Affinity purified anticardiolipin antibodies (ACLA) raised in rabbits showed cross-reactivities with various negatively charged phospholipids as shown by both the solid phase enzyme-linked immunosorbent assay (ELISA) and inhibition studies. In ELISA, ACLA showed strong cross-reactivity to both sphingomyelin (SM) and phosphatidylethanolamine (PE), but the inhibition studies showed that ACLA failed to bind the aqueous suspensions of SM, PE, and PE/PC (1:1). ACLA bound to resting gel-filtered human platelets (GFP) as shown by both inhibition study and flow cytofluorometric analysis. Western blotting procedure showed that ACLA strongly cross-reacted to an 80-Kd plasma membrane protein. ACLA activated platelet response in a concentration-dependent manner. At less than 10 micrograms/mL, ACLA induced both platelet shape change to spiculate irregular forms as shown by scanning electron microscopy and the phosphorylation of 20-Kd protein. ACLA at more than 10 micrograms/mL caused platelet aggregation and secretion. The aggregation was inhibited by EDTA; aspirin; antimycin A plus 2-deoxyglucose; PGE1; and the F(ab')2 fragment of ACLA. It was not inhibited by monoclonal antibody to Fc receptor (MoAb FcR2). The biochemical events of ACLA-induced platelet response involved the elevation of (1) thromboxane A2 formation, (2) cytosolic free calcium ion concentration ([Ca2+]i), and (3) 47-Kd protein phosphorylation. In addition, the subaggregatory concentration of ACLA showed synergistic platelet activation with that concentration of thrombin, collagen, and epinephrine. The study showed the mechanism involved in ACLA-induced platelet responses.
Flat mill products of Zircaloy-4 and controlled-chemistry Zircaloy-2 were processed using different rolling schedules in order to generate different textures and other metallurgical conditions. Tubular products of three heats of controlled-chemistry Zircaloy-2 were also processed using various thermo-mechanical parameters and different tube reduction schedules. Samples were taken for 500 and 520°C steam autoclave tests and texture and microstructure examination. Intermetallic precipitates were analyzed for mean diameters and particle size distributions using optical high magnification photographs. Matrix concentrations of Fe, Cr, and Ni were analyzed by electron microprobe with automated stage control. Results showed that the nodular corrosion resistance for controlled-chemistry Zircaloy-2 was excellent, while that for Zircaloy-4 was rather poor. The Zircaloy-2 tubeshell may be annealed up to 663°C/2h without detriment to the nodular corrosion resistance of the final size tubing if other fabrication variables are properly controlled. The optimum process for tube reducing is a high Q ratio and high percent of reduction in area. Neither β quench nor α + β treatment after tube extrusion is required to produce cladding tube that is free of nodules in 500 or 520°C autoclave tests. Low basal pole densities are generally related to high corrosion weight gains. The accumulated annealing parameter, ΣA, can generally predict the nodular corrosion behavior of the material, but it cannot account for the higher corrosion weight gain at an intermediate stage and lower weight gain at the final size. The most significant correlation is established between variation in concentrations of iron, chrome, and nickel in Zircaloy-2 and nodular corrosion behavior of the material. A depletion of these elements in the matrix or a large spacing between intermetallic precipitates causes poor nodular corrosion resistance. The positive effect of cold work on the nodular corrosion resistance is attributed to increasing the yield strength of the substrate.
Antigonon leptopus has been naturalized in Taiwan for about 100 years, but hitherto no fungal species was recorded on this plant in Taiwan. A powdery mildew fungus collected on A. leptopus in central and northern Taiwan was identified as Erysiphe polygoni based on internal transcribed spacer sequence comparison and morphology of the anamorph.
Zircaloy-2 controlled chemistry tubes were fabricated using different tubeshell annealing temperatures and tube reduction schedules. The results of this set of materials was previously presented in ASTM STP 1132. This paper presents new results from texture and transmission electron microscopy (TEM) microstructure investigations on the same set of materials. Samples with various processing histories were examined by TEM microscopy to characterize the intermetallic precipitate distributions and matrix solute concentration. Matrix concentration profiles across a 2-μm length were obtained in scanning transmission electron microscopy (STEM) mode using an electron beam spot of approximately 0.07 μm on high and low corrosion resistant material. The influence of texture on corrosion was also examined by fabricating specimens with radial textures (fr) values from approximately 0.3 to 0.6. The results show that the tube reduction schedule has a very significant influence on nodular corrosion behavior. The accumulated reduction factor was established to define the influence of deformation during tube reducing on texture. High fr on the final cladding suppressed the nodular corrosion behavior regardless of the precipitate size. This leads to conflicting evidence on the role of precipitate size and corrosion behavior. Micro-zones of solute segregation in the matrix were also detected above the solubility limits of α-zirconium on some final cladding specimens.
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