403 research outputs found

    Alterations in vascular function in primary aldosteronism - a cardiovascular magnetic resonance imaging study

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    Introduction: Excess aldosterone is associated with increased cardiovascular risk. Aldosterone has a permissive effect on vascular fibrosis. Cardiovascular magnetic resonance imaging (CMR) allows study of vascular function by measuring aortic distensibility. We compared aortic distensibility in primary aldosteronism (PA), essential hypertension (EH) and normal controls and explored the relationship between aortic distensibility and pulse wave velocity (PWV).<p></p> Methods: We studied PA (n=14) and EH (n=33) subjects and age-matched healthy controls (n=17) with CMR, including measurement of aortic distensibility, and measured PWV using applanation tonometry. At recruitment, PA and EH patients had similar blood pressure and left ventricular mass.<p></p> Results: Subjects with PA had significantly lower aortic distensibilty and higher PWV compared to EH and healthy controls. These changes were independent of other factors associated with reduced aortic distensibility, including aging. There was a significant relationship between increasing aortic stiffness and age in keeping with physical and vascular aging. As expected, aortic distensibility and PWV were closely correlated.<p></p> Conclusion: These results demonstrate that PA patients display increased arterial stiffness compared to EH, independent of vascular aging. The implication is that aldosterone invokes functional impairment of arterial function. The long-term implications of arterial stiffening in aldosterone excess require further study.<p></p&gt

    Ensuring Security and Availability through Model-Based Cross-Layer Adaptation

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    Abstract. Situation- and resource-aware security is essential for the process control systems, composed of networked entities with sensors and actuators, that monitor and control the national critical infrastructure. However, security cannot be addressed at a single layer because of the inherent dependencies and tradeoffs among crosscutting concerns. Tech-niques applied at one layer to improve security affect security, timing, and power consumption at other layers. This paper argues for an integrated treatment of security across multiple layers of abstraction (application, middleware, operating system including network stack, and hardware). An important step in realizing this integrated treatment of situation-and resource-aware security is first understanding the cross-layer inter-actions between security policies and then exploiting these interactions to design efficient adaptation strategies (i) to balance security, quality of service, and energy needs, and (ii) to maximize system availability. We propose a novel approach that employs a compositional method within an iterative tuning framework based on lightweight formal methods with dynamic adaptation.

    Negotiating the Meaning of Team Expertise: A Firefighter Team’s Epistemic Denial

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    In this case study, we report how a team of firefighters critiqued one of its member’s decisions to facilitate learning and process improvement. The study is supported by 500+ hr of ethnographic observations, documents, and 11 retrospective interviews, which captured how the team’s talk about the member’s decision shaped their interpretations of their own and others’ expertise—interpretations that ironically undermined learning. Constant comparative analysis revealed that these firefighters positioned themselves as experts by crediting either personal experience or technical knowledge and then discrediting the alternative way of knowing. We labeled this process epistemic denial. The process of epistemic denial was rooted in identity concern; specifically, veteran team members relied on personal experience and newer members relied on technical information gained from training to assert their expertise, and to devalue others’ expertise. The article concludes with recommendations for avoiding problems associated with epistemic denial in high-reliability teams.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

    Beyond critique: the value of co-production in realising just cities?

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    This paper contributes to the burgeoning literature on the role of academic–practice relationships in contributing to sustainable urban development. We argue that co-production offers a potential pathway for academics to work with policy-makers in moving towards the realisation of more just cities. The paper starts from the position that there is an essential need for, but limit to, critique alone in contributing to the possibility of urban change. Moving towards a shared critique as a basis for future action is an important precondition for realising more just cities, adding weight to the voices arguing for alternative urban visions. These arguments are advanced through a study conducted by academic researchers and policy-makers in the Greater Manchester Low Carbon Hub. The paper outlines a process for working with existing urban institutions within institutional constraints to develop affirmative actions with the aim of longer term transformations. A key contribution is then the identification of eight markers for assessing progress towards the realisation of more just cities

    An Elevated Reservoir of Air Pollutants over the Mid-Atlantic States During the 2011 DISCOVER-AQ Campaign: Airborne Measurements and Numerical Simulations

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    During a classic heat wave with record high temperatures and poor air quality from July 18 to 23, 2011, an elevated reservoir of air pollutants was observed over and downwind of Baltimore, MD, with relatively clean conditions near the surface. Aircraft and ozonesonde measurements detected approximately 120 parts per billion by volume ozone at 800 meters altitude, but approximately 80 parts per billion by volume ozone near the surface. High concentrations of other pollutants were also observed around the ozone peak: approximately 300 parts per billion by volume CO at 1200 meters, approximately 2 parts per billion by volume NO2 at 800 meters, approximately 5 parts per billion by volume SO2 at 600 meters, and strong aerosol optical scattering (2 x 10 (sup 4) per meter) at 600 meters. These results suggest that the elevated reservoir is a mixture of automobile exhaust (high concentrations of O3, CO, and NO2) and power plant emissions (high SO2 and aerosols). Back trajectory calculations show a local stagnation event before the formation of this elevated reservoir. Forward trajectories suggest an influence on downwind air quality, supported by surface ozone observations on the next day over the downwind PA, NJ and NY area. Meteorological observations from aircraft and ozonesondes show a dramatic veering of wind direction from south to north within the lowest 5000 meters, implying that the development of the elevated reservoir was caused in part by the Chesapeake Bay breeze. Based on in situ observations, Community Air Quality Multi-scale Model (CMAQ) forecast simulations with 12 kilometers resolution overestimated surface ozone concentrations and failed to predict this elevated reservoir; however, CMAQ research simulations with 4 kilometers and 1.33 kilometers resolution more successfully reproduced this event. These results show that high resolution is essential for resolving coastal effects and predicting air quality for cities near major bodies of water such as Baltimore on the Chesapeake Bay and downwind areas in the Northeast

    Integrative genomic analyses reveal an androgen-driven somatic alteration landscape in early-onset prostate cancer

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    Early-onset prostate cancer (EO-PCA) represents the earliest clinical manifestation of prostate cancer. To compare the genomic alteration landscapes of EO-PCA with "classical" (elderly-onset) PCA, we performed deep sequencing-based genomics analyses in 11 tumors diagnosed at young age, and pursued comparative assessments with seven elderly-onset PCA genomes. Remarkable age-related differences in structural rearrangement (SR) formation became evident, suggesting distinct disease pathomechanisms. Whereas EO-PCAs harbored a prevalence of balanced SRs, with a specific abundance of androgen-regulated ETS gene fusions including TMPRSS2:ERG, elderly-onset PCAs displayed primarily non-androgen-associated SRs. Data from a validation cohort of > 10,000 patients showed age-dependent androgen receptor levels and a prevalence of SRs affecting androgen-regulated genes, further substantiating the activity of a characteristic "androgen-type" pathomechanism in EO-PCA

    Rapid preparation of nuclei-depleted detergent-resistant membrane fractions suitable for proteomics analysis

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    <p>Abstract</p> <p>Background</p> <p>Cholesterol-rich membrane microdomains known as lipid rafts have been implicated in diverse physiologic processes including lipid transport and signal transduction. Lipid rafts were originally defined as detergent-resistant membranes (DRMs) due to their relative insolubility in cold non-ionic detergents. Recent findings suggest that, although DRMs are not equivalent to lipid rafts, the presence of a given protein within DRMs strongly suggests its potential for raft association in vivo. Therefore, isolation of DRMs represents a useful starting point for biochemical analysis of lipid rafts. The physicochemical properties of DRMs present unique challenges to analysis of their protein composition. Existing methods of isolating DRM-enriched fractions involve flotation of cell extracts in a sucrose density gradient, which, although successful, can be labor intensive, time consuming and results in dilute sucrose-containing fractions with limited utility for direct proteomic analysis. In addition, several studies describing the proteomic characterization of DRMs using this and other approaches have reported the presence of nuclear proteins in such fractions. It is unclear whether these results reflect trafficking of nuclear proteins to DRMs or whether they arise from nuclear contamination during isolation. To address these issues, we have modified a published differential detergent extraction method to enable rapid DRM isolation that minimizes nuclear contamination and yields fractions compatible with mass spectrometry.</p> <p>Results</p> <p>DRM-enriched fractions isolated using the conventional or modified extraction methods displayed comparable profiles of known DRM-associated proteins, including flotillins, GPI-anchored proteins and heterotrimeric G-protein subunits. Thus, the modified procedure yielded fractions consistent with those isolated by existing methods. However, we observed a marked reduction in the percentage of nuclear proteins identified in DRM fractions isolated with the modified method (15%) compared to DRMs isolated by conventional means (36%). Furthermore, of the 21 nuclear proteins identified exclusively in modified DRM fractions, 16 have been reported to exist in other subcellular sites, with evidence to suggest shuttling of these species between the nucleus and other organelles.</p> <p>Conclusion</p> <p>We describe a modified DRM isolation procedure that generates DRMs that are largely free of nuclear contamination and that is compatible with downstream proteomic analyses with minimal additional processing. Our findings also imply that identification of nuclear proteins in DRMs is likely to reflect legitimate movement of proteins between compartments, and is not a result of contamination during extraction.</p
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