RESUMO
Cooling devices based on caloric materials have emerged as promising candidates to become the next generation of coolers. Several electrocaloric (EC) heat exchangers have been proposed that use different mechanisms and working principles. However, a prototype that demonstrates a competitive temperature span has been missing. We developed a parallel-plate active EC regenerator based on lead scandium tantalate multilayer capacitors. After optimizing the structural design by using finite element modeling for guidance and to considerably improve insulation, we measured a maximum temperature span of 13.0 kelvin. This temperature span breaks a crucial barrier and confirms that EC materials are promising candidates for cooling applications.
RESUMO
Polymorphonuclear cells (PMNs) from healthy donors and differentiated HL-60 cells were compared in an opsonophagocytic assay using fluorescent latex beads coated with Streptococcus pneumoniae polysaccharide conjugates. Serum-specific phagocytosis was efficiently mediated by both sources of cells, as measured by flow cytometry, but the mean number of beads ingested per cell was three- to fivefold higher when PMNs were used than when HL-60 cells were used. Nevertheless, differentiated HL-60 cells could be a convenient and standardized source of cells to evaluate the functionality of specific antibodies to vaccine candidates as a coating on fluorescent beads.