RESUMEN
The decay of (19)O(ß(-)) and (19)Ne(ß(+)) implanted in niobium in its superconducting and metallic phases was measured using purified radioactive beams produced by the SPIRAL GANIL facility. Half-lives and branching ratios measured in the two phases are consistent within a 1σ error bar. This measurement casts strong doubts on the predicted strong electron screening in a superconductor, the so-called superscreening. The measured difference in screening potential energy is 110(90) eV for (19)Ne and 400(320) eV for (19)O. Precise determinations of the half-lives were obtained for (19)O, 26.476(9) s, and for (19)Ne, 17.254(5) s.
RESUMEN
The 02(+) state in 34Si has been populated at the GANIL-LISE3 facility through the ß decay of a newly discovered 1(+) isomer in 34Al of 26(1) ms half-life. The simultaneous detection of e(+)e(-) pairs allowed the determination of the excitation energy E(02(+))=2719(3) keV and the half-life T(1/2)=19.4(7) ns, from which an electric monopole strength of ρ(2)(E0)=13.0(0.9)×10(-3) was deduced. The 2(1)(+) state is observed to decay both to the 0(1)(+) ground state and to the newly observed 0(2)(+) state [via a 607(2) keV transition] with a ratio R(2(1)(+)â0(1)(+)/2(1)(+)â0(2)(+))=1380(717). Gathering all information, a weak mixing with the 0(1)(+) and a large deformation parameter of ß=0.29(4) are found for the 0(2)(+) state, in good agreement with shell model calculations using a new SDPF-U-MIX interaction allowing np-nh excitations across the N=20 shell gap.
RESUMEN
Ischemic stroke is one of the most severe brain pathologies that is extremely difficult to treat. Recently it has been found that acidosis accompanying cerebral ischemia induces activation of acid-sensing ion channel ASIC1a which results in its turn in the neuronal death. Here we present novel derivatives of 3-carboxamidinocoumarines that effectively inhibit ASIC1a and ASIC3 channels in concentration-dependent manner. The most active compound inhibits ASIC1a and ASIC3 channels with corresponding IC50 of 7.3 and 13.2 microM. Our data suggest that 3-carboxamidinocoumarines can be used as a scaffold for novel type of highly efficient anti-ischemic drugs.
Asunto(s)
Benzoatos/síntesis química , Benzopiranos/síntesis química , Diseño de Fármacos , Guanidinas/síntesis química , Proteínas del Tejido Nervioso/antagonistas & inhibidores , Canales Iónicos Sensibles al Ácido , Potenciales de Acción/efectos de los fármacos , Animales , Benzoatos/química , Benzoatos/farmacología , Benzopiranos/química , Benzopiranos/farmacología , Relación Dosis-Respuesta a Droga , Ganglios Espinales/citología , Guanidinas/química , Guanidinas/farmacología , Células HEK293 , Humanos , Estructura Molecular , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Ratas , Canales de SodioRESUMEN
The structure of 44S has been studied by using delayed γ and electron spectroscopy. The decay rates of the 02+ isomeric state to the 2(1)+ and 0(1)+ states, measured for the first time, lead to a reduced transition probability B(E2: 2(1)+â0(2)+)=8.4(26) e(2) fm4 and a monopole strength ρ2(E0: 0(2)+â0(1)+)=8.7(7)×10(-3). Comparisons to shell model calculations point towards prolate-spherical shape coexistence, and a two-level mixing model is used to extract a weak mixing between the two configurations.
RESUMEN
Six proton-emitting states in 19Ne were studied through the inelastic scattering reaction H(19Ne,p);{19}Ne; (p)18F. Their energies and widths were derived from the protons detected at zero degree, while proton-proton angular correlations between the detector at zero degree and a segmented annular detector were used to determine their spin value. In addition to the known states, a new broad J=1/2 resonance has been evidenced at E_{x} approximately 7.9 MeV, approximately 1.45 MeV above the proton emission threshold. By introducing this resonance, the 18F(p,alpha)15O destruction rate in novae is significantly enhanced. This reduces the chance to observe the cosmic gamma-ray emission of 18F from novae in space telescopes.
RESUMEN
The energies of the excited states in very neutron-rich (42)Si and (41,43)P have been measured using in-beam gamma-ray spectroscopy from the fragmentation of secondary beams of (42,44)S at 39A MeV. The low 2(+) energy of (42)Si, 770(19) keV, together with the level schemes of (41,43)P, provides evidence for the disappearance of the Z=14 and N=28 spherical shell closures, which is ascribed mainly to the action of proton-neutron tensor forces. New shell model calculations indicate that (42)Si is best described as a well-deformed oblate rotor.
RESUMEN
A new isomeric 0(+) state was identified as the first excited state in the self-conjugate (N=Z) nucleus 72Kr. By combining for the first time conversion-electron and gamma-ray spectroscopy with the production of metastable states in high-energy fragmentation, the electric-monopole decay of the new isomer to the ground state was established. The new 0(+) state is understood as the band head of the known prolate rotational structure, which strongly supports the interpretation that 72Kr is one of the rare nuclei having an oblate-deformed ground state. This observation gives in fact the first evidence for a shape isomer in a N=Z nucleus.