排序方式: 共有23条查询结果,搜索用时 15 毫秒
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Maks CJ Wan XS Ware JH Romero-Weaver AL Sanzari JK Wilson JM Rightnar S Wroe AJ Koss P Gridley DS Slater JM Kennedy AR 《Radiation research》2011,176(2):170-176
In the coming decades human space exploration is expected to move beyond low-Earth orbit. This transition involves increasing mission time and therefore an increased risk of radiation exposure from solar particle event (SPE) radiation. Acute radiation effects after exposure to SPE radiation are of prime importance due to potential mission-threatening consequences. The major objective of this study was to characterize the dose-response relationship for proton and γ radiation delivered at doses up to 2 Gy at high (0.5 Gy/min) and low (0.5 Gy/h) dose rates using white blood cell (WBC) counts as a biological end point. The results demonstrate a dose-dependent decrease in WBC counts in mice exposed to high- and low-dose-rate proton and γ radiation, suggesting that astronauts exposed to SPE-like radiation may experience a significant decrease in circulating leukocytes. 相似文献
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Ni H Balint K Zhou Y Gridley DS Maks C Kennedy AR Weissman D 《Radiation research》2011,175(4):485-492
Space flight conditions within the protection of Earth's gravitational field have been shown to alter immune responses, which could lead to potentially detrimental pathology. An additional risk of extended space travel outside the Earth's gravitational field is the effect of solar particle event (SPE) radiation exposure on the immune system. Organisms that could lead to infection include endogenous, latent viruses, colonizing pathogenics, and commensals, as well as exogenous microbes present in the spacecraft or other astronauts. In this report, the effect of SPE-like radiation on containment of commensal bacteria and the innate immune response induced by its breakdown was investigated at the radiation energies, doses and dose rates expected during an extravehicular excursion outside the Earth's gravitational field. A transient increase in serum lipopolysaccharide was observed 1 day after irradiation and was accompanied by an increase in acute-phase reactants and circulating proinflammatory cytokines, indicating immune activation. Baseline levels were reestablished by 5 days postirradiation. These findings suggest that astronauts exposed to SPE radiation could have impaired containment of colonizing bacteria and associated immune activation. 相似文献
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Nestbox provision is a technique used to increase nest-site availability for secondary cavity-nesting birds. However, little is known about the demographic consequences of nestbox provision in different habitat types. To assess how nestbox provision affects the density of hole-nesting birds simultaneously in two contrasting habitats, we compared the breeding density of Great Tits along transects without nestboxes with that in transects where nestboxes were provided. Although the initial density of breeders was considerably higher in the deciduous habitat than in the coniferous habitat, provision of nestboxes increased density by a similar number of additional pairs in each habitat type. Thus, the provision of nestboxes in managed coniferous forests may be as effective in increasing the breeding opportunities of cavity nesters as in deciduous stands. Moreover, previous research showed that pairs in deciduous habitat with nestboxes have consistently lower breeding success than those in coniferous habitat with nestboxes. It is possible that the addition of nestboxes in the preferred habitat increased density to such an extent that density-dependent effects became apparent. 相似文献
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Andrea Cecchin Mathieu Lamour Michael Joseph Maks Davis David Jcome Polit 《Journal of Industrial Ecology》2019,23(5):1292-1310
Over the last decades, a number of new environmental policies have been designed to improve waste management. Among them, extended producer responsibility (EPR) has introduced a mechanism to shift the environmental and financial burden of end‐of‐life products from public management to producers. Recently, EPR has been adopted by a growing number of developing countries, but this policy often struggles in being effectively implemented in such contexts, missing the opportunity of using waste management as a sustainability driver. By discussing the EPR for end‐of‐life tires (ELTs) in Ecuador, this paper proposes a different approach in designing and implementing EPR schemes in developing countries: it recommends consideration of social sustainability, rather than merely copying foreign management frameworks. To address this point, two case studies on socially directed ELT applications were designed and carried out. The case studies aimed at improving resilience of vulnerable populations to natural disasters by increasing the resistance of housing and settlements against catastrophic events using civil engineering applications. The analysis of the case studies’ outcomes brings to light possible policy adjustments, in which social sustainability goals are taken into account within the national EPR scheme. The Ecuadorian case also highlights the benefit of employing an adaptive governance approach when dealing with challenging urban management topics, such as informality (a widespread phenomenon in developing countries) and resilience. 相似文献
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Wilson JM Sanzari JK Diffenderfer ES Yee SS Seykora JT Maks C Ware JH Litt HI Reetz JA McDonough J Weissman D Kennedy AR Cengel KA 《Radiation research》2011,176(5):649-659
In a solar particle event (SPE), an unshielded astronaut would receive proton radiation with an energy profile that produces a highly inhomogeneous dose distribution (skin receiving a greater dose than internal organs). The novel concept of using megavoltage electron-beam radiation to more accurately reproduce both the total dose and the dose distribution of SPE protons and make meaningful RBE comparisons between protons and conventional radiation has been described previously. Here, Yucatan minipigs were used to determine the effects of a superficial, SPE-like proton dose distribution using megavoltage electrons. In these experiments, dose-dependent increases in skin pigmentation, ulceration, keratinocyte necrosis and pigment incontinence were observed. Five of 18 animals (one each exposed to 7.5 Gy and 12.5 Gy radiation and three exposed to 25 Gy radiation) developed symptomatic, radiation-associated pneumonopathy approximately 90 days postirradiation. The three animals from the highest dose group showed evidence of mycoplasmal pneumonia along with radiation pneumonitis. Moreover, delayed-type hypersensitivity was found to be altered, suggesting that superficial irradiation of the skin with ionizing radiation might cause immune dysfunction or dysregulation. In conclusion, using total doses, patterns of dose distribution, and dose rates that are compatible with potential astronaut exposure to SPE radiation, animals experienced significant toxicities that were qualitatively different from toxicities previously reported in pigs for homogeneously delivered radiation at similar doses. 相似文献
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TE Willnow C Antignac AW Br?ndli EI Christensen RD Cox D Davidson JA Davies O Devuyst G Eichele ND Hastie PJ Verroust A Schedl IC Meij 《Organogenesis》2005,2(2):42-47
Rapid progress in genome research creates a wealth of information on the functional annotation of mammalian genome sequences. However, as we accumulate large amounts of scientific information we are facing problems of how to integrate and relate the data produced by various genomic approaches. Here, we propose the novel concept of an organ atlas where diverse data from expression maps to histological findings to mutant phenotypes can be queried, compared and visualized in the context of a three-dimensional reconstruction of the organ. We will seek proof of concept for the organ atlas by elucidating genetic pathways involved in development and pathophysiology of the kidney. Such a kidney atlas may provide a paradigm for a new systems-biology approach in functional genome research aimed at understanding the genetic bases of organ development, physiology and disease.Key Words: EuReGene, kidney, genome, development, pathophysiology, genetics 相似文献