1,931 research outputs found

    Quantitative LSPR Imaging for Biosensing with Single Nanostructure Resolution

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    AbstractLocalized surface plasmon resonance (LSPR) imaging has the potential to map complex spatio-temporal variations in analyte concentration, such as those produced by protein secretions from live cells. A fundamental roadblock to the realization of such applications is the challenge of calibrating a nanoscale sensor for quantitative analysis. Here, we introduce a new, to our knowledge, LSPR imaging and analysis technique that enables the calibration of hundreds of individual gold nanostructures in parallel. The calibration allowed us to map the fractional occupancy of surface-bound receptors at individual nanostructures with nanomolar sensitivity and a temporal resolution of 225 ms. As a demonstration of the technique’s applicability to molecular and cell biology, the calibrated array was used for the quantitative LSPR imaging of anti-c-myc antibodies harvested from a cultured 9E10 hybridoma cell line without the need for further purification or processing

    Trends in Child Health Insurance Coverage: A Local Perspective

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    Background: Over the past decade, the percentage of Americans with access to employer-sponsored insurance (ESI) has declined. Dependents, specifically children, are the most likely to bear the burden of lost coverage. Objectives: The objectives of this study were to 1) describe trends in children’s health insurance taking into account the heterogeneity across different sub-populations and 2) assess the associations between individual, local (offers of ESI), and supply side (proximity to safety net hospitals) characteristics and children’s health insurance. Methods: We analyzed locally collected survey data for children living in the 12 counties of greater Houston, Texas (years 2003, 2006, 2008, 2011). For each year, telephone interviews were conducted with caregivers through random digit dialing. Among households with at least one employed caregiver (N=2,508), we performed an adjusted multinomial logistic regression analysis to evaluate the odds of being publicly insured or uninsured, with the option for ESI and proximity to a public hospital as primary independent variables. Results: Low-income and racial/ethnic minority children experienced the largest increases in coverage through public insurance. Children in households without the option for ESI had higher odds (Odds ratio 10.87, 95% confidence interval 7.31-16.17) of being publicly insured or uninsured (Odds ratio 9.50, 95% confidence interval 6.14-14.70) compared to those in households with the option for ESI. Proximity to a public hospital was not associated with being uninsured. Conclusions: As the availability of ESI has declined, public insurance has acted as a safety net for low-income and minority children. While access to free care plays an important role, it may not substitute for insurance coverage

    Response of the Great Barrier Reef to sea level and environmental changes over the past 30,000 years

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    Previous drilling through submerged fossil coral reefs has greatly improved our understanding of the general pattern of sea-level change since the Last Glacial Maximum, however, how reefs responded to these changes remains uncertain. Here we document the evolution of the Great Barrier Reef (GBR), the world\u27s largest reef system, to major, abrupt environmental changes over the past 30 thousand years based on comprehensive sedimentological, biological and geochronological records from fossil reef cores. We show that reefs migrated seaward as sea level fell to its lowest level during the most recent glaciation (~20.5-20.7 thousand years ago (ka)), then landward as the shelf flooded and ocean temperatures increased during the subsequent deglacial period (~20-10 ka). Growth was interrupted by five reef-death events caused by subaerial exposure or sea-level rise outpacing reef growth. Around 10 ka, the reef drowned as the sea level continued to rise, flooding more of the shelf and causing a higher sediment flux. The GBR\u27s capacity for rapid lateral migration at rates of 0.2-1.5 m yr−1 (and the ability to recruit locally) suggest that, as an ecosystem, the GBR has been more resilient to past sea-level and temperature fluctuations than previously thought, but it has been highly sensitive to increased sediment input over centennial-millennial timescales

    A novel cardiovascular magnetic resonance risk score for predicting mortality following surgical aortic valve replacement

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    The increasing prevalence of patients with aortic stenosis worldwide highlights a clinical need for improved and accurate prediction of clinical outcomes following surgery. We investigated patient demographic and cardiovascular magnetic resonance (CMR) characteristics to formulate a dedicated risk score estimating long-term survival following surgery. We recruited consecutive patients undergoing CMR with gadolinium administration prior to surgical aortic valve replacement from 2003 to 2016 in two UK centres. The outcome was overall mortality. A total of 250 patients were included (68 ± 12 years, male 185 (60%), with pre-operative mean aortic valve area 0.93 ± 0.32cm2, LVEF 62 ± 17%) and followed for 6.0 ± 3.3 years. Sixty-one deaths occurred, with 10-year mortality of 23.6%. Multivariable analysis showed that increasing age (HR 1.04, P = 0.005), use of antiplatelet therapy (HR 0.54, P = 0.027), presence of infarction or midwall late gadolinium enhancement (HR 1.52 and HR 2.14 respectively, combined P = 0.12), higher indexed left ventricular stroke volume (HR 0.98, P = 0.043) and higher left atrial ejection fraction (HR 0.98, P = 0.083) associated with mortality and developed a risk score with good discrimination. This is the first dedicated risk prediction score for patients with aortic stenosis undergoing surgical aortic valve replacement providing an individualised estimate for overall mortality. This model can help clinicians individualising medical and surgical care

    SPICES: Spectro-Polarimetric Imaging and Characterization of Exoplanetary Systems

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    SPICES (Spectro-Polarimetric Imaging and Characterization of Exoplanetary Systems) is a five-year M-class mission proposed to ESA Cosmic Vision. Its purpose is to image and characterize long-period extrasolar planets and circumstellar disks in the visible (450 - 900 nm) at a spectral resolution of about 40 using both spectroscopy and polarimetry. By 2020/22, present and near-term instruments will have found several tens of planets that SPICES will be able to observe and study in detail. Equipped with a 1.5 m telescope, SPICES can preferentially access exoplanets located at several AUs (0.5-10 AU) from nearby stars (<<25 pc) with masses ranging from a few Jupiter masses to Super Earths (\sim2 Earth radii, \sim10 M_{\oplus}) as well as circumstellar disks as faint as a few times the zodiacal light in the Solar System
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