1,638 research outputs found

    Towards 100 % recycling of reclaimed asphalt in road surface courses: binder design methodology and case studies

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    Reclaimed Asphalt (RA) has shown great potential to be reused in new asphalt mixtures, however its incorporation in top asphalt pavement layers is still very limited (10-30%). In fact, despite the advantages that its use implies, RA content in road pavement surface courses is still restricted in most countries due to mainly legislation limitations, but also some technical issues. This paper aims at being a step further to improve the latter by providing a methodology that allows producing fundamental inputs for confidently performing mix design of asphalt mixtures incorporating up to 100% RA. The methodology consists in an advanced preliminary binder’s blend design that can be used with any type of RA and also in presence of rejuvenators. This procedure includes in the production of blending charts and laws that considers the uncertainties on accounting the extent of final binder content, Degree of Blending and Replaced Virgin Binder. The description of the methodology is accompanied with results of two extreme case studies consisting in the preliminary design of binders for asphalt mixtures with high content of two types of RA corresponding to extreme cases: the short-term aged RA (STA-RA), having a very soft residual binder (Pen> 20dmm) and the long-term aged RA, having a much harder residual binder (Pen <10dmm). As a result, the proposed methodology allowed assessing the feasibility of using up to 90% of RA and determining whether the use of rejuvenating agents was needed

    Expression of green fluorescent protein in human foreskin fibroblasts for use in 2D and 3D culture models

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    ABSTRACT The availability of fibroblasts that express green fluorescent protein (GFP) would be of interest for the monitoring of cell growth, migration, contraction, and other processes within the fibroblast-populated collagen matrix and other culture systems. A plasmid lentiviral vector-GFP (pLV-GFP) was utilized for gene delivery to produce primary human foreskin fibroblasts (HFFs) that stably express GFP. Cell morphology, cell migration, and collagen contraction were compared between nontransduced HFFs and transduced GFP-HFFs; no differences were observed. Immunocytochemical staining showed no differences in cell morphology between nontransduced and GFP-HFFs in both two-dimensional and three-dimensional culture systems. Furthermore, there was no significant difference in cellular population growth within the collagen matrix populated with nontransduced vs. GFP-HFFs. Within the limits of our assays, we conclude that transduction of GFP into HFFs did not alter the observed properties of HFFs compared with nontransduced fibroblasts. The GFP-HFFs may represent a new tool for the convenient monitoring of living primary fibroblast processes in two-dimensional or three-dimensional culture. Since the 1980s, the fibroblast-populated three-dimensional (3D) collagen matrix (FPCM) culture system has been used to model wound contraction, 1,2 cellular migration/motility, 1,3 and other phenomena. The cells exert tension on the matrix 4 and in some cases develop a myofibroblast phenotype similar to that in some healing wounds. 2,5 Although the FPCM model may be more physiologically relevant than a two-dimensional (2D) cell culture model, use of the former has been associated with a number of technical issues, such as reagent molecule absorption to collagen, interference of the collagen with protein assays, and obfuscation of cellular morphology in living (unstained) samples. 6 This latter issue makes tracking of living cells within the collagen matrix difficult. The ability to track living cells within the 3D collagen matrix would facilitate the study of fibroblast migration and motility; such an ability would be relevant to chemotaxis, granulation tissue formation, wound contraction, and other healing-related phenomena. 9 Green fluorescent protein (GFP) has been used as a marker or gene activity and asa label for proteins and subcellular compartments within living cells. 10 In addition, GFP-labeled cells can be tracked in tissues and used in numerous GFP-based biochemical sensor applications. 11,12 The availability of stable GFP-expressing primary human fibroblasts would be useful for studying cell growth, migration, and contraction within the 3D collagen matrix model. The purpose of the present report was to determine whether GFP expression affected select fibroblast functions and to investigate possible applications of GFP-expressing fibroblasts in 2D and 3D in vitro culture systems

    Prioritisation of Clinical Research by the Example of Type 2 Diabetes: A Caregiver-Survey on Perceived Relevance and Need for Evidence

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    BACKGROUND: The Cochrane Collaboration aims at providing the best available evidence for interventions in health care. We wished to examine to which extent treatments considered relevant by caregivers in type 2 diabetes are covered by Cochrane systematic reviews. METHODOLOGY/PRINCIPAL FINDINGS: 130 different interventions in type 2 diabetes were identified based on a review of clinical practice guidelines and expert opinion (Table S1). 459 members of the German Diabetes Society (diabetologists, general practitioners, diabetic nurses, nutritionists, podologists, others) were surveyed via e-mail-list to rank a) the perceived clinical relevance and b) the perceived need for evidence of interventions, based on an internet survey. In the Cochrane Library, there were, at the time of this evaluation, 56 reviews on interventions in diabetes. Generally, coverage of topics by Cochrane reviews reflected the perceived clinical relevance and perceived need for evidence. As an example, highly ranked treatments such as lifestyle changes or oral antidiabetics were well covered, while low rank treatments such as complementary approaches were not covered. Discrepancies occurred with new treatments such as amylin-analogues (low relevance, high need for evidence, review not yet completed) and interventions with immediate and dramatic effects such as treating hypoglycemia (high relevance, low need for evidence, no review). Also, there was a relative scarcity of reviews concerning specific problems, in particular, treatment of late diabetic complications. CONCLUSIONS/SIGNIFICANCE: For most interventions, perceived relevance and perceived need for evidence are reflected by the evidence already available. Prioritizing should aim at improving immediacy and consideration of the treatment of complications

    Using network theory to identify the causes of disease outbreaks of unknown origin.

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    The identification of undiagnosed disease outbreaks is critical for mobilizing efforts to prevent widespread transmission of novel virulent pathogens. Recent developments in online surveillance systems allow for the rapid communication of the earliest reports of emerging infectious diseases and tracking of their spread. The efficacy of these programs, however, is inhibited by the anecdotal nature of informal reporting and uncertainty of pathogen identity in the early stages of emergence. We developed theory to connect disease outbreaks of known aetiology in a network using an array of properties including symptoms, seasonality and case-fatality ratio. We tested the method with 125 reports of outbreaks of 10 known infectious diseases causing encephalitis in South Asia, and showed that different diseases frequently form distinct clusters within the networks. The approach correctly identified unknown disease outbreaks with an average sensitivity of 76 per cent and specificity of 88 per cent. Outbreaks of some diseases, such as Nipah virus encephalitis, were well identified (sensitivity = 100%, positive predictive values = 80%), whereas others (e.g. Chandipura encephalitis) were more difficult to distinguish. These results suggest that unknown outbreaks in resource-poor settings could be evaluated in real time, potentially leading to more rapid responses and reducing the risk of an outbreak becoming a pandemic

    Dogs with separation-related problems show a “less pessimistic” cognitive bias during treatment with fluoxetine (Reconcile™) and a behaviour modification plan

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    Background Canine separation-related problems (SRP) (also described as “separation anxiety” or “separation distress”) are among the most common behavioural complaints of dog owners. Treatment with psychoactive medication in parallel with a behaviour modification plan is well documented in the literature, but it is unknown if this is associated with an improvement in underlying affective state (emotion and mood) or simply an inhibition of the behaviour. Cognitive judgement bias tasks have been proposed as a method for assessing underlying affective state and so we used this approach to identify if any change in clinical signs during treatment was associated with a consistent change in cognitive bias (affective state). Five dogs showing signs of SRP (vocalising – e.g. barking, howling-, destruction of property, and toileting – urination or defecation- when alone) were treated with fluoxetine chewable tablets (Reconcile™) and set on a standard behaviour modification plan for two months. Questionnaires and interviews of the owners were used to monitor the clinical progress of the dogs. Subjects were also evaluated using a spatial cognitive bias test to infer changes in underlying affect prior to, and during, treatment. Concurrently, seven other dogs without signs of SRP were tested in the same way to act as controls. Furthermore, possible correlations between cognitive bias and clinical measures were also assessed for dogs with SRP. Results Prior to treatment, the dogs with SRP responded to ambiguous positions in the cognitive bias test negatively (i.e. with slower running speeds) compared to control dogs (p &lt; 0.05). On weeks 2 and 6 of treatment, SRP dogs displayed similar responses in the cognitive bias test to control dogs, consistent with the possible normalization of affect during treatment, with this effect more pronounced at week 6 (p &gt; 0.05). Questionnaire based clinical measures were significantly correlated among themselves and with performance in the cognitive bias test. Conclusion These results demonstrate for the first time that the clinical treatment of a negative affective state and associated behaviours in a non-human species can produce a shift in cognitive bias. These findings demonstrate how the outcome of an intervention on a clinical problem can be evaluated to determine not only that the subject’s behaviour has improved, but also its psychological state (welfare

    Opto-mechanical design for sight windows under high loads

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    In this study, the design aspects of optically accessible pressure vessels are investigated via a case study of a High Pressure Combustor experimental rig. The rig was designed to take optical measurements of combustion, simulating the conditions found in internal combustion engines and turbines. Although, it is not new to equip chambers and reactors with sight windows, important aspects of design and relevant information regarding optical access is missing or are insufficiently explored or not readily accessible in the existing literature. A comprehensive review of requirements for optical access to such high-pressure, high-temperature systems has been conducted. It is shown in a readily-navigable format as function of application and precision, with data and technical correlations hitherto not found in a ‘user-friendly’ style. The material selection procedure is detailed and supported by a complete comparison of optical materials and relevant properties. The review revealed a significant inconsistency in mechanical properties claimed in the literature for optical materials. As a response to this, increased safety factor values are suggested as function of level of uncertainties and effects of failure, typically three to four times higher than the industrial standard. Moreover, newly developed equations are presented linking performance analysis to the design criteria

    The Rossiter-McLaughlin effect in Exoplanet Research

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    The Rossiter-McLaughlin effect occurs during a planet's transit. It provides the main means of measuring the sky-projected spin-orbit angle between a planet's orbital plane, and its host star's equatorial plane. Observing the Rossiter-McLaughlin effect is now a near routine procedure. It is an important element in the orbital characterisation of transiting exoplanets. Measurements of the spin-orbit angle have revealed a surprising diversity, far from the placid, Kantian and Laplacian ideals, whereby planets form, and remain, on orbital planes coincident with their star's equator. This chapter will review a short history of the Rossiter-McLaughlin effect, how it is modelled, and will summarise the current state of the field before describing other uses for a spectroscopic transit, and alternative methods of measuring the spin-orbit angle.Comment: Review to appear as a chapter in the "Handbook of Exoplanets", ed. H. Deeg & J.A. Belmont
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