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Sample records for 16o induced reactions

  1. Pion-induced nucleon knockout reactions on 16O and 18O

    NASA Astrophysics Data System (ADS)

    Piasetzky, E.; Altman, A.; Lichtenstadt, J.; Yavin, A. I.; Ashery, D.; Bertl, W.; Felawka, L.; Walter, H. K.; Schlepütz, F. W.; Powers, K. J.; Winter, R. G.; Pluym, J. V. D.

    1982-12-01

    The (π+, π+p), (π-, π-p), and (π-, π-n) reactions on 16O and 18O were studied at 165 MeV by coincidence measurements of the outgoing particles. The cross sections for the (π-, π-n) reaction is larger on 18O than on 16O, whereas those for the (π+, π+p) and the (π-, π-p) reactions are smaller, most likely because of the coupling between the absorption and the scattering channels. NUCLEAR REACTIONS (π+/-, π+/-p) (π-, π-n) coin. Measurements on 16O18O E=165 MeV; deduced coupling between the absorption and the scattering channels.

  2. Systematic study of pre-equilibrium emission at low energies in 12C- and 16O-induced reactions

    NASA Astrophysics Data System (ADS)

    Sharma, Manoj Kumar; Singh, Pushendra P.; Singh, Devendra P.; Yadav, Abhishek; Sharma, Vijay Raj; Bala, Indu; Kumar, Rakesh; Unnati, Singh, B. P.; Prasad, R.

    2015-01-01

    Background: The role of pre-equilibrium emission within the heavy-ion fusion process has not been fully characterized. An accurate description of this process is important for understanding the formation of the compound nucleus in fusion reactions. Purpose: We develop a systematic description, based on experimental measurements, of the strength of the pre-equilibrium process in heavy-ion fusion reactions. Method: With a view to study pre-equilibrium emission process, the excitation functions for some neutron emission channels occurring in the fusion of 12C with 128Te and 169Tm, and of 16O with 159Tb,169Tm, and 181Ta, respectively, have been measured at incident energies from near the Coulomb barrier to ≈7 MeV/nucleon. The off-line γ -ray spectrometry-based activation technique has been used for the measurements of excitation functions. The measured excitation functions have been compared with theoretical predictions based on pure statistical model code pace4 and Geometry Dependent Hybrid (GDH)-based code alice-91. The strength of pre-equilibrium emission has also determined from comparison of the experimental excitation functions and the pace4 calculations. Results: The measured excitation functions are satisfactorily reproduced by the pace4 calculations in the energy region up to the peak position. However, at relatively higher energies, the enhancement of experimental cross sections in the tail portion of excitation functions as compared to the theoretical predictions of code pace4 has been observed. The observed deviation may be attributed to the pre-equilibrium emission of particles during the thermalization of the compound nucleus. Further, alice-91 calculations which include PE emission satisfactorily reproduce the experimental data even at higher energies, indicating the significant contribution of pre-equilibrium emissions. Conclusions: Analysis of data clearly indicates that pre-equilibrium emission is an important reaction mechanism even at low

  3. Proton-helium correlation in 94 MeV/nucleon sup 16 O-induced reactions on Al, Ni, and Au targets

    SciTech Connect

    Badala, A.; Barbera, R.; Palmeri, A.; Pappalardo, G.S. ); Riggi, F. ); Bizard, G.; Durand, D.; Laville, J.L. )

    1992-04-01

    Azimuthal distributions of helium ions have been measured in coincidence with high-energy protons in reactions induced by {sup 16}O at 94 MeV/nucleon on {sup 27}Al, {sup 58}Ni, and {sup 197}Au. Helium ions have been detected in a large area multidetector. Protons have been observed at 90{degree}. Mean multiplicities of light charged particles (H and He) are found slightly dependent on the target mass. Strong azimuthal asymmetries whose intensity is larger for the Al target and vanishes with the increasing of the target mass are observed in the He distributions. Experimental data are discussed in the framework of the participant-spectator picture of a modified fireball model, taking into account intermediate energy corrections. In this framework the behavior of the azimuthal asymmetries, as a function of the target mass, indicates a strong final-state interaction between participant and spectator fragments. Such a result is found in agreement with interaction time predictions of a microscopical calculation based on the Boltzmann-Nordheim-Vlasov equation.

  4. Indirect Study of the 16O+16O Fusion Reaction Toward Stellar Energies by the Trojan Horse Method

    NASA Astrophysics Data System (ADS)

    Hayakawa, S.; Spitaleri, C.; Burtebayev, N.; Aimaganbetov, A.; Figuera, P.; Fisichella, M.; Guardo, G. L.; Igamov, S.; Indelicato, I.; Kiss, G.; Kliczewski, S.; La Cognata, M.; Lamia, L.; Lattuada, M.; Piasecki, E.; Rapisarda, G. G.; Romano, S.; Sakuta, S. B.; Siudak, R.; Trzcińska, A.; Tumino, A.; Urkinbayev, A.

    2016-05-01

    The 16O+16O fusion reaction is important in terms of the explosive oxygen burning process during late evolution stage of massive stars as well as understanding of the mechanism of low-energy heavy-ion fusion reactions. We aim to determine the excitation function for the most major exit channels, α+28Si and p+31P, toward stellar energies indirectly by the Trojan Horse Method via the 16O(20Ne, α28Si)α and 16O(20Ne, p31P)α three-body reactions. We report preliminary results involving reaction identification, and determination of the momentum distribution of α-16O intercluster motion in the projectile 20Ne nucleus.

  5. Statistical and microscopic description of energetic products in the reactions induced by sup 16 O on sup 27 Al, sup 58 Ni, and sup 197 Au at 94 MeV/nucleon

    SciTech Connect

    Badala, A.; Barbera, R.; Bonasera, A. ); Di Toro, M. Dipartimento di Fisica, Universita di Catania, Corso Italia 57, I-95129 Catania ); Palmeri, A.; Pappalardo, G.S. ); Riggi, F.; Russo, G. Dipartimento di Fisica, Universita di Catania, Corso Italia 57, I-95129 Catania ); Bizard, G.; Durand, D.; Laville, J.L. )

    1991-01-01

    Protons and charged pions have been detected at 70{degree}, 90{degree}, and 120{degree} in the reaction induced by {sup 16}O on various targets at 94 MeV/nucleon incident energy. Measured energy spectra are analyzed in terms of statistical emission from equilibrated sources in a participant-spectator picture. Microscopic dynamical calculations based on the Boltzmann-Nordheim-Vlasov equation are also performed. Experimental data are well reproduced by both models.

  6. New determination of 12C(α,γ)16O reaction rate

    NASA Astrophysics Data System (ADS)

    Oulebsir, N.

    2015-12-01

    The reaction 12C(α,γ)16O was investigated through the direct α-transfer reaction (7Li,t) at 28 and 34 MeV incident energies. We determined the reduced α-widths of the sub-threshold 2+ and 1- states of 16O from the DWBA analysis of the transfer reaction 12C(7Li,t)16O performed at two incident energies. The obtained result for the 2+ and 1- sub-threshold resonances as introduced in the R-matrix fitting of radiative capture and elastic-scattering data to determine the E2 and E1 S-factor from 0.01MeV to 4.2MeV in the center-of-mass energy. After determining the astrophysic factor of 12C(α,γ)16O S(E) with Pierre Descouvement code, I determined numerically the new reaction rate of this reaction at a different stellar temperature (0.06 Gk-2 GK). The 12C(α,γ)16O reaction rate at T9 = 0.2 is [7.21-2.25+2.15] × 10-15 cm3 s-1 mol-1. Some comparisons and discussions about our new 12C(α,γ)16O reaction rate are presented. The agreements of the reaction rate below T9 = 2 between our results and with those proposed by NACRE indicate that our results are reliable, and they could be included in the astrophysical reaction rate network.

  7. STUDY OP THE 12C(α, γ)16O REACTION BY BREAKUP OF A 16O -BEAM AT 100 MeV/A

    NASA Astrophysics Data System (ADS)

    Tatischeff, V.; Kiener, J.; Aguer, P.; Angulo-Perez, C.; Bogaert, G.; Coc, A.; Disdier, D.; Ichihara, T.; Kraus, L.; Lefebvre, A.; Linck, I.; Mittig, W.; Motobayashi, T.; Oliveira, F.; Roussel-Chomaz, P.; Stephan, C.; Thibaud, J. P.

    We present some preliminary calculations on cross sections for the breakup of 16O around 100 MeV/A with emphasis on the effect of nuclear breakup on the angular distributions. Underlying the results of these calculations, the possibilities and problems of extracting the astrophysical S-factor for the 12C(α, γ)16O reaction at very low energies are discussed. Some considerations on the experimental conditions for a 16O breakup experiment aiming at this astrophysical information, are given.

  8. Isotopic effects in the ( π±, 2N) reactions on 16O and 18O

    NASA Astrophysics Data System (ADS)

    Altman, A.; Ashery, D.; Piasetzky, E.; Lichtenstadt, J.; Yavin, A. I.; Bertl, W.; Felawka, L.; Walter, H. K.; Powers, R. J.; Winter, R. G.; v. d. Pluym, J.

    1984-09-01

    The ( π+, 2p), ( π+, pn) and ( π-, pn) reactions on 16O and 18O were studied at 165 MeV. The cross section for the ( π+, 2p) reaction on 18O is larger than that for 16O be only 5% ± 3%, while the total π+ absorption cross section is larger by 17% ± 5%. This supports the assumption that two-nucleon absorption occurs mainly on nucleons in the same shell. It is further concluded that Δ++n → pp is not only absorption mechanism that couples strongly to the nucleon knock out reactions.

  9. Cross Section Measurements of 12C+16O Fusion Reaction at Stellar Energies

    NASA Astrophysics Data System (ADS)

    Tan, Wanpeng; Fang, X.; Beard, M.; Gilardy, G.; Jung, H.; Liu, Q.; Lyons, S.; Robertson, D.; Setoodehnia, K.; Seymour, C.; Stech, E.; Vande Kolk, B.; Wiescher, M.; de Souza, R.; Hudan, S.; Singh, V.; Tang, X.; Uberseder, E.

    2016-09-01

    12C+16O is one of the three fusion reactions (12C+12C, 12C+16O, and 16O+16O) that play an important role at the late stage of stellar evolution in massive stars. The previous meassurements of its cross section at low energies rely on the singles measurements of either gamma rays or charged particles. New measurement was conducted for the 12C+16O reaction at Ecm = 3.64 - 4.93 MeV with the detection of both gammas and charged particles using the high intensity St ANA accelerator at the University of Notre Dame. The protons and alphas from the fusion evaporation were measured by a large area silicon strip detector array (SAND) while the gamma rays were detected by one large volume HPGe detector right after the target. Statistical model calculation were employed to interpret the experimental results. This provided a more reliable extrapolation for the 12C+16O fusion cross section, reducing substantially the uncertainty for stellar model simulations. This work was supported by the National Science Foundation through Grant Numbers PHY-1068192 and PHY-1419765 and the Joint Institute for Nuclear Astrophysics under Grant No. PHY-0822648.

  10. Multichannel study of the {sup 13}C({alpha},n){sup 16}O and {sup 16}O(n,{gamma}){sup 17}O reactions

    SciTech Connect

    Dufour, M.; Descouvemont, P.

    2005-07-01

    The {sup 13}C({alpha},n){sup 16}O reaction is investigated in a microscopic two-cluster model with an effective interaction recently developed for transfer reactions. The wave functions are defined in the generator coordinate method. The basis includes all {sup 13}C+{alpha} and {sup 16}O+n channels with {sup 13}C and {sup 16}O described in the p shell. Particle-hole excitations in the sd shell are also taken into account in order to include the {sup 16}O(3{sup -})+n channel. The {sup 17}O spectroscopy is in good agreement with experiment. In particular, the width of the astrophysically relevant 1/2{sub 2}{sup +} state is well reproduced ({gamma}=121 keV as compared to the experimental value {gamma}=124{+-}12 keV). The calculation of the {sup 13}C({alpha},n){sup 16}O S factor shows the importance of the 3/2{sub 3}{sup +} resonance, and provides S(0.2 MeV)=2.1x10{sup 6} MeV b, slightly lower than the NACRE recommended value (2.5x10{sup 6} MeV b). The same model is applied to the {sup 16}O(n,{gamma}){sup 17}O radiative-capture reaction at thermal and astrophysical energies.

  11. Two-neutron stripping in ({sup 18}O, {sup 16}O) and (t,p) reactions

    SciTech Connect

    Cavallaro, M.; Agodi, A.; Carbone, D.; Cunsolo, A.; Bondì, M.; Cappuzzello, F.; Nicolosi, D.; Tropea, S.; Borello-Lewin, T.; Rodrigues, M. R. D.; De Napoli, M.; Garcia, V. N.

    2014-11-11

    The {sup 12}C({sup 18}O,{sup 16}O){sup 14}C reactions has been investigated at 84 MeV incident energy. The charged ejectiles produced in the reaction have been momentum analyzed and identified by the MAGNEX magnetic spectrometer. Q-value spectra have been extracted with an energy resolution of 160 keV (Full Width at Half Maximum) and several known bound and resonant states of {sup 14}C have been identified up to 15 MeV. In particular, excited states with dominant 2p - 4h configuration are the most populated. The absolute values of the cross sections have been extracted showing a striking similarity with those measured for the same transitions by (t,p) reactions. This indicates that the effect of the {sup 16}O core is negligible in the reaction mechanism.

  12. Cross sections for proton induced high energy γ -ray emission (PIGE) in reaction 19 F(p, αγ)16 O at incident proton energies between 1.5 and 4 MeV

    NASA Astrophysics Data System (ADS)

    Cabanelas, P.; Cruz, J.; Fonseca, M.; Henriques, A.; Lourenço, F.; Luís, H.; Machado, J.; Pires Ribeiro, J.; Sánchez-Benítez, A. M.; Teubig, P.; Velho, P.; Zarza-Moreno, M.; Galaviz, D.; Jesus, A. P.

    2016-08-01

    We have studied the high energy gamma-rays produced in the reaction 19 F(p, αγ)16 O for incident proton energies from 1.5 to 4.0 MeV over NaF/Ag and CaF2/Ag thin targets in two different sets of data. Gamma-rays were detected with a High Purity Ge detector with an angle of 130° with respect to the beam axis. The cross-sections for the high energy gamma-rays of 6.129, 6.915 and 7.115 MeV have been measured for the whole group between 5 and 7.2 MeV with accuracy better than 10%. A new energy range was covered and more points are included in the cross-sections data base expanding the existing set of data. Results are in agreement with previous measurements in similar conditions.

  13. Breakup of the projectile in [sup 16]O-induced reactions on [sup 27]Al, [sup 58]Ni, and [sup 197]Au targets around 100 MeV/nucleon

    SciTech Connect

    Badala, A.; Barbera, R.; Palmeri, A.; Pappalardo, G.S. ); Riggi, F. Dipartimento di Fisica dell'Universita di Catania, Corso Italia 57, 95129 Catania )

    1993-08-01

    The spatial correlation among the four He ions coming from the disassembly of the [sup 16]O projectile on [sup 27]Al, [sup 58]Ni, and [sup 197]Au targets has been studied at 94 MeV/nucleon. Charged particles have been detected by a multielement array of plastic scintillators covering the angular domain between 3[degree] and 150[degree]. Standard relativistic kinematics has been used to reconstruct the excitation energy of the primary projectilelike nucleus ([ital E][sub PLN][sup *]). Mean values of this quantity are found independent of the target mass and the comparison with existing similar data taken at lower bombarding energies shows a saturation of [ital E][sub PLN][sup *] around 3 MeV/nucleon. An event-by-event analysis has been performed in order to study the distributions of some global variables such as coplanarity, sphericity, and relative angle, helpful in the understanding of the topological characteristics of the process and in the evaluation of its time scale. Experimental data have also been compared with the results of Monte Carlo simulations based on different reaction mechanisms and it is possible to conclude that sequential emission of the fragments is preferred.

  14. The ({sup 18}O, {sup 16}O) reaction as a probe for nuclear spectroscopy

    SciTech Connect

    Cappuzzello, F.; Bondì, M.; Nicolosi, D.; Tropea, S.; Agodi, A.; Carbone, D.; Cavallaro, M.; Cunsolo, A.; Borello-Lewin, T.; Rodrigues, M. R. D.; De Napoli, M.; Linares, R.

    2014-11-11

    The response of nuclei to the ({sup 18}O, {sup 16}O) two-neutron transfer reaction at 84 MeV incident energy has been systematically studied at the Catania INFN-LNS laboratory. The experiments were performed using several solid targets from light ({sup 9}Be, {sup 11}B, {sup 12,13}C, {sup 16}O, {sup 28}Si) to heavy ones ({sup 58,64}Ni, {sup 120}Sn, {sup 208}Pb). The {sup 16}O ejectiles were detected at forward angles by the MAGNEX magnetic spectrometer. Exploiting the large momentum acceptance (−10%, +14%) and solid angle (50 msr) of the spectrometer, energy spectra were obtained with a relevant yield up to about 20 MeV excitation energy. The application of the powerful trajectory reconstruction technique did allow to get energy spectra with energy resolution of about 150 keV and angular distributions with angular resolution better than 0.3°. A common feature observed with light nuclei is the appearance of unknown resonant structures at high excitation energy. The strong population of these latter together with the measured width can reveal the excitation of a collective mode connected with the transfer of a pair.

  15. Feasibility study of the 13C(α, n)16O reaction at LUNA

    NASA Astrophysics Data System (ADS)

    Kochanek, I.; Boeltzig, A.; Ciani, G. F.

    2017-03-01

    The 13C(α, n)16O reaction determines the dominant neutron source of the sprocess in thermally pulsing, low-mass, asymptotic giant branch (TP-AGB) stars. The temperature during the s-process in the 13C pocket of 90×106 K corresponds to a Gamow window of 140-230 keV. Since this energy is far below the Coulomb barrier, the cross section of this reaction is extremely small and its rate can only be extrapolated from the measurements at higher energies. At present, the cross section at Gamow peak is uncertain by almost one order of magnitude. An experimental campaign aimed at measuring low energy cross section in 13C(α n)16O is scheduled at the underground LUNA-400 accelerator in Gran Sasso Laboratory, Italy. The unique underground location of this facility offers significant improvement in sensitivity compared with previous investigations. It will allow to establish the interference pattern of the resonances and the absolute scale of this reaction.

  16. A New Decay Path in the {sup 12}C+{sup 16}O Radiative Capture Reaction

    SciTech Connect

    Courtin, S.; Lebhertz, D.; Haas, F.; Beck, C.; Michalon, A.; Salsac, M.-D.; Jenkins, D. G.; Marley, P.; Lister, C. J.

    2009-03-04

    The {sup 12}C({sup 16}O,{gamma}){sup 28}Si radiative capture reaction has been studied at energies close to the Coulomb barrier at Triumf (Vancouver) using the Dragon spectrometer and its associated BGO array. It has been observed that the {gamma} decay flux proceeds mainly via states around 10-11 MeV and via the direct feeding of the {sup 28}Si 3{sub 1}{sup -}(6879 keV) and 4{sub 2}{sup +}(6888 keV) deformed states. A discussion is presented about this selective feeding as well as perspectives for the use of novel detection systems for the study of light heavy-ion radiative capture reactions.

  17. Dynamics of the 16O(e, e'p) reaction at high missing energies.

    PubMed

    Liyanage, N; Anderson, B D; Aniol, K A; Auerbach, L; Baker, F T; Berthot, J; Bertozzi, W; Bertin, P Y; Bimbot, L; Boeglin, W U; Brash, E J; Breton, V; Breuer, H; Burtin, E; Calarco, J R; Cardman, L; Cates, G D; Cavata, C; Chang, C C; Chen, J P; Cisbani, E; Dale, D S; De Leo, R; Deur, A; Diederich, B; Djawotho, P; Domingo, J; Doyle, B; Ducret, J E; Epstein, M B; Ewell, L A; Finn, J M; Fissum, K G; Fonvieille, H; Frois, B; Frullani, S; Gao, J; Garibaldi, F; Gasparian, A; Gilad, S; Gilman, R; Glamazdin, A; Glashausser, C; Gomez, J; Gorbenko, V; Gorringe, T; Hersman, F W; Holmes, R; Holtrop, M; d'Hose, N; Howell, C; Huber, G M; Hyde-Wright, C E; Iodice, M; de Jager, C W; Jaminion, S; Jones, M K; Joo, K; Jutier, C; Kahl, W; Kato, S; Kelly, J J; Kerhoas, S; Khandaker, M; Khayat, M; Kino, K; Korsch, W; Kramer, L; Kumar, K S; Kumbartzki, G; Laveissière, G; Leone, A; LeRose, J J; Levchuk, L; Liang, M; Lindgren, R A; Lolos, G J; Lourie, R W; Madey, R; Maeda, K; Malov, S; Manley, D M; Margaziotis, D J; Markowitz, P; Martino, J; McCarthy, J S; McCormick, K; McIntyre, J; van der Meer, R L; Meziani, Z E; Michaels, R; Mougey, J; Nanda, S; Neyret, D; Offermann, E A; Papandreou, Z; Perdrisat, C F; Perrino, R; Petratos, G G; Platchkov, S; Pomatsalyuk, R; Prout, D L; Punjabi, V A; Pussieux, T; Quéméner, G; Ransome, R D; Ravel, O; Roblin, Y; Roche, R; Rowntree, D; Rutledge, G A; Rutt, P M; Saha, A; Saito, T; Sarty, A J; Serdarevic-Offermann, A; Smith, T P; Soldi, A; Sorokin, P; Souder, P; Suleiman, R; Templon, J A; Terasawa, T; Todor, L; Tsubota, H; Ueno, H; Ulmer, P E; Urciuoli, G M; Vernin, P; van Verst, S; Vlahovic, B; Voskanyan, H; Watson, J W; Weinstein, L B; Wijesooriya, K; Wilson, R; Wojtsekhowski, B; Zainea, D G; Zeps, V; Zhao, J; Zhou, Z L

    2001-06-18

    We measured the cross section and response functions for the quasielastic 16O(e,e'p) reaction for missing energies 25< or =E(m)< or =120 MeV at missing momenta P(m)< or =340 MeV/c. For 25reaction is dominated by a single 1s(1/2) proton knockout. At larger P(m), the single-particle aspects are increasingly masked by more complicated processes. Calculations which include pion exchange currents, isobar currents, and short-range correlations account for the shape and the transversity, but for only half of the magnitude of the measured cross section.

  18. 12C(alpha,gamma)16O: the key reaction in stellar nucleosynthesis.

    PubMed

    Kunz, R; Jaeger, M; Mayer, A; Hammer, J W; Staudt, G; Harissopulos, S; Paradellis, T

    2001-04-09

    The angular distributions of gamma rays from the 12C(alpha,gamma)16O reaction have been measured at 20 energy points in the energy range E(cm) = 0.95 to 2.8 MeV. The sensitivity of the present experiment compared to previous direct investigations was raised by 1-2 orders of magnitude, by using an array of highly efficient ( 100%) Ge detectors shielded actively with BGOs, as well as high beam currents of up to 500 microA that were provided by the Stuttgart Dynamitron accelerator. The S(E1) and S(E2) factors deduced from the gamma angular distributions have been extrapolated to the range of helium burning temperatures applying the R-matrix method, which yielded S(300)(E1) = (76+/-20) keV b and S(300)(E2) = (85+/-30) keV b.

  19. Evidence of complete fusion in the subbarrier {sup 16}O+{sup 238}U reaction

    SciTech Connect

    Nishio, K. Ikezoe, H.; Asai, M.; Tsukada, K.; Mitsuoka, S.; Tsuruta, K.; Satou, K.; Lin, C. J.; Ohsawa, T.

    2006-08-15

    Evaporation residue cross sections in the {sup 16}O+{sup 238}U reaction were measured for the energy range from above-to extreme subbarrier. We used a He-gas-jet system to transport the fusion products, and the {alpha} decay of the evaporation residues was measured by using a rotating wheel system. The measured cross sections for {sup 248,249,250}Fm are reproduced by a statistical model calculation, for which partial cross sections are calculated by a coupled-channel model taking into account the prolate deformation of {sup 238}U. We conclude that complete fusion is the main process in the subbarrier energy region, and quasifission is not an important channel.

  20. Reaction mechanisms in {sup 16}O+{sup 40}Ca at an incident energy of E({sup 16}O) =86 MeV through inclusive measurements of {alpha} and proton spectra

    SciTech Connect

    Basu, Chinmay; Adhikari, S.; Ghosh, S. K.; Roy, S.; Behera, B. R.; Datta, S. K.

    2007-09-15

    The {alpha} and proton spectra from the {sup 16}O+{sup 40}Ca reaction is measured at E({sup 16}O) =86 MeV at several laboratory angles between 54 deg. and 138 deg. Analysis in terms of the statistical model for compound nuclear reactions show that an event-by-event calculation of the evaporation spectra removes discrepancy observed with standard calculations.

  1. Comment on 'Low-energy cross sections in the {sup 12}C({alpha},{gamma}){sup 16}O reaction'

    SciTech Connect

    Descouvemont, P.; Dufour, M.

    2010-02-15

    We show that the E1 and E2 S factors recommended by Katsuma [Phys. Rev. C 78, 034606 (2008)] do not include well-known constraints and that the model is inappropriate for the {sup 12}C({alpha},{gamma}){sup 16}O reaction.

  2. Toward a reassessment of the 19F(p, α0)16O reaction rate at astrophysical temperatures

    NASA Astrophysics Data System (ADS)

    Lombardo, I.; Dell'Aquila, D.; Di Leva, A.; Indelicato, I.; La Cognata, M.; La Commara, M.; Ordine, A.; Rigato, V.; Romoli, M.; Rosato, E.; Spadaccini, G.; Spitaleri, C.; Tumino, A.; Vigilante, M.

    2015-09-01

    The 19F(p, α0)16O reaction at low energies plays an important role in fundamental physics. In particular in nuclear astrophysics it represents, together with the 19F(p, γ)20Ne reaction, the crossing point between the CNO and the NeNa cycles in stars. Further, in hydrogen-rich stellar environments, it is the most important fluorine destruction channel. In this paper we report new measurements on the 19F(p, α0)16O reaction at deeply sub-Coulomb energies (0.2-0.6 MeV), a region where, despite the key role of this reaction, very few and old data are reported. The deduced astrophysical S-factor is ≈ 1.5- 2 times larger than currently adopted extrapolations with possibly important astrophysical consequences.

  3. Actinides produced by /sup 12/C + /sup 242/Pu and /sup 16/O + /sup 238/U reactions

    SciTech Connect

    Shinohara, N.; Usuda, S.; Ichikawa, S.; Suzuki, T.; Magara, M.; Okashita, H.; Yoshikawa, H.; Horiguchi, T.; Iwata, Y.; Shibata, S.; and others

    1986-09-01

    The cross sections for /sup 250/Fm, /sup 244-246/Cf, /sup 242-244/Cm, and /sup 242/Am/sup g-italic/ produced by the /sup 12/C+ /sup 242/Pu and the /sup 16/O+ /sup 238/U reactions leading to the same compound nucleus of /sup 254/Fm have been measured by using radiochemical methods. The excitation functions show that the difference between the /sup 12/C+ /sup 242/Pu and the /sup 16/O+ /sup 238/U reactions can be attributed mainly to the Coulomb barriers. Our results were compared with others reported previously for /sup 22/Ne+ /sup 232/Th, /sup 12/C+ /sup 238/U, /sup 12/C+ /sup 240,241/Pu, /sup 13/C+ /sup 241/Pu, /sup 16/O+ /sup 233/U, and /sup 16/O+ /sup 242/Pu reaction systems, and support a mechanism involving transfer of ..cap alpha..-particle clusters (C,Be,He) from projectile to target for the production of Cf and Cm isotopes.

  4. Rate coefficients for the OH + pinonaldehyde (C10H16O2) reaction between 297 and 374 K.

    PubMed

    Davis, Maxine E; Talukdar, Ranajit K; Notte, Gregory; Ellison, G Barney; Burkholder, James B

    2007-06-01

    The rate coefficientforthe reaction of OH with pinonaldehyde (C10H16O2, 3-acetyl-2,2-dimethyl-cyclobutyl-ethanal), a product of the atmospheric oxidation of alpha-pinene, was measured under pseudo-first-order conditions in OH at temperatures between 297 and 374 K at 55 and 96 Torr (He). Laser induced fluorescence (LIF) was used to monitor OH in the presence of pinonaldehyde following its production by 248 nm pulsed laser photolysis of H2O2. The reaction exhibits a negative temperature dependence with an Arrhenius expression of k1(T) = (4.5 +/- 1.3) x 10(-12) exp((600 +/- 100)/ 7) cm3 molecule(-1) s(-1); k1(297 K) = (3.46 +/- 0.4) x 10(-11) cm3 molecule(-1) s(-1). There was no observed dependence of the rate coefficient on pressure. Our results are compared with previous relative rate determinations of k1 near 297 K and the discrepancies are discussed. The state of knowledge for the atmospheric processing of pinonaldehyde is reviewed, and its role as a marker for alpha-pinene (monoterpene) chemistry in the atmosphere is discussed.

  5. Quantitative analysis of two-neutron correlations in the 12C(18O,16O)14C reaction

    NASA Astrophysics Data System (ADS)

    Cavallaro, M.; Cappuzzello, F.; Bondì, M.; Carbone, D.; Garcia, V. N.; Gargano, A.; Lenzi, S. M.; Lubian, J.; Agodi, C.; Azaiez, F.; De Napoli, M.; Foti, A.; Franchoo, S.; Linares, R.; Nicolosi, D.; Niikura, M.; Scarpaci, J. A.; Tropea, S.

    2013-11-01

    The 12C(18O,16O)14C and 12,13C(18O,17O)13,14C reactions are studied at 84 MeV. Mass distributions and energy spectra of the ejectiles are measured, indicating the selectivity of these reactions to populate two- and one-neutron configurations in the states of the residual nucleus, respectively. The measured absolute cross-section angular distributions are analyzed by exact finite range coupled reaction channel calculations based on a parameter free double-folding optical potential. The form factors for the (18O,16O) reaction are extracted within an extreme cluster and independent particles scheme with shell-model-derived coupling strengths. The results show that the measured cross sections are accurately described for the first time without the need for any arbitrary scaling factor. The (18O,16O) reaction is thus found to be a powerful tool for quantitative spectroscopic studies of pair configurations in nuclear states.

  6. Direct total cross section measurement of the 16O(α,γ)20Ne reaction at Ec.m.=2.26 MeV

    NASA Astrophysics Data System (ADS)

    Hager, U.; Brown, J. R.; Buchmann, L.; Carmona-Gallardo, M.; Erikson, L.; Fallis, J.; Greife, U.; Hutcheon, D.; Ottewell, D.; Ruiz, C.; Sjue, S.; Vockenhuber, C.

    2011-08-01

    In stellar helium burning, 16O represents the endpoint of the helium-burning sequence due to the low rate of 16O(α,γ)20Ne. We present a new direct measurement of the total capture reaction rate of 16O(α,γ)20Ne at Ec.m.=2.26MeV employing the DRAGON recoil separator. For the first time, the total S factor and its contributing direct capture transitions could be determined in one experiment.

  7. Direct measurement of the 4He (12C, 16O) γ reaction cross section near stellar energies

    NASA Astrophysics Data System (ADS)

    Sagara, Kenshi

    2014-09-01

    The 12C+4He-->16O + γ reaction is one of the key reactions in stellar He-burning, but its total cross section at stellar energy (Ecm = 0.3 MeV) has not been measured yet, in spite of many experiments made in the world for about a half century. At Kyushu University Tandem accelerator Laboratory (KUTL), we have been making direct measurement of the 4He (12C, 16O) γ total cross section below Ecm = 2.4 MeV for about 20 years. We have measured the total cross section at Ecm = 2.4, 1.5 and 1.2 MeV. Now we are preparing to measure the cross section at 1.0 MeV. The direct measurement was made from Ecm = 5 MeV down to 1.9 MeV at Ruhr University, Bochum. We use a pulsed 12C beam and a windowless 4He target, and detect all the 16O recoils in a charge state. A usually continuum 12C beam from our tandem accelerator is pulsed by a pre-buncher, a main buncher, and a beam chopper. Our tandem accelerator was designed to be used at the acceleration voltage of 6-10 MV. For the 4He (12C, 16O) γ experiment we need to use it at 1.3-1.8 MV where beam transmission is very low, then we have invented an acceleration-deceleration method for the tandem accelerator. We have developed a blow-in windowless He target based on an original idea. To separate 16O recoils from the 12C beam, we developed a recoil-mass separator. To reject 12C backgrounds, we developed a long-time chopper, and an ionization chamber. Now, we are preparing to measure time-of-flight of 16O recoils and 12C backgrounds. Many original instruments and the experimental results will be presented. Finally we discuss what are necessary for future direct measurement of the 4He (12C, 16O) γ total cross section below 1.0 MeV, down to 0.7 MeV. A dynamitron accelerator and hard-working researchers may be inevitable. The 12C+4He-->16O + γ reaction is one of the key reactions in stellar He-burning, but its total cross section at stellar energy (Ecm = 0.3 MeV) has not been measured yet, in spite of many experiments made in the world

  8. Low-energy cross sections in the {sup 12}C({alpha},{gamma}){sup 16}O reaction

    SciTech Connect

    Katsuma, M.

    2008-09-15

    The low-energy {sup 12}C({alpha},{gamma}){sup 16}O reaction is analyzed with the potential model. The potentials are chosen from the deep potential describing the {alpha}-particle nuclear rainbow phenomena at high energies. Below E{sub c.m.}=1 MeV, the cross section is found to be dominated by the E2 transition to the ground state of {sup 16}O. No enhancement of the E1 component at low energies is predicted. The extrapolated astrophysical S-factors at E{sub c.m.}=0.3 MeV are S{sub E2}=150 keV b and S{sub E1}=3 keV b.

  9. {sup 16}O resonances near 4α threshold through {sup 12}C({sup 6}Li,d) reaction

    SciTech Connect

    Rodrigues, M. R. D.; Borello-Lewin, T.; Miyake, H.; Horodynski-Matsushigue, L. B.; Duarte, J. L. M.; Rodrigues, C. L.; Faria, P. Neto de; Cunsolo, A.; Cappuzzello, F.; Foti, A.; Agodi, C.; Cavallaro, M.; Napoli, M. di; Ukita, G. M.

    2014-11-11

    Several narrow alpha resonant {sup 16}O states were detected through the {sup 12}C({sup 6}Li,d) reaction, in the range of 13.5 to 17.5 MeV of excitation energy. The reaction was measured at a bombarding energy of 25.5 MeV employing the São Paulo Pelletron-Enge-Spectrograph facility and the nuclear emulsion technique. Experimental angular distributions associated with natural parity quasi-bound states around the 4α threshold are presented and compared to DWBA predictions. The upper limit for the resonance widths obtained is near the energy resolution (15 keV)

  10. Neutral pion production in the [sup 16]O+[sup 27]Al reaction at 94 MeV/nucleon

    SciTech Connect

    Badala, A.; Barbera, R.; Palmeri, A.; Pappalardo, G.S.; Riggi, F.; Russo, A.C.; Agodi, C.; Alba, R.; Bellia, G.; Coniglione, R.; Del Zoppo, A.; Finocchiaro, P.; Maiolino, C.; Migneco, E.; Piattelli, P.; Russo, G.; Sapienza, P.; Peghaire, A. Dipartimento di Fisica, Universita di Catania, Corso Italia 57, I95129 Catania Istituto Nazionale di Fisica Nucleare, Laboratorio Nazionale del Sud, Catania Grand Accelerateur National d'Ions Lourds, Caen )

    1993-01-01

    The production of neutral pions in the reaction [sup 16]O+[sup 27]Al at 94 MeV/nucleon was studied with a multidetector, which includes 180 BaF[sub 2] modules. Kinetic energy spectra for several laboratory angles were measured. The total cross section for neutral pion production was deduced. Results were compared with previous findings on charged pions from the same reaction at the same energy and with the prediction of a dynamical model based on the numerical solution of the Boltzmann-Nordheim-Vlasov equation.

  11. Measuring the 16O(α, γ)20Ne Reaction Rate with the Dragon Recoil Separator at Triumf

    NASA Astrophysics Data System (ADS)

    Hager, U.; Greife, U.; Buchmann, L.; Davids, B.; Fallis, J.; Hutcheon, D.; Ottewell, D.; Reeve, S.; Rojas, A.; Ruiz, C.; Sjue, S. K. L.; Erikson, L.; Carmona-Gallardo, M.; Vockenhuber, C.; Brown, J. R.; Irvine, D.

    2013-03-01

    The DRAGON recoil separator facility at TRIUMF measures radiative α and proton capture reactions of astrophysical importance in inverse kinematics. This is done employing radioactive and stable ion beams produced and accelerated using the ISAC (Isotope Separator and ACcelerator) facility in conjunction with the DRAGON windowless gas target. Over the last few years, the DRAGON collaboration has embarked on a programme to measure a variety of reactions considered vital to the understanding of various astrophysical scenarios. An overview of DRAGON's separation, beam suppression, and detection capabilities will be given. In addition, examples of recent reaction cross section measurements will be discussed, such as the 16O(α, γ)20Ne reaction, which plays an important part in the He and Ne burning in massive stars.

  12. Direct measurement of {sup 4}He({sup 12}C, {sup 16}O){gamma} reaction near stellar energy

    SciTech Connect

    Fujita, K.; Sagara, K.; Teranishi, T.; Goto, T.; Iwabuchi, R.; Matsuda, S.; Oba, N.; Taniguchi, M.; Yamaguchi, H.

    2010-08-12

    A cross section measurement with a direct {sup 16}O detection method for the reaction energy from E{sub cm} = 2.4 down to 0.7 MeV is planned at Kyushu University Tandem Laboratory (KUTL). To perform the experiment successfully and to get the quantitative information of the cross section within the 10% error, we have newly developed several instruments in 2009, such as a blow-in type windowless gas target and movable slit system placed in the recoil mass separator. By using the windowless blow-in gas target, a pressure of 24 Torr was achieved. The effective thickness along the beam axis was measured by p+{sup 4}He scattering. Thanks to the movable slits installed in a recoil mass separator and the trajectory analysis, we found effective reduction of background conditions from the {sup 12}C beam.

  13. The CIELO Collaboration: Neutron Reactions on 1H, 16O, 56Fe, 235,238U, and 239Pu

    NASA Astrophysics Data System (ADS)

    Chadwick, M. B.; Dupont, E.; Bauge, E.; Blokhin, A.; Bouland, O.; Brown, D. A.; Capote, R.; Carlson, A.; Danon, Y.; De Saint Jean, C.; Dunn, M.; Fischer, U.; Forrest, R. A.; Frankle, S. C.; Fukahori, T.; Ge, Z.; Grimes, S. M.; Hale, G. M.; Herman, M.; Ignatyuk, A.; Ishikawa, M.; Iwamoto, N.; Iwamoto, O.; Jandel, M.; Jacqmin, R.; Kawano, T.; Kunieda, S.; Kahler, A.; Kiedrowski, B.; Kodeli, I.; Koning, A. J.; Leal, L.; Lee, Y. O.; Lestone, J. P.; Lubitz, C.; MacInnes, M.; McNabb, D.; McKnight, R.; Moxon, M.; Mughabghab, S.; Noguere, G.; Palmiotti, G.; Plompen, A.; Pritychenko, B.; Pronyaev, V.; Rochman, D.; Romain, P.; Roubtsov, D.; Schillebeeckx, P.; Salvatores, M.; Simakov, S.; Soukhovitskiı˜, E. Sh.; Sublet, J. C.; Talou, P.; Thompson, I.; Trkov, A.; Vogt, R.; van der Marck, S.

    2014-04-01

    CIELO (Collaborative International Evaluated Library Organization) provides a new working paradigm to facilitate evaluated nuclear reaction data advances. It brings together experts from across the international nuclear reaction data community to identify and document discrepancies among existing evaluated data libraries, measured data, and model calculation interpretations, and aims to make progress in reconciling these discrepancies to create more accurate ENDF-formatted files. The focus will initially be on a small number of the highest-priority isotopes, namely 1H, 16O, 56Fe, 235,238U, and 239Pu. This paper identifies discrepancies between various evaluations of the highest priority isotopes, and was commissioned by the OECD's Nuclear Energy Agency WPEC (Working Party on International Nuclear Data Evaluation Co-operation) during a meeting held in May 2012. The evaluated data for these materials in the existing nuclear data libraries - ENDF/B-VII.1, JEFF-3.1, JENDL-4.0, CENDL-3.1, ROSFOND, IRDFF 1.0 - are reviewed, discrepancies are identified, and some integral properties are given. The paper summarizes a program of nuclear science and computational work needed to create the new CIELO nuclear data evaluations.

  14. Fission fragment angular distributions in the reactions {sup 16}O+{sup 188}Os and {sup 28}Si+{sup 176}Yb

    SciTech Connect

    Tripathi, R.; Sudarshan, K.; Sharma, S. K.; Reddy, A. V. R.; Pujari, P. K.; Goswami, A.; Ramachandran, K.

    2009-06-15

    Fission fragment angular distributions have been measured in the reactions {sup 16}O+{sup 188}Os and {sup 28}Si+{sup 176}Yb to investigate the contribution from noncompound nucleus fission. Parameters for statistical model calculations were fixed using fission cross section data in the {sup 16}O+{sup 188}Os reaction. Experimental anisotropies were in reasonable agreement with those calculated using the statistical saddle point model for both reactions. The present results are also consistent with those of mass distribution studies in the fission of {sup 202}Po, formed in the reactions with varying entrance channel mass asymmetry. However, the present studies do not show a large fusion hindrance as reported in the pre-actinide region based on the measurement of evaporation residue cross section.

  15. The 13C(α,n)16O reaction: A background source for underground astrophysics measurements and geo-neutrino measurements

    NASA Astrophysics Data System (ADS)

    Febbraro, Michael; Toomey, Rebecca; Deboer, James; Pain, Steven; Peters, William; Smith, Karl; Becchetti, Fred; Wiescher, Michael

    2016-09-01

    In this study, we present results for a neutron spectroscopic study of the 13C(α,n)16O reaction between E α = 3 . 5 and 7.5 MeV performed at the University of Notre Dame Nuclear Science Laboratory. The neutron spectroscopy measurement was performed with deuterated liquid scintillator detectors capable of extracting neutron energy spectra without neutron time-of-flight measurement using spectral unfolding technique. This permitted extraction of the ground state contribution as well as excited state contributions to the total reaction cross section. The usefulness of this technique for the measurement of beam-induced neutron background sources in deep underground nuclear astrophysics measurements will be shown. Results showing the contributions of excited state components to the total cross section will be given and their implication to geo-neutrino measurements will be discussed. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, NSF Grant PHY0969456, PHY1401343, and Defense Nuclear Nonproliferation R&D (NA-22).

  16. Reaction rate of the 13C(α,n)16O neutron source using the ANC of the -3 keV resonance measured with the THM

    NASA Astrophysics Data System (ADS)

    La Cognata, M.; Spitaleri, C.; Trippella, O.; Kiss, G. G.; Rogachev, G. V.; Mukhamedzhanov, A. M.; Avila, M.; Guardo, G. L.; Koshchiy, E.; Kuchera, A.; Lamia, L.; Puglia, S. M. R.; Romano, S.; Santiago, D.; Spartà, R.

    2016-01-01

    The s-process is responsible of the synthesis of most of the nuclei in the mass range 90 ≤ A ≤ 208. It consists in a series of neutron capture reactions on seed nuclei followed by β-decays, since the neutron accretion rate is slower than the β-decay rate. Such small neutron flux is supplied by the 13C(α,n)16O reaction. It is active inside the helium-burning shell of asymptotic giant branch stars, at temperatures < 108 K, corresponding to an energy interval of 140-230 keV. In this region, the astrophysical S (E)-factor is dominated by the -3 keV sub-threshold resonance due to the 6.356 MeV level in 17O. In this work, we have applied the Trojan Horse Method (THM) to the 13C(6Li,n16O)d quasi-free reaction to extract the 6.356 MeV level resonance parameters, in particular the asymptotic normalization coefficient . A preliminary analysis of a partial data set has lead to , slightly larger than the values in the literature. However, the deduced 13C(α, n)16O reaction rate is in agreement with most results in the literature at ˜ 108 K, with enhanced accuracy thanks to our innovative approach merging together ANC and THM.

  17. The 13C(α,n)16O reaction as a neutron source for the s-process in AGB low-mass stars

    NASA Astrophysics Data System (ADS)

    Trippella, O.; Busso, M.; La Cognata, M.; Spitaleri, C.; Kiss, G. G.; Rogachev, G. V.; Mukhamedzhanov, A. M.; Avila, M.; Guardo, G. L.; Koshchiy, E.; Kuchera, A.; Lamia, L.; Maiorca, E.; Palmerini, S.; Puglia, S. M. R.; Romano, S.; Santiago, D.; Spartà, R.

    2014-05-01

    The 13C(α,n)16O reaction is considered to be the most important neutron source for producing the main component of the s-process in low mass stars. In this paper we focus our attention on two of the main open problems concerning its operation as a driver for the slow neutron captures. Recently, a new measurement of the 13C(α,n)16O reaction rate was performed via the Trojan Horse Method greatly increasing the accuracy. Contemporarily, on the modelling side, magnetic mechanisms were suggested to justify the production of the 13C pocket, thus putting the s-process in stars on safe physical ground. These inputs allow us to reproduce satisfactorily the solar distribution of elements.

  18. Quantum dynamics of {sup 16}O + {sup 36}O{sub 2} and {sup 18}O + {sup 32}O{sub 2} exchange reactions

    SciTech Connect

    Rajagopala Rao, T.; Mahapatra, S.; Guillon, G.; Honvault, P.

    2015-05-07

    We present quantum dynamical investigations of {sup 16}O + {sup 36}O{sub 2} and {sup 18}O + {sup 32}O{sub 2} exchange reactions using a time-independent quantum mechanical method and an accurate global potential energy surface of ozone [Dawes et al., J. Chem. Phys. 135, 081102 (2011)]. Initial state-selected integral cross sections, rate constants, and Boltzmann averaged thermal rate constants are obtained and compared with earlier experimental and theoretical results. The computed thermal rate constants for the oxygen exchange reactions exhibit a negative temperature dependence, as found experimentally. They are in better agreement with the experiments than the previous studies on the same reactions.

  19. New decay branches of the radiative capture reaction {sup 12}C({sup 16}O,{gamma}){sup 28}Si

    SciTech Connect

    Lebhertz, D.; Courtin, S.; Haas, F.; Salsac, M.-D.; Beck, C.; Michalon, A.; Rousseau, M.; Marley, P. L.; Glover, R. G.; Kent, P. E.; Hutcheon, D. A.; Davis, C.; Pearson, J. E.

    2009-01-28

    Resonances in the {sup 12}C({sup 16}O,{gamma}){sup 28}Si radiative capture process at energies around the Coulomb barrier have been probed using the very selective 0 deg. Dragon spectrometer at Triumf and its associated BGO {gamma}-array. For the first time the full level scheme involved in this process has been measured and shows previously unobserved {gamma}-decay to doorway states around 11 MeV in {sup 28}Si.

  20. Quantitative Proteomic Analysis of Mouse Embryonic Fibroblasts and Induced Pluripotent Stem Cells Using 16O /18O labeling

    SciTech Connect

    Huang, Xin; Tian, Changhai; Liu, Miao; Wang, Yongxiang; Tolmachev, Aleksey V.; Sharma, Seema; Yu, Fang; Fu, Kai; Zheng, Jialin; Ding, Shi-Jian

    2012-04-06

    Induced pluripotent stem cells (iPSC) hold great promise for regenerative medicine as well as for investigations into the pathogenesis and treatment of various diseases. Understanding of key intracellular signaling pathways and protein targets that control development of iPSC from somatic cells is essential for designing new approaches to improve reprogramming efficiency. Here we report the development and application of an integrated quantitative proteomics platform for investigating differences in protein expressions between mouse embryonic fibroblasts (MEF) and MEF-derived iPSC. This platform consists of 16O/18O labeling, multidimensional peptide separation coupled with tandem mass spectrometry, and data analysis with UNiquant software. Using this platform a total of 2,481 proteins were identified and quantified from the 16O/18O-labeled MEF-iPSC proteome mixtures with a false discovery rate of 0.01. Among them, 218 proteins were significantly upregulated, while 247 proteins were significantly downregulated in iPSC compared to MEF. Many nuclear proteins, including Hdac1, Dnmt1, Pcna, Ccnd1, Smarcc1, and subunits in DNA replication and RNA polymerase II complex were found to be enhanced in iPSC. Protein network analysis revealed that Pcna functions as a hub orchestrating complicated mechanisms including DNA replication, epigenetic inheritance (Dnmt1) and chromatin remodeling (Smarcc1) to reprogram MEF and maintain stemness of iPSC.

  1. Determination of astrophysical thermonuclear rates with a bubble chamber: The {sup 12}C(αγ){sup 16}O reaction case

    SciTech Connect

    DiGiovine, B.; Henderson, D.; Holt, R. J.; Rehm, K. E.; Grames, J.; Meekins, D.; Poelker, M.; Suleiman, R.; Robinson, A.; Ugalde, C.; Sonnenschein, A.

    2013-11-07

    The {sup 12}C(αγ){sup 16}O reaction rate is considered one of the most important unknown parameters in the physics of structure and evolution of massive stars. While extensive experimental campaigns have been performed trying to improve the quality of the measurements, the rate still holds very large uncertainties. Here we discuss a new experimantal scheme to measure the cross section of this reaction with a bubble chamber and a bremsstrahlung beam. The main advantage of the technique is a gain in the luminosity of several orders of magnitude when compared to other ongoing experiments.

  2. NEW DETERMINATION OF THE {sup 13}C({alpha}, n){sup 16}O REACTION RATE AND ITS INFLUENCE ON THE s-PROCESS NUCLEOSYNTHESIS IN AGB STARS

    SciTech Connect

    Guo, B.; Li, Z. H.; Li, Y. J.; Su, J.; Yan, S. Q.; Bai, X. X.; Chen, Y. S.; Fan, Q. W.; Jin, S. J.; Li, E. T.; Li, Z. C.; Lian, G.; Liu, J. C.; Liu, X.; Shu, N. C.; Lugaro, M.; Buntain, J.; Pang, D. Y.; Karakas, A. I.; Shi, J. R. E-mail: guobing@ciae.ac.cn; and others

    2012-09-10

    We present a new measurement of the {alpha}-spectroscopic factor (S{sub {alpha}}) and the asymptotic normalization coefficient for the 6.356 MeV 1/2{sup +} subthreshold state of {sup 17}O through the {sup 13}C({sup 11}B, {sup 7}Li){sup 17}O transfer reaction and we determine the {alpha}-width of this state. This is believed to have a strong effect on the rate of the {sup 13}C({alpha}, n){sup 16}O reaction, the main neutron source for slow neutron captures (the s-process) in asymptotic giant branch (AGB) stars. Based on the new width we derive the astrophysical S-factor and the stellar rate of the {sup 13}C({alpha}, n){sup 16}O reaction. At a temperature of 100 MK, our rate is roughly two times larger than that by Caughlan and Fowler and two times smaller than that recommended by the NACRE compilation. We use the new rate and different rates available in the literature as input in simulations of AGB stars to study their influence on the abundances of selected s-process elements and isotopic ratios. There are no changes in the final results using the different rates for the {sup 13}C({alpha}, n){sup 16}O reaction when the {sup 13}C burns completely in radiative conditions. When the {sup 13}C burns in convective conditions, as in stars of initial mass lower than {approx}2 M{sub Sun} and in post-AGB stars, some changes are to be expected, e.g., of up to 25% for Pb in our models. These variations will have to be carefully analyzed when more accurate stellar mixing models and more precise observational constraints are available.

  3. Multipolarity analysis for {sup 14}C high-energy resonance populated by ({sup 18}O,{sup 16}O) two-neutron transfer reaction

    SciTech Connect

    Carbone, D. Cavallaro, M.; Bondì, M.; Agodi, C.; Cunsolo, A.; Cappuzzello, F.; Azaiez, F.; Franchoo, S.; Khan, E.; Bonaccorso, A.; Fortunato, L.; Foti, A.; Linares, R.; Lubian, J.; Scarpaci, J. A.; Vitturi, A.

    2015-10-15

    The {sup 12}C({sup 18}O,{sup 16}O){sup 14}C reaction at 84 MeV incident energy has been explored up to high excitation energy of the residual nucleus thanks to the use of the MAGNEX spectrometer to detect the ejectiles. In the region above the two-neutron separation energy, a resonance has been observed at 16.9 MeV. A multipolarity analysis of the cross section angular distribution indicates an L = 0 character for such a transition.

  4. 8Be+8Be and 12C+α breakup states in 16O populated via the 13C(4He,4 α )n reaction

    NASA Astrophysics Data System (ADS)

    Curtis, N.; Almaraz-Calderon, S.; Aprahamian, A.; Ashwood, N. I.; Barr, M.; Bucher, B.; Copp, P.; Couder, M.; Fang, X.; Freer, M.; Goldring, G.; Jung, F.; Lesher, S. R.; Lu, W.; Malcolm, J. D.; Roberts, A.; Tan, W. P.; Wheldon, C.; Ziman, V. A.

    2016-09-01

    The 13C(4He,4 α )n breakup reaction has been studied at beam energies of 27.0, 27.5, and 28.0 MeV. A comparison with previous measurements of the 12C(4He,8Be)8Be excitation function and 12C(16O,4 α )12C breakup channel suggests the Be8gs+Be8gs decay of 16O is observed from a possible 2+ state at 17.3 ±0.2 MeV, a 4+ state at 18.0 ±0.2 MeV, a 2+ or 4+ state at 19.4 ±0.2 MeV, and a 4+ or 6+ state at 21.0 ±0.2 MeV. The 2+ or 4+ assignment for the (19.4 ±0.2 )-MeV state appears to be supported by the relative cross sections expected for resonant and sequential breakup reactions.

  5. Probing the 12C - 12C and 12C - 16O Molecular States by Radiative Capture Reactions:. Present Status and Future

    NASA Astrophysics Data System (ADS)

    Lebhertz, D.; Courtin, S.; Haas, F.; Jenkins, D. G.; Ciemala, M.; Goasduff, A.; Hutcheon, D. A.; Labiche, M.; Michalon, A.; Roberts, O.; Salsac, M.-D.; Stezowski, O.

    Complete γ-decay in the 12C(12C,γ)24Mg and 12C(16O,γ)28Si reactions has been measured at energies close to the Coulomb Barrier using the DRAGON spectrometer and its associated BGO γ-array at the TRIUMF facility. The experimental data show an important feeding of doorway states around 10-11 MeV in both reactions. Comparisons with simulations allow to extract the full capture cross section and the main spin involved in the process. Different models are confronted to the results : completely statistical, semi-statistical with an unique entrance spin and cluster. The resolution of the BGO enables to eliminate a fully statistical scenario but is not enough to disentangle the two remaining scenarii. It is shown that the future PARIS array composed of the recently developed LaBr3 scintillators will have capabilities to distinguish between these two scenarii.

  6. Study of 16O(12C,α20Ne)α for the investigation of carbon-carbon fusion reaction via the Trojan Horse Method

    NASA Astrophysics Data System (ADS)

    Rapisarda, G. G.; Spitaleri, C.; Bordeanu, C.; Hons, Z.; Kiss, G. G.; La Cognata, M.; Mrazek, J.; Nita, C.; Pantelica, D.; Petrascu, H.; Pizzone, R. G.; Romano, S.; Szücs, T.; Trache, L.; Tumino, A.; Velisa, G.

    2016-04-01

    Carbon-carbon fusion reaction represents a nuclear process of great interest in astrophysics, since the carbon burning is connected with the third phase of massive stars (M > 8 M⊙) evolution. In spite of several experimental works, carbon-carbon cross section has been measured at energy still above the Gamow window moreover data at low energy present big uncertainty. In this paper we report the results about the study of the 16O(12C,α 20Ne)α reaction as a possible three-body process to investigate 12C(12C,α)20Ne at astrophysical energy via Trojan Horse Method (THM). This study represents the first step of a program of experiments aimed to measure the 12C+12C cross section at astrophysical energy using the THM.

  7. Updated THM Astrophysical Factor of the 19F(p, α)16O Reaction and Influence of New Direct Data at Astrophysical Energies

    NASA Astrophysics Data System (ADS)

    La Cognata, M.; Palmerini, S.; Spitaleri, C.; Indelicato, I.; Mukhamedzhanov, A. M.; Lombardo, I.; Trippella, O.

    2015-06-01

    Fluorine nucleosynthesis represents one of the most intriguing open questions in nuclear astrophysics. It has triggered new measurements which may modify the presently accepted paradigm of fluorine production and establish fluorine as an accurate probe of the inner layers of asymptotic giant branch (AGB) stars. Both direct and indirect measurements have attempted to improve the recommended extrapolation to astrophysical energies, showing no resonances. In this work, we will demonstrate that the interplay between direct and indirect techniques represents the most suitable approach to attain the required accuracy for the astrophysical factor at low energies, {{E}c.m.}≲ 300 keV, which is of interest for fluorine nucleosynthesis in AGB stars. We will use the recently measured direct 19F{{(p,α )}16}O astrophysical factor in the 600 keV≲ {{E}c.m.}≲ 800 keV energy interval to renormalize the existing Trojan Horse Method (THM) data spanning the astrophysical energies, accounting for all identified sources of uncertainty. This has a twofold impact on nuclear astrophysics. It shows the robustness of the THM approach even in the case of direct data of questionable quality, as normalization is extended over a broad range, minimizing systematic effects. Moreover, it allows us to obtain more accurate resonance data at astrophysical energies, thanks to the improved 19F{{(p,α )}16}O direct data. Finally, the present work strongly calls for more accurate direct data at low energies, so that we can obtain a better fitting of the direct reaction mechanism contributing to the 19F{{(p,α )}16}O astrophysical factor. Indeed, this work points out that the major source of uncertainty affecting the low-energy S(E) factor is the estimate of the non-resonant contribution, as the dominant role of the 113 keV resonance is now well established.

  8. The dynamics of the quasielastic 16O(e,e'p) reaction at Q{sup 2} = 0.8 (GeV/c){sup 2}

    SciTech Connect

    Kevin Fissum for the JLAB Hall A Collaboration

    2004-01-01

    The physics program in Hall A at Jefferson Lab commenced in the summer of 1997 with a detailed investigation of the 16O(e,e'p) reaction in quasielastic, constant (q,w) kinematics at Q{sup 2} {approx} 0.8 (GeV/c){sup 2}, q {approx} 1 GeV/c, and w {approx} 445 MeV. Use of a self-calibrating, self-normalizing, thin-film waterfall target enabled a systematically rigorous measurement. Differential cross-section data for proton knockout were obtained for 0 < Emiss < 120 MeV and 0 < pmiss < 350 MeV/c. These results have been used to extract the ALT asymmetry and the RL, RT, RLT, and RL+TT effective response functions. Detailed comparisons of the data with Relativistic Distorted-Wave Impulse Approximation, Relativistic Optical-Model Eikonal Approximation, and Relativistic Multiple-Scattering Glauber Approximation calculations are made. The kinematic consistency of the 1p-shell normalization factors extracted from these data with respect to all available 16O(e,e'p) data is examined. The Q2-dependence of the normalization factors is also discussed.

  9. Astrophysical reaction rate for the neutron-generator reaction 13C(alpha,n)16O in asymptotic giant branch stars.

    PubMed

    Johnson, E D; Rogachev, G V; Mukhamedzhanov, A M; Baby, L T; Brown, S; Cluff, W T; Crisp, A M; Diffenderfer, E; Goldberg, V Z; Green, B W; Hinners, T; Hoffman, C R; Kemper, K W; Momotyuk, O; Peplowski, P; Pipidis, A; Reynolds, R; Roeder, B T

    2006-11-10

    The reaction 13C(alpha,n) is considered to be the main source of neutrons for the s process in asymptotic giant branch stars. At low energies, the cross section is dominated by the 1/2+ 6.356 MeV subthreshold resonance in (17)O whose contribution at stellar temperatures is uncertain by a factor of 10. In this work, we performed the most precise determination of the low-energy astrophysical S factor using the indirect asymptotic normalization (ANC) technique. The alpha-particle ANC for the subthreshold state has been measured using the sub-Coulomb alpha-transfer reaction ((6)Li,d). Using the determined ANC, we calculated S(0), which turns out to be an order of magnitude smaller than in the nuclear astrophysics compilation of reaction rates.

  10. The possibility of a new resonance of three-body linear chain structure in the reaction 12C+16O at Ec.mapprox-33.5MeV

    NASA Astrophysics Data System (ADS)

    Kong, Xiangjing; P, L. Li; J, J. Kolata; A, Morsad; L, Goetting; R, A. Kryger; S, Dixit; R, Tighe; W, Chune

    1990-05-01

    There is a peak in the excitation function of total cross section of low energy α-particles in the reaction 12C+16O at Ec.m approx33.5MeV. The experimental distribution of α-particle emitted event has been obtained. The result of theoretical calculation roughly agrees with experimental data, gives an orientation where three-body resonances can be expected, and the information on internal structure of three-body linear chain molecule.

  11. Indirect study of the {sup 13}C({alpha},n){sup 16}O reaction via the {sup 13}C({sup 7}Li,t){sup 17}O transfer reaction

    SciTech Connect

    Pellegriti, M. G.; Hammache, F.; Roussel, P.; Audouin, L.; Beaumel, D.; Fortier, S.; Vilmay, M.; Descouvemont, P.; Gaudefroy, L.; Kiener, J.; Lefebvre-Schuhl, A.; Tatischeff, V.; Stanoiu, M.

    2008-04-15

    The {sup 13}C({alpha},n){sup 16}O reaction is considered the main neutron source for the s process in low mass asymptotic giant branch (AGB) stars. In the Gamow peak, the cross section sensitively depends on the 1/2{sup +} subthreshold state of {sup 17}O (E{sub x}=6.356 MeV). In this work, we determined the astrophysical S factor through an evaluation of the {alpha} spectroscopic factor and the corresponding asymptotic normalization factor (ANC) of the 6.356 MeV state using the transfer reaction {sup 13}C({sup 7}Li,t){sup 17}O at two different incident energies. Our result confirms that the contribution of the 1/2{sup +} state is dominant at astrophysical energies. Our reaction rate at T=0.09 GK is slightly lower than the value adopted in the Nuclear Astrophysics Compilation of REaction rates (NACRE), but two times larger than the one obtained in a recent ANC measurement.

  12. Measurement of the 13C(α, n)16O reaction at astrophysical energies using the Trojan Horse Method. Focus on the -3 keV sub-threshold resonance

    NASA Astrophysics Data System (ADS)

    La Cognata, M.; Spitaleri, C.; Trippella, O.; Kiss, G. G.; Rogachev, G. V.; Mukhamedzhanov, A. M.; Avila, M.; Guardo, G. L.; Koshchiy, E.; Kuchera, A.; Lamia, L.; Puglia, S. M. R.; Romano, S.; Santiago, D.; Spartà, R.

    2014-03-01

    Most of the nuclei in the mass range 90 ≲ A ≲ 208 are produced through the so-called s-process, namely through a series of neutron capture reactions on seed nuclei followed by β-decays. The 13C(α, n)16O reaction is the neutron source for the main component of the s-process. It is active inside the helium-burning shell of asymptotic giant branch stars, at temperatures ≲ 108 K, corresponding to an energy interval of 140 - 230 keV. In this region, the astrophysical S(E)-factor is dominated by the -3 keV sub-threshold resonance due to the 6.356 MeV level in 17O. Direct measurements could not soundly establish its contribution owing to the cross section suppression at astrophysical energies determined by the Coulomb barrier between interacting nuclei. Indirect measurements and extrapolations yielded inconsistent results, calling for further investigations. The Trojan Horse Method turns out to be very suited for the study of the 13C(α, n)16O reaction as it allows us to access the low as well as the negative energy re- gion, in particular in the case of resonance reactions. We have applied the Trojan HorseMethod to the 13C(6Li, n16O)d quasi-free reaction. By using the modified R-matrix approach, the asymptotic normalization coefficient {( {tilde C{α 13{{C}}}17{{O(1/}{{{2}}{ + }}{{)}}}} )^2} of the 6.356 MeV level has been deduced as well as the n-partial width, allowing to attain an unprecedented accuracy for the 13C(α, n)16O astrophysical factor. A preliminary analysis of a partial data set has lead to {( {tilde C{α 13{{C}}}17{{O(1/}{{{2}}{ + }}{{)}}}} )^2} = 6.7 - 0.6 + 0.9 {{f}}{{{m}} - 1}, slightly larger than the values in the literature, determining a 13C(α, n)16O reaction rate in agreement with the most results in the literature at ˜ 108 K, with enhanced accuracy thanks to this innovative approach.

  13. Simulation of (16)O (n, p) (16)N reaction rate and nitrogen-16 inventory in a high performance light water reactor with one pass core.

    PubMed

    Kebwaro, Jeremiah Monari; Zhao, Yaolin; He, Chaohui

    2014-12-01

    The rate of activation of the isotope (16)O to (16)N in a typical HPLWR one pass concept was calculated using MCNP code. A mathematical model was used to track the inventory of the radioisotope (16)N in a unit mass of coolant traversing the system. The water leaving the moderator channels has the highest activity in the circuit, but due to interaction with fresh coolant at the lower plenum, the activity is downscaled. The calculated core exit activity is higher than values reported in literature for commercial boiling water reactors.

  14. Measurement of the -3 keV resonance in the 13C(α,n)16O reaction and its influence on the synthesis of s-process nuclei

    NASA Astrophysics Data System (ADS)

    La Cognata, M.; Spitaleri, C.; Trippella, O.; Kiss, G. G.; Rogachev, G. V.; Mukhamedzhanov, A. M.; Avila, M.; Guardo, G. L.; Koshchiy, E.; Kuchera, A.; Lamia, L.; Puglia, S. M. R.; Romano, S.; Santiago, D.; Spartà, R.

    2012-11-01

    The 13C(α,n)16O reaction is the neutron source for the main component of the s-process, responsible of the production of most nuclei in the mass range 90 < A < 204. It is active inside the helium-burning shell in asymptotic giant branch stars, at temperatures < 108 K, corresponding to an energy interval where the 13C(α,n)16O is effective of 140 - 230 keV. In this region, the astrophysical S(E)-factor is dominated by the -3 keV sub-threshold resonance due to the 6.356 MeV level in 17O, giving rise to a steep increase of the S-factor. Notwithstanding that it plays a crucial role in astrophysics, no direct measurements exist. Therefore, we have applied the Trojan Horse Method (THM) to the 13C(6Li,n16O)d quasi-free reaction to achieve an experimental estimate of such contribution. For the first time, the ANC for the 6.356 MeV level has been deduced through the THM as well as the n-partial width, allowing to attain an unprecedented accuracy in the 13C(α,n)16O study. Though a larger ANC for the 6.356 MeV level is measured, our experimental S(E) factor agrees with the most recent extrapolation in the literature in the 140 - 230 keV energy interval, the accuracy being greatly enhanced thanks to this innovative approach.

  15. Breakup effects on alpha spectroscopic factors of 16O

    NASA Astrophysics Data System (ADS)

    Adhikari, S.; Basu, C.; Sugathan, P.; Jhinghan, A.; Behera, B. R.; Saneesh, N.; Kaur, G.; Thakur, M.; Mahajan, R.; Dubey, R.; Mitra, A. K.

    2017-01-01

    The triton angular distribution for the 12C(7Li,t)16O* reaction is measured at 20 MeV, populating discrete states of 16O. Continuum discretized coupled reaction channel calculations are used to to extract the alpha spectroscopic properties of 16O states instead of the distorted wave born approximation theory to include the effects of breakup on the transfer process. The alpha reduced width, spectroscopic factors and the asymptotic normalization constant (ANC) of 16O states are extracted. The error in the spectroscopic factor is about 35% and in that of the ANC about 27%.

  16. Dynamics of 16,18O-induced reactions using Ni, Ge and Mo targets

    NASA Astrophysics Data System (ADS)

    Rajni; Kaur, Gurvinder; Sharma, Manoj K.

    2016-11-01

    Dynamical cluster decay model (DCM) based on the collective clusterization approach is employed to explore the dynamics of various even-mass Zr isotopes formed in 16O-induced reactions. In reference to the measured fusion cross-section data, various decay modes contributing towards 86,88,90,92Zr∗ nuclei are investigated. Also, the role of deformations and orientation degree of freedom is analyzed by comparing results with spherical choice of fragmentation. In addition to this, the effect of entrance channel is explored for 92Zr∗ and 76Kr∗ nuclei formed in 16O and 18O-induced reactions. Besides this, the dynamics of relatively heavier mass Sn isotopes is exercised using 16O and 18O projectiles. The DCM calculated decay cross-sections find good agreement with available experimental data.

  17. High resolution study of isovector negative parity states in the {sup 16}O({sup 3}He,t){sup 16}F reaction at 140 MeV/nucleon

    SciTech Connect

    Fujita, H.; Berg, G. P. A.; Fujimura, H.; Fujita, K.; Hara, K.; Hatanaka, K.; Kamiya, J.; Nakanishi, K.; Sakamoto, N.; Sakemi, Y.; Shimizu, Y.; Wakasa, T.; Fujita, Y.; Adachi, T.; Shimbara, Y.; Yoshifuku, M.; Rapaport, J.; Botha, N. T.; Kawabata, T.; Neveling, R.

    2009-02-15

    The isovector transitions from the ground state (g.s.) of {sup 16}O to the negative parity states in {sup 16}F, i.e., the J{sup {pi}}=0{sup -} g.s., the 0.193 MeV, 1{sup -} state, the 0.424 MeV, 2{sup -} state, the 0.721 MeV, 3{sup -} state, and the 4{sup -}''stretched'' state at 6.372 MeV, were studied by using a high resolution {sup 16}O({sup 3}He,t){sup 16}F reaction at 140 MeV/nucleon. With the help of high energy resolution, these states were, for the first time, clearly resolved in a charge exchange reaction at an intermediate energy, which favorably excites spin-flip states. Angular distributions of the reaction cross sections were measured in the laboratory frame from 0 deg. to 14 deg. Parameters of phenomenological effective interactions were derived so as to reproduce these angular distributions in distorted wave Born approximation (DWBA) calculations. The angular distribution of the 0{sup -} state could be reproduced well at {theta}{sub c.m.}<10 deg. The empirical values, however, are larger by a factor of 2-2.5 in the larger angle region, where the contribution of the so-called 'condensed pion field' is expected. The high resolution also enabled the decay widths of these states to be measured.

  18. Measurement of the {sup 13}C(α,n){sup 16}O reaction with the Trojan horse method: Focus on the sub threshold resonance at −3 keV

    SciTech Connect

    La Cognata, M.; Spitaleri, C.; Guardo, G. L.; Puglia, S. M. R.; Romano, S.; Spartà, R.; Trippella, O.; Kiss, G. G.; Rogachev, G. V.; Avila, M.; Koshchiy, E.; Kuchera, A.; Santiago, D.; Mukhamedzhanov, A. M.; Lamia, L.

    2014-05-02

    The {sup 13}C(α,n){sup 16}O reaction is the neutron source of the main component of the s-process. The astrophysical S(E)-factor is dominated by the −3 keV sub-threshold resonance due to the 6.356 MeV level in {sup 17}O. Its contribution is still controversial as extrapolations, e.g., through R-matrix calculations, and indirect techniques, such as the asymptotic normalization coefficient (ANC), yield inconsistent results. Therefore, we have applied the Trojan Horse Method (THM) to the {sup 13}C({sup 6}Li,n{sup 16}O)d reaction to measure its contribution. For the first time, the ANC for the 6.356 MeV level has been deduced through the THM, allowing to attain an unprecedented accuracy. Though a larger ANC for the 6.356 MeV level is measured, our experimental S(E) factor agrees with the most recent extrapolation in the literature in the 140-230 keV energy interval, the accuracy being greatly enhanced thanks to this innovative approach, merging together two well establish indirect techniques, namely, the THM and the ANC.

  19. Investigation of fluorine in SiO2 and on Si surface by the 19F(p,αγ)16O reaction, secondary-ion mass spectrometry, and x-ray photoelectron spectroscopy

    NASA Astrophysics Data System (ADS)

    Yu, Byoung-gon; Arai, Eiichi; Nishioka, Yasushiro; Ohji, Yuzuru; Iwata, Seiichi; Ma, T. P.

    1990-04-01

    A fluorinated thermal SiO2, grown after HF surface treatment without de-ionized water rinse, was estimated to contain ˜3×1013 cm-2 of fluorine by the 19F(p,αγ)16O reaction. Secondary-ion mass spectrometry data indicate that the SiF distribution is peaked at the SiO2/Si interface in the fluorinated oxide. The time-dependent change of the absolute amount of fluorine on the HF-treated silicon surface as a function of storage time in air or in vacuum was also investigated by the 19F(p,αγ)16O reaction. The initial number of fluorine atoms on the HF-treated silicon surface was estimated to be ˜1015 cm-2 before substantial desorption took place. Fluorine atoms desorb from the silicon surface much more rapidly if the sample is stored in air than in vacuum. These results were also supported by the x-ray photoelectron spectroscopy measurement.

  20. Analysis of the 19F(p, α0)16O reaction at low energies and the spectroscopy of 20Ne

    NASA Astrophysics Data System (ADS)

    Lombardo, I.; Dell'Aquila, D.; Campajola, L.; Rosato, E.; Spadaccini, G.; Vigilante, M.

    2013-12-01

    The investigation of the 19F(p, α0) reaction at low bombarding energies allows the study of the spectroscopy of the 20Ne compound nucleus in an energy region where the existence of quartet excitations has been suggested in the literature. Moreover, this reaction plays a major role in the fourth branch of the CNO cycle since it is relevant for the correct description of the hydrogen burning of fluorine in stars. For these reasons, we decided to investigate the 19F(p, α0) reaction in the Ep ≃ 0.6-1 MeV energy range. The analysis of angular distributions and excitation functions allows one to improve the 20Ne spectroscopy in an excitation energy region where some ambiguities concerning Jπ assignments exist in the literature. In particular, the present data suggest a Jπ = 0+ assignment to the Ex = 13.642 MeV resonance. For this state, both partial and reduced widths for the α0 channel have been deduced. The trend of the astrophysical factor has been obtained from the integrated cross section. A comparison of the present results with data reported in the literature is also discussed.

  1. Vibrational excitation induces double reaction.

    PubMed

    Huang, Kai; Leung, Lydie; Lim, Tingbin; Ning, Zhanyu; Polanyi, John C

    2014-12-23

    Electron-induced reaction at metal surfaces is currently the subject of extensive study. Here, we broaden the range of experimentation to a comparison of vibrational excitation with electronic excitation, for reaction of the same molecule at the same clean metal surface. In a previous study of electron-induced reaction by scanning tunneling microscopy (STM), we examined the dynamics of the concurrent breaking of the two C-I bonds of ortho-diiodobenzene physisorbed on Cu(110). The energy of the incident electron was near the electronic excitation threshold of E0=1.0 eV required to induce this single-electron process. STM has been employed in the present work to study the reaction dynamics at the substantially lower incident electron energies of 0.3 eV, well below the electronic excitation threshold. The observed increase in reaction rate with current was found to be fourth-order, indicative of multistep reagent vibrational excitation, in contrast to the first-order rate dependence found earlier for electronic excitation. The change in mode of excitation was accompanied by altered reaction dynamics, evidenced by a different pattern of binding of the chemisorbed products to the copper surface. We have modeled these altered reaction dynamics by exciting normal modes of vibration that distort the C-I bonds of the physisorbed reagent. Using the same ab initio ground potential-energy surface as in the prior work on electronic excitation, but with only vibrational excitation of the physisorbed reagent in the asymmetric stretch mode of C-I bonds, we obtained the observed alteration in reaction dynamics.

  2. Direct measurement of the 16O(α,γ)20Ne reaction at Ec.m.=2.43 MeV and 1.69 MeV

    NASA Astrophysics Data System (ADS)

    Hager, U.; Buchmann, L.; Davids, B.; Fallis, J.; Greife, U.; Hutcheon, D. A.; Irvine, D.; Ottewell, D.; Rojas, A.; Reeve, S.; Ruiz, C.

    2012-11-01

    In stars, 16O represents the endpoint of the helium burning sequence due to the low rate of 16O(α,γ)20Ne. We present a new direct measurement of the total cross section of 16O(α,γ)20Ne at Ec.m.=1.69MeV employing the DRAGON recoil separator. In addition, the branching ratios and strength of the Ec.m.=2.426MeV 3- resonance were determined.

  3. Spallation-induced fission reactions

    NASA Astrophysics Data System (ADS)

    Benlliure, J.; Rodríguez-Sánchez, J. L.

    2017-03-01

    During the last decade spallation-induced fission reactions have received particular attention because of their impact in the design of spallation-neutron sources or radioactive beam facilities, but also in the understanding of the fission process at high excitation energy. In this paper, we review the main progress brought by modern experimental techniques, in particular those based in the inverse kinematic, as well as the achievements in modelling these reactions. We will also address future possibilities for improving the investigation of fission dynamics.

  4. Fusion hindrance and quasi-fission in heavy-ion induced reactions: disentangling the effect of different parameters

    SciTech Connect

    Fioretto, E.; Stefanini, A. M.; Behera, B. R.; Corradi, L.; Gadea, A.; Latina, A.; Trotta, M.; Beghini, S.; Montagnoli, G.; Scarlassara, F.; Chizhov, A. Yu.; Itkis, I. M.; Itkis, M. G.; Kniajeva, G. N.; Kondratiev, N. A.; Kozulin, E. M.; Pokrovsky, I. V.; Sagaidak, R. N.; Voskressensky, V. M.; Courtin, S.

    2006-04-26

    Experimental results on the fusion inhibition effect near the Coulomb barrier due to the onset of the quasi-fission mechanism are presented. The investigation was focused on reactions induced by 48Ca projectiles on different heavy targets and comparing them to reactions induced by light ions such as 12C and 16O leading to the same compound nuclei. Cross sections and angular distributions of evaporation residues and fission fragments have been measured.

  5. Excitation of 0/sup -/ states by /sup 16/O(pp')/sup 16/O inelastic scattering

    SciTech Connect

    Hosono, K.; Fujiwara, M.; Hatanaka, K.; Ikegami, H.; Kondo, M.; Matsuoka, N.; Saito, T.; Matsuki, S.; Ogino, K.; Kato, S.

    1984-08-01

    Differential cross sections and analyzing powers for 0/sup -/ states in /sup 16/O have been measured in inelastic scattering of 65 MeV polarized protons. This is the first observation of both isovector and isoscalar 0/sup +/..-->..0/sup -/ transitions in proton scattering on a particular isotope. Microscopic distorted-wave Born approximations and distorted-wave impulse approximation calculations do not describe very well either experimental cross sections or analyzing powers. It is suggested that more complicated reaction mechanisms and wave functions may be needed to describe these transitions.

  6. 16O+12C resonances within the strong absorption region for Ec.m.>23 MeV

    NASA Astrophysics Data System (ADS)

    Jachcinski, C. M.; Braun-Munzinger, P.; Berkowitz, G. M.; Freifelder, R. H.; Gai, M.; Renner, T. R.; Uhlhorn, C. D.

    1980-07-01

    Excitation functions for 12C(16O, 16O)12C elastic and inelastic scattering have been measured in the energy range 23<=Ec.m.<=32 MeV. Two strong structures at Ec.m.=25.5 and 29.6 MeV are observed in the 12C + 16O(3-,6.13 MeV) exit channel; angular correlation measurements at these energies suggest spin assignments of 15- and 16+, respectively. NUCLEAR REACTIONS 12C(16O, 16O*)12C*; Ec.m.=23-32 MeV, θc.m.(16O)=130°-155° measured σ(E) angular correlations.

  7. Reactions Induced by Platelet Transfusions

    PubMed Central

    Kiefel, Volker

    2008-01-01

    Summary Platelet transfusions play a central role in therapeutic regimens for patients with hematologic/oncologic diseases who develop severe thrombocytopenia either in the course of their disease or following cytostatic therapy. Like other blood components, platelet transfusions have achieved a high degree of safety as far as transmission of viral diseases is concerned. However, transfusion of platelet concentrates is accompanied by a high frequency of febrile and anaphylactoid reactions. In rare cases, recipients of platelet concentrates are threatened by severe reactions as septic complications due to bacterial contamination of platelet concentrates, transfusion-related acute lung injury and severe anaphylactic episodes. PMID:21512624

  8. Laser-induced tissue reactions and dermatology.

    PubMed

    Weber, Rebecca J; Taylor, Brent R; Engelman, Dendy E

    2011-01-01

    Knowledge of laser tissue reactions and tissue properties allows the practitioner to tailor a treatment to an individual patient's need and goals. A laser's power, spot size and pulse duration may be manipulated to yield different tissue reactions. Five tissue reactions, each the result of varying laser pulse durations and energy densities, may be achieved. They are photochemical, photothermal, photoablation, plasma-induced ablation and photomechanical. Of these, photothermal reactions are most utilized in dermatology. When higher powered pulses are applied, tissue often undergoes multiple reactions simultaneously. An understanding of these reactions allows their effects to be predicted. In this chapter, the various reactions are reviewed, and the reactions caused by many of the most commonly used lasers in dermatology are discussed.

  9. Knockout of proton-neutron pairs from 16O with electromagnetic probes

    NASA Astrophysics Data System (ADS)

    Middleton, D. G.; Annand, J. R. M.; Barbieri, C.; Giusti, C.; Grabmayr, P.; Hehl, T.; MacGregor, I. J. D.; Martin, I.; McGeorge, J. C.; Moschini, F.; Pacati, F. D.; Schwamb, M.; Watts, D.

    2010-02-01

    After recent improvements to the Pavia model of two-nucleon knockout from 16O with electromagnetic probes the calculated cross-sections are compared to experimental data from such reactions. Comparison with data from a measurement of the 16O (e,e’ pn) reaction cross-section shows much better agreement between the experimental data and the results of the theoretical model than was previously observed. In a comparison with recent data from a measurement of the 16O ( γ ,pn) reaction cross-section the model over-predicts the measured cross-section at low missing momentum.

  10. Dynamical α -cluster model of 16O

    NASA Astrophysics Data System (ADS)

    Halcrow, C. J.; King, C.; Manton, N. S.

    2017-03-01

    We calculate the low-lying spectrum of the 16O nucleus using an α -cluster model which includes the important tetrahedral and square configurations. Our approach is motivated by the dynamics of α -particle scattering in the Skyrme model. We are able to replicate the large energy splitting that is observed between states of identical spin but opposite parities. We also provide a novel interpretation of the first excited state of 16O and make predictions for the energies of 6- states that have yet to be observed experimentally.

  11. Peculiarities of the 16O(α, α) 16O 3.045 Me V resonance scattering and its application to investigation of oxygen in silicon

    NASA Astrophysics Data System (ADS)

    Soroka, V. I.; Artsimovich, M. V.; Lobach, I. Yu.; Mogilnik, I. F.; Pavlovich, V. N.; Tokarevsky, V. V.; Kudriavtsev, E. M.; Romanjuk, B. N.

    1993-11-01

    The elastic scattering of alpha particles by oxygen in the vicinity of the 3.045 MeV resonance was studied with the aim of its use in nuclear microanalysis. The 16O(α, α) 16O resonance scattering was used to investigate the theoretically predicted effect of resonant laser-induced diffusion of impurities in crystals and to determine the lattice site location of oxygen in silicon using the channelling technique.

  12. Quasielastic knockout of light fragments from {sup 12}C and {sup 16}O nuclei by intermediate-energy pions

    SciTech Connect

    Abramov, B. M.; Borodin, Yu. A.; Bulychjov, S. A.; Dukhovskoy, I. A.; Krutenkova, A. P.; Kulikov, V. V. Martemianov, M. A.; Matsuk, M. A.; Tarasov, V. E.; Turdakina, E. N.; Khanov, A. I.

    2007-07-15

    Quasielastic deuteron and triton knockout from {sup 12}C and {sup 16}O nuclei has been studied infull kinematics using a 0.72-GeV/c pion beam. The momentum distributions of the intranuclear quasideuteron motion, excitation-energy spectra of the residual nuclei, and the effective numbers N{sub d}{sup eff} of quasideuterons are determined. The parameters of the quasideuteron intranuclear motion are in reasonable agreement with the results obtained in other beams. The N{sub d}{sup eff} in the nuclei from {sup 6}Li to {sup 16}O measured in full kinematics are virtually independent of the atomic number in contrast to the analogous values in the inclusive deuteron-knockout reaction induced by protons. The phenomenon of triton knockout from these nuclei is observed, which makes possible estimation of the cross section of backward pion-triton elastic scattering in yet unexplored regions of energy and momentum transfer.

  13. Kinetic isotope effect of the {sup 16}O + {sup 36}O{sub 2} and {sup 18}O + {sup 32}O{sub 2} isotope exchange reactions: Dominant role of reactive resonances revealed by an accurate time-dependent quantum wavepacket study

    SciTech Connect

    Sun, Zhigang Yu, Dequan; Xie, Wenbo; Hou, Jiayi; Dawes, Richard; Guo, Hua

    2015-05-07

    The O + O{sub 2} isotope exchange reactions play an important role in determining the oxygen isotopic composition of a number of trace gases in the atmosphere, and their temperature dependence and kinetic isotope effects (KIEs) provide important constraints on our understanding of the origin and mechanism of these and other unusual oxygen KIEs important in the atmosphere. This work reports a quantum dynamics study of the title reactions on the newly constructed Dawes-Lolur-Li-Jiang-Guo (DLLJG) potential energy surface (PES). The thermal reaction rate coefficients of both the {sup 18}O + {sup 32}O{sub 2} and {sup 16}O + {sup 36}O{sub 2} reactions obtained using the DLLJG PES exhibit a clear negative temperature dependence, in sharp contrast with the positive temperature dependence obtained using the earlier modified Siebert-Schinke-Bittererova (mSSB) PES. In addition, the calculated KIE shows an improved agreement with the experiment. These results strongly support the absence of the “reef” structure in the entrance/exit channels of the DLLJG PES, which is present in the mSSB PES. The quantum dynamics results on both PESs attribute the marked KIE to strong near-threshold reactive resonances, presumably stemming from the mass differences and/or zero point energy difference between the diatomic reactant and product. The accurate characterization of the reactivity for these near-thermoneutral reactions immediately above the reaction threshold is important for correct characterization of the thermal reaction rate coefficients.

  14. Cross sections of proton- and neutron-induced reactions by the Liège intranuclear cascade model

    NASA Astrophysics Data System (ADS)

    Chen, Jian; Dong, Tiekuang; Ren, Zhongzhou

    2016-06-01

    The purpose of the paper is mainly to test the validity of the Liège intranuclear cascade (INCL) model in calculating the cross sections of proton-induced reactions for cosmogenic nuclei using the newly compiled database of proton cross sections. The model calculations of 3He display the rising tendency of cross sections with the increase of energy, in accordance with the experimental data. Meanwhile, the differences between the theoretical results and experimental data of production cross sections (10Be and 26Al) are generally within a factor of 3, meaning that the INCL model works quite well for the proton-induced reactions. Based on the good agreement, we predict the production cross sections of 26Al from reactions n + 27Al, n + 28Si, and n + 40Ca and those of 10Be from reactions n + 16O and n + 28Si. The results also show a good agreement with a posteriori excitation functions.

  15. Systemic immunotoxicity reactions induced by adjuvanted vaccines.

    PubMed

    Batista-Duharte, Alexander; Portuondo, Deivys; Pérez, O; Carlos, Iracilda Zeppone

    2014-05-01

    Vaccine safety is a topic of concern for the treated individual, the family, the health care personnel, and the others involved in vaccination programs as recipients or providers. Adjuvants are necessary components to warrant the efficacy of vaccines, however the overstimulation of the immune system is also associated with adverse effects. Local reactions are the most frequent manifestation of toxicity induced by adjuvanted vaccines and, with the exception of the acute phase response (APR), much less is known about the systemic reactions that follow vaccination. Their low frequency or subclinical expression meant that this matter has been neglected. In this review, various systemic reactions associated with immune stimulation will be addressed, including: APR, hypersensitivity, induction or worsening of autoimmune diseases, modification of hepatic metabolism and vascular leak syndrome (VLS), with an emphasis on the mechanism involved. Finally, the authors analyze the current focus of discussion about vaccine safety and opportunities to improve the design of new adjuvanted vaccines in the future.

  16. Spin distribution in neutron induced preequilibrium reactions

    SciTech Connect

    Dashdorj, D; Kawano, T; Chadwick, M; Devlin, M; Fotiades, N; Nelson, R O; Mitchell, G E; Garrett, P E; Agvaanluvsan, U; Becker, J A; Bernstein, L A; Macri, R; Younes, W

    2005-10-04

    The preequilibrium reaction mechanism makes an important contribution to neutron-induced reactions above E{sub n} {approx} 10 MeV. The preequilibrium process has been studied exclusively via the characteristic high energy neutrons produced at bombarding energies greater than 10 MeV. They are expanding the study of the preequilibrium reaction mechanism through {gamma}-ray spectroscopy. Cross-section measurements were made of prompt {gamma}-ray production as a function of incident neutron energy (E{sub n} = 1 to 250 MeV) on a {sup 48}Ti sample. Energetic neutrons were delivered by the Los Alamos National Laboratory spallation neutron source located at the Los Alamos Neutron Science Center facility. The prompt-reaction {gamma} rays were detected with the large-scale Compton-suppressed Germanium Array for Neutron Induced Excitations (GEANIE). Neutron energies were determined by the time-of-flight technique. The {gamma}-ray excitation functions were converted to partial {gamma}-ray cross sections taking into account the dead-time correction, target thickness, detector efficiency and neutron flux (monitored with an in-line fission chamber). Residual state population was predicted using the GNASH reaction code, enhanced for preequilibrium. The preequilibrium reaction spin distribution was calculated using the quantum mechanical theory of Feshback, Kerman, and Koonin (FKK). The multistep direct part of the FKK theory was calculated for a one-step process. The FKK preequilibrium spin distribution was incorporated into the GNASH calculations and the {gamma}-ray production cross sections were calculated and compared with experimental data. The difference in the partial {gamma}-ray cross sections using spin distributions with and without preequilibrium effects is significant.

  17. Fluid transport in reaction induced fractures

    NASA Astrophysics Data System (ADS)

    Ulven, Ole Ivar; Sun, WaiChing; Malthe-Sørenssen, Anders

    2015-04-01

    The process of fracture formation due to a volume increasing chemical reaction has been studied in a variety of different settings, e.g. weathering of dolerites by Røyne et al. te{royne}, serpentinization and carbonation of peridotite by Rudge et al. te{rudge} and replacement reactions in silica-poor igneous rocks by Jamtveit et al. te{jamtveit}. It is generally assumed that fracture formation will increase the net permeability of the rock, and thus increase the reactant transport rate and subsequently the total rate of material conversion, as summarised by Kelemen et al. te{kelemen}. Ulven et al. te{ulven_1} have shown that for fluid-mediated processes the ratio between chemical reaction rate and fluid transport rate in bulk rock controls the fracture pattern formed, and Ulven et al. te{ulven_2} have shown that instantaneous fluid transport in fractures lead to a significant increase in the total rate of the volume expanding process. However, instantaneous fluid transport in fractures is clearly an overestimate, and achievable fluid transport rates in fractures have apparently not been studied in any detail. Fractures cutting through an entire domain might experience relatively fast advective reactant transport, whereas dead-end fractures will be limited to diffusion of reactants in the fluid, internal fluid mixing in the fracture or capillary flow into newly formed fractures. Understanding the feedback process between fracture formation and permeability changes is essential in assessing industrial scale CO2 sequestration in ultramafic rock, but little is seemingly known about how large the permeability change will be in reaction-induced fracturing. In this work, we study the feedback between fracture formation during volume expansion and fluid transport in different fracture settings. We combine a discrete element model (DEM) describing a volume expanding process and the related fracture formation with different models that describe the fluid transport in the

  18. Measurements and analysis of alpha-induced reactions of importance for nuclear astrophysics

    NASA Astrophysics Data System (ADS)

    de Messieres, Genevieve Escande

    2011-11-01

    Reactions during stellar helium burning are of primary importance for understanding nucleosynthesis. A detailed understanding of the critical reaction chain 4He(2alpha, gamma)12C( alpha, gamma)16O(alpha, gamma) 20Ne is necessary both because it is the primary energy source and because it determines the ratio of 12C to 16O produced, which in turn significantly effects subsequent nucleosynthesis. Also during Helium burning, the reactions 22Ne(alpha, n)25Mg and 22Ne(alpha, gamma )26Mg are crucial in determining the amount of neutrons available for the astrophysical s-process. This thesis presents new experimental results concerning the 16O(alpha, gamma) 20Ne, 22Ne(alpha, n)25Mg, and 22Ne(alpha, gamma)26Mg reaction rates. These results are then applied to the calculation of the associated stellar reaction rates in order to achieve better accuracy.

  19. High-resolution measurement of absolute {alpha}-decay widths in {sup 16}O

    SciTech Connect

    Wheldon, C.; Ashwood, N. I.; Barr, M.; Curtis, N.; Freer, M.; Kokalova, Tz.; Malcolm, J. D.; Spencer, S. J.; Ziman, V. A.; Faestermann, Th.; Kruecken, R.; Wirth, H.-F.; Hertenberger, R.; Lutter, R.; Bergmaier, A.

    2011-06-15

    By using a large-acceptance position-sensitive silicon detector array in coincidence with the high-resolution Munich Q3D spectrograph, unambiguous measurements have been made of the absolute {alpha}-particle decay widths from excited states in {sup 16}O* in the energy range 13.85 to 15.87 MeV. Carbon targets have been bombarded with 42-MeV {sup 6}Li beams to induce {sub 6}{sup 12}C({sub 3}{sup 6}Li, d){sub 8}{sup 16}O* reactions. The deuteron ejectiles were measured in the Q3D and the results gated by {sup 4}He+{sup 12}C breakup products detected in the silicon array, the efficiency of which was modeled using Monte Carlo simulations. By comparing total population and breakup-gated spectra, the following absolute {alpha}-decay widths have been measured with high resolution: {Gamma}{sub {alpha}}0/{Gamma}{sub tot} = 0.87{+-}0.11 (13.980 MeV), 1.04{+-}0.15 (14.302 MeV), 0.92{+-}0.10 (14.399 MeV), 0.59{+-}0.04 (14.815 MeV), 0.88{+-}0.18 (15.785 MeV), and {Gamma}{sub {alpha}}1/{Gamma}{sub tot}=1.14{+-}0.08 (14.660 MeV), 0.46{+-}0.06 (14.815 MeV).

  20. Heavy isotope production by multinucleon transfer reactions with /sup 254/Es. [101 MeV /sup 16/O, 98 MeV /sup 18/O, 127 MeV /sup 22/Ne

    SciTech Connect

    Schaedel, M.; Bruechle, W.; Bruegger, M.; Gaeggeler, H.; Moody, K.J.; Schardt, D.; Suemmerer, K.; Hulet, E.K.; Douran, A.D.; Dougan, R.J.

    1985-01-01

    Fast automated on-line and quasi-on-line radiochemical techniques were applied to search for new isotopes, to measure their decay characteristics, and to study the cross sections of the heaviest, most neutron-rich actinide isotopes in reactions of /sup 16,18/O and /sup 22/Ne projectiles with /sup 254/Es as a target. The measured yields for isotopes up to Lr-260 are three or more orders of magnitude higher than in any other reaction used so far. A comparison with data for similar transfers from /sup 248/Cm targets is made. Transfer cross sections are extrapolated for the production of unknown, neutron-rich isotopes of elements 101 through 105, and the unique potential of /sup 254/Es as a target to make these exoctic nuclei accessible is demonstrated. 18 refs., 2 figs., 1 tab.

  1. Static versus energy-dependent nucleus-nucleus potential for description of sub-barrier fusion dynamics of {}_{8}^{16}O+{}^{112,116,120}\\!\\!\\!\\!\\!\\!{}_{50}Sn reactions

    NASA Astrophysics Data System (ADS)

    Manjeet Singh, Gautam

    2015-11-01

    The static and energy-dependent nucleus-nucleus potentials are simultaneously used along with the Wong formula for exploration of fusion dynamics of {}816O+{}112,116,120{}50Sn reactions. The role of internal structure degrees of freedom of colliding pairs, such as inelastic surface vibrations, are examined within the context of coupled channel calculations performed using the code CCFULL. Theoretical calculations based on the static Woods-Saxon potential along with the one-dimensional Wong formula fail to address the fusion data of {}816O+{}112,116,120{}50Sn reactions. Such discrepancies can be removed if one uses couplings to internal structure degrees of freedom of colliding nuclei. However, the energy-dependent Woods-Saxon potential model (EDWSP model) accurately describes the sub-barrier fusion enhancement of {}816O+{}112,116,120{}50Sn reactions. Therefore, in sub-barrier fusion dynamics, energy dependence in the nucleus-nucleus potential governs barrier modification effects in a closely similar way to that of the coupled channel approach. Supported by Dr. D. S. Kothari Post-Doctoral Fellowship Scheme sponsored by University Grants Commission (UGC), New Delhi, India

  2. Competing reaction channels in IR-laser-induced unimolecular reactions

    SciTech Connect

    Berman, M.R.

    1981-01-01

    The competing reaction channels in the unimolecular decomposition of two molecules, formaldehyde and tetralin were studied. A TEA CO/sub 2/ laser was used as the excitation source in all experiments. The dissociation of D/sub 2/CO was studied by infrared multiphoton dissociation (MPD) and the small-molecule nature of formaldehyde with regard to MPD was explored. The effect of collisions in MPD were probed by the pressure dependence of the MPD yield and ir fluorescence from multiphoton excited D/sub 2/CO. MPD yield shows a near cubic dependence in pure D/sub 2/CO which is reduced to a 1.7 power dependence when 15 torr of NO is added. The peak amplitude of 5 ..mu..m ir fluorescence from D/sub 2/CO is proportional to the square of the D/sub 2/CO pressure in pure D/sub 2/CO or in the presence of 50 torr of Ar. Results are explained in terms of bottlenecks to excitation at the v = 1 level which are overcome by a combination of vibrational energy transfer and rotational relaxation. The radical/molecule branching ratio in D/sub 2/CO MPD was 0.10 +- 0.02 at a fluence of 125 J/cm/sup 2/ at 946.0 cm/sup -1/. The barrier height to molecular dissociation was calculated to be 3.6 +- 2.0 kcal/mole below the radical threshold or 85.0 +- 3.0 kcal/mole above the ground state of D/sub 2/CO. In H/sub 2/CO, this corresponds to 2.5 +- 2.0 kcal/mole below the radical threshold or 83.8 +- 3.0 kcal/mole above the ground state. Comparison with uv data indicate that RRKM theory is an acceptable description of formaldehyde dissociation in the 5 to 10 torr pressure range. The unimolecular decomposition of tetralin was studied by MPD and SiF/sub 4/ - sensitized pyrolysis. Both techniques induce decomposition without the interference of catalytic surfaces. Ethylene loss is identified as the lowest energy reaction channel. Dehydrogenation is found to result from step-wise H atom loss. Isomerization via disproportionation is also identified as a primary reaction channel.

  3. Assessment of experimental d-PIGE γ-ray production cross sections for 12C, 14N and 16O and comparison with absolute thick target yields

    NASA Astrophysics Data System (ADS)

    Csedreki, L.; Halász, Z.; Kiss, Á. Z.

    2016-08-01

    Measured differential cross sections for deuteron induced γ-ray emission from the reactions 12C(d,pγ)13C, (Eγ = 3089 keV), 14N(d,pγ)15N (Eγ = 8310 keV) and 16O(d,pγ)17O (Eγ = 871 keV) available in the literature were assessed. In order to cross check the assessed γ-ray production cross section data, thick target γ-yields calculated from the differential cross sections were compared with available measured thick target yields. Recommended differential cross section data for each reaction were deduced for particle induced γ-ray emission (PIGE) applications.

  4. Theory of photon and electron induced reactions

    SciTech Connect

    Onley, D.S.; Wright, L.E.

    1992-01-01

    During the first year and half of the current grant from the Department of Energy we have made considerable progress on the following aspects of the general investigation of electron and photon induced reactions: (1) photo- and electro-production of mesons; (2) Coulomb distortion effects on (e,e{prime}{gamma}) and (e,e{prime}) and (e,e{prime}p) in the quasi-elastic region, (3) studies involving the relativistic shell model, and (4) quark models. We will report on each of these developments in this paper.

  5. Microwave Spectrum of 12C16O

    NASA Astrophysics Data System (ADS)

    Tashkun, S. A.; Mikhailenko, S. N.

    2010-06-01

    12C16O microwave spectrum of the 0-0,1-1,2-2, and 3-3 bands up to J=50 will be presented. The spectrum was calculated from an experimental dataset of energy levels. Calculated frequencies are given together with 99% confidence intervals. Comparison of the spectrum with microwave data containing in spectroscopic databanks will be discussed. This work was supported by CRDF (USA) Grant RUG1-2954-TO-09 and by RFBR. Grant 09-05-92508. S.A. Tashkun, T.I. Velichko, S.N. Mikhailenko, JQSRT, in press (2010).

  6. Neutrino-induced reactions on nuclei

    NASA Astrophysics Data System (ADS)

    Gallmeister, K.; Mosel, U.; Weil, J.

    2016-09-01

    Background: Long-baseline experiments such as the planned deep underground neutrino experiment (DUNE) require theoretical descriptions of the complete event in a neutrino-nucleus reaction. Since nuclear targets are used this requires a good understanding of neutrino-nucleus interactions. Purpose: Develop a consistent theory and code framework for the description of lepton-nucleus interactions that can be used to describe not only inclusive cross sections, but also the complete final state of the reaction. Methods: The Giessen-Boltzmann-Uehling-Uhlenbeck (GiBUU) implementation of quantum-kinetic transport theory is used, with improvements in its treatment of the nuclear ground state and of 2p2h interactions. For the latter an empirical structure function from electron scattering data is used as a basis. Results: Results for electron-induced inclusive cross sections are given as a necessary check for the overall quality of this approach. The calculated neutrino-induced inclusive double-differential cross sections show good agreement data from neutrino and antineutrino reactions for different neutrino flavors at MiniBooNE and T2K. Inclusive double-differential cross sections for MicroBooNE, NOvA, MINERvA, and LBNF/DUNE are given. Conclusions: Based on the GiBUU model of lepton-nucleus interactions a good theoretical description of inclusive electron-, neutrino-, and antineutrino-nucleus data over a wide range of energies, different neutrino flavors, and different experiments is now possible. Since no tuning is involved this theory and code should be reliable also for new energy regimes and target masses.

  7. Reaction induced fractures in 3D

    NASA Astrophysics Data System (ADS)

    Ulven, Ole Ivar; Malthe-Sørenssen, Anders

    2014-05-01

    The process of fracture formation due to volume changing processes has been studied numerically in a variety of different settings, e.g. fracture initiation in general volume increasing reactions by Ulven et al.[4], weathering of dolerites by Røyne et al.[2], and volume reduction during chemical decomposition prosesses by Malthe-Sørenssen et al.[1]. Common to many previous works is that the simulations were performed in a 2D setting, due to computational limitations. Fractures observed both in field studies and in experiments are in many cases three dimensional. It remains an open question in what cases the simplification to 2D systems is applicable, and when a full 3D simulation is necessary. In this study, we use a newly developed 3D code combining elements from the discrete element model (DEM) with elements from Peridynamics[3]. We study fracture formation in fully three dimensional simulations, and compare them with simulation results from 2D DEM, thus gaining insight in both qualitative and quantitative differences between results from 2D and 3D simulations. References [1] Malthe-Sørenssen, A., Jamtveit, B., and Meakin, P., 'Fracture Patterns Generated by Diffusion Controlled Volume Changing Reactions,' Phys. Rev. Lett. 96, 2006, pp. 245501-1 - 245501-4. [2] Røyne, A., Jamtveit, B., and Malthe-Sørenssen, A., 'Controls on rock weathering rates by reaction-induced hierarchial fracturing,' Earth Planet. Sci. Lett. 275, 2008, pp. 364 - 369. [3] Silling, S. A., 'Reformulation of elasticity theory for discontinuities and long-range forces,' J. Mech. Phys. Solids, 48, Issue 1, 2000, pp. 175 - 209 [4] Ulven, O. I., Storheim, H., Austrheim, H., and Malthe-Sørenssen, A., 'Fracture Initiation During Volume Increasing Reactions in Rocks and Applications for CO2 Sequestration', Earth Planet. Sci. Lett. 389C, 2014, pp. 132 - 142.

  8. Epidemiology of cutaneous drug-induced reactions.

    PubMed

    Naldi, L; Crotti, S

    2014-04-01

    Cutaneous reactions represent in many surveillance systems, the most frequent adverse events attributable to drugs. The spectrum of clinical manifestations is wide and virtually encompasses any known dermatological disease. The introduction of biological agents and so-called targeted therapies has further enlarged the number of reaction patterns especially linked with cytokine release or in balance. The frequency and clinical patterns of cutaneous reactions are influenced by drug use, prevalence of specific conditions (e.g., HIV infection) and pharmacogenetic traits of a population, and they may vary greatly among the different populations around the world. Studies of reaction rates in cohorts of hospitalized patients revealed incidence rates ranging from, 1 out 1000 to 2 out 100 of all hospitalized patients. For drugs such as aminopenicillines and sulfamides the incidence of skin reactions is in the order of 3-5 cases out of 100 exposed people. Although the majority of cutaneous reactions are mild and self-limiting, there are reactions such as Stevens Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and drug reaction with eosinophilia and systemic symptoms (DRESS) which are associated with significant morbidity and mortality. Surveillance systems routed on sound epidemiologic methodology, are needed to raise signals and to assess risks associated with specific reactions and drug exposures. Identification of risk factors for adverse reactions and appropriate genetic screening of groups at higher risk may improve the outcomes of skin reactions.

  9. True absorption and scattering of pions on 16O and 18O

    NASA Astrophysics Data System (ADS)

    Navon, I.; Piasetzky, E.; Ashery, D.; Altman, A.; Azuelos, G.; Schlepütz, F. W.; Walter, H. K.

    1980-10-01

    The inclusive pion inelastic scattering and true absorption cross sections on 16O and 18O were measured at 165 MeV for π± and at 315 MeV for π+. The results show large effects of the two neutrons in 18O on the absorption and inelastic scattering cross sections at the resonance energy. In particular, the inelastic scattering of π+ from 18O is considerably smaller than from 16O and this effect is attributed to the coupling between the reaction channels.

  10. Differences between Drug-Induced and Contrast Media-Induced Adverse Reactions Based on Spontaneously Reported Adverse Drug Reactions

    PubMed Central

    Suh, JinUk; Yang, MyungSuk; Kang, WonKu; Kim, EunYoung

    2015-01-01

    Objective We analyzed differences between spontaneously reported drug-induced (not including contrast media) and contrast media-induced adverse reactions. Methods Adverse drug reactions reported by an in-hospital pharmacovigilance center (St. Mary’s teaching hospital, Daejeon, Korea) from 2010–2012 were classified as drug-induced or contrast media-induced. Clinical patterns, frequency, causality, severity, Schumock and Thornton’s preventability, and type A/B reactions were recorded. The trends among causality tools measuring drug and contrast-induced adverse reactions were analyzed. Results Of 1,335 reports, 636 drug-induced and contrast media-induced adverse reactions were identified. The prevalence of spontaneously reported adverse drug reaction-related admissions revealed a suspected adverse drug reaction-reporting rate of 20.9/100,000 (inpatient, 0.021%) and 3.9/100,000 (outpatients, 0.004%). The most common adverse drug reaction-associated drug classes included nervous system agents and anti-infectives. Dermatological and gastrointestinal adverse drug reactions were most frequently and similarly reported between drug and contrast media-induced adverse reactions. Compared to contrast media-induced adverse reactions, drug-induced adverse reactions were milder, more likely to be preventable (9.8% vs. 1.1%, p < 0.001), and more likely to be type A reactions (73.5% vs. 18.8%, p < 0.001). Females were over-represented among drug-induced adverse reactions (68.1%, p < 0.001) but not among contrast media-induced adverse reactions (56.6%, p = 0.066). Causality patterns differed between the two adverse reaction classes. The World Health Organization–Uppsala Monitoring Centre causality evaluation and Naranjo algorithm results significantly differed from those of the Korean algorithm version II (p < 0.001). Conclusions We found differences in sex, preventability, severity, and type A/B reactions between spontaneously reported drug and contrast media-induced adverse

  11. Angular correlation measurements for 4-{alpha} decaying states in {sup 16}O

    SciTech Connect

    Wuosmaa, A.H.; Back, B.B.; Betts, R.R.

    1995-08-01

    Previous measurements of the {sup 12}C({sup 12}C,{sup 8}Be){sup 16}O{sup *}(4 {alpha}) reaction identified discrete levels in {sup 16}O which decay by breakup into 4 {alpha} particles through a number of different decay sequences, including {sup 16}O{sup *} {yields} {sup 8}Be + {sup 8}Be and {alpha} + {sup 12}C (O{sub 2}{sup +}). These states are observed in a range of excitation energies where resonances are observed in inelastic {alpha} + {sup 12}C scattering leading to the {sup 8}Be + {sup 8}Be and {alpha} + {sup 12}C final states. These resonances were associated with 4 {alpha}-particle chain configurations in {sup 16}O. Should the states populated in the {sup 12}C + {sup 12}C reaction possess this same extended structure, it would serve as an important piece of evidence supporting the idea that even more deformed structures are formed in the {sup 24}Mg compound system. In order to more firmly make this association, it is important to determine the spins of the states populated in the {sup 12}C + {sup 12}C reaction.

  12. Pediatric bupropion-induced serum sicknesslike reaction.

    PubMed

    Hack, Sabine

    2004-01-01

    This reports the first 2 cases of serum sicknesslike reaction to bupropion in children (age 12 and 14). Serum sicknesslike reactions are an example of immune-complex medicated disease. The cardinal symptoms of serum sickness are fever, lymphadenopathy, arthralgias or arthritis, and urticaria. Symptoms usually resolve without long-term sequela following discontinuation of the exogenous antigen. It is likely that serum sicknesslike reactions to bupropion are either relatively rare or underrecognized and underreported. Between May 1998 and May 2001, GlaxoSmith Kline received 172 reports of seizures (a well-known adverse drug reaction) and only 37 reports of serum sicknesslike reactions (Wooltorton 2002). We do not know if children and adolescents are more prone than adults to develop serum sicknesslike reactions to bupropion. Luckily, the reported cases of serum sicknesslike reactions to bupropion have not caused irreversible morbidity or mortality. Nevertheless, the symptoms are painful, temporarily disfiguring and disabling, and warrant prompt medical attention. Parents and patients should be educated about this potential side effect at the onset of treatment, because symptoms are similar to many infectious childhood illnesses, and the treatment of serum sicknesslike reactions to bupropion should include the discontinuation of bupropion.

  13. Angular distributions for /sup 16/O(/gamma/,p)/sup 15/N at intermediate energies

    SciTech Connect

    Adams, G.S.; Kinney, E.R.; Matthews, J.L.; Sapp, W.W.; Soos, T.; Owens, R.O.; Turley, R.S.; Pignault, G.

    1988-12-01

    The photoproton knockout reaction on /sup 16/O leaving /sup 15/N in low-lying bound states has been observed over the photon energy range from 196 to 361 MeV. The angular distribution for the reaction populating the ground state of /sup 15/N develops sharp structure as the photon energy is increased but that for population of the excited states is smooth. The results are not explained by existing theoretical models.

  14. Electron-induced hydration of an alkene: alternative reaction pathways.

    PubMed

    Warneke, Jonas; Wang, Ziyan; Swiderek, Petra; Bredehöft, Jan Hendrik

    2015-03-27

    Electron-induced reactions in condensed mixtures of ethylene and water lead to the synthesis of ethanol, as shown by post-irradiation thermal desorption spectrometry (TDS). Interestingly, this synthesis is not only induced by soft electron impact ionization similar to a previously observed electron-induced hydroamination but also, at low electron energy, by electron attachment to ethylene and a subsequent acid/base reaction with water.

  15. Erythropoietin-induced iritis-like reaction.

    PubMed

    Beiran, I; Krasnitz, I; Mezer, E; Meyer, E; Miller, B

    1996-01-01

    The present report describes an iritis-like reaction found in 13 patients treated with recombinant human erythropoietin (Eprex), a drug given to hemodialysis patients for their chronic anemia. Among 120 patients being treated by hemodialysis in two centers affiliated with our medical center, ten out of 30 Eprex-treated patients but none of 90 not being treated with Eprex developed this reaction. The observations described support a causal relation between Eprex treatment and the iritis-like reaction. Further investigative effort is needed to establish the mechanism.

  16. Reactions of buffers in cyanogen bromide-induced ligations.

    PubMed

    Vogel, Heike; Gerlach, Claudia; Richert, Clemens

    2013-01-01

    Rapid, template-directed ligation reactions between a phosphate-terminated oligonucleotide and an unphosphorylated reaction partner may be induced by cyanogen bromide (BrCN). Frequently, however, the reaction is low yielding, and even a large excess of the condensing agent can fail to induce quantitative conversions. In this study, we used BrCN to induce chemical primer extension reactions. Here, we report that buffers containing hydroxyl groups react with short oligodeoxynucleotides in the presence of BrCN. One stable adduct between HEPBS buffer and cytosine was characterized by mass spectrometry and NMR after HPLC purification, indicating that a side reaction occurred at this nucleobase. Further, a first example of a primer extension reaction between an unmodified oligodeoxynucleotide as primer and dGMP is reported. Together, our results shed light on the potency, as well as the drawbacks of BrCN as a highly reactive condensing reagent for the ligation of unmodified nucleic acids.

  17. Neutron-induced reaction studies using stored ions

    NASA Astrophysics Data System (ADS)

    Glorius, Jan; Litvinov, Yuri A.; Reifarth, René

    2015-11-01

    Storage rings provide unique possibilities for investigations of nuclear reactions. Radioactive ions can be stored if the ring is connected to an appropriate facility and reaction studies are feasible at low beam intensities because of the recycling of beam particles. Using gas jet or droplet targets, charged particle-induced reactions on short-lived isotopes can be studied in inverse kinematics. In such a system a high-flux reactor could serve as a neutron target extending the experimental spectrum to neutron-induced reactions. Those could be studied over a wide energy range covering the research fields of nuclear astrophysics and reactor safety, transmutation of nuclear waste and fusion.

  18. Ofloxacin Induced Cutaneous Reactions in Children.

    PubMed

    Ramani, Yerramalli Roja; Mishra, Sailen Kumar; Rath, Bandana; Rath, Saroj Sekhar

    2015-06-01

    Cutaneous adverse effects to antimicrobials are a major health problem. Though majority of them are mild and self-limiting, severe variants like Steven Johnson Syndrome (SJS), toxic epidermal necrolysis (TEN) are not uncommon. Ofloxacin, a fluoroquinolone widely used for the treatment of urinary tract infections, acute bacterial diarrheas, enteric fever, STDs and other soft tissue infections either as a single drug or in combination with other drugs. Earlier a case of mucocutaneous maculopapular rash with oral ofloxacin and was reported in an adult. In the present hospital set up there were few reports of such reactions to adults. Here we report three different variants of reactions associated with oral ofloxacin in chlidren. Early detection of cutaneous lesions and immediate withdrawal of the offending drug can prevent progression of such reactions to their severe variants as well as morbidity and mortality.

  19. Artificial Force Induced Reaction Method for Systematic Determination of Complex Reaction Mechanisms.

    PubMed

    Sameera, W M C; Kumar Sharma, Akhilesh; Maeda, Satoshi; Morokuma, Keiji

    2016-10-01

    Nowadays, computational studies are very important for the elucidation of reaction mechanisms and selectivity of complex reactions. However, traditional computational methods usually require an estimated reaction path, mainly driven by limited experimental implications, intuition, and assumptions of stationary points. However, the artificial force induced reaction (AFIR) method in the global reaction route mapping (GRRM) strategy can be used for unbiased and automatic reaction path searches for complex reactions. In this account, we highlight applications of the AFIR method to a variety of reactions (organic, organometallic, enzymatic, and photochemical) of complex molecular systems. In addition, the AFIR method has been successfully used to rationalise the origin of stereo- and regioselectivity. The AFIR method can be applied from small to large molecular systems, and will be a very useful tool for the study of complex molecular problems in many areas of chemistry, biology, and material sciences.

  20. Radiative p 16O Capture at Astrophyiscal Energies

    NASA Astrophysics Data System (ADS)

    Dubovichenko, S. B.

    2016-12-01

    Within the framework of the modified potential cluster model with forbidden states and classification of states according to the Young tableaux, the possibility is considered of describing experimental data for the astrophysical S-factor of radiative p 16O capture to the ground state of the 17F nucleus. It is shown that on the basis of E1 transitions from p 16O scattering states to the ground state of 17F in the p 16O channel overall success is achieved in explaining the magnitude of the measured cross sections at astrophysical energies.

  1. Laser-induced reactions in energetic materials

    NASA Astrophysics Data System (ADS)

    Ling, Ping

    1999-07-01

    Several energetic materials have been investigated under shock wave loading, heating, and photodissociation. This dissertation highlights some efforts to understand energetic material from an angle of basic physical processes and elementary chemical reactions. The first series of experiments was performed to study laser-generated shock waves in energetic materials. Shock waves are generated by pulsed laser vaporization of thin aluminum films. The rapidly expanding aluminum plasma launches a shock wave into the adjacent layer of energetic material, initiating chemical reactions. The shock velocity has been measured by a velocity interferometer. Shock pressures as high as 8 GPa have been generated in this manner. A simple model is proposed to predict laser-generated shock pressure. Several energetic materials have been studied under laser- generated shock wave. The second series of experiments was conducted to study thermal decomposition and photodissociation of energetic materials. Glycidyl azide polymer (GAP) and poly(glycidyl nitrate) (PGN) have been investigated by pulsed infrared laser pyrolysis and ultraviolet laser photolysis of thin films at 17-77 K. Reactions are monitored by transmission infrared spectroscopy. Photolysis of GAP at 266 nm shows that the initial reaction steps are elimination of molecular nitrogen with subsequent formation of imines. Thermal decomposition of GAP by infrared laser pyrolysis reveals products similar to the UV experiments after warming. Laser pyrolysis of PGN indicated that the main steps of decomposition are elimination of NO2 and CH2O from the nitrate ester functional group. It seems that the initial thermal decomposition mechanism of GAP and PGN are the same from heating rate of several degrees per second to 107 oC/s. The third series of experiments is about detailed study of photodissociation mechanism of methyl nitrate. Photodissociation of methyl nitrate isolated in an argon matrix at 17 K has been investigated by 266 nm

  2. Large and unexpected enrichment in stratospheric 16O13C18O and its meridional variation

    PubMed Central

    Yeung, Laurence Y.; Affek, Hagit P.; Hoag, Katherine J.; Guo, Weifu; Wiegel, Aaron A.; Atlas, Elliot L.; Schauffler, Sue M.; Okumura, Mitchio; Boering, Kristie A.; Eiler, John M.

    2009-01-01

    The stratospheric CO2 oxygen isotope budget is thought to be governed primarily by the O(1D)+CO2 isotope exchange reaction. However, there is increasing evidence that other important physical processes may be occurring that standard isotopic tools have been unable to identify. Measuring the distribution of the exceedingly rare CO2 isotopologue 16O13C18O, in concert with 18O and 17O abundances, provides sensitivities to these additional processes and, thus, is a valuable test of current models. We identify a large and unexpected meridional variation in stratospheric 16O13C18O, observed as proportions in the polar vortex that are higher than in any naturally derived CO2 sample to date. We show, through photochemical experiments, that lower 16O13C18O proportions observed in the midlatitudes are determined primarily by the O(1D)+CO2 isotope exchange reaction, which promotes a stochastic isotopologue distribution. In contrast, higher 16O13C18O proportions in the polar vortex show correlations with long-lived stratospheric tracer and bulk isotope abundances opposite to those observed at midlatitudes and, thus, opposite to those easily explained by O(1D)+CO2. We believe the most plausible explanation for this meridional variation is either an unrecognized isotopic fractionation associated with the mesospheric photochemistry of CO2 or temperature-dependent isotopic exchange on polar stratospheric clouds. Unraveling the ultimate source of stratospheric 16O13C18O enrichments may impose additional isotopic constraints on biosphere–atmosphere carbon exchange, biosphere productivity, and their respective responses to climate change. PMID:19564595

  3. Computational Catalysis Using the Artificial Force Induced Reaction Method.

    PubMed

    Sameera, W M C; Maeda, Satoshi; Morokuma, Keiji

    2016-04-19

    The artificial force induced reaction (AFIR) method in the global reaction route mapping (GRRM) strategy is an automatic approach to explore all important reaction paths of complex reactions. Most traditional methods in computational catalysis require guess reaction paths. On the other hand, the AFIR approach locates local minima (LMs) and transition states (TSs) of reaction paths without a guess, and therefore finds unanticipated as well as anticipated reaction paths. The AFIR method has been applied for multicomponent organic reactions, such as the aldol reaction, Passerini reaction, Biginelli reaction, and phase-transfer catalysis. In the presence of several reactants, many equilibrium structures are possible, leading to a number of reaction pathways. The AFIR method in the GRRM strategy determines all of the important equilibrium structures and subsequent reaction paths systematically. As the AFIR search is fully automatic, exhaustive trial-and-error and guess-and-check processes by the user can be eliminated. At the same time, the AFIR search is systematic, and therefore a more accurate and comprehensive description of the reaction mechanism can be determined. The AFIR method has been used for the study of full catalytic cycles and reaction steps in transition metal catalysis, such as cobalt-catalyzed hydroformylation and iron-catalyzed carbon-carbon bond formation reactions in aqueous media. Some AFIR applications have targeted the selectivity-determining step of transition-metal-catalyzed asymmetric reactions, including stereoselective water-tolerant lanthanide Lewis acid-catalyzed Mukaiyama aldol reactions. In terms of establishing the selectivity of a reaction, systematic sampling of the transition states is critical. In this direction, AFIR is very useful for performing a systematic and automatic determination of TSs. In the presence of a comprehensive description of the transition states, the selectivity of the reaction can be calculated more accurately

  4. Noise-induced transition in human reaction times

    NASA Astrophysics Data System (ADS)

    Medina, José M.; Díaz, José A.

    2016-09-01

    The human reaction/response time can be defined as the time elapsed from the onset of stimulus presentation until a response occurs in many sensory and cognitive processes. A reaction time model based on Piéron’s law is investigated. The model shows a noise-induced transition in the moments of reaction time distributions due to the presence of strong additive noise. The model also demonstrates that reaction times do not follow fluctuation scaling between the mean and the variance but follow a generalized version between the skewness and the kurtosis. The results indicate that noise-induced transitions in the moments govern fluctuations in sensory-motor transformations and open an insight into the macroscopic effects of noise in human perception and action. The conditions that lead to extreme reaction times are discussed based on the transfer of information in neurons.

  5. Airy structure in 16O+14C nuclear rainbow scattering

    NASA Astrophysics Data System (ADS)

    Ohkubo, S.; Hirabayashi, Y.

    2015-08-01

    The Airy structure in 16 O +14 C rainbow scattering is studied with an extended double-folding (EDF) model that describes all the diagonal and off-diagonal coupling potentials derived from the microscopic realistic wave functions for 16 O by using a density-dependent nucleon-nucleon force. The experimental angular distributions at EL=132 , 281, and 382.2 MeV are well reproduced by the calculations. By studying the energy evolution of the Airy structure, the Airy minimum around θ =76∘ in the angular distribution at EL=132 MeV is assigned as the second-order Airy minimum A 2 in contrast to the recent literature which assigns it as the third order A 3 . The Airy minima in the 90∘ excitation function is investigated in comparison with well-known 16 O +16 O and 12 C +12 C systems. Evolution of the Airy structure into the molecular resonances with the 16 O +14 C cluster structure in the low-energy region around Ec .m .=30 MeV is discussed. It is predicted theoretically for the first time for a non-4 N 16O +14 C system that Airy elephants in the 90∘ excitation function are present.

  6. On laser-induced harpooning reactions

    NASA Astrophysics Data System (ADS)

    Weiner, J.

    1980-05-01

    In the present paper, the switching of chemical reactivity by a nonresonant laser field in simple gas-phase collisions of the type A + BC to AB + C is discussed in terms of a second-order optical/collision perturbation. A simple expression relating laser-induced harpooning cross sections to the laser power density is derived and is applied to Hg/Cl2 collisions.

  7. Cinnamon-induced Oral Mucosal Contact Reaction

    PubMed Central

    Vivas, Ana P. M; Migliari, Dante A

    2015-01-01

    Contact stomatitis associated with consumption of cinnamon flavoring agents is a relatively uncommon disorder. Of relevance, both clinical features and the histopathologic findings of this condition are nonspecific, and, more importantly, may resemble some other inflammatory oral mucosa disorders, eventually making diagnosis difficult. Usually a patient exhibits a combination of white and erythematous patches of abrupt onset, accompanied by a burning sensation. To shed some light on this subject, a case of a 64-year-old woman with hypersensitivity contact reaction on the oral mucosa due to cinnamon mints is presented, with emphasis on differential diagnosis and the process for confirmation of the diagnosis. The treatment consists of discontinuing the use of cinnamon products. Clinicians will be able to recognize this disorder following a careful clinical examination and detailed history. This recognition is important in order to avoid invasive and expensive diagnostic procedures. PMID:26312097

  8. Measuring Neutron-Induced Reaction Cross Sections without Neutrons

    NASA Astrophysics Data System (ADS)

    Bernstein, L. A.; Schiller, A.; Cooper, J. R.; Hoffman, R. D.; McMahan, M. A.; Fallon, P.; Macchiavelli, A. O.; Mitchell, G.; Tavukcu, E.; Guttormsen, M.

    2003-04-01

    Neutron-induced reactions on radioactive nuclei play a significant role in nuclear astrophysics and many other applied nuclear physics topics. However, the majority of these cross sections are impossible to measure due to the high-background of the targets and the low-intensity of neutron beams. We have explored the possibility of using charged-particle transfer reactions to form the same "pre-compound" nucleus as one formed in a neutron-induced reaction in order to measure the relative decay probabilities of the nucleus as a function of energy. Multiplying these decay probabilities by the neutron absorption cross section will then produce the equivalent neutron-induced reaction cross section. In this presentation I will explore the validity of this "surrogate reaction" technique by comparing results from the recent 157Gd(3He,axng)156-xGd experiment using STARS (Silicon Telescope Array for Reaction Studies) at GAMMASPHERE with reaction model calculations for the 155Gd(n,xng)156-xGd. This work was funded by the US Department of Energy under contracts number W-7405-ENG-48 (LLNL), AC03-76SF00098 (LBNL) and the Norwegian Research Council (Oslo).

  9. Evidence of Vibrational-Induced Rotational Axis Switching for HD 12C 16O: New High-Resolution Analysis of the ν 5 and ν 6 Bands and First Analysis of the ν 4 Band (10-μm Region)

    NASA Astrophysics Data System (ADS)

    Perrin, A.; Flaud, J.-M.; Smirnov, M.; Lock, M.

    2000-09-01

    Using new high-resolution Fourier transform spectra recorded in Giessen in the 8-12 μm region, a more extended analysis of the ν5 and ν6 bands and the first high-resolution study of the ν4 band of HDCO were performed. As pointed out previously [M. Allegrini, J. W. C. Johns, and A. R. W. McKellar, Can. J. Phys. 56, 859-864 (1978)], the energy levels of the 51 and 61 states are strongly coupled by A- and B-type Coriolis interactions. On the other hand, it appeared that weaker resonances involving the energy levels of the 41 state with those of the 51 and 61 states also had to be accounted for. Consequently, the calculation of the energy levels was performed taking into account the Coriolis-type resonances linking the energy levels of the {61, 51, 41} resonating states. Because of the unusually strong Coriolis interaction between ν5 and ν6, a nonclassical behavior of the rotational levels of the 51 and 61 states was observed and it was necessary to use a new Hamiltonian matrix which possesses, as usual, both A- and B-type Coriolis operators in the 51 ⇔ 61 and 61 ⇔ 41 off diagonal blocks but differs from the classical reduced Hamiltonian which is used commonly for planar Cs-type molecules. More precisely, it proved necessary to include non-orthorhombic terms in the expansion of the rotational Hamiltonian of the 51 and 61 states. According to the considerations developed by Watson [J. K. G. Watson, in 'Vibrational Spectra and Structure,' (J. Durig, Ed.), Chap. 1, Elsevier, Amsterdam, 1977], these non-orthorhombic operators which are not symmetry forbidden are usually removed for semirigid Cs-type molecules by rotational contact transformations. In the present study, the occurrence of terms in {Jx, Jz} in the expansions of the rotational Hamiltonians for the 51 and 61 states indicates that the inertial system of HDCO differs for each of the three {61, 51, 41} resonating states. Therefore, HDCO becomes a good example of vibrational-induced rotational axis

  10. Locomotion of electrocatalytic nanomotors due to reaction induced charge autoelectrophoresis

    NASA Astrophysics Data System (ADS)

    Moran, J. L.; Wheat, P. M.; Posner, J. D.

    2010-06-01

    Bimetallic rod-shaped nanomotors swim autonomously in hydrogen peroxide solutions. Here, we present a scaling analysis, computational simulations, and experimental data that show that the nanomotor locomotion is driven by fluid slip around the nanomotor surface due to electrical body forces. The body forces are generated by a coupling of charge density and electric fields induced by electrochemical reactions occurring on the nanomotor surface. We describe the dependence of nanomotor motion on the nanomotor surface potential and reaction-driven flux.

  11. Nuclear reactions induced by high-energy alpha particles

    NASA Technical Reports Server (NTRS)

    Shen, B. S. P.

    1974-01-01

    Experimental and theoretical studies of nuclear reactions induced by high energy protons and heavier ions are included. Fundamental data needed in the shielding, dosimetry, and radiobiology of high energy particles produced by accelerators were generated, along with data on cosmic ray interaction with matter. The mechanism of high energy nucleon-nucleus reactions is also examined, especially for light target nuclei of mass number comparable to that of biological tissue.

  12. Deuterium separation by infrared-induced addition reaction

    DOEpatents

    Marling, John B.

    1977-01-01

    A method for deuterium enrichment by the infrared-induced addition reaction of a deuterium halide with an unsaturated aliphatic compound. A gaseous mixture of a hydrogen halide feedstock and an unsaturated aliphatic compound, particularly an olefin, is irradiated to selectively vibrationally excite the deuterium halide contained therein. The excited deuterium halide preferentially reacts with the unsaturated aliphatic compound to produce a deuterated addition product which is removed from the reaction mixture.

  13. On reaction mechanisms involved in the deuteron–induced surrogate reactions

    SciTech Connect

    Avrigeanu, M.; Avrigeanu, V.; Mănăilescu, C.

    2015-02-24

    An extended analysis of the nuclear reaction mechanisms involved within deuteron interaction with nuclei, namely the breakup, stripping, pick-up, pre-equilibrium emission, and evaporation from fully equilibrated compound nucleus, is presented in order to highlight the importance of the direct mechanisms still neglected in the analysis of deuteron-induced surrogate reactions. Particularly, the dominance of the breakup mechanism at low energies around the Coulomb barrier should be considered in the case of (d,x) surrogate reactions on actinide target nuclei.

  14. Dynamics of synchrotron VUV-induced intracluster reactions

    SciTech Connect

    Grover, J.R.

    1993-12-01

    Photoionization mass spectrometry (PIMS) using the tunable vacuum ultraviolet radiation available at the National Synchrotron Light Source is being exploited to study photoionization-induced reactions in small van der Waals mixed complexes. The information gained includes the observation and classification of reaction paths, the measurement of onsets, and the determination of relative yields of competing reactions. Additional information is obtained by comparison of the properties of different reacting systems. Special attention is given to finding unexpected features, and most of the reactions investigated to date display such features. However, understanding these reactions demands dynamical information, in addition to what is provided by PIMS. Therefore the program has been expanded to include the measurement of kinetic energy release distributions.

  15. Contraband detection using high-energy gamma rays from 16O*

    NASA Astrophysics Data System (ADS)

    Micklich, Bradley J.; Fink, Charles L.; Sagalovsky, Leonid; Smith, Donald L.

    1997-02-01

    High-energy monoenergetic gamma rays (6.13 and 7.12 MeV) from the decay of excited states of the 16O* nucleus are highly penetrating and thus offer potential for non- intrusive inspection of loaded containers for narcotics, explosives, and other contraband items. These excited states can be produced by irradiation of water with 14-MeV neutrons from a DT neutron generator or through the 19F(p,alpha)16O* reaction. Resonances in 19F(p,alpha)16O* at proton energies between 340 keV and 2 MeV allow use of a low-energy accelerator to provide a compact, portable gamma source of reasonable intensity. The present work provides estimates of gamma source parameters and suggests how various types of contraband could be detected. Gamma rays can be used to perform transmission or emission radiography of containers or other objects. Through the use of (gamma,n) and (gamma,fission) reactions, this technique is also capable of detecting special nuclear materials such as deuterium, lithium, beryllium, uranium, and plutonium. Analytic and Monte Carlo techniques are used to model empty and loaded container inspection for accelerator-produced gamma, radioisotope, and x-ray sources.

  16. Contraband detection using high-energy gamma rays from {sup 16}O*

    SciTech Connect

    Micklich, B.J.; Fink, C.L.; Sagalovsky, L.; Smith, D.L.

    1996-12-01

    High-energy monoenergetic gamma rays (6.13 and 7.12 MeV) from the decay of excited states of the {sup 16}O* nucleus are highly penetrating and thus offer potential for non-intrusive inspection of loaded containers for narcotics, explosives, and other contraband items. These excited states can be produced by irradiation of water with 14-MeV neutrons from a DT neutron generator or through the {sup 19}F(p,{alpha}){sup 16}O* reaction. Resonances in {sup 19}F(p,{alpha}){sup 16}O* at proton energies between 340 keV and 2 MeV allow use of a low-energy accelerator to provide a compact, portable gamma source of reasonable intensity. The present work provides estimates of gamma source parameters and suggests how various types of contraband could be detected. Gamma rays can be used to perform transmission or emission radiography of containers or other objects. Through the use of ({gamma}, n) and ({gamma}, fission) reactions, this technique is also capable of detecting special nuclear materials such as deuterium, lithium, beryllium, uranium, and plutonium. Analytic and Monte Carlo techniques are used to model empty and loaded container inspection for accelerator-produced gamma, radioisotope, and x-ray sources.

  17. Characterization of the proposed 4 -α cluster state candidate in 16O

    NASA Astrophysics Data System (ADS)

    Li, K. C. W.; Neveling, R.; Adsley, P.; Papka, P.; Smit, F. D.; Brümmer, J. W.; Diget, C. Aa.; Freer, M.; Harakeh, M. N.; Kokalova, Tz.; Nemulodi, F.; Pellegri, L.; Rebeiro, B.; Swartz, J. A.; Triambak, S.; van Zyl, J. J.; Wheldon, C.

    2017-03-01

    The 16O(α ,α') reaction was studied at θlab=0∘ at an incident energy of Elab=200 MeV using the K600 magnetic spectrometer at iThemba LABS. Proton decay and α decay from the natural parity states were observed in a large-acceptance silicon strip detector array at backward angles. The coincident charged-particle measurements were used to characterize the decay channels of the 06+ state in 16O located at Ex=15.097 (5 ) MeV. This state is identified by several theoretical cluster calculations to be a good candidate for the 4 -α cluster state. The results of this work suggest the presence of a previously unidentified resonance at Ex≈15 MeV that does not exhibit a 0+ character. This unresolved resonance may have contaminated previous observations of the 06+ state.

  18. Spectroscopy of {sup 16}O Using {alpha}+{sup 12}C Resonant Scattering in Inverse Kinematics

    SciTech Connect

    Ashwood, N. I.; Freer, M.; Bloxham, T. R.; Curtis, N.; Haigh, P. J.; Price, D. L.; Achouri, N. L.; Catford, W. N.; Harlin, C. W.; Patterson, N. P.; Thomas, J. S.; Soic, N.

    2009-08-26

    A measurement of the {alpha}({sup 12}C,{alpha}){sup 12}C reaction has been performed using resonant scattering with a gas target. Beam energies of 46, 51, 56 and 63 MeV were used to populate resonances in the excitation energy range of 11.6 to 22.9 MeV in {sup 16}O. The angular distributions of the elastic scattering were measured at zero degrees using an array of segmented silicon strip detectors with a minimum range of 0 deg. to 30 deg. in the centre of mass. The spins of 8 resonances between 14.1 and 18.5 MeV were obtained, confirming spin assignments made using elastic scattering in normal kinematics. An R-matrix analysis of the data was performed which indicates that the present understanding of {sup 16}O in this region is good, but not complete.

  19. Tween-80 and impurity induce anaphylactoid reaction in zebrafish.

    PubMed

    Yang, Rui; Lao, Qiao-Cong; Yu, Hang-Ping; Zhang, Yong; Liu, Hong-Cui; Luan, Lin; Sun, Hui-Min; Li, Chun-Qi

    2015-03-01

    A number of recent reports suspected that Tween-80 in injectable medicines, including traditional Chinese medicine injections could cause life-threatening anaphylactoid reaction, but no sound conclusion was drawn. A drug-induced anaphylactoid reaction is hard to be assayed in vitro and in conventional animal models. In this study, we developed a microplate-based quantitative in vivo zebrafish assay for assessing anaphylactoid reaction and live whole zebrafish mast cell tryptase activity was quantitatively measured at a wavelength of 405 nm using N-benzoyl-dl-arginine p-nitroanilide as a substrate. We assessed 10 batches of Tween-80 solutions from various national and international suppliers and three Tween-80 impurities (ethylene glycol, 2-chloroethanol and hydrogen peroxide) in this model and found that three batches of Tween-80 (nos 2, 20080709 and 20080616) and one Tween-80 impurity, hydrogen peroxide (H2 O2 ), induced anaphylactoid reactions in zebrafish. Furthermore, we found that H2 O2 residue and peroxide value were much higher in Tween-80 samples 2, 20080709 and 20080616. These findings suggest that H2 O2 residue in combination with oxidized fatty acid residues (measured as peroxide value) or more likely the oxidized fatty acid residues in Tween-80 samples, but not Tween-80 itself, may induce anaphylactoid reaction. High-throughput zebrafish tryptase assay developed in this report could be used for assessing safety of Tween-80-containing injectable medicines and potentially for screening novel mast cell-modulating drugs.

  20. 16O + 16O molecular structures of positive- and negative-parity superdeformed bands in 34S

    NASA Astrophysics Data System (ADS)

    Taniguchi, Yasutaka

    2016-05-01

    The structures of excited states in 34S are investigated using the antisymmetrized molecular dynamics and generator coordinate method(GCM). The GCM basis wave functions are calculated via energy variation with a constraint on the quadrupole deformation parameter β. By applying the GCM after parity and angular momentum projections, the coexistence of two positive- and one negative-parity super de formed(SD) bands are predicted, and low-lying states and other deformed bands are obtained. The SD bands have structures of 16O + 16O + two valence neutrons in molecular orbitals around the two 16O cores in a cluster picture. The configurations of the two valence neutrons are δ2 and π2 for the positive-parity SD bands and π1δ1 for the negative parity SD band.

  1. Mechanisms of shock-induced reactions in high explosives

    NASA Astrophysics Data System (ADS)

    Kay, Jeffrey J.

    2017-01-01

    Understanding the mechanisms by which shock waves initiate chemical reactions in explosives is key to understanding their unique and defining property: the ability to undergo rapid explosive decomposition in response to mechanical stimulus. Although shock-induced reactions in explosives have been studied experimentally and computationally for decades, the nature of even the first chemical reactions that occur in response to shock remain elusive. To predictively understand how explosives respond to shock, the detailed sequence of events that occurs - mechanical deformation, energy transfer, bond breakage, and first chemical reactions - must be understood at the quantum-mechanical level. This paper reviews recent work in this field and ongoing experimental and theoretical work at Sandia National Laboratories in this important area of explosive science.

  2. Photo-induced chemical reaction of trans-resveratrol.

    PubMed

    Zhao, Yue; Shi, Meng; Ye, Jian-Hui; Zheng, Xin-Qiang; Lu, Jian-Liang; Liang, Yue-Rong

    2015-03-15

    Photo-induced chemical reaction of trans-resveratrol has been studied. UV B, liquid state and sufficient exposure time are essential conditions to the photochemical change of trans-resveratrol. Three principal compounds, cis-resveratrol, 2,4,6-phenanthrenetriol and 2-(4-hydroxyphenyl)-5,6-benzofurandione, were successively generated in the reaction solution of trans-resveratrol (0.25 mM, 100% ethanol) under 100 μW cm(-2) UV B radiation for 4h. cis-Resveratrol, originated from isomerization of trans-resveratrol, resulted in 2,4,6-phenanthrenetriol through photocyclisation reaction meanwhile loss of 2 H. 2,4,6-Phenanthrenetriol played a role of photosensitizer producing singlet oxygen in the reaction pathway. The singlet oxygen triggered [4+2] cycloaddition reaction of trans-resveratrol, and then resulted in the generation of 2-(4-hydroxyphenyl)-5,6-benzofurandione through photorearrangement and oxidation reaction. The singlet oxygen reaction was closely related to the substrate concentration of trans-resveratrol in solution.

  3. Phenomenological and semi-microscopic analysis for 16O and 12C elastically scattering on the nucleus of 16O and 12C at Energies near the Coulomb barrier

    NASA Astrophysics Data System (ADS)

    Hamada, Sh; Burtebayev, N.; Amangeldi, N.; Gridnev, K. A.; Rusek, K.; Kerimkulov, Zh; Maltsev, N.

    2012-09-01

    The nuclear burning process proceeds from the conservation of the most abundant element hydrogen to helium, then from helium to carbon and oxygen, and then from these to heavier elements. Some of the key reactions for the carbon and oxygen burning stages of the nucleosynthesis are 12C+12C and 16O+16O leading to all possible final states. This paper contains the experimental measurements of 12C+12C and 16O+16O angular distributions performed at the cyclotron DC-60 in Astana, Kazakhstan. The extracted beam of 16O and 12C was accelerated up to two energies 1.75 and 1.5 MeV/n and then directed to an Al2O3 target of thickness 20 μg/cm2 and a carbon self-supporting target of thickness 17.4 μg/cm2. The angular distribution calculations were performed using both the phenomenological optical potential (SPI-GENOA) code and the double folding potential (FRESCO) code.

  4. Systematic measurements of proton-induced reactions on enriched molybdenum

    NASA Astrophysics Data System (ADS)

    Lamere, Edward; Gilardy, Gwenaelle; Meisel, Zach; Moran, Michael; Seymore, Christopher; Skulski, Michael; Simonetti, Antonio; Couder, Manoel

    2016-09-01

    Between 2008 and 2010, shortages in the world-wide supply of Mo highlighted weaknesses in the current fission-based production method of mTc, a critical medical isotope. This crisis sparked interest in developing the direct production of mTc from proton-induced reactions on enriched Mo targets as an alternative. One complication with this method is that mTc must be chemically extracted from the irradiated target. Therefore, radiopharmaceuticals produced from proton bombardment will contain a mixture of all Tc-species with open production channels, affecting radiochemical purity, specific activity and total production yield of mTc-factors critical for the feasibility of this production method. Reactions on trace impurities in the enriched targets have been shown to impact these factors dramatically. Precise cross-section measurements for all Mo +p reactions that lead to Tc or Mo species are required for proper assessment of this production technique. Cross-section measurements for the main reaction of interest, mTc(p,2n), have been performed in recent years, however, other reactions producing Tc have been mostly neglected. We will introduce a systematic study of proton-induced reactionson 92, 94-98, 100 Mo currently being performed at Notre Dame. Preliminary results will be presented. NRC-HQ-12-G-38-0073.

  5. A non-terrestrial 16O-rich isotopic composition for the protosolar nebula.

    PubMed

    Hashizume, Ko; Chaussidon, Marc

    2005-03-31

    The discovery in primitive components of meteorites of large oxygen isotopic variations that could not be attributed to mass-dependent fractionation effects has raised a fundamental question: what is the composition of the protosolar gas from which the host grains formed? This composition is probably preserved in the outer layers of the Sun, but the resolution of astronomical spectroscopic measurements is still too poor to be useful for comparison with planetary material. Here we report a precise determination of the oxygen isotopic composition of the solar wind from particles implanted in the outer hundreds of nanometres of metallic grains in the lunar regolith. These layers of the grains are enriched in 16O by >20 +/- 4 per thousand relative to the Earth, Mars and bulk meteorites, which implies the existence in the solar accretion disk of reactions--as yet unknown--that were able to change the 17O/16O and 18O/16O ratios in a way that was not dependent strictly on the mass of the isotope. Photochemical self-shielding of the CO gas irradiated by ultraviolet light may be one of these key processes, because it depends on the abundance of the isotopes, rather than their masses.

  6. Oral Muscle Relaxant May Induce Immediate Allergic Reactions

    PubMed Central

    Hur, Gyu-Young; Hwang, Eui Kyung; Moon, Jae-Young; Ye, Young-Min; Shim, Jae-Jeong; Kang, Kyung-Ho

    2012-01-01

    Eperisone and afloqualone act by relaxing both skeletal and vascular smooth muscles to improve circulation and suppress pain reflex. These drugs are typically prescribed with non-steroidal anti-inflammatory drugs (NSAIDs) as painkillers. However, there have been no reports on serious adverse reactions to oral muscle relaxants; and this is the first report to describe three allergic reactions caused by eperisone and afloqualone. All three patients had histories of allergic reactions after oral intake of multiple painkillers, including oral muscle relaxants and NSAIDs, for chronic muscle pain. An open-label oral challenge test was performed with each drug to confirm which drugs caused the systemic reactions. All patients experienced the same reactions within one hour after oral intake of eperisone or afloqualone. The severity of these reactions ranged from laryngeal edema to hypotension. To confirm that the systemic reaction was caused by eperisone or afloqualone, skin prick testing and intradermal skin tests were performed with eperisone or afloqualone extract in vivo, and basophil activity tests were performed after stimulation with these drugs in vitro. In one patient with laryngeal edema, the intradermal test with afloqualone extract had a positive result, and CD63 expression levels on basophils increased in a dose-dependent manner by stimulation with afloqualone. We report three allergic reactions caused by oral muscle relaxants that might be mediated by non-immunoglobulin E-mediated responses. Since oral muscle relaxants such as eperisone and afloqualone are commonly prescribed for chronic muscle pain and can induce severe allergic reactions, we should prescribe them carefully. PMID:22665359

  7. A systematic review of drug induced ocular reactions in diabetes

    PubMed Central

    Hampson, J; Harvey, J

    2000-01-01

    AIMS—To conduct a systematic review of drug induced adverse ocular effects in diabetes to determine if this approach identified any previously unrecognised adverse drug effects; to make a preliminary assessment of the feasibility of this approach in identifying adverse drug reactions; and to assess the current accessibility of this information to prescribing physicians.
METHODS—Literature search of online biomedical databases. The search strategy linked eye disorders with adverse drug reactions and diabetes. Source journals were classified as medical, pharmaceutical, diabetes related, or ophthalmological. It was determined whether the reactions identified were recorded in drug datasheets and the British National Formulary.
RESULTS—63 references fulfilled the selection criteria, of which 45 were considered to be relevant to the study. The majority of these were case reports but cross sectional surveys, case-control and cohort studies, and review articles were also identified. 61% of the reactions were not recorded in the British National Formulary and 41% were not recorded in the datasheets. 55% appeared in specialist ophthalmology journals.
CONCLUSIONS—This is a feasible approach to the identification of adverse drug reactions. Adverse reactions not listed in the most commonly used reference sources were found. The majority were published in specialist ophthalmology journals which might not be seen by prescribing physicians.

 PMID:10655188

  8. Chemical memory reactions induced bursting dynamics in gene expression.

    PubMed

    Tian, Tianhai

    2013-01-01

    Memory is a ubiquitous phenomenon in biological systems in which the present system state is not entirely determined by the current conditions but also depends on the time evolutionary path of the system. Specifically, many memorial phenomena are characterized by chemical memory reactions that may fire under particular system conditions. These conditional chemical reactions contradict to the extant stochastic approaches for modeling chemical kinetics and have increasingly posed significant challenges to mathematical modeling and computer simulation. To tackle the challenge, I proposed a novel theory consisting of the memory chemical master equations and memory stochastic simulation algorithm. A stochastic model for single-gene expression was proposed to illustrate the key function of memory reactions in inducing bursting dynamics of gene expression that has been observed in experiments recently. The importance of memory reactions has been further validated by the stochastic model of the p53-MDM2 core module. Simulations showed that memory reactions is a major mechanism for realizing both sustained oscillations of p53 protein numbers in single cells and damped oscillations over a population of cells. These successful applications of the memory modeling framework suggested that this innovative theory is an effective and powerful tool to study memory process and conditional chemical reactions in a wide range of complex biological systems.

  9. Ofloxacin Induced Angioedema: A Rare Adverse Drug Reaction

    PubMed Central

    Yadav, Sankalp; Kumar, Raj; Wani, Umar Rasool

    2016-01-01

    The Adverse Drug Reaction (ADR) to a commonly prescribed anti-microbial can pose a major public health problem. The authors report a rare case of 24-year-old young lady who presented with angioedema of lips after ingestion of Ofloxacin, prescribed to her for treatment of loose motions. Fluoroquinolones are widely prescribed antibiotics for various disease conditions. The history, clinical examination and normal laboratory parameters led to the diagnosis of ofloxacin induced hypersensitivity reaction and the patient was successfully treated with corticosteroids and antihistamines. The hypersensitivity reactions to fluoroquinolones are rare with an incidence of 0.4% to 2%. The pharmacovigilance program and self-reporting of all the ADR’s by the health care workers can help in ensuring the judicious use of the drug, drug safety and thus decrease the associated morbidity and mortality. PMID:28050397

  10. Photo-induced electron-transfer reactions in heterogeneous media

    NASA Astrophysics Data System (ADS)

    Yang, J. M.

    1981-11-01

    The conversion of solar energy into chemical energy was pursued by two approaches. One is the photo-induced electron transfer reactions in heterogeneous media, and the other is the photo-decomposition of water with liquid-junction solar cells. Photo-induced electron-transfer reactions in heterogeneous media with colloidal silica or poly-acrylate were studied by flash photolysis. In an effort to illustrate that small band-gap semiconductors can be protected from photo-corrosion through surface modification, the surface of polycrystalline ZnO was chemically coated with zinc phthalocyanine and the electron-transfer process across the coated ZnO-electrolyte interface was studied by photo-electrochemical techniques.

  11. Dynamical isospin effects in nucleon-induced reactions

    SciTech Connect

    Ou Li; Li Zhuxia; Wu Xizhen

    2008-10-15

    The isospin effects in proton-induced reactions on isotopes of {sup 112-132}Sn and the corresponding {beta}-stable isobars are studied by means of the improved quantum molecular dynamics model and some sensitive probes for the density dependence of the symmetry energy at subnormal densities are proposed. The beam energy range is chosen to be 100-300 MeV. Our study shows that the system size dependence of the reaction cross sections for p+{sup 112-132}Sn deviates from the Carlson's empirical expression obtained by fitting the reaction cross sections for proton on nuclei along the {beta}-stability line and sensitively depends on the stiffness of the symmetry energy. We also find that the angular distribution of elastic scattering for p+{sup 132}Sn at large impact parameters is very sensitive to the density dependence of the symmetry energy, which is uniquely due to the effect of the symmetry potential with no mixture of the effect from the isospin dependence of the nucleon-nucleon cross sections. The isospin effects in neutron-induced reactions are also studied and it is found that the effects are just opposite to that in proton-induced reactions. We find that the difference between the peaks of the angular distributions of elastic scattering for p+{sup 132}Sn and n+{sup 132}Sn at E{sub p,n}=100 MeV and b=7.5 fm is positive for soft symmetry energy U{sub sym}{sup sf} and negative for super-stiff symmetry energy U{sub sym}{sup nlin} and close to zero for linear density dependent symmetry energy U{sub sym}{sup lin}, which seems very useful for constraining the density dependence of the symmetry energy at subnormal densities.

  12. 12C+16O sub-barrier radiative capture cross-section measurements

    NASA Astrophysics Data System (ADS)

    Goasduff, A.; Courtin, S.; Haas, F.; Lebhertz, D.; Jenkins, D. G.; Beck, C.; Fallis, J.; Ruiz, C.; Hutcheon, D. A.; Amandruz, P.-A.; Davis, C.; Hager, U.; Ottewell, D.; Ruprecht, G.

    2011-10-01

    We have performed a heavy ion radiative capture reaction between two light heavy ions, 12C and 16O, leading to 28Si. The present experiment has been performed below Coulomb barrier energies in order to reduce the phase space and to try to shed light on structural effects. Obtained γ-spectra display a previously unobserved strong feeding of intermediate states around 11 MeV at these energies. This new decay branch is not fully reproduced by statistical nor semi-statistical decay scenarii and may imply structural effects. Radiative capture cross-sections are extracted from the data.

  13. The CW-CRDS spectra of the 16O/18O isotopologues of ozone between 5930 and 6340 cm-1—Part 3: 16O18O18O and 18O16O18O

    NASA Astrophysics Data System (ADS)

    De Backer, M.-R.; Barbe, A.; Starikova, E.; Tyuterev, Vl. G.; Mondelain, D.; Kassi, S.; Campargue, A.

    2013-09-01

    Our systematic investigation of the high sensitivity CW-Cavity Ring Down Spectra of 16O/18O ozone isotopologues at high vibrational excitation continues with the study of the 16O18O18O and 18O16O18O species. The first two papers of this series were devoted to the analysis of the same four bands of the 16O16O18O and 16O18O16O species in the 5930-6340 cm-1domain. Here, after a brief reminder of relevant experiment and theory, we report the analyses of two bands of 16O18O18O, vibrationally assigned as 2ν2+5ν3 and 2ν1+2ν2+3ν3_2 and three bands of 18O16O18O, assigned to 2ν1+2ν2+3ν3_1, 5ν1+ν3 and 3ν1+ν2+3ν3.They correspond to the highest vibration excitations observed so far for the 16O18O18O and 18O16O18O isotopologues. Altogether for the two new bands of 16O18O18O, 1214 rovibrational transitions were assigned up to Jmax=29 and for the three new bands of 18O16O18O, 948 rovibrational transitions were assigned up to Jmax=27. Observed line positions were fitted with root-mean squares deviations ranging from 0.005 to 0.011 cm-1, using effective Hamiltonian models accounting for dark state perturbations. The derived band centres and rotational constants are in good agreement with new theoretical calculations from the molecular potential function. The corresponding lists of 3365 lines are provided as Supplementary material.

  14. Effect of dexmedetomidine priming on convulsion reaction induced by lidocaine.

    PubMed

    Wang, Xi-Feng; Luo, Xiao-Ling; Liu, Wei-Cheng; Hou, Ben-Chao; Huang, Jian; Zhan, Yan-Ping; Chen, Shi-Biao

    2016-10-01

    To study the effect of dexmedetomidine priming on convulsion reaction induced by lidocaine.The New Zealand white rabbits were applied for the mechanism study of dexmedetomidine priming for preventing convulsion reaction induced by lidocaine. The influence of dexmedetomidine priming with different doses on the time for convulsion occurrence and the duration time of convulsion induced by lidocaine, as well as contents of excitatory amino acids (aspartate [Asp], glutamate [Glu]) and inhibitory amino acids (glycine [Gly], γ-aminobutyric acid [GABA]) in the brain tissue were investigated.With 3 and 5 μg/kg dexmedetomidine priming, the occurrence times of convulsion were prolonged from 196 seconds to 349 and 414 seconds, respectively. With dexmedetomidine priming, the contents of excitatory amino acids (Asp, Glu) were much reduced at occurrence time of convulsion comparing with that without dexmedetomidine priming, while content of inhibitory amino acids Gly was much enhanced.The application of dexmedetomidine before local anesthetics can improve intoxication dose threshold of the lidocaine, delay occurrence of the convulsion, and helped for the recovery of convulsion induced by lidocaine. The positive effect of dexmedetomidine on preventing convulsion would owe to not only the inhibition of excitatory amino acids (Asp, Glu), but also the promotion of inhibitory amino acids Gly secretion.

  15. Effect of dexmedetomidine priming on convulsion reaction induced by lidocaine

    PubMed Central

    Wang, Xi-Feng; Luo, Xiao-Ling; Liu, Wei-Cheng; Hou, Ben-Chao; Huang, Jian; Zhan, Yan-Ping; Chen, Shi-Biao

    2016-01-01

    Abstract To study the effect of dexmedetomidine priming on convulsion reaction induced by lidocaine. The New Zealand white rabbits were applied for the mechanism study of dexmedetomidine priming for preventing convulsion reaction induced by lidocaine. The influence of dexmedetomidine priming with different doses on the time for convulsion occurrence and the duration time of convulsion induced by lidocaine, as well as contents of excitatory amino acids (aspartate [Asp], glutamate [Glu]) and inhibitory amino acids (glycine [Gly], γ-aminobutyric acid [GABA]) in the brain tissue were investigated. With 3 and 5 μg/kg dexmedetomidine priming, the occurrence times of convulsion were prolonged from 196 seconds to 349 and 414 seconds, respectively. With dexmedetomidine priming, the contents of excitatory amino acids (Asp, Glu) were much reduced at occurrence time of convulsion comparing with that without dexmedetomidine priming, while content of inhibitory amino acids Gly was much enhanced. The application of dexmedetomidine before local anesthetics can improve intoxication dose threshold of the lidocaine, delay occurrence of the convulsion, and helped for the recovery of convulsion induced by lidocaine. The positive effect of dexmedetomidine on preventing convulsion would owe to not only the inhibition of excitatory amino acids (Asp, Glu), but also the promotion of inhibitory amino acids Gly secretion. PMID:27787355

  16. Report of the Workshop on Light Particle-Induced Reactions

    NASA Astrophysics Data System (ADS)

    The study meeting on light particle (mass number = 3 - 11) induced reaction was held for three days from 5-7 Dec. 1991 at the Research Center for Nuclear Physics, Osaka University. This book records the reports based on the lectures presented at the meeting. In the new facility of the RCNP, the experiment on the nuclear reaction using 400 MeV polarized protons and 200 MeV polarized deuterons is about to begin. When the acceleration of polarized He-3 beam which is being developed becomes feasible, by combining it with the high resolution spectrometer GRAND RAIDEN, it is expected that the unique, high accuracy research using the polarized He-3 having intermediate energy (540 MeV) becomes possible. At this time, by focusing attention to what new physics is developed by the nuclear reaction induced by the composite particles having the intermediate energy of mass number 3 - 11, this study meeting was planned and held. As the result, 29 lectures collected were to cover wide fields, and active discussion was carried out.

  17. Production and decay of baryonic resonances in pion induced reactions

    NASA Astrophysics Data System (ADS)

    Przygoda, Witold

    2016-11-01

    Pion induced reactions give unique opportunities for an unambiguous description of baryonic resonances and their coupling channels. A systematic energy scan and high precision data, in conjunction with a partial wave analysis, allow for the study of the excitation function of the various contributions. A review of available world data unravels strong need for modern facilities delivering measurements with a pion beam. Recently, HADES collaboration collected data in pion-induced reactions on light (12C) and heavy (74W) nuclei at a beam momentum of 1.7 GeV/c dedicated to strangeness production. It was followed by a systematic scan at four different pion beam momenta (0.656, 0.69, 0.748 and 0.8 GeV/c) in π- - p reaction in order to tackle the role of N(1520) resonance in conjunction with the intermediate ρ production. First results on exclusive channels with one pion (π- p) and two pions (nπ+π-, pπ-π0) in the final state are discussed.

  18. Electrokinetic locomotion due to Reaction Induced Charge Auto-Electrophoresis

    NASA Astrophysics Data System (ADS)

    Moran, Jeffrey; Posner, Jonathan

    2010-11-01

    Synthetic nanomotors, like their biological counterparts, propel themselves through aqueous solutions by harvesting chemical energy from their local environment and converting it to mechanical energy. We study bimetallic rod-shaped particles which move autonomously by catalytically decomposing hydrogen peroxide to oxygen and water. We present a scaling analysis and computational simulations that describe the locomotion of bimetallic rod-shaped motors in hydrogen peroxide solutions due to reaction-induced charge auto-electrophoresis. The model shows that the locomotion results from electrical body forces in the surrounding fluid, which are generated by a coupling of an asymmetric dipolar charge density distribution and the electric field it generates. The simulations make the predictions, in agreement with experiment, that the rods' velocity depends linearly on both the surface charge and reaction rate.

  19. Collective effects in deuteron induced reactions of aluminum

    NASA Astrophysics Data System (ADS)

    Canbula, Bora

    2017-01-01

    Cross sections of 27 Al (d,x)22 Na , 27 Al (d,x)24 Na , and 27 Al (d,x)27 Mg reactions are calculated by using TALYS 1.6 computer code with different nuclear level density models, which are composite Gilbert-Cameron model, back-shifted Fermi gas model, generalized superfluid model, and recently proposed collective semi-classical Fermi gas model in the energy range of 3-180 MeV. The results are compared with the experimental data taken from EXFOR library. In these deuteron induced reactions, collective effects are investigated by means of nuclear level density models. Collective semi-classical Fermi gas model including the collective effects via the level density parameter represents the best agreement with the experimental data compared to the other level density models, especially in the low deuteron bombarding energies where the collective effects dominate.

  20. Establishing a theory for deuteron induced surrogate reactions

    SciTech Connect

    Potel, G.; Nunes, F. M.; Thompson, I. J.

    2015-09-18

    Background: Deuteron-induced reactions serve as surrogates for neutron capture into compound states. Although these reactions are of great applicability, no theoretical efforts have been invested in this direction over the last decade. Purpose: The goal of this work is to establish on firm grounds a theory for deuteron-induced neutron-capture reactions. This includes formulating elastic and inelastic breakup in a consistent manner. Method: We describe this process both in post- and prior-form distorted wave Born approximation following previous works and discuss the differences in the formulation. While the convergence issues arising in the post formulation can be overcome in the prior formulation, in this case one still needs to take into account additional terms due to nonorthogonality. Results: We apply our method to the Nb93(d,p)X at Ed=15 and 25 MeV and are able to obtain a good description of the data. We then look at the various partial wave contributions, as well as elastic versus inelastic contributions. We also connect our formulation with transfer to neutron bound states.Conclusions: Our calculations demonstrate that the nonorthogonality term arising in the prior formulation is significant and is at the heart of the long-standing controversy between the post and the prior formulations of the theory. We also show that the cross sections for these reactions are angular-momentum dependent and therefore the commonly used Weisskopf limit is inadequate. We finally make important predictions for the relative contributions of elastic breakup and nonelastic breakup and call for elastic-breakup measurements to further constrain our model.

  1. Establishing a theory for deuteron induced surrogate reactions

    DOE PAGES

    Potel, G.; Nunes, F. M.; Thompson, I. J.

    2015-09-18

    Background: Deuteron-induced reactions serve as surrogates for neutron capture into compound states. Although these reactions are of great applicability, no theoretical efforts have been invested in this direction over the last decade. Purpose: The goal of this work is to establish on firm grounds a theory for deuteron-induced neutron-capture reactions. This includes formulating elastic and inelastic breakup in a consistent manner. Method: We describe this process both in post- and prior-form distorted wave Born approximation following previous works and discuss the differences in the formulation. While the convergence issues arising in the post formulation can be overcome in the priormore » formulation, in this case one still needs to take into account additional terms due to nonorthogonality. Results: We apply our method to the Nb93(d,p)X at Ed=15 and 25 MeV and are able to obtain a good description of the data. We then look at the various partial wave contributions, as well as elastic versus inelastic contributions. We also connect our formulation with transfer to neutron bound states.Conclusions: Our calculations demonstrate that the nonorthogonality term arising in the prior formulation is significant and is at the heart of the long-standing controversy between the post and the prior formulations of the theory. We also show that the cross sections for these reactions are angular-momentum dependent and therefore the commonly used Weisskopf limit is inadequate. We finally make important predictions for the relative contributions of elastic breakup and nonelastic breakup and call for elastic-breakup measurements to further constrain our model.« less

  2. Spin Modes, Neutrino-Induced Reactions and Nucleosynthesis in Stars

    SciTech Connect

    Suzuki, Toshio; Otsuka, Takaharu; Honma, Michio; Higashiyama, Koji

    2008-11-11

    Recent advances in shell model calculations of spin modes in nuclei with the use of new shell model Hamiltonians are discussed. Important roles of tensor interaction in shell evolutions toward drip-lines are pointed out. Electromagnetic transitions in exotic carbon isotopes are investigated. Anomalous supressions of transition strengths in the isotopes are found to be rather well explained. Neutrino-induced reactions on {sup 56}Fe and {sup 56}Ni are studied, and implications on production yields of heavy elements in stars are discussed.

  3. The algebraic cluster model: Structure of 16O

    NASA Astrophysics Data System (ADS)

    Bijker, R.; Iachello, F.

    2017-01-01

    We discuss an algebraic treatment of four-body clusters which includes both continuous and discrete symmetries. In particular, tetrahedral configurations with Td symmetry are analyzed with respect to the energy spectrum, transition form factors and B (EL) values. It is concluded that the low-lying spectrum of 16O can be described by four α particles at the vertices of a regular tetrahedron, not as a rigid structure but rather a more floppy structure with relatively large rotation-vibration interactions and Coriolis forces.

  4. Excitation functions for production of heavy actinides from interactions of /sup 16/O with /sup 249/Cf

    SciTech Connect

    Chasteler, R.M.; Henderson, R.A.; Lee, D.; Gregorich, K.E.; Nurmia, M.J.; Welch, R.B.; Hoffman, D.C.

    1987-11-01

    Excitation functions have been measured for the production of isotopes of Bk through Fm in bombardments of /sup 249/Cf with 90- to 150-MeV /sup 16/O ions. A comparison of the maxima of the mass-yield curves measured in this experiment with those for the reactions of /sup 18/O ions with /sup 249/Cf shows different shifts from those that have been measured for reactions of the /sup 16,18/O and /sup 20,22/Ne ion pairs with /sup 248/Cm. However, the shifts appear similar to those recently measured for reactions of these ion pairs with /sup 254/Es.

  5. Multi-strangeness production in hadron induced reactions

    NASA Astrophysics Data System (ADS)

    Gaitanos, T.; Moustakidis, Ch.; Lalazissis, G. A.; Lenske, H.

    2016-10-01

    We discuss in detail the formation and propagation of multi-strangeness particles in reactions induced by hadron beams relevant for the forthcoming experiments at FAIR. We focus the discussion on the production of the decuplet-particle Ω and study for the first time the production and propagation mechanism of this heavy hyperon inside hadronic environments. The transport calculations show the possibility of Ω-production in the forthcoming P ‾ANDA-experiment, which can be achieved with measurable probabilities using high-energy secondary Ξ-beams. We predict cross sections for Ω-production. The theoretical results are important in understanding the hyperon-nucleon and, in particular, the hyperon-hyperon interactions also in the high-strangeness sector. We emphasize the importance of our studies for the research plans at FAIR.

  6. Laser induced sonofusion: A new road toward thermonuclear reactions

    NASA Astrophysics Data System (ADS)

    Sadighi-Bonabi, Rasoul; Gheshlaghi, Maryam

    2016-03-01

    The Possibility of the laser assisted sonofusion is studied via single bubble sonoluminescence (SBSL) in Deuterated acetone (C3D6O) using quasi-adiabatic and hydro-chemical simulations at the ambient temperatures of 0 and -28.5 °C. The interior temperature of the produced bubbles in Deuterated acetone is 1.6 × 106 K in hydro-chemical model and it is reached up to 1.9 × 106 K in the laser induced SBSL bubbles. Under these circumstances, temperature up to 107 K can be produced in the center of the bubble in which the thermonuclear D-D fusion reactions are promising under the controlled conditions.

  7. A Transport Model for Nuclear Reactions Induced by Radioactive Beams

    SciTech Connect

    Li Baoan; Chen Liewen; Das, Champak B.; Das Gupta, Subal; Gale, Charles; Ko, C.M.; Yong, G.-C.; Zuo Wei

    2005-10-14

    Major ingredients of an isospin and momentum dependent transport model for nuclear reactions induced by radioactive beams are outlined. Within the IBUU04 version of this model we study several experimental probes of the equation of state of neutron-rich matter, especially the density dependence of the nuclear symmetry energy. Comparing with the recent experimental data from NSCL/MSU on isospin diffusion, we found a nuclear symmetry energy of Esym({rho}) {approx_equal} 31.6({rho}/{rho}0)1.05 at subnormal densities. Predictions on several observables sensitive to the density dependence of the symmetry energy at supranormal densities accessible at GSI and the planned Rare Isotope Accelerator (RIA) are also made.

  8. UV-induced reaction kinetics of dilinoleoylphosphatidylethanolamine monolayers.

    PubMed Central

    Viitala, T; Peltonen, J

    1999-01-01

    The UV-induced reactivity of dilinoleoylphosphatidylethanolamine (DLiPE) Langmuir and Langmuir-Blodgett films has been studied by in situ measurements of the changes in the mean molecular area, UV-vis and Fourier transform infrared spectroscopy, and atomic force microscopy (AFM). Optimum orientation and packing density of the DLiPE molecules in the monolayer were achieved by adding uranyl acetate to the subphase. A first-order reaction kinetic model was successfully fitted to the experimental reaction kinetics data obtained at a surface pressure of 30 mN/m. Topographical studies of LB films by AFM were performed on bilayer structures as a function of subphase composition and UV irradiation time. The orientational effect of the uranyl ions on the monolayer molecules was observed as an enhanced homogeneity of the freshly prepared monomeric LB films. However, the long-term stability of these films proved to be bad; clear reorganization and loss of a true monolayer structure were evidenced by the AFM images. This instability was inhibited for the UV-irradiated films, indicating that the UV irradiation gave rise to a cross-linked structure. PMID:10233096

  9. Expanded cumuli induce acrosome reaction in boar sperm.

    PubMed

    Mattioli, M; Lucidi, P; Barboni, B

    1998-12-01

    The authors investigated acrosomal changes occurring in boar sperm that interact with the expanded cumulus matrix surrounding ovulated pig oocytes. Samples of washed boar sperm obtained from six donors were incubated for 4 hr under capacitating conditions and exposed either to solubilized zonae pellucidae (ZP) or solubilized expanded pig cumuli (SEC) obtained from IVM oocytes. Alternatively, hyaluronic acid, laminin, or fibronectin, components of the extracellular matrix (ECM) were added to capacitated sperm. Acrosomal integrity was evaluated 1 hr later by using FITC-PSA staining. Solubilized cumuli induced acrosome reaction (AR) in a dose-dependent manner with a saturating effect exerted at 2.5 SEC/50 microl. Both 500 nM fibronectin and 500 nM laminin stimulated acrosomal exocytosis, the latter being more effective and inducing saturating levels of AR. By contrast, hyaluronic acid did not affect acrosomal status. Preincubation with anti-laminin antibodies completely prevented the inducing activity of SEC without affecting the activity of solubilized ZP. Consistent with these data, the integrin VLA-6, a receptor with high affinity for laminin, was detected by immunoblotting on the plasma membrane of capacitated boar spermatozoa. In addition, its immunoneutralization, obtained with the preincubation of capacitated sperm with the antibody raised against the alpha chain of VLA-6 integrin, prevented AR upon exposure to laminin or SEC (10.7+/-3.2 and 10.2+/-1.0% respectively), while the samples retained their responsiveness to ZP (29.6+/-1.2%). The results demonstrate that the interaction between laminin, entrapped in the expanded cumuli, and specific integrins present on the sperm membrane can initiate AR, thus taking part in the process of sperm-egg recognition.

  10. Search for 28Si cluster states through the 12C+16O radiative capture

    NASA Astrophysics Data System (ADS)

    Courtin, S.; Goasduff, A.; Haas, F.; Lebhertz, D.; Jenkins, D. G.; Hutcheon, D. A.; Davis, C.; Ruiz, C.

    2013-03-01

    The 12C+16O resonant radiative capture reaction has been studied at 5 bombarding energies around the Coulomb barrier, between Elab = 15.4 and 21.4 MeV. These experiments have been performed at the TRIUMF laboratory (Vancouver, Canada) using the Dragon 0° spectrometer and the associated BGO array. The most remarkable result is the previously unobserved decay path through 28Si doorway states of energies around 12 MeV leading to the measurement of new capture cross-sections. The feeding of specific, deformed states in 28Si from the resonances is discussed, as well as the selective feeding of 1+ T=1 states around 11 MeV.

  11. Theory of photon and electron induced reactions. Final report, July 1, 1990--June 30, 1993

    SciTech Connect

    Onley, D.S.; Wright, L.E.

    1993-01-01

    Theoretical work is reported on the following topics: photo- and electroproduction of mesons by the ({gamma},{pi}{sup {minus}}p) reactions on {sup 12}C and {sup 16}O; Coulomb distortion effects on (e,e{prime}{gamma}) and on inclusive (e,e{prime}) and exclusive (e,e{prime}p) scattering in the quasi-elastic region for {sup 40}Ca, {sup 208}Pb, and {sup 238}U; relativistic structure calculations in which the basic lagrangian is an extension of the {sigma}{endash}{omega} model in which the nucleons are coupled to five fields ({sigma}, {omega}, {rho}, {pi}, the electromagnetic field) and tensor coupling to the vector mesons {rho} and {omega} is also considered; and an investigation of the interaction {gamma} + p {yields} K{sup +} + {Lambda}{sup 0} in a simple quark model that supplies the coupling constants and form factors associated with each vertex in the Feynman diagrams. 19 figs., 51 refs.

  12. [Reaction mechanism studies of heavy ion induced nuclear reactions]. [Dept. of Chemistry and Biochemistry, Univ. of Maryland, College Park, Maryland

    SciTech Connect

    Mignerey, A.C.

    1993-02-01

    Completed work is summarized on the topics of excitation energy division in deep-inelastic reactions and the onset of multifragmentation in La-induced reactions at E/A = 45 MeV. Magnetic fields are being calculated for the PHOBOS detector system, a two-arm multiparticle spectrometer for studying low-transverse-momentum particles produced at the Relativistic Heavy Ion Collider. The Maryland Forward Array is being developed for detection of the reaction products from very peripheral collisions; it consists of two individual units of detectors: the annular silicon detector in front and the plastic phoswich detector at back.

  13. Mechanisms of laser induced reactions in opaque heterogeneous environments

    NASA Astrophysics Data System (ADS)

    Wilkinson, F.

    1993-11-01

    The technique of laser flash photolysis has been applied to both heterogeneous and homogeneous samples in order to increase understanding of the mechanisms of laser induced reactions at surfaces. Nanosecond diffuse reflectance laser flash photolysis has been used to study triplet state absorption and fluorescence emission of monomers and dimers of acridine orange and other dyes which are shown to aggregate when adsorbed on microcrystalline cellulose and on other surfaces. The properties of excited states within dyed fabrics have been evaluated in several cases. The mechanism of the yellowing of thermomechanical paper pulp has also been investigated and transients studied on nanosecond timescales for the first time. Triplet-triplet energy transfer from benzophenone to oxazine dyes, from eosin to anthracene, and from anthracene to azomethine dyes has been studied on both cellulose and silica surfaces. This work demonstrates the occurrence of energy transfer by static and dynamic mechanisms depending on both the nature of the surface and the adsorbed species. The first picosecond studies exciting directly into the charge transfer absorption bands of aromatic hydrocarbon/oxygen complexes formed in the presence of high pressures of oxygen have been carried out to demonstrate the role of charge-transfer interactions in determining the singlet oxygen formation efficiencies during quenching of electronically excited states by molecular oxygen. Nanosecond laser excitation of a series of naphthalene and anthracene derivatives in the presence and absence of oxygen has clearly demonstrated for the first time the importance of charge transfer interactions in determining oxygen quenching constants and singlet oxygen formation efficiencies.

  14. Persistent Skin Reactions and Aluminium Hypersensitivity Induced by Childhood Vaccines.

    PubMed

    Salik, Elaha; Løvik, Ida; Andersen, Klaus E; Bygum, Anette

    2016-11-02

    There is increasing awareness of reactions to vaccination that include persistent skin reactions. We present here a retrospective investigation of long-lasting skin reactions and aluminium hypersensitivity in children, based on medical records and questionnaires sent to the parents. In the 10-year period 2003 to 2013 we identified 47 children with persistent skin reactions caused by childhood vaccinations. Most patients had a typical presentation of persisting pruritic subcutaneous nodules. Five children had a complex diagnostic process involving paediatricians, orthopaedics and plastic surgeons. Two patients had skin biopsies performed from their skin lesions, and 2 patients had the nodules surgically removed. Forty-two children had a patch-test performed with 2% aluminium chloride hexahydrate in petrolatum and 39 of them (92%) had a positive reaction. The persistent skin reactions were treated with potent topical corticosteroids and disappeared slowly. Although we advised families to continue vaccination of their children, one-third of parents omitted or postponed further vaccinations.

  15. Identification of MHC Haplotypes Associated with Drug-induced Hypersensitivity Reactions in Cynomolgus Monkeys.

    PubMed

    Wu, Hong; Whritenour, Jessica; Sanford, Jonathan C; Houle, Christopher; Adkins, Karissa K

    2017-01-01

    Drug-induced hypersensitivity reactions can significantly impact drug development and use. Studies to understand risk factors for drug-induced hypersensitivity reactions have identified genetic association with specific human leukocyte antigen (HLA) alleles. Interestingly, drug-induced hypersensitivity reactions can occur in nonhuman primates; however, association between drug-induced hypersensitivity reactions and major histocompatibility complex (MHC) alleles has not been described. In this study, tissue samples were collected from 62 cynomolgus monkeys from preclinical studies in which 9 animals had evidence of drug-induced hypersensitivity reactions. Microsatellite analysis was used to determine MHC haplotypes for each animal. A total of 7 haplotypes and recombinant MHC haplotypes were observed, with distribution frequency comparable to known MHC I allele frequency in cynomolgus monkeys. Genetic association analysis identified alleles from the M3 haplotype of the MHC I B region (B*011:01, B*075:01, B*079:01, B*070:02, B*098:05, and B*165:01) to be significantly associated (χ(2) test for trend, p < 0.05) with occurrence of drug-induced hypersensitivity reactions. Sequence similarity from alignment of alleles in the M3 haplotype B region and HLA alleles associated with drug-induced hypersensitivity reactions in humans was 86% to 93%. These data demonstrate that MHC alleles in cynomolgus monkeys are associated with drug-induced hypersensitivity reactions, similar to HLA alleles in humans.

  16. [Adverse cutaneous reactions induced by exposure to woods].

    PubMed

    Chomiczewska-Skóra, Dorota

    2013-01-01

    Various adverse cutaneous reactions may occur as a result of exposure to wood dust or solid woods. These include allergic contact dermatitis, irritant contact dermatitis and, more rarely, contact urticaria, photoallergic and phototoxic reactions. Also cases of erythema multiforme-like reactions have been reported. Contact dermatitis, both allergic and irritant, is most frequently provoked by exotic woods, e.g. wood of the Dalbergia spp., Machaerium scleroxylon or Tectona grandis. Cutaneous reactions are usually associated with manual or machine woodworking, in occupational setting or as a hobby. As a result of exposure to wood dust, airborne contact dermatitis is often diagnosed. Cases of allergic contact dermatitis due to solid woods of finished articles as jewelry or musical instruments have also been reported. The aim of the paper is to present various adverse skin reactions related to exposure to woods, their causal factors and sources of exposure, based on the review of literature.

  17. Model-independent analysis of Airy structures in the {sup 16}O+{sup 12}C and {sup 16}O+{sup 16}O elastic scattering differential cross sections at 13-22 MeV/nucleon

    SciTech Connect

    Korda, V. Yu.; Molev, A. S.; Klepikov, V. F.; Korda, L. P.

    2009-02-15

    We present the results of the model-independent analysis of Airy structures in the {sup 16}O+{sup 12}C and {sup 16}O+{sup 16}O elastic scattering differential cross sections at 13-22 MeV/nucleon. The analysis has been performed with help of a procedure based on the application of the evolutionary algorithm, which enables us to extract the nuclear part of the scattering matrix S{sub N}(l) as a complex function of angular momentum directly from the scattering data. Contrary to the commonly used model approaches, our procedure gives the better fits and leads to the S{sub N}(l) representations defined by the moduli and the nuclear phases exhibiting smooth monotonic dependencies on l.

  18. Evaluation on thermal explosion induced by slightly exothermic interface reaction.

    PubMed

    Yu, Ma-Hong; Li, Yong-Fu; Sun, Jin-Hua; Hasegawa, Kazutoshi

    2004-09-10

    An asphalt-salt mixture (ASM), which once caused a fire and explosion in a reprocessing plant, was prepared by imitating the real bituminization process of waste on a lab scale to evaluate its actual thermal hazards. Heat flux reaction calorimeters were used to measure the release of heat for the simulated ASM at a constant heating rate and at a constant temperature, respectively. Experimental results show that the reaction in the ASM below about 250 degrees C is a slightly exothermic interface reaction between the asphalt and the salt particles contained in the asphalt, and that the heat release rate increases sharply above about 250 degrees C due to melting of the salt particles. The reaction rates were formulated on the basis of an assumed reaction model, and the kinetic parameters were determined. Using the model with the kinetic parameters, temperature changes with time and drum-radius axes for the ASM-filled drum were numerically simulated assuming a one-dimensional infinite cylinder system, where the drum was being cooled at an ambient temperature of 50 degrees C. The minimum filling temperature, at which the runaway reaction (MFTRR) can occur for the simulated ASM in the drum is about 194 degrees C. Furthermore, a very good linear correlation exists between this MFTRR and the initial radius of salt particles formed in the bituminization product. The critical filling temperature to the runaway reaction is about 162 degrees C for the asphalt-salt mixture, containing zero-size salt particles, filled in the same drum at an ambient temperature of 50 degrees C. Thus, the runaway reaction will never occur in the drum filled with the asphalt-salt mixture under the conditions of the filling temperature below 162 degrees C and a constant ambient temperature of 50 degrees C. As a consequence, the ASM explosion occurred in the reprocessing plant likely was due to a slightly exothermically reaction and self heating.

  19. Radiotherapy-induced skin reactions: assessment and management.

    PubMed

    Glover, Deborah; Harmer, Victoria

    Radiotherapy, the use of high-energy rays to either kill cancer cells or treat some benign tumours, is undoubtedly a positive intervention. However, as the primary mode of action in radiotherapy treatment is the killing of cells to prevent replication, other non-cancerous cells may be affected. For example, up to 85% of patients will experience some form of skin reaction, which will range from local erythema to moist desquamation. Such reactions are not only distressing and painful for the patient, if severe enough, they may warrant a halt in treatment. This article outlines the aims and nature of radiotherapy, and then discusses the aetiology of skin reactions, risk factors for reaction, and assessment tools. Management interventions will also be shown, with emphasis on silicone dressings.

  20. Studies of alpha-induced astrophysical reactions at CRIB

    SciTech Connect

    Yamaguchi, H.; Hashimoto, T.; Hayakawa, S.; Binh, D. N.; Kahl, D.; Kubono, S.

    2010-08-12

    CRIB (CNS Radioactive Ion Beam separator) is a low-energy RI beam separator at the Center for Nuclear Study (CNS) of the University of Tokyo. Using the RI beams at CRIB, many measurements on proton alpha resonance scatterings, ({alpha},p) reactions, and others were performed in recent years mainly for studying astrophysical reactions and exotic nuclear structure. Among them, the results on the {sup 7}Li+{alpha} resonance scatterings are presented.

  1. [DRUG INDUCED EXANTHEMA AND SEVERE CUTANEOUS DRUG REACTIONS].

    PubMed

    Bensaïd, Benoît; Valeyrie-Allanore, Laurence; Lebrun-Vignes, Bénédicte; Nicolas, Jean-François

    2015-09-01

    Cutaneous adverse drug reactions (CADR) are delayed hypersensivities. Their clinical presentation and severity are very diverse ranging from the frequent and benign exanthemas to the rare but severe CADR involving deep organs in the case of drug reaction with eosinophilia and systemic symptoms (DRESS) or leading to skin bulla and epidermal detachment in toxic epidermal necrolysis. The main differential diagnoses are infections, especially viral ones, which could give clinical symptoms identical to those occurring in CADR.

  2. Existence of an 16O-rich gaseous reservoir in the solar nebula.

    PubMed

    Krot, Alexander N; McKeegan, Kevin D; Leshin, Laurie A; MacPherson, Glenn J; Scott, Edward R D

    2002-02-08

    Carbonaceous chondrite condensate olivine grains from two distinct petrographic settings, calcium-aluminum-rich inclusion (CAI) accretionary rims and amoeboid olivine aggregates (AOAs), are oxygen-16 (16O) enriched at the level previously observed inside CAIs. This requires that the gas in the nebular region where these grains condensed was 16O-rich. This contrasts with an 16O-poor gas present during the formation of chondrules, suggesting that CAIs and AOAs formed in a spatially restricted region of the solar nebula containing 16O-rich gas. The 16O-rich gas composition may have resulted either from mass-independent isotopic chemistry or from evaporation of regions with enhanced dust/gas ratios, possibly in an X-wind environment near the young Sun.

  3. Perspective: Vibrational-induced steric effects in bimolecular reactions

    NASA Astrophysics Data System (ADS)

    Liu, Kopin

    2015-02-01

    The concept of preferred collision geometry in a bimolecular reaction is at the heart of reaction dynamics. Exemplified by a series of crossed molecular beam studies on the reactions of a C-H stretch-excited CHD3(v1 = 1) with F, Cl, and O(3P) atoms, two types of steric control of chemical reactivity will be highlighted. A passive control is governed in a reaction with strong anisotropic entry valley that can significantly steer the incoming trajectories. This disorientation effect is illustrated by the F and O(3P) + CHD3(v1 = 1) reactions. In the former case, the long-range anisotropic interaction acts like an optical "negative" lens by deflecting the trajectories away from the favored transition-state geometry, and thus inhibiting the bond rupture of the stretch-excited CHD3. On the contrary, the interaction between O(3P) and CHD3(v1 = 1) behaves as a "positive" lens by funneling the large impact-parameter collisions into the cone of acceptance, and thereby enhances the reactivity. As for reactions with relatively weak anisotropic interactions in the entry valley, an active control can be performed by exploiting the polarization property of the infrared excitation laser to polarize the reactants in space, as demonstrated in the reaction of Cl with a pre-aligned CHD3(v1 = 1) reactant. A simpler case, the end-on versus side-on collisions, will be elucidated for demonstrating a means to disentangle the impact-parameter averaging. A few general remarks about some closely related issues, such as mode-, bond-selectivity, and Polanyi's rules, are made.

  4. Perspective: Vibrational-induced steric effects in bimolecular reactions

    SciTech Connect

    Liu, Kopin

    2015-02-28

    The concept of preferred collision geometry in a bimolecular reaction is at the heart of reaction dynamics. Exemplified by a series of crossed molecular beam studies on the reactions of a C–H stretch-excited CHD{sub 3}(v{sub 1} = 1) with F, Cl, and O({sup 3}P) atoms, two types of steric control of chemical reactivity will be highlighted. A passive control is governed in a reaction with strong anisotropic entry valley that can significantly steer the incoming trajectories. This disorientation effect is illustrated by the F and O({sup 3}P) + CHD{sub 3}(v{sub 1} = 1) reactions. In the former case, the long-range anisotropic interaction acts like an optical “negative” lens by deflecting the trajectories away from the favored transition-state geometry, and thus inhibiting the bond rupture of the stretch-excited CHD{sub 3}. On the contrary, the interaction between O({sup 3}P) and CHD{sub 3}(v{sub 1} = 1) behaves as a “positive” lens by funneling the large impact-parameter collisions into the cone of acceptance, and thereby enhances the reactivity. As for reactions with relatively weak anisotropic interactions in the entry valley, an active control can be performed by exploiting the polarization property of the infrared excitation laser to polarize the reactants in space, as demonstrated in the reaction of Cl with a pre-aligned CHD{sub 3}(v{sub 1} = 1) reactant. A simpler case, the end-on versus side-on collisions, will be elucidated for demonstrating a means to disentangle the impact-parameter averaging. A few general remarks about some closely related issues, such as mode-, bond-selectivity, and Polanyi’s rules, are made.

  5. Direct measurements of astrophysically important α-induced reactions

    NASA Astrophysics Data System (ADS)

    Avila, Melina

    2016-03-01

    Understanding stellar evolution is one of the primary objectives of nuclear astrophysics. Reaction rates involving α-particles are often key nuclear physics inputs in stellar models. For instance, there are numerous (α , p) reactions fundamental for the understanding of X-ray bursts and the production of 44Ti in core-collapse supernovae. Furthermore, some (α , n) reactions are considered as one of the main neutron sources in the s-process. However, direct measurements of these reactions at relevant astrophysical energies are experimentally challenging because of their small cross section and intensity limitation of radioactive beams. The active target system MUSIC offers a unique opportunity to study (α , p) and (α , n) reactions because its segmented anode allows the investigation of a large energy range in the excitation function with a single measurement. Recent results on the direct measurement of (α , n) and (α , p) measurements in the MUSIC detector will be discussed. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Contract Number DE-AC02-06CH11357. This research used resources of ANL's ATLAS facility, which is a DOE Office of Science User.

  6. Population of Nuclei Via 7Li-Induced Binary Reactions

    SciTech Connect

    Clark, Rodney M.; Phair, Larry W.; Descovich, M.; Cromaz, Mario; Deleplanque, M.A.; Fall on, Paul; Lee, I-Yang; Macchiavelli, A.O.; McMahan, Margaret A.; Moretto, Luciano G.; Rodriguez-Vieitez, E.; Sinha,Shrabani; Stephens, Frank S.; Ward, David; Wiedeking, Mathis

    2005-08-08

    The authors have investigated the population of nuclei formed in binary reactions involving {sup 7}Li beams on targets of {sup 160}Gd and {sup 184}W. The {sup 7}Li + {sup 184}W data were taken in the first experiment using the LIBERACE Ge-array in combination with the STARS Si {Delta}E-E telescope system at the 88-Inch Cyclotron of the Lawrence Berkeley National Laboratory. By using the Wilczynski binary transfer model, in combination with a standard evaporation model, they are able to reproduce the experimental results. This is a useful method for predicting the population of neutron-rich heavy nuclei formed in binary reactions involving beams of weakly bound nuclei formed in binary reactions involving beams of weakly bound nuclei and will be of use in future spectroscopic studies.

  7. (α, γ) reaction induced background events for rare event experiments

    NASA Astrophysics Data System (ADS)

    Tiwari, Ashok; Zhang, Chao; Mei, Dongming

    2016-09-01

    We report an observation of (α, γ) reaction at the Soudan mine. With a 12-Liter scintillation neutron detector at Soudan mine for about 5 years of data taking, we have observed (α, γ) reaction, which can generate potential background events for dark matter and neutrinoless double-beta decay experiments. We have simulated the alpha flux from radon decay using the measured radon concentration in Soudan mine. The convolution of the alpha flux and the cross-section of (α, γ) allows us to determine the rate of high energy gamma from (α, γ) reaction. This rate is compared to the measured event rate. We demonstrate that the modulation of (α, γ) event rate has similar pattern as the radon modulation observed independently in Soudan mine. This work is supported by NSF in part by the NSF PHY-0758120, DOE Grant DE-FG02-10ER46709, and the State of South Dakota.

  8. Physiological Environment Induces Quick Response – Slow Exhaustion Reactions

    PubMed Central

    Hiroi, Noriko; Lu, James; Iba, Keisuke; Tabira, Akito; Yamashita, Shuji; Okada, Yasunori; Flamm, Christoph; Oka, Kotaro; Köhler, Gottfried; Funahashi, Akira

    2011-01-01

    In vivo environments are highly crowded and inhomogeneous, which may affect reaction processes in cells. In this study we examined the effects of intracellular crowding and an inhomogeneity on the behavior of in vivo reactions by calculating the spectral dimension (ds), which can be translated into the reaction rate function. We compared estimates of anomaly parameters obtained from fluorescence correlation spectroscopy (FCS) data with fractal dimensions derived from transmission electron microscopy (TEM) image analysis. FCS analysis indicated that the anomalous property was linked to physiological structure. Subsequent TEM analysis provided an in vivo illustration; soluble molecules likely percolate between intracellular clusters, which are constructed in a self-organizing manner. We estimated a cytoplasmic spectral dimension ds to be 1.39 ± 0.084. This result suggests that in vivo reactions initially run faster than the same reactions in a homogeneous space; this conclusion is consistent with the anomalous character indicated by FCS analysis. We further showed that these results were compatible with our Monte-Carlo simulation in which the anomalous behavior of mobile molecules correlates with the intracellular environment, leading to description as a percolation cluster, as demonstrated using TEM analysis. We confirmed by the simulation that the above-mentioned in vivo like properties are different from those of homogeneously concentrated environments. Additionally, simulation results indicated that crowding level of an environment might affect diffusion rate of reactant. Such knowledge of the spatial information enables us to construct realistic models for in vivo diffusion and reaction systems. PMID:21960972

  9. Analysis and theoretical modeling of the 18O enriched carbon dioxide spectrum by CRDS near 1.35 μm: (I) 16O12C18O, 16O12C17O, 12C16O2 and 13C16O2

    NASA Astrophysics Data System (ADS)

    Kassi, S.; Karlovets, E. V.; Tashkun, S. A.; Perevalov, V. I.; Campargue, A.

    2017-01-01

    The room temperature absorption spectrum of 18O enriched carbon dioxide has been recorded by very high-sensitivity Cavity Ring Down spectroscopy between 6977 and 7918 cm-1 (1.43-1.26 μm). The achieved sensitivity (noise equivalent absorption αmin 8×10-11 cm-1) has allowed for the detection of more than 8600 lines belonging to 166 bands of eleven carbon dioxide isotopologues. Line intensities of the weakest observed transitions are on the order of 2×10-30 cm/molecule. In this first part, we present the results relative to the 16O12C18O, 16O12C17O, 12C16O2 and 13C16O2 isotopologues. Their absorption lines were rovibrationally assigned on the basis of the predictions of their respective effective Hamiltonian model. Overall 5476 lines were measured and assigned to 93 bands. Forty nine of them, all belonging to 16O12C18O and 16O12C17O, are reported for the first time. The studied spectral region is formed by ΔP=10-12 series of transitions, where P=2V1+V2+3V3 is the polyad number (Vi are vibrational quantum numbers). The spectroscopic parameters of 58 bands of 16O12C18O and 16O12C17O were determined from a fit of the measured line positions. An inter- and an intrapolyad resonance perturbation were identified and analyzed in the 16O12C18O spectrum. The comparison with the line positions and line intensities included in the AMES line list is discussed. Global fits of the line intensities were performed in order to (i) improve the ΔP=10 and 11 sets of the effective dipole moment parameters of 16O12C18O and the ΔP=11 set of parameters of 16O12C17O and (ii) derive for the first time the ΔP=10 and 12 parameters of 16O12C17O and 16O12C18O, respectively.

  10. Low-energy deuteron-induced reactions on 93Nb

    NASA Astrophysics Data System (ADS)

    Avrigeanu, M.; Avrigeanu, V.; Bém, P.; Fischer, U.; Honusek, M.; Koning, A. J.; Mrázek, J.; Šimečková, E.; Štefánik, M.; Závorka, L.

    2013-07-01

    The activation cross sections of (d,p), (d,2n), (d,2np+nd+t), (d,2nα), and (d,pα) reactions on 93Nb were measured in the energy range from 1 to 20 MeV using the stacked-foil technique. Then, within a simultaneous analysis of elastic scattering and reaction data, the available elastic-scattering data analysis was carried out in order to obtain the optical potential for reaction cross-section calculations. Particular attention was paid to the description of the breakup mechanism and direct reaction stripping and pick-up, followed by pre-equilibrium and compound-nucleus calculations. The measured cross sections as well as all available deuteron activation data of 93Nb were compared with results of local model calculations carried out using the codes fresco and stapre-h and both default and particular predictions of the code talys-1.4 and tendl-2012-evaluated data.

  11. Pulmonary reactions caused by welding-induced decomposed trichloroethylene

    SciTech Connect

    Sjoegren, B.P.; Plato, N.; Alexandersson, R.; Eklund, A.; Falkenberg, C. )

    1991-01-01

    This is the report of a welder who performed argon-shielded electric arc welding in an atmosphere containing trichloroethylene. He developed immediate respiratory symptoms, pulmonary edema 12 hours after exposure, and recurring dyspnea ten days after exposure. These pulmonary reactions might be explained by inhalation of decomposition products of trichloroethylene such as dichloroacetyl chloride and phosgene.

  12. Unexpected death due to cefuroxime-induced disulfiram-like reaction

    PubMed Central

    Dong, Hongmei; Zhang, Ji; Ren, Liang; Liu, Qian; Zhu, Shaohua

    2013-01-01

    Cefuoxime, a second-generation cephalosporin, is used in the treatment of Gram-positive infections. Here, we report a case cefuroxime-induced disulfiram-like reaction which led to sudden death of the patient. PMID:24014919

  13. 12C(α,γ)16O cross sections at stellar energies

    NASA Astrophysics Data System (ADS)

    Ouellet, J. M. L.; Butler, M. N.; Evans, H. C.; Lee, H. W.; Leslie, J. R.; MacArthur, J. D.; McLatchie, W.; Mak, H.-B.; Skensved, P.; Whitton, J. L.; Zhao, X.; Alexander, T. K.

    1996-10-01

    The excitation function of the 12C(α,γ)16O reaction and the angular distribution of its γ rays were measured at nine center-of-mass energies ranging from E=1.37 to 2.98 MeV. These measurements allowed the separation of the E1 and E2 contributions and their extrapolation to the region of astrophysical interest. The analysis of all the available E1 cross sections with the K-matrix method and with a three-level R-matrix method yields a consistent prediction of 79+/-16 keV b for the E1 S factor at 300 keV. The E2 contribution at the same energy is 36+/-6 keV b from a cluster model analysis of the present data. The best estimate of the total S factor at 300 keV is 120 keV b, and it is unlikely that it will fall outside the range of 80-160 keV b.

  14. Modeled Neutron Induced Nuclear Reaction Cross Sections for Radiochemistry in the region of Iriduim and Gold

    SciTech Connect

    Hoffman, R D; Dietrich, F S; Kelley, K; Escher, J; Bauer, R; Mustafa, M

    2008-02-26

    We have developed a set of modeled nuclear reaction cross sections for use in radiochemical diagnostics. Systematics for the input parameters required by the Hauser-Feshbach statistical model were developed and used to calculate neutron induced nuclear reaction cross sections for targets ranging from osmium (Z = 76) to gold (Z = 79). Of particular interest are the cross sections on Ir and Au including reactions on isomeric targets.

  15. Modeling Proton- and Light Ion-Induced Reactions at Low Energies in the MARS15 Code

    SciTech Connect

    Rakhno, I. L.; Mokhov, N. V.; Gudima, K. K.

    2015-04-25

    An implementation of both ALICE code and TENDL evaluated nuclear data library in order to describe nuclear reactions induced by low-energy projectiles in the Monte Carlo code MARS15 is presented. Comparisons between results of modeling and experimental data on reaction cross sections and secondary particle distributions are shown.

  16. Population of Nuclei Via 7Li-Induced Binary Reactions

    SciTech Connect

    Clark, R M; Phair, L W; Descovich, M; Cromaz, M; Deleplanque, M A; Fallon, P; Lee, I Y; Macchiavelli, A O; McMahan, M A; Moretto, L G; Rodriguez-Vieitez, E; Sinha, S; Stephens, F S; Ward, D; Wiedeking, M; Bernstein, L A; Burke, J T; Church, J A

    2005-08-09

    The authors have investigated the population of nuclei formed in binary reactions involving {sup 7}Li beams on targets of {sup 160}Gd and {sup 184}W. The {sup 7}Li + {sup 184}W data were taken in the first experiment using the LIBERACE Ge-array in combination with the STARS Si {Delta}E-E telescope system at the 88-Inch Cyclotron of the Lawrence Berkeley National Laboratory. By using the Wilczynski binary transfer model, in combination with a standard evaporation model, they are able to reproduce the experimental results. This is a useful method for predicting the population of neutron-rich heavy nuclei formed in binary reactions involving beams of weakly bound nuclei and will be of use in future spectroscopic studies.

  17. Reaction-induced rheological weakening enables oceanic plate subduction

    NASA Astrophysics Data System (ADS)

    Hirauchi, Ken-Ichi; Fukushima, Kumi; Kido, Masanori; Muto, Jun; Okamoto, Atsushi

    2016-08-01

    Earth is the only terrestrial planet in our solar system where an oceanic plate subducts beneath an overriding plate. Although the initiation of plate subduction requires extremely weak boundaries between strong plates, the way in which oceanic mantle rheologically weakens remains unknown. Here we show that shear-enhanced hydration reactions contribute to the generation and maintenance of weak mantle shear zones at mid-lithospheric depths. High-pressure friction experiments on peridotite gouge reveal that in the presence of hydrothermal water, increasing strain and reactions lead to an order-of-magnitude reduction in strength. The rate of deformation is controlled by pressure-solution-accommodated frictional sliding on weak hydrous phyllosilicate (talc), providing a mechanism for the `cutoff' of the high peak strength at the brittle-plastic transition. Our findings suggest that infiltration of seawater into transform faults with long lengths and low slip rates is an important controlling factor on the initiation of plate tectonics on terrestrial planets.

  18. Reaction-induced rheological weakening enables oceanic plate subduction.

    PubMed

    Hirauchi, Ken-Ichi; Fukushima, Kumi; Kido, Masanori; Muto, Jun; Okamoto, Atsushi

    2016-08-26

    Earth is the only terrestrial planet in our solar system where an oceanic plate subducts beneath an overriding plate. Although the initiation of plate subduction requires extremely weak boundaries between strong plates, the way in which oceanic mantle rheologically weakens remains unknown. Here we show that shear-enhanced hydration reactions contribute to the generation and maintenance of weak mantle shear zones at mid-lithospheric depths. High-pressure friction experiments on peridotite gouge reveal that in the presence of hydrothermal water, increasing strain and reactions lead to an order-of-magnitude reduction in strength. The rate of deformation is controlled by pressure-solution-accommodated frictional sliding on weak hydrous phyllosilicate (talc), providing a mechanism for the 'cutoff' of the high peak strength at the brittle-plastic transition. Our findings suggest that infiltration of seawater into transform faults with long lengths and low slip rates is an important controlling factor on the initiation of plate tectonics on terrestrial planets.

  19. Multimodal Fission in Heavy-Ion Induced Reactions

    SciTech Connect

    Pokrovskiy, I. V.; Bogachev, A. A.; Iitkis, M. G.; Iitkis, J. M.; Kondratiev, N. A.; Kozulin, E. M.; Dorvaux, O.; Rowley, N.; Schmitt, Ch.; Stuttge, L.

    2006-08-14

    Mass, energy and folding angle distributions of the fission fragments as well as multiplicities of neutron and gamma-quanta emissions accompanying the fission process were measured for fission of 226Th, 227Pa and 234Pu compound nuclei produced in reactions with 18O and 26Mg projectiles over a wide energy range. Data were analyzed with respect to the presence of fission modes. Asymmetric fission was observed even at very high initial excitation for all the measured systems. The so-called fission mode S1 (caused by the proton shell Z{approx}50 and neutron shell N{approx}82 in heavy fragment) was found to be dominant in asymmetric fission of 234Pu. Reactions with not full linear momentum transfer were observed in the folding spectra for all the measured systems.

  20. Robotic reactions: delay-induced patterns in autonomous vehicle systems.

    PubMed

    Orosz, Gábor; Moehlis, Jeff; Bullo, Francesco

    2010-02-01

    Fundamental design principles are presented for vehicle systems governed by autonomous cruise control devices. By analyzing the corresponding delay differential equations, it is shown that for any car-following model short-wavelength oscillations can appear due to robotic reaction times, and that there are tradeoffs between the time delay and the control gains. The analytical findings are demonstrated on an optimal velocity model using numerical continuation and numerical simulation.

  1. Shock-Induced Chemical Reactions in Condensed Matter.

    DTIC Science & Technology

    1982-08-01

    Technical, 4/1/78 - 6/30/82 Matter 6. PERFORMING ORG. REPORT NUMBER 7. AUTHOR(s) S. CONTRACT OR GRANT NUMUER(e) George E. Duvall, Principal Investigator...CHEMICAL REACTIONS IN CONDENSED MATTER George E. Duvall, Principal Investigator Stephen A. Sheffield* Kendal M. OgilvieT 4 C. Robert Wilson Paul...Temperture," in Sixth Symposium (International on Detonation (Office of Naval Research, Arlington, 1976), ACR-Z21, p. 36. 24. G. Gamow , "Tentative

  2. Continuum effects in transfer reactions induced by heavy ions

    SciTech Connect

    Marta, H.D.; Donangelo, R.; Fernandez Niello, J.O.; Pacheco, A.J.

    2006-02-15

    In the usual treatment of transfer nuclear reactions, the continuum states of the transferred particle are neglected. Here we perform a semiclassical calculation that treats the continuum in an exact way. For comparison purposes, we perform a second calculation in which the continuum is completely disregarded. The results of these two calculations indicates that the influence of the continuum states may be very important in systems with weakly bound reactants.

  3. Relativity versus exchange currents in 16O(e ,e'p )

    NASA Astrophysics Data System (ADS)

    Grineviciute, J.; Halderson, Dean

    2016-07-01

    Background: The 16O(e ,e'p ) reaction in the quasielastic region has been studied in several experiments to determine spectroscopic factors, hence, the degree to which 16O looks like a closed shell. By varying the kinematics, experimentalists are able to extract response functions which comprise the cross section. However, analysis of the response functions separately produces very different spectroscopic factors. Two calculations led to different conclusions as to whether exchange currents can eliminate the discrepancies. Neither calculation considered relativistic corrections. Purpose: The purpose of the article is to investigate the disagreement as to whether exchange currents are the solution to obtaining consistent spectroscopic factors and to show that relativistic corrections have a much greater influence on providing this consistency. Methods: This calculation employs the recoil corrected continuum shell model, a model that uses a realistic interaction and produces nonspurious scattering states that are solutions to the coupled-channel problems. Pionic and pair contributions to the exchange currents were calculated as developed by Dubach et al. [Nucl. Phys. A 271, 279 (1976), 10.1016/0375-9474(76)90246-3]. Relativistic effects are included by use of the direct Pauli reduction. Results: Contributions of the exchange currents are shown to be insufficient to provide consistent spectroscopic factors. However, the inclusion of relativistic corrections produces spectroscopic factors from the different responses and cross sections which are very similar for both the p1 /2 and the p3 /2 states and both the (|q |,ω )=(460 MeV /c ,100 MeV ) and (|q |,ω )=(570 MeV /c ,172 MeV ) data. The influence of channel coupling is also shown to be significant. Tests of current conservation show that inclusion of the direct Pauli reduction produces small increases in its violation. Conclusions: Results are model dependent. Meson-exchange current contributions are not sufficient

  4. Diethyl pyrocarbonate reaction with the lactose repressor protein affects both inducer and DNA binding

    SciTech Connect

    Sams, C.F.; Matthews, K.S.

    1988-04-05

    Modification of the lactose repressor protein of Escherichia coli with diethyl pyrocarbonate (DPC) results in decreased inducer binding as well as operator and nonspecific DNA binding. Spectrophotometric measurements indicated a maximum of three histidines per subunit was modified, and quantitation of lysine residues with trinitrobenzenesulfonate revealed the modification of one lysine residue. The loss of DNA binding, both operator and nonspecific, was correlated with histidine modification; removal of the carbethoxy groups from the histidines by hydroxylamine was accompanied by significant recovery of DNA binding function. The presence of inducing sugars during the DPC reaction had no effect on histidine modification or the loss of DNA binding activity. In contrast, inducer binding was not recovered upon reversal of the histidine modification. However, the presence of inducer during reaction protected lysine from reaction and also prevented the decrease in inducer binding; these results indicate that reaction of the lysine residue(s) may correlate to the loss of sugar binding activity. Since no difference in incorporation of radiolabeled carbethoxy was observed following reaction with diethyl pyrocarbonate in the presence or absence of inducer, the reagent appears to function as a catalyst in the modification of the lysine. The formation of an amide bond between the affected lysine and a nearby carboxylic acid moiety provides a possible mechanism for the activity loss. Reaction of the isolated NH2-terminal domain resulted in loss of DNA binding with modification of the single histidine at position 29. Results from the modification of core domain paralleled observations with intact repressor.

  5. Systematic review of NSAID-induced adverse reactions in patients with rheumatoid arthritis in Japan.

    PubMed

    Tomita, Tetsuya; Ochi, Takahiro; Sugano, Kentaro; Uemura, Shinichi; Makuch, Robert W

    2003-06-01

    Abstract A systematic review of randomized controlled clinical trials of nonsteroidal antiinflammatory drugs (NSAIDs) in rheumatoid arthritis (RA) patients was conducted to evaluate the risk of NSAID-induced adverse reactions. Double-blind, randomized, controlled trials with 6-week treatments for RA patients were included in the study. The endpoints for the analysis included any adverse reactions, digestive adverse reactions, and upper gastrointestinal (GI) adverse reactions. A fixed-effect model was used for estimation of the risk. Time-to-event analysis of the incidence of adverse reactions was also conducted. A total of 28 trials was included for the analysis, and a total of 30 NSAIDs were used in the trials. The proportion of patients who experienced any adverse reaction was as follows: piroxicam 18.9% (3 trials), diclofenac 18.8% (4 trials), indomethacin 22.1% (14 trials), and aspirin 25.0% (4 trials). The proportion of patients who experienced digestive adverse reactions was as follows: piroxicam 10.2%, diclofenac 10.6%, indomethacin 13.1%, and aspirin 14.1%. Most withdrawals due to adverse reaction occurred during the first 3 weeks after administration of the NSAID. Although the risk of NSAID-induced adverse reaction was different from drug to drug, the risk of adverse reaction was clinically significant.

  6. Kinetics of Reactions of Monomeric Nitrosomethane Induced by Flash Photolysis.

    ERIC Educational Resources Information Center

    Kozubek, H.; And Others

    1984-01-01

    Describes an experiment in which the kinetics of dimerization of nitrosamine induced by a flash of light is measured. The experiment can be performed with a commercial ultraviolet-VIS spetrophotometer with easy to make modifications. The experiment demonstrates a flash photolysis system not always available in university chemistry laboratories.…

  7. Mass and charge distributions in chlorine-induced nuclear reactions

    SciTech Connect

    Marchetti, A.A.

    1991-12-31

    Projectile-like fragments were detected and characterized in terms of A, Z, and energy for the reactions {sup 37}Cl on {sup 40}Ca and {sup 209}Bi at E/A = 7.3 MeV, and {sup 35}Cl, on {sup 209}Bi at E/A = 15 MeV, at angles close to the grazing angle. Mass and charge distributions were generated in the N-Z plane as a function of energy loss, and have been parameterized in terms of their centroids, variances, and coefficients of correlation. Due to experimental problems, the mass resolution corresponding to the {sup 31}Cl on {sup 209}Bi reaction was very poor. This prompted the study and application of a deconvolution technique for peak enhancement. The drifts of the charge and mass centroids for the system {sup 37}Cl on {sup 40}Ca are consistent with a process of mass and charge equilibration mediated by nucleon exchange between the two partners, followed by evaporation. The asymmetric systems show a strong drift towards larger asymmetry, with the production of neutron-rich nuclei. It was concluded that this is indicative of a net transfer of protons from the light to the heavy partner, and a net flow of neutrons in the opposite direction. The variances for all systems increase with energy loss, as it would be expected from a nucleon exchange mechanism; however, the variances for the reaction {sup 37}Cl on {sup 40}Ca are higher than those expected from that mechanism. The coefficients of correlation indicate that the transfer of nucleons between projectile and target is correlated. The results were compared to the predictions of two current models based on a stochastic nucleon exchange mechanism. In general, the comparisons between experimental and predicted variances support this mechanism; however, the need for more realistic driving forces in the model calculations is indicated by the disagreement between predicted and experimental centroids.

  8. Elastic {sup 16}O+{sup 20}Ne scattering from a folding model analysis

    SciTech Connect

    Yang Yongxu; Li Qingrun

    2011-07-15

    A folding potential for elastic {sup 16}O+{sup 20}Ne scattering is constructed based on the four-{alpha}-particle model for the {sup 16}O nucleus and the {alpha}+{sup 16}O model for the {sup 20}Ne nucleus. The elastic scattering angular distributions of the {sup 16}O+{sup 20}Ne system in the energy range of E{sub c.m.}=24.5-35.5 MeV are calculated by use of the {alpha}-folding potential obtained. The calculations show that the experimental data can be reasonably well described. The surface term in the imaginary potential has a significant effect on the calculations of the cross section at large angles for the energies considered.

  9. α scattering and α -induced reaction cross sections of 64Zn at low energies

    NASA Astrophysics Data System (ADS)

    Ornelas, A.; Mohr, P.; Gyürky, Gy.; Elekes, Z.; Fülöp, Zs.; Halász, Z.; Kiss, G. G.; Somorjai, E.; Szücs, T.; Takács, M. P.; Galaviz, D.; Güray, R. T.; Korkulu, Z.; Özkan, N.; Yalçın, C.

    2016-11-01

    Background: α -nucleus potentials play an essential role for the calculation of α -induced reaction cross sections at low energies in the statistical model. Uncertainties of these calculations are related to ambiguities in the adjustment of the potential parameters to experimental elastic scattering angular distributions and to the energy dependence of the effective α -nucleus potentials. Purpose: The present work studies the total reaction cross section σreac of α -induced reactions at low energies which can be determined from the elastic scattering angular distribution or from the sum over the cross sections of all open nonelastic channels. Method: Elastic and inelastic 64Zn(α ,α )64Zn angular distributions were measured at two energies around the Coulomb barrier, at 12.1 and 16.1 MeV. Reaction cross sections of the (α ,γ ) , (α ,n ) , and (α ,p ) reactions were measured at the same energies using the activation technique. The contributions of missing nonelastic channels were estimated from statistical model calculations. Results: The total reaction cross sections from elastic scattering and from the sum of the cross sections over all open nonelastic channels agree well within the uncertainties. This finding confirms the consistency of the experimental data. At the higher energy of 16.1 MeV, the predicted significant contribution of compound-inelastic scattering to the total reaction cross section is confirmed experimentally. As a by-product it is found that most recent global α -nucleus potentials are able to describe the reaction cross sections for 64Zn around the Coulomb barrier. Conclusions: Total reaction cross sections of α -induced reactions can be well determined from elastic scattering angular distributions. The present study proves experimentally that the total cross section from elastic scattering is identical to the sum of nonelastic reaction cross sections. Thus, the statistical model can reliably be used to distribute the total reaction

  10. Reaction-induced rheological weakening enables oceanic plate subduction

    PubMed Central

    Hirauchi, Ken-ichi; Fukushima, Kumi; Kido, Masanori; Muto, Jun; Okamoto, Atsushi

    2016-01-01

    Earth is the only terrestrial planet in our solar system where an oceanic plate subducts beneath an overriding plate. Although the initiation of plate subduction requires extremely weak boundaries between strong plates, the way in which oceanic mantle rheologically weakens remains unknown. Here we show that shear-enhanced hydration reactions contribute to the generation and maintenance of weak mantle shear zones at mid-lithospheric depths. High-pressure friction experiments on peridotite gouge reveal that in the presence of hydrothermal water, increasing strain and reactions lead to an order-of-magnitude reduction in strength. The rate of deformation is controlled by pressure-solution-accommodated frictional sliding on weak hydrous phyllosilicate (talc), providing a mechanism for the ‘cutoff' of the high peak strength at the brittle-plastic transition. Our findings suggest that infiltration of seawater into transform faults with long lengths and low slip rates is an important controlling factor on the initiation of plate tectonics on terrestrial planets. PMID:27562366

  11. Theoretical cross sections of tantalum on neutron induced reactions

    NASA Astrophysics Data System (ADS)

    Siddik, Tarik

    2016-11-01

    Neutron-induced cross-sections for the stable isotope 181Ta, in the energy region up to 20 MeV have been calculated. Statistical model calculations, based on the Hauser-Feshbach formalism, have been carried out using the TALYS-1.0 and were compared with available experimental data in the literature and with ENDF/B-VII, T = 300 K; JENDL-3.3, T = 300 K and JEFF-3.1, T = 300 K evaluated libraries.

  12. Neutron-induced reactions in the hohlraum to study reaction in flight neutrons

    NASA Astrophysics Data System (ADS)

    Boswell, M. S.; Elliott, S. R.; Guiseppe, V.; Kidd, M.; Rundberg, B.; Tybo, J.

    2013-04-01

    We are currently developing the physics necessary to measure the Reaction In Flight (RIF) neutron flux from a NIF capsule. A measurement of the RIF neutron flux from a NIF capsule could be used to deduce the stopping power in the cold fuel of the NIF capsule. A foil irradiated at the Omega laser at LLE was counted at the LANL low-background counting facility at WIPP. The estimated production rate of 195Au was just below our experimental sensitivity. We have made several improvements to our counting facility in recent months. These improvements are designed to increase our sensitivity, and include installing two new low-background detectors, and taking steps to reduce noise in the signals.

  13. Analysis & Test of Reaction Wheel Induced Micro-Vibrations

    NASA Astrophysics Data System (ADS)

    Runte, Torben; Brito, Miguel; Bourne, Duncan M.; Mariani, Marco

    2014-06-01

    Microvibrations are a major disturbance source of the pointing stability for high-precision Spacecraft. These undesirable mechanical vibrations are generated by active mechanisms and transferred via the Spacecraft structure.Throughout OHB System's design of Spacecraft platforms for Spacecraft missions with high precision pointing performance, Reaction Wheels (RWs) have been identified as the most dominant source of microvibrations in Spacecraft platforms. The RW perturbations consist of numerous harmonic components whose frequencies and amplitudes depend on the wheel speed and the ball bearing characteristics of each unit. This paper focuses on the analysis methodology used to estimate the disturbance caused by these units, its transmission via the Spacecraft structure and its verification by measurement.

  14. Induced Magnetic Field Due to Reaction Wheel Shielding

    NASA Astrophysics Data System (ADS)

    Pudney, M. A.; Kapfunde, G.; Trougnou, L.

    2016-05-01

    In situ magnetic field measurements are of critical importance to unanswered questions on the inner heliosphere, such as: how the corona and solar wind are accelerated and heated; how the solar magnetic field evolves over a solar cycle; and how this field links into space. However, accurate spacecraft magnetometer measurements require reliable in-flight calibration. The magnetic interference caused by reaction wheels on magnetometer measurements in space is well known, and a common mitigation method is to use magnetic shielding. However, the presence of high-permeability material in-flight has the side-effect of distorting the true ambient field. We present a theoretical analysis of this distortion, and suggest a transfer function that can be used to recover the ambient field from the distorted dataset. Experimental measurements on a shield prototype for the Solar Orbiter mission agree with predictions to within an order of magnitude, demonstrating a distortion of approximately 1 part in 104.

  15. Hybrid isolation of micro vibrations induced by reaction wheels

    NASA Astrophysics Data System (ADS)

    Lee, Dae-Oen; Park, Geeyong; Han, Jae-Hung

    2016-02-01

    As the technology for precision satellite payloads continues to advance, the requirements for the pointing stability of the satellites are becoming extremely high. In many situations, even small amplitude disturbances generated by the onboard components may cause serious degradation in the performance of high precision payloads. In such situations, vibration isolators can be installed to reduce the vibration transmission. In this work, a hybrid vibration isolator comprising passive and active components is proposed to provide an effective solution to the vibration problems caused by the reaction wheel disturbances. Firstly, mathematical modeling and experimental study of a single axis vibration isolator having high damping and high roll-off rate for the high frequency region and active components that enhance isolation performance for narrow frequency bands are presented. This concept is then extended to multi-axis by forming Stewart platform and the performance is experimentally verified. The tests on a flexible testbed show effective vibration isolation by the proposed vibration isolator.

  16. Experimental evidence of reaction-induced fracturing during olivine carbonation

    NASA Astrophysics Data System (ADS)

    Zhu, Wenlu; Fusseis, Florian; Lisabeth, Harrison; Xing, Tiange; Xiao, Xianghui; De Andrade, Vincent; Karato, Shun-ichiro

    2016-09-01

    Mineral carbonation, a process that binds CO2 in the form of carbonates by silicate weathering, is widespread on the Earth's surface. Because of the abundance of silicate rocks and the permanence of the carbonated solids, sequestering CO2 via mineral carbonation has generated lots of interests. However, it is unclear how the fluid-rock reaction proceeds to completion in spite of an increasing solid volume. We conducted a mineral carbonation experiment in which a sintered olivine aggregate reacted with a sodium bicarbonate solution at reservoir conditions. Time-resolved synchrotron X-ray microtomographic images show cracks in polygonal patterns arising in the surface layers and propagating into the interior of the olivine aggregate. The nanotomography data reveal that the incipient cracks intersect at right angles. We infer that stretching due to nonuniform volume expansion generates polygonal cracking of the surfaces. Our data shed new lights on the processes that control hydration and carbonation of peridotite.

  17. Photo-induced chaos in the Briggs-Rauscher reaction

    NASA Astrophysics Data System (ADS)

    Okazaki, Noriaki; Hanazaki, Ichiro

    1998-07-01

    Discovery of the photo-induced chaos in the Briggs-Rauscher system is reported. The chaotic oscillations were observed between the large- and the small-amplitude simple oscillatory states existent in low and high light intensity regions, respectively. Period-doubling sequence from the large-amplitude oscillations to the chaos was observed. Deterministic nature of the chaos was confirmed by the next-amplitude return map. The stretching and folding mechanism of the trajectories was revealed through the three-dimensional attractor reconstructed via the singular value decomposition method. The chemical origin of the photoinduced chaos is discussed based on the photoautocatalysis of HIO2.

  18. Electronically induced surface reactions: Evolution, concepts, and perspectives

    SciTech Connect

    Menzel, Dietrich

    2012-09-07

    This is a personal account of the development of the title subject which is the broader field encompassing surface photochemistry. It describes the early times when the main interest centered on desorption induced by slow electrons, follows its evolution in experiment (use of synchrotron radiation and connections to electron spectroscopies; use of lasers) and mechanisms, and briefly mentions the many different subfields that have evolved. It discusses some practically important aspects and applications and ends with an account of an evolving new subfield, the application to photochemistry on nanoparticles.

  19. Artificial Force Induced Reaction (AFIR) Method for Exploring Quantum Chemical Potential Energy Surfaces.

    PubMed

    Maeda, Satoshi; Harabuchi, Yu; Takagi, Makito; Taketsugu, Tetsuya; Morokuma, Keiji

    2016-10-01

    In this account, a technical overview of the artificial force induced reaction (AFIR) method is presented. The AFIR method is one of the automated reaction-path search methods developed by the authors, and has been applied extensively to a variety of chemical reactions, such as organocatalysis, organometallic catalysis, and photoreactions. There are two modes in the AFIR method, i.e., a multicomponent mode and a single-component mode. The former has been applied to bimolecular and multicomponent reactions and the latter to unimolecular isomerization and dissociation reactions. Five numerical examples are presented for an Aldol reaction, a Claisen rearrangement, a Co-catalyzed hydroformylation, a fullerene structure search, and a nonradiative decay path search in an electronically excited naphthalene molecule. Finally, possible applications of the AFIR method are discussed.

  20. Slow slip generated by dehydration reaction coupled with slip-induced dilatancy and thermal pressurization

    NASA Astrophysics Data System (ADS)

    Yamashita, Teruo; Schubnel, Alexandre

    2016-10-01

    Sustained slow slip, which is a distinctive feature of slow slip events (SSEs), is investigated theoretically, assuming a fault embedded within a fluid-saturated 1D thermo-poro-elastic medium. The object of study is specifically SSEs occurring at the down-dip edge of seismogenic zone in hot subduction zones, where mineral dehydrations (antigorite, lawsonite, chlorite, and glaucophane) are expected to occur near locations where deep slow slip events are observed. In the modeling, we introduce dehydration reactions, coupled with slip-induced dilatancy and thermal pressurization, and slip evolution is assumed to interact with fluid pressure change through Coulomb's frictional stress. Our calculations show that sustained slow slip events occur when the dehydration reaction is coupled with slip-induced dilatancy. Specifically, slow slip is favored by a low initial stress drop, an initial temperature of the medium close to that of the dehydration reaction equilibrium temperature, a low permeability, and overall negative volume change associated with the reaction (i.e., void space created by the reaction larger than the space occupied by the fluid released). Importantly, if we do not assume slip-induced dilatancy, slip is accelerated with time soon after the slip onset even if the dehydration reaction is assumed. This suggests that slow slip is sustained for a long time at hot subduction zones because dehydration reaction is coupled with slip-induced dilatancy. Such slip-induced dilatancy may occur at the down-dip edge of seismogenic zone at hot subduction zones because of repetitive occurrence of dehydration reaction there.

  1. α and 2 p 2 n emission in fast neutron-induced reactions on 60Ni

    NASA Astrophysics Data System (ADS)

    Fotiades, N.; Devlin, M.; Haight, R. C.; Nelson, R. O.; Kunieda, S.; Kawano, T.

    2015-06-01

    Background: The cross sections for populating the residual nucleus in the reaction ZAX(n,x) Z -2 A -4Y exhibit peaks as a function of incident neutron energy corresponding to the (n ,n'α ) reaction and, at higher energy, to the (n ,2 p 3 n ) reaction. The relative magnitudes of these peaks vary with the Z of the target nucleus. Purpose: Study fast neutron-induced reactions on 60Ni. Locate experimentally the nuclear charge region along the line of stability where the cross sections for α emission and for 2 p 2 n emission in fast neutron-induced reactions are comparable as a further test of reaction models. Methods: Data were taken by using the Germanium Array for Neutron-Induced Excitations. The broad-spectrum pulsed neutron beam of the Los Alamos Neutron Science Center's Weapons Neutron Research facility provided neutrons in the energy range from 1 to 250 MeV. The time-of-flight technique was used to determine the incident-neutron energies. Results: Absolute partial cross sections for production of seven discrete Fe γ rays populated in 60Ni (n ,α /2 p x n γ ) reactions with 2 ≤x ≤5 were measured for neutron energies 1 MeVinduced reactions on stable targets via α emission at the peak of the (n ,α ) and (n ,n'α ) reactions is comparable to that for 2 p 2 n and 2 p 3 n emission at higher incident energies in the nuclear charge region around Fe.

  2. On the Measurement of the 13C(α, n)16O S-factor at Negative Energies and its Influence on the s-process

    NASA Astrophysics Data System (ADS)

    La Cognata, M.; Spitaleri, C.; Trippella, O.; Kiss, G. G.; Rogachev, G. V.; Mukhamedzhanov, A. M.; Avila, M.; Guardo, G. L.; Koshchiy, E.; Kuchera, A.; Lamia, L.; Puglia, S. M. R.; Romano, S.; Santiago, D.; Spartà, R.

    2013-11-01

    The 13C(α, n)16O reaction is the neutron source for the main component of the s-process, responsible for the production of most of the nuclei in the mass range 90 <~ A <~ 208. This reaction takes place inside the helium-burning shell of asymptotic giant branch stars, at temperatures <~ 108 K, corresponding to an energy interval where the 13C(α, n)16O reaction is effective in the range of 140-230 keV. In this regime, the astrophysical S(E)-factor is dominated by the -3 keV sub-threshold resonance due to the 6.356 MeV level in 17O, giving rise to a steep increase in the S-factor. Its contribution is still controversial as extrapolations, e.g., through the R-matrix and indirect techniques such as the asymptotic normalization coefficient (ANC), yield inconsistent results. The discrepancy amounts to a factor of three or more precisely at astrophysical energies. To provide a more accurate S-factor at these energies, we have applied the Trojan horse method (THM) to the 13C(6Li, n 16O)d quasi-free reaction. The ANC for the 6.356 MeV level has been deduced through the THM as well as the n-partial width, allowing us to attain unprecedented accuracy for the 13C(α, n)16O astrophysical factor. A larger ANC for the 6.356 MeV level is measured with respect to the ones in the literature, (\\tilde{C}_{\\alpha {}^{13}C}^{{}^{17}O(1/2^+)})^2=7.7 +/- 0.3_{stat} \\,^{+1.6}_{-1.5} \\,_{norm} fm-1, yet in agreement with the preliminary result given in our preceding letter, indicating an increase of the 13C(α, n)16O reaction rate below about 8 × 107 K if compared with the recommended values. At ~108 K, our reaction rate agrees with most of the results in the literature and the accuracy is greatly enhanced thanks to this innovative approach.

  3. Pressure-induced metathesis reaction to sequester Cs.

    PubMed

    Im, Junhyuck; Seoung, Donghoon; Lee, Seung Yeop; Blom, Douglas A; Vogt, Thomas; Kao, Chi-Chang; Lee, Yongjae

    2015-01-06

    We report here a pressure-driven metathesis reaction where Ag-exchanged natrolite (Ag16Al16Si24O80·16H2O, Ag-NAT) is pressurized in an aqueous CsI solution, resulting in the exchange of Ag(+) by Cs(+) in the natrolite framework forming Cs16Al16Si24O80·16H2O (Cs-NAT-I) and, above 0.5 GPa, its high-pressure polymorph (Cs-NAT-II). During the initial cation exchange, the precipitation of AgI occurs. Additional pressure and heat at 2 GPa and 160 °C transforms Cs-NAT-II to a pollucite-related, highly dense, and water-free triclinic phase with nominal composition CsAlSi2O6. At ambient temperature after pressure release, the Cs remains sequestered in a now monoclinic pollucite phase at close to 40 wt % and a favorably low Cs leaching rate under back-exchange conditions. This process thus efficiently combines the pressure-driven separation of Cs and I at ambient temperature with the subsequent sequestration of Cs under moderate pressures and temperatures in its preferred waste form suitable for long-term storage at ambient conditions. The zeolite pollucite CsAlSi2O6·H2O has been identified as a potential host material for nuclear waste remediation of anthropogenic (137)Cs due to its chemical and thermal stability, low leaching rate, and the large amount of Cs it can contain. The new water-free pollucite phase we characterize during our process will not display radiolysis of water during longterm storage while maintaining the Cs content and low leaching rate.

  4. Pressure induced reactions amongst calcium aluminate hydrate phases

    SciTech Connect

    Moon, Ju-hyuk; Oh, Jae Eun; Balonis, Magdalena; Glasser, Fredrik P.; Clark, Simon M.; Monteiro, Paulo J.M.

    2011-06-15

    The compressibilities of two AFm phases (straetlingite and calcium hemicarboaluminate hydrate) and hydrogarnet were obtained up to 5 GPa by using synchrotron high-pressure X-ray powder diffraction with a diamond anvil cell. The AFm phases show abrupt volume contraction regardless of the molecular size of the pressure-transmitting media. This volume discontinuity could be associated to a structural transition or to the movement of the weakly bound interlayer water molecules in the AFm structure. The experimental results seem to indicate that the pressure-induced dehydration is the dominant mechanism especially with hygroscopic pressure medium. The Birch-Murnaghan equation of state was used to compute the bulk modulus of the minerals. Due to the discontinuity in the pressure-volume diagram, a two stage bulk modulus of each AFm phase was calculated. The abnormal volume compressibility for the AFm phases caused a significant change to their bulk modulus. The reliability of this experiment is verified by comparing the bulk modulus of hydrogarnet with previous studies.

  5. The Clinical Course of a Drug-induced Acute Dystonic Reaction in the Emergency Room

    PubMed Central

    Marano, Massimo; di Biase, Lazzaro; Salomone, Gaetano; Di Santo, Alessandro; Montiroli, Annalisa; Di Lazzaro, Vincenzo

    2016-01-01

    Background Acute dystonic reactions following the administration of safe, reliable drugs can occur and must be promptly recognized and treated in the emergency room. Phenomenology Shown The entire clinical course of an acute dystonic reaction due to metoclopramide, from early motor signs to full-blown clinical symptoms and resolution. Educational Value Providing elements for early recognition of a drug-induced movement disorder phenomenology. PMID:28105387

  6. Systematic trends in photonic reagent induced reactions in a homologous chemical family.

    PubMed

    Tibbetts, Katharine Moore; Xing, Xi; Rabitz, Herschel

    2013-08-29

    The growing use of ultrafast laser pulses to induce chemical reactions prompts consideration of these pulses as "photonic reagents" in analogy to chemical reagents. This work explores the prospect that photonic reagents may affect systematic trends in dissociative ionization reactions of a homologous family of halomethanes, much as systematic outcomes are often observed for reactions between homologous families of chemical reagents and chemical substrates. The experiments in this work with photonic reagents of varying pulse energy and linear spectral chirp reveal systematic correlations between observable ion yields and the following set of natural variables describing the substrate molecules: the ionization energy of the parent molecule, the appearance energy of each fragment ion, and the relative strength of carbon-halogen bonds in molecules containing two different halogens. The results suggest that reactions induced by photonic reagents exhibit systematic behavior analogous to that observed in reactions driven by chemical reagents, which provides a basis to consider empirical "rules" for predicting the outcomes of photonic reagent induced reactions.

  7. Online monitoring of chemical reactions by polarization-induced electrospray ionization.

    PubMed

    Meher, Anil Kumar; Chen, Yu-Chie

    2016-09-21

    Polarization-induced electrospray ionization (PI-ESI) is a simple technique for instant generation of gas-phase ions directly from a microliter-sized droplet for mass spectrometric analysis. A sample droplet was placed over a dielectric substrate and in proximity (2-3 mm) to the inlet of a mass spectrometer. Owing to the polarization effect induced by the high electric field provided by the mass spectrometer, the droplet was polarized and the electrospray was generated from the apex of the droplet. The polarization-induced electrospray could last for tens of seconds, which was sufficiently long to monitor fast reactions occurring within few seconds. Thus, we demonstrated the feasibility of using the droplet-based PI-ESI MS for the online monitoring of fast reactions by simply mixing two droplets (5-10 μL) containing reactants on a dielectric substrate placed in front of a mass spectrometer applied with a high voltage (-4500 V). Schiff base reactions and oxidation reactions that can generate intermediates/products within a few seconds were selected as the model reactions. The ionic reaction species generated from intermediates and products can be simultaneously monitored by PI-ESI MS in real time. We also used this approach to selectively detect acetone from a urine sample, in which acetone was derivatized in situ. In addition, the possibility of using this approach for quantitative analysis of acetone from urine samples was examined.

  8. Prophylaxis and management of acute radiation-induced skin reactions: a systematic review of the literature

    PubMed Central

    Salvo, N.; Barnes, E.; van Draanen, J.; Stacey, E.; Mitera, G.; Breen, D.; Giotis, A.; Czarnota, G.; Pang, J.; De Angelis, C.

    2010-01-01

    Radiation therapy is a common treatment for cancer patients. One of the most common side effects of radiation is acute skin reaction (radiation dermatitis) that ranges from a mild rash to severe ulceration. Approximately 85% of patients treated with radiation therapy will experience a moderate-to-severe skin reaction. Acute radiation-induced skin reactions often lead to itching and pain, delays in treatment, and diminished aesthetic appearance—and subsequently to a decrease in quality of life. Surveys have demonstrated that a wide variety of topical, oral, and intravenous agents are used to prevent or to treat radiation-induced skin reactions. We conducted a literature review to identify trials that investigated products for the prophylaxis and management of acute radiation dermatitis. Thirty-nine studies met the pre-defined criteria, with thirty-three being categorized as prophylactic trials and six as management trials. For objective evaluation of skin reactions, the Radiation Therapy Oncology Group criteria and the U.S. National Cancer Institute Common Toxicity Criteria were the most commonly used tools (65% of the studies). Topical corticosteroid agents were found to significantly reduce the severity of skin reactions; however, the trials of corticosteroids evaluated various agents, and no clear indication about a preferred corticosteroid has emerged. Amifostine and oral enzymes were somewhat effective in preventing radiation-induced skin reactions in phase ii and phase iii trials respectively; further large randomized controlled trials should be undertaken to better investigate those products. Biafine cream (Ortho–McNeil Pharmaceuticals, Titusville, NJ, U.S.A.) was found not to be superior to standard regimes in the prevention of radiation-induced skin reactions (n = 6). In conclusion, the evidence is insufficient to support the use of a particular agent for the prevention and management of acute radiation-induced skin reactions. Future trials should focus

  9. The Status of Cross Section Measurements for Neutron-induced Reactions Needed for Cosmic Ray Studies

    NASA Technical Reports Server (NTRS)

    Sisterson, J. M.

    2003-01-01

    Cosmic ray interactions with lunar rocks and meteorites produce small amounts of radionuclides and stable isotopes. Advances in Accelerator Mass Spectrometry (AMS) allow production rates to be measured routinely in well-documented lunar rocks and meteorites. These measurements are analyzed using theoretical models to learn about the object itself and the history of the cosmic rays that fell on it. Good cross section measurements are essential input to the theoretical calculations. Most primary cosmic ray particles are protons so reliable cross sections for proton-induced reactions are essential. A cross section is deemed accurate if measurements made by different experimenters using different techniques result in consistent values. Most cross sections for proton induced reactions are now well measured. However, good cross section measurements for neutron-induced reactions are still needed. These cross sections are required to fully account for all galactic cosmic ray interactions at depth in an extraterrestrial object. When primary galactic cosmic ray (GCR) particles interact with an object many secondary neutrons are produced, which also initiate spallation reactions. Thus, the total GCR contribution to the overall cosmogenic nuclide archive has to include the contribution from the secondary neutron interactions. Few relevant cross section measurements have been reported for neutron-induced reactions at neutron energies greater than approximately 20 MeV. The status of the cross section measurements using quasi-monoenergetic neutron energies at iThemba LABS, South Africa and white neutron beams at Los Alamos Neutron Science Center (LANSCE), Los Alamos are reported here.

  10. Neutron-induced reactions on AlF3 studied using the optical model

    NASA Astrophysics Data System (ADS)

    Ma, Chun-Wang; Lv, Cui-Juan; Zhang, Guo-Qiang; Wang, Hong-Wei; Zuo, Jia-Xu

    2015-08-01

    Neutron-induced reactions on 27Al and 19F nuclei are investigated using the optical model implemented in the TALYS 1.4 toolkit. Incident neutron energies in a wide range from 0.1 keV to 30 MeV are calculated. The cross sections for the main channels (n, np), (n, p), (n, α), (n, 2n), and (n, γ) and the total reaction cross section (n, tot) of the reactions are obtained. When the default parameters in TALYS 1.4 are adopted, the calculated results agree with the measured results. Based on the calculated results for the n + 27Al and n + 19F reactions, the results of the n + 27Al19F reactions are predicted. These results are useful both for the design of thorium-based molten salt reactors and for neutron activation analysis techniques.

  11. Cetirizine-induced acute generalized exanthematous pustulosis: a serious reaction to a commonly used drug.

    PubMed

    Badawi, Ahmed H; Tefft, Kimberly; Fraga, Garth R; Liu, Deede Y

    2014-05-16

    Acute generalized exanthematous pustulosis (AGEP) is an abrupt cutaneous adverse reaction usually in response to medications. It is generally a self-limiting disease if diagnosed promptly and the offending agent discontinued. Cetirizine, a commonly used anti-histamine medication for the treatment of allergic diseases has few reported side effects and is normally well-tolerated and effective. Herein, the first reported case of cetirizine induced AGEP is presented, followed by a discussion of the clinical and pathological aspects of this adverse cutaneous reaction to a widely used drug. Awareness of this reaction is vital owing to the extensive use of cetirizine and the importance of drug cessation once the reaction is identified. Lastly, other pustular cutaneous reactions may present similarly and therefore accurate identification of this disease can prevent unnecessary diagnostic testing.

  12. Effect of divalent ions in acrosome reaction induced by glycosamineglycans in porcine spermatozoa.

    PubMed

    Delgado, N M; Carranco, A; Merchant, H; Reyes, R

    1985-01-01

    Magnesium, calcium, and zinc at the concentration of 10 microM are capable of inducing a "true" acrosome reaction in the pig spermatozoa judged by the criteria of the fusion of the acrosome and the plasmatic membrane at the anterior region or the sperm nucleus. The optimal percent of acrosome reaction reached by any of the ions tested as a whole was 50%. When glycosamineglycan sulfate (GAGs) plus 10 microM of Mg++, Ca++, or Zn++ was added, they reach to 70-80% of acrosome reaction. At the electrom microscope, thin sections taken from pig spermatozoa treated with ions, GAGs, or ion + GAGs under optimal experimental conditions revealed the same pattern of acrosomal reaction. Results suggest the important role that divalent cations play in general in the induction of the acrosome reaction and question the so-called essential role of calcium ions.

  13. Real-time electron dynamics simulation of two-electron transfer reactions induced by nuclear motion

    NASA Astrophysics Data System (ADS)

    Suzuki, Yasumitsu; Yamashita, Koichi

    2012-04-01

    Real-time electron dynamics of two-electron transfer reactions induced by nuclear motion is calculated by three methods: the numerically exact propagation method, the time-dependent Hartree (TDH) method and the Ehrenfest method. We find that, as long as the nuclei move as localized wave packets, the TDH and Ehrenfest methods can reproduce the exact electron dynamics of a simple charge transfer reaction model containing two electrons qualitatively well, even when nonadiabatic transitions between adiabatic states occur. In particular, both methods can reproduce the cases where a complete two-electron transfer reaction occurs and those where it does not occur.

  14. An Experimental Study on What Controls the Ratios of 18O/16O and 17O/16O of O2 During Microbial Respiration

    NASA Astrophysics Data System (ADS)

    Stolper, D. A.; Ward, B. B.; Fischer, W. W.; Bender, M. L.

    2015-12-01

    18O/16O and 17O/16O ratios of atmospheric and dissolved oceanic O2 are key biogeochemical tracers of total photosynthesis and respiration on global to local length scales and glacial/interglacial time scales (Luz et al., 1999). Critical to the use of these ratios as biogeochemical tracers is knowledge of how they are affected by production, consumption, and transport of O2. We present new measurements of O2 respiration by E. coli and N. oceanus, an ammonia oxidizing bacterium, to test three assumptions of isotopically enabled models of the O2 cycle: (i) laboratory-measured respiratory 18O/16O isotope effects (18α) of microorganisms are constant under all experimental and natural conditions (e.g., temperature and growth rate); (ii) the respiratory 'mass law' relationship between 18O/16O and 17O/16O [17α = (18α)β] is universal; and (iii) 18α and β for aerobic ammonia and organic carbon oxidation are identical. For E. coli, we find that both 18α and β are variable. From 37°C to 15°C, 18α varies linearly with temperature from 17 to 14‰, and β varies linearly from 0.513 to 0.508. 18α and β do not appear to vary with growth rate (as tested using different carbon sources). Both 18α and β are lower than previous observations for bacteria: 18α = 17-20‰ (Kiddon et al., 1993) and β = 0.515 (Luz and Barkan, 2005). We were able to simulate the observed temperature dependence of 18α and β using a model of respiration with two isotopically discriminating steps: O2 binding to cytochrome bo oxidase (the respiratory enzyme) and reduction of O2 to H2O. Finally, initial results on N. oceanus suggest it has similar values for 18α and β as previously studied aerobic bacteria that consume organic carbon, providing the first support for assumption (iii). Based on these results, isotopically constrained biogeochemical models of O2 cycling may need to consider a temperature dependence for 18α and β for microbial respiration. For example, these results may

  15. RADIATIVE NEUTRON CAPTURE ON 9Be, 14C, 14N, 15N AND 16O AT THERMAL AND ASTROPHYSICAL ENERGIES

    NASA Astrophysics Data System (ADS)

    Dubovichenko, Sergey; Dzhazairov-Kakhramanov, Albert; Afanasyeva, Nadezhda

    2013-10-01

    The total cross-sections of the radiative neutron capture processes on 9Be, 14C, 14N, 15N and 16O are described in the framework of the modified potential cluster model with the classification of orbital states according to Young tableaux. The continued interest in the study of these reactions is due, on the one hand, to the important role played by this process in the analysis of many fundamental properties of nuclei and nuclear reactions, and, on the other hand, to the wide use of the capture cross-section data in the various applications of nuclear physics and nuclear astrophysics, and, also, to the importance of the analysis of primordial nucleosynthesis in the Universe. This article is devoted to the description of results for the processes of the radiative neutron capture on certain light atomic nuclei at thermal and astrophysical energies. The considered capture reactions are not part of stellar thermonuclear cycles, but involve in the reaction chains of inhomogeneous Big Bang models.

  16. Pharmacogenomics of drug-induced hypersensitivity reactions: challenges, opportunities and clinical implementation.

    PubMed

    Sukasem, Chonlaphat; Puangpetch, Apichaya; Medhasi, Sadeep; Tassaneeyakul, Wichittra

    2014-06-01

    Drug hypersensitivity reactions affect many patients leading to a variety of clinical manifestations, mainly the cutaneous adverse reactions ranging from milder skin reactions to severe cutaneous adverse reactions (SCARs). Hypersensitivity reactions are unpredictable and are thought to have an underlying genetic etiology, as suggested by case reports. With the scientific knowledge of pharmacogenomics and the evidence based on the genomic testing, it is possible to identify genetic predisposing factors for these serious adverse reactions and personalize drug therapy. The most significant genetic associations have been identified in the major histocompatibility complex (MHC) genes encoded for human leukocyte antigens (HLA) alleles. Drugs associated with hypersensitivity reactions with strong genetic predisposing factors include abacavir, nevirapine, carbamazepine, and allopurinol. In this review, strong genetic associations of drug-induced SCARs are highlighted so as to improve drug safety and help to select optimal drugs for individual patients. Further investigation, however, is essential for the characterization of other genes involved in the hypersensitivity reactions with the use of several genetic strategies and technologies.

  17. Double Folding Potential of Different Interaction Models for 16O + 12C Elastic Scattering

    NASA Astrophysics Data System (ADS)

    Hamada, Sh.; Bondok, I.; Abdelmoatmed, M.

    2016-12-01

    The elastic scattering angular distributions for 16O + 12C nuclear system have been analyzed using double folding potential of different interaction models: CDM3Y1, CDM3Y6, DDM3Y1 and BDM3Y1. We have extracted the renormalization factor N r for the different concerned interaction models. Potential created by BDM3Y1 model of interaction has the shallowest depth which reflects the necessity to use higher renormalization factor. The experimental angular distributions for 16O + 12C nuclear system in the energy range 115.9-230 MeV exhibited unmistakable refractive features and rainbow phenomenon.

  18. New measurements and phase shift analysis of p16O elastic scattering at astrophysical energies

    NASA Astrophysics Data System (ADS)

    Dubovichenko, Sergey; Burtebayev, Nassurlla; Dzhazairov-Kakhramanov, Albert; Zazulin, Denis; Kerimkulov, Zhambul; Nassurlla, Marzhan; Omarov, Chingis; Tkachenko, Alesya; Shmygaleva, Tatyana; Kliczewski, Stanislaw; Sadykov, Turlan

    2017-01-01

    The results of new experimental measurements of p16O elastic scattering in the energy range of 0.6-1.0 MeV at angles of 40°-160° are given. Phase shift analysis of p16O elastic scattering was made using these and other experimental data on differential cross sections in excitation functions and angular distributions at energies of up to 2.5 MeV. Supported by the Ministry of Education and Science of the Republic of Kazakhstan (0073/PCF-IS-MES)

  19. Spectral linelist of HD16O molecule based on VTT calculations for atmospheric application

    NASA Astrophysics Data System (ADS)

    Voronin, B. A.

    2014-11-01

    Three version line-list of dipole transition for isotopic modification of water molecule HD16O are presented. Line-lists have been created on the basis of VTT calculations (Voronin, Tennyson, Tolchenov et al. MNRAS, 2010) by adding air- and self-broadening coefficient, and temperature exponents for HD16O-air case. Three cut-of values for the line intensities were used: 1e-30, 1e-32 and 1e-35 cm/molecule. Calculated line-lists are available on the site ftp://ftp.iao.ru/pub/VTT/VTT-296/.

  20. Thermally-induced amphibole reaction rim development: EBSD insights into microlite orientation

    NASA Astrophysics Data System (ADS)

    De Angelis, Sarah; Lavallée, Yan; Larsen, Jessica; Mariani, Elisabetta

    2014-05-01

    Amphibole is an important mineral present in many calc-alkaline volcanic deposits. A hydrous phase, volcanic amphibole is only stable at pressures greater than 100 MPa (approx. 4 km), temperature less than ~860-870 oC, and in melts containing at least 4 wt % H2O. When removed from their thermal and barometric stability field, amphiboles decompose to form aggregate rims of anhydrous minerals. The thickness, texture, and mineralogy of these rims are thought to be reflective of the process driving amphibole disequilibrium (e.g. heating, decompression, etc). However, significant overlap in rim thicknesses and microlite textures means that distinguishing between processes it not simple. This study employed backscatter diffraction (EBSD) to examine both experimental heating-indced amphibole reaction rims and natural amphibole reaction rim from Augustine Volcano. We collected crystal orientation maps of amphibole reaction rims to investigate if different types of disequilibrium produce different patterns of microlite orientation. We identified two types of reaction rim: Type 1- reaction rim microlites are generally oriented at random and share little or no systematic relationship with the crystallographic orientation of the host amphibole, and; Type 2- reaction rim microlites exhibit a topotactic relationship with the host amphibole (they share the same crystallographic orientation). Experimentally produced heating reaction rims are without exception Type 2. However the natural reaction rims are evenly distributed between Types 1 and 2. Further experimental data on decompression induced reaction rim formation is needed to investigate if Type 1 reaction rims resemble the breakdown of amphibole due to decompression. If so, reaction rim microlite orientation could provide a clear method for distinguishing between heating and decompression processes in amphibole bearing magmas.

  1. Cold-induced precipitation of a monoclonal IgM: a negative activation enthalpy reaction.

    PubMed

    Meliga, Stefano C; Farrugia, William; Ramsland, Paul A; Falconer, Robert J

    2013-01-17

    Cold-induced precipitation of a monoclonal IgM cryoglobulin isolated from a patient with Waldenström's macroglobulinemia was observed to have a negative activation enthalpy. The rate of the reaction increased, as the temperature decreased. Differential scanning calorimetry of the monoclonal IgM showed precipitation as an inverted peak during a downward temperature scan. The transition temperature was between 14 and 15 °C and was possibly concentration dependent. At temperatures below the transition the precipitation was best described by second-order kinetics. The difference in change in enthalpy between precipitation and disassociation suggests that cold-induced precipitation had a fast precipitation stage followed by a slower consolidation reaction. Negligible curvature of the Eyring plot suggested the precipitation reaction was dominated by van der Waal forces and hydrogen bonding. Conversely, during an upward temperature scan, disassociation was observed as a positive enthalpy peak. This reaction had two stages, a reaction undoing consolidation followed by heat-induced disassociation that had first-order kinetics.

  2. Energy and volume changes induced by photoinitiated proton releasing reaction with apomyoglobin

    NASA Astrophysics Data System (ADS)

    Choi, Jungkwon; Terazima, Masahide

    2003-01-01

    The photodissociation reaction of o-nitrobenzaldehyde (NBA) aqueous solution and of the NBA solution with a protein, apomyoglobin (ApoMb), were studied by the time-resolved transient grating (TG) technique. The amount of released thermal energy and the volume change accompanied with this reaction were determined by the TG and photoacoustic method. Without the protein, the photoproduct of NBA releases a proton in the solution (pH jump reaction). The time profile of the grating signal of NBA and ApoMb shows two diffusing species with diffusion coefficients of 1.39±0.15 and 0.14±0.02×10-9 m2 s-1, respectively. From the diffusion coefficients, we suggest that the photoproduct of NBA induces a molecular recombination reaction between ApoMb and another small molecule or ion in the solution.

  3. Low and medium energy deuteron-induced reactions on {sup 27}Al

    SciTech Connect

    Bem, P.; Simeckova, E.; Honusek, M.; Fischer, U.; Simakov, S. P.; Forrest, R. A.; Avrigeanu, M.; Obreja, A. C.; Roman, F. L.; Avrigeanu, V.

    2009-04-15

    The activation cross sections of (d,p), (d,2p), and (d,p{alpha}) reactions on {sup 27}Al were measured in the energy range from 4 to 20 MeV using the stacked-foils technique. Following a previous extended analysis of elastic scattering, breakup, and direct reaction of deuterons on {sup 27}Al, for energies from 3 to 60 MeV, the preequilibrium and statistical emissions are considered in the same energy range. Finally, all deuteron-induced reactions on {sup 27}Al including the present data measured up to 20 MeV deuteron energy are properly described due to a simultaneous analysis of the elastic scattering and reaction data.

  4. Noise-and delay-induced phase transitions of the dimer-monomer surface reaction model

    NASA Astrophysics Data System (ADS)

    Zeng, Chunhua; Wang, Hua

    2012-06-01

    The effects of noise and time-delayed feedback in the dimer-monomer (DM) surface reaction model are investigated. Applying small delay approximation, we construct a stochastic delayed differential equation and its Fokker-Planck equation to describe the state evolution of the DM reaction model. We show that the noise can only induce first-order irreversible phase transition (IPT) characteristic of the DM model, however the combination of the noise and time-delayed feedback can simultaneously induce first- and second-order IPT characteristics of the DM model. Therefore, it is shown that the well-known first- and second-order IPT characteristics of the DM model may be viewed as noise-and delay-induced phase transitions.

  5. Determination of 16O and 18O sensitivity factors and charge-exchange processes in low-energy ion scattering

    NASA Astrophysics Data System (ADS)

    Téllez, H.; Chater, R. J.; Fearn, S.; Symianakis, E.; Brongersma, H. H.; Kilner, J. A.

    2012-10-01

    Quantitative analysis in low-energy ion scattering (LEIS) requires an understanding of the charge-exchange processes to estimate the elemental sensitivity factors. In this work, the neutralization of He+ scattered by 18O-exchanged silica at energies between 0.6 and 7 keV was studied. The process is dominated by Auger neutralization for Ei < 0.8 keV. An additional mechanism starts above the reionization threshold. This collision-induced neutralization becomes the dominant mechanism for Ei > 2 keV. The ion fractions P+ were determined for Si and O using the characteristic velocity method to quantify the surface density. The 18O/16O sensitivity ratio indicates an 18% higher sensitivity for the heavier O isotope.

  6. Deuteron-induced reactions on Ni isotopes up to 60 MeV

    NASA Astrophysics Data System (ADS)

    Avrigeanu, M.; Šimečková, E.; Fischer, U.; Mrázek, J.; Novak, J.; Štefánik, M.; Costache, C.; Avrigeanu, V.

    2016-07-01

    Background: The high complexity of the deuteron-nucleus interaction from the deuteron weak binding energy of 2.224 MeV is also related to a variety of reactions induced by the deuteron-breakup (BU) nucleons. Thus, specific noncompound processes as BU and direct reactions (DR) make the deuteron-induced reactions so different from reactions with other incident particles. The scarce consideration of only pre-equilibrium emission (PE) and compound-nucleus (CN) mechanisms led to significant discrepancies with experimental results so that recommended reaction cross sections of high-priority elements as, e.g., Ni have mainly been obtained by fit of the data. Purpose: The unitary and consistent BU and DR account in deuteron-induced reactions on natural nickel may take advantage of an extended database for this element, including new accurate measurements of particular reaction cross sections. Method: The activation cross sections of 64,61,60Cu, Ni,5765, and 55,56,57,58,59m,60Co nuclei for deuterons incident on natural Ni at energies up to 20 MeV, were measured by the stacked-foil technique and high-resolution gamma spectrometry using U-120M cyclotron of CANAM, NPI CAS. Then, within an extended analysis of deuteron interactions with Ni isotopes up to 60 MeV, all processes from elastic scattering until the evaporation from fully equilibrated compound system have been taken into account while an increased attention is paid especially to the BU and DR mechanisms. Results: The deuteron activation cross-section analysis, completed by consideration of the PE and CN contributions corrected for decrease of the total-reaction cross section from the leakage of the initial deuteron flux towards BU and DR processes, is proved satisfactory for the first time to all available data. Conclusions: The overall agreement of the measured data and model calculations validates the description of nuclear mechanisms taken into account for deuteron-induced reactions on Ni, particularly the BU and

  7. Isotope 18 O 16 O Ratio Measurements of Water Vapor by use of Photoacoustic Spectroscopy

    NASA Astrophysics Data System (ADS)

    Matsumi, Yutaka; Kishigami, Masahiro; Tanaka, Noriyuki; Kawasaki, Masahiro; Inoue, Gen

    1998-09-01

    We applied a photoacoustic spectroscopy technique to isotope ratio measurements of 16 O and 18 O in water-vapor samples, using a pulsed tunable dye laser pumped by a Nd:YAG laser. The fourth overtone bands (4 OH ) of water molecules near 720 nm were investigated. We identified the absorption lines of H 2 16 O and H 2 18 O in the photoacoustic spectra that we measured by using an 18 O-enriched water sample and the HITRAN database. We measured the difference in the 18 O 16 O isotope ratios for normal distilled water and Antarctic ice, using the photoacoustic method. The value obtained for the difference between the two samples is 18 O 32 16 , where the indicated deviation was a 1 value among 240-s measurements, whereas the value measured with a conventional isotope mass spectrometer was 18 O 28 2 . This method is demonstrated to have the potential of a transportable system for in situ and quick measurements of the H 2 18 O H 2 16 O ratio in the environment.

  8. Experimental study to explore the 8Be-induced nuclear reaction via the Trojan horse method

    NASA Astrophysics Data System (ADS)

    Wen, Qun-Gang; Li, Cheng-Bo; Zhou, Shu-Hua; Irgaziev, Bakhadir; Fu, Yuan-Yong; Spitaleri, Claudio; La Cognata, Marco; Zhou, Jing; Meng, Qiu-Ying; Lamia, Livio; Lattuada, Marcello

    2016-03-01

    To explore a possible indirect method for 8Be induced astrophysical reactions, the 8Be=(8Be+n ) cluster structure has been studied via the Trojan horse method. For the first time a 8Be nucleus having an ultrashort lifetime is studied by the Trojan horse method and a 9Be nucleus in the ground state is used for this purpose. The 9Be nucleus is assumed to have a (8Be+n ) cluster structure and used as a Trojan horse nucleus. The 8Be nucleus acts as a participant, while the neutron is a spectator to the virtual 8Be+d →α +6Li reaction via the 3-body reaction 8Be+d →α +6Li+n . The experimental neutron momentum distribution inside 9Be has been reconstructed. The agreement between the experimental momentum distribution and the theoretical one indicates that a (8Be+n ) cluster structure inside 9Be is very likely. Therefore, the experimental study of 8Be induced reactions, for example, the measurement of the 8Be+α →12C reaction proceeding through the Hoyle state, is possible.

  9. Determination of the delta(18O/16O)of Water: RSIL Lab Code 489

    USGS Publications Warehouse

    Revesz, Kinga; Coplen, Tyler

    2008-01-01

    The purpose of the technique described by the Reston Stable Isotope Laboratory (RSIL) lab code 489 is to present a method to determine the delta(180/160), abbreviated as delta-180, of water. This delta-18O measurement of water also is a component of National Water Quality Laboratory (NWQL in USGS) schedules 1142 and 1172. Water samples are loaded into glass sample containers on a vacuum manifold to equilibrate gaseous CO2 at constant temperature (25 deg C) with water samples. After loading water samples on the vacuum manifold, air is evacuated through capillary to avoid evaporation, and CO2 is added. The samples are shaken to increase the equilibration rate of water and CO2. When isotopic equilibrium has been attained, an aliquot of CO2 is extracted sequentially from each sample container, separated from water vapor by means of a dry ice trap, and introduced into a dual-inlet isotope-ratio mass spectrometer (DI-IRMS) for determination of the delta-18O value. There is oxygen isotopic fractionation between water and CO2, but it is constant at constant temperature. The DI-IRMS is a DuPont double-focusing mass spectrometer. It has a double collector. One ion beam passes through a slit in a forward collector and is collected in the rear collector. The other ion beams are collected in the front collector. The instrument is capable of measuring mass/charge (m/z) 44 and 45 or 44 and 46 by changing the ion-accelerating voltage under computer control. The ion beams from these m/z values are as follows: m/z 44=CO2=12C16O16O, m/z 45=CO2=13C16O16O primarily, and m/z 46 = CO2=12C16O18O primarily. The data acquisition and control software calculates delta-18O values.

  10. Field-resolved measurement of reaction-induced spectral densities by polarizability response spectroscopy

    NASA Astrophysics Data System (ADS)

    Moran, Andrew M.; Nome, Rene A.; Scherer, Norbert F.

    2007-11-01

    The experimental design and theoretical description of a novel five-pulse laser spectroscopy is presented with an application to a pyridinium charge transfer complex in acetonitrile and methanol. In field-resolved polarizability response spectroscopy (PORS), an electronically resonant laser pulse first excites a solvated chromophore (reactant) and off-resonant Raman spectra of the resulting nuclear motions are measured as a function of the reaction time. The present apparatus differs from our earlier design by performing the Raman probe measurement (with fixed pulse delays) in the frequency domain. In addition, the full electric fields of the signals are measured by spectral interferometry to separate nonresonant and Raman responses. Our theoretical model shows how the PORS signal arises from nuclear motions that are displaced/driven by the photoinduced reaction. The field-resolved off-resonant (of the solute's electronic transitions) probing favors detection of solvent (as opposed to solute) dynamics coupled to the reaction. The sign of the signal represents the relative strengths of polarization responses associated with the ground and photoexcited solutions. Signatures of nonresonant and PORS signal contributions to the experimental results are analyzed with numerical calculations based on a theoretical model we have developed for reaction-induced PORS. Our model identifies two mechanisms of PORS signal generation: (i) structural relaxation induced resonance; (ii) dephasing induced resonance. In the charge transfer reaction investigated, the solvent-dependent and time-evolving (solvent) polarizability spectral density (PSD) is readily obtained. The general trend of an initial broadband inertial nuclear response followed by a decrease in the linewidth of the PSD establishes that the measured PSD is inconsistent with the approximation of a linear response. Furthermore, the explicit time evolution of the PSD is important for properly describing solvent control of

  11. Experimental Study of the Cross Sections of α-Particle Induced Reactions on 209Bi

    NASA Astrophysics Data System (ADS)

    Hermanne, A.; Tárkányi, F.; Takács, S.; Szúcs, Z.

    2005-05-01

    Alpha particle induced reactions for generation of 211At used in therapeutic nuclear medicine and possible contaminants were investigated with the stacked foil activation technique on natural bismuth targets up to Eα=39 MeV. Excitation functions for the reactions 209Bi(α,2n)211At, 209Bi(α,3n)210At, 209Bi(α,x) 210Po obtained from direct alpha emission measurements and gamma spectra from decay products are compared with earlier literature values. Thick target yields have been deduced from the experimental cross sections.

  12. Experimental Study of the Cross Sections of {alpha}-Particle Induced Reactions on 209Bi

    SciTech Connect

    Hermanne, A.; Tarkanyi, F.; Takacs, S.; Szucs, Z.

    2005-05-24

    Alpha particle induced reactions for generation of 211At used in therapeutic nuclear medicine and possible contaminants were investigated with the stacked foil activation technique on natural bismuth targets up to E{alpha}=39 MeV. Excitation functions for the reactions 209Bi({alpha},2n)211At, 209Bi({alpha},3n)210At, 209Bi({alpha},x) 210Po obtained from direct alpha emission measurements and gamma spectra from decay products are compared with earlier literature values. Thick target yields have been deduced from the experimental cross sections.

  13. Cocaine-induced dystonic reaction: an unlikely presentation of child neglect.

    PubMed

    Pinto, Jamie M; Babu, Kavita; Jenny, Carole

    2013-09-01

    Child neglect can be difficult to recognize. Parental substance abuse may place a child at increased risk of neglect. This report reviews 2 cases of dystonic reaction in children after accidental exposure to cocaine in their home environments. The reports are followed by a review of proposed physiologic mechanisms for cocaine-induced dystonia and a discussion on neurological symptoms that may develop after cocaine exposure. Pediatric emergency physicians should consider cocaine exposure when a child of any age presents with abnormal movements. Dystonic reaction is an uncommon, but reported, complication of cocaine exposure in the absence of other risk factors and may be the first presentation of child neglect.

  14. Evolving model-free scattering matrix via evolutionary algorithm: {sup 16}O-{sup 16}O elastic scattering at 350 MeV

    SciTech Connect

    Korda, V.Yu.; Molev, A.S.; Korda, L.P.

    2005-07-01

    We present a new procedure that enables us to extract a scattering matrix S(l) as a complex function of angular momentum directly from the scattering data without any a priori model assumptions implied. The key ingredient of the procedure is the evolutionary algorithm with diffused mutation that evolves the population of the scattering matrices by means of their smooth deformations from the primary arbitrary analytical S(l) shapes to the final ones, giving high-quality fits to the data. Because of the automatic monitoring of the scattering-matrix derivatives, the final S(l) shapes are monotonic and do not have any distortions. For the {sup 16}O-{sup 16}O elastic-scattering data at 350 MeV, we show the independence of the final results of the primary S(l) shapes. Contrary to other approaches, our procedure provides an excellent fit by the S(l) shapes that support the 'rainbow' interpretation of the data under analysis.

  15. Elastic scattering of {sup 16}O+{sup 16}O at energies E/A between 5 and 8 MeV

    SciTech Connect

    Nicoli, M. P.; Haas, F.; Freeman, R. M.; Aissaoui, N.; Beck, C.; Elanique, A.; Nouicer, R.; Morsad, A.; Szilner, S.; Basrak, Z.

    1999-12-01

    The elastic scattering of {sup 16}O+{sup 16}O has been measured at nine energies between E{sub lab}=75 and 124 MeV. The data cover up to 100 degree sign in the c.m. and can be described in terms of phenomenological and folding model potentials which reproduce the main features observed. In agreement with studies at higher energies in this and similar systems, refractive effects are present in the angular distributions at all energies. In particular, the passage of Airy minima through 90 degree sign at E{sub c.m.}=40, 47.5, and 62 MeV explains the deep minima observed in the excitation function. The real part of the optical potential is found to vary very little with energy over the studied interval, but the imaginary part shows a rapid change in its shape at incident energy about 90 MeV. Nonetheless, the energy dependence of the volume integral of the real and imaginary parts is in agreement with dispersion relation predictions. (c) 1999 The American Physical Society.

  16. HLA-A★3101 and Carbamazepine-Induced Hypersensitivity Reactions in Europeans

    PubMed Central

    McCormack, Mark; Alfirevic, Ana; Bourgeois, Stephane; Farrell, John J.; Kasperavičiūtė, Dalia; Carrington, Mary; Sills, Graeme J.; Marson, Tony; Jia, Xiaoming; de Bakker, Paul I.W.; Chinthapalli, Krishna; Molokhia, Mariam; Johnson, Michael R.; O’Connor, Gerard D.; Chaila, Elijah; Alhusaini, Saud; Shianna, Kevin V.; Radtke, Rodney A.; Heinzen, Erin L.; Walley, Nicole; Pandolfo, Massimo; Pichler, Werner; Park, B. Kevin; Depondt, Chantal; Sisodiya, Sanjay M.; Goldstein, David B.; Deloukas, Panos; Delanty, Norman; Cavalleri, Gianpiero L.; Pirmohamed, Munir

    2011-01-01

    BACKGROUND Carbamazepine causes various forms of hypersensitivity reactions, ranging from maculopapular exanthema to severe blistering reactions. The HLA-B★1502 allele has been shown to be strongly correlated with carbamazepine-induced Stevens–Johnson syndrome and toxic epidermal necrolysis (SJS–TEN) in the Han Chinese and other Asian populations but not in European populations. METHODS We performed a genomewide association study of samples obtained from 22 subjects with carbamazepine-induced hypersensitivity syndrome, 43 subjects with carbamazepine-induced maculopapular exanthema, and 3987 control subjects, all of European descent. We tested for an association between disease and HLA alleles through proxy single-nucleotide polymorphisms and imputation, confirming associations by high-resolution sequence-based HLA typing. We replicated the associations in samples from 145 subjects with carbamazepine-induced hypersensitivity reactions. RESULTS The HLA-A★3101 allele, which has a prevalence of 2 to 5% in Northern European populations, was significantly associated with the hypersensitivity syndrome (P = 3.5×10−8). An independent genomewide association study of samples from subjects with maculopapular exanthema also showed an association with the HLA-A★3101 allele (P = 1.1×10−6). Follow-up genotyping confirmed the variant as a risk factor for the hypersensitivity syndrome (odds ratio, 12.41; 95% confidence interval [CI], 1.27 to 121.03), maculopapular exanthema (odds ratio, 8.33; 95% CI, 3.59 to 19.36), and SJS–TEN (odds ratio, 25.93; 95% CI, 4.93 to 116.18). CONCLUSIONS The presence of the HLA-A★3101 allele was associated with carbamazepine-induced hypersensitivity reactions among subjects of Northern European ancestry. The presence of the allele increased the risk from 5.0% to 26.0%, whereas its absence reduced the risk from 5.0% to 3.8%. (Funded by the U.K. Department of Health and others.) PMID:21428769

  17. Propranolol-induced gingival hyperplasia with Nager syndrome: A rare adverse drug reaction

    PubMed Central

    Raheel, Syed Ahamed; Kujan, Omar Bashar; Tarakji, Bassel; Umar, Dilshad; Ibrahim, Salah

    2016-01-01

    Drug reactions are a group of reactionary lesions generally show their manifestations in the oral cavity. The drug reactions may vary from local rashes to well-developed swellings in the oral cavity especially involving the gingiva. Most of the drug reactions are asymptomatic and commonly triggered from the active metabolite of a drug used for a long time. Nager syndrome is a group of acrofacial dysostosis that usually results in craniofacial and limb malformations. The craniofacial defects are very similar to the mandibulofacial dysostosis. A very early intervention is needed for the habilitation of the patient especially when it is concerned with speech and language development. This paper reports a case of a 32-year-old female with craniofacial, limb, and skeletal abnormalities along with a drug-induced gingival hyperplasia. PMID:27144155

  18. Threshold and spin factors in the yield of bremsstrahlung-induced reactions

    SciTech Connect

    Karamian, S. A.

    2013-12-15

    Relative yields of photon-induced reactions are systematized in a function of the threshold parameter for moderately heavy targets at the bremsstrahlung end-point energy lower than 30 MeV. Regular dependence is established for the group of (γ, n), (γ, p), and (γ, d) reactions, while the yields of (γ, 2n) and (γ,α) reactions deviate from the regularity. Physical conclusions are discussed and possible application of this systematic for data processing is proposed. In particular, the constituent threshold and spin factors in the isomer-to-ground-state ratio could be isolated separately. For spin dependence of the yields, a new regularization parameter is introduced and previously hidden peculiarities are concluded.

  19. A thermochemical model for shock-induced reactions (heat detonations) in solids

    NASA Astrophysics Data System (ADS)

    Boslough, Mark B.

    1990-02-01

    Recent advances in studies of shock-induced chemistry in reactive solids have led to the recognition of a new class of energetic materials which are unique in their response to shock waves. Experimental work has shown that chemical energy can be released on a time scale shorter than shock-transit times in laboratory samples. However, for many compositions, the reaction products remain in the condensed state upon release from high pressure, and no sudden expansion takes place. Nevertheless, if such a reaction is sufficiently rapid, it can be modeled as a type of detonation, termed ``heat detonation'' in the present paper. It is shown that unlike an explosive detonation, an unsupported heat detonation will decay to zero unless certain conditions are met. An example of such a reaction is Fe2 O3 +2Al+shock→Al2 O3 +2Fe (the standard thermite reaction). A shock-wave equation of state is determined from a mixture theory for reacted and unreacted porous thermite. The calculated shock temperatures are compared to experimentally measured shock temperatures, demonstrating that a shock-induced reaction takes place. Interpretation of the measured temperature history in the context of the thermochemical model implies that the principal rate-controlling kinetic mechanism is dynamic mixing at the shock front. Despite the similarity in thermochemical modeling of heat detonations to explosive detonations, the two processes are qualitatively very different in reaction mechanism as well as in the form the energy takes upon release, with explosives producing mostly work and heat detonations producing mostly heat.

  20. Hypothesis for synergistic toxicity of organophosphorus poisoning-induced cholinergic crisis and anaphylactoid reactions

    SciTech Connect

    Cowan, F.M.; Shih, T.M.; Lenz, D.E.; Madsen, J.M.; Broomfield, C.A.

    1996-08-01

    The neurotoxicity of organophosphorus (OP) compounds Involves the Inhibition of acetylchollnesterase (AChE), causing accumulation of acetyicholine (ACh) at synapses. However, cholinergic crisis may not be the sole mechanism of OP toxicity. Adverse drug reactions caused by synergistic toxicity between drugs with distinct pharmacological mechanisms are a common problem. Likewise, the multiple pharmacological activities of a single molecule might also contribute to either toxicity or efficacy. For example, certain OP compounds (e.g. soman) exhibit anti-AChE activity and also act as secretagogues by inducing mast cell degranulation with associated autacoid release and anaphylactoid reactions. Anaphylactoid shock can produce a lethal syndrome with symptoms of respiratory failure and circulatory collapse similar to the physiological sequelae observed for OP poisoning. Moreover, the major classes of drugs used as antidotes for OP intoxication can affect anaphylaxis. Acetylcholine can act as an agonist of autacoid release, and autacoids such as histamine can augment soman-Induced bronchial spasm. In concert with the demonstrably critical role of cholinergic crisis In OP toxicity, the precepts of neuroimmunology indicate that secondary adverse reactions encompassing anaphylactold reactions may complicate OP toxicity.

  1. A case of levocetirizine-induced fixed drug eruption and cross-reaction with piperazine derivatives

    PubMed Central

    Kim, Mi-Yeong; Jo, Eun-Jung; Chang, Yoon-Seok; Cho, Sang-Heon; Min, Kyung-Up

    2013-01-01

    Fixed drug eruption is an uncommon adverse drug reaction caused by delayed cell-mediated hypersensitivity. Levocetirizine is an active (R)-enatiomer of cetirizine and there have been a few reports of fixed drug eruption related to these antihistamines. We experienced a case of levocetirizine-induced fixed drug eruption and cross-reaction with other piperazine derivatives confirmed by patch test. A 73-year-old female patient presented with recurrent generalized itching, cutaneous bullae formation, rash and multiple pigmentation at fixed sites after taking drugs for common cold. She took bepotastine besilate (Talion®) and levocetirizine (Xyzal®) as antihistamine. She took acetaminophen, pseudoephedrine 60 mg / triprolidine 2.5 mg (Actifed®), dihydrocodeinebitartrate 5 mg / di-methylephedrine hydrochloride 17.5 mg / chlorpheniramine maleate 1.5 mg / guaifenesin 50 mg (Codening®) and aluminium hydroxide 200 mg / magnesium carbonate 120 mg (Antad®) at the same time. Patch test was done with suspected drugs and the result was positive with levocetirizine. We additionally performed patch test for other antihistamines such as cetirizine, hydroxyzine, fexofenadine and loratadine. Piperazine derivatives (cetirizine and hydroxyzine) were positive, but piperidine derivatives (fexofenadine and loratadine) were negative to patch test. There was no adverse drug reaction when she was challenged with fexofenadine. We report a case of levocetirizine-induced fixed drug eruption confirmed by patch test. Cross-reactions were only observed in the piperazine derivatives and piperidine antihistamine was tolerant to the patient. PMID:24260733

  2. Prevention and Management of Adverse Reactions Induced by Iodinated Contrast Media.

    PubMed

    Wu, Yi Wei; Leow, Kheng Song; Zhu, Yujin; Tan, Cher Heng

    2016-04-01

    Iodinated radiocontrast media (IRCM) is widely used in current clinical practice. Although IRCM is generally safe, serious adverse drug reactions (ADRs) may still occur. IRCM-induced ADRs may be subdivided into chemotoxic and hypersensitivity reactions. Several factors have been shown to be associated with an increased risk of ADRs, including previous contrast media reactions, history of asthma and allergic disease, etc. Contrast media with lower osmolality is generally recommended for at-risk patients to prevent ADRs. Current premedication prophylaxis in at-risk patients may reduce the risk of ADRs. However, there is still a lack of consensus on the prophylactic role of premedication. Contrast-induced nephropathy (CIN) is another component of IRCM-related ADRs. Hydration remains the mainstay of CIN prophylaxis in at-risk patients. Despite several preventive measures, ADRs may still occur. Treatment strategies for potential contrast reactions are also summarised in this article. This article summarises the pathophysiology, epidemiology and risk factors of ADRs with emphasis on prevention and treatment strategies. This will allow readers to understand the rationale behind appropriate patient preparation for diagnostic imaging involving IRCM.

  3. Heparin-induced thrombocytopenia: a review of concepts regarding a dangerous adverse drug reaction.

    PubMed

    Junqueira, Daniela Rezende Garcia; Carvalho, Maria das Graças; Perini, Edson

    2013-01-01

    Heparin is a natural agent with antithrombotic action, commercially available for therapeutic use as unfractionated heparin and low molecular weight heparin. Heparin-induced thrombocytopenia (HIT) is a serious adverse reaction to heparin that promotes antibody-mediated platelet activation. HIT is defined as a relative reduction in platelet count of 50% (even when the platelet count at its lowest level is above>150 x 10(9)/L) occurring within five to 14 days after initiation of the therapy. Thrombocytopenia is the main feature that directs the clinical suspicion of the reaction and the increased risk of thromboembolic complications is the most important and paradoxical consequence. The diagnosis is a delicate issue, and requires a combination of clinical probability and laboratory tests for the detection of platelet activation induced by HIT antibodies. The absolute risk of HIT has been estimated between 1% and 5% under treatment with unfractionated heparin, and less than 1% with low molecular weight heparin. However, high-quality evidence about the risk of HIT from randomized clinical trials is scarce. In addition, information on the frequency of HIT in developing countries is not widely available. This review aims to provide a better understanding of the key features of this reaction and updated information on its frequency to health professionals and other interested parties. Knowledge, familiarity, and access to therapeutic options for the treatment of this adverse reaction are mandatory to minimize the associated risks, improving patient safety.

  4. A case of levocetirizine-induced fixed drug eruption and cross-reaction with piperazine derivatives.

    PubMed

    Kim, Mi-Yeong; Jo, Eun-Jung; Chang, Yoon-Seok; Cho, Sang-Heon; Min, Kyung-Up; Kim, Sae-Hoon

    2013-10-01

    Fixed drug eruption is an uncommon adverse drug reaction caused by delayed cell-mediated hypersensitivity. Levocetirizine is an active (R)-enatiomer of cetirizine and there have been a few reports of fixed drug eruption related to these antihistamines. We experienced a case of levocetirizine-induced fixed drug eruption and cross-reaction with other piperazine derivatives confirmed by patch test. A 73-year-old female patient presented with recurrent generalized itching, cutaneous bullae formation, rash and multiple pigmentation at fixed sites after taking drugs for common cold. She took bepotastine besilate (Talion®) and levocetirizine (Xyzal®) as antihistamine. She took acetaminophen, pseudoephedrine 60 mg / triprolidine 2.5 mg (Actifed®), dihydrocodeinebitartrate 5 mg / di-methylephedrine hydrochloride 17.5 mg / chlorpheniramine maleate 1.5 mg / guaifenesin 50 mg (Codening®) and aluminium hydroxide 200 mg / magnesium carbonate 120 mg (Antad®) at the same time. Patch test was done with suspected drugs and the result was positive with levocetirizine. We additionally performed patch test for other antihistamines such as cetirizine, hydroxyzine, fexofenadine and loratadine. Piperazine derivatives (cetirizine and hydroxyzine) were positive, but piperidine derivatives (fexofenadine and loratadine) were negative to patch test. There was no adverse drug reaction when she was challenged with fexofenadine. We report a case of levocetirizine-induced fixed drug eruption confirmed by patch test. Cross-reactions were only observed in the piperazine derivatives and piperidine antihistamine was tolerant to the patient.

  5. Trehalose enhances osmotic tolerance and suppresses lysophosphatidylcholine-induced acrosome reaction in ram spermatozoon.

    PubMed

    Ahmad, E; Naseer, Z; Aksoy, M; Küçük, N; Uçan, U; Serin, I; Ceylan, A

    2015-09-01

    This study was aimed to investigate the influence of trehalose on osmotic tolerance and the ability of ram spermatozoon to undergo acrosome reaction induced by lysophosphatidylcholine (LPC). In experiment 1, the diluted ejaculates were exposed to anisosmotic fructose solutions (70, 500, 750 and 1000 mOsm l(-1) ) with or without 50 mm trehalose. The presence of trehalose in hyperosmotic conditions enhanced (P < 0.05) the percentage of live, live-intact and intact spermatozoa. Similarly, trehalose enhanced (P < 0.05) the live and live-intact spermatozoa during hypo-osmotic conditions. In experiment 2, the centrifuged ejaculates were diluted with TCG only or TCG containing either 50 or 100 mm trehalose. The acrosome reaction was induced by LPC. The percentage of acrosome-reacted spermatozoon was less (P < 0.05) in trehalose-supplemented groups compared to control. In experiment 3, the ejaculates were cryopreserved in an extender containing 0 mm (control), 50 mm or 100 mm trehalose. Supplementation of extender with trehalose, either 50 mm or 100 mm, enhanced the cryosurvival rate (P < 0.05) compared to the control. In conclusion, the presence of trehalose in anisosmotic conditions enhances the osmotic tolerance, cryosurvival rate of ram spermatozoon and suppresses their ability to undergo LPC and cryo-induced acrosome reaction.

  6. Analysis of the inflammatory reaction induced by the catfish (Cathorops spixii) venoms.

    PubMed

    Junqueira, Marcos Emerson Pinheiro; Grund, Lidiane Zito; Orii, Noêmia M; Saraiva, Tânia Cristina; de Magalhães Lopes, Carlos Alberto; Lima, Carla; Lopes-Ferreira, Mônica

    2007-06-01

    Cathorops spixii is one of the most abundant venomous fish of the southeastern coast of the State of São Paulo, and consequently causes a great part of the accidents seen there. The accidents affect mainly fishermen, swimmers and tourists and are characterized by punctiform or wide wounds, erythema, edema, pain, sudoresis, indisposition, fever, nausea, vomiting and secondary infection. The objective of this work was to characterize the inflammatory response induced in mice by both venoms (mucus and sting) of the catfish C. spixii. Our results demonstrated that both venoms induced a great number of rolling and adherent leukocytes in the post-capillary venules of cremaster muscle of mice, and an increase in the vascular permeability in peritoneal cavity. Mucus induced the recruitment of neutrophils immediately after injection followed later by macrophage infiltration. In contrast, the cellular infiltration elicited by sting venom was rapidly resolved. The peritonitis reaction provoked by venoms was characterized by cytokine (IL-6), chemokines (MCP-1 and KC) or lipid mediator (LTB4) production in the peritoneal cavity. The macrophages from 7-day mucus venom-induced exudates upon in vitro mucus venom stimulation, expressed CD11c x MHC class II and release bioactive IL-12p70. On the other hand, sting venom-elicited peritoneal macrophages lost the ability to differentiate into dendritic cells, following re-stimulation in vitro with sting venom, they do not express CD11c, nor do they exhibit sufficient levels of MHC class II. In conclusion, both types of venoms (mucus or sting) promote inflammatory reaction with different profiles, and the inflammatory reaction induced by the first was characterized by antigen persistence in peritoneal cavity that allowed the activation of phagocytic cells with capacity of antigenic presentation.

  7. CD32a antibodies induce thrombocytopenia and type II hypersensitivity reactions in FCGR2A mice.

    PubMed

    Meyer, Todd; Robles-Carrillo, Liza; Davila, Monica; Brodie, Meghan; Desai, Hina; Rivera-Amaya, Mildred; Francis, John L; Amirkhosravi, Ali

    2015-11-05

    The CD32a immunoglobulin G (IgG) receptor (Fcγ receptor IIa) is a potential therapeutic target for diseases in which IgG immune complexes (ICs) mediate inflammation, such as heparin-induced thrombocytopenia, rheumatoid arthritis, and systemic lupus erythematosus. Monoclonal antibodies (mAbs) are a promising strategy for treating such diseases. However, IV.3, perhaps the best characterized CD32a-blocking mAb, was recently shown to induce anaphylaxis in immunocompromised "3KO" mice. This anaphylactic reaction required a human CD32a transgene because mice lack an equivalent of this gene. The finding that IV.3 induces anaphylaxis in CD32a-transgenic mice was surprising because IV.3 had long been thought to lack the intrinsic capacity to trigger cellular activation via CD32a. Such an anaphylactic reaction would also limit potential therapeutic applications of IV.3. In the present study, we examine the molecular mechanisms by which IV.3 induces anaphylaxis. We now report that IV.3 induces anaphylaxis in immunocompetent CD32a-transgenic "FCGR2A" mice, along with the novel finding that IV.3 and 2 other well-characterized CD32a-blocking mAbs, AT-10 and MDE-8, also induce severe thrombocytopenia in FCGR2A mice. Using recombinant variants of these same mAbs, we show that IgG "Fc" effector function is necessary for the induction of anaphylaxis and thrombocytopenia in FCGR2A mice. Variants of these mAbs lacking the capacity to activate mouse IgG receptors not only failed to induce anaphylaxis or thrombocytopenia, but also very potently protected FCGR2A mice from near lethal doses of IgG ICs. Our findings show that effector-deficient IV.3, AT-10, and MDE-8 are promising candidates for developing therapeutic mAbs to treat CD32a-mediated diseases.

  8. Bond selectivity in electron-induced reaction due to directed recoil on an anisotropic substrate

    NASA Astrophysics Data System (ADS)

    Anggara, Kelvin; Huang, Kai; Leung, Lydie; Chatterjee, Avisek; Cheng, Fang; Polanyi, John C.

    2016-12-01

    Bond-selective reaction is central to heterogeneous catalysis. In heterogeneous catalysis, selectivity is found to depend on the chemical nature and morphology of the substrate. Here, however, we show a high degree of bond selectivity dependent only on adsorbate bond alignment. The system studied is the electron-induced reaction of meta-diiodobenzene physisorbed on Cu(110). Of the adsorbate's C-I bonds, C-I aligned `Along' the copper row dissociates in 99.3% of the cases giving surface reaction, whereas C-I bond aligned `Across' the rows dissociates in only 0.7% of the cases. A two-electronic-state molecular dynamics model attributes reaction to an initial transition to a repulsive state of an Along C-I, followed by directed recoil of C towards a Cu atom of the same row, forming C-Cu. A similar impulse on an Across C-I gives directed C that, moving across rows, does not encounter a Cu atom and hence exhibits markedly less reaction.

  9. Yield from Proton-Induced Reaction on Light Element Isotopes in the Hydrogen Plasma Focus

    NASA Astrophysics Data System (ADS)

    Udovičić, V.; Dragić, A.; Banjanac, R.; Joković, D.; Veselinović, N.; Aničin, I.; Savić, M.; Puzović, J.

    2011-12-01

    The high Q-value of some (p,α) fusion reactions is very important in the investigation that can lead to power production with controlled fusion using advanced fuels (hydrogen-lithium-7, hydrogen-boron-11). For this reason, it is crucial to know the rates of these fusion reactions. Unfortunately, in the fusion machines such as plasma focus device, the interaction energy is usually far below the Coulomb barrier. Because of that, direct measurements of the relevant reaction cross sections are practically impossible. A few different indirect approaches have been proposed. In this work the Trojan Horse Method (THM) will be described. On the basis of the results obtained from the THM method and data, which are well-known from our previous work (Banjanac et al. in Radiat Meas 40:483-485, 2005), the reaction rate for proton-induced reaction 7Li(p,α)α produced in the hydrogen plasma focus is calculated. This calculation will be compared with the measurements of α particles production rate using CR-39 detectors.

  10. One-two step transfer observed in 16O+11B nuclear system

    NASA Astrophysics Data System (ADS)

    Hamada, Sh.; Burtebayev, N.

    2015-06-01

    The angular distribution measurements for 16O ion beam elastically scattered from 11B target of thickness 32.9μg/cm2 at energy 22.4 MeV had been performed in the cyclotron DC-60 INP NNC RK. The previous measurements for 16O+11B nuclear system at energies 27, 30, 32.5 and 35 MeV showed an increase in the differential cross-section at backward angles due to the contribution of cluster transfer. Such transfer process could not be described in terms of optical model (OM); it could be described within the framework of distorted wave Born approximation method implemented in FRESCO code. Both one (5Li) and two-step transfer (proton transfer followed by Alpha transfer) were taken into considerations. We have extracted the spectroscopic amplitude (SA) for the configuration 16O→11B+5Li.

  11. The gamma 1 and gamma 3 bands of (16)O3: Line positions and intensities

    NASA Technical Reports Server (NTRS)

    Flaud, J.-M.; Camy-Peyret, C.; Devi, V. Malathy; Rinsland, C. P.; Smith, M. A. H.

    1988-01-01

    Using 0.005/cm-resolution Fourier transform spectra of samples of ozone, the gamma 1 and gamma 3 bands of (16)O3 have been reanalyzed to obtain accurate line positions and an extended set of upper state rotational levels (J up to 69, K sub a up to 20). Combined with the available microwave data, these upper state rotational levels were satisfactorily fitted using a Hamiltonian which takes explicitly into account the strong Coriolis interaction affecting the rotational levels of these two interacting states. In addition, 350 relative line intensities were measured from which the rotational expansions of the transition moment operators for the gamma 1 and gamma 3 states have been deduced. Finally, a complete listing of line positions, intensities, and lower state energies of the gamma 1 and gamma 3 bands of (16)O3 has been generated.

  12. Isotopic diversity in interplanetary dust particles and preservation of extreme 16O-depletion

    NASA Astrophysics Data System (ADS)

    Starkey, N. A.; Franchi, I. A.; Lee, M. R.

    2014-10-01

    Two interplanetary dust particles (IDPs) investigated by NanoSIMS reveal diverse oxygen isotope compositions at the micrometre-scale. The oxygen isotope values recorded at different locations across the single IDP fragments cover a wider range than the bulk values available from all IDPs and bulk meteorites measured to date. Measurement of H, C, and N isotopes by NanoSIMS, and the use of scanning and transmission electron microscopy (SEM and TEM) to determine elemental compositions and textural information allows for a better understanding of the lithologies and organic signatures associated with the oxygen isotope features. IDP Balmoral, a ∼15 μm-sized fragment with a chondritic porous (CP)-IDP-like texture, contains a region a few micrometres in size characterised by 16O-depleted isotope signatures in the range δ17O, δ18O = +80‰ to +200‰. The remainder of the fragment has a more 16O-rich composition (δ18O = 0-20‰), similar to many other IDPs and bulk meteorites. Other than in discrete pre-solar grains, such extreme 16O-depletions have only been observed previously in rare components within the matrix of the Acfer 094 meteorite. However, TEM imaging and FeO/MgO/Si ion ratios indicate that the 16O-depleted regions in Balmoral did not form by the same mechanism as that proposed for the 16O-depleted phases in Acfer 094. As the level of 16O depletion is consistent with that expected from isotope selective self-shielding, it is likely that the 16O-depleted reservoir was located close to that where oxygen self-shielding effects were most pronounced (i.e., the outer solar nebula or even interstellar medium). Individual regions within IDP Lumley cover a range in δ18O from -30‰ to +19‰, with the oxygen isotope values broadly co-varying with δD, δ13C, δ15N, light-element ratios and texture. The relationships observed in Lumley indicate that the parent body incorporated material at the micrometre-scale from discrete diverse isotopic reservoirs, some of

  13. Sub-Doppler Measurements of the Rotational Spectrum of (13)C(16)O.

    PubMed

    Klapper; Lewen; Gendriesch; Belov; Winnewisser

    2000-05-01

    The five lowest J rotational transitions of (13)C(16)O have been measured by saturation-dip spectroscopy to an accuracy of about 2 kHz, employing phase-stabilized backward-wave oscillators (BWOs). These highly precise measurements cover the transitions from J = 2 <-- 1 to J = 6 <-- 5 with frequencies ranging from 220 to 661 GHz. For each of the five observed rotational transitions, the narrow linewidths of the saturation dips (about 20 kHz) permitted the resolution of the hyperfine splitting for the first time. This splitting is caused by the (13)C-nuclear spin-rotation interaction yielding a value for the nuclear spin-rotation coupling constant of C(I)((13)C(16)O). If combined with the beam measurements (C(I)((13)C(16)O) = 32.63(10) kHz), a slight J-dependence of the spin-rotation coupling constant can be determined (C(J) = 30 +/- 13 Hz). In addition, we have measured in the Doppler-limited mode several higher J rotational line positions of (13)C(16)O up to 991 GHz with an accuracy of 5 kHz. The two line positions (J = 12 <-- 11 and J = 14 <-- 13) were recorded by multiplying BWO frequency with an accuracy of 100 kHz. The rotational transitions J = 17 <-- 16 and J = 18 <-- 17 were measured with an accuracy between 15 and 25 kHz by using the Cologne sideband spectrometer for terahertz applications COSSTA. Copyright 2000 Academic Press.

  14. Prediction of enhanced solvent-induced enantioselectivity for a ring opening with a bifurcating reaction path

    DOE PAGES

    Carpenter, Barry K.; Harvey, Jeremy N.; Glowacki, David R.

    2014-12-11

    Classical molecular dynamics simulations are reported for the deazetisation and ring opening of meso-2,3-difluoro-2,3-dimethyldiazocyclopropane in three solvents: CHCl3, CHFClBr and CH3CH(OH)CF3 (TFIPA). In this study, the achiral reactant leads to enantiomeric allene products, and the question addressed in the study is whether either of the chiral, enantiomerically pure solvents can induce significant enantiomeric excess in the products. The direct dynamics calculations use an empirical valence bond potential for the solute, with empirical parameters optimised against M06-2X/cc-pVTZ density functional results. The results reveal that the exothermic N2 loss and ring opening promote transient strong solvent–solute interactions within the first ~100 fsmore » of the reaction. Because of the bifurcating reaction path, these interactions occur at time when the “decision” about which enantiomer of the product to form has yet to be made (at least for many of the trajectories). Hence, it is possible in principle that the solvent could exert a larger-than-normal influence on the course of the reaction. In fact, the results reveal no such effect for CHFClBr but do predict that TFIPA should induce 15.2 ± 2.1% enantiomeric excess. This is roughly an order of magnitude larger than solvent-induced enantiomeric excesses found experimentally in reactions where the conversion of reactant(s) to enantiomeric products occur over separate transition states.« less

  15. Prediction of enhanced solvent-induced enantioselectivity for a ring opening with a bifurcating reaction path

    SciTech Connect

    Carpenter, Barry K.; Harvey, Jeremy N.; Glowacki, David R.

    2014-12-11

    Classical molecular dynamics simulations are reported for the deazetisation and ring opening of meso-2,3-difluoro-2,3-dimethyldiazocyclopropane in three solvents: CHCl3, CHFClBr and CH3CH(OH)CF3 (TFIPA). In this study, the achiral reactant leads to enantiomeric allene products, and the question addressed in the study is whether either of the chiral, enantiomerically pure solvents can induce significant enantiomeric excess in the products. The direct dynamics calculations use an empirical valence bond potential for the solute, with empirical parameters optimised against M06-2X/cc-pVTZ density functional results. The results reveal that the exothermic N2 loss and ring opening promote transient strong solvent–solute interactions within the first ~100 fs of the reaction. Because of the bifurcating reaction path, these interactions occur at time when the “decision” about which enantiomer of the product to form has yet to be made (at least for many of the trajectories). Hence, it is possible in principle that the solvent could exert a larger-than-normal influence on the course of the reaction. In fact, the results reveal no such effect for CHFClBr but do predict that TFIPA should induce 15.2 ± 2.1% enantiomeric excess. This is roughly an order of magnitude larger than solvent-induced enantiomeric excesses found experimentally in reactions where the conversion of reactant(s) to enantiomeric products occur over separate transition states.

  16. Oxidation of elemental mercury by chlorine: Gas phase, Surface,and Photo-induced reaction pathways

    SciTech Connect

    Yan, Nai-Qiang; Liu, Shou-Heng; Chang, Shih-Ger

    2004-10-22

    Accurate oxidation rate constants of mercury gas are needed for determining its dispersion and lifetime in the atmosphere. They would also help in developing a technology for the control of mercury emissions from coal-fired power plants. However, it is difficult to establish the accurate rate constants primarily due to the fact that mercury easily adsorbs on solid surface and its reactions can be catalyzed by the surface. We have demonstrated a procedure that allows the determination of gas phase, surface-induced, and photo-induced contributions in the kinetic study of the oxidation of mercury by chlorine gas. The kinetics was studied using reactors with various surface to volume ratios. The effect of the surface and the photo irradiation on the reaction was taken into consideration. The pressure dependent study revealed that the gas phase oxidation was a three-body collision process. The third order rate constant was determined to be 7.5({+-}0.2) x 10{sup -39} mL{sup 2} molecules{sup -2}s{sup -1} with N{sub 2} as the third body at 297 {+-} 1 K. The surface induced reaction on quartz window was second order and the rate constant was 2.7 x 10{sup -17} mL{sup 2} molecules{sup -1} cm{sup -2} sec. Meanwhile, the 253.7 nm photon employed for mercury detection was found to accelerate the reaction. The utilization efficiency of 253.7 nm photon for Hg{sup 0} oxidation was 6.7 x 10{sup -4} molecules photon{sup -1} under the conditions employed in this study.

  17. Purification of Nanoscale Electron-Beam-Induced Platinum Deposits via a Pulsed Laser-Induced Oxidation Reaction

    DOE PAGES

    Stanford, Michael G.; Lewis, Brett B.; Noh, Joo Hyon; ...

    2014-11-05

    Platinum–carbon deposits made via electron-beam-induced deposition were purified in this study via a pulsed laser-induced oxidation reaction and erosion of the amorphous carbon to form pure platinum. Purification proceeds from the top down and is likely catalytically facilitated via the evolving platinum layer. Thermal simulations suggest a temperature threshold of ~485 K, and the purification rate is a function of the PtC5 thickness (80–360 nm) and laser pulse width (1–100 μs) in the ranges studied. The thickness dependence is attributed to the ~235 nm penetration depth of the PtC5 composite at the laser wavelength, and the pulse-width dependence is attributedmore » to the increased temperatures achieved at longer pulse widths. Finally, remarkably fast purification is realized at cumulative laser exposure times of less than 1 s.« less

  18. Purification of Nanoscale Electron-Beam-Induced Platinum Deposits via a Pulsed Laser-Induced Oxidation Reaction

    SciTech Connect

    Stanford, Michael G.; Lewis, Brett B.; Noh, Joo Hyon; Fowlkes, Jason Davidson; Roberts, Nicholas A.; Plank, Harald; Rack, Philip D.

    2014-11-05

    Platinum–carbon deposits made via electron-beam-induced deposition were purified in this study via a pulsed laser-induced oxidation reaction and erosion of the amorphous carbon to form pure platinum. Purification proceeds from the top down and is likely catalytically facilitated via the evolving platinum layer. Thermal simulations suggest a temperature threshold of ~485 K, and the purification rate is a function of the PtC5 thickness (80–360 nm) and laser pulse width (1–100 μs) in the ranges studied. The thickness dependence is attributed to the ~235 nm penetration depth of the PtC5 composite at the laser wavelength, and the pulse-width dependence is attributed to the increased temperatures achieved at longer pulse widths. Finally, remarkably fast purification is realized at cumulative laser exposure times of less than 1 s.

  19. Drug Reaction With Eosinophilia and Systemic Symptoms Induced by Valproic Acid: A Case Report

    PubMed Central

    Darban, Mahboubeh; Bagheri, Bahador

    2016-01-01

    Introduction Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a rare but life-threatening reaction to drugs such as carbamazepine and allopurinol. The condition is characterized by skin rashes, fever, hematological disturbances, lymphadenopathy, and organ failure, most probably hepatic dysfunction. To date, only a few cases of valproate-induced DRESS syndrome have been reported. Case Presentation We report on the case of a 60-year-old man who had been treated with valproic acid some time before being referred to Kowsar Hospital, Semnan, Iran in December 2015. He was given valproic acid 1000 mg PO, and after 20 days, he had developed widespread rashes, fever, esophagitis, cervical lymphadenopathy, and tender hepatomegaly. Laboratory results at Kowsar showed a drop in hemoglobin, in addition to lymphocytosis, thrombocytopenia, and elevated serum transaminases. DRESS was diagnosed, and corticosteroid therapy was initiated. Administration of the culprit drug to the patient was also stopped. Intravenous immunoglobulin (IVIG) improved the general condition of the patient. Conclusions Only a small number of case reports have described valproic acid-induced DRESS syndrome; therefore, the condition is difficult to prevent. Rechallenge with valproic acid should be avoided in patients with a history of reaction to the drug. PMID:28144463

  20. Investigation of the α-particle induced nuclear reactions on natural molybdenum

    NASA Astrophysics Data System (ADS)

    Ditrói, F.; Hermanne, A.; Tárkányi, F.; Takács, S.; Ignatyuk, A. V.

    2012-08-01

    Cross-sections of alpha particle induced nuclear reactions on natural molybdenum have been studied in the frame of a systematic investigation of charged particle induced nuclear reactions on metals for different applications. The excitation functions of 93mTc, 93gTc(m+), 94mTc, 94gTc, 95mTc, 95gTc, 96gTc(m+), 99mTc, 93mMo, 99Mo(cum), 90Nb(m+), 94Ru, 95Ru,97Ru, 103Ru and 88Zr were measured up to 40 MeV alpha energy by using a stacked foil technique and activation method. The main goals of this work were to get experimental data for accelerator technology, for monitoring of alpha beam, for thin layer activation technique and for testing nuclear reaction theories. The experimental data were compared with critically analyzed published data and with the results of model calculations, obtained by using the ALICE-IPPE, EMPIRE and TALYS codes (TENDL-2011).

  1. Feeding of Rh and Ag isomers in fast-neutron-induced reactions

    DOE PAGES

    Fotiades, Nikolaos; Devlin, Matthew James; Nelson, Ronald Owen; ...

    2016-10-17

    In (n,n') reactions on stable Ir and Au isotopes in the mass A=190 region, the experimentally established feeding of the isomers relative to the feeding of the corresponding ground states increases with increasing neutron energy, up to the neutron energy where the (n,2n) reaction channel opens up, and then decreases. In order to check for similar behavior in the mass A=100 region, the feeding of isomers and ground states in fast-neutron-induced reactions on stable isotopes in this mass region was studied. This is of especial interest for Rh which can be used as a radiochemical detector. Here, excited states weremore » studied using the (n,n'γ), (n,2nγ), and (n,3nγ) reactions on 103Rh and 109Ag. A germanium detector array for γ-ray detection and the broad-spectrum pulsed neutron source of the Los Alamos Neutron Science Center's Weapons Neutron Research facility were used for the measurement. The energy of the incident neutrons was determined using the time-of-flight technique. Absolute partial γ-ray cross sections were measured for 57 transitions feeding isomers and ground states in 101,102,103Rh and 107,108,109Ag. The feeding of the isomers was found to be very similar in the corresponding reaction channels and it is compared to the feeding determined for the ground states. In conclusion, the opening of reaction channels at higher neutron energies removes angular momentum from the residual nucleus and reduces the population of the higher-spin isomers relative to the feeding of the lower-spin ground states. Similar behavior was observed in the mass A=190 region in the feeding of higher-spin isomers, but the reverse behavior was observed in 176Lu with a lower-spin isomer and a higher-spin ground state.« less

  2. Feeding of Rh and Ag isomers in fast-neutron-induced reactions

    NASA Astrophysics Data System (ADS)

    Fotiades, N.; Devlin, M.; Nelson, R. O.; Kawano, T.; Carroll, J. J.

    2016-10-01

    Background: In (n ,n' ) reactions on stable Ir and Au isotopes in the mass A =190 region, the experimentally established feeding of the isomers relative to the feeding of the corresponding ground states increases with increasing neutron energy, up to the neutron energy where the (n ,2 n ) reaction channel opens up, and then decreases. Purpose: In order to check for similar behavior in the mass A =100 region, the feeding of isomers and ground states in fast-neutron-induced reactions on stable isotopes in this mass region was studied. This is of especial interest for Rh which can be used as a radiochemical detector. Methods: Excited states were studied using the (n ,n'γ ), (n ,2 n γ ), and (n ,3 n γ ) reactions on 103Rh and 109Ag. A germanium detector array for γ -ray detection and the broad-spectrum pulsed neutron source of the Los Alamos Neutron Science Center's Weapons Neutron Research facility were used for the measurement. The energy of the incident neutrons was determined using the time-of-flight technique. Results: Absolute partial γ -ray cross sections were measured for 57 transitions feeding isomers and ground states in 101,102,103Rh and 107,108,109Ag. The feeding of the isomers was found to be very similar in the corresponding reaction channels and it is compared to the feeding determined for the ground states. Conclusions: The opening of reaction channels at higher neutron energies removes angular momentum from the residual nucleus and reduces the population of the higher-spin isomers relative to the feeding of the lower-spin ground states. Similar behavior was observed in the mass A =190 region in the feeding of higher-spin isomers, but the reverse behavior was observed in 176Lu with a lower-spin isomer and a higher-spin ground state.

  3. Feeding of Rh and Ag isomers in fast-neutron-induced reactions

    SciTech Connect

    Fotiades, Nikolaos; Devlin, Matthew James; Nelson, Ronald Owen; Kawano, T.; Carroll, J. J.

    2016-10-17

    In (n,n') reactions on stable Ir and Au isotopes in the mass A=190 region, the experimentally established feeding of the isomers relative to the feeding of the corresponding ground states increases with increasing neutron energy, up to the neutron energy where the (n,2n) reaction channel opens up, and then decreases. In order to check for similar behavior in the mass A=100 region, the feeding of isomers and ground states in fast-neutron-induced reactions on stable isotopes in this mass region was studied. This is of especial interest for Rh which can be used as a radiochemical detector. Here, excited states were studied using the (n,n'γ), (n,2nγ), and (n,3nγ) reactions on 103Rh and 109Ag. A germanium detector array for γ-ray detection and the broad-spectrum pulsed neutron source of the Los Alamos Neutron Science Center's Weapons Neutron Research facility were used for the measurement. The energy of the incident neutrons was determined using the time-of-flight technique. Absolute partial γ-ray cross sections were measured for 57 transitions feeding isomers and ground states in 101,102,103Rh and 107,108,109Ag. The feeding of the isomers was found to be very similar in the corresponding reaction channels and it is compared to the feeding determined for the ground states. In conclusion, the opening of reaction channels at higher neutron energies removes angular momentum from the residual nucleus and reduces the population of the higher-spin isomers relative to the feeding of the lower-spin ground states. Similar behavior was observed in the mass A=190 region in the feeding of higher-spin isomers, but the reverse behavior was observed in 176Lu with a lower-spin isomer and a higher-spin ground state.

  4. Drug-induced anaphylactic reactions in Indian population: A systematic review

    PubMed Central

    Patel, Tejas K.; Patel, Parvati B.; Barvaliya, Manish J.; Tripathi, C. B.

    2014-01-01

    Background: Epidemiological data on drug-induced anaphylactic reactions are limited in India and are largely depending on studies from developed countries. Aim: The aim was to analyze the published studies of drug-induced anaphylaxis reported from India in relation with causative drugs and other clinical characteristics. Materials and Methods: The electronic databases were searched for Indian publications from 1998 to 2013 describing anaphylactic reactions. The information was collected for demographics, set up in which anaphylaxis occurred, causative drugs, incubation period, clinical features, associated allergic conditions, past reactions, co-morbid conditions, skin testing, IgE assays, therapeutic intervention and mortality. Reactions were analyzed for severity, causality, and preventability. Data were extracted and summarized by absolute numbers, mean (95% confidence interval [CI]), percentages and odds ratio (OR) (95% CI). Results: From 3839 retrieved references, 52 references describing 54 reactions were included. The mean age was 35.31 (95% CI: 30.52–40.10) years. Total female patients were 61.11%. Majority reactions were developed in perioperative conditions (53.70%), ward (20.37%) and home (11.11%). The major incriminated groups were antimicrobials (18.52%), nonsteroidal antiinflammatory drugs-(NSAIDs) (12.96%) and neuromuscular blockers (12.96%). Common causative drugs were diclofenac (11.11%), atracurium (7.41%) and β-lactams (5.96%). Cardiovascular (98.15%) and respiratory (81.48%) symptoms dominated the presentation. Skin tests and IgE assays were performed in 37.03% and 18.52% cases, respectively. The fatal cases were associated with complications (OR =5.04; 95% CI: 1.41–17.92), cerebral hypoxic damage (OR =6.80; 95% CI: 2.14–21.58) and preventable reactions (OR =14.33; 95% CI: 2.33–87.97). Conclusion: Antimicrobials, NSAIDs, and neuromuscular blockers are common causative groups. The most fatal cases can be prevented by avoiding allergen

  5. Age and size at maturity: a quantitative review of diet-induced reaction norms in insects.

    PubMed

    Teder, Tiit; Vellau, Helen; Tammaru, Toomas

    2014-11-01

    Optimality models predict that diet-induced bivariate reaction norms for age and size at maturity can have diverse shapes, with the slope varying from negative to positive. To evaluate these predictions, we perform a quantitative review of relevant data, using a literature-derived database of body sizes and development times for over 200 insect species. We show that bivariate reaction norms with a negative slope prevail in nearly all taxonomic and ecological categories of insects as well as in some other ectotherm taxa with comparable life histories (arachnids and amphibians). In insects, positive slopes are largely limited to species, which feed on discrete resource items, parasitoids in particular. By contrast, with virtually no meaningful exceptions, herbivorous and predatory insects display reaction norms with a negative slope. This is consistent with the idea that predictable resource depletion, a scenario selecting for positively sloped reaction norms, is not frequent for these insects. Another source of such selection-a positive correlation between resource levels and juvenile mortality rates-should similarly be rare among insects. Positive slopes can also be predicted by models which integrate life-history evolution and population dynamics. As bottom-up regulation is not common in most insect groups, such models may not be most appropriate for insects.

  6. Microscopic dynamics simulations of heavy-ion fusion reactions induced by neutron-rich nuclei

    NASA Astrophysics Data System (ADS)

    Wang, Ning; Ou, Li; Zhang, Yingxun; Li, Zhuxia

    2014-06-01

    The heavy-ion fusion reactions induced by neutron-rich nuclei are investigated with the improved quantum molecular dynamics (ImQMD) model. With a subtle consideration of the neutron skin thickness of nuclei and the symmetry potential, the stability of nuclei and the fusion excitation functions of heavy-ion fusion reactions O16 + Ge76, O16 + Sm154, Ca40 + Zr96, and Sn132 + Ca40 are systematically studied. The fusion cross sections of these reactions at energies around the Coulomb barrier can be well reproduced by using the ImQMD model. The corresponding slope parameter of the symmetry energy adopted in the calculations is L ≈78 MeV and the surface energy coefficient is gsur=18±1.5 MeV fm2. In addition, it is found that the surface-symmetry term significantly influences the fusion cross sections of neutron-rich fusion systems. For sub-barrier fusion, the dynamical fluctuations in the densities of the reaction partners and the enhanced surface diffuseness at neck side result in the lowering of the fusion barrier.

  7. Lipoic acid suppresses compound 48/80-induced anaphylaxis-like reaction

    PubMed Central

    Choi, Yun Ho; Chai, Ok Hee; Han, Eui-Hyeog; Choi, Su-Young; Kim, Hyoung Tae

    2010-01-01

    Alpha-lipoic acid (LA), a naturally occurring dithiol compound, is an essential cofactor in metabolic reactions involved in energy utilization. LA improves glycemic control, reduces diabetic polyneuropathies, atherosclerosis, and allergic inflammation. The effects of LA on mast cell-mediated anaphylactic reactions, however, are unknown. LA dose-dependently inhibited systemic and passive cutaneous anaphylaxis-like reactions in mice induced by compound 48/80, a condensation product of N-methyl-p-methoxyphenethylamine and formaldehyde. Pretreatment with LA, prior to induction of the systemic anaphylaxis-like reaction with compound 48/80, reduced plasma histamine levels in a dose-dependent manner. In our in vitro study, LA decreased histamine release from rat peritoneal mast cells (RPMCs) triggered by compound 48/80. Moreover, an increase in calcium uptake activated by compound 48/80 was inhibited by LA. LA also significantly elevated intracellular cyclic adenosine-3',5' monophosphate (cAMP) levels in RPMCs. This inhibition of mediator release from RPMCs may be due to inhibition of calcium uptake and augmentation of intracellular cAMP levels. Based on these results, we suggest that LA may be a potential remedy for allergy-related diseases. PMID:21267406

  8. Polycaprolactone nanofibrous mesh reduces foreign body reaction and induces adipose flap expansion in tissue engineering chamber

    PubMed Central

    Luo, Lin; He, Yunfan; Chang, Qiang; Xie, Gan; Zhan, Weiqing; Wang, Xuecen; Zhou, Tao; Xing, Malcolm; Lu, Feng

    2016-01-01

    Tissue engineering chamber technique can be used to generate engineered adipose tissue, showing the potential for the reconstruction of soft tissue defects. However, the consequent foreign body reaction induced by the exogenous chamber implantation causes thick capsule formation on the surface of the adipose flap following capsule contracture, which may limit the internal tissue expansion. The nanotopographical property and architecture of nanofibrous scaffold may serve as a promising method for minimizing the foreign body reaction. Accordingly, electrospinning porous polycaprolactone (PCL) nanofibrous mesh, a biocompatible synthetic polymer, was attached to the internal surface of the chamber for the reducing local foreign body reaction. Adipose flap volume, level of inflammation, collagen quantification, capsule thickness, and adipose tissue-specific gene expression in chamber after implantation were evaluated at different time points. The in vivo study revealed that the engineered adipose flaps in the PCL group had a structure similar to that in the controls and normal adipose tissue structure but with a larger flap volume. Interleukin (IL)-1β, IL-6, and transforming growth factor-β expression decreased significantly in the PCL group compared with the control. Moreover, the control group had much more collagen deposition and thicker capsule than that observed in the PCL group. These results indicate that the unique nanotopographical effect of electrospinning PCL nanofiber can reduce foreign body reaction in a tissue engineering chamber, which maybe a promising new method for generating a larger volume of mature, vascularized, and stable adipose tissue. PMID:27980405

  9. Exploiting Photo-induced Reactions in Polymer Blends to Create Hierarchically Ordered, Defect-free Materials

    ScienceCinema

    Balazs, Anna [University of Pittsburgh, Pittsburgh, Pennsylvania, United States

    2016-07-12

    Computer simulations reveal how photo-induced chemical reactions can be exploited to create long-range order in binary and ternary polymeric materials. The process is initiated by shining a spatially uniform light over a photosensitive AB binary blend, which undergoes both a reversible chemical reaction and phase separation. We then introduce a well-collimated, higher-intensity light source. Rastering this secondary light over the sample locally increases the reaction rate and causes formation of defect-free, spatially periodic structures. These binary structures resemble either the lamellar or hexagonal phases of microphase-separated di-block copolymers. We measure the regularity of the ordered structures as a function of the relative reaction rates for different values of the rastering speed and determine the optimal conditions for creating defect-free structures in the binary systems. We then add a non-reactive homo-polymer C, which is immiscible with both A and B. We show that this component migrates to regions that are illuminated by the secondary, higher-intensity light, allowing us to effectively write a pattern of C onto the AB film. Rastering over the ternary blend with this collimated light now leads to hierarchically ordered patterns of A, B, and C. The findings point to a facile, non-intrusive process for manufacturing high-quality polymeric devices in a low-cost, efficient manner.

  10. The use of low energy, ion induced nuclear reactions for proton radiotherapy applications

    SciTech Connect

    Horn, K.M.; Doyle, B.; Segal, M.N.; Hamm, R.W.; Adler, R.J.; Glatstein, E.

    1995-04-01

    Medical radiotherapy has traditionally relied upon the use of external photon beams and internally implanted radioisotopes as the chief means of irradiating tumors. However, advances in accelerator technology and the exploitation of novel means of producing radiation may provide useful alternatives to some current modes of medical radiation delivery with reduced total dose to surrounding healthy tissue, reduced expense, or increased treatment accessibility. This paper will briefly overview currently established modes of radiation therapy, techniques still considered experimental but in clinical use, innovative concepts under study that may enable new forms of treatment or enhance existing ones. The potential role of low energy, ion-induced nuclear reactions in radiotherapy applications is examined specifically for the 650 keV d({sup 3}He,p){sup 4}He nuclear reaction. This examination will describe the basic physics associated with this reaction`s production of 17.4 MeV protons and the processes used to fabricate the necessary materials used in the technique. Calculations of the delivered radiation dose, heat generation, and required exposure times are presented. Experimental data are also presented validating the dose calculations. The design of small, lower cost ion accelerators, as embodied in `nested`-tandem and radio frequency quadrupole accelerators is examined, as is the potential use of high-output {sup 3}He and deuterium ion sources. Finally, potential clinical applications are discussed in terms of the advantages and disadvantages of this technique with respect to current radiotherapy methods and equipment.

  11. Structural study of the X-ray-induced enzymatic reaction of octahaem cytochrome C nitrite reductase.

    PubMed

    Trofimov, A A; Polyakov, K M; Lazarenko, V A; Popov, A N; Tikhonova, T V; Tikhonov, A V; Popov, V O

    2015-05-01

    Octahaem cytochrome c nitrite reductase from the bacterium Thioalkalivibrio nitratireducens catalyzes the reduction of nitrite to ammonium and of sulfite to sulfide. The reducing properties of X-ray radiation and the high quality of the enzyme crystals allow study of the catalytic reaction of cytochrome c nitrite reductase directly in a crystal of the enzyme, with the reaction being induced by X-rays. Series of diffraction data sets with increasing absorbed dose were collected from crystals of the free form of the enzyme and its complexes with nitrite and sulfite. The corresponding structures revealed gradual changes associated with the reduction of the catalytic haems by X-rays. In the case of the nitrite complex the conversion of the nitrite ions bound in the active sites to NO species was observed, which is the beginning of the catalytic reaction. For the free form, an increase in the distance between the oxygen ligand bound to the catalytic haem and the iron ion of the haem took place. In the case of the sulfite complex no enzymatic reaction was detected, but there were changes in the arrangement of the active-site water molecules that were presumably associated with a change in the protonation state of the sulfite ions.

  12. Low energy electron induced reactions in fluorinated acetamide - probing negative ions and neutral stable counterparts*

    NASA Astrophysics Data System (ADS)

    Kopyra, Janina; König-Lehmann, Constanze; Illenberger, Eugen; Warneke, Jonas; Swiderek, Petra

    2016-06-01

    Electron impact to trifluoroacetamide (CF3CONH2, TFAA) in the energy range 0-12 eV leads to a variety of negative fragment ions which are formed via dissociative electron attachment (DEA). The underlying reactions range from single bond cleavages to remarkably complex reactions that lead to loss of the neutral units HF, H2O and HNCO as deduced from their directly observed ionic counterparts (M - H2O)-, (M - HF)- and (M - HNCO)-. Also formed are the pseudo-halogen ions CN- and OCN-. All these reactions proceed dominantly via a resonance located near 1 eV, i.e., electrons at subexcitation energies trigger reactions involving multiple bond cleavages. The electron induced generation of the neutral molecules HF, H2O and HNCO in condensed TFAA films is probed by temperature controlled thermal desorption spectrometry (TDS) which can be viewed as a complementary techniques to gas-phase experiments in DEA to directly probe the neutral counterparts. Contribution to the Topical Issue "Advances in Positron and Electron Scattering", edited by Paulo Limao-Vieira, Gustavo Garcia, E. Krishnakumar, James Sullivan, Hajime Tanuma and Zoran Petrovic.

  13. [EEG changes and stress reactions in rat induced by millimeter wave].

    PubMed

    Xie, Taorong; Pei, Jian; Li, Fen; Huang, Xin; Chen, Shude; Qiao, Dengjiang

    2011-02-01

    The present paper is aimed to study the processes of stress reaction and their judgment bases in rat induced by 35 GHz millimeter wave quantitatively. The relative change in the average energy of each EEG frequency band decomposed by wavelet analysis was calculated for extracting the stress indicator for the purpose. The rat would experience quiet period, guarding period, deadlock period and prostrating period in sequence. The judgment bases of different stress periods in rat induced by millimeter wave were obtained by analyzing the skin temperature, skin injury and changes of blood biochemical indexes during each stress period. The stress period changed from quiet period to guarding period when the skin temperature of irradiated area reached the thermal pain threshold. It was from guarding period to deadlock period when the skin had gotten serious injury. Then the rat reaction sensitivity decreased, and injury of its visceral organs occurred. The rat got to prostrating period when the sustained irradiation caused the rat's visceral organs to get more serious injury. The further sustained irradiation finally induced death of the rat.

  14. Shear-induced reaction-limited aggregation kinetics of brownian particles at arbitrary concentrations.

    PubMed

    Zaccone, Alessio; Gentili, Daniele; Wu, Hua; Morbidelli, Massimo

    2010-04-07

    The aggregation of interacting brownian particles in sheared concentrated suspensions is an important issue in colloid and soft matter science per se. Also, it serves as a model to understand biochemical reactions occurring in vivo where both crowding and shear play an important role. We present an effective medium approach within the Smoluchowski equation with shear which allows one to calculate the encounter kinetics through a potential barrier under shear at arbitrary colloid concentrations. Experiments on a model colloidal system in simple shear flow support the validity of the model in the concentration range considered. By generalizing Kramers' rate theory to the presence of shear and collective hydrodynamics, our model explains the significant increase in the shear-induced reaction-limited aggregation kinetics upon increasing the colloid concentration.

  15. Force-induced chemical reactions on the metal centre in a single metalloprotein molecule.

    PubMed

    Zheng, Peng; Arantes, Guilherme M; Field, Martin J; Li, Hongbin

    2015-06-25

    Metalloproteins play indispensable roles in biology owing to the versatile chemical reactivity of metal centres. However, studying their reactivity in many metalloproteins is challenging, as protein three-dimensional structure encloses labile metal centres, thus limiting their access to reactants and impeding direct measurements. Here we demonstrate the use of single-molecule atomic force microscopy to induce partial unfolding to expose metal centres in metalloproteins to aqueous solution, thus allowing for studying their chemical reactivity in aqueous solution for the first time. As a proof-of-principle, we demonstrate two chemical reactions for the FeS4 centre in rubredoxin: electrophilic protonation and nucleophilic ligand substitution. Our results show that protonation and ligand substitution result in mechanical destabilization of the FeS4 centre. Quantum chemical calculations corroborated experimental results and revealed detailed reaction mechanisms. We anticipate that this novel approach will provide insights into chemical reactivity of metal centres in metalloproteins under biologically more relevant conditions.

  16. Drug Reaction with Eosinophilia and Systemic Symptom Syndrome Induced by Lamotrigine

    PubMed Central

    Han, Song Hee; Hur, Min Seok; Youn, Hae Jeong; Roh, Nam Kyung; Lee, Yang Won; Choe, Yong Beom

    2017-01-01

    Drug reaction with eosinophilia and systemic symptom (DRESS) syndrome is a type of severe adverse drug-induced reaction. Dermatologists should make a quick diagnosis and provide appropriate treatment for DRESS syndrome to reduce mortality rates, which can be as high as 10%. We present the case of a 47-year-old man with schizoaffective disorder treated with lamotrigine who developed DRESS syndrome to emphasize the importance of close observation of patients with drug eruption. He was consulted for erythematous maculopapular rashes on the trunk that developed 3 weeks after starting lamotrigine. A few days later, he developed generalized influenza-like symptoms. The skin rashes spread over his entire body, and the sense of itching was rapidly aggravated within a few days. Increased liver enzyme levels and significant eosinophilia were found on laboratory test results. His condition was diagnosed as DRESS syndrome, and he was treated with systemic and topical corticosteroids for 2 weeks.

  17. Nuclear fragmentation and charge-exchange reactions induced by pions in the Δ -resonance region

    NASA Astrophysics Data System (ADS)

    Feng, Zhao-Qing

    2016-11-01

    The dynamics of the nuclear fragmentations and the charge exchange reactions in pion-nucleus collisions near the Δ (1232) resonance energies has been investigated within the Lanzhou quantum molecular dynamics transport model. An isospin-, momentum-, and density-dependent pion-nucleon potential is implemented in the model, which influences the pion dynamics, in particular the kinetic energy spectra, but weakly impacts the fragmentation mechanism. The absorption process in pion-nucleon collisions to form the Δ (1232) resonance dominates the heating mechanism of the target nucleus. The excitation energy transferred to the target nucleus increases with the pion kinetic energy and is similar for both π-- and π+-induced reactions. The magnitude of fragmentation of the target nucleus weakly depends on the pion energy. The isospin ratio in the pion double-charge exchange is influenced by the isospin ingredient of target nucleus.

  18. Statistical model analysis of α -induced reaction cross sections of 64Zn at low energies

    NASA Astrophysics Data System (ADS)

    Mohr, P.; Gyürky, Gy.; Fülöp, Zs.

    2017-01-01

    Background: α -nucleus potentials play an essential role in the calculation of α -induced reaction cross sections at low energies in the statistical model. Uncertainties of these calculations are related to ambiguities in the adjustment of the potential parameters to experimental elastic scattering angular distributions (typically at higher energies) and to the energy dependence of the effective α -nucleus potentials. Purpose: The present work studies cross sections of α -induced reactions for 64Zn at low energies and their dependence on the chosen input parameters of the statistical model calculations. The new experimental data from the recent Atomki experiments allow for a χ2-based estimate of the uncertainties of calculated cross sections at very low energies. Method: Recently measured data for the (α ,γ ), (α ,n ), and (α ,p ) reactions on 64Zn are compared to calculations in the statistical model. A survey of the parameter space of the widely used computer code talys is given, and the properties of the obtained χ2 landscape are discussed. Results: The best fit to the experimental data at low energies shows χ2/F ≈7.7 per data point, which corresponds to an average deviation of about 30% between the best fit and the experimental data. Several combinations of the various ingredients of the statistical model are able to reach a reasonably small χ2/F , not exceeding the best-fit result by more than a factor of 2. Conclusions: The present experimental data for 64Zn in combination with the statistical model calculations allow us to constrain the astrophysical reaction rate within about a factor of 2. However, the significant excess of χ2/F of the best fit from unity demands further improvement of the statistical model calculations and, in particular, the α -nucleus potential.

  19. Transition from quasi-elastic to deep-inelastic reactions

    SciTech Connect

    Rehm, K.E.

    1986-01-01

    Heavy ion induced transfer reactions are usually considered to fall into two categories. Quasi-elastic processes, on one hand, are characterized by small energy transfers, with one-nucleon transfer reactions being a typical example. These processes are dominant for grazing collisions, and are generally described within simple one-step DWBA calculations. Deep inelastic reactions, on the other hand, occur for more central collisions where the interaction time is longer and subsequently more energy and particles can be exchanged. Quasi-elastic collisions dominate transfer reactions induced by light heavy ions (e.g., /sup 16/O) at energies not too high above the barrier, while deep inelastic collisions are observed mainly in reactions induced by heavier projectiles (Kr, Xe). In this contribution, we discuss the transition between these two processes for the system /sup 48/Ti + /sup 208/Pb. /sup 48/Ti is located between light (/sup 16/O) and heavy (Kr) projectiles and should be well suited for a study of the interrelation between quasi- and deep-inelastic reactions. The experiments were performed with a 300 MeV /sup 48/Ti beam obtained from the Argonne National Laboratory superconducting linac. The outgoing particles were momentum analyzed in a split pole magnetic spectrograph and detected in the focal plane by a position sensitive ionization chamber. The specific energy loss, the magnetic rigidity and the total energy of the outgoing particles were measured enabling mass and Z-identification. The energy resolution was about 3 MeV, determined by the thickness of the /sup 208/Pb target, and thus excluded study of transfer reactions to discrete final states. Angular distributions were measured in the range theta/sub lab/ = 20/sup 0/ to 80/sup 0/ in steps of 5/sup 0/. 8 refs.

  20. Simultaneous analysis of 17O/16O, 18O/16O and 2H/1H of gypsum hydration water by cavity ring‐down laser spectroscopy

    PubMed Central

    Mather, Ian; Rolfe, James; Evans, Nicholas P.; Herwartz, Daniel; Staubwasser, Michael; Hodell, David A.

    2015-01-01

    Rationale The recent development of cavity ring‐down laser spectroscopy (CRDS) instruments capable of measuring 17O‐excess in water has created new opportunities for studying the hydrologic cycle. Here we apply this new method to studying the triple oxygen (17O/16O, 18O/16O) and hydrogen (2H/1H) isotope ratios of gypsum hydration water (GHW), which can provide information about the conditions under which the mineral formed and subsequent post‐depositional interaction with other fluids. Methods We developed a semi‐automated procedure for extracting GHW by slowly heating the sample to 400°C in vacuo and cryogenically trapping the evolved water. The isotopic composition (δ17O, δ18O and δ2H values) of the GHW is subsequently measured by CRDS. The extraction apparatus allows the dehydration of five samples and one standard simultaneously, thereby increasing the long‐term precision and sample throughput compared with previous methods. The apparatus is also useful for distilling brines prior to isotopic analysis. A direct comparison is made between results of 17O‐excess in GHW obtained by CRDS and fluorination followed by isotope ratio mass spectrometry (IRMS) of O2. Results The long‐term analytical precision of our method of extraction and isotopic analysis of GHW by CRDS is ±0.07‰ for δ17O values, ±0.13‰ for δ18O values and ±0.49‰ for δ2H values (all ±1SD), and ±1.1‰ and ±8 per meg for the deuterium‐excess and 17O‐excess, respectively. Accurate measurement of the 17O‐excess values of GHW, of both synthetic and natural samples, requires the use of a micro‐combustion module (MCM). This accessory removes contaminants (VOCs, H2S, etc.) from the water vapour stream that interfere with the wavelengths used for spectroscopic measurement of water isotopologues. CRDS/MCM and IRMS methods yield similar isotopic results for the analysis of both synthetic and natural gypsum samples within analytical error of the two methods. Conclusions We

  1. Influence of exothermic chemical reactions on laser-induced shock waves.

    PubMed

    Gottfried, Jennifer L

    2014-10-21

    Differences in the excitation of non-energetic and energetic residues with a 900 mJ, 6 ns laser pulse (1064 nm) have been investigated. Emission from the laser-induced plasma of energetic materials (e.g. triaminotrinitrobenzene [TATB], cyclotrimethylene trinitramine [RDX], and hexanitrohexaazaisowurtzitane [CL-20]) is significantly reduced compared to non-energetic materials (e.g. sugar, melamine, and l-glutamine). Expansion of the resulting laser-induced shock wave into the air above the sample surface was imaged on a microsecond timescale with a high-speed camera recording multiple frames from each laser shot; the excitation of energetic materials produces larger heat-affected zones in the surrounding atmosphere (facilitating deflagration of particles ejected from the sample surface), results in the formation of additional shock fronts, and generates faster external shock front velocities (>750 m s(-1)) compared to non-energetic materials (550-600 m s(-1)). Non-explosive materials that undergo exothermic chemical reactions in air at high temperatures such as ammonium nitrate and magnesium sulfate produce shock velocities which exceed those of the inert materials but are less than those generated by the exothermic reactions of explosive materials (650-700 m s(-1)). The most powerful explosives produced the highest shock velocities. A comparison to several existing shock models demonstrated that no single model describes the shock propagation for both non-energetic and energetic materials. The influence of the exothermic chemical reactions initiated by the pulsed laser on the velocity of the laser-induced shock waves has thus been demonstrated for the first time.

  2. Some symmetry-induced isotope effects in the kinetics of recombination reactions.

    PubMed

    Pack, Russell T; Walker, Robert B

    2004-07-08

    Symmetry-induced isotope effects in recombination and collision-induced dissociation reactions are discussed. Progress on understanding the anomalous isotope effects in ozone is reviewed. Then, calculations are performed for the simpler reaction xNe+yNe+H<-->xNeyNe+H, where x and y label either identical or different isotopes. The atomic masses in the model are chosen so that symmetry is the only difference between the systems. Starting from a single potential energy surface, the properties of the bound, quasibound, and continuum states of the neon dimer are calculated. Then, the vibration rotation infinite order sudden approximation is used to calculate cross sections for all possible inelastic and dissociative processes. A rate constant matrix that exactly satisfies detailed balance is constructed. It allows recombination to occur both via direct three-body collisions and via tunneling into the quasibound states of the energy transfer mechanism. The eigenvalue rate coefficients are determined. Significant isotope effects are clearly found, and their behavior depends on the pressure, temperature, and mechanism of the reaction. Both spin statistics and symmetry breaking produce isotope effects. Under most conditions the breaking of symmetry enhances the rates, but a wide spectrum of effects is observed; they range from isotope effects with a normal mass dependence to huge, mass-independent isotope effects to cancellation and even to reversal of the isotope effects. This is the first calculation of symmetry-induced isotope effects in recombination rates from first principles. The relevance of the present effects to ozone recombination is discussed.

  3. Deformation-induced nanoscale mixing reactions in Cu/Ni and Ag/Pd multilayers

    SciTech Connect

    Wang, Z.; Perepezko, J. H.

    2013-11-04

    During the repeated cold rolling of Cu/Ni and Ag/Pd multilayers, a solid solution forms at the interfaces as nanoscale layer structure with a composition that replicates the overall multilayer composition. The interfacial mixing behavior was investigated by means of X-ray diffraction and scanning transmission electron microscopy. During deformation induced reaction, the intermixing behavior of the Cu/Ni and Ag/Pd multilayers is in contrast to thermally activated diffusion behavior. This distinct behavior can provide new kinetic pathways and offer opportunities for microstructure control that cannot be achieved by thermal processing.

  4. Noisy-flow-induced instability in a reaction-diffusion system

    NASA Astrophysics Data System (ADS)

    Paul, Shibashis; Ghosh, Shyamolina; Ray, Deb Shankar

    2016-12-01

    We consider a generic reaction-diffusion-advection system where the flow velocity of the advection term is subjected to dichotomous noise with zero mean and Ornstein-Zernike correlation. A general condition for noisy-flow-induced instability is derived in the flow velocity-correlation rate parameter plane. Full numerical simulations on Gierer-Meinhardt model with activator-inhibitor kinetics have been performed to show how noisy differential flow can lead to symmetry breaking of a homogeneous stable state in the presence of noise resulting in traveling waves.

  5. The design of dextran-based hypoxia-inducible hydrogels via in situ oxygen consuming reaction

    PubMed Central

    Park, Kyung Min; Blatchley, Michael R.; Gerecht, Sharon

    2014-01-01

    Hypoxia plays a critical role in development and the wound healing process, as well as a number of pathological conditions. Here, we report dextran–based hypoxia–inducible (Dex–HI) hydrogels formed with in situ oxygen consumption via laccase–medicated reaction. Oxygen levels and gradients were accurately predicted by mathematical simulation. We demonstrate that Dex–HI hydrogels provide prolonged hypoxic conditions up to 12 h. The Dex–HI hydrogel offers an innovative approach to delineate not only the mechanism by which hypoxia regulates cellular responses, but may facilitate the discovery of new pathways involved in the generation of hypoxic and oxygen gradient environments. PMID:25303104

  6. Catalysis of Dialanine Formation by Glycine in the Salt-Induced Peptide Formation Reaction.

    NASA Astrophysics Data System (ADS)

    Suwannachot, Yuttana; Rode, Bernd M.

    1998-02-01

    Mutual catalysis of amino acids in the salt-induced peptide formation (SIPF) reaction is demonstrated for the case of glycine/alanine. The presence of glycine enhances dialanine formation by a factor up to 50 and enables dialanine formation at much lower alanine concentrations. The actual amounts of glycine play an important role for this catalytic effect, the optimal glycine concentration is 1/8 of the alanine concentration. The mechanism appears to be based on the formation of the intermediate Gly-Ala-Ala tripeptide, connected to one coordination site of copper(II) ion, and subsequent hydrolysis to dialanine and glycine.

  7. Theory of photon and electron induced reactions. Progress report, July 1, 1991--June 30, 1992

    SciTech Connect

    Onley, D.S.; Wright, L.E.

    1992-01-01

    During the first year and half of the current grant from the Department of Energy we have made considerable progress on the following aspects of the general investigation of electron and photon induced reactions: (1) photo- and electro-production of mesons; (2) Coulomb distortion effects on (e,e{prime}{gamma}) and (e,e{prime}) and (e,e{prime}p) in the quasi-elastic region, (3) studies involving the relativistic shell model, and (4) quark models. We will report on each of these developments in this paper.

  8. 12C(16O,γ)28Si radiative capture: Structural and statistical aspects of the γ decay

    NASA Astrophysics Data System (ADS)

    Lebhertz, D.; Courtin, S.; Haas, F.; Jenkins, D. G.; Simenel, C.; Salsac, M.-D.; Hutcheon, D. A.; Beck, C.; Cseh, J.; Darai, J.; Davis, C.; Glover, R. G.; Goasduff, A.; Kent, P. E.; Levai, G.; Marley, P. L.; Michalon, A.; Pearson, J. E.; Rousseau, M.; Rowley, N.; Ruiz, C.

    2012-03-01

    The heavy-ion radiative capture reaction 12C(16O,γ)28Si has been studied at three energies Ec.m.=8.5, 8.8, and 9 MeV which are close to the Coulomb barrier. The weak radiative capture process has been identified by measuring the 28Si recoils in the highly selective 0∘ spectrometer DRAGON at TRIUMF (Vancouver). The coincident γ rays have been recorded in the associated BGO array. This has allowed a complete measurement of the γ spectrum and the relative strength of all decay pathways. An important part of the decay through quasibound states close to the particle threshold and the feeding of bound states with particular deformation have been identified for the first time. Comparisons with Monte Carlo simulations allowed the extraction of the full experimental radiative capture cross section. Our results suggest an important contribution of spins Jπ=5- and 6+ in the entrance channel. The surprisingly large cross sections from 12 μb at Ec.m.=8.5 MeV to 25 μb at Ec.m.=9.0 MeV for the heavy-ion radiative capture process are discussed in terms of the interplay between statistical and structural aspects of the process.

  9. Quantitative Proteomic Approach for MicroRNA Target Prediction Based on 18O/16O Labeling

    PubMed Central

    Ma, Xuepo; Zhu, Ying; Huang, Yufei; Tegeler, Tony; Gao, Shou-Jiang; Zhang, Jianqiu

    2015-01-01

    MOTIVATION Among many large-scale proteomic quantification methods, 18O/16O labeling requires neither specific amino acid in peptides nor label incorporation through several cell cycles, as in metabolic labeling; it does not cause significant elution time shifts between heavy- and light-labeled peptides, and its dynamic range of quantification is larger than that of tandem mass spectrometry-based quantification methods. These properties offer 18O/16O labeling the maximum flexibility in application. However, 18O/16O labeling introduces large quantification variations due to varying labeling efficiency. There lacks a processing pipeline that warrants the reliable identification of differentially expressed proteins (DEPs). This motivates us to develop a quantitative proteomic approach based on 18O/16O labeling and apply it on Kaposi sarcoma-associated herpesvirus (KSHV) microRNA (miR) target prediction. KSHV is a human pathogenic γ-herpesvirus strongly associated with the development of B-cell proliferative disorders, including primary effusion lymphoma. Recent studies suggest that miRs have evolved a highly complex network of interactions with the cellular and viral transcriptomes, and relatively few KSHV miR targets have been characterized at the functional level. While the new miR target prediction method, photoactivatable ribonucleoside-enhanced cross-linking and immunoprecipitation (PAR-CLIP), allows the identification of thousands of miR targets, the link between miRs and their targets still cannot be determined. We propose to apply the developed proteomic approach to establish such links. METHOD We integrate several 18O/16O data processing algorithms that we published recently and identify the messenger RNAs of downregulated proteins as potential targets in KSHV miR-transfected human embryonic kidney 293T cells. Various statistical tests are employed for picking DEPs, and we select the best test by examining the enrichment of PAR-CLIP-reported targets with

  10. EPR study of shock and thermally induced reaction in solid copper tetramine nitrate

    NASA Astrophysics Data System (ADS)

    Owens, F. J.

    1982-12-01

    Electron paramagnetic resonance studies of copper tetramine nitrate, subjected to explosive shock loading and analyzed after recovery, indicate that the Cu(NH3)2+4 complex is completely converted to Cu(NH3)2+2. The same reaction could also be induced by isothermal heating of the material for 1 h at +160 °C. The intrinsic linewidth of the Cu(NH3)2+2 complex in the shocked material was larger by a factor of 3 compared to the linewidth of the spectrum produced by isothermal decomposition. The perpendicular g shift was also slightly different. These differences are attributed to shock-induced defects in the material. When a foil flyer plate electric gun is used to shock CTN, the conversion to Cu(NH3)2+2 was not observed, but evidence of a new spectrum was obtained.

  11. Measurement of the Induced Proton Polarization Pn in the 12C(e, e', p) reaction

    SciTech Connect

    Woo, R J; Barkhuff, David; Bertozzi, William; Chen, Jian-ping; Dale, Dan; Dodson, G; Dow, K A; Epstein, Marty; Farkhondeh, Manouchehr; Finn, Mike; Gilad, Shalev; Jones, Mark K; Joo, Kyungseon; Kelly, James; Kowalski, Stanley; Lourie, Bob; Madey, Richard; Margaziotis, Dimitri; Markowitz, Pete; McIntyre, Justin; Mertz, Christoph; Milbrath, Brian; Mitchell, Joseph; Perdrisat, Charles F; Punjabi, Vina; Rutt, Paul; Sarty, Adam; Tieger, D; Tschalaer, C; Turchinetz, William; Ulmer, Paul E; Van Verst, S P; Vellidis, C; Warren, Glen; Weinstein, Lawrence

    1998-01-19

    The first measurements of the induced proton polarization Pn for the 12C(e,e',p) reaction are reported. The experiment was performed at quasifree kinematics for energy and momentum transfer (w,q) = (294 MeV, 765 MeV/c) and sampled a missing momentum range of 0-250 MeV/c. The induced polarization arises from final-state interactions and for these kinematics is dominated by the real part of the spin-orbit optical potential. The distorted-wave impulse approximation provides good agreement with data for the 1 p3/2 shell. The data for the continuum suggest that both the 1s1/2 shell and underlying l > 1 configurations contribute.

  12. Study of the 17O(n,α)14C reaction: Extension of the Trojan Horse Method to neutron induced reactions

    NASA Astrophysics Data System (ADS)

    Guardo, G. L.; Lamia, L.; Spitaleri, C.; Gulino, M.; Tang, X. D.; Bucher, B.; Burjan, V.; Cherubini, S.; Couder, M.; Davies, P.; deBoer*, R.; Fang, X.; Goldberg, V. Z.; Hons, Z.; Kroha, V.; Lamm, L.; La Cognata, M.; Li, C.; Ma, C.; Mrazek, J.; Mukhamedzhanov, A. M.; Notani, M.; OBrien, S.; Pizzone, R. G.; Rapisarda, G. G.; Roberson, D.; Sergi, M. L.; Tan, W.; Thompson, I. J.; Wiescher, M.

    2014-05-01

    The experimental study of the 17O(n,α)14C reaction has been performed in the energy range 0-350 keV. This reaction could play an important role in explaining heavy elements (s-process) nucleosynthesis in various astrophysical scenario. To overcome the practical problems arising from the neutrons production, a new application of the Trojan Horse Method has been recently suggested. In more details, the 17O(n,α)14C reaction has been studied using the quasi-free 2H(17O,α14C)1H reaction, induced at an energy of 43.5 MeV. The measurement allows one to investigate the ℓ=3, 75 keV resonance (E*=8.125 MeV, Jπ=5-), absent in the available direct measurements because of centrifugal suppression effects.

  13. Morphine-induced Straub tail reaction in mice treated with serotonergic compounds.

    PubMed

    Belozertseva, Irina V; Dravolina, Olga A; Tur, Margarita A; Semina, Marina G; Zvartau, Edwin E; Bespalov, Anton Yu

    2016-11-15

    Constitutively active 5-HT2 receptors have been suggested to contribute to motoneuronal excitability, muscle spasms and spasticity. Accordingly, 5-HT2C receptor inverse agonists have been demonstrated in pilot experiments to reduce spasticity in animal model of spasticity and patients with spinal cord injuries. Thus, 5-HT2C receptor inverse agonists may represent a novel class of anti-spasticity agents justifying a search for compounds with robust 5-HT2C receptor inverse agonist activity either among the existing medications or via a dedicated drug discovery program. Morphine-induced Straub tail response in mice is regarded as a model of transient spasticity that may be suitable for supporting such drug discovery efforts. Subcutaneous injection of morphine (10-60mg/kg) induced a dose-dependent Straub tail reaction in male Swiss mice with maximum response obtained 15-30min after the morphine administration. When given prior to morphine, 5-HT2B/2C receptor inverse agonists cyproheptadine (1-10mg/kg, i.p.) and SB206553 (0.3-3mg/kg, i.p.) diminished Straub tail reaction dose-dependently without affecting spontaneous locomotor activity. In contrast, 5-HT2B/2C receptor antagonist methysergide (1-5.6mg/kg, i.p.) and 5-HT2C receptor antagonist SB242084 (1-5.6mg/kg, i.p.) as well as 5-HT2A receptor inverse agonist pimavanserin (1-10mg/kg, i.p.) had no appreciable effects on Straub tail response. Taken together, the findings indicate that constitutive activity of 5-HT2B/2C receptor may be involved in the mechanisms of morphine-induced spasticity. Thus, morphine-induced Straub tail response may be evaluated further as a candidate higher throughput test to identify 5-HT2C receptor inverse agonists with anti-spasticity effects in vivo.

  14. Covariance of Neutron Cross Sections for {sup 16}O through R-matrix Analysis

    SciTech Connect

    Kunieda, S.; Kawano, T.; Paris, M.; Hale, G.M.; Shibata, K.; Fukahori, T.

    2015-01-15

    Through the R-matrix analysis, neutron cross sections as well as the covariance are estimated for {sup 16}O in the resolved resonance range. Although we consider the current results are still preliminary, we present the summary of the cross section analysis and the results of data uncertainty/covariance, including those for the differential cross sections. It is found that the values obtained highlight consequences of nature in the theory as well as knowledge from measurements, which gives a realistic quantification of evaluated nuclear data covariances.

  15. Possible mechanisms of fragmentation of {sup 16}O nuclei with a momentum of 4.5 GeV/c per nucleon in track emulsions

    SciTech Connect

    Kotikov, E. A.

    2013-06-15

    The angular distributions of doubly charged fragments of {sup 16}O nuclei having a momentum of 4.5 GeV/c per nucleon and interacting with track-emulsion nuclei were studied. The experimental angular distributions of doubly charged fragments of a {sup 16}O nucleus are not described by the statistical model of the fragmentation of nuclei. The possible channels of fragmentation of {sup 16}O nuclei may include {sup 16}O {yields} 2{sup 8}Be {yields} 4{alpha}, {sup 16}O {yields} {sup 8}Be +{sup 8} Be* {yields} 4{alpha}, {sup 16}O {yields} 2{sup 8}Be* {yields} 4{alpha}, {sup 16}O {yields} {alpha}+{sup 12}C, {sup 16}O {yields} {alpha} +{sup 12}C* {yields} {alpha} + 3{alpha}, {sup 16}O {yields} {alpha} +{sup 12}C* {yields} {alpha} + p{alpha}{sup 7}Li, {sup 16}O {yields} {alpha} +{sup 12}C* {yields} {alpha} + 2{sup 6}Li, {sup 16}O {yields} {alpha} +{sup 12}C* {yields} {alpha} + pt2{alpha}, {sup 16}O {yields} Li + B, and {sup 16}O {yields} Li* + B*.

  16. Local inflammatory reaction induced by Scolopendra viridicornis centipede venom in mice.

    PubMed

    Kimura, Louise Faggionato; Prezotto-Neto, José Pedro; Távora, Bianca de Carvalho Lins Fernandes; Antoniazzi, Marta Maria; Knysak, Irene; Gióia Guizze, Samuel Paulo; Santoro, Marcelo Larami; Barbaro, Katia Cristina

    2013-12-15

    Centipede envenomation is generally mild, and human victims usually manifest burning pain, erythema and edema. Despite the abundance and ubiquity of these animals, centipede venom has been poorly characterized in literature. For this reason, the aim of this work was to investigate local inflammatory features induced by Scolopendra viridicornis centipede envenomation in mice, evaluating edema formation, leukocyte infiltration, production of inflammatory mediators, and also performing histological analysis. The highest edematogenic activity induced by the venom, determined by plethysmometry, was noticed 0.5 h after injection in mice footpad. At 24 h, edema was still detected in animals that received 15 and 60 μg of venom, and at 48 h, only in animals injected with 60 μg of venom. In relation to leukocyte count, S. viridicornis venom induced cell recruitment, mainly neutrophils and monocytes/macrophages, in all doses and time periods analyzed in comparison with PBS-injected mice. An increase in lymphocytes was detected especially between 1 and 24 h at 60 μg dose. Besides, eosinophil recruitment was observed mainly for 15 and 60 μg doses in early time periods. Edema formation and cell recruitment were also confirmed by histological analysis. Moreover, S. viridicornis venom stimulated the release of IL-6, MCP-1, KC, and IL-1β. Conversely, S. viridicornis venom did not induce the release of detectable levels of TNF-α. We demonstrated that the edematogenic activity induced by S. viridicornis venom was of rapid onset, and the venom stimulated secretion of pro-inflammatory mediators which contribute to the inflammatory reaction induced by S. viridicornis venom in an experimental model.

  17. Fast and efficient synthesis of microporous polymer nanomembranes via light-induced click reaction

    PubMed Central

    An, Qi; Hassan, Youssef; Yan, Xiaotong; Krolla-Sidenstein, Peter; Mohammed, Tawheed; Lang, Mathias; Bräse, Stefan

    2017-01-01

    Conjugated microporous polymers (CMPs) are materials of low density and high intrinsic porosity. This is due to the use of rigid building blocks consisting only of lightweight elements. These materials are usually stable up to temperatures of 400 °C and are chemically inert, since the networks are highly crosslinked via strong covalent bonds, making them ideal candidates for demanding applications in hostile environments. However, the high stability and chemical inertness pose problems in the processing of the CMP materials and their integration in functional devices. Especially the application of these materials for membrane separation has been limited due to their insoluble nature when synthesized as bulk material. To make full use of the beneficial properties of CMPs for membrane applications, their synthesis and functionalization on surfaces become increasingly important. In this respect, we recently introduced the solid liquid interfacial layer-by-layer (LbL) synthesis of CMP-nanomembranes via Cu catalyzed azide–alkyne cycloaddition (CuAAC). However, this process featured very long reaction times and limited scalability. Herein we present the synthesis of surface grown CMP thin films and nanomembranes via light induced thiol–yne click reaction. Using this reaction, we could greatly enhance the CMP nanomembrane synthesis and further broaden the variability of the LbL approach.

  18. Parameterization of fusion barriers for light-projectiles-induced reactions using the proximity approach

    NASA Astrophysics Data System (ADS)

    Gharaei, R.; Sheibani, J.

    2016-05-01

    In this article we propose a pocket formula for fusion barriers calculated by three versions of the proximity formalism, namely AW 95, Bass 80 and Prox. 2010 potentials, for fusion reactions involving the collisions of the proton and helium projectiles with different targets in mass ranges 51≤ AT ≤ 130 and 40≤ AT ≤ 233 , respectively. For the first type of the colliding systems, it is shown that the proposed pocket formulas are able to predict the actual values of RB and VB within accuracies of ±0.4% and ±0.45% , respectively. Moreover, for the second type of the selected reactions, these accuracies are obtained ±0.24% and ±0.36% , respectively. In this study, the ability of the present pocket formulas is also demonstrated to predict the exact values of the fusion cross sections for our selected mass ranges. A comparison with the results of the previous pocket formulas reveals that our parameterized forms are more successful to reproduce the empirical data of the barrier height and position in the proton- and helium-induced reactions.

  19. Bayesian Evaluation Including Covariance Matrices of Neutron-induced Reaction Cross Sections of {sup 181}Ta

    SciTech Connect

    Leeb, H. Schnabel, G.; Srdinko, Th.; Wildpaner, V.

    2015-01-15

    A new evaluation of neutron-induced reactions on {sup 181}Ta using a consistent procedure based on Bayesian statistics is presented. Starting point of the evaluation is the description of nuclear reactions via nuclear models implemented in TALYS 1.4. A retrieval of experimental data was performed and covariance matrices of the experiments were generated from an extensive study of the corresponding literature. All reaction channels required for a transport file up to 200 MeV have been considered and the covariance matrices of cross section uncertainties for the most important channels are determined. The evaluation has been performed in one step including all available experimental data. A comparison of the evaluated cross sections and spectra with experimental data and available evaluations is performed. In general the evaluated cross section reflect our best knowledge and give a fair description of the observables. However, there are few deviations from expectation which clearly indicate the impact of the prior and the need to account for model defects. Using the results of the evaluation a complete ENDF-file similarly to those of the TENDL library is generated.

  20. Liquid-phase reactions induced by atmospheric pressure glow discharge with liquid electrode

    NASA Astrophysics Data System (ADS)

    Tochikubo, Fumiyoshi; Shirai, Naoki; Uchida, Satoshi

    2014-12-01

    We experimentally investigated some of the initial reactions in a liquid induced by electron or positive-ion irradiation from an atmospheric-pressure dc glow discharge in contact with the liquid. We used an H-shaped glass reactor to observe the effects of electron irradiation and positive-ion irradiation on the liquid-phase reaction separately and simultaneously. Aqueous solutions of NaCl, AgNO3, HAuCl4, and FeCl2 are used as the electrolyte. Solutions of AgNO3 and HAuCl4 are used for the generation of Ag and Au nanoparticles, respectively. Solution of FeCl2 is used for the generation of ferromagnetic particles. Experimental results showed that electron irradiation of the liquid surface generates OH- in water and that positive-ion irradiation of the liquid surface generates H+ in water even without the dissolution of gas-phase nitrogen oxide. A possible reaction process is qualitatively discussed. We also showed that the control of reductive and oxidative environment in the liquid is possible not only by the gas composition for the plasma generation but also by the liquid composition.

  1. Autonomous Oscillation of Polymer Chains Induced by the Belousov–Zhabotinsky Reaction

    PubMed Central

    Hara, Yusuke; Takenaka, Yoshiko

    2014-01-01

    We investigated the self-oscillating behaviors of two types of polymer chains induced by the Belousov–Zhabotinsky (BZ) reaction. One consisted of N-isopropylacrylamide (NIPAAm) and the Ru catalyst of the BZ reaction, and the other consisted of NIPAAm, the Ru catalyst, and acrylamide-2-methylpropanesulfonic acid (AMPS) with a negatively charged domain as a solubility control site. A comparison of the two types of self-oscillation systems showed that the anionic AMPS portion of the polymer chain significantly affected the self-oscillating behavior under strongly acidic condition. The periods of self-oscillation for the two types of self-oscillating polymer chains were investigated by changing the initial concentrations of the three BZ substrates and the temperature. As a result, it was demonstrated that the period of self-oscillation could be controlled by the concentration of the BZ substrates and the temperature. Furthermore, the activation energies of the two types of the self-oscillating polymer chains gave similar values as normal BZ reactions, i.e., not including the self-oscillating polymer system with a Ru moiety. In addition, it was clarified the activation energy was hardly affected by the initial concentration of the three BZ substrates. PMID:24434841

  2. Rapamycin protects neurons from brain contusion-induced inflammatory reaction via modulation of microglial activation

    PubMed Central

    SONG, QI; XIE, DUJIANG; PAN, SHIYONG; XU, WEIJUN

    2015-01-01

    The inflammatory reaction is important in secondary injury following traumatic brain injury (TBI). Rapamycin has been demonstrated as a neuroprotective agent in a mouse model of TBI, however, there is a lack of data regarding the effects of rapamycin on the inflammatory reaction following TBI. Therefore, the present study was designed to assess the effects of treatment with rapamycin on inflammatory reactions and examine the possible involvement of microglial activation following TBI. Male imprinting control region mice were randomly divided into four groups: Sham group (n=23), TBI group (n=23), TBI + dimethyl sulfoxide (DMSO) group (n=31) and TBI + rapamycin group (n=31). Rapamycin was dissolved in DMSO (50 mg/ml) and injected 30 min after TBI (2 mg/Kg; intraperitoneally). A weight-drop model of TBI was induced, and the brain tissues were harvested 24 h after TBI. The findings indicated that the administration of rapamycin following TBI was associated with decreased levels of activated microglia and neuron degeneration at the peri-injury site, reduced levels of proinflammatory cytokines and increased neurobehavioral function, possibly mediated by inactivation of the mammalian target of rapamycin pathway. The results of the present study offer novel insight into the mechanisms responsible for the anti-neuroinflammatory effects of rapamycin, possibly involving the modulation of microglial activation. PMID:26458361

  3. Active Target-Time Projection Chambers for Reactions Induced by Rare Isotope Beams: Physics and Technology

    NASA Astrophysics Data System (ADS)

    Mittig, Wolfgang

    2013-04-01

    Weakly bound nuclear systems can be considered to represent a good testing-ground of our understanding of non-perturbative quantum systems. Great progress in experimental sensitivity has been attained by increase in rare isotope beam intensities and by the development of new high efficiency detectors. It is now possible to study reactions leading to bound and unbound states in systems with very unbalanced neutron to proton ratios. Application of Active Target-Time Projection Chambers to this domain of physics will be illustrated by experiments performed with existing detectors. The NSCL is developing an Active Target-Time Projection Chamber (AT-TPC) to be used to study reactions induced by rare isotope beams at the National Superconducting Cyclotron Facility (NSCL) and at the future Facility for Rare Isotope Beams (FRIB). The AT-TPC counter gas acts as both a target and detector, allowing investigations of fusion, isobaric analog states, cluster structure of light nuclei and transfer reactions to be conducted without significant loss in resolution due to the thickness of the target. The high efficiency and low threshold of the AT-TPC will allow investigations of fission barriers and giant resonances with fast fragmentation rare isotope beams. This detector type needs typically a large number of electronic channels (order of magnitude 10,000) and a high speed DAQ. A reduced size prototype detector with prototype electronics has been realized and used in several experiments. A short description of other detectors of this type under development will be given.

  4. Photo-induced reactions in the ion-molecule complex Mg+-OCNC2H5

    NASA Astrophysics Data System (ADS)

    Sun, Ju-Long; Liu, Haichuan; Han, Ke-Li; Yang, Shihe

    2003-06-01

    Ion-molecule complexes of magnesium cation with ethyl isocyanate were produced in a laser-ablation supersonic expansion nozzle source. Photo-induced reactions in the 1:1 complexes have been studied in the spectral range of 230-410 nm. Photodissociation mass spectrometry revealed the persistent product Mg+ from nonreactive quenching throughout the entire wavelength range. As for the reactive channels, the photoproducts, Mg+OCN and C2H5+, were produced only in the blue absorption band of the complex with low yields. The action spectrum of Mg+(OCNC2H5) consists of two pronounced peaks on the red and blue sides of the Mg+ 32P←32S atomic transition. The ground state geometry of Mg+-OCNC2H5 was fully optimized at B3LYP/6-31+G** level by using GAUSSIAN 98 package. The calculated absorption spectrum of the complex using the optimized structure of its ground state agrees well with the observed action spectrum. Photofragment branching fractions of the products are almost independent of the photolysis photon energy for the 3Px,y,z excitations. The very low branching ratio of reactive products to nonreactive fragment suggests that evaporation is the main relaxation pathway in the photo-induced reactions of Mg+(OCNC2H5).

  5. H2 16O line list for the study of atmospheres of Venus and Mars

    NASA Astrophysics Data System (ADS)

    Lavrentieva, N. N.; Voronin, B. A.; Fedorova, A. A.

    2015-01-01

    IR spectroscopy is an important method of remote measurement of H2 16O content in planetary atmospheres with initial spectroscopic information from the HITRAN, GEISA, etc., databases adapted for studies in the Earth's atmosphere. Unlike the Earth, the atmospheres of Mars and Venus mainly consist of carbon dioxide with a CO2 content of about 95%. In this paper, the line list of H2 16O is obtained on the basis of the BT2 line list (R.J. Barber, J. Tennyson, G.J. Harris, et al., Mon. Not. R. Astron. Soc. 368, 1087 (2006)). The BT2 line list containing information on the centers, intensities, and quantum identification of lines is supplemented with the line contour parameters: the self-broadening and carbon dioxide broadening coefficients and the temperature dependence coefficient at 296 K in the range of 0.001-30000 cm-1. Transitions with intensity values 10-30, 10-32, and 10-35 cm/molecule, the total number of which is 323310, 753529, and 2011072, respectively, were chosen from the BT2 line list.

  6. Very low-energy nucleon-16O coupled-channel scattering: Results with a phenomenological vibrational model

    NASA Astrophysics Data System (ADS)

    Svenne, J. P.; Canton, L.; Amos, K.; Fraser, P. R.; Karataglidis, S.; Pisent, G.; van der Knijff, D.

    2017-03-01

    We employ a collective vibration coupled-channel model to describe the nucleon-16O cluster systems, obtaining low-excitation spectra for 17O and 17F. Bound and resonance states of the compound systems have been deduced, showing good agreement with experimental spectra. Low-energy scattering cross sections of neutrons and protons from 16O also have been calculated and the results compare well with available experimental data.

  7. Use of microgravity sensors for quantification of space shuttle orbiter vernier reaction control system induced environments

    NASA Technical Reports Server (NTRS)

    Friend, Robert B.

    1998-01-01

    In the modeling of spacecraft dynamics it is important to accurately characterize the environment in which the vehicle operates, including the environments induced by the vehicle itself. On the Space Shuttle these induced environmental factors include reaction control system plume. Knowledge of these environments is necessary for performance of control systems and loads analyses, estimation of disturbances due to thruster firings, and accurate state vector propagation. During the STS-71 mission, while the Orbiter was performing attitude control for the mated Orbiter/Mir stack, it was noted that the autopilot was limit cycling at a rate higher than expected from pre-flight simulations. Investigations during the mission resulted in the conjecture that an unmodelled plume impingement force was acting upon the orbiter elevons. The in-flight investigations were not successful in determining the actual magnitude of the impingement, resulting in several sequential post-flight investigations. Efforts performed to better quantify the vernier reaction control system induced plume impingement environment of the Space Shuttle orbiter are described in this paper, and background detailing circumstances which required the more detailed knowledge of the RCS self impingement forces, as well as a description of the resulting investigations and their results is presented. The investigations described in this paper applied microgravity acceleration data from two shuttle borne microgravity experiments, SAMS and OARE, to the solution of this particular problem. This solution, now used by shuttle analysts and mission planners, results in more accurate propellant consumption and attitude limit cycle estimates in preflight analyses, which are critical for pending International Space Station missions.

  8. Low energy electron induced fragmentation and reactions of DNA and its molecular components

    NASA Astrophysics Data System (ADS)

    Bass, Andrew

    2005-05-01

    Much research has been stimulated by the recognition that ionizing radiation can, in condensed matter, generate large numbers of secondary electrons with energies less than 20 eV [1] and by the experimental demonstration that such electrons may induce both single and double strand breaks in plasmid DNA [2]. Identifying the underlying mechanisms involves several research methodologies, from further experiments with DNA to studies of the electron interaction with the component `sub-units' of DNA in both the gas and condensed phases [3]. In particular, understanding electron-induced strand break damage, the type of damage most difficult for organisms to repair, necessitates study of the sub-units of DNA back-bone, and here Tetrahyrofuran (THF) and its derivatives, provide a useful model for the furyl ring at the centre of the deoxyribose sugar. In this contribution, we review with particular reference to DNA and related molecules, the use of electron spectroscopy and mass spectrometry to study electron-induced fragmentation and reactions in thin molecular solids. We describe a newly completed instrument that combines laser post-ionization with a time-of-flight mass analyzer for highly sensitive ion and neutral detection. Use of the instrument is illustrated with results for THF and derivatives. Anion desorption measurements reveal the role of transient negative ions (TNI) and Dissociative Electron Attachment in significant molecular fragmentation and permit effective cross sections for this electron-induced damage to be obtained. The neutral yield functions also illustrate the importance of TNI, mirroring features seen in recently measured cross sections for electron induced aldehyde production in THF [4]. 1. J. A. Laverne and S. M. Pimblott, Radiat. Res. 141, 208 (1995) 2. B. Boudaiffa, et al, Science 287, 1658 (2000) 3. L. Sanche. Physica Scripta. 68, C108, (2003) 4. S.-P. Breton, et al.,J. Chem. Phys. 121, 11240 (2004)

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

    SciTech Connect

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

    2012-07-01

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

  10. A full dimensional time-dependent wave packet study for the H4 four-center, collision induced dissociation, and single exchange reactions: reaction probabilities for J=0.

    PubMed

    Lu, Yunpeng; Lee, Soo-Y; Zhang, Dong H

    2006-01-07

    A time-dependent initial state selected wave packet method has been developed to study the H2(v(1)=10-11,j1=0)+H2'(v2=0,j2=0)-->HH'+HH' four-center (4C) reaction, and two other competing reactions: the H2+H2'-->H+H+H2' collision induced dissociation (CID) and the H2+H2'-->H+HH'+H' single exchange (SE) reaction, in full six dimensions. Initial state-specific total reaction probabilities for these three competing reactions are presented for total angular momentum J=0 and the effects of reagent vibration on reactions are examined. It is found that (a) the CID process is the dominant process over the whole energy range considered in this study, but the 4C and SE processes also have non-negligible probabilities; (b) the SE process has a lower threshold energy than the 4C process, but the SE probability increases slower than the 4C probability as collision energy increases; (c) the vibrational excitation of H2(v1) is much more efficient than translational motion for promoting these processes, in particular to the CID process.

  11. HLA class I markers in Japanese patients with carbamazepine-induced cutaneous adverse reactions.

    PubMed

    Ikeda, Hiroko; Takahashi, Yukitoshi; Yamazaki, Etsuko; Fujiwara, Tateki; Kaniwa, Nahoko; Saito, Yoshiro; Aihara, Michiko; Kashiwagi, Mariko; Muramatsu, Masaaki

    2010-02-01

    Carbamazepine (CBZ) is frequently used for treating epilepsy, but this drug causes cutaneous adverse drug reactions (cADRs) that may range from mild to severe. It is reported recently that the human leukocyte antigen HLA-B*1502 is associated with Stevens-Johnson syndrome (SJS) induced by CBZ in Han Chinese. We examined HLA class I in 15 Japanese patients who fulfilled the diagnostic criteria for CBZ-induced cADRs (mild in 10 and severe = SJS in 5). HLA-B*1518, HLA-B*5901 and HLA-C*0704 alleles showed higher relative risks (above 10.0) for severe cADRs. The haplotype (HLA-A*2402-B*5901-C*0102) had high relative risk (16.09) for severe cADRs. In patients with severe cADRs, frequencies of HLA-A*1101, HLA-A*3303, HLA-B*1501, HLA-B*4403, HLA-B*5101, HLA-B*5201, HLA-C*0702, and HLA-C*1202 alleles are relatively lower than in the Japanese population. These data may suggest that HLA-B*5901 is one of the candidate markers for CBZ-induced SJS in Japanese.

  12. Chemical reaction networks as a model to describe UVC- and radiolytically-induced reactions of simple compounds.

    PubMed

    Dondi, Daniele; Merli, Daniele; Albini, Angelo; Zeffiro, Alberto; Serpone, Nick

    2012-05-01

    When a chemical system is submitted to high energy sources (UV, ionizing radiation, plasma sparks, etc.), as is expected to be the case of prebiotic chemistry studies, a plethora of reactive intermediates could form. If oxygen is present in excess, carbon dioxide and water are the major products. More interesting is the case of reducing conditions where synthetic pathways are also possible. This article examines the theoretical modeling of such systems with random-generated chemical networks. Four types of random-generated chemical networks were considered that originated from a combination of two connection topologies (viz., Poisson and scale-free) with reversible and irreversible chemical reactions. The results were analyzed taking into account the number of the most abundant products required for reaching 50% of the total number of moles of compounds at equilibrium, as this may be related to an actual problem of complex mixture analysis. The model accounts for multi-component reaction systems with no a priori knowledge of reacting species and the intermediates involved if system components are sufficiently interconnected. The approach taken is relevant to an earlier study on reactions that may have occurred in prebiotic systems where only a few compounds were detected. A validation of the model was attained on the basis of results of UVC and radiolytic reactions of prebiotic mixtures of low molecular weight compounds likely present on the primeval Earth.

  13. Synthesis, crystal and electronic structures, and magnetic properties of LiLn9Mo16O35 (Ln = La, Ce, Pr, and Nd) compounds containing the original cluster Mo16O36.

    PubMed

    Gougeon, Patrick; Gall, Philippe; Cuny, Jérôme; Gautier, Régis; Le Pollès, Laurent; Delevoye, Laurent; Trébosc, Julien

    2011-12-02

    The new compounds LiLn(9)Mo(16)O(35) (Ln=La, Ce, Pr, and Nd) were synthesized from stoichiometric mixtures of Li(2)MoO(4), Ln(2)O(3), Pr(6)O(11) or CeO(2), MoO(3), and Mo heated at 1600 °C for 48 h in a molybdenum crucible sealed under a low argon pressure. The crystal structure, determined from a single crystal of the Nd member, showed that the main building block is the Mo(16)O(36) unit, the Mo(16) core of which is totally new and results from the fusion of two bioctahedral Mo(10) clusters. It can also be viewed as a fragment of an infinite twin chain of edge-sharing Mo(6) octahedra. The Mo(16)O(36) cluster units share some oxygen atoms to form infinite chains running parallel to the b axis, which are separated by the rare-earth and lithium cations. (7)Li-NMR experiments, carried out at high field on the nonmagnetic LiLa(9)Mo(16)O(35), provided insights into the local environment of the lithium ions. Magnetic susceptibility measurements confirmed the trivalent oxidation state of the magnetic rare-earth cations and indicated the absence of localized moments on the Mo(16) clusters. The electronic structure of the LiLn(9)Mo(16)O(35) compounds was analyzed using molecular and periodic quantum calculations. The study of the molecular orbital diagrams of isolated Mo(16)O(36) models allowed the understanding of this unique metallic architecture. Periodic density functional theory calculations demonstrated that few interactions occur between the Mo(16) clusters, and predicted semiconducting properties for LiLn(9)Mo(16)O(35) as a band gap of 0.57 eV was computed for the lanthanum phase.

  14. Production of heavy actinides from interactions of /sup 16/O, /sup 18/O, /sup 20/Ne, and /sup 22/Ne with /sup 248/Cm

    SciTech Connect

    Lee, D.; von Gunten, H.; Jacak, B.; Nurmia, M.; Liu, Y.; Luo, C.; Seaborg, G.T.; Hoffman, D.C.

    1982-01-01

    We have measured cross sections for the production of isotopes of Bk through No in bombardments of /sup 248/Cm with /sup 16/O, /sup 18/O, /sup 20/Ne, and /sup 22/Ne ions at energies near the Coulomb barrier. In general, the peak of the mass-yield curve for each element is about two mass units larger for /sup 18/O and /sup 22/Ne than for /sup 16/O and /sup 20/Ne, reflecting the neutron excess of the projectiles. The production cross sections and maxima of the actinide isotopic distributions are at least as favorable for production of neutron-rich actinides as those measured for irradiation of /sup 238/U and /sup 248/Cm with very heavy ions. The observation of so many neutron-rich products between the masses of the target and compound nucleus suggests a direct transfer reaction in which the product nuclide is formed with relatively low excitation which minimizes depletion from prompt fission.

  15. Hydrochemistry and 18O/16O and 2H/1H Ratios of Ugandan Waters

    NASA Astrophysics Data System (ADS)

    Gebremichael, M. G.; Jasechko, S.

    2013-12-01

    Today, 70% of the 35 million people living in Uganda have access to an improved water source, ranking Uganda 148 out of 179 nations reporting in 2010 (Millennium Development Goals Indicators). 80% of Ugandans rely on groundwater as their primary drinking water source, collecting at springs or from shallow wells. Similarly, 80% of Ugandans rely upon agriculture - usually rain fed - as their primary income source. Despite lack of access to protected water sources faced by 10 million Ugandans, and the importance of the blue economy to Uganda's continued development, a country-wide investigation of the chemistry and the stable oxygen and hydrogen isotope compositions of waters has yet to be completed. Here we present 250 analyses of 18O/16O, 2H/1H and dissolved ion concentrations of Ugandan lakes, rivers, groundwaters and springs collected during July, 2013. We use the new data to characterize regional scale groundwater recharge sources, advection pathways and interactions with surface waters. Large lakes - Albert, Edward and Victoria - show increases in 18O/16O and 2H/1H ratios consistent with open water evaporation, and are shown to be distinct from nearby groundwaters, suggesting minimal recharge from large lakes to the subsurface. Salinities of eastern Ugandan groundwaters are elevated relative to samples collected from the central and western regions, suggesting that longer groundwater residence times and enhanced water-rock interactions characterize these waters. Springs from western Uganda show a shift in 18O/16O to higher values as a result of hydrothermal water-rock exchanges. Dissolved ion and noble gas concentrations show potential for use in assessing geothermal energy resources, perhaps aiding the Ugandan Ministry for Energy, Minerals and Development to meet their goal of increasing renewable energy from 4% (current) to 61% of total use by 2017 (Nyakabwa-Atwoki, 2013). Millennium Development Goals Indicators. mdgs.un.org/unsd/mdg/data.aspx Nyakabwa

  16. Nucleon and triton production from nucleon-induced reactions on 7Li

    NASA Astrophysics Data System (ADS)

    Watanabe, Yukinobu; Guo, Hairui; Nagaoka, Kohei; Matsumoto, Takuma; Ogata, Kazuyuki; Yahiro, Masanobu

    2016-06-01

    Nucleon (N) and triton production from nucleon-induced reactions on 7Li at an incident energy of 14 MeV are analyzed by using three-body continuum discretized coupled channels method (CDCC), final state interaction (FSI) model, and sequential decay (SD) model. The CDCC is used to describe nucleon and triton production via breakup continuum channels, 7Li(N,N')7Li*→ t + α. Triton production from p(n) + 7Li → t + 5Li(5He) channel and nucleon production from sequential decay of the ground-state 5Li(5He) are calculated by the FSI model and the SD model, respectively. The calculated double differential cross sections for both nucleon and triton production are in good agreement with experimental ones except at relatively low nucleon emission energies.

  17. Light charged particles emitted in fission reactions induced by protons on 208Pb

    NASA Astrophysics Data System (ADS)

    Rodríguez-Sánchez, J. L.; Benlliure, J.; Paradela, C.; Ayyad, Y.; Casarejos, E.; Alvarez-Pol, H.; Audouin, L.; Bélier, G.; Boutoux, G.; Chatillon, A.; Cortina-Gil, D.; Gorbinet, T.; Heinz, A.; Kelić-Heil, A.; Laurent, B.; Martin, J.-F.; Pellereau, E.; Pietras, B.; Ramos, D.; Rodríguez-Tajes, C.; Rossi, D. M.; Simon, H.; Taïeb, J.; Vargas, J.; Voss, B.

    2016-09-01

    Light charged particles emitted in proton-induced fission reactions on 208Pb have been measured at different kinetic energies: 370 A ,500 A , and 650 A MeV. The experiment was performed by the SOFIA Collaboration at the GSI facilities in Darmstadt (Germany). The inverse kinematics technique was combined with a setup especially designed to measure light charged particles in coincidence with fission fragments. This measurement allowed us, for the first time, to obtain correlations between the light charged particles emitted during the fission process and the charge distributions of the fission fragments. These correlations were compared with different model calculations to assess the ground-to-saddle dynamics. The results confirm that transient and dissipative effects are required for an accurate description of the fission observables.

  18. In-medium modifications of the pipi interaction in photon-induced reactions.

    PubMed

    Messchendorp, J G; Janssen, S; Kotulla, M; Ahrens, J; Annand, J R H; Beck, R; Bloch, F; Caselotti, G; Fog, L; Hornidge, D; Krusche, B; Langgärtner, W; McGeorge, J C; MacGregor, I J D; Mengel, K; Metag, V; Novotny, R; Owens, R O; Pfeiffer, M; Sack, S; Sanderson, R; Schadmand, S

    2002-11-25

    Differential cross sections of the reactions (gamma,pi(0)pi(0)) and (gamma,pi(0)pi(+/-)) have been measured for several nuclei (1H,12C, and (nat)Pb) at an incident-photon energy of E(gamma)=400-460 MeV at the tagged-photon facility at MAMI-B using the TAPS spectrometer. A significant nuclear-mass dependence of the pipi invariant-mass distribution is found in the pi(0)pi(0) channel. This dependence is not observed in the pi(0)pi(+/-) channel and is consistent with an in-medium modification of the pipi interaction in the I=J=0 channel. The data are compared to pi-induced measurements and to calculations within a chiral-unitary approach.

  19. Infrared spectroscopic studies on reaction induced conformational changes in the NADH ubiquinone oxidoreductase (complex I).

    PubMed

    Hellwig, Petra; Kriegel, Sébastien; Friedrich, Thorsten

    2016-07-01

    Redox-dependent conformational changes are currently discussed to be a crucial part of the reaction mechanism of the respiratory complex I. Specialized difference Fourier transform infrared techniques allow the detection of side-chain movements and minute secondary structure changes. For complex I, (1)H/(2)H exchange kinetics of the amide modes revealed a better accessibility of the backbone in the presence of NADH and quinone. Interestingly, the presence of phospholipids, that is crucial for the catalytic activity of the isolated enzyme complex, changes the overall conformation. When comparing complex I samples from different species, very similar electrochemically induced FTIR difference spectra and very similar rearrangements are reported. Finally, the information obtained with variants and from Zn(2+) inhibited samples for the conformational reorganization of complex I upon electron transfer are discussed in this review. This article is part of a Special Issue entitled Respiratory complex I, edited by Volker Zickermann and Ulrich Brandt.

  20. Noise-induced convergence of the low flow rate chaos in the Belousov-Zhabotinsky reaction

    NASA Astrophysics Data System (ADS)

    Yoshimoto, Minoru; Nakaiwa, Masaru; Akiya, Takaji; Ohmori, Takao; Yamaguchi, Tomohiko

    The effect of noise on the low flow-rate chaos in the Belousov-Zhabotinsky (BZ) reaction was studied. The chaos was simulated using the three-variable model of Györgyi and Field. Gaussian white noise was imposed on the flow-rate of the reactant solutions fed into CSTR to simulate the so-called type P noise. The range of average noise amplitudes was chosen between 0.01% and 1% related to the inverse residence time. The calculated time series were analyzed on the basis of their Fourier spectra, maximum Lyapunov exponent, Kolmogorov entropies, return maps and invariant density. We found that the noise induces partial order of the period-3-like oscillations in the low flowrate chaos.

  1. Role of Background Electrolyte in Electrokinetic Locomotion by Reaction-Induced Charge Auto-Electrophoresis

    NASA Astrophysics Data System (ADS)

    Moran, Jeffrey L.; Posner, Jonathan D.

    2011-11-01

    Bimetallic particles propel themselves through aqueous solutions by harvesting chemical energy from hydrogen peroxide fuel and converting it to fluid motion through reaction-induced charge auto-electrophoresis. We present a scaling analysis and computational simulations that describe the physics underlying the locomotion of these particles. The model shows that the motion results from electrical body forces in the surrounding fluid, which are generated by a coupling of an asymmetric dipolar charge density distribution and the electric field it generates. The simulations and scaling analysis make the predictions, in agreement with experiments, that the speed of the autonomous motion depends linearly on fuel concentration and particle surface charge and inversely on solution conductivity.

  2. Functional properties of nisin-carbohydrate conjugates formed by radiation induced Maillard reaction

    NASA Astrophysics Data System (ADS)

    Muppalla, Shobita R.; Sonavale, Rahul; Chawla, Surinder P.; Sharma, Arun

    2012-12-01

    Nisin-carbohydrate conjugates were prepared by irradiating nisin either with glucose or dextran. Increase in browning and formation of intermediate products was observed with a concomitant decrease in free amino and reducing sugar groups indicating occurrence of the Maillard reaction catalyzed by irradiation. Nisin-carbohydrate conjugates showed a broad spectrum antibacterial activity against Gram negative bacteria (Escherichia coli, Pseudomonas fluorescence) as well as Gram positive bacteria (Staphylococcus aureus, Bacillus cereus). Results of antioxidant assays, including that of DPPH radical-scavenging activity and reducing power, showed that the nisin-dextran conjugates possessed better antioxidant potential than nisin-glucose conjugate. These results suggested that it was possible to enhance the functional properties of nisin by preparing radiation induced conjugates suitable for application in food industry.

  3. Analysis of the Nuclear Structure of 186 Re Using Neutron-Induced Reactions

    NASA Astrophysics Data System (ADS)

    Matters, David; McClory, John; Carroll, James; Chiara, Chris; Fotiades, Nikolaos; Devlin, Matt; Nelson, Ron O.

    2015-04-01

    Evaluated nuclear structure data for 186 Re identifies the majority of spin-parity assignments as tentative, with approximate values associated with the energies of several levels and transitions. In particular, the absence of known transitions that feed the Jπ =8+ isomer motivates their discovery, which would have astrophysical implications and a potential application in the development of an isomer power source. Using the GErmanium Array for Neutron Induced Excitations (GEANIE) spectrometer at the Los Alamos Neutron Science Center (LANSCE) Weapons Neutron Research (WNR) facility, the (n,2n γ) and (n,n' γ) reactions in a 99.52% enriched 187 Re target were used to measure γ-ray excitation functions in 186 Re and 187 Re, respectively. A preliminary analysis of the data obtained from the experiment reveals several new transitions in 186 Re and 187 Re.

  4. Neutron- and proton-induced reactions for analysis of bioenvironmental samples

    SciTech Connect

    Spyrou, N.M.; Altaf, W.J.; Khrbish, Y.S. )

    1988-01-01

    The study of the elemental composition of bioenvironmental samples is of continuing interest in a wide variety of medical and environmental investigations, be it as environmental monitors or as indicators of the state of health and disease of an individual or a population. Nuclear activation methods play an important role in these studies as research tools and in certain cases are employed as rapid, routine analytical techniques. Although the authors have been using instrumental neutron activation analysis as the main technique for obtaining information about elemental composition and concentration, they have also developed techniques, for further or complementary analysis, in which proton-induced reactions have been exploited. Two recent studies, in which the composition of human lung tissue and the elemental concentration in plant samples were determined, have been selected as illustrations of the techniques employed.

  5. Tungsten fragmentation in nuclear reactions induced by high-energy cosmic-ray protons

    SciTech Connect

    Chechenin, N. G. Chuvilskaya, T. V.; Shirokova, A. A.; Kadmenskii, A. G.

    2015-01-15

    Tungsten fragmentation arising in nuclear reactions induced by cosmic-ray protons in space-vehicle electronics is considered. In modern technologies of integrated circuits featuring a three-dimensional layered architecture, tungsten is frequently used as a material for interlayer conducting connections. Within the preequilibrium model, tungsten-fragmentation features, including the cross sections for the elastic and inelastic scattering of protons of energy between 30 and 240 MeV; the yields of isotopes and isobars; their energy, charge, and mass distributions; and recoil energy spectra, are calculated on the basis of the TALYS and EMPIRE-II-19 codes. It is shown that tungsten fragmentation affects substantially forecasts of failures of space-vehicle electronics.

  6. Cremophor-induced lupus erythematosus-like reaction with taxol administration: a case report and review of the literature.

    PubMed

    Pham, Anthony Q; Berz, David; Karwan, Patricia; Colvin, Gerald A

    2011-09-01

    We report the first case of Cremophor EL-induced cutaneous lupus erythematosus-like reaction in a 40-year-old female undergoing treatment for breast cancer. There have been four reported cases of paclitaxel- and four cases of docetaxel-induced cutaneous lupus reactions in the published literature [Dasanu and Alexandrescu: South Med J 2008;101:1161-1162; Adachi and Horikawa: J Dermatol 2007;34:473-476; Lortholary et al: Presse Med 2007;36:1207-1208; Chen et al: J Rheumatol 2004;31:818-820]. Our patient developed findings of a cutaneous lupus-like reaction with administration of paclitaxel which was subsequently discontinued. She was re-challenged with albumin-bound paclitaxel which has no Cremophor EL compound in its formulation. This administration of albumin-bound paclitaxel did not induce further reaction. She did not develop a cutaneous lupus erythematosus-like reaction with three other subsequent administrations of albumin-bound paclitaxel. The diagnosis of lupus-like reaction in our patient was made based on the development of a malar butterfly rash sparing the nasolabial folds, the appearance of this rash in context of recently receiving treatments with paclitaxel, resolution of the rash after discontinuing the paclitaxel, and the presence of autoimmune antibodies in the patient's serum which resolved with discontinuation of the paclitaxel. This is the first case demonstrating that the cause of the cutaneous lupus erythematosus-like reaction is not likely due to the taxane component of paclitaxel but the chemical composition of Cremophor EL. If the chemotherapeutic agent was causing the reaction then the same reaction should be seen by albumin-bound paclitaxel. We propose that previously reported lupus reactions may actually be due to Cremophor EL, which consists of polyoxyethylated castor oil, and not the chemotherapeutic agent itself.

  7. A Reaction-Diffusion Model of ROS-Induced ROS Release in a Mitochondrial Network

    PubMed Central

    Zhou, Lufang; Aon, Miguel A.; Almas, Tabish; Cortassa, Sonia; Winslow, Raimond L.; O'Rourke, Brian

    2010-01-01

    Loss of mitochondrial function is a fundamental determinant of cell injury and death. In heart cells under metabolic stress, we have previously described how the abrupt collapse or oscillation of the mitochondrial energy state is synchronized across the mitochondrial network by local interactions dependent upon reactive oxygen species (ROS). Here, we develop a mathematical model of ROS-induced ROS release (RIRR) based on reaction-diffusion (RD-RIRR) in one- and two-dimensional mitochondrial networks. The nodes of the RD-RIRR network are comprised of models of individual mitochondria that include a mechanism of ROS-dependent oscillation based on the interplay between ROS production, transport, and scavenging; and incorporating the tricarboxylic acid (TCA) cycle, oxidative phosphorylation, and Ca2+ handling. Local mitochondrial interaction is mediated by superoxide (O2 .−) diffusion and the O2 .−-dependent activation of an inner membrane anion channel (IMAC). In a 2D network composed of 500 mitochondria, model simulations reveal ΔΨm depolarization waves similar to those observed when isolated guinea pig cardiomyocytes are subjected to a localized laser-flash or antioxidant depletion. The sensitivity of the propagation rate of the depolarization wave to O2.− diffusion, production, and scavenging in the reaction-diffusion model is similar to that observed experimentally. In addition, we present novel experimental evidence, obtained in permeabilized cardiomyocytes, confirming that ΔΨm depolarization is mediated specifically by O2 .−. The present work demonstrates that the observed emergent macroscopic properties of the mitochondrial network can be reproduced in a reaction-diffusion model of RIRR. Moreover, the findings have uncovered a novel aspect of the synchronization mechanism, which is that clusters of mitochondria that are oscillating can entrain mitochondria that would otherwise display stable dynamics. The work identifies the fundamental mechanisms

  8. Electrochemical Impedance Spectroscopy (bio)sensing through hydrogen evolution reaction induced by gold nanoparticles.

    PubMed

    Mayorga-Martinez, Carmen C; Chamorro-Garcia, Alejandro; Merkoçi, Arben

    2015-05-15

    A new gold nanoparticle (AuNP) based detection strategy using Electrochemical Impedance Spectroscopy (EIS) through hydrogen evolution reaction (HER) is proposed. This EIS-HER method is used as an alternative to the conventional EIS based on [Fe(CN)6](3-/4-) or [Ru(NH3)6](3+/2+) indicators. The proposed method is based on the HER induced by AuNPs. EIS measurements for different amounts of AuNP are registered and the charge transfer resistance (Rct) was found to correlate and be useful for their quantification. Moreover the effect of AuNP size on electrical properties of AuNPs for HER using this sensitive technique has been investigated. Different EIS-HER signals generated in the presence of AuNPs of different sizes (2, 5, 10, 15, 20, and 50 nm) are observed, being the corresponding phenomena extendible to other nanoparticles and related catalytic reactions. This EIS-HER sensing technology is applied to a magneto-immunosandwich assay for the detection of a model protein (IgG) achieving improvements of the analytical performance in terms of a wide linear range (2-500 ng mL(-1)) with a good limit of detection (LOD) of 0.31 ng mL(-1) and high sensitivity. Moreover, with this methodology a reduction of one order of magnitude in the LOD for IgG detection, compared with a chroamperometric technique normally used was achieved.

  9. Measurement of the Amm242 neutron-induced reaction cross sections

    NASA Astrophysics Data System (ADS)

    Buckner, M. Q.; Wu, C. Y.; Henderson, R. A.; Bucher, B.; Wimer, N.; Chyzh, A.; Bredeweg, T. A.; Baramsai, B.; Couture, A.; Jandel, M.; Mosby, S.; Ullmann, J. L.; Dance Collaboration

    2017-02-01

    The neutron-induced reaction cross sections of Amm242 were measured at the Los Alamos Neutron Science Center using the Detector for Advanced Neutron-Capture Experiments array along with a compact parallel-plate avalanche counter for fission-fragment detection. A new neutron-capture cross section was determined, and the absolute scale was set according to a concurrent measurement of the well-known Amm242(n ,f ) cross section. The (n ,γ ) cross section was measured from thermal energy to an incident energy of 1 eV at which point the data quality was limited by the reaction yield in the laboratory. Our new Amm242 fission cross section was normalized to ENDF/B-VII.1 to set the absolute scale, and it agreed well with the (n ,f ) cross section reported by Browne et al. (1984) from thermal energy to 1 keV. The average absolute capture-to-fission ratio was determined from thermal energy to En=0.1 eV, and it was found to be 26(4)% as opposed to the ratio of 19 % from the ENDF/B-VII.1 evaluation.

  10. Temperature-induced gene expression associated with different thermal reaction norms for growth rate.

    PubMed

    Ellers, Jacintha; Mariën, Janine; Driessen, Gerard; van Straalen, Nico M

    2008-03-15

    Although nearly all organisms are subject to fluctuating temperature regimes in their natural habitat, little is known about the genetics underlying the response to thermal conditions, and even less about the genetic differences that cause individual variation in thermal response. Here, we aim to elucidate possible pathways involved in temperature-induced phenotypic plasticity of growth rate. Our model organism is the collembolan Orchesella cincta that occurs in a wide variety of habitats and is known to be adapted to local thermal conditions. Because sequence information is lacking in O. cincta, we constructed cDNA libraries enriched for temperature-responsive genes using suppression subtractive hybridization. We compared gene expression of O. cincta with steep thermal reaction norms (high plasticity) to those with flat thermal reaction norms (low plasticity) for juvenile growth after exposure to a temperature switch composed of a cooling or a warming treatment. Using suppression subtractive hybridization, we found differential expression of ten nuclear genes, including several genes involved in energy metabolism, such as pantothenate kinase and carbonic anhydrase. In addition, seven mitochondrial genes were found in the cloned subtracted library, but further analysis showed this was caused by allelic variation in mitochondrial genes in our founder population, and that a specific haplotype was associated with high thermal responsiveness. Future work will focus on candidate genes from pathways such as the oxidative phosphorylation and biosynthesis of coenzyme A which are possibly involved in thermal responsiveness of juvenile growth rate.

  11. Cephalosporin Induced Disulfiram-Like Reaction: A Retrospective Review of 78 Cases

    PubMed Central

    Ren, Shiyan; Cao, Yuxia; Zhang, Xiuwei; Jiao, Shichen; Qian, Songyi; Liu, Peng

    2014-01-01

    Concomitant ingestion of alcohol and cephalosporin may cause a disulfiram-like reaction; however its fatal outcomes are not commonly known. We retrospectively reviewed 78 patients who had cephalosporin induced disulfiram-like reaction (CIDLR). The patients who had a negative skin test to cephalosporin prior to intravenous antibiotics were included, and those who were allergic to either alcohol or antibiotics were excluded. The average age of 78 patients was 37.8±12.2 (21–60) years. Of the 78 patients, 93.58% of the patients were males, 70.51% of the patients consumed alcohol after use of antibiotics, and 29.49% patients consumed alcohol initially, followed by intravenous antibiotics; however, no significant difference of morbidity was observed in these two groups. All patients were administered antibiotics intravenously. Five of 78 patients (6.41%) developed severe CIDLR too urgently to be rescued successfully. In conclusion, it is important for clinicians to educate patients that no alcohol should be used if one is taking cephalosporin. Also, clinicians should keep in mind that cephalosporin should not be prescribed for any alcoholics. PMID:24670024

  12. Supramolecular substitution reactions between hydrazide-based molecular duplex strands: complexation induced nonsymmetry and dynamic behavior.

    PubMed

    Yang, Yong; Xiang, Jun-Feng; Xue, Min; Hu, Hai-Yu; Chen, Chuan-Feng

    2008-08-15

    Supramolecular substitution reactions between hydrazide-based oligomers 1a- c and 2a- c were systematically investigated. Each oligomer existed as hydrogen-bonding mediated molecular duplex strands or a polymeric zipper structure in apolar solvents. But when another oligomer with complementary hydrogen bonding sites was added, a heterodimer structure formed due to supramolecular substitution reaction driven by the formation of more hydrogen bonds, which was evidenced by NMR experiments, sometimes gel-sol transition. When a nonsymmetric oligomer and a symmetric oligomer were involved, complexation-induced nonsymmetry was observed. When two nonsymmetric oligomers were involved, two hydrogen-bonded isomers were observed in solution. Variable-temperature (1)H NMR experiments further revealed unique dynamic behavior for the individual oligomer and the complexes. When diacetyl-terminated oligomer 1c was involved, slides perpendicular to hydrogen bonds between two constituent molecules were observed, which led to complicated (1)H NMR spectra at lower temperature; otherwise, high selectivity was obtained. Combined with the results we reported previously, a detailed picture of the structure-property relationship for our hydrazide-based oligomers was depicted, which would provide guidelines for the design of hydrazide-based fine-tuning functional materials.

  13. Measurement of the Am242m neutron-induced reaction cross sections

    DOE PAGES

    Buckner, M. Q.; Wu, C. Y.; Henderson, R. A.; ...

    2017-02-17

    The neutron-induced reaction cross sections of 242mAm were measured at the Los Alamos Neutron Science Center using the Detector for Advanced Neutron-Capture Experiments array along with a compact parallel-plate avalanche counter for fission-fragment detection. A new neutron-capture cross section was determined, and the absolute scale was set according to a concurrent measurement of the well-known 242mAm(n,f) cross section. The (n,γ) cross section was measured from thermal energy to an incident energy of 1 eV at which point the data quality was limited by the reaction yield in the laboratory. Our new 242mAm fission cross section was normalized to ENDF/B-VII.1 tomore » set the absolute scale, and it agreed well with the (n,f) cross section from thermal energy to 1 keV. Lastly, the average absolute capture-to-fission ratio was determined from thermal energy to En = 0.1 eV, and it was found to be 26(4)% as opposed to the ratio of 19% from the ENDF/B-VII.1 evaluation.« less

  14. The Modulatory Effect of Ischemia and Reperfusion on Arginine Vasopressin-Induced Arterial Reactions.

    PubMed

    Szadujkis-Szadurska, Katarzyna; Malinowski, Bartosz; Piotrowska, Małgorzata; Grześk, Grzegorz; Wiciński, Michał; Gajdus, Marta

    2016-01-01

    Aim of the Study. The purpose of this study was to investigate the impact of ischemia and reperfusion on the resistance of arteries to AVP (arginine vasopressin), with a particular emphasis on the role of smooth muscle cells in the action of vasopressin receptors and the role of the cGMP-associated signalling pathway. Materials and Methods. Experiment was performed on the perfunded tail arteries from male Wistar rats. The constriction triggered by AVP after 30 minutes of ischemia and 30 and 90 minutes of reperfusion was analysed. Analogous experiments were also carried out in the presence of 8Br-cGMP. Results. Ischemia reduces and reperfusion increases in a time-dependent manner the arterial reaction to AVP. The presence of 8Br-cGMP causes a significant decrease of arterial reactivity under study conditions. Conclusions. Ischemia and reperfusion modulate arterial contraction triggered by AVP. The effect of 8Br-cGMP on reactions, induced by AVP after ischemia and reperfusion, indicates that signalling pathway associated with nitric oxide (NO) and cGMP regulates the tension of the vascular smooth muscle cells.

  15. Microglial reaction in focal cerebral ischaemia induced by intra-carotid homologous clot injection.

    PubMed

    Ng, Y K; Ling, E A

    2001-01-01

    This study examined the microglial reaction in a simulated thrombo-embolus ischaemia in rats given an intracarotid injection of a suspension of homologous blood clot. All rats including the controls receiving vehicle injection were perfused at 5 hours, and 1, 3 and 7 days post-operation. The brains were removed and processed for immunohistochemistry using a panel of monoclonal antibodies: OX-42, OX-18 and OX-6 for labeling of microglia. In rats given saline injection OX-42 immunoreactive microglial cells were observed to be distributed quite evenly throughout the whole brain. When injection of clot suspension was given, microglial cells responded vigorously, particularly in the ipsilateral hippocampus. Microglial reaction was also detected in the ipsilateral cerebral cortex, caudate as well as septal nuclei. The majority of the detected reactive microglial cells were hypertrophied showing thick or stout processes. Some rod-like and amoeboid microglia were also observed. Rarely did the reactive microglia express OX-6 immunoreactivity. All microglial cells were unreactive for OX-18. The actual mechanisms leading to the microglial activation as well as functions of reactive microglia in focal cerebral ischaemia remain speculative. In the absence of direct evidence, it could only be suggested that they may act as sensor cells for detection of subtle alterations in the microenvironment, probably in response to focal ischaemia and/or leakage of serum-derived factors induced by thrombo-embolus stroke.

  16. Drug-reaction eosinophilia and systemic symptoms and drug-induced hypersensitivity syndrome.

    PubMed

    Fernando, Suran L

    2014-02-01

    Drug reaction with eosinophilia and systemic symptoms (DRESS), also known as drug-induced hypersensitivity syndrome (DIHS), is a rare, severe cutaneous adverse reaction characterised by fever, rash, lymphadenopathy, eosinophilia and/or other leukocyte abnormalities, and internal organ involvement and often has a relapsing-remitting course despite withdrawal of the drug. The drugs that are most implicated include aromatic anticonvulsants, allopurinol, sulphonamides, antiretrovirals (abacavir and nevirapine), and minocycline. The pathogenesis of DRESS/DIHS is far from clear but probably involves a combination of impaired pharmacokinetics and the accumulation of drug metabolites, the sequential reactivation of the herpesvirus family and genetic susceptibility conferred by the association with certain human leukocyte antigen (HLA) class I alleles. The strong association between abacavir and HLA-B*5701 has enabled pharmacogenetics screening to be employed successfully to minimise the occurrence of hypersensitivity. A prolonged course of oral corticosteroids is required to treat DRESS/DIHS, given the relapsing-remitting nature of the condition with i.v. immunoglobulin and valgangciclovir reserved for refractory or life-threatening cases.

  17. The Modulatory Effect of Ischemia and Reperfusion on Arginine Vasopressin-Induced Arterial Reactions

    PubMed Central

    Malinowski, Bartosz; Piotrowska, Małgorzata; Grześk, Grzegorz; Gajdus, Marta

    2016-01-01

    Aim of the Study. The purpose of this study was to investigate the impact of ischemia and reperfusion on the resistance of arteries to AVP (arginine vasopressin), with a particular emphasis on the role of smooth muscle cells in the action of vasopressin receptors and the role of the cGMP-associated signalling pathway. Materials and Methods. Experiment was performed on the perfunded tail arteries from male Wistar rats. The constriction triggered by AVP after 30 minutes of ischemia and 30 and 90 minutes of reperfusion was analysed. Analogous experiments were also carried out in the presence of 8Br-cGMP. Results. Ischemia reduces and reperfusion increases in a time-dependent manner the arterial reaction to AVP. The presence of 8Br-cGMP causes a significant decrease of arterial reactivity under study conditions. Conclusions. Ischemia and reperfusion modulate arterial contraction triggered by AVP. The effect of 8Br-cGMP on reactions, induced by AVP after ischemia and reperfusion, indicates that signalling pathway associated with nitric oxide (NO) and cGMP regulates the tension of the vascular smooth muscle cells. PMID:27563664

  18. Lectin staining and flow cytometry reveals female-induced sperm acrosome reaction and surface carbohydrate reorganization

    PubMed Central

    Kekäläinen, Jukka; Larma, Irma; Linden, Matthew; Evans, Jonathan P.

    2015-01-01

    All cells are covered by glycans, an individually unique layer of oligo- and polysaccharides that are critical moderators of self-recognition and other cellular-level interactions (e.g. fertilization). The functional similarity between these processes suggests that gamete surface glycans may also have an important, but currently overlooked, role in sexual selection. Here we develop a user-friendly methodological approach designed to facilitate future tests of this possibility. Our proposed method is based on flow cytometric quantification of female-induced sperm acrosome reaction and sperm surface glycan modifications in the Mediterranean mussel Mytilus galloprovincialis. In this species, as with many other taxa, eggs release water-soluble factors that attract conspecific sperm (chemoattraction) and promote potentially measurable changes in sperm behavior and physiology. We demonstrate that flow cytometry is able to identify sperm from other seawater particles as well as accurately measure both acrosome reaction and structural modifications in sperm glycans. This methodological approach can increase our understanding of chemically-moderated gamete-level interactions and individual-specific gamete recognition in Mytilus sp. and other taxa with similar, easily identifiable acrosome structure. Our approach is also likely to be applicable to several other species, since carbohydrate-mediated cellular-level interactions between gametes are universal among externally and internally fertilizing species. PMID:26470849

  19. Enhancing the branching ratios in the dissociation channels for O{sup 16}O{sup 16}O{sup 18} molecule by designing optimum laser pulses: A study using stochastic optimization

    SciTech Connect

    Talukder, Srijeeta; Chaudhury, Pinaki; Sen, Shrabani; Sharma, Rahul; Adhikari, Satrajit

    2015-10-14

    We propose a strategy of using a stochastic optimization technique, namely, simulated annealing to design optimum laser pulses (both IR and UV) to achieve greater fluxes along the two dissociating channels (O{sup 18} + O{sup 16}O{sup 16} and O{sup 16} + O{sup 16}O{sup 18}) in O{sup 16}O{sup 16}O{sup 18} molecule. We show that the integrated fluxes obtained along the targeted dissociating channel is larger with the optimized pulse than with the unoptimized one. The flux ratios are also more impressive with the optimized pulse than with the unoptimized one. We also look at the evolution contours of the wavefunctions along the two channels with time after the actions of both the IR and UV pulses and compare the profiles for unoptimized (initial) and optimized fields for better understanding the results that we achieve. We also report the pulse parameters obtained as well as the final shapes they take.

  20. The D/H and ^18^O/^16^O ratios in water from comet P/Halley.

    NASA Astrophysics Data System (ADS)

    Eberhardt, P.; Reber, M.; Krankowsky, D.; Hodges, R. R.

    1995-10-01

    From a detailed evaluation of the ion currents measured by the Neutral Mass Spectrometer (NMS) on the Giotto spaceprobe in the 17.5amu/e to 21.5amu/e mass range inside the contact surface of P/Halley we derive the cometary ion densities for masses 18amu/e to 21amu/e. From these we calculate the deuterium and ^18^O abundances in the H_3_O^+^ ion to be (D/H)_H_3_O^+^_=(2.55+/-0.18)x10^-4^ and ^18^O/^16^O=(2.13+/-0.18)x10^-3^. The errors are 3σ-errors of the means of eight measurements at different distances. These results are in agreement with the preliminary evaluation (Eberhardt et al. 1987a) but the errors are considerably smaller. In a detailed discussion we show that for deuterium the isotope fractionation between the H_3_O^+^ ion and the H_2_O gas in the coma is not negligible, mainly due to the isotope exchange reaction H_3_O^+^+HDO<->H_2_DO^+^+H_2_O. Based on extensive calculations we obtain for the deuterium abundance in the water of the coma (D/H)_H_2_O_=(3.02+/-0.22)x10^-4^. We show that no significant D/H fractionation between the H_2_O in the coma and the ice in the nucleus is expected. We also apply our fractionation correction to the D/H determination in the H_3_O^+^ ion based on the measurements of the Ion Mass Spectrometer (IMS) (Balsiger et al. 1995) which agree within errors with our results. From the independent results of the NMS and IMS we obtain as best value for the isotopic composition in the H_2_O and H_2_O-ice of P/Halley the values (D/H)_H_2_O_=(3.16+/-0.34)x10^-4^ and (^18^O/^16^O)_H_2_O_=(2.03+/-0.15)x10^-3^. The oxygen isotopic composition in P/Halley is identical with the average solar system value. Deuterium in P/Halley's water is enriched by a factor of 12 relative to the protosolar D/H ratio and by a factor of 2 relative to the terrestrial D/H. We show that this strong deuterium enrichment cannot be explained by processes in the solar nebula such as the H_2_O+HD<->HDO+H_2_ isotope exchange reaction. The deuterium enrichment in P

  1. The roles of fluid transport and surface reaction in reaction-induced fracturing, with implications for the development of mesh textures in serpentinites

    NASA Astrophysics Data System (ADS)

    Shimizu, Hiroyuki; Okamoto, Atsushi

    2016-09-01

    The distinct element method was used to simulate chemical-mechanical-hydraulic processes that occur during serpentinization (volume-increasing hydration) within the oceanic lithosphere. The proposed model considers water transported in two ways: advective flow along fractures and through matrices. Variations in fracture pattern and system evolution were examined using two nondimensional parameters: the ratios of the rates of flow in fracture ( Ψ F) and matrix ( Ψ M) to the surface reaction rate. In cases of fixed Ψ F and Ψ M with sufficiently low reaction rates, the fracture pattern is not dependent on the surface reaction rate. Otherwise, the fracture pattern varies systematically as a function of Ψ F and Ψ M. At low Ψ F (≤1) and low Ψ M (≤1), the reaction proceeds from the boundaries inward and forms fine fractures layer by layer. At high Ψ F (≥10,000) and low Ψ M (≤10), the reaction proceeds from the boundaries inward and forms polygonal fracture networks. As Ψ M increases (>100), the reaction tends to proceed homogeneously from the boundaries without fracturing. A comparison of natural and simulated textures reveals that the following conditions are necessary to develop mesh textures during serpentinization in the oceanic lithosphere. (1) The surface reaction rate must be similar to or higher than the fluid flow rate in the matrix (or than the diffusive transport of water), and much lower than the fluid flow rate along fractures. (2) Original olivine grain boundaries act as pathways for fluid transport; these pathways may result from thermal or tectonic stress-induced cracking prior to serpentinization.

  2. Investigations of nuclear structure and nuclear reactions induced by complex projectiles

    SciTech Connect

    Sarantites, D.G.

    1990-01-01

    This report discusses research in the following areas: nuclear structure; fusion reactions near and below the barrier; incomplete fusion and fragmentation reactions; and instrumentation and analysis. (LSP).

  3. Revised Production Rates for Na-22 and Mn-54 in Meteorites Using Cross Sections Measured for Neutron-induced Reactions

    NASA Technical Reports Server (NTRS)

    Sisterson, J. M.; Kim, K. J.; Reedy, R. C.

    2004-01-01

    The interactions of galactic cosmic rays (GCR) with extraterrestrial bodies produce small amounts of radionuclides and stable isotopes. The production rates of many relatively short-lived radionuclides, including 2.6-year Na-22 and 312-day Mn-54, have been measured in several meteorites collected very soon after they fell. Theoretical models used to calculate production rates for comparison with the measured values rely on input data containing good cross section measurements for all relevant reactions. Most GCR particles are protons, but secondary neutrons make most cosmogenic nuclides. Calculated production rates using only cross sections for proton-induced reactions do not agree well with measurements. One possible explanation is that the contribution to the production rate from reactions initiated by secondary neutrons produced in primary GCR interactions should be included explicitly. This, however, is difficult to do because so few of the relevant cross sections for neutron-induced reactions have been measured.

  4. Fluorescence observations of LDEF exposed materials as an indicator of induced material reactions

    NASA Technical Reports Server (NTRS)

    Linton, Roger C.; Whitaker, Ann F.; Kamenetzky, Rachel R.

    1993-01-01

    Observations and measurements of induced changes in the fluorescent emission of materials exposed to the space environment on the Long Duration Exposure Facility (LDEF) have revealed systematic patterns of material-dependent behavior. These results have been supplemented by inspection of similar materials exposed on previous Space Shuttle Missions and in laboratory testing. The space environmental factors affecting the fluorescence of exposed materials have been found to include (but are not necessarily limited to) solar ultraviolet (UV) radiation, atomic oxygen (AO), thermal vacuum exposure, and synergistic combinations of these factors. Observed changes in material fluorescent behavior include stimulation, quenching, and spectral band shifts of emission. For example, the intrinsic yellow fluorescence of zinc oxide pigmented thermal control coatings undergoes quenching as a result of exposure, while coloration is stimulated in the fluorescent emission of several polyurethane coating materials. The changes in fluorescent behavior of these materials are shown to be a revealing indicator of induced material reactions as a result of space environmental exposure.

  5. Stirring-induced bifurcation driven by the chaotic regime in the Belousov—Zhabotinsky reaction in a CSTR

    NASA Astrophysics Data System (ADS)

    Strizhak, Peter E.

    1995-09-01

    The stirring-induced bifurcation at low stirring rate S 0 = 23 rpm of the reaction volume has been observed for the chaotic regime in the Belousov—Zhabotinsky oscillating chemical reaction (malonic acidbromatecerium(III)sulfuric acid) in a continuously stirred tank reactor in premixing mode. This bifurcation is characterized by a stepwise growth of the macroscopic spatial concentration gradients that is shown by the use of the time dependencies of the potential difference between two platinum electrodes.

  6. Trojan Horse Method for the Oxygen-Burning Process Reactions

    NASA Astrophysics Data System (ADS)

    Hayakawa, S.; Spitaleri, C.; Burtebayev, N.; Aimaganbetov, A.; Artemov, S. V.; Figuera, P.; Fisichella, M.; Guardo, G. L.; Igamov, S.; Indelicato, I.; Kiss, G. G.; Kubono, S.; La Cognata, M.; Lamia, L.; Lattuada, M.; Nassurlla, M.; Piasecki, E.; Rapisarda, G. G.; Romano, S.; Sakuta, S. B.; TrzciÅska, A.; Tumino, A.; Urkinbayev, A.; Zholdybayev, T.

    The 16O + 16O fusion reaction is important in terms of the explosive oxygen burning process during late evolution stage of massive stars as well as understanding of the mechanism of low-energy heavy-ion fusion reactions. The astrophysical S factor of such a heavy-ion fusion strongly depends on energy at corresponding stellar temperatures. For the 16O + 16O reaction cross section, there are larger discrepancies among different experimental data as the energy decreases, and a complete lack of data below Ec.m. = 7 MeV. We aim to determine the cross sections for the two main exit channels, α + 28Si and p + 31P, toward stellar energies. The measurements were performed indirectly by the Trojan horse method (THM) via the 16O(20Ne, α α )28Si and 16O(20Ne, pα )31P three-body reactions, respectively. We performed measurements twice using 20Ne beams at Heavy Ion Laboratory (E20Ne = 45 MeV) and at Gumilyov Eurasian National University (E20Ne = 35 MeV). We discuss the applicability of the THM to such a heavy nuclear system showing preliminary results of the momentum distribution of α -16O intercluster motion in the TH nucleus 20Ne observed for the first time, which implies a possibility of a multi-step breakup of the TH nucleus.

  7. Correlation of Vascular Endothelial Growth Factor Production with Photochemical Reaction-induced Retinal Edema

    PubMed Central

    Shan, Liang; Zheng, Mi; Zhang, Yuan; Qu, Yuan; Niu, Tian; Gu, Qing; Liu, Kun; Xia, Xin

    2016-01-01

    Background: Retinal edema is the major complication of retinal vein occlusion and diabetic retinopathy; it can damage visual function by influencing macular region. This study was to establish a rat retinal edema model and explore the related VEGF expression and observe the responses to anti-VEGF drugs in this model. Methods: A rat retinal edema model was established by inducing photochemical reaction using a 532 nm laser after the intravenous injection of Erythrosin B. Immediately after the laser treatment, models were given intravitreal injections of Ranibizumab or Conbercept to inhibit VEGF expression, and the changes of retinal thickness were measured. Retinal edema was observed using fundus photography (FP), optical coherence tomography (OCT), and fluoresce in fundus angiography (FFA) at 0, 1, 2, 4, 7 and 14 days after intervention. The retinal VEGF expression was measured using enzyme-linked immunosorbent assay (ELISA) and western blotting at each time point. The rat retinal edema model was also used to verify the function of anti-VEGF polypeptide ZY1. Results: Both retinal edema and vascular leakage were clearly observed at 1, 2 and 4 days after photochemical induction and the retinal thickness increased notably over the same period. The retinal VEGF expression peaked at day 1 and retina became thickening simultaneously. After the interventions, the VEGF expression of the Ranibizumab and Conbercept groups decreased at each time point compared to the edema group (26.90 ± 3.57 vs. 40.29 ± 6.68, F = 31.269 on day 1 and 22.36 ± 1.12 vs. 29.92 ± 0.93 F = 163.789 on day 2, both P < 0.01); the mean RT (278 ± 4 vs. 288 ± 3, F = 134.190 on day 1 and 274 ± 7 vs. 284 ± 6, F = 64.367 on day 2, both P < 0.05) and vascular leakage in these groups also decreased. The same results were observed in the ZY1 group, particularly at day 2 (P < 0.05). Conclusions: This retinal edema model induced by a photochemical reaction is reliable and repeatable. Induced edema

  8. Indirect determination of Li via 74Ge(n,γ)75mGe activation reaction induced by neutrons from 7Li(p,n)7Be reaction

    NASA Astrophysics Data System (ADS)

    Kumar, Sanjiv; Reddy, G. L. N.; Rao, Pritty; Verma, Rakesh; Ramana, J. V.; Vikramkumar, S.; Raju, V. S.

    2012-03-01

    An indirect method to determine Li by 74Ge(n,γ)75mGe activation reaction induced in a high purity Ge (detector) crystal by neutrons from the 7Li(p,n)7Be reaction in a typical particle-induced γ-ray emission (PIGE) spectroscopy experimental set-up is described. Performed with proton beams of energies in excess of 1.88 MeV, the threshold energy (Eth) of the 7Li(p,n)7Be reaction, the determination involves the activity measurement of 75mGe isotope that has a half-life of 47.7 s and decays with the emission of 139 keV γ-rays. Rapidity, selectivity and sensitivity down to ppm levels are the attractive features of the method. It is a suitable alternative to 7Li(p,p'γ)7Li reaction based PIGE technique in the analyses of matrices that contain light elements such as Be, B, F, Na and Al in significant proportions. Interferences can arise from elements, for example V and Ti, that have Eth ⩽ 1.88 MeV for (p,n) reaction. In the case of elements such as Cu, Mo which have with Eth > 1.88 MeV, the incident proton beam energy can be judiciously selected to avoid or minimize an interference. The method, under optimized irradiation conditions, does not entail a risk of neutron stimulated degradation of the performance of the detector. Besides analytical purposes, the measurement of the 75mGe activity can serve as a powerful tool to monitor even low (˜25 n/cm2 s) thermal neutron fluxes.

  9. A Biomolecule-Compatible Visible Light-Induced Azide Reduction from a DNA-Encoded Reaction Discovery System

    PubMed Central

    Chen, Yiyun; Kamlet, Adam S.; Steinman, Jonathan B.; Liu, David R.

    2010-01-01

    Using a system that accelerates the serendipitous discovery of new reactions by evaluating hundreds of DNA-encoded substrate combinations in a single experiment, we explored a broad range of reaction conditions for new bond-forming reactions. We discovered reactivity that led to a biomolecule-compatible, Ru(II)-catalyzed, visible light-induced azide reduction reaction. In contrast with current azide reduction methods, this reaction is highly chemoselective and is compatible with alcohols, phenols, acids, alkenes, alkynes, aldehydes, alkyl halides, alkyl mesylates, and disulfides. The remarkable functional group compatibility and mild conditions of this reaction enabled azide reduction to be performed on nucleic acid and oligosaccharide substrates without the detectable occurrence of side reactions. The reaction was also performed in the presence of a protein enzyme without loss of enzymatic activity, in contrast with two commonly used azide reduction methods. The visible light dependence of this reaction provides a means of photouncaging functional groups such as amines and carboxylates on biological macromolecules without using UV irradiation. PMID:21258388

  10. Cross Sections for Neutron-induced Reactions on Actinide Targets Extracted from Surrogate Experiments: A Status Report

    SciTech Connect

    Escher, J E; Burke, J T; Dietrich, F S; Lesher, S R; Scielzo, N D; Thompson, I J; Younes, W

    2009-10-01

    The Surrogate nuclear reactions method, an indirect approach for determining cross sections for compound-nuclear reactions involving difficult-to-measure targets, is reviewed. Focusing on cross sections for neutron-induced reactions on actinides, we review the successes of past and present applications of the method and assess its uncertainties and limitations. The approximations used in the analyses of most experiments work reasonably well for (n,f) cross sections for neutron energies above 1-2 MeV, but lead to discrepancies for low-energy (n,f) reactions, as well as for (n,{gamma}) applications. Correcting for some of the effects neglected in the approximate analyses leads to improved (n,f) results. We outline steps that will further improve the accuracy and reliability of the Surrogate method and extend its applicability to reactions that cannot be approached with the present implementation of the method.

  11. Sulfated polysaccharides from the egg jelly layer are species-specific inducers of acrosomal reaction in sperms of sea urchins.

    PubMed

    Alves, A P; Mulloy, B; Diniz, J A; Mourão, P A

    1997-03-14

    We have characterized the fine structure of sulfated polysaccharides from the egg jelly layer of three species of sea urchins and tested the ability of these purified polysaccharides to induce the acrosome reaction in spermatozoa. The sea urchin Echinometra lucunter contains a homopolymer of 2-sulfated, 3-linked alpha-L-galactan. The species Arbacia lixula and Lytechinus variegatus contain linear sulfated alpha-L-fucans with regular tetrasaccharide repeating units. Each of these sulfated polysaccharides induces the acrosome reaction in conspecific but not in heterospecific spermatozoa. These results demonstrate that species specificity of fertilization in sea urchins depends in part on the fine structure of egg jelly sulfated polysaccharide.

  12. A new mathematical model to simulate AVA cold-induced vasodilation reaction to local cooling.

    PubMed

    Rida, Mohamad; Karaki, Wafaa; Ghaddar, Nesreen; Ghali, Kamel; Hoballah, Jamal

    2014-11-01

    The purpose of this work was to integrate a new mathematical model with a bioheat model, based on physiology and first principles, to predict thermoregulatory arterio-venous anastomoses (AVA) and cold-induced vasodilation (CIVD) reaction to local cooling. The transient energy balance equations of body segments constrained by thermoregulatory controls were solved numerically to predict segmental core and skin temperatures, and arterial blood flow for given metabolic rate and environmental conditions. Two similar AVA-CIVD mechanisms were incorporated. The first was activated during drop in local skin temperature (<32 °C). The second mechanism was activated at a minimum finger skin temperature, T(CIVD, min), where the AVA flow is dilated and constricted once the skin temperature reached a maximum value. The value of T(CIVD,min) was determined empirically from values reported in literature for hand immersions in cold fluid. When compared with published data, the model predicted accurately the onset time of CIVD at 25 min and T(CIVD,min) at 10 °C for hand exposure to still air at 0 °C. Good agreement was also obtained between predicted finger skin temperature and experimentally published values for repeated immersion in cold water at environmental conditions of 30, 25, and 20 °C. The CIVD thermal response was found related to core body temperature, finger skin temperature, and initial finger sensible heat loss rate upon exposure to cold fluid. The model captured central and local stimulations of the CIVD and accommodated observed variability reported in literature of onset time of CIVD reaction and T(CIVD,min).

  13. Study of the 17O(n, α )14C Reaction: Extension of the Trojan Horse Method to the Neutrons Induced Reactions

    NASA Astrophysics Data System (ADS)

    Guardo, G. L.; Spitaleri, C.; Lamia, L.; Gulino, M.; Tang, X.; Bucher, B.; Burjan, V.; Couder, M.; Davies, P.; deBoer, R.; Fang, X.; Kroha, V.; La Cognata, M.; Ma, C.; Mrazek, J.; Mukhamedzhanov, A.; Notani, M.; Obrien, S.; Pizzone, R. G.; Rapisarda, G. G.; Roberson, D.; Sergi, M. L.; Tan, W.; Wiescher, M.

    The experimental study of the 17O(n, α )14C reaction has been performed in the energy range 0-350 keV. This reaction could play an important role in explaining heavy elements (s-process) nucleosynthesis in various astrophysical scenario. To overcome the practical problems arising from the neutrons production, a new application of the Trojan Horse Method has been recently suggested. In more details, the 17O(n, α )14C reaction has been studied using the quasi-free 2H(17O, α 14C)1H reaction, induced at an energy of 43.5 MeV. The measurement allows one to investigate the ℓ = 3, 75 keV resonance (E* = 8.125 MeV, Jπ = 5-), absent in the available direct measurements because of centrifugal suppression effects. Moreover, the results show that the contribution of the 166 and 236 keV resonances is in energy agreement with the available direct data. A clear contribution of the -7 keV subthreshold level is also present.

  14. Evidence for a dynamically refracted primary bow in weakly bound 9Be rainbow scattering from 16O

    NASA Astrophysics Data System (ADS)

    Ohkubo, S.; Hirabayashi, Y.

    2016-09-01

    We present for the first time evidence for the existence of a dynamically refracted primary bow for 9Be+16O scattering. This is demonstrated through the use of coupled channel calculations with an extended double folding potential derived from the density-dependent effective two-body force and precise microscopic cluster wave functions for 9Be. The calculations reproduce the experimental Airy structure in 9Be+16O scattering well. It is found that coupling of a weakly bound 9Be nucleus to excited states plays the role of a booster lens, dynamically enhancing the refraction over the static refraction due to the Luneburg lens mean field potential between the ground states of 9Be and 16O.

  15. Ginger for Prevention of Antituberculosis-induced Gastrointestinal Adverse Reactions Including Hepatotoxicity: A Randomized Pilot Clinical Trial.

    PubMed

    Emrani, Zahra; Shojaei, Esphandiar; Khalili, Hossein

    2016-06-01

    In this study, the potential benefits of ginger in preventing antituberculosis drug-induced gastrointestinal adverse reactions including hepatotoxicity have been evaluated in patients with tuberculosis. Patients in the ginger and placebo groups (30 patients in each group) received either 500 mg ginger (Zintoma)(®) or placebo one-half hour before each daily dose of antituberculosis drugs for 4 weeks. Patients' gastrointestinal complaints (nausea, vomiting, dyspepsia, and abdominal pain) and antituberculosis drug-induced hepatotoxicity were recorded during the study period. In this cohort, nausea was the most common antituberculosis drug-induced gastrointestinal adverse reactions. Forty eight (80%) patients experienced nausea. Nausea was more common in the placebo than the ginger group [27 (90%) vs 21 (70%), respectively, p = 0.05]. During the study period, 16 (26.7%) patients experienced antituberculosis drug-induced hepatotoxicity. Patients in the ginger group experienced less, but not statistically significant, antituberculosis drug-induced hepatotoxicity than the placebo group (16.7% vs 36.7%, respectively, p = 0.07). In conclusion, ginger may be a potential option for prevention of antituberculosis drug-induced gastrointestinal adverse reactions including hepatotoxicity. Copyright © 2016 John Wiley & Sons, Ltd.

  16. Radiation-Induced Chemical Reactions in Hydrogel of Hydroxypropyl Cellulose (HPC): A Pulse Radiolysis Study.

    PubMed

    Yamashita, Shinichi; Ma, Jun; Marignier, Jean-Louis; Hiroki, Akihiro; Taguchi, Mitsumasa; Mostafavi, Mehran; Katsumura, Yosuke

    2016-12-01

    We performed studies on pulse radiolysis of highly transparent and shape-stable hydrogels of hydroxypropyl cellulose (HPC) that were prepared using a radiation-crosslinking technique. Several fundamental aspects of radiation-induced chemical reactions in the hydrogels were investigated. With radiation doses less than 1 kGy, degradation of the HPC matrix was not observed. The rate constants of the HPC composing the matrix, with two water decomposition radicals [hydroxyl radical ((•)OH) and hydrated electron ([Formula: see text])] in the gels, were determined to be 4.5 × 10(9) and 1.8 × 10(7) M(-1) s(-1), respectively. Direct ionization of HPC in the matrix slightly increased the initial yield of [Formula: see text], but the additionally produced amount of [Formula: see text] disappeared immediately within 200 ps, indicating fast recombination of [Formula: see text] with hole radicals on HPC or on surrounding hydration water molecules. Reactions of [Formula: see text] with nitrous oxide (N2O) and nitromethane (CH3NO2) were also examined. Decay of [Formula: see text] due to scavenging by N2O and CH3NO2 were both slower in hydrogels than in aqueous solutions, showing slower diffusions of the reactants in the gel matrix. The degree of decrease in the decay rate was more effective for N2O than for CH3NO2, revealing lower solubility of N2O in gel than in water. It is known that in viscous solvents, such as ethylene glycol, CH3NO2 exhibits a transient effect, which is a fast reaction over the contact distance of reactants and occurs without diffusions of reactants. However, such an effect was not observed in the hydrogel used in the current study. In addition, the initial yield of [Formula: see text], which is affected by the amount of the scavenged precursor of [Formula: see text], in hydrogel containing N2O was slightly higher than that in water containing N2O, and the same tendency was found for CH3NO2.

  17. Resonant structures in heavy-ion reactions

    SciTech Connect

    Sanders, S.J.; Henning, W.; Ernst, H.; Geesaman, D.F.; Jachcinski, C.; Kovar, D.G.; Paul, M.; Schiffer, J.P.

    1980-01-01

    An investigation of heavy-ion resonance structures using the /sup 24/Mg(/sup 16/O, /sup 12/C)/sup 28/Si reaction is presented. The data are analyzed in the context of Breit-Wigner resonances added to a direct-reaction background.

  18. Mediator profiles in tears during the conjunctival response induced by allergic reaction in the nasal mucosa

    PubMed Central

    2013-01-01

    Background The allergic reaction occurring primarily in the nasal mucosa can induce a secondary conjunctival response of an immediate (SICR), late (SLCR), or delayed (SDYCR) type in some patients with allergic conjunctivitis (AC). Objectives To investigate the concentration changes of histamine, tryptase, eosinophil cationic protein (ECP), eosinophil-derived neurotoxin (EDN), leukotrienes (LTB 4, LTC4, LTE4), myeloperoxidase (MPO), interferon-γ (IFN-γ), and interleukins (IL-2, IL-4, IL-5) in tears during the SICR, SLCR, and SDYCR. Methods In 32 patients with AC, 11 SICR (p<0.01), 13 SLCR (p<0.001), and eight SDYCR (p<0.01) to nasal challenges with allergens (NPTs), the NPTs and 32 control tests with PBS were repeated and supplemented with the determination of these factors in tears. Results The SICRs were associated with significant concentration changes in tears (p<0.05) of histamine, tryptase, ECP, LTC4, and IL-4. The SLCRs were accompanied by significant changes in concentrations of histamine, ECP, LTB4, LTC4, MPO, IL-4, and IL-5. The SDYCRs were associated with significant concentration changes in tears (p<0.05) of LTB4, MPO, IFN-γ, and IL-2. No significant changes in these factors were recorded in tears during the 32 PBS controls (p>0.1) or in the ten control patients (p>0.1). Conclusions These results provide evidence for causal involvement of nasal allergy in some patients with AC, inducing secondary conjunctival response of immediate (SICR), late SLCR, or delayed SDYCR type, associated with different mediator, cytokine, and cellular profiles in the tears, suggesting involvement of different hypersensitivity mechanisms. These results also emphasize the diagnostic value of nasal allergen challenge combined with monitoring of the conjunctival response in some patients with AC. PMID:23869165

  19. The Fusarium toxin deoxynivalenol (DON) modulates the LPS induced acute phase reaction in pigs.

    PubMed

    Dänicke, Sven; Brosig, Bianca; Kersten, Susanne; Kluess, Jeannette; Kahlert, Stefan; Panther, Patricia; Diesing, Anne-Kathrin; Rothkötter, Hermann-Josef

    2013-07-04

    The systemic effects of the Fusarium toxin deoxynivalenol (DON) and of bacterial lipopolysaccharides (LPS) were studied in male castrated pigs (40.4 ± 3.7 kg) infused intravenously with either DON or LPS alone (100 μg DON/kg/h, 7.5 μg/LPS/kg/h), or together (100 μg DON plus 7.5 μg/LPS/kg/h). The Control group received a saline infusion (n=6/treatment, 24h observation period). An additional DON infusion did not exacerbate the clinical signs observed in LPS-infused pigs. For example, rectal temperature climaxed after 4h (40.4 ± 0.2°C) and 5h (40.1 ± 0.3°C), in the LPS and LPS+DON group, respectively. Saline and DON alone did not induce an acute phase reaction as indicated by unaltered plasma levels of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) while LPS caused a significant rise of both cytokines. TNF-alpha plasma peak concentrations were significantly higher in the LPS compared to the DON+LPS group (94.3 ± 17.2 ng/mL vs. 79.2 ± 15.7 ng/mL) while IL-6 climaxed earlier in the latter group (3h p.i. vs. 2h p.i.). From the tested clinical-chemical plasma characteristics the total bilirubin concentration and the ASAT activity were strongly elevated by the LPS infusion and additionally increased and decreased by DON, respectively. In conclusion, the LPS-induced effects were only marginally modified by DON.

  20. Investigations of nuclear structure and nuclear reactions induced by complex projectiles. Progress report for the period September 1, 1992--August 31, 1993

    SciTech Connect

    Sarantites, D.G.

    1993-09-06

    This is a progress report on activities of the Washington University group in nuclear reaction studies for the period Sept 1, 1992 to Aug 31, 1993. This group has a research program which touches five areas of nuclear physics: nuclear structure studies at high spin; studies at the interface between structure and reactions; production and study of hot nuclei; reaction mechanism studies; development and use of novel techniques and instrumentation in the above areas of research. Specific activities of the group include in part: superdeformation in {sup 82}Sr; structure of and identical bands in {sup 182}Hg and {sup 178}Pt; a highly deformed band in {sup 136}Pm; particle decay of the {sup 164}Yb compound nucleus; fusion reactions; proton evaporation; two-proton decay of {sup 12}O; modeling and theoretical studies; excited {sup 16}O disassembly into four alpha particles; {sup 209}Bi + {sup 136}Xe collisions at 28.2 MeV/amu; and development work on 4{pi} solid angle gamma detectors, and x-ray detectors.

  1. Revised Calculations of the Production Rates for Co Isotopes in Meteorites Using New Cross Sections for Neutron-induced Reactions

    NASA Technical Reports Server (NTRS)

    Sisterson, J. M.; Brooks, F. D.; Buffler, A.; Allie, M. S.; Herbert, M. S.; Nchodu, M. R.; Makupula, S.; Ullmann, J.; Reedy, R. C.; Jones, D. T. L.

    2002-01-01

    New cross section measurements for reactions induced by neutrons with energies greater than 70 MeV are used to calculate the production rates for cobalt isotopes in meteorites and these new calculations are compared to previous estimates. Additional information is contained in the original extended abstract.

  2. Molecular cloning and characterization of two hypersensitive induced reaction genes from wheat infected by stripe rust pathogen

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A novel gene induced during hypersensitive reaction (HIR) in wheat was identified using in silico cloning and designated as TaHIR2. The TaHIR2 gene was deduced to encode a 284-amino acid protein, whose molecular mass and isoelectric point (pI) were 31.05 kD and 5.18, respectively. Amino acid sequenc...

  3. Investigation of Shock-Induced Chemical Reactions in Mo-Si Powder Mixtures Using Instrumented Experiments with PVDF Stress Gauges

    SciTech Connect

    Vandersall, K S; Thadhani, N N

    2001-05-29

    Shock-induced chemical reactions in {approx}58% dense Mo+2Si powder mixtures were investigated using time-resolved instrumented experiments, employing PVDF-piezoelectric stress gauges placed at the front and rear surfaces of the powders to measure the input and propagated stresses, and wave speed through the powder mixture. Experiments performed on the powders at input stresses less than 4 GPa, showed characteristics of powder densification and dispersed propagated wave stress profiles with rise time > {approx}40 nanoseconds. At input stress between 4-6 GPa, the powder mixtures showed a sharp rise time (<{approx}10 ns) of propagated wave profile and an expanded state of products revealing evidence of shock-induced chemical reaction. At input stresses greater than 6 GPa, the powder mixtures showed a slower propagated-stress-wave rise time and transition to a low-compressibility (melt) state indicating lack of shock-induced reaction. The results illustrate that premature melting of Si, at input stresses less than the crush-strength of the powder mixtures, restricts mixing between reactants and inhibits ''shock-induced'' reaction initiation.

  4. Extension of activation cross section data of deuteron induced nuclear reactions on rhodium up to 50 MeV

    NASA Astrophysics Data System (ADS)

    Hermanne, A.; Tárkányi, F.; Takács, S.; Ditrói, F.

    2015-11-01

    In the frame of the systematical study of light ion induced nuclear reactions activation cross sections for deuteron induced reactions on monoisotopic 103Rh were extended to 50 MeV incident energy. Excitation functions were measured in the 49.8-36.6 MeV energy range for the 103Rh(d,xn)100,101Pd, 103Rh(d,pxn)99m,99g,100,101m,101g,102m,102gRh and 103Rh(d,x)97,103Ru reactions by using the stacked foil irradiation technique and off-line high resolution γ-ray spectrometry. The experimental results are compared to our previous results and to the theoretical predictions in the TENDL-2014 library (TALYS 1.6 code).

  5. Extension of the Liège intranuclear-cascade model to reactions induced by light nuclei

    NASA Astrophysics Data System (ADS)

    Mancusi, Davide; Boudard, Alain; Cugnon, Joseph; David, Jean-Christophe; Kaitaniemi, Pekka; Leray, Sylvie

    2014-11-01

    The purpose of this paper is twofold. First, we present the extension of the Liège intranuclear-cascade model to reactions induced by light ions. We describe here the ideas upon which we built our treatment of nucleus-nucleus reactions and we compare the model predictions against a vast set of heterogeneous experimental data. In spite of the discussed limitations of the intranuclear-cascade scheme, we find that our model yields valid predictions for a number of observables and positions itself as one of the most attractive alternatives available to geant4 users for the simulation of light-ion-induced reactions. Second, we describe the c++ version of the code, which is physicswise equivalent to the legacy version, is available in geant4, and will serve as the basis for all future development of the model.

  6. Redox reactions induced by nitrosative stress mediate protein misfolding and mitochondrial dysfunction in neurodegenerative diseases.

    PubMed

    Gu, Zezong; Nakamura, Tomohiro; Lipton, Stuart A

    2010-06-01

    Overstimulation of N-methyl-D-aspartate (NMDA)-type glutamate receptors accounts, at least in part, for excitotoxic neuronal damage, potentially contributing to a wide range of acute and chronic neurologic diseases. Neurodegenerative disorders including Alzheimer's disease (AD) and Parkinson's disease (PD), manifest deposits of misfolded or aggregated proteins, and result from synaptic injury and neuronal death. Recent studies have suggested that nitrosative stress due to generation of excessive nitric oxide (NO) can mediate excitotoxicity in part by triggering protein misfolding and aggregation, and mitochondrial fragmentation in the absence of genetic predisposition. S-Nitrosylation, or covalent reaction of NO with specific protein thiol groups, represents a convergent signal pathway contributing to NO-induced protein misfolding and aggregation, compromised dynamics of mitochondrial fission-fusion process, thus leading to neurotoxicity. Here, we review the effect of S-nitrosylation on protein function under excitotoxic conditions, and present evidence suggesting that NO contributes to protein misfolding and aggregation via S-nitrosylating protein-disulfide isomerase or the E3 ubiquitin ligase parkin, and mitochondrial fragmentation through beta-amyloid-related S-nitrosylation of dynamin-related protein-1. Moreover, we also discuss that inhibition of excessive NMDA receptor activity by memantine, an uncompetitive/fast off-rate (UFO) drug can ameliorate excessive production of NO, protein misfolding and aggregation, mitochondrial fragmentation, and neurodegeneration.

  7. Measurement of neutron-induced reactions on 242mAm

    NASA Astrophysics Data System (ADS)

    Buckner, M. Q.; Wu, C.-Y.; Henderson, R. A.; Bucher, B.; Chyzh, A.; Bredeweg, T. A.; Baramsai, B.; Couture, A.; Jandel, M.; Mosby, S.; Ullmann, J. L.; Dance Collaboration

    2016-09-01

    Neutron-induced reaction cross sections of 242mAm were measured at the Los Alamos Neutron Science Center using the Detector for Advanced Neutron-Capture Experiments array along with a compact parallel-plate avalanche counter for fission-fragment detection. A new neutron-capture cross section was determined relative to a simultaneous measurement of the well-known 242mAm(n,f) cross section. The (n, γ) cross section was measured from thermal to an incident energy of 1 eV. Our new 242mAm fission cross section was normalized to ENDF/B-VII.1 and agreed well with the (n,f) cross section reported in the literature from thermal energy to 1 keV. The capture-to-fission ratio was determined from thermal energy to En = 0.1 eV, and it was found to be (n, γ)/(n,f) = 26(4)% compared to 19% from ENDF/B-VII.1. Our latest results will be reported. US Department of Energy by Lawrence Livermore National Security, LLC Contract DE-AC52-07NA27344 and Los Alamos National Security, LLC Contract DE-AC52-06NA25396 and U.S. DOE/NNSA Office of Defense Nuclear Nonproliferation Research and Development.

  8. Light-induced hetero-Diels-Alder cycloaddition: a facile and selective photoclick reaction.

    PubMed

    Arumugam, Selvanathan; Popik, Vladimir V

    2011-04-13

    2-Napthoquinone-3-methides (oNQMs) generated by efficient photodehydration (Φ=0.2) of 3-(hydroxymethyl)-2-naphthol undergo facile hetero-Diels-Alder addition (k(D-A)∼ 4×10(4) M(-1) s(-1)) to electron-rich polarized olefins in an aqueous solution. The resulting photostable benzo[g]chromans are produced in high to quantitative yield. The unreacted oNQM is rapidly hydrated (k(H2O) ∼145 s(-1)) to regenerate the starting diol. This competition between hydration and cycloaddition makes oNQMs highly selective, since only vinyl ethers and enamines are reactive enough to form the Diels-Alder adduct in an aqueous solution; no cycloaddition was observed with other types of alkenes. To achieve photolabeling or photoligation of two substrates, one is derivatized with a vinyl ether moiety, while 3-(hydroxymethyl)-2-naphthol is attached to the other via an appropriate linker. The light-induced Diels-Alder "click" strategy permits the formation of either a permanent or hydrolytically labile linkage. Rapid kinetics of this photoclick reaction (k=4×10(4) M(-1) s(-1)) is useful for time-resolved applications. The short lifetime (τ ∼7 ms in H(2)O) of the active form of the photoclick reagent prevents its migration from the site of irradiation, thus, allowing for spatial control of the ligation or labeling.

  9. Monoenergetic proton emission from nuclear reaction induced by high intensity laser-generated plasma.

    PubMed

    Torrisi, L; Cavallaro, S; Cutroneo, M; Giuffrida, L; Krasa, J; Margarone, D; Velyhan, A; Kravarik, J; Ullschmied, J; Wolowski, J; Szydlowski, A; Rosinski, M

    2012-02-01

    A 10(16) W∕cm(2) Asterix laser pulse intensity, 1315 nm at the fundamental frequency, 300 ps pulse duration, was employed at PALS laboratory of Prague, to irradiate thick and thin primary CD(2) targets placed inside a high vacuum chamber. The laser irradiation produces non-equilibrium plasma with deutons and carbon ions emission with energy of up to about 4 MeV per charge state, as measured by time-of-flight (TOF) techniques by using ion collectors and silicon carbide detectors. Accelerated deutons may induce high D-D cross section for fusion processes generating 3 MeV protons and 2.5 MeV neutrons, as measured by TOF analyses. In order to increase the mono-energetic proton yield, secondary CD(2) targets can be employed to be irradiated by the plasma-accelerated deutons. Experiments demonstrated that high intensity laser pulses can be employed to promote nuclear reactions from which characteristic ion streams may be developed. Results open new scenario for applications of laser-generated plasma to the fields of ion sources and ion accelerators.

  10. Immune reaction induced by X-rays and pions and its stimulation by schizophyllan (SPG).

    PubMed

    Inomata, T; Goodman, G B; Fryer, C J; Chaplin, D J; Palcic, B; Lam, G K; Nishioka, A; Ogawa, Y

    1996-07-01

    Female C57BL/6 mice aged 6-8 weeks with transplanted Lewis lung cancer cells were used to investigate the anti-tumour effects and immune reactions in tumour tissue induced by X-ray and pion irradiation and their modification by schizophyllan (SPG). The effect of SPG on the rate of lung metastasis and the survival time of the mice was also studied using the same tumour system. These studies showed that in this tumour system the "practical' relative biological effectiveness (RBE) of pions was 1.33 in the dose ranges used (3 Gy x 4 = P3; 6 Gy x 4 = P6). SPG increased the suppression of tumour growth associated with moderate doses of radiation: X-rays (4 Gy x 4 = X4) or P3. SPG also decreased the number of lung metastases and prolonged the life span of the mice, these effects being independent of radiation. The addition of SPG to radiation increased both the macrophage infiltration and T-lymphocyte infiltration in the local tumour and the lung nodules. There did not appear to be any major differential effect of SPG on the pion-treated mice compared with those treated with X-rays.

  11. Reaction-induced fracturing in a hot pressed calcite-periclase aggregate

    NASA Astrophysics Data System (ADS)

    Kuleci, H.; Ulven, O. I.; Rybacki, E.; Wunder, B.; Abart, R.

    2017-01-01

    The chemo-mechanical feedbacks associated with hydration of periclase immersed in a calcite matrix were investigated experimentally. Dense calcite-periclase aggregates with <5% porosity and with a calcite to periclase ratio of 90/10 and 95/5 by volume were prepared by hot isostatic pressing. Subsequent hydration experiments were performed in a hydrothermal apparatus at temperatures of 580-610 °C and a pressure of 200 MPa for run durations of 5-60 min. The rate of the periclase to brucite transformation was primarily controlled by the access of fluid. Where fluid was present, the reaction was too fast for the associated positive volume increase of the solids of about 100% to be accommodated by creep of the calcite matrix, and fracturing was induced. The newly formed cracks greatly enhanced the access of fluid leading to a positive feedback between hydration and fracturing. Mostly the newly formed cracks follow pre-existing grain boundaries in the calcite matrix. Comparison of experimental results with numerical 2D discrete element modelling (DEM) of crack formation revealed that the geometry of the crack pattern around a reacting particle depends on the shape of the original periclase particle, on the mechanical strength of the particle-matrix interface and on the mechanical strength and arrangement of grain boundaries in the calcite matrix in the immediate vicinity of the swelling particle.

  12. Letter: Observation of the 16O/18O exchange during electrospray ionization.

    PubMed

    Kostyukevich, Yury; Kononikhin, Alexey; Popov, Igor; Nikolaev, Eugene

    2015-01-01

    Isotopic exchange approach coupled to high-resolution mass spectrometry has become the power analytical approach for a wide range of analytical and bioanalyticall applications. Considerable efforts have been dedicated to developing fast exchange techniques directly in the ionization source. But all such methods are limited to the hydrogen/deuterium exchange approaches. In this paper we demonstrate that certain types of oxygen atoms can also be exchanged for (18)O on the time scale of the ionization process. Using HIO(3) and NaIO(4) and by infusing the heavy water H(2)(18)O in the ESI source we have demonstrated that it is possible to obtain a high level of oxygen exchange. It was observed that the rate of this exchange depends to a large extent on the temperature of the desolvating capillary of the mass spectrometer. Several other species, such as peptides, oligonucleotides and low weight organic molecules, were subjected to in-ESI (16)O/(18)O exchange but the exchange was not observed.

  13. Low excitations of 16O using generalized density matrix random phase approximation GDRPA

    NASA Astrophysics Data System (ADS)

    Taqi, Ali H.; Radhi, R. A.; Hussein, Adil M.

    2014-07-01

    The random phase approximation (RPA) equations based on the generalized density matrix (GDM), the so-called GDRPA are reformulated in a more compact matrix form, which renders the method especially suitable for realistic nuclear structure calculations. The GDRPA Hamiltonian is expressed in terms of the one-body particle-particle (pp) and hole-hole (hh) density matrices, and the nuclear force contributes not only in the particle-hole (ph) channel, as in normal ph-RPA, but also in the pp and hh channels. The Hamiltonian is diagonalized iteratively starting from initial guess values and the iterating process is carried out until self-consistency is achieved. The calculation in the model space 1p, 1d and 2s using Warburton and Brown interaction WBP is performed for 16O. The GDRPA in the ph shell model calculations is tested, by comparing the energy eigenvalues and the electron scattering form factors with the results of the normal RPA and with the available experimental data.

  14. α-particle elastic scattering from 12C, 16O, 24Mg, and 28Si

    NASA Astrophysics Data System (ADS)

    Behairy, Kassem O.; Mahmoud, Zakaria M. M.; Anwar, M.

    2017-01-01

    The elastic scattering of α-particle is analyzed in terms of the optical model over the energy 104-172.2 MeV for 12C, 48.7-146 MeV for 16O, 50-119 MeV for 24Mg, and 104, 166, 120 and 240 MeV for 28Si. We generate the real part of the optical model potential using the single folding model. In the single folding procedure, the ground state density of the target is folded with an effective density dependent α-nucleon interaction. For the imaginary part, the usual Woods-Saxon form is used. The parameters of the effective density dependent α-nucleon interaction are determined by fitting the experimental data of elastic scattering. The effective interaction's parameters are optimized using the χ2 criterion. We reasonably reproduce the elastic scattering cross sections for all studied systems. The obtained results reflect the success of our obtained α-nucleon effective interaction.

  15. Grape Marc Extract-Induced Defense Reactions and Protection against Phytophthora parasitica Are Impaired in NahG Tobacco Plants.

    PubMed

    Benouaret, Razik; Goupil, Pascale

    2015-08-05

    Grape marc extract (GME) acts as an elicitor of plant defense responses. This study analyzed GME-induced plant defense reactions in NahG transgenic tobacco. Leaf infiltration of NahG leaves revealed HR-like reactions with reduced lesions and weak deployment of autofluorescent compounds in the surrounding infiltrated tissues. The β-1,3-glucanase PR2-, endochitinase PR3-, and osmotin PR5-target transcript levels were strongly lowered in NahG leaves, and the mutant failed to accumulate the antimicrobial PR1 transcripts. GME-induced protection against Phytophthora parasitica var. nicotianae (Ppn) was evaluated on tobacco leaves. The antimicrobial properties of GME against Ppn were evidenced using a range of in vitro tests. GME-sprayed wild-type leaves showed reduced infection areas, whereas GME failed to induce a protective effect against Ppn in NahG leaves. The results suggest that GME-induced plant defense reactions in tobacco plants was mediated by salicylic acid (SA) and that GME-induced protection against Ppn could be the combined result of antimicrobial and defense actions.

  16. Determination of {sup 16}O and {sup 18}O sensitivity factors and charge-exchange processes in low-energy ion scattering

    SciTech Connect

    Tellez, H.; Chater, R. J.; Fearn, S.; Symianakis, E.; Kilner, J. A.; Brongersma, H. H.

    2012-10-08

    Quantitative analysis in low-energy ion scattering (LEIS) requires an understanding of the charge-exchange processes to estimate the elemental sensitivity factors. In this work, the neutralization of He{sup +} scattered by {sup 18}O-exchanged silica at energies between 0.6 and 7 keV was studied. The process is dominated by Auger neutralization for E{sub i} < 0.8 keV. An additional mechanism starts above the reionization threshold. This collision-induced neutralization becomes the dominant mechanism for E{sub i} > 2 keV. The ion fractions P{sup +} were determined for Si and O using the characteristic velocity method to quantify the surface density. The {sup 18}O/{sup 16}O sensitivity ratio indicates an 18% higher sensitivity for the heavier O isotope.

  17. Particle Generation by Pulsed Excimer Laser Ablation in Liquid: Hollow Structures and Laser-Induced Reactions

    NASA Astrophysics Data System (ADS)

    Yan, Zijie

    2011-12-01

    Pulsed laser ablation of solid targets in liquid media is a powerful method to fabricate micro-/nanoparticles, which has attracted much interest in the past decade. It represents a combinatorial library of constituents and interactions, and one can explore disparate regions of parameter space with outcomes that are impossible to envision a priori. In this work, a pulsed excimer laser (wavelength 248 nm, pulse width 30 ns) has been used to ablate targets in liquid media with varying laser fluences, frequencies, ablation times and surfactants. It is observed that hollow particles could be fabricated by excimer laser ablation of Al, Pt, Zn, Mg, Ag, Si, TiO2, and Nb2O5 in water or aqueous solutions. The hollow particles, with sizes from tens of nanometers to micrometers, may have smooth and continuous shells or have morphologies demonstrating that they were assembled from nanoparticles. A new mechanism has been proposed to explain the formation of these novel particle geometries. They were formed on laser-produced bubbles through bubble interface pinning by laser-produced solid species. Considering the bubble dynamics, thermodynamic and kinetic requirements have been discussed in the mechanism that can explain some phenomena associated with the formation of hollow particles, especially (1) larger particles are more likely to be hollow particles; (2) Mg and Al targets have stronger tendency to generate hollow particles; and (3) the 248 nm excimer laser is more beneficial to fabricate hollow particles in water than other lasers with longer wavelengths. The work has also demonstrated the possiblities to fabricate novel nanostructures through laser-induced reactions. Zn(OH)2/dodecyl sulfate flower-like nanostructures, AgCl cubes, and Ag2O cubes, pyramids, triangular plates, pentagonal rods and bars have been obtained via reactions between laser-produced species with water, electrolyes, or surfactant molecules. The underlying mechanisms of forming these structures have been

  18. Uraninite oxidation and dissolution induced by manganese oxide: A redox reaction between two insoluble minerals

    NASA Astrophysics Data System (ADS)

    Wang, Zimeng; Lee, Sung-Woo; Kapoor, Pratyul; Tebo, Bradley M.; Giammar, Daniel E.

    2013-01-01

    The longevity of subsurface U(IV) produced by reduction of U(VI) during in situ bioremediation can be limited by reoxidation to more mobile U(VI) species. Coupling of the biogeochemical cycles of U and Mn may affect the fate and transport of uranium. Manganese oxides can act as a powerful oxidant that accelerates the oxidative dissolution of UO2. This study investigated the physical and chemical factors controlling the interaction between UO2 and MnO2, which are both poorly soluble minerals. A multi-chamber reactor with a permeable membrane was used to eliminate direct contact of the two minerals while still allowing transport of aqueous species. The oxidation of UO2 was not significantly enhanced by MnO2 if the two solids were physically separated. Complete mixing of MnO2 with UO2 led to a much greater extent and rate of U oxidation. When direct contact is not possible, the reaction slowly progresses through release of soluble U(IV) with its adsorption and oxidation on MnO2. Continuously-stirred tank reactors (CSTRs) were used to quantify the steady-state rates of UO2 dissolution induced by MnO2. MnO2 dramatically promoted UO2 dissolution, but the degree of promotion leveled off once the MnO2:UO2 ratio exceeded a critical value. Substantial amounts of U(VI) and Mn(II) were retained on MnO2 surfaces. The total production of Mn(II) was less than that of U(VI), indicating that the fate of Mn products and their impact on UO2-MnO2 reaction kinetics were complicated and may involve formation of Mn(III) phases. At higher dissolved inorganic carbon concentrations, UO2 oxidation by MnO2 was faster and less U(VI) was adsorbed to MnO2. Such an inverse relationship suggested that U(VI) may passivate MnO2 surfaces. A conceptual model was developed to describe the oxidation rate of UO2 by MnO2. This model is potentially applicable to a broad range of water chemistry conditions and is relevant to other environmental redox processes involving two poorly soluble minerals.

  19. Endotoxin-induced coagulation reactions and phenoloxidase activity modulation in Sudanonautes africanus hemolymph fractions.

    PubMed

    Salawu, Musa Oyewole; Oloyede, Oyelola Bukoye

    2011-01-01

    Sudanonautes africanus is a freshwater crab local to Nigeria and West Africa that has no documentation of its innate immunity reactions. The objective of this study was to assess the effect of endotoxin (lipopolysaccharide [LPS]) on coagulation and on phenoloxidase (PO) activity in the hemolymph fractions of S. africanus. The hemolymph from each of 10 live crabs was obtained by carapace puncture and then fractionated into plasma and hemocytes. The hemocytes were then processed and then fractionated into hemocyte lysate (HL), hemocyte lysate supernatant (HLS), and hemocyte lysate debris (HLD). In one study, each fraction was then incubated with a fixed level of LPS in the presence or absence of exogenous calcium (Ca(2+)) ion. In another study, the LPS concentration was varied in order to study its effect on protein coagulation when an optimal ratio mixture of plasma:HLS was present as well as on PO activity in the plasma and HLS fractions. The results of the first set of studies demonstrated that a presence of Ca(2+) in the LPS-induced clotting reactions was essential. The next set of studies showed that a 7:1 plasma:HLS mixture yielded a higher level of coagulation than any other ratio tested in the presence of 1 EU LPS/ml. When this same plasma:HLS mixture ratio was used to ascertain the effect of varying LPS level on coagulation, the response trended higher up to a dose of 3.0 EU/ml., and decreased thereafter until 7 EU/ml. As expected based on the effect of LPS on PO activation, an increasing presence of LPS led to a general trend increase in activity of the enzyme in the plasma fraction; however, the effect was moreover inhibitory in the HLS fraction. From the results here, we conclude that protein coagulation is an important response, along with increased PO activity, that could manifest in Sudanonautes africanus after exposure to 'free' LPS or select LPS-bearing organisms in their environment.

  20. Radiation induced redox reactions and fragmentation of constituent ions in ionic liquids. 1. Anions.

    PubMed

    Shkrob, Ilya A; Marin, Timothy W; Chemerisov, Sergey D; Wishart, James F

    2011-04-14

    Room temperature ionic liquids (IL) find increasing use for the replacement of organic solvents in practical applications, including their use in solar cells and electrolytes for metal deposition, and as extraction solvents for the reprocessing of spent nuclear fuel. The radiation stability of ILs is an important concern for some of these applications, as previous studies suggested extensive fragmentation of the constituent ions upon irradiation. In the present study, electron paramagnetic resonance (EPR) spectroscopy has been used to identify fragmentation pathways for constituent anions in ammonium, phosphonium, and imidazolium ILs. Many of these detrimental reactions are initiated by radiation-induced redox processes involving these anions. Scission of the oxidized anions is the main fragmentation pathway for the majority of the practically important anions; (internal) proton transfer involving the aliphatic arms of these anions is a competing reaction. For perfluorinated anions, fluoride loss following dissociative electron attachment to the anion can be even more prominent than this oxidative fragmentation. Bond scission in the anion was also observed for NO(3)(-) and B(CN)(4)(-) anions and indirectly implicated for BF(4)(-) and PF(6)(-) anions. Among small anions, CF(3)SO(3)(-) and N(CN)(2)(-) are the most stable. Among larger anions, the derivatives of benzoate and imide anions were found to be relatively stable. This stability is due to suppression of the oxidative fragmentation. For benzoates, this is a consequence of the extensive sharing of unpaired electron density by the π-system in the corresponding neutral radical; for the imides, this stability could be the consequence of N-N σ(2)σ(*1) bond formation involving the parent anion. While fragmentation does not occur for these "exceptional" anions, H atom addition and electron attachment are prominent. Among the typically used constituent anions, aliphatic carboxylates were found to be the least

  1. Radiation induced redox reactions and fragmentation of constituent ions in ionic liquids. I. Anions.

    SciTech Connect

    Shkrob, I. A.; Marin, T.; Chemerisov, S.; Wishart, J.

    2011-04-14

    Room temperature ionic liquids (IL) find increasing use for the replacement of organic solvents in practical applications, including their use in solar cells and electrolytes for metal deposition, and as extraction solvents for the reprocessing of spent nuclear fuel. The radiation stability of ILs is an important concern for some of these applications, as previous studies suggested extensive fragmentation of the constituent ions upon irradiation. In the present study, electron paramagnetic resonance (EPR) spectroscopy has been used to identify fragmentation pathways for constituent anions in ammonium, phosphonium, and imidazolium ILs. Many of these detrimental reactions are initiated by radiation-induced redox processes involving these anions. Scission of the oxidized anions is the main fragmentation pathway for the majority of the practically important anions; (internal) proton transfer involving the aliphatic arms of these anions is a competing reaction. For perfluorinated anions, fluoride loss following dissociative electron attachment to the anion can be even more prominent than this oxidative fragmentation. Bond scission in the anion was also observed for NO{sub 3}{sup -} and B(CN){sub 4}{sup -} anions and indirectly implicated for BF{sub 4}{sup -} and PF{sub 6}{sup -} anions. Among small anions, CF{sub 3}SO{sub 3}{sup -} and N(CN){sub 2}{sup -} are the most stable. Among larger anions, the derivatives of benzoate and imide anions were found to be relatively stable. This stability is due to suppression of the oxidative fragmentation. For benzoates, this is a consequence of the extensive sharing of unpaired electron density by the {pi}-system in the corresponding neutral radical; for the imides, this stability could be the consequence of N-N {sigma}{sup 2}{sigma}*{sup 1} bond formation involving the parent anion. While fragmentation does not occur for these 'exceptional' anions, H atom addition and electron attachment are prominent. Among the typically used

  2. Empirical infrared line lists for five SO2 isotopologues: 32/33/34/36S16O2 and 32S18O2

    NASA Astrophysics Data System (ADS)

    Huang, Xinchuan; Schwenke, David W.; Lee, Timothy J.

    2015-05-01

    Using the latest published, empirically refined potential energy surface (PES) Ames-1 and purely ab initio CCSD(T)/aug-cc-pV(Q+d)Z dipole moment surface (DMS), we have computed infrared line lists for five symmetric isotopologues of sulfur dioxide: 32S16O2 (626), 33S16O2 (636), 34S16O2 (646), 36S16O2 (666), and 32S18O2 (828). The line lists are based on J = 0-80 rovibrational variational calculations with E‧ ⩽ 8000 cm-1. The 34S16O2 and 33S16O2 line lists are compared to the experiment-based models in the HIgh-resolution TRANsmission molecular absorption database (HITRAN2012,

  3. R-Matrix Evaluation of {sup 16}O neutron cross sections up to 6.3 MeV

    SciTech Connect

    Sayer, R.O.; Leal, L.C.; Larson, N.M.; Spencer, R.R.; and Wright, R.Q.

    2000-08-01

    In this paper the authors describe an evaluation of {sup 16}O neutron cross sections in the resolved resonance region with the multilevel Reich-Moore R-matrix formalism. Resonance analyses were performed with the computer code SAMMY [LA98] which utilizes Bayes' method, a generalized least squares technique.

  4. Isotopically uniform, 16O-depleted calcium, aluminum-rich inclusions in CH and CB carbonaceous chondrites

    NASA Astrophysics Data System (ADS)

    Krot, Alexander N.; Nagashima, Kazuhide; Petaev, Michail I.

    2012-04-01

    In situ oxygen-isotope measurements of calcium-aluminum-rich inclusions (CAIs) from the metal-rich carbonaceous chondrites Isheyevo (CH/CB-like), Acfer 214 paired with Acfer 182 (CH), QUE 94411 paired with QUE 94627 (CBb), and Hammadah al Hamra 237 (CBb) revealed the presence of a common population of igneous, isotopically uniform, 16O-depleted inclusions: Δ17O (average ± 2 standard deviations) = -7 ± 4‰, -6 ± 5‰, and -8 ± 3‰, respectively. All CAIs from CBs and a significant fraction of those from CHs and Isheyevo are 16O-depleted. Most of the 16O-depleted CAIs consist of Ti-poor Al-diopside, spinel, melilite, and forsterite and surrounded by a single- and double-layered rim of forsterite ± diopside. The 16O-depleted CAIs composed of hibonite, grossite, melilite, and spinel, and surrounded by the multilayered melilite + diopside ± forsterite rims are less common. Some of the 16O-depleted refractory igneous inclusions composed of Al-diopside, forsterite, and ±spinel have chondrule-like textures (skeletal or barred). They are mineralogically most similar to Al-diopside-rich chondrules found in metal-rich carbonaceous chondrites and composed of Al-diopside, forsterite, Al-rich low-Ca pyroxene, ±glassy mesostasis, and ±spinel, suggesting there is a continuum between these objects. We suggest that (i) most of the isotopically uniform and 16O-depleted CAIs resulted from remelting of pre-existing, possibly 16O-rich refractory inclusions. The remelting may have occurred during formation of the magnesian, non-porphyritic (cryptocrystalline and skeletal) chondrules in CHs, CBs, and Isheyevo either by an unspecified, late, single-stage, highly-energetic event or in an impact-generated plume previously hypothesized for their origin; both mechanisms probably occurred in the solar nebula (i.e., in the presence of the nebula gas). The forsterite ± pyroxene rims around 16O-depleted CAIs may have resulted from evaporation-recondensation of silicon and magnesium

  5. Effects of gas flow on oxidation reaction in liquid induced by He/O{sub 2} plasma-jet irradiation

    SciTech Connect

    Nakajima, Atsushi; Uchida, Giichiro Takenaka, Kosuke; Setsuhara, Yuichi; Kawasaki, Toshiyuki; Koga, Kazunori; Sarinont, Thapanut; Amano, Takaaki; Shiratani, Masaharu

    2015-07-28

    We present here analysis of oxidation reaction in liquid by a plasma-jet irradiation under various gas flow patterns such as laminar and turbulence flows. To estimate the total amount of oxidation reaction induced by reactive oxygen species (ROS) in liquid, we employ a KI-starch solution system, where the absorbance of the KI-starch solution near 600 nm behaves linear to the total amount of oxidation reaction in liquid. The laminar flow with higher gas velocity induces an increase in the ROS distribution area on the liquid surface, which results in a large amount of oxidation reaction in liquid. However, a much faster gas flow conversely results in a reduction in the total amount of oxidation reaction in liquid under the following two conditions: first condition is that the turbulence flow is triggered in a gas flow channel at a high Reynolds number of gas flow, which leads to a marked change of the spatial distribution of the ROS concentration in gas phase. Second condition is that the dimpled liquid surface is formed by strong gas flow, which prevents the ROS from being transported in radial direction along the liquid surface.

  6. Examining of athermal effects in microwave-induced glucose/glycine reaction and degradation of polysaccharide from Porphyra yezoensis.

    PubMed

    Zhou, Cunshan; Yu, Xiaojie; Ma, Haile; Liu, Shulan; Qin, Xiaopei; Yagoub, Abu El-Gasim A; Owusu, John

    2013-08-14

    Many reports claim the existence of athermal effects in microwave-induced reactions, and this challenge the assumption that the thermal effect (heating) is the sole factor in microwave heating. Therefore, microwave-induced Maillard reaction of d-glucose/glycine and degradation of polysaccharide from Porphyra yezoensis (PSPY) were investigated. Browning reactions were monitored by measuring heating rate, UV-absorbance and brown color, UV-vis and synchronous fluorescence spectra, GC/MS analysis and intrinsic viscosity of degradation. Heating of d-glucose/glycine solution produced brown compounds which were detected at A420, and the intermediate products, 2-acetylfuran and 5-methylfurfural, whose fluorescence intensity evidenced their formation. Maximum emission of synchronous fluorescence spectra of samples were at 430-440 nm and 370-390 nm. Both microwave and water bath heating did not cause any compositional changes in the Maillard reaction products. All data failed to show any significant athermal effects of compositional changes in the Maillard reaction products. It can be inferred that some of the reports suggesting the existence of athermal effects, which could ascribe to the different set-up obtained in not well temperature controlled microwave heating systems.

  7. A comparison between taste avoidance and conditioned disgust reactions induced by ethanol and lithium chloride in preweanling rats

    PubMed Central

    Arias, Carlos; Pautassi, Ricardo Marcos; Molina, Juan Carlos; Spear, Norman E.

    2011-01-01

    Adult rats display taste avoidance and disgust reactions when stimulated with gustatory stimuli previously paired with aversive agents such as lithium chloride (LiCl). By the second postnatal week of life, preweanling rats also display specific behaviors in response to a tastant conditioned stimulus (CS) that predicts LiCl-induced malaise. The present study compared conditioned disgust reactions induced by LiCl or ethanol (EtOH) in preweanling rats. In Experiment 1 we determined doses of ethanol and LiCl that exert similar levels of conditioned taste avoidance. After having equated drug dosage in terms of conditioned taste avoidance, 13-Day old rats were given a single pairing of a novel taste (saccharin) and either LiCl or ethanol (2.5 g/kg; Experiment 2). Saccharin intake and emission of disgust reactions were assessed 24 and 48 hours after training. Pups given paired presentations of saccharin and the aversive agents (ethanol or LiCl) consumed less saccharin during the first testing Day than controls. These pups also showed more aversive behavioral reactions to the gustatory CS than controls. Specifically, increased amounts of grooming, general activity, head shaking and wall climbing as well as reduced mouthing were observed in response to the CS. Conditioned aversive reactions but not taste avoidance were still evident on the second testing Day. In conclusion, a taste CS paired with post-absorptive effects of EtOH and LiCl elicited a similar pattern of conditioned rejection reactions in preweanling rats. These results suggest that similar mechanisms may be underlying CTAs induced by LiCl and a relatively high EtOH dose. PMID:20806327

  8. Neutron-induced reactions and secondary-ion mass spectrometry: complementary tools for depth profiling. Final report

    SciTech Connect

    Downing, G.; Fleming, R.; Simons, D.; Newbury, D.

    1982-01-01

    The technique of neutron depth profiling is based upon inducing nuclear reactions by bombardment with low-energy neutrons. The nuclear reactions result in the emission of high-energy alpha particles or protons. The energy spectrum of the emitted particles is used to derive a depth distribution by transforming the energy loss into an equivalent depth by stopping-power calculations. Depth profiles of bismuth distributions in silicon and tin have been measured by both neutron depth profiling and secondary ion mass spectrometry. Information from both techniques can be used synergistically to aid in a full characterization of the depth distribution.

  9. Reaction dynamics induced by the radioactive ion beam 7Be on medium-mass and heavy targets

    NASA Astrophysics Data System (ADS)

    Mazzocco, M.; Boiano, A.; Boiano, C.; La Commara, M.; Manea, C.; Parascandolo, C.; Pierroutsakou, D.; Stefanini, C.; Strano, E.; Torresi, D.; Acosta, L.; Di Meo, P.; Fernandez-Garcia, J. P.; Glodariu, T.; Grebosz, J.; Guglielmetti, A.; Keeley, N.; Lay, J. A.; Marquinez-Duran, G.; Martel, I.; Mazzocchi, C.; Molini, P.; Nicoletto, M.; Pakou, A.; Parkar, V. V.; Rusek, K.; Sánchez-Benítez, A. M.; Sandoli, M.; Sava, T.; Sgouros, O.; Signorini, C.; Silvestri, R.; Soramel, F.; Soukeras, V.; Stiliaris, E.; Stroe, L.; Toniolo, N.; Zerva, K.

    2015-10-01

    We studied the reaction dynamics induced at Coulomb barrier energies by the weakly-bound Radioactive Ion Beam 7Be (Sα = 1.586 MeV) on medium-mass (58Ni) and heavy (208Pb) targets. The experiments were performed at INFN-LNL (Italy), where a 2-3×105 pps 7Be secondary beam was produced with the RIB in-flight facility EXOTIC. Charged reaction products were detected by means of high-granularity silicon detectors in rather wide angular ranges. The contribution presents an up-to-date status of the data analysis and theoretical interpretation for both systems.

  10. Highly sensitive DNA detection using cascade amplification strategy based on hybridization chain reaction and enzyme-induced metallization.

    PubMed

    Yu, Xu; Zhang, Zhi-Ling; Zheng, Si-Yang

    2015-04-15

    A novel highly sensitive colorimetric assay for DNA detection using cascade amplification strategy based on hybridization chain reaction and enzyme-induced metallization was established. The DNA modified superparamagnetic beads were demonstrated to capture and enrich the target DNA in the hybridization buffer or human plasma. The hybridization chain reaction and enzyme-induced silver metallization on the gold nanoparticles were used as cascade signal amplification for the detection of target DNA. The metalization of silver on the gold nanoparticles induced a significant color change from red to yellow until black depending on the concentration of the target DNA, which could be recognized by naked eyes. This method showed a good specificity for the target DNA detection, with the capabilty to discriminate single-base-pair mismatched DNA mutation (single nucleotide polymorphism). Meanwhile, this approach exhibited an excellent anti-interference capability with the convenience of the magentic seperation and washing, which enabled its usage in complex biological systems such as human blood plasma. As an added benefit, the utilization of hybridization chain reaction and enzyme-induced metallization improved detection sensitivity down to 10pM, which is about 100-fold lower than that of traditional unamplified homogeneous assays.

  11. Acemannan-containing wound dressing gel reduces radiation-induced skin reactions in C3H mice

    SciTech Connect

    Roberts, D.B.; Travis, E.L.

    1995-07-15

    To determine (a) whether a wound dressing gel that contains acemannan extracted from aloe leaves affects the severity of radiation-induced acute skin reactions in C3H mice; (b) if so, whether other commercially available gels such as a personal lubricating jelly and a healing ointment have similar effects; and (c) when the wound dressing gel should be applied for maximum effect. Male C3H mice received graded single doses of gamma radiation ranging from 30 to 47.5 Gy to the right leg. In most experiments, the gel was applied daily beginning immediately after irradiation. Dose-response curves were obtained by plotting the percentage of mice that reached or exceeded a given peak skin reaction as a function of dose. Curves were fitted by logit analysis and ED{sub 50} values, and 95% confidence limits were obtained. The average peak skin reactions of the wound dressing gel-treated mice were lower than those of the untreated mice at all radiation doses tested. The ED{sub 50} values for skin reactions of 2.0-2.75 were approximately 7 Gy higher in the wound dressing gel-treated mice. The average peak skin reactions and the ED{sub 50} values for mice treated with personal lubricating jelly or healing ointment were similar to irradiated control values. Reduction in the percentage of mice with skin reactions of 2.5 or more was greatest in the groups that received wound dressing gel for at least 2 weeks beginning immediately after irradiation. There was no effect if gel was applied only before irradiation or beginning 1 week after irradiation. Wound dressing gel, but not personal lubricating jelly or healing ointment, reduces acute radiation-induced skin reactions in C3H mice if applied daily for at least 2 weeks beginning immediately after irradiation. 31 refs., 4 figs., 1 tab.

  12. Low-lying quasibound rovibrational states of H2 16O**

    NASA Astrophysics Data System (ADS)

    Szidarovszky, Tamás; Császár, Attila G.

    2013-08-01

    A complex coordinate scaling (CCS) method is described allowing the quantum chemical computation of quasibound (also called resonance or metastable) rovibrational states of strongly bound triatomic molecules. The molecule chosen to test the method is H2 16O, for which an accurate global potential energy surface, a previous computation of a few resonance states via the complex absorbing potential (CAP) method, and some Feshbach (J = 0, where J is the quantum number characterising overall rotations of the molecule) and shape (J ≠ 0) resonances measured via a state-selective, triple-resonance technique are all available. Characterisation of the computed resonance states is performed via probability density plots based on CCS rovibrational wavefunctions. Such plots provide useful details about the physical nature of the resonance states. Based on the computations and the resonance plots, the following useful facts about the resonance states investigated are obtained: (a) Feshbach resonances are formed by accumulation of a large amount of energy in either the non-dissociative bending or symmetric streching modes, excitations by more than five quanta are not uncommon; (b) there are several resonance states with low and medium bending excitation, the latter are different from the states observed somewhat below dissociation by the same triple-resonance technique; (c) several types of dissociation bahavior can be identified, varying greatly among the states; (d) several pairs of J = 0 and J = 1 Feshbach resonance states can be identified which differ by rigid-rotor type energies; and (e) the lifetimes of the assigned J = 1 rovibrational Feshbach resonances are considerably longer than the lifetimes of their J = 0 vibrational counterparts.

  13. Using 16O/18O to Determine the Evolutionary History of the R Coronae Borealis Stars

    NASA Astrophysics Data System (ADS)

    Clayton, Geoffrey; Geballe, Tom; Welch, Douglas; Tisserand, Patrick

    2014-08-01

    All of the Galactic hydrogen-deficient carbon (HdC) and R Coronae Borealis (RCB) stars for which oxygen isotopic ratios can be measured, show 16O/18O < 5, values that are orders of magnitude lower than measured in other stars (the Solar value is 500). This suggests that most if not all HdC and RCB stars are highly enriched in 18O. This is an important clue to determining the evolutionary pathways of HdC and RCB stars, for which two models have been proposed: the double degenerate (white dwarf (WD) merger), and the final helium-shell flash (FF). No overproduction of 18O is expected in the FF scenario. However, some RCB stars also show characteristics, such as 13C and Lithium, seen in FF stars. Therefore, we are conducting a survey of all the RCB stars in the LMC and SMC for the characteristics of a WD merger or a FF. Most of the stars have been surveyed for 13C already, and we are also planning to survey them for Lithium. But no RCB star in the Magellanic Clouds has been observed for 18O. The Magellanic Clouds provide an unbiased, relatively complete sample of RCB stars which are at a known distance so their bolometric luminosities can be used in our stellar evolution models. This proposal is to use Gemini/Flamingos-2 to survey all of the Magellanic Cloud stars, which are cool enough to show CO bands, for the presence of 18O near 2.3 micron. This survey, combined with our stellar evolution models, will reveal the true fraction of RCB stars formed by each of the proposed scenarios.

  14. Using 16O/18O to Determine the Evolutionary History of the R Coronae Borealis Stars

    NASA Astrophysics Data System (ADS)

    Clayton, Geoffrey; Geballe, Tom; Welch, Douglas; Tisserand, Patrick

    2013-08-01

    Of the Galactic hydrogen-deficient carbon (HdC) and R Coronae Borealis (RCB) stars for which oxygen isotopic ratios can be measured, all of them show 16O/18O < 5, values that are orders of magnitude lower than measured in other stars (the Solar value is 500). This suggests that most if not all HdC and RCB stars are highly enriched in 18O. This is an important clue in determining the evolutionary pathways of HdC and RCB stars, for which two models have been proposed: the double degenerate (white dwarf (WD) merger), and the final helium-shell flash (FF). No overproduction of 18O is expected in the FF scenario. However, some RCB stars also show characteristics, such as 13C and Lithium, seen in FF stars. Therefore, we are conducting a survey all the RCB stars in the LMC and SMC for the characteristics of a WD merger or a FF. Most of the stars have been surveyed for 13C already and we plan to survey them for Lithium in the future. This proposal is to use Gemini/Flamingos-2 to survey all the stars, which are cool enough to show CO bands, for the presence of 18O near 2.3 micron. The Magellanic Clouds provide an unbiased, relatively complete sample of RCB stars which are at a known distance so their bolometric luminosities can be used in our stellar evolution models. This survey, combined with our models, will reveal the true fraction of RCB stars formed by each of the proposed scenarios.

  15. α and 2p2n emission in fast neutron-induced reactions on Ni60

    DOE PAGES

    Fotiades, N.; Devlin, M.; Haight, R. C.; ...

    2015-06-19

    The cross sections for populating the residual nucleus in the reaction AZX(n,x)A-4Z-2Y exhibit peaks as a function of incident neutron energy corresponding to the (n,n'α) reaction and, at higher energy, to the (n,2p3n) reaction. In addition, the relative magnitudes of these peaks vary with the Z of the target nucleus.

  16. Theoretical cross section calculations of medical 13N and 18F radioisotope using alpha induced reaction

    NASA Astrophysics Data System (ADS)

    Kılınç, F.; Karpuz, N.; ćetin, B.

    2017-02-01

    In medical physics, radionuclides are needed to diagnose functional disorders of organs and to diagnose and treat many diseases. Nuclear reactions are significant for the productions of radionuclides. It is important to analyze the cross sections for much different energy. In this study, reactional cross sections calculations on 13N, 18F radioisotopes are with TALYS 1.6 nuclear reaction simulation code. Cross sections calculated and experimental data taken from EXFOR library were compared

  17. Air-Broadened Line Parameters for the 2←0 Bands of 13C16O and 12C18O at 2.3 μm

    NASA Astrophysics Data System (ADS)

    Devi, V. Malathy; Benner, D. Chris; Smith, M. A. H.; Mantz, A. W.; Sung, K.; Brown, L. R.

    2012-06-01

    Air-broadened line shape parameters were determined for the first time in the 2←0 bands of 13C16O near 4166.8 cm-1 and 12C18O near 4159.0 cm-1. Spectra were recorded at 0.005 cm-1 resolution using a coolable absorption cell in the sample compartment of the Bruker IFS 125HR Fourier transform spectrometer at Jet Propulsion Laboratory. Gas temperatures and pressures ranged from 150 to 298 K and 20 to 700 Torr, respectively. Line parameters were determined by broad-band multispectrum least-squares fitting of the 4000-4360 cm-1 region in 16 spectra simultaneously; each set included 4 isotope-enriched pure sample scans and 12 air+CO samples (13CO or C18O, as appropriate). The air-broadened parameters measured were Lorentz half-width coefficients, their temperature dependence exponents; pressure-induced shift coefficients, their temperature dependences; and off-diagonal relaxation matrix elements. Speed dependence parameters were included to minimize the fit residuals. For both isotopologues the individual line positions and intensities were constrained to their theoretical relationships in order to obtain the rovibrational (G, B, D, and H) and band intensity parameters, including Herman-Wallis coefficients. The results for 13C16O and 12C18O are compared with those for the 12C16O 2←0 band and discussed. K. Sung, A. W. Mantz, M. A. H. Smith, et al., JMS 262 (2010) 122-134. D. C. Benner, C. P. Rinsland, V. Malathy Devi, M. A. H. Smith and D. A. Atkins, JQSRT 53 (1995) 705-721. V. Malathy Devi, D. C. Benner, L. R. Brown, C. E. Miller and R. A. Toth, JMS 242 (2007) 90-117. V. Malathy Devi, D. C. Benner, M. A. H. Smith, et al., JQSRT (2012) in press. Research described in this paper was performed at Connecticut College, the College of William and Mary, NASA Langley Research Center and the Jet Propulsion Laboratory, California Institute of Technology, under contracts and cooperative agreements with the National Aeronautics and Space Administration.

  18. FT-IR spectra of 18O-, and 13C-enriched CO2 in the ν3 region: High accuracy frequency calibration and spectroscopic constants for 16O12C18O, 18O12C18O, and 16O13C16O

    NASA Astrophysics Data System (ADS)

    Elliott, Ben M.; Sung, Keeyoon; Miller, Charles E.

    2015-06-01

    In this report, we extend our Fourier transform infrared (FT-IR) spectroscopy measurements of CO2 in the ν3 region (2200-2450 cm-1, 65-75 THz) to the 18O-, and 13C-substituted isotopologues, using the JPL Bruker IFS-125HR Fourier Transform Spectrometer (JPL-FTS). High quality (S/N ∼ 2000) spectra were obtained separately for each of the 18O-, and 13C-isotopically enriched samples. The absolute wavenumber accuracies were better than 3 × 10-6 cm-1 (∼100 kHz) for strong, isolated transitions, calibrated against the highest accuracy reported CO and 16O12C16O (626) frequency measurements. The JPL-FTS performance and calibration procedure is shown to be reliable and consistent, achievable through vigorous maintenance of the optical alignment and regular monitoring of its instrumental line shape function. Effective spectroscopic constant fits of the 00011 ← 00001 fundamental bands for 16O12C18O (628), 18O12C18O (828), and 16O13C16O (636) were obtained with RMS residuals of 2.9 × 10-6 cm-1, 2.8 × 10-6 cm-1, and 2.9 × 10-6 cm-1, respectively. The observed bands encompassed 79 lines over the Jmax range of P67/R67, 47 lines over P70/R62, and 60 lines over P70/R70 for 628, 828, and 636, respectively. These results complement our recent work on the 17O-enriched isotopologues (Elliott et al., 2014), providing additional high-quality frequency measurements for atmospheric remote sensing applications.

  19. Identification of Maillard reaction induced chemical modifications on Ara h 1

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Maillard reaction is a non-enzymatic glycation reaction between proteins and reducing sugars that can modify nut allergens during thermal processing. These modifications can alter the structural and immunological properties of these allergens, and may result in increased IgE binding. Here, we ...

  20. Why a Proximity-Induced Diels–Alder Reaction is So Fast

    PubMed Central

    Krenske, Elizabeth H.; Perry, Emma W.; Jerome, Steven V.; Maimone, Thomas J.; Baran, Phil S.; Houk, K. N.

    2012-01-01

    Unlike normal Diels–Alder reactions of acyclic alkadienes with alkenes, the vinylbicyclo[2.2.2]octene employed in the Baran total synthesis of vinigrol undergoes quantitative Diels–Alder reaction with a tethered alkene at room temperature. Density functional theory calculations reveal that this unprecedented reactivity originates from a combination of preorganization, diene strain, and tether stabilization. PMID:22630569

  1. Low and medium energy deuteron-induced reactions on {sup 63,65}Cu nuclei

    SciTech Connect

    Simeckova, E.; Bem, P.; Honusek, M.; Stefanik, M.; Fischer, U.; Simakov, S. P.; Forrest, R. A.; Koning, A. J.; Sublet, J.-C.; Avrigeanu, M.; Roman, F. L.; Avrigeanu, V.

    2011-07-15

    The activation cross sections of (d,p), (d,2n), (d,3n), and (d,2p) reactions on {sup 63,65}Cu were measured in the energy range from 4 to 20 MeV using the stacked-foil technique. Then, following the available elastic-scattering data analysis that provided the optical potential for reaction cross-section calculations, an increased effort was devoted to the breakup mechanism, direct reaction stripping, and pre-equilibrium and compound-nucleus cross-section calculations, corrected for the breakup and stripping decrease of the total reaction cross section. The overall agreement between the measured and calculated deuteron activation cross sections proves the correctness of the nuclear mechanism account, next to the simultaneous analysis of the elastic-scattering and reaction data.

  2. Unusually high reactivity of apolipoprotein B-100 among proteins to radical reactions induced in human plasma.

    PubMed

    Hashimoto, R; Narita, S; Yamada, Y; Tanaka, K; Kojo, S

    2000-01-17

    Relative reactivities of proteins to radical reactions caused in human plasma were studied for the first time utilizing an immunoblotting assay. When radical reactions were caused by Cu(2+), apolipoprotein B-100 (apoB) underwent extensive fragmentation concurrently with the decrease in alpha-tocopherol, while human serum albumin (HSA) and transferrin (TF) were not decreased at all. When radical reactions were initiated by Cu(2+) with hydrogen peroxide or 2,2'-azobis(2-amidinopropane)dihydrochloride (AAPH), alpha-tocopherol and apoB were also decreased steadily but HSA and TF were not decreased. These observations indicate that apoB is extremely reactive, even comparable to alpha-tocopherol, towards radical reactions. These results also suggest that the radical reaction of apoB is a possible process in vivo and it is involved in atherogenesis along with low density lipoprotein lipid peroxidation, which has been studied extensively.

  3. A precise extraction of the induced polarization in the 4He(e,e'p)3H reaction

    SciTech Connect

    S.P. Malace, M. Paolone, S. Strauch

    2011-01-01

    We measured with unprecedented precision the induced polarization Py in 4He(e,e'p)3H at Q^2 = 0.8 (GeV/c)^2 and 1.3 (GeV/c)^2. The induced polarization is indicative of reaction-mechanism effects beyond the impulse approximation. Our results are in agreement with a relativistic distorted-wave impulse approximation calculation but are over-estimated by a calculation with strong charge-exchange effects. Our data are used to constrain the strength of the spin independent charge-exchange term in the latter calculation.

  4. Excitation Functions of Helion-Induced Nuclear Reactions for the Production of the Medical Radioisotope 103Pd

    NASA Astrophysics Data System (ADS)

    Skakun, Ye.; Qaim, S. M.

    2005-05-01

    Excitation functions were measured by the stacked-foil technique for the reactions 100Ru(α,n)103Pd, 101Ru(α,2n)103Pd, 101Ru(3He,n)103Pd, and 102Ru(3He,2n)103Pd for incident energies up to 25 and 34 MeV for α-particles and 3He ions, respectively. The integral thick target yields of the product radionuclide 103Pd calculated from the excitation functions of the above-named four reactions amount to 960, 1050, 50, and 725 KBq/μAh, respectively, at the maximum energy of the incident particle. The data are compared with the results of statistical model calculations and other charged particle induced reaction investigations.

  5. Study of activation cross-sections of deuteron induced reactions on rhodium up to 40 MeV

    NASA Astrophysics Data System (ADS)

    Ditrói, F.; Tárkányi, F.; Takács, S.; Hermanne, A.; Yamazaki, H.; Baba, M.; Mohammadi, A.; Ignatyuk, A. V.

    2011-09-01

    In the frame of a systematic study of the activation cross-sections of deuteron induced nuclear reactions, excitation functions of the 103Rh(d,x) 100,101,103Pd, 100g,101m,101g,102m,102gRh and 103gRu reactions were determined up to 40 MeV. Cross-sections were measured with the activation method using a stacked foil irradiation technique. Excitation functions of the contributing reactions were calculated using the ALICE-IPPE, EMPIRE-II and TALYS codes. From the measured cross-section data integral production yields were calculated and compared with experimental integral yield data reported in the literature. From the measured cross-sections and previous data, activation curves were deduced to support thin layer activation (TLA) on rhodium and Rh containing alloys.

  6. Photo-induced reactions of hemin (DMSO) n clusters (n = 0-3) produced with electrospray ionization

    NASA Astrophysics Data System (ADS)

    Nonose, S.; Tanaka, H.; Okai, N.; Shibakusa, T.; Fuke, K.

    2002-09-01

    Photo-induced reaction of [Fe(III)-protoporphyrin]^+ (hemin^+) ions solvated with dimethylsulfoxide (DMSO) is investigated by using a tandem mass spectrometer with electrospray ionization. We measure the photodissociation yields of mass-selected hemin^+(DMSO)n clusters for n = 0 3 in the energy region of 15 800 28 200 cm^{-1}. The mass spectra of the fragment ions show the β-cleavage of carboxymethyl groups in addition to the evaporation of solvent molecules. Yield of the β-cleavage reaction is found to depend strongly on the excitation energy and the number of solvent molecules. We also examine the metastable decomposition of the clusters following primary mass selection and determine the incremental solvent binding energies and internal energies for the clusters using evaporative ensemble model. From these results, we investigate the reaction mechanism of β-cleavage of hemin^+ ion.

  7. 2p1v states populated in 135Te from 9Be induced reactions with a 132Sn beam

    SciTech Connect

    Allmond, James M; Stuchbery, Andrew E; Brown, Alex; Beene, James R; Galindo-Uribarri, Alfredo {nmn}; Gross, Carl J; Liang, J Felix; Padilla-Rodal, Elizabeth; Radford, David C; Varner Jr, Robert L; Ayres, A.; Batchelder, J. C.; Bey, A.; Bingham, C. R.; Howard, Meredith E; Jones, K. L.; Manning, Brett M; Mueller, Paul Edward; Nesaraja, Caroline D; Pain, Steven D; Peters, William A; Ratkiewicz, Andrew J; Schmitt, Kyle; Shapira, Dan; Smith, Michael Scott; Stone, N. J.; Stracener, Daniel W; Yu, Chang-Hong

    2014-01-01

    Gamma-ray transitions in $^{134}$\\textrm{Te}, $^{135}$\\textrm{Te}, and $^{136}$\\textrm{Te} were measured from $^{9}$\\textrm{Be} induced reactions with a radioactive $^{132}$\\textrm{Sn} beam at a sub-Coulomb barrier energy of $3$~MeV per nucleon using particle-$\\gamma$ coincidence spectroscopy. The transitions were selected by gating on alpha-like particles in a \\textrm{CsI} detector following a combination of ($^{9}$\\textrm{Be},$\\alpha 1n$), ($^{9}$\\textrm{Be},$\\alpha 2n$), and ($^{9}$\\textrm{Be},$\\alpha 3n$) reactions. Distorted wave Born approximation calculations suggest little to no contribution from the ($^{9}$\\textrm{Be},$^{7}$\\textrm{He}), ($^{9}$\\textrm{Be},$^{6}$\\textrm{He}), and ($^{9}$\\textrm{Be},$^{5}$\\textrm{He}) direct reactions. Gamma-ray transitions from previously known $2^+\\otimes \

  8. CCN1 induces hepatic ductular reaction through integrin αvβ₅-mediated activation of NF-κB.

    PubMed

    Kim, Ki-Hyun; Chen, Chih-Chiun; Alpini, Gianfranco; Lau, Lester F

    2015-05-01

    Liver cholestatic diseases, which stem from diverse etiologies, result in liver toxicity and fibrosis and may progress to cirrhosis and liver failure. We show that CCN1 (also known as CYR61), a matricellular protein that dampens and resolves liver fibrosis, also mediates cholangiocyte proliferation and ductular reaction, which are repair responses to cholestatic injury. In cholangiocytes, CCN1 activated NF-κB through integrin αvβ5/αvβ3, leading to Jag1 expression, JAG1/NOTCH signaling, and cholangiocyte proliferation. CCN1 also induced Jag1 expression in hepatic stellate cells, whereupon they interacted with hepatic progenitor cells to promote their differentiation into cholangiocytes. Administration of CCN1 protein or soluble JAG1 induced cholangiocyte proliferation in mice, which was blocked by inhibitors of NF-κB or NOTCH signaling. Knock-in mice expressing a CCN1 mutant that is unable to bind αvβ5/αvβ3 were impaired in ductular reaction, leading to massive hepatic necrosis and mortality after bile duct ligation (BDL), whereas treatment of these mice with soluble JAG1 rescued ductular reaction and reduced hepatic necrosis and mortality. Blockade of integrin αvβ5/αvβ3, NF-κB, or NOTCH signaling in WT mice also resulted in defective ductular reaction after BDL. These findings demonstrate that CCN1 induces cholangiocyte proliferation and ductular reaction and identify CCN1/αvβ5/NF-κB/JAG1 as a critical axis for biliary injury repair.

  9. Measurement of the D/H, 18O/16O, and 17O/16O Isotope Ratios in Water by Laser Absorption Spectroscopy at 2.73 μm

    PubMed Central

    Wu, Tao; Chen, Weidong; Fertein, Eric; Masselin, Pascal; Gao, Xiaoming; Zhang, Weijun; Wang, Yingjian; Koeth, Johannes; Brückner, Daniela; He, Xingdao

    2014-01-01

    A compact isotope ratio laser spectrometry (IRLS) instrument was developed for simultaneous measurements of the D/H, 18O/16O and 17O/16O isotope ratios in water by laser absorption spectroscopy at 2.73 μm. Special attention is paid to the spectral data processing and implementation of a Kalman adaptive filtering to improve the measurement precision. Reduction of up to 3-fold in standard deviation in isotope ratio determination was obtained by the use of a Fourier filtering to remove undulation structure from spectrum baseline. Application of Kalman filtering enables isotope ratio measurement at 1 s time intervals with a precision (<1‰) better than that obtained by conventional 30 s averaging, while maintaining a fast system response. The implementation of the filter is described in detail and its effects on the accuracy and the precision of the isotope ratio measurements are investigated. PMID:24854363

  10. Visible light-induced photocatalytic reaction of gold-modified titanium(IV) oxide particles: action spectrum analysis.

    PubMed

    Kowalska, Ewa; Abe, Ryu; Ohtani, Bunsho

    2009-01-08

    Action spectrum analyses showed that visible light-induced oxidation of 2-propanol by aerated gold-modified titanium(IV) oxide (titania) suspensions is initiated by excitation of gold surface plasmon, and polychromatic irradiation experiments revealed that the photocatalytic reaction rate depends strongly on properties of titania, such as particle size, surface area and crystalline form (anatase or rutile) and on properties of gold deposits, such as size and shape.

  11. Estimating diffusivity along a reaction coordinate in the high friction limit: Insights on pulse times in laser-induced nucleation

    NASA Astrophysics Data System (ADS)

    Knott, Brandon C.; Duff, Nathan; Doherty, Michael F.; Peters, Baron

    2009-12-01

    In the high friction limit of Kramers' theory, the diffusion coefficient for motion along the reaction coordinate is a crucial parameter in determining reaction rates from mean first passage times. The Einstein relation between mean squared displacement, time, and diffusivity is inaccurate at short times because of ballistic motion and inaccurate at long times because trajectories drift away from maxima in the potential of mean force. Starting from the Smoluchowski equation for a downward parabolic barrier, we show how drift induced by the potential of mean force can be included in estimating the diffusivity. A modified relation between mean squared displacement, time, and diffusivity now also includes a dependence on the barrier curvature. The new relation provides the diffusivity at the top of the barrier from a linear regression that is analogous to the procedure commonly used with Einstein's relation. The new approach has particular advantages over previous approaches when evaluations of the reaction coordinate are costly or when the reaction coordinate cannot be differentiated to compute restraining forces or velocities. We use the new method to study the dynamics of barrier crossing in a Potts lattice gas model of nucleation from solution. Our analysis shows that some current hypotheses about laser-induced nucleation mechanisms lead to a nonzero threshold laser pulse duration below which a laser pulse will not affect nucleation. We therefore propose experiments that might be used to test these hypotheses.

  12. Hydroxyl radical induced by lipid in Maillard reaction model system promotes diet-derived N(ε)-carboxymethyllysine formation.

    PubMed

    Han, Lipeng; Li, Lin; Li, Bing; Zhao, Di; Li, Yuting; Xu, Zhenbo; Liu, Guoqin

    2013-10-01

    N(ε)-carboxymethyllysine (CML) is commonly found in food, and is considered as a potential hazard to human health. However, the effect of lipids on CML formation in Maillard reaction is still not clarified. In this study, the content of diet-derived CML and its key intermediates, epsilon-fructoselysine (FL) and glyoxal (GO), is determined with high performance liquid chromatography mass spectrum (HPLC-MS) in model system containing lipid compounds. According to the results, hydroxyl radical (OH) induced by Fenton reagent can promote the three pathways of CML formation. Moreover, in the Maillard reaction system, linoleic acid (Lin), oleic acid (Ole) and glycerol trioleate (Tri) can induce more OH·, which promotes CML formation. Their level of promoting CML formation is in the order of Ole>Lin>Tri. On the contrary, glycerol (Gly) can scavenge OH·, which inhibit the CML formation. Finally, it is proved that FL content and GO content decreases with heating time in model system, while CML content increases with heating time. Thus, it is concluded that in the Maillard reaction system lipids can induce more OH·, which promotes the conversion from FL and GO to CML. Our research may contribute to the development of inhibitory methods for diet-derived CML by scavenging OH·.

  13. Dynamics of surface-migration: Electron-induced reaction of 1,2-dihaloethanes on Si(100)

    NASA Astrophysics Data System (ADS)

    Huang, Kai; MacLean, Oliver; Guo, Si Yue; McNab, Iain R.; Ning, Zhanyu; Wang, Chen-Guang; Ji, Wei; Polanyi, John C.

    2016-10-01

    Scanning Tunneling Microscopy was used to investigate the electron-induced reaction of 1,2-dibromoethane (DBE) and 1,2-dichloroethane (DCE) on Si(100).We observed a long-lived physisorbed molecular state of DBE at 75 K and of DCE at 110 K. As a result we were able to characterize by experiment and also by ab initio theory the dynamics of ethylene production in the electron-induced surface-reaction of these physisorbed species. For both DBE and DCE the ethylene product was observed to migrate across the surface. In the case of DBE the recoil of the ethylene favored the silicon rows, migrating by an average distance of 22 Å, and up to 100 Å. Trajectory calculations were performed for this electron-induced reaction, using an 'Impulsive Two-State' model involving an anionic excited state and a neutral ground-potential. The model agreed with experiment in reproducing both migration and desorption of the ethylene product. The computed migration exhibited a 'ballistic' launch and subsequent 'bounces', thereby accounting for the observed long-range migratory dynamics.

  14. Experimental and Computational Induced Aerodynamics from Missile Jet Reaction Controls at Angles of Attack to 75 Degrees

    NASA Technical Reports Server (NTRS)

    Capone, Francis J.; Ashbury, Scott C.; Deere, Karen A.

    1996-01-01

    An investigation was conducted in the Langley 16-Foot Transonic Tunnel to determine induced aerodynamic effects from jet reaction controls of an advanced air-to-air missile concept. The 75-percent scale model featured independently controlled reaction jets located near the nose and tail of the model. Aerodynamic control was provided by four fins located near the tail of the model. This investigation was conducted at Mach numbers of 0.35 and 0.60, at angles of attack up to 75 deg and at nozzle pressure ratios up to 90. Jet-reaction thrust forces were not measured by the force balance but jet-induced forces were. In addition, a multiblock three-dimensional Navier-Stokes method was used to calculate the flowfield of the missile at angles of attack up to 40 deg. Results indicate that large interference effects on pitching moment were induced from operating the nose jets with the the off. Excellent correlation between experimental and computational pressure distributions and pitching moment were obtained a a Mach number of 0.35 and at angles of attack up to 40 deg.

  15. Quantum confinement effect of CdSe induced by nanoscale solvothermal reaction.

    PubMed

    Lee, Jin-Wook; Im, Jeong-Hyuk; Park, Nam-Gyu

    2012-10-21

    We report a novel method, nanoscale solvothermal reaction (NSR), to induce the quantum confinement effect of CdSe on nanostructured TiO(2) by solvothermal route. The time-dependent growth of CdSe is observed in solution at room temperature, which is found to be accomplished instantly by heat-treatment in the presence of solvent at 1 atm. However, no crystal growth occurs upon heat-treatment in the absence of solvent. The nanoscale solvothermal growth of CdSe quantum dot is realized on the nanocrystalline oxide surface, where Cd(NO(3))(2)·4H(2)O and Na(2)SeSO(3) solutions are sequentially spun on nanostructured TiO(2), followed by heat-treatment at temperatures ranging from 100 °C to 250 °C. Size of CdSe increases from 4.4 nm to 5.3 nm, 8.7 nm and 14.8 nm, which results in decrease in optical band gap from 2.19 eV to, 1.95 eV, 1.74 eV and 1.75 eV with increasing the NSR temperature from 100 °C to 150 °C, 200 °C and 250 °C, respectively, which is indicative of the quantum confinement effect. Thermodynamic studies reveal that increase in the size of CdSe is related to increase in enthalpy, for instance, from 3.77 J mg(-1) for 100 °C to 8.66 J mg(-1) for 200 °C. Quantum confinement effect is further confirmed from the CdSe-sensitized solar cell, where onset wavelength in external quantum efficiency spectra is progressively shifted from 600 nm to 800 nm as the NSR temperature increases, which leads to a significant improvement of power conversion efficiency by a factor of more than four. A high photocurrent density of 13.7 mA cm(-2) is obtained based on CdSe quantum dot grown by NSR at 200 °C.

  16. Statistical Hauser-Feshbach theory with width-fluctuation correction including direct reaction channels for neutron-induced reactions at low energies

    NASA Astrophysics Data System (ADS)

    Kawano, T.; Capote, R.; Hilaire, S.; Chau Huu-Tai, P.

    2016-07-01

    A model to calculate particle-induced reaction cross sections with statistical Hauser-Feshbach theory including direct reactions is given. The energy average of the scattering matrix from the coupled-channels optical model is diagonalized by the transformation proposed by Engelbrecht and Weidenmüller [C. A. Engelbrecht and H. A. Weidenmüller, Phys. Rev. C 8, 859 (1973), 10.1103/PhysRevC.8.859]. The ensemble average of S -matrix elements in the diagonalized channel space is approximated by a model of Moldauer [P. A. Moldauer, Phys. Rev. C 12, 744 (1975), 10.1103/PhysRevC.12.744] using the newly parametrized channel degree-of-freedom νa to better describe the Gaussian orthogonal ensemble (GOE) reference calculations. The Moldauer approximation is confirmed by a Monte Carlo study using a randomly generated S matrix, as well as the GOE threefold integration formula. The method proposed is applied to the 238U(n ,n' ) cross-section calculation in the fast-energy range, showing an enhancement in the inelastic scattering cross sections.

  17. Solvent-Induced Reversal of Activities between Two Closely Related Heterogeneous Catalysts in the Aldol Reaction

    SciTech Connect

    Kandel, Kapil; Althaus, Stacey M; Peeraphatdit, Chorthip; Kobayashi, Takeshi; Trewyn, Brian G; Pruski, Marek; Slowing, Igor I

    2013-01-11

    The relative rates of the aldol reaction catalyzed by supported primary and secondary amines can be inverted by 2 orders of magnitude, depending on the use of hexane or water as a solvent. Our analyses suggest that this dramatic shift in the catalytic behavior of the supported amines does not involve differences in reaction mechanism, but is caused by activation of imine to enamine equilibria and stabilization of iminium species. The effects of solvent polarity and acidity were found to be important to the performance of the catalytic reaction. This study highlights the critical role of solvent in multicomponent heterogeneous catalytic processes.

  18. - and Air-Broadening of 12C16O, 13C16O and 12C18O at 2.3 μm

    NASA Astrophysics Data System (ADS)

    Devi, V. Malathy; Benner, D. Chris; Smith, Mary Ann H.; Mantz, Arlan W.; Sung, Keeyoon; Brown, Linda R.

    2011-06-01

    High resolution (0.005 Cm-1) absorption spectra of CO and two of its isotopologues (13CO and C18O) were recorded between 3550 and 5250 Cm-1 using the Bruker IFS-125HR Fourier transform spectrometer (FTS) located at the Jet Propulsion Laboratory (JPL) and a specially designed and built coolable 20.38 cm long absorption cell placed within the sample compartment of the FTS. More than 50 spectra of both pure and air-broadened samples of CO, 13CO and C18O were recorded at various temperatures from 150 K to 298 K, with maximum total pressures up to ˜700 Torr. A multispectrum nonlinear least squares spectrum fitting technique was used to determine the spectral line shape parameters including speed dependence, Lorentz halfwidth coefficients, pressure-induced shift coefficients, and off-diagonal relaxation matrix element coefficients for line mixing. These line shape parameters were obtained for both self- and air-broadening, and temperature dependences of these parameters were determined where possible. As previously done in studies of CO_2, rather than retrieving individual line positions and intensities, we constrained them to their theoretical relationships, including Herman-Wallis terms, determining only the band intensities and rovibrational constants. The results are discussed and compared with values reported in the literature. K. Sung, A. W. Mantz, M. A. H. Smith, L. R. Brown, T. J. Crawford, V. Malathy Devi and D. C. Benner, JMS 262 (2010) 122-134. D. C. Benner, C. P. Rinsland, V. Malathy Devi, M. A. H. Smith and D. A. Atkins, JQSRT 53 (1995) 705-721. V. Malathy Devi, D. C. Benner, L. R. Brown, C. E. Miller and R. A. Toth, JMS 242 (2007) 90-117. Research described in this paper was performed at Connecticut College, the College of William and Mary, NASA Langley Research Center and the Jet Propulsion Laboratory, California Institute of Technology, under contracts and cooperative agreements with the National Aeronautics and Space Administration.

  19. Proteomics of ionomycin-induced ascidian sperm reaction: Released and exposed sperm proteins in the ascidian Ciona intestinalis.

    PubMed

    Nakazawa, Shiori; Shirae-Kurabayashi, Maki; Otsuka, Kei; Sawada, Hitoshi

    2015-12-01

    Sperm proteins mediating sperm-egg interaction should be exhibited on the sperm surface, or exposed or released when sperm approach an egg. In ascidians (protochordates), sperm undergo a sperm reaction, characterized by enhanced sperm motility and mitochondrial swelling and shedding on contact with the vitelline coat (VC) or by treatment with Ca(2+) ionophore. Here, proteomic analysis was conducted on sperm exudates and sperm surface proteins using ionomycin-induced sperm reaction and cell-impermeable labeling in Ciona intestinalis type A (C. robusta). In the exudate from sperm treated with ionomycin, membrane proteins including a possible VC receptor CiUrabin were abundant, indicating the release of membranous compartments during sperm reaction. Among the surface proteins XP_009859314.1 (uncharacterized protein exhibiting homology to HrTTSP-1) was most abundant before the sperm reaction, but XP_004227079.1 (unknown Ig superfamily protein) appears to be most abundantly exposed by the sperm reaction. Moreover, proteins containing a notable set of domains, astacin-like metalloprotease domain and thrombospondin type 1 repeat(s), were found in this fraction. Possible roles in fertilization as well as localizations and behaviors of these proteins are discussed.

  20. Improved Data Set for the Herzberg Band Systems of 16O 2

    NASA Astrophysics Data System (ADS)

    Mérienne, Marie-France; Jenouvrier, Alain; Coquart, Bernard; Carleer, Michel; Fally, Sophie; Colin, Reginald; Vandaele, A. C.; Hermans, Christian

    2001-05-01

    Total number of files: 3+README.TXT Filenames: O2_HERZB.TXT NON_ATT.TXT O2_PARAM.TXT Filetypes: ASCII I-O2_HERZB.TXT The assignments and intensities in the 41261-34000 cm-1 region include the data from ref.1 and 2, and additional data from revisited spectra (ref.3). 1-FOURIER TRANSFORM SPECTROSCOPY OF THE O2 HERZBERG BANDS I. ROTATIONAl ANALYSIS A. Jenouvrier, M-F. Merienne, B. Coquart, M. Carleer, S. Fally, A.C. Vandaele, C. Hermans and R. Colin Journal of Molecular Spectroscopy 198,136-162 (1999) 2-FOURIER TRANSFORM SPECTROSCOPY OF THE O2 HERZBERG BANDS II. BAND OSCILLATOR STRENGTHS AND TRANSITION MOMENTS M-F. Merienne, A. Jenouvrier, B. Coquart, M. Carleer, S. Fally, R. Colin, A.C. Vandaele and C. Hermans Journal of Molecular Spectroscopy 202, 171-193 (2000) 3-IMPROVED DATA SET FOR THE HERZBERG BAND SYSTEMS OF {16}O2 M-F. Merienne, A. Jenouvrier, B. Coquart, M. Carleer, S. Fally, R. Colin, A.C. Vandaele and C. Hermans Journal of Molecular Spectroscopy DESCRIPTION: Columns: 1-Wavenumber in cm-1. 'c' denotes a calculated value for a blended line. 2-Integrated line cross section in 10-26 cm2 cm-1 molecule-1. '*' denotes a saturated line for which the value has been calculated. 3-Assignment in the order : electronic transition, vibrational band v'-0, branch, rotational assignment (N"). For the overlapped lines, the value in [ ] is the estimated integrated cross section. II-NON_ATT.TXT Lines which cannot be identified as {16}O2 transitions. DESCRIPTION: Columns: 1-Wavenumber in cm-1. 2-Integrated line cross section in 10-26 cm2 cm-1 molecule-1. III-O2_PARAM.TXT This file contains tables for the molecular parameters and the transition moments. table 1: A(3)Sigma(u)+ parameters (in cm-1): the numbers in parentheses are two standard deviations (2sigma) in units of the last digits. DESCRIPTION: Columns: 1-Vibrational quantum number v. 2-Band origin T(v) referred to the hypothetical X(3)Sigma(g)-, F2, N = J = 0 level. 3-Rotational constant B(v). 4-Rotational centrifugal

  1. Proton exchange in acid-base complexes induced by reaction coordinates with heavy atom motions

    NASA Astrophysics Data System (ADS)

    Alavi, Saman; Taghikhani, Mahdi

    2012-06-01

    We extend previous work on nitric acid-ammonia and nitric acid-alkylamine complexes to illustrate that proton exchange reaction coordinates involve the rocking motion of the base moiety in many double hydrogen-bonded gas phase strong acid-strong base complexes. The complexes studied involve the biologically and atmospherically relevant glycine, formic, acetic, propionic, and sulfuric acids with ammonia/alkylamine bases. In these complexes, the magnitude of the imaginary frequencies associated with the proton exchange transition states are <400 cm-1. This contrasts with widely studied proton exchange reactions between symmetric carboxylic acid dimers or asymmetric DNA base pair and their analogs where the reaction coordinate is localized in proton motions and the magnitude of the imaginary frequencies for the transition states are >1100 cm-1. Calculations on complexes of these acids with water are performed for comparison. Variations of normal vibration modes along the reaction coordinate in the complexes are described.

  2. Disassembly of hot nuclear matter formed in Au-induced reactions near the Fermi energy

    SciTech Connect

    Delis, D.N.

    1993-09-01

    Complex fragment emission has been studied in the 60 MeV/A {sup 197}Au + {sup 12}C, {sup 27}Al, {sup 51}V, {sup nat}Cu, and {sup 197}Au reactions. Velocity spectra, angular distributions and cross sections have been constructed for each target from the inclusive data. Coincidence data including 2-, 3-, 4-, and 5-fold events have also been examined. Furthermore neutron multiplicity distributions have been obtained for the above reactions by utilizing a novel neutron calorimetric approach.

  3. Investigations of nuclear structure and nuclear reactions induced by complex projectiles

    SciTech Connect

    Sarantites, D.G.

    1991-01-01

    The research program of our group touches five areas of nuclear physics: (1) Nuclear structure studies at high spin; (2) Studies at the interface between structure and reactions; (3) Production and study of hot nuclei; (4) Incomplete fusion and fragmentation reactions; and (5) Development and use of novel techniques and instrumentation in the above areas of research. The papers from these areas are discussed in this report.

  4. Concurrent Application of ANC and THM to assess the 13C(α, n)16O Absolute Cross Section at Astrophysical Energies and Possible Consequences for Neutron Production in Low-mass AGB Stars

    NASA Astrophysics Data System (ADS)

    Trippella, O.; La Cognata, M.

    2017-03-01

    The {}13{{C}}{(α ,n)}16{{O}} reaction is considered to be the main neutron source responsible for the production of heavy nuclides (from {Sr} to {Bi}) through slow n-capture nucleosynthesis (s-process) at low temperatures during the asymptotic giant branch phase of low-mass stars (≲ 3{--}4 {M}ȯ , or LMSs). In recent years, several direct and indirect measurements have been carried out to determine the cross section at the energies of astrophysical interest (around 190+/- 40 {keV}). However, they yield inconsistent results that cause a highly uncertain reaction rate and affect the neutron release in LMSs. In this work we have combined two indirect approaches, the asymptotic normalization coefficient and the Trojan horse method, to unambiguously determine the absolute value of the {}13{{C}}{(α ,n)}16{{O}} astrophysical factor. With these, we have determined a very accurate reaction rate to be introduced into astrophysical models of s-process nucleosynthesis in LMSs. Calculations using this recommended rate have shown limited variations in the production of those neutron-rich nuclei (with 86≤slant A≤slant 209) that receive contribution only by slow neutron captures.

  5. Inducible costimulatory molecule deficiency induced imbalance of Treg and Th17/Th2 delays rejection reaction in mice undergoing allogeneic tracheal transplantation

    PubMed Central

    Xu, Jingsong; Wu, Yu; Wang, Guifang; Qin, Yanghua; Zhu, Li; Tang, Gusheng; Shen, Qian

    2014-01-01

    Objective: This study aimed to investigate the role of inducible costimulatory molecule (ICOS) pathway in the rejection reaction of mice undergoing allogeneic tracheal transplantation. Methods: The bronchus was separated from wide-type (WT) BalB/c mice and transplanted into WT BalB/c mice, C57 mice and icos-/- mice to prepare the obliterative bronchiolitis (OB) animal model. The transplanted bronchus was pathologically examined; flow cytometry was done to detect the T cell subsets and activity of the bronchus and spleen of recipient mice. Results: 21 d after transplantation, evident rejection reaction was observed and the proportion of Th2 and Th17 cells increased significantly in the bronchus and spleen in C57 mice receiving allogeneic tracheal transplantation when compared with mice with autologous transplantation, but the proportion of Treg cells was comparable between them. When compared with WT BalB/c mice, the proportion of Th2, Th17 and Treg cells reduced markedly and rejection reaction was attenuated in icos-/- mice receiving tracheal transplantation, although rejection reaction was still noted. Conclusion: icos knockout may delay the rejection reaction after tracheal transplantation, which might be ascribed to the imbalance among Th2, Th17 and Treg cells. PMID:25628788

  6. Nonthermal nuclear reactions induced by fast α particles in the solar core

    NASA Astrophysics Data System (ADS)

    Voronchev, Victor T.

    2015-02-01

    Nonthermal nuclear effects triggered in the solar carbon-nitrogen-oxygen (CNO) cycle by fast α particles—products of the p p chain reactions—are examined. The main attention is paid to 8.674-MeV α particles generated in the 7Li(p ,α ) α reaction. Nonthermal characteristics of these α particles and their influence on some nuclear processes are determined. It is found that the α -particle effective temperature is at a level of 1.1 MeV and exceeds the solar core temperature by 3 orders of magnitude. These fast particles are able to significantly enhance some endoergic (α ,p ) reactions neglected in standard solar model calculations. In particular, they can substantially affect the balance of the p +17O⇄α +14N reactions due to an appreciable increase of the reverse reaction rate. It is shown that in the region R =0.08 -0.25 R⊙ the reverse α +14N reaction can block the forward p +17O reaction, thus preventing closing of the CNO-II cycle, and increase the 17O abundance by a factor of 2-155 depending on R . This indicates that the fast α particles produced in the p p cycle can distort running of the CNO cycle, making it essentially different in the inner and outer core regions.

  7. Interplay of projectile breakup and target excitation in reactions induced by weakly bound nuclei

    NASA Astrophysics Data System (ADS)

    Gómez-Ramos, M.; Moro, A. M.

    2017-03-01

    Background: Reactions involving weakly bound nuclei require formalisms able to deal with continuum states. The majority of these formalisms struggle to treat collective excitations of the systems involved. For continuum-discretized coupled channels (CDCC), extensions to include target excitation have been developed but have only been applied to a small number of cases. Purpose: In this work, we reexamine the extension of the CDCC formalism to include target excitation and apply it to a variety of reactions to study the effect of breakup on inelastic cross sections. Methods: We use a transformed oscillator basis to discretize the continuum of the projectiles in the different reactions and use the extended CDCC method developed in this work to solve the resulting coupled differential equations. A new code has been developed to perform the calculations. Results: Reactions 58Ni(d ,d )*58Ni , 24Mg(d ,d )*24Mg , 144Sm(6Li,6Li)*144Sm , and 9Be(6Li,6Li)*9Be are studied. Satisfactory agreement is found between experimental data and extended CDCC calculations. Conclusions: The studied CDCC method has proven to be an accurate tool to describe target excitation in reactions with weakly bound nuclei. Moderate effects of breakup on inelastic observables are found for the reactions studied. Cross-section magnitudes are not modified much, but angular distributions present smoothing when opposed to calculations without breakup.

  8. Interplay of the elastic and inelastic channels in the 16O+27Al scattering at Elab = 280 MeV

    NASA Astrophysics Data System (ADS)

    Cappuzzello, F.; Nicolosi, D.; Linares, R.; Oliveira, J. R. B.; Lubian, J.; Agodi, C.; Carbone, D.; Cavallaro, M.; de Faria, P. N.; Foti, A.; Rodrigues, M. R. D.

    2016-06-01

    Recent data indicated a nuclear rainbow-like pattern in the elastic scattering of 16O + 27Al at E_{lab}=100 MeV that arises from couplings of the ground to the low-lying states of the 27Al nucleus. Similar effect was identified in the elastic angular distribution of 16O + 12C at E_{lab}=281 and 330 MeV. These experiments show a crucial role of microscopic details of nuclear structure in the elastic scattering of heavy ions at energies well above the Coulomb barrier. In this work we investigate the 16O + 27Al system at E_{lab}=280 MeV for which a coupled channel calculation predicts a pronounced nuclear rainbow-like structure. Obtained experimental data show evidences of an important coupling of the elastic channel to the inelastic. Coupled channel calculations reproduce the experimental angular distributions when a re-normalization factor on the real part of the optical potential is introduced. A proper theoretical approach still requires a high degree of accuracy for the nuclear structure models and new tools to deal with collective excitations.

  9. Proteomic analysis of cellular response induced by boron neutron capture reaction in human squamous cell carcinoma SAS cells.

    PubMed

    Sato, Akira; Itoh, Tasuku; Imamichi, Shoji; Kikuhara, Sota; Fujimori, Hiroaki; Hirai, Takahisa; Saito, Soichiro; Sakurai, Yoshinori; Tanaka, Hiroki; Nakamura, Hiroyuki; Suzuki, Minoru; Murakami, Yasufumi; Baiseitov, Diaz; Berikkhanova, Kulzhan; Zhumadilov, Zhaxybay; Imahori, Yoshio; Itami, Jun; Ono, Koji; Masunaga, Shinichiro; Masutani, Mitsuko

    2015-12-01

    To understand the mechanism of cell death induced by boron neutron capture reaction (BNCR), we performed proteome analyses of human squamous tumor SAS cells after BNCR. Cells were irradiated with thermal neutron beam at KUR after incubation under boronophenylalanine (BPA)(+) and BPA(-) conditions. BNCR mainly induced typical apoptosis in SAS cells 24h post-irradiation. Proteomic analysis in SAS cells suggested that proteins functioning in endoplasmic reticulum, DNA repair, and RNA processing showed dynamic changes at early phase after BNCR and could be involved in the regulation of cellular response to BNCR. We found that the BNCR induces fragments of endoplasmic reticulum-localized lymphoid-restricted protein (LRMP). The fragmentation of LRMP was also observed in the rat tumor graft model 20 hours after BNCT treatment carried out at the National Nuclear Center of the Republic of Kazakhstan. These data suggest that dynamic changes of LRMP could be involved during cellular response to BNCR.

  10. The hypersensitive induced reaction and leucine-rich repeat proteins regulate plant cell death associated with disease and plant immunity.

    PubMed

    Choi, Hyong Woo; Kim, Young Jin; Hwang, Byung Kook

    2011-01-01

    Pathogen-induced programmed cell death (PCD) is intimately linked with disease resistance and susceptibility. However, the molecular components regulating PCD, including hypersensitive and susceptible cell death, are largely unknown in plants. In this study, we show that pathogen-induced Capsicum annuum hypersensitive induced reaction 1 (CaHIR1) and leucine-rich repeat 1 (CaLRR1) function as distinct plant PCD regulators in pepper plants during Xanthomonas campestris pv. vesicatoria infection. Confocal microscopy and protein gel blot analyses revealed that CaLRR1 and CaHIR1 localize to the extracellular matrix and plasma membrane (PM), respectively. Bimolecular fluorescent complementation and coimmunoprecipitation assays showed that the extracellular CaLRR1 specifically binds to the PM-located CaHIR1 in pepper leaves. Overexpression of CaHIR1 triggered pathogen-independent cell death in pepper and Nicotiana benthamiana plants but not in yeast cells. Virus-induced gene silencing (VIGS) of CaLRR1 and CaHIR1 distinctly strengthened and compromised hypersensitive and susceptible cell death in pepper plants, respectively. Endogenous salicylic acid levels and pathogenesis-related gene transcripts were elevated in CaHIR1-silenced plants. VIGS of NbLRR1 and NbHIR1, the N. benthamiana orthologs of CaLRR1 and CaHIR1, regulated Bax- and avrPto-/Pto-induced PCD. Taken together, these results suggest that leucine-rich repeat and hypersensitive induced reaction proteins may act as cell-death regulators associated with plant immunity and disease.

  11. Blue bottle light: lecture demonstrations of homogeneous and heterogeneous photo-induced electron transfer reactions.

    PubMed

    Mills, Andrew; Lawrie, Katherine; McFarlane, Michael

    2009-03-01

    The classic, non-photochemical blue bottle experiment involves the reaction of methylene blue (MB) with deprotonated glucose, to form a bleached form of the dye, leuco-methylene blue (LMB), and subsequent colour recovery by shaking with air. This reaction is a popular demonstrator of key principles in kinetics and reaction mechanisms. Here it is modified so as to highlight features of homogenous and heterogeneous photoinduced electron transfer (PET) (Pure Appl. Chem., 2007, 79, 293-465) reactions, i.e.blue bottle light experiments. The homogeneous blue bottle light experiment uses methylene blue, MB, as the photo-sensitizer and triethanolamine as the sacrificial electron donor. Visible light irradiation of this system leads to its rapid bleaching, followed by the ready restoration of its original colour upon shaking away from the light source. The heterogeneous blue bottle light experiment uses titania as the photo-sensitizer, MB as a redox indicator and glucose as the sacrificial electron donor. UVA light irradiation of this system leads to the rapid bleaching of the MB and the gradual restoration of its original colour with shaking and standing. The latter 'dark' step can be made facile and more demonstrator-friendly by using platinised titania particles. These two photochemical versions of the blue bottle experiment are used to explore the factors which underpin homogeneous and heterogeneous PET reactions and provide useful demonstrations of homogeneous and heterogeneous photochemistry.

  12. Thermodynamic forward modeling of retrogressive hydration reactions induced by geofluid infiltration

    NASA Astrophysics Data System (ADS)

    Kuwatani, Tatsu; Toriumi, Mitsuhiro

    2017-01-01

    We have developed a new methodology for forward analysis of retrogressive hydration (rehydration) reactions by an improved thermodynamic forward modeling technique based on a differential thermodynamic approach (Gibbs' method). Based on natural observations and theoretical considerations, the progress of a rehydration reaction is modeled by incorporating a change in the effective bulk composition on account of the breakdown of the non-equilibrated phase and the amount of water infiltration into the system. Forward analyses of rehydration reactions under greenschist-facies conditions show that (1) the reaction progress of rehydration is proportional to the external water supply, and (2) the mineral compositions of equilibrated minerals are mainly controlled by P- T conditions and are similar to those in the global equilibrium model. Calculated results are in accordance with natural observations of rehydration reactions in greenschist-facies rocks, which supports the validity of the proposed model. The proposed model can be used as a basic forward model for various inversion analyses and numerical simulations and thus to understand the distribution and behavior of geofluids.[Figure not available: see fulltext.

  13. Isomeric yield ratios and excitation functions in α-induced reactions on 107,109Ag

    NASA Astrophysics Data System (ADS)

    Guin, R.; Saha, S. K.; Prakash, Satya; Uhl, M.

    1992-07-01

    Isomeric yield ratios for the reactions 107Ag(α,3n)108In, 107Ag(α,α3n)104Ag, 109Ag(α,2n)111In, and 109Ag(α,3n)110In are determined in the energy range of 20-63 MeV α particles. Excitation functions for the above reactions as well as for the 107Ag(α,2n)109In, 107Ag(α,α2n)105Ag, 109Ag(α,4n)109In, 109Ag(α,5n)108In, and 109Ag(α,α4n)105Ag reactions are also presented. Experimental excitation functions are compared with statistical model calculations taking into account precompound particle emission. Isomeric yield ratios are found to depend strongly on the root mean square orbital angular momentum in the entrance channel. A semiempirical method for the prediction of isomeric yield ratios failed to reproduce experimental data even for compoundlike reactions. Isomeric yield ratios were also calculated in the frame of a statistical model under consideration of angular momentum effects in the preequilibrium and the equilibrium stage. Overall agreement between the theory and the experiment for isomeric yield ratios was found to be satisfactory especially at low bombarding energy when compound nucleus reaction channel is dominant. The discrepancy observed at higher bombarding energies needs to be theoretically investigated in greater detail.

  14. Cross sections, momentum distributions, and neutron angular distributions for 11Be induced reactions on silicon

    NASA Astrophysics Data System (ADS)

    Negoita, F.; Borcea, C.; Carstoiu, F.; Lewitowicz, M.; Saint-Laurent, M. G.; Anne, R.; Guillemaud-Mueller, D.; Mueller, A. C.; Pougheon, F.; Sorlin, O.; Fomitchev, A.; Lukyanov, S.; Penionzhkevich, Yu.; Skobelev, N.; Dlouhy, Z.

    1999-04-01

    The halo neutron breakup cross section for 11Be on Si has been obtained in a wide energy range by applying an integral method and separately determining the contributions of stripping and dissociation mechanisms. A new breakup mechanism, for which the core energy is strongly dumped, has also been observed. Parallel momentum distributions of 10Be resulting from breakup have been deduced for both stripping and dissociation and angular and energy distributions of the neutrons coincident with different reaction products have been measured. Charge changing cross sections for 10,11Be complemented the measurements. An extended Glauber model has been elaborated in order to provide a unitary interpretation for all the data. It takes into account both the specific structure of 11Be and the reaction mechanism, practically without free parameters. The effects of reaction mechanisms on the widths of observed momentum distributions are particularly important.

  15. Neutron Induced Reactions with the 17 Mev Facility at the Athens Tandem Accelerator NCSR 'Demokritos'

    NASA Astrophysics Data System (ADS)

    Vlastou, R.; Kalamara, A.; Serris, M.; Diakaki, M.; Kokkoris, M.; Paneta, V.; Axiotis, M.; Lagoyannis, A.

    In the 5.5 MV tandem T11/25 Accelerator Laboratory of NCSR "Demokritos" monoenergetic neutron beams have been produced in the energy range∼ 15-20 MeV using anew Ti-tritiated target of 373 GBq activity, by means of the 3H(d,n)4He reaction. The corresponding deuteron beam energies obtained from the accelerator, were in the 1.5-4.5MeV range.The maximum flux has been determined to be of the order of 106 n/cm2 s, implementing reference reactions. The 17.1MeV neutron beam has been used for the measurement of 197Au(n,2n) reaction cross section. Theoretical calculations have been performed via the statistical model code EMPIRE and compared to the experimental data of the present work and data from literature.

  16. Activation cross sections for reactions induced by 14 MeV neutrons on natural tantalum

    SciTech Connect

    Luo Junhua; Tuo Fei; Kong Xiangzhong

    2009-05-15

    Cross sections for (n,2n), (n,p), (n,n{sup '}{alpha}), (n,t), (n,d{sup '}), and (n,{alpha}) reactions have been measured on tantalum isotopes at the neutron energies of 13.5 to 14.7 MeV using the activation technique. Data are reported for the following reactions: {sup 181}Ta(n,2n){sup 180}Ta{sup g}, {sup 181}Ta(n,p){sup 181}Hf, {sup 181}Ta(n,n{sup '}{alpha}){sup 177}Lu{sup m}, {sup 181}Ta(n,t){sup 179}Hf{sup m2}, {sup 181}Ta(n,d{sup '}){sup 180}Hf{sup m}, and {sup 181}Ta(n,{alpha}){sup 178}Lu{sup m}. The neutron fluences were determined using the monitor reaction {sup 27}Al(n,{alpha}){sup 24}Na. Results were discussed and compared with the previous works.

  17. Formation of indoor nitrous acid (HONO) by light-induced NO2 heterogeneous reactions with white wall paint.

    PubMed

    Bartolomei, Vincent; Sörgel, Matthias; Gligorovski, Sasho; Alvarez, Elena Gómez; Gandolfo, Adrien; Strekowski, Rafal; Quivet, Etienne; Held, Andreas; Zetzsch, Cornelius; Wortham, Henri

    2014-01-01

    Gaseous nitrogen dioxide (NO2) represents an oxidant that is present in relatively high concentrations in various indoor settings. Remarkably increased NO2 levels up to 1.5 ppm are associated with homes using gas stoves. The heterogeneous reactions of NO2 with adsorbed water on surfaces lead to the generation of nitrous acid (HONO). Here, we present a HONO source induced by heterogeneous reactions of NO2 with selected indoor paint surfaces in the presence of light (300 nm<λ<400 nm). We demonstrate that the formation of HONO is much more pronounced at elevated relative humidity. In the presence of light (5.5 W m(-2)), an increase of HONO production rate of up to 8.6·10(9) molecules cm(-2) s(-1) was observed at [NO2]=60 ppb and 50% relative humidity (RH). At higher light intensity of 10.6 (W m(-2)), the HONO production rate increased to 2.1·10(10) molecules cm(-2) s(-1). A high NO2 to HONO conversion yield of up to 84% was observed. This result strongly suggests that a light-driven process of indoor HONO production is operational. This work highlights the potential of paint surfaces to generate HONO within indoor environments by light-induced NO2 heterogeneous reactions.

  18. Deuteron Induced ( d,p) and ( d,2p) Nuclear Reactions up to 50 MeV

    NASA Astrophysics Data System (ADS)

    Yiğit, M.; Tel, E.; Kara, A.

    2013-06-01

    Many studies have shown that the nuclear reactions of charged particles with nuclei are very important in many fields of nuclear physics. The interactions of deuterons with nuclei have been especially the subject of common research in the history of nuclear physics. Moreover, the knowledge of cross section for deuteron-nucleus interactions are required for various application such as space applications, accelerator driven sub-critical systems, nuclear medicine, nuclear fission reactors and controlled thermonuclear fusion reactors. Particularly, the future of controlled thermonuclear fusion reactors is largely dependent on the nuclear reaction cross section data and the selection of structural fusion materials. Finally, the reaction cross section data of deuteron induced reactions on fusion structural materials are of great importance for development and design of both experimental and commercial fusion devices. In this work, reaction model calculations of the cross sections of deuteron induced reactions on structural fusion materials such as Al ( Aluminium), Ti ( Titanium), Cu ( Copper), Ni ( Nickel), Co ( Cobalt), Fe ( Iron), Zr ( Zirconium), Hf ( Hafnium) and Ta ( Tantalum) have been investigated. The new calculations on the excitation functions of 27 Al( d,2p) 27 Mg, 47 Ti( d,2p) 47 Sc, 65 Cu( d,2p) 65 Ni, 58 Ni( d,2p) 58 Co, 59 Co( d,2p) 59 Fe, 58 Fe( d,p) 59 Fe, 96 Zr( d,p) 97 Zr, 180 Hf ( d,p) 181 Hf and 181 Ta( d,p) 182 Ta have been carried out for incident deuteron energies up to 50 MeV. In these calculations, the equilibrium and pre-equilibrium effects for ( d,p) and ( d,2p) reactions have been investigated. The equilibrium effects are calculated according to the Weisskopf-Ewing ( WE) Model. The pre-equilibrium calculations involve the new evaluated the Geometry Dependent Hybrid Model ( GDH) and Hybrid Model. In the calculations the program code ALICE/ASH was used. The calculated results are discussed and compared with the experimental data taken from the

  19. Future prospects of nuclear reactions induced by gamma-ray beams at ELI-NP

    NASA Astrophysics Data System (ADS)

    Filipescu, D.; Balabanski, D. L.; Camera, F.; Gheorghe, I.; Ghita, D.; Glodariu, T.; Kaur, J.; Ur, C. A.; Utsunomiya, H.; Varlamov, V. V.

    2017-01-01

    The future prospects of photonuclear reactions studies at the new Extreme Light Infrastructure—Nuclear Physics (ELI-NP) facility are discussed in view of the pursuit of investigating the electromagnetic response of nuclei using γ-ray beams of unprecedented energy resolution and intensity characteristics. We present here the features of the γ-ray beam source, the emerging ELI-NP experimental program involving photonuclear reactions cross section measurements and spectroscopy and angular measurements of γ-rays and neutrons along with the detection arrays currently under implementation.

  20. Alpha-induced reaction studies using low-energy RI beams at CRIB

    SciTech Connect

    Yamaguchi, H.; Kahl, D.; Hu, J.; Kubono, S.; Hayakawa, S.; Hashimoto, T.

    2012-11-12

    CRIB (CNS Radioactive Ion Beam separator) is a low-energy RI beam separator at the Center for Nuclear Study (CNS) of the University of Tokyo. Studies on proton and alpha resonance scatterings, ({alpha}, p) reactions, and other types of measurements ({beta}-decay lifetimes etc.) have been performed using RI beams at CRIB, motivated by interests on astrophysical reactions and exotic nuclear structure. Among the studies at CRIB, the measurement of {sup 7}Li+{alpha}/{sup 7}Be+{alpha} resonant scatterings are presented.

  1. Multinucleon mechanisms in (γ,N) and (γ,NN) reactions

    NASA Astrophysics Data System (ADS)

    Ryckebusch, Jan; Machenil, Lars; Vanderhaeghen, Marc; van der Sluys, Veerle; Waroquier, Michel

    1994-05-01

    The similarities in the experimental indications for multinucleon mechanisms in (γ,p) and (e,e'p) processes are pointed out. For both types of reactions, the substantial role of two-nucleon emission processes for transitions to high excitation energies in the residual nucleus is stressed. A microscopic model for the calculation of the two-body knockout contributions to the inclusive (γ,N) reaction is presented. It is based on an unfactorized formalism for the calculation of electromagnetically induced two-nucleon emission cross sections. The model is shown to yield a reasonable description of the overall behavior of the 12C(γ,p) and 12C(γ,n) data at high excitation energies in the residual nucleus. In the calculations, effects from nonresonant and resonant pion exchange currents are included. Photoabsorption on these currents is predicted to produce the major contributions to the exclusive 16O(γ,n0)15O process at photoenergies above the pion threshold. Double differential cross sections for photon induced pp and pn emission from 16O are calculated and compared with the data.

  2. New excitation functions for proton induced reactions on natural titanium, nickel and copper up to 70 MeV

    NASA Astrophysics Data System (ADS)

    Garrido, E.; Duchemin, C.; Guertin, A.; Haddad, F.; Michel, N.; Métivier, V.

    2016-09-01

    New excitation functions for proton induced nuclear reactions on natural titanium, nickel and copper were measured, using the stacked-foil technique and gamma spectrometry, up to 70 MeV. The experimental cross sections were measured using the Ti-nat(p,x) V-48, Ni-nat(p,x) Ni-57 and Cu-nat(p,x) Zn-62,Co-56 monitor reactions recommended by the International Atomic Energy Agency (IAEA), depending on the investigated energy range. Data have been extracted for the Ti-nat(p,x) Sc-43,44m,46,47,48, V-48, K-42,43, Ni-nat(p,x) Ni-56,57, Co-55,56,57,58, Mn-52,54, Cu-nat(p,x) Cu-61,64, Ni-57, Co-56,57,58,60, Zn-62,65, Mn-54 reactions. Our results are discussed and compared to the existing ones as well as with the TALYS code version 1.6 calculations using default models. Our experimental data are in overall good agreement with the literature. TALYS is able to reproduce, in most cases, the experimental trend. Our new experimental results allow to expand our knowledge on these excitation functions, to confirm the existing trends and to give additional values on a large energy range. This work is in line with the new Coordinated Research Project (CRP) launched by the IAEA to expand the database of monitor reactions.

  3. Hydrogen peroxide induces premature acrosome reaction in rat sperm and reduces their penetration of the zona pellucida.

    PubMed

    Hsu, P C; Hsu, C C; Guo, Y L

    1999-11-29

    Recent studies have demonstrated that mammalian sperm are capable of generating reactive oxygen species (ROS) and that this activity is significantly accelerated in subfertile subjects. The observed decrease in penetration of zona-intact oocyte might be explained by chemical-induced ROS-related early onset of capacitation and premature acrosome reaction, but the mechanism is not clear. We determine whether zona-intact oocyte penetration capability in rat epididymal sperm was affected by premature acrosome reaction in rat sperm treated with hydrogen peroxide (H2O2) and calcium ionophore A23187 or H2O2 and lysophosphatidyl choline. Chlortetracycline fluorescence assay was used to study the status of acrosome reaction on epididymal sperm. The sperm-oocyte binding and penetration assay was used to evaluate the capability for zona pellucida penetration. There was a positive linear correlation between the frequency of acrosome-reacted sperm and capability of sperm-oocyte binding and penetration in zona-free oocytes. In the zona-intact oocytes, the sperm-oocyte penetration rate was suppressed as the proportions of acrosome-reacted sperm increased. In summary, this study showed that premature acrosome reaction reduced rat sperm's capability of penetrating zona-intact oocytes. However, this reduction is not seen in zona-free oocytes. These findings may provide a basis for understanding the effects of sperm ROS generation on zona pellucida penetration in male reproductive toxicology.

  4. Rare Red Rashes: A Case Report of Levetiracetam-Induced Cutaneous Reaction and Review of the Literature.

    PubMed

    Jones, Ryan T; Evans, William; Mersfelder, Tracey L; Kavanaugh, Kevin

    2016-01-01

    Cutaneous reactions secondary to medications are rare but can be serious events resulting in morbidity and mortality and can be caused by anticonvulsant medications. Levetiracetam has been considered relatively safe compared with other antiepileptics with regard to skin eruptions. We report a case of a cutaneous reaction secondary to levetiracetam. A 64-year-old man presented to the hospital with an altered mental status and aphasia. Imaging revealed a left basal ganglia mass. A biopsy of the lesion was obtained, and levetiracetam was started at 500 mg intravenously twice a day for seizure prophylaxis. After 13 doses, the patient developed a diffuse, erythematous, warm, blanching, morbilliform rash. Levetiracetam was discontinued, and methylprednisolone was started. After 4 days, the rash dissipated. Levetiracetam is an antiepileptic medication that has an unknown mechanism of action. To date, there are only 4 cases reported involving skin reactions from levetiracetam. Two of the cases were classified as Stevens-Johnson Syndrome: 1 as toxic epidermal necrolysis and 1 as erythema multiforme. Our case was classified as a morbilliform rash. A Naranjo score of 7 suggested a probable cause for a levetiracetam-induced skin reaction. Antiepileptic medications are used in certain cases to prevent seizures in patients with central nervous system tumors. Although levetiracetam seems to have fewer side effects than the traditional antiepileptic medications, it is important for the healthcare provider to continuously evaluate the need for all medications and discontinue unneeded ones to help avoid potential medication adverse effects.

  5. Participation of protein kinases and phosphatases in the progesterone-induced acrosome reaction and calcium influx in human spermatozoa.

    PubMed

    Barón, L; Fara, K; Zapata-Carmona, H; Zuñiga, L; Kong, M; Signorelli, J; Díaz, E S; Morales, P

    2016-11-01

    In human spermatozoa, protein kinases have a role in the acrosome reaction (AR) induced by a variety of stimuli. However, there is disagreement or a lack of information regarding the role of protein kinases and phosphatases in the progesterone (P)-induced increase in intracellular calcium concentration ([Ca(2+) ]i ). In addition, there are no studies regarding the role of Ser/Thr and Tyr phosphatases and there are contradictory results regarding the role of Tyr kinases in the P-induced acrosome reaction. Here, we performed a simultaneous evaluation of the involvement of protein kinases and phosphatases in the P-induced acrosome reaction and in the P-induced calcium influx. Motile spermatozoa were capacitated for 18 h and different aliquots were allocated to treated or control groups and then evaluated for their ability to undergo the acrosome reaction and to increase [Ca(2+) ]i in response to P. The acrosome reaction was evaluated using Pisum sativum agglutinin (PSA)-FITC, and [Ca(2+) ]i was evaluated using fura 2AM. At all of the concentrations tested, PKA inhibitors significantly reduced the percentage of the P-induced acrosome reaction (p < 0.001). However, only the highest concentrations of PKA inhibitors reduced the P-induced calcium influx; lower concentrations of PKA inhibitors did not affect it. Similar results were apparent for PKC inhibitors and for tyrosine kinase inhibitors. None of the Ser/Thr phosphatase inhibitors affected the P-induced acrosome reaction or the P-induced calcium influx, except for the PP2B inhibitors that significantly reduced the P-induced acrosome reaction without affecting calcium influx. Finally, the protein tyrosine phosphatase inhibitors significantly blocked the P-induced acrosome reaction and reduced the amplitude of the P-induced calcium transient (p < 0.001) as well as the amplitude of the plateau phase (p < 0.01). The data suggest that protein kinases and possibly PP2B have a role on the acrosome reaction at some

  6. Drug Reaction with Eosinophilia and Systemic Symptom (DRESS) induced by carbamazepine: a case report and literature review

    PubMed Central

    EL Omairi, Nissrine; Abourazzak, Sanae; Chaouki, Sanae; Atmani, Samir; Hida, Moustapha

    2014-01-01

    Drug-induced hypersensitivity or Drug Reaction with Eosinophilia and Systemic Symptom (DRESS) is a severe adverse drug-induced reaction. Diagnosing DRESS is challenging due to the diversity of cutaneous eruption and organs involved. Most of the aromatic anticonvulsants, such as phenytoin, phenobarbital, and carbamazepine, can induce DRESS. Culprit drug withdrawal and corticosteroids constituted the mainstay of DRESS treatment. We describe a 6 year-old boy who presented fever and rash 4 weeks after starting carbamazepine. Investigation revealed leukocytosis, atypical lymphocytosis, and elevated serum transaminases. The diagnosis of DREES syndrome was made, Carbamazepine was stopped and replaced initially by Clobazam and by Valproic acid after discharge, no systemic corticotherapy was prescribed. Symptoms began to resolve within two weeks, and by one month later her laboratory values had returned to normal. The aim of this work is to raise awareness general practitioner and pediatricians to suspect Dress syndrome in patients who present with unusual complaints and skin findings after starting any antiepileptic drug. PMID:25360193

  7. Drug Reaction with Eosinophilia and Systemic Symptom (DRESS) induced by carbamazepine: a case report and literature review.

    PubMed

    E L omairi, Nissrine; Abourazzak, Sanae; Chaouki, Sanae; Atmani, Samir; Hida, Moustapha

    2014-01-01

    Drug-induced hypersensitivity or Drug Reaction with Eosinophilia and Systemic Symptom (DRESS) is a severe adverse drug-induced reaction. Diagnosing DRESS is challenging due to the diversity of cutaneous eruption and organs involved. Most of the aromatic anticonvulsants, such as phenytoin, phenobarbital, and carbamazepine, can induce DRESS. Culprit drug withdrawal and corticosteroids constituted the mainstay of DRESS treatment. We describe a 6 year-old boy who presented fever and rash 4 weeks after starting carbamazepine. Investigation revealed leukocytosis, atypical lymphocytosis, and elevated serum transaminases. The diagnosis of DREES syndrome was made, Carbamazepine was stopped and replaced initially by Clobazam and by Valproic acid after discharge, no systemic corticotherapy was prescribed. Symptoms began to resolve within two weeks, and by one month later her laboratory values had returned to normal. The aim of this work is to raise awareness general practitioner and pediatricians to suspect Dress syndrome in patients who present with unusual complaints and skin findings after starting any antiepileptic drug.

  8. Capture and Fusion-Fission Processes in Heavy Ion Induced Reactions

    NASA Astrophysics Data System (ADS)

    Itkis, M. G.; Beghini, S.; Behera, B. R.; Bogatchev, A. A.; Bouchat, V.; Corradi, L.; Dorvaux, O.; Fioretto, E.; Gadea, A.; Hanappe, F.; Itkis, I. M.; Jandel, M.; Kliman, J.; Knyazheva, G. N.; Kondratiev, N. A.; Kozulin, E. M.; Krupa, L.; Latina, A.; Lyapin, V. G.; Materna, T.; Montagnoli, G.; Oganessian, Yu. Ts.; Pokrovsky, I. V.; Prokhorova, E. V.; Rowley, N.; Rubchenya, V. A.; Rusanov, A. Ya.; Sagaidak, R. N.; Scarlassara, F.; Schmitt, C.; Stefanini, A. M.; Stuttge, L.; Szilner, S.; Trotta, M.; Trzaska, W. H.; Voskresenski, V. M.

    2005-11-01

    Results of the experiments aimed at the study of fission and quasi-fission processes in the reactions 12C+204Pb, 48Ca+144,154Sm, 168Er, 208Pb, 238U, 244Pu, 248Cm; 58Fe+208Pb, 244Pu, 248Cm, and 64Ni+186W, 242Pu are presented. The choice of the above-mentioned reactions was inspired by the experiments on the production of the isotopes 283112, 289114 and 283116 at Dubna using the same reactions. The 58Fe and 64Ni projectiles were chosen since the corresponding projectile-target combinations lead to the synthesis of even heavier elements. The experiments were carried out at the U-400 accelerator of the Flerov Laboratory of Nuclear Reactions (JINR, Russia), the XTU Tandem accelerator of the National Laboratory of Legnaro (LNL, Italy) and the Accelerator of the Laboratory of University of Jyvaskyla (JYFL, Finland) using the time-of-flight spectrometer of fission fragments CORSET and the neutron multi-detector DEMON. The role of shell effects and the influence of the entrance channel asymmetry and the deformations of colliding nucleus on the mechanism of the fusion-fission and the competitive process of quasi-fission are discussed.

  9. Reaction dynamics induced by the radioactive ion beam {sup 7}Be on medium-mass and heavy targets

    SciTech Connect

    Mazzocco, M. Stefanini, C.; Strano, E.; Torresi, D.; Lay, J. A.; Molini, P.; Soramel, F.; Boiano, A.; Parascandolo, C.; Pierroutsakou, D.; Di Meo, P.; Boiano, C.; La Commara, M.; Sandoli, M.; Silvestri, R.; Manea, C.; Nicoletto, M.; Acosta, L.; Fernandez-Garcia, J. P.; Glodariu, T.; and others

    2015-10-15

    We studied the reaction dynamics induced at Coulomb barrier energies by the weakly-bound Radioactive Ion Beam {sup 7}Be (S{sub α} = 1.586 MeV) on medium-mass ({sup 58}Ni) and heavy ({sup 208}Pb) targets. The experiments were performed at INFN-LNL (Italy), where a 2-3×10{sup 5} pps {sup 7}Be secondary beam was produced with the RIB in-flight facility EXOTIC. Charged reaction products were detected by means of high-granularity silicon detectors in rather wide angular ranges. The contribution presents an up-to-date status of the data analysis and theoretical interpretation for both systems.

  10. Synthesis of Cu3Sn alloy nanocrystals through sequential reduction induced by gradual increase of the reaction temperature.

    PubMed

    Cho, Sanghun; Shin, Dong-Hun; Yin, Zhenxing; Lee, Chaedong; Park, Si Yun; Yoo, Jeeyoung; Piao, Yuanzhe; Kim, Youn Sang

    2015-04-27

    Cu3Sn alloy nanocrystals are synthesized by sequential reduction of Cu and Sn precursors through a gradual increase of the reaction temperature. By transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), UV/Vis spectroscopy, and X-ray diffraction (XRD) analyses, the alloy formation mechanism of Cu3Sn nanocrystals has been studied. The incremental increase of the reaction temperature sequentially induces the reduction of Sn, the diffusion of Sn into the preformed Cu nanocrystals, resulting in the intermediate phase of Cu-Sn alloy nanocrystals, and then the formation of Cu3Sn alloy nanocrystals. We anticipate that the synthesis of Cu3Sn alloy nanocrystals encourages studies toward the synthesis of various alloy nanomaterials.

  11. Reaction pattern and mechanism of light induced oxidative water splitting in photosynthesis.

    PubMed

    Renger, Gernot; Kühn, Philipp

    2007-06-01

    This mini review is an attempt to briefly summarize our current knowledge on light driven oxidative water splitting in photosynthesis. The reaction leading to molecular oxygen and four protons via photosynthesis comprises thermodynamic and kinetic constraints that require a balanced fine tuning of the reaction coordinates. The mode of coupling between electron (ET) and proton transfer (PT) reactions is shown to be of key mechanistic relevance for the redox turnover of Y(Z) and the reactions within the WOC. The WOC is characterized by peculiar energetics of its oxidation steps in the WOC. In all oxygen evolving photosynthetic organisms the redox state S(1) is thermodynamically most stable and therefore this general feature is assumed to be of physiological relevance. Available information on the Gibbs energy differences between the individual redox states S(i+1) and S(i) and on the activation energies of their oxidative transitions are used to construct a general reaction coordinate of oxidative water splitting in photosystem II (PS II). Finally, an attempt is presented to cast our current state of knowledge into a mechanism of oxidative water splitting with special emphasis on the formation of the essential O-O bond and the active role of the protein environment in tuning the local proton activity that depends on time and redox state S(i). The O-O linkage is assumed to take place within a multistate equilibrium at the redox level of S(3), comprising both redox isomerism and proton tautomerism. It is proposed that one state, S(3)(P), attains an electronic configuration and nuclear geometry that corresponds with a hydrogen bonded peroxide which acts as the entatic state for the generation of complexed molecular oxygen through S(3)(P) oxidation by Y(Z)(ox).

  12. Modification of structural and magnetic properties of soft magnetic multi-component metallic glass by 80 MeV 16O6+ ion irradiation

    NASA Astrophysics Data System (ADS)

    Kane, S. N.; Shah, M.; Satalkar, M.; Gehlot, K.; Kulriya, P. K.; Avasthi, D. K.; Sinha, A. K.; Modak, S. S.; Ghodke, N. L.; Reddy, V. R.; Varga, L. K.

    2016-07-01

    Effect of 80 MeV 16O6+ ion irradiation in amorphous Fe77P8Si3C5Al2Ga1B4 alloy is reported. Electronic energy loss induced modifications in the structural and, magnetic properties were monitored by synchrotron X-ray diffraction (SXRD), Mössbauer and, magnetic measurements. Broad amorphous hump seen in SXRD patterns reveals the amorphous nature of the studied specimens. Mössbauer measurements suggest that: (a) alignment of atomic spins within ribbon plane, (b) changes in average hyperfine field suggests radiation-induced decrease in the inter atomic distance around Mössbauer (Fe) atom, (c) hyperfine field distribution confirms the presence of non-magnetic elements (e.g. - B, P, C) in the first near-neighbor shell of the Fe atom, thus reducing its magnetic moment, and (d) changes in isomer shift suggests variation in average number of the metalloid near neighbors and their distances. Minor changes in soft magnetic behavior - watt loss and, coercivity after an irradiation dose of 2 × 1013 ions/cm2 suggests prospective application of Fe77P8Si3C5Al2Ga1B4 alloy as core material in accelerators (radio frequency cavities).

  13. Reactive Transport Modeling of Induced Calcite Precipitation Reaction Fronts in Porous Media Using A Parallel, Fully Coupled, Fully Implicit Approach

    NASA Astrophysics Data System (ADS)

    Guo, L.; Huang, H.; Gaston, D.; Redden, G. D.; Fox, D. T.; Fujita, Y.

    2010-12-01

    Inducing mineral precipitation in the subsurface is one potential strategy for immobilizing trace metal and radionuclide contaminants. Generating mineral precipitates in situ can be achieved by manipulating chemical conditions, typically through injection or in situ generation of reactants. How these reactants transport, mix and react within the medium controls the spatial distribution and composition of the resulting mineral phases. Multiple processes, including fluid flow, dispersive/diffusive transport of reactants, biogeochemical reactions and changes in porosity-permeability, are tightly coupled over a number of scales. Numerical modeling can be used to investigate the nonlinear coupling effects of these processes which are quite challenging to explore experimentally. Many subsurface reactive transport simulators employ a de-coupled or operator-splitting approach where transport equations and batch chemistry reactions are solved sequentially. However, such an approach has limited applicability for biogeochemical systems with fast kinetics and strong coupling between chemical reactions and medium properties. A massively parallel, fully coupled, fully implicit Reactive Transport simulator (referred to as “RAT”) based on a parallel multi-physics object-oriented simulation framework (MOOSE) has been developed at the Idaho National Laboratory. Within this simulator, systems of transport and reaction equations can be solved simultaneously in a fully coupled, fully implicit manner using the Jacobian Free Newton-Krylov (JFNK) method with additional advanced computing capabilities such as (1) physics-based preconditioning for solution convergence acceleration, (2) massively parallel computing and scalability, and (3) adaptive mesh refinements for 2D and 3D structured and unstructured mesh. The simulator was first tested against analytical solutions, then applied to simulating induced calcium carbonate mineral precipitation in 1D columns and 2D flow cells as analogs

  14. The sudden onset of mastocytosis in the course of venom-induced anaphylactic reaction in a patient with myelodysplastic syndrome.

    PubMed

    Rybicka, Malwina; Helbig, Grzegorz; Woźniczka, Krzysztof; Kopera, Małgorzata; Pająk, Jacek; Kyrcz-Krzemień, Sławomira

    2015-01-01

    Mastocytosis is a disease resulting from a proliferation of clonal, abnormal mast cells in tissues and organs, defined as Philadelphia-negative myeloproliferative neoplasm. We present a male patient with clinically, morphologically and immunohistochemically confirmed mastocytosis with preceding myelodysplastic syndrome, occurred after wasp bite in the course of anaphylactic reaction. The propensity to hymenoptera venom-induced anaphylaxis and the presence of an increased population of atypical mast cells in bone marrow found after anaphylactic shock may suggest the possible relationship between hymenoptera venom allergy and anaphylaxis and the development of mastocytosis of unusual course in a predisposed person.

  15. Galerkin analysis of light-induced patterns in the chlorine dioxide-iodine-malonic acid reaction-diffusion system

    NASA Astrophysics Data System (ADS)

    Ghosh, Pushpita; Sen, Shrabani; Riaz, Syed Shahed; Ray, Deb Shankar

    2009-05-01

    The photosensitive chlorine dioxide-iodine-malonic acid reaction-diffusion system has been an experimental paradigm for the study of Turing pattern over the last several years. When subjected to illumination of varied intensity by visible light the patterns undergo changes from spots to stripes, vice versa, and their mixture. We carry out a nonlinear analysis of the underlying model in terms of a Galerkin scheme with finite number of modes to explore the nature of the stability and existence of various modes responsible for the type and crossover of the light-induced patterns.

  16. The design of dextran-based hypoxia-inducible hydrogels via in situ oxygen-consuming reaction.

    PubMed

    Park, Kyung Min; Blatchley, Michael R; Gerecht, Sharon

    2014-11-01

    Hypoxia plays a critical role in the development and wound healing process, as well as a number of pathological conditions. Here, dextran-based hypoxia-inducible (Dex-HI) hydrogels formed with in situ oxygen consumption via a laccase-medicated reaction are reported. Oxygen levels and gradients were accurately predicted by mathematical simulation. It is demonstrated that Dex-HI hydrogels provide prolonged hypoxic conditions up to 12 h. The Dex-HI hydrogel offers an innovative approach to delineate not only the mechanism by which hypoxia regulates cellular responses, but may facilitate the discovery of new pathways involved in the generation of hypoxic and oxygen gradient environments.

  17. Exhaustive study of the noise-induced phase transition in a stochastic model of self-catalyzed reactions

    NASA Astrophysics Data System (ADS)

    Pham, T. M.; Virchenko, Yu. P.

    2016-08-01

    We completely investigate the stationary distribution density in the space of relative concentrations for the three-parameter stochastic Horsthemke-Lefever model of a binary self-catalyzed cyclic chemical reaction with perturbations produced by thermal fluctuations of reagents taken into account. This model is a stationary diffusion random process generated by a stochastic equation with the Stratonovich differential, whose marginal distribution density admits a bifurcation restructuring from the unimodal to the bimodal phase with increasing noise intensity, which is interpreted physically as a dynamical phase transition induced by fluctuations in the system.

  18. Stationary Vortex Loops Induced by Filament Interaction and Local Pinning in a Chemical Reaction-Diffusion System

    NASA Astrophysics Data System (ADS)

    Jiménez, Zulma A.; Steinbock, Oliver

    2012-08-01

    Scroll rings are three-dimensional excitation waves rotating around one-dimensional filament loops. In experiments with the Belousov-Zhabotinsky reaction we show that the collapse of these loops can be stopped by local pinning to only two unexcitable heterogeneities. The resulting vortices rotate around stationary but curved filaments. The absence of filament motion can be explained by repulsive interaction that counteracts the expected curvature-induced motion. The shape and key dependencies of the stationary filaments are well described by a curvature-flow model with additive interaction velocities that rapidly decrease with filament distance.

  19. Validation of GEANT4 simulations for 62,63Zn yield estimation in proton induced reactions of natural copper

    NASA Astrophysics Data System (ADS)

    Rostampour, Malihe; Sadeghi, Mahdi; Aboudzadeh, Mohammadreza; Hamidi, Saeid; Hosseini, Seyedeh Fatemeh

    2017-03-01

    A useful approach to optimize of radioisotope production is the use of Monte Carlo simulations prior to experimentation. In this paper, the GEANT4 code was employed to calculate the saturation yields of 62,63Zn from proton-induced reactions of natural copper, enriched 63Cu and 65Cu. In addition, the saturation yields of the investigated radio-nuclides were calculated using the stopping power from the SRIM-2013 and reported experimental data for cross sections. The simulated saturation yields were compared with experimental values. Good agreement between the experimental and corresponding simulated data demonstrated that GEANT4 provides a suitable tool for radionuclide simulation production using proton irradiation.

  20. Modeled Neutron Induced Nuclear Reaction Cross Sections for Radiochemsitry in the region of Thulium, Lutetium, and Tantalum I. Results of Built in Spherical Symmetry in a Deformed Region

    SciTech Connect

    Hoffman, R. D.

    2013-09-06

    We have developed a set of modeled nuclear reaction cross sections for use in radiochemical diagnostics. Systematics for the input parameters required by the Hauser-Feshbach statistical model were developed and used to calculate neutron induced nuclear reaction cross sections for targets ranging from Terbium (Z = 65) to Rhenium (Z = 75). Of particular interest are the cross sections on Tm, Lu, and Ta including reactions on isomeric targets.

  1. Thermally induced electrocyclic reaction of methylenecyclopropane methylene diketone derivatives: a facile method for the synthesis of spiro[2.5]octa-3,5-dienes.

    PubMed

    Tang, Xiang-Ying; Wei, Yin; Shi, Min

    2010-11-19

    Thermally induced electrocyclic reactions of methylenecyclopropane (MCP) methylene diketone derivatives afford a novel method for the synthesis of spiro[2.5]octa-3,5-dienes in moderate to good yields. Applying this methodology in a one-pot manner for the reactions of MCP aldehydes with 1,3-diketones, catalyzed by l-proline, also afforded the corresponding spiro derivatives.

  2. Platelet-activating factor in Iberian pig spermatozoa: receptor expression and role as enhancer of the calcium-induced acrosome reaction.

    PubMed

    Bragado, M J; Gil, M C; Garcia-Marin, L J

    2011-12-01

    Platelet-activating factor (PAF) is a phospholipid involved in reproductive physiology. PAF receptor is expressed in some mammalian spermatozoa species where it plays a role in these germ-cell-specific processes. The aim of this study is to identify PAF receptor in Iberian pig spermatozoa and to evaluate PAF's effects on motility, viability and acrosome reaction. Semen samples from Iberian boars were used. PAF receptor identification was performed by Western blotting. Spermatozoa motility was analysed by computer-assisted sperm analysis system, whereas spermatozoa viability and acrosome reaction were evaluated by flow cytometry. Different PAF concentrations added to non-capacitating medium during 60 min have no effect on any spermatozoa motility parameter measured. Acrosome reaction was rapid and potently induced by 1 μm calcium ionophore A23187 showing an effect at 60 min and maximum at 240 min. PAF added to a capacitating medium is not able to induce spermatozoa acrosome reaction at any time studied. However, PAF, in the presence of A23187, significantly accelerates and enhances the calcium-induced acrosome reaction in a concentration-dependent manner in Iberian boar spermatozoa. Exogenous PAF does not affect at all spermatozoa viability, whereas slightly exacerbated the A23187-induced loss in viability. This work demonstrates that PAF receptor is expressed in Iberian pig spermatozoa and that its stimulation by PAF regulates the calcium-induced acrosome reaction. This work contributes to further elucidate the physiological regulation of the most relevant spermatozoa functions for successful fertilization: acrosome reaction.

  3. A rapid vectorial back reaction at the reaction centers of photosystem II in tris-washed chloroplasts induced by repetitive flash excitation.

    PubMed

    Renger, G

    1979-07-10

    In Tris-washed chloroplasts, completely lacking the oxygen-evolving capacity, absorption changes in the range of 420--560 nm induced by repetitive flash excitation have been measured in the presence and absence of electron donors. It was found: (1) At 520 nm flash-induced absorption changes are observed, which predominantly decay via a 100--200-mus exponential kinetics corresponding to that of the back reaction between the primary electron donor and acceptor of Photosystem II (Haveman, J. and Mathis, P. (1976) Biochim. Biophys. Acta 440, 346--355; Renger, G. and Wolff, Ch. (1976) Biochim. Biophys. Acta 423, 610--614). In the presence of hydroquinone/ascorbate as donor couple the amplitude is nearly doubled and the decay becomes significantly slowed down. (2) The difference spectrum of the absorption changes obtained in the presence of hydroquinone/ascorbate, which are sensitive to ionophores, is nearly identical with that of normal chloroplasts in the range of 460--560 nm (Emrich, H.M., Junge, W. and Witt, H.T. (1969) Z. Naturforsch. 24b, 114--1146). In the absence of hydroquinone/ascorbate the difference spectrum of the absorption changes, characterized by a 100--200-mus decay kinetics, differs in the range of 460--500 nm and by a hump in the range of 530--560 nm. The hump is shown to be attributable to the socalled C550 absorption change, which reflects the turnover of the primary acceptor of Photosystem II (van Gorkom, H.J.(1976) Thesis, Leiden), while the deviations in the range of 460--500 nm are understandable as to be due to the overlapping absorption changes of chlorphyll alpha II+. The problems arising with the latter explanation are discussed. (3) The electron transfer due to the rapid turnover at Photosystem II, which can be induced by flash groups with a short dark time between the flashes, is not able to energize the ATPase and to drive photophosphorylation. On the basis of the present results it is inferred, that in Tris-washed chloroplasts under

  4. Emergent Properties of Giant Vesicles Formed by a Polymerization-Induced Self-Assembly (PISA) Reaction

    PubMed Central

    Albertsen, Anders N.; Szymański, Jan K.; Pérez-Mercader, Juan

    2017-01-01

    Giant micrometer sized vesicles are of obvious interest to the natural sciences as well as engineering, having potential application in fields ranging from drug delivery to synthetic biology. Their formation often requires elaborate experimental techniques and attempts to obtain giant vesicles from chemical media in a one-pot fashion have so far led to much smaller nanoscale structures. Here we show that a tailored medium undergoing controlled radical polymerization is capable of forming giant polymer vesicles. Using a protocol which allows for an aqueous reaction under mild conditions, we observe the macroscale consequences of amphiphilic polymer synthesis and the resulting molecular self-assembly using fluorescence microscopy. The polymerization process is photoinitiated by blue light granting complete control of the reaction, including on the microscope stage. The self-assembly process leads to giant vesicles with radii larger than 10 microns, exhibiting several emergent properties, including periodic growth and collapse as well as phototaxis. PMID:28128307

  5. Dichotomous-noise-induced pattern formation in a reaction-diffusion system

    NASA Astrophysics Data System (ADS)

    Das, Debojyoti; Ray, Deb Shankar

    2013-06-01

    We consider a generic reaction-diffusion system in which one of the parameters is subjected to dichotomous noise by controlling the flow of one of the reacting species in a continuous-flow-stirred-tank reactor (CSTR) -membrane reactor. The linear stability analysis in an extended phase space is carried out by invoking Furutzu-Novikov procedure for exponentially correlated multiplicative noise to derive the instability condition in the plane of the noise parameters (correlation time and strength of the noise). We demonstrate that depending on the correlation time an optimal strength of noise governs the self-organization. Our theoretical analysis is corroborated by numerical simulations on pattern formation in a chlorine-dioxide-iodine-malonic acid reaction-diffusion system.

  6. Enantioselective Visible-Light-Induced Radical-Addition Reactions to 3-Alkylidene Indolin-2-ones.

    PubMed

    Lenhart, Dominik; Bauer, Andreas; Pöthig, Alexander; Bach, Thorsten

    2016-05-04

    The title compounds underwent a facile and high-yielding addition reaction (19 examples, 66-99% yield) with various N-(trimethylsilyl)methyl-substituted amines upon irradiation with visible light and catalysis by a metal complex. If the alkylidene substituent is non-symmetric and if the reaction is performed in the presence of a chiral hydrogen-bonding template, products are obtained with significant enantioselectivity (58-72% ee) as a mixture of diastereoisomers. Mechanistic studies suggest a closed catalytic cycle for the photoactive metal complex. However, the silyl transfer from the amine occurs not only to the product, but also to the substrate, and interferes with the desired chirality transfer.

  7. Population of collective bands in Dy isotopes using heavy ion induced transfer reactions

    SciTech Connect

    Cresswell, A.J.; Butler, P.A.; Cline, D.; Cunningham, R.A.; Devlin, M.; Hannachi, F.; Ibbotson, R.; Jones, G.D.; Jones, P.M.; Simon, M.; Simpson, J.; Smith, J.F.; Wu, C.Y. ||

    1995-10-01

    It is demonstrated that low-lying collective bands in deformed nuclei are strongly populated by quasielastic heavy ion transfer reactions at near barrier energies. The {sup 161}Dy({sup 61}Ni,{sup 62}Ni){sup 160}Dy and {sup 161}Dy({sup 61}Ni,{sup 60}Ni){sup 162}Dy reactions at a beam energy of 270 MeV have been studied using a particle-{gamma} technique. Significant population of sidebands in {sup 160}Dy was observed, particularly the {ital S} band built upon the [{nu}({ital i}{sub 13/2})]{sup 2} configuration and the {ital K}{sup {pi}}=1{sup {minus}}, 2{sup {minus}}, and {gamma} bands. For {sup 162}Dy the only sideband significantly populated was the {gamma} band.

  8. Generation of cavitation luminescence by laser-induced exothermic chemical reaction

    SciTech Connect

    Jung Park, Han; Diebold, Gerald J.

    2013-08-14

    Absorption of high power laser radiation by aqueous carbon suspensions is known to result in the formation of highly compressed bubbles of hydrogen and carbon monoxide through the endothermic carbon-steam reaction. The bubbles expand rapidly, overreaching their equilibrium diameter, and then collapse tens to hundreds of microseconds after formation to give a flash of radiation. Here we report on the effects of laser-initiated exothermic chemical reaction on cavitation luminescence. Experiments with hydrogen peroxide added to colloidal carbon suspensions show that both the time of the light flash following the laser pulse and the intensity of luminescence increase with hydrogen peroxide concentration, indicating that large, highly energetic gas bubbles are produced. Additional experiments with colloidal carbon suspensions show the effects of high pressure on the luminescent intensity and its time of appearance following firing of the laser.

  9. Emergent Properties of Giant Vesicles Formed by a Polymerization-Induced Self-Assembly (PISA) Reaction

    NASA Astrophysics Data System (ADS)

    Albertsen, Anders N.; Szymański, Jan K.; Pérez-Mercader, Juan

    2017-01-01

    Giant micrometer sized vesicles are of obvious interest to the natural sciences as well as engineering, having potential application in fields ranging from drug delivery to synthetic biology. Their formation often requires elaborate experimental techniques and attempts to obtain giant vesicles from chemical media in a one-pot fashion have so far led to much smaller nanoscale structures. Here we show that a tailored medium undergoing controlled radical polymerization is capable of forming giant polymer vesicles. Using a protocol which allows for an aqueous reaction under mild conditions, we observe the macroscale consequences of amphiphilic polymer synthesis and the resulting molecular self-assembly using fluorescence microscopy. The polymerization process is photoinitiated by blue light granting complete control of the reaction, including on the microscope stage. The self-assembly process leads to giant vesicles with radii larger than 10 microns, exhibiting several emergent properties, including periodic growth and collapse as well as phototaxis.

  10. Special features of isomeric ratios in nuclear reactions induced by various projectile particles

    NASA Astrophysics Data System (ADS)

    Danagulyan, A. S.; Hovhannisyan, G. H.; Bakhshiyan, T. M.; Martirosyan, G. V.

    2016-05-01

    Calculations for ( p, n) and (α, p3 n) reactions were performed with the aid of the TALYS-1.4 code. Reactions in which the mass numbers of target and product nuclei were identical were examined in the range of A = 44-124. Excitation functions were obtained for product nuclei in ground and isomeric states, and isomeric ratios were calculated. The calculated data reflect well the dependence of the isomeric ratios on the projectile type. A comparison of the calculated and experimental data reveals, that, for some nuclei in a high-spin state, the calculated data fall greatly short of their experimental counterparts. These discrepancies may be due to the presence of high-spin yrast states and rotational bands in these nuclei. Calculations involving various level-density models included in the TALYS-1.4 code with allowance for the enhancement of collective effects do not remove the discrepancies in the majority of cases.

  11. Dual-frequency oscillations induced by acidity in Belousov-Zhabotinskii reactions with aldosugars as substrates

    NASA Astrophysics Data System (ADS)

    Li, Hexing; Jin, Ronghua; Dai, Weilin; Deng, Jingfa

    1997-08-01

    Depending on the initial concentration of H 2SO 4, two types of dual-frequency oscillations have been observed in Belousov-Zhabotinskii type reactions catalyzed by Mn 2+ with acetone and aldosugars (arabinose, glucose, galactose, lactose or maltose) as coupled substrates in a batch reactor. No such dual-frequency oscillations have been found when a ketosugar like fructose was used instead of an aldosugar as the substrate; or acetone was replaced by N 2 flow. No oscillations were observed when Ce 3+ was used instead of Mn 2+. The reaction products of aldosugars in different oscillating regimes have been analyzed. The dual-frequency oscillatory patterns have been discussed according to the roles of the substrates and their derivatives formed at different acidity.

  12. Mycobacterium tuberculosis is extraordinarily sensitive to killing by a vitamin C-induced Fenton reaction

    PubMed Central

    Vilchèze, Catherine; Hartman, Travis; Weinrick, Brian; Jacobs, William R.

    2013-01-01

    Drugs that kill tuberculosis more quickly could shorten chemotherapy significantly. In Escherichia coli, a common mechanism of cell death by bactericidal antibiotics involves the generation of highly reactive hydroxyl radicals via the Fenton reaction. Here we show that vitamin C, a compound known to drive the Fenton reaction, sterilizes cultures of drug-susceptible and drug-resistant Mycobacterium tuberculosis, the causative agent of tuberculosis. While M. tuberculosis is highly susceptible to killing by vitamin C, other Gram-positive and Gram-negative pathogens are not. The bactericidal activity of vitamin C against M. tuberculosis is dependent on high ferrous ion levels and reactive oxygen species production and causes a pleiotropic effect affecting several biological processes. This study enlightens the possible benefits of adding vitamin C to an anti-tuberculosis regimen and suggests that the development of drugs that generate high oxidative burst could be of great use in tuberculosis treatment. PMID:23695675

  13. Level density and mechanism of deuteron-induced reactions on Fe54,56,58

    DOE PAGES

    Ramirez, A. P. D.; Voinov, A. V.; Grimes, S. M.; ...

    2015-07-06

    Here, deuteron elastic cross sections, as well as neutron, proton, and α-particle emission spectra, from d+54,56,58Fe reactions have been measured with deuteron beam energies of 5, 7, and 9 MeV. Optical model parameters have been tested against our experimental data. The fraction of total reaction cross section responsible for the formation of compound nuclei has been deduced from the angular distributions. The degree of discrepancy between calculated and experimental compound cross sections was found to increase with increasing neutron number. The nuclear level densities of the residual nuclei 55Co, 57Co, 55Fe, 57Fe, 52Mn, and 54Mn have been deduced from themore » compound double differential cross sections. The Gilbert-Cameron model with Iljinov parameter systematics [A. S. Iljinov and M. V. Mebel, Nucl. Phys. A 543, 517 (1992)] was found to have a good agreement with our results.« less

  14. Chemical reactions induced by high-velocity molecular impacts: challenges for closed-source mass spectrometry

    NASA Astrophysics Data System (ADS)

    Austin, Daniel

    2016-07-01

    Analysis of upper atmosphere composition using closed-source neutral mass spectrometers (e.g., Cassini INMS, MAVEN NGIMS) is subject to error due to chemical reactions caused by the high-velocity impacts of neutral molecules on the source surfaces. In addition to species traditionally considered "surface reactive" (e.g., O, N) it is likely that many or all impacting molecules are vibrationally excited to the point that chemical changes can occur. Dissociation, fragmentation, formation of radicals and ions, and other reactions likely obscure analysis of the native atmospheric composition, particularly of organic compounds. Existing techniques are not capable of recreating the relevant impact chemistry in the lab. We report on the development of a new capability allowing reactions of high-velocity neutrals impacting surfaces to be characterized directly. Molecules introduced into a vacuum chamber are impacted at several km/s by the surface of a high-speed rotor. These molecules subsequently impact multiple times on other surfaces within the vacuum chamber until they are thermalized, after which they are cryogenically collected and analyzed. Reaction pathways and thermodynamics for volatile compounds are then determined. We will present current results on this project, including data from low- and mid-range velocity experiments. This type of information is critical to clarify prior flight results and plan for future missions. Finally, we present a new type of inlet intended to significantly reduce fragmentation for impact velocities typical of a fly-by mission. Theoretical analysis indicates that this new inlet may reduce fragmentation by more than an order of magnitude for any encounter velocity.

  15. Remediation of Cu metal-induced accelerated Fenton reaction by potato peels bio-sorbent.

    PubMed

    Azmat, Rafia; Moin, Sumeira; Saleem, Ailyan

    2016-12-01

    This article has allied exposure to Ecological Particulate Matter (EPM) and its remediation using potato peel surface (PPC) bio-sorbent on two important edible crops Spinacia oleracea and Luffa acutangula. Fenton reaction acceleration was one of the major stress oxidation reactions as a consequence of iron and copper toxicity, which involve in the formation of hydroxyl radical (OH) through EPM. Results showed that the oxidative stress encouraged by Cu in both species that recruits the degradation of photosynthetic pigments, initiating decline in growth, reduced leaf area and degrade proteins. The plants were cultivated in natural environmental condition in three pots with three replicates like (a) control, (b) Cu treated and (c) treated water. Oxidative stress initiated by metal activity in Cu accumulated plant (b) were controlled, through bio-sorption of metal from contaminated water using PPC; arranged at laboratory scale. The acceleration of Fenton reaction was verified in terms of OH radical generation. These radicals were tested in aqueous extract of leaves of three types of plants via benzoic acid. The benzoic acid acts as a scavenger of OH radical due to which the decarboxylation of benzoic acid cured. Observation on (b) showed more rapid decarboxylation as compared to other plants which showed that Cu activity was much higher in (b) as compared to (a) and (c). The rapid decarboxylation of benzoic acid and lower chlorophyll contents in (b) suggest that Fenton reaction system was much enhanced by Cu-O and Fe-O chemistry that was successfully controlled by PPC which results in restoring the metabolic pathway and nullifying oxidative stress in

  16. Coenzyme Q10 Suppresses TNF-α-Induced Inflammatory Reaction In Vitro and Attenuates Severity of Dermatitis in Mice.

    PubMed

    Li, Weiwei; Wu, Xiaojuan; Xu, Xiangling; Wang, Wenhan; Song, Sijia; Liang, Ke; Yang, Min; Guo, Linlin; Zhao, Yunpeng; Li, Ruifeng

    2016-02-01

    Anti-oxidant coenzyme Q10 (Co-Q10) is commonly used in clinic. Recently, Co-Q10 was reported to antagonize TNF-α-induced inflammation and play a protective role in various inflammatory conditions. However, its role in dermatitis is unknown. Herein, RAW264.7 macrophage cell line was cultured with stimulation of TNF-α, and administration of Co-Q10 alleviated TNF-α-mediated inflammatory reaction in vitro. Furthermore, oxazolone-induced dermatitis mice model was established, and treatment of Co-Q10 markedly attenuated dermatitis phenotype in this mice model. Moreover, the protective role of Co-Q10 in vitro and in dermatitis was probably due to its repression on NF-κB signaling. Collectively, Co-Q10 may represent a potential molecular target for prevention and treatment of inflammatory skin diseases.

  17. Effect of CO2-induced reactions on the mechanical behaviour of fractured wellbore cement

    NASA Astrophysics Data System (ADS)

    Wolterbeek, Timotheus; Hangx, Suzanne; Spiers, Christopher

    2016-04-01

    Geomechanical damage, such as fracturing of wellbore cement, can severely impact well integrity in CO2 storage fields. Chemical reactions between the cement and CO2-bearing fluids may subsequently alter the cement's mechanical properties, either enhancing or inhibiting damage accumulation during ongoing changes in wellbore temperature and stress-state. To evaluate the potential for such effects, we performed triaxial compression tests on Class G Portland cement, conducted at down-hole temperature (80 ° C) and effective confining pressures ranging from 1 to 25 MPa. After deformation, samples displaying failure on localised shear fractures were reacted with CO2-H2O, and then subjected to a second triaxial test to assess changes in mechanical properties. Using results from the first phase of deformation, baseline yield and failure criteria were constructed for virgin cement. These delineate stress conditions where unreacted cement is most prone to dilatational (permeability-enhancing) failure. Once shear-fractures formed, later reaction with CO2 did not produce further geomechanical weakening. Instead, after six weeks of reaction, we observed up to 83% recovery of peak-strength and increased frictional strength (15-40%) in the post-failure regime, due to calcium carbonate precipitation in the fractures. As such, our results suggest more or less complete mechanical healing on timescales of the order of months.

  18. Ionizing radiation at low doses induces inflammatory reactions in human blood.

    PubMed

    Vicker, M G; Bultmann, H; Glade, U; Häfker, T

    1991-12-01

    Irradiation of whole blood with 137Cs gamma rays intensifies the oxidative burst. Oxidant production was used as an indicator of inflammatory cell reactions and was measured by luminol-amplified chemiluminescence after treatment with inflammatory activators including bacteria, the neutrophil taxin formyl-Met-Leu-Phe, the Ca2+ ionophore A23187, the detergent saponin, and the tumor promoter phorbol ester. The irradiation response is dose-dependent up to about 100 microGy, is detectable within minutes, persists at least 1 h, and is transmitted intercellularly by a soluble mediator. The response is completely inhibited by Ca2+ sequestration in the presence of A23187 or by adenosine, indicating its Ca2+ dependency, and by the phospholipase A2 blocker p-bromphenacyl bromide. However, inhibition by the cyclooxygenase blocker aspirin is sporadic or absent. Blood taken after diagnostic examination of lungs with X rays also exhibited intensified chemiluminescence. These reactions implicate a role for specific amplifying mediator pathways, especially metabolites of the arachidonic acid cascade, in the response: "damage and repair" to cells or DNA plays little or no role. Our results provide evidence for a new mechanism of radiation action with possible consequences for the homeostasis of reactions involving inflammation and second messengers in human health and early development.

  19. Production of neutron-rich transcalifornium nuclei in 238U-induced transfer reactions

    NASA Astrophysics Data System (ADS)

    Zhu, Long; Su, Jun; Xie, Wen-Jie; Zhang, Feng-Shou

    2016-11-01

    In order to produce more unknown neutron-rich transcalifornium nuclei, the collisions of 238U with the targets 248Cm, 249Cf, and 250Cm are investigated within the framework of the dinuclear system model. The production cross sections of unknown neutron-rich nuclei with Z =99 -104 in these reactions are predicted. The influences of N /Z ratios and charge numbers of the targets on the production cross sections are studied. It is found that high N /Z ratios of 248Cm and 250Cm targets enhance the production cross sections of neutron-rich transcalifornium nuclei. However, due to high charge number of the target 249Cf the predicted production cross sections of unknown neutron-rich nuclei with Z =104 in the reaction 238U+249Cf are higher than those in 238U+248Cm . We also have studied the entrance angular momentum effects on production probabilities of transfer products in the reaction 238U+248Cm . It is found that the formation probabilities of the final neutron-rich products increase first and then decrease with the increasing J .

  20. Neutron transfer reactions induced by {sup 8}Li on {sup 9}Be

    SciTech Connect

    Guimaraes, V.; Lichtenthaeler, R.; Camargo, O.; Barioni, A.; Assuncao, M.; Kolata, J. J.; Amro, H.; Becchetti, F. D.; Jiang, Hao; Aguilera, E. F.; Lizcano, D.; Martines-Quiroz, E.; Garcia, H.

    2007-05-15

    Angular distributions for the elastic scattering of {sup 8}Li on {sup 9}Be and the neutron transfer reactions {sup 9}Be({sup 8}Li,{sup 7}Li){sup 10}Be and {sup 9}Be({sup 8}Li,{sup 9}Li){sup 8}Be were measured with a 27 MeV {sup 8}Li radioactive nuclear beam. Spectr- oscopic factors for {sup 8}Li (multiply-in-circle sign)n{sup 9}Li and {sup 7}Li (multiply-in-circle sign)n{sup 8}Li bound systems were obtained from the comparison between the experimental differential cross section and finite-range distorted-wave Born approximation calculations with the code FRESCO. The spectroscopic factors obtained were compared to shell model calculations and to other experimental values from (d,p) reactions. Using the present values for the spectroscopic factor, cross sections for the direct neutron-capture reactions {sup 7}Li(n,{gamma}){sup 8}Li and {sup 8}Li(n,{gamma}){sup 9}Li were calculated in the framework of a potential model.

  1. Measurement of alpha-induced reaction cross sections on erbium isotopes for γ process studies

    NASA Astrophysics Data System (ADS)

    Kiss, G. G.; Szücs, T.; Török, Zs.; Fülöp, Zs.; Gyürky, Gy.; Halász, Z.; Somorjai, E.; Rauscher, T.

    2014-05-01

    The cross sections of the 162Er(α,γ)166Yb and 162,164,166Er(α,n)165,167,169Yb reactions have been measured at MTA Atomki. The radiative alpha capture reaction cross section was measured between Ec.m. = 11.21 MeV and Ec.m. = 16.09 MeV just above the astrophysically relevant energy region (which lies between 7.8 and 11.48 MeV at T9 = 3 GK). The 162Er(α,n)165Yb, 164Er(α,n)167Yb and 166Er(α,n)169Yb reactions were studied between Ec.m. = 12.19 and 16.09 MeV, Ec.m. = 13.17 and 16.59 MeV and Ec.m. = 12.68 and 17.08 MeV, respectively. The aim of this work is to provide experimental data for modeling the γ process which is thought to be responsible for the production of the proton-rich isotopes heavier than iron.

  2. Simultaneous measurement of neutron-induced capture and fission reactions at CERN

    NASA Astrophysics Data System (ADS)

    Guerrero, C.; Berthoumieux, E.; Cano-Ott, D.; Mendoza, E.; Andriamonje, S.; Andrzejewski, J.; Audouin, L.; Barbagallo, M.; Bécares, V.; Bečvář, F.; Belloni, F.; Billowes, J.; Brugger, M.; Calviani, M.; Calviño, F.; Carrapiço, C.; Cerutti, F.; Chiaveri, E.; Chin, M.; Colonna, N.; Cortés, G.; Cortés-Giraldo, M. A.; Diakaki, M.; Dillmann, I.; Domingo-Pardo, C.; Duran, I.; Eleftheriadis, C.; Fernández-Ordóñez, M.; Ferrari, A.; Ganesan, S.; Giubrone, G.; Gómez-Hornillos, M. B.; Gonçalves, I. F.; González-Romero, E.; Gramegna, F.; Griesmayer, E.; Gunsing, F.; Jenkins, D.; Jericha, E.; Kadi, Y.; Käppeler, F.; Karadimos, D.; Kroll, J.; Krtička, M.; Lebbos, E.; Lederer, C.; Leeb, H.; Losito, R.; Lozano, M.; Manousos, A.; Marganiec, J.; Marrone, S.; Martinez, T.; Massimi, C.; Mastinu, P. F.; Meaze, M.; Mengoni, A.; Milazzo, P. M.; Paradela, C.; Pavlik, A.; Perkowski, J.; Plag, R.; Praena, J.; Quesada, J. M.; Rauscher, T.; Reifarth, R.; Roman, F.; Rubbia, C.; Sarmento, R.; Tagliente, G.; Tain, J. L.; Tarrío, D.; Tassan-Got, L.; Tsinganis, A.; Vannini, G.; Variale, V.; Vaz, P.; Ventura, A.; Vermeullen, M.; Vlachoudis, V.; Vlastou, R.; Wallner, A.; Ware, T.; Weiß, C.; Wright, T.

    2012-03-01

    The measurement of the capture cross-section of fissile elements, of utmost importance for the design of innovative nuclear reactors and the management of nuclear waste, faces particular difficulties related to the γ -ray background generated in the competing fission reactions. At the CERN neutron time-of-flight facility n_TOF we have combined the Total Absorption Calorimeter (TAC) capture detector with a set of three 235U loaded MicroMegas (MGAS) fission detectors for measuring simultaneously two reactions: capture and fission. The results presented here include the determination of the three detection efficiencies involved in the process: ensuremath \\varepsilon_{TAC}(n,f) , ensuremath \\varepsilon_{TAC}(n,γ) and ensuremath \\varepsilon_{MGAS}(n,f) . In the test measurement we have succeeded in measuring simultaneously with a high total efficiency the 235U capture and fission cross-sections, disentangling accurately the two types of reactions. The work presented here proves that accurate capture cross-section measurements of fissile isotopes are feasible at n_TOF.

  3. Measurement of alpha-induced reaction cross sections on erbium isotopes for γ process studies

    SciTech Connect

    Kiss, G. G.; Szücs, T.; Török, Zs.; Fülöp, Zs.; Gyürky, Gy.; Halász, Z.; Somorjai, E.; Rauscher, T.

    2014-05-02

    The cross sections of the {sup 162}Er(α,γ){sup 166}Yb and {sup 162,164,166}Er(α,n){sup 165,167,169}Yb reactions have been measured at MTA Atomki. The radiative alpha capture reaction cross section was measured between E{sub c.m.} = 11.21 MeV and E{sub c.m.} = 16.09 MeV just above the astrophysically relevant energy region (which lies between 7.8 and 11.48 MeV at T{sub 9} = 3 GK). The {sup 162}Er(α,n){sup 165}Yb, {sup 164}Er(α,n){sup 167}Yb and {sup 166}Er(α,n){sup 169}Yb reactions were studied between E{sub c.m.} = 12.19 and 16.09 MeV, E{sub c.m.} = 13.17 and 16.59 MeV and E{sub c.m.} = 12.68 and 17.08 MeV, respectively. The aim of this work is to provide experimental data for modeling the γ process which is thought to be responsible for the production of the proton-rich isotopes heavier than iron.

  4. New potentialities of the Liège intranuclear cascade model for reactions induced by nucleons and light charged particles

    NASA Astrophysics Data System (ADS)

    Boudard, A.; Cugnon, J.; David, J.-C.; Leray, S.; Mancusi, D.

    2013-01-01

    The new version (incl4.6) of the Liège intranuclear cascade (INC) model for the description of spallation reactions is presented in detail. Compared to the standard version (incl4.2), it incorporates several new features, the most important of which are: (i) the inclusion of cluster production through a dynamical phase space coalescence model, (ii) the Coulomb deflection for entering and outgoing charged particles, (iii) the improvement of the treatment of Pauli blocking and of soft collisions, (iv) the introduction of experimental threshold values for the emission of particles, (v) the improvement of pion dynamics, (vi) a detailed procedure for the treatment of light-cluster-induced reactions taking care of the effects of binding energy of the nucleons inside the incident cluster and of the possible fusion reaction at low energy. Performances of the new model concerning nucleon-induced reactions are illustrated by a comparison with experimental data covering total reaction cross sections, neutron, proton, pion, and composite double-differential cross-sections, neutron multiplicities, residue mass and charge distributions, and residue recoil velocity distributions. Whenever necessary, the incl4.6 model is coupled to the ABLA07 de-excitation model and the respective merits of the two models are then tentatively disentangled. Good agreement is generally obtained in the 200 MeV to 2 GeV range. Below 200 MeV and down to a few tens of MeV, the total reaction cross section is well reproduced and differential cross sections are reasonably well described. The model is also tested for light-ion induced reactions at low energy, below 100 MeV incident energy per nucleon. Beyond presenting the update of the incl4.2 model, attention has been paid to applications of the new model to three topics for which some particular aspects are discussed for the first time. The first topic is the production of clusters heavier than alpha particle. It is shown that the energy spectra of

  5. SU-E-J-142: Prompt Gamma Emission Measurements From a Passively Scattered Proton Beam On Targets Containing 16O, 12C and 14N

    SciTech Connect

    Jeyasugiththan, J; Peterson, S

    2015-06-15

    Purpose: To measure the prompt gamma emission from the important elements found in tissue ({sup 16}O,{sup 12}C and {sup 14}N) in a clinical passive-scatter treatment environment. Methods: The targets (composed of water, Perspex, graphite and liquid nitrogen) were irradiated with a 200 MeV passive-scatter proton beam and the discrete prompt gamma energy spectra was detected by a high resolution 2′ × 2′ LaBr. detector. In order to reduce the high level of radiation produced by the beam line elements, the detector was surrounded by 10 cm of lead to attenuate the scattered gamma-rays entering the detector with an extra 5 cm thick layer of lead added along the beam direction. A 10 cm thick collimator with a 5 cm × 10 cm rectangular opening was also used. Results: The prompt gamma peaks at 6.13 MeV and 4.44 MeV were clearly identified as a Result of the inelastic nuclear reaction between the protons and the 16O atoms found in the water target. The 6.13 MeV peak was 5% higher than the peak at 4.44 MeV for the water target. The 4.44 MeV peak was the only identified emission in the prompt gamma energy spectra from the graphite target ({sup 12}C). The expected 2.313 MeV peak form the{sup 14}N (liquid nitrogen target) was identified, but the other expected {sup 14}N peaks could not be resolved. Conclusion: Prompt gamma measurements with a passive-scatter proton beam are possible, but the presence of a high amount of background radiation from the patient final collimator presents a challenge at the treatment isocenter. The prominent prompt gamma peaks at 6.13 MeV and 4.44 MeV were identified from the water, Perspex and graphite targets. The prompt gammas from the liquid nitrogen target were difficult to see, but may not be significant in the in-vivo verification process.

  6. Assimilation of High 18O/16O Crust by Shergottite-Nakhlite-Chassigny (SNC) Magmas on Mars

    NASA Astrophysics Data System (ADS)

    Day, J. M.; Taylor, L. A.; Valley, J. W.; Spicuzza, M. J.

    2005-12-01

    There is significant geochemical evidence for assimilation of crustal material into sub-aerial, mantle-derived, terrestrial basaltic magmas. Some of the most powerful constraints on crustal assimilation come from oxygen isotope studies, because supracrustal rocks often have distinct 18O/16O ratios resulting from interaction with Earth's hydrosphere. From a planetary perspective, studies of carbonate concretions from meteorite ALH84001 have yielded evidence for low-temperature crustal interaction at or near the surface of its putative parent body, Mars. This finding raises the possibility that crustal assimilation processes may be tracked using oxygen isotopes in combination with geochemical data of other reputed martian (SNC) meteorites. The whole-rock oxygen isotope ratios (Laser fluorination δ18O = +4.21 to +5.85‰ VSMOW) of SNC meteorites, correlate with aspects of their incompatible element chemistry. Some of the oxygen isotope variability may be explained by post-magmatic alteration on Mars or Earth; however, it appears, based on petrographic and geochemical observations, that a number of SNC meteorites, especially Shergottites, retain the original whole-rock oxygen isotope values of their magmas prior to crystallisation. Correlations between oxygen isotopes and incompatible element geochemistry are consistent with assimilation of a high-18O/16O, incompatible-element rich, oxidizing crustal component by hot, mantle-derived magmas (δ18O = ~~4.2‰). A crustal component has previously been recognized from Sr-Nd-Os isotope systematics and oxygen fugacity measurements of SNC meteorites. Oxygen isotope evidence from SNC meteorites suggests high-18O/16O crustal contaminants on Mars result from low temperature (< 300°C) interaction with martian hydrosphere. The extent of apparent crustal contamination tracked by oxygen isotopes in SNC meteorites implies that the majority of martian crust may have undergone such interactions. Evidence for assimilation of

  7. Zn location in the W-type hexagonal ferrite SrZnCoFe16O27.

    PubMed

    Graetsch, Heribert A

    2002-11-01

    The title compound, SrZnCoFe(16)O(27) (ZnCo-W), strontium zinc cobalt hexadecairon oxide, crystallizes in space group P6(3)/mmc, with the Sr atom at a site with -6 m 2 symmetry and Zn(2+) located at two tetrahedral sites (4e and 4f, each with 3m symmetry) of the spinel blocks. The Zn occupancy is 36% on equipoint 4e and 14% on 4f. The enrichment of diamagnetic ions on one of seven sublattices is thought to be responsible for the high temperature dependence of the saturation magnetization.

  8. Ab initio path integral simulation study on 16O/ 18O isotope effect in water and hydronium ion

    NASA Astrophysics Data System (ADS)

    Tachikawa, Masanori; Shiga, Motoyuki

    2005-05-01

    An ab initio path integral molecular dynamics simulation has been performed to study the 16O and 18O isotopomers for a water molecule and a hydronium ion at temperature 300 K. The average O-H bond length of H 218O molecule is slightly shorter than that of H 216O molecule, while that of H 318O + is slightly longer than that of H 316O +. For hydronium ions, the Walden inversion of H 318O +, as well as D 316O +, is found to be more restrained than that of H 316O +. The isotope effect in the electronic structure and thermochemical properties for these isotopomers are also shown.

  9. Detailed study and mean field interpretation of {sup 16}O+{sup 12}C elastic scattering at seven medium energies

    SciTech Connect

    Nicoli, M. P.; Haas, F.; Freeman, R. M.; Szilner, S.; Basrak, Z.; Morsad, A.; Satchler, G. R.; Brandan, M. E.

    2000-03-01

    Detailed measurements of the elastic scattering of {sup 16}O ions from {sup 12}C have been carried out at seven energies from 62 to 124 MeV, at center-of-mass angles from about 10 degree sign to about 145 degree sign . A coherent optical model analysis of these data has been performed using both the Woods-Saxon and the folding-model potentials. The extracted results are consistent with analyses of data at higher energies for this and similar light heavy-ion systems. Some model-independent spline forms for the real potentials were also investigated. (c) 2000 The American Physical Society.

  10. Relativistic calculations of induced polarization in 12C(e,e'p-->) reactions

    NASA Astrophysics Data System (ADS)

    Johansson, J. I.; Sherif, H. S.

    1999-06-01

    Relativistic calculations of the induced proton polarization in quasifree electron scattering on 12C are presented. Good agreement with the experimental data of Woo et al. is obtained. The relativistic calculations yield a somewhat better description of the data than the nonrelativistic ones. Differences between the two approaches are more pronounced at larger missing momenta suggesting further experimental work in this region.

  11. Laser-Shot-Induced Chemical Reactions inside Nanotubes: a TDDFT investigation

    NASA Astrophysics Data System (ADS)

    Zhang, Hong; Miyamoto, Yoshiyuki; Rubio, Angel

    2011-03-01

    We present the application of the time-dependent density functional theory (TDDFT) on ultrafast laser pulse which induces dynamics in molecules encapsulated by a nanotube. A strong laser pulse polarized perpendicular to the tube axis induces a giant bond-stretch of an HCl molecule inside both C and BN nanotubes. Depending on the initial orientation of the HCl molecule, the subsequent laser-induced dynamics is different. We also observed a radial motion of the nanotube and vacancies appear on the tube wall when the HCl is perpendicular to tube axis. Furthermore, the disintegration of HCl molecules took place when their molecular axis tilted to tube axis. These simulations are important to analyze light-induced nanochemistry and manipulation of nanostructures encapsulated in organic and inorganic nanotubes. The computational scheme used in present work was a combination of the molecular dynamics and real-time propagation of electron wave functions under presence of strong optical field [2,3]. The energy conservation rule was checked to monitor the numerical stability.

  12. Dissociation pathways of a single dimethyl disulfide on Cu(111): Reaction induced by simultaneous excitation of two vibrational modes

    SciTech Connect

    Motobayashi, Kenta; Kim, Yousoo; Arafune, Ryuichi; Ohara, Michiaki; Ueba, Hiromu; Kawai, Maki

    2014-05-21

    We present a novel reaction mechanism for a single adsorbed molecule that proceeds via simultaneous excitation of two different vibrational modes excited by inelastic tunneling electrons from a scanning tunneling microscope. Specifically, we analyze the dissociation of a single dimethyl disulfide (DMDS, (CH{sub 3}S){sub 2}) molecule on Cu(111) by using a versatile theoretical method, which permits us to simulate reaction rates as a function of sample bias voltage. The reaction is induced by the excitation of C-H stretch and S-S stretch modes by a two-electron process at low positive bias voltages. However, at increased voltages, the dissociation becomes a single-electron process that excites a combination mode of these stretches, where excitation of the C-H stretch is the energy source and excitation of the S-S stretch mode enhances the anharmonic coupling rate. A much smaller dissociation yield (few orders of magnitude) at negative bias voltages is understood in terms of the projected density of states of a single DMDS on Cu(111), which reflects resonant excitation through the molecular orbitals.

  13. Neutron-induced transmutation reactions in 237Np, 238Pu, and 239Pu at the massive natural uranium spallation target

    NASA Astrophysics Data System (ADS)

    Zavorka, L.; Adam, J.; Baldin, A. A.; Caloun, P.; Chilap, V. V.; Furman, W. I.; Kadykov, M. G.; Khushvaktov, J.; Pronskikh, V. S.; Solnyshkin, A. A.; Sotnikov, V.; Stegailov, V. I.; Suchopar, M.; Tsoupko-Sitnikov, V. M.; Tyutyunnikov, S. I.; Voronko, V.; Vrzalova, J.

    2015-04-01

    Transmutation reactions in the 237Np, 238Pu, and 239Pu samples were investigated in the neutron field generated inside a massive (m = 512 kg) natural uranium spallation target. The uranium target assembly QUINTA was irradiated with the deuteron beams of kinetic energy 2, 4, and 8 GeV provided by the Nuclotron accelerator at the Joint Institute for Nuclear Research (JINR) in Dubna. The neutron-induced transmutation of the actinide samples was measured off-line by implementing methods of gamma-ray spectrometry with HPGe detectors. Results of measurement are expressed in the form of both the individual reaction rates and average fission transmutation rates. For the purpose of validation of radiation transport programs, the experimental results were compared with simulations of neutron production and distribution performed by the MCNPX 2.7 and MARS15 codes employing the INCL4-ABLA physics models and LAQGSM event generator, respectively. In general, a good agreement between the experimental and calculated reaction rates was found in the whole interval of provided beam energies.

  14. Dissociation pathways of a single dimethyl disulfide on Cu(111): reaction induced by simultaneous excitation of two vibrational modes.

    PubMed

    Motobayashi, Kenta; Kim, Yousoo; Arafune, Ryuichi; Ohara, Michiaki; Ueba, Hiromu; Kawai, Maki

    2014-05-21

    We present a novel reaction mechanism for a single adsorbed molecule that proceeds via simultaneous excitation of two different vibrational modes excited by inelastic tunneling electrons from a scanning tunneling microscope. Specifically, we analyze the dissociation of a single dimethyl disulfide (DMDS, (CH3S)2) molecule on Cu(111) by using a versatile theoretical method, which permits us to simulate reaction rates as a function of sample bias voltage. The reaction is induced by the excitation of C-H stretch and S-S stretch modes by a two-electron process at low positive bias voltages. However, at increased voltages, the dissociation becomes a single-electron process that excites a combination mode of these stretches, where excitation of the C-H stretch is the energy source and excitation of the S-S stretch mode enhances the anharmonic coupling rate. A much smaller dissociation yield (few orders of magnitude) at negative bias voltages is understood in terms of the projected density of states of a single DMDS on Cu(111), which reflects resonant excitation through the molecular orbitals.

  15. Variations of boundary reaction rate and particle size on the diffusion-induced stress in a phase separating electrode

    SciTech Connect

    Zhang, Lei; He, Linghui; Ni, Yong; Song, Yicheng

    2014-10-14

    In contrast to the case of single-phase delithiation wherein faster discharging leads to higher diffusion-induced stress (DIS), this paper reports nonmonotonous dependency of the boundary reaction rate on the DIS in nanosized spherical electrode accompanying phase separation. It is attributed to a transition from two-phase to single-phase delithiation driven by increase of the boundary reaction rate leading to narrowing and vanishing of the miscibility gap in a range of the particle size. The profiles of lithium concentration and the DIS are identified during the transition based on a continuum model. The resultant maximum DIS first decreases in the region of two-phase delithiation and later returns to increase in the region of single-phase delithiation with the increase of the boundary reaction rate. A map for the failure behavior in the spherical electrode particle is constructed based on the Tresca failure criterion. These results indicate that the failure caused by the DIS can be avoided by appropriate selection of the said parameters in such electrodes.

  16. Magnetically sensitive light-induced reactions in cryptochrome are consistent with its proposed role as a magnetoreceptor.

    PubMed

    Maeda, Kiminori; Robinson, Alexander J; Henbest, Kevin B; Hogben, Hannah J; Biskup, Till; Ahmad, Margaret; Schleicher, Erik; Weber, Stefan; Timmel, Christiane R; Hore, P J

    2012-03-27

    Among the biological phenomena that fall within the emerging field of "quantum biology" is the suggestion that magnetically sensitive chemical reactions are responsible for the magnetic compass of migratory birds. It has been proposed that transient radical pairs are formed by photo-induced electron transfer reactions in cryptochrome proteins and that their coherent spin dynamics are influenced by the geomagnetic field leading to changes in the quantum yield of the signaling state of the protein. Despite a variety of supporting evidence, it is still not clear whether cryptochromes have the properties required to respond to magnetic interactions orders of magnitude weaker than the thermal energy, k(B)T. Here we demonstrate that the kinetics and quantum yields of photo-induced flavin-tryptophan radical pairs in cryptochrome are indeed magnetically sensitive. The mechanistic origin of the magnetic field effect is clarified, its dependence on the strength of the magnetic field measured, and the rates of relevant spin-dependent, spin-independent, and spin-decoherence processes determined. We argue that cryptochrome is fit for purpose as a chemical magnetoreceptor.

  17. Magnetically sensitive light-induced reactions in cryptochrome are consistent with its proposed role as a magnetoreceptor

    PubMed Central

    Maeda, Kiminori; Robinson, Alexander J.; Henbest, Kevin B.; Hogben, Hannah J.; Biskup, Till; Ahmad, Margaret; Schleicher, Erik; Weber, Stefan; Timmel, Christiane R.; Hore, P. J.

    2012-01-01

    Among the biological phenomena that fall within the emerging field of “quantum biology” is the suggestion that magnetically sensitive chemical reactions are responsible for the magnetic compass of migratory birds. It has been proposed that transient radical pairs are formed by photo-induced electron transfer reactions in cryptochrome proteins and that their coherent spin dynamics are influenced by the geomagnetic field leading to changes in the quantum yield of the signaling state of the protein. Despite a variety of supporting evidence, it is still not clear whether cryptochromes have the properties required to respond to magnetic interactions orders of magnitude weaker than the thermal energy, kBT. Here we demonstrate that the kinetics and quantum yields of photo-induced flavin—tryptophan radical pairs in cryptochrome are indeed magnetically sensitive. The mechanistic origin of the magnetic field effect is clarified, its dependence on the strength of the magnetic field measured, and the rates of relevant spin-dependent, spin-independent, and spin-decoherence processes determined. We argue that cryptochrome is fit for purpose as a chemical magnetoreceptor. PMID:22421133

  18. Mutation-induced perturbation of the special pair P840 in the homodimeric reaction center in green sulfur bacteria.

    PubMed

    Azai, Chihiro; Sano, Yuko; Kato, Yuki; Noguchi, Takumi; Oh-oka, Hirozo

    2016-01-25

    Homodimeric photosynthetic reaction centers (RCs) in green sulfur bacteria and heliobacteria are functional homologs of Photosystem (PS) I in oxygenic phototrophs. They show unique features in their electron transfer reactions; however, detailed structural information has not been available so far. We mutated PscA-Leu688 and PscA-Val689 to cysteine residues in the green sulfur bacterium Chlorobaculum tepidum; these residues were predicted to interact with the special pair P840, based on sequence comparison with PS I. Spectroelectrochemical measurements showed that the L688C and V689C mutations altered a near-infrared difference spectrum upon P840 oxidation, as well as the redox potential of P840. Light-induced Fourier transform infrared difference measurements showed that the L688C mutation induced a differential signal of the S-H stretching vibration in the P840(+)/P840 spectrum, as reported in P800(+)/P800 difference spectrum in a heliobacterial RC. Spectral changes in the 13(1)-keto C=O region, caused by both mutations, revealed corresponding changes in the electronic structure of P840 and in the hydrogen-bonding interaction at the 13(1)-keto C=O group. These results suggest that there is a common spatial configuration around the special pair sites among type 1 RCs. The data also provided evidence that P840 has a symmetric electronic structure, as expected from a homodimeric RC.

  19. Light-induced nitrous acid (HONO) production from NO2 heterogeneous reactions on household chemicals

    NASA Astrophysics Data System (ADS)

    Gómez Alvarez, Elena; Sörgel, Matthias; Gligorovski, Sasho; Bassil, Sabina; Bartolomei, Vincent; Coulomb, Bruno; Zetzsch, Cornelius; Wortham, Henri

    2014-10-01

    Nitrous acid (HONO) can be generated in various indoor environments directly during combustion processes or indirectly via heterogeneous NO2 reactions with water adsorbed layers on diverse surfaces. Indoors not only the concentrations of NO2 are higher but the surface to volume (S/V) ratios are larger and therefore the potential of HONO production is significantly elevated compared to outdoors. It has been claimed that the UV solar light is largely attenuated indoors. Here, we show that solar light (λ > 340 nm) penetrates indoors and can influence the heterogeneous reactions of gas-phase NO2 with various household surfaces. The NO2 to HONO conversion mediated by light on surfaces covered with domestic chemicals has been determined at atmospherically relevant conditions i.e. 50 ppb NO2 and 50% RH. The formation rates of HONO were enhanced in presence of light for all the studied surfaces and are determined in the following order: 1.3·109 molecules cm-2 s-1 for borosilicate glass, 1.7·109 molecules cm-2 s-1 for bathroom cleaner, 1.0·1010 molecules cm-2 s-1 on alkaline detergent (floor cleaner), 1.3·1010 molecules cm-2 s-1 for white wall paint and 2.7·1010 molecules cm-2 s-1 for lacquer. These results highlight the potential of household chemicals, used for cleaning purposes to generate HONO indoors through light-enhanced NO2 heterogeneous reactions. The results obtained have been applied to predict the timely evolution of HONO in a real indoor environment using a dynamic mass balance model. A steady state mixing ratio of HONO has been estimated at 1.6 ppb assuming a contribution from glass, paint and lacquer and considering the photolysis of HONO as the most important loss process.

  20. Experimental cross-sections for proton-induced nuclear reactions on natMo

    NASA Astrophysics Data System (ADS)

    Červenák, Jaroslav; Lebeda, Ondřej

    2016-08-01

    In the framework of the Co-ordinated Research Project of the IAEA, we measured in detail cross-sections of the nuclear reactions natMo(p,x)93gTc, 93mTc, 93m+gTc, 94gTc, 94mTc, 95gTc, 95mTc, 96m+gTc, 97mTc, 99mTc, 90Mo, 93mMo, 99Mo, 88gNb, 88mNb, 89gNb, 89mNb, 90m+gNb, 90m+gNbcum, 91mNb, 92mNb, 95gNb, 95mNb, 95m+gNb, 96Nb, 97m+gNb, 88m+gZrcum and 89m+gZrcum in the energy range of 6.9-35.8 MeV. The data for formation of 97mTc, 88gNb, 88mNb and 89mNb are reported for the first time. The obtained results were compared to the prediction of the nuclear reaction model code TALYS adopted from the TENDL-2015 library and to the previously published cross-sections. The thick target yields for all the radionuclides were calculated from the measured data. We suggest recommended cross-sections and thick target yields for the 100Mo(p,2n)99mTc, 100Mo(p,x)99Mo and natMo(p,x)96m+gTc nuclear reactions deduced from the selected experimental data.