A possibility to predict the severity of individual damage following the exposure to supralethal radiation dosage. Prediction of the clinical manifestation of radiation injury in laboratory animals by response to pre-exposure hypobaric hypoxia

The experiments on rats, dogs and monkeys exposed to radiation doses which cause intestinal and cerebral forms of radiation sickness have shown that the severity of a clinical state can be predicted by cardiovascular and endocrine changes when a pre-exposure test with moderate hypobaric hypoxia is performed. The goodness of fit of experimental data to the exposed result is up to 60-80%, still rising if a set of indices of the neuroendocrine status is used.     

A possibility to predict the severity of individual damage following the exposure to supralethal radiation dosage. Prediction of working capacity of irradiated rats and dogs by response to pre-exposure hypobaric load

In experiments on rats and dogs exposed to radiation doses which cause intestinal and cerebral forms of radiation sickness, hypobaric hypoxia used as an unconventional test of animals' reactivity has enabled the relationship between reactivity and radiosensitivity to be established. Higher post-radiation efficiency is observed in animals with less pronounced changes during a barotest. The goodness of fit of experimental data to the expected result is up to 70%, rising if a set parameters for one index or the sum total of indices are used.     

Comparison of UTCI to selected thermal indices

Over the past century more than 100 indices have been developed and used to assess bioclimatic conditions for human beings. The majority of these indices are used sporadically or for specific purposes. Some are based on generalized results of measurements (wind chill, cooling power, wet bulb temperature) and some on the empirically observed reactions of the human body to thermal stress (physiological strain, effective temperature). Those indices that are based on human heat balance considerations are referred to as "rational indices". Several simple human heat balance models are known and are used in research and practice. This paper presents a comparative analysis of the newly developed Universal Thermal Climate Index (UTCI), and some of the more prevalent thermal indices. The analysis is based on three groups of data: global data-set, synoptic datasets from Europe, and local scale data from special measurement campaigns of COST Action 730. We found the present indices to express bioclimatic conditions reasonably only under specific meteorological situations, while the UTCI represents specific climates, weather, and locations much better. Furthermore, similar to the human body, the UTCI is very sensitive to changes in ambient stimuli: temperature, solar radiation, wind and humidity. UTCI depicts temporal variability of thermal conditions better than other indices. The UTCI scale is able to express even slight differences in the intensity of meteorological stimuli.     

The intensity of proteolysis in the peripheral blood lymphocytes of rats in the early period of acute radiation injury

Comparative analysis of biochemical indices that reflect the proteolysis rate in rat peripheral blood lymphocytes in normal conditions and during the first 4-6 h after whole-body single uniform gamma-irradiation with lethal (7.5 Gy) and nonlethal (3 Gy) doses has revealed that the pronounced activation of proteolysis in lymphocytes and the disturbances in the inhibitor/protease balance are characteristic of the severe form of radiation damage with fatal outcome. Simultaneously changes occur in biochemical indices of plasma that reflect a catabolic pathway of metabolism in the whole-body. The absence of similar changes in the blood of the survived animals permits to recommend the biochemical indices under study to be used for early prognosis of the radiation affection outcome.     

Estimation of the contribution of the dose rate to the effect of whole body uniform irradiation with 1000 MeV protons

Some biochemical indices of peripheral blood and spleen and the survival rate of albino rats after whole-body uniform irradiation with 1000 MeV protons delivered in two ways have been studied. The data obtained indicate that the dose rate contributes to the biological effect of impulse proton radiation.     

Content of blood lipids and characteristics of dyslipoproteinemias in people exposed to radiation during the accident at the Chernobyl nuclear power station

Lipid and lipoprotein spectrum of the blood plasma was investigated and phenotyping of hyperlipoproteinaemias was carried out in men exposed to ionizing radiation and suffered from acute radiation illness as a result of the Chernobyl accident. An increase of the total cholesterol triglycerides and content frequency of atherogenic types of hyperlipoproteinaemias in comparison with average levels of population both a year and 3 years after irradiation was observed. No essential differences were found between the obtained indices 1 and 3 years after irradiation which testified to the stability of the revealed disturbances.     

Chromosome damage and micronucleus formation in human blood lymphocytes exposed in vitro to radiofrequency radiation at a cellular telephone frequency (847.74 MHz, CDMA)

Peripheral blood samples collected from four healthy nonsmoking human volunteers were diluted with tissue culture medium and exposed in vitro for 24 h to 847.74 MHz radiofrequency (RF) radiation (continuous wave), a frequency employed for cellular telephone communications. A code division multiple access (CDMA) technology was used with a nominal net forward power of 75 W and a nominal power density of 950 W/m(2) (95 mW/cm(2)). The mean specific absorption rate (SAR) was 4.9 or 5.5 W/kg. Blood aliquots that were sham-exposed or exposed in vitro to an acute dose of 1.5 Gy of gamma radiation were included in the study as controls. The temperatures of the medium during RF-radiation and sham exposures in the Radial Transmission Line facility were controlled at 37 +/- 0.3 degrees C. Immediately after the exposures, lymphocytes were cultured at 37 +/- 1 degrees C for 48 or 72 h. The extent of genetic damage was assessed from the incidence of chromosome aberrations and micronuclei. The kinetics of cell proliferation was determined from the mitotic indices in 48-h cultures and from the incidence of binucleate cells in 72-h cultures. The data indicated no significant differences between RF-radiation-exposed and sham-exposed lymphocytes with respect to mitotic indices, frequencies of exchange aberrations, excess fragments, binucleate cells, and micronuclei. The response of gamma-irradiated lymphocytes was significantly different from that of both RF-radiation-exposed and sham-exposed cells for all of these indices. Thus there was no evidence for induction of chromosome aberrations and micronuclei in human blood lymphocytes exposed in vitro for 24 h to 847.74 MHz RF radiation (CDMA) at SARs of 4.9 or 5.5 W/kg.     

Correlation between the complex of body reactions to exposure to acute hypoxia and individual radiosensitivity in irradiation at a dose of 200 Gr

A study was made of a correlation between the response of basal metabolism to acute hypoxia and the life span of rats after irradiation resulting in the development of a cerebral form of radiation sickness. The more radiosensitive animals consumed a larger amount of oxygen, exhaled a lesser amount of carbon dioxide, and showed an increased normal expiratory exchange per minute. After the effect of acute hypoxia all the indices under study exhibited an opposite picture.     

A comparative analysis of the impact on biota and man in the 30 km zone of the Chernobyl NPP

A methodological approach is described for a comparative assessment of ionizing radiation effects on man and biota, based on the use of indices of radiation impact--ratios of actual exposure doses to environmental objects (including humans) and critical ones. As such doses, standards limiting radiation exposure and doses at which phenotypical effects were absent after the Chernobyl accident were employed, respectively for man and biota. For the test site chosen within the 30 km ChNPP zone (region of the Borshchovka settlement), dose burdens to reference biota species and the population (with and without evacuation) and the corresponding radiation impact indices were calculated. For the long term period after the accident radiation safety standards for man are shown to ensure radiation safety for biota as well. At the same time in the early period after the accident the emergency regulations do not guarantee adequate protection of nature, some species of which can be subject to irradiation more than man, even if countermeasures like evacuation are not applied. A conclusion has been made on the necessity of a more detailed and comprehensive analysis of situations when the anthropocentric principle "if radiation standards protect man then biota are also adequately protected" is violated.     

Assessing the effect of solar radiation on plant salt tolerance as defined by the static and dynamic indices

Any interaction between plant salt tolerance and environment is critical to crop breeders, geneticists, molecular biologists, soil-water-crop modelers and all researchers interested in 'global change'. A common criterion used for plant salt tolerance is a threshold value of root zone salinity, a static index that delimits the onset of yield reduction. According to this criterion, it was discovered that tomato salt tolerance decreases significantly with reduced solar radiation. In contrast, the threshold values of a new index based on the dynamic processes of salt accumulation relative to growth, are invariant to solar radiation. The variability and stability of the respective indices provides new insights for accessing physical and biochemical processes governing plant response in saline environments.     

不同剂量UV-B辐射对冬小麦幼苗形态及生理指标的影响

UV-B辐射增强对植物的影响效果存在差异,即使是同一物种的不同品种之间也存在差异。本研究以对UV-B不同耐性的2个冬小麦品种科遗26和泰山269为材料,比较了品种间及UV-B的剂量间的形态指标、生物量及生理指标的差异。结果表明:高剂量UV-B处理抑制了株高、叶色、茎数、鲜质量、光反应系统Ⅱ(PSⅡ)最大光化学效率(Fv/Fm)和光合速率,促进了丙二醛、类黄酮含量的增加及相对电导率的提高,2个品种的趋势基本相同,但泰山269的变化幅度大于科遗26,说明泰山269比科遗26敏感;低剂量的UV-B对株高、叶色、茎数、鲜质量表现出促进的趋势,对类黄酮的促进作用较大,对Fv/Fm、丙二醛及相对电导率的影响相对较小。     

Participation of the lipid peroxidation processes in the adaptation mechanism of Muridae like rodents to the radioactive contamination of the Chernobyl NPP zone

Results of the comparative analysis of the complex investigation of rodent population state caught at areas with different levels of contamination in the accident zone of the Chernobyl NPP during 1986-1993 and 2007, at areas with a practically normal radiation background in the neighborhood of the Kiev City in 1993 and at areas with the normal and increased radiation background in Ukhta region of Komi Republic in 1993-2008 are presented. It is shown that the absence of the linear dependence in changes of the lipid peroxidation (LPO) regulatory system parameters in rodent tissues on the dose of the external gamma-radiation at areas of their trap persists for a long time. Different ability to normalization of the studied indices and nonlinearity of their dose dependences allow us to suggest that changes of the scale and direction of interrelations between the reciprocal parameters of the LPO regulatory system in norm in tissues of rodents which were caught in the accident zone and at areas with an increased radiation background should be the information signal determining selection of the strategy of adaptation to the chronic radiation factor action.     

Prematurely condensed chromosome fragments in human lymphocytes induced by high doses of high-linear-energy-transfer irradiation

This study provides a useful biodosimetry protocol for radiation accidents that involve high doses of heavy particle radiation. Human peripheral blood lymphocytes (PBLs) were irradiated in vitro with high doses (5–50 Gy) of charged heavy-ion particles (carbon ions, at an effective linear-energy-transfer (LET) of 34.6 keV/μm), and were then stimulated to obtain dividing cells. PBLs were treated with 100 nM calyculin A to force chromosomes to condense prematurely, and chromosome spreads were obtained and stained with Giemsa. The G2 prematurely condensed chromosome (G2-PCC) index and the number of G2-PCC including fragments (G2-PCC-Fs) per cell for each radiation dose point were scored. Dose-effect relationships were obtained by plotting the G2-PCC indices or G2-PCC-Fs numbers against radiation doses. The G2-PCC index was greater than 5% up to doses of 15 Gy; even after a 30 Gy radiation dose, the index was 1 to 2%. At doses higher than 30 Gy, however, the G2-PCC indices were close to zero. The number of G2-PCC-Fs increased steeply for radiation doses up to 30 Gy at a rate of 1.07 Gy⁻¹. At doses higher than 30 Gy, the numbers of G2-PCC-Fs could not be accurately indexed because of the limited numbers of cells for analysis. Therefore, the number of G2-PCC-Fs could be used to estimate radiation doses up to 30 Gy. In addition, a G2-PCC index close to zero could be used as an indicator for radiation doses greater than 40 Gy.     

Modelling radiation fluxes in simple and complex environments: basics of the RayMan model

Short- and long-wave radiation flux densities absorbed by people have a significant influence on their energy balance. The heat effect of the absorbed radiation flux densities is parameterised by the mean radiant temperature. This paper presents the physical basis of the RayMan model, which simulates the short- and long-wave radiation flux densities from the three-dimensional surroundings in simple and complex environments. RayMan has the character of a freely available radiation and human-bioclimate model. The aim of the RayMan model is to calculate radiation flux densities, sunshine duration, shadow spaces and thermo-physiologically relevant assessment indices using only a limited number of meteorological and other input data. A comparison between measured and simulated values for global radiation and mean radiant temperature shows that the simulated data closely resemble measured data.     

Multivariate statistical analysis of tissue basophils in acute radiation sickness

By means of mark scale estimation method, discriminant and factor analyses, changes in integral indices on the state of mast cells in the rat mesentery have been investigated in dynamics of medullary, intestinal and cerebral forms of an acute radiation sickness. The integral indices are calculated basing on the morphometric parameters of the cells, that are obtained after the histological preparations are treated in a special automatic system for analysing images. At the medullary form of the acute radiation sickness, the greatest structural rearrangements of the mast cells take place during the first hours after the radiation, as well as during the climax of the disease, at the intestinal form, the analogous changes are revealed 1-3 days after the effect, and at the cerebral form--3 h after the radiation. The integral indices, calculated by means of the three methods, are well correlated with each other.     

Experimental and theoretical investigations on the validity of the geometrical optics model for calculating the stability of optical traps.

We have developed a computer program based on the geometrical optics approach proposed by Roosen to calculate the forces on dielectric spheres in focused laser beams. We have explicitly taken into account the polarization of the laser light and thd divergence of the laser beam. The model can be used to evaluate the stability of optical traps in a variety of different optical configurations. Our calculations explain the experimental observation by Ashkin that a stable single-beam optical trap, without the help of the gravitation force, can be obtained with a strongly divergent laser beam. Our calculations also predict a different trap stability in the directions orthogonal and parallel to the polarization direction of the incident light. Different experimental methods were used to test the predictions of the model for the gravity trap. A new method for measuring the radiation force along the beam axis in both the stable and instable regions is presented. Measurements of the radiation force on polystyrene spheres with diameters of 7.5 and 32 microns in a TEM00-mode laser beam showed a good qualitative correlation with the predictions and a slight quantitative difference. The validity of the geometrical approximations involved in the model will be discussed for spheres of different sizes and refractive indices.     

辽东栎冠层光合生理特性的空间异质性

冠层作为林木与环境因子相互作用最为直接的部分,研究冠层光合作用是分析森林生产力的基础。以北京东灵山辽东栎为对象,利用Li-6400便携式光合仪测定了不同冠层不同方向部位叶片的光合速率和光响应曲线,研究了叶片光合生理特性在冠层空间上的变化。结果表明：在不同冠层和不同方向上,饱和光合速率、光补偿点、光下暗呼吸和表观量子效率均存在差异,随着冠层下降以及从南至北,大多数光合生理特性指标表现出递减趋势。进一步的通径分析结果得出,光强、水气压亏缺、温度是影响不同层次光合速率的主要因子。冠层光合特性的空间异质性研究,对于在冠层水平上揭示植物固碳能力和估算植物生产力具有很重要的意义。     

The use of specialisation indices to predict vulnerability of coral‐feeding butterflyfishes to environmental change

In the absence of detailed assessments of extinction risk, ecological specialisation is often used as a proxy of vulnerability to environmental disturbances and extinction risk. Numerous indices can be used to estimate specialisation; however, the utility of these different indices to predict vulnerability to future environmental change is unknown. Here we compare the performance of specialisation indices using coral‐feeding butterflyfishes as a model group. Our aims were to 1) quantify the dietary preferences of three butterflyfish species across habitats with differing levels of resource availability; 2) investigate how estimates of dietary specialisation vary with the use of different specialisation indices; 3) determine which specialisation indices best inform predictions of vulnerability to environmental change; and 4) assess the utility of resource selection functions to inform predictions of vulnerability to environmental change. The relative level of dietary specialisation estimated for all three species varied when different specialisation indices were used, indicating that the choice of index can have a considerable impact upon estimates of specialisation. Specialisation indices that do not consider resource abundance may fail to distinguish species that primarily use common resources from species that actively target resources disproportionately more than they are available. Resource selection functions provided the greatest insights into the potential response of species to changes in resource availability. Examination of resource selection functions, in addition to specialisation indices, indicated that Chaetodon trifascialis was the most specialised feeder, with highly conserved dietary preferences across all sites, suggesting that this species is highly vulnerable to the impacts of climate‐induced coral loss on reefs. Our results indicate that vulnerability assessments based on some specialisation indices may be misleading and the best estimates of dietary specialisation will be provided by indices which incorporate resource availability measures, as well as assessing responses of species to changes in resource availability.     

Efficacy of different indices derived from spectral reflectance of wheat for nitrogen stress detection

Abstract

The productivity of cereal crops is mainly related to their nitrogen status. It is hypothesized that the spectral reflectance data could be used to predict wheat nitrogen status with spectral indices and that their performance depends on the nature of the interaction of the solar radiation with the crop canopy. A wheat crop was raised with 12 levels of nitrogen treatments: 0, 15, 30, 40, 50, 60, 70, 80, 90, 100, 110, and 120 kg ha^?1, with uniform phosphorous and potassium nutrition and uniform water and management practice. The spectral reflectance measurements of the crop canopy were taken at 5 nm intervals, throughout the crop growth period. Different spectral indices, both broadband (ratio as well as orthogonal) and hyperspectral indices were computed throughout the growing season. Canopy Colour Difference (ΔE), an index developed from the entire visible region and hence broader than the spectral indices developed hitherto, was also estimated from the reflectance data. Simple linear relationships developed between spectral indices versus applied nitrogen levels as well as the plant nitrogen content revealed that the hyperspectral indices are less sensitive in comparison to broadband indices. The result was reinforced by a higher correlation between the colour difference, NDVI and Greenness Index with plant nitrogen level/content, as opposed to hyperspectral indices.     

The organism tolerance to extreme factors: physiological basis, regulation, prediction

The modern ideas about organism reactivity and tolerance, approaches to their estimation and prediction were observed in the paper. The ionizing radiation used as the basic factor, because this factor is the most convenient for the experimental investigation and experimental modeling of the different factors. The individual radiotolerance were observed as the reflection and the component of the organism general nonspecific tolerance. The enough voluminous of different physical factors combined influences were investigated, their reciprocally modified influences to the organism tolerance were estimated. The investigation of mammalian organism tolerance types and tactics of adaptation to the repeated influence of the stress-factors opens the new way to their estimation and prediction. The enough simple and reliable method of the individual tolerance (in particular, with used of the hormonal regulation system indices) were devised. This method is more effective than methods devised earlier.