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Failure transition of shear-to-dilation band of rock salt under triaxial stresses 被引量:1
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作者 Jianfeng Liu Xiaosong Qiu +3 位作者 Jianxiong Yang Chao Liang Jingjing Dai Yu Bian 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第1期56-64,共9页
Great potential of underground gas/energy storage in salt caverns seems to be a promising solution to support renewable energy.In the underground storage method,the operating cycle unfortunately may reach up to daily ... Great potential of underground gas/energy storage in salt caverns seems to be a promising solution to support renewable energy.In the underground storage method,the operating cycle unfortunately may reach up to daily or even hourly,which generates complicated pressures on the salt cavern.Furthermore,the mechanical behavior of rock salt may change and present distinct failure characteristics under different stress states,which affects the performance of salt cavern during the time period of full service.To reproduce a similar loading condition on the cavern surrounding rock mass,the cyclic triaxial loading/unloading tests are performed on the rock salt to explore the mechanical transition behavior and failure characteristics under different confinement.Experimental results show that the rock salt samples pre-sent a diffused shear failure band with significant bulges at certain locations in low confining pressure conditions(e.g.5 MPa,10 MPa and 15 MPa),which is closely related to crystal misorientation and grain boundary sliding.Under the elevated confinement(e.g.20 MPa,30 MPa and 40 MPa),the dilation band dominates the failure mechanism,where the large-size halite crystals are crushed to be smaller size and new pores are developing.The failure transition mechanism revealed in the paper provides additional insight into the mechanical performance of salt caverns influenced by complicated stress states. 展开更多
关键词 Rock salt Cyclic mechanical loading Shear band dilation band Underground gas storage(UGS)
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Long-term outcomes of urethral balloon dilation for anterior urethral stricture: A prospective cohort study
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作者 Ahmed M.Abdel Gawad Abhijit Patil +3 位作者 Abhishek Singh Arvind P.Ganpule Ravindra B.Sabnis Mahesh R.Desai 《Asian Journal of Urology》 CSCD 2024年第3期480-485,共6页
Objective:To prospectively follow up a cohort of anterior urethral stricture disease patients managed with balloon dilation(BD)for 3 years to evaluate the long-term outcomes and to study factors that contribute to rec... Objective:To prospectively follow up a cohort of anterior urethral stricture disease patients managed with balloon dilation(BD)for 3 years to evaluate the long-term outcomes and to study factors that contribute to recurrence.Methods:This study included men who had urethral BD for significant anterior urethral stricture disease between January 2017 and March 2019.Data about the patient age,stricture characteristics,and recurrence date were recorded,along with information on postoperative indwelling catheter use and operative complications.Furthermore,information about the self-calibration procedure was collected and where available,free flow(FF)measurements during the follow-up period were recorded and analyzed.Success was defined as a lack of symptoms and acceptable FF rates(maximum flow rate>12 mL/s).Results:The final analysis was conducted on 187 patients.The mean follow-up period was 37 months.The long-term overall success rate at the end of our study was 66.8%.Our recurrence rate was 7.4%at 12 months,24.7%at 24 months,and reached 33.2%at the end of our study.The time to recurrence ranged from 91 days to 1635 days,with a mean of 670 days.The stricture-free survival was significantly shorter with lengthy peno-bulbar(p=0.031)and multiple strictures(p=0.015),and in the group of patients who were not committed to self-calibration protocol(p<0.011).However,post-procedural self-calibration was the most important factor that may have decreased the incidence of recurrence(odds ratioZ5.85).Adjuvant self-calibration after BD not only reduced the recurrence rate from 85.4%in the non-self-calibration group to 15.1%in the self-calibration one(p<0.001),but also improved the overall stricture-free survival and FF parameters. 展开更多
关键词 Balloon dilation Internal urethrotomy RECURRENCE SELF-CALIBRATION Urethral stricture
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Dilation,discrimination and Uhlmann's theorem of link products of quantum channels
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作者 雷强 操刘桁 +1 位作者 Asutosh Kumar 武俊德 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第3期201-206,共6页
We establish the Stinespring dilation theorem of the link product of quantum channels in two different ways,discuss the discrimination of quantum channels,and show that the distinguishability can be improved by self-l... We establish the Stinespring dilation theorem of the link product of quantum channels in two different ways,discuss the discrimination of quantum channels,and show that the distinguishability can be improved by self-linking each quantum channel n times as n grows.We also find that the maximum value of Uhlmann's theorem can be achieved for diagonal channels. 展开更多
关键词 quantum channels link products Stinespring dilation theorem Uhlmann's theorem
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Effect of endoscopic sphincterotomy and endoscopic papillary balloon dilation endoscopic retrograde cholangiopancreatographies on the sphincter of Oddi
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作者 Kai Fu Ying-Ying Yang +3 位作者 Hui Chen Guang-Xin Zhang Yan Wang Zhi Yin 《World Journal of Gastrointestinal Surgery》 SCIE 2024年第6期1726-1733,共8页
BACKGROUND Endoscopic retrograde cholangiopancreatography(ERCP),with its clinical ad-vantages of less trauma and faster recovery,has become the primary treatment for choledocholithiasis.AIM To investigate the effects ... BACKGROUND Endoscopic retrograde cholangiopancreatography(ERCP),with its clinical ad-vantages of less trauma and faster recovery,has become the primary treatment for choledocholithiasis.AIM To investigate the effects of different ERCP procedures on the sphincter of Oddi.METHODS The clinical data of 91 patients who underwent ERCP at Yixing Hospital of Traditional Chinese Medicine between February 2018 and February 2021 were analyzed retrospectively.The patients were divided into endoscopic sphinc-terotomy(EST,n=24)and endoscopic papillary balloon dilation(EPBD,n=67)groups.The duration of operation,pancreatic development,pancreatic sphinc-terotomy,intubation difficulties,stone recurrence,and incidence of reflux cho-langitis and cholecystitis were statistically analyzed in patients with a history of choledocholithiasis,pancreatitis,and Oddi sphincter dysfunction in the EST and EPBD groups.RESULTS Differences in hypertension,diabetes,increased bilirubin,small diameter of the common bile duct,or ampullary diverticulum between the two groups were not significant.Statistically significant differences were observed between the two groups concerning sex and age(<60 years).Patients with a history of choledocholithiasis,pancreatitis,and Oddi sphincter dysfunction were higher in the EST group than in the EPBD group.The number of cases of pancreatic development,pancreatic duct sphincterotomy,and difficult intubation were higher in the EST group than in the EPBD group.The number of Oddi’s sphincter manometries,ERCP surgical outcomes,and guidewires entering the pancreatic duct several times in EST group were lower than those in the EPBD group.The numbers of stone recurrences,reflux cholangitis,and cholecystitis were higher in the EST group than in the EPBD group.CONCLUSION In summary,common bile duct stones,pancreatitis history,and multiple guided wire introductions into the pancreatic duct are independent risk factors for EST and EPBD.Based on this evidence,this study can provide actionable insights for clinicians and researchers. 展开更多
关键词 ODDI CHOLANGIOPANCREATOGRAPHY Endoscopic retrograde Risk factors Endoscopic sphincterotomy Endoscopic papillary balloon dilation
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Clinical efficacy of laparoscopic cholecystectomy combined with endoscopic papillary balloon dilation in treatment of gallbladder stones with common bile duct stones: A retrospective study
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作者 Hong-Dan Liu Qi Zhang +1 位作者 Wen-Si Xu Shuang Jin 《World Journal of Gastrointestinal Surgery》 SCIE 2024年第6期1700-1708,共9页
BACKGROUND The incidence of cholelithiasis has been on the rise in recent years,but the choice of procedure is controversial.AIM To investigate the efficacy of laparoscopic cholecystectomy(LC)combined with endoscopic ... BACKGROUND The incidence of cholelithiasis has been on the rise in recent years,but the choice of procedure is controversial.AIM To investigate the efficacy of laparoscopic cholecystectomy(LC)combined with endoscopic papillary balloon dilation(EPBD)in patients with gallbladder stones(GS)with common bile duct stones(CBDS).METHODS The clinical data of 102 patients with GS combined with CBDS were selected for retrospective analysis and divided into either an LC+EPBD group(n=50)or an LC+endoscopic sphincterotomy(EST)group(n=52)according to surgical methods.Surgery-related indexes,postoperative recovery,postoperative complications,and expression levels of inflammatory response indexes were compared between the two groups.RESULTS Total surgical time,stone free rate,rate of conversion to laparotomy,and successful stone extraction rate did not differ significantly between the LC+EPBD group and LC+EST group.Intraoperative hemorrhage,time to ambulation,and length of hospitalization in the LC+EPBD group were lower than those of the LC+EST group(P<0.05).The rate of total complications of the two groups was 9.80%and 17.65%,respectively,and the difference was not statistically significant.No serious complications occurred in either group.At 48 h postoperatively,the expression levels of interleukin-6,tumor necrosis factor-α,high-sensitivity Creactive protein,and procalcitonin were lower in the LC+EPBD group than in the LC+EST group(P<0.05).At 3 d postoperatively,the expression levels of aspartate transaminase,alanine transaminase,and total bilirubin were lower in the LC+EPBD group than in the LC+EST group(P<0.05).CONCLUSION LC combined with EPBD and LC combined with EST are both effective procedures for the treatment of GS with CBDS,in which LC combined with EPBD is beneficial to shorten the patient’s hospitalization time,reduce the magnitude of elevated inflammatory response indexes,and promote postoperative recovery. 展开更多
关键词 Gallbladder stone Common bile duct stone Endoscopic papillary balloon dilation Laparoscopic cholecystectomy Endoscopic sphincterotomy
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Balloon dilation of congenital perforated duodenal web in newborns: Evaluation of short and long-term results
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作者 Kirill Marakhouski Elena Malyshka +5 位作者 Katsiaryna Nikalayeva Larysa Valiok Aleh Pataleta Kiryl Sanfirau Aliaksandr Svirsky Vasily Averin 《World Journal of Gastrointestinal Endoscopy》 2024年第6期343-349,共7页
BACKGROUND Incomplete congenital duodenal obstruction(ICDO)is caused by a congenitally perforated duodenal web(CPDW).Currently,only six cases of balloon dilatation of the PDW in newborns have been described.AIM To pre... BACKGROUND Incomplete congenital duodenal obstruction(ICDO)is caused by a congenitally perforated duodenal web(CPDW).Currently,only six cases of balloon dilatation of the PDW in newborns have been described.AIM To present our experience of balloon dilatation of a perforated duodenal memb-rane in newborns with ICDO.METHODS Five newborns who underwent balloon dilatation of the CPDW along a prein-stalled guidewire between 2021 and 2023 were included.Nineteen newborns diagnosed with ICDO who underwent laparotomy were included in the control group.RESULTS In all cases,good anatomical and clinical results were obtained.In three cases,a follow-up study was conducted after 1 year.The average time to start enteral feeding per os was significantly earlier in the study group(4.4 d)than in the laparotomic group(21.2 days;P<0.0001).The time spent by patients in the intensive care unit and hospital after balloon dilatation was also significantly shorter.We determined the selection criteria for possible and effective CPDW balloon dilatation in newborns as follows:(1)Presence of dynamic radiographic signs of the passage of a radiopaque substance beyond the zone of narrowing or radiographic signs of pneumatisation of the duodenum and small bowel distal to the web;(2)presence of endoscopic signs of CPDW;(3)successful cannulation with a guidewire performed parallel to the endoscope,with holes in the congenital duodenal web;and(4)successful positioning of the balloon performed along a freestanding guidewire on the web.CONCLUSION Strictly following selection criteria for newborns with ICDO caused by CPDW ensures that endoscopic balloon dilatation using a pre-installed guidewire is safe and effective and shows good 1-year follow-up results. 展开更多
关键词 NEWBORNS Congenital duodenal obstruction Perforated duodenal membrane ENDOSCOPY Balloon dilation
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The Space Dilation: Analyzing Progressive Speed Reduction and Its Relativistic Parallels
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作者 Kreshnik Feka 《Journal of Applied Mathematics and Physics》 2024年第8期2990-3005,共16页
This paper presents a conceptual exploration that draws an intriguing parallelbetween a hypothetical travel scenario and the principles of special relativity. The scenario involves a traveler who reduces their speed b... This paper presents a conceptual exploration that draws an intriguing parallelbetween a hypothetical travel scenario and the principles of special relativity. The scenario involves a traveler who reduces their speed by an amount proportional to the distance traveled. Despite initially traveling at a high speed towards a given destination, the continual reduction in speed results in an asymptotic approach to the goal, analogous to the unattainable speed of light in relativity. Mathematically, the scenario is expressed through the Harmonic Series, demonstrating that the total travel time increases without bound, making the destination theoretically unreachable within a finite timeframe. This exploration mirrors the relativistic velocity addition and time dilation effects, providing a compelling analogy for understanding asymptotic limits. By highlighting the profound implications of diminishing returns and unattainable goals, this paper aims to stimulate further discussion and exploration of these fascinating parallels. 展开更多
关键词 Asymptotic Limits Special Relativity Harmonic Series Time dilation Diminishing Returns
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Time Dilation Cosmology 2
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作者 Joseph H. (Cass) Forrington 《Journal of Modern Physics》 2024年第4期448-461,共14页
This paper is a further elaboration of the author’s Time Dilation Cosmology (TDC) holographic model that ties gravitation and celestial mechanics and kinematics directly to time dilation, resolving all the major conu... This paper is a further elaboration of the author’s Time Dilation Cosmology (TDC) holographic model that ties gravitation and celestial mechanics and kinematics directly to time dilation, resolving all the major conundrums in astrophysics, and ties astrophysics directly to quantum physics. It begins with a brief summary of the TDC model and contains the new derivation for the time dilation version of the formula for summing relativistic velocities, Einstein’s gravitational constant and the time dilation versions for the Lorentz factor and the Euclidean norm of the 3d velocity vector, the two of which can then be used in the Four-velocity formula. It is demonstrated how orbital curvature is manifested as the resultant of two time dilation-manifested velocities. It also explains why an interferometer cannot distinguish free fall from zero gravity and further elaborates on the author’s previous explanations of how spiral galaxies are formed, and contains mathematical proof that Black Holes are actually Magnetospheric Eternally Collapsing Objects (MECOs) that are massless spacetime vortices. 展开更多
关键词 GRAVITATION Time Time dilation Celestial Mechanics ISM: Kinematics and Dynamics Cosmology: Theory Galaxies: Evolution
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Long-term outcomes of endoscopic papillary large-balloon dilation(12-15 mm)with or without limited sphincterotomy for removal of bile duct stones 被引量:1
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作者 Tao Li Li-Xiao Hao +6 位作者 Chan Lv Xing-Jia Li Xiao-Dan Ji Meng Chen Chang Liu Li-Ke Bie Biao Gong 《Hepatobiliary & Pancreatic Diseases International》 SCIE CAS CSCD 2023年第4期392-398,共7页
Background:Limited endoscopic sphincterotomy with large balloon dilation(ES-LBD)and endoscopic papillary large-balloon dilation(EPLBD)have been proven safe and effective for removal of bile duct stones.However,the lon... Background:Limited endoscopic sphincterotomy with large balloon dilation(ES-LBD)and endoscopic papillary large-balloon dilation(EPLBD)have been proven safe and effective for removal of bile duct stones.However,the long-term outcomes are not clear.The aim of this study was to assess the long-term outcomes of EPLBD(12-15 mm)with or without limited sphincterotomy for removal of common bile duct(CBD)stones.Methods:Patients with EPLBD or ES-LBD referred for the removal of bile-duct stones between June 2008 and August 2020 were retrospectively reviewed.Complete stone clearance,endoscopic retrograde cholangiopancreatography(ERCP)-related adverse events,and late biliary complications during long-term follow-up were analyzed.Results:Basic patient characteristics were not significantly different between the groups that underwent EPLBD(n=168)and ES-LBD(n=57).EPLBD compared with ES-LBD resulted in similar outcomes in terms of overall successful stone removal(99.4%vs.100%,P=1.00)and ERCP-related adverse events(7.7%vs.5.3%,P=0.77).The mean duration of the follow-up were 113.6 months and 106.7 months for patients with EPLBD and ES-LBD,respectively(P=0.13).There was no significant difference between EPLBD and ES-LBD in the incidence of stone recurrence[20(11.9%)vs.9(15.8%);P=0.49].Multivariate analysis showed that a diameter of CBD≥15 mm(OR=3.001;95%CI:1.357-6.640;P=0.007)was an independent risk factor for stone recurrence.Conclusions:The application of a large balloon(12-15 mm)via EPLBD is an effective and safe alternative to ES-LBD for extraction of large CBD stones.Endoscopic sphincterotomy prior to EPLBD may be unnec-essary.A diameter of CBD≥15 mm is a risk factor of stone recurrence. 展开更多
关键词 Endoscopic papillary large-balloon dilation Endoscopic sphincterotomy Bile duct stone
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Advanced Face Mask Detection Model Using Hybrid Dilation Convolution Based Method 被引量:1
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作者 Shaohan Wang Xiangyu Wang Xin Guo 《Journal of Software Engineering and Applications》 2023年第1期1-19,共19页
A face-mask object detection model incorporating hybrid dilation convolutional network termed ResNet Hybrid-dilation-convolution Face-mask-detector (RHF) is proposed in this paper. Furthermore, a lightweight face-mask... A face-mask object detection model incorporating hybrid dilation convolutional network termed ResNet Hybrid-dilation-convolution Face-mask-detector (RHF) is proposed in this paper. Furthermore, a lightweight face-mask dataset named Light Masked Face Dataset (LMFD) and a medium-sized face-mask dataset named Masked Face Dataset (MFD) with data augmentation methods applied is also constructed in this paper. The hybrid dilation convolutional network is able to expand the perception of the convolutional kernel without concern about the discontinuity of image information during the convolution process. For the given two datasets being constructed above, the trained models are significantly optimized in terms of detection performance, training time, and other related metrics. By using the MFD dataset of 55,905 images, the RHF model requires roughly 10 hours less training time compared to ResNet50 with better detection results with mAP of 93.45%. 展开更多
关键词 Face Mask Detection Object Detection Hybrid dilation Convolution Computer Vision
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On Unitary N-Dilations for Tuples of Circulant Contractions and von Neumann’s Inequality
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作者 Joachim Moussounda Mouanda Edwige Josette Maleka Koubemba Djagwa Dehainsala 《American Journal of Computational Mathematics》 2023年第4期594-606,共13页
We introduce the spectral mapping factorization of tuples of circulant matrices and its matrix version. We prove that every tuple of circulant contractions has a unitary N-dilation. We show that von Neumann’s inequal... We introduce the spectral mapping factorization of tuples of circulant matrices and its matrix version. We prove that every tuple of circulant contractions has a unitary N-dilation. We show that von Neumann’s inequality holds for tuples of circulant contractions. We construct completely contractive homomorphisms over the algebra of complex polynomials defined on . 展开更多
关键词 dilationS POLYNOMIALS Matrices
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经鼓室口咽鼓管球囊扩张术的疗效及咽鼓管功能的影响
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作者 谢先荣 付亚峰 刘伟清 《中国耳鼻咽喉头颈外科》 CSCD 2024年第2期122-124,共3页
目的探讨经鼓室口咽鼓管球囊扩张(balloon dilatation Eustachian tuboplasty,BET)联合腺样体消融术对慢性分泌性中耳炎(chronic secretory otitis media,CSOM)患儿的疗效及咽鼓管功能的影响。方法选取2020年6月~2022年12月间在中山市... 目的探讨经鼓室口咽鼓管球囊扩张(balloon dilatation Eustachian tuboplasty,BET)联合腺样体消融术对慢性分泌性中耳炎(chronic secretory otitis media,CSOM)患儿的疗效及咽鼓管功能的影响。方法选取2020年6月~2022年12月间在中山市小榄人民医院就诊的CSOM患儿82例作为研究对象,采用随机数字表法分为对照组和观察组,每组41例。对照组接受腺样体消融术+鼓膜切开置管术治疗,观察组接受腺样体消融术+鼓膜切开置管术+BET术。比较两组手术相关指标及住院时间、临床症状、咽鼓管功能、临床疗效及随访6个月并发症及复发情况。结果两组术中出血量比较,差异无统计学意义(P>0.05),与对照组相比,观察组手术时间更长,住院时间更短(P<0.05)。与对照组相比,观察组中耳积液消失时间、耳鸣消失时间、鼓膜愈合时间、听力恢复时间均更短(P<0.05)。与治疗前相比,治疗后两组咽鼓管评分(Eustachian tube score,ETS)升高、咽鼓管功能障碍评分量表(Eustachian tube dysfunction questionnaire-7,ETDQ-7)评分降低(P<0.05),观察组ETS评分高于对照组,ETDQ-7评分则低于对照组(P<0.05)。观察组临床总有效率高于对照组,差异具有统计学意义(P<0.05)。两组并发症发生率比较,差异无统计学意义(14.63%vs.9.76%,P>0.05),与对照组相比,观察组复发率更低,差异具有统计学意义(21.95%vs.2.44%,P<0.05)。结论经鼓室口BET联合腺样体消融术有助于提高CSOM患儿的临床疗效,改善咽鼓管功能,促进术后恢复,减少复发率,且并发症发生率低。 展开更多
关键词 伴渗出液中耳炎(Otitis Media with Effusion) 咽鼓管(Eustachian Tube) 扩张术(Dilatation) 腺样体切除术(Adenoidectomy) 咽鼓管球囊扩张术(balloon dilatation Eustachian tuboplasty) 咽鼓管鼓室口(tympanic opening of Eustachian tube)
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Response letter to “Acute cholangitis: Does malignant biliary obstruction vs choledocholithiasis etiology change the outcomes?” with imaging aspects 被引量:1
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作者 Sonay Aydin Baris Irgul 《World Journal of Clinical Cases》 SCIE 2024年第5期1029-1032,共4页
Radiological imaging findings may contribute to the differentiation of malignant biliary obstruction from choledocholithiasis in the etiology of acute cholangitis.
关键词 Malignant biliary obstruction CHOLEDOCHOLITHIASIS Acute cholangitis Dilated bile ducts Magnetic resonance cholangiopancreatography Endoscopic retrograde cholangiopancreatography
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超声辅助与纤维支气管镜辅助经皮扩张气管切开术的对比研究
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作者 郭龙飞 张冬泉 +1 位作者 王全红 李浩 《中国耳鼻咽喉头颈外科》 CSCD 2024年第1期63-65,共3页
目的探讨超声辅助经皮扩张气管切开术的应用价值。方法回顾性分析2020年12月~2022年12月在甘肃省人民医院重症医学科行经皮扩张气管切开术患者56例,均经口气管插管后呼吸机辅助呼吸,根据不同的辅助方式分为超声辅助(超声组)31例和纤维... 目的探讨超声辅助经皮扩张气管切开术的应用价值。方法回顾性分析2020年12月~2022年12月在甘肃省人民医院重症医学科行经皮扩张气管切开术患者56例,均经口气管插管后呼吸机辅助呼吸,根据不同的辅助方式分为超声辅助(超声组)31例和纤维支气管镜辅助(纤维支气管镜组)25例。结果与纤维支气管镜组比较,超声组术中氧合指数(PaO_(2)/FiO_(2))增高[(157.3±19.2)mmHg vs.(145.4±22.8)mmHg,t=2.117,P=0.039],分钟通气(MV)量增高[(7.3±0.8)L/min vs.(6.1±0.7)L/min,t=5.278,P<0.001],动脉血二氧化碳分压(PCO_(2))降低[(39.1±4.8)mmHgvs.(44.3±5.6)mmHg,t=-3.709,P<0.001],术后出血例数减少[0例vs.4例,χ^(2)=5.246,P=0.022]。结论超声组较纤维支气管镜组行经皮扩张气管切开术手术并发症少,安全性高。 展开更多
关键词 对比研究(Comparative Study) 超声检查(Ultrasonography) 经皮扩张气管切开术(percutaneous dilatational tracheotomy)
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Mechanical response and dilatancy characteristics of deep marble under different stress paths:A sight from energy dissipation
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作者 LIU Xiao-hui HAO Qi-jun +2 位作者 ZHENG Yu ZHANG Zhao-peng XUE Yang 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第6期2070-2086,共17页
Dilatancy is a fundamental volumetric growth behavior observed during loading and serves as a key index to comprehending the intricate nonlinear behavior and constitutive equation structure of rock.This study focuses ... Dilatancy is a fundamental volumetric growth behavior observed during loading and serves as a key index to comprehending the intricate nonlinear behavior and constitutive equation structure of rock.This study focuses on Jinping marble obtained from the Jinping Underground Laboratory in China at a depth of 2400 m.Various uniaxial and triaxial tests at different strain rates,along with constant confining pressure tests and reduced confining pressure tests under different confining pressures were conducted to analyze the mechanical response and dilatancy characteristics of the marble under four stress paths.Subsequently,a new empirical dilatancy coefficient is proposed based on the energy dissipation method.The results show that brittle failure characteristics of marble under uniaxial compression are more obvious with the strain rate increasing,and plastic failure characteristics of marble under triaxial compression are gradually strengthened.Furthermore,compared to the constant confining pressure,the volume expansion is relatively lower under unloading condition.The energy dissipation is closely linked to the process of dilatancy,with a rapid increase of dissipated energy coinciding with the beginning of dilatancy.A new empirical dilatancy coefficient is defined according to the change trend of energy dissipation rate curve,of which change trend is consistent with the actual dilatancy response in marble under different stress paths.The existing empirical and theoretical dilatancy models are analyzed,which shows that the empirical dilatancy coefficient based on the energy background is more universal. 展开更多
关键词 deep marble stress paths DILATANCY energy dissipation empirical dilatancy coefficient
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Preliminary exploration of animal models of congenital choledochal cysts
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作者 Shu-Hao Zhang Yue-Bin Zhang +7 位作者 Duo-Te Cai Tao Pan Ken Chen Yi Jin Wen-Juan Luo Zong-Wei Huang Qing-Jiang Chen Zhi-Gang Gao 《World Journal of Gastroenterology》 SCIE CAS 2024年第10期1420-1430,共11页
BACKGROUND Various animal models have been used to explore the pathogenesis of choledochal cysts(CCs),but with little convincing results.Current surgical techniques can achieve satisfactory outcomes for treatment of C... BACKGROUND Various animal models have been used to explore the pathogenesis of choledochal cysts(CCs),but with little convincing results.Current surgical techniques can achieve satisfactory outcomes for treatment of CCs.Consequently,recent studies have focused more on clinical issues rather than basic research.Therefore,we need appropriate animal models to further basic research.AIM To establish an appropriate animal model that may contribute to the investigation of the pathogenesis of CCs.METHODS Eighty-four specific pathogen-free female Sprague-Dawley rats were randomly allocated to a surgical group,sham surgical group,or control group.A rat model of CC was established by partial ligation of the bile duct.The reliability of the model was confirmed by measurements of serum biochemical indices,morpho-logy of common bile ducts of the rats as well as molecular biology experiments in rat and human tissues.RESULTS Dilation classified as mild(diameter,≥1 mm to<3 mm),moderate(≥3 mm to<10 mm),and severe(≥10 mm)was observed in 17,17,and 2 rats in the surgical group,respectively,while no dilation was observed in the control and sham surgical groups.Serum levels of alanine aminotransferase,aspartate aminotrans-ferase,total bilirubin,direct bilirubin,and total bile acids were significantly elevated in the surgical group as compared to the control group 7 d after surgery,while direct bilirubin,total bilirubin,and gamma-glutamyltransferase were further increased 14 d after surgery.Most of the biochemical indices gradually decreased to normal ranges 28 d after surgery.The protein expression trend of signal transducer and activator of transcription 3 in rat model was consistent with the human CC tissues.CONCLUSION The model of partial ligation of the bile duct of juvenile rats could morphologically simulate the cystic or fusiform CC,which may contribute to investigating the pathogenesis of CC. 展开更多
关键词 Choledochal cyst Animal model Partial ligation Cystic and fusiform dilation Juvenile rats
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Numerical modelling of post-failure behaviors of coal specimens
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作者 Ajeet Yadav Bhaskara Behera +1 位作者 Gauri Shankar Prasad Singh Sanjay Kumar Sharma 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第2期514-531,共18页
A modelling approach consisting of best-fit relations to estimate the post-yield strength parameters is presented for simulating post-peak behavior beyond the point of residual strength of coal pillars having differen... A modelling approach consisting of best-fit relations to estimate the post-yield strength parameters is presented for simulating post-peak behavior beyond the point of residual strength of coal pillars having different w/h ratios.The model was developed based on back-analysis of the complete stress-strain behavior of specimens belonging to six different Indian coal seams with different w/h ratios of 0.5 e13.5.It was found that the simultaneous degradation of the cohesion and friction angle of the Mohr-Coulomb rock material characterizes the post-peak strength behavior of the rock.The resulting expressions are simplistic as they require parameters that can be easily determined using uniaxial and triaxial compression results.Eventually,the developed model was validated by simulating the triaxial tests of coal specimens with different sizes under varying confining stresses and comparing its findings with the published test results.The study showed that its implementation in the numerical model could reproduce laboratory-observed mechanical response,deformation behavior,and failure mechanism very closely. 展开更多
关键词 Strain softening DILATANCY INTERFACE Shape effect Residual strength
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Convolution-Transformer for Image Feature Extraction
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作者 Lirong Yin Lei Wang +10 位作者 Siyu Lu Ruiyang Wang Youshuai Yang Bo Yang Shan Liu Ahmed AlSanad Salman A.AlQahtani Zhengtong Yin Xiaolu Li Xiaobing Chen Wenfeng Zheng 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第10期87-106,共20页
This study addresses the limitations of Transformer models in image feature extraction,particularly their lack of inductive bias for visual structures.Compared to Convolutional Neural Networks(CNNs),the Transformers a... This study addresses the limitations of Transformer models in image feature extraction,particularly their lack of inductive bias for visual structures.Compared to Convolutional Neural Networks(CNNs),the Transformers are more sensitive to different hyperparameters of optimizers,which leads to a lack of stability and slow convergence.To tackle these challenges,we propose the Convolution-based Efficient Transformer Image Feature Extraction Network(CEFormer)as an enhancement of the Transformer architecture.Our model incorporates E-Attention,depthwise separable convolution,and dilated convolution to introduce crucial inductive biases,such as translation invariance,locality,and scale invariance,into the Transformer framework.Additionally,we implement a lightweight convolution module to process the input images,resulting in faster convergence and improved stability.This results in an efficient convolution combined Transformer image feature extraction network.Experimental results on the ImageNet1k Top-1 dataset demonstrate that the proposed network achieves better accuracy while maintaining high computational speed.It achieves up to 85.0%accuracy across various model sizes on image classification,outperforming various baseline models.When integrated into the Mask Region-ConvolutionalNeuralNetwork(R-CNN)framework as a backbone network,CEFormer outperforms other models and achieves the highest mean Average Precision(mAP)scores.This research presents a significant advancement in Transformer-based image feature extraction,balancing performance and computational efficiency. 展开更多
关键词 TRANSFORMER E-Attention depth convolution dilated convolution CEFormer
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TSCND:Temporal Subsequence-Based Convolutional Network with Difference for Time Series Forecasting
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作者 Haoran Huang Weiting Chen Zheming Fan 《Computers, Materials & Continua》 SCIE EI 2024年第3期3665-3681,共17页
Time series forecasting plays an important role in various fields, such as energy, finance, transport, and weather. Temporal convolutional networks (TCNs) based on dilated causal convolution have been widely used in t... Time series forecasting plays an important role in various fields, such as energy, finance, transport, and weather. Temporal convolutional networks (TCNs) based on dilated causal convolution have been widely used in time series forecasting. However, two problems weaken the performance of TCNs. One is that in dilated casual convolution, causal convolution leads to the receptive fields of outputs being concentrated in the earlier part of the input sequence, whereas the recent input information will be severely lost. The other is that the distribution shift problem in time series has not been adequately solved. To address the first problem, we propose a subsequence-based dilated convolution method (SDC). By using multiple convolutional filters to convolve elements of neighboring subsequences, the method extracts temporal features from a growing receptive field via a growing subsequence rather than a single element. Ultimately, the receptive field of each output element can cover the whole input sequence. To address the second problem, we propose a difference and compensation method (DCM). The method reduces the discrepancies between and within the input sequences by difference operations and then compensates the outputs for the information lost due to difference operations. Based on SDC and DCM, we further construct a temporal subsequence-based convolutional network with difference (TSCND) for time series forecasting. The experimental results show that TSCND can reduce prediction mean squared error by 7.3% and save runtime, compared with state-of-the-art models and vanilla TCN. 展开更多
关键词 DIFFERENCE data prediction time series temporal convolutional network dilated convolution
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An improved deep dilated convolutional neural network for seismic facies interpretation
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作者 Na-Xia Yang Guo-Fa Li +2 位作者 Ting-Hui Li Dong-Feng Zhao Wei-Wei Gu 《Petroleum Science》 SCIE EI CAS CSCD 2024年第3期1569-1583,共15页
With the successful application and breakthrough of deep learning technology in image segmentation,there has been continuous development in the field of seismic facies interpretation using convolutional neural network... With the successful application and breakthrough of deep learning technology in image segmentation,there has been continuous development in the field of seismic facies interpretation using convolutional neural networks.These intelligent and automated methods significantly reduce manual labor,particularly in the laborious task of manually labeling seismic facies.However,the extensive demand for training data imposes limitations on their wider application.To overcome this challenge,we adopt the UNet architecture as the foundational network structure for seismic facies classification,which has demonstrated effective segmentation results even with small-sample training data.Additionally,we integrate spatial pyramid pooling and dilated convolution modules into the network architecture to enhance the perception of spatial information across a broader range.The seismic facies classification test on the public data from the F3 block verifies the superior performance of our proposed improved network structure in delineating seismic facies boundaries.Comparative analysis against the traditional UNet model reveals that our method achieves more accurate predictive classification results,as evidenced by various evaluation metrics for image segmentation.Obviously,the classification accuracy reaches an impressive 96%.Furthermore,the results of seismic facies classification in the seismic slice dimension provide further confirmation of the superior performance of our proposed method,which accurately defines the range of different seismic facies.This approach holds significant potential for analyzing geological patterns and extracting valuable depositional information. 展开更多
关键词 Seismic facies interpretation Dilated convolution Spatial pyramid pooling Internal feature maps Compound loss function
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