PubMed Health⌕ Search

Biomedical subjects

D Curien

Publications and source records attributed to D Curien.

17 recordsLinked to original sources
PubMed2006

Observation of 54Ni: cross-conjugate symmetry in f7/2 mirror energy differences.

Gamma decays from excited states up to Jpi=6+ in the N=Z-2 nucleus 54Ni have been identified for the first time. Level energies are compared with those of the isobars 54Co and 54Fe and of the cross-conjugate nuclei of mass A=42. The good but puzzling f7/ cross-conjugate symmetry in mirror and triplet energy differences is analyzed. Shell model calculations reproduce the new data but the necessary nuclear charge-dependent phenomenology is not fully explained by modern nucleon-nucleon potentials.

Journal Article↗
PubMed2006

Island of rare Earth nuclei with tetrahedral and octahedral symmetries: possible experimental evidence.

Calculations using realistic mean-field methods suggest the existence of nuclear shapes with tetrahedral Td and/or octahedral Oh symmetries sometimes at only a few hundreds of keV above the ground states in some rare earth nuclei around 156Gd and 160Yb. The underlying single-particle spectra manifest exotic fourfold rather than Kramers's twofold degeneracies. The associated shell gaps are very strong, leading to a new form of shape coexistence in many rare earth nuclei. We present possible experimental evidence of the new symmetries based on the published experimental results--although an unambiguous confirmation will require dedicated experiments.

Journal Article↗
PubMed2006

Transition probabilities in 134Pr: a test for chirality in nuclear systems.

Exited states in 134Pr were populated in the fusion-evaporation reaction 119Sn(19F,4n)134Pr. Recoil distance Doppler-shift and Doppler-shift attenuation measurements using the Euroball spectrometer, in conjunction with the inner Bismuth Germanate ball and the Cologne plunger, were performed at beam energies of 87 MeV and 83 MeV, respectively. Reduced transition probabilities in 134Pr are compared to the predictions of the two quasiparticle + triaxial rotor and interacting boson fermion-fermion models. The experimental results do not support the presence of static chirality in 134Pr underlying the importance of shape fluctuations. Only within a dynamical context the presence of intrinsic chirality in 134Pr can be supported.

Journal Article↗
PubMed2004

Compound and rotational damping in warm deformed rare-earth nuclei.

The gamma decay in the quasicontinuum from selected configurations of the rotational nucleus 163Er has been measured with the EUROBALL array. A new analysis technique has allowed for the first time to directly measure the compound and rotational damping widths Gamma (micro) and Gamma (rot). Values of Gamma (micro) approximately 20 keV and Gamma (rot) approximately 200 keV are obtained in the spin region I approximately 30-40 variant Planck's over 2pi, in good agreement with microscopic cranked shell model calculations. A dependence of Gamma (micro) and Gamma (rot) on the K-quantum number of the nuclear states is also presented.

Journal Article↗
PubMed2002

Evidence for second-phonon nuclear wobbling.

The nucleus 163Lu has been populated through the reaction 139La(29Si,5n) with a beam energy of 157 MeV. Three triaxial, strongly deformed (TSD) bands have been observed with very similar rotational properties. The first excited TSD band has earlier been assigned as a one-phonon wobbling excitation built on the lowest-lying (yrast) TSD band. The large B(E2)(out)/B(E2)(in) value obtainable for one of four observed transitions between the second and first excited TSD bands is in good agreement with particle-rotor calculations for a two-phonon wobbling excitation.

Journal Article↗
PubMed2001

Evidence for the wobbling mode in nuclei.

The nucleus (163)Lu has been populated through the fusion-evaporation reaction (139)La((29)Si,5n)(163)Lu with a beam energy of 152 MeV. The electromagnetic properties of several connecting transitions between two presumably triaxial, strongly deformed (TSD) bands have been studied. Evidence is presented for the assignment of the excited TSD band as a wobbling mode built on the yrast TSD band, based on comparisons to new calculations in which an aligned particle is coupled to a strongly deformed triaxial rotor. The wobbling mode is uniquely related to triaxiality in nuclei.

Journal Article↗
PubMed1987

[24-hour efficacy of a system of transcutaneous administration of nitroglycerin. Evaluation by the exercise test and gamma angiography].

The effects of a nitroglycerin transdermal therapeutic system (TTS NG 10 mg/24 h) 24 hours after application were evaluated by exercise left ventricular radionuclide cineangiography. 20 patients with ischemic heart disease were included in a double-blind, within patient, acute study comparing TTS NG to placebo. Were measured: exercise-test parameters and global (EF) and regional (rEF) ejection fractions at rest and during exercise. At maximum load, the double product rose from 18,680 +/- 4,118 with placebo to 21,538 +/- 3,988 with TTs NG (p less than 0.01) and ST-segment depression at same load decreased from 2.6 +/- 0.7 mm with placebo to 1.0 +/- 0.7 mm with TTS NG (p less than 0.001). Exercise EF increased from 0.57 +/- 0.15 with placebo to 0.63 +/- 0.12 with TTS NG (p less than 0.001) and was higher at exercise than at rest. Two hypokinetic territories improved during exercise with TTS NG: basal rEF increased to 0.45 +/- 0.07 with TTS NG versus 0.31 +/- 0.13 with placebo (p less than 0.01); anteroseptal rEF increased to 0.49 +/- 0.14 versus 0.43 +/- 0.14 with placebo (p 0.05); no significant improvement was observed in anterolateral and inferior territories were previous myocardial infarction occurred predominantly. These data demonstrate the 24 hours efficacy of this new galenic form of TTS NG in ischemic heart disease on exercise test parameters. TTS NG improving predominantly regional kinetics of ischemic but non infarcted territories and thus improving EF at exercise.

Administration, Cutaneous↗