44 research outputs found

    A New Approach for the Preparation of Variable Valence Rare Earth Alloys from Nano Rare Earth Oxides at a Low Temperature in Molten Salt

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    The solubility of RE2O3 (RE = Eu, Sm, and Yb) with variable valence in molten salts is extremely low. It is impossible to directly obtain variable valence metals or alloys from RE2O3 using electrolysis in molten salts. We describe a new approach for the preparation of variable valence rare earth alloys from nano rare earth oxide. The excellent dispersion of nano–Eu2O3 in LiCl–KCl melts was clearly observed using a luminescent feature of Eu3+ as a probe. The ratio of solubility of nano-Sm2O3/common Sm2O3 is 16.98. Electrochemical behavior of RE2O3 on a molybdenum and Al electrode in LiCl–KCl melts containing AlCl3 at 480 °C was investigated by different electrochemical techniques, such as cyclic voltammetry (CV), square wave voltammetry, and chronopotentiometry. Prior to the reduction peak of Al, the reduction peaks of Sm(III)/Sm(II), Yb(III)/Yb(II), and Eu(III)/Eu(II) were observed at about −0.85, −0.45, and 0.39 V insquare wave voltammetry, respectively. The underpotential deposition of RE on pre-deposited aluminum leads to the formation of Al–RE alloy. The structure, morphology, and energy dispersion analysis of the deposit obtained by potentiostatic electrolysis are analyzed. Al2Sm and Al3Sm alloys were successfully obtained from nano–Sm2O3

    Listening as productive skills: Reinventing classroom tasks

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    The article revisits the role played by listening skills in second language learning by challenging the perception of listening as a receptive skill. It argues that listening can be made productive by incorporating drama in classroom tasks to bring out more productive features of learning. To instantiate the implementation of drama, a listening activity is proposed with a framework. The article opens a new dialogue in scholarly characterisation of language skills through re-visualising what learners can perform during listening tasks as well as how this performance can stretch our conventional thinking about the nature of language practice

    Investigating learner silent and verbal responses to tasks

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    This article reports a study on EFL/ESL learner perceptions of classroom tasks with reference to verbal or non-verbal participation, that is, how much speech and silence would be employed in response to a rage of task types. Data were collected from 260 learners from Indonesia and the Philippines. The article begins by explaining why silence and speech are the focus of the discussion. Secondly, it shares the literature review on how silence works in language learning and why it deserves a place in classroom teaching. Thirdly, it highlights classroom tasks that trigger silent processing and explain why this is the case. Finally, there are recommendations for task design in which similar activity types are introduced to assist the learning of reflective students

    Genetic Connection between Hyperglycemia and Carotid Atherosclerosis in Hyperlipidemic Mice

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    Type 2 diabetes (T2D) is a major risk for atherosclerosis and its complications. Apoe-null (Apoe−/−) mouse strains exhibit a wide range of variations in susceptibility to T2D and carotid atherosclerosis, with the latter being a major cause of ischemic stroke. To identify genetic connections between T2D and carotid atherosclerosis, 145 male F2 mice were generated from LP/J and BALB/cJ Apoe−/− mice and fed 12 weeks of a Western diet. Atherosclerotic lesions in the carotid arteries, fasting, and non-fasting plasma glucose levels were measured, and genotyping was performed using miniMUGA arrays. Two significant QTL (quantitative trait loci) on chromosomes (Chr) 6 and 15 were identified for carotid lesions. The Chr15 QTL coincided precisely with QTL Bglu20 for fasting and non-fasting glucose levels. Carotid lesion sizes showed a trend toward correlation with fasting and non-fasting glucose levels in F2 mice. The Chr15 QTL for carotid lesions was suppressed after excluding the influence from fasting or non-fasting glucose. Likely candidate genes for the causal association were Tnfrsf11b, Deptor, and Gsdmc2. These results demonstrate a causative role for hyperglycemia in the development of carotid atherosclerosis in hyperlipidemic mice

    Antioxidative components of tanshen (Salvia miltiorhiza Bung)

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    The role of Shc and insulin-like growth factor 1 receptor in mediating the translocation of estrogen receptor α to the plasma membrane

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    Our previous studies demonstrated that 17β-estradiol (E2) rapidly induces the interaction of estrogen receptor α (ERα) with the adapter protein Shc, the translocation of ERα to the cell membrane, and the formation of dynamic membrane structures in MCF-7 breast cancer cells. The present study examined how E2 causes ERα to translocate to the region of the plasma membrane and focused on mechanisms whereby Shc and the insulin-like growth factor-1 receptor (IGF-1R) mediate this process. Shc physically interacts with IGF-1R in the plasma membrane, and E2 activates IGF-1R. We reasoned that ERα, when bound to Shc, would be directed to the region of the plasma membrane by the same processes, causing membrane translocation of Shc. We confirmed that E2 rapidly induced IGF-1R phosphorylation and demonstrated that E2 induced formation of a ternary protein complex among Shc, ERα, and IGF-1R. Knock down of Shc with a specific small inhibitory RNA decreased the association of ERα with IGF-1R by 87%, suggesting that Shc is a crucial molecule in the formation of this ternary complex. Confocal microscopy studies provided further confirmation of the functional roles of Shc and the IGF-1R in the translocation of ERα to the region of the membrane. Down-regulation of Shc, ERα, or IGF-1R with specific small inhibitory RNAs all blocked E2-induced mitogen-activated protein kinase phosphorylation. Together, our results demonstrate that Shc and IGF-1R serve as key elements in the translocation of ERα to the cell membrane and in the facilitation of ERα-mediated rapid E2 action

    Microarray analysis of gene expression in mouse aorta reveals role of the calcium signaling pathway in control of atherosclerosis susceptibility

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    Inbred mouse strains C57BL/6J (B6) and C3H/HeJ (C3H) exhibit a marked difference in atherosclerotic lesion formation when deficient in apolipoprotein E (apoE−/−), and the arterial wall has been identified as a source of the difference in atherosclerosis susceptibility. In the present study, differences in gene expression in aortic walls of the two strains were analyzed by microarrays. Total RNA was extracted from the aorta of 6-wk-old female B6 and C3H apoE−/− mice fed a chow or Western diet. There were 1,514 genes in chow fed mice and 590 genes in Western fed mice that were found to be differentially expressed between the two strains. Pathway analysis of differentially expressed genes suggested a role for the calcium signaling pathway in regulating atherosclerosis susceptibility. Oxidized LDL (oxLDL) induced a dose-dependent rise in cytosolic calcium levels in B6 endothelial cells. oxLDL-induced monocyte chemoattractant protein-1 production was inhibited by pretreatment with calcium chelator EGTA or intracellular calcium trapping compound BAPTA, indicating that calcium ions mediate the effect of oxLDL on monocyte chemoattractant protein-1 induction. The present findings demonstrate involvement of the calcium signaling pathway in the inflammatory process of atherogenesis
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