4,209 research outputs found
Nonequilibrium stationary states of 3D self-gravitating systems
Three dimensional self-gravitating systems do not evolve to thermodynamic
equilibrium, but become trapped in nonequilibrium quasistationary states. In
this Letter we present a theory which allows us to a priori predict the
particle distribution in a final quasistationary state to which a
self-gravitating system will evolve from an initial condition which is
isotropic in particle velocities and satisfies a virial constraint 2K=-U, where
K is the total kinetic energy and U is the potential energy of the system
Foxj1a is expressed in ependymal precursors, controls central canal position and is activated in new ependymal cells during regeneration in zebrafish
© 2017 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are creditedZebrafish are able to regenerate the spinal cord and recover motor and sensory functions upon severe injury, through the activation of cells located at the ependymal canal. Here, we show that cells surrounding the ependymal canal in the adult zebrafish spinal cord express Foxj1a. We demonstrate that ependymal cells express Foxj1a from their birth in the embryonic neural tube and that Foxj1a activity is required for the final positioning of the ependymal canal. We also show that in response to spinal cord injury, Foxj1a ependymal cells actively proliferate and contribute to the restoration of the spinal cord structure. Finally, this study reveals that Foxj1a expression in the injured spinal cord is regulated by regulatory elements activated during regeneration. These data establish Foxj1a as a pan-ependymal marker in development, homeostasis and regeneration and may help identify the signals that enable this progenitor population to replace lost cells after spinal cord injury.This research was supported by FCT (Portugal) grants (PTDC/BIM-MED/1375/2012 and PTDC/BIM-MED/3295/2014) given to L.S. L.S. was supported by an IF contract from FCT (Portugal). A.R. was supported by a postdoctoral fellowship of the FCT (Portugal) (SFRH/BPD/100162/2014) and EMBO (605-2012)info:eu-repo/semantics/publishedVersio
Tropical Plant Responses to Climate Change
Editorialinfo:eu-repo/semantics/publishedVersio
Activation of adenosine A2A receptors induces TrkB translocation and increases BDNF-mediated phospho-TrkB localization in lipid rafts : implications for neuromodulation
Copyright © 2010 the authorsBrain-derived neurotrophic factor (BDNF) signaling is critical for neuronal development and transmission. Recruitment of TrkB receptors to lipid rafts has been hown to be necessary for the activation of specific signaling pathways and modulation of neurotransmitter release by BDNF. Since TrkB receptors are known to be modulated by adenosine A2A receptor activation, we hypothesized that activation of A2A receptors could influence TrkB receptor localization among different membrane microdomains. We found that adenosine A2A receptor agonists increased the levels of TrkB receptors in the lipid raft fraction of cortical membranes and potentiated BDNF-induced augmentation of phosphorylated TrkB levels in lipid rafts. Blockade of the clathrin-mediated endocytosis with monodansylcadaverine(100µM) did not modify the effects of theA2A receptor agonists but significantly impairedBDNFeffects on TrkB recruitment to lipid rafts.
The effect of A2A receptor activation in TrkB localization was mimicked by 5 µM forskolin, an adenylyl cyclase activator. Also, it was blocked by the PKA inhibitors Rp-cAMPs and PKI-(14 –22), and by the Src-family kinase inhibitor PP2. Moreover, removal of endogenous adenosine or disruption of lipid rafts reduced BDNF stimulatory effects on glutamate release from cortical synaptosomes.
Lipid raft integrity was also required for the effects of BDNF on hippocampal long-term potentiation at CA1 synapses. Our data
demonstrate, for the first time, a BDNF-independent recruitment of TrkB receptors to lipid rafts induced by activation of adenosine A2A receptors, with functional consequences for TrkB phosphorylation and BDNF-induced modulation of neurotransmitter
release and hippocampal plasticity.Supported by Fundacão para a Ciência e a Tecnologia (SFRH/BD/21374/2005 for N.A.L., SFRH/BD/21359/2005 for V.C.S., and SFRH/BPD/11528/2002 for D.B.P.) and by the European Union [European Cooperation in Science and Technology (COST) COST B30 concerted action, Neural Regeneration and Plasticity (NEREPLAS)]
Light with tunable non-Markovian phase imprint
We introduce a simple and flexible method to generate spatially non-Markovian
light with tunable coherence properties in one and two dimensions. The unusual
behavior of this light is demonstrated experimentally by probing the far field
and recording its diffraction pattern after a double slit: In both cases we
observe instead of a central intensity maximum a line or cross shaped dark
region, whose width and profile depend on the non-Markovian coherence
properties. Since these properties can be controlled and easily reproduced in
experiment, the presented approach lends itself to serve as a testbed to gain a
deeper understanding of non-Markovian processes
Funcionamiento familiar en una muestra portuguesa de adultos durante el COVID-19: ¿importa la esperanza?
The purpose of this study was to explore the relationships between sociodemographic, clinical, and psychological
variables and their contribution towards family functioning during the first wave of COVID-19 in Portugal. The COVID-19
pandemic was an overwhelming and stressful life event with social consequences that impacted family functioning and
contributed to multilevel disruptions. The study used a cross-sectional design and included 110 participants (94 women),
with a mean age of 35.71 (SD = 13.53). Participants answered self-report measures assessing family satisfaction, hope,
psychological well-being, risk perception, and family functioning. Hope (pathways subscale) played a moderating role
in the relationship between family satisfaction and family functioning. Family satisfaction and psychological well-being
partially mediated the relationship between hope and family functioning. Clinical relevance and implications for further
research are addressed. Intervention should focus on increasing psychological well-being and hope together with family
satisfaction in order to promote family functioning. For those individuals struggling with COVID-19 issues, mental health
interventions are paramount.Este estudio ha tenido como objetivo explorar la relación entre las variables sociodemográficas, clínicas y psicológicas y
el funcionamiento familiar en la primera oleada de COVID-19 en Portugal. La pandemia de COVID-19 fue una situación de
vida abrumadora y estresante con consecuencias sociales que afectaron en el funcionamiento familiar. El estudio utilizó un
diseño transversal e incluyó 110 participantes (94 mujeres), con una edad media de 35.71 años (SD = 13.53). Los participantes
respondieron a medidas que evaluaban la satisfacción familiar, la esperanza, el bienestar psicológico, la percepción del riesgo
y el funcionamiento familiar. La esperanza (subescala “caminos”) desempeñó un papel moderador en la relación entre la
satisfacción familiar y el funcionamiento familiar. La satisfacción familiar y el bienestar psicológico mediaron parcialmente
en la relación entre la esperanza y el funcionamiento familiar. Se abordan la importancia clínica y las implicaciones para
futuras investigaciones. La intervención deberá centrarse en aumentar el bienestar psicológico y la esperanza junto con la
satisfacción familiar para promover el funcionamiento familiar. Para los individuos que luchan con problemas de COVID-19
son primordiales las intervenciones de salud mental
A Comparative Study
This research was funded by EU funds through the FEDER European Regional Development Fund (project LISBOA-02-0145-FEDER-031311) project LA/P/0056/2020 of Institute of Molecular Sciences, and LA/P/0140/2020 of i4HB, project UID/EEA/00066/2020 from the Center of Technology and Systems, and from the Instituto Politécnico de Lisboa with IPL/2018/STREAM_ISEL and IPL/2020/AGE-SPReS_ISEL projects. APCR and AMF thank the Instituto Superior Técnico for the scientific employment contracts IST-ID/119/2018 and IST-ID/131/2018, respectively.
Publisher Copyright:
© 2022 by the authors. Licensee MDPI, Basel, Switzerland.Aiming to develop a nanoparticle-based optical biosensor using gold nanoparticles (AuNPs) synthesized using green methods and supported by carbon-based nanomaterials, we studied the role of carbon derivatives in promoting AuNPs localized surface plasmon resonance (LSPR), as well as their morphology, dispersion, and stability. Carbon derivatives are expected to work as immobi-lization platforms for AuNPs, improving their analytical performance. Gold nanoparticles (AuNPs) were prepared using an eco-friendly approach in a single step by reduction of HAuCl4·3H2O using phytochemicals (from tea) which act as both reducing and capping agents. UV–Vis spectroscopy, transmission electron microscopy (TEM), zeta potential (ζ-potential), and X-ray photoelectron spectroscopy (XPS) were used to characterize the AuNPs and nanocomposites. The addition of reduced graphene oxide (rGO) resulted in greater dispersion of AuNPs on the rGO surface compared with carbon-based nanomaterials used as a support. Differences in morphology due to the nature of the carbon support were observed and are discussed here. AuNPs/rGO seem to be the most promising candidates for the development of LSPR biosensors among the three composites we studied (AuNPs/G, AuNPs/GO, and AuNPs/rGO). Simulations based on the Mie scattering theory have been used to outline the effect of the phytochemicals on LSPR, showing that when the presence of the residuals is limited to the formation of a thin capping layer, the quality of the plasmonic resonance is not affected. A further discussion of the application framework is presented.publishersversionpublishe
A risk-based framework to manage single-use systems over lifecycle: Design, cleaning, operation, ongoing process verification
Using a formal risk management approach, SU systems (SUSs) and classical stainless steel-based systems (CSSs) are examined in detail. The risk assessment steps include: identification, analysis, mitigation and reevaluation/verification of risks over lifecycle. Adequate risk tools are used for each step. Failure modes specific of each type of system, are considered. The scientific background described in BPOG’s Guidelines on extractables (2014) and leachables (Jan.2017) for SUSs is built in, together with other authoritative sources for both types of systems. The risk quantitation, profiling and the holistic risk visualization for both technology platforms, allows companies with stainless steel only fermentation capacity and those with a mix of both technologies, to consider how to best evolve their capacity, when potential impacts on product quality and patient safety are taken into account. In addition to allowing the relative benchmarking of both technology platforms, comparisons over lifecycle of a specific platform are made possible by our approach, enabling companies to retain a complete picture of all their risk-based decisions and very detailed knowledge about their assets performance. The knowledge management component proposed is unique and supports several business processes and also decisions a company needs to justify before authorities. Our talk provides an insightful discussion of SUSs, using state-of-the-art risk-based and knowledge management tools, illustrated by examples on Design, Cleaning, Operation and Ongoing Process Verification, focusing on risks to quality and safety
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