Effects of mirogabalin, a novel ligand for the α2δ subunit of voltage-gated calcium channels, on N-type calcium channel currents of rat dorsal root ganglion culture neurons.

Mirogabalin, which is a novel ligand for the α2δ subunit of voltage-gated calcium channels, is being developed for treating neuropathic pain including diabetic peripheral neuropathy and postherpetic neuralgia. Mirogabalin possesses unique α2δ subunit binding characteristics and has potent and long-lasting analgesic effects in neuropathic pain models. In the present study, we investigated the effects of mirogabalin on N-type calcium channel currents of the rat dorsal root ganglion (DRG) culture neurons using the whole-cell patch clamp technique. Small or medium DRG neurons were isolated from Sprague-Dawley rats and were incubated for 20 to 24 h with mirogabalin or pregabalin. The DRG neurons were depolarised from a holding potential of -40 mV to +40 mV in steps of 10 mV for 220 ms, and elicited N-type calcium channel currents were recorded. The N-type calcium channel currents were verified by sensitivity to ω-conotoxin GVIA, a selective N-type calcium channel blocker. Mirogabalin inhibited the calcium channel currents of rat DRG neurons at 50 µM, and pregabalin inhibited them at 200 µM. Mirogabalin and pregabalin showed significant differences in the peak current densities at depolarisation to -20 and -10 mV when compared with that shown by the vehicle control. In conclusion, mirogabalin inhibits N-type calcium channel currents in rat DRG culture neurons. The potent and long-lasting analgesic effects of mirogabalin are thought to be associated with its potent and selective binding to α2δ-1 subunits and following functional inhibition of calcium channel currents.

Quantitative Characterization of the Nanoscale Local Lattice Strain Induced by Sr Dopants in La_{1.92}Sr_{0.08}CuO_{4}.

The nanometer scale lattice deformation brought about by the dopants in the high temperature superconducting cuprate La_{2-x}Sr_{x}CuO_{4} (x=0.08) was investigated by measuring the associated x-ray diffuse scattering around multiple Bragg peaks. A characteristic diffuse scattering pattern was observed, which can be well described by continuum elastic theory. With the fitted dipole force parameters, the acoustic-type lattice deformation pattern was reconstructed and found to be of similar size to lattice thermal vibration at 7 K. Our results address the long-term concern of dopant introduced local lattice inhomogeneity, and show that the associated nanometer scale lattice deformation is marginal and cannot, alone, be responsible for the patched variation in the spectral gaps observed with scanning tunneling microscopy in the cuprates.

Scaling of Memories and Crossover in Glassy Magnets.

Glassiness is ubiquitous and diverse in characteristics in nature. Understanding their differences and classification remains a major scientific challenge. Here, we show that scaling of magnetic memories with time can be used to classify magnetic glassy materials into two distinct classes. The systems studied are high temperature superconductor-related materials, spin-orbit Mott insulators, frustrated magnets, and dilute magnetic alloys. Our bulk magnetization measurements reveal that most densely populated magnets exhibit similar memory behavior characterized by a relaxation exponent of [Formula: see text]. This exponent is different from [Formula: see text] of dilute magnetic alloys that was ascribed to their hierarchical and fractal energy landscape, and is also different from [Formula: see text] of the conventional Debye relaxation expected for a spin solid, a state with long range order. Furthermore, our systematic study on dilute magnetic alloys with varying magnetic concentration exhibits crossovers among the two glassy states and spin solid.

Large topological Hall effect in a short-period helimagnet MnGe.

We have observed an unconventional, likely topological, Hall effect over a wide temperature region in the magnetization process of a chiral-lattice helimagnet MnGe. The magnitude of the topological Hall resistivity is nearly temperature-independent below 70 K, which reflects the real-space fictitious magnetic field proportional to a geometric quantity (scalar spin chirality) of the underlying spin texture. From the neutron diffraction study, it is anticipated that a relatively short-period (3-6 nm) noncoplanar spin structure is stabilized from the proper screw state in a magnetic field to produce the largest topological Hall response among the B20-type (FeSi-type) chiral magnets.

Imaging doped holes in a cuprate superconductor with high-resolution Compton scattering.

The high-temperature superconducting cuprate La(2-x)Sr(x)CuO(4) (LSCO) shows several phases ranging from antiferromagnetic insulator to metal with increasing hole doping. To understand how the nature of the hole state evolves with doping, we have carried out high-resolution Compton scattering measurements at room temperature together with first-principles electronic structure computations on a series of LSCO single crystals in which the hole doping level varies from the underdoped (UD) to the overdoped (OD) regime. Holes in the UD system are found to primarily populate the O 2p(x)/p(y) orbitals. In contrast, the character of holes in the OD system is very different in that these holes mostly enter Cu d orbitals. High-resolution Compton scattering provides a bulk-sensitive method for imaging the orbital character of dopants in complex materials.

Multiferroic M-type hexaferrites with a room-temperature conical state and magnetically controllable spin helicity.

Magnetic and magnetoelectric (ME) properties have been studied for single crystals of Sc-doped M-type barium hexaferrites. Magnetization (M) and neutron diffraction measurements revealed that by tuning Sc concentration a longitudinal conical state is stabilized up to above room temperatures. ME measurements have shown that a transverse magnetic field (H) can induce electric polarization (P) at lower temperatures and that the spin helicity is nonvolatile and endurable up to near the conical magnetic transition temperature. It was also revealed that the response (reversal or retention) of the P vector upon the reversal of M varies with temperature. In turn, this feature allows us to control the relation between the spin helicity and the M vectors with H and temperature.

Magnetic-field-induced polarization flop in multiferroic TmMn2O5.

We discovered a reversible electric polarization flop from the a axis (P(a)) to the b axis (P(b)) in multiferroic TmMn2O5 below 5 K by applying a magnetic field of approximately 0.5 T along the c axis. This phenomenon is the first example of the rare-earth (R) compound RMn2O5. This magnetic-field-induced polarization flop corresponds to a magnetic phase transition from one incommensurate magnetic (ICM) P(a) phase to another ICM P(b) phase, which is equivalent to an ICM P(b) phase above 5 K under no magnetic field. The spin chirality in the bc plane, which was observed in the P(b) phase by polarized neutron diffraction, disappeared in the ICM P(a) phase. This indicates that the polarization in the ICM phases of TmMn2O5 was induced by an S(i) x S(j)-type interaction.

Charge excitations in the stripe-ordered La5/3Sr1/3NiO4 and La2-x(Ba,Sr)xCuO4 superconducting compounds.

Charge excitations in stripe-ordered 214 compounds La_{5/3}Sr_{1/3}NiO_{4} and 1/8-doped La2-x(Ba or Sr)xCuO4 are studied using resonant inelastic x-ray scattering in the hard x-ray regime. We observe = or approximately 1 eV excitation with a momentum transfer corresponding to the charge stripe spatial period both for the diagonal (nickelate) and parallel (cuprates) stripes. They are interpreted as collective stripe excitations or anomalous softening of the charge excitonic modes of the in-gap states.

Magnetic dispersion of the diagonal incommensurate phase in lightly doped La2-xSrxCuO4.

We present inelastic neutron scattering experiments on a single-domain crystal of lightly doped La1.96Sr0.04CuO4. We find that the magnetic excitation spectrum in this insulating phase with a diagonal incommensurate spin modulation is remarkably similar to that in the superconducting regime, where the spin modulation is bond parallel. In particular, we find that the dispersion slope at low energy is essentially independent of doping and temperature over a significant range. The energy at which the excitations cross the commensurate antiferromagnetic wave vector increases roughly linearly with doping through the underdoped regime.

Absence of broken time-reversal symmetry in the pseudogap state of the high temperature La(2-x)SrxCuO4 superconductor from muon-spin-relaxation measurements.

We have performed zero-field muon-spin-relaxation measurements on single crystals of La(2-x)SrxCuO4 to search for spontaneous currents in the pseudogap state. By comparing measurements on materials across the phase diagram, we put strict upper limits on any possible time-reversal symmetry breaking fields that could be associated with the pseudogap. Comparison between experimental limits and the proposed circulating current states effectively eliminates the possibility that such states exist in this family of materials.

Observation of a 500 meV collective mode in La2-xSrxCuO4 and Nd2CuO4 using resonant inelastic X-ray scattering.

Utilizing resonant inelastic x-ray scattering, we report a previously unobserved mode in the excitation spectrum of La2-xSrxCuO4 and Nd2CuO4 at 500 meV. The mode is peaked around the (pi, 0) point in reciprocal space and is observed to soften, and broaden, away from this point. Samples with x=0, 0.01, 0.05, and 0.17 were studied. The new mode is found to be rapidly suppressed with increasing Sr content and is absent at x=0.17, where it is replaced by a continuum of excitations. This mode is only observed when the incident x-ray polarization is normal to the CuO planes.

Disappearance of antiferromagnetic spin excitations in overdoped La2-xSrxCuO4.

Magnetic excitations for energies up to approximately 100 meV are studied for overdoped La(2-x)Sr(x)CuO(4) with x=0.25 and 0.30, using time-of-flight neutron spectroscopy. Comparison of spectra integrated over the width of an antiferromagnetic Brillouin zone demonstrates that the magnetic scattering at intermediate energies, 20

Direct relation between the low-energy spin excitations and superconductivity of overdoped high-Tc superconductors.

The dynamic spin susceptibility, chi(")(omega), has been measured over the energy range of 2

Field-induced thermal metal-to-insulator transition in underdoped La(2-x)Sr(x)CuO(4+delta).

The transport of heat and charge in cuprates was measured in single crystals of La(2-x)Sr(x)CuO(4+delta) (LSCO) across the doping phase diagram at low temperatures. In underdoped LSCO, the thermal conductivity is found to decrease with increasing magnetic field in the T-->0 limit, in striking contrast to the increase observed in all superconductors, including cuprates at higher doping. In heavily underdoped LSCO, where superconductivity can be entirely suppressed with an applied magnetic field, we show that a novel thermal metal-to-insulator transition takes place upon going from the superconducting state to the field-induced normal state.

Resonant inelastic x-ray scattering study of charge excitations in La(2)CuO(4).

We report a resonant inelastic x-ray scattering study of the dispersion relations of charge-transfer excitations in insulating La(2)CuO(4).. These data reveal two peaks, both of which show two-dimensional characteristics. The lowest energy excitation has a gap energy of approximately 2.2 eV at the zone enter, and a dispersion of approximately 1 eV. The spectral weight of this mode becomes dramatically smaller around (pi, pi). The second peak shows a smaller dispersion ( approximately 0.5 eV) with a zone-center energy of approximately 3.9 eV. We argue that these are both highly dispersive exciton modes damped by the presence of the electron-hole continuum.

Genistein, a soybean isoflavone, affects bone marrow lymphopoiesis and prevents bone loss in castrated male mice.

Soybean isoflavones exhibit selective effects on bone metabolism in postmenopausal women as well as in ovariectomized animals. Recently, the role of estrogen in bone metabolism in men has also received attention, because a man with a mutated estrogen receptor-alpha (ER(alpha)) gene will exhibit osteoporotic phenotypes. To examine the possible role of genistein, a soybean isoflavone, in bone marrow hemopoiesis and bone metabolism in men, male mice were orchidectomized (orx) and treated with genistein (0.4-0.8 mg/day) or 17beta-estradiol (E(2); 0.03 microg/day) subcutaneously for 3 weeks. In orx mice, seminal vesicle weight decreased markedly, and it was not affected by the administration of genistein or E(2). The number of bone marrow cells was markedly increased after orx, and the majority was B-220 weakly positive pre-B cells. Increased B-lymphopoiesis was restored completely by E(2) or genistein administration. In orx mice, bone mineral density of the femur decreased markedly, and this bone loss was prevented to a significant extent by treatment with genistein as well as E(2). Histomorphometry showed that the trabecular bone volume in the femoral distal metaphysis decreased markedly after orx, and genistein and E(2) prevented this bone loss. These results suggest that soybean isoflavones prevent bone loss due to androgen deficiency in males.

Optical response of high-dielectric-constant perovskite-related oxide.

Optical conductivity measurements on the perovskite-related oxide CaCu3Ti4O12 provide a hint of the physics underlying the observed giant dielectric effect in this material. A low-frequency vibration displays anomalous behavior, implying that there is a redistribution of charge within the unit cell at low temperature. At infrared frequencies (terahertz), the value for the dielectric constant is approximately 80 at room temperature, which is far smaller than the value of approximately 10(5) obtained at lower radio frequencies (kilohertz). This discrepancy implies the presence of a strong absorption at very low frequencies due to dipole relaxation. At room temperature, the characteristic relaxation times are fast (less than or approximately 500 nanoseconds) but increase dramatically at low temperature, suggesting that the large change in dielectric constant may be due to a relaxor-like dynamical slowing down of dipolar fluctuations in nanosize domains.

Soft mode dynamics above and below the Burns temperature in the relaxor Pb(Mg1/3Nb2/3)O3.

We report neutron inelastic scattering measurements of the lowest-energy transverse optic (TO) phonon branch in the relaxor Pb(Mg1/3Nb2/3)O3 from 400 to 1100 K. Far above the Burns temperature T(d) approximately 620 K we observe well-defined propagating TO modes at all wave vectors q, and a zone center TO mode that softens in a manner consistent with that of a ferroelectric soft mode. Below T(d) the zone center TO mode is overdamped. This damping extends up to, but not above, the waterfall wave vector q(wf), which is a measure of the average size of the polar nanoregions.

Identification of viruses infected in Rehmannia glutinosa Libosch. var purpurea Makino and effect of virus infection on root yield and iridoid glycoside contents.

Virus free plants of Rehmannia glutinosa Libosch. var. purpurea Makino were obtained through meristem tip tissue cultures from plants infected with a mixture of tabocco mosaic virus(TMV), a member of the carlavirus group, and an unknown spherical virus. The re-infection rate of the virus free plants by TMV in the field was determined by enzyme linked immunosorbent assay(ELISA). Twenty seven percent of the plants were re-infected during the first year, 31 % by the end of second year, and 63 % by the end of the third year. The yield of root and iridoid glycoside contents gradually decreased each year. These results led to the conclusion that virus infection causes marked decrease of the yield of roots and productivity of secondary metabolites.