428 research outputs found

    Magnetic properties of epitaxial Fe3_3O4_4 films with various crystal orientations and TMR effect in room temperature

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    Fe3_3O4_4 is a ferrimagnetic spinel ferrite that exhibits electric conductivity at room temperature (RT). Although the material has been predicted to be a half metal according to ab-initio calculations, magnetic tunnel junctions (MTJs) with Fe3_3O4_4 electrodes have demonstrated a small tunnel magnetoresistance effect. Not even the sign of the TMR ratio has been experimentally established. Here, we report on the magnetic properties of epitaxial Fe3_3O4_4 films with various crystal orientations. The films exhibited apparent crystal orientation dependence on hysteresis curves. In particular, Fe3_3O4_4(110) films exhibited in-plane uniaxial magnetic anisotropy. With respect to the squareness of hysteresis, Fe3_3O4_4 (111) demonstrated the largest squareness. Furthermore, we fabricated MTJs with Fe3_3O4_4(110) electrodes, and obtained an TMR effect of -12\% at RT. The negative TMR ratio corresponded to the negative spin polarization of Fe3_3O4_4 predicted from band calculations

    Phase Equilibrium Relations of Semiclathrate Hydrates Based on Tetra- n-butylphosphonium Formate, Acetate, and Lactate

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    Phase equilibrium (temperature-composition) relations of tetra-n-butylphosphonium formate (TBP-For), acetate (TBP-Ace), and lactate (TBP-Lac) semiclathrate hydrate systems have been measured. The highest equilibrium temperatures of TBP-For, TBP-Ace, and TBP-Lac semiclathrate hydrates were 280.9, 284.6, and 283.8 K at the atmospheric pressure, respectively, where the composition of tetra-n-butylphosphonium carboxylate was approximately 0.035 ± 0.001 (mole fraction) in every system. The dissociation enthalpies of tetra-n-butylphosphonium carboxylate semiclathrate hydrates were measured by differential scanning calorimetry. The dissociation enthalpies of TBP-For, TBP-Ace, and TBP-Lac semiclathrate hydrates were (187 ± 3), (193 ± 3), and (177 ± 3) J·g-1, respectively.Jin Shimada, Masami Shimada, Takeshi Sugahara, et al. Phase Equilibrium Relations of Semiclathrate Hydrates Based on Tetra-n-butylphosphonium Formate, Acetate, and Lactate. Journal of Chemical & Engineering Data, 63 (9), 3615-3620, September 13, © 2018 American Chemical Society. https://doi.org/10.1021/acs.jced.8b0048

    Chirality-selected crystal growth and spin polarization over centimeters of transition metal disilicide crystals

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    We performed a chirality-controlled crystal growth of transition metal disilicide NbSi2_{2} and TaSi2_{2} by using a laser-diode-heated floating zone (LDFZ) method. The crystal chirality was evaluated in the crystals of centimeters in length by performing single crystal X-ray diffraction as well as probing a spin polarization originating from chirality-induced spin selectivity (CISS) effect. The crystals of right-handed NbSi2_{2} and of left-handed TaSi2_{2} were obtained in the conventional LDFZ crystal growth, while the left-handed NbSi2_{2} and right-handed TaSi2_{2} crystals were grown by the LDFZ method with the composition-gradient feed rods. The spin polarization via the CISS was observed over centimeters in the NbSi2_{2} single crystals and the sign of the CISS signals was dependent on the chirality of crystals. The correlation between the crystal chirality and CISS signals indicates that the CISS measurements work as a non-destructive method for chirality determination even in centimeter-long specimens.Comment: 9 pages, 6 figure

    Culture System for Bobwhite Quail Embryos from the Blastoderm Stage to Hatching

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    Quail are divided phylogenetically into two groups, Old World quail and New World quail. Old World quail, such as the Japanese quail (Coturnix japonica), belong to the Phasianidae and distributed in the Palaearctic region (Europe, North Africa, and Asia), whereas New World quail, such as the bobwhite quail (Colinus virginianus), belong to the Odontophoridae and are restricted to North and South America. Both the bobwhite quail and the Japanese quail are used as models for avian safety assessment as recommended by the Organisation for Economic Co-operation and Development (OECD) guidelines. However, biological studies on the bobwhite quail have been limited compared with those on the Japanese quail. We have therefore now developed an ex vivo culture protocol for bobwhite quail embryos from the blastoderm stage through hatching. Of the various culture conditions examined in the present study, a good hatching rate (39%) was obtained when the embryos were cultured ex vivo in a two-step procedure. Unincubated embryos (with egg yolk) were first cultured inside the shell of a Japanese quail egg (11.5 to 13.0 g whole egg weight) together with chicken thin albumen for 63 to 65 h and were then transferred to the shell of a small-sized chicken egg (38 g whole egg weight) until hatching. This ex vivo culture system should provide to be widely applicable to the maintenance and generation of manipulated birds for basic and applied studies on the bobwhite quail.ArticleJOURNAL OF POULTRY SCIENCE. 50(2):155-158 (2013)journal articl

    Thermodynamic Properties of Tetra-n-butylphosphonium Dicarboxylate Semiclathrate Hydrates

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    Semiclathrate hydrate (SCH) is one of the phase change materials suitable for cold energy storage. Thermodynamic properties of SCHs, such as an equilibrium temperature and the dissociation enthalpy, depend on the size and shape of the guest substances. In the present study, to reveal the effects of steric conformations of the guest anions on the thermodynamic properties of SCHs, tetra-n-butylphosphonium dicarboxylate (TBP-DC) SCHs, where the anion was oxalate (TBP-Oxa), malonate (TBP-Mal), succinate (TBP-Suc), glutarate (TBP-Glu), maleate (TBP-Male), or fumarate (TBP-Fum), were investigated. TBP-Oxa, -Mal, -Suc, and -Fum SCHs had similar equilibrium temperatures, whereas the equilibrium temperatures of TBP-Glu and -Male SCHs were higher. This suggests that the size and conformation of glutarate and maleate anions are appropriate for the cage structures of SCHs. Moreover, we compared the equilibrium temperatures of TBP-Suc, -Male, and -Fum SCHs because TBP-Suc, -Male, and -Fum have similar anion structures. The equilibrium temperature of TBP-Suc SCH was similar to that of TBP-Fum SCH, whereas TBP-Male SCH showed a higher equilibrium temperature. This result implies that the succinate anion is accommodated in the trans conformation, similar to the fumarate anion, in the hydrate cages.Jin Shimada, Moe Yamada, Atsushi Tani et al. Thermodynamic Properties of Tetra-n-butylphosphonium Dicarboxylate Semiclathrate Hydrates. Journal of Chemical & Engineering Data, 67 (1), 67-73, January 13, © 2022 American Chemical Society. https://doi.org/10.1021/acs.jced.1c0074

    Guideline-based Treatment of Glucocorticoid-induced Osteoporosis in Patients with Rheumatoid Arthritis: A Retrospective Study with the AORA Registry

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    Glucocorticoid-induced osteoporosis (GIOP) is one of the side effects associated with glucocorticoid (GC) therapy. In 2014, the Japanese Society for Bone and Mineral Research (JSBMR) provided new guidelines for the management and treatment of GIOP. The aim of the present study was to clarify the prevalence of patients with rheumatoid arthritis (RA) requiring treatment according to the new guidelines and to identify risk factors associated with lack of treatment in these patients. Patients in the 2018 Akita Orthopedic group on Rheumatoid Arthritis (AORA) database were enrolled. Of 2,234 patients with RA in the database, 683 (30.6%) met the 2014 JSBMR guideline treatment criteria, and 480 (70.3%) had been treated. The untreated group included a larger number of males, younger patients, and patients treated in clinics rather than hospital (p<0.001, p=0.015, and p<0.001, respectively). Multivariate analyses found that male sex, younger age, and clinic-based RA care were significant risk factors associated with lack of treatment (p<0.001, p=0.013, and p<0.001, respectively). Thus, male sex, younger age, and clinic-based care were identified as risk factor

    Fibrinogen–platelet ratio and pancreatic cancer

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    Background : Several prognostic factors were reported in pancreatic cancer. The fibrinogen–platelet ratio (FPR) was reported as a prognostic factor of resectable gastric cancer. In this report, the FPR was evaluated in patients with resectable pancreatic cancer. Methods : Between 2004 and 2019, 163 patients with curative resection for pancreatic cancer were enrolled. Cases of non-curative resection were excluded. The FPR was calculated using the preoperative plasma fibrinogen and the platelet counts and the cut-off value was determined by receiver operating characteristic (ROC) curve analysis. The patients were divided into high and low FPR groups according to this cut-off value. Results : The cut-off value of FPR was 25.2. Among age, sex, body mass index (BMI), and surgical factors including surgery type, volume of blood loss and surgery time, there was no significant difference between the two groups. Patients in the low FPR group had significantly better overall survival (OS) and relapse-free survival (RFS) compared with the high FPR group (P 300 U / ml, and receipt of adjuvant chemotherapy were independent risk factors for OS and DFS. Conclusions : The FPR might be a prognostic factor for patients with resectable pancreatic cancer
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