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New soap‐type surfactants bearing a 1,3‐dioxolane ring were prepared in good yields by the acid‐catalyzed condensation of 1‐O‐alkylglycerols (alkyl: decyl, dodecyl, tetradecyl, heptadecyl, octadecyl, orcis‐9‐octadecenyl) with oxocarboxylic acid esters, followed by alkaline hydrolysis without any expensive reagent and special equipment. These surfactants were soluble in alkaline water at room temperature. Their critical micelle concentrations were much smaller than that of sodium dodecanoate. An alkaline solution of the octadecyl homologue was nonfoaming, but the other homologues, including thecis‐9‐octadecenyl derivative, showed high foaming ability in alkaline solutions. The structural effect of these compounds on the area per molecule at the surface is also discussed. Because these surfactants contain a 1,3‐dioxolane ring, they can be utilized as a new acid‐decomposable type of cleavable surfactant. At pH 1, they decompose almost completely into nonsurface‐active species after 80 min.

This short-term (3-week) intervention study indicates that Lactobacillus helveticus fermented milk may have a more favorable effect on improving sleep in healthy elderly people as compared with placebo.

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