Reactive Oxygen Species in HaCaT Keratinocytes After UVB Irradiation Are Triggered by Intracellular Ca2+ Levels

It is recognized that reactive oxygen species (ROS) are responsible for skin damage due to UVB-radiation (UVB-R). However, the triggering substance(s) for ROS generation after UVB-R is uncertain with respect to the activation of NADPH oxidase (Nox), xanthine oxidase (XOD), and respiratory chain–chain reactions in mitochondria. As a first step in identifying the trigger(s) for UVB-induced ROS generation, we examined the relationship between Ca2+ levels and ROS generation in HaCaT keratinocytes. UVB-R exposure of HaCaT keratinocytes resulted in an immediate elevation of ROS that recurred 7 hours later. This was accompanied by immediately elevated intracellular Ca2+ . A Ca2+ chelating agent, BAPTA, abolished the elevation of ROS after UVB-R completely. In addition, exogenous H2O2 did not increase intracellular Ca2+ levels. This suggests that intracellular Ca2+ is the first trigger for UVB-induced ROS generation

Auroral O+ 732/733 nm emission and its relation to ion upflow

Observations of auroral oxygen ion emission at 732/733 nm were made at the Aurora station in Longyearbyen (78.2.N, 16.3.E; lm=74.9.) using an all-sky spectrograph (ASG) during the winter season of 2000/2001. A statistical analysis showed that the highest occurrence of oxygen ion auroras at Longyearbyen was seen in the dayside of the 09-12MLT region; the intensities of these auroras were also larger than those on the night side. To study the mechanism of ion up゜ow in the polar ionosphere, ASG data obtained on December 7, 2000, was analyzed together with simultaneous ionospheric data obtained by EISCAT Svalbard radar (ESR). Enhancements of electron temperature and ion upward velocity were associated with an increase in the auroral OII intensity at the magnetic zenith. This result suggests that an ambipolar electric field associated with electron temperature enhancement caused by soft electron precipitation may be involved in the mechanisms that drive ionospheric ions upward

A new meridian imaging spectrogarph for the auroral spectroscopy

Spectroscopic and monochromatic imaging observations of emissions in the upper atmosphere are mutually complementary. A meridian imaging auroral spectrograph (ASG) that can measure a spectrum in the visible region along a meridian has been developed for research on the auroral physics and the polar upper-atmosphere dynamics. Combination of a fast optical system inherited from a monochromatic all-sky imager, a grism as a dispersive element, and a cooled CCD camera has enabled a wide field-of-view of 180° along a meridian, spectral coverage of 420-730 nm, spectral resolution of 1.5-2.0 nm, and high sensitivity to be obtained. The absolute sensitivity over a full-image field was calibrated using a National Institute of Standards and Technology (NIST) traceable integrating sphere and determined to be 0.06 cts/s/R at a wavelength of 560 nm at the zenith. The ASG was installed at Longyearbyen in March 2000, and routine operation was started in the 2000/2001 winter season. An example of an auroral spectral image is presented in this report to demonstrate the performance of the ASG

Improved scientific ballooning applied to the cryo-sampling experiment at Syowa Station

On January 3, 1998, a large balloon (30000 m^3) was successfully launched at Syowa Station for the cryo-sampling of the stratospheric atmosphere. The sampling system splashed down in the Liitzow-Holm Bay and recovered by icebreaker SHIRASE. The cryo-sampling at Antarctica was the first trial in the world and the recovery of a heavy payload was also the first challenge at Syowa Station. A lot of new ballooning technologies were applied to this operation, such as compact balloon launching equipments, a reliable recovery system, a handy ground radio station for the balloon tracking and data acquisition and so forth. The realtime flight data could be received at National Institute of Polar Research (NIPR) in Tokyo by using the computer network via INMARSAT. At NIPR the collaboration members could monitor the entire process of the experiment at Syowa Station in detail and send some instructions and advice. This balloon experiment showed an extended possibility of a large scale scientific ballooning at Syowa Station. This paper deals with those newly developed balloon engineering technologies

Temporal and spatial variations of pulsating auroras in fine-scale obtained from ground-based observations

第2回極域科学シンポジウム/第35回極域宙空圏シンポジウム 11月16日（水） 統計数理研究所 3階リフレッシュフロ