99 research outputs found

    Design of stated adaptation experiments: discussion of some issues and experiences

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    Rescheduling of daily activities and associated travel in response to unforeseen events such as travel delays is receiving increased attention in the context of traffic management. In this paper, we describe the results of a stated adaptation experiment held among a large sample of individuals through a web-based questionnaire, to estimate parameters of such dynamic behaviour. In the experiment, subjects indicated their response to a reduction in available time for a planned activity in a number of hypothetical situations. A mixed logit model was used to estimate subjective preferences for adapting in certain ways conditional upon activity attributes and socio-economic variables. The results indicate that location and transport-mode adaptations are rare compared to duration adjustment or postponing/cancelling the activity, dependent on the relative size of reduced time. Socio-economic variables and activity attributes play a significant role too

    Quantized Roentgen Effect in Bose-Einstein Condensates

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    A classical dielectric moving in a charged capacitor can create a magnetic field (Roentgen effect). A quantum dielectric, however, will not produce a magnetization, except at vortices. The magnetic field outside the quantum dielectric appears as the field of quantized monopoles

    Platelets of patients with chronic kidney disease demonstrate deficient platelet reactivity in vitro

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    <p>Abstract</p> <p>Background</p> <p>In patients with chronic kidney disease studies focusing on platelet function and properties often are non-conclusive whereas only few studies use functional platelet tests. In this study we evaluated a recently developed functional flow cytometry based assay for the analysis of platelet function in chronic kidney disease.</p> <p>Methods</p> <p>Platelet reactivity was measured using flow cytometric analysis. Platelets in whole blood were triggered with different concentrations of agonists (TRAP, ADP, CRP). Platelet activation was quantified with staining for P-selectin, measuring the mean fluorescence intensity. Area under the curve and the concentration of half-maximal response were determined.</p> <p>Results</p> <p>We studied 23 patients with chronic kidney disease (9 patients with cardiorenal failure and 14 patients with end stage renal disease) and 19 healthy controls. Expression of P-selectin on the platelet surface measured as mean fluorescence intensity was significantly less in chronic kidney disease patients compared to controls after maximal stimulation with TRAP (9.7 (7.9-10.8) vs. 11.4 (9.2-12.2), Pā€‰=ā€‰0.032), ADP (1.6 (1.2-2.1) vs. 2.6 (1.9-3.5), Pā€‰=ā€‰0.002) and CRP (9.2 (8.5-10.8) vs. 11.5 (9.5-12.9), Pā€‰=ā€‰0.004). Also the area under the curve was significantly different. There was no significant difference in half-maximal response between both groups.</p> <p>Conclusion</p> <p>In this study we found that patients with chronic kidney disease show reduced platelet reactivity in response of ADP, TRAP and CRP compared to controls. These results contribute to our understanding of the aberrant platelet function observed in patients with chronic kidney disease and emphasize the significance of using functional whole blood platelet activation assays.</p

    High frequency diffraction of an electromagnetic plane wave by an imperfectly conducting rectangular cylinder

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    Copyright @ 2011 IEEEWe shall consider the the problem of determining the scattered far wave field produced when a plane E-polarized wave is incident on an imperfectly conducting rectangular cylinder. By using the the uniform asymptotic solution for the problem of the diffraction of a plane wave by a right-angled impedance wedge, in conjunction with Keller's method, the a high frequency far field solution to the problem is given

    Differential Form Valued Forms and Distributional Electromagnetic Sources

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    Properties of a fundamental double-form of bi-degree (p,p)(p,p) for pā‰„0p\ge 0 are reviewed in order to establish a distributional framework for analysing equations of the form Ī”Ī¦+Ī»2Ī¦=S\Delta \Phi + \lambda^2 \Phi = {\cal S} where Ī”\Delta is the Hodge-de Rham operator on pāˆ’p-forms Ī¦ \Phi on R3{\bf R}^3. Particular attention is devoted to singular distributional solutions that arise when the source S {\cal S} is a singular pāˆ’p-form distribution. A constructive approach to Dirac distributions on (moving) submanifolds embedded in R3{\bf R}^3 is developed in terms of (Leray) forms generated by the geometry of the embedding. This framework offers a useful tool in electromagnetic modeling where the possibly time dependent sources of certain physical attributes, such as electric charge, electric current and polarization or magnetization, are concentrated on localized regions in space.Comment: 40 page

    A rigorous analysis of high order electromagnetic invisibility cloaks

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    There is currently a great deal of interest in the invisibility cloaks recently proposed by Pendry et al. that are based in the transformation approach. They obtained their results using first order transformations. In recent papers Hendi et al. and Cai et al. considered invisibility cloaks with high order transformations. In this paper we study high order electromagnetic invisibility cloaks in transformation media obtained by high order transformations from general anisotropic media. We consider the case where there is a finite number of spherical cloaks located in different points in space. We prove that for any incident plane wave, at any frequency, the scattered wave is identically zero. We also consider the scattering of finite energy wave packets. We prove that the scattering matrix is the identity, i.e., that for any incoming wave packet the outgoing wave packet is the same as the incoming one. This proves that the invisibility cloaks can not be detected in any scattering experiment with electromagnetic waves in high order transformation media, and in particular in the first order transformation media of Pendry et al. We also prove that the high order invisibility cloaks, as well as the first order ones, cloak passive and active devices. The cloaked objects completely decouple from the exterior. Actually, the cloaking outside is independent of what is inside the cloaked objects. The electromagnetic waves inside the cloaked objects can not leave the concealed regions and viceversa, the electromagnetic waves outside the cloaked objects can not go inside the concealed regions. As we prove our results for media that are obtained by transformation from general anisotropic materials, we prove that it is possible to cloak objects inside general crystals.Comment: The final version is now published in Journal of Physics A: Mathematical and Theoretical, vol 41 (2008) 065207 (21 pp). Included in IOP-Selec

    Patient selection for LIVE therapy: from clinical indications to multimodality imaging individual case planning

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    Background Less Invasive Ventricular Enhancement (LIVE) with Revivent TC is an innovative therapy for symptomatic ischemic heart failure (HF). It is designed to reconstruct a negatively remodeled left ventricle (LV) after an anterior myocardial infarction (MI) by plication of the scar tissue. Its indications are specific, and as with any other structural heart intervention, the success of the procedure starts with appropriate patient selection. We aim to present the indications of the technique, crucial aspects in patient selection, and individual case planning approach. Methods and results After clinical evaluation, transthoracic echocardiography is the first imaging modality to be performed in a potential candidate for the therapy. However, definitive indication and detailed case planning rely on late gadolinium-enhanced cardiac magnetic resonance imaging or multiphasic contrast-enhanced cardiac computed tomography. These imaging modalities also assist with relative or absolute contra-indications for the procedure. Individual assessment is done to tailor the procedure to the specifics of the LV anatomy and location of the myocardial scar. Conclusion LIVE procedure is a unique intervention to treat symptomatic HF and ischemic cardiomyopathy after anterior MI. It is a highly customizable intervention that allows a patient-tailored approach, based on multimodality imaging assessment and planification

    Human CD1c+ DCs are critical cellular mediators of immune responses induced by immunogenic cell death

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    Chemotherapeutics, including the platinum compounds oxaliplatin (OXP) and cisplatin (CDDP), are standard care of treatment for cancer. Although chemotherapy has long been considered immunosuppressive, evidence now suggests that certain cytotoxic agents can efficiently stimulate antitumor responses, through the induction of a form of apoptosis, called immunogenic cell death (ICD). ICD is characterized by exposure of calreticulin and heat shock proteins (HSPs), secretion of ATP and release of high-mobility group box 1 (HMGB1). Proper activation of the immune system relies on the integration of these signals by dendritic cells (DCs). Studies on the crucial role of DCs, in the context of ICD, have been performed using mouse models or human in vitro-generated monocyte-derived DCs (moDCs), which do not fully recapitulate the in vivo situation. Here, we explore the effect of platinum-induced ICD on phenotype and function of human blood circulating DCs. Tumor cells were treated with OXP or CDDP and induction of ICD was investigated. We show that both platinum drugs triggered translocation of calreticulin and HSP70, as well as the release of ATP and HMGB1. Platinum treatment increased phagocytosis of tumor fragments by human blood DCs and enhanced phenotypic maturation of blood myeloid and plasmacytoid DCs. Moreover, upon interaction with platinum-treated tumor cells, CD1c+ DCs efficiently stimulated allogeneic proliferation of T lymphocytes. Together, our observations indicate that platinum-treated tumor cells may exert an active stimulatory effect on human blood DCs. In particular, these data suggest that CD1c+ DCs are critical mediators of immune responses induced by ICD

    The Boundary Conditions for Point Transformed Electromagnetic Invisibility Cloaks

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    In this paper we study point transformed electromagnetic invisibility cloaks in transformation media that are obtained by transformation from general anisotropic media. We assume that there are several cloaks located in different points in space. Our results apply in particular to the first order invisibility cloaks introduced by Pendry et al. and to the high order invisibility cloaks introduced by Hendi et al. and by Cai et al.. We identify the appropriate {\it cloaking boundary conditions} that the solutions of Maxwell equations have to satisfy at the outside, āˆ‚K+\partial K_+, and at the inside, āˆ‚Kāˆ’\partial K_-, of the boundary of the cloaked object KK. Namely, that the tangential components of the electric and the magnetic fields have to vanish at āˆ‚K+\partial K_+ -what is always true- and that the normal components of the curl of the electric and the magnetic fields have to vanish at āˆ‚Kāˆ’\partial K_-. These results are proven requiring that energy be conserved. In the case of one spherical cloak with a spherically stratified KK and a radial current at āˆ‚K\partial K we verify by an explicit calculation that our {\it cloaking boundary conditions} are satisfied and that cloaking of active devices holds even if the current is at the boundary of the cloaked object. As we prove our results for media that are obtained by transformation from general anisotropic media, our results apply to the cloaking of objects with active and passive devices contained in general anisotropic media, in particular to objects with active and passive devices contained inside general crystals.Comment: This final, published, version has been edited, comments have been adde
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