716 research outputs found

    Automatic recognition of vector and parallel operations in a higher level language

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    A compiler for recognizing statements of a FORTRAN program which are suited for fast execution on a parallel or pipeline machine such as Illiac-4, Star or ASC is described. The technique employs interval analysis to provide flow information to the vector/parallel recognizer. Where profitable the compiler changes scalar variables to subscripted variables. The output of the compiler is an extension to FORTRAN which shows parallel and vector operations explicitly

    Oscillation dynamics of embolic microspheres in flows with red blood cell suspensions

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    Dynamic nature of particle motion in blood flow is an important determinant of embolization based cancer therapy. Yet, the manner in which the presence of high volume fraction of red blood cells influences the particle dynamics remains unknown. Here, by investigating the motions of embolic microspheres in pressure-driven flows of red blood cell suspensions through capillaries, we illustrate unique oscillatory trends in particle trajectories, which are not observable in Newtonian fluid flows. Our investigation reveals that such oscillatory behavior essentially manifests when three simultaneous conditions, namely, the Reynolds number beyond a threshold limit, degree of confinement beyond a critical limit, and high hematocrit level, are fulfilled simultaneously. Given that these conditions are extremely relevant to fluid dynamics of blood or polymer flow, the observations reported here bear significant implications on embolization based cancer treatment as well as for complex multiphase fluidics involving particle

    Promoting Population Health in Local Communities: Parental Perceptions of an Embedded Movement and Physical Activity Program for a Preschool Population

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    Background: Many children reach kindergarten lacking age-appropriate motor skills because of a lack of access to early intervention services or a lack of continued early intervention beyond 3 years of age. Research suggests sedentary children become sedentary adults, which contributes to a growing population of unhealthy Americans with chronic health conditions, such as high blood pressure, diabetes, heart disease, and psychosocial difficulties. Parents often are not aware of the benefits of engaging in physical activity or possess a lack of awareness of their local resources. A community based preschool movement program was created to foster physical activity and promote carryover through participation in family activities. Method: A program evaluation design model was used to explore parental perceptions of their child’s interest and participation in physical activities. Knowledge of local resources was also measured. Results: The parent responses reported an increase in interest for physical activities by their child along with an increase in parental understanding of the value of movement in daily routines. The family’s awareness of local resources increased as a result of the movement program and supporting materials. Conclusion: Collaborating with existing entities can further parental education about movement and non-sedentary routines. Future research is needed to measure outcomes over time

    HLA-Ig Based Artificial Antigen Presenting Cells for Efficient ex vivo Expansion of Human CTL

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    CTL with optimal effector function play critical roles in mediating protection against various intracellular infections and cancer. However, individuals may exhibit suppressive immune microenvironment and, in contrast to activating CTL, their autologous antigen presenting cells may tend to tolerize or anergize antigen specific CTL. As a result, although still in the experimental phase, CTL-based adoptive immunotherapy has evolved to become a promising treatment for various diseases such as cancer and virus infections. In initial experiments ex vivo expanded CMV (cytomegalovirus) specific CTL have been used for treatment of CMV infection in immunocompromised allogeneic bone marrow transplant patients. While it is common to have life-threatening CMV viremia in these patients, none of the patients receiving expanded CTL develop CMV related illness, implying the anti-CMV immunity is established by the adoptively transferred CTL1. Promising results have also been observed for melanoma and may be extended to other types of cancer2

    Increased TCR Avidity after T Cell Activation A Mechanism for Sensing Low-Density Antigen

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    AbstractWhile activated T cells are known to have enhanced biological responses to antigen stimulation, the biophysical basis of this increased sensitivity remains unknown. Here, we show that, on activated T cells, the TCR avidity for peptide-MHC complexes is 20- to 50-fold higher than the TCR avidity of naive T cells. This increased avidity for peptide-MHC depends on TCR reorganization and is sensitive to the cholesterol content of the T cell membrane. Analysis of the binding data indicates the enhanced avidity is due to increases in cross-linking of TCR on activated T cells. Activation-induced membrane (AIM) changes in TCR avidity represent a previously unrecognized means of increasing the sensitivity of activated T cells to small amounts of antigen in the periphery

    Reducing the positional modulation of NbO6-octahedra in SrxBa1-xNb2O6 by increasing the Barium content: A single crystal neutron diffraction study at ambient temperature for x=0.61 and x=0.34

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    We report on the influence of the Barium content on the modulation amplitude in SrxBa1-xNb2O6 compounds by comparing Sr0.61Ba0.39Nb2O6 (SBN61) and Sr0.34Ba0.66Nb2O6 (SBN34). Our single crystal neutron diffraction results demonstrate that the amplitude of the positional modulation of the NbO6 octahedra is reduced with increasing barium content, indicating that the origin of the modulation is the partial occupation of the pentagonal channels by Sr and Ba atoms. By increasing the Sr content the bigger Ba atoms are replaced by the smaller Sr atoms, which leads to a larger deformation of the surrounding lattice and hence to a larger modulation amplitude. The more homogeneous the filling of these channels with one atomic type (Ba) the lower the modulation amplitude. Our results also show that the structure can be described with a two-dimensional incommensurate harmonic modulation. No second order modulation has been observed, both by single crystal diffraction measurements and q-scans. The positional modulation of the Nb atoms is much smaller than that of the oxygen atoms, such that the modulation can be seen as a rotational modulation of almost rigid NbO6-octahedra
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