The therapeutic action of bone marrow-derived mesenchymal stem cells (BMSCs) in acute kidney injury (AKI) has been reported by several groups. However, recent studies indicated that BMSCs homed to kidney tissues at very low levels after transplantation. The lack of specific homing of exogenously infused cells limited the effective implementation of BMSC-based therapies. In this study, we provided evidence that the administration of BMSCs combined with muscone in rats with gentamicin-induced AKI intravenously, was a feasible strategy to drive BMSCs to damaged tissues and improve the BMSC-based therapeutic effect. The effect of muscone on BMSC bioactivity was analyzed in vitro and in vivo. The results indicated that muscone could promote BMSC migration and proliferation. Some secretory capacity of BMSC still could be improved in some degree. The BMSC-based therapeutic action was ameliorated by promoting the recovery of biochemical variables in urine or blood, as well as the inhibition of cell apoptosis and inflammation. In addition, the up-regulation of CXCR4 and CXCR7 expression in BMSCs could be the possible mechanism of muscone amelioration. Thus, our study indicated that enhancement of BMSCs bioactivities with muscone could increase the BMSC therapeutic potential and further developed a new therapeutic strategy for the treatment of AKI.
Articulated tracked vehicles are used as special off-road transportation vehicles, and their mobility is gaining more attention now than before. As an important evaluation indicator of the mobility of articulated tracked vehicles, steering performance receives wide attention in particular. Most of the present studies focus on the planar steering performance; few studies employing current models concentrate on the slope steering performance of articulated tracked vehicles. To address this research gap, this study proposes a dynamic modeling method for analyzing the slope steering performance of articulated tracked vehicles. A kinematic model of a vehicle is initially constructed to analyze its kinematic characteristics during slope steering; these characteristics include velocity and acceleration. A dynamic model of a vehicle is then developed to analyze its mechanical characteristics during slope steering; these characteristics include vertical loads, driving forces, and driving moments of tracks. The created dynamic model is then applied to analyze the slope steering performance of a specific articulated tracked vehicle. A mechanical-control united simulation model and an actual test of an articulated tracked vehicle are suggested to verify the established steering model. Comparison results show the effectiveness of the proposed dynamic steering model.
The steering performance is one of the major concerns in special engineering vehicle fields. This study aims to investigate the steering performance of an articulated tracked vehicle. An improved dynamic steering model for an articulated tracked vehicle is proposed when considering the shear stress–shear displacement relation of the soil at the track–ground interface. In this model, the mechanical, kinematic and dynamic models of the articulated unit are constructed to evaluate the movement performance of the articulated unit, and the kinematic and dynamic models of the front vehicle and the rear vehicle are developed to evaluate the steering performance. The created dynamic model is then applied to analyse the steering performance of a specific articulated tracked vehicle. A mechanically controlled united simulation model and actual tests of an articulated tracked vehicle are utilized to verify the established steering model. The results of the comparisons show the effectiveness of the proposed dynamic steering model.
Purpose
The paper aims to explore the effect of problem-based learning (PBL) embedding degree and education level on individual perception, as well as the moderating effect of nationality.
Design/methodology/approach
The paper first conceptualizes PBL embedding degree which means the extent of applying PBL. It takes an empirical study on an international MBA class in one of the first-class universities in China. An investigation is taken with the designed “PBL-based Cognitive Perception Scale” and an Ordered Probit Model is constructed.
Findings
The findings of this study are as follows: PBL embedding degree has a significant effect on the cognitive perception of student, which varies in different dimensions; the educational level of international student positively affects the cognitive perception toward PBL; and nationality may moderate the relationship between the PBL embedding degree and individual perception.
Originality/value
The paper replenishes the investigation and application of Bloom’s Taxonomy of Learning. By conceptualizing PBL embedding degree, the paper extends the research perspectives of PBL and proposes a subjective method on the evaluation of PBL. The paper also may provide a guidance for PBL curriculum design with sustainable development of education.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.