Transient jitter from injection in storage rings

10.1103/PhysRevSTAB.12.091001Physical Review Special Topics - Accelerators and Beams1299100

Visualizing 11^{11}N by resonance reactions

International audienceThe proton-rich, unbound nucleus 11N has been studied using the technique of elastic resonance scattering in inverse geometry. The spins and parities of the three lowest resonance levels have been determined as 1/2+, 1/2− and 5/2+, resulting from the orbitals 1s1/2, 0p1/2 and 0d5/2, respectively. This level ordering is the same as the one found in the mirror nucleus of 11N, namely the one-neutron halo nucleus 11Be. Especially, the in 11Be well known level inversion, where the ground state is a 1/2+ intruder state below the from a naive shell model expected ground state 1/2−, is also found in 11N

Actin-based dynamics during spermatogenesis and its significance*

Actin can be found in all kinds of eukaryotic cells, maintaining their shapes and motilities, while its dynamics in sperm cells is understood less than their nonmuscle somatic cell counterparts. Spermatogenesis is a complicated process, resulting in the production of mature sperm from primordial germ cell. Significant structural and biochemical changes take place in the seminiferous epithelium of the adult testis during spermatogenesis. It was proved that all mammalian sperm contain actin, and that F-actin may play an important role during spermatogenesis, especially in nuclear shaping. Recently a new model for sperm head elongation based on the acrosome-acroplaxome-manchette complex has been proposed. In Drosophila, F-actin assembly is supposed to be very crucial during individualization. In this mini-review, we provide an overview of the structure, function, and regulation characteristics of actin cytoskeleton, and a summary of the current status of research of actin-based structure and movement is also provided, with emphasis on the role of actins in sperm head shaping during spermiogenesis and the cell junction dynamics in the testis. Research of the Sertoli ectoplasmic specialization is in the spotlight, which is a testis-specific actin-based junction very important for the movement of germ cells across the epithelium. Study of the molecular architecture and the regulating mechanism of the Sertoli ectoplasmic specialization has become an intriguing field. All this may lead to a new strategy for male infertility and, at the same time, a novel idea may result in devising much safer contraception with high efficiency. It is hoped that the advances listed in this review would give developmental and morphological researchers a favorable investigating outline and could help to enlarge the view of new strategies and models for actin dynamics during spermatogenesis