oxy]ethoxy]ethyl methacrylate (2) and 2- [2-[2-[(tert-butyldimethylsilyl)oxy]ethoxy]ethoxy]ethyl methacrylate (3) were polymerized anionically in THF at -78 °C for 2-24 h. The anionic initiator systems included 1,1-diphenyl-3-methylpentyllithium/lithium chloride and diphenylmethylpotassium/diethylzinc. The polymerization of novel tert-butyldimethylsilyl-protected oligo-(ethylene glycol) methacrylates, 2 and 3, proceeded quantitatively in each case. The resulting polymers possessed the predicted molecular weights based on the molar ratios of monomers to initiators, and narrow molecular weight distributions (M w/Mn < 1.1). The stability of the propagating carbanion of poly(2) and poly(3) was ascertained by the quantitative efficiencies of the sequential block copolymerizations using tert-butyl methacrylate (tBMA). Well-defined block copolymers, poly(2)-block-poly(tBMA) and poly(3)block-poly(tBMA), were obtained. The trialkylsilyl protecting groups of poly(2) and poly(3) were quantitatively hydrolyzed using 2 N HCl in aqueous THF at 0 °C for 2 h to give tailored poly[di(ethylene glycol) methacrylate] and poly[tri(ethylene glycol) methacrylate], respectively. Both polymethacrylates obtained after deprotection were readily soluble in water due to the high polarity of the hydrophilic oligo-(ethylene glycol) pendant units with terminal OH functionality.

We report a unique case of acute cholecystitis due to strangulation of a floating gallbladder by the lesser omentum, which could be detected by abdominal ultrasonography. We believe this case to be the first case of reported literatures in English.

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