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We performed the electrical resistivity and thermoelectric power measurements of the polycrystalline La0.8Ti0.2OBi(S1-xSex)2. The electrical resistivity of La0.8Ti0.2OBi(S0.7Se0.3)2 at room temperature dramatically decreases, and the temperature dependence shows metallic-like behavior. From the electrical resistivity, superconductivity was not observed in La0.8Ti0.2OBi(S1-xSex)2 above 2.8 K. The value of thermoelectric power S(300 K) of La0.8Ti0.2OBiSSe was about -65 μV/K, which is comparable to that of the polycrystalline LaOBiS2. The value of S(300 K) of La0.8Ti0.2OBiS2 was about -115 μV/K. These power factors are relatively smaller than that of the polycrystalline LaOBiSSe.

Electrical resistivity of LaO0.5F0.5Bi(S0.9Se0.1)2 have been measured at a temperature range of 2.8 ∼ 300 K by applying several hydrostatic pressures. Pressure-induced superconducting phase was observed above a pressure P of 0.85 GPa and Tc increased from 2.86 K to 8.42 K. The sudden increase of Tc in LaO0.5F0.5Bi(S0.9Se0.1)2 results from the structural phase transition from tetragonal (P4/nmm) to monoclinic (P21/m). Structural phase transition pressure Pc of LaO0.5F0.5Bi(S0.9Se0.1)2 is higher than that of LaO0.5F0.5BiS2. The increase of Pc is ascribed to the suppression of the displacement parameter of the in-plane chalcogen site induced by chemical pressure of Se-substitution.

Superconductivity is achieved in Nd1−xCexOBiS2 via electron doping using mixed-valence Ce ions. Single crystals with x = 0.2, 0.3, 0.4, and 0.5 are generated using a CsCl flux method. Plate-like single crystals with dimensions of 0.8 × 0.8 × 0.2mm³ were obtained. The magnetic susceptibility χ(T) indicates large diamagnetism, and the electrical resistivity ρ(T) indicates zero resistivity. The maximum value of Tc is observed at 4.7K in Nd0.8Ce0.2OBiS2 from χ(T). From the ρ(T) measurements taken in several magnetic fields, the upper critical field μ0Hc2(0) is estimated to be ∼12 and ∼0.34 T for the ab- and c-planes, respectively. We redetermined μ0Hc2(0) of NdO0.7F0.3BiS2, as ∼35 and ∼0.78 T for the ab- and c-planes, respectively. The anisotropic parameter Γ is estimated to be ∼35 for Nd0.7Ce0.3OBiS2 and ∼45 for NdO0.7F0.3BiS2. The μ0Hc2(0) of Nd0.7Ce0.3OBiS2 is approximately two times smaller than that of NdO0.7F0.3BiS2, although the difference of Γ is approximately 10. [ABSTRACT FROM AUTHOR]

We report the temperature dependence of tunneling conductance from 5 to 190K for overdoped TlBa2Ca2Cu3O8.5+δ (Tl1223) with TC ~ 112 K. The tunneling conductances exhibit clear dips at a voltage, Vdip, below TC, suggesting that the dip is of superconducting origin. Moreover, we have found that the mode energy Ω is 38 meV and independent of temperature, where Ω is defined as the difference between eVdip and the superconducting gap Δ. In addition, the temperature dependence of the tunneling dip strength is similar to that of the magnetic resonance intensity at (π, π) observed in inelastic neutron scattering experiments. We found that the relationship between the average mode energy ... and Δ for Tl1223 is a common feature of Bi2Sr2CaCu2O8+δ, where .../Δ increases with decreasing Δ, but does not exceed 2. These characteristic features of the tunneling dips are consistent with not only those of resonance spin excitation but also pairing models in which the (π, π) resonance is a collective spin excitation. [ABSTRACT FROM AUTHOR]

AbstractObjectives:The authors conducted a randomized controlled trial to clarify the efficacy and safety of alendronate plus alfacalcidol versus alendronate alone in a clinical setting.Research design and methods:Eligible patients were postmenopausal women with severe osteoporosis who were aged 70 years or older and had several risk factors for incident fractures. The primary endpoint was prevention of incident fractures, and the anti-fracture efficacy was evaluated in relation to the baseline serum 25(OH)D level.Results:A total of 2164 patients were randomized to alendronate plus alfacalcidol (combination therapy) or alendronate alone (monotherapy). Although the overall difference in the incidence of vertebral fracture between the two groups was not significant, the combination therapy group had a significantly reduced risk of vertebral fractures after the first 6 months (HR, 0.53). In subgroup analyses, the combination therapy group was superior in the strata of number of prevalent vertebral fractures of ≥2 (HR, 0.51) and grade 3 of prevalent vertebral fractures (HR, 0.55). The rate of non-vertebral weight-bearing bone fractures was significantly lower in the combination therapy group than in the monotherapy group during the follow-up period (HR, 0.31). A lower baseline 25(OH)D level was associated with a higher incidence of non-vertebral weight-bearing bone fractures (HR, 3.42) despite alendronate use. Although one patient given the combination therapy had mild hypercalcemia, serious hypercalcemia and unknown adverse events were not encountered. Because of the limitations presented in this study, these results may not apply to female patients with longer than 2 years of treatments, and to male osteoporosis patients.Conclusions:The combination therapy was no more effective for overall vertebral fracture prevention. However, subgroup analysis has shown that it was more effective for fracture prevention in patients with severe vertebral deformity, multiple prevalent vertebral fractures, and for non-vertebral weight-bearing bone fracture prevention. [ABSTRACT FROM AUTHOR]