9 research outputs found

    A Hybrid Boundary Element Method for Elliptic Problems with Singularities

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    The singularities that arise in elliptic boundary value problems are treated locally by a singular function boundary integral method. This method extracts the leading singular coefficients from a series expansion that describes the local behavior of the singularity. The method is fitted into the framework of the widely used boundary element method (BEM), forming a hybrid technique, with the BEM computing the solution away from the singularity. Results of the hybrid technique are reported for the Motz problem and compared with the results of the standalone BEM and Galerkin/finite element method (GFEM). The comparison is made in terms of the total flux (i.e. the capacitance in the case of electrostatic problems) on the Dirichlet boundary adjacent to the singularity, which is essentially the integral of the normal derivative of the solution. The hybrid method manages to reduce the error in the computed capacitance by a factor of 10, with respect to the BEM and GFEM

    Droplet mobility manipulation on porous media using backpressure

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    Wetting phenomena on hydrophobic surfaces are strongly related to the volume and pressure of gas pockets residing at the solid–liquid interface. In this study, we explore the underlying mechanisms of droplet actuation and mobility manipulation when backpressure is applied through a porous medium under a sessile pinned droplet. Reversible transitions between the initially sticky state and the slippery states are thus incited by modulating the backpressure. The sliding angles of deionized (DI) water and ethanol in DI water droplets of various volumes are presented to quantify the effect of the backpressure on the droplet mobility. For a 50 μL water droplet, the sliding angle decreases from 45 to 0° when the backpressure increases to ca. 0.60 bar. Significantly smaller backpressure levels are required for lower surface energy liquids. We shed light on the droplet actuation and movement mechanisms by means of simulations encompassing the momentum conservation and the continuity equations along with the Cahn–Hilliard phase-field equations in a 2D computational domain. The droplet actuation mechanism entails depinning of the receding contact line and movement by means of forward wave propagation reaching the front of the droplet. Eventually, the droplet skips forward. The contact line depinning is also corroborated by analytical calculations based on the governing vertical force balance, properly modified to incorporate the effect of the backpressure. “This document is the Accepted Manuscript version of a Published Work that appeared in final form in LANGMUIR, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/acs.langmuir.6b00900

    Patient-reported treatment burden of chronic immune thrombocytopenia therapies

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    <p>Abstract</p> <p>Background</p> <p>Chronic immune thrombocytopenia (ITP) is a debilitating autoimmune disorder that causes a reduction in blood platelets and increased risk of bleeding. ITP is currently managed with various pharmacologic therapies and splenectomy.</p> <p>This study was conducted to assess patient perceived and reported treatment side effects, as well as the perceived burden or bother, and need to reduce or stop treatment, associated with these side effects among adult patients with chronic ITP.</p> <p>Methods</p> <p>A Web-enabled survey was administered to members of a US-based ITP patient support group. Patients reported demographic and clinical characteristics, ITP treatments' side effects for treatments received since diagnosed, level of bother (or distress), and need to reduce or stop treatment, associated with side effects. Current and past exposure was assessed for five specific treatment types: corticosteroids (CS), intravenous immunoglobulin (IVIg), anti-D immunoglobulin (anti-D), rituximab (RT), and splenectomy (SPL), as well as for other patient-referenced therapies (captured as "other").</p> <p>Results</p> <p>The survey was completed by 589 patients; 78% female, 89% white, mean age 48 years (SD = 14.71), and 68% reported a typical low platelet count of < 50,000/μL. Current or past treatment with CS was reported by 92% (n = 542) of patients, 56% (n = 322) for IVIg, 36% (n = 209) for anti-D, 36% (n = 213) for RT, and 39% (n = 227) for SPL. A substantial proportion of CS-treated patients reported side effects (98%, <it>P </it>< 0.05), were highly bothered by their side effects (53.1%, <it>P </it>< 0.05), and reported the need to stop or reduce treatment due to side effects (37.8%, <it>P </it>< 0.05). Among patients reporting side effects of treatment, significant associations were noted for the number of side effects, aggregate bother of reported side effects, and the need to stop or reduce treatment (all <it>P </it>< 0.05).</p> <p>Conclusions</p> <p>Current ITP treatments, particularly corticosteroids, are associated with multiple bothersome side effects that may lead to patients stopping or reducing therapy. Open, informed and complete communication between clinician and patient regarding both the benefits and the side effects of ITP treatment may better prepare patients for their prescribed regimens.</p

    Gold nanoparticles, radiations and the immune system: Current insights into the physical mechanisms and the biological interactions of this new alliance towards cancer therapy

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    Considering both cancer's serious impact on public health and the side effects of cancer treatments, strategies towards targeted cancer therapy have lately gained considerable interest. Employment of gold nanoparticles (GNPs), in combination with ionizing and non-ionizing radiations, has been shown to improve the effect of radiation treatment significantly. GNPs, as high-Z particles, possess the ability to absorb ionizing radiation and enhance the deposited dose within the targeted tumors. Furthermore, they can convert non-ionizing radiation into heat, due to plasmon resonance, leading to hyperthermic damage to cancer cells. These observations, also supported by experimental evidence both in vitro and in vivo systems, reveal the capacity of GNPs to act as radiosensitizers for different types of radiation. In addition, they can be chemically modified to selectively target tumors, which renders them suitable for future cancer treatment therapies. Herein, a current review of the latest data on the physical properties of GNPs and their effects on GNP circulation time, biodistribution and clearance, as well as their interactions with plasma proteins and the immune system, is presented. Emphasis is also given with an in depth discussion on the underlying physical and biological mechanisms of radiosensitization. Furthermore, simulation data are provided on the use of GNPs in photothermal therapy upon non-ionizing laser irradiation treatment. Finally, the results obtained from the application of GNPs at clinical trials and pre-clinical experiments in vivo are reported
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