271 research outputs found
First observation of γ rays emitted from excited states south-east of Sn132: The πg−19/2⊗νf7/2 multiplet of In83132
A. Jungclaus et al. ; 6 págs.; 4 figs. ; Rapid CommunicationsFor the first time, the γ decay of excited states has been observed in a nucleus situated in the quadrant south-east of doubly magic Sn132, a region in which experimental information so far is limited to ground-state properties. Six γ rays with energies of 50, 86, 103, 227, 357, and 602 keV were observed following the β-delayed neutron emission from Cd85133, populated in the projectile fission of a U238 beam at the Radioactive Isotope Beam Factory at RIKEN within the EURICA project. The new experimental information is compared to the results of a modern realistic shell-model calculation, the first one in this region very far from stability, focusing in particular on the π0g9/2-1 - ν1f7/2 particle-hole multiplet in In83132. In addition, theoretical estimates based on a scaling of the two-body matrix elements for the πh11/2-1 - νg9/2 analog multiplet in Tl127208, one major proton and one major neutron shell above, are presented. ©2016 American Physical SocietyWe thank the staff of the RIKEN Nishina Center accelerator
complex for providing stable beams with high intensities to
the experiment. We acknowledge the EUROBALL Owners
Committee for the loan of germanium detectors and the
PreSpec Collaboration for the readout electronics of the
cluster detectors. This work was supported by the Spanish
Ministerio de Ciencia e Innovación under Contract No.
FPA2011-29854-C04 and the Spanish Ministerio de Economía
y Competitividad under Contract No. FPA2014-57196-C5-
4-P, the Generalitat Valenciana (Spain) under Grant No.
PROMETEO/2010/101, the National Research Foundation of
Korea (NRF) grant funded by the Korea government (MEST)
(No. NRF-2012R1A1A1041763), the Priority Centers Research
Program in Korea (2009-0093817), OTKA Contract
No. K-100835, JSPS KAKENHI (Grant No. 25247045), the
European Commission through the Marie Curie Actions call
PEOPLE-2011FP7-IEF under Contract No. 300096 and the
German BMBF (No. 05P12RDCIA and No. 05P12RDNUP),
and Helmholtz International Center for FAIR.Peer Reviewe
β-Decay Half-Lives of 110 Neutron-Rich Nuclei across the N = 82 Shell Gap: Implications for the Mechanism and Universality of the Astrophysical r Process
G. Larusso et al.; 7 pags.; 5 figs.; 2 tabs.; PACS numbers: 23.40.-s, 26.30.Hj, 27.60.+j© 2015 American Physical Society. The β-decay half-lives of 110 neutron-rich isotopes of the elements from 37Rb to 50Sn were measured at the Radioactive Isotope Beam Factory. The 40 new half-lives follow robust systematics and highlight the persistence of shell effects. The new data have direct implications for r-process calculations and reinforce the notion that the second (A ≈ 130) and the rare-earth-element (A ≈ 160) abundance peaks may result from the freeze-out of an (n, γ) ⇄ (γ,n) equilibrium. In such an equilibrium, the new half-lives are important factors determining the abundance of rare-earth elements, and allow for a more reliable discussion of the r process universality. It is anticipated that universality may not extend to the elements Sn, Sb, I, and Cs, making the detection of these elements in metal-poor stars of the utmost importance to determine the exact conditions of individual r-process events.Part of the WAS3ABi was supported by the Rare
Isotope Science Project which is funded by the Ministry of
Education, Science, and Technology (MEST) and National
Research Foundation (NRF) of Korea. This work was
partially supported by KAKENHI (Grants No. 25247045,
No. 2301752, and No. 25800130), the RIKEN Foreign
Research Program, the Spanish Ministerio de Ciencia e
Innovación (Contracts No. FPA2009-13377-C02 and
No. FPA2011-29854-C04), the U.S. Department of
Energy, Office of Science, Office of Nuclear Physics,
Contract No. DE-AC02-06CH11357, the NASA Grant
No. NNX10AH78G, and the Hungarian Scientific
Research Fund OTKA Contract No. K100835.Peer Reviewe
Systematic Evaluation of Fluorination as Modification for Peptide‐Based Fusion Inhibitors against HIV‐1 Infection
With the emergence of novel viruses, the development of new antivirals is more urgent than ever. A key step in human immunodeficiency virus type 1 (HIV-1) infection is six-helix bundle formation within the envelope protein subunit gp41. Selective disruption of bundle formation by peptides has been shown to be effective; however, these drugs, exemplified by T20, are prone to rapid clearance from the patient. The incorporation of non-natural amino acids is known to improve these pharmacokinetic properties. Here, we evaluate a peptide inhibitor in which a critical Ile residue is replaced by fluorinated analogues. We characterized the influence of the fluorinated analogues on the biophysical properties of the peptide. Furthermore, we show that the fluorinated peptides can block HIV-1 infection of target cells at nanomolar levels. These findings demonstrate that fluorinated amino acids are appropriate tools for the development of novel peptide therapeutics
β decay of 129Cd and excited states in 129In
J. Taprogge et al.; 11 pags.; 8 figs.; 2 tabs.; PACS number(s): 23.20.Lv, 23.40.−s, 21.60.Cs, 27.60.+j©2015 American Physical Society. The β decay of 129Cd, produced in the relativistic fission of a 238U beam, was experimentally studied at the
RIBF facility at the RIKEN Nishina Center. From the γ radiation emitted after the β decays, a level scheme of 129In was established comprising 31 excited states and 69 γ -ray transitions. The experimentally determined level
energies are compared to state-of-the-art shell-model calculations. The half-lives of the two β-decaying states in 129Cd were deduced and the β feeding to excited states in 129In were analyzed. It is found that, as in most cases
in the Z < 50, N 82 region, both decays are dominated by the ν0g7/2 → π0g9/2 Gamow–Teller transition,
although the contribution of first-forbidden transitions cannot be neglected.This work was supported
by the Spanish Ministerio de Ciencia e Innovacion
under contracts FPA2009-13377-C02 and FPA2011-29854-
C04, the Generalitat Valenciana (Spain) under grant PROMETEO/2010/101,
the National Research Foundation of Korea
(NRF) grant funded by the Korea government (MEST) (No.
NRF-2012R1A1A1041763), the Priority Centers Research
Program in Korea (2009-0093817), OTKA contract number
K-100835, JSPS KAKENHI (Grant No. 25247045), the
European Commission through the Marie Curie Actions call
FP7-PEOPLE-2011-IEF under Contract No. 300096, the US
Department of Energy, Office of Nuclear Physics, under
Contract No. DE-AC02-06CH11357, the “RIKEN foreign
research program,” and the German BMBF (No. 05P12RDCIA
and 05P12RDNUP) and HIC for FAIR.Peer Reviewe
Age-related decline of peripheral visual processing: the role of eye movements
Earlier work suggests that the area of space from which useful visual information can be extracted (useful field of view, UFoV) shrinks in old age. We investigated whether this shrinkage, documented previously with a visual search task, extends to a bimanual tracking task. Young and elderly subjects executed two concurrent tracking tasks with their right and left arms. The separation between tracking displays varied from 3 to 35 cm. Subjects were asked to fixate straight ahead (condition FIX) or were free to move their eyes (condition FREE). Eye position was registered. In FREE, young subjects tracked equally well at all display separations. Elderly subjects produced higher tracking errors, and the difference between age groups increased with display separation. Eye movements were comparable across age groups. In FIX, elderly and young subjects tracked less well at large display separations. Seniors again produced higher tracking errors in FIX, but the difference between age groups did not increase reliably with display separation. However, older subjects produced a substantial number of illicit saccades, and when the effect of those saccades was factored out, the difference between young and older subjects’ tracking did increase significantly with display separation in FIX. We conclude that the age-related shrinkage of UFoV, previously documented with a visual search task, is observable with a manual tracking task as well. Older subjects seem to partly compensate their deficit by illicit saccades. Since the deficit is similar in both conditions, it may be located downstream from the convergence of retinal and oculomotor signals
Isomers in 128Pd and 126Pd: Evidence for a robust shell closure at the neutron magic number 82 in exotic palladium isotopes
Monopole-driven shell evolution below the doubly magic nucleus 132Sn explored with the long-lived isomer in 126Pd
Study of ground and excited state decays in N approximate to Z Ag nuclei
4 pags., 4 figs. -- CGS15 – Capture Gamma-Ray Spectroscopy and Related TopicsA decay spectroscopy experiment was performed within the EURICA campaign at RIKEN in 2012. It aimed at the isomer and particle spectroscopy of excited states and ground states in the mass region below the doubly magic 100Sn. The N = Z nuclei 98In, 96Cd and 94Ag were of particular interest for the present study. Preliminary results on the neutron deficient nuclei 93Ag and 94Ag are presented. In 94Ag a more precise value for the half-life of the ground state’s superallowed Fermi transition was deduced. In addition the energy spectra of the mentioned decay could be reproduced through precise Geant4 simulations of the used active stopper SIMBA. This will enable us to extract Qβ values from the measured data. The decay of 93Ag is discussed based on the observed implantation-decay correlation events.This work was carried out at the RIBF operated by RIKEN
Nishina Center, RIKEN and CNS, University of Tokyo.
We acknowledge the EUROBALL Owners Committee for
the loan of germanium detectors and the PreSpec Collaboration for the readout electronics of the cluster detectors.
This work was supported by the German BMBF under
Contract No. 05P12PKFNE and by the U.S. Department
of Energy under grant No. DE-FG02-91ER-40609
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