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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. Light particle emission in 16O-induced reactions at 140, 215, and 310 MeV

    NASA Astrophysics Data System (ADS)

    Awes, T. C.; Saini, S.; Poggi, G.; Gelbke, C. K.; Cha, D.; Legrain, R.; Westfall, G. D.

    1982-05-01

    Double differential cross sections have been measured for energetic p, d, t, and α particles emitted in 16O-induced reactions on targets of A1, Zr, and Au at incident energies of 140, 215, and 310 MeV. The energy and angular distributions are well described by isotropic emission from a moving thermal source. The extracted temperature and velocity parameters are found to vary systematically with the incident energy per nucleon above the Coulomb barrier. The observed trends cannot be explained by compound nucleus emission but instead suggest emission from a source which consists of comparable contributions from target and projectile. Alternatively, the proton energy spectra are compared with a precompound model and with a simple knockout model. The d, t, and α-particle cross sections are also described in terms of a generalized coalescence relation which takes into account Coulomb repulsion from the target nucleus. NUCLEAR REACTIONS 27Al(16O,x), E=140, 215, and 310 MeV; 90Zr(16O,x), E=215 and 310 MeV; 197Au(16O,x), E=140, 215, and 310 MeV; x=p, d, t, and α. Measured σ(Ex,θx). Analysis in terms of moving source, precompound, knockout, and coalescence models.

  3. Quantum stereodynamics of the 18O +16O16O16O18O +16O exchange reaction at low collision energy

    NASA Astrophysics Data System (ADS)

    Privat, Erwan; Guillon, Grégoire; Honvault, Pascal

    2017-10-01

    We present a quantum study of stereodynamics of the 18O +16O16O (v = 0, j = 1) →16O18O (v‧ = 0,j‧) +16O exchange reaction at a collision energy Ecoll = 0.01eV . Polarization moments of the reactants have been computed and stereodynamical portraits have been generated. The results show that the reactant preferred relative orientations are strongly dependent on the scattering angle and on the product rotational states.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. New Astrophysical Reaction Rate for the 12C(α, γ)16O Reaction

    NASA Astrophysics Data System (ADS)

    An, Zhen-Dong; Ma, Yu-Gang; Fan, Gong-Tao; Li, Yong-Jiang; Chen, Zhen-Peng; Sun, Ye-Ying

    2016-01-01

    A new astrophysical reaction rate for 12C(α, γ)16O has been evaluated on the basis of a global R-matrix fitting to the available experimental data. The reaction rates of 12C(α, γ)16O for stellar temperatures between 0.04 ≤ T9 ≤ 10 are provided in a tabular form and by an analytical fitting expression. At T9 = 0.2, the reaction rate is (7.83 ± 0.35) × 1015 cm3 mol-1 s-1, where stellar helium burning occurs.

  9. Short-range and tensor correlations in the 16O(e,e'pn) reaction

    NASA Astrophysics Data System (ADS)

    Giusti, C.; Müther, H.; Pacati, F. D.; Stauf, M.

    1999-11-01

    The cross sections for electron-induced two-nucleon knockout reactions are evaluated for the example of the 16O(e,e'pn)14N reaction leading to discrete states in the residual nucleus 14N. These calculations account for the effects of nucleon-nucleon correlations and include the contributions of two-body meson exchange currents as the pion seagull, pion in flight, and the isobar current contribution. The effects of short-range as well as tensor correlations are calculated within the framework of the coupled cluster method employing the Argonne V14 potential as a model for a realistic nucleon-nucleon interaction. The relative importance of correlation effects as compared to the contribution of the meson exchange currents depends on the final state of the residual nucleus. The cross section leading to specific states, such as, e.g., the ground state of 14N, is rather sensitive to the details of the correlated wave function.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Evidence of tensor interactions in 16O observed via (p,d) reaction

    NASA Astrophysics Data System (ADS)

    Ong, H. J.; Tanihata, I.; Tamii, A.; Myo, T.; Ogata, K.; Fukuda, M.; Hirota, K.; Ikeda, K.; Ishikawa, D.; Kawabata, T.; Matsubara, H.; Matsuta, K.; Mihara, M.; Naito, T.; Nishimura, D.; Ogawa, Y.; Okamura, H.; Ozawa, A.; Pang, D. Y.; Sakaguchi, H.; Sekiguchi, K.; Suzuki, T.; Taniguchi, M.; Takashina, M.; Toki, H.; Yasuda, Y.; Yosoi, M.; Zenihiro, J.

    2014-03-01

    We measured the differential cross sections of the 16O(p,d) reaction populating the ground state and several low-lying excited states in 15O using 198-, 295- and 392-MeV proton beams at the Research Center for Nuclear Physics (RCNP), Osaka University, to study the effect of the tensor interactions in 16O. Dividing the cross sections for each excited state by the one for the ground state and comparing the ratios over a wide range of momentum transfer, we found a marked enhancement of the ratio for the positive-parity state(s). The observation is consistent with large components of high-momentum neutrons in the ground-state configurations of 16O due possibly to the tensor interactions.

  16. Effect of tensor interactions in 16O studied via (p,d) reaction

    NASA Astrophysics Data System (ADS)

    Ong, H. J.; Tanihata, I.; Tamii, A.; Myo, T.; Ogata, K.; Fukuda, M.; Hirota, K.; Ikeda, K.; Ishikawa, D.; Kawabata, T.; Matsubara, H.; Matsuta, K.; Mihara, M.; Naito, T.; Nishimura, D.; Ogawa, Y.; Ozawa, A.; Pang, D. Y.; Sakaguchi, H.; Sekiguchi, K.; Suzuki, T.; Taniguchi, M.; Takashina, M.; Toki, H.; Yasuda, Y.; Yosoi, M.; Zenihiro, J.

    2014-12-01

    The differential cross sections of the 16O(p,d) reaction populating the ground state and several low-lying excited states in 15O were measured using 198-, 295- and 392-MeV proton beams at the Research Center for Nuclear Physics (RCNP), Osaka University, to study the effect of the tensor interactions in 16O. Dividing the cross sections for each excited state by the one for the ground state and comparing the ratios over a wide range of momentum transfer, we found a marked enhancement of the ratio for the positive-parity state(s). The observation is consistent with large components of high-momentum neutrons in the ground-state configurations of 16O due possibly to the tensor interactions.

  17. 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.

  18. Calculation of photo-nuclear reaction cross sections for 16O

    NASA Astrophysics Data System (ADS)

    Arasoglu, Ali; Faruk Ozdemir, Omer

    2015-07-01

    Because of the high thermal expansion coefficient of uranium, the fuel used in nuclear power plants is usually in the form of UO2 which has ceramic structure and small thermal expansion coefficient. UO2 include one uranium atom and two oxygen atoms. After fission progress, total energy values of emitted gamma are about 14 MeV. This gamma energy may cause transmutation of 16O isotopes. Transmutation of 16O isotopes changes physical properties of nuclear fuel. Due to above explanations, it is very important to calculate photo-nuclear reaction cross sections of 16O. In this study; for (γ,p), (γ,np), (γ,n) and (γ,2n) reactions of 16O, photo-nuclear reaction cross-sections were calculated using different models for pre-equilibrium and equilibrium effects. Taking incident gamma energy values up to 40 MeV, Hybrid and Cascade Exciton Models were used for pre-equilibrium calculations and Weisskopf-Ewing (Equilibrium) Model was used for equilibrium model calculations. Calculation results were compared with experimental and theoretical data. While experimental results were obtained from EXFOR, TENDL-2013, JENDL/PD-2004 and ENDF/B VII.1 data base were used to get theoretical results.

  19. The ^12C(^6Li,d)^16O reaction at 34 MeV

    NASA Astrophysics Data System (ADS)

    Mendez, A. J.; Brune, C. R.; Karwowski, H. J.; Ludwig, E. J.; Veal, K. D.; Bartosz, E. E.; Cathers, P. D.; Drummer, T. L.; Kemper, K. W.; Koslowska, B.

    1996-05-01

    Present models of the ^6Li nucleus are in disagreement(D. R. Lehman, Colloque de Physique suppl. n22, 52), C6-47 (1990).^,(A. M. Eiro et al.), Few Body Systems suppl. 99 (1995). as to the sign of the D- to S-state ratio, η. Transfer reactions induced by polarized ^6Li have been predicted^3 to be sensitive to η, and recent measurements(A. J. Mendez et al.), Phys. Rev. C 51, 651 (1995). have shown a sensitivity to the presence of the D-state in ^6Li. We will present cross-section, A_y, and A_zz angular-distribution measurements for the ^12C(^6Li,d)^16O reaction at 34 MeV over the laboratory angular range 6.5^circ - 60^circ. We find Ay to be large, negative and highly oscillatory for the 0^+ ground state and predominantly negative, but smaller and less oscillatory, for both the 3^- state at 6.13 MeV and the 2^+, 1^- doublet at 7 MeV. The A_zz distributions for the first two states are large and oscillatory about zero, while that of the doublet is predominantly negative. We will present a DWBA analysis of the data and discuss the consequences for η(^6Li).

  20. 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.

  1. 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.

  2. Effect of Tensor Interactions in 16O Studied via (p,d) Reaction

    NASA Astrophysics Data System (ADS)

    Ong, H. J.; Tanihata, I.; Tamii, A.; Myo, T.; Ogata, K.; Fukuda, M.; Hirota, K.; Ikeda, K.; Ishikawa, D.; Kawabata, T.; Matsubara, H.; Matsuta, K.; Mihara, M.; Naito, T.; Nishimura, D.; Ogawa, Y.; Ozawa, A.; Pang, D. Y.; Sakaguchi, H.; Sekiguchi, K.; Suzuki, T.; Taniguchi, M.; Takashina, M.; Toki, H.; Yasuda, Y.; Yosoi, M.; Zenihiro, J.

    We report a study on the effect of the tensor interactions in 16O via the (p,d) reaction using proton beams at 198, 295, and 392 MeV at the Research Center for Nuclear Physics (RCNP), Osaka University. Differential cross sections populating the ground state and several low-lying excited states in 15O were measured. Dividing the cross sections for each excited state by the one for the ground state and comparing the ratios over a wide range of momentum transfer, we found a marked enhancement of the ratio for the 5/2+ and/or 1/2+ state(s). The observation indicates large components of high-momentum neutrons in the ground-state configurations of 16O due possibly to the tensor interactions.

  3. 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.

  4. Study of nuclear fusion-fission dynamics in 16O+194Pt reaction

    NASA Astrophysics Data System (ADS)

    Kapoor, K.; Verma, S.; Sharma, P.; Mahajan, R.; Kaur, N.; Kaur, G.; Behera, B. R.; Singh, K. P.; Singh, H.; Dubey, R.; Saneesh, N.; Jhingan, A.; Sugathan, P.; Mohanto, G.; Nayak, B. K.; Saxena, A.; Sharma, H. P.; Chamoli, S. K.; Mukul, I.; Kumar, A.

    2017-06-01

    Pre- and post-scission α-particle multiplicities have been measured for the reaction 16O + 194Pt at 98.4 MeV forming compound nucleus 210Rn. The α-particle's yield has been measured in coincidence with the fission fragments at various angles. The moving source analysis was performed to extract the alpha particle multiplicity which yielded the contribution of pre- and post- scission components. The pre-scission α-particle multiplicity has been compared with JOANNE2 statistical model code predictions to extract fission time scale and which is observed to be around 55zs (1zs=10-21s).

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Role of rotational energy component in the dynamics of 16O+198Pt reaction

    NASA Astrophysics Data System (ADS)

    Sharma, Manoj K.; Rajni; Jain, Deepika

    2017-09-01

    The role of rotational energy is investigated in reference to the dynamics of 16O+198Pt →214Rn∗ reaction using the sticking (IS) and the non-sticking (INS) limits of moment of inertia within the framework of dynamical cluster decay model. The decay barrier height and barrier position get significantly modified for the use of sticking or non-sticking choice, which in turn reproduce the evaporation residue and the fusion-fission cross-sections nicely by the IS approach, while the INS approach provides feasible addressal of data only for evaporation residue channel. Moreover, the fragmentation path of decaying fragments of 214Rn∗ compound nucleus gets influenced for different choices of moment of inertia. Beside this, the role of nuclear deformations i.e. static, dynamic quadurpole (β2) and higher order static deformation up to β4 are duly investigated for both choices of the moment of inertia.

  10. 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.

  11. The 12C(α ,γ )16O reaction and its implications for stellar helium burning

    NASA Astrophysics Data System (ADS)

    deBoer, R. J.; Görres, J.; Wiescher, M.; Azuma, R. E.; Best, A.; Brune, C. R.; Fields, C. E.; Jones, S.; Pignatari, M.; Sayre, D.; Smith, K.; Timmes, F. X.; Uberseder, E.

    2017-07-01

    The creation of carbon and oxygen in our Universe is one of the forefront questions in nuclear astrophysics. The determination of the abundance of these elements is key to our understanding of both the formation of life on Earth and to the life cycles of stars. While nearly all models of different nucleosynthesis environments are affected by the production of carbon and oxygen, a key ingredient, the precise determination of the reaction rate of 12C(α ,γ )16O, has long remained elusive. This is owed to the reaction's inaccessibility, both experimentally and theoretically. Nuclear theory has struggled to calculate this reaction rate because the cross section is produced through different underlying nuclear mechanisms. Isospin selection rules suppress the E 1 component of the ground state cross section, creating a unique situation where the E 1 and E 2 contributions are of nearly equal amplitudes. Experimentally there have also been great challenges. Measurements have been pushed to the limits of state-of-the-art techniques, often developed for just these measurements. The data have been plagued by uncharacterized uncertainties, often the result of the novel measurement techniques that have made the different results challenging to reconcile. However, the situation has markedly improved in recent years, and the desired level of uncertainty ≈10 % may be in sight. In this review the current understanding of this critical reaction is summarized. The emphasis is placed primarily on the experimental work and interpretation of the reaction data, but discussions of the theory and astrophysics are also pursued. The main goal is to summarize and clarify the current understanding of the reaction and then point the way forward to an improved determination of the reaction rate.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. Experimental investigations of the sub-Coulomb 12C+12C and 12C+16O reactions

    NASA Astrophysics Data System (ADS)

    Courtin, S.; Fruet, G.; Jenkins, D. G.; Jiang, C. L.; Heine, M.; Montanari, D.; Santiago-Gonzalez, D.; Avila-Coronado, M.; Morris, L. G.; Goasduff, A.; Rehm, E.; Back, B.; Bourgin, D.; Beck, C.

    2017-06-01

    Cluster resonances in light heavy-ion systems like 12C+12C and 12C+16O may have a major impact on astrophysics stellar scenarios. Resonant radiative capture reactions have been studied for these systems at energies at and slightly below their Coulomb barriers to investigate the possible 12C-12C and 12C-16O molecular origin of the resonances. Spins have been attributed to the resonances and specificities of their γ-decay have been identified. At deep sub-barrier energies, a fusion cross section measurement using the particle-γ coincidence technique is discussed for the 12C+12C system. A new project is presented to possibly extend the 12C+12C S low-energy S factor study.

  1. {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)

  2. Use of the 16O(d, α 0) 14N nuclear reaction in the analysis of oxide films

    NASA Astrophysics Data System (ADS)

    Simpson, J. C. B.; Groves, J. M. C.; Earwaker, L. G.

    1985-06-01

    The use of the 16O(d, α 0) 14N nuclear reaction to obtain oxygen concentration profiles in surface oxide layers, up to 4000 Å thick, has been studied using incident deuterons of 900 keV and 1.08 MeV and comparisons made of the oxygen sensitivities and depth resolutions. Samples investigated include a Ta 2O 5 on tantalum standard, thermally grown silicon oxide films on silicon and two types of chromium conversion coatings on zinc electroplated panels. A nuclear reaction simulation code has been employed to reveal surface compositions from the energy spectra of the emitted alpha particles.

  3. 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.

  4. 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.

  5. Asymptotic Normalization Coefficients from the {sup 15}N({sup 3}He,d){sup 16}O Reaction and the Astrophysical Factor for the {sup 15}N(p,{gamma}){sup 16}O Capture

    SciTech Connect

    Burjan, V.; Bem, P.; Hons, Z.; Kroha, V.; Mrazek, J.; Novak, J.; Piskor, S.; Simeckova, E.; Vincour, J.; Cherubini, S.; La Cognata, M.; Pizzone, R. G.; Romano, S.; Spitaleri, C.; Tumino, A.; Gagliardi, C. A.; Mukhamedzhanov, A. M.; Plunkett, A.; Trache, L.; Tribble, R. E.

    2008-05-12

    The angular distributions of the {sup 15}N({sup 3}He,d){sup 16}O reaction were measured with the aim to determine the direct capture rate of the astrophysical reaction {sup 15}N(p, {gamma}){sup 16}O by deducing asymptotic normalization coefficients (ANC). The {sup 15}N(p,{gamma}){sup 16}O reaction is a part of the CNO cycle having importance in the nucleosynthesis of the N and O isotopes. The measurement was carried out on the cyclotron U120M of NPI CAS at the energy 25.74 MeV of {sup 3}He ions in a gas chamber containing the high purity {sup 15}N isotope. The preliminary results of corresponding spectroscopic factors and ANC's were used for the estimation of the S-factor for the direct capture {sup 15}N(p,{gamma}){sup 16}O. Using the widths of the resonances E{sub R} = 312 and 962 keV, the total S-factor was determined within the framework of the R-matrix approach.

  6. New Improved Indirect Measurement of the 19F(p, α)16O Reaction at Energies of Astrophysical Relevance

    NASA Astrophysics Data System (ADS)

    Indelicato, I.; La Cognata, M.; Spitaleri, C.; Burjan, V.; Cherubini, S.; Gulino, M.; Hayakawa, S.; Hons, Z.; Kroha, V.; Lamia, L.; Mazzocco, M.; Mrazek, J.; Pizzone, R. G.; Romano, S.; Strano, E.; Torresi, D.; Tumino, A.

    2017-08-01

    Fluorine abundance determination is of great importance in stellar physics to understand s-elements production and mixing processes in asymptotic giant branch (AGB) stars. Up to now, theoretical models overproduce F abundances in AGB stars with respect to the observed values, thus calling for further investigation of the reactions involving fluorine. In particular, the 19F(p, α)16O reaction is the main destruction channel of fluorine at the bottom of the convective envelope in AGB stars, an H-rich environment where it can experience temperatures high enough to determine its destruction, owing to additional mixing processes. In this paper the Trojan horse method (THM) was used to extract the 19F(p, α 0)16O S-factor in the energy range of astrophysical interest (E cm ≈ 0-1 MeV). This is the most relevant channel at the low temperatures (few 107 K) characterizing the bottom of the convective envelope, according to current knowledge. A previous indirect experiment using the THM has observed three resonances in the energy regions below E cm ≈ 450 keV. These energies correspond to typical AGB temperatures, thus implying a significant increase in the reaction rate. Statistics are scarce for performing an accurate separation between resonances, preventing one from drawing a quantitative conclusion about their total widths and spin parities. Before THM measurement, only extrapolations were available below about 500 keV, showing a non-resonant behavior that sharply contradicts the trend of the astrophysical factor at higher energies. A new experiment has been performed to verify the measured TH astrophysical factor and to perform more accurate spectroscopy of the involved resonances.

  7. An Investigation of 4He+12C and 4He+16O Reactions Using the Cluster Model

    NASA Astrophysics Data System (ADS)

    A. H., Al-Ghamdi; Awad, A. Ibraheem; M. El-Azab, Farid

    2012-07-01

    The α-target semimicroscopic single folding potentials have been derived by folding a composite (repulsive and attractive) effective α-α interaction with the α-cluster distribution density in the target nuclei. The obtained potentials are considered as the real part of the nuclear optical model potentials, while the imaginary parts are phenomenologicaly expressed using the Woods—Saxon form. Nine sets of measured experimental data of the 4He+12C and 4He+16O elastic rainbow scattering over the energy range 80-240 MeV are analyzed using the obtained potentials. The data are successfully reproduced using the extracted potentials. The resulted reaction cross sections are also investigated and compared with the available corresponding data.

  8. RCNP E398 {sup 16}O,{sup 12}C(p,p’) experiment: Measurement of the γ-ray emission probability from giant resonances in relation to {sup 16}O,{sup 12}C(ν,ν’) reactions

    SciTech Connect

    Ou, I.; Yamada, Y.; Mori, T.; Yano, T.; Sakuda, M.; Tamii, A.; Suzuki, T.; Yosoi, M.; Aoi, N.; Ideguchi, E.; Hashimoto, T.; Miki, K.; Ito, T.; Iwamoto, C.; Yamamoto, T.; Akimune, H.

    2015-05-15

    We propose to measure the γ-ray emission probability from excited states above 5 MeV including giant resonance of {sup 16}O and {sup 12}C as a function of excitation energy in 1-MeV step. Here, we measure both the excitation energy (E{sub x}=5-30MeV) at the forward scattering angles (0°-3°) of the {sup 16}O, {sup 12}C (p, p’) reaction using Grand-Raiden Spectrometer and the energy of γ-rays (E{sub γ}) using an array of NaI(Tl) counters. The purpose of the experiment is to provide the basic and important information not only for the γ-ray production from primary neutral-current neutrino-oxygen (-carbon) interactions but also for that from the secondary hadronic (neutron-oxygen and -carbon) interactions.

  9. New study of the astrophysical reaction 13C(a,n)16O via the 13C(7Li,t)17O transfer reaction

    NASA Astrophysics Data System (ADS)

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

    PoS(NIC-IX)161 , , [1] , L. Gaudefroy[2] , J. Kiener[3] , A. Lefebvre-Schuhl[3] , M. Stanoiu[4] , V. The cross section of the 13 C(α,n)16 O reaction is a key ingredient for the comprehension of the s-process (slow neutron captures) in stars. This reaction is considered as the main neutron source for the s-process in low-mass Asymptotic Giant Branch (AGB) stars (1-3 solar mass) [1, 2, 3]. At the α-13 C energies of astrophysical interest (Ecm around 190 keV, corresponding to a tem- perature of 108 K) the contribution of the 17 O α-decay subthreshold resonance at 6.356 MeV to the 13 C(α,n)16 O cross section should be taken into account. The effect of this resonance is controversial after the different analyses of the Kubono et al. measurement [4] of the 6.356 MeV α-spectroscopic factor (Sα ) via the transfer reaction 13 C(6 Li,d)17 O . In order to further investigate the contribution of the 6.356 MeV resonance to the 13 C(α,n)16 O cross section, we performed a new measurement of its Sα factor via a different α-transfer reac- tion, namely the 13 C(7 Li,t)17 O reaction. The experiment was performed at the Orsay Tandem by using a 7 Li beam of 28 and 34 MeV on a 13C target. The angular distribution for the transfer dif- ferential cross section was measured by detecting the tritons at the focal plane of the SPLITPOLE spectrometer. The analysis procedure used in order to extract the yield of the 6.356 MeV level will be described. Preliminary results of the angular distribution will be shown.

  10. 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.

  11. New astrophysical S factor for the {sup 15}N(p,{gamma}){sup 16}O reaction via the asymptotic normalization coefficient (ANC) method

    SciTech Connect

    Mukhamedzhanov, A. M.; Gagliardi, C. A.; Goldberg, V. Z.; Plunkett, A.; Trache, L.; Tribble, R. E.; Bem, P.; Burjan, V.; Hons, Z.; Kroha, V.; Mrazek, J.; Novak, J.; Piskor, S.; Simeckova, E.; Vesely, F.; Vincour, J.; La Cognata, M.; Pizzone, R. G.; Romano, S.; Spitaleri, C.

    2008-07-15

    The {sup 15}N(p,{gamma}){sup 16}O reaction provides a path from the CN cycle to the CNO bi-cycle and CNO tri-cycle. The measured astrophysical factor for this reaction is dominated by resonant capture through two strong J{sup {pi}}=1{sup -} resonances at E{sub R}=312 and 962 keV and direct capture to the ground state. Asymptotic normalization coefficients (ANCs) for the ground and seven excited states in {sup 16}O were extracted from the comparison of experimental differential cross sections for the {sup 15}N({sup 3}He,d){sup 16}O reaction with distorted-wave Born approximation calculations. Using these ANCs and proton and {alpha} resonance widths determined from an R-matrix fit to the data from the {sup 15}N(p,{alpha}){sup 12}C reaction, we carried out an R-matrix calculation to obtain the astrophysical factor for the {sup 15}N(p,{gamma}){sup 16}O reaction. The results indicate that the direct capture contribution was previously overestimated. We find the astrophysical factor to be S(0)=36.0{+-}6.0 keV b, which is about a factor of 2 lower than the presently accepted value. We conclude that for every 2200{+-}300 cycles of the main CN cycle one CN catalyst is lost due to this reaction.

  12. Effects of triple-α and 12C(α, γ)16O reaction rates on the supernova nucleosynthesis in a massive star of 25 Mʘ

    NASA Astrophysics Data System (ADS)

    Kikuchi, Yukihiro; Hashimoto, Masa-aki; Ono, Masaomi; Fukuda, Ryohei

    2015-06-01

    We investigate the effects of triple-α and ^{12}{C}(α ,γ )^{16}O reaction rates on the production of supernova yields for a massive star of 25 M_{⊙}. We combine the reaction rates to examine the rate dependence, where the rates are considered to cover the possible variation of the rates based on experiments on the earth and on theory. We adopt four combinations of the reaction rates from two triple-α reaction rates and two ^{12}C(α ,γ )^{16}O ones. First, we examine the evolution of massive stars of 20 M_{⊙} and 25 M_{⊙} whose helium cores correspond to helium stars of 6 M_{⊙} and 8 M_{⊙}, respectively. While the 25 M_{⊙} stars evolve to the presupernova stages for all combinations of the reaction rates, the evolutionary paths of the 20 M_{⊙} stars proceed significantly differently for some combinations, which are unacceptable for progenitors of supernovae. Second, we perform calculations of supernova explosions within the limitation of spherical symmetry and compare the calculated abundance ratios with solar system abundances. We can deduce some constraints to the reaction rates. The results show that a conventional rate is adequate for a triple-α reaction rate and a rather higher value of the reaction rate within the upper limit for the experimental uncertainties is favorable for a ^{12}{C}(α ,γ )^{16}O rate.

  13. High resolution measurement of the 16O(γ,pn)14N0,1,2,... reaction

    NASA Astrophysics Data System (ADS)

    Garrow, K. R.; Adimi, F.; Kolb, N. R.; Lu, J.; Pywell, R. E.; Skopik, D. M.; Vogt, J. M.; Jury, J. W.; Kuzin, A.; Thompson, M. N.; Ryckebusch, J.

    2001-12-01

    The exclusive 16O(γ,pn)14N0,1,2,... reaction was measured for the photon energy range Eγ=98.5 to 141.0 MeV with an excitation energy resolution of 2.8 MeV. Protons were detected at 76° and 82° and coincident neutrons were detected at the opening angle for quasifree deuteron photodisintegration. Only the T=0, 1+, 3.95 MeV state in the residual 14N nucleus was significantly populated. This corresponds to a preferred L=0 angular momentum transfer to the recoil nucleus as is expected for quasifree kinematics. The absence of significant population to other discrete states is evidence that absorption on correlated proton-neutron pairs with an angular momentum transfer of L>=2 is largely suppressed for the low recoil momentum range of the current measurement. As a consequence of this fact, and the absence of unnatural parity states, only absorption on proton-neutron pairs in relative motion l=0,2 is expected for all possible shell model couplings. No significant population of the T=1 state at 2.31 MeV is consistent with previous measurements, demonstrating that absorption on proton-neutron pairs in an isospin triplet is suppressed. The results of the measurement to discrete states in the residual 14N nucleus are compared to microscopic calculations which include contributions above that of the mean field due to the short range and tensor parts of the nuclear potential. Clear separation in the contribution of (1p)-2 and (1p)-1(1s)-1 proton-neutron pairs is seen to occur at an excitation energy of 20+/-2 MeV. Significant population of the (1p)-1(1s)-1 continuum above 20 MeV indicates that absorption on L=1 nucleon pairs is also important near quasifree kinematics.

  14. Comment on "Cross section of the 13C(α ,n )16O reaction: A background for the measurement of geo-neutrinos"

    NASA Astrophysics Data System (ADS)

    Peters, W. A.

    2017-08-01

    Harissopulos et al. [Phys. Rev. C 72, 062801(R) (2005), 10.1103/PhysRevC.72.062801] report a cross section from a measurement that used a moderated neutron detector not capable of measuring the neutron energy and therefore unable to determine the relative contribution from neutrons that populate the ground state or excited 16O states in 13C(α ,n )16O reactions above 5 MeV. Since the energies of ejected neutrons populating the excited states are 6 MeV lower than those populating the ground state, the corresponding efficiency of their neutron detector for these neutrons was a factor of 2 higher than assumed. Therefore, the reported 13C(α ,n )16O cross sections above 5 MeV may be overcalculated by nearly 50%.

  15. 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.

  16. 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).

  17. 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.

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

    SciTech Connect

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

    2014-05-09

    The {sup 13}C(α,n){sup 16}O 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 {sup 13}C(α,n){sup 16}O 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 {sup 13}C pocket, thus putting the s-process in stars on safe physical ground. These inputs allow us to reproduce satisfactorily the solar distribution of elements.

  19. 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.

  20. 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.

  1. 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.

  2. THE FLUORINE DESTRUCTION IN STARS: FIRST EXPERIMENTAL STUDY OF THE {sup 19}F(p, {alpha}{sub 0}){sup 16}O REACTION AT ASTROPHYSICAL ENERGIES

    SciTech Connect

    La Cognata, M.; Spitaleri, C.; Indelicato, I.; Cherubini, S.; Gulino, M.; Kiss, G. G.; Lamia, L.; Pizzone, R. G.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Mukhamedzhanov, A. M.; Aliotta, M.; Burjan, V.; Hons, Z.; Kroha, V.; Mrazek, J.; Piskor, S.; Coc, A.

    2011-10-01

    The {sup 19}F(p, {alpha}){sup 16}O reaction is an important fluorine destruction channel in the proton-rich outer layers of asymptotic giant branch (AGB) stars and it might also play a role in hydrogen-deficient post-AGB star nucleosynthesis. So far, available direct measurements do not reach the energy region of astrophysical interest (E {sub cm} {approx}< 300 keV), because of the hindrance effect of the Coulomb barrier. The Trojan Horse (TH) method was thus used to access this energy region, by extracting the quasi-free contribution to the {sup 2}H({sup 19}F, {alpha}{sup 16}O)n and the {sup 19}F({sup 3}He, {alpha}{sup 16}O)d reactions. The TH measurement of the {alpha}{sub 0} channel shows the presence of resonant structures not observed before, which cause an increase of the reaction rate at astrophysical temperatures up to a factor of 1.7, with potential consequences for stellar nucleosynthesis.

  3. 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.

  4. New reaction rate for {sup 16}O(p,{gamma}){sup 17}F and its influence on the oxygen isotopic ratios in massive AGB stars

    SciTech Connect

    Iliadis, C.; Angulo, C.; Descouvemont, P.; Lugaro, M.; Mohr, P.

    2008-04-15

    The {sup 16}O(p,{gamma}){sup 17}F reaction rate is revisited with special emphasis on the stellar temperature range of T=60-100 MK, important for hot bottom burning in asymptotic giant branch (AGB) stars. We evaluate existing cross-section data that were obtained since 1958 and, if appropriate, correct published data for systematic errors that were not noticed previously, including the effects of coincidence summing and updated effective stopping powers. The data are interpreted by using two different models of nuclear reactions, that is, a potential model and R-matrix theory. A new astrophysical S factor and recommended thermonuclear reaction rates are presented. As a result of our work, the {sup 16}O(p,{gamma}){sup 17}F reaction has now the most precisely known rate involving any target nucleus in the mass A{>=}12 range, with reaction rate errors of about 7% over the entire temperature region of astrophysical interest (T=0.01-2.5 GK). The impact of the present improved reaction rate with its significantly reduced uncertainties on the hot bottom burning in AGB stars is discussed. In contrast to earlier results we find now that there is not clear evidence to date for any stellar grain origin from massive AGB stars.

  5. 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.

  6. 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.

  7. A supersonic jet target for the cross section measurement of the 12C(α, γ)16O reaction with the recoil mass separator ERNA

    NASA Astrophysics Data System (ADS)

    Rapagnani, D.; Buompane, R.; Di Leva, A.; Gialanella, L.; Busso, M.; De Cesare, M.; De Stefano, G.; Duarte, J. G.; Gasques, L. R.; Morales Gallegos, L.; Palmerini, S.; Romoli, M.; Tufariello, F.

    2017-09-01

    12C(α, γ)16O cross section plays a key-role in the stellar evolution and nucleosynthesis of massive stars. Hence, it must be determined with the precision of about 10% at the relevant Gamow energy of 300 keV. The ERNA (European Recoil mass separator for Nuclear Astrophysics) collaboration measured, for the first time, the total cross section of 12C(α, γ)16O by means of the direct detection of the 16O ions produced in the reaction down to an energy of Ecm = 1.9 MeV. To extend the measurement at lower energy, it is necessary to limit the extension of the He gas target. This can be achieved using a supersonic jet, where the oblique shock waves and expansion fans formed at its boundaries confine the gas, which can be efficiently collected using a catcher. A test version of such a system has been designed, constructed and experimentally characterized as a bench mark for a full numerical simulation using FV (Finite Volume) methods. The results of the commissioning of the jet test version and the design of the new system that will be used in combination with ERNA are presented and discussed.

  8. High Resolution Measurement of the ^16O(γ,pn)^14N_0,1,2... Reaction

    NASA Astrophysics Data System (ADS)

    Garrow, Kenneth; Pywell, Rob; Kolb, Norm; Adimi, Farida; Vogt, Johannes; Jury, Jim; Thompson, Max; Kuzin, Alex

    1997-10-01

    Results of the ^16O(γ,pn)^14N_0,1,2... measurement will be presented. This measurement used the photon tagging facility located at the University of Saskatchewan Accelerator Laboratory. The tagged photon energy range was from 100 to 140 MeV. Events in which the photon interacted within the nucleus resulting in the simultaneous emission of a proton and a neutron were recorded. The protons were detected using high resolution CsI(Tl) detectors while the neutron's energy was determined by a time-of-flight measurement. In order to reconstruct the residual states in ^14N a net missing energy resolution of approximately 2 MeV FWHM was desired. By resolving the residual states and using the known spin, parity and isospin, information about the quantum numbers of the two nucleon photoabsortion mechanism can be extracted within the frame work of a spectator model for the recoil ^14N nucleus.

  9. Computational study of the influence of solvent on (16)O/(18)O equilibrium isotope effects in phosphate deprotonation reactions.

    PubMed

    Kolmodin, Karin; Luzhkov, Victor B; Aqvist, Johan

    2002-08-28

    Results from theoretical calculations of (16)O/(18)O equilibrium isotope effects (EIEs) on deprotonation of phosphate and methyl phosphate monoanions as well as their deuterated counterparts are reported. The EIEs are calculated from the Bigeleisen equation using harmonic vibrational frequencies from several quantum mechanical methods (HF, DFT, MP2, and AM1). All methods correctly predict the qualitative trends in the EIEs related to the different isotope substitutions. However, the calculated gas-phase values are found to be systematically higher than those experimentally observed in aqueous solution. On the other hand, the addition of explicit solvent molecules (up to 24 waters) in the first solvation shells of the phosphate ion substantially improves the calculated EIE, which approaches the experimental value with increasing size of the water cluster. The large effects of surrounding water molecules on the phosphate deprotonation EIE can be explained by the strong solute-solvent interactions, which result in solvent coupled vibrational modes of the phosphate ions.

  10. 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.

  11. The fluorine destruction in stars: First experimental study of the {sup 19}F(p,{alpha}){sup 16}O reaction at astrophysical energies

    SciTech Connect

    La Cognata, M.; Mukhamedzhanov, A.; Spitaleri, C.; Indelicato, I.; Aliotta, M.; Burjan, V.; Cherubini, S.; Coc, A.; Gulino, M.; Hons, Z.; Kiss, G. G.; Kroha, V.; Lamia, L.; Mrazek, J.; Palmerini, S.; Piskor, S.; Pizzone, R. G.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; and others

    2012-11-12

    The {sup 19}F(p,{alpha}){sup 16}O reaction is an important fluorine destruction channel in the proton-rich outer layers of asymptotic giant branch (AGB) stars and it might also play a role in hydrogendeficient post-AGB star nucleosynthesis. So far, available direct measurements do not reach the energy region of astrophysical interest (E{sub cm}{approx} 300 keV), because of the hindrance effect of the Coulomb barrier. The Trojan Horse (TH) method was thus used to access this energy region, by extracting the quasi-free contribution to the {sup 2}H({sup 19}F,{alpha}{sup 16}O)n reaction. The TH measurement of the {alpha}{sub 0} channel, which is the dominant one at such energies, shows the presence of resonant structures not observed before that cause an increase of the reaction rate at astrophysical temperatures up to a factor of 1.7, with potential important consequences for stellar nucleosynthesis.

  12. 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.

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

    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.

    2014-05-01

    The 13C(α,n)16O 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 17O. 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 13C(6Li,n16O)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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Sensitivity of fusion and quasi-elastic barrier distributions of {sub 16}O+{sub 144}Sm reaction on the coupling radius parameter

    SciTech Connect

    Zamrun, Muhammad; Usman, Ida; Variani, Viska Inda; Kassim, Hasan Abu

    2014-03-05

    We study the heavy-ion collision at sub-barrier energies of {sub 16}O+{sub 144}Sm system using full order coupled-channels formalism. We especially investigate the sensitivity of fusion and quasi-elastic barrier distributions for this system on the coupling radius parameter. We found that the coupled-channels calculations of the fusion and the quasi-elastic barrier distributions are sensitive to the coupling radius for this reaction in contrast to the fusion and quasi-elastic cross section. Our study indicates that the larger coupling radius, i.e., r{sub coup}=1.20, is required by the experimental quasi-elastic barrier distribution. However, the experimental fusion barrier distribution compulsory the small value, i.e., r{sub coup}=1.06.

  19. Microscopic time-dependent description of alpha-cluster transfer and incomplete fusion in reactions with 12C and 16O near Coulomb barrier

    NASA Astrophysics Data System (ADS)

    Samarin, V. V.

    2017-06-01

    The time-dependent Schrödinger equation has been numerically solved for the α-cluster wave function the in reaction 12C+51V at the energies near and above the Coulomb barrier. The α-target potential included an imaginary part as in the optical model. The α-cluster mean field of the shell model for 12C and 16O nuclei based on the results of Feynman’s integrals method is proposed. The evolution of the α-cluster probability density was calculated for the complete and incomplete fusion as well as transfer channels. The calculated cross sections show satisfactory agreement with the experimental data for (12C,α) and (12C,2α) transfer channels.

  20. Dynamics of the quasielastic 16O (e, e' p) reaction at Q2 ≈ 0.8 (GeV/c)2

    NASA Astrophysics Data System (ADS)

    Fissum, K. G.; Liang, M.; 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. S.; Cates, G. D.; Cavata, C.; Chang, C. C.; Chen, J.-P.; Cisbani, E.; Dale, D. S.; de Jager, C. W.; de Leo, R.; Deur, A.; Diederich, B.; Djawotho, P.; Domingo, J.; Ducret, J.-E.; Epstein, M. B.; Ewell, L. A.; Finn, J. M.; 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.; 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.; Lindgren, R. A.; Liyanage, N.; 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.; Wojtsekhowski, B.; Zainea, D. G.; Zeps, V.; Zhao, J.; Zhou, Z.-L.; Udías, J. M.; Vignote, J. R.; Ryckebusch, J.; Debruyne, D.

    2004-09-01

    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,ω) kinematics at Q2 ≈0.8 (GeV/c)2 , q≈1 GeV/c , and ω≈445 MeV . Use of a self-calibrating, self-normalizing, thin-film waterfall target enabled a systematically rigorous measurement. Five-fold differential cross-section data for the removal of protons from the 1p -shell have been obtained for 0< pmiss <350 MeV/c . Six-fold differential cross-section data for 0< Emiss <120 MeV were obtained for 0< pmiss <340 MeV/c . These results have been used to extract the ALT asymmetry and the RL , RT , RLT , and RL+TT effective response functions over a large range of Emiss and pmiss . Detailed comparisons of the 1p -shell data with Relativistic Distorted-Wave Impulse Approximation (RDWIA), Relativistic Optical-Model Eikonal Approximation (ROMEA), and Relativistic Multiple-Scattering Glauber Approximation (RMSGA) calculations indicate that two-body currents stemming from meson-exchange currents (MEC) and isobar currents (IC) are not needed to explain the data at this Q2 . Further, dynamical relativistic effects are strongly indicated by the observed structure in ALT at pmiss ≈300 MeV/c . For 25< Emiss <50 MeV and pmiss ≈50 MeV/c , proton knockout from the 1 s1/2 -state dominates, and ROMEA calculations do an excellent job of explaining the data. However, as pmiss increases, the single-particle behavior of the reaction is increasingly hidden by more complicated processes, and for 280< pmiss <340 MeV/c , ROMEA calculations together with two-body currents stemming from MEC and IC account for the shape and transverse nature of the data, but only about half the magnitude of the measured cross section. For 50< Emiss <120 MeV and 145< pmiss <340 MeV/c , (e, e' pN) calculations which include the contributions of central and tensor correlations (two-nucleon correlations) together with MEC and IC (two

  1. Four-body calculation of {sup 12}C(α, γ){sup 16}O radiative capture reaction at stellar energies

    SciTech Connect

    Sadeghi, H.; Firoozabadi, M. M.

    2016-01-15

    On the basis of the four-alphamodel, the {sup 12}C(α, γ){sup 16}Oradiative capture process is investigated by using the four-body Faddeev–Yakubovsky equations as well as the two- and three-body electromagnetic currents. The present calculation is an application of our current conservation realistic potentials method for the {sup 12}C(α, γ){sup 16}Oradiative capture process. This work clears the way formore refinedmodels of radiative capture based on two- and three-body realistic potentials and current conservation. The calculation is carried out by considering the {sup 4}He + {sup 12}C (1 + 3) and the {sup 8}Be + {sup 8}Be (2 + 2) subamplitudes, respectively. Radiative capture {sup 12}C(α, γ){sup 16}Oreaction is one of the most important reactions in nuclear astrophysics. For this reaction, the electric dipole transitions between states with the same isospin are forbidden in the first order. Because the state 1{sup +} and 0{sup +} ground state nuclei {sup 16}O have zero isospin, thus the electric dipole radiations are not at the first order between two levels and electric dipole radiation will be the second order and electric dipole radiation is the same order as the electric quadrupole radiation. Therefore, we must consider the effects of both radiations. In comparison with other theoretical methods and available experimental data, good agreement is achieved for the E{sub 1} and E{sub 2} contribution to the cross section and the astrophysical S factor for this process.

  2. 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.

  3. A proposed direct measurement of cross section at Gamow window for key reaction 19F(p,α) 16O in Asymptotic Giant Branch stars with a planned accelerator in CJPL

    NASA Astrophysics Data System (ADS)

    He, JianJun; Xu, ShiWei; Ma, ShaoBo; Hu, Jun; Zhang, LiYong; Fu, ChangBo; Zhang, NingTao; Lian, Gang; Su, Jun; Li, YunJu; Yan, ShengQuan; Shen, YangPing; Hou, SuQing; Jia, BaoLu; Zhang, Tao; Zhang, XiaoPeng; Guo, Bing; Kubono, Shigeru; Liu, WeiPing

    2016-05-01

    In 2014, the National Natural Science Foundation of China (NSFC) approved the Jinping Underground Nuclear Astrophysics laboratory (JUNA) project, which aims at direct cross-section measurements of four key stellar nuclear reactions right down to the Gamow windows. In order to solve the observed fluorine overabundances in Asymptotic Giant Branch (AGB) stars, measuring the key 19F(p,α)16O reaction at effective burning energies (i.e., at Gamow window) is established as one of the scientific research sub-projects. The present paper describes this sub-project in details, including motivation, status, experimental setup, yield and background estimation, aboveground test, as well as other relevant reactions.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Measurement of the -3 keV resonance in the {sup 13}C({alpha},n){sup 16}O reaction and its influence on the synthesis of s-process nuclei

    SciTech Connect

    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.; Sparta, R.; and others

    2012-11-20

    The {sup 13}C({alpha},n){sup 16}O 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 < 10{sup 8} K, corresponding to an energy interval where the {sup 13}C({alpha},n){sup 16}O 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 {sup 17}O, 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 {sup 13}C({sup 6}Li,n{sup 16}O)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 {sup 13}C({alpha},n){sup 16}O 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.

  9. 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.

  10. 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%.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. The breakup of (16)O and its astrophysical implications

    NASA Astrophysics Data System (ADS)

    Bryan, Diane Carol

    1998-07-01

    The feasibility of using the breakup of 16O to obtain information about the 12C(/alpha,/gamma)16O radiative capture reaction has been studied in a series of experiments performed at the Nuclear Structure Research Laboratory at the University of Rochester. The 16O breakup fragments-12C and 4He-were identified using a new focal-plane detector capable of identifying these fragments down to a relative energy of 50 keV. The relative energy spectra obtained from 16O breakup on a 58Ni target are dominated by sequential breakup from 9.85 MeV, and 10.36 MeV excited states in 16O. There is also some evidence of breakup at relative energies below 1 MeV. Interpretation of this low energy yield in terms of E2 Coulomb excitation leads to a value of SE2=346 keV b at Erel=0.828 MeV after making a correction for the contribution due to nuclear breakup. This suggests that the rate of the 12C(/alpha,/gamma)16O reaction at astrophysical energies is much higher than is presently accepted, which would have an enormous impact on stellar nucleosynthesis.

  19. 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.

  20. Isospin effects on fragmentation in the asymmetric reactions induced by neutron-rich targets

    SciTech Connect

    Sharma, Arun

    2016-05-06

    To understand the isospin effects in terms of fragment’s yield in the asymmetric reactions induced by neutron-rich targets, we perform a theoretical study using isospin-dependent quantum molecular dynamics (IQMD) model. Simulations are carried out for reactions of {sup 16}O+Br{sup 80,84,92} and {sup 16}O+Ag{sup 108,113,122}. We envision that fragments’s yield in the asymmetric collisions induced by neutron-rich targets is better candidate to study isospin effects via symmetry energy and nucleon-nucleon (nn) cross-sections. Also, pronounced effects of symmetry energy and cross-sections can be found at lower and higher beam energies, respectively.

  1. 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.

  2. 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.

  3. Production of thin targets by implantation for the measurement of the 16O + 16O elastic scattering below the Coulomb barrier

    NASA Astrophysics Data System (ADS)

    Silva, H.; Cruz, J.; Sánchez-Benítez, A. M.; Santos, C.; Luís, H.; Fonseca, M.; Jesus, A. P.

    2017-09-01

    In recent decades, the processes of fusion of 16O were studied both theoretically and experimentally. However, the theoretical calculations are unable to fit both elastic scattering cross sections and fusion S-factors. The use of 16O thin transmission targets is required to measure the elastic forward scattering 16O + 16O reaction. The areal density of the target must be high to maximize the reaction products yields, but not so high as to allow a correct calculation of the effective beam energy. Besides this, the target must withstand beam interactions without noticeable deterioration, and contaminants must be minimal. In this study, the production of thin targets is performed with an innovative technique. Beam characterization and preliminary spectrum for the elastic scattering are also presented, showing the suitability of these targets for the proposed reaction.

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. Quadrupole contributions to 10,11B + 16O elastic scattering

    NASA Astrophysics Data System (ADS)

    Parks, L. A.; Stanley, D. P.; Courtney, L. H.; Kemper, K. W.

    1980-01-01

    Elastic scattering angular distributions have been measured for the systems 10B + 16O at EL=33.7, 41.6, and 49.5 MeV and 11B + 16O at EL=41.6 and 49.5 MeV. The 10B and 11B data are oscillatory and similar for angles less than 50° c.m. For angles greater than 50° c.m., the oscillations in the 10B data are damped and the data stop decreasing with increasing angle. Elastic scattering angular distributions have been calculated for 10,11B + 16O with the coupling to the ground-state quadrupole moment included explicitly. Potentials which describe the scattering are extracted with the double folding model. It is found that the quadrupole coupling is necessary to explain the difference in 10B and 11B scattering from 16O. NUCLEAR REACTIONS 16O (10B, 10B) 16O, EL=33.7, 41.6, and 49.5 MeV, 16O (11B, 11B) 16O, EL=41.6 and 49.5 MeV. Measured σ(θ), deduced Woods-Saxon, and double-folding model parameters. Coupled channels calculations for the ground-state quadrupole moment contributions.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Nuclear Reactions Induced by a Pyroelectric Accelerator

    SciTech Connect

    Geuther, Jeffrey; Danon, Yaron; Saglime, Frank

    2006-02-10

    This work demonstrates the use of pyroelectric crystals to induce nuclear reactions. A system based on a pair of pyroelectric crystals is used to ionize gas and accelerate the ions to energies of up to 200 keV. The system operates above room temperature by simply heating or cooling the pyroelectric crystals. A D-D fusion reaction was achieved with this technique, and 2.5 MeV neutrons were detected. The measured neutron yield is in good agreement with the calculated yield. This work also verifies the results published by Naranjo, Gimzewski, and Putterman [Nature (London) 434, 1115 (2005)].

  15. 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

  16. 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).

  17. 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).

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. On the electron-induced isotope fractionation in low temperature (32)O(2)/(36)O(2) ices--ozone as a case study.

    PubMed

    Sivaraman, B; Mebel, A M; Mason, N J; Babikov, D; Kaiser, R I

    2011-01-14

    The formation of six ozone isotopomers and isotopologues, (16)O(16)O(16)O, (18)O(18)O(18)O, (16)O(16)O(18)O, (18)O(18)O(16)O, (16)O(18)O(16)O, and (18)O(16)O(18)O, has been studied in electron-irradiated solid oxygen (16)O(2) and (18)O(2) (1 ∶ 1) ices at 11 K. Significant isotope effects were found to exist which involved enrichment of (18)O-bearing ozone molecules. The heavy (18)O(18)O(18)O species is formed with a factor of about six higher than the corresponding (16)O(16)O(16)O isotopologue. Likewise, the heavy (18)O(18)O(16)O species is formed with abundances of a factor of three higher than the lighter (16)O(16)O(18)O counterpart. No isotope effect was observed in the production of (16)O(18)O(16)O versus(18)O(16)O(18)O. Such studies on the formation of distinct ozone isotopomers and isotopologues involving non-thermal, non-equilibrium chemistry by irradiation of oxygen ices with high energy electrons, as present in the magnetosphere of the giant planets Jupiter and Saturn, may suggest that similar mechanisms may contribute to the (18)O enrichment on the icy satellites of Jupiter and Saturn such as Ganymede, Rhea, and Dione. In such a Solar System environment, energetic particles from the magnetospheres of the giant planets may induce non-equilibrium reactions of suprathermal and/or electronically excited atoms under conditions, which are quite distinct from isotopic enrichments found in classical, thermal gas phase reactions.

  4. 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.

  5. Searching for ^16^O^18^O.

    NASA Astrophysics Data System (ADS)

    Marechal, P.; Pagani, L.; Langer, W. D.; Castets, A.

    1997-02-01

    After our first tentative detection of the molecular oxygen ^16^O^18^O isotopomer obtained during the winter '92/93 (Pagani et al. 1993), we attempted to confirm our results by making a deep search in other sources and in other positions in L134N. We have not been able to confirm the original detection in any other place in L134N but we obtain good upper limits towards NGC 2264(IRS2), TMC2, OMC3 and L134N (4', -1') and (5.2', -1) which give an O_2_/CO ratio upper limit near 0.1 -- the lowest yet obtained toward galactic sources -- instead of 0.3-0.4 as predicted by gas phase chemical equilibrium models. As our sample consists of eight cold or lukewarm dark clouds, the low abundance of O_2_ with respect to CO seems to be a general characteristic of dark clouds.

  6. 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.

  7. 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.

  8. 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.

  9. Measurement and extrapolation of total cross sections of 12C+16O fusion at stellar energies

    NASA Astrophysics Data System (ADS)

    Fang, Xiao

    Carbon burning and oxygen burning in massive stars (M ≥ 8M[special character omitted]) are important burning phases in late stellar evolution following helium burning. They determined the nucleosynthesis phases and the initial matter distribution. Hydrostatic burning of 12C and 16O at lower temperatures remains an important feature. The critical reactions are the 12C+12C, 12C+ 16O and 16O+16O fusion processes. Extensive effort, both experimentally and theoretically, has been invested in the determination of the reaction rates for all reaction channels. Despite this effort, there remain large uncertainties in the predicted results that rely primarily on the extrapolation of the data into the Gamow range. The predicted results depend sensitively on the adopted model parameters, hindrance effects, and the possibility of resonances at relevant energies. The astrophysical important energy range of the 12C+12C fusion reaction spans from 1.0 MeV to 3.0 MeV. However, its cross section has not been determined with enough precision, despite numerous studies, due to the extremely low reaction cross sections and the large experimental background. The 12C+16O is difficult for experimental measurement due to the same reason. To allow measurements of the 12C+ 12C and 12C+16O fusions at astrophysical energies, a large-area silicon strip detector array was developed. The total cross section of the 12C+16O fusion has been measured at low energies using the St Ana 5MV accelerator at the University of Notre Dame. A high-intensity oxygen beam was produced impinging on a thick ultra-pure graphite target. Protons and gamma-rays have been measured simultaneously in the center-of-mass energy range of 3.64 to 4.93 MeV, using silicon and HPGe detectors. Statistical model calculations were employed to interpret the experimental results. This provides a more reliable extrapolation for the 12C+16O fusion cross section reducing substantially the uncertainty for stellar model simulations.

  10. 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.

  11. Inelastic pion double charge exchange on /sup 16/O at 240 MeV

    SciTech Connect

    Mischke, R.E.; Blomberg, A.; Gram, P.A.M.; Jansen, J.; Zichy, J.; Bolger, J.; Boschitz, E.; Ingram, C.H.Q.; Proebstle, G.

    1980-05-05

    The deep-inelastic double-charge-exchange reaction /sup 16/O(..pi../sup +/,..pi../sup -/) has been measured at 50/sup 0/, 85/sup 0/, and 130/sup 0/ with 240-MeV incident pions. The doubly differential cross section is peaked at low outgoing pion energies, as is expected from a double-scattering process, and is nearly isotropic. The integrated cross section is 5.8 +- 0.9 mb. The shape of the differential cross section suggests that the low-energy tail in /sup 16/O(..pi../sup +/,..pi../sup +prime/) scattering at the same energy also arises from double scattering.

  12. Isorefractive high internal phase emulsion organogels for light induced reactions.

    PubMed

    Zhang, Tao; Guo, Qipeng

    2016-03-25

    Isorefractive high internal phase emulsion (HIPE) organogels have been fabricated and investigated for light induced reactions. High transparency facilitates both the UV and visible light induced reactions within HIPE organogels. Transparent HIPE organogels are advantageous for light induced polymerizations, accelerating such polymerizations and enabling the preparation of large polyHIPE monoliths.

  13. 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.

  14. 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.

  15. Chemotherapy and biotherapy-induced hypersensitivity reactions.

    PubMed

    Van Gerpen, Ruth

    2009-01-01

    Nearly all chemotherapy and biotherapy drugs used in cancer treatment today can cause hypersensitivity reactions. Certain groups of drugs frequently associated with these reactions include the asparaginases, taxanes, platinum compounds, epipodophyllotoxins, and the monoclonal antibodies. Recognizing and managing hypersensitivity reactions are critical when caring for patients receiving these drugs because the reactions are potentially life-threatening. A thorough understanding of the drugs is necessary to assist the nurse in prevention, early recognition, and timely management.

  16. 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.

  17. Measurement of γ-rays from Giant Resonances of 16O and 12C with Application to Supernova Neutrino Detection

    NASA Astrophysics Data System (ADS)

    Ou, Iwa; Yamada, Yoshiyuyki; Shirahige, Tetsuya; Fukuda, Daisuke; Yano, Takatomi; Mori, Takaaki; Koshio, Yusuke; Sakuda, Makoto; Dhir, Rohit; Tamii, Atsushi; Aoi, Nori; Yosoi, Masaru; Ideguchi, Eiji; Suzuki, Tomokazu; Iwamoto, Chihiro; Ito, Takeshi; Miura, Masaki; Yamamoto, Tetsuya; Kawabata, Takahiro; Adachi, Satoshi; Tsumura, Miho; Murata, Motoki; Furuno, Tatsuya; Akimune, Hidetoshi; Nakada, Hitoshi

    We report preliminary results on the detection of the γ-rays from giant resonances of 16O and 12C nuclei from the experiment carried out at Research Center for Nuclear Physics Osaka University. These γ-rays can be used to detect the μ and τ type neutrinos and anti-neutrinos, emitted from a core-collapse supernova, through neutral current reactions with 16O and 12C by large-scale neutrino detectors.

  18. 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

  19. Search for dilute excited states in 16O

    NASA Astrophysics Data System (ADS)

    Ogloblin, A. A.; Danilov, A. N.; Demyanova, A. S.; Goncharov, S. A.; Belyaeva, T. L.

    2016-11-01

    The root mean square radii of 16O in the short-lived 0+ excited states were experimentally deduced for the first time from the analyses of α +16O diffraction scattering. Differential cross sections of the elastic and inelastic α +16O and 16O+16O scattering in the incident energy range from a few MeV/nucleon up to 100 MeV/nucleon were analyzed by the modified diffraction model. No significant radius enhancement in any state in comparison with the ground state was observed. This concerns, in particular, the 15.1-MeV 06+ state of 16O, located in the vicinity of the four-α -particle complete dissociation threshold, for which we did not confirm the "gigantic" size predicted by the α -particle condensation model. This result does not support the idea that 16O in the 06+ state has a dilute structure and can be considered as an analog of the famous 7.65-MeV 02+ Hoyle state of 12C.

  20. 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.

  1. 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.

  2. 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.

  3. Adverse drug reactions induced by valproic acid.

    PubMed

    Nanau, Radu M; Neuman, Manuela G

    2013-10-01

    Valproic acid is a widely-used first-generation antiepileptic drug, prescribed predominantly in epilepsy and psychiatric disorders. VPA has good efficacy and pharmacoeconomic profiles, as well as a relatively favorable safety profile. However, adverse drug reactions have been reported in relation with valproic acid use, either as monotherapy or polytherapy with other antiepileptic drugs or antipsychotic drugs. This systematic review discusses valproic acid adverse drug reactions, in terms of hepatotoxicity, mitochondrial toxicity, hyperammonemic encephalopathy, hypersensitivity syndrome reactions, neurological toxicity, metabolic and endocrine adverse events, and teratogenicity. Copyright © 2013 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  4. 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.

  5. 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.

  6. 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

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

    PubMed

    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

    2009-07-14

    The stratospheric CO(2) oxygen isotope budget is thought to be governed primarily by the O((1)D)+CO(2) 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 CO(2) isotopologue (16)O(13)C(18)O, in concert with (18)O and (17)O 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 (16)O(13)C(18)O, observed as proportions in the polar vortex that are higher than in any naturally derived CO(2) sample to date. We show, through photochemical experiments, that lower (16)O(13)C(18)O proportions observed in the midlatitudes are determined primarily by the O((1)D)+CO(2) isotope exchange reaction, which promotes a stochastic isotopologue distribution. In contrast, higher (16)O(13)C(18)O 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((1)D)+CO(2). We believe the most plausible explanation for this meridional variation is either an unrecognized isotopic fractionation associated with the mesospheric photochemistry of CO(2) or temperature-dependent isotopic exchange on polar stratospheric clouds. Unraveling the ultimate source of stratospheric (16)O(13)C(18)O enrichments may impose additional isotopic constraints on biosphere-atmosphere carbon exchange, biosphere productivity, and their respective responses to climate change.

  8. 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.

  9. Morphological changes of amphiphilic molecular assemblies induced by chemical reactions.

    PubMed

    Nakagawa, Koh M; Noguchi, Hiroshi

    2015-02-04

    Shape transformations of amphiphilic molecular assemblies induced by chemical reactions are studied using coarse-grained molecular simulations. A binding reaction between hydrophilic and hydrophobic molecules is considered. It is found that the reaction induces transformation of an oil droplet to a tubular vesicle via bicelles and vesicles with discoidal arms. The discoidal arms close into vesicles, which are subsequently fused into the tubular vesicle. Under the chemical reaction, the bicelle-to-vesicle transition occurs at smaller sizes than in the absence of the hydrophobic molecules. It is revealed that the enhancement of this transition is due to embedded hydrophobic particles that reduce the membrane bending rigidity.

  10. 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.

  11. 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.

  12. 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.

  13. [Adverse reactions induced by food additives: sulfites].

    PubMed

    Montaño García, M L

    1989-01-01

    Many chemicals are used to preserve, color and flavor foods and drugs. There have been numerous reports of adverse reactions, including urticaria, angioneurotic edema, asthma an anaphylaxis following the ingestion of food additives such as tartrazine, monosodium glutamate and benzoic acid. Recently the food and drug additives reaching medical awareness as a cause of sensitivity are the sulfiting agents. Sulfites are widely used in the food and beverage industry as preservatives and antioxidants. They are also used by the pharmaceutical industry. This work describes the common uses of sulfiting agents, the mechanisms of sulfite sensitivity, the diagnosis, prevention and treatment of adverse reactions to sulfites.

  14. Nuclear Astrophysics and Neutron Induced Reactions: Quasi-Free Reactions and RIBs

    SciTech Connect

    Cherubini, S.; Spitaleri, C.; Crucilla, V.; Gulino, M.; La Cognata, M.; Lamia, L.; Pizzone, R. G.; Puglia, S.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Coc, A.; Kubono, S.; Binh, D. N.; Hayakawa, S.; Wakabayashi, Y.; Yamaguchi, H.; Burjan, V.; Kroha, V.; De Sereville, N.

    2010-08-12

    The use of quasi-free reactions in studying nuclear reactions between charged particles of astrophysical interest has received much attention over the last two decades. The Trojan Horse Method is based on this approach and it has been used to study a number of reactions relevant for Nuclear Astrophysics. Recently we applied this method to the study of nuclear reactions that involve radioactive species, namely to the study of the {sup 18}F+p{yields}{sup 15}O+{alpha} process at temperatures corresponding to the energies available in the classical novae scenario. Quasi-free reactions can also be exploited to study processes induced by neutrons. This technique is particularly interesting when applied to reaction induced by neutrons on unstable short-lived nuclei. Such processes are very important in the nucleosynthesis of elements in the sand r-processes scenarios and this technique can give hints for solving key questions in nuclear astrophysics where direct measurements are practically impossible.

  15. 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

  16. 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

  17. 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

  18. Trojan Horse Method for neutrons-induced reaction studies

    NASA Astrophysics Data System (ADS)

    Gulino, M.; Asfin Collaboration

    2017-09-01

    Neutron-induced reactions play an important role in nuclear astrophysics in several scenario, such as primordial Big Bang Nucleosynthesis, Inhomogeneous Big Bang Nucleosynthesis, heavy-element production during the weak component of the s-process, explosive stellar nucleosynthesis. To overcome the experimental problems arising from the production of a neutron beam, the possibility to use the Trojan Horse Method to study neutron-induced reactions has been investigated. The application is of particular interest for reactions involving radioactive nuclei having short lifetime.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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).

  7. 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.

  8. Low-energy electron-induced reactions in condensed matter

    NASA Astrophysics Data System (ADS)

    Arumainayagam, Christopher R.; Lee, Hsiao-Lu; Nelson, Rachel B.; Haines, David R.; Gunawardane, Richard P.

    2010-01-01

    The goal of this review is to discuss post-irradiation analysis of low-energy (≤50 eV) electron-induced processes in nanoscale thin films. Because electron-induced surface reactions in monolayer adsorbates have been extensively reviewed, we will instead focus on low-energy electron-induced reactions in multilayer adsorbates. The latter studies, involving nanoscale thin films, serve to elucidate the pivotal role that the low-energy electron-induced reactions play in high-energy radiation-induced chemical reactions in condensed matter. Although electron-stimulated desorption (ESD) experiments conducted during irradiation have yielded vital information relevant to primary or initial electron-induced processes, we wish to demonstrate in this review that analyzing the products following low-energy electron irradiation can provide new insights into radiation chemistry. This review presents studies of electron-induced reactions in nanoscale films of molecular species such as oxygen, nitrogen trifluoride, water, alkanes, alcohols, aldehydes, ketones, carboxylic acids, nitriles, halocarbons, alkane and phenyl thiols, thiophenes, ferrocene, amino acids, nucleotides, and DNA using post-irradiation techniques such as temperature-programmed desorption (TPD), reflection-absorption infrared spectroscopy (RAIRS), X-ray photoelectron spectroscopy (XPS), high-resolution electron energy loss spectroscopy (HREELS), gel electrophoresis, and microarray fluorescence. Post-irradiation temperature-programmed desorption, in particular, has been shown to be useful in identifying labile radiolysis products as demonstrated by the first identification of methoxymethanol as a reaction product of methanol radiolysis. Results of post-irradiation studies have been used not only to identify radiolysis products, but also to determine the dynamics of electron-induced reactions. For example, studies of the radiolysis yield as a function of incident electron energy have shown that dissociative

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. [Reaction mechanism studies of heavy ion induced nuclear reactions]. Annual progress report, [January 1992--February 1993

    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.

  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. Cavitation-induced reactions in high-pressure carbon dioxide.

    PubMed

    Kuijpers, M W A; van Eck, D; Kemmere, M F; Keurentjes, J T F

    2002-12-06

    The feasibility of ultrasound-induced in situ radical formation in liquid carbon dioxide was demonstrated. The required threshold pressure for cavitation could be exceeded at a relatively low acoustic intensity, as the high vapor pressure of CO2 counteracts the hydrostatic pressure. With the use of a dynamic bubble model, the formation of hot spots upon bubble collapse was predicted. Cavitation-induced radical formation was used for the polymerization of methyl methacrylate in CO2, yielding high-molecular-weight polymers. These results show that sonochemical reactions can be performed in dense-phase fluids, which allows the environmentally benign CO2 to replace conventional organic solvents in many reaction systems.

  16. 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.

  17. 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.

  18. Spectroscopic Parameters for Ozone and its Isotopes: Current Status, Prospects for Improvement, and the Identification of 16O16O17O and O-16O-16O-17 and O-16O-17O-16 Lines in Infrared Ground-Based and Stratospheric Solar Absorption Spectra

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Flaud, J.-M.; Goldman, A.; Perrin, A.; Camy-Peyret, C.; Smith, M. A. H.; Devi, V. Malathy; Benner, D. C.; Barbe, A.; Stephens, T. M.; hide

    1998-01-01

    We describe the updates to the spectroscopic parameters of ozone and its isotopes in the 1996 HITRAN compilation. Recent published studies not included in HITRAN are also summarized. Finally, we report the identification of infrared lines of the v(sub 3) bands of O-16O-16O-17 and O-16O-17O-16 in high-resolution solar spectra recorded by stratospheric balloon-borne and ground-based Fourier transform spectrometers.

  19. A theoretical study of deuteron-induced surrogate reactions

    NASA Astrophysics Data System (ADS)

    Carlson, B. V.; Capote, R.; Sin, M.

    2017-09-01

    We use the zero-range post-form DWBA approximation to calculate deuteron elastic and nonelastic breakup cross sections and estimate the breakup-fusion cross section that could serve as a surrogate for a neutron-induced reaction cross section. We compare the angular momentum dependence of the breakup-fusion compound nucleus formation cross section with that of the corresponding neutron-induced cross section.

  20. A Theoretical Study of Deuteron-induced Surrogate Reactions

    NASA Astrophysics Data System (ADS)

    Carlson, B. V.; Capote, R.; Sin, M.

    2017-06-01

    We use the zero-range post-form DWBA approximation to calculate deuteron elastic and nonelastic breakup cross sections and estimate the breakup-fusion cross section that could serve as a surrogate for a neutron-induced reaction cross section. We compare the angular momentum dependence of the breakup-fusion compound nucleus formation cross section with that of the corresponding neutron-induced cross section.

  1. 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.

  2. 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.

  3. 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.

  4. 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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. 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.

  6. 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.

  7. 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

  8. Control of serpentinisation rate by reaction-induced cracking

    NASA Astrophysics Data System (ADS)

    Malvoisin, Benjamin; Brantut, Nicolas; Kaczmarek, Mary-Alix

    2017-10-01

    Serpentinisation of mantle rocks requires the generation and maintenance of transport pathways for water. The solid volume increase during serpentinisation can lead to stress build-up and trigger cracking, which ease fluid penetration into the rock. The quantitative effect of this reaction-induced cracking mechanism on reactive surface generation is poorly constrained, thus hampering our ability to predict serpentinisation rate in geological environments. Here we use a combined approach with numerical modelling and observations in natural samples to provide estimates of serpentinisation rate at mid-ocean ridges. We develop a micromechanical model to quantify the propagation of serpentinisation-induced cracks in olivine. The maximum crystallisation pressure deduced from thermodynamic calculations reaches several hundreds of megapascals but does not necessary lead to crack propagation if the olivine grain is subjected to high compressive stresses. The micromechanical model is then coupled to a simple geometrical model to predict reactive surface area formation during grain splitting, and thus bulk reaction rate. Our model reproduces quantitatively experimental kinetic data and the typical mesh texture formed during serpentinisation. We also compare the model results with olivine grain size distribution data obtained on natural serpentinised peridotites from the Marum ophiolite and the Papuan ultramafic belt (Papua New Guinea). The natural serpentinised peridotites show an increase of the number of olivine grains for a decrease of the mean grain size by one order of magnitude as reaction progresses from 5 to 40%. These results are in agreement with our model predictions, suggesting that reaction-induced cracking controls the serpentinisation rate. We use our model to estimate that, at mid-ocean ridges, serpentinisation occurs up to 12 km depth and reaction-induced cracking reduces the characteristic time of serpentinisation by one order of magnitude, down to values

  9. Evolution of a predator-induced, nonlinear reaction norm.

    PubMed

    Carter, Mauricio J; Lind, Martin I; Dennis, Stuart R; Hentley, William; Beckerman, Andrew P

    2017-08-30

    Inducible, anti-predator traits are a classic example of phenotypic plasticity. Their evolutionary dynamics depend on their genetic basis, the historical pattern of predation risk that populations have experienced and current selection gradients. When populations experience predators with contrasting hunting strategies and size preferences, theory suggests contrasting micro-evolutionary responses to selection. Daphnia pulex is an ideal species to explore the micro-evolutionary response of anti-predator traits because they face heterogeneous predation regimes, sometimes experiencing only invertebrate midge predators and other times experiencing vertebrate fish and invertebrate midge predators. We explored plausible patterns of adaptive evolution of a predator-induced morphological reaction norm. We combined estimates of selection gradients that characterize the various habitats that D. pulex experiences with detail on the quantitative genetic architecture of inducible morphological defences. Our data reveal a fine scale description of daphnid defensive reaction norms, and a strong covariance between the sensitivity to cues and the maximum response to cues. By analysing the response of the reaction norm to plausible, predator-specific selection gradients, we show how in the context of this covariance, micro-evolution may be more uniform than predicted from size-selective predation theory. Our results show how covariance between the sensitivity to cues and the maximum response to cues for morphological defence can shape the evolutionary trajectory of predator-induced defences in D. pulex. © 2017 The Authors.

  10. 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.

  11. 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

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. Bilateral activation of the abdominal muscles induces longer reaction time.

    PubMed

    Tsao, Henry; Overs, Michelle E; Wu, Jennifer C-Y; Galea, Mary P; Hodges, Paul W

    2008-05-01

    Bilateral deficit is the increase in reaction time during bilateral activation compared to unilateral activation. This has been reported extensively for the limb muscles and is argued to be due to concurrent inhibition through transcallosal pathways. Unlike the limb muscles, the axial muscles are commonly activated bilaterally during functional tasks and have bilateral projections to their motoneurones. Thus it is reasonable to hypothesise that there will be no bilateral deficit for these muscles. Recordings of electromyographic (EMG) activity were made using surface electrodes placed bilaterally over the abdominal muscles in eight healthy right-handed subjects. Subjects performed either right or left pelvic elevation (unilateral abdominal activation), or posterior pelvic tilt (bilateral abdominal activation) "as fast as possible" in response to an auditory tone. Movements were performed as either a simple or choice reaction time task. Bilateral activation induced significantly longer reaction time than unilateral activation, and was observed during both simple and choice reaction time tasks. The results demonstrate that reaction time is delayed during bilateral activation of the abdominal muscles. These findings suggest that bilateral deficit is present for the axial muscles. This could be mediated through inhibition at various levels of the nervous system or variations in postural demand.

  17. Proton-induced knockout reactions with polarized and unpolarized beams

    NASA Astrophysics Data System (ADS)

    Wakasa, T.; Ogata, K.; Noro, T.

    2017-09-01

    Proton-induced knockout reactions provide a direct means of studying the single particle or cluster structures of target nuclei. In addition, these knockout reactions are expected to play a unique role in investigations of the effects of the nuclear medium on nucleon-nucleon interactions as well as the properties of nucleons and mesons. However, due to the nature of hadron probes, these reactions can suffer significant disturbances from the nuclear surroundings and the quantitative theoretical treatment of such processes can also be challenging. In this article, we review the experimental and theoretical progress in this field, particularly focusing on the use of these reactions as a spectroscopic tool and as a way to examine the medium modification of nucleon-nucleon interactions. With regard to the former aspect, the review presents a semi-quantitative evaluation of these reactions based on existing experimental data. In terms of the latter point, we introduce a significant body of evidence that suggests, although does not conclusively prove, the existence of medium effects. In addition, this paper also provides information and comments on other related subjects.

  18. Ligand and Tetrathiometalate Effects in Induced Internal Electron Transfer Reactions.

    PubMed

    McConnachie, C. A.; Stiefel, E. I.

    1999-03-08

    New rhenium sulfide complexes, [Re(IV)(2)(&mgr;-S)(2)(&mgr;-S(2))(&mgr;-S(2)COR)(S(2)COR)(2)](-) and [Re(IV)(2)(&mgr;-S)(2)(S(2)COR)(4)], and a new tungsten sulfide complex, [WS(S(2))(S(2)CC(6)H(5))(2)], have been synthesized and isolated via induced internal redox reactions involving the appropriate tetrathiometalate and 1,1-dithiolate disulfide. The red complex [Re(IV)(2)(&mgr;-S)(2)(&mgr;-S(2))(&mgr;-S(2)COR)(S(2)COR)(2)](-), 1, was isolated from the reaction of dialkylxanthogen disulfide, [(ROCS(2))(2)], and tetraethylammonium tetrathioperrhenate, [Et(4)N][Re(VII)S(4)]. Crystal structure analysis of 1 reveals an edge-sharing (&mgr;-S)(2) bioctahedron containing both bridging disulfide and xanthate ligands. This reaction is compared to the known reaction between tetraalkylthiuram disulfide, [(R(2)NCS(2))(2)], and [Et(4)N][ReS(4)], which produces the green complex [Re(IV)(2)(&mgr;-S)(2)(S(2)CNR(2))(4)]. The corresponding green alkyl xanthate analogue, [Re(IV)(2)(&mgr;-S)(2)(S(2)COR)(4)], 2, was synthesized by a simple redox reaction between rhenium pentachloride, ReCl(5), and potassium alkyl xanthate, [K(S(2)COR)]. Comparing 1 with other known [ReS(4)](-)/1,1-dithiolate disulfide reaction products, such as [Re(IV)(2)(&mgr;-S)(2)(S(2)CNR(2))(4)] and [Re(III)(S(2)CC(6)H(5))(S(3)CC(6)H(5))(2)], shows a correlation between the electron-donating ability of the ligand and the nature of the reaction product. Reactions of [Et(4)N](2)[Mo(VI)S(4)], [Et(4)N][Re(VII)S(4)], or [Et(4)N](2)[W(VI)S(4)] with dithiobenzoate disulfide, [(S(2)CC(6)H(5))(2)], reveal a correlation between the ligand-to-metal charge transfer energy band (LMCT(1)) of the tetrathiometalate and the reaction product. The known purple complex [Mo(IV)(S(2)CC(6)H(5))(4)] and two new green complexes, [Re(III)(S(2)CC(6)H(5))(S(3)CC(6)H(5))(2)] (recently communicated) and [W(VI)S(S(2))(S(2)CC(6)H(5))(2)], were isolated from related reactions.

  19. 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.

  20. 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

  1. NN final-state interaction in two-nucleon knockout from 16O

    NASA Astrophysics Data System (ADS)

    Schwamb, M.; Boffi, S.; Giusti, C.; Pacati, F. D.

    . The influence of the mutual interaction between the two outgoing nucleons (NN-FSI) in electro- and photoinduced two-nucleon knockout from 16O has been investigated perturbatively. It turns out that the effect of NN-FSI depends on the kinematics and on the type of reaction considered. The effect is generally larger in pp- than in pn-knockout and in electroinduced than in photoinduced reactions. In superparallel kinematics NN-FSI leads in the (e,e`pp) channel to a strong increase of the cross-section, that is mainly due to a strong enhancement of the Δ -current contribution. In pn-emission, however, this effect is partially cancelled by a destructive interference with the seagull current. For photoreactions NN-FSI is considerably reduced in superparallel kinematics and can be practically negligible in specific kinematics.

  2. 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.

  3. 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.

  4. Trojan horse method with neutrons induced reactions: The 17O(n,α)14C reaction

    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.; O'Brien, S.; Pizzone, R. G.; Rapisarda, G. G.; Roberson, D.; Sergi, M. L.; Tan, W.; Wiescher, M.

    2017-06-01

    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 over-come 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. Moreover, the results show that the contribution of the 166 keV 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.

  5. Magnetic resonance studies of photo-induced electron transfer reactions

    SciTech Connect

    van Willigen, H.

    1992-11-01

    Fourier Transform Electron Paramagnetic Resonance (FT EPR) is useful in study of photochemical reactions: a microwave pulse rotates the electron spin magnetization vector from z (magnetic field) into xy plane ([pi]/2 pulse); the time evolution of magnetization in xy plane, the free induction decay (FID), is sampled. Fourier transform of FID gives the frequency domain EPR spectrum of the free radicals, and the method is ideal for time-resolved studies of free radicals produced by pulsed-laser excitation. Investigations of electron transfer reactions focused on porphyrin (donor) - quinone (acceptor) systems. First, two hydrogen abstraction reactions were studied with FT EPR: photoreduction of acetone with 2-propanol, yielding the acetone ketyl radical, and the reaction of 2-propanol with t-butoxy radicals. Then, the FT EPR study of benzoquinone or duroquinone anion radicals generated by pulsed-laser induced electron transfer from zinc tetraphenylporphyrin (ZnTPP) or tetrasulfonated Zn(TPP), was carried out in homogeneous solution, micellar solutions, and silica gel. Finally, FT EPR was used to study electron transfer quenching of triplet C[sub 60] by electron donors.

  6. 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.

  7. 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.

  8. 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.

  9. Granulomatous tattoo reaction induced by intense pulse light treatment.

    PubMed

    Tourlaki, Athanasia; Boneschi, Vinicio; Tosi, Diego; Pigatto, Paolo; Brambilla, Lucia

    2010-10-01

    Cosmetic tattooing involves implantation of pigments into the dermis in order to create a permanent makeup. Here, we report a case of sarcoidal granulomatous reaction to old cosmetic tattoos after an intense pulsed light (IPL) treatment for facial skin rejuvenation. We consider this case as a peculiar example of photo-induced reaction to tattoo. In addition, we hypothesize that an underlying immune dysfunction was present, and acted as a predisposing factor for this unusual response, as the patient had suffered from an episode of acute pulmonary sarcoidosis 15 years before. Overall, our observation suggests that IPL treatment should be used cautiously in patients with tattoos, especially when a history of autoimmune disease is present. © 2010 John Wiley & Sons A/S.

  10. 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

  11. 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.

  12. Proton inelastic scattering cross section measurements on 16O and 28Si

    NASA Astrophysics Data System (ADS)

    Boromiza, Marian; Borcea, Catalin; Dessagne, Philippe; Ghita, Dan; Glodariu, Tudor; Henning, Gregoire; Kerveno, Maëlle; Marginean, Nicolae; Mihai, Constantin; Negret, Alexandru; Nita, Cristina; Nyman, Markus; Olacel, Adina; Oprea, Andreea; Plompen, Arjan; Sotty, Christophe; Suliman, Gabriel; Suvaila, Rares; Stan, Lucian; Turturica, Andrei; Turturica, Gabriel

    2017-09-01

    A (p, p'γ) experiment was performed at the Tandem accelerator of IFIN-HH (Bucharest) with the purpose of measuring the proton inelastic cross-sections on 16O and 28Si. The goal was to investigate to which extent the neutron cross-sections on these nuclei can be inferred from those obtained with charged particles (i.e., protons). In doing so, we are trying to exploit the isospin symmetry by taking under consideration that the chosen targets are N = Z nuclei and, consequently, two mirror nuclei are formed in the (p,p') and (n,n') reactions. The experimental setup consisted of two HPGe detectors with 100% relative efficiency placed at 110∘ and 150∘ relative to the direction of the incident proton beam. The incident protons, which had energies ranging from 6 up to 17 MeV, were scattered on a thick quartz (SiO2) target. A Faraday cup was used to integrate the beam current, thus allowing an absolute determination of the γ production cross sections. We will briefly describe the data analysis procedure, the experimental particularities and difficulties and some preliminary results of the γ production cross sections for the most intense transitions both in 16O and 28Si.

  13. 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.

  14. [Adverse skin reactions induced by BRAF inhibitors: a systematic review].

    PubMed

    Sibaud, V; Lamant, L; Maisongrosse, V; Delord, J-P

    2013-01-01

    Recent developments and therapeutic use of selective BRAF inhibitors (e.g. dabrafenib and vemurafenib) have significantly improved overall survival and disease-free survival of patients with BRAF V600 mutation-positive metastatic melanoma. Despite their survival benefits, small-molecule inhibitors of BRAF are associated with significant and sometimes severe treatment-related dermatological toxicity. The most common adverse skin reactions include photosensitivity, induced malignant lesions of the skin such as keratoacanthomas, squamous cell carcinoma and new primary melanomas, as well as keratinocyte proliferation and differentiation dysfunctions that can manifest as skin papillomas, hand-foot skin reaction, keratosis pilaris-like rash, acantholytic dyskeratosis and cysts of the milia type. In this article, we describe the clinical and histological features of the cutaneous manifestations induced by vemurafenib and dabrafenib on the basis of our clinical experience and a literature review. The crucial role of dermatologists in patient management is also highlighted. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  15. Enhancing the branching ratios in the dissociation channels for O16O16O18 molecule by designing optimum laser pulses: A study using stochastic optimization

    NASA Astrophysics Data System (ADS)

    Talukder, Srijeeta; Sen, Shrabani; Shandilya, Bhavesh K.; Sharma, Rahul; Chaudhury, Pinaki; Adhikari, Satrajit

    2015-10-01

    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 (O18 + O16O16 and O16 + O16O18) in O16O16O18 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.

  16. Enhancing the branching ratios in the dissociation channels for O(16)O(16)O(18) molecule by designing optimum laser pulses: A study using stochastic optimization.

    PubMed

    Talukder, Srijeeta; Sen, Shrabani; Shandilya, Bhavesh K; Sharma, Rahul; Chaudhury, Pinaki; 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(18) + O(16)O(16) and O(16) + O(16)O(18)) in O(16)O(16)O(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.

  17. The isotopic ratios 17O/ 16O and 18O/ 16O in molecular oxygen and their significance in biogeochemistry

    NASA Astrophysics Data System (ADS)

    Luz, Boaz; Barkan, Eugeni

    2005-03-01

    Recently, a new method has been introduced for the estimation of photosynthetic oxygen production from the triple isotope composition (δ 17O and δ 18O) of dissolved O 2 in the ocean and of air O 2 in ice cores. This method is based on the deviations ( 17Δ) from mass dependent respiratory fractionation, the major process affecting the isotopic composition of air O 2. To apply this method, the slope in the 17O/ 16O vs. 18O/ 16O relationship used for 17Δ calculation must be known with high accuracy. Using numerical simulations and closed system experiments, we show how the respiratory slope is manifested in the 17Δ of O 2 in situations where respiration is the only process affecting oxygen isotopic composition (kinetic slope), and in systems in steady state between photosynthesis and respiration (steady state slope). The slopes of the fractionation line in these two cases are different, and the reasons of this phenomenon are discussed. To determine the kinetic respiratory slope for the dominant O 2 consumers in aquatic systems, we have conducted new experiments using a wide range of organisms and conditions and obtained one universal value (0.5179 ± 0.0006) in ln(δ 17O + 1) vs. ln(δ 18O + 1) plots. It was also shown that the respiratory fractionations under light and dark are identical within experimental error. We discuss various marine situations and conclude that the kinetic slope 0.518 should be used for calculating 17Δ of dissolved O 2. In contrast, a steady state fractionation slope should be used in global mass balance calculations of triple isotope ratios of O 2 in air records of ice cores.

  18. 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.

  19. Electronic circular dichroism of monomethyl [16O,17O,18O]-phosphate and [16O,17O,18O]-thiophosphate revisited.

    PubMed

    Pan, Jian-Jung; Kashemirov, Boris A; Lee, Joanne; McKenna, Charles E; Devlin, Frank J; Stephens, Philip J

    2010-02-01

    Phosphoryl-transfer reactions have long been of interest due to their importance in maintaining numerous cellular functions. A phosphoryl-transfer reaction results in two possible stereochemical outcomes: either retention or inversion of configuration at the transferred phosphorus atom. When the product is phosphate, isotopically-labeled [16O,17O,18O]-phosphate derivatives can be used to distinguish these outcomes; one oxygen must be replaced by sulfur or esterified to achieve isotopic chirality. Conventionally, stereochemical analysis of isotopically chiral phosphate has been based on 31P NMR spectroscopy and involves complex chemical or enzymatic transformations. An attractive alternative would be direct determination of the enantiomeric excess using chiroptical spectroscopy. (S)-Methyl-[16O,17O,18O]-phosphate (MePi*), 7 and enantiomeric [16O,17O,18O]-thiophosphate (TPi*), 10, were previously reported to exhibit weak electronic circular dichroism (ECD), although with 10 the result was considered to be uncertain. We have now re-examined the possibility that excesses of 7 and 10 enantiomers can be detected by ECD spectrometry, using both experimental and theoretical approaches. 7 and both the (R) and (S) enantiomers of 10 (10a,10b) were synthesized by the 'Oxford route' and characterized by 1H, 31P and 17O NMR, and by MS analysis. Weak ECD could be found for 7, with suboptimal S/N. No significant ECD could be detected for the 10 enantiomers. Time-dependent DFT (TDDFT) calculations of the electronic excitation energies and rotational strengths of the same three enantiomers were carried out using the functional B3LYP and the basis set 6-311G**. The isotopically-perturbed geometries were predicted using the anharmonic vibrational frequency calculational code in GAUSSIAN 03. In the case of 10, calculations were also carried out for the hexahydrated complex to investigate the influence of the aqueous solvent. The predicted excitation wavelengths are greater than the

  20. The role of primary 16O as a neutron poison in AGB stars and fluorine primary production at halo metallicities.

    NASA Astrophysics Data System (ADS)

    Gallino, R.; Bisterzo, S.; Cristallo, S.; Straniero, O.

    The discovery of a historical bug in the s-post-process AGB code obtained so far by the Torino group forced us to reconsider the role of primary 16O in the 13C-pocket, produced by the 13C(alpha , n)16O reaction, as important neutron poison for the build up of the s-elements at Halo metallicities. The effect is noticeable only for the highest 13C-pocket efficiencies (cases ST*2 and ST). For Galactic disc metallicities, the bug effect is negligible. A comparative analysis of the neutron poison effect of other primary isotopes (12C, 22Ne and its progenies) is presented. The effect of proton captures, by 14N(n, p)14C, boosts a primary production of fluorine in halo AGB stars, with [F/Fe] comparable to [C/Fe], without affecting the s-elements production.

  1. Reactions induced by low energy electrons in cryogenic films (Review)

    NASA Astrophysics Data System (ADS)

    Bass, A. D.; Sanche, L.

    2003-03-01

    We review recent research on reactions (including dissociation) initiated by low-energy electron bombardment of monolayer and multilayer molecular solids at cryogenic temperatures. With incident electrons of energies below 20 eV, dissociation is observed by the electron stimulated desorption (ESD) of anions from target films and is attributed to the processes of dissociative electron attachment (DEA) and to dipolar dissociation. It is shown that DEA to condensed molecules is sensitive to environmental factors such as the identity of co-adsorbed species and film morphology. The effects of image-charge induced polarization on cross sections for DEA to CH3Cl are also discussed. Taking as example, the electron-induced production of CO within multilayer films of methanol and acetone, it is shown that the detection of electronic excited states by high-resolution electron energy loss spectroscopy can be used to monitor electron beam damage. In particular, the incident energy dependence of the CO indicates that below 19 eV, dissociation proceeds via the decay of transient negative ions (TNI) into electronically excited dissociative states. The electron-induced dissociation of biomolecular targets is also considered, taking as examples the ribose analog tetrahydrofuran and DNA bases adenine and thymine, cytosine and guanine. The ESD of anions from such films also show dissociation via the formation of TNI. In multilayer molecular solids, fragment species resulting from dissociation, may react with neighboring molecules, as is demonstrated in anion ESD measurements from films containing O2 and various hydrocarbon molecules. X-ray photoelectron spectroscopy measurements reported for electron-irradiated monolayers of H2O and CF4 on a Si-H passivated surface further show that DEA is an important initial step in the electron-induced chemisorption of fragment species.

  2. 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.

  3. Dynamics of adsorbate rotation in electron-induced reaction

    NASA Astrophysics Data System (ADS)

    Hu, Zhixin; Anggara, Kelvin; Polanyi, John C.

    2017-09-01

    Molecular rotors at surfaces are of current interest. Here we employ molecular dynamics to examine rotation in the chemisorbed product, meta-iodophenyl, from electron-induced reaction of meta-diiodobenzene at a noble metal (M(1 1 0)). Electron attachment gives iodophenyl that rotates unidirectionally ('clockwise') around a carbon-metal (C-M) 'pivot bond', due to I-M attractions. Mobility is enhanced by tilting the phenyl. During rotation the I-atom of iodophenyl bounces off successive M-atoms. As M changes from Cu to Ag to Au, the surface increasingly damps the bounce, diminishing rotation. Reconstruction of the gold can cause the atomic pivot-point to shift substantially, thereby giving opposite 'anticlockwise' rotation.

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

    SciTech Connect

    Sadighi-Bonabi, Rasoul; Gheshlaghi, Maryam

    2016-03-15

    The Possibility of the laser assisted sonofusion is studied via single bubble sonoluminescence (SBSL) in Deuterated acetone (C{sub 3}D{sub 6}O) 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 × 10{sup 6} K in hydro-chemical model and it is reached up to 1.9 × 10{sup 6} K in the laser induced SBSL bubbles. Under these circumstances, temperature up to 10{sup 7} K can be produced in the center of the bubble in which the thermonuclear D-D fusion reactions are promising under the controlled conditions.

  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. 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.

  7. Structure effects on reaction mechanisms in collisions induced by radioactive ion beams

    SciTech Connect

    Pietro, A. Di Figuera, P.; Scuderi, V.; Amorini, F.; Angulo, C.; Cardella, G.; Casarejos, E.; Cherubini, S.; Lu, J.; Marchetta, C.; Musumarra, A.; Papa, M.; Pellegriti, M.; Pizzone, R. G.; Raabe, R.; Rizzo, F.; Sida, J. L.; Tian, W.

    2006-08-15

    The present paper concerns the study of reactions induced by radioactive beams of halo and weakly bound nuclei at energies around and above the Coulomb barrier. The results obtained for the reaction induced by the halo nucleus {sup 6}He on {sup 64}Zn have been compared with the results for the reaction induced by {sup 4}He on the same target. The results of the reaction induced by the weakly bound unstable {sup 13}N on the weakly bound {sup 9}Be have been compared with those for the reaction {sup 10}B + {sup 12}C.

  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. Neutron-Induced Reactions and Spectroscopy with GEANIE

    SciTech Connect

    Becker, J A; Nelson, R O

    2005-01-11

    A large number of partial {gamma}-ray cross sections produced in neutron-induced reactions with neutrons in the energy range 1 < E{sub n}(MeV) < 200 have been measured over the past eight years. Partial {gamma}-ray cross sections are measured as a function of incident neutron energy using the time-of-flight technique. Reaction channel cross sections were deduced from these measurements with the aid of nuclear modeling. Enabling facilities are the intense 'white' source of neutrons at the LANSCE/WNR 60R 20-meter flight path, and the precision {gamma}-ray spectrometry of the Compton-suppressed Ge detector array GEANIE. The first focus of the measurements was on the {sup 239}Pu(n,2n) cross section, followed by a series of other experiments on nuclei throughout the periodic table, with an emphasis on neutron-fluence activation detectors (or 'RadChem detectors'). Representative measurements will be presented, along with the techniques. Experiments in progress and future plans are mentioned.

  10. Neutron-Induced Reactions and Spectroscopy with GEANIE

    SciTech Connect

    Becker, J.A.; Nelson, R.O.

    2005-05-24

    A large number of partial {gamma}-ray cross sections produced in neutron-induced reactions with neutrons in the energy range 1 < En (MeV) < 200 have been measured over the past eight years. Partial {gamma}-ray cross sections are measured as a function of incident neutron energy using the time-of-flight technique. Reaction channel cross sections were deduced from these measurements with the aid of nuclear modeling. Enabling facilities are the intense 'white' source of neutrons at the LANSCE/WNR 60R 20-meter flight path, and the precision {gamma}-ray spectrometry of the Compton-suppressed Ge detector array GEANIE. The first focus of the measurements was on the 239Pu(n,2n) cross section, followed by a series of other experiments on nuclei throughout the periodic table, with an emphasis on neutron-fluence activation detectors (or 'RadChem detectors'). Representative measurements will be presented, along with the techniques. Experiments in progress and future plans are mentioned.

  11. 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.

  12. Chemistry and rotational excitation of O_2 in interstellar clouds. II. The 16O^18O isotopomer

    NASA Astrophysics Data System (ADS)

    Marechal, P.; Viala, Y. P.; Pagani, L.

    1997-12-01

    Although molecular oxygen O_2 is predicted to be an important constituent of the interstellar gas, it has not yet been observed in Galactic interstellar clouds. While ongoing O_2 observation projects in our Galaxy have to use stratospheric balloons or satellites, several teams have already tried to observe its isotopomer (16) O(18) O with ground-based telescopes. In this paper, a chemical model of interstellar clouds including (18) O and (13) C isotopic reactions with a non-LTE calculation of (16) O(18) O rotational population has been used to predict the intensity of the 3 (16) O(18) O lines observable from the ground, namely the 234, 298 and 402 GHz lines. These predictions are compared to the upper limits obtained by Marechal et al. (1997a) and to the tentative detection obtained by Pagani et al. (1993) towards L134N. We show that only the 234 GHz line is observable with today's receivers and that the strong upper limits we have reported are not compatible with a standard steady-state model. Clumpiness, high (0.7) C/O ratio or other non-standard models are required to explain our observations. The consequence of the (18) O isotopic fractionation is also discussed. The Table 4 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html

  13. New calculations of cyclotron production cross sections of some positron emitting radioisotopes in proton induced reactions

    NASA Astrophysics Data System (ADS)

    Tel, E.; Aydin, E. G.; Kaplan, A.; Aydin, A.

    2009-02-01

    In this study, new calculations on the excitation functions of 13C( p,n)13N, 14N( p,a)11C, 15N( p,n)15O, 16O( p,a)13N, 18O( p,n)18F, 62Ni( p,n)62Cu, 68Zn( p,n)68Ga and 72Ge( p,n)72 As reactions have been carried out in the 5-40 MeV incident proton energy range. In these calculations, the pre-equilibrium and equilibrium effects have been investigated. The pre-equilibrium calculations involve hybrid model, geometry dependent hybrid model, the cascade exciton model and full exciton model. Equilibrium effects were calculated according to Weisskopf-Ewing model. The calculated results have been compared with experimental data taken from literature.

  14. 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.

  15. Theoretical modeling of hydroxyl-radical-induced lipid peroxidation reactions.

    PubMed

    Tejero, Ismael; Gonzalez-Lafont, Angels; Lluch, José M; Eriksson, Leif A

    2007-05-24

    The OH-radical-induced mechanism of lipid peroxidation, involving hydrogen abstraction followed by O2 addition, is explored using the kinetically corrected hybrid density functional MPWB1K in conjunction with the MG3S basis set and a polarized continuum model to mimic the membrane interior. Using a small nonadiene model of linoleic acid, it is found that hydrogen abstraction preferentially occurs at the mono-allylic methylene groups at the ends of the conjugated segment rather than at the central bis-allylic carbon, in disagreement with experimental data. Using a full linoleic acid, however, abstraction is correctly predicted to occur at the central carbon, giving a pentadienyl radical. The Gibbs free energy for abstraction at the central C11 is approximately 8 kcal/mol, compared to 9 kcal/mol at the end points (giving an allyl radical). Subsequent oxygen addition will occur at one of the terminal atoms of the pentadienyl radical fragment, giving a localized peroxy radical and a conjugated butadiene fragment, but is associated with rather high free energy barriers and low exergonicity at the CPCM-MPWB1K/MG3S level. The ZPE-corrected potential energy surfaces obtained without solvent effects, on the other hand, display considerably lower barriers and more exergonic reactions.

  16. 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.

  17. [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.

  18. 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.

  19. The GILL study: glycerin-induced local reactions in immunotherapy.

    PubMed

    Calabria, Christopher W; Coop, Christopher A; Tankersley, Michael S

    2008-01-01

    The mechanism of local reactions is not well defined. Glycerin, an excellent preservative used commonly in immunotherapy extracts, is a recognized irritant. This study was undertaken to examine whether higher glycerin concentration in immunotherapy extracts is associated with an increase in local reaction rates during immunotherapy. A retrospective analysis of electronic immunotherapy records over a 12-month period was performed from a single site. A small local reaction was defined as induration and/or erythema at the injection site smaller than or equal to the size of the patient's palm. A large local reaction was defined as a reaction larger than the patient's palm. Over the 12-month period, 360 patients received a total of 9678 immunotherapy injections. For all injections, the total local reaction rate was 16.3% (1574/9678), the small local reaction rate was 15.9% (1536/9678), and the large local reaction rate was 0.4% (38/9678). For aeroallergens, small local reaction rates increased significantly with increasing allergen concentrations, from 7.3% (1:1000 vol/vol) to 23.0% (1:1 vol/vol; P < .001). The small local reaction rate was higher with increasing allergen content but not higher glycerin concentration. Large local reactions were infrequent and did not significantly increase with allergen or glycerin concentration. Small local, but not large local, reaction rates increase with higher allergen concentration, number, and volume. Higher glycerin concentrations (even 50%) are not associated with significantly higher small or large local reaction rates.

  20. 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.

  1. 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.

  2. 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.

  3. Syntheses of Anthracyclines and Fredericamycin A via Strong Base-Induced Cycloaddition Reaction of Homophthalic Anhydrides

    NASA Astrophysics Data System (ADS)

    Kita, Yasuyuki; Fujioka, Hiromichi

    Strong base-induced cycloaddition reactions of homophthalic anhydrides with quinone derivatives afford peri-hydroxyl aromatic compounds in a regioselective manner. The reactions have been applied to the syntheses of biologically important natural products. This review focuses on the following topics: (i) preparation of homophthalic anhydrides from homophthalic acids using (trimethylsilyl)ethoxyacetylene, (ii) strong base-induced cycloaddition of homophthalic anhydrides with the carbon-carbon double bond and the reaction mechanism, especially addressing the regiochemistry of the reaction, and (iii) application of the reaction to the efficient asymmetric syntheses of anthracyclines and fredericamycin A.

  4. 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.

  5. Nitrofurantoin-induced acute, subacute and chronic pulmonary reactions.

    PubMed

    Sovijärvi, A R; Lemola, M; Stenius, B; Idänpään-Heikkilä, J

    1977-01-01

    The clinical histories of 81 patients with hypersensitivity reactions to nitrofurantoin, 66 of whom had pulmonary reactions, were studied. Of all patients, 94% were women and of these, 43% were between 40 and 59 years of age. The nitrofurantoin preparation that contained vitamin c caused significantly fewer hypersensitivity reactions than the others. Acute pulmonary reactions appeared a mean of 8.7 days after the start of nitrofurantoin treatment. Typical for these were high fever, dyspnoea, cough, blood eosinophilia, bilateral pneumonic or pleuro-pneumonic infiltrations, a reduced transfer factor of the lung and, as revealed in pulmonary biopsy specimens, vasculitis, interstitial inflammation and alveolar exudation. Symptoms of subacute and chronic pulmonary reactions developed after at least 1 and 6 months of treatment, respectively. Findings of interest were anti-nuclear antibodies in serum, capillary sclerosis, interstitial fibrosis and inflammation in pulmonary tissue. Most patients with an acute pulmonary reaction recovered within 15 days, but in more than half of those with chronic reactions slight signs of pulmonary fibrosis persisted on follow-up. The findings suggest that the interstitial pulmonary changes caused by nitrofurantoin are largely the result of an Arthus-type immune complex-mediated reaction.

  6. [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.

  7. 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.

  8. Severe infusion reaction induced by trastuzumab: a case report.

    PubMed

    Tada, Keiichiro; Ito, Yoshinori; Hatake, Kiyohiko; Okudaira, Taeko; Watanabe, Jun-ichiro; Arakawa, Masahiro; Miyazato, Masayo; Irie, Tetsuya; Mizunuma, Nobuyuki; Takahashi, Syunji; Aiba, Keisuke; Horikoshi, Noboru; Kasumi, Fujio

    2003-01-01

    We report a case of a severe infusion reaction caused by trastuzumab. A 59-year-old woman with metastatic breast cancer was treated with trastuzumab. During the first infusion, initial symptoms such as severe headache and general fatigue developed. Blood pressure fell 90 minutes after these initial symptoms. A collapsed lung was demonstrated by chest X-ray and computed tomography. Steroid therapy was successfully used for these reactions. Careful monitoring of vital signs, examination of the respiratory system, and the use of steroids are recommended for severe infusion reaction.

  9. Ciprofloxacin induced bullous fixed drug reaction: three case reports

    PubMed Central

    Nair, Pragya A.

    2015-01-01

    Cutaneous adverse drug reactions (ADRs) are seen in about 1–2% cases. Fixed drug reaction (FDR) is responsible for about 10% of all ADRs. It is a delayed type of hypersensitivity reaction that occurs as lesions recurs at the same skin site due to repeated intake of an offending drug. The most common drugs causing fixed drug eruption (FDE) are analgesics, antibiotics, muscle relaxants and anticonvulsants. FDE due to ciprofloxacin has been reported earlier also, but bullous variant of FDR is rare. We hereby report three case reports of bullous FDR caused due to ciprofloxacin. PMID:25949980

  10. Varenicline-induced acute dystonic reaction: a case report.

    PubMed

    Uca, Ali Ulvi; Kozak, Hasan Hüseyin; Uguz, Faruk

    2014-01-01

    Dystonia is a syndrome characterized by sustained muscle contractions frequently causing twisting and repetitive movements or abnormal postures. Dystonic reactions may be a complication of many drugs such as antipsychotics, anti-emetics and antidepressants. This report presents a 25-year-old patient who was admitted to an emergency department with acute dystonia following the use of varenicline, a pharmacological agent used for the treatment of nicotine addiction. Dystonic reactions may be related to the dopaminergic deficiency caused by the use of varenicline. In conclusion, this report suggests that varenicline can cause dystonic reaction in at least some patients. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. 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.

  12. Importance of airway inflammation for late asthmatic reactions induced by toluene diisocyanate in sensitized subjects.

    PubMed

    Boschetto, P; Zocca, E; Bruchi, O; Cappellazzo, G; Milani, G F; Pivirotto, F; Mapp, C E; Fabbri, L M

    1987-01-01

    To determine the importance of airway inflammation for late asthmatic reactions and increased airway responsiveness induced by TDI, we investigated whether late asthmatic reactions and increased responsiveness induced by TDI are associated with airway inflammation and whether steroids prevent them by modifying the inflammatory response within the airways. We measured FEV1 before and at regular intervals after exposure to TDI and performed dose-response curves to methacholine and bronchoalveolar lavage 8 hr after TDI in two subjects with previously documented late asthmatic reaction; then we repeated the same procedure a few weeks after treatment with steroids. Airway responsiveness and polymorphonuclear cells were increased in both subjects after the late asthmatic reaction; treatment with steroids prevented late asthmatic reaction and the increase in airway responsiveness and polymorphonuclear cells in bronchoalveolar lavage. These results suggest that late asthmatic reaction induced by TDI may be caused by airway inflammation.

  13. 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.

  14. 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

  15. 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.

  16. [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.

  17. Metoclopramide induced acute dystonic reaction: a case report.

    PubMed

    Tianyi, Frank-Leonel; Agbor, Valirie Ndip; Njim, Tsi

    2017-01-07

    Metoclopramide is a commonly used anti-emetic drug known to cause extrapyramidal symptoms as adverse effects, amongst which are dystonic reactions. These reactions are more frequent at high doses of metoclopramide, in female patients, children and adults less than 30 years of age. We hereby present the case of a 16 year old female who had dystonic reactions from metoclopramide, highlighting its unpredictable nature and the shortcomings of the management in resource-limited settings. A 16 year old female Muslim from the Extreme North of Cameroon with no significant past history, was treated for severe malaria and associated refractory vomiting using intravenous quinine and metoclopramide respectively. She developed dystonic reactions after being administered her second dose of metoclopramide. The drug was discontinued and she was administered 8 mg of chlorpheniramine by mouth. Her symptoms resolved after 4 h. She was discharged 2 days later with no further complaints. Metoclopramide causes dystonic reactions which are often unpredictable and is frequently prescribed by health providers. This creates an environment of anxiety for the patient and the caregiver, and can result in life threatening consequences. Patients on metoclopramide should be monitored closely to detect these reactions early, and health facilities should be equipped to cope with the adverse effects before administration.

  18. Development of a code system DEURACS for theoretical analysis and prediction of deuteron-induced reactions

    NASA Astrophysics Data System (ADS)

    Nakayama, Shinsuke; Kouno, Hiroshi; Watanabe, Yukinobu; Iwamoto, Osamu; Ye, Tao; Ogata, Kazuyuki

    2017-09-01

    We have developed an integrated code system dedicated for theoretical analysis and prediction of deuteron-induced reactions, which is called DEUteron-induced Reaction Analysis Code System (DEURACS). DEURACS consists of several calculation codes based on theoretical models to describe respective reaction mechanisms and it was successfully applied to (d,xp) and (d,xn) reactions. In the present work, the analysis of (d,xn) reactions is extended to higher incident energy up to nearly 100 MeV and also DEURACS is applied to (d,xd) reactions at 80 and 100 MeV. The DEURACS calculations reproduce the experimental double-differential cross sections for the (d,xn) and (d,xd) reactions well.

  19. 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.

  20. 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.

  1. 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.

  2. Hydrodynamic fingering instability induced by a precipitation reaction.

    PubMed

    Nagatsu, Y; Ishii, Y; Tada, Y; De Wit, A

    2014-07-11

    We experimentally demonstrate that a precipitation reaction at the miscible interface between two reactive solutions can trigger a hydrodynamic instability due to the buildup of a locally adverse mobility gradient related to a decrease in permeability. The precipitate results from an A+B→C type of reaction when a solution containing one of the reactants is injected into a solution of the other reactant in a porous medium or a Hele-Shaw cell. Fingerlike precipitation patterns are observed upon displacement, the properties of which depend on whether A displaces B or vice versa. A mathematical modeling of the underlying mobility profile confirms that the instability originates from a local decrease in mobility driven by the localized precipitation. Nonlinear simulations of the related reaction-diffusion-convection model reproduce the properties of the instability observed experimentally. In particular, the simulations suggest that differences in diffusivity between A and B may contribute to the asymmetric characteristics of the fingering precipitation patterns.

  3. 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.

  4. (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.

  5. Anaphylactic reaction induced by Toxoplasma gondii-derived heat shock protein 70.

    PubMed

    Fang, Hao; Aosai, Fumie; Mun, Hye-Seong; Norose, Kazumi; Ahmed, Azza Kamal; Furuya, Mitsuko; Yano, Akihiko

    2006-10-01

    Toxoplasma gondii-derived heat shock protein 70 (T.g.HSP70) is a virulent molecule specific for tachyzoites of T. gondii. The expression of T.g.HSP70 rapidly increases just before death of the host, indicating that T.g.HSP70 functions as a danger signal during lethal acute T. gondii infection. In the present study, T.g.HSP70 was proven to be capable of inducing lethal anaphylactic reaction in T. gondii-infected wild-type (WT) mice. Anaphylactic reaction appeared within the first hour after intraperitoneal injection of T.g.HSP70 and was characterized by a series of consequent symptoms until death. T.g.HSP70-induced anaphylactic reaction was not observed in IFN-gamma knockout (GKO) mice, indicating the involvement of IFN-gamma in the reaction. The anaphylactic reaction was transferable to GKO mice by splenocytes but not serum from infected WT mice. Also, this reaction occurred in B cell-deficient mice, indicating that T.g.HSP70-induced anaphylactic reaction occurred through an Ig-independent pathway. The messenger RNA (mRNA) expression of IFN-gamma increased significantly in splenocytes from T. gondii-infected WT mice after T.g.HSP70 injection. Furthermore, the mRNA expression of platelet-activating factor (PAF) acetylhydrolase in WT, but not GKO mice, distinctly increased during the occurrence of T.g.HSP70-induced anaphylactic reaction, indicating the involvement of PAF in T.g.HSP70-induced anaphylactic reaction. Treatment with PAF receptor antagonist rescued WT mice from the anaphylactic reaction. These data demonstrated the involvement of IFN-gamma-dependent PAF activation in T.g.HSP70-induced anaphylactic reaction.

  6. 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

  7. Light induced electron transfer reactions of metal complexes

    SciTech Connect

    Sutin, N; Creutz, C

    1980-01-01

    Properties of the excited states of tris(2,2'-bipyridine) and tris(1,10-phenanthroline) complexes of chromium(III), iron(II), ruthenium(II), osmium(II), rhodium(III), and iridium(III) are described. The electron transfer reactions of the ground and excited states are discussed and interpreted in terms of the driving force for the reaction and the distortions of the excited states relative to the corresponding ground states. General considerations relevant to the conversion of light into chemical energy are presented and progress in the use of polypyridine complexes to effect the light decomposition of water into hydrogen and oxygen is reviewed.

  8. Decomposition of nuclear response functions for neutrino-induced reactions on 12C

    NASA Astrophysics Data System (ADS)

    Kim, Byungjick; Kim, K. S.; Kim, Hungchong; So, W. Y.; Cheoun, Myung-Ki

    2014-10-01

    We investigate the nuclear response functions in neutrino-induced reaction via a neutral current (NC) on 12C, which functions are comprised of Coulomb, longitudinal, magnetic and electric transitions. Those response functions in the NC reaction are closely related to those extracted from other types of NC reactions by electrons, protons and other light nuclei, such as A( e, e')A *, A( p, p')A *, A( d, d')A *, and A(6Li,6Li')A *. For example, the magnetic response function for the J π = 1+ state (M1) which is associated with the spin transfer reaction can be measured in inelastic scattering and may give us valuable information for the NC neutrino-induced reaction. Therefore, if we exploit response functions deduced by using other nuclear reactions, neutrino reactions could be estimated indirectly without relying on neutrino-induced reaction experiments. For the purpose, in this work, we decompose every response function in the neutrino reaction 12C( ν e , ν' e )12C*( J π = 1+) and address the role of each response function in the reaction.

  9. Endothelium-independent vasorelaxation effects of 16-O-acetyldihydroisosteviol on isolated rat thoracic aorta.

    PubMed

    Pantan, Rungusa; Onsa-Ard, Amnart; Tocharus, Jiraporn; Wonganan, Orawan; Suksamrarn, Apichart; Tocharus, Chainarong

    2014-10-22

    The aim of this study is to investigate the vasorelaxant effect of 16-O-acetyldihydroisosteviol (ADIS) and its underlying mechanisms in isolated rat aorta. Rat aortic rings were isolated, suspended in organ baths containing Kreb's solution, maintained at 37°C, and mounted on tungsten wire and continuously bubbled with a mixture of 95% O2 and 5% CO2 under a resting tension of 1g. The vasorelaxant effects of ADIS were investigated by means of isometric tension recording experiment. ADIS (0.1μM-3mM) induced relaxation of aortic rings pre-contracted by phenylephrine (PE, 10μM) and KCl (80mM) with intact-endothelium (Emax=79.26±3.74 and 79.88±3.79, respectively) or denuded-endothelium (Emax=88.05±3.69 and 78.22±6.86, respectively). In depolarization Ca(2+)-free solution, ADIS inhibits calcium chloride (CaCl2)-induced contraction in endothelium-denuded rings in a concentration-dependent manner. In addition, ADIS attenuates transient contractions in Ca(2+)-free medium containing EGTA (1mM) induced by PE (10μM) and caffeine (20mM). By contrast, relaxation was not affected by tetraethylammonium (TEA, 5mM), 4-aminopyridine (4-AP, 1mM), glibenclamide (10μM), barium chloride (BaCl2, 1mM), and 1H-[1,2,3]oxadiazolo[4,3-α]quinoxalin-1-one (ODQ, 1μM). These findings reveal the vasorelaxant effect of ADIS, through endothelium-independent pathway. It acts as a Ca(2+) channel blocker through both intracellular and extracellular Ca(2+) release. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Relativistic Approach to One Nucleon Knockout Reactions

    NASA Astrophysics Data System (ADS)

    Meucci, Andrea; Giusti, Carlotta; Pacati, Franco Davide

    2003-04-01

    We develop a fully relativistic distorted wave impulse approximation model for electron- and photon-induced one proton knockout reactions. The relativistic mean field for the bound state and the Pauli reduction for the scattering state are used, including a fully relativistic electromagnetic current operator. Results for 16O(e, e'p) cross section and structure functions are shown in various kinematic conditions and compared with nonrelativistic calculations. Nuclear transparency calculations in a Q2 range between 0.3 and 1.8 (GeV/c)2 are presented. Results for 16O(γ,p) differential cross sections are displayed in an energy range between 60 and 150 MeV including two-body seagull contribution in the nuclear current.

  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. 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.

  13. 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

  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. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Cardiopulmonary arrest induced by anaphylactoid reaction with contrast media.

    PubMed

    Nakamura, Iwao; Hori, Shingo; Funabiki, Tomohiro; Sekine, Kazuhiko; Kimura, Hiroyuki; Fujishima, Seitaro; Aoki, Katsunori; Kuribayashi, Sachio; Aikawa, Naoki

    2002-05-01

    Anaphylactoid reactions to iodinated contrast media can cause life-threatening events and even death. A 44-year-old woman presented with cardiopulmonary arrest (CPA) immediately following the administration of nonionic iodinated contrast media for an intravenous pyelography. Her cardiac rhythm during CPA was asystole. She was successfully resuscitated by the radiologists supported by paged emergency physicians using the prompt intravenous administration of 1 mg of epinephrine. Neither laryngeal edema nor bronchial spasm was observed during the course of treatment, and she was discharged on the 4th day without any complications. The patient did not have a history of allergy, but had experienced a myocardial infarction and aortitis. She had undergone 11 angiographies and had been taking a beta-adrenergic receptor antagonist. Planned emergency medical backup is advisable to ensure resuscitation in the event of an anaphylactoid reaction to the use of contrast media in-hospital settings.

  1. 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.

  2. 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

  3. Robotic reactions: Delay-induced patterns in autonomous vehicle systems

    NASA Astrophysics Data System (ADS)

    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.

  4. 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.

  5. Electron induced reactions in condensed mixtures of methane and ammonia.

    PubMed

    Kundu, Sramana; Prabhudesai, Vaibhav S; Krishnakumar, E

    2017-09-27

    We demonstrate the efficient formation of carbon-nitrogen bonds starting from CH4 and NH3 on a metal surface at cryogenic temperatures. Electrons in the energy range of 1-90 eV are used to initiate chemical reactions in mixed molecular films of CH4 and NH3 at ∼15 K, and the products are detected by performing temperature programmed desorption (TPD). Extensive dehydrogenation occurs at all energies giving the products CH2NH and HCN in preference to CH3NH2. This is likely to do with the energetics of the reactions and the subsequent stability of these species in the condensed film. Thermal processing of the irradiated mixture favours dehydrogenation as indicated by the results of using different desorption rates. Electron impact excitation and subsequent dissociation into radicals is the reaction-initiating step rather than ionization of CH4 and NH3, as inferred from the yield of products as a function of electron energy. This could give insight into the important catalytic process of the industrial scale synthesis of HCN from CH4 and NH3 over Pt. This may also be a relevant pathway in the astrochemical environment where CN and HCN are abundant and low-energy electrons are found ubiquitously.

  6. Reconstruction of ^16O(,)^12C Events in the HIγS Optical Readout Time Projection Chamber

    NASA Astrophysics Data System (ADS)

    Stave, S.; Ahmed, M. W.; Clinton, E. R.; Howell, C. R.; Seo, P.-N.; Weller, H. R.; Gai, M.; Young, A. H.; Bromberger, B.; Dangendorf, V.; Tittelmeier, K.

    2008-10-01

    A new optical readout time projection chamber (O-TPC) is in use at the High Intensity γ-ray Source (HIγS) located at the Free Electron Laser Laboratory on the Duke University campus. One application of the HIγS O-TPC is the study of the inverse of the ^12C(,)^16O reaction which is important for stellar evolution theory. In the O-TPC, incoming γ-rays interact with an ^16O nucleus producing an α and a ^12C which then leave trails of ionization electrons along their path. The O-TPC then provides several signals each of which must be interpreted simultaneously to determine the different particle types, their energies and their directions. Part of the challenge of operating the O-TPC is integrating the fast signals from the photomultiplier tubes and drift chamber with the slow signals from the CCD camera which images the tracks. Automated routines have been developed to take all of the available track information and provide a reliable determination of the interaction cross section. Examples of the method and preliminary results will be presented.

  7. 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.

  8. Reaction-induced grain boundary cracking and anisotropic fluid flow during prograde devolatilization reactions within subduction zones

    NASA Astrophysics Data System (ADS)

    Okamoto, Atsushi; Shimizu, Hiroyuki; Fukuda, Jun-ichi; Muto, Jun; Okudaira, Takamoto

    2017-09-01

    Devolatilization reactions during prograde metamorphism are a key control on the fluid distribution within subduction zones. Garnets in Mn-rich quartz schist within the Sanbagawa metamorphic belt of Japan are characterized by skeletal structures containing abundant quartz inclusions. Each quartz inclusion was angular-shaped, and showed random crystallographic orientations, suggesting that these quartz inclusions were trapped via grain boundary cracking during garnet growth. Such skeletal garnet within the quartz schist formed related to decarbonation reactions with a positive total volume change (Δ V t > 0), whereas the euhedral garnet within the pelitic schists formed as a result of dehydration reaction with negative Δ V t values. Coupled hydrological-chemical-mechanical processes during metamorphic devolatilization reactions were investigated by a distinct element method (DEM) numerical simulation on a foliated rock that contained reactive minerals and non-reactive matrix minerals. Negative Δ V t reactions cause a decrease in fluid pressure and do not produce fractures within the matrix. In contrast, a fluid pressure increase by positive Δ V t reactions results in hydrofracturing of the matrix. This fracturing preferentially occurs along grain boundaries and causes episodic fluid pulses associated with the development of the fracture network. The precipitation of garnet within grain boundary fractures could explain the formation of the skeletal garnet. Our DEM model also suggests a strong influence of reaction-induced fracturing on anisotropic fluid flow, meaning that dominant fluid flow directions could easily change in response to changes in stress configuration and the magnitude of differential stress during prograde metamorphism within a subduction zone.

  9. Acute generalized exanthematous pustulosis: an enigmatic drug-induced reaction.

    PubMed

    Momin, Saira B; Del Rosso, James Q; Michaels, Brent; Mobini, Narciss

    2009-06-01

    Acute generalized exanthematous pustulosis (AGEP) is a diffuse pustular disorder that is primarily drug induced and characterized by acute, extensive, small, nonfollicular, sterile pustules that usually begin in intertriginous folds with widespread edema and erythema. This article reports a case in which thalidomide, dexamethasone, or meloxicam may have been the etiologic agent to induce AGEP and the skin condition may have worsened with administration of additional medications during hospital admission. A good thorough medical history, including a drug history, along with clinicopathologic correlation is extremely important in a patient presenting with acute diffuse pustular lesions.

  10. 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.

  11. 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.

  12. 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.

  13. 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.…

  14. 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

  15. 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

  16. Recurrence of drug-induced reactions in DRESS patients.

    PubMed

    Picard, D; Vellar, M; Janela, B; Roussel, A; Joly, P; Musette, P

    2015-04-01

    Drug reaction with eosinophilia and systemic symptoms (DRESS) may relapse following introduction of drugs structurally unrelated to the initial culprit drug. To assess the frequency and characteristics of recurrent drug eruptions in patients with history of DRESS. Patients who had developed adverse cutaneous reaction after DRESS occurrence were recruited from the regional database of Upper Normandy in France. Rate of recurrences were compared with patients with Toxic Epidermal Necrolysis (TEN) and Stevens-Johnson syndrome (SJS) patients during the same time frame. Of the 60 cases of DRESS collected, 15 (25%) with recurrences were retained for analysis. Seven patients had a single recurrence, whereas eight patients had several relapses. In the patients with pre-existing DRESS, recurrences were incomplete, corresponding to cutaneous rash in 13 cases and associated with eosinophilia in seven cases. Internal organ involvement was observed in two cases. In contrast, a single recurrence was found out of 61 patients with TEN/SJS. Incomplete recurrences with structurally unrelated culprit drugs are a frequent phenomenon in DRESS patients. © 2014 European Academy of Dermatology and Venereology.

  17. Does Observation of Postural Imbalance Induce a Postural Reaction?

    PubMed Central

    Tia, Banty; Saimpont, Arnaud; Paizis, Christos; Mourey, France; Fadiga, Luciano; Pozzo, Thierry

    2011-01-01

    Background Several studies bring evidence that action observation elicits contagious responses during social interactions. However automatic imitative tendencies are generally inhibited and it remains unclear in which conditions mere action observation triggers motor behaviours. In this study, we addressed the question of contagious postural responses when observing human imbalance. Methodology/Principal Findings We recorded participants' body sway while they observed a fixation cross (control condition), an upright point-light display of a gymnast balancing on a rope, and the same point-light display presented upside down. Our results showed that, when the upright stimulus was displayed prior to the inverted one, centre of pressure area and antero-posterior path length were significantly greater in the upright condition compared to the control and upside down conditions. Conclusions/Significance These results demonstrate a contagious postural reaction suggesting a partial inefficiency of inhibitory processes. Further, kinematic information was sufficient to trigger this reaction. The difference recorded between the upright and upside down conditions indicates that the contagion effect was dependent on the integration of gravity constraints by body kinematics. Interestingly, the postural response was sensitive to habituation, and seemed to disappear when the observer was previously shown an inverted display. The motor contagion recorded here is consistent with previous work showing vegetative output during observation of an effortful movement and could indicate that lower level control facilitates contagion effects. PMID:21423622

  18. Towards the core structure of Strychnos alkaloids using samarium diiodide-induced reactions of indole derivatives.

    PubMed

    Beemelmanns, Christine; Gross, Steffen; Reissig, Hans-Ulrich

    2013-12-23

    This report describes the development of a first and second generation approach towards the synthesis of the ABCEG pentacyclic core structure of Strychnos alkaloids. First, we discuss a sequential approach applying a series of functional group transformations to prepare suitable precursors for cyclization reactions. These include attempts of samarium diiodide-induced cyclizations or a Barbier-type reaction of a transient lithium organyl, which successfully led to a tetracyclic key building block earlier used for the synthesis of strychnine. Secondly, we account our first steps towards the development of an atom-economical samarium diiodide-induced cascade reaction using "dimeric" indolyl ketones as cyclization precursors. In this context, we discuss plausible mechanisms for the samarium diiodide-induced cascade reaction as well as transformations of the obtained tetracyclic dihydroindoline derivatives. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. SET-Induced Biaryl Cross-Coupling: An SRN1 Reaction

    PubMed Central

    2015-01-01

    The SET-induced biaryl cross-coupling reaction is established as the first example of a Grignard SRN1 reaction. The reaction is examined within the mechanistic framework of dissociative electron transfer in the presence of a Lewis acid. DFT calculations show that the reaction proceeds through a radical intermediate in the form of an Mg ion-radical cage, which eludes detection in trapping experiments by reacting quickly to form an MgPh2 radical anion intermediate. A new mechanism is proposed. PMID:24564385

  20. Interdiffusion and reaction of metals: The influence and relaxation of mismatch-induced stress

    NASA Astrophysics Data System (ADS)

    Hartung, F.; Schmitz, G.

    2001-12-01

    The early interdiffusion stages in epitaxially grown Ag/Au and Cu/Au reaction couples are investigated by high-resolution and Z-contrast electron microscopy. While the interdiffusion in the lattice-matched system Ag/Au follows Fick's diffusion laws from the very beginning, a complex two-stage reaction is observed in the lattice-mismatched Cu/Au samples. A fast diffusion at the beginning of the heat treatment produces a planar zone of lattice defects along the interface, which release most of the induced stress. This first reaction stage stops after reaching a diffusion length of about 15 nm. Subsequent interdiffusion takes place by a recrystallization mechanism comprising heterogeneous nucleation of new grains and diffusion-induced grain boundary migration. During this second reaction stage, discontinuous composition profiles are determined, evidencing stress release at high-angle grain boundaries. The recrystallization mechanism also dominates the formation of ordered intermetallics at lower reaction temperatures.

  1. [Photo-induced processes and reaction dynamics in bacteriorhodopsin].

    PubMed

    Terpugov, E L; Degtyareva, O V

    2015-01-01

    In this review we have focused on the advances madein observing the photo-induced response in bacteriorhodopsin and understanding the mechanisms of retinal-protein interactions which are still obscure. We discuss our recent data obtained on the wild type of bacteriorhodopsin and model compounds. This paper presents our new spectroscopic data on amino acids obtained using FT-IR emission spectroscopy. Based on the characteristics of the structure and optical properties of glycine and L-lysine that simulate a photo-induced behaviour of an opsin under natural conditions we tried to find an answer to one of the most important questions concerning the role of protein in the primary processes in bacteriorhodopsin.

  2. 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.

  3. 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.

  4. Lateral variations of radiobiological properties of therapeutic fields of (1)H, (4)He, (12)C and (16)O ions studied with Geant4 and microdosimetric kinetic model.

    PubMed

    Dewey, Sophie; Burigo, Lucas; Pshenichnov, Igor; Mishustin, Igor; Bleicher, Marcus

    2017-06-27

    As known, in cancer therapy with ion beams the relative biological effectiveness (RBE) of ions changes in the course of their propagation in tissues. Such changes are caused not only by increasing the linear energy transfer (LET) of beam particles with the penetration depth towards the Bragg peak, but also by nuclear reactions induced by beam nuclei leading to the production of various secondary particles. Although the changes of RBE along the beam axis have been studied quite well, much less attention has been paid to the evolution of RBE in the transverse direction, perpendicular to the beam axis. In order to fill this gap, we simulated radiation fields of (1)H, (4)He, (12)C and (16)O nuclei of 20 mm in diameter by means of a Geant4-based Monte Carlo model for heavy-ion therapy connected with the modified microdosimetric kinetic model to describe the response of normal ([Formula: see text] Gy) and early-responding ([Formula: see text] Gy) tissues. Depth and radial distributions of saturation-corrected dose-mean lineal energy, RBE and RBE-weighted dose are investigated for passive beam shaping and active beam scanning. The field of (4)He has a small lateral spread as compared with (1)H field, and it is characterised by a modest lateral variation of RBE suggesting the use of fixed RBE values across the field transverse cross section at each depth. Reduced uncertainties of RBE on the boundary of a (4)He treatment field can be advantageous in a specific case of an organ at risk located in lateral proximity to the target volume. It is found that the lateral distributions of RBE calculated for (12)C and (16)O fields demonstrate fast variations in the radial direction due to changes of dose and composition of secondary fragments in the field penumbra. Nevertheless, the radiation fields of all four projectiles at radii larger than 20 mm can be characterized by a common RBE value defined by tissue radiosensitivity. These findings can help, in particular, in accessing

  5. Lateral variations of radiobiological properties of therapeutic fields of 1H, 4He, 12C and 16O ions studied with Geant4 and microdosimetric kinetic model

    NASA Astrophysics Data System (ADS)

    Dewey, Sophie; Burigo, Lucas; Pshenichnov, Igor; Mishustin, Igor; Bleicher, Marcus

    2017-07-01

    As known, in cancer therapy with ion beams the relative biological effectiveness (RBE) of ions changes in the course of their propagation in tissues. Such changes are caused not only by increasing the linear energy transfer (LET) of beam particles with the penetration depth towards the Bragg peak, but also by nuclear reactions induced by beam nuclei leading to the production of various secondary particles. Although the changes of RBE along the beam axis have been studied quite well, much less attention has been paid to the evolution of RBE in the transverse direction, perpendicular to the beam axis. In order to fill this gap, we simulated radiation fields of 1H, 4He, 12C and 16O nuclei of 20 mm in diameter by means of a Geant4-based Monte Carlo model for heavy-ion therapy connected with the modified microdosimetric kinetic model to describe the response of normal ((α/β)_x-rays=3.8 Gy) and early-responding ((α/β)_x-rays=10 Gy) tissues. Depth and radial distributions of saturation-corrected dose-mean lineal energy, RBE and RBE-weighted dose are investigated for passive beam shaping and active beam scanning. The field of 4He has a small lateral spread as compared with 1H field, and it is characterised by a modest lateral variation of RBE suggesting the use of fixed RBE values across the field transverse cross section at each depth. Reduced uncertainties of RBE on the boundary of a 4He treatment field can be advantageous in a specific case of an organ at risk located in lateral proximity to the target volume. It is found that the lateral distributions of RBE calculated for 12C and 16O fields demonstrate fast variations in the radial direction due to changes of dose and composition of secondary fragments in the field penumbra. Nevertheless, the radiation fields of all four projectiles at radii larger than 20 mm can be characterized by a common RBE value defined by tissue radiosensitivity. These findings can help, in particular, in accessing the transverse

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Reactions induced by beams of neutron and proton halo nuclei

    NASA Astrophysics Data System (ADS)

    Penionzhkevich, Yu. E.

    1997-02-01

    Within the collaboration Dubna-GANIL (Caen, France) - IPN (Orsay, France) - NPI (Rez, Czech Republic) - IAP (Bucharest, Romania) at GANIL and the Dubna U400M accelerator, experiments have been carried out to study elastic scattering, fusion and fission using secondary ion beams of 6He, 11Li and 8B. The fission cross-section for the 6He isotopes has been found to be significantly higher than for the 4He nuclei. This enhancement depends mainly on the entrance channel and it is connected with the neutron skin of the 6He nuclei. Also, investigation of the elastic scattering of 11Li (neutron halo), 7Be and 8B (proton halo) has been performed. The microscopic analysis supports the existence of a neutron halo in 11Li and the proton skin in 8B and 7Be. Perspectives for investigations in this field at the Laboratory of Nuclear Reactions JINR are also discussed.

  12. Differential Enzymatic 16O/18O Labelling for the Detection of Cross-Linked Nucleic Acid-Protein Heteroconjugates.

    PubMed

    Flett, Fiona J; Sachsenberg, Timo; Kohlbacher, Oliver; Mackay, C Logan; Interthal, Heidrun

    2017-09-08

    Cross-linking of nucleic acids to proteins in combination with mass spectrometry permits the precise identification of interacting residues between nucleic acid-protein complexes. However, the mass spectrometric identification and characterisation of cross-linked nucleic acid-protein heteroconjugates within a complex sample is challenging. Here we establish a novel enzymatic differential 16O/18O labelling approach, which uniquely labels heteroconjugates. We have developed an automated data analysis workflow based on OpenMS for the identification of differentially isotopically labelled heteroconjugates against a complex background. We validated our method using synthetic model DNA oligonucleotide-peptide heteroconjugates which were subjected to the labelling reaction and analysed by high resolution FT-ICR mass spectrometry.

  13. Alpha clustering and nuclear molecules in8Be, 12C, 16O, 20Ne, 24Mg, and32S

    NASA Astrophysics Data System (ADS)

    Royer, G.; Eudes, P.

    2017-06-01

    Within a liquid drop model the energy of the12C,16O,20Ne,24Mg and32S 4n-nuclei has been calculated within different configurations of α-molecules : linear chain, triangle, square, tetrahedron, pentagon, trigonal bipyramid, square pyramid, hexagon, octahedron, octagon and cube. The potential barriers governing the decay and entrance channels via α emission or absorption as well as the potential barriers of other possible binary and ternary reactions have been compared. The rms radii of the linear chains do not correspond to the experimental rms radii of the ground states. The binding energies of the three-dimensional molecules at the nascent point of the fragments are higher than the ones of the planar configurations. The A-4 daughter plus α particle configurations have always the lowest potential energy.

  14. 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.

  15. 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.

  16. 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. © 2016 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Ostracod calcite records the 18O/16O ratio of the bicarbonate and carbonate ions in water

    NASA Astrophysics Data System (ADS)

    Devriendt, Laurent S.; McGregor, Helen V.; Chivas, Allan R.

    2017-10-01

    ], Candonids δ18O decreases by -0.098 ± 0.024‰, Cyprids by -0.075 ± 0.004‰, Cytherids by -0.057 ± 0.012‰, and Limnocytherids by -0.058 ± 0.005‰. (4) The similarity in 18O/16O between ostracod calcite and the sum of host water 'HCO3- and CO32-' (despite species-specific offsets) suggests rapid precipitation of a finite DIC pool in the ostracod calcifying fluid. We propose an ostracod δ18O model whereby the more negative the 18O/16O of a given species relative to the sum of CO32- and HCO3-, the greater the isotopic equilibrium between the DIC pool and H2O in the ostracod calcifying fluid. (5) Higher host water salinities and pH induce higher [CO32-]/[DIC], resulting in lower ostracod δ18O, which explains the variable salinity and pH effects on ostracod δ18O. Our database and ostracod δ18O model shows that ostracod δ18O records from closed basin environments likely reflect high or variable [CO32-]/[DIC], rather than water temperature and δ18O alone. Our study reconciles contradictory observations of controls on ostracod δ18O and paves the way for improved paleo-environmental interpretations and reconstructions of past water [CO32-]/[DIC].

  18. 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.

  19. Prednisone inhibits late asthmatic reactions and airway inflammation induced by toluene diisocyanate in sensitized subjects.

    PubMed

    Boschetto, P; Fabbri, L M; Zocca, E; Milani, G; Pivirotto, F; Dal Vecchio, A; Plebani, M; Mapp, C E

    1987-09-01

    To determine the importance of airway inflammation for late asthmatic reactions induced by toluene diisocyanate (TDI), we investigated whether prednisone prevented them [corrected] by modifying the associated airway inflammatory reaction. We measured FEV1 before and at regular intervals after exposure to TDI and performed bronchoalveolar lavage at 8 hours after TDI in two groups of subjects with previously documented late asthmatic reactions, in one group, after no treatment, and in the other group, after treatment with prednisone (50 mg/day for 4 days). After no treatment, each subject developed a late asthmatic reaction, an increase in airway responsiveness, polymorphonuclear leukocytosis, and increased albumin in bronchoalveolar lavage. By contrast, after treatment with prednisone, no subject developed a late asthmatic reaction or an increase in airway responsiveness, and the number of leukocytes and the concentration of albumin were normal in bronchoalveolar lavage. These results suggest that late asthmatic reactions induced by TDI may be caused by airway inflammation and that prednisone may block them [corrected] by inhibiting the inflammatory reaction of the airway induced by TDI in sensitized subjects.

  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. 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.

  3. 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)

  4. 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/.

  5. An egg envelope component induces the acrosome reaction in sturgeon sperm.

    PubMed

    Cherr, G N; Clark, W H

    1985-04-01

    The acrosome reaction in Acipenser transmontanus sperm can be induced by a 66,000 dalton glycoprotein that is present in Layer 3 (L3) of the egg envelope and in egg water only following exposure of the eggs to fresh water. When egg water is fractionated on Sepharose CL 6B, the 66,000 dalton glycoprotein-containing fractions possess acrosome reaction inducing activity. Egg water may be species-specific in its ability to elicit the acrosome reaction, as demonstrated by the fact that it has no effect on the sperm of Acipenser fulvescens. Egg jelly possesses no acrosome reaction, inducing activity. The major carbohydrate-containing component of the egg envelope is L3, a layer that contains galactose residues. L3 possesses a 70,000 dalton glycoprotein prior to freshwater exposure and lacks the 66,000 dalton component. If isolated from polyacrylamide gels, the 70,000 dalton glycoprotein elicits acrosome reactions in what appears to be a species specific manner. After freshwater exposure, L3 contains both the 70,000 dalton glycoprotein and the 66,000 dalton glycoprotein that is also present in egg water. The appearance of the 66,000 dalton inducer can be blocked by the incubation of eggs in fresh water containing inhibitors of trypsin activity. Thus, the soluble inducer in egg water may be proteolytically derived from a higher molecular weight complex in the egg envelope.

  6. 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.

  7. [Cyanamide-ethanol reaction induced shock: report of a case and literature review].

    PubMed

    Kondo, Yutaka; Fuke, Chiaki; Higa, Ayumi; Kukita, Ichiro

    2013-12-01

    Cyanamide is a known alcohol deterrent, and it may cause severe cyanamide-ethanol reaction if a patient consumes high amounts of alcohol during treatment. We report a rare case of cyanamide-ethanol reaction-induced shock in a 73-year-old man who was taking cyanamide for the treatment of alcohol dependence. The patient complained of acute onset of dyspnea after drinking. On arrival, he was in a state of shock. We immediately started hydration and administered 0.3 mg adrenaline by intramuscular injection. However, the patient's general condition did not improve. We could rescue him only after a high dose of adrenaline was administered by continuous intravascular injection. In general, in the treatment of cyanamide-ethanol reaction-induced shock, adrenaline or noradrenaline should be used instead of dopamine. Some cases of severe cyanamide-ethanol reactions have been recently reported in Japan. We performed a literature review and have discussed these cases in the text.

  8. Surface chemical reactions induced by well-controlled molecular beams: translational energy and molecular orientation control.

    PubMed

    Okada, Michio

    2010-07-07

    I review our recent studies of chemical reactions on single-crystalline Cu and Si surfaces induced by hyperthermal oxygen molecular beams and by oriented molecular beams, respectively. Studies of oxide formation on Cu induced by hyperthermal molecular beams suggest that the translational energy of the incident molecules plays a significant role. The use of hyperthermal molecular beams enables us to open up new chemical reaction paths, and to develop new methods for the fabrication of thin films. Oriented molecular beams also demonstrate the possibility for controlling surface chemical reactions by varying the orientation of the incident molecules. The steric effects found on Si surfaces hint at new ways of achieving material fabrication on Si surfaces. Controlling the initial conditions of incoming molecules is a powerful tool for creating new materials on surfaces with well-controlled chemical reactions. © 2010 IOP Publishing Ltd

  9. 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.

  10. 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

  11. Self-Organization Induced by Self-Assembly in Microheterogeneous Reaction-Diffusion System.

    PubMed

    Cherkashin, Alexander A; Vanag, Vladimir K

    2017-03-09

    When acrylamide (AA) monomers are added to the Belousov-Zhabotinsky (BZ) reaction incorporated into nanodroplets of water-in-oil aerosol OT (AOT) microemulsion (the BZ-AOT system), free radicals produced in the BZ reaction initiate polymerization of AA monomers and polyacrylamide particles are formed. These particles change the microstructure of the AOT microemulsion thus inducing the transition from Turing patterns to new dissipative patterns which can be either stationary "black" spots or waves.

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Experimental excitation functions of deuteron induced reactions on natural thallium up to 50 MeV

    NASA Astrophysics Data System (ADS)

    Adam Rebeles, R.; Van den Winkel, P.; Hermanne, A.; Tárkányi, F.; Takács, S.

    2012-10-01

    Excitation functions of deuteron induced reactions on natural thallium leading to the formation of 204m,203m2+m1+g,202m,201m+g,200Pb and 202,201m+g,200m+gTl isotopes were determined up to 50 MeV. The cross sections were measured by an activation technique using stacked foil irradiation. The excitation functions of the investigated reactions are compared with data reported in literature and also with the theoretical results of TALYS nuclear reaction code. From the measured cross section data, the thick target yield for the medical interesting 203Pb isotope is calculated.

  2. 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.

  3. Flux and dose transmission through concrete of neutrons from proton induced reactions on various target elements

    NASA Astrophysics Data System (ADS)

    Maiti, Moumita; Nandy, Maitreyee; Roy, S. N.; Sarkar, P. K.

    2004-12-01

    Simple empirical expressions for transmission of flux and dose through concrete are presented for neutrons from proton induced reactions. For this purpose the neutron emission from different targets in proton induced reactions in the energy range 25-200 MeV have been considered. The calculated effective dose outside a concrete shield shows overall good agreement with the effective dose estimated from measured neutron flux in the framework of the Moyer model. The calculated effective attenuation length shows a rising trend with incident proton energy and shield thickness.

  4. Large-Amplitude Deformation and Bond Breakage in Shock-Induced Reactions of Explosive Molecules

    NASA Astrophysics Data System (ADS)

    Kay, Jeffrey

    The response of explosive molecules to large-amplitude mechanical deformation plays an important role in shock-induced reactions and the initiation of detonation in explosive materials. In this presentation, the response of a series of explosive molecules (nitromethane, 2,4,6-trinitrotoluene [TNT], and 2,4,6-triamino-1,3,5-trinitrobenzene [TATB]) to a variety of large-amplitude deformations are examined using ab initio quantum chemical calculations. Large-amplitude motions that result in bond breakage are described, and the insights these results provide into both previous experimental observations and previous theoretical predictions of shock-induced reactions are discussed.

  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. A possible role for cysteinyl-leukotrienes in non-ionic contrast media induced adverse reactions.

    PubMed

    Böhm, Ingrid; Speck, Ulrich; Schild, Hans

    2005-09-01

    To test whether mono- or dimeric X-ray contrast media (CM) may induce the de novo production of cysteinyl-leukotriens (cys-LT), that could contribute to allergic/allergy-like side effects. Leukocytes from 39 patients receiving iopromide or iotrolan for routine CT-examination were analyzed for the production of cys-LT. Histamine levels were analyzed in plasma specimens. One patient with a positive history of a previous CM-reaction did not receive CM-injection. Three patients of the iopromide and five of the iotrolan group showed adverse reactions. Reactors had increased cys-LT values in samples obtained before CM-injection induced by the positive control (anti-FcepsilonRI antibodies) (6763.7 pg/ml+/-1367.3 versus 2299.8 pg/ml+/-399.2; p<0.007). Patients with versus without CM-reaction did not differ significantly with respect to their histamine values before CM-administration. In vitro iopromide (p<0.0002) and iotrolan (p<0.0008) induced significant cys-LT production as compared to IL-3 stimulation. In vivo both CM induced a significant increase 6h after CM administration (p<0.05). Our findings suggest that both CM seem to induce cys-LT production. As to whether the observed increased values in pre-dose samples of patients with as compared to those without reactions could contribute to identify high risk patients should be investigated in larger patient groups in future.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Red light-induced redox reactions in cells observed with TEMPO.

    PubMed

    Eichler, Maor; Lavi, Ronit; Friedmann, Harry; Shainberg, Asher; Lubart, Rachel

    2007-06-01

    The aim of this study was to determine the wavelength dependence of light-induced redox reactions in cells, particularly whether there is any contribution by red wavelengths. An additional aim was to assess the potential of 2,2,6,6-tetramethyl piperidine-N-oxyl (TEMPO) as a tool for measuring these redox reactions. Visible light has been shown to affect cells, and redox reactions, which have been detected previously using spin traps, have been proposed as a mechanism. However, there is little evidence that red light, which is used in most such experiments, is redox active in cells. Redox activity was observed by measuring the decay of the electron paramagnetic resonance signal of TEMPO that occurs in the presence of illuminated cells. Color filters were used to generate blue, green, and red light, and the decay resulting from these wavelengths was compared to the decay caused by white light. Shorter wavelengths have a considerably stronger effect than longer wavelengths, although red light has some effect. Creation of reactive oxygen species by red light was confirmed with the spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). Red light can induce redox reactions in illuminated cells. However, shorter wavelengths are more efficient in this regard. In addition, TEMPO was found to be a more sensitive probe than DMPO for detecting light-induced cellular redox reactions.

  13. 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.

  14. Tailoring transition-metal hydroxides and oxides by photon-induced reactions

    SciTech Connect

    Niu, Kai -Yang; Fang, Liang; Ye, Rong; Nordlund, Dennis; Doeff, Marca M.; Lin, Feng; Zheng, Haimei

    2016-10-18

    Controlled synthesis of transition-metal hydroxides and oxides with earth-abundant elements have attracted significant interest because of their wide applications, for example as battery electrode materials or electrocatalysts for fuel generation. Here, we report the tuning of the structure of transition-metal hydroxides and oxides by controlling chemical reactions using an unfocused laser to irradiate the precursor solution. A Nd:YAG laser with wavelengths of 532 nm or 1064 nm was used. The Ni2+, Mn2+, and Co2+ ion-containing aqueous solution undergoes photo-induced reactions and produces hollow metal-oxide nanospheres (Ni0.18Mn0.45Co0.37Ox) or core–shell metal hydroxide nanoflowers ([Ni0.15Mn0.15Co0.7(OH)2](NO3)0.2•H2O), depending on the laser wavelengths. We propose two reaction pathways, either by photo-induced redox reaction or hydrolysis reaction, which are responsible for the formation of distinct nanostructures. As a result, the study of photon-induced materials growth shines light on the rational design of complex nanostructures with advanced functionalities.

  15. Tailoring transition-metal hydroxides and oxides by photon-induced reactions

    DOE PAGES

    Niu, Kai -Yang; Fang, Liang; Ye, Rong; ...

    2016-10-18

    Controlled synthesis of transition-metal hydroxides and oxides with earth-abundant elements have attracted significant interest because of their wide applications, for example as battery electrode materials or electrocatalysts for fuel generation. Here, we report the tuning of the structure of transition-metal hydroxides and oxides by controlling chemical reactions using an unfocused laser to irradiate the precursor solution. A Nd:YAG laser with wavelengths of 532 nm or 1064 nm was used. The Ni2+, Mn2+, and Co2+ ion-containing aqueous solution undergoes photo-induced reactions and produces hollow metal-oxide nanospheres (Ni0.18Mn0.45Co0.37Ox) or core–shell metal hydroxide nanoflowers ([Ni0.15Mn0.15Co0.7(OH)2](NO3)0.2•H2O), depending on the laser wavelengths. We propose twomore » reaction pathways, either by photo-induced redox reaction or hydrolysis reaction, which are responsible for the formation of distinct nanostructures. As a result, the study of photon-induced materials growth shines light on the rational design of complex nanostructures with advanced functionalities.« less

  16. Calculations of Proton Emission Cross Sections in Deuteron Induced Reactions of Some Fusion Structural Materials

    NASA Astrophysics Data System (ADS)

    Yiğit, M.; Tel, E.; Tanır, G.

    2013-06-01

    The growing demands for energy consumption have led to the increase of the research and development activities on new energy sources. Fusion energy has the highest potential to become a very safe, clean and abundant energy source for the future. To get energy from fusion are needed for development of fusion reactor technology. Particularly, the design and development of international facilities as International Thermonuclear Experimental Reactor and International Fusion Material Irradiation Facility requires for the cross-section data of deuteron induced reactions. Moreover, the selection of fusion structural materials are an indispensable component for this technology. Therefore, the cross-section data of deuteron induced reactions on fusion structural materials are of great importance for development of fusion reactor technology. In this study, reaction model calculations of the cross sections of deuteron induced reactions on structural fusion materials such as 27Al, 59Co, 55Mn, 50Cr, 54Cr, 64Ni, 109Ag, 184W and 186W have been carried out for incident energies up to 50 MeV. In these calculations, the pre-equilibrium and equilibrium effects for ( d, p) stripping reactions have been investigated. The pre-equilibrium calculations involve the new evaluated the geometry dependent hybrid model and hybrid model. Equilibrium effects are calculated according to the Weisskopf-Ewing 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 literature.

  17. Tailoring Transition-Metal Hydroxides and Oxides by Photon-Induced Reactions.

    PubMed

    Niu, Kai-Yang; Fang, Liang; Ye, Rong; Nordlund, Dennis; Doeff, Marca M; Lin, Feng; Zheng, Haimei

    2016-11-07

    Controlled synthesis of transition-metal hydroxides and oxides with earth-abundant elements have attracted significant interest because of their wide applications, for example as battery electrode materials or electrocatalysts for fuel generation. Here, we report the tuning of the structure of transition-metal hydroxides and oxides by controlling chemical reactions using an unfocused laser to irradiate the precursor solution. A Nd:YAG laser with wavelengths of 532 nm or 1064 nm was used. The Ni(2+) , Mn(2+) , and Co(2+) ion-containing aqueous solution undergoes photo-induced reactions and produces hollow metal-oxide nanospheres (Ni0.18 Mn0.45 Co0.37 Ox ) or core-shell metal hydroxide nanoflowers ([Ni0.15 Mn0.15 Co0.7 (OH)2 ](NO3 )0.2 ⋅H2 O), depending on the laser wavelengths. We propose two reaction pathways, either by photo-induced redox reaction or hydrolysis reaction, which are responsible for the formation of distinct nanostructures. The study of photon-induced materials growth shines light on the rational design of complex nanostructures with advanced functionalities. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Systematic Study of Technetium Production by Proton-Induced Reactions on Molybdenum

    NASA Astrophysics Data System (ADS)

    Lamere, Edward; Gilardy, Gwenaelle; Meisel, Zach; Moran, Michael; Skulski, Michael; Couder, Manoel

    2015-10-01

    Recent shortages in the world-wide supply of 99mTc have sparked interest in developing alternative production methods which do not rely on fission based 99Mo. The direct production of 99mTc from proton induced reactions on enriched 100Mo targets is one such approach. With this approach, 99mTc must be chemically extracted from the irradiated target and therefore radiopharmaceuticals will contain a mixture of all Tc-species produced from the proton bombardment. Commercial viability of cyclotron-produced 99mTc will depend on a number of factors including, production yield, radiochemical purity, and specific activity. Reactions on trace impurities in the targets has been shown to impact these factors dramatically. Precise cross-section measurements for not just the main reaction, 99mTc(p,2n), but for all Mo + p reactions that lead to Tc or Mo species are required for proper assessment of this 99mTc production technique. We will introduce a systematic study of proton-induced reactions on 92, 94-98, 100 Mo currently being performed at the University of Notre Dame. First results of 96Mo + p reactions will be presented. NRC-HQ-12-G-38-0073.

  19. Childhood Reactions to Terrorism-Induced Trauma: A Review of the Past 10 Years

    ERIC Educational Resources Information Center

    Fremont, Wanda P.

    2004-01-01

    Objective: To summarize the literature about the clinical presentation and treatment interventions of childhood reactions to terrorism-induced trauma. Method: The literature on children's responses to terrorist activities was reviewed. Results: Over the past 10 years, more research has emerged on the subject of terrorism in children. Many of the…

  20. Carbon nitride nanocrystals having cubic structure using pulsed laser induced liquid-solid interfacial reaction

    NASA Astrophysics Data System (ADS)

    Yang, G. W.; Wang, J. B.

    Carbon nitride nanocrystals were prepared using a pulsed laser induced liquid-solid interfacial reaction and transmission electron microscopy, while high resolution electron microscopy characterized their morphology and structure. It is important that the cubic-C3N4 phase was observed. The formation mechanism of the carbon nitride nanocrystals is also discussed.

  1. Oxidation induced ionization and reactions of metal carbide clusters (Nb, Zr, V, Ta)

    NASA Astrophysics Data System (ADS)

    Deng, H. T.; Kerns, K. P.; Bell, R. C.; Castleman, A. W.

    1997-11-01

    Following our recent report of the oxidation induced formation of Ti8C12+ (H.T. Deng, K.P. Kerns, and A.W. Castleman, Jr., J. Chem. Phys. 104 (1996) 4862), the oxidation induced ionization of niobium and zirconium carbide clusters are studied using a triple quadrupole mass spectrometer coupled with a laser induced plasma reaction source. It was found that reactions of both of these neutral carbide clusters with dioxygen leads to formation of carbide ions. The ion product distributions show that zirconium carbide clusters mainly take the form of Met--Car cations, but niobium carbide clusters favor a cubic-like crystalline pattern. Furthermore, reactions of mass-selected NbxCy+ with dioxygen result in a sequential loss of C2 units from NbxCy+, and leads to formation of Nbx+ and NbxC+ depending on y being an even or odd number. However, NbxCy+ shows comparably low reactivity towards nitrous oxide through a single oxygen abstraction mechanism. In comparison with the reaction products of VxCy+ with dioxygen, the complementary information obtained in the present study suggests that the C2 unit is a basic building block for formation of small early transition metal carbide clusters. The oxidation induced ionization mechanisms are also discussed in relation with the stability, ionization potentials, and structures of the clusters.

  2. The Temporal Stability of the Effects Induced by the Cued Reaction Time Task

    ERIC Educational Resources Information Center

    Versace, Francesco; Mazzetti, Michela; Codispoti, Maurizio

    2008-01-01

    The temporal stability of the effects induced by the Cued Reaction Time Task (CRTT) on the orienting of attention was assessed across four weekly sessions. Benefits, costs, and validity effects were computed for each session, and the correlation coefficients between each session were calculated (interindividual stability index). Intraindividual…

  3. New calculation method for initial exciton numbers on nucleon induced pre-equilibrium reactions

    SciTech Connect

    Tel, E.; Sarer, B.; Aydin, A.; Kaplan, A.

    2008-05-15

    In this study, we investigate the pre-equilibrium effect by using new evaluated geometry dependent hybrid model for the {sup 208}Pb (p,xn) reaction at 25.5 and 62.9 MeV incident proton energies. We also suggest that the initial neutron and proton exciton numbers for the nucleon induced precompound reactions be calculated from the neutron and proton density by using an effective nucleon-nucleon interaction with Skyrme force. We calculate the initial exciton numbers obtained from SKM* and SLy4 for a proton induced reaction on target nuclei {sup 208}Pb. The obtained results have been investigated and compared with the pre-equilibrium calculations and experimental results.

  4. Quantum Tunneling Contribution for the Activation Energy in Microwave-Induced Reactions.

    PubMed

    Kuhnen, Carlos A; Dall'Oglio, Evandro L; de Sousa, Paulo T

    2017-08-03

    In this study, a quantum approach is presented to explain microwave-enhanced reaction rates by considering the tunneling effects in chemical reactions. In the Arrhenius equation, the part of the Hamiltonian relative to the interaction energy during tunneling, between the particle that tunnels and the electrical field defined in the medium, whose spatial component is specified by its rms value, is taken into account. An approximate evaluation of the interaction energy leads to a linear dependence of the effective activation energy on the applied field. The evaluation of the rms value of the field for pure liquids and reaction mixtures, through their known dielectric properties, leads to an appreciable reduction in the activation energies for the proton transfer process in these liquids. The results indicate the need to move toward the use of more refined methods of modern quantum chemistry to calculate more accurately field-induced reaction rates and effective activation energies.

  5. 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.

  6. 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.

  7. Superoxide anion production by human spermatozoa as a part of the ionophore-induced acrosome reaction process.

    PubMed

    Griveau, J F; Renard, P; Le Lannou, D

    1995-04-01

    The involvement of superoxide anion (O2o-) in human sperm capacitation and/or acrosome reaction was investigated. Addition of superoxide dismutase (SOD) to the medium at the beginning of the capacitation process or 15 min before induction of the acrosome reaction, decreased the level of ionophore-induced acrosome reaction. Hyperactivation was unaffected by the presence of SOD during the capacitation process. Addition of calcium ionophore to the sperm suspension increased production of O2o- by the spermatozoa by four to five-fold and induced the acrosome reaction. In the presence of SOD, superoxide anion could not be detected in the medium and the rate of induced-acrosome reaction was decreased greatly. The presence of an inhibitor of protein kinase C inhibited the production of O2o- in the medium and reduced the induced-acrosome reaction. The production of O2o- and the acrosome reaction were also increased by exposure of spermatozoa to 12-myristate 13-acetate phorbol ester, a specific activator of protein kinase C. While the level of spontaneous acrosome reaction was not increased by the direct addition of O2o- to the medium, its presence induced the release of unesterified fatty acids from membrane phospholipids. These findings suggest that the production of O2o- by spermatozoa could be involved in the ionophore-induced acrosome reaction, possibly through the de-esterification of membrane phospholipids. However, this production of superoxide anion is not sufficient on its own to induce the acrosome reaction.

  8. Exhaled nitric oxide and breath condensate ph in asthmatic reactions induced by isocyanates.

    PubMed

    Ferrazzoni, Silvia; Scarpa, Maria Cristina; Guarnieri, Gabriella; Corradi, Massimo; Mutti, Antonio; Maestrelli, Piero

    2009-07-01

    We investigated the usefulness of measurements of fractional exhaled nitric oxide (FeNO) and pH of exhaled breath condensate (EBC) for monitoring airway response after specific inhalation challenges with isocyanates in sensitized subjects. Lung function (FEV(1)), FeNO, and pH in argon-deaerated EBC were measured before and at intervals up to 30 days after a specific inhalation challenge in 15 subjects with isocyanate asthma, in 24 not sensitized control subjects exposed to isocyanates, and in 3 nonasthmatic subjects with rhinitis induced by isocyanate. Induced sputum was collected before and 24 h after isocyanate exposure. Isocyanate-induced asthmatic reactions were associated with a rise in sputum eosinophil levels at 24 h (p < 0.01), and an increase in FeNO at 24 h (p < 0.05) and 48 h (p < 0.005), whereas FeNO level did not vary with isocyanate exposure in subjects with rhinitis and in control subjects. FeNO changes at 24 h positively correlated with corresponding sputum eosinophil changes (rho = 0.66, p < 0.001). A rise in pH was observed in the afternoon samples of EBC, irrespective of the occurrence of isocyanate-induced asthmatic reactions. We demonstrated that isocyanate-induced asthmatic reactions are associated with a consistent delayed increase in FeNO but not with the acidification of EBC.

  9. Effect of pre-equilibrium spin distribution on neutron-induced reaction cross sections

    SciTech Connect

    Dashdorj, D.; Mitchell, G. E.; Becker, J. A.; Wu, C. Y.; Chadwick, M. B.; Devlin, M.; Fotiades, N.; Kawano, T.; Nelson, R. O.; Garrett, P. E.; Kunieda, S.

    2008-04-17

    Cross section measurements were made of prompt gamma-ray production as a function of neutron energy using the germanium array for neutron induced excitations (GEANIE) at LANSCE. Measuring the prompt reaction gamma rays as a function of incident neutron energy provides more precise understanding of the spins populated by the pre-equilibrium reaction. The effect of the spin distribution in pre-equilibrium reactions has been investigated using the GNASH reaction code. Widely used classical theories such as the exciton model usually assume that the spin distribution of the pre-equilibrium reaction is the same as the spin distribution of the compound nucleus reaction mechanism. In the present approach, the pre-equilibrium reaction spin distribution was calculated using the quantum mechanical theory of Feshbach, Kerman, and Koonin (FKK). This pre-equilibrium spin distribution was incorporated into the GNASH code and the gamma-ray production cross sections were calculated and compared with experimental data. Spin distributions peak at lower spin when calculated with the FKK formulation than with the Compound Nuclear theory. The measured partial gamma-ray cross sections reflect this spin difference. Realistic treatment of the spin distribution improves the accuracy of calculations of gamma-ray production cross sections.

  10. 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.

  11. Effect of M-711 on experimental skin reactions induced by chemical mediators in rats.

    PubMed

    Shichinohe, K; Shimizu, M; Kurokawa, K

    1996-05-01

    We investigated the mechanism of anti-allergic action of Moku-boi-to (M-711) and effects on the skin reactions induced by chemical mediators as the model of allergic dermatitis. More than 20 mg/kg BW of M-711 significantly suppressed the enhancement of capillary permeability induced by histamine, LTC4, and anti-serum in the rat skin. Anti-histaminic effect of 40 mg/kg BW of M-711 was equipotent to same as the optimal doses of azelastine and diphenhydramine, respectively. As to anti-LTC4 action, 20 mg of M-711 was compared to the optimal dose of diphenhydramine. Those data showed that M-711 has the suppressive effects on the chemical mediators such as histamine and LTC4 and reduced the skin reaction induced by antigen-antibody response.

  12. 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

  13. 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.

  14. 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.

  15. Absolute Line Intensities in the 2nu3 Band of 16O12C32S

    PubMed

    Bermejo; Domenech; Santos; Bouanich; Blanquet

    1997-09-01

    The strengths of 100 lines in the 2nu3 band of 16O12C32S have been measured at high resolution in the spectral range 4069-4118 cm-1, using a tunable difference-frequency laser spectrometer. These intensities were obtained by fitting Voigt profiles to the measured shapes of the lines. The vibrational transition moment [(2.141 ± 0.020) x 10(-2) D] and the absolute intensity (16.19 ± 0.24 cm-2 atm-1 at 296 K) of the 2nu3 band of 16O12C32S are determined from these linestrength measurements. Copyright 1997 Academic Press. Copyright 1997Academic Press

  16. 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

  17. Search for fusion oscillations in the /sup 16/O+/sup 28/Si system

    SciTech Connect

    Betts, R.R.; Hindi, M.M.; DiCenzo, S.B.; Parker, P.D.

    1980-01-01

    The yields of gamma rays from evaporation residues following the fusion of /sup 16/O+/sup 28/Si have been measured over the energy range 50 --65 MeV in a search for structure similar to that found in the backward angle elastic scattering of this system. No such structure is seen at a level of about 4% of the total fusion cross section.

  18. 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.

  19. [Study on the toxic reaction induced by single dose of qingkailing injection].

    PubMed

    Chen, Li-jing; Wang, Yan; He, Shuai; Liao, Guo-ping; Zhang, Zhong-yi

    2011-02-01

    To study the toxic reaction induced by Qingkailing Injection. Kunming mice were injected single dose of Qingkailing Injection via tail vein and observed for 14 days to test the toxic reaction of the drug. According to Chinese Pharmacopoeia, hemolysis tests were conducted on the injections of different lots and each ingredient of the injection. Toxic reaction induced by single dose of injection--with dose increasing,mice quickly showed different responses such as hypodynamia, convulsion, syncope and even death after injection. In the high dose group, blood routine detection showed that mice have lower counts of RBC, WBC and lower content of hemoglobin; The pulmonary pathological sections of dead mice showed significant hyperemia. And there were no significant difference in the contents of serum electrolyte (K+, Na+, Ca2+) between normal saline control group and Qingkailing injection group. Hemolysis test in vitro--Honeysuckle extraction (significantly) and gardenia extraction which were components of Qing-kailing injection caused hemolysis in certain dose; While gardenia, pearl shell and isatis root extraction caused RBC agglutination. With higher concentration, the Qingkailing injections of different lot caused different degree of hemolysis. There was no significant difference in the hemolysis test in vitro between the group of Balb/C mice which were sensitized by Qingkailing injection or not. In clinical practice some adverse reactions induced by Qingkailing injection occurred concomitantly with acute hemolysis within vessels, which might be caused by honeysuckle and gardenia. And the hemolysis was independent of allergy.

  20. Effect of magnetic field on the zero valent iron induced oxidation reaction.

    PubMed

    Kim, Dong-hyo; Kim, Jungwon; Choi, Wonyong

    2011-08-30

    The magnetic field (MF) effect on the zero valent iron (ZVI) induced oxidative reaction was investigated for the first time. The degradation of 4-chlorophenol (4-CP) in the ZVI system was employed as the test oxidative reaction. MF markedly enhanced the degradation of 4-CP with the concurrent production of chlorides. The consumption of dissolved O(2) by ZVI reaction was also enhanced in the presence of MF whereas the competing reaction of H(2) production from proton reduction was retarded. Since the ZVI-induced oxidation is mainly driven by the in situ generated hydroxyl radicals, the production of OH radicals was monitored by the spin trap method using electron spin resonance (ESR) spectroscopy. It was confirmed that the concentration of trapped OH radicals was enhanced in the presence of MF. Since both O(2) and Fe(0) are paramagnetic, the diffusion of O(2) onto the iron surface might be accelerated under MF. The magnetized iron can attract oxygen on itself, which makes the mass transfer process faster. As a result, the surface electrochemical reaction between Fe(0) and O(2) can be accelerated with the enhanced production of OH radicals. MF might retard the recombination of OH radicals as well. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. 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.

  2. Existence of inelastic supernumerary nuclear rainbow in 16O+12C scattering

    NASA Astrophysics Data System (ADS)

    Ohkubo, S.; Hirabayashi, Y.; Ogloblin, A. A.

    2017-08-01

    The existence of a supernumerary nuclear rainbow in inelastic scattering is reported. This is done by studying inelastic 16O scattering from 12C, exciting the 2+ (4.44 MeV) state of 12C and elastic scattering at the incident energies in the range 124-200 MeV, using the coupled channels method. An extended double folding potential is used. This is derived from realistic wave functions for 12C and 16O calculated with a microscopic α cluster model and a finite-range density-dependent nucleon-nucleon force. Excitations to the 2+ (4.44 MeV), 3- (9.64 MeV), and 4+ (14.08 MeV) states of 12C, and the 3- (6.13 MeV) and 2+ (6.92 MeV) states of 16O are included in the coupled channels calculations. The emergence of the supernumerary bow is understood by the properties of both the Luneburg-lens-like potential in the internal region and diffuse attraction in the outer region. The existence of a supernumerary rainbow for inelastic scattering in addition to the existence of a dynamically created secondary rainbow and a dynamically refracted primary rainbow for elastic scattering, which are not observed in meteorological rainbows, further deepens the understanding of nuclear rainbows.

  3. Measurement of γ-rays from giant resonances of 12 C and 16 O

    NASA Astrophysics Data System (ADS)

    Ou, Iwa; RCNP E398 Collaboration

    2014-09-01

    Oxygen and carbon are the most common targets in neutrino experiments such as Super Kamiokande (H2O) and Daya-Bay (liquid scintillator). The γ-ray production from neutral current (NC) ν-16 O and ν-12 C (inelastic scattering) is applicable to the measurement of core-collapse supernova neutrinos. A core-collapse supernova emits all type of neutrino with mean energy of 10--20 MeV. In most neutrino detectors, the main signal is charged current event which can detect electron type neutrino only. While in NC event, mu and tau type neutrino can be detected. Therefore NC event is very important for the understanding of supernova mechanism. NC events will be identified by detecting the γ-rays emitted from giant resonances of 16O and 12C. But there is no experimental data for γ-ray production from these resonances. Our goal is to measure the γ-ray emission probability and energy spectrum from these resonances. We carried out an experiment to measure γ-rays from giant resonance of 16O and 12C using 400 MeV proton beam, magnetic spectrometer ``Grand Raiden'' and NaI(Tl) γ-detecter at Research Center for Nuclear Physics in Osaka University. In this talk, experimental setup and current analysis status will be presented.

  4. 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

  5. Recovery studies of impact-induced metal/polymer reactions in titianium based composites

    SciTech Connect

    Woody, Diana L.; Davis, Jeffrey J.; Scott Deiter, J.

    1998-07-10

    This paper will discuss the effect of rapid plastic flow upon a porous mixture containing titanium and Teflon. The unconfined samples were impacted at 13 m/s to induce a plastic flow. With the addition of Teflon, reactions have been observed. A two color infrared detector was used for real time emission measurements of the reacting materials. Micrographs show a region of decomposition surrounded by an unaltered area. X-ray diffraction results showed that the area of reaction had TiC whereas the surrounding area contained titanium. There was no solid Teflon recovered. The effect of the addition of aluminum and silicon to the mixture was also observed.

  6. Vibrational analysis of carbonyl modes in different stages of light-induced cyclopyrimidine dimer repair reactions

    NASA Astrophysics Data System (ADS)

    Schmitz, Matthias; Tavan, Paul; Nonella, Marco

    2001-11-01

    The formation of cyclopyrimidine dimers is a DNA defect, which is repaired by the enzyme DNA photolyase in a light-induced reaction. Radical anions of the dimers have been suggested to occur as short-lived intermediates during repair. For their identification time-resolved Fourier-transform infrared (FTIR) spectroscopy will be a method of choice. To support and guide such spectroscopic studies we have calculated the vibrational spectra of various pyrimidine compounds using density functional methods. Our results suggest that the carbonyl vibrations of these molecules can serve as marker modes to identify and distinguish intermediates of the repair reaction.

  7. 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.

  8. 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.

  9. 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.

  10. Effects of midazolam and phenobarbital on brain oxidative reactions induced by pentylenetetrazole in a convulsion model.

    PubMed

    Arai, Yukiko; Maeda, Shigeru; Higuchi, Hitoshi; Tomoyasu, Yumiko; Shimada, Masahiko; Miyawaki, Takuya

    2012-04-01

    Brain oxidative reactions are involved in epilepsy as well as neurodegenerative diseases. In animal convulsion models, some anticonvulsants have been found to suppress oxidative reactions associated with convulsions. However, the effect of anticonvulsants on brain oxidative reactions has not fully been clarified. Midazolam and phenobarbital are often used as an intravenous anesthetic, and are known to have anticonvulsive effect, but antioxidative effect of these drugs has rarely been studied. Thus, the purpose of this study was to evaluate the effects of these drugs on the degree of convulsions and brain oxidative reactions in an animal convulsion model. In order to evaluate brain oxidative reactions, we measured malondialdehyde (MDA) level and heme oxygenase (HO)-1 mRNA expression level in the brain of mice in a convulsion model generated by a single injection of pentylenetetrazole (PTZ). We evaluated the effects of midazolam and phenobarbital on the degree of PTZ-induced convulsions and on the changes in brain MDA level and HO-1 mRNA expression level. After PTZ injection, severe convulsions were observed in all mice. MDA level was increased in the whole brain, while HO-1 mRNA expression level was increased only in the hippocampus. Both midazolam and phenobarbital prevented the convulsions and suppressed the increase in both MDA level and HO-1 mRNA expression level in the brain. In this study, both midazolam and phenobarbital suppressed PTZ-induced MDA and HO-1 reactions in the brain, suggesting that these drugs inhibit brain oxidative reactions in a convulsion model.

  11. CO-laser-induced photochemical reaction of UF6 with HCl for the isotope separation of uranium hexafluoride

    NASA Astrophysics Data System (ADS)

    Ding, Hong-Bin; Shen, Z. Y.; Zhang, Cun H.

    1993-05-01

    In this paper, we report the results of CO-laser induced photochemical reaction of UF6 with HCl for the isotope separation of uranium hexafluoride, we also discussed that the molecular collision inducing V-T, V-V relaxation process affects on the selectivity of the isotope separation. The obtained quantum coefficiency of the reaction is about 0.34.

  12. 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

  13. Pre-hospital treatment of bee and wasp induced anaphylactic reactions: a retrospective study.

    PubMed

    Ruiz Oropeza, Athamaica; Mikkelsen, Søren; Bindslev-Jensen, Carsten; Mortz, Charlotte G

    2017-01-14

    Bee and wasp stings are among the most common triggers of anaphylaxis in adults representing around 20% of fatal anaphylaxis from any cause. Data of pre-hospital treatment of bee and wasp induced anaphylactic reactions are sparse. This study aimed to estimate the incidence of bee and wasp induced anaphylactic reactions, the severity of the reactions and to correlate the pre-hospital treatment with the severity of the anaphylactic reaction. Retrospective and descriptive study based on data from the Mobile Emergency Care Units (MECUs) in the Region of Southern Denmark (2008 only for Odense and 2009-2014 for the whole region). Discharge summaries with diagnosis related to anaphylaxis according to the International Classification of Diseases 10 (ICD-10) were reviewed to identify bee and wasp induced anaphylactic reactions. The severity of the anaphylactic reaction was assessed according to Sampson's severity score and Mueller's severity score. Treatment was evaluated in relation to administration of adrenaline, glucocorticoids and antihistamine. We identified 273 cases (Odense 2008 n = 14 and Region of Southern Denmark 2009-2014 n = 259) of bee and wasp induced anaphylaxis. The Incidence Rate was estimated to 35.8 cases per 1,000,000 person year (95% CI 25.9-48.2) in the Region of Southern Denmark during 2009-2014. According to Sampson's severity score, 65% (n = 177) of the cases were graded as moderate to severe anaphylaxis (grade 3-5). Almost one third of cases could not be graded according to Mueller's severity score. Adrenaline was administrated in 54% (96/177) of cases with moderate to severe anaphylaxis according to Sampson's severity score, compared to 88% receiving intravenous glucocorticoids (p < 0.001) and 91% receiving intravenous antihistamines (p < 0.001). Even in severe anaphylaxis (grade 5) adrenaline was administered in only 80% of the cases. Treatment with adrenaline is not administered in accordance with international guidelines

  14. 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.

  15. Light-induced structural changes in a photosynthetic reaction center caught by Laue diffraction.

    PubMed

    Wöhri, Annemarie B; Katona, Gergely; Johansson, Linda C; Fritz, Emelie; Malmerberg, Erik; Andersson, Magnus; Vincent, Jonathan; Eklund, Mattias; Cammarata, Marco; Wulff, Michael; Davidsson, Jan; Groenhof, Gerrit; Neutze, Richard

    2010-04-30

    Photosynthetic reaction centers convert the energy content of light into a transmembrane potential difference and so provide the major pathway for energy input into the biosphere. We applied time-resolved Laue diffraction to study light-induced conformational changes in the photosynthetic reaction center complex of Blastochloris viridis. The side chain of TyrL162, which lies adjacent to the special pair of bacteriochlorophyll molecules that are photooxidized in the primary light conversion event of photosynthesis, was observed to move 1.3 angstroms closer to the special pair after photoactivation. Free energy calculations suggest that this movement results from the deprotonation of this conserved tyrosine residue and provides a mechanism for stabilizing the primary charge separation reactions of photosynthesis.

  16. 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

  17. Risk factors of allopurinol-induced severe cutaneous adverse reactions in a Thai population.

    PubMed

    Saksit, Niwat; Tassaneeyakul, Wichittra; Nakkam, Nontaya; Konyoung, Parinya; Khunarkornsiri, Usanee; Chumworathayi, Pansu; Sukasem, Chonlaphat; Suttisai, Sumitra; Piriyachananusorn, Napacha; Tiwong, Pawinee; Chaiyakunapruk, Nathorn; Sawanyawisuth, Kittisak; Rerkpattanapipat, Ticha; Tassaneeyakul, Wongwiwat

    2017-07-01

    Allopurinol is one of the most common causes of severe cutaneous adverse drug reactions (SCARs) including drug reactions with eosinophilia and systemic symptoms (DRESS), Stevens-Johnson syndrome (SJS), and toxic epidermal necrolysis (TEN). This study identified the risk factors associated with the development of allopurinol-induced SCARs in a Thai population. Eighty-six allopurinol-induced SCARs (i.e. 19 DRESS and 67 SJS/TEN) and 182 allopurinol-tolerant patients were enrolled in the study. The HLA-B*58:01 allele was determined. Clinical and medicinal data were collected. Results from multivariate analysis showed that only the HLA-B*58:01 and female sex were identified as risk factors of allopurinol-induced SCARs in this Thai population. Patients who carried the HLA-B*58:01 allele were at a higher risk of allopurinol-induced DRESS [odds ratio (OR)=149.2, 95% confidence interval (CI)=24.0-∞, P<1.00×10]. Similar results were observed in allopurinol-induced SJS/TEN (OR=175.0, 95% CI=44.3-690.9, P=1.69×10). The risk of allopurinol-induced SCARs in women was higher than that in men (OR=4.6, 95% CI=1.4-15.6, P=1.44×10). The overall mortality rate of allopurinol-induced SCARs was 11.39% and a higher mortality rate was observed in elderly women. Among the risk factors identified, the HLA-B*58:01 allele had the greatest impact on the development of both phenotypes of allopurinol-induced SCARs in this studied Thai population. In case HLA-B*58:01 genotyping cannot be accessed, close monitoring of allopurinol usage, especially in elderly women with impaired renal function, is necessary to reduce the mortality rate of these life-threatening SCARs.

  18. 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.

  19. Surface-induced dissociations and reactions of acetonitrile monomer, dimer and trimer ions

    NASA Astrophysics Data System (ADS)

    Mair, C.; Herman, Z.; Fedor, J.; Lezius, M.; Märk, T. D.

    2003-01-01

    Dissociations and reactions induced by impact of acetonitrile monomer ions (CH3CN+,CD3CN+), dimer ions [(CH3CN)2+, (CD3CN)2+] and trimer ions [(CD3CN)3+] on a hydrocarbon-covered stainless-steel surface were investigated over the projectile energy range of 3-70 eV. Both simple dissociations of the projectile ion and chemical reactions of H-atom transfer from the surface material (followed by dissociations of the protonated projectile ion formed) were observed for the monomer ions. Results obtained for the dimer ions (CD3CN)2+ indicate the formation of the protonated acetonitrile ions via surface-induced reactions in two ways: (i) an intracluster ion-molecule reaction followed by dissociation to form CD3CND+, and (b) a hydrogen pick-up reaction from the surface material during the interaction of the dimer ion with the surface leading to CD3CNH+. A simple model based on the Brauman double-well potential—suggested earlier to explain the occurrence of analogous reactions in acetone cluster ion/surface interactions—accounts well for the formation of both product ions. Moreover, in adition to these protonated species, considerable amounts of nondissociated dimer ions were observed after acetonitrile dimer cation/surface collisions with energies up to 25 eV. Similarly, both trimer ions (up to 20 eV) and dimer ions (up to 30 eV) were observed in acetonitrile trimer cation/surface interactions. This indicates that unimolecular dissociation kinetics governs the product formation for these cluster ion/surface interactions.

  20. Neutral Current {nu} Induced Reactions in Nuclei at Supernova Neutrino Energies

    SciTech Connect

    Chauhan, S.; Athar, M. Sajjad; Singh, S. K.

    2011-11-23

    We calculate cross sections for the neutral current induced neutrino/antineutrino reaction from {sup 208}Pb target and applied it to study Supernova neutrino event rates. The calculations are done in local density approximation taking into account Pauli blocking, Fermi motion effects and renormalization of weak transition strengths in the nuclear medium. The numerical results for the neutrino nucleus total cross sections have been averaged over the various Supernova neutrino/antineutrino fluxes available in literature.

  1. Spatial Symmetry Breaking in the Belousov-Zhabotinsky Reaction with Light-Induced Remote Communication

    SciTech Connect

    Hildebrand, M.; Skodt, H.; Showalter, K.

    2001-08-20

    Domains containing spiral waves form on a stationary background in a photosensitive Belousov-Zhabotinsky reaction with light-induced alternating nonlocal feedback. Complex behavior of colliding and splitting wave fragments is found with feedback radii comparable to the spiral wavelength. A linear stability analysis of the uniform stationary states in an Oregonator model reveals a spatial symmetry breaking instability. Numerical simulations show behavior in agreement with that found experimentally and also predict a variety of other new patterns.

  2. 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.

  3. 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.

  4. Infrared laser induced organic reactions. Technical progress report, October 15, 1980

    SciTech Connect

    Farneth, W E

    1980-03-01

    As outlined in the original proposal, experiments of two types have been pursued. In the first, the competition among activation, deactivation, and chemical reaction rates in laser-activated organic vapors were investigated. In the second, potential applications of infrared multiphoton activation to studies of organic reaction dynamics were explored. For the first phase, infrared laser induced chemistry of vinylcyclopropane irradiated with a CO/sub 2/ TEA laser at relatively low pressures has been thoroughly investigated. Changes in yield and product distribution as a function of bath gas pressure, laser fluence, laser frequency, number of pulses, and laser intensity have been systematically studied. Concurrently, model calculations employing RRKM theory have been undertaken. From this combination, conclusions have been drawn about various aspects of the energy distribution among reacting molecules. Also, to test the assumption that the internal energy of the activated reactant is randomly distributed, tracer-induced reactions of bicyclopropyl-d/sub 4/ and diethylcarbonate have been investigated. The second phase, application of multiphoton activation to problems in organic reactivity, is less advanced. A substituted oxetane was prepared and irradiated with CO/sub 2/ laser and its decomposition studied. Infrared laser activation of heterogeneous reactions are also being investigated by examining the reactivity of carbon surfaces during laser irradiation.

  5. 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.

  6. 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

  7. 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.

  8. Investigation of the shock-induced chemical reaction (SICR) in Ni + Al nanoparticle mixtures.

    PubMed

    Xiong, Yongnan; Xiao, Shifang; Deng, Huiqiu; Zhu, Wenjun; Hu, Wangyu

    2017-07-21

    Molecular dynamics (MD) simulations are used to investigate the shock-compression response of Ni + Al spherical nanoparticles arranged in a NaCl-like structure. The deformation and reaction characteristics are studied from the particle level to the atomic scale at various piston velocities. Shock-induced chemical reactions (SICRs) occur during non-equilibrium processes, accompanied by a sharp rise in temperature and rapid mixing of atoms. The preferentially deformed Al particles form a high-speed mass flow relative to the Ni at the shock front, which impinges on the Ni particles, and mixing of Ni and Al atoms occurs immediately at the interface. The particle velocity dispersion (PVD) that appears at the shock front has important implications for the initiation of shock-induced chemical reactions. We show that dislocations are mainly generated at the beginning of particle deformation or at the shock front, and do not directly affect the occurrence of SICRs. The intimate contact of the molten Al and the amorphous Ni is found to be critical to the subsequent reactions for the extensive mixing of Ni and Al. We conclude that the mechanisms of SICRs involve mechanochemical processes near the shock front and subsequent interdiffusion processes.

  9. 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

  10. Projectile-breakup-induced fission-fragment angular distributions in the 6Li+232Th reaction

    NASA Astrophysics Data System (ADS)

    Pal, A.; Santra, S.; Chattopadhyay, D.; Kundu, A.; Ramachandran, K.; Tripathi, R.; Roy, B. J.; Nag, T. N.; Sawant, Y.; Sarkar, D.; Nayak, B. K.; Saxena, A.; Kailas, S.

    2017-08-01

    Background: Experimental anisotropy in fission-fragment (FF) angular distribution in reactions involving weakly bound stable projectiles with actinide targets are enhanced compared to statistical saddle-point model (SSPM) predictions. Contributions from breakup- or transfer-induced fission to total fission are cited as possible reasons for such enhancement. Purpose: To identify the breakup- or transfer-induced fission channels in 6Li+232Th reaction and to investigate their effects on FF angular anisotropy. Methods: The FF angular distributions have been measured exclusively at three beam energies (28, 32, and 36 MeV) around the Coulomb barrier in coincidence with projectile breakup fragments like α , d , and p using Si strip detectors. The angular anisotropy obtained for different exclusive breakup- or transfer-induced fission channels are compared with that for total fission. SSPM and pre-equilibrium fission models have been employed to obtain theoretical FF angular anisotropy. Results: Angular anisotropy of the fission fragments produced by different transfer- or breakup-induced fission reactions have been obtained separately in the rest frame of respective recoiling nuclei. Some of these anisotropies were found to be stronger than those of the inclusive fission. Overall angular distributions of transfer or breakup fission, integrated over all possible recoil angles with weight factor proportional to differential cross section of the complementary breakup fragment emitted in coincidence in all possible directions, were obtained. It was observed that the overall FF angular anisotropy for each of these fission channels is less than or equal to the anisotropy of total fission at all the measured energies. Assuming isotropic out-of-plane correlations between the fission fragments and light-charged particles, the overall breakup- or transfer-induced fission fragment angular distributions do not explain the observed enhancement in FF anisotropy of total fission. Pre

  11. Childhood reactions to terrorism-induced trauma: a review of the past 10 years.

    PubMed

    Fremont, Wanda P

    2004-04-01

    To summarize the literature about the clinical presentation and treatment interventions of childhood reactions to terrorism-induced trauma. The literature on children's responses to terrorist activities was reviewed. Over the past 10 years, more research has emerged on the subject of terrorism in children. Many of the effects of terrorism-induced trauma are similar to the effects of natural and man-made trauma. Children's responses include acute stress disorder, posttraumatic stress disorder, anxiety, depression, regressive behaviors, separation problems, sleep difficulties, and behavioral problems. However, several aspects of terrorist attacks result in unique stressors and reactions and pose specific challenges for treatment. The unpredictable, indefinite threat of terrorist events, the profound effect on adults and communities, and the effect of extensive terrorist-related media coverage exacerbates underlying anxieties and contributes to a continuous state of stress and anxiety. Intervention strategies include early community-based interventions, screening of children at risk, triage and referral, and trauma-loss-focused treatment programs. Advances have been made in the research of childhood reactions to terrorism-induced trauma. Further research is needed to identify children at risk and to determine the long-term impact on children's development. Although the preliminary results of interventions developed to help children are promising, outcome data have not been examined, and further research is needed to evaluate their effectiveness.

  12. 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.

  13. 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.

  14. Grain boundary diffusion induced reaction layer formation in Fe/Pt thin films

    NASA Astrophysics Data System (ADS)

    Katona, G. L.; Vladymyrskyi, I. A.; Makogon, I. M.; Sidorenko, S. I.; Kristály, F.; Daróczi, L.; Csik, A.; Liebig, A.; Beddies, G.; Albrecht, M.; Beke, D. L.

    2014-04-01

    The solid-state reaction in Pt(15 nm)/Fe(15 nm) and Pt(15 nm)/Ag(10 nm)/Fe(15 nm) thin films after post-annealing at 593 K and 613 K for different annealing times has been studied. The structural properties of these samples were investigated by various methods including depth profiling with secondary neutral mass spectrometry, transmission electron microscopy, and X-ray diffraction. It is shown that after annealing at the above temperatures where the bulk diffusion processes are still frozen, homogeneous reaction layers of FePt and FePt with about 10 at.% Ag, respectively, have been formed. Corresponding depth profiles of the element concentrations revealed strong evidence that the formation mechanism is based on a grain boundary diffusion induced solid-state reaction in which the reaction interfaces sweep perpendicularly to the original grain boundary. Interestingly, X-ray diffraction indicated that in both thin-film systems after the solid-state reaction the ordered L10 FePt phase, which is the requested phase for future magnetic data storage applications, is also present.

  15. 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.

  16. Laser Shock Compression Induced Reaction and Spalling of Reactive Ni-Al Laminate Composites

    NASA Astrophysics Data System (ADS)

    Wei, Chung-Ting; Maddox, Brian; Weihs, Timothy; Nesterenko, Vitali; Meyers, Marc

    2009-06-01

    Reactive laminates produced by rolling layers of Ni and Al (bilayer thicknesses of 8.3 and 48μm) were subjected to extreme laser loading. Laser energy was varied between ˜8.3 x 103J/cm2 (estimated initial pressure 140GPa) and ˜3.33 x 104J/cm2 (˜350GPa) with two initial durations: 3 and 8ns. Hydrodynamic calculations (HYADES) were used to predict propagation of shockwave in laminates. SEM and EDS were carried out to study the damage, failure modes, reaction propagation and spall. The 8.3μm bilayer thickness laminate exhibited localized interfacial reaction at 3.33 x 104J/cm2 laser energy; the reaction products were identified as NiAl and Al rich intermetallic compounds. The reactionfront forming intermetallic compounds propagated about 50μm into the sample with thinner bi-layer thickness (8.3μm). Estimated cooling rate was 5.7 x 105 K/s. The estimated highest temperature was about 1470K. Increase in the duration of laser shock wave induces increased reaction, which occurs also in the thicker bilayer laminate samples (48μm bi-layer thickness). The laser shock methodology is well suited to investigate the threshold conditions for dynamic mechanical reaction initiation.

  17. 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.

  18. 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

  19. Polarization transfer in inelastic proton scattering from 4{sup {minus}} states in {sup 16}O at 350 MeV

    SciTech Connect

    Larson, B.; Hicks, K.; Haeusser, O.; Abegg, R.; Alford, W.; Celler, A.; Frekers, D.; Helmer, R.; Henderson, R.; Jackson, K.P.; Jeppesen, R.; Mildenberger, J.; Miller, C.A.; Pointon, B.; Schubank, R.; Vetterli, M.; Yen, S. |||

    1996-04-01

    This experiment has measured cross sections, analyzing powers, and the spin observables {ital P}, {ital D}{sub {ital ss}}{sup {prime}}, {ital D}{sub {ital sl}}{sup {prime}}, {ital D}{sub {ital nn}}{sup {prime}}, {ital D}{sub {ital ll}}{sup {prime}}, {ital D}{sub {ital ls}}{sup {prime}} for the reaction {sup 16}O({ital p},{ital p}{sup {prime}}) at 350 MeV populating three 4{sup {minus}} states. These {open_quote}{open_quote}stretched{close_quote}{close_quote} states, at excitation energies of 17.79 MeV, 19.80 MeV (both mainly {ital T}=0), and 18.98 MeV (mainly {ital T}=1), have well known nuclear structure and are used as a nuclear filter to examine the tensor and spin-orbit components of the effective nucleon-nucleus interaction at 350 MeV. A complete set of spin observables was obtained at an angle of 22{degree} in the laboratory frame, whereas the {ital D}{sub {ital ss}}{sup {prime}} and {ital D}{sub {ital sl}}{sup {prime}} observables were measured at laboratory angles of 17, 22, 27, and 32 degrees. The data are compared with distorted-wave impulse approximation calculations from several theoretical models. {copyright} {ital 1996 The American Physical Society.}

  20. 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.

  1. Enantiomer-Selective Photo-Induced Reaction of Protonated Tryptophan with Disaccharides in the Gas Phase.

    PubMed

    Doan, Thuc N; Fujihara, Akimasa

    2017-07-08

    In order to investigate chemical evolution in interstellar molecular clouds, enantiomer-selective photo-induced chemical reactions between an amino acid and disaccharides in the gas phase were examined using a tandem mass spectrometer containing an electrospray ionization source and a cold ion trap. Ultraviolet photodissociation mass spectra of cold gas-phase noncovalent complexes of protonated tryptophan (Trp) enantiomers with disaccharides consisting of two D-glucose units, such as D-maltose or D-cellobiose, were obtained by photoexcitation of the indole ring of Trp. NH2CHCOOH loss via cleavage of the Cα-Cβ bond in Trp induced by hydrogen atom transfer from the NH3(+) group of a protonated Trp was observed in a noncovalent heterochiral H(+)(L-Trp)(D-maltose) complex. In contrast, a photo-induced chemical reaction forming the product ion with m/z 282 occurs in homochiral H(+)(D-Trp)(D-maltose). For D-cellobiose, both NH2CHCOOH elimination and the m/z 282 product ion were observed, and no enantiomer-selective phenomena occurred. The m/z 282 product ion indicates that the photo-induced C-glycosylation, which links D-glucose residues to the indole moiety of Trp via a C-C bond, can occur in cold gas-phase noncovalent complexes, and its enantiomer-selectivity depends on the structure of the disaccharide.

  2. Enantiomer-Selective Photo-Induced Reaction of Protonated Tryptophan with Disaccharides in the Gas Phase

    NASA Astrophysics Data System (ADS)

    Doan, Thuc N.; Fujihara, Akimasa

    2017-07-01

    In order to investigate chemical evolution in interstellar molecular clouds, enantiomer-selective photo-induced chemical reactions between an amino acid and disaccharides in the gas phase were examined using a tandem mass spectrometer containing an electrospray ionization source and a cold ion trap. Ultraviolet photodissociation mass spectra of cold gas-phase noncovalent complexes of protonated tryptophan (Trp) enantiomers with disaccharides consisting of two uc(d)-glucose units, such as uc(d)-maltose or uc(d)-cellobiose, were obtained by photoexcitation of the indole ring of Trp. NH2CHCOOH loss via cleavage of the Cα-Cβ bond in Trp induced by hydrogen atom transfer from the NH3 + group of a protonated Trp was observed in a noncovalent heterochiral H+(uc(l)-Trp)(uc(d)-maltose) complex. In contrast, a photo-induced chemical reaction forming the product ion with m/z 282 occurs in homochiral H+(uc(d)-Trp)(uc(d)-maltose). For uc(d)-cellobiose, both NH2CHCOOH elimination and the m/z 282 product ion were observed, and no enantiomer-selective phenomena occurred. The m/z 282 product ion indicates that the photo-induced C-glycosylation, which links uc(d)-glucose residues to the indole moiety of Trp via a C-C bond, can occur in cold gas-phase noncovalent complexes, and its enantiomer-selectivity depends on the structure of the disaccharide.

  3. Proton rapidity distributions from 60 GeV/n sup 16 O+Au collisions

    SciTech Connect

    Baechler, J.; Hoffman, M.; Runge, K.; Schmoetten, E. . Fakultaet fuer Physik); Bartke, J.; Gladysz, E. ); Bialkowska, H. ); Bock, R.; Brockmann, R.; Guerra, C.; Humanic, T.; Sandoval, A. ); Buncic, P.; Ljubicic, A.

    1990-05-01

    An analysis of the proton rapidity distribution in central {sup 16}O+Au collisions at 60 GeV/n measured in the NA35 streamer chamber detector at the CERN SPS is presented. The charge excess of positive particles over negative particles was measured. The rapidity distribution of the charge excess which can be associated with the primordial protons in the collision is studied in terms of the nuclear stopping power and is compared to the predictions of various models. 7 refs., 2 figs.

  4. 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.

  5. Microscopic Calculation of the Inclusive Electron Scattering Structure Function in 16O

    NASA Astrophysics Data System (ADS)

    Mihaila, Bogdan; Heisenberg, Jochen H.

    2000-02-01

    We calculate the charge form factor and the longitudinal structure function for 16O and compare with the available experimental data, up to a momentum transfer of 4 fm-1. The ground-state correlations are generated using the coupled-cluster [ exp\\(S\\)] method, together with the realistic v18 NN interaction and the Urbana IX three-nucleon interaction. Center-of-mass corrections are dealt with by adding a center-of-mass Hamiltonian to the usual internal Hamiltonian, and by means of a many-body expansion for the computation of the observables measured in the center-of-mass system.

  6. 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.

  7. 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

  8. 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.

  9. Sulthiame-induced drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome.

    PubMed

    Fong, Choong Yi; Hashim, Nurmaira; Gan, Chin Seng; Chow, Tak Kuan; Tay, Chee Geap

    2016-11-01

    Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a rare and potentially life-threatening acute drug-induced hypersensitivity reaction. Antiepileptic drugs (AEDs) predominantly aromatic AEDs are commonly reported in DRESS. To date there are no reports of sulthiame AED causing DRESS syndrome. We report a 10-year-old girl of Indian descent with AED resistant epilepsy on maintenance sodium valproate and clonazepam. Sulthiame AED was initiated to try to improve her seizure control. Five weeks after commencing sulthiame, she developed fever with a diffuse erythematous morbilliform maculopapular rash, elevated transaminases and atypical lymphocytes. At day 3 of illness, she deteriorated with worsening elevation of liver transaminases, thrombocytopenia, progression of rash, hepatosplenomegaly, pneumonitis and markedly elevated inflammatory markers. Immunomodulatory treatment of pulse methylprednisolone was given from day 7 which was associated with improvement inflammatory markers and complete resolution of rash from day 30 of illness. The diagnosis of sulthiame-induced DRESS syndrome was made based on clinical, laboratory and skin histology findings. She was HLA-B heterozygous for HLA-B(∗)15:123 and 15:240 and HLA-A homozygous for HLA-A(∗)11:01:09. Both these HLA-A and HLA-B typing has not been reported before in cutaneous drug reactions. This is the first reported case of sulthiame-induced DRESS syndrome. Our case expands the list of possible susceptible HLA alleles associated with cutaneous drug reactions. It also raises the awareness of possible DRESS syndrome among patients commenced on sulthiame who will require immediate discontinuation of sulthiame and consideration of prompt treatment of corticosteroids. Copyright © 2016 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

  10. Noise-induced order in the chaos of the Belousov-Zhabotinsky reaction.

    PubMed

    Yoshimoto, Minoru; Shirahama, Hiroyuki; Kurosawa, Shigeru

    2008-07-07

    Noise can stabilize a metastable state in such a way that the system remains in this state for a longer time than in the absence of noise. When this phenomenon is observed in chaos, it is called "noise-induced order." We have experimentally detected noise-induced order in the Belousov-Zhabotinsky reaction. That is, when noise is added to the chaos with the flow rate near the period-three oscillation, a decrease of the maximum Lyapunov exponent and a convergence of the Fourier spectrum are observed. Moreover, the analysis on the one-dimensional return map reveals that noise-induced order is caused by the convergence of the chaotic trajectory into the laminar region.

  11. 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.

  12. 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

  13. 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.

  14. 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

  15. 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.

  16. Patient-Induced Reaction Forces and Moments Are Influenced by Variations in Spinal Manipulative Technique.

    PubMed

    D'Angelo, Kevin; Triano, John J; Kawchuk, Gregory N; Howarth, Samuel J

    2017-01-15

    An in vivo biomechanical study. The aim of the present study was to quantify and compare the reaction loads for two spinal manipulation therapy (SMT) procedures commonly used for low back pain using a biomechanical computer model. Contemporary computer-driven rigid linked-segment models (LSMs) have made it feasible to analyze low back kinetics and kinematics during various activities including SMT procedures. Currently, a comprehensive biomechanical model analyzing actual differences in loading effects between different SMT procedures is lacking. Twenty-four healthy/asymptomatic participants received a total of six SMT applications, representing all combinations of two similar SMT procedures within three patient hip flexion angles. All contact forces, patient torso kinematics, and inertial properties were entered into a dynamic three-dimensional LSM to calculate lumbar reaction forces and moments. Peak net applied force along with the maximums, minimums, and ranges for each component of the three-dimensional reaction force and moment vectors during each SMT procedure was analyzed. One specific SMT technique (lumbar spinous pull) produced greater maximum anterior-posterior reaction force and both lateral bending and axial twisting reaction moments compared to the other technique (lumbar push procedure [all P ≤ 0.034]). SMT trials without hip flexion had lower maximum medial-lateral reaction force and range compared to those with 45 and 90 degrees of hip flexion (all P ≤ 0.041). There were no interactions between procedure and hip angle for any of the dependent measurements. The technique used to apply SMT and the participant's initial hip orientation induced significantly different actions on the low back. These findings and future research can improve patient outcomes and safety by informing clinicians on how to best use SMT given specific types of low back pain. 2.

  17. 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).

  18. 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

  19. A visible light-induced photocatalytic silver enhancement reaction for gravimetric biosensors.

    PubMed

    Ko, Wooree; Yim, Changyong; Jung, Namchul; Joo, Jinmyoung; Jeon, Sangmin; Seo, Hyejung; Lee, Soo Suk; Park, Jae Chan

    2011-10-07

    We have developed a novel microgravimetric immunosensor using a WO(3) nanoparticle-modified immunoassay and a silver enhancement reaction. When the nanoparticles in silver ion solution (i.e.  AgNO(3)) are exposed to visible light, the silver ions are photocatalytically reduced and form a metallic silver coating on the nanoparticles. This silver coating consequently induces changes in the mass and light absorption spectrum. Although photocatalytic reduction reactions can be achieved using ultraviolet (UV) light and TiO(2) nanoparticles as described in our previous publication (Seo et al 2010 Nanotechnology 21 505502), the use of UV light in biosensing applications has drawbacks in that UV light can damage proteins. In addition, conventional quartz crystal substrates must be passivated to prevent undesirable silver ion reduction on their gold-coated sensing surfaces. We addressed these problems by adopting a visible light-induced photocatalytic silver enhancement method using WO(3) nanoparticles and lateral field excited (LFE) quartz crystals. As a proof-of-concept demonstration of the technique, streptavidin was adsorbed onto an LFE quartz crystal, and its mass was enhanced with biotinylated WO(3) nanoparticles, this being followed by a photocatalytic silver enhancement reaction. The mass change due to the enhancement was found to be > 30 times greater than the mass change obtained with the streptavidin alone.

  20. UV-Induced [2+2] Grafting-To Reactions for Polymer Modification of Cellulose.

    PubMed

    Conradi, Matthias; Ramakers, Gijs; Junkers, Thomas

    2016-01-01

    Benzaldehyde-functional cellulose paper sheets have been synthesized via tosylation of cellulose (Whatman No 5) followed by addition of p-hydroxy benzaldehyde. Via UV-induced Paterno-Büchi [2+2] cycloaddition reactions, these aldehyde functional surfaces are grafted with triallylcyanurate, trimethylolpropane allyl ether, and vinyl chloroacetate. In the following, allyl-functional polymers (poly(butyl acrylate), pBA, Mn = 6990 g mol(-1) , Đ = 1.12 and poly(N-isopropyl acrylamide), pNIPAAm, Mn = 9500 g mol(-1) , Đ = 1.16) synthesized via reversible addition fragmentation chain transfer polymerization are conjugated to the celloluse surface in a UV-induced grafting-to approach. With pBA, hydrophobic cellulose sheets are obtained (water contact angle 116°), while grafting of pNIPAAm allows for generation of "smart" surfaces, which are hydrophilic at room temperature, but that become hydrophobic when heated above the characteristic lower critical solution temperature (93° contact angle). The Paterno-Büchi reaction has been shown to be a versatile synthetic tool that also performs well in grafting-to approaches whereby its overall performance seems to be close to that of radical thiol-ene reactions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Typical antimicrobials induce mast cell degranulation and anaphylactoid reactions via MRGPRX2 and its murine homologue MRGPRB2.

    PubMed

    Zhang, Tao; Che, Delu; Liu, Rui; Han, Shengli; Wang, Nan; Zhan, Yingzhuan; Pundir, Priyanka; Cao, Jiao; Lv, Yanni; Yang, Liu; Wang, Jue; Ding, Meiwen; Dong, Xinzhong; He, Langchong

    2017-07-08

    Mast cells are unique immune cells that function as sentinels in host defence reactions, including immediate hypersensitivity responses and allergic responses. The mast cell-specific receptor named MAS-related G protein-coupled receptor X2 (MRGPRX2) triggers mast-cell degranulation, a key process in anaphylactoid reactions. It is widely observed that antimicrobials can induce pseudo-allergic reactions (i.e. IgE-independent mechanism) with symptoms ranging from skin inflammation to life-threatening systemic anaphylaxis. However, their direct involvement and the mechanisms underlying anaphylactoid reactions caused by antimicrobials have not been demonstrated. Structurally different antimicrobials were screened by Ca(2+) imaging using MRGPRX2 overexpressing HEK293 cells. MRGPRX2 related anaphylactoid reactions induced by these components were investigated by body temperature drop and mast cell degranulation assays. We showed that MRGPRX2 is involved in allergic-like reactions to three types of antimicrobials in a dose-dependent manner. However, mast cells lacking the receptor show reduced degranulation. Furthermore, mice without MAS-related G protein-coupled receptor B2 (the orthologous gene of MRGPRX2) exhibited reduced substance-induced inflammation. Interestingly, β-lactam and antiviral nucleoside analogues did not induce anaphylactic reactions, which were also observed in vitro. These results should alarm many clinicians that such drugs might induce anaphylactoid reactions and provide guidance on safe dosage of these drugs. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. 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*.

  3. 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

  4. Effect of ^{12}C+α clustering on the E0 transition in ^{16}O

    NASA Astrophysics Data System (ADS)

    Matsuno, H.; Itagaki, N.; Ichikawa, T.; Yoshida, Y.; Kanada-En'yo, Y.

    2017-06-01

    We investigate cluster structures and E0 transitions of 0^+ states in ^{16}O. In particular, we discuss the mixing effect of 3α and α breaking components in the ^{12}C cluster on the E0 transitions. To this end, we perform a microscopic calculation including α cluster and cluster-breaking model spaces. By analyzing the obtained results, we confirm that the 0_2^+ and 0_3^+ states of ^{16}O are indeed the weak-coupling ^{12}C(0^+)+α and ^{12}C(2^+)+α cluster states, respectively. We find mainly two important mechanisms for reducing the E0 transition: (i) the difference in intrinsic spin configurations between the initial and final states caused by the cluster breaking and (ii) the mixing of planar 4α configurations in the excited states. We show that the E0 operator excites the initial (ground) state not to planar 4α configurations but predominantly to triangular pyramid 4α configurations. Thus, the mixture of the planar 4α configurations in the 0_2^+ state significantly reduces the E0 transition matrix elements to this state. We conclude that the E0 transitions tend to be enhanced by cluster states, but they are affected by various mechanisms originating in the detailed structures of the final states.

  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. Pre-equilibrium emission and clustering in medium-mass nuclei: 46Ti from 16O + 30Si, 18O + 28Si, 19F + 27Al

    NASA Astrophysics Data System (ADS)

    Cicerchia, M.; Marchi, T.; Gramegna, F.; Cinausero, M.; Mabiala, J.; Fabris, D.; Caciolli, A.; Collazzuol, G.; Mengoni, D.; Degerlier, M.; Morelli, L.; Bruno, M.; D'Agostino, M.; Barlini, S.; Bini, M.; Pasquali, G.; Piantelli, S.; Casini, G.; Pastore, G.; Gruyer, D.; Ottanelli, P.; Valdrè, S.; Gelli, N.; Olmi, A.; Poggi, G.; Vardaci, E.; Lombardo, I.; Dell'Aquila, D.; Leoni, S.; Cieplicka, N.; Fornal, B.

    2017-06-01

    The study of nuclear cluster states bound by valence neutrons is a field of recent large interest. In particular, it is interesting to study the pre-formation of α-clusters in α-conjugate nuclei and the dynamical condensation of clusters during nuclear reactions. The NUCL-EX collaboration (INFN, Italy) is carrying out a research campaign studying pre-equilibrium emission of light charged particles and cluster properties of light and medium-mass nuclei. For this purpose, a comparative study of the three nuclear reactions: 16O + 30Si, 18O + 28Si and 19F + 27Al, has been recently carried out using the GARFIELD+RCo 4π setup. After a general introduction on the experimental campaign, the preliminary results for the three systems are presented.

  7. 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.

  8. 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.

  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. 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.

  11. 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

  12. Enzymatic reactions in liposomes using the detergent-induced liposome loading method.

    PubMed

    Oberholzer, T; Meyer, E; Amato, I; Lustig, A; Monnard, P A

    1999-01-12

    Microcompartmentalization is a crucial step in the origin of life. More than 30 years ago, Oparin et al. proposed models based on biochemical reactions taking place in so-called coacervates. Their intention was to develop systems with which semipermeable microcompartments could be established. In the present work we follow their intuition, but we use well-characterized bilayer structures instead of the poorly characterized coacervates. Liposomes from phospholipids can be used as microreactors but they exhibit only a modest permeability and, therefore, chemical reactions occurring inside these structures are depleted after a relatively short period. Here it is shown that even highly stable liposomes from 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) can be used as semipermeable microreactors when treated with sodium cholate. Using this kind of mixed liposomes, we describe a biochemical reaction occurring inside the liposomes while the same reaction is prevented in the external medium. In addition, we show that this cholate-induced permeability of POPC bilayers can even be used to load macromolecules such as enzymes from the outside.

  13. 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.

  14. 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

  15. The enzymatic reaction-induced configuration change of the prosthetic group PQQ of methanol dehydrogenase.

    PubMed

    Li, Jie; Gan, Jian-Hua; Mathews, F Scott; Xia, Zong-Xiang

    2011-03-25

    Methanol dehydrogenase is a heterotetrameric enzyme containing the prosthetic group pyrroloquinoline quinone (PQQ), which catalyzes the oxidation of methanol to formaldehyde. The crystal structure of methanol dehydrogenase from Methylophilus W3A1, previously determined at high resolution, exhibits a non-planar configuration of the PQQ ring system and lends support for a hydride transfer mechanism of the enzymatic reaction catalyzed by the enzyme. To investigate why PQQ is in the C5-reduced form and to better understand the catalytic mechanism of the enzyme, three structures of this enzyme in a new crystal form have been determined at higher resolution. Two of the three crystals were grown in the presence of 1 and 50 mM methanol, respectively, both structures of which show non-planar configurations of the PQQ ring system, confirming the previous conclusion; the other was crystallized in the presence of 50 mM ethanol, the structure of which displays a planar ring system for PQQ. Comparison of these structures reveals that the configuration change of PQQ is induced by the enzymatic reaction. The reaction takes place and the C5-reduced PQQ intermediate is produced when the enzyme co-crystallizes with methanol, but the enzymatic reaction does not take place and the PQQ ring retains a planar configuration of the oxidized orthoquinone form when ethanol instead of methanol is present in the crystallization solution. Copyright © 2011 Elsevier Inc. All rights reserved.

  16. Calculated differential and double differential cross section of DT neutron induced reactions on natural chromium (Cr)

    NASA Astrophysics Data System (ADS)

    Rajput, Mayank; Vala, Sudhirsinh; Srinivasan, R.; Abhangi, M.; Subhash, P. V.; Pandey, B.; Rao, C. V. S.; Bora, D.

    2017-07-01

    Chromium is an important alloying element of stainless steel (SS) and SS is the main constituent of structural material proposed for fusion reactors. Energy and double differential cross section data will be required to estimate nuclear responses in the materials used in fusion reactors. There are no experimental data of energy and double differential cross section, available for neutron induced reactions on natural chromium at 14 MeV neutron energy. In this study, energy and double differential cross section data of (n,p) and (n,α) reactions for all the stable isotopes of chromium have been estimated, using appropriate nuclear models in TALYS code. The cross section data of stable isotopes are later converted into the energy and double differential cross section data of natural Cr using the isotopic abundance. The contribution from compound, pre-equilibrium and direct nuclear reaction to total reaction have also been calculated for 52,50Cr(n,p) and 52Cr(n,α). The calculation of energy differential cross section shows that most of emitted protons and alpha particles are of 3 and 8 MeV respectively. The calculated data is compared with the data from EXFOR data library and is found to be in good agreement.

  17. 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.

  18. 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.

  19. Hapten-Induced Contact Hypersensitivity, Autoimmune Reactions, and Tumor Regression: Plausibility of Mediating Antitumor Immunity

    PubMed Central

    Erkes, Dan A.; Selvan, Senthamil R.

    2014-01-01

    Haptens are small molecule irritants that bind to proteins and elicit an immune response. Haptens have been commonly used to study allergic contact dermatitis (ACD) using animal contact hypersensitivity (CHS) models. However, extensive research into contact hypersensitivity has offered a confusing and intriguing mechanism of allergic reactions occurring in the skin. The abilities of haptens to induce such reactions have been frequently utilized to study the mechanisms of inflammatory bowel disease (IBD) to induce autoimmune-like responses such as autoimmune hemolytic anemia and to elicit viral wart and tumor regression. Hapten-induced tumor regression has been studied since the mid-1900s and relies on four major concepts: (1) ex vivo haptenation, (2) in situ haptenation, (3) epifocal hapten application, and (4) antigen-hapten conjugate injection. Each of these approaches elicits unique responses in mice and humans. The present review attempts to provide a critical appraisal of the hapten-mediated tumor treatments and offers insights for future development of the field. PMID:24949488

  20. [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.

  1. Carbamazepine-induced severe cutaneous adverse reactions and HLA genotypes in Koreans.

    PubMed

    Kim, Sae-Hoon; Lee, Kyung Wha; Song, Woo-Jung; Kim, Sang-Heon; Jee, Young-Koo; Lee, Sang-Min; Kang, Hye-Ryun; Park, Heung-Woo; Cho, Sang-Heon; Park, Seong-Ho; Min, Kyung-Up; Chang, Yoon-Seok

    2011-11-01

    Although the US FDA recommends screening for HLA-B*1502 allele in most of Asian ancestry before initiating carbamazepine therapy, the HLA associations with carbamazepine hypersensitivity in non-Chinese Asian populations remain unclear. This study investigated the association between the HLA class I genotype and carbamazepine-induced severe cutaneous adverse reaction (SCAR) in Koreans. Twenty-four patients who had developed carbamazepine-induced SCAR (7 Stevens-Johnson syndrome (SJS), 17 drug hypersensitivity syndrome (HSS)), 50 carbamazepine-tolerant controls from the Korean Pharmacogenetic Adverse Drug Reaction Research Network and data of 485 Korean general population from a previously published study were recruited. HLA-A, -B, and -C genotyping was performed by direct DNA sequence analysis. Only one of the seven SJS patients was positive for the B*1502 allele, but the frequency of B*1511 was much higher in the patients with CBZ-SJS than in the CBZ-tolerant control patients (P=0.011, P(c)=not significant; OR=18.0(2.3-141.2)). The frequencies of A*3101 in carbamazepine-induced HSS and SCAR were significantly higher than those in carbamazepine-tolerant controls (P(c)=0.011, OR=8.8(2.5-30.7) and P(c)=0.013, OR=7.3(2.3-22.5), respectively). The frequencies of B*1511 in carbamazepine-SJS and A*3101 in carbamazepine-HSS/SCAR were significantly higher than those in the general population. HLA-B*1502 does not seem to be an effective predictive marker for carbamazepine-induced SCAR, while HLA-B*1511 and A*3101 was associated with carbamazepine-induced SJS and HSS/SCAR respectively in the Korean population. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. 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.

  3. Experimental study and nuclear model calculations of 3He-induced nuclear reactions on zinc

    NASA Astrophysics Data System (ADS)

    Al-Abyad, M.; Mohamed, Gehan Y.; Ditrói, F.; Takács, S.; Tárkányi, F.

    2017-05-01

    Excitation functions of 3He -induced nuclear reactions on natural zinc were measured using the standard stacked-foil technique and high-resolution gamma-ray spectrometry. From their threshold energies up to 27MeV, the cross-sections for natZn (3He, xn) 69Ge, natZn(3He, xnp) 66,67,68Ga, and natZn(3He, x)62,65Zn reactions were measured. The nuclear model codes TALYS-1.6, EMPIRE-3.2 and ALICE-IPPE were used to describe the formation of these products. The present data were compared with the theoretical results and with the available experimental data. Integral yields for some important radioisotopes were determined.

  4. Proton and deuteron induced reactions on natGa: Experimental and calculated excitation functions

    NASA Astrophysics Data System (ADS)

    Hermanne, A.; Adam-Rebeles, R.; Tárkányi, F.; Takács, S.; Ditrói, F.

    2015-09-01

    Cross-sections for reactions on natGa, induced by protons (up to 65 MeV) and deuterons (up to 50 MeV), producing γ-emitting radionuclides with half-lives longer than 1 h were measured in a stacked-foil irradiation using thin Ga-Ni alloy (70-30%) targets electroplated on Cu or Au backings. Excitation functions for generation of 68,69Ge, 66,67,68,72Ga and 65,69mZn on natGa are discussed, relative to the monitor reactions natAl(d,x)24,22Na, natAl(p,x)24,22Na, natCu(p,x)62Zn and natNi(p,x)57Ni. The results are compared to our earlier measurements, the scarce literature values and to the results of the code TALYS 1.6 (online database TENDL-2014).

  5. 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. PMID:28392649

  6. Neutrino-induced reactions and neutrino scattering with nuclei in low and high neutrino energy

    SciTech Connect

    Cheoun, Myung-Ki Ha, Eunja; Yang, Ghil-Seok; Kim, K. S.; Kajino, T.

    2016-06-21

    We reviewed present status regarding theoretical approaches for neutrino-induced reactions and neutrino scattering. With a short introduction of relevant data, our recent calculations by distorted-wave Born approximation (DWBA) for quasielastic region are presented for MiniBooNE data. We also discussed that one step-process estimated by the DWBA is comparable to the two-step process, which has been usually used in the neutrino-nucleosynthesis. For much higher energy neutrino data, such as NOMAD data, elementary process approach was shown to be useful instead of using complicated nuclear models. But, in the low energy region, detailed nuclear structure model, such as QRPA and shell model, turn out to be inescapable to explain the reaction data.

  7. 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.

  8. 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.

  9. 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.

  10. Diagnostic patch testing following tuberculosis-associated cutaneous adverse drug reactions induces systemic reactions in HIV-infected persons.

    PubMed

    Lehloenya, R J; Todd, G; Wallace, J; Ngwanya, M R; Muloiwa, R; Dheda, K

    2016-07-01

    The incidence of cutaneous adverse drug reactions (CADRs) to first-line antituberculosis drugs (FLTDs) is higher in HIV-tuberculosis coinfection. However, the utility of patch testing to identify the offending drug in this patient subgroup has been poorly studied. To identify drugs causing adverse drug reactions in patients with HIV-tuberculosis coinfection. Fourteen consecutive patients underwent diagnostic work-up (patch testing followed by a skin prick test and an oral rechallenge) to pinpoint the offending drug after developing FLTD-associated CADR, which included drug rash with eosinophilia and systemic symptoms (n = 12), Stevens-Johnson syndrome (SJS, n = 1) and toxic epidermal necrolysis/SJS overlap (n = 1). A positive reaction to any of the three diagnostic modalities eliminated that drug from the regimen. Once patients were clinically stable postreaction, sequential and additive rechallenge with FLTDs was initiated. Eleven of the 14 participants with FLTD-associated CADR were HIV infected (median CD4 count 149 cells mm(-3) ). In this subgroup, patch testing resulted in generalized systemic reactions in 10 of 11 patients (91%). These included rash in 10 of 13 reactions (77%), eosinophilia in eight (62%), transaminitis in seven (54%) and fever in five (38%). Isoniazid caused six of 13 (46%) generalized systemic reactions, rifampicin four (31%), ethambutol two (15%) and pyrazinamide one reaction. Using the Common Terminology Criteria for Adverse Events, five of 13 reactions were mild, six were moderate and two were severe. There were no life-threatening or fatal reactions. In HIV-infected persons with tuberculosis-associated CADR, although patch-testing reactions to FLTD are common and tend to be associated with systemic features, they are not life threatening or fatal. These data inform clinical practice in HIV-endemic settings. © 2016 British Association of Dermatologists.

  11. 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)

  12. 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.

  13. Role of defective methylation reactions in ethanol-induced dysregulation of intestinal barrier integrity.

    PubMed

    Thomes, Paul G; Osna, Natalia A; Bligh, Sarah M; Tuma, Dean J; Kharbanda, Kusum K

    2015-07-01

    Alcoholic liver disease (ALD) is a major healthcare challenge worldwide. Emerging evidence reveals that ethanol administration disrupts the intestinal epithelial tight junction (TJ) complex; this defect allows for the paracellular translocation of gut-derived pathogenic molecules to reach the liver to cause inflammation and progressive liver injury. We have previously demonstrated a causative role of impairments in liver transmethylation reactions in the pathogenesis of ALD. We have further shown that treatment with betaine, a methylation agent that normalizes liver methylation potential, can attenuate ethanol-induced liver injury. Herein, we explored whether alterations in methylation reactions play a causative role in disrupting intestinal mucosal barrier function by employing an intestinal epithelial cell line. Monolayers of Caco-2 cells were exposed to ethanol or a-pan methylation reaction inhibitor, tubercidin, in the presence and absence of betaine. The structural and functional integrity of intestinal epithelial barrier was then examined. We observed that exposure to either ethanol or tubercidin disrupted TJ integrity and function by decreasing the localization of TJ protein occludin-1 to the intracellular junctions, reducing transepithelial electrical resistance and increasing dextran influx. All these detrimental effects of ethanol and tubercidin were attenuated by co-treatment with betaine. We further show that the mechanism of betaine protection was through BHMT-mediated catalysis. Collectively, our data suggest a novel mechanism for alcohol-induced gut leakiness and identifies the importance of normal methylation reactions in maintaining TJ integrity. We also propose betaine as a potential therapeutic option for leaky gut in alcohol-consuming patients who are at the risk of developing ALD. Published by Elsevier Inc.

  14. Enhancement of nitrite on heme-induced oxidative reactions: A potential toxicological implication.

    PubMed

    Lu, Naihao; Chen, Wei; Zhu, Jingjie; Peng, Yi-Yuan

    2012-02-01

    Evidence to support the role of heme as major inducers of oxidative damage is increasingly present. Nitrite (NO(2)(-)) is one of the major end products of NO metabolism. Although the biological significance of heme/NO(2)(-)-mediated protein tyrosine nitration is a subject of great interest, the important roles of NO(2)(-) on heme-dependent redox reaction have been greatly underestimated. In this study, we investigated the influence of NO(2)(-) on heme -dependent oxidative reactions. It was found that NO(2)(-) had the capacity to act as a reducing agent to remove high oxidation states of heme iron. In the reduction of ferryl heme to ferric heme, NO(2)(-) was oxidized to a nitrating agent NO(2), and subsequently, tyrosine residues in bovine serum albumin (BSA) were nitrated. However, the presence of NO(2)(-) surprisingly exerted pro-oxidant effect on heme-H(2)O(2)-induced formation of BSA carbonyls at lower concentrations and enhanced the loss of HepG2 cell viability dose-dependently, which was probably due to the ability of this inorganic compound to efficiently enhance the peroxidase activity and oxidative degradation of heme. These data provide novel evidence that the dietary intake and experimental use of NO(2)(-) in vivo and in vitro would possess the pro-oxidant activity through interfering in heme-dependent oxidative reactions. Besides the classic role in protein tyrosine nitration, the deleterious effects on heme redox reactions may provide new insights into the toxicological implications of NO(2)(-) with cellular heme proteins. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. 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.

  16. Modeling dune-induced hyporheic exchange and nutrient reactions in stream sediments

    NASA Astrophysics Data System (ADS)

    Bardini, L.; Boano, F.; Cardenas, M. B.; Revelli, R.; Ridolfi, L.

    2012-04-01

    The exchange of water across the streambed plays an important role in the ecology of fluvial environments, since it assures the connections of surface and subsurface waters, which have very different peculiarities. Water-borne chemicals are also involved in the process: they enter the sediments with the water and they are transformed into oxidized or reduced substances by biogeochemical reactions, mediated by the hyporheic microbiota. In particular, organic substances can be used as electron donors in a series of redox reactions, with different electron acceptors, e.g., oxygen and nitrate. Nitrification and other secondary reactions also occur as soon as water enters the streambed. These pore-scale transformations concur to affect subsurface solute concentrations and, consequently, the chemistry of upwelling water and the quality of the stream environment. The exchange with the hyporheic zone occurs in response to variations in bed topography, with a very wide range of spatial and temporal scales. For instance, small-scale exchanges are mainly induced by river bed forms, like ripples and dunes, while large-scale exchanges depend on larger geomorphological features. In this work we focus on small-scale exchange induced by the presence of dunes on the streambed, investigating the interplay of hydrological and biogeochemical processes and their effects on solute spatial distribution in the sediments. We numerically simulate the turbulent water flow and the pressure distribution on the streambed and then we evaluate the coupled flow field and biogeochemical reactions in the hyporheic zone in steady-state conditions. Four representative reactive compounds are taken into account: dissolved organic carbon (DOC), oxygen (O2), nitrate (NO3-) and ammonium (NH4+). Sensitivity analyses are also performed to analyze the influence of hydrological and chemical properties of the system on solute reaction rates. The results demonstrate that the stream water quality can strongly

  17. Local chemical reaction of benzene on Cu110 via STM-induced excitation.

    PubMed

    Komeda, T; Kim, Y; Fujita, Y; Sainoo, Y; Kawai, Maki

    2004-03-15

    We have investigated the mechanism of the chemical reaction of the benzene molecule adsorbed on Cu(110) surface induced by the injection of tunneling electrons using scanning tunneling microscopy (STM). With the dosing of tunneling electrons of the energy 2-5 eV from the STM tip to the molecule, we have detected the increase of the height of the benzene molecule by 40% in the STM image and the appearance of the vibration feature of the nu(C-H) mode in the inelastic tunneling spectroscopy (IETS) spectrum. It can be understood with a model in which the dissociation of C-H bonds occurs in a benzene molecule that induces a bonding geometry change from flat-lying to up-right configuration, which follows the story of the report of Lauhon and Ho on the STM-induced change of benzene on the Cu(100) surface. [L. J. Lauhon and W. Ho, J. Phys. Chem. A 104, 2463 (2000)]. The reaction probability shows a sharp rise at the sample bias voltage at 2.4 V, which saturates at 3.0 V, which is followed by another sharp rise at the voltage of 4.3 V. No increase of the reaction yield is observed for the negative sample voltage up to 5 eV. In the case of a fully deuterated benzene molecule, it shows the onset at the same energy of 2.4 eV, but the reaction probability is 10(3) smaller than the case of the normal benzene molecule. We propose a model in which the dehydrogenation of the benzene molecule is induced by the formation of the temporal negative ion due to the trapping of the electrons at the unoccupied resonant states formed by the pi orbitals. The existence of the resonant level close to the Fermi level ( approximately 2.4 eV) and multiple levels in less than approximately 5 eV from the Fermi level, indicates a fairly strong interaction of the Cu-pi(*) state of the benzene molecule. We estimated that the large isotope effect of approximately 10(3) can be accounted for with the Menzel-Gomer-Redhead (MGR) model with an assumption of a shallow potential curve for the excited state. (c

  18. Micropatterning of Ferroelectric Thin Films by Electron-Beam-Induced Reaction Process

    NASA Astrophysics Data System (ADS)

    Fujii, Tadashi; Matsunaga, Hiroaki; Adachi, Masatoshi

    2008-01-01

    The micropatterning of ferroelectric thin films is a valuable technology for realizing high-density ferroelectric random access memories, sensors and actuators. We fabricated 500-nm- to 20-µm-sized circular dots of (Pb,Sr)TiO3 micropatterns by an electron-beam-induced reaction process using a scanning-electron-microscope-based electron beam lithography system. The piezoelectric response was observed in 10-µm-sized dots by piezoresponse scanning force microscopy. Using an atomic force microscope, every fabricated dot pattern was found to have a mesa shape. To obtain 100-nm-sized dots with high density, further optimization of EB irradiation and crystallization conditions is necessary.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. Visible-light induced isoindoles formation to trigger intermolecular Diels-Alder reactions in the presence of air.

    PubMed

    Lin, Chao; Zhen, Le; Cheng, Yong; Du, Hong-Jin; Zhao, Hui; Wen, Xiaoan; Kong, Ling-Yi; Xu, Qing-Long; Sun, Hongbin

    2015-06-05

    Visible-light induced isoindole formation triggered an intermolecular Diels-Alder reaction with dienophiles such as acetylenedicarboxylate and maleimides in the presence of air. The reaction resulted in excellent diastereoselctivity and high yields under mild reaction conditions. This protocol provides an atom-economical, transition-metal-free (TM-free) and straightforward approach to structurally diverse bridged-ring heterocycles from easily accessible molecules.

  5. Photo-induced coupling reactions of tetrazoles with carboxylic acids in aqueous solution: application in protein labelling.

    PubMed

    Zhao, Shan; Dai, Jianye; Hu, Mo; Liu, Chang; Meng, Rong; Liu, Xiaoyun; Wang, Chu; Luo, Tuoping

    2016-03-28

    The photo-induced reactions of diaryltetrazoles with carboxylic acids in aqueous solution were investigated. Besides measuring the apparent second-order rate constant and evaluating the functional group compatibility of these reactions, we further incorporated the tetrazoles into SAHA, leading to a new active-site-directed probe for labelling HDACs in both cell lysates and living cells.

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

    SciTech Connect

    Guardo, G. L.; Lamia, L.; Spitaleri, C.; Cherubini, S.; Rapisarda, G. G.; Sergi, M. L.; Gulino, M.; Tang, X. D.; Bucher, B.; Couder, M.; Davies, P.; Boer, R. de; Fang, X.; Lamm, L.; Ma, C.; Notani, M.; OBrien, S.; Roberson, D.; Tan, W.; Wiescher, M.; and others

    2014-05-02

    The experimental study of the {sup 17}O(n,α){sup 14}C 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 {sup 17}O(n,α){sup 14}C reaction has been studied using the quasi-free {sup 2}H({sup 17}O,α{sup 14}C){sup 1}H 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, J{sup π}=5{sup −}), absent in the available direct measurements because of centrifugal suppression effects.

  7. The 18F(n,α ) Reaction: First Study of n-Induced Reaction on a Radioactive Nucleus Using the Trojan Horse Method

    NASA Astrophysics Data System (ADS)

    Gulino, Marisa; Cherubini, Silvio; Spitaleri, Claudio; Rapisarda, Giuseppe Gabriele; La Cognata, Marco; Lamia, Livio; Gianluca Pizzone, Rosario; Romano, Stefano; Kubono, Shigeru; Yamaguchi, Hidetoshi; Hayakawa, Seya; Wakabayashi, Yasuo; Iwasa, Naohito; Kato, Seigo; Komatsubara, Tetsuro; Teranishi, Takashi; Coc, Alain; de Séréville, Nicolas; Hammache, Fairouz; Kiss, Gabor; Bishop, Shawn; Nguyen Binh, Dam

    For the first time the Trojan Horse Method was applied to infer information about a neutron induced reaction on a radioactive nucleus at low energies relevant for astrophysics. In particular, the 18F(n, α )15N reaction has been studied by using the 18F+d reaction. A 18F beam was produced at the CRIB facility at RIKEN, Japan, and was focused onto a CD2 target. The beam had energy of 48 MeV, an average intensity of 105 pps and an average purity of 80%. A new designed experimental set-up covering a large solid angle was used to detect the ejected particles. The reaction cross section has been for the first time investigated in the energy range from 0 up to 2.5 MeV and several resonant states of 19F have been populated.

  8. 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.

  9. 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. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. 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

  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. Shock-induced hotspot formation and chemical reaction initiation in PETN containing a spherical void

    NASA Astrophysics Data System (ADS)

    Shan, Tzu-Ray; Thompson, Aidan P.

    2014-05-01

    We present results of reactive molecular dynamics simulations of hotspot formation and chemical reaction initiation in shock-induced compression of pentaerythritol tetranitrate (PETN) with the ReaxFF reactive force field. A supported shockwave is driven through a PETN crystal containing a 20 nm spherical void at a sub-threshold impact velocity of 2 km/s. Formation of a hotspot due to shock-induced void collapse is observed. During void collapse, NO2 is the dominant species ejected from the upstream void surface. Once the ejecta collide with the downstream void surface and the hotspot develops, formation of final products such as N2 and H2O is observed. The simulation provides a detailed picture of how void collapse and hotspot formation leads to initiation at sub-threshold impact velocities.

  13. 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.

  14. Induced Polarization in the 2H(gamma,n)p Reaction at Low Energy

    SciTech Connect

    Rocco Schiavilla

    2005-05-01

    The induced polarization, P{prime}{sub y}, of the neutron in the deuteron photo-disintegration from threshold up to 30 MeV is calculated using a variety of different, latest-generation potentials--Argonne v{sub 18}, Bonn 2000, and Nijmegen I--and a realistic model for the nuclear electromagnetic current operator, including one- and two-body terms. The model dependence of the theoretical predictions is found to be very small. These predictions are systematically larger in magnitude than the measured P{prime}{sub y} values, and corroborate the conclusions of an earlier, and much older, study. There is considerable scatter in the available experimental data. New and more accurate measurements of the induced polarization in the {sup 2}H({gamma},{rvec n}){sup 1}H reaction are needed in order to establish unequivocally whether there is a discrepancy between theory and experiment.

  15. 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.

  16. Candidate HLA genes for prediction of co-trimoxazole-induced severe cutaneous reactions.

    PubMed

    Kongpan, Thachanan; Mahasirimongkol, Surakameth; Konyoung, Parinya; Kanjanawart, Sirimas; Chumworathayi, Pansu; Wichukchinda, Nuanjun; Kidkeukarun, Runglak; Preechakul, Suphanlinee; Khunarkornsiri, Usanee; Bamrungram, Warawut; Supharatwattanakun, Butsaban; Mootsikapun, Piroon; Kwangsukstid, Supanida; Denjanta, Sukanda; Vannaprasaht, Suda; Rungapiromnan, Watcharee; Suwankesawong, Wimon; Tassaneeyakul, Wongwiwat; Tassaneeyakul, Wichittra

    2015-08-01

    Co-trimoxazole is a sulfonamide-containing antibiotic that is effective in the treatment of several infections and for prophylaxis of Pneumocystis jiroveci pneumonia. This drug has been reported as a common culprit drug for the Stevens-Johnson syndrome (SJS) and for toxic epidermal necrolysis (TEN). Human leukocyte antigens (HLAs) play a key role in the immunopathogenesis of severe cutaneous reactions induced by several drugs. This study investigated the association between the HLA class I and HLA-DRB1 polymorphisms and co-trimoxazole-induced SJS/TEN in a Thai population. Forty-three patients with co-trimoxazole-induced SJS/TEN and 91 co-trimoxazole-tolerant patients were enrolled in the study. HLA class I and HLA-DRB1 were genotyped using the reverse sequence-specific oligonucleotide probe method. The frequencies of three alleles of HLA, namely HLA-B*15:02, HLA-C*06:02, and HLA-C*08:01, were significantly higher in the co-trimoxazole-induced SJS/TEN group compared with controls. The risks for co-trimoxazole-induced SJS/TEN in patients with the HLA-B*15:02, HLA-C*06:02, or HLA-C*08:01 allele were about 3-11-fold higher when compared with those who did not carry one of these alleles. Individuals who carried the HLA-B*15:02-C*08:01 haplotype had a 14-fold higher risk for co-trimoxazole-induced SJS/TEN. Evidence of associations between co-trimoxazole-induced SJS/TEN and HLA alleles including HLA-B*15:02, HLA-C*06:02, and HLA-C*08:01 were found in the study population. These findings may suggest that apart from the HLA molecules, other molecules involved in the molecular pathogenesis of these severe cutaneous adverse drug reactions may play an important role in the susceptibility of individuals to SJS/TEN caused by co-trimoxazole.

  17. 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.

  18. β-delayed α decay of {sup 16}N and the {sup 12}C(α,γ){sup 16}O cross section at astrophysical energies: A new experimental approach

    SciTech Connect

    Sanfilippo, S.; Cherubini, S.; Lattuada, M.; Spitaleri, C.; Hayakawa, S.; Di Pietro, A.; Figuera, P.; La Cognata, M.; Gulino, M.; Yamaguchi, H.; Kahl, D.; Nakao, T.; Kubono, S.; Wakabayashi, Y.; Hashimoto, T.; Iwasa, N.; Okoda, Y.; Ushio, K.; Teranishi, T.; Mazzocco, M.; and others

    2015-02-24

    The {sup 12}C(α,γ){sup 16}O reaction at energies corresponding to the quiescent helium burning in massive stars is regarded as one of the most important processes in nuclear astrophysics. Although this process has being studied for over four decades, our knowledge of its cross section at the energies of interest for astrophysics is still widely unsatisfactory. Indeed, no experimental data are available around 300 keV and in the energy region of astrophysical interest extrapolations are performed using some theoretical approaches, usually R-matrix calculations. Consequently, the published astrophysical factors range from 1 to 288 keVb for S{sub E1}(300) and 7 to 120 keVb for S{sub E2}(300), especially because of the unknown contribution coming from subthreshold resonances. To improve the reliability of these extrapolations, data from complementary experiments, such as elastic and quasi- elastic α scattering on {sup 12}C, α-transfer reactions to {sup 16}O, and {sup 16}N decay are usually included in the analysis. Here the β-delayed α decay of {sup 16}N is used to infer information on the {sup 12}C(α,γ){sup 16}O reaction and a new experimental technique is suggested.

  19. Fragmentation cross sections of 16O between 0.9 and 200 GeV/nucleon

    NASA Technical Reports Server (NTRS)

    Hirzebruch, S. E.; Heinrich, W.; Tolstov, K. D.; Kovalenko, A. D.; Benton, E. V.

    1992-01-01

    Inclusive cross sections for high energy interactions at 0.9, 2.3, 3.6, and 13.5 GeV/nucleon of 16O with C, CR-39 (C12H18O7), CH2, Al, Cu, Ag, and Pb targets were measured. The total charge-changing cross sections and partial charge-changing cross sections for the production of fragments with charge Z = 6 and Z = 7 are compared to previous experiments at 60 and 200 GeV/nucleon. The contributions of Coulomb dissociation to the total cross sections are calculated. Using factorization rules the partial electromagnetic cross sections are separated from the nuclear components. Energy dependence of both components are investigated and discussed.

  20. 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.