RESUMEN
Due to the global coverage and real-time access advantages of the Tracking and Data Relay Satellite System (TDRSS), the demonstration platform based on TDRSS can satisfy the new technology verification and demonstration needs of the space information network (evolution from sensorweb). However, the comprehensive evaluation research of this demonstration platform faces many problems: complicated and diverse technical indicators in various areas, coupling redundancy between indicators, difficulty in establishing the number of indicator system layers, and evaluation errors causing by subjective scoring. Concerning the difficulties, this paper gives a method to construct this special index system, and improves the consistency of evaluation results with Analytic Hierarchy Process in Group Decision-Making (AHP-GDM). A comprehensive evaluation index system including five criterions, 11 elements, more than 30 indicators is constructed according to the three-step strategy of initial set classification, hierarchical optimization, and de-redundancy. For the inconsistent scoring of AHP-GDM, a high-speed convergence consistency improvement strategy is proposed in this paper. Moreover, a method for generating a comprehensive judgment matrix (the aggregation of each judgment matrix) aggregation coefficient is provided. Numerical experiments show that this strategy effectively improves the consistency of the comprehensive judgment matrix. Finally, taking the evaluation of TDRSS development as an example, the versatility and feasibility of the new evaluation strategy are demonstrated.
RESUMEN
G protein-gated inwardly rectifying potassium (GIRK) channels play a significant role in physiopathology by the regulation of cell excitability. This regulation depends on the K+ ion conduction induced by structural constrictions: the selectivity filters (SFs), helix bundle crossings (HBCs), and G-loop gates. To explore why no permeation occurred when the constrictions were kept in the open state, a 4-K+-related occupancy mechanism was proposed. Unfortunately, this hypothesis was neither assessed, nor was the energetic characteristics presented. To identify the permeation mechanism on an atomic level, all-atom molecular dynamic (MD) simulations and a coupled quantum mechanics and molecular mechanics (QM/MM) method were used for the GIRK2 mutant R201A. It was found that the R201A had a moderate conductive capability in the presence of PIP2. Furthermore, the 4-K+ group of ions was found to dominate the conduction through the activated HBC gate. This shielding-like mechanism was assessed by the potential energy barrier along the conduction pathway. Mutation studies did further support the assumption that E152 was responsible for the mechanism. Moreover, E152 was most probably facilitating the inflow of ions from the SF to the cavity. On the contrary, N184 had no remarkable effect on this mechanism, except for the conduction efficiency. These findings highlighted the necessity of a multi-ion distribution for the conduction to take place, and indicated that the K+ migration was not only determined by the channel conductive state in the GIRK channel. The here presented multi-ion permeation mechanism may help to provide an effective way to regulate the channelopathies.