431 research outputs found
Structural insight into nucleotide recognition by human death-associated protein kinase
The crystal structures of DAPK–ADP–Mg2+ and DAPK–AMP-PNP–Mg2+ complexes were determined at 1.85 and 2.00 Å resolution, respectively. Comparison of the two nucleotide-bound states with apo DAPK revealed localized changes in the glycine-rich loop region that were indicative of a transition from a more open state to a more closed state on binding of the nucleotide substrate and to an intermediate state with the bound nucleotide product
Site-directed mutagenesis of the glycine-rich loop of death associated protein kinase (DAPK) identifies it as a key structure for catalytic activity
AbstractDeath associated protein kinase (DAPK) is a calmodulin (CaM)-regulated protein kinase that is a therapeutic target for central nervous system (CNS) disorders. We report here the results of studies that test the hypothesis of McNamara et al. (2009) that conformational selection in DAPK's glycine-rich region is key for catalytic activity. The hypothesis was tested by site-directed mutagenesis of glutamine-23 (Q23) in the middle of this loop. The glycine-rich loop exhibits localized differences in structure among DAPK conformations that correlate with different stages of the catalytic cycle. Changing the Q23 to a Valine (V23), found at the corresponding position in another CaM regulated protein kinase, results in a reduced catalytic efficiency. High resolution X-ray crystal structures of various conformations of the Q23V mutant DAPK and their superimposition with the corresponding conformations from wild type catalytic domain reveal localized changes in the glycine-rich region. The effect of the mutation on DAPK catalytic activity and the finding of only localized changes in the DAPK structure provide experimental evidence implicating conformational selection in this domain with activity. This article is part of a Special Issue entitled: 11th European Symposium on Calcium
Towards an Aero-Propulso-Servo-Elasticity Analysis of a Commercial Supersonic Transport
This paper covers the development of an aero-propulso-servo-elastic (APSE) model using computational fluid dynamics (CFD) and linear structural deformations. The APSE model provides the integration of the following two previously developed nonlinear dynamic simulations: a variable cycle turbofan engine and an elastic supersonic commercial transport vehicle. The primary focus of this study is to provide a means to include relevant dynamics of a turbomachinery propulsion system into the aeroelastic studies conducted during a vehicle design, which have historically neglected propulsion effects. A high fidelity CFD tool is used here for the integration platform. The elastic vehicle neglecting the propulsion system serves as a comparison of traditional approaches to the APSE results. An overview of the methodology is presented for integrating the propulsion system and elastic vehicle. Static aeroelastic analysis comparisons between the traditional and developed APSE models for a wing tip detection indicate that the propulsion system impact on the vehicle elastic response could increase the detection by approximately ten percent
QED blue-sheet effects inside black holes
The interaction of the unboundedly blue-shifted photons of the cosmic
microwave background radiation with a physical object falling towards the inner
horizon of a Reissner-Nordstrom black hole is analyzed. To evaluate this
interaction we consider the QED effects up to the second order in the
perturbation expansion. We then extrapolate the QED effects up to a cutoff,
which we introduce at the Planckian level. (Our results are not sensitive to
the cutoff energy.) We find that the energy absorbed by an infalling observer
is finite, and for typical parameters would not lead to a catastrophic heating.
However, this interaction would almost certainly be fatal for a human being, or
other living organism of similar size. On the other hand, we find that smaller
objects may survive the interaction. Our results do not provide support to the
idea that the Cauchy horizon is to be regarded as the boundary of spacetime.Comment: 6 pages, LaTeX. To appear in Phys. Rev.
Relation of exaggerated cytokine responses of CF airway epithelial cells to PAO1 adherence
In many model systems, cystic fibrosis (CF) phenotype airway epithelial cells in culture respond to P. aeruginosa with greater interleukin (IL)-8 and IL-6 secretion than matched controls. In order to test whether this excess inflammatory response results from the reported increased adherence of P. aeruginosa to the CF cells, we compared the inflammatory response of matched pairs of CF and non CF airway epithelial cell lines to the binding of GFP-PAO1, a strain of pseudomonas labeled with green fluorescent protein. There was no clear relation between GFP-PAO1 binding and cytokine production in response to PAO1. Treatment with exogenous aGM1 resulted in greater GFP-PAO1 binding to the normal phenotype compared to CF phenotype cells, but cytokine production remained greater from the CF cell lines. When cells were treated with neuraminidase, PAO1 adherence was equalized between CF and nonCF phenotype cell lines, but IL-8 production in response to inflammatory stimuli was still greater in CF phenotype cells. The polarized cell lines 16HBEo-Sense (normal phenotype) and Antisense (CF phenotype) cells were used to test the effect of disrupting tight junctions, which allows access of PAO1 to basolateral binding sites in both cell lines. IL-8 production increased from CF, but not normal, cells. These data indicate that increased bacterial binding to CF phenotype cells cannot by itself account for excess cytokine production in CF airway epithelial cells, encourage investigation of alternative hypotheses, and signal caution for therapeutic strategies proposed for CF that include disruption of tight junctions in the face of pseudomonas infection
Data challenges for international health emergencies: lessons learned from ten international COVID-19 driver projects
The COVID-19 pandemic highlighted the importance of international data sharing and access to improve health outcomes for all. The International COVID-19 Data Alliance (ICODA) programme enabled 12 exemplar or driver projects to use existing health-related data to address major research questions relating to the pandemic, and developed data science approaches that helped each research team to overcome challenges, accelerate the data research cycle, and produce rapid insights and outputs. These approaches also sought to address inequity in data access and use, test approaches to ethical health data use, and make summary datasets and outputs accessible to a wider group of researchers. This Health Policy paper focuses on the challenges and lessons learned from ten of the ICODA driver projects, involving researchers from 19 countries and a range of health-related datasets. The ICODA programme reviewed the time taken for each project to complete stages of the health data research cycle and identified common challenges in areas such as data sharing agreements and data curation. Solutions included provision of standard data sharing templates, additional data curation expertise at an early stage, and a trusted research environment that facilitated data sharing across national boundaries and reduced risk. These approaches enabled the driver projects to rapidly produce research outputs, including publications, shared code, dashboards, and innovative resources, which can all be accessed and used by other research teams to address global health challenges
D-cycloserine augmentation of exposure-based cognitive behavior therapy for anxiety, obsessive-compulsive, and posttraumatic stress disorders: a systematic review and meta-analysis of individual participant data
Importance: Whether and under which conditions D-cycloserine (DCS) augments the effects of exposure-based cognitive behavior therapy for anxiety, obsessive-compulsive, and posttraumatic stress disorders is unclear. Objective: To clarify whether DCS is superior to placebo in augmenting the effects of cognitive behavior therapy for anxiety, obsessive-compulsive, and posttraumatic stress disorders and to evaluate whether antidepressants interact with DCS and the effect of potential moderating variables. Data Sources: PubMed, EMBASE, and PsycINFO were searched from inception to February 10, 2016. Reference lists of previous reviews and meta-analyses and reports of randomized clinical trials were also checked. Study Selection: Studies were eligible for inclusion if they were (1) double-blind randomized clinical trials of DCS as an augmentation strategy for exposure-based cognitive behavior therapy and (2) conducted in humans diagnosed as having specific phobia, social anxiety disorder, panic disorder with or without agoraphobia, obsessive-compulsive disorder, or posttraumatic stress disorder. Data Extraction and Synthesis: Raw data were obtained from the authors and quality controlled. Data were ranked to ensure a consistent metric across studies (score range, 0-100). We used a 3-level multilevel model nesting repeated measures of outcomes within participants, who were nested within studies. Results: Individual participant data were obtained for 21 of 22 eligible trials, representing 1047 of 1073 eligible participants. When controlling for antidepressant use, participants receiving DCS showed greater improvement from pretreatment to posttreatment (mean difference, -3.62; 95% CI, -0.81 to -6.43; P = .01; d = -0.25) but not from pretreatment to midtreatment (mean difference, -1.66; 95% CI, -4.92 to 1.60; P = .32; d = -0.14) or from pretreatment to follow-up (mean difference, -2.98, 95% CI, -5.99 to 0.03; P = .05; d = -0.19). Additional analyses showed that participants assigned to DCS were associated with lower symptom severity than those assigned to placebo at posttreatment and at follow-up. Antidepressants did not moderate the effects of DCS. None of the prespecified patient-level or study-level moderators was associated with outcomes. Conclusions and Relevance: D-cycloserine is associated with a small augmentation effect on exposure-based therapy. This effect is not moderated by the concurrent use of antidepressants. Further research is needed to identify patient and/or therapy characteristics associated with DCS response.2018-05-0
Elliptical Galaxies and Bulges of Disk Galaxies: Summary of Progress and Outstanding Issues
This is the summary chapter of a review book on galaxy bulges. Bulge
properties and formation histories are more varied than those of ellipticals. I
emphasize two advances: 1 - "Classical bulges" are observationally
indistinguishable from ellipticals, and like them, are thought to form by major
galaxy mergers. "Disky pseudobulges" are diskier and more actively star-forming
(except in S0s) than are ellipticals. Theys are products of the slow
("secular") evolution of galaxy disks: bars and other nonaxisymmetries move
disk gas toward the center, where it starbursts and builds relatively flat,
rapidly rotating components. This secular evolution is a new area of galaxy
evolution work that complements hierarchical clustering. 2 - Disks of
high-redshift galaxies are unstable to the formation of mass clumps that sink
to the center and merge - an alternative channel for the formation of classical
bulges. I review successes and unsolved problems in the formation of
bulges+ellipticals and their coevolution (or not) with supermassive black
holes. I present an observer's perspective on simulations of dark matter galaxy
formation including baryons. I review how our picture of the quenching of star
formation is becoming general and secure at redshifts z < 1. The biggest
challenge is to produce realistic bulges+ellipticals and disks that overlap
over a factor of 10**3 in mass but that differ from each other as observed over
that whole range. Second, how does hierarchical clustering make so many giant,
bulgeless galaxies in field but not cluster environments? I argue that we rely
too much on AGN and star-formation feedback to solve these challenges.Comment: 46 pages, 10 postscript figures, accepted for publication in Galactic
Bulges, ed. E. Laurikainen, R. F. Peletier, & D. A. Gadotti (New York:
Springer), in press (2015
An Open-Label Study of Aripiprazole in Children with a Bipolar Disorder
The purpose of this open-label study was to describe the effectiveness of aripiprazole (APZ) in the treatment of children with bipolar disorders suffering from manic symptomatology
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