491 research outputs found

    The association of early post-transplant glucose levels with long-term mortality

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    Aims/objective: We aimed to assess the long-term effects of post-transplant glycaemia on long-term survival after renal transplantation. Methods: Study participants were 1,410 consecutive transplant recipients without known diabetes who underwent an OGTT 10 weeks post-transplant and were observed for a median of 6.7 years (range 0.3–13.8 years). The HRs adjusted for age, sex, traditional risk factors and transplant-related risk factors were estimated. Results: Each 1 mmol/l increase in fasting plasma glucose (fPG) or 2 h plasma glucose (2hPG) was associated with 11% (95% CI −1%, 24%) and 5% (1%, 9%) increments in all-cause mortality risk and 19% (1%, 39%) and 6% (1%, 12%) increments in cardiovascular (CV) mortality risk, respectively. Including both fPG and 2hPG in the multi-adjusted model the HR for 2hPG remained unchanged, while the HR for fPG was attenuated (1.05 [1.00, 1.11] and 0.97 [0.84, 1.14]). Compared with recipients with normal glucose tolerance, patients with post-transplant diabetes mellitus had higher all-cause and CV mortality (1.54 [1.09, 2.17] and 1.80 [1.10, 2.96]), while patients with impaired glucose tolerance (IGT) had higher all-cause, but not CV mortality (1.39 [1.01, 1.91] and 1.04 [0.62, 1.74]). Conversely, impaired fasting glucose was not associated with increased all-cause or CV mortality (0.79 [0.52, 1.23] and 0.76 [0.39, 1.49]). Post-challenge hyperglycaemia predicted death from any cause and infectious disease in the multivariable analyses (1.49 [1.15, 1.95] and 1.91 [1.09, 3.33]). Conclusions/interpretation: For predicting all-cause and CV mortality, 2hPG is superior to fPG after renal transplantation. Also, early post-transplant diabetes, IGT and post-challenge hyperglycaemia were significant predictors of death. Future studies should determine whether an OGTT helps identify renal transplant recipients at increased risk of premature death. © The Author(s) 2011. This article is published with open access at Springerlink.co

    Investigation of diode-pumped 2.8-µm laser performance in Er:BaY2F8

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    Laser operation at 2.8 mm in BaY2F8 with erbium concentrations of 7.5% and 20% is investigated under laser-diode pumping at 967 nm. Output powers as high as 250 mW and slope efficiencies as high as 24% are obtained. Results are comparable with those of Er3+:LiYF4 under the same pump conditions. Slope efficiencies above 30% are predicted for optimized erbium concentrations

    Deep Image Translation with an Affinity-Based Change Prior for Unsupervised Multimodal Change Detection

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    Image translation with convolutional neural networks has recently been used as an approach to multimodal change detection. Existing approaches train the networks by exploiting supervised information of the change areas, which, however, is not always available. A main challenge in the unsupervised problem setting is to avoid that change pixels affect the learning of the translation function. We propose two new network architectures trained with loss functions weighted by priors that reduce the impact of change pixels on the learning objective. The change prior is derived in an unsupervised fashion from relational pixel information captured by domain-specific affinity matrices. Specifically, we use the vertex degrees associated with an absolute affinity difference matrix and demonstrate their utility in combination with cycle consistency and adversarial training. The proposed neural networks are compared with the state-of-the-art algorithms. Experiments conducted on three real data sets show the effectiveness of our methodology

    Code-Aligned Autoencoders for Unsupervised Change Detection in Multimodal Remote Sensing Images

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    Image translation with convolutional autoencoders has recently been used as an approach to multimodal change detection (CD) in bitemporal satellite images. A main challenge is the alignment of the code spaces by reducing the contribution of change pixels to the learning of the translation function. Many existing approaches train the networks by exploiting supervised information of the change areas, which, however, is not always available. We propose to extract relational pixel information captured by domain-specific affinity matrices at the input and use this to enforce alignment of the code spaces and reduce the impact of change pixels on the learning objective. A change prior is derived in an unsupervised fashion from pixel pair affinities that are comparable across domains. To achieve code space alignment, we enforce pixels with similar affinity relations in the input domains to be correlated also in code space. We demonstrate the utility of this procedure in combination with cycle consistency. The proposed approach is compared with the state-of-the-art machine learning and deep learning algorithms. Experiments conducted on four real and representative datasets show the effectiveness of our methodology

    Homocysteine Levels, Haemostatic Risk Factors and Patency Rates after Endovascular Treatment of the Above-Knee Femoro-Popliteal Artery

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    AbstractObjectives. To investigate the relationship between plasma homocysteine and other haemostatic variables and restenoses or reocclusions after endovascular treatment of symptomatic atherosclerosis of the above-knee femoro-popliteal artery.Design. Prospective observational study.Setting. University hospital.Patients and methods. The study included 103 patients (116 limbs), treated with subintimal angioplasty in 58 cases (50%) and with intraluminal PTA in 58 (50%): 39 (34%) patients were treated for critical limb ischaemia. Blood samples for analyses of fasting plasma values of homocysteine, fibrinogen, D-dimer, activated protein C resistance were drawn upon admission. Median follow-up for all procedures was 11 months (range 0–42 months). Outcome events (arterial patency) were defined as ≥50% restenosis or reocclusion in the treated arterial segment. Patency rates were estimated with the product limit method and Kaplan–Meier curves. Variables found to be related significantly to patency were included in multivariate analysis performed with the Cox proportional hazard model.Results. The 1-year cumulative primary patency rate for all procedures was 48%. One-year limb salvage rate in cases of critical ischaemia was 74%. Multivariate analysis demonstrated significant independent associations between patency rates and plasma D-dimer, diabetes mellitus, the nature of the lesion treated (stenosis vs. occlusion) and antithrombotic therapy with aspirin after the procedure. Plasma levels of homocysteine, fibrinogen or activated protein C resistance were not associated with patency rates. Homocysteine levels were higher in patients with critical limb ischaemia than those with intermittent claudication.Conclusions. Early restenosis or reocclusion after endovascular intervention of lesions in the above-knee femoro-popliteal artery was more frequent following treatment of occlusion (versus stenosis), for patients with diabetes, patients with elevated D-dimer and those without antithrombotic therapy after the procedure. Plasma homocysteine did not appear to influence the outcome of endovascular intervention

    Monitoring Chemical Pollution in Europe’s Seas: Programmes, practices and priorities for research

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    This report has been produced by the Marine Board Working Group on Existing and Emerging Chemical Pollutants (WGPOL) first convened in 2008 and tasked to examine the assessment and monitoring of existing and emerging chemicals in the European marine and coastal environment. The Working Group considered (i) existing monitoring/assessment frameworks; (ii) current monitoring practices; and (iii) new and emerging chemicals of concern and the mechanisms used to include them in current monitoring programmes. The primary conclusions and recommendations of this position paper are: 1. Fully implement state of the art environmental risk assessment procedures (combining exposure and effect assessment) to evaluate the full impact of chemical substances on the different compartments of coastal and open sea systems. 2. Further improve the coordination, cooperation and harmonization between existing monitoring efforts and those under development, to avoid duplication of effort, loss of expertise and a reduced willingness to fulfil the obligations towards regional conventions. 3. Ensure that the development and implementation of monitoring programmes for the assessment of chemicals in marine and coastal environment are based on a science-based and dynamic process. 4. Apply more resources targeted at developing appropriate approaches, tools and practices (education and training) to improve the acquisition and management of monitoring data. In addition to the above main recommendations, two further recommendations have been identified on the basis of two specific case studies which form part of this paper and which focus on the release, effects and monitoring of (i) hydrophobic and insoluble chemicals in the marine environment from merchant shipping; and (ii) chemicals released by the offshore oil-industry in the North Sea. These case studies highlighted the need to: 5. Develop a consistent, pan-European or regional (legal) framework/regulation which covers the activities of the oil and gas industry at sea. At the same time, more information and research is needed on the release and the effects of chemicals arising from offshore oil and gas activities. 6. Develop and apply state-of-the-art environmental risk assessment procedures (combining exposure and effect assessments, including on human health) to evaluate the impact of noxious liquid substances listed under MARPOL Annex II on the different compartments in coastal and open sea ecosystems

    Multidimensional Conservation Laws: Overview, Problems, and Perspective

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    Some of recent important developments are overviewed, several longstanding open problems are discussed, and a perspective is presented for the mathematical theory of multidimensional conservation laws. Some basic features and phenomena of multidimensional hyperbolic conservation laws are revealed, and some samples of multidimensional systems/models and related important problems are presented and analyzed with emphasis on the prototypes that have been solved or may be expected to be solved rigorously at least for some cases. In particular, multidimensional steady supersonic problems and transonic problems, shock reflection-diffraction problems, and related effective nonlinear approaches are analyzed. A theory of divergence-measure vector fields and related analytical frameworks for the analysis of entropy solutions are discussed.Comment: 43 pages, 3 figure
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