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A new method is proposed for analyzing the nonlinear dynamics and stability in lane changes on highways for tractor-semitrailer under rainy weather. Unlike most of the literature associated with a simulated linear dynamic model for tractor-semitrailers steady steering on dry road, a verified 5DOF mechanical model with nonlinear tire based on vehicle test was used in the lane change simulation on low adhesion coefficient road. According to Jacobian matrix eigenvalues of the vehicle model, bifurcations of steady steering and sinusoidal steering on highways under rainy weather were investigated using a numerical method. Furthermore, based on feedback linearization theory, taking the tractor yaw rate and joint angle as control objects, a feedback linearization controller combined with AFS and DYC was established. The numerical simulation results reveal that Hopf bifurcations are identified in steady and sinusoidal steering conditions, which translate into an oscillatory behavior leading to instability. And simulations of urgent step and single-lane change in high velocity show that the designed controller has good effects on eliminating bifurcations and improving lateral stability of tractor-semitrailer, during lane changing on highway under rainy weather. It is a valuable reference for safety design of tractor-semitrailers to improve the traffic safety with driver-vehicle-road closed-loop system.

A recent pediatric-focused genome-wide association study has reported novel associations of the 20q13 and 21q22 loci with inflammatory bowel disease (IBD). We aimed to investigate these associations with Crohn's disease (CD) in Canadian children.A combined case-control and case-parent design was implemented at three pediatric gastroenterology clinics in Canada. Children less than 20 years of age with a confirmed diagnosis of CD were recruited along with controls. For a subset of the patients, biological parents were also recruited. Three single-nucleotide polymorphisms (SNPs) at the 20q13 locus and 1 SNP at the 21q22 locus were genotyped. Associations between individual SNPs and haplotypes were examined.A total of 410 cases, 415 controls, and 302 parents were studied. The mean (+/-s.d.) age for the cases was 12.3 (+/-3.2) years. Most cases were men (56.1%) who had ileocolonic disease (L3+/-L4, 52.2%) and inflammatory behavior (B1+/-B4, 87.0%) at diagnosis. Single SNP analysis showed that all 3 SNPs at the 20q13 locus were significantly associated with CD (rs2297441, P=2.24x10(-4); rs2315008, P=4.77x10(-4); rs4809330, P=6.08x10(-3)). Haplotype analysis suggested that the association signal at 20q13 resided on a common haplotype comprising the minor allele of rs2297441 (P=2.8x10(-5)). SNP rs2836878 at the 21q22 locus showed a trend for association with CD that was statistically not significant (P=0.06).Our results support an association between the 20q13 locus and CD in Canadian children. Positional cloning studies are required to further dissect the potential causative genes in the region.

Given the coupled tractor-trailer interacting with each other, road train is a complex system. The study on lateral stability of tractor trailer system is related to several fields such as multi-rigid dynamics, rigid-flexible coupling mechanics, aerodynamics. The research about the tractor-trailer lateral stability involves multi-discipline, multi-dimension, complex system, nonlinear vehicle kinematics and electronic controllability. Overview is made of the current development, method and test means about the tractor-trailer lateral stability study at home and abroad. The effects of parameters use and structure on the tractor-trailer lateral stability study are discussed. At the same time, the lateral acceleration response to step input of steering angle is also analyzed. Digital simulation algorithm of the tractor-trailer dynamics is presented, as well as typical simulation models.