5,370 research outputs found

    Association of lower extremity performance with cardiovascular and all-cause mortality in patients with peripheral artery disease: A systematic review and meta-analysis

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    Background: Peripheral artery disease (PAD) is associated with impaired mobility and a high rate of mortality. The aim of this systematic review was to investigate whether reduced lower extremity performance was associated with an increased incidence of cardiovascular and all‐cause mortality in people with PAD. Methods and Results: A systematic search of the MEDLINE, EMBASE, SCOPUS, Web of Science, and Cochrane Library databases was conducted. Studies assessing the association between measures of lower extremity performance and cardiovascular or all‐cause mortality in PAD patients were included. A meta‐analysis was conducted combining data from commonly assessed performance tests. The 10 identified studies assessed lower extremity performance by strength tests, treadmill walking performance, 6‐minute walk, walking velocity, and walking impairment questionnaire (WIQ). A meta‐analysis revealed that shorter maximum walking distance was associated with increased 5‐year cardiovascular (unadjusted RR=2.54, 95% CI 1.86 to 3.47, P<10−5, n=1577, fixed effects) and all‐cause mortality (unadjusted RR=2.23 95% CI 1.85 to 2.69, P<10−5, n=1710, fixed effects). Slower 4‐metre walking velocity, a lower WIQ stair‐climbing score, and poor hip extension, knee flexion, and plantar flexion strength were also associated with increased mortality. No significant associations were found for hip flexion strength, WIQ distance score, or WIQ speed score with mortality. Conclusions: A number of lower extremity performance measures are prognostic markers for mortality in PAD and may be useful clinical tools for identifying patients at higher risk of death. Further studies are needed to determine whether interventions that improve measures of lower extremity performance reduce mortality

    O/IR Polarimetry for the 2010 Decade (GAN): Science at the Edge, Sharp Tools for All

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    Science opportunities and recommendations concerning optical/infrared polarimetry for the upcoming decade in the field of Galactic science. Community-based White Paper to Astro2010 in response to the call for such papers.Comment: White Paper to the Galactic Neighborhood (GAN) Science Frontiers Panel of the Astro2010 Decadal Surve

    Retropharyngeal lipoblastoma causing severe pediatric obstructive sleep apnea

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    Lipoblastomas are benign neoplasms of white adipose which usually occupy the trunk and limbs in pediatric patients. They can seldomly involve the head and neck, usually as a lateral cervical mass. Magnetic resonance imaging is the most useful modality for identifying these lesions. Treatment involves complete excision, and patients are followed with serial exams and/or imaging as recurrence is more common in the head and neck. Here we present an exceedingly rare case of retropharyngeal lipoblastoma in a two-year-old male causing severe obstructive sleep apnea which was identified during adenotonsillectomy. As this mass can be mistaken for other more common masses of the retropharyngeal space, we review the differential diagnoses, imaging, and histopathologic features of this neoplasm, which was responsible for upper airway obstruction in this case

    Ice flow dynamics and surface meltwater flux at a land-terminating sector of the Greenland ice sheet

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    AbstractWe present satellite-derived velocity patterns for the two contrasting melt seasons of 2009–10 across Russell Glacier catchment, a western, land-terminating sector of the Greenland ice sheet which encompasses the K(angerlussuaq)-transect. Results highlight great spatial heterogeneity in flow, indicating that structural controls such as bedrock geometry govern ice discharge into individual outlet troughs. Results also reveal strong seasonal flow variability extending 57 km up-glacier to 1200 m elevation, with the largest acceleration (100% over 11 days) occurring within 10 km of the margin coincident with spring melt. By late July 2010, 2 weeks before peak melt and runoff, 48 % of the 2400 km2 catchment had slowed to less than the winter mean. This observation supports the hypothesis that the subglacial hydrological system evolves from an inefficient distributed to an efficient drainage system, regulating flow dynamics. Despite this, the cumulative surface flux over the record melt year of 2010 was still greater compared with the perturbation over the average melt year of 2009. This study supports the proposition that local surface meltwater runoff couples to basal hydrology driving ice-sheet dynamics, and although the effect is nonlinear, our observations indicate that greater meltwater runoff yields increased net flux over this sector of the ice sheet.</jats:p

    Behavioural, emotional, and cognitive responses in European disasters: results of survivor interviews

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    In the European multi-centre study BeSeCu (Behaviour, Security, Culture), interviews were conducted in seven countries to explore survivors’ emotional, behavioural, and cognitive responses during disasters. Interviews, either in groups or one-to-one, were convened according to type of event: collapse of a building; earthquake; fire; flood; and terror attack. The content analysis of interviews resulted in a theoretical framework, describing the course of the events, behavioural responses, and the emotional and cognitive processing of survivors. While the environmental cues and the ability to recognise what was happening varied in different disasters, survivors’ responses tended to be more universal across events, and most often were adaptive and non-selfish. Several peri-traumatic factors related to current levels of post-traumatic stress were identified, while memory quantity did not differ as a function of event type or post-traumatic stress. Time since the event had a minor effect on recall. Based on the findings, several suggestions for emergency training are made

    Birth Weight Reference for Triples in Korea

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    An estimation of the baseline value of birth weight depending on gestational age is helpful for reducing morbidity and mortality following the early diagnosis and treatment of intrauterine growth retardation. In Korea, there are established baseline values for singletons and twins. But no definite criteria exist for triplets yet. Given the above background, we obtained the baseline value of birth weight depending on the gestational age in triplets with a gestational age of 27-38 weeks using a raw data about birth records which had been obtained during a 10-yr period from 1998 to 2007. This baseline value was compared with those of singletons and twins. During the 10-yr period, the total number of newborns who were born between gestational age 27 and 38 was 1,330,822. Of these, the number of singletons, twins and triplets was 1,330,822, 90,245, and 840, respectively. A mean gestational age was 37.3±1.5 weeks, 36.0±2.0 weeks and 33.3±2.4 weeks in the corresponding order. A mean birth weight was 3,071±490 g, 2,414±455 g, and 1,836±454 g in the corresponding order. A comparison of the birth weight depending on the gestational age of triplets was made with the normal value of singletons and twins. According to this, in the overall gestational age ranging from weeks 27 to 38, it was relatively smaller as compared with the birth weight of twins and singletons. The current study was of significance in that it first obtained the normal value of birth weight of triplets in the overall gestational age ranging from weeks 27 to 38, whose results are expected to be helpful for studies or treatments of triplets

    Cryo-EM of multiple cage architectures reveals a universal mode of clathrin self assembly

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    Clathrin forms diverse lattice and cage structures that change size and shape rapidly in response to the needs of eukaryotic cells during clathrin-mediated endocytosis and intracellular trafficking. We present the cryo-EM structure and molecular model of assembled porcine clathrin, providing insights into interactions that stabilize key elements of the clathrin lattice, namely, between adjacent heavy chains, at the light chain–heavy chain interface and within the trimerization domain. Furthermore, we report cryo-EM maps for five different clathrin cage architectures. Fitting structural models to three of these maps shows that their assembly requires only a limited range of triskelion leg conformations, yet inherent flexibility is required to maintain contacts. Analysis of the protein–protein interfaces shows remarkable conservation of contact sites despite architectural variation. These data reveal a universal mode of clathrin assembly that allows variable cage architecture and adaptation of coated vesicle size and shape during clathrin-mediated vesicular trafficking or endocytosis

    Random single amino acid deletion sampling unveils structural tolerance and the benefits of helical registry shift on GFP folding and structure

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    Altering a protein’s backbone through amino acid deletion is a common evolutionary mutational mechanism, but is generally ignored during protein engineering primarily because its effect on the folding-structure-function relationship is difficult to predict. Using directed evolution, enhanced green fluorescent protein (EGFP) was observed to tolerate residue deletion across the breadth of the protein, particularly within short and long loops, helical elements, and at the termini of strands. A variant with G4 removed from a helix (EGFPG4Δ) conferred significantly higher cellular fluorescence. Folding analysis revealed that EGFPG4Δ retained more structure upon unfolding and refolded with almost 100% efficiency but at the expense of thermodynamic stability. The EGFPG4Δ structure revealed that G4 deletion caused a beneficial helical registry shift resulting in a new polar interaction network, which potentially stabilizes a cis proline peptide bond and links secondary structure elements. Thus, deletion mutations and registry shifts can enhance proteins through structural rearrangements not possible by substitution mutations alone

    Four-wave-mixing microscopy reveals non-colocalisation between gold nanoparticles and fluorophore conjugates inside cells

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    Gold nanoparticles have been researched for many biomedical applications in diagnostics, theranostics, and as drug delivery systems. When conjugated to fluorophores, their interaction with biological cells can be studied in situ and real time using fluorescence microscopy. However, an important question that has remained elusive to answer is whether the fluorophore is a faithful reporter of the nanoparticle location. Here, our recently developed four-wave-mixing optical microscopy is applied to image individual gold nanoparticles and in turn investigate their co-localisation with fluorophores inside cells. Nanoparticles from 10 nm to 40 nm diameter were conjugated to fluorescently-labeled transferrin, for internalisation via clathrin-mediated endocytosis, or to non-targeting fluorescently-labelled antibodies. Human (HeLa) and murine (3T3-L1) cells were imaged at different time points after incubation with these conjugates. Our technique identified that, in most cases, fluorescence originated from unbound fluorophores rather than from fluorophores attached to nanoparticles. Fluorescence detection was also severely limited by photobleaching, quenching and autofluorescence background. Notably, correlative extinction/fluorescence microscopy of individual particles on a glass surface indicated that commercial constructs contain large amounts of unbound fluorophores. These findings highlight the potential problems of data interpretation when reliance is solely placed on the detection of fluorescence within the cell, and are of significant importance in the context of correlative light electron microscopy
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