94 research outputs found

    Giant nonlinear conduction and thyristor-like negative derivative resistance in BaIrO3 single crystals

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    We synthesized single-crystalline samples of monoclinic BaIrO3 using a molten flux method, and measured their magnetization, resistivity, Seebeck coefficient and nonlinear voltage-current characteristics. The magnetization rapidly increases below a ferromagnetic transition temperature TC of 180 K, where the resistivity concomitantly shows a hump-type anomaly, followed by a sharp increase below 30 K. The Seebeck coefficient suddenly increases below TC, and shows linear temperature dependence below 50 K. A most striking feature of this compound is that the anomalously giant nonlinear conduction is observed below 30 K, where a small current density of 20 A/cm2 dramatically suppresses the sharp increase in resistivity to induce a metallic conduction down to 4 K.Comment: 10 pages, 4 figures Submitted to Physical Review Letter

    Magnetic Phase Diagram of Ce1-xErxAl2 intermetallic compounds

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    The magnetic and thermal properties of Ce1−xErxAl2 compounds have been studied using electrical resistivity and magnetic susceptibility measurements. The magnetic ordering temperature continuously changes with a change from antiferro-magnetism (CeAl2) to ferro-magnetism (ErAl2) appears. The magnetic ordering temperature is continuously changed as a function of Er concentration x. A spin glass behavior was found between x = 0.08 and 0.4. The magnetic phase diagram was compiled as a function of x.Embargo Period 12 month

    Thermal and magnetic properties in Ce1-xErxAl2 intermetallic compounds

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    The magnetic and thermal properties of Ce1−xErxAl2 compounds have been studied using specific heat, dc magnetization, and ac susceptibility measurements. All these compounds are isomorphic with the MgCu2 Laves phase, and the lattice parameter decreases almost linearly with the increasing Er concentration x. The dc magnetic susceptibility follows the Curie–Weiss law, and the Weiss temperature continuously changes from Θ = −24 K for x = 0 to Θ = 15 K for x = 1, indicating a change from antiferro-magnetism to ferromagnetism. Θ changes from negative to positive at around x = 0.2 where where a field-induced metamagnetic transition disappears. The magnetic ordering state continuously changes with the change in x from antiferromagnetic to ferromagnetic through a spin-glass-like behavior.Embargo Period 12 month

    Structure-activity relations of rosmarinic acid derivatives for the amyloid β aggregation inhibition and antioxidant properties

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    Amyloid-β aggregation inhibitors are expected to be therapeutic or prophylactic agents for Alzheimer\u27s disease. Rosmarinic acid, which is one of the main aggregation inhibitors derived from Lamiaceae, was employed as a lead compound and its 25 derivatives were synthesized. In this study,the structure-activity relations of rosmarinic acid derivatives for the amyloid-β aggregation inhibitory effect (MSHTS assay), antioxidant properties, and xanthine oxidase inhibition were evaluated. Among the tested compounds, compounds 16d and 19 were found to the most potent amyloid aggregation inhibitors. The SAR revealed that the necessity of the presence of the phenolic hydroxyl on one side of the molecule as well as the lipophilicity of the entire molecule. The importance of these structural properties was also supported by docking simulations

    Novel non-alcoholic steatohepatitis model with histopathological and insulin-resistant features

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    Although several non-alcoholic steatohepatitis (NASH) models have been reported to date, few of these models fully reflect the histopathology and pathophysiology of human NASH. The aim of this study was to establish a novel NASH model by feeding a high-fat (HF) diet and administering both carbon tetrachloride (CCl4) and the Liver X receptor agonist T0901317. Male C57BL/6J mice were divided into four groups (each n = 5): HF, HF + CCl4, HF + T0901317, and the novel NASH model (HF + CCl4 + T0901317). CCl4 (0.1 mL/kg) and T0901317 (2.5 mg/kg) were intraperitoneally administered four times and five times, respectively. The livers of the novel NASH model group presented a whitish colour. The serum levels of TNF-α and IL-6 were significantly increased in the novel NASH model group, and mice in this group exhibited histopathological features and insulin resistance reflective of NASH, i.e., macrovesicular hepatic steatosis, ballooning hepatocytes, Mallory-Denk bodies, lobular inflammation and fibrosis. The novel NASH model group presented significantly upregulated expression levels of mRNAs related to lipogenesis, oxidative stress, fibrosis and steatosis and significantly downregulated expression levels of mRNAs related to triglyceride export. We successfully established a novel experimental NASH model that exhibits similar histopathology and pathophysiology to human NASH

    Gene expression analysis in cadmium-stressed roots of a low cadmium-accumulating solanaceous plant, Solanum torvum

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    Solanum torvum Sw. cv. Torubamubiga (TB) is a low cadmium (Cd)-accumulating plant. To elucidate the molecular mechanisms of the Cd acclimation process in TB roots, transcriptional regulation was analysed in response to mild Cd treatment: 0.1 μM CdCl2 in hydroponic solution. A unigene set consisting of 6296 unigene sequences was constructed from 18 816 TB cDNAs. The distribution of functional categories was similar to tomato, while 330 unigenes were suggested to be TB specific. For expression profiling, the SuperSAGE method was adapted for use with Illumina sequencing technology. Expression tag libraries were constructed from Cd-treated (for 3 h, 1 d, and 3 d) and untreated roots, and 34 269 species of independent tags were collected. Moreover, 6237 tags were ascribed to the TB or eggplant (aubergine) unigene sequences. Time-course changes were examined, and 2049 up- and 2022 down-regulated tags were identified. Although no tags annotated to metal transporter genes were significantly regulated, a tag annotated to AtFRD3, a xylem-loading citrate transporter, was down-regulated. In addition to induction of heavy metal chaperone proteins, antioxidative and sulphur-assimilating enzymes were induced, confirming that oxidative stress developed even using a mild Cd concentration. Rapid repression of dehydration-related transcription factors and aquaporin isoforms suggests that dehydration stress is a potential constituent of Cd-induced biochemical impediments. These transcriptional changes were also confirmed by real-time reverse transcription-PCR. Further additions of TB unigene sequences and functional analysis of the regulated tags will reveal the molecular basis of the Cd acclimation process, including the low Cd-accumulating characteristics of TB

    Research and Science Today No. 2(4)/2012

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    Anomalous photoelectron angular distribution in ionization of Kr in intense ultraviolet laser fields

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    We investigate multiphoton ionization of Kr for the formation of the two spin-orbit split states 2P1/2^2P_{1/2} and 2P3/2^2P_{3/2} of Kr+^+ in intense ultraviolet femtosecond laser fields (λ\lambda\sim 398 nm, τ\tau\sim 50 fs). As the laser intensity increases from 8 to 39 TW cm2^{-2}, the photoelectron angular distribution (PAD) exhibits the anomalous enhancement in the direction perpendicular to the laser polarization. With the support of the time-dependent density functional theory taking account of the spin-orbit interaction, the measured anomalous PAD is ascribed to the autoionization to 2P3/2^2P_{3/2}
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