485 research outputs found
SRB water impact velocity trade study
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
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
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 reāemerging phenotype is associated with graft function
Islet transplantation is an effective therapy for lifeāthreatening hypoglycemia, but graft function gradually declines over time in many recipients. We characterized isletāspecific T cells in recipients within an islet transplant program favoring alemtuzumab (ATZ) lymphodepleting induction and examined associations with graft function. Fiftyāeight recipients were studied: 23 pretransplant and 40 posttransplant (including 5 with pretransplant phenotyping). The proportion with isletāspecific T cell responses was not significantly different over time (preāTx: 59%; 1ā6 m posttransplant: 38%; 7ā12 m: 44%; 13ā24 m: 47%; and >24 m: 45%). However, phenotype shifted significantly, with IFNāĪ³ādominated response in the pretransplant group replaced by ILā10ādominated response in the 1ā6 m posttransplant group, reverting to predominantly IFNāĪ³āoriented response in the >24 m group. Clustering analysis of posttransplant responses revealed two main agglomerations, characterized by IFNāĪ³ and ILā10 phenotypes, respectively. ILā10āoriented posttransplant response was associated with relatively low graft function. Recipients within the ILā10+ cluster had a significant decline in Cāpeptide levels in the period preceding the ILā10 response, but stable graft function following the response. In contrast, an IFNāĪ³ response was associated with subsequently decreased Cāpeptide. Islet transplantation favoring ATZ induction is associated with an initial altered isletāspecific 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
Facing death, reflecting on oneās 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
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 globeās 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 nationās 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
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 doseāresponse 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
The impact of time to death in donors after circulatory death on recipient outcome in simultaneous pancreas-kidney transplantation
\ua9 2024 The AuthorsThe time to arrest donors after circulatory death is unpredictable and can vary. This leads to variable periods of warm ischemic damage prior to pancreas transplantation. There is little evidence supporting procurement team stand-down times based on donor time to death (TTD). We examined what impact TTD had on pancreas graft outcomes following donors after circulatory death (DCD) simultaneous pancreas-kidney transplantation. Data were extracted from the UK transplant registry from 2014 to 2022. Predictors of graft loss were evaluated using a Cox proportional hazards model. Adjusted restricted cubic spline models were generated to further delineate the relationship between TTD and outcome. Three-hundred-and-seventy-five DCD simultaneous kidney-pancreas transplant recipients were included. Increasing TTD was not associated with graft survival (adjusted hazard ratio HR 0.98, 95% confidence interval 0.68-1.41, P = .901). Increasing asystolic time worsened graft survival (adjusted hazard ratio 2.51, 95% confidence interval 1.16-5.43, P = .020). Restricted cubic spline modeling revealed a nonlinear relationship between asystolic time and graft survival and no relationship between TTD and graft survival. We found no evidence that TTD impacts pancreas graft survival after DCD simultaneous pancreas-kidney transplantation; however, increasing asystolic time was a significant predictor of graft loss. Procurement teams should attempt to minimize asystolic time to optimize pancreas graft survival rather than focus on the duration of TTD
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