Ferroelectric-like metallic state in electron doped BaTiO3

We report that a ferroelectric-like metallic state with reduced anisotropy of polarization is created by the doping of conduction electrons into BaTiO3, on the bases of x-ray/electron diffraction and infrared spectroscopic experiments. The crystal structure is heterogeneous in nanometer-scale, as enabled by the reduced polarization anisotropy. The enhanced infrared intensity of soft phonon along with the resistivity reduction suggests the presence of unusual electron-phonon coupling, which may be responsible for the emergent ferroelectric structure compatible with metallic state.

Displacement-type ferroelectricity with off-center magnetic ions in perovskite Sr(1-x)Ba(x)MnO3

We report a ferroelectric transition driven by the off-centering of magnetic Mn(4+) ions in antiferromagnetic Mott insulators Sr(1-x)Ba(x)MnO(3) with a perovskite structure. As x increases, the perovskite lattice shows the typical soft-mode dynamics, as revealed by the momentum-resolved inelastic x-ray scattering and far-infrared spectroscopy, and the ferroelectricity shows up for x ≥ 0.45. The observed polarization is comparable to that for a prototypical ferroelectric BaTiO(3). We further demonstrate that the magnetic order suppresses the ferroelectric lattice dilation by ∼70% and increases the soft-phonon energy by ∼50%, indicating the largest magnetoelectric effects yet attained.

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.

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.

Cycloidal spin order in the a-axis polarized ferroelectric phase of orthorhombic perovskite manganite

The ferroelectric state in an orthorhombic perovskite RMnO3 (R=Gd0.7Tb0.3) was proved by neutron scattering studies to show the cycloidal spin state with the ab-spiral plane and the spin-helicity dependent polarization vector along the a axis, sharing the microscopic origin (inverse Dzyaloshinskii-Moriya interaction) with the more widely observed P||c state (e.g., for R=Tb and Dy) with the bc-spiral plane. The magnetic-field induced polarization flop from P||c to P||a as well known for RMnO3 is thus assigned to the orthogonal flop of the spin spiral plane from bc to ab.

[Significance and effects of intraperitoneal cisplatin administration for ovarian cancer]

We studied the efficacy and safety of combination chemotherapy in which a high-dose platinum agent was administered intraperitoneally (i.p.) plus intravenously (i.v.) to 22 patients with stage III ovarian cancer. The chemotherapy consisted of etoposide (i.p.), cisplatin (i.p.), and carboplatin (i.v.). Each course was repeated every 4 weeks and a maximum of 5 courses was given in the 6 months following the initial surgery. As a control, 13 patients received different chemotherapy (CAP etc.) in which cisplatin, cyclophosphamide and doxorubicin pirarubicin hydrochloride were administered. The mean (SD) total dose of cisplatin in the patient group group (790.6 +/- 317.0 mg/m2) over the 6 months was significantly higher than in the control group (377.2 +/- 215.1 mg/m2). The overall response rate (CR + PR) 6 months after the completion (95.5%) was significantly higher in the study patients than in the control group (53.1%). The 1, 3, 5-year survival rates were significantly higher in the EPJ group (91.0, 59.0, 42.1%) than in the control group (53.8, 15.4, 15.4%). There was no significant difference in renal toxicity or bone marrow suppression (leukopenia and thrombocytopenia) between the two groups. EPJ therapy allowed an increased dose of cisplatin in the treatment of ovarian cancer without enhancing renal toxicity, resulting in higher response and survival rates. This study demonstrated that this therapy is an effective and well-tolerated regimen.

[A case report: complete remission of stage IV uterine cervix carcinoma by immuno-chemotherapy with intraarterial infusion using implantable reservoir system]

A patient with neck lymph node metastasis from squamous carcinoma of the uterine cervix was treated by immunotherapy and neo-adjuvant intraarterial infusion chemotherapy (OK-432 ic, etoposide 25 mg/body x 7 days po, CDDP 100 mg/m2/5 hr iA, CPM 200 mg/body iv, THP 50 mg/m2/2 hr iA). Three courses of the neo-adjuvant chemotherapy were given. After the first course, the neck metastatic tumor appeared remarkably small. After the second, the neck tumor disappeared and the uterine tumor appeared small and to have good movement. Hysterectomy was performed one month after. Each tissue platina concentration (microgram/cm3) is 9.12 uterus cervix, 10.9 uterus corporis, 8.17 fallopian tube, 14.0 ovarium, 1.47-0.88 pelvic lymph node. This patient was treated with irradiation after operation, and is presently in a state of cytological complete remission. Now she continues maintenance immunochemotherapy with UFT and OK-432 with a home doctor.

[Estimation of 3 rate constants of the 3 compartments model in PET measurement by a weighted integral method--simulation of estimation errors]

A simulation study to evaluate the errors in rate constants of the three compartment model using the weighted integral method was performed. Ten combinations of 7 kinds of weight functions, the errors were tested in 18F fluorodeoxyglucose (18FDG) study. The error factors arising in PET measurement were statistical noise, cerebral blood volume, time shift and scanning time of PET measurement. Errors in each rate constant were within the range of 10 percent and those in k1k3/(k2+k3) within 1 percent. The weighted integral method was confirmed to be a faster method than the conventional least squares method within a reasonable error range.

[A simulation study to evaluate the statistical noise and spatial resolution in image reconstruction of emission computed tomography--with respect to the optimization of the filter function in the convolution integral]

Filtered backprojection method has been commonly used to reconstruct images in the field of the computed tomography (CT). However, in the emission CT such as positron and single photon CT, poor counting static which are caused by limited dosage to patients, limited counting rate capacity and limited efficiency of the imaging device, produce a statistical noise in the reconstructed image. The magnitude of the statistical noise and the spatial resolution were evaluated for various shapes of the filter used in the convolution integrals of the filtered back-projection procedure. The statistical noise was proportional to the inverse of the root of the total number of counts for any filters. The high-frequency-cut characteristic of the filter reduced the statistical noise, but increased the spatial resolution in the images. It was possible to optimize the shape of the filter for given total number of counts and required statistical noise and spatial resolution.