Efficacy of radiation countermeasures depends on radiation quality

The detonation of a nuclear weapon or a nuclear accident represent possible events with significant exposure to mixed neutron/γ-radiation fields. Although radiation countermeasures generally have been studied in subjects exposed to pure photons (γ or X rays), the mechanisms of injury of these low linear energy transfer (LET) radiations are different from those of high-LET radiation such as neutrons, and these differences may affect countermeasure efficacy. We compared 30-day survival in mice after varying doses of pure γ and mixed neutron/γ (mixed field) radiation (MF, Dn/Dt = 0.65), and also examined peripheral blood cells, bone marrow cell reconstitution, and cytokine expression. Mixed-field-irradiated mice displayed prolonged defects in T-cell populations compared to mice irradiated with pure γ photons. In mouse survival assays, the growth factor granulocyte colony-stimulating factor (G-CSF) was effective as a (post-irradiation) mitigator against both γ-photons and mixed-field radiation, while the thrombopoietin (TPO) mimetic ALXN4100TPO was effective only against γ irradiation. The results indicate that radiation countermeasures should be tested against radiation qualities appropriate for specific scenarios before inclusion in response plans.     

Review: Weak radiofrequency radiation exposure from mobile phone radiation on plants

Aim: The aim of this article was to explore the hypothesis that non-thermal, weak, radiofrequency electromagnetic fields (RF-EMF) have an effect on living plants. Subject and methods: In this study, we performed an analysis of the data extracted from the 45 peer-reviewed scientific publications (1996–2016) describing 169 experimental observations to detect the physiological and morphological changes in plants due to the non-thermal RF-EMF effects from mobile phone radiation. Twenty-nine different species of plants were considered in this work. Results: Our analysis demonstrates that the data from a substantial amount of the studies on RF-EMFs from mobile phones show physiological and/or morphological effects (89.9%, p < 0.001). Additionally, our analysis of the results from these reported studies demonstrates that the maize, roselle, pea, fenugreek, duckweeds, tomato, onions and mungbean plants seem to be very sensitive to RF-EMFs. Our findings also suggest that plants seem to be more responsive to certain frequencies, especially the frequencies between (i) 800 and 1500 MHz (p < 0.0001), (ii) 1500 and 2400 MHz (p < 0.0001) and (iii) 3500 and 8000 MHz (p = 0.0161). Conclusion: The available literature on the effect of RF-EMFs on plants to date observed the significant trend of radiofrequency radiation influence on plants. Hence, this study provides new evidence supporting our hypothesis. Nonetheless, this endorses the need for more experiments to observe the effects of RF-EMFs, especially for the longer exposure durations, using the whole organisms. The above observation agrees with our earlier study, in that it supported that it is not a well-grounded method to characterize biological effects without considering the exposure duration. Nevertheless, none of these findings can be directly associated with human; however, on the other hand, this cannot be excluded, as it can impact the human welfare and health, either directly or indirectly, due to their complexity and varied effects (calcium metabolism, stress proteins, etc.). This study should be useful as a reference for researchers conducting epidemiological studies and the long-term experiments, using whole organisms, to observe the effects of RF-EMFs.     

Effects of far-infrared radiation on lactation

Massage and warm compresses to the breast have been commonly used for stimulating and/or increasing blood flow to the breasts, and for enhancing lactation consequently. However, more effective and easier remedies seem to be necessary. The vasodilating and warming effects of ceramics far-infrared radiation were studied. Based on the results obtained, the effect of a ceramic disc on lactation, attached to the breast skin, was evaluated in 27 puerperal women who had had poor lactation previously and in 36 with currently poor lactation monthly until weaning. Approximately 3/4 of these puerperal women enhanced lactation significantly one month after attachment and 1/2 of the women were able to breast-feed until weaning. Thus, we found that ceramics far-infrared radiation may be an effective remedy for enhancing lactation.     

Effects of ionizing radiation on mitochondria

The current concept of radiobiology posits that damage to the DNA in the cell nucleus is the primary cause for the detrimental effects of radiation. However, emerging experimental evidence suggests that this theoretical framework is insufficient for describing extranuclear radiation effects, particularly the response of the mitochondria, an important site of extranuclear, coding DNA. Here, we discuss experimental observations of the effects of ionizing radiation on the mitochondria at (1) the DNA and (2) functional levels. The roles of mitochondria in (3) oxidative stress and (4) late radiation effects are discussed. In this review, we summarize the current understanding of targets for ionizing radiation outside the cell nucleus. Available experimental data suggest that an increase in the tumoricidal efficacy of radiation therapy might be achievable by targeting mitochondria. Likewise, more specific protection of mitochondria and its coding DNA should reduce damage to healthy cells exposed to ionizing radiation.     

Potential solar radiation on plant shapes

The thesis is presented that most plant-shapes, especially trees, resemble a combination of geometrical shapes which present their non-opaque bodies to incoming radiation, which is partially absorbed by the foliage. Such a hypothesis makes possible the quantification of the budget of energy of the entire plant. This first report presents only the findings in regard to the receipt of direct and diffuse solar radiation from the sky (clear conditions), before reflection and absorption, on a variety of geometries which simulate common plant-shapes. An all-year simulation of potential insolation for such shapes was conducted for latitudes 0° to 90°. Each shape, latitude and each season exhibited its own characteristic patterns of the various energy cycles. Derived data differed materially from data applicable to horizontal surfaces. The simulated plant-shapes tended to avoid receipt of energy in the low latitudes, whereas the opposite occurred toward higher latitudes.

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Zusammenfassung Die meisten Pflanzenumrisse, speziell Bäume, ähneln einer Kombination geometrischer Formen. Die Bäume sind nicht-undurchsichtige Körper für einkommende Strahlung, die durch die Blätter teilweise absorbiert wird. Nach der Hypothese ist es möglich, den Energiehaushalt für die gesamte Pflanze zu quantifizieren. Dieser erste Bericht befasst sich nur mit den Ergebnissen der direkten und diffusen Sonnenstrahlung vom Himmel bei klaren Bedingungen vor Reflexion und Absorption bei einer Anzahl simulierter geometrischer Formen, die auf allgemeinen Pflanzenumrissen basieren. Eine ganzjährige Simulation der potentiellen Besonnung dieser Formen wurde für alle Breiten von 0° bis 90° berechnet. Jede Form, Breite und Jahreszeit zeigt ihre eigenen charakteristischen Verläufe der verschiedenen Energiezyklen. Die abgeleiteten Werte unterscheiden sich von den Werten, die auf horizontale Oberflächen anwendbar sind. Die simulierten Pflanzenkörper neigten zur Vermeidung von Energieaufnahme in niedrigen Breiten, während bei höheren Breiten das Umgekehrte auftrat.

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Resume Les formes extérieures des plantes et plus spécialement celles des arbres peuvent se ramener à des combinaisons de formes géométriques. Les arbres ne constituent pas des corps opaques pour le rayonnement, mais celuici n'est que partiellement absorbé par la couronne. Selon l'hypothèse présentée ici, il est possible de déterminer quantitativement le bilan énergétique de la plante entière. Ce premier mémoire se restreint à l'étude de l'absorption du rayonnement direct et diffus, c'est-à-dire du soleil et d'un ciel serein. Ces résultats sont calculés avant toute réflexion ou absorption par d'autres corps et se rapportent à un certain nombre de formes géométriques simulant des profils typiques d'arbres. On a ainsi calculé le gain énergétique de ces formes pour toute l'année et pour toutes les latitudes de 0° à 90°. Chaque profil, chaque latitude et chaque saison présente des caractéristiques propres quant à l'évolution des différents cycles d'énergie. Les valeurs ainsi obtenues se distinguent nettement de valeurs correspondantes se rapportant à des surfaces horizontales. Les profils de plantes examinés tendent à absorber aussi peu d'énergie que possible dans les basses latitudes, alors que c'est le contraire qui se produit au voisinage des pôles.

     

Effects of nonionizing radiation on birds

1. With the ability to fly comes a greater probability of direct irradiation by nonionizing radiation. The effect of nonionizing radiation on birds is, therefore, of environmental significance. 2. Most biological effects of exposure to nonionizing radiation in avian species are a result of radiation-induced temperature increases. 3. The incubating avian egg provides a model to study nonthermal effects of microwave exposure since ambient incubation temperature can be adjusted to compensate for absorbed thermal energy. 4. Some studies have shown that exposure to nonthermal levels of nonionizing radiation affect a bird's ability to recover from acute physiological stressors. 5. Although earlier research indicated that modulated radiofrequency radiation increased calcium-ion efflux in chick forebrain tissue, criticism of experimental techniques and contradictory results between related studies have made final conclusions elusive. 6. Birds have been shown to be able to reliably detect magnetic fields in both the field and laboratory. Some researchers have reported malformations in chicken embryos exposed to a sinusoidal bipolar oscillating magnetic field.     

Effects of radiation on the environment: a need to question old paradigms and enhance collaboration among radiation biologists and radiation ecologists

A historical perspective is given of the current paradigm that does not explicitly protect nonhuman biota from radiation but instead relies on the concept that if dose limits are set to protect humans, then the environment is automatically protected as well. We summarize recent international questioning of this paradigm and briefly present three frameworks for protecting biota that are being considered by the U.S. Department of Energy, the Canadian Nuclear Safety Commission, and the International Commission on Radiological Protection. We point out a controversial component in each of the three frameworks and suggest topics that need additional research. We emphasize that to properly address radiation protection of the environment, we need to understand how effects are integrated across different levels of biological organization. We caution that the proposed use of molecular end points to estimate ecological risks from radioactive contamination is applicable only if we understand the extent of the impact that molecular damage has on individual organisms and populations of exposed biota. To accomplish the latter, enhanced collaborations are required among the traditionally separate disciplines of radiation biology and radiation ecology.     

Effect of physiological age on radiation resistance of some bacteria that are highly radiation resistant

Physiological age-dependent variation in radiation resistance was studied for three bacteria that are highly radiation resistant: Micrococcus radiodurans, Micrococcus sp. isolate C-3, and Moraxella sp. isolate 4. Stationary-phase cultures of M. radiodurans and isolate C-3 were much more resistant to gamma radiation than were log-phase cultures. This pattern of relative resistance was reversed for isolate 4. Resistance of isolate 4 to UV light was also greater during log phase, although heat resistance and NaCl tolerance after heat stress were greater during stationary phase. Radiation-induced injury of isolate 4 compared with injury of Escherichia coli B suggested that the injury process, as well as the lethal process, was affected by growth phase. The hypothesis that growth rate affects radiation resistance was tested, and results were interpreted in light of the probable confounding effect of methods used to alter growth rates of bacteria. These results indicate that dose-response experiments should be designed to measure survival during the most resistant growth phase of the organism under study. This timing is particularly important when extrapolations of survival results might be made to potential irradiation processes for foods.     

Gamma radiation effects on fruits and vegetables

Several million dollars are lost in the United States each year as a result of post harvest diseases of crops. Claim costs to railroads alone in 1958 amounted to $11 million. This work demonstrates that it is possible to extend the shelf-life of fresh fruits and vegetables at room as well as at refrigeration temperatures by gamma radiation, by surface pasteurization, sprout inhibition, and also by retarding the ripening processes. The information presented should be useful to researchers, shippers, packers, and processors.