1,166 research outputs found
Species and temperature measurement in H2/O2 rocket flow fields by means of Raman scattering diagnostics
Validation of Computational Fluid Dynamics (CFD) codes developed for prediction and evaluation of rocket performance is hampered by a lack of experimental data. Non-intrusive laser based diagnostics are needed to provide spatially and temporally resolved gas dynamic and fluid dynamic measurements. This paper reports the first non-intrusive temperature and species measurements in the plume of a 110 N gaseous hydrogen/oxygen thruster at and below ambient pressures, obtained with spontaneous Raman spectroscopy. Measurements at 10 mm downstream of the exit plane are compared with predictions from a numerical solution of the axisymmetric Navier-Stokes and species transport equations with chemical kinetics, which fully model the combustor-nozzle-plume flowfield. The experimentally determined oxygen number density at the centerline at 10 mm downstream of the exit plane is four times that predicted by the model. The experimental number density data fall between those numerically predicted for the exit and 10 mm downstream planes in both magnitude and radial gradient. The predicted temperature levels are within 10 to 15 percent of measured values. Some of the discrepancies between experimental data and predictions result from not modeling the three dimensional core flow injection mixing process, facility back pressure effects, and possible diffuser-thruster interactions
Participation in Special Olympics and Change in Athlete Self-Concept Over 42 Months
The present study investigated changes in the self-concept of 49 athletes with intellectual disabilities participating in traditional Special Olympics over a 42-month period. Athletes were interviewed to assess their perceived general self-worth, physical competence and social acceptance, and involvement in Special Olympics, which was operationalized through an overall standard score combining a number of components. After controlling for baseline levels of self-worth and involvement in Special Olympics, changes in involvement in Special Olympics predicted improved general self-worth. After adjustment for baseline levels of perceived physical competence and involvement in Special Olympics, changes in involvement in Special Olympics predicted perceived physical competence at 42 months.Special Olympics Canada, Canadian Institutes of Health Researc
Bullying Experiences among Children and Youth with Autism Spectrum Disorders
DOI: 10.1007/s10803-011-1241-xFew studies have investigated bullying experiences among children diagnosed with autism spectrum disorders (ASD); however, preliminary research suggests that children with ASD are at greater risk for being bullied than typically developing peers. The aim of the current study was to build an understanding of bullying experiences among children with ASD based on parent reports by examining rates of various forms of bullying, exploring the association between victimization and mental health problems, and investigating individual and contextual variables as correlates of victimization. Victimization was related to child age, internalizing and externalizing mental health problems, communication difficulties, and number of friends at school, as well as parent mental health problems. Bullying prevention and intervention strategies are discussed.Ontario Mental Health Foundatio
Social Characteristics of Students with Autism Spectrum Disorders Across Classroom Settings
Social Characteristics of Students with autism spectrum disorders across Classroom Settings The current study examined the differences in social characteristics between students with autism spectrum disorders (ASD) primarily educated in full inclusion and non full inclusion classrooms. One hundred and forty six parents of children with ASD completed a questionnaire regarding the social experiences of their child. Results indicate that after controlling for severity of disability and age, higher social competence was related to placement in full inclusion classrooms. Regression analyses indicate that ASD severity predicted social competence and quality of friendships, and age and problem behaviour predicted the number of friends outside school. Implications for future studies are discussed
Computation of propulsion-related flowfields using unstructured adaptive meshes
In this paper, we describe a computational fluid dynamics (CFD) technique based on unstructured triangular/tetrahedral meshes. A finite-volume scheme is used in conjunction with a multi-stage Runge-Kutta algorithm. Convergence enhancements in the form of dual time-stepping and time-derivative preconditioning are used to overcome the limitations of conventional multi-stage schemes. The method is applied to propulsion-related flows and shown to perform satisfactorily
Diversity and environmental adaptation of phagocytic cell metabolism
Phagocytes are cells of the immune system that play important roles in phagocytosis, respiratory burst and degranulation-key components of innate immunity and response to infection. This diverse group of cells includes monocytes, macrophages, dendritic cells, neutrophils, eosinophils, and basophils-heterogeneous cell populations possessing cell and tissue-specific functions of which cellular metabolism comprises a critical underpinning. Core functions of phagocytic cells are diverse and sensitive to alterations in environmental- and tissue-specific nutrients and growth factors. As phagocytic cells adapt to these extracellular cues, cellular processes are altered and may contribute to pathogenesis. The considerable degree of functional heterogeneity among monocyte, neutrophil, and other phagocytic cell populations necessitates diverse metabolism. As we review our current understanding of metabolism in phagocytic cells, gaps are focused on to highlight the need for additional studies that hopefully enable improved cell-based strategies for counteracting cancer and other diseases
Parent Empowerment and Mental Health: Understanding Parent Perceptions of the Educational Experience
Parents of children with autism spectrum disorders (ASD) are important partners with schools in ensuring effective education, and it is important to examine the factors that influence parent perceptions of their children’s educational experience. The purpose of this study was to investigate the relations among parent empowerment, parent mental health, and perceptions of children’s educational experience in 176 parents of children with ASD. Parent empowerment and mental health were found to be significant predictors of parents’ perceptions of their child’s educational experience. The importance of understanding constructs such as empowerment and mental health and how they relate to school satisfaction is discussed
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Targeting the vasopressin type-2 receptor for renal cell carcinoma therapy.
Arginine vasopressin (AVP) and its type-2 receptor (V2R) play an essential role in the regulation of salt and water homeostasis by the kidneys. V2R activation also stimulates proliferation of renal cell carcinoma (RCC) cell lines in vitro. The current studies investigated V2R expression and activity in human RCC tumors, and its role in RCC tumor growth. Examination of the cancer genome atlas (TCGA) database, and analysis of human RCC tumor tissue microarrays, cDNA arrays and tumor biopsy samples demonstrated V2R expression and activity in clear cell RCC (ccRCC). In vitro, V2R antagonists OPC31260 and Tolvaptan, or V2R gene silencing reduced wound closure and cell viability of 786-O and Caki-1 human ccRCC cell lines. Similarly in mouse xenograft models, Tolvaptan and OPC31260 decreased RCC tumor growth by reducing cell proliferation and angiogenesis, while increasing apoptosis. In contrast, the V2R agonist dDAVP significantly increased tumor growth. High intracellular cAMP levels and ERK1/2 activation were observed in human ccRCC tumors. In mouse tumors and Caki-1 cells, V2R agonists reduced cAMP and ERK1/2 activation, while dDAVP treatment had the reverse effect. V2R gene silencing in Caki-1 cells also reduced cAMP and ERK1/2 activation. These results provide novel evidence for a pathogenic role of V2R signaling in ccRCC, and suggest that inhibitors of the AVP-V2R pathway, including the FDA-approved drug Tolvaptan, could be utilized as novel ccRCC therapeutics
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