27 research outputs found

    Gamma radiation induces hydrogen absorption by copper in water

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    One of the most intricate issues of nuclear power is the long-term safety of repositories for radioactive waste. These repositories can have an impact on future generations for a period of time orders of magnitude longer than any known civilization. Several countries have considered copper as an outer corrosion barrier for canisters containing spent nuclear fuel. Among the many processes that must be considered in the safety assessments, radiation induced processes constitute a key-component. Here we show that copper metal immersed in water uptakes considerable amounts of hydrogen when exposed to γ-radiation. Additionally we show that the amount of hydrogen absorbed by copper depends on the total dose of radiation. At a dose of 69 kGy the uptake of hydrogen by metallic copper is 7 orders of magnitude higher than when the absorption is driven by H2(g) at a pressure of 1 atm in a non-irradiated dry system. Moreover, irradiation of copper in water causes corrosion of the metal and the formation of a variety of surface cavities, nanoparticle deposits, and islands of needle-shaped crystals. Hence, radiation enhanced uptake of hydrogen by spent nuclear fuel encapsulating materials should be taken into account in the safety assessments of nuclear waste repositories.Peer reviewe

    Shaping Skeletal Growth by Modular Regulatory Elements in the Bmp5 Gene

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    Cartilage and bone are formed into a remarkable range of shapes and sizes that underlie many anatomical adaptations to different lifestyles in vertebrates. Although the morphological blueprints for individual cartilage and bony structures must somehow be encoded in the genome, we currently know little about the detailed genomic mechanisms that direct precise growth patterns for particular bones. We have carried out large-scale enhancer surveys to identify the regulatory architecture controlling developmental expression of the mouse Bmp5 gene, which encodes a secreted signaling molecule required for normal morphology of specific skeletal features. Although Bmp5 is expressed in many skeletal precursors, different enhancers control expression in individual bones. Remarkably, we show here that different enhancers also exist for highly restricted spatial subdomains along the surface of individual skeletal structures, including ribs and nasal cartilages. Transgenic, null, and regulatory mutations confirm that these anatomy-specific sequences are sufficient to trigger local changes in skeletal morphology and are required for establishing normal growth rates on separate bone surfaces. Our findings suggest that individual bones are composite structures whose detailed growth patterns are built from many smaller lineage and gene expression domains. Individual enhancers in BMP genes provide a genomic mechanism for controlling precise growth domains in particular cartilages and bones, making it possible to separately regulate skeletal anatomy at highly specific locations in the body

    Life Cycle Impact Assessment

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    International audienceThis chapter is dedicated to the third phase of an LCA study, the Life Cycle Impact Assessment (LCIA) where the life cycle inventory's information on elementary flows is translated into environmental impact scores. In contrast to the three other LCA phases, LCIA is in practice largely automated by LCA software, but the underlying principles, models and factors should still be well understood by practitioners to ensure the insight that is needed for a qualified interpretation of the results.This chapter teaches the fundamentals of LCIA and opens the black box of LCIA with its characterisation models and factors to inform the reader about: (1) the main purpose and characteristics of LCIA, (2) the mandatory and optional steps of LCIA according to the ISO standard, and (3) the science and methods underlying the assessment for each environmental impact category. For each impact category, the reader is taken through (a) the underlying environmental problem, (b) the underlying environmental mechanism and its fundamental modelling principles, (c) the main anthropogenic sources causing the problem and (d) the main methods available in LCIA. An annex to this book offers a comprehensive qualitative comparison of the main elements and properties of the most widely used and also the latest LCIAmethods for each impact category, to further assist the advanced practitioner to make an informed choice between LCIA methods

    Expression of the follistatin/EGF-containing transmembrane protein M7365 (tomoregulin-1) during mouse development

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    A novel transmembrane protein (designated X7365) containing two follistatin modules and an epidermal growth factor (EGF) domain has been described in the hypothalamic-pituitary axis of Xenopus laevis. We have now cloned the highly conserved mouse orthologue (M7365), and its mRNA was detected in many mesodermal and (neuro)ectodermal tissues in 8.5-day-old mouse embryos. During further development, M7365 mRNA expression became restricted to certain regions in the brain and to ganglia. In the adult mouse, the brain is the major site of M7365 expression.status: publishe

    Methodology for systematic analysis and improvement of manufacturing unit process life-cycle inventory (UPLCI)—CO2PE! initiative (cooperative effort on process emissions in manufacturing). Part 1: Methodology description

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    LINK: http://www.springerlink.com/content/ygn87mq1x217752w/Purpose: This report proposes a life cycle analysis (LCA)-oriented methodology for systematic inventory analysis of manufacturing unit processes (referred to as unit process life cycle inventories, UPLCI). The methodology has been developed in the framework of the CO2PE! collaborative research programme and comprises two approaches with different levels of detail, respectively referred to as the screening approach and the in-depth approach. Methodology: The screening approach relies on representative publicly available data and theoretical calculations for energy use, material loss, and identification of variables for improvement, while the in-depth approach is subdivided into four modules, including a time study, a power consumption study, a consumables study and an emissions study, in which all relevant process in- and outputs are measured and analysed in detail. The screening approach provides the first insight in the unit process and results in a set of approximate LCI-data, which also serve to guide the more detailed and complete in-depth approach leading to more accurate LCI-data as well as the identification of potential for energy and resource efficiency improvements of the manufacturing unit process. To ensure optimal reproducibility and applicability, documentation guidelines for data and metadata are included in both approaches. Guidance on definition of functional unit and reference flow as well as on determination of system boundaries specifies the generic goal and scope definition requirements according to ISO 14040 (2006) and ISO 14044 (2006). Results: The proposed methodology aims at ensuring solid foundations for the provision of high-quality LCI data for manufacturing unit processes. Envisaged usage encompasses the provision of high-quality data for LCA studies of products using these UPLCI for the manufacturing processes, as well as the in-depth analysis of individual manufacturing unit processes. In addition, the accruing availability of data for a range of similar machines (same process, different suppliers and machine capacities) will allow the establishment of parametric emission and resource use estimation models for a more streamlined LCA of products including reliable manufacturing process data. Both approaches have already provided useful results in some initial case studies and their use will be illustrated by two case studies in Part 2 of this paper in the next issue of this journal.status: publishe
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