537 research outputs found

    Synergistic multi-doping effects on the Li7La3Zr2O12 solid electrolyte for fast lithium ion conduction.

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    Here, we investigate the doping effects on the lithium ion transport behavior in garnet Li7La3Zr2O12 (LLZO) from the combined experimental and theoretical approach. The concentration of Li ion vacancy generated by the inclusion of aliovalent dopants such as Al(3+) plays a key role in stabilizing the cubic LLZO. However, it is found that the site preference of Al in 24d position hinders the three dimensionally connected Li ion movement when heavily doped according to the structural refinement and the DFT calculations. In this report, we demonstrate that the multi-doping using additional Ta dopants into the Al-doped LLZO shifts the most energetically favorable sites of Al in the crystal structure from 24d to 96 h Li site, thereby providing more open space for Li ion transport. As a result of these synergistic effects, the multi-doped LLZO shows about three times higher ionic conductivity of 6.14 × 10(-4) S cm(-1) than that of the singly-doped LLZO with a much less efforts in stabilizing cubic phases in the synthetic condition

    Development of a hybrid magnetic resonance/computed tomography-compatible phantom for magnetic resonance guided radiotherapy

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    The purpose of the present study was to develop a hybrid magnetic resonance/computed tomography (MR/CT)-compatible phantom and tissue-equivalent materials for each MR and CT image. Therefore, the essential requirements necessary for the development of a hybrid MR/CT-compatible phantom were determined and the development process is described. A total of 12 different tissue-equivalent materials for each MR and CT image were developed from chemical components. The uniformity of each sample was calculated. The developed phantom was designed to use 14 plugs that contained various tissue-equivalent materials. Measurement using the developed phantom was performed using a 3.0-T scanner with 32 channels and a Somatom Sensation 64. The maximum percentage difference of the signal intensity (SI) value on MR images after adding K2CO3 was 3.31%. Additionally, the uniformity of each tissue was evaluated by calculating the percent image uniformity (%PIU) of the MR image, which was 82.18 ±1.87% with 83% acceptance, and the average circular-shaped regions of interest (ROIs) on CT images for all samples were within ±5 Hounsfield units (HU). Also, dosimetric evaluation was performed. The percentage differences of each tissue-equivalent sample for average dose ranged from -0.76 to 0.21%. A hybrid MR/CT-compatible phantom for MR and CT was investigated as the first trial in this field of radiation oncology and medical physics

    Insulin and glucagon secretions, and morphological change of pancreatic islets in OLETF rats, a model of type 2 diabetes mellitus.

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    This study was performed to observe the changes of glucose-related hormones and the morphological change including ultrastructure of the pancreatic islets in the male Otsuka Long-Evans Tokushima Fatty rat. Area under the curve (AUC) of glucose at the 30th (709 plus minus 73 mg.h/dL) and at the 40th week (746 plus minus 87 mg.h/ dL) of age were significantly higher than that at the 10th week (360 plus minus 25 mg.h/ dL). AUC of insulin of the 10th week was 2.4 plus minus 0.9 ng.h/mL, increased gradually to 10.8 plus minus 8.3 ng.h/mL at the 30th week, and decreased to 1.8 plus minus 1.2 ng.h/mL at the 40th week. The size of islet was increased at 20th week of age and the distribution of peripheral alpha cells and central beta cells at the 10th and 20th weeks was changed to a mixed pattern at the 40th week. On electron microscopic examination, beta cells at the 20th week showed many immature secretory granules, increased mitochondria, and hypertrophied Golgi complex and endoplasmic reticulum. At the 40th week, beta cell contained scanty intracellular organelles and secretory granules and apoptosis of acinar cell was observed. In conclusion, as diabetes progressed, increased secretion of insulin was accompanied by increases in size of islets and number of beta-cells in male OLETF rats showing obese type 2 diabetes. However, these compensatory changes could not overcome the requirement of insulin according to the continuous hyperglycemia after development of diabetes

    An autoregulatory loop controlling orphan nuclear receptor DAX-1 gene expression by orphan nuclear receptor ERRγ

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    The estrogen receptor-related receptor gamma (ERRγ/ERR3/NR3B3) is a member of the nuclear receptor superfamily that activates transcription in the absence of ligand. However, the detailed mechanism of gene regulation by ERRγ is not fully understood. In this study we have found that the orphan nuclear receptor ERRγ activates the DAX-1 promoter, which, in turn, represses transactivation by ERRγ. Serial deletions of mouse DAX-1 (mDAX-1) gene promoter have revealed that the region responding to ERRγ is located between −129 and −121 bp and −334 and −326 bp. Gel shift assays and chromatin immunoprecipitation (ChIP) assays demonstrated that ERRγ binds directly to the mDAX-1 promoter. Site-directed mutagenesis results demonstrated that ERRE1 (−129 to −121 bp) is more important than ERRE2 (−334 to −326 bp) which is not conserved in the human DAX-1 promoter. In addition, adenovirus-mediated overexpression of ERRγ induced DAX-1 gene expression in MCF-7 breast cancer cells that co-expressed ERRγ and DAX-1. Moreover, yeast two-hybrid and glutathione S-transferase (GST)-pull down assays demonstrated that DAX-1 physically interacted with ERRγ and inhibited ERRγ transactivation, and that this interaction was dependent on the AF-2 domain of ERRγ. In addition, in vitro competition assays showed that DAX-1 inhibited PGC-1α mediated ERRγ transactivation, via competition between these two factors for the AF-2 binding domain. We thus propose a novel autoregulatory loop that controls DAX-1 gene expression by ERRγ

    Cerebral Infarction in IgG Multiple Myeloma with Hyperviscosity

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    Cerebral infarction is an uncommon complication in multiple myeloma with hyperviscosity. Serum hyperviscosity may cause a variety of clinical manifestations including bleeding from mucosal membranes, congestive heart failure, retinopathy, and various neurologic deficits. These manifestations have been attributed to the presence of large quantities of asymmetrical molecules of high molecular weight in the serum. We recently experienced a case of multiple myeloma with acute cerebral infarction, which caused by hyperviscosity, as an initial manifestation in IgG multiple myeloma, and reviewed the relevant literature of myeloma presenting with the stroke. A 68-yr-old woman abruptly developed hypesthesia and monoplegia in the left leg. The stroke confirmed by the brain MRI and MR angiography, which revealed acute infarction at the right anterior cerebral artery territory. On admission, routine blood tests showed a slight decrease in hemoglobin and a marked increase in erythrocyte sedimentation rate. Peripheral blood smear, serum protein electrophoresis, serum visocity, and bone marrow aspiration showed that she had IgG multiple myeloma with hyperviscosity. She was treated by chemotherapy with cyclophosphamide and discharged with the improved clinical condition

    MiR-9 Controls Chemotactic Activity of Cord Blood CD34⁺ Cells by Repressing CXCR4 Expression

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    Improved approaches for promoting umbilical cord blood (CB) hematopoietic stem cell (HSC) homing are clinically important to enhance engraftment of CB-HSCs. Clinical transplantation of CB-HSCs is used to treat a wide range of disorders. However, an improved understanding of HSC chemotaxis is needed for facilitation of the engraftment process. We found that ectopic overexpression of miR-9 and antisense-miR-9 respectively down- and up-regulated C-X-C chemokine receptor type 4 (CXCR4) expression in CB-CD34+ cells as well as in 293T and TF-1 cell lines. Since CXCR4 is a specific receptor for the stromal cell derived factor-1 (SDF-1) chemotactic factor, we investigated whether sense miR-9 and antisense miR-9 influenced CXCR4-mediated chemotactic mobility of primary CB CD34+ cells and TF-1 cells. Ectopic overexpression of sense miR-9 and antisense miR-9 respectively down- and up-regulated SDF-1-mediated chemotactic cell mobility. To our knowledge, this study is the first to report that miR-9 may play a role in regulating CXCR4 expression and SDF-1-mediated chemotactic activity of CB CD34+ cells

    Identification of a novel ubiquitin binding site of STAM1 VHS domain by NMR spectroscopy

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    AbstractInteraction between the signal-transducing adapter molecule 1 (STAM1) Vps27/Hrs/Stam (VHS) domain and ubiquitin was investigated by nuclear magnetic resonance (NMR) spectroscopy. NMR evidence showed that the structure of STAM1 VHS domain resembles that of other VHS domains, especially the homologous domain of STAM2. We found that the VHS domain binds to ubiquitin via its hydrophobic patch consisting of N-terminus of helix 2 and C-terminus of helix 4 in which Trp26 on helix 2 plays a pivotal role in the binding. The binding between VHS and ubiquitin seems to be very similar to that between ubiquitin associated domain (UBA) and ubiquitin, however, the direction of α-helices involved in the ubiquitin binding is opposite. Here, we propose a novel ubiquitin binding site and the manner of ubiquitin recognition of the STAM1 VHS domain.Structured summaryMINT-6804185:STAM1 (uniprotkb:Q92783) binds (MI:0407) to ubiquitin (uniprotkb:P62988) by nuclear magnetic resonance (MI:0077

    The possible roles of hyperpolarization-activated cyclic nucleotide channels in regulating pacemaker activity in colonic interstitial cells of Cajal

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    BACKGROUND: Hyperpolarization-activated cyclic nucleotide (HCN) channels are pacemaker channels that regulate heart rate and neuronal rhythm in spontaneously active cardiac and neuronal cells. Interstitial cells of Cajal (ICCs) are also spontaneously active pacemaker cells in the gastrointestinal tract. Here, we investigated the existence of HCN channel and its role on pacemaker activity in colonic ICCs. METHODS: We performed whole-cell patch clamp, RT-PCR, and Ca(2+)-imaging in cultured ICCs from mouse mid colon. RESULTS: SQ-22536 and dideoxyadenosine (adenylate cyclase inhibitors) decreased the frequency of pacemaker potentials, whereas both rolipram (cAMP-specific phosphodiesterase inhibitor) and cell-permeable 8-bromo-cAMP increased the frequency of pacemaker potentials. CsCl, ZD7288, zatebradine, clonidine (HCN channel blockers), and genistein (a tyrosine kinase inhibitor) suppressed the pacemaker activity. RT-PCR revealed expression of HCN1 and HCN3 channels in c-kit and Ano1 positive colonic ICCs. In recordings of spontaneous intracellular Ca(2+) [Ca(2+)](i) oscillations, rolipram and 8-bromo-cAMP increased [Ca(2+)](i) oscillations, whereas SQ-22536, CsCl, ZD7288, and genistein decreased [Ca(2+)](i) oscillations. CONCLUSIONS: HCN channels in colonic ICCs are tonically activated by basal cAMP production and participate in regulation of pacemaking activity
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