Influence of morphology and polymorphic transformation of fat crystals on the freeze-thaw stability of mayonnaise-type oil-in-water emulsions.

This study examined the destabilization of an oil-in-water (O/W) emulsion by freeze-thawing with a focus on the influence of the morphology and polymorph of fat crystals. For a model of food emulsion, this study used a mayonnaise-type O/W emulsion containing 70wt% canola oil (canola emulsion) or soybean oil (soybean emulsion) stored at -15, -20, and -30°C. The freeze-thaw stabilities of the emulsions were evaluated by measuring the upper oil layer after freeze-thawing. The soybean emulsion kept at -20°C had the highest stability; the other emulsions were destabilized during 6h of storage. Crystallization in the emulsions was determined using differential scanning calorimetry (DSC), time variation of temperature, X-ray diffraction measurement, and polarized light microscopy. DSC thermograms indicated that crystallization in emulsions occurred first in the high-melting fraction of oil, followed by water and, last, in the low-melting fraction of oil during cooling to -40°C. In the canola emulsion, the amount of fat crystals derived from the low-melting fraction of oil increased during storage at all temperatures, resulting in partial coalescence. The soybean emulsion was expected to be destabilized by polymorphic transformation (sub-α to ß' and ß) of fat crystals derived from the high-melting fraction during storage at -15 and -20°C. However, the soybean emulsion did not exhibit polymorphic transformation stored at -30°C, and the amount of fat crystals did not increase during freezing; thus, it was destabilized via a different mechanism.

Intracranial Aneurysm Embolization Using Interlocking Detachable Coils. Correlation between Volume Embolization Rate and Coil Compaction.

SUMMARY: The relationship between volume embolization ratio . and coil compaction on the intracranial aneurysm occluded using interlocking detachable coils (IDCs) was determined. From February 1994 to October 1996, 7 intracranial aneurysms were embolized using IDCs. Aneurysm capacity (volume) was calculated assuming that aneurysms are ellipsoid of the diameter in 3 planes. Coil volume was calculated assuming that IDCs are cylinders of primary coil. Coil compaction was observed in aneurysms embolized at a volume embolization ratio under 25%. There was no coil compaction in aneurysms embolized at a volume embolization ratio of over 25%. Measurement of the volume embolization ratio is useful to predict coil compaction. Intracranial aneurysms should be embolized at a volume embolization ratio of 25-33%.