19 research outputs found

    Scalability considerations for multivariate graph visualization

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    Real-world, multivariate datasets are frequently too large to show in their entirety on a visual display. Still, there are many techniques we can employ to show useful partial views-sufficient to support incremental exploration of large graph datasets. In this chapter, we first explore the cognitive and architectural limitations which restrict the amount of visual bandwidth available to multivariate graph visualization approaches. These limitations afford several design approaches, which we systematically explore. Finally, we survey systems and studies that exhibit these design strategies to mitigate these perceptual and architectural limitations

    High Strength Discontinuously Reinforced Aluminum For Rocket Applications

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    This study presents results on the development of a new aluminum alloy with very high strength and ductility. Five compositions of Al-Mg-Sc-Gd-Zr alloy were selected for this purpose. These alloys were also reinforced with 15 volume percent silicon-carbide and boron-carbide particles to produce Discontinuously Reinforced Aluminum (DRA) materials. Matrix alloys and DRA were processed using a powder metallurgy process. The helium gas atomization produced very fine powder with cellular-dentritic microstructure. The microstructure of matrix alloys showed fine Al3Sc based precipitate which provides significant strengthening in these alloys. DRA showed uniform distribution of reinforcement in aluminum matrix. DRA materials were tested at -320 F, 75 F in air and 7S F in gaseous hydrogen environments and matrix alloys were tested at 75 F in air. DRA showed high strengths in the range of 89-111 ksi (614-697 MPa) depending on alloy compositions and test environments. Matrix alloys had a good combination of strength, 84-89 ksi (579-621 MPa) and ductility, 4.5-6.5%. The properties of these materials can further be improved by proper control of processing parameters

    Requirement for Class II Phosphoinositide 3-Kinase C2α in Maintenance of Glomerular Structure and Function▿

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    An early lesion in many kidney diseases is damage to podocytes, which are critical components of the glomerular filtration barrier. A number of proteins are essential for podocyte filtration function, but the signaling events contributing to development of nephrotic syndrome are not well defined. Here we show that class II phosphoinositide 3-kinase C2α (PI3KC2α) is expressed in podocytes and plays a critical role in maintaining normal renal homeostasis. PI3KC2α-deficient mice developed chronic renal failure and exhibited a range of kidney lesions, including glomerular crescent formation and renal tubule defects in early disease, which progressed to diffuse mesangial sclerosis, with reduced podocytes, widespread effacement of foot processes, and modest proteinuria. These findings were associated with altered expression of nephrin, synaptopodin, WT-1, and desmin, indicating that PI3KC2α deficiency specifically impacts podocyte morphology and function. Deposition of glomerular IgA was observed in knockout mice; importantly, however, the development of severe glomerulonephropathy preceded IgA production, indicating that nephropathy was not directly IgA mediated. PI3KC2α deficiency did not affect immune responses, and bone marrow transplantation studies also indicated that the glomerulonephropathy was not the direct consequence of an immune-mediated disease. Thus, PI3KC2α is critical for maintenance of normal glomerular structure and function by supporting normal podocyte function

    The physiological effects of deleting the mouse SLC30A8 gene encoding zinc transporter-8 are influenced by gender and genetic background.

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    The SLC30A8 gene encodes the islet-specific transporter ZnT-8, which is hypothesized to provide zinc for insulin-crystal formation. A polymorphic variant in SLC30A8 is associated with altered susceptibility to type 2 diabetes. Several groups have examined the effect of global Slc30a8 gene deletion but the results have been highly variable, perhaps due to the mixed 129SvEv/C57BL/6J genetic background of the mice studied. We therefore sought to remove the conflicting effect of 129SvEv-specific modifier genes.The impact of Slc30a8 deletion was examined in the context of the pure C57BL/6J genetic background.Male C57BL/6J Slc30a8 knockout (KO) mice had normal fasting insulin levels and no change in glucose-stimulated insulin secretion (GSIS) from isolated islets in marked contrast to the ∼50% and ∼35% decrease, respectively, in both parameters observed in male mixed genetic background Slc30a8 KO mice. This observation suggests that 129SvEv-specific modifier genes modulate the impact of Slc30a8 deletion. In contrast, female C57BL/6J Slc30a8 KO mice had reduced (∼20%) fasting insulin levels, though this was not associated with a change in fasting blood glucose (FBG), or GSIS from isolated islets. This observation indicates that gender also modulates the impact of Slc30a8 deletion, though the physiological explanation as to why impaired insulin secretion is not accompanied by elevated FBG is unclear. Neither male nor female C57BL/6J Slc30a8 KO mice showed impaired glucose tolerance.Our data suggest that, despite a marked reduction in islet zinc content, the absence of ZnT-8 does not have a substantial impact on mouse physiology

    Prolonging the circulatory retention of SPIONs using dextran sulfate : in vivo tracking achieved by functionalisation with near-infrared dyes

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    <p>Intraperitoneal (Panels <b>A</b> and <b>C</b>) and oral (Panel <b>B</b>) glucose tolerance tests were performed on 6 hr fasted conscious C57BL/6J WT (closed symbols) and <i>Slc30a8</i> KO (open symbols) male mice as described in Materials and Methods. The IPGTT results in Panel <b>A</b> show the mean glucose concentrations ± S.E.M. in WT (n = 11; mean age ∼20 weeks) and <i>Slc30a8</i> KO (n = 9; mean age ∼20 weeks) animals. The OGTT results in Panel <b>B</b> show the mean glucose concentrations ± S.E.M. in WT (n = 16; mean age ∼22 weeks) and <i>Slc30a8</i> KO (n = 9; mean age ∼22 weeks) animals. The IPGTT results in Panel <b>C</b> show the mean glucose concentrations ± S.E.M. in WT (n = 17; mean age ∼4 weeks) and <i>Slc30a8</i> KO (n = 19; mean age ∼4 weeks) animals. *p<0.05 <i>versus</i> WT.</p

    Biochemical characterization of C57BL/6J <i>Slc30a8</i> KO mice.

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    <p><b>Panel A:</b> Immunohistochemical staining of wild type and <i>Slc30a8</i> KO mouse pancreas with antisera raised to insulin, glucagon, and ZnT-8 was performed as described in Materials and Methods. Representative pictures are shown. WT, wild type; KO, knockout. <b>Panel B:</b> Zinc content in isolated islets was determined as described in Material and Methods. Results represent the mean ± S.E.M. (n = 3 independent islet preparations for each genotype with each islet preparation assayed in quintuplicate). *p<0.05 <i>versus</i> WT.</p
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