1,301 research outputs found

    Sensor-based Particulate Measurement (Some Tall Tales from the Trenches)

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    Current evidence indicates that a relatively small number of vehicles are responsible for the majority of excess in-use emissions, e.g. about 10% of the Diesel Particulate Filter (DPF) equipped vehicles are believed to contribute about 70% of excess particulate matter (PM) emissions. But conventional I/M measurements (snap-acceleration opacity) and other similar ‘stop-and-test’ procedures are not sensitive enough to measure the difference between a properly functioning and a moderately malfunctioning DPF system, and can even be cross-sensitive to the by-products of some modern emission control systems, e.g. NO2 from Selective Catalytic Reduction. As a result, one of the key elements of a more effective next-generation emissions ‘stop-and-test’ procedure for modern vehicles would be a new ‘SMOG Check’ system. Here, using provisional data for several recent and on-going studies, we propose a sensor-array strategy based on the 3DATx parSYNC as an alternative to simply replacing one metric (opacity) with another. We present data on the effectiveness of this approach, and describe options to address cross-sensitivity. We also consider the analytical compromises required to build an instrument suitable for use in a commercial garage at a price-point that will make it viable, as well as the extended diagnostic capabilities of a multi-dimensional description of vehicle particulate emissions

    Immune dysregulation in myelodysplastic syndrome

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    Myelodysplastic syndrome (MDS) represents one of the most challenging health-related problems in the elderly. Characterized by dysplastic morphology in the bone marrow in association with ineffective hematopoiesis, pathophysiological causes of this disease are diverse including genetic abnormalities within myeloid progenitors, altered epigenetics, and changes in the bone marrow microenvironment. The concept that T-cell mediated autoimmunity contributes to bone marrow failure has been widely accepted due to hematologic improvement after immunosuppressive therapy (IST) in a subset of patients. Currently, IST for MDS primarily involves anti-thymocyte globulin (ATG)-based regimens in which responsiveness is strongly associated with younger (under 60 years) age at disease onset. In such cases, progressive cytopenia may occur as a consequence of expanded self-reactive CD8+ cytotoxic T lymphocytes (CTLs) that suppress hematopoietic progenitors. Although most hematologists agree that IST can offer durable hematologic remission in younger patients with MDS, an international clinical study and a better understanding of the molecular mechanisms contributing to the expansion of self-reactive CTLs is crucial. In this review, data accumulated in the US, Europe, and Asia will be summarized to provide insight and direction for a multi-center international trial

    Illuminating the Lived Experiences of Research with Indigenous Communities

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    The historical exploitation experienced by indigenous people in the United States has left a number of negative legacies, including dis- trust toward research. This distrust poses a barrier to progress made through culturally sensitive research. Given the complex history of research with indigenous groups, the purpose of this descriptive phenomenological study was to illuminate the lived experiences of both indigenous and non-indigenous researchers conducting cul- turally competent research with indigenous people. Interviews from 13 social science research experts revealed 6 underlying themes about their research with indigenous people, including respect and commitment, mutual trust, affirmation, harmony among multiple worldviews, responsibility, and spiritual/personal growth

    “It will always continue unless we can change something”: consequences of intimate partner violence for indigenous women, children, and families

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    Background: Violence against indigenous women and girls is endemic, yet the absence of research on the consequences of this violence from the perspectives of women presents a profound barrier to the development of knowledge, along with violence prevention and mitigation. Although family is central to many indigenous communities, existing research typically examines the consequences of intimate partner violence (IPV) on women or children in isolation, rather than examining its consequences holistically. Objective: The purpose of this article is to identify US indigenous women's perspectives about the impact of IPV on women, children, and families. Method: Data were collected with 29 indigenous women affected by violence from a Southeastern tribe in the United States. As part of a larger critical ethnography, pragmatic horizon analysis of life history interviews revealed the consequences of IPV across multiple levels. Results: Women reported profound psychological consequences resulting from IPV. The majority of women had witnessed IPV in their childhood, providing support for an intergenerational cycle of violence. Women reported psychological consequences on children, which paralleled those reported by women, leaving deep impressions on children across their life course. Consequences on children and whole families were extensive, indicating the negative ramifications of IPV transcended personal boundaries and affected children and families across multiple generations. Conclusions: Given the tight-knit nature of indigenous families and communities, the consequences across individuals and families were noteworthy. However, a dearth in research examining consequences of IPV across levels fails to capture the interconnections of consequences for women, children, and families. Given the centrality of family in many indigenous communities, examining IPV from a holistic perspective that incorporates multiple levels is recommended for IPV research and intervention development

    An Online Growth Mindset Intervention in a Sample of Rural Adolescent Girls

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    Background. Students living in rural areas of the United States exhibit lower levels of educational attainment than their suburban counterparts. Innovative interventions are needed to close this educational gap. Aims. We investigated whether an online growth mindset intervention could be leveraged to promote academic outcomes. Sample. We tested the mindset intervention in a sample of 222 10th-grade adolescent girls (M age=15.2; 38% White, 25% Black, 29% Hispanic) from four rural, low-income high schools in Southeastern United States. Methods. We conducted a randomized controlled trial to test the efficacy of the growth mindset intervention, relative to a sexual health programme. We used random sampling and allocation procedures to assign girls to either the mindset intervention (n-115) or an attention-matched control programme (n-107). We assessed participants at pre-test, immediate post-test, and 4-month follow up. Results. Relative to the control condition, students assigned to the mindset intervention reported stronger growth mindsets at immediate post-test and 4-month follow up. Although the intervention did not have a total effect on academic attitudes or grades, it indirectly increased motivation to learn, learning efficacy and grades via the shifts in growth mindsets. Conclusions. Results indicate that this intervention is a promising method to encourage growth mindsets in rural adolescent girls

    Helicity at Photospheric and Chromospheric Heights

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    In the solar atmosphere the twist parameter α\alpha has the same sign as magnetic helicity. It has been observed using photospheric vector magnetograms that negative/positive helicity is dominant in the northern/southern hemisphere of the Sun. Chromospheric features show dextral/sinistral dominance in the northern/southern hemisphere and sigmoids observed in X-rays also have a dominant sense of reverse-S/forward-S in the northern/southern hemisphere. It is of interest whether individual features have one-to-one correspondence in terms of helicity at different atmospheric heights. We use UBF \Halpha images from the Dunn Solar Telescope (DST) and other \Halpha data from Udaipur Solar Observatory and Big Bear Solar Observatory. Near-simultaneous vector magnetograms from the DST are used to establish one-to-one correspondence of helicity at photospheric and chromospheric heights. We plan to extend this investigation with more data including coronal intensities.Comment: 5 pages, 1 figure, 1 table To appear in "Magnetic Coupling between the Interior and the Atmosphere of the Sun", eds. S.S. Hasan and R.J. Rutten, Astrophysics and Space Science Proceedings, Springer-Verlag, Heidelberg, Berlin, 200

    Limitations of Absolute Current Densities Derived from the Semel & Skumanich Method

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    Semel and Skumanich proposed a method to obtain the absolute electric current density, |Jz|, without disambiguation of 180 degree in the transverse field directions. The advantage of the method is that the uncertainty in the determination of the ambiguity in the magnetic azimuth is removed. Here, we investigate the limits of the calculation when applied to a numerical MHD model. We found that the combination of changes in the magnetic azimuth with vanishing horizontal field component leads to errors, where electric current densities are often strong. Where errors occur, the calculation gives |Jz| too small by factors typically 1.2 ~ 2.0.Comment: 10 pages, 4 figures. To appear on Science in China Series G: Physics, Mechanics & Astronomy, October 200

    Persistence of Natural Killer (NK) cell lymphocytosis with hyposplenism without development of leukaemia

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    BACKGROUND: Natural killer (NK) cell lymphocytosis usually has an indolent course and can progress into massive lymphocytosis with development of cytopenias and neoplastic diseases. NK-cells usually express one or more "NK-associated" antigens (CD16, CD56, CD57). Reactive expansions are seen in autoimmune diseases, viral infections, solid tumours and non-Hodgkin's lymphoma. CASE PRESENTATION: We report a lady with a benign clinical course over 10 years and persistent CD8+/CD3-/CD57+/CD16+ LGL proliferation with presence of Howell-Jolly bodies (functional hyposplenism), an association not previously described. CONCLUSION: We discuss the possible causes of clonal expansion and conclude that this may be part of the spectrum of immune dysregulation associated with NK-cell lymphocytosis

    Import of cytochrome c into mitochondria

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    The import of cytochrome c into mitochondria can be resolved into a number of discrete steps. Here we report on the covalent attachment of heme to apocytochrome c by the enzyme cytochrome c heme lyase in mitochondria from Neurospora crassa. A new method was developed to measure directly the linkage of heme to apocytochrome c. This method is independent of conformational changes in the protein accompanying heme attachment. Tryptic peptides of [35S]cysteine-labelled apocytochrome c, and of enzymatically formed holocytochrome c, were resolved by reverse-phase HPLC. The cysteine-containing peptide to which heme was attached eluted later than the corresponding peptide from apocytochrome c and could be quantified by counting 35S radioactivity as a measure of holocytochrome c formation. Using this procedure, the covalent attachment of heme to apocytochrome c, which is dependent on the enzyme cytochrome c heme lyase, could be measured. Activity required heme (as hemin) and could be reversibly inhibited by the analogue deuterohemin. Holocytochrome c formation was stimulated 5–10-fold by NADH > NADPH > glutathione and was independent of a potential across the inner mitochondrial membrane. NADH was not required for the binding of apocytochrome c to mitochondria and was not involved in the reduction of the cysteine thiols prior to heme attachment. Holocytochrome c formation was also dependent on a cytosolic factor that was necessary for the heme attaching step of cytochrome c import. The factor was a heat-stable, protease-insensitive, low-molecular-mass component of unknown function. Cytochrome c heme lyase appeared to be a soluble protein located in the mitochondrial intermembrane space and was distinct from the previously identified apocytochrome c binding protein having a similar location. A model is presented in which the covalent attachment of heme by cytochrome c heme lyase also plays an essential role in the import pathway of cytochrome c
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