426 research outputs found

    Monte Carlo Study of Relaxor Systems: A Minimum Model for Pb(In1/2_{1/2}Nb1/2_{1/2})O3_3}

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    We examine a simple model for Pb(In1/2_{1/2}Nb1/2_{1/2})O3_3 (PIN), which includes both long-range dipole-dipole interaction and random local anisotropy. A improved algorithm optimized for long-range interaction has been applied for efficient large-scale Monte Carlo simulation. We demonstrate that the phase diagram of PIN is qualitatively reproduced by this minimum model. Some properties characteristic of relaxors such as nano-scale domain formation, slow dynamics and dispersive dielectric responses are also examined.Comment: 5 pages, 4 figure

    Dual structures in PZN-xPT ferroelectric relaxors

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    We performed x-ray diffraction studies on a series of (1-xx)Pb(Zn1/3_{1/3}Nb2/3_{2/3})O3_3-xxPbTiO3_3 (PZN-xxPT) single crystals with different incident photon energies, and therefore different penetration depths. Our results show that outer-layers of ∌10\sim 10 to 50 ÎŒ\mum thick are present in all samples. The structure of those outer-layers is different from that of the inside of the crystals, by having much greater (rhombohedral) distortions. With increasing xx, rhombohedral-type lattice distortions develop, both in the outer-layer and the inside.Comment: submitted to Appl. Phys. Let

    Serum Levels of Testosterone in Patients with Poly-cythemia Vera

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    Abstract Despite its association with vascular events such as myocardial and cerebral infarction, polycythemia vera (PV) is characterized by low serum total cholesterol levels. Because several sex hormones are derived from cholesterol, statins may induce hypogodanism in male patients. Therefore, we assessed the relationship between serum total cholesterol and sex hormone levels according to gender. Medical records of 41 patients with erythrocytosis (hemoglobin concentrations: men >18.5 g/dL; women >16.5 g/dL) collected between August 2005 and December 2014 were reviewed for patient age, and gender, as well as clinical hematology, biochemistry, and endocrinology laboratory findings. Serum levels of testosterone were lower in men with PV than in patients with reactive erythrocytosis (RE) (PV: 385 ± 78 ng/mL versus RE: 529 ± 46 ng/mL). However, serum levels of testosterone in women with PV were comparable to those in patients in the nonerythrocytic group (PV: 20.5 ± 3.5 ng/mL versus non-erythrocytic group: 21.0 ± 4.3 ng/mL). Serum levels of testosterone were not related to serum levels of cholesterol. Therefore, we speculated that lower testosterone levels were not due to lower serum levels of cholesterol, a known adverse effect of statin. In conclusion, we report for the first time that serum levels of testosterone were lower in male PV patients than in those with RE; however, serum levels of testosterone in female patients with PV were not lower

    Resonant inelastic x-ray scattering study of hole-doped manganites La1-xSrxMnO3 (x=0.2 and 0.4)

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    Electronic excitations near the Fermi energy in the hole doped manganese oxides (La1-xSrxMnO3, x=0.2 and 0.4) have been elucidated by using the resonant inelastic x-ray scattering (RIXS) method. A doping effect in the strongly correlated electron systems has been observed for the first time. The scattering spectra show that a salient peak appears in low energies indicating the persistence of the Mott gap. At the same time, the energy gap is partly filled by doping holes and the energy of the spectral weight shifts toward lower energies. The excitation spectra show little change in the momentum space as is in undoped LaMnO3, but the scattering intensities in the low energy excitations of x=0.2 are anisotropic as well as temperature dependent, which indicates a reminiscence of the orbital nature

    N‐Substituted Nipecotic Acids as (S )‐SNAP‐5114 Analogues with Modified Lipophilic Domains

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    Potential mGAT4 inhibitors derived from the lead substance (S )‐SNAP‐5114 have been synthesized and characterized for their inhibitory potency. Variations from the parent compound included the substitution of one of its aromatic 4‐methoxy and 4‐methoxyphenyl groups, respectively, with a more polar moiety, including a carboxylic acid, alcohol, nitrile, carboxamide, sulfonamide, aldehyde or ketone function, or amino acid partial structures. Furthermore, it was investigated how the substitution of more than one of the aromatic 4‐methoxy groups affects the potency and selectivity of the resulting compounds. Among the synthesized test substances (S )‐1‐{2‐[(4‐formylphenyl)bis(4‐methoxyphenyl)‐methoxy]ethyl}piperidine‐3‐carboxylic acid, that features a carbaldehyde function in place of one of the aromatic 4‐methoxy moieties of (S )‐SNAP‐5114, was found to have a pIC50 value of 5.89±0.07, hence constituting a slightly more potent mGAT4 inhibitor than the parent substance while showing comparable subtype selectivity

    An epidemiological study on anemia among institutionalized people with intellectual and/or motor disability with special reference to its frequency, severity and predictors

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    BACKGROUND: To examine the type, frequency, severity, and predictors of anemia and its relationship with co-morbid conditions among institutionalized people with intellectual and/or motor disability. METHODS: We conducted a cross-sectional study at a public facility for people with intellectual and/or motor disability in Ibaraki prefecture, Japan. Health checkup data obtained in 2001 from 477 people with intellectual disability (male: 286, average age 40.6 ± 12.3; female: 191, average age 45.1 ± 11.6) were retrospectively reviewed. RESULTS: The prevalence of anemia among male participants was higher than in female participants for each disability category (intellectual disability, 41.1%, 4.2%; cerebral palsy, 37.5%, 4.8%; Down's syndrome, 15.0%, 0%; severe motor and intellectual disabilities, 61.9%, 16.7%). Most participants with anemia (93.8 – 100%) showed a normocytic normochromic anemia pattern. Multivariate analysis revealed that factors related to an increase in frequency included sex (male), low body mass index (BMI), use of anticonvulsants or major tranquilizers, and a high zinc sulfate turbidity test (ZTT) value. No clinically diagnosed co-morbid condition was found to be related to the presence of anemia. CONCLUSION: A high frequency of mild normocytic normochromic anemia in institutionalized people with intellectual and/or motor disability was observed, particularly among males. Medications and chronic inflammation may increase the risk of anemia

    Orthorhombic versus monoclinic symmetry of the charge-ordered state of NaV2O5

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    High-resolution X-ray diffraction data show that the low-temperature superstructure of alpha-NaV2O5 has an F-centered orthorhombic 2a x 2b x 4c superlattice. A structure model is proposed, that is characterized by layers with zigzag charge order on all ladders and stacking disorder, such that the averaged structure has space group Fmm2. This model is in accordance with both X-ray scattering and NMR data. Variations in the stacking order and disorder offer an explanation for the recently observed devils staircase of the superlattice period along c.Comment: REVTEX, 4 pages including 2 figures, shortened, submitted to PR

    X-ray anomalous scattering investigations on the charge order in αâ€Č\alpha^\prime-NaV2_2O5_5

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    Anomalous x-ray diffraction studies show that the charge ordering in αâ€Č\alpha^\prime-NaV2_2O5_5 is of zig-zag type in all vanadium ladders. We have found that there are two models of the stacking of layers along \emph{c-}direction, each of them consisting of 2 degenerated patterns, and that the experimental data is well reproduced if the 2 patterns appears simultaneously. We believe that the low temperature structure contains stacking faults separating regions corresponding to the four possible patterns.Comment: Submitted to Phys. Rev. Lett., 4 pages, 4 eps figures inserted in the tex

    Low-Temperature Structure of the Quarter-Filled Ladder Compound alpha'-NaV2O5

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    The low-temperature (LT) superstructure of αâ€Č\alpha'-NaV2_2O5_5 was determined by synchrotron radiation x-ray diffraction. Below the phase transition temperature associated with atomic displacement and charge ordering at 34K, we observed the Bragg peak splittings, which evidence that the LT structure is monoclinic. It was determined that the LT structure is (a−b)×2b×4c(a-b)\times 2b \times 4c with the space group A112A112 where a,ba, b and cc represent the high temperature orthorhombic unit cell. The valence estimation of V ions according to the bond valence sum method shows that the V sites are clearly separated into two groups of V4+^{4+} and V5+^{5+} with a zigzagzigzag charge ordering pattern. This LT structure is consistent with resonant x-ray and NMR measurements, and strikingly contrasts to the LT structure previously reported, which includes V4.5+^{4.5+} sites.Comment: 4 pages, 3 figures, 1 tabl
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