High atomic number and high-energy (HZE) particles in deep space are of low abundance but substantially contribute to the biological effects of space radiation. Shielding is so far the most effective way to partially protect astronauts from these highly penetrating particles. However, simulated calculations and measurements have predicted that secondary particles resulting from the shielding of...

The assumption of a linear dose response used to describe the biological effects of high-LET radiation is fundamental in radiation protection methodologies. We investigated the dose response for chromosomal aberrations for exposures corresponding to less than one particle traversal per cell nucleus by high-energy charged (HZE) nuclei. Human fibroblast and lymphocyte cells were irradiated with s...

During interplanetary missions, astronauts are exposed to mixed types of ionizing radiation. The low 'flux' of the high atomic number and high energy (HZE) radiations relative to the higher 'flux' of low linear energy transfer (LET) protons makes it highly probable that for any given cell in the body, proton events will precede any HZE event. Whereas progress has been made in our understanding ...

The role of DNA repair by nonhomologous end joining (NHEJ), homologous recombination, spore photoproduct lyase, and DNA polymerase I and genome protection via alpha/beta-type small, acid-soluble spore proteins (SASP) in Bacillus subtilis spore resistance to accelerated heavy ions (high-energy charged [HZE] particles) and X rays has been studied. Spores deficient in NHEJ and alpha/beta-type SASP...

In deep space astronauts are usually exposed to doses of ~ 1 mSv/day of charged particles, including HZE. Due to the exposure to GCR (e.g. during a mission to Mars), each cell nucleus of an astronaut would be traversed by a proton or by a secondary electron every few days, but only by an HZE ion every few months [1]. For this reason, besides the clustered properties of the incoming radiation on...

Rats exposed to 0.1-5 Gy of heavy particles (56Fe, 40Ar, 20Ne or 4He) showed dose-dependent changes in body temperature. Lower doses of all particles produced hyperthermia, and higher doses of 20Ne and 56Fe produced hypothermia. Of the four HZE particles, 56Fe particles were the most potent and 4He particles were the least potent in producing changes in thermoregulation. The 20Ne and 40Ar parti...

One of the major health risks to astronauts is radiation on long-duration space missions. Space radiation from sun and galactic cosmic rays consists primarily of 85% protons, 14% helium nuclei and 1% high-energy high-charge (HZE) particles, such as oxygen (16O), carbon, silicon, and iron ions. HZE particles exhibit dense linear tracks of ionization associated with clustered DNA damage and often...

The radiation environments of space cannot be replicated on earth and the biological consequences of this exposure cannot be evaluated through human experience. As a result, organizations like NASA or DOE have no choice but to evaluate radiation risks through experiments performed on laboratory animals. Laboratory animals die from many of the same causes as humans, but they also die from their ...

The induction of nontargeted stressful effects in cell populations exposed to low fluences of high charge (Z) and high energy (E) particles is relevant to estimates of the health risks of space radiation. We investigated the up-regulation of stress markers in confluent normal human fibroblast cultures exposed to 1,000 MeV/u iron ions [linear energy transfer (LET) ∼151 keV/μm] or 600 MeV/u silic...