The penetration of new energy sources such as wind power is increasing,which consequently increases the occurrence rate of subsynchronous oscillation events.However,existing subsynchronous oscillation source-identific...The penetration of new energy sources such as wind power is increasing,which consequently increases the occurrence rate of subsynchronous oscillation events.However,existing subsynchronous oscillation source-identification methods primarily analyze fixed-mode oscillations and rarely consider time-varying features,such as frequency drift,caused by the random volatility of wind farms when oscillations occur.This paper proposes a subsynchronous oscillation sourcelocalization method that involves an enhanced short-time Fourier transform and a convolutional neural network(CNN).First,an enhanced STFT is performed to secure high-resolution time-frequency distribution(TFD)images from the measured data of the generation unit ports.Next,these TFD images are amalgamated to form a subsynchronous oscillation feature map that serves as input to the CNN to train the localization model.Ultimately,the trained CNN model realizes the online localization of subsynchronous oscillation sources.The effectiveness and accuracy of the proposed method are validated via multimachine system models simulating forced and natural oscillation events using the Power Systems Computer Aided Design platform.Test results show that the proposed method can localize subsynchronous oscillation sources online while considering unpredictable fluctuations in wind farms,thus providing a foundation for oscillation suppression in practical engineering scenarios.展开更多
Permanent magnet synchronous motor(PMSM)speed control systems with conventional linear active disturbance rejection control(CLADRC)strategy encounter issues regarding the coupling between dynamic response and disturba...Permanent magnet synchronous motor(PMSM)speed control systems with conventional linear active disturbance rejection control(CLADRC)strategy encounter issues regarding the coupling between dynamic response and disturbance suppression and have poor performance in suppressing complex nonlinear disturbances.In order to address these issues,this paper proposes an improved two-degree-of-freedom LADRC(TDOF-LADRC)strategy,which can enhance the disturbance rejection performance of the system while decoupling entirely the system's dynamic and anti-disturbance performance to boost the system robustness and simplify controller parameter tuning.PMSM models that consider total disturbances are developed to design the TDOF-LADRC speed controller accurately.Moreover,to evaluate the control performance of the TDOF-LADRC strategy,its stability is proven,and the influence of each controller parameter on the system control performance is analyzed.Based on it,a comparison is made between the disturbance observation ability and anti-disturbance performance of TDOF-LADRC and CLADRC to prove the superiority of TDOF-LADRC in rejecting disturbances.Finally,experiments are performed on a 750 W PMSM experimental platform,and the results demonstrate that the proposed TDOF-LADRC exhibits the properties of two degrees of freedom and improves the disturbance rejection performance of the PMSM system.展开更多
In this editorial we comment on the manuscript,describing management and surveillance strategies in synchronous and metachronous,gastric and colon cancers.Synchronous or metachronous primary malignancies at different ...In this editorial we comment on the manuscript,describing management and surveillance strategies in synchronous and metachronous,gastric and colon cancers.Synchronous or metachronous primary malignancies at different sites of the gastrointestinal tract pose a unique diagnostic and therapeutic challenge.Multidisciplinary services and strategies are required for the management of multiple site primary malignancies,to provide the best oncological outcomes.Although this study highlights the dual cancers in 76 sporadic cases,the authors excluded 55 patients due to combination of factors which includes;incomplete clinical data,genetic syndrome,gastric stump cancers.In addition,the authors did not elaborate if any patients presented with signet ring cell morphology,E-cadherin mutations or presence of inflammatory bowel disease.Genetic and mutational errors and epithelial field defects from chronic inflammatory diseases of the gastrointestinal tract are important when considering synchronous gastric and colonic cancers.We will briefly discuss these in this editorial.展开更多
In the DC microgrid,the lack of inertia and damping in power electronic converters results in poor stability of DC bus voltage and low inertia of the DC microgrid during fluctuations in load and photovoltaic power.To ...In the DC microgrid,the lack of inertia and damping in power electronic converters results in poor stability of DC bus voltage and low inertia of the DC microgrid during fluctuations in load and photovoltaic power.To address this issue,the application of a virtual synchronous generator(VSG)in grid-connected inverters control is referenced and proposes a control strategy called the analogous virtual synchronous generator(AVSG)control strategy for the interface DC/DC converter of the battery in the microgrid.Besides,a flexible parameter adaptive control method is introduced to further enhance the inertial behavior of the AVSG control.Firstly,a theoretical analysis is conducted on the various components of the DC microgrid,the structure of analogous virtual synchronous generator,and the control structure’s main parameters related to the DC microgrid’s inertial behavior.Secondly,the voltage change rate tracking coefficient is introduced to adjust the change of the virtual capacitance and damping coefficient flexibility,which further strengthens the inertia trend of the DC microgrid.Additionally,a small-signal modeling approach is used to analyze the approximate range of the AVSG’s main parameters ensuring system stability.Finally,conduct a simulation analysis by building the model of the DC microgrid system with photovoltaic(PV)and battery energy storage(BES)in MATLAB/Simulink.Simulation results from different scenarios have verified that the AVSG control introduces fixed inertia and damping into the droop control of the battery,resulting in a certain level of inertia enhancement.Furthermore,the additional adaptive control strategy built upon the AVSG control provides better and flexible inertial support for the DC microgrid,further enhances the stability of the DC bus voltage,and has a more positive impact on the battery performance.展开更多
BACKGROUND Studies evaluating the characteristics of dual primary gastric and colorectal cancer(CRC)(DPGCC)are limited.AIM To analyze the clinicopathologic characteristics and prognosis of synchronous and metachronous...BACKGROUND Studies evaluating the characteristics of dual primary gastric and colorectal cancer(CRC)(DPGCC)are limited.AIM To analyze the clinicopathologic characteristics and prognosis of synchronous and metachronous cancers in patients with DPGCC.METHODS From October 2010 to August 2021,patients with DPGCC were retrospectively reviewed.The patients with DPGCC were divided into two groups(synchronous and metachronous).We compared the overall survival(OS)between the groups using Kaplan-Meier survival methods.Univariate and multivariate analyses were performed using Cox’s proportional hazards model to identify the independent prognostic factors for OS.RESULTS Of the 76 patients with DPGCC,46 and 30 had synchronous and metachronous cancers,respectively.The proportion of unresectable CRC in patients with synchronous cancers was higher than that in patients with metachronous cancers(28.3%vs 3.3%,P=0.015).The majority of the second primary cancers had occurred within 5 years.Kaplan-Meier survival analysis showed that the patients with metachronous cancers had a better prognosis than patients with synchronous cancers(P=0.010).The patients who had undergone gastrectomy(P<0.001)or CRC resection(P<0.001)had a better prognosis than those who had not.In the multivariate analysis,synchronous cancer[hazard ratio(HR)=6.8,95%confidence interval(95%CI):2.0-22.7,(P=0.002)]and stage III-IV gastric cancer(GC)[HR=10.0,95%CI:3.4-29.5,(P<0.001)]were risk prognostic factor for OS,while patients who underwent gastrectomy was a protective prognostic factor for OS[HR=0.2,95%CI:0.1-0.6,P=0.002].CONCLUSION Regular surveillance for metachronous cancer is necessary during postoperative follow-up.Surgical resection is the mainstay of therapy to improve the prognosis of DPGCC.The prognosis appears to be influenced by the stage of GC rather than the stage of CRC.Patients with synchronous cancer have a worse prognosis,and its treatment strategy is worth further exploration.展开更多
The magnetic field generated in the air gap of the cage asynchronous machine and the harmonics of the magnetomotive forces creating that magnetic field,as well as the synchronous parasitic torques,radial magnetic forc...The magnetic field generated in the air gap of the cage asynchronous machine and the harmonics of the magnetomotive forces creating that magnetic field,as well as the synchronous parasitic torques,radial magnetic forces have been discussed in great detail in the literature,but always separately,for a long time.However,systematization of the phenomenon still awaits.Therefore,it is worth summarizing the completeness of the phenomena in a single study–with a new approach at the same time-in order to reveal the relationships between them.The role of rotor slot number is emphasized much more than before.New formulas derived for both synchronous torques and radial magnetic forces are used for further investigation.It will be shown that both phenomena in subject must be treated together.Formulas will be provided to take into account attenuation.Design guide will be provided to avoid dangerous rotor slot numbers.It will be shown that the generation of synchronous torques and radial magnetic forces do not depend–in this new approach-on the slot combination,but on the rotor slot number itself.展开更多
In this paper, an adaptive gain tuning rule is designed for the nonlinear sliding mode speed control(NSMSC) in order to enhance the dynamic performance and the robustness of the permanent magnet assisted synchronous r...In this paper, an adaptive gain tuning rule is designed for the nonlinear sliding mode speed control(NSMSC) in order to enhance the dynamic performance and the robustness of the permanent magnet assisted synchronous reluctance motor(PMa-Syn RM) with considering the parameter uncertainties. A nonlinear sliding surface whose parameters are altering with time is designed at first. The proposed NSMSC can minimize the settling time without any overshoot via utilizing a low damping ratio at starting along with a high damping ratio as the output approaches the target set-point. In addition, it eliminates the problem of the singularity with the upper bound of an uncertain term that is hard to be measured practically as well as ensures a rapid convergence in finite time, through employing a simple adaptation law. Moreover, for enhancing the system efficiency throughout the constant torque region, the control system utilizes the maximum torque per ampere technique. The nonlinear sliding surface stability is assured via employing Lyapunov stability theory. Furthermore, a simple sliding mode estimator is employed for estimating the system uncertainties. The stability analysis and the experimental results indicate the effectiveness along with feasibility of the proposed speed estimation and the NSMSC approach for a 1.1-k W PMa-Syn RM under different speed references, electrical and mechanical parameters disparities, and load disturbance conditions.展开更多
In order to enhance the transient performance of aircraft high voltage DC(HVDC)generation system with wound rotor synchronous machine(WRSM)under a wide speed range,the nonlinear PI multi-loop control strategy is propo...In order to enhance the transient performance of aircraft high voltage DC(HVDC)generation system with wound rotor synchronous machine(WRSM)under a wide speed range,the nonlinear PI multi-loop control strategy is proposed in this paper.Traditional voltage control method is hard to achieve the dynamic performance requirements of the HVDC generation system under a wide speed range,so the nonlinear PI parameter adjustment,load current feedback and speed feedback are added to the voltage and excitation current double loop control.The transfer function of the HVDC generation system is derived,and the relationship between speed,load current and PI parameters is obtained.The PI parameters corresponding to the load at certain speed are used to shorten the adjusting time when the load suddenly changes.The dynamic responses in transient processes are analyzed by experiment.The results illustrate that the WRSM HVDC generator system with this method has better dynamic performance.展开更多
Dual three-phase Permanent Magnet Synchronous Motor(DTP-PMSM)is a nonlinear,strongly coupled,high-order multivariable system.In today’s application scenarios,it is difficult for traditional PI controllers to meet the...Dual three-phase Permanent Magnet Synchronous Motor(DTP-PMSM)is a nonlinear,strongly coupled,high-order multivariable system.In today’s application scenarios,it is difficult for traditional PI controllers to meet the requirements of fast response,high accuracy and good robustness.In order to improve the performance of DTP-PMSM speed regulation system,a control strategy of PI controller based on genetic algorithm is proposed.Firstly,the basic mathematical model of DTP-PMSM is established,and the PI parameters of DTP-PMSM speed regulation system are optimized by genetic algorithm,and the modeling and simulation experiments of DTP-PMSM control system are carried out by MATLAB/SIMULINK.The simulation results show that,compared with the traditional PI control,the proposed algorithm significantly improves the performance of the control system,and the speed output overshoot of the GA-PI speed control system is smaller.The anti-interference ability is stronger,and the torque and double three-phase current output fluctuations are smaller.展开更多
In areas with seasonal freezing,when the tunnel lining concrete is saturated with water infiltrating the interior,the lining and the surrounding rocks will simultaneously freeze.However,the current calculation of the ...In areas with seasonal freezing,when the tunnel lining concrete is saturated with water infiltrating the interior,the lining and the surrounding rocks will simultaneously freeze.However,the current calculation of the frost heaving force fails to consider the synchronous damage to the lining and surrounding rocks under freeze-thaw cycles.Therefore,as per the elastic calculation model of the frost heaving force and model of steady-state heat transfer of circular tunnels,this study introduces the frost heaving rate of lining and surrounding rocks.First,the analytical solution of frost heaving force is obtained for simultaneous frost heaving of lining and surrounding rocks under any steady-state temperature field.Then,based on the fracture theory and meso-damage mechanics,the damage variables of lining and surrounding rocks under freeze-thaw cycles are extracted,representing their elastic modulus and porosity.Finally,the formula of frost heaving force for synchronous damage to the lining and surrounding rocks at any steady-state temperature field is obtained.The calculation results demonstrate that the lower the temperature inside the lining,the greater the frost heaving force.With the increasing number of freeze-thaw cycles,frost heaving force tends to gradually increase initially,reaching a peak value at 85 freeze-thaw cycles,decreasing to 80%of the peak value at 140 cycles before reaching a constant value.The lining participates in frost heaving,increasing the frost heaving force.The initial increase rate of frost heaving force is 15.7%.Changing the fitting coefficients s1 and s2 of the lining and surrounding rocks can effectively control the magnitude of the frost heaving force in the tunnels.展开更多
An improved rheo-optic in situ synchronous measurement system was employed to investigate the gelation behaviour and mechanism of waxy crude oil emulsions. By combining transmitted natural light and reflected polarize...An improved rheo-optic in situ synchronous measurement system was employed to investigate the gelation behaviour and mechanism of waxy crude oil emulsions. By combining transmitted natural light and reflected polarized light microscopy, a multiangle composite light source was built to achieve the simultaneous observation of wax crystals and emulsified water droplets, as well as their dynamic aggregation process. Main outcomes on the microscopic mechanism were obtained by developed microscopic image processing method. It was found that the microstructure of W/O waxy crude oil emulsion has the evolution of “individual structure--homogeneous aggregate structure--heterogeneous coaggregate structure--floc structure” during the static cooling, which results in the four stages during gelation process. Different from previous studies, the aggregation of emulsified water droplets was found to be more significant and contributes to the formation and development of the wax crystals-emulsified water droplets coaggregate, which plays a decisive role in the further evolution of the gelled microstructure. Time series microscopic images show the dynamic aggregation of emulsified water droplets and wax crystals. Two different aggregation behaviours between wax crystals and water droplets were observed. That wax crystals can not only embed in gaps between adjacent water droplets and enhance the structure, but also surround the outside of the water droplets and continue to grow resulting in the interconnection of different coaggregates to form a larger floc structure. In addition, correlation between viscoelasticity and microstructure evolution of waxy crude oil emulsions of different water contents was discussed. With increasing water contents, the microstructure is changed from wax crystal flocculation structure as the main skeleton and the emulsified water droplets embedded in it, into the aggregation of emulsified water droplets occupying the main position. When the number of wax crystals and water droplets reaches a certain ratio, did wax crystals form coaggregates with emulsified water droplets, and the remaining wax crystals formed an overall flocculation structure, the viscoelasticity of the waxy crude oil emulsion is the highest.展开更多
Periodic components are of great significance for fault diagnosis and health monitoring of rotating machinery.Time synchronous averaging is an effective and convenient technique for extracting those components.However...Periodic components are of great significance for fault diagnosis and health monitoring of rotating machinery.Time synchronous averaging is an effective and convenient technique for extracting those components.However,the performance of time synchronous averaging is seriously limited when the separate segments are poorly synchronized.This paper proposes a new averaging method capable of extracting periodic components without external reference and an accurate period to solve this problem.With this approach,phase detection and compensation eliminate all segments'phase differences,which enables the segments to be well synchronized.The effectiveness of the proposed method is validated by numerical and experimental signals.展开更多
BACKGROUND Multiple primary malignant neoplasms(MPMNs)are rare,while synchronous MPMNs(SMPMNs)are even less common.Owing to the progression of medical technology and the extension of life expectancy,its incidence is g...BACKGROUND Multiple primary malignant neoplasms(MPMNs)are rare,while synchronous MPMNs(SMPMNs)are even less common.Owing to the progression of medical technology and the extension of life expectancy,its incidence is gradually increasing.CASE SUMMARY Although reports of breast and thyroid dual cancers are common,cases of an additional diagnosis of kidney primary cancer within the same individual are rare.CONCLUSION We present a case of simultaneous MPMN of three endocrine organs,reviewing the relevant literature to enhance our understanding of SMPMNs while emphasizing the increasingly important need for accurate diagnosis and multidisciplinary management whenever this challenging situation arises.展开更多
BACKGROUND Synchronous colorectal carcinomas(SCRC)are two or more primary colorectal carcinomas identified simultaneously or within 6 mo of the initial presentation in a single patient.Their incidence is low and the n...BACKGROUND Synchronous colorectal carcinomas(SCRC)are two or more primary colorectal carcinomas identified simultaneously or within 6 mo of the initial presentation in a single patient.Their incidence is low and the number of pathological types of SCRC is usually no more than two.It is very unusual that the pathological findings of a patient with SCRC show more than two different pathological subtypes.Here,we report a rare case of SCRC with three pathological subtypes.CASE SUMMARY A 75-year-old woman who had no previous medical history or family history was admitted to the hospital because of intermittent hematochezia for more than a month.Colonoscopy displayed an irregularly shaped neoplasm of the rectum,a tumor-like lesion causing intestinal stenosis in the descending colon,and a polypoidal neoplasm in the ileocecum.Subsequently,she underwent total colectomy,abdominoperineal resection for rectal cancer,and ileostomy.After operation,the pathological report showed three pathological subtypes including well-differentiated adenocarcinoma of the ascending colon,moderately differen-tiated adenocarcinoma of the descending colon,and mucinous adenocarcinoma of the rectum.She is now recovering well and continues to be closely monitored during follow-up.CONCLUSION Preoperative colonoscopy examination,imaging examination,and extensive intraoperative exploration play important roles in reducing the number of missed lesions.展开更多
BACKGROUND To evaluate the clinicopathological features and prognosis of gastric cancer(GC)occurring synchronously with gastrointestinal stromal tumor(GIST).CASE SUMMARY We report 19 patients with concurrent GC and GI...BACKGROUND To evaluate the clinicopathological features and prognosis of gastric cancer(GC)occurring synchronously with gastrointestinal stromal tumor(GIST).CASE SUMMARY We report 19 patients with concurrent GC and GIST(17 male and 2 female,median age 62 years).GC was most often located in the lower third of the stomach.GIST was diagnosed preoperatively in four patients.GIST was most often located in the gastric body(n=8,42%).The most common growth pattern in GIST was extraluminal(n=12,63%).The positive expression rates of CD117 and CD34 in GIST were 100% and 95%,respectively.Most patients with GIST(n=17,89%)were very low or low risk.There was no recurrence of GIST during follow-up.The 3-year cumulative survival rate was 73.9%,and the 5-year cumulative survival rate was 59.2%.The combined analysis of this study and literature reports(47 reports,157 patients)found that GC and GIST were usually located in the lower third(42%)and middle third(51%)of the stomach.GC was usually early(stage I:42%),poorly differentiated(42%)intestinal-type adenocarcinoma(51%).GISTs were primarily small in diameter(median:1.2 cm)and very low or low risk(89%).CONCLUSION Synchronous GC and GIST may not be rare.They have specific clinicopathological characteristics,and may have mutual inhibition in pathogenesis and progression.展开更多
High rates of extrapancreatic malignancies,in particular colorectal cancer(CRC),have been detected in patients with intraductal papillary mucinous neoplasm(IPMN).So far,there is no distinct explanation in the literatu...High rates of extrapancreatic malignancies,in particular colorectal cancer(CRC),have been detected in patients with intraductal papillary mucinous neoplasm(IPMN).So far,there is no distinct explanation in the literature for the development of secondary or synchronous malignancies in patients with IPMN.In the past few years,some data related to common genetic alterations in IPMN and other affiliated cancers have been published.This review elucidated the association between IPMN and CRC,shedding light on the most relevant genetic alterations that may explain the possible relationship between these entities.In keeping with our findings,we suggested that once the diagnosis of IPMN is made,special consideration of CRC should be undertaken.Presently,there are no specific guidelines regarding colorectal screening programs for patients with IPMN.We recommend that patients with IPMNs are at high-risk for CRC,and a more rigorous colorectal surveillance program should be implemented.展开更多
BACKGROUND A large percentage of patients with ectopic pancreas are asymptomatic.When present,the symptoms are typically non-specific.These lesions are predominantly located in the stomach and benign in nature.Synchro...BACKGROUND A large percentage of patients with ectopic pancreas are asymptomatic.When present,the symptoms are typically non-specific.These lesions are predominantly located in the stomach and benign in nature.Synchronous multiple early gastric cancer(SMEGC)(two or more simultaneous malignant lesions with early gastric cancer)is relatively rare and particularly easy to overlook during endoscopic examination.The prognosis of SMEGC is generally poor.We report a rare case of ectopic pancreas with concomitant SMEGC.CASE SUMMARY A 74-year-old woman presented with paroxysmal upper abdominal pain.On initial investigations,she tested positive for Helicobacter pylori(H.pylori).She underwent esophagogastroduodenoscopy which revealed a 1.5 cm×2 cm major lesion at the greater curvature and a 1 cm minor lesion at the lesser curvature of the stomach.On endoscopic ultrasound,the major lesion showed hypoechoic changes,uneven internal echoes and unclear boundaries between some areas and the muscularis propria.Endoscopic submucosal dissection was performed to excise the minor lesion.A laparoscopic resection was chosen for the major lesion.On histopathological examination,the major lesion contained high grade intraepithelial neoplasia with a small focus of cancer.A separate underlying ectopic pancreas was found under this lesion.The minor lesion contained high grade intraepithelial neoplasia.In this case,the patient was diagnosed with SMEGC with concomitant ectopic pancreas in the stomach.CONCLUSION Patients with atrophy,H.pylori,and other risk factors should be carefully investigated to avoid missing other lesions including SMEGC and ectopic pancreas.展开更多
The power factor is the ratio between the active and apparent power,and it is available to determine the operational capability of the intended circuit or the parts.The excitation current of the synchronous motor is a...The power factor is the ratio between the active and apparent power,and it is available to determine the operational capability of the intended circuit or the parts.The excitation current of the synchronous motor is an essential parameter required for adjusting the power factor because it determines whether the motor is under the optimal operating status.Although the excitation current should predict with the experimental devices,such a method is unsuitable for online real-time prediction.The artificial intelligence algorithm can compensate for the defect of conventional measurement methods requiring the measuring devices and the model optimization is compared during the research process.In this article,the load current,power factor,and power factor errors available in the existing dataset are used as the input parameters for training the proposed artificial intelligence algorithms to select the optimal algorithm according to the training result,for this algorithm to have higher accuracy.The SMOGN(Synthetic Minority Over-Sampling Technique for Regression with Gaussian Noise)is selected for the research by which the data and the MFO(Moth-flame optimization algorithm)are created for the model to adjust and optimize the parameters automatically.In addition to enhancing the prediction accuracy for the excitation current,the automatic parameter adjusting method also allows the researchers not specializing in the professional algorithm to apply such application method more efficiently.The final result indicated that the prediction accuracy has reached“Mean Absolute Error(MAE)=0.0057,Root Mean Square Error(RMSE)=0.0093 andR2 score=0.9973”.Applying this method to themotor control would be much easier for the power factor adjustment in the future because it allows the motor to operate under the optimal power status to reduce energy consumption while enhancing working efficiency.展开更多
BACKGROUND One of the major perioperative complications for coronary artery bypass graft(CABG)is stroke.The risk of perioperative stroke after CABG is approximately 2%.Carotid stenosis(CS)is considered an independent ...BACKGROUND One of the major perioperative complications for coronary artery bypass graft(CABG)is stroke.The risk of perioperative stroke after CABG is approximately 2%.Carotid stenosis(CS)is considered an independent predictor of perioperative stroke risk in CABG patients.The optimal management of such patients has been a source of controversy.One of the possible surgical options is synchronous carotid endarterectomy(CEA)and CABG.Here,we have presented 4 cases of successful synchronous CEA and CABG.Our center’s experience with 4 cases of significant carotid artery stenosis,which were successfully managed with combined CEA and CABG,are detailed.The first case was a female who presented for CABG after a ST-elevation myocardial infarction.She had right internal carotid artery(ICA)occlusion and 90%left ICA stenosis.The second case was a male who was electively admitted for CABG.It was discovered that he had left ICA occlusion and 90%right ICA stenosis.The third case was a male with a history of stroke,two months prior to admission.He presented with non-ST-elevation myocardial infarction.Preoperatively,it was discovered that he had>90%right ICA stenosis.The final case was a male who was electively admitted for CABG.It was discovered that he had bilateral>90%ICA stenosis.We have also reviewed the current evidence and guidelines for managing CS in patients undergoing CABG.CONCLUSION Our case series demonstrated that synchronous CEA and CABG was safe.A multicenter study with additional patients is needed.It is necessary for clinicians to screen for CS in high-risk patients with features.展开更多
BACKGROUND The multidisciplinary team(MDT)has been carried out in many large hospitals now.However,given the costs of time and money and with little strong evidence of MDT effectiveness being reported,critiques of MDT...BACKGROUND The multidisciplinary team(MDT)has been carried out in many large hospitals now.However,given the costs of time and money and with little strong evidence of MDT effectiveness being reported,critiques of MDTs persist.AIM To evaluate the effects of MDTs on patients with synchronous colorectal liver metastases and share our opinion on management of synchronous colorectal liver metastases.METHODS In this study we collected clinical data of patients with synchronous colorectal liver metastases from February 2014 to February 2017 in the Chinese People’s Liberation Army General Hospital and subsequently divided them into an MDT+group and an MDT-group.In total,93 patients in MDT+group and 169 patients in MDT-group were included totally.RESULTS Statistical increases in the rate of chest computed tomography examination(P=0.001),abdomen magnetic resonance imaging examination(P=0.000),and preoperative image staging(P=0.0000)were observed in patients in MDT+group.Additionally,the proportion of patients receiving chemotherapy(P=0.019)and curative resection(P=0.042)was also higher in MDT+group.Multivariable analysis showed that the population of patients assessed by MDT meetings had higher 1-year[hazard ratio(HR)=0.608,95%confidence interval(CI):0.398-0.931,P=0.022]and 5-year(HR=0.694,95%CI:0.515-0.937,P=0.017)overall survival.CONCLUSION These results proved that MDT management did bring patients with synchronous colorectal liver metastases more opportunities for comprehensive examination and treatment,resulting in better outcomes.展开更多
基金supported by the Science and Technology Project of State Grid Corporation of China(5100202199536A-0-5-ZN)。
文摘The penetration of new energy sources such as wind power is increasing,which consequently increases the occurrence rate of subsynchronous oscillation events.However,existing subsynchronous oscillation source-identification methods primarily analyze fixed-mode oscillations and rarely consider time-varying features,such as frequency drift,caused by the random volatility of wind farms when oscillations occur.This paper proposes a subsynchronous oscillation sourcelocalization method that involves an enhanced short-time Fourier transform and a convolutional neural network(CNN).First,an enhanced STFT is performed to secure high-resolution time-frequency distribution(TFD)images from the measured data of the generation unit ports.Next,these TFD images are amalgamated to form a subsynchronous oscillation feature map that serves as input to the CNN to train the localization model.Ultimately,the trained CNN model realizes the online localization of subsynchronous oscillation sources.The effectiveness and accuracy of the proposed method are validated via multimachine system models simulating forced and natural oscillation events using the Power Systems Computer Aided Design platform.Test results show that the proposed method can localize subsynchronous oscillation sources online while considering unpredictable fluctuations in wind farms,thus providing a foundation for oscillation suppression in practical engineering scenarios.
文摘Permanent magnet synchronous motor(PMSM)speed control systems with conventional linear active disturbance rejection control(CLADRC)strategy encounter issues regarding the coupling between dynamic response and disturbance suppression and have poor performance in suppressing complex nonlinear disturbances.In order to address these issues,this paper proposes an improved two-degree-of-freedom LADRC(TDOF-LADRC)strategy,which can enhance the disturbance rejection performance of the system while decoupling entirely the system's dynamic and anti-disturbance performance to boost the system robustness and simplify controller parameter tuning.PMSM models that consider total disturbances are developed to design the TDOF-LADRC speed controller accurately.Moreover,to evaluate the control performance of the TDOF-LADRC strategy,its stability is proven,and the influence of each controller parameter on the system control performance is analyzed.Based on it,a comparison is made between the disturbance observation ability and anti-disturbance performance of TDOF-LADRC and CLADRC to prove the superiority of TDOF-LADRC in rejecting disturbances.Finally,experiments are performed on a 750 W PMSM experimental platform,and the results demonstrate that the proposed TDOF-LADRC exhibits the properties of two degrees of freedom and improves the disturbance rejection performance of the PMSM system.
文摘In this editorial we comment on the manuscript,describing management and surveillance strategies in synchronous and metachronous,gastric and colon cancers.Synchronous or metachronous primary malignancies at different sites of the gastrointestinal tract pose a unique diagnostic and therapeutic challenge.Multidisciplinary services and strategies are required for the management of multiple site primary malignancies,to provide the best oncological outcomes.Although this study highlights the dual cancers in 76 sporadic cases,the authors excluded 55 patients due to combination of factors which includes;incomplete clinical data,genetic syndrome,gastric stump cancers.In addition,the authors did not elaborate if any patients presented with signet ring cell morphology,E-cadherin mutations or presence of inflammatory bowel disease.Genetic and mutational errors and epithelial field defects from chronic inflammatory diseases of the gastrointestinal tract are important when considering synchronous gastric and colonic cancers.We will briefly discuss these in this editorial.
基金funded by the National Natural Science Foundation of China(52067013),and the Provincial Natural Science Foundation of Gansu(20JR5RA395).
文摘In the DC microgrid,the lack of inertia and damping in power electronic converters results in poor stability of DC bus voltage and low inertia of the DC microgrid during fluctuations in load and photovoltaic power.To address this issue,the application of a virtual synchronous generator(VSG)in grid-connected inverters control is referenced and proposes a control strategy called the analogous virtual synchronous generator(AVSG)control strategy for the interface DC/DC converter of the battery in the microgrid.Besides,a flexible parameter adaptive control method is introduced to further enhance the inertial behavior of the AVSG control.Firstly,a theoretical analysis is conducted on the various components of the DC microgrid,the structure of analogous virtual synchronous generator,and the control structure’s main parameters related to the DC microgrid’s inertial behavior.Secondly,the voltage change rate tracking coefficient is introduced to adjust the change of the virtual capacitance and damping coefficient flexibility,which further strengthens the inertia trend of the DC microgrid.Additionally,a small-signal modeling approach is used to analyze the approximate range of the AVSG’s main parameters ensuring system stability.Finally,conduct a simulation analysis by building the model of the DC microgrid system with photovoltaic(PV)and battery energy storage(BES)in MATLAB/Simulink.Simulation results from different scenarios have verified that the AVSG control introduces fixed inertia and damping into the droop control of the battery,resulting in a certain level of inertia enhancement.Furthermore,the additional adaptive control strategy built upon the AVSG control provides better and flexible inertial support for the DC microgrid,further enhances the stability of the DC bus voltage,and has a more positive impact on the battery performance.
基金Supported by National Natural Science Foundation of China,No.82070684the Fundamental and Applied Basic Research Program of Guangdong Province,No.2020B151502005+3 种基金the Bethune Aixikang Distinguished Surgical Fund project,No.HZB-20190528-5China international medical foundation,No.Z-2017-24-2110the Program of Guangdong Provincial Clinical Research Center for Digestive Diseases,No.2020B1111170004the National Key Clinical Discipline.
文摘BACKGROUND Studies evaluating the characteristics of dual primary gastric and colorectal cancer(CRC)(DPGCC)are limited.AIM To analyze the clinicopathologic characteristics and prognosis of synchronous and metachronous cancers in patients with DPGCC.METHODS From October 2010 to August 2021,patients with DPGCC were retrospectively reviewed.The patients with DPGCC were divided into two groups(synchronous and metachronous).We compared the overall survival(OS)between the groups using Kaplan-Meier survival methods.Univariate and multivariate analyses were performed using Cox’s proportional hazards model to identify the independent prognostic factors for OS.RESULTS Of the 76 patients with DPGCC,46 and 30 had synchronous and metachronous cancers,respectively.The proportion of unresectable CRC in patients with synchronous cancers was higher than that in patients with metachronous cancers(28.3%vs 3.3%,P=0.015).The majority of the second primary cancers had occurred within 5 years.Kaplan-Meier survival analysis showed that the patients with metachronous cancers had a better prognosis than patients with synchronous cancers(P=0.010).The patients who had undergone gastrectomy(P<0.001)or CRC resection(P<0.001)had a better prognosis than those who had not.In the multivariate analysis,synchronous cancer[hazard ratio(HR)=6.8,95%confidence interval(95%CI):2.0-22.7,(P=0.002)]and stage III-IV gastric cancer(GC)[HR=10.0,95%CI:3.4-29.5,(P<0.001)]were risk prognostic factor for OS,while patients who underwent gastrectomy was a protective prognostic factor for OS[HR=0.2,95%CI:0.1-0.6,P=0.002].CONCLUSION Regular surveillance for metachronous cancer is necessary during postoperative follow-up.Surgical resection is the mainstay of therapy to improve the prognosis of DPGCC.The prognosis appears to be influenced by the stage of GC rather than the stage of CRC.Patients with synchronous cancer have a worse prognosis,and its treatment strategy is worth further exploration.
文摘The magnetic field generated in the air gap of the cage asynchronous machine and the harmonics of the magnetomotive forces creating that magnetic field,as well as the synchronous parasitic torques,radial magnetic forces have been discussed in great detail in the literature,but always separately,for a long time.However,systematization of the phenomenon still awaits.Therefore,it is worth summarizing the completeness of the phenomena in a single study–with a new approach at the same time-in order to reveal the relationships between them.The role of rotor slot number is emphasized much more than before.New formulas derived for both synchronous torques and radial magnetic forces are used for further investigation.It will be shown that both phenomena in subject must be treated together.Formulas will be provided to take into account attenuation.Design guide will be provided to avoid dangerous rotor slot numbers.It will be shown that the generation of synchronous torques and radial magnetic forces do not depend–in this new approach-on the slot combination,but on the rotor slot number itself.
文摘In this paper, an adaptive gain tuning rule is designed for the nonlinear sliding mode speed control(NSMSC) in order to enhance the dynamic performance and the robustness of the permanent magnet assisted synchronous reluctance motor(PMa-Syn RM) with considering the parameter uncertainties. A nonlinear sliding surface whose parameters are altering with time is designed at first. The proposed NSMSC can minimize the settling time without any overshoot via utilizing a low damping ratio at starting along with a high damping ratio as the output approaches the target set-point. In addition, it eliminates the problem of the singularity with the upper bound of an uncertain term that is hard to be measured practically as well as ensures a rapid convergence in finite time, through employing a simple adaptation law. Moreover, for enhancing the system efficiency throughout the constant torque region, the control system utilizes the maximum torque per ampere technique. The nonlinear sliding surface stability is assured via employing Lyapunov stability theory. Furthermore, a simple sliding mode estimator is employed for estimating the system uncertainties. The stability analysis and the experimental results indicate the effectiveness along with feasibility of the proposed speed estimation and the NSMSC approach for a 1.1-k W PMa-Syn RM under different speed references, electrical and mechanical parameters disparities, and load disturbance conditions.
基金supported by funded by"Ye Qisun"Joint Foundation Project supported by the State Key Program of National Natural Science Foundation of China under Award U2141223.
文摘In order to enhance the transient performance of aircraft high voltage DC(HVDC)generation system with wound rotor synchronous machine(WRSM)under a wide speed range,the nonlinear PI multi-loop control strategy is proposed in this paper.Traditional voltage control method is hard to achieve the dynamic performance requirements of the HVDC generation system under a wide speed range,so the nonlinear PI parameter adjustment,load current feedback and speed feedback are added to the voltage and excitation current double loop control.The transfer function of the HVDC generation system is derived,and the relationship between speed,load current and PI parameters is obtained.The PI parameters corresponding to the load at certain speed are used to shorten the adjusting time when the load suddenly changes.The dynamic responses in transient processes are analyzed by experiment.The results illustrate that the WRSM HVDC generator system with this method has better dynamic performance.
基金supported in part by the Liaoning Provincial Department of Education Key Research Project under JYT2020160by the Liaoning Provincial Department of Education General Project under LJKZ0224。
文摘Dual three-phase Permanent Magnet Synchronous Motor(DTP-PMSM)is a nonlinear,strongly coupled,high-order multivariable system.In today’s application scenarios,it is difficult for traditional PI controllers to meet the requirements of fast response,high accuracy and good robustness.In order to improve the performance of DTP-PMSM speed regulation system,a control strategy of PI controller based on genetic algorithm is proposed.Firstly,the basic mathematical model of DTP-PMSM is established,and the PI parameters of DTP-PMSM speed regulation system are optimized by genetic algorithm,and the modeling and simulation experiments of DTP-PMSM control system are carried out by MATLAB/SIMULINK.The simulation results show that,compared with the traditional PI control,the proposed algorithm significantly improves the performance of the control system,and the speed output overshoot of the GA-PI speed control system is smaller.The anti-interference ability is stronger,and the torque and double three-phase current output fluctuations are smaller.
基金the support of the National Natural Science Foundation of China(Grant Nos.42207199,52179113,42272333)Zhejiang Postdoctoral Scientific Research Project(Grant Nos.ZJ2022155,ZJ2022156)。
文摘In areas with seasonal freezing,when the tunnel lining concrete is saturated with water infiltrating the interior,the lining and the surrounding rocks will simultaneously freeze.However,the current calculation of the frost heaving force fails to consider the synchronous damage to the lining and surrounding rocks under freeze-thaw cycles.Therefore,as per the elastic calculation model of the frost heaving force and model of steady-state heat transfer of circular tunnels,this study introduces the frost heaving rate of lining and surrounding rocks.First,the analytical solution of frost heaving force is obtained for simultaneous frost heaving of lining and surrounding rocks under any steady-state temperature field.Then,based on the fracture theory and meso-damage mechanics,the damage variables of lining and surrounding rocks under freeze-thaw cycles are extracted,representing their elastic modulus and porosity.Finally,the formula of frost heaving force for synchronous damage to the lining and surrounding rocks at any steady-state temperature field is obtained.The calculation results demonstrate that the lower the temperature inside the lining,the greater the frost heaving force.With the increasing number of freeze-thaw cycles,frost heaving force tends to gradually increase initially,reaching a peak value at 85 freeze-thaw cycles,decreasing to 80%of the peak value at 140 cycles before reaching a constant value.The lining participates in frost heaving,increasing the frost heaving force.The initial increase rate of frost heaving force is 15.7%.Changing the fitting coefficients s1 and s2 of the lining and surrounding rocks can effectively control the magnitude of the frost heaving force in the tunnels.
文摘An improved rheo-optic in situ synchronous measurement system was employed to investigate the gelation behaviour and mechanism of waxy crude oil emulsions. By combining transmitted natural light and reflected polarized light microscopy, a multiangle composite light source was built to achieve the simultaneous observation of wax crystals and emulsified water droplets, as well as their dynamic aggregation process. Main outcomes on the microscopic mechanism were obtained by developed microscopic image processing method. It was found that the microstructure of W/O waxy crude oil emulsion has the evolution of “individual structure--homogeneous aggregate structure--heterogeneous coaggregate structure--floc structure” during the static cooling, which results in the four stages during gelation process. Different from previous studies, the aggregation of emulsified water droplets was found to be more significant and contributes to the formation and development of the wax crystals-emulsified water droplets coaggregate, which plays a decisive role in the further evolution of the gelled microstructure. Time series microscopic images show the dynamic aggregation of emulsified water droplets and wax crystals. Two different aggregation behaviours between wax crystals and water droplets were observed. That wax crystals can not only embed in gaps between adjacent water droplets and enhance the structure, but also surround the outside of the water droplets and continue to grow resulting in the interconnection of different coaggregates to form a larger floc structure. In addition, correlation between viscoelasticity and microstructure evolution of waxy crude oil emulsions of different water contents was discussed. With increasing water contents, the microstructure is changed from wax crystal flocculation structure as the main skeleton and the emulsified water droplets embedded in it, into the aggregation of emulsified water droplets occupying the main position. When the number of wax crystals and water droplets reaches a certain ratio, did wax crystals form coaggregates with emulsified water droplets, and the remaining wax crystals formed an overall flocculation structure, the viscoelasticity of the waxy crude oil emulsion is the highest.
基金Supported by National Postdoctoral Program for Innovative Talent of China (Grant No.BX20180031)。
文摘Periodic components are of great significance for fault diagnosis and health monitoring of rotating machinery.Time synchronous averaging is an effective and convenient technique for extracting those components.However,the performance of time synchronous averaging is seriously limited when the separate segments are poorly synchronized.This paper proposes a new averaging method capable of extracting periodic components without external reference and an accurate period to solve this problem.With this approach,phase detection and compensation eliminate all segments'phase differences,which enables the segments to be well synchronized.The effectiveness of the proposed method is validated by numerical and experimental signals.
基金Shanxi Soft Science General Program,No.2018041032-2.
文摘BACKGROUND Multiple primary malignant neoplasms(MPMNs)are rare,while synchronous MPMNs(SMPMNs)are even less common.Owing to the progression of medical technology and the extension of life expectancy,its incidence is gradually increasing.CASE SUMMARY Although reports of breast and thyroid dual cancers are common,cases of an additional diagnosis of kidney primary cancer within the same individual are rare.CONCLUSION We present a case of simultaneous MPMN of three endocrine organs,reviewing the relevant literature to enhance our understanding of SMPMNs while emphasizing the increasingly important need for accurate diagnosis and multidisciplinary management whenever this challenging situation arises.
文摘BACKGROUND Synchronous colorectal carcinomas(SCRC)are two or more primary colorectal carcinomas identified simultaneously or within 6 mo of the initial presentation in a single patient.Their incidence is low and the number of pathological types of SCRC is usually no more than two.It is very unusual that the pathological findings of a patient with SCRC show more than two different pathological subtypes.Here,we report a rare case of SCRC with three pathological subtypes.CASE SUMMARY A 75-year-old woman who had no previous medical history or family history was admitted to the hospital because of intermittent hematochezia for more than a month.Colonoscopy displayed an irregularly shaped neoplasm of the rectum,a tumor-like lesion causing intestinal stenosis in the descending colon,and a polypoidal neoplasm in the ileocecum.Subsequently,she underwent total colectomy,abdominoperineal resection for rectal cancer,and ileostomy.After operation,the pathological report showed three pathological subtypes including well-differentiated adenocarcinoma of the ascending colon,moderately differen-tiated adenocarcinoma of the descending colon,and mucinous adenocarcinoma of the rectum.She is now recovering well and continues to be closely monitored during follow-up.CONCLUSION Preoperative colonoscopy examination,imaging examination,and extensive intraoperative exploration play important roles in reducing the number of missed lesions.
文摘BACKGROUND To evaluate the clinicopathological features and prognosis of gastric cancer(GC)occurring synchronously with gastrointestinal stromal tumor(GIST).CASE SUMMARY We report 19 patients with concurrent GC and GIST(17 male and 2 female,median age 62 years).GC was most often located in the lower third of the stomach.GIST was diagnosed preoperatively in four patients.GIST was most often located in the gastric body(n=8,42%).The most common growth pattern in GIST was extraluminal(n=12,63%).The positive expression rates of CD117 and CD34 in GIST were 100% and 95%,respectively.Most patients with GIST(n=17,89%)were very low or low risk.There was no recurrence of GIST during follow-up.The 3-year cumulative survival rate was 73.9%,and the 5-year cumulative survival rate was 59.2%.The combined analysis of this study and literature reports(47 reports,157 patients)found that GC and GIST were usually located in the lower third(42%)and middle third(51%)of the stomach.GC was usually early(stage I:42%),poorly differentiated(42%)intestinal-type adenocarcinoma(51%).GISTs were primarily small in diameter(median:1.2 cm)and very low or low risk(89%).CONCLUSION Synchronous GC and GIST may not be rare.They have specific clinicopathological characteristics,and may have mutual inhibition in pathogenesis and progression.
文摘High rates of extrapancreatic malignancies,in particular colorectal cancer(CRC),have been detected in patients with intraductal papillary mucinous neoplasm(IPMN).So far,there is no distinct explanation in the literature for the development of secondary or synchronous malignancies in patients with IPMN.In the past few years,some data related to common genetic alterations in IPMN and other affiliated cancers have been published.This review elucidated the association between IPMN and CRC,shedding light on the most relevant genetic alterations that may explain the possible relationship between these entities.In keeping with our findings,we suggested that once the diagnosis of IPMN is made,special consideration of CRC should be undertaken.Presently,there are no specific guidelines regarding colorectal screening programs for patients with IPMN.We recommend that patients with IPMNs are at high-risk for CRC,and a more rigorous colorectal surveillance program should be implemented.
文摘BACKGROUND A large percentage of patients with ectopic pancreas are asymptomatic.When present,the symptoms are typically non-specific.These lesions are predominantly located in the stomach and benign in nature.Synchronous multiple early gastric cancer(SMEGC)(two or more simultaneous malignant lesions with early gastric cancer)is relatively rare and particularly easy to overlook during endoscopic examination.The prognosis of SMEGC is generally poor.We report a rare case of ectopic pancreas with concomitant SMEGC.CASE SUMMARY A 74-year-old woman presented with paroxysmal upper abdominal pain.On initial investigations,she tested positive for Helicobacter pylori(H.pylori).She underwent esophagogastroduodenoscopy which revealed a 1.5 cm×2 cm major lesion at the greater curvature and a 1 cm minor lesion at the lesser curvature of the stomach.On endoscopic ultrasound,the major lesion showed hypoechoic changes,uneven internal echoes and unclear boundaries between some areas and the muscularis propria.Endoscopic submucosal dissection was performed to excise the minor lesion.A laparoscopic resection was chosen for the major lesion.On histopathological examination,the major lesion contained high grade intraepithelial neoplasia with a small focus of cancer.A separate underlying ectopic pancreas was found under this lesion.The minor lesion contained high grade intraepithelial neoplasia.In this case,the patient was diagnosed with SMEGC with concomitant ectopic pancreas in the stomach.CONCLUSION Patients with atrophy,H.pylori,and other risk factors should be carefully investigated to avoid missing other lesions including SMEGC and ectopic pancreas.
基金This work was supported by the Ministry of Science and Technology,Taiwan,under Grants MOST 110-2221-E-194-037,NSTC 111-2823-8-194-002,111-2221-E-194-052 and 11-2218-E-194-007。
文摘The power factor is the ratio between the active and apparent power,and it is available to determine the operational capability of the intended circuit or the parts.The excitation current of the synchronous motor is an essential parameter required for adjusting the power factor because it determines whether the motor is under the optimal operating status.Although the excitation current should predict with the experimental devices,such a method is unsuitable for online real-time prediction.The artificial intelligence algorithm can compensate for the defect of conventional measurement methods requiring the measuring devices and the model optimization is compared during the research process.In this article,the load current,power factor,and power factor errors available in the existing dataset are used as the input parameters for training the proposed artificial intelligence algorithms to select the optimal algorithm according to the training result,for this algorithm to have higher accuracy.The SMOGN(Synthetic Minority Over-Sampling Technique for Regression with Gaussian Noise)is selected for the research by which the data and the MFO(Moth-flame optimization algorithm)are created for the model to adjust and optimize the parameters automatically.In addition to enhancing the prediction accuracy for the excitation current,the automatic parameter adjusting method also allows the researchers not specializing in the professional algorithm to apply such application method more efficiently.The final result indicated that the prediction accuracy has reached“Mean Absolute Error(MAE)=0.0057,Root Mean Square Error(RMSE)=0.0093 andR2 score=0.9973”.Applying this method to themotor control would be much easier for the power factor adjustment in the future because it allows the motor to operate under the optimal power status to reduce energy consumption while enhancing working efficiency.
文摘BACKGROUND One of the major perioperative complications for coronary artery bypass graft(CABG)is stroke.The risk of perioperative stroke after CABG is approximately 2%.Carotid stenosis(CS)is considered an independent predictor of perioperative stroke risk in CABG patients.The optimal management of such patients has been a source of controversy.One of the possible surgical options is synchronous carotid endarterectomy(CEA)and CABG.Here,we have presented 4 cases of successful synchronous CEA and CABG.Our center’s experience with 4 cases of significant carotid artery stenosis,which were successfully managed with combined CEA and CABG,are detailed.The first case was a female who presented for CABG after a ST-elevation myocardial infarction.She had right internal carotid artery(ICA)occlusion and 90%left ICA stenosis.The second case was a male who was electively admitted for CABG.It was discovered that he had left ICA occlusion and 90%right ICA stenosis.The third case was a male with a history of stroke,two months prior to admission.He presented with non-ST-elevation myocardial infarction.Preoperatively,it was discovered that he had>90%right ICA stenosis.The final case was a male who was electively admitted for CABG.It was discovered that he had bilateral>90%ICA stenosis.We have also reviewed the current evidence and guidelines for managing CS in patients undergoing CABG.CONCLUSION Our case series demonstrated that synchronous CEA and CABG was safe.A multicenter study with additional patients is needed.It is necessary for clinicians to screen for CS in high-risk patients with features.
文摘BACKGROUND The multidisciplinary team(MDT)has been carried out in many large hospitals now.However,given the costs of time and money and with little strong evidence of MDT effectiveness being reported,critiques of MDTs persist.AIM To evaluate the effects of MDTs on patients with synchronous colorectal liver metastases and share our opinion on management of synchronous colorectal liver metastases.METHODS In this study we collected clinical data of patients with synchronous colorectal liver metastases from February 2014 to February 2017 in the Chinese People’s Liberation Army General Hospital and subsequently divided them into an MDT+group and an MDT-group.In total,93 patients in MDT+group and 169 patients in MDT-group were included totally.RESULTS Statistical increases in the rate of chest computed tomography examination(P=0.001),abdomen magnetic resonance imaging examination(P=0.000),and preoperative image staging(P=0.0000)were observed in patients in MDT+group.Additionally,the proportion of patients receiving chemotherapy(P=0.019)and curative resection(P=0.042)was also higher in MDT+group.Multivariable analysis showed that the population of patients assessed by MDT meetings had higher 1-year[hazard ratio(HR)=0.608,95%confidence interval(CI):0.398-0.931,P=0.022]and 5-year(HR=0.694,95%CI:0.515-0.937,P=0.017)overall survival.CONCLUSION These results proved that MDT management did bring patients with synchronous colorectal liver metastases more opportunities for comprehensive examination and treatment,resulting in better outcomes.
