907 research outputs found

    Field-Aligned Current During an Interval of BY-Dominated Interplanetary-Field; Modeled-to-Observed Comparisons

    Get PDF
    We model an interval of remarkable interplanetary magnetic field (IMF), for which we have a comprehensive set of observational data. This interval is associated with the arrival of an interplanetary coronal mass ejection. The solar wind densities at the time are particularly high and the IMF is primarily northward over many hours. This results in strong auroral emissions within the polar cap in a cusp spot, which we associate with lobe reconnection at the high-latitude magnetopause. We also observe areas of upwards field-aligned current (FAC) within the summer Northern Hemisphere polar cap that exhibit large current magnitudes. The model can reproduce the spatial distribution of the FACs well, even under changing conditions in the incoming IMF. Discrepancies exist between the modeled and observed current magnitudes. Notably, the winter Southern Hemisphere exhibits much lower current magnitudes overall. We also model a sharp transition of the location of magnetopause reconnection at the beginning of the interval, before the IMF remained northward for many hours. The reconnection location changed rapidly from a subsolar location at the low-latitude magnetopause under southward IMF conditions, to a high-latitude lobe reconnection location when the field is northward. This occurs during a fast rotation of the IMF at the shock front of a magnetic cloud

    The life and miracles of kinetochores

    Get PDF
    Kinetochores are large protein assemblies built on chromosomal loci named centromeres. The main functions of kinetochores can be grouped under four modules. The first module, in the inner kinetochore, contributes a sturdy interface with centromeric chromatin. The second module, the outer kinetochore, contributes a microtubule-binding interface. The third module, the spindle assembly checkpoint, is a feedback control mechanism that monitors the state of kinetochore–microtubule attachment to control the progression of the cell cycle. The fourth module discerns correct from improper attachments, preventing the stabilization of the latter and allowing the selective stabilization of the former. In this review, we discuss how the molecular organization of the four modules allows a dynamic integration of kinetochore–microtubule attachment with the prevention of chromosome segregation errors and cell-cycle progression

    Decision for reconstructive interventions of the upper limb in individuals with tetraplegia: the effect of treatment characteristics

    Get PDF
    Objective: To determine the effect of treatment characteristics on the\ud decision for reconstructive interventions for the upper extremities (UE) in\ud subjects with tetraplegia. - \ud Setting: Seven specialized spinal cord injury centres in the Netherlands. - \ud Method: Treatment characteristics for UE reconstructive interventions were\ud determined. Conjoint analysis (CA) was used to determine the contribution\ud and the relative importance of the treatment characteristics on the decision\ud for therapy. Therefore, a number of different treatment scenarios using these\ud characteristics were established. Different pairs of scenarios were presented\ud to subjects who were asked to choose the preferred scenario of each set. - \ud Results: forty nine subjects with tetraplegia with a stable C5, C6 or C7\ud lesion were selected. All treatment characteristics significantly influenced\ud the choice for treatment. Relative importance of treatment characteristics\ud were: intervention type (surgery or surgery with FES implant) 13%, number\ud of operations 15%, in patient rehabilitation period 22%, ambulant\ud rehabilitation period 9%, complication rate 15%, improvement of elbow\ud function 10%, improvement of hand function 15%. In deciding for therapy\ud 40% of the subjects focused on one characteristic. - \ud Conclusion: CA is applicable in Spinal Cord Injury medicine to study the\ud effect of health outcomes and non-health outcomes on the decision for\ud treatment. Non-health outcomes which relate to the intensity of treatment\ud are equally important or even more important than functional outcome in the\ud decision for reconstructive UE surgery in subjects with tetraplegia

    STAT3 regulates the onset of oxidant-induced senescence in lung fibroblasts

    Get PDF
    Copyright © 2019 by the American Thoracic Society. Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease of unknown cause with a median survival of only 3 years. Other investigators and we have shown that fibroblasts derived from IPF lungs display characteristics of senescent cells, and that dysregulated activation of the transcription factor signal transducer and activator of transcription 3 (STAT3) correlates with IPF progression. The question of whether STAT3 activation is involved in fibroblast senescence remains unanswered. We hypothesized that inhibiting STAT3 activation after oxidantinduced senescence would attenuate characteristics of the senescent phenotype. We aimed to characterize a model of oxidant-induced senescence in human lung fibroblasts and to determine the effect of inhibiting STAT3 activity on the development of senescence. Exposing human lung fibroblasts to 150 ÎŒM hydrogen peroxide (H2O2) resulted in increased senescence-associated ÎČ-galactosidase content and expression of p21 and IL-6, all of which are features of senescence. The shift into senescence was accompanied by an increase of STAT3 translocation to the nucleus and mitochondria. Additionally, Seahorse analysis provided evidence of increased mitochondrial respiration characterized by increased basal respiration, proton leak, and an associated increase in superoxide (O2-) production in senescent fibroblasts. Targeting STAT3 activity using the small-molecule inhibitor STA-21 attenuated IL-6 production, reduced p21 levels, decreased senescence-associated b-galactosidase accumulation, and restored normalmitochondrial function. The results of this study illustrate that stress-induced senescence in lung fibroblasts involves the activation of STAT3, which can be pharmacologically modulated

    Survey of the needs of patients with spinal cord injury: impact and priority for improvement in hand function in tetraplegics\ud

    Get PDF
    Objective: To investigate the impact of upper extremity deficit in subjects with tetraplegia.\ud \ud Setting: The United Kingdom and The Netherlands.\ud \ud Study design: Survey among the members of the Dutch and UK Spinal Cord Injury (SCI) Associations.\ud \ud Main outcome parameter: Indication of expected improvement in quality of life (QOL) on a 5-point scale in relation to improvement in hand function and seven other SCI-related impairments.\ud \ud Results: In all, 565 subjects with tetraplegia returned the questionnaire (overall response of 42%). Results in the Dutch and the UK group were comparable. A total of 77% of the tetraplegics expected an important or very important improvement in QOL if their hand function improved. This is comparable to their expectations with regard to improvement in bladder and bowel function. All other items were scored lower.\ud \ud Conclusion: This is the first study in which the impact of upper extremity impairment has been assessed in a large sample of tetraplegic subjects and compared to other SCI-related impairments that have a major impact on the life of subjects with SCI. The present study indicates a high impact as well as a high priority for improvement in hand function in tetraplegics.\ud \u

    D-cycloserine-augmented one-session treatment of specific phobias in children and adolescents.

    Full text link
    BACKGROUND: D-Cycloserine has potential to enhance exposure therapy outcomes. The current study presents a preliminary randomized, placebo-controlled double-blind pilot trial of DCS-augmented one-session treatment (OST) for youth (7-14 years) with specific phobia. A secondary aim of this pilot study was to explore the effects of youth age and within-session fear reduction as potential moderators of DCS outcomes in order to generate hypotheses for a larger trial. It was hypothesized that DCS would be associated with greater improvements than placebo, that children (7-10 years) would have greater benefits than adolescents (11-14 years), and that DCS effects would be stronger for participants with the greater within-session fear reduction during the OST. METHODS: Thirty-five children and adolescents were randomized to either OST combined with DCS (n = 17), or OST combined with placebo (PBO; n = 18) and assessed at 1 week, 1 month, and 3 month following treatment. RESULTS: There were no significant pre- to post-treatment or follow-up benefits of DCS relative to placebo. Secondary analyses of age indicated that relative to PBO, DCS was associated with greater improvements for children (but not adolescents) on measures of severity at 1-month follow-up. Children in the DCS condition also showed significantly greater improvement to 1 month on global functioning relative to other groups. Conversely, adolescents had significant post-treatment benefits in the PBO condition on symptom severity measures relative to DCS, and adolescents in the DCS condition had significantly poorer functioning at 3 months relative to all other groups. Finally, there was a trend for within-session fear reduction to be associated with moderating effects of DCS, whereby greater reduction in fear was associated with greater functioning at one-month follow-up for children who received DCS, relative to PBO. LIMITATIONS: The study sample was small and therefore conclusions are tentative and require replication. CONCLUSIONS: Age and within-session fear reduction may be important moderators of DCS-augmented one-session exposure therapy, which requires testing in a fully powered randomized controlled trial

    Ventilatory drive and the apnea-hypopnea index in six-to-twelve year old children

    Get PDF
    BACKGROUND: We tested the hypothesis that ventilatory drive in hypoxia and hypercapnia is inversely correlated with the number of hypopneas and obstructive apneas per hour of sleep (obstructive apnea hypopnea index, OAHI) in children. METHODS: Fifty children, 6 to 12 years of age were studied. Participants had an in-home unattended polysomnogram to compute the OAHI. We subsequently estimated ventilatory drive in normoxia, at two levels of isocapnic hypoxia, and at three levels of hyperoxic hypercapnia in each subject. Experiments were done during wakefulness, and the mouth occlusion pressure measured 0.1 seconds after inspiratory onset (P(0.1)) was measured in all conditions. The slope of the relation between P(0.1 )and the partial pressure of end-tidal O(2 )or CO(2 )(P(ET)O(2 )and P(ET)CO(2)) served as the index of hypoxic or hypercapnic ventilatory drive. RESULTS: Hypoxic ventilatory drive correlated inversely with OAHI (r = -0.31, P = 0.041), but the hypercapnic ventilatory drive did not (r = -0.19, P = 0.27). We also found that the resting P(ET)CO(2 )was significantly and positively correlated with the OAHI, suggesting that high OAHI values were associated with resting CO(2 )retention. CONCLUSIONS: In awake children the OAHI correlates inversely with the hypoxic ventilatory drive and positively with the resting P(ET)CO(2). Whether or not diminished hypoxic drive or resting CO(2 )retention while awake can explain the severity of sleep-disordered breathing in this population is uncertain, but a reduced hypoxic ventilatory drive and resting CO(2 )retention are associated with sleep-disordered breathing in 6–12 year old children

    MPHASYS: a mouse phenotype analysis system

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Systematic, high-throughput studies of mouse phenotypes have been hampered by the inability to analyze individual animal data from a multitude of sources in an integrated manner. Studies generally make comparisons at the level of genotype or treatment thereby excluding associations that may be subtle or involve compound phenotypes. Additionally, the lack of integrated, standardized ontologies and methodologies for data exchange has inhibited scientific collaboration and discovery.</p> <p>Results</p> <p>Here we introduce a Mouse Phenotype Analysis System (MPHASYS), a platform for integrating data generated by studies of mouse models of human biology and disease such as aging and cancer. This computational platform is designed to provide a standardized methodology for working with animal data; a framework for data entry, analysis and sharing; and ontologies and methodologies for ensuring accurate data capture. We describe the tools that currently comprise MPHASYS, primarily ones related to mouse pathology, and outline its use in a study of individual animal-specific patterns of multiple pathology in mice harboring a specific germline mutation in the DNA repair and transcription-specific gene Xpd.</p> <p>Conclusion</p> <p>MPHASYS is a system for analyzing multiple data types from individual animals. It provides a framework for developing data analysis applications, and tools for collecting and distributing high-quality data. The software is platform independent and freely available under an open-source license <abbrgrp><abbr bid="B1">1</abbr></abbrgrp>.</p

    Physiological Properties of Cholinergic and Non-Cholinergic Magnocellular Neurons in Acute Slices from Adult Mouse Nucleus Basalis

    Get PDF
    The basal forebrain is a series of nuclei that provides cholinergic input to much of the forebrain. The most posterior of these nuclei, nucleus basalis, provides cholinergic drive to neocortex and is involved in arousal and attention. The physiological properties of neurons in anterior basal forebrain nuclei, including medial septum, the diagonal band of Broca and substantia innominata, have been described previously. In contrast the physiological properties of neurons in nucleus basalis, the most posterior nucleus of the basal forebrain, are unknown.Here we investigate the physiological properties of neurons in adult mouse nucleus basalis. We obtained cell-attached and whole-cell recordings from magnocellular neurons in slices from P42-54 mice and compared cholinergic and non-cholinergic neurons, distinguished retrospectively by anti-choline acetyltransferase immunocytochemistry. The majority (70-80%) of cholinergic and non-cholinergic neurons were silent at rest. Spontaneously active cholinergic and non-cholinergic neurons exhibited irregular spiking at 3 Hz and at 0.3 to 13.4 Hz, respectively. Cholinergic neurons had smaller, broader action potentials than non-cholinergic neurons (amplitudes 64+/-3.4 and 75+/-2 mV; half widths 0.52+/-0.04 and 0.33+/-0.02 ms). Cholinergic neurons displayed a more pronounced slow after-hyperpolarization than non-cholinergic neurons (13.3+/-2.2 and 3.6+/-0.5 mV) and were unable to spike at high frequencies during tonic current injection (maximum frequencies of approximately 20 Hz and >120 Hz).Our results indicate that neurons in nucleus basalis share similar physiological properties with neurons in anterior regions of the basal forebrain. Furthermore, cholinergic and non-cholinergic neurons in nucleus basalis can be distinguished by their responses to injected current. To our knowledge, this is the first description of the physiological properties of cholinergic and non-cholinergic neurons in the posterior aspects of the basal forebrain complex and the first study of basal forebrain neurons from the mouse

    Prime movers : mechanochemistry of mitotic kinesins

    Get PDF
    Mitotic spindles are self-organizing protein machines that harness teams of multiple force generators to drive chromosome segregation. Kinesins are key members of these force-generating teams. Different kinesins walk directionally along dynamic microtubules, anchor, crosslink, align and sort microtubules into polarized bundles, and influence microtubule dynamics by interacting with microtubule tips. The mechanochemical mechanisms of these kinesins are specialized to enable each type to make a specific contribution to spindle self-organization and chromosome segregation
    • 

    corecore