865 research outputs found

    Sub-Arcsecond Near-Infrared Images of Massive Star Formation Region NGC 6334 V

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    We present high spatial resolution (0\farcs3) polarimetric images in the HH and KK bands and direct images in the LL' and MM' bands of the NGC 6334 V infrared nebulae. The images show complex structures including the multi-shells and various knots in the nebulae. The appearances and colors of the eastern and western nebulae differ considerably. Our polarization images also show differences between the illuminating sources of the nebulae: the eastern nebula is illuminated by a deeply embedded mid-infrared source, KDJ 4, and the western nebula by our newly detected near-infrared source, WN-A1. The degree of polarization of the nebulae is very large, up to 70% at KK and 60% at HH, which is consistent with a single scattering of near-infrared radiation from each source at the walls of the mass outflows

    Políticas energéticas no Estado do Amazonas: implicações e questões em face do meio ambiente

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    Questionar a geração de energia e suas implicações políticas em face das sustentabilidades econômica, ambiental e social, significa verificar que as políticas do Estado nacional e local para a produção de energia elétrica ainda valorizam o modelo monomatricial implantado na década de 60 com a geração de energia pelas hidrelétricas

    Identification of PLXDC1 and PLXDC2 as the transmembrane receptors for the multifunctional factor PEDF.

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    Pigment Epithelium Derived Factor (PEDF) is a secreted factor that has broad biological activities. It was first identified as a neurotrophic factor and later as the most potent natural antiangiogenic factor, a stem cell niche factor, and an inhibitor of cancer cell growth. Numerous animal models demonstrated its therapeutic value in treating blinding diseases and diverse cancer types. A long-standing challenge is to reveal how PEDF acts on its target cells and the identities of the cell-surface receptors responsible for its activities. Here we report the identification of transmembrane proteins PLXDC1 and PLXDC2 as cell-surface receptors for PEDF. Using distinct cellular models, we demonstrate their cell type-specific receptor activities through loss of function and gain of function studies. Our experiments suggest that PEDF receptors form homooligomers under basal conditions, and PEDF dissociates the homooligomer to activate the receptors. Mutations in the intracellular domain can have profound effects on receptor activities

    Cell type-dependent gene regulation by Staufen2 in conjunction with Upf1

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    <p>Abstract</p> <p>Background</p> <p>Staufen2 (Stau2), a double-stranded RNA-binding protein, is a component of neuronal RNA granules, which are dendritic mRNA transport machines. Although Stau2 is thought to be involved in the dendritic targeting of several mRNAs in neurons, the mechanism whereby Stau2 regulates these mRNAs is unknown. To elucidate the functions of Stau2, we screened for novel binding partners by affinity purification of GST-tagged Stau2 from 293F cells.</p> <p>Results</p> <p>Three RNA helicases, RNA helicase A, Upf1 and Mov10, were identified in Stau2-containing complexes. We focused our studies on Upf1, a key player in nonsense-mediated mRNA decay. Stau2 was found to bind directly to Upf1 in an RNA-independent manner <it>in vitro</it>. Tethering Stau2 to the 3'-untranslated region (UTR) of a reporter gene had little effect on its expression in HeLa cells. In contrast, when the same tethering assay was performed in 293F cells, we observed an increase in reporter protein levels. This upregulation of protein expression by Stau2 turned out to be dependent on Upf1. Moreover, we found that in 293F cells, Stau2 upregulates the reporter mRNA level in an Upf1-independent manner.</p> <p>Conclusions</p> <p>These results indicate that the recruitment of Stau2 alone or in combination with Upf1 differentially affects the fate of mRNAs. Moreover, the results suggest that Stau2-mediated fate determination could be executed in a cell type-specific manner.</p

    Early hemoperfusion with an immobilized polymyxin B fiber column eliminates humoral mediators and improves pulmonary oxygenation

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    INTRODUCTION: The objective of this study was to clarify the efficacy and mechanism of action of direct hemoperfusion with an immobilized polymyxin B fiber column (DHP-PMX) in patients with acute lung injury or acute respiratory distress syndrome caused by sepsis. METHOD: Thirty-six patients with sepsis were included. In each patient a thermodilution catheter was inserted, and the oxygen delivery index and oxygen consumption index were measured. DHP-PMX was performed in patients with a normal oxygen delivery index and oxygen consumption index (> 500 ml/minute per m(2 )and >120 ml/minute per m(2), respectively). The Acute Physiology and Chronic Health Evaluation II score was used as an index of the severity of sepsis, and survival was assessed after 1 month. The humoral mediators measured were the chemokine IL-8, plasminogen activator inhibitor-1, and neutrophil elastase (NE). These mediators were measured before DHP-PMX treatment, and at 24, 48, and 78 hours after the start of treatment. The arterial oxygen tension (PaO(2))/fractional inspired oxygen (FiO(2)) ratio was measured before DHP-PMX treatment and at 24, 48, 72, 92, and 120 hours after the start of treatment. RESULTS: All patients remained alive after 1 month. Before DHP-PMX treatment, the Acute Physiology and Chronic Health Evaluation II score was 24 ± 2.0, the IL-8 level was 54 ± 15.8 pg/ml, plasminogen activator inhibitor-1 was 133 ± 28.1 ng/ml, and NE was 418 ± 72.1 μg/l. These three humoral mediators began to decrease from 24 hours after DHP-PMX treatment, and the decline became significant from 48 hours onward. The PaO(2)/FiO(2 )ratio was 244 ± 26.3 before DHP-PMX treatment but improved significantly from 96 hours onward. There were significant negative correlations between the PaO(2)/FiO(2 )ratio and blood levels of NE and IL-8. CONCLUSION: The mechanism of action of DHP-PMX is still not fully understood, but we report the following findings. The mean blood levels of plasminogen activator inhibitor-1, NE, and IL-8 were significantly decreased from 48 hours after DHP-PMX treatment. The mean PaO(2)/FiO(2 )ratio was significantly improved from 96 hours after DHP-PMX treatment. Improvement in the PaO(2)/FiO(2 )ratio appeared to be related to the decreases in blood NE and IL-8 levels

    Exportin-5 orthologues are functionally divergent among species

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    Exportin-5, an evolutionarily conserved nuclear export factor belonging to the importin-β family of proteins, is known to play a role in the nuclear export of small noncoding RNAs such as precursors of microRNA, viral minihelix RNA and a subset of tRNAs in mammalian cells. In this study, we show that the exportin-5 orthologues from different species such as human, fruit fly and yeast exhibit diverged functions. We found that Msn5p, a yeast exportin-5 orthologue, binds double-stranded RNAs and that it prefers a shorter 22 nt, double-stranded RNA to ∼80 nt pre-miRNA, even though both of these RNAs share a similar terminal structure. Furthermore, we found that Drosophila exportin-5 binds pre-miRNAs and that amongst the exportin-5 orthologues tested, it shows the highest affinity for tRNAs. The knockdown of Drosophila exportin-5 in cultured cells decreased the amounts of tRNA as well as miRNA, whereas the knock down of human exportin-5 in cultured cells affected only miRNA but not tRNA levels. These results indicate that double-stranded RNA binding ability is an inherited functional characteristic of the exportin-5 orthologues and that Drosophila exportin-5 functions as an exporter of tRNAs as well as pre-miRNAs in the fruit fly that lacks the orthologous gene for exportin-t

    The Counseling Training Environment Scale (CTES) : development of a self-report measure to assess counseling training environment

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    Based on Bronfenbrenner's (1979, 1992) ecological framework, the Counseling Training Environment Scale (CTES) was developed as a self-report measure that assesses the learning and training environment of counseling and related mental health training programs as perceived by current students. A two-phase mixed-methods design was used to create and psychometrically evaluate the CTES: (a) item development, and (b) assessment of the outcomes to examine for preliminary evidence of validity and reliability. The results of the item development and content validation process yielded 128 items, of which 34 were used for the final intact version of the CTES. A confirmatory factor analysis (CFA) was conducted on four models of the CTES: (a) 34-item single-factor model, (b) 34-item five-factor model, (c) 26-item modified five-factor model, and (d) 24-item modified single-factor model. Results of the CFA suggest that despite not conforming to the hypothesized model of Bronfenbrenner's (1979, 1992) ecological theory, the data gathered from the modified 24-item single-factor CTES demonstrated the best fit on the following fit indices: NNFI (.95), CFI (.96), SRMR (.04), and RMSEA (.04). The modified 24-item CTES was also found to demonstrate strong reliability and temporal stability as demonstrated through Classical Test Theory analyses (a = .92) and test-retest reliability (r = .90, p&lt; .01, two-tailed)
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