Gamma ray production cross sections in proton induced reactions on natural Mg, Si and Fe targets over the proton energy range 30 up to 66 MeV

Gamma-ray excitation functions have been measured for 30, 42, 54 and 66 MeV proton beams accelerated onto C + O (Mylar), Mg, Si, and Fe targets of astrophysical interest at the separate-sector cyclotron of iThemba LABS in Somerset West (Cape Town, South Africa). A large solid angle, high energy resolution detection system of the Eurogam type was used to record Gamma-ray energy spectra. Derived preliminary results of Gamma-ray line production cross sections for the Mg, Si and Fe target nuclei are reported and discussed. The current cross section data for known, intense Gamma-ray lines from these nuclei consistently extend to higher proton energies previous experimental data measured up to Ep ~ 25 MeV at the Orsay and Washington tandem accelerators. Data for new Gamma-ray lines observed for the first time in this work are also reported.Comment: 11 pages, 6 figures. IOP Institute of Physics Conference Nuclear Physics in Astrophysics VII, 28th EPF Nuclear Physics Divisional Conference, May 18-22 2015, York, U

Acute myocardial infarction in a patient with hypofibrinogenemia: a case report

<p>Abstract</p> <p>Introduction</p> <p>Congenital fibrinogen deficiency is a rare coagulation disorder usually responsible for hemorrhagic diathesis. However, it can be associated with thrombosis and there have been limited reports of arterial thrombotic complications in these patients.</p> <p>Case presentation</p> <p>A 42-year-old Tunisian man with congenital hypofibrinogenemia and no cardiovascular risk factors presented with new onset prolonged angina pectoris. An electrocardiogram showed features of inferior acute myocardial infarction. His troponin levels had reached 17 ng/L. Laboratory findings confirmed hypofibrinogenemia and ruled out thrombophilia. Echocardiography was not useful in providing diagnostic elements but did show preserved left ventricular function. Coronary angiography was not performed and our patient did not receive any anticoagulant treatment due to the major risk of bleeding. Magnetic resonance imaging confirmed myocardial necrosis. Our patient was managed with aspirin, a beta-blocker, an angiotensin-converting enzyme inhibitor and statin medication. The treatment was well tolerated and no ischemic recurrence was detected.</p> <p>Conclusion</p> <p>Although coronary thrombosis is a rare event in patients with fibrinogen deficiency, this condition is of major interest in view of the difficulties observed in managing these patients.</p

Measurement and analysis of nuclear γ-ray production cross sections in proton interactions with Mg, Si, and Fe nuclei abundant in astrophysical sites over the incident energy range E = 30–66 MeV

The modeling of nuclear γ -ray line emission induced by highly accelerated particles in astrophysical sites (e.g., solar flares, the gas and dust in the inner galaxy) and the comparison with observed emissions from these sites needs a comprehensive database of related production cross sections. The most important reactions of protons and α particles are those with abundant target elements like C, O, N, Ne, Mg, Si, and Fe at projectile energies extending from the reaction threshold to a few hundred MeV per nucleon. In this work, we have measured γ -ray production cross section excitation functions for 30, 42, 54, and 66 MeV proton beams accelerated onto nat C , C + O (Mylar), nat Mg , nat Si , and 56 Fe targets of astrophysical interest at the Separated Sector Cyclotron (SSC) of iThemba LABS (near Cape Town, South Africa). The AFRODITE array equipped with eight Compton suppressed high-purity (HPGe) clover detectors was used to record γ -ray line energy spectra. For known, intense lines previously reported experimental data measured up to E p ≃ 25 MeV at the Washington and Orsay tandem accelerators were thus extended to higher proton energies. Our experimental data for the last three targets are reported here and discussed with respect to previous data and to the Murphy et al. compilation [Astrophys. J. Suppl. Ser. 183, 142 (2009)]

Gd3+-Eu3+ energy transfer and Judd-Ofelt analysis of Eu3+ doped -NaGdF4 nanorods obtained by rapid coprecipitation method.

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Judd-Ofelt and quantum cutting analysis of Eu3+ or Pr3+ doped β-NaGdF4 nanorods obtained by rapid coprecipitation method

International audiencePure hexagonal β-NaGdF 4 and Eu 3+ or Pr 3+-doped β-NaGdF 4 nanocrystals in shape of nanorods of ∼140 nm of length have been synthesized using a simple and rapid coprecipitation method. XRD analysis evidenced pure single phases exhibiting characteristic luminescence of Eu 3+ or Pr 3+ ions when excited under UV or blue radiations. Samples gave rise to intense orange-red emission and quite white emission in the case of respectively Eu 3+ or Pr 3+ doped samples. Optical properties are discussed in the frame of Judd-Ofelt theory and considering that an energy transfer occurs between active ions. Notably it was found that the quantum-cutting by a two-step energy transfer from Gd 3+ to Eu 3+ can improve the red emission of Eu 3+ ions under near-VUV excitation. Such quantum-cutting mechanism has been also considered in the case of Pr 3+ doped β-NaGdF 4. However, the efficiency of both processes in comparison with literature suggest that only one part of the energy in the excited states within Gd 3+ can be transferred to Eu 3+ for its red emission. In the case of Pr 3+ ions, the energy is more probably released through the self-trapped exciton emission certainly due to the lack of resonant VUV excitation

Energy transfer and luminescent properties of Tb3+, and Tb3+-Yb3+ doped -NaYF4 nanophosphors prepared by coprecipitation route.

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Energy transfer and luminescent properties of Eu3+, Tb3+, Eu3+-Yb3+and Tb3+-Yb3+ doped α-NaYF4 nanophosphors prepared by coprecipitation route

International audienceEnergy transfer and luminescent properties of Eu 3þ , Tb 3þ , Eu 3þ-Yb 3þ and Tb 3þ-Yb 3þ doped α-NaYF 4 nanophosphors prepared by coprecipitation rout

Coprecipitation synthesis and optical characterization of Tb3+ and Tb3+-Yb3+doped α-NaYF4 nanophosphors. En distanciel

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Evidence of visible quantum cutting phenomenon in co-precipitation derived Eu3+ doped β-NaGdF4 nanorods. (en distanciel)

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