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631.
Sixty-five interactions where an adult male carried an infant in the proximity of a second male were observed during a 19-mo period in a captive sooty mangabey (Cercocebus atys) social group. The behavior was distributed nonrandomly in both the adult male and infant classes. In all but three of the interactions, the recently deposed alpha male carried an infant in the presence of the newly ascendant dominant male. In the first phase of the study, infants that were carried included the entire unweaned infant cohort (n = 5) born before the rank reversal. The rate of carrying in this class declined as a function of increasing infant age and time since the rank reversal. Infant carrying was not observed in the context of fighting, which was rare, and intermale aggression never preceded the behavior. However, in 40% of the cases, carrying occurred after an infant had been threatened by the dominant male. These results suggest that infant carrying served to protect the infant from aggression rather than to exploit the infant as an agonistic buffer. The data did not unequivocally support the postulate that carrying may be a form of paternal care since paternity could not be assessed. The similar structural and contextual patterns of infant carrying in this species suggest a common origin for triadic male-infant interactions in mangabeys and baboons. 相似文献
632.
633.
Mojca Pavlin Vilko Leben Damijan Miklavčič 《Biochimica et Biophysica Acta (BBA)/General Subjects》2007
Electroporation is a process where increased permeability of cells exposed to an electric field is observed. It is used in many biomedical applications including electrogene transfection and electrochemotherapy. Although the increased permeability of the membrane is believed to be the result of pores due to an induced transmembrane voltage Um, the exact molecular mechanisms are not fully explained. 相似文献
634.
A retention model for the chiral separation of an uncharged solute, felodipine, on CHIRAL-AGP, using a micellar mobile phase is proposed. The model assumes the presence of two stereoselective sites and each enantiomer was found to interact with different sites. Addition of a chiral aliphatic alcohol, (+)-(S)-2-octanol, preferentially interacted with the binding site for (?)-(S)-felodipine. The monomeric form of the micellar agent (Tween® 20) competed with the enantiomers for the adsorption sites, and the formation of a 1:1 complex between the enantiomers and the micelles was assumed. The retention of the solutes was effectively controlled by adding small quantities (<1.63 × 10?3 M) of the nonionic detergent Tween 20 to the mobile phase. Baseline separation was achieved by addition of 1.0 mM n-octylamine to the mobile phase; 8.14 × 10?4 M Tween 20 in phosphate buffer pH 7.0. The separation factor (α = 1.74) was unaffected by the detergent concentration in the presence of 1.0 mM n-octylamine. © 1995 Wiley-Liss, Inc. 相似文献