59 research outputs found

    Parity of polynomial multiplier sequences for the Chebyshev basis.

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    Abstract. We demonstrate that if p ∈ R[x] and p is not an even function, then {p(k)}∞ k=0 is not a multiplier sequence for the basis of Chebyshev polynomials of the first kind. We also give a characterization of geometric multiplier sequences for the Chebyshev basis.Ye

    Mechanism of imidazolium ionic liquids toxicity in Saccharomyces cerevisiae and rational engineering of a tolerant, xylose-fermenting strain

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    Additional file 3. Fermentation profiles of Y133 and Y133-IIL in the presence of 1Β % [BMIM]Cl at pH 6.5 and pH 5.0, and either aerobic or anaerobic conditions (nΒ =Β 3, MeanΒ Β±Β S.E, except nΒ =Β 2 for Y133 pH 6.5 anaerobic 72Β h)

    The American Association for the Surgery of Trauma renal injury grading scale: Implications of the 2018 revisions for injury reclassification and predicting bleeding interventions.

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    BackgroundIn 2018, the American Association for the Surgery of Trauma (AAST) published revisions to the renal injury grading system to reflect the increased reliance on computed tomography scans and non-operative management of high-grade renal trauma (HGRT). We aimed to evaluate how these revisions will change the grading of HGRT and if it outperforms the original 1989 grading in predicting bleeding control interventions.MethodsData on HGRT were collected from 14 Level-1 trauma centers from 2014 to 2017. Patients with initial computed tomography scans were included. Two radiologists reviewed the scans to regrade the injuries according to the 1989 and 2018 AAST grading systems. Descriptive statistics were used to assess grade reclassifications. Mixed-effect multivariable logistic regression was used to measure the predictive ability of each grading system. The areas under the curves were compared.ResultsOf the 322 injuries included, 27.0% were upgraded, 3.4% were downgraded, and 69.5% remained unchanged. Of the injuries graded as III or lower using the 1989 AAST, 33.5% were upgraded to grade IV using the 2018 AAST. Of the grade V injuries, 58.8% were downgraded using the 2018 AAST. There was no statistically significant difference in the overall areas under the curves between the 2018 and 1989 AAST grading system for predicting bleeding interventions (0.72 vs. 0.68, p = 0.34).ConclusionAbout one third of the injuries previously classified as grade III will be upgraded to grade IV using the 2018 AAST, which adds to the heterogeneity of grade IV injuries. Although the 2018 AAST grading provides more anatomic details on injury patterns and includes important radiologic findings, it did not outperform the 1989 AAST grading in predicting bleeding interventions.Level of evidencePrognostic and Epidemiological Study, level III

    Transcultural engagement with Polish memory of the Holocaust while watching Leszek Wosiewicz's Kornblumenblau

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    Kornblumenblau (Leszek Wosiewicz 1989) is a film that explores the experience of a Polish political prisoner interned at Auschwitz I. It particularly foregrounds issues related to Polish-Jewish relations during the Holocaust in its diegesis. Holocaust films are often discussed in relation to representation and the cultural specificity of their production context. However, this paper suggests thinking about film and topographies, the theme of this issue, not in relation to where a work is produced but in regards to the spectatorial space. It adopts a phenomenological approach to consider how, despite Kornblumenblau's particularly Polish themes, it might address the transcultural spectator and draw attention to the broader difficulties one faces when attempting to remember the Holocaust. Influenced particularly by the writing of Jennifer M. Barker and Laura U. Marks, this paper suggests that film possesses a body ¬¬- a display of intentionality, beyond those presented within the diegesis, which engages in dialogue with the spectator. During the experience of viewing Kornblumenblau, this filmic corporeality draws attention to the difficulties of confronting the Holocaust in particularly haptic ways, as the film points to the unreliability of visual historical sources, relates abject sensations to concentrationary spaces and breaks down as it confronts the scene of the gas chamber

    Werner Protein Is a Target of DNA-dependent Protein Kinase in Vivo and in Vitro , and Its Catalytic Activities Are Regulated by Phosphorylation

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    Human Werner Syndrome is characterized by early onset of aging, elevated chromosomal instability, and a high incidence of cancer. Werner protein (WRN) is a member of the recQ gene family, but unlike other members of the recQ family, it contains a unique 3'-->5' exonuclease activity. We have reported previously that human Ku heterodimer interacts physically with WRN and functionally stimulates WRN exonuclease activity. Because Ku and DNA-PKcs, the catalytic subunit of DNA-dependent protein kinase (DNA-PK), form a complex at DNA ends, we have now explored the possibility of functional modulation of WRN exonuclease activity by DNA-PK. We find that although DNA-PKcs alone does not affect the WRN exonuclease activity, the additional presence of Ku mediates a marked inhibition of it. The inhibition of WRN exonuclease by DNA-PKcs requires the kinase activity of DNA-PKcs. WRN is a target for DNA-PKcs phosphorylation, and this phosphorylation requires the presence of Ku. We also find that treatment of recombinant WRN with a Ser/Thr phosphatase enhances WRN exonuclease and helicase activities and that WRN catalytic activity can be inhibited by rephosphorylation of WRN with DNA-PK. Thus, the level of phosphorylation of WRN appears to regulate its catalytic activities. WRN forms a complex, both in vitro and in vivo, with DNA-PKC. WRN is phosphorylated in vivo after treatment of cells with DNA-damaging agents in a pathway that requires DNA-PKcs. Thus, WRN protein is a target for DNA-PK phosphorylation in vitro and in vivo, and this phosphorylation may be a way of regulating its different catalytic activities, possibly in the repair of DNA dsb

    Short-Term Exposure to Warm Microhabitats Could Explain Amphibian Persistence with Batrachochytrium dendrobatidis

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    Environmental conditions can alter the outcomes of symbiotic interactions. Many amphibian species have declined due to chytridiomycosis, caused by the pathogenic fungus Batrachochytrium dendrobatidis (Bd), but many others persist despite high Bd infection prevalence. This indicates that Bd's virulence is lower, or it may even be a commensal, in some hosts. In the Australian Wet Tropics, chytridiomycosis extirpated Litoria nannotis from high-elevation rain forests in the early 1990 s. Although the species is recolonizing many sites, no population has fully recovered. Litoria lorica disappeared from all known sites in the early 1990 s and was thought globally extinct, but a new population was discovered in 2008, in an upland dry forest habitat it shares with L. nannotis. All frogs of both species observed during three population censuses were apparently healthy, but most carried Bd. Frogs perch on sun-warmed rocks in dry forest streams, possibly keeping Bd infections below the lethal threshold attained in cooler rain forests. We tested whether short-term elevated temperatures can hamper Bd growth in vitro over one generation (four days). Simulating the temperatures available to frogs on strongly and moderately warmed rocks in dry forests, by incubating cultures at 33Β°C for one hour daily, reduced Bd growth below that of Bd held at 15Β°C constantly (representing rain forest habitats). Even small decreases in the exponential growth rate of Bd on hosts may contribute to the survival of frogs in dry forests

    Hypoxia Disruption of Vertebrate CNS Pathfinding through EphrinB2 Is Rescued by Magnesium

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    The mechanisms of hypoxic injury to the developing human brain are poorly understood, despite being a major cause of chronic neurodevelopmental impairments. Recent work in the invertebrate Caenorhabditis elegans has shown that hypoxia causes discrete axon pathfinding errors in certain interneurons and motorneurons. However, it is unknown whether developmental hypoxia would have similar effects in a vertebrate nervous system. We have found that developmental hypoxic injury disrupts pathfinding of forebrain neurons in zebrafish (Danio rerio), leading to errors in which commissural axons fail to cross the midline. The pathfinding defects result from activation of the hypoxia-inducible transcription factor (hif1) pathway and are mimicked by chemical inducers of the hif1 pathway or by expression of constitutively active hif1Ξ±. Further, we found that blocking transcriptional activation by hif1Ξ± helped prevent the guidance defects. We identified ephrinB2a as a target of hif1 pathway activation, showed that knock-down of ephrinB2a rescued the guidance errors, and showed that the receptor ephA4a is expressed in a pattern complementary to the misrouting axons. By targeting a constitutively active form of ephrinB2a to specific neurons, we found that ephrinB2a mediates the pathfinding errors via a reverse-signaling mechanism. Finally, magnesium sulfate, used to improve neurodevelopmental outcomes in preterm births, protects against pathfinding errors by preventing upregulation of ephrinB2a. These results demonstrate that evolutionarily conserved genetic pathways regulate connectivity changes in the CNS in response to hypoxia, and they support a potential neuroprotective role for magnesium
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