Lipid droplet accumulation in the foam cells
was evaluated by a microscope (Leica, German).
Bertoni et al (2) proposed the term primary xanthoma of bone for those cases in which no apparent underlying condition can be identified and the predominant finding is a collection of foam cells
Inflammatory changes without foam cell
lesions and typical atheromata have also been observed in C.
i60] foams with all kenaf core loading percentages due to dense packing of more number of smaller foam cells
as seen from ESEM images.
The main trends seem to be modifications of different sets of genes, which lead to (1) increased recruitment of monocytes and smooth muscle cells; (2) increased survival of lipid-laden cells; (3) increased LDL uptake by ECs and macrophages; (4) decreased protein synthesis; (5) decreased antimicrobial potential, proliferation, and motility of macrophages/ foam cells
2] levels, the rapid crystalline nucleation and growth than occur simultaneously with the foam cell
growth played a role that essentially overwhelmed the effect of chain-extension.
Ordinarily, HDLs -- the so called "good" lipoproteins -- can withdraw cholesterol from foam cells
and target it for removal from the body.
The rate of quenching controls the time available to the foam cells
to keep growing and then stabilize subsequently.
Various researchers have proposed strategies for foam cell
opening: blending of polymers, plasticization of the soft region with a secondary blow agent, increasing the expansion ratio, and particulate leaching (10), (11).
Proprietary processing is said to reduce pigment agglomerates to individual particles that are smaller and distribute more uniformly in urethane foam cells
Regardless of the processing technique, the foaming of polymers by using physical blowing agents, such as carbon dioxide or nitrogen, relies on the same principles: (1) the polymer is saturated with the blowing agent at high pressures, (2) the polymer-gas mixture is quenched into a supersaturated state by reducing the pressure and/or increasing the temperature, (3) the thermodynamic instability of supersaturation leads to nucleation of foam cells
, (4) the growth of the foam cells
, driven by the diffusion of the blowing agent, proceeds until the cells either stabilize or rupture.
The size of the foam cells
is determined by the amount and rate of SCF flow into the barrel, as well as the temperature and pressure of the melt.