ObjectiveTo propose a three-degree-of-freedom model of electric wheelchair, to optimize the steering stability of the wheelchair. MethodsBased on the two degrees of freedom vehicle model and considering the influence of body inertia and lateral wind, the wheelchair roll angle was introduced to establish the three degrees of freedom steering model of wheelchair. The lateral velocity, centroid sideslip angle, yaw rate and body roll angle response of the motor angular velocity input under different working conditions were simulated and analyzed respectively. Taking KS2 electric wheelchair as an example, the wheelchair steering experiment was designed to verify the rationality and feasibility of the model, and the optimization effect of the model algorithm on the wheelchair handling and stability. ResultsThe maneuverability and stability of the electric wheelchair with three degrees of freedom model algorithm were significantly improved, and the response curve was smoother. The smaller the |V_L-V_R|/t was, the better the handling stability was when the left and right motors of the wheelchair had the same steering direction. When |V_L-V_R|/t was the same, the steering maneuverability was better on the reverse rotation of the motor, but the handling stability also decreased. ConclusionThe simulation analysis is in good agreement with the experimental results, which verifies that the model is reasonable and feasible. The model algorithm can better optimize the handling stability of electric wheelchairs, and can be generally applied to study and analyze the handling stability of different wheelchairs when they turn.

Objective To study the expression of amplified in breast cancer 1(AIB1)and ankyrin repeat domain containing11(ANKRD11/ANCO1)in human papillomavirus(HPV)positive cervical cancer and their relationship with clinicopathological characteristics and their predictive value for postoperative recurrence.Methods Cancer tissues and paracancer tissues of 94 HPV positive cervical cancer patients who visited the Third People's Hospital of Mianyang from January 2018 to January 2020 were selected,while 50 HPV negative cervical cancer tissues during this period were taken as controls.Real-time qPCR(RT-qPCR)was conducted to detect AIB1 mRNA and ANCO1 mRNA expression in cancer tissue and paracancer tissues of HPV positive cervical cancer and cancer tissue of HPV negative cervical.Pearson analysis of the correlation between AIB1 mRNA and ANCO1 mRNA expression in HPV positive cervical cancer tissues.Logistic regression analysis was used to identify the risk factors for postoperative recurrence of HPV-positive cervical cancer patients.The predictive value of AIB1 mRNA,ANCO1 mRNA,and their combination in predicting postoperative recurrence in HPV positive cervical cancer patients was analyzed by receiver operating characteristic curve.Results Compared to the adjacent tissues of HPV positive cervical cancer and cancer tissues of HPV negative cervical cancer,AIB1 mRNA(3.04±0.37 vs 0.87±0.21,1.02±0.33)in HPV positive cervical cancer tissues was higher,while ANCO1 mRNA(1.13±0.26 vs 1.91±0.35,1.82±0.36)was lower,with significant differences(t=68.499,53.137;23.649,17.434,all P<0.05).The expression of AIB1 mRNA and ANCO1 mRNA in HPV positive cervical cancer tissues showed a negative correlation(r=-0.714,P<0.001).Compared to patients with FIGO stage ⅡA～ⅡB and without lymph node metastasis,AIB1 mRNA(3.88±0.32 vs 2.04±0.41,4.46±0.33 vs 2.16±0.46)in HPV positive cervical cancer tissues with FIGO stage ⅡA and lymph node metastasis was higher,while ANCO1 mRNA(0.67±0.29 vs 1.68±0.20,0.49±0.24 vs 1.53±0.32)was lower,with significant differences(t=24.425,26.097;19.288,16.777,all P<0.001).FIGO stage ⅡA,lymph node metastasis,and high AIB1 mRNA[OR(95％CI)=1.644(1.223～2.210),1.779(1.295～2.444),1.247(1.050～1.728)]were risk factors for postoperative recurrence in HPV positive cervical cancer patients,while high ANCO1 mRNA[(OR(95％CI):0.634(0.451～0.891)]was a protective factor.The AUC(95％CI)of AIB1 mRNA and ANCO11 mRNA combined for predicting postoperative recurrence in HPV positive cervical cancer patients was 0.914(0.863～0.952),which was higher than the single indicator detection of 0.821(0.782～0.869)and 0.794(0.763～0.847),and the differences were significant(Z=4.123,4.432,all P<0.001).Conclusion The expression of AIB1 mRNA is increased and the expression of ANCO1 mRNA is reduced in HPV positive cervical cancer tissue,which are related to the occurrence and progression of cancer.The combination of the two has a high predictive value for evaluating postoperative recurrence.