Neutron Embrittlement of WWER Reactors: EC-Supported Projects

Results of the implementation of programs on the evaluation of service life of reactor pressure vessels of NPP are considered with the account of neutron embrittlement. Data on strength of WWER-440 reactor pressure vessels with a high and moderate content of detrimental impurities (copper and phosphor) have been analyzed. For the welds of WWER-1000 reactor, drawbacks in the manufacture, dosimetry, and test procedures of surveillance specimens are shown. To ensure safe operations of reactor pressure vessels, new projects have been undertaken, focusing on the effect of neutron embrittlement of steel on the integrity of structures and advanced experimental methods of studying material strength.Представлены результаты исследований по определению ресурса корпусных сталей АЭС с учетом радиационного охрупчивания. Проанализированы данные по изучению прочности корпусов реакторов ВВЭР-440 с высоким и умеренным содержанием вредных примесей (медь и фосфор) в стали. Для сварных соединений отмечены недостатки процедуры испытаний образцов-свидетелей, технологии их изготовления, нейтронной дозиметрии. С целью обеспечения надежной эксплуатации корпусов реакторов разработаны новые проекты, направленные на изучение влияния радиационного охрупчивания сталей на структурную целостность и усовершенствование экспериментальных методов оценки прочности материалов.Представлено результати досліджень щодо визначення ресурсу корпусних сталей AEC з урахуванням радіаційного окрихчення. Проаналізовано дані про міцність корпусів реакторів BBEP-440 із високим і помірним вмістом шкідливих домішок (мідь і фарфор) у сталі. Для зварних з ’єднань відмічено недоліки процедури випробувань зразків-свідків, технології їх виготовлення, нейтронної дозиметрії. Із метою забезпечення надійної експлуатації корпусів реакторів розроблено нові проекти, що направлені на вивчення впливу радіаційного окрихчування сталей на структурну цілісність та удосконалення експериментальних методів оцінки міцності матеріалів

Interactions between the Aggregatibacter actinomycetemcomitans secretin HofQ and host cytokines indicate a link between natural competence and interleukin-8 uptake

Naturally competent bacteria acquire DNA from their surroundings to survive in nutrient-poor environments and incorporate DNA into their genomes as new genes for improved survival. The secretin HofQ from the oral pathogen Aggregatibacter actinomycetemcomitans has been associated with DNA uptake. Cytokine sequestering is a potential virulence mechanism in various bacteria and may modulate both host defense and bacterial physiology. The objective of this study was to elucidate a possible connection between natural competence and cytokine uptake in A. actinomycetemcomitans. The extramembranous domain of HofQ (emHofQ) was shown to interact with various cytokines, of which IL-8 exhibited the strongest interaction. The dissociation constant between emHofQ and IL-8 was 43 nM in static settings and 2.4 μM in dynamic settings. The moderate binding affinity is consistent with the hypothesis that emHofQ recognizes cytokines before transporting them into the cells. The interaction site was identified via crosslinking and mutational analysis. By structural comparison, relateda type I KH domain with a similar interaction site was detected in the Neisseria meningitidis secretin PilQ, which has been shown to participate in IL-8 uptake. Deletion of hofQ from the A. actinomycetemcomitans genome decreased the overall biofilm formation of this organism, abolished the response to cytokines, i.e., decreased eDNA levels in the presence of cytokines, and increased the susceptibility of the biofilm to tested β-lactams. Moreover, we showed that recombinant IL-8 interacted with DNA. These results can be used in further studies on the specific role of cytokine uptake in bacterial virulence without interfering with natural-competence-related DNA uptake

The changing nature of labour regulation: the distinctiveness of the National Agreement for the Engineering Construction Industry

The article addresses the changing nature of labour regulation through analysis of the National Agreement for the Engineering Construction Industry, originating in 1981. It shows how multiple spatial regulatory scales, the changing coalitions of actors involved, employer and client engagement and labour agency have been critical to National Agreement for the Engineering Construction Industry's survival

Travel Tales of a Worldwide Weed: Genomic Signatures of Plantago major L. Reveal Distinct Genotypic Groups With Links to Colonial Trade Routes

Retracing pathways of historical species introductions is fundamental to understanding the factors involved in the successful colonization and spread, centuries after a species’ establishment in an introduced range. Numerous plants have been introduced to regions outside their native ranges both intentionally and accidentally by European voyagers and early colonists making transoceanic journeys; however, records are scarce to document this. We use genotyping-by-sequencing and genotype-likelihood methods on the selfing, global weed, Plantago major, collected from 50 populations worldwide to investigate how patterns of genomic diversity are distributed among populations of this global weed. Although genomic differentiation among populations is found to be low, we identify six unique genotype groups showing very little sign of admixture and low degree of outcrossing among them. We show that genotype groups are latitudinally restricted, and that more than one successful genotype colonized and spread into the introduced ranges. With the exception of New Zealand, only one genotype group is present in the Southern Hemisphere. Three of the most prevalent genotypes present in the native Eurasian range gave rise to introduced populations in the Americas, Africa, Australia, and New Zealand, which could lend support to the hypothesis that P. major was unknowlingly dispersed by early European colonists. Dispersal of multiple successful genotypes is a likely reason for success. Genomic signatures and phylogeographic methods can provide new perspectives on the drivers behind the historic introductions and the successful colonization of introduced species, contributing to our understanding of the role of genomic variation for successful establishment of introduced taxa.publishedVersio

Travel Tales of a Worldwide Weed: Genomic Signatures of Plantago major L. Reveal Distinct Genotypic Groups With Links to Colonial Trade Routes

Retracing pathways of historical species introductions is fundamental to understanding the factors involved in the successful colonization and spread, centuries after a species’ establishment in an introduced range. Numerous plants have been introduced to regions outside their native ranges both intentionally and accidentally by European voyagers and early colonists making transoceanic journeys; however, records are scarce to document this. We use genotyping-by-sequencing and genotype-likelihood methods on the selfing, global weed, Plantago major, collected from 50 populations worldwide to investigate how patterns of genomic diversity are distributed among populations of this global weed. Although genomic differentiation among populations is found to be low, we identify six unique genotype groups showing very little sign of admixture and low degree of outcrossing among them. We show that genotype groups are latitudinally restricted, and that more than one successful genotype colonized and spread into the introduced ranges. With the exception of New Zealand, only one genotype group is present in the Southern Hemisphere. Three of the most prevalent genotypes present in the native Eurasian range gave rise to introduced populations in the Americas, Africa, Australia, and New Zealand, which could lend support to the hypothesis that P. major was unknowlingly dispersed by early European colonists. Dispersal of multiple successful genotypes is a likely reason for success. Genomic signatures and phylogeographic methods can provide new perspectives on the drivers behind the historic introductions and the successful colonization of introduced species, contributing to our understanding of the role of genomic variation for successful establishment of introduced taxa.info:eu-repo/semantics/publishedVersio

New TACIS Regional Projects on Radiation Embrittlement and Integrity Assessment of WWER Reactor Pressure Vessels.

Abstract not availableJRC.F-Institute for Energy (Petten