25 research outputs found

    Nonthrombogenic, Biodegradable Elastomeric Polyurethanes with Variable Sulfobetaine Content

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    For applications where degradable polymers are likely to have extended blood contact, it is often important for these materials to exhibit high levels of thromboresistance. This can be achieved with surface modification approaches, but such modifications may be transient with degradation. Alternatively, polymer design can be altered such that the bulk polymer is thromboresistant and this is maintained with degradation. Toward this end a series of biodegradable, elastic polyurethanes (PESBUUs) containing different zwitterionic sulfobetaine (SB) content were synthesized from a polycaprolactone-diol (PCL-diol):SB-diol mixture (100:0, 75:25, 50:50, 25:75 and 0:100) reacted with diisocyanatobutane and chain extended with putrescine. The chemical structure, tensile mechanical properties, thermal properties, hydrophilicity, biodegradability, fibrinogen adsorption and thrombogenicity of the resulting polymers was characterized. With increased SB content some weakening in tensile properties occurred in wet conditions and enzymatic degradation also decreased. However, at higher zwitterionic molar ratios (50% and 75%) wet tensile strength exceeded 15 MPa and breaking strain was >500%. Markedly reduced thrombotic deposition was observed both before and after substantial degradation for both of these PESBUUs and they could be processed by electrospinning into a vascular conduit format with appropriate compliance properties. The mechanical and degradation properties as well as the acute in vitro thrombogenicity assessment suggest that these tunable polyurethanes could provide options appropriate for use in blood contacting applications where a degradable, elastomeric component with enduring thromboresistance is desired

    Some terms are more interchangeable than others

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    This paper describes the work done by the Information Retrieval Research Group at Océ Technologies B.V., for the Cross-Language Evaluation Forum (CLEF) 2001. We have participated in the Dutch Monolingual task and submitted three runs. In this paper we introduce a new method for relevance computation using two new query operators. This method is meant to be applied to Multilingual Retrieval in the future.

    Océ at TREC 2003

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    This report describes the work done at OcĂ© Research for the TREC 2003. This first participation consists of ad hoc experiments for the Robust track. We used the BM25 model and our new probabilistic model to rank documents. Knowledge Concepts ’ Content Enabler semantic network was used for stemming and query expansion. Our main goal was to compare the BM25 model and the probabilistic model implemented with and/or without query expansion. The developed generic probabilistic model does not use global statistics of a document collection to rank documents. The relevance of the document to a given query is calculated using term frequencies of the query terms in the document and the length of the document. Furthermore, some theoretical research has been done. We have constructed a model that uses relevance judgements of previous years. However, we did not implement it due to the time constraints.

    Optical Response of Lumped-Element Kinetic-Inductance Detector Arrays

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    International audienceWe present an analysis of the optical response of lumped-element kinetic-inductance detector arrays, based on the NIKA2 1 mm array. This array has a dual-polarization sensitive Hilbert inductor for directly absorbing incident photons. We present the optical response calculated from a transmission line model, simulated with HFSS and measured using a Fourier transform spectrometer. We have estimated the energy absorbed by individual component of a pixel, such as the inductor. The difference between the absorption efficiencies is expected to be 20% from the simulations. The Fourier-transform spectroscopy measurement, performed on the actual NIKA2 arrays, validates our simulations. We discuss several possible ways to increase the absorption efficiency. This analysis can be used for optimization of the focal plane layout and can be extended to other kinetic inductance detector array designs in millimeter, submillimeter, and terahertz frequency bands

    Baseline surgical status and short-term mortality after extracorporeal membrane oxygenation for post-cardiotomy shock:a meta-analysis

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    Objective: While reported mortality rates on post-cardiotomy extracorporeal membrane oxygenation vary from center to center, impact of baseline surgical status (elective/urgent/emergency/salvage) on mortality is still unknown. Methods: A systematic search was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement using PubMed/Medline databases until March 2018 using the keywords "postcardiotomy," "cardiogenic shock," "extracorporeal membrane oxygenation," and "extracorporeal life support." Relevant articles were scrutinized and included in the meta-analysis only if reporting in-hospital/30-day mortality and baseline surgical status. The correlations between mortality and percentage of elective/urgent/emergency cases were investigated. Inference analysis of baseline status and extracorporeal membrane oxygenation complications was conducted as well. Results: Twenty-two studies (conducted between 1993 and 2017) enrolling N = 2,235 post-cardiotomy extracorporeal membrane oxygenation patients were found. Patients were mostly of non-emergency status (65.2%). Overall in-hospital/30-day mortality event rate (95% confidence intervals) was 66.7% (63.3-69.9%). There were no differences in in-hospital/30-day mortality with respect to baseline surgical status in the subgroup analysis (test for subgroup differences; p = 0.406). Similarly, no differences between mortality in studies enrolling 50% of emergency/salvage cases was found: respective event rates were 66.9% (63.1-70.4%) versus 64.4% (57.3-70.8%); p = 0.525. Yet, there was a significant positive association between increasing percentage of emergency/salvage cases and rates of neurological complications (p <0.001), limb complications (p <0.001), and bleeding (p = 0.051). Incidence of brain death (p = 0.099) and sepsis (p = 0.134) was increased as well. Conclusion: Other factors than baseline surgical status may, to a higher degree, influence the mortality in patients treated with extracorporeal membrane oxygenation for post-cardiotomy cardiogenic shock. Baseline status, however, strongly influences the complication occurrence while on extracorporeal membrane oxygenation

    Introducing Vigilant Audiences

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    This ground-breaking collection of essays examines the scope and consequences of digital vigilantism - a phenomenon emerging on a global scale, which sees digital audiences using social platforms to shape social and political life. Longstanding forms of moral scrutiny and justice seeking are disseminated through our contemporary media landscape, and researchers are increasingly recognising the significance of societal impacts effected by digital media. The authors engage with a range of cross-disciplinary perspectives in order to explore the actions of a vigilant digital audience - denunciation, shaming, doxing - and to consider the role of the press and other public figures in supporting or contesting these activities. In turn, the volume illuminates several tensions underlying these justice seeking activities - from their capacity to reproduce categorical forms of discrimination, to the diverse motivations of the wider audiences who participate in vigilant denunciations. This timely volume presents thoughtful case studies drawn both from high-profile Anglo-American contexts, and from developments in regions that have received less coverage in English-language scholarship. It is distinctive in its focus on the contested boundary between policing and entertainment, and on the various contexts in which the desire to seek retribution converges with the desire to consume entertainment. As with all Open Book publications, this entire book is available to read for free on the publisher’s website. Printed and digital editions, together with supplementary digital material, can also be found at www.openbookpublishers.co
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