内镜用套扎器与经内镜黏膜下隧道法切除食管黏膜下肿瘤的对比研究

目的对比分析内镜用套扎器与经内镜黏膜下隧道肿瘤切除术(STER)切除食管黏膜下肿瘤(SMTs)的临床效果。方法回顾性分析66例采用经内镜法切除的食管SMTs患者的临床资料,其中套扎组35例[经内镜套扎器套扎法(直径<10 mm)],STER组31例,对比分析两组手术时间、术中出血量、术后并发症(术后穿孔、出血、气胸和进食障碍)、术后住院时间和手术费用等指标。结果套扎组手术时间较STER组短[(8.9±1.1)和(62.3±2.8)min],手术费用较STER组少[(5126.8±26.5)和(15721.3±39.6)元],术中出血量较STER组少[(5.6±1.7)和(42.3±3.5)mL],两组比较,差异均有统计学意义(P<0.05);两组患者术后住院时间和术后并发症发生率比较,差异均无统计学意义(P>0.05)。结论治疗直径<10 mm的食管黏膜肌层或黏膜下层肿瘤,经内镜套扎法在手术时间、术中出血量和手术费用方面均优于STER组,两种手术方法的住院时间和术后并发症发生率无差异,值得临床推广应用。

Improving the detecting efficiency of suspected gastrointestinal tumors with dual-time-point 18F-FDG PET/CT

We conducted a retrospective analysis of 221 subjects with 256 suspected gastrointestinal lesions from2007 to 2015 to explore the detecting efficiency of dualtime-point fluorine-18 fludeoxyglucose(^(18)F-FDG) positron emission tomography/computed tomography(PET/CT)and pathology examination. The abdominal delayed PET/CT was performed within 45 min of the conventional scan.The change in maximum standardized uptake value(ASUV_(max)) and morphological features of the suspected lesions between the conventional and dual-time-point PET/CT were compared. The sensitivity, specificity, positive predictive value, and negative predictive value(NPV) of conventional PET/CT were 81.6%(84/103), 56.2%(86/153), 55.6%(84/151), and 81.9%(86/105), respectively.Those of dual-time-point PET/CT were 94.1%(97/103),78.4%(120/153), 74.6%(97/130), and 95.2%(120/126),respectively. There was a significant difference between the conventional and dual-time-point PET/CT(P < 0.005).The SUV_(early) and the %△SUV_(max) could not present more information in differential diagnoses, but the rate of tumors with increased SUVdelay accounted for 79.6%(82/103) and more than that of nonneoplastic lesions(15.5%, 29/187)(x^2= 115.5, P < 0.01). Therefore, the dual-time-point^(18)F-FDG PET/CT had a higher sensitivity and NPV than the conventional PET/CT to detect gastrointestinal tumors.The constant morphology and increased SUV_(delay) help to detect the tumors and adding delayed imaging on the locality will be an effective method when we accidentally find a suspected gastrointestinal tumor on the conventional PET/CT images.

Electrochemical investigation of the anode processes in LiF-NdF3 melt with low oxygen content

The oxidation of oxygen ions and the generation of an anode effect at a low oxygen content of 150 mg/kg were discussed in this paper.Cyclic voltammetry and square-wave voltammetry tests were conducted to explore the anodic processes of LiF-NdF_(3)melt after a lengthy period of pre-electrolysis purification at 1000℃(during which the oxygen content reduced from 413 to 150 mg/kg).The oxidation process of oxygen ions was found to have two stages:oxidation product adsorption and CO/CO_(2)gas evolution.The adsorption stage was controlled by diffusion,whereas the gas evolution was controlled by the electrochemical reaction.In comparison with oxygen content of 413 mg/kg,the decrease in the amplitude of the current at low oxygen content of 150 mg/kg was much gentler during the forward scanning process when the anode effect occurred.Fluorine-ion oxidation peaks that occurred at about 4.2 V vs.Li/Li+could be clearly observed in the reverse scanning processes,in which fluorine ions were oxidized and perfluorocarbons were produced,which resulted in an anode effect.

Waveform inversion and analysis of an unusual earthquake swarm in the Boshan mining area, Shandong Province, China

Moment tensor solutions were retrieved for the earthquake swarm that occurred during November and December 2010 in the Boshan mining area, Shandong Province, China. The results showed that the double-couple components in the source mechanisms were higher at the beginning of the swarm and consisted mainly of shear faulting controlled by tectonic stress. The subsequent events had significant non-double-couple components, indicating tensile faulting. The double-couple components predominately presented as normal faulting and the P axes were orientated almost vertically. The slip vectors of the swarm events were relatively stable. With reference to the tectonic features near the epicenter, we concluded that the swarm was a result of subordinate fault motion related to the Wangmu Mountain fault and that high-pressure pore fluids played a crucial role in the activity of the earthquake swarm.

A residual-based message passing algorithm for constraint satisfaction problems

Message passing algorithms,whose iterative nature captures complicated interactions among interconnected variables in complex systems and extracts information from the fixed point of iterated messages,provide a powerful toolkit in tackling hard computational tasks in optimization,inference,and learning problems.In the context of constraint satisfaction problems(CSPs),when a control parameter(such as constraint density)is tuned,multiple threshold phenomena emerge,signaling fundamental structural transitions in their solution space.Finding solutions around these transition points is exceedingly challenging for algorithm design,where message passing algorithms suffer from a large message fiuctuation far from convergence.Here we introduce a residual-based updating step into message passing algorithms,in which messages with large variation between consecutive steps are given high priority in the updating process.For the specific example of model RB(revised B),a typical prototype of random CSPs with growing domains,we show that our algorithm improves the convergence of message updating and increases the success probability in finding solutions around the satisfiability threshold with a low computational cost.Our approach to message passing algorithms should be of value for exploring their power in developing algorithms to find ground-state solutions and understand the detailed structure of solution space of hard optimization problems.

Effects of Processing Variables on Microstructure and Yield Ratio of High Strength Constructional Steels

The process of“controlled rolling＋relaxation＋ultra fast cooling（UFC）”for high strength constructional steel with low yield ratio was presented.Microstructure and corresponding relationship with low yield ratio were investigated.The results showed that the constructional steels with multiphase microstructure of bainitic ferrite,martensite-austenite（M-A）and lath bainite were obtained through the creative process.The grain size decreased with the decrease in finish rolling temperature,which enhanced the strength by the grain refinement strengthening.The proper relaxation treatment promoted the bainitic ferrite lath width and the formation of blocky M-A constituent.In addition,both the tensile and yield strength increased with the decrease in finish rolling temperature and UFC final temperature,but the yield strength increased more significantly than tensile strength,which caused the increase in yield ratio.By using the process of“controlled rolling＋relaxation＋ultra fast cooling”,the excellent comprehensive mechanical properties of 780 MPa grade constructional steels of 12-40 mm in thickness were achieved.