Glibenclamide attenuates brain edema associated with microglia activation after intracerebral hemorrhage.

OBJECTIVE: Glibenclamide, Sulfonylurea receptor 1 antagonist, reduces brain edema after cerebral hemorrhage. However, the effects of glibenclamide on microglial activation and inflammatory cell infiltration after cerebral hemorrhage are unclear. The present study investigated the effect of glibenclamide on microglial activation and inflammatory cell infiltration in a rat cerebral hemorrhage model. METHODS: A collagenase intracerebral injection model was used to cause cerebral hemorrhage in rats. After injury, glibenclamide was continuously administered at 1.0µL/h for 24hours. We evaluated hematoma volume, brain edema, expression of ABCC8, galectin-3 and CD11b, and anti-Iba-1 antibody staining. RESULTS: Glibenclamide significantly reduced water content. Meanwhile, glibenclamide significantly reduced expression of galectin-3 and CD11b in the cerebral cortex and putamen on the bleeding side. Immunohistochemical staining confirmed that glibenclamide attenuated activation of microglia around the hematoma. CONCLUSIONS: Glibenclamide reduced microglial activation and infiltration of inflammatory cells, resulting in amelioration of cerebral edema.

Inelastic and quasi-elastic neutron scattering spectrometers in J-PARC.

J-PARC, Japan Proton Accelerator Research Complex provides short pulse proton beam at a repetition rate 25Hz and the maximum power is expected to be 1MW. Materials and Life Science Experimental Facility (MLF) has 23 neutron beam ports and 21 instruments have already been operated or under construction/commissioning. There are 6 inelastic/quasi-elastic neutron scattering spectrometers and the complementary use of these spectrometers will open new insight for life science. This article is part of a Special Issue entitled "Science for Life" Guest Editor: Dr. Austen Angell, Dr. Salvatore Magazù and Dr. Federica Migliardo.

Spin excitations in hole-overdoped iron-based superconductors.

Understanding the overall features of magnetic excitation is essential for clarifying the mechanism of Cooper pair formation in iron-based superconductors. In particular, clarifying the relationship between magnetism and superconductivity is a central challenge because magnetism may play a key role in their exotic superconductivity. BaFe2As2 is one of ideal systems for such investigation because its superconductivity can be induced in several ways, allowing a comparative examination. Here we report a study on the spin fluctuations of the hole-overdoped iron-based superconductors Ba1-xKxFe2As2 (x = 0.5 and 1.0; Tc = 36 K and 3.4 K, respectively) over the entire Brillouin zone using inelastic neutron scattering. We find that their spin spectra consist of spin wave and chimney-like dispersions. The chimney-like dispersion can be attributed to the itinerant character of magnetism. The band width of the spin wave-like dispersion is almost constant from the non-doped to optimum-doped region, which is followed by a large reduction in the overdoped region. This suggests that the superconductivity is suppressed by the reduction of magnetic exchange couplings, indicating a strong relationship between magnetism and superconductivity in iron-based superconductors.

Phonons of Fe-based superconductor Ca10Pt4As8(Fe1-x Pt x As)10.

We report the results of inelastic neutron scattering measurements on particular phonons of a superconducting (SC) Ca10Pt4As8(Fe1-x Pt x As)10 with the onset transition temperature T c ~ 33 K to investigate mainly what roles orbital fluctuation plays in Cooper pairing, where we observed a slight softening of the in-plane transverse acoustic mode corresponding to the elastic constant C 66. This softening starts at temperature T well above the SC T c, as T decreases. An anomalously strong change of the scattering intensity of in-plane optical modes was observed at the M point of the pseudo tetragonal reciprocal space in the range of 35 < ω < 40 meV with decreasing T from far above T c. Because this ω region mainly corresponds to the motion of Fe and As atoms in the FeAs planes, the finding presents information on the coupling between the orbital fluctuation of Fe 3d electrons and the lattice system, useful for studying the possible roles of orbital fluctuation in the pairing mechanism and/or the appearance of the so-called nematic phase.

High-energy spin and charge excitations in electron-doped copper oxide superconductors.

The evolution of electronic (spin and charge) excitations upon carrier doping is an extremely important issue in superconducting layered cuprates and the knowledge of its asymmetry between electron- and hole-dopings is still fragmentary. Here we combine X-ray and neutron inelastic scattering measurements to track the doping dependence of both spin and charge excitations in electron-doped materials. Copper L3 resonant inelastic X-ray scattering spectra show that magnetic excitations shift to higher energy upon doping. Their dispersion becomes steeper near the magnetic zone centre and they deeply mix with charge excitations, indicating that electrons acquire a highly itinerant character in the doped metallic state. Moreover, above the magnetic excitations, an additional dispersing feature is observed near the Γ-point, and we ascribe it to particle-hole charge excitations. These properties are in stark contrast with the more localized spin excitations (paramagnons) recently observed in hole-doped compounds even at high doping levels.

Unconventional ferroelectric transition in the multiferroic compound TbMnO3 revealed by the absence of an anomaly in c-polarized phonon dispersion.

TbMnO(3) exhibits a spontaneous electric polarization along c concomitantly with a spiral spin ordering modulated along b below T_{C} = 28 K. We have performed inelastic x-ray scattering measurements on a single crystal of TbMnO(3) to clarify whether phonon anomalies related to the ferroelectricity exist. We measured transverse modes, especially the Mn-O-Mn bending mode polarized along c and propagating along b, which we expect is most relevant to the ferroelectricity. However, no anomaly was found in the phonon dispersion below 50 meV across T_{C}. The present result suggests that the mechanism of ferroelectricity in TbMnO(3) is different from that of a conventional displacive-type ferroelectric. The weak coupling between electric polarization and lattice in TbMnO(3) strongly suggests that the ferroelectricity is mainly derived from the spiral spin ordering.

Commensurate-incommensurate crossover of charge stripe in La2-xSrxNiO4 (x approximately 1/3).

The temperature (T) dependence of the charge-stripe order in La2-xSrxNiO4 has been investigated in the vicinity of x approximately 1/3 by synchrotron radiation x-ray diffraction measurements. With decreasing T, a prominent commensurate-incommensurate (C-IC) crossover is observed in the x<1/3 region, while for the x>1/3 region the IC order is dominant over the whole T range. Such a C-IC crossover is interpreted as the entropy-driven self-doping of the charge stripes, and its x dependence indicates the clear electron-hole asymmetry with the x=1/3 compound as the Mott insulator.