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Träfflista för sökning "WFRF:(Janik Dirk) "

Search: WFRF:(Janik Dirk)

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1.
  • Abbasi, Rasha, et al. (author)
  • IceCube search for neutrinos from GRB 221009A
  • 2023
  • In: Proceedings of 38th International Cosmic Ray Conference (ICRC 2023). - : Sissa Medialab Srl.
  • Conference paper (peer-reviewed)abstract
    •  GRB 221009A is the brightest Gamma Ray Burst (GRB) ever observed. The observed extremelyhigh flux of high and very-high-energy photons provide a unique opportunity to probe the predictedneutrino counterpart to the electromagnetic emission. We have used a variety of methods to searchfor neutrinos in coincidence with the GRB over several time windows during the precursor, promptand afterglow phases of the GRB. MeV scale neutrinos are studied using photo-multiplier ratescalers which are normally used to search for galactic core-collapse supernovae neutrinos. GeVneutrinos are searched starting with DeepCore triggers. These events don’t have directionallocalization, but instead can indicate an excess in the rate of events. 10 GeV - 1 TeV and >TeVneutrinos are searched using traditional neutrino point source methods which take into accountthe direction and time of events with DeepCore and the entire IceCube detector respectively. The>TeV results include both a fast-response analysis conducted by IceCube in real-time with timewindows of T0 − 1 to T0 + 2 hours and T0 ± 1 day around the time of GRB 221009A, as well asan offline analysis with 3 new time windows up to a time window of T0 − 1 to T0 + 14 days, thelongest time period we consider. The combination of observations by IceCube covers 9 ordersof magnitude in neutrino energy, from MeV to PeV, placing upper limits across the range forpredicted neutrino emission.
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2.
  • Azimzadeh, Omid, et al. (author)
  • PPAR Alpha: A Novel Radiation Target in Locally Exposed Mus musculus Heart Revealed by Quantitative Proteomics
  • 2013
  • In: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 12:6, s. 2700-2714
  • Journal article (peer-reviewed)abstract
    • Radiation exposure of the thorax is associated with a markedly increased risk of cardiac morbidity and mortality with a latency period of decades. Although many studies have confirmed the damaging effect of ionizing radiation on the myocardium and cardiac endothelial structure and function, the molecular mechanism behind this damage is not yet elucidated. Peroxisome proliferator-activated receptor alpha (PPAR alpha), a transcriptional regulator of lipid metabolism in heart tissue, has recently received great attention in the development of cardiovascular disease. The goal of this study was to investigate radiation-induced cardiac damage in general and the role of PPAR alpha in this process in particular. C57BL/6 mice received local heart irradiation with X-ray doses of 8 and 16 gray (Gy) at the age of 8 weeks. The mice were sacrificed 16 weeks later. Radiation-induced changes in the cardiac proteome were quantified using the Isotope Coded Protein Label (ICPL) method followed by mass spectrometry and software analysis. Significant alterations were observed in proteins involved in lipid metabolism and oxidative phosphorylation. Ionizing radiation markedly changed the phosphorylation and ubiquitination status of PPAR alpha. This was reflected as decreased expression of its target genes involved in energy metabolism and mitochondrial respiratory chain confirming the proteomics data. This study suggests that persistent alteration of cardiac metabolism due to impaired PPAR alpha activity contributes to the heart pathology after radiation.
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3.
  • Benzoni, G., et al. (author)
  • First Measurement of Beta Decay Half-lives in Neutron-rich Tl and Bi Isotopes
  • 2012
  • In: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 715:4-5, s. 293-297
  • Journal article (peer-reviewed)abstract
    • Neutron-rich isotopes around lead, beyond N = 126, have been studied exploiting the fragmentation of an uranium primary beam at the FRS-RISING setup at GSI. For the first time beta-decay half-lives of Bi-219 and Tl-211,Tl-212,Tl-213 isotopes have been derived. The half-lives have been extracted using a numerical simulation developed for experiments in high-background conditions. Comparison with state of the art models used in r-process calculations is given, showing a systematic underestimation of the experimental values, at variance from close-lying nuclei. (c) 2012 Elsevier B.V. All rights reserved.
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4.
  • Bruce, A. M., et al. (author)
  • Beta Decay of 102Y Produced in Projectile Fission of 238U
  • 2012
  • In: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6596 .- 1742-6588. ; 381
  • Journal article (peer-reviewed)abstract
    • The population of 102Zr following the β decay of 102Y produced in the projectile fission of 238U at the GSI facility in Darmstadt, Germany has been studied. 102Y is known to ß decay into 102Zr via two states, one of high spin and the other low spin. These states preferentially populate different levels in the 102Zr daughter. In this paper the intensities of transitions in 102Zr observed are compared with those from the decay of the low-spin level studied at the TRISTAN facility at Brookhaven National Laboratory and of the high-spin level studied at the JOSEF separator at the Kernforschungsanlage Jülich.
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5.
  • Eisenberg, Tobias, et al. (author)
  • Cardioprotection and lifespan extension by the natural polyamine spermidine
  • 2016
  • In: Nature Medicine. - : Springer Science and Business Media LLC. - 1078-8956 .- 1546-170X. ; 22:12, s. 1428-1438
  • Journal article (peer-reviewed)abstract
    • Aging is associated with an increased risk of cardiovascular disease and death. Here we show that oral supplementation of the natural polyamine spermidine extends the lifespan of mice and exerts cardioprotective effects, reducing cardiac hypertrophy and preserving diastolic function in old mice. Spermidine feeding enhanced cardiac autophagy, mitophagy and mitochondrial respiration, and it also improved the mechano-elastical properties of cardiomyocytes in vivo, coinciding with increased titin phosphorylation and suppressed subclinical inflammation. Spermidine feeding failed to provide cardioprotection in mice that lack the autophagy-related protein Atg5 in cardiomyocytes. In Dahl salt-sensitive rats that were fed a high-salt diet, a model for hypertension-induced congestive heart failure, spermidine feeding reduced systemic blood pressure, increased titin phosphorylation and prevented cardiac hypertrophy and a decline in diastolic function, thus delaying the progression to heart failure. In humans, high levels of dietary spermidine, as assessed from food questionnaires, correlated with reduced blood pressure and a lower incidence of cardiovascular disease. Our results suggest a new and feasible strategy for protection against cardiovascular disease.
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6.
  • Gottardo, A., et al. (author)
  • Isomeric Decay Spectroscopy of the 217Bi Isotope
  • 2014
  • In: Physical Review C (Nuclear Physics). - 0556-2813. ; 90:3
  • Journal article (peer-reviewed)abstract
    • The structure of the neutron-rich bismuth isotope 217Bi has been studied for the first time. The fragmentation of a primary 238U beam at the FRS-RISING setup at GSI was exploited to perform γ-decay spectroscopy, since μs isomeric states were expected in this nucleus. Gamma rays following the decay of a t1/2=3 μs isomer were observed, allowing one to establish the low-lying structure of 217Bi. The level energies and the reduced electric quadrupole transition probability B(E2) from the isomeric state are compared to large-scale shell-model calculations.
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7.
  • Gottardo, A., et al. (author)
  • Isomers in Neutron-rich Lead Isotopes Populated via the Fragmentation of 238U at 1 GeV A
  • 2011
  • In: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6596 .- 1742-6588. ; 312
  • Journal article (peer-reviewed)abstract
    • Neutron-rich nuclei beyond N = 126 in the lead region were populated by fragmenting a 238U beam at 1 GeV A on a Be target and then separated by the Fragment Separator (FRS) at GSI. Their isomeric decays were observed, enabling study of the shell structure of neutron-rich nuclei around the Z=82 shell closure. Some preliminary results are reported in this paper.
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8.
  • Gottardo, A., et al. (author)
  • New Isomers in the Full Seniority Scheme of Neutron-rich Lead Isotopes: The Role of Effective Three-body Forces
  • 2012
  • In: Physical Review Letters. - 1079-7114. ; 109:16
  • Journal article (peer-reviewed)abstract
    • The neutron-rich lead isotopes, up to Pb-216, have been studied for the first time, exploiting the fragmentation of a primary uranium beam at the FRS-RISING setup at GSI. The observed isomeric states exhibit electromagnetic transition strengths which deviate from state-of-the-art shell-model calculations. It is shown that their complete description demands the introduction of effective three-body interactions and two-body transition operators in the conventional neutron valence space beyond Pb-208.
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9.
  • Gottardo, A., et al. (author)
  • New Isomers in the Neutron-Rich Region Beyond 208Pb
  • 2014
  • In: EPJ Web of Conferences. - : EDP Sciences. - 2100-014X. - 9782759811755 - 9782759811762 ; 66, s. 02043-02043
  • Conference paper (peer-reviewed)abstract
    • The region of neutron-rich nuclei beyond 208Pb has been very difficult to explore due to its high mass and exoticity. However, recent experimental improvements allowed one to perform a quite extended isomer decay spectroscopy of these nuclei.
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10.
  • Gottardo, A., et al. (author)
  • New μs Isomers in the Neutron-rich 210Hg Nucleus
  • 2013
  • In: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 725:4-5, s. 292-296
  • Journal article (peer-reviewed)abstract
    • Neutron-rich nuclei in the lead region, beyond N = 126, have been studied at the FRS-RISING setup at GSI, exploiting the fragmentation of a primary uranium beam. Two isomeric states have been identified in Hg-210: the 8(+) isomer expected from the seniority scheme in the vg(9/2) shell and a second one at low spin and low excitation energy. The decay strength of the 8(+) isomer confirms the need of effective three-body forces in the case of neutron-rich lead isotopes. The other unexpected low-lying isomer has been tentatively assigned as a 3(-) state, although this is in contrast with theoretical expectations. (C) 2013 Elsevier B.V. All rights reserved.
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  • Result 1-10 of 13

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