309 research outputs found

    Early Preplasma Cells Define a Tolerance Checkpoint for Autoreactive B Cells

    Get PDF
    Ab-secreting plasma cells (PCs) are the effectors of humoral immunity. In this study, we describe regulation of autoreactive B cells specific for the ribonucleoprotein Smith (Sm) at an early pre-PC stage. These cells are defined by the expression of the PC marker CD138 and normal levels of CD19 and B220. They are present at a high frequency in normal mouse spleen and bone marrow, are Ag dependent, and are located predominantly along the T cell-B cell border and near bridging channels. Anti-Sm pre-PCs also occur at a high frequency in nonautoimmune mice and show additional phenotypic characteristics of PC differentiation. However, while some of these pre-PCs are Ab-secreting cells, those specific for Sm are not, indicating regulation. Consistent with this, anti-Sm pre-PCs have a higher turnover rate and higher frequency of cell death than those that do not bind Sm. Regulation of anti-Sm pre-PCs occurs upstream of the transcriptional repressor, B lymphocyte-induced maturation protein-1, expression. Regulation at this stage is overcome in autoimmune MRL/lpr mice and is accompanied by an altered B lymphocyte stimulator receptor profile. These data reveal a new B cell tolerance checkpoint that is overcome in autoimmunity

    Independent prognostic value of echocardiography and N-terminal pro–B-type natriuretic peptide in patients with heart failure

    Get PDF
    Echocardiographic indices of cardiac structure and function and natriuretic peptide levels are strong predictors of mortality in patients with heart failure. Whether cardiac ultrasound and natriuretic peptides provide independent prognostic information is uncertain

    The Science of Failure - Systems Health Monitoring for Satellite Applications

    Get PDF
    Presentation/lecture on systems health monitoring (diagnostics, prognostics, decision-making) with applications to satellite components and systems

    Transforming Last-Mile Logistics: Opportunities for more Sustainable Deliveries

    Get PDF
    Road congestion, air pollution and sustainability are increasingly important in major cities. We look to understand how last-mile deliveries in the parcel sector are impacting our roads. Using formative field work and quantitative analysis of consignment manifests and location data, we identify how the effectiveness of life-style couriers is contributing to both environmental and non-environmental externalities. This paper presents an analysis of delivery performances and practices in last-mile logistics in central London, quantifying the impacts differing levels of experience have on overall round efficiency. We identify eleven key opportunities for technological support for last-mile parcel deliveries that could contribute to both driver eectiveness and sustainability. We finish by examining how HCI can lead to improved environmental and social justice by re-considering and realizing future collaborative visions in last-mile logistics

    Light Curves and Colors of the Ejecta from Dimorphos after the DART Impact

    Full text link
    On 26 September 2022 the Double Asteroid Redirection Test (DART) spacecraft impacted Dimorphos, a satellite of the asteroid 65803 Didymos. Because it is a binary system, it is possible to determine how much the orbit of the satellite changed, as part of a test of what is necessary to deflect an asteroid that might threaten Earth with an impact. In nominal cases, pre-impact predictions of the orbital period reduction ranged from ~8.8 - 17.2 minutes. Here we report optical observations of Dimorphos before, during and after the impact, from a network of citizen science telescopes across the world. We find a maximum brightening of 2.29 ±\pm 0.14 mag upon impact. Didymos fades back to its pre-impact brightness over the course of 23.7 ±\pm 0.7 days. We estimate lower limits on the mass contained in the ejecta, which was 0.3 - 0.5% Dimorphos' mass depending on the dust size. We also observe a reddening of the ejecta upon impact.Comment: Accepted by Natur

    Falls, Depression and Antidepressants in Later Life: A Large Primary Care Appraisal

    Get PDF
    BACKGROUND: Depression and falls are common and co-exist for older people. Safe management of each of these conditions is important to quality of life. METHODS: A cross-sectional survey was used to examine medication use associated with injurious and non-injurious falls in 21,900 community-dwelling adults, aged 60 years or over from 383 Australian general practices recruited for the DEPS-GP Project. Falls and injury from falls, medication use, depressive symptoms (Primary Health Questionnaire (PHQ-9)), clinical morbidity, suicidal ideation and intent, health status (SF-12 Health Survey), demographic and lifestyle information was reported in a standardised survey. FINDINGS: Respondents were 71.8 years (sd 7.7) of age and 58.4% were women. 24% 11% and 8% reported falls, fall related injury, and sought medical attention respectively. Antidepressant use (odds ratio, OR: 1.46; 95% confidence interval, 95%CI: 1.25, 1.70), questionable depression (5-14 on PHQ OR: 1.32, 95%CI: 1.13, 1.53) and clinically significant symptoms of depression (15 or more on PHQ OR: 1.70, 95%CI: 1.14, 1.50) were independently associated with multiple falls. SSRI use was associated with the highest risk of multiple falls (OR: 1.66, 95%CI: 1.36, 2.02) amongst all psychotropic medications. Similar associations were observed for injurious falls. Over 60% of those with four accumulated risk factors had multiple falls in the previous year (OR: 3.40, 95%CI: 1.79, 6.45); adjusted for other demographic and health factors. INTERPRETATION: Antidepressant use (particularly SSRIs) was strongly associated with falls regardless of presence of depressive symptoms. Strategies to prevent falls should become a routine part of the management of older people with depression

    Cytokine-associated neutrophil extracellular traps and antinuclear antibodies in Plasmodium falciparum infected children under six years of age

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>In <it>Plasmodium falciparum</it>-infected children, the relationships between blood cell histopathology, blood plasma components, development of immunocompetence and disease severity remain poorly understood. Blood from Nigerian children with uncomplicated malaria was analysed to gain insight into these relationships. This investigation presents evidence for circulating neutrophil extracellular traps (NETs) and antinuclear IgG antibodies (ANA). The presence of NETs and ANA to double-stranded DNA along with the cytokine profiles found suggests autoimmune mechanisms that could produce pathogenesis in children, but immunoprotection in adults.</p> <p>Methods</p> <p>Peripheral blood smear slides and blood samples obtained from 21 Nigerian children under six years of age, presenting with uncomplicated malaria before and seven days after initiation of sulphadoxine-pyrimethamine (SP) treatment were analysed. The slides were stained with Giemsa and with DAPI. Levels of the pro-inflammatory cytokines IFN-γ, IL-2, TNF, CRP, and IL-6, select anti-inflammatory cytokines TGF-β and IL-10, and ANA were determined by immunoassay.</p> <p>Results</p> <p>The children exhibited circulating NETs with adherent parasites and erythrocytes, elevated ANA levels, a Th2 dominated cytokine profile, and left-shifted leukocyte differential counts. Nonspecific ANA levels were significant in 86% of the children pretreatment and in 100% of the children seven days after SP treatment, but in only 33% of age-matched control samples collected during the season of low parasite transmission. Levels of ANA specific for dsDNA were significant in 81% of the children both pre-treatment and post treatment.</p> <p>Conclusion</p> <p>The results of this investigation suggest that NET formation and ANA to dsDNA may induce pathology in falciparum-infected children, but activate a protective mechanism against falciparum malaria in adults. The significance of in vivo circulating chromatin in NETs and dsDNA ANA as a causative factor in the hyporesponsiveness of CpG oligonucleotide-based malaria vaccines is discussed.</p

    The First Molecular Phylogeny of Strepsiptera (Insecta) Reveals an Early Burst of Molecular Evolution Correlated with the Transition to Endoparasitism

    Get PDF
    A comprehensive model of evolution requires an understanding of the relationship between selection at the molecular and phenotypic level. We investigate this in Strepsiptera, an order of endoparasitic insects whose evolutionary biology is poorly studied. We present the first molecular phylogeny of Strepsiptera, and use this as a framework to investigate the association between parasitism and molecular evolution. We find evidence of a significant burst in the rate of molecular evolution in the early history of Strepsiptera. The evolution of morphological traits linked to parasitism is significantly correlated with the pattern in molecular rate. The correlated burst in genotypic-phenotypic evolution precedes the main phase of strepsipteran diversification, which is characterised by the return to a low and even molecular rate, and a period of relative morphological stability. These findings suggest that the transition to endoparasitism led to relaxation of selective constraint in the strepsipteran genome. Our results indicate that a parasitic lifestyle can affect the rate of molecular evolution, although other causal life-history traits correlated with parasitism may also play an important role
    corecore