267 research outputs found

    Wetting of a symmetrical binary fluid mixture on a wall

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    We study the wetting behaviour of a symmetrical binary fluid below the demixing temperature at a non-selective attractive wall. Although it demixes in the bulk, a sufficiently thin liquid film remains mixed. On approaching liquid/vapour coexistence, however, the thickness of the liquid film increases and it may demix and then wet the substrate. We show that the wetting properties are determined by an interplay of the two length scales related to the density and the composition fluctuations. The problem is analysed within the framework of a generic two component Ginzburg-Landau functional (appropriate for systems with short-ranged interactions). This functional is minimized both numerically and analytically within a piecewise parabolic potential approximation. A number of novel surface transitions are found, including first order demixing and prewetting, continuous demixing, a tricritical point connecting the two regimes, or a critical end point beyond which the prewetting line separates a strongly and a weakly demixed film. Our results are supported by detailed Monte Carlo simulations of a symmetrical binary Lennard-Jones fluid at an attractive wall.Comment: submitted to Phys. Rev.

    Multi-modality image simulation with the Virtual Imaging Platform: Illustration on cardiac echography and MRI

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    International audienceMedical image simulation is useful for biological modeling, image analysis, and designing new imaging devices but it is not widely available due to the complexity of simulators, the scarcity of object models, and the heaviness of the associated computations. This paper presents the Virtual Imaging Platform, an openly-accessible web platform for multi-modality image simulation. The integration of simulators and models is described and exemplified on simulated cardiac MRIs and ultrasonic images

    A mutual reference shape based on information theory

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    International audienceIn this paper, we propose to consider the estimation of a refer-ence shape from a set of different segmentation results using both active contours and information theory. The reference shape is defined as the minimum of a criterion that benefits from both the mutual information and the joint entropy of the input segmentations and called a mutual shape. This energy criterion is here justified using similarities between informa-tion theory quantities and area measures, and presented in a continuous variational framework. This framework brings out some interesting evaluation measures such as the speci-ficity and sensitivity. In order to solve this shape optimization problem, shape derivatives are computed for each term of the criterion and interpreted as an evolution equation of an active contour. Some synthetical examples allow us to cast the light on the difference between our mutual shape and an average shape. Our framework has been considered for the estimation of a mutual shape for the evaluation of cardiac segmentation methods in MRI

    Flare hypercalcemia after letrozole in a patient with liver metastasis from breast cancer: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Tamoxifen may occasionally precipitate serious and potentially life-threatening hypercalcemia. However, to date, this has not been documented with aromatase inhibitors.</p> <p>Case presentation</p> <p>A 65-year-old Japanese woman with liver metastasis from breast cancer was admitted to our hospital with vomiting, anorexia, fatigue, arthralgia, muscle pain and dehydration. She had started a course of letrozole five weeks earlier. Our patient's calcium level was 11.6 mg/dL. She was rehydrated and elcatonin was administered. Our patient's parathyroid hormone and parathyroid hormone-related protein levels were not increased and a bone scintigram revealed no evidence of skeletal metastasis. After our patient's serum calcium level returned to within the normal range, letrozole was restarted at one-half of the previous dose (1.25 mg). There were no episodes of hypercalcemia. However, 84 days after restarting letrozole, our patient again complained of arthralgia and treatment was changed to toremifene. During these periods, repeated ultrasonograms revealed no progression of liver metastasis.</p> <p>Conclusion</p> <p>To the best of our knowledge, this is the first case report of flare hypercalcemia after treatment with letrozole in a patient with metastatic breast cancer.</p

    Wafer-Scale, Sub-5 nm Junction Formation by Monolayer Doping and Conventional Spike Annealing

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    We report the formation of sub-5 nm ultrashallow junctions in 4 inch Si wafers enabled by the molecular monolayer doping of phosphorous and boron atoms and the use of conventional spike annealing. The junctions are characterized by secondary ion mass spectrometry and non-contact sheet resistance measurements. It is found that the majority (~70%) of the incorporated dopants are electrically active, therefore, enabling a low sheet resistance for a given dopant areal dose. The wafer-scale uniformity is investigated and found to be limited by the temperature homogeneity of the spike anneal tool used in the experiments. Notably, minimal junction leakage currents (<1 uA/cm2) are observed which highlights the quality of the junctions formed by this process. The results clearly demonstrate the versatility and potency of the monolayer doping approach for enabling controlled, molecular-scale ultrashallow junction formation without introducing defects in the semiconductor.Comment: 21 pages, 5 figure

    Wages in high-tech start-ups - do academic spin-offs pay a wage premium?

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    Due to their origin from universities, academic spin‐offs operate at the forefront of the technological development. Therefore, spin‐offs exhibit a skill‐biased labour demand, i.e. spin‐offs have a high demand for employees with cutting edge knowledge and technical skills. In order to accommodate this demand, spin‐offs may have to pay a relative wage premium compared to other high‐tech start‐ups. However, neither a comprehensive theoretical assessment nor the empirical literature on wages in start‐ups unambiguously predicts the existence and the direction of wage differentials between spin‐offs and non‐spin‐offs. This paper addresses this research gap and examines empirically whether or not spin‐offs pay their employees a wage premium. Using a unique linked employer‐employee data set of German high‐tech start‐ups, we estimate Mincer‐type wage regressions applying the Hausman‐Taylor panel estimator. Our results show that spin‐offs do not pay a wage premium in general. However, a notable exception from this general result is that spin‐offs that commercialise new scientific results or methods provide higher wages to employees with linkages to the university sector – either as university graduates or as student workers

    Innovation capacity in the healthcare sector and historical anchors: examples from the UK, Switzerland and the US

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    Innovation is an integral part of economic development in developed economies. In the post 2008 period, a key policy agenda is that of sustainable development, which calls for innovation in all aspects of value-chains. In this paper, we focus on innovation from the biotech—pharma perspective to see whether or not this will lead to a sustainable future for the regions where there are clusters of firms in this sector. We examine data from a recently completed European Union study of innovation in the Healthcare sector from the UK and Switzerland, countries with an historical base in pharma, to understand how innovation pathways vary at the regional level in the broader life sciences, which incorporate biotech and more. Innovation in the healthcare sector in two regions, Oxfordshire in the UK and Zurich in Switzerland are compared. We contextualize our discussion by drawing on studies that focus on the sector in the US, specifically Boston. The analytical framework comprises three elements: innovation systems and national and regional economic development theories are the first two, followed by approaches which consider organizational or institutional activity. This framework is used to help explain and understand the complexity of how innovation is organized at the sub-national level. The overall context is that it is increasing becoming a condition for government financing of research that it has more immediate application in industry or have the possibility of commercialisation (e.g., translational research)
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