After the production of the gradient coil of the magnetic resonance imaging system, electromagnetic field testing is required to verify whether the assembly accuracy meets the electromagnetic field requirements. Since the passive magnetic field B _z satisfies the Laplace ^,s equation and is a harmonic function, and according to the extreme value principle of harmonic function, the maximum or minimum values of B _z can only appear on the boundaries, so the observation points of the magnetic field are generally selected on the surface of the spherical imaging area. For superconducting magnets used for human body magnetic resonance imaging, a spherical area with a center diameter of 40~50 cm is generally selected as the shimming target area. Only the field value of the target area needs to be measured, and the spherical harmonic coefficients obtained after data processing are used to determine the magnetic field performance of the gradient coil. There are many testing principles and methods for electromagnetic fields, so there is no unified way and method in the field of commercial applications. This article is based on the Gauss-Legendre numerical integration, measures and analyzes the magnetic field performance of gradient coils by building a data acquisition system, and this article applies numerical analysis methods to calculate the spherical harmonic coefficients of the magnetic field using discrete test data, providing a feasible method for the production and testing of gradient coils.
Magnetic Resonance Imaging/methods* ; Magnetic Fields ; Electromagnetic Fields ; Equipment Design

BACKGROUND:Developmental dysplasia of hip refers to the deformity of acetabulum and proximal femur,which can lead to hip instability and hip osteoarthritis. Periacetabular osteotomy is the main treatment for non-terminal developmental dysplasia of hip in adolescents and adults. Pelvic inclination plays an important role in biomechanics of hip joint,which determines the stress direction of hip joint. In hip joint diseases,pelvic compensatory tilt can occur to minimize the abnormal stress of hip joint.OBJECTIVE:To observe whether periacetabular osteotomy changes pelvic sagittal tilt in patients with developmental dysplasia of hip,and to investigate the effect of acetabular covering on pelvic sagittal tilt.METHODS:A retrospective analysis was performed on 29 patients who underwent periacetabular osteotomy due to developmental dysplasia of hip in West China Hospital of Sichuan University from August 2019 to June 2022. Anteroposterior X-rays of the standing pelvis were collected before and 6 months after surgery. The pelvic tilt parameters,including the lateral center-edge angle,pubic symphysis to sacroiliac joint distance,pubic symphysis to sacroiliac joint midline distance,sacrofemoral-pubic angle,and pelvic tilt,were measured. Hip functions of all patients were assessed by hip disability and osteoarthritis score and Harris score before and 6 months after surgery.RESULTS AND CONCLUSION:(1) The lateral center-edge angle,pubic symphysis to sacroiliac joint midline distance,and sacrofemoral-pubic angle were significantly increased 6 months postoperatively compared to preoperative values (P<0.05). Tonnis angle and pelvic tilt were significantly decreased (P<0.05). There was no significant difference in pubic symphysis to sacroiliac joint distance between preoperative and postoperative measurements (P>0.05). (2) The hip disability and osteoarthritis scores and Harris scores were significantly increased 6 months after operation (P<0.01). (3) It is indicated that periacetabular osteotomy surgery can significantly improve acetabular coverage and the pelvis showed significant anteversion changes in patients with developmental dysplasia of hip.

BACKGROUND:Developmental dysplasia of hip refers to the deformity of acetabulum and proximal femur,which can lead to hip instability and hip osteoarthritis. Periacetabular osteotomy is the main treatment for non-terminal developmental dysplasia of hip in adolescents and adults. Pelvic inclination plays an important role in biomechanics of hip joint,which determines the stress direction of hip joint. In hip joint diseases,pelvic compensatory tilt can occur to minimize the abnormal stress of hip joint.OBJECTIVE:To observe whether periacetabular osteotomy changes pelvic sagittal tilt in patients with developmental dysplasia of hip,and to investigate the effect of acetabular covering on pelvic sagittal tilt.METHODS:A retrospective analysis was performed on 29 patients who underwent periacetabular osteotomy due to developmental dysplasia of hip in West China Hospital of Sichuan University from August 2019 to June 2022. Anteroposterior X-rays of the standing pelvis were collected before and 6 months after surgery. The pelvic tilt parameters,including the lateral center-edge angle,pubic symphysis to sacroiliac joint distance,pubic symphysis to sacroiliac joint midline distance,sacrofemoral-pubic angle,and pelvic tilt,were measured. Hip functions of all patients were assessed by hip disability and osteoarthritis score and Harris score before and 6 months after surgery.RESULTS AND CONCLUSION:(1) The lateral center-edge angle,pubic symphysis to sacroiliac joint midline distance,and sacrofemoral-pubic angle were significantly increased 6 months postoperatively compared to preoperative values (P<0.05). Tonnis angle and pelvic tilt were significantly decreased (P<0.05). There was no significant difference in pubic symphysis to sacroiliac joint distance between preoperative and postoperative measurements (P>0.05). (2) The hip disability and osteoarthritis scores and Harris scores were significantly increased 6 months after operation (P<0.01). (3) It is indicated that periacetabular osteotomy surgery can significantly improve acetabular coverage and the pelvis showed significant anteversion changes in patients with developmental dysplasia of hip.

In order to understand the prevalence of Akabane disease(AKAD)in Guizhou Province and the molecular characteristics of the isolates,the whole-genome sequence of a strain of Akabane virus(AKAV)from a bovine AKAD-positive sample was determined and analyzed.The genotype and genetic variation of the strain were also explored.Based on the conserved S sequence,a fluores-cence quantitative PCR(qPCR)detection method was established and applied for the investigation of AKAV infection status in four large-scale beef cattle farms of Guizhou.Results showed that the S,M and L fragments of the bovine strain were highly homologous to the Tianjin strain(TJ2016/China/2016)and the Australian strain(JaLAB39/Australia/1959),where they were in the same evolutionary branch and belonged to genotype Ⅱ.Sensitivity assay found that the lowest detection limit was 2.5 X 101 copies/μL.Specificity assay showed the established method detected only AKAV with no amplification on bovine bluetongue virus(BLUV),Pasteurella multocida(PM),bovine infectious rhinotracheitis virus(IBRV)and bovine Mycoplasma bovis.The variation coefficients of inter-and intra batches in the repeatability test were both lower than 2.26％.These findings illus-trated that the established qPCR method had high sensitivity,good specificity and repeatability.A total of 298 serum samples from 4 large-scale beef cattle farms in Qianxi City and Huangping County of Guizhou Province were collected and tested for AKAV by the method.Out of 298 sam-ples,25 positive samples(25/298)were detected as positive with a positive rate of 8.39％.In sum-mary,this work provided the reference data for a deep understanding of the molecular prevalence of AKAV in Guizhou Province and laid foundation for the prevention and control of AKAD.

Objective:To investigate the relationship between cancer node status identified after radical resection and patterns of recurrence in stage Ⅱ/Ⅲ gastric cancer patients for developing personalized follow-up plans in node-positive patients.Methods:A retrospective analysis was conducted on 706 stage Ⅱ/Ⅲ gastric cancer patients who underwent curative intent surgery at Henan Cancer Hospital from Sep 2015 to Sep 2018. Patients were categorized into node-positive (TDs +) and node-negative (TDs -) groups based on their cancer node status. Clinical-pathological characteristics and recurrence patterns were compared between the groups to formulate an optimized follow-up plan. Results:Among the patients, there were 112 TDs + and 594 TDs - cases. TDs - patients exhibited significantly better overall survival and disease-free survival rates at 1 and 3 years compared to the TDs + group (92.4%,72.2% vs. 79.4%,38.8%;87.9%,68.6% vs. 66.7%,35.9%, all P<0.05). The cumulative recurrence rates of peritoneal and distant metastases were higher in TDs + patients compared to TDs - patients, with statistical significance (33.0% vs. 14.5%,21.4% vs. 10.8%, χ 2=21.285,8.851 all P<0.05). TDs + patients experienced significantly earlier median time to distant metastasis compared to TDs - patients (9.0 months vs. 15.4 months , Z=-2.294 P=0.022). The risk of peritoneal metastasis recurrence was higher in the TDs + group, showing a bimodal recurrence pattern at 8.5 and 15.0 months post-surgery. TDs + patients also had a higher risk of distant metastasis recurrence, with a single peak at 6 months. Conclusion:Postoperative recurrence patterns differ between TDs + and TDs - patients, and an optimized follow-up plan can enhance early detection of recurrence.

ObjectiveTo investigate the effect of alcohol extract of Oroxylum indicum （MHD-80） on reducing uric acid （UA） and protecting the kidney in the hyperuricemia （HUA） model in vivo. MethodPotassium oxazine （350 mg·kg^-1） and adenine （80 mg·kg^-1） were used to construct an HUA model of mice in vivo to evaluate the mechanism related to UA reduction and the protective effect of renal function of MHD-80. Seventy male ICR mice were randomly divided into seven groups， including the normal group， model group， allopurinol group （5 mg·kg^-1）， febusotan group （5 mg·kg^-1）， and MHD-80 low-， medium-， and high-dose groups （3， 6， 12 mg·kg^-1）， with 10 in each group. Except for the normal group， the other groups were given intragastric administration of potassium oxazine and adenine for 14 consecutive days to establish the HUA model. On the 8^th to 14^th day after modeling， each group was given corresponding drugs by intragastric administration， once a day. 1 h after the last administration， blood was collected from the eyeballs， and kidney and liver tissues of mice were collected. Serum levels of UA， urea nitrogen （BUN）， and creatinine （Cr） and liver activity of xanthine oxidase （XOD） were determined by enzyme colorimetry. Serum contents of tumor necrosis factor-α （TNF-α） and interleukin-1β （IL-1β） were determined by enzyme-linked immunosorbent assay （ELISA）. Hematoxilin-eosin （HE） staining was used to observe the pathological changes in kidney tissues. The protein expression levels of ATP-binding box transporter G2 （ABCG2） and glucose-facilitating transporter 9 （GLUT9） in kidney tissues were detected by Western blot. ResultIn vivo experiment shows that compared with the normal group， the serum levels of UA， Cr， BUN， inflammatory factors TNF-α， IL-1β， and liver XOD activity in the serum of mice in the model group were significantly increased （P<0.05， P<0.01）， and the expression of GLUT9 in kidney tissues was significantly up-regulated （P<0.05）. ABCG2 protein expression was significantly down-regulated （P<0.05）， and renal injury was obvious. Compared with the model group， the levels of UA， BUN， Cr， TNF-α， IL-1β， and liver XOD activity in the serum of mice in the high-dose group of MHD-80 were decreased to different degrees （P<0.05， P<0.01）， GLUT9 protein expression was significantly down-regulated （P<0.01）， ABCG2 protein expression was significantly up-regulated （P<0.05） in the high-dose group of MHD-80， and the degree of renal injury was reduced. ConclusionMHD-80 has certain uric acid reduction， anti-inflammatory， and anti-renal injury effects， which are related to inhibiting XOD activity and regulating the expression of ABCG2 and GLUT9 uric acid transporter.

Pulmonary blast injury has become the main type of trauma in modern warfare, characterized by externally mild injuries but internally severe injuries, rapid disease progression, and a high rate of early death. The injury is complicated in clinical practice, often with multiple and compound injuries. Currently, there is a lack of effective protective materials, accurate injury detection instrument and portable monitoring and transportation equipment, standardized clinical treatment guidelines in various medical centers, and evidence-based guidelines at home and abroad, resulting in a high mortality in clinlcal practice. Therefore, the Trauma Branch of Chinese Medical Association and the Editorial Committee of Chinese Journal of Trauma organized military and civilian experts in related fields such as thoracic surgery and traumatic surgery to jointly develop the Clinical treatment guideline for pulmonary blast injury ( version 2023) by combining evidence for effectiveness and clinical first-line treatment experience. This guideline provided 16 recommended opinions surrounding definition, characteristics, pre-hospital diagnosis and treatment, and in-hospital treatment of pulmonary blast injury, hoping to provide a basis for the clinical treatment in hospitals at different levels.

Objective:To establish a nomogram to predict overall survival of patients with stage Ⅰ-Ⅲ gastric cancer (GC) based on preoperative inflammatory markers.Methods:Clinicopathological and follow-up data of 1 035 patients with stage Ⅰ-Ⅲ gastric cancer operated at He'nan Cancer Hospital between May 2015 and Oct 2016 were retrospectively collected. A nomogram was established based on prognostic factors. Harrell's concordance index (C-index), receiver operating characteristic (ROC) curve, calibration curve and decision curve analysis (DCA) were used to verify the performance of the model according to differentiation, calibration and clinical utility.Results:A total of 1 035 patients were enrolled . The median follow-up time was 41.9 months; According to the optimal cutoff value, 170 were with elevated neutrophil-to-lymphocyte ratio (NLR) and 865 with a reduced　ratio; 562 in elevated platelet-to-lymphocyte ratio (PLR) vs. 473 in the reduced group; fibrinogen/albumin ratio (FAR) elevated in 108 group vs. 972 in the reduced group; 180 in the prognostic nutritional index score (PNI) elevated group and 855 in the reduced group. Two hundred and sixty-seven patients were categorized at stage Ⅰ, 334 at stage Ⅱ ,434 at stage Ⅲ. Multivariate regression analysis showed tumor location, vascular tumor thrombus, pTNM stage, FAR, PNI and NLR were independent prognostic factors (all P<0.05). The C-index of the nomogram was 0.723 (95% CI: 0.710 -0.736) and had better clinical utility than the American Joint Committee on Cancer (AJCC) 8th TNM staging system 0.693 (95% CI, 0.681 -0.705). The calibration curve of the nomogram showed that the predicted survival rate was consistent with the actual survival rate in GC patients. Compared to AJCC 8th pTNM staging system, the DCA curve indicate that the nomogram has a higher net income. Conclusion:The nomogram predicting overall survival of patients with stage Ⅰ-Ⅲ gastric cancer is established and verified , which provides better individual prediction than TNM staging system.

【Objective】 To understand the abnormalities of HbA1c in the blood donor population in order to improve blood quality and blood donor safety. 【Methods】 The qualified voluntary blood donors, from April 2021 to March 2022, were recruited from Yueyang Central Blood Station, Loudi Central Blood Station and Chenzhou Central Blood Station. The baseline data and HbA1c screening results of blood donors were collected for cross-sectional analysis. 【Results】 Among 1 397 eligible blood donors, 30.0% (419/1397) was in the prediabetes range (HbA1c 5.7%~6.4%) and 5.3% (74/1397) was in the diabetes range (HbA1c≥6.5%). Logistic regression analysis showed that age (OR=1.073, 95%CI: 1.058~1.088, P<0.05, BMI (OR=1.096, 95%CI: 1.060~1.133, P<0.05), gender (OR=2.392, 95%CI: 1.482~3.303, P<0.05, smoking (OR=2.216, 95%CI: 1.818~3.743, P<0.05), drinking (OR=3.615, 95%CI: 2.240~4.990, P<0.05), and education level (OR=0.077, 95%CI: 0.022~0.278, P<0.05) were the influencing factors of HbA1c in blood donors. 【Conclusion】 Among the blood donors in Hunan, 35.3% had abnormal HbA1c (diabetes and prediabetes). HbA1c screening of blood donors is helpful to improve the health management of blood donors, and may also help to improve the storage quality of red blood cells and reduce the occurrence of adverse reactions to blood transfusion in patients.

Objective:To investigate the effect of smoking on autophagy in alveolar macrophages (AMs) of silicosis patients.Methods:In December 2019, a random sampling method was used to select 42 male patients with silicosis (19 cases of stage II and 23 cases of stage III) who were treated with large volume whole lung lavage from August to December 2017 in the Beidaihe sanatorium. According to the different smoking index of the study subjects (smoking index=smoking cigarette consumptions per day×years of smoking) , we divided them into high (Smoking index>400) , medium (200≤smoking index≤400) , low (smoking index <200) and non-smoking group. The levels of autophagy related proteins LC3, Beclin1, p62 and apoptosis related protein Cleaved Caspase-3 were detected by Western blot. The effects of smoking on autophagy activity of AMs in silicosis were analyzed.Results:The ratio of autophagy related protein LC3 II/LC3 I, the expression of Beclin1, p62, and apoptosis related protein Cleaved Caspase-3 in the high smoking group were significantly higher than that of the middle, low smoking group and the non-smoking group ( P<0.05) . Conclusion:Smoking can aggravate the dysfunction of autophagic degradation in silicosis patients' AMs, which may accelerate the progress of silicosis through increasing apoptosis in AMs.