148 research outputs found

    Corrosion Behaviors of Aluminum Following a Loss of Coolant Accident

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    Aluminum (Al) corrosion in the containment of nuclear reactor has detrimental effects on the performance of emergency-core–cooling system (ECCS). In a loss-of-coolant accident (LOCA), the ECCS is initiated to shut down the operation of a nuclear power plant safely. The cooling alkaline solution flowing through the ECCS has a high concentration of boric acid, which has been suggested to be corrosive to Al alloy. Precipitations caused by Al corrosion potentially obstructs the sump screens while the solution is re-circulated in the nuclear core through ECCS. This study aims to understand the release and corrosion behaviors of Al alloy exposed to the boron-containing alkaline solution. The corrosion rate of Al was determined through obtaining the mass of Al released into the solution as well as the formation of scale on the Al sample. The test conditions were referenced for the prior literature reviews as well as the actual design of PWR. To explore further into the effect of Al corrosion towards the ECCS, the effects of temperature, pH and submersion time of Al which exposed to the borate buffer solution have been studied. Experiments were undertaken in a shaker table equipment which simulates the conditions of Al exposure to the containment sump following a LOCA. Results have shown that at a higher temperature, the corrosion rate of Al was significantly higher. Across a period of submersion time of Al in solution, the corrosion rate of Al decreased drastically. Al corrosion rate is higher at higher pH and temperature. At 85C, the dissolved Al re-deposit on the sample surface which makes less Al dissolved in solution.Nuclear Materials and Fuel Cycle Research CenterAlion Science and TechnologyNo embargoAcademic Major: Mechanical Engineerin

    Association of Caucasian-identified variants with colorectal cancer risk in Singapore Chinese

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    Background: Genome-wide association studies (GWAS) in Caucasians have identified fourteen index single nucleotide polymorphisms (iSNPs) that influence colorectal cancer (CRC) risk. Methods: We investigated the role of eleven iSNPs or surrogate SNPs (sSNPs), in high linkage disequilibrium (LD, r2≥0.8) and within 100 kb vicinity of iSNPs, in 2,000 age- and gender-matched Singapore Chinese (SCH) cases and controls. Results: Only iSNP rs6983267 at 8q24.21 and sSNPs rs6695584, rs11986063, rs3087967, rs2059254, and rs7226855 at 1q41, 8q23.3, 11q23.1, 16q22.1 and 18q21.1 respectively showed evidence of association with CRC risk, with odds ratios (OR) ranging from 1.13 to 1.40. sSNP rs827401 at 10p14 was associated with rectal cancer risk (OR = 0.74, 95% CI 0.63-0.88) but not disease prognosis (OR = 0.91, 95% CI 0.69-1.20). Interestingly, sSNP rs3087967 at 11q23.1 was associated with CRC risk in men (OR = 1.34, 95% CI 1.14-1.58) but not women (OR = 1.07, 95% CI: 0.88-1.29), suggesting a gender-specific role. Half of the Caucasian-identified variants, including the recently fine-mapped BMP pathway loci, BMP4, GREM1, BMP2 and LAMA 5, did not show any evidence for association with CRC in SCH (OR ~1; p-value >0.1). Comparing the results of this study with that of the Northern and Hong Kong Chinese, only variants at chromosomes 8q24.21, 10p14, 11q23.1 and 18q21.1 were replicated in at least two out of the three Chinese studies. Conclusions: The contrasting results between Caucasians and Chinese could be due to different LD patterns and allelic frequencies or genetic heterogeneity. The results suggest that additional common variants contributing to CRC predisposition remained to be identified. © 2012 Thean et al

    The nonhuman condition: Radical democracy through new materialist lenses

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    This Critical Exchange explores the nonhuman condition. It asks: What are the implications of decentering the human subject via a new materialist reading of radical democracy? Does this reading dilute political agency? Or should this be seen, on the contrary, as an invitation for new voices and demands to enter into democratic assemblages? How might engagement with the more-than-human disrupt or extend theories of radical democracy? In our introductory contribution, we engage with the radical democratic human subject and explore new materialist thinking and its challenge to anthropocentrism. We offer a preliminary answer to how democratic agency is reconfigured under the nonhuman condition. While these questions have no final answers, we show that engaging with them opens a fruitful conversation about the limits and content of radical democracy

    Xkr8 Modulates Bipolar Cell Number in the Mouse Retina

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    The present study interrogated a quantitative trait locus (QTL) on Chr 4 associated with the population sizes of two types of bipolar cell in the mouse retina. This locus was identified by quantifying the number of rod bipolar cells and Type 2 cone bipolar cells across a panel of recombinant inbred (RI) strains of mice derived from two inbred laboratory strains, C57BL/6J (B6/J) and A/J, and mapping a proportion of that variation in cell number, for each cell type, to this shared locus. There, we identified the candidate gene X Kell blood group precursor related family member 8 homolog (Xkr8). While Xkr8 has no documented role in the retina, we localize robust expression in the mature retina via in situ hybridization, confirm its developmental presence via immunolabeling, and show that it is differentially regulated during the postnatal period between the B6/J and A/J strains using qPCR. Microarray analysis, derived from whole eye mRNA from the entire RI strain set, demonstrates significant negative correlation of Xkr8 expression with the number of each of these two types of bipolar cells, and the variation in Xkr8 expression across the strains maps a cis-eQTL, implicating a regulatory variant discriminating the parental genomes. Xkr8 plasmid electroporation during development yielded a reduction in the number of bipolar cells in the retina, while sequence analysis of Xkr8 in the two parental strain genomes identified a structural variant in the 3′ UTR that may disrupt mRNA stability, and two SNPs in the promoter that create transcription factor binding sites. We propose that Xkr8, via its participation in mediating cell death, plays a role in the specification of bipolar cell number in the retina

    Music-related activities on Facebook

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    Despite the current prevalence of users performing musical activities on social media, and on Facebook in particular, little research has examined these behaviors from the perspective of consumer psychology. A cross-sectional, convenience sample of 400 participants (Mage = 22.56, SDage = 7.79) completed an online questionnaire. The findings illustrated that the constructs of opinion leadership, innovativeness, and self-efficacy within the consumer psychology literature were associated with performing music-related activities on Facebook, including the active creation/consumption of music content and use of music listening applications. Thus, music activities performed on Facebook have an overt consumer psychological component. These findings indicate that to understand music-related activities on social media, further research should consider psychological variables in explaining this common and economically important activity

    Impacts of Habitat Degradation on Tropical Montane Biodiversity and Ecosystem Services: A Systematic Map for Identifying Future Research Priorities

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    Tropical montane forests (TMFs) are major centers of evolutionary change and harbor many endemic species with small geographic ranges. In this systematic map, we focus on the impacts of anthropogenic habitat degradation on TMFs globally. We first determine how TMF research is distributed across geographic regions, degradation type (i.e., deforestation, land-use conversion, habitat fragmentation, ecological level (i.e., ecosystem, community, population, genetic) and taxonomic group. Secondly, we summarize the impacts of habitat degradation on biodiversity and ecosystem services, and identify deficiencies in current knowledge. We show that habitat degradation in TMFs impacts biodiversity at all ecological levels and will be compounded by climate change. However, despite montane species being perceived as more extinction-prone due to their restricted geographic ranges, there are some indications of biotic resilience if the impacts to TMFs are less severe. Species richness and key species interactions can be maintained in mildly degraded sites, and gene flow can persist between TMF fragments. As such, minimally degraded areas such as secondary forests and restored areas could play a crucial role in maintaining the meta-community and ecosystem services of TMFs—either via resource provision or by linking patches of pristine forest. Research deficiencies highlighted include poor research representation in Asian and African TMFs, few assessments of population and genetic-level responses to fragmentation, and little assessment of the impacts of habitat fragmentation at all ecological levels. To address these concerns, we present a list of the top research priorities to urgently address the growing threat of habitat degradation in TMF
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