The neutron-rich Fe isotopes from A = 61 to 66 were studied through multinucleon transfer reactions by bombarding a 238 U target with a 400 MeV 64 Ni beam. Unambiguous identification of prompt γ rays belonging to each nucleus was achieved using coincidence relationships with the ions detected in a high-acceptance magnetic spectrometer. The new data extend our knowledge of the level structure of Fe isotopes, which is discussed in terms of the systematics of the region and compared with large-scale shell-model calculations.

The yrast band of the NϭZ nucleus 84 Mo has been extended up to the 10 ϩ state. Its moment of inertia varies smoothly up to this state ͑rotational frequency 0.6 MeV͒. The new data confirm the systematic delay of the particle alignment frequency in NϭZ nuclei with respect to the neighboring NϾZ nuclei, which has been suggested as a signature of the neutron-proton pairing interaction. Projected shell model calculations performed for the heaviest NϭZ nuclei studied so far, 84 Mo and 88 Ru, predict that the confirmation of a possible enhancement of the neutron-proton residual interaction requires the observation of still higher spins in these nuclei.The study of NϭZ nuclei is expected to give the most relevant information about the properties of the neutronproton (np) pairing interaction. In NϭZ nuclei, neutrons and protons occupy the same shell-model orbitals, and thus can have the largest probability to interact with each other. It has been thought that the np pairing interaction may be the cause of the delayed rotational alignments in the even-even NϭZ nuclei in the Aϳ80 mass region, and this line of research has been actively pursued. The recently observed alignment delays in 72 Kr, 76 Sr, and 80 Zr may be such examples ͓1,2͔.Experimentally, the main difficulty in extending the study of NϭZ nuclei at higher spins is their population with extremely low cross sections in a small number of available reactions. Progress in the development of large ␥-ray arrays and associated ancillary detectors, as well as refinements of the data processing techniques, allowed recent advance in the knowledge of the heaviest NϭZ nuclei in general, and of their high spin behavior in particular. Theoretically, it has been suggested that the behavior of the moment of inertia of an NϭZ nucleus with increasing spin ͑rotation͒ would be particularly relevant in this respect. Different pairing fields (nn, pp, and np) respond differently to the Coriolis forces. The enhancement of the np interaction in NϭZ nuclei has in general an effect to sustain the pairing field under rotation. The real situation is, however, rather complicated, due to the fact that the spin alignment is also sensitively influenced by other factors such as deformation. Theoretical calculations, most of which are still schematic, have reached various conclusions on the role of different np interactions ͓3-9͔.To date, consistent delays in the crossing frequencies ͑due to alignment of the g 9/2 particles͒ in the ground state bands have been observed for the NϭZ Kr ͓1,2͔, Sr, Zr ͓2͔, and Ru ͓10͔ nuclei. The strongest effect has been observed in 72 Kr where a very delayed crossing has been located at 0.85 MeV ͓2͔. In 76 Sr there is a discernible effect which indicates a broad crossing shifted to 0.62 MeV ͑compared to Ϸ0.55 in NϾZ isotopes ͓2͔͒, while for 80 Zr ͓2͔ and 88 Ru ͓10͔ the observations indicate again a delay but the crossing has not been located yet. In this chain of NϭZ nuclei, 84 Mo is the only one which has not been studied at spins higher than 4ប.In view of the pre...

A new sensitive and fast quantitative analytical method for the simultaneous determination of clopidogrel, its main metabolite clopidogrel carboxylic acid, and the newly described acyl glucuronide metabolite, in human plasma samples, is presented. The analytical procedures (plasma storage, handling, and extract storage in the autosampler) were optimized in order to avoid back-conversion; a known drawback in measurements of clopidogrel. Clopidogrel acyl glucuronide was confirmed as a major source of back-conversion to the parent drug in the presence of methanol, and thorough stability experiments were carried out to find the most appropriate conditions for an accurate analysis of clopidogrel and the two metabolites. The method was validated by assessing selectivity, sensitivity, linearity, accuracy, and precision for all three analytes, in accordance to Food and Drug Administration guidelines. Spiked quality controls in plasma as well as incurred samples were used to verify back-conversion in the selected conditions, with results meeting European Medicines Agency acceptance criteria (concentrations within 80-120% of the first reading). The method was then applied to a pharmacokinetic study, and for the first time, a pharmacokinetic curve of clopidogrel acyl glucuronide in human plasma is presented. The concentrations ranged up to 1,048.684 ng/mL, with a mean of 470.268 ng/mL, while clopidogrel had a mean C(max) of 1.348 ng/mL; these orders of magnitude show how much the back-conversion of this metabolite may influence clopidogrel quantification if it is not properly controlled.

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