873 research outputs found

    Einfluss des zuckerfreien Kaugummikauens bei Prothesenträgern mit Mundtrockenheit auf die Mundgesundheit und die Lebensqualität

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    Insgesamt nahmen 121 Probanden beiderlei Geschlechts mit einem Durchschnittsalter von 65,6 Jahren an dieser Studie teil.In der Anfangsuntersuchung wurde eine Befunderhebung durchgeführt.Bei allen Probanden wurde die Gesamtruhespeichel- und die stimulierte Gesamtspeichelfließrate gemessen und der pH-Wert bestimmt. Die Probenden wurden in eine Kontroll- und eine Kaugruppe,unterteilt. Nach Abschluss der Stimulationshase wurden alle genannten Parameter neu erhoben.Auf der Basis der in dieser Studie gewonnenen Daten kann der regelmäßige Gebrauch von zuckerfreien Kaugummiprodukten als wirkungsvolle Maßnahme zur Überwindung der Mundtrockenheitssymptomatik und der damit verbundenen Erhöhung der Mundgesundheit zum einen, der Verbesserung des Prothesensitzes und der Lebensqualität zum anderen empfohlen werden

    Demonstration of a beam loaded nanocoulomb-class laser wakefield accelerator.

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    Laser-plasma wakefield accelerators have seen tremendous progress, now capable of producing quasi-monoenergetic electron beams in the GeV energy range with few-femtoseconds bunch duration. Scaling these accelerators to the nanocoulomb range would yield hundreds of kiloamperes peak current and stimulate the next generation of radiation sources covering high-field THz, high-brightness X-ray and γ-ray sources, compact free-electron lasers and laboratory-size beam-driven plasma accelerators. However, accelerators generating such currents operate in the beam loading regime where the accelerating field is strongly modified by the self-fields of the injected bunch, potentially deteriorating key beam parameters. Here we demonstrate that, if appropriately controlled, the beam loading effect can be employed to improve the accelerator's performance. Self-truncated ionization injection enables loading of unprecedented charges of ∼0.5 nC within a mono-energetic peak. As the energy balance is reached, we show that the accelerator operates at the theoretically predicted optimal loading condition and the final energy spread is minimized.Higher beam quality and stability are desired in laser-plasma accelerators for their applications in compact light sources. Here the authors demonstrate in laser plasma wakefield electron acceleration that the beam loading effect can be employed to improve beam quality by controlling the beam charge

    On Shape Transformations and Shape Fluctuations of Cellular Compartments and Vesicles

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    We discuss the shape formation and shape transitions of simple bilayer vesicles in context with their role in biology. In the first part several classes of shape changes of vesicles of one lipid component are described and it is shown that these can be explained in terms of the bending energy concept in particular augmented by the bilayer coupling hypothesis. In the second part shape changes and vesicle fission of vesicles composed of membranes of lipid mixtures are reported. These are explained in terms of coupling between local curvature and phase separation

    Periodically kicked turbulence

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    Periodically kicked turbulence is theoretically analyzed within a mean field theory. For large enough kicking strength A and kicking frequency f the Reynolds number grows exponentially and then runs into some saturation. The saturation level can be calculated analytically; different regimes can be observed. For large enough Re we find the saturation level to be proportional to A*f, but intermittency can modify this scaling law. We suggest an experimental realization of periodically kicked turbulence to study the different regimes we theoretically predict and thus to better understand the effect of forcing on fully developed turbulence.Comment: 4 pages, 3 figures. Phys. Rev. E., in pres
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