Interaction of Cupidin/Homer2 with two actin cytoskeletal regulators, Cdc42 small GTPase and Drebrin, in dendritic spines

Background  

Homer is a postsynaptic scaffold protein that links various synaptic signaling proteins, including the type I metabotropic glutamate receptor subunits 1α and 5, the inositol 1,4,5-trisphosphate receptor, Shank and Cdc42 small GTPase. Overexpression of Homer induces changes in dendritic spine morphology in cultured hippocampal neurons. However, the molecular basis underpinning Homer-mediated spine morphogenesis remains unclear. In this study, we aimed to elucidate the structural and functional properties of the interaction between Cupidin/Homer2 and two actin-cytoskeletal regulators, Cdc42 small GTPase and Drebrin.     

Superparamagnetic behavior of iron oxides supported on porous silica gels

Spinel iron oxide (Fe₃O₄-γ-Fe₂O₃) particles were supported on microbeads of silica gel by the calcination of the silica gel base adsorbing citric acid and Fe³⁺ ions. The X-ray diffraction patterns and the⁵⁷Fe Mössbauer spectra measured for the spinel iron oxide indicated that the particle size of the oxide was regulated by the mean pore diameter (4–82 nm) of the silica gel support employed. In the case of α-Fe₂O₃ particles prepared by using the same silica gel beads, it was revealed by the Mössbauer spectra and the electron micrographs that there were relatively large particles of the oxide on the surface of the beads, in addition to the particles in the silica gel micropores.     

An experimental study of non-equilibrium vapour condensation in a shock-tube

Filmwise non-equilibrium condensation of methanol vapour is investigated on a shock-tube endwall behind a reflected shock wave. The theoretical prediction of a transition phenomenon during the growth of a liquid film is experimentally demonstrated: the film grows approximately in proportion to the time at the early stages after the reflection of the shock wave and, after a transition period, it grows in proportion to the square root of the time. The condensation parameter of the vapour is obtained from the conformity between experiment and theory. It is found that the condensation parameter of the methanol vapour is of the magnitude of one tenth of the value for the complete capture of the molecules on the liquid surface.     

L-Malate-sensing electrode based on malate dehydrogenase and NADH oxidase

An L-malate-sensing electrode was constructed from an oxygen electrode and a layer containing immobilized malate dehydrogenase (MDH) and NADH oxidase. MDH catalyses the dehydrogenation of L-malate by NAD⁺ and NADH oxidase catalyses the regeneration of NAD⁺ with the use of oxygen. The regeneration enables the L-malate oxidation to proceed efficiently even in a medium of neutral pH. At pH 8.0, L-malate in the concentration range 5 μM–1.5 mM can be measured. The relative standard deviation for the measurement is 1.2% (L-malate concentration, 0.2 mM; n=10). The present L-malate-sensing electrode is stable for 8 weeks. A two-electrode sensor system consisting of the L-malate-sensing electrode and an L-lactate-sensing electrode based on lactate oxidase was prepared and applied to the simultaneous determination of the two components in wines.     

High-energy multiple muons viewed from the observation of gamma-ray families at mountain altitudes

Summary Based on the knowledge of the nature of primary cosmic rays inferred from the observations of gamma-ray family events with the largescale emulsion chamber experiments at Mt. Fuji and at Mt. Kanbala, the three-dimensional Monte Carlo simulation on the high-energy multiple-muon events has been carried out. By comparing the simulation results with the presently available observed ones, it is concluded that the hypothesis for the composition of primary cosmic rays being heavy-nuclei dominant, given from the analysis of gamma-ray family events, is quite consistent with the observed results on the lateral spread of multiple-muon events.

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Riassunto Si effettua la simulazione di Monte Carlo tridimensionale sugli eventi di muoni multipli ad alta energia, basandosi sulla conoscenza della natura dei raggi cosmici primari inferita dalle osservazioni degli eventi della famiglia di raggi gamma con gli esperimenti su larga scala della camera ad emulsione sul Monte Fuji e sul Monte Kanbala. Confrontando i risultati della simulazione con quelli osservati attualmente disponibili, si conclude che l'ipotesi della composizione dei raggi cosmici primari in cui predominano i nuclei pesanti, data dall'analisi degli eventi della famiglia di raggi gamma, risulta del tutto coerente con i risultati osservati sulla diffusione laterale degli eventi a muoni multipli.