29 research outputs found

    Scattering hypervolume for ultracold bosons from weak to strong interactions

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    The elastic scattering properties of three bosons at low energy enter the many-body description of ultracold Bose gases via the three-body scattering hypervolume DD. We study this quantity for identical bosons that interact via a pairwise finite-range potential. Our calculations cover the regime from strongly repulsive potentials towards attractive potentials supporting multiple two-body bound states and are consistent with the few existing predictions for DD. We present the first numerical confirmation of the universal predictions for DD in the strongly interacting regime, where Efimov physics dominates, for a local nonzero-range potential. Our findings highlight how DD is influenced by three-body quasibound states with strong dd-wave or gg-wave characteristics in the weakly interacting regime.Comment: 13 pages, 8 figure

    Extreme roll motions of ships

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    The ship capsizing problem is one of the major challenges in naval architecture. The criterion of the International Maritime Organization (IMO) regarding capsize stability is still not including dynamic loads. Existing mathematical models of ships taking into account all degrees of freedom as well as fluid-structure-interaction can hardly be used for stability analysis with common methods from nonlinear dynamics theory due to their complexity. For the development of new better suited models a test environment has been created. A first prototype for an experimental capsize analysis is presented in this paper

    Early treatment with intravenous lipid emulsion in a potentially lethal hydroxychloroquine intoxication

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    This case report describes the possible benefit of intravenous lipid emulsion in two patients surviving a severe intoxication with hydroxychloroquine in a dose that was previously considered to be lethal. The first case involves a 25-year-old female who ingested 17.5 grams of hydroxychloroquine, approximately one hour before presentation. An ECG showed QRS widening and the lab results showed hypokalaemia. She became unconscious, and developed hypotension and eventually apnoea. After intubation, supportive care consisted of norepinephrine and supplementation of potassium. Moreover, sodium bicarbonate and intravenous lipid emulsion were started to prevent cardiac toxicity. After these interventions, haemodynamic stability was established within a few hours. Although cardiomyopathy was confirmed, the patient recovered after two weeks. The second case concerns a 25-year-old male who took 5 grams of hydroxychloroquine. At presentation, two hours after intake, he showed QTc prolongation and hypokalaemia. The patient was treated with the usual supportive care and, although presentation to hospital was later, with intravenous lipid emulsion. Also this patient recovered. In conclusion, these cases show the benefit of supplemental intravenous lipid emulsion to prevent cardiac toxicity after a severe intoxication with hydroxychloroquine

    Elastic scattering of three ultracold bosons

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    Elastic scattering of three bosons at low energy is a fundamental problem in the many-body description of ultracold Bose gases, entering via the three-body scattering hypervolume DD. We study this quantity for identical bosons that interact via a pairwise finite-range potential. Our calculations cover the regime from strongly repulsive potentials towards attractive potentials supporting multiple two-body bound states and are consistent with the few existing predictions for DD. We present the first numerical confirmation of the universal predictions for DD that are made in the strongly-interacting regime, where Efimov physics dominates, for a local nonzero-range potential. Our findings highlight how finite-range effects, such as dd-wave interactions, become important as the interaction strength is reduced

    DIY electromagnetic phantoms for biomedical wireless power transfer experiments

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    To perform biomedical Wireless Power Transfer experiments at UHF and microwave frequencies, a need exists for recipes and procedures to construct human tissue mimicking phantoms. This paper outlines the procedure for realizing body-mimicking phantoms and provides some recipes based on demineralized water, sugar (sucrose) and salt (NaCl). Even without using preservatives all samples made for this research maintained the dielectric characteristics for at least ten days when stored at room temperature. A procedure to construct a low-cost RG405 semi-rigid coaxial waveguide-based measurement probe and calibration method are discussed as well. The absolute error in obtained relative permittivity, using this probe, relative to using a Commercially Off The Shelf probe is less than 2.0

    Ribavirin-induced externalization of phosphatidylserine in erythrocytes is predominantly caused by inhibition of aminophospholipid translocase activity

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    Ribavirin in combination with interferon-alpha is the standard treatment for chronic hepatitis C, but often induces severe anemia forcing discontinuation of the therapy. Whereas suppression of bone marrow by interferon may impact on the production of erythrocytes, it has been suggested that accumulation of ribavirin in erythrocytes induces alterations causing an early removal of these cells by the mononuclear phagocytic system. Externalization of phosphatidylserine, which is exclusively present in the cytoplasmic leaflet of the plasma membrane, is a recognition signal for phagocytosis in particular of apoptotic cells. Here, we demonstrate that surface exposure of phosphatidylserine upon prolonged treatment of erythrocytes with ribavirin results mainly from inactivation of the aminophospholipid translocase, an ATP-dependent lipid pump, which specifically transports phosphatidylserine from the outer to the inner leaflet of the plasma membrane. Inactivation is due to severe ATP depletion, although competitive inhibition by ribavirin or its phosphorylated derivatives cannot be excluded. Phospholipid scramblase, responsible for collapse of lipid asymmetry, appears to be of minor importance as erythrocytes of patients with the Scott syndrome, lacking Ca(2+)-induced lipid scrambling, are equally sensitive to ribavirin treatment. Neither the antioxidant N-acetylcysteine nor the pan-caspase inhibitor Q-VD-OPH did affect ribavirin-induced phosphatidylserine exposure, suggesting that oxidative stress or apoptotic-related mechanisms are not involved in this process. In conclusion, we propose that spontaneous loss of lipid asymmetry, not corrected by aminophospholipid translocase activity, is the mechanism for ribavirin-induced phosphatidylserine exposure that may contribute to ribavirin-induced anemia

    A Novel Framework for the Optimization of Simultaneous ThermoBrachyTherapy

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    In high-dose-rate brachytherapy (HDR-BT) for prostate cancer treatment, interstitial hyperthermia (IHT) is applied to sensitize the tumor to the radiation (RT) dose, aiming at a more efficient treatment. Simultaneous application of HDR-BT and IHT is anticipated to provide maximum radiosensitization of the tumor. With this rationale, the ThermoBrachyTherapy applicators have been designed and developed, enabling simultaneous irradiation and heating. In this research, we present a method to optimize the three-dimensional temperature distribution for simultaneous HDR-BT and IHT based on the resulting equivalent physical dose (EQDphys) of the combined treatment. First, the temperature resulting from each electrode is precomputed. Then, for a given set of electrode settings and a precomputed radiation dose, the EQDphys is calculated based on the temperature-dependent linear-quadratic model. Finally, the optimum set of electrode settings is found through an optimization algorithm. The method is applied on implant geometries and anatomical data of 10 previously irradiated patients, using reported thermoradiobiological parameters and physical doses. We found that an equal equivalent dose coverage of the target can be achieved with a physical RT dose reduction of 20% together with a significantly lower EQDphys to the organs at risk (p-value < 0.001), even in the least favorable scenarios. As a result, simultaneous ThermoBrachy-Therapy could lead to a relevant therapeutic benefit for patients with prostate cancer
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