176 research outputs found

    High-temperature thermoelectric properties of the double-perovskite ruthenium oxide (Sr1x_{1-x}Lax_x)2_2ErRuO6_6

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    We have prepared polycrystalline samples of (Sr1x_{1-x}Lax_x)2_2ErRuO6_6 and (Sr1x_{1-x}Lax_x)2_2YRuO6_6, and have measured the resistivity, Seebeck coefficient, thermal conductivity, susceptibility and x-ray absorption in order to evaluate the electronic states and thermoelectric properties of the doped double-perovskite ruthenates. We have observed a large Seebeck coefficient of -160 μ\muV/K and a low thermal conductivity of 7 mW/cmK for xx=0.1 at 800 K in air. These two values are suitable for efficient oxide thermoelectrics, although the resistivity is still as high as 1 Ω\Omegacm. From the susceptibility and x-ray absorption measurements, we find that the doped electrons exist as Ru4+^{4+} in the low spin state. On the basis of the measured results, the electronic states and the conduction mechanism are discussed.Comment: 6 pages, 4 figures, J. Appl. Phys. (accepted

    Novel Charge Ordering in the Trimer Iridium Oxide BaIrO3

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    We have prepared polycrystalline samples of the trimer Ir oxide BaIrO3 with face-shared Ir3O12 trimers, and have investigated the origin of the phase transition at 182 K by measuring resistivity, thermopower, magnetization and synchrotron x-ray diffraction. We propose a possible electronic model and transition mechanism, starting from a localized electron picture on the basis of the Rietveld refinement. Within this model, BaIrO3 can be basically regarded as a Mott insulator, when the Ir3O12 trimer is identified to one pseudo-atom or one lattice site. The transition can be viewed as a transition from the Mott insulator phase to a kind of charge ordered insulator phase.Comment: 8 pages 5 figures, Crystals (in press

    Long-term outcome of severe stroke patients : Is the ADL status at discharge from a stroke center indicative of the long-term outcome?

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    The objective of this study was to examine the possibility of predicting the longterm outcome of severe stroke patients from the ADL status at discharge. The design is a retrospective observational study in the stroke center at Tokushima University Hospital. Severe stroke patients at discharge with Barthel Index (BI) scores 40 (N=51) were divided into two subgroups retrospectively, improved and unimproved. The Functional Independence Measure (FIM) and BI were analyzed at discharge, 3 and 6 months after onset. Correlation analysis between BI and FIM showed good correlation, especially between BI and motor FIM (mFIM). In conclusion, the ADL status at discharge from a stroke center is not definitely indicative of the long-term outcome, although good recovery of severe stroke cases was observed in males and younger patients, and in patients with motor FIM score 25. This result shows that the first 3 months after the attack should be regarded as an important time window for intensive rehabilitation

    MiR-33a is a therapeutic target in SPG4-related hereditary spastic paraplegia human neurons

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    Recent reports, including ours, have indicated that microRNA (miR)-33 located within the intron of sterol regulatory element binding protein (SREBP) 2 controls cholesterol homeostasis and can be a potential therapeutic target for the treatment of atherosclerosis. Here, we show that SPAST, which encodes a microtubule-severing protein called SPASTIN, was a novel target gene of miR-33 in human. Actually, the miR-33 binding site in the SPAST 3′-UTR is conserved not in mice but in mid to large mammals, and it is impossible to clarify the role of miR-33 on SPAST in mice. We demonstrated that inhibition of miR-33a, a major form of miR-33 in human neurons, via locked nucleic acid (LNA)-anti-miR ameliorated the pathological phenotype in hereditary spastic paraplegia (HSP)-SPG4 patient induced pluripotent stem cell (iPSC)-derived cortical neurons. Thus, miR-33a can be a potential therapeutic target for the treatment of HSP-SPG4

    Gait and posture assessments of a patient treated with deep brain stimulation in dystonia using three-dimensional motion analysis systems

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    Kinesiologic analysis of gait disorders, postural instabilities and abnormal movements is quite difficult to assess objectively by clinical observation, such as by specific scale and video recordings. In this study, we reported one of the aspects of the usefulness of three-dimensional motion analysis (Vicon Systems, Oxford, United Kingdom), which can measure inclusive data of movement disorders and substitute for conventional assessments. A 49-year-old man who had various dystonic symptoms, mainly on his left side of the body, responded well to deep brain stimulation (DBS). The examination quantified how the involuntary movements or other symptoms with dystonia changed before and after treatments

    Relationship between Barthel Index scores during the acute phase of rehabilitation and subsequent ADL in stroke patients

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    The Barthel Index (BI) cannot be used to measure initial stroke severity or by extension, to stratify patients by severity in acute stroke trials because most patients are bedbound in the first few hours after stroke, either by their deficit or by medical directive. Our objectives were to clarify the threshold of acute BI for use in the prediction of subsequent independence in activities of daily living (ADL) and to assist in the definition of acute stroke rehabilitation goals. Subjects comprised 78 patients out of 191 inpatients admitted with acute stroke at our hospital during 2006-2007. The BI ADL score was divided into 2 ranges (BI≧60 and≦40), in a process similar to previous studies. During the acute period (from onset to approximately 3 weeks), all patients with a BI≧40 could improve their ADL in 6 months. Patients with a BI≦40 exhibited two ADL recovery outcomes (improved and no change) at 6 months. We also found that the skill level of basic activities related to standing was significant indicator of BI improvement (P<0.001). BI scores determined at approximately 3 weeks were reliable predictors of ADL disabilities at 6 months
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