3,484 research outputs found
Sex Differences in Arm Muscle Fatigability With Cognitive Demand in Older Adults
Background
Muscle fatigability can increase when a stressful, cognitively demanding task is imposed during a low-force fatiguing contraction with the arm muscles, especially in women. Whether this occurs among older adults (\u3e 60 years) is currently unknown.
Questions/purposes
We aimed to determine if higher cognitive demands, stratified by sex, increased fatigability in older adults (\u3e 60 years). Secondarily, we assessed if varying cognitive demand resulted in decreased steadiness and was explained by anxiety or cortisol levels.
Methods
Seventeen older women (70 ± 6 years) and 13 older men (71 ± 5 years) performed a sustained, isometric, fatiguing contraction at 20% of maximal voluntary contraction until task failure during three sessions: high cognitive demand (high CD = mental subtraction by 13); low cognitive demand (low CD = mental subtraction by 1); and control (no subtraction).
Results
Fatigability was greater when high and low CD were performed during the fatiguing contraction for the women but not for the men. In women, time to failure with high CD was 16 ± 8 minutes and with low CD was 17 ± 4 minutes, both of which were shorter than time to failure in control contractions (21 ± 7 minutes; high CD mean difference: 5 minutes [95% confidence interval {CI}, 0.78–9.89], p = 0.02; low CD mean difference: 4 minutes [95% CI, 0.57–7.31], p = 0.03). However, in men, no differences were detected in time to failure with cognitive demand (control: 13 ± 5 minutes; high CD mean difference: −0.09 minutes [95% CI, −2.8 to 2.7], p = 1.00; low CD mean difference: 0.75 minutes [95% CI, −1.1 to 2.6], p = 0.85). Steadiness decreased (force fluctuations increased) more during high CD than control. Elevated anxiety, mean arterial pressure, and salivary cortisol levels in both men and women did not explain the greater fatigability during high CD.
Conclusions
Older women but not men showed marked increases in fatigability when low or high CD was imposed during sustained static contractions with the elbow flexor muscles and contrasts with previous findings for the lower limb. Steadiness decreased in both sexes when high CD was imposed.
Clinical Relevance
Older women are susceptible to greater fatigability of the upper limb with heightened mental activity during sustained postural contractions, which are the foundation of many work-related tasks
Implementation of the new multichannel X-mode edge density profile reflectometer for the ICRF antenna on ASDEX Upgrade
A new multichannel frequency modulated continuous-wave reflectometry diagnostic has been successfully installed and commissioned on ASDEX Upgrade to measure the plasma edge electron density profile evolution in front of the Ion Cyclotron Range of Frequencies (ICRF) antenna. The design of the new three-strap ICRF antenna integrates ten pairs (sending and receiving) of microwave reflectometry antennas. The multichannel reflectometer can use three of these to measure the edge electron density profiles up to 2 x 10(19) m(-3), at different poloidal locations, allowing the direct study of the local plasma layers in front of the ICRF antenna. ICRF power coupling, operational effects, and poloidal variations of the plasma density profile can be consistently studied for the first time. In this work the diagnostic hardware architecture is described and the obtained density profile measurements were used to track outer radial plasma position and plasma shape
French Version of Taste (Test for the Ability and Evaluation)
peer reviewedS'inspirant des champs traditionnels de recherche ("test anxiety" et " need of achievement "), des travaux sur l'attribution causale de Weiner et de ceux de "Self efficacy" de Bandura, Eric Depreeuw, dans le cadre de la peur de l'échec, s'est aussi penché sur l'œuvre de Heckhausen qui tente d'associer les modèles expérimentaux à la complexité de la réalité clinique. Le questionnaire (78 items) qu'il a élaboré (VaSEV) évalue 4 facteurs : anxiété, confiance en soi, procrastination et valeur attribuée à la performance. C'est ce questionnaire que nous avons adapté en français à partir de sa composition première (121 items). L 'étude statistique menée auprès d'une population d'étudiants de première année de l'Université de Liège (n = 617) permet de confirmer l 'étude initiale, en optant toutefois pour une solution ajoutant un cinquième facteur particulièrement solide (alpha de Cronbach = 0,84) et correspondant à la dévalorisation. Le questionnaire a été simplifié (50 items) en ne gardant, par facteur, que les 10 items les plus spécifiques de chacun d'entre eux. La consistance interne et la stabilité temporelle sont tout à fait satisfaisantes. Appliqué à l'échantillon étudié, le test s'avère performant et a permis de différencier la population concernée de manière significative selon le sexe et l'expérience de l'échec (tableaux I et II)
Phosphorylation of Janus kinase 1 (JAK1) by AMP-activated protein kinase (AMPK) links energy sensing to anti-inflammatory signaling
Adenosine 5′-monophosphate-activated protein kinase (AMPK) is a pivotal regulator of metabolism at cellular and organismal levels. AMPK also suppresses inflammation. We found that pharmacological activation of AMPK rapidly inhibited the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway in various cells. In vitro kinase assays revealed that AMPK directly phosphorylated two residues (Ser515 and Ser518) within the Src homology 2 domain of JAK1. Activation of AMPK enhanced the interaction between JAK1 and 14-3-3 proteins in cultured vascular endothelial cells and fibroblasts, an effect that required the presence of Ser515 and Ser518 and was abolished in cells lacking AMPK catalytic subunits. Mutation of Ser515 and Ser518 abolished AMPK-mediated inhibition of JAK-STAT signaling stimulated by either the sIL-6Ra/IL-6 complex or the expression of a constitutively active V658F-mutant JAK1 in human fibrosarcoma cells. Clinically used AMPK activators metformin and salicylate enhanced the inhibitory phosphorylation of endogenous JAK1 and inhibited STAT3 phosphorylation in primary vascular endothelial cells. Therefore, our findings reveal a mechanism by which JAK1 function and inflammatory signaling may be suppressed in response to metabolic stress and provide a mechanistic rationale for the investigation of AMPK activators in a range of diseases associated with enhanced activation of the JAK-STAT pathway. 2016</p
Optimizing Nervous System-Specific Gene Targeting with Cre Driver Lines: Prevalence of Germline Recombination and Influencing Factors.
The Cre-loxP system is invaluable for spatial and temporal control of gene knockout, knockin, and reporter expression in the mouse nervous system. However, we report varying probabilities of unexpected germline recombination in distinct Cre driver lines designed for nervous system-specific recombination. Selective maternal or paternal germline recombination is showcased with sample Cre lines. Collated data reveal germline recombination in over half of 64 commonly used Cre driver lines, in most cases with a parental sex bias related to Cre expression in sperm or oocytes. Slight differences among Cre driver lines utilizing common transcriptional control elements affect germline recombination rates. Specific target loci demonstrated differential recombination; thus, reporters are not reliable proxies for another locus of interest. Similar principles apply to other recombinase systems and other genetically targeted organisms. We hereby draw attention to the prevalence of germline recombination and provide guidelines to inform future research for the neuroscience and broader molecular genetics communities
Resolving the ancestry of Austronesian-speaking populations
There are two very different interpretations of the prehistory of Island Southeast Asia (ISEA), with genetic evidence invoked in support of both. The “out-of-Taiwan” model proposes a major Late Holocene expansion of Neolithic Austronesian speakers from Taiwan. An alternative, proposing that Late Glacial/postglacial sea-level rises triggered largely autochthonous dispersals, accounts for some otherwise enigmatic genetic patterns, but fails to explain the Austronesian language dispersal. Combining mitochondrial DNA (mtDNA), Y-chromosome and genome-wide data, we performed the most comprehensive analysis of the region to date, obtaining highly consistent results across all three systems and allowing us to reconcile the models. We infer a primarily common ancestry for Taiwan/ISEA populations established before the Neolithic, but also detected clear signals of two minor Late Holocene migrations, probably representing Neolithic input from both Mainland Southeast Asia and South China, via Taiwan. This latter may therefore have mediated the Austronesian language dispersal, implying small-scale migration and language shift rather than large-scale expansion
Polarised Quark Distributions in the Nucleon from Semi-Inclusive Spin Asymmetries
We present a measurement of semi-inclusive spin asymmetries for positively
and negatively charged hadrons from deep inelastic scattering of polarised
muons on polarised protons and deuterons in the range 1
GeV. Compared to our previous publication on this subject, with the new
data the statistical errors have been reduced by nearly a factor of two.
From these asymmetries and our inclusive spin asymmetries we determine the
polarised quark distributions of valence quarks and non-strange sea quarks at
=10 GeV. The polarised valence quark distribution, , is positive and the polarisation increases with . The polarised
valence quark distribution, , is negative and the non-strange
sea distribution, , is consistent with zero over the measured
range of . We find for the first moments , and
, where we assumed
. We also determine for the first time the
second moments of the valence distributions .Comment: 17 page
JOGO EDUCATIVO PARA A DISCIPLINA DE GEOGRAFIA
This paper discusses the project of an educational game that was developed for the discipline of geography. Currently the educational games are increasingly being used inside schools in order to bring the play to the learning environment, making the lessons more enjoyable and aiding the process of teaching and learning. The idea to develop this game of Geography is to encourage children to learn more about this discipline, through games like puzzle games, memory games, questions and answers among others, that address various issues in Brazil and the world
JOGO EDUCATIVO PARA A DISCIPLINA DE GEOGRAFIA
Este artigo discorre sobre o projeto de um jogo educativo que foi desenvolvido para a disciplina de geografia. Atualmente os jogos educacionais estão sendo cada vez mais usados dentro das escolas com o objetivo de levar o lúdico para o ambiente de aprendizado, tornando as aulas mais agradáveis e auxiliando o processo de ensino aprendizagem. A idéia ao se desenvolver este jogo de Geografia é incentivar as crianças a aprenderem mais sobre esta disciplina, através de jogos como quebra-cabeça, jogos de memória, jogos de perguntas e respostas entre outros, que abordam vários assuntos do Brasil e do mundo
EGFRvIII deletion mutations in pediatric high-grade glioma and response to targeted therapy in pediatric glioma cell lines
Purpose: The epidermal growth factor receptor (EGFR) is amplified and overexpressed
in adult glioblastoma, with response to targeted inhibition dependent on the underlying
biology of the disease. EGFR has thus far been considered to play a less important role
in pediatric glioma, although extensive data are lacking. We have sought to clarify the
role of EGFR in pediatric high-grade glioma (HGG).
Experimental Design: We retrospectively studied a total of 90 archival pediatric HGG
specimens for EGFR protein overexpression, gene amplification, and mutation and assessed the in vitro sensitivity of pediatric glioma cell line models to the small-molecule
EGFR inhibitor erlotinib.
Results: Amplification was detected in 11% of cases, with corresponding overexpression of the receptor. No kinase or extracellular domain mutations were observed; however, 6 of 35 (17%) cases harbored the EGFRvIII deletion, including two anaplastic
oligodendrogliomas and a gliosarcoma overexpressing EGFRvIII in the absence of gene
amplification and coexpressing platelet-derived growth factor receptor α. Pediatric glioblastoma cells transduced with wild-type or deletion mutant EGFRvIII were not rendered
more sensitive to erlotinib despite expressing wild-type PTEN. Phosphorylated receptor
tyrosine kinase profiling showed a specific activation of platelet-derived growth factor
receptor α/β in EGFRvIII-transduced pediatric glioblastoma cells, and targeted coinhibition with erlotinib and imatinib leads to enhanced efficacy in this model.
Conclusions: These data identify an elevated frequency of EGFR gene amplification and
EGFRvIII mutation in pediatric HGG than previously recognized and show the likely
necessity of targeting multiple genetic alterations in the tumors of these children.Cancer Research UK grants C1178/A10294, C309/A2187, and
C309/A8274; Oak Foundation (L. Marshall); La Fondation de France (N. Gaspar);
and Breakthrough Breast Cancer (J.S. Reis-Filho). We acknowledge NHS funding to the National Institute for Health Research Biomedical Research Centre
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