Jincai Li

© 2014 American Chemical Society.Attempts to apply artificial nano/micromotors for diverse biomedical applications have inspired a variety of strategies for designing motors with diverse propulsion mechanisms and functions. However, existing artificial motors are made exclusively of synthetic materials, which are subject to serious immune attack and clearance upon entering the bloodstream. Herein we report an elegant approach that turns natural red blood cells into functional micromotors with the aid of ultrasound propulsion and magnetic guidance. Iron oxide nanoparticles are loaded into the RBCs, where their asymmetric distribution within the cells results in a net magnetization, thus enabling magnetic alignment and guidance under acoustic propulsion. The RBC motors display efficient guided and prolonged propulsion in various biological fluids, including undiluted whole blood. The stability and functionality of the RBC motors, as well as the tolerability of regular RBCs to the ultrasound operation, are carefully examined. Since the RBC motors preserve the biological and structural features of regular RBCs, these motors possess a wide range of antigenic, transport, and mechanical properties that common synthetic motors cannot achieve and thus hold considerable promise for a number of practical biomedical uses.

Past work has shown systematic differences between Easterners' and Westerners' intuitions about the reference of proper names. Understanding when these differences emerge in development will help us understand their origins. In the present study, we investigate the referential intuitions of English- and Chinese-speaking children and adults in the U.S. and China. Using a truth-value judgment task modeled on Kripke's classic Gödel case, we find that the cross-cultural differences are already in place at age seven. Thus, these differences cannot be attributed to later education or enculturation. Instead, they must stem from differences that are present in early childhood. We consider alternate theories of reference that are compatible with these findings and discuss the possibility that the cross-cultural differences reflect differences in perspective-taking strategies.