Change in Edge Fluctuations Synchronized with Heat Pulse in the JFT-2M Tokamak

The change in edge fluctuations synchronized with a heat pulse during Sawtooth oscillation has been investigated inthe JFT-2M tokamak using a reciprocating Langmuir probe. Data window of a heat pulse is segmented into a number oftime frames, and time traces of auto-power spectra at each frame are calculated. Conditional averaging over a number ofheat pulse events in a single discharge is performed in order to reduce the variance of the fluctuation spectra. At eachheat pulse event, a reduction in the geodesic acoustic mode fluctuation power and an increase in the turbulencefluctuation power are observed. The change in the fluctuation powers suggests that the edge heat pulse during Sawtoothinstability could affect the edge turbulence structure

Cytotoxic, hepatoprotective and free radical scavenging effects of propolis from Brazil, Peru, the Netherlands and China

Propolis is a resinous hive product collected by honeybees from various plant sources. The composition of the propolis depends upon the time, vegetation and the area of collection. Thus, quality evaluation of the propolis is important, before use in food and beverages. For this propose three different biological activities were carried out, i.e. 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity, cytotoxicity and hepatoprotective activity, of MeOH and water extracts of nine different propolis from Brazil, Peru, the Netherlands and China. The results showed that water extracts of six Brazilian and a Chinese propolis possessed stronger DPPH free radical scavenging activity than the corresponding MeOH extract, whereas in the case of Netherlands and Peruvian propolis MeOH extract exhibited stronger DPPH free radical scavenging activity. The MeOH extracts of all propolis possessed stronger cytotoxicity than the corresponding water extract towards murine colon 26-L5 carcinoma and human HT-1080 fibrosarcoma cells. The result of hepatoprotective activity of Brazilian propolis on d-galactosamine (d-GalN)/tumor necrosis factor-\u3b1 (TNF-\u3b1)-induced cell death in primary cultured mouse hepatocytes were found in accordance with the grade set up by beekeepers in Brazil.Peer reviewed: YesNRC publication: N

Experimental Identification of Electric Field Excitation Mechanisms in a Structural Transition of Tokamak Plasmas

Self-regulation between structure and turbulence, which is a fundamental process in the complexsystem, has been widely regarded as one of the central issues in modern physics. A typical exampleof that in magnetically confined plasmas is the Low confinement mode to High confinement mode(L-H) transition, which is intensely studied for more than thirty years since it provides a confinementimprovement necessary for the realization of the fusion reactor. An essential issue in the L-H transitionphysics is the mechanism of the abrupt “radial” electric field generation in toroidal plasmas. To date,several models for the L-H transition have been proposed but the systematic experimental validationis still challenging. Here we report the systematic and quantitative model validations of the radialelectric field excitation mechanism for the first time, using a data set of the turbulence and the radialelectric field having a high spatiotemporal resolution. Examining time derivative of Poisson’s equation,the sum of the loss-cone loss current and the neoclassical bulk viscosity current is found to behave asthe experimentally observed radial current that excites the radial electric field within a few factors ofmagnitude