Traction power systems for electrified railways:evolution,state of the art,and future trends

Traction power systems(TPSs)play a vital role in the operation of electrified railways.The transformation of conventional railway TPSs to novel structures is not only a trend to promote the development of electrified railways toward high-efficiency and resilience but also an inevitable requirement to achieve carbon neutrality target.On the basis of sorting out the power supply structures of conventional AC and DC modes,this paper first reviews the characteristics of the existing TPSs,such as weak power supply flexibility and low-energy efficiency.Furthermore,the power supply structures of various TPSs for future electrified railways are described in detail,which satisfy longer distance,low-carbon,high-efficiency,high-reliability and high-quality power supply requirements.Meanwhile,the application prospects of different traction modes are discussed from both technical and economic aspects.Eventually,this paper introduces the research progress of mixed-system electrified railways and traction power supply technologies without catenary system,speculates on the future development trends and challenges of TPSs and predicts that TPSs will be based on the continuous power supply mode,employing power electronic equipment and intelligent information technology to construct a railway comprehensive energy system with renewable energy.

Pars plana vitrectomy with internal limiting membrane plugging assisted by autologous blood for optic disc pit associated with vitreomacular traction

Dear Editor,We report a case of optic disc pit(ODP)associated with vitreomacular traction which has been successfully treated by a combined technique.We have obtained the written informed consent from the patient,and this case study is in accordance with the tenets of the Declaration of Helsinki.

Research on the longitudinal protection of a through-type cophase traction direct power supply system based on the empirical wavelet transform

This paper proposes a longitudinal protection scheme utilizing empirical wavelet transform(EWT)for a through-type cophase traction direct power supply system,where both sides of a traction network line exhibit a distinctive boundary structure.This approach capitalizes on the boundary’s capacity to attenuate the high-frequency component of fault signals,resulting in a variation in the high-frequency transient energy ratio when faults occur inside or outside the line.During internal line faults,the high-frequency transient energy at the checkpoints located at both ends surpasses that of its neighboring lines.Conversely,for faults external to the line,the energy is lower compared to adjacent lines.EWT is employed to decompose the collected fault current signals,allowing access to the high-frequency transient energy.The longitudinal protection for the traction network line is established based on disparities between both ends of the traction network line and the high-frequency transient energy on either side of the boundary.Moreover,simulation verification through experimental results demonstrates the effectiveness of the proposed protection scheme across various initial fault angles,distances to faults,and fault transition resistances.

Robotic Surgery: An Effective Treatment Option for Epiphrenic Diverticulum Associated with Nutcracker Esophagus

Background: Epiphrenic Diverticulum is frequently associated with esophageal motility disorders, such as nutcrackers esophagus. The diagnosis is usually made using imaging studies such as a Barium esophagogram, and esophageal manometry. Surgical treatment options for epiphrenic diverticulum and EN include diverticulectomy and wide myotomy. Aim: The resection of three epiphrenic diverticula and extensive myotomy were performed by robotic thoracoscopy uneventfully. Case presentation: A 65-year-old female complaining of dysphagia for solid foods, Chest pain and regurgitation. Esophagogastroduodenoscopy (EDG) with difficulty in advancing the endoscope at 25 cm and demonstrating an ED, no hiatal hernia and normal stomach and duodenum. Barium Esophagogram showed multiple diverticula and tortuosity throughout the esophagus. Conclusion: With robotic surgery, surgeons can perform highly precise operations with enhanced 3D vision and control. Through this cutting-edge approach, the treatment of ED associated with EN can be drastically changed, promising better outcomes for patients.

Laparoscopic Orchidopexy after 4 Weeks of Testicular Traction with Preservation of Blood Supply: A New Concept for the Treatment of Intra-Abdominal Cryptorchidism: Original Article

Background: Testicular atrophy is recurrent after orchidopexy for intra-abdominal cryptorchidism due to damage to vessels. Fowlers-Stephens and Shehata methods proposed staged orchidopexy, but are still associated to a rate of atrophy greater than 10%. Purpose: We set out to present a new technique that preserves testicular vessels. Our study is aimed at investigating testicular vitality after surgery. Patients and Method: We reviewed files of boys who underwent orchidopexy for 2 years in our department. Those who have been operated for intra-abdominal cryptorchidism with the new technique and aged between 6 months and 14 years old were included in our study. We excluded boys who have been operated before 6 months and after 14 years old and those who did not respect their follow-up plane. Ultrasound (US) outcomes were used to measure testicular volumes and blood flow at each postoperative visit. The Sample population was divided into group A and group B representing testes that were followed respectively for 12 and 24 months. Results: 22 boys with 25 testes were included in our study;11 testes in group A and 14 testes in group B. In each group, we noted a significant difference of UDT volumes from the third month after surgery with respective P-values 0.05. There was no statistical difference between UDT and contra lateral testes volumes 12 months after surgery in group A and 24 months in group B with respective P-values of 0.07 and 0.72. All volume differential indexes were Conclusion: This method offers a new perspective in performing safe orchidopexy for intra abdominal undescended testes.

Misdiagnosed Meckel's diverticulum with internal hernia mimicking appendicitis:A case report

BACKGROUND Meckel's diverticulum is a common congenital anomaly of the gastrointestinal tract,with a higher incidence rate in children under 7 years old.The condition is characteristically asymptomatic but may become a clinical concern when complications such as intestinal obstruction,bleeding,perforation,or diverticulitis precipitate acute abdominal presentations.CASE SUMMARY This report describes the case of a middle-aged man initially suspected of having acute appendicitis,which rapidly progressed to acute peritonitis with concomitant intestinal obstruction observed during preoperative assessment.Surgical exploration confirmed the diagnosis of Meckel's diverticulum-induced internal hernia,accompanied by intestinal obstruction and necrosis.In addition,the hernial ring base exhibited entrapment resembling a surgical knot.CONCLUSION Meckel's diverticulum is a rare cause of small bowel obstruction in adults,and it should be considered in a differential diagnosis.

A Loss-model-based Efficiency Optimization Control Method for Induction Traction System of High-speed Train under Emergency Self-propelled Mode

Increasing attention has been paid to the efficiency improvement of the induction traction system of high-speed trains due to the high demand for energy saving. In emergency self-propelled mode, however, the dc-link voltage and the traction power of the motor are significantly reduced, resulting in decreased traction efficiency due to the low load and low speed operations. Aiming to tackle this problem, a novel efficiency improved control method is introduced to the emergency mode of high-speed train traction system in this paper. In the proposed method, a total loss model of induction motor considering the behaviors of both iron and copper loss is established. An improved iterative algorithm with decreased computational burden is then introduced, resulting in a fast solving of the optimal flux reference for loss minimization at each control period. In addition, considering the parameter variation problem due to the low load and low speed operations, a parameter estimation method is integrated to improve the controller's robustness. The effectiveness of the proposed method on efficiency improvement at low voltage and low load conditions is demonstrated by simulated and experimental results.

Natural history and surgical treatment of a giant colonic diverticulum:A case report

BACKGROUND While diverticular disease is prevalent in the West,the formation of giant colonic diverticula is rare.To date,approximately 200 cases have been reported,with only a handful treated surgically using a minimally invasive approach.Furthermore,the natural history of giant colonic diverticula is not well documented.CASE SUMMARY This report describes the case of a 66-year-old man who developed a giant colonic diverticulum with primary symptoms including dull and chronic pain in the right lower quadrant at presentation.The patient had undergone several computed tomography scans of the abdomen and pelvis over the previous two years,through which the natural history of this rare entity could be retrospectively observed.The patient was successfully treated with a robot-assisted sigmoid colectomy and had an uneventful recovery with resolution of symptoms during the follow-up.CONCLUSION This rare case demonstrates the natural history of giant colonic diverticulum formation and supports the feasibility of robot-assisted surgery.

Appendicitis combined with Meckel’s diverticulum obstruction, perforation, and inflammation in children: Three case reports

BACKGROUND Meckel’s diverticulum is a common congenital malformation of the small intestine,with the three most common complications being obstruction,per-foration,and inflammation.To date,only a few cases have been reported world-wide.In children,the clinical symptoms are similar to appendicitis.As most of the imaging features are nonspecific,the preoperative diagnosis is not precise.In addition,the clinical characteristics are highly similar to pediatric acute appendicitis,thus special attention is necessary to distinguish Meckel’s diver-ticulum from pediatric appendicitis.Patients with poor disease control should undergo laparoscopic exploration to avoid serious complications,including intestinal necrosis,intestinal perforation and gastrointestinal bleeding.CASE SUMMARY This report presents three cases of appendicitis in children combined with intestinal obstruction,which was caused by fibrous bands(ligaments)arising from the top part of Meckel's diverticulum,diverticular perforation,and diver-ticular inflammation.All three patients,aged 11-12 years,had acute appendicitis as their initial clinical presentation.All were treated by laparoscopic surgery with a favorable outcome.A complete dataset including clinical presentation,dia-gnostic imaging,surgical information,and histopathologic findings was also provided.CONCLUSION Preoperative diagnosis of Meckel’s diverticulum and its complications is challenging because its clinical signs and complications are similar to those of appendicitis in children.Laparoscopy combined with laparotomy is useful for diagnosis and treatment.

Generalized autoencoder-based fault detection method for traction systems with performance degradation

Fault diagnosis of traction systems is important for the safety operation of high-speed trains.Long-term operation of the trains will degrade the performance of systems,which decreases the fault detection accuracy.To solve this problem,this paper proposes a fault detection method developed by a Generalized Autoencoder(GAE)for systems with performance degradation.The advantage of this method is that it can accurately detect faults when the traction system of high-speed trains is affected by performance degradation.Regardless of the probability distribution,it can handle any data,and the GAE has extremely high sensitivity in anomaly detection.Finally,the effectiveness of this method is verified through the Traction Drive Control System(TDCS)platform.At different performance degradation levels,our method’s experimental results are superior to traditional methods.

Effect of endoscopic full-thickness resection assisted by distal serosal turnover with floss traction for gastric submucosal masses

BACKGROUND Complex and high-risk surgical complications pose pressing challenges in the clinical implementation and advancement of endoscopic full-thickness resection(EFTR).Successful perforation repair under endoscopy,thereby avoiding surgical intervention and postoperative complications such as peritonitis,are pivotal for effective EFTR.AIM To investigate the effectiveness and safety of EFTR assisted by distal serosal inversion under floss traction in gastric submucosal tumors.METHODS A retrospective analysis of patients with gastric and duodenal submucosal tumors treated with EFTR assisted by the distal serosa inversion under dental floss traction from January 2023 to January 2024 was conducted.The total operation time,tumor dissection time,wound closure time,intraoperative bleeding volume,length of hospital stay and incidence of complications were analyzed.RESULTS There were 93 patients,aged 55.1±12.1 years.Complete tumor resection was achieved in all cases,resulting in a 100% success rate.The average total operation time was 67.4±27.0 min,with tumor dissection taking 43.6±20.4 min.Wound closure times varied,with gastric body closure time of 24.5±14.1 min and gastric fundus closure time of 16.6±8.7 min,showing a significant difference(P<0.05).Intraoperative blood loss was 2.3±4.0 mL,and average length of hospital stay was 5.7±1.9 d.There was no secondary perforation after suturing in all cases.The incidence of delayed bleeding was 2.2%,and the incidence of abdominal infection was 3.2%.No patient required other surgical intervention during and after the operation.CONCLUSION Distal serosal inversion under dental-floss-assisted EFTR significantly reduced wound closure time and intraoperative blood loss,making it a viable approach for gastric submucosal tumors.

Single-center retrospective study of the diagnostic value of doubleballoon enteroscopy in Meckel’s diverticulum with bleeding

BACKGROUND The study aimed to analyze the characteristic clinical manifestations of patients with intestinal disease Meckel’s diverticulum(MD)complicated by digestive tract hemorrhage.Moreover,we aimed to evaluate the value of double-balloon enteroscopy(DBE)in MD diagnosis and the prognosis after laparoscopic diverticula resection.AIM To evaluate the value of DBE in the diagnosis and the prognosis after laparoscopic diverticula resection for MD with bleeding.METHODS The study retrospectively analyzed relevant data from 84 MD patients treated between January 2015 and March 2022 and recorded their clinical manifestations,auxiliary examination,and follow-up after laparoscopic resection of diverticula.RESULTS(1)Among 84 MD patients complicated with hemorrhage,77 were male,and 7 were female with an average age of 31.31±10.75 years.The incidence was higher in men than in women of different ages;(2)Among the 84 MD patients,65(78.40%)had defecated dark red stools,and 50(58.80%)had no accompanying symptoms during bleeding,indicating that most MD bleeding appeared a dark red stool without accompanying symptoms;(3)The shock index of 71 patients(85.20%)was<1,suggesting that the blood loss of most MD patients was less than 20%–30%,and only a few patients had a blood loss of>30%;(4)The DBE-positive rate was 100%(54/54),99mTcpertechnetate-positive scanning rate was 78%(35/45)compared with capsule endoscopy(36%)and small intestine computed tomography(19%).These results suggest that DBE and 99mTc-pertechnetate scans had significant advantages in diagnosing MD and bleeding,especially DBE was a highly precise examination method in MD diagnosis;(5)A total of 54 MD patients with hemorrhage underwent DBE examination before surgery.DBE endoscopy revealed many mucosal manifestations including normal appearance,inflammatory changes,ulcerative changes,diverticulum inversion,and nodular hyperplasia,with ulcerative changes being the most common(53.70%).This suggests that diverticular mucosal ulcer was the main cause of MD and bleeding;and(6)Laparoscopic dissection of diverticulae was performed in 76 patients,The patients who underwent postoperative follow-up did not experience any further bleeding.Additionally,follow-up examination of the 8 cases who had declined surgery revealed that 3 of them experienced a recurrence of digestive tract bleeding.These findings indicate that laparoscopic diverticula resection in MD patients complicated by bleeding had a favorable prognosis.CONCLUSION Bleeding associated with MD was predominantly observed in male adolescents,particularly at a young age.DBE was a highly precise examination method in MD diagnosis.Laparoscopic diverticula resection effectively prevented MD bleeding and had a good prognosis.

Lasting Attraction

High-level opening up and policies to attract foreign direct investment(FDI)were hot topics during the annual sessions of the National People’s Congress(NPC)and the Chinese People’s Political Consultative Conference(CPPCC)National Committee,China’s key annual political meetings commonly known as Two Sessions.

Device-assisted traction methods in colorectal endoscopic submucosal dissection and options for difficult cases

Endoscopic submucosal dissection(ESD)procedure has a longer procedure time and higher perforation rate than endoscopic mucosal resection owing to technical complications,including a poor field of vision and inadequate tension for the submucosal dissection plane.Various traction devices were developed to secure the visual field and provide adequate tension for the dissection plane.Two randomized controlled trials demonstrated that traction devices reduce colorectal ESD procedure time compared with conventional ESD(C-ESD),but they had limitations,including a single-center fashion.The CONNECT-C trial was the first multicenter randomized controlled trial comparing the C-ESD and traction device-assisted ESD(T-ESD)for colorectal tumors.In the T-ESD,one of the device-assisted traction methods(S-O clip,clip-with-line,and clip pulley)was chosen according to the operator’s discretion.The median ESD procedure time(primary endpoint)was not significantly different between C-ESD and T-ESD.For lesions≥30 mm in diameter or in cases treated by nonexpert operators,the median ESD procedure time tended to be shorter in T-ESD than in C-ESD.Although T-ESD did not reduce ESD procedure time,the CONNECT-C trial results suggest that T-ESD is effective for larger lesions and nonexpert operators in colorectal ESD.Compared with esophageal and gastric ESD,colorectal ESD has some difficulties,including poor endoscope maneuverability,which may be associated with prolonged ESD procedure time.T-ESD may not effectively improve these issues,but a balloon-assisted endoscope and underwater ESD may be promising options and these methods can be combined with T-ESD.

Cooling System Design Optimization of an Enclosed PM Traction Motor for Subway Propulsion Systems

This paper presents the design optimization of a self-circulated ventilation system for an enclosed permanent magnet(PM)traction motor utilized in the propulsion systems for subway trains.In order to analyze accurately the machine's inherent cooling capacity when the train is running,the ambient airflow and the related heat transfer coefficient(HTC)are numerically investigated considering synchronously the bogie installation structure.The machine is preliminary cooled with air ducts set on the motor shell,and the fluidic-thermal field distributions with only the shell air duct cooling are numerically calculated.During simulations,the HTC obtained in the former steps is applied to the external surface of the machine to model the inherent cooling characteristic caused by the train movement.To reduce the temperature rise and thus guarantee the motor's working reliability,an internal self-circulated air cooling system is proposed according to the machine temperature distribution.The air enclosed in the end-caps is driven by the blades mounted on both sides of the rotor core and forms two air circuits to bring the excessive power losses generated in the heating components to cool regions.The fluid flow and temperature rise distributions of the cooling system's structural parameters are further improved by the Taguchi method in order to confirm the efficacy of the internal air cooling system.

Pentalogy of Cantrell with Pentalogy of Fallot and Left Ventricular Diverticulum

Pentalogy of Cantrell is a congenital anomaly characterized by a combination of birth defects involving the sternum,diaphragm,pericardium,abdominal wall,and heart.Pentalogy of Cantrell is a rare anomaly with high mortality.This paper describes the treatment of a 9-month-old girl with pentalogy of Cantrell,pentalogy of Fallot,and left ventricular diverticulum.The patient is alive and well 13 years after surgery.

Visualized analysis of research on myopic traction maculopathy based on CiteSpace

AIM:To analyze the global scientific output concerning myopic traction maculopathy(MTM)and to summarize the research frontiers and hot topics of MTM related researches.METHODS:Data were collected for bibliometric and visualization analyses from Web of Science(WOS)Core Collection.Exported records were analyzed for titles,publication years,research institutions,journal names,authors,keywords,and abstracts using CiteSpace software version 6.1.RESULTS:A total of 839 related studies were analyzed,the publication volume increased annually,with Asia the most active region of MTM research.Optical coherence tomography angiography,optical coherence tomography,macular hole,high myopia,macular buckling were identified as the focus of the current research.Progression,association,classification and shape were identified as the major research frontiers.CONCLUSION:MTM is a major cause of visual loss in pathological myopic eyes.During the preceding 17y,the number of annual publications in MTM research increased gradually.Studies on the progression nature of MTM,genome-wide association study and proper classification of MTM might still be the frontiers of MTM researches.

Damage to the External Genitalia by Traction Following Assault and Battery at the C.H.U Gabriel Touré: About a Case

Trauma to the external genitalia by tearing is rare. We report the case of a 30-year-old patient, admitted to the emergency room for trauma of the external genitalia by traction following a blow and intentional injury. The authors highlight the lesions that can occur during this type of trauma and insist on the systematic search for urethral and cavernous lesions. Conclusion: Trauma to the external genitalia by intentional assault and battery is rare in our context. They occur most often in a young person and are frequently associated with damage to the corpora cavernosa and urethra.

Small bowel diverticulum with enterolith causing intestinal obstruction: A case report

BACKGROUND Small bowel diverticula are rare in clinics,and small intestinal obstruction caused by coprolites is rarer and difficult to diagnose early.The true incidence of these diverticula may be underestimated due to their clinical symptoms not differing from those of small bowel obstruction resulting from other causes.It is common in the elderly,although it can occur at any age.CASE SUMMARY This is a case report of a 78-year-old man with epigastric pain for 5 d.Conservative treatment does not effectively relieve pain,inflammatory indicators are elevated,and computed tomography suggests jejunal intussusception and mild ischemic changes in the intestinal wall.Laparoscopic exploration showed that the left upper abdominal loop was slightly edematous,the jejunum mass at the near Flex ligament was palpable,the size was about 7 cm×8 cm,the local movement was slight,and the diverticulum was seen 10 cm downward,and the local small intestine was dilated and edema.Segmentectomy was performed.After the short parenteral nutrition after surgery,the fluid and enteral nutrition solution were pumped through the jejunostomy tube,and the patient was discharged after the treatment was stable,and the jejunostomy tube was removed in an outpatient clinic one month after the operation.Postoperative pathology:Jejunectomy specimen:(1)Small intestinal diverticulum with chronic inflammation,ulcer with full-thickness activity,and necrosis of the intestinal wall in some areas;(2)also see that the hard object is consistent with stone changes;and(3)the incision margin on both sides shows chronic inflammation of mucosal tissue.CONCLUSION Clinically,the diagnosis of small bowel diverticulum is difficult to distinguish from jejunal intussusception.Combined with the patient’s condition,rule out other possibilities after a timely disease diagnosis.According to the patient’s body tolerance adopt personalized surgical methods to achieve better recovery after surgery.

Two traction methods that can facilitate esophageal endoscopic submucosal dissection

Different traction devices that can provide a visual field and attain appropriate tension at the dissection plane during endoscopic submucosal dissection(ESD)have been developed.Clip-with-line(CWL)is a classic traction device that can offer per-oral traction toward the direction where the line is drawn.A multicenter randomized controlled trial(CONNECT-E trial)comparing the conventional ESD and CWL-assisted ESD(CWL-ESD)for large esophageal tumors was conducted in Japan.This study showed that CWL-ESD was associated with a shorter procedure time(defined as the time from initiating submucosal injection to completing tumor removal)without increasing the risk of adverse events.Multivariate analysis revealed that whole-circumferential lesion and abdominal esophageal lesion were independent risk factors for technical difficulties,which were defined as a procedure time of>120 min,perforation,piecemeal resection,inadvertent incision(any accidental incision caused by the electrosurgical knife within the marked area),or handover to another operator.Therefore,techniques other than CWL should be considered for these lesions.Several studies have shown the usefulness of endoscopic submucosal tunnel dissection(ESTD)for such lesions.A randomized controlled trial conducted at five Chinese institutions showed that compared with the conventional ESD,ESTD had a significantly reduced median procedure time for lesions covering≥1/2 of the esophageal circumference.In addition,a propensity score matching analysis conducted at a single Chinese institution showed that compared with the conventional ESD,ESTD had a shorter mean resection time for lesions at the esophagogastric junction.With the appropriate use of CWL-ESD and ESTD,esophageal ESD can be performed more efficiently and safely.Moreover,the combination of these two methods may be effective.