Deformation of the moving magnetic skyrmion lattice in MnSi under electric current flow.

Topological defects are found ubiquitously in various kinds of matter, such as vortices in type-II superconductors, and magnetic skyrmions in chiral ferromagnets. While knowledge on the static behavior of magnetic skyrmions is accumulating steadily, their dynamics under forced flow is still a widely open issue. Here, we report the deformation of the moving magnetic skyrmion lattice in MnSi under electric current flow observed using small-angle neutron scattering. A spatially inhomogeneous rotation of the skyrmion lattice, with an inverse rotation sense for opposite sample edges, is observed for current densities greater than a threshold value j t ~ 1 MA m-2 (106 A m-2). Our result show that skyrmion lattices under current flow experience significant friction near the sample edges due to pinning, this being a critical effect that must be considered for anticipated skyrmion-based applications at the nanoscale.

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.

Collective bulk carrier delocalization driven by electrostatic surface charge accumulation.

In the classic transistor, the number of electric charge carriers--and thus the electrical conductivity--is precisely controlled by external voltage, providing electrical switching capability. This simple but powerful feature is essential for information processing technology, and also provides a platform for fundamental physics research. As the number of charges essentially determines the electronic phase of a condensed-matter system, transistor operation enables reversible and isothermal changes in the system's state, as successfully demonstrated in electric-field-induced ferromagnetism and superconductivity. However, this effect of the electric field is limited to a channel thickness of nanometres or less, owing to the presence of Thomas-Fermi screening. Here we show that this conventional picture does not apply to a class of materials characterized by inherent collective interactions between electrons and the crystal lattice. We prepared metal-insulator-semiconductor field-effect transistors based on vanadium dioxide--a strongly correlated material with a thermally driven, first-order metal-insulator transition well above room temperature--and found that electrostatic charging at a surface drives all the previously localized charge carriers in the bulk material into motion, leading to the emergence of a three-dimensional metallic ground state. This non-local switching of the electronic state is achieved by applying a voltage of only about one volt. In a voltage-sweep measurement, the first-order nature of the metal-insulator transition provides a non-volatile memory effect, which is operable at room temperature. Our results demonstrate a conceptually new field-effect device, extending the concept of electric-field control to macroscopic phase control.

Tissue rinse liquid-based cytology: a feasible tool for the intraoperative pathological evaluation of sentinel lymph nodes in breast cancer patients.

OBJECTIVES: A unique diagnostic method was designed for the intraoperative pathological evaluation of sentinel lymph nodes (SLNs) in breast cancer patients, and the results were verified with 2 years of experience. METHODS: Excised lymph nodes were cut into 2-mm-thick slices and rinsed thoroughly in CytoRich Red(®). The sliced tissues were embedded in a paraffin block. Three cytological glass slides of the cells exfoliated in CytoRich Red(®) were prepared by the SurePath(®) liquid-based cytology (LBC) technique. Two slides were stained by the Papanicolaou method, and the remaining slide was immunostained with an anti-keratin antibody. This process is called tissue rinse liquid-based cytology (TRLBC). The results of TRLBC were compared with those of the final pathological diagnoses, including immunostaining with an anti-keratin antibody on paraffin blocks (PB). RESULTS: This study analysed 444 SLNs from 247 consecutive breast cancer patients. It required 35 minutes to complete the intraoperative diagnosis on a single node, and it took an additional 5 minutes per node if more than one node was submitted. When the results of PB were assumed to be the gold standard, the sensitivity and specificity of TRLBC were 81.9% and 96.1%, respectively. TRLBC detected all nodes with macrometastasis and 23 of 24 nodes with micrometastasis. Fifteen false-negative TRLBC results were 'isolated tumour cell clusters' on PB, but there was one with micrometastasis histologically. Four of 14 false-positive TRLBC results were proven to be true positive by supplementary examination using step sectioning of the paraffin blocks of the nodes. CONCLUSION: TRLBC is a feasible and promising intraoperative cytopathological tool showing a comparable efficacy to PB while still allowing the conventional postoperative histological examination.

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.