30 research outputs found

    Electric instability in superconductor-normal conductor ring

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    Non-linear electrodynamics of a ring-shaped Andreev interferometer (superconductor-normal conductor-superconductor hybrid structure) inductively coupled to a circuit of the dissipative current is investigated. The current-voltage characteristics (CVC) is demonstrated to be a series of loops with several branches intersecting in the CVC origin. The sensitivity of the transport current to a change of the applied external magnetic flux can be comparable to the one of the conventional SQUID's. Spontaneous arising of coupled non-linear oscillations of the transport current, the Josephson current and the magnetic flux in Andreev interferometers are also predicted and investigated. The frequency of these oscillations can be varied in a wide range, while the maximal frequency can reach ωmax1012\omega_{max} \sim 10^{12} sec1sec^{-1}.Comment: 4 pages, 4 figure

    Nonambipolar Magnetic-Fluctuation-Induced Particle Transport and Plasma Flow in the MST Reversed-Field Pinch

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    First direct measurements of nonambipolar magnetic fluctuation-induced charge transport in the interior of a high-temperature plasma are reported. Global resistive tearing modes drive the charge transport which is measured in the vicinity of the resonant surface for the dominant core resonant mode. Finite charge transport has two important consequences. First, it generates a potential well along with locally strong electric field and electric field shear at the resonant surface. Second, this electric field induces a spontaneous E B driven zonal flow

    Examination of potential virulence factors of Candida tropicalis clinical isolates from hospitalized patients

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    Candida tropicalis has been reported to be one of the Candida species which is most likely to cause bloodstream and urinary tract infections in hospitalized patients. Accordingly, the aim of this study was to characterize the virulence of C. tropicalis by assessing antifungal susceptibility and comparing the expression of several virulence factors. This study was conducted with seven isolates of C. tropicalis from urine and blood cultures and from central venous catheter. C. tropicalis ATCC 750 was used as reference strain. Yeasts adhered (2 h) to epithelial cells and silicone and 24 h biofilm biomass were determined by crystal violet staining. Pseudohyphae formation ability was determined after growth in fetal bovine serum. Enzymes production (hemolysins, proteases, phospholipases) was assessed by halo formation on agar plates. Susceptibility to antifungal agents was determined by E-test. Regarding adhesion, it can be highlighted that C. tropicalis strains adhered significantly more to epithelium than to silicone. Furthermore, all C. tropicalis strains were able to form biofilms and to express total hemolytic activity. However, protease was only produced by two isolates from urine and by the isolates from catheter and blood. Moreover, only one C. tropicalis (from catheter) was phospholipase positive. All isolates were susceptible to voriconazole, fluconazole and amphotericin B. Four strains were susceptible-dose dependent to itraconazole and one clinical isolate was found to be resistant

    Lawson Criterion for Ignition Exceeded in an Inertial Fusion Experiment

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    Lawson criterion for ignition exceeded in an inertial fusion experiment

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    For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion

    A medium for inducing conversion of Histoplasma capsulatum var. capsulatum into its yeast-like form

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    Histoplasma capsulatum var. capsulatum is a dimorphic fungus that, under special conditions, converts from its more common mycelial form to a yeast-like form. Achieving this conversion, however, has been problematical for researchers. The present study tested conversion rates in ten Histoplasma capsulatum var. capsulatum strains using seven culture media, four of wich were conventional and three novel. One of our novel media, MLGema, induced complete conversion, of two strains within five days of incubation at 35 degrees centigrades, and of all strains that eventually converted by the time of the second subculturing transfer, under defined experimental conditions. MLGema is also inexpensive and easy to produce
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