Elevator block brake structural optimization design based on an approximate model.

An Aquila optimizer-back propagation (AO-BP) neural network was used to establish an approximate model of the relationship between the design variables and the optimization objective to improve elevator block brake capabilities and achieve a lightweight brake design. Subsequently, the constraint conditions and objective functions were determined. Moreover, the multi-objective genetic algorithm optimized the structural block brake design. Finally, the effectiveness of the optimization results was verified using simulation experiments. The results demonstrate that the maximum temperature of the optimized brake wheel during emergency braking was 222.09°C, which is 36.71°C lower than that of 258.8°C before optimization, with a change rate of 14.2%. The maximum equivalent stress after optimization was 246.89 MPa, 28.87 MPa lower than that of 275.66 MPa before optimization, with a change rate of 10.5%. In addition, the brake wheel mass was reduced from 58.85 kg to 52.40 kg, and the thermal fatigue life at the maximum equivalent stress increased from 64 times before optimization to 94 times after optimization.

Association of Enterovirus 71 encephalitis with the interleukin-8 gene region in Chinese children.

The study was performed in 36 Chinese patients with Enterovirus 71 (EV71) encephalitis and 141 patients with EV71-related hand, foot and mouth disease (HFMD) without encephalitis. Genotyping was determined by polymerase chain reaction- restriction fragment length polymorphism. Patients with EV71 encephalitis had a significantly higher frequency of interleukin-8 (IL-8)-251TT genotype than patients with EV71-related HFMD without encephalitis (55.6% vs 31.2%, p = 0.023). The frequency of IL-8-251T alleles was significantly higher among patients with EV71 encephalitis than in patients with EV71-related HFMD without encephalitis (72.2% vs 58.9%, odds ratio 1.8, 95% confidence interval 1.0-3.2, p = 0.038). There were significant differences in gender, age, fever days, white blood cell count, C-reactive protein and blood glucose concentration and IL-8 levels among genotypes of IL-8-251A/T in EV71-infected patients, but no significant differences in alanine or aspartate aminotransferase, creatine kinase-myocardial isozyme and cerebrospinal fluid in patients with EV71 encephalitis. These findings suggest that the IL-8-251T allele is associated with susceptibility to EV71 encephalitis in Chinese patients.

Sonographic detection of unilateral hip dislocation in a spica cast after closed reduction for developmental dysplasia of the hip.

OBJECTIVES: To determine the value of sonography for evaluating unilateral hip dislocation in a spica cast after closed reduction for developmental dysplasia of the hip. METHODS: Seventy-three cases of unilateral hip dislocation were detected by sonography after closed reduction and monitored through the perineal opening of the cast during follow-up. The transinguinal approach was used first to determine the position of the femoral head. Then a sonogram of the bilateral hips was obtained by transverse scanning on the lower margin of the pubic symphysis. To determine the status of the affected femoral head, a bilateral comparison of the femoral head positions was made by measuring the horizontal distance from the medial rim of each femoral head to a center line through the pubic symphysis. RESULTS: In all 73 cases, the femoral head position after reduction could be identified by sonography. With the transinguinal approach, the reduction was successful in 69 cases and unsuccessful in 4. On the sonograms of the bilateral hips, the dislocated femoral heads were repositioned in the acetabular fossa in the successful cases and redislocated posterolaterally in the unsuccessful cases. Among the successful cases, the position differences were less than 2 mm in 61, 3 to 4 mm in 7, and 5 mm in 1. In the unsuccessful cases, the positions of the bilateral hips were asymmetric; the differences were indecipherable after an unsuccessful first reduction but were 3 to 5 mm after a successful second reduction. During follow-up, the differences were never greater than 2 mm in the cases with initial differences of less than 2 mm and gradually decreased to less than 2 mm in those with initial differences of greater than 2 mm. CONCLUSIONS: Sonography can be considered as the first imaging tool for evaluating the effect of closed reduction for developmental dysplasia of the hip.