The γ-ray decay of excited states of the one-valence-proton nucleus 133Sb has been studied using cold-neutron induced fission of 235U and 241Pu targets, during the EXILL campaign at the ILL reactor ...in Grenoble. By using a highly efficient HPGe array, coincidences between γ-rays prompt with the fission event and those delayed up to several tens of microseconds were investigated, allowing to observe, for the first time, high-spin excited states above the 16.6 μs isomer. Lifetimes analysis, performed by fast-timing techniques with LaBr3(Ce) scintillators, revealed a difference of almost two orders of magnitude in B(M1) strength for transitions between positive-parity medium-spin yrast states. The data are interpreted by a newly developed microscopic model which takes into account couplings between core excitations (both collective and non-collective) of the doubly magic nucleus 132Sn and the valence proton, using the Skyrme effective interaction in a consistent way. The results point to a fast change in the nature of particle-core excitations with increasing spin.
The inhibitory effect of supraphysiological iodide concentrations on thyroid hormone synthesis (Wolff–Chaikoff effect) and on thyrocyte proliferation is largely known as iodine autoregulation. ...However, the molecular mechanisms by which iodide modulates thyroid function remain unclear. In this paper, we analyze the transcriptome profile of the rat follicular cell lineage PCCl3 under untreated and treated conditions with 10
−
3
M sodium iodide (NaI). Serial analysis of gene expression (SAGE) revealed 84 transcripts differentially expressed in response to iodide (
p
≤
0.001). We also showed that iodide excess inhibits the expression of essential genes for thyroid differentiation:
Tshr,
Nis,
Tg, and
Tpo. Relative expression of 14 of 20 transcripts selected by SAGE was confirmed by real-time PCR. Considering the key role of iodide organification in thyroid physiology, we also observed that both the oxidized form of iodide and iodide per se are responsible for gene expression modulation in response to iodide excess.
This article is devoted to a review of decay properties of excited 0+ states in regions of the nuclear chart well known for shape coexistence phenomena. Even–even isotopes around the Z=20 (Ca), 28 ...(Ni), 50 (Sn), 82 (Pb) proton shell closures and along the Z=36 (Kr), Z=38 (Sr) and Z=40 (Zr) isotopic chains are mainly discussed. The aim is to identify examples of extreme shape coexistence, namely highly deformed structures, well localized in the Potential Energy Surface in the deformation space, which could lead to γ decays substantially hindered. This is in analogy to the 0+ fission shape isomers in the actinides region and to the superdeformed (SD) states at the decay-out spin in medium/heavy mass systems. In this survey, the Hindrance Factor (HF) of the E2 transitions de-exciting 0+ states or SD decay-out states is a primary quantity which is used to differentiate between types of shape coexistence. The 0+ states, examined with the help of the hindrance factor, reveal a multifaceted scenario of shape coexistence. A limited number of 0+ excitations (in the Ni, Sr, Zr and Cd regions) exhibit large HF values (>10), some of which are associated with the clear separation of coexisting wave functions, while in most cases the decay is not hindered, due to the mixing between different configurations. Comparisons with theory predictions based on various models are also presented, some of which shed light on the microscopic structure of the considered states and the origin of the observed hindrances. The impact of shape ensembles at finite temperature on the decay properties of highly-excited states (Giant Dipole Resonances) is also discussed. This research area offers a complementary approach for identifying regions where extreme shape coexistence phenomena may appear.
We investigate the physical properties of compressed gray phosphorus through density functional plus dynamical mean-field theory, showing self-doping and Formula omitted-wave electronic structure ...reconstruction. At commensurate electron density, the Formula omitted spectrum is shown to be almost unaffected by electronic correlations, however upon self-doping largely the normal and superconducting states. These findings provide a microscopic understanding of pressure-induced hole carrier superconductivity on the normal state coherence of Formula omitted-wave superconductors with well-defined Bogoliubov quasiparticles at low temperatures. Upon internal thermalization, the Formula omitted-wave superconducting state loses its phase coherence.
PDF
