747 research outputs found

    The local environment as a supportive operator in innovation diffusion

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    Spatial patterns of technology diffusion determine the capacity of regions and cities to compete in a global market. It is therefore, important to know in what way the local environment can contribute to the attraction of new technology to business locations and what factors differentiate in the support of the local environment in this process. The article will take its starting point in the knowledge capacity of cities. It will then discuss conventional theory on spatial diffusion and review some merits of this theory. Furthermore. a focused approach will be introduced by adopting a communication perspective on technology diffusion. This perspective allows for an exploration of potential barriers (and bridges) in the diffusion process. The article will then present new empirical results on the supportive role of the local environment in technology diffusion on the basis of a large sample of innovative companies in various European cities. Particular attention will be given to the role of the local institutes of higher' education and research. This article will conclude with some policy recommendations on an improved use of the local environment in advancing the competitiveness of innovative companies

    Dewetting of thin polymer films: Influence of interface evolution

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    The dewetting dynamics of ultrathin polymer films, e.g. in the model system of polystyrene on a polydimethylsiloxane-covered substrate, exhibits interesting behavior like a fast decay of the dewetting velocity and a maximum in the width of the built-up rim in the course of time. These features have been recently ascribed to the relaxation of residual stresses in the film that stem from the nonequilibrium preparation of the samples. Recent experiments by Coppee et al. on PS with low molecular weight, where such stresses could not be evidenced, showed however similar behavior. By scaling arguments and numerical solution of a thin film viscoelastic model we show that the maximum in the width of the rim can be caused by a temporal evolution of the friction coefficient (or equivalently of the slip length), for which we discuss two possible mechanisms. In addition, the maximum in the width is affected by the sample age. As a consequence, knowing the temporal behavior of friction (or slip length) in principle allows to measure the aging dynamics of a polymer-polymer interface by simple dewetting experiments.Comment: 6 pages, 2 figure

    Dynamics of a faceted nematic-smectic B front in thin-sample directional solidification

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    We present an experimental study of the directional-solidification patterns of a nematic - smectic B front. The chosen system is C_4H_9-(C_6H_{10})_2CN (in short, CCH4) in 12 \mu m-thick samples, and in the planar configuration (director parallel to the plane of the sample). The nematic - smectic B interface presents a facet in one direction -- the direction parallel to the smectic layers -- and is otherwise rough, and devoid of forbidden directions. We measure the Mullins-Sekerka instability threshold and establish the morphology diagram of the system as a function of the solidification rate V and the angle theta_{0} between the facet and the isotherms. We focus on the phenomena occurring immediately above the instability threshold when theta_{0} is neither very small nor close to 90^{o}. Under these conditions we observe drifting shallow cells and a new type of solitary wave, called "faceton", which consists essentially of an isolated macroscopic facet traveling laterally at such a velocity that its growth rate with respect to the liquid is small. Facetons may propagate either in a stationary, or an oscillatory way. The detailed study of their dynamics casts light on the microscopic growth mechanisms of the facets in this system.Comment: 12 pages, 19 figures, submitted to Phys. Rev.

    Renal effects and associated outcomes during angiotensin-neprilysin inhibition in heart failure

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    Objectives: The purpose of this study was to evaluate the renal effects of sacubitril/valsartan in patients with heart failure and reduced ejection fraction. Background: Renal function is frequently impaired in patients with heart failure with reduced ejection fraction and may deteriorate further after blockade of the renin–angiotensin system. Methods: In the PARADIGM-HF (Prospective Comparison of ARNI with ACE inhibition to Determine Impact on Global Mortality and Morbidity in Heart Failure) trial, 8,399 patients with heart failure with reduced ejection fraction were randomized to treatment with sacubitril/valsartan or enalapril. The estimated glomerular filtration rate (eGFR) was available for all patients, and the urinary albumin/creatinine ratio (UACR) was available in 1872 patients, at screening, randomization, and at fixed time intervals during follow-up. We evaluated the effect of study treatment on change in eGFR and UACR, and on renal and cardiovascular outcomes, according to eGFR and UACR. Results: At screening, the eGFR was 70 ± 20 ml/min/1.73 m2 and 2,745 patients (33%) had chronic kidney disease; the median UACR was 1.0 mg/mmol (interquartile range: 0.4 to 3.2 mg/mmol) and 24% had an increased UACR. The decrease in eGFR during follow-up was less with sacubitril/valsartan compared with enalapril (−1.61 ml/min/1.73 m2/year; [95% confidence interval: −1.77 to −1.44 ml/min/1.73 m2/year] vs. −2.04 ml/min/1.73 m2/year [95% CI: −2.21 to −1.88 ml/min/1.73 m2/year ]; p < 0.001) despite a greater increase in UACR with sacubitril/valsartan than with enalapril (1.20 mg/mmol [95% CI: 1.04 to 1.36 mg/mmol] vs. 0.90 mg/mmol [95% CI: 0.77 to 1.03 mg/mmol]; p < 0.001). The effect of sacubitril/valsartan on cardiovascular death or heart failure hospitalization was not modified by eGFR, UACR (p interaction = 0.70 and 0.34, respectively), or by change in UACR (p interaction = 0.38). Conclusions: Compared with enalapril, sacubitril/valsartan led to a slower rate of decrease in the eGFR and improved cardiovascular outcomes, even in patients with chronic kidney disease, despite causing a modest increase in UACR

    Ventricular assist device implantation in a patient with systemic right ventricle and pectus excavatum

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    Systemic right ventricular failure is a common finding in patients with transposition of the great arteries. Some of these patients require ventricular assist device implantation. We describe the feasibility of HeartMate 3 [Abbott, Illinois, United States] implantation in a patient with transposition of the great arteries, high human leukocyte antigen sensitization, and severe pectus excavatum using a two-stage approach. Learning objectives: 1. To notice the challenges faced while implanting HeartMate 3 [Abbott, Illinois, United States] in patients with congenital heart disease and anatomical limitations. 2. To understand that despite the difficulties, HeartMate 3 implantation is possible, worthwhile, and sometimes the only choice in a patient with end-stage heart failure and congenital heart disease

    P2Y12 blocker monotherapy after percutaneous coronary intervention

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    For secondary prevention of coronary artery disease (CAD) antiplatelet therapy is essential. For patients undergoing a percutaneous coronary intervention (PCI) temporary dual antiplatelet platelet therapy (DAPT: aspirin combined with a P2Y12 blocker) is mandatory, but leads to more bleeding than single antiplatelet therapy with aspirin. Therefore, to reduce bleeding after a PCI the duration of DAPT is usually kept as short as clinically acceptable; thereafter aspirin monotherapy is administered. Another option to reduce bleeding is to discontinue aspirin at the time of DAPT cessation and thereafter to administer P2Y12 blocker monotherapy. To date, five randomised trials have been published comparing DAPT with P2Y12 blocker monotherapy in 32,181 stented patients. Also two meta-analyses addressing this novel therapy have been presented. P2Y12 blocker monotherapy showed a 50-60% reduction in major bleeding when compared to DAPT without a significant increase in ischaemic outcomes, including stent thrombosis. This survey reviews the findings in the current literature concerning P2Y12 blocker monotherapy after PCI
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