Nonmagnetic Ground State in RuO_{2} Revealed by Muon Spin Rotation.

The magnetic ground state of single crystalline RuO_{2} was investigated by the muon spin rotation and relaxation (µSR) experiment. The spin precession signal due to the spontaneous internal magnetic field B_{loc}, which is expected in the magnetically ordered phase, was not observed in the temperature range 5-400 K. Muon sites were evaluated by first-principles calculations using dilute hydrogen simulating muon as pseudohydrogen, and B_{loc} was simulated for the antiferromagnetic structures with a Ru magnetic moment |m_{Ru}|≈0.05µ_{B} suggested from diffraction experiments. As a result, the possibility was ruled out that muons are localized at sites where B_{loc} accidentally cancels. Conversely, assuming that the slow relaxation observed in µSR spectra was part of the precession signal, the upper limit for the magnitude of |m_{Ru}| was estimated to be 4.8(2)×10^{-4}µ_{B}, which is significantly less than 0.05µ_{B}. These results indicate that the antiferromagnetic order, as reported, is unlikely to exist in the bulk crystal.

Superconducting pairing and the pseudogap in the nematic dynamical stripe phase of La2-xSrxCuO4.

Fully absorption coefficient corrected Raman spectra were obtained in La2-xSrxCuO4. The B1g spectra have a Fleury-Loudon type two-magnon peak (resonant term) whose energy decreases from 3180 cm(-1) (394 meV) to 440 cm(-1) (55 meV) on increasing the carrier density from x = 0 to 0.25, while the B2g spectra have a 1000-3500 cm(-1) (124-434 meV) hump (hill) whose lower-edge energy increases from x = 0 to 0.115 and then stays constant to x = 0.25. The B2g hump is assigned to the electronic scattering (non-resonant term) of the spectral function with magnetic self-energy. The completely different carrier density dependence arises from anisotropic magnetic excitations of spin-charge stripes. The B1g spectra were assigned to the sum of k âˆ¥  and k⊥ stripe excitations and the B2g spectra to k⊥ stripe excitations according to the calculation by Seibold and Lorenzana (2006 Phys. Rev. B 73 144515). The k âˆ¥  and k⊥ stripe excitations in fluctuating spin-charge stripes were separately detected for the first time. The appearance of only k⊥ stripe excitations in the electronic scattering arises from the charge hopping perpendicular to the stripe. This is the same direction as the Burgers vector of the edge dislocation in metal. The successive charge hopping in the Burgers vector direction across the charge stripes may cause Cooper pairs as predicted by Zaanen et al (2004 Ann. Phys. 310 181). Indeed, this is supported by the experimental fact that the superconducting coherent length coincides with the inter-charge stripe distance in the wide carrier density range. The one-directional charge hopping perpendicular to the stripe causes the flat Fermi surface and the pseudogap near (π,0) and (0,π), but the states around (π/2,π/2) cannot be produced. The low-energy Raman scattering disclosed that the electronic states at the Fermi arc around (π/2,π/2) are coupled to the A1g soft phonon of the tetragonal-orthorhombic phase transition. This suggests that the Fermi arc is produced by the electron-phonon interaction. All the present Raman data suggest that Cooper pairs are formed at moving edge dislocations of dynamical charge stripes.

Correlation between Raman sum and optical conductivity sum in La(2-x)Sr(x)CuO4.

In a strongly correlated electron system, the single-particle spectral function changes into a coherent peak and incoherent humps which extend over 1 eV. The incoherent parts lose the symmetry and k dependence, so that the Raman spectra with different symmetries become identical and they are expressed by the optical conductivity. We found that the B1g and B2g spectra in La(2-x)Sr(x)CuO4 become identical above 2000 cm(-1) in the underdoped phase, if Fleury-Loudon type B1g two-magnon scattering is removed. The first Raman susceptibility moment correlates with the generalized optical conductivity moment. The good correlation arises from the incoherent states of a hump from 1000 to 4000 cm(-1). The hump is the only structure of the incoherent electronic states in the mid-infrared absorption spectra below 1.4 eV at low carrier densities. The energy is twice the separated dispersion segments of the spin wave in the k(perpendicular) stripe direction. The incoherent state is formed by the magnetic excitations created by the hole hopping in the antiferromagnetic spin stripes in the real space picture.

Changes in the weights of the accessory sex organs in male CD/IGS rats (Rattus norvegicus) after castration.

This study was designed to detect time-course changes in the weights of accessory sex organs after castration. Crj:CD(SD) IGS rats (Rattus norvegicus) were castrated at age of 6-weeks and sacrificed within 14 days of the procedure. The ventral prostate, vesicular gland, bulbospongiosus/levator ani muscle, glans penis and bulbourethral glands were then weighed. The ventral prostate and vesicular gland had significantly decreased in weight 8 and 6 days after castration, respectively. The other organs did not decrease in weight significantly between time periods though there was an overall decrease in weight.

Preputial separation and glans penis changes in normal growing Crj: CD (SD) IGS rats.

This study was designed to detect preputial separation and glans penis changes in normal growing SD rats. We examined the changes until 53 days after birth. The glans penis surface changed from a protruding os penis structure to a W shape, and from a W shape to a flattened surface with age. The protruding os penis structure changed gradually to the W shape from postnatal day (PND) 30, and all rats had the W shape by PND 35. The flattened surface was observed from PND 39, and all rats had this structure by PND 44. In all rats, the day of complete preputial separation exactly corresponded to the day of appearance of the flattened surface.

[The influence of the alcohol and the low protein diet on rat pancreas].

We investigated the influence of alcohol and the low protein diet upon rat pancreas. Rats were separated in four groups, 1) Control diet group (Cont), 2) Alcohol diet group (Al), 3) Low protein diet group (Lp), 4) Low protein and alcohol diet group (Lp+Al). They were fed on isocaloric liquid diet compulsorily through the gastric tube. They were sacrificed 3, 6, 12 weeks after. By the light microscopic observation on the rat pancreas which were fed for 12 weeks, lipid droplets in the acinar cells were observed in all groups other than Cont. Apoptosis was founded in Lp and Lp+Al groups. Protein plugs were observed in all groups, and no relation was found between the plugs and the location of the injured acinar cells. By the electromicroscopic observation, in Lp+Al group, acinar cells were typically injured (ER dilation, atrophic nuclei, mitochondria degeneration, etc.) and mesenchymal cells appeared among acinar cells. These results suggest that alcohol causes pancreatic acinar cell injury directly, and relative low protein diet helps to turn it worse.

Mycotoxin production by Chaetomium spp. and related fungi.

Screening for mycotoxin production by Chaetomium spp. and related fungi on rice culture was conducted by a combination of cytotoxicity tests using HeLa cells and thin-layer chromatography. Producers of sterigmatocystin, O-methylsterigmatocystin, chaetochromin, chaetocin, chetomin, cochliodinols, and mollicellin G were found and the taxonomic significance of these findings is discussed.

Ultrasonically guided percutaneous transhepatic bile drainage: a single-step procedure without cholangiography.

Percutaneous transhepatic bile drainage under real-time ultrasonic guidance was performed in 16 patients (21 procedures) without cholangiography. All bile ducts were successfully intubated. Merits of ultrasonically guided percutaneous transhepatic bile drainage are (a) the fact that only a single step is involved, without thin-needle cholangiography; (b) no contrast medium is injected; (c) the left-sided approach permits longer intubation; and (d) irradiation is not employed.

The production of chaetoglobosins, sterigmatocystin, O-methylsterigmatocystin, and chaetocin by Chaetomium spp. and related fungi.

Production of mycotoxins by Chaetomium spp. and related fungi on rice culture was examined by a combination of cytotoxicity tests using HeLa cells and thin-layer chromatography. Three species, C. mollipilium, C. rectum, and C. subaffine, as well as C. cochliodes and C. globosum, were proved to produce chaetoglobosins. From cultures of four strains of Chaetomium sp., assigned to C. thielavioideum, and one strain of Farrowia sp., chaetocin, sterigmatocystin, and O-methylsterigmatocystin were isolated. Morphological characteristics of the producers of sterigmatocystins are described.

Echo guided percutaneous transhepatic cholangiography with puncture transducer.

Conventional percutaneous transhepatic cholangiography (PTC) has some disadvantages because it is customarily performed blindly. If the bile duct is made visible, these disadvantages are eliminated. The biliary tree, if dilated, can be clearly delineated by ultrasound technique. By combining the B-mode examination of the biliary tract with the ultrasonic puncture transducer, percutaneous transhepatic cholangiography was performed successfully in 16 examinations on 12 patients. PTC needle could be inserted directly into the lumen of the bile duct without appreciable difficulty. The echo guided PTC was found to be an easier, safer, and more reliable method than the conventional blind technique.