Search Results - (Author, Cooperation:T. Terashima)

2018-01-09

American Physical Society (APS)

1098-0121

1095-3795

Physics

Superfluidity and superconductivity

2018-05-05

American Physical Society (APS)

0031-9007

1079-7114

Physics

Condensed Matter: Electronic Properties, etc.

2018-06-23

American Physical Society (APS)

0031-9007

1079-7114

Physics

Condensed Matter: Electronic Properties, etc.

2012-06-23

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

2011-04-09

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

2018-10-30

American Physical Society (APS)

1098-0121

1095-3795

Physics

Electronic structure and strongly correlated systems

2012-06-23

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

1089-7550

AIP Digital Archive

Physics

Epitaxial growth of BaTiO3 and SrTiO3 films by the reactive evaporation method was investigated using reflection high-energy electron diffraction (RHEED). The investigations were carried out using two growth methods: coevaporation and alternate evaporation of the metal elements in an oxygen atmosphere. Atomic layer growth was achieved by the alternate supply of Ba or Sr and Ti on the growing surface. In the case of coevaporation, epitaxial growth occurred in a two-dimensional unit-cell-by-unit-cell mode. The surface of each unit cell is terminated by a (TiO2) layer. Artificial superlattices of BaTiO3/SrTiO3 were fabricated by monitoring the film thickness with the RHEED oscillations.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

Ultrathin YBa2Cu3O7−δ epitaxial films were successfully grown in situ on (001) SrTiO3 and MgO substrates by means of ozone-incorporating activated reactive evaporation. The x-ray-diffraction study was carefully examined to determine the structural properties of the grown films. Excellent crystallinity with no interfacial disorders was revealed by the appearance of the Laue oscillations. It was found that in a well lattice-matched YBa2Cu3O7−δ/SrTiO3 system, the crystallinity was deteriorated due to defect introduction at the critical layer thickness hc ( ∼ 130 A(ring)). Interestingly, also in a poorly lattice-matched YBa2Cu3O7−δ/MgO system, excellent crystallinity was revealed even at above hc ( 〈 24 A(ring)). This implies that an anomalous misfit relaxation process exists in the YBa2Cu3O7−δ/MgO system. In such a system, no crystal imperfection of the MgO substrate caused by defect introduction was elucidated by the grazing incidence x-ray scattering, which indicated that the MgO substrate did not contribute to the anomalous misfit relaxation. The anomalous growth manner was also found in YBa2Cu3O7−δ/MgO according to surface morphology investigations. Below 40 A(ring)( (approximately-greater-than) hc), island nucleation growth was found. Above 40 A(ring), it was observed that an atomically smooth surface was obtained and the crystallinity was simultaneously improved. It is suggested that YBa2Cu3O7−δ possesses an anomalous misfit relaxation mechanism, and that especially in the growth on MgO, it couples with the characteristic growth behavior at the initial stage.

Electronic Resource

1365-2133

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource

1089-7550

AIP Digital Archive

Physics

Electronic Resource

1089-7550

AIP Digital Archive

Physics

Thin films of BaTiO3 have been epitaxially grown on Pt(001)/MgO(100) substrates by reactive evaporation. Structural and electrical properties were investigated as a function of film thickness. In situ reflection high-energy electron diffraction and cross-sectional transmission electron microscope observations have revealed that the BaTiO3 films are epitaxially grown on Pt/MgO substrates from the initial stage without any other phase formation. From the images of an atomic force microscope, it has been found that islands of BaTiO3 are present on the bare Pt surface at the initial stage of deposition; the island structure changes to a continuous layer above 1.2 nm in thickness and BaTiO3 grows in a two-dimensional mode. The lattice parameters and the dielectric properties are dependent on the film thickness. Thermodynamic theory was introduced to explain the thickness dependence of the relative dielectric constant εr. Good agreement between the experimental results and the theoretical calculations leads to the conclusion that the thickness dependencies of the lattice parameters and the dielectric constants are caused by the two-dimensional stress due to the lattice mismatch between Pt and BaTiO3 and/or the difference in the thermal expansion coefficients of BaTiO3 and the MgO substrate. © 1994 American Institute of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Superconducting Nd-Ce-Cu-O thin films were epitaxially grown on SrTiO3 (100) by activated reactive evaporation. As-grown films showed the metallic temperature dependence of the resistivity and superconducting transition at 12.5 K (R=0). The remarkable parallel shift of the onset temperature of the resistive transition in the magnetic fields was observed. Ginzburg–Landau coherence lengths along the c axis and in the basal plane are 7 and 96 A(ring), respectively.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Ferroelectric BaTiO3 thin films were directly and epitaxially grown on SrTiO3 single crystal and epitaxial Pt film substrates by activated reactive evaporation. The substrate temperature was around 600 °C. For (100) oriented as-grown films, a typical ferroelectric hysteresis loop and a maximum of dielectric constant at about 115 °C were observed. The resistivity was as high as 109 Ω cm and the breakdown voltage was 2.7 MV/cm for as-grown BaTiO3 films.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

We have, for the first time, made quasi-particle tunneling measurements on a YBa2Cu3O7−x(001)/Y2O3 (001)/YBa2 Cu3 O7−x (001)junction, which was epitaxially grown on a MgO(100) substrate in an in-situ process. Both layers of YBa2 Cu3 O7−x showed the same superconducting transition of Tc end =86 K with ΔT(R=10–90%)=1.5 K. Quasi-particle tunneling in the direction perpendicular to the Cu-O planes was measured. A gap parameter Δ(4.5 K) of 9.0±0.2 meV and a value of 2Δ/kTc of 3.5+0.4−0.6 were obtained.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Normal-metal/insulator/superconductor (NIS) junctions were fabricated using thin films of YBa2Cu3O7−x (YBCO) or ErBa2Cu3O7−x. These were epitaxially grown on single-crystal SrTiO3 by the activated reactive evaporation method. For some NIS junctions prepared on SrTiO3 (110) substrates, we observed multipeaks in the differential conductance versus voltage curve. NIS junctions using single-crystal YBCO films on SrTiO3 (100) showed a set of peaks, from which we obtained a gap parameter of 11.5±1.5 meV at 4.4 K and a coupling constant of 3.2±0.4.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Neutron diffraction measurements were made on artificial superlattices of CoO-NiO, (CoO)m(NiO)n×l prepared on the (0001) surface of α-Al2O3. (111) layers of CoO and NiO, each less than 2 nm thick (2≤m,n≤8), were stacked alternatively to a total thickness of less than 70 nm (m+n≤15,l≤25). A well-defined magnetic Bragg peak indexed as (1/2 1/2 1/2) was observed for all the samples, and a magnetic structure of type FCC2 with the spin axis lying in the (111) planes grown was suggested. The temperature dependence of the magnetic peak intensity revealed a sharp, single magnetic transition. The Néel temperature was found to vary as a linear function of n/(m+n).

Electronic Resource

1077-3118

AIP Digital Archive

Physics

The orientation of YBa2Cu3O7−x thin films grown on (110) planes of SrTiO3 by activated reactive evaporation was investigated by means of reflection high-energy electron diffraction. The orientation of the films depended on the substrate temperature. The films with (110) planes parallel to the substrate surface grew in a narrow range of substrate temperatures around 530 °C, while the films with (103) planes parallel to the surface grew at temperatures above 600 °C. The change of the epitaxial orientation with the substrate temperature is discussed in terms of the temperature dependence of the lattice mismatch between YBa2Cu3O7−x and SrTiO3.

Electronic Resource

1365-2133

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Summary  Background The incidence of atopic dermatitis (AD) has increased in Japan, along with the number of patients with severe and treatment-resistant AD in urban and industrial areas. We hypothesize that these changes could be due to increased reactive oxygen species (ROS) generated from environmental pollution and solar radiation. Objectives To demonstrate whether direct oxidative protein damage of the stratum corneum of the biopsied skin from AD patients is increased when compared with controls. Patients and methods Carbonyl moieties in skin biopsies from 75 patients with AD were assessed using both spectrophotometric and immunohistochemical detection of the formation of dinitrophenylhydrazone (DNP) from dinitrophenylhydrazine (DNPH). These were compared with diseased and normal controls. Lipid peroxidation was also assessed by staining with antibody to 4-hydroxy-2-nonenal (4-HNE), an aldehyde product of oxidized ω-6-fatty acids. In addition, the activity of superoxide dismutase (SOD), an effective scavenger of ROS, was assessed and compared with controls. Results The level of protein carbonyl moieties in patients' skin was elevated and correlated directly with the severity of the disease. In contrast, DNP formation was not significantly increased in diseased controls, when compared with healthy volunteers, and no statistical significance was found between the two control groups. SOD activity was increased except for those with extra-severe disease. Positive staining with anti-DNP antibody and anti-4-HNE antibody were found in the most superficial layers of the stratum corneum. Conclusions This study has found an association between AD severity and markers of ROS-associated damage, adding weight to the hypothesis that environmentally generated ROS may induce oxidative protein damage in the stratum corneum, leading to the disruption of barrier function and exacerbation of AD.

Electronic Resource

1365-2133

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Background  Tacrolimus, produced by the fungus Streptomyces tsukabaensis, is a potent macrolide immunosuppressant widely used in liver and kidney transplantation. Topical tacrolimus has recently been found to be an effective treatment for atopic dermatitis (AD).Objectives  Because of the well-known association between T-cell immunosuppression and an increased risk of carcinogenesis, we investigated the effect of topical tacrolimus on skin carcinogenesis in 117 mice.Methods  Approximately 8 cm2 of the shaved dorsal skin of 7-week-old female CD-1 mice was treated with 7,12-dimethylbenz[α]anthracene (DMBA) dissolved in acetone, which is in general use as a tumour initiator, or acetone alone, on day 1 of the experiment, followed by promoting treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA) with or without tacrolimus, or acetone with or without tacrolimus, for 20 weeks. The mice were divided into six treatment groups: (1) DMBA followed by acetone; (2) DMBA followed by TPA; (3) DMBA followed by acetone + tacrolimus; (4) DMBA followed by TPA + tacrolimus; (5) acetone followed by acetone + tacrolimus; and (6) acetone followed by acetone (control).Results  The induction of skin tumours was significantly greater in the TPA-treated groups than in the absence of TPA. However, after 14 weeks there was marked synergy between tacrolimus and the DMBA/TPA regimen, with 0·47 ± 0·13 (mean ± SD) new tumours per mouse per week in group 4 vs. 0·10 ± 0·025 in group 2 (P 〈 0·01), and 0·01 ± 0·002 in group 3. A significant reduction in the CD4/CD8 ratio was found in axillary and inguinal lymph nodes in tacrolimus-treated mice, supporting the presumption that the immunosuppressive effect of the drug was responsible for its effect in promoting tumorigenesis. The major increase in tumours caused by topical tacrolimus was of papillomas, not squamous cell carcinomas. Papillomas are uncommon in humans, and are benign. However, 8·5% of the tumours found in the experiment were squamous cell carcinomas, and a considerable synergy between topical tacrolimus and conventional carcinogens was observed, raising the spectre of some risk of skin carcinogenesis in AD patients undergoing prolonged treatment with tacrolimus.Conclusions  Caution and careful surveillance are required with regard to skin lesions in patients treated with tacrolimus for prolonged periods.

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