Terahertz Radiation at ANKA, the New Synchrotron Light Source in Karlsruhe

ANKA is a new synchrotron light source atthe Karlsruhe Research Center in southwestGermany. The acronym stands for Ångstrøm Source Karlsruhe.The ANKA-IR beamline provides a highbrilliance infrared beam through the near,mid and far-infrared range. Thefar-infrared range is of particularinterest, since at frequencies lower thanaround 200 cm^-1 (6 THz) synchrotronlight begins to outperform conventionalthermal sources in terms of total intensityas well as brilliance. The extraction ofthe entire flux is a challenge in the THzrange, since the natural verticaldivergence of synchrotron radiationincreases with wavelength and the openingangle for collection is limited by designconstraints. At ANKA-IR, this problem issolved by the collection of radiationemitted from a bending magnet edge source,which has a much smaller verticaldivergence than conventional synchrotronradiation emitted from the constantmagnetic field region within the dipolemagnet. Edge radiation at ANKA permits theextraction of the entire infrared flux downto around 100 cm^-1 (3 THz) while withconventional synchrotron radiation thiswould only be the case for frequencies downto 2500 cm^-1. ANKA-IR provides usableintensity down to 4 cm^-1 (120 GHz).     

A new paradigm in leaf-level photosynthesis: direct and diffuse lights are not equal

Global-change scenarios suggest a trend of increasing diffuse light due to expected increases in cloud cover. Canopy-level measurements of plant-community photosynthesis under diffuse light show increased productivity attributed to more uniform distribution of light within the forest canopy, yet the effect of the directional quality of light at the leaf level is unknown. Here we show that leaf-level photosynthesis in sun leaves of both C(3) and C(4) plants can be 10-15% higher under direct light compared to equivalent absorbed irradiances of diffuse light. High-light-grown leaves showed significant photosynthetic enhancement in direct light, while shade-adapted leaves showed no preference for direct or diffuse light at any irradiance. High-light-grown leaves with multiple palisade layers may be adapted to better utilize direct than diffuse light, while shade leaf structure does not appear to discriminate light based on its directionality. Based upon our measurements, it appears that leaf-level and canopy-level photosynthetic processes react differently to the directionality of light, and previously observed increases in canopy-level photosynthesis occur even though leaf-level photosynthesis decreases under diffuse light.     

Thermal assessment of zoological exhibits I: Sea lion enclosure at the Audubon Zoo

The objectives of this study were twofold: first, to develop noninvasive techniques for measuring the thermal characteristics of materials commonly used in construction of zoological exhibits; and second, to use these techniques to compare a portion of the Audubon Zoo's sea lion exhibit before and after renovations completed in 1993. We characterized the thermal environment of the sea lion enclosures by diurnal measurements of the two primary heat gain components, longwave and shortwave radiation. Measurements of wet sea lion coats showed that they absorbed 91.6% of all types of shortwave radiation. The surface of gunite “rocks” in the enclosure in 1991 reflected 41% of shortwave radiation, while the same area, after renovation, reflected only 8% of shortwave radiation. Darkening the color of the gunite surfaces and adding two effective shaded areas to the enclosure decreased the shortwave heat load in the exposed beach areas and the longwave heat load in the shaded areas. We conclude that thermal properties of materials used in zoo enclosures are an important determinant of the animals' heat load and should be considered in the design of captive habitats. © 1996 Wiley-Liss, Inc.     

电离辐射诱导基因的研究进展

电离辐射诱导基因是一类受电离辐射调控表达的基因,其表达随辐射条件和所处生理环境的不同呈现复杂多变的特征。电离辐射诱导基因参与细胞内各种代谢途径,在细胞周期调控、细胞生长调节、细胞凋亡、DNA损伤修复中发挥着重要的作用。介绍了电离辐射诱导基因的种类、功能,及其引起的生物效应的分子机制及应用。     

Adaptive radiotherapy in patients receiving neoadjuvant radiation for soft tissue sarcoma

AimThe aim of this study is to evaluate tumor volume changes during preoperative radiotherapy and to assess the role of adaptive radiation.BackgroundContemporary neoadjuvant radiotherapy utilizes image guidance for precise treatment delivery. Moreover, it may depict changes in tumor size and shape.Materials and methodsBetween 2016 and 2018, 23 patients aged ≥18 years with soft tissue sarcoma were treated with neoadjuvant radiation followed by surgical resection. The tumor volumes (cc) were measured using the Pinnacle planning system prior to starting radiotherapy and during treatment, the changes in volume and absolute differences were estimated. Moreover, patient's position on the machine was evaluated to assess setup offsets. The triggers for plan adaptation were >1 cm expansion or unacceptable setup offsets.ResultsThe mean tumors volume at presentation was 810 cc (range, 55–4000). At last cone beam CT the tumor volume had changed in 14 patients (61%); it was stable in nine patients (39%). Disease regression was documented in eight patients (35%), with median shrinkage of −20.5% (range, −2 to −29%), while tumor progression was observed in six cases (26%), the median change was 12.5% (range, +10 to +25%).Adaptive radiation was required in four patients (17%). For the remaining 19 cases (83%), the dose distribution was adequate to cover target volumes.ConclusionsChange in soft tissue sarcoma volume during radiation is not uncommon. Image guidance should be used to reduce setup errors and to detect differences in tumor volume. Image guidance and adaptive radiation are paramount to ensure optimal radiation delivery.     

Resistance to schistosome infection in Biomphalaria glabrata induced by gamma radiation

Two strains of Biomphalaria glabrata were studied with respect to the effects of ionizing radiation on their susceptibility to Schistosoma mansoni infection. Gamma radiation at levels of 3.5 and 5 krad did not induce susceptibility in the resistant S-3 strain, but was found to initiate resistance in the susceptible PR-1 strain. In an attempt to understand the induced resistance in irradiated snails, histopathologic examinations and analyses of snail hemolymph were performed. Results indicated that miracidia invading irradiated snails were quickly surrounded and encapsulated by amoebocytes. Similarly, alterations in the hemolymph of irradiated snails suggested that radiation induced aging. It is suggested that radiation-altered snails may be of value in studying the defense mechanisms of these organisms.     

Quantifying shade using a standard environment

The purpose of this study was to quantify the thermal microclimate provided by a shade structure in the African elephant enclosure at Zoo Atlanta. The hypothesis was that the interior of a weather instrument shelter (a Stevenson screen) would provide the maximum environmental shielding and the coolest possible ambient conditions without artificial heating or cooling. The ambient conditions inside the Stevenson screen were compared with the ambient conditions in the shaded and nonshaded sections of the exhibit to quantify the extremes possible under the environmental conditions. The Stevenson screen reduced the radiant heat load by 766 W m^?2. The shade structure in the elephant enclosure reduced the radiant heat load by 278 W m^?2, which was 37% of the total possible reduction represented by the interior of the Stevenson screen. The longwave radiant heat was 10% greater in the direct sun and 37% greater in the shaded area than the shortwave radiant heat. The shade structure reduced the shortwave radiant heat by 254 W m^?2 or 43%, but only reduced the longwave radiant heat by 24Wm^?2 or 3%. Shade structures alone may not provide adequate protection from radiant heat for captive species. A cool microclimate in an artificial enclosure should be designed to reduce all sources of radiant heat. Zoo Biol 22:253–260, 2003. © 2003 Wiley‐Liss, Inc.     

Effect of superoxide dismutase on early radiation injury of lungs in the rat

Early responses of lungs to a single radiation dose of 30 Gy were marked by an inflammatory reaction and the onset of pneumonitis within 4 weeks following hemithorax radiation in the rat. Superoxide dismutase reduced the severity of radiation lesions in lungs.     

The Synchrotron Infrared Activities at BESSY

The new multipurpose infrared (IR) beamlineat the electron storage ring BESSY IIprovides highly brilliant infrared radiation forstructural and time resolved studies in thebiological and material science. With this facility newresearch possibilities at BESSY are madeavailable to the scientific community.     

Effects of pubescence and waxes on the reflectance of leaves in the ultraviolet and photosynthetic wavebands: a comparison of a range of species

Total reflectance of ultraviolet and photosynthetically effective wavelengths was measured for a range of different leaf types. Two approaches were employed. Firstly, reflectance of monochromatic wavebands at 330 and 680 nm was measured for a total of 45 different species covering a wide range of genera. In the second, specific leaf types that displayed different degrees of reflectance were treated to remove hairs and waxes that contributed to their reflectance. Selected waxy and non‐waxy leaves were also studied in more detail over the spectral range 270–500 nm. It was found that both pubescence (presence of hairs) and glaucousness (presence of a thick epicuticular wax layer) had marked effects on total reflectance. Pubescent leaves tended to be more effective in reflecting longer wavelengths than ultraviolet radiation. The extent of this effect depended on hair type. Glaucous leaves demonstrated that surface waxes were very effective reflectors of both UV and longer wavelength radiation.     

Expanding radiation quarantine treatments beyond fruit flies

1 The potential of ionizing radiation as a disinfestation treatment for insects other than tephritid fruit flies is discussed. Radiation quarantine treatments are unique in that insects are not killed immediately but rendered sterile or incapable of completing development. 2 The most tolerant insect stage to radiation is that which is most developed. Female insects, but not always mites, are sterilized with equal or lower doses than males. 3 Insects irradiated with sterilizing doses usually have shorter longevities than non‐irradiated ones. Low oxygen conditions often increase tolerance to radiation. 4 Insects in diapause are not more tolerant of radiation than non‐diapausing ones. 5 Some pests of several groups, such as aphids, whiteflies, weevils, scarab beetles, and fruit flies, may be controlled with doses ≤ 100 Gy. Some lepidopterous pests and most mites require about 300 Gy. Stored product moths may require as much as 1 kGy to sterilize, and nematodes could need > 4 kGy. 6 Even though application of irradiation to pallet‐loads of produce could mean that up to three times the minimum required dose is applied to the perimeter of the pallet, many fresh commodities tolerate doses required for quarantine security against many quarantined pests. Irradiation is arguably the most widely applicable quarantine treatment from the standpoint of commodity quality.     

Effect of solar ultraviolet radiation on growth in the marine macroalga Dictyota dichotoma (Phaeophyceae) at Helgoland and its ecological consequences

At Helgoland, in the North Sea, growth of the high sublittoral brown macroalga Dictyota dichotoma (Hudson) Lamoroux was examined in October (the time of tetraspore release) in an outdoor tank by exposing 2-day-old germlings to four solar radiation treatments achieved with different filter materials or an additional artificial light source: photosynthetically active radiation (PAR; 395–700 nm), PAR plus ultraviolet (UV)-A (320–700 nm), full solar spectrum, or solar spectrum plus artificial UV radiation (UVR). Based on length measurements over a period of 3 weeks, the growth rate in germlings strongly decreased in conditions with UVR compared to PAR: by 14% under PAR+UV-A, by 31% under the full solar spectrum and by 65% with additional UVR. Although growth rates of germlings under UVR were reduced mainly in the first week, the plants did not regain the size of the untreated plants even after 9 weeks. Regardless of the exposure, no defects in morphology or anatomy including the exposed apical meristem were detected, except for a reduction in cell division rates perhaps due to additional cost for photoprotective or repair mechanisms. Depending on the actual position of D. dichotoma plants in the natural habitat, individuals in high positions receive substantial amounts of the more harmful UV-B while those lower down might only receive UV-A during part of the day, thus the effect of UV-B on the growth of D. dichotoma will depend on its position in the field. The effects of tidal variation of the light climate and the implications of our results for the zonation of D. dichotoma are discussed. Received in revised form: 6 July 2000 Electronic Publication     

Influence of 2.45-GHz CW microwave radiation on spontaneously beating rat atria

The chronotropic and inotropic effects of 2.45-GHz continuous wave (CW) microwave radiation were investigated in the isolated spontaneously beating rat atria. Isolated atria were placed in specially designed tubes inserted into a waveguide exposure system. The atria were then irradiated for a period of 30 min, followed by a 30-min recovery period. The control atria were prepared simultaneously and sham exposed. Experiments were conducted at two temperatures, 22 and 37 °C, and two specific absorption rates, 2 mW/g and 10 mW/g. At both temperatures the rate of atrial contraction was not altered by a 30-min exposure at either 2 or 10 mW/g. The average rate (beats per min) was approximately 100 for both the control and exposed atria at 22 °C and 215 beats per min for both the control and exposed atria at 37 °C. In addition, no inotropic effects on the spontaneously beating atria were noted at any exposure level. These data suggest that 2.45-GHz CW microwave radiation at these intensities has no overt effect on these variables in isolated rat atria.     

A preliminary classification of evolutionary radiations

Rapid increases in taxonomic diversity are generally described as adaptive or evolutionary radiations. Such radiations differ widely in the rate and extent of morphologic innovation, taxonomic diversification and phylogenetic breadth, suggesting that several patterns, and likely processes, are involved. At least four distinct patterns of evolutionary radiation can be identified: novelty events, which generate new morphological complexity (altering the body plan of the group under consideration) but not necessarily with the associated production of many lower taxa; broad diversification events involving many independent lineages that undergo diversification, generate many new species and are driven by new ecological opportunities; economic radiations of a limited group of ecologically (but not necessarily phylogenetically) related clades exploiting a limited new ecologic opportunity; and adaptive radiations that may occur at any taxonomic level, but involve a rapid increase in diversity within a single clade, including “true”; adaptive radiations. Many events produce simple diversity increases with no corresponding increase in genetic/developmental/morphological/behavioral sophistication, but the most evolutionarily interesting events add new levels of complexity.     

长波紫外线辐射对脊椎动物的影响

臭氧层空洞的加剧使紫外辐射不断加强,造成的环境污染已经成为广为关注的问题,但大多数都集中在中波紫外线(UVB)的生物学作用及其与两栖动物衰减关系的研究,有关长波紫外线(UVA)对生物体损伤作用的研究却甚少。本文综述了近年来UVA对脊椎动物损伤的研究概况,从细胞结构、酶活性、遗传物质、膜结构以及免疫系统等方面阐述了UVA的损伤机理,并对低剂量辐射诱导兴奋效应对紫外损伤的保护作用进行了简要概述。最后分析和总结了关于UVA损伤研究所存在的问题及两栖动物作为实验用动物模型在研究紫外线损伤中的作用。     

Stomatal Responses of Bean (Phaseolus Vulgaris L.) Leaves to Changing Irradiance,Air Humidity,and Water Potential of Root Medium

Stomatal responses of attached bean (Phaseolus vulgaris L.) leaves to changing spectral composition ("white" - WL., blue - BL, or red - RL radiation), air humidity (100 % or about 4 % RH), and water potential of the root medium (close to 0 or −1.2 MPa) were determined by air flow porometer. Opening of stomata always increased under BL and decreased under RL. In response to decline in air humidity, leaf conductance showed transient increase before it reached lowered steady state. BL enhanced and RL diminished this response. This revised version was published online in June 2006 with corrections to the Cover Date.     

Measurement of leaf epidermal transmittance of UV radiation by chlorophyll fluorescence

In higher plants one of the important functions of the leaf epidermis is the effective screening of ultraviolet-B (280–320 nm, UV-B) radiation, due mostly to phenolic compounds. The assessment of the contribution of this function is necessary for an evaluation of the impact of increasing UV-B radiation. A method is proposed to estimate epidermal transmittance on the basis of chlorophyll fluorescence measurements. Fluorescence of chlorophyll induced by UV-A (320–400 nm, measuring beam centered at 366 nm, half band width 32 nm) or UV-B (measuring beam centered at 314 nm, half band width 18 nm) is compared to that induced by a blue-green measuring light (475 nm, half band width 140 nm). It is shown that the ratios of UV-and blue-green (BG)-induced fluorescence, F(UV-A)/F(BG) and F(UV-B)/F(BG), are relatively constant among leaf samples of various species ( Vicia faba, Spinacia oleracea, Rumex scutatus ) from which the epidermis was removed. In epidermis-free leaves no significant differences were found between adaxial and abaxial leaf sides, suggesting that leaf structure has negligible influence on the F(UV)/F(BG) ratios. On the other hand, fluorescence excitation ratios varied over a vast range when intact leaves from different species and habitats were investigated. Ratios were low in sun leaves and relatively high in shade- and greenhouse-grown leaves. By relating these results to those obtained with epidermis-free leaves, epidermal transmittances for UV-B radiation could be estimated, with values ranging between 1 and 45%. The data demonstrate a large adaptability of epidermal UV-A and UV-B transmittance in higher plants. The proposed method may prove a versatile and relatively simple tool for investigating epidermal UV transmittance complementing established methods.     

Differential effect of ionizing radiation exposure on multipotent and differentiation‐restricted bone marrow mesenchymal stem cells

Debilitating effects of bone marrow from ionizing radiation exposure has been well established for hematopoietic stem cells; however, radiation toxicity of mesenchymal stem cells (MSCs) has been controversial. The present study addressed if ionizing radiation exposure differently affected bone marrow MSCs with various differentiation commitments. Mouse bone‐marrow‐derived MSCs, D1 cells of early passages (≤5 passages; p5) maintained the complete characteristics of multipotent MSCs, whereas, after ≥45 passages (p45) the differentiation capability of D1 cells became partially restricted. Both p5 and p45 D1 cells were subjected to single dose irradiation by radioactive isotope ¹³⁷Cs. Radiation treatment impaired cell renewal and differentiation activities of p5 D1 cells; however, p45 D1 cells were less affected. Radiation treatment upregulated both pro‐ and anti‐apoptotic genes of p5 D1 cells in a dose‐dependent manner, potentially resulting in the various apoptosis thresholds. It was found that constitutive as well as radiation‐induced phosphorylation levels of histone H2AX was significantly higher in p45 D1 cells than in p5 D1 cells. The increased repair activity of DNA double‐strand breakage may play a role for p45 D1 cells to exhibit the relative radioresistance. In conclusion, the radiation toxicity predominantly affecting multipotent MSCs may occur at unexpectedly low doses, which may, in part, contribute to the catabolic pathology of bone tissue. J. Cell. Biochem. 111: 322–332, 2010. © 2010 Wiley‐Liss, Inc.     

No evidence for radiation-induced clastogenic factors after in vitro or in vivo exposure of human blood

Experiments were performed with human plasma irradiated in vitro or in vivo in order to evaluate the extent to which clastogenic factors might disturb the adaptive response to DNA-damaging factors currently studied in our laboratory. The studies were carried out with plasma isolated from whole blood given 4 Gy of X-rays in vitro and with plasma from people receiving local radiotherapy at a total dose of about 60 Gy gamma rays. Addition of irradiated plasma to culture medium did not result in a statistically significant increase in structural aberrations in chromosomes of non-irradiated normal blood.