The gradient field, one of the core magnetic fields in magnetic resonance imaging (MRI) systems, is generated by gradient coils and plays a critical role in spatial encoding and the generation of echo signals. The uniformity or linearity of the gradient field directly impacts the quality and distortion level of MRI images. However, traditional point measurement methods lack accuracy in assessing the linearity of gradient fields, making it difficult to provide effective parameters for image distortion correction. This paper introduced a spherical measurement-based method that involved measuring the magnetic field distribution on a sphere, followed by detailed magnetic field calculations and linearity analysis. This study, applied to assess the nonlinearity of asymmetric head gradient coils, demonstrated more comprehensive and precise results compared to point measurement methods. This advancement not only strengthens the scientific basis for the design of gradient coils but also provides more reliable parameters and methods for the accurate correction of MRI image distortions.
Magnetic Resonance Imaging/instrumentation* ; Humans ; Image Processing, Computer-Assisted/methods* ; Nonlinear Dynamics ; Magnetic Fields ; Algorithms ; Phantoms, Imaging

Objectives:This study aims to investigate the impact of different Low-Density Lipoprotein cholesterol(LDL-C)levels on progression of intermediate coronary stenosis,and the associated risk factors leading to the progression of such lesions. Methods:Data were collected on 219 consecutive patients admitted at the Fuwai Central China Vascular Hospital from January 2020 to February 2021,underwent angiographic examinations and diagnosed with intermediate coronary stenosis,with at least one follow-up angiography after 11 months.Offline quantitative flow ratio(QFR)analysis was performed on these cases.Patients were divided into two groups:LDL-C controlled group(LDL-C<1.8 mmol/L,148 patients with 191 vessels)and LDL-C uncontrolled group(LDL-C≥1.8 mmol/L,71 patients with 98 vessels).Coronary artery QFR and anatomical indicators such as minimal lumen diameter,minimal lumen area,percentage diameter stenosis,percentage area stenosis were compared within and between the groups.Further analysis was performed to identify influencing factors leading to changes in coronary physiological parameters derived from QFR. Results:Within the LDL-C controlled group,there was no significant difference in the QFR values of the vessels compared to baseline(P>0.05),whereas in the LDL-C uncontrolled group(P<0.05),a notable decline in QFR was observed.Patients in the LDL-C controlled group had lower rates of maximum diameter and area stenosis and higher minimum lumen diameter and area(all P<0.05).Through multifactorial Logistic regression analysis,it was found that a body mass index＞28 kg/m2,LDL-C≥1.8 mmol/L,and a history of myocardial infarction were independent risk factors leading to the decline in QFR(all P<0.05). Conclusions:It was found that patients in the LDL-C controlled group had higher coronary artery QFR,minimum lumen diameter and area,lower rates of maximum diameter and area stenosis.

Objective:To evaluate the safety and efficacy of transtobturator urethral sling operation in the treatment of male stress urinary incontinence.Methods:A retrospective analysis was conducted on the clinical data of 13 male patients with stress urinary incontinence who underwent transvaginal sling procedure at Peking University People's Hospital from June 2011 to July 2024. The patients' average age was (71.6±5.4) years. Among them, 9 patients had undergone radical prostatectomy, and 4 had undergone transurethral resection of the prostate (TURP). Of the 13 patients, 7 had moderate urinary incontinence, and 6 had severe urinary incontinence. The median daily number of urine pads used by the 13 patients before surgery was 5 (3, 8), and the median score of the Incontinence Quality of Life Questionnaire (I-QOL) was 16 (12, 28). The median score of the Male Stress Urinary Incontinence Grading Scale (MSIGS) was 2 (2, 3). All the 13 patients underwent transvaginal sling procedure. The patients were placed in the lithotomy position, and the urethral bulb was dissected anatomically beneath the scrotum. The sling was guided by a needle and pulled out through the obturator foramen, and placed over the urethral bulb. The sling was tightened and the tension adjusted to fully suspend the urethra. A urinary catheter was left in place for 1-7 days after surgery. The patients' postoperative daily use of urine pads, scores of the I-QOL and MSIGS, and postoperative complications were followed up.Results:Postoperative follow-up ranged from 2 to 139 months, with a median follow-up time of 12 months. Of the 13 patients, 2 were cured, 9 had improved and 2 had no significant improvement. The number of diapers used per day by patients postoperatively was 1 (1, 4) pieces, the I-QOL score was 75 (46, 82), and the MSIGS score was 1 (0, 2), which were all significantly improved compared to preoperative values ( P<0.01). Among the 6 severe stress urinary incontinence patients who were followed up, the number of diapers used per day was significantly reduced compared to preoperative values[ 2(1, 5) vs. 8(7, 8) pieces], and the I-QOL score was significantly improved [ 60(35, 70) vs. 12(10, 16) ], while the MSIGS score was significantly lower [ 2(1, 3) vs. 3(2, 4) ]. Among the 7 moderate stress urinary incontinence patients, the number of diapers used per day was significantly reduced compared to preoperative values [1 (0, 1) vs. 4 (4, 5) pieces], and the I-QOL score was significantly improved [ 80(75, 82) vs. 21(18, 30) ], while the MSIGS score was significantly lower [ 0 (0, 1) vs. 2 (2, 3) ]. The symptoms of 1 patient were not significantly improved after the surgery, and were improved after Virtue sling suspension 3 years later. Conclusions:The use of transtobturator urethral sling operation for the treatment of moderate to severe male stress urinary incontinence has shown clear efficacy, with a low incidence of postoperative complications.

Radiotherapy (RT) is one of the most common treatments for cancer. However, intracellular glutathione (GSH) plays a key role in protecting cancer from radiation damage. Herein, we have developed a platelet membrane biomimetic nanomedicine (PMD) that induces double GSH consumption to enhance tumor radioimmunotherapy. This biomimetic nanomedicine consists of an external platelet membrane and internal organic mesoporous silica nanoparticles (MON) loaded with 2-deoxy-D-glucose (2-DG). Thanks to the tumor-targeting ability of the platelet membranes, PMD can target and aggregate to the tumor site, which is internalized by tumor cells. Within tumor cells overexpressing GSH, MON reacts with GSH to degrade and release 2-DG. This step initially depletes the intracellular GSH content. The subsequent release of 2-DG inhibits glycolysis and adenosine triphosphate (ATP) production, ultimately leading to secondary GSH consumption. This nanodrug combines dual GSH depletion, starvation therapy, and RT to promote immunogenic cell death and stimulate the systemic immune response. In the bilateral tumor model in vivo, distal tumor growth was also well suppressed. The proportion of mature dendritic cells (DC) and CD8⁺ T cells in the mice was increased. This indicates that PMD can promote anti-tumor radioimmunotherapy and has good prospects for clinical application.

【Objective】 To explore the clinical features and treatment outcomes of female urethral carcinoma so as to improve the awareness and prognosis of this rare malignant disease. 【Methods】 Clinical data of 8 cases of female urethral carcinoma treated during Jan. 2012 to Dec.2022 at the Department of Urology of Peking University People’s Hospital were retrospectively analyzed. The patients underwent urodynamic tests, cystourethroscopy and pathological biopsy to confirm the diagnosis. Traditional radical surgery was performed in 5 cases, and radical surgery for lower urethral cancer with bladder preservation was performed in 3 cases. 【Results】 The patients aged 36 to 68 years, with a mean of 53.75 years. Urinary obstruction, lower urinary tract symptoms and urethral masses were common manifestations. Urodynamic tests indicated bladder outlet obstruction. After surgical treatment, radical surgery for lower urethral cancer with bladder preservation showed advantages over traditional radical surgery in terms of intraoperative bleeding, operation time and postoperative hospital stay. 【Conclusion】 Female primary urethral carcinoma is rare but invasive. Early diagnosis and radical surgery are crucial for improving the prognosis. Radical surgery for lower urethral cancer with bladder preservation has better treatment outcomes and postoperative quality of life compared to traditional radical surgery. For such patients, symptoms should be closely monitored and timely diagnosis and treatment should be performed.

Objective:To explore the characteristics of vocal cord polyps and to study the application value of high-frequency ultrasound in the diagnosis of vocal cord polyps.Methods:A total of 169 patients diagnosed with vocal cord polyps ( 176 polyps in total ) by pathology in the Second Affiliated Hospital of Xi′an Jiaotong University from December 2016 to September 2021 were collected, the ultrasonic image characteristics of vocal cord polyps were summarized, and the characteristics of thyroid cartilage calcification at glottic level and the influence of the calcification range of thyroid cartilage at glottic level on the display of vocal cord polyps were observed.Results:The sonogram images of all vocal cord polyps showed the localized uniform low echo between the upper cortex and the ligament layer, the morphology could be circular and flat, and all polyps could be divided into high tension type and low tension type, no blood flow signal was found in 96.8% of the polyps. Round polyps were more easier to be detected by ultrasound than flat polyps, but there was no significant difference( P>0.05). The incidence of thyroid cartilage calcification at glottis level was higher in men than in women, and the difference was statistically significant( P<0.05). The range of thyroid cartilage calcification at the glottic level affects the display rate of vocal cord polyps.With the increase of calcification range, the display rate of vocal cord polyps gradually decreased. There was significant difference in the display rate of vocal cord polyps between non calcification group and moderate calcification group, non calcification group and severe calcification group(all P<0.05). Conclusions:Vocal cord polyps have typical sonographic appearance. High-frequency ultrasound can identify the morphology, location and size of vocal cord polyps. Especially for patients with no or mild calcification of thyroid cartilage at glottic level, ultrasound can meet the requirements of accurate diagnosis. It is expected to become an effective supplement to laryngoscopy, and apply for to the preliminary screening of vocal cord polyps and postoperative review.

Objective:To evaluate the long-term efficacy of AdVance sling bulbar urethral suspension and artificial urethral sphincter (AUS) implantation in the treatment of moderate to severe male stress urinary incontinence.Methods:The clinical data of 12 male patients with urinary incontinence who underwent surgical treatment in Peking University People's Hospital from June 2011 to June 2017 were retrospectively analyzed. The median age was 75(64-80) years. There were 9 cases after radical prostatectomy and 3 cases after transurethral prostatectomy. Patients had a median history of urinary incontinence of 3(1-9) years, and needed an average of 8(5-10) pads per day. Among them, 5 patients had moderate urinary incontinence and 7 patients had severe urinary incontinence. All patients underwent urinary incontinence surgery for the first time. Among the 12 patients, 6 received AdVance sling ball urethral suspension (AdVance group), and 6 received AUS implantation (AUS group). The median age of the AdVance group was 72 (64-73) years. The median number of pads used daily was 6 (5-8) tablets. Urinary incontinence Quality of Life questionnaire (I-QOL) score was (15.0±5.4). Five patients had moderate urinary incontinence and one patient had severe urinary incontinence. In the AUS group, the median age was 78(76-80) years old, the median daily pad use was 8(6-10) tablets, and the I-QOL score was (16.7±5.1), all of which were severe urinary incontinence. The daily pad usage, I-QOL and postoperative complications were recorded at 1 and 5 years after operation.Results:All patients completed the operation successfully. The postoperative follow-up was 5-7 years (mean 5.5 years). In AdVance group, 1 patient with severe urinary incontinence had no significant improvement in postoperative symptoms at 1 year after operation. The other 5 patients showed significant improvement in urinary incontinence symptoms. In the AdVance group, the median number of pads used per day was 2.5 (1-10), and the I-QOL score was (75.0±28.1), which were all significantly improved compared with that before operation ( P<0.05). The median number of pads used per day in the AdVance group 5 years after operation was 2.5(1-10), and the I-QOL score was (78.3±29.3), which were significantly improved compared with those before operation (all P<0.01). In the AUS group, no pad was needed at 1 year after operation, which was significantly improved compared with that before operation ( P<0.01). Urethral erosion occurred in 2 cases 3 years after operation, and the AUS was removed. Urinary incontinence recurred and returned to the preoperative state without reoperation. The other 4 cases did not need to use the pad 5 years after operation. In AdVance group, 3 patients had perineal pain within 3 months after operation, which was related to activity and relieved spontaneously. No wound infection, urethral erosion and other complications occurred. Urethral erosion occurred in 3 cases in AUS group. Conclusions:AdVance sling ball urethral suspension is effective for patients with moderate stress urinary incontinence and has fewer complications. AUS implantation is effective for patients with severe male stress urinary incontinence. However, the long-term complications of this operation may affect the postoperative efficacy.

The avian influenza A (H7N9) virus is a zoonotic virus that is closely associated with live poultry markets. It has caused infections in humans in China since 2013. Five waves of the H7N9 influenza epidemic occurred in China between March 2013 and September 2017. H7N9 with low-pathogenicity dominated in the first four waves, whereas highly pathogenic H7N9 influenza emerged in poultry and spread to humans during the fifth wave, causing wide concern. Specialists and officials from China and other countries responded quickly, controlled the epidemic well thus far, and characterized the virus by using new technologies and surveillance tools that were made possible by their preparedness efforts. Here, we review the characteristics of the H7N9 viruses that were identified while controlling the spread of the disease. It was summarized and discussed from the perspectives of molecular epidemiology, clinical features, virulence and pathogenesis, receptor binding, T-cell responses, monoclonal antibody development, vaccine development, and disease burden. These data provide tools for minimizing the future threat of H7N9 and other emerging and re-emerging viruses, such as SARS-CoV-2.
Animals ; COVID-19 ; China/epidemiology* ; Humans ; Influenza A Virus, H7N9 Subtype ; Influenza in Birds/epidemiology* ; Influenza, Human/prevention & control* ; Poultry ; SARS-CoV-2

More and more studies have found that red blood cell distribution width (RDW) can be used for acute pancreatitis (AP) classification, dynamic monitoring and evaluation of disease severity, mortality, prognosis and complication. Some inflammatory markers, such as procalcitonin (PCT), C-reactive protein (CRP), neutrophil-to-lymphocyte ratio (NLR) and pancreatitis scoring system are also associated with severity of AP, and can further improve the evaluation of AP severity when combined with RDW. This article reviewed the RDW and classification of AP, the dynamic changes of RDW and AP, RDW combined with inflammatory indices for prediction of severity of AP, and RDW combined with pancreatitis scoring system for prediction of severity of AP, so as to improve the understanding of predictive value of RDW in assessing the severity of AP.

Objective:To summarize the patient profiles and therapeutic efficacies of ABO-incompatible living-related kidney transplantations at 19 domestic transplant centers and provide rationales for clinical application of ABOi-KT.Methods:Clinical cases of ABO-incompatible/compatible kidney transplantation (ABOi-KT/ABOc-KT) from December 2006 to December 2009 were collected. Then, statistical analyses were conducted from the aspects of tissue matching, perioperative managements, complications and survival rates of renal allograft or recipients.Results:Clinical data of 342 ABOi-KT and 779 ABOc-KT indicated that (1) no inter-group differences existed in age, body mass index (BMI), donor-recipient relationship or waiting time of pre-operative dialysis; (2) ABO blood type: blood type O recipients had the longest waiting list and transplantations from blood type A to blood type O accounted for the largest proportion; (3) HLA matching: no statistical significance existed in mismatch rate or positive rate of PRA I/II between two types of surgery; (4) CD20 should be properly used on the basis of different phrases; (5) hemorrhage was a common complication during an early postoperative period and microthrombosis appeared later; (6) no difference existed in postoperative incidence of complications or survival rate of renal allograft and recipients at 1/3/5/10 years between ABOi-KT and ABOc-KT. The acute rejection rate and serum creatinine levels of ABOi-KT recipients were comparable to those of ABOc-KT recipients within 1 year.Conclusions:ABOi-KT is both safe and effective so that it may be applied at all transplant centers as needed.