Objective: To investigate the operative timing and indi-cations for severe acute pancreatitis(SAP).Methods: Data collected from 172 patients with SAPtreated in our hospital since 1980 were analyzed retro-spectively.Re...Objective: To investigate the operative timing and indi-cations for severe acute pancreatitis(SAP).Methods: Data collected from 172 patients with SAPtreated in our hospital since 1980 were analyzed retro-spectively.Results: In the 94 patients who had undergone early op-eration before June 1992, 57 (62.8%) healed, 35 (37.2%)died, and 16 (17.0%) had no postoperative compli-cations. In the 78 patients who had been treated after July1992 according to the principle of individualization, 66(84.6%) healed, 12 (15.4%) died, and 37 (47.4%)had no postoperative complications. In the 78 patients32 received non-operative treatment but 30 (93.8%)cured, 12 early operation but 7(58.3%)cured, 18 lateoperation but 13 (72.2%) cured, and 16 selected timeoperation but all cured.Conclusions: It is concluded that individualized thera-py is effective and reasonable for treating SAP. Theindications for early, late and selected time operationshould be emphasized.展开更多
Objective To study the effect of operative timing on clinical outcomes in elderly hip fracture.Methods Two hundred sixty-seven patients with hip fracture were treated from July 2006 to May 2008.The patients who had an...Objective To study the effect of operative timing on clinical outcomes in elderly hip fracture.Methods Two hundred sixty-seven patients with hip fracture were treated from July 2006 to May 2008.The patients who had an operation within展开更多
BACKGROUND: Fulminant hepatic failure manifests a rapid onset, serious complications, and a high mortality, but still there is a possibility of recovery. Once the patient is able to pass a crisis, the liver is able to...BACKGROUND: Fulminant hepatic failure manifests a rapid onset, serious complications, and a high mortality, but still there is a possibility of recovery. Once the patient is able to pass a crisis, the liver is able to regenerate completely and regain its normal function. Therefore it is of vital importance to determine the eligible timing for transplantation. Premature surgery might result in a loss of the chance of internal medical treatment and misuse of liver resources, whereas delayed surgery might increase the difficulty of treatment in the preoperative period and the possibility of complications and medical expense, which eventually result in decreased rate of success and survival. This problem remains worldwide how to choose the optional timing of operation. METHODS: Thirty-six patients with severe hepatitis were treated by orthotopic liver transplantation. The distribution of MELD scores in these patients was: 10-19 in 8 patients, 20-29 in 10, 30-39 in 11, and 40 in 7. They were divided into two groups: MELD score <30 and MELD score >= 30. Parameters (1-year survival rate, complications, preoperative use of artificial liver, operative time, volume of bleeding and blood transfusion, and average hospital costs) were examined as prognostic factors after liver transplantation. RESULTS: The I-year survival rate of the MELD score <30 group was higher than that of the >= 30 group (77.8% and 33.3%, P=0.007), and the rate of complications in the <30 group was lower (P=0.012). There were no differences in the timing of artificial liver treatment, operative time, operative hemorrhage, and transfusion between the two groups (P=0.742). But the average daily hospital cost in the MELD score >= 30 group was higher (P=0.008). CONCLUSION: This study shows that when the MELD score is <30 it may be the optimal time to perform liver transplantation for patients with severe hepatitis.展开更多
Objective:Radical cystectomy is a complex lengthy procedure associated with postoperative morbidity.We aimed to assess the operative time(OT)in patients undergoing radical cystectomy and its impact on 90-day postopera...Objective:Radical cystectomy is a complex lengthy procedure associated with postoperative morbidity.We aimed to assess the operative time(OT)in patients undergoing radical cystectomy and its impact on 90-day postoperative complications and readmission rates.Methods:The retrospective cohort study included 296 patients undergoing radical cystectomy and urinary diversion from May 2010 to December 2018 in our institution.The OT of 369 min was set as a cutoff value between short and long OT groups.The primary outcome was 90-day postoperative complication rates.Secondary outcomes were gastrointestinal recovery time,length of hospital stay,and 90-day readmission rates.Results:The overall incidence of 90-day postoperative complications was 79.7%where 43.2%representing low-grade complications according to the ClavieneDindo classification(Grade 1 and Grade 2),and 36.5%representing high-grade complications(Grade3).Gastrointestinal tract and infectious complications are the most common complications in our data set(45.9%and 45.6%,respectively).On multivariable analysis,prolonged OT was significantly associated with odds of high-grade complications(odds ratio 2.340,95%confidence interval 1.288e4.250,p=0.005).After propensity score-matched analysis,a higher incidence of major complications was identified in the long OT group 55(51.4%)compared to 35(32.7%)in the short OT group(p=0.006).A shorter gastrointestinal tract recovery time was noticed in the short OT group(p=0.009).Prolonged OT was associated with a higher 90-day readmission rate on univariate and multivariate analyses(p<0.001,p=0.001,respectively).展开更多
Objective:To investigate the clinical efficacy and safety of percutaneous kyphoplasty at different surgical timings in the treatment of osteoporotic vertebral compression fracture(OVCF)based on the theory of“dynamic-...Objective:To investigate the clinical efficacy and safety of percutaneous kyphoplasty at different surgical timings in the treatment of osteoporotic vertebral compression fracture(OVCF)based on the theory of“dynamic-static integration”.Methods:Patients with OVCF who underwent percutaneous kyphoplasty in our hospital were selected and divided into Groups A,B,and C for those undergoing surgery within 7,7—21,and>21 days of fracture occurrence.The variations in the amount of bone cement injected,pre-and post-operative pain levels,functional activity,deformity correction of the injured vertebrae,bone cement leakage,and vertebral body height loss were compared among the three groups.Results:Regarding pain relief and functional activity,the postoperative Visual Analog Scale and Oswestry Disability Index scores of the three groups significantly improved.Furthermore,the deformities of the injured vertebrae in the three groups were significantly corrected,with Groups A and B exhibiting superior correction compared to Group C.Moreover,the bone cement leakage rates in groups A and C were higher than that in Group B.At the 3-month follow-up,the loss of vertebral height in Group C was significantly higher than those in groups A and B.Conclusion:Kyphoplasty is effective for OVCF treatment.Early surgery can effectively restore the vertebral height of the injured vertebra,reduce kyphosis,and reduce height loss of the injured vertebra after surgery;nevertheless,treatment within 1—3 weeks of the fracture can reduce the occurrence of bone cement leakage,making the surgery safer.Therefore,surgical treatment within 1—3 weeks of fracture is safer and can achieve satisfactory therapeutic effects.From the perspective of traditional Chinese medicine,PKP surgery can transform the fracture end from a micromotion state to a fixed state,which fully embodies the theory of“dynamic-static integration”.展开更多
In order to improve network connectivity in clustered wireless sensor networks,a node cooperative algorithm based on virtual antenna arrays is proposed.All the nodes in the network are assumed to be clustered via Pois...In order to improve network connectivity in clustered wireless sensor networks,a node cooperative algorithm based on virtual antenna arrays is proposed.All the nodes in the network are assumed to be clustered via Poisson Voronoi tessellation（PVT）.The activation of the node cooperative algorithm is determined by the cluster heads（CHs） according to communication links.When the cooperative algorithm is activated,the CH selects cooperative nodes（CNs） from its members to form a virtual antenna array.With the cooperation,nodes can extend the inter-cluster communication range to directly contact with further nodes after a coverage hole is detected,or compensate for channel gains while inter-cluster transmission fails due to deep channel fading.Simulation results show that the proposed algorithm achieves better network connectivity and energy efficiency.It can reduce outage probability,sustain network connectivity and maintain operations as long as possible,which prolongs network operation time.展开更多
BACKGROUND Endoscopic submucosal dissection(ESD)is a treatment for early gastric cancer with the advantages of small invasion,fewer complications,and a low local recurrence rate.However,there is a high risk of complic...BACKGROUND Endoscopic submucosal dissection(ESD)is a treatment for early gastric cancer with the advantages of small invasion,fewer complications,and a low local recurrence rate.However,there is a high risk of complications such as bleeding and perforation,and the operation time is also longer.ESD operation time is closely related to bleeding and perforation.AIM To investigate the influencing factors associated with ESD operation time and postoperative delayed hemorrhage to provide a reference for early planning,early identification,and prevention of complications.METHODS We conducted a retrospective study based on the clinical data of 520 patients with early gastric cancer in the Second Affiliated Hospital of Hainan Medical University from January 2019 to December 2021.The baseline data,clinical features,and endoscopic and pathological characteristics of patients were collected.The multivariate linear regression model was used to investigate the influencing factors of ESD operation time.Logistic regression analysis was carried out to evaluate the influencing factors of postoperative delayed hemorrhage.RESULTS The multivariate analysis of ESD operation time showed that the maximum lesion diameter could affect 8.815%of ESD operation time when other influencing factors remained unchanged.The operation time increased by 3.766%or 10.247%if the lesion was mixed or concave.The operation time increased by 4.417%if combined with an ulcer or scar.The operation time increased by 3.692%if combined with perforation.If infiltrated into the submucosa,it increased by 2.536%.Multivariate analysis of delayed hemorrhage after ESD showed that the maximum diameter of the lesion,lesion morphology,and ESD operation time were independent influencing factors for delayed hemorrhage after ESD.Patients with lesion≥3.0 cm(OR=3.785,95%CI:1.165-4.277),lesion morphology-concave(OR=10.985,95%CI:2.133-35.381),and ESD operation time≥60 min(OR=2.958,95%CI:1.117-3.526)were prone to delayed hemorrhage after ESD.CONCLUSION If the maximum diameter of the lesion in patients with early gastric cancer is≥3.0 cm,and the shape of the lesion is concave,or accompanied by an ulcer or scar,combined with perforation,and infiltrates into the submucosa,the ESD operation will take a longer time.When the maximum diameter of the lesion is≥3.0 cm,the shape of the lesion is concave in patients and the operation time of ESD takes longer time,the risk of delayed hemorrhage after ESD is higher.展开更多
Objective:While a rushed operation can omit essential procedures,prolonged operative time results in higher morbidity.Nevertheless,the optimal operative time range remains uncertain.This study aimed to estimate the id...Objective:While a rushed operation can omit essential procedures,prolonged operative time results in higher morbidity.Nevertheless,the optimal operative time range remains uncertain.This study aimed to estimate the ideal operative time range and evaluate its applicability in laparoscopic cancer surgery.Methods:A prospectively collected multicenter database of 397 patients who underwent laparoscopic distal gastrectomy were retrospectively reviewed.The ideal operative time range was statistically calculated by separately analyzing the operative time of uneventful surgeries.Finally,intraoperative and postoperative outcomes were compared among the shorter,ideal,and longer operative time groups.Results:The statistically calculated ideal operative time was 135.4-165.4 min.The longer operative time(LOT)group had a lower rate of uneventful,perfect surgery than the ideal or shorter operative time(IOT/SOT)group(2.8%vs.8.8%and 2.2%vs.13.4%,all P<0.05).Longer operative time increased bleeding,postoperative morbidities,and delayed diet and discharge(all P<0.05).Particularly,an uneventful,perfect surgery could not be achieved when the operative time exceeded 240 min.Regardless of ideal time range,SOT group achieved the highest percentage of uneventful surgery(13.4%),which was possible by surgeon's ability to retrieve a higher number of lymph nodes and perform≥150 gastrectomies annually.Conclusions:Operative time longer than the ideal time range(especially≥240 min)should be avoided.If the essential operative procedure were faithfully conducted without compromising oncological safety,an operative time shorter than the ideal range leaded to a better prognosis.Efforts to minimize operative time should be attempted with sufficient surgical experience.展开更多
BACKGROUND Pancreatic adenocarcinoma is currently the fourth leading cause of cancer-related deaths in the United States.In patients with“borderline resectable”disease,current National Comprehensive Cancer Center gu...BACKGROUND Pancreatic adenocarcinoma is currently the fourth leading cause of cancer-related deaths in the United States.In patients with“borderline resectable”disease,current National Comprehensive Cancer Center guidelines recommend the use of neoadjuvant chemoradiation prior to a pancreaticoduodenectomy.Although neoadjuvant radiotherapy may improve negative margin resection rate,it is theorized that its administration increases operative times and complexity.AIM To investigate the association between neoadjuvant radiotherapy and 30-d morbidity and mortality outcomes among patients receiving a pancreaticoduodenectomy for pancreatic adenocarcinoma.METHODS Patients listed in the 2015-2019 National Surgery Quality Improvement Program data set,who received a pancreaticoduodenectomy for pancreatic adenocarcinoma,were divided into two groups based off neoadjuvant radiotherapy status.Multivariable regression was used to determine if there is a significant correlation between neoadjuvant radiotherapy,perioperative blood transfusion status,total operative time,and other perioperative outcomes.RESULTS Of the 11458 patients included in the study,1470(12.8%)underwent neoadjuvant radiotherapy.Patients who received neoadjuvant radiotherapy were significantly more likely to require a perioperative blood transfusion[adjusted odds ratio(aOR)=1.58,95%confidence interval(CI):1.37-1.82;P<0.001]and have longer surgeries(insulin receptor-related receptor=1.14,95%CI:1.11-1.16;P<0.001),while simultaneously having lower rates of organ space infections(aOR=0.80,95%CI:0.66-0.97;P=0.02)and pancreatic fistula formation(aOR=0.50,95%CI:0.40-0.63;P<0.001)compared to those who underwent surgery alone.CONCLUSION Neoadjuvant radiotherapy,while not associated with increased mortality,will impact the complexity of surgical resection in patients with pancreatic adenocarcinoma.展开更多
BACKGROUND Timing of invasive intervention such as operative pancreatic debridement(OPD)in patients with acute necrotizing pancreatitis(ANP)is linked to the degree of encapsulation in necrotic collections and controll...BACKGROUND Timing of invasive intervention such as operative pancreatic debridement(OPD)in patients with acute necrotizing pancreatitis(ANP)is linked to the degree of encapsulation in necrotic collections and controlled inflammation.Additional markers of these processes might assist decision-making on the timing of surgical intervention.In our opinion,it is logical to search for such markers among routine laboratory parameters traditionally used in ANP patients,considering simplicity and cost-efficacy of routine laboratory methodologies.AIM To evaluate laboratory variables in ANP patients in the preoperative period for the purpose of their use in the timing of surgery.METHODS A retrospective analysis of routine laboratory parameters in 53 ANP patients undergoing OPD between 2017 and 2020 was performed.Dynamic changes of routine hematological and biochemical indices were examined in the preoperative period.Patients were divided into survivors and non-survivors.Survivors were divided into subgroups with short and long post-surgery length of stay(LOS)in hospital.Correlation analysis was used to evaluate association of laboratory variables with LOS.Logistic regression was used to assess risk factors for patient mortality.RESULTS Seven patients(15%)with severe acute pancreatitis(SAP)and 46 patients(85%)with moderately SAP(MSAP)were included in the study.Median age of participants was 43.2 years;33(62.3%)were male.Pancreatitis etiology included biliary(15%),alcohol(80%),and idiopathic/other(5%).Median time from diagnosis to OPD was≥4 wk.Median postoperative LOS was at the average of 53 d.Mortality was 19%.Progressive increase of platelet count in preoperative period was associated with shortened LOS.Increased aspartate aminotransferase and direct bilirubin(DB)levels the day before the OPD along with weak progressive decrease of DB in preoperative period were reliable predictors for ANP patient mortality.CONCLUSION Multifactorial analysis of dynamic changes of routine laboratory variables can be useful for a person-tailored timing of surgical intervention in ANP patients.展开更多
Objective:To investigate the effect of body mass index(BMI)on the operation time and postoperative hospital stay for patients who underwent retroperitoneal laparoscopic decortication for a single simple renal cyst.Met...Objective:To investigate the effect of body mass index(BMI)on the operation time and postoperative hospital stay for patients who underwent retroperitoneal laparoscopic decortication for a single simple renal cyst.Methods:A retrospective cohort study was conducted among 81 patients with single simple renal cyst who had undergone retroperitoneal laparoscopic cyst decortication from January 2017 to December 2019 in Wuxi Xishan People's Hospital.All patients were divided into three groups according to BMI:normal group(BMI<25 kg/m^(2),n=44),overweight group(BMI=25-30 kg/m^(2),n=21),and obese group(BMI>30 kg/m^(2),n=16).Multiple linear regression was conducted to investigate the correlation.Results:The three groups were comparable in terms of age,gender,maximum diameter of cyst,and cyst location.In the aspect of operation time,only the patients in obese group had longer duration when compared with those in the normal group(59.1±15.7 min vs.45.2±12.8 min,p=0.001).And the patients in the obese group had significantly longer hospital stay compared with those in the normal group(6.2±1.9 d vs.5.2±0.5 d,p=0.002)and overweight group(6.2±1.9 d vs.5.0±1.0d,p=0.001).In the analysis of multiple linear regression,it was found that operation time is significantly affected by BMI and location 2,with coefficients of 1.299 and -8.646 respectively.The influence of BMI was greater than location 2(0.335 vs.-0.289).For hospital stay,only BMI had an effect on it,with a coefficient of 0.110.Conclusion:BMI was a major factor that associated with longer operation time and hospital stay in patients with retroperitoneal laparoscopic renal cyst decortication.展开更多
We characterized the dependence of the timing jitter of an InGaAs/InP single-photon avalanche diode on the excess bias voltage（V（ex）） when operated in 1-GHz sinusoidally gated mode.The single-photon avalanche diod...We characterized the dependence of the timing jitter of an InGaAs/InP single-photon avalanche diode on the excess bias voltage（V（ex）） when operated in 1-GHz sinusoidally gated mode.The single-photon avalanche diode was cooled to-30 degrees Celsius.When the V（ex） is too low（0.2 V-0.8 V） or too high（3 V-4.2 V）,the timing jitter is increased with the V（ex）,particularly at high V（ex）.While at middle V（ex）（1 V-2.8 V）,the timing jitter is reduced.Measurements of the timing jitter of the same avalanche diode with pulsed gating show that this effect is likely related to the increase of both the amplitude of the V（ex） and the width of the gate-on time.For the 1-GHz sinusoidally gated detector,the best jitter of 93 ps is achieved with a photon detection efficiency of 21.4%and a dark count rate of -2.08×10 -5 per gate at the V（ex） of 2.8 V.To evaluate the whole performance of the detector,we calculated the noise equivalent power（NEP） and the afterpulse probability（P（ap））.It is found that both NEP and P（ap） increase quickly when the V（ex） is above 2.8 V.At -2.8-V V（ex）,the NEP and P（ap） are -2.06×10-（16）W/Hz-（1/2） and 7.11%,respectively.Therefore,the detector should be operated with V（ex） of 2.8 V to exploit the fast time response,low NEP and low P（ap）.展开更多
The Balise Transmission Module(BTM)unit of the on-board train control system is a crucial component.Due to its unique installation position and complex environment,this unit has a higher fault rate within the on-board...The Balise Transmission Module(BTM)unit of the on-board train control system is a crucial component.Due to its unique installation position and complex environment,this unit has a higher fault rate within the on-board train control system.To conduct fault prediction for the BTM unit based on actual fault data,this study proposes a prediction method combining reliability statistics and machine learning,and achieves the fusion of prediction results from different dimensions through multi-method interactive validation.Firstly,a method for predicting equipment fault time targeting batch equipment is introduced.This method utilizes reliability statistics to construct a model of the remaining faultless operating time distribution considering uncertainty,thereby predicting the remaining faultless operating probability of the BTM unit.Secondly,considering the complexity of the BTM unit’s fault mechanism,the small sample size of fault cases,and the potential presence of multiple fault features in fault text records,an individual-oriented fault prediction method based on Bayesian-optimized Gradient Boosting Regression Tree(Bayes-GBRT)is proposed.This method achieves better prediction results compared to linear regression algorithms and random forest regression algorithms,with an average absolute error of only 0.224 years for predicting the fault time of this type of equipment.Finally,a multi-method interactive validation approach is proposed,enabling the fusion and validation of multi-dimensional results.The results indicate that the predicted fault time and the actual fault time conform to a log-normal distribution,and the parameter estimation results are basically consistent,verifying the accuracy and effectiveness of the prediction results.The above research findings can provide technical support for the maintenance and modification of BTM units,effectively reducing maintenance costs and ensuring the safe operation of high-speed railway,thus having practical engineering value for preventive maintenance.展开更多
The key of artificial precipitation(snowfall) operation with the silver iodide generator which was set on the windward slope of mountain was the selection of updraft time.The updraft related to the entering cloud effi...The key of artificial precipitation(snowfall) operation with the silver iodide generator which was set on the windward slope of mountain was the selection of updraft time.The updraft related to the entering cloud efficiency of effective nucleus.By contrasting and analyzing two times artificial snowfall operations,the timing of artificial precipitation(snowfall) operation with the silver iodide ground generator was discussed.By using the synoptic chart,satellite cloud chart,radar,physical quantity calculation and so on,the operation timing was determined.展开更多
BACKGROUND Peripheral lung cancer poses a substantial harm to human health,and it is easy to become exacerbated,potentially threatening the life and safety of patients AIM To assess the value of virtual bronchoscopic ...BACKGROUND Peripheral lung cancer poses a substantial harm to human health,and it is easy to become exacerbated,potentially threatening the life and safety of patients AIM To assess the value of virtual bronchoscopic navigation(VBN)combined with transbronchial ultrasound-guided sheath-guided(EBUS-GS)exploration in the diagnosis of peripheral lung cancer.METHODS A total of 236 patients with peripheral lung cancer(nodule diameter range,8-30 mm;diagnosed using high-resolution computed tomography)were selected from three centers between October 2018 and December 2019.Patients who underwent EBUS-GS exploration alone were included in a control group,and those who received VBN in combination with EBUS-GS exploration were included in an observation group.The diagnostic rate and total operating time of differentsubgroups of the two groups were compared,and the time needed to determine the lesion was recorded.RESULTS There were no significant differences in diagnosis rate or total operation time between the two groups(P>0.05),and the time needed to determine the lesion in the observation group was less than that of the control group(P<0.05).CONCLUSION The combined use of VBN and EBUS-GS exploration technology has little effect on the diagnosis rate and total operation time of peripheral lung cancer,but it significantly shortens the time needed to determine the lesion and is a valuable diagnostic method.展开更多
BACKGROUND In robot-assisted(RA)spine surgery,the relationship between the surgical outcome and the learning curve remains to be evaluated.AIM To analyze the learning curve of RA pedicle screw fixation(PSF)through fit...BACKGROUND In robot-assisted(RA)spine surgery,the relationship between the surgical outcome and the learning curve remains to be evaluated.AIM To analyze the learning curve of RA pedicle screw fixation(PSF)through fitting the operation time curve based on the cumulative summation method.METHODS RA PSFs that were initially completed by two surgeons at the Beijing Jishuitan Hospital from July 2016 to March 2019 were analyzed retrospectively.Based on the cumulative sum of the operation time,the learning curves of the two surgeons were drawn and fit to polynomial curves.The learning curve was divided into the early and late stages according to the shape of the fitted curve.The operation time and screw accuracy were compared between the stages.RESULTS The turning point of the learning curves from Surgeons A and B appeared in the 18th and 17th cases,respectively.The operation time[150(128,188)min vs 120(105,150)min,P=0.002]and the screw accuracy(87.50%vs 96.30%,P=0.026)of RA surgeries performed by Surgeon A were significantly improved after he completed 18 cases.In the case of Surgeon B,the operation time(177.35±28.18 min vs 150.00±34.64 min,P=0.024)was significantly reduced,and the screw accuracy(91.18%vs 96.15%,P=0.475)was slightly improved after the surgeon completed 17 RA surgeries.CONCLUSION After completing 17 to 18 cases of RA PSFs,surgeons can pass the learning phase of RA technology.The operation time is reduced afterward,and the screw accuracy shows a trend of improvement.展开更多
The generation of low frequency waves by a single or double wave groups incident upon two Plane beaches with the slope of 1/40 and 1/100 is investigated experimentally and numerically. A new type of wave maker signal ...The generation of low frequency waves by a single or double wave groups incident upon two Plane beaches with the slope of 1/40 and 1/100 is investigated experimentally and numerically. A new type of wave maker signal is used to generate the groups, allowing the bound long wave (set-down) to be included in the group. The experiments show that the low frequency wave is generated during breaking and propagation to the shoreline of the wave group. This process of generation and propagation of low frequency waves is simulated numerically by solving the short-wave averaged mass and momentum conservation equations. The computed and measured results are in good agreement. The mechanism of generation of low frequency waves in the surf zone is examined and discussed.展开更多
The transmission coefficients of electromagnetic （EM） waves due to a superconductor-dielectric superlattice are numerically calculated. Shift operator finite difference time domain （SO-FDTD） method is used in the ...The transmission coefficients of electromagnetic （EM） waves due to a superconductor-dielectric superlattice are numerically calculated. Shift operator finite difference time domain （SO-FDTD） method is used in the analysis. By using the SO-FDTD method, the transmission spectrum is obtained and its characteristics are investigated for different thicknesses of superconductor layers and dielectric layers, from which a stop band starting from zero frequency can be apparently observed. The relation between this low-frequency stop band and relative temperature, and also the London penetration depth at a superconductor temperature of zero degree are discussed, separately. The low-frequency stop band properties of superconductor-dielectric superlattice thus are well disclosed.展开更多
Based on the general theory of time-dependent quantum transformation, we use the 'time evolutionoperator' method to solve the single-mode time-dependent oscillator.
文摘Objective: To investigate the operative timing and indi-cations for severe acute pancreatitis(SAP).Methods: Data collected from 172 patients with SAPtreated in our hospital since 1980 were analyzed retro-spectively.Results: In the 94 patients who had undergone early op-eration before June 1992, 57 (62.8%) healed, 35 (37.2%)died, and 16 (17.0%) had no postoperative compli-cations. In the 78 patients who had been treated after July1992 according to the principle of individualization, 66(84.6%) healed, 12 (15.4%) died, and 37 (47.4%)had no postoperative complications. In the 78 patients32 received non-operative treatment but 30 (93.8%)cured, 12 early operation but 7(58.3%)cured, 18 lateoperation but 13 (72.2%) cured, and 16 selected timeoperation but all cured.Conclusions: It is concluded that individualized thera-py is effective and reasonable for treating SAP. Theindications for early, late and selected time operationshould be emphasized.
文摘Objective To study the effect of operative timing on clinical outcomes in elderly hip fracture.Methods Two hundred sixty-seven patients with hip fracture were treated from July 2006 to May 2008.The patients who had an operation within
文摘BACKGROUND: Fulminant hepatic failure manifests a rapid onset, serious complications, and a high mortality, but still there is a possibility of recovery. Once the patient is able to pass a crisis, the liver is able to regenerate completely and regain its normal function. Therefore it is of vital importance to determine the eligible timing for transplantation. Premature surgery might result in a loss of the chance of internal medical treatment and misuse of liver resources, whereas delayed surgery might increase the difficulty of treatment in the preoperative period and the possibility of complications and medical expense, which eventually result in decreased rate of success and survival. This problem remains worldwide how to choose the optional timing of operation. METHODS: Thirty-six patients with severe hepatitis were treated by orthotopic liver transplantation. The distribution of MELD scores in these patients was: 10-19 in 8 patients, 20-29 in 10, 30-39 in 11, and 40 in 7. They were divided into two groups: MELD score <30 and MELD score >= 30. Parameters (1-year survival rate, complications, preoperative use of artificial liver, operative time, volume of bleeding and blood transfusion, and average hospital costs) were examined as prognostic factors after liver transplantation. RESULTS: The I-year survival rate of the MELD score <30 group was higher than that of the >= 30 group (77.8% and 33.3%, P=0.007), and the rate of complications in the <30 group was lower (P=0.012). There were no differences in the timing of artificial liver treatment, operative time, operative hemorrhage, and transfusion between the two groups (P=0.742). But the average daily hospital cost in the MELD score >= 30 group was higher (P=0.008). CONCLUSION: This study shows that when the MELD score is <30 it may be the optimal time to perform liver transplantation for patients with severe hepatitis.
基金Earlier version of this article was presented as a poster in the bladder section:invasive(MP 13-12)AUA-2021.
文摘Objective:Radical cystectomy is a complex lengthy procedure associated with postoperative morbidity.We aimed to assess the operative time(OT)in patients undergoing radical cystectomy and its impact on 90-day postoperative complications and readmission rates.Methods:The retrospective cohort study included 296 patients undergoing radical cystectomy and urinary diversion from May 2010 to December 2018 in our institution.The OT of 369 min was set as a cutoff value between short and long OT groups.The primary outcome was 90-day postoperative complication rates.Secondary outcomes were gastrointestinal recovery time,length of hospital stay,and 90-day readmission rates.Results:The overall incidence of 90-day postoperative complications was 79.7%where 43.2%representing low-grade complications according to the ClavieneDindo classification(Grade 1 and Grade 2),and 36.5%representing high-grade complications(Grade3).Gastrointestinal tract and infectious complications are the most common complications in our data set(45.9%and 45.6%,respectively).On multivariable analysis,prolonged OT was significantly associated with odds of high-grade complications(odds ratio 2.340,95%confidence interval 1.288e4.250,p=0.005).After propensity score-matched analysis,a higher incidence of major complications was identified in the long OT group 55(51.4%)compared to 35(32.7%)in the short OT group(p=0.006).A shorter gastrointestinal tract recovery time was noticed in the short OT group(p=0.009).Prolonged OT was associated with a higher 90-day readmission rate on univariate and multivariate analyses(p<0.001,p=0.001,respectively).
基金supported by the National Natural Science Foundation of China(82374493).
文摘Objective:To investigate the clinical efficacy and safety of percutaneous kyphoplasty at different surgical timings in the treatment of osteoporotic vertebral compression fracture(OVCF)based on the theory of“dynamic-static integration”.Methods:Patients with OVCF who underwent percutaneous kyphoplasty in our hospital were selected and divided into Groups A,B,and C for those undergoing surgery within 7,7—21,and>21 days of fracture occurrence.The variations in the amount of bone cement injected,pre-and post-operative pain levels,functional activity,deformity correction of the injured vertebrae,bone cement leakage,and vertebral body height loss were compared among the three groups.Results:Regarding pain relief and functional activity,the postoperative Visual Analog Scale and Oswestry Disability Index scores of the three groups significantly improved.Furthermore,the deformities of the injured vertebrae in the three groups were significantly corrected,with Groups A and B exhibiting superior correction compared to Group C.Moreover,the bone cement leakage rates in groups A and C were higher than that in Group B.At the 3-month follow-up,the loss of vertebral height in Group C was significantly higher than those in groups A and B.Conclusion:Kyphoplasty is effective for OVCF treatment.Early surgery can effectively restore the vertebral height of the injured vertebra,reduce kyphosis,and reduce height loss of the injured vertebra after surgery;nevertheless,treatment within 1—3 weeks of the fracture can reduce the occurrence of bone cement leakage,making the surgery safer.Therefore,surgical treatment within 1—3 weeks of fracture is safer and can achieve satisfactory therapeutic effects.From the perspective of traditional Chinese medicine,PKP surgery can transform the fracture end from a micromotion state to a fixed state,which fully embodies the theory of“dynamic-static integration”.
基金The National Natural Science Foundation of China ( No.60872004, 60972026)the Important National Science and Technology Specific Projects (No. 2010ZX03006-002-01)the Research Fund of the National Mobile Communications Research Laboratory of Southeast University (No.2010A08)
文摘In order to improve network connectivity in clustered wireless sensor networks,a node cooperative algorithm based on virtual antenna arrays is proposed.All the nodes in the network are assumed to be clustered via Poisson Voronoi tessellation（PVT）.The activation of the node cooperative algorithm is determined by the cluster heads（CHs） according to communication links.When the cooperative algorithm is activated,the CH selects cooperative nodes（CNs） from its members to form a virtual antenna array.With the cooperation,nodes can extend the inter-cluster communication range to directly contact with further nodes after a coverage hole is detected,or compensate for channel gains while inter-cluster transmission fails due to deep channel fading.Simulation results show that the proposed algorithm achieves better network connectivity and energy efficiency.It can reduce outage probability,sustain network connectivity and maintain operations as long as possible,which prolongs network operation time.
文摘BACKGROUND Endoscopic submucosal dissection(ESD)is a treatment for early gastric cancer with the advantages of small invasion,fewer complications,and a low local recurrence rate.However,there is a high risk of complications such as bleeding and perforation,and the operation time is also longer.ESD operation time is closely related to bleeding and perforation.AIM To investigate the influencing factors associated with ESD operation time and postoperative delayed hemorrhage to provide a reference for early planning,early identification,and prevention of complications.METHODS We conducted a retrospective study based on the clinical data of 520 patients with early gastric cancer in the Second Affiliated Hospital of Hainan Medical University from January 2019 to December 2021.The baseline data,clinical features,and endoscopic and pathological characteristics of patients were collected.The multivariate linear regression model was used to investigate the influencing factors of ESD operation time.Logistic regression analysis was carried out to evaluate the influencing factors of postoperative delayed hemorrhage.RESULTS The multivariate analysis of ESD operation time showed that the maximum lesion diameter could affect 8.815%of ESD operation time when other influencing factors remained unchanged.The operation time increased by 3.766%or 10.247%if the lesion was mixed or concave.The operation time increased by 4.417%if combined with an ulcer or scar.The operation time increased by 3.692%if combined with perforation.If infiltrated into the submucosa,it increased by 2.536%.Multivariate analysis of delayed hemorrhage after ESD showed that the maximum diameter of the lesion,lesion morphology,and ESD operation time were independent influencing factors for delayed hemorrhage after ESD.Patients with lesion≥3.0 cm(OR=3.785,95%CI:1.165-4.277),lesion morphology-concave(OR=10.985,95%CI:2.133-35.381),and ESD operation time≥60 min(OR=2.958,95%CI:1.117-3.526)were prone to delayed hemorrhage after ESD.CONCLUSION If the maximum diameter of the lesion in patients with early gastric cancer is≥3.0 cm,and the shape of the lesion is concave,or accompanied by an ulcer or scar,combined with perforation,and infiltrates into the submucosa,the ESD operation will take a longer time.When the maximum diameter of the lesion is≥3.0 cm,the shape of the lesion is concave in patients and the operation time of ESD takes longer time,the risk of delayed hemorrhage after ESD is higher.
文摘Objective:While a rushed operation can omit essential procedures,prolonged operative time results in higher morbidity.Nevertheless,the optimal operative time range remains uncertain.This study aimed to estimate the ideal operative time range and evaluate its applicability in laparoscopic cancer surgery.Methods:A prospectively collected multicenter database of 397 patients who underwent laparoscopic distal gastrectomy were retrospectively reviewed.The ideal operative time range was statistically calculated by separately analyzing the operative time of uneventful surgeries.Finally,intraoperative and postoperative outcomes were compared among the shorter,ideal,and longer operative time groups.Results:The statistically calculated ideal operative time was 135.4-165.4 min.The longer operative time(LOT)group had a lower rate of uneventful,perfect surgery than the ideal or shorter operative time(IOT/SOT)group(2.8%vs.8.8%and 2.2%vs.13.4%,all P<0.05).Longer operative time increased bleeding,postoperative morbidities,and delayed diet and discharge(all P<0.05).Particularly,an uneventful,perfect surgery could not be achieved when the operative time exceeded 240 min.Regardless of ideal time range,SOT group achieved the highest percentage of uneventful surgery(13.4%),which was possible by surgeon's ability to retrieve a higher number of lymph nodes and perform≥150 gastrectomies annually.Conclusions:Operative time longer than the ideal time range(especially≥240 min)should be avoided.If the essential operative procedure were faithfully conducted without compromising oncological safety,an operative time shorter than the ideal range leaded to a better prognosis.Efforts to minimize operative time should be attempted with sufficient surgical experience.
文摘BACKGROUND Pancreatic adenocarcinoma is currently the fourth leading cause of cancer-related deaths in the United States.In patients with“borderline resectable”disease,current National Comprehensive Cancer Center guidelines recommend the use of neoadjuvant chemoradiation prior to a pancreaticoduodenectomy.Although neoadjuvant radiotherapy may improve negative margin resection rate,it is theorized that its administration increases operative times and complexity.AIM To investigate the association between neoadjuvant radiotherapy and 30-d morbidity and mortality outcomes among patients receiving a pancreaticoduodenectomy for pancreatic adenocarcinoma.METHODS Patients listed in the 2015-2019 National Surgery Quality Improvement Program data set,who received a pancreaticoduodenectomy for pancreatic adenocarcinoma,were divided into two groups based off neoadjuvant radiotherapy status.Multivariable regression was used to determine if there is a significant correlation between neoadjuvant radiotherapy,perioperative blood transfusion status,total operative time,and other perioperative outcomes.RESULTS Of the 11458 patients included in the study,1470(12.8%)underwent neoadjuvant radiotherapy.Patients who received neoadjuvant radiotherapy were significantly more likely to require a perioperative blood transfusion[adjusted odds ratio(aOR)=1.58,95%confidence interval(CI):1.37-1.82;P<0.001]and have longer surgeries(insulin receptor-related receptor=1.14,95%CI:1.11-1.16;P<0.001),while simultaneously having lower rates of organ space infections(aOR=0.80,95%CI:0.66-0.97;P=0.02)and pancreatic fistula formation(aOR=0.50,95%CI:0.40-0.63;P<0.001)compared to those who underwent surgery alone.CONCLUSION Neoadjuvant radiotherapy,while not associated with increased mortality,will impact the complexity of surgical resection in patients with pancreatic adenocarcinoma.
文摘BACKGROUND Timing of invasive intervention such as operative pancreatic debridement(OPD)in patients with acute necrotizing pancreatitis(ANP)is linked to the degree of encapsulation in necrotic collections and controlled inflammation.Additional markers of these processes might assist decision-making on the timing of surgical intervention.In our opinion,it is logical to search for such markers among routine laboratory parameters traditionally used in ANP patients,considering simplicity and cost-efficacy of routine laboratory methodologies.AIM To evaluate laboratory variables in ANP patients in the preoperative period for the purpose of their use in the timing of surgery.METHODS A retrospective analysis of routine laboratory parameters in 53 ANP patients undergoing OPD between 2017 and 2020 was performed.Dynamic changes of routine hematological and biochemical indices were examined in the preoperative period.Patients were divided into survivors and non-survivors.Survivors were divided into subgroups with short and long post-surgery length of stay(LOS)in hospital.Correlation analysis was used to evaluate association of laboratory variables with LOS.Logistic regression was used to assess risk factors for patient mortality.RESULTS Seven patients(15%)with severe acute pancreatitis(SAP)and 46 patients(85%)with moderately SAP(MSAP)were included in the study.Median age of participants was 43.2 years;33(62.3%)were male.Pancreatitis etiology included biliary(15%),alcohol(80%),and idiopathic/other(5%).Median time from diagnosis to OPD was≥4 wk.Median postoperative LOS was at the average of 53 d.Mortality was 19%.Progressive increase of platelet count in preoperative period was associated with shortened LOS.Increased aspartate aminotransferase and direct bilirubin(DB)levels the day before the OPD along with weak progressive decrease of DB in preoperative period were reliable predictors for ANP patient mortality.CONCLUSION Multifactorial analysis of dynamic changes of routine laboratory variables can be useful for a person-tailored timing of surgical intervention in ANP patients.
文摘Objective:To investigate the effect of body mass index(BMI)on the operation time and postoperative hospital stay for patients who underwent retroperitoneal laparoscopic decortication for a single simple renal cyst.Methods:A retrospective cohort study was conducted among 81 patients with single simple renal cyst who had undergone retroperitoneal laparoscopic cyst decortication from January 2017 to December 2019 in Wuxi Xishan People's Hospital.All patients were divided into three groups according to BMI:normal group(BMI<25 kg/m^(2),n=44),overweight group(BMI=25-30 kg/m^(2),n=21),and obese group(BMI>30 kg/m^(2),n=16).Multiple linear regression was conducted to investigate the correlation.Results:The three groups were comparable in terms of age,gender,maximum diameter of cyst,and cyst location.In the aspect of operation time,only the patients in obese group had longer duration when compared with those in the normal group(59.1±15.7 min vs.45.2±12.8 min,p=0.001).And the patients in the obese group had significantly longer hospital stay compared with those in the normal group(6.2±1.9 d vs.5.2±0.5 d,p=0.002)and overweight group(6.2±1.9 d vs.5.0±1.0d,p=0.001).In the analysis of multiple linear regression,it was found that operation time is significantly affected by BMI and location 2,with coefficients of 1.299 and -8.646 respectively.The influence of BMI was greater than location 2(0.335 vs.-0.289).For hospital stay,only BMI had an effect on it,with a coefficient of 0.110.Conclusion:BMI was a major factor that associated with longer operation time and hospital stay in patients with retroperitoneal laparoscopic renal cyst decortication.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11275024,61274024,and 61474123)the Youth Innovation Promotion Association,China(Grant No.2013105)the Ministry of Science and Technology of China(Grant Nos.2013YQ030595-3 and 2011AA120101)
文摘We characterized the dependence of the timing jitter of an InGaAs/InP single-photon avalanche diode on the excess bias voltage（V（ex）） when operated in 1-GHz sinusoidally gated mode.The single-photon avalanche diode was cooled to-30 degrees Celsius.When the V（ex） is too low（0.2 V-0.8 V） or too high（3 V-4.2 V）,the timing jitter is increased with the V（ex）,particularly at high V（ex）.While at middle V（ex）（1 V-2.8 V）,the timing jitter is reduced.Measurements of the timing jitter of the same avalanche diode with pulsed gating show that this effect is likely related to the increase of both the amplitude of the V（ex） and the width of the gate-on time.For the 1-GHz sinusoidally gated detector,the best jitter of 93 ps is achieved with a photon detection efficiency of 21.4%and a dark count rate of -2.08×10 -5 per gate at the V（ex） of 2.8 V.To evaluate the whole performance of the detector,we calculated the noise equivalent power（NEP） and the afterpulse probability（P（ap））.It is found that both NEP and P（ap） increase quickly when the V（ex） is above 2.8 V.At -2.8-V V（ex）,the NEP and P（ap） are -2.06×10-（16）W/Hz-（1/2） and 7.11%,respectively.Therefore,the detector should be operated with V（ex） of 2.8 V to exploit the fast time response,low NEP and low P（ap）.
基金supported by the Integrated Rail Transit Dispatch Control and Intermodal Transport Service Technology Project(Grant No.2022YFB4300500).
文摘The Balise Transmission Module(BTM)unit of the on-board train control system is a crucial component.Due to its unique installation position and complex environment,this unit has a higher fault rate within the on-board train control system.To conduct fault prediction for the BTM unit based on actual fault data,this study proposes a prediction method combining reliability statistics and machine learning,and achieves the fusion of prediction results from different dimensions through multi-method interactive validation.Firstly,a method for predicting equipment fault time targeting batch equipment is introduced.This method utilizes reliability statistics to construct a model of the remaining faultless operating time distribution considering uncertainty,thereby predicting the remaining faultless operating probability of the BTM unit.Secondly,considering the complexity of the BTM unit’s fault mechanism,the small sample size of fault cases,and the potential presence of multiple fault features in fault text records,an individual-oriented fault prediction method based on Bayesian-optimized Gradient Boosting Regression Tree(Bayes-GBRT)is proposed.This method achieves better prediction results compared to linear regression algorithms and random forest regression algorithms,with an average absolute error of only 0.224 years for predicting the fault time of this type of equipment.Finally,a multi-method interactive validation approach is proposed,enabling the fusion and validation of multi-dimensional results.The results indicate that the predicted fault time and the actual fault time conform to a log-normal distribution,and the parameter estimation results are basically consistent,verifying the accuracy and effectiveness of the prediction results.The above research findings can provide technical support for the maintenance and modification of BTM units,effectively reducing maintenance costs and ensuring the safe operation of high-speed railway,thus having practical engineering value for preventive maintenance.
文摘The key of artificial precipitation(snowfall) operation with the silver iodide generator which was set on the windward slope of mountain was the selection of updraft time.The updraft related to the entering cloud efficiency of effective nucleus.By contrasting and analyzing two times artificial snowfall operations,the timing of artificial precipitation(snowfall) operation with the silver iodide ground generator was discussed.By using the synoptic chart,satellite cloud chart,radar,physical quantity calculation and so on,the operation timing was determined.
文摘BACKGROUND Peripheral lung cancer poses a substantial harm to human health,and it is easy to become exacerbated,potentially threatening the life and safety of patients AIM To assess the value of virtual bronchoscopic navigation(VBN)combined with transbronchial ultrasound-guided sheath-guided(EBUS-GS)exploration in the diagnosis of peripheral lung cancer.METHODS A total of 236 patients with peripheral lung cancer(nodule diameter range,8-30 mm;diagnosed using high-resolution computed tomography)were selected from three centers between October 2018 and December 2019.Patients who underwent EBUS-GS exploration alone were included in a control group,and those who received VBN in combination with EBUS-GS exploration were included in an observation group.The diagnostic rate and total operating time of differentsubgroups of the two groups were compared,and the time needed to determine the lesion was recorded.RESULTS There were no significant differences in diagnosis rate or total operation time between the two groups(P>0.05),and the time needed to determine the lesion in the observation group was less than that of the control group(P<0.05).CONCLUSION The combined use of VBN and EBUS-GS exploration technology has little effect on the diagnosis rate and total operation time of peripheral lung cancer,but it significantly shortens the time needed to determine the lesion and is a valuable diagnostic method.
基金Supported by National Natural Science Foundation of China,No.U1713221.
文摘BACKGROUND In robot-assisted(RA)spine surgery,the relationship between the surgical outcome and the learning curve remains to be evaluated.AIM To analyze the learning curve of RA pedicle screw fixation(PSF)through fitting the operation time curve based on the cumulative summation method.METHODS RA PSFs that were initially completed by two surgeons at the Beijing Jishuitan Hospital from July 2016 to March 2019 were analyzed retrospectively.Based on the cumulative sum of the operation time,the learning curves of the two surgeons were drawn and fit to polynomial curves.The learning curve was divided into the early and late stages according to the shape of the fitted curve.The operation time and screw accuracy were compared between the stages.RESULTS The turning point of the learning curves from Surgeons A and B appeared in the 18th and 17th cases,respectively.The operation time[150(128,188)min vs 120(105,150)min,P=0.002]and the screw accuracy(87.50%vs 96.30%,P=0.026)of RA surgeries performed by Surgeon A were significantly improved after he completed 18 cases.In the case of Surgeon B,the operation time(177.35±28.18 min vs 150.00±34.64 min,P=0.024)was significantly reduced,and the screw accuracy(91.18%vs 96.15%,P=0.475)was slightly improved after the surgeon completed 17 RA surgeries.CONCLUSION After completing 17 to 18 cases of RA PSFs,surgeons can pass the learning phase of RA technology.The operation time is reduced afterward,and the screw accuracy shows a trend of improvement.
基金This project was financially supported by the National Natural Science Foundations of China(Grant No.5967900559839330)
文摘The generation of low frequency waves by a single or double wave groups incident upon two Plane beaches with the slope of 1/40 and 1/100 is investigated experimentally and numerically. A new type of wave maker signal is used to generate the groups, allowing the bound long wave (set-down) to be included in the group. The experiments show that the low frequency wave is generated during breaking and propagation to the shoreline of the wave group. This process of generation and propagation of low frequency waves is simulated numerically by solving the short-wave averaged mass and momentum conservation equations. The computed and measured results are in good agreement. The mechanism of generation of low frequency waves in the surf zone is examined and discussed.
基金Project supported partly by the Open Research Program in State Key Laboratory of Millimeter Waves of China(Grant No.K200802)partly by the National Natural Science Foundation of China(Grant No.60971122)
文摘The transmission coefficients of electromagnetic （EM） waves due to a superconductor-dielectric superlattice are numerically calculated. Shift operator finite difference time domain （SO-FDTD） method is used in the analysis. By using the SO-FDTD method, the transmission spectrum is obtained and its characteristics are investigated for different thicknesses of superconductor layers and dielectric layers, from which a stop band starting from zero frequency can be apparently observed. The relation between this low-frequency stop band and relative temperature, and also the London penetration depth at a superconductor temperature of zero degree are discussed, separately. The low-frequency stop band properties of superconductor-dielectric superlattice thus are well disclosed.
文摘Based on the general theory of time-dependent quantum transformation, we use the 'time evolutionoperator' method to solve the single-mode time-dependent oscillator.
