The initiation and propagation of the early processes of bystander signaling induced by low-dose a-particle irradiation are very important for understanding the underlying mechanism of the bystander process. Our previous investigation showed that the medium collected from cell culture exposed to low-dose a-particle rapidly induced phosphorylated form of H2AX protein foci formation among the non-irradiated medium receptor cells in a timedependent manner. Using N G -methyl-L-arginine, 4-amino-5-methylamino-2 0 ,7 0 -difluorofluorescein diacetate and N xnitro-L-arginine (L-NNA) treatment before exposure to 1 cGy a-particle, we showed in the present study that nitric oxide (NO ) produced in the irradiated cells was important and necessary for the DNA double strand break inducing activity (DIA) of conditioned medium and the generation of NO in irradiated confluent AG1522 cells is in a time-dependent manner and that almost all NO was generated within 15 min post-irradiation. Concurrently, the kinetics of NO production in the medium of irradiated cells after irradiation was rapid and in a timedependent manner as well, with a maximum yield observed at 10 min after irradiation with electron spin resonance analysis. Furthermore, our results that 7-Nitroindazole and L-NNA, but not aminoguanidine hemisulfate, treatment before exposure to 1 cGy a-particle significantly decrease the DIA of the conditioned medium suggested that constitutive NO from the irradiated cells possibly acted as an intercellular signaling molecule to initiate and activate the early process (p30 min) of bystander response after low-dose irradiation.
The International Pulsar Timing Array 2nd data release is the combination of datasets from worldwide collaborations. In this study, we search for continuous waves: gravitational wave signals produced by individual supermassive black hole binaries in the local universe. We consider binaries on circular orbits and neglect the evolution of orbital frequency over the observational span. We find no evidence for such signals and set sky averaged 95% upper limits on their amplitude h95. The most sensitive frequency is 10nHz with h95 = 9.1 × 10−15. We achieved the best upper limit to date at low and high frequencies of the PTA band thanks to improved effective cadence of observations. In our analysis, we have taken into account the recently discovered common red noise process, which has an impact at low frequencies. We also find that the peculiar noise features present in some pulsars data must be taken into account to reduce the false alarm. We show that using custom noise models is essential in searching for continuous gravitational wave signals and setting the upper limit.
In a lower hybrid current drive experiment on the EAST tokamak in the spring of 2010, the process in which fast electrons transform into runaway electrons was observed, and the way in which lower hybrid waves (LHWs) affect the behavior of runaway electrons was studied. It was found that when the power of LHWs is below a certain threshold, fast electrons excited by LHWs can be accelerated to runaway electrons due to the primary generation mechanism of runaway electrons, but when the power is high enough, fast electrons cannot transform into runaway electrons anymore. No matter how high the power was, the production of runaway electrons due to the secondary generation mechanisms was suppressed.
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