Flagellated Janus particles for multimodal actuation and transport

Catalytic Janus particles rely on chemical decomposition to self-propel and have displayed enormous potential for targeted drug delivery and cellular penetration. Catalytic propulsion mechanisms are limiting, however, with fuel requirements and specialized fluid properties being necessary to achieve propulsion. We have improved the dynamic propulsion of catalytic Janus particles by functionalizing flagellar filaments to one of their hemispheres. Flagellated Janus particles, torqued by rotating magnetic fields, swim along their rotation axis using the explicit chirality and flexibility of flagella, mimicking flagellar rotation of live bacteria. Depending on the working fluid, flagellated Janus particles can propel using either catalytic or swimming propulsion. We demonstrate experimentally that flagellated Janus particles behave predictably under the two actuation modes and can precisely follow trajectories under closed-loop feedback control. Flagellated Janus particles were demonstrated to swim in both Newtonian and shear-thickening fluids. These are the first Janus particles developed that can be propelled interchangeably between catalytic and flagellar swimming propulsion, allowing two distinct propulsion mechanisms for future use within in vivo operations.     

Competing explanations for knowledge exchange: Technology sharing within the globally dispersed R&D of the multinational enterprise

This paper explores five competing theories for technological knowledge sharing within the globally dispersed R&D function of the multidivisional, multinational firm. These five broad explanations for why a knowledge transaction occurs are: (1) economic, (2) technological, (3) organizational, (4) geographic, and (5) sociological. In addition to occurrence, likelihood of knowledge exchange success prompted by various explanations is considered. Ultimately the determination of which argument—or combination of arguments—offers the greatest explanatory power for the sharing of intermediate technological knowledge may be answered empirically.     

Book reviews

Henry Holt & Co.     

Analysis of coaching science research published from 1970-2001

The study followed a four-phase design. In Phase I an exhaustive search was conducted for all English language coaching research published in journals from 1970 to 2001. In Phase II, copies of the research were obtained. An expert panel conducted a manual search and a review in Phase III to address validity. Analysis of the research was completed in Phase IV (Culver Gilbert, & Trudel, 2003; Silverman & Skonie, 1997). Over 1,100 articles were reviewed, and 610 met the inclusion criteria. Selected findings include: (a) a relatively low mean spread across many journals, (b) a focus on coaching behavior using quantitative methodologies, and (c) a primary emphasis on team sports in school contexts.