222 research outputs found

    Structures and Magnetic Properties of Tm1-yYyMn1-xCoxO3

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    The structure and magnetic properties of Tm1−y Y y Mn1−x Co x O3 with 0 ≦ x ≦ 0.5 and 0 ≦ y ≦ 0.3 were investigated by X-ray diffraction, specific heat and magnetization measurements. Thulium manganite TmMnO3 prepared by solid-state synthesis at ambient pressure is hexagonal and antiferromagnetic with a Nèel temperature T N of 86 K. The substitution of Y for Tm in TmMnO3 does not greatly affect the fundamental hexagonal structure. The magnetization and specific heat measurement results for Tm1−y Y y MnO3 can be qualitatively explained in terms of the dilution effect of Tm by Y. On the other hand, the structure of TmMn1−x Co x O3 changes gradually from hexagonal to orthorhombic with the substitution of Co for Mn; hexagonal and orthorhombic phases coexist in samples for x ≦ 0.3 whereas TmMn0.6Co0.4O3 is almost a single orthorhombic phase. The magnetization of TmMn0.6Co0.4O3 in a field of 250 Oe increases rapidly at about 60K with decreasing temperature. The difference between zero-field-cooled (ZFC) and field-cooled (FC) magnetizations increases remarkably at about 60 K. Moreover, the temperature dependences of the ZFC and the FC magnetizations exhibit peaks at about 40 and 30K, respectively. Thus, TmMn1−x Co x O3 exhibits complex magnetic properties

    Severe macular edema induced by pioglitazone in a patient with diabetic retinopathy: a case study

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    We report a case of severe diabetic macular edema (DME) that developed after pioglitazone was used by a patient with proliferative diabetic retinopathy. A 30-year-old woman with poorly controlled type 2 diabetes mellitus visited our clinic in 2004. She had moderate pre-proliferative diabetic retinopathy OU. Because of the rapid progression of the diabetic retinopathy, she received pan-retinal photocoagulation in both eyes. Two weeks before using pioglitazone, her visual acuity was 0.9 OD and 0.7 OS. On October 2007, pioglitazone was prescribed by her internist because of poorly controlled blood glucose level. Two weeks later, her body weight increased, and her face became edematous. Her visual acuity decreased to 0.5 OU, and ophthlamoscopy showed severe DME in both eyes. Two weeks after stopping pioglitazone, her visual acuity improved to 0.8 OD and 0.5 OS, but the DME was still severe in the optical coherence tomographic images. Then, one half the usual dose (25 mg) of spironolactone, a diuretic, was given and her macular edema was resolved. Her final visual acuity improved to 0.9 OD and 0.7 OS. We recommend that when a patient taking pioglitazone complains of decreased vision, the physician should promptly consult an ophthalmologist

    State-of-Arts Views on Response Control Technologies on Metal Space Structures

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    p. 277-288Recently various kinds of passive response control techniques are taken into practice for buildings in seismic areas, and they start affecting on the architectural design itself. These trend affects also on spatial structures, and application of such techniques to domes, truss structures, or tension structures are recently increasing. Folllowing previous descussions [1], this paper firstly present the recent varieties of architectural expressions using seismic response controll technologies in buildings. Then, several important progresses in the application of passive control technology for metal spatial structures are introduced by refering recently realized projects, followed by discussions on their response characteristics and easy response evaluation methods.Takeuchi, T.; Ogawa, T.; Kumagai, T. (2009). State-of-Arts Views on Response Control Technologies on Metal Space Structures. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/650

    Methylmercury promotes prostacyclin release from cultured human brain microvascular endothelial cells via induction of cyclooxygenase-2 through activation of the EGFR-p38 MAPK pathway by inhibiting protein tyrosine phosphatase 1B activity

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    Methylmercury is an environmental pollutant that exhibits neurotoxicity when ingested, primarily in the form of neuropathological lesions that localize along deep sulci and fissures, in addition to edematous and inflammatory changes in patient cerebrums. These conditions been known to give rise to a variety of ailments that have come to be collectively termed Minamata disease. Since prostaglandins I2 and E2 (PGI2 and PGE2) increase vascular permeability and contribute to the progression of inflammatory changes, we hypothesize that methylmercury induces the synthesis of these prostaglandins in brain microvascular endothelial cells and pericytes. To test this theory, human brain microvascular endothelial cells and pericytes were cultured and treated with methylmercury, after which the PGI2 and PGE2 released from endothelial cells and/or pericytes were quantified by enzyme-linked immunosorbent assay while protein and mRNA expressions in endothelial cells were analyzed by western blot analysis and real-time reverse transcription polymerase chain reaction, respectively. Experimental results indicate that methylmercury inhibits the activity of protein tyrosine phosphatase 1B, which in turn activates the epidermal growth factor receptor–p38 mitogen-activated protein kinase pathway that induces cyclooxygenase-2 expression. It was also found that the cyclic adenosine 3′,5′-monophosphate pathway, which can be activated by PGI2 and PGE2, is involved in methylmercury-induced cyclooxygenase-2 expression. Since it appears that protein tyrosine phosphatase 1 B serves as a sensor protein for methylmercury in these mechanisms, it is our belief that the results of the present study may provide additional insights into the molecular mechanisms responsible for edematous and inflammatory changes in the cerebrum of patients with Minamata disease

    Dynamic responses of cyclindrical lattice shell roofs under horizontal earthquake motions with arbitrary direction by shaking table test

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    p. 409-419This paper is intended as an investigation of the seismic response behavior of cylindrical lattice shell structures by shaking table tests. The seismic vibration tests are carried out using small scale models with shell span of 60 cm of cylindrical lattice shell roofs with substructure under horizontal motions in arbitrary direction. From the experimental results, the effects of difference of earthquake input direction and relationship between mechanical properties of roofs and substructures on response behavior of shell roofs are made clear. In addition, it is confirmed that the seismic response evaluation methods proposed in previous papers (Takeuchi et al. [1] ~ Takeuchi et al. [3]) apply to the responses subjected to earthquake motions with arbitrary direction.Kumagai, T.; Takeuchi, T.; Susuki, I.; Ogawa, T. (2009). Dynamic responses of cyclindrical lattice shell roofs under horizontal earthquake motions with arbitrary direction by shaking table test. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/653

    Response Evaluation of Seismically Isolated Lattice Domes using Amplification Factors

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    p. 355-365Seismic responses of raised lattice domes with substructures are known to be very complicated, and it is known that not only horizontal response but also vertical response is excited under horizontal seismic input. Such action causes damage on structures and nonstructural elements such as ceiling and suspended lightning equipments. A seismic isolation system is known to be effective to reduce such responses. In this paper, simple response evaluation methods for lattice domes supported by substructures with seismic isolation bearings are proposed using response amplification factors and linearization techniques with the same concept proposed by authors. Their validities are discussed against the results of time history analyses.Takamatsu, K.; Takeuchi, T.; Kumagai, T.; Ogawa, T. (2009). Response Evaluation of Seismically Isolated Lattice Domes using Amplification Factors. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/652

    A rechargeable lithium metal battery operating at intermediate temperatures using molten alkali bis(trifluoromethylsulfonyl)amide mixture as an electrolyte

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    The physicochemical properties of molten alkali bis(trifluoromethylsulfonyl)amide, MTFSI (M = Li, K, Cs), mixture (xLiTFSI = 0.20, xKTFSI = 0.10, xCsTFSI = 0.70) were studied to develop a new rechargeable lithium battery operating at intermediate temperature (100–180 °C). The viscosity and ionic conductivity of this melt at 150 °C are 87.2 cP and 14.2 mS cm⁻¹, respectively. The cyclic voltammetry revealed that the electrochemical window at 150 °C is as wide as 5.0 V, and that the electrochemical deposition/dissolution of lithium metal occurs at the cathode limit. A Li/MTFSI (M = Li, K, Cs)/LiFePO₄ cell showed an excellent cycle performance at a constant current rate of C/10 at 150 °C; 95% of the initial discharge capacity was maintained after 50 cycles. Except for the initial few cycles, the coulombic efficiencies were approximately 100% for all the cycles, indicating the stabilities of the molten MTFSI mixture and all the electrode materials
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