Fine structure of the 0.7 MeV resonance in the 230Th neutron--induced cross section

The fine structure of the 0.7 MeV resonance in the 230Th neutron-induced cross section is investigated within the hybrid model. A very good agreement with experimental data is obtained. It is suggested that fine structure of the cross section quantify the changes of the intrinsic states of the nucleus during the disintegration process.Comment: 7 pages, 5 figure

Threshold Resonant Structure of the 232Th Neutron-Induced Fission Cross Section

The structures observed in the sub-threshold neutron-induced fission of ^{232}Th were investigated employing a recent developed model. Theoretical single-particle excitations of a phenomenological two-humped barrier are determined by solving a system of coupled differential equations for the motion along the optimal fission path. A rather good agreement with experimental data was obtained using a small number of independent parameters. It is predicted that the structure at 1.4 and 1.6 MeV is mainly dominated by spin 3/2 partial cross-section with small admixture of spin 1/2, while the structure at 1.7 MeV is given by a large partial cross section of spin 5/2.Comment: 17 pages 11 figure

The Sodium/Proton Exchanger NHE8 Regulates Late Endosomal Morphology and Function

The pH and lumenal environment of intracellular organelles is considered essential for protein sorting and trafficking through the cell. We provide the first evidence that a mammalian sodium (potassium)/proton exchanger, NHE8, plays a key role in the control of protein trafficking and endosome morphology

On a new method in spectroscopy : laser-induced frequency shift of self-excited ion oscillations

Improvements and observations related to a new detection method in plasma spectroscopy based on a laser-induced frequency shift of self-excited ion oscillations were reported. By this method, significant neon absorption signals can be obtained at a very low incident laser power in a self-oscillatory discharge. Absorption spectra in different parts of the self-oscillatory discharge were obtained.Dans cet article on présente des observations et des améliorations apportées à une nouvelle méthode de détection en spectroscopie des plasmas, fondée sur les changements de fréquence des oscillations ioniques dues à une excitation laser résonnante. Par cette méthode on a pu obtenir des signaux d'absorption résonnante du néon à des puissances très basses de la radiation laser incidente. Les spectres d'absorption ont été observés dans les différentes régions de la décharge auto-oscillante

Dynamical single-particle effects in the threshold fission cross section

PACSA new formalism intended to simulate the cross section of the threshold neutron induced fission is proposed. The barriers corresponding to excited intrinsic single-particle states are taken explicitly into account. The radial coupling damping is treated within the Landau–Zener effect while the second-well damping due to re-emission in other channels is treated within an imaginary potential. In this context, the excitations are strongly dependent on the internuclear velocity between the two nascent fragments, and therefore managed by the dynamics of the system. An example of the neutron induced fission cross section of $^{234}$U is given

Sulfatides are required for renal adaptation to chronic metabolic acidosis

Urinary ammonium excretion by the kidney is essential for renal excretion of sufficient amounts of protons and to maintain stable blood pH. Ammonium secretion by the collecting duct epithelia accounts for the majority of urinary ammonium; it is driven by an interstitium-to-lumen NH3 gradient due to the accumulation of ammonium in the medullary and papillary interstitium. Here, we demonstrate that sulfatides, highly charged anionic glycosphingolipids, are important for maintaining high papillary ammonium concentration and increased urinary acid elimination during metabolic acidosis. We disrupted sulfatide synthesis by a genetic approach along the entire renal tubule. Renal sulfatide-deficient mice had lower urinary pH accompanied by lower ammonium excretion. Upon acid diet, they showed impaired ammonuria, decreased ammonium accumulation in the papilla, and chronic hyperchloremic metabolic acidosis. Expression levels of ammoniagenic enzymes and Na(+)-K(+)/NH4(+)-2Cl(-) cotransporter 2 were higher, and transepithelial NH3 transport, examined by in vitro microperfusion of cortical and outer medullary collecting ducts, was unaffected in mutant mice. We therefore suggest that sulfatides act as counterions for interstitial ammonium facilitating its retention in the papilla. This study points to a seminal role of sulfatides in renal ammonium handling, urinary acidification, and acid-base homeostasis