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Sample records for 16o induced reactions

  1. Investigation of the role of break-up processes on the fusion of {sup 16}O induced reactions

    SciTech Connect

    Singh, Devendra P.; Unnati; Singh, Pushpendra P.; Yadav, Abhishek; Singh, B. P.; Prasad, R.; Sharma, Manoj Kumar; Golda, K. S.; Kumar, Rakesh; Sinha, A. K.

    2009-07-15

    An experiment was carried out to explore heavy ion incomplete fusion reaction dynamics, within the framework of the break-up fusion model, at energies near and above the Coulomb barrier. Excitation functions for several radionuclides produced via xn, pxn, and {alpha}xn channels were measured in the {sup 16}O+{sup 181}Ta system at energies of {approx_equal}76-100 MeV. The experimental excitation functions were compared with those calculated using the theoretical model code PACE4. It was observed that excitation functions of xn/pxn channels are in good agreement with theoretical predictions. However, a significant enhancement in the measured excitation functions of {alpha}-emitting channels was observed and attributed to the incomplete fusion processes. The incomplete fusion fraction (F{sub ICF}) that gives the relative importance of complete and incomplete fusion processes was found to increase with energy. The results are discussed in terms of {alpha}-cluster structure of the projectile on various fusion reactions.

  2. Two-neutron transfer analysis of the 16O(18O,16O)18O reaction

    NASA Astrophysics Data System (ADS)

    Ermamatov, M. J.; Cappuzzello, F.; Lubian, J.; Cubero, M.; Agodi, C.; Carbone, D.; Cavallaro, M.; Ferreira, J. L.; Foti, A.; Garcia, V. N.; Gargano, A.; Lay, J. A.; Lenzi, S. M.; Linares, R.; Santagati, G.; Vitturi, A.

    2016-08-01

    Recently a quantitative description of the two-neutron transfer reaction 12C(18O,16O)14C was performed and the measured cross sections were successfully reproduced [M. Cavallaro et al., Phys. Rev. C 88, 054601 (2013), 10.1103/PhysRevC.88.054601]. This task was accomplished by combining nuclear structure calculations of spectroscopic amplitudes and a full quantum description of the reaction mechanism. Verification of such a theoretical approach to other heavy nuclear systems is mandatory in order to use (18O,16O ) reactions to assess pair configurations in nuclear states. In this work we apply this methodology to the 16O(18O,16O)18O reaction at 84 MeV. Experimental angular distributions for the two-neutron transfer to the ground state and 21+ state of 18O were obtained using the MAGNEX spectrometer at INFN-LNS. The roles of one- and two-step processes are analyzed under the exact finite range coupled reaction channel and the second order distorted wave Born approximation. We conclude that the one-step transfer mechanism is dominant in this system.

  3. Transverse energy scaling and energy density estimates from sup 16 O- and sup 32 S-induced reactions

    SciTech Connect

    Not Available

    1989-01-01

    We discuss the dependence of transverse energy production on projectile mass, target mass, and on the impact parameter of the heavy ion reaction. The transverse energy is shown to scale with the number of participating nucleons. Various methods to estimate the attained energy density from the observed transverse energy are discussed. It is shown that the systematics of the energy density estimates suggest averages of 2--3 GeV/fm{sup 3} rather than the much higher values attained by assuming Landau-stopping initial conditions. Based on the observed scaling of the transverse energy, an initial energy density profile may be estimated. 14 refs., 4 figs.

  4. Transverse energy scaling and energy density estimates from /sup 16/O- and /sup 32/S-induced reactions

    SciTech Connect

    Awes, T.C.; Albrecht, R.; Baktash, C.; Beckmann, P.; Berger, F.; Bock, R.; Claesson, G.; Clewing, G.; Dragon, L.; Eklund, A.

    1989-01-01

    We discuss the dependence of transverse energy production on projectile mass, target mass, and on the impact parameter of the heavy ion reaction. The transverse energy is shown to scale with the number of participating nucleons. Various methods to estimate the attained energy density from the observed transverse energy are discussed. It is shown that the systematics of the energy density estimates suggest average of 2-3 GeV/fm/sup 3/ rather than the much higher values attained by assuming Landau-stopping initial conditions. Based on the observed scaling of the transverse energy, an initial energy density profile may be estimated. 11 refs., 4 figs.

  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. {gamma}-ray production by proton and {alpha}-particle induced reactions on {sup 12}C, {sup 16}O, {sup 24}Mg, and Fe

    SciTech Connect

    Belhout, A.; Kiener, J.; Coc, A.; Duprat, J.; Engrand, C.; Fitoussi, C.; Gounelle, M.; Lefebvre-Schuhl, A.; Sereville, N. de; Tatischeff, V.; Thibaud, J.-P.; Chabot, M.; Hammache, F.; Benhabiles-Mezhoud, H.

    2007-09-15

    {gamma}-ray production cross sections for proton and {alpha}-particle interactions with {sup 12}C, {sup 16}O, {sup 24}Mg, and Fe have been measured in the energy range 5-25 MeV with proton beams and 5-40 MeV with {alpha}-particle beams. Isotopically pure foils of {sup 24}Mg and foils of natural isotopical composition of C, MgO, and Fe have been used. {gamma}-ray angular distributions were obtained with five high-purity Ge detectors with bismuth germanate Compton shields placed at angles of 45 deg. to 157.5 deg. Cross sections for more than 50 different {gamma}-ray transitions were extracted, and for many of them no data have been published before. Comparison of present data with data available in the literature shows mostly good to excellent agreement. In addition to the production cross sections, high-statistics, low-background line shapes of the 4.438 MeV {sup 12}C {gamma} ray from inelastic scattering off {sup 12}C and spallation of {sup 16}O were obtained. Comparison with nuclear reaction calculations shows that these data place interesting constraints on nuclear reaction models.

  8. 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.

  9. Holmium target fragmentation induced by intermediate energy /sup 12/C and /sup 16/O ions

    SciTech Connect

    Kraus, R.H. Jr.

    1986-01-01

    Target fragment (40 < A < 180) production cross sections were measured using off-line gamma-ray spectroscopy for the interaction of 208 MeV /sup 12/C, 272 MeV /sup 16/O, 442 MeV/sup 12/C, 1020 MeV /sup 12/C, and 1635 MeV /sup 16/O with /sup 165/Ho. Target fragment isobaric yields were deduced from these measurements. Trans-target nuclides were identified for all reaction systems. Nuclides up to 4 Z-units above the target were identified for 208 MeV /sup 12/C and 272 MeV /sup 16/O induced reactions, to 3 Z-units above the target for 442 MeV /sup 12/C and 1020 MeC /sup 12/C induced reactions, and to 2 Z-units above the target for 1635 MeV /sup 16/O induced reactions. Fission was observed to decrease between 17 MeV/A and 37 MeV/A from 13% of the reaction cross section to 4% for /sup 12/C induced reactions. No fission contribution was observed for 1020 MeV /sup 12/C and 1635 MeV /sup 16/O induced interactions.

  10. Comparative analysis of anodized, implanted and sputtered tantalum oxide targets for the study of 16O+16O fusion reaction

    NASA Astrophysics Data System (ADS)

    Silva, H.; Cruz, J.; Redondo-Cubero, A.; Santos, C.; Fonseca, M.; Luis, H.; Jesus, A. P.

    2014-07-01

    Measuring the total cross section of a fusion reaction in the region of astrophysical interest, such as the 16O+16O fusion reaction, is a real challenge due the very small cross sections involved and the large number of possible exit channels. Taking into account these difficulties, the use of targets with known thickness, stoichiometry and minimal contamination that can withstand high beam currents is required. In this study, we report the comparison between three different types of targets for the study of this fusion reaction, such as anodized, implanted and sputtered tantalum oxide targets and the results show that the anodized and sputtered targets are more suitable for this study due to their higher oxygen density and to the formation of a stable oxide compound, tantalum pentoxide (Ta2O5).

  11. Astrophysical SE2 factor of the 12C(α, γ)16O reaction through the 12C(11B, 7Li)16O transfer reaction

    NASA Astrophysics Data System (ADS)

    Guo, B.; Du, X. C.; Li, Z. H.; Li, Y. J.; Pang, D. Y.; Su, J.; Yan, S. Q.; Fan, Q. W.; Gan, L.; Han, Z. Y.; Li, E. T.; Li, X. Y.; Lian, G.; Liu, J. C.; Pei, C. J.; Qiao, L. H.; Shen, Y. P.; Su, Y.; Wang, Y. B.; Zeng, S.; Zhou, Y.; Liu, W. P.

    2016-02-01

    The 12C(α, γ)16O reaction plays a key role in the evolution of stars with masses of M > 0.55 M⊙. At the Gamow peak (Ec.m. = 300 ke V, T9 = 0.2), the cross section of the 12C(α, γ)16O reaction is so small (about 10-17 barn) that the direct measurement in ground laboratory is not feasible with the existing technology. Up to now, the cross sections at lower energies can only be extrapolated from the data at higher energies. However, two subthreshold resonances, locating at Ex = 7.117 MeV and Ex = 6.917 MeV, make this extrapolation more complicated. In this work the 6.917 MeV subthreshold resonance in the 12C(α, γ)16O reaction was investigated via the 12C(11B, 7Li)16O reaction. The experiment was performed using the Q3D magnetic spectrograph at HI-13 tandem accelerator. We measured the angular distribution of the 12C(11B, 7Li)16O transfer reaction leading to the 6.917 MeV state. Based on DWBA analysis, we derived the square of ANC of the 6.917 MeV level in 16O to be (2.45± 0.28) ×1010 fm-1, with which the reduced-α width can be computed. Finally, we calculated the astrophysical SE2 factor of the 6.917 MeV resonance to be 67.6 ± 7.7 ke V b.

  12. R-Matrix Analysis of the 13C(α,n)16O Reaction

    NASA Astrophysics Data System (ADS)

    Kock, Arthur; Rogachev, Grigory

    2015-10-01

    The 13C(α,n)16O reaction plays a crucial role in the main s-process occurring in low-mass thermally-pulsing asymptotic giant branch (TP-AGB) stars, which produces about half of all nuclei heavier than iron. However, direct measurements of this reaction cross section near the Gamow-peak energy are currently not possible due to very small reaction cross sections. Additionally, available cross-section data at higher energy have some inconsistencies, leading to significant uncertainties in low energy extrapolations. A global R-matrix fit was conducted, using all available data for the 13C(α,n)16O, 13C(α, α)13C, and 16O(n,n)16O reactions. Of particular importance was the inclusion of the fixed ANC for the 1 / 2 + state at 6 . 356 MeV in 17O, which was measured recently using the sub-Coulomb α-transfer reaction, as well as the new 13C+ α elastic-scattering data measured in the low-energy region 1 . 6 - 3 . 8 MeV. Important constraining information on various resonances was found, and the uncertainty for the astrophysical 13C(α,n)16O reaction rate was dramatically reduced. Much work on the analysis was done by A. K. Nurmukhanbetova from National Laboratory Astana in Astana, Kazakhstan.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. States of {sup 15}C via the ({sup 18}O,{sup 16}O) reaction

    SciTech Connect

    Cappuzzello, F.; Carbone, D.; Cavallaro, M.; Cunsolo, A.; Orrigo, S. E. A.; Foti, A.; Rodrigues, M. R. D.

    2010-04-30

    A study of the {sup 15}C states was pursued in 2008 at the Catania INFN-LNS laboratory by the {sup 13}C({sup 18}O,{sup 16}O){sup 15}C reaction at 84 MeV incident energy. The {sup 16}O ejectiles were detected at forward angles by the MAGNEX magnetic spectrometer. The spectra show several known low lying states up to about 7 MeV excitation energy as well as two unknown resonant structures at about 11.4 and 13.5 MeV. The strong excitation of these latter together with the measured width of about 2 MeV FWHM could indicate the presence of collective modes of excitation connected to the transfer of a correlated neutron pair.

  19. Incomplete fusion reactions in 16O+159Tb system: Spin distribution measurements

    NASA Astrophysics Data System (ADS)

    Sharma, Vijay R.; Yadav, Abhishek; Singh, Devendra P.; Singh, Pushpendra P.; Gupta, Sunita; Sharma, Manoj K.; Bala, Indu; Kumar, R.; Muralithar, S.; Singh, R. P.; Singh, B. P.; Prasad, R.; Bhowmik, R. K.

    2015-01-01

    In order to explore the reaction modes on the basis of their entry state spin population, an experiment has been done by employing particle-γ coincidence technique carried out at the Inter University Accelerator Centre, New Delhi. The preliminary analysis conclusively demonstrates, spin distribution for some reaction products populated via complete and/or incomplete fusion of 16O with 159Tb system found to be distinctly different. Further, the existence of incomplete fusion at low bombarding energies indicates the possibility to populate high spin states.

  20. 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.

  1. The Production of (26)Al in the Early Solar System by the (16)O((16)O, X)(26)Al(Gs) and (14)N((16)O, X)(26)Al(Gs) Reactions

    NASA Astrophysics Data System (ADS)

    Yildiz, Kazim Orhan

    1998-12-01

    The astrophysically short half life (0.74 Myr) of 26Al isotope makes it one of the more important extinct nuclides whose abundances in the early solar system can be used as a probe of the environment in which the solar system formed. The abundance of 26Al in the present galaxy deduced from the gamma ray observations ( (Mah84) and (Die95)) is about an order of magnitude lower than its meteoritic abundances measured in the form of an enhancement in the abundance of 26Mg (daughter of 26Al) over the solar system level (Was85). The existence of 26Al in the meteorites is an indication that some sort of nucleosynthesis event occurred less than a few million years before the collapse of the proto-solar cloud, perhaps during that collapse. The most widely accepted explanation is that a nearby stellar explosion (such as a supernova) injected large amounts of 26Al and some other extinct nuclides into the proto-solar cloud, possibly triggering the collapse of the cloud in the process (e.g., (Cam77), (Cam92) and (Cam95)). Motivated by the COMPTEL observation (Blo94) of unexpectedly high fluxes of gamma rays in the energy range of 3-7 MeV from the direction of the Orion complex, Clayton and Jin ( (Cla94), (Cla95a) and (Cla95b)) proposed several cosmic-ray scenarios for the production of 26Al in the early solar system. One of their scenarios is that the meteoritic 26Al was produced by the irradiation of the proto-solar material by oxygen-rich cosmic rays (with energies up to 10 MeV/nucleon) through the 12C(16O,x)26Algs reaction. In order to test this proposal Bateman et al. (Bat96b) measured the yield of the 12C(16O,x)26Al reaction and determined that the yield of this reaction alone is not large enough to produce the meteoritic abundances of 26Al. Even though Clayton and Jin (Cla95a) assumed the contribution to the yield from the 16O(16O,x)26Algs would not be significant, the yield of this reaction was measured in the experimental work of this thesis. Due to higher solar system

  2. 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.

  3. A study of the {sup 16}O (e, e'p) reaction at deep missing energies

    SciTech Connect

    Nilanga Liyanage

    1999-02-01

    The {sup 16}O(e,e'p) reaction was studied in the first physics experiment performed at Jefferson lab Hall A. In the quasielastic region cross sections were measured for both quasi parallel and perpendicular kinematics at q = 1000 MeV and {omega} = 445 MeV. From the data acquired in quasi parallel kinematics longitudinal and transverse response functions R{sub L} and R{sub T} were separated for E{sub miss} < 60 MeV. The perpendicular kinematics data were used to extract R{sub LT}, R{sub T}, and R{sub L } + V{sub TT}/V{sub L}R{sub TT} response functions for the same E{sub miss} range and for P{sub miss} < 310 MeV c. The {sub 16}O( e, e'p) cross section was measured in the dip region at q = 1026 MeV and {omega} = 586 MeV for 10 MeV < E{sub miss} < 320 MeV. This thesis presents the results for the missing energy continuum ( E{sub miss}>25 MeV) from this experiment.

  4. An overview of the 19F(p,α0)16 O reaction with direct methods

    NASA Astrophysics Data System (ADS)

    Dell’Aquila, D.; Lombardo, I.

    2016-04-01

    The study of the 19F(p,α)16O reaction at low energy is important both for Nuclear Structure and Astrophysics. Despite of its importance, the S-factor of this reaction is poorly known, especially at astrophysical energies. We present an overview of the 19F(p,α0)16O reaction cross section, as obtained from recent direct measurements and from published works in the literature. We include in the systematic also data from an unpublished work, where several excitation functions and angular distributions for α0 and απ channels are reported.

  5. 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.

  6. Direct measurement of {sup 4}He({sup 12}C, {sup 16}O)gamma reaction at KUTL

    SciTech Connect

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

    2010-06-01

    A {sup 12}C+{sup 4}He->{sup 16}O+gamma is regarded as the very important reaction to know the evolution of heavy stars. The cross section is, however, still unknown in spite of more than 40 years experiment in the world because of an existence of a resonance state of {sup 16}O at sub-threshold region. A cross section measurement with the direct detection of the produced {sup 16}O from E{sub cm} = 2.4 downto 0.7 MeV have been planned at Kyushu University Tandem Laboratory(KUTL). Detection of the {sup 16}O is the most possible method at low energy, since a detection efficiency of the {sup 16}O is very high.The new windowless blow-in gas target was developed to achieve the pressure of 24 Torr. Many movable slit were installed in a recoil mass separator, so that the backgrounds generated by the {sup 12}C beam was eliminated effectively. The results of recent experiments at E{sub cm} = 2.4 and 1.5 MeV are reported.

  7. 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.

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

    SciTech Connect

    Katsuma, M.

    2008-09-15

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

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

    SciTech Connect

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

    2014-11-11

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

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

    SciTech Connect

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

    1993-01-01

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

  11. Revision of the 15N(p, γ)16O reaction rate and oxygen abundance in H-burning zones

    NASA Astrophysics Data System (ADS)

    Caciolli, A.; Mazzocchi, C.; Capogrosso, V.; Bemmerer, D.; Broggini, C.; Corvisiero, P.; Costantini, H.; Elekes, Z.; Formicola, A.; Fülöp, Zs.; Gervino, G.; Guglielmetti, A.; Gustavino, C.; Gyürky, Gy.; Imbriani, G.; Junker, M.; Lemut, A.; Marta, M.; Menegazzo, R.; Palmerini, S.; Prati, P.; Roca, V.; Rolfs, C.; Rossi Alvarez, C.; Somorjai, E.; Straniero, O.; Strieder, F.; Terrasi, F.; Trautvetter, H. P.; Vomiero, A.

    2011-09-01

    Context. The NO cycle takes place in the deepest layer of a H-burning core or shell, when the temperature exceeds T ≃ 30 × 106 K. The O depletion observed in some globular cluster giant stars, always associated with a Na enhancement, may be due to either a deep mixing during the red giant branch (RGB) phase of the star or to the pollution of the primordial gas by an early population of massive asymptotic giant branch (AGB) stars, whose chemical composition was modified by the hot bottom burning. In both cases, the NO cycle is responsible for the O depletion. Aims: The activation of this cycle depends on the rate of the 15N(p, γ)16O reaction. A precise evaluation of this reaction rate at temperatures as low as experienced in H-burning zones in stellar interiors is mandatory to understand the observed O abundances. Methods: We present a new measurement of the 15N(p, γ)16O reaction performed at LUNA covering for the first time the center of mass energy range 70-370 keV, which corresponds to stellar temperatures between 65 × 106 K and 780 × 106 K. This range includes the 15N(p, γ)16O Gamow-peak energy of explosive H-burning taking place in the external layer of a nova and the one of the hot bottom burning (HBB) nucleosynthesis occurring in massive AGB stars. Results: With the present data, we are also able to confirm the result of the previous R-matrix extrapolation. In particular, in the temperature range of astrophysical interest, the new rate is about a factor of 2 smaller than reported in the widely adopted compilation of reaction rates (NACRE or CF88) and the uncertainty is now reduced down to the 10% level.

  12. 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.

  13. 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.

  14. The Impact of the Uncertainties in the 12C(α,γ)16O Reaction Rate on the Asteroseismology of ZZ Ceti Stars: First Results

    NASA Astrophysics Data System (ADS)

    De Gerónimo, Francisco C.; Córsico, Alejandro H.; Althaus, Leandro G.; Romero, Alejandra D.

    2015-06-01

    We assess for the first time the impact that the uncertainties affecting the 12C(α,γ)16O reaction rate have on the asteroseismological inferences of ZZ Ceti stars. For our adopted test-case, the well studied DAV star G117-B15A, we found that the incomplete knowledge of the 12C(α,γ)16O nuclear reaction rate results in a moderate dispersion of the structural parameters of the asteroseismological model.

  15. Complete and incomplete fusion reactions in the {sup 16}O+{sup 169}Tm system: Excitation functions and recoil range distributions

    SciTech Connect

    Sharma, Manoj Kumar; Unnati,; Sharma, B.K.; Singh, B.P.; Prasad, R.; Bhardwaj, H.D.; Kumar, Rakesh; Golda, K.S.

    2004-10-01

    With the view to study complete and incomplete fusion in heavy ion induced reactions, experiments have been carried out for measuring excitation functions for several reactions in the system {sup 16}O+{sup 169}Tm at energies near the Coulomb barrier to well above it, using an activation technique. The measured excitation functions have been compared with those calculated theoretically using three different computer codes viz., ALICE-91, CASCADE and PACE2. The enhancement of experimentally measured cross sections for alpha emission channels over their theoretical prediction has been attributed to the fact that these residues are formed not only by complete fusion but also through incomplete fusion. In order to separate out the relative contributions of complete and incomplete fusion, the recoil range distributions of eight residues produced in the interaction of {sup 16}O with {sup 169}Tm at {approx_equal}87 MeV have been measured. The recoil range distributions indicate significant contributions from incomplete fusion at {approx_equal}87 MeV for some of the channels.

  16. Direct Total Cross Section Measurement of the 16O(α,γ)20Ne Reaction at Ec.m. = 2.26 MeV

    SciTech Connect

    Hager, Ulrike; Brown, James R.; Buchmann, Lothar R.; Carmona-Gallardo, Mariano; Erikson, Luke E.; Fallis, Jennifer S.; Greife, Uwe; Hutcheon, Dave; Ottewell, Dave; Ruiz, Chris; Sjue, Sky; Vockenhuber, Cristof

    2011-08-23

    In stellar helium burning, (16)O represents the endpoint of the helium-burning sequence due to the low rate of (16)O(alpha,gamma)(20)Ne. We present a new direct measurement of the total capture reaction rate of (16)O(alpha,gamma)(20)Ne at E(c.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.

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

    SciTech Connect

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

    2010-08-12

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

  18. 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.

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

    NASA Astrophysics Data System (ADS)

    Sadeghi, H.; Firoozabadi, M. M.

    2016-01-01

    On the basis of the four-alphamodel, the 12C(α, γ)16Oradiative 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 12C(α, γ)16Oradiative 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 4He + 12C (1 + 3) and the 8Be + 8Be (2 + 2) subamplitudes, respectively. Radiative capture 12C(α, γ)16Oreaction 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+ and 0+ ground state nuclei 16O 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 1 and E 2 contribution to the cross section and the astrophysical S factor for this process.

  20. 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.

  1. (16) O/(18) O Exchange of Aldehydes and Ketones caused by H2 (18) O in the Mechanistic Investigation of Organocatalyzed Michael, Mannich, and Aldol Reactions.

    PubMed

    Hayashi, Yujiro; Mukaiyama, Takasuke; Benohoud, Meryem; Gupta, Nishant R; Ono, Tsuyoshi; Toda, Shunsuke

    2016-04-18

    Organocatalyzed Michael, Mannich, and aldol reactions of aldehydes or ketones, as nucleophiles, have triggered several discussions regarding their reaction mechanism. H2 (18) O has been utilized to determine if the reaction proceeds through an enamine or enol mechanism by monitoring the ratio of (18) O incorporated into the final product. In this communication, we describe the risk of H2 (18) O as an evaluation tool for this mechanistic investigation. We have demonstrated that exchange of (16) O/(18) O occurs in the aldehyde or ketone starting material, caused by the presence of H2 (18) O and amine catalysts, before the Michael, Mannich, and aldol reactions proceed. Because the newly generated (18) O starting aldehydes or ketones and (16) O water affect the incorporation ratio of (18) O in the final product, the use of H2 (18) O would not be appropriate to distinguish the mechanism of these organocatalyzed reactions. PMID:26841358

  2. 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.

  3. Measurement of sub threshold resonance contributions to fusion reactions: the case of the 13C(α, n)16O astrophysical neutron source

    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.

    2015-01-01

    The 13C(α, n)16O reaction is the neutron source for the main component of the s-process. It is is active inside the helium-burning shell of asymptotic giant branch stars, at temperatures ≲ 108 K. In this temperature region, corresponding to an energy interval of 140 - 230 keV, the 13C(α, n)16O cross section is dominated by the -3 keV sub-threshold resonance due to the 6.356 MeV level in 17O. Direct measurements could not establish its contribution owing to the Coulomb barrier between interacting nuclei, strongly reducing the cross section at astrophysical energies. Similarly, indirect measurements and extrapolations yielded inconsistent results, calling for further investigations. The Trojan Horse Method was applied to the 13C(6Li, n16O)d quasi-free reaction to access the low as well as the negative energy region of the 13C(α, n)16O reaction. By using the generalized R-matrix approach, the asymptotic normalization coefficient (C˜17O(1/2+)α13C)2 of the 6.356 MeV level was deduced. For the first time, the Trojan Horse Method and the asymptotic normalization coefficient were used in synergy. Our indirect approach lead to (C˜17O(1/2+)α13C)2 = 7.7-1.5+1.6 fm-1, slightly larger than the values in the literature, determining a 13C(α, n)16O reaction rate slightly larger than the one in the literature at temperatures lower than 108 K, with enhanced accuracy.

  4. Monitoring the irradiation field of 12C and 16O SOBP beams using positron emitters produced through projectile fragmentation reactions

    NASA Astrophysics Data System (ADS)

    Inaniwa, Taku; Kohno, Toshiyuki; Tomitani, Takehiro; Sato, Shinji

    2008-02-01

    In order to effectively utilize the prominent properties of heavy ions in radiotherapy, it is important to evaluate both the position of the field irradiated with incident ions and the absorbed dose distribution in a patient's body. One of the methods for this purpose is the utilization of the positron emitters produced through the projectile fragmentation reactions of stable heavy ions with target nuclei. In heavy-ion therapy, spread-out Bragg peak (SOBP) beams are used to achieve uniform biological dose distributions in the whole tumor volume. Therefore, in this study, we designed SOBP beams of 30 and 50 mm water-equivalent length (mmWEL) in width for 12C and 16O, and carried out irradiation experiments using them. Water, polyethylene and polymethyl methacrylate were selected as targets to simulate a human body. Pairs of annihilation gamma rays were detected by means of a limited-angle positron camera for 500 s, and annihilation gamma-ray distributions were obtained. The maximum likelihood estimation (MLE) method was applied to the detected distributions for evaluating the positions of the distal and proximal edges of the SOBP in a target. The differences between the positions evaluated with the MLE method and those derived from the measured dose distributions were less than 1.7 mm and 2.5 mm for the distal and the proximal edge, respectively, in all irradiation conditions. When the positions of both edges are determined with the MLE method, the most probable shape of the dose distribution in a target can be estimated simultaneously. The close agreement between the estimated and the measured distributions implied that the shape of the dose distribution in an irradiated target could be evaluated from the detected annihilation gamma-ray distribution.

  5. Preliminary Study of Two-Neutron States via the ({sup 18}O,{sup 16}O) Reaction at 84 MeV

    SciTech Connect

    Cavallaro, M.; Tudisco, S.; Cappuzzello, F.; Carbone, D.; Cunsolo, A.; Bondi, M.; Santagati, G.; Taranto, G.; Foti, A.; Chen, R.; Linares, R.; Azaiez, F.; Franchoo, S.; Niikura, M.; Scarpaci, J. A.

    2011-10-28

    A study of light neutron-rich nuclei has been performed at the INFN-LNS laboratory in Catania (Italy) by the ({sup 18}O, {sup 16}O) reaction at 84 MeV incident energy on {sup 9}Be, {sup 11}B and {sup 13}C targets. The {sup 16}O ejectiles have been momentum analyzed and detected at forward angles by the MAGNEX magnetic spectrometer. The energy spectra of {sup 15}C show several known low lying states up to about 7 MeV excitation energy and unknown resonant structures at higher excitation energy. The strong excitation of these latter together with the measured width of about 2 MeV FWHM could indicate the presence of collective modes of excitation connected to the transfer of a correlated neutron pair. Also considerations regarding the reaction mechanism and the nuclei involved in the transfer seem to confirm such a conclusion. Similar features characterize the energy spectra of the {sup 11}Be and {sup 13}B nuclei. The achieved mass resolution (about 1/160) guarantying the identification of the reaction products corresponding to different reaction channels has allowed to study the relative yields for the different reaction channels. The measured yields show an enhancement of the two-neutron transfer channel compared to the one-neutron transfer. This result seems to indicate that the ({sup 18}O, {sup 16}O) reaction proceeds mainly by the direct transfer of the neutron pair and that the second order processes are negligible.

  6. 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.

  7. 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.

  8. 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.

  9. /sup 12/C(/sup 6/Li,d)/sup 16/O. -->. cap alpha. +/sup 12/C reaction mechanism by means of angular correlation measurements

    SciTech Connect

    Cunsolo, A.; Foti, A.; Imme, G.; Pappalardo, G.; Raciti, G.; Saunier, N.

    1980-06-01

    The particle-particle angular correlation method is applied to the reaction /sup 12/C(/sup 6/Li,d)/sup 16/O ..-->.. ..cap alpha..+/sup 12/C. Deuterons were detected at theta/sup lab//sub d/=10/sup 0/. Information on the reaction mechanism is obtained by analyzing the shape and the angular shift of the experimental data. A dominant direct transfer mechanism is found for the primary reaction. The ratios GAMMA..cap alpha../sub 0//GAMMA and the ..cap alpha..-reduced widths ..gamma cap alpha../sub 0/ are deduced.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Measurement of fusion cross sections for 16O+16O

    NASA Astrophysics Data System (ADS)

    Duarte, J. G.; Gasques, L. R.; Oliveira, J. R. B.; Zagatto, V. A. B.; Chamon, L. C.; Medina, N. H.; Added, N.; Seale, W. A.; Alcántara-Núñez, J. A.; Rossi, E. S., Jr.; Amador-Valenzuela, P.; Lépine-Szily, A.; Freitas, A. S.; Scarduelli, V.; Aguiar, V. A. P.; Shorto, J. M. B.

    2015-06-01

    In earlier works, the fusion cross section for the 16O+16O reaction has been measured using different techniques. In the present work, we have obtained an experimental excitation function for 16O+16O using γ-ray spectroscopy. The measurements were performed at center-of-mass energies between 8.28 and 12.25 MeV. The theoretical predictions obtained with a coupled-channel model are consistent with the experimental data. From our analyses, the extrapolated S-factor value at 6.6 MeV, corresponding to the Gamow peak energy for core oxygen burning conditions, is about 3.6 × 1025 MeV barn.

  16. Observation of breakup transfer process for the bound states of {sup 16}O populated from {sup 12}C({sup 6}Li,d) reaction at 20 MeV

    SciTech Connect

    Adhikari, S.; Basu, C.; Thompson, I. J.; Sugathan, P.; Jhinghan, A.; Golda, K. S.; Babu, A.; Singh, D.; Ray, S.; Mitra, A. K.

    2012-10-20

    The deuteron angular distribution for the {sup 12}C({sup 6}Li,d){sup 16}O* has been measured at 20 MeV populating bound and unbound states of {sup 16}O. Analysis shows a dominance of breakup induced alpha transfer in comparison to a direct alpha transfer process for the bound states. The effect increases as the excitation energy of {sup 16}O decreases, maximizing at the ground state.

  17. Reaction mechanism in the {sup 16}O+{sup 27}Al system: Measurements and analysis of excitation functions and angular distributions

    SciTech Connect

    Sharma, Manoj Kumar; Unnati,; Singh, Devendra P.; Singh, Pushpendra P.; Singh, B. P.; Prasad, R.; Bhardwaj, H. D.

    2007-06-15

    To study the dynamics of heavy ion fusion reactions in the lower mass region, experiments were carried out to measure the cross sections of radioactive residues produced in the interaction of the {sup 16}O ion with {sup 27}Al target nucleus at 19 different energies in very close intervals covering the energy range from {approx_equal}58 to 94 MeV, using the well-known recoil catcher off-line {gamma}-ray spectroscopy technique. The simulation of experimental data was performed using statistical-model-based computer codes, viz., CASCADE, PACE2, and ALICE-91. The analysis of measured excitation functions indicates that these residues are likely to be produced by complete fusion, incomplete fusion, and direct reaction processes. Furthermore, to confirm the contribution of different reaction channels, a complementary experiment was performed that measured the angular distributions of the residues produced in the {sup 16}O+{sup 27}Al system at 85 MeV beam energy. The analysis of the results of both experiments indicates that at these energies, the direct reactions compete with complete fusion and incomplete fusion reaction processes.

  18. New Determination of the 13C(α, n)16O Reaction Rate and its Influence on the s-process Nucleosynthesis in AGB Stars

    NASA Astrophysics Data System (ADS)

    Guo, B.; Li, Z. H.; Lugaro, M.; Buntain, J.; Pang, D. Y.; Li, Y. J.; Su, J.; Yan, S. Q.; Bai, X. X.; Chen, Y. S.; Fan, Q. W.; Jin, S. J.; Karakas, A. I.; Li, E. T.; Li, Z. C.; Lian, G.; Liu, J. C.; Liu, X.; Shi, J. R.; Shu, N. C.; Wang, B. X.; Wang, Y. B.; Zeng, S.; Liu, W. P.

    2012-09-01

    We present a new measurement of the α-spectroscopic factor (S α) and the asymptotic normalization coefficient for the 6.356 MeV 1/2+ subthreshold state of 17O through the 13C(11B, 7Li)17O transfer reaction and we determine the α-width of this state. This is believed to have a strong effect on the rate of the 13C(α, n)16O 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 13C(α, n)16O reaction. At a temperature of 100 MK, our rate is roughly two times larger than that by Caughlan & 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 13C(α, n)16O reaction when the 13C burns completely in radiative conditions. When the 13C burns in convective conditions, as in stars of initial mass lower than ~2 M ⊙ 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.

  19. Analysis of Neutron and Singly Charged Particle Multiplicities Induced by Collision of 4.5A GeV/c 16O with Emulsion Nuclei

    SciTech Connect

    El-Nagdy, M.S.; Abdel-Halim, S.M.; Nabil Yasin, M.

    2005-03-17

    The analysis of neutron n and singly charged particle Q=1 participated from 16O at 4.5A GeV/c interactions with emulsion nuclei are presented. The average multiplicities of shower particle for n and Q=1 stay more or less constant when compared with analogous data on P-A at similar momentum. The multiplicity distributions as well as the average values of the various secondary particles are studied, discussed and compared with the calculations according cascade evaporation model. The results lead to assume that the n and Q=1 from 16O tend to collide peripherally with target emulsion or in other words to make gentle reactions.

  20. 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.

  1. Extracting the cross section angular distributions for 15C high-energy resonance excited via the (18O,16O) two-neutron transfer reaction

    NASA Astrophysics Data System (ADS)

    Carbone, D.; Agodi, C.; Cappuzzello, F.; Cavallaro, M.; Foti, A.; Linares, R.

    2016-05-01

    The 13C(18O,16O)15C reaction has been studied at 84 MeV incident energy. The ejectiles have been momentum analized by the MAGNEX spectrometer and 15C excitation energy spectra have been obtained up to about 20 MeV. In the region above the two-neutron separation energy, a bump has been observed at 13.7 MeV. The extracted cross section angular distribution for this structure, obtained by using different models for background, displays a clear oscillating pattern, typical of resonant state of the residual nucleus.

  2. 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.

  3. 12C(16O, α)24Mg* reaction in the energy region Ec.m.=26.6 to 42.9 MeV

    NASA Astrophysics Data System (ADS)

    Bechara, M. J.; Lazzarini, A. J.; Ledoux, R. J.; Cosman, E. R.

    1983-04-01

    The 12C+16O resonance structure in the 28Si nucleus is examined by means of the 12C(16O, α)24Mg reaction excitation functions in the energy range Ec.m.=26.6 to 42.9 MeV in 430 keV steps at θlab=7.5°. We could identify 64 discrete states in 24Mg up to 31.7 MeV of excitation energy. The excitation functions show abundant structure over the entire energy range. The summed excitation functions, which tend to average out statistical fluctuations, show pronounced intermediate structure enhancement in the cross section at Ec.m.~=29.5, 32.2, and 35 MeV and indicate the presence of a smaller peak at 37.3 MeV. The widths of these structures are about 1 MeV, which is intermediate between the value expected from ion-ion potential resonances and statistical fluctuations. The nonstatistical character of these structures is reinforced by some statistical tests and by the correlations in energy and width found in several exit channels. Our data also suggest a possible structural relationship between the 28Si resonances and certain 24Mg final states. NUCLEAR REACTIONS 12C(16O, α)24Mg* measured σ(E) to states up to 31.7 MeV of excitation energy for Ec.m.=26.6 to 42.9 MeV in 430 keV steps, θlab=7.5°. Nonstatistical structure observed.

  4. 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.

  5. DEPENDENCE OF s-PROCESS NUCLEOSYNTHESIS IN MASSIVE STARS ON TRIPLE-ALPHA AND {sup 12}C({alpha}, {gamma}){sup 16}O REACTION RATE UNCERTAINTIES

    SciTech Connect

    Tur, Clarisse; Austin, Sam M.; Heger, Alexander E-mail: austin@nscl.msu.edu

    2009-09-10

    We have studied the sensitivity of s-process nucleosynthesis in massive stars to {+-}2{sigma} variations in the rates of the triple-{alpha} and {sup 12}C({alpha}, {gamma}){sup 16}O reactions. We simulated the evolution of massive stars from H burning through Fe-core collapse, followed by a supernova explosion. We found that the production factors of s-process nuclides between {sup 58}Fe and {sup 96}Zr change strongly with changes in the He burning reaction rates; using the Lodders solar abundances rather than those of Anders and Grevesse reduces s-process nucleosynthesis; later burning phases beyond core He burning and shell C burning have a significant effect on post-explosive production factors. We also discuss the implications of the uncertainties in the helium burning rates for evidence of a new primary neutron capture process (LEPP) in massive stars.

  6. Dependence of s-Process Nucleosynthesis in Massive Stars on Triple-Alpha and 12C(α, γ)16O Reaction Rate Uncertainties

    NASA Astrophysics Data System (ADS)

    Tur, Clarisse; Heger, Alexander; Austin, Sam M.

    2009-09-01

    We have studied the sensitivity of s-process nucleosynthesis in massive stars to ±2σ variations in the rates of the triple-α and 12C(α, γ)16O reactions. We simulated the evolution of massive stars from H burning through Fe-core collapse, followed by a supernova explosion. We found that the production factors of s-process nuclides between 58Fe and 96Zr change strongly with changes in the He burning reaction rates; using the Lodders solar abundances rather than those of Anders and Grevesse reduces s-process nucleosynthesis; later burning phases beyond core He burning and shell C burning have a significant effect on post-explosive production factors. We also discuss the implications of the uncertainties in the helium burning rates for evidence of a new primary neutron capture process (LEPP) in massive stars.

  7. Monte Carlo Simulation of Neutron Background Sources in the Measurement of the ^12C(α,γ)^16O Reaction Rate

    NASA Astrophysics Data System (ADS)

    Gullikson, Kevin; Ugalde, Claudio

    2009-10-01

    The ^12C(α, γ)^16O reaction rate strongly affects the relative abundances of chemical elements, as well as when core collapse supernovae occur. In a proposed experiment, a water-filled bubble chamber will be used to measure the reverse reaction rate. A potential background source is photoneutrons from the γ-ray beam collimator entering the bubble chamber and generating a false signal. To minimize this effect, a Monte Carlo simulation has been performed to compare the number of photoneutrons created in lead, copper, and aluminum collimators. The simulation also compared the effectiveness of concrete, polyethylene, and water neutron shields. It was found that 30 cm of copper would be an effective collimator, and 30-40 cm of polyethylene a satisfactory neutron shield.

  8. 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.

  9. 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.

  10. 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.

  11. Center-of-mass effects on the quasihole spectroscopic factors in the {sup 16}O(e,e{sup {prime}}p) reaction

    SciTech Connect

    Van Neck, D.; Waroquier, M.; Dieperink, A.E.; Pieper, S.C.; Pandharipande, V.R.

    1998-05-01

    The spectroscopic factors for the low-lying quasihole states observed in the {sup 16}O(e,e{sup {prime}}p){sup 15}N reaction are reinvestigated with a variational Monte Carlo calculation for the structure of the initial and final nucleus. A computational error in a previous report is rectified. It is shown that a proper treatment of center-of-mass motion does not lead to a reduction of the spectroscopic factor for p-shell quasihole states, but rather to a 7{percent} enhancement. This is in agreement with analytical results obtained in the harmonic oscillator model. The center-of-mass effect worsens the discrepancy between present theoretical models and the experimentally observed single-particle strength. We discuss the present status of this problem, including some other mechanisms that may be relevant in this respect. {copyright} {ital 1998} {ital The American Physical Society}

  12. Study of the reactions occurring in the fusion of {sup 12}C and {sup 16}O with heavy nuclei at incident energies below 10 MeV/nucleon

    SciTech Connect

    Cavinato, M.; Fabrici, E.; Gadioli, E.; Gadioli Erba, E.; Vergani, P.; Crippa, M.; Colombo, G.; Redaelli, I.; Ripamonti, M.

    1995-11-01

    The excitation functions for production of many residues in the fusion of {sup 12}C with {sup 181}Ta and {sup 197}Au and of {sup 16}O with {sup 165}Ho and {sup 181}Ta have been measured at incident energies varying from the Coulomb barrier up to about 10 MeV/nucleon. The cross sections for fusion of these ions without fission have been deduced and they show that such a process may only occur for projectile angular momenta smaller than a critical value. The excitation functions for individual reactions provide evidence for the emission of preequilibrium nucleons during the thermalization of the composite nucleus and may be satisfactorily reproduced by a calculation based on the Boltzmann master equation theory.

  13. 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.

  14. Helium-induced reactions in astrophysics

    SciTech Connect

    Hale, G.M.

    1997-11-01

    Helium-induced reactions play a crucial role in stellar nucleosynthesis. Carbon and oxygen are produced mainly during the helium-burning phase by the chain of reactions {sup 8}Be({alpha}, {gamma} + e{sup +}e{sup {minus}}){sup 12}C({alpha}, {gamma}){sup 16}O. The first step, often called triple-{alpha} capture, was proposed by Hoyle to bypass the mass stability gap at {sup 8}Be. The second step gives rise to the largest uncertainty in most of the calculated stellar abundances. Later {alpha}-captures on {sup 13}C are believed to be a major source of s-process neutrons. The status of each of these important reactions is reviewed here.

  15. Astrophysical Reaction Rate for the Neutron-Generator Reaction {sup 13}C({alpha},n){sup 16}O in Asymptotic Giant Branch Stars

    SciTech Connect

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

    2006-11-10

    The reaction {sup 13}C({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{sup +} 6.356 MeV subthreshold resonance in {sup 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 ({sup 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.

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

    NASA Astrophysics Data System (ADS)

    Sharma, Arun

    2016-05-01

    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 16O+Br80,84,92 and 16O+Ag108,113,122. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Angular correlations of projectilelike and fission fragments in the reaction [sup 16]O+[sup 238]U at 110 MeV

    SciTech Connect

    Pagano, A.; Aiello, S.; De Filippo, E.; Lanzano, G.; Lo Nigro, S.; Milone, C. ); Mermaz, M.C. )

    1994-08-01

    In-plane and out-of-plane angular correlations of fission fragments detected in coincidence with projectilelike residues produced in the nuclear collisions [sup 16]O+[sup 238]U at 110 MeV have been investigated. The data present the essential features of a targetlike sequential fission process. A quantitative description of the experimental angular anisotropies requires the storage in the fissioning nucleus of a mean angular momentum in agreement with a dominant mass transfer mechanism.

  1. Laser induced nuclear reactions

    SciTech Connect

    Ledingham, Ken; McCanny, Tom; Graham, Paul; Fang Xiao; Singhal, Ravi; Magill, Joe; Creswell, Alan; Sanderson, David; Allott, Ric; Neely, David; Norreys, Peter; Santala, Marko; Zepf, Matthew; Watts, Ian; Clark, Eugene; Krushelnick, Karl; Tatarakis, Michael; Dangor, Bucker; Machecek, Antonin; Wark, Justin

    1998-12-16

    Dramatic improvements in laser technology since 1984 have revolutionised high power laser technology. Application of chirped-pulse amplification techniques has resulted in laser intensities in excess of 10{sup 19} W/cm{sup 2}. In the mid to late eighties, C. K. Rhodes and K. Boyer discussed the possibility of shining laser light of this intensity onto solid surfaces and to cause nuclear transitions. In particular, irradiation of a uranium target could induce electro- and photofission in the focal region of the laser. In this paper it is shown that {mu}Ci of {sup 62}Cu can be generated via the ({gamma},n) reaction by a laser with an intensity of about 10{sup 19} Wcm{sup -2}.

  2. Examination of the surrogate ratio method for the determination of the 93Zr(n ,γ )94Zr cross section with Zr,9290(18O,16O)Zr,9492 reactions

    NASA Astrophysics Data System (ADS)

    Yan, S. Q.; Li, Z. H.; Wang, Y. B.; Nishio, K.; Makii, H.; Su, J.; Li, Y. J.; Nishinaka, I.; Hirose, K.; Han, Y. L.; Orlandi, R.; Shen, Y. P.; Guo, B.; Zeng, S.; Lian, G.; Chen, Y. S.; Bai, X. X.; Qiao, L. H.; Liu, W. P.

    2016-07-01

    The relative γ -decay probability ratios of the neutron resonance states in 94Zr and 92Zr populated via two-neutron transfer reactions, 92Zr(18O,16O)94Zr and 90Zr(18O,16O)92Zr , have been measured to test the validity of the surrogate ratio method (SRM) in determining the (n , γ ) reaction cross section. The cross sections of the 93Zr(n ,γ )94Zr reaction are derived from the experimentally obtained ratios and the cross sections of the 91Zr(n ,γ )92Zr reaction in the equivalent neutron energy range of En=0 -8 MeV . The deduced cross sections of 93Zr(n ,γ )94Zr reaction agree with the directly measured ones in the low-energy region, and with the evaluated ENDF/B-VII.1 data at higher energies of En>3 MeV . The agreement supports the concept of the SRM method to indirectly determine the (n ,γ ) reaction cross sections.

  3. 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.

  4. The {beta}-delayed {alpha}-spectrum of {sup 16}N and the astrophysical aspects of the {sup 12}C({alpha},{gamma}){sup 16}O reaction

    SciTech Connect

    Azuma, R.E.; Buchmann, L.; Barker, F.C.

    1995-08-01

    Radiative alpha-capture by {sup 12}C is a key process occurring during the helium-burning phase in red giant stars, and its rate remains one of the most significant uncertainties in the nucleosynthetic calculations for massive stars. This is largely due to the lack of precise experimental information concerning the values of the reduced {alpha}-particle widths of the J{sup {pi}} = 1{sup {minus}} and 2{sup +} subthreshold states in {sup 16}O to which the higher-energy radiative capture data are only weakly sensitive. Of these two states, the reduced {alpha}-width of the E{sub x} = 7.12 MeV J{sup {pi}} = 1{sup {minus}} level has been predicted to have a considerable effect on the structure of the hitherto unmeasured low-energy region of the {beta}-delayed {alpha}-particle spectrum of {sup 16}N. Experiments using the TRIUMF isotope separator TISOL have been performed to measure this {alpha}-spectrum down to an energy of E{sub {alpha}} = 600 keV, utilizing a coincidence technique which also accounts completely for the detector response function. The {alpha}-spectrum, containing 10{sup 6} counts, has been incorporated into both R- and K-matrix analyses along with the previously measured {sup 12}C({alpha},{gamma}){sup 16}O cross section and the {sup 12}C + {alpha} elastic phase shifts to yield a much improved value for S{sub E1}(300) keV. In light of this new determination of S{sub E1}(300), the available radiative capture data and elastic scattering phase shifts are re-analyzed, along with {beta}-delayed {alpha}-spectrum of {sup 16}N in an attempt also to place improved limits on the S{sub E1}(300) contribution to the {sup 12}C({alpha},{gamma}){sup 16}O cross section.

  5. 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.

  6. 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.

  7. The {sup 17}F(p,{gamma}){sup 18}Ne3{sup +} resonance state studied with the {sup 16}O({sup 3}He,n){sup 18}Ne reaction

    SciTech Connect

    Parpottas, Y.; Grimes, S.M.; Brune, C.R.; Massey, T.N.; O'Donnell, J.E.; Oldendick, J.E.; Salas, A.; Wheeler, R.T.; Al-Quraishi, S.

    2005-08-01

    The astrophysically important 3{sup +} resonance of the {sup 17}F(p,{gamma}){sup 18}Ne reaction has been studied with the {sup 16}O({sup 3}He,n){sup 18}Ne reaction. High-resolution measurements were carried out for three different kinematic configurations. We find an excitation energy of 4527(4) keV and a proton width of 17(4) keV for the 3{sup +} state. Measured differential cross sections were compared with Hauser-Feshbach predictions to assign the spin of the 4527-keV state and confirm the spin assignments of the two known levels in this region. Our results differ from the earlier {sup 16}O({sup 3}He,n){sup 18}Ne findings of Garcia et al. [Phys. Rev. C 43, 2012 (1991)], but they agree well with the {sup 17}F(p,p){sup 17}F measurements of Bardayan et al. [Phys. Rev. C 62, 055804 (2002)].

  8. Kinetic isotope effect of the (16)O + (36)O2 and (18)O + (32)O2 isotope exchange reactions: Dominant role of reactive resonances revealed by an accurate time-dependent quantum wavepacket study.

    PubMed

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

    2015-05-01

    The O + O2 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 (18)O + (32)O2 and (16)O + (36)O2 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. PMID:25956105

  9. Kinetic isotope effect of the 16O + 36O2 and 18O + 32O2 isotope exchange reactions: Dominant role of reactive resonances revealed by an accurate time-dependent quantum wavepacket study

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

    The O + O2 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 18O + 32O2 and 16O + 36O2 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.

  10. Incomplete fusion in 16O+159Tb

    NASA Astrophysics Data System (ADS)

    Sharma, Vijay R.; Singh, Pushpendra P.; Shuaib, Mohd.; Yadav, Abhishek; Bala, Indu; Sharma, Manoj K.; Gupta, S.; Singh, D. P.; Kumar, R.; Muralithar, S.; Singh, R. P.; Singh, B. P.; Prasad, R.; Bhowmik, R. K.

    2016-02-01

    In heavy-ion induced reactions, incomplete fusion (ICF) has been found to be a process of greater importance and of distinct nature even at slightly above the barrier energies where complete fusion (CF) is supposed to be dominant. However, the studies are limited to a few projectile target combinations only. To confirm the distinctly different decay patterns observed in case of CF and ICF residues, and to understand the role of high ℓ-values in the onset of ICF, a particle-γ-coincidence technique has been employed to measure spin-distributions and feeding intensity profiles of CF and ICF residues populated via xn / pxn / αxn-channels in 16O+159Tb interactions at Elab ≈ 83.5 ± 1.5, 88.5 ± 1.5, 93.5 ± 1.5 and 97.6 ± 1.4 MeV. The Gamma Detector Array and the Charged Particles Detector Array have been used to detect prompt γ-rays in coincidence with charged particles (p and α). CF-α and ICF-α channels have been identified from backward (B)- and forward (F)-α-gated-γ-spectra, respectively. Reaction dependent decay patterns (thus, the feeding intensity profiles) have been observed in different α emitting channels. The CF channels are found to be widely populated and strongly fed over a broad spin range. In case of ICF-α channels, narrow range feeding was observed only for high-spin states or the low spin states were not populated. The mean ℓ-values involved in the production of ICF- αxn-channels are found to be higher than those involved in the production of CF- αxn-channels associated with fusion-evaporation reactions.

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  12. 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.

  13. 16O(n,α) cross section investigation using LENZ instrument at LANSCE

    NASA Astrophysics Data System (ADS)

    Lee, H. Y.; Mosby, S.; Haight, R. C.; White, M. C.

    2016-06-01

    Importance of studying the 16O(n,α) reaction is motivated by multiple nuclear applications. The Los Alamos Neutron Science Center (LANSCE) produces a white neutron spectrum ranging from thermal to several hundreds of MeV energies. We have recently developed the LENZ (Low Energy NZ-neutron induced charged particle detection) capability to measure high-precision (n,α) cross sections. In order to provide more reliable data, we have enhanced solid angle coverage, and improved signal-to-noise ratios and time-of-flight resolution by implementing digitizer waveform analysis. The LENZ was commissioned by studying the 59Co(n,α) reaction with neutron beams in early 2015. For the 16O(n,α) reaction, we investigate solid oxygen targets and make a relative measurement to a better known cross section, such as the 6Li(n,α) reaction in order to further reduce systematic uncertainty. We will discuss the progress of the 16O(n,α) study at LANSCE and the outlook for improving Hauser-Feshbah prediction on (n,p) reaction cross sections.

  14. 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.

  15. Clindamycin-induced hypersensitivity reaction.

    PubMed

    Bulloch, Marilyn N; Baccas, Jonathan T; Arnold, Scott

    2016-06-01

    Drug-induced anaphylaxis is an unpredictable adverse reaction. Although it may occur with any medication, antibiotics induce more cases of anaphylaxis than any other medication class with most cases being induced by β-lactam antibiotics. Clindamycin is an antibiotic with good gram-positive and anaerobe coverage which is often used in patients with β-lactam allergies. We report the case of a 46-year-old female who experienced anaphylaxis after a dose of intravenous (IV) clindamycin. Following treatment with methylprednisolone, epinephrine, diphenhydramine, and albuterol, the patient stabilized. The patient's score on the Naranjo's algorithm was 8 (probable); a score of 9 (definite) limited only by absence of drug re-challenge. To our knowledge, this is the first report of a clindamycin-induced anaphylaxis where the patient was not exposed to any other agent that may have triggered the response, the first case in the United States, and only the third documented case in the literature. Clinicians should be aware of the potential for drug-induced anaphylaxis in all medications. PMID:26216470

  16. Complete and incomplete momentum transfer components in the [sup nat]Si([sup 16]O,[ital X]) reaction at 96. 4, 112. 4, and 127. 8 MeV

    SciTech Connect

    Zingarelli, R.A.; Dennis, L.C.; Tiede, M.A.; Kline, R.C.; Kemper, K.W.; Mitchell, S.V. )

    1993-08-01

    Angular distributions and inclusive energy spectra of isotopes with masses 23--41 were measured for the reaction [sup nat]Si([sup 16]O,[ital X]) at bombarding energies of 96.4, 112.4, and 127.8 MeV. Complete and incomplete projectile momentum transfer components of the resulting velocity distributions were separated by kinematic transforms which rely on an angular distribution function fitted to the data using center-of-mass frame symmetry conditions. Characteristics of the extracted complete momentum transfer component spectra, mass distributions, and laboratory frame angular distributions are consistent with fusion-evaporation models. Comparison with the Glas-Mosel parametrization and predictions for the angular momentum barrier to fusion indicate that at 112.4 and 127.8 MeV, competing entrance channel processes, rather than compound nucleus formation limits, restrict the fusion cross section. Spectra and cross sections of the incomplete momentum transfer component are consistent with sequential two-body breakup/fusion calculations.

  17. Complete and incomplete momentum transfer components in the natSi(16O,X) reaction at 96.4, 112.4, and 127.8 MeV

    NASA Astrophysics Data System (ADS)

    Zingarelli, R. A.; Dennis, L. C.; Tiede, M. A.; Kline, R. C.; Kemper, K. W.; Mitchell, S. V.

    1993-08-01

    Angular distributions and inclusive energy spectra of isotopes with masses 23-41 were measured for the reaction natSi(16O,X) at bombarding energies of 96.4, 112.4, and 127.8 MeV. Complete and incomplete projectile momentum transfer components of the resulting velocity distributions were separated by kinematic transforms which rely on an angular distribution function fitted to the data using center-of-mass frame symmetry conditions. Characteristics of the extracted complete momentum transfer component spectra, mass distributions, and laboratory frame angular distributions are consistent with fusion-evaporation models. Comparison with the Glas-Mosel parametrization and predictions for the angular momentum barrier to fusion indicate that at 112.4 and 127.8 MeV, competing entrance channel processes, rather than compound nucleus formation limits, restrict the fusion cross section. Spectra and cross sections of the incomplete momentum transfer component are consistent with sequential two-body breakup/fusion calculations.

  18. (Reaction mechanism studies of heavy ion induced nuclear reactions)

    SciTech Connect

    Mignerey, A.C.

    1991-01-01

    This report discusses the following research projects; decay of excited nuclei formed in La-induced reactions at E/A = 45 MeV; mass and charge distributions in Cl-induced heavy ion reactions; and mass and charge distributions in {sup 56}Fe + {sup 165}Ho at E/A = 12 MeV.

  19. Absolute decay width measurements in 16O

    NASA Astrophysics Data System (ADS)

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

    2012-09-01

    The reaction 126C(63Li, d)168O* at a 6Li bombarding energy of 42 MeV has been used to populate excited states in 16O. The deuteron ejectiles were measured using the high-resolution Munich Q3D spectrograph. A large-acceptance silicon-strip detector array was used to register the recoil and break-up products. This complete kinematic set-up has enabled absolute α-decay widths to be measured with high-resolution in the 13.9 to 15.9 MeV excitation energy regime in 16O; many for the first time. This energy region spans the 14.4 MeV four-α breakup threshold. Monte-Carlo simulations of the detector geometry and break-up processes yield detection efficiencies for the two dominant decay modes of 40% and 37% for the α+12C(g.s.) and a+12C(2+1) break-up channels respectively.

  20. Dynamics of the quasielastic {sup 16}O(e,e{sup '}p) reaction at Q{sup 2}{approx_equal}0.8 (GeV/c){sup 2}

    SciTech Connect

    Fissum, K.G.; Liang, M.; Cardman, L.S.; Chen, J.-P.; Jager, C.W. de; Domingo, J.; Gomez, J.; LeRose, J.J.; Michaels, R.; Nanda, S.; Saha, A.; Wojtsekhowski, B.; Anderson, B.D.; Khayat, M.; Manley, D.M.; Petratos, G.G.; Prout, D.L.; Watson, J. W.; Aniol, K.A.; Auerbach, L.

    2004-09-01

    The physics program in Hall A at Jefferson Lab commenced in the summer of 1997 with a detailed investigation of the {sup 16}O(e,e{sup '}p) reaction in quasielastic, constant (q,{omega}) kinematics at Q{sup 2}{approx_equal}0.8 (GeV/c){sup 2}, q{approx_equal}1 GeV/c, and {omega}{approx_equal}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 0reaction is increasingly hidden by more complicated processes, and for 280

  1. Study of Quasielastic 1p-shell proton Knockout in the {sup 16}O (e,e'p) reaction at Q{sup 2}=0.8 (GeV/c){sup 2}

    SciTech Connect

    Juncai Gao

    1999-06-01

    Coincidence cross sections and the structure functions R{sub L+TT}, R{sub T} and R{sub LT} have been obtained for the quasielastic {sup 16}O( e, e'p) reaction with the proton knocked out from the 1p{sub 1/2} and 1p{sub 3/2} states in perpendicular kinematics. The nominal energy transfer {omega} was 439 MeV the nominal Q{sup 2} was 0.8 ( GeV/ c){sup 2} and the kinetic energy of knocked- out proton was 427 MeV. The data was taken in Hall A Je erson Laboratory using two high resolution spectrometers to detect electrons and protons respectively. Nominal beam energies 845 MeV , 1645 MeV and 2445 MeV were employed. For each beam energy, the momentum and angle of electron arm were fixed, while the angle between the proton momentum and the momentum transfer {vector q} was varied to map out the missing momentum. R{sub LT} was separated out to ~350 MeV /c in missing momentum. R{sub L+TT} and R{sub T} were separated out to ~280 MeV/ c in missing momentum. R{sub L} and R{sub T} were separated at a missing momentum of 52.5 MeV/ c for the data taken with hadron arm along {vector q}. The measured cross sections and response functions agree with both relativistic and non relativistic DWIA calculations employing spectroscopic factors between 60-75% for 1 p{sub 1/2} and 1 p{sub 3/2} states. The left- right asymmetry does not support the non -relativistic DWIA calculation using the Weyl gauge. Also the left- right asymmetry measurement favors the relativistic calculation. This thesis describes the details of the experimental setup , the calibration of the spectrometers, the techniques used in the data analysis to derive the fi nal cross sec tions as well as the response functions and the comparison of the results with the theoretical calculations.

  2. Effective radii of deuteron-induced reactions

    SciTech Connect

    Hashimoto, Shintaro; Chiba, Satoshi; Yahiro, Masanobu; Ogata, Kazuyuki; Minomo, Kosho

    2011-05-15

    The continuum-discretized coupled-channels method (CDCC) for exclusive reactions and the eikonal reaction theory (ERT) as an extension of CDCC to inclusive reactions are applied to deuteron-induced reactions. The CDCC result reproduces experimental data on the reaction cross section for d+{sup 58}Ni scattering at 200 MeV/nucleon, and ERT provides data on the neutron-stripping cross section for inclusive {sup 7}Li(d,n) reaction at 40 MeV. For deuteron-induced reactions at 200 MeV/nucleon, target-dependence of the reaction, elastic-breakup, nucleon-stripping, nucleon-removal, and complete- and incomplete-fusion cross sections is clearly explained by simple formulas. Accuracy of the Glauber model is also investigated.

  3. Absolute partial decay branching-ratios in 16O

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

    The a-transfer reaction 126C(63Li, d)168O* has been performed at a 6Li bombarding energy of 42 MeV to populate excited states in 13C and 16O. Absolute branching ratios have been unambiguously determined for states in the excitation energy range 13.85 to 15.87 MeV and reduced widths are extracted.

  4. [4-aminopyridine induced rage reaction in mice].

    PubMed

    Xu, J H; Liu, H C; Zhang, Y P

    1991-03-01

    Rage reaction was induced in mice by sc 4-aminopyridine (4-AP) 6 mg . kg-1. Mice appeared hyperreactive after 8-12 min and then squeaked and fought each other. These manifestations were most distinct in 10-30 min and subsided after 40-60 min. The occurrence of rage reaction on this dose level was around 90%. At higher doses 4-AP caused convulsions and death after evocation of rage reaction. The ED50 of 4-AP for eliciting rage reaction was 4.7 +/- 0.7 mg . kg-1 sc. No significant difference in induction of rage reaction was seen between male and female mice of different body weights. Both neuroleptic drugs (chlorpromazine, haloperidol, tarden and clozapine) and anxiolytic drugs (diazepam, chlordiazepoxide, and meprobamate) inhibited 4-AP-induced rage reaction in mice. Barbiturates, Chloral hydrate, methaqualone, morphine hydrochloride, aspirin, phenytoin sodium, diphenhydramine hydrochloride, atropine sulfate, and procaine hydrochloride did not affect rage reaction. The 4-AP-induced aggressive behavior, similar to that induced by electric footshock or isolation, has the merits of convenience to deal with and time saving. Hence we recommended it as a screening method for drugs with neuroleptic and anxiolytic activities. PMID:1685615

  5. New measurement of the α asymptotic normalization coefficient of the 1/2 + state in 17O at 6.356 MeV that dominates the 13C(α ,n ) 16O reaction rate at temperatures relevant for the s process

    NASA Astrophysics Data System (ADS)

    Avila, M. L.; Rogachev, G. V.; Koshchiy, E.; Baby, L. T.; Belarge, J.; Kemper, K. W.; Kuchera, A. N.; Santiago-Gonzalez, D.

    2015-04-01

    Background: Accurate knowledge of the 13C(α ,n ) 16O reaction cross section is important for the understanding of the s process in asymptotic giant branch stars, since it is considered to be the main source of neutrons. The subthreshold 1 /2+ state at excitation energy of 6.356 MeV in 17O has a strong influence on the reaction cross section at energies relevant for astrophysics. Several experiments have been performed to determine the contribution of this state to the 13C(α ,n ) 16O reaction rate. Nevertheless, significant discrepancies between different measurements remain. Purpose: The aim of this work is to investigate these discrepancies. Method: An 8 MeV 13C beam (below the Coulomb barrier) was used to study the α -transfer reaction 6Li(13C ,d ) 17O . Results: The squared Coulomb-modified asymptotic normalization coefficient of the 1 /2+ state in 17O measured in this work is (C˜α-13C17O(1/2 +)) 2=3.6 ±0.7 fm-1 . Conclusions: Discrepancy between the results of α -transfer experiments have been resolved. However, some discrepancy with the most recent measurement using the Trojan Horse method remains.

  6. 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.

  7. Importance of the energy-dependent geometry in the 16O+ 16O optical model potential

    NASA Astrophysics Data System (ADS)

    Pantis, G.; Ioannidis, K.; Poirier, P.

    1985-08-01

    Optical model potentials with various forms of energy-dependent geometry have been considered for the description of 16O+ 16O elastic scattering. It is shown that the variation with energy of the imaginary radius leads to a reasonable fit of the cross-section data, throughout the energy range.

  8. 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.

  9. 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. PMID:21079822

  10. Permeability Changes in Reaction Induced Fracturing

    NASA Astrophysics Data System (ADS)

    Ulven, Ole Ivar; Malthe-Sørenssen, Anders; Kalia, Rajiv

    2013-04-01

    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.[4], serpentinization and carbonation of peridotite by Rudge et al.[3] and replacement reactions in silica-poor igneous rocks by Jamtveit et al.[1]. 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 reaction rate, as summarised by Kelemen et al.[2]. Røyne et al.[4] have shown that transport in fractures will have an effect on the fracture pattern formed. 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 under compression, and it remains an open question how sensitive a fracture pattern is to permeability changes. In this work, we study the permeability of fractures formed under compression, and we use a 2D discrete element model to study the fracture patterns and total reaction rates achieved with different permeabilities. We achieve an improved understanding of the feedback processes in reaction-driven fracturing, thus improving our ability to decide whether industrial scale CO2 sequestration in ultramafic rock is a viable option for long-term handling of CO2. References [1] Jamtveit, B, Putnis, C. V., and Malthe-Sørenssen, A., "Reaction induced fracturing during replacement processes," Contrib. Mineral Petrol. 157, 2009, pp. 127 - 133. [2] Kelemen, P., Matter, J., Streit, E. E., Rudge, J. F., Curry, W. B., and Blusztajn, J., "Rates and Mechanisms of Mineral Carbonation in Peridotite: Natural Processes and Recipes for Enhanced, in situ CO2 Capture and Storage," Annu. Rev. Earth Planet. Sci. 2011. 39:545-76. [3] Rudge, J. F., Kelemen, P. B., and

  11. Nuclear reactions induced by a pyroelectric accelerator.

    PubMed

    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)]. PMID:16486940

  12. 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.

  13. 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.

  14. Does a 4-α linear chain exist in 16O?

    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.

    2012-09-01

    The12C(4He,8Be)8Be reaction has been measured with a beam energy ranging from 12.2 to 20.0 MeV. The α-particles emitted in the decay of 8Be were detected in an array of four double sided silicon strip detectors. The excitation function for events in which the 8Be centre of mass angle θcm = 90° provides evidence that the previously observed 6+ resonance at an excitation energy of 19.35 MeV in 16O is a 6+ doublet, with members at ~ 19.30 and 19.37 MeV.

  15. CW CO2 Laser Induced Chemical Reactions

    NASA Astrophysics Data System (ADS)

    Pola, Joseph

    1989-05-01

    CW CO2 laser driven reactions between sulfur hexafluoride and carbon oxide, carbon suboxide, carbonyl sulfide and carbon disulfide proceed at subatmospheric pressures and yield fluorinated carbon compounds and sulfur tetrafluoride. CW CO2 laser driven reactions of organic compounds in the presence of energy-conveying sulfur hexafluoride show reaction course different from that normally observed due to elimination of reactor hot surface effects. The examples concern the decomposition of polychlorohydrocarbons, 2-nitropropane, tert.-butylamine, allyl chloride, spirohexane, isobornyl acetate and the oxidation of haloolefins. CW CO2 laser induced fragmentation of 1-methyl-l-silacyclobutanes and 4-silaspiro(3.4)octane in the presence of sulfur hexafluoride is an effective way for preparation and deposition of stable organosilicon polymers.

  16. 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. PMID:24607449

  17. 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.

  18. 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

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

    SciTech Connect

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

    2011-06-15

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

  20. 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.

  1. Alternate Alpha Induced Reactions for NIF Radiochemistry

    SciTech Connect

    Shaughnessy, D A; Moody, K J; Bernstein, L A

    2010-02-26

    Radiochemical analysis of NIF capsule residues has been identified as a potential diagnostic of NIF capsule performance. In particular, alpha-induced nuclear reactions that occur on tracer elements added to the NIF capsule have been shown through simulation to be a very sensitive diagnostic for mix. The short range of the alpha particles makes them representative of the hot spot where they are created through the fusion of deuterium and tritium. Reactions on elements doped into the innermost part of the capsule ablator would therefore be sensitive to material that had mixed into the hot spot. Radiochemical determinations of activated detector elements may perhaps be the only true measure of mix that occurs in a NIF capsule, particularly in cases when the capsule fails.

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

    SciTech Connect

    Berman, M.R.

    1981-01-01

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

  3. 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.

  4. 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

  5. Evidence for tetrahedral symmetry in (16)O.

    PubMed

    Bijker, R; Iachello, F

    2014-04-18

    We derive the rotation-vibration spectrum of a 4α configuration with tetrahedral symmetry Td and show evidence for the occurrence of this symmetry in the low-lying spectrum of (16)O. All vibrational states with A, E, and F symmetry appear to have been observed as well as the rotational bands with LP=0+, 3-, 4+, 6+ on the A states and part of the rotational bands built on the E, F states. We derive analytic expressions for the form factors and B(EL) values of the ground-state rotational band and show that the measured values support the tetrahedral symmetry of this band. PMID:24785032

  6. Dependence of the 16O+16O nuclear potential on nuclear incompressibility

    NASA Astrophysics Data System (ADS)

    Hossain, S.; Tariq, A. S. B.; Nilima, Athoy; Islam, M. Sujan; Majumder, R.; Sayed, M. A.; Billah, M. M.; Azad, M. M. B.; Uddin, M. A.; Reichstein, I.; Malik, F. B.; Basak, A. K.

    2015-06-01

    Nonmonotonic (NM) nucleus-nucleus potentials from the energy-density functional (EDF) theory including the Pauli principle have been considered for the nuclear incompressibility K in the range 188-266 MeV. The experimental cross sections of the 16O+16O elastic scattering over the 31-350 MeV incident energies have been analyzed in the optical model using the NM potentials. Sensitivity of K on the elastic scattering data is studied and its value for infinite cold nuclear matter deduced to be 222 ±5 MeV .

  7. 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

  8. Study of Rainbow Scattering in 16O + 14C System

    NASA Astrophysics Data System (ADS)

    Demyanova, A. S.; Glukhov, Yu. A.; Ogloblin, A. A.; Trzaska, W.; Bohlen, H. G.; Oertzen, W. Von; Goncharov, S. A.; Izadpanakh, A.; Maslov, V. A.; Penionzhkevich, Yu. E.; Sobolev, Yu. G.; Khlebnikov, S. V.; Tyurin, G. P.

    2005-09-01

    We carried out new measurements of the 16O+14C differential cross-sections at the 16O energy 281 MeV in the large angles interval at the Jyvaskyla University cyclotron and at the smallest angles at the cyclotron of Hahn-Meitner institute. The results of the experiment showed that clear rainbow structure in 16O + 14C scattering really takes place. The observed position of the main Airy minimum predicted but not observed in previous measurements fits well to the empirical systematization "angle - inverse energy", obtained for the system 16O + 12C.

  9. 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.

  10. Nefazadone-induced acute dystonic reaction.

    PubMed

    Burda, A; Webster, K; Leikin, J B; Chan, S B; Stokes, K A

    1999-10-01

    A 53-y-o patient presented approximately 2 h after taking her first dose of nefazadone. Chief complaint was lip smacking with hand and arm gesturing. The patient also took 25 mg meclizine which she had used before with no adverse effects. Diphenhydramine followed by benztropine led to resolution of symptoms within 1 h. Patient subsequently used meclizine with no untoward reactions. Nefazadone should be added to the list of agents that cause acute dystonic reactions. PMID:10509438

  11. 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.

  12. Ofloxacin Induced Cutaneous Reactions in Children

    PubMed Central

    Mishra, Sailen Kumar; Rath, Bandana; Rath, Saroj Sekhar

    2015-01-01

    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. PMID:26266136

  13. Cross sections of neutron-induced reactions

    SciTech Connect

    Mukhopadhyay, Tapan; Lahiri, Joydev; Basu, D. N.

    2010-10-15

    We study the properties of the neutron-nucleus total and reaction cross sections for several nuclei. We have applied an analytical model, the nuclear Ramsauer model, justified it from the nuclear reaction theory approach, and extracted the values of 12 parameters used in the model. The given parametrization has an advantage as phenomenological optical model potentials are limited up to 150-200 MeV. The present model provides good estimates of the total cross sections for several nuclei particularly at high energies.

  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. 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

  16. Alpha-induced reactions in iridium

    SciTech Connect

    Bhardwaj, M.K.; Rizvi, I.A.; Chaubey, A.K. )

    1992-05-01

    The excitation function of ({alpha},{ital xn}) reactions on {sup 191}Ir (abundance 37.3%) and on {sup 193}Ir (abundance 62.7%) has been measured for the 17--55 MeV alpha-particle bombarding energy range. The stacked foil activation technique and {gamma}-ray spectroscopy were used to determine the cross sections. The experimental data were compared with calculated values obtained by means of a geometry-dependent hybrid model. The initial exciton number {ital n}{sub 0}=4 with {ital n}=2, {ital p}=2, and {ital h}=0 gives the best agreements with the presently measured results. To calculate the excitation function theoretically a computer code was used. This set of excitation functions provides a data basis for probing the validity of combined equilibrium and preequilibrium reaction models in a considerable energy range.

  17. 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

  18. 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

  19. Shock-induced reaction synthesis (SRS) of nickel aluminides

    SciTech Connect

    Thadhani, N.N.; Work, S. , New Mexico Tech, Socorro, New Mexico 87801 ); Graham, R.A.; Hammetter, W.F. )

    1992-05-01

    Shock-induced chemical reactions between nickel and aluminum powders (mixed in Ni{sub 3}Al stoichiometry) are used for the synthesis of nickel aluminides. It is shown that the extent of shock-induced chemical reactions and the nature of the shock-synthesized products are influenced by the morphology of the starting powders. Irregular (flaky type) and fine morphologies of the powders undergo complete reactions in contrast to partial reactions occurring in coarse and uniform morphology powders under identical shock loading conditions. Furthermore, irregular morphology powders result in the formation of the equiatomic (B2 phase) NiAl compound while the Ni{sub 3}Al (L1{sub 2} phase) compound is the reaction product with coarse and regular morphology powders. Shock-induced reaction synthesis can be characterized as a bulk reaction process involving an intense mechanochemical'' mechanism. It is a process in which shock compression induces fluid-like plastic flow and mixing, and enhances the reactivity due to the introduction of defects and cleansing of particle surfaces, which strongly influence the synthesis process.

  20. 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.

  1. 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

  2. CO Self-Shielding as a Mechanism to Make 16O-Enriched Solids in the Solar Nebula

    NASA Astrophysics Data System (ADS)

    Nuth, Joseph A., III; Johnson, Natasha M.; Hill, Hugh G. M.

    2014-05-01

    Photochemical self-shielding of CO has been proposed as a mechanism to produce solids observed in the modern, 16O-depleted solar system. This is distinct from the relatively 16O-enriched composition of the solar nebula, as demonstrated by the oxygen isotopic composition of the contemporary sun. While supporting the idea that self-shielding can produce local enhancements in 16O-depleted solids, we argue that complementary enhancements of 16O-enriched solids can also be produced via C16O-based, Fischer-Tropsch type (FTT) catalytic processes that could produce much of the carbonaceous feedstock incorporated into accreting planetesimals. Local enhancements could explain observed 16O enrichment in calcium-aluminum-rich inclusions (CAIs), such as those from the meteorite, Isheyevo (CH/CHb), as well as in chondrules from the meteorite, Acfer 214 (CH3). CO self-shielding results in an overall increase in the 17O and 18O content of nebular solids only to the extent that there is a net loss of C16O from the solar nebula. In contrast, if C16O reacts in the nebula to produce organics and water then the net effect of the self-shielding process will be negligible for the average oxygen isotopic content of nebular solids and other mechanisms must be sought to produce the observed dichotomy between oxygen in the Sun and that in meteorites and the terrestrial planets. This illustrates that the formation and metamorphism of rocks and organics need to be considered in tandem rather than as isolated reaction networks.

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. Tensor analyzing powers and energy dependence of the {sup 7}Li+{sup 16}O interaction

    SciTech Connect

    Rudchik, A. T.; Rudchik, A. A.; Chesnokova, V. D.; Kyryanchuk, V. M.; Ponkratenko, O. A.; Kemper, K. W.; Crisp, A. M.; Marechal, F.; Roeder, B. T.; Momotyuk, O. A.; Rusek, K.

    2007-02-15

    The differential cross section angular distribution and the analyzing powers {sup T}T{sub 10},{sup T}T{sub 20}, for {sup 7}Li+{sup 16}O elastic scattering were measured at E{sub lab}({sup 7}Li(vector sign)) = 42 MeV. These and previously published {sup 7}Li+{sup 16}O scattering data measured at E{sub c.m.} = 6.26-34.78 MeV were analyzed with the optical model and coupled-reaction channels (CRC) methods to determine the energy dependence of the parameters of the scattering potential. It was found that the optical model potentials are energy independent for {sup 7}Li laboratory bombarding energies above 28 MeV, except for a slight decrease in the real potential strength as the bombarding energy increases. The calculations presented show that the tensor analyzing power {sup T}T{sub 20} arises from a coherent combination of contributions from the ground-state reorientation and central scattering potential. The energy-dependent CRC potentials were shown to describe the data for the {sup 16}O({sup 7}Li,t){sup 20}Ne reaction.

  8. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2000-09-01

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

  10. Photo- and neutrino-induced reactions for SNe nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Shima, Tatsushi

    2014-09-01

    Neutrino-induced nuclear reactions are considered to play important roles in the dynamics of supernova explosions and in supernova nucleosynthesis. For example, neutrino-inelastic scattering off light nuclei are supposed to assist the explosion by supplying the kinetic energy to the outgoing matters. The neutrino-nucleus reactions via the neutral and charged current of the weak interaction are the key reactions in the r-process nucleosynthesis in neutrino-driven wind. To quantitatively understand those phenomena, precise data of the neutrino-nucleus reaction rates are indispensable. Recently developed secondary particle beams provide good experimental opportunities for determining the neutrino-nucleus reaction rates. A quasi-monochromatic laser Compton-scattered (LCS) photon beam is useful for studying the photonuclear reactions which are the direct analogue of the neutrino inelastic scatterings caused by the weak neutral current. On the other hand, real neutrino beams are ideal tools to directly measure the absolute neutrino-nucleus reaction rates. Another interesting probe will be the nuclear muon-capture reaction, because it can be applied for measurement of the targets with very small quantities thanks to its large capture probability. In this talk recent progress in ongoing experiments with LCS gamma-rays and muon beams will be presented. A new plan for direct measurement of the neutrino-nucleus reactions with an accelerator-driven neutrino beam will be also discussed.

  11. 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.

  12. Thermally Induced And Base Catalyzed Reactions Of Naphthoquinone Diazides

    NASA Astrophysics Data System (ADS)

    Koshiba, Mitsunobu; Murata, Makoto; Matsui, Mariko; Harita, Yoshiyuki

    1988-01-01

    Thermally induced and base catalyzed reactions of a phenol ester of 1,2-naphthoquinone-diazide-5-sulfonic acid (DAM) with p-cresol were investigated. In total seven reaction products were obtained for the thermally induced reaction. The three major products, TR--F4, TR-F6 and TR-F7, were isolated and their structures were determined by means of several advanced spectroscopic techniques like Fourier transform nuclear magnetic resonance (FTNMR) and field desorption mass spectroscopy (FD-MS). Besides a cresol ester of indenecarboxylic acid (TR-F6) and an azo compound which contains two DAM originated moieties and cresol (TR-F7), the formation of a novel compound was found; a phenol ester of 2-cresyl-l-naphthol-5-sulfonic acid. On the other hand, four reaction products were found in the base (a 2.38wt% tetramethylammonium hydroxide aq. solution) catalyzed reaction products of DAM with p-cresol, and two major products, BC-Fl and BC-F3, which appeared at the initial stage of the reaction were isolated. The structure determination of the two major products was carried out in the same manner as described above. It was discovered that BC-Fl was a cresol ester of 1-naphthol while BC-F3 was an azoxy compound. Brief discussions will be made on those reactions of naphthoquinone diazides with a matrix novolak resin with reference to the results obtained by the present study.

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

    SciTech Connect

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

    2015-02-24

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

  14. [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.

  15. On reaction mechanisms involved in the deuteron-induced surrogate reactions

    NASA Astrophysics Data System (ADS)

    Avrigeanu, M.; Avrigeanu, V.; Mǎnǎilescu, C.

    2015-02-01

    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.

  16. 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. PMID:25345596

  17. 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.

  18. 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.

  19. 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. PMID:25308653

  20. 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. PMID:15800617

  1. Neutron-induced reactions in tissue-resident elements

    SciTech Connect

    Herling, G.H.; Bassel, R.H.; Adams, J.H.; Fraser, W.A.

    1981-07-08

    Kerma-to-fluence ratios have been calculated for neutrons with energies between 20 and 60 MeV incident upon 1H, 12C, 14N, and 16O. The following charged particles have been taken into account: protons, deuterons, alpha particles, and heavy recoils. Results are presented for NE-213 plastic, muscle, and tissue-equivalent plastic.

  2. a Study of the Mechanism of OXYGEN-16-INDUCED Reactions Between 140 and 315 Mev Incident Energies.

    NASA Astrophysics Data System (ADS)

    Awes, Terry Clayton

    Reactions induced by ('16)O ions on ('238)U at incident energies of E/A = 20 MeV have been studied. In coincidence with fission fragments, projectile residues (Li,...,O) have been measured near the grazing angle and double differential cross sections have been measured for energetic p,d,t, and (alpha)-particles. The folding-angle between the two coincident fission fragments is shown to provide information on the linear momentum transfer to the target nucleus. The emission of energetic light particles into the forward direction is shown to be an important aspect of the mechanism of projectile residue emission. However, light particles emitted in coincidence with projectile residues are not the result of a simple quasi-elastic breakup of the projectile. This is shown by a kinematical analysis which demonstrates that a large amount of linear momentum is transferred to the target residue prior to fission. Using the folding-angle information in coincidence with the observation of energetic light particles, it is concluded that the majority of these particles result from fusion-like "central" collisions with no projectile residue in the exit channel. It is suggested that these particles most likely are emitted during the early stages of the reaction. Double differential cross sections have also been measured for energetic p,d,t, and (alpha)-particles emitted in ('16)O-induced reactions on targets of Al, 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 trend 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 rotating hot spot

  3. Neutrino magnetic moment effects in neutrino nucleus reactions

    SciTech Connect

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

    1995-10-01

    Some low energy neutrino nucleus reactions induced by neutrinos (antineutrinos) having a magnetic moment of the order of 10{sup {minus}9}{minus}10{sup {minus}10} Bohr magneton are studied. It is found that in the case of {sup 4}He, {sup 12}C, and {sup 16}O, the detection of very low energy scalar and isoscalar elastic and inelastic reactions induced by the isoscalar vector currents can provide a better limit on the neutrino magnetic moment.

  4. 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.; Murcray, F. J.

    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.

  5. Alpha Induced Reaction Cross Section Calculations of Tantalum Nucleus

    NASA Astrophysics Data System (ADS)

    Tel, E.; Ugur, F. A.; Gokce, A. A.

    2013-04-01

    The fusion energy is attractive as an energy source because the fusion will not produce CO2 or SO2 and so fusion will not contribute to environmental problems, such as particulate pollution and excessive CO2 in the atmosphere. The fusion reaction does not produce radioactive nuclides and it is not self-sustaining, as is a fission reaction when a critical mass of fissionable material is assembled. Since the fusion reaction is easily and quickly quenched the primary sources of heat to drive such an accident are heat from radioactive decay and heat from chemical reactions. Both the magnitude and time dependence of the generation of heat from radioactive decay can be controlled by proper selection and design of materials. Tantalum is one of the candidate materials for the first wall of fusion reactors and for component parts of irradiation chambers. Accurate experimental cross-section data of alpha induced reactions on Tantalum are also of great importance for thermonuclear reaction rate determinations since the models used in the study of stellar nucleosynthesis are strongly dependent on these rates (Santos et al. in J Phys G 26:301, 2000). In this study, neutron-production cross sections for target nuclei 181Ta have been investigated up to 100 MeV alpha energy. The excitation functions for (α, xn) reactions (x = 1, 2, 3) have been calculated by pre-equilibrium reaction mechanism. And also neutron emission spectra for 181Ta (α, xn) reactions at 26.8 and 45.2 MeV have been calculated. The mean free path multiplier parameters has been investigated. The pre-equilibrium results have been calculated by using the hybrid model, the geometry dependent hybrid (GDH) model. Calculation results have been also compared with the available measurements in literature.

  6. Fatal anaphylactoid reaction associated with heparin-induced thrombocytopenia.

    PubMed

    Singla, Atul; Amini, Mohammad R; Alpert, Martin A; Gornik, Heather L

    2013-06-01

    Acute systemic (anaphylaxis and anaphylactoid) reactions have been well described in patients with heparin-induced thrombocytopenia (HIT). Both necrotizing and non-necrotizing skin lesions at heparin injection sites have been reported and may occur in 10-20% of patients with HIT. We report herein a patient treated with subcutaneous enoxaparin sodium who developed non-necrotizing erythematous skin lesions at enoxaparin sodium injection sites. A subsequent intravenous bolus of unfractionated heparin produced a fatal anaphylactoid reaction. This suggests that caution should be exercised in the administration of intravenous heparin to patients with non-necrotizing erythematous skin lesions at prior heparin injection sites. PMID:23579400

  7. Heparin-induced anaphylactoid reaction associated with heparin-induced thrombocytopenia in the ED.

    PubMed

    Foreman, Juron S; Daniels, Lauren M; Stettner, Edward A

    2014-12-01

    Although rare, heparin-induced anaphylactic and anaphylactoid reactions have been previously described in the literature. We present a case of a patient who presented to the emergency department with dyspnea and was subsequently diagnosed with an acute pulmonary venous thromboembolism. Shortly after being started on intravenous unfractionated heparin, she developed sudden cardiovascular collapse leading to a cardiopulmonary arrest. She was successfully resuscitated and, after further diagnostic evaluation, was found to have developed a heparin-induced anaphylactoid reaction. PMID:25097093

  8. 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

  9. Investigation of the 4-α linear chain state in 16O

    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.

    2013-12-01

    The 12C(4He,8Be)8Be and 12C(4He,12C* → 8Be+α)α reactions have been measured with beam energies ranging from 12.2 to 20.0 MeV. The α particles emitted directly and following the decay of 8Be and 12C* were detected in an array of four double sided silicon strip detectors. An analysis of the angular distributions obtained for the 12C(4He,8Be)8Be channel provides no evidence to support the previously proposed rotational structure consisting of a rigid, linear, arrangement of four α particles in 16O.

  10. LiCe9Mo16O35

    PubMed Central

    Gougeon, Patrick; Gall, Philippe

    2012-01-01

    The structure of lithium nona­cerium hexa­deca­molybdenum penta­trideca­oxide, LiCe9Mo16O35, is isotypic with LiNd9Mo16O35 [Gougeon Gall, Cuny, Gautier, Le Polles, Delevoye & Trebosc (2011 ▶). Chem. Eur. J. 17, 13806–13813]. It is characterized by Mo16O26 iO10 a units (where i = inner and a = apical) containing Mo16 clusters that share some of their O atoms to form infinite molybdenum cluster chains running parallel to the b axis and separated by Li+ and Ce3+ cations. The Mo16 cluster units are centred at Wyckoff positions 2c and have point-group symmetry 2/m. The Li+ atom, in a flattened octa­hedron of O atoms, is in a 2a Wyckoff position with 2/m symmetry. The Ce3+ cations have coordination numbers to the O atoms of 6, 9 or 10. Two Ce, two Mo and five O atoms lie on sites with m symmetry (Wyckoff site 4i), and one Ce and one O atom on sites with 2/m symmetry (Wyckoff sites 2b and 2d, respectively). PMID:22412396

  11. Discreteness-induced transitions in multibody reaction systems.

    PubMed

    Saito, Yohei; Sughiyama, Yuki; Kaneko, Kunihiko; Kobayashi, Tetsuya J

    2016-08-01

    A decrease in system size can induce qualitatively different behavior compared to the macroscopic behavior of the corresponding large-size system. The mechanisms of this transition, which is known as the small-size transition, can be attributed to either a relative increase in the noise intensity or to the discreteness of the state space due to the small system size. The former mechanism has been intensively investigated using several toy and realistic models. However, the latter has rarely been analyzed and is sometimes confused with the former, because a toy model that extracts the essence of the discreteness-induced transition mechanism is lacking. In this work, we propose a one- and three-body reaction system as a minimal model of the discreteness-induced transition and derive the conditions under which this transition occurs in more complex systems. This work enriches our understanding of the influence of small system size on system behavior. PMID:27627279

  12. Including higher energy data in the R-matrix extrapolation of 12C(α , γ) 16O

    NASA Astrophysics Data System (ADS)

    Deboer, R.; Uberseder, E.; Azuma, R. E.; Best, A.; Brune, C.; Goerres, J.; Sayre, D.; Smith, K.; Wiescher, M.

    2015-10-01

    The phenomenological R-matrix technique has proved to be very successful in describing the cross sections of interest to nuclear astrophysics. One of the key reactions is 12C(α , γ) 16O, which has frequently been analyzed using R-matrix but usually over a limited energy range. This talk will present an analysis that, for the first time, extends above the proton and α1 separation energies taking advantage of a large amount of additional data. The analysis uses the new publicly released JINA R-matrix code AZURE2. The traditional reaction channels of 12C(α , γ) 16O, 12C(α ,α0) 12, and 16N(βα) 12C are included but are now accompanied by the higher energy reactions. By explicitly including higher energy levels, the uncertainty in the extrapolation of the cross section is significantly reduced. This is accomplished by more stringent constraints on interference combination and background poles by the additional higher energy data and by considering new information about subthresold states from transfer reactions. The result is the most comprehensive R-matrix analysis of the 12C(α , γ) 16O reaction to date. This research was supported in part by the ND CRC and funded by the NSF through Grant No. Phys-0758100, and JINA through Grant No. Phys-0822648.

  13. Preresidue'' light charged particles from [sup 28]Si+[sup 165]Ho, [sup 16]O+[sup 197]Au, and [sup 16]O+[sup 208]Pb fusion

    SciTech Connect

    Fineman, B.J.; Brinkmann, K.; Caraley, A.L.; Gan, N.; McGrath, R.L.; Velkovska, J. )

    1994-10-01

    Proton and [alpha]-particle spectral shapes and multiplicities have been measured in coincidence with evaporation residues from 145 to 220 MeV [sup 28]Si+[sup 165]Ho and 115 and 140 MeV [sup 16]O+[sup 197]Au,[sup 208]Pb fusion reactions. Evaporation residues were separated using an electrostatic deflector and detected with large area surface barrier detectors. Light charged particles were detected at forward and backward angles with 14 single NaI detectors. In the context of the statistical model, the charged particle spectra provide information about the shapes and level densities of the emitting systems. Deformed emitters are inferred, and to a varying degree, an energy-dependent level density parameter is compatible with the data in each of the three cases. Implications for current fusion and fission dynamics studies are discussed.

  14. Laser-induced reaction alumina coating on ceramic composite

    NASA Astrophysics Data System (ADS)

    Xiao, Chenghe

    Silicon carbide ceramics are susceptible to corrosion by certain industrial furnace environments. It is also true for a new class of silicon carbide-particulate reinforced alumina-matrix composite (SiCsb(P)Alsb2Osb3) since it contains more than 55% of SiC particulate within the composite. This behavior would limit the use of SiCsb(P)Alsb2Osb3 composites in ceramic heat exchangers. Because oxide ceramics corrode substantially less in the same environments, a laser-induced reaction alumina coating technique has been developed for improving corrosion resistance of the SiCsb(P)Alsb2Osb3 composite. Specimens with and without the laser-induced reaction alumina coating were subjected to corrosion testing at 1200sp°C in an air atmosphere containing Nasb2COsb3 for 50 ˜ 200 hours. Corroded specimens were characterized via x-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectrometer (EDS). The uncoated SiCsbP/Alsb2Osb3 composite samples experienced an initial increase in weight during the exposure to Nasb2COsb3 at 1200sp°C due to the oxidation of residual aluminum metal in the composite. There was no significant weight change difference experienced during exposure times between 50 and 200 hours. The oxidation layer formed on the as-received composite surface consisted of Si and Alsb2Osb3 (after washing with a HF solution). The oxidation layer grew outward and inward from the original surface of the composite. The growth rate in the outward direction was faster than in the inward direction. The formation of the Si/Alsb2Osb3 oxidation layer on the as-received composite was nonuniform, and localized corrosion was observed. The coated samples experienced very little mass increase. The laser-induced reaction alumina coating effectively provided protection for the SiCsbP/Alsb2Osb3 composite by keeping the corrodents from contacting the composite and by the formation of some refractory compounds such as Nasb2OAlsb2Osb3SiOsb2 and Nasb2Alsb{22}Osb

  15. (Studies of heavy-ion induced reactions): Annual progress report

    SciTech Connect

    Mignerey, A.C.

    1986-10-01

    An experiment was performed at the Lawrence Berkeley Laboratory Bevalac, extending previous studies using inverse reactions to 50 MeV/u /sup 139/La incident on targets of C and Al. Studies of excitation energy division in lower energy division in lower energy heavy-ion reactions were furthered using kinematic coincidences to measure the excitation energies of primary products in the Fe + Ho reaction at 12 MeV/u. These results will provide important systematics for comparisons with previous measurements at 9 MeV/u on the same system and at 15 MeV/u on the Fe + Fe and Fe + U systems. Also studied were different aspects of 15 MeV/u Fe-induced reactions, with experiments performed at the Oak Ridge HHIRF. The first three contributions of this report constitute a major portion of the results from this research. Finally, at the Lawrence Berkeley Laboratory Bevalac a large detector array for coincident detection of fragmentation products in heavy-ion collisions below 100 MeV/u is being built. A list of publications, personnel, and activities is provided.

  16. 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. PMID:21175859

  17. Two-photon-induced cycloreversion reaction of chalcone photodimers

    NASA Astrophysics Data System (ADS)

    Träger, J.; Härtner, S.; Heinzer, J.; Kim, H.-C.; Hampp, N.

    2008-04-01

    The photocleavage reaction of chalcone photodimers has been studied using a two-photon process. For this purpose, a novel chalcone dimer has been synthesized as a low molecular weight model substance for polymer bound chalcones and its photochemistry triggered by two-photon-absorption (2PA) has been investigated using a pulsed frequency-doubled Nd:YAG-laser. The 2PA-induced cycloreversion reaction selectively leads to the cleavage of the chalcone photodimers resulting in the formation of monomeric chalcone molecules. Hence, as an application chalcones can be used as a photosensitive linker which can be cleaved beyond an UV-absorbing barrier. The 2PA cross section of the chalcone photodimer was determined to be of 1.1 × 10 -49 cm 4 s photon -1 (11 GM).

  18. Establishing a theory for deuteron induced surrogate reactions

    DOE PAGESBeta

    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

  19. 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.

  20. Establishing a theory for deuteron-induced surrogate reactions

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

    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 93Nb(d ,p )X at Ed=15 and 25 MeV and are able to obtain a good description of the data. We 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. Finally, we make important predictions for the relative contributions of elastic breakup and nonelastic breakup and call for elastic-breakup measurements to further constrain our model.

  1. Reaction mechanism studies of heavy ion induced nuclear reactions. Annual progress report

    SciTech Connect

    Mignerey, A.C.

    1981-07-01

    The research summarized in this report was performed during the period August 1, 1980 to June 30, 1981. The experimental emphasis in the heavy-ion-induced reaction studies continues to be discrete charge and mass resolution of all projectile-like fragments measured. In an experiment performed at the Argonne National Laboratory Superconducting LINAC, the /sup 37/Cl beam was used to bombard targets of /sup 40/Ca and /sup 209/Bi. This experiment is compared to results of our previous /sup 56/Fe-induced experiments. Attempts were made to extend the /sup 56/Fe reactions to lower energies at the Lawrence Berkeley Laboratory SuperHILAC. In a desire to improve the mass and charge resolution of previous experiments we tried a time-of-flight telescope employing both a channel-plate start and stop signal. This was backed by an ion chamber ..delta..E and silicon E detector. The operational difficulties encountered are being corrected and we hope to have a reliable system ready this fall. Studies of target fragmentation in /sup 4/He-induced reactions are continuing via experiments and model calculations. The program which began at the University of Maryland Cyclotron has been continued at the Indiana University Cyclotron with 120 and 200 MeV /sup 4/He incident on /sup 12/C and /sup 27/Al targets. While the Indiana data are currently being analyzed and no results are yet available, a summary of the Maryland work is given. Also presented in this section are the model calculations used to describe the data. 28 refs.

  2. Nuclear reactions induced by. pi. /sup -/ at rest

    SciTech Connect

    Gadioli, E.; Gadioli Erba, E.

    1987-08-01

    The experimental information on reactions induced by stopped ..pi../sup -/ absorbed in nuclei is critically reviewed. Evidence for the presence of ..cap alpha..-cluster absorptions is presented and arguments are given to show that approx. =25% of ..pi../sup -/ absorptions are of this kind. In the case of two-nucleon absorption, the existing experimental information concerning the ratio of n-p to p-p absorbing pairs is discussed. Calculations of particle spectra and residue spallation yield distributions that, in addition to two-nucleon absorption, include ..cap alpha..-cluster absorption are presented, and it is shown that a satisfactory reproduction of the data is achieved.

  3. 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.

  4. Shock induced chemical reactions in energetic structural materials

    NASA Astrophysics Data System (ADS)

    Reding, Derek J.

    Energetic structural materials (ESMs) constitute a new class of materials that provide dual functions of strength and energetic characteristics. ESMs are typically composed of micron-scale or nano-scale intermetallic mixtures or mixtures of metals and metal oxides, polymer binders, and structural reinforcements. Voids are included to produce a composite with favorable chemical reaction characteristics. In this thesis, a continuum approach is used to simulate gas-gun or explosive loading experiments where a strong shock is induced in the ESM by an impacting plate. Algorithms are developed to obtain equations of state of mixtures. It is usually assumed that the shock loading increases the energy of the ESM and causes the ESM to reach the transition state. It is also assumed that the activation energy needed to reach the transition state is a function of the temperature of the mixture. In this thesis, it is proposed that the activation energy is a function of temperature and the stress state of the mixture. The incorporation of such an activation energy is selected in this thesis. Then, a multi-scale chemical reaction model for a heterogeneous mixture is introduced. This model incorporates reaction initiation, propagation, and extent of completed reaction in spatially heterogeneous distributions of reactants. A new model is proposed for the pore collapse of mixtures. This model is formulated by modifying the Carol, Holt, and Nesterenko spherically symmetric model to include mixtures and compressibility effects. Uncertainties in the model result from assumptions in formulating the models for continuum relationships and chemical reactions in mixtures that are distributed heterogeneously in space and in numerical integration of the resulting equations. It is important to quantify these uncertainties. In this thesis, such an uncertainty quantification is investigated by systematically identifying the physical processes that occur during shock compression of ESMs which are

  5. Nucleation and reaction rates controlled by local reaction volume and reaction-induced stress - spinel layer growth as an example

    NASA Astrophysics Data System (ADS)

    Götze, Lutz C.; Milke, Ralf; Dohmen, Ralf; Wirth, Richard

    2014-05-01

    %) and a positive volume change at the Sp-Cor interface (by +17 %). We observed in TEM images formation of porosity at the Sp-Per substrate interface and lattice strain in the polycrystalline corundum substrate at the Sp-Cor substrate interface, both observations being fully in line with the respective local volume changes. We infer that the local stress field between the growing reaction layer and the rigid single crystal substrate is responsible for the dramatic effect on both the nucleation and reaction rates. With respect to minerals growing at dry conditions in the Earth's crust (granulite facies) we infer that rates of reactions might strongly depend on local volume changes at interfaces, that reactions are impeded by compressive reaction-induced stress applied to rigid neighboring grains, and that nucleation of thermodynamically stable phases on grain boundaries might be suppressed by a positive reaction volume.

  6. Detailed study for 16O → 12C + α and 12C → 11B + p spectroscopic factors

    NASA Astrophysics Data System (ADS)

    Hamada, Sh.; Burtebayev, N.; Amangeldi, N.

    2014-10-01

    We have measured the angular distributions for 16O elastically scattered on 12C nuclei at energy 28 MeV and also for 12C ion beam elastically scattered on 11B target nuclei at energy 18 MeV. These measurements were performed in the cyclotron DC-60 INP NNC RK. Calculations were performed using both empirical Woods-Saxon and double folding optical model potentials. Both elastic scattering and transfer reaction were taken into consideration. We have extracted the spectroscopic factors for the configurations 16O → 12C + α and 12C → 11B + p and compared them with other calculated or extracted values at different energies from literature. The extracted spectroscopic factor for the configuration 12C → 11B + p from the current work is in the range 2.7-3.1, which is very close to Cohen-Kurath prediction. While for the configuration 16O → 12C + α, spectroscopic factors show fluctuation with energy which could be due to the well-known resonant-like behavior observed in 16O + 12C excitation function.

  7. Mass and charge distributions in Fe-induced reactions

    SciTech Connect

    Madani, H.; Mignerey, A.C.; Marchetti, A.A.; Weston-Dawkes, A.P.; Kehoe, W.L.; Obenshain, F.

    1995-02-21

    The charge and mass of the projectile-like fragments produced in the 12-MeV/nucleon {sup 56}Fe + {sup 165}Ho reaction were measured at a laboratory scattering angle of 16 degrees. The mass and charge distributions of the projectile-like fragments were generated as a function of total kinetic energy loss (TKEL), and characterized by their neutron and proton centroids and variances, and correlation factors. A weak drift of the system towards mass asymmetry, opposite to the direction which minimizes the potential energy of the composite system, was observed. The increase in the variances with energy loss is consistent with a nucleon exchange mechanism as a means for energy dissipation. Predictions of two nucleon exchange models, Randrup`s and, Tassan-Got`s models, are compared to the experimental results of the 672-MeV {sup 56}Fe + {sup 165}Ho reaction and to other Fe-induced reactions. The proton and neutron centroids were found to be generally better reproduced by Tassan-Got`s model than by Randrup`s model. The variances and correlation factor are well reproduced for asymmetric systems by both models.

  8. 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.

  9. Clinical Features of Oxaliplatin Induced Hypersensitivity Reactions and Therapeutic Approaches.

    PubMed

    Bano, Nusrat; Najam, Rahila; Qazi, Faaiza; Mateen, Ahmed

    2016-01-01

    Oxaliplatin, a third generation novel platinum compound is the most effective first line chemotherapeutic agent for colorectal cancer (CRC) in combination with 5FU and leucovorin. It is indicated for pancreatic, gastric and testicular cancers combined with bevacuzimab, capecitabine, irinotecan and other cytotoxic agents. However, moderate to severe hypersensitivity reactions (HSR) during or after oxaliplatin infusion usually require cessation of chemotherapy or substitution of the key therapeutic drug which largely interferes with improved patient prognosis. This mini- review showcases recent and accepted opinions/approaches in oxaliplatin induced HSR management. Physicians and oncologists have varying attitudes regarding the decision to rechallenge the patient after an HSR experience, efficacy of desensitization protocols, effectiveness and selection of drugs for premedication and possibilities of cross sensitivity to other platinum agents (e.g. carboplatin). A brief insight into underlying molecular mechanisms and clinical manifestations of oxaliplatin induced HSR is offered. We have also discussed the management of oxaliplatin induced HSR and risk stratification for a successful and complete chemotherapeutic plan. PMID:27221832

  10. 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.

  11. 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.

  12. 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.

  13. Reaction-induced strain localization: Torsion experiments on dolomite

    NASA Astrophysics Data System (ADS)

    Delle Piane, Claudio; Burlini, Luigi; Grobety, Bernard

    2007-04-01

    We investigated the mechanical behaviour and microstructural evolution of a dolomite marble from Mt. Frerone (Adamello, N-Italy) during decarbonation to calcite and periclase in torsion experiments. Tests were performed in a Paterson gas-medium apparatus on cylindrical samples of 10 mm diameter and 10 mm length. Experiments were conducted at 800 °C, 300 MPa confining pressure under both vented and non-vented conditions, up to a maximum bulk shear strain of about γ = 1.8, at different strain rates (3 × 10 - 5 s - 1 up to 3 × 10 - 4 s - 1 ). Under hydrostatic conditions the nominal equilibrium P(CO 2) should be around 100 MPa, but in the vented experiments the CO 2 was free to escape, causing the breakdown of dolomite. During the decomposition, deformation was systematically localized at the ends of the specimens, near the porous spacers into a fine-grained mixture of calcite and periclase. Due to the low permeability of the marble, pore fluid could not escape from the central part of the sample building up CO 2 pressure which suppressed the decarbonation reaction. The fluid pressure embrittled the material and caused the development of en-echelon tension fractures, inclined opposite to the sense of shear. We conclude that decarbonation produced a weak polyphase matrix composed of submicron sized reaction products. Such a small grain size induced strain localization which was probably promoted by a switch from grain-size insensitive to grain-size sensitive deformation mechanism.

  14. Electro-induced manipulations of liquid marbles for chemical reactions

    NASA Astrophysics Data System (ADS)

    Liu, Zhou; Fu, Xiangyu; Binks, Bernard P.; Shum, Ho Cheung; Microfluidics; Soft Matter Group in University of Hong Kong Team; Surfactant; Colloid Group at Hull Team

    2015-11-01

    Liquid marbles, liquid droplets coated by non-wetting particles, have been well demonstrated as a promising template for various droplet-based applications, in particular for chemical reactions. In these applications, controlled manipulations on liquid marbles, including coalescence and mixing, are highly demanded but yet rarely investigated. In this work, we study the coalescence and mixing of liquid marbles controlled by an electric field. We found that a sufficiently large applied voltage can cause the coalescence of two or multiple marbles arranged in a chain. This critical voltage, leading to the consequent coalescence, increases with the number of the liquid marbles. In addition, the imposed electric stress can induce convective liquid flow within the different liquid marbles, resulting in rapid and efficient mixing. The mixing efficiency can be conveniently tuned through varying the applied voltage. Our approach based on electro-assisted manipulations of liquids marbles represents a robust and feasible template for chemical or biomedical reactions involving multiple reagents and steps. We have demonstrated its potential by performing a chemiluminescence to detect the hydrogen peroxide encapsulated in liquid marbles.

  15. Modeling chemical reactions in laser-induced plasmas

    NASA Astrophysics Data System (ADS)

    Shabanov, S. V.; Gornushkin, I. B.

    2015-11-01

    Under the assumption of local thermal equilibrium, a numerical algorithm is proposed to find the equation of state for laser-induced plasmas (LIPs) in which chemical reactions are permitted in addition to ionization processes. The Coulomb interaction in plasma is accounted for by the Debye-Hückel method. The algorithm is used to calculate the equation of state for LIPs containing carbon, silicon, nitrogen, and argon. The equilibrium reaction constants are calculated using the latest experimental and ab initio data of spectroscopic constants for the molecules {N}_2, {C}_2, {Si}_2, {CN}, {SiN}, {SiC} and their ions. The algorithm is incorporated into a fluid dynamic numerical model based on the Navier-Stokes equations describing an expansion of LIP plumes into an ambient gas. The dynamics of LIP plumes obtained by the ablation of SiC, solid silicon, or solid carbon in an ambient gas containing {N}_2 and Ar is simulated to study formation of molecules and molecular ions.

  16. Photon- and meson-induced reactions on the nucleon

    NASA Astrophysics Data System (ADS)

    Feuster, T.; Mosel, U.

    1999-01-01

    Starting from a unitary effective Lagrangian model for the meson-nucleon scattering developed in T. Feuster and U. Mosel, Phys. Rev. 58, 457 (1998), we come to a unified description of both meson scattering and photon-induced reactions on the nucleon. To this end the photon is added perturbatively, yielding both Compton scattering and meson photoproduction amplitudes. In a simultaneous fit to all available data the parameters of the nucleon resonances are extracted. We find that a global fit to the data of the various channels involving the final states γN, πN, ππN, ηN, and KΛ is possible. Especially in eta photoproduction a readjustment of the masses and widths found in the fits to hadronic reactions alone is necessary to describe the data. Only for the D13(1520) do we find a possible disagreement for the helicity couplings extracted using the combined data set and pion photoproduction multipoles alone. The model dependence introduced by the restoration of gauge invariance is discussed and found to be significant mainly for resonances with small helicity couplings.

  17. Investigation of GEV Proton-Induced Spallation Reactions

    NASA Astrophysics Data System (ADS)

    Hilscher, D.; Herbach, C.-M.; Jahnke, U.; Tishchenko, V. G.; Galin, J.; Lott, B.; Letourneau, A.; Peghaire, A.; Filges, D.; Goldenbaum, F.; Nünighoff, K.; Schaal, H.; Sterzenbach, G.; Wohlmuther, M.; Pienkowski, L.; Schröder, W. U.; Toke, J.

    2004-09-01

    A reliable modeling of GeV proton-induced spallation reactions is indispensable for the design of the spallation module and the target station of future accelerator driven hybrid reactors (ADS) or spallation neutron sources (ESS), in particular, to provide precise predictions for the neutron production, the radiation damage of materials (window), and the production of radioactivity (3H, 7Be etc.) in the target medium. Detailed experimental nuclear data are needed for sensitive validations and improvements of the models, whose predictive power is strongly dependent on the correct physical description of the three main stages of a spallation reaction: (i) the Intra-Nuclear-Cascade (INC) with the fast heating of the target nucleus, (ii) the de-excitation due to pre-equilibrium emission including the possibility of multi-fragmentation, and (iii) the statistical decay of thermally excited nuclei by evaporation of light particles and fission in the case of heavy nuclei. Key experimental data for this endeavor are absolute production cross sections and energy spectra for neutrons and light charged-particles (LCPs), emission of composite particles prior and post to the attainment of an equilibrated system, distribution of excitation energies deposited in the nuclei after the INC, and fission probabilities. Systematic measurements of such data are furthermore needed over large ranges of target nuclei and incident proton energies. Such data has been measured with the NESSI detector. An overview of new and previous results will be given.

  18. Depth Profiling of N and C in Ion Implanted ZnO and Si Using Deuterium Induced Nuclear Reaction Analysis

    SciTech Connect

    Kennedy, John; Murmu, Peter; Markwitz, Andreas

    2008-11-03

    Nuclear Reaction Analysis (NRA) with deuteron ion beams has been used to probe for ion implanted nitrogen and carbon with high sensitivity in zinc oxide and silicon single crystals. The ion implanted N was measured using 1.4 MeV deuteron ion beams and was found to be in agreement with calculated values. The limit of detection for N in ZnO is 8x10{sup 14} ions cm{sup -2}. Raman measurements of the ion implanted samples showed three additional modes at 275, 504, and 644 cm{sup -1} compared to the un-implanted ZnO crystals. The NRA and Raman results provided information on the N concentration, depth distribution, and structural changes that occur in dependence on the nitrogen ion fluences. The deuterium induced {sup 12}C(d,p){sup 13}C reaction was used to measure the carbon impurity/dose in ion implanted silicon. It was found that the use of a large cold shield (liquid nitrogen trap) in the ion implanter chamber greatly reduces the amount of carbon impurity on the surface of ion implanted silicon. Various implantations with N{sub 2}, O{sub 2}, NO, NO{sub 2} and Pb ions were performed with and without cooling of the liquid nitrogen trap. Simultaneous detection of ppm-level concentrations of {sup 12}C, {sup 16}O and {sup 14}N enables highly sensitive measurement of impurities that may be incorporated during the fabrication process, transport of the samples and/or storage of the samples in air.

  19. Deformation effects on sub-barrier fusion cross sections in 16O+174,176Yb

    NASA Astrophysics Data System (ADS)

    Rajbongshi, Tapan; Kalita, K.; Nath, S.; Gehlot, J.; Banerjee, Tathagata; Mukul, Ish; Dubey, R.; Madhavan, N.; Lin, C. J.; Shamlath, A.; Laveen, P. V.; Shareef, M.; Kumar, Neeraj; Jisha, P.; Sharma, P.

    2016-05-01

    Background: Couplings with various reaction channels are known to enhance sub-barrier fusion cross sections by several orders in magnitude. However, a few open questions still remain. For example, the influence of higher order static deformations on sub-barrier fusion cross sections is yet to be comprehensively understood. Purpose: We study the role of hexadecapole nuclear deformation effect on sub-barrier fusion cross sections. Also, this work aims to extract hexadecapole deformation (β4) in nuclei in the lanthanide region. Method: The evaporation residue (ER) excitation functions for 16O+174,176Yb were measured at laboratory beam energies (Elab) in the range of 64.6-103.6 MeV. Measurements were carried out by employing the recoil mass spectrometer Heavy Ion Reaction Analyzer (HIRA) at IUAC, New Delhi. Fusion barrier distributions (BDs) were extracted from data. Results from the experiment were subjected to coupled-channels analysis, in which β4 was varied as a free parameter. Results: Experimental fusion cross sections at energies below the barrier expectedly showed strong enhancement compared to the predictions from the one-dimensional barrier penetration model. Data were satisfactorily reproduced after inclusion of negative β4 for both the targets in the coupled-channels calculation. Conclusions: The significant role of hexadecapole deformation was observed in the sub-barrier fusion of 16O+174,176Yb. The proposed value of β4 reproduced the measured fusion excitation function reasonably well. The BDs from these data were also extracted but no definitive conclusions could be drawn from them.

  20. Siderite breakdown and pressure induced Fe-C redox reactions

    NASA Astrophysics Data System (ADS)

    Lavina, Barbara; Dera, Przemyslaw; Kim, Eunja; Downs, Robert T.

    2010-05-01

    Siderite, FeCO3, was investigated at high pressure (up to ~ 40 GPa) and high temperature (up to about 2400K) using a laser heated diamond anvil cell. The structure of the sample was probed with a synchrotron monochromatic beam; powder, multigrain and single crystaldiffraction techniques were used according to changing size of the crystallites in the course of the experiment. At about 35 GPa we observed the breakdown of the carbonate into h-Fe3O4 (the orthorhombic high pressure phase of Fe3O4[1]) and undetected carbon phases. We suggest the breakdown was achieved through a redox reaction where the iron formal valence is increased at the expense of the carbon reduction. This observation is in agreement with results of shock experiments on siderite [2-4] in which however the presence of hematite in the starting material prevented to discriminate among possible reactions determining the synthesis of Fe3O4. Oxygen fugacity and the crystal chemistry of deep Earth mineral assemblages exert a major control on ionic speciation, therefore experimental confirmation are necessary to determine the actual redox equilibrium between iron and carbon in the mantle. Remarkably, perovskite strongly favor the partitioning of Fe3+ [5] and so it might favor the C reduction. If the pressure effect on Fe-C redox equilibrium found in this experiment is active in the deep Earth, the speciation of carbon would be strongly affected, in particular, the stability of carbonates and CO2 might be controlled by pressure induced reductions rather than by the stability of the pure phases. Carbon reduction at pressure might account for the greater subduction of carbon with respect to hydrogen [6]. On the other hand uplifting of reduced carbon assembly might release C-O fluids through reduction of Fe3+. Our results suggest that Fe-C redox reactions might have a crucial role on the carbon speciation which has a major importance on deep Earth processes. References [1] Haavik, et al. (2000) American

  1. Analyses of FT spectra of C2V ozone isotopologues in the 4500-5700 cm-1 region: 16O18O16O, 18O16O18O and 18O3

    NASA Astrophysics Data System (ADS)

    Barbe, A.; De Backer, M.-R.; Starikova, E.; Thomas, X.; Tyuterev, Vl. G.

    2014-12-01

    This work continues the systematic investigation of high resolution infrared spectra of 18O enriched ozone isotopologues in the 4500-6300 cm-1 spectral range. So far, the 16O18O16O and 18O16O18O spectra have been recorded and analysed using Fourier Transform Spectrometer (FTS) below 5000 cm-1 and using high sensitivity Cavity Ring-Down Spectroscopy above 6000 cm-1. In order to fill the gap between 5000 and 6000 cm-1, new infrared spectra were recorded with the Reims FTS. The analyses of the 2ν1+ν2+3ν3 band of 16O18O16O and of the 5ν3, ν1+2ν2+3ν3 and ν1+5ν3 bands of 18O16O18O are reported. New ν1+2ν2+3ν3 and ν1+5ν3 bands of 18O3 were also observed and analysed. Observed line positions were fitted using effective Hamiltonian models accounting for the dark state perturbations. The derived band centres and rotational constants are in a good agreement with new theoretical calculations from the molecular potential function.

  2. A HETEROGENEOUS CHEMICAL ORIGIN FOR THE {sup 16}O-ENRICHED AND {sup 16}O-DEPLETED RESERVOIRS OF THE EARLY SOLAR SYSTEM

    SciTech Connect

    Dominguez, Gerardo

    2010-04-10

    The oldest solids formed in the solar system, calcium-aluminum inclusions, are {sup 16}O-enriched compared to chondrules, asteroids, Earth, and Mars. Based on the preliminary measurements of the solar wind by Genesis, the Sun also appears to be {sup 16}O-enriched. This distribution of oxygen isotopes in the solar system cannot be reconciled via conventional mass-dependent isotopic fractionation processes and instead require the existence and/or production of distinct {sup 16}O-enriched and {sup 16}O-depleted reservoirs in the early solar system. The origin of these distinct reservoirs is unknown, although several mechanisms have been proposed to date including the following: (1) the injection of pure {sup 16}O by a supernova into the protoplanetary disk or parent molecular cloud, (2) self-shielding of CO in the parent molecular cloud or protoplanetary disk, (3) symmetry-dependent chemical fractionation processes in the protoplanetary disk, and (4) Galactic chemical evolution. While some of these proposals have been ruled out, the validity of others is still open. Here I propose that the {sup 16}O-enriched and {sup 16}O-depleted reservoirs present in the early solar system originated in the parent molecular cloud via the heterogeneous chemical processes that form H{sub 2}O, a significant oxygen reservoir, on the surface of interstellar (IS) dust grains in dense molecular clouds, the astrophysical setting where star formation is observed to occur. As a consequence, this model predicts that molecular cloud H{sub 2}O and possibly other IS solids inherited from the molecular cloud were depleted in {sup 16}O compared to the bulk gas-phase O present, thus providing distinct {sup 16}O reservoirs at the earliest stages of planetary formation.

  3. Will water act as a photocatalyst for cluster phase chemical reactions? Vibrational overtone-induced dehydration reaction of methanediol

    SciTech Connect

    Kramer, Zeb C.; Takahashi, Kaito; Skodje, Rex T.; Vaida, Veronica

    2012-04-28

    The possibility of water catalysis in the vibrational overtone-induced dehydration reaction of methanediol is investigated using ab initio dynamical simulations of small methanediol-water clusters. Quantum chemistry calculations employing clusters with one or two water molecules reveal that the barrier to dehydration is lowered by over 20 kcal/mol because of hydrogen-bonding at the transition state. Nevertheless, the simulations of the reaction dynamics following OH-stretch excitation show little catalytic effect of water and, in some cases, even show an anticatalytic effect. The quantum yield for the dehydration reaction exhibits a delayed threshold effect where reaction does not occur until the photon energy is far above the barrier energy. Unlike thermally induced reactions, it is argued that competition between reaction and the irreversible dissipation of photon energy may be expected to raise the dynamical threshold for the reaction above the transition state energy. It is concluded that quantum chemistry calculations showing barrier lowering are not sufficient to infer water catalysis in photochemical reactions, which instead require dynamical modeling.

  4. Epinephrine Treatment is Infrequent and Biphasic Reactions Are Rare in Food-Induced Reactions During Oral Food Challenges in Children

    PubMed Central

    Järvinen, Kirsi M.; Amalanayagam, Sujitha; Shreffler, Wayne G.; Noone, Sally; Sicherer, Scott H.; Sampson, Hugh A.; Nowak-Węgrzyn, Anna

    2009-01-01

    Background Data about epinephrine utilization and biphasic reactions in childhood food-induced anaphylaxis during oral food challenges are scarce. Objective To determine the prevalence and risk factors of reactions requiring epinephrine and the rate of biphasic reactions during oral food challenges (OFCs) in children. Methods Reaction details of positive OFCs in children between 1999 and 2007 were collected using a computerized database. Selection of patients for OFCs was generally predicated on ≤50% likelihood of a positive challenge and a low likelihood of a severe reaction based on the clinical history, specific IgE levels, and skin prick tests (SPTs). Results A total of 436 of 1273 OFCs resulted in a reaction (34%). Epinephrine was administered in 50 challenges (11% of positive challenges, 3.9% overall); for egg (n=15, 16% of positive OFCs to egg), milk (n=14, 12%), peanut (n=10, 26%), tree nuts (n=4, 33%), soy (n=3, 7%), wheat (n=3, 9%), and fish (n=1, 9%). Reactions requiring epinephrine occurred in older children (median 7.9 vs. 5.8 years, P<0.001), and were more often caused by peanuts (P=0.006) when compared to reactions not treated with epinephrine. There was no difference in the gender, prevalence of asthma, history of anaphylaxis, specific IgE level, SPTs, or amount of food administered. Two doses of epinephrine were required in 3/50 patients (6%) reacting to wheat, cow’s milk, and pistachio. There was one (2%) biphasic reaction. No reaction resulted in life-threatening respiratory or cardiovascular compromise. Conclusion Older age and reactions to peanuts were risk factors for anaphylaxis during oral food challenges. Reactions requiring multiple doses of epinephrine and biphasic reactions were infrequent. PMID:20004784

  5. [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.

  6. [Analyze causes of adverse reactions induced by traditional Chinese medicine injections from its quality standards].

    PubMed

    Cui, Hong-Yu; Liang, Ai-Hu

    2014-03-01

    Reviewing the literatures about adverse reactions induced by traditional Chinese medicine injections (TCMI) reported on CNKI from 1983 to 2013. Analyzing the causes of adverse reactions induced by TCMI from its quality standards. Provide ideas for improving security of TCMI and completing its quality standards. This review indicates that TCMI-induced adverse reactions have little relationship with the number of compositions, but have tight connection with chemical ingredients and solvents. Adverse reactions can be decreased by perfecting the quality standards of TCMI. PMID:25204194

  7. The A2Πi˜X2Σ+ interaction in CO +: Deperturbation analyses of B- A and A- X bands of 12C 16O +, 13C 16O + and 14C 16O +

    NASA Astrophysics Data System (ADS)

    Coxon, John A.; Kępa, Ryszard; Piotrowska, Izabela

    2010-08-01

    The 1-0, 6-0 and 6-1 bands of the A2Πi→X2Σ+ system of 13C 16O + and the 2-0 and 2-1 bands of the A2Πi→X2Σ+ system of 14C 16O + have been recorded at high resolution for the first time. The 0-2 and 5-0 bands of the A → X system of 12C 16O + have also been recorded at higher resolution than in previous work. The spectra were excited in an air-cooled hollow cathode discharge and photographed using a 2-m plane grating spectrograph. The spectral resolution and the Doppler-broadened line widths are both ˜0.12 cm -1, and the experimental measurement precision of resolved lines is ˜0.02 cm -1. The measured line positions, sometimes in combination with literature data on the B2Σ+→A2Πi transition, have been employed in deperturbation analyses of level crossings in the near-degenerate A(0)˜ X(10) and A(5)˜ X(14) interactions in 12C 16O +, the A(1)˜ X(11) and A(6)˜ X(15) interactions in 13C 16O +, and the A(2)˜ X(12) interaction in 14C 16O +. No radial dependence of the electronic perturbation matrix elements HSO( r) and HRE( r) could be detected over the narrow range of r-centroids (1.477-1.501 Å), and the mean values of these parameters are HSO = -49.06(15) cm -1 and HRE = 0.211(2). Using iteratively improved RKR potentials and FC-overlap integrals, the mean HSO and HRE were employed in least-squares analyses of A → X literature data involving A( υ) levels of the three isotopologues that are affected by interactions with one or two distant X( υ∗) levels. The fitted parameters of the A2Πi state ( B υ, A υ, A Dυ, p υ, q υ) exhibit υ-dependences that are much smoother than those employing perturbed parameters determined in previous investigations. In addition, a significant electronic isotope effect has been characterized. The separations Te( A)- Te( X) of the minima of the A and X states of 13C 16O + and 14C 16O + are less than that of 12C 16O + by 0.39 and 0.73 cm -1, respectively. Although Born-Oppenheimer breakdown of this magnitude is

  8. Polyethylene Glycol (PEG)-Induced Anaphylactic Reaction During Bowel Preparation

    PubMed Central

    2015-01-01

    Barium enema is used to screen patients with gastrointestinal bleeding who do not want to undergo colonoscopy. Polyethylene glycol (PEG) is usually the bowel preparation of choice. Few allergic reactions from this product have been reported; these include urticaria, angioedema, and anaphylaxis. Reactions are thought to result from a small amount of PEG crossing the intestinal mucosa, which, in some patients, is sufficient to provoke an anaphylactic reaction. PMID:26203443

  9. [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. PMID:23650772

  10. Fission following complete fusion for {sup 16}O + {sup 232}Th at 140 MeV

    SciTech Connect

    Frawley, A.D.

    1995-09-01

    Previously published results of coincidence measurements between incomplete fusion products and fission fragments from the reaction of 140 MeV {sup 16}O with {sup 232}Th have been used to determine the incomplete fusion contributions to the inclusive fission fragment angular distribution. The incomplete fusion contributions have been subtracted from the inclusive angular distribution, leaving the part due to complete fusion. Because the incomplete fusion processes account for 42% of the fission cross section, the maximum angular momentum contributing to complete fusion is reduced to approximately 55{h_bar}. The angular distribution for fission following complete fusion has been compared with calculations made with the saddle point transition state model and with Bond`s scission point model. When proper account is taken of the large reduction in nuclear temperature at the saddle point due to pre-fission neutron evaporation, the saddle point transition state model reproduces the data very well. Proper handling of the incomplete fusion contributions is found to greatly improve the agreement of Bond`s scission point model with the data for this reaction.

  11. Photo-induced isomerization and chemical reaction dynamics in superfluid helium droplets

    NASA Astrophysics Data System (ADS)

    Merritt, Jeremy; Douberly, Gary; Miller, Roger

    2008-03-01

    Near threshold photo-induced isomerization and photo-induced chemical reactions have long been sough after as sensitive probes of the underlying potential energy surface. One of the most important questions asked is how the initially bright quantum state couples to the reaction coordinate, and thus relates to energy transfer in general. Helium droplets have now allowed us to stabilize entrance channel clusters behind very small reaction barriers such that vibrational excitation may result in reaction. Through two examples, namely the isomerization of the 2 binary complexes of HF-HCN Douberly et al. PCCP 2005, 7,463, and the induced reaction of the gallium-HCN complex Merritt et al. JPCA 2007, DOI:10.1021/jp074981e we will show how the branching ratios for reaction and predissociation can determined and the influence of the superfluid He solvent.

  12. Assessment of nuclear-reaction codes for proton-induced reactions on light nuclei below 250 MeV

    NASA Astrophysics Data System (ADS)

    Braunn, Benjamin; Boudard, Alain; David, Jean-Christophe; Koning, Arjan J.; Leprince, Anne; Leray, Sylvie; Mancusi, Davide

    2015-07-01

    We assess the suitability of nuclear-reaction codes for the generation of accurate cross-section libraries targeted at the simulation of the transport of high-energy protons (up to 250 MeV) in the human body, or in any material containing light nuclides. To this end we present an extensive study of elastic, reaction and fragmentation cross sections for proton-induced reactions on several nuclides. We compare TALYS evaluations against experimental data and, wherever applicable, against the predictions of the INCL/ABLA07 nuclear-reaction model. The TALYS evaluations have been cast in the form of a new cross-section library, which also includes evaluated proton-proton cross sections based on the NN-OnLine tool.

  13. 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

  14. Studies of alpha-induced astrophysical reactions at CRIB

    NASA Astrophysics Data System (ADS)

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

    2010-08-01

    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, (α,p) reactions, and others were performed in recent years mainly for studying astrophysical reactions and exotic nuclear structure. Among them, the results on the 7Li+α resonance scatterings are presented.

  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. Levetiracetam Induced Drug Reaction with Eosinophilia and Systemic Symptom Syndrome

    PubMed Central

    Dar, Waseem Raja; Sofi, Najeebullah; Latief, Muzamil; Dar, Imtiyaz Ahmad; Kasana, Basharat Ahmad

    2016-01-01

    Drug reaction with eosinophilia and systemic symptom syndrome (DRESS) is a hypersensitivity drug reaction, most frequently associated with antiepileptic drugs, characterized by skin rash, fever, pharyngitis, lymphadenopathy, and visceral organ involvement, typically presenting within 8 weeks of initiation of therapy. Management involves prompt withdrawal of the offending drug and use of systemic corticosteroids. We here present a rare case of DRESS secondary to levetiracetam. Only few case reports of DRESS secondary to levetiracetam have been published so far. PMID:27057042

  17. Levetiracetam Induced Drug Reaction with Eosinophilia and Systemic Symptom Syndrome.

    PubMed

    Dar, Waseem Raja; Sofi, Najeebullah; Latief, Muzamil; Dar, Imtiyaz Ahmad; Kasana, Basharat Ahmad

    2016-01-01

    Drug reaction with eosinophilia and systemic symptom syndrome (DRESS) is a hypersensitivity drug reaction, most frequently associated with antiepileptic drugs, characterized by skin rash, fever, pharyngitis, lymphadenopathy, and visceral organ involvement, typically presenting within 8 weeks of initiation of therapy. Management involves prompt withdrawal of the offending drug and use of systemic corticosteroids. We here present a rare case of DRESS secondary to levetiracetam. Only few case reports of DRESS secondary to levetiracetam have been published so far. PMID:27057042

  18. Dark current induced in large CCD arrays by proton-induced elastic reactions and single to multiple-event spallation reactions

    SciTech Connect

    Chen, L.; McNulty, P.J.; Larson, S. . Dept. of Physics and Astronomy); Thompson, D.A.; Miller, T.L.; Lee, T. )

    1994-12-01

    Computer simulations of the non-ionizing energy loss deposited in sensitive volumes as a result of proton-induced spallation reactions agree with analytic models for large sensitive volumes exposed to high fluence. They predict unique features for small volumes and low-fluence exposures which are observed in exposures of large arrays of CCD pixels. Calculations of the number of spallation reactions per pixel correlate with the recently reported relative frequency of switching dark-current states.

  19. 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.

  20. Simulation and evaluation of nuclear reaction spectra

    NASA Astrophysics Data System (ADS)

    Vizkelethy, G.

    1990-01-01

    A RUMP-like-[1] computer code was written for PCs in order to simulate and evaluate nuclear reaction spectra. The code was written in Turbo Pascal. Any particle-target combination can be used; the stopping power calculation based on the ZBL algorithm [2] and the cross sections are taken from experimental data. The effects of straggling and geometrical spread are included in the simulation. Examples are given for the 16O(d,P) 17O, 18O(P,α) 15N, 16O( 3He,α) 15O and 16O(α,α) 16O reactions and for ERDA measurements.

  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. Hot fusion-evaporation cross sections of 44Ca-induced reactions with lanthanide targets

    NASA Astrophysics Data System (ADS)

    Werke, T. A.; Mayorov, D. A.; Alfonso, M. C.; Tereshatov, E. E.; Folden, C. M.

    2015-11-01

    Background: Previously reported cross sections of 45Sc-induced reactions with lanthanide targets are much smaller than 48Ca-induced reactions on the same targets. 44Ca is one proton removed from 45Sc and could be used to produce nuclei with a relative neutron content between those produced in the 45Sc- and 48Ca-induced reactions. Purpose: As part of a systematic investigation of fusion-evaporation reactions, cross sections of 44Ca-induced reactions on lanthanide targets were measured. These results are compared to available data for 48Ca- and 45Sc-induced fusion-evaporation cross sections on the same lanthanide targets. Collectively, these data provide insight into the importance of the survival against fission of excited compound nuclei produced near spherical shell closures. Methods: A beam of 6+Ca at an energy of ≈5 MeV /u was delivered by the K500 superconducting cyclotron at the Cyclotron Institute at Texas A&M University. The desired evaporation residues were selected by the Momentum Achromat Recoil Spectrometer and identified via their characteristic α -decay energies. Excitation functions for the 44Ca+158Gd ,159Tb, and 162Dy reactions were measured at five or more energies each. A theoretical model was employed to study the fusion-evaporation process. Results: The 44Ca-induced reactions have x n cross sections that are two orders of magnitude larger than 45Sc-induced reactions but two orders of magnitude smaller than 48Ca-induced reactions on the same targets. Proton emission competes effectively with neutron emission for the 44Ca+159Tb and 162Dy reactions. The maximum 4 n cross sections in the 44Ca+158Gd ,159Tb, and 162Dy reactions were 2100 ± 230 ,230 ± 20 , and 130 ±20 μ b , respectively. The 44Ca+158Gd and 159Tb cross sections are in good agreement with the respective cross bombardments of 48Ca+154Gd and 45Sc+158Gd once differences in capture cross sections and compound nucleus formation probabilities are corrected for. Conclusions: Excitation

  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. Neutron transfer reactions induced by Li8 on Be9

    NASA Astrophysics Data System (ADS)

    Guimarães, V.; Lichtenthäler, R.; Camargo, O.; Barioni, A.; Assunção, M.; Kolata, J. J.; Amro, H.; Becchetti, F. D.; Jiang, Hao; Aguilera, E. F.; Lizcano, D.; Martines-Quiroz, E.; Garcia, H.

    2007-05-01

    Angular distributions for the elastic scattering of Li8 on Be9 and the neutron transfer reactions Be9(Li8,Li7)Be10 and Be9(Li8,Li9)Be8 were measured with a 27 MeV Li8 radioactive nuclear beam. Spectr- oscopic factors for Li8 ⊗n= Li9 and Li7 ⊗n= Li8 bound systems were obtained from the comparison between the experimental differential cross section and finite-range distorted-wave Born approximation calculations with the code FRESCO. The spectroscopic factors obtained were compared to shell model calculations and to other experimental values from (d,p) reactions. Using the present values for the spectroscopic factor, cross sections for the direct neutron-capture reactions Li7(n,γ)Li8 and Li8(n,γ)Li9 were calculated in the framework of a potential model.

  5. Physiological environment induces quick response - slow exhaustion reactions.

    PubMed

    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 (d(s)), 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 d(s) 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

  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. A Theory of Laser Induced Nuclear Reaction in Single Atoms

    SciTech Connect

    Faisal, F. H. M.; Donner, C.

    2010-02-02

    An 'electron-bridge' mechanism of nuclear reaction in an atom or ion by ultra-intense laser fields is presented. A preliminary estimate of the intensity dependence of the rate of disintegration reaction of deuteron nucleus in deuterium atom is made for 800 nm laser fields. For intensities below 5x10{sup 21} W/cm{sup 2}, the rate of disintegration by the 'electron-bridge' mechanism is found to be small, but it rises sharply and becomes large already for {approx_equal}10{sup 22} W/cm{sup 2}.

  8. 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.

  9. Simulation of Reaction-Induced Phase Separation in Surface Alloy

    NASA Astrophysics Data System (ADS)

    Zvejnieks, G.; Tornau, E. E.

    2008-03-01

    Using kinetic Monte Carlo method we simulate the dynamics of biatomic Au0.3Ni0.7 surface alloy separation on Ni(111) due to Ni(CO)4 out-reaction. The experiment of Vestergaard et al. is modeled by counterbalancing dynamical processes and interactions between reactants. The simulations demonstrate step flow rate increase with CO coverage, cCO, in qualitative agreement with the experiment only for cCO ≲ 0.45 monolayer. Moreover, we demonstrate both CO influence on reaction process and Au domain formation.

  10. Barites - Anomalous xenon from spallation and neutron-induced reactions

    NASA Technical Reports Server (NTRS)

    Srinivasan, B.

    1976-01-01

    Sedimentary barites from South Africa and Western Australia (about 3 billion years old) contain spallogenic Xe isotopes produced by reactions of Ba with nuclear-active particles in cosmic rays. 'Surface residence time' of these samples was calculated from the observed concentrations of spallogenic Xe-126. Comparison of spallogenic ratios of Xe-131/Xe-126 in the two samples provides evidence for the reaction Ba-130(n, gamma) yields Xe-131, which is characterized by a large number of resonances for neutron absorption in the epithermal region. This observation lends additional support to the conclusions already reached regarding the origin of anomalous Xe-131 in lunar samples.

  11. Fusion probability for neutron-rich radioactive Sn induced reactions

    SciTech Connect

    Liang, J Felix; Gross, Carl J; Kohley, Zachary W; Shapira, Dan; Varner Jr, Robert L; Allmond, James M; Caraley, Anne L; Lagergren, Karin B; Mueller, Paul Edward

    2012-01-01

    Evaporation residue cross sections for $^{124,126,127,128}$Sn+$^{64}$Ni and $^{132}$Sn+$^{58}$Ni have been measured to study the effects of neutron excess in neutron-rich radioactive nuclei on fusion. For the reactions with $^{64}$Ni, the fusion probability does not decrease with increasing neutron excess in Sn, contrary to the result of the stable beam Sn+Zr measurement. A comparison of the reduced evaporation residue cross sections for $^{126}$Sn+$^{64}$Ni and $^{132}$Sn+$^{58}$Ni, which make the same compound nucleus, shows that the fusion probability is indistinguishable for reactions involving the same atomic elements but different isotope combinations.

  12. [IgE-induced anaphylactic reaction after eating lamb meat].

    PubMed

    Johansen, Kasper Lorenz; Rasmussen, Kirsten

    2014-08-25

    This article presents the case of a 54-year-old male, who was admitted to hospital after suffering a severe anaphylactic reaction after tasting a spoonful of chili con carne and four months later after eating lamb meat. Galactose-alpha-1,3-galactose allergy was suspected and the subsequent blood test showed highly elevated specific IgE levels. Delayed allergy to meat is a relatively new type of allergy and the delayed onset of allergic symptoms poses a diagnostic challenge to the physician. This type of allergy should be considered when there has been no obvious allergen exposition prior to the allergic reaction. PMID:25293709

  13. Rheological monitoring of phase separation induced by chemical reaction in thermoplastic-modified epoxy

    SciTech Connect

    Vinh-Tung, C.; Lachenal, G.; Chabert, B.

    1996-12-31

    The phase separation induced by chemical reaction in blends of tetraglycidyl-diaminodiphenylmethane epoxy resin with an aromatic diamine hardener and a thermoplastic was monitored. Rheological measurements and morphologies are described.

  14. 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.

  15. 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.

  16. Energies of molecular structures in 12C,16O,20Ne,24Mg, and 32S

    NASA Astrophysics Data System (ADS)

    Royer, G.; Ramasamy, G.; Eudes, P.

    2015-11-01

    The energies of the 12C,16O,20Ne,24Mg, and 32S 4 n nuclei have been determined within a generalized liquid drop model and assuming different planar and three-dimensional shapes of the α molecules: linear chain, triangle, square, tetrahedron, pentagon, trigonal bipyramid, square pyramid, hexagon, octahedron, octagon, and cube. The potential barriers governing the entrance and decay channels via α absorption or emission as well as more symmetric binary and ternary reactions have been compared. The rms radii of the linear chains differ from the experimental rms radii of the ground states. The binding energies of the three-dimensional shapes at the contact point are higher than the ones of the planar configurations. The α particle plus A-4 daughter configuration leads always to the lowest potential barrier. The binding energy can be reproduced within the sum of the binding energy of n α particles plus the number of bonds multiplied by 2.4 MeV or by the sum of the binding energies of one α particle and the daughter nucleus plus the Coulomb energy and the proximity energy.

  17. 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.

  18. 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.

  19. Multimodal Fission in Heavy-Ion Induced Reactions

    SciTech Connect

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

    2006-08-14

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

  20. 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. PMID:12009227

  1. 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.

  2. 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. PMID:20365620

  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. Kinetics Of Isomerisation Reaction Of Oriented Polyacetylene Induced By Laser

    SciTech Connect

    Mammeri, S.; Belloum, M.; Tabacik, V.

    2008-09-23

    The impact of a laser's photons ({lambda} = 514.5 nm) on the surface of polyacetylene films (PA), composed of macromolecules PAcis and PAtrans produces simultaneously thermal and Raman diffusion [1]. The thermal effect initializes the isomerization of macromolecules PAcis to PAtrans [2]; this reaction is exothermic. Samples are polyacetylene oriented films synthesized horizontally or vertically in cis configuration and are subject to different laser powers during intervals of time which vary between 20 s and 250 s. The power (P ({lambda}), mW) of the laser is equivalent to the temperature T, of isomerization [3]. Isotherms are constructed and are characterized by the laser power applied. We have established theoretical models calculations with the aim of determining the kinetic parameters of the reaction of isomerization: the activation energy (Ea), the frequency factor of Arrhenius (A), and the rate constant (k). We concluded that even in the field of seconds, the isomerization is a complex process different from a reaction of order: 1, 7/10, 2/3, 3/5, 1/2, 2/5 and 1/4. The order 2/3 being the most suitable. The study determined, among others, the rate constants k 2/3 (T)(of the order 2/3 of the isomerization reaction)= 0.003337244, 0.0052149, 0.0209636, 0.043727 s-1 respectively for Laser powers 30, 120, 200 and 300 mW; activation energy 17.7844 kcal/mol and a factor of collision 19.066816 10{sup 6} s{sup -1}. These results are found to be close to the experimental results studied.

  5. Shock induced reaction of Ni/Al nanopowder mixture.

    PubMed

    Meng, C M; Wei, J J; Chen, Q Y

    2012-11-01

    Nanopowder Ni/Al mixture (mixed in Al:Ni = 2:1 stoichiometry) was shock compressed by employing single and two-stage light gas gun. The particle size of Al and Ni are 100-200 nm and 50-70 nm respectively, morphologies of Al and Ni are sphere like either. Recovered product was characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD) analysis. According to the XRD spectrum, the mixed powder undergo complete reaction under shock compression, reaction product consist of Ni2Al3, NiAl and corundum structure Al2O3 compound. Grain size of Ni-Al compound is less than 100 nm. With the shock pressure increasing, the ratio of Ni2Al3 decreased obviously. The corundum crystal size is 400-500 nm according to the SEM observation. The results of shock recovery experiments and analysis show that the threshold pressure for reaction of nano size powder Ni/Al mixture is much less than that of micro size powder. PMID:23421276

  6. Pathogenic mechanisms underlying adverse reactions induced by intravenous administration of snake antivenoms.

    PubMed

    León, Guillermo; Herrera, María; Segura, Álvaro; Villalta, Mauren; Vargas, Mariángela; Gutiérrez, José María

    2013-12-15

    Snake antivenoms are formulations of immunoglobulins, or immunoglobulin fragments, purified from the plasma of animals immunized with snake venoms. Their therapeutic success lies in their ability to mitigate the progress of toxic effects induced by snake venom components, when administered intravenously. However, due to diverse factors, such as deficient manufacturing practices, physicochemical characteristics of formulations, or inherent properties of heterologous immunoglobulins, antivenoms can induce undesirable adverse reactions. Based on the time lapse between antivenom administration and the onset of clinical manifestations, the World Health Organization has classified these adverse reactions as: 1 - Early reactions, if they occur within the first hours after antivenom infusion, or 2 - late reactions, when occurring between 5 and 20 days after treatment. While all late reactions are mediated by IgM or IgG antibodies raised in the patient against antivenom proteins, and the consequent formation of immune complexes, several mechanisms may be responsible for the early reactions, such as pyrogenic reactions, IgE-mediated reactions, or non IgE-mediated reactions. This work reviews the hypotheses that have been proposed to explain the mechanisms involved in these adverse reactions to antivenoms. The understanding of these pathogenic mechanisms is necessary for the development of safer products and for the improvement of snakebite envenomation treatment. PMID:24055551

  7. 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.…

  8. Project ERIC - The search for environmental reactions induced by comets

    NASA Technical Reports Server (NTRS)

    Mendillo, Michael; Sigwarth, John B.; Craven, John D.; Frank, Louis A.; Holt, John

    1990-01-01

    A sounding rocket experiment was conducted to release molecules of H2O and CO2 into the daytime ionosphere within the simultaneous fields of view of the Millstone Hill radar and the Dynamics Explorer UV imager. Preliminary results confirm the creation of chemically-induced F-region plasma depletions and reduced UV intensities from the modified region.

  9. ({sup 16}O + {sup 232}Th) incomplete fusion followed by fission at 140 MeV

    SciTech Connect

    Gavathas, E.P.

    1993-12-31

    Cross sections for incomplete fusion followed by fission have been measured for the reaction ({sup 16}O + {sup 232}Th) at 140 MeV. In plane and out of plane measurements were made of cross sections for beamlike fragments in coincidence with fission fragments. The beamlike fragments were detected with the Florida State large acceptance Bragg curve spectrometer. The detector was position sensitive in the polar direction. The beamlike particles observed in coincidence with fission fragments were He, Li, Be, B, C, N and O. Fission fragments were detected by three surface barrier detectors using time of flight for particle identification. The reaction cross section due to incomplete fusion is 747 {+-} 112 mB, or 42% of the total fission cross section. The strongest incomplete fusion channels were the helium and carbon channels. The average transferred angular momentum for each incomplete fusion channel was calculated using the Q{sub opt} model of Wilczynski, and the angular correlation was calculated using the saddle point transition state model. The K distribution was determined from the Rotating Liquid Drop model. The theoretic angular distributions were fitted to the experimental angular distributions with the angular momentum J and the dealignment factor {alpha}{sub 0} as free parameters. The fitted parameter J was in excellent agreement with the Q{sub opt} model predictions. The conclusions of this study are that the incomplete fusion cross section is a large part of the total cross section, and that the saddle point transition state model adequately describes the observed angular correlations for fission following incomplete fusion.

  10. 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.

  11. [Adverse reaction induced by licorice preparations: clinical analysis of 93 cases].

    PubMed

    Mao, Min; Li, Wei; Wang, Wei; Wang, Shu-Xia; Lu, Jin; Chang, Zhang-Fu

    2013-11-01

    Licorice is a traditional Chinese medicine commonly used in clinic. The products,what contain licorice or licorice extract, has early been involved in the field of cosmetics except for the field of pharmaceuticals and food. Consequently, the reporting on adverse reactions induced by licorice preparations are more frequent. Based on the clinical data of licorice preparations adverse reactions, we described the characteristics of the licorice-related adverse reactions, and proposed specific measures to reduce the incidence of adverse reactions, provided a reference for the rational use of licorice preparations. PMID:24494570

  12. Evaluation of photon production data from neutron-induced reactions

    SciTech Connect

    Fu, C.Y.

    1980-01-01

    The evaluation methods and procedures used for generating the photon production data in the current Evaluated Nuclear Data File (ENDF/B, Version V) are reviewed. There are 42 materials in the General Purpose File of ENDF/B-V that contain data for prompt photon production. Almost all evaluations had substantial experimental data bases, but fewer than half of them employed any of the following evaluation methods. Only a few used theoretical techniques that are sophisticated enough to ensure internal consistency with other particle production data. Comments are made on four evaluation methods: the empirical formalism of Howerton et al., the Troubetzkoy model, the multiparticle Hauser-Feshbach/precompound model, and the Yost method. Critiques are also made on three procedures used for conserving photon energies in neutron capture reactions. The presence of photon production data in the file is useful for studying energy balance, since photon production generally accounts for a large portion of the reaction energy output. Problems found in energy balance checks are discussed. 9 figures, 1 table.

  13. 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

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

    PubMed

    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

  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. Kinetic studies of the infrared-induced reaction between atomic chlorine and solid parahydrogen

    NASA Astrophysics Data System (ADS)

    Raston, Paul L.; Kettwich, Sharon C.; Anderson, David T.

    2015-04-01

    We present Fourier-transform infrared (FTIR) spectroscopic studies of the IR-induced Cl + H2(v = 1) → HCl + H reaction in a parahydrogen (pH2) matrix aimed at distinguishing between two proposed reactions mechanisms; direct-IR and vibron-mediated. The Cl atom reactants are produced via 355 nm in situ photolysis of a Cl2 doped pH2 matrix. After photolysis is complete, a long-pass IR filter in the FTIR beam is removed and we measure the ensuing IR-induced reaction kinetics using rapid scan FTIR spectroscopy. We follow both the decay of the Cl atom reactant and growth of the HCl product using the Cl spin-orbit (SO) + Q1(0) and HCl R1(0) transitions, respectively. We show the IR-induced reaction mechanism depends on the spectral profile of the IR radiation; for IR spectral profiles that have significant IR intensities between 4000 and 5000 cm-1 we observe first-order kinetics that are assigned to a vibron-mediated mechanism and for spectral profiles that have significant IR intensities that include the Cl SO + Q1(0) transition near 5094 cm-1 we observe bi-exponential kinetics that are dominated by the direct-IR mechanism at early reaction times. We can distinguish between the two mechanisms using the observed kinetics. We investigate the reaction kinetics for different FTIR optical setups, for a range of sample conditions, and start and stop the IR-induced reaction to investigate the importance of secondary H atom reactions. We also study the IR-induced reaction in Br/Cl co-doped pH2 samples and show the presence of the Br atom quenches the vibron-mediated reaction kinetics presumably because the Br-atoms serve as efficient vibron traps. This paper indicates that in a highly enriched pH2 matrix the H atoms that are produced by the IR-induced Cl atom reaction likely do not play a significant role in the measured reaction kinetics which implies these secondary H atom reactions are highly selective.

  17. Nonsudden limits of heavy-ion induced knockout reactions.

    PubMed

    Flavigny, F; Obertelli, A; Bonaccorso, A; Grinyer, G F; Louchart, C; Nalpas, L; Signoracci, A

    2012-06-22

    We report on the single neutron and proton removal reactions from unstable nuclei with large asymmetry ΔS = S(n)-S(p) at incident energies below 80 MeV/nucleon. Strong nonsudden effects are observed in the case of deeply-bound-nucleon removal. The corresponding parallel momentum distributions exhibit an abrupt cutoff at high momentum that corresponds to an energy threshold occurring when the incident energy per particle is of comparable magnitude to the nucleon separation energy. A large low-momentum tail is related to both dissipative processes and the dynamics of the nucleon removal process. New limits for the applicability of the sudden and eikonal approximations in nucleon knockout are given. PMID:23004591

  18. 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.

  19. 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.

  20. Synthesis of Superheavy Nuclei in 48Ca-Induced Reactions

    NASA Astrophysics Data System (ADS)

    Oganessian, Y. T.; Utyonkov, V. K.; Lobanov, Y. V.; Abdullin, F. S.; Polyakov, A. N.; Shirokovsky, I. V.; Tsyganov, Y. S.; Gulbekian, G. G.; Bogomolov, S. L.; Gikal, B. N.; Mezentsev, A. N.; Iliev, S.; Subbotin, V. G.; Sukhov, A. M.; Voinov, A. A.; Buklanov, G. V.; Subotic, K.; Zagrebaev, V. I.; Itkis, M. G.; Moody, K. J.; Wild, J. F.; Stoyer, M. A.; Stoyer, N. J.; Shaughnessy, D. A.; Kenneally, J. M.; Patin, J. B.; Lougheed, R. W.

    This paper presents results of experiments aimed atproducing long-lived superheavy elements located near the spherical shells at Z≥ 114 and N≥ 172 in the reactions of neutron-rich isotopes 242,244Pu, 243Am, 245,248Cm and 249Cf with 48Ca projectiles. The decay properties of the synthesized nuclei are consistent with the consecutive α-decays originating in the decays of parent nuclides 286,287,288,289114, 287,288115, 290,291,293116 and 294118 produced in the 2n- to 5n-evaporation channels. The present observations can be considered to be experimental evidence of the existence of the ``island of stability'' of superheavy elements.

  1. Energy dependence of incomplete fusion processes in the {sup 16}O+{sup 181}Ta system: Measurement and analysis of forward-recoil-range distributions at E{sub lab}<=7 MeV/nucleon

    SciTech Connect

    Singh, Devendra P.; Unnati,; Yadav, Abhishek; Singh, B. P.; Prasad, R.; Singh, Pushpendra P.; Sharma, Manoj Kumar; Golda, K. S.; Kumar, Rakesh; Sinha, A. K.

    2010-05-15

    To study the energy dependence of incomplete fusion processes, the recoil range distributions for the reactions {sup 181}Ta({sup 16}O,xn), {sup 181}Ta({sup 16}O,pxn), {sup 181}Ta({sup 16}O,alphan), {sup 181}Ta({sup 16}O,alpha2n), {sup 181}Ta({sup 16}O,alpha3n), and {sup 181}Ta({sup 16}O,2alpha3n) have been measured at approx =81-, 90-, and 96 MeV beam energies. The disentanglement of the complete and incomplete fusion processes have been done in terms of full and partial linear momentum transfer from the projectile to the target nucleus. The measurements have been done using recoil catcher technique. The experimentally measured forward recoil range distributions have been interpreted in terms of breakup fusion model. Detailed analysis of the data indicates that incomplete fusion processes have significant contribution at energies as low as approx =5 MeV/nucleon and their contribution is found to increase with energy.

  2. Delayed gamma radiation from lightning induced nuclear reactions

    NASA Astrophysics Data System (ADS)

    Greenfield, M. B.; Sakuma, K.; Ikeda, Y.; Kubo, K.

    2004-03-01

    An increase in atmospheric gamma radiation observed with NaI and Ge detectors positioned about 15 m above ground was observed following natural lightning near Tokyo, Japan [1]. Background subtracted gamma ray rates GRR following numerous lightning strokes observed since 2001 persisted for a few hours and subsequently decayed with a half-life of about 50 minutes. Using a 3x3 Ge detector, with 2 KeV resolution, positioned about 2 m from one of the NaI detectors increases in GRR were observed minutes after the onset of lightning with a delayed 50 min exponential decay. Although most of the increase in activity occured at less than a few 100 KeV, on July 11, 2003 a 1267 +/-2 KeV line was observed. Although the statistics of this event were poor, the appearance of this line with an exponential decay of 50 min half-life suggests the possibility that it may be due to 39Cl (1267 MeV; half-life = 55.5 min) via the 40Ar(gamma,p)39Cl, 40Ar(p,2p)39Cl and/or 40Ar(n,d)39Cl reactions. Observations of > 10 MeV gamma rays observed in NaI detectors within 10s of meters from and coincident with rocket-triggered lightning at the International Center for Lightning Research and Testing suggest that charged particles accelerated in intense electric fields associated with lightning give rise to photons with sufficient energy to initiate nuclear reactions [2]. Further work to explain the cause of this anomalous activity is underway using natural and triggered lightning. 1. M. B. Greenfield et al., Journal of Applied Physics 93 no. 3 (2003) pp 1839-184. 2. J. R. Dwyer et al., Science 299, (2003), pp 694-697 and recent communications

  3. 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.

  4. Application of the Trojan Horse Method to study neutron induced reactions: the 17O(n, α)14C reaction

    NASA Astrophysics Data System (ADS)

    Gulino, M.; Spitaleri, C.; Tang, X. D.; Guardo, G. L.; Lamia, L.; Cherubini, S.; Bucher, B.; Burjan, V.; 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.; O'Brien, S.; Pizzone, R. G.; Rapisarda, G. G.; Roberson, D.; Sergi, M. L.; Tan, W.; Thompson, I. J.; Wiescher, M.

    2014-03-01

    The reaction 17O(n, α)14C was studied using virtual neutrons coming from the quasi-free deuteron break-up in the three body reaction 17O+d → α+14C+p. This technique, called virtual neutron method, extends the Trojan Horse method to neutron-induced reactions allowing to study the reaction cross section avoiding the suppression effects coming from the penetrability of the centrifugal barrier. For incident neutron energies from thermal up to a few hundred keV, direct experiments have shown the population of two out of three expected excited states at energies 8213 keV and 8282 keV and the influence of the sub-threshold level at 8038 keV. In the present experiment the 18O excited state at E* = 8.125 MeV, missing in the direct measurement, is observed. The angular distributions of the populated resonances have been measured for the first time. The results unambiguously indicate the ability of the method to overcome the centrifugal barrier suppression effect and to pick out the contribution of the bare nuclear interaction.

  5. 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.

  6. 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.

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

    SciTech Connect

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

    2013-04-19

    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 {sup 195}Au 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.

  8. Complexity of lectin-mediated reactions in bacteria-induced histamine release.

    PubMed

    Jensen, C; Stahl Skov, P; Norn, S; Espersen, F; Bøg-Hansen, T C; Lihme, A

    1984-08-01

    We have earlier suggested that bacteria-induced histamine release is caused by different mechanisms, including allergic and non-immunological mechanisms, and that the latter probably depends on lectin-mediated reactions. Two possibilities of lectin-mediated reactions were examined in this study, bacterial surface lectins bind to sugars on the basophil cell membrane leading to histamine release, and the reverse reaction where bacterial aminosugars react with lectins on the basophil cell surface. In the bacterial histamine release caused by the Staph. aureus strain Wood 46 it was possible to demonstrate a reverse reaction, but not a bacterial lectin-mediated reaction. The reaction seems to be complex, as lower concentrations of sugars might potentiate the release of histamine by binding to the target cell or bacteria, while the release is inhibited by higher concentrations. PMID:6208803

  9. 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.

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

    NASA Astrophysics Data System (ADS)

    Yamashita, Teruo; Schubnel, Alexandre

    2016-05-01

    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.

  11. Nivolumab-Induced Sarcoid-Like Granulomatous Reaction in a Patient With Advanced Melanoma.

    PubMed

    Danlos, François-Xavier; Pagès, Cécile; Baroudjian, Barouyr; Vercellino, Laetitia; Battistella, Maxime; Mimoun, Maurice; Jebali, Majdi; Bagot, Martine; Tazi, Abdellatif; Lebbé, Céleste

    2016-05-01

    To our knowledge, we report the first case of sarcoid-like granulomatous reaction induced by nivolumab, a fully human IgG4 anti-programmed death 1 (PD-1) immune checkpoint inhibitor antibody. A 57-year-old man was treated with nivolumab 3 mg/kg for 2 weeks for a desmoplastic melanoma stage III American Joint Commission on Cancer, with no BRAF, NRAS, and cKit mutations. At 10 months, although melanoma complete response was achieved, he developed sarcoid-like granulomatous reaction in the mediastinal lymph node and skin, which resumed after nivolumab arrest. Melanoma did not relapse after 12 months of follow-up. Considering the recently demonstrated role of activated PD-1/PDL-1 axis in sarcoidosis, granulomatous reaction in the patient seems to be a paradoxical reaction, but similar observations have been reported with ipilimumab, another immune checkpoint inhibitor. Sarcoid-like granulomatous reaction during immunotherapy treatment could be a manifestation of cell-mediated immunity induced by these drugs. Impact of granulomatous reaction induced by immune checkpoint inhibitor on melanoma progression is not known and requires further study. Melanoma patients treated by immunotherapy (anti-cytotoxic T-lymphocyte-associated protein-4/anti-PD-1) should be considered for developing sarcoid-like granulomatous reaction that must not be confused with tumor progression. PMID:27157227

  12. 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.

  13. Air-broadened line parameters with temperature dependence for 12C16O, 13C16O, and 12C18O at 2.3 μm

    NASA Astrophysics Data System (ADS)

    Smith, M. H.; Malathy Devi, V.; Benner, D.; Mantz, A. W.; Sung, K.; Brown, L. R.

    2012-12-01

    To improve the spectroscopic database for remote sensing of tropospheric CO, we have recorded more than 50 high resolution (0.005 cm-1) spectra of CO and two of its isotopologues (13CO and C18O) at temperatures between 150 and 298 K using a coolable absorption cell in the sample compartment of the Bruker IFS 125HR Fourier transform spectrometer at Jet Propulsion Laboratory. Air-broadened spectra at total pressures up to 700 Torr were recorded for all three isotopologues, and self-broadened CO spectra were also recorded. Line parameters were determined by broad-band constrained multispectrum least-squares fitting of 16 or more spectra simultaneously. Parameters determined in the fits included Lorentz half-width coefficients, their temperature dependence exponents; pressure-induced line shift coefficients, their temperature dependences; and the off-diagonal relaxation matrix elements that characterize line mixing. Speed dependence parameters were also included to minimize the fit residuals. The individual line positions and intensities were constrained to their theoretical relationships in order to obtain the rovibrational (G, B, D, and H) and band intensity parameters, including Herman-Wallis coefficients, as has been done for CO2 previously. The air-broadening results for the 13C16O and 12C18O 2-0 bands are compared with each other and with those for the corresponding 12C16O band.

  14. Synthesis of Superheavy Nuclei in 48CA-INDUCED Reactions

    NASA Astrophysics Data System (ADS)

    Oganessian, Yu. Ts.; Utyonkov, V. K.; Lobanov, Yu. V.; Abdullin, F. Sh.; Polyakov, A. N.; Sagaidak, R. N.; Shirokovsky, I. V.; Tsyganov, Yu. S.; Voinov, A. A.; Gulbekian, G. G.; Bogomolov, S. L.; Gikal, B. N.; Mezentsev, A. N.; Iliev, S.; Subbotin, V. G.; Sukhov, A. M.; Subotic, K.; Zagrebaev, V. I.; Vostokin, G. K.; Itkis, M. G.; Moody, K. J.; Patin, J. B.; Shaughnessy, D. A.; Stoyer, M. A.; Stoyer, N. J.; Wilk, P. A.; Kenneally, J. M.; Landrum, J. H.; Wild, J. F.; Lougheed, R. W.

    2008-11-01

    Thirty-four new nuclides with Z = 104-116, 118 and N = 161-177 have been synthesized in the complete-fusion reactions of 238U, 237Np, 242,244Pu, 243Am, 245,248Cm, and 249Cf targets with 48Ca beams. The masses of evaporation residues were identified through measurements of the excitation functions of the xn-evaporation channels and from cross bombardments. The decay properties of the new nuclei agree with those of previously known heavy nuclei and with predictions from different theoretical models. A discussion of self-consistent interpretations of all observed decay chains originating from the parent isotopes 282,283112, 282113, 286-289114, 287,288115, 290-293116, and 294118 is presented. Decay energies and lifetimes of the neutron-rich superheavy nuclei as well as their production cross sections indicate a considerable increase in the stability of nuclei with an increasing number of neutrons, which agrees with the predictions of theoretical models concerning the decisive dependence of the structure and radioactive properties of superheavy elements on their proximity to the nuclear shells with N = 184 and Z = 114.

  15. Facility for neutron induced few body reactions at Bochum University

    NASA Astrophysics Data System (ADS)

    Bannach, B.; Bodek, K.; Börker, G.; Kamke, D.; Krug, J.; Lekkas, P.; Lübcke, W.; Stephan, M.

    1987-02-01

    A facility is described which is designed for the measurement of neutron induced three-body breakup. It has been used for the breakup of deuterium and of the nucleus 9Be. Neutrons are produced by a pulsed beam of deuterons from the Bochum 4MV Dynamitron-Tandem accelerator by bombarding a thick tritium-titanium target or a deuterium gas target. The outgoing beam is collimated by a 4π shielding to a solid angle of about 1 msr. In most cases, a liquid scintillator (NE232 or a mixture of NE232/NE213) serves as a target for the neutron beam. Scattered neutrons are detected by NE213-detectors of different sizes. For testing purposes the differential elastic n-d cross section and simultaneously the response of NE232 have been measured at 22.4 and 7.9 MeV.

  16. 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

    2015-01-01

    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. PMID:25515673

  17. Cross Section Calculations of Deuteron-induced Reactions Using the Extended CCONE Code

    NASA Astrophysics Data System (ADS)

    Nakayama, S.; Araki, S.; Watanabe, Y.; Iwamoto, O.; Ye, T.; Ogata, K.

    2014-04-01

    We have extended the CCONE code to make it possible to calculate cross sections for deuteron-induced reactions. Elastic breakup and stripping reactions to continuum are calculated using another codes based on the Continuum-Discretized Coupled-Channels theory (CDCC) and the Glauber model, respectively, and the calculated results are inputted to the CCONE code as direct reaction components. Statistical decay from compound nuclei formed by nucleon stripping and deuteron absorption is calculated with the exciton and Hauser-Feshbach models implemented in the original CCONE code. The extended CCONE code is applied to analyses of deuteron-induced reactions on 27Al and 58Ni. CDCC calculations for deuteron elastic scattering show good agreement with the experimental data at incident energies of several tens of MeV. The calculated double-differential (d,xp) cross sections reproduce the measured ones at forward angles for incident energies of 56 and 100 MeV fairly well.

  18. {sup 18}O/{sup 16}O and {sup 17}O/{sup 16}O ratios in atmospheric nitrous oxide: A mass-independent anomaly

    SciTech Connect

    Cliff, S.S.; Thiemens, M.H.

    1997-12-05

    Measurements of the oxygen isotope ratios ({sup 18}O/{sup 16}O and {sup 17}O/{sup 16}O) in atmospheric nitrous oxide (N{sub 2}O) from La Jolla, Pasadena, and the White Mountain Research Station (elevation, 3801 meters) in California and the White Sands Missile Range in New Mexico show that N{sub 2}O has a mass-independent composition. These data suggest the presence of a previously undefined atmospheric process. The La Jolla samples can be explained by a mixing between an atmospherically derived source of mass-independent N{sub 2}O and biologically derived mass-dependent N{sub 2}O. Possible origins of the mass-independent anomally in N{sub 2}O are discussed. 32 refs., 2 figs.

  19. 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.

  20. Radiation-induced reactions of COH 2 gas mixtures over various solid catalysts

    NASA Astrophysics Data System (ADS)

    Nagai, S.; Arai, H.; Hatada, M.

    Studies have been carried out of radiation-induced reactions of COH 2 gas mixtures in the presence of various solid catalysts in order to find possibilities of synthesizing organic raw materials from COH 2 by radiation for the future. The solid catalysts studied include Fischer-Tropsch catalyst (FeCu supported by diatomaceous earth), titania(TiO 2), and silica gel. Analysis of the reaction products over Fischer-Tropsch catalyst or semiconductors such as TiO 2 and ZnOCr 2O 3 reveals that these solid catalysts do not sensitize the radiation chemical reaction of COH 2 but show the secondary effects on the reaction so as to induce the hydrogenation of olefins produced by the catalytic reaction and of aldehydes produced in gas phase by radiation. On the other hand, silica gel and other insulators such as alumina have been found to exhibit high catalytic activity in the formation of hydrocarbons from COH 2 under electron beam irradiation at 300°C. It has been shown experimentally that secondary reactions between H 2 and carbonaceous solid produced from CO make a substantial contribution to the formation of hydrocarbons from COH 2 over silica gel. In an attempt to find the role of silica gel in the reaction to produce hydrocarbons, radiation-induced reactions have been studied of H 2 with the carbonaceous solid that had been produced by irradiation of CO in the absence of solid catalyst, over TiO 2, or over silica gel. The results indicate that silica gel not only enhances the yields of CO 2 and carbonaceous solid from CO but also promotes hydrogenation reactions of the carbonaceous solid under electron beam irradiation.

  1. Integrative analysis of proteomics and metabolomics of anaphylactoid reaction induced by Xuesaitong injection.

    PubMed

    Xu, Yubin; Dou, Deqiang; Ran, Xiaoku; Liu, Chunyan; Chen, Jing

    2015-10-16

    Injection with natural compounds is an important method in the application of natural medicine, but its adverse drug reactions (ADRs) occur frequently, particularly the anaphylactoid reaction, which accounts for more than 77% of all reactions and has become a serious threat to public health. Here, the Xuesaitong injection (XSTI) was employed as an example to elucidate its anaphylactoid mechanism and look for potential biomarkers to assay the anaphylactoid reaction of herbal medicine injection by proteomics and metabolomics. These results disclosed that 13 differential proteins and 28 metabolites, which were further approved using the ELISA method and reference standards, respectively, were suggested as potential biomarkers to examine the anaphylactoid mechanism. The up-regulated expression of Gpx1, Sc5b9, C4d and down-regulated expression of F12, Kng1, C2 and C6 revealed that the XSTI-induced anaphylactoid reaction occurs via direct stimulation, complement and the kallikrein-kinin pathway. In addition, substances that induce an anaphylactoid effect include histamine, LTB4, uric acid and other drugs, which have been confirmed to be involved in arginine and proline metabolism, histidine metabolism, arachidonic acid metabolism purine metabolism and the TCA cycle. Furthermore, separation experiments have indicated that 10-kDa molecules of XSTI are the main allergenic factor inducing an anaphylactoid reaction. PMID:26372445

  2. 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. PMID:27590551

  3. 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

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

    PubMed

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

    2010-08-01

    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 on

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Shock-induced reaction behavior of Ti-Si and Ti-B powder mixtures

    SciTech Connect

    Royal, T.E.; Thadhani, N.N.; Graham, R.A.

    1995-12-31

    Mechanistic processes controlling the shock-induced chemical reaction behavior of highly reactive Ti-Si and Ti-B powder-mixtures were investigated. Recovery experiments were performed, using Sandia Bear fixtures, to determine the reaction initiation thresholds for the respective systems, and to produce compacts of unreacted states to characterize the shock-compressed configuration of reactants at conditions below the reaction threshold. X-ray diffraction line broadening and scanning electron microscopy analysis were used to determine the response of individual reactants during shock-compression. It was observed that the deformation and/or fracture response of reactants during shock-compression influences the threshold conditions for, reaction initiation and the overall reaction propensity.

  10. Au25 Clusters as Electron-Transfer Catalysts Induced the Intramolecular Cascade Reaction of 2-nitrobenzonitrile

    PubMed Central

    Chong, Hanbao; Li, Peng; Wang, Shuxin; Fu, Fangyu; Xiang, Ji; Zhu, Manzhou; Li, Yadong

    2013-01-01

    Design of atomically precise metal nanocluster catalysts is of great importance in understanding the essence of the catalytic reactions at the atomic level. Here, for the first time, Au25z nanoslusters were employed as electron transfer catalysts to induce an intramolecular cascade reaction at ambient conditions and gave rise to high conversion (87%) and selectivity (96%). Electron spin-resonance spectra indeed confirmed the consecutive electron transfer process and the formation of N radical. UV-vis absorption spectra also verified Au25z was intact after the catalytic circle. Our research may open up wide opportunities for extensive organic reactions catalyzed by Au25z. PMID:24225495

  11. 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

  12. 4. 4-. mu. m cascade /sup 13/C /sup 16/O/sub 2/ laser

    SciTech Connect

    Johnson, R.P.; Cornelison, D.; Buzcek, C.J.

    1984-01-15

    An in-cavity hot /sup 13/C /sup 16/O/sub 2/ cell is used to obtain a 4.4-..mu..m lasing from a cascade process in a sealed off /sup 13/C /sup 16/O/sub 2/ laser. The 4.4-..mu..m laser is tunable and operates on the P branch (near 4.44 ..mu..m) and the R branch (near 4.39 ..mu..m) of the ((10/sup 0/1)/sub I/--(10/sup 0/0)/sub I/) band of /sup 13/C /sup 16/O/sub 2/. The laser is mechanically Q switched producing peak powers in excess of 10 W with repetition rates greater than 500 Hz.

  13. Analysis of the response of silicon detectors to α particles and 16O ions

    NASA Astrophysics Data System (ADS)

    Kirsebom, O. S.; Fynbo, H. O. U.; Riisager, K.; Raabe, R.; Roger, T.

    2014-09-01

    We clarify basic concepts concerning the response of silicon detectors to ionizing radiation, focusing on light ions with energies ranging from a few hundred keV to a few MeV. Through reanalysis of existing experimental data, we quantify the difference in the response of silicon detectors to α particles and 16O ions, and we determine the correction that must be made before an energy calibration obtained with α particles can be applied to the measurement of 16O ions. Finally, we show that an apparent disagreement among three recent measurements of the decay spectrum of 8B can be explained by a failure to correctly take into account the different response of silicon detectors to α particles and 16O ions.

  14. 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.

  15. 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/.

  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. 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.

  18. Elastic {sup 16}O{sup 16}O scattering at E({sup 16}O) = 350 MeV and new method for a model-independent determination of the scattering matrix

    SciTech Connect

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

    2007-06-15

    A new approach that can be used to extract the scattering matrix S(l) as a complex-valued function of the orbital angular momentum l directly from experimental data on elastic nucleus-nucleus scattering at intermediate energies without resort to additional model assumptions is developed on the basis of the evolutionary algorithm. Owing to the fact that the behavior of the derivatives of S(l) is automatically monitored within this approach, the scattering matrix obtained for {sup 16}O{sup 16}O interaction at an energy of 350 MeV is determined by its absolute value and the nuclear phase shift, which are smooth monotonic functions of the orbital angular momentum. Moreover, the result involves no distortions, the form of the quantum deflection function being typical of the nuclear-rainbow pattern. It is shown that the ultimate form of S(l) is independent of input representations of the scattering matrix, which were usually taken on the basis of various phenomenological models.

  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. Reactions Induced by Real Photons for Nuclear Structure and Nuclear Astrophysics

    NASA Astrophysics Data System (ADS)

    Enders, J.

    This contribution presents examples for recent experimental studies with real photons. Topics include the electric dipole response below the particle separation energy (pygmy resonance), the magnetic scissors mode in deformed nu, an analysis of low-lying electric quadrupole strength and astrophysical applications. Results of reactions induced by real photons are compared to those obtained from virtual photons (electron scattering, Coulomb excitation).

  1. 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.

  2. UV-Induced Tetrazole-Thiol Reaction for Polymer Conjugation and Surface Functionalization.

    PubMed

    Feng, Wenqian; Li, Linxian; Yang, Chengwu; Welle, Alexander; Trapp, Oliver; Levkin, Pavel A

    2015-07-20

    A UV-induced 1,3-dipolar nucleophilic addition of tetrazoles to thiols is described. Under UV irradiation the reaction proceeds rapidly at room temperature, with high yields, without a catalyst, and in both polar protic and aprotic solvents, including water. This UV-induced tetrazole-thiol reaction was successfully applied for the synthesis of small molecules, protein modification, and rapid and facile polymer-polymer conjugation. The reaction has also been demonstrated for the formation of micropatterns by site-selective surface functionalization. Superhydrophobic-hydrophilic micropatterns were successfully created by sequential modifications of a tetrazole-modified porous polymer surface with hydrophobic and hydrophilic thiols. A biotin-functionalized surface could be fabricated in aqueous solutions under long-wavelength UV irradiation. PMID:26059870

  3. Eosinophilic follicular reaction induced by Demodex folliculorum mite: a different disease from eosinophilic folliculitis.

    PubMed

    Sabater-Marco, V; Escutia-Muñoz, B; Botella-Estrada, R

    2015-06-01

    Eosinophilic folliculitis (EF) is an idiopathic dermatitis included in the spectrum of eosinophilic pustular follicular reactions. Demodex folliculorum has been implicated as contributing to the pathogenesis of human immunodeficiency virus-associated EF, but it has not been described outside this context. We present an immunocompetent 65-year-old white man with a 5-year history of recurrent pruritic erythematous and oedematous lesions on his face, neck and scalp. Histopathologically, an eosinophilic microabcess with Demodex folliculorum mite within a pilosebaceous follicle was seen, and considered the causal agent. There were also accumulations of eosinophil granules on collagen bundles, and flame figure formations in the dermis. We believe that 'eosinophilic follicular reaction' is an appropriate term to describe this case of EF induced by D. folliculorum and thus distinguish it from the idiopathic form of EF. Moreover, this case suggests that D. folliculorum can sometimes induce an eosinophilic immune reaction. PMID:25623943

  4. Neutron-induced fission cross sections of short-lived actinides with the surrogate reaction method.

    SciTech Connect

    Kessedijian, G.; Jurado, B.; Aiche, M.; Barreau, G.; Bidaud, A.; Czajkowski, S.; Dassie, D.; Haas, B.; Mathieu, L.; Audouin, L.; Capellan, N.; Tassan-Got, L.; Wilson, J. N.; Berthoumieux, E.; Gunsing, F.; Theisen, Ch.; Serot, O.; Bauge, E.; Ahmad, I.; Greene, J. P.; Janssens, R. V. F.

    2010-09-13

    Neutron-induced fission cross sections for {sup 242,243}Cm and {sup 241}Am have been obtained with the surrogate reaction method. Recent results for the neutron-induced cross section of {sup 243}Cm are questioned by the present data. For the first time, the {sup 242}Cm cross section has been determined up to the onset of second-chance fission. The good agreement at the lowest excitation energies between the present results and the existing neutron-induced data indicates that the distributions in spin and parity of states populated with both techniques are similar.

  5. Patch-test-induced "flare-up" reactions to neomycin at prior biopsy sites.

    PubMed

    Jacob, Sharon E; Barland, Chantal; ElSaie, Mohamed L

    2008-01-01

    "Recall dermatitis" classically refers to the uncommon phenomenon of chemotherapy-induced reactivation of skin damage originally induced by radiotherapy months or years earlier. We compare this condition to ectopic flare-up reactions presenting as dermatitis at existing or previous sites by an inducing agent. Enhanced sensitization of an existent allergen by patch testing is rarely described. We describe a case of a 61-year-old man's developing localized allergic contact dermatitis at previous neomycin-treated sites following the diagnosis of neomycin sensitivity on patch testing, which we attribute to a "flare-up" phenomenon. PMID:19134429

  6. CO2 pressure broadening and shift coefficients for the 2-0 band of 12C16O

    NASA Astrophysics Data System (ADS)

    Hashemi, R.; Predoi-Cross, A.; Dudaryonok, A. S.; Lavrentieva, N. N.; Vandaele, A. C.; Vander Auwera, J.

    2016-08-01

    Fourier transform absorption spectra of the 2-0 band of 12C16O mixed with CO2 have been recorded at total pressures from 156 to 1212 hPa and at 4 different temperatures between 240 K and 283 K. CO2 pressure-induced line broadening and line shift coefficients, and the temperature dependence of the former have been measured including line mixing using a multi-spectrum non-linear least squares fitting technique. Different line shape models have been considered to take into account the Dicke narrowing or speed dependence effects. Measured line-shape parameters were compared with theoretical values, calculated for individual temperatures using a semi-empirical method and the Exponential Power Gap (EPG) law.

  7. Fluctuation Induced Structure in Chemical Reaction with Small Number of Molecules

    NASA Astrophysics Data System (ADS)

    Suzuki, Yasuhiro

    We investigate the behaviors of chemical reactions of the Lotka-Volterra model with small number of molecules; hence the occurrence of random fluctuations modifies the deterministic behavior and the law of mass action is replaced by a stochastic model. We model it by using Abstract Rewriting System on Multisets, ARMS; ARMS is a stochastic method of simulating chemical reactions and it is based on the reaction rate equation. We confirmed that the magnitude of fluctuations on periodicity of oscillations becomes large, as the number of involved molecules is getting smaller; and these fluctuations induce another structure, which have not observed in the reactions with large number of molecules. We show that the underling mechanism through investigating the coarse grained phase space of ARMS.

  8. 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.

  9. 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.

  10. Direct and compound reactions induced by unstable helium beams near the Coulomb barrier

    NASA Astrophysics Data System (ADS)

    Navin, A.; Tripathi, V.; Blumenfeld, Y.; Nanal, V.; Simenel, C.; Casandjian, J. M.; de France, G.; Raabe, R.; Bazin, D.; Chatterjee, A.; Dasgupta, M.; Kailas, S.; Lemmon, R. C.; Mahata, K.; Pillay, R. G.; Pollacco, E. C.; Ramachandran, K.; Rejmund, M.; Shrivastava, A.; Sida, J. L.; Tryggestad, E.

    2004-10-01

    Reactions induced by radioactive 6,8 He beams from the SPIRAL facility were studied on 63,65 Cu and 188,190,192 Os targets and compared to reactions with the stable 4He projectiles from the Mumbai Pelletron. Partial residue cross sections for fusion and neutron transfer obtained from the measured intensities of characteristic in-beam γ rays for the 6He + 63,65 Cu systems are presented. Coincidence measurements of heavy reaction products, identified by their characteristic γ rays, with projectilelike charged particles, provide direct evidence for a large transfer cross section with Borromean nuclei 6He at 19.5 and 30 MeV and 8He at 27 MeV. Reaction cross sections were also obtained from measured elastic angular distributions for 6,8 He +Cu systems. Cross sections for fusion and direct reactions with 4,6 He beams on heavier targets of 188,192 Os at 30 MeV are also presented. The present work underlines the need to distinguish between various reaction mechanisms leading to the same products before drawing conclusions about the effect of weak binding on the fusion process. The feasibility of extracting small cross sections from inclusive in-beam γ -ray measurements for reaction studies near the Coulomb barrier with low intensity isotope separation on-line beams is highlighted.

  11. Direct and compound reactions induced by unstable helium beams near the Coulomb barrier

    SciTech Connect

    Navin, A.; Tripathi, V.; Chatterjee, A.; Kailas, S.; Mahata, K.; Ramachandran, K.; Shrivastava, A.; Blumenfeld, Y.; Tryggestad, E.; Nanal, V.; Pillay, R.G.; Simenel, C.; Casandjian, J.M.; France, G. de; Rejmund, M.; Raabe, R.; Pollacco, E.C.; Sida, J.L.; Dasgupta, M.

    2004-10-01

    Reactions induced by radioactive {sup 6,8}He beams from the SPIRAL facility were studied on {sup 63,65}Cu and {sup 188,190,192}Os targets and compared to reactions with the stable {sup 4}He projectiles from the Mumbai Pelletron. Partial residue cross sections for fusion and neutron transfer obtained from the measured intensities of characteristic in-beam {gamma} rays for the {sup 6}He+{sup 63,65}Cu systems are presented. Coincidence measurements of heavy reaction products, identified by their characteristic {gamma} rays, with projectilelike charged particles, provide direct evidence for a large transfer cross section with Borromean nuclei {sup 6}He at 19.5 and 30 MeV and {sup 8}He at 27 MeV. Reaction cross sections were also obtained from measured elastic angular distributions for {sup 6,8}He+Cu systems. Cross sections for fusion and direct reactions with {sup 4,6}He beams on heavier targets of {sup 188,192}Os at 30 MeV are also presented. The present work underlines the need to distinguish between various reaction mechanisms leading to the same products before drawing conclusions about the effect of weak binding on the fusion process. The feasibility of extracting small cross sections from inclusive in-beam {gamma}-ray measurements for reaction studies near the Coulomb barrier with low intensity isotope separation on-line beams is highlighted.

  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. Effects of salbutamol and enantiomers on allergen-induced asthmatic reactions and airway hyperreactivity.

    PubMed

    Westerhof, F J; Zuidhof, A B; Kok, L; Meurs, H; Zaagsma, J

    2005-05-01

    Salbutamol consists of a racemic mixture of R- and S-salbutamol. R-salbutamol (levalbuterol) is the active bronchodilating enantiomer, whereas S-salbutamol is thought to be pharmacologically inactive or to exert adverse effects. This study evaluated the bronchoprotective effects of inhalation of therapeutically relevant doses of the racemate and individual enantiomers in guinea pigs. It was found that basal airway reactivity to histamine was similarly reduced 30 min after inhalation of equivalent doses of RS- and R-salbutamol; this protective effect disappeared within 3 h. Inhalation of RS- and R-salbutamol 30 min before and 5.5 h after allergen challenge suppressed allergen-induced airway hyperreactivity to histamine after the early and late asthmatic reaction, completely inhibiting the early asthmatic reaction and tending to reduce the development of the late asthmatic reaction. At 5 h after allergen challenge, the inhibition of airway hyperreactivity was more pronounced in animals treated with R-salbutamol compared to racemate-treated animals. Both basal airway reactivity and allergen-induced hyperreactivity were not affected by S-salbutamol. Inflammatory cell infiltration was not affected by the racemate or the individual enantiomers. In conclusion, inhalation of therapeutically relevant doses of R- and RS-salbutamol effectively suppress allergen-induced airway reactivity after the early and late asthmatic reactions, the R-enantiomer being slightly more potent with respect to early airway reactivity than the racemate. No adverse effects were observed for the S-enantiomer. PMID:15863644

  14. Determination of Global Reaction Rate During Laser-Induced Decomposition at Static High Pressures

    NASA Astrophysics Data System (ADS)

    Russell, Thomas. P.; Pangilinan, Gerardo I.

    1998-03-01

    The laser induced decomposition of hexahydro-1,3,5-trinitro-1,3,5 triazine (C_3H_6N_6O_6, RDX), trinitro azetidine (C_3H_4N_3O_6, TNAZ) and ammonium perchlorate (NH_4ClO_4, AP) at static high pressure in the range of 0.6 - 2.0 GPa is presented. The samples are loaded in a gem anvil cell and the reaction is induced with a single laser pulse (514 nm, 6 μs duration, 3-22 J/cm^2). The dynamic chemical processes are probed using time resolved uv-Vis absorption spectroscopy, during and up to 20 μs after the laser pulse. In all three materials, decomposition is characterized by a time-dependent increase in absorbance from 300-500 nm. This absorption change is directly proportional to the mole fraction of reaction and provides a measurement of the global reaction rate. The reaction rate is determined to be dependent on the sample, the initial pressure, and the laser fluence. The chemical decomposition is modeled using a three term reaction rate equation encompassing initiation, growth, and coalescence. A description of the differences in the decomposition kinetics for each material will be provided. Finally, the implications of these measurements to models of macroscopic energy release rates will be addressed.

  15. 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.

  16. Pharmacoepidemiological characterization of drug-induced adverse reaction clusters towards understanding of their mechanisms.

    PubMed

    Mizutani, Sayaka; Noro, Yousuke; Kotera, Masaaki; Goto, Susumu

    2014-06-01

    A big challenge in pharmacology is the understanding of the underlying mechanisms that cause drug-induced adverse reactions (ADRs), which are in some cases similar to each other regardless of different drug indications, and are in other cases different regardless of same drug indications. The FDA Adverse Event Reporting System (FAERS) provides a valuable resource for pharmacoepidemiology, the study of the uses and the effects of drugs in large human population. However, FAERS is a spontaneous reporting system that inevitably contains noise that deviates the application of conventional clustering approaches. By performing a biclustering analysis on the FAERS data we identified 163 biclusters of drug-induced adverse reactions, counting for 691 ADRs and 240 drugs in total, where the number of ADR occurrences are consistently high across the associated drugs. Medically similar ADRs are derived from several distinct indications for use in the majority (145/163=88%) of the biclusters, which enabled us to interpret the underlying mechanisms that lead to similar ADRs. Furthermore, we compared the biclusters that contain same drugs but different ADRs, finding the cases where the populations of the patients were different in terms of age, sex, and body weight. We applied a biclustering approach to catalogue the relationship between drugs and adverse reactions from a large FAERS data set, and demonstrated a systematic way to uncover the cases different drug administrations resulted in similar adverse reactions, and the same drug can cause different reactions dependent on the patients' conditions. PMID:24534381

  17. 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.

  18. 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

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

    SciTech Connect

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

    2007-11-14

    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

  20. The formation and decay of superheavy nuclei produced in 48Ca-induced reactions

    NASA Astrophysics Data System (ADS)

    Kumar, Sushil; Balasubramaniam, M.; Gupta, Raj K.; Münzenberg, G.; Scheid, W.

    2003-04-01

    The formation of superheavy nuclei in 48Ca+232Th, 238U, 242,244Pu and 248Cm reactions and their subsequent decay are studied within the quantum mechanical fragmentation theory (QMFT) and the QMFT-based preformed cluster decay model (PCM) of Gupta and collaborators. According to QMFT, all these 48Ca-induced reactions are cold fusion reactions with relative excitation energies larger than those for the Pb-induced cold fusion reactions and smaller than those for the lighter beam, i.e. Mg, Si or S-induced hot fusion reactions. The same reactions were first suggested by Gupta et al in 1977 on the basis of QMFT, and this study re-establishes the same result. In fact, for such heavy isotopes of Z = 110 to 116, 50Ca is shown to be a better beam for cold fusion, but 50Ca is a radioactive nucleus. The alpha-decay half-lives of these nuclei after 3n and/or 4n evaporations, i.e. of the evaporation residues of these compound systems, calculated on PCM compare reasonably well with the experiments published by the Dubna group and another recent calculation. As expected for such rare decays, PCM calculations show that the alpha-preformation factors are small, ~10-8 to 10-10. The possible competition of alpha-decays with heavy cluster emissions from these superheavy nuclei is also probed from the point of view of searching for new nuclear structure information and possible future experiments with such exotic nuclei. The decay half-lives for some clusters are in fact shown to be lower than the limits of experiments for nuclei with enough available atoms.

  1. 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.

  2. Fractionation of Oxygen Isotopes by Thermal Ionization Mass Spectrometry Inferred from Simultaneous Measurement of (17)O/(16)O and (18)O/(16)O Ratios and Implications for the (182)Hf-(182)W Systematics.

    PubMed

    Trinquier, Anne

    2016-06-01

    Accurate (182)Hf-(182)W chronology of early planetary differentiation relies on highly precise and accurate tungsten isotope measurements. WO3(-) analysis by negative thermal ionization mass spectrometry requires W(17)O(16)O2(-), W(17)O2(16)O(-), W(18)O(16)O2(-), W(17)O3(-), W(17)O(18)O(16)O(-), and W(18)O2(16)O(-) isotopologue interference corrections on W(16)O3(-) species ( Harper et al. Geochim. Cosmochim. Acta 1996 , 60 , 1131 ; Quitté et al. Geostandard. Newslett. 2002 , 26 , 149 ; Trinquier et al. Anal. Chem. 2016 , 88 , 1542 ; Touboul et al. Nature 2015 , 520 , 530 ; Touboul et al. Int. J. Mass Spectrom. 2012 , 309 , 109 ). In addition, low ion beam intensity counting statistics combined with Faraday cup detection noise limit the precision on the determination of (18)O/(16)O and (17)O/(16)O relative abundances. Mass dependent variability of (18)O/(16)O over the course of an analysis and between different analyses calls for oxide interference correction on a per integration basis, based on the in-run monitoring of the (18)O/(16)O ratio ( Harper et al. Geochim. Cosmochim. Acta 1996 , 60 , 1131 ; Quitté et al. Geostandard. Newslett. 2002 , 26 , 149 ; Trinquier et al. Anal. Chem. 2016 , 88 , 1542 ). Yet, the (17)O/(16)O variation is normally not being monitored and, instead, inferred from the measured (18)O/(16)O variation, assuming a δ(17)O-δ(18)O Terrestrial Fractionation Line ( Trinquier et al. Anal. Chem. 2016 , 88 , 1542 ). The purpose of the present study is to verify the validity of this assumption. Using high resistivity amplifiers, (238)U(17)O2 and (238)U(18)O2 ion beams down to 1.6 fA have been monitored simultaneously with (235,238)U(16)O2 species in a uranium certified reference material. This leads to a characterization of O isotope fractionation by thermal ionization mass spectrometry in variable loading and running conditions (additive-to-sample ratio, PO2 pressure, presence of ionized metal and oxide species). Proper determination of O

  3. 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.

  4. 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. PMID:24201982

  5. Delta excitations in heavy nuclei induced by (3He,t) and (p,n) reactions

    NASA Astrophysics Data System (ADS)

    Esbensen, H.; Lee, T.-S. H.

    1985-12-01

    Delta excitations in heavy nuclei, induced by charge exchange reactions, are studied using the surface response model. The residual pion-exchange interaction and the self-energy of the delta in a nuclear medium is included in the random-phase-approximation response. The peak position observed in (3He,t) reactions can be explained by the self-energy of the delta extracted from pion-nucleus scattering, and the magnitude of the cross section is consistent with Glauber theory. The comparison to (p,n) data is reasonable; contributions from neutron decay of the delta, which are left out in the calculations, constitute a substantial experimental background.

  6. Experimental investigation and theoretical calculation for 3He induced nuclear reactions on vanadium

    NASA Astrophysics Data System (ADS)

    Ali, B. M.; Al-Abyad, M.; Seddik, U.; El-Kameesy, S. U.; Ditrói, F.; Takács, S.; Tárkányi, F.

    2016-04-01

    Using stacked-foil activation technique and gamma-ray spectrometry, excitation functions for 3He induced nuclear reactions on natV were measured. Cross-sections for natV(3He, xn)52m,gMn and natV(3He, pxn)51Cr nuclear reactions were measured up to 27 MeV utilizing the MGC-20E cyclotron of ATOMKI. The measurements establish for the first time consistent excitation curves. Comparisons with results for values derived from different theoretical codes were included. Integral yield were calculated.

  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. [Material for evaluation of notoginseng total saponin preparation induced pseudoanaphylactoid reactions].

    PubMed

    Yu, Ting-ting; Li, Jie; Zhao, Jia-wei; Zhang, Ya-xin; Li, Dan-dan; Liang, Ai-hua; Liu, Guan-ping; Gao, Shan; Gao, Yue

    2015-07-01

    The experiment is designed to explore pathological festures and material basis of pseadoanaphylactoid reaction induced by notoginseng total saponin preparation. Mouse pseadoanaphylactoid reaction was used, 50 ICR mice were randomly assigned to control group, positive medicine group, notoginseng total saponin preparation low-dose group, notoginseng total saponin preparation middle-dose group, notoginseng total saponin preparation high-dose group on average. They are treated by intravenous injection of test substance solutions containing 0.4% Evans blue (EB). 30 min later, scores of ear blue staining and quantitation of ear EB exudation were recorded. Another two experiment were repeated in the same way excluding EB, just to. detect the related cytokines in serum using ELISA. We found that the scores of pseudoanaphylactoid reaction in notoginseng total saponin preparation injection middle-dose group and high-dose group was evidently higher than that in control group, suggesting that notoginseng total saponin preparation injection may be can lead to pseadoanaphylactoid reaction. HE staining showed that pseadoanaphylactoid reaction induced by notoginseng total saponin preparation injection is related to inflammation. Histamine, VEGF and TNF-α levels in notoginseng total saponin preparation middle-dose group and high-dose group significantly increased (P < 0.05, P < 0.01) than control group and showed a dose-dependent manner as well as consistent with the degree of ear blue dye. While IL-6 and IL-10 content did not increase significantly in notoginseng total saponin preparation low-dose group and middle-dose group, but they significantly higher than control group (P < 0.05, P < 0.01) when it increased to quadrupe clinical concentrations, eight times of the clinical dose. So pseadoanaphylactoid reaction caused by notoginseng total saponin preparation may be related to histamine, VEGF, TNF-α, and it is possible that IL-6 and IL-10 can play a role when

  9. 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.

  10. Dynamics of the induced acrosome reaction in boar sperm evaluated by flow cytometry.

    PubMed

    Birck, Anders; Labouriau, Rodrigo; Christensen, Preben

    2009-10-01

    The present study investigated the dynamics of the in vitro induced acrosome reaction (AR) in boar sperm in response to medium composition, incubation time and ionophore concentration. The AR is a prerequisite for normal sperm fertilizing capability and can be studied in vitro following induction by various agents. The ability of a sperm population to undergo the AR in vivo is expected to influence male fertilizing potential, and attempts to relate the in vitro induced AR to fertility has been reported. However, to relate the induced AR to fertility one should be aware of the dynamics of the in vitro induced AR. A detailed description of the dynamics of sperm viability and acrosomal status of boar sperm following in vitro induction of the AR has to our knowledge not previously been conducted. In the present study, a triple color flow cytometric detection technique was used, which gave simultaneous information on sperm viability and acrosomal status. The ionophore induced AR was dependent on extracellular Ca(2+), but could be easily induced in boar sperm without capacitation. Capacitation-associated plasma membrane phospholipid scrambling was assessed and a medium specific ability to induce these membrane changes was observed. Both sperm viability and the induced AR were significantly affected by sperm capacitation, incubation time and ionophore concentration. The results lead to suggestions for an optimized AR induction protocol that takes both sperm viability and the effectiveness of AR induction into consideration. PMID:19084358

  11. Low-background spectrometer for the study of fast neutron-induced (n,α) reactions

    NASA Astrophysics Data System (ADS)

    Khriachkov, V. A.; Ketlerov, V. V.; Mitrofanov, V. F.; Semenova, N. N.

    2000-04-01

    An α-particle spectrometer based on an ionization chamber with Frisch grid and a waveform digitizer has been developed for studies of fast neutron-induced (n,α) reactions. The information on the energy of the α-particle and its emission angle can be obtained from the amplitude and rise time of the digitized anode signal. For a situation where both the solid target on the cathode of the ionization chamber and the working gas are the α-particle sources, a new method for the suppression of the neutron-induced background is proposed. The background due to gaseous α-particles was reduced by a factor of 30.

  12. Pre-irradiation-induced graft reaction of maleic anhydride onto polypropylene

    NASA Astrophysics Data System (ADS)

    Tan, X. M.; Xu, Y. S.; Wang, C. L.

    2006-09-01

    The radiation induced graft polymerization is a well-known method to obtain new materials. Until recently, only conventional radiation sources, such as Co-60 and electron beams, were used. Moreover, part of the damage induced in polymers by heavy ions can produce active sites (peroxides and hydroperoxides) that are useful to initiate grafting reactions. Maleic anhydride (MAH) was grafted onto polypropylene (PP) wax with a number-average molecular weight (Mn) of 8000 by gamma pre-irradiation technique. Effects of total dose, monomer concentration, reaction time, and temperature on percentage of grafting are studied in detail. It is shown that the optimum conditions for grafting are temperature of 70 degrees C and total dose of 14.4 kGy. PP-g-MAH is characterized by infrared spectrum. Differential scanning calorimetry shows that the compatibility of PP-g-MAH is better than that of PP.

  13. Chemical activity induces dynamical force with global structure in a reaction-diffusion-convection system.

    PubMed

    Mahara, Hitoshi; Okada, Koichi; Nomura, Atsushi; Miike, Hidetoshi; Sakurai, Tatsunari

    2009-07-01

    We found a rotating global structure induced by the dynamical force of local chemical activity in a thin solution layer of excitable Belousov-Zhabotinsky reaction coupled with diffusion. The surface flow and deformation associated with chemical spiral waves (wavelength about 1 mm) represents a global unidirectional structure and a global tilt in the entire Petri dish (100 mm in diameter), respectively. For these observations, we scanned the condition of hierarchal pattern selection. From this result, the bromomalonic acid has an important role to induce the rotating global structure. An interaction between a reaction-diffusion process and a surface-tension-driven effect leads to such hierarchal pattern with different scales. PMID:19658764

  14. Role of ν-induced reactions on lead and iron in neutrino detectors

    NASA Astrophysics Data System (ADS)

    Kolbe, E.; Langanke, K.

    2001-02-01

    We have calculated cross sections and branching ratios for neutrino-induced reactions on 208Pb and 56Fe for various supernova and accelerator-relevant neutrino spectra. This was motivated by the facts that lead and iron will be used on the one hand as target materials in future neutrino detectors and, on the other hand, have been and are still used as shielding materials in accelerator-based experiments. In particular we study the inclusive 56Fe(νe,e-)56Co and 208Pb(νe,e-)208Bi cross sections and calculate the neutron energy spectra following the decay of the daughter nuclei. These reactions give a potential background signal in the KARMEN and LSND experiment and are discussed as a detection scheme for supernova neutrinos in the proposed OMNIS and LAND detectors. We also study the neutron emission following the neutrino-induced neutral-current excitation of 56Fe and 208Pb.

  15. Neutron Induced Capture Reaction Studies in the Resonance Region at GELINA

    SciTech Connect

    Schillebeeckx, Peter; Borella, A.; Kopecky, S.; Mihailescu, L. C.; Siegler, P.; Sirakov, I.; Massimi, C.; Moxon, M.; Ware, T.

    2009-01-28

    The neutron time-of-flight facility GELINA installed at the IRMM Geel (B) has been designed to study neutron-induced reactions in the resonance region. It is a multi-user facility, providing a pulsed white neutron source, with a neutron energy range between 10 meV and 20 MeV and a time resolution of 1 ns. The research program concentrates on cross section data needs for nuclear energy applications. In this paper efforts to improve the quality of cross section data for neutron induced capture reactions in the resolved and unresolved resonance region are presented together with examples of cross section data to support the development of advanced reactor concepts and to optimize the use of present nuclear power plants.

  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. Macromolecular crowding conditions enhance glycation and oxidation of whey proteins in ultrasound-induced Maillard reaction.

    PubMed

    Perusko, Marija; Al-Hanish, Ayah; Cirkovic Velickovic, Tanja; Stanic-Vucinic, Dragana

    2015-06-15

    High intensity ultrasound (HIUS) can promote Maillard reaction (MR). Macromolecular crowding conditions accelerate reactions and stabilise protein structure. The aim of this study was to investigate if combined application of ultrasound and macromolecular crowding can improve efficiency of MR. The presence of crowding agent (polyethylene glycol) significantly increased ultrasound-induced whey protein (WP) glycation by arabinose. An increase in glycation efficiency results only in slight change of WP structure. Macromolecular crowding intensifies oxidative modifications of WP, as well as formation of amyloid-like structures by enhancement of MR. Solubility at different pH, thermal stability and antioxidative capacity of glycated WP were increased, especially in the presence of crowding agent, compared to sonicated nonglycated proteins. The application of HIUS under crowding conditions can be a new approach for enhancement of reactions in general, enabling short processing time and mild conditions, while preserving protein structure and minimising protein aggregation. PMID:25660883

  18. Electrical Detection of Fast Reaction Kinetics in Nanochannels with an Induced Flow

    PubMed Central

    Schoch, Reto B.; Cheow, Lih Feng; Han, Jongyoon

    2008-01-01

    Nanofluidic channels can be used to enhance surface binding reactions, since the target molecules are closely confined to the surfaces that are coated with specific binding partners. Moreover, diffusion-limited binding can be significantly enhanced if the molecules are steered into the nanochannels via either pressure-driven or electrokinetic flow. By monitoring the nanochannel impedance, which is sensitive to surface binding, low analyte concentrations have been detected electrically in nanofluidic channels within response times of 1–2 hours. This represents a ~54 fold reduction in the response time using convective flow compared to diffusion-limited binding. At high flow velocities the presented method of reaction kinetics enhancement is potentially limited by force-induced dissociations of the receptor-ligand bonds. Optimization of this scheme could be useful for label-free, electrical detection of biomolecule binding reactions within nanochannels on a chip. PMID:17997589

  19. Synthesis and characterization of ZnS nanowires by AOT micelle-template inducing reaction

    SciTech Connect

    Lv Ruitao; Cao Chuanbao; Zhu Hesun

    2004-08-03

    ZnS nanowires, with diameters around 30 nm and lengths up to 2.5 {mu}m, had been successfully synthesized from solutions containing an anionic surfactant, sodium bis(2-ethylhexyl)sulfosuccinate (AOT). Powder X-ray diffraction (XRD) pattern, energy-dispersive X-ray spectroscopy (EDS) and selected-area electron diffraction (SAED) pattern indicated that the product was pure polycrystalline cubic-phase {beta}-ZnS. The morphology and size of the as-synthesized product were determined by the transmission electron microscopy (TEM). The effects of some of the key reaction parameters (such as the ratio of surfactant to water, the reactant concentration and reaction temperature, etc.) had been explored in this paper. A growth mechanism of ZnS nanowires by micelle-template inducing reaction was also proposed.

  20. FIGARO: a New Facility for Studying Neutron-Induced Reactions that Produce Gamma Rays

    NASA Astrophysics Data System (ADS)

    Zanini, L.; Haight, R. C.; Devlin, M.; Aprahamian, A.

    2000-04-01

    FIGARO (Fast neutron-Induced GAmma-Ray Observer) was established in 1999 at LANSCE/WNR. This new capability is intended to extend our research into nuclear reactions and nuclear structure using gamma rays as the principal probe. The detector will consist of an array of germanium and NE-213 neutron detectors, operating in coincidence, placed at a distance of about 20 m from the neutron source. The scientific goals of FIGARO include: investigation of nuclear level densities using gamma-ray transitions as an indicator of angular momentum populated in the reaction; investigations of pre-equilibrium reactions; and study of cross sections and neutron emission spectra in (n,n') excitations. A first measurement, with the detection of only gamma-rays, has been performed with a ^59Co sample. By comparison with existing data(T. E. Slusarchyk, ORNL/TM-11404(1989)) we can assess the performance of the detector. Results will be discussed.

  1. 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.

  2. Peripheral interactions in the collision of [sup 16]O+[sup 238]U at 110. 4 MeV bombarding energy

    SciTech Connect

    Pagano, A.; Aiello, S.; De Filippo, E.; Lanzano, G.; Lo Nigro, S.; Milone, C.; Blancato, G.; Di Marco, G. ); Mermaz, M.C. )

    1993-03-01

    Inclusive and semiexclusive elemental production cross sections of projectilelike fragments emerging in the collision [sup 16]O+[sup 238]U at 110.4 MeV have been investigated. Energy spectra and angular distributions of projectile residues with charge from [ital Z]=3 to [ital Z]=8 have been measured. It has been found that, as expected, the dominant reaction mechanism in the peripheral collisions is a mass transfer from projectile to target mainly dominated by a transfer of an [alpha] particle. The in-plane coincidences between projectilelike and fission fragments suggest that 14% of the total fission cross section is associated with the fission of a targetlike nucleus.

  3. 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.

  4. 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.

  5. HLA-B*1502 and carbamazepine-induced severe cutaneous adverse drug reactions in Vietnamese

    PubMed Central

    Chu, Hieu Chi; Nguyen, Doan Van; Phan, Minh Hong; Craig, Timothy; Baumgart, Karl; van Nunen, Sheryl

    2015-01-01

    Background In Vietnam, we observed a high incidence of carbamazepine (CBZ)-induced severe cutaneous adverse drug reactions (SCARs)-Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN), and drug-induced hypersensitivity rash with eosinophilia and systemic symptoms (DRESS). In other Asian countries, HLA-B*1502 is an established risk factor for SCARs. Objective The aim of our study was to determine the frequency of HLA-B*1502 in SCARs patients at a large University Medical Center in Hanoi, Vietnam. Methods Thirty-eight cases of SCARs caused by CBZ and 25 patients with epilepsy tolerating CBZ were enrolled in a case-controlled study. Clinical manifestations and laboratory findings were recorded for each subject. Genomic DNA was isolated using the QIAamp DNA purification system. The combination of polymerase chain reaction and sequence specific oligonucleotide probes with the Luminex 100×MAP flow cytometry dual laser system was then used to quantitate fluorescently labelled oligonucleotides attached to colour-coded microbeads. Results Cases comprised 20 SJS (52.6%), 7 TEN (18.4%), 8 overlap syndrome (21.1%), and 3 DRESS patients (7.9%). A strong association between HLA B*1502 and bullous skin reactions such as SJS/TEN and overlap was confirmed with an odds ratio (OR) of 33.78 (95% confidence interval [CI], 7.55-151.03), p < 0.0001, Sensitivity 91.4%, Specificity 76.0%, positive predictive value 84.2%, and negative predictive value 86.4%. We did not, however, observe any correlation between the presence of this allele and CBZ-induced nonbullous skin reactions (DRESS) (OR, 6.33; 95% CI, 0.48-82.74; p = 0.1592). Conclusion Our results indicate the presence of HLA-B*1502 in Vietnamese is a pharmacogenetic risk factor for developing CBZ-induced SJS/TEN. PMID:25938071

  6. Cutaneous adverse drug reaction type erythema multiforme major induced by eslicarbazepine

    PubMed Central

    Massot, Andreu; Gimenez-Arnau, Ana

    2014-01-01

    Severe skin reactions occur less frequently with eslicarbazepine (ESL) than with the other aromatic anticonvulsants. We report the first case of cutaneous adverse drug reaction (CADR) to ESL and co-sensitization between ESL and betalactams. A 41-year-old white woman developed focal epilepsy due to a meningioma that was removed. As post-operatory complication, she suffered meningitis as well as a maculo-papular erythema caused by the treatment with meropenem. Subsequently, ESL was started and gradually increased until 800 mg/day. Twenty-five days later, the patient developed an Erythema Multiforme Major (EMM). Strong positive immediate reaction was induced by prick test with carbamazepine (CBZ) and ESL at 0.01 and 0.1% within 15 and 30 minutes; however the delayed reading at 48 hours was negative. The patient was not carrier of the HLA alleles A3101 and B1502 associated with CBZ induced EMM. The hypersensitivity pathogenic mechanism of EMM is unclear and a delayed hypersensitivity process is speculated. However, the patch and intradermal tests in our patient did not show a delayed reaction but an immediate cutaneous one. A first allergic episode may elicit a massive nonspecific activation of the immune system, providing an enhanced expression of co-stimulatory molecules that decreases the level of tolerance to other drugs. When prescribing ESL, we suggest ruling out previous CADR, especially to CBZ and oxcarbazepine but also other chemically unrelated drugs such as beta-lactams. PMID:25422574

  7. 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.

  8. 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. PMID:24260733

  9. 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. PMID:27292007

  10. Cutaneous adverse drug reaction type erythema multiforme major induced by eslicarbazepine.

    PubMed

    Massot, Andreu; Gimenez-Arnau, Ana

    2014-10-01

    Severe skin reactions occur less frequently with eslicarbazepine (ESL) than with the other aromatic anticonvulsants. We report the first case of cutaneous adverse drug reaction (CADR) to ESL and co-sensitization between ESL and betalactams. A 41-year-old white woman developed focal epilepsy due to a meningioma that was removed. As post-operatory complication, she suffered meningitis as well as a maculo-papular erythema caused by the treatment with meropenem. Subsequently, ESL was started and gradually increased until 800 mg/day. Twenty-five days later, the patient developed an Erythema Multiforme Major (EMM). Strong positive immediate reaction was induced by prick test with carbamazepine (CBZ) and ESL at 0.01 and 0.1% within 15 and 30 minutes; however the delayed reading at 48 hours was negative. The patient was not carrier of the HLA alleles A3101 and B1502 associated with CBZ induced EMM. The hypersensitivity pathogenic mechanism of EMM is unclear and a delayed hypersensitivity process is speculated. However, the patch and intradermal tests in our patient did not show a delayed reaction but an immediate cutaneous one. A first allergic episode may elicit a massive nonspecific activation of the immune system, providing an enhanced expression of co-stimulatory molecules that decreases the level of tolerance to other drugs. When prescribing ESL, we suggest ruling out previous CADR, especially to CBZ and oxcarbazepine but also other chemically unrelated drugs such as beta-lactams. PMID:25422574

  11. 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

  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. PMID:25269572

  13. Telaprevir may induce adverse cutaneous reactions by a T cell immune-mediated mechanism.

    PubMed

    Federico, Alessandro; Aitella, Ernesto; Sgambato, Dolores; Savoia, Alfonso; De Bartolomeis, Fabio; Dallio, Marcello; Ruocco, Eleonora; Pezone, Luciano; Abbondanza, Ciro; Loguercio, Carmela; Astarita, Corrado

    2015-01-01

    The HCV protease inhibitor telaprevir associated with peginterferon-alpha and ribavirin, was widely used in the recent past as standard treatment in HCV genotype-1 infected patients. Telaprevir improves the sustained virology response rates, but at the same time increases the frequency of adverse cutaneous reactions. However, mechanisms through which telaprevir induces cutaneous lesions are not yet defined. A 50-year-old woman, affected by HCV genotype 1b, was admitted to our Department for a telaprevir-related severe cutaneous eruptions, eight weeks after starting a triple therapy (telaprevir associated with Peginterferon-alpha and ribavirin). Mechanisms of cutaneous reactions were investigated by skin tests with non-irritating concentrations of telaprevir and by activating in vitro T lymphocyte with different concentrations. Immediate and delayed responses to skin testing were negative, but the drug-induced lymphocytes activation was significantly higher as compared to patient's baseline values and to parallel results obtained in three healthy subjects (p < 0.05). In conclusion, adverse cutaneous reactions of our patient were caused by a telaprevir-induced T-cell dependent immune mechanism. PMID:25864225

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

    PubMed

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

    2015-11-01

    The CD32a immunoglobulin G (IgG) receptor (Fcγ receptor IIa) is a potential therapeutic target for diseases in which IgG immune complexes (ICs) mediate inflammation, such as heparin-induced thrombocytopenia, rheumatoid arthritis, and systemic lupus erythematosus. Monoclonal antibodies (mAbs) are a promising strategy for treating such diseases. However, IV.3, perhaps the best characterized CD32a-blocking mAb, was recently shown to induce anaphylaxis in immunocompromised "3KO" mice. This anaphylactic reaction required a human CD32a transgene because mice lack an equivalent of this gene. The finding that IV.3 induces anaphylaxis in CD32a-transgenic mice was surprising because IV.3 had long been thought to lack the intrinsic capacity to trigger cellular activation via CD32a. Such an anaphylactic reaction would also limit potential therapeutic applications of IV.3. In the present study, we examine the molecular mechanisms by which IV.3 induces anaphylaxis. We now report that IV.3 induces anaphylaxis in immunocompetent CD32a-transgenic "FCGR2A" mice, along with the novel finding that IV.3 and 2 other well-characterized CD32a-blocking mAbs, AT-10 and MDE-8, also induce severe thrombocytopenia in FCGR2A mice. Using recombinant variants of these same mAbs, we show that IgG "Fc" effector function is necessary for the induction of anaphylaxis and thrombocytopenia in FCGR2A mice. Variants of these mAbs lacking the capacity to activate mouse IgG receptors not only failed to induce anaphylaxis or thrombocytopenia, but also very potently protected FCGR2A mice from near lethal doses of IgG ICs. Our findings show that effector-deficient IV.3, AT-10, and MDE-8 are promising candidates for developing therapeutic mAbs to treat CD32a-mediated diseases. PMID:26396093

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

    PubMed Central

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

    2015-01-01

    The CD32a immunoglobulin G (IgG) receptor (Fcγ receptor IIa) is a potential therapeutic target for diseases in which IgG immune complexes (ICs) mediate inflammation, such as heparin-induced thrombocytopenia, rheumatoid arthritis, and systemic lupus erythematosus. Monoclonal antibodies (mAbs) are a promising strategy for treating such diseases. However, IV.3, perhaps the best characterized CD32a-blocking mAb, was recently shown to induce anaphylaxis in immunocompromised “3KO” mice. This anaphylactic reaction required a human CD32a transgene because mice lack an equivalent of this gene. The finding that IV.3 induces anaphylaxis in CD32a-transgenic mice was surprising because IV.3 had long been thought to lack the intrinsic capacity to trigger cellular activation via CD32a. Such an anaphylactic reaction would also limit potential therapeutic applications of IV.3. In the present study, we examine the molecular mechanisms by which IV.3 induces anaphylaxis. We now report that IV.3 induces anaphylaxis in immunocompetent CD32a-transgenic “FCGR2A” mice, along with the novel finding that IV.3 and 2 other well-characterized CD32a-blocking mAbs, AT-10 and MDE-8, also induce severe thrombocytopenia in FCGR2A mice. Using recombinant variants of these same mAbs, we show that IgG “Fc” effector function is necessary for the induction of anaphylaxis and thrombocytopenia in FCGR2A mice. Variants of these mAbs lacking the capacity to activate mouse IgG receptors not only failed to induce anaphylaxis or thrombocytopenia, but also very potently protected FCGR2A mice from near lethal doses of IgG ICs. Our findings show that effector-deficient IV.3, AT-10, and MDE-8 are promising candidates for developing therapeutic mAbs to treat CD32a-mediated diseases. PMID:26396093

  16. 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. PMID:17321559

  17. Dominant roles of Fenton reaction in sodium nitroprusside-induced chondrocyte apoptosis.

    PubMed

    Quan, Ying-Yao; Qin, Gui-Qi; Huang, Hao; Liu, Yu-Hong; Wang, Xiao-Ping; Chen, Tong-Sheng

    2016-05-01

    Sodium nitroprusside (SNP) has been widely used as an exogenous nitric oxide (NO) donor to explore the molecular mechanism of NO-mediated chondrocyte apoptosis during the latest two decades. We have recently found that NO-independent ROS play a key role in SNP-induced apoptosis in rabbit chondrocytes. This study aims to investigate what kind of ROS and how the reliable ROS mediators mediate the SNP-induced apoptosis. Data shows that SNP and NO-exhausted SNP (SNPex) induced ROS production or cytotoxicity to identically degree. SNP induced a marked increase in iron ions, superoxide anion (O2(•-)), hydrogen peroxide (H2O2) and hydroxyl radical ((•)OH) level. H2O2 scavenger (CAT) and (•)OH scavenger (DMSO) significantly inhibited SNP-induced chondrocyte apoptosis. Iron ions chelator (DFO) entirely prevented SNP-induced chondrocyte apoptosis. In contrast, O2(•-) scavenger (SOD) and glutathione depletion agent (BSO) promoted SNP-induced cytotoxicity. K3[Fe(CN)6] exhibited no cytotoxicity, and H2O2 alone up to 250µM or iron ions alone up to 90µM is non-cytotoxic to chondrocytes. Combination of 25µM FeSO4 and 100µM H2O2 in the presence of BSO induced chondrocyte death similar to SNP treatment. Fetal bovine serum (FBS) enhanced iron ions release from SNP and the cytotoxicity of SNP. Our data shows that the extracellular Fenton reaction between iron ions released from SNP and H2O2 induced by SNP plays a key role in SNP-induced chondrocyte apoptosis. Overall, our results indicate that the potential of SNP to increase iron ions and ROS should be especially considered for some biological functions and, possibly, also for clinical applications of this drug. PMID:26923801

  18. 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

  19. An ab initio variationally computed room-temperature line list for (32)S(16)O3.

    PubMed

    Underwood, Daniel S; Tennyson, Jonathan; Yurchenko, Sergei N

    2013-07-01

    Ab initio potential energy and dipole moment surfaces are computed for sulfur trioxide (SO3) at the CCSD(T)-F12b level of theory with appropriate triple-zeta basis sets. The analytical representations of these surfaces are used, with a slight correction, to compute pure rotational and rotation-vibration spectra of (32)S(16)O3 using the variational nuclear motion program TROVE. The calculations considered transitions in the region 0-4000 cm(-1) with rotational states up to J = 85. The resulting line list of 174,674,257 transitions is appropriate for modelling room temperature (32)S(16)O3 spectra. Good agreement is found with the observed infrared absorption spectra and the calculations are used to place the measured relative intensities on an absolute scale. A list of 10,878 experimental transitions is provided in a form suitable for inclusion in standard atmospheric and planetary spectroscopic databases. PMID:23579443

  20. 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.

  1. Relationship between serum acetaminophen concentration and N-acetylcysteine-induced adverse drug reactions.

    PubMed

    Zyoud, Sa'ed H; Awang, Rahmat; Sulaiman, Syed Azhar Syed; Khan, Halilol Rahman Mohamed; Sawalha, Ansam F; Sweileh, Waleed M; Al-Jabi, Samah W

    2010-09-01

    Intravenous N-acetylcysteine is usually regarded as a safe antidote. However, during the infusion of the loading dose, different types of adverse drug reactions (ADR) may occur. The objective of this study was to investigate the relation between the incidence of different types of ADR and serum acetaminophen concentration in patients presenting to the hospital with acetaminophen overdose. This is a retrospective study of patients admitted to the hospital for acute acetaminophen overdose over a period of 5 years (1 January 2004 to 31 December 2008). Parametric and non-parametric tests were used to test differences between groups depending on the normality of the data. SPSS 15 was used for data analysis. Of 305 patients with acetaminophen overdose, 146 (47.9%) were treated with intravenous N-acetylcysteine and 139 (45.6%) were included in this study. Different types of ADR were observed in 94 (67.6%) patients. Low serum acetaminophen concentrations were significantly associated with cutaneous anaphylactoid reactions but not other types of ADR. Low serum acetaminophen concentration was significantly associated with flushing (p < 0.001), rash (p < 0.001) and pruritus (p < 0.001). However, there were no significant differences in serum acetaminophen concentrations between patients with and without the following ADR: gastrointestinal reactions (p = 0.77), respiratory reactions (p = 0.96), central nervous reactions (p = 0.82) and cardiovascular reactions (p = 0.37). In conclusion, low serum acetaminophen concentrations were associated with higher cutaneous anaphylactoid reactions. Such high serum acetaminophen concentrations may be protective against N-acetylcysteine-induced cutaneous ADR. PMID:20374238

  2. Measurements and Modeling of (16)O(12)C(17)O Spectroscopic Parameters at 2µm

    NASA Astrophysics Data System (ADS)

    Jacquemart, D.; Sung, K.; Brown, L. R.; Coleman, M.; Mantz, A. W.; Smith, M. A. H.

    2014-06-01

    In the present study, line-intensity measurements for 16O12C17O were performed using a high-resolution Fourier transform spectrometer (Bruker IFS-125HR) together with a Herriott cell allowing a 20.956 m absorption path. For this, a 17O-enriched CO2 gas sample mixture was used. The 16O12C17O isotopologue abundance in the sample was determined to be 0.3991 by mass spectrometry. Since a collisional narrowing effect has been observed, the Rautian profile was systematically used instead of the Voigt profile. Finally, around 1000 transitions were studied between 4604 and 5126 cm-1 involving 15 bands of the 16O12C17O isotopologue. For each of the 15 bands, transition dipole moments and Herman-Wallis factors were derived, which also enabled a global comparison with theoretical calculations and predictions achieved for carbon dioxide. For the measured and calculated line positions, the accuracy is between 0.1 - 1×10-3 cm-1. For line intensities, depending on the intensity of the band, accuracies are between 2 - 3 % for 5 cold bands and 2 hot bands and between 6 - 30 % for 8 weaker hot bands. Results from this work are compared to previous works and to HITRAN 2012. Complete line lists were generated to support atmospheric remote sensing for the Earth (e.g. GOSAT, OCO-2 ...), Mars and Venus.

  3. 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.

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

    DOE PAGESBeta

    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

  5. 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.

  6. 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.

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

    DOE PAGESBeta

    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 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

  8. Negative binomial fits to multiplicity distributions from central collisions of {sup 16}O + Cu at 14.6A GeV/c and intermittency

    SciTech Connect

    Tannenbaum, M.J.

    1994-10-14

    An `intermittency` analysis of charged particle multiplicity data from the target multiplicy array (TMA) in central collisions of {sup 16}O+Cu at 14.6 A{times}GeV/c has been published by the AGS-E802 collaboration. The centrality cut was made using the Zero degree Calorimeter and requiring that the forward energy be less than one projectile nucleon (i.e. T{sub ZCAL} <13.6 GeV). In agreement with previous measurements, an apparent power-law growth of Normalized Factorial moments with decreasing pseudorapidity interval was observed in the range 1.0{ge}{delta}{eta}{ge}0.1. In the present work, multiplicity distributions in individual pseudorapidity bins are presented for the same data. These distributions are excellently fit by Negative Binomial Distributions (NBD) in all {delta}{eta} bins, allowing, for the first time, a systematic formulation of the subject of `intermittency` in terms of distributions, rather than moments. In agreement with all previous measurements of NBD fits to multiplicity distributions in hadron and lepton reactions, the k parameter of the NBD fit for central {sup 16}O+Cu collisions is found to exhibit an apparently linear increase with the {delta}{eta} interval, albeit with a much steeper slope than for the other reactions, and a non-zero intercept, k(0){ne}0. True intermittency, {xi}{yields}0, would occur if the intercept k(0){yields}0, which is not observed in any experiment. The correlation length for central {sup 16}O+Cu collisions, although smaller than expected, is quite finite and can be measured - which means that a length scale exists in these collisions and therefore there is no intermittency in the multiplicity fluctuations.

  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. 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).

  11. 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. PMID:26523942

  12. From the HINDAS Project: Excitation Functions for Residual Nuclide Production by Proton-Induced Reactions

    SciTech Connect

    Michel, R.; Gloris, M.; Protoschill, J.; Uosif, M.A.M.; Weug, M.; Herpers, U.; Kuhnhenn, J.; Kubik, P.-W.; Schumann, D.; Synal, H.-A.; Weinreich, R.; Leya, I.; David, J.C.; Leray, S.; Duijvestijn, M.; Koning, A.; Kelic, A.; Schmidt, K.H.; Cugnon, J.

    2005-05-24

    A survey is given about efforts undertaken during the HINDAS project to investigate the energy dependence of residual nuclide production by proton-induced reactions from thresholds up to 2.6 GeV. For proton-induced reactions, our experiments aimed to further develop and complete the cross-section database that was established by our collaboration in recent years. It was extended to the heavy-target elements Ta, W, Pb, and Bi for energies up to 2.6 GeV. In addition, new measurements for the target element iron were performed up to 2.6 GeV and for natural uranium for energies from 21 MeV to 69 MeV. For the target element lead, a comprehensive set of excitation functions published recently was completed by AMS-measurements of cross sections for the production of the long-lived radionuclides Be-10, Al-26, Cl-36, and I-129 and by mass spectrometric measurements for stable and radioactive rare gas isotopes of He, Ne, Ar, Kr, and Xe. Comprehensive tests of the nuclear-reaction codes TALYS and INCL4+ABLA, which were developed within the HINDAS project, were performed with the new experimental results over the entire energy range.

  13. Hydroxyapatite-titanium interface reaction induced by keV electron irradiation

    NASA Astrophysics Data System (ADS)

    Torrisi, L.; Foti, G.

    1992-03-01

    Thin films of hydroxyapatite bioceramic, 5-50 Å in thickness, have been deposited on ion cleaned titanium surfaces to study the chemical-physical adhesion of metal-ceramic interfaces of biomedical devices (orthopaedic and dentistry prosthesis). Film deposition was performed in ultrahigh vacuum condition (10 -10 mbar) using 5 keV argon sputtering of hydroxyapatite matrix; the film thickness was measured in situ with Auger electron spectroscopy. The hydroxyapatite-titanium interface was irradiated with an electron beam of 0.5-5 keV energy and 0.2-2 A/cm 2 current density. During electron irradiation, Auger spectra show chemical shifts of phosphorus, titanium and oxygen peaks. The released electron energy induces modifications in the tetraedric phosphorus-oxygen groups with production of new chemical bonds between phosphorus, oxygen and titanium. Oxygen, for example, diffuses into the titanium interface forming titanium oxide. Chemical reactions induced by electron irradiation are driven by the metal-ceramic interface. Near the interface a strong and fast effect is observed while far from the interface a weak and slow effect occurs. Chemical reactions depend on the electron irradiation dose showing an inhibition threshold at about 10 19 e/cm 2 and, near the interface, a saturation condition at about 5 × 10 20 e/cm 2. Titanium-ceramic chemical reactions are inhibited if the substrate titanium surface is rich in oxide.

  14. Chemical reactions induced by oscillating external fields in weak thermal environments.

    PubMed

    Craven, Galen T; Bartsch, Thomas; Hernandez, Rigoberto

    2015-02-21

    Chemical reaction rates must increasingly be determined in systems that evolve under the control of external stimuli. In these systems, when a reactant population is induced to cross an energy barrier through forcing from a temporally varying external field, the transition state that the reaction must pass through during the transformation from reactant to product is no longer a fixed geometric structure, but is instead time-dependent. For a periodically forced model reaction, we develop a recrossing-free dividing surface that is attached to a transition state trajectory [T. Bartsch, R. Hernandez, and T. Uzer, Phys. Rev. Lett. 95, 058301 (2005)]. We have previously shown that for single-mode sinusoidal driving, the stability of the time-varying transition state directly determines the reaction rate [G. T. Craven, T. Bartsch, and R. Hernandez, J. Chem. Phys. 141, 041106 (2014)]. Here, we extend our previous work to the case of multi-mode driving waveforms. Excellent agreement is observed between the rates predicted by stability analysis and rates obtained through numerical calculation of the reactive flux. We also show that the optimal dividing surface and the resulting reaction rate for a reactive system driven by weak thermal noise can be approximated well using the transition state geometry of the underlying deterministic system. This agreement persists as long as the thermal driving strength is less than the order of that of the periodic driving. The power of this result is its simplicity. The surprising accuracy of the time-dependent noise-free geometry for obtaining transition state theory rates in chemical reactions driven by periodic fields reveals the dynamics without requiring the cost of brute-force calculations. PMID:25702003

  15. Chemical reactions induced by oscillating external fields in weak thermal environments

    NASA Astrophysics Data System (ADS)

    Craven, Galen T.; Bartsch, Thomas; Hernandez, Rigoberto

    2015-02-01

    Chemical reaction rates must increasingly be determined in systems that evolve under the control of external stimuli. In these systems, when a reactant population is induced to cross an energy barrier through forcing from a temporally varying external field, the transition state that the reaction must pass through during the transformation from reactant to product is no longer a fixed geometric structure, but is instead time-dependent. For a periodically forced model reaction, we develop a recrossing-free dividing surface that is attached to a transition state trajectory [T. Bartsch, R. Hernandez, and T. Uzer, Phys. Rev. Lett. 95, 058301 (2005)]. We have previously shown that for single-mode sinusoidal driving, the stability of the time-varying transition state directly determines the reaction rate [G. T. Craven, T. Bartsch, and R. Hernandez, J. Chem. Phys. 141, 041106 (2014)]. Here, we extend our previous work to the case of multi-mode driving waveforms. Excellent agreement is observed between the rates predicted by stability analysis and rates obtained through numerical calculation of the reactive flux. We also show that the optimal dividing surface and the resulting reaction rate for a reactive system driven by weak thermal noise can be approximated well using the transition state geometry of the underlying deterministic system. This agreement persists as long as the thermal driving strength is less than the order of that of the periodic driving. The power of this result is its simplicity. The surprising accuracy of the time-dependent noise-free geometry for obtaining transition state theory rates in chemical reactions driven by periodic fields reveals the dynamics without requiring the cost of brute-force calculations.

  16. 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

  17. Hot fusion-evaporation cross sections of 45Sc -induced reactions with lanthanide targets

    NASA Astrophysics Data System (ADS)

    Werke, T. A.; Mayorov, D. A.; Alfonso, M. C.; Bennett, M. E.; DeVanzo, M. J.; Frey, M. M.; Tereshatov, E. E.; Folden, C. M.

    2015-09-01

    Background: 45Sc has rarely been studied as a projectile in fusion-evaporation reactions. The synthesis of new superheavy elements with Z >118 will require projectiles with Z >20 , and 45Sc could potentially be used for this purpose. Purpose: Cross sections were measured for the x n and p x n exit channels in the reactions of 45Sc with lanthanide targets for comparison to previous measurements of 48Ca reacting with similar targets. These data provide insight on the survival of spherical, shell-stabilized nuclei against fission, and could have implications for the discovery of new superheavy elements. Methods: Beams of 45Sc6 + were delivered from the K500 superconducting cyclotron at Texas A&M University with an energy of ≈5 MeV /nucleon . Products were purified using the Momentum Achromat Recoil Spectrometer, and excitation functions were measured for reactions of 45Sc+156-158,160Gd, 159Tb , and 162Dy at five or more energies each. Evaporation residues were identified by their characteristic α -decay energies. Experimental data were compared to a simple theoretical model to study each step in the fusion-evaporation process. Results: The maximum measured 4 n cross sections for the reactions 45Sc+156-158,160Gd, 159Tb , and 162Dy are 5.8 ±1.7 , 25 ±5 , 39 ±7 , 150 ±20 , 2 .4-1.4+2.3 , and 1.8 ±0.6 μ b , respectively. Proton emission competes effectively with neutron emission from the excited compound nucleus in most cases. The α ,α n , and α 2 n products were also observed in the 45Sc+162Dy reaction. Conclusions: Excitation functions were reported for 45Sc -induced reactions on lanthanide targets for the first time, and these cross sections are much smaller than for 48Ca -induced reactions on the same targets. The relative neutron-deficiency of the compound nuclei leads to significantly increased fissility and large reductions in the survival probability. Little evidence for improved production cross sections due to shell-stabilization was observed.

  18. 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.

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

    ScienceCinema

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

    2010-01-08

    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.

  20. 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.

  1. 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

  2. Observations of shock-induced reaction in liquid bromoform up to 11 GPA

    SciTech Connect

    Sheffield, S.A.; Gustavsen, R.L.; Alcon, R.R.

    1995-09-01

    Shock measurements on bromoform (CHBr{sub 3}) over the past 33 years at Los Alamos have led to speculation that this material undergoes a shock-induced reaction. Ramsay observed that it became opaque after a 1 to 2 {micro}s induction time when shocked to pressures above 6 GPa. McQueen and Isaak observed that it is a strong light emitter above 25 GPa. Hugoniot data start to deviate from the anticipated liquid Hugoniot at pressures above 10 GPa. The authors have used electromagnetic particle velocity gauging to measure wave profiles in shocked liquid bromoform. At pressures below 9 GPa, there is no mechanical evidence of reaction. At a pressure slightly above 10 GPa, the observed wave profiles are similar to those observed in initiating liquid explosives such as nitromethane. Their characteristics are completely different from the two-wave structures observed in shocked liquids where the products are more dense than the reactants. As with explosives, a reaction producing products which are less dense than the reactants is indicated. BKW calculations also indicate that a detonation type reaction may be possible.

  3. Novel conserved structural domains of acrosome reaction-inducing substance are widespread in invertebrates.

    PubMed

    Naruse, Masahiro; Ishikawa, Riho; Sakaya, Hiroshi; Moriyama, Hideaki; Hoshi, Motonori; Matsumoto, Midori

    2011-01-01

    In the starfish Asterias amurensis, acrosome reaction inducing substance (ARIS) is the main factor responsible for allowing sperm to recognize the egg jelly and begin the acrosome reaction (AR). ARIS is a large proteoglycan-like molecule, and its pentasaccharide repeat, Fragment 1 (Fr. 1), is responsible for inducing AR. Here, we investigated the primary structure of ARIS for the first time in order to improve our understanding of its functionality. Electrophoretic analysis revealed that ARIS is a complex of three proteins, all of which are modified by the Fr. 1 sugar chain. Sequencing indicated that there are two novel, conserved domains in all three ARIS proteins: ARIS N-terminus (AR-N) and ARIS C-terminus (AR-C) domains. We also found that other echinoderms possess ARIS proteins that are capable of inducing the AR for homologous sperm, indicating that ARIS proteins may be a ubiquitous component for echinoderm fertilization. Moreover, we identified ARIS-like genes from Ctenophora to Protochordata. PMID:21268183

  4. 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

  5. Forming ceria shell on Au-core by LSPR photothermal induced interface reaction

    NASA Astrophysics Data System (ADS)

    Qu, Y. H.; Liu, F.; Wei, Y.; Gu, C. L.; Zhang, L. H.; Liu, Y.

    2015-07-01

    A novel method for preparing core-shell structure of Au@ceria was presented, which is characterized with using photothermal effect from localized surface plasmon resonance (LSPR) to induce heat, and the heat can trigger the shell formation reactions confined on the surface of the Au nanoparticles (NPs). In short of the preparation procedure, aqueous sol of Au NPs, citric acid, ethylene glycol and cerous nitrate were irradiated with a Xe arc lamp, maintaining the temperature of the sol at 25 °C by cooling and stirring the sol. The Au NPs could generate heat from LSPR, and the heat induced polymerization reaction in the sol, resulting in cerium gel formation which enveloped each of the Au NPs, and the gel containing cerium formed only on the surface of the Au NPs. After calcination, Au@ceria was obtained. This method can be extended for preparing various core@shell nanocomposites in which metal cores possess LSPR effect and the shell formation can be induced by heat.

  6. 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).

  7. Infrared Laser Generation Of Heterogeneous Catalysts And Laser-Induced Reactions At Catalytic Surfaces

    NASA Astrophysics Data System (ADS)

    Danen, Wayne C.; Cheng, , Sheng-San; Iyer, Pradeep K.; Chiou, Shane-Jaw

    1984-05-01

    It has been demonstrated that continuous wave infrared CO2 laser radiation can be util-ized to rapidly produce active catalysts from inert precursors. The activity and selectiv-ity of Ca0 produced from Ca(OH)2 for the isomerization of 1-butene to cis- and trans-2-but-ene is discussed. Variation of the laser irradiation time produces catalytic activity and selectivity qualitatively similar to that resulting from conventional calcination at different temperatures. Pulsed infrared laser-induced reactions at catalytic surfaces are also discussed with emphasis on the dehydrobromination of 2-bromopropane and ethylene elimination from glycine ethyl ester hydrochloride at BaSO4 , A1PO4, and similar surfaces. Correlations are made of the extent of reaction with various experimental parameters including nature of the catalyst, laser frequency, laser fluence, number of laser pulses, and reagent-catalyst ratio.

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

    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.

  9. Activation cross sections of proton induced nuclear reactions on palladium up to 80MeV.

    PubMed

    Tárkányi, F; Ditrói, F; Takács, S; Csikai, J; Hermanne, A; Uddin, M S; Baba, M

    2016-08-01

    Activation cross sections of proton induced nuclear reactions on palladium were measured up to 80MeV by using the stacked foil irradiation technique and gamma ray spectrometry. The beam intensity, the incident energy and the energy degradation were controlled by a method based on flux constancy via normalization to the excitation functions of monitor reactions measured in parallel. Excitation functions for direct and cumulative cross-sections were measured for the production of (104m,104g,105g,106m,110m)Ag, (100,101)Pd, (99m,99g,100,101m,101g,102m,102g,105)Rh and (103,97)Ru radioisotopes. The cross section data were compared with the theoretical predictions of TENDL-2014 and -2015 libraries. For practical applications thick target yields were derived from the measured excitation functions. Application in the field of medical radionuclide production is shortly discussed. PMID:27235887

  10. Fabrication of ceramic microspheres by diffusion-induced sol-gel reaction in double emulsions.

    PubMed

    Zhang, Lei; Hao, Shaochang; Liu, Bing; Shum, Ho Cheung; Li, Jiang; Chen, Haosheng

    2013-11-27

    We demonstrate an approach to prepare zirconium dioxide (ZrO2) microspheres by carrying out a diffusion-induced sol-gel reaction inside double emulsion droplets. A glass capillary microfluidic device is introduced to generate monodisperse water-in-oil-in-water (W/O/W) double emulsions with a zirconium precursor as the inner phase. By adding ammonia to the continuous aqueous phase, the zirconium precursor solution is triggered to gel inside the emulsions. The double emulsion structure enhances the uniformity in the rate of the sol-gel reaction, resulting in sol-gel microspheres with improved size uniformity and sphericity. ZrO2 ceramic microspheres are formed following subsequent drying and sintering steps. Our approach, which combines double-emulsion-templating and sol-gel synthesis, has great potential for fabricating versatile ceramic microspheres for applications under high temperature and pressure. PMID:23865771

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

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

    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.

  12. Excitation function of (3)He-particle induced nuclear reactions on natural palladium.

    PubMed

    Al-Abyad, M; Tárkányi, F; Ditrói, F; Takács, S

    2014-12-01

    Excitation functions of (3)He-particle induced nuclear reactions on natural palladium were measured using the standard stacked foil technique and high resolution γ-ray spectroscopy. From their threshold energies up to 27MeV, cross-sections for (nat)Pd((3)He,x)(103,104,105,106m,110m,111,112)Ag and (nat)Pd((3)He,x)(104,105,107,111m)Cd reactions were measured. The nuclear model codes TALYS-1.4, and EMPIRE-3.1 were used to describe the formation of these products. The present data were compared to theoretical results and to the available experimental data. Integral yields for some important radioisotopes were determined. PMID:25218461

  13. Asterosap-induced elevation in intracellular pH is indispensable for ARIS-induced sustained increase in intracellular Ca2+ and following acrosome reaction in starfish spermatozoa.

    PubMed

    Kawase, Osamu; Minakata, Hiroyuki; Hoshi, Motonori; Matsumoto, Midori

    2005-02-01

    In the starfish, Asterias amurensis, the cooperation of three components of the egg jelly, namely ARIS (acrosome reaction-inducing substance), Co-ARIS and asterosap, is responsible for the induction of acrosome reaction. For the induction, ARIS alone is enough in high-Ca2+ or high-pH seawater, but, besides ARIS, the addition of either Co-ARIS or asterosap is required in normal seawater. Asterosap transiently increased both the intracellular pH (pHi) and Ca2+ ([Ca2+]i), while ARIS slightly elevated the basal level of [Ca2+]i. However, a sustained elevation of [Ca2+]i and acrosome reaction occurred if sperm were simultaneously treated with ARIS and asterosap. EGTA inhibited the sustained [Ca2+]i elevation and acrosome reaction. The sustained [Ca2+]i elevation and acrosome reaction were highly susceptible to SKF96365 and Ni2+, specific blockers of the store-operated Ca2+ channel (SOC). These results suggest that sustained [Ca2+]i elevation, mediated by the SOC-like channel, is a prerequisite for the acrosome reaction. In high-pH seawater, ARIS alone induced a prominent [Ca2+]i increase and acrosome reaction, which were similarly sensitive to SKF96365. The acrosome reaction was effectively induced by ARIS alone when pHi was artificially increased to more than 7.7. Asterosap increased pHi from 7.6 +/- 0.1 to 7.7 +/- 0.1. Furthermore, the sustained [Ca2+]i elevation and acrosome reaction, induced by a combination of ARIS and asterosap, were drastically inhibited by a slight reduction in pHi. Taking these results into account, we suggest that an asterosap-induced pHi elevation is required for triggering the ARIS-induced sustained [Ca2+]i elevation and consequent acrosome reaction. PMID:15984164

  14. Is atherosclerosis a multifactorial disease or is it induced by a sequence of lipid peroxidation reactions?

    PubMed

    Spiteller, Gerhard

    2005-06-01

    The delivery of not only free cholesterol but also cholesterol esters to cells by low-density lipoprotein (LDL) has hitherto been unstudied. Minor compounds present in mammalian-derived food include cholesterol linoleate and arachidonate. Evidence is presented that these esters are directly incorporated into VLDL and are responsible for the deleterious effects of atherosclerosis. Cholesterol esterified with these polyunsaturated fatty acids (PUFAs) is readily oxidized at the PUFA residue during storage and heating. Apparently, the liver is unable to distinguish between nonoxidized and oxidized cholesterol PUFA esters and also incorporates the latter into VLDL, which is transformed to LDL. When this LDL is transferred to endothelial cells, the toxic products are liberated and induce cell damage. Cell damage is combined with structural changes that influence neighboring cells and cause an influx of Ca2+ ions and activation of phospholipases and lipoxygenases, resulting in production of lipid hydroperoxides (LOOHs). When the level of free PUFAs generated by phospholipases exceeds a certain limit, lipoxygenases commit suicide, causing liberation of iron ions. The latter react with LOOHs and thus induce a switch from enzymatic to nonenzymatic generation of lipid peroxidation (LPO) products. Although the LOO. radicals produced in enzymatic reactions are deactivated within the enzyme complex, LOO. radicals generated in nonenzymatic reactions are able to attack any biological compound, inducing severe damage. Apparently, iron ions and LOOH molecules at the surface of injured cells transfer the nonenzymatic LPO reactions to the phospholipid layer of bypassing lipoproteins, thus explaining why inflammatory diseases, such as diabetes, are combined with atherogenesis. PMID:16037257

  15. 16O excesses in olivine inclusions in Yamato-86009 and Murchison chondrites and their relation to CAIs.

    PubMed

    Hiyagon, H; Hashimoto, A

    1999-02-01

    In situ ion microprobe analyses of oxygen isotopes in Yamato-86009 and Murchison chondrites show that they contain abundant olivine-rich inclusions that have large oxygen-16 (16O) excesses, similar to those in spinel grains in calcium-aluminium-rich inclusions in Allende and other carbonaceous chondrites. The existence of 16O-enriched olivine-rich inclusions suggests that oxygen isotopic anomalies were more extensive in the early solar system than was previously thought and that their origin may be attributed to a nebular chemical process rather than to an unidentified 16O-rich carrier of presolar origin. PMID:9933162

  16. Identification of fission-like events in the {sup 16}O + {sup 181}Ta system: Mass and isotopic yield distribution

    SciTech Connect

    Sharma, Vijay R.; Yadav, Abhishek; Singh, Devendra P.; Unnati,; Singh, B. P.; Prasad, R.; Singh, Pushpendra P.; Sharma, Manoj K.; Kumar, R.; Golda, K. S.; Sinha, A. K.

    2011-07-15

    In this paper, nuclear reaction cross sections for 24 fission-like fragments (30{<=}Z{<=}60) have been measured for the 6.5 MeV/A {sup 16}O + {sup 181}Ta system. The recoil-catcher activation technique was employed followed by off-line {gamma} spectroscopy. The isotopic yield distributions for yttrium and indium isotopes have been obtained from the experimental data. The variance of the presently measured isotopic yield distributions have been found to be in agreement with the literature values. However, the variance of the mass distribution of fission residues has found to be narrower as compared to other relatively heavier systems. A self-consistent approach to determining the isobaric charge dispersion parameters has been adopted. The measured fission cross sections at 97 and 100 MeV are satisfactorily described by a statistical model code. An attempt has been made to explain the production cross sections of intermediate mass residues in the fission of heavy residues populated via complete and/or incomplete fusion processes.

  17. Development of CNS Active Target for Deuteron Induced Reactions with High Intensity Exotic Beam

    NASA Astrophysics Data System (ADS)

    Ota, Shinsuke; Tokieda, H.; Lee, C. S.; Kojima, R.; Watanabe, Y. N.; Corsi, A.; Dozono, M.; Gibelin, J.; Hashimoto, T.; Kawabata, T.; Kawase, S.; Kubono, S.; Kubota, Y.; Maeda, Y.; Matsubara, H.; Matsuda, Y.; Michimasa, S.; Nakao, T.; Nishi, T.; Obertelli, A.; Otsu, H.; Santamaria, C.; Sasano, M.; Takaki, M.; Tanaka, Y.; Leung, T.; Uesaka, T.; Yako, K.; Yamaguchi, H.; Zenihiro, J.; Takada, E.

    An active target system called CAT, has been developed aiming at the measurement of deuteron induced reactions with high intensity beams in inverse kinematics. The CAT consists of a time projection chamber using THGEM and an array of Si detectors or NaI scintilators. The effective gain for the recoil particle is deisgned to be 5 - 10 × 103, while one for the beam is reduced by 102 using mesh grid to match the amplified signal to the dynamic range same as the one for recoil particle. The structure of CAT and the effect of the mesh grid are reported.

  18. Fission probabilities of 242Am,243Cm , and 244Cm induced by transfer reactions

    NASA Astrophysics Data System (ADS)

    Kessedjian, G.; Jurado, B.; Barreau, G.; Marini, P.; Mathieu, L.; Tsekhanovich, I.; Aiche, M.; Boutoux, G.; Czajkowski, S.; Ducasse, Q.

    2015-04-01

    We have measured the fission probabilities of 242Am,243Cm , and 244Cm induced by the transfer reactions 243Am(3He,4He) ,243Am(3He,t ) , and 243Am(3He,d ) , respectively. The details of the experimental procedure and a rigorous uncertainty analysis, including a correlation matrix, are presented. For 243Cm our data show clear structures well below the fission threshold. To our knowledge, it is the first time that these structures have been observed for this nucleus. We have compared the measured fission probabilities to calculations based on the statistical model to obtain information on the fission barriers of the produced fissioning nuclei.

  19. 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

  20. 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*.

  1. Neutron-induced reaction studies at FIGARO using a spallation source

    NASA Astrophysics Data System (ADS)

    Rochman, D.; Haight, R. C.; O'Donnell, J. M.; Devlin, M.; Ethvignot, T.; Granier, T.

    2004-05-01

    A description is given of the new flexible facility Fast Neutron-Induced Gamma-Ray Observer (FIGARO) at the Los Alamos Neutron Science Center. FIGARO is designed to study fast-neutron-induced reactions that result in the emission of γ rays and neutrons, using the white neutron beam of the Weapons Neutron Research Facility. The emitted neutrons and γ rays are detected by several liquid scintillators and one high-resolution germanium or one barium-fluoride detector, respectively. As an example, the inelastic neutron scattering on Si from 4 to 20 MeV is presented and the results are compared with predictions of the nuclear model calculations performed with the codes GNASH and EMPIRE II.

  2. 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.

  3. 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.

  4. 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.

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

    SciTech Connect

    Tonse, S.

    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 studies in terms of the nuclear stopping power and is compared to the predictions of various models. 7 refs., 2 figs.

  6. 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.

  7. Elastic and inelastic scattering of /sup 16/O by /sup 26/Mg

    SciTech Connect

    Rotberg, V.H.; Mittig, W.

    1980-10-01

    Angular distributions and excitation functions for the elastic and inelastic (2/sup +/,1.81 MeV) scattering of /sup 16/O ions by /sup 26/Mg have been measured in the energy range from 22 up to 50 MeV. The data were analyzed in the coupled channel scheme with different potentials. The inelastic scattering data are found to be important to distinguish between optical model parameter sets. The deformation parameter delta/sub n/=..beta../sub n/R is extracted and found to be potential dependent. It is compared to the Coulomb deformation delta/sub C/.

  8. 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.

  9. 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. PMID:24140924

  10. PKA activation in concert with ARIS and asterosap induces the acrosome reaction in starfish.

    PubMed

    Islam, M Sadiqul; Kawase, O; Hase, S; Hoshi, M; Matsumoto, M

    2006-11-01

    The acrosome reaction (AR) is a fundamental event for fertilization, which is induced in concert with acrosome reaction-inducing substance (ARIS) and asterosap, both of which are components of starfish egg jelly (EJ). During the AR, a spermatozoon undergoes a series of physiological changes, such as in intracellular cGMP concentration ([cGMP]i), pHi and intracellular Ca2+ concentration ([Ca2+]i). Affinity purification of cGMP-binding protein resulted in the isolation of a regulatory subunit of the cAMP-dependent protein kinase A (PKA), suggesting the involvement of a cAMP-dependent pathway in the AR. By using a cAMP enzyme immunoassay, [cAMP]i was found to increase in starfish spermatozoa when stimulated with ARIS and asterosap. ARIS could also increase the [cAMP]i in the presence of high pH seawater. Pretreatment of spermatozoa with two specific and cell-permeable PKA inhibitors, H89 and KT5720, prevented the induction of the AR in a concentration-dependent manner. These results suggest that PKA activity participates in the induction of the AR with ARIS and asterosap. To investigate this, we have cloned a gene that encodes a regulatory subunit of PKA that had been identified in starfish spermatozoa. PMID:17266791

  11. Anteroposterior dynamic balance reactions induced by circular translation of the visual field.

    PubMed

    Séverac Cauquil, A; Bessou, M; Dupui, P; Bessou, P

    1996-01-01

    The anteroposterior sway of subjects under conditions of spontaneous dynamic balance on a wobbly platform was measured during visual stimulation by a visual target executing a circular trajectory in the frontal plane. The target was either a component of the whole moving visual scene or moving on a stationary background. With the former stimulation, obtained through the use of rotating prismatic glasses, every point of the visual field appeared to describe a circular trajectory around its real position so that the whole visual field appeared to be circularly translated, undistorted, inducing a binocular pursuit movement. Under these conditions, stereotyped anteroposterior dynamic balance reactions synchronous with the position of the stimulus were elicited. The latter stimulation consisted of pursuing a luminous target describing a trajectory similar to that of the fixation point seen through the rotating prisms on the same, this time stable, visual background. Although pursuit eye movements were comparable, as demonstrated by electro-oculographic recordings, no stereotyped equilibration reaction was induced. It is concluded that the translatory motion of the background image on the retina in the latter experiments contributed to the body's stability as well as to the perception of a stable environment. PMID:8865085

  12. Fenton Reaction-Generated Advanced Oxidation Protein Products Induces Inflammation in Human Embryonic Kidney Cells.

    PubMed

    Bochi, Guilherme Vargas; Torbitz, Vanessa Dorneles; Santos, Roberto Christ Vianna; Cubillos-Rojas, Monica; López, José Luis Rosa; Siebel, Anna Maria; Gomes, Patrícia; de Oliveira, Jarbas Rodrigues; Moresco, Rafael Noal

    2016-08-01

    Fenton reaction is a new mechanism able to generate advanced oxidation protein products (AOPPs) by exposing the human serum albumin to the Fenton system. Here, we characterized the effects of Fenton reaction-generated advanced oxidation protein products (AOPP-FR) on the gene transcription of the nuclear factor-κB (NF-κB), cyclooxygenase-2 (COX-2), and interleukin-6 (IL-6) in human embryonic kidney cells (HEK 293). To investigate the effects of AOPP-FR and AOPP-HOCl on transcription of inflammatory genes, the NF-κB, COX-2, and IL-6 luciferase promoter activities were analyzed. AOPP-FR and AOPP-HOCl were able to induce the activation of the gene transcription of NF-κB, COX-2, and IL-6 in HEK 293 cells. However, the effects of AOPP-FR were significantly higher than the effects of AOPP-HOCl in relation to COX-2 and IL-6. AOPP-FR induces the activation of the gene transcription of NF-κB, COX-2, and IL-6 and may represent a novel pathogenic mediator of inflammation in kidney. PMID:27145783

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

    NASA Astrophysics Data System (ADS)

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

    2003-06-01

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

  14. A facility for studying radiative capture reactions induced with radioactive beams at ISAC

    NASA Astrophysics Data System (ADS)

    D'Auria, J. M.; Buchmann, L.; Hutcheon, D.; Lipnik, P.; Hunter, D.; Rogers, J.; Helmer, R.; Giesen, U.; Olin, A.; Bricault, P.; Bateman, N.

    The measurement of low energy fusion reactions of importance to nuclear astrophysics scenarios are a prime objective of the physics program of the new ISAC facility, located at TRIUMF in Vancouver, Canada. Intense radioactive beams of 19Ne, 14,15O, 20,21Na, 17,18F and other low Z species with energies in the range of 0.15 to 1.5 MeV/mass unit will be available to measure cross sections and resonance strengths of alpha and proton induced reactions. An important component of the experimental configuration will be a new Recoil Product Detection Facility (RPDF) consisting of a windowless gas target, surrounded by a gamma array, while the recoils are separated from the intense radioactive beam using a Electro-Magnetic Separator (EMS) employing Wien filters. The recoiling reaction products will then be detected using either a Si μ-strip array or a gas filled detector. Using these devices along with coincidence requirements and time-of-flight conditions a background reduction factor of the order of 10 +15 is the present goal.

  15. A facility for studying radiative capture reactions induced with radioactive beams at ISAC

    NASA Astrophysics Data System (ADS)

    Giesen, U.; Buchmann, L.; Hutcheon, D.; Helmer, R.; Olin, A.; Bricault, P.; Bateman, N.; D'Auria, J. M.; Lipnik, P.; Hunter, D.; Rodgers, J.

    1996-04-01

    The measurement of low energy fusion reactions of importance to nuclear astrophysics scenarios are a prime objective of the physics program of the new ISAC facility, located at TRIUMF in Vancouver, Canada. Intense radioactive beams of e,19Ne, ,14,15O, a,20,21Na, 17,18F and other low Z species with energies in the range of 0.15 to 1.5 MeV/mass unit will be available to measure cross sections and resonance strengths of alpha and proton induced reactions, An important component of the experimental configuration will be a new Recoil Product Detection Facility (RPDF) consisting of a windowless gas target, surrounded by a gamma array, while the recoils are separated from the intense radioactive beam using a Electro-Magnetic Separator (EMS) employing Wien filters. The recoiling reaction products will then be detected using either a Si μ-strip array or a gas filled detector. Using these devices along with coincidence requirements and time-of-flight conditions a background reduction factor of the order of 10+15 is the present goal.

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

    NASA Astrophysics Data System (ADS)

    Gharaei, R.; Sheibani, J.

    2016-05-01

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

  17. Specific binding of acrosome-reaction-inducing substance to the head of starfish spermatozoa.

    PubMed

    Ushiyama, A; Araki, T; Chiba, K; Hoshi, M

    1993-05-01

    In the starfish, spermatozoa undergo the acrosome reaction upon encountering the jelly coat of eggs. A highly sulphated glycoprotein in the jelly coat is called acrosome-reaction-inducing substance (ARIS) because it is the key signal molecule to trigger the acrosome reaction. The activity of ARIS is mainly attributed to its sulphate and saccharide residues. The extremely large molecular size and species-specific action of ARIS suggest the presence of a specific ARIS receptor on the sperm surface, but no experimental evidence for the receptor has been presented. We therefore measured specific binding of ARIS and its pronase digest (P-ARIS), which retains the full activity of ARIS, to homologous spermatozoa by using fluorescein-isothiocyanate-labelled ARIS and 125I-labelled P-ARIS, respectively. The spermatozoa had the ability to bind ARIS, as well as P-ARIS, specifically. The binding was species-specific and mostly localised to the head region of spermatozoa. Scatchard plot analysis indicated the presence of one class of ARIS receptor on the surface of acrosome-intact spermatozoa. Furthermore, the specific binding of P-ARIS to the anterior region of sperm heads was microscopically confirmed by using P-ARIS conjugated to polystyrene latex beads with intense fluorescence. It is concluded that starfish spermatozoa have a specific receptor for ARIS on the surface of the anterior region of heads. PMID:8081808

  18. Fabrication of aggregation induced emission active luminescent chitosan nanoparticles via a "one-pot" multicomponent reaction.

    PubMed

    Wan, Qing; Liu, Meiying; Xu, Dazhuang; Mao, Liucheng; Tian, Jianwen; Huang, Hongye; Gao, Peng; Deng, Fengjie; Zhang, Xiaoyong; Wei, Yen

    2016-11-01

    Chitosan based nanomaterials have been extensively examined for biomedical applications for their biodegradability, low toxicity, biological activity and low cost. In this work, a novel strategy for fabrication of luminescent polymeric nanoparticles (LPNs) based on aggregation induced emission (AIE) dye and water soluble chitosan (WS-Chitosan) were firstly developed via a highly efficient mercaptoacetic acid (MA) locking imine reaction. In this multicomponent reaction (MCR), MA serves as "lock" to connect 9,10-Bis(aldehydephenl)anthracene dye (An-CHO) and amino-containing WS-Chitosan under mild reaction conditions. The obtained WS-Chitosan@An-CHO LPNs show strong yellow emission and great water dispersibility. Biological evaluation results demonstrated that synthetic luminescent polymeric nanoparticles possess desirable cytocompatibility and distinct imaging properties. Therefore, we have developed a facile and useful method to fabricate AIE active nanoprobes with desirable properties for various biomedical applications. This strategy should be a general and easy handling tool to fabricate many other AIE dye based materials. PMID:27516264

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

    SciTech Connect

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

    2015-01-15

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

  20. Ab Initio Studies of Shock-Induced Chemical Reactions of Inter-Metallics

    NASA Astrophysics Data System (ADS)

    Zaharieva, Roussislava; Hanagud, Sathya

    2009-06-01

    Shock-induced and shock assisted chemical reactions of intermetallic mixtures are studied by many researchers, using both experimental and theoretical techniques. The theoretical studies are primarily at continuum scales. The model frameworks include mixture theories and meso-scale models of grains of porous mixtures. The reaction models vary from equilibrium thermodynamic model to several non-equilibrium thermodynamic models. The shock-effects are primarily studied using appropriate conservation equations and numerical techniques to integrate the equations. All these models require material constants from experiments and estimates of transition states. Thus, the objective of this paper is to present studies based on ab initio techniques. The ab inito studies, to date, use ab inito molecular dynamics. This paper presents a study that uses shock pressures, and associated temperatures as starting variables. Then intermetallic mixtures are modeled as slabs. The required shock stresses are created by straining the lattice. Then, ab initio binding energy calculations are used to examine the stability of the reactions. Binding energies are obtained for different strain components super imposed on uniform compression and finite temperatures. Then, vibrational frequencies and nudge elastic band techniques are used to study reactivity and transition states. Examples include Ni and Al.

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

    PubMed Central

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

    2015-01-01

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

  2. Separation of the sperm agglutinin and the acrosome reaction-inducing substance in egg jelly of starfish.

    PubMed

    Uno, Y; Hoshi, M

    1978-04-01

    The egg jelly of the starfish Asterias amurensis was separated into the fractions J1, J2, and J3 on a Sephadex G-100 column. The Jl fraction induced the acrosome reaction and J2 induced sperm agglutination. Chemical analysis and chromatography revealed that sperm agglutinin is similar to asterosaponin A. PMID:17847329

  3. 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)

  4. Acute Effects of Exposure to (56)Fe and (16)O Particles on Learning and Memory.

    PubMed

    Rabin, Bernard M; Poulose, Shibu M; Carrihill-Knoll, Kirsty L; Ramirez, Francisco; Bielinski, Donna F; Heroux, Nicholas; Shukitt-Hale, Barbara

    2015-08-01

    Although it has been shown that exposure to HZE particles disrupts cognitive performance when tested 2-4 weeks after irradiation, it has not been determined whether exposure to HZE particles acutely affects cognitive performance, i.e., within 4-48 h after exposure. The current experiments were designed to determine the acute effects of exposure to HZE particles ((16)O and (56)Fe) on cognitive performance and whether exposure to HZE particles affected learning or memory, as well as to understand the relationship between acute changes in the levels of NOX2 (a measure of oxidative stress) and COX2 (a measure of neuroinflammation) in specific brain regions and cognitive performance. The results of these studies indicate that the acute effects of radiation exposure on cognitive performance are on memory, not learning. Further, the acute effects of exposure to HZE particles on oxidative stress and neuroinflammation and their relationship to cognitive performance indicate that, although the effects of exposure to both (56)Fe and (16)O are widespread, only changes in specific regions of the brain may be related to changes in cognitive function. PMID:26207687

  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. Ab initio many-body calculations of nucleon scattering on ^16O

    NASA Astrophysics Data System (ADS)

    Navratil, Petr; Quaglioni, Sofia; Roth, Robert

    2008-10-01

    We develop a new ab initio many-body approachootnotetextS. Quaglioni and P. Navratil, arXiv:0804.1560. capable of describing simultaneously both bound and scattering states in light nuclei, by combining the resonating-group methodootnotetextY. C. Tang et al., Phys. Rep. 47, 167 (1978); K. Langanke and H. Friedrich, Advances in Nuclear Physics, Plenum, New York, 1987. with the ab initio no-core shell model (NCSM).ootnotetextP. Navratil, J. P. Vary, and B. R. Barrett, Phys. Rev. Lett. 84, 5728 (2000); Phys. Rev. C 62, 054311 (2000). In this way, we complement a microscopic-cluster technique with the use of realistic interactions, and a microscopic and consistent description of the nucleon clusters, while preserving Pauli principle and translational symmetry. We will present results for low-energy nucleon scattering on ^16O and for A=17 bound states obtained using realistic nucleon-nucleon potentials. The ^16O wave functions are calculated within the importance-truncated NCSMootnotetextR. Roth and P. Navratil, Phys. Rev. Lett. 99, 092501 (2007). that allows the use of model spaces up to 18φ and ultimately enables to reach convergence of phase-shifts and other observables. Prepared by LLNL under Contract DE-AC52-07NA27344. Support from the U.S. DOE/SC/NP (Work Proposal No. SCW0498), and from the U. S. Department of Energy Grant DE-FC02-07ER41457 is acknowledged.

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

    NASA Technical Reports Server (NTRS)

    Friend, Robert B.

    1998-01-01

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

  8. [Analysis on 315 cases of clinical adverse drug reaction/event induced by gastrodin].

    PubMed

    Zheng, Yang-yang; Dong, Zhi; Lu, Xiao-qin; Xia, Yong-peng; Zhu, Shu-bing

    2015-05-01

    With patients' general situation, medication use, occurrence time of adverse drug reaction/event (ADR/ADE), clinical manifestations and prognosis as reference items, a retrospective study was made for 315 cases with ADR/ADE induced by Gastrodin in Chongqing from January 2008 to June 2014, in order to analyze the characteristics of ADR/ADE and provide reference for rational clinical medication. The results showed that among the 315 cases with ADR/ADE, 143 cases (45.4%) were males and 172 cases (54.6%) were females, most of them (74.9%) were aged above 45; 60 cases (19.0%) with ADE were caused by off-label indications and 66 cases (21.0%) with ADE were caused by over dosage; ADR/ADE cases induced by intravenous drip mainly happened within 30 min (85.5%), ADR/ADE cases induced by oral administration mainly happened within 2 h (74.4%), and all of ADR/ ADE cases induced by intramuscular injection happened within 10 min. Totally 593 ADR/ADE cases were reported, which were mainly damages in gastrointestinal system, skin and its adnexa; And 61.9% of ADR/ADE cases were newly reported. It is suggested that medical workers shall learn about the regularity and characteristics of ADR/ADE induced by gastrodin, apply it in clinic with standards, pay close attention to changes of patients' situations and attach importance to the monitoring of ADR/ADE, so as to enhance the safety of medication. PMID:26390669

  9. 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.

  10. 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.

  11. ON THE MEASUREMENT OF THE {sup 13}C(α, n){sup 16}O S-FACTOR AT NEGATIVE ENERGIES AND ITS INFLUENCE ON THE s-PROCESS

    SciTech Connect

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

    2013-11-10

    The {sup 13}C(α, n){sup 16}O 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 ∼< 10{sup 8} K, corresponding to an energy interval where the {sup 13}C(α, n){sup 16}O 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 {sup 17}O, 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 {sup 13}C({sup 6}Li, n {sup 16}O)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 {sup 13}C(α, n){sup 16}O astrophysical factor. A larger ANC for the 6.356 MeV level is measured with respect to the ones in the literature, (C-tilde{sub α{sup 1}{sup 3}C}{sup 17O(1/2+)2} = 7.7 ± 0.3{sub stat} {sub -1.5}{sup +1.}|6 norm fm{sup –1}, yet in agreement with the preliminary result given in our preceding letter, indicating an increase of the {sup 13}C(α, n){sup 16}O reaction rate below about 8 × 10{sup 7} K if compared with the recommended values. At ∼10{sup 8} 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. Experimental elaboration of faulting induced by fluid-releasing mineral reactions in subduction zones

    NASA Astrophysics Data System (ADS)

    Green, H.; Zhang, J.; Jung, H.; Dobrzinetskaya, L.

    2003-04-01

    Dehydration embrittlement has been cited repeatedly as a potential mechanism for triggering earthquakes at depths where unassisted brittle failure is impossible due to the normal-stress-dependence of friction. We are investigating two different aspects of this problem in the laboratory: (i) dehydration of antigorite under stress where the ΔV of reaction varies from strongly positive to distinctly negative; (ii) deformation of eclogite in which the nominally anhydrous minerals contain small amounts of dissolved H_2O that can lead to faulting induced by very small amounts of melting stimulated by exsolution of H_2O. (i) Antigorite has the largest stability field of the serpentines and is often cited as potentially being the source of most or all mantle earthquakes to a depth of over 200 km. However, like other low-pressure hydrous phases, the net volume change accompanying antigorite dehydration varies from strongly positive at low P to negative at P > ˜2-2.5 GPa. Fracture mechanics theory predicts that dehydration should not induce shear failure if ΔV<0. To test the effect of ΔV on faulting, we have deformed an extensively-serpentinized peridotite at P = 1-6 GPa. We conducted constant strain rate experiments in a Griggs-type apparatus at P = 1.0 - 3.4 GPa and rapid-pumping experiments in a Walker-type multianvil apparatus, culminating in pressures as high as 6 GPa. Independent of the sign of ΔV, specimens subjected to stress during dehydration yielded extremely thin zones of reaction products with shear offset across them. Some were clearly faults whereas others could be precursors to faulting. Fluid released at grain boundaries between antigorite and relict olivine locally produced Mode I cracks &fluid inclusions. (ii) Deformation of "wet" eclogite at 3 GPa and temperatures between the wet and dry solidi induced exsolution of H_2O and formation of very small amounts (<1%) of melt, leading to faulting. At lower temperature the rock was extremely strong but

  13. 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

  14. Electron-beam-induced reactions at O 2/GaAs(1 0 0) interfaces

    NASA Astrophysics Data System (ADS)

    Palomares, F. J.; Alonso, M.; Jiménez, I.; Avila, J.; Sacedón, J. L.; Soria, F.

    2001-06-01

    We present a high resolution core-level photoemission study with synchrotron radiation, which illustrates the induced chemical reactions at O 2/GaAs(1 0 0) interfaces upon irradiation with a 150 eV electron beam, for different current densities. A detailed line shape analysis of As(3d) and Ga(3d) levels allows us to identify the oxide phases formed, and to follow their evolution up to coverages of 10 Å. Equivalent amounts of Ga and As oxides are produced. The distribution of As oxides, in particular the As 2O 3/As 2O 5 oxide ratio, is found to depend on the electronic current density, whereas no differences are observed for Ga oxides. These changes are discussed in terms of the kinetic constraints introduced by the electron beam and the instability of the As 2O 5 species upon electron bombardment in vacuum.

  15. Nucleon and triton production from nucleon-induced reactions on 7Li

    NASA Astrophysics Data System (ADS)

    Watanabe, Yukinobu; Guo, Hairui; Nagaoka, Kohei; Matsumoto, Takuma; Ogata, Kazuyuki; Yahiro, Masanobu

    2016-06-01

    Nucleon (N) and triton production from nucleon-induced reactions on 7Li at an incident energy of 14 MeV are analyzed by using three-body continuum discretized coupled channels method (CDCC), final state interaction (FSI) model, and sequential decay (SD) model. The CDCC is used to describe nucleon and triton production via breakup continuum channels, 7Li(N,N')7Li*→ t + α. Triton production from p(n) + 7Li → t + 5Li(5He) channel and nucleon production from sequential decay of the ground-state 5Li(5He) are calculated by the FSI model and the SD model, respectively. The calculated double differential cross sections for both nucleon and triton production are in good agreement with experimental ones except at relatively low nucleon emission energies.

  16. Nuclear Reaction Models Responsible for Simulation of Neutron-induced Soft Errors in Microelectronics

    SciTech Connect

    Watanabe, Y. Abe, S.

    2014-06-15

    Terrestrial neutron-induced soft errors in MOSFETs from a 65 nm down to a 25 nm design rule are analyzed by means of multi-scale Monte Carlo simulation using the PHITS-HyENEXSS code system. Nuclear reaction models implemented in PHITS code are validated by comparisons with experimental data. From the analysis of calculated soft error rates, it is clarified that secondary He and H ions provide a major impact on soft errors with decreasing critical charge. It is also found that the high energy component from 10 MeV up to several hundreds of MeV in secondary cosmic-ray neutrons has the most significant source of soft errors regardless of design rule.

  17. Noise-induced convergence of the low flow rate chaos in the Belousov-Zhabotinsky reaction

    NASA Astrophysics Data System (ADS)

    Yoshimoto, Minoru; Nakaiwa, Masaru; Akiya, Takaji; Ohmori, Takao; Yamaguchi, Tomohiko

    The effect of noise on the low flow-rate chaos in the Belousov-Zhabotinsky (BZ) reaction was studied. The chaos was simulated using the three-variable model of Györgyi and Field. Gaussian white noise was imposed on the flow-rate of the reactant solutions fed into CSTR to simulate the so-called type P noise. The range of average noise amplitudes was chosen between 0.01% and 1% related to the inverse residence time. The calculated time series were analyzed on the basis of their Fourier spectra, maximum Lyapunov exponent, Kolmogorov entropies, return maps and invariant density. We found that the noise induces partial order of the period-3-like oscillations in the low flowrate chaos.

  18. 7Li-induced reactions for fast-timing with LaBr3:Ce detectors

    NASA Astrophysics Data System (ADS)

    Mason, P. J. R.; Podolyàk, Zs.; Mǎrginean, N.; Regan, P. H.; Alexander, T.; Algora, A.; Alharbi, T.; Bowry, M.; Britton, R.; Bucurescu, D.; Bruce, A. M.; Bunce, M.; Cǎta-Danil, G.; Cǎta-Danil, I.; Cooper, N.; Deleanu, D.; Delion, D.; Filipescu, D.; Gelletly, W.; Glodariu, T.; Gheorghe, I.; Ghiťǎ, D.; Ilie, G.; Ivanova, D.; Kisyov, S.; Lalkovski, S.; Lica, R.; Liddick, S. N.; Mǎrginean, R.; Mihai, C.; Mulholland, K.; Negret, A.; Nita, C. R.; Rice, S.; Roberts, O. J.; Sava, T.; Smith, J. F.; Söderström, P.-A.; Stevenson, P. D.; Stroe, L.; Toma, S.; Townsley, C.; Werner, V.; Wilson, E.; Wood, R. T.; Zamfir, N. V.; Zhekova, M.

    2012-10-01

    7Li induced-reactions have been used with a 186W target to populate nuclei around A˜180-190 at the National Institute of Physics and Nuclear Engineering in Bucharest, Romania. An array of high-purity germanium (HPGe) and cerium-doped lanthanum bromide (LaBr3:Ce) detectors have been used to measure sub-nanosecond half-lives with fast-timing techniques. The yrast 2+ state in 190Os was measured to be t1/2 = 375(20)ps, in excellent agreement with the literature value. The previously unreported half-life of the 564-keV state in 189Ir has also been measured and a value of t1/2 = 540(100)ps ps obtained.

  19. Analysis of the Nuclear Structure of 186 Re Using Neutron-Induced Reactions

    NASA Astrophysics Data System (ADS)

    Matters, David; McClory, John; Carroll, James; Chiara, Chris; Fotiades, Nikolaos; Devlin, Matt; Nelson, Ron O.

    2015-04-01

    Evaluated nuclear structure data for 186 Re identifies the majority of spin-parity assignments as tentative, with approximate values associated with the energies of several levels and transitions. In particular, the absence of known transitions that feed the Jπ =8+ isomer motivates their discovery, which would have astrophysical implications and a potential application in the development of an isomer power source. Using the GErmanium Array for Neutron Induced Excitations (GEANIE) spectrometer at the Los Alamos Neutron Science Center (LANSCE) Weapons Neutron Research (WNR) facility, the (n,2n γ) and (n,n' γ) reactions in a 99.52% enriched 187 Re target were used to measure γ-ray excitation functions in 186 Re and 187 Re, respectively. A preliminary analysis of the data obtained from the experiment reveals several new transitions in 186 Re and 187 Re.

  20. Tungsten fragmentation in nuclear reactions induced by high-energy cosmic-ray protons

    NASA Astrophysics Data System (ADS)

    Chechenin, N. G.; Chuvilskaya, T. V.; Shirokova, A. A.; Kadmenskii, A. G.

    2015-01-01

    Tungsten fragmentation arising in nuclear reactions induced by cosmic-ray protons in space-vehicle electronics is considered. In modern technologies of integrated circuits featuring a three-dimensional layered architecture, tungsten is frequently used as a material for interlayer conducting connections. Within the preequilibrium model, tungsten-fragmentation features, including the cross sections for the elastic and inelastic scattering of protons of energy between 30 and 240 MeV; the yields of isotopes and isobars; their energy, charge, and mass distributions; and recoil energy spectra, are calculated on the basis of the TALYS and EMPIRE-II-19 codes. It is shown that tungsten fragmentation affects substantially forecasts of failures of space-vehicle electronics.

  1. Towards the role of interfacial shear in shock-induced intermetallic reactions

    NASA Astrophysics Data System (ADS)

    Collinson, Mark; Chapman, David; Williamson, David; Burchell, Mark; Eakins, Daniel

    2011-06-01

    Shock-induced intermetallic reactions have previously been shown to occur on a nanosecond timescale, within the rise time of the applied shock wave. Work in this area to date has however concentrated on continuum scale measurements, raising questions as to the processes occurring at micro and meso scales. Mass transfer due to inter-facial shear at material interfaces has been suggested as a possible explanation. We will present initial work examining the role of friction on this mass mixing process across a binary interface. This work includes plate impact experiments on an inert stainless steel - aluminum friction pair, employing spatially resolved interferometry. Results from a series of metal ball-on-angled plate impact experiments at 1-2 km/s will also be presented, supported by high-speed imaging and target recovery.

  2. Tungsten fragmentation in nuclear reactions induced by high-energy cosmic-ray protons

    SciTech Connect

    Chechenin, N. G. Chuvilskaya, T. V.; Shirokova, A. A.; Kadmenskii, A. G.

    2015-01-15

    Tungsten fragmentation arising in nuclear reactions induced by cosmic-ray protons in space-vehicle electronics is considered. In modern technologies of integrated circuits featuring a three-dimensional layered architecture, tungsten is frequently used as a material for interlayer conducting connections. Within the preequilibrium model, tungsten-fragmentation features, including the cross sections for the elastic and inelastic scattering of protons of energy between 30 and 240 MeV; the yields of isotopes and isobars; their energy, charge, and mass distributions; and recoil energy spectra, are calculated on the basis of the TALYS and EMPIRE-II-19 codes. It is shown that tungsten fragmentation affects substantially forecasts of failures of space-vehicle electronics.

  3. Light-induced point defect reactions of residual iron in crystalline silicon after aluminum gettering

    SciTech Connect

    Abdelbarey, D.; Kveder, V.; Schroeter, W.; Seibt, M.

    2010-08-15

    Deep level transient spectroscopy is used to study light-induced reactions of residual iron impurities after aluminum gettering (AlG) in crystalline silicon. White-light illumination at room temperature leads to the formation of a defect which is associated with a donor level at 0.33 eV above the valence band. This defect is stable up to about 175 deg. C where it dissociates reversibly in case of small iron concentrations and irreversibly for high iron concentrations. Since marker experiments using gold and platinum diffusion show a high vacancy concentration after AlG a tentative identification of the new defect as the metastable iron-vacancy pair is proposed.

  4. Functional properties of nisin-carbohydrate conjugates formed by radiation induced Maillard reaction

    NASA Astrophysics Data System (ADS)

    Muppalla, Shobita R.; Sonavale, Rahul; Chawla, Surinder P.; Sharma, Arun

    2012-12-01

    Nisin-carbohydrate conjugates were prepared by irradiating nisin either with glucose or dextran. Increase in browning and formation of intermediate products was observed with a concomitant decrease in free amino and reducing sugar groups indicating occurrence of the Maillard reaction catalyzed by irradiation. Nisin-carbohydrate conjugates showed a broad spectrum antibacterial activity against Gram negative bacteria (Escherichia coli, Pseudomonas fluorescence) as well as Gram positive bacteria (Staphylococcus aureus, Bacillus cereus). Results of antioxidant assays, including that of DPPH radical-scavenging activity and reducing power, showed that the nisin-dextran conjugates possessed better antioxidant potential than nisin-glucose conjugate. These results suggested that it was possible to enhance the functional properties of nisin by preparing radiation induced conjugates suitable for application in food industry.

  5. Neutron- and proton-induced reactions for analysis of bioenvironmental samples

    SciTech Connect

    Spyrou, N.M.; Altaf, W.J.; Khrbish, Y.S. )

    1988-01-01

    The study of the elemental composition of bioenvironmental samples is of continuing interest in a wide variety of medical and environmental investigations, be it as environmental monitors or as indicators of the state of health and disease of an individual or a population. Nuclear activation methods play an important role in these studies as research tools and in certain cases are employed as rapid, routine analytical techniques. Although the authors have been using instrumental neutron activation analysis as the main technique for obtaining information about elemental composition and concentration, they have also developed techniques, for further or complementary analysis, in which proton-induced reactions have been exploited. Two recent studies, in which the composition of human lung tissue and the elemental concentration in plant samples were determined, have been selected as illustrations of the techniques employed.

  6. Infrared spectroscopic studies on reaction induced conformational changes in the NADH ubiquinone oxidoreductase (complex I).

    PubMed

    Hellwig, Petra; Kriegel, Sébastien; Friedrich, Thorsten

    2016-07-01

    Redox-dependent conformational changes are currently discussed to be a crucial part of the reaction mechanism of the respiratory complex I. Specialized difference Fourier transform infrared techniques allow the detection of side-chain movements and minute secondary structure changes. For complex I, (1)H/(2)H exchange kinetics of the amide modes revealed a better accessibility of the backbone in the presence of NADH and quinone. Interestingly, the presence of phospholipids, that is crucial for the catalytic activity of the isolated enzyme complex, changes the overall conformation. When comparing complex I samples from different species, very similar electrochemically induced FTIR difference spectra and very similar rearrangements are reported. Finally, the information obtained with variants and from Zn(2+) inhibited samples for the conformational reorganization of complex I upon electron transfer are discussed in this review. This article is part of a Special Issue entitled Respiratory complex I, edited by Volker Zickermann and Ulrich Brandt. PMID:26702948

  7. Neutrino-Induced Neutral-Current Reaction Cross Sections for r-PROCESS Nuclei

    NASA Astrophysics Data System (ADS)

    Langanke, K.; Kolbe, E.

    2002-11-01

    Neutrino-induced reactions play an important role during and after the r-process, if the latter occurs in an environment with extreme neutrino fluxes such as the neutrino-driven wind model or neutron star mergers. Recently we have evaluated the charged-current neutrino-nucleus cross sections relevant for r-process simulations. We extend our approach here to the neutral-current cross sections. Our tabulation considers neutron-rich nuclei with neutron numbers N=41-135 and charge numbers Z=21-82 and lists total as well as partial neutron spallation cross sections. The calculations have been performed within the random phase approximation considering multipole transitions with J<=3 and both parities. The supernova neutrino spectrum is described by a Fermi-Dirac distribution with various temperature parameters between T=2.8 MeV and T=10 MeV and with the degeneracy parameters α=0 and α=3.

  8. Activation cross sections of proton induced nuclear reactions on gold up to 65MeV.

    PubMed

    Ditrói, F; Tárkányi, F; Takács, S; Hermanne, A

    2016-07-01

    Activation cross sections of proton induced reactions on gold for production of (197m,197g,195m,195g, 193m,193g,192)Hg, (196m,196g(cum),195g(cum),194,191(cum))Au, (191(cum))Pt and (192)Ir were measured up to 65MeV proton energy, some of them for the first time. The new data are in acceptably good agreement with the recently published earlier experimental data in the overlapping energy region. The experimental data are compared with the predictions of the TALYS 1.6 (results in TENDL-2015 on-line library) and EMPIRE 3.2 code. PMID:27156194

  9. Ion irradiation induced solid-state amorphous reaction in Ni/Ti multilayers

    NASA Astrophysics Data System (ADS)

    Milosavljević, Momir; Toprek, Dragan; Obradović, Marko; Grce, Ana; Peruško, Davor; Dražič, Goran; Kovač, Janez; Homewood, Kevin P.

    2013-03-01

    The effects of Ar ion irradiation on interfacial reactions induced in Ni/Ti multilayers were investigated. Structures consisting of 10 alternate Ni (˜26 nm) and Ti (˜20 nm) layers of a total thickness ˜230 nm were deposited by ion sputtering on Si (1 0 0) wafers. Argon irradiations were done at 180 keV, to the doses of 1-6 × 1016 ions/cm2, the samples being held at room temperature. The projected implanted ion range is 86 ± 36 nm, maximum energy loss is closer to the surface, and maximum displacements per atom (dpa) from 47 to 284 for Ni and 26 to 156 for Ti. Characterizations of samples were performed by transmission electron microscopy (TEM) and Rutherford backscattering spectrometry (RBS). It is shown that ion irradiation induced a progressed intermixing in the mostly affected zone already for the lowest dose, the thickness of the mix increasing linearly with the irradiation dose. The mixed phase is fully amorphous, starting with a higher concentration of Ni (which is the diffusing species) from the initial stages, and saturating at Ni:Ti˜66:34. A thick amorphous layer (˜127 nm) formed towards the surface region of the structure for the irradiation dose of 4 × 1016 ions/cm2 remains stable with increasing the dose to 6 × 1016 ions/cm2, which introduces up to 6-7 at.% of Ar within the mix. The results are discussed in light of the existing models. They can be interesting for introducing a selective and controlled solid-state reaction and towards further studies of ion irradiation stability of amorphous Ni-Ti phase.

  10. Ultrastructural localization of acrosome reaction-inducing substance (ARIS) on sperm of the starfish Asterias amurensis.

    PubMed

    Longo, F J; Ushiyama, A; Chiba, K; Hoshi, M

    1995-05-01

    Using colloidal gold tagged ligands we have identified the ultrastructural site of ARIS binding to intact and acrosome-reacted starfish sperm. In intact sperm, colloidal gold conjugated ARIS was specifically localized to a single domain (0.1-0.3 micron in diameter) on the plasma membrane. This site was located on the anterior-lateral aspect of the sperm head, that is, just peripheral to the region occupied by the acrosomal vesicle and periacrosomal components. When sperm were labeled with colloidal gold conjugated ARIS, washed to remove unbound label, and then induced to undergo the acrosome reaction, the labeled patch remained associated with the plasma membrane and was positioned just lateral to the acrosomal process. However, when sperm were suspended in labeled ARIS and induced to undergo the acrosome reaction, label was observed along the entire anterior aspect of the sperm head with the exception of the acrosomal process. Labeling along the entire anterior aspect of the sperm head in this case was deemed to be nonspecific and due to binding of colloidal gold tagged molecules to components formerly located within the acrosomal vesicle, as the same pattern was obtained using colloidal gold tagged bovine serum albumin. Quantitative and qualitative aspects of ARIS binding observed here by electron microscopy are in agreement with measured binding characteristics previously reported (Ushiyama et al., 1993a: Zygote 1:121-127; Ushiyama et al., 1993b: J Reprod Dev 39:53-54), and indicate that the site of labeled ARIS binding represents a specific plasma membrane domain occupied by ARIS receptors. PMID:7619512

  11. Multifragmentation in intermediate energy {sup 129}Xe-induced heavy-ion reactions

    SciTech Connect

    Tso, Kin

    1996-05-01

    The {sup 129}Xe-induced reactions on {sup nat}Cu, {sup 89}Y, {sup 165}Ho, and {sup 197}Au at bombarding energies of E/A = 40 & 60 MeV have been studied theoretically and experimentally in order to establish the underlying mechanism of multifragmentation at intermediate energy heavy-Ion collisions. Nuclear disks formed in central heavy-ion collisions, as simulated by means of Boltzmann-like kinetic equations, break up into several fragments due to a new kind of Rayleigh-like surface instability. A sheet of liquid, stable in the limit of non-interacting surfaces, is shown to become unstable due to surface-surface interactions. The onset of this instability is determined analytically. A thin bubble behaves like a sheet and is susceptible to the surface instability through the crispation mode. The Coulomb effects associated with the depletion of charges in the central cavity of nuclear bubbles are investigated. The onset of Coulomb instability is demonstrated for perturbations of the radial mode. Experimental intermediate-mass-fragment multiplicity distributions for the {sup 129}Xe-induced reactions are shown to be binomial at each transverse energy. From these distributions, independent of the specific target, an elementary binary decay probability p can be extracted that has a thermal dependence. Thus it is inferred that multifragmentation is reducible to a combination of nearly independent emission processes. If sequential decay is assumed, the increase of p with transverse energy implies a contraction of the emission time scale. The sensitivity of p to the lower Z threshold in the definition of intermediate-mass-fragments points to a physical Poisson simulations of the particle multiplicities show that the weak auto-correlation between the fragment multiplicity and the transverse energy does not distort a Poisson distribution into a binomial distribution. The effect of device efficiency on the experimental results has also been studied.

  12. Lectin staining and flow cytometry reveals female-induced sperm acrosome reaction and surface carbohydrate reorganization

    PubMed Central

    Kekäläinen, Jukka; Larma, Irma; Linden, Matthew; Evans, Jonathan P.

    2015-01-01

    All cells are covered by glycans, an individually unique layer of oligo- and polysaccharides that are critical moderators of self-recognition and other cellular-level interactions (e.g. fertilization). The functional similarity between these processes suggests that gamete surface glycans may also have an important, but currently overlooked, role in sexual selection. Here we develop a user-friendly methodological approach designed to facilitate future tests of this possibility. Our proposed method is based on flow cytometric quantification of female-induced sperm acrosome reaction and sperm surface glycan modifications in the Mediterranean mussel Mytilus galloprovincialis. In this species, as with many other taxa, eggs release water-soluble factors that attract conspecific sperm (chemoattraction) and promote potentially measurable changes in sperm behavior and physiology. We demonstrate that flow cytometry is able to identify sperm from other seawater particles as well as accurately measure both acrosome reaction and structural modifications in sperm glycans. This methodological approach can increase our understanding of chemically-moderated gamete-level interactions and individual-specific gamete recognition in Mytilus sp. and other taxa with similar, easily identifiable acrosome structure. Our approach is also likely to be applicable to several other species, since carbohydrate-mediated cellular-level interactions between gametes are universal among externally and internally fertilizing species. PMID:26470849

  13. The Modulatory Effect of Ischemia and Reperfusion on Arginine Vasopressin-Induced Arterial Reactions

    PubMed Central

    Malinowski, Bartosz; Piotrowska, Małgorzata; Grześk, Grzegorz; Gajdus, Marta

    2016-01-01

    Aim of the Study. The purpose of this study was to investigate the impact of ischemia and reperfusion on the resistance of arteries to AVP (arginine vasopressin), with a particular emphasis on the role of smooth muscle cells in the action of vasopressin receptors and the role of the cGMP-associated signalling pathway. Materials and Methods. Experiment was performed on the perfunded tail arteries from male Wistar rats. The constriction triggered by AVP after 30 minutes of ischemia and 30 and 90 minutes of reperfusion was analysed. Analogous experiments were also carried out in the presence of 8Br-cGMP. Results. Ischemia reduces and reperfusion increases in a time-dependent manner the arterial reaction to AVP. The presence of 8Br-cGMP causes a significant decrease of arterial reactivity under study conditions. Conclusions. Ischemia and reperfusion modulate arterial contraction triggered by AVP. The effect of 8Br-cGMP on reactions, induced by AVP after ischemia and reperfusion, indicates that signalling pathway associated with nitric oxide (NO) and cGMP regulates the tension of the vascular smooth muscle cells. PMID:27563664

  14. Cephalosporin Induced Disulfiram-Like Reaction: A Retrospective Review of 78 Cases

    PubMed Central

    Ren, Shiyan; Cao, Yuxia; Zhang, Xiuwei; Jiao, Shichen; Qian, Songyi; Liu, Peng

    2014-01-01

    Concomitant ingestion of alcohol and cephalosporin may cause a disulfiram-like reaction; however its fatal outcomes are not commonly known. We retrospectively reviewed 78 patients who had cephalosporin induced disulfiram-like reaction (CIDLR). The patients who had a negative skin test to cephalosporin prior to intravenous antibiotics were included, and those who were allergic to either alcohol or antibiotics were excluded. The average age of 78 patients was 37.8±12.2 (21–60) years. Of the 78 patients, 93.58% of the patients were males, 70.51% of the patients consumed alcohol after use of antibiotics, and 29.49% patients consumed alcohol initially, followed by intravenous antibiotics; however, no significant difference of morbidity was observed in these two groups. All patients were administered antibiotics intravenously. Five of 78 patients (6.41%) developed severe CIDLR too urgently to be rescued successfully. In conclusion, it is important for clinicians to educate patients that no alcohol should be used if one is taking cephalosporin. Also, clinicians should keep in mind that cephalosporin should not be prescribed for any alcoholics. PMID:24670024

  15. Electrochemical Impedance Spectroscopy (bio)sensing through hydrogen evolution reaction induced by gold nanoparticles.

    PubMed

    Mayorga-Martinez, Carmen C; Chamorro-Garcia, Alejandro; Merkoçi, Arben

    2015-05-15

    A new gold nanoparticle (AuNP) based detection strategy using Electrochemical Impedance Spectroscopy (EIS) through hydrogen evolution reaction (HER) is proposed. This EIS-HER method is used as an alternative to the conventional EIS based on [Fe(CN)6](3-/4-) or [Ru(NH3)6](3+/2+) indicators. The proposed method is based on the HER induced by AuNPs. EIS measurements for different amounts of AuNP are registered and the charge transfer resistance (Rct) was found to correlate and be useful for their quantification. Moreover the effect of AuNP size on electrical properties of AuNPs for HER using this sensitive technique has been investigated. Different EIS-HER signals generated in the presence of AuNPs of different sizes (2, 5, 10, 15, 20, and 50 nm) are observed, being the corresponding phenomena extendible to other nanoparticles and related catalytic reactions. This EIS-HER sensing technology is applied to a magneto-immunosandwich assay for the detection of a model protein (IgG) achieving improvements of the analytical performance in terms of a wide linear range (2-500 ng mL(-1)) with a good limit of detection (LOD) of 0.31 ng mL(-1) and high sensitivity. Moreover, with this methodology a reduction of one order of magnitude in the LOD for IgG detection, compared with a chroamperometric technique normally used was achieved. PMID:24953452

  16. Surfactant-induced gradients in the three-dimensional Belousov-Zhabotinsky reaction.

    PubMed

    Kupitz, Dennis; Alonso, Sergio; Bär, Markus; Hauser, Marcus J B

    2011-11-01

    Scroll waves are prominent patterns formed in three-dimensional excitable media, and they are frequently considered highly relevant for some types of cardiac arrhythmias. Experimentally, scroll wave dynamics is often studied by optical tomography in the Belousov-Zhabotinsky reaction, which produces CO(2) as an undesired product. Addition of small concentrations of a surfactant to the reaction medium is a popular method to suppress or retard CO(2) bubble formation. We show that in closed reactors even these low concentrations of surfactants are sufficient to generate vertical gradients of excitability which are due to gradients in CO(2) concentration. In reactors open to the atmosphere such gradients can be avoided. The gradients induce a twist on vertically oriented scroll waves, while a twist is absent in scroll waves in a gradient-free medium. The effects of the CO(2) gradients are reproduced by a numerical study, where we extend the Oregonator model to account for the production of CO(2) and for its advection against the direction of gravity. The numerical simulations confirm the role of solubilized CO(2) as the source of the vertical gradient of excitability in reactors closed to the atmosphere. PMID:22181487

  17. The Modulatory Effect of Ischemia and Reperfusion on Arginine Vasopressin-Induced Arterial Reactions.

    PubMed

    Szadujkis-Szadurska, Katarzyna; Malinowski, Bartosz; Piotrowska, Małgorzata; Grześk, Grzegorz; Wiciński, Michał; Gajdus, Marta

    2016-01-01

    Aim of the Study. The purpose of this study was to investigate the impact of ischemia and reperfusion on the resistance of arteries to AVP (arginine vasopressin), with a particular emphasis on the role of smooth muscle cells in the action of vasopressin receptors and the role of the cGMP-associated signalling pathway. Materials and Methods. Experiment was performed on the perfunded tail arteries from male Wistar rats. The constriction triggered by AVP after 30 minutes of ischemia and 30 and 90 minutes of reperfusion was analysed. Analogous experiments were also carried out in the presence of 8Br-cGMP. Results. Ischemia reduces and reperfusion increases in a time-dependent manner the arterial reaction to AVP. The presence of 8Br-cGMP causes a significant decrease of arterial reactivity under study conditions. Conclusions. Ischemia and reperfusion modulate arterial contraction triggered by AVP. The effect of 8Br-cGMP on reactions, induced by AVP after ischemia and reperfusion, indicates that signalling pathway associated with nitric oxide (NO) and cGMP regulates the tension of the vascular smooth muscle cells. PMID:27563664

  18. Neutrino-Induced Charged-Current Reaction Rates for r-PROCESS Nuclei

    NASA Astrophysics Data System (ADS)

    Langanke, K.; Kolbe, E.

    2001-11-01

    Neutrino-induced reactions play an important role during and after the r-process if it occurs in an environment with extreme neutrino fluxes, as in the neutrino-driven wind model or neutron star mergers. The neutrino reactions can excite the daughter nucleus above the neutron threshold, which is quite low for r-process nuclei. Thus the daughter nucleus will decay by emission of one or several neutrons. We have calculated the relevant total (νe, e-) cross sections as well as the partial neutron spallation cross sections for r-process nuclei with neutron numbers N=41-135 and proton numbers Z=21-82. The supernova neutrino spectrum is described by a Fermi-Dirac distribution with various temperature parameters between T=2.8 MeV and T=10 MeV and with the degeneracy parameters α=0 and α=3. Our calculations of the nuclear response are based on the random phase approximation and consider allowed as well as forbidden transitions.

  19. Superwettability-Induced Confined Reaction toward High-Performance Flexible Electrodes.

    PubMed

    Xiong, Weiwei; Liu, Hongliang; Zhou, Yahong; Ding, Yi; Zhang, Xiqi; Jiang, Lei

    2016-05-18

    To find a general strategy to realize confinement of the conductive layer for high-performance flexible electrodes, with improved interfacial adhesion and high conductivity, is of important scientific significance. In this work, superwettability-induced confined reaction is used to fabricate high-performance flexible Ag/polymer electrodes, showing significantly improved silver conversion efficiency and interfacial adhesion. The as-prepared flexible electrodes by superhydrophilic polymeric surface under oil are highly conductive with an order of magnitude higher than the Ag/polymer electrodes obtained from original polymeric surface. The high conductivity achieved via superhydrophilic confinement is ascribed to the fact that the superhydrophilic polymeric surface can enhance the reaction rate of silver deposition and reduce the size of silver nanoparticles to achieve the densest packing. This new approach will provide a simple method to fabricate flexible and highly conductive Ag/polymer electrodes with excellent adhesion between the conductive layer and the substrate, and can be extended to other metal/polymeric electrodes or alloy/polymeric electrodes. PMID:27115913

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

    SciTech Connect

    Talukder, Srijeeta; Chaudhury, Pinaki; Sen, Shrabani; Sharma, Rahul; Adhikari, Satrajit

    2015-10-14

    We propose a strategy of using a stochastic optimization technique, namely, simulated annealing to design optimum laser pulses (both IR and UV) to achieve greater fluxes along the two dissociating channels (O{sup 18} + O{sup 16}O{sup 16} and O{sup 16} + O{sup 16}O{sup 18}) in O{sup 16}O{sup 16}O{sup 18} molecule. We show that the integrated fluxes obtained along the targeted dissociating channel is larger with the optimized pulse than with the unoptimized one. The flux ratios are also more impressive with the optimized pulse than with the unoptimized one. We also look at the evolution contours of the wavefunctions along the two channels with time after the actions of both the IR and UV pulses and compare the profiles for unoptimized (initial) and optimized fields for better understanding the results that we achieve. We also report the pulse parameters obtained as well as the final shapes they take.

  1. Revised Production Rates for Na-22 and Mn-54 in Meteorites Using Cross Sections Measured for Neutron-induced Reactions

    NASA Technical Reports Server (NTRS)

    Sisterson, J. M.; Kim, K. J.; Reedy, R. C.

    2004-01-01

    The interactions of galactic cosmic rays (GCR) with extraterrestrial bodies produce small amounts of radionuclides and stable isotopes. The production rates of many relatively short-lived radionuclides, including 2.6-year Na-22 and 312-day Mn-54, have been measured in several meteorites collected very soon after they fell. Theoretical models used to calculate production rates for comparison with the measured values rely on input data containing good cross section measurements for all relevant reactions. Most GCR particles are protons, but secondary neutrons make most cosmogenic nuclides. Calculated production rates using only cross sections for proton-induced reactions do not agree well with measurements. One possible explanation is that the contribution to the production rate from reactions initiated by secondary neutrons produced in primary GCR interactions should be included explicitly. This, however, is difficult to do because so few of the relevant cross sections for neutron-induced reactions have been measured.

  2. Modelling and analysis of nucleon emission from deuteron-induced reactions at incident energies up to 100 MeV

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

    We have so far developed a computational code system dedicated to deuteron-induced reactions in combination with some theoretical models. In our previous works, the code system was successfully applied to systematic analyses of double-differential cross sections (DDXs) of (d,xp) reactions for 12C, 27Al, and 58Ni at incident energies up to 100 MeV. In the present work, we apply the code system to neutron emission from deuteron-induced reactions. Since there is few experimental data of DDXs of (d,xn) reactions, double-differential thick target neutron yields (TTNYs) are calculated and compared with experimental data instead of DDXs. The calculation using the code system reproduces the measured TTNYs for carbon at incident energies up to 50 MeV.

  3. Ab-Initio Coupled-Cluster Study of {sup 16}O

    SciTech Connect

    Wloch, M.; Gour, J.R.; Kowalski, K.; Piecuch, P.; Dean, D.J.; Hjorth-Jensen, M.; Papenbrock, T.

    2005-06-03

    We report converged results for the ground and excited states and matter density of {sup 16}O using realistic two-body nucleon-nucleon interactions and coupled-cluster methods and algorithms developed in quantum chemistry. Most of the binding is obtained with the coupled-cluster singles and doubles approach. Additional binding due to three-body clusters (triples) is minimal. The coupled-cluster method with singles and doubles provides a good description of the matter density, charge radius, charge form factor, and excited states of a one-particle, one-hole nature, but it cannot describe the first-excited 0{sup +} state. Incorporation of triples has no effect on the latter finding.

  4. The muon capture in {sup 16}O: the angular and polarization correlations

    SciTech Connect

    Karpeshin, F. F.; Isakov, V. I.

    2012-02-15

    Longitudinal polarization of the daughter nuclei {sup 16}N which arises in Micro-Sign {sup -} capture on {sup 16}O as a function of the recoil angle, together with the angular distribution and the alignment of the recoil nucleus are calculated. The neutrinos born escape mainly along the muon spin. The polarization is found to vary from zero (recoil momentum counter to the muon spin direction) up to 50% (along the muon spin direction). The results can be applied to the experimental tests of T conservation, to the analysis of the projects of constructing the powerful mono-energetic neutrino sources, to the experimental study of the pseudo-scalar form factor and the K-electron capture, and to other spin-polarization correlation experiments.

  5. Transverse energy distribution, charged particle multiplicities and spectra in /sup 16/O-nucleus collisions

    SciTech Connect

    Sunier, J.W.

    1987-01-01

    The HELIOS (High Energy Lepton and Ion Spectrometer) experiment, installed at the CERN Super Proton Synchrotron, proposes to examine in details the physical properties of a state of high energy created in nuclei by ultra-relativistic nucleus-nucleus collisions. It is generally believed that, at high densities or temperatures, a phase transition to a plasma of quark and gluons will occur. The dynamic of the expansion of such a plasma and its subsequent condensation into a hadron gas should markedly affect the composition and momentum distribution of the emerging particles and photons. The HELIOS experimental setup therefore combines 4..pi.. calorimetric coverage with measurements of inclusive particle spectra, two particle correlations, low and high mass lepton pairs and photons. The emphasis is placed on transverse energy flow (E/sub T/) measurements with good energy resolution, and the ability to trigger the acquisition of data in a variety of E/sub T/ ranges, thereby selecting the impact parameter or the violence of the collisions. This short note presents HELIOS results, for the most part still preliminary, on /sup 16/O-nucleus collisions at the incident energies of 60 and 200 GeV per nucleon. The E/sub T/ distributions from Al, Ag and W targets are discussed and compared to the associated charged particle multiplicities from W. Charged particle and (converted) photon spectra measured with the external magnetic spectrometer are compared for /sup 16/O + W and p + W collisions at 200 GeV per nucleon. 5 refs., 7 figs.

  6. Investigations of nuclear structure and nuclear reactions induced by complex projectiles

    SciTech Connect

    Sarantites, D.G.

    1990-01-01

    This report discusses research in the following areas: nuclear structure; fusion reactions near and below the barrier; incomplete fusion and fragmentation reactions; and instrumentation and analysis. (LSP).

  7. Stirring-induced bifurcation driven by the chaotic regime in the Belousov—Zhabotinsky reaction in a CSTR

    NASA Astrophysics Data System (ADS)

    Strizhak, Peter E.

    1995-09-01

    The stirring-induced bifurcation at low stirring rate S 0 = 23 rpm of the reaction volume has been observed for the chaotic regime in the Belousov—Zhabotinsky oscillating chemical reaction (malonic acidbromatecerium(III)sulfuric acid) in a continuously stirred tank reactor in premixing mode. This bifurcation is characterized by a stepwise growth of the macroscopic spatial concentration gradients that is shown by the use of the time dependencies of the potential difference between two platinum electrodes.

  8. Fluorescence observations of LDEF exposed materials as an indicator of induced material reactions

    NASA Technical Reports Server (NTRS)

    Linton, Roger C.; Whitaker, Ann F.; Kamenetzky, Rachel R.

    1993-01-01

    Observations and measurements of induced changes in the fluorescent emission of materials exposed to the space environment on the Long Duration Exposure Facility (LDEF) have revealed systematic patterns of material-dependent behavior. These results have been supplemented by inspection of similar materials exposed on previous Space Shuttle Missions and in laboratory testing. The space environmental factors affecting the fluorescence of exposed materials have been found to include (but are not necessarily limited to) solar ultraviolet (UV) radiation, atomic oxygen (AO), thermal vacuum exposure, and synergistic combinations of these factors. Observed changes in material fluorescent behavior include stimulation, quenching, and spectral band shifts of emission. For example, the intrinsic yellow fluorescence of zinc oxide pigmented thermal control coatings undergoes quenching as a result of exposure, while coloration is stimulated in the fluorescent emission of several polyurethane coating materials. The changes in fluorescent behavior of these materials are shown to be a revealing indicator of induced material reactions as a result of space environmental exposure.

  9. Influence of surface acoustic waves induced acoustic streaming on the kinetics of electrochemical reactions

    NASA Astrophysics Data System (ADS)

    Tietze, Sabrina; Schlemmer, Josefine; Lindner, Gerhard

    2013-12-01

    The kinetics of electrochemical reactions is controlled by diffusion processes of charge carriers across a boundary layer between the electrode and the electrolyte, which result in a shielding of the electric field inside the electrolyte and a concentration gradient across this boundary layer. In accumulators the diffusion rate determines the rather long time needed for charging, which is a major drawback for electric mobility. This diffusion boundary can be removed by acoustic streaming in the electrolyte induced by surface acoustic waves propagating of the electrode, which results in an increase of the charging current and thus in a reduction of the time needed for charging. For a quantitative study of the influence of acoustic streaming on the charge transport an electropolishing cell with vertically oriented copper electrodes and diluted H3PO4-Propanol electrolytes were used. Lamb waves with various excitation frequencies were exited on the anode with different piezoelectric transducers, which induced acoustic streaming in the overlaying electrolytic liquid. An increase of the polishing current of up to approximately 100 % has been obtained with such a set-up.

  10. Time-resolved chemiluminescence study of the TiO2 photocatalytic reaction and its induced active oxygen species.

    PubMed

    Min, Lingyue; Wu, Xing-Zheng; Tetsuya, Shimada; Inoue, Haruo

    2007-01-01

    The time-resolved chemiluminescence (CL) method has been applied to study the TiO(2) photocatalytic reaction on a micros-ms timescale. The experimental set-up for time-resolved CL was improved for confirmation of the unique luminol CL induced by the photocatalytic reaction. The third harmonic light (355 nm) from an Nd:YAG laser was used for the light source of the TiO(2) photocatalytic reaction. Luminol CL induced by this reaction was detected by a photomultiplier tube (PMT) and a preamplifier was used for amplifying the CL signal. Experimental conditions affecting the photocatalytically induced CL were discussed in detail. The involvement of active oxygen species such as .OH, O(2) (.-) and H(2)O(2) in the CL was examined by adding their scavengers. It is concluded that .OH was greatly involved in the CL on a micros-ms timescale, especially in time periods <100 micros after illumination of the pulse laser. On the other hand, CL generated by O(2) (.-) began to increase after 100 micros and became dominant after 2.5 ms. A small part of the CL might be generated by H(2)O(2) on the whole micros-ms timescale. A CL reaction mechanism related with .OH and dissolved oxygen was proposed to explain the photocatalytically induced luminol CL on a micros-ms timescale, especially in periods <100 micros. PMID:17089368

  11. Use of laser spectroscopy to measure the 13C/12C and 18O/16O compositions of carbonate minerals.

    PubMed

    Barker, Shaun L L; Dipple, Gregory M; Dong, Feng; Baer, Douglas S

    2011-03-15

    The stable carbon and oxygen isotope compositions of carbonate minerals are utilized throughout the earth and environmental sciences for various purposes. Here, we demonstrate the first application of a prototype instrument, based on off-axis integrated cavity output laser spectroscopy, to measure the carbon and oxygen isotope composition of CO(2) gas evolved from the acidification of carbonate minerals. The carbon and oxygen isotope ratios were recorded from absorption spectra of (12)C(16)O(16)O, (13)C(16)O(16)O, and (12)C(16)O(18)O in the near-infrared wavelength region. The instrument was calibrated using CaCO(3) minerals with known δ(13)C(VPDB) and δ(18)O(VSMOW) values, which had been previously calibrated by isotope ratio mass spectrometry relative to the international isotopic standards NBS 18 and NBS 19. Individual analyses are demonstrated to have internal precision (1 SE) of better than 0.15‰ for δ(13)C and 0.6‰ for δ(18)O. Analysis of four carbonate standards of known isotopic composition over 2 months, determined using the original instrumental calibration, indicates that analyses are accurate to better than 0.5‰ for both δ(13)C and δ(18)O without application of standard-sample-standard corrections. PMID:21341717

  12. Analysis of the adverse reactions induced by natural product-derived drugs

    PubMed Central

    Zeng, Zhi-Ping; Jiang, Jian-Guo

    2010-01-01

    Compared with the therapeutic effects of established medicinal drugs, it is often considered that natural product-derived drugs are of a more benign nature in side-effects, which has made natural medicines become a popular form of therapy. Traditional Chinese medicine (TCM) is generally considered as being natural and harmless. TCM has been paid much more attention than before and widely used for the treatment nowadays. However, with the increasing cases of adverse drug reactions (ADRs), the ADRs induced by TCM are becoming more widely recognized. Some ADRs are sometimes even life-threatening. This article reviews literatures on ADRs induced by TCM which was published in the past 10 years. A total of 3122 cases including complete data are selected for the present analysis. From the data of the 3122 cases, statistics is carried out to the distribution of administration routes and time of the occurrence of ADRs, the prognosis of ADRs, sex and age factors, types and clinical symptoms of ADRs, and drugs involved in ADRs. In addition, occurrence and influencing factors of TCM-induced diseases are also analysed, which includes spices confusion, processing drugs improperly, toxic components, long-term medication, improper concerted application, interaction of TCM and Western medicine. It is concluded that the efficacy and toxicity of TCM, often using the compound prescription involving various plants and animals, resulted from a variety of chemical constituents, which lead to a comprehensive response in the human body. The ‘toxicity’ of TCM should be correctly recognized and reasonably utilized. PMID:20233209

  13. A biomolecule-compatible visible-light-induced azide reduction from a DNA-encoded reaction-discovery system

    NASA Astrophysics Data System (ADS)

    Chen, Yiyun; Kamlet, Adam S.; Steinman, Jonathan B.; Liu, David R.

    2011-02-01

    Using a system that accelerates the serendipitous discovery of new reactions by evaluating hundreds of DNA-encoded substrate combinations in a single experiment, we explored a broad range of reaction conditions for new bond-forming reactions. We discovered reactivity that led to a biomolecule-compatible, Ru(II)-catalysed azide-reduction reaction induced by visible light. In contrast to current azide-reduction methods, this reaction is highly chemoselective and is compatible with alcohols, phenols, acids, alkenes, alkynes, aldehydes, alkyl halides, alkyl mesylates and disulfides. The remarkable functional group compatibility and mild conditions of the reaction enabled the azide reduction of nucleic acid and oligosaccharide substrates, with no detectable occurrence of side reactions. The reaction was also performed in the presence of a protein enzyme without the loss of enzymatic activity, in contrast to two commonly used azide-reduction methods. The visible-light dependence of this reaction provides a means of photouncaging functional groups, such as amines and carboxylates, on biological macromolecules without using ultraviolet irradiation.

  14. Structure of the main saccharide chain in the acrosome reaction-inducing substance of the starfish, Asterias amurensis.

    PubMed

    Koyota, S; Wimalasiri, K M; Hoshi, M

    1997-04-18

    The structure of the main saccharide chain of the acrosome reaction-inducing substance in the egg jelly coat of the starfish, Asterias amurensis, is composed of the following pentasaccharide repeating units (Structure I). A polymer consisting of 10-11 repeating units has been observed to induce the acrosome reaction in starfish sperm at high calcium concentrations. [STRUCTURE I:see text] The identities and linkage positions of constituent sugars were established using sugar, methylation, and sulfate analyses together with one- and two-dimensional nmr spectroscopy. The structure was supported by the data obtained for desulfation products and the Smith degradation of the polysaccharide. PMID:9099675

  15. Cross Sections for Neutron-induced Reactions on Actinide Targets Extracted from Surrogate Experiments: A Status Report

    SciTech Connect

    Escher, J E; Burke, J T; Dietrich, F S; Lesher, S R; Scielzo, N D; Thompson, I J; Younes, W

    2009-10-01

    The Surrogate nuclear reactions method, an indirect approach for determining cross sections for compound-nuclear reactions involving difficult-to-measure targets, is reviewed. Focusing on cross sections for neutron-induced reactions on actinides, we review the successes of past and present applications of the method and assess its uncertainties and limitations. The approximations used in the analyses of most experiments work reasonably well for (n,f) cross sections for neutron energies above 1-2 MeV, but lead to discrepancies for low-energy (n,f) reactions, as well as for (n,{gamma}) applications. Correcting for some of the effects neglected in the approximate analyses leads to improved (n,f) results. We outline steps that will further improve the accuracy and reliability of the Surrogate method and extend its applicability to reactions that cannot be approached with the present implementation of the method.

  16. A case of hydrocortisone desensitization in a patient with radiocontrast-induced anaphylactoid reaction and corticosteroid allergy.

    PubMed

    Lee-Wong, Mary; McClelland, Suzanne; Chong, Kaman; Fernandez-Perez, Evans R; Fernandez, Evans

    2006-01-01

    Allergic reactions and systemic desensitization to corticosteroids have been documented rarely in English language literature. These reactions appear more often when the agent is applied topically and may lead to dangerous complications in patients if administered i.v. Therefore, the safety and efficacy of using an i.v. corticosteroid for desensitization in a patient who has a history of allergy to corticosteroid must be weighed carefully, especially when the aim of its use is to prevent an allergic reaction from a second drug. We report a case of successful systemic hydrocortisone desensitization in a patient with radiocontrast-induced anaphylactoid reaction and corticosteroid allergy. Sensitization to corticosteroids was determined through skin testing. The patient was desensitized to hydrocortisone and premedicated with hydrocortisone and diphenhydramine and subsequently underwent cardiac catheterization with radiocontrast without adverse reaction. PMID:16913271

  17. Electron screening effects in (p,α) reactions induced on boron isotopes studied via the Trojan Horse Method

    NASA Astrophysics Data System (ADS)

    Lamia, L.; Spitaleri, C.; Carlin, N.; Cherubini, S.; Gameiro Munhoz, M.; Gimenez Del Santo, M.; Gulino, M.; Kiss, G. G.; Kroha, V.; Kubono, S.; La Cognata, M.; Li, C.; Mukhamedzhanov, A.; Pizzone, R. G.; Puglia, S. M. R.; Wen, Qungang; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Somorjai, E.; Souza, F. A.; Szanto de Toledo, A.; Tumino, A.; Wakabayashi, Y.; Yamaguchi, H.

    2013-04-01

    The Trojan Horse Method is a powerful indirect technique allowing one to measure the bare nucleus S(E)-factor and the electron screening potential for astrophysically relevant reactions without the needs of extrapolations. The case of the (p,α) reactions induced on the two boron isotopes 10,11B is here discussed in view of the recent Trojan Horse (TH) applications to the quasi-free 10,11B+2H reactions. The comparison between the TH and the low-energy direct data allowed us to determine the electron screening potential for the 11B(p,α) reaction, while preliminary results on the 10B(p,α) reaction have been extracted.

  18. The role of thermal excitation in the tunneling-electron-induced reaction: Dissociation of dimethyl disulfide on Cu(111)

    NASA Astrophysics Data System (ADS)

    Motobayashi, Kenta; Kim, Yousoo; Ohara, Michiaki; Ueba, Hiromu; Kawai, Maki

    2016-01-01

    We found a thermally assisted increase in anharmonic coupling between the reaction coordinate and Csbnd H(D) stretch mode for the dissociation of a single dimethyl disulfide molecule on Cu(111) induced by inelastic tunneling electrons from a tip of scanning tunneling microscope (STM). The reaction order, i.e. the number of electrons required for a reaction, changes from two to one at elevated temperature while the Csbnd H(D) stretch mode is excited by tunneling electrons. The detailed reaction mechanism is studied through the quantitative analysis of the non-integer reaction order observed at intermediate temperature, where low energy vibrational mode originated from the hybridized state of molecule and substrate plays a key role.

  19. Comparative analysis of properties of channels of deuteron and tritium production in 16O p collisions at a projectile momentum of 3.25 GeV/ c per nucleon

    NASA Astrophysics Data System (ADS)

    Olimov, K.; Glagolev, V. V.; Gulamov, K. G.; Kurbanov, A.; Lutpullaev, S. L.; Olimov, A. K.; Petrov, V. I.; Yuldashev, A. A.

    2014-12-01

    The results of a comparative analysis of channels involving the inclusive production of deuterons and tritons in 16O p collisions at a projectile momentum of 3.25 GeV/ c per nucleon are presented. The mechanisms governing proton, deuteron, and triton production in the fragmentation of oxygen nuclei are found to be independent. It is shown that the observed proton-multiplicity correlations are associated predominantly with the character of the primary event of a proton-nucleon collision in 16O p interactions. It is found that, in reactions involving triton production, the contributions of processes leading to an increase in the mean proton multiplicity ( n → p + π - and np → pn) and processes leading to its decrease ( p → n + π +) compensate each other.

  20. 34S/32S and 18O/16O ratios of dissolved sulfate from interstitial water samples above gas hydrate bearing sediments of IODP Expedition 311, Cascadia

    NASA Astrophysics Data System (ADS)

    Wortmann, U. G.; Chernyavsky, B. M.; Torres, M. E.; Kastner, M.

    2008-12-01

    Microbially mediated sulfate reduction affects the isotopic composition of dissolved and solid sulfur species in marine sediments. Although several details of the fractionation process remain controversial, the overall process is well understood and can be described as the sum of several mass dependent fractionations during the stepwise reduction of sulfate to sulfide. Experiments and field data show that the 18O/16O of sulfate is also modified in the presence of sulfate-reducing microorganisms. Here we use a reaction transport model to analyze these processes and to constrain the rates of organotrophic versus methanotrophic sulfate reduction. Our results show that even in cases where sulfate concentrations decline in a linear fashion, up to 50% of all sulfate is consumed by organotrophic sulfate reduction.

  1. Silicate-metal reaction-induced snow atop the Earth's core

    NASA Astrophysics Data System (ADS)

    Hernlund, J. W.; Labrosse, S.; Houser, C. T.; Hirose, K.; Caracas, R.

    2012-12-01

    Recent experiments and thermodynamical models indicate that typical iron-bearing rocks at the Earth's core-mantle boundary (CMB) should readily react with outer core fluid to produce a layer more enriched in light elements (primarily oxygen, and possibly silicon) than the freely convecting fluid at depth which comprises the bulk of Earth's outer core. If the metallic reaction products are fluid, the resultant density anomaly atop the core is expected to be many orders of magnitude larger (on the order of a percent) than the density fluctuations driving core convection at depth (order 10 ppb), thus a gravitational stratification atop the core is inevitable if these experimental inferences are robust. On the other hand, early work by Knittle and Jeanloz on CMB reactions suggested that such reaction products could instead be solid, giving rise to an accumulation of FeO and FeSi sediments at the CMB. Buffett et al. (Science, 2000) offered a model in which FeO and/or FeSi sediments crystallize from the ambient outer core to form an electrically conducting layer at the CMB, which could help explain decadal variations in length of day. However, new constraints on the phase diagram in systems like Fe-FeO indicate that the average outer core is on the Fe-side of the eutectic, with a eutectic temperature much smaller than plausible at the CMB, which implies that such a model is impossible. Assuming that the basic experimental constraints are robust, I will argue that: 1) CMB reactions in the hotter early Earth led to the formation of a buoyant fluid layer atop the core enriched in oxygen, and 2) this enrichment in oxygen allows for crystallization on the FeO side of the eutectic at later times in Earth's evolution following sufficient secular cooling. The "snow" that crystallizes in the stratified layer can either rise and compact onto the CMB or sink and melt at depth depending upon the degree of light alloy enrichment induced by CMB reactions, and in either case will

  2. Identification of risk factors for carbamazepine-induced serious mucocutaneous adverse reactions: A case-control study using data from spontaneous adverse drug reaction reports

    PubMed Central

    Bertulyte, Ilma; Schwan, Sofie; Hallberg, Pär

    2014-01-01

    Objectives: To identify risk factors other than genetic for severe carbamazepine-induced mucocutaneous reactions, that is, SJS, TEN, and exfoliative dermatitis (ED). Materials and Methods: We did a case-control study using data from the Swedish national database of spontaneously reported adverse drug reactions (ADRs). We selected all patients who had been reported from January 1, 1965 to March 31, 2010 as having experienced SJS (n = 78), TEN (n = 6), or ED (n = 8), and assessed as at least possibly related to carbamazepine. We also included diagnoses possibly representative of early signs of these serious conditions, that is, erythema multiforme (EM, n = 34) and scaly rash (n = 13). We compared data on demographics, drug treatment, and clinical features for these patients (cases, n = 139) with those from patients who had experienced any other type of ADR from carbamazepine during the same time period (controls, n = 887). Results: After adjustment for multiple comparisons, alcohol abuse was statistically significantly more common among cases than controls (34.5% vs 8.7%, odds ratio 5.5 [95% confidence interval 3.6-8.4], P = 3.14 × 10-14 ). The same was seen for SJS and EM individually. Conclusion: Alcohol abuse is a possible risk factor for serious carbamazepine-induced mucocutaneous reactions. PMID:24799813

  3. Spectroscopic characterization of the first singlet (Ã 1B1) excited state of 7Li16O7Li

    NASA Astrophysics Data System (ADS)

    Bellert, D.; Winn, D. K.; Breckenridge, W. H.

    2003-11-01

    Using laser induced fluorescence (LIF) and resonance enhanced two-photon ionization (R2PI) spectroscopy, several (ν1',ν2',ν3') vibrational bands of the à 1B1(K'=1)←X˜ 1Σg+(0,0,0) perpendicular transition of the 7Li16O7Li molecule have been rotationally resolved and analyzed to yield effective A',B',C' values. The estimated geometry of the à 1B1 state does not vary with ν1' (symmetric stretch mode), but θ' increases and R' decreases slightly as ν2' (bending mode) increases. Extrapolation leads to an estimate for the (0,0,0) state of θ0'=105±5°, R0'=1.86±0.04 Å, and for the potential minimum θe'=102±5°, Re'=1.87±0.04 Å. The strongly bent nature of the à 1B1 state is due to promotion of an O-2 p-electron (b1) from the strongly ionic, linear Li+O-2Li+ ground state to an a1 molecular orbital which has Li/Li bonding character. The Ã1B1 state thus has an approximately Li+1/2O-1Li+1/2 charge distribution, so that the ionic bonding is less strong than in the linear ground state, where (from this study and an earlier stimulation-emission pumping study) R0″=1.611±0.003 Å. In fact, the Li-Li distance in the à 1B1 state, ˜3.0 Å, is quite similar to that of the Li2+1 ion, so the bonding may be described as that of Li2+1 bound ionically to the O-1 ion.

  4. Resonant structures in heavy-ion reactions

    SciTech Connect

    Sanders, S.J.; Henning, W.; Ernst, H.; Geesaman, D.F.; Jachcinski, C.; Kovar, D.G.; Paul, M.; Schiffer, J.P.

    1980-01-01

    An investigation of heavy-ion resonance structures using the /sup 24/Mg(/sup 16/O, /sup 12/C)/sup 28/Si reaction is presented. The data are analyzed in the context of Breit-Wigner resonances added to a direct-reaction background.

  5. Ginger for Prevention of Antituberculosis-induced Gastrointestinal Adverse Reactions Including Hepatotoxicity: A Randomized Pilot Clinical Trial.

    PubMed

    Emrani, Zahra; Shojaei, Esphandiar; Khalili, Hossein

    2016-06-01

    In this study, the potential benefits of ginger in preventing antituberculosis drug-induced gastrointestinal adverse reactions including hepatotoxicity have been evaluated in patients with tuberculosis. Patients in the ginger and placebo groups (30 patients in each group) received either 500 mg ginger (Zintoma)(®) or placebo one-half hour before each daily dose of antituberculosis drugs for 4 weeks. Patients' gastrointestinal complaints (nausea, vomiting, dyspepsia, and abdominal pain) and antituberculosis drug-induced hepatotoxicity were recorded during the study period. In this cohort, nausea was the most common antituberculosis drug-induced gastrointestinal adverse reactions. Forty eight (80%) patients experienced nausea. Nausea was more common in the placebo than the ginger group [27 (90%) vs 21 (70%), respectively, p = 0.05]. During the study period, 16 (26.7%) patients experienced antituberculosis drug-induced hepatotoxicity. Patients in the ginger group experienced less, but not statistically significant, antituberculosis drug-induced hepatotoxicity than the placebo group (16.7% vs 36.7%, respectively, p = 0.07). In conclusion, ginger may be a potential option for prevention of antituberculosis drug-induced gastrointestinal adverse reactions including hepatotoxicity. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26948519

  6. Characterization of the sperm receptor for acrosome reaction-inducing substance of the starfish, Asterias amurensis.

    PubMed

    Kawamura, Mayu; Matsumoto, Midori; Hoshi, Motonori

    2002-04-01

    Acrosome reaction-inducing substance (ARIS) in the jelly coat of starfish eggs is a highly sulfated proteoglycan-like molecule of an apparent molecular size over 10(4) kDa and plays a pivotal role in the induction of acrosome reaction in homologous spermatozoa. It is known in Asterias amurensis that ARIS binds to a restricted area of the anterior portion of sperm head, and that a glycan fragment of ARIS, named Fragment 1, consisting of 10 repeats or so of a pentasaccharide unit retains the biological activity of ARIS to an appreciable extent. In this report, we have shown the binding of Fragment 1, a relatively small pure glycan fragment of ARIS, to the putative ARIS receptor on the sperm surface by three independent methods. First, the specific binding of P-ARIS to isolated sperm membranes was monitored in real-time by using a surface plasmon resonance detector, namely a Biacore sensor system. The specific and quantitative binding of Fragment 1 to the intact sperm and to isolated sperm membranes was similarly monitored. Secondly, the binding of 125I-labeled Fragment 1 to the intact sperm was stoichiometrically measured, for which we had developed a unique procedure for radioiodination of saccharide chains. It is found that Fragment 1 competes with P-ARIS for the binding to ARIS-receptor, suggesting that Fragment 1 is a useful ligand in the search for ARIS receptor protein(s). Thirdly, the putative receptor molecules were specifically labeled by using Fragment 1 as a ligand for photoaffinity crosslink technique. Taking these results into account, we conclude that starfish sperm have the ARIS receptor, which consists most probably of 50 to 60 kDa proteins, of reasonably high affinity (for Fragment 1, Kd = 15 microM, Bmax = 8.4 x 10(4) per cell). PMID:12130821

  7. Piezoelectrochemical effect: Mechanical energy induced redox reaction in aqueous solutions through vibrating piezoelectric materials

    NASA Astrophysics Data System (ADS)

    Hong, Kuang-Sheng

    We propose a phenomenon of piezoelectrochemical (PZEC) effect for the direct conversion of mechanical energy to chemical energy. This phenomenon is further applied for generating hydrogen and oxygen via direct water decomposition by means of as-synthesized piezoelectric quartz (SiO2) nano-rods, ZnO microfibers, and BaTiO3 microdendrites. The materials are vibrated with ultrasonic waves leading to a strain-induced electric charge development on their surface. With sufficient electric potential, the strained piezoelectric materials in water triggered the redox reaction of water to produce hydrogen and oxygen gases. All materials have indicated a well response to the external mechanical vibration to drive the desired chemical reactions. ZnO fibers under ultrasonic vibrations showed a stoichiometric ratio of H 2/O2 (2:1) initial gas production from pure water. The efficiency of the piezoelectrochemical effect was calculated by ratio of the chemical energy output over the mechanical energy input of the system. The study of piezoelectrochemical effect is further applied to the environmental cleaning technology. Accordingly, a dissolved orange dye (AO7) was decomposed via mechanical driving force by using BaTiO3 microdendrites. Kinetic details of the dye decomposition through piezoelectrochemical effect were investigated. In addition, the piezoelectrochemical effect was proposed to the implication of tectonic hydrogen in geological systems providing insights of hydrogen generation in active fault zones. The tectonic hydrogen produced through PZEC effect could be a sustainable energy source for subsurface microbial community. This study provides a simple and cost-effective technology for generating hydrogen fuels as well as environmental cleaning by scavenging energy wastes such as noise or stray vibrations from the environment. This new piezoelectrochemical effect may have potential implications in solving the challenging energy and environmental issues that we are facing

  8. Photo-induced hydrogen exchange reaction between methanol and glyoxal: formation of hydroxyketene.

    PubMed

    Mielke, Zofia; Mucha, Małgorzata; Bil, Andrzej; Golec, Barbara; Coussan, Stephane; Roubin, Pascale

    2008-08-25

    We study the structure and photochemistry of the glyoxal-methanol system (G-MeOH) by means of FTIR matrix isolation spectroscopy and ab initio calculations. The FTIR spectra show that the non-hydrogen-bonded complex, G-MeOH-1, is present in an inert environment of solid argon. MP2/aug-cc-pVDZ calculations indicate that G-MeOH-1 is the most stable complex among the five optimized structures. The interaction energy partitioned according to the symmetry-adapted perturbation theory (SAPT) scheme demonstrates that the dispersion energy gives a larger contribution to the stabilization of a non-hydrogen-bonded G-MeOH-1 complex than compared to the hydrogen-bonded ones. The irradiation of G-MeOH-1 with the filtered output of a mercury lamp (lambda>370 nm) leads to its photo-conversion into the hydroxyketene-methanol complex HK-MeOH-1. The identity of HK-MeOH-1 is confirmed by both FTIR spectroscopy and MP2/aug-cc-pVDZ calculations. An experiment with deuterated methanol (CH(3)OD) evidences that hydroxyketene is formed in a photo-induced hydrogen exchange reaction between glyoxal and methanol. The pathway for the photo-conversion of G-MeOH-1 to HK-MeOH-1 is studied by a coupled-cluster method [CR-CC(2,3)]. The calculations confirm our experimental findings that the reaction proceeds via hydrogen atom exchange between the OH group of methanol and CH group of glyoxal. PMID:18613199

  9. A new mathematical model to simulate AVA cold-induced vasodilation reaction to local cooling

    NASA Astrophysics Data System (ADS)

    Rida, Mohamad; Karaki, Wafaa; Ghaddar, Nesreen; Ghali, Kamel; Hoballah, Jamal

    2014-01-01

    The purpose of this work was to integrate a new mathematical model with a bioheat model, based on physiology and first principles, to predict thermoregulatory arterio-venous anastomoses (AVA) and cold-induced vasodilation (CIVD) reaction to local cooling. The transient energy balance equations of body segments constrained by thermoregulatory controls were solved numerically to predict segmental core and skin temperatures, and arterial blood flow for given metabolic rate and environmental conditions. Two similar AVA-CIVD mechanisms were incorporated. The first was activated during drop in local skin temperature (<32 °C). The second mechanism was activated at a minimum finger skin temperature, T CIVD, min, where the AVA flow is dilated and constricted once the skin temperature reached a maximum value. The value of T CIVD,min was determined empirically from values reported in literature for hand immersions in cold fluid. When compared with published data, the model predicted accurately the onset time of CIVD at 25 min and T CIVD,min at 10 °C for hand exposure to still air at 0 °C. Good agreement was also obtained between predicted finger skin temperature and experimentally published values for repeated immersion in cold water at environmental conditions of 30, 25, and 20 °C. The CIVD thermal response was found related to core body temperature, finger skin temperature, and initial finger sensible heat loss rate upon exposure to cold fluid. The model captured central and local stimulations of the CIVD and accommodated observed variability reported in literature of onset time of CIVD reaction and T CIVD,min.

  10. Investigations of nuclear structure and nuclear reactions induced by complex projectiles. Progress report for the period September 1, 1992--August 31, 1993

    SciTech Connect

    Sarantites, D.G.

    1993-09-06

    This is a progress report on activities of the Washington University group in nuclear reaction studies for the period Sept 1, 1992 to Aug 31, 1993. This group has a research program which touches five areas of nuclear physics: nuclear structure studies at high spin; studies at the interface between structure and reactions; production and study of hot nuclei; reaction mechanism studies; development and use of novel techniques and instrumentation in the above areas of research. Specific activities of the group include in part: superdeformation in {sup 82}Sr; structure of and identical bands in {sup 182}Hg and {sup 178}Pt; a highly deformed band in {sup 136}Pm; particle decay of the {sup 164}Yb compound nucleus; fusion reactions; proton evaporation; two-proton decay of {sup 12}O; modeling and theoretical studies; excited {sup 16}O disassembly into four alpha particles; {sup 209}Bi + {sup 136}Xe collisions at 28.2 MeV/amu; and development work on 4{pi} solid angle gamma detectors, and x-ray detectors.

  11. Severe inflammatory reaction induced by peritoneal trauma is the key driving mechanism of postoperative adhesion formation

    PubMed Central

    2011-01-01

    Background Many factors have been put forward as a driving mechanism of surgery-triggered adhesion formation (AF). In this study, we underline the key role of specific surgical trauma related with open surgery (OS) and laparoscopic (LS) conditions in postoperative AF and we aimed to study peritoneal tissue inflammatory reaction (TIR), remodelling specific complications of open surgery (OS) versus LS and subsequently evaluating AF induced by these conditions. Methods A prospective randomized study was done in 80 anaesthetised female Wistar rats divided equally into 2 groups. Specific traumatic OS conditions were induced by midline incision line (MIL) extension and tissue drying and specific LS conditions were remodelled by intraperitoneal CO2 insufflation at the 10 cm of water. TIR was evaluated at the 24th, 72nd, 120th and 168th hour by scoring scale. Statistical analysis was performed by the non-parametric t test and two-way ANOVA using Bonferroni post-tests. Results More pronounced residual TIR was registered after OS than after LS. There were no significant TIR interactions though highly significant differences were observed between the OS and LS groups (p < 0.0001) with regard to surgical and time factors. The TIR change differences between the OS and LS groups were pronounced with postoperative time p < 0.05 at the 24th and 72nd; p < 0.01 - 120th and p < 0.001 - 168th hrs. Adhesion free wounds were observed in 20.0 and 31.0% of cases after creation of OS and LS conditions respectively; with no significant differences between these values (p > 0.05). However larger adhesion size (41.67 ± 33.63) was observed after OS in comparison with LS (20.31 ± 16.38). The upper-lower 95% confidential limits ranged from 60.29 to 23.04 and from 29.04 to 11.59 respectively after OS and LS groups with significant differences (p = 0.03). Analogous changes were observed in adhesion severity values. Subsequently, severe TIR parameters were followed by larger sizes of severe

  12. Numerical modelling of shock-induced chemical reactions (SICR) in reactive powder mixtures using smoothed particle hydrodynamics (SPH)

    NASA Astrophysics Data System (ADS)

    S, Siva Prasad A. V.; Basu, Sumit

    2015-10-01

    Shock compaction of reactive powder mixtures to synthesize new materials is one of the oldest material processing techniques and has been studied extensively by several researchers over the past few decades. The quantitative connection between the shock energy imparted and the extent of reaction that can be completed in the small time window associated with the passage of the shock wave is complicated and depends on a large variety of parameters. In particular, our understanding of the complex interplay between the thermo-elasto-viscoplastic behaviour of the granular constituents and their temperature dependent, diffusion-limited reaction mechanism may be enriched through careful numerical simulations. A robust numerical model should be able to handle extremely large deformations coupled with diffusion mediated fast reaction kinetics. In this work, a meshfree discrete particle numerical method based on smoothed particle hydrodynamics (SPH) to simulate shock-induced chemical reactions (SICR) in reactive powder mixtures is proposed. We present a numerical strategy to carry out reactions between reactant powder particles and partition the obtained products between the particles in a manner that accounts for the requirement that the total mass of the entire system remains constant as the reactions occur. Instead of solving the reaction-diffusion problem, we propose a ‘pseudo-diffusion’ model in which a distance dependent reaction rate constant is defined to carry out chemical reaction kinetics. This approach mimics the actual reaction-diffusion process at short times. Our numerical model is demonstrated for the well-studied reaction system Nb  +  2Si \\rightleftharpoons NbSi 2 . The predicted mass fractions of the product obtained from the simulations are in agreement with experimental observations. Finally, the effects of impact speed, particle arrangement and mixing ratio on the predicted product mass fractions are discussed.

  13. Control of laser induced reactions in solids using selected photon energies and pulse pairs

    NASA Astrophysics Data System (ADS)

    Hess, Wayne; Joly, Alan; Beck, Kenneth; Gerrity, Daniel; Dickinson, J. Thomas; Sushko, Peter; Shluger, Alexander

    2002-03-01

    Laser control of reaction dynamics is an intensely studied area of chemical physics. Sophisticated quantum and optimal control schemes have been developed to overcome difficulties associated with rapid energy redistribution from laser-prepared initial states. Experiment and theory have demonstrated how specific product pathways can be selected by irradiation with one or more laser beams. Although most laser control research has focused on small gas-phase molecules, product and quantum state control of laser desorption from solids is possible using delayed pulse pairs, selected pulse duration or by judicious choice of laser wavelength. Theory indicates that it is possible to excite the surface of ionic crystals, over the bulk, using tunable laser sources.[1] We recently demonstrated control of ion emission from MgO surfaces[2] using femtosecond pulse pairs and nearly exclusive emission of hyperthermal Br (2P3/2) from laser excited KBr.[3] Here, we explore the mechanism of laser desorption in experiments using delayed pulse pairs and tunable single pulses. The first laser pulse induces formation of transient species and the second pulse then excites the intermediate state to induce desorption of selected species or quantum states. Selective desorption raises the intriguing prospect of selective surface modification. The principles described here should be extendable to other alkali halides and metal oxides. References: [1] A.L. Shluger, P.V. Sushko, and L.N. Kantorovich, Phys. Rev. B. 59, (1999) 2417. [2] K.M. Beck, A.G. Joly, and W.P. Hess, Sur. Sci. 451, 166 (2000). [3] W. P. Hess, A. G. Joly, K. M. Beck, D. P. Gerrity, P. V. Sushko, and A. L. Shluger, J. Chem. Phys. 115, 9463 (2001).

  14. Oxygen reduction reaction induced pH-responsive chemo-mechanical hydrogel actuators.

    PubMed

    Yu, Cunjiang; Yuan, Peixi; Erickson, Evan M; Daly, Christopher M; Rogers, John A; Nuzzo, Ralph G

    2015-10-28

    We describe and characterize elementary designs for electrochemical micro- and macro-scale chemomechanical hydrogel actuators. The actuation of a pH-sensitive cross-linked polyacrylic acid (PAA) hydrogel is driven in the model devices through the oxygen reduction reaction (ORR) occurring at the electrodes of an embedded Au mesh micro-electrochemical array. Proton consumption by the ORR at the cathode of the embedded electrochemical cell leads to the formation of a localized pH gradient that in turn drives the strain response in the composite actuators. The dynamics result from the ionization of the carboxylic acid moieties of the PAA network in the high pH region, yielding an osmotic pressure that drives a volumetric expansion due to water imbibition. This system actuates both stably and reversibly; when the electrochemically-induced ORR is halted, the localized pH gradient dissipates due to diffusive mixing, which in turn relaxes the induced strains. Two approaches to the fabrication of hydrogel actuators were examined in this work. The first method adopted a design based on small flagella (∼0.2 mm × 1.5 mm × 60 μm, width × length × height) in which the actuating PAA structures are molded atop a set of fixed electrodes mounted on a supporting substrate. These hydrogel actuators show fast, large-amplitude, and largely reversible responses in the ORR mediated chemomechanical dynamics. We also investigated larger hydrogel actuators (∼4.5 mm × 11 mm × 1 mm, width × length × height), based on an autonomous design that embeds an open mesh stretchable micro-electrode array within the hydrogel. The significant and design-dependent impacts of mass transfer on the chemomechanical dynamics are evidenced in each case, a feature examined to elucidate more efficient mesoscopic design rules for actuators of this form. PMID:26323563

  15. Mediator profiles in tears during the conjunctival response induced by allergic reaction in the nasal mucosa

    PubMed Central

    2013-01-01

    Background The allergic reaction occurring primarily in the nasal mucosa can induce a secondary conjunctival response of an immediate (SICR), late (SLCR), or delayed (SDYCR) type in some patients with allergic conjunctivitis (AC). Objectives To investigate the concentration changes of histamine, tryptase, eosinophil cationic protein (ECP), eosinophil-derived neurotoxin (EDN), leukotrienes (LTB 4, LTC4, LTE4), myeloperoxidase (MPO), interferon-γ (IFN-γ), and interleukins (IL-2, IL-4, IL-5) in tears during the SICR, SLCR, and SDYCR. Methods In 32 patients with AC, 11 SICR (p<0.01), 13 SLCR (p<0.001), and eight SDYCR (p<0.01) to nasal challenges with allergens (NPTs), the NPTs and 32 control tests with PBS were repeated and supplemented with the determination of these factors in tears. Results The SICRs were associated with significant concentration changes in tears (p<0.05) of histamine, tryptase, ECP, LTC4, and IL-4. The SLCRs were accompanied by significant changes in concentrations of histamine, ECP, LTB4, LTC4, MPO, IL-4, and IL-5. The SDYCRs were associated with significant concentration changes in tears (p<0.05) of LTB4, MPO, IFN-γ, and IL-2. No significant changes in these factors were recorded in tears during the 32 PBS controls (p>0.1) or in the ten control patients (p>0.1). Conclusions These results provide evidence for causal involvement of nasal allergy in some patients with AC, inducing secondary conjunctival response of immediate (SICR), late SLCR, or delayed SDYCR type, associated with different mediator, cytokine, and cellular profiles in the tears, suggesting involvement of different hypersensitivity mechanisms. These results also emphasize the diagnostic value of nasal allergen challenge combined with monitoring of the conjunctival response in some patients with AC. PMID:23869165

  16. Photo-SRM: laser-induced dissociation improves detection selectivity of Selected Reaction Monitoring mode.

    PubMed

    Enjalbert, Quentin; Simon, Romain; Salvador, Arnaud; Antoine, Rodolphe; Redon, Sébastien; Ayhan, Mehmet Menaf; Darbour, Florence; Chambert, Stéphane; Bretonnière, Yann; Dugourd, Philippe; Lemoine, Jérôme

    2011-11-30

    Selected Reaction Monitoring (SRM) carried out on triple-quadrupole mass spectrometers coupled to liquid chromatography has been a reference method to develop quantitative analysis of small molecules in biological or environmental matrices for years and is currently emerging as a promising tool in clinical proteomic. However, sensitive assays in complex matrices are often hampered by the presence of co-eluted compounds that share redundant transitions with the target species. On-the-fly better selection of the precursor ion by high-field asymmetric waveform ion mobility spectrometry (FAIMS) or increased quadrupole resolution is one way to escape from interferences. In the present work we document the potential interest of substituting classical gas-collision activation mode by laser-induced dissociation in the visible wavelength range to improve the specificity of the fragmentation step. Optimization of the laser beam pathway across the different quadrupoles to ensure high photo-dissociation yield in Q2 without detectable fragmentation in Q1 was assessed with sucrose tagged with a push-pull chromophore. Next, the proof of concept that photo-SRM ensures more specific detection than does conventional collision-induced dissociation (CID)-based SRM was carried out with oxytocin peptide. Oxytocin was derivatized by the thiol-reactive QSY® 7 C(5)-maleimide quencher on cysteine residues to shift its absorption property into the visible range. Photo-SRM chromatograms of tagged oxytocin spiked in whole human plasma digest showed better detection specificity and sensitivity than CID, that resulted in extended calibration curve linearity. We anticipate that photo-SRM might significantly improve the limit of quantification of classical SRM-based assays targeting cysteine-containing peptides. PMID:22002689

  17. Investigation of Shock-Induced Chemical Reactions in Mo-Si Powder Mixtures Using Instrumented Experiments with PVDF Stress Gauges

    SciTech Connect

    Vandersall, K S; Thadhani, N N

    2001-05-29

    Shock-induced chemical reactions in {approx}58% dense Mo+2Si powder mixtures were investigated using time-resolved instrumented experiments, employing PVDF-piezoelectric stress gauges placed at the front and rear surfaces of the powders to measure the input and propagated stresses, and wave speed through the powder mixture. Experiments performed on the powders at input stresses less than 4 GPa, showed characteristics of powder densification and dispersed propagated wave stress profiles with rise time > {approx}40 nanoseconds. At input stress between 4-6 GPa, the powder mixtures showed a sharp rise time (<{approx}10 ns) of propagated wave profile and an expanded state of products revealing evidence of shock-induced chemical reaction. At input stresses greater than 6 GPa, the powder mixtures showed a slower propagated-stress-wave rise time and transition to a low-compressibility (melt) state indicating lack of shock-induced reaction. The results illustrate that premature melting of Si, at input stresses less than the crush-strength of the powder mixtures, restricts mixing between reactants and inhibits ''shock-induced'' reaction initiation.

  18. Revised Calculations of the Production Rates for Co Isotopes in Meteorites Using New Cross Sections for Neutron-induced Reactions

    NASA Technical Reports Server (NTRS)

    Sisterson, J. M.; Brooks, F. D.; Buffler, A.; Allie, M. S.; Herbert, M. S.; Nchodu, M. R.; Makupula, S.; Ullmann, J.; Reedy, R. C.; Jones, D. T. L.

    2002-01-01

    New cross section measurements for reactions induced by neutrons with energies greater than 70 MeV are used to calculate the production rates for cobalt isotopes in meteorites and these new calculations are compared to previous estimates. Additional information is contained in the original extended abstract.

  19. Difunctionalization of Alkenes via the Visible-Light-Induced Trifluoromethylarylation/1,4-Aryl Shift/Desulfonylation Cascade Reactions.

    PubMed

    Zheng, Lewei; Yang, Chao; Xu, ZhaoZhong; Gao, Fei; Xia, Wujiong

    2015-06-01

    A novel visible-light-induced trifluoromethylarylation/1,4-aryl shift/desulfonylation cascade reaction using CF3SO2Cl as CF3 source was described. The protocol provides an efficient approach for the synthesis of α-aryl-β-trifluoromethyl amides and/or CF3-containing oxindoles as well as the isoquinolinediones under benign conditions. PMID:25955879

  20. Molecular cloning and characterization of two hypersensitive induced reaction genes from wheat infected by stripe rust pathogen

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A novel gene induced during hypersensitive reaction (HIR) in wheat was identified using in silico cloning and designated as TaHIR2. The TaHIR2 gene was deduced to encode a 284-amino acid protein, whose molecular mass and isoelectric point (pI) were 31.05 kD and 5.18, respectively. Amino acid sequenc...