Edward S. Yeung

Single nanoparticle tracking (SPT) is a unique and powerful tool to investigate the interaction between nanoparticles and cells, which is of great importance for nanotechnology applications in biom... Description

Diversity, a major societal force that exerts an important influence on contemporary workplaces, may play a role in shaping present-day workers’ psychological contracts. In two studies, we explored diversity as an ideological commitment in psychological contracts and its impacts on workers and organizations. In Study 1, a three-wave longitudinal study following workers from pre- to post-hire, organizations’ use of diversity recruitment was positively associated with job-seekers’ perceptions that ideological diversity climate promises were made pre-employment. In addition, we found that subsequent perceptions of breaching these promises have negative effects on worker attitudes and behaviours above and beyond the consequences of traditional (i.e., transactional and relational) psychological contract breach. Unexpectedly, fulfilment and breach of ideological diversity climate promises were more weakly related to racial minority than majority group workers’ attitudes and behaviours. In Study 2, using both between- and within-person experimental designs, we largely replicate this counter-intuitive moderating effect and uncover that racial minority versus majority workers’ differential reactions can be explained by their prior experiences with racial discrimination. Our work substantiates that diversity is an important ideological commitment and provides novel insights as to the mechanisms and consequences of ideology for workers’ psychological contracts.

Summary: Pride, a discrete emotion that drives the pursuits of achievement and status, is crucial to consider in leadership contexts. Across three studies, we explored how leaders' experiences of authentic and hubristic pride were associated with their leadership behaviors. In Study 1, a field study of leader–follower dyads, leader trait authentic pride was associated with the use of more effective (i.e., consideration and initiating structure) and fewer ineffective (i.e., abusive supervision) leadership behaviors, and hubristic pride was associated with more abusive behaviors. In Study 2, a daily diary study, on days when leaders experienced more authentic pride than usual, they used more effective leadership behaviors than usual, whereas on days when leaders experienced more hubristic pride than typical, they were more likely to engage in abusive supervision than typical. In Study 3, a scenario‐based experiment, leaders who experienced more authentic pride in response to our experimental manipulation were more likely to intend to use effective leadership behaviors. In contrast, those who experienced more hubristic pride were less likely to use these behaviors and more likely to intend to be abusive. Overall, this work highlights the importance of pride for leadership processes and the utility of examining discrete and self‐conscious emotions within organizations.

Investigation of the cellular internalization processes of individual nanoparticles (NPs) is of great scientific interest with implications to drug delivery and NP biosafety. Herein, by using dual-channel polarization darkfield microcopy (DFM) and single gold nanorods (AuNRs) as orientation probes, we developed a method that is capable of monitoring AuNR orientation dynamics during its transmembrane process. With annular oblique illumination and a birefringent prism to split AuNR plasmonic scattering into two channels of orthogonal polarizations, the AuNR azimuth and polar angles are obtained from their intensity difference and intensity sum. By placing the focal plane of the microscope objective at the elevated cell sidewall rather than at the flat cell top, interference from cellular background is reduced and the signal-to-noise ratio of AuNR orientation sensing is improved significantly, especially for AuNRs inserting into the membrane at a large out-of-plane angle. As a result, we were able to capture the complete membrane-crossing dynamics of single AuNRs. This powerful method could be utilized to obtain valuable insights on NP endocytosis mechanisms of various cells.

Molecular crystallization typically singles out a specific conformation, or a set of conformations that are identical over large parts and may show some flexibility, from a mixture of equilibrating conformations in solution. To critically evaluate the selectivity of this process, human lactate dehydrogenase isozyme 1 (LDH-1) microcrystals were separately dissolved and subsequently assayed inside capillaries with electrophoretically mediated microanalysis (EMMA) at both the ensemble and the single-molecule level. While fragments from the same crystal exhibited identical enzyme activities, different crystals, even when grown from the same drop of mother liquor, showed markedly different activities. Activities of individual molecules from a crystal were found to be essentially identical, whereas molecules obtained directly from solution showed a 4-fold variation in activity. Furthermore, after storage at 37 °C, the distribution of single-molecule LDH activities from solutions of individual crystals broadened and approached that of LDH obtained from the original solution. X-ray crystallography also showed distinct conformations for single microcrystals and confirms that crystallization properly selects even small conformational variants of proteins and that the slow equilibration to multiple stable conformations in solution is responsible for the observed single-molecule heterogeneity.