209 research outputs found

    Charge-Order Pattern of the Low-Temperature Phase of NaV2O5 Uniquely Determined by Resonant X-Ray Scattering from Monoclinic Single Domain

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    The present resonant x-ray scattering from each of monoclinically-split single domains of NaV2O5 has critically enhanced contrast between V4+ and V5+ ions strong enough to lead to unambiguous conclusion of the charge-order pattern of its low-temperature phase below Tc = 35 K. The zig-zag type charge-order patterns in the abab-plane previously confirmed have four kinds of configurations (A, A', B and B') and the stacking sequence along the c-axis is determined as the AAA'A' type by comparison with model calculations. By assigning the A and A' configurations to Ising spins, one can reasonably understand the previously discovered "devil's staircase"-type behavior with respect to the modulation of the layer-stacking sequences at high pressures and low temperatures, which very well resembles the global phase diagram theoretically predicted by the ANNNI model.Comment: 4 pages, 3 figure

    Systems consolidation requires postlearning activation of NMDA receptors in the medial prefrontal cortex in trace eyeblink conditioning.

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    The importance of the hippocampus in declarative memory is limited to recently acquired memory, and remotely acquired memory is believed to be stored somewhere in the neocortex. However, it remains unknown how the memory network is reorganized from a hippocampus-dependent form into a neocortex-dependent one. We reported previously that the medial prefrontal cortex (mPFC) is important for this neocortex-dependent remote memory in rat trace eyeblink conditioning. Here, we investigate the involvement of NMDA receptors in the mPFC in this reorganization and determine the time window of their contribution using chronic infusion of an antagonist into the mPFC, specifically during the postlearning consolidation period. The rats with blockade of the mPFC NMDA receptors during the first 1 or 2 weeks after learning showed a marked impairment in memory retention measured 6 weeks after learning, but relearned normally with subsequent conditioning. In contrast, the same treatment had no effect if it was performed during the third to fourth weeks or during the first day just after learning. The specificity of NMDA receptor blockade was confirmed by the reduced long-term potentiation in the hippocampal-prefrontal pathway in these rats. These results suggest that successful establishment of remotely acquired memory requires activation of NMDA receptors in the mPFC during at least the initial week of the postlearning period. Such NMDA receptor-dependent processes may mediate the maturation of neocortical networks that underlies permanent memory storage and serve as a way to reorganize memory circuitry to the neocortex-dependent form

    H-DBAS: Alternative splicing database of completely sequenced and manually annotated full-length cDNAs based on H-Invitational

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    The Human-transcriptome DataBase for Alternative Splicing (H-DBAS) is a specialized database of alternatively spliced human transcripts. In this database, each of the alternative splicing (AS) variants corresponds to a completely sequenced and carefully annotated human full-length cDNA, one of those collected for the H-Invitational human-transcriptome annotation meeting. H-DBAS contains 38 664 representative alternative splicing variants (RASVs) in 11 744 loci, in total. The data is retrievable by various features of AS, which were annotated according to manual annotations, such as by patterns of ASs, consequently invoked alternations in the encoded amino acids and affected protein motifs, GO terms, predicted subcellular localization signals and transmembrane domains. The database also records recently identified very complex patterns of AS, in which two distinct genes seemed to be bridged, nested or degenerated (multiple CDS): in all three cases, completely unrelated proteins are encoded by a single locus. By using AS Viewer, each AS event can be analyzed in the context of full-length cDNAs, enabling the user's empirical understanding of the relation between AS event and the consequent alternations in the encoded amino acid sequences together with various kinds of affected protein motifs. H-DBAS is accessible at

    Cloning of cDNA and genomic DNA for human cytochrome P-45011β

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    AbstractA full-length cDNA clone encoding steroid 11β-hydroxylase (P-45011β) has been isolated from a cDNA library derived from human adrenal tumor. The insert of the clone contains an open reading frame encoding a protein of 503 amino acid residues together with a 4 bp 5'-untranslated region and a 576 bp 3'-untranslated region to which a poly(A) tract is attached. The promoter region of the P-45011β gene has also been isolated from a genomic library derived from human pre-B cells. It contains a TATA box, a putative cAMP-responsive element, several repeated sequences and two sequence elements similar to the consensus sequence for binding of AP-1. A transient expression assay in Y-1 adrenal tumor cells demonstrates that the promoter activity is remarkably enhanced by treatment of the cells with cAMP. In addition, analysis using deletion mutants containing various lengths of the 5'-flanking region of the gene suggests that several cis-acting elements participate in transcriptional regulation of human P-45011β gene

    Effect of high-fat diet on phosphorus absorption

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    Objective: Dietary carbohydrate/fat ratio may affect phosphorus metabolism because both calcium and phosphorus are regulated by similar metabolic mechanisms, and a high-fat diet (HF) induces deleterious effects on the absorption of dietary calcium. We hypothesized that the HF induces an increase in phosphorus absorption; therefore, this study aimed to evaluate the effects of differences in the quantity and quality of dietary fat on phosphorus metabolism over the short and long term. Research Methods & Procedures: Eighteen 8-week-old Sprague-Dawley male rats were fed an isocaloric diet containing varied carbohydrate/fat energy ratio and sources of fat (control diet [Control], HF, and high saturated-fat diet [HF-SFA]). At 3 days and 7 weeks after the allocation and initiation of the test diets, feces and urine were collected and used for phosphorus and calcium measurement. Results: The fecal phosphorous concentration (F-Pi) was lower in the HF-SFA group than in the other two groups; however, the urine phosphorus concentration (U-Pi) was significantly higher in the HF-SFA group than the other two groups when the rats were fed over the short (p<0.01) and long term (p<0.01 vs Control group, p<0.05 vs HF group). There were no significant differences in type-IIa sodium-phosphate cotransporter (NaPi-2a) and type-IIc sodium-phosphate cotransporter (NaPi-2c) mRNA expression, which are renal phosphate transport-related genes; however, the expression of type-IIb sodium-phosphate cotransporter (NaPi-2b) and type-III sodium-phosphate cotransporter (Pit-1) mRNA in the duodenum was higher in the HF and HF-SFA groups than in the Control group (p<0.05), although there were no significant differences in these in the jejunum. Conclusions: Our results indicated that HF, particularly HF-SFA, increases intestinal phosphate absorption compared with Control
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