484 research outputs found

    SRB water impact velocity trade study

    Get PDF
    The results of the attrition/cost studies which formulated the data base for the recommendation to reduce the Space Shuttle Solid Rocket Booster's nominal vertical water impact velocity to 85 feet per second is presented

    Reduced tubulin tyrosination as an early marker of mercury toxicity in differentiating N2a cells

    Get PDF
    The aims of this work were to compare the effects of methyl mercury chloride and Thimerosal on neurite/process outgrowth and microtubule proteins in differentiating mouse N2a neuroblastoma and rat C6 glioma cells. Exposure for 4 h to sublethal concentrations of both compounds inhibited neurite outgrowth to a similar extent in both cells lines compared to controls. In the case of N2a cells, this inhibitory effect by both compounds was associated with a fall in the reactivity of western blots of cell extracts with monoclonal antibody T1A2, which recognises C-terminally tyrosinated Ī±-tubulin. By contrast, reactivity with monoclonal antibody B512 (which recognises total Ī±-tubulin) was unaffected at the same time point. These findings suggest that decreased tubulin tyrosination represents a neuron-specific early marker of mercury toxicity associated with impaired neurite outgrowth

    Aurora-A Phosphorylates, Activates, and Relocalizes the Small GTPase RalA

    Get PDF
    The small GTPase Ras, which transmits extracellular signals to the cell, and the kinase Aurora-A, which promotes proper mitosis, can both be inappropriately activated in human tumors. Here, we show that Aurora-A in conjunction with oncogenic Ras enhances transformed cell growth. Furthermore, such transformation and in some cases also tumorigenesis depend upon S194 of RalA, a known Aurora-A phosphorylation site. Aurora-A promotes not only RalA activation but also translocation from the plasma membrane and activation of the effector protein RalBP1. Taken together, these data suggest that Aurora-A may converge upon oncogenic Ras signaling through RalA

    Autoreactive T cell profiles are altered following allogeneic islet transplantation with alemtuzumab induction and reā€emerging phenotype is associated with graft function

    Get PDF
    Islet transplantation is an effective therapy for lifeā€threatening hypoglycemia, but graft function gradually declines over time in many recipients. We characterized isletā€specific T cells in recipients within an islet transplant program favoring alemtuzumab (ATZ) lymphodepleting induction and examined associations with graft function. Fiftyā€eight recipients were studied: 23 pretransplant and 40 posttransplant (including 5 with pretransplant phenotyping). The proportion with isletā€specific T cell responses was not significantly different over time (preā€Tx: 59%; 1ā€“6 m posttransplant: 38%; 7ā€“12 m: 44%; 13ā€“24 m: 47%; and >24 m: 45%). However, phenotype shifted significantly, with IFNā€Ī³ā€“dominated response in the pretransplant group replaced by ILā€10ā€“dominated response in the 1ā€“6 m posttransplant group, reverting to predominantly IFNā€Ī³ā€“oriented response in the >24 m group. Clustering analysis of posttransplant responses revealed two main agglomerations, characterized by IFNā€Ī³ and ILā€10 phenotypes, respectively. ILā€10ā€“oriented posttransplant response was associated with relatively low graft function. Recipients within the ILā€10+ cluster had a significant decline in Cā€peptide levels in the period preceding the ILā€10 response, but stable graft function following the response. In contrast, an IFNā€Ī³ response was associated with subsequently decreased Cā€peptide. Islet transplantation favoring ATZ induction is associated with an initial altered isletā€specific T cell phenotype but reversion toward pretransplant profiles over time. Posttransplant autoreactive T cell phenotype may be a predictor of subsequent graft function

    The pleasures and perils of inheritance

    Get PDF
    Facing death, reflecting on oneā€™s legacies (material and ethical, personal and political) and the legal and interpersonal attempts to resolve or prevent inheritance conflicts, all bring to the fore constructions of memory and identity, intergenerational relations, and the complexities of doing and undoing family and kinship. Consequently, drawing attention to inheritance, keeping sight of it, and bringing it into play is a useful piece of the puzzle of ageing across a range of disciplines and this article provides an overview of some of the key themes in this emerging field

    Extra-Activism: Counter-Mapping and Data Justice

    Get PDF
    Neither big data, nor data justice are particularly new. Data collection, in the form of land surveys and mapping, was key to successive projects of European imperialist and then capitalist extraction of natural resources. Geo-spatial instruments have been used since the fifteenth century to highlight potential sites of mineral, oil, and gas extraction, and inscribe European economic, cultural and political control across indigenous territories. Although indigenous groups consistently challenged maintained their territorial sovereignty, and resisted corporate and state surveillance practices, they were largely unable to withstand the combined onslaught of surveyors, armed personnel, missionaries and government bureaucrats. This article examines the use of counter-mapping by indigenous nations in Canada, one of the globeā€™s hubs of extractivism, as part of the exercise of indigenous territorial sovereignty. After a brief review of the colonial period, I then compare the use of counter-mapping during two cycles of indigenous mobilization. During the 1970s, counter-mapping projects were part of a larger repertoire of negotiations with the state over land claims, and served to re-inscribe first nationā€™s long-standing history of economic, social and cultural relations in their territories, and contribute to new collective imaginaries and identities. In the current cycle of contests over extractivism and indigenous sovereignty, the use, scope and geographic scale of counter-mapping has shifted; maps are used as part of larger trans-media campaigns of Indigenous sovereignty. During both cycles, counter-mapping as data justice required fusion within larger projects of redistributive, transformative and restorative justice

    Elevated Human Telomerase Reverse Transcriptase Gene Expression in Blood Cells Associated with Chronic Arsenic Exposure in Inner Mongolia, China

    Get PDF
    Background Arsenic exposure is associated with human cancer. Telomerase-containing human telomerase reverse transcriptase (hTERT) can extend telomeres of chromosomes, delay senescence, and promote cell proliferation leading to tumorigenesis.ObjectiveThe goal of this study was to investigate the effects of As on hTERT mRNA expression in humans and in vitro. Method A total of 324 Inner Mongolia residents who have been exposed to As via drinking water participated in this study. Water and toenail samples were collected and analyzed for As. Blood samples were quantified for hTERT mRNA expression using real-time polymerase chain reaction. The hTERT mRNA levels were linked to water and nail As concentrations and skin hyperkeratosis. Human epidermal keratinocytes were treated with arsenite to assess effects on cell viability and hTERT expression in vitro.ResultshTERT mRNA expression levels were significantly associated with As concentrations of water (p < 0.0001) and nails (p = 0.002) and also associated with severity of skin hyperkeratosis (p < 0.05), adjusting for age, sex, smoking, and pesticide use. Females showed a higher slope than males (females: 0.126, p = 0.0005; males: 0.079, p = 0.017). In addition to water and nail As concentrations, age (p < 0.0001) and pesticide use (p = 0.025) also showed significant associations with hTERT expression. The hTERT expression levels decreased with age. Tobacco smoking did not affect hTERT expression (p = 0.13). hTERT expression was significantly correlated with OGG1 and ERCC1 expression. The in vitro results also showed a doseā€“response relationship between arsenite concentrations and hTERT expression and reached the peak at 1 Ī¼M. Conclusion shTERT expression was associated with As exposure in vivo and in vitro. The increased hTERT expression may be a cellular response to genomic insults by As and may also indicate that As may function as a tumor promoter in carcinogenesis in humans

    RALA and RALBP1 regulate mitochondrial fission atĀ mitosis

    Get PDF
    Mitochondria exist as dynamic interconnected networks that are maintained through a balance of fusion and fission1. Equal distribution of mitochondria to daughter cells during mitosis requires fission2. Mitotic mitochondrial fission depends upon both the relocalization of large GTPase Drp1 to the outer mitochondrial membrane and phosphorylation of S616 on Drp1 by the mitotic kinase cyclin B/Cdk12. We now report that these processes are mediated by the small Ras-like GTPase RalA and its effector RalBP1 (RLIP76/RLIP1/RIP1)3,4. Specifically, the mitotic kinase Aurora A phosphorylates S194 of RalA, relocalizing it to the mitochondria, where it concentrates RalBP1 and Drp1. Furthermore, RalBP1 associates with cyclin B/Cdk1 kinase activity to foster phosphorylation of Drp1 on S616. Disrupting either RalA or RalBP1 leads to a loss of mitochondrial fission at mitosis, improper segregation of mitochondria during cytokinesis and a decrease in ATP levels and cell number. Thus, the two mitotic kinases Aurora A and cyclin B/Cdk1 converge upon RalA and RalBP1 to promote mitochondrial fission, the appropriate distribution of mitochondria to daughter cells and ultimately proper mitochondrial function
    • ā€¦
    corecore