Kinetic behavior of the general modifier mechanism of Botts and Morales with non-equilibrium binding

In this paper, we perform a complete analysis of the kinetic behavior of the general modifier mechanism of Botts and Morales in both equilibrium steady states and non-equilibrium steady states (NESS). Enlightened by the non-equilibrium theory of Markov chains, we introduce the net flux into discussion and acquire an expression of product rate in NESS, which has clear biophysical significance. Up till now, it is a general belief that being an activator or an inhibitor is an intrinsic property of the modifier. However, we reveal that this traditional point of view is based on the equilibrium assumption. A modifier may no longer be an overall activator or inhibitor when the reaction system is not in equilibrium. Based on the regulation of enzyme activity by the modifier concentration, we classify the kinetic behavior of the modifier into three categories, which are named hyperbolic behavior, bell-shaped behavior, and switching behavior, respectively. We show that the switching phenomenon, in which a modifier may convert between an activator and an inhibitor when the modifier concentration varies, occurs only in NESS. Effects of drugs on the Pgp ATPase activity, where drugs may convert from activators to inhibitors with the increase of the drug concentration, are taken as a typical example to demonstrate the occurrence of the switching phenomenon.Comment: 19 pages, 10 figure

Using Gamification to Support Users’ Adoption of Contextual Achievement Goals

Gamification is a promising approach for motivating and engaging users in nongame tasks. However, theoretical support on why and how gamification enhances users’ motivation or behavior is limited. Considering the concepts of goal orientation and goal structure suggested by achievement goal theory, we prescribe gamification design as purposely creating goal structures to support users’ goal adoption and achievement behaviors. This conceptual work addresses the question: what types of achievement goals can be associated with gamification design? Particularly, how can the use of gamification design help construct goal structures to support users’ goal adoption? Adapting achievement goal theory, we identify three sets of achievement goals, namely, cognitive competence, social competence, and social purpose, and develop six propositions on gamification design. Each proposition is illustrated with empirical examples from the literature. This research contributes to the theoretical advancement of gamification design and provides additional insights into the motivational design of information systems

Quality Difference Study of Six Varieties of Ganoderma lucidum with Different Origins

The quality difference of six varieties Ganoderma lucidum with different origins was investigated in this study by comparing the contents of ganoderic acid A and B, polysaccharide, and triterpenoids. The contents of ganoderic acid A and B in G. lucidum were analyzed by ultra performance liquid chromatography (UPLC). There was higher content of ganoderic acid A in G. lucidum of Dabie Mountain and Longquan. The G. lucidum from Longquan has the highest content of ganoderic acid B. The content of polysaccharide was determined by Anthrone–sulfuric acid method. The highest of polysaccharide content is G. lucidum from Liaocheng. The content of triterpenoid in G. lucidum was quantified by ultraviolet spectrophotometer at 548.1 nm using Ursolic acid as standard. The G. lucidum from Dabie Mountain has the highest content of triterpenoids. In summary, the content of ganoderic acid A and B, polysaccharide, and triterpenoids in G. lucidum with different origins are remarkably different, which may be caused by the conditions of cultivation and geographic environment

Optimization and resilience of complex supply-demand networks

Acknowledgments This work was supported by NSF under Grant No. 1441352. SPZ and ZGH were supported by NSF of China under Grants No. 11135001 and No. 11275003. ZGH thanks Prof Liang Huang and Xin-Jian Xu for helpful discussions.Peer reviewedPublisher PD