The paper analyze the basic principle of model reference adaptive system(MRAS) algorithm. In this paper, rotor position and speed estimation algorithm of permanent magnet synchronous motor was deduced based on MRAS, and it is applied to sensorless vector control system of permanent magnet synchronous motor. Sensorless vector control system based on MRAS is built under the Matlab/Simulink environment. The simulation experiment and result analysis for the situation of motor's starting, speed mutation and load mutation are done. Simulation results prove that the sensorless vector control system of permanent magnet synchronous motor based on the algorithm of MRAS takes good control performance, and the algorithm can accurately estimate the rotor position and speed of the motor.

Histone acetylation is an important epigenetic modification, modulating the development of many tumors. However, the functions of most histone acetylation-related genes (HARGs) and their prognostic values in Ewing sarcoma (EWS) remain unclear. The current study aimed to investigate the prognostic values and potential functions of HARGs in EWS. After collecting EWS patients with mRNA sequencing data from the Gene Expression Omnibus (GEO) database and a list of HARGs from previous studies, Cox regression and Least Absolute Shrinkage and Selection Operator (LASSO) regression were performed to construct a prognostic gene signature based on HARGs. Then, four HARGs (TAF4, ATF2, HDAC2 and OGA) composed a formula to calculate risk score for each patient in the training cohort. Based on median risk score, all patients were classified into low- and high-risk group, and patients with high-risk score had a poor survival outcome (p < 0.001). The 1-, 2-,3- and 5-year AUC (0.853, 0.886,0.909and 0.833, respectively) showed the good ability of this signature to predict the prognoses of EWS patients. In addition, distinct functional enrichment and immune-related pathways were also observed in two risk groups. All results were validated in an external cohort from two dataset in GEO database. Moreover, it was found that silencing HDAC2 expression in EWS cells significantly suppressed the cell viability and migration capability. In conclusion, this is the first study to detect the prognostic values of HARGs in EWS patients, further developing a good prognostic signature based on HARGs, and HDAC2 might be an oncogene in the development of EWS.

Background and Objective: Unilateral biportal endoscopy (UBE) has been developing rapidly in coincidence with the popularization of minimally invasive spine surgery (MISS). However, the clinical outcome and invasiveness of UBE-assisted spinal surgery (UBESS) are undefined. The aim of the present study was to summarize the clinical outcome and surgical invasiveness of UBE for the treatment of various spinal degenerative diseases in a single center to validate the safety and application value of UBESS. Methods: Included in this study were 105 patients who received UBESS from November 2021 to June 2022 in our center. All patients were followed up postoperatively for at least 12 months. All basic information was recorded to depict the demographic and surgical variables. Clinical outcomes were assessed in terms of the operation time, complications, days of hospital stay, total blood loss, intraoperative blood loss, postoperative drainage volume, hidden blood loss, biochemical changes associated with surgical injury, comparison of the visual analogue scale (VAS) for back and leg pain, Japanese Orthopedic Association (JOA) scores for cervical diseases at preoperative and postoperative stage, as well as Oswetry Disability Index (ODI), and modified MacNab scores one year after treatment. Results: Of the 105 included patients, 68 patients were with single-level lumbar degenerative diseases, 22 with two-level diseases, two with three-level diseases, 10 with single-level isthmic spondylolisthesis, and three with single-level cervical spondylotic radiculopathy. UBE was performed by using five surgical approaches. The operation time, days of hospital stay, blood loss, postoperative immobilization time and prognosis were all estimated in consideration of the surgical approaches and the number of operated segments. The mean operation time ranged from 80 min to 214 min for single-level spinal diseases, and 112 min to 330 min for two-level ones. Total blood loss was higher in multilevel spinal surgery and single-level UBE-assisted lumbar interbody fusion+discectomy (ULIFD). The postoperative immobilization duration was between 0.5 and 2 days for single level spinal diseases, 1 and 3 days for 2-level diseases, fewer than 2 days for three-level diseases, and 1.5–12 days for isthmic spondylolisthesis (IS). The VAS and ODI for lumbar diseases decreased significantly and the JOA scores for cervical diseases improved after operation. The satisfaction rate was 89.70%, 85.71%, 90.00%, 66.67%, and 90.00% for the five surgical approaches respectively. Conclusions: UBESS has proved to be a safe, reliable and minimally invasive option for spinal degenerative diseases, with significant benefits of pain control, rapid functional recovery, short hospitalization, and early rehabilitation. However, postoperative hidden blood loss should be put under the careful management when performing UBESS.

Study Design: Retrospective case‒control study Objectives: This study aimed to report the effects of surgical intervention on spinal stability recovery and to assess the long-term outcomes of children and adolescents with lumbar tumors. Methods: From January 2016 to June 2021, 42 pediatric patients with lumbar tumors were selected and separated into different groups based on the surgical method used (total en bloc resection (TER) group, n = 21; piecemeal resection (PR) group, n = 21; titanium mesh (TM) group n = 23; artificial vertebrae (AV) group n = 19). The clinicopathological characteristics, treatments and related outcomes were described in detail and compared between groups, with P value ≤.05 indicating statistically significant differences. Results: The average follow-up duration was 24.89 months, and the mean age was 14.89 ± 2.41 years. There were no significant differences in the mean operation time, average blood loss, complication rate, or length of hospital stay between the groups. The ODI, VAS and JOA scores at the final follow-up (FF) were elevated after surgery in all groups. The FF local angular drift (LOD) and lumbar angular drift (LUD) were greater in the TM group than in the AV group ( P = .03, P = .001). Conclusions: After surgery, pediatric patients with lumbar tumors can obtain satisfactory spinal stability, effective relief of pain symptoms and substantial improvements in neurological function. There was no significant difference in the invasiveness, safety or timeliness between the 2 surgical methods, so TER is recommended due to its low postoperative recurrence rate and good local control. Spinal fusion in the AV group resulted in better spinal stability.

With the rapid development of the economy and power electronics, permanent magnet synchronous motor (PMSM) is widely used in various fields, vigorously promoting the development of China’s equipment manufacturing industry in the era, and the related topics have become a hot topic nowadays. However, permanent magnet synchronous motor control systems are characterized by non-linearity and time-varying parameters, which pose a threat to the reliability of practical engineering applications. Based on this, this paper combines an improved grey wolf optimization (GWO) algorithm with a PID controller to establish a general model of a permanent magnet synchronous motor speed control system, including control, drive and feedback modules, to achieve accurate control of the running speed of a permanent magnet synchronous motor. Finally, the simulation model of space vector pulse width modulation (SVPWM) based system is built by MATLAB/SIMULINK, and the simulation and analysis of corresponding parameters are completed given a definite input signal.