Abstract The mechanisms involved in the fast growth of Angiostrongylus cantonensis from fifth-stage larvae (L5) to female adults and how L5 breaks through the blood-brain barrier in a permissive host remain unclear. In this work, we compared the transcriptomes of these two life stages to identify the main factors involved in the rapid growth and transition to adulthood. RNA samples from the two stages were sequenced and assembled de novo. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses of 1,346 differentially expressed genes between L5 and female adults was then undertaken. Based on a combination of analytical results and developmental characteristics, we suggest that A. cantonensis synthesizes a large amount of cuticle in L5 to allow body dilatation in the rapid growth period. Products that are degraded via the lysosomal pathway may provide sufficient raw materials for cuticle production. In addition, metallopeptidases may play a key role in parasite penetration of the blood-brain barrier during migration from the brain. Overall, these results indicate that the profiles of each transcriptome are tailored to the need for survival in each developmental stage.

Abstract Clearance always exists in actual joint due to many uncertainties such as machining tolerance, assemblage and load deformation. The main purpose of this paper is to propose a computational and experimental study on the dynamic characteristics of a planar multibody mechanical system with joint clearance. For this purpose, a suitable dynamic model plays a crucial role in simulating the overall performance of the mechanical systems. To describe the interaction in joints with clearance, the normal contact model is established based on the Lankarani-Nikravesh contact force model, while the friction effect is conducted using the Coulomb friction model. Meanwhile, the experimental platform is set up and a planar mechanism with clearance joint is employed as a model mechanism. The obtained results demonstrate that the dynamic behavior of the mechanism can be effectively predicted by this method. Furthermore, the effects of the rotational speed of crank shaft and size of joint clearance on the dynamic response of the mechanism are investigated.