These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Reactive scattering of F+HD-->HF(v,J)+D: HF(v,J) nascent product state distributions and evidence for quantum transition state resonances  

NASA Astrophysics Data System (ADS)

Single collision reactive scattering dynamics of F+HD?HF(v,J)+D have been investigated exploiting high-resolution (???0.0001 cm-1) infrared laser absorption for quantum state resolved detection of nascent HF(v,J) product states. State resolved Doppler profiles are recorded for a series of HF rovibrational transitions and converted into state resolved fluxes via density-to-flux analysis, yielding cross-section data for relative formation of HF(v,J) at Ecom?0.6(2), 1.0(3), 1.5(3), and 1.9(4) kcal/mol. State resolved HF(v,J) products at all but the lowest collision energy exhibit Boltzmann-type populations, characteristic of direct reactive scattering dynamics. At the lowest collision energy [Ecom?0.6(2) kcal/mol], however, the HF(v=2,J) populations behave quite anomalously, exhibiting a nearly "flat" distribution out to J?11 before dropping rapidly to zero at the energetic limit. These results provide strong experimental support for quantum transition state resonance dynamics near Ecom?0.6 kcal/mol corresponding classically to H atom chattering between the F and D atoms, and prove to be in remarkably quantitative agreement with theoretical wave packet predictions by Skodje et al. [J. Chem. Phys. 112, 4536 (2000)]. These fully quantum state resolved studies therefore nicely complement the recent crossed beam studies of Dong et al. [J. Chem. Phys. 113, 3633 (2000)], which confirm the presence of this resonance via angle resolved differential cross-section measurements. The observed quantum state distributions near threshold also indicate several rotational states in the HF(v=3) vibrational manifold energetically inaccessible to F(2P3/2) reagent, but which are consistent with a minor (?5%) nonadiabatic contribution from spin-orbit excited F*(2P1/2).

Harper, Warren W.; Nizkorodov, Sergey A.; Nesbitt, David J.

2002-04-01

2

Reactive scattering of alkali dimers: Apparatus and experimental conditions  

Microsoft Academic Search

The design and construction of a molecular beam machine to study reactive scattering of a magnetically purified alkali dimer beam is described. Magnetic deflection measurements of a potassium nozzle beam indicate that ?25 mole per cent K2 dimer is formed in the Laval expansion and that magnetic deflection reduces K atom impurity <10 mole per cent in the final K2

P. B. Foreman; G. M. Kendall; R. Grice

1972-01-01

3

Reactive scattering of alkali dimers: Apparatus and experimental conditions  

Microsoft Academic Search

The design and construction of a molecular beam machine to study reactive scattering of a magnetically purified alkali dimer beam is described. Magnetic deflection measurements of a potassium nozzle beam indicate that ˜25 mole per cent K2 dimer is formed in the Laval expansion and that magnetic deflection reduces K atom impurity <10 mole per cent in the final K2

P. B. Foreman; G. M. Kendall; R. Grice

1972-01-01

4

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

SciTech Connect

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.

Lykke, K.R. (Argonne National Lab., IL (USA)); Kay, B.D. (Sandia National Labs., Albuquerque, NM (USA))

1990-01-01

5

Inelastic and reactive scattering of hyperthermal atomic oxygen from amorphous carbon  

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

6

Theoretical Studies of Direct and Resonant Reactive Scattering Involving Three-Body Systems  

Microsoft Academic Search

The validity of DWBA method is checked to study the direct process for atom-diatomic molecule collisions. The DWBA results for the relative product rotational state distribution for H + D_2 to HD + D are demonstrated to be in good agreement with experimental observations and quasi-classical calculations. Direct comparison between the DWBA and exact close-coupling calculations for the reactive scattering

Chen Kwee Lutrus

1988-01-01

7

Reactive Phosphorus Removal from Aquaculture and Poultry Productions  

E-print Network

Reactive Phosphorus Removal from Aquaculture and Poultry Productions Systems Using Polymeric of a sorption processes for the ultimate removal and recovery of reactive phos- phorus from aquaculture poultry and aquaculture wastewater effluents. Upon treatment, phosphorus anion concentrations were reduced

Rubloff, Gary W.

8

Characterization of corrosion products in the permeable reactive barriers  

Microsoft Academic Search

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

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

2000-01-01

9

Modern integral equation techniques for quantum reactive scattering theory  

SciTech Connect

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

Auerbach, S.M.

1993-11-01

10

Inelastic and Reactive Scattering Dynamics of Hyperthermal Oxygen Atoms on Ionic Liquid Surfaces: [emim][NTf{sub 2}] and [C{sub 12}mim][NTf{sub 2}  

SciTech Connect

Collisions of hyperthermal oxygen atoms, with an average translational energy of 520 kJ mol{sup -1}, on continuously refreshed ionic liquids, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([emim][NTf{sub 2}]) and 1-dodecyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([C{sub 12}mim][NTf{sub 2}]), were studied with the use of a beam-surface scattering technique. Time-of-flight and angular distributions of inelastically scattered O and reactively scattered OH and H{sub 2}O were collected for various angles of incidence with the use of a rotatable mass spectrometer detector. For both O and OH, two distinct scattering processes were identified, which can be empirically categorized as thermal and non-thermal. Non-thermal scattering is more probable for both O and OH products. The observation of OH confirms that at least some reactive sites, presumably alkyl groups, must be exposed at the surface. The ionic liquid with the longer alkyl chain, [C{sub 12}mim][NTf{sub 2}], is substantially more reactive than the liquid with the shorter alkyl chain, [emim][NTf{sub 2}], and proportionately much more so than would be predicted simply from stoichiometry based on the number of abstractable hydrogen atoms. Molecular dynamics models of these surfaces shed light on this change in reactivity. The scattering behavior of O is distinctly different from that of OH. However, no such differences between inelastic and reactive scattering dynamics have been seen in previous work on pure hydrocarbon liquids, in particular the benchmark, partially branched hydrocarbon, squalane (C{sub 30}H{sub 62}). The comparison between inelastic and reactive scattering dynamics indicates that inelastic scattering from the ionic liquid surfaces takes place predominantly at non-reactive sites that are effectively stiffer than the reactive alkyl chains, with a higher proportion of collisions sampling such sites for [emim][NTf{sub 2}] than for [C{sub 12}mim][NTf{sub 2}].

Wu Bohan; Zhang Jianming; Minton, Timothy K. [Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717 (United States); McKendrick, Kenneth G. [School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Slattery, John M. [Department of Chemistry, University of York, Heslington, York YO10 5DD (United Kingdom); Yockel, Scott; Schatz, George C. [Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113 (United States)

2011-05-20

11

Electroweak boson production in double parton scattering  

NASA Astrophysics Data System (ADS)

We study the W+W- and Z0Z0 electroweak boson production in double parton scattering using QCD evolution equations for double parton distributions. In particular, we analyze the impact of splitting terms in the evolution equations on the double parton scattering cross sections. Unlike the standard terms, the splitting terms are not suppressed for large values of the relative momentum of two partons in the double parton scattering. Thus, they play an important role which we discuss in detail for the single splitting contribution to the cross sections under the study.

Golec-Biernat, Krzysztof; Lewandowska, Emilia

2014-11-01

12

Production of reactive sintered nickel aluminide  

SciTech Connect

This is the final report pertaining to the development of aluminides by reactive synthesis. Included in this report is an overview of results during the scope of this effort, details on specific task accomplishments, and a summary of customer evaluations. Opportunities for future work are also included at the end of this report.

NONE

1995-10-01

13

The k-j-j' vector correlation in inelastic and reactive scattering.  

PubMed

Quasi-classical trajectory (QCT) methods are presented which allow characterization of the angular momentum depolarization of the products of inelastic and reactive scattering. The particular emphasis of the theory is on three-vector correlations, and on the connection with the two-vector correlation between the initial and final angular momenta, j and j', which is amenable to experimental measurement. The formal classical theory is presented, and computational results for NO(A) + He are used to illustrate the type of mechanistic information provided by analysis of the two- and three-vector correlations. The classical j-j' two-vector correlation results are compared with quantum mechanical calculations, and are shown to be in good agreement. The data for NO(A) + He support previous conclusions [M. Brouard, H. Chadwick, Y.-P. Chang, R. Cireasa, C. J. Eyles, A. O. L. Via, N. Screen, F. J. Aoiz, and J. K?os, J. Chem. Phys. 131, 104307 (2009)] that this system is only weakly depolarizing. Furthermore, it is shown that the projection of j along the kinematic apse is nearly conserved for this system under thermal collision energy conditions. PMID:21895183

Brouard, M; Chadwick, H; Eyles, C J; Aoiz, F J; K?os, J

2011-08-28

14

The k-j-j' vector correlation in inelastic and reactive scattering  

NASA Astrophysics Data System (ADS)

Quasi-classical trajectory (QCT) methods are presented which allow characterization of the angular momentum depolarization of the products of inelastic and reactive scattering. The particular emphasis of the theory is on three-vector correlations, and on the connection with the two-vector correlation between the initial and final angular momenta, j and j^' }, which is amenable to experimental measurement. The formal classical theory is presented, and computational results for NO(A) + He are used to illustrate the type of mechanistic information provided by analysis of the two- and three-vector correlations. The classical j-j^' } two-vector correlation results are compared with quantum mechanical calculations, and are shown to be in good agreement. The data for NO(A) + He support previous conclusions [M. Brouard, H. Chadwick, Y.-P. Chang, R. Cireasa, C. J. Eyles, A. O. L. Via, N. Screen, F. J. Aoiz, and J. K?os, J. Chem. Phys. 131, 104307 (2009)], 10.1063/1.3212608 that this system is only weakly depolarizing. Furthermore, it is shown that the projection of j along the kinematic apse is nearly conserved for this system under thermal collision energy conditions.

Brouard, M.; Chadwick, H.; Eyles, C. J.; Aoiz, F. J.; K?os, J.

2011-08-01

15

Quantum reactive scattering calculations of photodetachment spectra of the FHD - anion  

NASA Astrophysics Data System (ADS)

Time-independent quantum reactive scattering calculations have been carried out to simulate the photoelectron spectrum of the FHD - anion using the accurate ab initio potential energy surface of Stark and Werner. Broad peaks which correspond to the direct scattering F+HD hindered-rotor states have been seen in the calculated spectra for both the FHD - and FDH - anions similar to previous FH2 - results. We have also found that the peak associated with the transition-state resonance in the FHD - spectrum but not in the FDH - spectrum. The present computational result predicts that the transition-state resonance can be observed even in low-energy resolution experiments

Takayanagi, Toshiyuki; Wada, Akira

2001-11-01

16

Acidity-dependent reactive uptake of isoprene photooxidation products  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

17

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

SciTech Connect

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

Wang, Si-Yi; Jiang, Xiang-Xu; Wei, Xin-Pan; Lee, Shuit-Tong, E-mail: apannale@suda.edu.cn, E-mail: yaohe@suda.edu.cn; He, Yao, E-mail: apannale@suda.edu.cn, E-mail: yaohe@suda.edu.cn [Institute of Functional Nano and Soft Materials - FUNSOM, Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, and Devices Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou, Jiangsu 215123 (China); Xu, Ting-Ting [Institute of Functional Nano and Soft Materials - FUNSOM, Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, and Devices Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou, Jiangsu 215123 (China); Center of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, Hong Kong, China and Department of Physics and Materials Science, City University of Hong Kong, Hong Kong (China)

2014-06-16

18

Reaction of acetaldehyde cations with water: The effects of CH3CHO vibrational mode and impact parameter on reactivity and product branching  

E-print Network

geometry, and reactant vibra- tional state, the interaction may result in direct, impulsive scattering instrument. The effects of reactant vibrational state and collision energy on reactivity, product branching parameters. PT also shows strongly mode-specific dependence on CH3CHO vibrational state. © 2001 American

Anderson, Scott L.

19

Reactive Molecular Dynamics Study of TATB Detonation Products  

NASA Astrophysics Data System (ADS)

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

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

2009-06-01

20

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

PubMed

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+H2), a heavy-light-light reaction (F+H2), 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. PMID:25028010

Warehime, Mick; Alexander, Millard H

2014-07-14

21

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

NASA Astrophysics Data System (ADS)

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+H2), a heavy-light-light reaction (F+H2), 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.

Warehime, Mick; Alexander, Millard H.

2014-07-01

22

Towards a specific reaction parameter density functional for reactive scattering of H2 from Pd(111)  

NASA Astrophysics Data System (ADS)

Recently, an implementation of the specific reaction parameter (SRP) approach to density functional theory (DFT) was used to study several reactive scattering experiments of H2 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 H2 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 H2-metal systems. In the calculations, the Born-Oppenheimer static surface approximations are used. A comparison to molecular beam sticking experiments, performed at incidence energies ?125 meV, on H2 + 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 H2 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 H2 + 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 H2 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 H2 + Pd(111), to facilitate the development of a more accurate theoretical description of this system.

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

2013-12-01

23

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

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

24

In situ reactive oxygen species production for tertiary wastewater treatment.  

PubMed

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

Guitaya, Léa; Drogui, Patrick; Blais, Jean François

2014-12-01

25

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

DOEpatents

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.

Herrmann, Steven Douglas

2014-05-27

26

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

Microsoft Academic Search

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

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

1997-01-01

27

Increased hydrogen peroxide and thiobarbituric acid-reactive products in expired breath condensate of asthmatic patients  

Microsoft Academic Search

Increased hydrogen peroxide and thiobarbituric acid-reactive products in expired breath condensate of asthmatic patients. A. Antczak, D. Nowak, B. Shariati, M. Król, G. Piasecka, Z. Kurmanowska. ©ERS Journals Ltd 1997. ABSTRACT: Symptoms of bronchial asthma are a manifestation of airway in- flammation. Circulatory leucocytes (predominantly eosinophils, mast cells and neu- trophils), release inflammatory mediators, including reactive oxygen species, i.e. superoxide

A. Antczak; D. Nowak; B. Shariati; M. Król; G. Piasecka; Z. Kurmanowska

1997-01-01

28

Reactive oxygen species production by catechol stabilized copper nanoparticles  

NASA Astrophysics Data System (ADS)

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

Chen, Cheng; Ahmed, Ishtiaq; Fruk, Ljiljana

2013-11-01

29

Deeply Virtual Compton Scattering and Exclusive Meson Production  

NASA Astrophysics Data System (ADS)

A selection of hard exclusive measurements (deeply virtual Compton Scattering and meson production) from past, present and future experimental programs are reviewed. The goal is the determination of the Generalized Parton Distributions which offer one of the most complete description of the partonic structure of the nucleon.

d'Hose, Nicole

2015-01-01

30

D ? production in deep inelastic scattering at HERA  

Microsoft Academic Search

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 <

S. Bhadra; W. R. Frisken; M. Khakzad; W. B. Schmidke; D. Mikunas; B. Musgrave; J. Repond; R. Stanek; R. L. Talaga; R. Yoshida; H. Zhang; M. C. K. Mattingly; F. Anselmo; P. Antonioli; G. Bari; M. Basile; L. Bellagamba; D. Boscherini; A. Bruni; G. Bruni; G. Cara Romeo; G. Castellini; L. Cifarelli; F. Cindolo; A. Contin; M. Corradi; S. de Pasquale; I. Gialas; P. Giusti; G. Iacobucci; G. Laurenti; G. Levi; A. Margotti; T. Massam; R. Nania; F. Palmonari; A. Pesci; A. Polini; G. Sartorelli; Y. Zamora Garcia; A. Zichichi; C. Amelung; A. Bornheim; I. Brock; K. Coböken; J. Crittenden; R. Deffner; M. Eckert; L. Feld; M. Grothe; H. Hartmann; K. Heinloth; L. Heinz; E. Hilger; H.-P. Jakob; U. F. Katz; E. Paul; M. Pfeiffer; Ch. Rembser; J. Stamm; R. Wedemeyer; D. S. Bailey; S. Campbell-Robson; W. N. Cottingham; B. Foster; R. Hall-Wilton; M. E. Hayes; G. P. Heath; H. F. Heath; D. Piccioni; D. G. Roff; R. J. Tapper; M. Arneodo; R. Ayad; M. Capua; A. Garfagnini; L. Iannotti; M. Schioppa; G. Susinno; J. Y. Kim; J. H. Lee; I. T. Lim; M. Y. Pac; A. Caldwell; N. Cartiglia; Z. Jing; W. Liu; J. A. Parsons; S. Ritz; S. Sampson; F. Sciulli; P. B. Straub; Q. Zhu; P. Borzemski; J. Chwastowski; A. Eskreys; Z. Jakubowski; M. B. Przybycien; M. Zachara; L. Zawiejski; L. Adamczyk; B. Bednarek; K. Jelen; D. Kisielewska; T. Kowalski; E. Rulikowska-Zarebska; L. Suszycki; J. Zajac; Z. Dulinski; A. Kotanski; G. Abbiendi; L. A. T. Bauerdick; U. Behrens; H. Beier; J. K. Bienlein; G. Cases; O. Deppe; K. Desler; G. Drews; U. Fricke; D. J. Gilkinson; C. Glasman; P. Göttlicher; J. Große-Knetter; T. Haas; W. Hain; D. Hasell; K. F. Johnson; M. Kasemann; W. Koch; U. Kötz; H. Kowalski; J. Labs; L. Lindemann; B. Löhr; M. Löwe; O. Manczak; J. Milewski; T. Monteiro; J. S. T. Ng; D. Notz; K. Ohrenberg; I. H. Park; A. Pellegrino; F. Pelucchi; K. Piotrzkowski; M. Roco; M. Rohde; J. Roldán; J. J. Ryan; A. A. Savin; U. Schneekloth; F. Selonke; B. Surrow; E. Tassi; T. Voß; D. Westphal; G. Wolf; U. Wollmer; C. Youngman; A. F. Zarnecki; W. Zeuner; B. D. Burow; H. J. Grabosch; A. Meyer; S. Schlenstedt; G. Barbagli; E. Gallo; P. Pelfer; G. Maccarrone; L. Votano; A. Bamberger; S. Eisenhardt; P. Markun; T. Trefzger; S. Wölfle; J. T. Bromley; N. H. Brook; P. J. Bussey; A. T. Doyle; D. H. Saxon; L. E. Sinclair; E. Strickland; M. L. Utley; R. Waugh; A. S. Wilson; I. Bohnet; N. Gendner; U. Holm; A. Meyer-Larsen; H. Salehi; K. Wick; L. K. Gladilin; D. Horstmann; D. Kçira; R. Klanner; E. Lohrmann; G. Poelz; W. Schott; F. Zetsche; T. C. Bacon; I. Butterworth; J. E. Cole; V. L. Harris; G. Howell; B. H. Y. Hung; L. Lamberti; K. R. Long; D. B. Miller; N. Pavel; A. Prinias; J. K. Sedgbeer; D. Sideris; A. F. Whitfield; U. Mallik; S. M. Wang; J. T. Wu; P. Cloth; D. Filges; J. I. Fleck; T. Ishii; M. Kuze; M. Nakao; K. Tokushuku; S. Yamada; Y. Yamazaki; S. H. An; S. B. Lee; S. W. Nam; H. S. Park; S. K. Park; F. Barreiro; J. P. Fernández; G. García; R. Graciani; J. M. Hernández; L. Hervás; L. Labarga; M. Martínez; J. del Peso; J. Puga; J. Terrón; J. F. de Trocóniz; F. Corriveau; D. S. Hanna; J. Hartmann; L. W. Hung; J. N. Lim; W. N. Murray; A. Ochs; M. Riveline; D. G. Stairs; M. St-Laurent; R. Ullmann; T. Tsurugai; V. Bashkirov; B. A. Dolgoshein; A. Stifutkin; G. L. Bashindzhagyan; P. F. Ermolov; Yu. A. Golubkov; L. A. Khein; N. A. Korotkova; I. A. Korzhavina; V. A. Kuzmin; O. Yu. Lukina; A. S. Proskuryakov; L. M. Shcheglova; A. V. Shumilin; A. N. Solomin; S. A. Zotkin; C. Bokel; M. Botje; N. Brümmer; F. Chlebana; J. Engelen; P. Kooijman; A. Kruse; A. van Sighem; H. Tiecke; W. Verkerke; J. Vossebeld; M. Vreeswijk; L. Wiggers; E. de Wolf; D. Acosta; B. Bylsma; L. S. Durkin; J. Gilmore; C. M. Ginsburg; C. L. Kim; T. Y. Ling; P. Nylander; T. A. Romanowski; H. E. Blaikley; R. J. Cashmore; A. M. Cooper-Sarkar; R. C. E. Devenish; J. K. Edmonds; N. Harnew; M. Lancaster; J. D. McFall; C. Nath; V. A. Noyes; A. Quadt; O. Ruske; J. R. Tickner; H. Uijterwaal; R. Walczak; D. S. Waters; A. Bertolin; R. Brugnera; R. Carlin; F. dal Corso; U. Dosselli; S. Limentani; M. Morandin; M. Posocco; L. Stanco; R. Stroili; C. Voci; J. Bulmahn; R. G. Feild; B. Y. Oh; J. R. Okrasinski; J. J. Whitmore; Y. Iga; G. D'Agostini; G. Marini; A. Nigro; M. Raso; J. C. Hart; N. A. McCubbin; T. P. Shah; E. Barberis; T. Dubbs; C. Heusch; M. van Hook; W. Lockman; J. T. Rahn; H. F.-W. Sadrozinski; A. Seiden; D. C. Williams; O. Schwarzer; A. H. Walenta; H. Abramowicz; G. Briskin; S. Dagan; T. Doeker; S. Kananov; A. Levy; T. Abe; T. Fusayasu; M. Inuzuka; K. Nagano; I. Suzuki; K. Umemori; T. Yamashita; R. Hamatsu; T. Hirose; K. Homma; S. Kitamura; T. Matsushita; K. Yamauchi; R. Cirio; M. Costa; M. I. Ferrero; S. Maselli; V. Monaco; C. Peroni; M. C. Petrucci; R. Sacchi; A. Solano; A. Staiano; M. Dardo; D. C. Bailey; M. Brkic; C.-P. Fagerstroem; G. F. Hartner; K. K. Joo

1997-01-01

31

Dijet production in diffractive deep inelastic scattering at HERA  

E-print Network

The production of dijets in diffractive deep inelastic scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of $61 \\pbi$. The dijet cross section has been measured for virtualities of the exchanged virtual photon, $5 4 \\gev$ and the jet with the highest transverse energy was required to have $E^*_{T,\\rm jet} > 5 \\gev$. All jets were required to be in the pseudorapidity range $-3.5 < \\eta^*_{\\rm jet} < 0$. The differential cross sections are compared to leading-order predictions and next-to-leading-order QCD calculations based on recent diffractive parton densities extracted from inclusive diffractive deep inelastic scattering data.

Chekanov, S; Magill, S; Musgrave, B; Nicholass, D; Repond, J; Yoshida, R; Mattingly, M C K; Jechow, M; Pavel, N; Yagues-Molina, A G; Antonelli, S; Antonioli, P; Bari, G; Basile, M; Bellagamba, L; Bindi, M; Boscherini, D; Bruni, A; Bruni, G; Cifarelli, L; Cindolo, F; Contin, A; Corradi, M; De Pasquale, S; Iacobucci, G; Margotti, A; Nania, R; Polini, A; Sartorelli, G; Zichichi, A; Bartsch, D; Brock, I; Hartmann, H; Hilger, E; Jakob, H P; Jüngst, M; Kind, O M; Nuncio-Quiroz, A E; Paul, E; Renner, R; Samson, U; Schonberg, V; Shehzadi, R; Wlasenko, M; Brook, N H; Heath, G P; Morris, J D; Capua, M; Fazio, S; Mastroberardino, A; Schioppa, M; Susinno, G; Tassi, E; Kim, J Y; Ma, K J; Ibrahim, Z A; Kamaluddin, B; Wan-Abdullah, W A T; Ning, Y; Ren, Z; Sciulli, F; Chwastowski, J; Eskreys, A; Figiel, J; Galas, A; Gil, M; Olkiewicz, K; Stopa, P; Zawiejski, L; Adamczyk, L; Bold, T; Grabowska-Bold, I; Kisielewska, D; Lukasik, J; Przybycien, M; Suszycki, L; Kotanski, A; Slominski, W; Adler, V; Behrens, U; Bloch, I; Blohm, C; Bonato, A; Borras, K; Ciesielski, R; Coppola, N; Dossanov, A; Drugakov, V; Fourletova, J; Geiser, A; Gladkov, D; Göttlicher, P; Grebenyuk, J; Gregor, I; Haas, T; Hain, W; Horn, C; Huttmann, A; Kahle, B; Katkov, I I; Klein, U; Kötz, U; Kowalski, H; Lobodzinska, E; Löhr, B; Mankel, R; Melzer-, I A; Pellmann; Miglioranzi, S; Montanari, A; Namsoo, T; Notz, D; Rinaldi, L; Roloff, P; Rubinsky, I; Santamarta, R; Schneekloth, U; Spiridonov, A; Stadie, H; Szuba, D; Szuba, J; Theedt, T; Wolf, G; Wrona, K; Youngman, C; Zeuner, W; Lohmann, W; Schlenstedt, S; Barbagli, G; Gallo, E; Pelfer, P G; Bamberger, A; Dobur, D; Karstens, F; Vlasov, N N; Bussey, P J; Doyle, A T; Dunne, W; Forrest, M; Saxon, D H; Skillicorn, I O; Gialas, I; Papageorgiu, K; Gosau, T; Holm, U; Klanner, R; Lohrmann, E; Salehi, H; Schleper, P; Schörner-Sadenius, T; Sztuk, J; Wichmann, K; Wick, K; Foudas, C; Fry, C; Long, K R; Tapper, A D; Kataoka, M; Matsumoto, T; Nagano, K; Tokushuku, K; Yamada, S; Yamazaki, Y; Barakbaev, A N; Boos, E G; Pokrovskiy, N S; Zhautykov, B O; Aushev, V; Borodin, M; Kozulia, A; Lisovyi, M; Son, D; De Favereau, J; Piotrzkowski, K; Barreiro, F; Glasman, C; Jiménez, M; Labarga, L; Del Peso, J; Ron, E; Soares, M; Terron, J; Zambrana, M; Corriveau, F; Liu, C; Walsh, R; Zhou, C; Tsurugai, T; Antonov, A; Dolgoshein, B A; Sosnovtsev, V; Stifutkin, A; Suchkov, S; Dementiev, R K; Ermolov, P F; Gladilin, L K; Khein, L A; Korzhavina, I A; Kuzmin, V A; Levchenko, B B; Lukina, O Yu; Proskuryakov, A S; Shcheglova, L M; Zotkin, D S; Zotkin, S A; Abt, I; Büttner, C; Caldwell, A; Kollar, D; Schmidke, W B; Sutiak, J; Grigorescu, G; Keramidas, A; Koffeman, E; Kooijman, P; Pellegrino, A; Tiecke, H; Vázquez, M; Wiggers, L; Brümmer, N; Bylsma, B; Durkin, L S; Lee, A; Ling, T Y; Allfrey, P D; Bell, M A; Cooper-Sarkar, A M; Devenish, R C E; Ferrando, J; Foster, B; Korcsak-Gorzo, K; Oliver, K; Patel, S; Roberfroid, V; Robertson, A; Straub, P B; Uribe-Estrada, C; Walczak, R; Bellan, P; Bertolin, A; Brugnera, R; Carlin, R; Dal Corso, F; Dusini, S; Garfagnini, A; Limentani, S; Longhin, A; Stanco, L; Turcato, M; Oh, B Y; Raval, A; Ukleja, J; Whitmore, J J; Iga, Y; D'Agostini, G; Marini, G; Nigro, A; Cole, J E; Hart, J C; Abramowicz, H; Gabareen, A; Ingbir, R; Kananov, S; Levy, A; Smith, O; Stern, A; Kuze, M; Maeda, J; Hori, R; Kagawa, S; Okazaki, N; Shimizu, S; Tawara, T; Hamatsu, R; Kaji, H; Kitamura, S; Ota, O; Ri, Y D; Ferrero, M I; Monaco, V; Sacchi, R; Solano, A; Arneodo, M; Ruspa, M; Fourletov, S; Martin, J F; Boutle, S K; Butterworth, J M; Gwenlan, C; Jones, T W; Loizides, J H; Sutton, M R; Wing, M; Brzozowska, B; Ciborowski, J; Grzelak, G; Kulinski, P; Luzniak, P; Malka, J; Nowak, R J; Pawlak, J M; Tymieniecka, T; Ukleja, A; Zarnecki, A F; Adamus, M; Plucinsky, P P; Eisenberg, Y; Giller, I; Hochman, D; Karshon, U; Rosin, M; Brownson, E; Danielson, T; Everett, A; Kcira, D; Reeder, D D; Ryan, P; Savin, A A; Smith, W H; Wolfe, H; Bhadra, S; Catterall, C D; Cui, Y; Hartner, G; Menary, S; Noor, U; Standage, J; Whyte, J

2007-01-01

32

Neutral strange particle production in deep inelastic scattering at HERA  

Microsoft Academic Search

This paper presents measurements ofK0 and ? production in neutral current, deep inelastic scattering of 26.7 GeV electrons and 820 GeV protons in the kinematic range 10Q22, 0.0003xy>0.04. Average multiplicities forK0 and ? production are determined for transverse momentapT>0.5 GeV and pseudorapidities |?|e+e- experiments. The production properties ofK0' s in events with and without a large rapidity gap with respect

M. Derick; D. Krakauer; S. Magill; D. Mikunas; B. Musgrave; J. Repond; R. Stanek; R. L. Talaga; H. Zhang; R. Ayad; G. Bari; M. Basile; L. Bellagamba; D. Boscherini; A. Bruni; G. Bruni; P. Bruni; G. Cara Romeo; G. Castellini; M. Chiarini; L. Cifarelli; F. Cindolo; A. Contin; M. Corradi; I. Gialas; P. Giusti; G. Iacobucci; G. Laurenti; G. Levi; A. Margotti; T. Massam; R. Nania; C. Nemoz; F. Palmonari; A. Polini; G. Sartorelli; R. Timellini; Y. Zamora Garcia; A. Zichichi; A. Bargende; J. Crittenden; K. Desch; B. Diekmann; T. Doeker; M. Eckert; L. Feld; A. Frey; M. Geerts; G. Geitz; M. Grothe; T. Haas; H. Hartmann; K. Heinloth; E. Hilger; H.-P. Jakob; U. F. Katz; S. M. Mari; A. Mass; S. Mengel; J. Mollen; E. Paul; Ch. Rembser; D. Schramm; J. Stamm; R. Wedemeyer; S. Campbell-Robson; A. Cassidy; N. Dyce; B. Foster; S. George; R. Gilmore; G. P. Heath; H. F. Heath; T. J. Llewellyn; C. J. S. Morgado; D. J. P. Norman; J. A. O'Mara; R. J. Tapper; S. S. Wilson; R. Yoshida; R. R. Rau; M. Arneodo; L. Iannotti; M. Schioppa; G. Susinno; A. Bernstein; A. Caldwell; N. Cartiglia; J. A. Parsons; S. Ritz; F. Sciulli; P. B. Straub; L. Wai; S. Yang; Q. Zhu; P. Borzemski; J. Chwastowski; A. Eskreys; K. Piotrzkowski; M. Zachara; L. Zawiejski; L. Adamezyk; B. Bednarek; K. Jelen; D. Kisielewska; T. Kowalski; E. Rulikowska-Zarebska; L. Suszycki; J. Zajac; A. Kotanski; M. Przybycien; L. A. T. Bauerdick; U. Behrens; H. Beier; J. K. Bienlein; C. Coldewey; O. Deppe; K. Desler; G. Drews; M. Flasinski; D. J. Gilkinson; C. Glasman; P. Göttlicher; J. Große-Knetter; B. Gutjahr; W. Hain; D. Hasell; H. Heßling; Y. Iga; P. Joos; M. Kasemann; R. Klanner; W. Koch; L. Köpke; U. Kötz; H. Kowalski; J. Labs; A. Ladage; B. Löhr; M. Löwe; D. Lüke; J. Mainusch; O. Manczak; T. Monteiro; J. S. T. Ng; S. Nickel; D. Notz; K. Ohrenberg; M. Roco; M. Rohde; J. Roldán; U. Schneekloth; W. Schulz; F. Selonke; E. Stiliaris; B. Surrow; T. Voß; D. Westphal; G. Wolf; C. Youngman; J. F. Zhou; H. J. Grabosch; A. Kharchilava; A. Leich; M. C. K. Mattingly; A. Meyer; S. Schlenstedt; N. Wulff; G. Barbagli; P. Pelfer; G. Anzivino; G. Maccarrone; S. De Pasquale; L. Votano; A. Bamberger; S. Eisenhardt; A. Freidhof; S. Söldner-Rembold; J. Schroeder; T. Trefzger; N. H. Brook; P. J. Bussey; A. T. Doyle; J. I. Fleck; D. H. Saxon; M. L. Utley; A. S. Wilson; A. Dannemann; U. Holm; D. Horstmann; T. Neumann; R. Sinkus; K. Wick; E. Badura; B. D. Burow; L. Hagge; E. Lohrmann; J. Milewski; M. Nakahata; N. Pavel; G. Poelz; W. Schott; F. Zetsche; T. C. Bacon; I. Butterworth; E. Gallo; V. L. Harris; B. Y. H. Hung; K. R. Long; D. B. Miller; P. P. O. Morawitz; A. Prinias; J. K. Sedgbeer; A. F. Whitfield; U. Mallik; E. McCliment; M. Z. Wang; S. M. Wang; J. T. Wu; Y. Zhang; P. Cloth; D. Filges; S. H. An; S. M. Hong; S. W. Nam; S. K. Park; M. H. Suh; S. H. Yon; R. Imlay; S. Kartik; H.-J. Kim; R. R. McNeil; W. Metcalf; V. K. Nadendla; F. Barreiro; G. Cases; J. P. Fernandez; R. Graciani; J. M. Hernández; L. Hervás; L. Labarga; M. Martinez; J. del Peso; J. Puga; J. Terron; J. F. de Trocóniz; G. R. Smith; F. Corriveau; D. S. Hanna; J. Hartmann; L. W. Hung; J. N. Lim; C. G. Matthews; P. M. Patel; L. E. Sinclair; D. G. Stairs; M. St. Laurent; R. Ullmann; G. Zacek; V. Bashkirov; B. A. Dolgoshein; A. Stifutkin; G. L. Bashindzhagyan; P. F. Ermolov; L. K. Gladilin; Y. A. Golubkov; V. D. Kobrin; V. A. Kuzmin; A. S. Proskuryakov; A. A. Savin; L. M. Shcheglova; A. N. Solomin; N. P. Zotov; M. Botje; F. Chlebana; A. Dake; J. Engelen; M. de Kamps; P. Kooijman; A. Kruse; H. Tiecke; W. Verkerke; M. Vreeswijk; L. Wiggers; E. de Wolf; R. van Woudenberg; D. Acosta; B. Bylsma; L. S. Durkin; K. Honscheid; C. Li; T. Y. Ling; K. W. McLean; W. N. Murray; I. H. Park; T. A. Romanowski; R. Seidlein; D. S. Bailey; A. Byrne; R. J. Cashmore; A. M. Cooper-Sarkar; R. C. E. Devenish; N. Harnew; M. Lancaster; L. Lindemann; J. D. McFall; C. Nath; V. A. Noyes; A. Quadt; J. R. Tickner; H. Uijterwaal; R. Walczak; D. S. Waters; F. F. Wilson; T. Yip; G. Abbrendi; A. Bertolin; R. Brugnera; R. Carlin; F. Dal Corso; M. De Giorgi; U. Dosselli; S. Limentani; M. Morandin; M. Posocco; L. Stanco; R. Stroili; C. Voci; J. Bulmahn; J. M. Butterworth; R. G. Feild; B. Y. Oh; J. J. Whitmore; G. D'Agostini; G. Marini; A. Nigro; E. Tassi; J. C. Hart; N. A. McCubbin; K. Prytz; T. P. Shah; T. L. Short; E. Barberis; T. Dubbs; C. Heusch; M. Van Hook; B. Hubbard; W. Lockman; J. T. Rahn; H. F.-W. Sadrozinski; A. Seiden; J. Biltzinger; R. J. Seifert; O. Schwarzer; A. H. Walenta; G. Zech; H. Abramowicz; G. Briskin; S. Dagan; A. Levy; T. Hasegawa; M. Hazumi; T. Ishii; M. Kuze; S. Mine; Y. Nagasawa; M. Nakao; I. Suzuki; K. Tokushuku; S. Yamada; Y. Yamazaki; M. Chiba; R. Hamatsu; T. Hirose; K. Homma; S. Kitamura; Y. Nakamitsu; K. Yamauchi; R. Cirio; M. Costa; M. I. Ferrero; L. Lamberti; S. Maselli; C. Peroni

1995-01-01

33

Reactive Molecular Dynamics Study of TATB Detonation Products  

Microsoft Academic Search

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

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

2009-01-01

34

Dijet production in diffractive deep inelastic scattering at HERA  

Microsoft Academic Search

The production of dijets in diffractive deep inelastic scattering has been measured with the ZEUS detector at HERA using an\\u000a integrated luminosity of 61 pb-1. The dijet cross section has been measured for virtualities of the exchanged virtual photon, 5 2 2, and ?*p centre-of-mass energies, 100 T algorithm in the ?*p frame, were required to have a transverse energy E*

S. Chekanov; M. Derrick; S. Magill; B. Musgrave; D. Nicholass; J. Repond; R. Yoshida; M. C. K. Mattingly; M. Jechow; N. Pavel; A. G. Yagües Molina; S. Antonelli; P. Antonioli; G. Bari; M. Basile; L. Bellagamba; M. Bindi; D. Boscherini; A. Bruni; G. Bruni; L. Cifarelli; F. Cindolo; A. Contin; M. Corradi; S. De Pasquale; G. Iacobucci; A. Margotti; R. Nania; A. Polini; G. Sartorelli; A. Zichichi; D. Bartsch; I. Brock; H. Hartmann; E. Hilger; H.-P. Jakob; M. Jüngst; O. M. Kind; A. E. Nuncio-Quiroz; E. Paul; R. Renner; U. Samson; V. Schönberg; R. Shehzadi; M. Wlasenko; N. H. Brook; G. P. Heath; J. D. Morris; M. Capua; S. Fazio; A. Mastroberardino; M. Schioppa; G. Susinno; E. Tassi; J. Y. Kim; K. J. Ma; Z. A. Ibrahim; B. Kamaluddin; W. A. T. Wan Abdullah; Y. Ning; Z. Ren; F. Sciulli; J. Chwastowski; A. Eskreys; J. Figiel; A. Galas; M. Gil; K. Olkiewicz; P. Stopa; L. Zawiejski; L. Adamczyk; T. Bold; I. Grabowska-Bo?d; D. Kisielewska; J. ?ukasik; M. Przybycien; L. Suszycki; A. Kotanski; W. Slominski; V. Adler; U. Behrens; I. Bloch; C. Blohm; A. Bonato; K. Borras; R. Ciesielski; N. Coppola; A. Dossanov; V. Drugakov; J. Fourletova; A. Geiser; D. Gladkov; P. Göttlicher; J. Grebenyuk; I. Gregor; T. Haas; W. Hain; C. Horn; A. Hüttmann; B. Kahle; I. I. Katkov; U. Klein; U. Kötz; H. Kowalski; E. Lobodzinska; B. Löhr; R. Mankel; I.-A. Melzer-Pellmann; S. Miglioranzi; A. Montanari; T. Namsoo; D. Notz; L. Rinaldi; P. Roloff; I. Rubinsky; R. Santamarta; U. Schneekloth; A. Spiridonov; H. Stadie; D. Szuba; J. Szuba; T. Theedt; G. Wolf; K. Wrona; C. Youngman; W. Zeuner; W. Lohmann; S. Schlenstedt; G. Barbagli; E. Gallo; P. G. Pelfer; A. Bamberger; D. Dobur; F. Karstens; N. N. Vlasov; P. J. Bussey; A. T. Doyle; W. Dunne; M. Forrest; D. H. Saxon; I. O. Skillicorn; I. Gialas; K. Papageorgiu; T. Gosau; U. Holm; R. Klanner; E. Lohrmann; H. Salehi; P. Schleper; T. Schörner-Sadenius; J. Sztuk; K. Wichmann; K. Wick; C. Foudas; C. Fry; K. R. Long; A. D. Tapper; M. Kataoka; T. Matsumoto; K. Nagano; K. Tokushuku; S. Yamada; Y. Yamazaki; A. N. Barakbaev; E. G. Boos; N. S. Pokrovskiy; B. O. Zhautykov; V. Aushev; M. Borodin; A. Kozulia; M. Lisovyi; D. Son; J. de Favereau; K. Piotrzkowski; F. Barreiro; C. Glasman; M. Jimenez; L. Labarga; J. del Peso; E. Ron; M. Soares; J. Terrón; M. Zambrana; F. Corriveau; C. Liu; R. Walsh; C. Zhou; T. Tsurugai; A. Antonov; B. A. Dolgoshein; V. Sosnovtsev; A. Stifutkin; S. Suchkov; R. K. Dementiev; P. F. Ermolov; L. K. Gladilin; L. A. Khein; I. A. Korzhavina; V. A. Kuzmin; B. B. Levchenko; O. Y. Lukina; A. S. Proskuryakov; L. M. Shcheglova; D. S. Zotkin; S. A. Zotkin; I. Abt; C. Büttner; A. Caldwell; D. Kollar; W. B. Schmidke; J. Sutiak; G. Grigorescu; A. Keramidas; E. Koffeman; P. Kooijman; A. Pellegrino; H. Tiecke; M. Vázquez; L. Wiggers; N. Brümmer; B. Bylsma; L. S. Durkin; A. Lee; T. Y. Ling; P. D. Allfrey; M. A. Bell; A. M. Cooper-Sarkar; R. C. E. Devenish; J. Ferrando; B. Foster; K. Korcsak-Gorzo; K. Oliver; S. Patel; V. Roberfroid; A. Robertson; P. B. Straub; C. Uribe-Estrada; R. Walczak; P. Bellan; A. Bertolin; R. Brugnera; R. Carlin; F. Dal Corso; S. Dusini; A. Garfagnini; S. Limentani; A. Longhin; L. Stanco; M. Turcato; B. Y. Oh; A. Raval; J. Ukleja; J. J. Whitmore; Y. Iga; G. D’Agostini; G. Marini; A. Nigro; J. E. Cole; J. C. Hart; H. Abramowicz; A. Gabareen; R. Ingbir; S. Kananov; A. Levy; O. Smith; A. Stern; M. Kuze; J. Maeda; R. Hori; S. Kagawa; N. Okazaki; S. Shimizu; T. Tawara; R. Hamatsu; H. Kaji; S. Kitamura; O. Ota; Y. D. Ri; M. I. Ferrero; V. Monaco; R. Sacchi; A. Solano; M. Arneodo; M. Ruspa; S. Fourletov; J. F. Martin; S. K. Boutle; J. M. Butterworth; C. Gwenlan; T. W. Jones; J. H. Loizides; M. R. Sutton; M. Wing; B. Brzozowska; J. Ciborowski; G. Grzelak; P. Kulinski; P. ?u?niak; J. Malka; R. J. Nowak; J. M. Pawlak; T. Tymieniecka; A. Ukleja; A. F. ?arnecki; M. Adamus; P. Plucinski; Y. Eisenberg; I. Giller; D. Hochman; U. Karshon; M. Rosin; E. Brownson; T. Danielson; A. Everett; D. Kçira; D. D. Reeder; P. Ryan; A. A. Savin; W. H. Smith; H. Wolfe; S. Bhadra; C. D. Catterall; Y. Cui; G. Hartner; S. Menary; U. Noor; J. Standage; J. Whyte

2007-01-01

35

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

SciTech Connect

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

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

2012-07-01

36

Reactive Oxygen Production Induced by the Gut Microbiota: Pharmacotherapeutic Implications  

PubMed Central

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-?B 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

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

2014-01-01

37

Meson production in high-energy electron-nucleus scattering  

E-print Network

Pseudoscalar mesons can be produced and studied in high-energy electron-nucleus scattering. We review and extend our previous analysis of meson production in the nuclear Coulomb field. The $P\\rightarrow \\gamma \\gamma$ decay rates are most directly determined for mesons produced in the double-Coulomb region where both photons are nearly real, and provided the background-hadronic contribution remains small. The larger the mass of the meson the higher the electron energy needed to assure such a condition.

Göran Fäldt

2012-02-03

38

Measurement of beauty production in deep inelastic scattering at HERA  

Microsoft Academic Search

The beauty production cross section for deep inelastic scattering events with at least one hard jet in the Breit frame together with a muon has been measured, for photon virtualities Q2>2?GeV2, with the ZEUS detector at HERA using integrated luminosity of 72 pb?1. The total visible cross section is ?bb¯(ep?e?jet??X)=40.9±5.7(stat.)?4.4+6.0(syst.)?pb. The next-to-leading order QCD prediction lies about 2.5 standard deviations

S. Bhadra; C. D. Catterall; S. Fourletov; G. Hartner; S MIGLIORANZI; M. Soares; J. Standage; J. Repond; R. Yoshida; M. C. K. Mattingly; N. Pavel; P. Antonioli; G. Bari; M. Basile; L. Bellagamba; D. Boscherini; A. Bruni; G. Bruni; G. Cara Romeo; L. Cifarelli; F. Cindolo; A. Contin; M. Corradi; S. de Pasquale; P. Giusti; G. Iacobucci; A. Margotti; A. Montanari; R. Nania; F. Palmonari; A. Pesci; L. Rinaldi; G. Sartorelli; A. Zichichi; G. Aghuzumtsyan; D. Bartsch; I. Brock; S. Goers; H. Hartmann; E. Hilger; P. Irrgang; H.-P. Jakob; O. Kind; U. Meyer; E. Paul; J. Rautenberg; R. Renner; A. Stifutkin; J. Tandler; K. C. Voss; M. Wang; D. S. Bailey; N. H. Brook; J. E. Cole; G. P. Heath; T. Namsoo; S. Robins; M. Wing; M. Capua; A. Mastroberardino; M. Schioppa; G. Susinno; J. Y. Kim; I. T. Lim; K. J. Ma; M. Y. Pac; M. Helbich; Y. Ning; Z. Ren; W. B. Schmidke; F. Sciulli; J. Chwastowski; A. Eskreys; J. Figiel; A. Galas; K. Olkiewicz; P. Stopa; L. Zawiejski; L. Adamczyk; T. Bold; I. Grabowska-Bold; D. Kisielewska; A. M. Kowal; M. Kowal; J. Lukasik; M. Przybycien; L. Suszycki; D. Szuba; J. Szuba; A. Kotanski; W. Slominski; V. Adler; U. Behrens; I. Bloch; K. Borras; V. Chiochia; D. Dannheim; G. Drews; J. Fourletova; U. Fricke; A. Geiser; P. Göttlicher; O. Gutsche; T. Haas; W. Hain; S. Hillert; C. Horn; B. Kahle; U. Kötz; H. Kowalski; G. Kramberger; H. Labes; D. Lelas; H. Lim; B. Löhr; R. Mankel; I.-A. Melzer-Pellmann; C. N. Nguyen; D. Notz; A. E. Nuncio-Quiroz; A. Polini; A. Raval; U. Schneekloth; U. Stösslein; G. Wolf; C. Youngman; W. Zeuner; S. Schlenstedt; G. Barbagli; E. Gallo; C. Genta; P. G. Pelfer; A. Bamberger; A. Benen; F. Karstens; D. Dobur; N. N. Vlasov; P. J. Bussey; A. T. Doyle; J. Ferrando; S. Hanlon; D. H. Saxon; I. O. Skillicorn; I. Gialas; T. Carli; T. Gosau; U. Holm; N. Krumnack; E. Lohrmann; M. Milite; H. Salehi; P. Schleper; T. Schörner-Sadenius; S. Stonjek; K. Wichmann; K. Wick; A. Ziegler; C. Collins-Tooth; C. Foudas; R. Gonçalo; K. R. Long; A. D. Tapper; P. Cloth; D. Filges; M. Kataoka; K. Nagano; K. Tokushuku; S. Yamada; Y. Yamazaki; A. N. Barakbaev; E. G. Boos; N. S. Pokrovskiy; B. O. Zhautykov; D. Son; J. de Favereau; K. Piotrzkowski; F. Barreiro; C. Glasman; O. González; L. Labarga; J. del Peso; E. Tassi; J. Terrón; M. Zambrana; M. Barbi; F. Corriveau; S. Gliga; J. Lainesse; S. Padhi; D. G. Stairs; R. Walsh; T. Tsurugai; A. Antonov; P. Danilov; B. A. Dolgoshein; D. Gladkov; V. Sosnovtsev; S. Suchkov; R. K. Dementiev; P. F. Ermolov; I. I. Katkov; L. A. Khein; I. A. Korzhavina; V. A. Kuzmin; B. B. Levchenko; O. Yu. Lukina; A. S. Proskuryakov; L. M. Shcheglova; S. A. Zotkin; I. Abt; C. Büttner; A. Caldwell; X. Liu; J. Sutiak; N. Coppola; G. Grigorescu; S. Grijpink; A. Keramidas; E. Koffeman; P. Kooijman; E. Maddox; A. Pellegrino; S. Schagen; H. Tiecke; M. Vázquez; L. Wiggers; E. de Wolf; N. Brümmer; B. Bylsma; L. S. Durkin; T. Y. Ling; A. M. Cooper-Sarkar; A. Cottrell; R. C. E. Devenish; B. Foster; G. Grzelak; C. Gwenlan; T. Kohno; S. Patel; P. B. Straub; R. Walczak; P. Bellan; A. Bertolin; R. Brugnera; R. Carlin; F. dal Corso; S. Dusini; A. Garfagnini; S. Limentani; A. Longhin; A. Parenti; M. Posocco; L. Stanco; M. Turcato; E. A. Heaphy; F. Metlica; B. Y. Oh; J. J. Whitmore; Y. Iga; G. D'Agostini; G. Marini; A. Nigro; C. Cormack; J. C. Hart; N. A. McCubbin; C. Heusch; I. H. Park; H. Abramowicz; A. Gabareen; S. Kananov; A. Kreisel; A. Levy; M. Kuze; T. Fusayasu; S. Kagawa; T. Tawara; T. Yamashita; R. Hamatsu; T. Hirose; M. Inuzuka; H. Kaji; S. Kitamura; K. Matsuzawa; M. Costa; M. I. Ferrero; V. Monaco; R. Sacchi; A. Solano; M. Arneodo; M. Ruspa; T. Koop; J. F. Martin; A. Mirea; J. M. Butterworth; R. Hall-Wilton; T. W. Jones; M. S. Lightwood; M. R. Sutton; C. Targett-Adams; J. Ciborowski; R. Ciesielski; P. Luzniak; R. J. Nowak; J. M. Pawlak; J. Sztuk; T. Tymieniecka; A. Ukleja; J. Ukleja; A. F. Zarnecki; M. Adamus; P. Plucinski; Y. Eisenberg; D. Hochman; U. Karshon; M. Riveline; A. Everett; L. K. Gladilin; D. Kçira; S. Lammers; L. Li; D. D. Reeder; M. Rosin; P. Ryan; A. A. Savin; W. H. Smith; S. Dhawan; S. Menary

2004-01-01

39

Discharge-aided reactive laser ablation for ultrafine powder production  

NASA Astrophysics Data System (ADS)

Ultrafine alumina powder was produced by aluminum target ablation with a Nd:YAG laser beam (1064 nm wavelength; 340 mJ/pulse energy; 7 ns pulse duration; 10 pps repetition rate), in a 120 Torr O2 atmosphere. A theoretical approach for the ablation process, based on laser energy absorption and energy balance in the target, is used for comparison with the experimental production rate. Three experimental irradiation conditions were chosen: (1) energy density of 5 J/cm2, considered reference (RDE), (2) lower energy density of 2.5 J/cm2 (LDE) and (3) RDE with auxiliary discharge between an auxiliary electrode and target, triggered by the ablation plume (RDA). Calculated and experimental data of target weight loss show good agreement (135 ng/pulse, calculated, and 100, 110, 120 ng/pulse, experimentally, for RDE, LDE, RDA conditions, respectively). The X-Ray Diffraction spectra of alumina show formation of (gamma) -alumina particles only, especially in LDE and RDA conditions. From Scanning Electron Microscopy size analysis, a decrease of particle size, in LDE and RDA irradiating conditions, is observed. The decrease of laser beam fluence or aiding of ablation using an auxiliary discharge is both favorable for the production of high quality powder, without diminishing the production rate. This can be a good basis for future improvement of the ultrafine powder production process.

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

1998-07-01

40

Chemical Characterization and Reactivity of Fuel-Oxidizer Reaction Product  

NASA Technical Reports Server (NTRS)

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.

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

1997-01-01

41

Surface Reactivity, Cytotoxic, and Morphological Transforming Effects of Diatomaceous Earth Products in Syrian Hamster Embryo Cells  

Microsoft Academic Search

In order to evaluate the effect of thermal treatments on the sur- face 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 lab- oratory at 900? C (DE 900)

Z. Elias; Ivana Fenoglio; Mara Ghiazza; Marie-Celeste Daniere; Francine Terzetti; Christian Darne; Catherine Coulais; Ildiko Matekovits; Bice Fubini

2006-01-01

42

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

Microsoft Academic Search

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

Tzou Chi Huang; Ya Ting Lin; Kuo Pin Chuang

2010-01-01

43

Azimuthal angle dependence of dijet production in unpolarized hadron scattering  

SciTech Connect

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

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

2008-08-01

44

Optical mapping of myocardial reactive oxygen species production throughout the reperfusion of global ischemia  

NASA Astrophysics Data System (ADS)

Reactive oxygen species (ROS) are short-lived, highly reactive chemical entities that play significant roles in all levels of biology. However, their measurement requires destructive preparation, thereby limiting the continuous measurement of ROS in a living tissue. We develop an optical mapping system to visualize ROS production in an isolated and perfused rat heart. By staining the heart with dihydroethidium (DHE), a 532-nm laser beam is directed to the epicardial surface, where we collect the red fluorescence (>600 nm) for semiquantitative analysis. With this system, ROS production as well as ventricular pressure and ECG in isolated perfused rat hearts are monitored throughout the reperfusion of global ischemia. Ischemia would decrease myocardial ROS production, while reperfusion would immediately result in sustained ROS overproduction. Optical mapping would provide information regarding the spatial distribution and temporal evolution of myocardial ROS production, which would enhance knowledge of the role of free radicals in cardiovascular biology.

Lu, Long-sheng; Liu, Yen-Bin; Sun, Chia-Wei; Lin, Lung-Chun; Su, Ming-jia; Wu, Chau-Chung

2006-03-01

45

Raman scattering studies of reactive ion-etched MBE 100-line n-type GaAs  

NASA Astrophysics Data System (ADS)

Raman scattering is used to characterize the effects of reactive ion etching (RIE) on the surface properties of single-crystal MBE-grown 100-line n-type GaAs. The longitudinal optic (LO) phonon and the coupled plasmon LO-phonon modes observed in the Raman spectra were studied for highly Si-doped samples with free carrier concentrations of (5-9) x 10 to the 18th/cu cm to probe the surface quality. Symmetry-forbidden transverse optic phonon Raman spectra provided information about the surface quality of lightly Si-doped samples with free carrier concentrations of 3 x 10 to the 17th/cu cm. Electrical measurements on Schottky diodes formed on lightly doped RIE samples support the Raman results. The effect of rapid thermal annealing was also studied. Samples etched at ion energies of 400 eV showed surface disorder confined to within 10 + or - 2 nm from the surface. A low-pressure multipolar reactive ion etch system at ion bombardment energies below 200 eV allows etching without introducing measurable surface disordering.

Roughani, Bahram; Jackson, Howard E.; Jbara, Joubran J.; Mantei, Thomas D.; Hickman, G.

1989-05-01

46

Reactive scattering of a supersonic alkali atom beam: K+Br2 BrCN, SnCl4, PCl3, CCl4, CH3I  

Microsoft Academic Search

Angular distribution measurements of reactive scattering of a supersonic potassium atom beam by a series of molecules are reported with initial kinetic energy (˜ 5 kcal mole-1) above the thermal energy range. The narrow Laval nozzle velocity distribution gives improved resolution over thermal energy measurements. Total reaction cross sections are found to decrease with energy. Differential reaction cross sections for

J. C. Whitehead; D. R. Hardin; R. Grice

1972-01-01

47

EC-SPE-stripline-NMR analysis of reactive products: a feasibility study.  

PubMed

Flow-through electrochemical conversion (EC) of drug-like molecules was hyphenated to miniaturized nuclear magnetic resonance spectroscopy (NMR) via on-line solid-phase extraction (SPE). After EC of the prominent p38? mitogen-activated protein kinase inhibitor BIRB796 into its reactive products, the SPE step provided preconcentration of the EC products and solvent exchange for NMR analysis. The acquisition of NMR spectra of the mass-limited samples was achieved in a stripline probe with a detection volume of 150 nL offering superior mass sensitivity. This hyphenated EC-SPE-stripline-NMR setup enabled the detection of the reactive products using only minute amounts of substrate. Furthermore, the integration of conversion and detection into one flow setup counteracts incorrect assessments caused by the degradation of reactive products. However, apparent interferences of the NMR magnetic field with the EC, leading to a low product yield, so far demanded relatively long signal averaging. A critical assessment of what is and what is not (yet) possible with this approach is presented, for example in terms of structure elucidation and the estimation of concentrations. Additionally, promising routes for further improvement of EC-SPE-stripline-NMR are discussed. PMID:23812883

Falck, David; Oosthoek-de Vries, Anna J; Kolkman, Ard; Lingeman, Henk; Honing, Maarten; Wijmenga, Sybren S; Kentgens, Arno P M; Niessen, Wilfried M A

2013-08-01

48

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

SciTech Connect

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.

Yu, Shengrui; Su, Shu; Dai, Dongxu; Yuan, Kaijun, E-mail: kjyuan@dicp.ac.cn, E-mail: xmyang@dicp.ac.cn; Yang, Xueming, E-mail: kjyuan@dicp.ac.cn, E-mail: xmyang@dicp.ac.cn [State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023 (China)] [State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023 (China)

2014-01-21

49

Induced reactive oxygen species improve enzyme production from Aspergillus niger cultivation.  

PubMed

Intracellular reactive oxygen species (iROS) induction by HOCl was used as a novel strategy to improve enzyme productivities in Aspergillus niger growing in a bioreactor. With induced iROS, the specific intracellular activities of alpha-amylase, protease, catalase, and glucose oxidase were increased by about 170%, 250%, 320%, and 260%, respectively. The optimum specific iROS level for achieving maximum cell concentration and enzyme production was about 15 mmol g cell-1. The type of iROS inducing the enzyme production was identified to be a derivative of the superoxide radical. PMID:12882014

Sahoo, Susmita; Rao, K Krishnamurthy; Suraishkumar, G K

2003-05-01

50

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

PubMed

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

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

2014-10-20

51

Induced reactive oxygen species improve enzyme production from Aspergillus niger cultivation  

Microsoft Academic Search

Intracellular reactive oxygen species (iROS) induction by HOCl was used as a novel strategy to improve enzyme productivities in Aspergillus niger growing in a bioreactor. With induced iROS, the specific intracellular activities of a-amylase, protease, catalase, and glucose oxidase were increased by about 170%, 250%, 320%, and 260%, respectively. The optimum specific iROS level for achieving maximum cell concentration and

Susmita Sahoo; K. Krishnamurthy Rao; G. K. Suraishkumar

2003-01-01

52

Water reactivity with tungsten oxides: H2 production and kinetic traps  

Microsoft Academic Search

In a recent mass spectrometry\\/photoelectron spectroscopy study on the reactions between W2Oy- (y=2-6) and water, Jarrold and co-workers [J. Chem. Phys. 130, 124314 (2009)] observed interesting differences in the reactivity of the different cluster ions. Particularly noteworthy is the observation that the only product with the incorporation of hydrogens is a single peak corresponding to W2O6H2-. As reactions between metal

Nicholas J. Mayhall; David W. Rothgeb; Ekram Hossain; Caroline Chick Jarrold; Krishnan Raghavachari

2009-01-01

53

Products of rectangular random matrices: Singular values and progressive scattering  

NASA Astrophysics Data System (ADS)

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.

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

2013-11-01

54

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

PubMed

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

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

2013-11-01

55

A rigorous treatment of reactive scattering on a single adiabatic potential energy surface  

Microsoft Academic Search

A rigorous adiabatic kinetic energy operator has been derived for general adiabatic bimolecular chemical reactions. Three regions, i.e. the reactant, coupling and product regions, are classified in the configuration space by the character of the potential energy surfaces. It is shown that the present adiabatic kinetic energy operator is different from the commonly adopted form only in the coupling region.

Lichang Wang

1998-01-01

56

Catalytic reactive separation system for energy-efficient production of cumene  

DOEpatents

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

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

2009-07-28

57

Computational simulation of reactive species production by methane-air DBD at high pressure and high temperature  

NASA Astrophysics Data System (ADS)

Computational simulations of a single streamer in DBD in lean methane-air mixture at pressure of 1 and 3 atm and temperature of 300 and 500 K were conducted for plasma-enhanced chemical reactions in a closed system. The effects of surrounding pressure and temperature are characterized for reactive species production by a DBD discharge. The results show that the production characteristics of reactive species are strongly influenced by the total gas number density and the higher concentration of reactive species are produced at higher pressure and lower gas temperature for a given initial reduced electric field.

Takana, H.; Tanaka, Y.; Nishiyama, H.

2012-01-01

58

State-to-state three-atom time-dependent reactive scattering in hyperspherical coordinates.  

PubMed

We present a time-dependent, hyperspherical wave packet method for calculating three-atom state-to-state S-matrix elements. The wave packet is propagated in time using adiabatically adjusting, principal axes hyperspherical coordinates that treat all arrangement channels equivalently, allowing the simultaneous analysis of the products in all three arrangement channels. We take advantage of the symmetry of the potential energy surface and decompose the initial wave packet into its component irreducible representations, propagating each component separately. Each irreducible representation component of the wave packet is analyzed by projecting it onto the hyperspherical basis at a fixed, asymptotic hyperradius, and irreducible representation dependent S-matrix elements are obtained by matching the hyperspherical projections to symmetry-adapted Jacobi coordinate boundary conditions. We obtain arrangement channel-dependent S-matrix elements as linear combinations of the irreducible representation dependent elements. State-to-state H + H(2) and F + H(2) results for zero total angular momentum are presented. PMID:23406125

Crawford, Jeff; Parker, Gregory A

2013-02-01

59

Production of Reactive Oxygen Species from Dissolved Organic Matter Photolysis in Ice  

NASA Astrophysics Data System (ADS)

Dissolved natural organic matter (DOM) is a ubiquitous component of natural waters and an important photosensitizer. A variety of reactive oxygen species (ROS) are known to be produced from DOM photolysis including singlet oxygen, hydroxyl radical, peroxyl radical, etc. Recently, it has been determined that organic material is one of the largest contributors to sunlight absorption in snowpack, however DOM photochemistry in snow/ice has received little attention in the literature. The production of ROS from DOM photolysis in snow/ice could play an important role in snowpack photochemical processes, degradation of pollutants in snowpack, and generation of volatile organic compounds emitted from snowpack. We have investigated ROS production from DOM in frozen aqueous solutions, using commercially available humic and fulvic acids. Here we will discuss the rates of ROS production in both liquid and frozen systems, differences in reactivity amongst the DOM sources studied (Suwannee River Humic Acid, Suwannee River Fulvic Acid, and Pony Lake Fulvic Acid), and the potential implications for snowpack photochemical processes.

Fede, A.; Grannas, A. M.

2012-12-01

60

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

NASA Astrophysics Data System (ADS)

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

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

2011-03-01

61

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

NASA Astrophysics Data System (ADS)

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

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

2011-05-01

62

Mitochondrial uncoupling does not decrease reactive oxygen species production after ischemia-reperfusion.  

PubMed

Cardiac ischemia-reperfusion (IR) leads to myocardial dysfunction by increasing production of reactive oxygen species (ROS). Mitochondrial H(+) leak decreases ROS formation; it has been postulated that increasing H(+) leak may be a mechanism of decreasing ROS production after IR. Ischemic preconditioning (IPC) decreases ROS formation after IR, but the mechanism is unknown. We hypothesize that pharmacologically increasing mitochondrial H(+) leak would decrease ROS production after IR. We further hypothesize that IPC would be associated with an increase in the rate of H(+) leak. Isolated male Sprague-Dawley rat hearts were subjected to either control or IPC. Mitochondria were isolated at end equilibration, end ischemia, and end reperfusion. Mitochondrial membrane potential (m??) was measured using a tetraphenylphosphonium electrode. Mitochondrial uncoupling was achieved by adding increasing concentrations of FCCP. Mitochondrial ROS production was measured by fluorometry using Amplex-Red. Pyridine dinucleotide levels were measured using HPLC. Before IR, increasing H(+) leak decreased mitochondrial ROS production. After IR, ROS production was not affected by increasing H(+) leak. H(+) leak increased at end ischemia in control mitochondria. IPC mitochondria showed no change in the rate of H(+) leak throughout IR. NADPH levels decreased after IR in both IPC and control mitochondria while NADH increased. Pharmacologically, increasing H(+) leak is not a method of decreasing ROS production after IR. Replenishing the NADPH pool may be a means of scavenging the excess ROS thereby attenuating oxidative damage after IR. PMID:25085966

Quarrie, Ricardo; Lee, Daniel S; Reyes, Levy; Erdahl, Warren; Pfeiffer, Douglas R; Zweier, Jay L; Crestanello, Juan A

2014-10-01

63

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

PubMed Central

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

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

2010-01-01

64

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

PubMed

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

Elias, Zoé; Poirot, Odile; Fenoglio, Ivana; Ghiazza, Mara; Danière, Marie-Céleste; Terzetti, Francine; Darne, Christian; Coulais, Catherine; Matekovits, Ildiko; Fubini, Bice

2006-06-01

65

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

PubMed Central

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 body’s 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

Rossoni-Júnior, Joamyr Victor; Araújo, Glaucy Rodrigues; Pádua, Bruno da Cruz; Chaves, Míriam Martins; Pedrosa, Maria Lúcia; Silva, Marcelo Eustáquio; Costa, Daniela Caldeira

2012-01-01

66

Evanescent acoustic waves: Production and scattering by resonant targets  

NASA Astrophysics Data System (ADS)

Small targets with acoustic resonances which may be excited by incident acoustic planewaves are shown to possess high-Q modes ("organ-pipe" modes) which may be suitable for ocean-based calibration and ranging purposes. The modes are modeled using a double point-source model; this, along with acoustic reciprocity and inversion symmetry, is shown to adequately model the backscattering form functions of the modes at low frequencies. The backscattering form-functions are extended to apply to any bistatic acoustic experiment using the targets when the target response is dominated by the modes in question. An interface between two fluids which each approximate an unbounded half-space has been produced in the laboratory. The fluids have different sound speeds. When sound is incident on this interface at beyond the critical angle from within the first fluid, the second fluid is made to evince a region dominated by evanescent acoustic energy. Such a system is shown to be an possible laboratory-based proxy for a flat sediment bottom in the ocean, or sloped (unrippled) bottom in littoral environments. The evanescent sound field is characterized and shown to have complicated features despite the simplicity of its production. Notable among these features is the presence of dips in the soundfield amplitude, or "quasi-nulls". These are proposed to be extremely important when considering the return from ocean-based experiments. The soundfield features are also shown to be accurately predicted and characterized by wavenumber-integration software. The targets which exhibit organ-pipe modes in the free-field are shown to also be excited by the evanescent waves, and may be used as soundfield probes when the target returns are well characterized. Alternately, if the soundfield is well-known, the target parameters may be extracted from back- or bistatic-scattering experiments in evanescent fields. It is shown that the spatial decay rate as measured by a probe directly in the evanescent field is half that as measured by backscattering experiments on horizontal and vertical cylinders driven at the fundamental mode, and it is demonstrated that this is explained by the principle of acoustic reciprocity.

Osterhoudt, Curtis F.

67

Cyp1a2 protects against reactive oxygen production in mouse liver microsomes.  

PubMed

H(2)O(2) production was evaluated in liver microsomes prepared from Cyp1a1/1a2(+/+) wild-type and Cyp1a1(-/-) and Cyp1a2(-/-) knockout mice pretreated with 5 microg dioxin (TCDD)/kg body wt or vehicle alone. NADPH-dependent H(2)O(2) production in TCDD-induced microsomes from wild-type mice was about one-third of that in noninduced microsomes. In Cyp1a2(-/-) mice, H(2)O(2) production was the same for induced and noninduced microsomes, with levels significantly higher than those in wild-type mice. Cyp1a1(-/-) microsomes displayed markedly lower levels of H(2)O(2) production in both induced and noninduced microsomes, compared with those in wild-type and Cyp1a2(-/-) microsomes. The CYP1A2 inhibitor furafylline in vitro exacerbated microsomal H(2)O(2) production proportional to the degree of CYP1A2 inhibition, and the CYP2E1 inhibitor diethyldithiocarbamate decreased H(2)O(2) production proportional to the degree of CYP2E1 inhibition. Microsomal H(2)O(2) production was strongly correlated to NADPH-stimulated production of thiobarbituric acid-reactive substances, as well as to decreases in microsomal membrane polarization anisotropy, indicative of peroxidation of unsaturated membrane lipids. Our results suggest that possibly acting as an "electron sink," CYP1A2 might decrease CYP2E1-and CYP1A1-mediated H(2)O(2) production and oxidative stress. In this regard, CYP1A2 may be considered an antioxidant enzyme. PMID:14980704

Shertzer, Howard G; Clay, Corey D; Genter, Mary Beth; Schneider, Scott N; Nebert, Daniel W; Dalton, Timothy P

2004-03-01

68

Mitochondrial metabolic suppression in fasting and daily torpor: consequences for reactive oxygen species production.  

PubMed

Abstract Daily torpor results in an ?70% decrease in metabolic rate (MR) and a 20%-70% decrease in state 3 (phosphorylating) respiration rate of isolated liver mitochondria in both dwarf Siberian hamsters and mice even when measured at 37°C. This study investigated whether mitochondrial metabolic suppression also occurs in these species during euthermic fasting, when MR decreases significantly but torpor is not observed. State 3 respiration rate measured at 37°C was 20%-30% lower in euthermic fasted animals when glutamate but not succinate was used as a substrate. This suggests that electron transport chain complex I is inhibited during fasting. We also investigated whether mitochondrial metabolic suppression alters mitochondrial reactive oxygen species (ROS) production. In both torpor and euthermic fasting, ROS production (measured as H(2)O(2) release rate) was lower with glutamate in the presence (but not absence) of rotenone when measured at 37°C, likely reflecting inhibition at or upstream of the complex I ROS-producing site. ROS production with succinate (with rotenone) increased in torpor but not euthermic fasting, reflecting complex II inhibition during torpor only. Finally, mitochondrial ROS production was twofold more temperature sensitive than mitochondrial respiration (as reflected by Q(10) values). These data suggest that electron leak from the mitochondrial electron transport chain, which leads to ROS production, is avoided more efficiently at the lower body temperatures experienced during torpor. PMID:21897084

Brown, Jason C L; Staples, James F

2011-01-01

69

Measurement of hadron production in Deep Inelastic Scattering  

E-print Network

. The measurements provide sensitive tests for the initial state parton radiation process as well in deep in- elastic scattering is a sensitive probe to parton radiation at the high pT tail to the current hemisphere and particles with proton remnant) hemisphere (Fig.1

Heller, Barbara

70

Mitochondrial production of reactive oxygen species contributes to the ?-adrenergic stimulation of mouse cardiomycytes  

PubMed Central

Abstract The sympathetic adrenergic system plays a central role in stress signalling and stress is often associated with increased production of reactive oxygen species (ROS). Furthermore, the sympathetic adrenergic system is intimately involved in the regulation of cardiomyocyte Ca2+ handling and contractility. In this study we hypothesize that endogenously produced ROS contribute to the inotropic mechanism of ?-adrenergic stimulation in mouse cardiomyocytes. Cytoplasmic Ca2+ transients, cell shortening and ROS production were measured in freshly isolated cardiomyocytes using confocal microscopy and fluorescent indicators. As a marker of oxidative stress, malondialdehyde (MDA) modification of proteins was detected with Western blotting. Isoproterenol (ISO), a ?-adrenergic agonist, increased mitochondrial ROS production in cardiomyocytes in a concentration- and cAMP–protein kinase A-dependent but Ca2+-independent manner. Hearts perfused with ISO showed a twofold increase in MDA protein adducts relative to control. ISO increased Ca2+ transient amplitude, contraction and L-type Ca2+ current densities (measured with whole-cell patch-clamp) in cardiomyocytes and these increases were diminished by application of the general antioxidant N-acetylcysteine (NAC) or the mitochondria-targeted antioxidant SS31. In conclusion, increased mitochondrial ROS production plays an integral role in the acute inotropic response of cardiomyocytes to ?-adrenergic stimulation. On the other hand, chronically sustained adrenergic stress is associated with the development of heart failure and cardiac arrhythmias and prolonged increases in ROS may contribute to these defects. PMID:21486840

Andersson, Daniel C; Fauconnier, Jérémy; Yamada, Takashi; Lacampagne, Alain; Zhang, Shi-Jin; Katz, Abram; Westerblad, Håkan

2011-01-01

71

Effects of Hepatitis C core protein on mitochondrial electron transport and production of reactive oxygen species  

PubMed Central

Viral infections frequently alter mitochondrial function with suppression or induction of apoptosis and enhanced generation of reactive oxygen species. The mechanisms of these effects are varied and mitochondria are affected by both direct interactions with viral proteins as well as by secondary effects of viral activated signaling cascades. This chapter describes methods used in our laboratory to assess the effects of the Hepatitis C virus core protein on mitochondrial ROS production, electron transport and Ca2+ uptake. These include measurements of the effects of in vitro incubation of liver mitochondria with purified core protein as well as assessment of the function of mitochondria in cells and tissues expressing core and other viral proteins. These methods are generally applicable to the study of viral-mitochondrial interactions. PMID:19348899

Campbell, Roosevelt V.; Yang, Yuanzheng; Wang, Ting; Rachamallu, Aparna; Li, Yanchun; Watowich, Stanley J.; Weinman, Steven A.

2014-01-01

72

Reactive oxygen species production and activation mechanism of the rice NADPH oxidase OsRbohB.  

PubMed

Reactive oxygen species (ROS) produced by plant NADPH oxidases (NOXes) are important in plant innate immunity. The Oryza sativa respiratory burst oxidase homologue B (OsRbohB) gene encodes a NOX the regulatory mechanisms of which are largely unknown. Here, we used a heterologous expression system to demonstrate that OsRbohB shows ROS-producing activity. Treatment with ionomycin, a Ca(2+) ionophore, and calyculin A, a protein phosphatase inhibitor, activated ROS-producing activity; it was thus OsRbohB activated by both Ca(2+) and protein phosphorylation. Mutation analyses revealed that not only the first EF-hand motif but also the upstream amino-terminal region were necessary for Ca(2+)-dependent activation, while these regions are not required for phosphorylation-induced ROS production. PMID:22528669

Takahashi, Shinya; Kimura, Sachie; Kaya, Hidetaka; Iizuka, Ayako; Wong, Hann Ling; Shimamoto, Ko; Kuchitsu, Kazuyuki

2012-07-01

73

The Endogenous Production of Reactive Oxygen Species Is Required For Stimulation of Human Articular Chondrocyte MMP Production by Fibronectin Fragments  

PubMed Central

The objective of the present study was to determine if reactive oxygen species (ROS) are required as secondary messengers for fibronectin fragment stimulated matrix metalloproteinase (MMP) production in human articular chondrocytes. Cultured cells were stimulated with 25?g/ml of the ?5?1 integrin-binding 110kDa fibronectin fragment (FN-f) in the presence and absence of various antioxidants including Mn(III) tetrakis(4-benzoic acid)porphyrin (MnTBAP). FN-f stimulation significantly increased intracellular levels of ROS in articular chondrocytes. Pretreatment of cells with 250?M MnTBAP or 40mM N-Acetyl-L-cysteine, but not inhibitors of nitric oxide synthase, completely prevented FN-f stimulated MMP-3, -10 and -13 production. MnTBAP also blocked FN-f induced phosphorylation of the MAP kinases and NF-?B-associated proteins and blocked activation of an NF-?B promoter-reporter construct. Overexpression of catalase, superoxide dismutase, or glutathione peroxidase also inhibited FN-f stimulated MMP-13 production. Pre-incubation of chondrocytes with rotenone, an inhibitor of the mitochondrial electron transport chain, or nordihydroguaiaretic acid (NDGA), a selective 5-lipoxygenase inhibitor, partially prevented FN-f stimulated MMP-13 production and decreased MAP kinase and NF-?B phosphorylation. These results show that increased production of ROS but not nitric oxide are obligatory secondary messengers in the chondrocyte FN-f signaling pathway that leads to the increased production of MMPs, including MMP-13. PMID:17395008

Del Carlo, Marcello; Schwartz, Daniel; Erickson, Elizabeth A.; Loeser, Richard F.

2007-01-01

74

Reactive Oxygen Species Production in Energized Cardiac Mitochondria During Hypoxia/Reoxygenation: Modulation by Nitric Oxide  

PubMed Central

Mitochondria are an important source of reactive oxygen species (ROS) implicated in ischemia/reperfusion injury. When isolated from ischemic myocardium, mitochondria demonstrate increased ROS production as a result of damage to electron transport complexes. To investigate the mechanisms, we studied effects of hypoxia/reoxygenation on ROS production by isolated energized heart mitochondria. ROS production, tracked using Fe2+-catalyzed, H2O2-dependent H2DCF oxidation or Amplex Red, was similar during normoxia and hypoxia, but markedly increased during reoxygenation, in proportion to the duration of hypoxia. In contrast, if mitochondria were rapidly converted from normoxia to near-anoxia ([O2]< 1 ?M), the increase in H2DCF oxidation rate during reoxygenation was markedly blunted. To elicit the robust increase in H2DCF oxidation rate during reoxygenation, hypoxia had to be severe enough to cause partial, but not complete, respiratory chain inhibition (as shown by partial dissipation of membrane potential and increased NADH auto-fluorescence). Consistent with its cardioprotective actions, nitric oxide (•NO) abrogated increased H2DCF oxidation under these conditions, as well as attenuating ROS-induced increases in matrix [Fe2+] and aconitase inhibition caused by antimycin. Collectively, these results suggest that a) hypoxia sufficient to cause partial respiratory inhibition is more damaging to mitochondria than near-anoxia; b) •NO suppresses ROS-induced damage to electron transport complexes, probably by forming •NO-Fe2+ complexes in the presence of glutathione which inhibit hydroxyl radical formation. PMID:18776040

Korge, Paavo; Ping, Peipei; Weiss, James N

2009-01-01

75

Production of reactive oxygen species after photodynamic therapy by porphyrin sensitizers.  

PubMed

The objectives of this study was to investigate the production of reactive oxygen species (ROS) after photodynamic therapy (PDT) in vitro. We examined second generation sensitizers, porphyrines (TPPS4, ZnTPPS4 and PdTPPS4) and compared their effectivity on ROS generation in G361 cell line. Used porphyrines are very efficient water-soluble aromatic dyes with potential to use in photomedicine and have a high propensity to accumulate in the membranes of intracellular organelles like lysosomes and mitochondria. Interaction between the triplet excited state of the sensitizer and molecular oxygen leads to produce singlet oxygen and other ROS to induce cell death. Production of ROS was verificated by molecular probe CM-H2DCFDA and viability of cells was determined by MTT assay. Our results demonstrated that ZnTPPS4 induces the highest ROS production in cell line compared to TPPS4 and PdTPPS4 at each used concentration and light dose. These results consist with a fact that photodynamic effect depends on sensitizer type, its concentration and light dose. PMID:18645224

Kolarova, H; Nevrelova, P; Tomankova, K; Kolar, P; Bajgar, R; Mosinger, J

2008-06-01

76

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

PubMed Central

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

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

2009-01-01

77

Production of reactive oxygen species by man-made vitreous fibres in human polymorphonuclear leukocytes.  

PubMed

Human polymorphonuclear leukocytes (PMNL) or erythrocytes, isolated from human blood, were exposed to graded doses of asbestos (chrysotile), quartz, or man-made vitreous fibres (MMVF), i.e. refractory ceramic fibres (RCF), glasswool, or rockwool fibres. None of the MMVF affected either the viability of PMNL, as measured by trypan blue exclusion test, or induced haemolysis, whereas the positive controls, quartz and chrysotile, dose-dependently induced haemolysis in PMNL. MMVF did not increase the release of lactate dehydrogenase (LDH) from the PMNL, whereas the positive controls, chrysotile and quartz, induced a marked and dose-dependent release of LDH. When PMNL were exposed to MMVF, some of the fibre types slightly increased the levels of free intracellular calcium ([Ca2+]i) within the cells in a manner similar to that induced by chrysotile or quartz. All MMVF induced a dose-dependent production of reactive oxygen species (ROS) in PMNL, with RCF-induced production of ROS being the most marked. Production of ROS by MMVF seemed to depend on the availability of extracellular calcium because it could be attenuated with a Ca2+ channel blocker, verapamil, or a Ca2+ chelating agent, EGTA. Production of ROS may be a common pathway through which PMNL respond to MMVF-induced cell activation, but alterations of levels of free intracellular Ca2+ do not seem to be an absolute prerequisite for this effect. Fibre length seemed not to be an important factor in affecting the ability of MMVF to induce ROS production in PMNL. However, the balance between different elements in the fibre seemed importantly to affect the biological activity of a fibre. PMID:10413242

Ruotsalainen, M; Hirvonen, M R; Luoto, K; Savolainen, K M

1999-06-01

78

Analysis of acidity production during enhanced reductive dechlorination using a simplified reactive transport model  

NASA Astrophysics Data System (ADS)

Build-up of fermentation products and hydrochloric acid at a contaminated site undergoing enhanced reductive dechlorination can result in groundwater acidification. Sub-optimal pH conditions can inhibit microbial activity and lead to reduced dechlorination rates. The extent of acidification likely to occur is site-specific and depends primarily on the extent of fermentation and dechlorination, the geochemical composition of soil and groundwater, and the pH-sensitivity of the active microbial populations. Here, the key chemical and physical mechanisms that control the extent of groundwater acidification in a contaminated site were examined, and the extent to which the remediation efficiency was affected by variations in groundwater pH was evaluated using a simplified process-based reactive-transport model. This model was applied successfully to a well-documented field site and was then employed in a sensitivity analysis to identify the processes likely to significantly influence acidity production and subsequent microbial inhibition. The accumulation of organic acids produced from the fermentation of the injected substrate was the main cause of the pH change. The concentration of dissolved sulphates controlled substrate utilisation efficiency because sulphate-reducing biomass competed with halo-respiring biomass for the fermentation products. It was shown further that increased groundwater velocity increases dilution and reduces the accumulation of acidic products. As a consequence, the flow rate corresponding to the highest remediation efficiency depends on the fermentation and dechlorination rates. The model enables investigation and forecasting of the extent and areal distribution of pH change, providing a means to optimise the application of reductive dechlorination for site remediation.

Brovelli, A.; Barry, D. A.; Robinson, C.; Gerhard, J. I.

2012-07-01

79

Loss of caspase-2 accelerates age-dependent alterations in mitochondrial production of reactive oxygen species.  

PubMed

Mitochondria are known to be a major source and target of oxidative stress. Oxidative stress increases during aging and is suggested to underlie in part the aging process. We have previously documented an increase in endogenous caspase-2 (casp2) activity in hepatocytes obtained from old (28 months) vs. young mice (5 months). More recently, we have shown that casp2 is activated by oxidative stress and is critical for mitochondrial oxidative stress-induced apoptosis. Since casp2 appears integral to mitochondrial oxidative stress-induced apoptosis, in this study we determined whether loss of casp2 altered the production of mitochondrial reactive oxygen radicals (mROS) as a function of age in intact living hepatocytes. To stimulate mitochondrial metabolic activity, we added a mixture of pyruvate and glutamate to hepatocytes while continuously monitoring endogenous mROS production in the presence or absence of rotenone and/or antimycin A. Our data demonstrate that mROS production and neutralization are compromised in hepatocytes of old mice. Interestingly, casp2 deficient hepatocytes from middle age mice (12 months) had similar mROS neutralization kinetics to those of hepatocytes from old WT mice. Rotenone had no effect on mROS metabolism, whereas antimycin A significantly altered mROS production and metabolism in an age-dependent fashion. Our results indicate that: (1) hepatocytes from young and old mice respond differently to dysfunction of the mitochondrial electron transport chain; (2) age-dependent alterations in mROS metabolism are likely regulated by complex III; and (3) absence of casp2 accelerates age-dependent changes in terms of pyruvate/glutamate-induced mROS metabolism. PMID:23504374

Lopez-Cruzan, Marisa; Herman, Brian

2013-04-01

80

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

PubMed

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

Cho, Kangwoo; Hoffmann, Michael R

2014-10-01

81

Conversion of Natively Unstructured ?-Synuclein to Its ?-Helical Conformation Significantly Attenuates Production of Reactive Oxygen Species  

PubMed Central

The intracellular ?-synuclein (?-syn) protein, whose conformational change and aggregation have been closely linked to the pathology of Parkingson’s disease (PD), is highly populated at the presynaptic termini and remains there in the ?-helical conformation. In this study, circular dichroism confirmed that natively unstructured ?-syn in aqueous solution was transformed to its ?-helical conformation upon addition of trifluoroethanol (TFE). Electrochemical and UV–visible spectroscopic experiments reveal that both Cu(I) and Cu(II) are stabilized, with the former being stabilized by about two orders of magnitude. Compared to unstructured ?-syn (Binolfi et al., J. Am. Chem. Soc. 133 (2011) 194–196), ?-helical ?-syn stabilizes Cu(I) by more than three orders of magnitude. Through the measurements of H2O2 and hydroxyl radicals (OH•) in solutions containing different forms of Cu(II) (free and complexed by unstructured or ?-helical ?-syn), we demonstrate that the significantly enhanced Cu(I) binding affinity helps inhibit the production of highly toxic reactive oxygen species, especially the hydroxyl radicals. Our study provides strong evidence that, as a possible means to prevent neuronal cell damage, conversion of the natively unstructured ?-syn to its ?-helical conformation in vivo could significantly attenuate the copper-modulated ROS production. PMID:23123341

Zhou, Binbin; Hao, Yuanqiang; Wang, Chengshan; Li, Ding; Liu, You-Nian; Zhou, Feimeng

2012-01-01

82

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

E-print Network

We analyze the high energy scattering of hadrons in QCD in an effective theory model inspired from a gravity dual description. The nucleons are skyrmion-like solutions of a DBI action, and boosted nucleons give pions field shockwaves necessary for the saturation of the Froissart bound. Nuclei are analogs of BIon crystals, with the DBI skyrmions forming a fluid with a fixed inter-nucleon distance. In shockwave collisions one creates scalar (pion field) ``fireballs'' with horizons of nonzero temperature, whose scaling with mass we calculated. They are analogous to the hydrodynamic ``dumb holes,'' and their thermal horizons are places where the pion field becomes apparently singular. The information paradox becomes then a purely field theoretic phenomenon, not directly related to quantum gravity (except via AdS-CFT).

Horatiu Nastase

2005-12-14

83

Jet production in high Q 2 deep-inelastic ep scattering at HERA  

Microsoft Academic Search

Two-jet production in deep-inelastic electron-proton scattering has been studied for 160Q22, 0.01xy<0.95 with the ZEUS detector at HERA. The kinematic properties of the jets and the jet production rates are presented. The partonic scaling variables of the two-jet system and the rate of two-jet production are compared to perturbative next-to-leading order QCD calculations.

M. Derrick; D. Krakauer; S. Magill; D. Mikunas; B. Musgrave; J. Repond; R. Stanek; R. L. Talaga; H. Zhang; R. Avad; G. Bari; M. Basile; L. Bellagamba; D. Boscherini; A. Bruni; G. Bruni; P. Bruni; G. Cara Romeo; G. Castellini; M. Chiarini; L. Cifarelli; F. Cindolo; A. Contin; M. Corradi; I. Gialas; P. Giusti; G. Iacobucci; G. Laurenti; G. Levi; A. Margotti; T. Massam; R. Nania; C. Nemoz; E. Palmonari; A. Polini; G. Sartorelli; R. Timellini; Y. Zamora Garcia; A. Zichichi; A. Bargende; J. Crittenden; K. Desch; B. Diekmann; T. Doeker; M. Eckert; L. Feld; A. Frey; M. Geerts; G. Geitz; M. Grothe; T. Haas; H. Hartmann; D. Haun; K. Heinloth; E. Hilger; H.-P. Jakob; U. F. Katz; S. M. Mari; A. Mass; S. Mengel; J. Mollen; E. Paul; Ch. Rembser; R. Schattevoy; D. Schramm; J. Stamm; R. Wedemeyer; S. Campbell-Robson; A. Cassidy; N. Dyce; B. Foster; S. George; R. Gilmore; G. P. Heath; H. F. Heath; T. J. Llewellyn; C. J. S. Morgado; D. J. P. Norman; J. A. O'Mara; R. I. Tapper; S. S. Wilson; R. Yoshida; R. R. Rau; M. Arneodo; L. Iannotti; M. Schioppa; G. Susinno; A. Bernstein; A. Caldwell; J. A. Parsons; S. Ritz; F. Sciulli; P. B. Straub; L. Wai; S. Yang; Q. Zhu; P. Borzemski; J. Chwastowski; A. Eskreys; K. Piotrzkowski; M. Zachara; L. Zawiejski; L. Adamczyk; B. Bednarek; K. Eskreys; K. Jele?; D. Kisielewska; T. Kowalski; E. Rulikowska-Zar?bska; L. Suszycki; J. Zaj?c; A. Kota?ski; M. Przybycie?; I. A. T. Bauerdick; U. Behrens; H. Beier; J. K. Bienlein; C. Coldewey; O. Deppe; K. Desler; G. Drews; M. Flasi?ski; D. J. Gilkinson; C. Glasman; P. Göttlicher; J. Große-Knetter; B. Gutjahr; W. Hain; D. Hasell; H. Heßling; H. Hultschig; Y. Iga; P. Joos; M. Kasemann; R. Klanner; W. Koch; L. Köpke; U. Kötz; H. Kowalski; J. Labs; A. Ladage; B. Löhr; M. Löwe; D. Lüke; O. Ma?czak; J. S. T. Ng; S. Nickel; D. Notz; K. Ohrenberg; M. Roco; M. Rohde; J. Roldán; U. Schneekloth; W. Schulz; F. Selonke; E. Stiliaris; B. Surrow; T. Voß; D. Westphal; G. Wolf; C. Youngman; J. F. Zhou; H. J. Grabosch; A. Kharchilava; A. Leich; M. Mattingly; A. Meyer; S. Schlenstedt; N. Wulff; G. Barbagli; P. Pelfer; G. Anzivino; G. Maccarrone; S. De Pasquale; L. Votano; A. Bamberger; S. Eisenhardt; A. Freidhof; S. Söldner-Rembold; J. Schroeder; T. Trefzger; N. H. Brook; P. J. Bussey; A. T. Doyle; I. Fleck; D. H. Saxon; M. L. Utley; A. S. Wilson; A. Dannemann; U. Holm; D. Horstmann; T. Neumann; R. Sinkus; K. Wick; E. Badura; B. D. Burow; L. Hagge; E. Lohrmann; J. Mainusch; J. Milewski; M. Nakahata; N. Pavel; G. Poelz; W. Schott; F. Zetsche; T. C. Bacon; I. Butterworth; E. Gallo; V. L. Harris; B. Y. H. Hung; K. R. Long; D. B. Miller; P. P. O. Morawitz; A. Prinias; J. K. Sedgbeer; A. F. Whitfield; U. Mallik; E. McCliment; M. Z. Wang; S. M. Wang; J. T. Wu; Y. Zhang; P. Cloth; D. Filges; S. H. An; S. M. Hong; S. W. Nam; S. K. Park; M. H. Suh; S. H. Yon; R. Imlay; S. Kartik; H.-J. Kim; R. R. McNeil; W. Metcalf; V. K. Nadendla; F. Barreiro; G. Cases; R. Graciani; J. M. Hernández; L. Hervás; L. Labarga; J. del Peso; J. Puga; J. Terron; J. F. de Trocóniz; G. R. Smith; F. Corriveau; D. S. Hanna; J. Hartmann; L. W. Hung; J. N. Lim; C. G. Matthews; P. M. Patel; L. E. Sinclair; D. G. Stairs; M. St. Laurent; R. Ullmann; G. Zacek; V. Bashkirov; B. A. Dolgoshein; A. Stifutkin; G. L. Bashindzhagyan; P. F. Ermolov; L. K. Gladilin; Y. A. Golubkov; V. D. Kobrin; V. A. Kuzmin; A. S. Proskuryakov; A. A. Savin; L. M. Shcheglova; A. N. Solomin; N. P. Zotov; M. Botje; F. Chlebana; A. Dake; J. Engelen; M. de Kamps; P. Kooijman; A. Kruse; H. Tiecke; W. Verkerke; M. Vreeswijk; L. Wiggers; E. de Wolf; R. van Woudenberg; D. Acosta; B. Bylsma; L. S. Durkin; K. Honscheid; C. Li; T. Y. Ling; K. W. McLean; W. N. Murray; I. H. Park; T. A. Romanowski; R. Seidlein; D. S. Bailey; G. A. Blair; A. Byrne; R. J. Cashmore; A. M. Cooper-Sarkar; D. Daniels; R. C. E. Devenish; N. Harnew; M. Lancaster; P. E. Luffman; L. Lindemann; J. D. McFall; C. Nath; V. A. Noyes; A. Quadt; H. Uijterwaal; R. Walczak; F. F. Wilson; T. Yip; G. Abbiendi; A. Bertolin; R. Brugnera; R. Carlin; F. Dal Corso; M. De Giorgi; U. Dosselli; S. Limentani; M. Morandin; M. Posocco; L. Stanco; R. Stroili; C. Voci; J. Bulmahn; J. M. Butterworth; R. G. Feild; B. Y. Oh; J. J. Whitmore; G. D'Agostini; G. Marini; A. Nigro; E. Tassi; J. C. Hart; N. A. McCubbin; K. Prytz; T. P. Shah; T. L. Short; L. Barberis; N. Cartiglia; T. Dubbs; C. Heusch; M. Van Hook; B. Hubbard; W. Lockman; J. T. Rahn; H. F.-W. Sadrozinski; A. Seiden; J. Biltzinger; R. J. Seifert; A. H. Walenta; G. Zech; H. Abramowicz; G. Briskin; S. Dagan; A. Levy; T. Hasegawa; M. Hazumi; T. Ishii; M. Kuze; S. Mine; Y. Nagasawa; M. Nakao; I. Suzuki; K. Tokushuku; S. Yamada; Y. Yamazaki; M. Chiba; R. Hamatsu; T. Hirose; K. Homma; S. Kitamura; Y. Nakamitsu; K. Yamauchi; R. Cirio; M. Costa; M. I. Ferrero; L. Lamberti; S. Maselli; C. Peroni

1995-01-01

84

The Theory and Selection of Chemically Reactive Tracers for Reservoir Thermal Capacity Production  

SciTech Connect

The theory behind how chemically reactive tracers are used to characterize the velocity and temperature distribution in steady flowing systems is reviewed. Ranges of kinetic parameters are established as a function of reservoir temperatures and fluid residence times for selecting appropriate reacting systems. Reactive tracer techniques are applied to characterize the temperature distribution in a laminar-flow heat exchanger. Models are developed to predict reactive tracer behavior in fractured geothermal reservoirs of fixed and increasing size. 5 figs., 11 refs.

Tester, Jefferson W.; Robinson, Bruce A.; Ferguson, James

1987-01-20

85

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

PubMed

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

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

2012-08-01

86

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

PubMed

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 3-5 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

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

2015-01-01

87

Positron production in multiphoton light-by-light scattering  

SciTech Connect

A signal of 106 {+-} 14 positrons above background has been observed in collisions of a low-emittance 46.6-GeV electron beam with terawatt pulses from a Nd:glass laser at 527 nm wavelength in an experiment at the Final Focus Test Beam at SLAC. Peak laser intensities of {approximately} 1.3 {times} 10{sup 18} W/cm{sup 2} have been achieved corresponding to a value of 0.3 for the parameter {Upsilon} = {var_epsilon}*/{var_epsilon}{sub crit} where {var_epsilon}* = 2{gamma}{var_epsilon}{sub lab} is the electric field strength of the laser transformed to the rest frame of the electron beam and {var_epsilon}{sub crit} = m{sup 2}c{sup 3}/e{bar h} = 1.3 {times} 10{sup 16} V/cm is the QED critical field strength. The positrons are interpreted as arising from a two-step process in which laser photons are backscattered to GeV energies by the electron beam followed by a collision between the high-energy photon and several laser photons to produce an electron-positron pair. These results are the first laboratory evidence for a light-by-light scattering process involving only real photons.

Bula, C. [Princeton Univ., NJ (United States). Joseph Henry Labs.; E-144 Collaboration

1997-03-01

88

Autophagy proteins control goblet cell function by potentiating reactive oxygen species production  

PubMed Central

Delivery of granule contents to epithelial surfaces by secretory cells is a critical physiologic process. In the intestine, goblet cells secrete mucus that is required for homeostasis. Autophagy proteins are required for secretion in some cases, though the mechanism and cell biological basis for this requirement remain unknown. We found that in colonic goblet cells, proteins involved in initiation and elongation of autophagosomes were required for efficient mucus secretion. The autophagy protein LC3 localized to intracellular multi-vesicular vacuoles that were consistent with a fusion of autophagosomes and endosomes. Using cultured intestinal epithelial cells, we found that NADPH oxidases localized to and enhanced the formation of these LC3-positive vacuoles. Both autophagy proteins and endosome formation were required for maximal production of reactive oxygen species (ROS) derived from NADPH oxidases. Importantly, generation of ROS was critical to control mucin granule accumulation in colonic goblet cells. Thus, autophagy proteins can control secretory function through ROS, which is in part generated by LC3-positive vacuole-associated NADPH oxidases. These findings provide a novel mechanism by which autophagy proteins can control secretion. PMID:24185898

Patel, Khushbu K; Miyoshi, Hiroyuki; Beatty, Wandy L; Head, Richard D; Malvin, Nicole P; Cadwell, Ken; Guan, Jun-Lin; Saitoh, Tatsuya; Akira, Shizuo; Seglen, Per O; Dinauer, Mary C; Virgin, Herbert W; Stappenbeck, Thaddeus S

2013-01-01

89

Modulation of the production of reactive oxygen species by pre-activated neutrophils by aminoadamantane derivatives.  

PubMed

Aminoadamantane derivatives (AAD) such as amantadine or memantine have been used for the treatment of Morbus Parkinson and Morbus Alzheimer. In this communication, we report on the immunomodulatory activities of AAD. Luminol-dependent chemiluminescence of zymosan-, N-formylmethionylleucylphenylalanine(FMLP)- or experimental Ca2+-ionophore(A 231879)-preactivated polymorphonuclear leukocytes (PMN) was strongly enhanced by submicromolar concentrations of AAD and inhibited at higher concentrations than 0.1 mM. Light emission by phorbol-12-myristate-acetate(PMA)-preactivated cells was not further stimulated but inhibited by the elevated concentrations, just as with the other, above-mentioned activators. Ethylene formation from alpha-keto-methylthiobutyrate (KMB) as an indicator for production of OH.-type reactive oxygen species by the NADPH-oxidase ("respiratory burst") was augmented by AAD and completely inhibited by superoxide dismutase. In contrast, ethylene release from 1-amino-cyclopropyl-l-carboxylic acid (ACC) as relatively specific indicator for the myeloperoxidase reaction after degranulation was not influenced by AAD. As documented by several model reactions, AAD per se did not act as scavengers or quenchers of activated oxygen species such as superoxide, OH.-radical, hydrogen peroxide or hypochlorite. Altogether, these results suggest that submicromolar concentrations of AAD upregulate the respiratory burst, but apparently not the degranulation of prestimulated polymorphonuclear leukocytes. At higher concentrations of AAD, both respiratory burst and degranulation are inhibited, however. These effects can also be shown in complete blood samples. PMID:9698098

Albrecht-Goepfert, E; Schempp, H; Elstner, E F

1998-07-01

90

Feedback between p21 and reactive oxygen production is necessary for cell senescence  

PubMed Central

Cellular senescence—the permanent arrest of cycling in normally proliferating cells such as fibroblasts—contributes both to age-related loss of mammalian tissue homeostasis and acts as a tumour suppressor mechanism. The pathways leading to establishment of senescence are proving to be more complex than was previously envisaged. Combining in-silico interactome analysis and functional target gene inhibition, stochastic modelling and live cell microscopy, we show here that there exists a dynamic feedback loop that is triggered by a DNA damage response (DDR) and, which after a delay of several days, locks the cell into an actively maintained state of ‘deep' cellular senescence. The essential feature of the loop is that long-term activation of the checkpoint gene CDKN1A (p21) induces mitochondrial dysfunction and production of reactive oxygen species (ROS) through serial signalling through GADD45-MAPK14(p38MAPK)-GRB2-TGFBR2-TGF?. These ROS in turn replenish short-lived DNA damage foci and maintain an ongoing DDR. We show that this loop is both necessary and sufficient for the stability of growth arrest during the establishment of the senescent phenotype. PMID:20160708

Passos, João F; Nelson, Glyn; Wang, Chunfang; Richter, Torsten; Simillion, Cedric; Proctor, Carole J; Miwa, Satomi; Olijslagers, Sharon; Hallinan, Jennifer; Wipat, Anil; Saretzki, Gabriele; Rudolph, Karl Lenhard; Kirkwood, Tom B L; von Zglinicki, Thomas

2010-01-01

91

Effects of Pectic Polysaccharides Isolated from Leek on the Production of Reactive Oxygen and Nitrogen Species by Phagocytes  

PubMed Central

Abstract The current survey investigates the effect of four polysaccharides isolated from fresh leek or alcohol insoluble substances (AIS) of leek on the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) from phagocytes. The ability of the polysaccharides to activate serum complement was also investigated. Despite the lack of antioxidant activity, the pectic polysaccharides significantly decreased the production of ROS by human neutrophils. Polysaccharides isolated from AIS markedly activated RAW 264.7 macrophages for RNS production in a concentration-dependent manner. The Western blot analysis revealed that this effect was due to the stimulation of the inducible nitric oxide synthase protein expression of macrophages. The polysaccharides extracted from AIS with water showed the ability to fix serum complement, especially through the alternative pathway. It was found that the polysaccharide that has the highest complement-fixing effect is characterized by the highest content of uronic acids and the highest molecular weight. PMID:23905651

Nikolova, Mariana; Ambrozova, Gabriela; Kratchanova, Maria; Denev, Petko; Kussovski, Veselin; Ciz, Milan

2013-01-01

92

Coherent pion production by neutrino scattering off nuclei  

SciTech Connect

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.

Kartavtsev, A.; Paschos, E. A.; Gounaris, G. J. [Universitaet Dortmund, Institut fuer Physik, D-44221 Dortmund (Germany); Department of Theoretical Physics, Aristotle University of Thessaloniki, Gr-54124 Thessaloniki (Greece)

2006-09-01

93

Interactions of corrosion products and bentonite: An extended multicomponent reactive transport model  

NASA Astrophysics Data System (ADS)

Radioactive waste disposal in deep geological repositories envisages various engineered barriers such as carbon-steel canisters and compacted bentonite. Canister corrosion and the chemical interactions of corrosion products with bentonite are key reactions for the long term performance of a repository. Samper, Lu, and Montenegro (Physics and Chemistry of the Earth 2008; 33S: S306-S316) reported numerical models to simulate canister corrosion and the interactions of corrosion products with bentonite for the near field of a repository in granite. Here we present an updated version of their reactive transport model which accounts for: (1) Three types of sorption sites in the bentonite; (2) Kinetically-controlled canister corrosion, (3) Kinetically-controlled magnetite precipitation; and (4) The competition effect of Ni 2+ for sorbing sites. Accounting for kinetically-controlled canister corrosion leads to a significant reduction in the corrosion rate. Uncertainties in the surface complexation reactions play a minor role in the time evolution of the computed pH in the bentonite and the granite. Computed iron concentrations, however, are very sensitive to changes in the surface complexation reactions. The apparent distribution coefficient of Fe computed with the three-site model is 10 times larger than that obtained with a single-site model. The concentration of dissolved Fe computed with kinetic magnetite precipitation is smaller than that obtained with magnetite precipitation at local equilibrium. The largest difference in the concentration of dissolved Fe occurs after 3 × 10 4 years. The competition of Ni 2+ for sorption sites affects significantly the chemical evolution of the bentonite porewater. The sorption of Ni 2+ on bentonite releases protons and therefore the pH in the bentonite is smaller than that computed without Ni 2+ transport. The sorption of Ni 2+ leads to a decrease of the concentration of sorbed Fe and an increase of the concentration of dissolved Fe in the bentonite porewater for t < 10 5 years.

Lu, Chuanhe; Samper, Javier; Fritz, Bertrand; Clement, Alain; Montenegro, Luis

94

Reactive oxygen species production and redox state in parthenogenetic and sperm-mediated bovine oocyte activation.  

PubMed

The knowledge concerning redox and reactive oxygen species (ROS)-mediated regulation of early embryo development is scarce and remains controversial. The aim of this work was to determine ROS production and redox state during early in vitro embryo development in sperm-mediated and parthenogenetic activation of bovine oocytes. Sperm-mediated oocyte activation was carried out in IVF-modified synthetic oviductal fluid (mSOF) with frozen-thawed semen. Parthenogenetic activation was performed in TALP plus ionomycin and then in IVF-mSOF with 6-dimethylaminopurine plus cytochalasin B. Embryos were cultured in IVF-mSOF. ROS and redox state were determined at each 2-h interval (7-24?h from activation) by 2',7'-dichlorodihydrofluorescein diacetate and RedoxSensor Red CC-1 fluorochromes respectively. ROS levels and redox state differed between activated and non-activated oocytes (P<0.05 by ANOVA). In sperm-activated oocytes, an increase was observed between 15 and 19?h (P<0.05). Conversely, in parthenogenetically activated oocytes, we observed a decrease at 9?h (P<0.05). In sperm-activated oocytes, ROS fluctuated throughout the 24?h, presenting peaks around 7, 19, and 24?h (P<0.05), while in parthenogenetic activation, peaks were detected at 7, 11, and 17?h (P<0.05). In the present work, we found clear distinctive metabolic patterns between normal and parthenogenetic zygotes. Oxidative activity and ROS production are an integral part of bovine zygote behavior, and defining a temporal pattern of change may be linked with developmental competence. PMID:23630331

Morado, S; Cetica, P; Beconi, M; Thompson, J G; Dalvit, G

2013-05-01

95

Scoparone attenuates RANKL-induced osteoclastic differentiation through controlling reactive oxygen species production and scavenging.  

PubMed

Scoparone, one of the bioactive components of Artemisia capillaris Thunb, has various biological properties including immunosuppressive, hepatoprotective, anti-allergic, anti-inflammatory, and antioxidant effects. This study aims at evaluating the anti-osteoporotic effect of scoparone and its underlying mechanism in vitro. Scoparone demonstrated potent cellular antioxidant capacity. It was also found that scoparone inhibited the receptor activator of nuclear factor-?B ligand (RANKL)-induced osteoclast differentiation and suppressed cathepsin K and tartrate-resistant acid phosphatase (TRAP) expression via c-jun N-terminal kinase (JNK)/extracellular signal-regulated kinase (ERK)/p38-mediated c-Fos-nuclear factor of activated T cells, cytoplasmic 1 (NFATc1) signaling pathway. During osteoclast differentiation, the production of general reactive oxygen species (ROS) and superoxide anions was dose-dependently attenuated by scoparone. In addition, scoparone diminished NADPH (nicotinamide adenine dinucleotide phosphate) oxidase 1 (Nox1) expression and activation via the tumor necrosis factor receptor-associated factor 6 (TRAF6)-cSrc-phosphatidylinositol 3-kinase (PI3k) signaling pathway and prevented the disruption of mitochondrial electron transport chain system. Furthermore, scoparone augmented the expression of superoxide dismutase 1 (SOD1) and catalase (CAT). The overall results indicate that the inhibitory effect of scoparone on RANKL-induced osteoclast differentiation is attributed to the suppressive effect on ROS and superoxide anion production by inhibiting Nox1 expression and activation and protecting the mitochondrial electron transport chain system and the scavenging effect of ROS resulting from elevated SOD1 and CAT expression. PMID:25576385

Lee, Sang-Hyun; Jang, Hae-Dong

2015-02-15

96

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

SciTech Connect

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.

Jiang Bo; Hebert, Valeria Y. [Department of Pharmacology, Toxicology and Neuroscience, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA 71103 (United States); Li, Yuchi [Cardiopulmonary Research Institute, Winthrop University Hospital, State University of New York at Stony Brook School of Medicine, Mineola, NY 11501 (United States); Mathis, J. Michael [Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA 71103 (United States); Alexander, J. Steven [Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA 71103 (United States); Dugas, Tammy R. [Department of Pharmacology, Toxicology and Neuroscience, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA 71103 (United States)], E-mail: tdugas@lsuhsc.edu

2007-10-01

97

Meson production in proton-proton scattering within an extended linear sigma model  

E-print Network

We study the production of non-strange mesons in proton-proton scattering reactions within an effective model of mesons and baryons with global chiral symmetry. The model includes the nucleon ($N$) and its chiral partner ($N^{\\ast}$) and their couplings to the $N_{f}=2$ multiplets of (pseudo-)scalar and (axial-)vector mesons. Results for the production of $\\omega$ and $\\eta$ mesons are presented.

Khaled Teilab; Francesco Giacosa; Dirk H. Rischke

2014-06-13

98

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

E-print Network

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

Henderson, Cara Aletha Everett

2012-06-07

99

Imaging the proton via hard exclusive production in diffractive pp scattering  

SciTech Connect

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

Charles Hyde; Leonid Frankfurt; Mark Strikman; Christian Weiss

2007-05-21

100

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

PubMed

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 400mV 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

Pérez, Wanda I; Soto, Yarelys; Ortíz, Carmen; Matta, Jaime; Meléndez, Enrique

2015-02-01

101

Orally absorbed reactive glycation products (glycotoxins): An environmental risk factor in diabetic?nephropathy  

PubMed Central

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 (?10% of ingested AGE) correlated directly with severity of KD; renal excretion of dietary AGE, although normally incomplete (only ?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

Koschinsky, Theodore; He, Ci-Jiang; Mitsuhashi, Tomoko; Bucala, Richard; Liu, Cecilia; Buenting, Christina; Heitmann, Kirsten; Vlassara, Helen

1997-01-01

102

Simvastatin Inhibits C-Reactive Protein-Induced Pro-Inflammatory Changes in Endothelial Cells by Decreasing Mevalonate Pathway Products  

Microsoft Academic Search

Objectives: The effects of HMG-CoA reductase inhibitors on C-reactive protein (CRP)-induced pro-inflammatory changes in endothelial cells remain unclear. We tested the hypothesis that simvastatin inhibited CRP-induced pro-inflammatory changes in endothelial cells by decreasing mevalonate pathway products. Methods: Human umbilical vein endothelial cells were incubated with CRP and measurement of CD32, nuclear factor ?B (NF-?B) activation, vascular cell adhesion molecule-1 expression

Yao-Jen Liang; Kou-Gi Shyu; Bao-Wie Wang; Ling-Ping Lai

2008-01-01

103

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

Microsoft Academic Search

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

Arleta Malecka; Aneta Piechalak; Barbara Tomaszewska

2009-01-01

104

Endothelial Nitric Oxide Synthase Reduces Crescentic and Necrotic Glomerular Lesions, Reactive Oxygen Production, and MCP1 Production in Murine Lupus Nephritis  

PubMed Central

Systemic lupus erythematosus, in both animal models and in humans, is characterized by autoantibody production followed by immune complex deposition in target tissues. Ensuing target organ damage is modulated by reactive intermediates, including reactive nitrogen and oxygen species, through as of now incompletely understood mechanisms. Endothelial nitric oxide synthase is known to impact vascular reactivity; however its impact on reactive intermediate production and inflammatory renal disease is less well defined. In this study, we assessed the impact of endothelial nitric oxide synthase (eNOS) on disease in lupus prone MRL/lpr mice. Mice lacking eNOS developed earlier more severe disease with decreased survival. eNOS deficient mice died sooner and developed significantly more glomerular crescents, necrosis, inflammatory infiltrates and vasculitis, indicating a role for eNOS in modulating these renal lesions. Immune complex deposition was similar between groups, indicating the impact of eNOS is distal to antibody/complement glomerular deposition. Urinary nitric oxide production was decreased in the eNOS deficient mice, while proteinuria was increased. Urinary monocyte chemotactic protein-1 was also increased in the knockout mice. CD4+ T cells from MRL/lpr mice demonstrated mitochondrial hyperpolarization, increased nitric oxide and superoxide production and increased calcium flux compared to B6 control mice. Deficiency of eNOS resulted in decreased nitric oxide and mitochondrial calcium levels but had no effect on mitochondrial hyperpolarization. Renal cortices from MRL/lpr mice that are eNOS deficient demonstrated increased superoxide production, which was blocked by both nitric oxide synthase and NADPH oxidase inhibitors. These studies thus demonstrate a key role for eNOS in modulating renal disease in lupus prone MRL/lpr mice. The impact appears to be mediated by effects on superoxide production in the kidney, impacting downstream mediators such as monocyte chemotactic protein-1. These results suggest that modulation of eNOS may be a novel therapeutic approach to treating lupus nephritis. PMID:23741359

Gilkeson, Gary S.; Mashmoushi, Ahmad K.; Ruiz, Phillip; Caza, Tiffany N.; Perl, Andras; Oates, Jim C.

2013-01-01

105

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

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

Eyles, C J; Leibscher, M

2013-09-14

106

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

107

Jet production in high Q 2 deep-inelastic ep scattering at HERA  

Microsoft Academic Search

Two-jet production in deep-inelastic electron-proton scattering has been studied for 160< Q 2<1280 GeV2, 0.01< x<0.1 and 0.04< y<0.95 with the ZEUS detector at HERA. The kinematic properties of the jets and the jet production rates are presented. The partonic scaling variables of the two-jet system and the rate of two-jet production are compared to perturbative next-to-leading order QCD calculations.

M. Derrick; D. Krakauer; S. Magill; D. Mikunas; B. Musgrave; J. Repond; R. Stanek; R. L. Talaga; H. Zhang; R. Avad; G. Bari; M. Basile; L. Bellagamba; D. Boscherini; A. Bruni; G. Bruni; P. Bruni; G. Cara Romeo; G. Castellini; M. Chiarini; L. Cifarelli; F. Cindolo; A. Contin; M. Corradi; I. Gialas; P. Giusti; G. Iacobucci; G. Laurenti; G. Levi; A. Margotti; T. Massam; R. Nania; C. Nemoz; E. Palmonari; A. Polini; G. Sartorelli; R. Timellini; Y. Zamora Garcia; A. Zichichi; A. Bargende; J. Crittenden; K. Desch; B. Diekmann; T. Doeker; M. Eckert; L. Feld; A. Frey; M. Geerts; G. Geitz; M. Grothe; T. Haas; H. Hartmann; D. Haun; K. Heinloth; E. Hilger; H.-P. Jakob; U. F. Katz; S. M. Mari; A. Mass; S. Mengel; J. Mollen; E. Paul; Ch. Rembser; R. Schattevoy; D. Schramm; J. Stamm; R. Wedemeyer; S. Campbell-Robson; A. Cassidy; N. Dyce; B. Foster; S. George; R. Gilmore; G. P. Heath; H. F. Heath; T. J. Llewellyn; C. J. S. Morgado; D. J. P. Norman; J. A. O'Mara; R. I. Tapper; S. S. Wilson; R. Yoshida; R. R. Rau; M. Arneodo; L. Iannotti; M. Schioppa; G. Susinno; A. Bernstein; A. Caldwell; J. A. Parsons; S. Ritz; F. Sciulli; P. B. Straub; L. Wai; S. Yang; Q. Zhu; P. Borzemski; J. Chwastowski; A. Eskreys; K. Piotrzkowski; M. Zachara; L. Zawiejski; L. Adamczyk; B. Bednarek; K. Eskreys; K. Jelen; D. Kisielewska; T. Kowalski; E. Rulikowska-Zarebska; L. Suszycki; J. Zajac; A. Kotanski; M. Przybycien; I. A. T. Bauerdick; U. Behrens; H. Beier; J. K. Bienlein; C. Coldewey; O. Deppe; K. Desler; G. Drews; M. Flasinski; D. J. Gilkinson; C. Glasman; P. Göttlicher; J. Große-Knetter; B. Gutjahr; W. Hain; D. Hasell; H. Heßling; H. Hultschig; Y. Iga; P. Joos; M. Kasemann; R. Klanner; W. Koch; L. Köpke; U. Kötz; H. Kowalski; J. Labs; A. Ladage; B. Löhr; M. Löwe; D. Lüke; O. Manczak; J. S. T. Ng; S. Nickel; D. Notz; K. Ohrenberg; M. Roco; M. Rohde; J. Roldán; U. Schneekloth; W. Schulz; F. Selonke; E. Stiliaris; B. Surrow; T. Voß; D. Westphal; G. Wolf; C. Youngman; J. F. Zhou; H. J. Grabosch; A. Kharchilava; A. Leich; M. Mattingly; A. Meyer; S. Schlenstedt; N. Wulff; G. Barbagli; P. Pelfer; G. Anzivino; G. Maccarrone; S. de Pasquale; L. Votano; A. Bamberger; S. Eisenhardt; A. Freidhof; S. Söldner-Rembold; J. Schroeder; T. Trefzger; N. H. Brook; P. J. Bussey; A. T. Doyle; I. Fleck; D. H. Saxon; M. L. Utley; A. S. Wilson; A. Dannemann; U. Holm; D. Horstmann; T. Neumann; R. Sinkus; K. Wick; E. Badura; B. D. Burow; L. Hagge; E. Lohrmann; J. Mainusch; J. Milewski; M. Nakahata; N. Pavel; G. Poelz; W. Schott; F. Zetsche; T. C. Bacon; I. Butterworth; E. Gallo; V. L. Harris; B. Y. H. Hung; K. R. Long; D. B. Miller; P. P. O. Morawitz; A. Prinias; J. K. Sedgbeer; A. F. Whitfield; U. Mallik; E. McCliment; M. Z. Wang; S. M. Wang; J. T. Wu; Y. Zhang; P. Cloth; D. Filges; S. H. An; S. M. Hong; S. W. Nam; S. K. Park; M. H. Suh; S. H. Yon; R. Imlay; S. Kartik; H.-J. Kim; R. R. McNeil; W. Metcalf; V. K. Nadendla; F. Barreiro; G. Cases; R. Graciani; J. M. Hernández; L. Hervás; L. Labarga; J. Del Peso; J. Puga; J. Terron; J. F. de Trocóniz; G. R. Smith; F. Corriveau; D. S. Hanna; J. Hartmann; L. W. Hung; J. N. Lim; C. G. Matthews; P. M. Patel; L. E. Sinclair; D. G. Stairs; M. St. Laurent; R. Ullmann; G. Zacek; V. Bashkirov; B. A. Dolgoshein; A. Stifutkin; G. L. Bashindzhagyan; P. F. Ermolov; L. K. Gladilin; Y. A. Golubkov; V. D. Kobrin; V. A. Kuzmin; A. S. Proskuryakov; A. A. Savin; L. M. Shcheglova; A. N. Solomin; N. P. Zotov; M. Botje; F. Chlebana; A. Dake; J. Engelen; M. de Kamps; P. Kooijman; A. Kruse; H. Tiecke; W. Verkerke; M. Vreeswijk; L. Wiggers; E. de Wolf; R. van Woudenberg; D. Acosta; B. Bylsma; L. S. Durkin; K. Honscheid; C. Li; T. Y. Ling; K. W. McLean; W. N. Murray; I. H. Park; T. A. Romanowski; R. Seidlein; D. S. Bailey; G. A. Blair; A. Byrne; R. J. Cashmore; A. M. Cooper-Sarkar; D. Daniels; R. C. E. Devenish; N. Harnew; M. Lancaster; P. E. Luffman; L. Lindemann; J. D. McFall; C. Nath; V. A. Noyes; A. Quadt; H. Uijterwaal; R. Walczak; F. F. Wilson; T. Yip; G. Abbiendi; A. Bertolin; R. Brugnera; R. Carlin; F. Dal Corso; M. de Giorgi; U. Dosselli; S. Limentani; M. Morandin; M. Posocco; L. Stanco; R. Stroili; C. Voci; J. Bulmahn; J. M. Butterworth; R. G. Feild; B. Y. Oh; J. J. Whitmore; G. D'Agostini; G. Marini; A. Nigro; E. Tassi; J. C. Hart; N. A. McCubbin; K. Prytz; T. P. Shah; T. L. Short; L. Barberis; N. Cartiglia; T. Dubbs; C. Heusch; M. van Hook; B. Hubbard; W. Lockman; J. T. Rahn; H. F.-W. Sadrozinski; A. Seiden; J. Biltzinger; R. J. Seifert; A. H. Walenta; G. Zech; H. Abramowicz; G. Briskin; S. Dagan; A. Levy; T. Hasegawa; M. Hazumi; T. Ishii; M. Kuze; S. Mine; Y. Nagasawa; M. Nakao; I. Suzuki; K. Tokushuku; S. Yamada; Y. Yamazaki; M. Chiba; R. Hamatsu; T. Hirose; K. Homma; S. Kitamura; Y. Nakamitsu; K. Yamauchi; R. Cirio; M. Costa; M. I. Ferrero; L. Lamberti; S. Maselli; C. Peroni; R. Sacchi

1995-01-01

108

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

E-print Network

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

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

2010-05-06

109

Dietary glycotoxins: inhibition of reactive products by aminoguanidine facilitates renal clearance and reduces tissue sequestration.  

PubMed

Evidence indicates that the metabolic turnover of food-derived reactive orally absorbed advanced glycation end products (AGEs) or glycotoxins (GTs) is delayed, possibly contributing to the tissue damage induced by endogenous AGEs, especially in patients with diabetes and kidney disease. The aim of this study was to explore whether pharmacologic inhibition of dietary AGE bioreactivity by aminoguanidine (AG) can improve turnover and renal excretion of these substances. Normal Sprague-Dawley rats were fed single-labeled [14C]AGE-ovalbumin, double-labeled [14C-125I]AGE-ovalbumin, or control 125I-labeled ovalbumin diet plus free [14C]glucose, with or without AG (0.2% in water). [14C]AGE- and 125I-labeled peptide-associated radioactivity (RA) were compared with AGE immunoreactivity (by enzyme-linked immunosorbent assay) in tissues, serum, and 72-h urine samples. The effect of AG on dietary AGE bioreactivity was assessed by monitoring the inhibition of covalent complex formation between fibronectin (FN) peptide fragments and serum components, after a meal of labeled dietary AGE with or without AG. The radiolabeled AGE diet produced serum absorption and urinary excretion peaks kinetically distinct from those of free [14C]glucose or [125I]ovalbumin. Some 26% of the orally absorbed AGE-ovalbumin was excreted in the urine, whereas after AG treatment, urinary excre-tion of dietary AGEs increased markedly (to >50% of absorbed). More than 60% of tissue-bound RA was found covalently deposited in kidneys and liver, whereas after treatment with AG, tissue AGE deposits were reduced to <15% of the amount found in untreated AGE-fed controls. Sera enriched for dietary GTs formed covalently linked complexes with FN, a process completely inhibitable by AG cotreatment. Amelioration of dietary GT bioreactivity by AG improves renal elimination and prevents tissue deposition of food GTs. This may afford a novel and potentially protective use of AG against excessive tissue AGE toxicity in diabetic patients with renal disease. PMID:10342821

He, C; Sabol, J; Mitsuhashi, T; Vlassara, H

1999-06-01

110

Functional equations for one-loop master integrals for heavy-quark production and Bhabha scattering  

E-print Network

The method for obtaining functional equations, recently proposed by one of the authors, is applied to one-loop box integrals needed in calculations of radiative corrections to heavy-quark production and Bhabha scattering. We present relationships between these integrals with different arguments and box integrals with all propagators being massless. It turns out that functional equations are rather useful for finding imaginary parts and performing analytic continuations of Feynman integrals. For the box master integral needed in Bhabha scattering, a new representation in terms of hypergeometric functions admitting one-fold integral representation is derived. The hypergeometric representation of a master integral for heavy-quark production follows from the functional equation.

Bernd A. Kniehl; Oleg V. Tarasov

2009-04-23

111

Moderators of cardiovascular reactivity to speech: discourse production and group variations in blood pressure and pulse rate.  

PubMed

To explain why speech produces cardiovascular reactivity, an experiment utilized speech tasks varying in self-disclosure and cognitive preparation and measured the blood pressure and pulse rate of African-American and Caucasian, men and women subjects. One hundred and fifty-six college students with a median age of 21 volunteered to participate. The extemporaneous speech task produced lower systolic blood pressure than the prepared speech task. Self-disclosive speech resulted in lower diastolic blood pressure than non-disclosive speech. Females showed higher pulse rate and men exhibited greater diastolic blood pressure while speaking. Results supported previous research suggesting that women are myocardiacal hyperreactors, while men are vascular hypperreactors and suggest that production processes moderate cardiovascular reactivity to speech. PMID:9666379

Tardy, C H; Allen, M T

1998-08-01

112

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...

113

Exclusive ? 0 production in deep inelastic electron-proton scattering at HERA  

Microsoft Academic Search

The exclusive production of ?0 mesons in deep inelastic electron-proton scattering has been studied using the ZEUS detector. Cross sections have been measured in the range 7 < Q2 < 25 GeV2 for ??p centre of mass (c.m.) energies 40 to 130 GeV. The ??p ? ?0p cross section exhibits a Q?(4.2±0.8?0.5+1.4) dependence and both longitudinally and transversely polarised ?0's

S. Bhadra; M. L. Cardy; C.-P. Fagerstroem; W. R. Frisken; K. M. Furutani; M. Khakzad; W. B. Schmidke; R. L. Talaga; H. Zhang; R. Ayad; G. Bari; M. Basile; L. Bellagamba; D. Boscherini; A. Bruni; G. Bruni; P. Bruni; G. Cara Romeo; G. Castellini; M. Chiarini; Luisa Cifarelli; F. Cindolo; A. Contin; M. Corradi; I. Gialas; P. Giusti; G. Iacobucci; G. Laurenti; G. Levi; A. Margotti; Thomas Massam; R. Nania; C. Nemoz; F. Palmonari; A. Polini; G. Sartorelli; R. Timellini; Y. Zamora Garcia; Antonino Zichichi; A. Bargende; James Arthur Crittenden; Klaus Desch; B. Diekmann; T. Doeker; M. Eckert; L. Feld; A. Frey; M. Geerts; M. Grothe; H. Hartmann; K. Heinloth; E. Hilger; H.-P. Jakob; U. F. Katz; S. M. Mari; S. Mengel; J. Mollen; E. Paul; M. Pfeiffer; Ch. Rembser; D. Schramm; J. Stamm; R. Wedemeyer; S. Campbell-Robson; A. Cassidy; N. Dyce; B. Foster; S. George; R. Gilmore; G. P. Heath; H. F. Heath; T. J. Llewellyn; C. J. S. Morgado; D. J. P. Norman; J. A. O'Mara; R. J. Tapper; S. S. Wilson; R. Yoshida; R. R. Rau; M. Arneodo; M. Capua; A. Garfagnini; L. Iannotti; M. Schioppa; G. Susinno; A M Bernstein; A. Caldwell; N. Cartiglia; J. A. Parsons; S. Ritz; F. Sciulli; P. B. Straub; L. Wai; S. Yang; Q. Zhu; P. Borzemski; J. Chwastowski; Andrzej Eskreys; K. Piotrzkowski; M. Zachara; L. Zawiejski; L. Adamczyk; B. Bednarek; K. Jelen; D. Kisielewska; T. Kowalski; E. Rulikowska-Zarebska; L. Suszycki; J. Zajac; Andrzej Kotanski; M B Przybycien; L. A. T. Bauerdick; U. Behrens; H. Beier; J. K. Bienlein; C. Coldewey; O. Deppe; K. Desler; G. Drews; M. Flasinski; D. J. Gilkinson; C. Glasman; P. Göttlicher; J Grosse-Knetter; B. Gutjahr; T. Haas; W. Hain; D. Hasell; H Hessling; Y. Iga; K. Johnson; P. Joos; M. Kasemann; Robert Klanner; W. Koch; L. Köpke; U. Kötz; H. Kowalski; J. Labs; A. Ladage; B. Löhr; M Loewe; D. Lüke; J. Mainusch; O. Manczak; T. Monteiro; J. S. T. Ng; S. Nickel; D. Notz; K. Ohrenberg; M T Roco; M. Rohde; J. Roldán; U. Schneekloth; W. Schulz; F. Selonke; E. Stiliaris; B. Surrow; T Voss; D. Westphal; G. Wolf; C. Youngman; W. Zeuner; J. F. Zhou; H. J. Grabosch; A I Kharchilava; A. Leich; M. C. K. Mattingly; A. Meyer; S. Schlenstedt; N. Wulff; G. Barbagli; P G Pelfer; Giuseppina Anzivino; G D Maccarrone; S. de Pasquale; L. Votano; Andreas Bamberger; S. Eisenhardt; A. Freidhof; S. Söldner-Rembold; J. Schroeder; T M Trefzger; N. H. Brook; Peter J Bussey; A. T. Doyle; J. I. Fleck; D. H. Saxon; M. L. Utley; A. S. Wilson; A. Dannemann; U. Holm; D. Horstmann; T. Neumann; R. Sinkus; K. Wick; E. Badura; B. D. Burow; L. Hagge; E. Lohrmann; J. Milewski; M. Nakahata; N. Pavel; G. Poelz; W. Schott; F. Zetsche; Trevor C Bacon; N. Bruemmer; Ian Butterworth; E. Gallo; V. L. Harris; B. H. Y. Hung; K. R. Long; D. B. Miller; P. P. O. Morawitz; A. Prinias; J. K. Sedgbeer; A. F. Whitfield; U. Mallik; E. McCliment; M. Z. Wang; S. M. Wang; J. T. Wu; P. Cloth; D. Filges; S. H. An; S. M. Hong; S. W. Nam; S. K. Park; M. H. Suh; S. H. Yon; R. Imlay; S. Kartik; H.-J. Kim; R. R. McNeil; W. Metcalf; V. K. Nadendla; F. Barreiro; G. Cases; J. P. Fernandez; R. Graciani; J. M. Hernández; L. Hervás; L. Labarga; M. Martinez; J. del Peso; J. Puga; J. Terron; J. F. de Trocóniz; G. R. Smith; F. Corriveau; D. S. Hanna; J. Hartmann; L. W. Hung; J. N. Lim; C. G. Matthews; P. M. Patel; L. E. Sinclair; D. G. Stairs; M. St. Laurent; R T Ullmann; G. Zacek; V. Bashkirov; B. A. Dolgoshein; A. Stifutkin; G. L. Bashindzhagyan; P. F. Ermolov; L. K. Gladilin; Yu. A. Golubkov; V. D. Kobrin; I. A. Korzhavina; V. A. Kuzmin; O. Yu. Lukina; A. S. Proskuryakov; A. A. Savin; L. M. Shcheglova; A. N. Solomin; N. P. Zotov; M. Botje; F S Chlebana; A P Dake; J. Engelen; M. de Kamps; P M Kooijman; A. Kruse; H G Tiecke; W. Verkerke; M. Vreeswijk; L. Wiggers; E. de Wolf; R. van Woudenberg; D. Acosta; B G Bylsma; L. S. Durkin; K. Honscheid; Li Chuan; T. Y. Ling; K. W. McLean; W. N. Murray; I. H. Park; T. A. Romanowski; R. Seidlein; D. S. Bailey; A. Byrne; R. J. Cashmore; A. M. Cooper-Sarkar; R. C. E. Devenish; N. Harnew; M. Lancaster; L. Lindemann; J. D. McFall; C. Nath; V. A. Noyes; A. Quadt; J. R. Tickner; H. Uijterwaal; R. Walczak; D. S. Waters; F. F. Wilson; T. Yip; G. Abbiendi; A. Bertolin; R. Brugnera; R. Carlin; F. dal Corso; M. de Giorgi; U. Dosselli; S. Limentani; M. Morandin; M. Posocco; L. Stanco; R. Stroili; C. Voci; J. Bulmahn; J. M. Butterworth; R. G. Feild; B. Y. Oh; J. J. Whitmore; G. D'Agostini; G. Marini; A. Nigro; E. Tassi; J. C. Hart; N. A. McCubbin; K. Prytz; T. P. Shah; T. L. Short; E. Barberis; T. Dubbs; C. Heusch; M. van Hook; W. Lockman; J. T. Rahn; H. F.-W. Sadrozinski; A. Seiden; D. C. Williams; J. Biltzinger; R. J. Seifert; O. Schwarzer; A. H. Walenta; G. Zech; H. Abramowicz; G. Briskin; S. Dagan; A. Levy; T. Hasegawa; M. Hazumi; T. Ishii; M. Kuze; S. Mine; Y. Nagasawa; M. Nakao; I. Suzuki

1995-01-01

114

Observation of jet production in deep inelastic scattering with a large rapidity gap at HERA  

Microsoft Academic Search

Events with a large rapidity gap in deep inelastic scattering with Q2 >= 10 GeV2 have been studied in the ZEUS detector. The properties of these events with W > 140 GeV are consistent with a leading twist diffractive production mechanism. In the laboratory frame, with ETjet >= 4 GeV, 15% of the events are of the 1-jet type with

M. Derrick; D. Krakauer; S. Magill; B. Musgrave; J. Repond; J. Schlereth; R. Stanek; R. L. Talaga; J. Thron; F. Arzarello; R. Ayad; G. Bari; M. Basile; L. Bellagamba; D. Boscherini; A. Bruni; G. Bruni; P. Bruni; G. Cara Romeo; G. Castellini; M. Chiarini; L. Cifarelli; F. Cindolo; F. Ciralli; A. Contin; S. D'Auria; C. del Papa; F. Frasconi; P. Giusti; G. Iacobucci; G. Laurenti; G. Levi; G. Maccarrone; A. Margotti; T. Massam; R. Nania; C. Nemoz; F. Palmonari; G. Sartorelli; R. Timellini; Y. Zamora Garcia; A. Zichichi; A. Bargende; J. Crittenden; K. Desch; B. Diekmann; T. Doeker; L. Feld; A. Frey; M. Geerts; G. Geitz; H. Hartmann; D. Haun; K. Heinloth; E. Hilger; H.-P. Jakob; U. F. Katz; S. Kramarczyk; A. Mass; S. Mengel; J. Mollen; E. Paul; Ch. Rembser; R. Schattevoy; J.-L. Schneider; D. Schramm; J. Stamm; R. Wedemeyer; S. Campbell-Robson; A. Cassidy; N. Dyce; B. Foster; S. George; R. Gilmore; G. P. Heath; H. F. Heath; T. J. Llewellyn; C. J. S. Morgado; D. J. P. Norman; J. A. O'Mara; R. J. Tapper; S. S. Wilson; R. Yoshida; R. R. Rau; M. Arneodo; M. Schioppa; G. Susinno; A. Bernstein; A. Caldwell; I. Gialas; J. A. Parsons; S. Ritz; F. Sciulli; P. B. Straub; L. Wai; S. Yang; P. Borzemski; J. Chwastowski; A. Eskreys; K. Piotrzkowski; M. Zachara; L. Zawiejski; L. Adamczyk; B. Bednarek; K. Eskreys; K. Jelen; D. Kisielewska; T. Kowalski; E. Rulikowska-Zarebska; L. Suszycki; J. Zajc; T. Kedzierski; A. Kotanski; M. Przybycien; L. A. T. Bauerdick; U. Behrens; J. K. Bienlein; S. Böttcher; C. Coldewey; G. Drews; M. Flasinski; I. Fleck; D. J. Gilkinson; P. Göttlicher; B. Gutjahr; T. Haas; L. Hagge; W. Hain; D. Hassell; H. Heßling; H. Hultschig; P. Joos; M. Kasemann; R. Klanner; W. Koch; L. Köpke; U. Kötz; H. Kowalski; W. Kröger; J. Krüger; J. Labs; A. Ladage; B. Löhr; M. Löwe; D. Lüke; J. Mainusch; O. Manczak; J. S. T. Ng; S. Nickel; D. Notz; K. Ohrenberg; M. Rohde; J. Roldán; U. Schneekloth; J. Schroeder; W. Schulz; F. Selonke; E. Stiliaris; T. Tsurugai; W. Vogel; D. Westphal; G. Wolf; C. Youngman; H. J. Grabosch; J. Leich; A. Meyer; C. Rethfeldt; S. Schlenstedt; G. Barbagli; M. Nuti; P. Pelfer; G. Anzivino; S. de Pasquale; S. Qian; L. Votano; A. Bamberger; A. Freidhof; T. Poser; S. Söldner-Rembold; G. Theisen; T. Trefzger; N. H. Brook; P. J. Bussey; A. T. Doyle; J. R. Forbes; V. A. Jamieson; C. Raine; D. H. Saxon; M. Stavrianakou; A. S. Wilson; A. Dannemann; U. Holm; D. Horstmann; H. Kammerlocher; B. Krebs; T. Neumann; R. Sinkus; K. Wick; E. Badura; B. D. Burow; A. Fürtjes; E. Lohrmann; J. Milewski; M. Nakahata; N. Pavel; G. Poelz; W. Schott; J. Terron; F. Zetsche; T. C. Bacon; R. Beuselinck; I. Butterworth; E. Gallo; V. L. Harris; K. R. Long; D. B. Miller; P. Morawitz; A. Prinias; J. K. Sedgbeer; A. Vorvolakos; A. Whitfield; T. Bienz; H. Kreutzmann; U. Mallik; E. McCliment; M. Roco; M. Z. Wang; P. Cloth; D. Filges; S. H. An; S. M. Hong; C. O. Kim; T. Y. Kim; S. W. Nam; S. K. Park; M. H. Suh; S. H. Yon; R. Imlay; S. Kartik; H.-J. Kim; R. R. McNeil; W. Metcalf; V. K. Nadendla; F. Barreiro; G. Cases; R. Graciani; J. M. Hernández; L. Hervás; L. Labarga; J. del Peso; J. Puga; J. F. de Trocóniz; F. Ikraiam; J. K. Mayer; G. R. Smith; F. Corriveau; D. S. Hanna; J. Hartmann; L. W. Hung; J. N. Lim; C. G. Matthews; J. W. Mitchell; P. M. Patel; L. E. Sinclair; D. G. Stairs; M. St. Laurent; R. Ullmann; V. Bashkirov; B. A. Dolgoshein; A. Stifutkin; G. L. Bashindzhagyan; P. F. Ermolov; L. K. Gladilin; Y. A. Golubkov; V. D. Kobrin; V. A. Kuzmin; E. N. Kuznetsov; A. A. Savin; A. N. Solomin; A. G. Voronin; N. P. Zotov; S. Bentvelsen; M. Botje; F. Chlebana; A. Dake; J. Engelen; P. de Jong; M. de Kamps; P. Kooijman; A. Kruse; V. O'dell; A. Tenner; H. Tiecke; W. Verkerke; M. Vreeswijk; L. Wiggers; E. de Wolf; R. van Woudenberg; D. Acosta; B. Bylsma; L. S. Durkin; K. Honscheid; C. Li; T. Y. Ling; K. W. McLean; W. N. Murray; I. H. Park; T. A. Romanowski; R. Seidlein; D. S. Bailey; G. A. Blair; A. Byrne; R. J. Cashmore; A. M. Cooper-Sarkar; D. Daniels; R. C. E. Devenish; N. Harnew; M. Lancaster; P. E. Luffman; J. McFall; C. Nath; A. Quadt; H. Uijterwaal; R. Walczak; F. F. Wilson; T. Yip; G. Abbiendi; A. Bertolin; R. Brugnera; R. Carlin; F. dal Corso; M. de Giorgi; U. Dosselli; F. Gasparini; S. Limentani; M. Morandin; M. Posocco; L. Stanco; R. Stroili; C. Voci; J. Bulmahn; J. M. Butterworth; R. G. Feild; B. Y. Oh; J. J. Whitmore; G. D'Agostini; M. Guida; M. Iori; S. M. Mari; G. Marini; M. Mattioli; A. Nigro; J. C. Hart; N. A. McCubbin; K. Prytz; T. P. Shah; T. L. Short; E. Barberis; N. Cartiglia; C. Heusch; M. van Hook; B. Hubbard; W. Lockman; H. F.-W. Sadrozinski; A. Seiden; D. Zer-Zion; J. Biltzinger; R. J. Seifert; A. H. Walenta; G. Zech; H. Abramowicz; S. Dagan; A. Levy; T. Hasegawa; M. Hazumi; T. Ishii; M. Kuze; S. Mine; Y. Nagasawa; T. Nagira; M. Nakao; I. Suzuki; K. Tokushuku

1994-01-01

115

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

Microsoft Academic Search

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

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

2006-01-01

116

Spatiotemporal Patterning of Reactive Oxygen Production and Ca2+ Wave Propagation in Fucus Rhizoid Cells  

Microsoft Academic Search

Both Ca 2 ? and reactive oxygen species (ROS) play critical signaling roles in plant responses to biotic and abiotic stress. However, the positioning of Ca 2 ? and ROS (in particular H 2 O 2 ) after a stress stimulus and their subcellular interactions are poorly understood. Moreover, although information can be encoded in different patterns of cellular Ca

Susana M. Coelho; Alison R. Taylor; Keith P. Ryan; Isabel Sousa-Pinto; Murray T. Brown; Colin Brownlee; Drake Circus

2002-01-01

117

Jet production in highQ 2 deep-inelastic ep scattering at HERA  

Microsoft Academic Search

Two-jet production in deep-inelastic electron-proton scattering has been\\u000astudied for $160production are compared to perturbative\\u000anext-to-leading order QCD calculations.

M. Derrick; D. Krakauer; S. Magill; D. Mikunas; B. Musgrave; J. Repond; R. Stanek; R. L. Talaga; H. Zhang; R. Avad; G. Bari; M. Basile; L. Bellagamba; D. Boscherini; A. Bruni; G. Bruni; P. Bruni; G. Cara Romeo; G. Castellini; M. Chiarini; L. Cifarelli; F. Cindolo; A. Contin; M. Corradi; I. Gialas; P. Giusti; G. Iacobucci; G. Laurenti; G. Levi; A. Margotti; T. Massam; R. Nania; C. Nemoz; E. Palmonari; A. Polini; G. Sartorelli; R. Timellini; Y. Zamora Garcia; A. Zichichi; A. Bargende; J. Crittenden; K. Desch; B. Diekmann; T. Doeker; M. Eckert; L. Feld; A. Frey; M. Geerts; G. Geitz; M. Grothe; T. Haas; H. Hartmann; D. Haun; K. Heinloth; E. Hilger; H.-P. Jakob; U. F. Katz; S. M. Mari; A. Mass; S. Mengel; J. Mollen; E. Paul; Ch. Rembser; R. Schattevoy; D. Schramm; J. Stamm; R. Wedemeyer; S. Campbell-Robson; A. Cassidy; N. Dyce; B. Foster; S. George; R. Gilmore; G. P. Heath; H. F. Heath; T. J. Llewellyn; C. J. S. Morgado; D. J. P. Norman; J. A. O'Mara; R. I. Tapper; S. S. Wilson; R. Yoshida; R. R. Rau; M. Arneodo; L. Iannotti; M. Schioppa; G. Susinno; A. Bernstein; A. Caldwell; J. A. Parsons; S. Ritz; F. Sciulli; P. B. Straub; L. Wai; S. Yang; Q. Zhu; P. Borzemski; J. Chwastowski; A. Eskreys; K. Piotrzkowski; M. Zachara; L. Zawiejski; L. Adamczyk; B. Bednarek; K. Eskreys; K. Jele?; D. Kisielewska; T. Kowalski; E. Rulikowska-Zar?bska; L. Suszycki; J. Zaj?c; A. Kota?ski; M. Przybycie?; I. A. T. Bauerdick; U. Behrens; H. Beier; J. K. Bienlein; C. Coldewey; O. Deppe; K. Desler; G. Drews; M. Flasi?ski; D. J. Gilkinson; C. Glasman; P. Göttlicher; J. Große-Knetter; B. Gutjahr; W. Hain; D. Hasell; H. Heßling; H. Hultschig; Y. Iga; P. Joos; M. Kasemann; R. Klanner; W. Koch; L. Köpke; U. Kötz; H. Kowalski; J. Labs; A. Ladage; B. Löhr; M. Löwe; D. Lüke; O. Ma?czak; J. S. T. Ng; S. Nickel; D. Notz; K. Ohrenberg; M. Roco; M. Rohde; J. Roldán; U. Schneekloth; W. Schulz; F. Selonke; E. Stiliaris; B. Surrow; T. Voß; D. Westphal; G. Wolf; C. Youngman; J. F. Zhou; H. J. Grabosch; A. Kharchilava; A. Leich; M. Mattingly; A. Meyer; S. Schlenstedt; N. Wulff; G. Barbagli; P. Pelfer; G. Anzivino; G. Maccarrone; S. Pasquale; L. Votano; A. Bamberger; S. Eisenhardt; A. Freidhof; S. Söldner-Rembold; J. Schroeder; T. Trefzger; N. H. Brook; P. J. Bussey; A. T. Doyle; I. Fleck; D. H. Saxon; M. L. Utley; A. S. Wilson; A. Dannemann; U. Holm; D. Horstmann; T. Neumann; R. Sinkus; K. Wick; E. Badura; B. D. Burow; L. Hagge; E. Lohrmann; J. Mainusch; J. Milewski; M. Nakahata; N. Pavel; G. Poelz; W. Schott; F. Zetsche; T. C. Bacon; I. Butterworth; E. Gallo; V. L. Harris; B. Y. H. Hung; K. R. Long; D. B. Miller; P. P. O. Morawitz; A. Prinias; J. K. Sedgbeer; A. F. Whitfield; U. Mallik; E. McCliment; M. Z. Wang; S. M. Wang; J. T. Wu; Y. Zhang; P. Cloth; D. Filges; S. H. An; S. M. Hong; S. W. Nam; S. K. Park; M. H. Suh; S. H. Yon; R. Imlay; S. Kartik; H.-J. Kim; R. R. McNeil; W. Metcalf; V. K. Nadendla; F. Barreiro; G. Cases; R. Graciani; J. M. Hernández; L. Hervás; L. Labarga; J. Peso; J. Puga; J. Terron; J. F. Trocóniz; G. R. Smith; F. Corriveau; D. S. Hanna; J. Hartmann; L. W. Hung; J. N. Lim; C. G. Matthews; P. M. Patel; L. E. Sinclair; D. G. Stairs; M. St. Laurent; R. Ullmann; G. Zacek; V. Bashkirov; B. A. Dolgoshein; A. Stifutkin; G. L. Bashindzhagyan; P. F. Ermolov; L. K. Gladilin; Y. A. Golubkov; V. D. Kobrin; V. A. Kuzmin; A. S. Proskuryakov; A. A. Savin; L. M. Shcheglova; A. N. Solomin; N. P. Zotov; M. Botje; F. Chlebana; A. Dake; J. Engelen; M. Kamps; P. Kooijman; A. Kruse; H. Tiecke; W. Verkerke; M. Vreeswijk; L. Wiggers; E. Wolf; R. Woudenberg; D. Acosta; B. Bylsma; L. S. Durkin; K. Honscheid; C. Li; T. Y. Ling; K. W. McLean; W. N. Murray; I. H. Park; T. A. Romanowski; R. Seidlein; D. S. Bailey; G. A. Blair; A. Byrne; R. J. Cashmore; A. M. Cooper-Sarkar; D. Daniels; R. C. E. Devenish; N. Harnew; M. Lancaster; P. E. Luffman; L. Lindemann; J. D. McFall; C. Nath; V. A. Noyes; A. Quadt; H. Uijterwaal; R. Walczak; F. F. Wilson; T. Yip; G. Abbiendi; A. Bertolin; R. Brugnera; R. Carlin; F. Corso; M. Giorgi; U. Dosselli; S. Limentani; M. Morandin; M. Posocco; L. Stanco; R. Stroili; C. Voci; J. Bulmahn; J. M. Butterworth; R. G. Feild; B. Y. Oh; J. J. Whitmore; G. D'Agostini; G. Marini; A. Nigro; E. Tassi; J. C. Hart; N. A. McCubbin; K. Prytz; T. P. Shah; T. L. Short; L. Barberis; N. Cartiglia; T. Dubbs; C. Heusch; M. Hook; B. Hubbard; W. Lockman; J. T. Rahn; H. F.-W. Sadrozinski; A. Seiden; J. Biltzinger; R. J. Seifert; A. H. Walenta; G. Zech; H. Abramowicz; G. Briskin; S. Dagan; A. Levy; T. Hasegawa; M. Hazumi; T. Ishii; M. Kuze; S. Mine; Y. Nagasawa; M. Nakao; I. Suzuki; K. Tokushuku; S. Yamada; Y. Yamazaki; M. Chiba; R. Hamatsu; T. Hirose; K. Homma; S. Kitamura; Y. Nakamitsu; K. Yamauchi; R. Cirio; M. Costa; M. I. Ferrero; L. Lamberti; S. Maselli; C. Peroni; R. Sacchi; A. Solano; A. Staiano; M. Dardo

1995-01-01

118

Origin of cadmium-induced reactive oxygen species production: mitochondrial electron transfer versus plasma membrane NADPH oxidase.  

PubMed

* Cadmium (Cd(2+)) is an environmental pollutant that causes increased reactive oxygen species (ROS) production. To determine the site of ROS production, the effect of Cd(2+) on ROS production was studied in isolated soybean (Glycine max) plasma membranes, potato (Solanum tuberosum) tuber mitochondria and roots of intact seedlings of soybean or cucumber (Cucumis sativus). * The effects of Cd(2+) on the kinetics of superoxide (O2*-), hydrogen peroxide (H(2)O(2)) and hydroxyl radical ((*OH) generation were followed using absorption, fluorescence and spin-trapping electron paramagnetic resonance spectroscopy. * In isolated plasma membranes, Cd(2+) inhibited O2*- production. This inhibition was reversed by calcium (Ca(2+)) and magnesium (Mg(2+)). In isolated mitochondria, Cd(2+) increased and H(2)O(2) production. In intact roots, Cd(2+) stimulated H(2)O(2) production whereas it inhibited O2*- and (*)OH production in a Ca(2+)-reversible manner. * Cd(2+) can be used to distinguish between ROS originating from mitochondria and from the plasma membrane. This is achieved by measuring different ROS individually. The immediate (production in the mitochondrial electron transfer chain and inhibition of NADPH oxidase activity in the plasma membrane. PMID:18537884

Heyno, Eiri; Klose, Cornelia; Krieger-Liszkay, Anja

2008-01-01

119

Amplifying the manganese scavenging potential of Streptococcus zooepidemicus to reactive oxygen species during production of hyaluronic acid.  

PubMed

Streptococcus zooepidemicus (SZ) is an aerotolerant bacteria and its ability to survive under reactive oxidant challenge raises the question of the existence of a defense system. Thus growth, hyaluronic acid (HA) and hydrogen peroxide (H2O2) production by SZ in the presence of increasing concentration of Mn2+ were studied. The results suggested that the tested strain supported growth and HA production in cultures treated with 1 and 10 mM of Mn2+ regardless of H2O2 presence in the medium. This showed that SZ have acquired elaborate defense mechanisms to scavenge oxygen toxicity and thus protect cells from direct and indirect effect of this radical. In contrast, cells treated with 25 mM Mn2+ were sensitive, in which, the HA production was reduced considerably. Thus showing that the oxygen scavenger systems of the cells may be fully saturated at this concentration. PMID:15468818

Mashitah, M D; Masitah, H; Ramachandran, K B

2004-05-01

120

Reactive carburizing sintering—A novel production method for high quality chromium carbide–nickel cermets  

Microsoft Academic Search

Reactive carburizing sintering is a novel process where synthesis reaction of the carbide phase is combined with liquid phase sintering of the Cr3C2–Ni cermet. This recently developed method is compared with traditional cermet industry routine. Powder of chromium, nickel, and carbon black were milled in a high-energy ball mill (attritor) to nanocrystalline size and pressed to compacts. During the next

Jüri Pirso; Mart Viljus; Sergei Letunovits; Kristjan Juhani

2006-01-01

121

Indirect photochemistry in sunlit surface waters: photoinduced production of reactive transient species.  

PubMed

This paper gives an overview of the main reactive transient species that are produced in surface waters by sunlight illumination of photoactive molecules (photosensitizers), such as nitrate, nitrite, and chromophoric dissolved organic matter (CDOM). The main transients (?OH, CO3(-?) , (1)O2, and CDOM triplet states) are involved in the indirect phototransformation of a very wide range of persistent organic pollutants in surface waters. PMID:24888627

Vione, Davide; Minella, Marco; Maurino, Valter; Minero, Claudio

2014-08-18

122

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

SciTech Connect

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

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

2013-04-02

123

Benidipine, an anti-hypertensive drug, inhibits reactive oxygen species production in polymorphonuclear leukocytes and oxidative stress in salt-loaded stroke-prone spontaneously hypertensive rats.  

PubMed

Oxidative stress is associated with exacerbation of renal injuries in hypertension. In clinical studies benidipine hydrochloride (benidipine), a dihydropyridine calcium channel blocker with antioxidant activity, reduced oxidative stress. However, the mechanism of suppression of oxidative stress remains to be fully characterized. Reactive oxygen species production by polymorphonuclear leukocyte plays important pathological roles in hypertension. Therefore, we examined the effects of benidipine both on reactive oxygen species production of human polymorphonuclear leukocytes and oxidative stress of an animal model. Human peripheral polymorphonuclear leukocytes or polymorphonuclear leukocyte-like differentiated HL-60 cells were used to examine effects of benidipine (0.1-30 microM) on formyl-Met-Leu-Phe-induced reactive oxygen species production, calcium mobilization, NADPH oxidase activation and phosphorylation of protein kinase C substrates. High-salt (8% NaCl) loaded stroke-prone spontaneously hypertensive rats were treated with or without benidipine (1, 3, 10 mg/kg/day) for 2 weeks, and thiobarbituric acid reactive substances, a plasma oxidative stress marker, and renal expression of oxidative stress-induced genes were measured. Benidipine concentration-dependently suppressed formyl-Met-Leu-Phe-induced reactive oxygen species production in polymorphonuclear leukocytes more potently than other calcium channel blockers such as amlodipine, azelnidipine, nitrendipine and nifedipine. Benidipine partially inhibited all of intracellular Ca(2+) elevation, protein kinase C activation and NADPH oxidase activation. Salt loading in stroke-prone spontaneously hypertensive rats augmented plasma thiobarbituric acid reactive substances levels; renal dysfunction; and renal expression of transforming growth factor-beta, collagen I and collagen III mRNAs; which were attenuated by benidipine treatment. These results indicate that benidipine prevents the polymorphonuclear leukocyte-derived reactive oxygen species production, which is due at least in part to its antioxidant action and inhibition of Ca(2+)/protein kinase C/NADPH oxidase signaling. The attenuation of reactive oxygen species production might contribute to the drug's reduction of oxidative stress and renal injuries in hypertension. PMID:18048030

Matsubara, Masahiro; Akizuki, Osamu; Ikeda, Jun-ichi; Saeki, Koji; Yao, Kozo; Sasaki, Katsutoshi

2008-02-01

124

Measurement of D*+- meson production in ep scattering at low Q^2  

E-print Network

The production of D*+-(2010) mesons in ep scattering in the range of exchanged photon virtuality 0.05 D0 pi+ with D0 -> K- pi+ and corresponding antiparticle decay were used to identify D* mesons and the ZEUS beampipe calorimeter was used to identify the scattered electron. Differential D* cross sections as functions of Q^2, inelasticity, y, transverse momentum of the D* meson, p_T(D*), and pseudorapidity of the D* meson, eta(D*), have been measured in the kinematic region 0.02 < y < 0.85, 1.5 < p_T(D*) < 9.0 GeV and |eta(D*)| < 1.5. The measured differential cross sections are in agreement with two different NLO QCD calculations. The cross sections are also compared to previous ZEUS measurements in the photoproduction and DIS regimes.

ZEUS Collaboration; S. Chekanov

2007-04-10

125

Measurement of $D*{+-}$ meson production in ep scattering at low $Q^{2}$  

E-print Network

The production of D*+-(2010) mesons in ep scattering in the range of exchanged photon virtuality 0.05 D0 pi+ with D0 -> K- pi+ and corresponding antiparticle decay were used to identify D* mesons and the ZEUS beampipe calorimeter was used to identify the scattered electron. Differential D* cross sections as functions of Q^2, inelasticity, y, transverse momentum of the D* meson, p_T(D*), and pseudorapidity of the D* meson, eta(D*), have been measured in the kinematic region 0.02 < y < 0.85, 1.5 < p_T(D*) < 9.0 GeV and |eta(D*)| < 1.5. The measured differential cross sections are in agreement with two different NLO QCD calculations. The cross sections are also compared to previous ZEUS measurements in the photoproduction and DIS regimes.

Chekanov, S; Abt, I; Adamczyk, L; Adamus, M; Adler, V; Allfrey, P D; Antonelli, S; Antonioli, P; Antonov, A; Arneodo, M; Bamberger, A; Barakbaev, A N; Barbagli, G; Bari, G; Barreiro, F; Bartsch, D; Basile, M; Behrens, U; Bell, M A; Bellagamba, L; Bellan, P; Bertolin, A; Bhadra, S; Bindi, M; Bloch, I; Blohm, C; Bold, T; Bonato, A; Boos, E G; Borras, K; Boscherini, D; Boutle, S K; Brock, I; Brook, N H; Brownson, E; Brugnera, R; Bruni, A; Bruni, G; Brzozowska, B; Brümmer, N; Bussey, P J; Butterworth, J M; Bylsma, B; Büttner, C; Caldwell, A; Capua, M; Carlin, R; Catterall, C D; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cifarelli, L; Cindolo, F; Cole, J E; Contin, A; Cooper-Sarkar, A M; Coppola, N; Corradi, M; Corriveau, F; Cottrell, A; Cui, Y; D'Agostini, G; Dal Corso, F; Danielson, T; De Favereau, J; De Pasquale, S; Del Peso, J; Dementiev, R K; Derrick, M; Devenish, R C E; Dobur, D; Dolgoshein, B A; Dossanov, A; Doyle, A T; Dunne, W; Durkin, L S; Dusini, S; Eisenberg, Y; Ermolov, P F; Eskreys, A; Estrada; Everett, A; Fazio, S; Ferrando, J; Ferrero, M I; Figiel, J; Foster, B; Foudas, C; Fourletov, S; Fourletova, J; Fry, C; Gabareen, A; Galas, A; Gallo, E; Garfagnini, A; Geiser, A; Gialas, I; Gil, M; Giller, I; Gladilin, L K; Gladkov, D; Glasman, C; Goers, S; Gosau, T; Grabowska-Bold, I; Gregor, I; Grigorescu, G; Grzelak, G; Gwenlan, C; Göttlicher, P; Haas, T; Hain, W; Hall-Wilton, R; Hamatsu, R; Hart, J C; Hartmann, H; Hartner, G; Heath, G P; Hilger, E; Hochman, D; Holm, U; Hori, R; Horn, C; Iacobucci, G; Ibrahim, Z A; Iga, Y; Ingbir, R; Irrgang, P; Jakob, H P; Jechow, M; Jiménez, M; Jones, T W; Jüngst, M; Kagawa, S; Kahle, B; Kaji, H; Kamaluddin, B; Kananov, S; Karshon, U; Karstens, F; Kataoka, M; Katkov, I I; Kcira, D; Keramidas, A; Khein, L A; Kim, J Y; Kind, O M; Kisielewska, D; Kitamura, S; Klanner, R; Klein, U; Koffeman, E; Kollar, D; Kooijman, P; Korcsak-Gorzo, K; Korzhavina, I A; Kotanski, A; Kowalski, H; Kulinski, P; Kuze, M; Kuzmin, V A; Kötz, U; Labarga, L; Lee, A; Levchenko, B B; Levy, A; Limentani, S; Ling, T Y; Liu, C; Lobodzinska, E; Lohmann, W; Lohrmann, E; Loizides, J H; Long, K R; Longhin, A; Lukasik, J; Lukina, O Yu; Luzniak, P; Löhr, B; Ma, K J; Magill, S; Malka, J; Mankel, R; Margotti, A; Marini, G; Martin, J F; Mastroberardino, A; Matsumoto, T; Mattingly, M C K; Melzer-Pellmann, I A; Menary, S; Miglioranzi, S; Monaco, V; Montanari, A; Morris, J D; Musgrave, B; Nagano, K; Namsoo, T; Nania, R; Nicholass, D; Nigro, A; Ning, Y; Noor, U; Notz, D; Nowak, R J; Nuncio-Quiroz, A E; Oh, B Y; Okazaki, N; Olkiewicz, K; Ota, O; Patel, S; Paul, E; Pavel, N; Pawlak, J M; Pelfer, P G; Pellegrino, A; Piotrzkowski, K; Plucinsky, P P; Pokrovskiy, N S; Polini, A; Proskuryakov, A S; Przybycien, M; Raval, A; Reeder, D D; Ren, Z; Renner, R; Repond, J; Ri, Y D; Rinaldi, L; Roberfroid, V; Robertson, A; Ron, E; Rosin, M; Rubinsky, I; Ruspa, M; Ryan, P; Sacchi, R; Salehi, H; Samson, U; Santamarta, R; Sartorelli, G; Savin, A A; Saxon, D H; Schioppa, M; Schlenstedt, S; Schleper, P; Schmidke, W B; Schneekloth, U; Schonberg, V; Schörner-Sadenius, T; Sciulli, F; Shcheglova, L M; Shehzadi, R; Shimizu, S; Skillicorn, I O; Slominski, W; Smith, W H; Soares, M; Solano, A; Son, D; Sosnovtsev, V; Spiridonov, A; Stadie, H; Stanco, L; Standage, J; Stifutkin, A; Stopa, P; Straub, P B; Suchkov, S; Susinno, G; Suszycki, L; Sutiak, J; Sutton, M R; Sztuk, J; Szuba, D; Szuba, J; Tapper, A D; Targett-Adams, C; Tassi, E; Tawara, T; Terron, J; Theedt, T; Tiecke, H; Tokushuku, K; Tsurugai, T; Turcato, M; Tymieniecka, T; Ukleja, A; Ukleja, J; Uribe-, C; Vlasov, N N; Vázquez, M; Walczak, R; Walsh, R; Wan-Abdullah, W A T; Whitmore, J J; Whyte, J; Wichmann, K; Wick, K; Wiggers, L; Wing, M; Wlasenko, M; Wolf, G; Wolfe, H; Wrona, K; Yagues-Molina, A G; Yamada, S; Yamazaki, Y; Yoshida, R; Youngman, C; Zambrana, M; Zarnecki, A F; Zawiejski, L; Zeuner, W; Zhautykov, B O; Zhou, C; Zichichi, A; Zotkin, D S; Zotkin, S A

2007-01-01

126

Thrombospondin-1 activation of signal-regulatory protein-? stimulates reactive oxygen species production and promotes renal ischemia reperfusion injury.  

PubMed

Ischemia reperfusion injury (IRI) causes tissue and organ injury, in part, through alterations in tissue blood flow and the production of reactive oxygen species. The cell surface receptor signal-regulatory protein-? (SIRP-?) is expressed on inflammatory cells and suppresses phagocytosis, but the function of SIRP-? in IRI has not been determined. We reported previously that the matricellular protein thrombospondin-1 is upregulated in IRI. Here, we report a novel interaction between thrombospondin-1 and SIRP-? on nonphagocytic cells. In cell-free experiments, thrombospondin-1 bound SIRP-?. In vascular smooth muscle cells and renal tubular epithelial cells, treatment with thrombospondin-1 led to phosphorylation of SIRP-? and downstream activation of Src homology domain 2-containing phosphatase-1. Thrombospondin-1 also stimulated phosphorylation of p47(phox) (an organizer subunit for nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 1/2) and increased production of superoxide, both of which were abrogated by knockdown or antibody blockade of SIRP-?. In rodent aortic rings, treatment with thrombospondin-1 increased the production of superoxide and inhibited nitric oxide-mediated vasodilation in a SIRP-?-dependent manner. Renal IRI upregulated the thrombospondin-1-SIRP-? signaling axis and was associated with increased superoxide production and cell death. A SIRP-? antibody that blocks thrombospondin-1 activation of SIRP-? mitigated the effects of renal IRI, increasing blood flow, suppressing production of reactive oxygen species, and preserving cellular architecture. A role for CD47 in SIRP-? activation in these pathways is also described. Overall, these results suggest that thrombospondin-1 binding to SIRP-? on nonphagocytic cells activates NADPH oxidase, limits vasodilation, and promotes renal IRI. PMID:24511121

Yao, Mingyi; Rogers, Natasha M; Csányi, Gábor; Rodriguez, Andres I; Ross, Mark A; St Croix, Claudette; Knupp, Heather; Novelli, Enrico M; Thomson, Angus W; Pagano, Patrick J; Isenberg, Jeffrey S

2014-06-01

127

Deeply Virtual Compton Scattering and Meson Production at Jlab/CLAS  

SciTech Connect

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

Hyon-Suk Jo

2012-04-01

128

Differential contribution of the mitochondrial respiratory chain complexes to reactive oxygen species production by redox cycling agents implicated in parkinsonism.  

PubMed

Exposure to environmental pesticides can cause significant brain damage and has been linked with an increased risk of developing neurodegenerative disorders, including Parkinson's disease. Bipyridyl herbicides, such as paraquat (PQ), diquat (DQ), and benzyl viologen (BV), are redox cycling agents known to exert cellular damage through the production of reactive oxygen species (ROS). We examined the involvement of the mitochondrial respiratory chain in ROS production by bipyridyl herbicides. In isolated rat brain mitochondria, H2O2 production occurred with the following order of potency: BV > DQ > PQ in accordance with their measured ability to redox cycle. H2O2 production was significantly attenuated in all cases by antimycin A, an inhibitor of complex III. Interestingly, at micromolar (< or = 300 microM) concentrations, PQ-induced H2O2 production was unaffected by complex I inhibition via rotenone, whereas DQ-induced H2O2 production was equally attenuated by inhibition of complex I or III. Moreover, complex I inhibition decreased BV-induced H2O2 production to a greater extent than with PQ or DQ. These data suggest that multiple sites within the respiratory chain contribute to H2O2 production by redox cycling bipyridyl herbicides. In primary midbrain cultures, H2O2 differed slightly with the following order of potency: DQ > BV > PQ. In this model, inhibition of complex III resulted in roughly equivalent inhibition of H2O2 production with all three compounds. These data identify a novel role for complex III dependence of mitochondrial ROS production by redox cycling herbicides, while emphasizing the importance of identifying mitochondrial mechanisms by which environmental agents generate oxidative stress contributing to parkinsonism. PMID:19767442

Drechsel, Derek A; Patel, Manisha

2009-12-01

129

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

Microsoft Academic Search

Inclusive production of D*± (2010) mesons in deep inelastic scattering has been measured with the ZEUS detector at DESY HERA using an integrated luminosity of 81.9 pb-1. The decay channel D*+-->D0pi+ with D0-->K-pi+ and corresponding antiparticle decay were used to identify D* mesons. Differential D* cross sections with 1.5

S. V. Chekanov; M. Derrick; D. Krakauer; J. H. Loizides; S. Magill; B. Musgrave; J. Repond; R. Yoshida; M. C. Mattingly; P. Antonioli; G. Bari; M. Basile; L. Bellagamba; D. Boscherini; A. Bruni; G. Bruni; G. Cara Romeo; L. Cifarelli; F. Cindolo; A. Contin; M. Corradi; S. de Pasquale; P. Giusti; G. Iacobucci; A. Margotti; A. Montanari; R. Nania; F. Palmonari; A. Pesci; G. Sartorelli; A. Zichichi; G. Aghuzumtsyan; D. Bartsch; I. Brock; S. Goers; H. Hartmann; E. Hilger; P. Irrgang; H.-P. Jakob; A. Kappes; U. F. Katz; O. Kind; U. Meyer; E. Paul; J. Rautenberg; R. Renner; A. Stifutkin; J. Tandler; K. C. Voss; M. Wang; A. Weber; D. S. Bailey; N. H. Brook; J. E. Cole; B. Foster; G. P. Heath; H. F. Heath; S. Robins; E. Rodrigues; J. Scott; R. J. Tapper; M. Wing; M. Capua; A. Mastroberardino; M. Schioppa; G. Susinno; J. Y. Kim; Y. K. Kim; J. H. Lee; I. T. Lim; M. Y. Pac; A. Caldwell; M. Helbich; X. Liu; B. Mellado; Y. Ning; S. Paganis; Z. Ren; W. B. Schmidke; F. Sciulli; J. Chwastowski; A. Eskreys; J. Figiel; K. Olkiewicz; P. Stopa; L. Zawiejski; L. Adamczyk; T. Bold; I. Grabowska-Bold; D. Kisielewska; A. M. Kowal; M. Kowal; T. Kowalski; M. Przybycien; L. Suszycki; D. Szuba; J. Szuba; A. Kotanski; W. Slominski; V. Adler; L. A. Bauerdick; U. Behrens; I. Bloch; K. Borras; V. Chiochia; D. Dannheim; G. Drews; J. Fourletova; U. Fricke; A. Geiser; P. Göttlicher; O. Gutsche; T. Haas; W. Hain; G. F. Hartner; S. Hillert; B. Kahle; U. Kötz; H. Kowalski; G. Kramberger; H. Labes; D. Lelas; B. Löhr; R. Mankel; I.-A. Melzer-Pellmann; C. N. Nguyen; D. Notz; A. E. Nuncio-Quiroz; M. C. Petrucci; A. Polini; A. Raval; L. Rurua; U. Schneekloth; U. Stoesslein; G. Wolf; C. Youngman; W. Zeuner; S. Schlenstedt; G. Barbagli; E. Gallo; C. Genta; P. G. Pelfer; A. Bamberger; A. Benen; N. Coppola; M. Bell; P. J. Bussey; A. T. Doyle; S. Hanlon; S. W. Lee; A. Lupi; D. H. Saxon; I. O. Skillicorn; I. Gialas; B. Bodmann; T. Carli; U. Holm; K. Klimek; N. Krumnack; E. Lohrmann; M. Milite; H. Salehi; P. Schleper; S. Stonjek; K. Wick; A. Ziegler; C. Collins-Tooth; C. Foudas; R. Gonçalo; K. R. Long; A. D. Tapper; P. Cloth; D. Filges; K. Nagano; K. Tokushuku; S. Yamada; Y. Yamazaki; M. Kataoka; A. N. Barakbaev; E. G. Boos; N. S. Pokrovskiy; B. O. Zhautykov; H. Lim; D. Son; K. Piotrzkowski; F. Barreiro; C. Glasman; O. González; L. Labarga; J. del Peso; E. Tassi; J. Terrón; M. Vázquez; M. Barbi; F. Corriveau; S. Gliga; J. Lainesse; S. Padhi; D. G. Stairs; R. Walsh; T. Tsurugai; A. Antonov; P. Danilov; B. A. Dolgoshein; D. Gladkov; V. Sosnovtsev; S. Suchkov; R. K. Dementiev; P. F. Ermolov; Yu. A. Golubkov; I. I. Katkov; L. A. Khein; I. A. Korzhavina; V. A. Kuzmin; B. B. Levchenko; O. Yu. Lukina; A. S. Proskuryakov; L. M. Shcheglova; N. N. Vlasov; S. A. Zotkin; S. Grijpink; E. Koffeman; P. Kooijman; E. Maddox; A. Pellegrino; S. Schagen; H. Tiecke; J. J. Velthuis; L. Wiggers; E. de Wolf; N. Brümmer; B. Bylsma; L. S. Durkin; T. Y. Ling; A. M. Cooper-Sarkar; A. Cottrell; R. C. Devenish; J. Ferrando; G. Grzelak; C. Gwenlan; S. Patel; M. R. Sutton; R. Walczak; A. Bertolin; R. Brugnera; R. Carlin; F. dal Corso; S. Dusini; A. Garfagnini; S. Limentani; A. Longhin; A. Parenti; M. Posocco; L. Stanco; M. Turcato; E. A. Heaphy; F. Metlica; B. Y. Oh; J. J. Whitmore; Y. Iga; G. D'Agostini; G. Marini; A. Nigro; C. Cormack; J. C. Hart; N. A. McCubbin; C. Heusch; I. H. Park; N. Pavel; H. Abramowicz; A. Gabareen; S. Kananov; A. Kreisel; A. Levy; M. Kuze; T. Abe; T. Fusayasu; S. Kagawa; T. Kohno; T. Tawara; T. Yamashita; R. Hamatsu; T. Hirose; M. Inuzuka; H. Kaji; S. Kitamura; K. Matsuzawa; T. Nishimura; M. Arneodo; M. I. Ferrero; V. Monaco; M. Ruspa; R. Sacchi; A. Solano; T. Koop; G. M. Levman; J. F. Martin; A. Mirea; J. M. Butterworth; R. Hall-Wilton; T. W. Jones; M. S. Lightwood; C. Targett-Adams; J. Ciborowski; R. Ciesielski; P. Luzniak; R. J. Nowak; J. M. Pawlak; J. Sztuk; T. Tymieniecka; A. Ukleja; J. Ukleja; A. F. Zarnecki; M. Adamus; P. Plucinski; Y. Eisenberg; L. K. Gladilin; D. Hochman; U. Karshon; M. Riveline; D. Kçira; S. Lammers; L. Li; D. D. Reeder; M. Rosin; A. A. Savin; W. H. Smith; A. Deshpande; S. Dhawan; P. B. Straub; S. Bhadra; C. D. Catterall; S. Fourletov; S. Menary; M. Soares; J. Standage

2004-01-01

130

Multijet production at low x Bj in deep inelastic scattering at HERA  

Microsoft Academic Search

Inclusive dijet and trijet production in deep inelastic ep scattering has been measured for 10Q2100 GeV2 and low Bjorken x, 10?4xBj10?2. The data were taken at the HERA ep collider with centre-of-mass energy s=318 GeV using the ZEUS detector and correspond to an integrated luminosity of 82 pb?1. Jets were identified in the hadronic centre-of-mass (HCM) frame using the kT cluster algorithm in

S. Bhadra; C. D. Catterall; Y. Cui; G. Hartner; S. Menary; U. Noor; J. Standage; J. Whyte; M. C. K. Mattingly; M. Jechow; N. Pavel; A. G. Yagües Molina; S. Antonelli; P. Antonioli; G. Bari; M. Basile; L. Bellagamba; M. Bindi; D. Boscherini; A. Bruni; G. Bruni; L. Cifarelli; F. Cindolo; A. Contin; M. Corradi; S. de Pasquale; G. Iacobucci; A. Margotti; R. Nania; A. Polini; G. Sartorelli; A. Zichichi; D. Bartsch; I. Brock; S. Goers; H. Hartmann; E. Hilger; H.-P. Jakob; M. Jüngst; O. M. Kind; A. E. Nuncio-Quiroz; E. Paul; R. Renner; U. Samson; V. Schönberg; R. Shehzadi; M. Wlasenko; N. H. Brook; G. P. Heath; J. D. Morris; T. Namsoo; M. Capua; S. Fazio; A. Mastroberardino; M. Schioppa; G. Susinno; E. Tassi; J. Y. Kim; K. J. Ma; Z. A. Ibrahim; B. Kamaluddin; W. A. T. Wan Abdullah; Y. Ning; Z. Ren; F. Sciulli; J. Chwastowski; A. Eskreys; J. Figiel; A. Galas; M. Gil; K. Olkiewicz; P. Stopa; L. Zawiejski; L. Adamczyk; T. Bold; I. Grabowska-Bold; D. Kisielewska; J. Lukasik; M. Przybycien; L. Suszycki; A. Kotanski; W. Slominski; V. Adler; U. Behrens; I. Bloch; C. Blohm; A. Bonato; K. Borras; R. Ciesielski; N. Coppola; A. Dossanov; V. Drugakov; J. Fourletova; A. Geiser; D. Gladkov; P. Göttlicher; J. Grebenyuk; I. Gregor; T. Haas; W. Hain; C. Horn; A. Hüttmann; B. Kahle; I. I. Katkov; U. Klein; U. Kötz; H. Kowalski; E. Lobodzinska; B. Löhr; R. Mankel; I.-A. Melzer-Pellmann; S. Miglioranzi; A. Montanari; D. Notz; L. Rinaldi; P. Roloff; I. Rubinsky; R. Santamarta; U. Schneekloth; A. Spiridonov; H. Stadie; D. Szuba; J. Szuba; T. Theedt; G. Wolf; K. Wrona; C. Youngman; W. Zeuner; W. Lohmann; S. Schlenstedt; G. Barbagli; E. Gallo; P. G. Pelfer; A. Bamberger; D. Dobur; F. Karstens; N. N. Vlasov; P. J. Bussey; A. T. Doyle; W. Dunne; J. Ferrando; M. Forrest; D. H. Saxon; I. O. Skillicorn; I. Gialas; K. Papageorgiu; T. Gosau; U. Holm; R. Klanner; E. Lohrmann; H. Salehi; P. Schleper; T. Schörner-Sadenius; J. Sztuk; K. Wichmann; K. Wick; C. Foudas; C. Fry; K. R. Long; A. D. Tapper; M. Kataoka; T. Matsumoto; K. Nagano; K. Tokushuku; S. Yamada; Y. Yamazaki; A. N. Barakbaev; E. G. Boos; N. S. Pokrovskiy; B. O. Zhautykov; V. Aushev; D. Son; J. de Favereau; K. Piotrzkowski; F. Barreiro; C. Glasman; M. Jimenez; L. Labarga; J. Del Peso; E. Ron; M. Soares; J. Terrón; M. Zambrana; F. Corriveau; C. Liu; R. Walsh; C. Zhou; T. Tsurugai; A. Antonov; B. A. Dolgoshein; V. Sosnovtsev; A. Stifutkin; S. Suchkov; R. K. Dementiev; P. F. Ermolov; L. K. Gladilin; L. A. Khein; I. A. Korzhavina; V. A. Kuzmin; B. B. Levchenko; O. Yu. Lukina; A. S. Proskuryakov; L. M. Shcheglova; D. S. Zotkin; S. A. Zotkin; I. Abt; C. Büttner; A. Caldwell; D. Kollar; W. B. Schmidke; J. Sutiak; G. Grigorescu; A. Keramidas; E. Koffeman; P. Kooijman; A. Pellegrino; H. Tiecke; M. Vázquez; L. Wiggers; N. Brümmer; B. Bylsma; L. S. Durkin; A. Lee; T. Y. Ling; P. D. Allfrey; M. A. Bell; A. M. Cooper-Sarkar; A. Cottrell; R. C. E. Devenish; B. Foster; K. Korcsak-Gorzo; S. Patel; V. Roberfroid; A. Robertson; P. B. Straub; C. Uribe-Estrada; R. Walczak; P. Bellan; A. Bertolin; R. Brugnera; R. Carlin; F. Dal Corso; S. Dusini; A. Garfagnini; S. Limentani; A. Longhin; L. Stanco; M. Turcato; B. Y. Oh; A. Raval; J. Ukleja; J. J. Whitmore; Y. Iga; G. D'Agostini; G. Marini; A. Nigro; J. E. Cole; J. C. Hart; H. Abramowicz; A. Gabareen; R. Ingbir; S. Kananov; A. Levy; M. Kuze; J. Maeda; R. Hori; S. Kagawa; N. Okazaki; S. Shimizu; T. Tawara; R. Hamatsu; H. Kaji; S. Kitamura; O. Ota; Y. D. Ri; M. I. Ferrero; V. Monaco; R. Sacchi; A. Solano; M. Arneodo; M. Ruspa; S. Fourletov; J. F. Martin; S. K. Boutle; J. M. Butterworth; C. Gwenlan; T. W. Jones; J. H. Loizides; M. R. Sutton; M. Wing; B. Brzozowska; J. Ciborowski; G. Grzelak; P. Kulinski; P. Luzniak; J. Malka; R. J. Nowak; J. M. Pawlak; T. Tymieniecka; A. Ukleja; A. F. Zarnecki; M. Adamus; P. Plucinski; Y. Eisenberg; I. Giller; D. Hochman; U. Karshon; M. Rosin; E. Brownson; T. Danielson; A. Everett; D. Kçira; D. D. Reeder; P. Ryan; A. A. Savin; W. H. Smith; H. Wolfe

2007-01-01

131

Elements of a non-Hermitian quantum theory without Hermitian conjugation - scalar product and scattering  

E-print Network

The descripition of in a Hermitian setting seemingly nonlocal and nonperturbative phenomena like confinement or superconductivity is most conveniently performed by generalizing quantum theory to a non-Hermitian regime where these phenomena appear perturbative and local. The short presentation provides a clue how this can be done on the basis of Lorentz covariance while preserving the analyticity of the theory. After deriving with the help of Lorentz covariance a quantum scalar product without making any use of metric or complex conjugation we sketch how the formalism of scattering theory can be extended analytically to a non-Hermitian regime.

Kleefeld, Frieder

2015-01-01

132

Backward elastic scattering and ? - production in ?-p collisions at 10 GeV/ c  

NASA Astrophysics Data System (ADS)

The reactions ?-p ? p ?- and ?-p ? p ?- ( ?- ? ?-?0) at 10 GeV/ c with the proton in the forward direction in the c.m.s. are discussed on the basis of 953 elastic scattering events and 2240 events of the reaction ?-p ? p ?-?0. The total backward cross sections are 0.52±0.10 and 1.52±0.28 ?b, respectively. In both cases the production mechanism is compatible with the dominance of the baryonic ?? Regge trajectory exchange. The ? - decay angular distributions are studied in the u-channel helicity frame and the spin density matrix elements are presented as functions of u.

Ghidini, B.; Lenti, V.; Palano, A.; Paul, E.; French, B. R.; Hughes, I. S.; Turnbull, R. M.; Donald, R. A.; Costa, G.; Mandelli, L.; Perini, L.; Mitaroff, W. A.; Bari-Bonn-CERN-Glasgow-Liverpool-Milan-Vienna Collaboration

1982-02-01

133

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

SciTech Connect

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.

Jenkins, James P [Los Alamos National Laboratory; Goldman, Terry J [Los Alamos National Laboratory

2009-01-01

134

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

SciTech Connect

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

Yuan, Feng; Yuan, Feng

2008-04-14

135

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

PubMed Central

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

1983-01-01

136

Increased reactive oxygen species production and p47phox phosphorylation in neutrophils from myeloproliferative disorders patients with JAK2 (V617F) mutation  

PubMed Central

Myeloproliferative disorders are associated with increased risk of thrombosis and vascular complications. The pathogenesis of these complications is not completely known. Reactive oxygen species produced by the neutrophil NADPH oxidase could have a role in this process. The aim of this study was to evaluate reactive oxygen species production by neutrophils of myeloproliferative disorder patients. Patients with or without the JAK2 V617F mutation were characterized. Reactive oxygen species production was assessed by chemiluminescence, and phosphorylation of the NADPH oxidase subunit p47phox was analyzed by Western blots. In a comparison of controls and myeloproliferative disorder patients without the JAK2 V617F mutation, reactive oxygen species production by neutrophils from patients with the JAK2 V617F mutation was dramatically increased in non-stimulated and in stimulated conditions. This increase was associated with increased phosphorylation of the p47phox on Ser345 and of the uspstream kinase ERK1/2. In neutrophils from healthy donors, JAK2 can be activated by GM-CSF. GM-CSF-induced p47phox phosphorylation and priming of reactive oxygen species production are inhibited by the selective JAK2 inhibitors AG490 and lestaurtinib (CEP-701), supporting a role for JAK2 in the upregulation of NADPH oxidase activation. These findings show an increase in reactive oxygen species production and p47phox phosphorylation in neutrophils from myeloproliferative disorder patients with the JAK2 V617F mutation, and demonstrate that JAK2 is involved in GM-CSF-induced NADPH oxidase hyperactivation. As neutrophil hyperactivation could be implicated in the thrombophilic status of patients with myeloproliferative disorders, aberrant activation of JAK2 V617F, leading to excessive neutrophil reactive oxygen species production might play a role in this setting. PMID:23975181

Hurtado-Nedelec, Margarita; Csillag-Grange, Marie-José; Boussetta, Tarek; Belambri, Sahra Amel; Fay, Michèle; Cassinat, Bruno; Gougerot-Pocidalo, Marie-Anne; Dang, Pham My-Chan; El-Benna, Jamel

2013-01-01

137

A key enzyme for flavin synthesis is required for nitric oxide and reactive oxygen species production in disease resistance.  

PubMed

Nitric oxide (NO) and reactive oxygen species (ROS) play key roles in plant immunity. However, the regulatory mechanisms of the production of these radicals are not fully understood. Hypersensitive response (HR) cell death requires the simultaneous and balanced production of NO and ROS. In this study we indentified NbRibAencoding a bifunctional enzyme, guanosine triphosphate cyclohydrolase II/3,4-dihydroxy-2-butanone-4-phosphate synthase, which participates in the biosynthesis of flavin, by screening genes related to mitogen-activated protein kinase-mediated cell death, using virus-induced gene silencing. Levels of endogenous riboflavin and its derivatives, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), which are important prosthetic groups for several enzymes participating in redox reactions, decreased in NbRibA-silenced Nicotiana benthamiana. Silencing NbRibA compromised not only HR cell death, but also the NO and ROS production induced by INF1 elicitin and a constitutively active form of NbMEK2 (NbMEK2DD), and also induced high susceptibility to oomycete Phytophthora infestans and ascomycete Colletotrichum orbiculare. Compromised radical production and HR cell death induced by INF1 in NbRibA-silenced leaves were rescued by adding riboflavin, FMN or FAD. These results indicate that flavin biosynthesis participates in regulating NO and ROS production, and HR cell death. PMID:20230506

Asai, Shuta; Mase, Keisuke; Yoshioka, Hirofumi

2010-06-01

138

Ca2+ Regulates Reactive Oxygen Species Production and pH during Mechanosensing in Arabidopsis Roots[C][W  

PubMed Central

Mechanical stimulation of plants triggers a cytoplasmic Ca2+ increase that is thought to link the touch stimulus to appropriate growth responses. We found that in roots of Arabidopsis thaliana, external and endogenously generated mechanical forces consistently trigger rapid and transient increases in cytosolic Ca2+ and that the signatures of these Ca2+ transients are stimulus specific. Mechanical stimulation likewise elicited an apoplastic alkalinization and cytoplasmic acidification as well as apoplastic reactive oxygen species (ROS) production. These responses showed the same kinetics as mechanically induced Ca2+ transients and could be elicited in the absence of a mechanical stimulus by artificially increasing Ca2+ concentrations. Both pH changes and ROS production were inhibited by pretreatment with a Ca2+ channel blocker, which also inhibited mechanically induced elevations in cytosolic Ca2+. In trichoblasts of the Arabidopsis root hair defective2 mutant, which lacks a functional NADPH oxidase RBOH C, touch stimulation still triggered pH changes but not the local increase in ROS production seen in wild-type plants. Thus, mechanical stimulation likely elicits Ca2+-dependent activation of RBOH C, resulting in ROS production to the cell wall. This ROS production appears to be coordinated with intra- and extracellular pH changes through the same mechanically induced cytosolic Ca2+ transient. PMID:19654264

Monshausen, Gabriele B.; Bibikova, Tatiana N.; Weisenseel, Manfred H.; Gilroy, Simon

2009-01-01

139

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

PubMed Central

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

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

2002-01-01

140

In vitro study of reactive oxygen species production during photodynamic therapy in ultrasound-pretreated cancer cells.  

PubMed

Several recent studies bring evidence of cell death enhancement in photodynamic compound loaded cells by ultrasonic treatment. There are a number of hypotheses suggesting the mechanism of the harmful ultrasonic effect. One of them considers a process in the activation of photosensitizers by ultrasonic energy. Because the basis of the photodynamic damaging effect on cells consists in the production of reactive oxygen species (ROS), we focused our study on whether the ultrasound can increase ROS production within cancer cells. Particularly, we studied ROS formation in ultrasound pretreated breast adenocarcinoma cells during photodynamic therapy in the presence of chloroaluminum phthalocyanine disulfonate (ClAlPcS2). Production of ROS was investigated by the molecular probe CM-H2DCFDA. Our results show that ClAlPcS2 induces higher ROS production in the ultrasound pretreated cell lines at a concentration of 100 microM and light intensity of 2 mW/cm2. We also observed a dependence of ROS production on photosensitizer concentration and light dose. These results demonstrate that the photodynamic effect on breast cancer cells can be enhanced by ultrasound pretreatment. PMID:17552898

Kolárová, H; Bajgar, R; Tománková, K; Krestýn, E; Dolezal, L; Hálek, J

2007-01-01

141

Crossed-beam reactive scattering of F2 plus C6H6: Heat of formation of ipso-fluorocyclohexadienyl radical  

NASA Astrophysics Data System (ADS)

Angular distributions and relative total cross sections were measured for products of the collisions of F2 with C6 H6 at relative collision energies of 14 to 26 kcal mol-1 . The most conspicuous product is the ipso-fluorocyclohexadienyl radical i-C6 H6 F ?, which displays a rather narrow peak very near the center-of-mass angle at all collision energies studied. Product C6 H5 F is masked at M/e=96 by dissociative ionization of C6 H6 F ? near the center-of-mass angle, but becomes observable at smaller angles to which little or no C6 H6 F ? is scattered. This means that at least one reaction C6 H6 +F2 ?C6 H5 F+HF occurs, and does so in such a way that the products acquire high translational energies. The dependence on collision energy of the total cross section for the production of C6 H6 F ? was probably measured, and displays a well-marked onset at 13.9±0.3 kcal mol-1. The center-of-mass system means final state translational energy as a function of collision energy was obtained from the angular distributions and goes to zero at 13.9±0.5 kcal mol-1 . This probably means that the onset is a true threshold, from which the heat of formation of the ipso-fluorocyclohexadienyl radical is calculated to be 14.8±0.4 kcal mol-1. The mean final state translational energy asymptotically approaches 3.7 kcal mol-1 as the collision energies are increased, which is so large that only a fraction of the vibrational modes of C6 H6 F ? can be involved in the energy partitioning. This conclusion is confirmed by the center-of-mass angular distribution, which favors forward scattering of product F atoms, but only by about 10%-30%. This work shows that the crossed-beam method can be used to make precision thermochemical measurements of gaseous polyatomic free radicals. It also reports the investigation of a polyatomic-polyatomic reaction in crossed beams, for which type of study there are still very few examples.

Grover, J. R.; Wen, Y.; Lee, Y. T.; Shobatake, K.

1988-07-01

142

Nonlinear pair production in scattering of photons on ultra-short laser pulses at high energy  

E-print Network

We consider scattering of a photon on a short intense laser pulse at high energy. We argue that for ultra-short laser pulses the interaction is coherent over the entire length of the pulse. At low pulse intensity $I$ the total cross section for electron-positron pair production is proportional to $I$. However, at pulse intensities higher than the characteristic value $I_s$, the total cross section saturates -- it becomes proportional to the logarithm of intensity. This nonlinear effect is due to multi-photon interactions. We derive the total cross section for pair production at high energies by resuming the multi-photon amplitudes to all orders in intensity. We calculate the saturation intensity $I_s$ and show that it is significantly lower than the Schwinger's critical value. We discuss possible experimental tests.

Kirill Tuchin

2010-02-15

143

Transverse spin effects in hadron-pair production from semi-inclusive deep inelastic scattering  

E-print Network

First measurements of azimuthal asymmetries in hadron-pair production in deep-inelastic scattering of muons on transversely polarised ^6LiD (deuteron) and NH_3 (proton) targets are presented. The data were taken in the years 2002-2004 and 2007 with the COMPASS spectrometer using a muon beam of 160 GeV/c at the CERN SPS. The asymmetries provide access to the transversity distribution functions, without involving the Collins effect as in single hadron production. The sizeable asymmetries measured on the NH_ target indicate non-vanishing u-quark transversity and two-hadron interference fragmentation functions. The small asymmetries measured on the ^6LiD target can be interpreted as indication for a cancellation of u- and d-quark transversities.

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

2012-06-01

144

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

SciTech Connect

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

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

2009-08-04

145

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

E-print Network

We study the azimuthal angular dependence of back-to-back di-jet production in unpolarized hadron scattering $H_A+H_B \\to J_1 + J_2 +X$, 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 di-jet is of two identical quarks ($J_q+J_q$) or a quark-antiquark pair ($J_q+J_{\\bar{q}}$), there is a $\\cos \\delta \\phi$ angular dependence of the di-jet, with $\\delta \\phi=\\phi_1-\\phi_2$, and $\\phi_1$ and $\\phi_2$ are the azimuthal angles of the two individual jets. In the case of $J_q+J_q$ 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 di-jet production at RHIC, showing that the color factor enhancement in the angular dependent of $J_q+J_q$ production will reverse the sign of the asymmetry.

Zhun Lu; Ivan Schmidt

2008-05-26

146

beta-aminobutyric acid primes an NADPH oxidase-dependent reactive oxygen species production during grapevine-triggered immunity.  

PubMed

The molecular mechanisms underlying the process of priming are poorly understood. In the present study, we investigated the early signaling events triggered by beta-aminobutyric acid (BABA), a well-known priming-mediated plant resistance inducer. Our results indicate that, in contrast to oligogalacturonides (OG), BABA does not elicit typical defense-related early signaling events nor defense-gene expression in grapevine. However, in OG-elicited cells pretreated with BABA, production of reactive oxygen species (ROS) and expression of the respiratory-burst oxidase homolog RbohD gene were primed. In response to the causal agent of downy mildew Plasmopara viticola, a stronger ROS production was specifically observed in BABA-treated leaves. This process was correlated with an increased resistance. The NADPH oxidase inhibitor diphenylene iodonium (DPI) abolished this primed ROS production and reduced the BABA-induced resistance (BABA-IR). These results suggest that priming of an NADPH oxidase-dependent ROS production contributes to BABA-IR in the Vitis-Plasmopara pathosystem. PMID:20615112

Dubreuil-Maurizi, Carole; Trouvelot, Sophie; Frettinger, Patrick; Pugin, Alain; Wendehenne, David; Poinssot, Benoît

2010-08-01

147

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

PubMed

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-H??? 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

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

2011-02-01

148

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

PubMed Central

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

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

2015-01-01

149

Heat shock induces production of reactive oxygen species and increases inner mitochondrial membrane potential in winter wheat cells.  

PubMed

Heat shock leads to oxidative stress. Excessive ROS (reactive oxygen species) accumulation could be responsible for expression of genes of heat-shock proteins or for cell death. It is known that in isolated mammalian mitochondria high protonic potential on the inner membrane actuates the production of ROS. Changes in viability, ROS content, and mitochondrial membrane potential value have been studied in winter wheat (Triticum aestivum L.) cultured cells under heat treatment. Elevation of temperature to 37-50°C was found to induce elevated ROS generation and increased mitochondrial membrane potential, but it did not affect viability immediately after treatment. More severe heat exposure (55-60°C) was not accompanied by mitochondrial potential elevation and increased ROS production, but it led to instant cell death. A positive correlation between mitochondrial potential and ROS production was observed. Depolarization of the mitochondrial membrane by the protonophore CCCP inhibited ROS generation under the heating conditions. These data suggest that temperature elevation leads to mitochondrial membrane hyperpolarization in winter wheat cultured cells, which in turn causes the increased ROS production. PMID:25540005

Fedyaeva, A V; Stepanov, A V; Lyubushkina, I V; Pobezhimova, T P; Rikhvanov, E G

2014-11-01

150

Prolonged production of reactive oxygen species in response to BCR stimulation promotes B cell activation and proliferation  

PubMed Central

We have investigated the intracellular sources and physiological function of reactive oxygen species (ROS) produced in primary B cells in response to B cell antigen receptor (BCR) stimulation. BCR stimulation of primary resting murine B cells induced the rapid production of ROS that occurred within minutes, and was maintained for at least 24 h following receptor stimulation. While the early production of ROS (0-2 h) was dependent on the Nox2 isoform of NADPH oxidase, at later stages of B cell activation (6-24 h) ROS were generated by a second pathway, which appeared to be dependent on mitochondrial respiration. B cells from mice deficient in the Nox2 NADPH oxidase complex lacked detectible early production of extracellular and intracellular ROS following BCR stimulation, but had normal proximal BCR signaling and BCR-induced activation and proliferation in vitro, and mounted normal or somewhat elevated antibody responses in vivo. In contrast, neutralizing both pathways of BCR-derived ROS with the scavenger N-acetylcysteine resulted in impaired in vitro BCR-induced activation and proliferation, and attenuated BCR signaling through the phosphatidylinositol 3-kinase pathway at later times. These results indicate that the production of ROS downstream of the BCR is derived from at least two distinct cellular sources and plays a critical role at the later stages of B cell activation by promoting sustained BCR signaling via the PI3K pathway, which is needed for effective B cell responses to antigen. PMID:23024271

Wheeler, Matthew L.; DeFranco, Anthony L.

2012-01-01

151

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

PubMed

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 550°C showed the best activity. An optimum biodiesel yield of 98.5% was obtained under the reaction temperature of 50°C, 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

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

2014-12-01

152

Mobile Phone Radiation Induces Reactive Oxygen Species Production and DNA Damage in Human Spermatozoa In Vitro  

PubMed Central

Background In recent times there has been some controversy over the impact of electromagnetic radiation on human health. The significance of mobile phone radiation on male reproduction is a key element of this debate since several studies have suggested a relationship between mobile phone use and semen quality. The potential mechanisms involved have not been established, however, human spermatozoa are known to be particularly vulnerable to oxidative stress by virtue of the abundant availability of substrates for free radical attack and the lack of cytoplasmic space to accommodate antioxidant enzymes. Moreover, the induction of oxidative stress in these cells not only perturbs their capacity for fertilization but also contributes to sperm DNA damage. The latter has, in turn, been linked with poor fertility, an increased incidence of miscarriage and morbidity in the offspring, including childhood cancer. In light of these associations, we have analyzed the influence of RF-EMR on the cell biology of human spermatozoa in vitro. Principal Findings Purified human spermatozoa were exposed to radio-frequency electromagnetic radiation (RF-EMR) tuned to 1.8 GHz and covering a range of specific absorption rates (SAR) from 0.4 W/kg to 27.5 W/kg. In step with increasing SAR, motility and vitality were significantly reduced after RF-EMR exposure, while the mitochondrial generation of reactive oxygen species and DNA fragmentation were significantly elevated (P<0.001). Furthermore, we also observed highly significant relationships between SAR, the oxidative DNA damage bio-marker, 8-OH-dG, and DNA fragmentation after RF-EMR exposure. Conclusions RF-EMR in both the power density and frequency range of mobile phones enhances mitochondrial reactive oxygen species generation by human spermatozoa, decreasing the motility and vitality of these cells while stimulating DNA base adduct formation and, ultimately DNA fragmentation. These findings have clear implications for the safety of extensive mobile phone use by males of reproductive age, potentially affecting both their fertility and the health and wellbeing of their offspring. PMID:19649291

De Iuliis, Geoffry N.; Newey, Rhiannon J.; King, Bruce V.; Aitken, R. John

2009-01-01

153

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

PubMed

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

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

2015-01-30

154

Application of the nitroblue tetrazolium-reduction method for studies on the production of reactive oxygen species in insect haemocytes.  

PubMed

The in vitro generation of reactive oxygen species (ROS) in haemocytes of Galleria mellonella, Aporia crataegi, Dendrolimus sibiricus, Aglais urticae (Lepidoptera) and Gryllus bimaculatus (Orthoptera), was studied by the method of nitroblue tetrazolium (NBT) reduction. Formazan formation (product of NBT reduction) was observed in haemocytes of all the insects examined, except A. urticae. Lypopolysaccharide and zymosan reduced the number of NBT-positive cells after 1 h incubation and an increase was registered after 4 h incubation. The inhibitors of the respiratory chain enzyme (sodium azide) and melanogenesis (phenylthiourea) reduced formazan formation in nonactivated insect blood cells. No influence of sodium azide and phenylthiourea was found on the activated haemocytes. The results suggest that the generation of ROS in insect haemocytes occured as a result of processes such as respiration and melanization during phagocytosis and encapsulation. PMID:11545444

Glupov, V V; Khvoshevskaya, M F; Lozinskaya, Y L; Dubovski, I M; Martemyanov, V V; Sokolova, J Y

2001-01-01

155

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

PubMed

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

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

2012-01-01

156

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

SciTech Connect

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.

Chen Baoying [Department of Medicine, University of Hong Kong, Hong Kong (China); Department of Radiology, Tangdu Hospital, Fourth Military Medical University (China); Lam, Karen S.L. [Department of Medicine, University of Hong Kong, Hong Kong (China); Wang Yu [Genome Research Center, University of Hong Kong, Hong Kong (China); Wu Donghai [Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences (China); Lam, Michael C. [Department of Medicine, University of Hong Kong, Hong Kong (China); Shen Jiangang [School of Chinese Medicine, University of Hong Kong (China); Wong Laiching [Department of Medicine, University of Hong Kong, Hong Kong (China); Hoo, Ruby L.C. [Department of Medicine, University of Hong Kong, Hong Kong (China); Zhang Jialiang [Department of Medicine, University of Hong Kong, Hong Kong (China); Xu Aimin [Department of Medicine, University of Hong Kong, Hong Kong (China) and Genome Research Center, University of Hong Kong, Hong Kong (China)]. E-mail: amxu@hkucc.hku.hk

2006-03-10

157

Continuous Production of Biodiesel Via an Intensified Reactive/Extractive Process  

SciTech Connect

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.

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

2008-01-01

158

Chemiluminescent detection of induced reactive oxygen metabolite production of human polymorphonuclear leucocytes by anthophyllite asbestos.  

PubMed

Incidences of lung cancer and pleural plaque have been reported in relation to exposure to anthophyllite asbestos. To investigate the pathogenic mechanisms of anthophyllite, chemiluminescence (CL) detection of reactive oxygen metabolite (ROM) generation of human polymorphonuclear leucocytes (PMN) stimulated by anthophyllite asbestos was determined and compared with that of other asbestos and mineral fiber samples. When anthophyllite fiber sample was mixed with the luminol-primed PMN, high levels of CL which exhibited a specific time course characterized by two separate peaks were induced. The CL induced by anthophyllite sample was greater than that induced by chrysotile, crocidolite, and amosite asbestos. We further investigated the two peaks of CL using specific inhibitors of signal transduction mechanisms. The two peaks of CL by anthophyllite sample were different in sensitivity to cytochalasin B and genistein; the former relates to the cytoskeleton-dependent mechanism and the latter has been shown to inhibit tyrosine kinase, which resides in the pathway to cause PMN activation. The strong ROM reaction of PMN by anthophyllite suggests that the surface characteristics of the fiber may participate in the pathogenic mechanisms of anthophyllite asbestos. PMID:11896666

Iwata, Toyoto; Kohyama, Norihiko; Yano, Eiji

2002-01-01

159

Wogonin Induces Reactive Oxygen Species Production and Cell Apoptosis in Human Glioma Cancer Cells  

PubMed Central

Glioma is the most common primary adult brain tumor with poor prognosis because of the ease of spreading tumor cells to other regions of the brain. Cell apoptosis is frequently targeted for developing anti-cancer drugs. In the present study, we have assessed wogonin, a flavonoid compound isolated from Scutellaria baicalensis Georgi, induced ROS generation, endoplasmic reticulum (ER) stress and cell apoptosis. Wogonin induced cell death in two different human glioma cells, such as U251 and U87 cells but not in human primary astrocytes (IC 50 > 100 ?M). Wogonin-induced apoptotic cell death in glioma cells was measured by propidine iodine (PI) analysis, Tunnel assay and Annexin V staining methods. Furthermore, wogonin also induced caspase-9 and caspase-3 activation as well as up-regulation of cleaved PARP expression. Moreover, treatment of wogonin also increased a number of signature ER stress markers glucose-regulated protein (GRP)-78, GRP-94, Calpain I, and phosphorylation of eukaryotic initiation factor-2? (eIF2?). Treatment of human glioma cells with wogonin was found to induce reactive oxygen species (ROS) generation. Wogonin induced ER stress-related protein expression and cell apoptosis was reduced by the ROS inhibitors apocynin and NAC (N-acetylcysteine). The present study provides evidence to support the fact that wogonin induces human glioma cell apoptosis mediated ROS generation, ER stress activation and cell apoptosis. PMID:22949836

Tsai, Cheng-Fang; Yeh, Wei-Lan; Huang, Ssu Ming; Tan, Tzu-Wei; Lu, Dah-Yuu

2012-01-01

160

[Production of reactive oxygen species and scavenger treatment in nephrotoxic nephritis].  

PubMed

Role of reactive oxygen species (ROS) was studied in accelerated nephrotoxic nephritis (NTN) in rats. In this experimental model, histological examination, and luminol amplified chemiluminescence (CL) assay of peripheral polymorphonuclear neutrophils (PMN), peritoneal macrophages (M phi), and isolated glomeruli were performed time-sequentially. Effect of ROS scavengers were also examined in this experiment. Daily dosages of bovine liver catalase and SOD were 550,000 and 1,000 units respectively. After nephrotoxic IgG injection, CL of glomeruli increased strikingly attaining peak at day 1, and remained high until the end of the experiment. This increase of CL may have reflected the release of ROS by glomerular cells and/or infiltrating cells stimulated in situ. In fact, peripheral PMN and peritoneal M phi showed no increase of CL after nephrotoxic IgG injection. Glomerular cells increased as early as 3 hours after induction of nephritis. Accumulation of PMN was noted for the first three days, whereas that of M phi became prominent after 4 days. Favourable effect was obtained in terms of proteinuria by administration of catalase, only when catalase was given at initial 3 days of nephritis. The data suggest that generation of ROS reflected by increase of CL in glomeruli of NTN rats is attributable to the PMN and M phi infiltrated in glomeruli as well as glomerular resident cells per se. It is also suggested that glomerular PMN increasing in the early phase of NTN plays a considerable role in glomerular injury. PMID:1479715

Nakamura, K

1992-07-01

161

Loss of TRPML1 promotes production of reactive oxygen species: is oxidative damage a factor in mucolipidosis type IV?  

PubMed

TRPML1 (transient receptor potential mucolipin 1) is a lysosomal ion channel permeable to cations, including Fe2+. Mutations in MCOLN1, the gene coding for TRPML1, cause the LSD (lysosomal storage disease) MLIV (mucolipidosis type IV). The role of TRPML1 in the cell is disputed and the mechanisms of cell deterioration in MLIV are unclear. The demonstration of Fe2+ buildup in MLIV cells raised the possibility that TRPML1 dissipates lysosomal Fe2+ and prevents its accumulation. Since Fe2+ catalyses the production of ROS (reactive oxygen species), we set out to test whether or not the loss of TRPML1 promotes ROS production by Fe2+ trapped in lysosomes. Our data show that RPE1 (retinal pigmented epithelial 1) cells develop a punctate mitochondrial phenotype within 48 h of siRNA-induced TRPML1-KD (knockdown). This mitochondrial fragmentation was aggravated by Fe2+ exposure, but was reversed by incubation with the ROS chelator ?-Toc (?-tocopherol). The exposure of TRPML1-KD cells to Fe2+ led to loss of ??m (mitochondrial membrane potential), ROS buildup, lipid peroxidation and increased transcription of genes responsive to cytotoxic oxidative stress in TRPML1-KD cells. These data suggest that TRPML1 redistributes Fe2+ between the lysosomes and the cytoplasm. Fe2+ buildup caused by TRPML1 loss potentiates ROS production and leads to mitochondrial deterioration. Beyond suggesting a new model for MLIV pathogenesis, these data show that TRPML1's role in the cell extends outside lysosomes. PMID:24192042

Coblentz, Jessica; St Croix, Claudette; Kiselyov, Kirill

2014-01-15

162

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

PubMed

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

Lim, Steven; Lee, Keat Teong

2013-08-01

163

Asian Dust Particles Induce Macrophage Inflammatory Responses via Mitogen-Activated Protein Kinase Activation and Reactive Oxygen Species Production  

PubMed Central

Asian dust is a springtime meteorological phenomenon that originates in the deserts of China and Mongolia. The dust is carried by prevailing winds across East Asia where it causes serious health problems. Most of the information available on the impact of Asian dust on human health is based on epidemiological investigations, so from a biological standpoint little is known of its effects. To clarify the effects of Asian dust on human health, it is essential to assess inflammatory responses to the dust and to evaluate the involvement of these responses in the pathogenesis or aggravation of disease. Here, we investigated the induction of inflammatory responses by Asian dust particles in macrophages. Treatment with Asian dust particles induced greater production of inflammatory cytokines interleukin-6 and tumor necrosis factor-? (TNF-?) compared with treatment with soil dust. Furthermore, a soil dust sample containing only particles ?10??m in diameter provoked a greater inflammatory response than soil dust samples containing particles >10??m. In addition, Asian dust particles-induced TNF-? production was dependent on endocytosis, the production of reactive oxygen species, and the activation of nuclear factor-?B and mitogen-activated protein kinases. Together, these results suggest that Asian dust particles induce inflammatory disease through the activation of macrophages. PMID:24987712

Higashisaka, Kazuma; Fujimura, Maho; Taira, Mayu; Yoshida, Tokuyuki; Tsunoda, Shin-ichi; Baba, Takashi; Yamaguchi, Nobuyasu; Nabeshi, Hiromi; Yoshikawa, Tomoaki; Nasu, Masao; Tsutsumi, Yasuo

2014-01-01

164

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

PubMed Central

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

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

2014-01-01

165

The Stimulated Innate Resistance Event in Bordetella pertussis Infection Is Dependent on Reactive Oxygen Species Production  

PubMed Central

The exacerbated induction of innate immune responses in airways can abrogate diverse lung infections by a phenomenon known as stimulated innate resistance (StIR). We recently demonstrated that the enhancement of innate response activation can efficiently impair Bordetella pertussis colonization in a Toll-like receptor 4 (TLR4)-dependent manner. The aim of this work was to further characterize the effect of lipopolysaccharide (LPS) on StIR and to identify the mechanisms that mediate this process. Our results showed that bacterial infection was completely abrogated in treated mice when the LPS of B. pertussis (1 ?g) was added before (48 h or 24 h), after (24 h), or simultaneously with the B. pertussis challenge (107 CFU). Moreover, we detected that LPS completely cleared bacterial infection as soon as 2 h posttreatment. This timing suggests that the observed StIR phenomenon should be mediated by fast-acting antimicrobial mechanisms. Although neutrophil recruitment was already evident at this time point, depletion assays using an anti-GR1 antibody showed that B. pertussis clearance was achieved even in the absence of neutrophils. To evaluate the possible role of free radicals in StIR, we performed animal assays using the antioxidant N-acetyl cysteine (NAC), which is known to inactivate oxidant species. NAC administration blocked the B. pertussis clearance induced by LPS. Nitrite concentrations were also increased in the LPS-treated mice; however, the inhibition of nitric oxide synthetases did not suppress the LPS-induced bacterial clearance. Taken together, our results show that reactive oxygen species (ROS) play an essential role in the TLR4-dependent innate clearance of B. pertussis. PMID:23630952

Zurita, E.; Moreno, G.; Errea, A.; Ormazabal, M.; Rumbo, M.

2013-01-01

166

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

PubMed

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

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

2009-02-01

167

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

PubMed

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

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

2014-04-14

168

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

PubMed Central

The mitochondrial respiratory chain is a major generator of cellular oxidative stress, thought to be an underlying cause of the carcinogenic and ageing process in many tissues including skin. Previous studies of the relative contributions of the respiratory chain (RC) complexes I, II and III towards production of reactive oxygen species (ROS) have focussed on rat tissues and certainly not on human skin which is surprising as this tissue is regularly exposed to UVA in sunlight, a potent generator of cellular oxidative stress. In a novel approach we have used an array of established specific metabolic inhibitors and DHR123 fluorescence to study the relative roles of the mitochondrial RC complexes in cellular ROS production in 2 types of human skin cells. These include additional enhancement of ROS production by exposure to physiological levels of UVA. The effects within epidermal and dermal derived skin cells are compared to other tissue cell types as well as those harbouring a compromised mitochondrial status (Rho-zero A549). The results show that the complex II inhibitor, TTFA, was the only RC inhibitor to significantly increase UVA-induced ROS production in both skin cell types (P<0.05) suggesting that the role of human skin complex II in terms of influencing ROS production is more important than previously thought particularly in comparison to liver cells. Interestingly, two-fold greater maximal activity of complex II enzyme was observed in both skin cell types compared to liver (P<0.001). The activities of RC enzymes appear to decrease with increasing age and telomere length is correlated with ageing. Our study showed that the level of maximal complex II activity was higher in the MRC5/hTERT (human lung fibroblasts transfected with telomerase) cells than the corresponding wild type cells (P=0.0012) which can be considered (in terms of telomerase activity) as models of younger and older cells respectively. PMID:25460738

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

2014-01-01

169

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

PubMed Central

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

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

2014-01-01

170

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

PubMed

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

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

2014-08-19

171

Chlorination of fatty acids during water treatment disinfection: Reactivity and product identification  

Microsoft Academic Search

A series of fatty acids were subjected to conditions typical of water chlorination disinfection. Saturated fatty acids did not react with chlorine, however, unsaturated fatty acids were almost completely consumed after 1 hour. A number of chlorinated and oxygenated products of this reaction were tentatively identified using fast atom bombardment mass spectroraetry.

T. M. Gibson; J. Haley; M. Righton; C. D. Watts

1986-01-01

172

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...

173

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

E-print Network

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

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

2013-10-16

174

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

PubMed Central

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

Kondrashov, Alexey; Vranková, Stanislava; Dovinová, Ima; Šev?ík, Rudolf; Parohová, Jana; Barta, Andrej; Pechá?ová, Olga; Kovacsová, Maria

2012-01-01

175

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

PubMed Central

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

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

2014-01-01

176

Selective detection of diethylene glycol in toothpaste products using neutral desorption reactive extractive electrospray ionization tandem mass spectrometry.  

PubMed

A rapid, sensitive method based on neutral desorption (ND) reactive extractive electrospray ionization mass spectrometry (EESI-MS) has been established for the selective quantitative detection of diethylene glycol (DEG) in toothpaste products without any sample pretreatment. The sensitivity and specificity of DEG detection were enhanced by implementing selective ion/molecule reactions in the EESI process, featuring the EESI mass spectra with the characteristic signals of DEG. The method provided a low limit of detection (LOD) (approximately 0.00002%, weight percent of DEG in toothpaste), reasonable recovery (97.6-102.4%), and acceptable relative standard deviations (RSD < 8%, n = 8) for direct measuring of DEG in the spiked toothpaste samples. Trace amounts of DEG in commercial toothpaste products have been quantitatively detected without any sample manipulation. The results demonstrate that nonvolatile compounds such as DEG can be sensitively liberated using the neutral gas beam for quantitative detection from the extremely viscous toothpaste containing solid nanoparticles, showing that ND-EESI-MS is a useful tool for the rapid characterization of highly complex and/or viscous samples at molecular levels. PMID:19761215

Ding, Jianhua; Gu, Haiwei; Yang, Shuiping; Li, Ming; Li, Jianqiang; Chen, Huanwen

2009-10-15

177

Calcium-Dependent Protein Kinases Regulate the Production of Reactive Oxygen Species by Potato NADPH Oxidase [W][OA  

PubMed Central

Reactive oxygen species (ROS) are implicated in plant innate immunity. NADPH oxidase (RBOH; for Respiratory Burst Oxidase Homolog) plays a central role in the oxidative burst, and EF-hand motifs in the N terminus of this protein suggest possible regulation by Ca2+. However, regulatory mechanisms are largely unknown. We identified Ser-82 and Ser-97 in the N terminus of potato (Solanum tuberosum) St RBOHB as potential phosphorylation sites. An anti-phosphopeptide antibody (pSer82) indicated that Ser-82 was phosphorylated by pathogen signals in planta. We cloned two potato calcium-dependent protein kinases, St CDPK4 and St CDPK5, and mass spectrometry analyses showed that these CDPKs phosphorylated only Ser-82 and Ser-97 in the N terminus of St RBOHB in a calcium-dependent manner. Ectopic expression of the constitutively active mutant of St CDPK5, St CDPK5VK, provoked ROS production in Nicotiana benthamiana leaves. The CDPK-mediated ROS production was disrupted by knockdown of Nb RBOHB in N. benthamiana. The loss of function was complemented by heterologous expression of wild-type potato St RBOHB but not by a mutant (S82A/S97A). Furthermore, the heterologous expression of St CDPK5VK phosphorylated Ser-82 of St RBOHB in N. benthamiana. These results suggest that St CDPK5 induces the phosphorylation of St RBOHB and regulates the oxidative burst. PMID:17400895

Kobayashi, Michie; Ohura, Ikuko; Kawakita, Kazuhito; Yokota, Naohiko; Fujiwara, Masayuki; Shimamoto, Ko; Doke, Noriyuki; Yoshioka, Hirofumi

2007-01-01

178

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

PubMed Central

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

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

2011-01-01

179

Phenylethynyl reactive diluents  

NASA Technical Reports Server (NTRS)

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.

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

1995-01-01

180

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

Microsoft Academic Search

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

Yossi Buskila; Shai Farkash; Michal Hershfinkel; Yael Amitai

2005-01-01

181

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

PubMed

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

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

2005-11-15

182

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

SciTech Connect

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.

Reaugh, J E; Lee, E L

2002-07-01

183

Surface-enhanced Raman scattering for immunoassay based on the biocatalytic production of silver nanoparticles.  

PubMed

We have reported on a novel enzyme immunoassay method for the detection of protein using biocatalytic silver nanoparticles as an enhanced substrate based on surface-enhanced Raman scattering (SERS). First, ascorbic acid was converted from ascorbic acid 2-phosphate by alkaline phosphatase immobilized on polystyrene microwells after a typical sandwich immunoreaction. Then Ag(I) ions were reduced to silver nanoparticles by the obtained ascorbic acid, which would result in a SERS signal when Raman dyes were absorbed. Using human IgG as a model protein, a wide linear dynamic range (1 to 100 ng ml(-1)) was reached with a low detection limit (0.02 ng ml(-1)) under the optimized assay conditions. Moreover, the production of an enhanced substrate was chosen as the signaling element in this method, which demonstrates a new way for SERS-based quantitative detection. These results suggest that the application of SERS enhanced by biocatalytic production of metal nanopaticles holds a promising potential for a sensitive immunoassay. PMID:19276589

Chen, Jiwei; Luo, Yan; Liang, Yi; Jiang, Jianhui; Shen, Guoli; Yu, Ruqin

2009-03-01

184

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

NASA Astrophysics Data System (ADS)

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.

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

2011-08-01

185

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

PubMed Central

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

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

2011-01-01

186

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

PubMed

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

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

2001-05-01

187

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

PubMed Central

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

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

2014-01-01

188

Production of ultra-cold neutrons using Doppler-shifted Bragg scattering and an intense pulsed neutron spallation source  

Microsoft Academic Search

An analytic and a computer generated simulation of the production of Ultra-Cold Neutrons (UCN) is presented using Bragg scattering from a moving crystal to Doppler shift higher velocity neutrons into the UCN region. The calculation was carried out with a view toward its application at the Intense Pulsed Neutron Source (IPNS) now under construction at Argonne National Laboratory. This method

T. W. Dombeck; J. W. Lynn; S. Werner; T. Brun; J. Carpenter; V. Krohn; R. Ringo

1979-01-01

189

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

PubMed Central

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

Weissman, Lior; Garty, Jacob; Hochman, Ayala

2005-01-01

190

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

PubMed

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

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

2014-08-25

191

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

PubMed

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

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

2013-11-01

192

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

PubMed Central

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

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

2010-01-01

193

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

PubMed

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), H(2)O(2) concentration (0-4.44?mmol·L(-1)), and reaction time (5 minutes, 1 and 24?h). The following conditions: 35°C, 0.55?mmol·L(-1), and 1h, provided the best set of results of color removal for DMBLR (99%), DMBBLN (77%), DMR (94%), and RBBR (97%). It should be mentioned that only 5 minutes of reaction was enough to obtain 96% of decolorization for DMBLR and RBBR. After the decolorization reactions of DMBLR, DMR, and RBBR, it was possible to observe the reduction of Artemia salina mortality and the no significant increase in toxicity for the products generated from DMBBLN. PMID:21318147

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

2011-01-01

194

Methyl-thiophanate increases reactive oxygen species production and induces genotoxicity in rat peripheral blood.  

PubMed

Methylthiophanate is one of the widely used fungicides to control important fungal diseases of crops. The aim of this study was to elucidate the short-term hematoxicity and genotoxicity effects of methylthiophanate administered by intraperitoneal way at three doses (300, 500 and 700?mg/kg of body weight) after 24, 48 and 72?h. Our results showed, 24?h after methylthiophanate injection, a hematological perturbation such as red blood cells (p?products and malondialdehyde levels, in erythrocytes of methylthiophanate-treated rats with 300, 500 and 700?mg/kg of body weight, was also observed after 24?h of treatment (p?

Ben Amara, Ibtissem; Ben Saad, Hajer; Cherif, Boutheina; Elwej, Awatef; Lassoued, Saloua; Kallel, Choumous; Zeghal, Najiba

2014-12-01

195

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

PubMed

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

Zhou, Xiaoyuan; Rauchfuss, Thomas B

2013-02-01

196

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

PubMed Central

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

Nazarewicz, Rafal R.

2013-01-01

197

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

PubMed

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. PMID:25545062

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

198

Lanthanum ions intervened in enzymatic production and elimination of reactive oxygen species in leaves of rice seedlings under cadmium stress.  

PubMed

Rare earth elements at proper concentrations were observed to alleviate heavy metal stress. However, the potential mechanisms of alleviation are not clear. Thus, the present study focused on the mechanisms of lanthanum (La) ions on the generation and elimination of reactive oxygen species (ROS) production in leaves of rice seedlings hydroponically cultivated in 30?µM cadmium chloride (CdCl2) for 2 d. Results showed that the decline of superoxide (O2 ·?(-)) or hydrogen peroxide (H2O2) was attributed not only to the decreased expressions of nicotinamide adenine dinucleotide phosphate oxidases-related gene, protein synthesis, and isozymes, but also to the decrease of xanthine oxidase, diamine oxidase, and guaiacol peroxidases isozymes and activities. Genes and isozymes related to superoxide dismutase, catalase, and ascorbate peroxidase were also differentially upregulated to control ROS accumulation when proper concentrations of La were combined with 30?µM Cd. Based on the results, one may conclude that La at proper concentrations not only limited the generation of O2 ?·?(-) and H2O2 from the enzymatic sources but also promoted the elimination of O2 ?·?(-) and H2O2 via the upregulating expressions of antioxidant enzyme-related genes and activities in the rice seedling's leaves under Cd stress. PMID:24753051

Wang, Cheng-Run; Wang, Qin-Ying; Tian, Yuan; Zhang, Ji-Feng; Li, Zhi-Xiao; Cao, Peng; Zhu, Mei; Li, Ting-Ting

2014-07-01

199

Production of Reactive Oxygen Species by Multipotent Stromal Cells/Mesenchymal Stem Cells Upon Exposure to Fas Ligand  

PubMed Central

Multipotent stromal cells (MSCs) can be differentiated into osteoblasts and chondrocytes, making these cells candidates to regenerate cranio-facial injuries and lesions in long bones. A major problem with cell replacement therapy, however, is the loss of transplanted MSCs at the site of graft. Reactive oxygen species (ROS) and nonspecific inflammation generated at the ischemic site have been hypothesized to lead to MSCs loss; studies in vitro show MSCs dying both in the presence of ROS or cytokines like FasL. We questioned whether MSCs themselves may be the source of these death inducers, specifically whether MSCs produce ROS under cytokine challenge. On treating MSCs with FasL, we observed increased ROS production within 2 h, leading to apoptotic death after 6 h of exposure to the cytokine. N-acetyl cysteine, an antioxidant, is able to protect MSCs from FasL-induced ROS production and subsequent ROS-dependent apoptosis, though the MSCs eventually succumb to ROS-independent death signaling. Epidermal growth factor (EGF), a cell survival factor, is able to protect cells from FasL-induced ROS production initially; however, the protective effect wanes with continued FasL exposure. In parallel, FasL induces upregulation of the uncoupling protein UCP2, the main uncoupling protein in MSCs, which is not abrogated by EGF; however, the production of ROS is followed by a delayed apoptotic cell death despite moderation by UCP2. FasL-induced ROS activates the stress-induced MAPK pathways JNK and p38MAPK as well as ERK, along with the activation of Bad, a proapoptotic protein, and suppression of survivin, an antiapoptotic protein; the latter two key modulators of the mitochondrial death pathway. FasL by itself also activates its canonical extrinsic death pathway noted by a time-dependent degradation of c-FLIP and activation of caspase 8. These data suggest that MSCs participate in their own demise due to nonspecific inflammation, holding implications for replacement therapies. PMID:22526333

Rodrigues, Melanie; Turner, Omari; Stolz, Donna; Griffith, Linda G.; Wells, Alan

2013-01-01

200

Combination and QCD Analysis of Charm Production Cross Section Measurements in Deep-Inelastic ep Scattering at HERA  

E-print Network

Measurements of open charm production cross sections in deep-inelastic ep scattering at HERA from the H1 and ZEUS Collaborations are combined. Reduced cross sections sigma_red^{c\\bar{c}} for charm production are obtained in the kinematic range of photon virtuality 2.5combination method accounts for the correlations of the systematic uncertainties among the different data sets. The combined charm data together with the combined inclusive deep-inelastic scattering cross sections from HERA are used as input for a detailed NLO QCD analysis to study the influence of different heavy flavour schemes on the parton distribution functions. The optimal values of the charm mass as a parameter in these different schemes are obtained. The implications on the NLO predictions for W^{\\pm} and Z production cross sections at the LHC are investigated. Using the fixed flavour number scheme, the running mass of the charm quark is determined.

H1 Collaboration; ZEUS Collaboration

2012-11-06

201

Properties of inclusive hadron production in Deep Inelastic Scattering on heavy nuclei at low x  

E-print Network

In this paper we present a comprehensive study of inclusive hadron production in DIS at low $x$. Properties of the hadron spectrum are different in different kinematic regions formed by three relevant momentum scales: photon virtuality $Q^2$, hadron transverse momentum $k_T$ and the saturation momentum $Q_s(x)$. We investigate each kinematic region and derive the corresponding asymptotic formulas for the cross section at the leading logarithmic order. We also analyze the next-leading-order (NLO) corrections to the BFKL kernel that are responsible for the momentum conservation. In particular, we establish the asymptotic behavior of the forward elastic dipole--nucleus scattering amplitude at high energies deeply in the saturation regime and a modification of the pomeron intercept. We study the nuclear effect on the inclusive cross section using the nuclear modification factor and its logarithmic derivative. We argue that the later is proportional to the difference between the anomalous dimension of the gluon distribution in nucleus and in proton and thus is a direct measure of the coherence effects. To augment our arguments and present quantitative results we performed numerical calculations in the kinematic region that may be accessible by the future DIS experiments.

Kirill Tuchin; Dajing Wu

2012-03-04

202

Multijet production at low $x_{\\rm Bj}$ in deep inelastic scattering at HERA  

E-print Network

Inclusive dijet and trijet production in deep inelastic $ep$ scattering has been measured for $10

Chekanov, S; Magill, S; Musgrave, B; Nicholass, D; Repond, J; Yoshida, R; Mattingly, M C K; Jechow, M; Pavel, N; Yagues-Molina, A G; Antonelli, S; Antonioli, P; Bari, G; Basile, M; Bellagamba, L; Bindi, M; Boscherini, D; Bruni, A; Bruni, G; Cifarelli, L; Cindolo, F; Contin, A; Corradi, M; De Pasquale, S; Iacobucci, G; Margotti, A; Nania, R; Polini, A; Sartorelli, G; Zichichi, A; Bartsch, D; Brock, I; Goers, S; Hartmann, H; Hilger, E; Jakob, H P; Jüngst, M; Kind, O M; Nuncio-Quiroz, A E; Paul, E; Renner, R; Samson, U; Schonberg, V; Shehzadi, R; Wlasenko, M; Brook, N H; Heath, G P; Morris, J D; Namsoo, T; Capua, M; Fazio, S; Mastroberardino, A; Schioppa, M; Susinno, G; Tassi, E; Kim, J Y; Ma, K J; Ibrahim, Z A; Kamaluddin, B; Wan-Abdullah, W A T; Ning, Y; Ren, Z; Sciulli, F; Chwastowski, J; Eskreys, A; Figiel, J; Galas, A; Gil, M; Olkiewicz, K; Stopa, P; Zaw, I; Adamczyk, L; Bold, T; Grabowska-Bold, I; Kisielewska, D; Lukasik, J; Przybycien, M; Suszycki, L; Kotanski, A; Slominski, W; Adler, V; Behrens, U; Bloch, I; Blohm, C; Bonato, A; Borras, K; Ciesielski, R; Coppola, N; Dossanov, A; Drugakov, V; Fourletova, J; Geiser, A; Gladkov, D; Göttlicher, P; Grebenyuk, J; Gregor, I; Haas, T; Hain, W; Horn, C; Huttmann, A; Kahle, B; Katkov, I I; Klein, U; Kötz, U; Kowalski, H; Lobodzinska, E; Löhr, B; Mankel, R; Melzer-Pellmann, I A; Miglioranzi, S; Montanari, A; Notz, D; Rinaldi, L; Roloff, P; Rubinsky, I; Santamarta, R; Schneekloth, U; Spiridonov, A; Stadie, H; Szuba, D; Szuba, J; Theedt, T; Wolf, G; Wrona, K; Youngman, C; Zeuner, W; Lohmann, W; Schlenstedt, S; Barbagli, G; Gallo, E; Pelfer, P G; Bamberger, A; Dobur, D; Karstens, F; Vlasov, N N; Bussey, P J; Doyle, A T; Dunne, W; Ferrando, J; Forrest, M; Saxon, D H; Skillicorn, I O; Gialas, I; Papageorgiu, K; Gosau, T; Holm, U; Klanner, R; Lohrmann, E; Salehi, H; Schleper, P; Schörner-Sadenius, T; Sztuk, J; Wichmann, K; Wick, K; Foudas, C; Fry, C; Long, K R; Tapper, A D; Kataoka, M; Matsumoto, T; Nagano, K; Tokushuku, K; Yamada, S; Yamazaki, Y; Barakbaev, A N; Boos, E G; Pokrovskiy, N S; Zhautykov, B O; Aushev, V; Son, D; De Favereau, J; Piotrzkowski, K; Barreiro, F; Glasman, C; Jiménez, M; Labarga, L; Del Peso, J; Ron, E; Soares, M; Terron, J; Zambrana, M; Corriveau, F; Liu, C; Walsh, R; Zhou, C; Tsurugai, T; Antonov, A; Dolgoshein, B A; Sosnovtsev, V; Stifutkin, A; Suchkov, S; Dementiev, R K; Ermolov, P F; Gladilin, L K; Khein, L A; Korzhavina, I A; Kuzmin, V A; Levchenko, B B; Lukina, O Yu; Proskuryakov, A S; Shcheglova, L M; Zotkin, D S; Zotkin, S A; Abt, I; Büttner, C; Caldwell, A; Kollar, D; Schmidke, W B; Sutiak, J; Grigorescu, G; Keramidas, A; Koffeman, E; Kooijman, P; Pellegrino, A; Tiecke, H; Vázquez, M; Wiggers, L; Brümmer, N; Bylsma, B; Durkin, L S; Lee, A; Ling, T Y; Allfrey, P D; Bell, M A; Cooper-Sarkar, A M; Cottrell, A; Devenish, R C E; Foster, B; Korcsak-Gorzo, K; Patel, S; Roberfroid, V; Robertson, A; Straub, P B; Uribe-, C; Estrada; Walczak, R; Bellan, P; Bertolin, A; Brugnera, R; Carlin, R; Dal Corso, F; Dusini, S; Garfagnini, A; Limentani, S; Longhin, A; Stanco, L; Turcato, M; Oh, B Y; Raval, A; Ukleja, J; Whitmore, J J; Iga, Y; D'Agostini, G; Marini, G; Nigro, A; Cole, J E; Hart, J C; Abramowicz, H; Gabareen, A; Ingbir, R; Kananov, S; Levy, A; Kuze, M; Maeda, J; Hori, R; Kagawa, S; Okazaki, N; Shimizu, S; Tawara, T; Hamatsu, R; Kaji, H; Kitamura, S; Ota, O; Ri, Y D; Ferrero, M I; Monaco, V; Sacchi, R; Solano, A; Arneodo, M; Ruspa, M; Fourletov, S; Martin, J F; Boutle, S K; Butterworth, J M; Gwenlan, C; Jones, T W; Loizides, J H; Sutton, M R; Wing, M; Brzozowska, B; Ciborowski, J; Grzelak, G; Kulinski, P; Luzniak, P; Malka, J; Nowak, R J; Pawlak, J M; Tymieniecka, T; Ukleja, A; Zarnecki, A F; Adamus, M; Plucinsky, P P; Eisenberg, Y; Giller, I; Hochman, D; Karshon, U; Rosin, M; Brownson, E; Danielson, T; Everett, A; Kcira, D; Reeder, D D; Ryan, P; Savin, A A; Smith, W H; Wolfe, H; Bhadra, S; Catterall, C D; Cui, Y; Hartner, G; Menary, S; Noor, U; Standage, J; Whyte, J

2007-01-01

203

In-season root-zone N management for mitigating greenhouse gas emission and reactive N losses in intensive wheat production.  

PubMed

Although both the grain yields and environmental costs of nitrogen (N) fertilization are gaining more public and scientific debate, the complex linkages among crop productivity, N application rate, environmental footprints, and the consequences of improved N management are not well understood. We considered the concept of linking greenhouse gas (GHG) emission, reactive N losses, and N fertilizer application rates with crop productivity to determine the response of the GHG emission and reactive N losses to N surplus and further evaluated the potential to reduce these N environmental footprints by in-season root-zone N management. A meta-analysis suggested an exponential increase in the response of direct N2O emissions and nitrate leaching to an increasing N surplus, while NH3 volatilization increased linearly with an increasing N application rate for intensive wheat production in north China. The GHG emission and reactive N losses during N fertilizer application increased exponentially with an increasing N surplus. By pooling all 121 on-farm experimental sites, an in-season root-zone N management strategy was shown to reduce the N application rate by 61% from 325 kg N ha(-1) to 128 kg N ha(-1) compared to the farmers' N practice, with no loss in wheat grain yield. As a result, the intensity of GHG emission and reactive N losses were reduced by 77% and 80%, respectively. The intensity of GHG emission and reactive N losses can be further reduced due to the improved N recovery and increased grain yield achieved by best crop management. In conclusion, N recovery efficiency and yield improvements should be used to reduce future agricultural N environmental footprints, rather than reducing the N application rate. PMID:23662999

Cui, Zhenling; Yue, Shanchao; Wang, Guiliang; Zhang, Fusuo; Chen, Xinping

2013-06-01

204

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

PubMed

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 5-10nm, specific surface area of 210±10m(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 72h EC50 values of nano-TiO2 to K. brevis and S. costatum were 10.69 and 7.37mgL(-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

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

2015-01-01

205

Quantum time evolution in time-dependent fields and time-independent reactive-scattering calculations via an efficient Fourier grid preconditioner  

E-print Network

Quantum time evolution in time-dependent fields and time-independent reactive is suggested for accurate large-scale quantum dynamics simulations. The time-dependent Schro¨dinger equation with finite time-dependent interaction terms is replaced by an inhomogeneous equation with imaginary boundary

Miller, William H.

206

Inhibition of biphasic ethylene production enhances tolerance to abiotic stress by reducing the accumulation of reactive oxygen species in Nicotiana tabacum  

Microsoft Academic Search

Reactive oxygen species (ROS), such as H2O2, are important plant cell signaling molecules involved in responses to biotic and abiotic stresses and in developmental and\\u000a physiological processes. Despite the well-known physiological functions of ethylene production and stress signaling via ROS\\u000a during stresses, whether ethylene acts alone or in conjunction with ROS has not yet been fully elucidated. Therefore, we investigated

Soo Jin Wi; Su Jin Jang; Ky Young Park

2010-01-01

207

Nitrofurantoin-Stimulated Reactive Oxygen Species Production and Genotoxicity in Digestive Gland Microsomes and Cytosol of the Common Mussel ( Mytilus edulis L.)  

Microsoft Academic Search

The ability of nitrofurantoin (NF) to produce reactive oxygen species (ROS) was investigated in subcellular fractions of digestive gland of the mussel Mytilus edulis in terms of oxygen consumption and the formation of superoxide anion radical (O?2) (measured as SOD-sensitive cytochrome c reduction or SOD-sensitive .OH production), H2O2 (effects of catalase), and hydroxyl radical (.OH) (iron\\/EDTA-mediated oxidation of KMBA to

P. G. Martinez; G. W. Winston; C. Metashdickey; S. C. M. Ohara; D. R. Livingstone

1995-01-01

208

Pair production of quarkonia and electroweak bosons from double-parton scatterings in nuclear collisions at the LHC  

E-print Network

Cross sections for the concurrent production of pairs of quarkonia (J/psi, Upsilon) and/or gauge bosons (W, Z) from double-parton scatterings (DPS) in high-energy proton-nucleus and nucleus-nucleus collisions at the LHC are calculated. The estimates are based on next-to-leading-order perturbative QCD predictions, including nuclear modifications of the parton densities, for the corresponding single-scattering cross sections. Expected event rates for J/psi+J/psi, J/psi+Upsilon, J/psi+W, J/psi+Z, Upsilon+Upsilon, Upsilon+W, Upsilon+Z, and same-sign W+W production in their (di)leptonic decay modes, after typical acceptance and efficiency losses, are given for pPb and PbPb collisions.

David d'Enterria; Alexander M. Snigirev

2014-08-21

209

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

210

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

NASA Astrophysics Data System (ADS)

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.

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

1985-11-01

211

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

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

212

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

213

Fracture Reactivation in Chemically Reactive Rock Systems  

NASA Astrophysics Data System (ADS)

Reactivation of existing fractures is a fundamental process of brittle failure that controls the nucleation of earthquake ruptures, propagation and linkage of hydraulic fractures in oil and gas production, and the evolution of fault and fracture networks and thus of fluid and heat transport in the upper crust. At depths below 2-3 km, and frequently shallower, brittle processes of fracture growth, linkage, and reactivation compete with chemical processes of fracture sealing by mineral precipitation, with precipitation rates similar to fracture opening rates. We recently found rates of fracture opening in tectonically quiescent settings of 10-20 ?m/m.y., rates similar to euhedral quartz precipitation under these conditions. The tendency of existing partially or completely cemented fractures to reactivate will vary depending on strain rate, mineral precipitation kinetics, strength contrast between host rock and fracture cement, stress conditions, degree of fracture infill, and fracture network geometry. Natural fractures in quartzite of the Cambrian Eriboll Formation, NW Scotland, exhibit a complex history of fracture formation and reactivation, with reactivation involving both repeated crack-seal opening-mode failure and shear failure of fractures that formed in opening mode. Fractures are partially to completely sealed with crack-seal or euhedral quartz cement or quartz cement fragmented by shear reactivation. Degree of cementation controls the tendency of fractures for later shear reactivation, to interact elastically with adjacent open fractures, and their intersection behavior. Using kinematic, dynamic, and diagenetic criteria, we determine the sequence of opening-mode fracture formation and later shear reactivation. We find that sheared fracture systems of similar orientation display spatially varying sense of slip We attribute these inconsistent directions of shear reactivation to 1) a heterogeneous stress field in this highly fractured rock unit and 2) variations in the degree of fracture cement infill in fractures of same orientation, allowing fractures to reactivate at times when adjacent, more cemented fractures remain dormant. The observed interaction of chemical and mechanical fracture growth and sealing processes in this chemically reactive and heavily deformed rock unit results in a complex fracture network geometry not generally observed in less chemically reactive, shallower crustal environments.

Eichhubl, P.; Hooker, J. N.

2013-12-01

214

Aging Enhances Production of Reactive Oxygen Species and Bactericidal Activity in Peritoneal Macrophages by Up-Regulating Classical Activation Pathways  

PubMed Central

Maintenance of macrophages in their basal state and their rapid activation in response to pathogen detection is 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 mo) and aged (14–15 mo) Balb/c mice. In agreement with prior suggestions, we observe age-dependent increases in macrophage recruitment 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 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 proteins linked to immune cell pathways under both basal conditions and following LPS activation. Immune pathways up-regulated in macrophages isolated from aged mice include proteins critical to formation of the immunoproteasome. Detection of these latter proteins are 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 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 pre-activated state that enhances their sensitivities of LPS exposure. The hyper-responsive activation of macrophages in aged animals may act to minimize infection to general bacterial threats that arise due to age-dependent declines in adaptive immunity. However, this hypersensitivity and the associated increase in the formation of reactive oxygen species is likely to contribute to observed age-dependent increases in oxidative damage that underlie many diseases of the elderly. PMID:21981794

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

2011-01-01

215

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

SciTech Connect

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.

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

2011-10-07

216

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

PubMed

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

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

2013-07-01

217

Endogenous Ig production in mu transgenic mice. II. Anti-Ig reactivity and apparent double allotype expression.  

PubMed

In 17.2.25 mu transgenic mice (M54, M95), many of the expressed Ig, whether encoded by the transgene or endogenous H chain genes, react with Ig. IgM antibodies encoded by the 17.2.25 mu transgene transfected into J558L myeloma cells are also Ig reactive. In addition, anti-Ig reactivity was manifested by antibodies of the IgM, IgG, and IgA isotypes from the transgenic mice, suggesting that this characteristic reactivity is associated with VH and VL domains of these antibodies. These antibodies bind the (Fab')2 fragment of mouse IgG1 mAb known to be directed against C mu allotypic determinants. This finding could account for the so called "double producer" B cells found in mu transgenic mice and previously identified in serologic assays conducted with two different anti-mu allotypic reagents. In transgenic mice, a high frequency of the antibodies encoded by the transgene or endogenous H chain genes react with polyclonal and monoclonal antiidiotypic antibodies raised against the 17.2.25 Id. The idiotypic and/or antiidiotypic reactivity displayed by antibodies derived from these transgenic mice is similar to that of antibodies expressed by neonatal B cells of normal mice. Thus, our data suggest that transgene expression can play an important role in shaping the endogenous repertoire of antibody specificities. PMID:8468474

Imanishi-Kari, T; Huang, C A; Iacomini, J; Yannoutsos, N

1993-04-15

218

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

NASA Technical Reports Server (NTRS)

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.

Robertson, S. J.

1976-01-01

219

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

PubMed Central

The interferon (IFN)-? 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-? 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-? 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-? 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-? assays to identify individuals with this condition. PMID:25494469

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

220

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

PubMed

The interferon (IFN)-? 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-? 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-? 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-? 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-? assays to identify individuals with this condition. PMID:25494469

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

2014-12-01

221

Pion and Nucleon Propagators in Finite Nuclei with Applications in Pion Scattering, Pion Production, and Pion-Nucleon Interactions  

NASA Astrophysics Data System (ADS)

We present a theory for interacting pions and nucleons based on relativistic quantum field theory and expressed as coupled integral equations among the single -particle propagators and the vertex. We show that, in the "local" approximation (which is very convenient but unfortunately violates crossing symmetry), these equations are only slightly more complicated than the Boltzmann equation, and therefore should be computationally feasible. In the more restrictive Migdal approximation we evaluate the pion propagator explicitly using a mean field model for the nucleons and show applications to low energy pion scattering from nuclei and "subthreshold" pion production. It is found, in agreement with pion optical potential results, that 40 Mev pions scatter primarily from the nuclear surface and are extremely sensitive to the density distribution in this region. We present a solution to the general problem of relativistic particle production from a spatially, temporally, and energetically finite source and en route, obtain a theorem concerning the angular distribution of the emitted particles; quantitative calculations for pion production are not yet completed. The applications we consider involve only pions, nucleons, and (DELTA)'s and are basically time independent models, however the generalization to include the higher mass mesons is straight-forward and the general equations are completely time-dependent. This theory, therefore, should contain a complete description of transport theory including fluctuations as well as mean properties.

White, Gary Dane

222

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

PubMed Central

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

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

2008-01-01

223

Forward-jet production in deep inelastic ep scattering at HERA  

Microsoft Academic Search

Forward jet cross sections have been measured in neutral current deep inelastic scattering at low Bjorken-x with the ZEUS\\u000a detector at HERA using an integrated luminosity of 81.8 pb-1. Measurements are presented for inclusive forward jets as well as for forward jets accompanied by a dijet system. The explored\\u000a phase space, with jet pseudorapidity up to 4.3 is expected to be

S. Chekanov; M. Derrick; S. Magill; B. Musgrave; D. Nicholass; J. Repond; R. Yoshida; M. C. K. Mattingly; M. Jechow; N. Pavel; A. G. Yagües Molina; S. Antonelli; P. Antonioli; G. Bari; M. Basile; L. Bellagamba; M. Bindi; D. Boscherini; A. Bruni; G. Bruni; L. Cifarelli; F. Cindolo; A. Contin; M. Corradi; S. De Pasquale; G. Iacobucci; A. Margotti; R. Nania; A. Polini; G. Sartorelli; A. Zichichi; D. Bartsch; I. Brock; H. Hartmann; E. Hilger; H.-P. Jakob; M. Jüngst; O. M. Kind; A. E. Nuncio-Quiroz; E. Paul; R. Renner; U. Samson; V. Schönberg; R. Shehzadi; M. Wlasenko; N. H. Brook; G. P. Heath; J. D. Morris; M. Capua; S. Fazio; A. Mastroberardino; M. Schioppa; G. Susinno; E. Tassi; J. Y. Kim; K. J. Ma; Z. A. Ibrahim; B. Kamaluddin; W. A. T. Wan Abdullah; Y. Ning; Z. Ren; F. Sciulli; J. Chwastowski; A. Eskreys; J. Figiel; A. Galas; M. Gil; K. Olkiewicz; P. Stopa; L. Zawiejski; L. Adamczyk; T. Bold; I. Grabowska-Bo?d; D. Kisielewska; J. ?ukasik; M. Przybycien; L. Suszycki; A. Kotanski; W. Slominski; V. Adler; U. Behrens; I. Bloch; C. Blohm; A. Bonato; K. Borras; R. Ciesielski; N. Coppola; A. Dossanov; V. Drugakov; J. Fourletova; A. Geiser; D. Gladkov; P. Göttlicher; J. Grebenyuk; I. Gregor; T. Haas; W. Hain; C. Horn; A. Hüttmann; B. Kahle; I. I. Katkov; U. Klein; U. Kötz; H. Kowalski; E. Lobodzinska; B. Löhr; R. Mankel; I.-A. Melzer-Pellmann; S. Miglioranzi; A. Montanari; T. Namsoo; D. Notz; L. Rinaldi; P. Roloff; I. Rubinsky; R. Santamarta; U. Schneekloth; A. Spiridonov; H. Stadie; D. Szuba; J. Szuba; T. Theedt; G. Wolf; K. Wrona; C. Youngman; W. Zeuner; W. Lohmann; S. Schlenstedt; G. Barbagli; E. Gallo; P. G. Pelfer; A. Bamberger; D. Dobur; F. Karstens; N. N. Vlasov; P. J. Bussey; A. T. Doyle; W. Dunne; M. Forrest; D. H. Saxon; I. O. Skillicorn; I. Gialas; K. Papageorgiu; T. Gosau; U. Holm; R. Klanner; E. Lohrmann; H. Salehi; P. Schleper; T. Schörner-Sadenius; J. Sztuk; K. Wichmann; K. Wick; C. Foudas; C. Fry; K. R. Long; A. D. Tapper; M. Kataoka; T. Matsumoto; K. Nagano; K. Tokushuku; S. Yamada; Y. Yamazaki; A. N. Barakbaev; E. G. Boos; N. S. Pokrovskiy; B. O. Zhautykov; V. Aushev; M. Borodin; A. Kozulia; M. Lisovyi; D. Son; J. de Favereau; K. Piotrzkowski; F. Barreiro; C. Glasman; M. Jimenez; L. Labarga; J. del Peso; E. Ron; M. Soares; J. Terrón; M. Zambrana; F. Corriveau; C. Liu; R. Walsh; C. Zhou; T. Tsurugai; A. Antonov; B. A. Dolgoshein; V. Sosnovtsev; A. Stifutkin; S. Suchkov; R. K. Dementiev; P. F. Ermolov; L. K. Gladilin; L. A. Khein; I. A. Korzhavina; V. A. Kuzmin; B. B. Levchenko; O. Yu. Lukina; A. S. Proskuryakov; L. M. Shcheglova; D. S. Zotkin; S. A. Zotkin; I. Abt; C. Büttner; A. Caldwell; D. Kollar; W. B. Schmidke; J. Sutiak; G. Grigorescu; A. Keramidas; E. Koffeman; P. Kooijman; A. Pellegrino; H. Tiecke; M. Vázquez; L. Wiggers; N. Brümmer; B. Bylsma; L. S. Durkin; A. Lee; T. Y. Ling; P. D. Allfrey; M. A. Bell; A. M. Cooper-Sarkar; R. C. E. Devenish; J. Ferrando; B. Foster; K. Korcsak-Gorzo; K. Oliver; S. Patel; V. Roberfroid; A. Robertson; P. B. Straub; C. Uribe-Estrada; R. Walczak; P. Bellan; A. Bertolin; R. Brugnera; R. Carlin; F. Dal Corso; S. Dusini; A. Garfagnini; S. Limentani; A. Longhin; L. Stanco; M. Turcato; B. Y. Oh; A. Raval; J. Ukleja; J. J. Whitmore; Y. Iga; G. D’Agostini; G. Marini; A. Nigro; J. E. Cole; J. C. Hart; H. Abramowicz; A. Gabareen; R. Ingbir; S. Kananov; A. Levy; M. Kuze; J. Maeda; R. Hori; S. Kagawa; N. Okazaki; S. Shimizu; T. Tawara; R. Hamatsu; H. Kaji; S. Kitamura; O. Ota; Y. D. Ri; M. I. Ferrero; V. Monaco; R. Sacchi; A. Solano; M. Arneodo; M. Ruspa; S. Fourletov; J. F. Martin; S. K. Boutle; J. M. Butterworth; C. Gwenlan; T. W. Jones; J. H. Loizides; M. R. Sutton; M. Wing; B. Brzozowska; J. Ciborowski; G. Grzelak; P. Kulinski; P. ?u?niak; J. Malka; R. J. Nowak; J. M. Pawlak; T. Tymieniecka; A. Ukleja; A. F. ?arnecki; M. Adamus; P. Plucinski; Y. Eisenberg; I. Giller; D. Hochman; U. Karshon; M. Rosin; E. Brownson; T. Danielson; A. Everett; D. Kçira; D. D. Reeder; P. Ryan; A. A. Savin; W. H. Smith; H. Wolfe; S. Bhadra; C. D. Catterall; Y. Cui; G. Hartner; S. Menary; U. Noor; J. Standage; J. Whyte

2007-01-01

224

Forward jet production in deep inelastic ep scattering and low- x parton dynamics at HERA  

Microsoft Academic Search

Differential inclusive jet cross sections in neutral current deep inelastic ep scattering have been measured with the ZEUS detector using an integrated luminosity of 38.7 pb?1. The jets have been identified using the kT cluster algorithm in the longitudinally invariant inclusive mode in the laboratory frame; they have been selected with jet transverse energy, ETjet above 6 GeV and jet

S. Chekanov; M. Derrick; S. Magill; S. Miglioranzi; B. Musgrave; J. Repond; R. Yoshida; M. C. K. Mattingly; N. Pavel; A. G. Yagües Molina; P. Antonioli; G. Bari; M. Basile; L. Bellagamba; D. Boscherini; A. Bruni; G. Bruni; G. Cara Romeo; L. Cifarelli; F. Cindolo; A. Contin; M. Corradi; S. De Pasquale; P. Giusti; G. Iacobucci; A. Margotti; A. Montanari; R. Nania; F. Palmonari; A. Pesci; A. Polini; L. Rinaldi; G. Sartorelli; A. Zichichi; G. Aghuzumtsyan; D. Bartsch; I. Brock; S. Goers; H. Hartmann; E. Hilger; P. Irrgang; H.-P. Jakob; O. Kind; U. Meyer; E. Paul; J. Rautenberg; R. Renner; K. C. Voss; M. Wang; M. Wlasenko; D. S. Bailey; N. H. Brook; J. E. Cole; G. P. Heath; T. Namsoo; S. Robins; M. Capua; A. Mastroberardino; M. Schioppa; G. Susinno; E. Tassi; J. Y. Kim; K. J. Ma; M. Helbich; Y. Ning; Z. Ren; W. B. Schmidke; F. Sciulli; J. Chwastowski; A. Eskreys; J. Figiel; A. Galas; K. Olkiewicz; P. Stopa; D. Szuba; L. Zawiejski; L. Adamczyk; T. Bo?d; I. Grabowska-Bo?d; D. Kisielewska; A. M. Kowal; J. ?ukasik; M. Przybycie?; L. Suszycki; J. Szuba; A. Kota?ski; W. S?omi?ski; V. Adler; U. Behrens; I. Bloch; K. Borras; G. Drews; J. Fourletova; A. Geiser; D. Gladkov; P. Göttlicher; O. Gutsche; T. Haas; W. Hain; C. Horn; B. Kahle; U. Kötz; H. Kowalski; G. Kramberger; D. Lelas; H. Lim; B. Löhr; R. Mankel; I.-A. Melzer-Pellmann; C. N. Nguyen; D. Notz; A. E. Nuncio-Quiroz; A. Raval; R. Santamarta; U. Schneekloth; G. Wolf; C. Youngman; W. Zeuner; S. Schlenstedt; G. Barbagli; E. Gallo; C. Genta; P. G. Pelfer; A. Bamberger; A. Bamberger; F. Karstens; D. Dobur; N. N. Vlasov; P. J. Bussey; A. T. Doyle; J. Ferrando; S. Hanlon; D. H. Saxon; I. O. Skillicorn; I. Gialas; T. Carli; T. Gosau; U. Holm; N. Krumnack; E. Lohrmann; M. Milite; H. Salehi; P. Schleper; T. Schörner-Sadenius; S. Stonjek; K. Wichmann; A. Ziegler; C. Collins-Tooth; C. Foudas; R. Gonçalo; K. R. Long; A. D. Tapper; M. Kataoka; K. Nagano; K. Tokushuku; S. Yamada; Y. Yamazaki; A. N. Barakbaev; E. G. Boos; N. S. Pokrovskiy; B. O. Zhautykov; D. Son; J. de Favereau; K. Piotrzkowski; F. Barreiro; C. Glasman; O. González; M. Jimenez; L. Labarga; J. del Peso; J. Terrón; M. Zambrana; M. Barbi; F. Corriveau; C. Liu; S. Padhi; M. Plamondon; D. G. Stairs; R. Walsh; C. Zhou; T. Tsurugai; A. Antonov; P. Danilov; B. A. Dolgoshein; V. Sosnovtsev; A. Stifutkin; S. Suchkov; R. K. Dementiev; P. F. Ermolov; L. K. Gladilin; I. I. Katkov; L. A. Khein; I. A. Korzhavina; V. A. Kuzmin; B. B. Levchenko; O. Yu. Lukina; A. S. Proskuryakov; L. M. Shcheglova; D. S. Zotkin; I. Abt; C. Büttner; A. Caldwell; X. Liu; J. Sutiak; N. Coppola; G. Grigorescu; S. Grijpink; A. Keramidas; E. Koffeman; P. Kooijman; E. Maddox; A. Pellegrino; S. Schagen; H. Tiecke; M. Vázquez; L. Wiggers; E. de Wolf; N. Brümmer; B. Bylsma; L. S. Durkin; T. Y. Ling; P. D. Allfrey; M. A. Bell; A. M. Cooper; A. Cottrell; R. C. E. Devenish; B. Foster; G. Grzelak; C. Gwenlan; T. Kohno; S. Patel; P. B. Straub; R. Walczak; P. Bellan; A. Bertolin; R. Brugnera; R. Carlin; R. Ciesielski; F. Dal Corso; S. Dusini; A. Garfagnini; S. Limentani; A. Longhin; L. Stanco; M. Turcato; E. A. Heaphy; F. Metlica; B. Y. Oh; J. J. Whitmore; Y. Iga; G. D'Agostini; G. Marini; A. Nigro; J. C. Hart; H. Abramowicz; A. Gabareen; S. Kananov; A. Kreisel; A. Levy; M. Kuze; S. Kagawa; T. Tawara; R. Hamatsu; H. Kaji; S. Kitamura; K. Matsuzawa; O. Ota; Y. D. Ri; M. Costa; M. I. Ferrero; V. Monaco; R. Sacchi; A. Solano; M. Arneodo; M. Ruspa; S. Fourletov; T. Koop; J. F. Martin; A. Mirea; J. M. Butterworth; R. Hall-Wilton; T. W. Jones; J. H. Loizides; M. R. Sutton; C. Targett-Adams; M. Wing; J. Ciborowski; P. Kulinski; P. ?u?niak; J. Malka; R. J. Nowak; J. M. Pawlak; J. Sztuk; T. Tymieniecka; A. Tyszkiewicz; A. Ukleja; J. Ukleja; A. F. ?arnecki; M. Adamus; P. Plucinski; Y. Eisenberg; D. Hochman; U. Karshon; M. S. Lightwood; A. Everett; D. Kçira; S. Lammers; L. Li; D. D. Reeder; M. Rosin; P. Ryan; A. A. Savin; W. H. Smith; S. Dhawan; S. Bhadra; C. D. Catterall; Y. Cui; G. Hartner; S. Menary; U. Noor; M. Soares; J. Standage; J. Whyte

2006-01-01

225

Measurement of Dijet Production in Diffractive Deep-Inelastic ep Scattering at HERA  

E-print Network

A measurement is presented of single- and double-differential dijet cross sections in diffractive deep-inelastic $ep$ scattering at HERA using data collected by the H1 experiment corresponding to an integrated luminosity of 290 pb^{-1}. The investigated phase space is spanned by the photon virtuality in the range of 4fractional proton longitudinal momentum loss x_pomorder QCD predictions based on diffractive parton distribution functions and the value of the strong coupling constant is extracted.

H1 Collaboration

2014-12-03

226

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

NASA Astrophysics Data System (ADS)

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

Detyothin, Sukeewan

227

Observation by flow sup 1 H NMR and dimerization kinetics and products of reactive ortho-quinodimethanes and benzocyclobutadiene  

SciTech Connect

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.

Fischer, D.

1990-09-21

228

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

SciTech Connect

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

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

2006-12-15

229

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

PubMed

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(2)(-) 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(2)(-). 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. PMID:22005465

Kobashigawa, Shinko; Suzuki, Keiji; Yamashita, Shunichi

2011-11-01

230

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

Microsoft Academic Search

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

Imran Khalid; Amanda M Godfrey; Daniel R Ouellette

2009-01-01

231

Forward-jet production in deep inelastic ep scattering at HERA  

E-print Network

Forward jet cross sections have been measured in neutral current deep inelastic scattering at low Bjorken-x with the ZEUS detector at HERA using an integrated luminosity of ${81.8 \\rm pb}^{-1}$. Measurements are presented for inclusive forward jets as well as for forward jets accompanied by a dijet system. The explored phase space, with jet pseudorapidity up to 4.3 is expected to be particularly sensitive to the dynamics of QCD parton evolution at low x. The measurements are compared to fixed-order QCD calculations and to leading-order parton-shower Monte Carlo models.

Chekanov, S; Magill, S; Musgrave, B; Nicholass, D; Repond, J; Yoshida, R; Mattingly, M C K; Jechow, USAM; Pavel, N; Yagues-Molina, A G; Antonelli, S; Antonioli, P; Bari, G; Basile, M; Bellagamba, L; Bindi, M; Boscherini, D; Bruni, A; Bruni, G; Cifarelli, L; Cindolo, F; Contin, A; Corradi, M; De Pasquale, S; Iacobucci, G; Margotti, A; Nania, R; Polini, A; Sartorelli, G; Zichichi, A; Bartsch, D; Brock, I; Hartmann, H; Hilger, E; Jakob, H P; Jüngst, M; Kind, O M; Nuncio-Quiroz, A E; Paul, E; Renner, R; Samson, U; Schonberg, V; Shehzadi, R; Wlasenko, M; Brook, N H; Heath, G P; Morris, J D; Capua, M; Fazio, S; Mastroberardino, A; Schioppa, M; Susinno, G; Tassi, E; Kim, J Y; Ma, K J; Ibrahim, Z A; Kamaluddin, B; Wan-Abdullah, W A T; Ning, Y; Ren, Z; Sciulli, F; Chwastowski, J; Eskreys, A; Figiel, J; Galas, A; Gil, M; Olkiewicz, K; Stopa, P; Zawiejski, L; Adamczyk, L; Bold, T; Grabowska-Bold, I; Kisielewska, D; Lukasik, J; Przybycien, M; Suszycki, L; Kotanski, A; Slominski, W; Adler, V; Behrens, U; Bloch, I; Blohm, C; Bonato, A; Borras, K; Ciesielski, R; Coppola, N; Dossanov, A; Drugakov, V; Fourletova, J; Geiser, A; Gladkov, D; Göttlicher, P; Grebenyuk, J; Gregor, I; Haas, T; Hain, W; Horn, C; Huttmann, A; Kahle, B; Katkov, I I; Klein, U; Kötz, U; Kowalski, H; Lobodzinska, E; Löhr, B; Mankel, R; Melzer--, I A; Pellmann; Miglioranzi, S; Montanari, A; Namsoo, T; Notz, D; Rinaldi, L; Roloff, P; Rubinsky, I; Santamarta, R; Schneekloth, U; Spiridonov, A; Stadie, H; Szuba, D; Szuba, J; Theedt, T; Wolf, G; Wrona, K; Youngman, C; Zeuner, W; Lohmann, W; Schlenstedt, S; Barbagli, G; Gallo, E; Pelfer, P G; Bamberger, A; Dobur, D; Karstens, F; Vlasov, N N; Bussey, P J; Doyle, A T; Dunne, W; Forrest, M; Saxon, D H; Skillicorn, I O; Gialas, I; Papageorgiu, K; Gosau, T; Holm, U; Klanner, R; Lohrmann, E; Salehi, H; Schleper, P; Schörner-Sadenius, T; Sztuk, J; Wichmann, K; Wick, K; Foudas, C; Fry, C; Long, K R; Tapper, A D; Kataoka, M; Matsumoto, T; Nagano, K; Tokushuku, K; Yamada, S; Yamazaki, Y; Barakbaev, A N; Boos, E G; Pokrovskiy, N S; Zhautykov, B O; Aushev, V; Borodin, M; Kozulia, A; Lisovyi, M; Son, D; De Favereau, J; Piotrzkowski, K; Barreiro, F; Glasman, C; Jiménez, M; Labarga, L; Del Peso, J; Ron, E; Soares, M; Terron, J; Zambrana, M; Corriveau, F; Liu, C; Walsh, R; Zhou, C; Tsurugai, T; Antonov, A; Dolgoshein, B A; Sosnovtsev, V; Stifutkin, A; Suchkov, S; Dementiev, R K; Ermolov, P F; Gladilin, L K; Khein, L A; Korzhavina, I A; Kuzmin, V A; Levchenko, B B; Lukina, O Yu; Proskuryakov, A S; Shcheglova, L M; Zotkin, D S; Zotkin, S A; Abt, I; Büttner, C; Caldwell, A; Kollar, D; Schmidke, W B; Sutiak, J; Grigorescu, G; Keramidas, A; Koffeman, E; Kooijman, P; Pellegrino, A; Tiecke, H; Vázquez, M; Wiggers, L; Brümmer, N; Bylsma, B; Durkin, L S; Lee, A; Ling, T Y; Allfrey, P D; Bell, M A; Cooper-Sarkar, A M; Devenish, R C E; Ferrando, J; Fos-ter, B; Korcsak-Gorzo, K; Oliver, K; Patel, S; Roberfroid, V; Robertson, A; Straub, P B; Uribe-Estrada, C; Walczak, R; Bellan, P; Bertolin, A; Brugnera, R; Carlin, R; Dal Corso, F; Dusini, S; Garfagnini, A; Limentani, S; Longhin, A; Stanco, L; Turcato, M; Oh, B Y; Raval, A; Ukleja, J; Whitmore, J J; Iga, Y; D'Agostini, G; Marini, G; Nigro, A; Cole, J E; Hart, J C; Abramowicz, H; Gabareen, A; Ingbir, R; Kananov, S; Levy, A; Kuze, M; Maeda, J; Hori, R; Kagawa, S; Okazaki, N; Shimizu, S; Tawara, T; Hamatsu, R; Kaji, H; Kitamura, S; Ota, O; Ri, Y D; Ferrero, M I; Monaco, V; Sacchi, R; Solano, A; Arneodo, M; Ruspa, M; Fourletov, S; Martin, J F; Boutle, S K; Butterworth, J M; Gwenlan, C; Jones, T W; Loizides, J H; Sutton, M R; Wing, M; Brzozowska, B; Ciborowski, J; Grzelak, G; Kulinski, P; Luzniak, P; Malka, J; Nowak, R J; Pawlak, J M; Tymieniecka, T; Ukleja, A; Zarnecki, A F; Adamus, M; Plucinsky, P P; Eisenberg, Y; Giller, I; Hochman, D; Karshon, U; Rosin, M; Brownson, E; Danielson, T; Everett, A; Kcira, D; Reeder, D D; Ryan, P; Savin, A A; Smith, W H; Wolfe, H; Bhadra, S; Catterall, C D; Cui, Y; Hartner, G; Menary, S; Noor, U; Standage, J; Whyte, J

2007-01-01

232

Nitric oxide production occurs downstream of reactive oxygen species in guard cells during stomatal closure induced by chitosan in abaxial epidermis of Pisum sativum.  

PubMed

The effects of chitosan (beta-1,4 linked glucosamine, a fungal elicitor), on the patterns of stomatal movement and signaling components were studied. cPTIO (NO scavenger), sodium tungstate (nitrate reductase inhibitor) or L: -NAME (NO synthase inhibitor) restricted the chitosan induced stomatal closure, demonstrating that NO is an essential factor. Similarly, catalase (H(2)O(2) scavenger) or DPI [NAD(P)H oxidase inhibitor] and BAPTA-AM or BAPTA (calcium chelators) prevented chitosan induced stomatal closure, suggesting that reactive oxygen species (ROS) and calcium were involved during such response. Monitoring the NO and ROS production in guard cells by fluorescent probes (DAF-2DA and H(2)DCFDA) indicated that on exposure to chitosan, the levels of NO rose after only 10 min, while those of ROS increased already by 5 min. cPTIO or sodium tungstate or L: -NAME prevented the rise in NO levels but did not restrict the ROS production. In contrast, catalase or DPI restricted the chitosan-induced production of both ROS and NO in guard cells. The calcium chelators, BAPTA-AM or BAPTA, did not have a significant effect on the chitosan induced rise in NO or ROS. We propose that the production of NO is an important signaling component and participates downstream of ROS production. The effects of chitosan strike a marked similarity with those of ABA or MJ on guard cells and indicate the convergence of their signal transduction pathways leading to stomatal closure. PMID:19084995

Srivastava, Nupur; Gonugunta, Vijay K; Puli, Mallikarjuna R; Raghavendra, Agepati S

2009-03-01

233

Working Memory and Reactivity  

ERIC Educational Resources Information Center

The present study explores the relationship between working memory capacity (WMC) and think-alouds, focusing on the issue of reactivity. Two WM span tasks (listening span and operation span) were administered to 42 English-speaking learners of Spanish. Learner performance on reading comprehension and written production was measured under two…

Goo, Jaemyung

2010-01-01

234

Impulsive model for reactive collisions  

NASA Technical Reports Server (NTRS)

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.

Marron, M. T.; Bernstein, R. B.

1972-01-01

235

Mountain cedar pollen induces IgE-independent mast cell degranulation, IL-4 production, and intracellular reactive oxygen species generation  

PubMed Central

Cedar pollens cause severe allergic disease throughout the world. We have previously characterized allergenic pollen glycoproteins from mountain cedar (Juniperus ashei) that bind to allergen-specific immunoglobulin E (IgE). In the present report, we investigated an alternative pathway of mast cell activation by mountain cedar pollen extract through IgE-independent mechanisms. We show that mountain cedar pollen directly induces mast cell serotonin and IL-4 release and enhances release induced by IgE cross-linking. Concomitant with mediator release, high levels of intracellular reactive oxygen species (ROS) were generated, and both ROS and serotonin release were inhibited by anti-oxidants. These findings suggest that alternative mechanisms exist whereby pollen exposure enhances allergic inflammatory mediator release through mechanisms that involve ROS. These mechanisms have the potential for enhancing the allergenic potency of pollens. PMID:21944563

Endo, Shuichiro; Hochman, Daniel J.; Midoro-Horiuti, Terumi; Goldblum, Randall M.; Brooks, Edward G.

2011-01-01

236

Physical vapour deposition reactive magnetron sputtering for the production and application of dichroics in photovoltaic system with solar spectral splitting  

NASA Astrophysics Data System (ADS)

This paper aims at designing, producing and characterizing a series of dichroic filters that are made up of a stack of layers with variable nanometer thickness. Such filters are created by PVD reactive magnetron sputtering, obtaining SiO2 and TiO2 through an active oxidation during the deposition. The single layers have then been analyzed using different techniques including RBS (Rutherford Backscattering Spectrometry) to determine the stoichiometry, AFM (Atomic Force Microscope) to assess the deposition rate, and UV-vis-NIR spectrophotometric analysis to evaluate the optical response. The application of the dichroic in concentration photovoltaic systems, separates the solar radiation in two optical spectral bands [7], that allows to couple them with a different solar cells which have dedicated external quantum efficiency. The optical separation using dichroic filters allows to combine different photovoltaic cells with an appropriate energy gap, thus optimizing the photovoltaic conversion.

Raniero, W.; Campostrini, M.; Maggioni, G.; Della Mea, G.; Quaranta, A.

2014-07-01

237

Detection of the production of reactive oxygen species by neutrophils in whole blood: modulation by adamantanes and triggering by Fe(3+)-ions.  

PubMed

Using indicators for the production of reactive oxygen species (ROS) such as the a) OH-radical type (alpha-keto-gamma-methiolbutyric acid, KMB) or b) hypochlorous acid (1-amino-cyclopropyl-1-carboxylic acid, ACC) neutrophil activities can be both quantified and differentiated in whole blood via ethene production. Ethene is trapped in the head space of blood samples incubated in the presence of zymosan and the respective indicators, KMB or ACC. This procedure allows the detection of effects of aminoadamantanes (AAD) such as amantadine or memantine, compounds frequently used for the treatment of Morbus Parkinson and Morbus Alzheimer. In this report we describe the detection of OH.-type oxidants produced by isolated activated neutrophils and whole blood. Immunomodulatory activities of AAD are deduced from the following observations: AAD-stimulated ethene formation from (KMB) as an indicator for production of OH.-type reactive oxygen species by zymosan-stimulated neutrophils ("respiratory burst") is detectable with isolated neutrophils. In whole blood, however, this reaction is only measurable in the presence of Fe-EDTA-complex. Stimulating effects of AAD are observed within a concentration range between 10(-8) and 10(-4) M with a maximum at 1 microM. Ethene release from (ACC) as indicator for the myeloperoxidase reaction after degranulation is not stimulated by AAD but inhibited at concentrations higher than 100 microM. The presented results suggest that submicromolar concentrations of AAD only stimulate the respiratory burst and apparently not degranulation of zymosan-prestimulated polymorphonuclear neutrophils (PMN). PMID:10488564

Schempp, H; Albrecht-Goepfert, E; Elstner, E F

1999-01-01

238

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

PubMed

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

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

2014-10-01

239

Understanding composite explosive energetics: 4. Reactive flow modeling of aluminum reaction kinetics in PETN and TNT using normalized product equation of state  

SciTech Connect

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.

Tao, W.C.; Tarver, C.M.; Kury, J.W.; Lee, C.G.; Ornellas, D.L.

1993-07-01

240

Long-chain bases and their phosphorylated derivatives differentially regulate cryptogein-induced production of reactive oxygen species in tobacco (Nicotiana tabacum) BY-2 cells.  

PubMed

The proteinaceous elicitor cryptogein triggers defence reactions in Nicotiana tabacum (tobacco) through a signalling cascade, including the early production of reactive oxygen species (ROS) by the plasma membrane (PM)-located tobacco respiratory burst oxidase homologue D (NtRbohD). Sphingolipid long-chain bases (LCBs) are emerging as potent positive regulators of plant defence-related mechanisms. This led us to question whether both LCBs and their phosphorylated derivatives (LCB-Ps) are involved in the early signalling process triggered by cryptogein in tobacco BY-2 cells. Here, we showed that cryptogein-induced ROS production was inhibited by LCB kinase (LCBK) inhibitors. Additionally, Arabidopsis thaliana sphingosine kinase 1 and exogenously supplied LCB-Ps increased cryptogein-induced ROS production, whereas exogenously supplied LCBs had a strong opposite effect, which was not driven by a reduction in cellular viability. Immunogold-electron microscopy assay also revealed that LCB-Ps are present in the PM, which fits well with the presence of a high LCBK activity associated with this fraction. Our data demonstrate that LCBs and LCB-Ps differentially regulate cryptogein-induced ROS production in tobacco BY-2 cells, and support a model in which a cooperative synergism between LCBK/LCB-Ps and NtRbohD/ROS in the cryptogein signalling pathway is likely at the PM in tobacco BY-2 cells. PMID:25303640

Coursol, Sylvie; Fromentin, Jérôme; Noirot, Elodie; Brière, Christian; Robert, Franck; Morel, Johanne; Liang, Yun-Kuan; Lherminier, Jeannine; Simon-Plas, Françoise

2015-02-01

241

Pycnogenol® inhibits lipid accumulation in 3T3-L1 adipocytes with the modulation of reactive oxygen species (ROS) production associated with antioxidant enzyme responses.  

PubMed

Pycnogenol® is a group of flavonoids with antioxidant effects. Adipogenesis is the process of adipocyte differentiation. It causes the increase of lipids as well as ROS (reactive oxygen species). Lipid accumulation and ROS production were determined in 3?T3-L1 adipocyte, and the effect of Pycnogenol® was evaluated. Lipid accumulation was elevated in adipocyte treated with hydrogen peroxide, one of the ROS. Pycnogenol® showed an inhibitory effect on the lipid accumulation and ROS production during the adipogenesis. We also investigated the molecular events associated with ROS production and lipid accumulation. Our results showed that Pycnogenol® inhibited the mRNA expression of pro-oxidant enzymes, such as NOX4 (NADPH (nicotinamide adenine dinucleotide phosphate hydrogen) oxidase 4), and the NADPH-producing G6PDH (glucose-6-phosphate dehydrogenase) enzyme. In addition, Pycnogenol® suppressed the mRNA abundance of adipogenic transcription factors, PPAR-? (peroxisome proliferator-activated receptor ?) and C/EBP-? (CCAAT/enhancer binding protein ?), and their target gene, aP2 (adipocyte protein 2) responsible for fatty acid transportation. On the other hand, Pycnogenol® increased the abundance of antioxidant proteins such as Cu/Zn-SOD (copper-zinc superoxide dismutase), Mn-SOD (manganese superoxide dismutase), GPx (glutathione peroxidase) and GR (glutathione reductase). Our results suggest that Pycnogenol® inhibits lipid accumulation and ROS production by regulating adipogenic gene expression and pro-/antioxidant enzyme responses in adipocytes. PMID:21796705

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

2012-03-01

242

Insights on the antitumor effects of kahweol on human breast cancer: decreased survival and increased production of reactive oxygen species and cytotoxicity.  

PubMed

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. PMID:24732357

Cárdenas, Casimiro; Quesada, Ana R; Medina, Miguel Ángel

2014-05-01

243

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

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 0.003 nM, with maximal induction occurring at 0.3 nM 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. ?? 2005 Elsevier B.V. All rights reserved.

Arzuaga, X.; Wassenberg, D.; Giulio, R.D.; Elskus, A.

2006-01-01

244

Phenylethynyl terminated reactive oligomer  

NASA Technical Reports Server (NTRS)

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.

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

1995-01-01

245

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

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

246

Comparative study between atmospheric microwave and low-frequency plasmas: Production efficiency of reactive species and their effectiveness  

NASA Astrophysics Data System (ADS)

The characteristics of low-frequency (LF) and microwave-powered plasmas were investigated. The optical emission of these two plasmas indicated that more chemicals were generated by microwave plasma than by LF plasma with the intensities being higher by factors of about 9, 3, 5, and 1.6 for OH (309 nm), O (777 nm), NO (247 nm), and Ca2+ (290 nm), respectively. Application experiments were also conducted. A steel plate became hydrophilic after 45 s of microwave plasma treatment. This is more than ten times faster than in the case of LF plasma treatment, an action related to the generation of reactive species (e.g., OH, O, and NO) as measured by optical emission spectroscopy (OES). Ca2+ generation was verified by blood coagulation experiment. Microwave-plasma-induced coagulation was twice faster than LF-plasma-induced coagulation. Simulation results that explain the chemical generation in microwave plasma were also included. High-energy electrons were considered a major factor for microwave plasma characteristics.

Won, Im Hee; Kim, Myoung Soo; Kim, Ho Young; Shin, Hyun Kook; Kwon, Hyoung Cheol; Sim, Jae Yoon; Lee, Jae Koo

2014-01-01

247

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

248

Multi-jet production in lepton-proton scattering at next-to-leading order accuracy  

E-print Network

I summarize the theoretical and experimental status of multijet production in DIS. I present the state of the art theoretical predictions and compare those to the corresponding experimental results obtained by analysing the data collected by the H1 and ZEUS collaborations at HERA. I also show new predictions for three-jet event-shape distributions at the NLO accuracy.

Z. Trocsanyi

2005-12-01

249

Observation of two-jet production in deep inelastic scattering at HERA  

Microsoft Academic Search

A sample of events with two distinct jets, in addition to the proton remnant, has been identified in deep inelastic, neutral current ep interactions recorded at HERA by the ZEUS experiment. For these events, the mass of the hadronic system ranges from 40 to 260 GeV. The salient features of the observed jet production agree with the predictions of higher

M. Derrick; D. Krakauer; S. Magill; B. Musgrave; J. Repond; S. Repond; R. Stanek; R. L. Talaga; J. Thron; F. Arzarello; R. Ayad; G. Bari; M. Basile; L. Bellagamba; D. Boscherini; A. Bruni; G. Bruni; P. Bruni; G. Cara Romeo; G. Castellini; M. Chiarini; L. Cifarelli; F. Cindolo; F. Ciralli; A. Contin; S. D'Auria; C. del Papa; F. Frasconi; P. Giusti; G. Iacobucci; G. Laurenti; G. Levi; Q. Lin; B. Lisowski; G. Maccarrone; A. Margotti; T. Massam; R. Nania; C. Nemoz; F. Palmonari; G. Sartorelli; R. Timellini; Y. Zamora Garcia; A. Zichichi; A. Bargende; J. Crittenden; H. Dabbous; K. Desch; B. Diekmann; T. Doeker; M. Geerts; G. Geitz; B. Gutjahr; H. Hartmann; D. Haun; K. Heinloth; E. Hilger; H.-P. Jakob; S. Kramarczyk; M. Kückes; A. Mass; S. Mengel; J. Mollen; D. Monaldi; H. Müsch; E. Paul; R. Schattevoy; J.-L. Schneider; R. Wedemeyer; A. Cassidy; D. G. Cussans; N. Dyce; H. F. Fawcett; B. Foster; R. Gilmore; G. P. Heath; M. Lancaster; T. J. Llewellyn; J. Malos; C. J. S. Morgado; R. J. Tapper; S. S. Wilson; R. R. Rau; M. Arneodo; T. Barillari; M. Schioppa; G. Susinno; A. Bernstein; A. Caldwell; I. Gialas; J. A. Parsons; S. Ritz; F. Sciulli; P. B. Straub; L. Wai; S. Yang; J. Chwastowski; A. Dwurazny; A. Eskreys; Z. Jakubowski; B. Niziom; K. Piotrzkowski; M. Zachara; L. Zawiejski; B. Bednarek; P. Borzemski; K. Eskreys; K. Jelen; D. Kisielewska; T. Kowalski; E. Rulikowska-Zarebska; L. Suszycki; J. Zajc; T. Kedzierski; A. Kotanski; M. Przybycien; L. A. T. Bauerdick; U. Behrens; J. K. Bienlein; C. Coldewey; A. Dannemann; G. Drews; P. Erhard; M. Flasinski; I. Fleck; R. Gläser; P. Göttlicher; T. Haas; L. Hagge; W. Hain; D. Hasell; H. Hultschig; G. Jahnen; P. Joos; M. Kasemann; R. Klanner; W. Koch; U. Kötz; H. Kowalski; J. Krüger; J. Labs; A. Ladage; B. Löhr; M. Löwe; D. Lüke; J. Mainusch; O. Manczak; M. Momayezi; J. S. T. Ng; S. Nickel; D. Notz; I. H. Park; K.-U. Pösnecker; M. Rohde; J. Roldán; E. Ros; U. Schneekloth; J. Schroeder; W. Schulz; F. Selonke; E. Stiliaris; E. Tscheslog; T. Tsurugai; F. Turkot; W. Vogel; G. Wolf; C. Youngman; H. J. Grabosch; A. Leich; A. Meyer; C. Rethfeldt; S. Schlenstedt; G. Barbagli; A. Francescato; M. Nuti; P. Pelfer; G. Anzivino; R. Casaccia; S. de Pasquale; S. Qian; L. Votano; A. Bamberger; A. Freidhof; T. Poser; S. Söldner-Rembold; G. Theisen; T. Trefzger; N. H. Brook; P. J. Bussey; A. T. Doyle; J. R. Forbes; V. A. Jamieson; C. Raine; D. H. Saxon; H. Brückmann; G. Gloth; U. Holm; H. Kammerlocher; B. Krebs; T. Neumann; K. Wick; A. Fürtjes; W. Kröger; E. Lohrmann; J. Milewski; M. Nakahata; N. Pavel; G. Poelz; A. Seidman; W. Schott; J. Terron; B. H. Wiik; F. Zetsche; T. C. Bacon; I. Butterworth; C. Markou; D. McQuillan; D. B. Miller; M. M. Mobayyen; A. Prinias; A. Vorvolakos; T. Bienz; H. Kreutzmann; U. Mallik; E. McCliment; M. Roco; M. Z. Wang; P. Cloth; D. Filges; L. Chen; R. Imlay; S. Kartik; H.-J. Kim; R. R. McNeil; W. Metcalf; F. Barreiro; G. Cases; L. Hervás; L. Labarga; J. del Peso; J. F. de Trocóniz; F. Ikraiam; J. K. Mayer; G. R. Smith; F. Corriveau; D. J. Gilkinson; D. S. Hanna; J. Hartmann; L. W. Hung; J. N. Lim; R. Meijer Drees; J. W. Mitchell; P. M. Patel; L. E. Sinclair; D. G. Stairs; R. Ullmann; G. L. Bashindzhagyan; P. F. Ermolov; L. K. Gladilin; Y. A. Golubkov; V. A. Kuzmin; E. N. Kuznetsov; A. A. Savin; A. G. Voronin; N. P. Zotov; S. Bentvelsen; M. Botje; A. Dake; J. Engelen; P. de Jong; M. de Kamps; P. Kooijman; A. Kruse; H. van der Lugt; V. O'dell; A. Tenner; H. Tiecke; H. Uijterwaal; M. Vreeswijk; L. Wiggers; E. de Wolf; R. van Woudenberg; R. Yoshida; B. Bylsma; L. S. Durkin; K. Honscheid; C. Li; T. Y. Ling; K. W. McLean; W. N. Murray; S. K. Park; T. A. Romanowski; R. Seidlein; G. A. Blair; A. Byrne; R. J. Cashmore; A. M. Cooper-Sarkar; R. C. E. Devenish; D. M. Gingrich; P. M. Hallam-Baker; N. Harnew; T. Khatri; K. R. Long; P. Luffman; I. McArthur; P. Morawitz; J. Nash; S. J. P. Smith; N. C. Roocroft; F. F. Wilson; G. Abbiendi; R. Brugnera; R. Carlin; F. dal Corso; M. de Giorgi; U. Dosselli; F. Gasparini; S. Limentani; M. Morandin; M. Posocco; L. Stanco; R. Stroili; C. Voci; J. M. Butterworth; J. Bulmahn; G. Field; B. Y. Oh; J. Whitmore; U. Contino; G. D'Agostini; M. Guida; M. Iori; S. M. Mari; G. Marini; M. Mattioli; A. Nigro; J. C. Hart; N. A. McCubbin; K. Prytz; T. P. Shah; T. L. Short; E. Barberis; N. Cartiglia; C. Heusch; B. Hubbard; J. Leslie; W. Lockman; K. O'Shaughnessy; H. F. Sadrozinski; A. Seiden; E. Badura; J. Biltzinger; H. Chaves; M. Rost; R. J. Seifert; A. H. Walenta; W. Weihs; G. Zech; S. Dagan; A. Levy; D. Zer-Zion; T. Hasegawa; M. Hazumi; T. Ishii; S. Kasai; M. Kuze; Y. Nagasawa; M. Nakao; H. Okuno; K. Tokushuku; T. Watanabe; S. Yamada; M. Chiba; R. Hamatsu; T. Hirose; S. Kitamura; S. Nagayama; Y. Nakamitsu; R. Cirio; M. Costa; M. I. Ferrero; L. Lamberti; S. Maselli; C. Peroni; A. Solano; A. Staiano

1993-01-01

250

A MEASUREMENT OF DIJET PRODUCTION IN NEUTRAL CURRENT DEEP INELASTIC SCATTERING WITH ZEUS AT HERA  

E-print Network

production cross sections are measured in the range 10 detector in deep in Hamburg some of the greatest in my life. I don't dare try to mention all of them. However, that \\stinking Accelerator . . . . . . . . . . . . . . . . . . . . . . 15 2.2 The ZEUS Detector

251

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

252

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

PubMed Central

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

2013-01-01

253

Differential Effects of AT1 Receptor and Ca++ Channel Blockade on Atherosclerosis, Inflammatory Gene Expression, and Production of Reactive Oxygen Species  

PubMed Central

Angiotensin II receptor blockade has been shown to inhibit atherosclerosis in several different animal models. We sought to determine if this effect was the result of blood pressure reduction per se or a result of the anti-inflammatory effects of receptor blockade. ApoE-deficient mice were fed a high fat diet and treated with either an angiotensin II receptor antagonist, candesartan (0.5 mg/kg/day, SC) or a calcium channel blocker, amlodipine (7.5 mg/kg/day, mixed with food). Atherosclerotic lesion area, aortic inflammatory gene expression as well as aortic H2O2 and superoxide production were assayed. We found that candesartan but not amlodipine treatment dramatically attenuated the development of atherosclerosis despite a similar reduction in blood pressure. Similarly, candesartan treatment inhibited aortic expression of inflammatory genes and production of reactive oxygen species, effects not seen with amlodipine. These data demonstrate that angiotensin II receptor blockade inhibits atherosclerosis by reducing vascular oxidative stress and inflammatory gene production independent of blood pressure reduction. PMID:17224157

Doran, Derek E.; Weiss, Daiana; Zhang, Yong; Griendling, Kathy K; Robert Taylor, W.

2007-01-01

254

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

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

Leclerc, Eric; Hamon, Jeremy; Legendre, Audrey; Bois, Frederic Y

2014-10-01

255

Antiplatelet Effect of Catechol Is Related to Inhibition of Cyclooxygenase, Reactive Oxygen Species, ERK/p38 Signaling and Thromboxane A2 Production  

PubMed Central

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 µM) suppressed AA-induced platelet aggregation and inhibited TXB2 production at concentrations of 0.5–5 µM; however, it showed little cytotoxicity and did not alter U46619-induced platelet aggregation. Catechol (10–50 µM) suppressed COX-1 activity by 29–44% and COX-2 activity by 29–50%. It also inhibited IL-1?-induced PGE2 production, but not COX-2 expression of fibroblasts. Moreover, catechol (1–10 µM) 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 (2.5–5 µmole/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

Wang, Tong-Mei; Lin, Bor-Ru; Yeung, Sin-Yuet; Yeh, Chien-Yang; Cheng, Ru-Hsiu; Jeng, Jiiang-Huei

2014-01-01

256

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

E-print Network

; revised 3 April 2002; accepted 5 April 2002; published 28 May 2002. [1] Observations of ozone (O3) and O3 concentrations that exceed the health- based National Ambient Air Quality Standard (NAAQS) [Environ- mental] Ozone production in the lower troposphere occurs by reac- tion of NOx (NO + NO2) and VOCs (volatile

257

Three-jet production in diffractive deep inelastic scattering at HERA  

Microsoft Academic Search

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

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

2001-01-01

258

D-Galacturonic acid as a highly reactive compound in nonenzymatic browning. 1. Formation of browning active degradation products.  

PubMed

Thermal treatment of an aqueous solution of D-galacturonic acid at pH 3, 5, and 8 led to rapid browning of the solution and to the formation of carbocyclic compounds such as reductic acid (2,3-dihydroxy-2-cyclopenten-1-one), DHCP (4,5-dihydroxy-2-cyclopenten-1-one), and furan-2-carbaldehyde, as degradation products in weak acidic solution. Studies on their formation revealed 2-ketoglutaraldehyde as their common key intermediate. Norfuraneol (4-hydroxy-5-methyl-3-(2H)-furanone) is a typical alkaline degradation product and formed after isomerization. Further model studies revealed reductic acid as an important and more browning active compound than furan-2-carbaldehyde, which led to a red color of the model solution. This red-brown color is also characteristic of thermally treated uronic acid solutions. PMID:23495718

Bornik, Maria-Anna; Kroh, Lothar W

2013-04-10

259

Reactive collisions of sulfur dioxide with molten carbonates  

PubMed Central

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

Krebs, Thomas; Nathanson, Gilbert M.

2010-01-01

260

Lactoferrin inhibits the binding of lipopolysaccharides to L-selectin and subsequent production of reactive oxygen species by neutrophils  

Microsoft Academic Search

The activation of leukocytes by lipopolysaccharides (LPS), resulting in the oxidative burst, contributes to the pathogenesis of septic shock. The binding of LPS to L-selectin, which was reported as a serum-independent LPS receptor on neutrophils, induces the production of oxygen free radicals. Human lactoferrin (hLf), an anti-inflammatory glycoprotein released from neutrophil granules during infection, binds to LPS. In this study,

Sophie Baveye; Elisabeth Elass; Joël Mazurier; Dominique Legrand

2000-01-01

261

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

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

262

Laccase and its role in production of extracellular reactive oxygen species during wood decay by the brown rot basidiomycete Postia placenta.  

PubMed

Brown rot basidiomycetes initiate wood decay by producing extracellular reactive oxygen species that depolymerize the structural polysaccharides of lignocellulose. Secreted fungal hydroquinones are considered one contributor because they have been shown to reduce Fe(3+), thus generating perhydroxyl radicals and Fe(2+), which subsequently react further to produce biodegradative hydroxyl radicals. However, many brown rot fungi also secrete high levels of oxalate, which chelates Fe(3+) tightly, making it unreactive with hydroquinones. For hydroquinone-driven hydroxyl radical production to contribute in this environment, an alternative mechanism to oxidize hydroquinones is required. We show here that aspen wood undergoing decay by the oxalate producer Postia placenta contained both 2,5-dimethoxyhydroquinone and laccase activity. Mass spectrometric analysis of proteins extracted from the wood identified a putative laccase (Joint Genome Institute P. placenta protein identification number 111314), and heterologous expression of the corresponding gene confirmed this assignment. Ultrafiltration experiments with liquid pressed from the biodegrading wood showed that a high-molecular-weight component was required for it to oxidize 2,5-dimethoxyhydroquinone rapidly and that this component was replaceable by P. placenta laccase. The purified laccase oxidized 2,5-dimethoxyhydroquinone with a second-order rate constant near 10(4) M(-1) s(-1), and measurements of the H(2)O(2) produced indicated that approximately one perhydroxyl radical was generated per hydroquinone supplied. Using these values and a previously developed computer model, we estimate that the quantity of reactive oxygen species produced by P. placenta laccase in wood is large enough that it likely contributes to incipient decay. PMID:20154118

Wei, Dongsheng; Houtman, Carl J; Kapich, Alexander N; Hunt, Christopher G; Cullen, Daniel; Hammel, Kenneth E

2010-04-01

263

Anti-inflammatory effects of erythromycin and tetracycline on Propionibacterium acnes induced production of chemotactic factors and reactive oxygen species by human neutrophils.  

PubMed

Propionibacterium acnes (P. acnes), an anaerobic pathogen, plays an important role in the pathogenesis of acne and seems to initiate the inflammatory process by producing neutrophil chemotactic factors (NCF). Once neutrophils attracted by bacterial chemoattractants reach the inflamed site, they release inflammatory mediators such as lysosomal enzymes and reactive oxygen species (ROS). Previously, it has been shown that antibiotics may affect acne by means other than their anti-bacterial effects. Thus, we investigated the effect of subminimal inhibitory concentration (sub-MIC) of tetracycline and erythromycin on production of NCF and ROS. NCF was tested in vivo in a mouse model and ROS was estimated on human PMNL in vitro, by nitroblue tetrazolium dye reduction test (NBT) and cytochrome-C reduction test. Tetracycline (CS-T) and Erythromycin (CS-E) treated cultures showed a significant reduction of 35.8% and 58.3% in NCF production respectively, as compared to P. acnes stimulated cultures. Tetracycline and erythromycin at their sub-MIC also significantly inhibited release of ROS from human PMNL. Thus, tetracycline and erythromycin, besides having antibacterial activity, also have an anti-inflammatory action. These antibiotics reduce the capacity of P. acnes to produce NCF, as well decrease its ability to induce ROS from PMNL. PMID:12546757

Jain, A; Sangal, L; Basal, E; Kaushal, G P; Agarwal, S K

2002-10-01

264

Advanced glycation end products induce human corneal epithelial cells apoptosis through generation of reactive oxygen species and activation of JNK and p38 MAPK pathways.  

PubMed

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

Shi, Long; Yu, Xiaoming; Yang, Hongling; Wu, Xinyi

2013-01-01

265

Mitochondrial reactive oxygen species production mediates ursolic acid-induced mitochondrial uncoupling and glutathione redox cycling, with protection against oxidant injury in H9c2 cells.  

PubMed

Ursolic acid (UA), a natural pentacyclic triterpenoid carboxylic acid, is a ubiquitous compound widely distributed in many plants, fruits and medicinal herbs worldwide. A previous study in our laboratory has shown that UA can increase the mitochondrial ATP generation capacity (ATP-GC) and a glutathione-dependent antioxidant response, thereby protecting against oxidant injury in H9c2 cells in vitro and rat hearts ex vivo. However, the mechanism underlying the cellular protective effects induced by UA remains largely unknown. The present study has shown that pre-incubation with UA produces a transient increase in the mitochondrial membrane potential in H9c2 cells, which was accompanied by increases in mitochondrial reactive oxygen species (ROS) production. Studies using an antioxidant (dimethylthiourea) indicated that the suppression of mitochondrial ROS completely abrogated the UA-induced enhancement of mitochondrial uncoupling and glutathione reductase (GR)-mediated glutathione redox cycling, as well as protection against menadione cytotoxicity in H9c2 cells. Co-incubation with specific inhibitors of uncoupling proteins and GR almost completely prevented the cytoprotection afforded by UA against menadione-induced cytotoxicity in H9c2 cells. The results obtained so far suggest that UA-induced mitochondrial ROS production can elicit mitochondrial uncoupling and glutathione-dependent antioxidant responses, which offer cytoprotection against oxidant injury in H9c2 cells. PMID:25515785

Chen, Jihang; Wong, Hoi Shan; Ko, Kam Ming

2015-02-11

266

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

PubMed Central

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

Bonfim-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

267

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

SciTech Connect

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

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

2011-11-04

268

Picroside ? inhibits hypoxia/reoxygenation-induced cardiomyocyte apoptosis by ameliorating mitochondrial function through a mechanism involving a decrease in reactive oxygen species production.  

PubMed

Reactive oxygen species (ROS)?induced mitochondrial dysfunction plays an important role in cardiomyocyte apoptosis during myocardial ischemia/reperfusion (I/R) injury. Picroside ?, isolated from Picrorhiza scrophulariiflora Pennell (Scrophulariaceae), has been reported to protect cardiomyocytes from hypoxia/reoxygenation (H/R)?induced apoptosis, but the exact mechanism is not fully clear. The aim of the present study was to explore the protective effects of picroside ? on H/R?induced cardiomyocyte apoptosis and the underlying mechanism. In the H9c2 rat cardiomyocyte cell line, picroside ? (100 µg/ml) was added for 48 h prior to H/R. The results showed that picroside ? markedly inhibited H/R?induced cardiomyocyte apoptosis. In addition, picroside ? was also able to decrease the opening degree of mitochondrial permeability transition pore (mPTP), increase the mitochondrial membrane potential, inhibit cytochrome c release from mitochondria to cytosol and downregulate caspase?3 expression and activity concomitantly with the decreased ROS production. These results suggested that picroside ? inhibited H/R?induced cardiomyocyte apoptosis by ameliorating mitochondrial function through a mechanism involving a decrease in ROS production. PMID:25421707

Li, Jian-Zhe; Yu, Shu-Yi; Mo, Dan; Tang, Xiu-Neng; Shao, Qing-Rui

2015-02-01

269

Effects of Selected Dietary Secondary Metabolites on Reactive Oxygen Species Production Caused by Iron(II) Autoxidation.  

PubMed

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

Chobot, Vladimir; Hadacek, Franz; Kubicova, Lenka

2014-01-01

270

Effect of gold nanoparticles on production of reactive oxygen species by human peripheral blood leukocytes stimulated with opsonized zymosan.  

PubMed

We studied the effect of gold nanoparticles on ROS production by leukocytes. ROS production was detected by luminol-dependent chemiluminescence (LDCL) of human peripheral blood leukocytes stimulated with opsonized zymosan. Nanoparticle size was 5, 10 and 30 nm. Simultaneous addition of nanoparticles and opsonized zymosan showed that 5-nm nanoparticles inhibited LDCL intensity in comparison with the control, when LDCL recording was conducted in the presence of opsonized zymosan. Increasing nanoparticle size from 5 up to 30 nm enhanced LDCL intensity. Preincubation of gold nanoparticles with autologous blood plasma increased LDCL intensity. In the control (without gold nanoparticles), blood plasma produced no activating effect on LDCL. We found that the effect of gold nanoparticles on leukocyte LDCL depended on nanoparticle size: 10- and 30-nm nanoparticles inhibited LDCL intensity in comparison with the control (incubation in the absence of nanoparticles) irrespective of the duration of incubation, while 5-nm gold nanoparticles had no effect on LDCL intensity. Incubation of gold nanoparticles with autologous plasma increased LDCL intensity if nanoparticle size was 30 and 10 nm. PMID:24319701

Piryazev, A P; Azizova, O A; Aseichev, A V; Dudnik, L B; Sergienko, V I

2013-11-01

271

Stable production of TiOx nanoparticles with narrow size distribution by reactive pulsed dc magnetron sputtering  

NASA Astrophysics Data System (ADS)

The pulsed dc magnetron technique was used for generating TiOx nanoparticles by sputtering from a titanium target in a gas aggregation source. It was observed that the deposition rate (DR) of nanoparticles shows a peak followed by a broad tail, even for constant operation conditions. As a key finding of the present investigation, we show that nanoparticle deposition can be stabilized at nonzero DR for the pulsed power regime. Monitoring the oxygen concentration by mass spectrometry provides insight into nanoparticle generation in different processes. Characterization of the nanoparticle film morphology based on transmission electron microscopy reveals a very narrow size distribution. Furthermore, the oxygen admixture has a significant influence on the size distribution and also on the mean size of the formed nanoparticles. In situ analysis of the chemical composition of the deposited films directly after preparation by x-ray photoelectron spectroscopy shows a major contribution by sub-oxide titanium compounds to nanoparticle production.

Ahadi, Amir Mohammad; Polonskyi, Oleksandr; Schürmann, Ulrich; Strunskus, Thomas; Faupel, Franz

2015-01-01

272

Biofilm-Grown Burkholderia cepacia Complex Cells Survive Antibiotic Treatment by Avoiding Production of Reactive Oxygen Species  

PubMed Central

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 ?katA and ?katB 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

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

273

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

PubMed

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 unravelled. 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 sdh4? strain expressing shh4. Although shh4? cells showed no respiratory deficient phenotypes, deletion of SHH4 in sdh4? cells further abolished mitochondrial function. Remarkably, sdh4? shh4? strains exhibited increased ROS production, nuclear DNA instability, and mtDNA mutability and decreased chronological life span (CLS). 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. PMID:25328978

Chang, Ya-Lan; Hsieh, Meng-Hsun; Chang, Wei-Wen; Wang, Hurng-Yi; Lin, Mei-Chun; Wang, Cheng-Ping; Lou, Pei-Jen; Teng, Shu-Chun

2014-10-20

274

ESEEM of industrial silica-bearing powders: reactivity of defects during wet processing in the ceramics production  

NASA Astrophysics Data System (ADS)

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.

Romanelli, Maurizio; Di Benedetto, Francesco; Fornaciai, Gabriele; Innocenti, Massimo; Montegrossi, Giordano; Pardi, Luca A.; Zoleo, Alfonso; Capacci, Fabio

2014-12-01

275

Intravenous Immunoglobulin Prevents Murine Antibody-Mediated Acute Lung Injury at the Level of Neutrophil Reactive Oxygen Species (ROS) Production  

PubMed Central

Transfusion-related acute lung injury (TRALI) is a leading cause of transfusion-associated mortality that can occur with any type of transfusion and is thought to be primarily due to donor antibodies activating pulmonary neutrophils in recipients. Recently, a large prospective case controlled clinical study of cardiac surgery patients demonstrated that despite implementation of male donors, a high incidence of TRALI still occurred and suggested a need for additional interventions in susceptible patient populations. To examine if intravenous immunoglobulin (IVIg) may be effective, a murine model of antibody-mediated acute lung injury that approximates human TRALI was examined. When BALB/c mice were injected with the anti-major histocompatibility complex class I antibody 34-1-2s, mild shock (reduced rectal temperature) and respiratory distress (dyspnea) were observed and pre-treatment of the mice with 2 g/kg IVIg completely prevented these symptoms. To determine IVIg's usefulness to affect severe lung damage, SCID mice, previously shown to be hypersensitive to 34-1-2s were used. SCID mice treated with 34-1-2s underwent severe shock, lung damage (increased wet/dry ratios) and 40% mortality within 2 hours. Treatment with 2 g/kg IVIg 18 hours before 34-1-2s administration completely protected the mice from all adverse events. Treatment with IVIg after symptoms began also reduced lung damage and mortality. While the prophylactic IVIg administration did not affect 34-1-2s-induced pulmonary neutrophil accumulation, bone marrow-derived neutrophils from the IVIg-treated mice displayed no spontaneous ROS production nor could they be stimulated in vitro with fMLP or 34-1-2s. These results suggest that IVIg prevents murine antibody-mediated acute lung injury at the level of neutrophil ROS production and thus, alleviating tissue damage. PMID:22363629

Semple, John W.; Kim, Michael; Hou, Jing; McVey, Mark; Lee, Young Jin; Tabuchi, Arata; Kuebler, Wolfgang M.; Chai, Zhong-Wei; Lazarus, Alan H.

2012-01-01

276

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

SciTech Connect

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

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

2007-01-15

277

DEXH Box RNA Helicase–Mediated Mitochondrial Reactive Oxygen Species Production in Arabidopsis Mediates Crosstalk between Abscisic Acid and Auxin Signaling[C][W][OA  

PubMed Central

It is well known that abscisic acid (ABA) promotes reactive oxygen species (ROS) production through plasma membrane–associated 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

He, Junna; Duan, Ying; Hua, Deping; Fan, Guangjiang; Wang, Li; Liu, Yue; Chen, Zhizhong; Han, Lihua; Qu, Li-Jia; Gong, Zhizhong

2012-01-01

278

Preventive effect of Daiokanzoto (TJ-84) on 5-fluorouracil-induced human gingival cell death through the inhibition of reactive oxygen species production.  

PubMed

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

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

2014-01-01

279

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

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

Baruah, Kartik; Norouzitallab, Parisa; Linayati, Linayati; Sorgeloos, Patrick; Bossier, Peter

2014-10-01

280

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

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

Kitagawa, Takehiro; Yamamoto, Junkoh; Tanaka, Tohru; Nakano, Yoshiteru; Akiba, Daisuke; Ueta, Kunihiro; Nishizawa, Shigeru

2015-02-01

281

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

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

282

Toll-Like Receptor 4 Upregulation by Angiotensin II Contributes to Hypertension and Vascular Dysfunction through Reactive Oxygen Species Production  

PubMed Central

Hypertension is considered as a low-grade inflammatory disease, with adaptive immunity being an important mediator of this pathology. TLR4 may have a role in the development of several cardiovascular diseases; however, little is known about its participation in hypertension. We aimed to investigate whether TLR4 activation due to increased activity of the renin-angiotensin system (RAS) contributes to hypertension and its associated endothelial dysfunction. For this, we used aortic segments from Wistar rats treated with a non-specific IgG (1 µg/day) and SHRs treated with losartan (15 mg/kg·day), the non-specific IgG or the neutralizing antibody anti-TLR4 (1 µg/day), as well as cultured vascular smooth muscle cells (VSMC) from Wistar and SHRs. TLR4 mRNA levels were greater in the VSMC and aortas from SHRs compared with Wistar rats; losartan treatment reduced those levels in the SHRs. Treatment of the SHRs with the anti-TLR4 antibody: 1) reduced the increased blood pressure, heart rate and phenylephrine-induced contraction while it improved the impaired acetylcholine-induced relaxation; 2) increased the potentiation of phenylephrine contraction after endothelium removal; and 3) abolished the inhibitory effects of tiron, apocynin and catalase on the phenylephrine-induced response as well as its enhancing effect of acetylcholine-induced relaxation. In SHR VSMCs, angiotensin II increased TLR4 mRNA levels, and losartan reduced that increase. CLI-095, a TLR4 inhibitor, mitigated the increases in NAD(P)H oxidase activity, superoxide anion production, migration and proliferation that were induced by angiotensin II. In conclusion, TLR4 pathway activation due to increased RAS activity is involved in hypertension, and by inducing oxidative stress, this pathway contributes to the endothelial dysfunction associated with this pathology. These results suggest that TLR4 and innate immunity may play a role in hypertension and its associated end-organ damage. PMID:25093580

De Batista, Priscila R.; Palacios, Roberto; Martín, Angela; Hernanz, Raquel; Médici, Cindy T.; Silva, Marito A. S. C.; Rossi, Emilly M.; Aguado, Andrea; Vassallo, Dalton V.; Salaices, Mercedes; Alonso, María J.

2014-01-01

283

A Tariff for Reactive Power  

SciTech Connect

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.

Kueck, John D [ORNL; Kirby, Brendan J [ORNL; Li, Fangxing [ORNL; Tufon, Christopher [Pacific Gas and Electric Company; Isemonger, Alan [California Independent System Operator

2008-07-01

284

Jaridonin, a novel ent-kaurene diterpenoid from Isodon rubescens, inducing apoptosis via production of reactive oxygen species in esophageal cancer cells.  

PubMed

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

Ma, Yong-Cheng; Ke, Yu; Zi, Xiaolin; Zhao, Wen; Shi, Xiao-Jing; Liu, Hong-Min

2013-07-01

285

[The effect of ATP-dependent K(+)-channel opener on transmembrane potassium exchange and reactive oxygen species production upon the opening of mitochondrial pore].  

PubMed

The effect of mitochondrial ATP-dependent K(+)-channel (K(+)ATP-channel) opener diazoxide (DZ) on transmembrane potassium exchange and reactive oxygen species (ROS) formation under the opening of mitochondrial permeability transition pore (MPTP) was studied in rat liver mitochondria. The activation of K(+)-cycling (K(+)-uptake and K(+)/H(+)-exchange) by DZ was established with peak effect at < or = 500 nM. It was shown that MPTP opening as well resulted in the activation of K(+)-cycling together with simultaneous activation of Ca(2+)-cycle in mitochondria. In the absence of depolarization Ca(2+)-cycle is supported by MPTP and Ca(2+)-uniporter. The stimulation of K(+)/H(+)-exchange by MPTP opening led to the activation of K(+)-cycle, but further activation of K(+)/H(+)-exchange resulted in MPTP inhibition. Under the same conditions the decrease in mitochondrial ROS production was observed. It was proposed that the decrease in ROS formation together with K(+)/H(+)-exchange activation could be the constituents of the complex effect of MPTP inhibition induced by K(+)ATP-channel opener. PMID:24868909

Akopova, O V; Kolchinskaia, L I; Nosar', V I; Bury?, V A; Man'kovskaia, I N; Sagach, V F

2014-01-01

286

Uncoupling protein-2 attenuates palmitoleate protection against the cytotoxic production of mitochondrial reactive oxygen species in INS-1E insulinoma cells  

PubMed Central

High glucose and fatty acid levels impair pancreatic beta cell function. We have recently shown that palmitate-induced loss of INS-1E insulinoma cells is related to increased reactive oxygen species (ROS) production as both toxic effects are prevented by palmitoleate. Here we show that palmitate-induced ROS are mostly mitochondrial: oxidation of MitoSOX, a mitochondria-targeted superoxide probe, is increased by palmitate, whilst oxidation of the equivalent non-targeted probe is unaffected. Moreover, mitochondrial respiratory inhibition with antimycin A stimulates palmitate-induced MitoSOX oxidation. We also show that palmitate does not change the level of mitochondrial uncoupling protein-2 (UCP2) and that UCP2 knockdown does not affect palmitate-induced MitoSOX oxidation. Palmitoleate does not influence MitoSOX oxidation in INS-1E cells ±UCP2 and largely prevents the palmitate-induced effects. Importantly, UCP2 knockdown amplifies the preventive effect of palmitoleate on palmitate-induced ROS. Consistently, viability effects of palmitate and palmitoleate are similar between cells ±UCP2, but UCP2 knockdown significantly augments the palmitoleate protection against palmitate-induced cell loss at high glucose. We conclude that UCP2 neither mediates palmitate-induced mitochondrial ROS generation and the associated cell loss, nor protects against these deleterious effects. Instead, UCP2 dampens palmitoleate protection against palmitate toxicity. PMID:25482405

Barlow, Jonathan; Hirschberg Jensen, Verena; Affourtit, Charles

2014-01-01

287

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

PubMed

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

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

2014-01-01

288

Uncoupling protein-2 attenuates palmitoleate protection against the cytotoxic production of mitochondrial reactive oxygen species in INS-1E insulinoma cells.  

PubMed

High glucose and fatty acid levels impair pancreatic beta cell function. We have recently shown that palmitate-induced loss of INS-1E insulinoma cells is related to increased reactive oxygen species (ROS) production as both toxic effects are prevented by palmitoleate. Here we show that palmitate-induced ROS are mostly mitochondrial: oxidation of MitoSOX, a mitochondria-targeted superoxide probe, is increased by palmitate, whilst oxidation of the equivalent non-targeted probe is unaffected. Moreover, mitochondrial respiratory inhibition with antimycin A stimulates palmitate-induced MitoSOX oxidation. We also show that palmitate does not change the level of mitochondrial uncoupling protein-2 (UCP2) and that UCP2 knockdown does not affect palmitate-induced MitoSOX oxidation. Palmitoleate does not influence MitoSOX oxidation in INS-1E cells ±UCP2 and largely prevents the palmitate-induced effects. Importantly, UCP2 knockdown amplifies the preventive effect of palmitoleate on palmitate-induced ROS. Consistently, viability effects of palmitate and palmitoleate are similar between cells ±UCP2, but UCP2 knockdown significantly augments the palmitoleate protection against palmitate-induced cell loss at high glucose. We conclude that UCP2 neither mediates palmitate-induced mitochondrial ROS generation and the associated cell loss, nor protects against these deleterious effects. Instead, UCP2 dampens palmitoleate protection against palmitate toxicity. PMID:25482405

Barlow, Jonathan; Hirschberg Jensen, Verena; Affourtit, Charles

2014-11-28

289

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

PubMed Central

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

Kühl, Michael

2013-01-01

290

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

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

291

TEGDMA-induced toxicity in human fibroblasts is associated with early and drastic glutathione depletion with subsequent production of oxygen reactive species.  

PubMed

Triethylene glycol dimethacrylate (TEGDMA) is a dentin-bonding agent and a major component of various dental restorative biomaterials. TEGDMA monomers are released from dental resins and induce dental pulp inflammation and necrosis. In this study, we have investigated the mechanism of TEGDMA-induced cytotoxicity of fibroblasts. Treatment of cultured human gingival and pulpal fibroblasts with 0.1-3 mM of TEGDMA for 24 h induced a concentration-dependent and variable cytotoxic effect. Fifty percent of toxicity (TC(50)) was obtained with 1.2 +/- 0.9 and 2.6 +/- 1.1 mM of TEGDMA for gingival and pulpal fibroblasts, respectively. Moreover, TEGDMA-induced cytotoxicity was associated with an early and drastic depletion of cellular glutathione (GSH), which started at 15-30 min and was almost complete at 4-6 h. Antioxidants, such as Trolox (0.01 mM), ascorbate (0.2 mM), and N-acetylcysteine (NAC) (5 mM) prevented the TEGDMA-induced cytotoxicity while GSH depletion was partially inhibited. Finally, a late production of reactive oxygen species (ROS) occurred in fibroblasts treated with TEGDMA for 3-4 h, as determined by 2',7'-dichlorofluorescein fluorescence, and was completely inhibited by Trolox (5 microM). The data show that TEGDMA induced a drastic GSH depletion followed by production of ROS, which may contribute to the toxicity of gingival and pulpal fibroblasts. Antioxidants, such as NAC, ascorbate, and particularly Trolox, appear useful in preventing cell damage mediated by resin-containing dental restorative materials. PMID:12918029

Stanislawski, Lena; Lefeuvre, Mathieu; Bourd, Katia; Soheili-Majd, Esmat; Goldberg, Michel; Périanin, Axel

2003-09-01

292

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

PubMed Central

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

2014-01-01

293

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

PubMed Central

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

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

2013-01-01

294

Modulation of reactive oxygen species production during osmotic stress in Arabidopsis thaliana cultured cells: involvement of the plasma membrane Ca2+-ATPase and H+-ATPase.  

PubMed

In Arabidopsis thaliana cells, hypoosmotic treatment initially stimulates Ca2+ influx and inhibits its efflux and, concurrently, promotes a large H2O2 accumulation in the external medium, representative of reactive oxygen species (ROS) production. After the first 10-15 min, Ca2+ influx rate is, however, lowered, and a large rise in Ca2+ efflux, concomitant with a rapid decline in H2O2 level, takes place. The drop of the H2O2 peak, as well as the efflux of Ca2+, are prevented by treatment with submicromolar concentrations of eosin yellow (EY), selectively inhibiting the Ca2+-ATPase of the plasma membrane (PM). Comparable changes of Ca2+ fluxes are also induced by hyperosmotic treatment. However, in this case, the H2O2 level does not rise, but declines below control levels when Ca2+ efflux is activated. Also K+ and H+ net fluxes across the PM and cytoplasmic pH (pH(cyt)) are very differently influenced by the two opposite stresses: strongly decreased by hypoosmotic stress and increased under hyperosmotic treatment. The H2O2 accumulation kinetics, followed as a function of the pH(cyt) changes imposed by modulation of the PM H+-ATPase activity or weak acid treatment, show a close correlation between pH(cyt) and H2O2 formed, a larger amount being produced for changes towards acidic pH values. Overall, these results confirm a relevant role for the PM Ca2+-ATPase in switching off the signal triggering ROS production, and propose a role for the PM H+-ATPase in modulating the development of the oxidative wave through the pH(cyt) changes following the changes of its activity induced by stress conditions. PMID:15937326

Beffagna, Nicoletta; Buffoli, Barbara; Busi, Chiara

2005-08-01

295

The plant defense elicitor cryptogein stimulates clathrin-mediated endocytosis correlated with reactive oxygen species production in bright yellow-2 tobacco cells.  

PubMed

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

Leborgne-Castel, Nathalie; Lherminier, Jeannine; Der, Christophe; Fromentin, Jérôme; Houot, Valérie; Simon-Plas, Françoise

2008-03-01

296

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

PubMed

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

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

2000-03-01

297

p-Cresol Affects Reactive Oxygen Species Generation, Cell Cycle Arrest, Cytotoxicity and Inflammation/Atherosclerosis-Related Modulators Production in Endothelial Cells and Mononuclear Cells  

PubMed Central

Aims Cresols are present in antiseptics, coal tar, some resins, pesticides, and industrial solvents. Cresol intoxication leads to hepatic injury due to coagulopathy as well as disturbance of hepatic circulation in fatal cases. Patients with uremia suffer from cardiovascular complications, such as atherosclerosis, thrombosis, hemolysis, and bleeding, which may be partly due to p-cresol toxicity and its effects on vascular endothelial and mononuclear cells. Given the role of reactive oxygen species (ROS) and inflammation in vascular thrombosis, the objective of this study was to evaluate the effect of p-cresol on endothelial and mononuclear cells. Methods EA.hy926 (EAHY) endothelial cells and U937 cells were exposed to different concentrations of p-cresol. Cytotoxicity was evaluated by 3-(4,5-Dimethylthiazol-2-yl)-2,5 -diphenyltetrazolium bromide (MTT) assay and trypan blue dye exclusion technique, respectively. Cell cycle distribution was analyzed by propidium iodide flow cytometry. Endothelial cell migration was studied by wound closure assay. ROS level was measured by 2?,7?-dichlorofluorescein diacetate (DCF) fluorescence flow cytometry. Prostaglandin F2? (PGF2?), plasminogen activator inhibitor-1 (PAI-1), soluble urokinase plasminogen activator receptor (suPAR), and uPA production were determined by Enzyme-linked immunosorbant assay (ELISA). Results Exposure to 100–500 µM p-cresol decreased EAHY cell number by 30–61%. P-cresol also decreased the viability of U937 mononuclear cells. The inhibition of EAHY and U937 cell growth by p-cresol was related to induction of S-phase cell cycle arrest. Closure of endothelial wounds was inhibited by p-cresol (>100 µM). P-cresol (>50 µM) also stimulated ROS production in U937 cells and EAHY cells but to a lesser extent. Moreover, p-cresol markedly stimulated PAI-1 and suPAR, but not PGF2?, and uPA production in EAHY cells. Conclusions p-Cresol may contribute to atherosclerosis and thrombosis in patients with uremia and cresol intoxication possibly due to induction of ROS, endothelial/mononuclear cell damage and production of inflammation/atherosclerosis-related molecules. PMID:25517907

Chan, Chiu-Po; Yeung, Sin-Yuet; Hsien, Hsiang-Chi; Lin, Bor-Ru; Yeh, Chien-Yang; Tseng, Wan-Yu; Tseng, Shui-Kuan; Jeng, Jiiang-Huei

2014-01-01

298

Use of Multi-Angle Laser Light Scattering and Size-Exclusion Chromatography to Characterize the Molecular Weight and Types of Aggregates Present in Commercial Whey Protein Products  

Microsoft Academic Search

In this study, a range of commercial whey protein products were characterized by the use of size-exclusion chromatography coupled with a multi-angle laser light scattering (MALLS) detector. The MALLS system de- tected some very large-sized material that eluted close to void volume in all samples; this material was hardly detected by concentration detector. It was demon- strated by chitosan treatment

T. Wang; J. A. Lucey

2003-01-01

299

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

300

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

PubMed

Fully quantum state selected and resolved inelastic scattering of NO(X) by krypton has been investigated. Initial ?-doublet state selection is achieved using an inhomogeneous hexapole electric field. Differential cross sections and even-moment polarization dependent differential cross sections have been obtained at a collision energy of 514 cm(-1) for both spin-orbit and parity conserving and changing collisions. Experimental results are compared with those obtained from quantum scattering calculations and are shown to be in very good agreement. Hard shell quantum scattering calculations are also performed to determine the effects of the different parts of the potential on the scattering dynamics. Comparisons are also made with the NO(X) + Ar system. PMID:25362298

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

2014-10-28

301

Deep inelastic scattering of leptons*  

PubMed Central

The description of deep inelastic scattering as an extrapolation between resonance production and diffractive scattering is extended to give successful quantitative representations for the structure functions of unpolarized electron scattering on protons and neutrons, and of neutrino, antineutrino scattering on nucleons. The same ideas also supply a prediction for the polarization asymmetry in deep inelastic electron-proton scattering (paper no. 2, to be published). PMID:16592352

Schwinger, Julian

1976-01-01

302

Reactive Oxygen Species Production and Mitochondrial Dysfunction in White Blood Cells Are Not Valid Biomarkers of Ageing in the Very Old  

PubMed Central

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

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

303

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

SciTech Connect

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

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

1989-02-01

304

Suppressive subtractive hybridization approach revealed differential expression of hypersensitive response and reactive oxygen species production genes in tea (Camellia sinensis (L.) O. Kuntze) leaves during Pestalotiopsis thea infection.  

PubMed

Tea (Camellia sinensis (L.) O. Kuntze) is an economically important plant cultivated for its leaves. Infection of Pestalotiopsis theae in leaves causes gray blight disease and enormous loss to the tea industry. We used suppressive subtractive hybridization (SSH) technique to unravel the differential gene expression pattern during gray blight disease development in tea. Complementary DNA from P. theae-infected and uninfected leaves of disease tolerant cultivar UPASI-10 was used as tester and driver populations respectively. Subtraction efficiency was confirmed by comparing abundance of ?-actin gene. A total of 377 and 720 clones with insert size >250 bp from forward and reverse library respectively were sequenced and analyzed. Basic Local Alignment Search Tool analysis revealed 17 sequences in forward SSH library have high degree of similarity with disease and hypersensitive response related genes and 20 sequences with hypothetical proteins while in reverse SSH library, 23 sequences have high degree of similarity with disease and stress response-related genes and 15 sequences with hypothetical proteins. Functional analysis indicated unknown (61 and 59 %) or hypothetical functions (23 and 18 %) for most of the differentially regulated genes in forward and reverse SSH library, respectively, while others have important role in different cellular activities. Majority of the upregulated genes are related to hypersensitive response and reactive oxygen species production. Based on these expressed sequence tag data, putative role of differentially expressed genes were discussed in relation to disease. We also demonstrated the efficiency of SSH as a tool in enriching gray blight disease related up- and downregulated genes in tea. The present study revealed that many genes related to disease resistance were suppressed during P. theae infection and enhancing these genes by the application of inducers may impart better disease tolerance to the plants. PMID:23065401

Senthilkumar, Palanisamy; Thirugnanasambantham, Krishnaraj; Mandal, Abul Kalam Azad

2012-12-01

305

Resonance Raman spectral properties of FMN of bovine heart NADH:ubiquinone oxidoreductase suggesting a mechanism for the prevention of spontaneous production of reactive oxygen species.  

PubMed

A highly improved method for obtaining resonance Raman (RR) spectra provided spectra comparable to the best known flavoprotein spectra when the method was tested using bovine heart NADH:ubiquinone oxidoreductase (Complex I), a protein with a molecular mass of 1000 kDa, which causes the level of RR noise to be 1 order of magnitude higher than for most flavoproteins. The FMN RR band shift (1631/1633 cm(-1)) and the increase in the magnitude of the band at 1252 cm(-1) upon binding to Complex I suggest hydrogen bond formation involving one of the C=O groups [C(2)=O] of isoalloxazine to stabilize its quinoid form. This lowers the redox potential of FMN and the electron density of the O(2) binding site [a carbon atom, C(4a)] in the reduced form. Thus, spontaneous production of reactive oxygen species at the FMN site is prevented by minimizing the duration of the fully reduced state by accelerating the FMN oxidation and by weakening the O(2) affinity of C(4a). Other band shifts (1258/1252 cm(-1) and 1161/1158 cm(-1)) suggest a significantly weaker hydrogen bond to the NH group [N(3)-H] of isoalloxazine. This result, together with the reported X-ray structure in which N(3)-H is surrounded by negatively charged surface without hydrogen bond formation, suggests that N(3)-H is weakly but significantly polarized. The polarized N(3)-H, adjacent to the C(2)=O group, stabilizes the polarized state of C(2)=O to strengthen the hydrogen bond to C(2)=O. This could fine-tune the hydrogen bond strength. Other results show a high-dielectric constant environment and weak hydrogen bonds to the isoalloxazine, suggesting adaptability for various functional controls. PMID:23215454

Hikita, Masahide; Shinzawa-Itoh, Kyoko; Moriyama, Masakazu; Ogura, Takashi; Kihira, Kiyohito; Yoshikawa, Shinya

2013-01-01

306

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

307

Reactive arthritis.  

PubMed

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

Stavropoulos, P G; Soura, E; Kanelleas, A; Katsambas, A; Antoniou, C

2015-03-01

308

Phenylethynyl endcapping reagents and reactive diluents  

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

309

Blood Radicals: Reactive Nitrogen Species, Reactive Oxygen Species, Transition Metal Ions, and the Vascular System  

Microsoft Academic Search

Free radicals, such as superoxide, hydroxyl and nitric oxide, and other “reactive species”, such as hydrogen peroxide, hypochlorous acid and peroxynitrite, are formed in vivo. Some of these molecules, e.g. superoxide and nitric oxide, can be physiologically useful, but they can also cause damage under certain circumstances. Excess production of reactive oxygen or nitrogen species (ROS, RNS), their production in

Victor Darley-Usmar; Barry Halliwell

1996-01-01

310

Reactive collisions in confined geometries  

E-print Network

We consider low energy threshold reactive collisions of particles interacting via a van der Waals potential at long range in the presence of external confinement and give analytic formulas for the confinement modified scattering in such circumstances. The reaction process is described in terms of the short range reaction probability. Quantum defect theory is used to express elastic and inelastic or reaction collision rates analytically in terms of two dimensionless parameters representing phase and reactivity. We discuss the modifications to Wigner threshold laws for quasi-one-dimensional and quasi-two-dimensional geometries. Confinement-induced resonances are suppressed due to reactions and are completely absent in the universal limit where the short-range loss probability approaches unity.

Idziaszek, Zbigniew; Julienne, Paul S

2014-01-01

311

Reactive collisions in confined geometries  

E-print Network

We consider low energy threshold reactive collisions of particles interacting via a van der Waals potential at long range in the presence of external confinement and give analytic formulas for the confinement modified scattering in such circumstances. The reaction process is described in terms of the short range reaction probability. Quantum defect theory is used to express elastic and inelastic or reaction collision rates analytically in terms of two dimensionless parameters representing phase and reactivity. We discuss the modifications to Wigner threshold laws for quasi-one-dimensional and quasi-two-dimensional geometries. Confinement-induced resonances are suppressed due to reactions and are completely absent in the universal limit where the short-range loss probability approaches unity.

Zbigniew Idziaszek; Krzysztof Jachymski; Paul S. Julienne

2015-02-06

312

Reactive collisions in confined geometries  

E-print Network

We consider low energy threshold reactive collisions of particles interacting via a van der Waals potential at long range in the presence of external confinement and give analytic formulas for the confinement modified scattering in such circumstances. The reaction process is described in terms of the short range reaction probability. Quantum defect theory is used to express elastic and inelastic or reaction collision rates analytically in terms of two dimensionless parameters representing phase and reactivity. We discuss the modifications to Wigner threshold laws for quasi-one-dimensional and quasi-two-dimensional geometries. Confinement-induced resonances are suppressed due to reactions and are completely absent in the universal limit where the short-range loss probability approaches unity.

Zbigniew Idziaszek; Krzysztof Jachymski; Paul S. Julienne

2014-12-08

313

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

PubMed

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

Glossman-Mitnik, Daniel

2014-07-01

314

Patterned retarder films using reactive mesogen technology  

NASA Astrophysics Data System (ADS)

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.

Parri, Owain; Smith, Graham; Harding, Richard; Yoon, Hyun-Jin; Gardiner, Iain; Sargent, Joe; Skjonnemand, Karl

2011-03-01

315

Negative ion production in small angle scattering of highly charged ions from the (0001) surface of highly oriented pyrolytic graphite  

NASA Astrophysics Data System (ADS)

Highly charged N, O, F, and S ions, chosen for their electron affinities, were extracted from the Lawrence Livermore National Laboratory's EBIT II. After collimation, these ions struck a target of highly oriented pyrolytic graphite (HOPG) at an incident angle of 1.0 degree. Those ions scattered by 2.35 degrees (1.35 degree with respect to the surface) were charge state analyzed and the predominant charge state fractions were determined. As might be expected, there is a tendency for the fraction of negative ions to increase with increasing electron affinity; however, the negative ion yield is also strongly dependent on the ion velocity. For example, for sulfur the negative ion yields measured range from 0.13 to 0.23 of the scattered ions while for fluorine the range was 0.35 to 0.40. A pronounced velocity dependence found for the S- ions is described well by a Saha-Langmuir-type equation.

Reaves, M.; Kessel, Q. C.; Pollack, E.; Smith, W. W.; Briere, M. A.; Schneider, D. H.

1997-02-01

316

Negative ion production in small angle scattering of highly charged ions from the (0001) surface of highly oriented pyrolytic graphite  

Microsoft Academic Search

Highly charged N, O, F, and S ions, chosen for their electron affinities, were extracted from the Lawrence Livermore National Laboratory’s EBIT II. After collimation, these ions struck a target of highly oriented pyrolytic graphite (HOPG) at an incident angle of 1.0 degree. Those ions scattered by 2.35 degrees (1.35 degree with respect to the surface) were charge state analyzed

M. Reaves; Q. C. Kessel; E. Pollack; W. W. Smith; M. A. Briere; D. H. Schneider

1997-01-01

317

A new iterative method for scattering problems  

Microsoft Academic Search

A new iterative method for scattering problems is presented. This method is based on the tact that cut-off waves excited by a given source are shunted by pure reactive impedance and we consider that such waves come back to the source. This approach is applied to many scattering problems by perfectly conducting bodies and seems to be efficient, particularly in

M Azizi; H Aubert; H Baudrand

1995-01-01

318

Dynamics of inelastic and reactive gas-surface collisions  

SciTech Connect

The dynamics of inelastic and reactive collisions in atomic beam-surface scattering are presented. The inelastic scattering of hyperthermal rare gaseous atoms from three alkali halide surfaces (LiF, NaCl, GI)was studied to understand mechanical energy transfer in unreactive systems. The dynamics of the chemical reaction in the scattering of H(D) atoms from the surfaces of LIF(001) and the basal plane of graphite were also studied.

Smoliar, L.A.

1995-04-01

319

Polar molecule reactive collisions in quasi-1D systems  

NASA Astrophysics Data System (ADS)

We study polar molecule scattering in quasi-one-dimensional geometries. Elastic and reactive collision rates are computed as a function of collision energy and electric dipole moment for different confinement strengths. The numerical results are interpreted in terms of first order scattering and of adiabatic models. Universal dipolar scattering is also discussed. Our results are relevant to experiments where control of the collision dynamics through one-dimensional confinement and an applied electric field is envisioned.

Simoni, A.; Srinivasan, S.; Launay, J.-M.; Jachymski, K.; Idziaszek, Z.; Julienne, P. S.

2015-01-01

320

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

E-print Network

A measurement of the azimuthal asymmetry in dihadron production in deep-inelastic scattering of muons on transversely polarised proton (NH$_{3}$) targets are presented. They provide independent access to the transversity distribution functions through the measurement of the Collins asymmetry in single hadron production. The data were taken in the year $2010$ with the COMPASS spectrometer using a $160\\,\\mbox{GeV}/c$ muon beam of the CERN SPS, increasing by a factor of about three the available statistics of the previously published data taken in the year $2007$. The measured sizeable asymmetry is in good agreement with the published data. An approximate equality of the Collins asymmetry and the dihadron asymmetry is observed, suggesting a common physical mechanism in the underlying fragmentation.

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

2014-01-30

321

Transverse momentum dependent evolution: Matching semi-inclusive deep inelastic scattering processes to Drell-Yan and W/Z boson production  

NASA Astrophysics Data System (ADS)

We examine the QCD evolution for the transverse momentum dependent observables in hard processes of semi-inclusive hadron production in deep inelastic scattering and Drell-Yan lepton pair production in pp collisions, including the spin-average cross sections and Sivers single transverse spin asymmetries. We show that the evolution equations derived by a direct integral of the Collins-Soper-Sterman evolution kernel from low to high Q can describe well the transverse momentum distributions of the unpolarized cross sections in the Q2 range from 2 to 100GeV2. In addition, the matching is established between our evolution and the Collins-Soper-Sterman resummation with b* prescription and Konychev-Nodalsky parametrization of the nonperturbative form factors, which are formulated to describe the Drell-Yan lepton pair and W/Z boson production in hadronic collisions. With these results, we present the predictions for the Sivers single transverse spin asymmetries in Drell-Yan lepton pair production and W± boson production in polarized pp and ?-p collisions for several proposed experiments. We emphasize that these experiments will not only provide crucial test of the sign change of the Sivers asymmetry but also provide important opportunities to study the QCD evolution effects.

Sun, Peng; Yuan, Feng

2013-12-01

322

2,3,7,8-Tetrachlorodibenzo-p-dioxin Increases Reactive Oxygen Species Production in Human Endothelial Cells Via Induction of Cytochrome P4501A1  

PubMed Central

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. PMID:20171976

Kopf, PG; Walker, MK

2010-01-01

323

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

Microsoft Academic Search

Previously we showed that the polychlorinated biphenyl 3,3?,4,4?-tetrachlorobiphenyl (TCB) caused a release of reactive oxygen species (ROS) from cytochrome P450 1A (CYP1A) of the fish scup (Stenotomus chrysops), and from rat and human CYP1A1. This was linked to a TCB- and NADPH-dependent oxidative inactivation of the enzyme, which in scup and rat was inversely related to the rates of TCB

Jennifer J Schlezinger; Jennifer Keller; Lori A Verbrugge; John J Stegeman

2000-01-01

324

Induction of Spermidine\\/Spermine N 1Acetyltransferase in Human Cancer Cells in Response to Increased Production of Reactive Oxygen Species  

Microsoft Academic Search

Reactive oxygen species (ROS) are involved in a number of disease states where they are believed to be responsible for cellular damage. In this study we examined the effect of ROS generation on polyamine catabolism. Treatment of human breast cancer cells with either H2O2 or hyperoxia increased the activity of spermidine\\/spermine N1-acetyltransferase (SSAT). These increases occurred before any significant signs

Shalu Chopra; Heather M Wallace

1998-01-01

325

PROCESSING, PRODUCTS, AND FOOD SAFETY Thiobarbituric Acid Reactive Substances and Volatile Compounds in Chicken Breast Meat Infused with Plant Extracts and Subjected to Electron Beam Irradiation  

Microsoft Academic Search

The effect of irradiation on thiobarbituric acid reactive substances (TBARS) and volatile compounds in raw and cooked nonirradiated and irradiated chicken breast meat infused with green tea and grape seed extracts was investigated. Chicken breast meat was vacuum in- fused with green tea extract (3,000 ppm), grape seed ex- tract (3,000 ppm), or their combination (at a total of 6,000

T. Rababah; N. S. Hettiarachchy; R. Horax; M. J. Cho; B. Davis; J. Dickson

326

Quasielastic and inelastic neutron scattering study of the hydration of monoclinic and triclinic tricalcium silicate  

NASA Astrophysics Data System (ADS)

The hydration of Mg-stabilized triclinic and monoclinic tricalcium silicate samples were studied using quasielastic neutron scattering to follow the fixation of hydrogen into the reaction products and by applying hydration models to the data. The quantity of Ca(OH) 2 produced during hydration was also determined using inelastic neutron scattering. The monoclinic form was found to be intrinsically less reactive that the triclinic form. The monoclinic form was also confirmed to produce more product than the triclinic form after 50 h, a process found to occur through a longer, rather than earlier, nucleation and growth regime. Results indicated an increase in the permeability of the hydration layer product relative to the triclinic form and the increase in the length of the nucleation and growth regime was thus attributed to an alteration in morphology or structure of the hydration layer product, extending the time for diffusion limited mechanics to be reached.

Peterson, Vanessa K.; Brown, Craig M.; Livingston, Richard A.

2006-08-01

327

Negative ion production in small angle scattering of highly charged ions from the (0001) surface of highly oriented pyrolytic graphite  

SciTech Connect

Highly charged N, O, F, and S ions, chosen for their electron affinities, were extracted from the Lawrence Livermore National Laboratory{close_quote}s EBIT II. After collimation, these ions struck a target of highly oriented pyrolytic graphite (HOPG) at an incident angle of 1.0 degree. Those ions scattered by 2.35 degrees (1.35 degree with respect to the surface) were charge state analyzed and the predominant charge state fractions were determined. As might be expected, there is a tendency for the fraction of negative ions to increase with increasing electron affinity; however, the negative ion yield is also strongly dependent on the ion velocity. For example, for sulfur the negative ion yields measured range from 0.13 to 0.23 of the scattered ions while for fluorine the range was 0.35 to 0.40. A pronounced velocity dependence found for the S{sup {minus}} ions is described well by a Saha-Langmuir-type equation. {copyright} {ital 1997 American Institute of Physics.}

Reaves, M.; Kessel, Q.C.; Pollack, E.; Smith, W.W. [Department of Physics and The Institute of Materials Science, The University of Connecticut, Storrs, Connecticut 06269 (United States); Briere, M.A.; Schneider, D.H. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

1997-02-01

328

Water Reactive Materials  

Microsoft Academic Search

Water reactive chemicals are generally aggressive materials that are used widely in the process industries. Common water reactive substances are sulphur trioxide, oleum, titanium tetrachloride, silicon tetrachloride, chlorosulphonic acid, chloroacetyl chloride and phosphorus trichloride. When released to the atmosphere, water reactive materials generally react readily with any free ground water, substrate water and atmospheric water. The exact nature, kinetics and

L. Fernie; P. Wright; T. Kapias

2007-01-01

329

Production of reactive oxygen species by withaferin A causes loss of type collagen expression and COX-2 expression through the PI3K/Akt, p38, and JNK pathways in rabbit articular chondrocytes.  

PubMed

Withaferin A (WFA) is a major chemical constituent of Withania somnifera, also known as Indian ginseng. Many recent reports have provided evidence of its anti-tumor, anti-inflammation, anti-oxidant, and immune modulatory activities. Although the compound appears to have a large number of effects, its defined mechanisms of action have not yet been determined. We investigated the effects of WFA on loss of type collagen expression and inflammation in rabbit articular chondrocytes. WFA increased the production of reactive oxygen species, suggesting the induction of oxidative stress, in a dose-dependent manner. Also, we confirmed that WFA causes loss of type collagen expression and inflammation as determined by a decrease of type II collagen expression and an increase of cyclooxygenase-2 (COX-2) expression via western blot analysis in a dose- and time- dependent manner. WFA also reduced the synthesis of sulfated proteoglycan via Alcian blue staining and caused the synthesis of prostaglandin E2 (PGE2) via assay kit in dose- and time-dependent manners. Treatment with N-acetyl-L-cysteine (NAC), an antioxidant, inhibited WFA-induced loss of type II collagen expression and increase in COX-2 expression, accompanied by inhibition of reactive oxygen species production. WFA increased phosphorylation of both Akt and p38. Inhibition of PI3K/Akt, p38, and JNK with LY294002 (LY), SB203580 (SB), or SP600125 (SP) in WFA-treated cells rescued the expression of type II collagen and suppressed the expression of COX-2. These results demonstrate that WFA induces loss of type collagen expression and inflammation via PI3K/Akt, p38, and JNK by generating reactive oxygen species in rabbit articular chondrocytes. PMID:24016823

Yu, Seon-Mi; Kim, Song-Ja

2013-11-01

330

Parton distributions extracted from data on deep-inelastic lepton scattering, prompt photon production, and the Drell-Yan process  

NASA Astrophysics Data System (ADS)

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.

Harriman, P. N.; Martin, A. D.; Stirling, W. J.; Roberts, R. G.

1990-08-01

331

Sensitivities in the production of spread-out Bragg peak dose distributions by passive scattering with beam current modulation  

SciTech Connect

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.

Lu, H.-M.; Brett, Robert; Engelsman, Martijn; Slopsema, Roelf; Kooy, Hanne; Flanz, Jay [Francis H. Burr Proton Therapy Center, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114 (United States)

2007-10-15

332

Cleavage fragments of the third complement component (C3) enhance stromal derived factor-1 (SDF-1)-mediated platelet production during reactive postbleeding thrombocytosis  

Microsoft Academic Search

We hypothesized that the third complement component (C3) cleavage fragments (C3a and des-ArgC3a) are involved in stress\\/inflammation-related thrombocytosis, and investigated their potential role in reactive thrombocytosis induced by bleeding. We found that platelet counts are lower in C3-deficient mice in response to excessive bleeding as compared to normal littermates and that C3a and des-ArgC3a enhance stromal-derived factor-1 (SDF-1)-dependent megakaryocyte (Megs)

M Wysoczynski; M Kucia; J Ratajczak; M Z Ratajczak

2007-01-01

333

Bio-oil upgrading by means of ethyl ester production in reactive distillation to remove water and to improve storage and fuel characteristics  

Microsoft Academic Search

Several solid acids (SO42?\\/MxOy) were prepared and compared in upgrading bio-oil using ethanol and bio-oil as raw materials through reactive rectification. Two kinds of upgraded bio-oil were obtained in the upgrading process. The densities of two kinds of upgraded bio-oil were reduced from 1.16 to 0.91 and 0.95gcm?3, and the gross calorific value increased from 14.3 to 21.5 and 24.5MJkg?1

Xu Junming; Jiang Jianchun; Sun Yunjuan; Lu Yanju

2008-01-01

334

Implementation of scattering pinhole diagnostic for detection of fusion products on CR-39 at high particle fluence  

E-print Network

Many Inertial Confinement Fusion (ICF) experiments use solid-state nuclear track detector CR-39 as a means to detect different types of nuclear products. Until recently, it was difficult to use CR-39 in experiments with ...

Orozco, David, S.B. Massachusetts Institute of Technology

2014-01-01

335

Study of the photodynamic effect on the A549 cell line by atomic force microscopy and the influence of green tea extract on the production of reactive oxygen species.  

PubMed

We studied the morphology of the A549 cell line (human lung carcinoma cells) before and after photodynamic therapy (PDT) by atomic force microscopy. PDT was induced by an efficient light-emitting diode source with total light dose of 15 J cm(-2) in the presence of the sensitizer zinc-5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrine. In the presence of molecular oxygen, light activation of the photosensitizer, which accumulates in cancer cells, leads to the local production of reactive oxygen species (ROS). This is one of several reasons leading to cell death, and in some cases we could observe signs of apoptosis. We detected the kinetics of ROS production to be dependent on the presence of green tea extract. PMID:19723103

Tomankova, Katerina; Kolarova, Hana; Bajgar, Robert; Jirova, Dagmar; Kejlova, Kristina; Mosinger, Jiri

2009-08-01

336

Effects of 47C allele (rs4880) of the SOD2 gene in the production of intracellular reactive species in peripheral blood mononuclear cells with and without lipopolysaccharides induction.  

PubMed

Challenging of peripheral blood mononuclear cells (PBMCs) with lipopolysaccharides (LPS) has been shown to activate monocytes and macrophages, leading to the production of pro-inflammatory cytokines and reactive oxygen species (ROS). Manganese superoxide dismutase (MnSOD) is an important enzyme that may play a central role in the response to oxidative stress. 47C> T SNP of the SOD2 gene, the -9Val MnSOD is less efficient than the -9Ala version. We have previously characterized the cellular redox status of human PBMCs expressing either -9Ala (CC) or -9Val (TT) SOD2 and analyzed the responses of these cells to oxidative stress induced by LPS. Due to the observed alterations in the activities of these antioxidant enzymes, we decided to investigate their immunocontent and analyze the production of intracellular oxidants, as well as any resulting DNA damage. PBMCs were isolated from the blood of 30 healthy human volunteers (15 volunteers per allele). We then analyzed levels of nitrite, DNA damage by comet assay, TNF-?, carboxymethyl lysine and nitrotyrosine and assessed production of intracellular reactive species by the DCFH-DA-based assay and western blots were used to analyze protein levels. Our results show that there occurs an increase in nitric oxide production in both allele groups after challenge with LPS. A significant increase in DNA damage was observed in PBMCs after an 8-h LPS challenge. Cells expressing the SOD2 47C allele quickly adapt to a more intense metabolism by upregulating cellular detoxification mechanisms. However, when these cells are stressed over a long period, they accumulate a large quantity of toxic metabolic byproducts. PMID:24164232

Paludo, F J O; Bristot, I J; Alho, C S; Gelain, D P; Moreira, J C F

2014-02-01

337

Small angle x-ray scattering: Instrument development and studies of protein aggregation, cellulose hydrolysis, and the production of nanoporous metals using surfactact templates  

NASA Astrophysics Data System (ADS)

Small angle x-ray scattering (SAXS) was used to obtain structural insights into protein aggregation, the enzymatic hydrolysis of cellulose, and the structural evolution of surfactant-templated nanoporous palladium and platinum systems during their synthesis. SAXS is bulk technique that allows probing the nanometer-scale morphology, interactions, density, and distribution of a variety of nonperiodic systems in the solid, liquid, or gaseous state. A 10-meter Small Angle Scattering camera, originally at ORNL, was assembled. During its re-commissioning, several upgrades were made including new data acquisition software built using National Instrument's Labview development environment, as well as portability to use analysis tools in wide use in scattering community. The Multiple Energy Diffractometer Using Small, medium and wide Angles (MEDUSA) was designed and built, its development will be discussed. The ability of proteins to change their conformation in response to changes in pressure, temperature, the presence of other molecular species, and ionic concentration in the solvents they are found, is a remarkable phenomenon that allows living cells to function properly. When proteins irreversibly unfold or mis-fold and aggregate this gives rise to severely debilitating diseases such as Alzheimer's and prion diseases. Protein aggregation was measured using SAXS on aqueous solutions of bovine serum albumin, myoglobin, and cellulase enzymes. Understanding how cellulose can be broken down into fermentable sugars is an important step in the development of strategies for producing alternative energy from biomass. The enzymatic hydrolysis of cellulose was studied using both small angle neutron scattering and SAXS. One result from these investigations was finding supporting evidence that nanopores within the cellulose fibril matrix allow biologically active enzymes access to digest parts of the fibers. The production of mesoporous materials for hydrogen storage applications was explored using surfactant-templated metal systems. In this, as with many materials for possible energy storage applications, chemically stable systems with good mechanical strength, high temperature resistance, and high surface areas are desirable. Time- dependent SAXS measurements were used to study the templating of Pt and Pd metals onto a surfactant structure. The reduction of these metals was carried out using two methods, reduction with ascorbate and using hydrogen-nitrogen gas mixtures.

Banuelos, Jose Leobardo

338

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

339

Measurement of "pretzelosity" asymmetry of charged pion production in semi-inclusive deep inelastic scattering on a polarized 3He target  

NASA Astrophysics Data System (ADS)

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

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.; Muñoz Camacho, C.; Nanda, S.; Narayan, A.; Nelyubin, V.; Norum, B.; Oh, Y.; Osipenko, M.; Parno, D.; Peng, J. C.; Phillips, S. K.; Posik, M.; Puckett, A. J. R.; Qiang, Y.; Rakhman, A.; Ransome, R. D.; Riordan, S.; Saha, A.; Sawatzky, B.; Schulte, E.; Shahinyan, A.; Shabestari, M. H.; Širca, S.; Stepanyan, S.; Subedi, R.; Sulkosky, V.; Tang, L.-G.; Tobias, 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

340

Gamma ray production cross section from energetic neutron inelastic scattering for methodical improvements in planetary gamma-ray spectroscopy  

SciTech Connect

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.

Castaneda, C.M.; Gearhart, R.; Sanii, B. (California Univ., Davis, CA (United States). Crocker Nuclear Lab.); Englert, P.A.J. (San Jose State Univ., CA (United States)); Drake, D.M.; Reedy, R.C. (Los Alamos National Lab., NM (United States))

1991-01-01

341

Gamma ray production cross section from energetic neutron inelastic scattering for methodical improvements in planetary gamma-ray spectroscopy  

SciTech Connect

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.

Castaneda, C.M.; Gearhart, R.; Sanii, B. [California Univ., Davis, CA (United States). Crocker Nuclear Lab.; Englert, P.A.J. [San Jose State Univ., CA (United States); Drake, D.M.; Reedy, R.C. [Los Alamos National Lab., NM (United States)

1991-12-31

342

First OH reactivity measurements in Harvard Forest  

NASA Astrophysics Data System (ADS)

The OH reactivity provides critical insight into the HOx budget under actual atmospheric conditions, and has implications for the production of ozone and the formation of secondary organic material. Previous studies have indicated that the OH reactivity measured at field sites often exceeds model estimations, but current experiments remain inconclusive about the origin of the discrepancy between the modeled and measured OH reactivity (Lou et al., 2010). As of now there are only a limited number of atmospheric studies of total OH reactivity available, so to improve understanding of the OH reactivity more studies are needed. The first OH reactivity measurements in the northeastern United States are being performed during the summer of 2013 at Harvard Forest. Harvard forest, is located about 100 km west of the Boston metropolitan area, is one of the most intensively studied forests in North America. The main biogenic VOC emitted from Harvard Forest is isoprene followed by monoterpenes and methanol. Sampling for the OH reactivity measurements will be conducted from a 30m tall meteorological tower at the Harvard Forest site. The air is drawn into a reaction cell where the OH reactivity is determined using the Comparative Reactivity Method (Sinha et al., 2008) employing a High-Sensitivity Proton Transfer Reaction Mass Spectrometer (Lindinger et al., 1998, Hansel et al., 1998). In addition to the OH reactivity measurements, the most abundant compounds present in the air sample will be quantified using PTR-MS. The quantification of these compounds is needed to compare the theoretical calculated OH reactivity with the measured OH reactivity data. The measurements will be used to evaluate our understanding of the OH budget at Harvard Forest. References: A. Hansel, A. Jordan, C. Warneke, R. Holzinger, and W. Lindinger.: Improved Detection Limit of the Proton-transfer Reaction Mass Spectrometer: On-line Monitoring of Volatile Organic Compounds at Mixing Ratios of a Few PPTV, Rapid Commun. Mass Spectrom., 12, 871-875, (1998). W. Lindinger, A. Hansel, and A. Jordan: Proton-transfer-reaction mass spectrometry (PTR-MS): on-line monitoring of volatile organic compounds at pptv levels. Chemical Society Reviews , 27, 1998. S. Lou, F. Holland, F. Rohrer, K. Lu, B. Bohn, T. Brauers, C. C. Chang, H. Fuchs, R. Häseler, K. Kita, Y. Kondo, X. Li, M. Shao, L. Zeng, A. Wahner, Y. Zhang, W. Wang, and A. Hofzumahaus, Atmospheric OH reactivities in the Pearl River Delta - China in summer 2006: measurement and model results, Atmos. Chem. Phys., 10, 11243-11260, (2010). V. Sinha, J. Williams, J.N. Crowley, and J. Lelieveld., The Comparaptive Reactivity Methode - a new tool to measure total OH Reactivity in ambient air, Atmos. Env., 38, 2511-2522, (2008).

Herdlinger-Blatt, I. S.; Martin, S. T.; Hansel, A.; McKinney, K. A.

2013-12-01

343

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

NASA Astrophysics Data System (ADS)

Natural grasses in semiarid rangelands constitute an effective protection against soil erosion and degradation, are a source of natural food for livestock and play a critical role in the hydrologic cycle by contributing to the uptake and transpiration of water. However, natural pastures are threatened by land abandonment and the consequent encroachment of shrubs and trees as well as by changing climatic conditions. In spite of their ecological and economic importance, the 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.

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

2014-04-01

344

Reactive collisions of sulfur dioxide with molten carbonates.  

PubMed

Molecular beam scattering experiments are used to investigate reactions of SO(2) at the surface of a molten alkali carbonate eutectic at 683 K. We find that two-thirds of the SO(2) molecules that thermalize at the surface of the melt are converted to gaseous CO(2) via the reaction SO(2)(g) + CO(3)(2-) --> CO(2)(g) + SO(3)(-2). The CO(2) product is formed from SO(2) in less than 10(-6) s, implying that the reaction takes place in a shallow liquid region less than 100 A deep. The reaction probability does not vary between 683 and 883 K, further implying a compensation between decreasing SO(2) residence time in the near-interfacial region and increasing reactivity at higher temperatures. These results demonstrate the remarkable efficiency of SO(2) --> CO(2) conversion by molten carbonates, which appear to be much more reactive than dry calcium carbonate or wet slurries commonly used for flue gas desulfurization in coal-burning power plants. PMID:20133648

Krebs, Thomas; Nathanson, Gilbert M

2010-04-13

345

Design of weak scattering media for controllable light scattering.  

PubMed

We explore the possibility of designing correlation functions of a particle's scattering potential for producing desired scattered intensity distributions, within the validity of the first Born and far-field approximations. It is shown that for scatterers with the same average distributions of the scattering potential (refractive index) but different degrees of potential's correlation, the scattered fields with prescribed average intensity distributions can be produced. Two examples of such potentials are included: those for flat circular and ring-like scattered intensities, if considered to be a function of the scattering (azimuthal) angle. In both cases the height, width and edge sharpness can be adjusted at will. Production of the novel media is envisioned via the 3D printing or sequences of liquid crystal light modulators. PMID:25679865

Korotkova, Olga

2015-01-15

346

Sublethal concentrations of salicylic acid decrease the formation of reactive oxygen species but maintain an increased nitric oxide production in the root apex of the ethylene-insensitive never ripe tomato mutants.  

PubMed

The pattern of salicylic acid (SA)-induced production of reactive oxygen species (ROS) and nitric oxide (NO) were different in the apex of adventitious roots in wild-type and in the ethylene-insensitive never ripe (Nr) mutants of tomato (Solanum lycopersicum L. cv Ailsa Craig). ROS were upregulated, while NO remained at the control level in apical root tissues of wildtype plants exposed to sublethal concentrations of SA. In contrast, Nr plants expressing a defective ethylene receptor displayed a reduced level of RO S and a higher NO content in the apical root cells. In wild-type plants NO production seems to be RO S(H2O2)-dependent at cell death-inducing concentrations of SA, indicating that ROS and NO may interact to trigger oxidative cell death. In the absence of significant RO S accumulation, the increased NO production caused moderate reduction in cell viability in root apex of Nr plants exposed to 10(-3) M SA. This suggests that a functional ethylene signaling pathway is necessary for the control of ROS and NO production induced by SA. PMID:21847015

Tari, Irma; Poór, Péter; Gémes, Katalin

2011-09-01

347

Hydrothermal Reactivity of Amines  

NASA Astrophysics Data System (ADS)

The reactivity of aqueous amines depends on temperature, pH, and redox state [1], all of which are highly variable in hydrothermal systems. Temperature and pH affect the ratio of protonated to unprotonated amines (R-NH2 + H+ = R-NH3+), which act as nucleophiles and electrophiles, respectively. We hypothesize that this dual nature can explain the pH dependence of reaction rates, and predict that rates will approach a maximum at pH = pKa where the ratio of protonated and unprotonated amines approaches one and the two compounds are poised to react with one another. Higher temperatures in hydrothermal systems allow for more rapid reaction rates, readily reversible reactions, and unique carbon-nitrogen chemistry in which water acts as a reagent in addition to being the solvent. In this study, aqueous benzylamine was used as a model compound to explore the reaction mechanisms, kinetics, and equilibria of amines under hydrothermal conditions. Experiments were carried out in anoxic silica glass tubes at 250°C (Psat) using phosphate-buffered solutions to observe changes in reaction rates and product distributions as a function of pH. The rate of decomposition of benzylamine was much faster at pH 4 than at pH 9, consistent with the prediction that benzylamine acts as both nucleophile and an electrophile, and our estimate that the pKa of benzylamine is ~5 at 250°C and Psat. Accordingly, dibenzylamine is the primary product of the reaction of two benzylamine molecules, and this reaction is readily reversible under hydrothermal conditions. Extremely acidic or basic pH can be used to suppress dibenzylamine production, which also suppresses the formation of all other major products, including toluene, benzyl alcohol, dibenzylimine, and tribenzylamine. This suggests that dibenzylamine is the lone primary product that then itself reacts as a precursor to produce the above compounds. Analog experiments performed with ring-substituted benzylamine derivatives and chiral methylbenzylamine suggest an SN2 mechanism for the formation of dibenzylamine. These results show the interdependence of pH and speciation with amine reaction rates. We predict the distribution of primary, secondary, tertiary, and quaternary amines in hydrothermal solutions can be used to solve for the pH of subsurface reaction zones in hydrothermal systems. [1] McCollom, T.M. (2013) The influence of minerals on decomposition of the n-alkyl-?-amino acid norvaline under hydrothermal conditions. Geochim. Cosmochim. Acta, 104, 330-357.

Robinson, K.; Shock, E.; Hartnett, H. E.; Williams, L. B.; Gould, I.

2013-12-01

348

Hazard Analysis for the High Power Accelerator Production of Tritium (APT) Experiments at the Los Alamos Neutron Scattering Center (LANSCE).  

SciTech Connect

The Accelerator Production of Tritium (APT) Target/Blanket and Materials Engineering Demonstration and Development (ED and D) Project has undertaken a major program of high-power materials irradiation at the Los Alamos Neutron Science Center (LANSCE) Accelerator. Five experiments have been installed in the Target A-6 area, immediately before the Isotope Production facility and the LANSCE bearnstop, where they will take a 1.0-mAmp-proton beam for up to 10 months. This operation is classed as a Nuclear Category (cat)-3 activity, since enough radionuclides buildup in the path of tie beam to exceed cat-3 threshold quantities. In the process of analyzing this buildup, it was realized that a loss of coolant accident (LOCA) could result in oxidation and subsequent vaporization of certain tungsten elements contained in our experiments. If this process occurs in the presence of steam, breakup of the water molecule would also provide a potentially explosive source of hydrogen, causing maximum release of radioactive aerosols to the surrounding environment. This process can occur in a matter of seconds. Such a release would result in potentially unacceptable dose to the public at the LANSCE site boundary, 800 meters from the A-6 area.

Waters, L.S.

1999-06-08

349

Withaferin A-caused production of intracellular reactive oxygen species modulates apoptosis via PI3K/Akt and JNKinase in rabbit articular chondrocytes.  

PubMed

Withaferin A (WFA) is known as a constituent of Ayurvedic medicinal plant, Withania somnifera, and has been used for thousands of years. Although WFA has been used for the treatment of osteoarthritis (OA) and has a wide range of biochemical and pharmacologic activities, there are no findings suggesting its properties on chondrocytes or cartilage. The aim of the present study is to investigate the effects of WFA on apoptosis with focus on generation of intracellular reactive oxygen species (ROS). Here we showed that WFA significantly increased the generation of intracellular ROS in a dose-dependent manner. We also determined that WFA markedly leads to apoptosis as evidenced by accumulation of p53 by Western blot analysis. N-Acetyl-L-Cystein (NAC), an antioxidant, prevented WFA-caused expression of p53 and inhibited apoptosis of chondrocytes. We also found that WFA causes the activation of PI3K/Akt and JNKinase. Inhibition of PI3K/Akt and JNKinase with LY294002 (LY)/triciribine (TB) or SP600125 (SP) in WFA-treated cells reduced accumulation of p53 and inhibited fragmented DNA. Our findings suggested that apoptosis caused by WFA-induced intracellular ROS generation is regulated through PI3K/Akt and JNKinase in rabbit articular chondrocytes. PMID:25120312

Yu, Seon-Mi; Kim, Song-Ja

2014-08-01

350

Withaferin A-Caused Production of Intracellular Reactive Oxygen Species Modulates Apoptosis via PI3K/Akt and JNKinase in Rabbit Articular Chondrocytes  

PubMed Central

Withaferin A (WFA) is known as a constituent of Ayurvedic medicinal plant, Withania somnifera, and has been used for thousands of years. Although WFA has been used for the treatment of osteoarthritis (OA) and has a wide range of biochemical and pharmacologic activities, there are no findings suggesting its properties on chondrocytes or cartilage. The aim of the present study is to investigate the effects of WFA on apoptosis with focus on generation of intracellular reactive oxygen species (ROS). Here we showed that WFA significantly increased the generation of intracellular ROS in a dose-dependent manner. We also determined that WFA markedly leads to apoptosis as evidenced by accumulation of p53 by Western blot analysis. N-Acetyl-L-Cystein (NAC), an antioxidant, prevented WFA-caused expression of p53 and inhibited apoptosis of chondrocytes. We also found that WFA causes the activation of PI3K/Akt and JNKinase. Inhibition of PI3K/Akt and JNKinase with LY294002 (LY)/triciribine (TB) or SP600125 (SP) in WFA-treated cells reduced accumulation of p53 and inhibited fragmented DNA. Our findings suggested that apoptosis caused by WFA-induced intracellular ROS generation is regulated through PI3K/Akt and JNKinase in rabbit articular chondrocytes. Graphical Abstract PMID:25120312

2014-01-01

351

Direct mitochondrial dysfunction precedes reactive oxygen species production in amiodarone-induced toxicity in human peripheral lung epithelial HPL1A cells  

SciTech Connect

Amiodarone (AM), a drug used in the treatment of cardiac dysrrhythmias, can produce severe pulmonary adverse effects, including fibrosis. Although the pathogenesis of AM-induced pulmonary toxicity (AIPT) is not clearly understood, several hypotheses have been advanced, including increased inflammatory mediator release, mitochondrial dysfunction, and free-radical formation. The hypothesis that AM induces formation of reactive oxygen species (ROS) was tested in an in vitro model relevant for AIPT. Human peripheral lung epithelial HPL1A cells, as surrogates for target cells in AIPT, were susceptible to the toxicity of AM and N-desethylamiodarone (DEA), a major AM metabolite. Longer incubations ({>=} 6 h) of HPL1A cells with 100 {mu}M AM significantly increased ROS formation. In contrast, shorter incubations (2 h) of HPL1A cells with AM resulted in mitochondrial dysfunction and cytoplasmic cytochrome c translocation. Preexposure of HPL1A cells to ubiquinone and {alpha}-tocopherol was more effective than that with Trolox C (registered) or 5,5-dimethylpyrolidine N-oxide (DMPO) at preventing AM cytotoxicity. These data suggest that mitochondrial dysfunction, rather than ROS overproduction, represents an early event in AM-induced toxicity in peripheral lung epithelial cells that may be relevant for triggering AIPT, and antioxidants that target mitochondria may potentially have beneficial effects in AIPT.

Nicolescu, Adrian C. [Department of Pharmacology and Toxicology, Queen's University, Kingston, ON, K7L 3N6 (Canada)], E-mail: adrian.nicolescu@ualberta.ca; Ji, Yanbin; Comeau, Jeannette L. [Department of Pharmacology and Toxicology, Queen's University, Kingston, ON, K7L 3N6 (Canada); Hill, Bruce C. [Department of Biochemistry, Queen's University, Kingston, ON, K7L 3N6 (Canada); Takahashi, Takashi [Division of Molecular Carcinogenesis, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Brien, James F.; Racz, William J.; Massey, Thomas E. [Department of Pharmacology and Toxicology, Queen's University, Kingston, ON, K7L 3N6 (Canada)

2008-03-15

352

Inhibition of NADPH cytochrome P450 reductase by the model sulfur mustard vesicant 2-chloroethyl ethyl sulfide is associated with increased production of reactive oxygen species  

SciTech Connect

Inhalation of vesicants including sulfur mustard can cause significant damage to the upper airways. This is the result of vesicant-induced modifications of proteins important in maintaining the integrity of the lung. Cytochrome P450s are the major enzymes in the lung mediating detoxification of sulfur mustard and its metabolites. NADPH cytochrome P450 reductase is a flavin-containing electron donor for cytochrome P450. The present studies demonstrate that the sulfur mustard analog, 2-chloroethyl ethyl sulfide (CEES), is a potent inhibitor of human recombinant cytochrome P450 reductase, as well as native cytochrome P450 reductase from liver microsomes of saline and {beta}-naphthoflavone-treated rats, and cytochrome P450 reductase from type II lung epithelial cells. Using rat liver microsomes from {beta}-naphthoflavone-treated rats, CEES was found to inhibit CYP 1A1 activity. This inhibition was overcome by microsomal cytochrome P450 reductase from saline-treated rats, which lack CYP 1A1 activity, demonstrating that the CEES inhibitory activity was selective for cytochrome P450 reductase. Cytochrome P450 reductase also generates reactive oxygen species (ROS) via oxidation of NADPH. In contrast to its inhibitory effects on the reduction of cytochrome c and CYP1A1 activity, CEES was found to stimulate ROS formation. Taken together, these data demonstrate that sulfur mustard vesicants target cytochrome P450 reductase and that this effect may be an important mechanism mediating oxidative stress and lung injury.

Gray, Joshua P. [Department of Science, United States Coast Guard Academy, New London, CT (United States); Department of Pharmacology and Toxicology, Rutgers University, Piscataway, NJ (United States); Mishin, Vladimir [Department of Pharmacology and Toxicology, Rutgers University, Piscataway, NJ (United States); Heck, Diane E. [Department of Environmental Health Science, New York Medical College, Valhalla, NY (United States); Laskin, Debra L. [Department of Pharmacology and Toxicology, Rutgers University, Piscataway, NJ (United States); Laskin, Jeffrey D., E-mail: jlaskin@eohsi.rutgers.ed [Environmental and Occupational Medicine, UMDNJ-Robert Wood Johnson Medical School, Piscataway, NJ (United States)

2010-09-01

353

Major Components of Energy Drinks (Caffeine, Taurine, and Guarana) Exert Cytotoxic Effects on Human Neuronal SH-SY5Y Cells by Decreasing Reactive Oxygen Species Production  

PubMed Central

Scope. To elucidate the morphological and biochemical in vitro effects exerted by caffeine, taurine, and guarana, alone or in combination, since they are major components in energy drinks (EDs). Methods and Results. On human neuronal SH-SY5Y cells, caffeine (0.125–2?mg/mL), taurine (1–16?mg/mL), and guarana (3.125–50?mg/mL) showed concentration-dependent nonenzymatic antioxidant potential, decreased the basal levels of free radical generation, and reduced both superoxide dismutase (SOD) and catalase (CAT) activities, especially when combined together. However, guarana-treated cells developed signs of neurite degeneration in the form of swellings at various segments in a beaded or pearl chain-like appearance and fragmentation of such neurites at concentrations ranging from 12.5 to 50?mg/mL. Swellings, but not neuritic fragmentation, were detected when cells were treated with 0.5?mg/mL (or higher doses) of caffeine, concentrations that are present in EDs. Cells treated with guarana also showed qualitative signs of apoptosis, including membrane blebbing, cell shrinkage, and cleaved caspase-3 positivity. Flow cytometric analysis confirmed that cells treated with 12.5–50?mg/mL of guarana and its combinations with caffeine and/or taurine underwent apoptosis. Conclusion. Excessive removal of intracellular reactive oxygen species, to nonphysiological levels (or “antioxidative stress”), could be a cause of in vitro toxicity induced by these drugs. PMID:23766861

Zeidán-Chuliá, Fares; Kolling, Eduardo Antônio; Rybarczyk-Filho, José Luiz; Ambrosi, Priscilla; Resende Terra, Silvia; Pires, André Simões; da Rocha, João Batista Teixeira; Antônio Behr, Guilherme; Fonseca Moreira, José Cláudio

2013-01-01

354

Bendamustine and melphalan kill myeloma cells similarly through reactive oxygen species production and activation of the p53 pathway and do not overcome resistance to each other.  

PubMed

Because the old alkylating drug bendamustine (BDM) is currently under evaluation in patients with multiple myeloma, we compared its efficacy to that of melphalan in 29 human myeloma cell lines (HMCLs). The concentrations of BDM and melphalan that killed 50% of cells (LD50) in HMCLs were linearly correlated (p < 0.001), and reactive oxygen (ROS) scavengers similarly inhibited cell death induced by both drugs. Sensitivity of HMCLs to both drugs was correlated to p53: the BDM and melphalan median LD50 values of TP53(wild-type) HMCLs were more than two-fold lower than those of TP53(abnormal) HMCLs (p < 0.001), and p53 silencing in TP53(wt) NCI-H929 cells inhibited BDM- and melphalan-induced cell death. Both drugs induced expression of p53 targets, p21, Puma and DR5, only in TP53(wt) HMCLs. In primary cells, both drugs induced an increase in DR5 expression in cells without del(17p). Finally, we demonstrated that the combined effect of BDM and melphalan was additive, and that BDM did not overcome melphalan resistance and vice versa. PMID:24308434

Surget, Sylvanie; Lemieux-Blanchard, Emilie; Maïga, Sophie; Descamps, Géraldine; Le Gouill, Steven; Moreau, Philippe; Amiot, Martine; Pellat-Deceunynck, Catherine

2014-09-01

355

Antiplatelet effect of phloroglucinol is related to inhibition of cyclooxygenase, reactive oxygen species, ERK/p38 signaling and thromboxane A{sub 2} production  

SciTech Connect

Platelet dysfunction is a major risk factor of cardiovascular diseases such as atherosclerosis, stroke and myocardial infarction. Many antiplatelet agents are used for prevention and treatment of these diseases. In this study, phloroglucinol (2.5–25 ?M) suppressed AA-induced platelet aggregation and thromboxane B{sub 2} (TXB{sub 2}) production, but not U46619-induced platelet aggregation. Phloroglucinol (100–250 ?M) showed little cytotoxicity to platelets. Phloroglucinol inhibited the COX-1 and COX-2 activities by 45–74% and 49–72% respectively at concentrations of 10–50 ?M. At concentrations of 1 and 5 ?M, phloroglucinol attenuated the AA-induced ROS production in platelets by 30% and 53%, with an IC{sub 50} of 13.8 ?M. Phloroglucinol also inhibited the PMA-stimulated ROS production in PMN. Preincubation of platelets by phloroglucinol (10–25 ?M) markedly attenuated the AA-induced ERK and p38 phosphorylation. Intravenous administration of phloroglucinol (2.5 and 5 ?mol/mouse) suppressed the ex vivo AA-induced platelet aggregation by 57–71%. Phloroglucinol administration also elevated the mice tail bleeding time. Moreover, phloroglucinol inhibited the IL-1?-induced PGE{sub 2} production in pulp fibroblasts. These results indicate that antiplatelet and anti-inflammatory effects of phloroglucinol are related to inhibition of COX, ROS and TXA2 production as well as ERK/p38 phosphorylation in platelets. Phloroglucinol further suppress PMA-induced ROS production in PMN. The antiplatelet effect of phloroglucinol was confirmed by ex vivo study. Clinically, the consumption of phloroglucinol-containing food/natural products as nutritional supplement may be helpful to cardiovascular health. Phloroglucinol has potential pharmacological use. -- Highlights: ? Phloroglucinol suppressed AA-induced platelet aggregation and thromboxane production. ? Phloroglucinol inhibited COX activity and IL-1b-induced PGE2 production in fibroblast. ? Phloroglucinol declined platelet and PMN ROS production and ERK/p38 phosphorylation. ? Phloroglucinol suppressed ex vivo AA-induced platelet aggregation. ? Phloroglucinol may prevent and for treatment of atherosclerosis/ vascular diseases.

Chang, Mei-Chi [Biomedical Science Team, Chang Gung University of Science and Technology, Taoyuan, Taiwan (China)] [Biomedical Science Team, Chang Gung University of Science and Technology, Taoyuan, Taiwan (China); Chang, Hsiao-Hua [Laboratory of Pharmacology and Toxicology, School of Dentistry and Department of Dentistry, National Taiwan University Hospital and National Taiwan University Medical College, Taipei, Taiwan (China)] [Laboratory of Pharmacology and Toxicology, School of Dentistry and Department of Dentistry, National Taiwan University Hospital and National Taiwan University Medical College, Taipei, Taiwan (China); Chan, Chiu-Po [Department of Dentistry, Chang Gung Memorial Hospital and Chang Gung University, Taipei, Taiwan (China)] [Department of Dentistry, Chang Gung Memorial Hospital and Chang Gung University, Taipei, Taiwan (China); Chou, Han-Yi; Chang, Bei-En [Graduate Institute of Oral Biology, National Taiwan University Medical College, Taipei, Taiwan (China)] [Graduate Institute of Oral Biology, National Taiwan University Medical College, Taipei, Taiwan (China); Yeung, Sin-Yuet [Department of Dentistry, Chang Gung Memorial Hospital and Chang Gung University, Taipei, Taiwan (China)] [Department of Dentistry, Chang Gung Memorial Hospital and Chang Gung University, Taipei, Taiwan (China); Wang, Tong-Mei [Laboratory of Pharmacology and Toxicology, School of Dentistry and Department of Dentistry, National Taiwan University Hospital and National Taiwan University Medical College, Taipei, Taiwan (China)] [Laboratory of Pharmacology and Toxicology, School of Dentistry and Department of Dentistry, National Taiwan University Hospital and National Taiwan University Medical College, Taipei, Taiwan (China); Jeng, Jiiang-Huei, E-mail: jhjeng@ntu.edu.tw [Laboratory of Pharmacology and Toxicology, School of Dentistry and Department of Dentistry, National Taiwan University Hospital and National Taiwan University Medical College, Taipei, Taiwan (China)] [Laboratory of Pharmacology and Toxicology, School of Dentistry and Department of Dentistry, National Taiwan University Hospital and National Taiwan University Medical College, Taipei, Taiwan (China)

2012-09-15

356

Polyethylene glycol-coated graphene oxide attenuates antigen-specific IgE production and enhanced antigen-induced T-cell reactivity in ovalbumin-sensitized BALB/c mice  

PubMed Central

Background Graphene oxide (GO) is a promising nanomaterial for potential application in the versatile field of biomedicine. Graphene-based nanomaterials have been reported to modulate the functionality of immune cells in culture and to induce pulmonary inflammation