Browsing by Author "Zhang, Jun"
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- Endothelial Cell Capture of Heparin-Binding Growth Factors under FlowZhao, Bing; Zhang, Changjiang; Forsten-Williams, Kimberly; Zhang, Jun; Fannon, Michael (PLOS, 2010-10)Circulation is an important delivery method for both natural and synthetic molecules, but microenvironment interactions, regulated by endothelial cells and critical to the molecule's fate, are difficult to interpret using traditional approaches. In this work, we analyzed and predicted growth factor capture under flow using computer modeling and a three-dimensional experimental approach that includes pertinent circulation characteristics such as pulsatile flow, competing binding interactions, and limited bioavailability. An understanding of the controlling features of this process was desired. The experimental module consisted of a bioreactor with synthetic endothelial-lined hollow fibers under flow. The physical design of the system was incorporated into the model parameters. The heparin-binding growth factor fibroblast growth factor-2 (FGF-2) was used for both the experiments and simulations. Our computational model was composed of three parts: (1) media flow equations, (2) mass transport equations and (3) cell surface reaction equations. The model is based on the flow and reactions within a single hollow fiber and was scaled linearly by the total number of fibers for comparison with experimental results. Our model predicted, and experiments confirmed, that removal of heparan sulfate (HS) from the system would result in a dramatic loss of binding by heparin-binding proteins, but not by proteins that do not bind heparin. The model further predicted a significant loss of bound protein at flow rates only slightly higher than average capillary flow rates, corroborated experimentally, suggesting that the probability of capture in a single pass at high flow rates is extremely low. Several other key parameters were investigated with the coupling between receptors and proteoglycans shown to have a critical impact on successful capture. The combined system offers opportunities to examine circulation capture in a straightforward quantitative manner that should prove advantageous for biologicals or drug delivery investigations.
- Explaining the outcomes of social gamification: A longitudinal field experimentZhang, Jun; Jiang, Qiqi; Zhang, Wenping; Kang, Lele; Lowry, Paul Benjamin; Zhang, Xiong (Taylor & Francis, 2023)Social gamification, which allows technology users to interact with each other in gamified tasks, has drawn increasing interest due to its effectiveness in facilitating users’ game engagement and task efforts. In social gamification, users can compete or cooperate with other users or teams to complete game tasks and achieve game goals. However, it remains unclear how various social interaction mechanisms (SIMs), such as cooperation, interpersonal competition, and intergroup competition, influence gamification outcomes when they are separately or jointly implemented. In addition, the effects of SIMs on experiential and instrumental gamification outcomes have not been well differentiated. In this study, we systematically investigate the influences of these fundamental SIMs, as well as the possible interaction effects among them, on fitness app users’ game engagement and fitness behavior. Using a fitness app custom-developed for the Chinese market, Fitness Castle, we conducted a longitudinal field experiment to test our proposed model and hypotheses. The results indicate that when separately implemented, cooperation and interpersonal competition can lead to differential instrumental gamification outcomes in the fitness context. We also systematically compare the differential gamification outcomes when cooperation, interpersonal competition, and intergroup competition are combined in various coopetition settings. Our study offers a theory-based framework and design principles for social gamification. Our findings help practitioners better design SIMs in their gamified technologies with the purpose of achieving optimal experiential and instrumental gamification outcomes simultaneously.