with helium atoms, along with the longitudinal energy distributions of the residual positrons in the energy range -Ep/=13-33eV. Measurements of the latter indicate a peak close to half the residual positronium energy, suggesting that they continue to move in a correlated fashion with the emitted electrons. In the present work, these results have been confirmed using a different method, which enables the energy range of investigation to be extended both to higher and lower values. Preliminary results have also been obtained at Epx=60eV for the ejected positrons and for the ejected electrons at Ep/= 33eV.

  15. Production of C-reactive protein by human lymphocytes

    SciTech Connect

    Kuta, A.E.; Baum, L.L.

    1986-03-01

    C-reactive protein (CRP) is a major acute phase serum protein in humans; it is detectable at very high concentrations during infection and tissue trauma. This protein is a pentame composed of five identical, 21,500 MW subunits. CRP is detectable on the surface of approximately 4% of normal peripheral blood lymphocytes (PBL). CRP binds its physiological ligands in a Ca/sup + +/ dependent manner; removal of Ca/sup + +/ does not alter the expression of CRP on the lymphocyte surface. Recently, investigators in this laboratory reported substantial inhibition of natural killer cell (NK) activity with anti-CRP antibodies. The following studies were undertaken to determine the origin of surface-CRP (S-CRP) found on normal PBL. Cells were incubated in methionine-free DMEM supplemented with /sup 35/S-methionine. Cells were lysed and subjected to immunoprecipitation with anti-CRP and Staphylococcus aureus; immunoprecipitates were analyzed by SDS-PAGE and autoradiography. Data presented here suggested that lymphocytes, in particular, LGL produce small amounts of CRP and express it on their surface. Lymphocytes do not appear to secrete CRP since no CRP could be detected in culture supernatants. In addition, preliminary evidence indicates that peripheral blood monocytes produce no detectable CRP. Present studies utilizing Northern blot analysis are underway in order to detect CRP-mRNA.

  16. Towards a specific reaction parameter density functional for reactive scattering of H{sub 2} from Pd(111)

    SciTech Connect

    Boereboom, J. M.; Wijzenbroek, M.; Somers, M. F.; Kroes, G. J.

    2013-12-28

    Recently, an implementation of the specific reaction parameter (SRP) approach to density functional theory (DFT) was used to study several reactive scattering experiments of H{sub 2} on Cu(111). It was possible to obtain chemical accuracy (1 kcal/mol ? 4.2 kJ/mol), and therefore, accurately model this paradigmatic example of activated H{sub 2} dissociation on a metal surface. In this work, the SRP-DFT methodology is applied to the dissociation of hydrogen on a Pd(111) surface, in order to test whether the SRP-DFT approach is also applicable to non-activated H{sub 2}-metal systems. In the calculations, the BornOppenheimer static surface approximations are used. A comparison to molecular beam sticking experiments, performed at incidence energies ?125 meV, on H{sub 2} + Pd(111) suggested the PBE-vdW [where the Perdew, Burke, and Ernzerhof (PBE) correlation is replaced by van der Waals correlation] functional as a candidate SRP density functional describing the reactive scattering of H{sub 2} on Pd(111). Unfortunately, quantum dynamics calculations are not able to reproduce the molecular beam sticking results for incidence energies <125 meV. From a comparison to initial state-resolved (degeneracy averaged) sticking probabilities it seems clear that for H{sub 2} + Pd(111) dynamic trapping and steering effects are important, and that these effects are not yet well modeled with the potential energy surfaces considered here. Applying the SRP-DFT method to systems where H{sub 2} dissociation is non-activated remains difficult. It is suggested that a density functional that yields a broader barrier distribution and has more non-activated pathways than PBE-vdW (i.e., non-activated dissociation at some sites but similarly high barriers at the high energy end of the spectrum) should allow a more accurate description of the available experiments. Finally, it is suggested that new and better characterized molecular beam sticking experiments be done on H{sub 2} + Pd(111), to facilitate the development of a more accurate theoretical description of this system.

  17. Reactive Oxygen Production Induced by the Gut Microbiota: Pharmacotherapeutic Implications

    PubMed Central

    Jones, R.M.; Mercante, J.W.; Neish, A.S.

    2014-01-01

    The resident prokaryotic microbiota of the mammalian intestine influences diverse homeostatic functions, including regulation of cellular growth, maintenance of barrier function, and modulation of immune responses. However, it is unknown how commensal prokaryotic organisms mechanistically influence eukaryotic signaling networks. Recent data has demonstrated that gut epithelia contacted by enteric commensal bacteria rapidly generate reactive oxygen species (ROS). While the induced generation of ROS via stimulation of formyl peptide receptors is a cardinal feature of the cellular response of phagocytes to pathogenic or commensal bacteria, evidence is accumulating that ROS are also similarly elicited in other cell types, including intestinal epithelia, in response to microbial signals. Additionally, ROS have been shown to serve as critical second messengers in multiple signal transduction pathways stimulated by proinflammatory cytokines and growth factors. This physiologically-generated ROS is known to participate in cellular signaling via the rapid and transient oxidative inactivation of a defined class of sensor proteins bearing oxidant-sensitive thiol groups. These proteins include tyrosine phosphatases that serve as regulators of MAP kinase pathways, cytoskeletal dynamics, as well as components involved in control of ubiquitination-mediated NF-κB activation. Consistently, microbial-elicited ROS has been shown to mediate increased cellular proliferation and motility and to modulate innate immune signaling. These results demonstrate how enteric microbiota influence regulatory networks of the mammalian intestinal epithelia. We hypothesize that many of the known effects of the normal microbiota on intestinal physiology, and potential beneficial effects of candidate probiotic bacteria, may be at least partially mediated by this ROS-dependent mechanism. PMID:22360484

  18. Chemical Characterization and Reactivity of Fuel-Oxidizer Reaction Product

    NASA Technical Reports Server (NTRS)

    David, Dennis D.; Dee, Louis A.; Beeson, Harold D.

    1997-01-01

    Fuel-oxidizer reaction product (FORP), the product of incomplete reaction of monomethylhydrazine and nitrogen tetroxide propellants prepared under laboratory conditions and from firings of Shuttle Reaction Control System thrusters, has been characterized by chemical and thermal analysis. The composition of FORP is variable but falls within a limited range of compositions that depend on three factors: the fuel-oxidizer ratio at the time of formation; whether the composition of the post-formation atmosphere is reducing or oxidizing; and the reaction or post-reaction temperature. A typical composition contains methylhydrazinium nitrate, ammonium nitrate, methylammonium nitrate, and trace amounts of hydrazinium nitrate and 1,1-dimethylhydrazinium nitrate. Thermal decomposition reactions of the FORP compositions used in this study were unremarkable. Neither the various compositions of FORP, the pure major components of FORP, nor mixtures of FORP with propellant system corrosion products showed any unusual thermal activity when decomposed under laboratory conditions. Off-limit thruster operations were simulated by rapid mixing of liquid monomethylhydrazine and liquid nitrogen tetroxide in a confined space. These tests demonstrated that monomethylhydrazine, methylhydrazinium nitrate, ammonium nitrate, or Inconel corrosion products can induce a mixture of monomethylhydrazine and nitrogen tetroxide to produce component-damaging energies. Damaging events required FORP or metal salts to be present at the initial mixing of monomethylhydrazine and nitrogen tetroxide.

  19. PRODUCTION OF STARCH GRAFT COPOLYMERS USING REACTIVE EXTRUSION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is considerable interest in the use of starch graft copolymers for applications as hydrogels, controlled release, and superabsorbents which involve contact with water. Typical production methods use batch processess at relatively low solids content, which produce large amounts of ungrafted ho...

  20. Reactant coordinate based state-to-state reactive scattering dynamics implemented on graphical processing units.

    PubMed

    Zhang, Pei-Yu; Han, Ke-Li

    2014-10-01

    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

  1. Atmospheric emission of reactive nitrogen during biofuel ethanol production.

    PubMed

    Machado, Cristine M D; Cardoso, Arnaldo A; Allen, Andrew G

    2008-01-15

    This paper evaluates emissions to the atmosphere of biologically available nitrogen compounds in a region characterized by intensive sugar cane biofuel ethanol production. Large emissions of NH3 and NOx, as well as particulate nitrate and ammonium, occur at the harvest when the crop is burned, with the amount of nitrogen released equivalent to approximately 35% of annual fertilizer-N application. Nitrogen oxides concentrations show a positive association with fire frequency, indicating that biomass burning is a major emission source, with mean concentrations of NOx doubling in the dry season relative to the wetseason. During the dry season biomass burning is a source of NH3, with other sources (wastes, soil, biogenic) predominant during the wet season. Estimated NO2-N, NH3-N, NO3- -N and NH4+ -N emission fluxes from sugar cane burning in a planted area of ca. 2.2 x 10(6) ha are 11.0, 1.1, 0.2, and 1.2 Gg N yr(-1), respectively. PMID:18284134

  2. Biodiesel production from integration between reaction and separation system: reactive distillation process.

    PubMed

    da Silva, Nvea de Lima; Santander, Carlos Mario Garcia; Batistella, Csar Benedito; Filho, Rubens Maciel; Maciel, Maria Regina Wolf

    2010-05-01

    Biodiesel is a clean burning fuel derived from a renewable feedstock such as vegetable oil or animal fat. It is biodegradable, non-inflammable, non-toxic, and produces lesser carbon monoxide, sulfur dioxide, and unburned hydrocarbons than petroleum-based fuel. The purpose of the present work is to present an efficient process using reactive distillation columns applied to biodiesel production. Reactive distillation is the simultaneous implementation of reaction and separation within a single unit of column. Nowadays, it is appropriately called "Intensified Process". This combined operation is especially suited for the chemical reaction limited by equilibrium constraints, since one or more of the products of the reaction are continuously separated from the reactants. This work presents the biodiesel production from soybean oil and bioethanol by reactive distillation. Different variables affect the conventional biodiesel production process such as: catalyst concentration, reaction temperature, level of agitation, ethanol/soybean oil molar ratio, reaction time, and raw material type. In this study, the experimental design was used to optimize the following process variables: the catalyst concentration (from 0.5 wt.% to 1.5 wt.%), the ethanol/soybean oil molar ratio (from 3:1 to 9:1). The reactive column reflux rate was 83 ml/min, and the reaction time was 6 min. PMID:20221864

  3. Quantum state-resolved reactive scattering of F+H2 in supersonic jets: Nascent HF(v,J) rovibrational distributions via IR laser direct absorption methods

    NASA Astrophysics Data System (ADS)

    Chapman, William B.; Blackmon, Brad W.; Nizkorodov, Sergey; Nesbitt, David J.

    1998-12-01

    Supersonically cooled discharge radical atom sources are combined with high-sensitivity IR absorption methods to investigate state-to-state reactive scattering of F+n-H2→HF(v,J)+H in low-density crossed supersonic jets at center-of-mass collision energies of 2.4(6) kcal/mole. The product HF(v,J) is probed with full vibrational and rotational quantum state selectivity via direct absorption of a single mode (Δν≈0.0001 cm-1), tunable F-center laser in the Δv=1 fundamental manifold with near shot noise limited detection levels of 108molecules/cm3/quantum state per pulse. The high absorption sensitivity, long mean free path lengths, and low-density conditions in the intersection region permit collision-free HF(v,J) rovibrational product state distributions to be extracted for the first time. Summed over all rotational levels, the HF vibrational branching ratios are 27.0(5)%, 54.2(23)%, 18.8(32)%, and <2(2)%, respectively, into vHF=3:2:1:0. The nascent vibrational distributions are in good agreement with rotationally unresolved crossed-beam studies of Neumark et al. [J. Chem. Phys. 82, 3045 (1985)], as well as with full quantum close-coupled calculations of Castillo and Manolopoulos [J. Chem. Phys. 104, 6531 (1996)] on the lowest adiabatic F+H2 potential surface of Stark and Werner [J. Chem. Phys. 104, 6515 (1996)]. At a finer level of quantum state resolution, the nascent rotational distributions match reasonably well with full quantum theoretical predictions, improving on the level of agreement between theory and experiment from early arrested relaxation studies. Nevertheless, significant discrepancies still exist between the fully quantum state-resolved experiment and theory, especially for the highest energetically allowed rotational levels.

  4. Positronium Production and Scattering below Its Breakup Threshold

    NASA Astrophysics Data System (ADS)

    Brawley, S. J.; Fayer, S. E.; Shipman, M.; Laricchia, G.

    2015-11-01

    Recent findings on the similarity between electron and positronium scattering at the same velocity [Brawley et al., Science 330, 789 (2010)] have guided us towards the realization of a detectable flux of positronium atoms at beam energies five times lower than previously obtained, enabling total cross sections to be measured in the energy range (1 - 7 ) eV for the first time. In collision with Ar and Xe, the total cross sections of positronium are found to be smallest at the lowest energy probed, approaching those of the Ramsauer-Townsend minima for electron projectiles. Additional structure has been observed in the case of positronium scattering at incident energies around 5 eV.

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

    PubMed Central

    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

    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

  6. Mitochondrial complex I inhibitor rotenone induces apoptosis through enhancing mitochondrial reactive oxygen species production.

    PubMed

    Li, Nianyu; Ragheb, Kathy; Lawler, Gretchen; Sturgis, Jennie; Rajwa, Bartek; Melendez, J Andres; Robinson, J Paul

    2003-03-01

    Inhibition of mitochondrial respiratory chain complex I by rotenone had been found to induce cell death in a variety of cells. However, the mechanism is still elusive. Because reactive oxygen species (ROS) play an important role in apoptosis and inhibition of mitochondrial respiratory chain complex I by rotenone was thought to be able to elevate mitochondrial ROS production, we investigated the relationship between rotenone-induced apoptosis and mitochondrial reactive oxygen species. Rotenone was able to induce mitochondrial complex I substrate-supported mitochondrial ROS production both in isolated mitochondria from HL-60 cells as well as in cultured cells. Rotenone-induced apoptosis was confirmed by DNA fragmentation, cytochrome c release, and caspase 3 activity. A quantitative correlation between rotenone-induced apoptosis and rotenone-induced mitochondrial ROS production was identified. Rotenone-induced apoptosis was inhibited by treatment with antioxidants (glutathione, N-acetylcysteine, and vitamin C). The role of rotenone-induced mitochondrial ROS in apoptosis was also confirmed by the finding that HT1080 cells overexpressing magnesium superoxide dismutase were more resistant to rotenone-induced apoptosis than control cells. These results suggest that rotenone is able to induce apoptosis via enhancing the amount of mitochondrial reactive oxygen species production. PMID:12496265

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

    PubMed

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

    2014-10-20

    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

  8. Heavy quark production in deep inelastic electron-nucleus scattering

    SciTech Connect

    Goncalves, V. P.; Kugeratski, M. S.; Navarra, F. S.

    2010-06-15

    Heavy quark production has been very well studied over the last years both theoretically and experimentally. Theory has been used to study heavy quark production in ep collisions at HERA, in pp collisions at Tevatron and RHIC, in pA and dA collisions at RHIC, and in AA collisions at CERN-SPS and RHIC. However, to the best of our knowledge, heavy quark production in eA has received almost no attention. With the possible construction of a high energy electron-ion collider, updated estimates of heavy quark production are needed. We address the subject from the perspective of saturation physics and compute the heavy quark production cross section with the dipole model. We isolate shadowing and nonlinear effects, showing their impact on the charm structure function and on the transverse momentum spectrum.

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

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.

    1994-01-01

    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.

  10. Nuclear A dependence of exclusive vector meson production in muon scattering

    SciTech Connect

    Schellman, H.; E665 Collaboration

    1994-07-01

    Results on exclusive vector meson production from Fermilab muon scattering experiment E665 are presented. The {Alpha} dependence of exclusive vector meson production is studied as a function of Q{sup 2}. The data show a significant change in the dependence on {Alpha} at higher values of Q{sup 2}. The observed behavior is consistent with the idea of color transparency.

  11. Development of a charged-coupled device-based light-scattering instrument for the detection of C-reactive protein using particle-enhanced immunoassay.

    PubMed

    Liow, E W; Keay, P J; Wang, R Y; Holownia, P; Price, C P

    2001-01-01

    A novel light-scattering instrument has been developed for rapid detection of immunoreactions in test latex particle-enhanced immunoassays. The detector consists of a flat-field grating and a charge-coupled device mounted on a rotating platform, and the detector measures a continuous spectrum from 350 nm to 735 nm at 440 polar angles with a resolution of 0.5 degrees. Optimal detection for rates of immunoreaction were determined by intensity of scattered light at different angles. Instrumental precisions were all shown to fall within 5% of the target relative standard deviation limits. The accuracy of the instrument was confirmed using monodispersed latex particles of known size and shape. The initial results showed the possibility of a sensitive and accurate detection of C-reactive protein throughout the range of clinical interest, thus demonstrating a significant potential for biomedical applications. PMID:11233307

  12. Feline mesenchymal stem cells and supernatant inhibit reactive oxygen species production in cultured feline neutrophils.

    PubMed

    Mumaw, Jennifer L; Schmiedt, Chad W; Breidling, Sarah; Sigmund, Alex; Norton, Natalie A; Thoreson, Merrilee; Peroni, John F; Hurley, David J

    2015-12-01

    Feline bone marrow-derived MSCs (BMMSCs), adipose-derived MSCs (AMSCs) and fibroblasts (FBs) were isolated and cultured. Tri-lineage differentiation assays and flow cytometry were used to characterize MSCs. Neutrophils (NPs) were isolated from whole blood and the NPs production of reactive oxygen reactive oxygen species (ROS) was measured. NPs were cultured alone, with MSC culture supernatant (SN), BMMSCs or AMSCs. NPs incubated with BMMSCs had significantly lower ROS production than NPs incubated with AMSCs (p=0.0006) or FB (p<0.0001); NPs ROS production significantly decreased with increasing BMMSC cell number (p=0.0023) and significantly increased with NPs were incubated with FB compared to BMMSC (p=0.0003). Both BMMSC SN and AMSC SN had statistically significantly lower ROS production than FB SN when incubated with NPs (both p<0.0001). ROS production was significantly reduced with increased fractions of SN from BMMSCs (p=0.0467) and AMSCs (p=0.0017). PMID:26679797

  13. Catalytic reactive separation system for energy-efficient production of cumene

    DOEpatents

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

    2009-07-28

    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.

  14. Nuclear elastic scattering effects on fusion product transport in compact tori

    SciTech Connect

    DeVeaux, J.; Greenspan, E.; Miley, G.H.

    1980-01-01

    This paper seeks to advance previous work including the effects of nuclear elastic scattering (NES) on fusion-product transport. We have found that NES may dominate the slowing-down process for high-temperature, advance-fuel plasmas which burn Cat.D or D-/sup 3/He. A modified version of the Monte Carlo fusion product transport code, MCFRM, was used to evaluate the effects of NES on discrete fusion-product orbits in the FRM.

  15. Coherent pion production by neutrino scattering off nuclei

    SciTech Connect

    Kartavtsev, A.; Paschos, E. A.; Gounaris, G. J.

    2006-09-01

    The main part of coherent pion production by neutrinos on nuclei is essentially determined by partial conservation of the axial current (PCAC), provided that the leptonic momentum transferred square Q{sup 2} remains sufficiently small. We give the formulas for the charged and neutral current cross sections, including also the small non-PCAC transverse current contributions and taking into account the effect of the {mu}{sup -}-mass. Our results are compared with the experimental ones and other theoretical treatments.

  16. Heavy quark production in neutrino deep-inelastic scattering

    SciTech Connect

    Johnson, J.A.; Vakili, M.; Wu, V.; Bazarko, A.O.; Conrad, J.M.; Formaggio, J.A.; Kim, J.H.; King, B.J.; Koutsoliotas, S.; McNulty, C.; Mishra, S.R.; Romosan, A.; Sculli, F.J.; Seligman, W.G.; Shaevitz, M.H.; Spentzouris, P.; Stern, E.G.; Tamminga, B.M.; Vaitaitis, A.; Bugel, L.; Lamm, M.J.; Marsh, M.; Nienaber, P.; Yu, J.; Alton, A.; Bolton, T.; Goldman, J.; Goncharov, M.; Naples, D.; Buchholz, D.; Harris, D.A.; Schellman, H.M.; Zeller, G.P.; Drucker, R.B.; Frey, R.; Mason, D.; de Barbaro, P.; Bodek, A.; Budd, H.; McFarland, K.S.; Sakumoto, W.K.; Yang, U.K.; Smith, W.H.

    1999-02-01

    Charm production by neutrino charged-current interactions produces two muon (dimuon) events which are easily identified. This signal provides an important method to measure the strange sea and the mass of the charm quark. Several experiments, including CCFR, CDHS and CHARM II, have performed analyses of such events. The results of these analyses are summarized with emphasis on CCFR and improvements made by NuTeV. {copyright} {ital 1999 American Institute of Physics.}

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

    SciTech Connect

    Schlosser, M.J.; Shurina, R.D.; Kalf, G.F. )

    1989-07-01

    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.

  18. Scale-up of the production of highly reactive biogenic magnetite nanoparticles using Geobacter sulfurreducens

    PubMed Central

    Byrne, J. M.; Muhamadali, H.; Coker, V. S.; Cooper, J.; Lloyd, J. R.

    2015-01-01

    Although there are numerous examples of large-scale commercial microbial synthesis routes for organic bioproducts, few studies have addressed the obvious potential for microbial systems to produce inorganic functional biomaterials at scale. Here we address this by focusing on the production of nanoscale biomagnetite particles by the Fe(III)-reducing bacterium Geobacter sulfurreducens, which was scaled up successfully from laboratory- to pilot plant-scale production, while maintaining the surface reactivity and magnetic properties which make this material well suited to commercial exploitation. At the largest scale tested, the bacterium was grown in a 50 l bioreactor, harvested and then inoculated into a buffer solution containing Fe(III)-oxyhydroxide and an electron donor and mediator, which promoted the formation of magnetite in under 24 h. This procedure was capable of producing up to 120 g of biomagnetite. The particle size distribution was maintained between 10 and 15 nm during scale-up of this second step from 10 ml to 10 l, with conserved magnetic properties and surface reactivity; the latter demonstrated by the reduction of Cr(VI). The process presented provides an environmentally benign route to magnetite production and serves as an alternative to harsher synthetic techniques, with the clear potential to be used to produce kilogram to tonne quantities. PMID:25972437

  19. Surface-enhanced Raman scattering of silver thin films on as-roughened substrate by reactive ion etching

    NASA Astrophysics Data System (ADS)

    Hong, Ruijin; Song, Xiao; Tao, Chunxian; Zhang, Daohua; Zhang, Dawei

    2016-03-01

    A series of silver films with various degrees of roughness were deposited on smooth and roughened substrates by magnetron sputtering. The effects of substrate roughness on the structure and optical properties of silver thin films were investigated by atomic force microscopy, X-ray diffraction (XRD), optical absorption/scattering, and Raman scattering spectra measurements, respectively. XRD spectra indicate that the substrate roughness has the effects of varying the preferential orientation of silver thin films. Both the plasma edge and interband transition peaks of silver thin films vary due to the variation of surface roughness. Both the optical and Raman scattering intensities are enhanced with the increase in surface roughness due to the surface plasmon resonance. The present fabrication of silver thin film could provide an effective way for SERS substrate.

  20. Fingerprinting the reactive toxicity pathways of 50 drinking water disinfection by-products.

    PubMed

    Stalter, Daniel; O'Malley, Elissa; von Gunten, Urs; Escher, Beate I

    2016-03-15

    A set of nine in vitro cellular bioassays indicative of different stages of the cellular toxicity pathway was applied to 50 disinfection by-products (DBPs) to obtain a better understanding of the commonalities and differences in the molecular mechanisms of reactive toxicity of DBPs. An Eschericia coli test battery revealed reactivity towards proteins/peptides for 64% of the compounds. 98% activated the NRf2-mediated oxidative stress response and 68% induced an adaptive stress response to genotoxic effects as indicated by the activation of the tumor suppressor protein p53. All DBPs reactive towards DNA in the E. coli assay and activating p53 also induced oxidative stress, confirming earlier studies that the latter could trigger DBP's carcinogenicity. The energy of the lowest unoccupied molecular orbital ELUMO as reactivity descriptor was linearly correlated with oxidative stress induction for trihalomethanes (r(2)=0.98) and haloacetamides (r(2)=0.58), indicating that potency of these DBPs is connected to electrophilicity. However, the descriptive power was poor for haloacetic acids (HAAs) and haloacetonitriles (r(2) (<) 0.06). For HAAs, we additionally accounted for speciation by including the acidity constant with ELUMO in a two-parameter multiple linear regression model. This increased r(2) to >0.80, indicating that HAAs' potency is connected to both, electrophilicity and speciation. Based on the activation of oxidative stress response and the soft electrophilic character of most tested DBPs we hypothesize that indirect genotoxicity-e.g., through oxidative stress induction and/or enzyme inhibition-is more plausible than direct DNA damage for most investigated DBPs. The results provide not only a mechanistic understanding of the cellular effects of DBPs but the effect concentrations may also serve to evaluate mixture effects of DBPs in water samples. PMID:26773486

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

    NASA Astrophysics Data System (ADS)

    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.

    2013-01-01

    We present new experimental and theoretical results for reactive scattering of dihydrogen from Cu(100). In the new experiments, the associative desorption of H2 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 H2 and on rovibrationally elastic and inelastic scattering of H2 and D2 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 H2 on Cu(100), and a highly accurate description is obtained of rovibrationally elastic and inelastic scattering of D2 from Cu(100) and of the orientational dependence of the reaction of (v = 1, j = 2 - 4) H2 on Cu(100). This suggests that a SRP density functional derived for H2 interacting with a specific low index face of a metal will yield accurate results for H2 reactively scattering from another low index face of the same metal, and that it may also yield accurate results for H2 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 H2 from Cu(100), and of the orientational dependence of reaction of (v = 0, j = 3 - 5, 8) H2 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.

  2. Single europium-doped nanoparticles measure temporal pattern of reactive oxygen species production inside cells.

    PubMed

    Casanova, Didier; Bouzigues, Cdric; Nguyn, Thanh-Lim; Ramodiharilafy, Rivo O; Bouzhir-Sima, Latifa; Gacoin, Thierry; Boilot, Jean-Pierre; Tharaux, Pierre-Louis; Alexandrou, Antigoni

    2009-09-01

    Low concentrations of reactive oxygen species, notably hydrogen peroxide (H(2)O(2)), mediate various signalling processes in the cell. Production of these signals is highly regulated and a suitable probe is needed to measure these events. Here, we show that a probe based on a single nanoparticle can quantitatively measure transient H(2)O(2) generation in living cells. The Y(0.6)Eu(0.4)VO(4) nanoparticles undergo photoreduction under laser irradiation but re-oxidize in the presence of oxidants, leading to a recovery in luminescence. Our probe can be regenerated and reliably detects intracellular H(2)O(2) with a 30-s temporal resolution and a dynamic range of 1-45 microM. The differences in the timing of intracellular H(2)O(2) production triggered by different signals were also measured using these nanoparticles. Although the probe is not selective towards H(2)O(2), in many signalling processes H(2)O(2) is, however, the dominant oxidant. In conjunction with appropriate controls, this probe is a powerful tool for unravelling pathways that involve reactive oxygen species. PMID:19734931

  3. Production and characterisation of a recombinant scFv reactive with human gastrointestinal carcinomas.

    PubMed

    Kim, D-J; Chung, J-H; Ryu, Y-S; Rhim, J-H; Kim, C-W; Suh, Y; Chung, H-K

    2002-08-12

    SC142-reactive antigen are highly glycosylated glycoproteins expressed on tissues of gastric and colon cancers but not on normal tissues. Murine SC142 antibody specific for the SC142-reactive antigen has been produced by immunisation with SNU16 stomach cancer cells. However, SC142 antibody has several potential problems such as high immunogenicity and poor tumour penetration owing to their large size. To improve tumour penetration potential in vivo, recombinant single-chain fragments have been produced using the original hybridoma cells as a source of variable heavy- and variable light-chain-encoding antibody genes. The use of the polymerase chain reaction, expression cloning technology and gene expression systems in E. coli has led to the production of SC142 single-chain fragments, which was similar in activity to the SC142 parent antibody confirmed by immunohistochemistry. Analysis by DNA sequencing, SDS-PAGE and Western blotting has demonstrated the integrity of the single-chain fragments. Competitive ELISA showed that SC142 single-chain fragments originated from parent SC142 antibody. BIAcore biosensor binding experiments showed that the SC142 single-chain fragments had an ideal dissociation rate constant as a tumour imaging reagent. These results illustrate the potential application of these novel products as an immunodiagnostic and further immunotherapeutic reagent. PMID:12177777

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

    NASA Astrophysics Data System (ADS)

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

    2009-12-01

    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.

  5. Surface reactivity, cytotoxic, and morphological transforming effects of diatomaceous Earth products in Syrian hamster embryo cells.

    PubMed

    Elias, Zo; Poirot, Odile; Fenoglio, Ivana; Ghiazza, Mara; Danire, Marie-Cleste; Terzetti, Francine; Darne, Christian; Coulais, Catherine; Matekovits, Ildiko; Fubini, Bice

    2006-06-01

    In order to evaluate the effect of thermal treatments on the surface reactivity and carcinogenic potential of diatomaceous earth (DE) products, the physicochemical features of some specimens--derived by heating the same original material--were compared with their cytotoxic and transforming potency. The samples were an untreated DE (amorphous) progressively heated in the laboratory at 900 degrees C (DE 900) and 1200 degrees C (DE 1200) and a commercial product manufactured from the same DE (Chd) from which the finer fraction (< 10-microm diameter) was separated (Chd-F). Quartz (Min-U-Sil 5) and a vitreous silica (amorphous) smoothed up with hydrofluoric acid and were used as positive and negative controls, respectively. All samples were analyzed for their degree of crystallization, for their ability to release free radicals and reactive oxygen species, and for their cytotoxic and transforming potencies in Syrian hamster embryo (SHE) cells. X-ray diffractometry showed that DE 900, like DE, was still amorphous, whereas DE 1200 as well as the commercial product (Chd) were partially crystallized into cristobalite. The ability of the dust to release hydroxyl (*OH) radicals in the presence of hydrogen peroxide, as revealed by the spin-trapping technique, was as follows: Chd-F, DE 1200 > Chd > DE 900 > DE, suggesting that on heating, the surface acquires a higher potential for free radical release. Most of the silica samples generated COO* radicals from the formate ion, following homolytic rupture of the carbon-hydrogen bond, in the presence of ascorbic acid. A concentration-dependent decrease in cell proliferation and colony-forming efficiency was observed in SHE cultures treated with Chd-F, Chd, and DE. Heating abolished DE cytotoxicity but conferred a transforming ability to thermal treated particles. DE was the only sample that did not induce morphological transformation of cells. According to their transformation capacity, the samples were classified as follows: Chd-F > Chd, DE 1200 > DE 900 > DE. Taken together, the reported results suggest that (1) the transforming potential of a biogenic amorphous silica is related to the thermal treatment that transforms the original structure in cristobalite and generates surface active sites; (2) the reactivity of samples in releasing *OH radicals correlates to their transforming ability; (3) the finer fraction of the commercial product is significantly more toxic and transforming than the coarse dust; and (4) opposite to silica dusts of mineral origin, which loose both cytotoxicity and transforming ability upon heating, heated diatomite acquires a cell-transforming potency. DE products should be thus considered a set apart of silica-based potentially toxic materials. PMID:16571621

  6. Evaluating the double parton scattering contribution to Mueller-Navelet jets production at the LHC

    NASA Astrophysics Data System (ADS)

    Duclou, B.; Szymanowski, L.; Wallon, S.

    2015-10-01

    We propose a model to study the importance of double parton scattering (DPS) in Mueller-Navelet jets production at the LHC which is consistent with the Balitsky-Fadin-Kuraev-Lipatov framework used to compute the single parton scattering contribution to this process. We study this model in kinematics corresponding to existing and possible future measurements at the LHC and estimate the importance of this DPS contribution on relevant observables for this process, namely the cross section and the azimuthal correlation of the jets.

  7. Imaging the proton via hard exclusive production in diffractive pp scattering

    SciTech Connect

    Charles Hyde; Leonid Frankfurt; Mark Strikman; Christian Weiss

    2007-05-21

    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).

  8. Reactive oxygen species production by quercetin causes the death of Leishmania amazonensis intracellular amastigotes.

    PubMed

    Fonseca-Silva, Fernanda; Inacio, Job D F; Canto-Cavalheiro, Marilene M; Almeida-Amaral, Elmo E

    2013-08-23

    The present study reports the mechanism of the antileishmanial activity of quercetin against the intracellular amastigote form of Leishmania amazonensis. Treatment with 1 reduced the infection index in L. amazonensis-infected macrophages in a dose-dependent manner, with an IC?? value of 3.4 ?M and a selectivity index of 16.8, and additionally increased ROS generation also in a dose-dependent manner. Quercetin has been described as a pro-oxidant that induces the production of reactive oxygen species, which can cause cell death. Taken together, these results suggest that ROS production plays a role in the mechanism of action of 1 in the control of intracellular amastigotes of L. amazonensis. PMID:23876028

  9. Reactive oxygen species production and antioxidant enzyme activity during epididymal sperm maturation in Corynorhinus mexicanus bats.

    PubMed

    Edith, Arenas-Ríos; Adolfo, Rosado García; Edith, Cortés-Barberena; Mina, Königsberg; Marcela, Arteaga-Silva; Ahiezer, Rodríguez-Tobón; Gisela, Fuentes-Mascorro; Angel, León-Galván Miguel

    2016-03-01

    Prolonged sperm storage in the epididymis of Corynorhinus mexicanus bats after testicular regression has been associated with epididymal sperm maturation in the caudal region, although the precise factors linked with this phenomenon are unknown. The aim of this work is to determine the role of reactive oxygen species (ROS) and changes in antioxidant enzymatic activity occurring in the spermatozoa and epididymal fluid over time, in sperm maturation and storage in the caput, corpus and cauda of the bat epididymis. Our data showed that an increment in ROS production coincided with an increase in superoxide dismutase (SOD) activity in epididymal fluid and with a decrease in glutathione peroxidase (GPX) activity in the spermatozoa in at different time points and epididymal regions. The increase in ROS production was not associated with oxidative damage measured by lipid peroxidation. The results of the current study suggest the existence of a shift in the redox balance, which might be associated with sperm maturation and storage. PMID:26952757

  10. Analytical Expressions for the Hard-Scattering Production of Massive Partons

    SciTech Connect

    Wong, Cheuk-Yin

    2016-01-01

    We obtain explicit expressions for the two-particle differential cross section $E_c E_\\kappa d\\sigma (AB \\to c\\kappa X) /d\\bb c d \\bb \\kappa$ and the two-particle angular correlation function \\break $d\\sigma(AB$$ \\to$$ c\\kappa X)/d\\Delta \\phi \\, d\\Delta y$ in the hard-scattering production of massive partons in order to exhibit the ``ridge" structure on the away side in the hard-scattering process. The single-particle production cross section $d\\sigma(AB \\to cX) /dy_c c_T dc_T $ is also obtained and compared with the ALICE experimental data for charm production in $pp$ collisions at 7 TeV at LHC.

  11. Annato extract and ?-carotene modulate the production of reactive oxygen species/nitric oxide in neutrophils from diabetic rats

    PubMed Central

    Rossoni-Jnior, Joamyr Victor; Arajo, Glaucy Rodrigues; Pdua, Bruno da Cruz; Chaves, Mriam Martins; Pedrosa, Maria Lcia; Silva, Marcelo Eustquio; Costa, Daniela Caldeira

    2012-01-01

    Annatto has been identified as carotenoids that have antioxidative effects. It is well known that one of the key elements in the development of diabetic complications is oxidative stress. The immune system is especially vulnerable to oxidative damage because many immune cells, such as neutrophils, produce reactive oxygen species and reactive nitrogen species as part of the bodys defense mechanisms to destroy invading pathogens. Reactive oxygen species/reactive nitrogen species are excessively produced by active peripheral neutrophils, and may damage essential cellular components, which in turn can cause vascular complications in diabetes. The present study was undertaken to evaluate the possible protective effects of annatto on the reactive oxygen species and nitric oxide (NO) inhibition in neutrophils from alloxan-induced diabetic rats. Adult female rats were divided into six groups based on receiving either a standard diet with or without supplementation of annatto extract or beta carotene. All animals were sacrificed 30 days after treatment and the neutrophils were isolated using two gradients of different densities. The reactive oxygen species and NO were quantified by a chemiluminescence and spectrophotometric assays, respectively. Our results show that neutrophils from diabetic animals produce significantly more reactive oxygen species and NO than their respective controls and that supplementation with beta carotene and annatto is able to modulate the production of these species. Annatto extract may have therapeutic potential for modulation of the balance reactive oxygen species/NO induced by diabetes. PMID:22573917

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

    PubMed Central

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

    2014-01-01

    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 μTRMS and static 45 μT 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

  13. Occurrence, pathways and implications of biological production of reactive oxygen species in natural waters

    NASA Astrophysics Data System (ADS)

    Zhang, T.; Hansel, C. M.; Voelker, B. M.; Lamborg, C. H.

    2014-12-01

    Reactive oxygen species (ROS), such as superoxide (O2-) and hydrogen peroxide (H2O2) play a critical role in the redox cycling of both toxic (e.g., Hg) and nutrient (e.g., Fe) metals. Despite the discovery of extracellular ROS production in various microbial cultures, including fungi, algae and bacteria, photo-dependent processes are generally considered as the predominant source of ROS in natural waters. Here we show that biological production of ROS is ubiquitous and occurs at a significant rate in freshwater and brackish water environments. Water samples were collected from three freshwater and one brackish water ponds in Cape Cod, Massachusetts, USA, periodically from 2012 to 2014. Production of O2- and H2O2 were measured in dark incubations of natural water using a chemiluminescent and a colorimetric probe, respectively. Rates of biological ROS production were obtained by comparing unfiltered with 0.2-?m filtered samples. The role of biological activity in ROS production was confirmed by the cessation of ROS production upon addition of formaldehyde. In surface water, production rates of O2- ranged from undetectable to 96.0 30.0 nmol L-1 h-1, and production rates of H2O2 varied between 9.9 1.3 nmol L-1 h-1 and 145.6 11.2 nmol L-1 h-1. The maximum production rates of both ROS were observed in mid-summer 2013, which coincides with peak biological activity. ROS production in the water from aphotic zone was greater than in the water from photic zone. Thus, non-light dependent biological processes are likely the major contributors to ROS production in this system. Moreover, O2- production appeared to be enhanced by NADH and inhibited by proteinase-K, suggesting the possible involvement of NADH oxidoreductases in this process. The potential role of different microbial communities in ROS production, and the implications of biological ROS production for mercury speciation will also be discussed.

  14. Studying re-scattering effect in heavy-ion collision through K* production

    NASA Astrophysics Data System (ADS)

    Singha, Subhash; Mohanty, Bedangadas; Lin, Zi-Wei

    2015-05-01

    We have studied the K* production within a multi-phase transport model (AMPT) for Au+Au collisions at ? {sNN} = 200 GeV to understand the hadronic re-scattering effect on the measured yields of the resonance. The hadronic re-scattering of the K* decay daughter particles (? and K) will alter their momentum distribution thereby making it difficult to reconstruct the K* signal through the invariant mass method. An increased hadronic re-scattering effect thus leads to a decrease in the reconstructed yield of K* in the heavy-ion collisions. Through this simulation study, we argue that a decrease in K*/K ratio with the increase in collision centrality necessarily reflects the hadronic re-scattering effect. Since the re-scattering occurs in the hadronic phase and K* has a lifetime of 4 fm/c, we present a toy model-based discussion on using measured K*/K to put a lower limit on the hadronic phase lifetime in high energy nuclear collisions.

  15. Quantum reactive scattering of O({sup 3}P)+H{sub 2} at collision energies up to 4.4 eV

    SciTech Connect

    Gacesa, Marko; Kharchenko, Vasili

    2014-10-28

    We report the results of quantum scattering calculations for the O({sup 3}P)+H{sub 2} 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 {sup 3}A{sup ?} and {sup 3}A{sup ?} 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.

  16. Semiclassical study of reactive scattering in a laser field - F + H2 + barred-h times omega times /1.06 microns/ system

    NASA Technical Reports Server (NTRS)

    Yuan, J.-M.; George, T. F.

    1979-01-01

    Semiclassical calculations of collinear F+H2(nu = 0) reactive and inelastic scattering in an Nd-glass laser field of various intensities are described. The decoupling approximation developed for the Miller-George theory is used for nonadiabatic transitions between the electronic-field surfaces, and special attention is paid to the choice of a proper coordinate system for applying the decoupling approximation. An increase in the total reaction probability and population ratio of the nu = 3 over nu = 2 vibrational state of HF occurs suddenly as the field intensity increases beyond 10 TW/sq cm. It is found that in a laser field the H2 molecule can be vibrationally excited while the F atom is electronically excited.

  17. Reduced dimensionality diatom--diatom reactive scattering: Application to a model H sub 2 +A sub 2 r arrow H+HA sub 2 reaction

    SciTech Connect

    Sun, Q.; Bowman, J.M. )

    1990-01-15

    We apply a recently formulated quantum theory of diatom--diatom reactions (Q. Sun and J. M. Bowman, Int. J. Quant. Chem., Quant. Chem. Symp. {bold 23}, 9 (1989)) to a model collinear H{sub 2}+A{sub 2}{r arrow}H+HA{sub 2} reaction, where A has the mass of a hydrogen atom. The theory assumes one diatom bond is nonreactive, and the reactive scattering Hamiltonian is written in terms of hyperspherical and cylindrical coordinates. The potential-energy surface used is the PK2 H+H{sub 2} surface augmented by a harmonic degree of freedom describing the nonreactive A{sub 2}. Details of the formulation and solution of the coupled-channel equations are given, along with convergence tests, and a discussion of the new state-to-state transition probabilities. In particular, the partial quenching of the well-known collinear H+H{sub 2} resonances is noted.

  18. Ultraendurance exercise increases the production of reactive oxygen species in isolated mitochondria from human skeletal muscle.

    PubMed

    Sahlin, Kent; Shabalina, Irina G; Mattsson, C Mikael; Bakkman, Linda; Fernström, Maria; Rozhdestvenskaya, Zinaida; Enqvist, Jonas K; Nedergaard, Jan; Ekblom, Björn; Tonkonogi, Michail

    2010-04-01

    Exercise-induced oxidative stress is important for the muscular adaptation to training but may also cause muscle damage. We hypothesized that prolonged exercise would increase mitochondrial production of reactive oxygen species (ROS) measured in vitro and that this correlates with oxidative damage. Eight male athletes (24-32 yr) performed ultraendurance exercise (kayaking/running/cycling) with an average work intensity of 55% V(O(2peak)) for 24 h. Muscle biopsies were taken from vastus lateralis before exercise, immediately after exercise, and after 28 h of recovery. The production of H(2)O(2) was measured fluorometrically in isolated mitochondria with the Amplex red and peroxidase system. Succinate-supported mitochondrial H(2)O(2) production was significantly increased after exercise (73% higher, P = 0.025) but restored to the initial level at recovery. Plasma level of free fatty acids (FFA) increased fourfold and exceeded 1.2 mmol/l during the last 6 h of exercise. Plasma FFA at the end of exercise was significantly correlated to mitochondrial ROS production (r = 0.74, P < 0.05). Mitochondrial content of 4-hydroxy-nonenal-adducts (a marker of oxidative damage) was increased only after recovery and was not correlated with mitochondrial ROS production. Total thiol group level and glutathione peroxidase activity were elevated after recovery. In conclusion, ultraendurance exercise increases ROS production in isolated mitochondria, but this is reversed after 28 h recovery. Mitochondrial ROS production was not correlated with oxidative damage of mitochondrial proteins, which was increased at recovery but not immediately after exercise. PMID:20110545

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

    PubMed Central

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

    2014-01-01

    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

  20. Francisella tularensis Antioxidants Harness Reactive Oxygen Species to Restrict Macrophage Signaling and Cytokine Production*

    PubMed Central

    Melillo, Amanda A.; Bakshi, Chandra Shekhar; Melendez, J. Andrs

    2010-01-01

    Francisella tularensis is the etiologic agent of the highly infectious animal and human disease tularemia. Its extreme infectivity and virulence are associated with its ability to evade immune detection, which we now link to its robust reactive oxygen species-scavenging capacity. Infection of primary human monocyte-derived macrophages with virulent F. tularensis SchuS4 prevented proinflammatory cytokine production in the presence or absence of IFN-? compared with infection with the attenuated live vaccine strain. SchuS4 infection also blocked signals required for macrophage cytokine production, including Akt phosphorylation, I?B? degradation, and NF-?B nuclear localization and activation. Concomitant with SchuS4-mediated suppression of Akt phosphorylation was an increase in the levels of the Akt antagonist PTEN. Moreover, SchuS4 prevented the H2O2-dependent oxidative inactivation of PTEN compared with a virulent live vaccine strain. Mutation of catalase (katG) sensitized F. tularensis to H2O2 and enhanced PTEN oxidation, Akt phosphorylation, NF-?B activation, and inflammatory cytokine production. Together, these findings suggest a novel role for bacterial antioxidants in restricting macrophage activation through their ability to preserve phosphatases that temper kinase signaling and proinflammatory cytokine production. PMID:20558723

  1. Prompt J/ ψ production in charged-current deep-inelastic scattering

    NASA Astrophysics Data System (ADS)

    Kniehl, Bernd A.; Zwirner, Lennart

    2004-02-01

    We calculate the cross section of J/ ψ inclusive production in lepton-nucleon deep-inelastic scattering via the weak charged current within the factorization formalism of nonrelativistic quantum chromodynamics. The hadronic system produced in association with the J/ ψ meson can be of light-quark origin or contain charm. We take into account both direct production and feed-down from directly-produced heavier charmonia. We provide the cross sections of all contributing partonic subprocesses in analytic form. We present theoretical predictions for the J/ ψ transverse-momentum and rapidity distributions, which can be measured in current neutrino-nucleon scattering experiments at CERN and Fermilab, and possibly at the future electron-proton collider THERA at DESY. We find the cross section to be at the edge of observability at DESY HERA.

  2. Interactions of U.S. Agricultural Production with Climatic Stresses and Reactive Nitrogen

    NASA Astrophysics Data System (ADS)

    Gehl, R. J.; Robertson, G. P.; Bruulsema, T. W.; Kanter, D.; Mauzerall, D. L.; Rotz, C. A.; Williams, C. O.

    2011-12-01

    Agricultural production both contributes to and responds to climatic variations across spatial and temporal continuums. The agriculture sector is responsible for over 6% of total U.S. greenhouse gas emissions, primarily as methane (CH4) and nitrous oxide (N2O) gases emitted by agricultural activities. Agriculture activities specifically account for about 69% of U.S. N2O emissions, largely as a result of production practices including fertilizer management, cropping systems, and manure management. Fertilizers, together with manure and legume fixation, are the three main inputs of N to US agricultural soils. All three sources have been increasing over the past two decades, while the rate at which they are removed in the form of harvested crops has been increasing at a slightly slower rate. The outlook for continued large areas of cultivation in the U.S., specifically for corn production and supported by biofuel production goals, is a major factor in sustaining demand for N fertilizer. However, rising fertilizer prices and environmental pressures on producers are encouraging increased adoption of emerging technologies such as precision agriculture, cultivars with higher N use efficiency, and enhanced-efficiency N sources such as controlled-release forms or forms with urease or nitrification inhibitors. Crop productivity also responds to climatic changes, as crop growth is affected by variables including heat, drought, ozone (O3), and increased ambient carbon dioxide (CO2). We summarize sources and fates of N for cropping systems and intensive animal systems and assess how climate change will affect crop response to and recovery of N and subsequent cascading effects on Nr. The complex interactions between agricultural Nr and climate present opportunities for mitigation/adaption relative to N use. N fertilizer and manure management, tillage, technology, and decision support models provide significant opportunities for climate mitigation and adaption in U.S. agriculture. Here we summarize reactive nitrogen (Nr)-climate interactions as they relate to U.S. agricultural production.

  3. Reactive oxidation products promote secondary organic aerosol formation from green leaf volatiles

    NASA Astrophysics Data System (ADS)

    Hamilton, J. F.; Lewis, A. C.; Carey, T. J.; Wenger, J. C.; Garcia, E. Borrás. I.; Muñoz, A.

    2009-06-01

    Green leaf volatiles (GLVs) are an important group of chemicals released by vegetation which have emission fluxes that can be significantly increased when plants are damaged or stressed. A series of simulation chamber experiments has been conducted at the European Photoreactor in Valencia, Spain, to investigate secondary organic aerosol (SOA) formation from the atmospheric oxidation of the major GLVs cis-3-hexenylacetate and cis-3-hexen-1-ol. Liquid chromatography-ion trap mass spectrometry was used to identify chemical species present in the SOA. Cis-3-hexen-1-ol proved to be a more efficient SOA precursor due to the high reactivity of its first generation oxidation product, 3-hydroxypropanal, which can hydrate and undergo further reactions with other aldehydes resulting in SOA dominated by higher molecular weight oligomers. The lower SOA yields produced from cis-3-hexenylacetate are attributed to the acetate functionality, which inhibits oligomer formation in the particle phase. Based on observed SOA yields and best estimates of global emissions, these compounds may be calculated to be a substantial unidentified global source of SOA, contributing 1-5 TgC yr-1, equivalent to around a third of that predicted from isoprene. Molecular characterization of the SOA, combined with organic mechanistic information, has provided evidence that the formation of organic aerosols from GLVs is closely related to the reactivity of their first generation atmospheric oxidation products, and indicates that this may be a simple parameter that could be used in assessing the aerosol formation potential for other unstudied organic compounds in the atmosphere.

  4. Reactive oxidation products promote secondary organic aerosol formation from green leaf volatiles

    NASA Astrophysics Data System (ADS)

    Hamilton, J. F.; Lewis, A. C.; Carey, T. J.; Wenger, J. C.; Garcia, E. Borrás. I.; Muñoz, A.

    2009-02-01

    Green leaf volatiles (GLVs) are an important group of chemicals released by vegetation which have emission fluxes that can be significantly increased when plants are damaged or stressed. A series of simulation chamber experiments has been conducted at the European Photoreactor in Valencia, Spain, to investigate secondary organic aerosol (SOA) formation from the atmospheric oxidation of the major GLVs cis-3-hexenylacetate and cis-3-hexen-1-ol. Liquid chromatography-ion trap mass spectrometry was used to identify chemical species present in the SOA. Cis-3-hexen-1-ol proved to be a more efficient SOA precursor due to the high reactivity of its first generation oxidation product, 3-hydroxypropanal, which can hydrate and undergo further reactions with other aldehydes resulting in SOA dominated by higher molecular weight oligomers. The lower SOA yields produced from cis-3-hexenylacetate are attributed to the acetate functionality, which inhibits oligomer formation in the particle phase. Based on observed SOA yields and best estimates of global emissions, these compounds may be calculated to be a substantial unidentified global source of SOA, contributing 1-5 TgC yr-1, equivalent to around a third of that predicted from isoprene. Molecular characterization of the SOA, combined with organic mechanistic information, has provided evidence that the formation of organic aerosols from GLVs is closely related to the reactivity of their first generation atmospheric oxidation products, and indicates that this may be a simple parameter that could be used in assessing the aerosol formation potential for other unstudied organic compounds in the atmosphere.

  5. Reactivation of Kaposis sarcoma-associated herpesvirus by natural products from Kaposis sarcoma endemic regions

    PubMed Central

    Whitby, Denise; Marshall, Vickie A.; Bagni, Rachel K.; Miley, Wendell J.; McCloud, Thomas G.; Hines-Boykin, Rebecca; Goedert, James J.; Conde, Betty A.; Nagashima, Kunio; Mikovits, Judy; Dittmer, Dirk P.; Newman, David J.

    2010-01-01

    Kaposis sarcoma (KS) and its causative agent, Kaposis sarcoma associated herpesvirus (KSHV/HHV-8), a gamma2 herpesvirus, have distinctive geographical distributions that are largely unexplained. We propose the oncoweed hypothesis to explain these differences, namely that environmental cofactors present in KS endemic regions cause frequent reactivation of KSHV in infected subjects, leading to increased viral shedding and transmission leading to increased prevalence of KSHV infection as well as high viral load levels and antibody titers. Reactivation also plays a role in the pathogenesis of KSHV-associated malignancies. To test this hypothesis, we employed an in vitro KSHV reactivation assay that measured increases in KSHV viral load in KSHV infected primary effusion lymphoma (PEL) cells and screened aqueous natural product extracts from KS endemic regions. Of 4,842 extracts from 38 countries, 184 (5%) caused KSHV reactivation. Extracts that caused reactivation came from a wide variety of plant families, and extracts from Africa, where KSHV is highly prevalent, caused the greatest level of reactivation. Time course experiments were performed using 28 extracts that caused the highest levels of reactivation. The specificity of the effects on viral replication was examined using transcriptional profiling of all viral mRNAs. The array data indicated that the natural extracts caused an ordered cascade of lytic replication similar to that seen after induction with synthetic activators. These in vitro data provide support for the oncoweed hypothesis by demonstrating basic biological plausibility. PMID:17066452

  6. Electron transport chain inhibitors induce microglia activation through enhancing mitochondrial reactive oxygen species production.

    PubMed

    Ye, Junli; Jiang, Zhongxin; Chen, Xuehong; Liu, Mengyang; Li, Jing; Liu, Na

    2016-01-15

    Reactive oxygen species (ROS) are believed to be mediators of excessive microglial activation, yet the resources and mechanism are not fully understood. Here we stimulated murine microglial BV-2 cells and primary microglial cells with different inhibitors of electron transport chain (ETC), rotenone, thenoyltrifluoroacetone (TTFA), antimycin A, and NaN3 to induce mitochondrial ROS production and we observed the role of mitochondrial ROS in microglial activation. Our results showed that ETC inhibitors resulted in significant changes in cell viability, microglial morphology, cell cycle arrest and mitochondrial ROS production in a dose-dependent manner in both primary cultural microglia and BV-2 cell lines. Moreover, ETC inhibitors, especially rotenone and antimycin A stimulated secretion of interleukin 1β (IL-1β), interleukin 6 (IL-6), interleukin 12 (IL-12) and tumor necrosis factor α (TNF-α) by microglia with marked activation of mitogen-activated proteinkinases (MAPKs) and nuclear factor κB (NF-κB), which could be blocked by specific inhibitors of MAPK and NF-κB and mitochondrial antioxidants, Mito-TEMPO. Taken together, our results demonstrated that inhibition of mitochondrial respiratory chain in microglia led to production of mitochondrial ROS and therefore may activate MAPK/NF-кB dependent inflammatory cytokines release in microglia, which indicated that mitochondrial-derived ROS were contributed to microglial activation. PMID:26511505

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

    SciTech Connect

    Kwong, S.; Small, J.

    2007-07-01

    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 of grouts to remediate ground contamination. The behaviour of fission products in these scenarios is a complex interaction of hydrogeological and geochemical processes. A suite of modelling tools have been developed to investigate the behaviour of a radioactive plume containing Cs and Sr. Firstly the effects of sorption due to cementitious groundwater is modelled using PHREEQC. This chemical model is then incorporated into PHAST for the 3-D reactive solute transport modeling. Results are presented for a generic scenario including features and processes that are likely to be relevant to a number of civil UK nuclear sites. Initial results show that modelling can be a very cost-effective means to study the complex hydrogeological and geochemical processes involved. Modelling can help predict the mobility of contaminants in a range of site end point scenarios, and in assessing the consequences of decommissioning activities. (authors)

  8. Mechanisms of photochemistry and reactive oxygen production by fullerene suspensions in water.

    PubMed

    Hotze, Ernest M; Labille, Jerome; Alvarez, Pedro; Wiesner, Mark R

    2008-06-01

    Buckminsterfullerene (C60) is a known photosensitizer that produces reactive oxygen species (ROS) in the presence of light; however, its properties in aqueous environments are still not well understood or modeled. In this study, production of both singlet oxygen and superoxide by UV photosensitization of colloidal aggregates of C60 in water was measured by two distinct methods: electron paramagnetic resonance (EPR) with a spin trapping compound, and spectrophotometric detection of the reduced form of the tetrazolium compound XTT. Both singlet oxygen and superoxide were generated by fullerol suspensions while neither was detected in the aqu/nC60 suspensions. A mechanistic framework for photosensitization that takes into account differences in C60 aggregate structure in water is proposed to explain these results. While theory developed for single molecules suggests that alterations to the C60 cage should reduce the quantum yield for the triplet state and associated ROS production, the failure to detect ROS production by aqu/nC60 is explained in part by a more dense aggregate structure compared with the hydroxylated C60. PMID:18589984

  9. Multiply scattered waves through a spatially random medium : entropy production and depolarization

    NASA Astrophysics Data System (ADS)

    Bicout, Dominique; Brosseau, Christian

    1992-11-01

    This paper deals with the depolarization and decoherence effects of an incident pure state of polarization and of arbitrary state of coherence by a linear scattering medium which changes randomly with position. Using symmetry arguments and a maximum entropy principle we deduce the general form of the Mueller matrix describing the scattering medium which is consistent with the explicit computation done in the context of the Bethe-Salpeter equation handled in the diffusion approximation. The main result expresses the output degree of polarization and degree of spatial coherence as a function of the number of scattering events. From these results, two main conclusions can be drawn. The first is that the entropy production per scattering due to the irreversible process of depolarization is an exponentially decreasing function of the number of scattering events. The second result obtained is that full depolarization of linearly polarized light by Rayleigh scatterers requires more scattering events (typically a factor-of-2) than are required for a circularly polarized lightwave. Dans cette tude, on considre les phnomnes de dpolarisation et de dcohrence d'un faisceau d'ondes planes incident, d'tat pur de polarisation et d'tat arbitraire de cohrence, par intraction avec un milieu diffusant dsordonn. Par des arguments de symtrie et un principe d'entropie maximum, nous dduisons la forme de la matrice de Mueller caractrisant le milieu diffusant qui est en accord avec le calcul explicite bas sur l'quation de Bethe-Salpeter traite dans l'approximation de la diffusion. Le rsultat principal exprime les degrs de polarisation et de cohrence spatiale en fonction du nombre de diffusions. Deux faits saillants sont noter. Le premier exprime la dcroissance exponentielle de la production d'entropie due l'irrversibilit du processus de dpolarisation, en fonction du nombre de diffusions. Le second indique que la dpolarisation complte d'un faisceau incident polaris linairement par des diffuseurs de type Rayleigh ncessite davantage de diffusions (facteur 2) que pour une polarisation circulaire.

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

    PubMed Central

    2014-01-01

    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

  11. The ozone productivity of n-propyl bromide: Part 2--An exception to the Maximum Incremental Reactivity Scale.

    PubMed

    Whitten, Gary Z; Yarwood, Greg

    2008-07-01

    In an earlier paper the ozone-forming potential of n-propyl bromide (NPB) was studied with a new methodology designed to address issues associated with a marginal smog-forming compound. However, the U.S. Environmental Protection Agency (EPA) subsequently revised its policy and now recommends using the Maximum Incremental Reactivity (MIR) scale to rank the ozone-forming potential of all volatile organic compounds (VOCs), including those of marginal ozone productivity. Nevertheless, EPA contemplated exceptions to the box-model-derived MIR scale by allowing use of photochemical grid-model simulations for case specific reactivity assessments. The California Air Resources Board (CARB) also uses the MIR scale and CARB has a Reactivity Scientific Advisory Committee that can consider exceptions to the MIR scale. In this study, grid-model simulations that were recommended by EPA are used to evaluate the incremental ozone impacts of NPB using an update to the chemical mechanism developed in an earlier paper. New methods of analysis of the grid-model output are further developed here to quantify the relative reactivities between NPB and ethane over a wide range of conditions. The new grid-model-based analyses show that NPB is significantly different and generally less in ozone-forming potential (i.e., reactivity) than predicted by the box-model-based MIR scale relative to ethane, EPA's "bright-line" test for non-VOC status. Although NPB has low reactivity compared to typical VOCs on any scale, the new grid-model analyses developed here show that NPB is far less reactive (and even has negative reactivity) compared to the reactivity predicted by the MIR scale. PMID:18672713

  12. Elastic scattering and ?-particle production in 6He + 208Pb collisions at 22 MeV

    NASA Astrophysics Data System (ADS)

    Acosta, L.; Snchez-Bentez, A. M.; Gmez, M. E.; Martel, I.; Prez-Bernal, F.; Pizarro, F.; Rodrguez-Quintero, J.; Rusek, K.; Alvarez, M. A. G.; Andrs, M. V.; Espino, J. M.; Fernndez-Garca, J. P.; Gmez-Camacho, J.; Moro, A. M.; Angulo, C.; Cabrera, J.; Casarejos, E.; Demaret, P.; Borge, M. J. G.; Escrig, D.; Tengblad, O.; Cherubini, S.; Figuera, P.; Gulino, M.; Freer, M.; Metelko, C.; Ziman, V.; Raabe, R.; Mukha, I.; Smirnov, D.; Kakuee, O. R.; Rahighi, J.

    2011-10-01

    Experimental results of the elastic scattering of 6He on 208Pb at ELAB=22 MeV, measured at the CRC facility (Louvain-la-Neuve, Belgium), are presented, including results on the 4He production channel. These data were taken with full angular coverage and high angular resolution. Both experimental cross sections are compared with continuum discretized coupled channels and distorted-wave Born approximation calculations, where direct breakup and transfer to the continuum processes are considered. The elastic data confirm the absence of the Coulomb rainbow, while the distribution of ? particles indicates that such production is mostly generated by transfer to the continuum.

  13. Reactive scattering dynamics of rotational wavepackets: a case study using the model H+H2 and F+H2 reactions with aligned and anti-aligned H2.

    PubMed

    Eyles, C J; Leibscher, M

    2013-09-14

    We propose a method to steer the outcome of reactive atom-diatom scattering, using rotational wavepackets excited by strong non-resonant laser pulses. Full close-coupled quantum mechanical scattering calculations of the D+H2 and F+H2 reactions are presented, where the H2 molecule exists as a coherent superposition of rotational states. The nuclear spin selective control over the molecular bond axis alignment afforded by the creation of rotational wavepackets is applied to reactive scattering systems, enabling a nuclear spin selective influence to be exerted over the reactive dynamics. The extension of the conventional eigenstate-to-eigenstate scattering problem to the case in which the initial state is composed of a coherent superposition of rotational states is detailed, and a selection of example calculations are discussed, along with their mechanistic implications. The feasibility of the corresponding experiments is considered, and a suitable simple two pulse laser scheme is shown to strongly differentiate the reactivities of o-H2 and p-H2. PMID:24050352

  14. Why Particle Dispersions Matter: Product Discovery and Problem Solving in the Hydrocarbon Industry Through Neutron Scattering

    NASA Astrophysics Data System (ADS)

    King, Hubert

    2010-03-01

    A surprisingly wide range of matter consists of dispersions of one material in another. In the hydrocarbon industry we often work with mixtures of solid, liquid, and gas as a consequence of the production of hydrocarbons. For example, in deep sea oil production solid phases of wax or gas hydrates can form in pipelines due to low temperatures and high pressures. Dispersions also arise in the products we design; examples include polymers, fuel additives, and lubricants. Hence, understanding such dispersions is a key technology. Size of the dispersed phase (supermolecular) and sensitivity of the structure to the presence of a fluid phase (high-vacuum imaging methods are difficult), makes the small-angle scattering technique, using light, x-rays, and neutrons, a preferred method of structure determination. We focus in this talk on neutron scattering, and this method has several strengths: 1) contrast matching to highlight features is easily achieved through use of various isotopes, for example ^1H vs ^2H, 2) an unprecedented range of length scales is accessible (several ?m to nm) through the combined use of SANS and USANS, and 3) the concentration of scattering entities is precisely determined because scattering is routinely measured on an absolute basis. When one considers small-angle scattering from a dispersion, simple models such as Debye scattering, where the magnitude of the momentum transfer (q=2? Sin(?)/?) is comparable to the size of the dispersed phases (R*q1), is often used to estimate the size of the dispersed phase. However, this simple approach fails in many real-world cases where we must deal with, for example, high concentrations of solids or highly-anisotropic dispersed phases. In this talk we will illustrate how we have utilized combined SANS / USANS data along with contrast matching techniques to understand the structure-property relations governing behavior in several areas of interest, including self-assembly of polymers in fuel additives, polymer-modified gas-hydrate slurries, and organoclay dispersion/exfolation as thickening agents.

  15. First measurement of Z/?* production in compton scattering of quasi-real photons

    NASA Astrophysics Data System (ADS)

    OPAL Collaboration; Abbiendi, G.; Ackerstaff, K.; Alexander, G.; Allison, J.; Altekamp, N.; Anderson, K. J.; Anderson, S.; Arcelli, S.; Asai, S.; Ashby, S. F.; Axen, D.; Azuelos, G.; Ball, A. H.; Barberio, E.; Barlow, R. J.; Bartoldus, R.; Batley, J. R.; Baumann, S.; Bechtluft, J.; Behnke, T.; Bell, K. W.; Bella, G.; Bellerive, A.; Bentvelsen, S.; Bethke, S.; Betts, S.; Biebel, O.; Biguzzi, A.; Bird, S. D.; Blobel, V.; Bloodworth, I. J.; Bobinski, M.; Bock, P.; Bhme, J.; Bonacorsi, D.; Boutemeur, M.; Braibant, S.; Bright-Thomas, P.; Brigliadori, L.; Brown, R. M.; Burckhart, H. J.; Burgard, C.; Brgin, R.; Capiluppi, P.; Carnegie, R. K.; Carter, A. A.; Carter, J. R.; Chang, C. Y.; Charlton, D. G.; Chrisman, D.; Ciocca, C.; Clarke, P. E. L.; Clay, E.; Cohen, I.; Conboy, J. E.; Cooke, O. C.; Couyoumtzelis, C.; Coxe, R. L.; Cuffiani, M.; Dado, S.; Dallavalle, G. M.; Davis, R.; de Jong, S.; del Pozo, L. A.; de Roeck, A.; Desch, K.; Dienes, B.; Dixit, M. S.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I. P.; Eatough, D.; Estabrooks, P. G.; Etzion, E.; Evans, H. G.; Fabbri, F.; Fanti, M.; Faust, A. A.; Fiedler, F.; Fierro, M.; Fleck, I.; Folman, R.; Frtjes, A.; Futyan, D. I.; Gagnon, P.; Gary, J. W.; Gascon, J.; Gascon-Shotkin, S. M.; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Gibson, V.; Gibson, W. R.; Gingrich, D. M.; Glenzinski, D.; Goldberg, J.; Gorn, W.; Grandi, C.; Gross, E.; Grunhaus, J.; Gruw, M.; Hanson, G. G.; Hansroul, M.; Hapke, M.; Harder, K.; Hargrove, C. K.; Hartmann, C.; Hauschild, M.; Hawkes, C. M.; Hawkings, R.; Hemingway, R. J.; Herndon, M.; Herten, G.; Heuer, R. D.; Hildreth, M. D.; Hill, J. C.; Hillier, S. J.; Hobson, P. R.; Hocker, A.; Homer, R. J.; Honma, A. K.; Horvth, D.; Hossain, K. R.; Howard, R.; Hntemeyer, P.; Igo-Kemenes, P.; Imrie, D. C.; Ishii, K.; Jacob, F. R.; Jawahery, A.; Jeremie, H.; Jimack, M.; Jones, C. R.; Jovanovic, P.; Junk, T. R.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Kayal, P. I.; Keeler, R. K.; Kellogg, R. G.; Kennedy, B. W.; Klier, A.; Kluth, S.; Kobayashi, T.; Kobel, M.; Koetke, D. S.; Kokott, T. P.; Kolrep, M.; Komamiya, S.; Kowalewski, R. V.; Kress, T.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kyberd, P.; Lafferty, G. D.; Lanske, D.; Lauber, J.; Lautenschlager, S. R.; Lawson, I.; Layter, J. G.; Lazic, D.; Lee, A. M.; Lellouch, D.; Letts, J.; Levinson, L.; Liebisch, R.; List, B.; Littlewood, C.; Lloyd, A. W.; Lloyd, S. L.; Loebinger, F. K.; Long, G. D.; Losty, M. J.; Ludwig, J.; Liu, D.; Macchiolo, A.; MacPherson, A.; Mader, W.; Mannelli, M.; Marcellini, S.; Markopoulos, C.; Martin, A. J.; Martin, J. P.; Martinez, G.; Mashimo, T.; Mttig, P.; McDonald, W. J.; McKenna, J.; McKigney, E. A.; McMahon, T. J.; McPherson, R. A.; Meijers, F.; Menke, S.; Merritt, F. S.; Mes, H.; Meyer, J.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D. J.; Mir, R.; Mohr, W.; Montanari, A.; Mori, T.; Nagai, K.; Nakamura, I.; Neal, H. A.; Nellen, B.; Nisius, R.; O'Neale, S. W.; Oakham, F. G.; Odorici, F.; Ogren, H. O.; Oreglia, M. J.; Orito, S.; Plinks, J.; Psztor, G.; Pater, J. R.; Patrick, G. N.; Patt, J.; Perez-Ochoa, R.; Petzold, S.; Pfeifenschneider, P.; Pilcher, J. E.; Pinfold, J.; Plane, D. E.; Poffenberger, P.; Polok, J.; Przybycie? , M.; Rembser, C.; Rick, H.; Robertson, S.; Robins, S. A.; Rodning, N.; Roney, J. M.; Roscoe, K.; Rossi, A. M.; Rozen, Y.; Runge, K.; Runolfsson, O.; Rust, D. R.; Sachs, K.; Saeki, T.; Sahr, O.; Sang, W. M.; Sarkisyan, E. K. G.; Sbarra, C.; Schaile, A. D.; Schaile, O.; Scharf, F.; Scharff-Hansen, P.; Schieck, J.; Schmitt, B.; Schmitt, S.; Schning, A.; Schrder, M.; Schumacher, M.; Schwick, C.; Scott, W. G.; Seiler, T.; Seuster, R.; Shears, T. G.; Shen, B. C.; Shepherd-Themistocleous, C. H.; Sherwood, P.; Siroli, G. P.; Sittler, A.; Skuja, A.; Smith, A. M.; Snow, G. A.; Sobie, R.; Sldner-Rembold, S.; Sproston, M.; Stahl, A.; Stephens, K.; Steuerer, J.; Stoll, K.; Strom, D.; Strhmer, R.; Surrow, B.; Talbot, S. D.; Tanaka, S.; Taras, P.; Tarem, S.; Teuscher, R.; Thiergen, M.; Thomson, M. A.; von Trne, E.; Torrence, E.; Towers, S.; Trigger, I.; Trcsnyi, Z.; Tsur, E.; Turcot, A. S.; Turner-Watson, M. F.; van Kooten, R.; Vannerem, P.; Verzocchi, M.; Voss, H.; Wckerle, F.; Wagner, A.; Ward, C. P.; Ward, D. R.; Watkins, P. M.; Watson, A. T.; Watson, N. K.; Wells, P. S.; Wermes, N.; White, J. S.; Wilson, G. W.; Wilson, J. A.; Wyatt, T. R.; Yamashita, S.; Yekutieli, G.; Zacek, V.; Zer-Zion, D.

    1998-10-01

    We report the first observation of Z/?* production in Compton scattering of quasi-real photons. This is a subprocess of the reaction e+e--->e+e- Z/?*, where one of the final state electrons is undetected. Approximately 55 pb-1 of data collected in the year 1997 at an e+e- centre-of-mass energy of 183 GeV with the OPAL detector at LEP have been analysed. The Z/?* from Compton scattering has been detected in the hadronic decay channel. Within well defined kinematic bounds, we measure the product of cross-section and Z/?* branching ratio to hadrons to be (0.9+/-0.3+/-0.1) pb for events with a hadronic mass larger than 60 GeV, dominated by (e)eZ production. In the hadronic mass region between 5 GeV and 60 GeV, dominated by (e)e?* production, this product is found to be (4.1+/-1.6+/-0.6) pb. Our results agree with the predictions of two Monte Carlo event generators, grc4f and PYTHIA.

  16. Reactive oxygen species and IRF1 stimulate IFN? production by proximal tubules during ischemic AKI

    PubMed Central

    Winterberg, Pamela D.; Wang, Yanxia; Lin, Keng-Mean; Hartono, John R.; Nagami, Glenn T.; Zhou, Xin J.; Shelton, John M.; Richardson, James A.

    2013-01-01

    We previously reported that expression of the transcription factor interferon regulatory factor 1 (IRF1) is an early, critical maladaptive signal expressed by renal tubules during murine ischemic acute kidney injury (AKI). We now show that IRF1 mediates signals from reactive oxygen species (ROS) generated during ischemic AKI and that these signals ultimately result in production of ?-subtypes of type I interferons (IFN?s). We found that genetic knockout of the common type I IFN receptor (IFNARI?/?) improved kidney function and histology during AKI. There are major differences in the spatial-temporal production of the two major IFN subtypes, IFN? and IFN?s: IFN? expression peaks at 4 h, earlier than IFN?s, and continues at the same level at 24 h; expression of IFN?s also increases at 4 h but continues to increase through 24 h. The magnitude of the increase in IFN?s relative to baseline is much greater than that of IFN?. We show by immunohistology and study of isolated cells that IFN? is produced by renal leukocytes and IFN?s are produced by renal tubules. IRF1, IFN?s, and IFNARI were found on the same renal tubules during ischemic AKI. Furthermore, we found that ROS induced IFN? expression by renal tubules in vitro. This expression was inhibited by small interfering RNA knockdown of IRF1. Overexpression of IRF1 resulted in the production of IFN?s. Furthermore, we found that IFN? stimulated production of maladaptive proinflammatory CXCL2 by renal tubular cells. Altogether our data support the following autocrine pathway in renal tubular cells: ROS > IRF1 > IFN? > IFNARI > CXCL2. PMID:23657854

  17. Suppression of the reactive oxygen intermediates production of human macrophages by colorectal adenocarcinoma cell lines

    PubMed Central

    Siegert, A; Denkert, C; Leclere, A; Hauptmann, S

    1999-01-01

    Although some in vitro studies indicate that macrophages exert cytotoxic responses against tumour cells by production of reactive oxygen intermediates (ROI), no obvious impairment of tumour cell growth is visible in various human malignant tumours, which contain a large number of tumour‐associated macrophages (TAM). We made use of an in vivo‐like co‐culture model of multicellular tumour spheroids of three colon carcinoma cell lines (HRT‐18, HT‐29, CX‐2) and three functionally different phenotypes of human macrophages (27E10, RM3/1, 25F9) to investigate if tumour cells deactivate macrophage cytotoxicity. The production of ROI was measured by a lucigenin‐amplified chemiluminescence assay in a 96‐well‐microplate luminometer. Different capabilities to produce ROI by different macrophage phenotypes were observed. However, independent of the macrophage phenotype and the tumour cell type a significant inhibition of ROI formation was found in co‐cultures after 1 hr, 1 and 2 days. Macrophages were also suppressed by tumour cell supernatants, which contained anti‐inflammatory cytokines transforming growth factor‐β1 (TGF‐β1) and negligible levels of interleukin‐4 (IL‐4) and IL‐10 as shown by enzyme‐linked immunosorbent assay (ELISA). Although recombinant human cytokines TGF‐β1, IL‐10 and IL‐4 inhibited the production of ROI in freshly isolated monocytes, these cytokines had no effect on differentiated macrophage phenotypes, indicating that these cytokines are not involved in mediating tumour‐induced suppression of ROI production by human macrophages. PMID:10594687

  18. Production of ??+2 jets from double parton scattering in proton-proton collisions at the LHC

    NASA Astrophysics Data System (ADS)

    Tao, Jun-Quan; Zhang, Si-Jing; Shen, Yu-Qiao; Fan, Jia-Wei; Chen, Guo-Ming; Chen, He-Sheng

    2015-12-01

    Cross sections for the production of pairs of photons plus two additional jets produced from double parton scattering in high-energy proton-proton collisions at the LHC are calculated for the first time. The estimates are based on the theoretical perturbative QCD predictions for the productions of ?? at next-to-next-to-leading-order, jet+jet and ?+jet at next-to-leading-order, for their corresponding single-scattering cross sections. The cross sections and expected event rates for ??+2 jets from double parton scattering, after typical acceptance and selections, are given for proton-proton collisions with the collision energy \\sqrt{s}=13 TeV and integrated luminosity of 100 fb?1 planned for the following years, and also \\sqrt{s}=14 TeV with 3000 fb?1 of integrated luminosity as the LHC design. Supported by National Natural Science Foundation of China (11061140514, 11505208), China Ministry of Science and Technology (2013CB838700) and CAS Center for Excellence in Particle Physics (CCEPP)

  19. Insulin Regulates Glucose Consumption and Lactate Production through Reactive Oxygen Species and Pyruvate Kinase M2

    PubMed Central

    Li, Qi; Liu, Xue; Yin, Yu; Zheng, Ji-Tai; Jiang, Cheng-Fei; Wang, Jing; Shen, Hua; Li, Chong-Yong; Wang, Min; Liu, Ling-Zhi; Jiang, Bing-Hua

    2014-01-01

    Although insulin is known to regulate glucose metabolism and closely associate with liver cancer, the molecular mechanisms still remain to be elucidated. In this study, we attempt to understand the mechanism of insulin in promotion of liver cancer metabolism. We found that insulin increased pyruvate kinase M2 (PKM2) expression through reactive oxygen species (ROS) for regulating glucose consumption and lactate production, key process of glycolysis in hepatocellular carcinoma HepG2 and Bel7402 cells. Interestingly, insulin-induced ROS was found responsible for the suppression of miR-145 and miR-128, and forced expression of either miR-145 or miR-128 was sufficient to abolish insulin-induced PKM2 expression. Furthermore, the knockdown of PKM2 expression also inhibited cancer cell growth and insulin-induced glucose consumption and lactate production, suggesting that PKM2 is a functional downstream effecter of insulin. Taken together, this study would provide a new insight into the mechanism of insulin-induced glycolysis. PMID:24895527

  20. [FEATURES OF CHANGES IN THE IMMUNE REACTIVITY IN EMPLOYEES IN MODERN PRODUCTION OF SULPHATE CELLULOSE].

    PubMed

    Meshchakova, N M; Bodienkova, G M

    2015-01-01

    There are reported changes in the indices of the immunoreactivity of the body in employees in modern productions of sulphate cellulose in dependence on the specificity of exposing factors of the production environment. At that the main adverse factor affecting the state of the immune reactivity of workers was found to be is air pollution of the working area with methyl-sulfur compounds in the pulping process, with chlorine and chlorine dioxide--in the process of bleaching, lime and limestone dust--in the process of caustic regeneration. There were shown differences in the character and severity of the immune response to the impact of different chemical compounds. The exertion of protective immune mechanisms is most pronounced in workers employed in the process of boiling and bleaching, in whom there were revealed significant changes in humoral compartment of immunity (pronounced inhibition of the IgA synthesis, which plays an important role in the state of broncho-pulmonary immunity). At the same time, the inhibition of the functional activity of phagocytic neutrophils was the most significant in workers who was experienced to the exposure to lime and limestone dust, testifying about the depression of nonspecific mechanisms of anti-infectious protection. The revealed changes in the immune system are the basis for the formation in workers certain health disorders, mainly with broncho-pulmonary pathology. PMID:26625622

  1. Long-lived Indy induces reduced mitochondrial reactive oxygen species production and oxidative damage.

    PubMed

    Neretti, Nicola; Wang, Pei-Yu; Brodsky, Alexander S; Nyguyen, Hieu H; White, Kevin P; Rogina, Blanka; Helfand, Stephen L

    2009-02-17

    Decreased Indy activity extends lifespan in D. melanogaster without significant reduction in fecundity, metabolic rate, or locomotion. To understand the underlying mechanisms leading to lifespan extension in this mutant strain, we compared the genome-wide gene expression changes in the head and thorax of adult Indy mutant with control flies over the course of their lifespan. A signature enrichment analysis of metabolic and signaling pathways revealed that expression levels of genes in the oxidative phosphorylation pathway are significantly lower in Indy starting at day 20. We confirmed experimentally that complexes I and III of the electron transport chain have lower enzyme activity in Indy long-lived flies by Day 20 and predicted that reactive oxygen species (ROS) production in mitochondria could be reduced. Consistently, we found that both ROS production and protein damage are reduced in Indy with respect to control. However, we did not detect significant differences in total ATP, a phenotype that could be explained by our finding of a higher mitochondrial density in Indy mutants. Thus, one potential mechanism by which Indy mutants extend life span could be through an alteration in mitochondrial physiology leading to an increased efficiency in the ATP/ROS ratio. PMID:19164521

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

    PubMed

    Cho, Kangwoo; Hoffmann, Michael R

    2014-10-01

    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

  3. D^* production in deep-inelastic scattering at low Q^2

    SciTech Connect

    Jung, Andreas W.; /Fermilab

    2011-07-01

    Inclusive production of D* mesons in deep-inelastic scattering at HERA is studied in the range 5 < Q{sup 2} < 100 GeV{sup 2} of the photon virtuality and 0.02 < y < 0.70 of the inelasticity of the scattering process. The visible range for the D* meson is p{sub 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{sup -1}. Single and double differential cross sections are measured. The results are compared to QCD predictions.

  4. Single-inclusive production of hadrons and jets in lepton-nucleon scattering at NLO

    NASA Astrophysics Data System (ADS)

    Hinderer, Patriz; Schlegel, Marc; Vogelsang, Werner

    2015-07-01

    We present next-to-leading order (NLO) perturbative-QCD calculations of the cross sections for ?N ?h X and ?N ?jet X . The main feature of these processes is that the scattered lepton is not observed, so that the hard scale that makes them perturbative is set by the transverse momentum of the hadron or jet. Kinematically, the two processes thus become direct analogs of single-inclusive production in hadronic collisions which, as has been pointed out in the literature, makes them promising tools for exploring transverse spin phenomena in QCD when the incident nucleon is transversely polarized. We find that the NLO corrections are sizable for the spin-averaged cross section. We also investigate in how far the scattering is dominated by the exchange of almost real (Weizscker-Williams) photons. We present numerical estimates of the cross sections for present-day fixed target experiments and for a possible future electron-ion collider.

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

    PubMed Central

    Camara, Amadou K. S.

    2009-01-01

    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

  6. Increased effectiveness of carbon ions in the production of reactive oxygen species in normal human fibroblasts

    PubMed Central

    Dettmering, Till; Zahnreich, Sebastian; Colindres-Rojas, Miriam; Durante, Marco; Taucher-Scholz, Gisela; Fournier, Claudia

    2015-01-01

    The production of reactive oxygen species (ROS), especially superoxide anions (O2), is enhanced in many normal and tumor cell types in response to ionizing radiation. The influence of ionizing radiation on the regulation of ROS production is considered as an important factor in the long-term effects of irradiation (such as genomic instability) that might contribute to the development of secondary cancers. In view of the increasing application of carbon ions in radiation therapy, we aimed to study the potential impact of ionizing density on the intracellular production of ROS, comparing photons (X-rays) with carbon ions. For this purpose, we used normal human cells as a model for irradiated tissue surrounding a tumor. By quantifying the oxidization of Dihydroethidium (DHE), a fluorescent probe sensitive to superoxide anions, we assessed the intracellular ROS status after radiation exposure in normal human fibroblasts, which do not show radiation-induced chromosomal instability. After 35 days post exposure to X-rays and carbon ions, the level of ROS increased to a maximum that was dose dependent. The maximum ROS level reached after irradiation was specific for the fibroblast type. However, carbon ions induced this maximum level at a lower dose compared with X-rays. Within ?1 week, ROS decreased to control levels. The time-course of decreasing ROS coincides with an increase in cell number and decreasing p21 protein levels, indicating a release from radiation-induced growth arrest. Interestingly, radiation did not act as a trigger for chronically enhanced levels of ROS months after radiation exposure. PMID:25304329

  7. Deeply Virtual Compton Scattering and Meson Production at Jlab/CLAS

    SciTech Connect

    Hyon-Suk Jo

    2012-04-01

    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.

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

    SciTech Connect

    Guendelman, Eduardo I.; Shilon, Idan; Cantatore, Giovanni; Zioutas, Konstantin E-mail: silon@bgu.ac.il E-mail: Konstantin.Zioutas@cern.ch

    2010-06-01

    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 δ-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 δ-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.

  9. Reactive Oxygen Species Production and Brugia pahangi Survivorship in Aedes polynesiensis with Artificial Wolbachia Infection Types

    PubMed Central

    Andrews, Elizabeth S.; Crain, Philip R.; Fu, Yuqing; Howe, Daniel K.; Dobson, Stephen L.

    2012-01-01

    Heterologous transinfection with the endosymbiotic bacterium Wolbachia has been shown previously to induce pathogen interference phenotypes in mosquito hosts. Here we examine an artificially infected strain of Aedes polynesiensis, the primary vector of Wuchereria bancrofti, which is the causative agent of Lymphatic filariasis (LF) throughout much of the South Pacific. Embryonic microinjection was used to transfer the wAlbB infection from Aedes albopictus into an aposymbiotic strain of Ae. polynesiensis. The resulting strain (designated “MTB”) experiences a stable artificial infection with high maternal inheritance. Reciprocal crosses of MTB with naturally infected wild-type Ae. polynesiensis demonstrate strong bidirectional incompatibility. Levels of reactive oxygen species (ROS) in the MTB strain differ significantly relative to that of the wild-type, indicating an impaired ability to regulate oxidative stress. Following a challenge with Brugia pahangi, the number of filarial worms achieving the infective stage is significantly reduced in MTB as compared to the naturally infected and aposymbiotic strains. Survivorship of MTB differed significantly from that of the wild-type, with an interactive effect between survivorship and blood feeding. The results demonstrate a direct correlation between decreased ROS levels and decreased survival of adult female Aedes polynesiensis. The results are discussed in relation to the interaction of Wolbachia with ROS production and antioxidant expression, iron homeostasis and the insect immune system. We discuss the potential applied use of the MTB strain for impacting Ae. polynesiensis populations and strategies for reducing LF incidence in the South Pacific. PMID:23236284

  10. Silver nanoparticles affect glucose metabolism in hepatoma cells through production of reactive oxygen species.

    PubMed

    Lee, Mi Jin; Lee, Seung Jun; Yun, Su Jin; Jang, Ji-Young; Kang, Hangoo; Kim, Kyongmin; Choi, In-Hong; Park, Sun

    2016-01-01

    The silver nanoparticle (AgNP) is a candidate for anticancer therapy because of its effects on cell survival and signaling. Although numerous reports are available regarding their effect on cell death, the effect of AgNPs on metabolism is not well understood. In this study, we investigated the effect of AgNPs on glucose metabolism in hepatoma cell lines. Lactate release from both HepG2 and Huh7 cells was reduced with 5 nm AgNPs as early as 1 hour after treatment, when cell death did not occur. Treatment with 5 nm AgNPs decreased glucose consumption in HepG2 cells but not in Huh7 cells. Treatment with 5 nm AgNPs reduced nuclear factor erythroid 2-like 2 expression in both cell types without affecting its activation at the early time points after AgNPs' treatment. Increased reactive oxygen species (ROS) production was detected 1 hour after 5 nm AgNPs' treatment, and lactate release was restored in the presence of an ROS scavenger. Our results suggest that 5 nm AgNPs affect glucose metabolism by producing ROS. PMID:26730190

  11. The alternative oxidase lowers mitochondrial reactive oxygen production in plant cells

    PubMed Central

    Maxwell, Denis P.; Wang, Yong; McIntosh, Lee

    1999-01-01

    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 respiratory electron transport. Using the ROS-sensitive probe 2?,7?-dichlorofluorescein diacetate, we found that antisense suppression of AOX resulted in cells with a significantly higher level of ROS compared with wild-type cells, whereas the overexpression of AOX resulted in cells with lower ROS abundance. Laser-scanning confocal microscopy showed that the difference in ROS abundance among wild-type and AOX transgenic cells was caused by changes in mitochondrial-specific ROS formation. Mitochondrial ROS production was exacerbated by the use of antimycin A, which inhibited normal cytochrome electron transport. In addition, cells overexpressing AOX were found to have consistently lower expression of genes encoding ROS-scavenging enzymes, including the superoxide dismutase genes SodA and SodB, as well as glutathione peroxidase. Also, the abundance of mRNAs encoding salicylic acid-binding catalase and a pathogenesis-related protein were significantly higher in cells deficient in AOX. These results are evidence that AOX plays a role in lowering mitochondrial ROS formation in plant cells. PMID:10393984

  12. Silver nanoparticles affect glucose metabolism in hepatoma cells through production of reactive oxygen species

    PubMed Central

    Lee, Mi Jin; Lee, Seung Jun; Yun, Su Jin; Jang, Ji-Young; Kang, Hangoo; Kim, Kyongmin; Choi, In-Hong; Park, Sun

    2016-01-01

    The silver nanoparticle (AgNP) is a candidate for anticancer therapy because of its effects on cell survival and signaling. Although numerous reports are available regarding their effect on cell death, the effect of AgNPs on metabolism is not well understood. In this study, we investigated the effect of AgNPs on glucose metabolism in hepatoma cell lines. Lactate release from both HepG2 and Huh7 cells was reduced with 5 nm AgNPs as early as 1 hour after treatment, when cell death did not occur. Treatment with 5 nm AgNPs decreased glucose consumption in HepG2 cells but not in Huh7 cells. Treatment with 5 nm AgNPs reduced nuclear factor erythroid 2-like 2 expression in both cell types without affecting its activation at the early time points after AgNPs’ treatment. Increased reactive oxygen species (ROS) production was detected 1 hour after 5 nm AgNPs’ treatment, and lactate release was restored in the presence of an ROS scavenger. Our results suggest that 5 nm AgNPs affect glucose metabolism by producing ROS. PMID:26730190

  13. Reactive oxygen species production and Brugia pahangi survivorship in Aedes polynesiensis with artificial Wolbachia infection types.

    PubMed

    Andrews, Elizabeth S; Crain, Philip R; Fu, Yuqing; Howe, Daniel K; Dobson, Stephen L

    2012-01-01

    Heterologous transinfection with the endosymbiotic bacterium Wolbachia has been shown previously to induce pathogen interference phenotypes in mosquito hosts. Here we examine an artificially infected strain of Aedes polynesiensis, the primary vector of Wuchereria bancrofti, which is the causative agent of Lymphatic filariasis (LF) throughout much of the South Pacific. Embryonic microinjection was used to transfer the wAlbB infection from Aedes albopictus into an aposymbiotic strain of Ae. polynesiensis. The resulting strain (designated "MTB") experiences a stable artificial infection with high maternal inheritance. Reciprocal crosses of MTB with naturally infected wild-type Ae. polynesiensis demonstrate strong bidirectional incompatibility. Levels of reactive oxygen species (ROS) in the MTB strain differ significantly relative to that of the wild-type, indicating an impaired ability to regulate oxidative stress. Following a challenge with Brugia pahangi, the number of filarial worms achieving the infective stage is significantly reduced in MTB as compared to the naturally infected and aposymbiotic strains. Survivorship of MTB differed significantly from that of the wild-type, with an interactive effect between survivorship and blood feeding. The results demonstrate a direct correlation between decreased ROS levels and decreased survival of adult female Aedes polynesiensis. The results are discussed in relation to the interaction of Wolbachia with ROS production and antioxidant expression, iron homeostasis and the insect immune system. We discuss the potential applied use of the MTB strain for impacting Ae. polynesiensis populations and strategies for reducing LF incidence in the South Pacific. PMID:23236284

  14. Ultraviolet irradiation induces autofluorescence enhancement via production of reactive oxygen species and photodecomposition in erythrocytes

    SciTech Connect

    Wu, Xian; Pan, Leiting; Wang, Zhenhua; Liu, Xiaoli; Zhao, Dan; Zhang, Xinzheng; Rupp, Romano A.; Xu, Jingjun

    2010-06-11

    Ultraviolet (UV) light has a significant influence on human health. In this study, human erythrocytes were exposed to UV light to investigate the effects of UV irradiation (UVI) on autofluorescence. Our results showed that high-dose continuous UVI enhanced erythrocyte autofluorescence, whereas low-dose pulsed UVI alone did not have this effect. Further, we found that H{sub 2}O{sub 2}, one type of reactive oxygen species (ROS), accelerated autofluorescence enhancement under both continuous and pulsed UVI. In contrast, continuous and pulsed visible light did not result in erythrocyte autofluorescence enhancement in the presence or absence of H{sub 2}O{sub 2}. Moreover, NAD(P)H had little effect on UVI-induced autofluorescence enhancement. From these studies, we conclude that UVI-induced erythrocyte autofluorescence enhancement via both UVI-dependent ROS production and photodecomposition. Finally, we present a theoretical study of this autofluorescence enhancement using a rate equation model. Notably, the results of this theoretical simulation agree well with the experimental data further supporting our conclusion that UVI plays two roles in the autofluorescence enhancement process.

  15. Oxidative Folding: Cellular Strategies for Dealing with the Resultant Equimolar Production of Reactive Oxygen Species

    PubMed Central

    Shimizu, Yuichiro

    2009-01-01

    Abstract All eukaryotic cells possess an endoplasmic reticulum (ER), which is the site for synthesizing proteins that populate the cell surface or extracellular space. The environment of the ER is oxidizing, which supports the formation of intra- and interchain disulfide bonds that serve to stabilize the folding and assembly of nascent proteins. Recent experimental data reveal that the formation of disulfide bonds does not occur spontaneously but results from the enzymatic transfer of disulfide bonds through a number of intermediate proteins, with molecular oxygen serving as the terminal electron acceptor. Thus, each disulfide bond that forms during oxidative folding should produce a single reactive oxygen species (ROS). Dedicated secretory tissues like the pancreas and plasma cells have been estimated to form up to 3–6 million disulfide bonds per minute, which would be expected to result in the production of the same number of molecules of ROS. Although the methods used to deal with this amount of oxidative stress are not well understood, recent research suggests that different types of cells use distinct strategies and that the unfolded protein response (UPR) is a critical component of the defense. Antioxid. Redox Signal. 11, 2317–2331. PMID:19243234

  16. Heavy Quarkonium Production in Single Transverse Polarized HighEnergy Scattering

    SciTech Connect

    Yuan, Feng

    2008-01-17

    We formulate the single transverse spin asymmetry in heavyquarkoniumproduction in lepton-nucleon and nucleon-nucleon collisionsinthe non-relativistic limit. We findthat the asymmetry is very sensitiveto the production mechanism. The finalstate interactions with the heavyquark and antiquark cancel out among themselves whenthe pair are producedin a color-single configuration, or cancel out with the initialstateinteraction in pp scattering when they are in color-octet. As aconsequence, the asymmetry is nonzero in ep collisions only in thecolor-octet model, whereas in pp collisions only in the color-singletmodel.

  17. A phenomenological study of photon production in low energy neutrino nucleon scattering

    SciTech Connect

    Jenkins, James P; Goldman, Terry J

    2009-01-01

    Low energy photon production is an important background to many current and future precision neutrino experiments. We present a phenomenological study of t-channel radiative corrections to neutral current neutrino nucleus scattering. After introducing the relevant processes and phenomenological coupling constants, we will explore the derived energy and angular distributions as well as total cross-section predictions along with their estimated uncertainties. This is supplemented throughout with comments on possible experimental signatures and implications. We conclude with a general discussion of the analysis in the context of complimentary methodologies. This is based on a talk presented at the DPF 2009 meeting in Detroit MI.

  18. QCD CORRECTIONS TO DILEPTON PRODUCTION NEAR PARTONIC THRESHOLD IN PP SCATTERING.

    SciTech Connect

    SHIMIZU, H.; STERMAN, G.; VOGELSANG, W.; YOKOYA, H.

    2005-10-02

    We present a recent study of the QCD corrections to dilepton production near partonic threshold in transversely polarized {bar p}p scattering, We analyze the role of the higher-order perturbative QCD corrections in terms of the available fixed-order contributions as well as of all-order soft-gluon resummations for the kinematical regime of proposed experiments at GSI-FAIR. We find that perturbative corrections are large for both unpolarized and polarized cross sections, but that the spin asymmetries are stable. The role of the far infrared region of the momentum integral in the resummed exponent and the effect of the NNLL resummation are briefly discussed.

  19. Three-dimensional Monte Carlo simulation of gamma-ray scattering and production in the atmosphere

    NASA Technical Reports Server (NTRS)

    Morris, Daniel J.

    1989-01-01

    Results are reported from Monte Carlo numerical simulations of atmospheric gamma-ray scattering and production. The basic physical principles involved in the construction of the models are reviewed, and results are presented in extensive graphs for low-energy gamma rays with the spectra of gamma-ray bursts, solar flares, the Crab pulsar, and 511-keV line radiation. It is shown that the model accurately reproduces the characteristics of atmospheric albedo radiation, including details of the angular distribution. The potential applicability of the Monte Carlo technique to studies of the near-earth radiation environment is indicated.

  20. Non-thermal Plasma Induces Apoptosis in Melanoma Cells via Production of Intracellular Reactive Oxygen Species

    PubMed Central

    Sensenig, Rachel; Kalghatgi, Sameer; Cerchar, Ekaterina; Fridman, Gregory; Shereshevsky, Alexey; Torabi, Behzad; Arjunan, Krishna Priya; Podolsky, Erica; Fridman, Alexander; Friedman, Gary; Azizkhan-Clifford, Jane; Brooks, Ari D.

    2012-01-01

    Non-thermal atmospheric pressure dielectric barrier discharge (DBD) plasma may provide a novel approach to treat malignancies via induction of apoptosis. The purpose of this study was to evaluate the potential of DBD plasma to induce apoptosis in melanoma cells. Melanoma cells were exposed to plasma at doses that did not induce necrosis, and cell viability and apoptotic activity were evaluated by Trypan blue exclusion test, Annexin-V/PI staining, caspase-3 cleavage, and TUNEL analysis. Trypan blue staining revealed that non-thermal plasma treatment significantly decreased the viability of cells in a dose-dependent manner 3 and 24 h after plasma treatment. Annexin-V/PI staining revealed a significant increase in apoptosis in plasma-treated cells at 24, 48, and 72 h post-treatment (p<0.001). Caspase-3 cleavage was observed 48 h post-plasma treatment at a dose of 15 J/cm2. TUNEL analysis of plasma-treated cells demonstrated an increase in apoptosis at 48 and 72 h post-treatment (p<0.001) at a dose of 15 J/cm2. Pre-treatment with N-acetyl-L-cysteine (NAC), an intracellular reactive oxygen species (ROS) scavenger, significantly decreased apoptosis in plasma-treated cells at 5 and 15 J/cm2. Plasma treatment induces apoptosis in melanoma cells through a pathway that appears to be dependent on production of intracellular ROS. DBD plasma production of intracellular ROS leads to dose-dependent DNA damage in melanoma cells, detected by ?-H2AX, which was completely abrogated by pre-treating cells with ROS scavenger, NAC. Plasma-induced DNA damage in turn may lead to the observed plasma-induced apoptosis. Since plasma is non-thermal, it may be used to selectively treat malignancies. PMID:21046465

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

    NASA Astrophysics Data System (ADS)

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

    2013-06-01

    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.

  2. Reactive organic gas emissions from livestock feed contribute significantly to ozone production in central California.

    PubMed

    Howard, Cody J; Kumar, Anuj; Malkina, Irina; Mitloehner, Frank; Green, Peter G; Flocchini, Robert G; Kleeman, Michael J

    2010-04-01

    The San Joaquin Valley (SJV) in California currently experiences some of the highest surface ozone (O(3)) concentrations in the United States even though it has a population density that is an order of magnitude lower than many urban areas with similar ozone problems. Previously unrecognized agricultural emissions may explain why O(3) concentrations in the SJV have not responded to traditional emissions control programs. In the present study, the ozone formation potentials (OFP) of livestock feed emissions were measured on representative field samples using a transportable smog chamber. Seven feeds were considered: cereal silage (wheat grain and oat grain), alfalfa silage, corn silage, high moisture ground corn (HMGC), almond shells, almond hulls, and total mixed ration (TMR = 55% corn silage, 16% corn grain, 8% almond hulls, 7% hay, 7% bran + seeds, and 5% protein + vitamins + minerals). The measured short-term OFP for each gram of reactive organic gas (ROG) emissions from all livestock feed was 0.17-0.41 g-O(3) per g-ROG. For reference, OFP of exhaust from light duty gasoline powered cars under the same conditions is 0.69 +/- 0.15 g-O(3) per g-ROG. Model calculations were able to reproduce the ozone formation from animal feeds indicating that the measured ROG compounds account for the observed ozone formation (i.e., ozone closure was achieved). Ethanol and other alcohol species accounted for more than 50% of the ozone formation for most types of feed. Aldehydes were also significant contributors for cereal silage, high moisture ground corn, and total mixed ration. Ozone production calculations based on feed consumption rates, ROG emissions rates, and OFP predict that animal feed emissions dominate the ROG contributions to ozone formation in the SJV with total production of 25 +/- 10 t O(3) day(-1). The next most significant ROG source of ozone production in the SJV is estimated to be light duty vehicles with total production of 14.3 +/- 1.4 t O(3) day(-1). The majority of the animal feed ozone formation is attributed to corn silage. Future work should be conducted to reduce the uncertainty of ROG emissions from animal feeds in the SJV and to include this significant source of ozone formation in regional airshed models. PMID:20192169

  3. HIV antiretroviral drug combination induces endothelial mitochondrial dysfunction and reactive oxygen species production, but not apoptosis

    SciTech Connect

    Jiang Bo; Hebert, Valeria Y.; Li, Yuchi; Mathis, J. Michael; Alexander, J. Steven; Dugas, Tammy R.

    2007-10-01

    Numerous reports now indicate that HIV patients administered long-term antiretroviral therapy (ART) are at a greater risk for developing cardiovascular diseases. Endothelial dysfunction is an initiating event in atherogenesis and may contribute to HIV-associated atherosclerosis. We previously reported that ART induces direct endothelial dysfunction in rodents. In vitro treatment of human umbilical vein endothelial cells (HUVEC) with ART indicated endothelial mitochondrial dysfunction and a significant increase in the production of reactive oxygen species (ROS). In this study, we determined whether ART-induced endothelial dysfunction is mediated via mitochondria-derived ROS and whether this mitochondrial injury culminates in endothelial cell apoptosis. Two major components of ART combination therapy, a nucleoside reverse transcriptase inhibitor and a protease inhibitor, were tested, using AZT and indinavir as representatives for each. Microscopy utilizing fluorescent indicators of ROS and mitochondria demonstrated the mitochondrial localization of ART-induced ROS. MnTBAP, a cell-permeable metalloporphyrin antioxidant, abolished ART-induced ROS production. As a final step in confirming the mitochondrial origin of the ART-induced ROS, HUVEC were transduced with a cytosolic- compared to a mitochondria-targeted catalase. Transduction with the mitochondria-targeted catalase was more effective than cytoplasmic catalase in inhibiting the ROS and 8-isoprostane (8-iso-PGF{sub 2{alpha}}) produced after treatment with either AZT or indinavir. However, both mitochondrial and cytoplasmic catalase attenuated ROS and 8-iso-PGF{sub 2{alpha}} production induced by the combination treatment, suggesting that in this case, the formation of cytoplasmic ROS may also occur, and thus, that the mechanism of toxicity in the combination treatment group may be different compared to treatment with AZT or indinavir alone. Finally, to determine whether ART-induced mitochondrial dysfunction and ROS production culminate in apoptosis, we performed the terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL), annexin V and 4',6-diamidino-2-phenylindole (DAPI) staining, and caspase-3 activity assays. However, none of these assays showed appreciable levels of ART-induced apoptosis. Our studies thus suggest that in endothelial cells, ART induces mitochondrial dysfunction with a concomitant increase in mitochondria-derived ROS. This compromised mitochondrial function may be one important factor culminating in endothelial dysfunction, without inducing an increase in apoptosis.

  4. Production and immunological analysis of IgE reactive recombinant egg white allergens expressed in Escherichia coli.

    PubMed

    Dhanapala, Pathum; Doran, Tim; Tang, Mimi L K; Suphioglu, Cenk

    2015-05-01

    IgE-mediated allergy to chicken egg affects a large number of children and adults worldwide. The current management strategy for egg allergy is strict avoidance, however this is impractical due to the presence of eggs in a range of foods and pharmaceutical products including vaccines. Strict avoidance also poses nutritional disadvantages due to high nutritional value of eggs. Allergen specific immunotherapy is being pursued as a curative treatment, in which an allergic individual is gradually exposed to the allergen to induce tolerance. Use of recombinant proteins for immunotherapy has been beneficial due to the purity of the recombinant proteins compared to natural proteins. In this study, we produced IgE reactive recombinant egg white proteins that can be used for future immunotherapy. Using E. coli as an expression system, we successfully produced recombinant versions of Gal d 1, 2 and 3, that were IgE reactive when tested against a pool of egg allergic patients' sera. The IgE reactivity indicates that these recombinant proteins are capable of eliciting an immune response, thus being potential candidates for immunotherapy. We have, for the first time, attempted to produce recombinant versions of all 4 major egg white allergens in E. coli, and successfully produced 3, with only Gal d 4 showing loss of IgE reactivity in the recombinant version. The results suggest that egg allergy in Australian populations may mainly be due to IgE reactivity to Gal d 3 and 4, while Gal d 1 shows higher IgE reactivity. This is the first report of a collective and comparative immunological analysis of all 4 egg white allergens. The significance of this study is the potential use of the IgE reactive recombinant egg white proteins in immunotherapy to treat egg allergic patients. PMID:25656803

  5. Multi-jet production rates in deep-inelastic muon-proton scattering

    SciTech Connect

    Salgado, C.W.; E665 Collaboration

    1992-10-01

    Measurements of forward multi-jet production rates in deep-inelastic muonproton scattering are presented. Data were taken with a 490 GeV muon beam incident on a hydrogen target. Jets were defined using the JADE jet finding algorithm. The measured rates are presented as function of W, the hadronic center-of-mass energy and the jet resolution parameter, y{sub cut}, in energies up to W=33 GeV. Good agreement is found in comparisons with predictions of the QCD-inspired Lund Monte Carlo models. Non-perturbative QCD production mechanisms, inside the Lund Model, can not reproduce the results for energies greater than W {approx_equal} 20 GeV. Sensitivities of the jet rate measurements to the low x (x {approx_equal} 0.02) gluon content of the nucleon and the evolution of {alpha}{sub s}, are studied.

  6. Effect of chemical product yield uncertainties on reactivities of VOCs and emissions from reformulated gasolines and methanol fuels

    SciTech Connect

    Yang, Y.J.; Stockwell, W.R.; Milford, J.B.

    1996-04-01

    To account for differences in exhaust composition that arise with the use of fuels other than conventional gasoline, California regulations apply reactivity adjustment factors (RAFs) to emissions standards for new motor vehicles. The RAFs are based on estimates of the sensitivity of ozone formation to each of the individual organic compounds in the exhaust. In this study, uncertainties have been estimated for the incremental reactivities of individual organic compounds and for RAFs for motor vehicle exhaust, accounting for uncertainties in chemical rate parameters and product yields and for variability in exhaust composition. Uncertainties (1{sigma}) in incremental reactivities of individual compounds range from about 25 to 75% of mean estimates and are typically about 10% higher than previous estimates obtained by considering independent rate parameters as the only source of uncertainty in the chemical mechanism. The incremental reactivities of relatively rapidly reacting compounds are sensitive to the peroxy radical yields in their primary oxidation reactions. RAF values of 0.87{+-}0.11(1{sigma}) and 0.42{+-}0.06, respectively, are calculated for exhaust emissions from a test gasoline with low aromatics and low olefins content, and from an 85% methanol, 15% gasoline blend. The RAF values show little sensitivity to product yield uncertainties. 8 refs., 2 figs., 6 tabs.

  7. Orally absorbed reactive glycation products (glycotoxins): an environmental risk factor in diabetic nephropathy.

    PubMed

    Koschinsky, T; He, C J; Mitsuhashi, T; Bucala, R; Liu, C; Buenting, C; Heitmann, K; Vlassara, H

    1997-06-10

    Endogenous advanced glycation endproducts (AGEs) include chemically crosslinking species (glycotoxins) that contribute to the vascular and renal complications of diabetes mellitus (DM). Renal excretion of the catabolic products of endogenous AGEs is impaired in patients with diabetic or nondiabetic kidney disease (KD). The aim of this study was to examine the oral absorption and renal clearance kinetics of food AGEs in DM with KD and whether circulating diet-derived AGEs contain active glycotoxins. Thirty-eight diabetics (DM) with or without KD and five healthy subjects (NL) received a single meal of egg white (56 g protein), cooked with (AGE-diet) or without fructose (100 g) (CL-diet). Serum and urine samples, collected for 48 hr, were monitored for AGE immunoreactivity by ELISA and for AGE-specific crosslinking reactivity, based on complex formation with 125I-labeled fibronectin. The AGE-diet, but not the CL-diet, produced distinct elevations in serum AGE levels in direct proportion to amount ingested (r = 0.8, P < 0.05): the area under the curve for serum ( approximately 10% of ingested AGE) correlated directly with severity of KD; renal excretion of dietary AGE, although normally incomplete (only approximately 30% of amount absorbed), in DM it correlated inversely with degree of albuminuria, and directly with creatinine clearance (r = 0.8, P < 0.05), reduced to <5% in DM with renal failure. Post-AGE-meal serum exhibited increased AGE-crosslinking activity (two times above baseline serum AGE, three times above negative control), which was inhibited by aminoguanidine. In conclusion, (i) the renal excretion of orally absorbed AGEs is markedly suppressed in diabetic nephropathy patients, (ii) daily influx of dietary AGEs includes glycotoxins that may constitute an added chronic risk for renal-vascular injury in DM, and (iii) dietary restriction of AGE food intake may greatly reduce the burden of AGEs in diabetic patients and possibly improve prognosis. PMID:9177242

  8. Regulation of Rac1 and Reactive Oxygen Species Production in Response to Infection of Gastrointestinal Epithelia.

    PubMed

    den Hartog, Gerco; Chattopadhyay, Ranajoy; Ablack, Amber; Hall, Emily H; Butcher, Lindsay D; Bhattacharyya, Asima; Eckmann, Lars; Harris, Paul R; Das, Soumita; Ernst, Peter B; Crowe, Sheila E

    2016-01-01

    Generation of reactive oxygen species (ROS) during infection is an immediate host defense leading to microbial killing. APE1 is a multifunctional protein induced by ROS and after induction, protects against ROS-mediated DNA damage. Rac1 and NAPDH oxidase (Nox1) are important contributors of ROS generation following infection and associated with gastrointestinal epithelial injury. The purpose of this study was to determine if APE1 regulates the function of Rac1 and Nox1 during oxidative stress. Gastric or colonic epithelial cells (wild-type or with suppressed APE1) were infected with Helicobacter pylori or Salmonella enterica and assessed for Rac1 and NADPH oxidase-dependent superoxide production. Rac1 and APE1 interactions were measured by co-immunoprecipitation, confocal microscopy and proximity ligation assay (PLA) in cell lines or in biopsy specimens. Significantly greater levels of ROS were produced by APE1-deficient human gastric and colonic cell lines and primary gastric epithelial cells compared to control cells after infection with either gastric or enteric pathogens. H. pylori activated Rac1 and Nox1 in all cell types, but activation was higher in APE1 suppressed cells. APE1 overexpression decreased H. pylori-induced ROS generation, Rac1 activation, and Nox1 expression. We determined that the effects of APE1 were mediated through its N-terminal lysine residues interacting with Rac1, leading to inhibition of Nox1 expression and ROS generation. APE1 is a negative regulator of oxidative stress in the gastrointestinal epithelium during bacterial infection by modulating Rac1 and Nox1. Our results implicate APE1 in novel molecular interactions that regulate early stress responses elicited by microbial infections. PMID:26761793

  9. Ferrocenes as potential chemotherapeutic drugs: Synthesis, cytotoxic activity, reactive oxygen species production and micronucleus assay

    PubMed Central

    Prez, Wanda I.; Soto, Yarelys; Ortz, Carmen; Matta, Jaime; Melndez, Enrique

    2014-01-01

    Three new ferrocene complexes were synthesized with 4-(1H-pyrrol-1-yl)phenol group appended to one of the Cp ring. These are: 1,1?-4-(1H-pyrrol-1-yl)phenyl ferrocenedicarboxylate, (Fc-(CO2-Ph-4-Py)2), 1,4-(1H-pyrrol-1-yl)phenyl, 1?-carboxyl ferrocenecarboxylate (Fc-(CO2-Ph-4-Py)CO2H) and 4-(1H-pyrrol-1-yl)phenyl ferroceneacetylate (Fc-CH2CO2-Ph-4-Py). The new species were characterized by standard analytical methods. Cyclic voltammetry experiments showed that Fc-CH2CO2-Ph-4-Py has redox potential very similar to the Fc/Fc+ redox couple whereas Fc-(CO2-Ph-4-Py)2 and Fc-(CO2-Ph-4-Py)CO2H have redox potentials of over 400 mV higher than Fc/Fc+ redox couple. The in vitro studies on Fc-(CO2-Ph-4-Py)2 and Fc-(CO2-Ph-4-Py)CO2H revealed that these two compounds have moderate anti-proliferative activity on MCF-7 breast cancer cell line. In contrast Fc-CH2CO2-Ph-4-Py which displayed low anti-proliferative activity. In the HT-29 colon cancer cell line, the new species showed low anti-proliferaive activity. Cytokinesis-block micronucleus assay (CBMN) was performed on these ferrocenes and it was determined they induce micronucleus formation on binucleated cells and moderate genotoxic effects on the MCF-7 breast cancer cell line. There is a correlation between the IC50 values of the ferrocenes and the amount of micronucleus formation activity on binucleated cells and the reactive oxygen species (ROS) production on MCF-7 cell line. PMID:25555734

  10. Ferrocenes as potential chemotherapeutic drugs: synthesis, cytotoxic activity, reactive oxygen species production and micronucleus assay.

    PubMed

    Prez, Wanda I; Soto, Yarelys; Ortz, Carmen; Matta, Jaime; Melndez, Enrique

    2015-02-01

    Three new ferrocene complexes were synthesized with 4-(1H-pyrrol-1-yl)phenol group appended to one of the Cp ring. These are: 1,1'-4-(1H-pyrrol-1-yl)phenyl ferrocenedicarboxylate, ('Fc-(CO2-Ph-4-Py)2'), 1,4-(1H-pyrrol-1-yl)phenyl, 1'-carboxyl ferrocenecarboxylate ('Fc-(CO2-Ph-4-Py)CO2H') and 4-(1H-pyrrol-1-yl)phenyl ferroceneacetylate ('Fc-CH2CO2-Ph-4-Py'). The new species were characterized by standard analytical methods. Cyclic voltammetry experiments showed that Fc-CH2CO2-Ph-4-Py has redox potential very similar to the Fc/Fc(+) redox couple whereas Fc-(CO2-Ph-4-Py)2 and Fc-(CO2-Ph-4-Py)CO2H have redox potentials of over 400 mV higher than Fc/Fc(+) redox couple. The in vitro studies on Fc-(CO2-Ph-4-Py)2 and Fc-(CO2-Ph-4-Py)CO2H revealed that these two compounds have moderate anti-proliferative activity on MCF-7 breast cancer cell line. In contrast Fc-CH2CO2-Ph-4-Py which displayed low anti-proliferative activity. In the HT-29 colon cancer cell line, the new species showed low anti-proliferative activity. Cytokinesis-block micronucleus assay (CBMN) was performed on these ferrocenes and it was determined they induce micronucleus formation on binucleated cells and moderate genotoxic effects on the MCF-7 breast cancer cell line. There is a correlation between the IC50 values of the ferrocenes and the amount of micronucleus formation activity on binucleated cells and the reactive oxygen species (ROS) production on MCF-7 cell line. PMID:25555734

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    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.

  12. Regulation of Rac1 and Reactive Oxygen Species Production in Response to Infection of Gastrointestinal Epithelia

    PubMed Central

    Ablack, Amber; Hall, Emily H.; Butcher, Lindsay D.; Bhattacharyya, Asima; Eckmann, Lars; Harris, Paul R.; Das, Soumita; Ernst, Peter B.; Crowe, Sheila E.

    2016-01-01

    Generation of reactive oxygen species (ROS) during infection is an immediate host defense leading to microbial killing. APE1 is a multifunctional protein induced by ROS and after induction, protects against ROS-mediated DNA damage. Rac1 and NAPDH oxidase (Nox1) are important contributors of ROS generation following infection and associated with gastrointestinal epithelial injury. The purpose of this study was to determine if APE1 regulates the function of Rac1 and Nox1 during oxidative stress. Gastric or colonic epithelial cells (wild-type or with suppressed APE1) were infected with Helicobacter pylori or Salmonella enterica and assessed for Rac1 and NADPH oxidase-dependent superoxide production. Rac1 and APE1 interactions were measured by co-immunoprecipitation, confocal microscopy and proximity ligation assay (PLA) in cell lines or in biopsy specimens. Significantly greater levels of ROS were produced by APE1-deficient human gastric and colonic cell lines and primary gastric epithelial cells compared to control cells after infection with either gastric or enteric pathogens. H. pylori activated Rac1 and Nox1 in all cell types, but activation was higher in APE1 suppressed cells. APE1 overexpression decreased H. pylori-induced ROS generation, Rac1 activation, and Nox1 expression. We determined that the effects of APE1 were mediated through its N-terminal lysine residues interacting with Rac1, leading to inhibition of Nox1 expression and ROS generation. APE1 is a negative regulator of oxidative stress in the gastrointestinal epithelium during bacterial infection by modulating Rac1 and Nox1. Our results implicate APE1 in novel molecular interactions that regulate early stress responses elicited by microbial infections. PMID:26761793

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

    SciTech Connect

    Lu Zhun; Schmidt, Ivan

    2009-08-04

    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.

  14. Chemical Characterization and Reactivity Testing of Fuel-Oxidizer Reaction Product (Test Report)

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The product of incomplete reaction of monomethylhydrazine (MMH) and nitrogen tetroxide (NTO) propellants, or fuel-oxidizer reaction product (FORP), has been hypothesized as a contributory cause of an anomaly which occurred in the chamber pressure (PC) transducer tube on the Reaction Control Subsystem (RCS) aft thruster 467 on flight STS-51. A small hole was found in the titanium-alloy PC tube at the first bend below the pressure transducer. It was surmised that the hole may have been caused by heat and pressure resulting from ignition of FORP. The NASA Johnson Space Center (JSC) White Sands Test Facility (WSTF) was requested to define the chemical characteristics of FORP, characterize its reactivity, and simulate the events in a controlled environment which may have lead to the Pc-tube failure. Samples of FORP were obtained from the gas-phase reaction of MMH with NTO under laboratory conditions, the pulsed firings of RCS thrusters with modified PC tubes using varied oxidizer or fuel lead times, and the nominal RCS thruster firings at WSTF and Kaiser-Marquardt. Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), accelerating rate calorimetry (ARC), ion chromatography (IC), inductively coupled plasma (ICP) spectrometry, thermogravimetric analysis (TGA) coupled to FTIR (TGA/FTIR), and mechanical impact testing were used to qualitatively and quantitatively characterize the chemical, thermal, and ignition properties of FORP. These studies showed that the composition of FORP is variable but falls within a limited range of compositions that depends on the fuel loxidizer ratio at the time of formation, composition of the post-formation atmosphere (reducing or oxidizing), and reaction or postreaction temperature. A typical composition contains methylhydrazinium nitrate (MMHN), ammonium nitrate (AN), methylammonium nitrate (MAN), and trace amounts of hydrazinium nitrate and 1,1-dimethylhydrazinium nitrate. The thermal decomposition reactions of FORP compositions used in this study were unremarkable, Neither the various compositions of FORP, the pure major components of FORP, nor mixtures of FORP with propellant-system corrosion products showed any unusual thermal activity when decomposed under laboratory conditions. Off-limit thruster operations were simulated by rapid mixing of liquid MMH and liquid NTO in a confined space. The test hardware was constructed with pressure- and temperature-measurement devices to determine if the expected fuel oxidizer reaction would result in increased energy release when FORP, FORP constituents, or propellant-system corrosion products were present. These tests demonstrated that FORP, MMHN, AN, or Inconel corrosion products can induce a mixture of MMH and NTO to produce component-damaging energies. The simulation-test program was not extensive enough to provide statistical probabilities for these events but did show that such events can occur. Damaging events required FORP or metal salts to be present at the initial mixing of MMH and NTO. Based on the results of these studies, it is suggested that removal or mitigation of a buildup of these materials may decrease the incidence of these high-energy, potentially damaging events.

  15. Stress induced lipid production in Chlorella vulgaris: relationship with specific intracellular reactive species levels.

    PubMed

    Menon, Kavya R; Balan, Ranjini; Suraishkumar, G K

    2013-06-01

    Microalgae have significant potential to be an important alternative energy source, but the challenges to the commercialization of bio-oil from microalgae need to be overcome for the potential to be realized. The application of stress can be used to improve bio-oil yields from algae. Nevertheless, the understanding of stress effects is fragmented due to the lack of a suitable, direct quantitative marker for stress. The lack of understanding seems to have limited the development of stress based strategies to improve bio-oil yields, and hence the commercialization of microalgae-based bio-oil. In this study, we have proposed and used the specific intracellular reactive species levels (siROS) particularly hydroxyl and superoxide radical levels, separately, as direct, quantitative, markers for stress, irrespective of the type of stress induced. Although ROS reactions are extremely rapid, the siROS level can be assumed to be at pseudo-steady state compared to the time scales of metabolism, growth and production, and hence they can be effective stress markers at particular time points. Also, the specific intracellular (si-) hydroxyl and superoxide radical levels are easy to measure through fluorimetry. Interestingly, irrespective of the conditions employed in this study, that is, nutrient excess/limitation or different light wavelengths, the cell concentrations are correlated to the siROS levels in an inverse power law fashion. The composite plots of cell concentration (y) and siROS (x) yielded the correlations of y?=?k1 ??x(-0.7) and y?=?k2 ??x(-0.79) , for si-hydroxyl and si-superoxide radical levels, respectively. The specific intracellular (si-) neutral lipid levels, which determine the bio-oil productivity, are related in a direct power law fashion to the specific hydroxyl radical levels. The composite plot of si-neutral lipid levels (z) and si-hydroxyl radical level (x) yielded a correlation of z?=?k3 ??x(0.65) . More interestingly, a nutrient shift caused a significant change in the sensitivity of neutral lipid accumulation to the si-hydroxyl radical levels. PMID:23297178

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

    PubMed

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

    2013-12-01

    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

  17. Reactive Arthritis

    MedlinePLUS

    ... Reactive Arthritis Find a Clinical Trial Journal Articles Reactive Arthritis October 2013 Questions and Answers about Reactive Arthritis This publication contains general information about reactive arthritis. ...

  18. Patterns of accumulation of miRNAs encoded by herpes simplex virus during productive infection, latency, and on reactivation

    PubMed Central

    Du, Te; Han, Zhiyuan; Zhou, Guoying; Roizman, Bernard

    2015-01-01

    The key events in herpes simplex virus (HSV) infections are (i) replication at a portal of entry into the body modeled by infection of cultured cells; (ii) establishment of a latent state characterized by a sole latency-associated transcript and microRNAs (miRNAs) modeled in murine peripheral ganglia 30 d after inoculation; and (iii) reactivation from the latent state modeled by excision and incubation of ganglia in medium containing anti-NGF antibody for a timespan of a single viral replicative cycle. In this report, we examine the pattern of synthesis and accumulation of 18 HSV-1 miRNAs in the three models. We report the following: (i) H2-3P, H3-3P, H4-3P, H5-3P, H6-3P, and H7-5P accumulated in ganglia harboring latent virus. All but H4-3P were readily detected in productively infected cells, and most likely they originate from three transcriptional units. (ii) H8-5P, H15, H17, H18, H26, and H27 accumulated during reactivation. Of this group, only H26 and H27 could be detected in productively infected cells. (iii) Of the 18 we have examined, only 10 miRNAs were found to accumulate above background levels in productively infected cells. The disparity in the accumulation of miRNAs in cell culture and during reactivation may reflect differences in the patterns of regulation of viral gene expression during productive infection and during reactivation from the latent state. PMID:25535379

  19. Effects of moderate electrical stimulation on reactive species production by primary rat skeletal muscle cells: cross talk between superoxide and nitric oxide production.

    PubMed

    Lambertucci, Rafael Herling; Silveira, Leonardo Dos Reis; Hirabara, Sandro Massao; Curi, Rui; Sweeney, Gary; Pithon-Curi, Tania Cristina

    2012-06-01

    The effects of a moderate electrical stimulation on superoxide and nitric oxide production by primary cultured skeletal muscle cells were evaluated. The involvement of the main sites of these reactive species production and the relationship between superoxide and nitric oxide production were also examined. Production of superoxide was evaluated by cytochrome c reduction and dihydroethidium oxidation assays. Electrical stimulation increased superoxide production after 1 h incubation. A xanthine oxidase inhibitor caused a partial decrease of superoxide generation and a significant amount of mitochondria-derived superoxide was also observed. Nitric oxide production was assessed by nitrite measurement and by using 4,5-diaminofluorescein diacetate (DAF-2-DA) assay. Using both methods an increased production of nitric oxide was obtained after electrical stimulation, which was also able to induce an increase of iNOS content and NF-κB activation. The participation of superoxide in nitric oxide production was investigated by incubating cells with DAF-2-DA in the presence or absence of electrical stimulation, a superoxide generator system (xanthine-xanthine oxidase), a mixture of NOS inhibitors and SOD-PEG. Our data show that the induction of muscle contraction by a moderate electrical stimulation protocol led to an increased nitric oxide production that can be controlled by superoxide generation. The cross talk between these reactive species likely plays a role in exercise-induced maintenance and adaptation by regulating muscular glucose metabolism, force of contraction, fatigue, and antioxidant systems activities. PMID:21898396

  20. Evidence for photochemical production of reactive oxygen species in desert soils.

    PubMed

    Georgiou, Christos D; Sun, Henry J; McKay, Christopher P; Grintzalis, Konstantinos; Papapostolou, Ioannis; Zisimopoulos, Dimitrios; Panagiotidis, Konstantinos; Zhang, Gaosen; Koutsopoulou, Eleni; Christidis, George E; Margiolaki, Irene

    2015-01-01

    The combination of intense solar radiation and soil desiccation creates a short circuit in the biogeochemical carbon cycle, where soils release significant amounts of CO2 and reactive nitrogen oxides by abiotic oxidation. Here we show that desert soils accumulate metal superoxides and peroxides at higher levels than non-desert soils. We also show the photogeneration of equimolar superoxide and hydroxyl radical in desiccated and aqueous soils, respectively, by a photo-induced electron transfer mechanism supported by their mineralogical composition. Reactivity of desert soils is further supported by the generation of hydroxyl radical via aqueous extracts in the dark. Our findings extend to desert soils the photogeneration of reactive oxygen species by certain mineral oxides and also explain previous studies on desert soil organic oxidant chemistry and microbiology. Similar processes driven by ultraviolet radiation may be operating in the surface soils on Mars. PMID:25960012

  1. 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)

    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

    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.

  2. Moderate dependence of reactive oxygen species production on membrane potential in avian muscle mitochondria oxidizing glycerol 3-phosphate.

    PubMed

    Kikusato, Motoi; Toyomizu, Masaaki

    2015-11-01

    Mitochondria are a major source of reactive oxygen species production in cells, and the production level is sensitive to the magnitude of the membrane potential (??). The present study investigated the level of superoxide production in mitochondria oxidizing glycerol 3-phosphate (GP) and its dependence on ?? in isolated avian muscle mitochondria. The levels of superoxide produced in mitochondria oxidizing GP were lower than those obtained with succinate and were similar to those obtained with NADH-linked substrates (glutamate/malate/pyruvate). The dependence of superoxide production on ?? in mitochondria oxidizing GP was lower than that of mitochondria oxidizing succinate, and a weak dependence of GP-supported superoxide production on ?? was observed in the presence of NADH-linked substrates or succinate. These results suggest that the levels of superoxide generated in response to GP are quantitatively low, but they are unsusceptible to changes in ?? in avian muscle mitochondria. PMID:26335765

  3. Mechanism of pion production in {alpha}p scattering at 1 GeV/nucleon

    SciTech Connect

    Alkhazov, G. D.; Prokofiev, A. N. Smirnov, I. B.; Strokovsky, E. A.

    2012-09-15

    An analysis of the experimental data on one-pion and two-pion production in the p({alpha}, {alpha} Prime )X reaction studied in a semi-exclusive experiment at an energy of E{sub {alpha}} = 4.2 GeV has been performed. The obtained results demonstrate that the inelastic {alpha}-particle scattering on the proton at the energy of the experiment proceeds either through excitation and decay of the {Delta} resonance in the projectile {alpha} particle, or through excitation in the target proton of the Roper resonance, which decays into a nucleon and a pion, or a nucleon and a {sigma} meson-a system of two pions in the isospin I = 0, S-wave state.

  4. Production of exclusive dijets in diffractive deep inelastic scattering at HERA

    NASA Astrophysics Data System (ADS)

    Abramowicz, H.; Abt, I.; Adamczyk, L.; Adamus, M.; Antonelli, S.; Aushev, V.; Aushev, Y.; Behnke, O.; Behrens, U.; Bertolin, A.; Bloch, I.; Boos, E. G.; Borras, K.; Brock, I.; Brook, N. H.; Brugnera, R.; Bruni, A.; Bussey, P. J.; Caldwell, A.; Capua, M.; Catterall, C. D.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cooper-Sarkar, A. M.; Corradi, M.; Corriveau, F.; Dementiev, R. K.; Devenish, R. C. E.; Dolinska, G.; Dusini, S.; Figiel, J.; Foster, B.; Gach, G.; Gallo, E.; Garfagnini, A.; Geiser, A.; Gizhko, A.; Gladilin, L. K.; Golubkov, Yu. A.; Grebenyuk, J.; Gregor, I.; Grzelak, G.; Gueta, O.; Guzik, M.; Hain, W.; Hochman, D.; Hori, R.; Ibrahim, Z. A.; Iga, Y.; Ishitsuka, M.; Iudin, A.; Januschek, F.; Jomhari, N. Z.; Kadenko, I.; Kananov, S.; Karshon, U.; Kaur, M.; Kaur, P.; Kisielewska, D.; Klanner, R.; Klein, U.; Kondrashova, N.; Kononenko, O.; Korol, Ie.; Korzhavina, I. A.; Kotański, A.; Kötz, U.; Kovalchuk, N.; Kowalski, H.; Krupa, B.; Kuprash, O.; Kuze, M.; Levchenko, B. B.; Levy, A.; Libov, V.; Limentani, S.; Lisovyi, M.; Lobodzinska, E.; Löhr, B.; Lohrmann, E.; Longhin, A.; Lontkovskyi, D.; Lukina, O. Yu.; Makarenko, I.; Malka, J.; Mergelmeyer, S.; Mohamad Idris, F.; Mohammad Nasir, N.; Myronenko, V.; Nagano, K.; Nobe, T.; Notz, D.; Nowak, R. J.; Onishchuk, Yu.; Paul, E.; Perlański, W.; Pokrovskiy, N. S.; Przybycień, M.; Roloff, P.; Rubinsky, I.; Ruspa, M.; Saxon, D. H.; Schioppa, M.; Schmidke, W. B.; Schneekloth, U.; Schörner-Sadenius, T.; Shcheglova, L. M.; Shevchenko, R.; Shkola, O.; Shyrma, Yu.; Singh, I.; Skillicorn, I. O.; Słomiński, W.; Solano, A.; Stanco, L.; Stefaniuk, N.; Stern, A.; Stopa, P.; Sztuk-Dambietz, J.; Szuba, D.; Szuba, J.; Tassi, E.; Tokushuku, K.; Tomaszewska, J.; Trofymov, A.; 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.; Żarnecki, A. F.; Zawiejski, L.; Zenaiev, O.; Zhautykov, B. O.; Zhmak, N.; Zotkin, D. S.

    2016-01-01

    Production of exclusive dijets in diffractive deep inelastic e^± p scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 372 pb^{-1}. The measurement was performed for γ ^{*}- p centre-of-mass energies in the range 90< W < {250} {GeV} and for photon virtualities Q^2 > {25} {GeV2}. Energy flows around the jet axis are presented. The cross section is presented as a function of β and φ , where β =x/x_IP, x is the Bjorken variable and x_IP is the proton fractional longitudinal momentum loss. The angle φ is defined by the γ ^{*}-dijet plane and the γ ^{*}-e^± plane in the rest frame of the diffractive final state. The φ cross section is measured in bins of β . The results are compared to predictions from models based on different assumptions about the nature of the diffractive exchange.

  5. The exclusive production of Rho mesons in deep inelastic scattering at HERA

    NASA Astrophysics Data System (ADS)

    Bulmahn, Jeffrey W.

    1997-11-01

    The exclusive production of ?0 mesons in deep inelastic scattering (DIS) was studied using data obtained with the ZEUS detector from the 1994 HERA run. The cross section for this process has been determined in the range 3 < Q2 < 30 [ GeV2] and 42 < W < 141 [ GeV], subject to the restrictions pT2 < 0.6 [ GeV2] and 0.4 < M/pi?/

  6. Recent advances and open questions in neutrino-induced quasi-elastic scattering and single photon production

    NASA Astrophysics Data System (ADS)

    Garvey, G. T.; Harris, D. A.; Tanaka, H. A.; Tayloe, R.; Zeller, G. P.

    2015-06-01

    The study of neutrino-nucleus interactions has recently seen rapid development with a new generation of accelerator-based neutrino experiments employing medium and heavy nuclear targets for the study of neutrino oscillations. A few unexpected results in the study of quasi-elastic scattering and single photon production have spurred a revisiting of the underlying nuclear physics and connections to electron-nucleus scattering. A thorough understanding and resolution of these issues is essential for future progress in the study of neutrino oscillations. A recent workshop hosted by the Institute of Nuclear Theory at the University of Washington (INT-13-54W) examined experimental and theoretical developments in neutrino-nucleus interactions and related measurements from electron and pion scattering. We summarize the discussions at the workshop pertaining to the aforementioned issues in quasi-elastic scattering and single photon production, particularly where there was consensus on the highest priority issues to be resolved and the path towards resolving them. charged current quasi-elastic scattering and single photon production. Both topics have seen intriguing experimental observations that have instigated a thorough re-investigation of the fundamental nuclear physics involved in understanding and modeling these processes. Furthermore, both processes are critical in interpreting neutrino oscillation measurements, where the intrinsic properties of neutrinos are studied through interference effects using neutrino-nucleus interactions. As rapid progress is made in neutrino oscillation measurements, commensurate developments in understanding and improving the modeling of the underlying nuclear physics will need to keep pace. >We begin with a brief introduction to neutrino charged current quasi-elastic scattering, followed by a review of recent experimental studies of this process, the intimately related issues in electron-nucleus scattering, and the theoretical developments essential towards understanding both processes. We then discuss the progress in single photon production in neutrino neutral current interactions, before summarizing the next steps towards resolving the remaining issues.

  7. Oxidants, antioxidants, and the beneficial roles of exercise-induced production of reactive species.

    PubMed

    Gomes, Elisa Couto; Silva, Albená Nunes; de Oliveira, Marta Rubino

    2012-01-01

    This review offers an overview of the influence of reactive species produced during exercise and their effect on exercise adaptation. Reactive species and free radicals are unstable molecules that oxidize other molecules in order to become stable. Although they play important roles in our body, they can also lead to oxidative stress impairing diverse cellular functions. During exercise, reactive species can be produced mainly, but not exclusively, by the following mechanisms: electron leak at the mitochondrial electron transport chain, ischemia/reperfusion and activation of endothelial xanthine oxidase, inflammatory response, and autooxidation of catecholamines. Chronic exercise also leads to the upregulation of the body's antioxidant defence mechanism, which helps minimize the oxidative stress that may occur after an acute bout of exercise. Recent studies show a beneficial role of the reactive species, produced during a bout of exercise, that lead to important training adaptations: angiogenesis, mitochondria biogenesis, and muscle hypertrophy. The adaptations occur depending on the mechanic, and consequently biochemical, stimulus within the muscle. This is a new area of study that promises important findings in the sphere of molecular and cellular mechanisms involved in the relationship between oxidative stress and exercise. PMID:22701757

  8. Structural Evolution of Iron Antimonides from Amorphous Precursors to Crystalline Products Studied by Total Scattering Techniques.

    PubMed

    Bauers, Sage R; Wood, Suzannah R; Jensen, Kirsten M Ø; Blichfeld, Anders B; Iversen, Bo B; Billinge, Simon J L; Johnson, David C

    2015-08-01

    Homogeneous reaction precursors may be used to form several solid-state compounds inaccessible by traditional synthetic routes, but there has been little development of techniques that allow for a priori prediction of what may crystallize in a given material system. Here, the local structures of FeSbx designed precursors are determined and compared with the structural motifs of their crystalline products. X-ray total scattering and atomic pair distribution function (PDF) analysis are used to show that precursors that first nucleate a metastable FeSb3 compound share similar local structure to the product. Interestingly, precursors that directly crystallize to thermodynamically stable FeSb2 products also contain local structural motifs of the metastable phase, despite their compositional disagreement. While both crystalline phases consist of distorted FeSb6 octahedra with Sb shared between either two or three octahedra as required for stoichiometry, a corner-sharing arrangement indicative of AX3-type structures is the only motif apparent in the PDF of either precursor. Prior speculation was that local composition controlled which compounds nucleate from amorphous intermediates, with different compositions favoring different local arrangements and hence different products. This data suggests that local environments in these amorphous intermediates may not be very sensitive to overall composition. This can provide insight into potential metastable phases which may form in a material system, even with a precursor that does not crystallize to the kinetically stabilized product. Determination of local structure in homogeneous amorphous reaction intermediates from techniques such as PDF can be a valuable asset in the development of systematic methods to prepare targeted solid-state compounds from designed precursors. PMID:26161946

  9. Sirtuin-3 (Sirt3) regulates skeletal muscle metabolism and insulin signaling via altered mitochondrial oxidation and reactive oxygen species production.

    PubMed

    Jing, Enxuan; Emanuelli, Brice; Hirschey, Matthew D; Boucher, Jeremie; Lee, Kevin Y; Lombard, David; Verdin, Eric M; Kahn, C Ronald

    2011-08-30

    Sirt3 is a member of the sirtuin family of protein deacetylases that is localized in mitochondria and regulates mitochondrial function. Sirt3 expression in skeletal muscle is decreased in models of type 1 and type 2 diabetes and regulated by feeding, fasting, and caloric restriction. Sirt3 knockout mice exhibit decreased oxygen consumption and develop oxidative stress in skeletal muscle, leading to JNK activation and impaired insulin signaling. This effect is mimicked by knockdown of Sirt3 in cultured myoblasts, which exhibit reduced mitochondrial oxidation, increased reactive oxygen species, activation of JNK, increased serine and decreased tyrosine phosphorylation of IRS-1, and decreased insulin signaling. Thus, Sirt3 plays an important role in diabetes through regulation of mitochondrial oxidation, reactive oxygen species production, and insulin resistance in skeletal muscle. PMID:21873205

  10. Room-Temperature Reactivity Of Silicon Nanocrystals With Solvents: The Case Of Ketone And Hydrogen Production From Secondary Alcohols: Catalysis?

    PubMed

    El-Demellawi, Jehad K; Holt, Christopher R; Abou-Hamad, Edy; Al-Talla, Zeyad A; Saih, Youssef; Chaieb, Sahraoui

    2015-07-01

    Although silicon nanoparticles dispersed in liquids are used in various applications ranging from biolabeling to hydrogen production, their reactivities with their solvents and their catalytic properties remain still unexplored. Here, we discovered that, because of their surface structures and mechanical strain, silicon nanoparticles react strongly with their solvents and may act as catalysts for the dehydrogenation, at room temperature, of secondary alcohols (e.g., isopropanol) into ketones and hydrogen. This catalytic reaction was monitored by gas chromatography, pH measurements, mass spectroscopy, and solid-state NMR. This discovery provides new understanding of the role played by silicon nanoparticles, and nanosilicon in general, in their reactivity in solvents in general, as well as being candidates in catalysis. PMID:26024366

  11. Uric acid and transforming growth factor in fructose-induced production of reactive oxygen species in skeletal muscle.

    PubMed

    Madlala, Hlengiwe P; Maarman, Gerald J; Ojuka, Edward

    2016-04-01

    The consumption of fructose, a major constituent of the modern diet, has raised increasing concern about the effects of fructose on health. Research suggests that excessive intake of fructose (>50 g/d) causes hyperuricemia, insulin resistance, mitochondrial dysfunction, de novo lipogenesis by the liver, and increased production of reactive oxygen species (ROS) in muscle. In a number of tissues, uric acid has been shown to stimulate the production of ROS via activation of transforming growth factor β1 and NADPH (nicotinamide adenine dinucleotide phosphate) oxidase 4. The role of uric acid in fructose-induced production of ROS in skeletal muscle, however, has not been investigated. This review examines the evidence for fructose-induced production of ROS in skeletal muscle, highlights proposed mechanisms, and identifies gaps in current knowledge. PMID:26946251

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

    PubMed

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

    2014-02-01

    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

  13. Computational Benchmark for Estimation of Reactivity Margin from Fission Products and Minor Actinides in PWR Burnup Credit

    SciTech Connect

    Wagner, J.C.

    2001-08-02

    This report proposes and documents a computational benchmark problem for the estimation of the additional reactivity margin available in spent nuclear fuel (SNF) from fission products and minor actinides in a burnup-credit storage/transport environment, relative to SNF compositions containing only the major actinides. The benchmark problem/configuration is a generic burnup credit cask designed to hold 32 pressurized water reactor (PWR) assemblies. The purpose of this computational benchmark is to provide a reference configuration for the estimation of the additional reactivity margin, which is encouraged in the U.S. Nuclear Regulatory Commission (NRC) guidance for partial burnup credit (ISG8), and document reference estimations of the additional reactivity margin as a function of initial enrichment, burnup, and cooling time. Consequently, the geometry and material specifications are provided in sufficient detail to enable independent evaluations. Estimates of additional reactivity margin for this reference configuration may be compared to those of similar burnup-credit casks to provide an indication of the validity of design-specific estimates of fission-product margin. The reference solutions were generated with the SAS2H-depletion and CSAS25-criticality sequences of the SCALE 4.4a package. Although the SAS2H and CSAS25 sequences have been extensively validated elsewhere, the reference solutions are not directly or indirectly based on experimental results. Consequently, this computational benchmark cannot be used to satisfy the ANS 8.1 requirements for validation of calculational methods and is not intended to be used to establish biases for burnup credit analyses.

  14. Degradation of reactive dyes in wastewater from the textile industry by ozone: analysis of the products by accurate masses.

    PubMed

    Constapel, Marc; Schellenträger, Marc; Marzinkowski, Joachim Michael; Gäb, Siegmar

    2009-02-01

    The present work describes the use of ozone to degrade selected reactive dyes from the textile industry and the analysis of the resulting complex mixture by liquid chromatography/mass spectrometry (LC-MS). To allow certain identification of the substances detected in the wastewater, the original dyes were also investigated either separately or in a synthetic mixture of three dyes (trichromie). Since the reactive dyes are hydrolyzed during the dyeing process, procedures for the hydrolysis were worked out first for the individual dyes. The ozonated solutions were concentrated by solid-phase extraction, which separated very polar or ionic substances from moderately polar degradation products. The latter, which are the primary degradation products, were investigated by liquid chromatography/mass spectrometry with a tandem quadrupole time-of-flight mass analyzer. Accurate masses, which in most cases could be determined with a deviation of products in the same run. With retention times, mass spectra, accurate masses, UV-vis spectra and, of course, knowledge of the structures of the original dyes, plausible structures could be proposed for most of the components of the moderately polar fraction. These structures were confirmed by 1H NMR in cases where it was practical to isolate the degradation products by preparative HPLC. PMID:19110293

  15. Chemical Reactivity of alpha-Pinene-derived Products in the Aqueous Phase: Implications on the Fate of Organic Nitrates

    NASA Astrophysics Data System (ADS)

    Rindelaub, J. D.; Hostetler, M. A.; Lipton, M. A.; Shepson, P. B.

    2014-12-01

    The production of organic nitrates has significant atmospheric importance due to the impact on regional air quality by influencing NOx lifetimes and ozone formation. Additionally, these low volatility compounds readily partition into the particle phase and are important contributors to secondary organic aerosol. Once in the aerosol phase, organic nitrates undergo further chemical reactions that govern their fate in the atmosphere and, consequently, their impact on air quality. Recent research indicates that the presence of water on aerosol particles has a major impact on the reactivity of organic nitrates and that condensed phase hydrolysis leads to the destruction of organic nitrate species, depending on structure. Despite this knowledge, the chemical mechanisms, products, product reactivity and volatility are still uncertain, negatively impacting our understanding of aerosol phase processing and the contribution to air quality. To further understand the atmospheric impact of aerosol phase hydrolysis, we analyzed both condensed phase hydrolysis reactions involving alpha-pinene-derived standards and alpha-pinene photochemical chamber reaction filter samples, using a suite of spectroscopic and mass spectrometric techniques. We were able to measure the pH-dependent hydrolysis rate constants for several types of organic nitrates and identify specific reaction products. The chemistry involved exhibits a strong dependence on pH, providing important mechanistic clues. The results of this study will significantly contribute to our knowledge of aerosol phase chemistry and the impact on regional air quality with respect to the fate of organic nitrate species.

  16. Momentum space saturation model for deep inelastic scattering and single inclusive hadron production

    NASA Astrophysics Data System (ADS)

    Basso, E. A. F.; Gay Ducati, M. B.; de Oliveira, E. G.

    2011-08-01

    We show how the Santana Amaral-Gay Ducati-Betemps-Soyez (AGBS) model, originally developed for deep inelastic scattering applied to HERA data on the proton structure function, can also describe the RHIC data on single inclusive hadron yield for d+Au and p+p collisions through a new simultaneous fit. The single inclusive hadron production is modeled through the color glass condensate, which uses the quark (and gluon) condensate amplitudes in momentum space. The AGBS model is also a momentum space model based on the asymptotic solutions of the Balitsky-Kovchegov equation, although a different definition of the Fourier transform is used. This aspect is overcome, and a description entirely in transverse momentum of both processes arises for the first time. The small difference between the simultaneous fit and the one for HERA data alone suggests that the AGBS model describes very well both kinds of processes and thus emerges as a good tool to investigate the inclusive hadron production data. We use this model for predictions at LHC energies, which agrees very well with available experimental data.

  17. Interaction of insulin with methyl tert-butyl ether promotes molten globule-like state and production of reactive oxygen species.

    PubMed

    Valipour, Masoumeh; Maghami, Parvaneh; Habibi-Rezaei, Mehran; Sadeghpour, Mostafa; Khademian, Mohamad Ali; Mosavi, Khadijeh; Sheibani, Nader; Moosavi-Movahedi, Ali Akbar

    2015-09-01

    Interaction of methyl tert-butyl ether (MTBE) with proteins is a new look at its potential adverse biological effects. When MTBE is released to the environment it enters the blood stream through inhalation, and could affect the properties of various proteins. Here we investigated the interaction of MTBE with insulin and its effect on insulin structural changes. Our results showed that insulin formed a molten globule (MG)-like structure in the presence of 8 ?M MTBE under physiological pH. The insulin structural changes were studied using spectroscopy methods, viscosity calculation, dynamic light scattering and differential scanning calorimetry. To delineate the mechanisms involved in MTBE-protein interactions, the formation of reactive oxygen specious (ROS) and formation of protein aggregates were measured. The chemiluminscence experiments revealed an increase in ROS production in the presence of MTBE especially in the MG-like state. These results were further confirmed by the aggregation tests, which indicated more aggregation of insulin at 40 ?M MTBE compared with 8 ?M. Thus, the formation of initial aggregates and exposure of the hydrophobic patches upon formation of the MG-like state in the presence of MTBE drives protein oxidation and ROS generation. PMID:26193678

  18. Pivotal Role of Reactive Oxygen Species in Differential Regulation of Lipopolysaccharide-Induced Prostaglandins Production in Macrophages

    PubMed Central

    Zhao, Guiqing; Yu, Rui; Deng, Jing; Zhao, Qiong; Li, Yongchao; Joo, Myungsoo; van Breemen, Richard B.; Christman, John W.

    2013-01-01

    Gram-negative bacterial endotoxin lipopolysaccharide (LPS) triggers the production of inflammatory cytokines, reactive oxygen species (ROS), and prostaglandins (PGs) by pulmonary macrophages. Here, we investigated if ROS influenced PGs production in response to LPS treatment in mouse bone marrow-derived macrophages (BMDM). We observed that pretreatment of BMDM with two structurally unrelated ROS scavengers, MnTMPyP and EUK-134, not only prevented LPS-induced ROS accumulation, but also attenuated the LPS-induced PGD2, but not PGE2, production. Conversely LPS-induced PGD2, but not PGE2, production, was potentiated with the cotreatment of BMDM with H2O2. These data suggest that ROS differentially regulate PGD2 and PGE2 production in BMDM. In addition, selective inhibition of the ROS generator NADPH oxidase (NOX) using either pharmacologic inhibitors or its p47phox subunit deficient mouse BMDM also attenuated LPS-induced PGD2, but not PGE2 production, suggesting the critical role of NOX-generated ROS in LPS-induced PGD2 production in BMDM. We further found that both hematopoietic PGD synthase (H-PGDS) siRNA and its inhibitor HQL-79, but not lipocalin PGDS (L-PGDS) siRNA and its inhibitor AT-56, significantly attenuated LPS-induced PGD2 production, suggesting that H-PGDS, but not L-PGDS, mediates LPS-induced PGD2 production in BMDM. Furthermore, data from our in vitro cell-free enzymatic studies showed that coincubation of the recombinant H-PGDS with either MnTMPyP, EUK-134, or catalase significantly decreased PGD2 production, whereas coincubation with H2O2 significantly increased PGD2 production. Taken together, our results show that LPS-induced NOX-generated ROS production differentially and specifically regulates the H-PGDS-mediated production of PGD2, but not PGE2, in mouse BMDM. PMID:23071105

  19. Increased resistin may suppress reactive oxygen species production and inflammasome activation in type 2 diabetic patients with pulmonary tuberculosis infection.

    PubMed

    Chao, Wen-Cheng; Yen, Chia-Liang; Wu, Ying-Hsun; Chen, Shin-Yi; Hsieh, Cheng-Yuan; Chang, Tsung-Chain; Ou, Horng-Yih; Shieh, Chi-Chang

    2015-03-01

    Although it has been known for decades that patients with type 2 diabetes mellitus (DM) are more susceptible to severe tuberculosis (TB) infection, the underlying immunological mechanisms remain unclear. Resistin, a protein produced by immune cells in humans, causes insulin resistance and has been implicated in inhibiting reactive oxygen species (ROS) production in leukocytes. Recent studies suggested that IL-1? production in patients with Mycobacteria tuberculosis infection correlates with inflammasome activation which may be regulated by ROS production in the immune cells. By investigating the level of resistin in different patient groups, we found that serum resistin levels were significantly higher in severe TB and DM-only groups when compared with mild TB cases and healthy controls. Moreover, elevation of serum resistin correlated with impairment of ROS production of neutrophils in patients with both DM and TB. In human macrophages, exogenous resistin inhibits the production of ROS which are important in the mycobacterium-induced inflammasome activation. Moreover, macrophages with defective ROS production had poor IL-1? production and ineffective control of mycobacteria growth. Our results suggest that increased resistin in severe TB and DM patients may suppress the mycobacterium-induced inflammasome activation through inhibiting ROS production by leukocytes. PMID:25528597

  20. NADPH oxidase-mediated reactive oxygen species production: subcellular localization and reassessment of its role in plant defense.

    PubMed

    Lherminier, Jeannine; Elmayan, Taline; Fromentin, Jrme; Elaraqui, Khadija Tantaoui; Vesa, Simona; Morel, Johanne; Verrier, Jean-Louis; Cailleteau, Bernard; Blein, Jean-Pierre; Simon-Plas, Franoise

    2009-07-01

    Chemiluminescence detection of reactive oxygen species (ROS) triggered in tobacco BY-2 cells by the fungal elicitor cryptogein was previously demonstrated to be abolished in cells transformed with an antisense construct of the plasma membrane NADPH oxidase, NtrbohD. Here, using electron microscopy, it has been confirmed that the first hydrogen peroxide production occurring a few minutes after challenge of tobacco cells with cryptogein is plasma membrane located and NtrbohD mediated. Furthermore, the presence of NtrbohD in detergent-resistant membrane fractions could be associated with the presence of NtrbohD-mediated hydrogen peroxide patches along the plasma membrane. Comparison of the subcellular localization of ROS in wild-type tobacco and in plants transformed with antisense constructs of NtrbohD revealed that this enzyme is also responsible for the hydrogen peroxide production occurring at the plasma membrane after infiltration of tobacco leaves with cryptogein. Finally, the reactivity of wild-type and transformed plants to the elicitor and their resistance against the pathogenic oomycete Phytophthora parasitica were examined. NtrbohD-mediated hydrogen peroxide production does not seem determinant for either hypersensitive response development or the establishment of acquired resistance but it is most likely involved in the signaling pathways associated with the protection of the plant cell. PMID:19522569

  1. Coulomb scattering in a 2D interacting electron gas and production of EPR pairs.

    PubMed

    Saraga, D S; Altshuler, B L; Loss, Daniel; Westervelt, R M

    2004-06-18

    We propose a setup to generate nonlocal spin Einstein-Podolsky-Rosen pairs via pair collisions in a 2D interacting electron gas, based on constructive two-particle interference in the spin-singlet channel at the pi/2 scattering angle. We calculate the scattering amplitude via the Bethe-Salpeter equation in the ladder approximation and small r(s) limit and find that the Fermi sea leads to a substantial renormalization of the bare scattering process. From the scattering length, we estimate the current of spin-entangled electrons and show that it is within experimental reach. PMID:15245120

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

    SciTech Connect

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

    2013-04-02

    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.

  3. Functional expression of plant alternative oxidase decreases antimycin A-induced reactive oxygen species production in human cells.

    PubMed

    Matsukawa, Kazushige; Kamata, Takashi; Ito, Kikukatsu

    2009-01-01

    Alternative oxidase (AOX) plays a pivotal role in cyanide-resistance respiration in the mitochondria of plants, fungi and some protists. Here we show that AOX from thermogenic skunk cabbage successfully conferred cyanide resistance to human cells. In galactose medium, HeLa cells with mitochondria-targeted AOX proteins were found to have significantly less reactive oxygen species production in response to antimycin-A exposure, a specific inhibitor of respiratory complex III. These results suggest that skunk cabbage AOX can be used to create an alternative respiration pathway, which might be important for therapy against various mitochondrial diseases. PMID:19059403

  4. Single-parton scattering versus double-parton scattering in the production of two cc pairs and charmed meson correlations at the LHC

    NASA Astrophysics Data System (ADS)

    van Hameren, Andreas; Maciu?a, Rafa?; Szczurek, Antoni

    2014-05-01

    We compare results of exact calculations of single-parton scattering (SPS) and double-parton scattering (DPS) for production of cccc and for D meson correlations. The SPS calculations are performed in collinear approximation with exact matrix element for gg?cccc and qq?cccc subprocesses. It is shown that the contribution of gluon-gluon subprocess is about factor 50 larger than that for quark-antiquark annihilation. The new results are compared with results of previous calculation with the approximate matrix element for gg?cccc in the high-energy approximation. The cross section for the present exact calculation is bigger only at small invariant masses and small rapidity difference between two c quarks (or two c antiquarks). We compare correlations in rapidities of two c (or two c) for DPS and SPS contributions. Finally, we compare our predictions for D mesons with recent results of the LHCb Collaboration for invariant mass, rapidity distance between mesons and dimeson invariant mass. The predicted shapes are similar to the measured ones, however, we still underpredict the experimental cross sections. Our new calculations clearly confirm the dominance of DPS in the production of events with double charm.

  5. Echinoderm reactive oxygen species (ROS) production measured by peroxidase, luminol-enhanced chemiluminescence (PLCL) as an immunotoxicological tool.

    PubMed

    Coteur, G; Danis, B; Dubois, P

    2005-01-01

    The importance of reactive oxygen species (ROS) production in invertebrate immunity prompted the use of this response in immunotoxicological studies in several taxa including marine organisms. In this chapter, we review the effects of environmental factors and contaminants such as heavy metals and polychlorinated biphenyls (PCBs) on the production of ROS by the main immune effector cells of echinoderms, the so-called amoebocytes. ROS production was measured by the peroxidase, luminol-enhanced chemiluminescence (PLCL) method. This method was found to predominantly reflect the production of superoxide anions and peroxides, among which hydrogen peroxide and peroxynitrite are the main species detected. Exogenous factors such as water temperature and salinity can influence this immune response in echinoderms. However, gender, handling stress and parasitism by a castrating ciliate apparently did not affect it. The impact of metals on ROS production differed greatly according to the duration and routes of exposure; in vitro and short-term in vivo exposures to metals caused an inhibition of this immune response, while the opposite effect was observed in a long-term in vivo exposure study. On the other hand, PCBs systematically had a stimulatory effect on ROS production independent of the echinoderm species or exposure routes. From the study of complex field contaminations, it appeared that contaminants released in the environment, such as metals, modulate starfish amoebocyte ROS production. This impact potentially represents a threat to the sustainability of natural populations of echinoderms and thereby to the stability of benthic ecosystems. PMID:17152694

  6. Optimizing Pulse Waveforms in Plasma Jets for Reactive Oxygen Species (ROS) Production

    NASA Astrophysics Data System (ADS)

    Norberg, Seth; Babaeva, Natalia Yu.; Kushner, Mark J.

    2012-10-01

    Reactive oxygen species (ROS) are desired in numerous applications from the destruction of harmful proteins and bacteria for sterilization in the medical field to taking advantage of the metastable characteristics of O2(^1?) to transfer energy to other species. Advances in atmospheric pressure plasma jets in recent years show the possibility of using this application as a source of reactive oxygen species. In this paper, we report on results from a computational investigation of atmospheric pressure plasma jets in a dielectric barrier discharge (DBD) configuration. The computer model used in this study, nonPDPSIM, solves transport equations for charged and neutral species, Poisson's equation for the electric potential, the electron energy conservation equation for the electron temperature, and Navier-Stokes equations for the neutral gas flow. A Monte Carlo simulation is used to track sheath accelerated secondary electrons emitted from surfaces and the energy of ions incident onto surfaces. Rate coefficients and transport coefficients for the bulk plasma are obtained from local solutions of Boltzmann's equation for the electron energy distribution. Radiation transport is addressed using a Green's function approach. Various waveforms for the voltage source were examined in analogy to spiker-sustainer systems used at lower gas pressures.

  7. J/ψ-pair production at large momenta: Indications for double parton scatterings and large αs5 contributions

    NASA Astrophysics Data System (ADS)

    Lansberg, Jean-Philippe; Shao, Hua-Sheng

    2015-12-01

    We demonstrate that the recent studies of J / ψ-pair production by CMS at the LHC and by D0 at the Tevatron reveal the presence of different production mechanisms in different kinematical regions. We find out that next-to-leading-order single parton scattering contributions at αs5 dominate the yield at large transverse momenta of the pair. Our analysis further emphasises the importance of double parton scatterings - which are expected to dominate the yield at large J / ψ-rapidity differences - at large invariant masses of the pair in the CMS acceptance, and thereby solve a large discrepancy between the theory and the CMS data. In addition, we provide the first exact - gauge-invariant and infrared-safe - evaluation of a class of leading-PT (PT-4) next-to-next-to-leading-order contributions at αs6, which can be relevant in the region of large values of PTmin = min ⁡ (PT1 ,PT2). Finally, we derive simple relations for the feed-down fractions from the production of an excited charmonium state with a J / ψ in the case of the dominance of the double parton scatterings, which significantly deviate from those for single parton scatterings. Such relations can be used to discriminate these extreme scenarios, either DPS or SPS dominance.

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

    NASA Astrophysics Data System (ADS)

    Kleinman, L. I.; Daum, P. H.; Imre, D.; Lee, Y.-N.; Nunnermacker, L. J.; Springston, S. R.; Weinstein-Lloyd, J.; Rudolph, J.

    2002-05-01

    Observations of ozone (O3) and O3 precursors taken from aircraft flights over Houston, TX, Nashville, TN; New York, NY; Phoenix, AZ, and Philadelphia, PA show that high concentrations of reactive volatile organic compounds (VOCs) in the Houston atmosphere lead to calculated O3 production rates that are 2 to 5 times higher than in the other 4 cities even though NOx concentrations are comparable. Within the Houston metropolitan area, concentrations of VOCs and O3 production rates are highest in the Ship Channel region; the location of one of the largest petrochemical complexes in the world. As a consequence the concentration of O3 in the Houston metropolitan area has recently exceeded 250 ppb, the highest value observed in the U.S within the past 5 years.

  9. Identification of 4-quinolone derivatives as inhibitors of reactive oxygen species production from human umbilical vein endothelial cells.

    PubMed

    Onda, Kenichi; Narazaki, Fumie; Ishibashi, Naoki; Nakanishi, Keita; Sawada, Yuki; Imamura, Ken-ichiro; Momose, Kazuhiro; Furukawa, Shigetada; Shimada, Yoshiaki; Moriguchi, Hiroyuki; Yuda, Masamichi; Kayakiri, Hiroshi; Ohta, Mitsuaki

    2011-11-15

    Oxidative stress is widely recognized as being associated with a number of disorders, including metabolic dysfunction and atherosclerosis. A series of substituted 4-quinolone derivatives were prepared and evaluated as inhibitors of reactive oxygen species (ROS) production from human umbilical vein endothelial cells (HUVECs). One compound in particular, 2-({[4-(3-hydroxy-3-methylbutoxy)pyridin-2-yl]oxy}methyl)-3-methylquinolin-4(1H)-one (25b), inhibited ROS production from HUVECs with an IC(50) of 140 nM. This compound also exhibited low CYP2D6 inhibitory activity, high aqueous solubility, and good in vitro metabolic stability. An in vivo pharmacokinetic study of this compound in SD rats revealed high oral bioavailability and a long plasma half-life. PMID:21963985

  10. Smac mimetic with TNF-? targets Pim-1 isoforms and reactive oxygen species production to abrogate transformation from blebbishields.

    PubMed

    Jinesh, Goodwin G; Laing, Naomi M; Kamat, Ashish M

    2016-01-01

    Cancer cells are capable of sphere formation (transformation) through reactive oxygen species (ROS) and glycolysis shift. Transformation is linked to tumorigenesis and therapy resistance, hence targeting regulators of ROS and glycolysis is important for cancer therapeutic candidates. Here, we demonstrate that Smac mimetic AZ58in combination with tumour necrosis factor-? (TNF-?) was able to inhibit the production of ROS, inhibit glycolysis through Pim-1 kinase-mediated Ser-112 phosphorylation of BAD, and increase depolarization of mitochondria. We also identified mitochondrial isoforms of Pim-1 kinase that were targeted for degradation by AZ58in combination with TNF-? or AZ58in combination with Fas ligand (FasL) plus cycloheximide (CHX) through caspase-3 to block transformation. Our study demonstrates that Smac mimetic in combination with TNF-? is an ideal candidate to target Pim-1 expression, inhibit ROS production and to block transformation from blebbishields. PMID:26508734

  11. Production and characterization of thin film group IIIB, IVB and rare earth hydrides by reactive evaporation

    SciTech Connect

    Provo, James L.

    2015-07-15

    A recent short history of reactive evaporation by D. M. Mattox [History Corner—A Short History of Reactive Evaporation, SVC Bulletin (Society of Vacuum Coaters, Spring 2014), p. 50–51] describes various methods for producing oxides, nitrides, carbides, and some compounds, but hydrides were not mentioned. A study was performed in the mid-1970s at the General Electric Company Neutron Devices Department in Largo, FL, by the author to study preparation of thin film hydrides using reactive evaporation and to determine their unique characteristics and properties. Films were produced of scandium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), and the rare earth praseodymium (Pr), neodymium (Nd), gadolinium (Gd), dysprosium (Dy), and erbium (Er) hydrides by hot crucible filament and electron beam evaporation in atmospheres of deuterium and tritium gases. All-metal vacuum systems were used and those used with tritium were dedicated for this processing. Thin film test samples 1000 nm thick were prepared on 1.27 cm diameter molybdenum disk substrates for each occluder (i.e., an element that can react with hydrogen to form a hydride) material. Loading characteristics as determined by gas-to-metal atomic ratios, oxidation characteristics as determined by argon–sputter Auger analysis, film structure as determined by scanning electron microscope analysis, and film stress properties as determined by a double resonator technique were used to define properties of interest. Results showed hydrogen-to-metal atomic ratios varied from 1.5 to 2.0 with near maximum loading for all but Pr and Nd occluders which correlated with the oxidation levels observed, with all occluder oxidation levels being variable due to vacuum system internal processing conditions and the materials used. Surface oxide levels varied from ∼80 Å to over 1000 Å. For most films studied, results showed that a maximum loading ratio of near 2.0 and a minimum surface oxide level of ∼80 Å could be obtained with a bulk film oxygen level of ∼0.54 oxygen as determined by microprobe analysis when an evaporation rate of ∼0.313 mg/cm{sup 2} min was used in an atmosphere of D{sub 2} or T{sub 2} gas at a system deposition pressure of 1 × 10{sup −3 }Torr (1.33 × 10{sup −1 }Pa) in an evaporation time of ∼2 min. Platelet type (i.e., a film microstructure showing an overlay of flat plates with large grain sizes) film structures were observed for most films with some film mechanical properties determined (i.e., grain size and Vickers μ-hardness), and reduced stress levels were seen with initial normalized differential (tensile) stress levels being (1.0–4.0) × 10{sup 8 }dyne/cm{sup 2} for tritium loaded samples and (1.5 ± 0.5) × 10{sup 9 }dyne/cm{sup 2} for deuterium loaded samples. Also, stress aging characteristics were determined for some hydride films prepared in a radioactive tritium gas atmosphere. Tritium loading, however, had the undesirable characteristic of having to dispose of the internal processing system fixtures, which can be minimized, but the reactive evaporation technique produced desirable thin films.

  12. Reactive oxygen species production in single cells following laser irradiation (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Duquette, Michelle L.; Kim, Justine; Shi, Linda Z.; Berns, Michael W.

    2015-08-01

    Region specific DNA breaks can be created in single cells using laser light that damages DNA but does not directly generate reactive oxygen species (ROS). We have examined the cellular response to directly generated DNA breaks in single cells. Using a combination of ROS specific dyes and oxidase inhibitors we have found that the oxidase and chromatin remodeling protein Lysine demethylase I (LSD1) generates detectable ROS as a byproduct of its chromatin remodeling activity during the initial DNA damage response. ROS is produced at detectable amounts primarily within the first 3 minutes post irradiation. LSD1 activity has been previously associated with transcriptional regulation therefore these findings have implications for regulation of gene expression following DNA damage particularly in cells with altered redox states.

  13. NADPH oxidase activity and reactive oxygen species production in brain and kidney of adult male hypertensive Ren-2 transgenic rats.

    PubMed

    Vokurkov, M; Rauchov, H; ?ez?ov, L; Van??kov, I; Zicha, J

    2015-12-29

    Hypothalamic paraventricular nucleus (PVN) and rostral ventrolateral medulla (RVLM) play an important role in brain control of blood pressure (BP). One of the important mechanisms involved in the pathogenesis of hypertension is the elevation of reactive oxygen species (ROS) production by nicotine adenine dinucleotide phosphate (NADPH) oxidase. The aim of our present study was to investigate NADPH oxidase-mediated superoxide (O(2)(-)) production and to search for the signs of lipid peroxidation in hypothalamus and medulla oblongata as well as in renal medulla and cortex of hypertensive male rats transgenic for the murine Ren-2 renin gene (Ren-2 TGR) and their age-matched normotensive controls - Hannover Sprague Dawley rats (HanSD). We found no difference in the activity of NADPH oxidase measured as a lucigenin-mediated O(2)(-) production in the hypothalamus and medulla oblongata. However, we observed significantly elevated NADPH oxidase in both renal cortex and medulla of Ren-2 TGR compared with HanSD. Losartan (LOS) treatment (10 mg/kg body weight/day) for 2 months (Ren-2 TGR+LOS) did not change NADPH oxidase-dependent O(2)(-) production in the kidney. We detected significantly elevated indirect markers of lipid peroxidation measured as thiobarbituric acid-reactive substances (TBARS) in Ren-2 TGR, while they were significantly decreased in Ren-2 TGR+LOS. In conclusion, the present study shows increased NADPH oxidase activities in renal cortex and medulla with significantly increased TBARS in renal cortex. No significant changes of NADPH oxidase and markers of lipid peroxidation were detected in the studied brain regions. PMID:26713567

  14. 40 CFR Table 1 to Subpart E of... - Product-Weighted Reactivity Limits by Coating Category

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL VOLATILE ORGANIC COMPOUND EMISSION STANDARDS FOR CONSUMER AND COMMERCIAL PRODUCTS National Volatile Organic Compound Emission Standards for Aerosol...

  15. 40 CFR Table 1 to Subpart E of... - Product-Weighted Reactivity Limits by Coating Category

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL VOLATILE ORGANIC COMPOUND EMISSION STANDARDS FOR CONSUMER AND COMMERCIAL PRODUCTS National Volatile Organic Compound Emission Standards for Aerosol...

  16. Neutrino-Nucleon (Nucleus) Scattering for non-Neutrino Physics: The case of Neutral Current induced Photon Production

    NASA Astrophysics Data System (ADS)

    Zhang, Xilin

    2015-04-01

    Previously, I have studied the photon production in neutral current (NC) neutrino-nucleon (nucleus) scattering, and addressed its relevance to the MiniBooNE anomaly. (MiniBooNE is a short baseline neutrino oscillation experiment at FNAL.) In this talk I will review this topic, and discuss its connection to parity violating electron-nucleon scattering. Such electron scattering has been used in Qweak experiment at Jlab to measure precisely the proton weak charge. In addition, the nucleon-to-resonance excitations induced by both weak and electromagnetic currents play important roles in the NC photon production process. Understanding all these excitations in a unified microscopic framework is challenging. I will mention our effort along this line, and emphasize the complementarity between neutrino and electron scattering measurements of these excitations and their importance to improve our knowledge of nucleon structure. I acknowledge support from the US Department of Energy under grant DE-FG02-93ER-40756 and from Fermi National Accelerator Laboratory under Intensity Frontier Fellowship.

  17. Aluminum Toxicity Is Associated with Mitochondrial Dysfunction and the Production of Reactive Oxygen Species in Plant Cells1

    PubMed Central

    Yamamoto, Yoko; Kobayashi, Yukiko; Devi, S. Rama; Rikiishi, Sanae; Matsumoto, Hideaki

    2002-01-01

    Potential mechanisms of Al toxicity measured as Al-induced inhibition of growth in cultured tobacco cells (Nicotiana tabacum, nonchlorophyllic cell line SL) and pea (Pisum sativum) roots were investigated. Compared with the control treatment without Al, the accumulation of Al in tobacco cells caused instantaneously the repression of mitochondrial activities [monitored by the reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide and the uptake of Rhodamine 123] and, after a lag of about 12 h, triggered reactive oxygen species (ROS) production, respiration inhibition, ATP depletion, and the loss of growth capability almost simultaneously. The presence of an antioxidant, butylated hydroxyanisol, during Al treatment of SL cells prevented not only ROS production but also ATP depletion and the loss of growth capability, suggesting that the Al-triggered ROS production seems to be a cause of ATP depletion and the loss of growth capability. Furthermore, these three late events were similarly repressed in an Al-tolerant cell line (ALT301) isolated from SL cells, suggesting that the acquisition of antioxidant functions mimicking butylated hydroxyanisol can be a mechanism of Al tolerance. In the pea root, Al also triggered ROS production, respiration inhibition, and ATP depletion, which were all correlated with inhibition of root elongation. Taken together, we conclude that Al affects mitochondrial functions, which leads to ROS production, probably the key critical event in Al inhibition of cell growth. PMID:11788753

  18. Estimating production and consumption of solid reactive Fe phases in marine sediments from concentration profiles

    EPA Science Inventory

    1D diffusion models may be used to estimate rates of production and consumption of dissolved metabolites in marine sediments, but are applied less often to the solid phase. Here we used a numerical inverse method to estimate solid phase Fe(III) and Fe(II) consumption and product...

  19. Roles of reactive oxygen species in methyl jasmonate and nitric oxide-induced tanshinone production in Salvia miltiorrhiza hairy roots.

    PubMed

    Liang, Zong-Suo; Yang, Dong-Feng; Liang, Xiao; Zhang, Yue-Jin; Liu, Yan; Liu, Feng-Hua

    2012-05-01

    Salvia miltiorrhiza is one of the most popular traditional Chinese medicinal plants for treatment of coronary heart disease. Tanshinones are the main biological active compounds in S. miltiorrhiza. In this study, effects of exogenous methyl jasmonate (MJ) and nitric oxide (NO) on tanshinone production in S. miltiorrhiza hairy roots were investigated and the roles of reactive oxygen species (ROS) in MJ and NO-induced tanshinone production were elucidated further. The results showed that contents of four tanshinone compounds were significantly increased by 100 ?M MJ when compared to the control. Application of 100 ?M sodium nitroprusside (SNP), a donor of NO, also resulted in a significant increase of tanshinone production. Expression of two key genes encoding 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) and 1-deoxy-D-xylulose 5-phosphate reductoisomerase (DXR) was up-regulated by MJ and SNP. Generations of O(2)(-) and H(2)O(2) were triggered by MJ, but not by SNP. The increase of tanshinone production and up-regulation of HMGR and DXR expression induced by MJ were significantly inhibited by ROS scavengers, superoxide dismutase (SOD) and catalase (CAT). However, neither SOD nor CAT was able to suppress the SNP-induced increase of tanshinone production and expression of HMGR and DXR gene. In conclusion, tanshinone production was significantly stimulated by MJ and SNP. Of four tanshinone compounds, cryptotanshinone accumulation was most affected by MJ elicitation, while cryptotanshinone and tanshinone IIA accumulation was more affected by SNP elicitation. ROS mediated MJ-induced tanshinone production, but SNP-induced tanshinone production was ROS independent. PMID:22189441

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

    PubMed Central

    2009-01-01

    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

  1. Pentaerythritol Tetranitrate Targeting Myocardial Reactive Oxygen Species Production Improves Left Ventricular Remodeling and Function in Rats With Ischemic Heart Failure.

    PubMed

    Fraccarollo, Daniela; Galuppo, Paolo; Neuser, Jonas; Bauersachs, Johann; Widder, Julian D

    2015-11-01

    Reduced nitric oxide bioavailability contributes to progression of cardiac dysfunction and remodeling in ischemic heart failure. Clinical use of organic nitrates as nitric oxide donors is limited by development of nitrate tolerance and reactive oxygen species formation. We investigated the effects of long-term therapy with pentaerythritol tetranitrate (PETN), an organic nitrate devoid of tolerance, in rats with congestive heart failure after extensive myocardial infarction. Seven days after coronary artery ligation, rats were randomly allocated to treatment with PETN (80 mg/kg BID) or placebo for 9 weeks. Long-term PETN therapy prevented the progressive left ventricular dilatation and improved left ventricular contractile function and relaxation in rats with congestive heart failure. Mitochondrial superoxide anion production was markedly increased in the failing left ventricular myocardium and nearly normalized by PETN treatment. Gene set enrichment analysis revealed that PETN beneficially modulated the dysregulation of mitochondrial genes involved in energy metabolism, paralleled by prevention of uncoupling protein-3, thioredoxin-2, and superoxide dismutase-2 downregulation. Moreover, PETN provided a remarkable protective effect against reactive fibrosis in chronically failing hearts. Mechanistically, induction of heme oxygenase-1 by PETN prevented mitochondrial superoxide generation, NOX4 upregulation, and ensuing formation of extracellular matrix proteins in fibroblasts from failing hearts. In summary, PETN targeting reactive oxygen species generation prevented the changes of mitochondrial antioxidant enzymes and progressive fibrotic remodeling, leading to amelioration of cardiac functional performance. Therefore, PETN might be a promising therapeutic option in the treatment of ischemic heart diseases involving oxidative stress and impairment in nitric oxide bioactivity. PMID:26351025

  2. Reactive oxygen species production by blood neutrophils of patients with laryngeal carcinoma and antioxidative enzyme activity in their blood.

    PubMed

    Szuster-Ciesielska, Agnieszka; Hryciuk-Umer, Elzbieta; Stepulak, Andrzej; Kupisz, Krzysztof; Kandefer-Szerszeń, Martyna

    2004-01-01

    Squamous cell carcinoma of the head and neck is a devastating illness with a severe impact on affected individuals. Several mechanisms may lead to oxidative stress in tumor-bearing patients, among others chronic inflammation. Inflammatory cells, especially macrophages and neutrophil leukocytes, may produce reactive oxygen species (ROS) which participate in carcinogenesis and tumor-associated immunosuppression. The aim of the study presented in this paper was to compare the production of reactive oxygen species (ROS)--superoxide anion (O2-) and hydrogen peroxide (H2O2)--by neutrophils isolated from the blood of 16 patients with larynx carcinoma and 15 healthy controls. The serum activity of superoxide dismutase and catalase as well as the total peroxidase activity in serum have also been estimated. The production of ROS, especially spontaneous and phorbol 12-myristate 13-acetate (PMA)-induced O2-, was relatively higher in the patients with larynx carcinoma than in the healthy controls and increased parallel with the tumor stage (tumor, node, metastasis-TNM staging). The serum activity of catalase and peroxidase was also highest in the patients with stage T3 and T4 larynx carcinoma. After partial or total laryngectomy, a significant decrease in ROS production and the serum activity of catalase and peroxidase was observed. In contrast, the serum level of superoxide dismutase, which had been low prior to surgery, especially in the patients with advanced tumor stages (T3-T4), increased significantly afterwards. The results indicate the existence of oxidative stress in the blood of patients with larynx carcinoma and its significant decrease after partial or total laryngectomy. PMID:15244248

  3. Reactive scattering calculations for (87)Rb+(87)RbHe?Rb2((3)?(u)(+),v)+He from ultralow to intermediate energies.

    PubMed

    Rodrguez-Cantano, Roco; Gonzlez-Lezana, Toms; Prosmiti, Rita; Delgado-Barrio, Gerardo; Villarreal, Pablo; Jellinek, Julius

    2015-04-28

    We investigate atom-diatom reactive collisions, as a preliminary step,in order to assess the possibility of forming Rb(2) molecules in their lowest triplet electronic state by cold collisions of rubidium atoms on the surface of helium nanodroplets [corrected]. A simple model related to the well-known Rosen treatment of linear triatomic molecules [N. Rosen, J. Chem. Phys. 1, 319 (1933)] in relative coordinates is used, allowing to estimate reactive probabilities for different values of the total angular momentum. The best available full dimensional potential energy surface [Guillon et al., J. Chem. Phys. 136, 174307 (2012)] is employed through the calculations. Noticeable values of the probabilities in the ultracold regime, which numerically fulfill the Wigner threshold law, support the feasibility of the process. The rubidium dimer is mainly produced at high vibrational states, and the reactivity is more efficient for a bosonic helium partner than when the fermion species is considered. PMID:25933761

  4. One pion production in neutrino-nucleon scattering and the different parameterizations of the weak N?? vertex

    NASA Astrophysics Data System (ADS)

    Barbero, C.; Lpez Castro, G.; Mariano, A.

    2014-01-01

    The N?? weak vertex provides an important contribution to the one pion production in neutrino-nucleon and neutrino-nucleus scattering for ?N invariant masses below 1.4 GeV. Beyond its interest as a tool in neutrino detection and their background analyses, one pion production in neutrino-nucleon scattering is useful to test predictions based on the quark model and other internal symmetries of strong interactions. Here we try to establish a connection between two commonly used parameterizations of the weak N?? vertex and form factors (FF) and we study their effects on the determination of the axial coupling C5A(0), the common normalization of the axial FF, which is predicted to hold 1.2 by using the PCAC hypothesis. Predictions for the ??p??-p?+ total cross sections within the two approaches, which include the resonant ? and other background contributions in a coherent way, are compared to experimental data.

  5. Genotoxicity and reactive oxygen species production induced by magnetite nanoparticles in mammalian cells.

    PubMed

    Kawanishi, Masanobu; Ogo, Sayaka; Ikemoto, Miho; Totsuka, Yukari; Ishino, Kousuke; Wakabayashi, Keiji; Yagi, Takashi

    2013-01-01

    We examined the genotoxicity of magnetite nanoparticles (primary particle size: 10 nm) on human A549 and Chinese hamster ovary (CHO) AA8 cells. Six hours' treatment with the particles dose-dependently increased the frequency of micronuclei (MN) in the A549 and CHO AA8 cells up to 5.2% and 5.0% at a dose of 200 g/ml (34 g/cm), respectively. In A549 cells, treatment with the nano-particles (2 g/ml) for 1 hr induced H2AX phosphorylation, which is suggestive of DNA double strand breaks (DSB). Treating CHO AA8 cells with 2 g/ml (0.34 g/cm) magnetite for 1 hour resulted in a five times higher frequency of sister chromatid exchange (SCE) than the control level. We detected reactive oxygen species (ROS) in CHO cells treated with the particles. These findings indicate that magnetite nano-particles induce ROS in mammalian cells, leading to the direct or indirect induction of DSB, followed by clastogenic events including MN and SCE. PMID:23719928

  6. Ischemic Preconditioning Preserves Mitochondrial Membrane Potential and Limits Reactive Oxygen Species Production

    PubMed Central

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

    2012-01-01

    Background Mitochondrial superoxide radical (O2?) production increases after cardiac ischemia-reperfusion (IR). Ischemic preconditioning (IPC) preserves mitochondrial function and attenuates O2? production, but the mechanism is unknown. Mitochondrial membrane potential (m??) is known to affect O2? production; mitochondrial depolarization decreases O2? formation. We examined the relationship between O2? production and m?? during IR and IPC. Materials/Methods Rat hearts were subjected to Control or IPC. Mitochondria were isolated at end-equilibration (End EQ), end-ischemia (End I) and end-reperfusion (End RP). m?? was measured using a tetraphenylphosphonium electrode. Mitochondrial O2? production was measured by electron paramagnetic resonance (EPR) using DMPO spin trap. Cytochrome c levels were measured using high pressure liquid chromatography. Results IPC preserved m?? at End I (?1565 vs. ?1316 mV, p<0.001) and End RP (?1682 vs. ?1552 mV, p<0.05). At End RP, IPC attenuated O2? production (2527221 vs. 3523250 AU/mg protein, p<0.05). IPC preserved cytochrome c levels (35114 vs. 26916 picomoles/mg protein, p<0.05) at End RP, and decreased mitochondrial cristae disruption (104 vs. 337%, p<0.05) and amorphous density formation (184 vs. 281%, p<0.05). Conclusion We conclude that IPC preserves m??, possibly by limiting disruption of mitochondrial inner membrane. IPC also decreases mitochondrial O2? production and preserves mitochondrial ultrastructure after IR. While it was previously held that slight decreases in m?? decrease O2? production, our results indicate that preservation of m?? is associated with decreased O2? and preservation of cardiac function in IPC. These findings indicate that the mechanism of IPC may not involve m?? depolarization, but rather preservation of mitochondrial electrochemical potential. PMID:22763215

  7. Polyphenols prevent ageing-related impairment in skeletal muscle mitochondrial function through decreased reactive oxygen species production.

    PubMed

    Charles, Anne-Laure; Meyer, Alain; Dal-Ros, Stéphanie; Auger, Cyril; Keller, Nathalie; Ramamoorthy, Thanuja Gali; Zoll, Joffrey; Metzger, Daniel; Schini-Kerth, Valérie; Geny, Bernard

    2013-02-01

    Ageing is associated with skeletal muscle impairment. Changes in mitochondrial homeostasis are thought to play a key role in this process. This study examined whether chronic intake of polyphenols (PPs), which are known to be modulators of oxidative stress, might prevent the age-related decline of mitochondrial functions in skeletal muscle. Three groups of 10 Wistar rats were investigated. Rats aged 16 weeks were compared with rats aged 40 weeks that were given 75 mg kg(-1) day(-1) PPs or solvent in the drinking water starting at week 16. Mitochondrial respiratory chain complex activities were measured in saponin-skinned fibres of soleus muscles using glutamate-malate (V(max)), succinate (V(succ)) and N,N,N',N'-tetramethyl-p-phenylenediamine dihydrochloride-ascorbate (V(TMPD)). Production of reactive oxygen species was assessed using dihydroethidium staining. Transcript levels of genes involved in antioxidant defence were determined using RT-PCR. Ageing reduced muscle V(max) (from 8.8 ± 0.45 to 6.17 ± 0.51 μmol O(2) min(-1) g(-1), -30.5%, P < 0.01), V(TMPD) (from 20.67 ± 1.24 to 16.55 ± 1.16 μmol O(2) min(-1) g(-1), -19.9%, P < 0.05), increased production of reactive oxygen species (from 100 ± 9.9 to 351.1 ± 31.7%) and decreased transcripts of mitochondrial superoxide dismutase 2 (-59.3%, P < 0.01), peroxisome proliferator-activated receptor γ coactivator-1β (PGC-1β; -61.5%, P < 0.05) and sirtuin 1 (-54.2%, P < 0.05). Chronic PP intake normalized V(max) (8.63 ± 0.63 μmol O(2) min(-1) g(-1)), decreased production of reactive oxygen species (141.7 ± 16.7%, P < 0.001) and enhanced antioxidant defence (superoxide dismutase 2 expression, +151.3%, P < 0.05) and PGC-1β expression (+185.7%, P < 0.05) in comparison to age-matched untreated rats. The present data indicate that regular intake of PPs starting at a young age prevents age-related mitochondrial respiratory impairment in skeletal muscle, probably through decreased oxidative stress and enhancement of PGC-1β expression. PMID:22903980

  8. Continuous Production of Biodiesel Via an Intensified Reactive/Extractive Process

    SciTech Connect

    Tsouris, Costas; McFarlane, Joanna; Birdwell Jr, Joseph F; Jennings, Hal L

    2008-01-01

    Biodiesel is considered as a means to diversify our supply of transportation fuel, addressing the goal of reducing our dependence on oil. For a number of reasons ranging from production issues to end use, biodiesel represents only a small fraction of the transportation fuel used worldwide. This work addresses the aspect of biodiesel production that limits it to a slow batch process. Conventional production methods are batch in nature, based on the assumption that the rates of the key chemical reactions are slow. The hypothesis motivating this work is that the reaction kinetics for the transesterification of the reagent triglyceride is sufficiently fast, particularly in an excess of catalyst, and that interfacial mass transfer and phase separation control the process. If this is the case, an intensified two-phase reactor adapted from solvent extraction equipment may be utilized to greatly increase biodiesel production rates by increasing interphase transport and phase separation. To prove this idea, we are investigating two aspects: (1) determining the rate-limiting step in biodiesel production by evaluating the reaction kinetics, and (2) enhancing biodiesel production rates by using an intensified reactor. A centrifugal contactor combining interphase mass transfer, chemical reaction, and phase separation is employed for process intensification.

  9. Frequency effects on the production of reactive oxygen species in atmospheric radio frequency helium-oxygen discharges

    SciTech Connect

    Zhang, Yuantao T.; He Jin

    2013-01-15

    Several experimental and computational studies have shown that increasing frequency can effectively enhance the discharge stability in atmospheric radio-frequency (rf) discharges, but the frequency effects on the reactivity of rf discharges, represented by the densities of reactive oxygen species (ROS), are still far from fully understood. In this paper, a one-dimensional fluid model with 17 species and 65 reactions taken into account is used to explore the influences of the driving frequency on the production and destruction of ROS in atmospheric rf helium-oxygen discharges. From the computational results, with an increase in the frequency the densities of ROS decrease always at a constant power density, however, in the relatively higher frequency discharges the densities of ROS can be effectively improved by increasing the input power density with an expanded oxygen admixture range, while the discharges operate in the {alpha} mode, and the numerical data also show the optimal oxygen admixture for ground state atomic oxygen, at which the peak atomic oxygen density can be obtained, increases with the driving frequency.

  10. In situ reactive extraction of cottonseeds with methyl acetate for biodiesel production using magnetic solid acid catalysts.

    PubMed

    Wu, Haitang; Liu, Yanping; Zhang, Junhua; Li, Guanglu

    2014-12-01

    A magnetic solid acid catalyst S2O8(2)(-)/ZrO2-TiO2-Fe3O4 was prepared by coprecipitation and impregnation methods and its catalytic activity was investigated for the reactive extraction of cottonseeds with methyl acetate to produce biodiesel. The physicochemical properties of the catalyst were characterized in detail. The influences of Zr/Ti molar ratio and calcination temperature on the catalytic performance were investigated. Moreover, optimization of the reactive extraction process was performed using response surface methodology coupled with central composite design. The catalyst with a Zr/Ti molar ratio of 3/1 calcined at 550C showed the best activity. An optimum biodiesel yield of 98.5% was obtained under the reaction temperature of 50C, catalyst amount of 21.3wt.%, methyl acetate/seed ratio of 13.8ml/g and 10.8h of reaction time. Reuse of this catalyst indicated that it had steady catalytic activity and high recovery rate which could be a promising catalyst for biodiesel production from oilseeds. PMID:25463798

  11. Reactive oxygen species mediate nitric oxide production through ERK/JNK MAPK signaling in HAPI microglia after PFOS exposure.

    PubMed

    Wang, Cheng; Nie, Xiaoke; Zhang, Yan; Li, Ting; Mao, Jiamin; Liu, Xinhang; Gu, Yiyang; Shi, Jiyun; Xiao, Jing; Wan, Chunhua; Wu, Qiyun

    2015-10-15

    Perfluorooctane sulfonate (PFOS), an emerging persistent contaminant that is commonly encountered during daily life, has been shown to exert toxic effects on the central nervous system (CNS). However, the molecular mechanisms underlying the neurotoxicity of PFOS remain largely unknown. It has been widely acknowledged that the inflammatory mediators released by hyper-activated microglia play vital roles in the pathogenesis of various neurological diseases. In the present study, we examined the impact of PFOS exposure on microglial activation and the release of proinflammatory mediators, including nitric oxide (NO) and reactive oxidative species (ROS). We found that PFOS exposure led to concentration-dependent NO and ROS production by rat HAPI microglia. We also discovered that there was rapid activation of the ERK/JNK MAPK signaling pathway in the HAPI microglia following PFOS treatment. Moreover, the PFOS-induced iNOS expression and NO production were attenuated after the inhibition of ERK or JNK MAPK by their corresponding inhibitors, PD98059 and SP600125. Interestingly, NAC, a ROS inhibitor, blocked iNOS expression, NO production, and activation of ERK and JNK MAPKs, which suggested that PFOS-mediated microglial NO production occurs via a ROS/ERK/JNK MAPK signaling pathway. Finally, by exposing SH-SY5Y cells to PFOS-treated microglia-conditioned medium, we demonstrated that NO was responsible for PFOS-mediated neuronal apoptosis. PMID:26086160

  12. Reactive oxygen species production has a critical role in hypoxia-induced Stat3 activation and angiogenesis in human glioblastoma.

    PubMed

    Yu, Mi Ok; Park, Kyung-Jae; Park, Dong-Hyuk; Chung, Yong-Gu; Chi, Sung-Gil; Kang, Shin-Hyuk

    2015-10-01

    Glioblastoma is the most aggressive primary brain tumor with hypoxia-associated morphologic features including pseudopalisading necrosis and endothelial hyperplasia. It has been known that hypoxia can activate signal transducer and activator of transcription 3 (Stat3) and subsequently induce angiogenesis. However, the molecular mechanism underlying hypoxia-induced Stat3 activation has not been defined. In this study, we explored the possible implication of reactive oxygen species (ROS) in hypoxia-driven Stat3 activation in human glioblastoma. We found that hypoxic stress increased ROS production as well as Stat3 activation and that ROS inhibitors (diphenyleneiodonium, rotenone and myxothiazol) and an antioxidant (N-acetyl-L-cysteine) blocked Stat3 activation under hypoxic conditions. To determine a major route of ROS production, we tested whether nicotinamide adenine dinucleotide phosphate oxidase 4 (Nox4) is involved in hypoxia-induced ROS production. Nox4 expression was found to be increased at both mRNA and protein levels in hypoxic glioblastoma cells. In addition, siRNA-mediated knockdown of Nox4 expression abolished hypoxia induced Stat3 activation and vascular endothelial growth factor expression, which is associated with tumor cells' ability to trigger tube formation of endothelial cells in vitro. Our findings indicate that elevated ROS production plays a crucial role for Stat3 activation and angiogenesis in hypoxic glioblastoma cells. PMID:26297045

  13. NADPH Oxidase-Dependent Production of Reactive Oxygen Species Induces Endoplasmatic Reticulum Stress in Neutrophil-Like HL60 Cells

    PubMed Central

    Kuwabara, Wilson Mitsuo Tatagiba; Zhang, Liling; Schuiki, Irmgard; Curi, Rui; Volchuk, Allen; Alba-Loureiro, Tatiana Carolina

    2015-01-01

    Reactive oxygen species (ROS) primarily produced via NADPH oxidase play an important role for killing microorganisms in neutrophils. In this study we examined if ROS production in Human promyelocytic leukemia cells (HL60) differentiated into neutrophil-like cells (dHL60) induces ER stress and activates the unfolded protein response (UPR). To cause ROS production cells were treated with PMA or by chronic hyperglycemia. Chronic hyperglycemia failed to induce ROS production and did not cause activation of the UPR in dHL60 cells. PMA, a pharmacologic NADPH oxidase activator, induced ER stress in dHL60 cells as monitored by IRE-1 and PERK pathway activation, and this was independent of calcium signaling. The NADPH oxidase inhibitor, DPI, abolished both ROS production and UPR activation. These results show that ROS produced by NADPH oxidase induces ER stress and suggests a close association between the redox state of the cell and the activation of the UPR in neutrophil-like HL60 cells. PMID:25668518

  14. Reactive processing of formaldehyde and acetaldehyde in aqueous aerosol mimics: surface tension depression and secondary organic products

    NASA Astrophysics Data System (ADS)

    Li, Z.; Schwier, A. N.; Sareen, N.; McNeill, V. F.

    2011-07-01

    The reactive uptake of carbonyl-containing volatile organic compounds (cVOCs) by aqueous atmospheric aerosols is a likely source of particulate organic material. The aqueous-phase secondary organic products of some cVOCs are surface-active. Therefore, cVOC uptake can lead to organic film formation at the gas-aerosol interface and changes in aerosol surface tension. We examined the chemical reactions of two abundant cVOCs, formaldehyde and acetaldehyde, in water and aqueous ammonium sulfate (AS) solutions mimicking tropospheric aerosols. Secondary organic products were identified using Aerosol Chemical Ionization Mass Spectrometry (Aerosol-CIMS), and changes in surface tension were monitored using pendant drop tensiometry. Hemiacetal oligomers and aldol condensation products were identified using Aerosol-CIMS. A hemiacetal sulfate ester was tentatively identified in the formaldehyde-AS system. Acetaldehyde depresses surface tension to 65(2) dyn cm-1 in pure water and 62(1) dyn cm-1 in AS solutions. Surface tension depression by formaldehyde in pure water is negligible; in AS solutions, a 9 % reduction in surface tension is observed. Mixtures of these species were also studied in combination with methylglyoxal in order to evaluate the influence of cross-reactions on surface tension depression and product formation in these systems. We find that surface tension depression in the solutions containing mixed cVOCs exceeds that predicted by an additive model based on the single-species isotherms.

  15. Reactive processing of formaldehyde and acetaldehyde in aqueous aerosol mimics: surface tension depression and secondary organic products

    NASA Astrophysics Data System (ADS)

    Li, Z.; Schwier, A. N.; Sareen, N.; McNeill, V. F.

    2011-11-01

    The reactive uptake of carbonyl-containing volatile organic compounds (cVOCs) by aqueous atmospheric aerosols is a likely source of particulate organic material. The aqueous-phase secondary organic products of some cVOCs are surface-active. Therefore, cVOC uptake can lead to organic film formation at the gas-aerosol interface and changes in aerosol surface tension. We examined the chemical reactions of two abundant cVOCs, formaldehyde and acetaldehyde, in water and aqueous ammonium sulfate (AS) solutions mimicking tropospheric aerosols. Secondary organic products were identified using Aerosol Chemical Ionization Mass Spectrometry (Aerosol-CIMS), and changes in surface tension were monitored using pendant drop tensiometry. Hemiacetal oligomers and aldol condensation products were identified using Aerosol-CIMS. Acetaldehyde depresses surface tension to 65(2) dyn cm-1 in pure water (a 10% surface tension reduction from that of pure water) and 62(1) dyn cm-1 in AS solutions (a 20.6% reduction from that of a 3.1 M AS solution). Surface tension depression by formaldehyde in pure water is negligible; in AS solutions, a 9% reduction in surface tension is observed. Mixtures of these species were also studied in combination with methylglyoxal in order to evaluate the influence of cross-reactions on surface tension depression and product formation in these systems. We find that surface tension depression in the solutions containing mixed cVOCs exceeds that predicted by an additive model based on the single-species isotherms.

  16. Arylhydrocarbon receptor (AhR) activation in airway epithelial cells induces MUC5AC via reactive oxygen species (ROS) production.

    PubMed

    Chiba, Takahito; Uchi, Hiroshi; Tsuji, Gaku; Gondo, Hisaki; Moroi, Yoichi; Furue, Masutaka

    2011-02-01

    The dioxins and dioxin-like compounds in cigarette smoke regulate various immunological responses via the arylhydrocarbon receptor (AhR). These environmental toxicants are known to cause bronchitis, asthma, chronic obstructive pulmonary disease (COPD), and lung cancer. Recent studies have demonstrated that AhR activation upregulates the expression of mucin 5AC, oligomeric mucus/gel-forming (MUC5AC) in the airway epithelial cell line. However, the mechanism for the production of mucin has not been clarified. In this study, we investigated the role and pathway of AhR in airway epithelial cells by using selective agonists and antagonists. After stimulation with or without benzopyrene (B[a]P), an AhR agonist, MUC5AC expression was measured by real-time RT-PCR. The mechanism of AhR-induced MUC5AC expression in airway epithelial cells was studied in terms of the production of cytokine and reactive oxygen species (ROS). Treatment with B[a]P increased ROS generation in NCI-H₂₉₂ cells. Furthermore, B[a]P-induced MUC5AC upregulation and mucin production were inhibited by AhR siRNA or the use of an antioxidative agent. These results suggest that the AhR-induced increase of mucin production is partially mediated by ROS generation. An antioxidant therapy approach may help to cure AhR-induced mucus hypersecretory diseases. PMID:20709182

  17. Distribution of Linearly Polarized Gluons and Elliptic Azimuthal Anisotropy in Deep Inelastic Scattering Dijet Production at High Energy.

    PubMed

    Dumitru, Adrian; Lappi, Tuomas; Skokov, Vladimir

    2015-12-18

    We determine the distribution of linearly polarized gluons of a dense target at small x by solving the Balitsky-Jalilian-Marian-Iancu-McLerran-Weigert-Leonidov-Kovner rapidity evolution equations. From these solutions, we estimate the amplitude of ?cos2? azimuthal asymmetries in deep inelastic scattering dijet production at high energies. We find sizable long-range in rapidity azimuthal asymmetries with a magnitude in the range of v_{2}=?cos2???10%. PMID:26722917

  18. Distribution of Linearly Polarized Gluons and Elliptic Azimuthal Anisotropy in Deep Inelastic Scattering Dijet Production at High Energy

    NASA Astrophysics Data System (ADS)

    Dumitru, Adrian; Lappi, Tuomas; Skokov, Vladimir

    2015-12-01

    We determine the distribution of linearly polarized gluons of a dense target at small x by solving the Balitsky-Jalilian-Marian-Iancu-McLerran-Weigert-Leonidov-Kovner rapidity evolution equations. From these solutions, we estimate the amplitude of cos 2 ? azimuthal asymmetries in deep inelastic scattering dijet production at high energies. We find sizable long-range in rapidity azimuthal asymmetries with a magnitude in the range of v2=?cos 2 ? ?10 % .

  19. Gamma ray production cross-sections associated with multiple inelastic scattering of 14 MeV neutrons in lead

    NASA Astrophysics Data System (ADS)

    Warner, P. C.; Cox, A. J.

    1985-11-01

    The gamma ray angular distributions and differential production cross-sections have been measured for the inelastic scattering of 14 MeV neutrons in lead, using a gamma ray spectrometer based on an associated particle time-of-flight gating technique. The variation of cross-section with sample thickness was measured and the results compared with the predictions of the Monte Carlo computer code MORSE.

  20. Reactive oxygen species production by potato tuber mitochondria is modulated by mitochondrially bound hexokinase activity.

    PubMed

    Camacho-Pereira, Juliana; Meyer, Laudiene Evangelista; Machado, Lilia Bender; Oliveira, Marcus Fernandes; Galina, Antonio

    2009-02-01

    Potato tuber (Solanum tuberosum) mitochondria (PTM) have a mitochondrially bound hexokinase (HK) activity that exhibits a pronounced sensitivity to ADP inhibition. Here we investigated the role of mitochondrial HK activity in PTM reactive oxygen species generation. Mitochondrial HK has a 10-fold higher affinity for glucose (Glc) than for fructose (KMGlc=140 microM versus KMFrc=1,375 microM). Activation of PTM respiration by succinate led to an increase in hydrogen peroxide (H2O2) release that was abrogated by mitochondrial HK activation. Mitochondrial HK activity caused a decrease in the mitochondrial membrane potential and an increase in oxygen consumption by PTM. Inhibition of Glc phosphorylation by mannoheptulose or GlcNAc induced a rapid increase in H2O2 release. The blockage of H2O2 release sustained by Glc was reverted by oligomycin and atractyloside, indicating that ADP recycles through the adenine nucleotide translocator and F0F1ATP synthase is operative during the mitochondrial HK reaction. Inhibition of mitochondrial HK activity by 60% to 70% caused an increase of 50% in the maximal rate of H2O2 release. Inhibition in H2O2 release by mitochondrial HK activity was comparable to, or even more potent, than that observed for StUCP (S. tuberosum uncoupling protein) activity. The inhibition of H2O2 release in PTM was two orders of magnitude more selective for the ADP produced from the mitochondrial HK reaction than for that derived from soluble yeast (Saccharomyces cerevisiae) HK. Modulation of H2O2 release and oxygen consumption by Glc and mitochondrial HK inhibitors in potato tuber slices shows that hexoses and mitochondrial HK may act as a potent preventive antioxidant mechanism in potato tubers. PMID:19109413

  1. ?-Cell Uncoupling Protein 2 Regulates Reactive Oxygen Species Production, Which Influences Both Insulin and Glucagon Secretion

    PubMed Central

    Robson-Doucette, Christine A.; Sultan, Sobia; Allister, Emma M.; Wikstrom, Jakob D.; Koshkin, Vasilij; Bhatacharjee, Alpana; Prentice, Kacey J.; Sereda, Samuel B.; Shirihai, Orian S.; Wheeler, Michael B.

    2011-01-01

    OBJECTIVE The role of uncoupling protein 2 (UCP2) in pancreatic ?-cells is highly debated, partly because of the broad tissue distribution of UCP2 and thus limitations of whole-body UCP2 knockout mouse models. To investigate the function of UCP2 in the ?-cell, ?-cellspecific UCP2 knockout mice (UCP2BKO) were generated and characterized. RESEARCH DESIGN AND METHODS UCP2BKO mice were generated by crossing loxUCP2 mice with mice expressing rat insulin promoter-driven Cre recombinase. Several in vitro and in vivo parameters were measured, including respiration rate, mitochondrial membrane potential, islet ATP content, reactive oxygen species (ROS) levels, glucose-stimulated insulin secretion (GSIS), glucagon secretion, glucose and insulin tolerance, and plasma hormone levels. RESULTS UCP2BKO ?-cells displayed mildly increased glucose-induced mitochondrial membrane hyperpolarization but unchanged rates of uncoupled respiration and islet ATP content. UCP2BKO islets had elevated intracellular ROS levels that associated with enhanced GSIS. Surprisingly, UCP2BKO mice were glucose-intolerant, showing greater ?-cell area, higher islet glucagon content, and aberrant ROS-dependent glucagon secretion under high glucose conditions. CONCLUSIONS Using a novel ?-cellspecific UCP2KO mouse model, we have shed light on UCP2 function in primary ?-cells. UCP2 does not behave as a classical metabolic uncoupler in the ?-cell, but has a more prominent role in the regulation of intracellular ROS levels that contribute to GSIS amplification. In addition, ?-cell UCP2 contributes to the regulation of intraislet ROS signals that mediate changes in ?-cell morphology and glucagon secretion. PMID:21984579

  2. Subclass-specific labeling of protein-reactive natural products with customized nucleophilic probes.

    PubMed

    Rudolf, Georg C; Koch, Maximilian F; Mandl, Franziska A M; Sieber, Stephan A

    2015-02-23

    Natural products represent a rich source of bioactive compounds that constitute a large fraction of approved drugs. Among those are molecules with electrophilic scaffolds, such as Michael acceptors, ?-lactams, and epoxides that irreversibly inhibit essential enzymes based on their catalytic mechanism. In the search for novel bioactive molecules, current methods are challenged by the frequent rediscovery of known chemical entities. Herein small nucleophilic probes that attack electrophilic natural products and enhance their detection by HPLC-UV and HPLC-MS are introduced. A screen of diverse probe designs revealed one compound with a desired selectivity for epoxide- and maleimide-based antibiotics. Correspondingly, the natural products showdomycin and phosphomycin could be selectively targeted in extracts of their natural producing organism, in which the probe-modified molecules exhibited superior retention and MS detection relative to their unmodified counterparts. This method may thus help to discover small, electrophilic molecules that might otherwise easily elude detection in complex samples. PMID:25605563

  3. Defining the mechanisms by which the reactive oxygen species by-product, 4-hydroxynonenal, affects human sperm cell function.

    PubMed

    Baker, Mark A; Weinberg, Anita; Hetherington, Louise; Villaverde, Ana-Izabel; Velkov, Tony; Baell, Jonathan; Gordon, Christopher P

    2015-04-01

    Lipid peroxidation products such as the naturally occurring aldehyde 4-hydroxynonenal (4-HNE) are known to be cytotoxic toward different cell types, including spermatozoa. In order to understand this at the molecular level, we have employed a proteomic approach to characterize direct 4-HNE adducts on human spermatozoa. Several proteins were identified to be of particular interest, including aldehyde labeling of histone methyltransferase and dynein heavy chain. In addition, we found that 4-HNE bound to part of the activation segment, cysteine residue 199, of protein kinase A (PKA). Interestingly, at low levels, addition of 4-HNE had a stimulatory effect on PKA. However, this did not correlate to increased phosphotyrosine levels during capacitation. This data explains the link between reactive oxygen species and sperm toxicity. Given that epigenetic regulation is likely affected in oxidative-stressed spermatozoa, this data show that spermatozoa appear to shut down under these conditions before reaching the egg. PMID:25673561

  4. Comparison of the chemical reactivity of synthetic peroxynitrite with that of the autoxidation products of nitroxyl or its anion.

    PubMed

    Jorolan, Joel H; Buttitta, Lisa Ann; Cheah, Cheryl; Miranda, Katrina M

    2015-01-30

    Donors of nitroxyl (HNO) exhibit pharmacological properties that are potentially favorable for treatment of a variety of diseases. To fully evaluate the pharmacological utility of HNO, it is therefore important to understand its chemistry, particularly involvement in deleterious biological reactions. Of particular note is the cytotoxic species formed from HNO autoxidation that is capable of inducing double strand DNA breaks. The identity of this species remains elusive, but a conceivable product is peroxynitrous acid. However, chemical comparison studies have demonstrated that HNO autoxidation leads to a unique reactive nitrogen oxide species to that of synthetic peroxynitrite. Here, we extend the analysis to include a new preparation of peroxynitrite formed via autoxidation of nitroxyl anion (NO(-)). Both peroxynitrite preparations exhibited similar chemical profiles, although autoxidation of NO(-) provided a more reliable sample of peroxynitrite. Furthermore, the observed dissimilarities to the HNO donor Angeli's salt substantiate that HNO autoxidation produces a unique intermediate from peroxynitrite. PMID:25460322

  5. Effects of endogenous neurotoxin quinolinic acid on reactive oxygen species production by Fenton reaction catalyzed by iron or copper

    PubMed Central

    Kubicova, Lenka; Hadacek, Franz; Weckwerth, Wolfram; Chobot, Vladimir

    2015-01-01

    The tryptophan metabolite, quinolinic (2,3-pyridinedicarboxylic) acid, is known as an endogenous neurotoxin. Quinolinic acid can form coordination complexes with iron or copper. The effects of quinolinic acid on reactive oxygen species production in the presence of iron or copper were explored by a combination of chemical assays, classical site-specific and ascorbic acid-free variants of the deoxyribose degradation assay, and mass spectrometry (ESI–MS). Quinolinic acid showed evident antioxidant activity in chemical assays, but the effect was more pronounced in the presence of copper as transition metal catalyst than in presence of iron. Nano-ESI–MS confirmed the ability of quinolinic acid to form coordination complexes with iron(II) or copper(II) and quinolinic acid stability against oxidative attack by hydroxyl radicals. The results illustrate a highly milieu-dependent quinolinic acid chemistry when it enters reactions as competitive ligand. PMID:25892824

  6. Hypoxia dysregulates the production of adiponectin and plasminogen activator inhibitor-1 independent of reactive oxygen species in adipocytes

    SciTech Connect

    Chen Baoying; Lam, Karen S.L.; Wang Yu; Wu Donghai; Lam, Michael C.; Shen Jiangang; Wong Laiching; Hoo, Ruby L.C.; Zhang Jialiang; Xu Aimin . E-mail: amxu@hkucc.hku.hk

    2006-03-10

    Low plasma levels of adiponectin (hypoadiponectinemia) and elevated circulating concentrations of plasminogen activator inhibitor (PAI)-1 are causally associated with obesity-related insulin resistance and cardiovascular disease. However, the mechanism that mediates the aberrant production of these two adipokines in obesity remains poorly understood. In this study, we investigated the effects of hypoxia and reactive oxygen species (ROS) on production of adiponectin and PAI-1 in 3T3-L1 adipocytes. Quantitative PCR and immunoassays showed that ambient hypoxia markedly suppressed adiponectin mRNA expression and its protein secretion, and increased PAI-1 production in mature adipocytes. Dimethyloxallyl glycine, a stabilizer of hypoxia-inducible factor 1{alpha} (HIF-1{alpha}), mimicked the hypoxia-mediated modulations of these two adipokines. Hypoxia caused a modest elevation of ROS in adipocytes. However, ablation of intracellular ROS by antioxidants failed to alleviate hypoxia-induced aberrant production of adiponectin and PAI-1. On the other hand, the antioxidants could reverse hydrogen peroxide (H{sub 2}O{sub 2})-induced dysregulation of adiponectin and PAI-1 production. H{sub 2}O{sub 2} treatment decreased the expression levels of peroxisome proliferator-activated receptor gamma (PPAR{gamma}) and CCAAT/enhancer binding protein (C/EBP{alpha}), but had no effect on HIF-1{alpha}, whereas hypoxia stabilized HIF-1{alpha} and decreased expression of C/EBP{alpha}, but not PPAR{gamma}. Taken together, these data suggest that hypoxia and ROS decrease adiponectin production and augment PAI-1 expression in adipocytes via distinct signaling pathways. These effects may contribute to hypoadiponectinemia and elevated PAI-1 levels in obesity, type 2 diabetes, and cardiovascular diseases.

  7. Photosensitized Production of Atmospherically Reactive Organic Compounds at the Air/Aqueous Interface.

    PubMed

    Fu, Hongbo; Ciuraru, Raluca; Dupart, Yoan; Passananti, Monica; Tinel, Liselotte; Rossignol, Stphanie; Perrier, Sebastien; Donaldson, D James; Chen, Jianmin; George, Christian

    2015-07-01

    We report on experiments that probe photosensitized chemistry at the air/water interface, a region that does not just connect the two phases but displays its own specific chemistry. Here, we follow reactions of octanol, a proxy for environmentally relevant soluble surfactants, initiated by an attack by triplet-state carbonyl compounds, which are themselves concentrated at the interface by the presence of this surfactant. Gas-phase products are determined using PTR-ToF-MS, and those remaining in the organic layer are determined by ATR-FTIR spectroscopy and HPLC-HRMS. We observe the photosensitized production of carboxylic acids as well as unsaturated and branched-chain oxygenated products, compounds that act as organic aerosol precursors and had been thought to be produced solely by biological activity. A mechanism that is consistent with the observations is detailed here, and the energetics of several key reactions are calculated using quantum chemical methods. The results suggest that the concentrating nature of the interface leads to its being a favorable venue for radical reactions yielding complex and functionalized products that themselves could initiate further secondary chemistry and new particle formation in the atmospheric environment. PMID:26068588

  8. 40 CFR Table 1 to Subpart E of... - Product-Weighted Reactivity Limits by Coating Category

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Primers ABP 1.55 Automotive Bumper and Trim Products ABT 1.75 Aviation or Marine Primers AMP 2.00 Aviation... Finish—Engine Enamel EEE 1.70 Exact Match Finish—Automotive EFA 1.50 Exact Match Finish—Industrial EFI...

  9. ORGANIC MATTER REACTIVITY SURROGATE FOR THE ESTIMATION OF DISINFECTION BY-PRODUCTS FORMATION POTENTIAL

    EPA Science Inventory

    The EPA Office of Ground Water and Drinking Water must have a total organic carbon (TOC) method that can meet the monitoring requirements as originally proposed in the Stage 1, Disinfection By-Products (D/DBP) Rule, as stated in the Federal Register. Research under this task, th...

  10. Photosensitized Production of Atmospherically Reactive Organic Compounds at the Air/Aqueous Interface

    PubMed Central

    2015-01-01

    We report on experiments that probe photosensitized chemistry at the air/water interface, a region that does not just connect the two phases but displays its own specific chemistry. Here, we follow reactions of octanol, a proxy for environmentally relevant soluble surfactants, initiated by an attack by triplet-state carbonyl compounds, which are themselves concentrated at the interface by the presence of this surfactant. Gas-phase products are determined using PTR-ToF-MS, and those remaining in the organic layer are determined by ATR-FTIR spectroscopy and HPLC-HRMS. We observe the photosensitized production of carboxylic acids as well as unsaturated and branched-chain oxygenated products, compounds that act as organic aerosol precursors and had been thought to be produced solely by biological activity. A mechanism that is consistent with the observations is detailed here, and the energetics of several key reactions are calculated using quantum chemical methods. The results suggest that the concentrating nature of the interface leads to its being a favorable venue for radical reactions yielding complex and functionalized products that themselves could initiate further secondary chemistry and new particle formation in the atmospheric environment. PMID:26068588

  11. Spacecraft self-contamination due to back-scattering of outgas products

    NASA Technical Reports Server (NTRS)

    Robertson, S. J.

    1976-01-01

    The back-scattering of outgas contamination near an orbiting spacecraft due to intermolecular collisions was analyzed. Analytical tools were developed for making reasonably accurate quantitative estimates of the outgas contamination return flux, given a knowledge of the pertinent spacecraft and orbit conditions. Two basic collision mechanisms were considered: (1) collisions involving only outgas molecules (self-scattering) and (2) collisions between outgas molecules and molecules in the ambient atmosphere (ambient-scattering). For simplicity, the geometry was idealized to a uniformly outgassing sphere and to a disk oriented normal to the freestream. The method of solution involved an integration of an approximation of the Boltzmann kinetic equation known as the BGK (or Krook) model equation. Results were obtained in the form of simple equations relating outgas return flux to spacecraft and orbit parameters. Results were compared with previous analyses based on more simplistic models of the collision processes.

  12. Spatial Coordination of Aluminum Uptake, Production of Reactive Oxygen Species, Callose Production and Wall Rigidification in Maize Roots

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aluminum toxicity associated with acid soils represents one of the biggest limitations to crop production worldwide. Although Al specifically inhibits the elongation of root cells, the exact mechanism by which this growth reduction occurs remains controversial. The aim of this study was to investiga...

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

    PubMed

    Lim, Steven; Lee, Keat Teong

    2013-08-01

    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, 300C, 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

  14. Sanguinarine-induced apoptosis in lung adenocarcinoma cells is dependent on reactive oxygen species production and endoplasmic reticulum stress.

    PubMed

    Gu, Shuang; Yang, Xiao-Chun; Xiang, Xi-Yan; Wu, Yao; Zhang, Yu; Yan, Xiao-Yu; Xue, Ya-Nan; Sun, Lian-Kun; Shao, Guo-Guang

    2015-08-01

    Sanguinarine (SAN), an alkaloid isolated from plants of the Papaveraceae family, is a compound with multiple biological activities. In the present study, we explored the anticancer properties of SAN in lung cancer using the human lung adenocarcinoma cell line SPC-A1. Our results revealed that SAN inhibited SPC-A1 cell growth and induced apoptosis in a dose-dependent manner. We found that SAN triggered reactive oxygen species (ROS) production, while elimination of ROS by N-acetylcysteine (NAC) reversed the growth inhibition and apoptosis induced by SAN. SAN-induced endoplasmic reticulum (ER) stress resulted in the upregulation of many genes and proteins involved in the unfolded protein response (UPR) pathway, including glucose-regulated protein 78 (GRP78), p-protein kinase R (PKR)-like ER kinase (PERK), p-eukaryotic translation initiation factor 2? (eIF2?), activating transcription factor 4 (ATF4) and CCAAT/enhancer binding protein homologous protein (CHOP). Blocking ER stress with tauroursodeoxycholic acid (TUDCA) markedly reduced SAN-induced inhibition of growth and apoptosis. Furthermore, TUDCA decreased SAN-induced ROS production, and NAC attenuated SAN-induced GRP78 and CHOP expression. Overall, our data indicate that the anticancer effects of SAN in lung cancer cells depend on ROS production and ER stress and that SAN may be a potential agent against lung cancer. PMID:26081590

  15. Galangin prevents aminoglycoside-induced ototoxicity by decreasing mitochondrial production of reactive oxygen species in mouse cochlear cultures.

    PubMed

    Kim, Ye-Ri; Kim, Min-A; Cho, Hyun-Ju; Oh, Se-Kyung; Lee, In-Kyu; Kim, Un-Kyung; Lee, Kyu-Yup

    2016-03-14

    Amikacin is a semi-synthetic aminoglycoside widely used to treat infections caused by gentamicin-resistant gram-negative organisms and nontuberculous mycobacteria. However, the use of this agent often results in ototoxicity due to the overproduction of reactive oxygen species (ROS). Galangin, a natural flavonoid, has been shown to play a protective role against mitochondrial dysfunction by reducing mitochondrial ROS production. In this study, the effect of galangin on amikacin-induced ototoxicity was examined using cultures of cochlear explants. Immunofluorescent staining showed that treatment of inner hair cells (IHCs) and outer hair cells (OHCs) with galangin significantly decreased damage induced by amikacin. Moreover, pretreatment with galangin resulted in decreased amikacin-provoked increase in ROS production in both types of hair cells by MitoSOX-red staining. Attenuation of apoptotic cell death was assessed immunohistochemically using active caspase-3 antibody and with terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, compared to explants exposed to amikacin alone (P<0.05). These results indicate that galangin protects hair cells in the organ of Corti from amikacin-induced toxicity by reducing the production of mitochondrial ROS. The results of this study suggest that galangin can potentially be used as an antioxidant and antiapoptotic agent to prevent hearing loss caused by aminoglycoside induced-oxidative stress. PMID:26778349

  16. Effects of shear stresses and antioxidant concentrations on the production of reactive oxygen species in lung cancer cells

    PubMed Central

    Lo, Kai-Yin; Zhu, Yun; Tsai, Hsieh-Fu; Sun, Yung-Shin

    2013-01-01

    Reactive oxygen species (ROS) are known to be a key factor in the development of cancer, and many exogenous sources are supposed to be related to the formation of ROS. In this paper, a microfluidic chip was developed for studying the production of ROS in lung cancer cells under different chemical and physical stimuli. This chip has two unique features: (1) five relative concentrations of 0, 1/8, 1/2, 7/8, and 1 are achieved in the culture regions; (2) a shear stress gradient is produced inside each of the five culture areas. Lung cancer cells were seeded inside this biocompatible chip for investigating their response to different concentrations of H2O2, a chemical stimulus known to increase the production of ROS. Then the effect of shear stress, a physical stimulus, on lung cancer cells was examined, showing that the production of ROS was increased in response to a larger shear stress. Finally, two antioxidants, ?-tocopherol and ferulic acid, were used to study their effects on reducing ROS. It was found that high-dose ?-tocopherol was not able to effectively eliminate the ROS produced inside cells. This counter effect was not observed in cells cultured in a traditional chamber slide, where no shear stress was present. This result suggests that the current microfluidic chip provides an in vitro platform best mimicking the physiological condition where cells are under circulating conditions. PMID:24396542

  17. Entropy and chemical change. 1: Characterization of product (and reactant) energy distributions in reactive molecular collisions: Information and enthropy deficiency

    NASA Technical Reports Server (NTRS)

    Bernstein, R. B.; Levine, R. D.

    1972-01-01

    Optimal means of characterizing the distribution of product energy states resulting from reactive collisions of molecules with restricted distributions of initial states are considered, along with those for characterizing the particular reactant state distribution which yields a given set of product states at a specified total energy. It is suggested to represent the energy-dependence of global-type results in the form of square-faced bar plots, and of data for specific-type experiments as triangular-faced prismatic plots. The essential parameters defining the internal state distribution are isolated, and the information content of such a distribution is put on a quantitative basis. The relationship between the information content, the surprisal, and the entropy of the continuous distribution is established. The concept of an entropy deficiency, which characterizes the specificity of product state formation, is suggested as a useful measure of the deviance from statistical behavior. The degradation of information by experimental averaging is considered, leading to bounds on the entropy deficiency.

  18. 40 CFR Table 1 to Subpart E of... - Product-Weighted Reactivity Limits by Coating Category

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... FCP 1.20 Fluorescent Coatings FLP 1.75 Metallic Coatings MCP 1.90 Non-Flat Coatings NFP 1.40 Primers PCP 1.20 Ground Traffic/Marking GTM 1.20 Art Fixatives or Sealants AFS 1.80 Auto body primers ABP 1.55 Automotive Bumper and Trim Products ABT 1.75 Aviation or Marine Primers AMP 2.00 Aviation Propellor...

  19. 40 CFR Table 1 to Subpart E of... - Product-Weighted Reactivity Limits by Coating Category

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... FCP 1.20 Fluorescent Coatings FLP 1.75 Metallic Coatings MCP 1.90 Non-Flat Coatings NFP 1.40 Primers PCP 1.20 Ground Traffic/Marking GTM 1.20 Art Fixatives or Sealants AFS 1.80 Auto body primers ABP 1.55 Automotive Bumper and Trim Products ABT 1.75 Aviation or Marine Primers AMP 2.00 Aviation Propellor...

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

    PubMed

    Lang, Annie; Lee, Sungkyoung

    2014-09-01

    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

  1. Comparison of ecdysteroid production in Drosophila and Manduca: pharmacology and cross-species neural reactivity.

    PubMed

    Henrich, V C

    1995-01-01

    In both Manduca sexta and Drosophila melanogaster, metamorphic events are driven by ecdysteroids whose production in prothoracic gland (PGs) is stimulated periodically by neural factors. Differences in the life cycle of moths and flies have made it difficult to compare the regulation of ecdysteroid biosynthesis in these two species. As in Manduca, at least two neural factors in the larval Drosophila BVG complex were separable by molecular weight, and they stimulated increased ecdysteroid biosynthesis from the ring gland, a composite organ that includes PG cells. Drosophila neural extracts accelerated ecdysteroid biosynthesis in Manduca PGs and, conversely, partially purified Manduca PTTH preparations elevated ecdysteroid biosynthesis in Drosophila ring glands, suggesting that the two species may share structurally similar prothoracicotropic factors. Drosophila ring glands required the presence of calcium ions to respond to neural extracts, but the phosphodiesterase inhibitor MIX and cAMP analogues exerted little, if any, positive effect on production. Mean ecdysteroid production rates of BVG-ring gland complexes taken from Drosophila larvae during various phases of the wandering period were often submaximal and highly variable, suggesting that they fluctuate widely prior to pupariation. Based on available data in Drosophila and the Manduca model for the control of ecdysteroid biosynthesis, a developmental scheme for neuroendocrine control in Drosophila is proposed. PMID:7579574

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

    PubMed

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

    2014-08-19

    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

  3. Regulation of cytokine-induced human C-reactive protein production by transforming growth factor-beta.

    PubMed

    Taylor, A W; Ku, N O; Mortensen, R F

    1990-10-15

    Transforming growth factor-beta (TGF-beta) modified production of the major human acute phase reactant, C-reactive protein (CRP), induced by the inflammatory cytokines, IL-1 beta or IL-6. CRP mRNA accumulation in the hepatoma PLC/PRF/5 cell line was slightly more rapid, but of smaller magnitude in response to IL-1 beta (fourfold increase) than to IL-6 (10-fold increase); however, the amount of CRP protein accumulating in the culture medium was similar for both cytokines. TGF-beta at concentrations greater than or equal to 0.1 pg/ml inhibited the induced IL-1 or IL-6 CRP production; whereas concentrations less than 0.1 pg/ml slightly enhanced CRP synthesis. Addition of TGF-beta to the cultures up to 16 h after the PLC/PRF/5 cells were already exposed to IL-1 or IL-6 resulted in the cessation of CRP production. CRP mRNA accumulated in hepatoma cells treated with both TGF-beta and IL-6, although CRP protein synthesis was inhibited. A similar pattern of inhibition of CRP production by TGF-beta occurred when Hep 3B.2 cells were treated with a mixture of IL-1 and IL-6. Enhanced production of CRP was observed only when TGF-beta was added to the cells before the cytokine. This enhanced CRP response was sensitive to cycloheximide. TGF-beta added along with IL-6 inhibited the metabolic labeling of CRP with [35S]methionine; however, enhanced incorporation of [35S]methionine into CRP was observed when the cells were exposed to TGF-beta before IL-6 addition. Therefore, TGF-beta is potentially a potent regulator of CRP synthesis by hepatocytes at the post-transcriptional level. PMID:2170518

  4. Reactive Oxygen Species-Dependent Nitric Oxide Production Contributes to Hydrogen-Promoted Stomatal Closure in Arabidopsis1[W

    PubMed Central

    Xie, Yanjie; Mao, Yu; Zhang, Wei; Lai, Diwen; Wang, Qingya; Shen, Wenbiao

    2014-01-01

    The signaling role of hydrogen gas (H2) has attracted increasing attention from animals to plants. However, the physiological significance and molecular mechanism of H2 in drought tolerance are still largely unexplored. In this article, we report that abscisic acid (ABA) induced stomatal closure in Arabidopsis (Arabidopsis thaliana) by triggering intracellular signaling events involving H2, reactive oxygen species (ROS), nitric oxide (NO), and the guard cell outward-rectifying K+ channel (GORK). ABA elicited a rapid and sustained H2 release and production in Arabidopsis. Exogenous hydrogen-rich water (HRW) effectively led to an increase of intracellular H2 production, a reduction in the stomatal aperture, and enhanced drought tolerance. Subsequent results revealed that HRW stimulated significant inductions of NO and ROS synthesis associated with stomatal closure in the wild type, which were individually abolished in the nitric reductase mutant nitrate reductase1/2 (nia1/2) or the NADPH oxidase-deficient mutant rbohF (for respiratory burst oxidase homolog). Furthermore, we demonstrate that the HRW-promoted NO generation is dependent on ROS production. The rbohF mutant had impaired NO synthesis and stomatal closure in response to HRW, while these changes were rescued by exogenous application of NO. In addition, both HRW and hydrogen peroxide failed to induce NO production or stomatal closure in the nia1/2 mutant, while HRW-promoted ROS accumulation was not impaired. In the GORK-null mutant, stomatal closure induced by ABA, HRW, NO, or hydrogen peroxide was partially suppressed. Together, these results define a main branch of H2-regulated stomatal movement involved in the ABA signaling cascade in which RbohF-dependent ROS and nitric reductase-associated NO production, and subsequent GORK activation, were causally involved. PMID:24733882

  5. Reactive Oxygen Species-Dependent Nitric Oxide Production Contributes to Hydrogen-Promoted Stomatal Closure in Arabidopsis.

    PubMed

    Xie, Yanjie; Mao, Yu; Zhang, Wei; Lai, Diwen; Wang, Qingya; Shen, Wenbiao

    2014-04-14

    The signaling role of hydrogen gas (H2) has attracted increasing attention from animals to plants. However, the physiological significance and molecular mechanism of H2 in drought tolerance are still largely unexplored. In this article, we report that abscisic acid (ABA) induced stomatal closure in Arabidopsis (Arabidopsis thaliana) by triggering intracellular signaling events involving H2, reactive oxygen species (ROS), nitric oxide (NO), and the guard cell outward-rectifying K(+) channel (GORK). ABA elicited a rapid and sustained H2 release and production in Arabidopsis. Exogenous hydrogen-rich water (HRW) effectively led to an increase of intracellular H2 production, a reduction in the stomatal aperture, and enhanced drought tolerance. Subsequent results revealed that HRW stimulated significant inductions of NO and ROS synthesis associated with stomatal closure in the wild type, which were individually abolished in the nitric reductase mutant nitrate reductase1/2 (nia1/2) or the NADPH oxidase-deficient mutant rbohF (for respiratory burst oxidase homolog). Furthermore, we demonstrate that the HRW-promoted NO generation is dependent on ROS production. The rbohF mutant had impaired NO synthesis and stomatal closure in response to HRW, while these changes were rescued by exogenous application of NO. In addition, both HRW and hydrogen peroxide failed to induce NO production or stomatal closure in the nia1/2 mutant, while HRW-promoted ROS accumulation was not impaired. In the GORK-null mutant, stomatal closure induced by ABA, HRW, NO, or hydrogen peroxide was partially suppressed. Together, these results define a main branch of H2-regulated stomatal movement involved in the ABA signaling cascade in which RbohF-dependent ROS and nitric reductase-associated NO production, and subsequent GORK activation, were causally involved. PMID:24733882

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

    PubMed Central

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

    2014-01-01

    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. PMID:25460738

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

    PubMed Central

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

    2014-01-01

    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

  8. Electron and Muon production cross-sections in quasielastic ?(?)-Nucleus scattering for E? < 1GeV

    NASA Astrophysics Data System (ADS)

    Akbar, F.; Alam, M. Rafi; Athar, M. Sajjad; Chauhan, S.; Singh, S. K.; Zaidi, F.

    2015-10-01

    In this paper, we have studied (anti)neutrino induced charged current quasielastic (CCQE) scattering from some nuclear targets in the energy region of E? < 1GeV. Our aim is to confront electron and muon production cross-sections relevant for ????e or ????e oscillation experiments. The effects due to lepton mass and its kinematic implications, radiative corrections, second class currents (SCCs) and uncertainties in the axial and pseudoscalar form factors are calculated for (anti)neutrino induced reaction cross-sections on free nucleon as well as the nucleons bound in a nucleus where nuclear medium effects influence the cross-section. For the nuclear medium effects, we have taken some versions of Fermi gas model (FGM) available in the literature. The results for (anti)neutrino-nucleus scattering cross-section per interacting nucleons are compared with the corresponding results in free nucleon case.

  9. Efficient transformation of DDT by peroxymonosulfate activated with cobalt in aqueous systems: Kinetics, products, and reactive species identification.

    PubMed

    Qin, Wenxiu; Fang, Guodong; Wang, Yujun; Wu, Tongliang; Zhu, Changyin; Zhou, Dongmei

    2016-04-01

    Recently, sulfate radical ( [Formula: see text] ) based-advanced oxidation technologies (AOTs) have been attracted great attention in the remediation of contaminated soil and groundwater. In the present study, Co(2+) ions activated peroxymonosulfate (PMS) system was used to degrade 1, 1, 1-trichloro-2, 2'bis(p-chlorophenyl) ethane (DDT) in aqueous solutions. It was found that DDT was efficiently degraded in the PMS/Co(II) solutions within several hours, and the degradation efficiency of DDT was dependent on the concentrations of PMS and Co(II), and the optimum molar ratio of PMS and Co(II) was 50:1. The degradation kinetics of DDT were well described with pseudo-first-order equations over a range of temperature (10-40 °C), and the activation energy that was calculated with Arrhenius equation was 72.3 ± 2.6 kJ/mol. Electron paramagnetic resonance (EPR) and GC-MS techniques were applied to identify the intermediates and reactive species for DDT degradation. The results indicated that [Formula: see text] and OH were the main reactive species accounting for DDT degradation. Dichlorobenzophenone, 4-chlorobenzoic acid and benzylalcohol were the dominant intermediates for DDT degradation, and the likely degradation pathway of DDT was proposed on the basis of these identified products. Increasing pH inhibited the formation of [Formula: see text] and OH, and thus decreased the catalytic degradation of DDT. Cl(-) ion was found to significantly inhibit, while [Formula: see text] and dissolved oxygen had limited effects on DDT degradation. PMID:26802265

  10. Reactive oxygen species-dependent nitric oxide production in reciprocal interactions of glioma and microglial cells.

    PubMed

    Shen, Shing-Chuan; Wu, Ming-Shun; Lin, Hui-Yi; Yang, Liang-Yo; Chen, Yi-Hsuan; Chen, Yen-Chou

    2014-12-01

    Conditioned mediums (CMs) from glioma cells U87, GBM-8401, and C6 significantly induced iNOS protein and NO production by microglial cells BV-2 but without altering the cell viability or cell-cycle progression of BV2 microglia. Significant increases in intracellular peroxide by U87-CM and C6-CM were detected by a DCHF-DA assay, and vitamin (Vit) C and N-acetyl cysteine (NAC)-reduced intracellular peroxide levels elicited by CMs lead to inhibition of iNOS/NO production The extracellular signal-regulated kinase (ERK) inhibitor, U0126, and c-Jun N-terminal kinase (JNK) inhibitor, SP600125, suppressed U87-CM- and C6-CM-induced iNOS/NO production by respectively blocking phosphorylated ERK (pERK) and JNK (pJNK) protein expressions stimulated by U87-CM and C6-CM. Increased migration of U87 and C6 glioma cells by a co-culture with BV-2 microglial cells or adding the nitric oxide (NO) donor, sodium nitroprusside (SNP) was observed, and that was blocked by adding an NO synthase (NOS) inhibitor, N-nitro L-arginine methyl ester (NAME). Contributions of ROS, pERK, and pJNK to the migration of glioma cells was further demonstrated in a transwell coculture system of U87 and C6 gliomas with BV-2 microglial cells. Furthermore, expressions of tumor necrosis factor (TNF)-? and monocyte chemoattractant protein (MCP)-1 messenger (m)RNA in U87 and C6 cells were detected by an RT-PCR, and TNF-? and MCP-1 induced iNOS protein expression in time- and concentration-dependent manners. Neutralization of TNF-? or MCP-1 in U87-CM and C6-CM using a TNF-? or MCP-1 antibody inhibited iNOS protein expression, and increased intracellular peroxide by TNF-? or MCP-1 was identified in BV-2 cells. The reciprocal activation of glioma cells and microglia via ROS-dependent iNOS/NO elevation at least partially mediated by TNF-? and MCP-1 is elucidated. PMID:24777714

  11. Low CD3+CD28-induced interleukin-2 production correlates with decreased reactive oxygen intermediate formation in neonatal T cells.

    PubMed

    Kilpinen, S; Hurme, M

    1998-06-01

    The capacity of neonatal T cells to secrete interleukin-2 (IL-2) has been reported to be variable. We analysed IL-2 production in purified neonatal and adult T cells using polyclonal activator phorbol ester + calcium ionophore (PDBu + iono) or receptor-mediated anti-CD3/anti-CD3+ anti-CD28 stimulation. PDBu + iono induced equally high IL-2 levels in both groups and, when stimulated with plate-bound anti-CD3 monoclonal antibody (mAb), the IL-2 secretion by neonatal cells was undetectable and adult cells produced low amounts of IL-2 (mean 331 +/- 86 pg/ml). The addition of anti-CD28 mAb to anti-CD3-stimulated cells markedly increased IL-2 production in both cell types, but levels of IL-2 in neonatal T cells remained clearly lower than those of adult T cells (respective mean values: 385 +/- 109 pg/ml and 4494 +/- 1199 pg/ml). As NF-kappa B is a critical transcription factor in the control of IL-2 expression, we next analysed its nuclear translocation in neonatal and adult T cells using the electrophoretic mobility shift assay and, because induction of reactive oxygen intermediates (ROI) is required for the activation of NF-kappa B, we also analysed levels of intracellular ROI in these cells using the ROI-reactive fluorochrome DCFH-DA and flow cytometry. In neonatal T cells NF-kappa B activation and ROI formation after anti-CD3 stimulation were low compared with adult T cells and, although addition of anti-CD28 mAb increased induction of NF-kappa B and ROI formation, levels similar to those of adults were not achieved. After PDBu + iono stimulation, the cells showed similar ROI formation and IL-2 secretion. Our results suggest that reduced IL-2 production by neonatal T cells is specific for anti-CD3 and anti-CD3+ anti-CD28-mediated stimulation and that these activators cannot effectively activate the ROI-NF-kappa B signalling pathway in neonatal T cells. PMID:9741337

  12. Oxidative phosphorylation efficiency, proton conductance and reactive oxygen species production of liver mitochondria correlates with body mass in frogs.

    PubMed

    Roussel, Damien; Salin, Karine; Dumet, Adeline; Romestaing, Caroline; Rey, Benjamin; Voituron, Yann

    2015-10-01

    Body size is a central biological parameter affecting most biological processes (especially energetics) and the mitochondrion is a key organelle controlling metabolism and is also the cell's main source of chemical energy. However, the link between body size and mitochondrial function is still unclear, especially in ectotherms. In this study, we investigated several parameters of mitochondrial bioenergetics in the liver of three closely related species of frog (the common frog Rana temporaria, the marsh frog Pelophylax ridibundus and the bull frog Lithobates catesbeiana). These particular species were chosen because of their differences in adult body mass. We found that mitochondrial coupling efficiency was markedly increased with animal size, which led to a higher ATP production (+70%) in the larger frogs (L. catesbeiana) compared with the smaller frogs (R. temporaria). This was essentially driven by a strong negative dependence of mitochondrial proton conductance on body mass. Liver mitochondria from the larger frogs (L. catesbeiana) displayed 50% of the proton conductance of mitochondria from the smaller frogs (R. temporaria). Contrary to our prediction, the low mitochondrial proton conductance measured in L. catesbeiana was not associated with higher reactive oxygen species production. Instead, liver mitochondria from the larger individuals produced significantly lower levels of radical oxygen species than those from the smaller frogs. Collectively, the data show that key bioenergetics parameters of mitochondria (proton leak, ATP production efficiency and radical oxygen species production) are correlated with body mass in frogs. This research expands our understanding of the relationship between mitochondrial function and the evolution of allometric scaling in ectotherms. PMID:26347565

  13. Mitochondrial reactive oxygen species production by fish muscle mitochondria: Potential role in acute heat-induced oxidative stress.

    PubMed

    Banh, Sheena; Wiens, Lilian; Sotiri, Emianka; Treberg, Jason R

    2016-01-01

    Acute heat challenge is known to induce cell-level oxidative stress in fishes. Mitochondria are well known for the capacity to make reactive oxygen species (ROS) and as such are often implicated as a source of the oxidants associated with this thermally-induced oxidative stress. This implication is often asserted, despite little direct data for mitochondrial ROS metabolism in fishes. Here we characterize mitochondrial ROS metabolism in three Actinopterygian fish species at two levels, the capacity for superoxide/H2O2 production and the antioxidant thiol-reductase enzyme activities. We find that red muscle mitochondria from all three species have measurable ROS production and respond to different assay conditions consistent with what might be anticipated; assuming similar relative contributions from difference ROS producing sites as found in rat skeletal muscle mitochondria. Although there are species and assay specific exceptions, fish mitochondria may have a greater capacity to produce ROS than that found in the rat when either normalized to respiratory capacity or determined at a common assay temperature. The interspecific differences in ROS production are not correlated with thiol-based antioxidant reductase activities. Moreover, mimicking an acute in vivo heat stress by comparing the impact of increasing assay temperature on these processes in vitro, we find evidence supporting a preferential activation of mitochondrial H2O2 production relative to the increase in the capacity of reductase enzymes to supply electrons to the mitochondrial matrix peroxidases. This supports the contention that mitochondria may be, at least in part, responsible for the ROS that lead to oxidative stress in fish tissues exposed to acute heat challenge. PMID:26456509

  14. Retinoic acid stimulation of VEGF secretion from human endometrial stromal cells is mediated by production of reactive oxygen species.

    PubMed

    Wu, Juanjuan; Hansen, Jason M; Hao, Lijuan; Taylor, Robert N; Sidell, Neil

    2011-02-15

    It is widely accepted that vascular endothelial growth factor (VEGF) is involved in angiogenic functions that are necessary for successful embryonic implantation. We have shown that retinoic acid (RA), which is known to play a necessary role in early events in pregnancy, can combine with transcriptional activators of VEGF (e.g. TPA, TGF-?, IL-1?) to rapidly induce VEGF secretion from human endometrial stromal cells through a translational mechanism of action. We have now determined that this stimulation of VEGF by RA is mediated through an increased production of cellular reactive oxygen species (ROS). Results indicated that RA, but not TPA or TGF-?, directly increases ROS production in endometrial stromal cells and that the co-stimulating activity of RA on VEGF secretion can be mimicked by direct addition of H2O2. Importantly, co-treatment of RA with TPA or TGF-? further stimulated ROS production in a fashion that positively correlated with levels of VEGF secretion. The antioxidants N-acetylcysteine and glutathione monoethyl ester inhibited both RA + TPA and RA + TGF-?-stimulated secretion of VEGF, as well as RA-induced ROS production. Treatment of cells with RA resulted in a shift in the glutathione (GSH) redox potential to a more oxidative state, suggesting that the transduction pathway leading to increased VEGF secretion is at least partially mediated through the antioxidant capacity of GSH couples. The specificity of this action on GSH-sensitive signalling pathways is suggested by the determination that RA had no effect on the redox potential of thioredoxin. Together, these findings predict a redox-mediated mechanism for retinoid regulation of localized VEGF secretion in the human endometrium that may be necessary for the successful establishment of pregnancy. PMID:21173077

  15. Induction of mitochondrial reactive oxygen species production by GSH mediated S-glutathionylation of 2-oxoglutarate dehydrogenase

    PubMed Central

    Mailloux, Ryan J.; Craig Ayre, D.; Christian, Sherri L.

    2016-01-01

    2-Oxoglutarate dehydrogenase (Ogdh) is an important mitochondria redox sensor that can undergo S-glutathionylation following an increase in H2O2 levels. Although S-glutathionylation is required to protect Ogdh from irreversible oxidation while simultaneously modulating its activity it remains unknown if glutathione can also modulate reactive oxygen species (ROS) production by the complex. We report that reduced (GSH) and oxidized (GSSG) glutathione control O2∙-/H2O2 formation by Ogdh through protein S-glutathionylation reactions. GSSG (1 mM) induced a modest decrease in Ogdh activity which was associated with a significant decrease in O2∙-/H2O2 formation. GSH had the opposite effect, amplifying O2∙-/H2O2 formation by Ogdh. Incubation of purified Ogdh in 2.5 mM GSH led to significant increase in O2∙-/H2O2 formation which also lowered NADH production. Inclusion of enzymatically active glutaredoxin-2 (Grx2) in reaction mixtures reversed the GSH-mediated amplification of O2∙-/H2O2 formation. Similarly pre-incubation of permeabilized liver mitochondria from mouse depleted of GSH showed an approximately ~3.5-fold increase in Ogdh-mediated O2∙-/H2O2 production that was matched by a significant decrease in NADH formation which could be reversed by Grx2. Taken together, our results demonstrate GSH and GSSG modulate ROS production by Ogdh through S-glutathionylation of different subunits. This is also the first demonstration that GSH can work in the opposite direction in mitochondria-amplifying ROS formation instead of quenching it. We propose that this regulatory mechanism is required to modulate ROS emission from Ogdh in response to variations in glutathione redox buffering capacity. PMID:26928132

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

    PubMed Central

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

    2011-01-01

    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

  17. Isochoric Burn, an Internally Consistent Method for the Reactant to Product Transformation in Reactive Flow

    SciTech Connect

    Reaugh, J E; Lee, E L

    2002-07-01

    Mixture rules for partially reacted explosives differ amongst various models. For instance, JWL++ uses a partial pressure addition to compute an average zonal pressure, Ignition and Growth requires pressure equilibration and thermal equilibration of temperature dependent JWL EOSs, CHEETAH In Line RF also assumes temperature and pressure equilibration. It has been suggested in the past that a more realistic equilibration scheme should comprise isentropic pressure equilibration of the separate reacted and unreacted phases. This turns out not to be a proper path for equilibration. Rather, we find that the only internally consistent method is the evaluation of the equilibrium pressure that satisfies the particular conditions of reactant and product resulting from deflagration in a fixed volume.

  18. Serum amyloid A induces reactive oxygen species (ROS) production and proliferation of fibroblast.

    PubMed

    Hatanaka, E; Dermargos, A; Armelin, H A; Curi, R; Campa, A

    2011-03-01

    Serum amyloid A (SAA) levels are elevated highly in acute phase response and elevated slightly and persistently in chronic diseases such as rheumatoid arthritis and diabetes. Given that fibroblasts exert profound effects on progression of inflammatory chronic diseases, the aim of this study was to investigate the response of fibroblasts to SAA. A dose-dependent increase in O(2) (-) levels was observed by treatment of fibroblasts with SAA (r = 099 and P ? 0001). In addition, the expression of p47-phox was up-regulated by SAA (P < 0001) and diphenyliodonium (DPI), a nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor, reduced the release of O(2) (-) by 50%. Also, SAA raised fibroblast proliferation (P < 0001) and this effect was completely abolished by the addition of anti-oxidants (P < 0001). These findings support the notion that, in chronic inflammatory sites, SAA activated fibroblast proliferation and ROS production. PMID:21175596

  19. Liver Fibrosis Can Be Induced by High Salt Intake through Excess Reactive Oxygen Species (ROS) Production.

    PubMed

    Wang, Guang; Yeung, Cheung-Kwan; Wong, Wing-Yan; Zhang, Nuan; Wei, Yi-Fan; Zhang, Jing-Li; Yan, Yu; Wong, Ching-Yee; Tang, Jun-Jie; Chuai, Manli; Lee, Kenneth Ka Ho; Wang, Li-Jing; Yang, Xuesong

    2016-02-24

    High salt intake has been known to cause hypertension and other side effects. However, it is still unclear whether it also affects fibrosis in the mature or developing liver. This study demonstrates that high salt exposure in mice (4% NaCl in drinking water) and chick embryo (calculated final osmolality of the egg was 300 mosm/L) could lead to derangement of the hepatic cords and liver fibrosis using H&E, PAS, Masson, and Sirius red staining. Meanwhile, Desmin immunofluorescent staining of mouse and chick embryo livers indicated that hepatic stellate cells were activated after the high salt exposure. pHIS3 and BrdU immunohistological staining of mouse and chick embryo livers indicated that cell proliferation decreased; as well, TUNEL analyses indicated that cell apoptosis increased in the presence of high salt exposure. Next, dihydroethidium staining on the cultured chick hepatocytes indicated the excess ROS was generated following high salt exposure. Furthermore, AAPH (a known inducer of ROS production) treatment also induced the liver fibrosis in chick embryo. Positive Nrf2 and Keap1 immunohistological staining on mouse liver suggested that Nrf2/Keap1 signaling was involved in high salt induced ROS production. Finally, the CCK8 assay was used to determine whether or not the growth inhibitory effect induced by high salt exposure can be rescued by antioxidant vitamin C. Meanwhile, the RT-PCR result indicated that the Nrf2/Keap1 downsteam genes including HO-1, NQO-1, and SOD2 were involved in this process. In sum, these experiments suggest that high salt intake would lead to high risk of liver damage and fibrosis in both adults and developing embryos. The pathological mechanism may be the result from an imbalance between oxidative stress and the antioxidant system. PMID:26843032

  20. Effects of nitrogen dioxide and its acid mist on reactive oxygen species production and antioxidant enzyme activity in Arabidopsis plants.

    PubMed

    Liu, Xiaofang; Hou, Fen; Li, Guangke; Sang, Nan

    2015-08-01

    Nitrogen dioxide (NO2) is one of the most common and harmful air pollutants. To analyze the response of plants to NO2 stress, we investigated the morphological change, reactive oxygen species (ROS) production and antioxidant enzyme activity in Arabidopsis thaliana (Col-0) exposed to 1.7, 4, 8.5, and 18.8 mg/m(3) NO2. The results indicate that NO2 exposure affected plant growth and chlorophyll (Chl) content, and increased oxygen free radical (O2(-)) production rate in Arabidopsis shoots. Furthermore, NO2 elevated the levels of lipid peroxidation and protein oxidation, accompanied by the induction of antioxidant enzyme activities and change of ascorbate (AsA) and glutathione (GSH) contents. Following this, we mimicked nitric acid mist under experimental conditions, and confirmed the antioxidant mechanism of the plant to the stress. Our results imply that NO2 and its acid mist caused pollution risk to plant systems. During the process, increased ROS acted as a signal to induce a defense response, and antioxidant status played an important role in plant protection against NO2/nitric acid mist-caused oxidative damage. PMID:26257351

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

    PubMed

    Sathishkumar, P; Murugesan, K; Palvannan, T

    2010-08-01

    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

  2. The Effects of New Alibernet Red Wine Extract on Nitric Oxide and Reactive Oxygen Species Production in Spontaneously Hypertensive Rats

    PubMed Central

    Kondrashov, Alexey; Vrankov, Stanislava; Dovinov, Ima; ev?k, Rudolf; Parohov, Jana; Barta, Andrej; Pech?ov, Olga; Kovacsov, Maria

    2012-01-01

    We aimed to perform a chemical analysis of both Alibernet red wine and an alcohol-free Alibernet red wine extract (AWE) and to investigate the effects of AWE on nitric oxide and reactive oxygen species production as well as blood pressure development in normotensive Wistar Kyoto (WKY) and spontaneously hypertensive rats (SHRs). Total antioxidant capacity together with total phenolic and selected mineral content was measured in wine and AWE. Young 6-week-old male WKY and SHR were treated with AWE (24,2?mg/kg/day) for 3 weeks. Total NOS and SOD activities, eNOS and SOD1 protein expressions, and superoxide production were determined in the tissues. Both antioxidant capacity and phenolic content were significantly higher in AWE compared to wine. The AWE increased NOS activity in the left ventricle, aorta, and kidney of SHR, while it did not change NOS activity in WKY rats. Similarly, increased SOD activity in the plasma and left ventricle was observed in SHR only. There were no changes in eNOS and SOD1 expressions. In conclusion, phenolics and minerals included in AWE may contribute directly to increased NOS and SOD activities of SHR. Nevertheless, 3 weeks of AWE treatment failed to affect blood pressure of SHR. PMID:22720118

  3. Enhancement of interleukin-8-induced chemotactic response and reactive oxygen species production in HL-60 cells expressing CXCR1.

    PubMed

    Kikuchi-Ueda, Takane; Tansho, Shigeru; Ono, Yasuo

    2012-06-01

    Neutrophils play a pivotal role in immunity against infection by ingesting and killing invading microbes. Neutrophils isolated from human peripheral blood have been used for a number of studies conducted for evaluation of immunomodulating drugs, cytokines, and microbe products. Human promyelocytic leukemia cells, HL-60, have been extensively studied because they can differentiate into neutrophil-like cells by addition of all-trans retinoic acid or dimethyl sulfoxide. For a system that would always allow experimental use of granulocytic cells in a uniformly activated state, we have established HL-60 cell lines with increased migratory activity by transducing the CXC chemokine receptor 1 (CXCR1) gene. When these cell lines were primed with CXC chemokine ligand 8 (IL-8), a slight increase in reactive oxygen species production induced by phorbol myristate acetate (PMA) or zymosan A stimuli was observed. A significance increase in migratory activity was noticed when the HL-60 cells transduced CXCR1 were stimulated with IL-8 in the Boyden chamber method. The gene-transduced HL-60 cell lines may be used as a substitute for neutrophils in screening the effects of various immunomodulating drugs on the migratory activity induced by IL-8. PMID:22009527

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

    PubMed Central

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

    2011-01-01

    Perfluorooctane sulfonate (PFOS) is a member of perfluoroalkyl acids (PFAA) containing an 8-carbon backbone. PFOS is a man-made chemical with carbon-fluorine bonds that are one of the strongest in organic chemistry and widely used in industry. Human occupational and environmental exposure to PFOS occurs globally. PFOS is non-biodegradable and 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 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

  5. Relation between cell death progression, reactive oxygen species production and mitochondrial membrane potential in fermenting Saccharomyces cerevisiae cells under heat-shock conditions.

    PubMed

    Pyatrikas, Darya V; Fedoseeva, Irina V; Varakina, Nina N; Rusaleva, Tatyana M; Stepanov, Alexei V; Fedyaeva, Anna V; Borovskii, Gennadii B; Rikhvanov, Eugene G

    2015-06-01

    Moderate heat shock increased reactive oxygen species (ROS) production that led to cell death in glucose-grown Saccharomyces cerevisiae cells. Conditions that disturb mitochondrial functions such as treatment by uncouplers and petite mutation were shown to inhibit ROS production and protects cell from thermal death. Hence, mitochondria are responsible for ROS production and play an active role in cell death. An increase in ROS production was accompanied by hyperpolarization of inner mitochondrial membrane. All agents suppressing hyperpolarization also suppressed heat-induced ROS production. It was supposed that generation of ROS under moderate heat shock in glucose-grown S. cerevisiae cells is driven by the mitochondrial membrane potential. PMID:25991811

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

    PubMed Central

    da Silva, Michelle Reis; de Sá, Lívian Ribeiro Vasconcelos; Russo, Carlos; Scio, Elita; Ferreira-Leitão, Viridiana Santana

    2010-01-01

    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

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

    PubMed

    da Silva, Michelle Reis; de S, Lvian Ribeiro Vasconcelos; Russo, Carlos; Scio, Elita; Ferreira-Leito, Viridiana Santana

    2011-01-01

    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?mgL(-1), considering the following parameters: temperature (20-45C), H(2)O(2) concentration (0-4.44?mmolL(-1)), and reaction time (5 minutes, 1 and 24?h). The following conditions: 35C, 0.55?mmolL(-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

  8. Raman scattering and associated fast electron production. Final technical report, April 16, 1984-April 15, 1985

    SciTech Connect

    Brooks, R.D.; Pietrzyk, Z.A.

    1985-08-01

    High energy electrons in plasmas have been attributed to various causes including trapping by electron plasma waves created by stimulated Raman scattering. A theory, consistent with experimental results, based on the acceleration of trapped electrons by such electron plasma waves as they propagate in the presence of a density gradient away from the region where they are created is presented. Single particle simulations show accelerating voltages as high as 20 GV/m.

  9. Production of ?- in deep inelastic scattering with ZEUS detector at HERA

    NASA Astrophysics Data System (ADS)

    Nasir, N. Mohammad; Wan Abdullah, W. A. T.

    2016-01-01

    In this paper, we discussed about the possible mechanism on how strange baryon are being produced. The discovery of strange quarks in cosmic rays before the quarks model being proposed makes the searches become more interesting, as it has long lifetimes. The inclusive deep inelastic scattering of ?- has been studied in electron-proton collisions with ZEUS detector at HERA. We also studied HERA kinematics and phase space.

  10. Investigation of the photochemical reactivity of soot particles derived from biofuels toward NO2. A kinetic and product study.

    PubMed

    Romanías, Manolis N; Dagaut, Philippe; Bedjanian, Yuri; Andrade-Eiroa, Auréa; Shahla, Roya; Emmanouil, Karafas S; Papadimitriou, Vassileios C; Spyros, Apostolos

    2015-03-12

    In the current study, the heterogeneous reaction of NO2 with soot and biosoot surfaces was investigated in the dark and under illumination relevant to atmospheric conditions (J(NO2) = 0.012 s(-1)). A flat-flame burner was used for preparation and collection of soot samples from premixed flames of liquid fuels. The biofuels were prepared by mixing 20% v/v of (i) 1-butanol (CH3(CH2)3OH), (ii) methyl octanoate (CH3(CH2)6COOCH3), (iii) anhydrous diethyl carbonate (C2H5O)2CO and (iv) 2,5 dimethyl furan (CH3)2C4H2O additive compounds in conventional kerosene fuel (JetA-1). Experiments were performed at 293 K using a low-pressure flow tube reactor (P = 9 Torr) coupled to a quadrupole mass spectrometer. The initial and steady-state uptake coefficients, γ0 and γ(ss), respectively, as well as the surface coverage, N(s), were measured under dry and humid conditions. Furthermore, the branching ratios of the gas-phase products NO (∼80-100%) and HONO (<20%) were determined. Soot from JetA-1/2,5-dimethyl furan was the most reactive [γ0 = (29.1 ± 5.8) × 10(-6), γ(ss)(dry) = (9.09 ± 1.82) × 10(-7) and γ(ss)(5.5%RH) = (14.0 ± 2.8)(-7)] while soot from JetA-1/1-butanol [γ0 = (2.72 ± 0.544) × 10(-6), γ(ss)(dry) = (4.57 ± 0.914) × 10(-7), and γ(ss)(5.5%RH) = (3.64 ± 0.728) × 10(-7)] and JetA-1/diethyl carbonate [γ0 = (2.99 ± 0.598) × 10(-6), γ(ss)(dry) = (3.99 ± 0.798) × 10(-7), and γ(ss)(5.5%RH) = (4.80 ± 0.960) × 10(-7)] were less reactive. To correlate the chemical reactivity with the physicochemical properties of the soot samples, their chemical composition was analyzed employing Raman spectroscopy, NMR, and high-performance liquid chromatography. In addition, the Brunauer-Emmett-Teller adsorption isotherms and the particle size distributions were determined employing a Quantachrome Nova 2200e gas sorption analyzer. The analysis of the results showed that factors such as (i) soot mass collection rate, (ii) porosity of the particles formed, (iii) aromatic fraction, and (iv) pre-existence of nitro-containing species in soot samples (formed during the combustion process) can be used as indicators of soot reactivity with NO2. PMID:25686032

  11. Reactivity of β-blockers/agonists with aqueous permanganate. Kinetics and transformation products of salbutamol.

    PubMed

    Rodríguez-Álvarez, Tania; Rodil, Rosario; Quintana, José Benito; Cela, Rafael

    2015-08-01

    The possible oxidation of two β-blockers, atenolol and propranolol, and one β-agonist, salbutamol, with aqueous potassium permanganate (KMnO4) was investigated by liquid chromatography-quadrupole-time-of-flight-mass spectrometry (LC-QTOF-MS). Under strong oxidation conditions (2 mg L(-1) KMnO4, 24 h), only salbutamol did significantly react. In this way, the oxidation kinetics of salbutamol was further investigated at different concentrations of KMnO4, chloride, phosphate and sample pH by means of a full factorial experimental design. Depending on these factors, half-lives were in the range 1-144 min for drug and it was observed that KMnO4 concentration was the most significant factor, resulting in increased reaction rate as it is increased. Moreover, the reaction of salbutamol is also enhanced at basic pH and to a minor extent by the presence of phosphates, being both factors more relevant at low KMnO4 concentrations. The use of an accurate-mass LC-QTOF-MS system permitted the identification of a total of seven transformation products (TPs). The transformation path of the drug begins by the attack of KMnO4 on two double bonds of the aromatic ring of salbutamol via 3 + 2 and 2 + 2 addition reactions, which resulted in the ring opening and that continues with oxidative reactions to finally produce smaller size TPs, ending with tert-butyl-formamide, as the smallest TP identified. Reaction in real samples showed a slower and partial oxidation of the pharmaceutical, due to other competing water organic constituents, but still exceeding 60%. Moreover, the software predicted toxicity of TPs indicates that they are expected not to be more toxic than salbutamol, in contrast to the results obtained for the predicted toxicity of chlorination TPs, excepting predicted developmental toxicity. PMID:25965887

  12. Cytoplasmic Alkalization Precedes Reactive Oxygen Species Production during Methyl Jasmonate- and Abscisic Acid-Induced Stomatal Closure1

    PubMed Central

    Suhita, Dontamala; Raghavendra, Agepati S.; Kwak, June M.; Vavasseur, Alain

    2004-01-01

    Signaling events during abscisic acid (ABA) or methyl jasmonate (MJ)-induced stomatal closure were examined in Arabidopsis wild type, ABA-insensitive (ost1-2), and MJ-insensitive mutants (jar1-1) in order to examine a crosstalk between ABA and MJ signal transduction. Some of the experiments were performed on epidermal strips of Pisum sativum. Stomata of jar1-1 mutant plants are insensitive to MJ but are able to close in response to ABA. However, their sensitivity to ABA is less than that of wild-type plants. Reciprocally, the stomata of ost1-2 are insensitive to ABA but are able to close in response to MJ to a lesser extent compared to wild-type plants. Both MJ and ABA promote H2O2 production in wild-type guard cells, while exogenous application of diphenylene iodonium (DPI) chloride, an inhibitor of NAD(P)H oxidases, results in the suppression of ABA- and MJ-induced stomatal closure. ABA elevates H2O2 production in wild-type and jar1-1 guard cells but not in ost1-2, whereas MJ induces H2O2 production in both wild-type and ost1-2 guard cells, but not in jar1-1. MJ-induced stomatal closing is suppressed in the NAD(P)H oxidase double mutant atrbohD/F and in the outward potassium channel mutant gork1. Furthermore, MJ induces alkalization in guard cell cytosol, and MJ-induced stomatal closing is inhibited by butyrate. Analyses of the kinetics of cytosolic pH changes and reactive oxygen species (ROS) production show that the alkalization of cytoplasm precedes ROS production during the stomatal response to both ABA and MJ. Our results further indicate that JAR1, as OST1, functions upstream of ROS produced by NAD(P)H oxidases and that the cytoplasmic alkalization precedes ROS production during MJ or ABA signal transduction in guard cells. PMID:15064385

  13. Isoflurane differentially modulates mitochondrial reactive oxygen species production via forward versus reverse electron transport flow: Implications for preconditioning

    PubMed Central

    Hirata, Naoyuki; Shim, Yon Hee; Pravdic, Danijel; Lohr, Nicole L.; Pratt, Philip F.; Weihrauch, Dorothee; Kersten, Judy R.; Warltier, David C; Bosnjak, Zeljko J.; Bienengraeber, Martin

    2012-01-01

    Backround Reactive oxygen species (ROS) mediate the effects of anesthetic precondition to protect against ischemia and reperfusion injury, but the mechanisms of ROS generation remain unclear. In this study, we investigated if mitochondria-targeted antioxidant (mitotempol) abolishes the cardioprotective effects of anesthetic preconditioning. Further, we investigated the mechanism by which isoflurane alters ROS generation in isolated mitochondria and submitochondrial particles. Methods Rats were pretreated with 0.9% saline, 3.0 mg/kg mitotempol in the absence or presence of 30 min exposure to isoflurane. Myocardial infarction was induced by left anterior descending artery occlusion for 30 min followed by reperfusion for 2h and infarct size measurements. Mitochondrial ROS production was determined spectrofluorometrically. The effect of isoflurane on enzymatic activity of mitochondrial respiratory complexes was also determined. Results Isoflurane reduced myocardial infarct size (409 % = meanSD) compared to control experiments (604 %). Mitotempol abolished the cardioprotective effects of anesthetic preconditioning (609%). Isoflurane enhanced ROS generation in submitochondrial particles with NADH, but not with succinate, as substrate. In intact mitochondria, isoflurane enhanced ROS production in the presence of rotenone, antimycin A, or ubiquinone when pyruvate and malate were substrates, but isoflurane attenuated ROS production when succinate was substrate. Mitochondrial respiratory experiments and electron transport chain complex assays revealed that isoflurane inhibited only complex I activity. Conclusions The results demonstrated that isoflurane produces ROS at complex I and III of the respiratory chain via the attenuation of complex I activity. The action on complex I decreases unfavorable reverse electron flow and ROS release in myocardium during reperfusion. PMID:21862887

  14. Salvianolate inhibits reactive oxygen species production in H2O2-treated mouse cardiomyocytes in vitro via the TGF? pathway

    PubMed Central

    Fei, Ai-hua; Cao, Qing; Chen, Shu-yan; Wang, Hai-rong; Wang, Fei-long; Pan, Shu-ming; Lin, Zhao-fen

    2013-01-01

    Aim: To investigate the effects of salvianolate, a water-soluble active compound from Salvia miltiorrhiza Bunge, on reactive oxygen species (ROS) production in mouse cardiomyocytes in vitro. Methods: Primary ventricular cardiomyocytes were prepared from neonatal mouse. The cell viability was determined using MTT assay. Culture medium for each treatment was collected for measuring the levels of NO, iNOS, total antioxidant capacity (TAOC) and transforming growth factor ?1 (TGF?1). TGF?1 and Smad2/3 expression in the cells was detected with Western blotting. Results: H2O2 (1.25 mmol/L) did not significantly affect the cell viability, whereas the high concentration of salvianolate (5 g/L) alone dramatically suppressed the cell viability. Treatment of the cells with H2O2 (1.25 mmol/L) markedly increased ROS and iNOS production, and decreased the levels of NO, TAOC and TGF?1 in the culture medium. Furthermore, the H2O2 treatment significantly increased TGF?1 and Smad2/3 expression in the cells. Addition of salvianolate (0.05, 0.1, and 0.5 g/L) concentration-dependently reversed the H2O2-induced alterations in the culture medium; addition of salvianolate (0.05 g/L) reversed the H2O2-induced increases of TGF?1 and Smad2/3 expression in the cells. Blockage of TGF?1 with its antibody (1 mg/L) abolished the above mentioned effects of salvianolate. Conclusion: Salvianolate inhibits ROS and iNOS production and increases TAOC and NO levels in H2O2-treated cardiomyocytes in vitro via downregulation of Smad2/3 and TGF?1 expression. High concentration of salvianolate causes cytotoxicity in mouse cardiomyocytes. PMID:23524570

  15. Hypothesis on Skeletal Muscle Aging: Mitochondrial Adenine Nucleotide Translocator Decreases Reactive Oxygen Species Production While Preserving Coupling Efficiency

    PubMed Central

    Diolez, Philippe; Bourdel-Marchasson, Isabelle; Calmettes, Guillaume; Pasdois, Philippe; Detaille, Dominique; Rouland, Richard; Gouspillou, Gilles

    2015-01-01

    Mitochondrial membrane potential is the major regulator of mitochondrial functions, including coupling efficiency and production of reactive oxygen species (ROS). Both functions are crucial for cell bioenergetics. We previously presented evidences for a specific modulation of adenine nucleotide translocase (ANT) appearing during aging that results in a decrease in membrane potential - and therefore ROS productionbut surprisingly increases coupling efficiency under conditions of low ATP turnover. Careful study of the bioenergetic parameters (oxidation and phosphorylation rates, membrane potential) of isolated mitochondria from skeletal muscles (gastrocnemius) of aged and young rats revealed a remodeling at the level of the phosphorylation system, in the absence of alteration of the inner mitochondrial membrane (uncoupling) or respiratory chain complexes regulation. We further observed a decrease in mitochondrial affinity for ADP in aged isolated mitochondria, and higher sensitivity of ANT to its specific inhibitor atractyloside. This age-induced modification of ANT results in an increase in the ADP concentration required to sustain the same ATP turnover as compared to young muscle, and therefore in a lower membrane potential under phosphorylatingin vivoconditions. Thus, for equivalent ATP turnover (cellular ATP demand), coupling efficiency is even higher in aged muscle mitochondria, due to the down-regulation of inner membrane proton leak caused by the decrease in membrane potential. In the framework of the radical theory of aging, these modifications in ANT function may be the result of oxidative damage caused by intra mitochondrial ROS and may appear like a virtuous circle where ROS induce a mechanism that reduces their production, without causing uncoupling, and even leading in improved efficiency. Because of the importance of ROS as therapeutic targets, this new mechanism deserves further studies. PMID:26733871

  16. Sinoporphyrin sodium, a novel sensitizer, triggers mitochondrial-dependent apoptosis in ECA-109 cells via production of reactive oxygen species

    PubMed Central

    Wang, Haiping; Wang, Xiaobing; Zhang, Shaoliang; Wang, Pan; Zhang, Kun; Liu, Quanhong

    2014-01-01

    Background Sonodynamic therapy (SDT) is a promising method that uses ultrasound to activate certain chemical sensitizers for the treatment of cancer. The purpose of this study was to investigate the sonoactivity of a novel sensitizer, sinoporphyrin sodium (DVDMS), and its sonotoxicity in an esophageal cancer (ECA-109) cell line. Methods The fluorescence intensity of DVDMS, hematoporphyrin, protoporphyrin IX, and Photofrin II was detected by fluorescence microscopy and flow cytometry. Generation of singlet oxygen was measured using a 1, 3-diphenylisobenzofuran experiment. A 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide assay was used to examine cell viability. Production of reactive oxygen species (ROS) and destabilization of the mitochondrial membrane potential were assessed by flow cytometry. Apoptosis was analyzed using Annexin-PE/7-amino-actinomycin D staining. Confocal microscopy was performed to assess mitochondrial damage and identify release of cytochrome C after treatment. Western blots were used to determine expression of oxidative stress-related and apoptosis-associated protein. Ultrastructural changes in the cell were studied by scanning electron microscopy. Results DVDMS showed higher autofluorescence intensity and singlet oxygen production efficiency compared with other photosensitizers in both cancerous and normal cells. Compared with hematoporphyrin, DVDMS-mediated SDT was more cytotoxic in ECA-109 cells. Abundant intracellular ROS was found in the SDT groups, and the cytotoxicity induced by SDT was effectively remitted by ROS scavengers. DVDMS located mainly to the mitochondria of ECA-109 cells, which were seriously damaged after exposure to SDT. Release of cytochrome C, an increased rate of apoptosis, and activated apoptosis protein were detected in the SDT group. In addition, relatively severe cell damage was observed on scanning electron microscopy after treatment with DVDMS and SDT. Conclusion These results suggest that DVDMS could be activated by ultrasound, and that DVDMS mediates SDT-induced mitochondrial-dependent apoptosis in ECA-109 cells via production of ROS. PMID:25028547

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

    PubMed Central

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

    2014-01-01

    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

  18. The inhibitory effect of zinc on cadmium-induced cell apoptosis and reactive oxygen species (ROS) production in cell cultures.

    PubMed

    Szuster-Ciesielska, A; Stachura, A; Słotwińska, M; Kamińska, T; Sniezko, R; Paduch, R; Abramczyk, D; Filar, J; Kandefer-Szerszeń, M

    2000-04-14

    The prevention of apoptosis by Zn(2+) is a well-known phenomenon. Both in in vitro and in vivo Zn(2+) supplementation prevents apoptosis induced by a variety of agents, among them by cadmium ions. The target for protective action of Zn ions on cell apoptosis is still unknown. In this paper we have evaluated the effect of in vitro ZnCl(2) supplementation at a concentration corresponding to the physiological level (10 microM) and higher (50 microM), on apoptosis induced with different Cd concentrations in two cell types: HeLa human tumor cell line and bovine aorta endothelial cells (BAECs). We demonstrated that Zn supplementation, especially at 10 microM concentration, significantly inhibited apoptosis in both types of cells. To assess the mechanism involved in the Zn effect we examined the influence of Zn supplementation on Cd accumulation in cells, Cd-induced superoxide anion (O(2)(-)) and hydrogen peroxide (H(2)O(2)) production. Zn caused 1.2-2.0-fold inhibition of Cd accumulation, 1.2-2.0-fold inhibition of Cd-induced apoptotic cell death, 1.1-2.0-fold decrease in reactive oxygen species (ROS) production in HeLa cells and in BAECs. These results indicate that inhibition of Cd-induced apoptosis in cells by Zn might be due, not only by inhibition of Cd accumulation in cells but, at least in part, to inhibition of Cd-induced production of ROS, which in turn are known as strong inducers of apoptosis. PMID:10771141

  19. 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

  20. P11 Resonances with Dubna-Mainz-Taipei dynamical model for πN scattering and pion electromagnetic production

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

    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 πN and γπ reactions.

  1. Phenylethynyl reactive diluents

    NASA Technical Reports Server (NTRS)

    Bryant, Robert G. (inventor.); Jensen, Brian J. (inventor.); Hergenrother, Paul M. (inventor.)

    1995-01-01

    A composition of matter having a specified general structure is employed to terminate a nucleophilic reagent, resulting in the exclusive production of phenylethynyl terminated reactive oligomers which display unique thermal characteristics. A reactive diluent having a specified general structure is employed to decrease the melt viscosity of a phenylethynyl terminated reactive oligomer and to subsequently react with to provide a thermosetting material of enhanced density. These materials have features which make them attractive candidates for use as composite matrices and adhesives.

  2. Anethole induces apoptotic cell death accompanied by reactive oxygen species production and DNA fragmentation in Aspergillus fumigatus and Saccharomyces cerevisiae.

    PubMed

    Fujita, Ken-Ichi; Tatsumi, Miki; Ogita, Akira; Kubo, Isao; Tanaka, Toshio

    2014-02-01

    trans-Anethole (anethole), a major component of anise oil, has a broad antimicrobial spectrum, and antimicrobial activity that is weaker than that of other antibiotics on the market. When combined with polygodial, nagilactone E, and n-dodecanol, anethole has been shown to possess significant synergistic antifungal activity against a budding yeast, Saccharomyces cerevisiae, and a human opportunistic pathogenic yeast, Candida albicans. However, the antifungal mechanism of anethole has not been completely determined. We found that anethole stimulated cell death of a human opportunistic pathogenic fungus, Aspergillus fumigatus, in addition to S. cerevisiae. The anethole-induced cell death was accompanied by reactive oxygen species production, metacaspase activation, and DNA fragmentation. Several mutants of S. cerevisiae, in which genes related to the apoptosis-initiating execution signals from mitochondria were deleted, were resistant to anethole. These results suggest that anethole-induced cell death could be explained by oxidative stress-dependent apoptosis via typical mitochondrial death cascades in fungi, including A. fumigatus and S. cerevisiae. PMID:24393541

  3. Human Leukemic Cells performing Oxidative Phosphorylation (OXPHOS) Generate an Antioxidant Response Independently of Reactive Oxygen species (ROS) Production.

    PubMed

    Khan, Abrar Ul Haq; Rathore, Moeez G; Allende-Vega, Nerea; Vo, Dang-Nghiem; Belkhala, Sana; Orecchioni, Stefania; Talarico, Giovanna; Bertolini, Francesco; Cartron, Guillaume; Lecellier, Charles-Henri; Villalba, Martin

    2016-01-01

    Tumor cell metabolism is altered during leukemogenesis. Cells performing oxidative phosphorylation (OXPHOS) generate reactive oxygen species (ROS) through mitochondrial activity. To limit the deleterious effects of excess ROS, certain gene promoters contain antioxidant response elements (ARE), e.g. the genes NQO-1 and HO-1. ROS induces conformational changes in KEAP1 and releases NRF2, which activates AREs. We show in vitro and in vivo that OXPHOS induces, both in primary leukemic cells and cell lines, de novo expression of NQO-1 and HO-1 and also the MAPK ERK5 and decreases KEAP1 mRNA. ERK5 activates the transcription factor MEF2, which binds to the promoter of the miR-23a-27a-24-2 cluster. Newly generated miR-23a destabilizes KEAP1 mRNA by binding to its 3'UTR. Lower KEAP1 levels increase the basal expression of the NRF2-dependent genes NQO-1 and HO-1. Hence, leukemic cells performing OXPHOS, independently of de novo ROS production, generate an antioxidant response to protect themselves from ROS. PMID:26870816

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

    PubMed Central

    Nazarewicz, Rafal R.

    2013-01-01

    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, 10851094. PMID:22443458

  5. Human Leukemic Cells performing Oxidative Phosphorylation (OXPHOS) Generate an Antioxidant Response Independently of Reactive Oxygen species (ROS) Production

    PubMed Central

    Khan, Abrar Ul Haq; Rathore, Moeez G.; Allende-Vega, Nerea; Vo, Dang-Nghiem; Belkhala, Sana; Orecchioni, Stefania; Talarico, Giovanna; Bertolini, Francesco; Cartron, Guillaume; Lecellier, Charles-Henri; Villalba, Martin

    2015-01-01

    Tumor cell metabolism is altered during leukemogenesis. Cells performing oxidative phosphorylation (OXPHOS) generate reactive oxygen species (ROS) through mitochondrial activity. To limit the deleterious effects of excess ROS, certain gene promoters contain antioxidant response elements (ARE), e.g. the genes NQO-1 and HO-1. ROS induces conformational changes in KEAP1 and releases NRF2, which activates AREs. We show in vitro and in vivo that OXPHOS induces, both in primary leukemic cells and cell lines, de novo expression of NQO-1 and HO-1 and also the MAPK ERK5 and decreases KEAP1 mRNA. ERK5 activates the transcription factor MEF2, which binds to the promoter of the miR-23a–27a–24-2 cluster. Newly generated miR-23a destabilizes KEAP1 mRNA by binding to its 3′UTR. Lower KEAP1 levels increase the basal expression of the NRF2-dependent genes NQO-1 and HO-1. Hence, leukemic cells performing OXPHOS, independently of de novo ROS production, generate an antioxidant response to protect themselves from ROS. PMID:26870816

  6. Aquaporin8 regulates cellular development and reactive oxygen species production, a critical component of virulence in Botrytis cinerea.

    PubMed

    An, Bang; Li, Boqiang; Li, Hua; Zhang, Zhanquan; Qin, Guozheng; Tian, Shiping

    2016-03-01

    Aquaporins (AQPs) are ubiquitous in nearly all organisms, mediating selective and rapid flux of water across biological membranes. The role of AQPs in phytopathogenic fungi is poorly understood. Orthologs of AQP genes in Botrytis cinerea were identified and knocked out. The effects of AQPs on hyphal growth and conidiation, formation of infection structures and virulence on plant hosts were examined. The role of AQP8 in reactive oxygen species (ROS) production, distribution and transport were further determined. Among eight AQPs, only AQP8 was essential for the ability of B. cinerea to infect plants. AQP8 was demonstrated to be an intrinsic plasma membrane protein, which may function as a channel and mediate hydrogen peroxide uptake. Deletion of AQP8 in B. cinerea completely inhibited the development of conidia and infection structures, and significantly affected noxR expression. Further observations revealed that both AQP8 and noxR impacted ROS distribution in the hyphal tips of B. cinerea. Moreover, AQP8 affected the expression of a mitochondrial protein, NQO1. A knockout mutant of NQO1 was observed to display reduced virulence. These data lead to a better understanding of the important role of AQP8 in the development and pathogenesis of plant pathogens. PMID:26527167

  7. Autophagy inhibition enhances silibinin-induced apoptosis by regulating reactive oxygen species production in human prostate cancer PC-3 cells.

    PubMed

    Kim, Sang-Hun; Kim, Kwang-Youn; Yu, Sun-Nyoung; Park, Seul-Ki; Choi, Hyeun-Deok; Ji, Jae-Hoon; Ahn, Soon-Cheol

    Silibinin is a major bioactive component of silymarin and has anticancer effects on cancer cell line and has been used as a supportive therapy for chronic inflammatory liver condition. These anticancer effects of silibinin have been demonstrated both in vitro and in vivo cancer models. Although various evidences showed apoptosis signaling pathways by silibinin, there is no report to address the clearly mechanism of silibinin-induced autophagy in prostate cancer PC-3 cells. Our study showed that silibinin triggered autophagy through up-regulation of microtubule-associated protein 1 light chain 3 (LC3)-II, formation of acidic vesicular organelles (AVO) and punctuate of GFP-LC3, which was inhibited by 3-methyladenine (3-MA), an inhibitor of specific autophagy. In addition, silibinin induced autophagy through production of reactive oxygen species (ROS). Inhibition of ROS with diphenyleneiodonium (DPI), a ROS inhibitor, attenuated silibinin-triggered autophagy. Inhibition of autophagy with 3-MA enhanced the silibinin-induced apoptosis through the regulation of caspase-3 and PARP. These results suggested that silibinin induced autophagy by regulating ROS and its mechanism played a protective role against apoptosis in PC-3 cells. PMID:26522224

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

    PubMed

    Zhou, Xiaoyuan; Rauchfuss, Thomas B

    2013-02-01

    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

  9. The uremic toxin indoxyl sulfate exacerbates reactive oxygen species production and inflammation in 3T3-L1 adipose cells.

    PubMed

    Stockler-Pinto, Milena B; Saldanha, Juliana F; Yi, Dan; Mafra, Denise; Fouque, Denis; Soulage, Christophe O

    2016-03-01

    Inflammation and oxidative stress are common features of patients with chronic kidney disease (CKD) and many uremic solutes retained in these patients could be involved in these processes, among which protein-bound solutes such as indoxyl sulfate (IS). White adipose tissue recently gained attention as an important source of inflammation and oxidative stress. To examine the effect of IS on adipocytes, 3T3-L1 adipose cells were incubated with IS to mimic the conditions encountered in uremic patients. Incubation of adipose cells with IS increased reactive oxygen species production generated mainly through activation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase since it was prevented by the NADPH oxidase inhibitor apocynin. Exposure to IS furthermore exacerbated the secretion of tumor necrosis factor-? and interleukin-6 by adipose cells. This inflammatory response was prevented by NADPH oxidase inhibition pinpointing the pivotal role of intracellular oxidative stress. IS induces adipocyte perturbation and promotes inflammatory state mainly through induction of oxidative stress. IS, a uremic toxin, accumulates in CKD patients could, therefore, be an important mediator of adipocyte dysfunction in these patients. PMID:26617268

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

    PubMed Central

    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

    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

  11. Constitutive NF-κB activation and tumor-growth promotion by Romo1-mediated reactive oxygen species production

    SciTech Connect

    Chung, Jin Sil; Lee, Sora; Yoo, Young Do

    2014-08-08

    Highlights: • Romo1 expression is required for constitutive nuclear DNA-binding activity of NF-κB. • Romo1 depletion suppresses tumor growth in vivo. • Romo1 presents a potential therapeutic target for diseases. - Abstract: Deregulation of nuclear factor-κB (NF-κB) and related pathways contribute to tumor cell proliferation and invasion. Mechanisms for constitutive NF-κB activation are not fully explained; however, the underlying defects appear to generate and maintain pro-oxidative conditions. In hepatocellular carcinoma (HCC) tissues, up-regulation of reactive oxygen species modulator 1 (Romo1) correlates positively with tumor size. In the present study, we showed that Romo1 expression is required to maintain constitutive nuclear DNA-binding activity of NF-κB and transcriptional activity through constitutive IκBα phosphorylation. Overexpression of Romo1 promoted p65 nuclear translocation and DNA-binding activity. We also show that Romo1 depletion suppressed anchorage-independent colony formation by HCC cells and suppressed tumor growth in vivo. Based on these findings, Romo1 may be a principal regulatory factor in the maintenance of constitutive NF-κB activation in tumor cells. In the interest of anti-proliferative treatments for cancer, Romo1 may also present a productive target for drug development.

  12. Aluminum induces neurodegeneration and its toxicity arises from increased iron accumulation and reactive oxygen species (ROS) production.

    PubMed

    Wu, Zhihao; Du, Yumei; Xue, Hua; Wu, Yongsheng; Zhou, Bing

    2012-01-01

    The neurotoxicity of aluminum (Al) - the most abundant metal element on earth - has been known for years. However, the mechanism of Al-induced neurodegeneration and its relationship to Alzheimer's disease are still controversial. In particular, in vivo functional data are lacking. In a Drosophila model with chronic dietary Al overloading, general neurodegeneration and several behavioral changes were observed. Al-induced neurodegeneration is independent of ?-amyloid or tau-associated toxicity, suggesting they act in different molecular pathways. Interestingly, Drosophila frataxin (dfh), which causes Friedreich's ataxia if mutated in humans, displayed an interacting effect with Al, suggesting Friedreich's ataxia patients might be more susceptible to Al toxicity. Al-treated flies accumulated large amount of iron and reactive oxygen species (ROS), and exhibited elevated SOD2 activity. Genetic and pharmacological efforts to reduce ROS or chelate excess Fe significantly mitigated Al toxicity. Our results indicate that Al toxicity is mediated through ROS production and iron accumulation and suggest a remedial route to reduce toxicity due to Al exposure. PMID:20674094

  13. Reactivity of Tannic Acid with Common Corrosion Products and Its Influence on the Hydrolysis of Iron in Alkaline Solutions

    NASA Astrophysics Data System (ADS)

    Jan, J. A.; Araz, E. Y.; Iglesias, J.; Delgado, Y.

    2003-06-01

    To ascertain the role of tannic acid in the anticorrosive protection of steels, the reaction between 5% tannic acid aqueous solutions with lepidocrocite, goethite, superparamagnetic goethite, akaganeite, poorly crystalline maghemite, magnetite and hematite was studied using color changes, infrared and Mssbauer spectroscopy. After three months of interaction with lepidocrocite, the formation of an iron tannate complex was detected by its dark blue color and confirmed by infrared and Mssbauer analysis. Evidence for the chemical transformation was obtained for goethite in nanoparticles and poorly crystalline maghemite after reaction for six months. The other iron compounds do not transform to another oxide or phase upon treatment with the tannic acid solution. These results showed that lepidocrocite is the most reactive phase and that the size and degree of crystallinity have strong influence on the formation of the tannate complexes. The precipitation of iron phases from alkaline solutions of iron (II) sulfate heptahydrate containing different amount of tannic acid and potassium nitrate as oxidative agent was also studied. Mssbauer and infrared results show that in the absence of tannic acid some common rust components are obtained (viz. goethite, superparamagnetic goethite, maghemite and non-stoichiometric magnetite). The presence of 0.1% tannic acid in a low alkalinity solution results in the precipitation of iron oxyhydroxides and some iron tannates. Concentrations of 1% tannic acid are required for the formation of the tannates complexes as main reaction product.

  14. Effects of lead on growth, photosynthetic characteristics and production of reactive oxygen species of two freshwater green algae.

    PubMed

    Dao, Ly H T; Beardall, John

    2016-03-01

    In the natural environment, heavy metal contamination can occur as long-term pollution of sites or as pulses of pollutants from wastewater disposal. In this study two freshwater green algae, Chlorella sp. FleB1 and Scenedesmus YaA6, were isolated from lead-polluted water samples and the effects of 24 h vs 4 and 8 d exposure of cultures to lead on growth, photosynthetic physiology and production of reactive oxygen species (ROS) of these algae were investigated. In Chlorella sp. FleB1, there was agreement between lead impacts on chlorophyll content, photosynthesis and growth in most case. However, in Scenedesmus acutus YaA6 growth was inhibited at lower lead concentrations (0.03-0.87 × 10(-9) M), under which ROS, measured by 2',7' dichlorodihydrofluorescein diacetate fluorescence, were 4.5 fold higher than in controls but photosynthesis was not affected, implying that ROS had played a role in the growth inhibition that did not involve direct effects on photosynthesis. Effects of short-term (5 h, 24 h) vs long-term (4 d and 8 d) exposure to lead were also compared between the two algae. The results contribute to our understanding of the mechanisms of lead toxicity to algae. PMID:26774308

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

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

    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.

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

    SciTech Connect

    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

    1992-08-17

    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.

  17. Chlamydia muridarum infection of macrophages elicits bactericidal nitric oxide production via reactive oxygen species and cathepsin B.

    PubMed

    Rajaram, Krithika; Nelson, David E

    2015-08-01

    The ability of certain species of Chlamydia to inhibit the biogenesis of phagolysosomes permits their survival and replication within macrophages. The survival of macrophage-adapted chlamydiae correlates with the multiplicity of infection (MOI), and optimal chlamydial growth occurs in macrophages infected at an MOI of ?1. In this study, we examined the replicative capacity of Chlamydia muridarum in the RAW 264.7 murine macrophage cell line at different MOIs. C. muridarum productively infected these macrophages at low MOIs but yielded few viable elementary bodies (EBs) when macrophages were infected at a moderate (10) or high (100) MOI. While high MOIs caused cytotoxicity and irreversible host cell death, macrophages infected at a moderate MOI did not show signs of cytotoxicity until late in the infectious cycle. Inhibition of host protein synthesis rescued C. muridarum in macrophages infected at a moderate MOI, implying that chlamydial growth was blocked by activated defense mechanisms. Conditioned medium from these macrophages was antichlamydial and contained elevated levels of interleukin 1? (IL-1?), IL-6, IL-10, and beta interferon (IFN-?). Macrophage activation depended on Toll-like receptor 2 (TLR2) signaling, and cytokine production required live, transcriptionally active chlamydiae. A hydroxyl radical scavenger and inhibitors of inducible nitric oxide synthase (iNOS) and cathepsin B also reversed chlamydial killing. High levels of reactive oxygen species (ROS) led to an increase in cathepsin B activity, and pharmacological inhibition of ROS and cathepsin B reduced iNOS expression. Our data demonstrate that MOI-dependent TLR2 activation of macrophages results in iNOS induction via a novel ROS- and cathepsin-dependent mechanism to facilitate C. muridarum clearance. PMID:26015483

  18. Spatio-temporal relief from hypoxia and production of reactive oxygen species during bud burst in grapevine (Vitis vinifera)

    PubMed Central

    Meitha, Karlia; Konnerup, Dennis; Colmer, Timothy D.; Considine, John A.; Foyer, Christine H.; Considine, Michael J.

    2015-01-01

    Background and Aims Plants regulate cellular oxygen partial pressures (pO2), together with reduction/oxidation (redox) state in order to manage rapid developmental transitions such as bud burst after a period of quiescence. However, our understanding of pO2 regulation in complex meristematic organs such as buds is incomplete and, in particular, lacks spatial resolution. Methods The gradients in pO2 from the outer scales to the primary meristem complex were measured in grapevine (Vitis vinifera) buds, together with respiratory CO2 production rates and the accumulation of superoxide and hydrogen peroxide, from ecodormancy through the first 72?h preceding bud burst, triggered by the transition from low to ambient temperatures. Key Results Steep internal pO2 gradients were measured in dormant buds with values as low as 25?kPa found in the core of the bud prior to bud burst. Respiratory CO2 production rates increased soon after the transition from low to ambient temperatures and the bud tissues gradually became oxygenated in a patterned process. Within 3?h of the transition to ambient temperatures, superoxide accumulation was observed in the cambial meristem, co-localizing with lignified cellulose associated with pro-vascular tissues. Thereafter, superoxide accumulated in other areas subtending the apical meristem complex, in the absence of significant hydrogen peroxide accumulation, except in the cambial meristem. By 72?h, the internal pO2 gradient showed a biphasic profile, where the minimum pO2 was external to the core of the bud complex. Conclusions Spatial and temporal control of the tissue oxygen environment occurs within quiescent buds, and the transition from quiescence to bud burst is accompanied by a regulated relaxation of the hypoxic state and accumulation of reactive oxygen species within the developing cambium and vascular tissues of the heterotrophic grapevine buds. PMID:26337519

  19. A Novel Nontoxic Inhibitor of the Activation of NADPH Oxidase Reduces Reactive Oxygen Species Production in Mouse LungS⃞

    PubMed Central

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

    2013-01-01

    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

  20. Chlamydia muridarum Infection of Macrophages Elicits Bactericidal Nitric Oxide Production via Reactive Oxygen Species and Cathepsin B

    PubMed Central

    Rajaram, Krithika

    2015-01-01

    The ability of certain species of Chlamydia to inhibit the biogenesis of phagolysosomes permits their survival and replication within macrophages. The survival of macrophage-adapted chlamydiae correlates with the multiplicity of infection (MOI), and optimal chlamydial growth occurs in macrophages infected at an MOI of ≤1. In this study, we examined the replicative capacity of Chlamydia muridarum in the RAW 264.7 murine macrophage cell line at different MOIs. C. muridarum productively infected these macrophages at low MOIs but yielded few viable elementary bodies (EBs) when macrophages were infected at a moderate (10) or high (100) MOI. While high MOIs caused cytotoxicity and irreversible host cell death, macrophages infected at a moderate MOI did not show signs of cytotoxicity until late in the infectious cycle. Inhibition of host protein synthesis rescued C. muridarum in macrophages infected at a moderate MOI, implying that chlamydial growth was blocked by activated defense mechanisms. Conditioned medium from these macrophages was antichlamydial and contained elevated levels of interleukin 1β (IL-1β), IL-6, IL-10, and beta interferon (IFN-β). Macrophage activation depended on Toll-like receptor 2 (TLR2) signaling, and cytokine production required live, transcriptionally active chlamydiae. A hydroxyl radical scavenger and inhibitors of inducible nitric oxide synthase (iNOS) and cathepsin B also reversed chlamydial killing. High levels of reactive oxygen species (ROS) led to an increase in cathepsin B activity, and pharmacological inhibition of ROS and cathepsin B reduced iNOS expression. Our data demonstrate that MOI-dependent TLR2 activation of macrophages results in iNOS induction via a novel ROS- and cathepsin-dependent mechanism to facilitate C. muridarum clearance. PMID:26015483

  1. Instability of Succinate Dehydrogenase in SDHD Polymorphism Connects Reactive Oxygen Species Production to Nuclear and Mitochondrial Genomic Mutations in Yeast

    PubMed Central

    Chang, Ya-Lan; Hsieh, Meng-Hsun; Chang, Wei-Wen; Wang, Hurng-Yi; Lin, Mei-Chun; Wang, Cheng-Ping

    2015-01-01

    Abstract Aims: Mitochondrial succinate dehydrogenase (SDH) is an essential complex of the electron transport chain and tricarboxylic acid cycle. Mutations in the human SDH subunit D frequently lead to paraganglioma (PGL), but the mechanistic consequences of the majority of SDHD polymorphisms have yet to be unraveled. In addition to the originally discovered yeast SDHD subunit Sdh4, a conserved homolog, Shh4, has recently been identified in budding yeast. To assess the pathogenic significance of SDHD mutations in PGL patients, we performed functional studies in yeast. Results: SDHD protein expression was reduced in SDHD-related carotid body tumor tissues. A BLAST search of SDHD to the yeast protein database revealed a novel protein, Shh4, that may have a function similar to human SDHD and yeast Sdh4. The missense SDHD mutations identified in PGL patients were created in Sdh4 and Shh4, and, surprisingly, a severe respiratory incompetence and reduced expression of the mutant protein was observed in the sdh4Δ strain expressing shh4. Although shh4Δ cells showed no respiratory-deficient phenotypes, deletion of SHH4 in sdh4Δ cells further abolished mitochondrial function. Remarkably, sdh4Δ shh4Δ strains exhibited increased reactive oxygen species (ROS) production, nuclear DNA instability, mtDNA mutability, and decreased chronological lifespan. Innovation and Conclusion: SDHD mutations are associated with protein and nuclear and mitochondrial genomic instability and increase ROS production in our yeast model. These findings reinforce our understanding of the mechanisms underlying PGL tumorigenesis and point to the yeast Shh4 as a good model to investigate the possible pathogenic relevance of SDHD in PGL polymorphisms. Antioxid. Redox Signal. 22, 587–602. PMID:25328978

  2. MuRF1 activity is present in cardiac mitochondria and regulates reactive oxygen species production in vivo

    PubMed Central

    Mattox, Taylor A.; Young, Martin E.; Rubel, Carrie E.; Spaniel, Carolyn; Rodrguez, Jessica E.; Grevengoed, Trisha J.; Gautel, Mathias; Xu, Zhelong; Anderson, Ethan J.; Willis, Monte S.

    2014-01-01

    MuRF1 is a previously reported ubiquitin-ligase found in striated muscle that targets troponin I and myosin heavy chain for degradation. While MuRF1 has been reported to interact with mitochondrial substrates in yeast two-hybrid studies, no studies have identified MuRF1s role in regulating mitochondrial function to date. In the present study, we measured cardiac mitochondrial function from isolated permeabilized muscle fibers in previously phenotyped MuRF1 transgenic and MuRF1?/? mouse models to determine the role of MuRF1 in intermediate energy metabolism and ROS production. We identified a significant decrease in reactive oxygen species production in cardiac muscle fibers from MuRF1 transgenic mice with increased alpha-MHC driven MuRF1 expression. Increased MuRF1 expression in ex vivo and in vitro experiments revealed no alterations in the respiratory chain complex I and II function. Working perfusion experiments on MuRF1 transgenic hearts demonstrated significant changes in glucose or oleate oxidation; however, total oxygen consumption was decreased. This data provides evidence for MuRF1 as a novel regulator of cardiac ROS, offering another mechanism by which increased MuRF1 expression may be cardioprotective in ischemia reperfusion injury, in addition to its inhibition of apoptosis via proteasome-mediate degradation of c-Jun. The lack of mitochondrial function phenotype identified in MuRF1?/? hearts may be due to the overlapping interactions of MuRF1 and MuRF2 with energy regulating proteins found by yeast two-hybrid studies reported here, implying a duplicity in MuRF1 and MuRF2s regulation of mitochondrial function. PMID:24733503

  3. Reactive transport model of growth and methane production by high-temperature methanogens in hydrothermal regions of the subseafloor

    NASA Astrophysics Data System (ADS)

    Stewart, L. C.; Algar, C. K.; Topuo?lu, B. D.; Fortunato, C. S.; Larson, B. I.; Proskurowski, G. K.; Butterfield, D. A.; Vallino, J. J.; Huber, J. A.; Holden, J. F.

    2014-12-01

    Hydrogenotrophic methanogens are keystone high-temperature autotrophs in deep-sea hydrothermal vents and tracers of habitability and biogeochemical activity in the hydrothermally active subseafloor. At Axial Seamount, nearly all thermophilic methanogens are Methanothermococcus and Methanocaldococcus species, making this site amenable to modeling through pure culture laboratory experiments coupled with field studies. Based on field microcosm incubations with 1.2 mM, 20 ?M, or no hydrogen, the growth of methanogens at 55C and 80C is limited primarily by temperature and hydrogen availability, with ammonium amendment showing no consistent effect on total methane output. The Arrhenius constants for methane production by Methanocaldococcus jannaschii (optimum 82C) and Methanothermococcus thermolithotrophicus (optimum 65C) were determined in pure culture bottle experiments. The Monod constants for hydrogen concentration were measured by growing both organisms in a 2-liter chemostat at two dilution rates; 55C, 65C and 82C; and variable hydrogen concentrations. M. jannaschii showed higher ks and Vmax constants than M. thermolithotrophicus. In the field, hydrogen and methane concentrations in hydrothermal end-member and low-temperature diffuse fluids were measured, and the concentrations of methanogens that grow at 55C and 80C in diffuse fluids were determined using most-probable-number estimates. Methane concentration anomalies in diffuse fluids relative to end-member hydrothermal concentrations and methanogen cell concentrations are being used to constrain a 1-D reactive transport model using the laboratory-determined Arrhenius and Monod constants for methane production by these organisms. By varying flow path length and subseafloor cell concentrations in the model, our goal is to determine solutions for the potential depth of the subseafloor biosphere coupled with the amount of methanogenic biomass it contains.

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

    PubMed Central

    Weissman, Lior; Garty, Jacob; Hochman, Ayala

    2005-01-01

    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

  5. Elastic scattering and ? production in the Be9+Y89 system

    NASA Astrophysics Data System (ADS)

    Palshetkar, C. S.; Santra, S.; Shrivastava, A.; Chatterjee, A.; Pandit, S. K.; Ramachandran, K.; Parkar, V. V.; Nanal, V.; Jha, V.; Roy, B. J.; Kalias, S.

    2014-06-01

    Elastic scattering measurement for the Be9+Y89 system has been carried out at near-barrier energies with the aim of investigating the effect of breakup on the elastic channel. The energy dependence of the optical model potential for the system gives an indication of the breakup threshold anomaly (BTA) for the system. An overall repulsive real part of the dynamic polarization potential (DPP) generated due to continuum couplings using the ? +He5 cluster structure for Be9 is consistent with the BTA behavior observed for the system. In contrast, an attractive real part of the DPP, at all energies, is observed for similar calculations carried out using the Be8+n cluster structure. Coupling of the 1n transfer channel in addition to continuum couplings does not have a significant effect on the elastic scattering angular distributions. The experimental 1n transfer cross sections show better agreement with the corresponding values obtained using the Be8+n cluster structure calculations. Inclusive breakup-? cross sections are observed to form a large fraction of the reaction cross sections, especially at below-barrier energies, suggesting the dominance of the breakup channel at these energies. This also supports the BTA behavior observed for the system, reflected as the presence of a reaction channel and thus the persistence of the imaginary potential at below-barrier energies.

  6. COMMENT: Comments on the production of autoionizing states in the scattering of argon ions from a magnesium surface

    NASA Astrophysics Data System (ADS)

    Guillemot, L.; Maazouz, M.; Esaulov, V. A.

    1996-02-01

    This paper comments on the results of recent studies of 0953-8984/8/8/018/img1 scattering on Mg, as well as Al and Si, surfaces by Blum et al and Nixon et al. The strong excitation of 0953-8984/8/8/018/img2 states is reported in these works, especially for low (1 keV) collision energies. This result contradicts our earlier work and the work of other authors. We re-investigated 0953-8984/8/8/018/img1 scattering but did not find any evidence of 0953-8984/8/8/018/img4 state production. However, 0953-8984/8/8/018/img4 state production is observed in 0953-8984/8/8/018/img6 collisions and we conclude that a contamination of the 0953-8984/8/8/018/img1 beam with 0953-8984/8/8/018/img6 in the work of the above authors is responsible for their observations. We also comment on the identification of structures due to excited sputtered Mg.

  7. Electron scattering on the Hoyle state and carbon production in stars

    SciTech Connect

    Chernykh, M.; Neumann-Cosel, P. von; Richter, A.; Blok, H. P.; Feldmeier, H.; Neff, T.

    2009-01-28

    High-resolution inelastic electron scattering experiments were performed at the S-DALINAC for a precise determination of the partial pair width {gamma}{sub {pi}} of the second J{sup {pi}} = 0{sup +} state, the so-called Hoyle state, in {sup 12}C. Results for the monopole matrix element (directly related to {gamma}{sub {pi}}) from a nearly model-independent analysis based on an extrapolation of low-q data to zero momentum transfer are presented. Additionally, a Fourier-Bessel analysis of the transition form factor is discussed. The combined result of both methods leads to a pair width {gamma}{sub {pi}}62.2(10) {mu}eV.

  8. Barth Syndrome: From Mitochondrial Dysfunctions Associated with Aberrant Production of Reactive Oxygen Species to Pluripotent Stem Cell Studies.

    PubMed

    Saric, Ana; Andreau, Karine; Armand, Anne-Sophie; Mller, Ian M; Petit, Patrice X

    2015-01-01

    Mutations in the gene encoding the enzyme tafazzin, TAZ, cause Barth syndrome (BTHS). Individuals with this X-linked multisystem disorder present cardiomyopathy (CM) (often dilated), skeletal muscle weakness, neutropenia, growth retardation, and 3-methylglutaconic aciduria. Biopsies of the heart, liver and skeletal muscle of patients have revealed mitochondrial malformations and dysfunctions. It is the purpose of this review to summarize recent results of studies on various animal or cell models of Barth syndrome, which have characterized biochemically the strong cellular defects associated with TAZ mutations. Tafazzin is a mitochondrial phospholipidlysophospholipid transacylase that shuttles acyl groups between phospholipids and regulates the remodeling of cardiolipin (CL), a unique inner mitochondrial membrane phospholipid dimer consisting of two phosphatidyl residues linked by a glycerol bridge. After their biosynthesis, the acyl chains of CLs may be modified in remodeling processes involving up to three different enzymes. Their characteristic acyl chain composition depends on the function of tafazzin, although the enzyme itself surprisingly lacks acyl specificity. CLs are crucial for correct mitochondrial structure and function. In addition to their function in the basic mitochondrial function of ATP production, CLs play essential roles in cardiac function, apoptosis, autophagy, cell cycle regulation and Fe-S cluster biosynthesis. Recent developments in tafazzin research have provided strong insights into the link between mitochondrial dysfunction and the production of reactive oxygen species (ROS). An important tool has been the generation of BTHS-specific induced pluripotent stem cells (iPSCs) from BTHS patients. In a complementary approach, disease-specific mutations have been introduced into wild-type iPSC lines enabling direct comparison with isogenic controls. iPSC-derived cardiomyocytes were then characterized using biochemical and classical bioenergetic approaches. The cells are tested in a "heart-on-chip" assay to model the pathophysiology in vitro, to characterize the underlying mechanism of BTHS deriving from TAZ mutations, mitochondrial deficiencies and ROS production and leading to tissue defects, and to evaluate potential therapies with the use of mitochondrially targeted antioxidants. PMID:26834781

  9. Toxicity of nano-TiO2 on algae and the site of reactive oxygen species production.

    PubMed

    Li, Fengmin; Liang, Zhi; Zheng, Xiang; Zhao, Wei; Wu, Miao; Wang, Zhenyu

    2015-01-01

    Given the extensive use of nanomaterials, they may enter aquatic environments and harm the growth of algae, which are primary producers in an aquatic ecosystem. Thus, the balance of an aquatic ecosystem may be destroyed. In this study, Karenia brevis and Skeletonema costatum were exposed to nano-TiO2 (anatase, average particle size of 5-10 nm, specific surface area of 21010 m(2) g(-1)) to assess the effects of nano-TiO2 on algae. The findings of transmission electron microscopy-energy dispersive X-ray spectroscopy (TEM-EDX) and scanning electron microscopy (SEM) demonstrate aggregation of nano-TiO2 in the algal suspension. Nano-TiO2 was also found to be inside algal cells. The growth of the two species of algae was inhibited under nano-TiO2 exposure. The 72 h EC50 values of nano-TiO2 to K. brevis and S. costatum were 10.69 and 7.37 mg L(-1), respectively. TEM showed that the cell membrane of K. brevis was destroyed and its organelles were almost undistinguished under nano-TiO2 exposure. The malondialdehyde (MDA) contents of K. brevis and S. costatum significantly increased compared with those of the control (p<0.05). Meanwhile, superoxide dismutase (SOD) and catalase activities (CAT) of K. brevis and S. costatum changed in different ways. The reactive oxygen species (ROS) levels in both species were significantly higher than those of the control (p<0.05). The site of ROS production and accumulation in K. brevis and S. costatum under nano-TiO2 exposure was explored with the addition of inhibitors of different electron transfer chains. This study indicated that nano-TiO2 in algal suspensions inhibited the growth of K. brevis and S. costatum. This effect was attributed to oxidative stress caused by ROS production inside algal cells. The levels of anti-oxidative enzymes changed, which destroyed the balance between oxidation and anti-oxidation. Thus, algae were damaged by ROS accumulation, resulting in lipid oxidation and inhibited algae growth. The inhibitors of the electron transfer chain showed that the site of ROS production and accumulation in K. brevis cells was the chloroplast. PMID:25461740

  10. Barth Syndrome: From Mitochondrial Dysfunctions Associated with Aberrant Production of Reactive Oxygen Species to Pluripotent Stem Cell Studies

    PubMed Central

    Saric, Ana; Andreau, Karine; Armand, Anne-Sophie; Møller, Ian M.; Petit, Patrice X.

    2016-01-01

    Mutations in the gene encoding the enzyme tafazzin, TAZ, cause Barth syndrome (BTHS). Individuals with this X-linked multisystem disorder present cardiomyopathy (CM) (often dilated), skeletal muscle weakness, neutropenia, growth retardation, and 3-methylglutaconic aciduria. Biopsies of the heart, liver and skeletal muscle of patients have revealed mitochondrial malformations and dysfunctions. It is the purpose of this review to summarize recent results of studies on various animal or cell models of Barth syndrome, which have characterized biochemically the strong cellular defects associated with TAZ mutations. Tafazzin is a mitochondrial phospholipidlysophospholipid transacylase that shuttles acyl groups between phospholipids and regulates the remodeling of cardiolipin (CL), a unique inner mitochondrial membrane phospholipid dimer consisting of two phosphatidyl residues linked by a glycerol bridge. After their biosynthesis, the acyl chains of CLs may be modified in remodeling processes involving up to three different enzymes. Their characteristic acyl chain composition depends on the function of tafazzin, although the enzyme itself surprisingly lacks acyl specificity. CLs are crucial for correct mitochondrial structure and function. In addition to their function in the basic mitochondrial function of ATP production, CLs play essential roles in cardiac function, apoptosis, autophagy, cell cycle regulation and Fe-S cluster biosynthesis. Recent developments in tafazzin research have provided strong insights into the link between mitochondrial dysfunction and the production of reactive oxygen species (ROS). An important tool has been the generation of BTHS-specific induced pluripotent stem cells (iPSCs) from BTHS patients. In a complementary approach, disease-specific mutations have been introduced into wild-type iPSC lines enabling direct comparison with isogenic controls. iPSC-derived cardiomyocytes were then characterized using biochemical and classical bioenergetic approaches. The cells are tested in a “heart-on-chip” assay to model the pathophysiology in vitro, to characterize the underlying mechanism of BTHS deriving from TAZ mutations, mitochondrial deficiencies and ROS production and leading to tissue defects, and to evaluate potential therapies with the use of mitochondrially targeted antioxidants. PMID:26834781

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

    PubMed

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

    2014-02-01

    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

  12. Docosahexaenoic acid prevents paraquat-induced reactive oxygen species production in dopaminergic neurons via enhancement of glutathione homeostasis

    SciTech Connect

    Lee, Hyoung Jun; Han, Jeongsu; Jang, Yunseon; Kim, Soo Jeong; Park, Ji Hoon; Seo, Kang Sik; Jeong, Soyeon; Shin, Soyeon; Lim, Kyu; Heo, Jun Young; Kweon, Gi Ryang

    2015-01-30

    Highlights: • DHA prevents PQ-induced dopaminergic neuronal loss via decreasing of excessive ROS. • DHA increases GR and GCLm derivate GSH pool by enhancement of Nrf2 expression. • Protective mechanism is removal of PQ-induced ROS via DHA-dependent GSH pool. • DHA may be a good preventive strategy for Parkinson’s disease (PD) therapy. - Abstract: Omega-3 polyunsaturated fatty acid levels are reduced in the substantia nigra area in Parkinson’s disease patients and animal models, implicating docosahexaenoic acid (DHA) as a potential treatment for preventing Parkinson’s disease and suggesting the need for investigations into how DHA might protect against neurotoxin-induced dopaminergic neuron loss. The herbicide paraquat (PQ) induces dopaminergic neuron loss through the excessive production of reactive oxygen species (ROS). We found that treatment of dopaminergic SN4741 cells with PQ reduced cell viability in a dose-dependent manner, but pretreatment with DHA ameliorated the toxic effect of PQ. To determine the toxic mechanism of PQ, we measured intracellular ROS content in different organelles with specific dyes. As expected, all types of ROS were increased by PQ treatment, but DHA pretreatment selectively decreased cytosolic hydrogen peroxide content. Furthermore, DHA treatment-induced increases in glutathione reductase and glutamate cysteine ligase modifier subunit (GCLm) mRNA expression were positively correlated with glutathione (GSH) content. Consistent with this increase in GCLm mRNA levels, Western blot analysis revealed that DHA pretreatment increased nuclear factor-erythroid 2 related factor 2 (Nrf2) protein levels. These findings indicate that DHA prevents PQ-induced neuronal cell loss by enhancing Nrf2-regulated GSH homeostasis.

  13. Searching for and exploring double-parton scattering effects in four-jet production at the LHC

    NASA Astrophysics Data System (ADS)

    Maciu?a, Rafa?; Szczurek, Antoni

    2015-10-01

    We discuss four-jet production at the LHC. We calculate cross section for both single-parton scattering (SPS) using the ALPGEN code and for double-parton scattering (DPS) in leading-order collinear approach. Our results are compared with experimental data obtained recently by the CMS Collaboration. We show that the ALPGEN code relatively well describes distributions in transverse momenta and rapidity of each of the four jets ordered by their transverse momenta (leading, subleading, etc.). The SPS mechanism does not explain the distributions at large rapidity for the leading jet. The DPS mechanism improves the agreement with the experimental data in this corner of the phase space. In order to enhance the relative DPS contribution we propose to impose different cuts. The relative DPS contribution increases when decreasing the lower cut on the jet transverse momenta as well as when a low lower cut on the rapidity distance between the most remote jets is imposed. We predict very flat distribution in azimuthal angle between the most remote jets with low lower cuts on jets transverse momentum. We find phase-space corners where the DPS content is enhanced relatively to the SPS one.

  14. Rapid bioassay to measure early reactive oxygen species production in Arabidopsis leave tissue in response to living Pseudomonas syringae

    PubMed Central

    2014-01-01

    Background Arabidopsis thaliana and Pseudomonas syringae pathovar tomato (Pto) provide an excellent plant-bacteria model system to study innate immunity. During pattern-triggered immunity (PTI), cognate host receptors perceive pathogen-associated molecular patterns (PAMPs) as non-self molecules. Pto harbors many PAMPs; thus for experimental ease, many studies utilize single synthesized PAMPs such as flg22, a short protein peptide derived from Pseudomonas flagellin. Flg22 recognition by Arabidopsis Flagellin Sensing 2 (FLS2) initiates a plethora of signaling responses including rapid production of apoplastic reactive oxygen species (ROS). Assessing flg22-ROS has been instrumental in identifying novel PAMP-signaling components; but comparably little is known whether in Arabidopsis, ROS is produced in response to intact live Pto and whether this response can be used to dissect genetic requirements of the plant host and live bacterial pathogens in planta. Results Here, we report of a fast and robust bioassay to quantitatively assess early ROS in Arabidopsis leaves, a tissue commonly used for pathogen infection assays, in response to living bacterial Pto strains. We establish that live Pto elicits a transient and dose-dependent ROS that differed in timing of initiation, amplitude and duration compared to flg22-induced ROS. Our control experiments confirmed that the detected ROS was dependent on the presence of the bacterial cells. Utilizing Arabidopsis mutants previously shown to be defective in flg22-induced ROS, we demonstrate that ROS elicited by live Pto was fully or in part dependent on RbohD and BAK1, respectively. Because fls2 mutants did not produce any ROS, flagellin perception by FLS2 is the predominant recognition event in live Pto-elicited ROS in Arabidopsis leaves. Furthermore using different Pto strains, our in planta results indicate that early ROS production appeared to be independent of the Type III Secretion System. Conclusions We provide evidence and necessary control experiments demonstrating that in planta, this ROS bioassay can be utilized to rapidly screen different Arabidopsis mutant lines and ecotypes in combination with different bacterial strains to investigate the genetic requirements of a plant host and its pathogen. For future experiments, this robust bioassay can be easily extended beyond Arabidopsis-Pto to diverse plant-pathosystems including crop species and their respective microbial pathogens. PMID:24571722

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    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.

  16. 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)

    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

    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.

  17. 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)

    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

    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.

  18. Aging Enhances the Production of Reactive Oxygen Species and Bactericidal Activity in Peritoneal Macrophages by Upregulating Classical Activation Pathways

    SciTech Connect

    Smallwood, Heather S.; Lopez-Ferrer, Daniel; Squier, Thomas C.

    2011-10-07

    Maintenance of macrophages in their basal state and their rapid activation in response to pathogen detection are central to the innate immune system, acting to limit nonspecific oxidative damage and promote pathogen killing following infection. To identify possible age-related alterations in macrophage function, we have assayed the function of peritoneal macrophages from young (3−4 months) and aged (14−15 months) Balb/c mice. In agreement with prior suggestions, we observe age-dependent increases in the extent of recruitment of macrophages into the peritoneum, as well as ex vivo functional changes involving enhanced nitric oxide production under resting conditions that contribute to a reduction in the time needed for full activation of senescent macrophages following exposure to lipopolysaccharides (LPS). Further, we observe enhanced bactericidal activity following Salmonella uptake by macrophages isolated from aged Balb/c mice in comparison with those isolated from young animals. Pathways responsible for observed phenotypic changes were interrogated using tandem mass spectrometry, which identified age-dependent increases in levels of proteins linked to immune cell pathways under basal conditions and following LPS activation. Immune pathways upregulated in macrophages isolated from aged mice include proteins critical to the formation of the immunoproteasome. Detection of these latter proteins is dramatically enhanced following LPS exposure for macrophages isolated from aged animals; in comparison, the identification of immunoproteasome subunits is insensitive to LPS exposure for macrophages isolated from young animals. Consistent with observed global changes in the proteome, quantitative proteomic measurements indicate that there are age-dependent abundance changes involving specific proteins linked to immune cell function under basal conditions. LPS exposure selectively increases the levels of many proteins involved in immune cell function in aged Balb/c mice. Collectively, these results indicate that macrophages isolated from old mice are in a preactivated state that enhances their sensitivities to LPS exposure. The hyper-responsive activation of macrophages in aged animals may act to minimize infection by general bacterial threats that arise due to age-dependent declines in adaptive immunity. However, this hypersensitivity and the associated increase in the level of formation of reactive oxygen species are likely to contribute to observed age-dependent increases in the level of oxidative damage that underlie many diseases of the elderly.

  19. Mycobacterium tuberculosis epitope-specific interferon-g production in healthy Brazilians reactive and non-reactive to tuberculin skin test

    PubMed Central

    da Silva, Bosco Christiano Maciel; Grassi, Maria Fernanda Rios; Coutinho, Raimundo; Mascarenhas, Rita Elizabeth Moreira; Olavarria, Viviana Nilla; Coutinho-Borgo, Adriana; Kalil, Jorge; Cunha, Edecio; Fonseca, Simone Gonçalves

    2014-01-01

    The interferon (IFN)-γ response to peptides can be a useful diagnostic marker of Mycobacterium tuberculosis (MTB) latent infection. We identified promiscuous and potentially protective CD4+ T-cell epitopes from the most conserved regions of MTB antigenic proteins by scanning the MTB antigenic proteins GroEL2, phosphate-binding protein 1 precursor and 19 kDa antigen with the TEPITOPE algorithm. Seven peptide sequences predicted to bind to multiple human leukocyte antigen (HLA)-DR molecules were synthesised and tested with IFN-γ enzyme-linked immunospot (ELISPOT) assays using peripheral blood mononuclear cells (PBMCs) from 16 Mantoux tuberculin skin test (TST)-positive and 16 TST-negative healthy donors. Eighty-eight percent of TST-positive donors responded to at least one of the peptides, compared to 25% of TST-negative donors. Each individual peptide induced IFN-γ production by PBMCs from at least 31% of the TST-positive donors. The magnitude of the response against all peptides was 182 ± 230 x 106 IFN-γ spot forming cells (SFC) among TST-positive donors and 36 ± 62 x 106 SFC among TST-negative donors (p = 0.007). The response to GroEL2 (463-477) was only observed in the TST-positive group. This combination of novel MTB CD4 T-cell epitopes should be tested in a larger cohort of individuals with latent tuberculosis (TB) to evaluate its potential to diagnose latent TB and it may be included in ELISPOT-based IFN-γ assays to identify individuals with this condition. PMID:25494469

  20. Trans-3,4-dideoxyglucone-3-ene (trans-3,4-DGE), a most reactive glucose degradation product in freshly heat sterilized glucose solutions.

    PubMed

    Chen, Ke; Prabel, Jason; Dutton, Johanna; Gotoda, Masaharu; Asai, Yumi; Grobin, Adam

    2015-12-11

    In our study, one or more glucose degradation products (GDPs) in freshly heat sterilized dextrose 5% in water (D5W) were found to react with a drug candidate having a ?-keto amide group (Compound A) to form several drug related compounds with the same molecular weight. However the previously identified GDPs did not react with Compound A to produce the observed adducts, indicating that unidentified GDP(s) reacted with Compound A to form these adducts. Our investigation by reaction-directed fractionation of the reactive D5W with HPLC led to the identification of the reactive GDP, trans-3,4-dideoxyglucosone-3-ene (trans-3,4-DGE), responsible for producing these reaction products. The trans-3,4-DGE was identified from its derivatives of dinitrophenylhydrazine (DNPH) and acetoacetanilide and confirmed by (1) admixing Compound A with authentic trans-3,4-DGE to produce the identical impurities as admixing with freshly heat sterilized D5W, and (2) NMR analysis of the reactive fraction of glucose solutions. PMID:26546740

  1. Label-free surface-enhanced Raman scattering strategy for rapid detection of penicilloic acid in milk products.

    PubMed

    Qi, Meihui; Huang, Xiaoyan; Zhou, Yujie; Zhang, Liying; Jin, Yang; Peng, Yan; Jiang, Huijun; Du, Shuhu

    2016-04-15

    A label-free surface-enhanced Raman scattering (SERS) strategy based on silver-coated gold nanoparticles (Au@Ag NPs) was developed for rapid detection of penicilloic acid (PA) in milk products. It has been demonstrated that core size and shell thickness of Au@Ag NPs are two critical variants affecting enhancement of Raman signals by coupling of two plasma resonance absorption. The Au@Ag NPs with 26-nm core and 9-nm Ag shell exhibit excellent Raman enhancement, in particular, upon the formation of hot spots through NPs aggregation induced by interaction between target molecules and Au@Ag NPs. Compared to the early studies limited to laboratory settings, our analytical approach is simple (without sample pretreatment), less time-consuming (within ∼3 min) and inexpensive. The limit of detection of PA is 3.00 ppm, 3.00 ppm and 4.00 ppm in liquid milk, yogurt and milk powder, respectively. The label-free SERS technique offers a potential for the on-site monitoring of chemical contaminants in milk products. PMID:26617009

  2. Ultracold-neutron production and up-scattering in superfluid helium between 1.1 K and 2.4 K

    NASA Astrophysics Data System (ADS)

    Leung, K. K. H.; Ivanov, S.; Piegsa, F. M.; Simson, M.; Zimmer, O.

    2016-02-01

    Ultracold neutrons (UCNs) were produced in superfluid helium using the PF1B cold-neutron beam facility at the Institut Laue-Langevin. A 4-liter beryllium-coated converter volume with a mechanical valve and windowless stainless-steel extraction system were used to accumulate and guide UCNs to a detector at room temperature. At a converter temperature of 1.08 K the total storage time constant in the vessel was (20.3 ±1.2 )s and the number of UCNs counted after accumulated was 91 700 ±300 . From this, we derive a volumetric UCN production rate of (6.9 ±1.7 ) cm-3s-1 , which includes a correction for losses in the converter during UCN extraction caused by the short storage time, but not accounting for UCN transport and detection efficiencies. The up-scattering rate of UCNs caused by excitations in the superfluid was studied by scanning the temperature between 1.2 K and 2.4 K . Using the temperature-dependent UCN production rate calculated from inelastic neutron scattering data, the only UCN up-scattering process found to occur was from two-phonon scattering. Our analysis for T <1.95 K rules out the contributions from roton-phonon scattering to <29 % (95% C.I.) and from one-phonon absorption to <47 % (95% C.I.) of their predicted levels.

  3. Antiviral antibodies stimulate production of reactive oxygen species in cultured canine brain cells infected with canine distemper virus.

    PubMed

    Brge, T; Griot, C; Vandevelde, M; Peterhans, E

    1989-06-01

    Canine distemper is characterized mainly by respiratory, enteric, and nervous symptoms. Infection of the central nervous system results in demyelination, to which inflammation has been shown to contribute significantly. It has been proposed that macrophages play a major role as effector cells in this process. We report that cultured dog brain cells contain a population of macrophages capable of producing reactive oxygen species as measured by luminol-dependent chemiluminescence. In cultures infected with canine distemper virus, a burst of reactive oxygen is triggered by antiviral antibody. This response depends on the presence of viral antigens on the surfaces of infected cells and is mediated by the interaction of antigen-bound antibody with Fc receptors on the macrophages. Since there is no evidence in vitro or in vivo that oligodendrocytes, the cells forming myelin, are infected, our observation supports the hypothesis that "innocent bystander killing" is important in demyelination caused by canine distemper virus. Reactive oxygen species released from macrophages may contribute to destruction of myelin. PMID:2724413

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

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

    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.

  5. Production of isomers by neutron-induced inelastic scattering on 193Ir and influence of spin distribution in the pre-equilibrium process

    NASA Astrophysics Data System (ADS)

    Kawano, Toshihiko; Talou, Patrick; Chadwick, Mark B.

    2006-06-01

    We present calculations of the production cross-section of isomeric-state for 193Ir. The isomer was produced by neutron inelastic scattering, and several ?-ray production cross-sections were measured at LANSCE with the GEANIE detector. The total isomer production cross-section is then inferred by combining the experimental data with the GNASH statistical model calculations. The spin distribution is calculated with the Feshbach-Kerman-Koonin (FKK) quantum mechanical pre-equilibrium theory, and it is incorporated with the GNASH results. We found that the inclusion of FKK has a significant impact on the isomer production cross-sections at high energies.

  6. The essential oils from Zanthoxylum schinifolium pericarp induce apoptosis of HepG2 human hepatoma cells through increased production of reactive oxygen species.

    PubMed

    Paik, Soon-Young; Koh, Kyung-Hee; Beak, Sung-Mok; Paek, Seung-Hwan; Kim, Jung-Ae

    2005-05-01

    The volatile extract from dried pericarp of Zanthoxylum schinifolium that was obtained by simultaneous distillation with dichloromethane and water was composed of 29.9% geranyl acetate, 15.8% citronella, 15.4% sabinene and the minor volatile components included beta-myrcene, linalool, (-)-isopulegol, citronellyl acetate, 1,4-dimethyl pyrazole, alpha-terpinene, 3-methyl-6-(1-methylethyl)-2-cyclo-hexene-1-o1 and trans-geraniol. The volatile extract decreased the cell viability and induced apoptotic death in HepG2 human hepatoma cells in a concentration- and time-related manner. In addition, the volatile extract increased the production of reactive oxygen species in a dose-dependent manner. Pretreatment of the cells with Trolox, a well-known antioxidant, significantly suppressed the generation of reactive oxygen species and cell death induced by the extract. However, caspase-3 activity was not changed in the extract-treated cells, suggesting that the extract-induced apoptosis of HepG2 cells is caspase-3 independent. Furthermore, in nude mice inoculated with Huh-7 human hepatoma cells, the extract significantly inhibited tumor development. These results suggest that the volatile extract from Zanthoxylum schinifolium pericarpium is a good candidate for hepatocellular carcinoma (HCC) therapy and that reactive oxygen species are the key signaling molecules in the volatile extract-induced cell death in HepG2 cells. PMID:15863882

  7. Exendin-4 Suppresses Src Activation and Reactive Oxygen Species Production in Diabetic Goto-Kakizaki Rat Islets in an Epac-Dependent Manner

    PubMed Central

    Mukai, Eri; Fujimoto, Shimpei; Sato, Hiroki; Oneyama, Chitose; Kominato, Rieko; Sato, Yuichi; Sasaki, Mayumi; Nishi, Yuichi; Okada, Masato; Inagaki, Nobuya

    2011-01-01

    OBJECTIVE Reactive oxygen species (ROS) is one of most important factors in impaired metabolism secretion coupling in pancreatic ?-cells. We recently reported that elevated ROS production and impaired ATP production at high glucose in diabetic Goto-Kakizaki (GK) rat islets are effectively ameliorated by Src inhibition, suggesting that Src activity is upregulated. In the present study, we investigated whether the glucagon-like peptide-1 signal regulates Src activity and ameliorates endogenous ROS production and ATP production in GK islets using exendin-4. RESEARCH DESIGN AND METHODS Isolated islets from GK and control Wistar rats were used for immunoblotting analyses and measurements of ROS production and ATP content. Src activity was examined by immunoprecipitation of islet lysates followed by immunoblotting. ROS production was measured with a fluorescent probe using dispersed islet cells. RESULTS Exendin-4 significantly decreased phosphorylation of Src Tyr416, which indicates Src activation, in GK islets under 16.7 mmol/l glucose exposure. Glucose-induced ROS production (16.7 mmol/l) in GK islet cells was significantly decreased by coexposure of exendin-4 as well as PP2, a Src inhibitor. The Src kinasenegative mutant expression in GK islets significantly decreased ROS production induced by high glucose. Exendin-4, as well as PP2, significantly increased impaired ATP elevation by high glucose in GK islets. The decrease in ROS production by exendin-4 was not affected by H-89, a PKA inhibitor, and an Epac-specific cAMP analog (8CPT-2Me-cAMP) significantly decreased Src Tyr416 phosphorylation and ROS production. CONCLUSIONS Exendin-4 decreases endogenous ROS production and increases ATP production in diabetic GK rat islets through suppression of Src activation, dependently on Epac. PMID:20978090

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

    NASA Astrophysics Data System (ADS)

    Detyothin, Sukeewan

    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.

  9. Observation by flow sup 1 H NMR and dimerization kinetics and products of reactive ortho-quinodimethanes and benzocyclobutadiene

    SciTech Connect

    Fischer, D.

    1990-09-21

    The reactive o-quinodimethanes, 1,2-dimethylene-1,2-dihydronaphthalene (9) and o-xylylene (1) were observed by flow {sup 1}H NMR spectroscopy at room temperature. The {sup 1}H NMR spectrum of 9 was obtained in the absence of precursor and dimers. However, the {sup 1}H NMR spectrum of the more reactive 1, generated in a similar manner from (o-((trimethylsilyl)methyl)benzyl)trimethylammonium iodide (5.) could be obtained only in the presence of its stable (4 + 2) and (4 + 4) dimers. The dimerization kinetics of 3-methyl- (5{prime}), 3,6-dimethyl- (11), 3-isopropyl- (12), and 3,6-diisoproply-1,2-xylylene (13) in acetonitrile (CH{sub 3}CN) were studied by stopped-flow UV-visible spectroscopy. Fluoride ion induced 1,2-elimination from 2-elimination from 2-trimethylsilylbenzocyclobutenyl-1 mesylate (26) was used to generate the reactive molecule benzocyclobutadiene (1{prime}) in CD{sub 3}CN, which was observed by flow {sup 1}H NMR spectroscopy at room temperature. The {sup 1}H NMR spectrum (in CD{sub 3}CN) of 1,2-dimethylene-1,2-dihydrothiophene (1{double prime}), obtained by fluoride ion induced 1,4-elimination from 3-(trimethylammoniummethyl)-2-(trimethylsilylmethyl)thiophene iodine was observed by flow {sup 1}H NMR spectroscopy at room temperature. The dimerization rate of 1{double prime} in CH{sub 3}CN, generated in the same manner, was measured by UV-visible spectroscopy. 166 refs., 7 figs., 7 tabs.

  10. Diverse modes of reactivity of dialkyl azodicarboxylates with P(III) compounds: synthesis, structure, and reactivity of products other than the Morrison-Brunn-Huisgen intermediate in a Mitsunobu-type reaction.

    PubMed

    Satish Kumar, N; Praveen Kumar, K; Pavan Kumar, K V P; Kommana, Praveen; Vittal, Jagadese J; Kumara Swamy, K C

    2004-03-19

    The reactivity of diethyl azodicarboxylate (DEAD)/diisopropyl azodicarboxylate (DIAD) with P(III) compounds bearing oxygen or nitrogen substituents is explored. Compounds with structures quite different from that of Morrison-Brunn-Huisgen intermediate R'(3)P(+)N(CO(2)R)N(-)(CO(2)R) (1), observed in the Mitsunobu reaction, have been established by using X-ray crystallography and NMR spectroscopy. Thus reactions with X(6-t-Bu-4-Me-C(6)H(2)O)(2)P-NH-t-Bu [X = S (8), CH(2) (9)] or XP(mu-N-t-Bu)(2)P-NH-t-Bu [X = Cl (14) or NH-t-Bu (15)] and DEAD/DIAD lead to phosphinimine-carbamate-type of products X[6-t-Bu-4-Me-C(6)H(2)O](2)P[N-t-Bu][N(CO(2)R)NH(CO(2)R)] [X = S, R = Et (16); X = CH(2), R = Et (17); X = CH(2), R = i-Pr (18)] or XP(mu-N-t-Bu)(2)P(N-t-Bu)[N-(CO(2)-i-Pr)-N(H)(CO(2)-i-Pr) [X = Cl (19), NH-t-Bu (20)]. Treatment of 19 with 2,2,2-trifluoroethanol afforded the product [(CF(3)CH(2)O)P(mu-N-t-Bu)(2)P(+)(NH-t-Bu)[N(CO(2)-i-Pr)(HNCO(2)-i-Pr)

  11. Rayleigh Scattering.

    ERIC Educational Resources Information Center

    Young, Andrew T.

    1982-01-01

    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)

  12. Reactivity of vinca alkaloids during water chlorination processes: Identification of their disinfection by-products by high-resolution quadrupole-Orbitrap mass spectrometry.

    PubMed

    Negreira, Noelia; Regueiro, Jorge; Lpez de Alda, Miren; Barcel, Dami

    2016-02-15

    Concerns about the presence of anticancer drugs in the environment are rapidly increasing mainly due to their growing use in the developed countries and their known cytotoxic effects. Vinca alkaloids are widely used in cancer therapy; however, very scarce information is available on their occurrence, environmental fate and toxicological effects on aquatic organisms. Even less attention has been paid to their potential transformation products, which can exert higher toxicity than the parent compounds. Thus, in the present work, the reactivity of vincristine, vinblastine, vinorelbine and its metabolite 4-O-deacetyl vinorelbine during water chlorination processes has been investigated for the first time. Under the studied chlorination conditions, vincristine was fairly stable whereas vinblastine, vinorelbine and 4-O-deacetyl vinorelbine were quickly degraded. A total of sixty-five disinfection by-products were tentatively identified by ultra-high performance liquid chromatography coupled to high-resolution hybrid quadrupole-Orbitrap tandem mass spectrometry. Among them, twenty by-products corresponded to mono-chlorinated compounds, eight to di-chlorinated compounds and two to tri-chlorinated compounds, which may be of major environmental concern. Other disinfection by-products involved hydroxylation and oxidation reactions. Although the structures of these by-products could not be positively confirmed due to lack of commercial standards, their chemical formulas and product ions can be added to databases, which will allow their screening in future monitoring studies. PMID:26674693

  13. Oxidation of fatty acids is the source of increased mitochondrial reactive oxygen species production in kidney cortical tubules in early diabetes.

    PubMed

    Rosca, Mariana G; Vazquez, Edwin J; Chen, Qun; Kerner, Janos; Kern, Timothy S; Hoppel, Charles L

    2012-08-01

    Mitochondrial reactive oxygen species (ROS) cause kidney damage in diabetes. We investigated the source and site of ROS production by kidney cortical tubule mitochondria in streptozotocin-induced type 1 diabetes in rats. In diabetic mitochondria, the increased amounts and activities of selective fatty acid oxidation enzymes is associated with increased oxidative phosphorylation and net ROS production with fatty acid substrates (by 40% and 30%, respectively), whereas pyruvate oxidation is decreased and pyruvate-supported ROS production is unchanged. Oxidation of substrates that donate electrons at specific sites in the electron transport chain (ETC) is unchanged. The increased maximal production of ROS with fatty acid oxidation is not affected by limiting the electron flow from complex I into complex III. The maximal capacity of the ubiquinol oxidation site in complex III in generating ROS does not differ between the control and diabetic mitochondria. In conclusion, the mitochondrial ETC is neither the target nor the site of ROS production in kidney tubule mitochondria in short-term diabetes. Mitochondrial fatty acid oxidation is the source of the increased net ROS production, and the site of electron leakage is located proximal to coenzyme Q at the electron transfer flavoprotein that shuttles electrons from acyl-CoA dehydrogenases to coenzyme Q. PMID:22586586

  14. Oxidation of Fatty Acids Is the Source of Increased Mitochondrial Reactive Oxygen Species Production in Kidney Cortical Tubules in Early Diabetes

    PubMed Central

    Rosca, Mariana G.; Vazquez, Edwin J.; Chen, Qun; Kerner, Janos; Kern, Timothy S.; Hoppel, Charles L.

    2012-01-01

    Mitochondrial reactive oxygen species (ROS) cause kidney damage in diabetes. We investigated the source and site of ROS production by kidney cortical tubule mitochondria in streptozotocin-induced type 1 diabetes in rats. In diabetic mitochondria, the increased amounts and activities of selective fatty acid oxidation enzymes is associated with increased oxidative phosphorylation and net ROS production with fatty acid substrates (by 40% and 30%, respectively), whereas pyruvate oxidation is decreased and pyruvate-supported ROS production is unchanged. Oxidation of substrates that donate electrons at specific sites in the electron transport chain (ETC) is unchanged. The increased maximal production of ROS with fatty acid oxidation is not affected by limiting the electron flow from complex I into complex III. The maximal capacity of the ubiquinol oxidation site in complex III in generating ROS does not differ between the control and diabetic mitochondria. In conclusion, the mitochondrial ETC is neither the target nor the site of ROS production in kidney tubule mitochondria in short-term diabetes. Mitochondrial fatty acid oxidation is the source of the increased net ROS production, and the site of electron leakage is located proximal to coenzyme Q at the electron transfer flavoprotein that shuttles electrons from acyl-CoA dehydrogenases to coenzyme Q. PMID:22586586

  15. Increased potential for NAD(P)H-dependent reactive oxygen species production of hepatic subcellular fractions of fish species with in vivo exposure to contaminants.

    PubMed

    Livingstone, D R; Mitchelmore, C L; O'Hara, S C; Lemaire, P; Sturve, J; Frlin, L

    2000-01-01

    The present study investigated the proposed involvement of contaminant-stimulated reactive oxygen species (ROS) production in disease processes in fish. NAD(P)H-dependent ROS production of subcellular fractions was determined by the iron/EDTA-mediated oxidation of 2-keto-4-methiolbutyric acid. Hepatic cytosolic NADPH-dependent and microsomal NAD(P)H-dependent ROS production were increased 51-160% (P < 0.05) in rainbow trout (Oncorhynchus mykiss) 15 weeks after a single i.p. injection of polychlorobiphenyl (PCB) (100 mg Clophen A50 kg-1 wet wt.). Hepatic microsomal NADH-dependent ROS production was 114% higher in perch (Perca fluviatilis) from PCB-contaminated Lake Jrnsjn compared to clean Lake Vnern, Sweden. Hepatic mitochondrial NADH-dependent, cytosolic NADH-dependent and microsomal NADPH-dependent ROS production were variously elevated up to 160% in flounder (Platichthys flesus) at various sites along two pollution transects near to the ports of Rotterdam and Amsterdam, Netherlands. Overall the data indicate increased potential for ROS production in liver of fish exposed to field pollution, and support the hypothesis of oxidative stress as a mechanism of contaminant-mediated disease in fish. PMID:11460751

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

    PubMed

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

    2014-10-15

    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

  17. Plastid Genome Instability Leads to Reactive Oxygen Species Production and Plastid-to-Nucleus Retrograde Signaling in Arabidopsis1[C][W][OPEN

    PubMed Central

    Lepage, tienne; Zampini, ric; Brisson, Normand

    2013-01-01

    The plastid genome is highly conserved among plant species, suggesting that alterations of its structure would have dramatic impacts on plant fitness. Nevertheless, little is known about the direct consequences of plastid genome instability. Recently, it was reported that the plastid Whirly proteins WHY1 and WHY3 and a specialized type-I polymerase, POLIB, act as safeguards against plastid genome instability in Arabidopsis (Arabidopsis thaliana). In this study, we use ciprofloxacin, an organelle double-strand break-inducing agent, and the why1why3polIb-1 variegated mutant to evaluate the impact of generalized plastid DNA instability. First, we show that in why1why3polIb-1 and ciprofloxacin-treated plants, plastid genome instability is associated with increased reactive oxygen species production. Then, using different light regimens, we show that the elevated reactive oxygen species production correlates with the appearance of a yellow-variegated phenotype in the why1why3polIb-1 population. This redox imbalance also correlates to modifications of nuclear gene expression patterns, which in turn leads to acclimation to high light. Taken together, these results indicate that plastid genome instability induces an oxidative burst that favors, through nuclear genetic reprogramming, adaptation to subsequent oxidative stresses. PMID:23969600

  18. Effect of Danofloxacin on Reactive Oxygen Species Production, Lipid Peroxidation and Antioxidant Enzyme Activities in Kidney Tubular Epithelial Cell Line, LLC-PK1.

    PubMed

    Yu, Chun-Hong; Liu, Zhao-Ying; Sun, Lei-Sheng; Li, Yu-Juan; Zhang, Da-Sheng; Pan, Ren-Tao; Sun, Zhi-Liang

    2013-12-01

    The purpose of this study was to investigate the possibility that oxidative stress was involved in danofloxacin-induced toxicity in renal tubular cells epithelial cell line (LLC-PK1). Confluent LLC-PK1 cells were incubated with various concentrations of danofloxacin. The extent of oxidative damage was assessed by measuring the reactive oxygen species (ROS) level, lipid peroxidation, cell apoptosis and antioxidative enzyme activities. Danofloxacin induced a concentration-dependent increase in the ROS production, not even cytotoxic conditions. Similarly, danofloxacin caused an about 4 times increase in the level of thiobarbituric acid reactive substances at the concentration of 400 μM for 24 hr, but it did not induce cytotoxicity and apoptosis. Antioxidant enzymes activities, such as superoxide dismutase (SOD) and catalase (CAT), were increased after treatment with 100, 200 and 400 μM of danofloxacin for 24 hr. The activity of glutathione peroxidase (GPX) was significantly decreased in a concentration-dependent manner. In addition, ROS production, lipid peroxidation and GPX decline were inhibited by additional glutathione and N-acetyl cysteine. These data suggested that danofloxacin could not induce oxidative stress in LLC-PK1 cells at the concentration (≤400 μM) for 24 hr. The increase levels of ROS and lipid peroxidation could be partly abated by the increase activities of SOD and CAT. PMID:23855763

  19. C60-Fullerene monomalonate adducts selectively inactivate neuronal nitric oxide synthase by uncoupling the formation of reactive oxygen intermediates from nitric oxide production.

    PubMed

    Wolff, D J; Mialkowski, K; Richardson, C F; Wilson, S R

    2001-01-01

    C(60)-Fullerene monomalonate adducts inactivate selectively the neuronal nitric oxide synthase isoform in a manner completely preventable by the concurrent presence of superoxide dismutase and catalase. This inactivation is time-, fullerene concentration-, and turnover-dependent and is not reversible by dilution. The di(carboxypropan-3-ol)methano-[60]-fullerene (diol adduct) has no effect on NADPH consumption by nNOS as measured in the absence of arginine substrate, but dramatically increases NADPH consumption in the presence of arginine. This fullerene-enhanced NADPH consumption is linked to oxygen as electron acceptor and is accompanied by the increased production of hydrogen peroxide. These effects of fullerene monomalonate adducts are unique to the nNOS isoform and are not observed using either the iNOS or the eNOS isoform. The inhibitory effects of fullerene monomalonate adducts are unaltered and insurmountable by increased concentrations of arginine, tetrahydrobiopterin, or calmodulin. These observations indicate that fullerene monomalonate adducts uncouple in the presence of arginine the formation of reactive oxygen intermediates from NO production by nNOS. These reactive oxygen intermediates dissociate from the enzyme and, acting from solution, inactivate NOS NO forming activity. PMID:11141054

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

    SciTech Connect

    Shertzer, Howard G. . E-mail: shertzhg@ucmail.uc.edu; Genter, Mary Beth; Shen, Dongxiao; Nebert, Daniel W.; Chen, Ying; Dalton, Timothy P.

    2006-12-15

    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.

  1. IgE-mediated allergic reactions to fruit gums and investigation of cross-reactivity between gelatine and modified gelatine-containing products.

    PubMed

    Wahl, R; Kleinhans, D

    1989-01-01

    A 32-year-old female reacted with a contact urticaria syndrome after eating 'gummy bears' (fruit gums). The reaction began in the oral mucosa and led to treatment on an inpatient basis. RAST measurements with allergen discs produced with gelatine and gelatine-containing products (among them 'gummy bears') demonstrated the presence of IgE antibodies in the serum of this patient. Proteins with molecular weights in the range of 40-120 kD were identified as the allergens in gelatine by using Western blot analysis. RAST inhibition showed cross-reactivity between gelatine, gelatine-containing products and the modified gelatine used in some plasma substitutes. Allergic reactions towards coloured fruit candies and 'gummy bears' may result from an IgE-mediated hypersensitivity towards gelatine. The long-known anaphylactoid reactions towards gelatine-containing plasma substitutes may, at least in part, be of an allergic nature. PMID:2702514

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

    PubMed

    Brouard, M; Chadwick, H; Gordon, S D S; Hornung, B; Nichols, B; Kłos, J; Aoiz, F J; Stolte, S

    2014-10-28

    Fully quantum state selected and resolved inelastic scattering of NO(X) by krypton has been investigated. Initial Λ-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. PMID:25362298

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

    SciTech Connect

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

    2014-10-28

    Fully quantum state selected and resolved inelastic scattering of NO(X) by krypton has been investigated. Initial Λ-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{sup −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.

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

    SciTech Connect

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

    2010-01-01

    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.

  5. Transitional reactive oxygen species (ROS) production in fertilized egg embryos of devil stinger (Inimicus japonicus), a marine fish species.

    PubMed

    Kim, Daekyung; Naruse, Sayaka; Kadomura, Kazushi; Nakashima, Takuji; Jiang, Zedong; Yamasaki, Yasuhiro; Yamaguchi, Kenichi; Oda, Tatsuya

    2012-01-01

    A time-course analysis of reactive oxygen species (ROS) generation in fertilized eggs of the devil stinger (Inimicus japonicus) from 0 h post-fertilization (hpf) to the early larval stage indicated that the ROS level was highest in the 22 hpf embryo, and declined thereafter. Phorbol myristate acetate (PMA) had no effect on ROS generation by the 22 hpf embryo, whereas PMA significantly increased larval ROS generation, suggesting that the ROS generation mechanisms of the 22 hpf embryo and larva are different at least in terms of PMA-responsiveness. Our results suggest the presence of a specific ROS generation system in devil stinger embryo which can be transitionally activated during embryogenesis. PMID:22878181

  6. AMPK is Involved in Mediation of Erythropoietin Influence on Metabolic Activity and Reactive Oxygen Species Production in White Adipocytes

    PubMed Central

    Wang, Li; Di, Lijun; Noguchi, Constance Tom

    2014-01-01

    Erythropoietin, discovered for its indispensable role during erythropoiesis, has been used in the therapy for selected red blood cell disorders in erythropoietin-deficient patients. The biological activities of erythropoietin have been found to extend to non-erythroid tissues due to the expression of erythropoietin receptor. We previously demonstrated that erythropoietin promotes metabolic activity and white adipocytes browning to increase mitochondrial function and energy expenditure via peroxisome proliferator-activated receptor alpha and Sirtuin1. Here we report that AMP-activated protein kinase was activated by erythropoietin possibly via Ca2+/calmodulin-dependent protein kinase kinase in adipocytes as well as in white adipose tissue from diet induced obese mice. Erythropoietin increased cellular Nicotinamide adenine dinucleotide via increased AMP-activated protein kinase activity, possibly leading to Sirtuin1 activation. AMP-activated protein kinase knock down reduced erythropoietin mediated increase in cellular oxidative function including the increased oxygen consumption rate, fatty acid utilization and induction of key metabolic genes. Under hypoxia, adipocytes were found to generate more reactive oxygen species, and erythropoietin reduced the reactive oxygen species and increased antioxidant gene expression, suggesting that erythropoietin may provide protection from oxidative stress in adipocytes. Erythropoietin also reversed increased nicotinamide adenine dinucleotide by hypoxia via increased AMP-activated protein kinase. Additionally, AMP-activated protein kinase is found to be involved in erythropoietin stimulated increase in oxygen consumption rate, fatty acid oxidation and mitochondrial gene expression. AMP-activated protein kinase knock down impaired erythropoietin stimulated increases in antioxidant gene expression. Collectively, our findings identify the AMP-activated protein kinase involvement in erythropoietin signaling in regulating adipocyte cellular redox status and metabolic activity. PMID:24953559

  7. Impulsive model for reactive collisions

    NASA Technical Reports Server (NTRS)

    Marron, M. T.; Bernstein, R. B.

    1972-01-01

    A simple classical mechanical model of the reactive scattering of a structureless atom A and a quasi-diatomic BC is developed which takes full advantage of energy, linear and angular momentum conservation relations but introduces a minimum of further assumptions. These are as follows: (1) the vibrational degree of freedom of the reactant (BC) and product (AB) molecules is suppressed, so the change in vibrational energy is simply a parameter; (2) straight-line trajectories are assumed outside of a reaction shell; (3) within this zone, momentum transfer occurs impulsively (essentially instantaneously) following mass transfer; (4) the impulse, which may be either positive or negative, is directed along the BC axis, which may, however, assume all orientations with respect to the incident relative velocity. The model yields differential and total cross sections and product rotational energy distributions for a given collision exoergicity Q, or for any known distribution over Q. Numerical results are presented for several prototype reactions whose dynamics have been well-studied.

  8. Induction of phosphatidylinositol 3-kinase-mediated endocytosis by salt stress leads to intracellular production of reactive oxygen species and salt tolerance.

    PubMed

    Leshem, Yehoram; Seri, Lior; Levine, Alex

    2007-07-01

    Salt imposes immediate problems for plant cells, such as osmotic stress, impaired ion homeostasis and sodium toxicity, followed by a secondary oxidative stress caused by generation of reactive oxygen species (ROS). Here, we analyzed the production of ROS during salt stress. We show that salt stress triggered plasma membrane internalization, resulting in the production of ROS within endosomes. The intracellular ROS were produced by NADPH oxidase in response to the ionic but not the osmotic stress. Both endocytosis and ROS production were suppressed in phosphatidylinositol (PtdIns) 3-kinase (PI3K) mutants, PI3K being a key regulator of vesicle trafficking in animals and plants, and by wortmannin, which is a specific inhibitor of PI3K and PI4K. Endocytosis and the production of ROS were rescued by supplementation of seedlings with exogenous PtdIns 3-phosphate (PtdIns3P), less with PtdIns4P, but not with PtdIns(4,5)P(2). Surprisingly, despite reduced oxidative stress, the mutants and the wortmannin-treated plants exhibited a phenotype overly sensitive to salt, as also resulted from treatment with diphenyleneiodonium, a suicide inhibitor of NADPH oxidase, suggesting a positive role for ROS in salt tolerance. In summary, our results show that salt stress responses, such as increased plasma membrane endocytosis and the intracellular production of ROS, are coordinated by phospholipid-regulated signaling pathways, and suggest that ROS act in the signal transduction of the salt tolerance response. PMID:17521408

  9. Measurement of “pretzelosity” asymmetry of charged pion production in semi-inclusive deep inelastic scattering on a polarized He3 target

    DOE PAGESBeta

    Zhang, Y.; Qian, X.; Allada, K.; Dutta, C.; Huang, J.; Katich, J.; Wang, Y.; Aniol, K.; Annand, J. R. M.; Averett, T.; et al

    2014-11-24

    An experiment to measure single-spin asymmetries in semi-inclusive production of charged pions in deep-inelastic scattering on a transversely polarized ³He target was performed at Jefferson Lab in the kinematic region of 0.16 < x < 0.35 and 1.4 < Q² < 2.7 GeV². Our results show that both π± on 3He and on neutron pretzelosity asymmetries are consistent with zero within experimental uncertainties.

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

    SciTech Connect

    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.

    1995-02-27

    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.

  11. Azoxystrobin-induced excessive reactive oxygen species (ROS) production and inhibition of photosynthesis in the unicellular green algae Chlorella vulgaris.

    PubMed

    Liu, Lei; Zhu, Bin; Wang, Gao-Xue

    2015-05-01

    This study investigated the short-term toxicity of azoxystrobin (AZ), one of strobilurins used as an effective fungicidal agent to control the Asian soybean rust, on aquatic unicellular algae Chlorella vulgaris. The median percentile inhibition concentration (IC₅₀) of AZ for C. vulgaris was found to be 510 μg L(-1). We showed that the algal cells were obviously depressed or shrunk in 300 and 600 μg L(-1) AZ treatments by using the electron microscopy. Furthermore, 19, 75, and 300 μg L(-1) AZ treatments decreased the soluble protein content and chlorophyll concentrations in C. vulgaris and altered the energy-photosynthesis-related mRNA expression levels in 48- and 96-h exposure periods. Simultaneously, our results showed that AZ could increase the total antioxidant capacity (T-AOC) level and compromise superoxide dismutase (SOD), peroxidase (POD), glutathione S transferase (GST), glutathione peroxidase (GPx) activities, and glutathione (GSH) content. These situations might render C. vulgaris more vulnerable to oxidative damage. Overall, the present study indicated that AZ might be toxic to the growth of C. vulgaris, affect energy-photosynthesis-related mRNA expressions, and induce reactive oxygen species (ROS) overproduction in C. vulgaris. PMID:25672875

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

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

    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.

  13. Groundwater dynamics in wetland soils control the production and transfer mechanisms of dissolved reactive phosphorus in an agricultural landscape

    NASA Astrophysics Data System (ADS)

    Dupas, Rémi; Gu, Sen; Gruau, Gérard; Gascuel-Odoux, Chantal

    2015-04-01

    Because of its high sorption affinity on soils solid phase, mitigation options to reduce diffuse P transfer usually focus on trapping particulate P forms delivered via surface flowpaths. Therefore, vegetated buffer zones placed between croplands and watercourses have been promoted worldwide, sometimes in wetland areas. To investigate the risk of such P trapping riparian wetlands (RWs) releasing dissolved P to rivers, we monitored molybdate reactive P (MRP) in the free soil solution of two RWs in an intensively farmed catchment. Two main mechanisms causing MRP release were identified in light of the geochemical and hydrological conditions in the RWs, controlled by groundwater dynamics. First, soil rewetting after the dry summer was associated with the presence of a pool of mobile P, limited in size. Its mobilization started under conditions of water saturation caused by groundwater uprise in RW organo-mineral soil horizons. Second, the establishment of anoxic conditions in the end of the winter caused reductive solubilization of Fe oxide-hydroxide, along with release of P. Comparison between sites revealed that the first MRP release occurred only in a RW with P enriched soils, whereas the second was recorded even in a RW with a low soil P status. Seasonal variations in MRP concentrations in the stream were synchronized with those in RW soils. Hence, enriched and/or periodically anoxic RWs can act as a key component of the P transfer continuum in agricultural landscapes by converting particulate P from croplands into MRP released to rivers.

  14. Effect of Apigenin on Leishmania amazonensis Is Associated with Reactive Oxygen Species Production Followed by Mitochondrial Dysfunction.

    PubMed

    Fonseca-Silva, Fernanda; Canto-Cavalheiro, Marilene M; Menna-Barreto, Rubem F S; Almeida-Amaral, Elmo E

    2015-04-24

    Leishmaniasis is an important neglected disease caused by protozoa of the genus Leishmania that affects more than 12 million people worldwide. Leishmaniasis treatment requires the administration of toxic and poorly tolerated drugs, and parasite resistance greatly reduces the efficacy of conventional medications. Apigenin (1), a naturally occurring plant flavone, has a wide range of reported biological effects. In this study, antileishmanial activity of 1 in vitro was investigated, and its mechanism of action against Leishmania amazonensis promastigotes was described. Treatment with 1 for 24 h resulted in concentration-dependent inhibition of cellular proliferation (IC50 = 23.7 ?M) and increased reactive oxygen species (ROS) generation. Glutathione and N-acetyl-l-cysteine protected L. amazonensis from the effects of 1 and reduced ROS levels after the treatment. By contrast, oxidized glutathione did not reduce the levels of ROS caused by 1 by not preventing the proliferation inhibition. Apigenin 1 also induced an extensive swelling in parasite mitochondria, leading to an alteration of the mitochondrial membrane potential, rupture of the trans-Golgi network, and cytoplasmic vacuolization. These results demonstrate the leishmanicidal effect of 1 and suggest the involvement of ROS leading to mitochondrial collapse as part of the mechanism of action. PMID:25768915

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

    PubMed Central

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

    2013-01-01

    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

  16. Production and utilization of detyrosinated tubulin in developing Artemia larvae: evidence for a tubulin-reactive carboxypeptidase.

    PubMed

    Xiang, H; MacRae, T H

    1995-01-01

    The reversible, enzymatically driven removal and readdition of its carboxy-terminal tyrosine are major posttranslational modifications of alpha-tubulin. To study these processes isoform-specific antibodies were produced and subsequently used to characterize tyrosinated and detyrosinated tubulin in the brine shrimp, Artemia. Tyrosinated tubulin existed in relatively constant amounts on western blots of cell-free protein extracts from Artemia at all developmental stages examined, whereas detyrosinated tubulin was present after 20-24 h of postgastrula growth. In agreement with the blots, the detyrosinated isoform was observed in immunofluorescently stained larvae after 24 h of incubation, appearing first in structures of a transient nature, namely spindles and midbodies. The elongated muscle cells encircling the gut and the epithelium bordering the gut lumen were stained extensively with antibody to detyrosinated tubulin. Detyrosination was accompanied by the appearance of a tubulin-reactive carboxypeptidase, which used both nonpolymerized and polymerized tubulin as substrate. The enzyme bound to microtubules very poorly, if at all, under conditions used in this work. Several inhibitors of carboxypeptidase A had no effect on the carboxypeptidase from Artemia and revealed similarities between this enzyme and others thought to be tubulin specific. The use of inhibitors also indicated that the carboxypeptidase from Artemia recognized aspects of tubulin structure in addition to the carboxy-terminal tyrosine. Our results support the idea that detyrosinated tubulin appears in microtubules of varying stability, and they demonstrate that Artemia possess a carboxypeptidase with the potential to detyrosinate tubulin during growth of larvae. PMID:8714688

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

    PubMed

    Maynard, Scott; Keijzers, Guido; Gram, Martin; Desler, Claus; Bendix, Laila; Budtz-Jørgensen, Esben; Molbo, Drude; Croteau, Deborah L; Osler, Merete; Stevnsner, Tinna; Rasmussen, Lene Juel; Dela, Flemming; Avlund, Kirsten; Bohr, Vilhelm A

    2013-11-01

    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

  18. Understanding composite explosive energetics: 4. Reactive flow modeling of aluminum reaction kinetics in PETN and TNT using normalized product equation of state

    SciTech Connect

    Tao, W.C.; Tarver, C.M.; Kury, J.W.; Lee, C.G.; Ornellas, D.L.

    1993-07-01

    Using Fabry-Perot interferometry techniques, we have determined the early time rate of energy release from detonating PETN and TNT explosives filled with 5 to 20 wt % of either 5 {mu}m or 18 {mu}m spherical aluminum with the detonation products, and calculate the extent of reaction at 1--3 {mu}s after the detonation. All of the metal in PETN formulations filled with 5 wt % and 10 wt % of either 5 {mu}m or 18 {mu}m aluminum reacted within 1.5 {mu}s, resulting in an increase of 18--22% in energy compared to pure PETN. For TNT formulations, between 5 to 10 wt % aluminum reacts completely with the same timeframe. A reactive flow hydrodynamic code model based on the Zeldovich-von Neumann-Doring (ZND) description of the reaction zone and subsequent reaction product expansion (Taylor wave) is used to address the reaction rate of the aluminum particles with detonation product gases. The detonation product JWL equation of state is derived from that of pure PETN using a parametric normalization methodology.

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

    PubMed Central

    2010-01-01

    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

  20. Winery by-products: extraction optimization, phenolic composition and cytotoxic evaluation to act as a new source of scavenging of reactive oxygen species.

    PubMed

    Melo, Priscilla Siqueira; Massarioli, Adna Prado; Denny, Carina; dos Santos, Luciana Ferracini; Franchin, Marcelo; Pereira, Giuliano Elias; Vieira, Thais Maria Ferreira de Souza; Rosalen, Pedro Luiz; de Alencar, Severino Matias

    2015-08-15

    Nearly 20 million tons of winery by-products, with many biological activities, are discarded each year in the world. The extraction of bioactive compounds from Chenin Blanc, Petit Verdot, and Syrah grape by-products, produced in the semi-arid region in Brazil, was optimized by a Central Composite Rotatable Design. The phenolic compounds profile, antioxidant capacity against synthetic free radicals (DPPH and ABTS), reactive oxygen species (ROS; peroxyl radical, superoxide radical, hypochlorous acid), cytotoxicity assay (MTT) and quantification of TNF-? production in RAW 264.7 cells were conducted. Gallic acid, syringic acid, procyanidins B1 and B2, catechin, epicatechin, epicatechin gallate, quercetin 3-?-d-glucoside, delfinidin 3-glucoside, peonidin 3-O-glucoside, and malvidin 3-glucoside were the main phenolic compounds identified. In general, rachis showed higher antioxidant capacity than pomace extract, especially for Chenin Blanc. All extracts showed low cytotoxicity against RAW 264.7 cells and Petit Verdot pomace suppressed TNF-? liberation in vitro. Therefore, these winery by-products can be considered good sources of bioactive compounds, with great potential for application in the food and pharmaceutical industries. PMID:25794735

  1. Inhibitors of succinate: quinone reductase/Complex II regulate production of mitochondrial reactive oxygen species and protect normal cells from ischemic damage but induce specific cancer cell death.

    PubMed

    Ralph, Stephen J; Moreno-Snchez, Rafael; Neuzil, Jiri; Rodrguez-Enrquez, Sara

    2011-11-01

    Succinate:quinone reductase (SQR) of Complex II occupies a unique central point in the mitochondrial respiratory system as a major source of electrons driving reactive oxygen species (ROS) production. It is an ideal pharmaceutical target for modulating ROS levels in normal cells to prevent oxidative stress-induced damage or alternatively,increase ROS in cancer cells, inducing cell death.The value of drugs like diazoxide to prevent ROS production,protecting normal cells, whereas vitamin E analogues promote ROS in cancer cells to kill them is highlighted. As pharmaceuticals these agents may prevent degenerative disease and their modes of action are presently being fully explored. The evidence that SDH/Complex II is tightly coupled to the NADH/NAD+ ratio in all cells,impacted by the available supplies of Krebs cycle intermediates as essential NAD-linked substrates, and the NAD+-dependent regulation of SDH/Complex II are reviewed, as are links to the NAD+-dependent dehydrogenases, Complex I and the E3 dihiydrolipoamide dehydrogenase to produce ROS. This review collates and discusses diverse sources of information relating to ROS production in different biological systems, focussing on evidence for SQR as the main source of ROS production in mitochondria, particularly its relevance to protection from oxidative stress and to the mitochondrial-targeted anti cancer drugs (mitocans) as novel cancer therapies [corrected]. PMID:21863476

  2. Role of Ca2+ in activation of reactive oxygen species production in polymorphonuclear leukocytes during tumour growth in rats.

    PubMed

    Pustovidko, A; Potselueva, M; Kochegarov, A; Evtodienko, Y

    2007-01-01

    The role of Ca(2+) ions in PMA-induced generation of reactive oxygen species (ROS) by polymorphonuclear leukocytes (PMNL) was studied during Zajdela hepatoma growth in the peritoneal cavity of rats. In PMNL from control healthy animals, a manifold Ca(2+)-induced enhancement of ROS generation and its significant reduction in the presence of Ca(2+) binding agent (BAPTA-AM) were observed. In contrast, ROS generation by PMNL from tumour-carrying animals dramatically increased in Ca(2+)-free medium, being practically insensitive to the agents, which can increase or decrease intracellular Ca(2+) levels. Free cytosolic Ca(2+) ([Ca(2+)](i)) in control PMNL was found to be relatively low ( approximately 250 nmol/L), rising slowly after Ca(2+) addition and further to two-fold in the presence of Ca(2+) and ionomycin in the incubating medium. Tumour growth in animals was accompanied with a significant [Ca(2+)](i) elevation. In Ca(2+)-free medium, [Ca(2+)](i) elevation was up to 480 nmol/L in tPMNL with the additions of Ca(+) and ionomycin as well as EGTA and ionomycin being able to increase [Ca(2+)](i) to 700-900 nmol/L onward. It was concluded that a higher Ca(2+) permeability of the plasma membrane and higher Ca(2+) accumulation in intracellular pools of PMNL was developed at the advanced stages of malignant disease. These results indicate the primed state of circulating PMNL and the independence of PMA-induced ROS generation at intra- and extracellular Ca(2+) levels at the advanced stages of tumour growth in animals. PMID:17262735

  3. The chlorinated AHR ligand 3,3?,4,4?,5-pentachlorobiphenyl (PCB126) promotes reactive oxygen species (ROS) production during embryonic development in the killifish (Fundulus heteroclitus)

    USGS Publications Warehouse

    Arzuaga, Xabier; Wassenberg, Deena; Giulio, Richard D.; Elskus, Adria

    2006-01-01

    Exposure to dioxin-like chemicals that activate the aryl hydrocarbon receptor (AHR) can result in increased cellular and tissue production of reactive oxygen species (ROS). Little is known of these effects during early fish development. We used the fish model,Fundulus heteroclitus, to determine if the AHR ligand and pro-oxidant 3,3?,4,4?,5-pentachlorobiphenyl (PCB126) can increase ROS production during killifish development, and to test a novel method for measuring ROS non-invasively in a living organism. The superoxide-sensitive fluorescent dye, dihydroethidium (DHE), was used to detect in ovo ROS production microscopically in developing killifish exposed to PCB126 or vehicle. Both in ovo CYP1A activity (ethoxyresorufin-o-deethylase, EROD) and in ovo ROS were induced by PCB126. In ovo CYP1A activity was inducible by PCB126 concentrations as low as 0.003nM, with maximal induction occurring at 0.3nM PCB126. These PCB126 concentrations also significantly increased in ovo ROS production in embryonic liver, ROS being detectable as early as 5 days post-fertilization. These data demonstrate that the pro-oxidant and CYP1A inducer, PCB126, increases both CYP1A activity and ROS production in developing killifish embryos. The superoxide detection assay (SoDA) described in this paper provides a semi-quantitative, easily measured, early indicator of altered ROS production that can be used in conjunction with simultaneous in ovo measurements of CYP1A activity and embryo development to explore functional relationships among biochemical, physiological and developmental responses to AHR ligands.

  4. Amyloid β oligomers induce interleukin-1β production in primary microglia in a cathepsin B- and reactive oxygen species-dependent manner

    SciTech Connect

    Taneo, Jun; Adachi, Takumi; Yoshida, Aiko; Takayasu, Kunio; Takahara, Kazuhiko; Inaba, Kayo

    2015-03-13

    Amyloid β (Aβ) peptide, a causative agent of Alzheimer's disease, forms two types of aggregates: oligomers and fibrils. These aggregates induce inflammatory responses, such as interleukin-1β (IL-1β) production by microglia, which are macrophage-like cells located in the brain. In this study, we examined the effect of the two forms of Aβ aggregates on IL-1β production in mouse primary microglia. We prepared Aβ oligomer and fibril from Aβ (1–42) peptide in vitro. We analyzed the characteristics of these oligomers and fibrils by electrophoresis and atomic force microscopy. Interestingly, Aβ oligomers but not Aβ monomers or fibrils induced robust IL-1β production in the presence of lipopolysaccharide. Moreover, Aβ oligomers induced endo/phagolysosome rupture, which released cathepsin B into the cytoplasm. Aβ oligomer-induced IL-1β production was inhibited not only by the cathepsin B inhibitor CA-074-Me but also by the reactive oxygen species (ROS) inhibitor N-acetylcysteine. Random chemical crosslinking abolished the ability of the oligomers to induce IL-1β. Thus, multimerization and fibrillization causes Aβ oligomers to lose the ability to induce IL-1β. These results indicate that Aβ oligomers, but not fibrils, induce IL-1β production in primary microglia in a cathepsin B- and ROS-dependent manner. - Highlights: • We prepared amyloid β (Aβ) fibrils with minimum contamination of Aβ oligomers. • Primary microglia (MG) produced IL-1β in response to Aβ oligomers, but not fibrils. • Only Aβ oligomers induced leakage of cathepsin B from endo/phagolysosomes. • IL-1β production in response to Aβ oligomers depended on both cathepsin B and ROS. • Crosslinking reduced the ability of the Aβ oligomers to induce IL-1β from MG.

  5. Optimization of reactive simulated moving bed systems with modulation of feed concentration for production of glycol ether ester.

    PubMed

    Agrawal, Gaurav; Oh, Jungmin; Sreedhar, Balamurali; Tie, Shan; Donaldson, Megan E; Frank, Timothy C; Schultz, Alfred K; Bommarius, Andreas S; Kawajiri, Yoshiaki

    2014-09-19

    In this article, we extend the simulated moving bed reactor (SMBR) mode of operation to the production of propylene glycol methyl ether acetate (DOWANOL™ PMA glycol ether) through the esterification of 1-methoxy-2-propanol (DOWANOL™ PM glycol ether) and acetic acid using AMBERLYST™ 15 as a catalyst and adsorbent. In addition, for the first time, we integrate the concept of modulation of the feed concentration (ModiCon) to SMBR operation. The performance of the conventional (constant feed) and ModiCon operation modes of SMBR are analyzed and compared. The SMBR processes are designed using a model based on a multi-objective optimization approach, where a transport dispersive model with a linear driving force for the adsorption rate has been used for modeling the SMBR system. The adsorption equilibrium and kinetics parameters are estimated from the batch and single column injection experiments by the inverse method. The multiple objectives are to maximize the production rate of DOWANOL™ PMA glycol ether, maximize the conversion of the esterification reaction and minimize the consumption of DOWANOL™ PM glycol ether which also acts as the desorbent in the chromatographic separation. It is shown that ModiCon achieves a higher productivity by 12-36% over the conventional operation with higher product purity and recovery. PMID:25127692

  6. 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

    Kenzom, T; Srivastava, P; Mishra, S

    2014-12-01

    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

  7. 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 Central

    Kenzom, T.; Srivastava, P.

    2014-01-01

    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

  8. Phenylethynyl terminated reactive oligomer

    NASA Technical Reports Server (NTRS)

    Bryant, Robert G. (Inventor); Jensen, Brian J. (Inventor); Hergenrother, Paul M. (Inventor)

    1995-01-01

    A composition of matter having the general structure: ##STR1## (wherein X is F, Cl, or NO.sub.2, and Y is CO, SO.sub.2 or C(CF.sub.3).sub.2) is employed to terminate a nucleophilic reagent, resulting in the exclusive production of phenylethynyl terminated reactive oligomers which display unique thermal characteristics. A reactive diluent having the general structure: ##STR2## (wherein R is any aliphatic or aromatic moiety) is employed to decrease the melt viscosity of a phenylethynyl terminated reactive oligomer and to subsequently react therewith to provide a thermosetting material of enhanced density. These materials have features which make them attractive candidates for use as composite matrices and adhesives.

  9. Stimulation of reactive oxygen species production and cytotoxicity in human neutrophils in vitro and after oral administration of a polyenzyme preparation.

    PubMed

    Zavadova, E; Desser, L; Mohr, T

    1995-01-01

    Polymorphonuclear neutrophils (PMN) can be primed for enhanced release of reactive oxygen species (ROS) by exposure to cytokines and biological response modifiers. ROS are considered to possess tumoricidal activity. The polyenzyme preparation Wobenzym (WE) contains pancreatin, papain, bromelain trypsin and chymotrypsin and is used in adjuvant tumor therapy. We investigated killing of WE-exposed PMN against tumor cells and analyzed WE influence on ROS production in a chemiluminescence assay in PMN in vitro and in vivo. Depending on dose WE stimulates the cytotoxic capacity of PMN in vitro against tumor cells (50 micrograms/ml:p < 0.01). Exposure of PMN to Wobenzym caused a time-dependent significant (p < 0.02) increase in release of ROS. Similarly, oral administration of Wobenzym to healthy volunteers (n = 28) resulted in significant increases (p < 0.01) in ROS production, depending on dose (peak with 20 tablets) and time (peak 4 hours after Wobenzym administration). In contrast, ROS production was not elevated in the PMN of healthy volunteers receiving placebo (n = 8) or no treatment (n = 16). These findings point to an immunomodulatory capacity of WE in adjuvant tumor therapy. PMID:7663574

  10. Integration of pharmacokinetic and NRF2 system biology models to describe reactive oxygen species production and subsequent glutathione depletion in liver microfluidic biochips after flutamide exposure.

    PubMed

    Leclerc, Eric; Hamon, Jeremy; Legendre, Audrey; Bois, Frederic Y

    2014-10-01

    We present a systems biology analysis of rat primary hepatocytes response after exposure to 10 ?M and 100 ?M flutamide in liver microfluidic biochips. We coupled an in vitro pharmacokinetic (PK) model of flutamide to a system biology model of its reactive oxygen species (ROS) production and scavenging by the Nrf2 regulated glutathione production. The PK model was calibrated using data on flutamide kinetics, hydroxyflutamide and glutathione conjugates formation in microfluidic conditions. The parameters of Nrf2-related gene activities and the subsequent glutathione depletion were calibrated using microarray data from our microfluidic experiments and literature information. Following a 10 ?M flutamide exposure, the model predicted a recovery time to baseline levels of glutathione (GSH) and ROS in agreement with our experimental observations. At 100 ?M, the model predicted that metabolism saturation led to an important accumulation of flutamide in cells, a high ROS production and complete GSH depletion. The high levels of ROS predicted were consistent with the necrotic switch observed by transcriptomics, and the high cell mortality we had experimentally observed. The model predicted a transition between recoverable GSH depletion and deep GSH depletion at about 12.5 ?M of flutamide (single perfusion exposure). Our work shows that in vitro biochip experiments can provide supporting information for complex in silico modeling including data from extra cellular and intra cellular levels. We believe that this approach can be an efficient strategy for a global integrated methodology in predictive toxicology. PMID:24929096

  11. Protection of hypoglycemia-induced neuronal death by ?-hydroxybutyrate involves the preservation of energy levels and decreased production of reactive oxygen species.

    PubMed

    Julio-Amilpas, Alberto; Montiel, Teresa; Soto-Tinoco, Eva; Gernimo-Olvera, Cristian; Massieu, Lourdes

    2015-05-01

    Glucose is the main energy substrate in brain but in certain circumstances such as prolonged fasting and the suckling period alternative substrates can be used such as the ketone bodies (KB), beta-hydroxybutyrate (BHB), and acetoacetate. It has been shown that KB prevent neuronal death induced during energy limiting conditions and excitotoxicity. The protective effect of KB has been mainly attributed to the improvement of mitochondrial function. In the present study, we have investigated the protective effect of D-BHB against neuronal death induced by severe noncoma hypoglycemia in the rat in vivo and by glucose deprivation (GD) in cortical cultures. Results show that systemic administration of D-BHB reduces reactive oxygen species (ROS) production in distinct cortical areas and subregions of the hippocampus and efficiently prevents neuronal death in the cortex of hypoglycemic animals. In vitro results show that D-BHB stimulates ATP production and reduces ROS levels, while the nonphysiologic isomer of BHB, L-BHB, has no effect on energy production but reduces ROS levels. Data suggest that protection by BHB, not only results from its metabolic action but is also related to its capability to reduce ROS, rendering this KB as a suitable candidate for the treatment of ischemic and traumatic injury. PMID:25649993

  12. Teaching the fundamentals of electron transfer reactions in mitochondria and the production and detection of reactive oxygen species

    PubMed Central

    Mailloux, Ryan J.

    2015-01-01

    Mitochondria fulfill a number of biological functions which inherently depend on ATP and O2−•/H2O2 production. Both ATP and O2−•/H2O2 are generated by electron transfer reactions. ATP is the product of oxidative phosphorylation whereas O2−• is generated by singlet electron reduction of di-oxygen (O2). O2−• is then rapidly dismutated by superoxide dismutase (SOD) producing H2O2. O2−•/H2O2 were once viewed as unfortunately by-products of aerobic respiration. This characterization is fitting considering over production of O2−•/H2O2 by mitochondria is associated with range of pathological conditions and aging. However, O2−•/H2O2 are only dangerous in large quantities. If produced in a controlled fashion and maintained at a low concentration, cells can benefit greatly from the redox properties of O2−•/H2O2. Indeed, low rates of O2−•/H2O2 production are required for intrinsic mitochondrial signaling (e.g. modulation of mitochondrial processes) and communication with the rest of the cell. O2−•/H2O2 levels are kept in check by anti-oxidant defense systems that sequester O2−•/H2O2 with extreme efficiency. Given the importance of O2−•/H2O2 in cellular function, it is imperative to consider how mitochondria produce O2−•/H2O2 and how O2−•/H2O2 genesis is regulated in conjunction with fluctuations in nutritional and redox states. Here, I discuss the fundamentals of electron transfer reactions in mitochondria and emerging knowledge on the 11 potential sources of mitochondrial O2−•/H2O2 in tandem with their significance in contributing to overall O2−•/H2O2 emission in health and disease. The potential for classifying these different sites in isopotential groups, which is essentially defined by the redox properties of electron donator involved in O2−•/H2O2 production, as originally suggested by Brand and colleagues is also surveyed in detail. In addition, redox signaling mechanisms that control O2−•/H2O2 genesis from these sites are discussed. Finally, the current methodologies utilized for measuring O2−•/H2O2 in isolated mitochondria, cell culture and in vivo are reviewed. PMID:25744690

  13. Teaching the fundamentals of electron transfer reactions in mitochondria and the production and detection of reactive oxygen species.

    PubMed

    Mailloux, Ryan J

    2015-01-01

    Mitochondria fulfill a number of biological functions which inherently depend on ATP and O2(-)/H2O2 production. Both ATP and O2(-)/H2O2 are generated by electron transfer reactions. ATP is the product of oxidative phosphorylation whereas O2(-) is generated by singlet electron reduction of di-oxygen (O2). O2(-) is then rapidly dismutated by superoxide dismutase (SOD) producing H2O2. O2(-)/H2O2 were once viewed as unfortunately by-products of aerobic respiration. This characterization is fitting considering over production of O2(-)/H2O2 by mitochondria is associated with range of pathological conditions and aging. However, O2(-)/H2O2 are only dangerous in large quantities. If produced in a controlled fashion and maintained at a low concentration, cells can benefit greatly from the redox properties of O2(-)/H2O2. Indeed, low rates of O2(-)/H2O2 production are required for intrinsic mitochondrial signaling (e.g. modulation of mitochondrial processes) and communication with the rest of the cell. O2(-)/H2O2 levels are kept in check by anti-oxidant defense systems that sequester O2(-)/H2O2 with extreme efficiency. Given the importance of O2(-)/H2O2 in cellular function, it is imperative to consider how mitochondria produce O2(-)/H2O2 and how O2(-)/H2O2 genesis is regulated in conjunction with fluctuations in nutritional and redox states. Here, I discuss the fundamentals of electron transfer reactions in mitochondria and emerging knowledge on the 11 potential sources of mitochondrial O2(-)/H2O2 in tandem with their significance in contributing to overall O2(-)/H2O2 emission in health and disease. The potential for classifying these different sites in isopotential groups, which is essentially defined by the redox properties of electron donator involved in O2(-)/H2O2 production, as originally suggested by Brand and colleagues is also surveyed in detail. In addition, redox signaling mechanisms that control O2(-)/H2O2 genesis from these sites are discussed. Finally, the current methodologies utilized for measuring O2(-)/H2O2 in isolated mitochondria, cell culture and in vivo are reviewed. PMID:25744690

  14. Shear-Induced Reactive Gelation.

    PubMed

    Brand, Bastian; Morbidelli, Massimo; Soos, Miroslav

    2015-11-24

    In this work, we describe a method for the production of porous polymer materials in the form of particles characterized by narrow pore size distribution using the principle of shear-induced reactive gelation. Poly(styrene-co-divinylbenzene) primary particles with diameter ranging from 80 to 200 nm are used as building blocks, which are assembled into fractal-like clusters when exposed to high shear rates generated in a microchannel. It was found that independent of the primary particle size, it is possible to modulate the internal structure of formed fractal-like aggregates having fractal dimension ranging from 2.4 to 2.7 by varying the residence time in the microchannel. Thermally induced postpolymerization was used to increase the mechanical resilience of such formed clusters. Primary particle interpenetration was observed by SEM and confirmed by light scattering resulting in an increase of fractal dimension. Nitrogen sorption measurements and mercury porosimetry confirmed formation of a porous material with surface area ranging from 20 to 40 m(2)/g characterized by porosity of 70% and narrow pore size distribution with an average diameter around 700 nm without the presence of any micropores. The strong perfusive character of the synthesized material was confirmed by the existence of a plateau of the height equivalent to a theoretical plate measured at high reduced velocities using a chromatographic column packed with the synthesized microclusters. PMID:26488233

  15. D-Galacturonic Acid: A Highly Reactive Compound in Nonenzymatic Browning. 2. Formation of Amino-Specific Degradation Products.

    PubMed

    Wegener, Steffen; Bornik, Maria-Anna; Kroh, Lothar W

    2015-07-22

    Thermal treatment of aqueous solutions of D-galacturonic acid and L-alanine at pH 3, 5, and 8 led to rapid and more intensive nonenzymatic browning reactions compared to similar solutions of other uronic acids and to Maillard reactions of reducing sugars. The hemiacetal ring structures of uronic acids had a high impact on browning behavior and reaction pathways. Besides reductic acid (1,2-dihydroxy-2-cyclopenten-1-one), 4,5-dihydroxy-2-cyclopenten-1-one (DHCP), furan-2-carboxaldehyde, and norfuraneol (4-hydroxy-5-methyl-3-(2H)-furanone) could be detected as typical products of nonenzymatic uronic acid browning reactions. 2-(2-Formyl-1H-pyrrole-1-yl)propanoic acid (FPA) and 1-(1-carboxyethyl)-3-hydroxypyridin-1-ium (HPA) were identified as specific reaction products of uronic acids with amine participation like l-alanine. In contrast, the structurally related D-galacturonic acid methyl ester showed less browning activity and degradation under equal reaction conditions. Pectin-specific degradation products such as 5-formyl-2-furanoic acid and 2-furanoic acid were found but could not be verified for d-galacturonic acid monomers alone. PMID:26111613

  16. DNAs from Brucella strains activate efficiently murine immune system with production of cytokines, reactive oxygen and nitrogen species.

    PubMed

    Tavakoli, Zahra; Ardestani, Sussan K; Lashkarbolouki, Taghi; Kariminia, Amina; Zahraei Salehi, Taghi; Tavassoli, Nasser

    2009-09-01

    Brucellosis is an infectious disease with high impact on innate immune responses which is induced partly by its DNA. In the present study the potential differences of wild type and patients isolates versus attenuated vaccine strains in terms of cytokines, ROS and NO induction on murine splenocytes and peritoneal macrophages were investigated. This panel varied in base composition and included DNA from B. abortus, B. melitensis, B.abortus strain S19 and melitensis strain Rev1, as attenuated live vaccine. Also we included Escherichia coli DNA, calf thymus DNA (a mammalian DNA), as controls. These DNA were evaluated for their ability to stimulate IL-12, TNF-alpha, IL-10, IFN-gamma and ROS production from spleenocytes as well as NO production from peritoneal macrophages. Spleen cells were cultured in 24 well at a concentration of 106 cells/ ml with subsequent addition of 10 microg/ml of Brucella or Ecoli DNAs. These cultures were incubated at 37 degrees C with 5% CO2 for 5 days. Supernatants were harvested and cytokines, ROS and NOx were evaluated. It was observed that TNF-alpha was induced in days 1,3,5 by all Brucella strains DNAs and E. coli DNA, IL-10 only was induced in day 1, IFN- gamma was induced only in day 5 and IL-12 not induced. ROS and NOx were produced by all strains; however, we observed higher production of NOx which were stimulated by DNA of B. melitensis. PMID:20124603

  17. Production of reactive oxygen species in decoupled, Ca(2+)-depleted PSII and their use in assigning a function to chloride on both sides of PSII.

    PubMed

    Semin, Boris K; Davletshina, Lira N; Timofeev, Kirill N; Ivanov, Il'ya I; Rubin, Andrei B; Seibert, Michael

    2013-11-01

    Extraction of Ca(2+) from the oxygen-evolving complex of photosystem II (PSII) in the absence of a chelator inhibits O2 evolution without significant inhibition of the light-dependent reduction of the exogenous electron acceptor, 2,6-dichlorophenolindophenol (DCPIP) on the reducing side of PSII. The phenomenon is known as "the decoupling effect" (Semin et al. Photosynth Res 98:235-249, 2008). Extraction of Cl(-) from Ca(2+)-depleted membranes (PSII[-Ca]) suppresses the reduction of DCPIP. In the current study we investigated the nature of the oxidized substrate and the nature of the product(s) of the substrate oxidation. After elimination of all other possible donors, water was identified as the substrate. Generation of reactive oxygen species HO, H2O2, and O 2 (·-) , as possible products of water oxidation in PSII(-Ca) membranes was examined. During the investigation of O 2 (·-) production in PSII(-Ca) samples, we found that (i) O 2 (·-) is formed on the acceptor side of PSII due to the reduction of O2; (ii) depletion of Cl(-) does not inhibit water oxidation, but (iii) Cl(-) depletion does decrease the efficiency of the reduction of exogenous electron acceptors. In the absence of Cl(-) under aerobic conditions, electron transport is diverted from reducing exogenous acceptors to reducing O2, thereby increasing the rate of O 2 (·-) generation. From these observations we conclude that the product of water oxidation is H2O2 and that Cl(-) anions are not involved in the oxidation of water to H2O2 in decoupled PSII(-Ca) membranes. These results also indicate that Cl(-) anions are not directly involved in water oxidation by the Mn cluster in the native PSII membranes, but possibly provide access for H2O molecules to the Mn4CaO5 cluster and/or facilitate the release of H(+) ions into the lumenal space. PMID:23794169

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

    PubMed Central

    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

    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. PMID:25422756

  19. Antiplatelet Effect of Catechol Is Related to Inhibition of Cyclooxygenase, Reactive Oxygen Species, ERK/p38 Signaling and Thromboxane A2 Production

    PubMed Central

    Wang, Tong-Mei; Lin, Bor-Ru; Yeung, Sin-Yuet; Yeh, Chien-Yang; Cheng, Ru-Hsiu; Jeng, Jiiang-Huei

    2014-01-01

    Catechol (benzenediol) is present in plant-derived products, such as vegetables, fruits, coffee, tea, wine, areca nut and cigarette smoke. Because platelet dysfunction is a risk factor of cardiovascular diseases, including stroke, atherosclerosis and myocardial infarction, the purpose of this study was to evaluate the anti-platelet and anti-inflammatory effect of catechol and its mechanisms. The effects of catechol on cyclooxygenase (COX) activity, arachidonic acid (AA)-induced aggregation, thromboxane B2 (TXB2) production, lactate dehydrogenase (LDH) release, reactive oxygen species (ROS) production and extracellular signal-regulated kinase (ERK)/p38 phosphorylation were determined in rabbit platelets. In addition, its effect on IL-1?-induced prostaglandin E2 (PGE2) production by fibroblasts was determined. The ex vivo effect of catechol on platelet aggregation was also measured. Catechol (5-25 M) suppressed AA-induced platelet aggregation and inhibited TXB2 production at concentrations of 0.55 M; however, it showed little cytotoxicity and did not alter U46619-induced platelet aggregation. Catechol (1050 M) suppressed COX-1 activity by 2944% and COX-2 activity by 2950%. It also inhibited IL-1?-induced PGE2 production, but not COX-2 expression of fibroblasts. Moreover, catechol (110 M) attenuated AA-induced ROS production in platelets and phorbol myristate acetate (PMA)-induced ROS production in human polymorphonuclear leukocytes. Exposure of platelets to catechol decreased AA-induced ERK and p38 phosphorylation. Finally, intravenous administration of catechol (2.55 mole/mouse) attenuated ex vivo AA-induced platelet aggregation. These results suggest that catechol exhibited anti-platelet and anti-inflammatory effects, which were mediated by inhibition of COX, ROS and TXA2 production as well as ERK/p38 phosphorylation. The anti-platelet effect of catechol was confirmed by ex vivo analysis. Exposure to catechol may affect platelet function and thus cardiovascular health. PMID:25122505

  20. Production of reactive sintered nickel aluminide. Fifth quarterly technical progress report, February 22, 1993--May 22, 1993

    SciTech Connect

    Cooper, R.M.

    1993-06-01

    Effort over the past 3 months was directed at increasing manufacturing capacity (ball milling) and improving product quality. Orders for the powder have increased, mainly for plasma spray powders. NiAl is an excellent coat between a metal and a ceramic, and its use instead of cobalt should extending operating range for carbide tools. The feather phase in the sintered Ni{sub 3}Al was identified to be a Ni-rich phase nucleated on the grain boundaries with 10 wt % Al composition. The ductile to brittle temperature of powder extruded NiAl was found to be between 500 and 600 C, and shows a 50% elongation at 600 C.

  1. Generalized analytical solution of multispecies reactive transport involving a wide range of boundary, initial, and production conditions

    NASA Astrophysics Data System (ADS)

    Chen, Jui-Sheng; Liang, Ching-Ping

    2013-04-01

    Transport processes of some contaminants such as radionuclide, chlorinated solvent, nitrogen may undergo a series of either first-order or pseudo first-order sequential reaction kinetics. When more mobile, toxic, and/or persistent daughter products of these decaying contaminants formed, we will concern about the potentially greater down-gradient plume extent and higher concentration levels of these target species besides the parent species. The single-species analytical solution does not permit to evaluate transport behavior of daughter species of the decaying contaminants. The analytical solution for multispecies transport equations with first-order sequential reactions will be a useful tool for the simultaneous evaluation of the fate and transport of the parent and daughter species of the decaying contaminants. The analytical solutions for multispecies transport equations in literature are mostly limited to one-dimensional transport systems with boundary source. Accordingly, this study attempts to present an explicit analytical solution for simulating multi-species transport involving a wide range of boundary, initial, and production conditions. The derived analytical solution has greater applications for evaluation of concentration distribution of arbitrary target species of the long-chain decaying contaminants.

  2. Reactive oxygen species (ROS) induced cytokine production and cytotoxicity of PAMAM dendrimers in J774A.1 cells

    SciTech Connect

    Naha, Pratap C.; Davoren, Maria; Lyng, Fiona M.; Byrne, Hugh J.

    2010-07-15

    The immunotoxicity of three generations of polyamidoamine (PAMAM) dendrimers (G-4, G-5 and G-6) was evaluated in mouse macrophage cells in vitro. Using the Alamar blue and MTT assays, a generation dependent cytotoxicity of the PAMAM dendrimers was found whereby G-6 > G-5 > G-4. The toxic response of the PAMAM dendrimers correlated well with the number of surface primary amino groups, with increasing number resulting in an increase in toxic response. An assessment of intracellular ROS generation by the PAMAM dendrimers was performed by measuring the increased fluorescence as a result of intracellular oxidation of Carboxy H{sub 2}DCFDA to DCF both quantitatively using plate reader and qualitatively by confocal laser scanning microscopy. The inflammatory mediators macrophage inflammatory protein-2 (MIP-2), tumour necrosis factor-{alpha} (TNF-{alpha}) and interleukin-6, (IL-6) were measured by the enzyme linked immunosorbant assay (ELISA) following exposure of mouse macrophage cells to PAMAM dendrimers. A generation dependent ROS and cytokine production was found, which correlated well with the cytotoxicological response and therefore number of surface amino groups. A clear time sequence of increased ROS generation (maximum at {approx} 4 h), TNF-{alpha} and IL-6 secretion (maximum at {approx} 24 h), MIP-2 levels and cell death ({approx} 72 h) was observed. The intracellular ROS generation and cytokine production induced cytotoxicity point towards the mechanistic pathway of cell death upon exposure to PAMAM dendrimers.

  3. Effects of selected dietary secondary metabolites on reactive oxygen species production caused by iron(II) autoxidation.

    PubMed

    Chobot, Vladimir; Hadacek, Franz; Kubicova, Lenka

    2014-01-01

    Iron is an essential co-factor for many enzymes that catalyze electron transfer reactions. It is well known that so-called "poorly liganded" iron can increase ROS concentrations and trigger oxidative stress that is capable of initiating apoptosis. Conversely, controlled ROS production has been recognized as an integral part of cellular signaling. Elevated ROS concentrations are associated with aging, inflammatory and degenerative diseases. Anti-aging properties have been attributed especially to antioxidant phenolic plant metabolites that represent food additives in our diet. Consequently, this study explores the effects of flavonoids (quercetin and rutin), several phenolic acids (caffeic, chlorogenic, and protocatechuic acid), and the alkaloid caffeine on iron(II) autoxidation and ROS production in comparison to the standard antioxidants ascorbic acid and Trolox. The iron(II) autoxidation assay was carried out in pH 6.0 (plant apoplast and inflamed human tissue) and 7.4 (cell cytoplasm and human blood plasma). The obtained results accentuate phenolic acids as the more specific antioxidants compared to ascorbic acid and Trolox. Flavonoid redox chemistry depends more on the chemical milieu, specifically on pH. In vivo, the presence of iron cannot be ruled out and "wrongly" or "poorly" complexed iron has been pointed out as causative agent of various age-related diseases. PMID:25470272

  4. Effects of Selected Dietary Secondary Metabolites on Reactive Oxygen Species Production Caused by Iron(II) Autoxidation

    PubMed Central

    Chobot, Vladimir; Hadacek, Franz; Kubicova, Lenka

    2015-01-01

    Iron is an essential co-factor for many enzymes that catalyze electron transfer reactions. It is well known that so-called poorly liganded iron can increase ROS concentrations and trigger oxidative stress that is capable of initiating apoptosis. Conversely, controlled ROS production has been recognized as an integral part of cellular signaling. Elevated ROS concentrations are associated with aging, inflammatory and degenerative diseases. Anti-aging properties have been attributed especially to antioxidant phenolic plant metabolites that represent food additives in our diet. Consequently, this study explores the effects of flavonoids (quercetin and rutin), several phenolic acids (caffeic, chlorogenic, and protocatechuic acid), and the alkaloid caffeine on iron(II) autoxidation and ROS production in comparison to the standard antioxidants ascorbic acid and Trolox. The iron(II) autoxidation assay was carried out in pH 6.0 (plant apoplast and inflamed human tissue) and 7.4 (cell cytoplasm and human blood plasma). The obtained results accentuate phenolic acids as the more specific antioxidants compared to ascorbic acid and Trolox. Flavonoid redox chemistry depends more on the chemical milieu, specifically on pH. In vivo, the presence of iron cannot be ruled out and wrongly or poorly complexed iron has been pointed out as causative agent of various age-related diseases. PMID:25470272

  5. Reactive collisions of sulfur dioxide with molten carbonates

    PubMed Central

    Krebs, Thomas; Nathanson, Gilbert M.

    2010-01-01

    Molecular beam scattering experiments are used to investigate reactions of SO2 at the surface of a molten alkali carbonate eutectic at 683K. 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 10-6s, implying that the reaction takes place in a shallow liquid region less than 100? deep. The reaction probability does not vary between 683 and 883K, 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

  6. 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)

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

    2014-04-01

    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.

  7. Biofilm-Grown Burkholderia cepacia Complex Cells Survive Antibiotic Treatment by Avoiding Production of Reactive Oxygen Species

    PubMed Central

    Van Acker, Heleen; Sass, Andrea; Bazzini, Silvia; De Roy, Karen; Udine, Claudia; Messiaen, Thomas; Riccardi, Giovanna; Boon, Nico; Nelis, Hans J.; Mahenthiralingam, Eshwar; Coenye, Tom

    2013-01-01

    The presence of persister cells has been proposed as a factor in biofilm resilience. In the present study we investigated whether persister cells are present in Burkholderia cepacia complex (Bcc) biofilms, what the molecular basis of antimicrobial tolerance in Bcc persisters is, and how persisters can be eradicated from Bcc biofilms. After treatment of Bcc biofilms with high concentrations of various antibiotics often a small subpopulation survived. To investigate the molecular mechanism of tolerance in this subpopulation, Burkholderia cenocepacia biofilms were treated with 1024 µg/ml of tobramycin. Using ROS-specific staining and flow cytometry, we showed that tobramycin increased ROS production in treated sessile cells. However, approximately 0.1% of all sessile cells survived the treatment. A transcriptome analysis showed that several genes from the tricarboxylic acid cycle and genes involved in the electron transport chain were downregulated. In contrast, genes from the glyoxylate shunt were upregulated. These data indicate that protection against ROS is important for the survival of persisters. To confirm this, we determined the number of persisters in biofilms formed by catalase mutants. The persister fraction in ΔkatA and ΔkatB biofilms was significantly reduced, confirming the role of ROS detoxification in persister survival. Pretreatment of B. cenocepacia biofilms with itaconate, an inhibitor of isocitrate lyase (ICL), the first enzyme in the glyoxylate shunt, reduced the persister fraction approx. 10-fold when the biofilms were subsequently treated with tobramycin. In conclusion, most Bcc biofilms contain a significant fraction of persisters that survive treatment with high doses of tobramycin. The surviving persister cells downregulate the TCA cycle to avoid production of ROS and at the same time activate an alternative pathway, the glyoxylate shunt. This pathway may present a novel target for combination therapy. PMID:23516582

  8. ESEEM of industrial silica-bearing powders: reactivity of defects during wet processing in the ceramics production

    NASA Astrophysics Data System (ADS)

    Romanelli, Maurizio; Di Benedetto, Francesco; Fornaciai, Gabriele; Innocenti, Massimo; Montegrossi, Giordano; Pardi, Luca A.; Zoleo, Alfonso; Capacci, Fabio

    2015-05-01

    A study is undertaken to ascertain whether changes in the speciation of inorganic radicals are occurring during the ceramic industrial production that involves abundant silica powders as raw material. Industrial dusts were sampled in two ceramic firms, immediately after the wet mixing stage, performed with the aid of a relevant pressure. The dusts were then characterised by means of X-ray diffraction, analysis of the trace elements through chemical methods, granulometry, continuous-wave electron paramagnetic resonance (EPR) and pulsed electron spin echo envelope modulation (ESEEM) spectroscopies. The results of the characterisation point to a relevant change in the speciation of the two samples; namely, a prevailing contribution due to an inorganic radical different from that pertaining to pure quartz is pointed out. The combined interpretation of EPR and ESEEM data suggests the attribution of the main paramagnetic contribution to the A-centre in kaolinite, a constituent that is added to pure quartz at the initial stage of the ceramic production. In one of the two samples, a second weak EPR signal is attributed to the quartz's hAl species. By taking into account the relative quantities of quartz and kaolinite mixed in the two samples, and the relative abundances of the two radical species, we propose that the partial or complete suppression of the hAl species in favour of the A-centre of kaolinite has occurred. Although this change is apparently fostered by the mixture between quartz and another radical-bearing raw material, kaolinite, the suppression of the hAl centre of quartz is ascribed to the role played by the pressure and the wet environment during the industrial mixing procedure. This suppression provides a net change of radical speciation associated with quartz, when this phase is in contact with workers' respiratory system.

  9. β-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

    Bonfim-Mendonça, Patricia de Souza; Ratti, Bianca Altrão; 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

    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 β-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 α (TNF-α), interleukin-8 (IL-8), IL-1β, and IL-1Ra in neutrophils previously treated or not with β-glucan. In all of the assays, human neutrophils were challenged with C. albicans and C. glabrata isolated from vulvovaginal candidiasis. β-glucan significantly increased oxidant species production, suggesting that β-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 β-glucan appeared to be mainly related to the activation of reactive oxygen species and modulation of cytokine release. PMID:25229476

  10. Insights on the antitumor effects of kahweol on human breast cancer: Decreased survival and increased production of reactive oxygen species and cytotoxicity

    SciTech Connect

    Cárdenas, Casimiro; Quesada, Ana R.; Medina, Miguel Ángel

    2014-05-09

    Highlights: • Kahweol inhibits growth and attachment-independent proliferation of tumor cells. • Kahweol induces apoptosis in MDA-MB231 human breast cancer cells. • Kahweol-induced apoptosis involves caspase activation and cytochrome c release. • Kahweol does not protect against hydrogen peroxide cytotoxicity. • Kahweol increases hydrogen peroxide production by human breast cancer cells. - Abstract: The present study aims to identify the modulatory effects of kahweol, an antioxidant diterpene present in coffee beans, on a panel of human tumor cell lines. Kahweol inhibits tumor cell proliferation and clonogenicity and induces apoptosis in several kinds of human tumor cells. In the estrogen receptor-negative MDA-MB231 human breast cancer, the mentioned effects are accompanied by caspases 3/7 and 9 activation and cytochrome c release. On the other hand, kahweol increases the production of reactive oxygen species and their cytotoxicity in human breast cancer cells but not in normal cells. Taken together, our data suggest that kahweol is an antitumor compound with inhibitory effects on tumor cell growth and survival, especially against MDA-MB231 breast cancer cells.

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

    SciTech Connect

    Kobashigawa, Shinko; Suzuki, Keiji; Yamashita, Shunichi

    2011-11-04

    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.

  12. ?-Glucan induces reactive oxygen species production in human neutrophils to improve the killing of Candida albicans and Candida glabrata isolates from vulvovaginal candidiasis.

    PubMed

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

    2014-01-01

    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

  13. Functional Analysis of the Trichoderma harzianum nox1 Gene, Encoding an NADPH Oxidase, Relates Production of Reactive Oxygen Species to Specific Biocontrol Activity against Pythium ultimum?

    PubMed Central

    Montero-Barrientos, M.; Hermosa, R.; Cardoza, R. E.; Gutirrez, S.; Monte, E.

    2011-01-01

    The synthesis of reactive oxygen species (ROS) is one of the first events following pathogenic interactions in eukaryotic cells, and NADPH oxidases are involved in the formation of such ROS. The nox1 gene of Trichoderma harzianum was cloned, and its role in antagonism against phytopathogens was analyzed in nox1-overexpressed transformants. The increased levels of nox1 expression in these transformants were accompanied by an increase in ROS production during their direct confrontation with Pythium ultimum. The transformants displayed an increased hydrolytic pattern, as determined by comparing protease, cellulase, and chitinase activities with those for the wild type. In confrontation assays against P. ultimum the nox1-overexpressed transformants were more effective than the wild type, but not in assays against Botrytis cinerea or Rhizoctonia solani. A transcriptomic analysis using a Trichoderma high-density oligonucleotide (HDO) microarray also showed that, compared to gene expression for the interaction of wild-type T. harzianum and P. ultimum, genes related to protease, cellulase, and chitinase activities were differentially upregulated in the interaction of a nox1-overexpressed transformant with this pathogen. Our results show that nox1 is involved in T. harzianum ROS production and antagonism against P. ultimum. PMID:21421791

  14. Structure- and concentration-specific assessment of the physiological reactivity of ?-dicarbonyl glucose degradation products in peritoneal dialysis fluids.

    PubMed

    Distler, Leonie; Georgieva, Angelina; Kenkel, Isabell; Huppert, Jochen; Pischetsrieder, Monika

    2014-08-18

    In peritoneal dialysis (PD), glucose degradation products (GDPs), which are formed during heat sterilization of dialysis fluids, lead to structural and functional changes in the peritoneal membrane, which eventually result in the loss of its ultrafiltration capacity. To determine the molecular mechanisms behind these processes, the present study tested the influence of the six major ?-dicarbonyl GDPs in PD fluids, namely, glyoxal, methylglyoxal, 3-deoxyglucosone (3-DG), 3-deoxygalactosone (3-DGal), 3,4-dideoxyglucosone-3-ene (3,4-DGE), and glucosone with respect to their potential to impair the enzymatic activity of RNase A as well as their effects on cell viability. For comprehensive risk assessment, the ?-dicarbonyl GDPs were applied separately and in concentrations as present in conventional PD fluids. Thus, it was shown that after 5 days, glucosone impaired RNase A activity most distinctly (58% remaining activity, p < 0.001 compared to that of the control), followed by 3,4-DGE (62%, p < 0.001), 3-DGal (66%, p < 0.001), and 3-DG (76%, p < 0.01). Methylglyoxal and glyoxal caused weaker inactivation with significant effects only after 10 days of incubation (79%, 81%, p < 0.001). Profiling of the advanced glycation end products formed during the incubation of RNase A with methylglyoxal revealed predominant formation of the arginine modifications imidazolinone, CEA/dihydroxyimidazoline, and tetrahydropyrimidine at Arg10, Arg33, Arg39, and Arg85. Particularly, modification at Arg39 may severely affect the active site of the enzyme. Additionally, structure- and concentration-specific assessment of the cytotoxicity of the ?-dicarbonyl GDPs was performed. Although present at very low concentration, the cytotoxic effect of PD fluids after 2 days of incubation was exclusively caused by 3,4-DGE (14% cell viability, p < 0.001). After 4 days of incubation, 3-DGal (13% cell viability, p < 0.001), 3-DG (24%, p < 0.001), and, to a lower extent, glyoxal and methylglyoxal (both 57%, p < 0.01) also reduced cell viability significantly. In conclusion, 3,4-DGE, 3-DGal, and glucosone appear to be the most relevant parameters for the biocompatibility of PD fluids. PMID:25033248

  15. Acupuncture elicits neuroprotective effect by inhibiting NAPDH oxidase-mediated reactive oxygen species production in cerebral ischaemia

    PubMed Central

    Shi, Guang-Xia; Wang, Xue-Rui; Yan, Chao-Qun; He, Tian; Yang, Jing-Wen; Zeng, Xiang-Hong; Xu, Qian; Zhu, Wen; Du, Si-Qi; Liu, Cun-Zhi

    2015-01-01

    In the current study, we aimed to investigate whether NADPH oxidase, a major ROS-producing enzyme, was involved in the antioxidant effect of acupuncture on cognitive impairment after cerebral ischaemia. The cognitive function, infract size, neuron cell loss, level of superoxide anion and expression of NADPH oxidase subunit in hippocampus of two-vessel occlusion (2VO) rats were determined after 2-week acupuncture. Furthermore, the cognitive function and production of O2− were determined in the presence and absence of NADPH oxidase agonist (TBCA) and antagonist (Apocynin). The effect of acupuncture on cognitive function after cerebral ischaemia in gp91phox-KO mice was evaluated by Morris water maze. Acupuncture reduced infarct size, attenuated overproduction of O2−, and reversed consequential cognitive impairment and neuron cell loss in 2VO rats. The elevations of gp91phox and p47phox after 2VO were significantly decreased after acupuncture treatment. However, no differences of gp91phox mRNA were found among any experimental groups. Furthermore, these beneficial effects were reversed by TBCA, whereas apocynin mimicked the effect of acupuncture by improving cognitive function and decreasing O2− generation. Acupuncture failed to improve the memory impairment in gp91phox KO mice. Full function of the NADPH oxidase enzyme plays an important role in neuroprotective effects against cognitive impairment via inhibition of NAPDH oxidase-mediated oxidative stress. PMID:26656460

  16. Acupuncture elicits neuroprotective effect by inhibiting NAPDH oxidase-mediated reactive oxygen species production in cerebral ischaemia.

    PubMed

    Shi, Guang-Xia; Wang, Xue-Rui; Yan, Chao-Qun; He, Tian; Yang, Jing-Wen; Zeng, Xiang-Hong; Xu, Qian; Zhu, Wen; Du, Si-Qi; Liu, Cun-Zhi

    2015-01-01

    In the current study, we aimed to investigate whether NADPH oxidase, a major ROS-producing enzyme, was involved in the antioxidant effect of acupuncture on cognitive impairment after cerebral ischaemia. The cognitive function, infract size, neuron cell loss, level of superoxide anion and expression of NADPH oxidase subunit in hippocampus of two-vessel occlusion (2VO) rats were determined after 2-week acupuncture. Furthermore, the cognitive function and production of O2(-) were determined in the presence and absence of NADPH oxidase agonist (TBCA) and antagonist (Apocynin). The effect of acupuncture on cognitive function after cerebral ischaemia in gp91phox-KO mice was evaluated by Morris water maze. Acupuncture reduced infarct size, attenuated overproduction of O2(-), and reversed consequential cognitive impairment and neuron cell loss in 2VO rats. The elevations of gp91phox and p47phox after 2VO were significantly decreased after acupuncture treatment. However, no differences of gp91phox mRNA were found among any experimental groups. Furthermore, these beneficial effects were reversed by TBCA, whereas apocynin mimicked the effect of acupuncture by improving cognitive function and decreasing O2(-) generation. Acupuncture failed to improve the memory impairment in gp91phox KO mice. Full function of the NADPH oxidase enzyme plays an important role in neuroprotective effects against cognitive impairment via inhibition of NAPDH oxidase-mediated oxidative stress. PMID:26656460

  17. Reactivity of Ir(III) carbonyl complexes with water: alternative by-product formation pathways in catalytic methanol carbonylation.

    PubMed

    Elliott, Paul I P; Haak, Susanne; Meijer, Anthony J H M; Sunley, Glenn J; Haynes, Anthony

    2013-12-21

    The reactions of water with a number of iridium(III) complexes relevant to the mechanism for catalytic methanol carbonylation are reported. The iridium acetyl, [Ir(CO)2I3(COMe)](-), reacts with water under mild conditions to release CO2 and CH4, rather than the expected acetic acid. Isotopic labeling and kinetic experiments are consistent with a mechanism involving nucleophilic attack by water on a terminal CO ligand of [Ir(CO)2I3(COMe)](-) to give an (undetected) hydroxycarbonyl species. Subsequent decarboxylation and elimination of methane gives [Ir(CO)2I2](-). Similar reactions with water are observed for [Ir(CO)2I3Me](-), [Ir(CO)2(NCMe)I2(COMe)] and [Ir(CO)3I2Me] with the neutral complexes exhibiting markedly higher rates. The results demonstrate that CO2 formation during methanol carbonylation is not restricted to the conventional water gas shift mechanism mediated by [Ir(CO)2I4](-) or [Ir(CO)3I3], but can arise directly from key organo-iridium(III) intermediates in the carbonylation cycle. An alternative pathway for methane formation not involving the intermediacy of H2 is also suggested. A mechanism is proposed for the conversion MeOH + CO ? CO2 + CH4, which may account for the similar rates of formation of the two gaseous by-products during iridium-catalysed methanol carbonylation. PMID:24071892

  18. Heterogeneous OH oxidation of biomass burning organic aerosol surrogate compounds: assessment of volatilisation products and the role of OH concentration on the reactive uptake kinetics.

    PubMed

    Slade, Jonathan H; Knopf, Daniel A

    2013-04-28

    The reactive uptake coefficients (?) of OH by levoglucosan, abietic acid, and nitroguaiacol serving as surrogate compounds for biomass burning aerosol have been determined employing a chemical ionisation mass spectrometer coupled to a rotating-wall flow-tube reactor over a wide range of [OH] ?10(7)-10(11) molecule cm(-3). Volatilisation products of these organic substrates due to heterogeneous oxidation by OH have been determined at 1 atm using a high resolution proton transfer reaction time-of-flight mass spectrometer (HR-PTR-ToF-MS). ? range within 0.05-1 for [OH] = 2.6 10(7)-3 10(9) molecule cm(-3) for all investigated organic compounds, but decrease to 0.008-0.034 for [OH] = 4.1 10(10)-6.7 10(10) molecule cm(-3). ? as a function of [OH] can be described by a Langmuir-Hinshelwood model, neglecting bulk processes, suggesting that despite its strong reactivity, OH is mobile on surfaces prior to reaction. The best fit Langmuir-Hinshelwood parameters on average are K(OH) = 3.81 10(-10) cm(3) molecule(-1) and k(s) = 9.71 10(-17) cm(2) molecule(-1) s(-1) for all of the investigated organic compounds. Volatilised products have been identified indicating enhancements over background of 50% up to a factor of 15. Amongst the common volatile organic compounds (VOCs) identified between levoglucosan, abietic acid, and nitroguaiacol were methanol, acetaldehyde, formic acid, and acetic acid. VOCs having the greatest enhancement over background were glucic acid from levoglucosan, glycolic acid from abietic acid, and methanol and nitric acid from nitroguaiacol. Reaction mechanisms leading to the formation of glucic acid, glycolic acid, methanol, and nitric acid are proposed. Estimated lower limits of atmospheric lifetimes of biomass burning aerosol particles, 200 nm in diameter, by heterogeneous OH oxidation under fresh biomass burning plume conditions are ?2 days and up to ?2 weeks for atmospheric background conditions. However, estimated lifetimes depend crucially on [OH] and corresponding ?, emphasising the need to determine ? under relevant conditions. PMID:23487256

  19. Paclitaxel therapy potentiates cold hyperalgesia in streptozotocin-induced diabetic rats through enhanced mitochondrial reactive oxygen species production and TRPA1 sensitization.

    PubMed

    Barrire, David Andr; Rieusset, Jennifer; Chanteranne, Didier; Busserolles, Jrme; Chauvin, Marie-Agns; Chapuis, Latitia; Salles, Jrme; Dubray, Claude; Morio, Batrice

    2012-03-01

    Diabetes comorbidities include disabling peripheral neuropathy (DPN) and an increased risk of developing cancer. Antimitotic drugs, such as paclitaxel, are well known to facilitate the occurrence of peripheral neuropathy. Practitioners frequently observe the development or co-occurrence of enhanced DPN, especially cold sensitivity, in diabetic patients during chemotherapy. Preclinical studies showed that reactive oxygen species (ROS) and cold activate transient receptor potential ankyrin-1 (TRPA1) cation channels, which are involved in cold-evoked pain transduction signaling in DPN. Additionally, paclitaxel treatment has been associated with an accumulation of atypical mitochondria in the sensory nerves of rats. We hypothesized that paclitaxel might potentiate cold hyperalgesia by increasing mitochondrial injuries and TRPA1 activation. Thus, the kinetics of paclitaxel-induced cold hyperalgesia, mitochondrial ROS production, and TRPA1 expression were evaluated in dorsal root ganglia of normoglycemic and streptozotocin-induced diabetic rats. In diabetic rats, paclitaxel significantly enhanced cold hyperalgesia in comparison to normoglycemic paclitaxel-treated control rats. These effects were prevented by N-acetyl-cysteine, a reducing agent, and by HC030031, an antagonist of TRPA1. In diabetic and control rats, paclitaxel treatment was associated with an accumulation of atypical mitochondria and a 2-fold increase in mitochondrial ROS production. Moreover, mRNA levels of glutathione peroxidase 4 and glutathione-S-reductase were significantly lower in diabetic groups treated with paclitaxel. Finally, TRPA1 gene expression was enhanced by 45% in diabetic rats. Paclitaxel potentiation of cold hyperalgesia in diabetes may result from the combination of increased mitochondrial ROS production and poor radical detoxification induced by paclitaxel treatment and diabetes-related overexpression of TRPA1. PMID:22177224

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

    PubMed

    Chang, Mei-Chi; Chan, Chiu-Po; Wang, Ying-Jan; Lee, Po-Hsuen; Chen, Lin-I; Tsai, Yi-Ling; Lin, Bor-Ru; Wang, Yin-Lin; Jeng, Jiiang-Huei

    2007-01-15

    Sanguinarine is a benzopheanthridine alkaloid present in the root of Sanguinaria canadensis L. and Chellidonium majus L. In this study, sanguinarine (2 and 3 microM) 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 microM. Short-term exposure to sanguinarine (>0.5 microM) effectively suppressed the adhesion of KB cells to collagen and fibronectin (FN). Sanguinarine (2 and 3 microM) 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 microM) 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. PMID:17196629

  1. Central role of endogenous Toll-like receptor-2 activation in regulating inflammation, reactive oxygen species production, and subsequent neointimal formation after vascular injury

    SciTech Connect

    Shishido, Tetsuro . E-mail: Tetsuro_Shishido@URMC.Rochester.edu; Nozaki, Naoki; Takahashi, Hiroki; Arimoto, Takanori; Niizeki, Takeshi; Koyama, Yo; Abe, Jun-ichi; Takeishi, Yasuchika; Kubota, Isao

    2006-07-14

    Background: It is now evident that inflammation after vascular injury has significant impact on the restenosis after revascularization procedures such as angioplasty, stenting, and bypass grafting. However, the mechanisms that regulate inflammation and repair after vascular injury are incompletely understood. Here, we report that vascular injury-mediated cytokine expression, reactive oxygen species (ROS) production, as well as subsequent neointimal formation requires Toll-like receptor-2 (TLR-2) mediated signaling pathway in vivo. Methods and results: Vascular injury was induced by cuff-placement around the femoral artery in non-transgenic littermates (NLC) and TLR-2 knockout (TLR-2KO) mice. After cuff-placement in NLC mice, expression of TLR-2 was significantly increased in both smooth muscle medial layer and adventitia. Interestingly, we found that inflammatory genes expression such as tumor necrosis factor-{alpha}, interleukin-1{beta} (IL-1{beta}), IL-6, and monocyte chemoattractant protein-1 were markedly decreased in TLR-2KO mice compared with NLC mice. In addition, ROS production after vascular injury was attenuated in TLR-2KO mice compared with NLC mice. Since we observed the significant role of endogenous TLR-2 activation in regulating inflammatory responses and ROS production after vascular injury, we determined whether inhibition of endogenous TLR-2 activation can inhibit neointimal proliferation after vascular injury. Neointimal hyperplasia was markedly suppressed in TLR-2KO mice compared with WT mice at both 2 and 4 weeks after vascular injury. Conclusions: These findings suggested that endogenous TLR-2 activation might play a central role in the regulation of vascular inflammation as well as subsequent neointimal formation in injured vessels.

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

    SciTech Connect

    Chang, M.-C.; Chan, C.-P.; Wang, Y.-J.; Lee, P.-H.; Chen, L.-I; Tsai, Y.-L.; Lin, B.-R.; Wang, Y.-L.; Jeng, J.-H. . E-mail: huei@ha.mc.ntu.edu.tw

    2007-01-15

    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.

  3. DEXH Box RNA HelicaseMediated Mitochondrial Reactive Oxygen Species Production in Arabidopsis Mediates Crosstalk between Abscisic Acid and Auxin Signaling[C][W][OA

    PubMed Central

    He, Junna; Duan, Ying; Hua, Deping; Fan, Guangjiang; Wang, Li; Liu, Yue; Chen, Zhizhong; Han, Lihua; Qu, Li-Jia; Gong, Zhizhong

    2012-01-01

    It is well known that abscisic acid (ABA) promotes reactive oxygen species (ROS) production through plasma membraneassociated NADPH oxidases during ABA signaling. However, whether ROS from organelles can act as second messengers in ABA signaling is largely unknown. Here, we identified an ABA overly sensitive mutant, abo6, in a genetic screen for ABA-mediated inhibition of primary root growth. ABO6 encodes a DEXH box RNA helicase that is involved in regulating the splicing of several genes of complex I in mitochondria. The abo6 mutant accumulated more ROS in mitochondria, as established using a mitochondrial superoxide indicator, circularly permuted yellow fluorescent protein. Two dominant-negative mutations in ABA insensitive1 (abi1-1) and abi2-1 greatly reduced ROS production in mitochondria. The ABA sensitivity of abo6 can also be compromised by the atrbohF mutation. ABA-mediated inhibition of seed germination and primary root growth in abo6 was released by the addition of reduced GSH and exogenous auxin to the medium. Expression of auxin-responsive markers ProDR5:GUS (for synthetic auxin response element D1-4 with site-directed mutants in the 5?-end from soybean):?-glucuronidase) and Indole-3-acetic acid inducible2:GUS was greatly reduced by the abo6 mutation. Hence, our results provide molecular evidence for the interplay between ABA and auxin through the production of ROS from mitochondria. This interplay regulates primary root growth and seed germination in Arabidopsis thaliana. PMID:22652060

  4. Reactive scattering calculations for {sup 87}Rb+{sup 87}RbHe→Rb{sub 2}({sup 3}Σ{sub u}{sup +},v)+He from ultralow to intermediate energies

    SciTech Connect

    Rodríguez-Cantano, Rocío; González-Lezana, Tomás; Prosmiti, Rita; Delgado-Barrio, Gerardo; Villarreal, Pablo; Jellinek, Julius

    2015-04-28

    We investigate atom-diatom reactive collisions, as a preliminary step, in order to assess the possibility of forming Rb{sub 2} molecules in their lowest triplet electronic state by cold collisions of rubidium atoms on the surface of helium nanodroplets. A simple model related to the well-known Rosen treatment of linear triatomic molecules [N. Rosen, J. Chem. Phys. 1, 319 (1933)] in relative coordinates is used, allowing to estimate reactive probabilities for different values of the total angular momentum. The best available full dimensional potential energy surface [Guillon et al., J. Chem. Phys. 136, 174307 (2012)] is employed through the calculations. Noticeable values of the probabilities in the ultracold regime, which numerically fulfill the Wigner threshold law, support the feasibility of the process. The rubidium dimer is mainly produced at high vibrational states, and the reactivity is more efficient for a bosonic helium partner than when the fermion species is considered.

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

    NASA Technical Reports Server (NTRS)

    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

    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.

  6. Reactive oxygen species generated by a heat shock protein (Hsp) inducing product contributes to Hsp70 production and Hsp70-mediated protective immunity in Artemia franciscana against pathogenic vibrios.

    PubMed

    Baruah, Kartik; Norouzitallab, Parisa; Linayati, Linayati; Sorgeloos, Patrick; Bossier, Peter

    2014-10-01

    The cytoprotective role of heat shock protein (Hsp70) described in a variety of animal disease models, including vibriosis in farmed aquatic animals, suggests that new protective strategies relying upon the use of compounds that selectively turn on Hsp genes could be developed. The product Tex-OE (hereafter referred to as Hspi), an extract from the skin of the prickly pear fruit, Opuntia ficus indica, was previously shown to trigger Hsp70 synthesis in a non-stressful situation in a variety of animals, including in a gnotobiotically (germ-free) cultured brine shrimp Artemia franciscana model system. This model system offers great potential for carrying out high-throughput, live-animal screens of compounds that have health benefit effects. By using this model system, we aimed to disclose the underlying cause behind the induction of Hsp70 by Hspi in the shrimp host, and to determine whether the product affects the shrimp in inducing resistance towards pathogenic vibrios. We provide unequivocal evidences indicating that during the pretreatment period with Hspi, there is an initial release of reactive oxygen species (hydrogen peroxide and/or superoxide anion), generated by the added product, in the rearing water and associated with the host. The reactive molecules generated are the triggering factors responsible for causing Hsp70 induction within Artemia. We have also shown that Hspi acts prophylactically at an optimum dose regimen to confer protection against pathogenic vibrios. This salutary effect was associated with upregulation of two important immune genes, prophenoloxidase and transglutaminase of the innate immune system. These findings suggest that inducers of stress protein (e.g. Hsp70) are potentially important modulator of immune responses and might be exploited to confer protection to cultured shrimp against Vibrio infection. PMID:24950414

  7. Production of two charm quark-antiquark pairs in single-parton scattering within the kt-factorization approach

    NASA Astrophysics Data System (ADS)

    van Hameren, Andreas; Maciu?a, Rafa?; Szczurek, Antoni

    2015-09-01

    We present first results for the 2 ? 4 single-parton scattering gg ? c c bar c c bar subprocess for the first time fully within the kt-factorization approach. In this calculation we have used the Kimber-Martin-Ryskin unintegrated gluon distribution which effectively includes some class of higher-order gluon emissions, and an off-shell matrix element squared calculated using recently developed techniques. The results are compared with our earlier result obtained within the collinear-factorization approach. Only slightly larger cross sections are obtained than in the case of the collinear approach. Inclusion of transverse momenta of gluons entering the hard process leads to a much stronger azimuthal decorrelation between cc and c bar c bar than in the collinear-factorization approach. A comparison to predictions of double parton scattering (DPS) results and the LHCb data strongly suggests that the assumption of two fully independent DPS (gg ? c c bar ? gg ? c c bar) may be too approximate.

  8. Gamma scattering

    SciTech Connect

    Baker, A.G.

    1980-01-01

    Experimental examinations have been performed on a gamma scattering source/detector configuration that is believed to have the potential for providing density information at a finite number of positions along the primary beam and the average attenuation along the exit rays from those positions. Scattering spectra were acquired for several void-fluid density distribution simulations. The multiple-scattered photon contribution to the total acquired spectrum from a water-filled pipe simulation was extracted and found to be between 18 to 33% of the total counts in the single-scattered photon energy region, with a region average of 24%.

  9. Measurement of the 477.6-keV γ -ray production cross section following inelastic neutron scattering by 7Li

    NASA Astrophysics Data System (ADS)

    Nyman, M.; Belloni, F.; Ichinkhorloo, D.; Pirovano, E.; Plompen, A. J. M.; Rouki, C.

    2016-02-01

    The γ -ray production cross section for the 477.6-keV 1 /2-→3 /2g.s . - transition in 7Li following inelastic neutron scattering has been measured from the reaction threshold up to 18 MeV. This cross section is interesting as a possible standard for other γ -ray production cross-section measurements. The experiment was conducted at the GELINA pulsed white neutron source with the GAINS spectrometer consisting of 12 high-purity germanium detectors. The time-of-flight method was used for neutron energy determination. The sample was an optical-quality lithium fluoride disk and the neutron flux was monitored using a 235U fission chamber. Previous measurements of this cross section are reviewed and compared with our results. Recently, the examined cross section has been calculated using the continuum-discretized coupled-channels method. The results are found to be in reasonable agreement with the experimental data.

  10. 5-Aminolevulinic acid strongly enhances delayed intracellular production of reactive oxygen species (ROS) generated by ionizing irradiation: quantitative analyses and visualization of intracellular ROS production in glioma cells in vitro.

    PubMed

    Kitagawa, Takehiro; Yamamoto, Junkoh; Tanaka, Tohru; Nakano, Yoshiteru; Akiba, Daisuke; Ueta, Kunihiro; Nishizawa, Shigeru

    2015-02-01

    Postoperative adjuvant radiotherapy has important roles in multimodal treatment for highly aggressive malignant gliomas. Previously, we demonstrated that multi-dose ionizing irradiation with repetitive administration of 5-aminolevulinic acid (5-ALA) enhanced the host antitumor response and strongly inhibited tumor growth in experimental glioma. However, the mechanism of the radiosensitizing effect of 5-ALA is not known. Ionizing irradiation not only causes reactive oxygen species (ROS) formation initially by water radiolysis but also induces delayed production of mitochondrial ROS for mediating the long-lasting effects of ionizing irradiation on tumor cells. 5-ALA leads to high accumulation of protoporphyrin IX (PpIX) in the mitochondria of tumor cells, yet can also improve dysfunction of the mitochondrial respiratory chain in tumor cells. Here, we assessed the effect of 5-ALA-induced PpIX synthesis and delayed production of intracellular ROS after ionizing irradiation with 5-ALA in glioma cells in vitro. Temporal changes in intracellular 5-ALA-induced PpIX synthesis after ionizing irradiation in glioma cell lines were evaluated using flow cytometry (FCM). Then, the effect of 5-ALA on delayed production of intracellular ROS 12 h after ionizing irradiation in glioma cells was evaluated by FCM and confocal laser scanning microscopy. Ionizing irradiation had no effect on 5-ALA-induced PpIX synthesis in glioma cells. Delayed intracellular production of ROS was significantly higher than that just after ionizing irradiation, but 5-ALA pretreatment strongly enhanced the delayed intracellular production of ROS, mainly in the cytoplasm of glioma cells. This 5-ALA-induced increase in the delayed production of ROS tended to be higher in the case of 5-ALA treatment before rather than after ionizing irradiation. These results suggest that 5-ALA can affect tumor cells under ionizing irradiation, and greatly increase secondary intracellular production of ROS long after ionizing irradiation, thereby causing a radiosensitizing effect in glioma cells. PMID:25420428

  11. Reactivation of IgG-switched memory B cells by BCR-intrinsic signal amplification promotes IgG antibody production.

    PubMed

    Lutz, Johannes; Dittmann, Kai; Bsl, Michael R; Winkler, Thomas H; Wienands, Jrgen; Engels, Niklas

    2016-01-01

    Secondary antibody responses are marked by faster kinetics, improved antibody affinity and a switch from IgM to other immunoglobulin isotypes, most notably IgG, compared with primary responses. These changes protect from reinfection and represent the principle of most vaccination strategies. Yet, the molecular mechanisms that underlie B-cell memory responses are unclear. Here we show, by inactivating the immunoglobulin tail tyrosine (ITT) signalling motif of membrane-bound IgG1 in the mouse, that the ITT facilitates maintenance and reactivation of IgG-switched memory B cells in vivo. The ITT motif equips IgG-switched cells with enhanced BCR signalling capacity, which supports their competitiveness in secondary immune reactions and drives the formation of IgG-secreting plasma cells even in the absence of T-cell help. Our results demonstrate that ITT signalling promotes the vigorous production of IgG antibodies and thus provide a molecular basis for humoral immunological memory. PMID:26815242

  12. Reactivation of IgG-switched memory B cells by BCR-intrinsic signal amplification promotes IgG antibody production

    PubMed Central

    Lutz, Johannes; Dittmann, Kai; Bösl, Michael R; Winkler, Thomas H; Wienands, Jürgen; Engels, Niklas

    2015-01-01

    Secondary antibody responses are marked by faster kinetics, improved antibody affinity and a switch from IgM to other immunoglobulin isotypes, most notably IgG, compared with primary responses. These changes protect from reinfection and represent the principle of most vaccination strategies. Yet, the molecular mechanisms that underlie B-cell memory responses are unclear. Here we show, by inactivating the immunoglobulin tail tyrosine (ITT) signalling motif of membrane-bound IgG1 in the mouse, that the ITT facilitates maintenance and reactivation of IgG-switched memory B cells in vivo. The ITT motif equips IgG-switched cells with enhanced BCR signalling capacity, which supports their competitiveness in secondary immune reactions and drives the formation of IgG-secreting plasma cells even in the absence of T-cell help. Our results demonstrate that ITT signalling promotes the vigorous production of IgG antibodies and thus provide a molecular basis for humoral immunological memory. PMID:26815242

  13. [Hyperoxia induces reactive oxygen species production and promotes SIRT1 nucleocytoplasmic shuttling of peripheral blood mononuclear cells in premature infants in vitro].

    PubMed

    Yang, Xi; Dong, Wenbin; Li, Qingping; Kang, Lan; Lei, Xiaoping; Zhang, Lianyu; Lu, Youying; Zhai, Xuesong

    2015-12-01

    Objective To explore the relationship between deacetylase sirtuin 1 (SIRT1) and reactive oxygen species (ROS) after oxygen therapy in the peripheral blood mononuclear cells (PBMCs) of the premature infants. Methods According to the fraction of inspired O2 (FiO2), premature infants diagnosed with respiratory distress syndrome (RDS) (gestational age <32 weeks), were divided into three groups: low dosage oxygen group (FiO2 <300 mL/L), moderate dosage oxygen group (FiO2; 300 mL/L-400 mL/L), high dosage oxygen group (FiO2 >400 mL/L). After 48 hours of oxygen treatment, PBMCs and serum were collected from the peripheral blood. Then the intracellular ROS level was detected by MitoSOX(TM) Red labeling combined with confocal laser scanning microscopy; the malondialdehyde (MDA) content in the serum was determined by the whole spectrum spectrophotometer; the SIRT1 localization was observed by immunofluorescence staining; and the SIRT1 levels in PBMCs were examined by Western blotting. Results With the increase of FiO2, the ROS, MDA content and the rate of SIRT1 nucleocytoplasmic shuttling of PBMCs gradually increased and SIRT1 protein expression was significantly lowered. Conclusion Hyperoxia induces ROS production in premature infants, promotes SIRT1 to cross from nucleus to cytoplasm, inhibits the resistant ability of SIRT1 to oxidative stress. PMID:26648302

  14. Apoptosis-inducing active components from Corbicula fluminea through activation of caspase-2 and production of reactive oxygen species in human leukemia HL-60 cells.

    PubMed

    Huang, Ying-Tang; Huang, Yi-Hsuan; Hour, Tzhy-Chyuan; Pan, Bonnie Sun; Liu, Yeuk-Chuen; Pan, Min-Hsiung

    2006-08-01

    The anti-cancer effects and possible mechanisms of the freshwater clam (Corbicula fluminea Muller) and its active compounds (FME) on cell viability in human leukemia HL-60 cells were investigated. This study demonstrated that FME was able to inhibit cell proliferation in a concentration- and time-dependent manner. Treatment with FME caused induction of caspase-2, caspase-3, caspase-6, caspase-8, and caspase-9 activity in a time-dependent manner, but not affect caspase-1 activity; it induced the proteolysis of DNA fragmentation factor (DFF-45) and poly(ADP-ribose) polymerase (PARP). Induction of cell death by FME was completely prevented by a pan-caspase inhibitor, Z-Val-Ala-Asp-fluoromethyl ketone (Z-VAD-FMK) and a caspase-2 inhibitor, Z-Val-Asp-Val-Ala-Asp-FMK (Z-VDVAD-FMK). Furthermore, treatment with FME caused a rapid loss of mitochondrial transmembrane potential, stimulation of generation of reactive oxygen species (ROS), release of mitochondrial cytochrome c into cytosol, and GSH depletion. Anti-oxidants such as N-acetylcysteine, catalase, superoxide dismutase, allopurinol, and pyrrolidine dithiocarbamate, but not diphenylene iodonium, significantly inhibited FME-induced cell death. In addition, the results showed that FME-induced apoptosis was accompanied by up-regulation of Bax and Bad, and down-regulation of Bcl-2 and Bcl-XL. Taken together, induction of apoptosis on HL-60 cells by FME was mainly associated with ROS production, GSH depletion, mitochondrial dysfunction, and caspase activation. PMID:16545898

  15. Jaridonin, a novel ent-kaurene diterpenoid from Isodon rubescens, inducing apoptosis via production of reactive oxygen species in esophageal cancer cells.

    PubMed

    Ma, Yong-Cheng; Ke, Yu; Zi, Xiaolin; Zhao, Wen; Shi, Xiao-Jing; Liu, Hong-Min

    2013-07-01

    Isodon rubescens, a Chinese herb, has been used as a folk, botanical medicine in China for inflammatory diseases and cancer treatment for many years. Recently, we isolated a new ent-kaurene diterpenoid, named Jaridonin, from Isodon rubescens. The chemical structure of Jaridonin was verified by infrared (IR), nuclear magnetic resonance (NMR), and mass spectrum (MS) data as well as X-ray spectra. Jaridonin potently reduced viabilities of several esophageal cancer cell lines, including EC109, EC9706 and EC1. Jaridonin treatment resulted in typical apoptotic morphological characteristics, increased the number of annexin V-positive staining cells, as well as caused a G2/M arrest in cell cycle progression. Furthermore, Jaridonin resulted in a significant loss of mitochondrial membrane potential, release of cytochrome c into the cytosol, and then activation of Caspase-9 and -3, leading to activation of the mitochondria mediated apoptosis. Furthermore, these effects of Jaridonin were accompanied by marked reactive oxygen species (ROS) production and increased expression of p53, p21(waf1/Cip1) and Bax, whereas two ROS scavengers, N-acetyl-L-cysteine (LNAC) and Vitamin C, significantly attenuated the effects of Jaridonin on the mitochondrial membrane potential, DNA damage, expression of p53 and p21(waf1/Cip1) and reduction of cell viabilities. Taken together, our results suggest that a natural ent-kaurenoid diterpenoid, Jaridonin, is a novel apoptosis inducer and deserves further investigation as a new chemotherapeutic strategy for patients with esophageal cancer. PMID:23597192

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

    PubMed Central

    Behrendt, Lars; Staal, Marc; Cristescu, Simona M; Harren, Frans JM; Schliep, Martin; Larkum, Anthony WD; Kühl, Michael

    2013-01-01

    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

  17. Reducing Cytoplasmic Polyamine Oxidase Activity in Arabidopsis Increases Salt and Drought Tolerance by Reducing Reactive Oxygen Species Production and Increasing Defense Gene Expression.

    PubMed

    Sagor, G H M; Zhang, Siyuan; Kojima, Seiji; Simm, Stefan; Berberich, Thomas; Kusano, Tomonobu

    2016-01-01

    The link between polyamine oxidases (PAOs), which function in polyamine catabolism, and stress responses remains elusive. Here, we address this issue using Arabidopsis pao mutants in which the expression of the five PAO genes is knocked-out or knocked-down. As the five single pao mutants and wild type (WT) showed similar response to salt stress, we tried to generate the mutants that have either the cytoplasmic PAO pathway (pao1 pao5) or the peroxisomal PAO pathway (pao2 pao3 pao4) silenced. However, the latter triple mutant was not obtained. Thus, in this study, we used two double mutants, pao1 pao5 and pao2 pao4. Of interest, pao1 pao5 mutant was NaCl- and drought-tolerant, whereas pao2 pao4 showed similar sensitivity to those stresses as WT. To reveal the underlying mechanism of salt tolerance, further analyses were performed. Na uptake of the mutant (pao1 pao5) decreased to 75% of WT. PAO activity of the mutant was reduced to 62% of WT. The content of reactive oxygen species (ROS) such as hydrogen peroxide, a reaction product of PAO action, and superoxide anion in the mutant became 81 and 72% of the levels in WT upon salt treatment. The mutant contained 2.8-fold higher thermospermine compared to WT. Moreover, the mutant induced the genes of salt overly sensitive-, abscisic acid (ABA)-dependent- and ABA-independent- pathways more strongly than WT upon salt treatment. The results suggest that the Arabidopsis plant silencing cytoplasmic PAOs shows salinity tolerance by reducing ROS production and strongly inducing subsets of stress-responsive genes under stress conditions. PMID:26973665

  18. Reducing Cytoplasmic Polyamine Oxidase Activity in Arabidopsis Increases Salt and Drought Tolerance by Reducing Reactive Oxygen Species Production and Increasing Defense Gene Expression

    PubMed Central

    Sagor, G. H. M.; Zhang, Siyuan; Kojima, Seiji; Simm, Stefan; Berberich, Thomas; Kusano, Tomonobu

    2016-01-01

    The link between polyamine oxidases (PAOs), which function in polyamine catabolism, and stress responses remains elusive. Here, we address this issue using Arabidopsis pao mutants in which the expression of the five PAO genes is knocked-out or knocked-down. As the five single pao mutants and wild type (WT) showed similar response to salt stress, we tried to generate the mutants that have either the cytoplasmic PAO pathway (pao1 pao5) or the peroxisomal PAO pathway (pao2 pao3 pao4) silenced. However, the latter triple mutant was not obtained. Thus, in this study, we used two double mutants, pao1 pao5 and pao2 pao4. Of interest, pao1 pao5 mutant was NaCl- and drought-tolerant, whereas pao2 pao4 showed similar sensitivity to those stresses as WT. To reveal the underlying mechanism of salt tolerance, further analyses were performed. Na uptake of the mutant (pao1 pao5) decreased to 75% of WT. PAO activity of the mutant was reduced to 62% of WT. The content of reactive oxygen species (ROS) such as hydrogen peroxide, a reaction product of PAO action, and superoxide anion in the mutant became 81 and 72% of the levels in WT upon salt treatment. The mutant contained 2.8-fold higher thermospermine compared to WT. Moreover, the mutant induced the genes of salt overly sensitive-, abscisic acid (ABA)-dependent- and ABA-independent- pathways more strongly than WT upon salt treatment. The results suggest that the Arabidopsis plant silencing cytoplasmic PAOs shows salinity tolerance by reducing ROS production and strongly inducing subsets of stress-responsive genes under stress conditions. PMID:26973665

  19. 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

    Mesa-Arango, Ana Cecilia; Trevijano-Contador, Nuria; Romn, Elvira; Snchez-Fresneda, Ruth; Casas, Celia; Herrero, Enrique; Argelles, Juan Carlos; Pla, Jess; Cuenca-Estrella, Manuel; Zaragoza, Oscar

    2014-11-01

    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

  20. [Diphenylene iodonium and apocynin reduce the translocation and level of p47phox in PBMCs of premature infants to inhibit reactive oxygen species production].

    PubMed

    Zhang, Lingping; Dong, Wenbin; Li, Qingping; Kang, Lan; Zhang, Lianyu; Lu, Youying; Zhai, Xuesong

    2016-01-01

    Objective To observe the effects of NADPH oxidase inhibitor diphenylene iodonium (DPI) and apocynin on the generation of reactive oxygen species (ROS) induced by p47phox and the mechanism of p47phox-induced ROS production under hyperoxic conditions. Methods Peripheral blood mononuclear cells (PBMCs) were isolated from the peripheral blood (2 mL) of premature infants of less than 32 weeks without oxygen uptake. The isolated cells were divided into four groups, control group, hyperoxia group, hyperoxia and DPI group, hyperoxia and apocynin group. The control group was cultured in incubator with 50 mL/L CO2 at 37DegreesCelsius, and the other groups were cultured in 950 mL/L O2 and 50 mL/L CO2 mixed gas. After 48 hours, ROS was detected by Mitosox Red staining under a confocal laser scanning microscope; malondialdehyde (MDA) was measured by thiobarbituric acid colorimetry; the location and translocation rate of p47phox was observed by immunofluorescence staining; the level of p47phox protein was tested by Western blotting. Results Compared with the hyperoxia group, the remaining three groups showed significantly decreased ROS and MDA levels and reduced translocation rate and level of p47phox. Compared with the control group, both the hyperoxia and DPI group and the hyperoxia and apocynin group were not significantly different in the above indexes. Conclusion DPI and apocynin can reduce hyperoxia-induced ROS production by decreasing the translocation and level of p47phox. PMID:26728380

  1. The Plant Defense Elicitor Cryptogein Stimulates Clathrin-Mediated Endocytosis Correlated with Reactive Oxygen Species Production in Bright Yellow-2 Tobacco Cells1[C

    PubMed Central

    Leborgne-Castel, Nathalie; Lherminier, Jeannine; Der, Christophe; Fromentin, Jrme; Houot, Valrie; Simon-Plas, Franoise

    2008-01-01

    The plant defense elicitor cryptogein triggers well-known biochemical events of early signal transduction at the plasma membrane of tobacco (Nicotiana tabacum) cells, but microscopic observations of cell responses related to these early events were lacking. We determined that internalization of the lipophilic dye FM4-64, which is a marker of endocytosis, is stimulated a few minutes after addition of cryptogein to tobacco Bright Yellow-2 (BY-2) cells. This stimulation is specific to the signal transduction pathway elicited by cryptogein because a lipid transfer protein, which binds to the same receptor as cryptogein but without triggering signaling, does not increase endocytosis. To define the nature of the stimulated endocytosis, we quantified clathrin-coated pits (CCPs) forming on the plasma membrane of BY-2 cells. A transitory stimulation of this morphological event by cryptogein occurs within the first 15 min. In the presence of cryptogein, increases in both FM4-64 internalization and clathrin-mediated endocytosis are specifically blocked upon treatment with 5 ?m tyrphostin A23, a receptor-mediated endocytosis inhibitor. The kinetics of the transient increase in CCPs at the plasma membrane coincides with that of transitory reactive oxygen species (ROS) production occurring within the first 15 min after elicitation. Moreover, in BY-2 cells expressing NtrbohD antisense cDNA, which are unable to produce ROS when treated with cryptogein, the CCP stimulation is inhibited. These results indicate that the very early endocytic process induced by cryptogein in tobacco is due, at least partly, to clathrin-mediated endocytosis and is dependent on ROS production by the NADPH oxidase NtrbohD. PMID:18184734

  2. The plant defense elicitor cryptogein stimulates clathrin-mediated endocytosis correlated with reactive oxygen species production in bright yellow-2 tobacco cells.

    PubMed

    Leborgne-Castel, Nathalie; Lherminier, Jeannine; Der, Christophe; Fromentin, Jrme; Houot, Valrie; Simon-Plas, Franoise

    2008-03-01

    The plant defense elicitor cryptogein triggers well-known biochemical events of early signal transduction at the plasma membrane of tobacco (Nicotiana tabacum) cells, but microscopic observations of cell responses related to these early events were lacking. We determined that internalization of the lipophilic dye FM4-64, which is a marker of endocytosis, is stimulated a few minutes after addition of cryptogein to tobacco Bright Yellow-2 (BY-2) cells. This stimulation is specific to the signal transduction pathway elicited by cryptogein because a lipid transfer protein, which binds to the same receptor as cryptogein but without triggering signaling, does not increase endocytosis. To define the nature of the stimulated endocytosis, we quantified clathrin-coated pits (CCPs) forming on the plasma membrane of BY-2 cells. A transitory stimulation of this morphological event by cryptogein occurs within the first 15 min. In the presence of cryptogein, increases in both FM4-64 internalization and clathrin-mediated endocytosis are specifically blocked upon treatment with 5 microm tyrphostin A23, a receptor-mediated endocytosis inhibitor. The kinetics of the transient increase in CCPs at the plasma membrane coincides with that of transitory reactive oxygen species (ROS) production occurring within the first 15 min after elicitation. Moreover, in BY-2 cells expressing NtrbohD antisense cDNA, which are unable to produce ROS when treated with cryptogein, the CCP stimulation is inhibited. These results indicate that the very early endocytic process induced by cryptogein in tobacco is due, at least partly, to clathrin-mediated endocytosis and is dependent on ROS production by the NADPH oxidase NtrbohD. PMID:18184734

  3. 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

    2014-01-01

    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

  4. Insulin improves in vitro survival of equine preantral follicles enclosed in ovarian tissue and reduces reactive oxygen species production after culture.

    PubMed

    Aguiar, F L N; Lunardi, F O; Lima, L F; Rocha, R M P; Bruno, J B; Magalhães-Padilha, D M; Cibin, F W S; Rodrigues, A P R; Gastal, M O; Gastal, E L; Figueiredo, J R

    2016-04-01

    This study investigated the effect of insulin concentration on the in vitro culture of equine preantral follicles enclosed in ovarian tissue. Ovarian tissue samples were immediately fixed (noncultured control) or cultured for 1 or 7 days in α-MEM(+) supplemented with 0 ng/mL, 10 ng/mL, or 10 μg/mL insulin. Ovarian tissues were processed and analyzed by classical histology. Culture medium samples were collected after 1 and 7 days of culture for steroid and reactive oxygen species (ROS) analyses. The percentage of morphologically normal follicles was greater (P < 0.001) in insulin-treated groups after 1 day of culture; likewise, more (P < 0.02) normal follicles were observed after 7 days of culture in medium supplemented with 10-ng/mL insulin. Furthermore, an increase (P < 0.01) in developing (transition, primary, and secondary) follicles between Days 1 and 7 of culture was observed only with the 10-ng/mL insulin treatment. ROS production after 1 or 7 days of culture was lower (P < 0.0001) in medium with 10-ng/mL insulin than the other treatments. Ovarian tissues containing preantral follicles were able to produce estradiol and progesterone after 1 and 7 days of culture; however, treatments did not differ in steroid production. In conclusion, the use of a physiological concentration (10 ng/mL) of insulin rather than the previously reported concentration (10 μg/mL) for in vitro culture of equine preantral follicles improved follicular survival and growth and lowered oxidative stress. Results from this study shed light on new perspectives for producing an appropriate medium to improve equine preantral follicle in vitro survival and growth. PMID:26777561

  5. Isolation of Terpenoids from the Stem of Ficus aurantiaca Griff and their Effects on Reactive Oxygen Species Production and Chemotactic Activity of Neutrophils.

    PubMed

    Mawa, Shukranul; Jantan, Ibrahim; Husain, Khairana

    2016-01-01

    Three new triterpenoids; namely 28,28,30-trihydroxylupeol (1); 3,21,21,26-tetrahydroxy-lanostanoic acid (2) and dehydroxybetulinic acid (3) and seven known compounds; i.e., taraxerone (4); taraxerol (5); ethyl palmitate (6); herniarin (7); stigmasterol (8); ursolic acid (9) and acetyl ursolic acid (10) were isolated from the stem of Ficus aurantiaca Griff. The structures of the compounds were established by spectroscopic techniques. The compounds were evaluated for their inhibitory effects on polymorphonuclear leukocyte (PMN) chemotaxis by using the Boyden chamber technique and on human whole blood and neutrophil reactive oxygen species (ROS) production by using a luminol-based chemiluminescence assay. Among the compounds tested, compounds 1-4, 6 and 9 exhibited strong inhibition of PMN migration towards the chemoattractant N-formyl-methionyl-leucyl-phenylalanine (fMLP) with IC50 values of 6.8; 2.8; 2.5; 4.1; 3.7 and 3.6 μM, respectively, comparable to that of the positive control ibuprofen (6.7 μM). Compounds 2-4, 6, 7 and 9 exhibited strong inhibition of ROS production of PMNs with IC50 values of 0.9; 0.9; 1.3; 1.1; 0.5 and 0.8 μM, respectively, which were lower than that of aspirin (9.4 μM). The bioactive compounds might be potential lead molecules for the development of new immunomodulatory agents to modulate the innate immune response of phagocytes. PMID:26742027

  6. 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 Central

    Mesa-Arango, Ana Cecilia; Trevijano-Contador, Nuria; Romn, Elvira; Snchez-Fresneda, Ruth; Casas, Celia; Herrero, Enrique; Argelles, Juan Carlos; Pla, Jess; Cuenca-Estrella, Manuel

    2014-01-01

    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

  7. Vacuum solutions of five dimensional Einstein equations generated by inverse scattering method. II. Production of the black ring solution

    SciTech Connect

    Tomizawa, Shinya; Nozawa, Masato

    2006-06-15

    We study vacuum solutions of five-dimensional Einstein equations generated by the inverse scattering method. We reproduce the black ring solution which was found by Emparan and Reall by taking the Euclidean Levi-Civita metric plus one-dimensional flat space as a seed. This transformation consists of two successive processes; the first step is to perform the three-solitonic transformation of the Euclidean Levi-Civita metric with one-dimensional flat space as a seed. The resulting metric is the Euclidean C-metric with extra one-dimensional flat space. The second is to perform the two-solitonic transformation by taking it as a new seed. Our result may serve as a stepping stone to find new exact solutions in higher dimensions.

  8. Sensitivities in the production of spread-out Bragg peak dose distributions by passive scattering with beam current modulation.

    PubMed

    Lu, Hsiao-Ming; Brett, Robert; Engelsman, Martijn; Slopsema, Roelf; Kooy, Hanne; Flanz, Jay

    2007-10-01

    A spread-out Bragg peak (SOBP) is used in proton beam therapy to create a longitudinal conformality of the required dose to the target. In order to create this effect in a passive beam scattering system, a variety of components must operate in conjunction to produce the desired beam parameters. We will describe how the SOBP is generated and will explore the tolerances of the various components and their subsequent effect on the dose distribution. A specific aspect of this investigation includes a case study involving the use of a beam current modulated system. In such a system, the intensity of the beam current can be varied in synchronization with the revolution of the range-modulator wheel. As a result, the weights of the pulled-back Bragg peaks can be individually controlled to produce uniform dose plateaus for a large range of treatment depths using only a small number of modulator wheels. PMID:17985630

  9. Sensitivities in the production of spread-out Bragg peak dose distributions by passive scattering with beam current modulation

    SciTech Connect

    Lu, H.-M.; Brett, Robert; Engelsman, Martijn; Slopsema, Roelf; Kooy, Hanne; Flanz, Jay

    2007-10-15

    A spread-out Bragg peak (SOBP) is used in proton beam therapy to create a longitudinal conformality of the required dose to the target. In order to create this effect in a passive beam scattering system, a variety of components must operate in conjunction to produce the desired beam parameters. We will describe how the SOBP is generated and will explore the tolerances of the various components and their subsequent effect on the dose distribution. A specific aspect of this investigation includes a case study involving the use of a beam current modulated system. In such a system, the intensity of the beam current can be varied in synchronization with the revolution of the range-modulator wheel. As a result, the weights of the pulled-back Bragg peaks can be individually controlled to produce uniform dose plateaus for a large range of treatment depths using only a small number of modulator wheels.

  10. Parton distributions extracted from data on deep-inelastic lepton scattering, prompt photon production, and the Drell-Yan process

    NASA Astrophysics Data System (ADS)

    Harriman, P. N.; Martin, A. D.; Stirling, W. J.; Roberts, R. G.

    1990-08-01

    We present a next-to-leading-order QCD structure-function analysis of deep-inelastic muon and neutrino scattering data. In particular, we incorporate new F?n2/F?p2 data and take account of a recent reanalysis of SLAC data. The fit is performed simultaneously with next-to-leading-order fits to recent prompt photon and Drell-Yan data. As a result we are able to place tighter constraints on the quark and gluon distributions. Two definitive sets of parton distributions are presented according to whether the European Muon Collaboration or Bologna-CERN-Dubna-Munich-Saclay Collaboration muon data are included in the global fit. Comparisons with distributions obtained in earlier analyses are made and the consistency of data sets is investigated.

  11. A Tariff for Reactive Power

    SciTech Connect

    Kueck, John D; Kirby, Brendan J; Li, Fangxing; Tufon, Christopher; Isemonger, Alan

    2008-07-01

    Two kinds of power are required to operate an electric power system: real power, measured in watts, and reactive power, measured in volt-amperes reactive or VARs. Reactive power supply is one of a class of power system reliability services collectively known as ancillary services, and is essential for the reliable operation of the bulk power system. Reactive power flows when current leads or lags behind voltage. Typically, the current in a distribution system lags behind voltage because of inductive loads such as motors. Reactive power flow wastes energy and capacity and causes voltage droop. To correct lagging power flow, leading reactive power (current leading voltage) is supplied to bring the current into phase with voltage. When the current is in phase with voltage, there is a reduction in system losses, an increase in system capacity, and a rise in voltage. Reactive power can be supplied from either static or dynamic VAR sources. Static sources are typically transmission and distribution equipment, such as capacitors at substations, and their cost has historically been included in the revenue requirement of the transmission operator (TO), and recovered through cost-of-service rates. By contrast, dynamic sources are typically generators capable of producing variable levels of reactive power by automatically controlling the generator to regulate voltage. Transmission system devices such as synchronous condensers can also provide dynamic reactive power. A class of solid state devices (called flexible AC transmission system devices or FACTs) can provide dynamic reactive power. One specific device has the unfortunate name of static VAR compensator (SVC), where 'static' refers to the solid state nature of the device (it does not include rotating equipment) and not to the production of static reactive power. Dynamic sources at the distribution level, while more costly would be very useful in helping to regulate local voltage. Local voltage regulation would reduce system losses, increase circuit capacity, increase reliability, and improve efficiency. Reactive power is theoretically available from any inverter-based equipment such as photovoltaic (PV) systems, fuel cells, microturbines, and adjustable-speed drives. However, the installation is usually only economical if reactive power supply is considered during the design and construction phase. In this report, we find that if the inverters of PV systems or the generators of combined heat and power (CHP) systems were designed with capability to supply dynamic reactive power, they could do this quite economically. In fact, on an annualized basis, these inverters and generators may be able to supply dynamic reactive power for about $5 or $6 per kVAR. The savings from the local supply of dynamic reactive power would be in reduced losses, increased capacity, and decreased transmission congestion. The net savings are estimated to be about $7 per kVAR on an annualized basis for a hypothetical circuit. Thus the distribution company could economically purchase a dynamic reactive power service from customers for perhaps $6/kVAR. This practice would provide for better voltage regulation in the distribution system and would provide an alternate revenue source to help amortize the cost of PV and CHP installations. As distribution and transmission systems are operated under rising levels of stress, the value of local dynamic reactive supply is expected to grow. Also, large power inverters, in the range of 500 kW to 1 MW, are expected to decrease in cost as they become mass produced. This report provides one data point which shows that the local supply of dynamic reactive power is marginally profitable at present for a hypothetical circuit. We expect that the trends of growing power flow on the existing system and mass production of inverters for distributed energy devices will make the dynamic supply of reactive power from customers an integral component of economical and reliable system operation in the future.

  12. Reactive arthritis.

    PubMed

    Stavropoulos, P G; Soura, E; Kanelleas, A; Katsambas, A; Antoniou, C

    2015-03-01

    Reactive arthritis (ReA) is an immune-mediated seronegative arthritis that belongs to the group of spondyloarthropathies and develops after a gastrointestinal or genitourinary system infection. The condition is considered to be characterized by a triad of symptoms (conjunctivitis, arthritis and urethritis) although a constellation of other manifestations may also be present. ReA is characterized by psoriasiform dermatological manifestations that may resemble those of pustular psoriasis and, similar to guttate psoriasis, is a post-infectious entity. Also, the articular manifestations of the disorder are similar to those of psoriatic arthritis and both conditions show a correlation with HLA-B27. These facts have led several authors to suggest that there is a connection between ReA and psoriasis, listing ReA among the disorders related to psoriasis. However, the pathogenetic mechanism behind the condition is complex and poorly understood. Bacterial antigenicity, the type of host response (i.e. Th1/Th2 imbalance) and various genetic factors (i.e. HLA-B27 etc.) play an important role in the development of the disorder. It is unknown whether all the aforementioned factors are part of a mechanism that could be similar to, or share basic aspects with known psoriasis pathogenesis mechanisms. PMID:25199646

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

    NASA Astrophysics Data System (ADS)

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

    1999-04-01

    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 μm and 4 μm 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.

  14. Receptor for advanced glycation end products involved in circulating endothelial cells release from human coronary endothelial cells induced by C-reactive protein

    PubMed Central

    Zhou, Shulai; Gao, Lichao; Gong, Fangqi; Chen, Xiaoyang

    2015-01-01

    Objective(s): This study was designed to investigate the effect of receptor for advanced glycation end products (RAGE), S100A12 and C-reactive protein (CRP) on the release of circulating endothelial cells (CECs) from human coronary artery endothelial cells (HCAECs). Materials and Methods: HCAECs were cultured in increasing concentration of CRP (0, 12.5, 25, 50?g/ml) or S100A12 protein (0, 4, 10, 25?g/ml) for 24 hr. CECs were measured by flow cytometry. Small interfering RNA (siRNA) was designed to decrease RAGE level. Fluorescence microscopy and real-time quantitative polymerase chain reaction were used to assess the efficiency of siRNA silencing RAGE. The release of CECs from HCAECs was further evaluated by flow cytometry. Results: CRP caused a significant increase in the release of CECs from HCAECs. The number of CECs increased by about 2-fold in 25 ?g/ml CRP-treated group compared to the control group (12.22% compared to 6.82%, P=0.032). But S100A12 failed to increase the release of CECs from HCAECs. Blockade of RAGE by siRNA significantly decreased the release of CECs induced by CRP (13.22% of CRP group compared to 8.77% of CRP+siRNA group, P=0.017). Conclusion: RAGE is involved in the release of CECs induced by CRP, and the effect can be attenuated by silencing RAGE. RAGE may play an important role in endothelial dysfunction in cardiovascular disease. Inhibition of RAGE may be a therapeutic target for coronary artery lesions in Kawasaki disease. PMID:26221486

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

    SciTech Connect

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

    1989-02-01

    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.

  16. Effect of Penicillium mycotoxins on the cytokine gene expression, reactive oxygen species production, and phagocytosis of bovine macrophage (BoMacs) function.

    PubMed

    Oh, Se-Young; Mead, Philip J; Sharma, Bhawani S; Quinton, V Margaret; Boermans, Herman J; Smith, Trevor K; Swamy, H V L N; Karrow, Niel A

    2015-12-25

    Bovine macrophages (BoMacs) were exposed to the following Penicillium mycotoxins (PM): citrinin (CIT), ochratoxin A (OTA), patulin (PAT), mycophenolic acid (MPA) and penicillic acid (PA). PM exposure at the concentration that inhibits proliferation by 25% (IC25) differentially for 24h altered the gene expression of various cytokines. OTA significantly induced IL-1α expression (p<0.05), while the expression of IL-6 was suppressed (p<0.01). MPA significantly induced the expression of IL-1α (p<0.05) and reduced the expression of IL-12α (p<0.01) and IL-10 (p<0.01). PAT significantly suppressed the expression of IL-23 (p<0.01), IL-10 (p<0.05) and TGF-β (p<0.05). Some PMs also affected reactive oxygen species (ROS) and phagocytosis of Mycobacterium avium ssp. Paratuberculosis (MAP) at higher concentrations. PAT and PA for example, significantly decreased the percent phagocytosis of MAP at 5.0 (p<0.01) and 15.6μM (p<0.01), respectively, but only PA significantly suppressed PAM-3-stimulated ROS production at 62.5 (p<0.05) and 250.0μM (p<0.01). OTA significantly increased the percent phagocytosis of MAP at 6.3 (p<0.05) and 12.5μM (p<0.01). These findings suggest that exposure to sub-lethal concentrations of PMs can affect macrophage function, which could affect immunoregulation and innate disease resistance to pathogens. PMID:26394380

  17. Reactive Oxygen Species Production and Mitochondrial Dysfunction in White Blood Cells Are Not Valid Biomarkers of Ageing in the Very Old

    PubMed Central

    Wiley, Laura; Ashok, Deepthi; Martin-Ruiz, Carmen; Talbot, Duncan C. S.; Collerton, Joanna; Kingston, Andrew; Davies, Karen; Chinnery, Patrick F.; Catt, Michael; Jagger, Carol; Kirkwood, Thomas B. L.; von Zglinicki, Thomas

    2014-01-01

    Reliable and valid biomarkers of ageing (BoA) are needed to understand mechanisms, test interventions and predict the timing of adverse health events associated with ageing. Since increased reactive oxygen species (ROS) production and mitochondrial dysfunction are consequences of cellular senescence and may contribute causally to the ageing of organisms, we focused on these parameters as candidate BoA. Superoxide levels, mitochondrial mass and mitochondrial membrane potential in human peripheral blood mononuclear cells (PBMCs) and subpopulations (lymphocytes and monocytes) were measured in participants from the Newcastle 85+ study, a population-based study of the very old (aged 85 years and older). The intra- and inter-assay precision expressed as coefficient of variation (CV) for all parameters was acceptable (3% to 12% and 5 to 22% respectively). All parameters were stable in the short-term (1 week interval) in a sample of control individuals in the PBMCs and lymphocyte subpopulation, however they were unstable in the monocyte subpopulation; this rendered monocytes unreliable for further analysis. There was a significant association between superoxide levels and mitochondrial mass (positive in lymphocytes, p = 0.01) and between superoxide levels and mitochondrial membrane potential (negative in PBMCs, p = 0.01; positive in lymphocytes, p = 0.05). There were also significant associations between superoxide levels and mitochondrial parameters with other markers of oxidative stress-induced cellular senescence (p≤0.04), however some were in the opposite direction to expected. No associations were found between the measured parameters and age-related outcomes, including cognitive impairment, disability, co-morbidity and survival - questioning the validity of these parameters as candidate BoA in the very old. PMID:24614678

  18. Reactive oxygen species production and mitochondrial dysfunction in white blood cells are not valid biomarkers of ageing in the very old.

    PubMed

    Wiley, Laura; Ashok, Deepthi; Martin-Ruiz, Carmen; Talbot, Duncan C S; Collerton, Joanna; Kingston, Andrew; Davies, Karen; Chinnery, Patrick F; Catt, Michael; Jagger, Carol; Kirkwood, Thomas B L; von Zglinicki, Thomas

    2014-01-01

    Reliable and valid biomarkers of ageing (BoA) are needed to understand mechanisms, test interventions and predict the timing of adverse health events associated with ageing. Since increased reactive oxygen species (ROS) production and mitochondrial dysfunction are consequences of cellular senescence and may contribute causally to the ageing of organisms, we focused on these parameters as candidate BoA. Superoxide levels, mitochondrial mass and mitochondrial membrane potential in human peripheral blood mononuclear cells (PBMCs) and subpopulations (lymphocytes and monocytes) were measured in participants from the Newcastle 85+ study, a population-based study of the very old (aged 85 years and older). The intra- and inter-assay precision expressed as coefficient of variation (CV) for all parameters was acceptable (3% to 12% and 5 to 22% respectively). All parameters were stable in the short-term (1 week interval) in a sample of control individuals in the PBMCs and lymphocyte subpopulation, however they were unstable in the monocyte subpopulation; this rendered monocytes unreliable for further analysis. There was a significant association between superoxide levels and mitochondrial mass (positive in lymphocytes, p = 0.01) and between superoxide levels and mitochondrial membrane potential (negative in PBMCs, p = 0.01; positive in lymphocytes, p = 0.05). There were also significant associations between superoxide levels and mitochondrial parameters with other markers of oxidative stress-induced cellular senescence (p≤0.04), however some were in the opposite direction to expected. No associations were found between the measured parameters and age-related outcomes, including cognitive impairment, disability, co-morbidity and survival - questioning the validity of these parameters as candidate BoA in the very old. PMID:24614678

  19. What Is Reactive Arthritis?

    MedlinePLUS

    ... PDF Version Size: 69 KB November 2014 What is Reactive Arthritis? Fast Facts: An Easy-to-Read ... could increase the chances of getting the disease. Is Reactive Arthritis Contagious? Reactive arthritis is not contagious. ...

  20. Measurement of "pretzelosity" asymmetry of charged pion production in semi-inclusive deep inelastic scattering on a polarized 3He target

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Qian, X.; Allada, K.; Dutta, C.; Huang, J.; Katich, J.; Wang, Y.; 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, 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, M.; Ibrahim, H. F.; Iodice, M.; Jiang, X.; Jin, G.; Jones, M. K.; 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.; Muoz 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.; irca, S.; Stepanyan, S.; Subedi, R.; Sulkosky, V.; Tang, L.-G.; Tobias, W. 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.; Zong, X.; Jefferson Lab Hall A Collaboration

    2014-11-01

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

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

    NASA Astrophysics Data System (ADS)

    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.; Muoz 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.; irca, 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

    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.

  2. Single spin asymmetries in charged kaon production from semi-inclusive deep inelastic scattering on a transversely polarized He3 target

    DOE PAGESBeta

    Zhao, Y. X.; Wang, Y.; Allada, K.; Aniol, K.; Annand, J. R.M.; Averett, T.; Benmokhtar, F.; Bertozzi, W.; Bradshaw, P. C.; Bosted, P.; et al

    2014-11-03

    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 < xbj<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. Whilemore » the K+ Sivers moments are consistent with the prediction, the K– results differ from the prediction at the 2-sigma level.« less

  3. Gamma ray production cross section from energetic neutron inelastic scattering for methodical improvements in planetary gamma-ray spectroscopy

    SciTech Connect

    Castaneda, C.M.; Gearhart, R.; Sanii, B.; Englert, P.A.J.; Drake, D.M.; Reedy, R.C.

    1991-12-31

    Planetary Gamma ray spectroscopy can be used to chemically analyze the top soil from planets in future planetary missions. The production from inelastic neutron interaction plays an effective role in the determination on the C and H at the surface. The gamma ray production cross section from the strongest lines excited in the neutron bombardment of Fe have been measured by the use of a time analyzed quasi-mono-energetic neutron beam and a high purity germanium detector. The results from En=6.5, 32, 43, and 65 MeV are presented.

  4. Intrabeam scattering

    SciTech Connect

    Parzen, G.

    1988-01-01

    Intrabeam scattering is the scattering of the particles in the beam from each other through the Coulomb forces that act between each pair of particles. It depends on the ion charge and mass like Z/sup 4//A/sup 2/ and is usually larger for the heavier ions. In RHIC, extra aperture is provided to allow the beam to grow transversely because of intrabeam scattering. For Au ions, enough aperture has to be provided to allow the transverse emittances to grow by a factor of 3 over 10 hours. The beam will also grow longitudinally, and enough RF bucket area has to be provided for the longitudinal growth. For Au ions at ..gamma..=100, the beam energy spread will grow by about a factor of 3 over 10 hours. This paper discusses the concept of intrabeam scattering further. 12 figs., 1 tab.

  5. 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)

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

    2013-05-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

    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 spatiotemporal variations of pasture production at the decadal-century scales over whole watersheds are poorly known. We used a physically 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-year-long synthetic daily climate data set generated using a stochastic weather generator. The data set reproduced the range of climatic variations observed under the 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 but more interannual variability. 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.

  7. Measurement of the nu(mu) Charged Current pi+ Production to Quasi-elastic Scattering Cross Section

    SciTech Connect

    Nowak, Jaroslaw A.; /Louisiana State U.

    2009-09-01

    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.

  8. Phenylethynyl endcapping reagents and reactive diluents

    NASA Technical Reports Server (NTRS)

    Jensen, Brian J. (inventor); Bryant, Robert G. (inventor); Hergenrother, Paul M. (inventor)

    1994-01-01

    A phenylethynyl composition which can be used to endcap nucleophilic species is employed in the production of phenylethynyl terminated reactive oligomers exclusively. These phenylethynyl terminated reactive oligomers display unique thermal characteristics, as exemplified by the model compound, 4-phenoxy 4'-phenylethynylbenzophenone, which is relatively stable at 200 C, but reacts at 350 C. In addition, a reactive diluent was prepared which decreases the melt viscosity of the phenylethynyl terminated oligomers and subsequently reacts therewith to increase density of the resulting thermoset. The novelty of this invention resides in the phenylethynyl composition used to terminate a nucleophilic reagent, resulting in the exclusive production of phenylethynyl terminated reactive oligomers which display unique thermal characteristics. A reactive diluent was also employed to decrease the melt viscosity of a phenylethynyl terminated reactive oligomer and to subsequently react therewith to increase the crosslink density of the resulting thermoset. These materials have features which make them attractive candidates for use as composite matrices and adhesives.

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

    PubMed

    Glossman-Mitnik, Daniel

    2014-07-01

    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

  10. 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)

    Blobaum, Kerri Jayne

    2002-09-01

    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/moleatom, 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.

  11. Dynamics of inelastic and reactive gas-surface collisions

    SciTech Connect

    Smoliar, L.A.

    1995-04-01

    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.

  12. Production of Nurr-1 Specific Polyclonal Antibodies Free of Cross-reactivity Against Its Close Homologs, Nor1 and Nur77

    PubMed Central

    Leblanc, Pierre; Moon, Minho; Kim, Woori; Jeong, Inhye; Kim, Chun-Hyung; Kim, Kwang-Soo

    2016-01-01

    The nuclear receptor subfamily 4 (NR4A) is composed of 3 related proteins sharing a DNA binding domain (DBD) and a ligand-binding domain (LBD). The nuclear receptor related 1 protein (Nurr1 or NR4A2) plays a key role in the maintenance of the dopaminergic system. Dopamine dysfunctions associated with the Nurr1 gene include Parkinson's disease, schizophrenia and manic depression among others. Furthermore, recent evidence indicates that Nurr1 is also expressed in other brain areas such as the hippocampus and plays critical roles for learning and memory. The other members of the family are nerve growth factor IB (Nur77 or NR4A1) and neuron-derived orphan receptor 1 (NOR1 or NR4A3). To help investigate the precise functional roles of Nurr1 in dopaminergic and other brain region-related neuronal dysfunctions antibodies devoid of cross-reactivities against Nur77 and NOR1 were needed. Since the proteins are more divergent in their LBDs than in their DNA binding domains immunization with purified LBDs should yield antibodies specific for Nurr1 with minimal reactivities against Nur77 and/or NOR1. Although anti-Nurr1 antibodies were successfully generated these showed significant immunoreactivity against the other members of the family. Affinity chromatography over immobilized Protein A followed by pre-adsorption against immobilized Nur77 and NOR1 LBDs yielded Nurr1 specific antibodies free of cross-reactivity. Here, we selectively target antibodies against a specific member of a highly conserved family of proteins by immunizing animals with their most divergent regions followed by removing cross reactive antibodies by pre-adsorption. The goal of the protocol is to increase polyclonal antibodies specificity through pre-adsorption against cross-reactive antigens. PMID:26325389

  13. B cell response and hemagglutinin stalk-reactive antibody production in different age cohorts following 2009 H1N1 influenza virus vaccination.

    PubMed

    Sangster, Mark Y; Baer, Jane; Santiago, Felix W; Fitzgerald, Theresa; Ilyushina, Natalia A; Sundararajan, Aarthi; Henn, Alicia D; Krammer, Florian; Yang, Hongmei; Luke, Catherine J; Zand, Martin S; Wright, Peter F; Treanor, John J; Topham, David J; Subbarao, Kanta

    2013-06-01

    The 2009 pandemic H1N1 (pH1N1) influenza virus carried a swine-origin hemagglutinin (HA) that was closely related to the HAs of pre-1947 H1N1 viruses but highly divergent from the HAs of recently circulating H1N1 strains. Consequently, prior exposure to pH1N1-like viruses was mostly limited to individuals over the age of about 60 years. We related age and associated differences in immune history to the B cell response to an inactivated monovalent pH1N1 vaccine given intramuscularly to subjects in three age cohorts: 18 to 32 years, 60 to 69 years, and ≥70 years. The day 0 pH1N1-specific hemagglutination inhibition (HAI) and microneutralization (MN) titers were generally higher in the older cohorts, consistent with greater prevaccination exposure to pH1N1-like viruses. Most subjects in each cohort responded well to vaccination, with early formation of circulating virus-specific antibody (Ab)-secreting cells and ≥4-fold increases in HAI and MN titers. However, the response was strongest in the 18- to 32-year cohort. Circulating levels of HA stalk-reactive Abs were increased after vaccination, especially in the 18- to 32-year cohort, raising the possibility of elevated levels of cross-reactive neutralizing Abs. In the young cohort, an increase in MN activity against the seasonal influenza virus A/Brisbane/59/07 after vaccination was generally associated with an increase in the anti-Brisbane/59/07 HAI titer, suggesting an effect mediated primarily by HA head-reactive rather than stalk-reactive Abs. Our findings support recent proposals that immunization with a relatively novel HA favors the induction of Abs against conserved epitopes. They also emphasize the need to clarify how the level of circulating stalk-reactive Abs relates to resistance to influenza. PMID:23576673

  14. Measurement of beauty and charm production in deep inelastic scattering at HERA and measurement of the beauty-quark mass

    NASA Astrophysics Data System (ADS)

    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.; Ktz, U.; Kovalchuk, N.; Kowalski, H.; Kuprash, O.; Kuze, M.; Levchenko, B. B.; Levy, A.; Libov, V.; Limentani, S.; Lisovyi, M.; Lobodzinska, E.; Lohmann, W.; Lhr, 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.; Schrner-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

    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.

  15. Measurement of beauty and charm production in deep inelastic scattering at HERA and measurement of the beauty-quark mass

    NASA Astrophysics Data System (ADS)

    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.; Ktz, U.; Kovalchuk, N.; Kowalski, H.; Kuprash, O.; Kuze, M.; Levchenko, B. B.; Levy, A.; Libov, V.; Limentani, S.; Lisovyi, M.; Lobodzinska, E.; Lohmann, W.; Lhr, 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.; Schrner-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.

    2014-10-01

    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.

  16. Patterned retarder films using reactive mesogen technology

    NASA Astrophysics Data System (ADS)

    Parri, Owain; Smith, Graham; Harding, Richard; Yoon, Hyun-Jin; Gardiner, Iain; Sargent, Joe; Skjonnemand, Karl

    2011-03-01

    A range of polymerisable liquid crystals mixtures have been developed (so called, Reactive Mesogen) that are ideally suited for the fabrication of patterned retarder films. Such films, made using a combination of Merck Reactive Mesogen Mixtures coated on a plastic substrate containing a photoalignment layer, are commercially employed to produce 3D displays. Different methods of patterning Reactive Mesogen Mixtures are discussed and the merits of each considered. Although the first commercial products use normal dispersion Reactive Mesogen Materials, the advantages of using the next generation of materials, which have improved wavelength dispersion, are introduced with a focus on their use in 3D patterned retarder films.

  17. Method for reactivating solid catalysts used in alkylation reactions

    DOEpatents

    Ginosar, Daniel M.; Thompson, David N.; Coates, Kyle; Zalewski, David J.; Fox, Robert V.

    2003-06-17

    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.

  18. Method For Reactivating Solid Catalysts Used For Alklation Reactions

    DOEpatents

    Ginosar, Daniel M.; Thompson, David N.; Coates, Kyle; Zalewski, David J.; Fox, Robert V.

    2005-05-03

    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.

  19. 2,3,7,8-Tetrachlorodibenzo-p-dioxin increases reactive oxygen species production in human endothelial cells via induction of cytochrome P4501A1

    SciTech Connect

    Kopf, P.G.; Walker, M.K.

    2010-05-15

    Studies in our laboratory have demonstrated that subchronic 2,3,7,8,-tetrachlorodibenzo-p-dioxin (TCDD) exposure of adult mice results in hypertension, cardiac hypertrophy, and reduced nitric oxide (NO)-mediated vasodilation. Moreover, increased superoxide anion production was observed in cardiovascular organs of TCDD-exposed mice and this increase contributed to the reduced NO-mediated vasodilation. Since cytochrome P4501A1 (CYP1A1) can contribute to some TCDD-induced toxicity, we tested the hypothesis that TCDD increases reactive oxygen species (ROS) in endothelial cells by the induction of CYP1A1. A concentration-response to 24 h TCDD exposure (10 pM-10 nM) was performed in confluent primary human aortic endothelial cells (HAECs). Oxidant-sensitive fluorescent probes dihydroethidium (DHE) and 2',7'-dichlorofluorescin diacetate (DCFH-DA), were used to measure superoxide anion, and hydrogen peroxide and hydroxyl radical, respectively. NO was also measured using the fluorescent probe diaminofluorescein-2 diacetate (DAF-2DA). These assessments were conducted in HAECs transfected with siRNA targeting the aryl hydrocarbon receptor (AhR), CYP1A1, or CYP1B1. TCDD concentration-dependently increased CYP1A1 and CYP1B1 mRNA, protein, and enzyme activity. Moreover, 1 nM TCDD maximally increased DHE (Cont = 1.0 +- 0.3; TCDD = 5.1 +- 1.0; p = 0.002) and DCFH-DA (Cont = 1.0 +- 0.2; TCDD = 4.1 +- 0.5; p = 0.002) fluorescence and maximally decreased DAF-2DA fluorescence (Cont = 1.0 +- 0.4; TCDD = 0.68 +- 0.1). siRNA targeting AhR and CYP1A1 significantly decreased TCDD-induced DHE (siAhR: Cont = 1.0 +- 0.1; TCDD = 1.3 +- 0.2; p = 0.093) (siCYP1A1: Cont = 1.0 +- 0.1; TCDD = 1.1 +- 0.1; p = 0.454) and DCFH-DA (siAhR: Cont = 1.0 +- 0.2; TCDD = 1.3 +- 0.3; p = 0.370) (siCYP1A1: Cont = 1.0 +- 0.1; TCDD = 1.3 +- 0.2; p = 0.114) fluorescence and increased DAF-2DA fluorescence (siAhR: Cont = 1.00 +- 0.03; TCDD = 0.97 +- 0.03; p = 0.481) (siCYP1A1: Cont = 1.00 +- 0.03; TCDD = 0.92 +- 0.03; p = 0.034), while siRNA targeting CYP1B1 did not. These data suggest that TCDD-induced increase in ROS is AhR-dependent and may be mediated, in part, by CYP1A1 induction.

  20. System for reactivating catalysts

    SciTech Connect

    Ginosar, Daniel M.; Thompson, David N.; Anderson, Raymond P.

    2010-03-02

    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.

  1. Reactive Arthritis Diagnosis

    MedlinePLUS

    ... AS / Low Starch Diet Blood Work and Spondylitis Reactive Arthritis Symptoms Because there is no specific laboratory test for reactive arthritis, doctors sometimes find it difficult to diagnose. As ...

  2. Studies of coal reactivity for direct liquefaction

    SciTech Connect

    Stephens, H.P.; Kottenstette, R.J.

    1990-01-01

    This paper presents a preliminary report on a continuing effort to quantify the reactivity of coal for direct liquefaction reactions in terms of the utilization of hydrogen, the selectivity to products and the properties of the products formed. Liquefaction processes are aimed at maximizing the yield of distillate that can serve as hydrocarbon fuels and chemical feedstocks. This study seeks to better describe: (1) how hydrogen consumed during liquefaction is distributed among product groups; (2) coal reactivity in terms of a relationship defining the selectivity to products formed during liquefaction; and (3) the relation of coal structure to reactivity for liquefaction reactions. Because of the limited space for reporting this effort in this special edition of Fuel, the experimental methods, calculations and data are presented in abbreviated form in order to focus on interpretation and discussion of the results in terms of coal structure and reactivity. 30 refs., 3 figs., 2 tabs.

  3. The production, localization and spreading of reactive oxygen species contributes to the low vitality of long-term stored common beech (Fagus sylvatica L.) seeds.

    PubMed

    Ratajczak, Ewelina; Ma?ecka, Arleta; Bagniewska-Zadworna, Agnieszka; Kalemba, Ewa Marzena

    2015-02-01

    The common beech (Fagus sylvatica L.) is propagated by seeds, but the seed set is irregular with five to ten years in between crops. It is therefore necessary to store the seeds. However, beech seeds lose germinability during long-term storage. In this study, beech seeds were stored at -10C under controlled conditions for 2, 5, 8, 11 and 13 years. Our results show that beech seeds lose germinability during storage in proportion to the duration of storage. The decrease in germinability correlated with increased electrolyte leakage and accumulation of superoxide anion radicals, hydrogen peroxide and hydroxyl radicals. Furthermore, a strong positive correlation was observed among the releases of superoxide anion radicals, hydrogen peroxide and hydroxyl radicals. In situ localization showed that superoxide anion radicals and hydrogen peroxide were first detectable in root cap cells. When the seed storage time was extended, the reactive oxygen species fluorescence expanded to more areas of the radicle, reaching the root apical meristem. A storage time-dependent decrease in catalase activity, observed in both embryonic axes and cotyledons, was also positively correlated with germinability. DNA fragmentation was observed in beech seeds during storage and occurred predominantly in embryonic axes stored for 5 years and more. Altogether, these results suggest that the loss of germinability in beech seeds during long-term storage depends on several factors, including strong of reactive oxygen species accumulation accompanied by reduced catalase activity as well as membrane injury and DNA alternations, which may be aging-related and ROS-derived. We suggest that the accumulating reactive oxygen species that spread to the root apical meristem are key factors that affect seed germinability after long-term storage. PMID:25462977

  4. 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

    Haanwinckel, Maria Cristina Santos; de Oliveira, Silvio Luis

    2011-01-01

    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

  5. Production of serum amyloid A and C-reactive protein by HepG2 cells stimulated with combinations of cytokines or monocyte conditioned media: the effects of prednisolone.

    PubMed Central

    Smith, J W; McDonald, T L

    1992-01-01

    The hepatic production of the acute phase proteins in response to inflammatory cytokines, and the interaction of corticosteroids within this response, has been the subject of considerable recent research. In this study we have examined the effects of the corticosteroid prednisolone on the production of IL-1 alpha and IL-1 beta by lipopolysaccharide (LPS)-stimulated monocytes, and the ability of the monocyte conditioned media (MOCM) obtained under these conditions to induce human hepatoma HepG2 cells to produce serum amyloid A (SAA) and C-reactive protein (CRP). We also examined the production of SAA and CRP by HepG2 cells exposed to different combinations and concentrations of recombinant human (rh) IL-1 alpha, rhIL-1 beta, rhIL-6, recombinant human tumour necrosis factor-alpha (rhTNF-alpha) and prednisolone. The findings indicate: (i) prednisolone substantially inhibits the production of both IL-1 alpha and IL-1 beta by LPS-stimulated monocytes. The MOCM from prednisolone-treated monocytes induced less SAA and CRP production by HepG2 cells; (ii) IL-1 alpha and IL-1 beta both induced CRP and SAA synthesis by HepG2 cells, but only in the presence of IL-6. IL-1 beta was the more potent inducer for SAA production, but for CRP production IL-1 alpha and IL-1 beta were equivalent; (iii) prednisolone enhances the production of SAA by HepG2 cells, but does not enhance the production of CRP; (iv) TNF-alpha in the presence or absence of IL-6 and/or prednisolone did not induce the production of SAA or CRP by HepG2 cells. These findings offer a tenable solution to a disparate production of SAA compared with CRP in corticosteroid-treated cystic fibrosis (CF) patients. PMID:1424289

  6. Meaurement of D{sup *}{sup plus_minus} production in deep inelastic e{sup plus_minus}p scattering at HERA.

    SciTech Connect

    Chekanov, S.; Derrick, M.; Krakauer, D.; Loizides, J. H.; Magill, S.; Musgrave, B.; Repond, J.; Yoshida, R.; ZEUS Collaboration; High Energy Physics

    2004-01-01

    Inclusive production of D{sup *}{sup {+-}} (2010) mesons in deep inelastic scattering has been measured with the ZEUS detector at DESY HERA using an integrated luminosity of 81.9 pb{sup -1}. The decay channel D{sup *}{sup +}{yields}D0{pi}{sup +} with D0{yields}K-{pi}{sup +} and corresponding antiparticle decay were used to identify D{sup *} mesons. Differential D{sup *} cross sections with 1.5

  7. Analysis of reactive bromine production and ozone depletion in the Arctic boundary layer using 3-D simulations with GEM-AQ: inference from synoptic-scale patterns

    NASA Astrophysics Data System (ADS)

    Toyota, K.; McConnell, J. C.; Lupu, A.; Neary, L.; McLinden, C. A.; Richter, A.; Kwok, R.; Semeniuk, K.; Kaminski, J. W.; Gong, S.-L.; Jarosz, J.; Chipperfield, M. P.; Sioris, C. E.

    2011-04-01

    Episodes of high bromine levels and surface ozone depletion in the springtime Arctic are simulated by an online air-quality model, GEM-AQ, with gas-phase and heterogeneous reactions of inorganic bromine species and a simple scheme of air-snowpack chemical interactions implemented for this study. Snowpack on sea ice is assumed to be the only source of bromine to the atmosphere and to be capable of converting relatively stable bromine species to photolabile Br2 via air-snowpack interactions. A set of sensitivity model runs are performed for April 2001 at a horizontal resolution of approximately 100 km100 km in the Arctic, to provide insights into the effects of temperature and the age (first-year, FY, versus multi-year, MY) of sea ice on the release of reactive bromine to the atmosphere. The model simulations capture much of the temporal variations in surface ozone mixing ratios as observed at stations in the high Arctic and the synoptic-scale evolution of areas with enhanced BrO column amount ("BrO clouds") as estimated from satellite observations. The simulated "BrO clouds" are in modestly better agreement with the satellite measurements when the FY sea ice is assumed to be more efficient at releasing reactive bromine to the atmosphere than on the MY sea ice. Surface ozone data from coastal stations used in this study are not sufficient to evaluate unambiguously the difference between the FY sea ice and the MY sea ice as a source of bromine. The results strongly suggest that reactive bromine is released ubiquitously from the snow on the sea ice during the Arctic spring while the timing and location of the bromine release are largely controlled by meteorological factors. It appears that a rapid advection and an enhanced turbulent diffusion associated with strong boundary-layer winds drive transport and dispersion of ozone to the near-surface air over the sea ice, increasing the oxidation rate of bromide (Br-) in the surface snow. Also, if indeed the surface snowpack does supply most of the reactive bromine in the Arctic boundary layer, it appears to be capable of releasing reactive bromine at temperatures as high as -10 C, particularly on the sea ice in the central and eastern Arctic Ocean. Dynamically-induced BrO column variability in the lowermost stratosphere appears to interfere with the use of satellite BrO column measurements for interpreting BrO variability in the lower troposphere but probably not to the extent of totally obscuring "BrO clouds" that originate from the surface snow/ice source of bromine in the high Arctic. A budget analysis of the simulated air-surface exchange of bromine compounds suggests that a "bromine explosion" occurs in the interstitial air of the snowpack and/or is accelerated by heterogeneous reactions on the surface of wind-blown snow in ambient air, both of which are not represented explicitly in our simple model but could have been approximated by a parameter adjustment for the yield of Br2 from the trigger.

  8. 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...

  9. Laws of Scattering Applied to Popular Music.

    ERIC Educational Resources Information Center

    Cook, Kevin L.

    1989-01-01

    Describes a study that examined Top 40 singles chart data to determine whether the frequency distribution of artist productivity fit either of two laws of scatter (Lotka Law of Scientific Productivity or Bradford Law of Scatter). Possible reasons for the lack of statistical significance found between the theoretical and observed distributions are