49 research outputs found

    Critical current density: Measurements vs. reality

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    Different experimental techniques are employed to evaluate the critical current density (Jc), namely transport current measurements and two different magnetisation measurements forming quasi-equilibrium and dynamic critical states. Our technique-dependent results for superconducting YBa 2Cu3O7 (YBCO) film and MgB2 bulk samples show an extremely high sensitivity of Jc and associated interpretations, such as irreversibility fields and Kramer plots, which lose meaning without a universal approach. We propose such approach for YBCO films based on their unique pinning features. This approach allows us to accurately recalculate the magnetic-field-dependent Jc obtained by any technique into the Jc behaviour, which would have been measured by any other method without performing the corresponding experiments. We also discovered low-frequency-dependent phenomena, governing flux dynamics, but contradicting the considered ones in the literature. The understanding of these phenomena, relevant to applications with moving superconductors, can clarify their dramatic impact on the electric-field criterion through flux diffusivity and corresponding measurements. © Copyright EPLA, 2013

    Microcirculatory changes in travelers to a tropical country

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    Background Travelers to tropical areas seem to be affected by nonhealing leg ulcers more frequently. One of the factors that can affect wound healing in a negative manner is leg edema. This study was performed to determine whether there is increased leg edema in travelers to tropical areas. Method In this study, we measured the capillary filtration rate (CFR) of the lower leg by strain gauge plethysmography, as a measure of leg edema, on location in Surinam. Three groups were included: A, travelers in the first few weeks after arrival; 3, travelers who had stayed in the tropics for a minimum of 2 months; C, native inhabitants. Results The mean CFR (mL/100 mL tissue/min) was significantly higher in group A than in groups 3 and C; the difference between groups B and C was not significant (group A 0.05 mL/ 100 mL tissue/min (standard deviation (SD), 0,03) vs. group B 0.02 mL/100 mL tissue/min (SD, 0,02), F = 0.01, and vs. group C 0.02 mL/100 mL tissue/min (SD, 0.02), P = 0.01). Conclusions Travelers to tropical areas are affected by increased CFR in the first few weeks after arrival. A prolonged stay leads to the normalization of the CFR. Compression therapy is recommended for travelers to the tropic

    Epidemiology of cutaneous leishmaniasis in Suriname: a study performed in 2006

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    Cutaneous leishmaniasis (CL) is a widespread disease in Suriname caused by Leishmania Viannia guyanensis. It is argued that other Leishmania species are also responsible for CL and that the incidence is increasing. This study aimed to identify the species causing the disease and to estimate the annual detection rate of CL in Suriname in 2006. In Paramaribo, 152 patients were registered, of whom 33 were tested in two polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) methods. Twenty-seven patients were infected with L. (V.) guyanensis (complex), one with L. (V.) lainsoni, and one with L. (Leishmania) amazonensis. In the hinterland, 162 CL suspected patients were registered by questionnaires; of these, 24 of 27 tested positive by PCR-RFLP (88.9%; 95% CI, 77.1-100%). With extrapolation of collected data, a detection rate was calculated of 5.32 to 6.13 CL patients per 1,000 inhabitants for the hinterland and 0.64 to 0.74 patients per 1,000 inhabitants for the whole countr

    Case Report: First Case of Cutaneous Leishmaniasis Caused by Leishmania (Viannia) braziliensis in Suriname

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    The main causative agent of cutaneous leishmaniasis (CL) in Suriname is Leishmania (Viannia) guyanensis. This case report presents a patient infected with Leishmania (Viannia) braziliensis, a species never reported before in Suriname. This finding has clinical implications, because L. braziliensis has a distinct clinical phenotype characterized by mucocutaneous leishmaniasis, a more extensive and destructive form of CL that requires different treatment. Clinicians should be aware that chronic cutaneous ulcers in patients from the Guyana region could be caused by L. braziliensi
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