Gender differences in DNA damage/repair after laser-generated ultrafast electron beam irradiation
The laser-generated electron acceleration is a developing technology, which can make a revolution in radiation therapy of tumors. The possibility of creating directed ultra-short pulses of enormous capacity (up to kGy/s) allows the precise dose-control induction of local effects on solid tumors with minimal exposure of normal tissues. The obvious advantage of laser-generated electron accelerators is also the significantly smaller size and cost than that of conventional radiotherapy machines.1 There are only a few publications on the biological effects of ultra-short pulsed electron beam radiation.2–5 However, before translating the usage of lasergenerated accelerators into clinical practice, the radiobiological effectiveness of such ultra-short electron bunches should be approved.
Low-Energy Laser-Driven Ultrashort Pulsed Electron Beam Irradiation-Induced Immune Response in Rats
The development of new laser-driven electron linear accelerators, providing unique ultrashort pulsed electron beams (UPEBs) with low repetition rates, opens new opportunities for radiotherapy and new fronts for radiobiological research in general. Considering the growing interest in the application of UPEBs in radiation biology and medicine, the aim of this study was to reveal the changes in immune system in response to low-energy laser-driven UPEB whole-body irradiation in rodents. Forty male albino Wistar rats were exposed to laser-driven UPEB irradiation, after which different immunological parameters were studied on the 1st, 3rd, 7th, 14th, and 28th day after irradiation. According to the results, this type of irradiation induces alterations in the rat immune system, particularly by increasing the production of pro- and anti-inflammatory cytokines and elevating the DNA damage rate. Moreover, such an immune response reaches its maximal levels on the third day after laser-driven UPEB whole-body irradiation, showing partial recovery on subsequent days with a total recovery on the 28th day. The results of this study provide valuable insight into the effect of laser-driven UPEB whole-body irradiation on the immune system of the animals and support further animal experiments on the role of this novel type of irradiation.
FORTE observations of lightning radio‐frequency signatures: Capabilities and basic results
The FORTE satellite, launched on August 29, 1997, carries both radio‐frequency‐receiver and optical (imaging and photometric) payloads for the study of lightning. The radio‐frequency (RF) data for the first 7 months of operation are described, both to illustrate the satellite's capabilities and to explain the basic statistical findings so far. FORTE's multichannel RF trigger system represents a significant advance in space‐based monitoring of lightning emissions. We are able to observe even rather weak and diffuse RF emissions from lightning and are no longer limited to the brightest known events, “transionospheric pulse pairs,” or TIPPs. We do see TIPPs, and we show that the FORTE observations of TIPPs are consistent only with the second pulse's being due to a ground reflection. We find that TIPPs are basically bimodal in character, one type having a steep roll‐off of power from 38 to 130 MHz and the other being essentially flat‐spectrum in that range. The steep‐spectrum TIPPs cluster together in the manner of most RF emissions from lightning, while the flat‐spectrum events tend to maintain a wider spacing (>0.1 s) between recurrent emissions.