138 research outputs found

    Low-lying levels in 119^{119}Xe

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    The decays of 119m{}^{119m}Cs and 119g{}^{119g}Cs to 119{}^{119}Xe have been studied on mass separated samples, using γray\gamma\rm{-ray} and internal conversion electron measurements. Several new low-lying levels have been established in the 119{}^{119}Xe level scheme. Half-life evaluations for 119m{}^{119m}Cs and 119g{}^{119g}Cs have been revisited. The results are compared with other experimental data known in light odd-mass xenon isotopes and with calculations performed in the frame of the multi-shell interacting boson-fermion model

    Meson-exchange enhancement in first-forbidden β\beta -transitions: the case of 50^{50}K and 38^{38}Ca

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    The β\beta- decay of 50^{50}K and 38^{38}Ca have been investigated with the main motive of determining more accurately the first-forbidden β\beta- branches, in particular the rank-zero, Δ\DeltaJ = 0, β\,\beta -transitions. 50^{50}K and 38^{38}Ca have been produced by fragmentation of U and Ti targets respectively, with a 1 GeV proton beam and subsequent on-line mass separation. For 50^{50}K, γ\gamma-ray spectroscopy, as well as delayed neutron spectroscopy by time of flight, were carried out to obtain a detailed decay scheme to 20 (bound and unbound) levels in 50^{50}Ca. The level structur e of 50^{50}Ca can be compared to recent calculations which incorporate 1p1h excitations from the f7/2_{7/2} shell. The first-forbidden β\beta^- transition 50^{50} K(0^-)50\,\to{}^{50}Ca(0+^+) g.s. has been evaluated for the first time by a direct measurement of β\beta- and γ\gamma- activities. Its importance (61.0 ±\pm 7.4%\%) is interpreted as an effect of the meson-exchange current (MEC) l eading to an enhancement factor of 62(5)%\% in comparison with the value predicted by shell-model calculations using the impulse approximation. For the 38^{38} Ca38\,\to{}^{38}K decay, chemical selec tive production was obtained through separation of the molecular ion CaF+^+ without contamination by isobars. In these conditions, the measurement of very weak β\beta-branches, at a level of 103%^{-3}\% decays, could be made and a limit, at the 2σ\sigma-confidence level, has been obtained for the 0+^+\to 0^- branch to the level at Ex_x = 2993 keV (Iβ_\beta < 0.0046%\%). Imp lications of these results on the general trend of meson-exchange enhancements of first-forbidden transitions within the framework of the spherical shell model are discussed

    Proton instability of 73^{73}Rb

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    The steps of territorial intelligence are based on the emergence of new fashions of exchange within the territory . It acts thus on the territorial visibility and hustles the places of strategic reflexion; by doing this, it takes part within the country, to make move the bond sociétal. This paper subjects a posture of collection and mutualisation of information within the territory

    β\beta-decay half-life of 70^{70}Kr: a bridge nuclide for the rp-process beyond A = 70

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    The β\beta-decay half-life of 70^{70}Kr has been measured for the first time at the ISOLDE PSB Facility at CERN. Mass separated 70^{70}Kr ions were produced by 1 GeV proton induced spallation reactions in a Nb foil. The measured half-life is 57(21) ms. This value is consistent with the half-life calculated assuming a pure Fermi decay, but is clearly lower than the value used in a recent rp-process reaction flow calculation. The result shows that the reaction flow via two-proton-capture of 68^{68}Se is 2.5 times faster than previously calculated assuming an astrophysical temperature of 1.5 GK and a density of 106^{6}g/cm3^{3}

    β\beta- decay of the proton-rich Tz=1/2_{z} = -1/2 nucleus, 71^{71}Kr

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    β\beta- decay of the Tz_{z} = - 1/2 nuclide 71^{71}Kr has been studied at the ISOLDE PSB Facility at CERN. 71^{71}Kr ions were produced in spallation reactions in a Nb foil using the 1 GeV proton beam and studied by means of β\beta-delayed proton, β\beta- and γ\gamma-ray spectroscopy. The half-life and the β\beta-decay energy of 71^{71}Kr were determined using the decay of protons and positrons. These results: T1/2_{1/2} = 100 ± 3 ms and QECQ_\textrm{EC} = 1014^{14} ± 0.32 MeV and the first observation of the b-branch to the 207 keV level in 71^{71}Br makes the extension of the systematics of Gamow-Teller matrix elements of mirror nuclei up to A = 71 possible. Gamow-Teller strength of the same magnitude as that of the fpfp-shell mirror nuclei is observed for the ground state transition

    Effect of Dexrazoxane and Amifostine on the Vertebral Bone Quality of Doxorubicin Treated Male Rats

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    Doxorubicin (DOX) is widely used in combination cocktails for treatment of childhood hematological cancers and solid tumors. A major factor limiting DOX usage is DOX-induced cardiotoxicity. However, it is not known whether protectants like dexrazoxane (DXR) and amifostine (AMF) can prevent DOX-mediated bone damage. The present study investigated whether administration of AMF alone or in combination with DXR would prevent any DOX-mediated bone damage. Male rat pups were treated with DOX, DXR, AMF, and their combinations. On neonate day 38, the bone mineral density (BMD), bone mineral content (BMC) and the micro-architecture of the lumbar vertebrae were analyzed. We have shown that when male rats are treated with DOX, DXR, DOX+DXR, AMF, DOX+AMF or DOX+DXR+AMF, there is a decrease in lumbar vertebral BMD (p<0.05). Furthermore, the relative bone volume (BV/TV) was decreased by DXR, DOX+DXR, and DOX+AMF treatments. Interestingly, DOX+AMF significantly increased BV/TV when compared to DXR treatment (p<0.04). The trabecular number (Tb.N) decreased with DXR and DOX+DXR and increased with DOX+AMF treatments. This information will be useful in designing better cancer combination therapies that do not lead to vertebrae deterioration

    Bacterial Colonization of Low‐Wettable Surfaces is Driven by Culture Conditions and Topography

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    Effect of surface low‐wettability on bacterial colonization has become a prominent subject for the development of antibacterial coatings. However, bacteria's fate on such surfaces immersed in liquid as well as causal factors is poorly understood. This question is addressed by using a range of coatings with increasing hydrophobicity, to superhydrophobic, obtained by an atmospheric plasma polymer method allowing series production. Chemistry, wettability, and topography are thoroughly described, as well as bacterial colonization by in situ live imaging up to 24 h culture time in different liquid media. In the extreme case of superhydrophobic coating, substrates are significantly less colonized in biomolecule‐poor liquids and for short‐term culture only. Complex statistical analysis demonstrates that bacterial colonization on these low‐wettable substrates is predominantly controlled by the culture conditions and only secondary by topographic coating's properties (variation in surface structuration with almost constant mean height). Wettability is less responsible for bacterial colonization reduction in these conditions, but allows the coatings to preserve colonization‐prevention properties in nutritive media when topography is masked by fouling. Even after long‐term culture in rich medium, many large places of the superhydrophobic coating are completely free of bacteria in relation to their capacity to preserve air trapping

    31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

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    Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival
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